bluuebunny/crossref_metadata_2025 huggingface dataset:
History and the Social Sciences: some Reflections on the Re-Integration of Social Science
Authors: Francis E. K.
Published: August 2009

About twenty-five years ago, the fields and methods of the different academic disciplines concerned with the study of man and his works, and the relations between these disciplines, were a favorite theme of discussion. At that time, the so-called social sciences were experiencing a spectacular expansion in scope simultaneously gaining depth through the constant refinement of their methods. Increasing division of labor in research focused attention on marginal areas, giving rise thereby to several new specialties which threatened to encroach upon already established disciplines. These sometimes heated discussions were, as a whole, a healthy sign of the progress made by the new science of man, which then went through the growing pains of its adolescence. They also meant a staking out of claims between professional groups, a search for new labels and standards, and a reshuffling and re-naming of college courses and text books. This process of reorientation resulted in the organizational structure within which both research and teaching in the American institutions of higher learning have been carried out ever since. Once the demarcation lines had been drawn, however, interest in problems pertaining to the logic of science decreased; and the scholars in the different fields settled down to putting in practice what had now been defined as their proper task.
In Heidegger's Shadow: Hannah Arendt's Phenomenological Humanism
Authors: Hinchman Lewis P. , Hinchman Sandra K.
Published: August 2009

Hannah Arendt's political theory gains in clarity and resonance when it is placed in the context of German phenomenology and Existenz philosophy. In this essay, the authors examine the points of contact (on the level of ideas rather than personal ties) between Arendt and Martin Heidegger. The argument holds that Arendt followed Heidegger in grafting traditional humanism onto an untraditional, self-consciously antimetaphysical body of thought. Yet almost from the beginning, she struck out in a direction peculiarly her own, seeking to escape a certain contemplative aloofness and remoteness from public affairs which she sensed in Heidegger's fundamental ontology. Against Heidegger, Arendt tried to show that the core values of human rights and dignity cannot be sustained unless one explicitly recognizes the “plurality” of human life and the importance of the public realm in revealing who we are as individuals.
Pascal on Justice, Force, and Law
Authors: Beitzinger A. J.
Published: August 2009

This paper focuses on Pascal's controversial pronouncements on justice, force and law. It proceeds, in light of a preliminary examination of historical context, questions of textual interpretation, and Pascal's method and study of man, to show in Pascal's thought a theory of law which (a) rejects rationalist and naturalist explanations, (b) incorporates positivism and by implication what is today called “historicism,” and (c) transcends both positivism and historicism dialectically in a Christocentric biblical view of cosmic order.
The Sociology of Taxation
Authors: Mann Fritz Karl
Published: August 2009

Modern financial history records two fundamental changes in the concept of taxation. While, from the 16th to the 18th century, tax collection was considered as an expedient in times of emergency and even an abuse which as soon as possible should be replaced by income derived from public property, particularly domains, and by voluntary contributions, common opinion has gradually acquiesced in its permanent character. Current taxation is the inseparable twin of the modern State. This is as true for socialist as for capitalist countries. It is significant that even Soviet Russia, in spite of her vigorous collectivization, had to admit that the government could be more easily financed by current compulsory contributions than by the yield of public enterprises. After a brief diversion into the Utopian tax-free stage during the years 1920 and 1921, she regretfully returned, under the auspices of the New Economic Policy (NEP), to a broad scheme of direct and indirect taxation. Moreover, the recent suggestion of a follower of Mr. Keynes that taxation be stripped of its traditional function since the raising of revenue “can be brought about so much more easily by printing the money.” seems not to have made any deep impression on public opinion. Except for times of emergency and wars, governments are condemned for borrowing a large proportion of their needs.
Approaches to the Comparative Analysis of Political Leadership
Authors: Edinger Lewis J.
Published: August 2009

This article opens with some general observations on outstanding features of the current literature on political leadership, especially in the United States. It then deals briefly with conceptual problems, level of analysis issues, and counter-factual questions. This is followed by a consideration of major modes of analysis for the comparative study of political leadership. The concluding section points up the principal ways to making comparative generalization about the sources and nature of leadership in politics.
Lot as a Democratic Device of Selection
Authors: Mulgan Richard G.
Published: August 2009

Lot is a possible alternative to election as a democratic means of selection. The prime historical instance of its political use is classical Athens. Lot was an important expression of the Athenian democrats' commitment to equality, more egalitarian than election which assumed equality of opportunity rather than desert. Lot also had certain important political effects, such as reducing factionalism and maintaining the authority of the assembly. It helped to make the Council and the courts representative cross sections of the assembly. Election, however, was preferable when important decisions were to be entrusted to only a few people. In modern democratic societies, lot is not uncommon as a distributive device but is rarely used for selecting political officials. Election remains more democratically efficient for large polities, but lot could be seriously considered in communities which approach the small size and intimacy of the Greek city-states.
On the Epistolary Dialogue Between Leo Strauss and Eric Voegelin
Authors: Pangle Thomas L.
Published: August 2009

