bluuebunny/crossref_metadata_2025 huggingface dataset:
Surveillance for malaria outbreak on malaria-eliminating islands in Tafea Province, Vanuatu after Tropical Cyclone Pam in 2015
Authors: CHAN C. W. , IATA H. , YAVIONG J. , KALKOA M. , YAMAR S. , TALEO G. , ISOZUMI R. , FUKUI M. , AOYAMA F. , POMER A. , DANCAUSE K. N. , KANEKO A.
Published: September 2016

The risk of malaria outbreak surfaced in Vanuatu after Tropical Cyclone (TC) Pam in March 2015. In June and July 2015 we conducted malariometric surveys on the islands of Tanna, Aneityum, and Erromango in Tafea Province, where malaria elimination had been targeted, to determine if malaria incidence had increased after TC Pam. No Plasmodium infection was detected by microscopy and PCR in 3009 survey participants. Only 6·3% (190/3007) of participants had fever. Spleen rates in children aged ⩽12 years from Aneityum and Tanna were low, at 3·6% (14/387) and 5·3% (27/510), respectively. Overall bed net use was high at 72·8% (2175/2986); however, a significantly higher (P < 0·001) proportion of participants from Aneityum (85·9%, 796/927) reported net use than those from Tanna (67·1%, 751/1119) and Erromango (66·8%, 628/940). A recent decrease in malaria incidence in Tafea Province through comprehensive intervention measures had reduced the indigenous parasite reservoir and limited the latter's potential to spur an outbreak after TC Pam. The path towards malaria elimination in Tafea Province was not adversely affected by TC Pam.
Stable finite element approximation of a Cahn–Hilliard–Stokes system coupled to an electric field
Authors: NÜRNBERG ROBERT , TUCKER EDWARD J. W.
Published: September 2016

We consider a fully practical finite element approximation of the Cahn–Hilliard–Stokes system:
$$\begin{align*}
\gamma \tfrac{\partial u}{\partial t} + \beta v \cdot \nabla u -
\nabla \cdot \left(
\nabla w \right) & = 0 \,, \quad
w= -\gamma \Delta u + \gamma ^{-1} \Psi ' (u) - \tfrac12 \alpha c'(\cdot,u)
| \nabla \phi |^2\,, \\
\nabla \cdot (c(\cdot,u) \nabla \phi) & = 0\,,\quad
\begin{cases}
-\Delta v + \nabla p = \varsigma w \nabla u, \\
\nabla \cdot v = 0, \end{cases}
\end{align*}$$
subject to an initial condition u0(.) ∈ [−1, 1] on the conserved order parameter u ∈ [−1, 1], and mixed boundary conditions. Here, γ ∈ $\mathbb{R}_{>0}$ is the interfacial parameter, α ∈ $\mathbb{R}_{\geq0}$ is the field strength parameter, Ψ is the obstacle potential, c(⋅, u) is the diffusion coefficient, and c′(⋅, u) denotes differentiation with respect to the second argument. Furthermore, w is the chemical potential, φ is the electro-static potential, and (v, p) are the velocity and pressure. The system has been proposed to model the manipulation of morphologies in organic solar cells with the help of an applied electric field and kinetics.
Polygraphs of finite derivation type
Authors: GUIRAUD YVES , MALBOS PHILIPPE
Published: September 2016

Craig Squier proved that, if a monoid can be presented by a finite convergent string rewriting system, then it satisfies the homological finiteness condition left-FP3. Using this result, he constructed finitely presentable monoids with a decidable word problem, but that cannot be presented by finite convergent rewriting systems. Later, he introduced the condition of finite derivation type, which is a homotopical finiteness property on the presentation complex associated to a monoid presentation. He showed that this condition is an invariant of finite presentations and he gave a constructive way to prove this finiteness property based on the computation of the critical branchings: Being of finite derivation type is a necessary condition for a finitely presented monoid to admit a finite convergent presentation. This survey presents Squier's results in the contemporary language of polygraphs and higher dimensional categories, with new proofs and relations between them.
MULTIVARIATE TREND–CYCLE EXTRACTION WITH THE HODRICK–PRESCOTT FILTER
Authors: Poloni Federico , Sbrana Giacomo
Published: September 2016

The Hodrick–Prescott filter represents one of the most popular methods for trend–cycle extraction in macroeconomic time series. In this paper we provide a multivariate generalization of the Hodrick–Prescott filter, based on the seemingly unrelated time series approach. We first derive closed-form expressions linking the signal–noise matrix ratio to the parameters of the VARMA representation of the model. We then show that the parameters can be estimated using a recently introduced method, called “Moment Estimation Through Aggregation (META).” This method replaces traditional multivariate likelihood estimation with a procedure that requires estimating univariate processes only. This makes the estimation simpler, faster, and better behaved numerically. We prove that our estimation method is consistent and asymptotically normal distributed for the proposed framework. Finally, we present an empirical application focusing on the industrial production of several European countries.
Costing ‘healthy’ food baskets in Australia – a systematic review of food price and affordability monitoring tools, protocols and methods
Authors: Lewis Meron , Lee Amanda
Published: September 2016

Objective

To undertake a systematic review to determine similarities and differences in metrics and results between recently and/or currently used tools, protocols and methods for monitoring Australian healthy food prices and affordability.

