prompt_front: Now, answer the following question based on the text below, only give me the answer and do not output any other words.

Question: What is the maximum radius of the emitting region for the black body model?

Read the following text and answer briefly.

Context 1: \section{Introduction}

The publicly available XMM-Newton slew data covers to date around 35\%
of the sky  The soft band (0 2$-$2 keV) sensitivity limit of the slews
(6$\times10^{-13}$\,ergs cm$^{-2}$ s$^{-1}$) is close to that of the
ROSAT All-Sky Survey (RASS; Voges et al \ 1999), and in the medium
(2$-$12 keV) band, the slew data goes significantly deeper
(4$\times10^{-12}$\,ergs cm$^{-2}$ s$^{-1}$) than all other previous
large area surveys  Over 7700 individual sources have so far been
detected to a positional accuracy of 8\arcsec   For details on the
the construction and
characteristics of the first released XMM-Newton slew survey
catalogue, see Saxton et al  (2008)  For details of the initial
science results from the slew survey, see Read et al  (2006) 

The comparison of XMM-Newton slew data with the RASS is now giving,
for the first time, the opportunity to find exotic, extreme
high-variability X-ray bursting objects, e g  tidal disruption
candidates (Esquej et al  2007), and also Galactic novae, flare stars,
and flaring white dwarfs, plus eclipsing binaries, AGN and blazars  It
is only with such a large-area survey as the XMM-Newton Slew Survey,
that transient events as these have a chance of being caught 

One such rare event, XMMSL1~J060636 2-694933, which we here show to be
a new Classical Nova, was discovered in an XMM-Newton slew from 18th
July 2006 at a very high count rate of 23 3\,ct s$^{-1}$ (EPIC-pn:
0 2$-$2\,keV)  

Classical novae (see Bode \& Evans 2008 for a review) occur in
interacting binary systems consisting of a white dwarf primary star
and a lower-mass secondary star  The nova itself is a cataclysmic
nuclear explosion caused by the accretion of material (via Roche Lobe
overflow or wind accretion) from the secondary star onto the surface
of the white dwarf; here the pressure and temperature at the base of
the accreted material becomes sufficient to trigger a thermonuclear
runaway  A recent review of the thermonuclear processes powering
classical novae can be found in Starrfield et al \ (2008)   The
accreted material is partially expelled, obscuring the X-ray emission
from the surface of the white dwarf  At later stages, the ejected
material expands further and becomes optically thin, revealing the
nuclear burning on the surface of the white dwarf   This emission
peaks in the soft X-ray regime and it is known as the super-soft
source (SSS) state (Krautter 2008)  Models of the classical nova SSS
state can be found in Tuchman \& Truran (1998) and Sala \& Hernanz
(2005) 

Though many classical novae have been observed in X-rays in their SSS
states (Ness et al \ (2007) for example discuss several examples observed with
Swift), it is in the optical band, early in their outbursts, that
classical novae are almost always discovered  This is because they are
intrinsically optically bright and easily found in inexpensive
wide-area shallow surveys   XMMSL1~J060636 2-694933 is very unusual
therefore in that it has been discovered, as we shall see, later in
its evolution, in the SSS X-ray state 

In this paper we describe the XMM-Newton slew observations
(Section~2), and the follow-up X-ray observations by the Swift XRT
(Section~3) and XMM-Newton (Section~4)  Multiwavelength observations
with Swift-UVOT, Magellan and ASAS are described in Section~5  We then
present a discussion of the results (Section~6), and conclusions 



\begin{table*}[t]
  \caption[]
  {Details of the four XMM-Newton Slew observations and the single (Rev \,1378) 
    dedicated XMM-Newton pointed observation  XMM-Newton revolution, date and observation ID 
    are tabulated, together with the 0 2$-$2 0\,keV X-ray properties of XMMSL1~J060636 2-694933;  
    position, background-subtracted counts, exposure, count-rate, and detection likelihood  For the 
    Rev \,1378 dedicated observation, these properties are given for all the EPIC cameras combined   
    For the slew observations, only the EPIC-pn values are given  In the first two slews the source 
    was not detected, and upper limits are shown in the table }
  \centering
\begin{tabular}{lccccrrrr}
\hline
Rev  & Date & Obs \,ID & RA(J2000)   & Dec(J2000) & Counts         & Exposure & Count rate  & Lik  \\ 
     & (UT) &        &     &            &                & (s) & (s$^{-1}$)  &      \\ \hline 
 351 (slew) & 07/11/01 &  9035100003  &        &               & $<$3 6     & 8 8 & $<$0 41 & $<$$\sim$8      \\
 750 (slew) & 12/01/04 &  9075000003  &        &               & $<$3 2     & 17 3 & $<$0 18 & $<$$\sim$8      \\  
1210 (slew )& 18/07/06 &  9121000003  & 06:06:36 2 & -69:49:33 & 228 8$\pm$14 1 & 9 8 & 23 4$\pm$1 4 & 1777 1   \\ 
1246 (slew) & 28/09/06 &  9121460003  & 06:06:36 5 & -69:49:38 &  12 9$\pm$2 4  & 3 4 &  3 8$\pm$0 7 &   54 7   \\
\vspace{-3 5mm}\\
\hline 
1378 (pointed) & 19/06/07 &  0510010501  & 06:06:36 5 & -69:49:37 & 1511 0$\pm$44 8 & 8940 0 &  0 20$\pm$0 01 & 4630 4          \\
\hline
\end{tabular}
\label{slewtable}
\end{table*}

\section{XMM-Newton slew observations}

XMMSL1~J060636 2-694933 was discovered in XMM-Newton slew 9121000003
from revolution 1210 on 18th July 2006  Details of the standard
XMM-Newton slew data reduction and analysis used, plus the
source-searching and catalogue cross-correlation etc , are presented
in Saxton et al   (2008) 

The source passed through the EPIC-pn detector in 14\,s, at a small
off-axis angle, such that an effective vignetting-corrected soft band
(0 2$-$2\,keV) exposure time of 9 8\,s was achieved   A total of 229
source counts lie within a radius of 20\arcsec, yielding a (EPIC-pn:
0 2$-$2\,keV) count rate of 23 4\,ct s$^{-1}$ 

The source is seen to have no cross-correlation identifications in the
RASS, and no other multiwavelength candidates within 30\arcsec\ in
Simbad\footnote{http://simbad u-strasbg fr/simbad/},
NED\footnote{http://nedwww ipac caltech edu/index html}, and
HEASARC\footnote{http://heasarc gsfc nasa gov/}  The position of the
source in the sky is such that it lies apparently at the outer eastern
edge of the LMC 

XMM-Newton has slewed over this region of sky a number of times, and
though nothing was detected in previous slews from 7th November 2001
and 12th January 2004, the source was seen again on 28th September
2006 (rev \,1246, 72 days after the rev \,1210 discovery), at the same
position, but at a reduced flux level (3 8\,ct s$^{-1}$; EPIC-pn:
0 2$-$2\,keV)   i e  it had reduced in flux by a factor of $\approx$6
in 72 days  XMM-Newton has not slewed over this area of sky since
rev \,1246  Details of the relevant XMM-Newton slews, together with
the (0 2$-$2\,keV) EPIC-pn source position, detected source counts,
count rate and detection likelihood are given in
Table~\ref{slewtable} 

The fact that XMMSL1 J060636 2-694933 is detected in the total-band
(0 2$-$12\,keV) and the soft-band (0 2$-$2\,keV), whilst effectively
zero counts are seen in the hard-band (2$-$12\,keV), is immediately
indicative of the source being very soft  

The moderately high count rate indicates that the spectrum is affected
by pile-up (the on-axis limit is 6\,ct s$^{-1}$ for EPIC-pn full-frame
mode
\footnote{http://xmm esac esa int/external/xmm\_user\_support/documentation
  /uhb\_2 5/index html})  This distorts the spectrum and makes
quantitative spectral analysis of the slew data difficult  We
minimized these effects by following the standard procedure, i e 
ignoring the central part of the Point Spread Function (PSF), and
extracted an event spectrum (containing single and double events) of
the source from within an annulus of 5\arcsec$-$30\arcsec\ radius,
centred on the source position  Unresolved problems associated with
the motion of sources across the detector still exist within slew
data, and approximations currently have to be made when calculating
the associated effective area and detector response matrix files  In
order to perform qualitative spectral analysis, an effective area file
was generated by averaging the individual core-removed effective area
files at 9 different positions along the detector track made by the
source  This accounts for the removal of the piled-up core, and takes
the vignetting and PSF variations into account to a good
approximation   Individual BACKSCAL values have been set by hand, as
have the EXPOSURE values, estimated by calculating the distance
travelled by the source in detector coordinates and finding the time
taken to do this, given a 90\,deg\,hr$^{-1}$ slew speed, then
subtracting the appropriate fractions for chip gaps and bad pixels 
For the response matrix, we used the equivalent canned detector
response matrix for the vignetting-weighted average source position,
for single plus double events and for full-frame mode:
epn\_ff20\_sdY6\_v6 9 rmf  A background spectrum was extracted from a
much larger circular region close to the source and at a similar
off-axis angle 

To fit the slew spectral data, and indeed all the high-energy spectra
in the present paper, the
XSPEC\footnote{http://heasarc gsfc nasa gov/docs/xanadu/xspec/}
spectral fitting package has been used  As $\chi^2$ minimization is
not valid when fitting spectra of low statistical quality, for the
fitting of the slew spectrum (and all the spectral fitting in the
present paper), C-statistics have been used  To take into account the
absorbing column along the line of sight, the {\em wabs} model with
the {\em wilm} cosmic abundance table (Wilms et al \ 2000) has been
used throughout the paper  All the errors quoted in the present paper
are 90\% confidence intervals, unless otherwise stated 

The rev \,1210 slew spectrum shows that the source is very soft, and
appears consistent with a 63$_{-10}^{+12}$\,eV black body, absorbed by
a hydrogen column density of
8 2$_{-4 1}^{+5 4}\times10^{20}$\,cm$^{-2}$  The fit is good, with a
P-statistic value of 0 11, obtained via the XSPEC {\em goodness}
command for this fit, based on 5000 random simulations  The best-fit
hydrogen column is equal to the full Galactic hydrogen column in the
direction of the source (8 0$\pm{1 1}\times10^{20}$\,cm$^{-2}$; Dickey
\& Lockman, 1990, calculated via the FTOOL {\em
  nh}\footnote{http://heasarc gsfc nasa gov/lheasoft/ftools/fhelp/nh txt}) 
The slew spectrum, plus the best fit simple black body model and the
deviations from the model, are shown in Fig \,\ref{slewspec}  The
observed count rate corresponds to a (0 2$-$2\,keV) flux, corrected
for the removal of the saturated PSF core, of
4 8$^{+2 7}_{-1 6}\times10^{-11}$\,ergs cm$^{-2}$ s$^{-1}$ (an
increase in flux over the RASS upper limit, assuming the same spectral
model, by a factor of more than 500) 

