bluuebunny/crossref_metadata_2025 huggingface dataset:
Flower‐visitor networks only partially predict the function of pollen transport by bees
Authors: POPIC TONY J. , WARDLE GLENDA M. , DAVILA YVONNE C.
Published: March 2012

Mutualistic networks display distinct structural and organizational features such as nestedness, power‐law degree distribution and asymmetric dependencies. Attention is now focused on how these structural properties influence network function. Most plant‐pollinator networks are constructed using records of animals contacting flowers, which is based on the assumption that all visitors to flowers are pollinators; however, animals may visit flowers as nectar robbers, florivores, or to prey upon other visitors. To differentiate potential pollinator interactions from other interaction types, we examined individual bees that had visited flowers to detect if they carried pollen. Using these data, we constructed visitation and pollen‐transport networks for a spinifex‐dominated arid zone grassland. To determine how the structure of the visitation network reflects pollen transport, we compared the two networks using a null model approach to account for differences in network size. Differences in number of species, nestedness and connectance observed between the visitation and pollen‐transport networks were within expected ranges generated under the null model. The pollen‐transport network was more specialized, had lower interaction evenness, and fewer links compared to the visitation network. Almost half the number of species of the visitation network participated in the pollen‐transport network, and one‐third of unique visitation interactions resulted in pollen transport, highlighting that visitation does not always result in pollination. Floral visitor data indicate potential pollen transporters, but inferring pollination function from visitation networks needs to be performed cautiously as pollen transport resulted from both common and rare interactions, and depended on visitor identity. Although visitation and pollen‐transport networks are structurally similar, the function of all species cannot be predicted from the visitation network alone. Considering pollen transport in visitation networks is a simple first step towards determining pollinators from non‐pollinators. This is fundamental for understanding how network structure relates to network function.
Reasoning Is for Arguing: Understanding the Successes and Failures of Deliberation
Authors: Mercier Hugo , Landemore Hélène
Published: March 2012

Theoreticians of deliberative democracy have sometimes found it hard to relate to the seemingly contradictory experimental results produced by psychologists and political scientists. We suggest that this problem may be alleviated by inserting a layer of psychological theory between the empirical results and the normative political theory. In particular, we expose the argumentative theory of reasoning that makes the observed pattern of findings more coherent. According to this theory, individual reasoning mechanisms work best when used to produce and evaluate arguments during a public deliberation. It predicts that when diverse opinions are discussed, group reasoning will outperform individual reasoning. It also predicts that individuals have a strong confirmation bias. When people reason either alone or with like‐minded peers, this confirmation bias leads them to reinforce their initial attitudes, explaining individual and group polarization. We suggest that the failures of reasoning are most likely to be remedied at the collective than at the individual level.
The Association of Religiosity and Political Conservatism: The Role of Political Engagement
Authors: Malka Ariel , Lelkes Yphtach , Srivastava Sanjay , Cohen Adam B. , Miller Dale T.
Published: March 2012

Some argue that there is an organic connection between being religious and being politically conservative. We evaluate an alternative thesis that the relation between religiosity and political conservatism largely results from engagement with political discourse that indicates that these characteristics go together. In a combined sample of national survey respondents from 1996 to 2008, religiosity was associated with conservative positions on a wide range of attitudes and values among the highly politically engaged, but this association was generally weaker or nonexistent among those less engaged with politics. The specific political characteristics for which this pattern existed varied across ethno‐religious groups. These results suggest that whether religiosity translates into political conservatism depends to an important degree on level of engagement with political discourse.
A natural coumarin derivative esculetin offers neuroprotection on cerebral ischemia/reperfusion injury in mice
Authors: Wang Chen , Pei Aijie , Chen Jing , Yu Hailong , Sun Mei‐Ling , Liu Chun‐Feng , Xu Xingshun
Published: March 2012

J. Neurochem. (2012) 121, 1007–1013.

Previous studies have demonstrated that a natural coumarin compound esculetin (Esc) possesses antioxidant, anti‐tumor, and anti‐inflammation activities and rescues cultured primary neurons from NMDA toxicity. In this study, we investigated the neuroprotective effects of Esc on cerebral ischemia/reperfusion (I/R) injury in a middle cerebral artery occlusion model in mice. Esc (20 μg) was administered intracerebroventricularly at 30 min before ischemia. We found that Esc significantly reduced infarct volume and decreased neurological deficit scores after 75 min of ischemia and 24 h of reperfusion. Post‐treatment of Esc still provided neuroprotection even when Esc was administered after 4 h of reperfusion. Our data also indicated that intraperitoneal administration of Esc showed protective effects on cerebral I/R injury in a dose‐dependent manner. We further explored the protective mechanisms of Esc on cerebral I/R injury and found that Esc decreased cleaved caspase 3 level, a marker of apoptosis. Finally, our data demonstrated that Esc exerted its anti‐apoptotic activity by up‐regulating the expression of Bcl‐2 and down‐regulating the expression of Bax, two apoptosis‐related proteins. Because of its clinical use as an anticoagulant and its safety profile, Esc may have a therapeutic potential for the treatment of stroke in the future clinical trials.
Credit Booms and Lending Standards: Evidence from the Subprime Mortgage Market
Authors: DELL’ARICCIA GIOVANNI , IGAN DENIZ , LAEVEN LUC
Published: March 2012