Design

Electronic databases of peer-reviewed literature and online grey literature were systematically searched using the PRISMA approach for articles and reports relating to healthy food and diet price assessment tools, protocols, methods and results that utilised retail pricing.

Setting

National, state, regional and local areas of Australia from 1995 to 2015.

Subjects

Assessment tools, protocols and methods to measure the price of ‘healthy’ foods and diets.

Results

The search identified fifty-nine discrete surveys of ‘healthy’ food pricing incorporating six major food pricing tools (those used in multiple areas and time periods) and five minor food pricing tools (those used in a single survey area or time period). Analysis demonstrated methodological differences regarding: included foods; reference households; use of availability and/or quality measures; household income sources; store sampling methods; data collection protocols; analysis methods; and results.

Conclusions

‘Healthy’ food price assessment methods used in Australia lack comparability across all metrics and most do not fully align with a ‘healthy’ diet as recommended by the current Australian Dietary Guidelines. None have been applied nationally. Assessment of the price, price differential and affordability of healthy (recommended) and current (unhealthy) diets would provide more robust and meaningful data to inform health and fiscal policy in Australia. The INFORMAS ‘optimal’ approach provides a potential framework for development of these methods.
A cross-sectional assessment of food- and nutrient-based standards applied to British schoolchildren’s packed lunches
Authors: Evans Charlotte EL , Cade Janet E
Published: September 2016

Objective

In England, standards for school meals included both foods and nutrients until 2015. School policies for packed lunches are generally food based; research is needed to determine whether these are adequate or whether a small number of nutrients would potentially improve their quality.

Design

From dietary data obtained using a weighed dietary assessment tool, a diet quality score (DQS) for packed lunches was calculated using the number of standards met out of twenty-one (eight foods and thirteen nutrients). Multilevel regression analysis determined the foods and nutrients contributing to variation in the DQS.

Setting

Eighty-nine primary schools across the four regions of the UK (England, Wales, Scotland and Northern Ireland).

Subjects

British schoolchildren (n 1294), aged 8–9 years, taking a packed lunch.

Results

The optimal model included all eight foods and seven of the thirteen nutrients, explaining 72 % of the variance in DQS. Folate, Fe and vitamin C, together with the eight food groups, explained 70 % of DQS variation.

Conclusions

Ideally, policies for school packed lunches should include food-based standards plus recommendations based on a small number of nutrients.
Estimation of true height: a study in population-specific methods among young South African adults
Authors: Lahner Christen Renée , Kassier Susanna Maria , Veldman Frederick Johannes
Published: September 2016

Objective

To investigate the accuracy of arm-associated height estimation methods in the calculation of true height compared with stretch stature in a sample of young South African adults.

Design

A cross-sectional descriptive design was employed.

Setting

Pietermaritzburg, Westville and Durban, KwaZulu-Natal, South Africa, 2015.

Subjects

Convenience sample (N 900) aged 18–24 years, which included an equal number of participants from both genders (150 per gender) stratified across race (Caucasian, Black African and Indian).

Results

Continuous variables that were investigated included: (i) stretch stature; (ii) total armspan; (iii) half-armspan; (iv) half-armspan ×2; (v) demi-span; (vi) demi-span gender-specific equation; (vii) WHO equation; and (viii) WHO-adjusted equations; as well as categorization according to gender and race. Statistical analysis was conducted using IBM SPSS Statistics Version 21.0. Significant correlations were identified between gender and height estimation measurements, with males being anatomically larger than females (P<0·001). Significant differences were documented when study participants were stratified according to race and gender (P<0·001). Anatomical similarities were noted between Indians and Black Africans, whereas Caucasians were anatomically different from the other race groups. Arm-associated height estimation methods were able to estimate true height; however, each method was specific to each gender and race group.

Conclusions

Height can be calculated by using arm-associated measurements. Although universal equations for estimating true height exist, for the enhancement of accuracy, the use of equations that are race-, gender- and population-specific should be considered.
Descriptive figures for differences in parenting and infant night-time distress in the first three months of age
Authors: St James-Roberts Ian , Roberts Marion , Hovish Kimberly , Owen Charlie
Published: September 2016

Aim

To provide descriptive figures for infant distress and associated parenting at night in normal London home environments during the first three months of age.

Background

Most western infants develop long night-time sleep periods by four months of age. However, 30% of infants in many countries sleep for short periods and cry out on waking in the night: the most common type of infant sleep behaviour problem. Preventive interventions may help families and improve services. There is evidence that ‘limit-setting’ parenting, which is common in western cultures, supports the development of settled infant night-time behaviour. However, a recent review has challenged this and argued that this form of parenting risks distressing infants. This study describes limit-setting parenting as practiced in London, compares it with ‘infant-cued’ parenting and measures the associated infant distress.

Methods

Longitudinal infrared video, diary and questionnaire observations comparing a General-Community (n=101) group and subgroups with a Bed-Sharing (n=19) group on measures of infant and parenting behaviours at night.