Simple power-law, thermal Bremmstrahlung, and other optically thin hot
plasma models are unable to fit the spectrum adequately well   Given
that we later are able to identify the source as a nova (Section~5 2),
then the black-body model will likely be a good approximation 
Furthermore, as we have obtained here a moderate number of slew
counts, the more physically realistic, though more complex atmosphere
model for CO white dwarfs of MacDonald \& Vennes (1991), provided by
K \,Page (private communication), was attempted   This model, used
e g  to model the nova V1974 Cyg (Balman et al \ 1998), yielded a
marginal fit (and not formally a more statistically significant fit;
P-statistic = 0 03, based on 5000 random simulations), with an
effective temperature of 70$^{+8}_{-6}$\,eV, an $N_{\rm H}$ of
3 7$^{+3 2}_{-2 5}$$\times$$10^{20}$\,cm$^{-2}$, and a PSF-corrected
(0 2$-$2\,keV) flux of 4 5$^{+1 3}_{-1 8}\times10^{-11}$\,ergs
cm$^{-2}$ s$^{-1}$  Note that a smaller $N_{\rm H}$ (though perhaps
still consistent with the full Galactic hydrogen column) is now
obtained using the white dwarf atmosphere model  (Note that the
MacDonald \& Vennes (1991) ONe white dwarf atmosphere model was also
attempted, but yielded a marginally worse fit than the CO white dwarf
atmosphere model; only the CO atmosphere model has been used in the
subsequent analysis) 

It is well known (e g  Krautter et al \ 1996) that, because of the
energy-dependent opacity in the white dwarf atmosphere, fits to super
soft source novae spectra with black body models give larger fluxes
and lower temperatures than atmosphere models fit to the same spectra,
and this is seen in the present case  Thus the black body model
requires a larger $N_{\rm H}$ to fit the same data than the atmosphere
model, as is seen  

The model normalizations, corrected for the removal
of the saturated PSF core, can be used to derive an approximate
distance to the source   If we assume a typical emitting region for
the white dwarf atmosphere to be of spherical radius 10$^{9}$\,cm,
then, for the black body model, this distance turns out to be
20$^{+31}_{-10}$\,kpc  The effects discussed above however can lead to
usage of the black body model giving rise to an underestimation of the
distance   For the white dwarf atmosphere model, a larger distance of
71$^{+27}_{-23}$\,kpc is obtained  Both estimates are consistent with
the distance to the LMC ($\sim$50\,kpc, see Section~6), and assuming a
distance of 50\,kpc, the black body derived flux corresponds to a
(pile-up corrected) 0 2$-$2\,keV X-ray luminosity of
1 4$^{+0 8}_{-0 5}\times10^{37}$\,ergs s$^{-1}$ 


\begin{figure}
\centering
\includegraphics[bb=100 20 575 700,clip,width=6 0cm,angle=270]{12082f1 ps}
\caption{XMM-Newton Slew spectrum of XMMSL1 J060636 2-694933 from
  XMM-Newton revolution 1210   The data points (crosses; adjacent data
  bins having been grouped together for the plot to have a significance of at least
  3) have been fitted with a black body model (kT=63\,eV; see text) 
  The solid line shows the best fit to the spectrum  The ratio of the
  data to the best fit model is shown in the lower panel }
\label{slewspec}
\end{figure}


\section{Swift XRT X-ray observations}

We requested and received a prompt observation with Swift of this
source before it moved out of the Swift visibility window in April
2007  We received over 14\,ksec of Swift-XRT time in 7
separate observations and the details of these observations are listed
in Table~\ref{xrttable}  All of the observations were in photon
counting mode and none of the observations showed any times of
significant high-BG flux  In none of the observations did the source
position coincide with any of the dead (micrometeorite-induced)
detector columns  The analysis has been performed using HEASOFT
v6 1 2  The individual XRT observations were astrometrically-corrected
and then stacked to ascertain a best Swift-XRT position $-$ this was
found to be 06 06 37 00 -69 49 33 9 (with a 90\% error radius of
4 0\arcsec)  Source counts were then extracted from each observation
from a circle of radius of 40\arcsec\ at this position  Background
counts were extracted from each observation from large-radius
off-source circles close to the source position  Source counts and
count rates for the individual XRT observations are given in
Table~\ref{xrttable} 


\begin{table}
  \caption[]{Details of the Swift-XRT observations (observation ID, observation date and 
    cleaned exposure time) are tabulated, together with the total (0 2$-$2 0\,keV) background-subtracted 
    counts and count rate from XMMSL1 J060636 2-694933 (see text) }
  \centering
\begin{tabular}{ccrrr}
\hline
ID          & Date     & Exp  & Counts       & Count rate       \\ 
            &   (UT)   &  (s) &              & (s$^{-1}$)        \\ \hline 
00030895001 & 28/02/07 & 1955 & 23 9$\pm$5 1 & 0 0122$\pm$0 0026  \\
00030895002 & 07/03/07 & 1796 & 15 8$\pm$4 2 & 0 0088$\pm$0 0024 \\
00030895003 & 08/03/07 & 1651 & 10 9$\pm$3 6 & 0 0066$\pm$0 0022 \\
00030895004 & 08/03/07 & 2547 & 20 6$\pm$4 8 & 0 0081$\pm$0 0019 \\
00030895005 & 10/03/07 & 2550 & 29 5$\pm$5 7 & 0 0116$\pm$0 0022 \\
00030895006 & 20/03/07 &  552 &  8 6$\pm$3 2 & 0 0156$\pm$0 0057 \\
00030895007 & 22/03/07 & 3391 & 24 4$\pm$5 4 & 0 0072$\pm$0 0016 \\
\hline
\end{tabular}
\label{xrttable}
\end{table}

The observation naturally fell into three time-separated groups, those
of obs \,1, obs \,2-5 and obs \,6-7  A similar analysis applied to
these groups (where the statistics are improved) gives rise to source
counts and count rates of 76 7$\pm$9 3\,counts and
0 0090$\pm$0 0011\,ct~s$^{-1}$ (for obs \,2-5), and
33 0$\pm$6 2\,counts and 0 0084$\pm$0 0016\,ct~s$^{-1}$ (for
obs \,6-7)  (Analysis of all the data together yields
133 6$\pm$12 3\,counts and 0 0092$\pm$0 0009\,ct~s$^{-1}$)  

A spectrum was extracted from all the Swift-XRT data from a 40\arcsec\
radius circle, using grades 0$-$12, centred on the Swift-XRT position 
A background spectrum was extracted again from all the Swift-XRT data,
from large-radius off-source circles close to the source position  An
ARF file was created using {\em xrtmkarf} and the appropriate RMF
(swxpc0to12\_20010101v008 rmf) from the Swift-XRT Calibration Database
was obtained 

Standard spectral models were again fit to the spectral data using
XSPEC  Again, C-statistics were used, as was the {\em wabs} absorption
model with the {\em wilm} cosmic abundance table  It was again 
obvious that only a very soft spectrum would be appropriate for the
data, and the only simple model that was able to fit the data
adequately was a black-body model of temperature
$kT$=$59^{+14}_{-10}$\,eV, with an absorbing hydrogen column of
9 5$^{+5 0}_{-3 9}$$\times$$10^{20}$\,cm$^{-2}$  No sufficiently constrained parameters could
be obtained using the CO white dwarf atmosphere model (MacDonald \&
Vennes 1991)  The Swift-XRT spectrum, together with the best-fit black
body model is shown in Fig \,\ref{xrtspec}  The corresponding
(0 2$-$2 0\,keV) flux is 2 7$^{+0 7}_{-1 2}\times10^{-13}$\,ergs
cm$^{-2}$ s$^{-1}$ (i e  a reduction by more than a factor 100 from
the XMM-Newton slew discovery flux), and the X-ray luminosity, for the
assumed distance of 50\,kpc, is 8 0$^{+2 2}_{-3 5}\times10^{34}$\,ergs
s$^{-1}$ 

\begin{figure}
\centering
\includegraphics[bb=100 15 580 710,clip,width=6 0cm,angle=270]{12082f2 ps}
\caption{Swift-XRT spectrum from XMMSL1 J060636 2-694933  The data
  points (crosses; adjacent data bins having been grouped together for
  the plot to have a significance of at least 3) have been fitted with
  a black body model (kT=59\,eV; see text)  The source has faded by a
  factor of $>100$ since the XMM-Newton revolution 1210 slew
  discovery  The solid line show the best fit to the spectra   The
  ratio of the data to the best fit model is shown in the lower panel 
}
\label{xrtspec}
\end{figure}

A cautious estimate of the size of the emitting region can be obtained
from the model normalization; the assumed distance of 50\,kpc yields a
maximum radius of 4 5$\times$10$^{8}$\,cm (the fit normalization is
essentially unconstrained at the lower bound)   Though great care
should be taken in interpreting this result, as the black body model
is possibly overestimating the luminosity, this obtained radius is
still consistent with that of moderately massive ($>$1 1$M_{\odot}$)
white dwarfs (Hamada \& Salpeter 1961), i e \,the whole white dwarf
surface may still be emitting at 59\,eV 

\section{Dedicated XMM-Newton observations}

We were granted an XMM-Newton Target of Opportunity (ToO) observation,
once the source became again visible to XMM-Newton, and a 10\,ks
XMM-Newton EPIC observation was made on 19th June 2007 (see
Table~\ref{slewtable})  All the XMM-Newton EPIC data, i e   the data
from the two MOS cameras and the single pn camera, were taken in
full-frame mode with the thin filter in place   These data from the
three EPIC instruments have been reprocessed using the standard
procedures in XMM-Newton SAS (Science Analysis System) $-$ v 7 1 0 
Periods of high-background, of which there were very few, were
filtered out of each dataset by creating a high-energy 10$-$15\,keV
lightcurve of single events over the entire field of view, and
selecting times when this lightcurve peaked above 0 75\,ct s$^{-1}$
(for pn) or 0 25\,ct s$^{-1}$ (for MOS)  This resulted in
$\approx$9 4(8 0)\,ks of low-background MOS(pn) data  Details of this dedicated
XMM-Newton observation, together with source position, and
(0 2$-$2\,keV) all-EPIC combined (pn, MOS1, MOS2) detected source
counts, count rate and detection likelihood are given in
Table~\ref{slewtable} 

Source spectra, containing single and double events, were extracted
from the datasets from circles (none of the data were now piled up)
centred on the source position  An extraction radius, estimated from
where the radial surface brightness profile was seen to fall to the
surrounding background level, was set to 30\arcsec  Background spectra
were extracted from each cleaned dataset from a 40\arcsec$-$80\arcsec\
annulus centred on the source position  Point sources seen to
contaminate these larger-area background spectra were removed from the
background spectra to a radius of 60\arcsec  ARF files were created
for the source spectra, and were checked to confirm that the correct
extraction area calculations had been performed  Finally RMF response
files were generated 
 