This paper links the U.S. subprime mortgage crisis to demand‐side factors that contributed to the rapid expansion of the U.S. mortgage market. We show that denial rates were relatively lower in areas that experienced faster credit demand growth and that lenders in these high‐growth areas attached less weight to applicants’ loan‐to‐income ratios. The results are robust to controlling for supply‐side factors, including house price appreciation, mortgage securitization, and other economic fundamentals, and to several robustness tests controlling for endogeneity. The results are consistent with the notion that a relaxation of lending standards, triggered by an increased demand for loans, contributed to the boom and the ensuing crisis, together with other supply‐side explanations. These findings shed new light on the relationship between credit booms and financial instability.
The Effect of Bank Failures on Economic Activity: Evidence from U.S. States in the Early 20th Century
Authors: RAMIREZ CARLOS D. , SHIVELY PHILIP A.
Published: March 2012

This paper provides evidence documenting the existence of a “bank failure channel”—the magnifying effect of bank failures on economic distress—using state‐level quarterly time series from 1900q1 to 1929q4. We estimate a vector autoregression model of bank failures for each state. The forecast‐error variance decompositions are used to construct a categorical measure of the “bank failure channel.” We examine the influence of regulatory variables, economic conditions, and banking conditions on the degree to which bank failures propagate distress. State‐sponsored deposit insurance and minimum capital requirements are important for explaining the likelihood of having a bank failure channel.
Central Bank Communication and the Perception of Monetary Policy by Financial Market Experts
Authors: SCHMIDT SANDRA , NAUTZ DIETER
Published: March 2012

This paper investigates how financial experts perceive the monetary policy of the European Central Bank (ECB). Assuming a Taylor‐rule‐type reaction function, we use qualitative survey expectations about future interest rates, inflation, and output to discover the sources of individual interest rate forecast errors. Based on a panel random coefficient model, we show that financial experts have systematically misperceived the ECB’s interest rate rule. While perception of monetary policy regarding inflation has become more accurate since the ECB’s clarification of the monetary policy strategy in 2003, misperception regarding the ECB’s reaction to output has increased in the financial crisis.
Return on Commodity Money, Small Change Problems, and Fiat Money
Authors: KIM YOUNG SIK , LEE MANJONG
Published: March 2012

We construct a search‐theoretic model of commodity money where a penny is an indivisible silver coin that can be either melted into a silver bar yielding a positive return or used as a medium of exchange. In equilibria where the rate of return on silver is sufficiently high, small change problems arise in the form of too‐much‐trade inefficiency because of a too‐high value of a penny and no‐trade inefficiency because of a shortage of coins in circulation. In the fiat money system, however, trades are not affected at all by the rate of return on silver and the value of a penny is determined by its medium‐of‐exchange role without incurring the loss in efficiency due to small change problems.
Rollover Risk and Credit Risk
Authors: HE ZHIGUO , XIONG WEI
Published: March 2012

Our model shows that deterioration in debt market liquidity leads to an increase in not only the liquidity premium of corporate bonds but also credit risk. The latter effect originates from firms' debt rollover. When liquidity deterioration causes a firm to suffer losses in rolling over its maturing debt, equity holders bear the losses while maturing debt holders are paid in full. This conflict leads the firm to default at a higher fundamental threshold. Our model demonstrates an intricate interaction between the liquidity premium and default premium and highlights the role of short‐term debt in exacerbating rollover risk.
The Secondary Market for Hedge Funds and the Closed Hedge Fund Premium
Authors: RAMADORAI TARUN
Published: March 2012

Rational theories of the closed‐end fund premium puzzle highlight fund share and asset illiquidity, managerial ability, and fees as important determinants of the premium. Several of these attributes are difficult to measure for mutual funds, and easier to measure for hedge funds. This paper employs new data from a secondary market for hedge funds, discovers a closed‐hedge fund premium that is highly correlated with the closed‐end mutual fund premium, and shows that the closed‐hedge fund premium is well explained by variables suggested by rational theories. Sentiment‐based explanations do not find support in the data.
Postmortem Vitreous Beta‐Hydroxybutyrate: Interpretation in a Forensic Setting*
Authors: Heninger Michael
Published: March 2012

Abstract:  Vitreous beta‐hydroxybutyrate (BHB) was retrospectively analyzed in 1795 forensic cases using the Pointe Scientific method. Comparison of vitreous BHB with vitreous glucose in 1781 of the cases showed moderately good correlation r = 0.731. Comparison with blood alcohol levels in 1561 of the cases showed no correlation r = −0.053. Vitreous BHB was a marker of diabetic ketoacidosis when above 6.0 mM with a vitreous glucose over 200 mg/dL. It was an indicator (>50%) for alcoholic ketoacidosis when above 6.0 mM with a vitreous glucose below 200 mg/dL. Recommendations for interpretation of vitreous BHB: <0.4 mM normal; 0.41–1.2 mM slightly elevated, rarely (<1%) of concern; 1.21–2.0 mM moderately elevated, less rarely (2.5%) of concern; 2.01–6.0 mM significantly elevated, frequently of concern (12–48%); >6.0 mM usually (100% in this study) indicated life‐threatening conditions. Vitreous BHB was helpful evaluating cases with ketogenic conditions, especially diabetes and alcoholism.
Expression and effects of glial cell line‐derived neurotrophic factor on periodontal ligament cells
Authors: Yamamoto Naohide , Maeda Hidefumi , Tomokiyo Atsushi , Fujii Shinsuke , Wada Naohisa , Monnouchi Satoshi , Kono Kiyomi , Koori Katsuaki , Teramatsu Yoko , Akamine Akifumi
Published: March 2012

Aim

To investigate Glial cell line‐derived neurotrophic factor (GDNF) expression in normal and wounded rat periodontal ligament (PDL) and the effects of GDNF on human PDL cells (HPDLCs) migration and extracellular matrix expression in HPDLCs.

