bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementation and Comparison of Acoustic Travel-Time Measurement Procedures for the Solar Dynamics Observatory/Helioseismic and Magnetic Imager Time – Distance Helioseismology Pipeline
Authors: Couvidat S. , Zhao J. , Birch A. C. , Kosovichev A. G. , Duvall T. L. , Parchevsky K. , Scherrer P. H.
Published: March 2012

The Helioseismic and Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO) satellite is designed to produce high-resolution Doppler-velocity maps of oscillations at the solar surface with high temporal cadence. To take advantage of these high-quality oscillation data, a time – distance helioseismology pipeline (Zhao et al., Solar Phys. submitted, 2010) has been implemented at the Joint Science Operations Center (JSOC) at Stanford University. The aim of this pipeline is to generate maps of acoustic travel times from oscillations on the solar surface, and to infer subsurface 3D flow velocities and sound-speed perturbations. The wave travel times are measured from cross-covariances of the observed solar oscillation signals. For implementation into the pipeline we have investigated three different travel-time definitions developed in time – distance helioseismology: a Gabor-wavelet fitting (Kosovichev and Duvall, SCORE’96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997), a minimization relative to a reference cross-covariance function (Gizon and Birch, Astrophys. J.571, 966, 2002), and a linearized version of the minimization method (Gizon and Birch, Astrophys. J.614, 472, 2004). Using Doppler-velocity data from the Michelson Doppler Imager (MDI) instrument onboard SOHO, we tested and compared these definitions for the mean and difference travel-time perturbations measured from reciprocal signals. Although all three procedures return similar travel times in a quiet-Sun region, the method of Gizon and Birch (Astrophys. J.614, 472, 2004) gives travel times that are significantly different from the others in a magnetic (active) region. Thus, for the pipeline implementation we chose the procedures of Kosovichev and Duvall (SCORE’96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997) and Gizon and Birch (Astrophys. J.571, 966, 2002). We investigated the relationships among these three travel-time definitions, their sensitivities to fitting parameters, and estimated the random errors that they produce.
The Solar Dynamics Observatory (SDO)
Authors: Pesnell W. Dean , Thompson B. J. , Chamberlin P. C.
Published: March 2012

The Solar Dynamics Observatory (SDO) was launched on 11 February 2010 at 15:23 UT from Kennedy Space Center aboard an Atlas V 401 (AV-021) launch vehicle. A series of apogee-motor firings lifted SDO from an initial geosynchronous transfer orbit into a circular geosynchronous orbit inclined by 28° about the longitude of the SDO-dedicated ground station in New Mexico. SDO began returning science data on 1 May 2010. SDO is the first space-weather mission in NASA’s Living With a Star (LWS) Program. SDO’s main goal is to understand, driving toward a predictive capability, those solar variations that influence life on Earth and humanity’s technological systems. The SDO science investigations will determine how the Sun’s magnetic field is generated and structured, how this stored magnetic energy is released into the heliosphere and geospace as the solar wind, energetic particles, and variations in the solar irradiance. Insights gained from SDO investigations will also lead to an increased understanding of the role that solar variability plays in changes in Earth’s atmospheric chemistry and climate. The SDO mission includes three scientific investigations (the Atmospheric Imaging Assembly (AIA), Extreme Ultraviolet Variability Experiment (EVE), and Helioseismic and Magnetic Imager (HMI)), a spacecraft bus, and a dedicated ground station to handle the telemetry. The Goddard Space Flight Center built and will operate the spacecraft during its planned five-year mission life; this includes: commanding the spacecraft, receiving the science data, and forwarding that data to the science teams. The science investigations teams at Stanford University, Lockheed Martin Solar Astrophysics Laboratory (LMSAL), and University of Colorado Laboratory for Atmospheric and Space Physics (LASP) will process, analyze, distribute, and archive the science data. We will describe the building of SDO and the science that it will provide to NASA.
Imprecise probabilistic query answering using measures of ignorance and degree of satisfaction
Authors: Yue Anbu , Liu Weiru , Hunter Anthony
Published: March 2012

In conditional probabilistic logic programming, given a query, the two most common forms for answering the query are either a probability interval or a precise probability obtained by using the maximum entropy principle. The former can be noninformative (e.g., interval [0, 1]) and the reliability of the latter is questionable when the priori knowledge is imprecise. To address this problem, in this paper, we propose some methods to quantitatively measure if a probability interval or a single probability is sufficient for answering a query. We first propose an approach to measuring the ignorance of a probabilistic logic program with respect to a query. The measure of ignorance (w.r.t. a query) reflects how reliable a precise probability for the query can be and a high value of ignorance suggests that a single probability is not suitable for the query. We then propose a method to measure the probability that the exact probability of a query falls in a given interval, e.g., a second order probability. We call it the degree of satisfaction. If the degree of satisfaction is high enough w.r.t. the query, then the given interval can be accepted as the answer to the query. We also prove our measures satisfy many properties and we use a case study to demonstrate the significance of the measures.
Development of a core set of SSR markers for the characterization of Gossypium germplasm
Authors: Yu John Z. , Fang David D. , Kohel Russell J. , Ulloa Mauricio , Hinze Lori L. , Percy Richard G. , Zhang Jinfa , Chee Peng , Scheffler Brian E. , Jones Don C.
Published: March 2012

