bluuebunny/crossref_metadata_2025 huggingface dataset:
ZnFe2O4‐Decorated Mesoporous Al2O3 Modified MCM‐41: A Solar‐Light‐Active Photocatalyst for the Effective Removal of Phenol and Cr (VI) from Water
Authors: Das Kundan Kumar , Patnaik Sulagna , Nanda Binita , Pradhan Amaresh Chandra , Parida Kulamani
Published: February 2019

A series of promising visible light driven ZnFe2O4 modified Al2O3−MCM‐41 nanocomposites were designed by wet impregnation method by loading different wt % (2, 6, 10) of ZnFe2O4 on the surface of mesoporous Al2O3−MCM‐41. All the prepared photocatalysts were analyzed by using X‐ray diffractometers (XRD), Scanning electron microscope (SEM), N2 sorption, Ultra violet‐Visible Diffuse reflectance spectroscopy (UV‐Vis DRS), X‐ray photoelectron spectroscopy (XPS), Fourier‐transmission infrared spectroscopy (FTIR) and High‐resolution transmission electron microscope (HRTEM) techniques to uncover and confirm the formation of phase, morphology and porous structure of the prepared nanocomposites. In the photo‐Fenton reaction, the ZnFe2O4 modified Al2O3−MCM‐41 nanocomposites exhibit a significant catalytic activity for the photo‐Fenton degradation of phenol (40 min, 99%) via photocatalysis and photocatalytic reduction of Cr (VI) (60 min, 66%) under sunlight with an excellent reusability nature. The high photo‐Fenton activity of the composites is mainly attributed to mesoporosity and high surface area of support Al2O3−MCM‐41, proper light harvestation and increased charge transfer efficiency by active species ZnFe2O4 , and suitable band edge potential for hydroxyl radical generation. The photo‐Fenton activities were further supported by the high photocurrent (0.29 mA/cm2) generated by the nanocomposite ZnFe2O4 modified Al2O3−MCM‐41. These results open up a new route for ZnFe2O4 modified Al2O3−MCM‐41as an efficient photo‐Fenton catalyst for environmental remediation with superior activity and higher stability.
Palladium (II) Catalyzed Arylation and Methylene Oxidation of 2, 7‐Dibromo Fluorenes with Heteroaryl Esters: Synthesis of Mesogenic2‐Heteroaryl and 2, 7‐Diheteroaryl‐9‐fluorenones
Authors: Pratap Gallelli , Narasimhaswamy Tanneru , Shanmugam Ponnusamy
Published: February 2019

A facile and unusual palladium catalyzed synthesis of 2‐aryl and 2,7‐diheteroaryl‐9‐fluorenones via a one‐pot CH‐activation‐coupling‐oxidation of 2‐bromo and 2,7‐dibromofluorenes with heteroaryl esters have been achieved. Plausible mechanism for the formation of title compounds invoking palladium mediated direct arylation followed by methylene oxidation is provided. Significantly, among the synthesized compounds, 2,7‐dithiophene‐9‐fluorenones showed enantiotropic smectic mesophases and also optical emission.
Nonrelativistic conformal field theories in the large charge sector
Authors: Kravec S. M. , Pal Sridip
Published: February 2019

Abstract

We study Schrödinger invariant field theories (nonrelativistic conformal field theories) in the large charge (particle number) sector. We do so by constructing the effective field theory (EFT) for a Goldstone boson of the associated U(1) symmetry in a harmonic potential. This EFT can be studied semi-classically in a large charge expansion. We calculate the dimensions of the lowest lying operators, as well as correlation functions of charged operators. We find universal behavior of three point function in large charge sector. We comment on potential applications to fermions at unitarity and critical anyon systems.
On the large R-charge $$ \mathcal{N} $$ = 2 chiral correlators and the Toda equation
Authors: Beccaria Matteo
Published: February 2019

Abstract

We consider

$$ \mathcal{N} $$

N

= 2 SU(N) SQCD in four dimensions and a weak-coupling regime with large R-charge recently discussed in arXiv:1803.00580. If φ denotes the adjoint scalar in the

$$ \mathcal{N} $$

N

= 2 vector multiplet, it has been shown that the 2-point functions in the sector of chiral primaries (Trφ
2)
n
admit a finite limit when g
YM → 0 with large R-charge growing like ∼ 1/g
YM
2
. The correction with respect to

$$ \mathcal{N} $$

N

= 4 correlators is a non-trivial function F(λ; N) of the fixed coupling λ = n g
YM
2
and the gauge algebra rank N. We show how to exploit the Toda equation following from the tt
* equations in order to control the R-charge dependence. This allows to determine F(λ; N) at order

$$ \mathcal{O} $$

O

(λ10) for generic N, greatly extending previous results and placing on a firmer ground a conjecture proposed for the SU(2) case. We show that a similar Toda equation, discussed in the past, may indeed be used for the additional sector (Trφ
2)
n
Trφ
3 due to the special mixing properties of these composite operators on the 4-sphere. We discuss the large R-limit in this second case and compute the associated scaling function F at order

$$ \mathcal{O} $$

O

(λ
7) and generic N. Large N factorization is also illustrated as a check of the computation.
USp(2Nc) SQCD3 with antisymmetric: dualities and symmetry enhancements
Authors: Amariti Antonio , Cassia Luca
Published: February 2019

