bluuebunny/crossref_metadata_2025 huggingface dataset:
Choice with delayed or uncertain reinforcers in rats: Influence of timeout duration and session length
Authors: Zoratto Francesca , Laviola Giovanni , Adriani Walter
Published: May 2012

Interest is rising for animal modeling of impaired behavioral inhibition. Impulsivity and risk proneness, key symptoms of impulse‐control disorders, are classically measured by Intolerance to Delay (ID) and Probabilistic Delivery (PD) tasks, requiring choice between a “Small & Soon” or “Sure” (SS) versus a “Large & Late” or “Luck‐Linked” (LL or LLL, respectively) reinforcer. Several temporal parameters shall be set, which are not always explicit. Here, we focused on duration of timeout (TO; three groups: 15, 30, or 45 s; Exp. 1) and on session length (SL; three groups: 60, 90, or 120 min; Exp. 2) to determine whether these parameters may affect rats' performance in ID and PD tasks, respectively. In Exp. 1, rats' reaction to increasing experimental delays (absolute values 0–90 s, delay‐equivalent odds 0 to 1.94 ± 0.11) was critically affected by TO duration: a steeper impulsivity curve was found in subjects tested with the longest TO, while random performance was elicited with too short TO. In Exp. 2, a specific “gambling” part was presented (LLL probability lower than 20%). Subjects tested with the shortest session length (60 min), who had a low number of gambling opportunities (performed trials = 84.33 ± 1.91), exhibited a profile of risk proneness, with sustained LLL preference despite high uncertainty and low payoff. Present data demonstrate that TO and SL crucially influence rats' performance in these operant tasks. Their methodological refinement is highly relevant to validate preclinical models for inhibitory‐control impairments. Synapse 66:792–806, 2012. © 2012 Wiley Periodicals, Inc.
Validation of an Ultrasound‐Guided Technique to Establish a Liver‐to‐Coelom Ratio and a Comparative Analysis of the Ratios Among Acclimated and Recently Wild‐Caught Southern Stingrays, Dasyatis Americana
Authors: Grant Krystan R. , Campbell Terry W. , Silver Tawni I. , Olea‐Popelka Francisco J.
Published: May 2012

Southern stingrays, Dasyatis americana, are a well‐represented elasmobranch species in public aquaria and other facilities throughout the world. This study was conducted at a facility that experienced some mortality and replenished the collection with wild‐caught stingrays. A common necropsy finding among the stingrays was a small, dark liver. The objectives of this study were to assess the reliability of an ultrasound‐guided technique for establishing a liver‐to‐coelom ratio by calculating the approximate length of the liver with respect to the coelomic cavity length and then to compare ratios between acclimated captive and wild‐caught stingrays. The ultrasound validation phase of the study measured the distance from the caudal margin of the liver to the pelvic cartilaginous girdle and compared it to the actual distance measured during the necropsy or surgery. There was no significant difference found between the ultrasound and actual distance measurements (P = 0.945). This technique was then used to establish liver‐to‐coelom ratios and compare two groups of stingrays, presumably under different metabolic states at different periods. Liver‐to‐coelom ratios were established during initial examinations as well as 8 months after cohabitation in a touch pool exhibit. There were significant differences in liver‐to‐coelom ratios between the two stingray groups at introduction (median difference = 30.9%, P = 0.007) and after 8 months (median difference = 20.5%, P = 0.008). There were also significant differences in the liver‐to‐coelom ratios within each group at introduction and at 8 months (acclimated group median difference = 20.4%, P = 0.018; wild‐caught group median difference 31%, P = 0.008). Zoo Biol. 32:104‐111, 2013. © 2012 Wiley Periodicals, Inc.
Identification of an amyloid fibril forming peptide comprising residues 46–59 of apolipoprotein A‐I
Authors: Wong Yuan Qi , Binger Katrina J. , Howlett Geoffrey J. , Griffin Michael D.W.
Published: May 2012

apoA‐I
and apoA‐I
bind by X‐ray fiber diffraction (View interaction)
Regulatory mechanism of PAC1 gene expression via Sp1 by nerve growth factor in PC12 cells
Authors: Miura Ayako , Odahara Naoko , Tominaga Aiko , Inoue Kazuhiko , Kambe Yuki , Kurihara Takashi , Miyata Atsuro
Published: May 2012

In addition to VPAC1 and VPAC2, PAC1 is involved in the pleiotropic action of pituitary adenylate cyclase activating polypeptide (PACAP) in the CNS. A luciferase reporter assay for the human PAC1 gene (−2160/+268) revealed that NGF treatment significantly augments the promoter activity of the PAC1 gene. Moreover, the Sp1 site at −282/−273 was shown to be essential for the NGF‐augmented promoter activity of the PAC1 gene. Treatment with U0126, an MEK inhibitor, or Mithramycin A, an Sp1 inhibitor, significantly attenuated promoter activity. These results indicate that activation of Sp1 by the Ras/MAPK pathway might participate in neuron specific expression of the PAC1 gene.
Crosstalk between TGF‐β and hedgehog signaling in cancer
Authors: Javelaud Delphine , Pierrat Marie-Jeanne , Mauviel Alain
Published: May 2012