Material and Methods

The expression of GDNF and GDNF receptors was examined by immunocyto/histochemical analyses. Gene expression in HPDLCs treated with GDNF, interleukin‐1 beta (IL‐1β), or tumour necrosis factor‐alpha (TNF‐α) was quantified by quantitative RT‐PCR (qRT‐PCR). In addition, we examined the migratory effect of GDNF on HPDLCs.

Results

GDNF was expressed in normal rat PDL and cultured HPDLCs. HPDLCs also expressed GDNF receptors. In wounded rat PDL, GDNF expression was up‐regulated. QRT‐PCR analysis revealed that IL‐1β and TNF‐α significantly increased the expression of GDNF in HPDLCs. Furthermore, GDNF induced migration of HPDLCs, which was blocked by pre‐treatment with the peptide including Arg‐Gly‐Asp (RGD) sequence, or neutralizing antibodies against integrin αVβ3 or GDNF. Also, GDNF up‐regulated expression of bone sialoprotein (BSP) and fibronectin in HPDLCs.

Conclusions

GDNF expression is increased in rat wounded PDL tissue and HPDLCs treated with pro‐inflammatory cytokines. GDNF enhances the expression of BSP and fibronectin, and migration in an RGD‐dependent manner via the integrin αVβ3. These findings suggest that GDNF may contribute to wound healing in PDL tissue.
Review of ‘The Plant List, a working list of all plant species’
Authors: Kalwij Jesse M.
Published: March 2012

The Plant List (http://www.theplantlist.org/) is an on‐line database of plant names that aims to be comprehensive for all described plant species. Version 1 of The Plant List includes 1 040 426 plant name records, of which 298 900 are accepted names. The Plant List is the product of a consortium of the Royal Botanic Gardens, Kew, and the Missouri Botanical Garden. In this review, I evaluate the use of this plant taxonomic database for plant ecologists. The web interface of The Plant List allows a quick search for species names and corresponding synonyms. Moreover, users are able to download search or browse results to compile a customized checklist of plant names. The combination of a straightforward web design and the possibility to download search results provides a valuable resource of plant nomenclature information for a wide range of plant ecologists.
Looking for Better Health in All the Wrong Places: The Road to “Equality” Hits a Dead End
Authors: Miller Tom
Published: March 2012

I was initially assigned the working title, “Pursuing Equality in Health Care for the Elderly Is Futile.” I prefer to think of that particular dead end of health policy as one of listening to the wrong music for too long. Hence, this article reprises and revises the title song of the early 1980s movie, Urban Cowboy, but with Johnny Lee’s original lyrics adapted as “Looking for better health [rather than either ‘love’ or ‘love of equality’] in all the wrong places.” The better goal is to achieve more progress in improving health for more people, including (but not limited to) the elderly. It need not be as futile as the pursuit of the elusive abstraction of “equality” for all — but only if we first move away from a path-dependent approach of recent times that remains too narrowly focused on statistical disparities in health care services received by particular groups.
Physicians Should “Assist in Suicide” When it is Appropriate
Authors: Quill Timothy E.
Published: March 2012

In my career as a primary care physician and as a palliative care consultant, I have assisted many patients to die with their full consent. None of them wanted to die, and all would have chosen other paths had their disease not been so severe and irreversible. To a person, none of these patients thought of themselves as “suicidal,” and they would have found that label preposterous and demeaning. In fact, the kind of personal disintegration that the label implies is just what is trying to be prevented by those choosing this possibility. So on behalf of patients who have chosen this option, I reject the title of this debate as it unnecessarily tars the discussion with the suggestion of mental illness. In my primary care practice, I have also met many patients who were “suicidal” in the mental health sense of the word, and rest assured I have assisted none of them to die. In fact, I have at times had them involuntarily hospitalized to prevent them from carrying out their wishes.
Public Health Ethics Theory: Review and Path to Convergence
Authors: Lee Lisa M.
Published: March 2012

For over 100 years, the field of contemporary public health has existed to improve the health of communities and populations. As public health practitioners conduct their work – be it focused on preventing transmission of infectious diseases, or prevention of injury, or prevention of and cures for chronic conditions – ethical dimensions arise. Borrowing heavily from the ethical tools developed for research ethics and bioethics, the nascent field of public health ethics soon began to feel the limits of the clinical model and began creating different frameworks to guide its ethical challenges. Several public health ethics frameworks have been introduced since the late 1990s, ranging from extensions of principle-based models to human rights and social justice perspectives to those based on political philosophy. None has coalesced as the framework of choice in the discipline of public health. This paper examines several of the most-known frameworks of public health ethics for their common theoretical underpinnings and values, and suggests next steps toward the formulation of a single framework.
The Impact of Defense Expenses in Medical Malpractice Claims
Authors: Carroll Aaron E. , Parikh Parul Divya , Buddenbaum Jennifer L.
Published: March 2012

Whenever health care reform is debated, the state of the medical professional liability (MPL) system (i.e., medical malpractice system) in the United States re-emerges as an issue of importance. What exactly is broken with the MPL system and what the implications are is a point of contention among different stakeholder groups. Recent data demonstrate that medical liability premiums have been improving in recent years and the majority of premiums remained flat in 2010. General agreement still exists, however, that medical professional liability insurance premiums have become unaffordable for many physicians, and coverage has become less available, especially for certain medical specialties and in specific areas of the country.

