bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the aetiology of diarrhoea in outpatients in 2007, Henan province, China
Authors: ZHU M. , CUI S. , LIN L. , XU B. , ZHAO J. , XIA S. , DENG W. , XIE Z. , ZHANG J. , WANG Z. , FENG Z. , YANG W. , RAN L.
Published: June 2012

The purpose of this study was to determine the aetiology of acute diarrhoea and improve knowledge of gastrointestinal pathogens in China. Faecal specimens from 1526 outpatients with diarrhoea were collected from 20 hospitals in Henan province and the prevalence of seven bacterial and five viral diarrhoeagenic pathogens were determined. Bacterial pathogens were recovered from 279/1526 (18·3%) stool specimens and viral pathogens were detected in 178/1526 (11·7%) stool specimens. The top five pathogenic species were diarrhoeagenicE. coli(n = 140, 9·2%), rotavirus (n = 79, 5·2%),Shigellaspp. (n = 69, 4·5%),Salmonellaspp. (n = 66, 4·3%) and norovirus (n = 56, 3·7%). The prevalence of pathogens showed correlation with age, season and clinical symptoms. Several dominant serotypes were identified inShigellaandSalmonellaisolates, and high prevalence of multiple drug-resistant isolates was observed in both species. This important information will have a significant effect on public health policy development and resource prioritization practices.
HYPOXIA IN PREGNANCY
Authors: PLAAT FELICITY , ARRANDALE LINDSAY
Published: June 2012

Hypoxia in pregnancy is rare, however the anatomical and physiological changes associated with pregnancy may exacerbate hypoxia and hypoxaemia arising from pathological processes.

In this review we seek to briefly outline the well recognised changes to the maternal airway and respiratory anatomy and physiology. We will discuss a hierarchical approach to the tests used in differential diagnoses, summarise the physical principles behind commonly used tests and identify pitfalls and considerations in their use in the obstetric population. Some of the more commonly seen pathological states that may cause hypoxia in pregnancy will be discussed.
High School Allied Health Students and Their Exposure to the Profession of EMS
Authors: Holloman Joshua B. , Hubble Michael W.
Published: June 2012

Introduction

Ensuring a stable Emergency Medical Services (EMS) workforce is a growing concern, and effective recruiting strategies are needed to expose young adults to the EMS profession. The objective of this study was to assess the exposure of high school allied health students to EMS as a career option, as well as measure their attitudes and beliefs about the EMS profession.

Hypothesis

Few high school allied health students are exposed to EMS educational and career opportunities.

Methods

A convenience sample of allied health students in a rural high school system was surveyed about exposure to EMS, career intentions, factors impacting career decisions, and attitudes and beliefs about EMS. Descriptive statistics were calculated, and intention to pursue an EMS career was modeled using logistic regression.

Results

Of 171 students enrolled in allied health courses across six high schools, 135 (78.9%) agreed to participate; 85.2% were female. Almost all (92.6%) respondents intended to pursue a health career, but only 43.0% reported that their allied health course exposed them to EMS as a profession. Few participants (37.7%) were knowledgeable about EMS associate degree or baccalaureate degree (27.4%) programs. Only 20.7% of the respondents intended to pursue EMS as a career, although 46.0% wanted to learn more about the profession. Most (68.2%) students expressed interest in an emergency medical technician (EMT) course if one were offered, and 80.0% were interested in a ride-along program. Independent predictors of pursuing an EMS career included exposure to EMS outside of high school (OR = 7.4, 95% CI = 1.7-30.4); media influence on career choice (OR = 9.6, 95% CI = 1.8-50.1); and the belief that EMS was mentally challenging (OR = 15.9, 95% CI = 1.1-216.6). Negative predictors included the beliefs that an EMS career was stimulating (OR = 0.05, 95% CI = 0.00-0.53) and physically challenging (OR = 0.06, 95% CI = 0.00-0.63); as well as prior exposure to an EMS job advertisement (OR = 0.14, 0.03-0.53).

Conclusions

Overall, there was a lack of exposure to career and educational options in EMS among allied health students in the school system studied, and few students intended to pursue an EMS career after graduation. However, the majority of students indicated they would like to learn more about EMS, and would enroll in an EMT course and ride-along program if available. These findings suggest that, with exposure to the profession, more allied health students could choose EMS as a career.

Holloman JB, Hubble MW. High school allied health students and their exposure to the profession of EMS.Prehosp Disaster Med.2012;27(3):1-7.
EXPLORING HAWTREY’S SOCIAL PHILOSOPHY THROUGH HIS UNPUBLISHED BOOK,RIGHT POLICY
Authors: HIRAI TOSHIAKI
Published: June 2012

The purpose of this paper is to reconstruct and evaluate, among other issues, Hawtrey’s social philosophy.

Hawtrey’s system as a whole is composed of the two distinct and yet interrelated subsystems: philosophy and social philosophy. The former has three components: the theory of evolution and rationalization; the theory of aspects; and Moorean ethics. The latter has two components: his conception of society in general; and his perception of capitalistic economy as one type of society.