Standard spectral models were again fit to the spectral data using
XSPEC  Once again it was obvious that only a very soft model would fit the data; the only
simple model that was able to fit the data well (a P-statistic = 0 17,
based on 5000 random simulations) was a black-body model of
temperature $kT$=70$^{+3}_{-4}$\,eV, with an absorbing hydrogen column
of 6 9$^{+1 0}_{-1 6}\times10^{20}$\,cm$^{-2}$  The spectrum, together with this best-fit
model are shown in Fig \,\ref{xmmspec}  The corresponding
(0 2$-$2 0\,keV) flux is only marginally less than the Swift-XRT value
at 2 2$^{+0 8}_{-0 9}\times10^{-13}$\,ergs cm$^{-2}$ s$^{-1}$ and the
X-ray luminosity (for the assumed distance of 50\,kpc) is
6 7$^{+2 5}_{-2 8}\times10^{34}$\,ergs s$^{-1}$ 

\begin{figure}
\centering
\includegraphics[bb=110 15 570 705,clip,width=6 0cm,angle=270]{12082f3 ps}
\caption{XMM-Newton ToO spectrum from XMMSL1 J060636 2-694933  The
  data points (crosses; adjacent data bins having been grouped
  together for the plot to have a significance of at least 3)) have
  been fitted again with a black body model (kT=70\,eV) (see text) 
  EPIC-pn data is shown in black, with EPIC-MOS1 in red and EPIC-MOS2
  in green  The solid lines show the best fit to the spectra   The
  ratios of the data to the best fit model are shown in the lower
  panel }
\label{xmmspec}
\end{figure}

Given that, in this XMM-Newton ToO observation, we had obtained a
larger number of counts ($\raisebox{-1mm}{$\stackrel{>}{\sim}$}$1500 over the 3 EPIC cameras), the
physically more realistic CO white dwarf atmosphere model (MacDonald \&
Vennes 1991) was also attempted  This yielded a marginal fit (and formally
a no more statistically significant fit; P-statistic = 0 04, based on
5000 random simulations), with an effective temperature of
73$^{+3}_{-2}$\,eV, and an $N_{\rm H}$ of
3 4$^{+0 8}_{-0 8}$$\times$$10^{20}$\,cm$^{-2}$  Again, usage of the black body model results
in a larger fitted $N_{\rm H}$ and a lower fitted temperature than
with the atmosphere model  


As before, the model normalization can be used to obtain a cautious
estimate of the size of the emitting region  For the assumed distance
of 50\,kpc, then the black body model returns an emitting region
radius of only 1 3$\pm$0 2$\times$10$^{8}$\,cm   Again care should be
taken, as this may be an overestimation, the black body model having
perhaps overestimated the luminosity  For the white dwarf atmosphere
model, a smaller radius of 0 4$\pm$0 1$\times$10$^{8}$\,cm is
obtained  Note further that the assumption of a larger distance (see
Section~6) would result in a proportionally larger emitting radius 
The range in allowed radius therefore is quite large, and it is not
impossible for for the whole of the white dwarf surface to be emitting
at 70\,eV  If this is the case, then the white dwarf would have to be
at the high end of the mass range ($>$1 2$M_{\odot}$; Hamada \&
Salpeter 1961)  It may be the case then that we are at this point at,
or close to the end of the SSS phase, where the effective temperature
has reached a maximum (Sala \& Hernanz 2005), as is tentatively seen
in the spectral fitting results, and where the photospheric radius has
reached a minimum, close to the white dwarf radius 


\subsection{X-ray variability}

The full (XMM-Newton slew plus Swift-XRT plus XMM-Newton ToO) X-ray
lightcurve of XMMSL1 J060636 2-694933 is shown in
Fig \,\ref{lightcurve}  The calculated (0 2$-$2 0\,keV) flux values
are shown plotted against the number of days since the rev \,1210
XMM-Newton Slew discovery  The first two data points are the
rev \,1210 and the rev \,1246 XMM-Newton Slew observations  Then the
three nested Swift-XRT points are shown and finally the XMM-Newton ToO
observation  The level of RASS upper limit is shown to the bottom
left  The (0 2$-$2 0\,keV) X-ray flux is seen to have dropped by more
than two orders of magnitude in 230 days since the discovery, but is
then seen to have levelled off for the next 120 days, at a level still
$\approx$3 times that of the RASS  Finally, no evidence for any
short-term variability (using time bins down to 100\,s) is seen in the
highest statistic continuous X-ray lightcurve (the $\approx$8 0\,ksec
background-filtered EPIC-pn lightcurve) obtained from the 19/06/07
XMM-Newton observation 

\begin{figure}
\centering
\includegraphics[bb=60 60 550 454,clip,width=8 7cm]{12082f4 ps}
\caption{The full X-ray lightcurve of XMMSL1 J060636 2-694933  Plotted
  are the calculated (0 2$-$2 0\,keV) flux values versus time  The
  first point is the rev \,1210 XMM-Newton Slew observation, then the
  rev \,1246 XMM-Newton Slew observation  The three nested Swift-XRT points
  are shown next and finally the XMM-Newton ToO observation  The RASS upper
  limit is shown bottom left  }
\label{lightcurve}
\end{figure}


\section{Multi-wavelength Follow-up}

\subsection{Swift UVOT}

For the Feb/Mar 2007 Swift observations, we arranged for both the
Swift UVOT-B filter and the UVOT-UVW2 filters to be used in an
approximate exposure time ratio of 1:5, thus ensuring roughly equal
numbers of counts in the two bands (though there is a spectral type
dependency here)  Swift UVOT images in these two filters of the area
of sky around XMMSL1 J060636 2-694933 are shown in Fig \,\ref{uvot} 

Prior to the Swift UVOT observations, a `best-guess' to the possible
candidate optical/IR counterpart would have been the USNO-A2 0 source
0150-04066298 (B~mag: 17 4, R~mag: 16 1), seen 4\arcsec\ south of the
XMM-Newton slew position  The UVOT images however immediately showed
that the optically fainter source at position RA, Dec (J2000) = 06 06
36 4, -69 49 34 3 (error radius: ~0 5\arcsec) was a very strong UVW2
source and very blue, and was very likely the true counterpart to
XMMSL1~J060636 2-694933  (The UVW2 filter spans approximately
800\AA\,, centred at $\approx$1900\AA)

\begin{figure}
\centering
\includegraphics[bb=-82 210 695 585,clip,width=8 7cm]{12082f5 ps}
\caption{Swift UVOT images of the field around XMMSL1 J060636 2-694933 from observation
  00030895002  Left shows the UVOT B-filter and right shows the the
  UVOT UVW2-filter  The large circle is a 20\arcsec\ radius circle around
  the XMM-Newton Slew position  The small circle in the UVW2 image around the
  bright source is reproduced in the B image, indicating that a faint
  optical source is also visible at this position }
\label{uvot}
\end{figure}

The Swift UVOT pipeline processed data were analysed using the UVOT
photometry package {\em uvotsource} released with
FTOOLs\footnote{http://heasarc nasa gov/lheasoft/ftools/ftools\_menu html} 
This package performs aperture photometry on pre-specified source and
background regions, accounting for photometric- (via PSF fitting) and
coincidence loss- effects using the UVOT calibration files  Source
counts were extracted using a 5\arcsec\ radius aperture centred on the
source, while for the background we used a 10\arcsec\ radius aperture
located in a nearby source-free region   We used a larger background
aperture to effectively smooth over the modulo-8 fixed pattern noise
present in UVOT observations and to improve the statistics of the
background counts  Source counts were converted to UVOT UV-magnitudes
using the UVW2 zero-point calibration released with version~2 8 (Build
22) of the CALDB  The source is seen (see Fig \,\ref{uvotlc}) to be
roughly constant over the short duration of the Swift observations,
with a suggestion of a decline towards the end  This is in keeping
with the general form of the X-ray lightcurve (Fig \,\ref{lightcurve})
at this time 

\begin{figure}
\centering
\includegraphics[bb=80 70 535 380,clip,width=8 7cm]{12082f6 ps}
\caption{Variation of the UVW2 magnitude of the bright UV source
  during the Swift observations  The same time axis as
  Fig \,\ref{lightcurve} has been used to aid comparison, and a zoom
  is also shown  The UVW2 filter was only employed during observations
  00030895002, 00030895004, 00030895005, 00030895006 \& 00030895007
  (hence the points span the dates 07/03/07 to 22/03/07)  The errors here are 1-$\sigma$  }
\label{uvotlc}
\end{figure}

It is possible to include the UVOT-detected flux with the XRT spectrum
described in Section~3  UVOT files, created using {\em uvot2pha} for
the five observations (00030895002, 00030895004, 00030895005,
00030895006 \& 00030895007) where the UVW2 filter was employed, were
incorporated into {\em xspec}, along with the appropriate response
file (swuw2\_20041120v104 rsp) from the Swift-XRT Calibration
Database  We attempted to fit a single black-body spectrum to the
Swift-XRT+UV data (again using C-statistics, the {\em wabs} absorption
model and the {\em wilm} cosmic abundance table, plus the inclusion of
the {\em xspec-redden} component to model the absorption in the UV
band)  The best fit however, with a much lower temperature of
$kT$=$36^{+3}_{-4}$\,eV, is a very poor fit to the data; we obtain a
{\em goodness} P-statistic value of 0 00, based on 5000 random
simulations  This notwithstanding, a flux in the UVW2
(1 57$-$7 77\,eV) band of 3 5$\pm{0 2}\times10^{-13}$\,ergs cm$^{-2}$
s$^{-1}$ can be obtained, corresponding to a UVW2 luminosity, for the
assumed distance of 50\,kpc, of 1 0$\pm{0 1}\times10^{35}$\,ergs
s$^{-1}$ 

The very poor single black-body fit above, plus the large change in
fitted temperature is strongly suggestive that a model other than, or
in addition to the XRT-derived kT=59\,eV black body model (Section~3)
should be used to describe the UVW2 data  As we have no UV data other
than in the UVW2 filter, all that can be done is to apply the
XRT-derived black body model to the UVW2+XRT data, and in doing this,
a large flux excess with respect to the XRT-derived black body model
is seen in the UVW2 band  This is shown in Fig \ref{xrtuvotspec}  This
excess in UV emission (most of the $10^{35}$\,ergs s$^{-1}$ discussed
above) is likely due to a combination of residual post-nova nuclear
burning on the surface of the white dwarf, plus accretion in the disk,
including from emission lines  The situation is likely to be rather
complex, depending on the structure of both the ejecta and the
accretion disk, and is beyond the scope of the present work, where we
only have sparse UV data   For a review of the UV emission from
classical novae, see Shore (2008) 


\begin{figure}
\centering
\includegraphics[bb=100 15 580 710,clip,width=6 0cm,angle=270]{12082f7 ps}
\caption{Swift-XRT spectrum (black) from XMMSL1 J060636 2-694933, plus
  the best-fit black-body model to this spectrum (Section~3; Fig \,2),
  but extending into the UV to the Swift-UVOT UVW2 flux points (coloured)
  (see text)  The data points are plotted such that adjacent data
  bins have been grouped together to have a significance of at least
  3  The solid line show the best fit to the Swift-XRT spectrum  The
  ratio of the data to the best fit model is shown in the lower
  panel }
\label{xrtuvotspec}
\end{figure}