Abstract

We study various aspects of the 4d/3d reduction of

$$ \mathcal{N} $$

N

= 1 dualities involving USp(2N

c
) gauge theories with 2N

f
fundamentals and one antisymmetric. We discuss the non-trivial role played by the monopole superpotentials in the reduction and obtain new 3d dualities for models with both symplectic and unitary gauge groups. For N

f
= 4 we observe interesting webs of dualities and symmetry enhancements, recovering and extending some results already appeared in the literature.
Electroweak multiplet dark matter at future lepton colliders
Authors: Kadota Kenji , Spray Andrew
Published: February 2019

Abstract

An electroweak multiplet stable due to a new global symmetry is a simple and well-motivated candidate for thermal dark matter. We study how direct searches at a future linear collider, such as the proposed CLIC, can constrain scalar and fermion triplets, quintets and septets, as well as a fermion doublet. The phenomenology is highly sensitive to charged state lifetimes and thus the mass splitting between the members of the multiplet. We include both radiative corrections and the effect of non-renormalisable operators on this splitting. In order to explore the full range of charged state lifetimes, we consider signals including long-lived charged particles, disappearing tracks, and monophotons. By combining the different searches we find discovery and exclusion contours in the mass-lifetime plane. In particular, when the mass splitting is generated purely through radiative corrections, we can exclude the pure-Higgsino doublet below 310 GeV, the pure-wino triplet below 775 GeV, and the minimal dark matter fermion quintet below 1025 GeV. The scenario where the thermal relic abundance of a Higgsino accounts for the whole dark matter of the Universe can be excluded if the mass splitting between the charged and neutral states is less than 230 MeV. Finally, we discuss possible improvements to these limits by using associated hard leptons to idenify the soft visible decay products of the charged members of the dark matter multiplet.
Vacuum block thermalization in semi-classical 2d CFT
Authors: Vos Gideon
Published: February 2019

Abstract

The universal nature of black hole collapse in asymptotically AdS3 gravitational theories suggests that its holographic dual process, thermalization, should similarly be fixed by the universal features of 2d CFT with large central charge c. It is known that non-equilibrium states with scaling dimensions of order c can be sorted into states that eventually thermalize and those that fail to do so. By proving an equivalence between bounded Virasoro coadjoint orbits and certain (in)stability intervals of Hill’s equation it is shown that semi-classical CFTs possess a phase transition where a state that fails to thermalize can be promoted to a thermalizing state by preparing the system beforehand with an energy greater than an appropriate threshold energy. It is generally a difficult problem to ascertain whether a state will thermalize or not. As partial progress to this problem a set of lower bounds are presented for the threshold energy, which can alternatively be interpreted as criteria for thermalization.
Holographic BCFT with Dirichlet boundary condition
Authors: Miao Rong-Xin
Published: February 2019

Abstract

Neumann boundary condition plays an important role in the initial proposal of holographic dual of boundary conformal field theory, which has yield many interesting results and passed several non-trivial tests. In this paper, we show that Dirichlet boundary condition works as well as Neumann boundary condition. For instance, it includes AdS solution and obeys the g-theorem. Furthermore, it can produce the correct expression of one point function, the boundary Weyl anomaly and the universal relations between them. We also study the relative boundary condition for gauge fields, which is the counterpart of Dirichlet boundary condition for gravitational fields. Interestingly, the four-dimensional Reissner-Nordström black hole with magnetic charge is an exact solution to relative boundary condition under some conditions. This holographic model predicts that a constant magnetic field in the bulk can induce a constant current on the boundary in three dimensions. We suggest to measure this interesting boundary current in materials such as the graphene.
Flavor symmetries and the topology of special Kähler structures at rank 1
Authors: Argyres Philip C. , Lotito Matteo
Published: February 2019

Abstract

We propose a method for determining the flavor charge lattice of the continuous flavor symmetry of rank-1 4d

$$ \mathcal{N} $$

N

= 2 superconformal field theories (SCFTs) and IR free gauge theories from topological invariants of the special Kähler structure of the mass-deformed Coulomb branches (CBs) of the theories. The method is based on the middle homology of the total space of the elliptic fibration over the CB, and is a generalization of the F-theory string web description of flavor charge lattices. The resulting lattices, which we call “string web lattices”, contain not only information about the flavor symmetry of the SCFT but also additional information encoded in the lattice metric derived from the middle homology intersection form. This additional information clearly reflects the low energy electric and magnetic charges of BPS states on the CB, but there are other properties of the string web lattice metric which we have not been able to understand in terms of properties of the BPS spectrum. We compute the string web lattices of all rank-1 SCFTs and IR free gauge theories. We find agreement with results obtained by other methods, and find in a few cases that the string web lattice gives additional information on the flavor symmetry.
Consistency Theory for the General Nonparametric Classification Method
Authors: Chiu Chia-Yi , Köhn Hans-Friedrich
Published: February 2019

Parametric likelihood estimation is the prevailing method for fitting cognitive diagnosis models—also called diagnostic classification models (DCMs). Nonparametric concepts and methods that do not rely on a parametric statistical model have been proposed for cognitive diagnosis. These methods are particularly useful when sample sizes are small. The general nonparametric classification (GNPC) method for assigning examinees to proficiency classes can accommodate assessment data conforming to any diagnostic classification model that describes the probability of a correct item response as an increasing function of the number of required attributes mastered by an examinee (known as the “monotonicity assumption”). Hence, the GNPC method can be used with any model that can be represented as a general DCM. However, the statistical properties of the estimator of examinees’ proficiency class are currently unknown. In this article, the consistency theory of the GNPC proficiency-class estimator is developed and its statistical consistency is proven.
Active management of atrial fibrillation or flutter in emergency department patients with renal impairment is associated with a higher risk of adverse events and treatment failure
Authors: Scheuermeyer Frank X. , Wong Hubert , Barrett Tyler W. , Christenson Jim , Grafstein Eric , Grunau Brian , Wiens Matt , Innes Grant
Published: February 2019

Objective

Atrial fibrillation or flutter (AFF) patients with renal impairment have poor long-term prognosis, but their emergency department (ED) management has not been described. We investigated the association of renal impairment upon outcomes after rate or rhythm control (RRC) including ED-based adverse events (AE) and treatment failure.