Molecular markers such as simple sequence repeats (SSR) are a useful tool for characterizing genetic diversity of Gossypium germplasm. Genetic profiles by DNA fingerprinting of cotton accessions can only be compared among different collections if a common set of molecular markers are used by different laboratories and/or research projects. Herein, we propose and report a core set of 105 SSR markers with wide genome coverage of at least four evenly distributed markers per chromosome for the 26 tetraploid cotton chromosomes. The core marker set represents the efforts of ten research groups involved in marker development, and have been systematically evaluated for DNA polymorphism on the 12 genotypes belonging to six Gossypium species [known collectively as the cotton marker database (CMD) panel]. A total of 35 marker bins in triplex sets were arranged from the 105 markers that were each labeled with one of the three fluorescent dyes (FAM, HEX, and NED). Results from this study indicated that the core marker set was robust in revealing DNA polymorphism either between and within species. Average value of polymorphism information content (PIC) among the CMD panel was 0.65, and that within the cultivated cotton species Gossypium hirsutum was 0.29. Based on the similarity matrix and phylogenetic analysis of the CMD panel, the core marker set appeared to be sufficient in characterizing the diversity within G. hirsutum and other Gossypium species. The portability of this core marker set would facilitate the systematic characterization and the simultaneous comparison among various research efforts involved in genetic diversity analysis and germplasm resource preservation.
Paleontology and Evolution in the News
Authors: Horenstein Sidney
Published: March 2012

This paper is a review of recent media publications and journal articles about evolution and paleontology.
Digestion characteristics of two forms of preserved lucerne forage fed to mature horses
Authors: Waldron L. A. , Thomas D. G. , Pryor I.
Published: March 2012

A trial was conducted, using 12 mature thoroughbred horses as a cross-over design, to compare the water and energy intake and the digestibility of dry lucerne chaff (LC) against a controlled fermented lucerne (CFL) product (HNF Fiber®; Fiber Fresh Feeds Ltd, Reporoa, New Zealand). Significant (P < 0.05) increases in dry matter intake (20%), energy intake (20%), retained energy (32%) and digestible energy (22%) were observed for the CFL compared to the LC. In a concurrent small scale study within the trial, numeric improvements in water intake (18%) for the CFL were recorded. The results demonstrated that the standard reference values underestimate the digestibility and nutritional contribution made by CFL when fed to horses, and that this type of forage has increased nutritional benefits.
The hidden coloniality at the parasitic stage in Peltogaster reticulatus (Crustacea: Rhizocephala)
Authors: Isaeva Valeria V. , Akhmadieva Anna V. , Shukalyuk Andrey I.
Published: March 2012

Upon infesting the hermit crab Pagurus proximus the parasitic barnacle Peltogaster reticulatus typically forms a single externa on each host. In vivo, histological and histochemical study revealed that most P. reticulatus with a single mature externa also exhibited three or four primordial externae and several buds of earlier developmental stages. It is shown that stolon buds and primordial externae in P. reticulatus internae intensively express alkaline phosphatase activity, the classical histochemical marker for mammalian embryonic stem and primary germ cells. Ovaries of the most developed primordial externae were filled with growing oocytes, so the process of oogenesis begins in the externa rudiments of P. reticulatus before the externae appear on the surface of the host body. Since the interna, which is connected to the mature externa, also integrated three or four additional primordial externae and several earlier buds, P. reticulatus, a non-colonial species based on the common presence of a single externa in each host, appears to have a hidden colonial organization at the parasitic stage of its life cycle.
Reproductive development versus estimated age and size in a wild Mediterranean population ofOctopus vulgaris(Cephalopoda: Octopodidae)
Authors: Cuccu Danila , Mereu Marco , Cau Alessandro , Pesci Paola , Cau Angelo
Published: March 2012

First investigation on the relationship between reproductive development and estimated age/size in a wild population ofOctopus vulgariswas performed in the Sardinian waters (central western Mediterranean Sea) in order to have a useful tool for integral fishing management in the area. Full sexual maturity was registered from April to August for females with a peak in summer whereas for males it was observed all year round. Size at maturity was 320 g for males (70 mm dorsal mantle length (ML)) and 520 g for females (120 mm ML). From 61 to 465 and from 80 to 390 daily growth increments were counted on the lateral wall of the upper beak, respectively in males and females, obtaining a positive relationship between estimated age and size of the specimens. The sexual maturation was primarily size-dependent with a secondary role played by the age especially in males. The estimated age of 390 and 465 days respectively of the largest female (4661 g) and male (5344 g) as well as that of two males at the end of their lives (‘spent’) of 310 and 420 days old, have suggested a lifecycle of about 1 year for both genders.
Brittle stars (Echinodermata: Ophiuroidea) from seamounts in the Andaman Sea (Indian Ocean): first account, with descriptions of new species
Authors: Stöhr Sabine , Sautya Sabyasachi , Ingole Baban
Published: March 2012