Hedgehog (HH) and TGF‐β signals control various aspects of embryonic development and cancer progression. While their canonical signal transduction cascades have been well characterized, there is increasing evidence that these pathways are able to exert overlapping activities that challenge efficient therapeutic targeting. We herein review the current knowledge on HH signaling and summarize the recent findings on the crosstalks between the HH and TGF‐β pathways in cancer.
Sex Offender Risk Assessments in the Child Protection Context. Helpful or Not?
Authors: Broadley Karen
Published: May 2012

When a convicted or alleged child sex offender is living, or having contact, with his own children or stepchildren, the obvious worry is that these children are victims or will become victims of sexual abuse. One way of determining the risk of this occurring is for the convicted or alleged offender to undergo a forensic sex offender risk assessment. In this article I raise questions regarding the usefulness of sex offender risk assessments within the statutory child protection context. Most importantly, I ask whether static and dynamic risk assessment instruments can accurately predict the risk an alleged or convicted sex offender poses to his own children. I conclude that ‘high’, ‘moderate’, and ‘low’ risk outcomes of forensic sex offender risk assessments in the child protection context are unreliable and can result in error, and explain that these errors have consequences that, within the child protection context, have consequences that can be dangerous to children.
Strongmen and Straw Men: Authoritarian Regimes and the Initiation of International Conflict
Authors: WEEKS JESSICA L.
Published: May 2012

How do domestic institutions affect autocratic leaders’ decisions to initiate military conflicts? Contrary to the conventional wisdom, I argue that institutions in some kinds of dictatorships allow regime insiders to hold leaders accountable for their foreign policy decisions. However, the preferences and perceptions of these autocratic domestic audiences vary, with domestic audiences in civilian regimes being more skeptical of using military force than the military officers who form the core constituency in military juntas. In personalist regimes in which there is no effective domestic audience, no predictable mechanism exists for restraining or removing overly belligerent leaders, and leaders tend to be selected for personal characteristics that make them more likely to use military force. I combine these arguments to generate a series of hypotheses about the conflict behavior of autocracies and test the hypotheses using new measures of authoritarian regime type. The findings indicate that, despite the conventional focus on differences between democracies and nondemocracies, substantial variation in conflict initiation occurs among authoritarian regimes. Moreover, civilian regimes with powerful elite audiences are no more belligerent overall than democracies. The result is a deeper understanding of the conflict behavior of autocracies, with important implications for scholars as well as policy makers.
EVERY TOPOLOGICALLY AMENABLE LOCALLY COMPACT QUANTUM GROUP IS AMENABLE
Authors: ZOBEIDI AMIN
Published: May 2012

We prove that every topologically amenable locally compact quantum group is amenable. This answers an open problem by Bédos and Tuset [‘Amenability and co-amenability for locally compact quantum groups’, Internat. J. Math.14 (2003), 865–884].
Genetic and environmental predictors of serum 25-hydroxyvitamin D concentrations among middle-aged and elderly Chinese in Singapore
Authors: Robien Kim , Butler Lesley M. , Wang Renwei , Beckman Kenneth B. , Walek Dinesha , Koh Woon-Puay , Yuan Jian-Min
Published: May 2012

Vitamin D is known for maintaining Ca homeostasis and bone structure, and may also decrease susceptibility to chronic and infectious diseases. However, data on vitamin D status and its predictors among Southeast Asian populations are limited. We evaluated the distribution and determinants (genetic and environmental) of serum 25-hydroxyvitamin D (25(OH)D) concentrations among 504 middle-aged and elderly participants (aged 45–74 years) in the Singapore Chinese Health Study. Data on dietary and other lifestyle factors were collected by trained interviewers. Serum 25(OH)D concentrations and genetic polymorphisms in vitamin D metabolism pathway enzymes (cytochrome P450 (CYP)2R1,3A4,27B1,24A1; vitamin D binding protein (also known as group-specific component,GC); and vitamin D receptor) were measured using stored biospecimens. Mean 25(OH)D concentration was 68·8 nmol/l. Serum 25(OH)D concentrations were positively associated with dietary vitamin D intake, and inversely associated with hours spent sitting at work. BMI was not associated with 25(OH)D concentrations.CYP2R1rs10741657, rs12794714, rs1993116;CYP3A4rs2242480; andGCrs4588, rs7041, rs16847015, rs2298849 were statistically significantly associated with 25(OH)D concentrations. Individuals with theGc2-2haplotype (rs4588AA/rs7041TT) had statistically significantly lower 25(OH)D concentrations compared to all otherGchaplotypes (P-trend < 0·001). The majority of participants (86 %) had 25(OH)D concentrations ≥ 50 nmol/l, which is consistent with the 2011 Institute of Medicine (US) recommendation for bone health, and 32 % had concentrations of ≥ 75 nmol/l that are thought to be required for broader health effects. Dietary vitamin D intake, hours spent indoors at work and genetic variation inCYP2R1,CYP3A4andGCare significant predictors of 25(OH)D concentrations among Singapore Chinese.
Multiple symmetrical lipomatosis: case report and literature review
Authors: Sia K J , Tang I P , Tan T Y
Published: May 2012

Objective:

To discuss the pathophysiology and various treatment methods of multiple symmetrical lipomatosis.

Case report:

We report a case of multiple symmetrical lipomatosis in a middle-aged man. He presented to us with an extensive, disfiguring neck mass. Clinical examination and computed tomography suggested a lipomatous mass without compression of vital neck structures. The proximity of the lipomatous mass to the carotid sheaths attracted our interest. We performed surgical excision in this case, because of the deep infiltrative behaviour of the lipoma. The benefits and drawbacks of liposuction and surgical excision of extensive neck lipomatosis are discussed.