We then examine three problematic elements connected with Hawtrey’s system: epistemology in Hawtrey and Moore; plus products and the market; and the ruler and the public.
THE MATHEMATICAL TURN IN ECONOMICS: WALRAS, THE FRENCH MATHEMATICIANS, AND THE ROAD NOT TAKEN
Authors: TURK MICHAEL H.
Published: June 2012

One of the pivotal moments in the move toward mathematizing economics occurred at the turn of the twentieth century, with Leon Walras as perhaps its most ardent champion. Yet, there is no small irony here, in that the leading French mathematicians to whom Walras turned to buttress and defend the case for a mathematical economics, especially Henri Poincare and Emile Picard, laid out reservations to the scope of this mathematizing program. They even pointed to matters, including the hold of the past on future events and hysteresis, a subject already in the discourse of mathematical physicists, which might have fashioned economics differently from the neoclassical mold being formed. This alternate pathway, though, was not pursued at the time.
THE ORGANIZATIONAL PROPERTIES OF MONEY: GUSTAVO DEL VECCHIO’S THEORY
Authors: TUSSET GIANFRANCO
Published: June 2012

The integration of money into the Walrasian general equilibrium scheme is an age-old and intricate issue. One of the first attempts was made by Gustavo Del Vecchio, who, in the early twentieth century, built a theory of circulation that considered money as a medium of exchange, and investigated its organizational and social aspects in depth. Del Vecchio developed a theory of monetary service grounded on the distinction between individual and social utility of money. Moreover, he stated that money, credit, accumulation, and crisis could no longer be theorized with time omitted, and this induced him to formulate dynamic statements that put forward claims about money as a store of value. The organizational and social dimensions of money, time, and uncertainty were all important and interconnected aspects in Del Vecchio’s scientific inquiry, for they all sprang from his conceptualization of money as a medium of exchange.
A SMS normalization system integrating multiple grammatical resources
Authors: OLIVA J. , SERRANO J. I. , DEL CASTILLO M. D. , IGESIAS Á.
Published: June 2012

SMS language presents special phenomena and important deviations from natural language. Every day, an impressive amount of chat messages, SMS messages, and e-mails are sent all over the world. This widespread use makes important the development of systems that normalize SMS language into natural language. However, typical machine translation approaches are difficult to adapt to SMS language because of many irregularities that are shown by this kind of language. This paper presents a new approach for SMS normalization that combines lexical and phonological translation techniques with disambiguation algorithms at two different levels: lexical and semantic. The method proposed does not depend on big annotated corpus, which is difficult to build and is applied in two different domains showing its easiness of adaptation across different languages and domains. The results obtained by the system outperform some of the existing methods of SMS normalization despite the fact that the Spanish language and the corpus created have some features that complicate the normalization task.
Further Validation of a Chinese Version of the Obsessive-Compulsive Inventory-Revised
Authors: Chasson Gregory S. , Tang Suqin , Gray Bradley , Sun Hongwei , Wang Jianping
Published: June 2012

Background: There has been an increased effort to understand the nature of obsessive-compulsive disorder (OCD) in non-Western cultures. In particular, growing research has examined OCD in China, but there are no comprehensive instruments that measure both OCD severity and heterogeneity for characterizing samples. Aims: A validated, comprehensive measure that could be used in China would provide researchers with a useful instrument for evaluating severity and heterogeneity of OCD in a non-Western culture, allowing researchers to better understand the universal and cultural components that play a role in the nature of OCD. Method: The current investigation presents data on the reliability and validity of a Mandarin translation of the Obsessive-Compulsive Inventory-Revised (CH-OCI) using both a student (n = 1950) and clinical sample (n = 50 patients with OCD; n = 50 patients with anxiety as a comparison group). Results: Results support the factor structure, convergent and discriminant validity, criterion-related validity, test-retest reliability, and internal consistency of the CH-OCI. Conclusions: Validation of the instrument permits researchers and clinicians to measure OCD presentation in Mandarin-speaking samples.
Selective Attention and the Three-Process Memory Model for the Interpretation of Verbal Free Recall in Amyotrophic Lateral Sclerosis
Authors: Christidi Foteini , Zalonis Ioannis , Smyrnis Nikolaos , Evdokimidis Ioannis
Published: June 2012

The present study investigates selective attention and verbal free recall in amyotrophic lateral sclerosis (ALS) and examines the contribution of selective attention, encoding, consolidation, and retrieval memory processes to patients’ verbal free recall. We examined 22 non-demented patients with sporadic ALS and 22 demographically related controls using Stroop Neuropsychological Screening Test (SNST; selective attention) and Rey Auditory Verbal Learning Test (RAVLT; immediate & delayed verbal free recall). The item-specific deficit approach (ISDA) was applied to RAVLT to evaluate encoding, consolidation, and retrieval difficulties. ALS patients performed worse than controls on SNST (p < .001) and RAVLT immediate and delayed recall (p < .001) and showed deficient encoding (p = .001) and consolidation (p = .002) but not retrieval (p = .405). Hierarchical regression analysis revealed that SNST and ISDA indices accounted for: (a) 91.1% of the variance in RAVLT immediate recall, with encoding (p = .016), consolidation (p < .001), and retrieval (p = .032) significantly contributing to the overall model and the SNST alone accounting for 41.6%; and (b) 85.2% of the variance in RAVLT delayed recall, with consolidation (p < .001) and retrieval (p = .008) significantly contributing to the overall model and the SNST alone accounting for 39.8%. Thus, selective attention, encoding, and consolidation, and to a lesser extent of retrieval, influenced both immediate and delayed verbal free recall. Concluding, selective attention and the memory processes of encoding, consolidation, and retrieval should be considered while interpreting patients’ impaired free recall. (JINS, 2012, 18, 1–10)
A NOTE ON THE REAL EFFECTS OF MONETARY SHOCKS: A LIMITED PARTICIPATION MODEL
Authors: Gutiérrez Pedro J. , Palmero Carlos R.
Published: June 2012