The philosophic correspondence between Leo Strauss and Eric Voegelin, stretching over thirty years, sheds some helpful light on each of the thinkers’ philosophic positions. To be sure, only a few of the letters seem truly significant, and it would of course be a mistake to allow the rather informal and ad hoc remarks in any of the letters to eclipse either theorist's considered and matured published reflections. Moreover, the correspondence peters out in the mid-fifties, after which each thinker arguably made important modifications in his respective outlook. But the letters, or at least the most significant, do not seem careless; the principal issues addressed go to the very heart of things; and if the letters are interpreted with careful attention to the contemporary published, as well as some unpublished, writings, then, it seems to me, the engagement between the two theorists does indeed clarify some of the more obscure but weighty premises and implications of the two philosophic positions.
Leo Strauss and the American Founding
Authors: West Thomas G.
Published: August 2009

Strauss devoted his life to the recovery of classical political philosophy. The incentive for this enterprise was what Strauss called “the crisis of the West.” That crisis “consists in the West's having become uncertain of its purpose,” which was to establish the good society on the basis of reason and science. Twentith-century history revealed that the progressive spread of democracy throughout the world was hardly assured. Moreover, the “good society” of Western liberalism no longer looked unquestionably good. Modern philosophy eventually concluded that reason itself was to blame: not only could reason not establish the good society; it could not even say what the good society is.
Without Malice But with Forethought: A Response to Burnyeat
Authors: Levlne David Lawrence
Published: August 2009

The work of Leo Strauss is not typical of American academics. He has explicitly rejected the premises and methodologies of modern scholarship. In its stead, he claims to have rediscovered other, more ancient methods of discovery to guide his research. As a result, his conclusions do not necessarily reconfirm what we think we already know. Hence his work represents a challenge to current scholarship. For if Strauss 's conclusions are true, then a radical rethinking of the history of philosophy, political philosophy and psychology is required. It would be much easier if we could simply say that Strauss's methods and conclusions are wholly misguided.
Reinhold Niebuhr's “Christian Pragmatism”: A Principled Alternative to Consequentialism
Authors: Haas Mark L.
Published: August 2009

Although the influence of Reinhold Niebuhr's thought on political theory has been a profound one, curiously, scholars have quite often misunderstood or misinterpreted his philosophy on issues that are of central importance to his political vision. Specifically, Niebuhr's program for ethical and political action is often described as one of “unrestricted” consequentialism, in which ethical decision making is by necessity reduced to a process where the ends justify the means. Despite the fact that Niebuhr's theory of ethics clearly called for an examination of the likely consequences of one's actions, it should nevertheless not be labeled in this manner.
The Theory of Moral Ecology
Authors: Hertzke Allen D.
Published: August 2009

Although scholars use the termmoral ecologyand commentators frequently employ environmental analogies in depicting the cultural milieu, the profound implications of such formulations remain unexplored. This article provides the first systematic analysis of the theory of moral ecology as a philosophical, empirical, and practical construct. It applies environmental thought, particularly insights from the “tragedy of the commons,” to the moral and cultural realm. It suggests that the concept of moral ecology is a compelling depiction of genuine human dynamics. Corroboration flows from the way the theory of moral ecology synthesizes a vast empirical literature on media violence, family decline, and gambling into a parsimonious nomological formulation.
The processing and comprehension of wh-questions among second language speakers of German
Authors: JACKSON CARRIE N. , BOBB SUSAN C.
Published: July 2009

Using the self-paced reading paradigm, the present study examines whether highly proficient second language (L2) speakers of German (English first language) use case-marking information during the on-line comprehension of unambiguous wh-extractions, even when task demands do not draw explicit attention to this morphosyntactic feature in German. Results support previous findings, in that both the native and the L2 German speakers exhibited an immediate subject preference in the matrix clause, suggesting they were sensitive to case-marking information. However, only among the native speakers did this subject preference carry over to reading times in the complement clause. The results from the present study are discussed in light of current debates regarding the ability of L2 speakers to attain nativelike processing strategies in their L2.
Effects of large herbivores on murid rodents in a South African savanna
Authors: Hagenah Nicole , Prins Herbert H.T. , Olff Han
Published: July 2009