Conclusion:

Surgical excision and liposuction are complementary treatments in the management of multiple symmetrical lipomatosis. Patients should be aware of the limitations of both surgical options, and the risk of lipoma recurrence, before surgery. The decision on the mode of surgery relies upon the disease extent, the patient's expectations and the surgeon's experience.
Acute presentation of a plunging ranula causing respiratory distress: case report
Authors: Effat K G
Published: May 2012

Objective:

A plunging ranula is an uncommon cause of neck swelling which typically presents in a gradually progressive fashion. This report describes a rare case of acute presentation of a plunging ranula. The condition progressed rapidly to respiratory distress, requiring urgent surgery.

Case report:

A 14-year-old male student presented with a rapidly enlarging neck swelling associated with a sublingual swelling. Computed tomography suggested the diagnosis of plunging ranula. Several hours after admission, the neck swelling became very tense and the sublingual swelling enlarged dramatically. The tongue was pushed upwards and backwards by the sublingual swelling, causing respiratory embarrassment and requiring urgent surgery. Four months after surgery, there was no evidence of recurrence.

Conclusion:

To the best of the author's knowledge, this is the first case report of a plunging ranula progressing acutely and rapidly to cause respiratory compromise. The literature is reviewed and pertinent features concerning the diagnosis and management of plunging ranula are presented.
Brain functional abnormality in schizo-affective disorder: an fMRI study
Authors: Madre M. , Pomarol-Clotet E. , McKenna P. , Radua J. , Ortiz-Gil J. , Panicali F. , Goikolea J. M. , Vieta E. , Sarró S. , Salvador R. , Amann B. L.
Published: May 2012

Background

Schizo-affective disorder has not been studied to any significant extent using functional imaging. The aim of this study was to examine patterns of brain activation and deactivation in patients meeting strict diagnostic criteria for the disorder.

Method

Thirty-two patients meeting Research Diagnostic Criteria (RDC) for schizo-affective disorder (16 schizomanic and 16 schizodepressive) and 32 matched healthy controls underwent functional magnetic resonance imaging (fMRI) during performance of the n-back task. Linear models were used to obtain maps of activations and deactivations in the groups.

Results

Controls showed activation in a network of frontal and other areas and also deactivation in the medial frontal cortex, the precuneus and the parietal cortex. Schizo-affective patients activated significantly less in prefrontal, parietal and temporal regions than the controls, and also showed failure of deactivation in the medial frontal cortex. When task performance was controlled for, the reduced activation in the dorsolateral prefrontal cortex (DLPFC) and the failure of deactivation of the medial frontal cortex remained significant.

Conclusions

Schizo-affective disorder shows a similar pattern of reduced frontal activation to schizophrenia. The disorder is also characterized by failure of deactivation suggestive of default mode network dysfunction.
Hesiodic reminiscences in Zoroastrian–Hellenistic apocalypses
Authors: Dobroruka Vicente
Published: May 2012

This article fits into the general picture of investigations on meta-historical thinking in Antiquity, as well as possible links between Persian apocalyptic literature and early Christian literature. The paper also explores the long-standing debate on the influence of Zoroastrian thought on Jewish–Christian apocalyptic – or whether it was rather the other way round.
“By virtue of your knowledge”: Scientific materialism and thefatwās of Rashīd Riḍā
Authors: Stolz Daniel A.
Published: May 2012

This article examines severalfatwās by the important Muslim reformer Muḥammad Rashīd Riḍā. It treats thesefatwās as part of a broader Arabic debate on “materialism” at the end of the nineteenth and the beginning of the twentieth century. In this context, Riḍā'sfatwās on materialism illustrate the changing nature of Islamic religious authority in this period, as new kinds of knowledge became available to new kinds of readers.
The Politics of Belonging: Citizenship, Community, and Territory on the Saxon-Bohemian Frontier, 1918–1924
Authors: Murdock Caitlin E.
Published: May 2012

In February 1919, Theresia Prokop submitted an application for German citizenship to the Bautzen administrative district in Saxony. The application showed that Prokop was originally from northern Bohemia, had lived in Saxony since 1901, and was a “Bohemian” citizen of “German-Austrian” nationality. Further, it noted: “It is her dearest wish to become German.”
Staging the Nation in Fascist Italy's “New Provinces”
Authors: Pergher Roberta
Published: May 2012

Read any textbook account of interwar Europe, and “indifference to nation” is not likely to figure as a heading. On the contrary, the talk will be of untrammeled nationalist rivalries leading the continent to ruin. In the territories of Eastern and South Eastern Europe that had once been part of the polyglot Habsburg and Ottoman empires, we will be reminded, nationalist hatred and border conflicts paved the way to World War I. And in the aftermath of that war, the regimes of Mussolini and Hitler took glorification of the national community to new heights, unleashing colonial and continental wars of conquest and annihilation. Small wonder that when many Europeans looked back from the rubble of 1945, what they saw was far too much commitment to nation, not too little. Indeed, the aspiration of many idealists in 1945 was precisely to supersede the nationalist rivalries and affiliations that they saw as so detrimental to peaceful coexistence and to create some kind of supranational European loyalty and structure instead.
Performing Ancient Drama in Mask: the Case of Greek Tragedy
Authors: Vervain Chris
Published: May 2012