Multiple factors go into the determination of medical professional liability insurance premiums including return on investments, reinsurance costs, claims frequency, average amount paid out on malpractice claims, defense expenses, and administrative costs such as underwriting expense.
Spatial and temporal effects on seed dispersal and seed predation of Musa acuminata in southern Yunnan, China
Authors: MENG Lingzeng , GAO Xiuxia , CHEN Jin , MARTIN Konrad
Published: March 2012

Wild bananas are abundant in tropical areas and many ecologists have observed that the succession process is quicker following increased disturbance. This study was conducted to analyze animal‐seed interactions and their effects on the seed fate of a wild banana species (Musa acuminata) in tropical southern Yunnan (China) through experiments considering spatial (site and habitat) and temporal (seasons) variation. The largest proportion of fruits (81%) was removed by frugivorous seed dispersers, especially by bats at nighttime. Only 13% of the fruits were removed by climbing seed predators (different species of rats). In the exclosure treatment, rodents accounted for a significantly higher total artificially exposed seed removal number than ants, but with spatial and temporal differences. The highest seed predation rate by rodents (70%) was found in forest with wild banana stands, corresponding with the highest rodent diversity (species numbers and abundance) among the habitat types. In contrast, the seed removal number by ants (57%) was highest in the open land habitats, but there was no close correlation with ant diversity. Seed removal numbers by ants were significantly higher in the dry compared to the rainy season, but rodent activity showed no differences between seasons. The overall results suggest that the largest proportion of seeds produced by wild banana are primarily dispersed by bats. Primary seed dispersal by bats at nighttime is essential for wild banana seeds to escape seed predation.
Relative abundance of American badger (Taxidea taxus) and red fox (Vulpes vulpes) in landscapes with high and low rodenticide poisoning levels
Authors: PROULX Gilbert , MacKENZIE Neil
Published: March 2012

Over the past decade, extensive poisoning campaigns have been conducted in southern Saskatchewan to control Richardson's ground squirrelSpermophilus richardsonii(Sabine, 1822) populations. Such campaigns might impact on predator abundance by decreasing prey levels, and also through secondary poisoning. Using spotlighting, we investigated the relative abundance of American badgersTaxidea taxus(Schreber, 1777) and red foxVulpes vulpes(Linnaeus, 1758) in 2 study areas with road access and crops, but with different levels of poisoning. In the study area with relatively low poisoning (19.6% of the area traversed by roads), there were 2.2 times more American badgers per km of road and 6.4 times more red foxes per km than in the study area with high poisoning (89.7% of the area). It is recommended that an Integrated Pest Management program be developed to conserve natural predators across landscapes.
Yersinia pestis: examining wildlife plague surveillance in China and the USA
Authors: BEVINS Sarah N. , BAROCH John A. , NOLTE Dale L. , ZHANG Min , HE Hongxuan
Published: March 2012

Plague is a zoonotic disease caused by the bacterium Yersinia pestis Lehmann and Neumann, 1896. Although it is essentially a disease of rodents, plague can also be transmitted to people. Historically, plague has caused massive morbidity and mortality events in human populations, and has recently been classified as a reemerging disease in many parts of the world. This public health threat has led many countries to set up wild and domestic animal surveillance programs in an attempt to monitor plague activity that could potentially spill over into human populations. Both China and the USA have plague surveillance programs in place, but the disease dynamics differ in each country. We present data on plague seroprevalence in wildlife and review different approaches for plague surveillance in the 2 countries. The need to better comprehend plague dynamics, combined with the fact that there are still several thousand human plague cases per year, make well‐designed wildlife surveillance programs a critical part of both understanding plague risks to humans and preventing disease outbreaks in the future.
Three cases of acute or fulminant hepatitis E caused by ingestion of pork meat and entrails in Hokkaido, Japan: Zoonotic food‐borne transmission of hepatitis E virus and public health concerns
Authors: Miyashita Kencho , Kang Jong‐Hon , Saga Akiyoshi , Takahashi Kazuaki , Shimamura Tsuyoshi , Yasumoto Atsushi , Fukushima Hiraku , Sogabe Susumu , Konishi Kouhei , Uchida Takumi , Fujinaga Akira , Matsui Takeshi , Sakurai Yasuo , Tsuji Kunihiko , Maguchi Hiroyuki , Taniguchi Masahiko , Abe Natsumi , Fazle Akbar Sheikh Mohammad , Arai Masahiro , Mishiro Shunji
Published: March 2012

Aim:  In developed countries including Japan, the transmission route of indigenous hepatitis E virus (HEV) infection is obscure. Accordingly, public health implications of indigenous HEV infection have not been well addressed. The aim of this study was to clarify the route of transmission of a small outbreak of acute hepatitis E and assess the public health implications of indigenous zoonotic HEV transmission.