Methods

This cohort study used an electrocardiogram database from two urban centres to identify consecutive AFF patients and reviewed charts to obtain comorbidities, ED management, including RRC, prespecified AE, and treatment failure. Patients were dichotomized into a normal estimated glomerular filtration rate (eGFR) > 60 mL/min/1.73 m2) or impaired renal function (“low eGFR”). Primary and secondary outcomes were prespecified AEs and treatment failure, respectively. We calculated 1) adjusted excess AE risk for patients with decreased renal function receiving RRC; and 2) adjusted odds ratio of RRC treatment failure.

Results

Of 1,112 consecutive ED AFF patients, 412 (37.0%) had a low eGFR. Crude AE rates for RRC were 27/238 (11.3%) for patients with normal renal function and 26/103 (25.2%) for patients with low eGFR. For patients with low eGFR receiving RRC, adjusted excess AE risk was 13.7%. (95% CI 1.7 to 25.1%). For patients with low eGFR, adjusted odds ratio for RRC failure was 3.07. (95% CI 1.74 to 5.43)

Conclusions

In this cohort of ED AFF patients receiving RRC, those with low eGFR had significantly increased adjusted excess risk of AE compared with patients with normal renal function. Odds of treatment failure were also significantly increased.
COMPATIBLE SYSTEMS OF GALOIS REPRESENTATIONS ASSOCIATED TO THE EXCEPTIONAL GROUP
Authors: BOXER GEORGE , CALEGARI FRANK , EMERTON MATTHEW , LEVIN BRANDON , MADAPUSI PERA KEERTHI , PATRIKIS STEFAN
Published: February 2019

We construct, over any CM field, compatible systems of $l$-adic Galois representations that appear in the cohomology of algebraic varieties and have (for all $l$) algebraic monodromy groups equal to the exceptional group of type $E_{6}$.
Positive psychological traits, school functioning, and psychological adjustment in elementary schoolchildren
Authors: Arslan Gökmen
Published: February 2019

The present study explored the associations among positive psychological traits, school functioning, and psychological adjustment of elementary schoolchildren. Participants included 392 children in Grades 6–8 attending a Turkish public elementary school. There were 48.2% (189) female and 51.8% (203) male participants, and they ranged in age from 11 to 14 years ( M = 12.83, SD = .94). Findings of the study indicated that youths with high positive psychological traits reported higher levels of prosocial behaviour, school belonging and academic achievement, and lower levels of externalising and internalising problems. Path analysis outcomes revealed that the positive psychology constructs had significant and large associations with prosocial behaviour, school belonging, internalising and externalising problems, as well as small-to-large associations with student academic achievement. Overall, the combination of these positive traits, namely covitality, had stronger associations with youths’ school functioning and psychological adjustment than the constructs that comprise covitality. The outcomes suggest substantial associations between positive psychological traits and youths’ school-based and psychological characteristics.
Property, territory, and colonialism: an international legal history of enclosure
Authors: Jones Henry
Published: February 2019

This paper is concerned with how law organises and controls space. It offers a new history of enclosure in the context of early English colonialism. By drawing this connection, the paper opens up new lines of enquiry into how law organises and produces space at both the domestic and international scale.
Associations of dietary energy density with body composition and cardiometabolic risk in children with overweight and obesity: role of energy density calculations, under-reporting energy intake and physical activity
Authors: Gomez-Bruton Alejandro , Arenaza Lide , Medrano Maria , Mora-Gonzalez Jose , Cadenas-Sanchez Cristina , Migueles Jairo H. , Muñoz-Hernández Victoria , Merchan-Ramirez Elisa , Martinez-Avila Wendy Daniela , Maldonado Jose , Oses Maddi , Tobalina Ignacio , Gracia-Marco Luis , Vicente-Rodriguez German , Ortega Francisco B. , Labayen Idoia
Published: February 2019