\subsection{Magellan optical observations}

On Nov ~13, 14, and 15, 2007, XMMSL1~J060636 2--694933 was observed
with the Low--Dispersion Survey Spectrograph 3 (LDSS3) mounted on the
Magellan Clay telescope  Images were obtained through the Sloan
$g^\prime$, $r^\prime$ and $i^\prime$ filters  On Nov ~15, 2007
conditions were photometric and the Landolt field RU 149A was observed
to flux calibrate the data in the $g^\prime$, $r^\prime$ and
$i^\prime$--bands   The Landolt (1992) magnitudes of the standards
were converted to Sloan magnitudes using the transformations presented
in Smith et al \ (2002)  All the images were debiased and flatfielded
using dome flatfield frames  We applied aperture photometry on each of
the images using DAOPHOT in \textsc{IRAF}\footnote{\textsc {iraf} is
  distributed by the National Optical Astronomy Observatories} to
compute the instrumental magnitudes of the stars  Differential
photometry of the optical counterpart to XMMSL1~J060636 2-694933
(marked by an arrow in Fig ~\ref{magellan}) was performed with respect
to the field star (marked with a `c' in Fig ~\ref{magellan})  This was the
brightest isolated and unsaturated star common to all frames   The
calibrated brightness of this comparison star is $g'= 18 42 \pm 0 04$,
$r'= 17 85 \pm 0 06$ and $i'=17 58 \pm 0 07$ 

\begin{figure}
\centering
\includegraphics[bb=35 215 575 575,clip,width=8 7cm]{12082f8 ps}
\caption{Magellan Clay LDSS3 finder chart  The counterpart to
  XMMSL1~J060636 2-694933 (and the bright Swift-UVOT UVW2-filter
  source; Figs \ref{uvot}\&\ref{uvotlc}) is marked with an arrow  The comparison star is
  shown marked with a 'c' }
\label{magellan}
\end{figure}

In addition to the imaging observations described above, we have
obtained spectroscopic observations on Nov ~13, 14, and 15, 2007 using
the VPH All grism, which has 660 lines per mm, and employing a
1\arcsec\ wide slit  This set-up provides a mean dispersion of 2\AA\,
per pixel  For a slit width of 1 arcsecond and a mean seeing close to
1\arcsec, the mean spectral resolution is $\approx$10\AA  On Nov ~13, 2007
we took 4 exposures of 450\,s each, on Nov ~14, 2007 we took 2
exposures of 900\,s each, and on Nov ~15, 2007 we took one 1200\,s
exposure with the slit at the parallactic angle  The spectra were bias
and flatfield corrected, and extracted in \textsc{IRAF}  The
instrumental response was corrected using the spectrophotometric flux
calibrators LTT 3218 (Nov ~13), H600 (Nov ~14) and LTT 9293 (Nov ~15) 
Significant differences in the flux around H$\alpha$ are apparent with
the flux being 50\% higher during the Nov ~15, 2007 with respect to
the Nov ~13, 2007 observations  Since there is no evidence for
brightening in the $r^\prime$ images we attribute the difference to
the fact that the source was not observed at the parallactic angle on
Nov ~13 and 14, 2007  We exported the one dimensional spectra to the
spectral analysis software package \textsc{molly} for further
analysis 

\begin{figure}
\centering
\includegraphics[bb=70 30 600 800,clip,width=6 8cm,angle=270]{12082f9 ps}
\caption{Magellan Clay averaged optical spectrum of the optical source
  associated with XMMSL1 J060636 2-694933  The flux scaling is
  approximate  The prominent strong emission lines are marked (see
  text)  }
\label{optspec}
\end{figure}

We have averaged all spectra (see Fig ~\ref{optspec})  We find several
strong emission lines  The strongest of these emission lines are best
interpreted as due to [OIII] 4958 9\AA\, and 5006 9\AA\,, He~II at
4685 8\AA\, and a blend of the H$\alpha$ plus the [NII] at 6548 1\AA\,
and 6583 4\AA\,, lines found often in novae (Williams 1992)  In this
case the main [OIII] lines appear redshifted by approximately 2000\,km
s$^{-1}$  We interprete this as due to clumpy outflows in the nova
shell  The integrated light from different outflowing parts can also
explain the substructure that is present in the [OIII] lines  The
outflow velocities that we obtain for the H$\alpha$ and H$\beta$ lines
is $\approx$350\,km s$^{-1}$, hence less than that for the [OIII]
lines   Note that, if XMMSL1~J060636 2-694933 does reside within the
LMC, then the systematic line-of-sight recession velocity of the LMC,
262$\pm$3 4\,km~s$^{-1}$ (van der Marel et al \ 2002), should be taken
into account; i e \,a good fraction of the observed H$\alpha$ and H$\beta$
recession would then be due to the recession of the LMC itself 

\subsection{Long-term Optical light curve}

Analysis of archival robotic optical survey data from 3-minute CCD
exposures (pixel size 14\arcsec 8), obtained with a 70\,mm (200\,mm
focal length) f/2 8 telephoto lens in the course of the All Sky
Automated Survey (ASAS; Pojmanski 2002) show that the visual magnitude
of this source rose from m$_{V}\raisebox{-1mm}{$\stackrel{>}{\sim}$}$14 to m$_{V}$$\approx$12 between
Sep ~18, 2005 and Sep ~30, 2005, and then declined rapidly thereafter (see
Fig \ref{optlc})  ASAS did not detect any significant emission from
the source after around November 2005, the source having dimmed below
the limiting magnitude of ASAS 

The decline from the brightest data point ($\approx$2 2 magnitudes in
10 days, then a further $\sim$1 3 magnitudes in 46 days) suggests that
this is a nova of the 'very fast' speed class (Warner 1995, Downes
et al \ 2001)  We estimate that the time that the light curve takes to
decline 2 magnitudes below maximum observed brightness is
8$\pm$2\,days (see Section~6) 

\begin{figure}
\centering
\includegraphics[bb=30 78 453 549,clip,width=7 8cm,angle=270]{12082f10 ps}
\caption{All Sky Automated Survey V-band magnitudes of the optical counterpart 
to XMMSL1~J060636 2-694933, during outburst (late September 2005) and afterwards }
\label{optlc}
\end{figure}



\section{Discussion}

The optical spectrum, showing lines of [OIII] 4958 9\AA\, and
5006 9\AA\,, He~II at 4685 8\AA\, and a blend of the H$\alpha$ plus
[NII] at 6548 1\AA\, and 6583 4\AA\, suggests that
XMMSL1~J060636 2-694933 was a nova, observed (in Nov 2007) in the late
A$_{0}$ auroral phase  The fact that the observed [OIII] lines are not
in the more usual, optically thin 3:1 ratio, can be explained in terms
of a clumpy outflow scenario, whereby individual clumps of both
rest-frame and redward-shifted material are observed, and the
superposition of these account for the observed [OIII] ratio (note
further that density enhancements can change observed [OIII] ratios to
more like $\sim$1:1)  Clumps of material are often seen in nova ejecta
(e g  Shara et al \ 1997), and outflows of speeds around 2000\,km
s$^{-1}$ are not uncommon in novae (e g  in nova LMC 1991; Schwartz
et al \ 2001) 

XMMSL1~J060636 2-694933 was likely at its onset (in Oct 2005) a very
fast, Fe~{\sc ii} nova (Section~3 and Williams et al \ 1991; Williams
et al \ 1994)  An accurate classification now however is not possible,
so late after maximum brightness  The soft ($kT_{\rm
  eff}$$\approx$60--70\,eV) X-ray spectrum indicates that the nova was
in a super-soft source (SSS) state (Krautter 2008) during its
discovery (in July 2006), and throughout its X-ray decline (by more
than two orders of magnitude) in the observations of Sept 2006, March
2007 and June 2007   Such a state originates from nuclear burning on
the surface of the white dwarf, and measurements of the intensity,
duration, and temperature can be used to estimate the distance to the
nova and the mass of the white dwarf (e g  Balman et al \ 1998; Lanz
et al \ 2005)  Indeed, we believe (Section~4) that the white dwarf
within XMMSL1~J060636 2-694933 may be quite massive
($>$1 2$M_{\odot}$) 

As discussed earlier, classical novae are almost always discovered
optically in the early phases of their outbursts 
XMMSL1~J060636 2-694933 is very unusual therefore in that it has been
discovered first in X-rays  As such, it is useful to compare it with
XMMSL1~J070542 7-381442 (also known as V598 Pup; Read et al \ 2008),
another nova recently discovered (in X-rays) in the XMM-Newton slew
survey  With a peak $m_{V}$ of $\ltsim12$, XMMSL1~J060636 2-694933 is
not a particularly bright nova (c f  V598 Pup, which reached an
m$_{V}$ of $\raisebox{-1mm}{$\stackrel{<}{\sim}$}$4), and so it is not surprising that it went
unnoticed, only being discovered in X-rays during the later (here
291\,days after the outburst), optically thin nebular phase, when
classical novae are typically observed as soft X-ray sources  Though
this delay should be taken as a upper limit, it is long when compared
to V598 Pup ($\raisebox{-1mm}{$\stackrel{<}{\sim}$}$127 days), but may instead be more similar to the
delays of $\sim$200 days seen in V1974 Cyg (Krautter et al \ 1996),
$\sim$6 months of V382 Vel (Orio et al \ 2002), and 6$-$8 months of
V1494 Aql (Drake et al \ 2003)  In their X-ray monitoring of optical
novae in M31, Pietsch et al \ (2007) detect 11 out of 34 novae in
X-rays within a year after their optical outbursts  Seven novae are
seen to be X-ray bright, several (3$-$9) years after outburst, and
three novae showed very short X-ray outbursts, starting within
50\,days of outburst, but lasting only two to three months 
XMMSL1~J060636 2-694933 therefore is not particularly unusual 

A method to estimate the distance to the nova is to use the relation
between the absolute magnitude at maximum brightness and the time that
the light curve takes to decline 2 magnitudes below maximum
brightness, $t_{2}$ (Della Valle \& Livio 1995)  We have no
information over the 12 days between the data point of maximum
brightness and the lower limit prior to this (Fig \,\ref{optlc}), and
therefore we have no exact outburst date, nor exact apparent
magnitude at outburst   Assuming for the moment though that we have
caught the outburst exactly in the Sep ~30, 2005 observation, then we
can estimate (Sect ~5 3) $t_{2}$ to be 8$\pm$2\,days, and using this,
we can estimate (Della Valle \& Livio 1995) the absolute magnitude at
maximum brightness $M_{V}$ to be --8 7$\pm$0 6  An absolute magnitude
of $M_{V}$=--8 7 implies a peak luminosity $\sim$7 times the Eddington
luminosity for a 1\,$M_{\odot}$ white dwarf  This is quite typical of
novae 