Chris Vervain is a mask maker who has for a number of years directed masked Greek drama. On the basis of the research she has undertaken using her own masks, in this article she considers some of the practical issues involved in a masked staging of the plays today, drawing specifically on her experience of directing the Bacchae and the Antigone. Here she extends the discussion started previously in ‘Performing Ancient Drama in Mask: the Case of Greek New Comedy’ in NTQ 79 (August 2004). Earlier, with David Wiles, she contributed ‘The Masks of Greek Tragedy as Point of Departure for Modern Performance’ to NTQ 67 (August 2001). In 2008 she completed a doctorate on masks in Greek tragedy at Royal Holloway, University of London.
‘Argue with Us!’: Audience Co-creation through Post-Performance Discussions
Authors: Heim Caroline
Published: May 2012

In this article Caroline Heim explores an avenue for the audience's contribution to the theatrical event that has emerged as increasingly important over the past decade: postperformance discussions. With the exception of theatres that actively encourage argument such as the Staatstheater Stuttgart, most extant audience discussions in Western mainstream theatres privilege the voice of the theatre expert. Caroline Heim presents case studies of post-performance discussions held after performances of Anne of the Thousand Days and Who's Afraid of Virginia Woolf? which trialled a new model of audience co-creation. An audience text which informs the theatrical event was created, and a new role, that of audience critic, established in the process. Caroline Heim is a lecturer in Performance Studies at Queensland University of Technology. Her PhD examined the changing role of theatre audiences in recent years.
The use of the Internet in collecting CDI data – an example from Norway
Authors: KRISTOFFERSEN KRISTIAN E. , SIMONSEN HANNE GRAM , BLESES DORTHE , WEHBERG SONJA , JØRGENSEN RUNE NØRGÅRD , EIESLAND ELI ANNE , HENRIKSEN LAILA YVONNE
Published: May 2012

This article presents the methodology used in a population-based study of early communicative development in Norwegian children using an adaptation of the MacArthur-Bates communicative development inventories (CDI), comprising approximately 6500 children aged between 0 ; 8 and 3 ; 0. To our knowledge, this is the first CDI study collecting data via the Internet. After a short description of the procedures used in adapting the CDI to Norwegian and the selection of participants, we discuss the advantages and potential pitfalls of using web-based forms as a method of data collection. We found that use of web-based forms was far less time-consuming, and therefore also far less expensive than the traditional paper-based forms. The risk of coding errors was virtually eliminated with this method. We conclude that in a society with high access to the Internet, this is a method well worth pursuing.
Adult congenital heart disease interventions: recommendations from a Joint Working Group of the British Congenital Cardiac Association, British Cardiovascular Intervention Society, and the British Cardiovascular Society
Authors: Qureshi Shakeel A. , Hildick-Smith David , de Giovanni Jo , Clift Paul , Stuart Graham , Henderson Rob , Brecker Stephen , Hackett David , Ray Simon , de Belder Mark
Published: May 2012

In order to optimise care of the adult patients with complex congenital heart disease, there is a need to develop recommendations for interventions. This document is the work of representatives of the three relevant societies and provides recommendations for institutions and operators performing cardiac interventions in these patients.
Legitimacy from above: the partisan foundations of support for the political system in democracies
Authors: Anderson Christopher J. , Just Aida
Published: May 2012

We investigate the partisan foundations of political legitimacy. We argue that the goals parties pursue shape their supporters’ views about the political system via the messages they communicate about the desirability of the political system. Combining public opinion survey data collected in 15 democracies with data on the goal orientations and policy positions of 116 political parties, we find that office-seeking parties take more positive positions toward the status quo of the political regime than policy-seeking parties. Moreover, we find that these positions have consequences. Specifically, supporters of parties with more positive positions toward the system report systematically higher levels of support than supporters of parties that communicate more negative views. Taken together, these findings suggest that political parties play an active role in shaping citizens’ views of the political system and that office-seeking parties in particular mobilize consent among citizens in contemporary democracies.
Early cohort mortality predicts the rate of aging in the cohort: a historical analysis
Authors: Beltrán-Sánchez H. , Crimmins E. M. , Finch C. E.
Published: May 2012

Early environmental influences on later-life health and mortality are well recognized in the doubling of life expectancy since 1800. To further define these relationships, we analyzed the associations between early-life mortality and both the estimated mortality level at age 40 and the exponential acceleration in mortality rates with age characterized by the Gompertz model. Using mortality data from 630 cohorts born throughout the 19th and early 20th century in nine European countries, we developed a multilevel model that accounts for cohort and period effects in later-life mortality. We show that early-life mortality, which is linked to exposure to infection and poor nutrition, predicts both the estimated cohort mortality level at age 40 and the subsequent Gompertz rate of mortality acceleration during aging. After controlling for effects of country and period, the model accounts for the majority of variance in the Gompertz parameters (about 90% of variation in the estimated level of mortality at age 40 and about 78% of variation in the Gompertz slope). The gains in cohort survival to older ages are entirely due to large declines in adult mortality level, because the rates of mortality acceleration at older ages became faster. These findings apply to cohorts born in both the 19th century and the early 20th century. This analysis defines new links in the developmental origins of adult health and disease in which effects of early-life circumstances, such as exposure to infections or poor nutrition, persist into mid-adulthood and remain evident in the cohort mortality rates from ages 40 to 90.
Small ponds with major impact: The relevance of ponds and lakes in permafrost landscapes to carbon dioxide emissions
Authors: Abnizova A. , Siemens J. , Langer M. , Boike J.
Published: May 2012