This study examined (1) the association of dietary energy density from solid (EDS) and solid plus liquids (EDSL) with adiposity and cardiometabolic risk factors (CRF) in children with overweight and obesity, (2) the effect of under-reporting on the mentioned associations and (3) whether the association between ED and body composition and CRF is influenced by levels of physical activity. In a cross-sectional design, 208 overweight and obese children (8–12-year-old; 111 boys) completed two non-consecutive 24 h recalls. ED was calculated using two different approaches: EDS and EDSL. Under-reporters were determined with the Goldberg method. Body composition, anthropometry and fasting blood sample measurements were performed. Moderate to vigorous physical activity (MVPA) was registered with accelerometers (7-d-register). Linear regressions were performed to evaluate the association of ED with the previously mentioned variables. Neither EDS nor EDSL were associated with body composition or CRF. However, when under-reporters were excluded, EDS was positively associated with BMI (P=0·019), body fat percentage (P=0·005), abdominal fat (P=0·008) and fat mass index (P=0·018), while EDSL was positively associated with body fat percentage (P=0·008) and fat mass index (P=0·026). When stratifying the group according to physical activity recommendations, the aforementioned associations were only maintained for non-compliers. Cluster analysis showed that the low-ED and high-MVPA group presented the healthiest profile for all adiposity and CRF. These findings could partly explain inconsistencies in literature, as we found that different ED calculations entail distinct results. Physical activity levels and excluding under-reporters greatly influence the associations between ED and adiposity in children with overweight and obesity.
Modelling of growth alteration in Japanese quail after a selection experiment for body weight at 4 weeks of age
Authors: Abou Khadiga G. , Mahmoud B. Y. F. , El-Full E. A.
Published: February 2019

The current study investigated the influence of selection for body weight (BW) on growth curve parameters in two lines of Japanese quail through a mixed model approach. Live BWs of 1400 Japanese quail were recorded at 3-day intervals from hatching to 42 days of age. Birds were distributed equally across lines (selected and control) and sexes (male and female). The asymptotic weight parameter (β0) values were always higher in Gompertz than Richards models in both lines. The values ofβ0were higher in the selected than control lines and in females than males across models. Differences were found in the inflection point for age and weight across lines and sexes. Values of the growth rate parameter (β2) ranged from 0.06 to 0.10 in both models, favouring males over females in both lines. Lower weights at the inflection point of both models were observed in the control line. Determination coefficient (R2) of both models in different genetic groups and sexes was similar. Mean square error (MSE) values of the Gompertz model were lower for females in selectedv.control lines. In contrast, MSE values of the Richards model were lower for selected malesv.control males. According to the criteria of choice (highestR2and lowest MSE, Akaike information criterion and Bayesian information criterion), the Richards model was considered the best fitting model for the growth data of males, while the Gompertz model was the best for growth data of female quails in both lines.
Parasite diversity associated with African penguins (Spheniscus demersus) and the effect of host and environmental factors
Authors: Espinaze Marcela P. A. , Hui Cang , Waller Lauren , Dreyer Francois , Matthee Sonja
Published: February 2019

The African penguin (Spheniscus demersus) is a critically endangered species endemic to southern Africa. Limited information is available on the parasite diversity associated with the species in natural settings. This study explores the diversity and incidence of parasites associated with African penguins and their nests, and records the effect of host and environmental factors on parasite infestation. Ecto-, haemo- and helminth parasites were recorded from 210 adult birds, 583 chicks and 628 nests across five colonies (two mainland and three islands) along the south-western coast of South Africa, in 2016 and 2017. Mean nest density (total and active nests) and climate variables (temperature and precipitation) were obtained for each colony.Parapsyllus humboldtiwas the most abundant and prevalent ectoparasite on penguins and in nests (69.10 and 57.80%, respectively), while Piroplasmorida/Haemospororida (33.51%) andCardiocephaloidesspp. (56.17%) were the most prevalent haemo- and helminth parasites of penguins, respectively. In general parasite abundance and prevalence was significantly affected by penguin age (chicksvsadults), location (mainlandvsislands), nest density (total and active nests) and season (springvsautumn/winter). It is concluded that parasite infestations are structured and that penguin chicks at mainland colonies are more susceptible to parasite infestations during spring.
Infrared Wide-Field Surveys
Authors: Epchtein N.
Published: February 2019

Optical wide-field sky surveys have long been basic tools of astronomical
investigations. Their extension to the near infrared spectral range, unattainable
with photographic techniques, is now possible thanks to the considerable
improvements in infrared array technology that have been achieved in the past few
years. The astronomical motivations for all-sky 2 μm surveys are summarized, and a
brief technical description of the on-going projects, in particular DENIS (Deep
Near Infrared Southern Sky Survey) that will be carried out at the European
Southern Observatory in 1994–97, is presented.
Beijing — Arizona Color (BAC) Sky Survey
Authors: Chen J.-S.
Published: February 2019

Observational astronomy can be roughly split into two categories of study:
surveys, designed to detect and categorize objects, and detailed observations that
provide physical insight into individual objects. The application of large format
CCDs makes it possible to conduct surveys which yield quantitative information for
large samples of objects.
The Second Palomar Sky Survey
Authors: Reid I.N.
Published: February 2019

The 48-inch Oschin Schmidt telescope at Palomar Observatory was used to
obtain the first deep, optical, wide-field survey, covering almost two-thirds of
the sky between November 1949 and December 1958 (with plates for the Whiteoak
extension, to δ
c
= −42°, taken in 1964/5). The original survey was taken in two
passbands — wide blue and narrow red — on 103a emulsion, and covers one hemisphere
in 643 fields with a spacing of 6 degrees between centres. In 1987, plate-taking
started for the second Palomar Sky Survey, POSS II, which is intended to cover the
northern hemisphere in three passbands, blue (IIIa-J + GG385 filter), red (IIIa-F
+ RG610) and near-infrared (IVN + RG9). Given the extremely restricted overlap
between fields in the old survey, we have followed the example of the UK Schmidt
ESO/SERC surveys and have adopted a 5-degree spacing between fields. To date
(31.7.93), we have acquired plates of acceptable quality for 597 fields (67%) of
the IIIa-J survey, 668 fields (75%) of the IIIa-F and 253 fields (28%) of the
IVN.
The Palomar Observatory-European Observatory Photographic Atlas of the
Northern Sky
Authors: Class S. , Quebatte J. , Strigl G.
Published: February 2019