Our study presents experimentally based results on how large herbivore species affect savanna vegetation and thus murid rodents in the Hluhluwe-iMfolozi Park in KwaZulu-Natal, South Africa. We permanently excluded groups of large herbivore guilds of various body sizes (ranging from white rhino to hares) from sixteen 40 × 40-m plots of vegetation by using different fence types. We determined grass species composition and vegetation height and collected capture–mark–recapture data on murid rodents. Nutrient concentrations of the dominant grass species and rodent diet compositions were analysed. We found that herbivore species of different body sizes had different effects on murid rodents. The exclusion of medium-sized herbivores, such as warthog, impala and nyala increased the abundance of high-quality grass species, especiallyPanicum maximum. However, the dominant rodent speciesLemniscomys rosaliapreferred the most abundant grass species, rather than high-quality grasses. The absence of large bulk feeders, such as zebra, buffalo and white rhino led to an increase in vegetation height. In response, tall vegetation promoted both rodent abundance and species diversity and altered rodent species composition. Ultimately, our results indicate that the greatest effect on murid rodents came from the reduction of vegetation cover by large bulk feeders, which likely increased rodent predation risk.
Effect of rodents on seed fate of five hornbill-dispersed tree species in a tropical forest in north-east India
Authors: Velho Nandini , Datta Aparajita , Isvaran Kavita
Published: July 2009

Hornbills are important dispersers of a wide range of tree species. Many of these species bear fruits with large, lipid-rich seeds that could attract terrestrial rodents. Rodents have multiple effects on seed fates, many of which remain poorly understood in the Palaeotropics. The role of terrestrial rodents was investigated by tracking seed fate of five hornbill-dispersed tree species in a tropical forest in north-east India. Seeds were marked inside and outside of exclosures below 6–12 parent fruiting trees (undispersed seed rain) and six hornbill nest trees (a post-dispersal site). Rodent visitors and seed removal were monitored using camera traps. Our findings suggest that several rodent species, especially two species of porcupine were major on-site seed predators. Scatter-hoarding was rare (1.4%). Seeds at hornbill nest trees had lower survival compared with parent fruiting trees, indicating that clumped dispersal by hornbills may not necessarily improve seed survival. Seed survival in the presence and absence of rodents varied with tree species. Some species (e.g. Polyalthia simiarum) showed no difference, others (e.g. Dysoxylum binectariferum) experienced up to a 64% decrease in survival in the presence of rodents. The differing magnitude of seed predation by rodents can have significant consequences at the seed establishment stage.
Seed rain in a tropical agricultural landscape
Authors: Martínez-Garza Cristina , Flores-Palacios Alejandro , De La Peña-Domene Marines , Howe Henry F.
Published: July 2009

Seed dispersal into fragmented tropical landscapes limits the rate and character of ecological succession between forest remnants. In a novel experiment in recovery of dispersal between forest remnants, 120 1-m2 seed traps were placed in fenced plots in active pasture 90–250 m from forest, and in nearby primary and secondary forests. Total seed rain from December 2006 to January 2008 included 69 135 seeds of 57 woody species. High richness of seed rain of early-successional trees occurred in all habitats, but seed rain of late-successional woody plants was much lower into pastures and secondary forest than into old-growth forest. Non-metric ordination analysis further demonstrated high movement of late-successional species within and between forest and secondary forest, but little movement of species of either forest type to pastures. Most species were dispersed by animals, but most seeds were dispersed by wind. A pattern of seed rain biased strongly towards wind-dispersed species creates a template for regeneration quite unlike that in nearby forest.
Jaguar (Panthera onca) hunting activity: effects of prey distribution and availability
Authors: Carrillo Eduardo , Fuller Todd K. , Saenz Joel C.
Published: July 2009

Geographic variation in behaviour of individuals within a species is well known (Foster & Endler 1999), both across ranges (Iriarteet al. 1990) and locally (Hertz & Huey 1981). For predators, variation in prey use within a given site is often seasonal (Brillhart & Kaufman 1995), and related to changes in relative abundance and/or vulnerability of various prey (Kunkelet al. 2004). Behavioural diversity also occurs because prey behaviours vary and predators change foraging tactics, even on a daily basis (Ropert-Coudertet al. 2002).
Counting on the Unexpected: Aimé Civiale's Mountain Photography
Authors: von Brevern Jan
Published: July 2009