For the first time, brittle stars were collected on two seamounts in the Andaman Back-arc Basin. Of the six species, two were new to science and are described herein asOphioleuce longispinumsp. nov. andOphiophyllum minimumsp. nov., in the family Ophiuridae, subfamilies Ophioleucinae and Ophiurinae, respectively. Skeletal details were studied and documented by scanning electron microscopy. Morphological similarities between related species are discussed in detail.Ophioleuce longispinumsp. nov. is particularly interesting, because it combines characters typical for its genus with those otherwise only known fromOphiophyllum, such as a limpet-like disc, a fringe of marginal disc papillae or spines, and a paddle-like modified lower arm spine. The remaining species,Astrophiuracf.tiki,Ophiactis perplexa,Ophiolimna antarcticaand an unidentifiedOphiura, are new records for the Andaman Sea.
Relative growth and reproduction in Achelous spinicarpus (Crustacea: Portunidae) on the south-eastern continental shelf of Brazil
Authors: Pardal-Souza André L. , Pinheiro Marcelo A.A.
Published: March 2012

This investigation aimed to study the relative growth, morphological sexual maturity and fecundity of the swimming crab Achelous spinicarpus in a tropical region, on the south-eastern continental shelf of Brazil (25°S). Biometry of all specimens was conducted, including measurements of the cephalothorax, cheliped, abdomen and gonopods. Relative growth was described based on the equation for allometry (y = axb), and size at sexual maturity was determined from inflections in relations involving the cheliped, gonopods (males), and abdomen (females), as dependent variables, related to the cephalothorax width (independent variable). Fecundity was estimated by the gravimetric method. The relations of the length of the chelar propodus and carpal spine to the carapace width without the lateral spines (CW) showed positive allometry in both sexes, with a significant variation in the constant ‘b’ for males between the developmental stages (juvenile and adult) and the size at maturity estimated at 37 mm CW. In females, the abdomen was most appropriate for the estimate of morphological maturity, which occurred at a smaller size (32 mm CW), with a change in the growth pattern between the stages, passing from isometric (juveniles) to positive allometric (adults). The gonopods also showed different growth rates between developmental stages, in synchrony with the variables of the cheliped. Mean fecundity for the species was 53,984 eggs, with a positive correlation between the number of eggs exteriorized and the size of the female; the equations allowed interconversion between these variables, due to the adjustment of the power function (r2 ≥ 86%).
Shades of Grey: Soft Law and the Validity of Public International Law
Authors: ELLIS JAYE
Published: March 2012

Soft law is often seen as a way to overcome certain problems of legitimacy in international law, notably the weaknesses of a voluntaristic conception of international law's validity. Other perceived benefits of soft law include flexibility, speed of adoption and modification, and even effectiveness. Yet, soft law is seen by others as a threat to law, because it effaces the border between law and politics. This paper explores different approaches to the boundary between law and not-law that seek both to maintain this boundary and to reconceptualize it in a way that better anchors the validity of international legal rules.
Women and Substance Abuse: Health Considerations and Recommendations
Authors: Ait-Daoud Nassima , Bashir Mudhasir
Published: March 2012

There has been growing evidence in recent years of the importance of gender specific issues in the addiction field. This paper explores specific problems and including specific health consequences faced by women who drink or use drugs. We describe helpful screening tools that can be used in the primary care setting and offer an understanding of some of the barriers preventing women from seeking help. This article also provides guidance on the best pharmacotherapy and psychological interventions that can be used to help women recover from their addiction.
Attitudes Toward Borderline Personality Disorder: A Survey of 706 Mental Health Clinicians
Authors: Black Donald W. , Pfohl Bruce , Blum Nancee , McCormick Brett , Allen Jeff , North Carol S. , Phillips Katharine A. , Robins Clive , Siever Larry , Silk Kenneth R. , Williams Janet B.W. , Zimmerman Mark
Published: March 2012

Objective

We sought to determine attitudes toward patients with borderline personality disorder (BPD) among mental health clinicians at nine academic centers in the United States.

Methods

A self-report questionnaire was distributed to 706 mental health clinicians, including psychiatrists, psychiatry residents, social workers, nurses, and psychologists.

Results

The study showed that most clinicians consider BPD a valid diagnosis, although nearly half reported that they preferred to avoid these patients. The clinician's occupational subgroup was significantly related to attitude. Staff nurses had the lowest self-ratings on overall caring attitudes, while social workers had the highest. Social workers and psychiatrists had the highest ratings on treatment optimism. Social workers and psychologists were most optimistic about psychotherapy effectiveness, while psychiatrists were most optimistic about medication effectiveness. Staff nurses had the lowest self-ratings on empathy toward patients with BPD and treatment optimism.

Discussion

Negative attitudes persist among clinicians toward BPD, but differ among occupational subgroups. Overall, caring attitudes, empathy, and treatment optimism were all higher among care providers who had cared for a greater number of BPD patients in the past 12 months.

Conclusion

These findings hold important implications for clinician education and coordination of care for patients with BPD.
Self-Harm in Prisoners
Authors: Carli Vladimir , Mandelli Laura , Poštuvan Vita , Roy Alec , Bevilacqua Laura , Cesaro Caterina , Baralla Francesca , Marchetti Marco , Serretti Alessandro , Sarchiapone Marco
Published: March 2012

Introduction

Self-harm is a direct, socially unacceptable,repetitive behavior that causes minor to moderate physical injury without suicidal intent. It is also a significant and growing concern among prison inmates, although it has been rarely studied. In the present study, we aimed to investigate demographic, psychosocial, and clinical variables associated to this critical bahaviour in a high risk sample of 1,555 male prisoners.