Although ponds make up roughly half of the total area of surface water in permafrost landscapes, their relevance to carbon dioxide emissions on a landscape scale has, to date, remained largely unknown. We have therefore investigated the inflows and outflows of dissolved organic and inorganic carbon from lakes, ponds, and outlets on Samoylov Island, in the Lena Delta of northeastern Siberia in September 2008, together with their carbon dioxide emissions. Outgassing of carbon dioxide (CO2) from these ponds and lakes, which cover 25% of Samoylov Island, was found to account for between 74 and 81% of the calculated net landscape‐scale CO2 emissions of 0.2–1.1 g C m−2 d−1 during September 2008, of which 28–43% was from ponds and 27–46% from lakes. The lateral export of dissolved carbon was negligible compared to the gaseous emissions due to the small volumes of runoff. The concentrations of dissolved inorganic carbon in the ponds were found to triple during freezeback, highlighting their importance for temporary carbon storage between the time of carbon production and its emission as CO2. If ponds are ignored the total summer emissions of CO2‐C from water bodies of the islands within the entire Lena Delta (0.7–1.3 Tg) are underestimated by between 35 and 62%.
Modeling of slow slip events along the deep subduction zone in the Kii Peninsula and Tokai regions, southwest Japan
Authors: Shibazaki Bunichiro , Obara Kazushige , Matsuzawa Takanori , Hirose Hitoshi
Published: May 2012

In the subduction zone of southwest Japan, short‐term slow slip events (SSEs) occur with low frequency tremors (LFTs) at intervals of several months. Recently LFTs have been located with high resolution and their activities have been examined in detail. By setting the generation zones of SSEs such that these zones contain the LFT hypocenters, we simulate SSEs on a 3D plate interface beneath the Kii Peninsula and Tokai regions by using a rate‐ and state‐dependent friction law with a small cut‐off velocity for the evolution effect. Our numerical results show that recurrence intervals of SSEs in the southern and central Kii Peninsula, in the northern Kii Peninsula, and in the Tokai region are 2.5–3.0, 4.8–5.6, and 3.5–4.5 months, respectively, which are consistent with observed SSE activity. Our simulation also produces a multisegment event that propagates from the Kii to Tokai segments at a speed of 10 km/day, which is consistent with observations. The results suggest that generation zones of LFTs coincide with SSE regions and that these two events are different manifestations of the same slip process along the subduction zone. We also perform 3D modeling of faster events accompanied by short‐term SSEs by considering local circular patches with a smaller critical displacement, surrounded by SSE zones with a larger critical displacement. Local circular patches are set at the observed LFT locations. The simulation reproduces fast events that propagate at a speed of 100–200 km/day during a single SSE event.
Observationally based evaluation of NWP reanalyses in modeling cloud properties over the Southern Great Plains
Authors: Wu Wei , Liu Yangang , Betts Alan K.
Published: May 2012

This study evaluates three major Numerical‐Weather‐Prediction reanalyses (ERA‐Interim, NCEP/NCAR Reanalysis I, and NCEP/DOE Reanalysis II) in modeling surface relative shortwave cloud forcing, cloud fraction, and cloud albedo. The observations used for this evaluation are decade‐long surface‐based continuous measurements of the U.S. Atmospheric Radiation Measurement (ARM) program from 03/25/1997 to 12/31/2008 over the Southern Great Plains site. These cloud properties from the reanalyses are evaluated at multiple temporal scales. Like the observations, all the reanalyses show a strong annual cycle, and relatively weak diurnal or inter‐annual variations of the cloud properties. The reanalyses exhibit significant underestimation on the cloud properties, and the model biases in the cloud properties in general reveal a linear link to one another and are somewhat related to cloud fraction magnitude. Further examination shows that the cloud properties are strongly related to 2‐m relative humidity, especially for the observations and ERA‐Interim. However, the relationship between the cloud properties and 2‐m temperature and specific humidity is much weaker. Also, the cloud fraction biases in the two NCEP reanalyses increase (decrease) with the relative humidity (temperature and specific humidity), but the cloud fraction biases in ERA‐Interim show no (opposite) relationship with the relative humidity (temperature and specific humidity). The relative humidity biases have a positive (negative) linear relationship with the specific humidity (temperature) biases. A combined statistical analysis using the technique of Taylor diagrams and a newly developed metric “Relative Euclidean Distance” indicates that ERA‐Interim and NCEP/NCAR reanalyses have the best and worst overall performance in modeling the cloud and meteorological properties examined, respectively, except that NCEP/DOE Reanalysis II ranks the best in modeling the monthly temperature and specific humidity.
The impact of space and time averaging on the spatial correlation of rainfall
Authors: Luini L. , Capsoni C.
Published: May 2012