Argument

Aimé Civiale's attempt at a complete photographic coverage of the High Alps seems to be a peculiar project at first sight. Carried out between 1859 and 1868, this was the earliest systematic attempt to introduce photography as a medium for studying the earth sciences. But as precise and determined as Civiale's approach appears, it was still quite unclear at the time how exactly photography could be useful in geology. This paper asks where the great confidence in the new medium in regard to mountain representations came from. The answer is not an easy one, as sources on Civiale's project are scarce. To make things even more difficult, the confidence in photography in the earth sciences during that time seems to have been based more on hope than on actual results. It is difficult to extract hope from written sources, let alone from images. I argue that this confidence was not so much based on photography's classic attributes of exactness or objectivity, but on its promise to produce unexpected results. Therefore this argument will inevitably have speculative elements. Thus, this paper can also be understood as an attempt to deal with a specific historiographical problem that regularly occurs when writing about images.
Lessons from Nigeria: the role of roads in the geo-temporal progression of avian influenza (H5N1) virus
Authors: RIVAS A. L. , CHOWELL G. , SCHWAGER S. J. , FASINA F. O. , HOOGESTEIJN A. L. , SMITH S. D. , BISSCHOP S. P. R. , ANDERSON K. L. , HYMAN J. M.
Published: August 2009

The daily progression of the 2006 (January–June) Nigerian avian influenza (AI H5N1) epidemic was assessed in relation to both spatial variables and the generation interval of the invading virus. Proximity to the highway network appeared to promote epidemic dispersal: from the first AI generation interval onwards >20% of all cases were located at <5 km from the nearest major road. Fifty-seven per cent of all cases were located ⩽31 km from three highway intersections. Findings suggest that the spatial features of emerging infections could be key in their control. When the spatial location of a transmission factor is well known, such as that of the highway network, and a substantial percentage of cases (e.g. >20%) are near that factor, early interventions focusing on transmission factors, such as road blocks that prevent poultry trade, may be more efficacious than interventions applied only to the susceptible population.
THELESSER LEARNING FOR WOMENAND OTHER TEXTS FOR VIETNAMESE WOMEN: A BIBLIOGRAPHICAL AND COMPARATIVE STUDY
Authors: Kornicki Peter , Oanh Nguyễn Thị
Published: July 2009

Chinese conduct books for women were read throughout East Asia, but because Chinese was considered too difficult for women in Japan, Korea and Vietnam, vernacular editions often were prepared in order to make the message more accessible. In this article we present a bibliographic study of surviving conduct books for Vietnamese women, both in Chinese and in Vietnamese, and in manuscript and printed forms, and consider the production of such texts in the light of conduct literature for women produced in Korea and Japan. A particularly interesting case isLesser learning for women, a hybrid book combining a Ming-dynasty didactic text in Chinese with other didactic materials in Vietnamese. For the most part, these various conduct books for women purvey unchanging moral certainties and restrictions for women, and as such were increasingly at odds with the changing world of colonial Vietnam in which educational opportunities for women were growing.
CULTURAL DISCOURSE ON XUE SUSU, A COURTESAN IN LATE MING CHINA
Authors: Berg Daria
Published: July 2009

This paper investigates perceptions of courtesans, gender and power from various perspectives, using both literary and non-literary sources and reconstructed lost books. Analysis focuses on representations of the celebrated courtesan, poet and painter Xue Susu (fl. 1575–before 1652) by writers of different backgrounds, gender and class. In late Ming times women participated in elite culture in unprecedented numbers. Courtesans gained prominence in the literati arts, playing a formative role in shaping cultural ideals. Late imperial Chinese discourse embeds the image of the courtesan in the formation of new beauty ideals and social negotiations of gender roles and power. Paradoxes abound, linking the courtesan with notions of chivalry, chastity and loyalism and depicting her in the context of national politics and warfare. The Ming/Qing texts reflect not only current perceptions of women and courtesans, but also the social and cultural aspirations, dreams, anxieties and desires of their authors.
Assessment of Psychopathic Traits in Children and Adolescents
Authors: Bijttebier Patricia , Decoene Stef
Published: August 2009

The study examined the reliability and validity of the Antisocial Process Screening Device (APSD) and the Childhood Psychopathy Scale (CPS) in a community sample of 182 Flemish adolescents in the age range of 9 to 19 years. Data were gathered by means of parent, teacher, and self-report, and the factor structure was examined by means of confirmatory factor analysis. Internal consistencies of the resulting scales and associations with measures of disruptive behavior disorders and internalizing problem behaviors were explored. Results confirmed the underlying a priori structure of both APSD and CPS.
Ozone photochemical production in urban Shanghai, China: Analysis based on ground level observations
Authors: Ran Liang , Zhao Chunsheng , Geng Fuhai , Tie Xuexi , Tang Xu , Peng Li , Zhou Guangqiang , Yu Qiong , Xu Jianmin , Guenther Alex
Published: July 2009