With $A_{V}$=0 39$^{+0 05}_{-0 09}$ (90\% error), as derived (Predehl
\& Schmitt 1995) from $N_{\rm
  H}$=6 9$^{+1 0}_{-1 6}\times10^{20}$\,cm$^{-2}$ (from the highest
statistic spectral fit; the XMM-Newton ToO observation), and with
$M_{V}$=--8 7$\pm$0 6, and a peak $m_{V}$ of 12 0, we can derive a
distance to XMMSL1~J060636 2-694933 of 115$^{+43}_{-30}$\,kpc   As
discussed above however, we are unsure as to the exact outburst date
and the maximum brightness at outburst  Our assumed peak $m_{V}$ of
12 0 is almost certainly an underestimation  Although we have no
information in the 12 days prior to Sep ~30, 2005, a simple linear
extrapolation of the early October lightcurve back prior to Sep ~30,
2005 suggests that the actual peak $m_{V}$ was somewhere between 9 and
12  The corresponding distance estimates are then between 29 and
115\,kpc (with a mid-point $m_{V}$=10 5 value yielding a distance
estimate of 58\,kpc)  Many methods have been used to estimate the
distance to the LMC (e g   Kovacs 2000, Nelson et al \ 2000), but a
value of around 50\,kpc appears to be quite robust  Our distance
estimate is certainly consistent with that of the LMC, though the
errors are quite large   It does appear to be the case however, that
our distance estimate places the source far outside of our own Galaxy 
This, together with the source's position on the sky (at the eastern
edge of the LMC) and the sizable ($\sim$Galactic) X-ray hydrogen
column densities obtained from the spectral fits, suggest strongly
that XMMSL1~J060636 2-694933 lies within the LMC itself   Note further
that the (pile-up corrected) spectral model normalizations to the
initial Slew discovery data (Sect ~2) also imply an approximate
distance to XMMSL1~J060636 2-694933 of $\sim$50\,kpc 

The source had, at the time of the slew detection, an absorbed
(0 2$-$2\,keV) X-ray flux of 4 8$^{+2 7}_{-1 6}\times10^{-11}$\,ergs
cm$^{-2}$ s$^{-1}$, corresponding to a 0 2$-$2\,keV X-ray luminosity
(at 50\,kpc) of 1 4$^{+0 8}_{-0 5}\times10^{37}$\,ergs s$^{-1}$ 
Assuming instead for the moment a distance more like 100\,kpc (though
this is thought to be well beyond the LMC, e g  Kovacs 2000), then the
(0 2$-$2\,keV) X-ray luminosity of
5 7$^{+3 0}_{-1 9}\times$$10^{37}$\,erg s$^{-1}$ obtained is at the high end of the X-ray luminosities of
classical SSS-phase novae discussed e g \,in Orio et al \ (2002) and
Ness et al \ (2007)  As discussed though, we have very likely missed
the outburst peak, and as such, our more probable assumed distance of
50\,kpc gives rise to a more typical SSS-phase X-ray luminosity   The
luminosities of 7$-$8$\times$$10^{34}$\,erg s$^{-1}$, obtained during
the Swift and pointed XMM-Newton observations, are more typical of
novae at later times, when the emission can also sometimes be
described by a thermal plasma, rather than a black-body type spectrum,
or a more mixed spectrum, due to the complex structure of the ejecta
and the accretion disk (Krautter 2008, Shore 2008) 


\section{Conclusions}

A bright X-ray source, XMMSL1~J060636 2-694933, was detected in an
XMM-Newton slew on 18 July 2006 at a position where no previous X-ray
source had been seen  The XMM-Newton slew data, plus follow-up dedicated
XMM-Newton and Swift observations, plus optical imaging and
spectroscopic data acquired with the Magellan Clay telescope and 
All-Sky Automated Survey (ASAS) data were used to classify the new object
as a nova, and to examine its properties  The primary conclusions are
as follows:

  \begin{itemize}

  \item The soft X-ray spectrum indicates that the nova was in a
    super-soft source (SSS) state at its discovery in July 2007
    (XMM-Newton slew) and through its X-ray decline (by over two
    orders of magnitude) in September 2006 (XMM-Newton slew), March
    2007 (Swift) and June 2007 (XMM-Newton) 

  \item The Magellan optical spectrum (Nov 2007) of the source
    indicates that it was very likely then a nova in the late
    A$_{0}$ auroral phase 

  \item The very fast optical decline (ASAS) during the nova's onset
    (Oct 2005), indicates that the initial nova was likely of speed class
    'very fast' 

  \item The very fast speed, together with the absolute magnitude at
    maximum brightness and the X-ray absorption, give rise to a
    distance to the source far beyond our own Galaxy  The large
    distance, together with the source's position in the sky, at the
    eastern edge of the LMC, and the spectral information from the
    X-ray data, are very suggestive that the nova is situated within
    the LMC itself 

  \item Analysis of XMM-Newton slew data is continuing to provide a
    powerful means of finding new X-ray transient objects 

\end{itemize}

\begin{acknowledgements}

  The XMM-Newton project is an ESA Science Mission with instruments
  and contributions directly funded by ESA Member States and the USA
  (NASA)  The XMM-Newton project is supported by the Bundesministerium
  f\"ur Wirtschaft und Technologie/Deutsches Zentrum f\"ur Luft- und
  Raumfahrt (BMWI/DLR, FKZ 50 OX 0001), the Max-Planck Society and the
  Heidenhain-Stiftung  AMR and PE acknowledge the support of STFC
  funding, and PGJ of the Netherlands Organisation for Scientific
  Research  The ASAS project is supported by the N2030731/1328 grant
  from the MNiSzW  We thank the referee (G \,Sala) for very useful
  comments and several references that have improved the paper
  notably  We thank Kim Page for providing the white dwarf atmosphere
  model, and we thank her and Graham Wynn for useful discussions  The
  use of the spectral analysis software package \textsc{molly} written
  by Tom Marsh is also acknowledged  MM acknowledges support by a
  Miller Institute Research Fellowship during the time in which part
  of the work was completed 