This paper presents a monetary stochastic general equilibrium model that allows the real cyclical movements of the economy to be explained as a consequence of exogenous monetary, public spending, and technology shocks. The model is calibrated and simulated, and its accuracy in replicating the cyclical movements in the real variables is compared with that of the standard real business cycle (RBC) model. We find that our model fits the observed data better than the existing RBC models, especially for the labor market.
The association between dairy food intake and the incidence of diabetes in Australia: the Australian Diabetes Obesity and Lifestyle Study (AusDiab)
Authors: Grantham Narelle M , Magliano Dianna J , Hodge Allison , Jowett Jeremy , Meikle Peter , Shaw Jonathan E
Published: June 2012

Objective

Several studies have suggested that dairy food may reduce the risk of obesity and metabolic abnormalities but few have been able to conclusively demonstrate that it reduces the risk of diabetes. The aim of the present analysis was to investigate if dairy food intake independently reduces the risk of diabetes.

Design

The Australian Diabetes Obesity and Lifestyle Study (AusDiab) is a national, population-based, prospective survey conducted over 5 years. Baseline measurements included a 121-item FFQ, anthropometrics and an oral glucose tolerance test.

Setting

Forty-two randomly selected clusters across Australia.

Subjects

Adults aged ≥25 years who participated in the baseline survey and returned to follow-up 5 years later.

Results

A total of 5582 participants with complete data were eligible for analysis, 209 of whom had incident diabetes. Compared with men in the first tertile of dairy food intake, men in the third tertile had a significantly reduced risk of developing diabetes after adjustment for age, sex, total energy intake, family history of diabetes, education, physical activity, smoking status, fasting serum TAG and HDL cholesterol, systolic blood pressure, waist circumference and hip circumference (OR = 0·53, 95 % CI 0·29, 0·96;P= 0·033). A similar non-significant association was observed in women.

Conclusions

Dietary patterns that incorporate high intakes of dairy food may reduce the risk of diabetes among men. Further investigation into the relationship between dairy food intake and diabetes needs to be undertaken to fully understand the potential mechanism of this observation.
THE LATIN AMERICANIZATION OF RACE RELATIONS IN THE UNITED STATES
Authors: Almaguer Tomás
Published: June 2012

Much has been written lately in both the popular and academic press about the “Browning” of America and the changing nature of race and ethnic relations in the United States. This has been largely the result of the precipitous increase in the Latino population and its profound change on the demographic landscape in the United States. For example, the U.S. Bureau of the Census (2010) has shown the Latino population grew from 35.3 million in 2000 to over 50 million in 2010 (p. 3). The Latino population now represents 16% of the total U.S. population and has surpassed African Americans as the largest racial-ethnic population at the turn of the century. Recent demographic projections calculate that by 2050 the Latino population will increase to an estimated 128 million or 29% of the national total. As Rumbaut (2009) writes, in that year it will exceed the combined total of all other racial minorities (primarily African American and Asian) in the United States (p. 17).
INTRODUCTION
Authors: Lamont Michèle , Welburn Jessica S. , Fleming Crystal M.
Published: June 2012

It is particularly fitting thatDu Bois Reviewwould publish a special feature titled “Varieties of Responses to Stigmatization: Macro, Meso, and Micro Dimensions.” In many ways, we can consider the management of stigma to be a quintessentially Du Bois topic. In his classical writings on double consciousness, this pioneering social theorist (2007) captured the complex psychological experience of managing a life where one feels divided within oneself. He focused specifically on African American identity defined by the tension of being two at once (American and Black): “The Negro ever feels his two-ness—an American, a Negro; two souls, two thoughts, two unreconciled strivings; two warring ideals in one dark body, whose dogged strength alone keeps it from being torn asunder” (p. 3).
HOMELAND TOURISM, EMOTION, AND IDENTITY LABOR
Authors: Taylor Judith , Levi Ron , Dinovitzer Ronit
Published: June 2012