Findings

General-Community parents took longer to detect and respond to infant waking and signalling, and to begin feeding, compared with the highly infant-cued care provided by Bed-Sharing parents. The average latency in General-Community parents’ responding to infant night-time waking was 3.5 min, during which infants fuss/cried for around 1 min. Compared with Bed-Sharing parenting, General-Community parenting was associated with increased infant distress of around 30 min/night at two weeks, reducing to 12 min/night by three months of age. However, differences in infant distress between General-Community subgroups adopting limit-setting versus infant-cued parenting were not large or statistically significant at any age. The figures provide descriptive evidence about limit-setting parenting which may counter some doubts about this form of parenting and help parents and professionals to make choices.
Anglicanism, Uhuru and Ujamaa: Anglicans in Tanzania and the Movement for Independence
Authors: Mndolwa Maimbo , Denis Philippe
Published: September 2016

The Anglican Church in Tanzania emerged from the work of the Universities’ Mission to Central Africa (UMCA) and the Australian Church Missionary Society (CMSA). The Anglican missions had goals which stood against colonialism and supported the victory of nationalism. Using archives and interviews as sources, this article considers the roles and reaction of the Anglican missions in the struggle for political independence in Tanganyika and Zanzibar, the effects of independence on the missions and the Church more broadly, and the responses of the missions to ujamaa in Tanzania.
Optical hydrogen absorption consistent with a bow shock around the hot Jupiter HD 189733 b
Authors: Cauley P. Wilson , Redfield Seth , Jensen Adam G. , Barman Travis , Endl Michael , Cochran William D.
Published: September 2016

Hot Jupiters, i.e., Jupiter-mass planets with orbital semi major axes of <10 stellar radii, can interact strongly with their host stars. If the planet is moving supersonically through the stellar wind, a bow shock will form ahead of the planet where the planetary magnetosphere slams into the the stellar wind or where the planetary outflow and stellar wind meet. Here we present high resolution spectra of the hydrogen Balmer lines for a single transit of the hot Jupiter HD 189733 b. Transmission spectra of the Balmer lines show strong absorption ~70 minutes before the predicted optical transit, implying a significant column density of excited hydrogen orbiting ahead of the planet. We show that a simple geometric bow shock model is able to reproduce the important features of the absorption time series while simultaneously matching the line profile morphology. Our model suggests a large planetary magnetic field strength of ~28 G. Follow-up observations are needed to confirm the pre-transit signal and investigate any variability in the measurement.
Ultraviolet and X-ray irradiance and flares from low-mass exoplanet host stars
Authors: France Kevin , Loyd R. O. Parke , Brown Alex
Published: September 2016

The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. High-energy photons (X-ray to NUV) from these stars regulate the atmospheric temperature profiles and photochemistry on orbiting planets, influencing the production of potential “biomarker” gases. We report first results from the MUSCLES Treasury Survey, a study of time-resolved UV and X-ray spectroscopy of nearby M and K dwarf exoplanet host stars. This program uses contemporaneous Hubble Space Telescope and Chandra (or XMM) observations to characterize the time variability of the energetic radiation field incident on the habitable zones planetary systems at d ≲ 20 pc. We find that all exoplanet host stars observed to date exhibit significant levels of chromospheric and transition region UV emission. M dwarf exoplanet host stars display 30–7000% UV emission line amplitude variations on timescales of minutes-to-hours. The relative flare/quiescent UV flux amplitudes on weakly active planet-hosting M dwarfs are comparable to active flare stars (e.g., AD Leo), despite their weak optical activity indices (e.g., Ca II H and K equivalent widths). We also detect similar UV flare behavior on a subset of our K dwarf exoplanet host stars. We conclude that strong flares and stochastic variability are common, even on “optically inactive” M dwarfs hosting planetary systems. These results argue that the traditional assumption of weak UV fields and low flare rates on older low-mass stars needs to be revised.
White-light continuum in stellar flares
Authors: Kowalski Adam F.
Published: September 2016

In this talk, we discuss the formation of the near-ultraviolet and optical continuum emission in M dwarf flares through the formation of a dense, heated chromospheric condensation. Results are used from a recent radiative-hydrodynamic model of the response of an M dwarf atmosphere to a high energy flux of nonthermal electrons. These models are used to infer the charge density and optical depth in continuum emitting flare layers from spectra covering the Balmer jump and optical wavelength regimes. Future modeling and observational directions are discussed.
Synthetic activity indicators for M-type dwarf stars
Authors: Wedemeyer Sven , Ludwig Hans-Günter
Published: September 2016

Here, we present a set of time-dependent 3D RMHD simulations of a M-dwarf star representative of AD Leo, which extend from the upper convection zone into the chromosphere. The 3D model atmospheres are characterized by a very dynamic and intermittent structure on small spatial and temporal scales and a wealth of physical processes, which by nature cannot be described by means of 1D static model atmospheres. Artificial observations of these models imply that a combination of complementary diagnostics such as Ca II lines and the continuum intensity from UV to millimeter wavelengths, probe various properties of the dynamics, thermal and magnetic structure of the photosphere and the chromosphere and thus provide measures of stellar activity, which can be compared to observations. The complicated magnetic field structure and its imprint in synthetic diagnostics may have important implications for the understanding and characterization of stellar activity and with it possibly for the evaluation of planetary habitability around active M-dwarf stars.
CARMENES: M dwarfs and their planets
Authors: Quirrenbach A. , Amado P.J. , Caballero J.A. , Mandel H. , Mundt R. , Reiners A. , Ribas I. , Seifert W. , Azzaro M. , Galadí D. ,   the CARMENES Consortium
Published: September 2016

CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) is a new instrument currently undergoing commissioning at the 3.5 m telescope of the Calar Alto Observatory. It has been constructed by a consortium of eleven Spanish and German institutions. The scientific goal of the project is a 600-night radial-velocity survey targeting 300 M dwarfs with sufficient precision to detect terrestrial planets in their habitable zones. The CARMENES instrument consists of two separate échelle spectrographs covering the wavelength range from 0.55 to 1.7 μm at a spectral resolution of R = 82,000, fed by fibers from the Cassegrain focus of the telescope. Both spectrographs are housed in a temperature-stabilized environment in vacuum tanks, to enable a long-term radial velocity precision of 1 m s−1. The wavelength calibration will be done with Th-Ne and U-Ne emission line lamps, and with Fabry-Pérot etalons.
Flares from ultracool L dwarfs with Kepler
Authors: Gizis John E. , Paudel Rishi , Williams Peter K. G. , Burgasser Adam J. , Schmidt Sarah J.
Published: September 2016

We report on our search for L dwarf flares using NASA's Kepler mission. Spectroscopically confirmedflares were detected with the original Kepler mission from an L1 dwarf stars. We discuss the physicalcharacteristics of these white light flares and compare them to M dwarf flares. For “habitable zone” planets, the apparent flare brightnesses would be comparable to the most powerful M dwarf flares. Weare monitoring more L dwarfs with the Kepler K2 mission. We discussthe prospect for more detections during the remainder of the K2 mission.
Fermi Large Area Telescope observation of high-energy solar flares: constraining emission scenarios
Authors: Omodei Nicola , Pesce-Rollins Melissa , Petrosian Vahè , Liu Wei , da Costa Fatima Rubio , Allafort Alice ,   for the Fermi-LAT collaboration
Published: September 2016

The Fermi Large Area Telescope (LAT) is the most sensitive instrument ever deployed in space for observing gamma-ray emission >100 MeV. This has also been demonstrated by its detection of quiescent gamma-ray emission from pions produced by cosmic-ray protons interacting in the solar atmosphere, and from cosmic-ray electron interactions with solar optical photons. The Fermi-LAT has also detected high-energy gamma-ray emission associated with GOES M-class and X-class solar flares, each accompanied by a coronal mass ejection and a solar energetic particle event, increasing the number of detected solar flares by almost a factor of 10 with respect to previous space observations. During the impulsive phase, gamma rays with energies up to several hundreds of MeV have been recorded by the LAT. Emission up to GeV energies lasting several hours after the flare has also been detected by the LAT. Of particular interest are the recent detections of three solar flares whose position behind the limb was confirmed by the STEREO satellites. While gamma-ray emission up to tens of MeV resulting from proton interactions has been detected before from occulted solar flares, the significance of these particular events lies in the fact that these are the first detections of >100 MeV gamma-ray emission from footpoint-occulted flares. We will present the Fermi-LAT, RHESSI and STEREO observations of these flares and discuss the various emission scenarios for these sources.
Stellar flares and the dark energy of CMEs
Authors: Drake Jeremy J. , Cohen Ofer , Garraffo Cecilia , Kashyap V.
Published: September 2016

Flares we observe on stars in white light, UV or soft X-rays are probably harbingers of coronal mass ejections (CMEs). If we use the Sun as a guide, large stellar flares will dissipate two orders of magnitude less X-ray radiative energy than the kinetic energy in the associated CME. Since coronal emission on active stars appears to be dominated by flare activity, CMEs pose a quandary for understanding the fraction of their energy budget stars can spend on magnetic activity. One answer is magnetic suppression of CMEs, in which the strong large-scale fields of active stars entrap and prevent CMEs unless their free energy exceeds a critical value. The CME-less flaring active region NOAA 2192 presents a possible solar analogue of this. Monster CMEs will still exist, and have the potential to ravage planetary atmospheres.
Solar flare soft X-ray spectra from Diogeness observations
Authors: Stȩślicki Marek , Sylwester Janusz , Sylwester Barbara , Szaforz Żaneta , Kordylewski Zbigniew , Płocieniak Stefan , Siarkowski Marek , Phillips Kenneth J. H.
Published: September 2016

Diogeness was an uncollimated scanning flat crystal spectrometer observing solar flare X-ray spectra in four narrow wavelength bands in the vicinity of Ca xix, S xv and Si xiii He-like line ‘triplets’ around 3.18 Å, 5.04 Å and 6.65 Å. In two of the spectral channels, emission lines around the Ca xix 3.178 Å resonance line were scanned in opposite directions, being diffracted from precisely adjusted identical Quartz crystals mounted on a common shaft in a so-called Dopplerometer (tachometer) configuration. Observations of solar X-ray spectra made by Diogeness provide a direct diagnostic information on plasma characteristics during the impulsive flare energy release. We present a sample of events which occurred during the Diogeness operation time from August 16, 2001 to September 17, 2001.
Response of chromospheric lines to different periodic non-thermal electron beams
Authors: Cheng Jianxia , Ding Mingde
Published: September 2016