\end{acknowledgements}


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•本产品支持在系统设置中进行瞳距调节 , 调节时请务必注意，最小瞳距可能会碰触鼻梁。当您佩戴头盔后，您 “显示”中进行手动调节，请注意设置使用不合适的瞳距，可能会引起视觉重影或者眼睛疲劳。 可在“设置” ► •本产品“护眼模式”经德国 TÜV Rheinland 低蓝光认证，通过软件算法降低三色通道中的蓝光量，来达到保护 “护眼” “色彩调节” 眼睛的作用，该模式下画面颜色偏黄，您可根据个人喜好在“设置” 中激活或关闭此功能。 ““显示” ► ► ► 包装内含： VR 头盔 / 手柄 × 2 / 1 5V AA 碱性干电池 × 4/ 眼镜支架 / 遮光鼻托 / 手柄挂绳 × 2 / USB-C 电源适配器 / USB-Cto C 2 0 数据线 / 快速指南 / 用户指南 / 安全与质保指南使用前注意事项 •本产品在开阔的室內环境使用体验最佳，建议至少预留 2×2 米 的空间。使用前请确认身体没有不适且周围环 境安全，特别是佩戴头盔在室内行走移动时，要尽量避免发生意外。 •不建议 12 岁及以下儿童使用本产品，建议将头盔、手柄和配件置于儿童够不到的位置，13 岁以上青少年须在 成人监护下使用，以免发生意外。 •本产品无近视调节功能，近视用户请佩戴眼镜使用并尽量避免近视眼镜被头盔的光学镜片磨伤或刮伤。建议在 使用和收纳时注意防护光学镜片，避免尖锐物体划伤镜片，擦拭清洁时请使用柔软的眼镜布，否则可能划伤镜片， 影响视觉效果。 •长时间使用可能引发轻微的昡晕或者眼疲劳，建议使用 30 分钟后适当休息，可通过眼保健操或观看远处物体缓 解眼疲劳。如果您的身体感到任何不适，请立即停止使用。如果不适持续，请咨询医生。 •当头盔镜片被阳光或紫外线照射时（尤其在户外、阳台、窗台及汽车内存放时），可能导致屏幕出现永久性黄斑。 请尽量避免该情况发生，此种屏幕损坏不在产品的质保范围内。 *本产品最终外观及功能以实物为准，部分地区包装内含物品有所差异，本说明仅供参考。 02 CN
六自由度 VR 体验 本产品可以追踪头盔和手柄前、后、左、右、上、下和旋转的运动状态，您在现实中的肢体运动会实时反映在虚 拟世界中。 由于没有任何线缆的束缚，您在虚拟世界自由探索时请确保游玩区域的安全。 1  建议准备一个整洁安全的体验空间：至少 2×2 米；保持房间明亮，避免在只有单色的墙或大面积玻璃、镜子类 反射物以及许多移动画面和物体的空间中使用。 2  撕下 VR 头盔前端摄像头上的保护膜，并佩戴手柄挂绳。 3  根据开机后的画面提示进行游玩区域的设定。 ❶ 安装电池 按箭头方向拔出电池盖侧边的绝缘纸 快速引导 提示：本产品虚拟的安全区提醒功能，不能完全保证您在设定好的游戏区域中的安全，请时刻注意周围的安全情况。 提示：建议使用 1 5V AA 碱性电池。 按照图示拨动电池盖拨钮打开电池盖更换电池。 03 CN
❷ 手柄开机 ❸ 头盔开机 ❹ 佩戴头盔，调节至清晰舒适的位置 首次开机：拔出绝缘纸，手柄自动开机（蓝灯闪烁） 非首次开机：短按手柄 Home 键开机（蓝灯闪烁） 长按头盔电源键 2 秒（蓝灯常亮） 调节旋钮转动绑带，使后脑垫套在头上，微调绑带长度及佩戴位置至视野清晰 04 提示：近视用户请佩戴眼镜或镜片插件使用，本产品不具备近视调节功能。 CN
❺ 微调顶绑带 微调顶绑带使其受力以减少额头压力 ❻ 瞳 距 调 节 在系统设置：“设置” ► “显示”界面中进行瞳距调节，点击“+”或“-”按钮可微调瞳距直至画面清晰 64mm 请勿 强行 掰动镜 筒，以 免造 成损坏 ！ 请注 意设 置使用 不合适 的瞳 距，可 能 会引起 视 觉重影 或 者眼睛 疲 劳。准 确 的瞳距 设 置有助 于 获得清 晰 的图像 并 减少眼睛 疲劳。 05 CN
产品部件详情说明 头盔状态指示灯 蓝灯常亮：开机进行中或工作状态 黄灯常亮：充电中，电量低于 98% 红灯常亮：充电中，电量低于 20% 绿灯常亮：充电完毕，电量大于 98% 或 充满 蓝灯闪烁：关机进行中 红灯闪烁：电量低于 20% 指示灯熄灭：休眠或关机 06 ① 电源键 开机：长按 2 秒 关机：长按 5 秒 复位：长按 10 秒 开机时，短按休眠 ② ③ ④ ⑤ 状态指示灯 贴脸泡棉 音量键 彩色透视摄像头 使用时请勿遮挡 ⑥ ⑦ ⑧ 顶部绑带 可拆卸 绑带旋钮 环境追踪摄像头 使用时请勿遮挡 ⑨ ⑩ ⑪ USB-C 接口 左 / 右喇叭 距离传感器 佩戴头盔后，系统自动唤醒 摘下头盔后，系统自动休眠 ⑫ ⑬ 眼球追踪摄像头 此功能仅 Pro 版支持 使用时请勿遮挡 面部追踪摄像头 此功能仅 Pro 版支持 使用时请勿遮挡 CN
手柄状态指示灯 熄灭：已连接或者关机 蓝灯常亮：固件升级模式 蓝灯闪烁：连接中 红蓝灯交替慢速闪烁：等待配对 ① ② 摇杆 菜单键 ③ Home 键 开机 : 短按关机 : 长按 6 秒退出应用 : 短按屏幕中心校正 : 长按 1 秒④ ⑤ ⑥ ⑦ 状态指示灯 抓握键 截屏键 扳机键 ⑧ ⑨ 电池盒 打开：拨动拨钮，电池盒弹出 安装：按压直至自动锁紧 追踪光环 使用时请勿遮挡 注：手柄挂绳可按图示将粗绳穿过细绳并锁紧在手柄尾端 07 CN
手柄硬件复位 如果手柄出现按 Home 键和任何按键均无反应或者头盔中虚拟手柄卡死不动的问题可拆装电池重新启动手柄。 近视用户配戴 本设备不具备近视调节功能，头盔可支持佩戴镜框宽度小于 150mm 的大多数标准眼镜。 操作说明 头控模式 未连接手柄的情况下，您可通过转动头部光标及点击头盔音量加减按键进行操作。 切换主控手柄射线 在主控菜单下，短按对应手柄的扳机键可以切换主控手柄的射线。 屏幕中心校正 戴着头盔直视前方，按住手柄 Home 键（或头控模式下头盔上的音量减键）1 秒以上，进行屏幕中心的校正将菜 单拉到当前视野朝向位置。 断开手柄 长按手柄 Home 键直至手柄状态指示灯红灯亮起并伴随振动产生时即可松手，此时手柄关机并断开与头盔的连接。 您无需刻意进行手柄关机操作，在以下状态下手柄会自动关机省电： •头盔进入深度休眠时（摘下头盔后一段时间） •头盔手柄管理界面解绑手柄时 •头盔关机时 添加新手柄 如需添加新手柄（头盔最多可同时连接一对手柄，即左右手柄各一只），或解绑手柄后再次连接 , 可进入“设置” “手 柄”，点击“配对”，同时按住手柄 Home 键和扳机键直至手柄状态指示灯红蓝交替闪烁时即可松开，然后根据 头盔画面提示操作。 ► 休眠 / 唤醒 方式一：摘下头盔一段时间后，系统自动休眠；戴上头盔时，系统自动唤醒。 方式二：短按头盔电源键也可以进行休眠或唤醒操作。 硬件复位 头盔硬件复位 如果头盔出现短按头盔电源键没有反应或头盔的画面卡死等问题，可以长按头盔电源键 10 秒以上重新启动头盔。 08 CN
安装眼镜支架 安装遮光鼻托 如您存在眼镜摩擦光学镜片或者压迫鼻梁的问题，请按照图示安装眼镜支架以增加间隔空间。 您可根据佩戴的舒适度选择是否安装。 如您感觉鼻子处漏光影响体验，请按照图示安装遮光鼻托配件。 由于眼睛空间密闭可能加剧起雾及出汗问题，您可根据喜好选择是否安装。 ❶ 摘下贴脸泡棉 ❷ 将眼镜支架按照图示安装在产品上 ❸ 将贴脸泡棉按照图示安装眼镜支架上 ❶ 摘下贴脸泡棉 ❸ 安装贴脸泡棉❷ 将遮光鼻托按照图示方式安装在贴脸泡棉上 注：按照图示拆卸眼镜支架 09 CN
更换贴脸泡棉 贴脸泡棉多次清洁和长时间使用后会变色和质地变软，您可酌情更换新泡棉。 更换顶绑带 摘下贴脸泡棉 ❸ 安装贴脸泡棉 按照图示捏住顶绑带金属扣，往下压到底然后抽出 ❷ •购买优质热门应用 •畅 聊 社 区， 与 众 多 PICO 玩 家 一起探索 VR 世界 •管理设备更便捷 •参与丰富互动活动 •更多精彩内容等你来发现 ❶ 微 信公 众 号：PICO VR抖音：PICO官 方 旗 舰 店哔 哩 哔 哩：PICO-VR官 方微 博：PICO-VR ❶ ❷ 10 CN
In The Box: VR Headset / 2 Controllers / 4 1 5V AA Alkaline Batteries / Glasses Spacer / Nose Pad / 2 Controller Lan- yards / USB-C Power Adapter / USB-C to C 2 0 Data Cable / Quick Guide / User Guide / Safety and WarrantyGuide Important Health & Safety Notes • This product is designed and intended to be used in an open and safe indoor area, free of anytripping or slipping hazards  To avoid accidents, remain conscious to the potential confines ofyour physical area and respect the boundary of your virtual area whenever you see it  Be sure towear the lanyards when using the Controllers  Make sure that there is enough space around yourhead and body (at least 2 meters by 2 meters) to stretch your arms to avoid damage or injury toyourself, others, and your surroundings  • This product is not recommended for children aged 12 and under  It is recommended to keep headsets,controllers and accessories out of the reach of children  Teenagers aged 13 and over must use it underadult supervision to avoid accidents  • This product is designed to accommodate most prescription glasses  Make sure to wear the VR Headsetin a manner in which the VR Headset lenses do not rub or impair your prescription lenses  • Prolonged use may cause dizziness or eye fatigue  It is recommended to take a break every 30 minutes Try relieving your eyestrain by looking at distant objects  If you feel any discomfort, stop using the prod- uct immediately  If the discomfort persists, seek medical advice • Do not expose the optical lenses to direct sunlight or other strong light sources  Exposure to directsunlight may cause permanent yellow spot damage on the screen  Screen damage caused by sunlightexposure or other strong sources of light is not covered by the warranty  • This product supports interpupillary distance (IPD) adjustment in system settings  When adjusting,please be aware that with the minimum IPD, it may touch the bridge of the nose  You can adjust the IPDaccording to your actual interpupillary distance in "Settings"►"Display"  Please note that using inap- propriate IPD may increase the risk of discomfort  • This product has an “Eye Protection Mode”, certified by TÜV Rheinland (Germany), which can protectyour eyes by reducing blue light in the three color channels using software algorithms  The screen ap- pears yellowish in this mode and you can turn this feature on/off in "Settings"►"Display"►"Color"►“- Eye Protection”  • Protect optical lenses during use and storage to prevent damage, such as scratches or exposure tostrong light or direct sunlight  * Product and packaging are updated regularly, and the functions and contents of the standalone headset may be upgraded in the future Therefore, the content, appearance and functionality listed in this manual and product packaging are subject to change and may notreflect the final product  These instructions are for reference only  * Carefully read this user guide before using the product and share this information with any other users, as it contains important safetyinformation  Keep the user guide as reference for the future  11 EN
6 Degrees of Freedom VR The device can track your translational and rotational movements in all directions (up/down, left/right,forward/backward, pitch, roll, and yaw)  Your movements in the real world will be captured and translatedto what you see in the virtual world when using the appropriate content  Ensure a safe environment before you start your VR experience  1  Clear a safe indoor area of at least 2 meters by 2 meters  Keep the room bright, avoid spaces with main- ly single-colored walls, glass, mirrors, moving pictures or other similar objects  2  Remove the protective film that covers the headset front cameras  Wear the lanyards connected to theControllers  3  Set up your environment by following instructions on the VR Headset screen  Install Batteries ❶Pull the tab to remove the insulating paper  Quick Guide 2 m 2m This product can not guarantee your safety with guardian system, you will need to always pay attention to the surrounding safety  * Note: 1 5V AA alkaline batteries should be used
Context 3: consumption influences mercury: Topics by WorldWideScience org
Sample records for consumption influences mercury
Epidemiologic confirmation that fruit consumption influences mercury exposure in riparian communities in the Brazilian Amazon
Sousa Passos, Carlos Jose; Mergler, Donna; Fillion, Myriam; Lemire, Melanie; Mertens, Frederic; Guimaraes, Jean Remy Davee; Philibert, Aline
Since deforestation has recently been associated with increased mercury load in the Amazon, the problem of mercury exposure is now much more widespread than initially thought  A previous exploratory study suggested that fruit consumption may reduce mercury exposure  The objectives of the study were to determine the effects of fruit consumption on the relation between fish consumption and bioindicators of mercury (Hg) exposure in Amazonian fish-eating communities  A cross-sectional dietary survey based on a 7-day recall of fish and fruit consumption frequency was conducted within 13 riparian communities from the Tapajos River, Brazilian Amazon  Hair samples were collected from 449 persons, and blood samples were collected from a subset of 225, for total and inorganic mercury determination by atomic absorption spectrometry  On average, participants consumed 6 6 fish meals/week and ate 11 fruits/week  The average blood Hg (BHg) was 57 1Â±36 3 Î¼g/L (median: 55 1 Î¼g/L), and the average hair-Hg (HHg) was 16 8Â±10 3 Î¼g/g (median: 15 7 Î¼g/g)  There was a positive relation between fish consumption and BHg (r=0 48; P 2 =36 0%) and HHg levels (fish: Î²=1 2, P 2 =21 0%)  ANCOVA models showed that for the same number of fish meals, persons consuming fruits more frequently had significantly lower blood and HHg concentrations  For low fruit consumers, each fish meal contributed 9 8 Î¼g/L Hg increase in blood compared to only 3 3 Î¼g/L Hg increase for the high fruit consumers  In conclusion, fruit consumption may provide a protective effect for Hg exposure in Amazonian riparians  Prevention strategies that seek to maintain fish consumption while reducing Hg exposure in fish-eating communities should be pursued
Influence of mercury bioaccessibility on exposure assessment associated with consumption of cooked predatory fish in Spain 
Torres-Escribano, Silvia; Ruiz, Antonio; Barrios, Laura; VÃ©lez, Dinoraz; Montoro, Rosa
Predatory fish tend to accumulate high levels of mercury (Hg)  Food safety assessment of these fish has been carried out on the raw product  However, the evaluation of the risk from Hg concentrations in raw fish might be modified if cooking and bioaccessibility (the contaminant fraction that solubilises from its matrix during gastrointestinal digestion and becomes available for intestinal absorption) were taken into account  Data on Hg bioaccessibility in raw predatory fish sold in Spain are scarce and no research on Hg bioaccessibility in cooked fish is available  The aim of the present study was to evaluate Hg bioaccessibility in various kinds of cooked predatory fish sold in Spain to estimate their health risk  Both Hg and bioaccessible Hg concentrations were analysed in raw and cooked fish (swordfish, tope shark, bonito and tuna)  There were no changes in Hg concentrations during cooking  However, Hg bioaccessibility decreased significantly after cooking (42 Â± 26% in raw fish and 26 Â± 16% in cooked fish), thus reducing in swordfish and tope shark the Hg concentration to which the human organism would be exposed  In future, cooking and bioaccessibility should be considered in risk assessment of Hg concentrations in predatory fish  Copyright Â© 2011 Society of Chemical Industry 
Intake of mercury through fish consumption
Sarmani, S B ; Kiprawi, A Z ; Ismail, R B ; Hassan, R B ; Wood, A K ; Rahman, S A 
Fish has been known as a source of non-occupational mercury exposure to fish consuming population groups, and this is shown by the high hair mercury levels  In this study, hair samples collected from fishermen and their families, and commercial marine fishes were analyzed for mercury and methylmercury by neutron activation and gas chromatography  The results showed a correlation between hair mercury levels and fish consumption patterns  The levels of mercury found in this study were similar to those reported by other workers for fish consuming population groups worldwide  (author)
Fish consumption limit for mercury compounds
Abbas Esmaili-Sari
Full Text Available Background and objectives: Methyl mercury can carry out harmful effects on the reproductive, respiratory, and nervous system of human  Moreover, mercury is known as the most toxic heavy metal in nature  Fish and seafood consumption is the major MeHg exposure route for human  The present study tries to cover researches which have been conducted on mercury levels in 21 species of fish from Persian Gulf, Caspian Sea and Anzali Wetland during the past 6 years, and in addition to stating mercury level, it provides recommendations about the restriction of monthly fish consumption for each species separately  Material and methods: Fish samples were transferred to the laboratory and stored in refrigerator under -20oC until they were dissected  Afterwards, the muscle tissues were separated and dried  The dried samples were ground and changed into a homogenous powder and then the mercury concentration rate has been determined by advanced mercury analyzer, model 254  Results: In general, mercury contamination in fishes caught from Anzali Wetland was much more than fishes from Caspian Sea  Also, from among all studied fishes, oriental sole (Euryglossa orientalis, caught from Persian Gulf, allocated the most mercury level to itself with the rate of 5 61ml per kg , therefore, it exercises a severe consumption restriction for pregnant women and vulnerable groups  Conclusion: Based on the calculations, about 50% of fishes, mostly with short food chain, can be easily consumed during the year  However, with regard to Oriental sole (Euryglossa orientalis and shark (Carcharhinus dussumieri, caught from Persian Gulf, special consideration should be taken in their consumption  On the other hand, careful planning should be made for the high rate of fish consumption among fishing community 
Hair Mercury Concentrations and Fish Consumption Patterns in Florida Residents
Adam M  Schaefer
Full Text Available Mercury exposure through the consumption of fish and shellfish represents a significant public health concern in the United States  Recent research has demonstrated higher seafood consumption and subsequent increased risk of methylmercury exposure among subpopulations living in coastal areas  The identification of high concentrations of total mercury in blood and skin among resident Atlantic bottlenose dolphins (Tursiops truncatus in the Indian River Lagoon (IRL, a coastal estuary in Florida, alerted us to a potential public health hazard in the contiguous human population  Therefore, we analyzed hair mercury concentrations of residents living along the IRL and ascertained their sources and patterns of seafood consumption  The total mean mercury concentration for 135 residents was 1 53 Â± 1 89 Âµg/g  The concentration of hair mercury among males (2 02 Â± 2 38 Âµg/g was significantly higher than that for females (0 96 Â± 0 74 Âµg/g (p < 0 01  Log transformed hair mercury concentration was significantly associated with the frequency of total seafood consumption (p < 0 01  Individuals who reported consuming seafood once a day or more were 3 71 (95% CI 0 84â€“16 38 times more likely to have a total hair mercury concentration over 1 0 Âµg/g, which corresponds approximately to the U S  EPA reference dose, compared to those who consumed seafood once a week or less  Hair mercury concentration was also significantly higher among individuals who obtained all or most of their seafood from local recreational sources (p < 0 01  The elevated human mercury concentrations mirror the elevated concentrations observed in resident dolphins in the same geographical region  The current study is one of the first to apply the concept of a sentinel animal to a contiguous human population 
Fish consumption and bioindicators of inorganic mercury exposure
Sousa Passos, Carlos Jose; Mergler, Donna; Lemire, Melanie; Fillion, Myriam; Guimaraes, Jean Remy Davee
Background: The direct and close relationship between fish consumption and blood and hair mercury (Hg) levels is well known, but the influence of fish consumption on inorganic mercury in blood (B-IHg) and in urine (U-Hg) is unclear  Objective: Examine the relationship between fish consumption, total, inorganic and organic blood Hg levels and urinary Hg concentration  Methods: A cross-sectional study was carried out on 171 persons from 7 riparian communities on the Tapajos River (Brazilian Amazon), with no history of inorganic Hg exposure from occupation or dental amalgams