Ozone and its precursors were measured from 15 June 2006 to 14 June 2007 at an urban site in Shanghai and used to characterize photochemical oxidant production in this region. During the observation period, ozone displays a seasonal variation with a maximum in spring. Observed nitrogen oxides (NOx) and carbon monoxide (CO) reached a maximum in winter and a minimum in summer. NOx and CO has a similar double‐peak diurnal cycle, implying that they are largely of motor vehicle origin. Total nonmethane organic compounds (NMOC) concentrations averaged over the morning, and the 24‐hour periods have a large day‐to‐day variation with no apparent seasonal cycle. Aromatics play a dominant role in contributing to total NMOC reactivity and ozone‐forming potential. Anthropogenic NMOC of diverse sources are major components of total NMOC and consist mainly of moderate and low reactivity species. In contrast, relatively low levels of biogenic NMOC concentrations were observed in urban Shanghai. The early morning NMOC/NOx ratios are typically below 8:1 with an average of around 4:1, indicating that the sampling location is situated in a NMOC‐limited regime. Model simulations confirm that potential photochemical ozone production in Shanghai is NMOC‐sensitive. It is presently difficult to predict the impact of future human activities, such as the increase of automobiles and vegetation‐covered landscapes and the reduction of aerosol on ozone pollution in the fast developing megacities of China, and additional studies are needed to better understand the highly nonlinear ozone problem.
Temperature of mesospheric ice retrieved from the O‐H stretch band
Authors: Petelina S. V. , Zasetsky A. Y.
Published: July 2009

For the first time, the temperature of mesospheric ice particles is retrieved directly from ice infrared extinction spectra measured in the solar occultation regime. The position of ice O‐H stretch band peak varies from 3230cm−1 at T = 120K to 3246cm−1 at T = 155K, which enables the retrieval of ice temperature by fitting a model spectrum to a measured one. The retrieved temperature is independent of cloud vertical and horizontal patchiness and has a random uncertainty of <12K. The retrieval is sensitive to chosen particle shape: cubes, hexagons and spheroids of certain forms give same result. Spheres and rectangular prisms (aspect ratio ≥2) change temperature by 3–4K. For nearly 400 ice spectra analyzed the retrieved temperature for cubes ranges from 120K to 150K with the distribution maximum centered at ∼135K. The standard temperature for same ice spectra retrieved from the gas phase differs considerably and sometimes reaches values of 200K and above.
Ice particle growth in the polar summer mesosphere: Formation time and equilibrium size
Authors: Zasetsky A. Y. , Petelina S. V. , Remorov R. , Boone C. D. , Bernath P. F. , Llewellyn E. J.
Published: July 2009

The growth kinetics for ice particles in the polar summer mesosphere is studied using the density of water vapor, temperature, and total ice volume simultaneously measured by the infrared Fourier Transform Spectrometer on the Atmospheric Chemistry Experiment (ACE‐FTS) satellite. The results are based solely on the ACE‐FTS retrievals, without using any adjustable parameters. The computed particle formation time is in the range between 2 hours at 150 K and 20 hours at 120 K, during which particles come to equilibrium with water vapor and reach the size of 20–70 nm. The growth rate varies from 0.2 nm/hour to 30 nm/hour in the temperature range analyzed. As it takes ice crystals only 20 minutes to grow by 10 nm at 150 K, the transition from optically subvisible to the visible size range can occur on a time scale of minutes. This could account for fast variations in PMC brightness observed recently.
Lysozyme retention on hydrophobic interaction chromatography predicts resin performance at large scale
Authors: Riske Frank J. , Smith Michael A. , Zhang Cheng , White Kerry H.
Published: August 2009

It is critical that manufacturers understand the impact of resin variability on process performance and consistency. Choosing an appropriate resin lot often requires running manufacturing load material on a scale‐down processing step and showing that the product recovery and purity is within manufacturing experience. In the present study, the LR (lysozyme retention value), on the vendor Certificate of Analysis, was predictive of the performance of an HIC (hydrophobic interaction chromatography) resin in a complex manufacturing step. This processing step is used to reduce host cell PIs (protein impurities) while maintaining a desired glycoform profile of recombinant TSH (thyroid‐stimulating hormone). A correlation was found between a first‐moment analysis of the HIC elution peaks and resin LR. Approximately 91% of the observed variation was accounted for by resin LR, and LRs of 55 and 50 were significantly different. The acceptable LR range, to maximize glycoform profile reproducibility and minimize recovery fluctuations, was dependent on the product collection method. Only resins with a narrow LR range within 1–2 units would be acceptable in a procedure in which set volume fractions are collected. Resins with an LR from 49 to 55 were appropriate when TSH collection was based on A280 ranges and this approach had the added benefit of collecting a single product pool.
Nonlinear gyrokinetic theory for steady-state mirror mode magnetic structures
Authors: Jovanović D. , Shukla P. K.
Published: August 2009