In 1990, following an agreement with Caltech (Pasadena), the production of
the copies of the POSS II was started at ESO. In total, 894 fields, each in three
colours (B, R, I), will be copied on-film and on-glass.
First Steps Toward a CCD-Based Sky Patrol
Authors: Kroll P. , Lehmann T.
Published: February 2019

A sky patrol aims to record, as often as possible, the whole sky visible from
an observing site down to a certain magnitude in one or more optical or
near-optical wavelength regions.
SNe from Surveys and Patrols
Authors: Pollas C.
Published: February 2019

The name of Zwicky is attached to the first photographic Palomar Survey and
to the History of SNe study. An exciting study resumed by the striking image (M =
−19) of a transient source appearing at extragalactic distance, as bright as the
total magnitude of its parent galaxy. Expected to explode once a century, such an
event is rare. But the more galaxies are checked the more SNe are found. That is
why the wide-field is a good tool. The Palomar team SNe activity was followed by a
quiet period of the whole SNe discovery (Fig. 1); from those the Cero El Robles
search emerged in the early eighties. Several important patrols continued with
Schmidt telescopes of size about 0.5 m (Bern, Hungary, Urss…) in spite of the low
level of SNe found. Important because knowing that no SN exploded in a galaxy
(especially in the sample of nearby galaxies) is the basis of the statistics. The
SNe production increased in the late eighties. At the same time, the closest
modern SN (1987A) led for the first time to the use of a number of instruments
complementing each other to increase our understanding of SNe. But more important
than the production of new SNe, is the increase of their spectroscopic
classification which is necessary to the SNe work.
Simultaneous Optical/Gamma-Ray Observations of Gamma-Ray Bursts
Authors: Greiner J.
Published: February 2019

To search for optical counterparts of γ-ray bursters, a collaborative project
has been initiated together with the γ-ray burst instrument team (BATSE) on the
Compton Gamma-Ray Observatory (GRO) which provides times and locations of γ-ray
bursts. On the optical part of this project, representatives of 10 observatories
are presently involved.
Wide-Field Photographic Versus Wide-Field CCD Techniques in the Activity
Analysis of dM Stars
Authors: Szécsényi-Nagy G.
Published: February 2019

The Galaxy is abundant in red dwarf stars. According to statistical analyses,
their majority is unstable. Simultaneously, more than 60% of the variable stars
known in the solar vicinity (r < 20 pc) are flare stars and taking into
account the number of BY Dra stars too the proportion of red dwarfs amongst local
variables is superior to three quarters. Their absolute visual magnitudes range
from +6 to +17.5 or even more (Szécsényi-Nagy 1986a). During flare events their
brightness may reach a maximum corresponding to an enhancement of 1000–10,000
times. The amplitude of a large flare in the U band may be as high as 8–10
magnitudes. The events take place nonperiodically in unpredictable moments; no
unquestionable periodicity has been found in the time distribution of stellar
flares. However the activity level of various flare stars is considerably
different. Some of them show observable flare ups with a mean frequency of 1 per
hour whilst others produce only one event per annum. For the scarcity of the
phenomenon, traditional photoelectric photometry of individual stars is not an
adequate means to a better understanding of flare stars.
The Hitchhiker Parallel Camera and Studies of Faint Galaxies
Authors: Jones J.B. , Driver S.P. , Davies J.I. , Phillipps S. , Morgan I. , Disney M.J.
Published: February 2019

The Hitchhiker camera performs CCD imaging of an off-axis field on a 4 m
telescope in parallel with the normal on-axis scientific programmes. Using a
dichroic beam splitter it images in two colours simultaneously, obtaining deep
images in random fields suitable for survey work. Recent research projects have
given particular emphasis to studies of faint galaxies and we present new results
on the association of faint blue galaxies with candidate giant galaxies.
Optical Systems for the ‘Large Imaging Telescope’ (Lite)
Authors: Jena Carl Zeiss
Published: February 2019

With the first demands to the LITE-project being available in summer 1992, it
was obvious that the known systems such as Slevogt, Schmidt or
Ritchey-Chrétien-Cassegrain did not offer an attempt at a solution.
Wide-Field-Imaging 3-Mirror-Systems by High Light Gathering Power and a
Wide-Field Optical System for the ‘Large Imaging Telescope’ (Lite)
Authors: Laux U.
Published: February 2019

The desire of astronomers for wide field telescope systems which surpass the
RCC (1:8 max. 1.5 degree) in light gathering power and field of view are relative
concrete today. For this type of telescope, detectors planned ARE CCDs in
multichip arrangement.
Use of Kodak Tech-Pan Film at the Ukstu
Authors: Parker Q.A. , Phillipps S. , Morgan D.H. , Malin D.F. , Russell K.S. , Hartley M. , Savage A.
Published: February 2019