Concern over intergenerational ethnic continuity, with members of minority groups seeking to ensure that youth become invested in and committed to religious, cultural, or ethnic identities, is long-standing and inherent to group boundary formation. In recent years, this concern has been particularly pronounced in the North American Jewish community, with socialization and retention of Jewish young adults emerging as one of its central preoccupations. This emphasis on Jewish continuity emerged as a central concern following the legacy of experiences with anti-Semitism and discrimination. The most significant program to emerge from this agenda is Taglit-Birthright Israel, a program that has provided over 250,000 free ten-day trips to Israel for Jewish young adults from over fifty countries. Homeland tours of this sort are increasingly common across diasporic groups, and this paper attends to the emotional work that underlies collective identity formation in these tours. Through focus groups with Taglit-Birthright participants, we find that these tours engage and mobilize competing sets of emotions, and that tour members experience dimensions of closeness and distance at once. The result is that participants are engaged in a form of identity labor: they grapple with the questions of how they should affiliate as Jews, and how they can forge an identity that carves a role for themselves in the diaspora. Drawing on the sociological concept of ambivalence, we find that collective identity is successfully forged in these trips by interrupting the notion of effortless ethnic belonging, and providing participants with a deeper understanding of the commitment required for intra-ethnic group identification and attachments.
“SOCIALLY MIXED” PUBLIC HOUSING REDEVELOPMENT AS A DESTIGMATIZATION STRATEGY IN TORONTO'S REGENT PARK
Authors: Dunn James R.
Published: June 2012

Over the last two decades decision makers have sought to address problems with large concentrations of poverty and minority ethnoracial groups in the cities of Western Europe and the Anglo-American world that are the direct result of the manner in which public housing was built in the early postwar era. The United States, Canada, the United Kingdom, and Australia have developed programs that introduce “social mix” into such public housing developments. These initiatives are designed to alter the social dynamics of places with high levels of concentrated poverty and ethnoracial minority groups that are believed to magnify the disadvantages of poverty and marginalization. In this paper, I argue that this is a destigmatization strategy, but not the same kind of destigmatization strategy that has been described in the literature. Using the example of Toronto's Regent Park, a large public housing development near downtown, I develop a research agenda for understanding the gap between a quasi-state agency's efforts to destigmatize public housing sites (“place destigmatization”) and the everyday destigmatization practices and experiences of residents (“personal destigmatization”). The paper begins with a review of the putative mechanisms linking socially mixed public housing redevelopment and outcomes for residents, including social capital, social control, role modelling, and changes to the political economy of place. This review finds little evidence of these effects in the literature. Consequently, I argue for an inductive approach to the study of the outcomes of social mix, rather than the common practice of judging such outcomes against the benchmark of close, intimate relationships between new, middle-class residents and existing public housing residents. I further argue that the “normalization” of the built form that is a major part of socially mixed redevelopment is a form of place destigmatization, and may alter both material practices and representational practices related to stigma, which have very real effects on the everyday experience of residents.
RACE, GENDER, AND THE POLITICAL CONFLATION OF BIOLOGICAL AND SOCIAL ISSUES
Authors: Roberts Dorothy E.
Published: June 2012

In March of 1969, a Black man from Detroit named Abdul-Rasheed Karim arrived at Ionia State Hospital for the Criminally Insane in Ionia, Michigan, after spending two years locked up in prison and a psychiatric ward for a fight that started when he was assaulted by three White boys, then brutalized by the police who responded. Mr. Karim, who suffered two broken ribs, a cracked tooth, and a deep skull laceration, made the mistake of hitting one of the officers who were beating him with clubs. As Metzl quotes, the clinical evaluation that led to Mr. Karim's transfer to Ionia noted “cultural retardation is thus a significant factor in his schizophrenic disease” because he had been “socialized toward ghetto survival” (p. 143) as a child. The doctor interpreted Mr. Karim's Islamic beliefs as “religious delusions,” writing, “his identification with the Black Muslim group is a projection of his feelings of inadequacy” (p. 143). Once at Ionia, doctors treated Mr. Karim's hostility toward authority figures by confining him to a maximum supervision ward where he was injected daily with escalating doses of antipsychotic drugs.
RACE AND AFFIRMING OPPORTUNITY IN THE BARACK OBAMA ERA
Authors: Wilson William Julius
Published: June 2012

I first discuss the Obama administration's efforts to promote racial diversity on college campuses in the face of recent court challenges to affirmative action. I then analyze opposition in this country to “racial preferences” as a way to overcome inequality. I follow that with a discussion of why class-based affirmative action, as a response to cries from conservatives to abolish “racial preferences,” would not be an adequate substitute for race-based affirmative action. Instead of class-based affirmative action, I present an argument for opportunity enhancing affirmative action programs that rely on flexible, merit-based criteria of evaluation as opposed to numerical guidelines or quotas. Using the term “affirmative opportunity” to describe such programs, I illustrate their application with three cases: the University of California, Irvine's revised affirmative action admissions procedure; the University of Michigan Law School's affirmative action program, which was upheld by the Supreme Court in 2003; and the hiring and promotion of faculty of color at colleges and universities as seen in how I myself benefited from a type of affirmative action based on flexible merit-based criteria at the University of Chicago in the early 1970s. I conclude by relating affirmative opportunity programs for people of color to the important principle of “equality of life chances.”
Are institutional transplants viable? An examination in light of the proposals by Jeremy Bentham
Authors: COUYOUMDJIAN JUAN PABLO
Published: June 2012