Nowadays a huge amount of data is available for the statistical characterization of rainfall worldwide, although unfortunately not always with the adequate spatial and temporal resolution required for the very high demanding telecommunication applications. On the basis of the NIMROD radar network composite rain maps, first, this paper investigates separately the impact of space or time integration on the spatial correlation of rainfall ρ, a key parameter for most Propagation Impairment Mitigation Techniques (PIMTs), as well as for many prediction models such as time‐space rain field generators. Analytical formulations are proposed to model the average trend ofρ with the distance d between two sites as a function of the integration time T or the integration area A, which, in turn, can be used to de‐integrate the spatial correlation information estimated respectively from networks of raingauges with long integration time or from radar data with coarse spatial resolution. As an example, the last part of the paper compares the spatial rain decorrelation trends estimated by a database of radar maps collected in Northern Italy with the ones de‐integrated from products of meteorological re‐analyses (ERA40) or Earth Observation missions (TMPA 3B42).
E‐plane radiation pattern analysis of rectangular horn antennas with V‐shaped corrugations by UTD‐PO formulation
Authors: Rodríguez José‐Víctor , Quesada‐Pereira Fernando , Juan‐Llácer Leandro , Verdú‐Rodríguez Elisa , Molina‐García‐Pardo José‐María , Álvarez‐Melcón Alejandro
Published: May 2012

A new method for the calculation of the radiation pattern of corrugated E‐plane rectangular horn antennas based on a hybrid uniform theory of diffraction‐physical optics (UTD‐PO) formulation is presented. The method, which allows for the analysis of horns in which V‐shaped corrugations have been considered, has been validated with numerical data obtained through the application of both an electric field integral equation (EFIE) solved by the method of moments (MoM) and the finite element method (FEM)‐based full‐wave electromagnetic analysis software, HFSS. In this sense, the proposed solution is mathematically less complex and computationally more efficient than existing techniques.
Correlation analysis between ionospheric scintillation levels and receiver tracking performance
Authors: Sreeja V. , Aquino M. , Elmas Z. G. , Forte B.
Published: May 2012

Rapid fluctuations in the amplitude and phase of a transionospheric radio signal caused by small scale plasma density irregularities in the ionosphere are known as scintillation. Scintillation can seriously impair a GNSS (Global Navigation Satellite Systems) receiver tracking performance, thus affecting the required levels of availability, accuracy and integrity, and consequently the reliability of modern day GNSS based applications. This paper presents an analysis of correlation between scintillation levels and tracking performance of a GNSS receiver for GPS L1C/A, L2C and GLONASS L1, L2 signals. The analyses make use of data recorded over Presidente Prudente (22.1°S, 51.4°W, dip latitude ∼12.3°S) in Brazil, a location close to the Equatorial Ionisation Anomaly (EIA) crest in Latin America. The study presents for the first time this type of correlation analysis for GPS L2C and GLONASS L1, L2 signals. The scintillation levels are defined by the amplitude scintillation index, S4 and the receiver tracking performance is evaluated by the phase tracking jitter. Both S4 and the phase tracking jitter are estimated from the post correlation In‐Phase (I) and Quadra‐Phase (Q) components logged by the receiver at a high rate. Results reveal that the dependence of the phase tracking jitter on the scintillation levels can be represented by a quadratic fit for the signals. The results presented in this paper are of importance to GNSS users, especially in view of the forthcoming high phase of solar cycle 24 (predicted for 2013).
The evolution of solid density within a thermal explosion. I. Proton radiography of pre-ignition expansion, material motion, and chemical decomposition
Authors: Smilowitz L. , Henson B. F. , Romero J. J. , Asay B. W. , Saunders A. , Merrill F. E. , Morris C. L. , Kwiatkowski K. , Grim G. , Mariam F. , Schwartz C. L. , Hogan G. , Nedrow P. , Murray M. M. , Thompson T. N. , Espinoza C. , Lewis D. , Bainbridge J. , McNeil W. , Rightley P. , Marr-Lyon M.
Published: May 2012

We report proton transmission images obtained during direct heating of a sample of PBX 9501 (a plastic bonded formulation of the explosive nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)) prior to the ignition of a thermal explosion. We describe the application of proton radiography using the 800 MeV proton accelerator at Los Alamos National Laboratory to obtain transmission images in these thermal explosion experiments. We have obtained images at two spatial magnifications and viewing both the radial and the transverse axes of a solid cylindrical sample encased in aluminum. During heating we observe the slow evolution of proton transmission through the samples, with particular detail during material flow associated with the HMX β-δ phase transition. We also directly observe the loss of solid density to decomposition associated with elevated temperatures in the volume defining the ignition location in these experiments. We measure a diameter associated with this volume of 1–2 mm, in agreement with previous estimations of the diameter using spatially resolved fast thermocouples.
Replica exchange with nonequilibrium switches: Enhancing equilibrium sampling by increasing replica overlap
Authors: Ballard Andrew J. , Jarzynski Christopher
Published: May 2012

We describe a replica exchange strategy where trial swap configurations are generated by nonequilibrium switching simulations. By devoting simulation time to the switching simulations, one can systematically increase an effective overlap between replicas, which leads to an increased exchange acceptance rate and less correlated equilibrium samples. In this paper, we derive our method for a general class of stochastic dynamics, and discuss various strategies for enhancing replica overlap through novel dynamical schemes and prudent choices of switching protocols. We then demonstrate our method on a model system of alanine dipeptide in implicit solvent, characterizing decreases in data correlations and gains in sampling efficiency.
Lattice cluster theory of associating polymers. IV. Phase behavior of telechelic polymer solutions
Authors: Dudowicz Jacek , Freed Karl F. , Douglas Jack F.
Published: May 2012