Kodak Technical Pan (Tech Pan) emulsion is an extremely fine grained, high
resolution, panchromatic negative film with extended red sensitivity. It has been
produced under this name since about 1980 (Kodak P–255, 1981) and is available on
Kodak's Estar base in a number of thicknesses and sizes. The thick ∗∗base Tech Pan
is designated 4415 and has been used with great success by the amateur
astronomical community for many years (e.g. Martys 1991). Its astronomical
potential was recognised early by Everhart (1981). However, tests at professional
telescopes (e.g. West et al. 1981) and early sensitometer tests at the UK Schmidt
Telescope (UKST) in 1981 and 1987 were discontinued when the glass and film
samples did not respond well to normal hypersensitisation techniques. These and
other difficulties led to a lack of interest among the professional astronomical
community until quite recently (Russell et al. 1992; Parker & Malin 1992).
The first successful use of 14 × 14 inch hypered Tech-Pan 4415 film in the UKST
was in March 1991. Films were obtained which exhibited excellent image quality and
resolution. Furthermore, in good seeing these appeared to be about 1 magnitude
deeper than the equivalent IIIa-F emulsion on glass but with considerably lower
grain noise. This result was achieved because two main problems associated with
Tech-Pan and film use in the UKST have been resolved. These were:

1)

obtaining Tech-Pan film with long exposure speed sufficient for deep
astronomical photography (i.e. reduction of low intenstiy reciprocity
failure);

2)

overcoming the practical difficulties of mounting large-format
flexible film at the UKST's curved focal surface.
Digitization in Astronomy
Authors: Monet D.G.
Published: February 2019

Ground-based wide-field optical astrometry is in a state of technological
turmoil. The photographic plate appears to be an endangered species, and the best
alternative, the charge coupled device (CCD), is not ready to replace it This
discussion presents various issues related to this inevitable transition from
plates to CCDs, and suggests areas where research is needed before the appropriate
CCD detectors can be designed.
Astrometric Programs by the New Hamburg Plate Measuring Machine
Authors: de Vegt Chr. , Winter L. , Zacharias N.
Published: February 2019

With the new Hamburg astrometric measuring machine, large sets of plates can
be digitized very quickly with submicrometer accuracy. In particular about 2000
plates of the AGK2-catalog, mean epoch 1930, can be remeasured now for the first
time to their limiting magnitude, about B = 11. The new AGK2-data therefore will
cover practically the whole AC-catalog and TYCHO-stars in the northern
hemisphere.

All plates will be reduced using the HIPPARCOS results as the reference frame
when available in 1996. The new AGK2-data will provide a unique data base for the
determination of high accuracy proper motions (about 2 mas/yr) of all TYCHO stars
in the northern hemisphere. Furthermore, for the first time a dense reference
frame for a final reduction of the Astrographic Catalog (AC) and the large deep
sky surveys will be generated by this catalog. The inferior situation in the
southern hemisphere will be addressed briefly.
A Deep Wide-Field Survey from Digitally Stacked Schmidt Plates
Authors: Hawkins M.R.S.
Published: February 2019

Over the last 18 years or so a large-scale monitoring programme has been
undertaken with the UK 1.2 m Schmidt telescope in field 287 at 21h 28m, −45 deg.
Plates have been taken over all timescales from 1 hour to 17 years in red and blue
passbands, and large numbers of plates have also been taken in other passbands to
give deep coverage in U, B, V, R and I. The field is calibrated with some 200 CCD
and photoelectric standards, and covers approximately 25 square degrees.
A Universal Microphotometer by a Rotating Slit: Brief Description and Use in
Astronomical Tasks
Authors: Kotrč P. , Zicha J.
Published: February 2019

Several types of fast digitization devices consisting of CCD cameras and
frame grabbers have appeared and been implemented in astronomical practice during
the last decade. Nevertheless, various types of classical scanning devices are
still used for precise digitization of astronomical images and spectrograms. Among
them, a new type of microphotometer with a rotating slit (UMF) was adjusted and
installed at the Ondřejov Observatory (Zicha et al. 1992). Technical parameters of
the device are as follows:
Image Detection, Characterization and Classification, and the Future Role of
CCDS in Wide-Field Astrometry
Authors: van Altena W.F.
Published: February 2019

The extraction and characterisation of information from photographic
emulsions is the subject of this review. Since the major Schmidt Telescope full
sky surveys form the bulk of the photographic emulsions currently under intensive
study, I will limit my remarks to them, although most would be applicable to any
of the emulsions now in use. A listing of the major direct imaging surveys is
given in the article by van Altena et al (1993).
Automatic Morphological Classification of Galaxies
Authors: Okamura S. , Doi M. , Fukugita M. , Kashikawa N. , Sekiguchi M. , Shimasaku K. , Yasuda N.
Published: February 2019

We study the performance and limitations of the morphological classification
method based on luminosity concentration and mean surface brightness. In
particular, the effects of the different colour bands and of a finite seeing are
investigated.
The System and Quality of the AGK3U
Authors: Taff L.G.
Published: February 2019

The methods used to assess the quality and the system of the AGK3U
(Bucciarelli et al. 1992) are reviewed. However, the point of this paper is that
all star catalogs should undergo a comparable evaluation. It is too easy to follow
the recipes of statistics, examine internal measures, declare success, and move
on. All recipes can be ruined with the wrong ingredients and the theorems of
statistics are no different. Since it is impossible to verify that the hypotheses
are a priori fulfilled, one has to be resourceful and devise methods which fully
test the outcome a posteriori. The AGK3U has been so examined; our efforts are
described herein. (The AGK3U is the first attempt to combine astrometrically
reduced Schmidt plate positions with those from astrographic plates [Taff 1989;
Taff et al. 1990]. Our sub-plate code will be available soon because of NASA
support to make it portable.)
GSC 1.2 — A Subplate Reduction of the GSC
Authors: Bucciarelli B. , Doggett J.B. , Sturch C.R. , Lasker B.M. , McLean B.J. , Lattanzi M.G. , Taff L.G.
Published: February 2019