ground_truth: 4.5x10^8 cm.

prompt_front: Now, answer the following question based on the text below, only give me the answer and do not output any other words.

Question: What may happen if the VR headset lenses are exposed to sunlight or strong light?

Read the following text and answer briefly.

Context 2: Slide the toggle according to arrow direction toopen the battery case  12 EN
Power on the Controller ❷ First Start: The Controller will start automaticallyafter removing the insulating paper  Others: Short press the Home button for 1second until the status indicator flashes blue Power on the VR Headset ❸ Long press the Power button for 2 seconds untilthe status indicator turns blue Wear Your Headset for a Comfortable Fit and View ❹ Adjust the strap dial to turn the strap so that the back of your head rests on the padding  Fine-tune thelength and position of the strap to give a clear view  * Note: You can use this product with prescription glasses or lenses insert  13 EN
Fine-tune the Top Strap ❺ Fine-tune the head strap to reduce pressure on the forehead  Interpupillary Distance (IPD) Adjustment ❻ In System Setting, go to “Setting” ► “Display” to adjust IPD, tap “+” or “-” button to slightly adjust IPDuntil the picture is clear  14 64mm Please note that inappropriate IPD setting may cause ghosting or eyestrain Accurate IPD setting helps you get a clear imaging and ease eyestrain  EN
Product Details VR Headset Status Indicator Legend Blue: Powered on with battery over 20% Yellow: Charging: Battery is less than 98% Red: Charging: Battery is less than 20% Green: Charging: Battery is more than 98% or charge complete Blue flashing: Shutting down Red flashing: Battery is less than 20% Off: Sleeping or Powered off Power Power on: Long press for 2 seconds Power off: Long press for 5 seconds Hardware reset: Long press for 10 seconds Short press to enter sleep or wake up Status Indicator Face Cushion Volume ① ② ③ ④ ⑤ ⑥ ⑦ ⑧ RGB See Through Camera Do not block during use  Top Strap Removable Strap Dial Tracking Cameras Do not block during use  ⑨ ⑩ ⑪ USB-C Interface Left/Right Speaker Proximity Sensor The system wakes upwhen the VR headset isput on, sleeps when VRheadset is taken off  ⑫ ⑬ Eye Tracking Cameras Pro version only  Do not block during use  Face Tracking Camera Pro version only  Do not block during use  15 EN
Controller Status Indicator Legend Off: Connected or Powered off Blue: Firmware updating in progress Blue flashing: Searching for connection Red and blue flashing alternately: Pairing in progress 16 Joystick Menu ③ ① ② Home Power on: Short pressPower off: Long press for 6 secondsReturn home screen: Short pressScreen recentering: Press for 1 secondStatus Indicator Grip Capture Trigger ④ ⑤ ⑥ ⑦ ⑧ ⑨ Battery Case Open: Slide down the toggle andpop up the battery case  Lock: Push the battery case to lock  Tracking Ring Do not block during use  * Note: Pass the Controller Lanyardthrough the string as shown andlock at the end of the Controller EN
Operating Instructions Headset Control Mode If the Controller is not connected, you can interact with the home screen by moving your head to directthe crosshairs over your intended selection and clicking the Volume Up/Down button on the VR Headset  Switch the pointer of the master Controller In the home screen, short press the Trigger of the corresponding Controller to switch the pointer of themaster Controller  Screen re-centering Wear the VR Headset and look straight ahead, press and hold the Home button of the Controller or VRHeadset ( or the Volume Down button of the VR Headset in head control mode) for more than 1 second tore-center the screen  Disconnect the Controller Press and hold the Home button until the status indicator turns red and the Controller vibrates Controllers will automatically shut down to save power in the following cases:When the VR Headset enters deep sleep (a while after the VR Headset is taken off)When the Controller is unpairedWhen the VR Headset is powered off Add a new Controller If you need to add a new Controller (the VR Headset can only connect one left Controller and one rightController) or reconnect with an unpaired Controller  Go to “Settings” ► “Controller”, click on “Pair” Press and hold the Home button and the Trigger of the Controller at the same time until the red and bluelights of the Controller flashing alternately, and then follow the instructions on the VR Headset screen  Sleep / Wake up Option 1 (Proximity Sensor) Take off VR Headset for automatic sleeping: wear the VR Headset for automat- ic waking up  Option 2 (POWER Button) Press the Power button of the VR Headset for manual sleeping or waking up  Hardware reset VR Headset reset If the visual in the VR Headset freezes, or the VR Headset does not respond after short press the Powerbutton, you can press the Power button of the VR Headset for more than 10 seconds to reboot the VRHeadset  Controller reset If the virtual Controller, the Home button or any buttons of the Controller doesn\'t respond, remove andreinstall the battery case to restart the Controller  The VR Headset Adjustment This device has no myopia adjustment function  The VR Headset allows wearing most standard glasseswith a frame width of less than 150mm  to install Glasses Spacer to increase the space  You can install or not according to your situation  17 EN
Install Glasses Spacer Install Nose Pad If you have glasses collision with headset lens or pressure on the bridge of nose, please follow the pictureto install Glasses Spacer to increase the space  You can install or not according to your situation  If you feel light leaking from your nose, please follow the picture to install Nose Pad to block the light You can consider having it installed at your own discretion  Disassemble the Face Cushion  Install the Glasses Spacer on the Headset  ❸ ❶ ❷ Install the Face Cushion on the Glasses Spacer  Disassemble the Face Cushion  Install the Nose Pad on the Face Cushion  ❶ ❷ Install the Face Cushion on the Headset  ❸ * Note: Disassemble the Glasses Spacer 18 EN
Replace Face Cushion The Face Cushion will have the following phenomena such as color change, surface fluff, soft texture afterlong-term use and repeated cleaning  You can replace a new Face Cushion as needed  Replace Top Strap ❶ ❷ Disassemble the Face Cushion  Pinch the metal buckle of the top strap asshown, press it down and pull it out Install the Face Cushion on  ❸ ❷ ❶ • Purchase high-quality and trending apps • Join PICO Community and explore the VR worldwith other PICO players• Manage your device with ease • Engage in diverse and interactive activities • More exciting features waiting for you 19 EN
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Context 3:  During the rising water season in 2004, participants responded to a dietary survey, based on a seven-day recall of fish and fruit consumption frequency, and socio-demographic information was recorded  Blood and urine samples were collected  Total, organic and inorganic Hg in blood as well as U-Hg were determined by Atomic Absorption Spectrometry  Results: On average, participants consumed 7 4 fish meals/week and 8 8 fruits/week  Blood total Hg averaged 38 6 Â± 21 7 Î¼g/L, and the average percentage of B-IHg was 13 8%  Average organic Hg (MeHg) was 33 6 Â± 19 4 Î¼g/L, B-IHg was 5 0 Â± 2 6 Î¼g/L, while average U-Hg was 7 5 Â± 6 9 Î¼g/L, with 19 9% of participants presenting U-Hg levels above 10 Î¼g/L  B-IHg was highly significantly related to the number of meals of carnivorous fish, but no relation was observed with non-carnivorous fish; it was negatively related to fruit consumption, increased with age, was higher among those who were born in the Tapajos region, and varied with community  U-Hg was also significantly related to carnivorous but not non-carnivorous fish consumption, showed a tendency towards a negative relation with fruit consumption, was higher among men compared to women and higher among those born in the region  U-Hg was strongly related to I-Hg, blood methyl Hg (B-MeHg) and blood total Hg (B-THg)  The Odds Ratio (OR) for U-Hg above 10 Î¼g/L for those who ate > 4 carnivorous fish
Methyl mercury exposure in Swedish women with high fish consumption
Bjoernberg, Karolin Ask [Division of Metals and Health, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm (Sweden); Vahter, Marie [Division of Metals and Health, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm (Sweden); Grawe, Kierstin Petersson [Toxicology Division, National Food Administration, Box 622, SE-751 26 Uppsala (Sweden); Berglund, Marika [Division of Metals and Health, Institute of Environmental Medicine, Karolinska Institutet, Box 210, SE-171 77, Stockholm (Sweden)]  E-mail: Marika Berglund@imm ki se
We studied the exposure to methyl mercury (MeHg) in 127 Swedish women of childbearing age with high consumption of various types of fish, using total mercury (T-Hg) in hair and MeHg in blood as biomarkers  Fish consumption was assessed using a food frequency questionnaire (FFQ), including detailed information about consumption of different fish species, reflecting average intake during 1 year  We also determined inorganic mercury (I-Hg) in blood, and selenium (Se) in serum  The average total fish consumption, as reported in the food frequency questionnaire, was approximately 4 times/week (range 1 6-19 times/week)  Fish species potentially high in MeHg, included in the Swedish dietary advisories, was consumed by 79% of the women  About 10% consumed such species more than once a week, i e , more than what is recommended  Other fish species potentially high in MeHg, not included in the Swedish dietary advisories, was consumed by 54% of the women  Eleven percent never consumed fish species potentially high in MeHg  T-Hg in hair (median 0 70 mg/kg; range 0 08-6 6 mg/kg) was associated with MeHg in blood (median 1 7 {mu}g/L; range 0 30-14 {mu}g/L; r {sub s}=0 78; p<0 001)  Hair T-Hg, blood MeHg and serum Se (median 70 {mu}g/L; range 46-154 {mu}g/L) increased with increasing total fish consumption (r {sub s}=0 32; p<0 001, r {sub s}=0 37; p<0 001 and r {sub s}=0 35; p=0 002, respectively)  I-Hg in blood (median 0 24 {mu}g/L; range 0 01-1 6 {mu}g/L) increased with increasing number of dental amalgam fillings  We found no statistical significant associations between the various mercury species measured and the Se concentration in serum  Hair mercury levels exceeded the levels corresponding to the EPA reference dose (RfD) of 0 1 {mu}g MeHg/kg b w  per day in 20% of the women  Thus, there seems to be no margin of safety for neurodevelopmental effects in fetus, for women with high fish consumption unless they decrease their intake of certain fish species 
Bjoernberg, Karolin Ask; Vahter, Marie; Grawe, Kierstin Petersson; Berglund, Marika
We studied the exposure to methyl mercury (MeHg) in 127 Swedish women of childbearing age with high consumption of various types of fish, using total mercury (T-Hg) in hair and MeHg in blood as biomarkers  Fish consumption was assessed using a food frequency questionnaire (FFQ), including detailed information about consumption of different fish species, reflecting average intake during 1 year  We also determined inorganic mercury (I-Hg) in blood, and selenium (Se) in serum  The average total fish consumption, as reported in the food frequency questionnaire, was approximately 4 times/week (range 1 6-19 times/week)  Fish species potentially high in MeHg, included in the Swedish dietary advisories, was consumed by 79% of the women  About 10% consumed such species more than once a week, i e , more than what is recommended  Other fish species potentially high in MeHg, not included in the Swedish dietary advisories, was consumed by 54% of the women  Eleven percent never consumed fish species potentially high in MeHg  T-Hg in hair (median 0 70 mg/kg; range 0 08-6 6 mg/kg) was associated with MeHg in blood (median 1 7 Î¼g/L; range 0 30-14 Î¼g/L; r s =0 78; p s =0 32; p s =0 37; p s =0 35; p=0 002, respectively)  I-Hg in blood (median 0 24 Î¼g/L; range 0 01-1 6 Î¼g/L) increased with increasing number of dental amalgam fillings  We found no statistical significant associations between the various mercury species measured and the Se concentration in serum  Hair mercury levels exceeded the levels corresponding to the EPA reference dose (RfD) of 0 1 Î¼g MeHg/kg b w  per day in 20% of the women  Thus, there seems to be no margin of safety for neurodevelopmental effects in fetus, for women with high fish consumption unless they decrease their intake of certain fish species
Fish Consumption and Mercury Exposure among Louisiana Recreational Anglers
Lincoln, Rebecca A; Shine, James P; Chesney, Edward J
Background: Methylmercury (MeHg) exposure assessments among average fish consumers in the U S  may underestimate exposures among U S