The problem of institutional transplantation is an important issue. In Jeremy Bentham's work, we find practical as well as theoretical proposals regarding this problem. Here, we view his work as an invitation to reflect on the overall nature of the question of institutional design and transplantation. The transfer of institutions requires knowledge of ‘place and time’ that will allow for an accommodation of the transferred institutions to their new soil. However, an awareness of this type of knowledge and thus relying on its actually being available is not viable from a practical point of view. This is due to the fact that the core of informal institutions is tacit, which imposes a fundamental constraint on the process of institutional transplantation; informal norms must co-exist with formal rules, and such merging requires some accommodation of both types of rules.
Will to power? Intra-party conflict in social democratic parties and the choice for neoliberal policies in Germany, the Netherlands and Spain (1980–2010)
Authors: Marx Paul , Schumacher Gijs
Published: June 2012

Why do social democrats choose neoliberal labor market policies? Since social democrats are typically punished for welfare state retrenchment and because these policies do not equate well with social democratic egalitarian principles, it is difficult to see what they gain from it. We argue that, depending on the intra-party balance of power between activists and leaders, some parties are office-seeking, whereas others are policy-seeking. This behavioral difference explains why some parties are responsive to environmental incentives such as the economy and public opinion (office-seeking parties) and others are responsive to policy-motivated activists (policy-seeking parties). Using three case studies of social democratic parties (Germany, the Netherlands and Spain) in the period 1980–2010, we analyze when and why these parties introduced neoliberal reforms. The study shows that office-seeking parties introduce neoliberal measures if the risk of losing votes due to an underperforming economy becomes larger than the risk of losing votes due to the mobilization of unions and opposition parties. Policy-seeking social democrats retain a social democratic ideology, unless prolonged failure to win office empowers pragmatic leaders to push through office-seeking strategies.
Grain‐size properties and organic‐carbon stock of Yedoma Ice Complex permafrost from the Kolyma lowland, northeastern Siberia
Authors: Strauss Jens , Schirrmeister Lutz , Wetterich Sebastian , Borchers Andreas , Davydov Sergei P.
Published: June 2012

The organic carbon stock in permafrost is of increasing interest in environmental research, because during the late Quaternary a large pool of organic carbon accumulated in the sedimentary deposits of arctic permafrost. Because of its potential to degrade and release organic carbon, the organic‐matter inventory of Yedoma Ice Complex deposits is relevant to current concerns about the effects of global warming. In this context, it is essential to improve the understanding of preserved carbon quantities and characteristics. The paper aims to clarify the Yedoma Ice Complex origin, and to develop an approach for volumetric organic‐matter quantification. Therefore, we analyzed the grain size and the organic‐matter characteristics of the deposits exposed at the stratigraphic key site Duvanny Yar (lower Kolyma River, northeast Siberia). A distinct bimodal grain‐size distribution confirms a polygenetic origin of the frozen sediments from a floodplain environment. The total organic‐carbon content averages 1.5 ± 1.4 wt% while the volumetric organic‐carbon content averages 14 ± 8 kg/m3. However, large‐scale extrapolations for Yedoma Ice Complex deposits in general are not reasonable yet because of their rather unclear spatial distribution. We conclude that Yedoma Ice Complex formation at Duvanny Yar was dominated by water‐related (alluvial/fluvial/lacustrine) as well as aeolian processes. The total organic‐carbon content of the studied deposits is low if compared to other profiles, but it is still a significant pool.
Magnetic petrology of high Fe‐Ti eclogites from the CCSD main hole: Implications for subduction‐zone magnetism
Authors: Liu Qingsheng , Frost B. Ronald , Wang Hongcai , Zheng Jianping , Zeng Qingli , Jin Zhenmin
Published: June 2012

The high Fe‐Ti eclogites with exsolved lamellar in 530–600 m depths from the Chinese Continental Scientific Drilling (CCSD) main hole in the Sulu Ultra‐High Pressure (UHP) metamorphic belt, eastern China, record an anomalously high susceptibility (κ), natural remanent magnetization (NRM) and Köenigsberger ratio Q (NRM/Ji, Ji is induced magnetization). This provides us with a good opportunity to study the effects of magnetic minerals and exsolution lamellae on the magnetic properties of deep rocks. In this paper, we have measured systematically magnetic properties and mineral assemblage and structure for three special samples (No. 83, No.86 and No.89). Results show that these Fe‐Ti‐rich eclogites are the result of the fine‐grained (titano)‐magnetite exsolution in pyroxene and lamellar structure consisting of finely interlayered ilmenite and hematite in exsolved hemo‐ilmenite. We found that the dominant Fe‐bearing oxide minerals in samples studied are ilmenite, hematite (Hem + Ilm up to 25%), little (titano)magnetite and pyrite. The ferromagnetic susceptibility is mainly controlled by fine grained (titano)magnetite and NRM is closely related to the exsolved lamellar structure. We hence propose that the anomalous magnetism of these eclogites observed in our samples is the result of exsolution from homogenous pyroxene and ilmeno‐hematite during cooling and decompression processes. These Fe‐Ti‐rich eclogites might be one of the sources of high‐magnetic anomalies observed in the Sulu subduction zone, eastern China.
Numerical simulations of convection in crystal‐bearing magmas: A case study of the magmatic system at Erebus, Antarctica
Authors: Molina Indira , Burgisser Alain , Oppenheimer Clive
Published: June 2012