The original version of the HST Guide Star Catalog (GSC 1.0, Lasker et al.
1990, and following papers) contains systematic errors which typically begin
from the plate
center and increase with radius (Taff et al. 1990a). In a residual plot against
CAMC stars this shows as high correlations between neighboring residuals. This is
due to the inability of a global polynomial to map the metric of a Schmidt plate.
A new reduction of the GSC measures (GSC 1.2) based on the subplate method (Taff
1989) is partially complete. We report on it for the northern data from the
Palomar Quick V plates, with 20 minute exposures, nearly all taken in the
1982–1984 interval.
Some Results of CCD-Camera Based Astrometric Plate Measurements
Authors: Zacharias N. , de Vegt C. , Winter L. , Weneit W.
Published: February 2019

A measuring accuracy of about 0.3 μm per coordinate for well exposed stellar
images is achieved over the entire usable measuring area of more than 200 × 200
mm2 with the CCD-camera upgrade of the ‘old’ Mann
comparator.

The external plate-to-plate comparison shows that the error due to emulsion
shifts dominates, which results in an overall accuracy of about 0.8 μm.
Astrometric Standard Fields for CCD Observations of Double Stars
Authors: Sinachopoulos D. , Oblak E. , Geffert M. , Colin J. , LeCampion J.-F. , Hopp U.
Published: February 2019

The number of known double stars is steadily increasing, thanks to
ground-based and space observations. Therefore the ratio of known double to single
stars has to be revised upwards continuously. With the Hipparcos parallaxes it
will be possible to get stellar statistics for precisely defined volumes of space.
This will lead to strong constraints on all astrophysical calibrations of masses,
spectral types and luminosities in the solar neighbourhood. A European network of
laboratories was created in August 1990 in order to remedy the lack of photometric
data for close visual double stars. This network intends to study all aspects of
formation and evolution of double and multiple star systems. The immediate goal of
the group is to provide the scientific community with a compilation of known
photometric data on a large selection of close visual double stars and to
significantly enlarge this information by new observations with modern devices. A
photometric database of stellar systems is being compiled from most widely used
photometric systems in collaboration with the ‘Centre de Données Stellaires’ of
Strasbourg.
Peculiarities of the Internal Photometrical Calibration Method Using Density
Stellar Profiles
Authors: Markov H.
Published: February 2019

On photographic plates taken for the purposes of classical stellar photometry
(using a standard stellar sequence) there usually is no external photometrical
calibration scale, neither a wedge nor spots; and hence the transition to relative
intensity is a problem. The construction of a characteristic curve D(I) (hereafter
CHC) by combining density profiles of several standard stars is a perfect solution
of this task (Agnelli et al. 1979; de Vaucouleurs 1984). We have developed this
method in order to obtain internal photometric calibrations for a large number of
plates taken at the RC focus of the 2m telescope (F/8, scale 12.86) at the
National Astronomical Observatory (NAO); these do not have any photometrical
calibration. Our long term project provides UBV stellar photometry in the central
regions of some globular clusters — M5, M10, M12, M56, M71, for which we have good
collections of short exposure plates. The task also requires a background
determination which can be done precisely only in relative intensities. We apply
the method using Arp's UBV standard sequence in M5 globular cluster. In our
investigation we demonstrate some peculiarities of the method:
Multi-Parametric Iris-Photometry
Authors: Georgiev T.B.
Published: February 2019

Usually, the reduction of iris-measurements d of
stellar photographic images to magnitudes m is
performed with one-dimensional regression m =
f(d), obtained using standard stars (Burkhead
& Seeds 1971). The derivation of accurate magnitudes is difficult due to
many factors (Butler 1972). Considering that the star image shape contains
information on the sensitivity of the plate and the color of the star, Vladimirov
(1978) recommended multi-parametric determination of the magnitudes, using a
system of isodense bounded areas of the stellar images. Here this approach is
implemented using software that performs a general multi-parametric method (MPM)
of iris-photometry.
A Photometrical Investigation on the RC System of the 2m Ritchey-Chretien
Coude Telescope of the Rozhen Observatory
Authors: Getov R.G.
Published: February 2019

Surface photometry techniques of data processing are applied for the
qualitative analysis on the reflectivity of the two mirror system in the prime
focus of the 2m Ritchey-Chrétien Coudé telescope of the Rozhen Observatory. There
are considerable variations in the reflectivity, up to ±30%. An estimation on the
upper limit of the average reflectivity, about 68% ±1%, of the two-mirror RC
system is made. A loss of about 0.5 magnitudes in the limiting magnitude due to
the low reflectivity and to the decrease in the reflecting surface is
found.
Brightness Calibration of Digitized Objective-Prism Plates
Authors: Engels D. , Cordis L. , Köhler T.
Published: February 2019

Currently, IIIa-J objective-prism plates from the Calar Alto and ESO Schmidt
telescopes are used at the Hamburg Observatory to search for and to identify new
astronomical objects. Major projects are the Hamburg Quasar Survey, the
Hamburg-ESO Survey, and the Hamburg-Munich collaboration to identify sources from
the ROSAT All-Sky Survey (cf. contributions to this conference by Hagen et al.,
Wisotzki, and Voges). The objective-prism plates are digitized with a PDS
microphotometer. To determine the brightness of the digitized objects, a method to
calibrate the plates was developed, using an internally determined characteristic
curve and its external calibration with photometric sequences. Having spectral
information, we are able to synthesize the Johnson B-filter as this filter is
fully covered by the spectra.
Digital Processing on Comets
Authors: Kubáček D. , Pittich E.M. , Zvolánková J.
Published: February 2019

Several digital techniques have been used to remove large-scale background
variations caused by manufacturing and technology of the photographic processing
on old photographic plates ORWO ZU-21. Suppression of these large-scale background
variations improved the study of large-scale phenomena in cometary plasma tails
and the determination of the solar wind characteristics.