Solar flares produce radiations in very broad wavelengths. Spectra can supply us abundant information about the local plasma, such as temperature, density, mass motion and so on. Strong chromospheric lines, like the most studied Hα and Ca II 8542 Å lines are formed under conditions of departures from local thermodynamic equilibrium in the lower atmosphere subject to flare heating. Understanding how these lines are formed is very useful for us to correctly interpret the observations. In this paper, we try to figure out the response of chromospheric lines heated by different periodic non-thermal electron beams. Our results are based on radiative hydrodynamic simulations. We vary the periods of electron beam injection from 1.25 s to 20 s. We compare the response times to different heating parameters. Possible explanations are discussed.
Solar extreme ultraviolet (EUV) flare observations and findings from the Solar Dynamics Observatory (SDO) EUV Variability Experiment (EVE)
Authors: Woods Thomas N. , Eparvier Francis G. , Mason James P.
Published: September 2016

New solar soft X-ray (SXR) and extreme ultraviolet (EUV) irradiance observations from NASA Solar Dynamics Observatory (SDO) EUV Variability Experiment (EVE) provide full coverage from 0.1 to 106 nm and continuously at a cadence of 10 seconds for spectra at 0.1 nm resolution. These observations during flares can usually be decomposed into four distinct characteristics: impulsive phase, gradual phase, coronal dimming, and EUV late phase. Over 6000 flares have been observed during the SDO mission; some flares show all four phases, and some only show the gradual phase. The focus is on the newer results about the EUV late phase and coronal dimming and its relationship to coronal mass ejections (CMEs). These EVE flare measurements are based on observing the sun-as-a-star, so these results could exemplify stellar flares. Of particular interest is that new coronal dimming measurements of stars could be used to estimate mass and velocity of stellar CMEs.
Observations and modeling of the ultraviolet emission of solar flares
Authors: Mikuła Katarzyna , Berlicki Arkadiusz , Heinzel Petr
Published: September 2016

In this paper we present the method of using far UV spectra of the flare observed by Interface Region Imaging Spectrograph (IRIS) for determination of the contribution of the continuum emission to the total UV radiation observed e.g. by SDO in 1600 Å channel. In our method the Si IV (1402.77 Å) line observed by IRIS is used as a proxy of C IV line emission contained in SDO/AIA UV images. Determined intensity of the flare continuum emission can be used to study the physics of the flare heated chromosphere and for better understanding of the emission mechanisms.
Discovery of superflares
Authors: Nogami Daisaku
Published: September 2016

We have discovered 1547 ‘superflares’ on about 279 G-type main-sequence stars by using the Kepler-spacecraft data of Q0-Q6. ‘Superflares’ mean flares that radiate total energy 10 times or more larger than that of the largest flare in the Sun ever recorded. We here briefly review our current understandings on superflares and superflare stars obtained by analyzing the Kepler data and follow-up high dispersion spectra.
Characterization of X-ray flare properties of AB Dor
Authors: Lalitha S.
Published: September 2016

The strong similarities between the flares observed on the Sun and in low mass stars has raised question regarding dynamo in these stars. Using the Sun as a prototype, one may be able to address this. In this paper, we present an analysis of 30 intense X-ray flares observed from AB Dor. These flares detected in XMM-Newton data show a rapid rise (500-3000 s) and a slow decay (1000-6000 s). Our studies suggest that the scaling law between the flare peak emission measure and the flare peak temperature for all the flares observed on AB Dor is very similar to the relationship followed by solar flares. Furthermore, we obtain the frequency distribution of flare energies which is a crucial diagnostic to calculate the overall energy residing in a flare. Our results of this study indicate that the large flare (1033 ≤ E ≤ 1034 erg) may not contribute to the heating of the corona.
White-light continuum emission from a solar flare and plage
Authors: Berlicki Arkadiusz , Awasthi Arun Kumar , Heinzel Petr , Sobotka Michal
Published: September 2016

Observations of flare emissions in the optical continuum are very rare. Therefore, the analysis of such observations is useful and may contribute to our understanding of the flaring chromosphere and photosphere. We study the white light continuum emission observed during the X6.9 flare. This emission comes not only from the flare ribbons but also form the nearby plage area. The main aim of this work is to disentangle the flare and plage (facula) emission. We analyzed the spatial, spectral and temporal evolution of the flare and plage properties by analyzing multi-wavelength observations. We study the morphological correlation of the white-light continuum emission observed with different instruments. We found that some active region areas which produce the continuum emission correspond rather to plages than to the flare kernels. We showed that in some cases the continuum emission from the WL flare kernels is very similar to the continuum emission of faculae.
The frequency of stellar X-ray flares from a large-scale XMM-Newton sample
Authors: Pye John P. , Rosen Simon R.
Published: September 2016

We present estimates of cool-star X-ray flare rates determined from the XMM-Tycho survey (Pyeet al. 2015, A&A, 581, A28), and compare them with previously published values for the Sun and for other stellar EUV and white-light samples. We demonstrate the importance of applying appropriate corrections, especially in regard to the total, effective size of the stellar sample. Our results are broadly consistent with rates reported in the literature for Kepler white-light flares from solar-type stars, and with extrapolations of solar flare rates, indicating the potential of stellar X-ray flare observations to address issues such as ‘space weather’ in exoplanetary systems and our own solar system.
Broadband capacitively grounded coplanar to coupled microstrip transition for planar microwave photonic components
Authors: Hadjloum Massinissa , El Gibari Mohammed , Li Hongwu , Daryoush Afshin S.
Published: September 2016