Methods

Prisoners were interviewed about their history of self-mutilation, psychiatric history,and forensic history. The prisoners completed the Barratt Impulsivity Scale, Buss-Durkee Hostility Inventory, Eysenck Personality Questionnaire, and Childhood Trauma Questionnaire.

Results

Eighteen percent of prisoners had a history of self-harm. They more frequently reported childhood traumas, were more likely to be unmarried, previously imprisoned, tested positive for substance abuse, had a history of suicide attempt, and more likely showed violent tendencies.

Discussion

Self-harm among prisoners is common, being found in almost 20% of the subjects in our sample. Self-mutilation among prisoners appears to be multi-factorial with developmental, socio-demographic, psychiatric, and personality determinants.

Conclusion

Self-harm is associated with critical behaviors such as violence, substance abuse and suicide attempts, which represent major critical problems in contention environments.
A CLOSED-FORM SOLUTION TO A MODEL OF TWO-SIDED, PARTIAL ALTRUISM
Authors: Fernandes Ana
Published: March 2012

This paper presents a closed-form characterization of the allocation of resources in an overlapping generations model of two-sided, partial altruism. Three assumptions are made: (i) parents and children play Markov strategies, (ii) utility takes the CRRA form, and (iii) the income of children is stochastic but proportional to the saving of parents. In families where children are rich relative to their parents, saving rates—measured as a function of the family's total resources—are higher than when children are poor relative to their parents. Income redistribution from the old to the young, therefore, leads to an increase in aggregate saving.
An ancient shallow slip event on the Mentawai segment of the Sunda megathrust, Sumatra
Authors: Philibosian Belle , Sieh Kerry , Natawidjaja Danny H. , Chiang Hong‐Wei , Shen Chuan‐Chou , Suwargadi Bambang W. , Hill Emma M. , Edwards R. Lawrence
Published: March 2012

The outer‐arc islands of western Sumatra rise during great megathrust earthquakes, due to large slip on the underlying megathrust. In contrast, the islands subsided up to a few centimeters during the recent tsunamigenic earthquake of October 2010, due to slip far updip, near the trench. Coral microatolls on one of the islands recorded a much larger subsidence, at least 35 cm, during an event in approximately A.D. 1314. We calculate a suite of slip models, slightly deeper and/or larger than the 2010 event, that are consistent with this large amount of subsidence. Sea level records from older coral microatolls suggest that these events occur at least once every millennium, but likely far less frequently than their great downdip neighbors. The revelation that shallow slip events are important contributors to the seismic cycle of the Mentawai segment further complicates our understanding of this subduction megathrust and our assessment of the region's exposure to seismic and tsunami hazards.
River channel slope, flow resistance, and gravel entrainment thresholds
Authors: Ferguson Robert I.
Published: March 2012

River beds are traditionally assumed to become mobile at a fixed value of nondimensional shear stress, but several flume and field studies have found that the critical value is higher in steep shallow flows. Explanations for this have been proposed in terms of the force balance on individual grains. The trend can also be understood in bulk‐flow terms if total flow resistance has “base” and “additional” components, the latter due to protruding immobile grains as well as any bedforms, and the stress corresponding to “additional” resistance is not available for grain movement in threshold conditions. A quantitative model based on these assumptions predicts that critical Shields stress increases with slope, critical stream power is near‐invariant with slope, and each has a secondary dependence on bed sorting. The proposed slope dependence is similar to what force‐balance models predict and consistent with flume data and most field data. Possible explanations are considered for the inability of this and other models to match the very low critical values of width‐averaged stress and power reported for some low‐gradient gravel bed rivers.
Stability of infinite slopes under transient partially saturated seepage conditions
Authors: Godt Jonathan W. , Şener‐Kaya Başak , Lu Ning , Baum Rex L.
Published: March 2012

Prediction of the location and timing of rainfall‐induced shallow landslides is desired by organizations responsible for hazard management and warnings. However, hydrologic and mechanical processes in the vadose zone complicate such predictions. Infiltrating rainfall must typically pass through an unsaturated layer before reaching the irregular and usually discontinuous shallow water table. This process is dynamic and a function of precipitation intensity and duration, the initial moisture conditions and hydrologic properties of the hillside materials, and the geometry, stratigraphy, and vegetation of the hillslope. As a result, pore water pressures, volumetric water content, effective stress, and thus the propensity for landsliding vary over seasonal and shorter time scales. We apply a general framework for assessing the stability of infinite slopes under transient variably saturated conditions. The framework includes profiles of pressure head and volumetric water content combined with a general effective stress for slope stability analysis. The general effective stress, or suction stress, provides a means for rigorous quantification of stress changes due to rainfall and infiltration and thus the analysis of slope stability over the range of volumetric water contents and pressure heads relevant to shallow landslide initiation. We present results using an analytical solution for transient infiltration for a range of soil texture and hydrological properties typical of landslide‐prone hillslopes and show the effect of these properties on the timing and depth of slope failure. We follow by analyzing field‐monitoring data acquired prior to shallow landslide failure of a hillside near Seattle, Washington, and show that the timing of the slide was predictable using measured pressure head and volumetric water content and show how the approach can be used in a forward manner using a numerical model for transient infiltration.
Subduction beneath Gibraltar? Recent studies provide answers
Authors: Gutscher Marc‐André
Published: March 2012