The analytic study of the saturated state of the mirror instability is presented. The perpendicular ion momentum is described by the hydrodynamic equations, with the finite Larmor radius corrections found from the collisionless stress tensor, while the ion density, the parallel flow, and the pressure are calculated using the gyrokinetic description, accounting for the nonlinear convection by the grad-B drift. Within such a model and using a generalized Schamel's distribution function for the trapped ions, it is possible to study fully nonlinear wave-particle interactions, including the contributions of the finite ion Larmor radius correction and of the trapped ions. The numerical solution reveals the bistability in the stationary regime. Two different nonlinear solutions are found under the same physical conditions, in the form of magnetic humps and magnetic holes, resulting from the wave-wave and wave-particle couplings, respectively. The trapped particles are found to be heated in the parallel direction and their temperature is almost isotropic. The solution is in a good agreement with the magnetic structures observed in the magnetosheath within the solar system and in computer simulations. It provides an explanation for the transformation of humps into holes, as observed in recent computer simulations.
Analysis of liquid mediated friction during alignment in large area UV imprint lithography
Authors: Kang Seock Hwan , Park Si Hwan , Lee Woo Il
Published: August 2009

Stiction in large area imprint lithography was studied by a microtribological approach. As imprinting area is expanded, fine aligning movement can be hindered by the adhesion or in-plane friction between the mold and the substrate. In this study, an analytical model for stiction force in the alignment process was proposed and evaluated by measuring the friction force between two plates mediated by a thin liquid film. Experimental verification was conducted for various geometries and surface conditions. Analytic and experimental results demonstrated that the meniscus force induced from surface tension was the most critical parameter affecting stiction in an alignment process.
Emission of terahertz radiation from SiC
Authors: Strait Jared H. , George Paul A. , Dawlaty Jahan , Shivaraman Shriram , Chandrashekhar Mvs , Rana Farhan , Spencer Michael G.
Published: August 2009

We report the emission of strong coherent broadband terahertz radiation from 6H-silicon-carbide (SiC) excited with optical pulses. The measured terahertz spectral signal-to-noise ratio is better than one thousand. We determine that the terahertz radiation is generated via second order optical nonlinearity (optical rectification). We present a measurement of the ratio of nonlinear susceptibility tensor elements χzzz(2)/χzxx(2) and the complex index of refraction of silicon carbide at terahertz frequencies.
Enhanced transmission through a subwavelength aperture using metamaterials
Authors: Cakmak Atilla Ozgur , Aydin Koray , Colak Evrim , Li Zhaofeng , Bilotti Filiberto , Vegni Lucio , Ozbay Ekmel
Published: August 2009

We report an enhanced transmission through a single circular subwavelength aperture that is incorporated with a split ring resonator (SRR) at the microwave regime. Transmission enhancement factors as high as 530 were observed in the experiments when the SRR was located in front of the aperture in order to efficiently couple the electric field component of the incident electromagnetic wave at SRR’s electrical resonance frequency. The experimental results were supported by numerical analyses. The physical origin of the transmission enhancement phenomenon was discussed by examining the induced surface currents on the structures.
Obama and Medvedev set new limits on nuclear arsenals; further cuts likely
Authors: Kramer David
Published: July 2009

In Moscow, the two leaders reaffirmed commitments to curb proliferation, but differences remain over the US plan for a missile shield in Europe.
Modelling seasonality of dry matter partitioning and root maintenance respiration in lucerne (Medicago sativa L.) crops
Authors: Teixeira Edmar I. , Moot Derrick J. , Brown Hamish E.
Published: August 2009

In lucerne, a dynamic fraction of total daily assimilates is allocated to the root system and the amount partitioned differs in response to seasonal environmental stimuli. This study proposes a simple framework to quantify this dynamic for inclusion in lucerne simulation models. The framework incorporates recent findings on radiation-use efficiency, radiation interception, and dry matter (DM) partitioning to shoots and roots in response to environmental factors. Results showed that the root mean squared deviation (RMSD) between observed and simulated values was 20% of the mean for shoot biomass and 24% for leaf area index. However, there was systematic bias (73% of RMSD) between observed and simulated root biomass (RMSD = 35%). This was caused by the initial assumption of a constant rate for root maintenance respiration (Rm) of 0.015 g/g.day in the model calculations. Sensitivity analysis, with constant Rm values that ranged from 0.005 to 0.030 g/g.day, failed to improve the prediction of root biomass. The modelling exercise suggested the existence of a systematic pattern of change in Rm from 0.035 g/g.day in summer to <0.005 g/g.day in winter. When this seasonality was incorporated, the accuracy of root DM simulations improved (RMSD = 14%). The possible existence of a seasonal Rm in lucerne, unveiled by this modelling approach, needs to be validated with an independent dataset.
The crystal structure of the C-terminus of adseverin reveals the actin-binding interface
Authors: Chumnarnsilpa Sakesit , Lee Wei Lin , Nag Shalini , Kannan Balakrishnan , Larsson Mårten , Burtnick Leslie D. , Robinson Robert C.
Published: August 2009