Broadband transitions are presented in this paper for capacitively grounded coplanar waveguide to coupled microstrip (CMS) lines. These transitions are realized on both thick Rogers RO3003 substrate (thickness of 10 mils) and a thin benzocyclobutene (BCB) polymer film (thickness of 20 µm). A flat bandwidth of 4–20 GHz and 3.2 to over 40 GHz are measured for the RO3003 and BCB polymer substrates, respectively. These performances are obtained without making via-hole in the substrate or patterning the bottom ground plane, which makes this broadband transition easier to fabricate compared with the via-hole-based grounded CPW–CMS transitions.
Effects ofIlex paraguariensis(yerba mate) on the hypothalamic signalling of insulin and leptin and liver dysfunction in adult rats overfed during lactation
Authors: Conceição E. P. S. , Kaezer A. R. , Peixoto-Silva N. , Felzenszwalb I. , de Oliveira E. , Moura E. G. , Lisboa P. C.
Published: September 2016

Ilex paraguariensis(yerba mate) has a beneficial effect in the management of obesity. Here, we studied the effects of yerba mate on hypothalamic changes in leptin and insulin signalling, oxidative stress and liver morphology and metabolism in postnatal early overfeeding (EO) Wistar rats. To induce EO, the litter size was reduced to three pups per dam, and litters with 10 pups per dam were used as a control (10 litters each). On postnatal day (PN) 150, EO offspring were subdivided into EO and EO+mate groups (10 animals each), which were treated with water or mate tea [1 g/kg body weight (BW)/day, by gavage], respectively, for 30 days. The C offspring received water. On PN180, yerba mate treatment prevented BW gain and reduced total body fat, visceral fat and food intake in comparison with the EO group. Leptin and insulin signalling in the hypothalamus measured by Western blotting was reduced only in the EO group. Yerba mate treatment had a greater impact on insulin signalling normalization. In the liver, yerba mate treatment normalized antioxidant enzyme activities and, consequently, decreased lipid peroxidation, determined by malondialdehyde content. In addition, the steatosis level and the liver triglyceride content were also restored. Thus, for the first time, yerba mate was demonstrated to increase antioxidant defences and improve liver metabolism in adult rats that were overfed during lactation, possibly through improvements in the hypothalamic action of insulin. These findings may be important for the treatment of obesity-related disorders.
Terahertz time-gated spectral imaging for content extraction through layered structures
Authors: Redo-Sanchez Albert , Heshmat Barmak , Aghasi Alireza , Naqvi Salman , Zhang Mingjie , Romberg Justin , Raskar Ramesh
Published: September 2016

Spatial resolution, spectral contrast and occlusion are three major bottlenecks for non-invasive inspection of complex samples with current imaging technologies. We exploit the sub-picosecond time resolution along with spectral resolution provided by terahertz time-domain spectroscopy to computationally extract occluding content from layers whose thicknesses are wavelength comparable. The method uses the statistics of the reflected terahertz electric field at subwavelength gaps to lock into each layer position and then uses a time-gated spectral kurtosis to tune to highest spectral contrast of the content on that specific layer. To demonstrate, occluding textual content was successfully extracted from a packed stack of paper pages down to nine pages without human supervision. The method provides over an order of magnitude enhancement in the signal contrast and can impact inspection of structural defects in wooden objects, plastic components, composites, drugs and especially cultural artefacts with subwavelength or wavelength comparable layers.
Plasmonic twinned silver nanoparticles with molecular precision
Authors: Yang Huayan , Wang Yu , Chen Xi , Zhao Xiaojing , Gu Lin , Huang Huaqi , Yan Juanzhu , Xu Chaofa , Li Gang , Wu Junchao , Edwards Alison J. , Dittrich Birger , Tang Zichao , Wang Dongdong , Lehtovaara Lauri , Häkkinen Hannu , Zheng Nanfeng
Published: September 2016

Determining the structures of nanoparticles at atomic resolution is vital to understand their structure–property correlations. Large metal nanoparticles with core diameter beyond 2 nm have, to date, eluded characterization by single-crystal X-ray analysis. Here we report the chemical syntheses and structures of two giant thiolated Ag nanoparticles containing 136 and 374 Ag atoms (that is, up to 3 nm core diameter). As the largest thiolated metal nanoparticles crystallographically determined so far, these Ag nanoparticles enter the truly metallic regime with the emergence of surface plasmon resonance. As miniatures of fivefold twinned nanostructures, these structures demonstrate a subtle distortion within fivefold twinned nanostructures of face-centred cubic metals. The Ag nanoparticles reported in this work serve as excellent models to understand the detailed structure distortion within twinned metal nanostructures and also how silver nanoparticles can span from the molecular to the metallic regime.
Analyses of point mutation repair and allelic heterogeneity generated by CRISPR/Cas9 and single-stranded DNA oligonucleotides
Authors: Bialk Pawel , Sansbury Brett , Rivera-Torres Natalia , Bloh Kevin , Man Dula , Kmiec Eric B.
Published: September 2016