On 1 November 1755 a powerful earthquake shook Portugal, Spain, and northern Morocco, with tremors felt across most of northwestern Europe and as far west as the Azores and as far south as the Cape Verde islands [Gutscher, 2004]. Known as the Great Lisbon Earthquake, the event was followed by a devastating tsunami that swept the nearby Atlantic coast with waves 5–15 meters high; tsunami waves 1–5 meters high were also observed in the Antilles [Gutscher et al., 2006]. Following the earthquake, huge conflagrations raged for days in the city of Lisbon, where 85% of buildings were leveled. In total, 40,000–60,000 people are estimated to have perished. Modern estimates now consider that the earthquake's magnitude was between 8.5 and 9.0, making it among the strongest earthquakes ever felt. But questions on the earthquake's exact mechanism continue to perplex researchers. Also perplexing are observations of extreme stretching of crust in the western Alboran Sea, an arm of the Mediterranean between Spain and Morocco. Could the processes that stretched the crust there be related to the forces that triggered the 1755 earthquake?
Characteristics of magnetospheric energetics during geomagnetic storms
Authors: Li H. , Wang C. , Xu W. Y. , Kan J. R.
Published: March 2012

To investigate the magnetospheric energetics during magnetic storms, we performed a statistical survey of 307 geomagnetic storms between 1995 and 2009. For the purpose of getting a detailed understanding of the energy processes, we conducted our study of storm‐time energetics for three time durations: the main phase, the recovery phase, and the total storm period. We found that the partition of the energy dissipation via the ring current injection and high‐latitude ionospheric dissipation is controlled by the storm intensity. The proportion of the ring current injection increases linearly as the storm intensity increases for all three time durations. For moderate storms, the high‐latitude ionospheric dissipation is dominant, with only ∼30% energy dissipated via the ring current; whereas for superstorms, the ring current injection becomes dominant, with ∼70% energy dissipated via the ring current. We also confirmed the essential and crucial role of the total energy input into the magnetosphere during the main phase in controlling the storm intensity. The total energy input during the main phase is directly proportional to the storm intensity. Their correlation efficiency is as high as 0.85. The storm‐time energy budget was also quantified in this study. The coupling efficiency indicates an exponential decay as the storm intensity increases, with the coupling efficiency during the main phase less than that during the recovery phase.
SuperMAG‐based partial ring current indices
Authors: Newell P. T. , Gjerloev J. W.
Published: March 2012

Using the extensive set of stations in the SuperMAG collaboration, we introduce partial ring current indices, which provide new insights into ring current development. The indices are labeled SMR‐00, SMR‐06, SMR‐12 and SMR‐18 for their center local time range. These indices incorporate data from 98 mid and low latitude stations. The behavior of these local time indices during storms and substorms, on both an individual and superposed epoch basis, produces consistent patterns. The initial positive spike before a storm, which results from solar wind pressure enhancements, is seen simultaneously at all local times. Once the main phase of the storm begins, however, SMR‐18 nearly always drops fastest and furthest in magnitude, while SMR‐06 drops more slowly (i.e., has weaker ring current signatures), and never as far. Symmetry is, in fact, not reached until storm recovery is well underway, with a typical symmetry point of about 20–25 h after onset. If the main phase continues to new depths (larger magnitude negative SMR) over a longer time period, the SMR‐18 sector will continue to lead, and SMR‐06 to lag. There has been controversy over the extent to which substorm auroral and cross‐tail currents perturb Dst and SYM‐H signatures. The signature of substorms can be seen very clearly as a positive spike of roughly 10 nT magnitude in SMR‐00, and only to a much lesser extent elsewhere. The SMR global index, and thus also SYM‐H, experiences only a small immediate perturbation from a substorm onset, ending with a net drop of a few nT. Since there are typically only 1–2 substorms in a main phase, substorms are a minor factor in the development of the storm time ring current. Indeed, because even the peak perturbation of substorms currents in the most affected sector (which is midnight) is nearly an order of magnitude smaller than the storm perturbation (about 10 nT versus 80 nT), fluctuations in the cross‐tail and field‐aligned currents in general are not a major influence over SMR. The pattern of LT substorm responses, with a strong positive SMR‐00 effect, weak positive SMR‐06 effect, and negative SMR‐18 effect implies it is field‐aligned currents and not the cross‐tail currents which create modest perturbations in the putatively ring current indices.
AGMAAS: a GIS integrated tool for modelling wind-borne spreading of FMD virus
Authors: Sábitz Judit , Solymosi Zoltán Barcza , Solymosi Norbert
Published: March 2012

The aim of our work was to develop a tool integrated into Quantum GIS (QGIS) that can help the user estimate and visualize the possible infective areas around an outbreak based on HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model.
Loss‐of‐Function Mutations in MC4R Are Very Rare in the Greek Severely Obese Adult Population
Authors: Rouskas Konstantinos , Meyre David , Stutzmann Fanny , Paletas Konstantinos , Papazoglou Dimitrios , Vatin Vincent , Marchand Marion , Kouvatsi Anastasia , Froguel Philippe
Published: March 2012