ground_truth: Exposure to sunlight or strong light may cause permanent yellow spot damage on the screen.

prompt_front: Now, answer the following question based on the text below, only give me the answer and do not output any other words.

Question: What was the conclusion of the study?

Read the following text and answer briefly.

Context 3:  subpopulations with high intakes of regionally specific fish  Objectives: We examined relationships between fish consumption, estimated mercury (Hg) intake      , and measured Hg exposure among one such potentially highly-exposed group, recreational anglers in Louisiana USA  Methods: We surveyed 534 anglers in 2006 using interviews at boat launches and fishing tournaments combined with an internet-based survey method  Hair samples from 402 of these anglers were       collected and analyzed for total Hg  Questionnaires provided information on species-specific fish consumption over 3 months prior to the survey  Results: Anglers' median hair-Hg concentration was 0 81 Âµg/g (n=398; range: 0 02-10 7 Âµg/g), with 40% of participants above 1 Âµg/g, the level that approximately   
Umbilical cord blood and placental mercury, selenium and selenoprotein expression in relation to maternal fish consumption
Gilman, Christy L ; Soon, Reni; Sauvage, Lynnae; Ralston, Nicholas V C ; Berry, Marla J 
Seafood is an important source of nutrients for fetal neurodevelopment  Most individuals are exposed to the toxic element mercury through seafood  Due to the neurotoxic effects of mercury, United States government agencies recommend no more than 340 g (12 oz) per week of seafood consumption during pregnancy  However, recent studies have shown that selenium, also abundant in seafood, can have protective effects against mercury toxicity  In this study, we analyzed mercury and selenium levels an   
Factors that negatively influence consumption of traditionally    
Factors that negatively influence consumption of traditionally fermented milk     in various countries of sub-Saharan Africa and a number of health benefits to human     influence consumption of Mursik, a traditionally fermented milk product fromÂ    
Mercury exposure as a function of fish consumption in two Asian communities in coastal Virginia, USA 
Xu, Xiaoyu; Newman, Michael C
Fish consumption and associated mercury exposure were explored for two Asian-dominated church communities in coastal Virginia and compared with that of two non-Asian church communities  Seafood-consumption rates for the Chinese (36 9Â g/person/day) and Vietnamese (52 7Â g/person/day) church communities were greater than the general United States fish-consumption rate (12 8Â g/person/day)  Correspondingly, hair mercury concentrations for people from the Chinese (0 52Â Âµg/g) and the Vietnamese church (1 46Â Âµg/g) were greater than the overall level for United States women (0 20Â Âµg/g) but lower than the published World Health Organization exposure threshold (14Â Âµg/g)  A conventional regression model indicated a positive relationship between seafood consumption rates and hair mercury concentrations suggesting the importance of mercury exposure through seafood consumption  The annual-average daily methylmercury intake rate for the studied communities calculated by Monte Carlo simulations followed the sequence: Vietnamese communityÂ >Â Chinese communityÂ >Â non-Asian communities  Regardless, their daily methylmercury intake rates were all lower than the United States Environmental Protection Agency reference dose of 0 1Â Âµg/kg body weight-day  In conclusion, fish-consumption patterns differed among communities, which resulted in different levels of mercury exposure  The greater seafood and mercury ingestion rates of studied Asian groups compared with non-Asian groups suggest the need for specific seafood consumption advice for ethnic communities in the United States  Otherwise the health benefits from fish consumption could be perceived as trivial compared with the ill-defined risk of mercury exposure 
Feather growth influences blood mercury level of young songbirds 
Condon, Anne M; Cristol, Daniel A
Dynamics of mercury in feathers and blood of free-living songbirds is poorly understood  Nestling eastern bluebirds (Sialia sialis) living along the mercury-contaminated South River (Virginia, USA) had blood mercury levels an order of magnitude lower than their parents (nestling: 0 09 +/- 0 06 mg/kg [mean +/- standard deviation], n = 156; adult: 1 21 +/- 0 57 mg/kg, n = 86)  To test whether this low blood mercury was the result of mercury sequestration in rapidly growing feathers, we repeatedly sampled free-living juveniles throughout the period of feather growth and molt  Mean blood mercury concentrations increased to 0 52 +/- 0 36 mg/kg (n = 44) after the completion of feather growth  Some individuals had reached adult blood mercury levels within three months of leaving the nest, but levels dropped to 0 20 +/- 0 09 mg/kg (n = 11) once the autumn molt had begun  Most studies of mercury contamination in juvenile birds have focused on recently hatched young with thousands of rapidly growing feathers  However, the highest risk period for mercury intoxication in young birds may be during the vulnerable period after fledging, when feathers no longer serve as a buffer against dietary mercury  We found that nestling blood mercury levels were not indicative of the extent of contamination because a large portion of the ingested mercury ended up in feathers  The present study demonstrates unequivocally that in songbirds blood mercury level is influenced strongly by the growth and molt of feathers 
High mercury seafood consumption associated with fatigue at specialty medical clinics on Long Island, NY
Shivam Kothari
Full Text Available We investigated the association between seafood consumption and symptoms related to potential mercury toxicity in patients presenting to specialty medical clinics at Stony Brook Medical Center on Long Island, New York  We surveyed 118 patients from Aprilâ€“August 2012 about their seafood consumption patterns, specifically how frequently they were eating each type of fish, to assess mercury exposure  We also asked about symptoms associated with mercury toxicity including depression, fatigue, balance difficulties, or tingling around the mouth  Of the 118 adults surveyed, 14 consumed high mercury seafood (tuna steak, marlin, swordfish, or shark at least weekly  This group was more likely to suffer from fatigue than other patients (pÂ =Â 0 02  Logistic regression confirmed this association of fatigue with frequent high mercury fish consumption in both unadjusted analysis (ORÂ =Â 5 53; 95% CI: 1 40â€“21 90 and analysis adjusted for age, race, sex, income, and clinic type (ORÂ =Â 7 89; 95% CI: 1 63â€“38 15  No associations were observed between fish intake and depression, balance difficulties, or tingling around the mouth  Findings suggest that fatigue may be associated with eating high mercury fish but sample size is small  Larg



ground_truth: The conclusion was that fruit consumption may provide a protective effect for mercury exposure in Amazonian riparians.