The sustained heat and gas output from Erebus volcano reflects a regime of magma convection that we investigate here using a bi‐phase (melt and crystals), fluid dynamical model. Following validity and verification tests of the model, we carried out four single‐phase and three bi‐phase numerical 30‐year‐ simulations, in an idealized 2D geometry representing a lava lake cooled from above and a reservoir heated from below that are linked by a 4‐to‐10–m‐diameter conduit. We tested the effects of crystals on convection while changing conduit size and the system boundaries from closed to open. Neglecting crystal settling yields only a limited number of features, i.e., (i) the formation of a central instability, (ii) the average temperature evolution, and (iii) the average velocity range of the surface flow motion. Bi‐phase simulations show that while crystals are quite efficiently transported by the liquid phase a small decoupling reflecting their large size (5 cm) results in settling. This leads to more complex circulation patterns and enhances the vigor of fluid motion. A sufficiently large conduit sustains convection and retains 6 and 20% of crystals in suspension, for a closed and open system, respectively. Model outputs do not yet correspond well with field observations of Erebus lava lake (e.g., real surface velocities are much faster than those modeled), suggesting that exsolved volatiles are an important source of buoyancy.
Abrupt changes of intermediate water properties on the northeastern slope of the Bering Sea during the last glacial and deglacial period
Authors: Rella Stephan F. , Tada Ryuji , Nagashima Kana , Ikehara Minoru , Itaki Takuya , Ohkushi Ken'ichi , Sakamoto Tatsuhiko , Harada Naomi , Uchida Masao
Published: June 2012

Millennial‐scale variability in the behavior of North Pacific Intermediate Water during the last glacial and deglacial period, and its association with Dansgaard‐Oeschger (D‐O) cycles and Heinrich events, are examined based on benthic foraminiferal oxygen and carbon isotopes (δ18Obf and δ13Cbf) and %CaCO3 using a sediment core recovered from the northeastern slope of the Bering Sea. A suite of positive δ18Obf excursions at intermediate depths of the Bering Sea, which seem at least in part associated with increases in the δ18Obf gradients between the Bering and Okhotsk Seas, suggest the Bering Sea as a proximate source of intermediate water during several severe stadial episodes in the last glacial and deglacial period. Absence of such δ18Obf gradients during periods of high surface productivity in the Bering and Okhotsk Seas, which we correlate to D‐O interstadials, suggests a reduction in intermediate water production in the Bering Sea and subsequent introduction of nutrient‐rich deep waters from the North Pacific into intermediate depths of the Bering Sea. We argue that a reorganization of atmospheric circulation in the high‐latitude North Pacific during severe cold episodes in the last glacial and deglacial period created favorable conditions for brine rejection in the northeastern Bering Sea. The resulting salinity increase in the cold surface waters could have initiated intermediate (and deep) water formation that spread out to the North Pacific.
Self‐inhibiting growth of the Greenland Ice Sheet
Authors: Langen P. L. , Solgaard A. M. , Hvidberg C. S.
Published: June 2012

The build‐up of the Greenland Ice Sheet (GrIS) from ice‐free conditions is studied in an ice sheet model (ISM) driven by fields from an atmospheric general circulation model (GCM) to demonstrate the importance of coupling between the two components. Experiments where the two are coupled off‐line are augmented by one where an intermediate ice sheet configuration is coupled back to the GCM. Forcing the ISM with GCM fields corresponding to the ice‐free state leads to extensive regrowth which, however, is halted when the intermediate recoupling step is included. This inhibition of further growth is due to a Föhn effect of moist air parcels being lifted over the intermediate ice sheet and arriving in the low‐lying Greenland interior with high temperatures. This demonstrates that two‐way coupling between the atmosphere and the ice sheet is essential for understanding the dynamics and that large scale conditions cooler than those of today may be necessary for the GrIS to regrow to the present volume.
Whistler anisotropy instability with a cold electron component: Linear theory
Authors: Gary S. Peter , Liu Kaijun , Denton Richard E. , Wu Shuo
Published: June 2012

The whistler anisotropy instability is driven by an electron temperature anisotropy T⊥/T∥ > 1 where ⊥ and ∥ denote directions perpendicular and parallel, respectively, to the background magnetic field Bo. Here kinetic linear theory in a magnetized, homogeneous, collisionless plasma model is used to study this instability when the electron velocity distribution may be represented as the sum of a hot, anisotropic bi‐Maxwellian and a cold, isotropic component. The critical β∥e, the value at which the maximum growth rate of the instability changes from propagation parallel to Bo to oblique propagation, decreases with increasing nc/ne, where nc is the cold electron density and ne is the total electron density. At parallel propagation the maximum growth rate increases with nc/ne up to nc/ne ≃ 0.8, but then diminishes with further increases of the relative cold electron density. Introduction of a cold electron component can reduce the hot electron anisotropy necessary to excite this instability by up to a factor of 2.
Generation process of magnetic decreases and the resulting kinetic effects on energetic particles within corotating interaction regions
Authors: Tsubouchi K.
Published: June 2012