The results obtained from five images of the comet Bradfield 1987 XXIX have
been compared. It has been shown that the simple digital techniques used were
applicable also to photographic plates with images of lesser quality. They may be
utilized in the treatment of old photographic plate archives.
Data Storage Technology: Coping by the Evolution
Authors: Pirenne B.
Published: February 2019

Modern astronomical data is now either produced directly in digital form or
converted from a high resolution analog medium to digital form. These data are
therefore best conserved and handled with computer techniques.

This paper will first define ‘computer storage technology’ as the set of
software and hardware tools needed to perform the management of an archive and the
control of the archiving and redistribution operations. Various implementation
choices that one faces when setting up an archive will be reviewed. The chasm
between the life expectancy of the stored data and that of the equipment and
procedures needed to handle it will be one of the most important points
considered.

Currently available technological solutions will be reviewed. Future trends
of the storage technology will be discussed in comparison with the expected data
production rate of the next generation astronomical instruments.
Aladin: An Interactive Deep Sky Mapping Facility
Authors: Paillou Ph. , Bonnarel F. , Ochsenbein F. , Crézé M.
Published: February 2019

Any astronomer, whether preparing observation runs or reducing data, requires
access to information concerning the objects under investigation. Ideally the data
should be from several wavelengths and should be as quantitative as possible. This
leads to the concept of developing simultaneous interactive access to sky surveys,
initially at optical wavelengths, and with state-of-the-art information systems
for all field objects.

In order to satisfy this requirement, the CDS (Centre de Données
astronomiques de Strasbourg) is developing a ‘Deep Sky Mapping Facility’ project,
Aladin, which aims to connect the data stored at CDS (astronomical catalogues and
Simbad), to pixel data from continuously updated deep optical sky
surveys.
Client/Server Access to the Simbad Database Within the Aladin Project
Authors: Bonnarel F. , Divetain E. , Ochsenbein F. , Paillou Ph. , Wenger M.
Published: February 2019

Aladin, the Deep Sky interactive Facility, is a new CDS project which
provides interactive access to both sky surveys, (starting with optical ones) and
also to catalogue data about the studied field objects (Paillou et al.
1993).
Direct-Photography Observations by the 2 M RCC Telescope at Nao-Rozhen:
Catalogue of Plates and Archive-Data Analysis
Authors: Stavrev K.Y. , Barzova I.S.
Published: February 2019

The 2m Ritchey-Chrétien-Coudé (RCC) telescope of the National Astronomical
Observatory, situated in the Rozhen massif of the Rhodope Mountains, started
operating in 1980 (for a detailed description of the telescope see Gutcke [1979]).
Since then, 2000 direct photographs have been obtained, most of them covering a 1°
× 1° area on the sky with resolution 12.9 sec/mm.
Flare Stars Database
Authors: Tsvetkov M. , Chukova M. , Tsvetkova K.
Published: February 2019

The important role of flare stars (UV Ceti type variables) in astrophysics is
due to the fact that the flare activity is not only typical for red stars with
small masses but is a necessary stage during their evolution. The flare star
search in stellar aggregates has led to the accumulation of rich observational
material allowing us to look for statistical regularities in star formation and
evolution. At present, there are more than 1500 known flare stars in the Galaxy;
these were discovered mainly during the last 30 years. Most results of the long
term monitoring with wide-field telescopes are listed in existing catalogues of
flare stars in stellar aggregates and in the solar neighbourhood. These catalogues
and their machine-readable versions were the basis for the present database of
flare stars in the Galaxy.
Vertical Metallicity Gradient of the Galaxy Based on UBV Starcount
Data
Authors: Yamagata T. , Yoshii Y.
Published: February 2019

The spatial distribution of metal abundance in the Galaxy has been analyzed
using the UBV starcount data recently obtained in two high-latitude regions of the
North Galactic Pole (NGP) and Selected Area 54 (SA54).

A least-squares analysis was performed to determine the vertical metallicity
gradient for each of the thin and thick disk components that gives a reasonable
fit to the observed U-B and B-V colour distributions to V = 18 mag. The most
probable value of the vertical gradient is obtained as
d[Fe/H]/dz
= −0.5 kpc−1 for the thin disk, and −0.1
kpc−1 for the thick disk.
The Vertical Structure and Kinematics of the Galaxy
Authors: Soubiran C.
Published: February 2019

A sample including 2370 stars with (U, V) velocities has been analyzed up to
z = 2.5 kpc. It is shown that the observed vertical
gradient in the velocity distribution can be explained by the sum of 3 discrete
populations with constant kinematics. The observations are well fitted by
exponential density laws for the thin disk and the thick disk with scale lengths
of 280 pc and 700 pc respectively, and with local densities of 6% and 0.15% for
the thick disk and halo respectively.