The repair of a point mutation can be facilitated by combined activity of a single-stranded oligonucleotide and a CRISPR/Cas9 system. While the mechanism of action of combinatorial gene editing remains to be elucidated, the regulatory circuitry of nucleotide exchange executed by oligonucleotides alone has been largely defined. The presence of the appropriate CRISPR/Cas9 system leads to an enhancement in the frequency of gene editing directed by single-stranded DNA oligonucleotides. While CRISPR/Cas9 executes double-stranded DNA cleavage efficiently, closure of the broken chromosomes is dynamic, as varying degrees of heterogeneity of the cleavage products appear to accompany the emergence of the corrected base pair. We provide a detailed analysis of allelic variance at and surrounding the target site. In one particular case, we report sequence alteration directed by a distinct member of the same gene family. Our data suggests that single-stranded DNA molecules may influence DNA junction heterogeneity created by CRISPR/Cas9.
Direct observation of dynamic modes excited in a magnetic insulator by pure spin current
Authors: Demidov V. E. , Evelt M. , Bessonov V. , Demokritov S. O. , Prieto J. L. , Muñoz M. , Ben Youssef J. , Naletov V. V. , de Loubens G. , Klein O. , Collet M. , Bortolotti P. , Cros V. , Anane A.
Published: September 2016

Excitation of magnetization dynamics by pure spin currents has been recently recognized as an enabling mechanism for spintronics and magnonics, which allows implementation of spin-torque devices based on low-damping insulating magnetic materials. Here we report the first spatially-resolved study of the dynamic modes excited by pure spin current in nanometer-thick microscopic insulating Yttrium Iron Garnet disks. We show that these modes exhibit nonlinear self-broadening preventing the formation of the self-localized magnetic bullet, which plays a crucial role in the stabilization of the single-mode magnetization oscillations in all-metallic systems. This peculiarity associated with the efficient nonlinear mode coupling in low-damping materials can be among the main factors governing the interaction of pure spin currents with the dynamic magnetization in high-quality magnetic insulators.
miR-24, miR-30b and miR-142-3p interfere with antigen processing and presentation by primary macrophages and dendritic cells
Authors: Naqvi Afsar Raza , Fordham Jezrom B. , Ganesh Balaji , Nares Salvador
Published: September 2016

Antigen uptake, processing and presentation by antigen presenting cells (APCs) are tightly coupled processes which consequently lead to the activation of innate and adaptive immune responses. However, the regulatory role of microRNA (miRNAs) in these critical pathways is poorly understood. In this study, we show that overexpression of miR-24, miR-30b and miR-142-3p attenuates uptake and processing of soluble antigen ovalbumin (Ova) in primary human macrophages and dendritic cells. MiRNA mimic transfected APCs exhibit defects in antigen presentation (Ova and CMV antigen) to CD4+ T-cells leading to reduced cell proliferation. Using transgenic OT-II mice we demonstrated that this impairment in T-cell proliferation is specific to antigen provided i.e., Ova. Further, human T-cells co-cultured with miRNA transfected dendritic cells secrete low levels of T helper (Th)-1 polarization associated cytokines. Analysis of molecules regulating APC and T-cell receptor interaction shows miRNA-mediated induced expression of Programmed Death-Ligand 1 (PD-L1) which inhibits T-cell proliferation. Blocking PD-L1 with antibodies rescues miRNA-mediated inhibition of T cell priming by DCs. These results uncover regulatory functions of miR-24, miR-30b and miR-142-3p in pairing innate and adaptive components of immunity.
Non-linear quantum-classical scheme to simulate non-equilibrium strongly correlated fermionic many-body dynamics
Authors: Kreula J. M. , Clark S. R. , Jaksch D.
Published: September 2016

We propose a non-linear, hybrid quantum-classical scheme for simulating non-equilibrium dynamics of strongly correlated fermions described by the Hubbard model in a Bethe lattice in the thermodynamic limit. Our scheme implements non-equilibrium dynamical mean field theory (DMFT) and uses a digital quantum simulator to solve a quantum impurity problem whose parameters are iterated to self-consistency via a classically computed feedback loop where quantum gate errors can be partly accounted for. We analyse the performance of the scheme in an example case.
Predicting the synergy of multiple stress effects
Authors: Liess Matthias , Foit Kaarina , Knillmann Saskia , Schäfer Ralf B. , Liess Hans-Dieter
Published: September 2016

Toxicants and other, non-chemical environmental stressors contribute to the global biodiversity crisis. Examples include the loss of bees and the reduction of aquatic biodiversity. Although non-compliance with regulations might be contributing, the widespread existence of these impacts suggests that for example the current approach of pesticide risk assessment fails to protect biodiversity when multiple stressors concurrently affect organisms. To quantify such multiple stress effects, we analysed all applicable aquatic studies and found that the presence of environmental stressors increases individual sensitivity to toxicants (pesticides, trace metals) by a factor of up to 100. To predict this dependence, we developed the “Stress Addition Model” (SAM). With the SAM, we assume that each individual has a general stress capacity towards all types of specific stress that should not be exhausted. Experimental stress levels are transferred into general stress levels of the SAM using the stress-related mortality as a common link. These general stress levels of independent stressors are additive, with the sum determining the total stress exerted on a population. With this approach, we provide a tool that quantitatively predicts the highly synergistic direct effects of independent stressor combinations.
The non-equilibrium phase diagrams of flow-induced crystallization and melting of polyethylene
Authors: Wang Zhen , Ju Jianzhu , Yang Junsheng , Ma Zhe , Liu Dong , Cui Kunpeng , Yang Haoran , Chang Jiarui , Huang Ningdong , Li Liangbin
Published: September 2016