Methods:  Three patients with non‐A, B and C acute hepatitis, two of whom presented in a critical condition, were assessed for HEV infection using polymerase chain reaction and their route of infection; the genome sequences of the infecting HEV were also analyzed. A phylogenetic tree based on the full, or near full, HEV RNA sequences were constructed by neighbor‐joining method.

Results:  All three patients ingested grilled pork meat and entrails at the same barbecue restaurant in Abashiri, Hokkaido, Japan. When comparing partial to entire, or nearly entire, nucleotide sequences of HEV detected in these patients, they were 99.9–100% identical to each other. These genotype 4 isolates had great resemblance to the genome sequences of the isolates from the mini‐outbreak in 2004 in Kitami, a city adjacent to Abashiri. These Kitami/Abashiri strains were segregated into a single cluster on the phylogenetic tree of HEV genotype 4 indigenous to Japan.

Conclusion:  Indigenous HEV transmission via a zoonotic food‐borne route has been demonstrated in Kitami and Abashiri via pork meat and entrails contaminated with virulent HEV strains. Because a similar outbreak can recur in the future, infection sources and distribution routes should be clarified rapidly for public health.
Collision of Two Mass Baton With Massive External Surfaces
Authors: Tavakoli Ali , Gharib Mohamed , Hurmuzlu Yildirim
Published: March 2012

This paper presents the solution of the impact problem for a sliding/bouncing baton on flat and inclined planes subject to surface friction. The baton is assumed to have unilaterally constrained motion, which means one end slides on the ground while the other end collides with the ground. We use the impulse momentum approach and incorporate the impulse correlation ratio (ICR) hypothesis to solve the ground impact problem when the system has unilaterally constrained dynamics. Parametric investigations were carried out to examine the effect of the baton’s length and the inclined surface slope angle on the impulse correlation ratio. Numerical simulation and experiments were carried out to validate the model.
Determination of Isospectral Nonuniform Rotating Beams
Authors: Kambampati Sandilya , Ganguli Ranjan , Mani V.
Published: March 2012

In this paper we look for nonuniform rotating beams that are isospectral to a given uniform nonrotating beam. A rotating nonuniform beam is isospectral to the given uniform nonrotating beam if both the beams have the same spectral properties, i.e., both the beams have the same set of natural frequencies under a given boundary condition. The Barcilon-Gottlieb type transformation is proposed that converts the governing equation of a rotating beam to that of a uniform nonrotating beam. We show that there exist rotating beams isospectral to a given uniform nonrotating beam under some special conditions. The boundary conditions we consider are clamped-free and hinged-free with an elastic hinge spring. An upper bound on the rotation speed for which isospectral beams exist is proposed. The mass and stiffness distributions for these nonuniform rotating beams which are isospectral to the given uniform nonrotating beam are obtained. We use these mass and stiffness distributions in a finite element analysis to show that the obtained beams are isospectral to the given uniform nonrotating beam. A numerical example of a beam having a rectangular cross section is presented to show the application of our analysis.
A Combined Finite Element-Multiple Criteria Optimization Approach for Materials Selection of Gas Turbine Components
Authors: Shanian A. , Milani A. S. , Vermaak N. , Bertoldi K. , Scarinci T. , Gerendas M.
Published: March 2012

The design of critical components for aerospace applications involves a number of conflicting functional requirements: reducing fuel consumption, cost, and weight, while enhancing performance, operability and robustness. As several materials systems and concepts remain competitive, a new approach that couples finite element analysis (FEA) and established multicriteria optimization protocols is developed in this paper. To demonstrate the approach, a prototypical materials selection problem for gas turbine combustor liners is chosen. A set of high temperature materials systems consisting of superalloys and thermal barrier coatings is considered as candidates. A thermo-mechanical FEA model of the combustor liner is used to numerically predict the response of each material system candidate. The performance of each case is then characterized by considering the material cost, manufacturability, oxidation resistance, damping behavior, thermomechanical properties, and the FEA postprocessed parameters relating to fatigue and creep. Using the obtained performance values as design criteria, an ELECTRE multiple attribute decision-making (MADM) model is employed to rank and classify the alternatives. The optimization model is enhanced by incorporating the relative importance (weighting factors) of the selection criteria, which is determined by multiple designers via a group decision-making process.
Magnetohydrodynamics Free Convection Flow of a Radiating and Chemically Reacting Fluid Past an Impulsively Moving Plate With Ramped Wall Temperature
Authors: Das Kalidas
Published: March 2012

In the present study, the effects of radiation and chemical reaction on unsteady free convection flow and mass transfer of a viscous, electrically conducting incompressible fluid near an impulsively moving vertical flat plate with ramped wall temperature is studied. The primary purpose of this study is to characterize the effects of ramped wall temperature, radiation parameter, chemical reaction parameter, Schmidt number etc., on the flow properties. Exact solutions of the present problem are obtained in closed form by Laplace transform technique. The variations in fluid velocity, temperature and concentration are shown graphically whereas numerical values of skin friction, rate of heat and mass transfer are presented in tabular form to observe the effects of various parameters.
Control of Sleep by Cyclin A and Its Regulator
Authors: Rogulja Dragana , Young Michael W.
Published: March 2012