Melanocortin‐4 receptor (MC4R) loss‐of‐function mutations are the commonest genetic cause of human monogenic obesity, so far. The contribution of MC4R coding mutations to severe obesity in the high‐obesity prone Greek population has not been investigated to date. We determined the MC4R coding sequence of 510 obese and 469 lean control subjects of Greek origin, and we estimated the prevalence and the penetrance on obesity of MC4R loss‐of‐function mutations. The functional impact of novel nonsynonymous variants detected was investigated in vitro. We found two novel synonymous mutations (L23L and I102I), four nonsynonymous mutations (T112M, S127L, N274S, and S295L), and two polymorphisms (V103I and I251L) previously described in literature. We also detected a novel mutation (L207V) in a severely obese 69‐year‐old female patient, although the mutation did not cosegregate with obesity in the corresponding pedigree and had no functional consequences on MC4R protein function. Loss‐of‐function mutations represented 75% of all nonsynonymous rare mutations identified among lean carriers and only 25% among obese subjects (P = 0.0001). The prevalence of loss‐of‐function mutations was lower in the obese group than in lean control subjects (0.20 vs. 0.64%) but this difference was not significant. Therefore, the estimated penetrance of deleterious MC4R mutations was very low (6.3%) in heterozygous Greek carriers of MC4R loss‐of‐function mutations. Our data suggest that MC4R loss‐of‐function mutations are rare in the Greek population. MC4R genetic deficiency is unlikely to explain the high propensity to develop severe obesity in this specific population.
Adenosine A2a receptor stimulation prevents hepatocyte lipotoxicity and non-alcoholic steatohepatitis (NASH) in rats
Authors: Imarisio Chiara , Alchera Elisa , Sutti Salvatore , Valente Guido , Boccafoschi Francesca , Albano Emanuele , Carini Rita
Published: March 2012

NEFA (non-esterified ‘free’ fatty acid)-mediated lipotoxicity plays a critical role in the pathogenesis of NASH (non-alcoholic steatohepatitis). In the light of the growing need for new therapeutic options for NASH, we investigated the action of A2aR (adenosine A2a receptor) stimulation against lipotoxicity. The effects of the A2aR agonist CGS21680 [2-p-(2-carboxyethyl)phenethylamino-5′-N-ethylcarboxyamidoadenosine] were evaluated ‘in vitro’ in liver cells exposed to SA (stearic acid) and ‘in vivo’ in rats with NASH induced by 8 weeks of feeding with an MCD diet (methionine/choline-deficient diet). In cultured hepatocytes, SA promoted apoptosis by inducing MKK4 (mitogen-activated protein kinase kinase 4)/SEK1 (stress-activated protein kinase/extracellular-signal-regulated kinase kinase-1) and JNK-1/2 (c-Jun N-terminal kinase-1/2) activation. CGS21680 addition prevented JNK-1/2 activation and reduced apoptosis without interfering with lipid accumulation. CGS21680 action required PI3K (phosphoinositide 3-kinase)/Akt-mediated block of MKK4/SEK1. Consistently, PI3K inhibition with wortmannin abolished the cytoprotective action of CGS21680 and reverted MKK4 inhibition. SA lipotoxicity was also prevented by transfecting HTC cells with a specific MKK4/SEK1 siRNA (small interfering RNA). In rats receiving the MCD diet, the development of NASH was associated with MKK4/SEK1 and JNK-1/2 activation. CGS21680 (0.5 mg/kg of body weight, intraperitoneal) administration to MCD-fed rats prevented JNK-1/2 activation by acting on MKK4/SEK1. CGS21680 also effectively reduced NASH-associated ALT (alanine aminotransferase) release, hepatocyte apoptosis, liver inflammation and fibrosis without affecting hepatic steatosis. Taken together, these results demonstrate that, by inhibiting JNK-1/2, A2aR stimulation reduces lipotoxicity and ameliorates NASH, giving a rationale to investigate A2aR agonists as possible new therapeutic agents in preventing fatty liver progression to NASH.
Two-fluid simulations of shock wave propagation and shock-bubble interaction in collisionless plasma
Authors: Mori Koichi
Published: March 2012

The propagation of collisionless shock waves and the influence of the space-charge field on the development of fluid instabilities induced by a collisionless shock wave are investigated by solving the two-fluid plasma equations numerically in two space-dimensions. A second-order accurate Riemann solver is employed to sharply capture the shock wave and contact discontinuity. First, a series of shock-tube problems is solved to verify the method. The shock structure similar to that obtained in a previous particle-in-cell (PIC) simulation is reproduced. However, it is found that the shock wave propagates at speeds higher than the PIC results for high initial density ratios at the shock tube diaphragm. Second, the interactions between a collisionless shock wave of Mach number 1.6 and an isolated cylindrical bubble of Atwood number 0.81 are investigated. It is found that in addition to the well-known Richtmyer-Meshkov instability, filamentary fluid-instability is induced at the bubble interface introducing turbulence in the region ahead of the shock wave.
Direct and indirect two-photon absorption in Ge within the effective mass approximation
Authors: Garcia Hernando , Avanaki Kobra Nasiri
Published: March 2012

We have calculated the two photon absorption coefficient for Ge within the effective mass approximation for the direct as well as the indirect gap region. By including all the possible contributions to the nonlinear absorption based on the Ge band structure, we found excellent agreement with the recent experimental report on the two photon absorption in Ge. It is found that even though the direct transition is stronger than the indirect process, a tail at the low end of the energy spectrum appears, and the ultimate limit for the two photon absorption is half of the indirect gap energy.
The origin of the conductivity maximum in molten salts. I. Bismuth chloride
Authors: Clay Adam T. , Kuntz Colin M. , Johnson Keith E. , East Allan L. L.
Published: March 2012