The newly developed lattice cluster theory (in Paper I) for the thermodynamics of solutions of telechelic polymers is used to examine the phase behavior of these complex fluids when effective polymer-solvent interactions are unfavorable. The telechelics are modeled as linear, fully flexible, polymer chains with mono-functional stickers at the two chain ends, and these chains are assumed to self-assemble upon cooling. Phase separation is generated through the interplay of self-assembly and polymer/solvent interactions that leads to an upper critical solution temperature phase separation. The variations of the boundaries for phase stability and the critical temperature and composition are analyzed in detail as functions of the number M of united atom groups in a telechelic chain and the microscopic nearest neighbor interaction energy εs driving the self-assembly. The coupling between self-assembly and unfavorable polymer/solvent interactions produces a wide variety of nontrivial patterns of phase behavior, including an enhancement of miscibility accompanying the increase of the molar mass of the telechelics under certain circumstances. Special attention is devoted to understanding this unusual trend in miscibility.
Orbital ferromagnetism and the Chandrasekhar mass-limit
Authors: Akbari-Moghanjoughi M.
Published: May 2012

In this paper, we use quantum magnetohydrodynamic as well as magnetohydrostatic (MHS) models for a zero-temperature Fermi-Dirac plasma to show the fundamental role of Landau orbital ferromagnetism (LOFER) on the magnetohydrostatic stability of compact stars. It is revealed that the generalized flux-conserved equation of state of form B=βρ2s/3 only with conditions 0≤s≤1 and 0≤β<2π can lead to a stable compact stellar configuration. The distinct critical value βcr=2π is shown to affect the magnetohydrostatic stability of the LOFER (s = 1) state and the magnetic field strength limit on the compact stellar configuration. Furthermore, the value of the parameter β is remarked to fundamentally alter the Chandrasekhar mass-radius relation and the known mass-limit on white dwarfs when the star is in LOFER state. Current findings can help to understand the role of flux-frozen ferromagnetism and its fundamental role on hydrostatic stability of relativistically degenerate super-dense plasmas such as white dwarfs.
A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths
Authors: Scott R. H. H. , Perez F. , Santos J. J. , Ridgers C. P. , Davies J. R. , Lancaster K. L. , Baton S. D. , Nicolai Ph. , Trines R. M. G. M. , Bell A. R. , Hulin S. , Tzoufras M. , Rose S. J. , Norreys P. A.
Published: May 2012

A systematic experimental and computational investigation of the effects of three well characterized density scalelengths on fast electron energy transport in ultra-intense laser-solid interactions has been performed. Experimental evidence is presented which shows that, when the density scalelength is sufficiently large, the fast electron beam entering the solid-density plasma is best described by two distinct populations: those accelerated within the coronal plasma (the fast electron pre-beam) and those accelerated near or at the critical density surface (the fast electron main-beam). The former has considerably lower divergence and higher temperature than that of the main-beam with a half-angle of ∼20°. It contains up to 30% of the total fast electron energy absorbed into the target. The number, kinetic energy, and total energy of the fast electrons in the pre-beam are increased by an increase in density scalelength. With larger density scalelengths, the fast electrons heat a smaller cross sectional area of the target, causing the thinnest targets to reach significantly higher rear surface temperatures. Modelling indicates that the enhanced fast electron pre-beam associated with the large density scalelength interaction generates a magnetic field within the target of sufficient magnitude to partially collimate the subsequent, more divergent, fast electron main-beam.
Internal strain dependence of complex permeability of ball milled carbonyl iron powders in 2–18 GHz
Authors: He Jinghua , Wang Wei , Guan Jianguo
Published: May 2012

A series of the flake-like and sphere-like nanocrystalline carbonyl-iron powders (CIPs) were prepared by high energy ball milling raw CIPs for different times (t). Variations of the structure, morphology, microwave complex permeability, and static magnetization with t for the two kinds of CIPs have been investigated using x-ray diffraction, scanning electron microscopy, vector network analyzer, and vibrating sample magnetometer, respectively. The results show that with prolonging t, the nature resonance frequency (fr) and internal strain (〈ɛ〉) increase monotonously for the sphere-like nanocrystalline CIPs, while those fluctuate for the flake-like nanocrystalline CIPs. These phenomena are in accordance with the increasing fr with increasing 〈ɛ〉, suggesting that 〈ɛ〉 suppresses the domain wall displacement and promotes the gyromagnetic spin rotation. As a result, the competition between the domain wall displacement and the gyromagnetic spin rotation can be effectively controlled by 〈ɛ〉 in the as-milled nanocrystalline CIPs.
Perpendicular-magnetic-anisotropy CoFeB racetrack memory
Authors: Zhang Y. , Zhao W. S. , Ravelosona D. , Klein J.-O. , Kim J. V. , Chappert C.
Published: May 2012

Current-induced domain wall motion in magnetic nanowires drives the invention of a novel ultra-dense non-volatile storage device, called “racetrack memory.” Combining with magnetic tunnel junctions write and read heads, CMOS integrability and fast data access speed can also be achieved. Recent experimental progress showed that perpendicular-magnetic anisotropy (PMA) CoFeB could be a good candidate to build up racetrack memory and promise high performance like high-density (e.g., ∼1 F2/bit), fast-speed, and low-power beyond classical spin transfer torque memories. In this paper, we first present the design of PMA CoFeB racetrack memory and a spice-compatible model to perform mixed simulation with CMOS circuits. Its area, speed, and power dissipation performance has been simulated and evaluated based on different technology nodes.
Metal-like conductivity exhibited by triboelectrically deposited polyaniline (emeraldine base) particles on microtextured SiC surfaces
Authors: Bayer I. S. , Caramia V. , Biswas A. , Cingolani R. , Athanassiou A.
Published: May 2012