Sleeping Around the Clock

Fruit flies do not sleep all night like humans, but they do manage to spend about half of their day in bouts of inactivity that have similarity to sleep in other species.
Rogulja and Young
(p.
1617
) searched for genes in neurons whose products regulated sleep. Depletion of the protein regulator of cyclin A1 (Rca1) caused the flies to be slow to go to sleep and to get less total sleep in a day because their sleep episodes were shorter. The mechanism by which Rca1 influences sleep is not yet clear. It appears not to disrupt circadian rhythms. However, the neurons that express Rca1 in the fly brain are located near the neurons that make up the circadian clock, potentially allowing for coordination of circadian behavior with sleep regulation.
RETRACTED: A Shorter
146
Sm Half-Life Measured and Implications for
146
Sm-
142
Nd Chronology in the Solar System
Authors: Kinoshita N. , Paul M. , Kashiv Y. , Collon P. , Deibel C. M. , DiGiovine B. , Greene J. P. , Henderson D. J. , Jiang C. L. , Marley S. T. , Nakanishi T. , Pardo R. C. , Rehm K. E. , Robertson D. , Scott R. , Schmitt C. , Tang X. D. , Vondrasek R. , Yokoyama A.
Published: March 2012

A New Lease on Half-Life

Radiometric dating relies on measuring the abundance of long-lived radionuclides relative to the abundance of their radiogenic decay products—a process determined by the original radionuclide's half-life. For primordial radionuclides that decay slowly, such as
146
Sm decaying to
142
Nd, this method provides the timing of some of the earliest processes in solar system history. Using accelerator mass spectrometry,

Kinoshita
et al.

(p.
1614
) provide a revised estimate for the
146
Sm half-life of ∼68.7 million years, which is 30% shorter than the previously accepted value. This shorter half-life suggests that reductions need to be made in the estimated ages for differentiation of Earth's mantle and the solidification of the Moon's magma ocean and for other more recent processes.
Adapting to Osmotic Stress and the Process of Science
Authors: Gasper Brittany J. , Minchella Dennis J. , Weaver Gabriela C. , Csonka Laszlo N. , Gardner Stephanie M.
Published: March 2012

“Genetic Analysis of Adaptation to Osmotic Stress in
Salmonella
,” the IBI Prize–winning module, uses mutant isolation and DNA sequencing to engage students in bacterial genetics and evolution.
Disentangling the Electronic and Phononic Glue in a High-
T

c

Superconductor
Authors: Dal Conte S. , Giannetti C. , Coslovich G. , Cilento F. , Bossini D. , Abebaw T. , Banfi F. , Ferrini G. , Eisaki H. , Greven M. , Damascelli A. , van der Marel D. , Parmigiani F.
Published: March 2012

Electrons Beat Phonons

The phenomenon of superconductivity, in which a material suddenly (below a certain transition temperature

T
c

) becomes a perfect conductor with zero electrical resistance, can be roughly explained in terms of Bose-Einstein condensation of pairs of electrons. In conventional superconductors, the formation of these so-called Cooper pairs is mediated by lattice deformations (phonons), but this mechanism is insufficient to explain the high

T
c

of cuprate superconductors. Other mechanisms, such as magnetic fluctuations, have been proposed which originate with the electrons themselves rather than the lattice.

Dal Conte
et al.

(p.
1600
) used time-resolved optical spectroscopy of an optimally doped cuprate to show that the temporal evolution of the reflectivity is consistent with the electronic contribution being dominant and is able to account for the high

T
c

by itself.
Segregation and Wiring in the Brain
Authors: Zilles Karl , Amunts Katrin
Published: March 2012

Are there unifying principles behind the structural complexity of the cerebral cortex?
Engage to Excel
Authors: Gates S. James , Mirkin Chad
Published: March 2012

In 2010, we and our colleagues on the President's Council of Advisors on Science and Technology (PCAST) released a report entitled
Prepare and Inspire: K-12 Education in Science, Technology, Engineering and Math (STEM) Education for America's Future
. This important report advocates preparing all students to use STEM in their personal and professional lives and inspiring them to learn STEM subjects and pursue STEM careers. But in the United States, over 60% of students who enter college intending to major in a STEM field fail to graduate with a STEM degree. Because economic analyses forecast that the United States will need 1 million more STEM graduates over the next decade than will be produced by our current modes of education,
*
reducing this dropout rate is the focus of a second report we released last month, called
Engage to Excel: Producing One Million Additional College Graduates with Degrees in Science, Technology, Engineering, and Mathematics
.
†
The Epstein-Barr Virus BcRF1 Gene Product Is a TBP-Like Protein with an Essential Role in Late Gene Expression
Authors: Gruffat Henri , Kadjouf Faouzi , Mariamé Bernard , Manet Evelyne
Published: March 2012