One‐dimensional hybrid simulations are performed to examine the formation mechanism of magnetic decrease (MD) structures within corotating interaction regions (CIRs) and their effect on the energetic particle profiles associated with the shock acceleration at the CIR boundaries. As the source of MD formation, Alfvén wave structures propagating in the fast solar wind, which make depressions in the magnetic field magnitude after passing through the CIR reverse shock, are taken into account. The observed MD properties of the simultaneous density and pressure enhancement are confirmed. The key process of reducing the field intensity is the incidence of Alfvénic field variations in the anisotropic plasma (P⊥ > P∥) of the reverse shock downstream. Directional changes in the magnetic field induce energy exchange between parallel and perpendicular components, leading to isotropization and adiabatic field reduction. Magnetic mirror points consequently form, where field‐aligned streams further intensify and particles accumulate in MDs. The capture of particles by MDs delays the reverse shock evolution. Therefore, it is expected that MDs will reduce the CIR dimension and lower the efficiency of particle acceleration at CIR shocks.
The impact of helium on thermosphere mass density response to geomagnetic activity during the recent solar minimum
Authors: Thayer J. P. , Liu X. , Lei J. , Pilinski M. , Burns A. G.
Published: June 2012

High‐resolution mass density observations inferred from accelerometer measurements on the CHAMP and GRACE satellites are employed to investigate the thermosphere mass density response with latitude and altitude to geomagnetic activity during the recent solar minimum. Coplanar orbital periods in February 2007 and December 2008 revealed the altitude and latitude response in thermosphere mass density for their respective winter hemispheres was influenced by the relative amount of helium and oxygen present. The CHAMP‐to‐GRACE (C/G) mass density ratio depends on two terms; the first proportional to the ratio of the mean molecular weight to temperature and the second proportional to the vertical gradient of the logarithmic mean molecular weight. For the relative levels of helium and oxygen in February 2007, the winter hemisphere C/G mass density response to geomagnetic activity, although similar to the summer hemisphere, was caused predominantly by changes in the vertical gradient of the logarithmic mean molecular weight. In December 2008, the significant presence of helium caused the mean molecular weight changes to exceed temperature changes in the winter hemisphere leading to an increase in the C/G ratio with increasing geomagnetic activity, in opposition to the decrease observed in the summer hemisphere that was caused primarily by temperature changes. The observed behavior is indicative of composition effects influencing the mass density response and the dynamic action of the oxygen to helium transition region in both latitude and altitude will lead to complex behaviors in the mass density at GRACE altitudes throughout the extended solar minimum from 2007 to 2010.
A model‐data comparison of gross primary productivity: Results from the North American Carbon Program site synthesis
Authors: Schaefer Kevin , Schwalm Christopher R. , Williams Chris , Arain M. Altaf , Barr Alan , Chen Jing M. , Davis Kenneth J. , Dimitrov Dimitre , Hilton Timothy W. , Hollinger David Y. , Humphreys Elyn , Poulter Benjamin , Raczka Brett M. , Richardson Andrew D. , Sahoo Alok , Thornton Peter , Vargas Rodrigo , Verbeeck Hans , Anderson Ryan , Baker Ian , Black T. Andrew , Bolstad Paul , Chen Jiquan , Curtis Peter S. , Desai Ankur R. , Dietze Michael , Dragoni Danilo , Gough Christopher , Grant Robert F. , Gu Lianhong , Jain Atul , Kucharik Chris , Law Beverly , Liu Shuguang , Lokipitiya Erandathie , Margolis Hank A. , Matamala Roser , McCaughey J. Harry , Monson Russ , Munger J. William , Oechel Walter , Peng Changhui , Price David T. , Ricciuto Dan , Riley William J. , Roulet Nigel , Tian Hanqin , Tonitto Christina , Torn Margaret , Weng Ensheng , Zhou Xiaolu
Published: June 2012

Accurately simulating gross primary productivity (GPP) in terrestrial ecosystem models is critical because errors in simulated GPP propagate through the model to introduce additional errors in simulated biomass and other fluxes. We evaluated simulated, daily average GPP from 26 models against estimated GPP at 39 eddy covariance flux tower sites across the United States and Canada. None of the models in this study match estimated GPP within observed uncertainty. On average, models overestimate GPP in winter, spring, and fall, and underestimate GPP in summer. Models overpredicted GPP under dry conditions and for temperatures below 0°C. Improvements in simulated soil moisture and ecosystem response to drought or humidity stress will improve simulated GPP under dry conditions. Adding a low‐temperature response to shut down GPP for temperatures below 0°C will reduce the positive bias in winter, spring, and fall and improve simulated phenology. The negative bias in summer and poor overall performance resulted from mismatches between simulated and observed light use efficiency (LUE). Improving simulated GPP requires better leaf‐to‐canopy scaling and better values of model parameters that control the maximum potential GPP, such asεmax (LUE), Vcmax (unstressed Rubisco catalytic capacity) or Jmax (the maximum electron transport rate).
Temporal dynamics of blue and green virtual water trade networks
Authors: Konar M. , Dalin C. , Hanasaki N. , Rinaldo A. , Rodriguez‐Iturbe I.
Published: June 2012