A new theory is presented to explain the conductivity maxima of molten salts (versus temperature and pressure). In the new theory, conductivity is due to ions hopping from counterion to counterion, and its temperature dependence can be explained with an ordinary Arrhenius equation in which the frequency prefactor A (for hopping opportunities) and activation energy Ea (for hopping) are density dependent. The conductivity maximum is due to competing effects: as density decreases, the frequency of opportunities for hopping increases, but the probability that an opportunity is successfully hopped decreases due to rising Ea caused by the increased hopping distance. The theory is successfully applied to molten bismuth (III) chloride, and supported by density-functional based molecular dynamics simulations which not only reproduce the conductivity maximum, but disprove the long-standing conjecture that this liquid features an equilibrium between BiCl3 molecules, and BiCl2+ and BiCl4− ions that shifts to the left with increasing temperature.
Study of nonlinear dynamics in magnetron by using circuitry model
Authors: Li Daohui , Chen Xiaodong
Published: March 2012

A circuitry model is established to study the nonlinear dynamics of magnetron through solving a third order differential equation. The steady, oscillatory oscillation and even chaotic state have been observed when changing different control parameters, i.e., the anode current and the load. The observation of the anode current increase causing the magnetron to operate in chaos agrees well to that in the experiments conducted by other researchers.
A novel stress design for the type-II hetero-junction solar cell with superior performance
Authors: Liao M.-H. , Chen C.-H. , Chang L.-C. , Yang C.
Published: March 2012

High efficient surface textured SiGe-based solar cell is proposed by the designed top nano-level surface trench structure and the optimized SiGe/Si type-II substrate hetero-junction design. The surface reflectance rate of solar cell can be successfully reduced about 3 times (totally from 32% to ∼10%) by the nano-surface textured structure with obvious photonic crystal effect, simulated by finite differential time domain simulation. With different top surface trench spacing (d) structure design on the nanometer level, broadband antireflection and total absorption rate can be realized and enhanced greatly, respectively. Moreover, SiGe/Si hetero-structure substrate is also implemented to enhance an additional solar cell efficiency about 3% in this work, not only due to the originally higher absorption rate in SiGe-based material but also due to optimized SiGe/Si type-II hetero-structure substrate design. The offset and discontinuousness of the energy band between n+-Si and grown fully strained Si0.9Ge0.1 type-II hetero-junction structure can prevent hole diffusion into the n+-Si layer and have the larger Voc. With the integration of these two key technologies including nano-level surface trench structure design and SiGe/Si type-II hetero-structure optimization, the high efficient (∼18% for the stable production and 21% for the peak record) nano-surface textured SiGe-based solar cell can be achieved and demonstrated in this work.
Axisymmetric intrusions in two-layer and uniformly stratified environments with and without rotation
Authors: Holdsworth Amber M. , Barrett Kai J. , Sutherland Bruce R.
Published: March 2012

Lock-release laboratory experiments have been performed to examine the collapse of a localized cylindrical mixed patch of fluid in both two-layer and uniformly stratified ambients. The experiments were performed with and without rotation. Unlike bottom propagating gravity currents, non-rotating intrusions typically propagated many lock radii at constant speed, sometimes stopping abruptly due to interactions with internal waves generated by the return flow into the lock. The initial front speeds of the resulting approximately axisymmetric intrusions emanating from locks of comparable depth and radius were found to be 30%–35% less than the predictions of rectilinear theory. Rotation had no impact on the intrusion's initial speed. However, it limited the maximum distance propagated by the intrusion and caused the patch to expand and contract as it approached geostrophic balance.
Shear wave induced resonance elastography of spherical masses with polarized torsional waves
Authors: Hadj Henni Anis , Schmitt Cédric , Trop Isabelle , Cloutier Guy
Published: March 2012

Shear wave induced resonance (SWIR) is a technique for dynamic ultrasound elastography of confined mechanical inclusions. It was developed for breast tumor imaging and tissue characterization. This method relies on the polarization of torsional shear waves modeled with the Helmholtz equation in spherical coordinates. To validate modeling, an invitro set-up was used to measure and image the first three eigenfrequencies and eigenmodes of a soft sphere. A preliminary invivo SWIR measurement on a breast fibroadenoma is also reported. Results revealed the potential of SWIR elastography to detect and mechanically characterize breast lesions for early cancer detection.
Electromagnetically induced transparency in terahertz plasmonic metamaterials via dual excitation pathways of the dark mode
Authors: Liu Xiaojun , Gu Jianqiang , Singh Ranjan , Ma Yingfang , Zhu Jun , Tian Zhen , He Mingxia , Han Jiaguang , Zhang Weili
Published: March 2012

We observe the excitation and tuning of electromagnetically induced transparency (EIT) by the interference between different excitation pathways of the dark mode in a planar terahertz metamaterial. The EIT unit cell consists of a cut wire as the bright resonator and a pair of split ring resonators (SRRs) as the dark element. The dark mode resonance is excited by both the electric and magnetic fields when the SRR pair translates along the wire without altering the lateral distance between the resonators. The electric and magnetic pathways of exciting the dark mode allows for a giant amplitude modulation of the EIT resonance.
Slow light for deep tissue imaging with ultrasound modulation
Authors: Zhang Huiliang , Sabooni Mahmood , Rippe Lars , Kim Chulhong , Kröll Stefan , Wang Lihong V. , Hemmer Philip R.
Published: March 2012