We demonstrate a simple and rapid way to deposit layers of polyaniline (emeraldine base) particles on flexible microtextured silicon carbide surfaces by contact charging them using a smooth dielectric rubber. Wetting of the layers by trifluoroacetic acid creates conductive, continuous polymeric films after drying. Pre-functionalization of the textured surfaces with anionic surfactants prevents particle coagulation during contact charging and decreases sheet resistance to metal-like levels (∼60 Ω/□). Conductivity of the films can be tuned by controlling the rate of acid evaporation. Conductive films are highly stable under ambient conditions and show no hysteresis when biased with zero delay-time.
Modeling charge transfer at organic donor-acceptor semiconductor interfaces
Authors: Çakir Deniz , Bokdam Menno , de Jong Michel P. , Fahlman Mats , Brocks Geert
Published: May 2012

We develop an integer charge transfer model for the potential steps observed at interfaces between donor and acceptor molecular semiconductors. The potential step can be expressed as the difference between the Fermi energy pinning levels of electrons on the acceptor material and holes on the donor material, as determined from metal-organic semiconductor contacts. These pinning levels can be obtained from simple density functional theory calculations.
Spectroscopic diagnostics of microhollow gas discharge in hydrogen
Authors: Spasojević Dj. , Cvejić M. , Šišović N. M. , Konjević N.
Published: May 2012

Hydrogen Balmer beta line profile from a microhollow gas discharge (MHGD) in hydrogen is used for diagnostics of cathode sheath (CS) parameters. The profile was recorded from a MHGD microhole (diameter 100 μm at narrow and 130 μm at wider side) of a gold-alumina-gold sandwich in the pressure range (100–400) mbars. The average electric field strength in CS (25–46) kV/cm and CS thickness (60–120) μm were determined by profile fitting with the aid of model recently developed and used in argon MHGD.
Spatio-temporal linear stability of double-diffusive two-fluid channel flow
Authors: Sahu Kirti Chandra , Govindarajan Rama
Published: May 2012

Absolute instabilities in shear flows can cause a catastrophic breakdown into a new unsteady state, or even into turbulence. We demonstrate that in a double-diffusive channel flow with a viscosity stratification across the channel, rapidly growing absolute instability may be obtained at Reynolds numbers of a few hundreds. The instability is much weaker in an equivalent single solute fluid with the same viscosity contrast, or even in one which is made up only of the more dangerous of the two diffusing species. This is a novel characteristic of double-diffusive systems driven by viscosity, rather than density variations. Convective instabilities too are stronger in the double-diffusive case.
Electrical breakdown of carbon nanotube devices and the predictability of breakdown position
Authors: Goswami Gopal Krishna , Nanda Karuna Kar
Published: May 2012

We have investigated electrical transport properties of long (>10 μm) multiwalled carbon nanotubes (NTs) by dividing individuals into several segments of identical length. Each segment has different resistance because of the random distribution of defect density in an NT and is corroborated by Raman studies. Higher is the resistance, lower is the current required to break the segments indicating that breakdown occurs at the highly resistive segment/site and not necessarily at the middle. This is consistent with the one-dimensional thermal transport model. We have demonstrated the healing of defects by annealing at moderate temperatures or by current annealing. To strengthen our mechanism, we have carried out electrical breakdown of nitrogen doped NTs (NNTs) with diameter variation from one end to the other. It reveals that the electrical breakdown occurs selectively at the narrower diameter region. Overall, we believe that our results will help to predict the breakdown position of both semiconducting and metallic NTs.
Causal effect of education on mortality in a quasi-experiment on 1.2 million Swedes
Authors: Lager Anton Carl Jonas , Torssander Jenny
Published: May 2012

In 1949–1962, Sweden implemented a 1-y increase in compulsory schooling as a quasi-experiment. Each year, children in a number of municipalities were exposed to the reform and others were kept as controls, allowing us to test the hypothesis that education is causally related to mortality. We studied all children born between 1943 and 1955, in 900 Swedish municipalities, with control for birth-cohort and area differences. Primary outcome measures are all-cause and cause-specific mortality until the end of 2007. The analyses include 1,247,867 individuals, of whom 92,351 died. We found lower all-cause mortality risk in the experimental group after age 40 [hazard ratio (HR) = 0.96, 95% confidence interval (CI) 0.93–0.99] but not before (HR = 1.03, 95% CI 0.98–1.07) or during the whole follow-up (HR = 0.98, 95% CI 0.95–1.01). After age 40, the experimental group had lower mortality from overall cancer, lung cancer, and accidents. In addition, exposed women had lower mortality from ischemic heart disease, and exposed men lower mortality from overall external causes. In analyses stratified for final educational level, we found lower mortality in the experimental group within the strata that settled for compulsory schooling only (HR = 0.94, 95% CI 0.89–0.99) and compulsory schooling plus vocational training (HR = 0.92, 95% CI 0.88–0.97). Thus, the experimental group had lower mortality from causes known to be related to education. Lower mortality in the experimental group was also found among the least educated, a group that clearly benefited from the reform in terms of educational length. However, all estimates are small and there was no evident impact of the reform on all-cause mortality in all ages.