Combining extensional rheology with in-situ synchrotron ultrafast x-ray scattering, we studied flow-induced phase behaviors of polyethylene (PE) in a wide temperature range up to 240 °C. Non-equilibrium phase diagrams of crystallization and melting under flow conditions are constructed in stress-temperature space, composing of melt, non-crystalline δ, hexagonal and orthorhombic phases. The non-crystalline δ phase is demonstrated to be either a metastable transient pre-order for crystallization or a thermodynamically stable phase. Based on the non-equilibrium phase diagrams, nearly all observations in flow-induced crystallization (FIC) of PE can be well understood. The interplay of thermodynamic stabilities and kinetic competitions of the four phases creates rich kinetic pathways for FIC and diverse final structures. The non-equilibrium flow phase diagrams provide a detailed roadmap for precisely processing of PE with designed structures and properties.
Multifunctional Polymer-Based Graphene Foams with Buckled Structure and Negative Poisson’s Ratio
Authors: Dai Zhaohe , Weng Chuanxin , Liu Luqi , Hou Yuan , Zhao Xuanliang , Kuang Jun , Shi Jidong , Wei Yueguang , Lou Jun , Zhang Zhong
Published: September 2016

In this study, we report the polymer-based graphene foams through combination of bottom-up assembly and simple triaxially buckled structure design. The resulting polymer-based graphene foams not only effectively transfer the functional properties of graphene, but also exhibit novel negative Poisson’s ratio (NPR) behaviors due to the presence of buckled structure. Our results show that after the introduction of buckled structure, improvement in stretchability, toughness, flexibility, energy absorbing ability, hydrophobicity, conductivity, piezoresistive sensitivity and crack resistance could be achieved simultaneously. The combination of mechanical properties, multifunctional performance and unusual deformation behavior would lead to the use of our polymer-based graphene foams for a variety of novel applications in future such as stretchable capacitors or conductors, sensors and oil/water separators and so on.
Rate of biological invasions is lower in coastal marine protected areas
Authors: Ardura A. , Juanes F. , Planes S. , Garcia-Vazquez E.
Published: September 2016

Marine biological invasions threaten biodiversity worldwide. Here we explore how Marine Protected areas, by reducing human use of the coast, confer resilience against the introduction of non-indigenous species (NIS), using two very different Pacific islands as case studies for developing and testing mathematical models. We quantified NIS vectors and promoters on Vancouver (Canada) and Moorea (French Polynesia) islands, sampled and barcoded NIS, and tested models at different spatial scales with different types of interaction among vectors and between marine protection and NIS frequency. In our results NIS were negatively correlated with the dimension of the protected areas and the intensity of the protection. Small to medium geographical scale protection seemed to be efficient against NIS introductions. The likely benefit of MPAs was by exclusion of aquaculture, principally in Canada. These results emphasize the importance of marine protected areas for biodiversity conservation, and suggest that small or medium protected zones would confer efficient protection against NIS introduction.
Polysialic acid sustains cancer cell survival and migratory capacity in a hypoxic environment
Authors: Elkashef Sara M. , Allison Simon J. , Sadiq Maria , Basheer Haneen A. , Ribeiro Morais Goreti , Loadman Paul M. , Pors Klaus , Falconer Robert A.
Published: September 2016

Polysialic acid (polySia) is a unique carbohydrate polymer expressed on the surface of NCAM (neuronal cell adhesion molecule) in a number of cancers where it modulates cell-cell and cell-matrix adhesion, migration, invasion and metastasis and is strongly associated with poor clinical prognosis. We have carried out the first investigation into the effect of polySia expression on the behaviour of cancer cells in hypoxia, a key source of chemoresistance in tumours. The role of polysialylation and associated tumour cell migration and cell adhesion were studied in hypoxia, along with effects on cell survival and the potential role of HIF-1. Our findings provide the first evidence that polySia expression sustains migratory capacity and is associated with tumour cell survival in hypoxia. Initial mechanistic studies indicate a potential role for HIF-1 in sustaining polySia-mediated migratory capacity, but not cell survival. These data add to the growing body of evidence pointing to a crucial role for the polysialyltransferases (polySTs) in neuroendocrine tumour progression and provide the first evidence to suggest that polySia is associated with an aggressive phenotype in tumour hypoxia. These results have significant potential implications for polyST inhibition as an anti-metastatic therapeutic strategy and for targeting hypoxic cancer cells.
A self-inducible heterologous protein expression system in Escherichia coli
Authors: Briand L. , Marcion G. , Kriznik A. , Heydel J. M. , Artur Y. , Garrido C. , Seigneuric R. , Neiers F.
Published: September 2016

Escherichia coli is an important experimental, medical and industrial cell factory for recombinant protein production. The inducible lac promoter is one of the most commonly used promoters for heterologous protein expression in E. coli. Isopropyl-β-D-thiogalactoside (IPTG) is currently the most efficient molecular inducer for regulating this promoter’s transcriptional activity. However, limitations have been observed in large-scale and microplate production, including toxicity, cost and culture monitoring. Here, we report the novel SILEX (Self-InducibLe Expression) system, which is a convenient, cost-effective alternative that does not require cell density monitoring or IPTG induction. We demonstrate the broad utility of the presented self-inducible method for a panel of diverse proteins produced in large amounts. The SILEX system is compatible with all classical culture media and growth temperatures and allows protein expression modulation. Importantly, the SILEX system is proven to be efficient for protein expression screening on a microplate scale.