That the expression of late genes is coupled to viral genome replication is well established for all herpesviruses, but the exact mechanisms of their regulation, especially by viral proteins, are poorly understood. Here, we report the identification of the Epstein-Barr virus (EBV) early protein BcRF1 as a viral factor crucial for the activation of late gene transcription following viral DNA replication during the productive cycle. In order to study the function of the BcRF1 protein, we constructed a recombinant EBV lacking this gene. In HEK293 cells, this recombinant virus underwent normal DNA replication during the productive cycle but failed to express high levels of late gene transcripts or proteins, resulting in a nonproductive infection. Interestingly, a TATT motif is present in the promoter of most EBV late genes, at the position of the TATA box. We show here that BcRF1 forms a complex with the TATT motif and that this interaction is required for activation of late viral gene expression. Moreover, our results suggest that BcRF1 acts via interaction with other viral proteins.
A Nonfucosylated Variant of the anti-HIV-1 Monoclonal Antibody b12 Has Enhanced FcγRIIIa-Mediated Antiviral Activity
In Vitro
but Does Not Improve Protection against Mucosal SHIV Challenge in Macaques
Authors: Moldt Brian , Shibata-Koyama Mami , Rakasz Eva G. , Schultz Niccole , Kanda Yutaka , Dunlop D. Cameron , Finstad Samantha L. , Jin Chenggang , Landucci Gary , Alpert Michael D. , Dugast Anne-Sophie , Parren Paul W. H. I. , Nimmerjahn Falk , Evans David T. , Alter Galit , Forthal Donald N. , Schmitz Jörn E. , Iida Shigeru , Poignard Pascal , Watkins David I. , Hessell Ann J. , Burton Dennis R.
Published: March 2012

Eliciting neutralizing antibodies is thought to be a key activity of a vaccine against human immunodeficiency virus (HIV). However, a number of studies have suggested that in addition to neutralization, interaction of IgG with Fc gamma receptors (FcγR) may play an important role in antibody-mediated protection. We have previously obtained evidence that the protective activity of the broadly neutralizing human IgG1 anti-HIV monoclonal antibody (MAb) b12 in macaques is diminished in the absence of FcγR binding capacity. To investigate antibody-dependent cellular cytotoxicity (ADCC) as a contributor to FcγR-associated protection, we developed a nonfucosylated variant of b12 (NFb12). We showed that, compared to fully fucosylated (referred to as wild-type in the text) b12, NFb12 had higher affinity for human and rhesus macaque FcγRIIIa and was more efficient in inhibiting viral replication and more effective in killing HIV-infected cells in an ADCC assay. Despite these more potent
in vitro
antiviral activities, NFb12 did not enhance protection
in vivo
against repeated low-dose vaginal challenge in the simian-human immunodeficiency virus (SHIV)/macaque model compared to wild-type b12. No difference in protection, viral load, or infection susceptibility was observed between animals given NFb12 and those given fully fucosylated b12, indicating that FcγR-mediated activities distinct from FcγRIIIa-mediated ADCC may be important in the observed protection against SHIV challenge.
Time trends in STEMI—improved treatment and outcome but still a gender gap: a prospective observational cohort study from the SWEDEHEART register
Authors: Lawesson Sofia Sederholm , Alfredsson Joakim , Fredrikson Mats , Swahn Eva
Published: March 2012

Objective

In ST elevation myocardial infarction women received less evidence-based medicine and had worse outcome during the fibrinolytic era. With the shift to primary percutaneous coronary intervention (pPCI) as preferred reperfusion strategy, the authors aimed to investigate whether these gender differences has diminished.

Design, setting and participants

Cohort study including consecutive ST elevation myocardial infarction patients registered 1998–2000 (n=15 697) and 2004–2006 (n=14 380) in the Register of Information and Knowledge about Swedish Heart Intensive care Admissions.

Outcome measures

1. Use of evidence-based medicine such as reperfusion therapy (pPCI or fibrinolysis) and evidence-based drugs at discharge. 2. Inhospital and 1-year mortality.

Results

Of those who got reperfusion therapy, pPCI was the choice in 9% in the early period compared with 68% in the late period. In the early period, reperfusion therapy was given to 63% of women versus 71% of men, p<0.001. Corresponding figures in the late period were 64% vs 75%, p<0.001. After multivariable adjustments, the ORs (women vs men) were 0.86 (95% CI 0.78 to 0.94) in the early and 0.80 (95% CI 0.73 to 0.89) in the late period. As regards evidence-based secondary preventive drugs at discharge in hospital survivors (platelet inhibitors, statins, ACE inhibitors/angiotensin receptor blockers and β-blockers), there were small gender differences in the early period. In the late period, women had 14%–25% less chance of receiving these drugs, OR 0.75 (95% CI 0.68 to 0.81) through 0.86 (95% CI 0.73 to 1.00). In both periods, multivariable-adjusted inhospital mortality was higher in women, OR 1.18 (95% CI 1.02 to 1.36) and 1.21 (1.00 to 1.46). One-year mortality was gender equal, HR 0.95 (95% CI 0.87 to 1.05) and 0.96 (0.86 to 1.08), after adding evidence-based medicine to the multivariable adjustments.