Adseverin is a member of the calcium-regulated gelsolin superfamily of actin severing and capping proteins. Adseverin comprises 6 homologous domains (A1–A6), which share 60% identity with the 6 domains from gelsolin (G1–G6). Adseverin is truncated in comparison to gelsolin, lacking the C-terminal extension that masks the F-actin binding site in calcium-free gelsolin. Biochemical assays have indicated differences in the interaction of the C-terminal halves of adseverin and gelsolin with actin. Gelsolin contacts actin through a major site on G4 and a minor site on G6, whereas adseverin uses a site on A5. Here, we present the X-ray structure of the activated C-terminal half of adseverin (A4–A6). This structure is highly similar to that of the activated form of the C-terminal half of gelsolin (G4–G6), both in arrangement of domains and in the 3 bound calcium ions. Comparative analysis of the actin-binding surfaces observed in the G4–G6/actin structure suggests that adseverin in this conformation will also be able to interact with actin through A4 and A6, whereas the A5 surface is obscured. A single residue mutation in A4–A6 located at the predicted A4/actin interface completely abrogates actin sequestration. A model of calcium-free adseverin, constructed from the structure of gelsolin, predicts that in the absence of a gelsolin-like C-terminal extension the interaction between A2 and A6 provides the steric inhibition to prevent interaction with F-actin. We propose that calcium binding to the N terminus of adseverin dominates the activation process to expose the F-actin binding site on A2.
Probing the evolution of appendage specialization by Hox gene misexpression in an emerging model crustacean
Authors: Pavlopoulos Anastasios , Kontarakis Zacharias , Liubicich Danielle M. , Serano Julia M. , Akam Michael , Patel Nipam H. , Averof Michalis
Published: August 2009

Changes in the expression of Hox genes have been widely linked to the evolution of animal body plans, but functional demonstrations of this relationship have been impeded by the lack of suitable model organisms. A classic case study involves the repeated evolution of specialized feeding appendages, called maxillipeds, from anterior thoracic legs, in many crustacean lineages. These leg-to-maxilliped transformations correlate with the loss of
Ultrabithorax
(
Ubx
) expression from corresponding segments, which is proposed to be the underlying genetic cause. To functionally test this hypothesis, we establish tools for conditional misexpression and use these to misexpress
Ubx
in the crustacean
Parhyale hawaiensis
. Ectopic
Ubx
leads to homeotic transformations of anterior appendages toward more posterior thoracic fates, including maxilliped-to-leg transformations, confirming the capacity of
Ubx
to control thoracic (leg) versus gnathal (feeding) segmental identities. We find that maxillipeds not only are specified in the absence of
Ubx
, but also can develop in the presence of low/transient
Ubx
expression. Our findings suggest a path for the gradual evolutionary transition from thoracic legs to maxillipeds, in which stepwise changes in Hox gene expression have brought about this striking morphological and functional transformation.
A phosphoenzyme mimic, overlapping catalytic sites and reaction coordinate motion for human NAMPT
Authors: Burgos Emmanuel S. , Ho Meng-Chiao , Almo Steven C. , Schramm Vern L.
Published: August 2009

Nicotinamide phosphoribosyltransferase (NAMPT) is highly evolved to capture nicotinamide (NAM) and replenish the nicotinamide adenine dinucleotide (NAD
+
) pool during ADP-ribosylation and transferase reactions. ATP-phosphorylation of an active-site histidine causes catalytic activation, increasing NAM affinity by 160,000. Crystal structures of NAMPT with catalytic site ligands identify the phosphorylation site, establish its role in catalysis, demonstrate unique overlapping ATP and phosphoribosyltransferase sites, and establish reaction coordinate motion. NAMPT structures with beryllium fluoride indicate a covalent H247-BeF
3
−
as the phosphohistidine mimic. Activation of NAMPT by H247-phosphorylation causes stabilization of the enzyme-phosphoribosylpyrophosphate complex, permitting efficient capture of NAM. Reactant and product structures establish reaction coordinate motion for NAMPT to be migration of the ribosyl anomeric carbon from the pyrophosphate leaving group to the nicotinamide-N1 while the 5-phosphoryl group, the pyrophosphate moiety, and the nicotinamide ring remain fixed in the catalytic site.
A loss-of-function nonsynonymous polymorphism in the osmoregulatory TRPV4 gene is associated with human hyponatremia
Authors: Tian Wei , Fu Yi , Garcia-Elias Anna , Fernández-Fernández José M. , Vicente Rubén , Kramer Patricia L. , Klein Robert F. , Hitzemann Robert , Orwoll Eric S. , Wilmot Beth , McWeeney Shannon , Valverde Miguel A. , Cohen David M.
Published: August 2009