Slow light has been extensively studied for applications ranging from optical delay lines to single photon quantum storage. Here, we show that the time delay of slow-light significantly improves the performance of the narrowband spectral filters needed to optically detect ultrasound from deep inside highly scattering tissue. We demonstrate this capability with a 9 cm thick tissue phantom, having 10 cm−1 reduced scattering coefficient, and achieve an unprecedented background-free signal. Based on the data, we project real time imaging at video rates in even thicker phantoms and possibly deep enough into real tissue for clinical applications like early cancer detection.
Observation of copious emission at the fundamental frequency by a Smith-Purcell free-electron laser with sidewalls
Authors: Gardelle J. , Modin P. , Donohue J. T.
Published: March 2012

An experiment at microwave frequencies confirms the recent prediction that a Smith-Purcell [S. J. Smith and E. M. Purcell, Phys. Rev. 92, 1069 (1953)] free-electron laser equipped with sidewalls can emit radiation at the frequency of the surface wave. The power output is considerably greater than for the previously observed emission at the second harmonic, in agreement with three-dimensional simulations. The dependence of frequency on beam energy and emission angle is in good agreement with three-dimensional theory and simulations. Provided that a reduction in scale can be achieved, a path is open to coherent Smith-Purcell radiation at terahertz frequency.
A weakly coupled semiconductor superlattice as a potential for a radio frequency modulated terahertz light emitter
Authors: Rasulova G. K. , Brunkov P. N. , Pentin I. V. , Egorov A. Yu. , Knyazev D. A. , Andrianov A. V. , Zakhar’in A. O. , Konnikov S. G. , Gol’tsman G. N.
Published: March 2012

The bolometer response to THz radiation from a weakly coupled GaAs/AlGaAs superlattice biased in the self-oscillations regime has been observed. The bolometer signal is modulated with the frequency equal to the fundamental frequency of superlattice self-oscillations. The frequency spectrum of the bolometer signal contains higher harmonics whose frequency is a multiple of fundamental frequency of self-oscillations.
Molecular dynamics of n-hexane: A quasi-elastic neutron scattering study on the bulk and spatially nanochannel-confined liquid
Authors: Hofmann Tommy , Wallacher Dirk , Mayorova Maria , Zorn Reiner , Frick Bernhard , Huber Patrick
Published: March 2012

We present incoherent quasi-elastic neutron scattering measurements in a wave vector transfer range from 0.4 Å−1 to 1.6Å −1 on liquid n-hexane confined in cylindrical, parallel-aligned nanochannels of 6 nm mean diameter and 260 μm length in monolithic, mesoporous silicon. They are complemented with, and compared to, measurements on the bulk system in a temperature range from 50 K to 250 K. The time-of-flight spectra of the bulk liquid (BL) can be modeled by microscopic translational as well as fast localized rotational, thermally excited, stochastic motions of the molecules. In the nano-confined state of the liquid, which was prepared by vapor condensation, we find two molecular populations with distinct dynamics, a fraction which is immobile on the time scale of 1 ps to 100 ps probed in our experiments and a second component with a self-diffusion dynamics slightly slower than observed for the bulk liquid. No hints of an anisotropy of the translational diffusion with regard to the orientation of the channels' long axes have been found. The immobile fraction amounts to about 5% at 250 K, gradually increases upon cooling and exhibits an abrupt increase at 160 K (20 K below bulk crystallization), which indicates pore freezing.
Origin of magnetic properties and martensitic transformation of Ni-Mn-In magnetic shape memory alloys
Authors: Tan C. L. , Huang Y. W. , Tian X. H. , Jiang J. X. , Cai W.
Published: March 2012

The nature of unique magnetic properties and martensitic transformation of Ni2Mn1+xIn1−x shape memory alloy has been revealed by first-principles calculations. The uncommon magnetic properties occurring upon martensitic transformation are originated from the change of Mn-Mn interatomic distances. The critical value of Mn-Mn interatomic distance corresponding to the change of magnetic interactions has been determined. A decrease of the intensity of Ni 3d states at the Fermi level upon martensitic transformation has been observed for x = 0.5. Moreover, the Ni 3d-Mn 3d hybridization plays an important role in establishing the magnetic properties and driving the martensitic transformation.
Non-Onsager mechanism of long-wave photogeneration in amorphous selenium at high electric fields
Authors: Reznik A. , Jandieri K. , Gebhard F. , Baranovskii S. D.
Published: March 2012

The quantum efficiency of the free-carrier-photogeneration in amorphous selenium avalanche blocking structures is studied experimentally in a wide range of wavelengths (380–600 nm) at high electric fields (10−112.5Vμm−1). While at comparatively small excitation wavelengths (up to ≃540nm), our experimental results are consistent with the Onsager theory of electron-hole pair dissociation [L. Onsager, Phys. Rev. 54, 554 (1938)], at larger wavelengths (540–600 nm) and high electric fields Onsager theory fails to explain our results. The reason for the failure of the Onsager approach is discussed and an alternative theoretical tool is adopted to account for the experimental observations.