Conclusion

In spite of an intense gender debate, focus on guideline adherence and the change in reperfusion strategy, the last decade gender differences in use of reperfusion therapy and evidence-based therapy at discharge did not decline during the study period, rather the opposite. Moreover, higher mortality in women persisted.
Sex differences in lipid metabolism and metabolic disease risk
Authors: Sugiyama Michael G. , Agellon Luis B.
Published: March 2012

The ability of nutrients to regulate specific metabolic pathways is often overshadowed by their role in basic sustenance. Consequently, the mechanisms whereby these nutrients protect against or promote a variety of acquired metabolic syndromes remains poorly understood. Premenopausal women are generally protected from the adverse effects of obesity despite having a greater proportion of body fat than men. Menopause is often associated with a transformation in body fat morphology and a gradual increase in the susceptibility to metabolic complications, eventually reaching the point where women and men are at equal risk. These phenomena are not explained solely by changes in food preference or nutrient intake suggesting an important role for the sex hormones in regulating the metabolic fate of nutrients and protecting against metabolic disease pathophysiology. Here, we discuss how differences in the acquisition, trafficking, and subceullular metabolism of fats and other lipid soluble nutrients in major organ systems can create overt sex-specific phenotypes, modulate metabolic disease risk, and contribute to the rise in obesity in the modern sedentary climate. Identifying the molecular mechanisms underpinning sex differences in fat metabolism requires the unravelling of the interactions among sex chromosome effects, the hormonal milieu, and diet composition. Understanding the mechanisms that give rise to sex differences in metabolism will help to rationalize treatment strategies for the management of sex-specific metabolic disease risk factors.
Sex-dependent differences in rat hepatic lipid accumulation and insulin sensitivity in response to diet-induced obesity
Authors: Nadal-Casellas Antònia , Proenza Ana Maria , Lladó Isabel , Gianotti Magdalena
Published: March 2012

Ectopic deposition of lipids in liver and other extrahepatic tissues alters their function and occurs once adipose tissue fat storage capacity is exceeded. We investigated sexual dimorphism in the effects of dietary obesity on the liver insulin signaling pathway, as well as its connection to differences in hepatic fat accumulation. Ten-week-old Wistar rats of both sexes were fed a standard diet or a high-fat diet for 26 weeks. Insulin, adipokine levels, and glucose tolerance were measured. Lipid content, PPARα mRNA expression and protein levels of insulin receptor subunit β (IRβ), IR substrate 2 (IRS-2), Ser/Thr kinase A (Akt), and pyruvate dehydrogenase kinase isozyme 4 (PDK4) were measured in liver. In control rats, serum parameters and hepatic levels of IRβ, IRS-2, and Akt proteins pointed to a profile of better insulin sensitivity in females. In response to dietary treatment, female rats exhibited a greater increase in body mass and adiposity and lower liver fat accumulation than males, but maintained better glucose tolerance. The reduced insulin signaling capacity in the liver of obese female rats seems to prevent lipid accumulation and probably lipotoxicity-associated hepatic disorders.
Breast cancer cells adapt to metabolic stress by increasing ethanolamine phospholipid synthesis and CTP:ethanolaminephosphate cytidylyltransferase-Pcyt2 activity
Authors: Zhu Lin , Bakovic Marica
Published: March 2012

The significance of phosphatidylethanolamine (PE) in breast cancer cell metabolism was investigated under stress conditions caused by serum deficiency. Serum deficient MCF-7 cells adapt to stress conditions by increasing synthesis and content of PE and diacylglycerol (DAG). The biosynthesis of PE from DAG and ethanolamine was regulated at the level of formation of CDP-ethanolamine, the metabolic step catalyzed by Pcyt2. The catalytic activity of Pcyt2 was elevated 2–3-fold, yet the enzyme remained rate-limiting in serum-deficient cells. Contributions to the elevated Pcyt2 activity included transcriptional and translational components. The mRNA levels of two splice variants, Pcyt2α and Pcyt2β, were 1.5–3-fold higher in deficient cells. The total amounts of Pcyt2 and Pcyt2α proteins were similarly elevated 1.5–2.5-fold. In vivo [γ32Pi] radiolabeling revealed that Pcyt2 was additionally regulated by phosphorylation. Under unfavorable metabolic conditions, both endogenous and His/Myc-tagged Pcyt2 were increasingly phosphorylated at Ser residues. The results established that elevated DAG formation and the increased activity of the rate-regulatory enzyme Pcyt2 were critical modulators of the PE Kennedy pathway, and total PE content in serum deprived breast cancer cells. Therefore, as an essential gene sensitive to nutritional microenvironment, Pcyt2 could represent a legitimate target in novel metabolic strategies for cancer.
HSPA2 overexpression protects V79 fibroblasts against bortezomib-induced apoptosis
Authors: Filipczak Piotr Teodor , Piglowski Wojciech , Glowala-Kosinska Magdalena , Krawczyk Zdzislaw , Scieglinska Dorota
Published: March 2012

Human HSPA2 is a member of the HSPA (HSP70) family of heat-shock proteins, encoded by the gene originally described as testis-specific. Recently, it has been reported that HSPA2 can be also expressed in human somatic tissues in a cell-type specific manner. The aim of the present study was to find out whether HSPA2 can increase the resistance of somatic cells to the toxic effect of heat shock, proteasome inhibitors, and several anticancer cytostatics. We used a Chinese hamster fibroblast V79 cell line because these cells do not express the HSPA2 and cytoprotective HSPA1 proteins under normal culture conditions and show limited ability to express HSPA1 in response to heat shock and proteasome inhibitors. We established, by retroviral gene transfer, a stable V79/HSPA2 cell line, which constitutively overexpressed HSPA2 protein. The major observation of our study was that HSPA2 increased long-term survival of cells subjected to heat shock and proteasome inhibitors. We found, that HSPA2 confers resistance to bortezomib-induced apoptosis. Thus, we showed for the first time that in somatic cells HSPA2 can be a part of a system protecting cells against cytotoxic stimuli inducing proteotoxic stress.