Global food security increasingly relies on the trade of food commodities. Freshwater resources are essential to agricultural production and are thus embodied in the trade of food commodities, referred to as “virtual water trade.” Agricultural production predominantly relies on rainwater (i.e., “green water”), though irrigation (i.e., “blue water”) does play an important role. These different sources of water have distinctly different opportunity costs, which may be reflected in the way these resources are traded. Thus, the temporal dynamics of the virtual water trade networks from these distinct water sources require characterization. We find that 42 × 109 m3 blue and 310 × 109 m3 green water was traded in 1986, growing to 78 × 109 m3 blue and 594 × 109 m3 green water traded in 2008. Three nations dominate the export of green water resources: the USA, Argentina, and Brazil. As a country increases its export trade partners it tends to export relatively more blue water. However, as a country increases its import trade partners it does not preferentially import water from a specific source. The amount of virtual water that a country imports by increasing its import trade partners has been decreasing over time, with the exception of the soy trade. Both blue and green virtual water networks are efficient: 119 × 109 m3 blue and 105 × 109 m3 green water were saved in 2008. Importantly, trade has been increasingly saving water over time, due to the intensification of crop trade on more water‐efficient links.
Monitoring of Vibrio harveyi quorum sensing activity in real time during infection of brine shrimp larvae
Authors: Defoirdt Tom , Sorgeloos Patrick
Published: June 2012

Quorum sensing, bacterial cell-to-cell communication, has been linked to the virulence of pathogenic bacteria. Indeed, in vitro experiments have shown that many bacterial pathogens regulate the expression of virulence genes by this cell-to-cell communication process. Moreover, signal molecules have been detected in samples retrieved from infected hosts and quorum sensing disruption has been reported to result in reduced virulence in different host–pathogen systems. However, data on in vivo quorum sensing activity of pathogens during infection of a host are currently lacking. We previously reported that quorum sensing regulates the virulence of Vibrio harveyi in a standardised model system with gnotobiotic brine shrimp (Artemia franciscana) larvae. Here, we monitored quorum sensing activity in Vibrio harveyi during infection of the shrimp, using bioluminescence as a read-out. We found that wild-type Vibrio harveyi shows a strong increase in quorum sensing activity early during infection. In this respect, the bacteria behave remarkably similar in different larvae, despite the fact that only half of them survive the infection. Interestingly, when expressed per bacterial cell, Vibrio harveyi showed around 200-fold higher maximal quorum sensing-regulated bioluminescence when associated with larvae than in the culture water. Finally, the in vivo quorum sensing activity of mutants defective in the production of one of the three signal molecules is consistent with their virulence, with no detectable in vivo quorum sensing activity in AI-2- and CAI-1-deficient mutants. These results indicate that AI-2 and CAI-1 are the dominant signals during infection of brine shrimp.
MMP proteolysis of the human extracellular matrix protein aggrecan is mainly a process of normal turnover
Authors: Struglics André , Hansson Maria
Published: June 2012

Although it has been shown that aggrecanases are involved in aggrecan degradation, the role of MMP (matrix metalloproteinase) aggrecanolysis is less well studied. To investigate MMP proteolysis of human aggrecan, in the present study we used neoepitope antibodies against MMP cleavage sites and Western blot analysis to identify MMP-generated fragments in normal and OA (osteoarthritis/osteoarthritic) cartilage, and in normal, knee injury and OA and SF (synovial fluid) samples. MMP-3 in vitro digestion showed that aggrecan contains six MMP cleavage sites, in the IGD (interglobular domain), the KS (keratan sulfate) region, the border between the KS region and CS (chondroitin sulfate) region 1, the CS1 region, and the border between the CS2 and the G3 domain, and kinetic studies showed a specific order of digestion where the cleavage between CS2 and the G3 domain was the most preferred. In vivo studies showed that OA cartilage contained (per dry weight) 3.4-fold more MMP-generated FFGV fragments compared with normal cartilage, and although aggrecanase-generated SF-ARGS concentrations were increased 14-fold in OA and knee-injured patients compared with levels in knee-healthy reference subjects, the SF-FFGV concentrations did not notably change. The results of the present study suggest that MMPs are mainly involved in normal aggrecan turnover and might have a less-active role in aggrecan degradation during knee injury and OA.
Spatiotemporal regulation of PKC via interactions with AKAP7 isoforms
Authors: Redden John M. , Le Andrew V. , Singh Arpita , Federkiewicz Kyle , Smith Samantha , Dodge-Kafka Kimberly L.
Published: June 2012

The regulation of kinases by scaffolding proteins greatly contributes to the fidelity of signal transduction. In the present study, we explored an interaction between the ubiquitous enzyme PKC (protein kinase C) and the scaffolding protein AKAP7 (A-kinase-anchoring protein 7). Using protein biochemistry and surface plasmon resonance approaches, we demonstrate that both AKAP7γ and AKAP7α are capable of high-affinity interactions with multiple isoenzymes of PKC. Furthermore, this interaction is achieved via multi-site binding on both proteins. FRET (fluorescence resonance energy transfer) analysis using a PKC activity reporter suggests that anchoring of the kinase within AKAP7 complexes enhances the phosphorylation of substrate proteins. Finally, we determined using FRAP (fluorescence recovery after photobleaching) and virtual modelling that AKAP7 restricts the mobility of PKC within cells by tethering it to subcellular compartments. Collectively, the results of the present study suggests that AKAP7 could play an integral role in dictating PKC localization and function in tissues where the two proteins are co-expressed.