Disorders of water balance are among the most common and morbid of the electrolyte disturbances, and are reflected clinically as abnormalities in the serum sodium concentration. The transient receptor potential vanilloid 4 (TRPV4) channel is postulated to comprise an element of the central tonicity-sensing mechanism in the mammalian hypothalamus, and is activated by hypotonic stress in vitro. A nonsynonymous polymorphism in the
TRPV4
gene gives rise to a Pro-to-Ser substitution at residue 19. We show that this polymorphism is significantly associated with serum sodium concentration and with hyponatremia (serum sodium concentration ≤135 mEq/L) in 2 non-Hispanic Caucasian male populations; in addition, mean serum sodium concentration is lower among subjects with the TRPV4
P19S
allele relative to the wild-type allele. Subjects with the minor allele were 2.4−6.4 times as likely to exhibit hyponatremia as subjects without the minor allele (after inclusion of key covariates). Consistent with these observations, a human TRPV4 channel mutated to incorporate the TRPV4
P19S
polymorphism showed diminished response to hypotonic stress (relative to the wild-type channel) and to the osmotransducing lipid epoxyeicosatrienoic acid in heterologous expression studies. These data suggest that this polymorphism affects TRPV4 function in vivo and likely influences systemic water balance on a population-wide basis.
Toward a microscopic model of bidirectional synaptic plasticity
Authors: Castellani Gastone C. , Bazzani Armando , Cooper Leon N
Published: July 2009

We show that a 2-step phospho/dephosphorylation cycle for the α-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid receptor (AMPAR), as used in in vivo learning experiments to assess long-term potentiation (LTP) induction and establishment, exhibits bistability for a wide range of parameters, consistent with values derived from biological literature. The AMPAR model we propose, hence, is a candidate for memory storage and switching behavior at a molecular-microscopic level. Furthermore, the stochastic formulation of the deterministic model leads to a mesoscopic interpretation by considering the effect of enzymatic fluctuations on the Michelis–Menten average dynamics. Under suitable hypotheses, this leads to a stochastic dynamical system with multiplicative noise whose probability density evolves according to a Fokker–Planck equation in the Stratonovich sense. In this approach, the probability density associated with each AMPAR phosphorylation state allows one to compute the probability of any concentration value, whereas the Michaelis–Menten equations consider the average concentration dynamics. We show that bistable dynamics are robust for multiplicative stochastic perturbations and that the presence of both noise and bistability simulates LTP and long-term depression (LTD) behavior. Interestingly, the LTP part of this model has been experimentally verified as a result of in vivo, one-trial inhibitory avoidance learning protocol in rats, that produced the same changes in hippocampal AMPARs phosphorylation state as observed with in vitro induction of LTP with high-frequency stimulation (HFS). A consequence of this model is the possibility of characterizing a molecular switch with a defined biochemical set of reactions showing bistability and bidirectionality. Thus, this 3-enzymes-based biophysical model can predict LTP as well as LTD and their transition rates. The theoretical results can be, in principle, validated by in vitro and in vivo experiments, such as fluorescence measurements and electrophysiological recordings at multiple scales, from molecules to neurons. A further consequence is that the bistable regime occurs only within certain parametric windows, which may simulate a “history-dependent threshold”. This effect might be related to the Bienenstock–Cooper–Munro theory of synaptic plasticity.
Conformational selection or induced fit: A flux description of reaction mechanism
Authors: Hammes Gordon G. , Chang Yu-Chu , Oas Terrence G.
Published: July 2009

The mechanism of ligand binding coupled to conformational changes in macromolecules has recently attracted considerable interest. The 2 limiting cases are the “induced fit” mechanism (binding first) or “conformational selection” (conformational change first). Described here are the criteria by which the sequence of events can be determined quantitatively. The relative importance of the 2 pathways is determined not by comparing rate constants (a common misconception) but instead by comparing the flux through each pathway. The simple rules for calculating flux in multistep mechanisms are described and then applied to 2 examples from the literature, neither of which has previously been analyzed using the concept of flux. The first example is the mechanism of conformational change in the binding of NADPH to dihydrofolate reductase. The second example is the mechanism of flavodoxin folding coupled to binding of its cofactor, flavin mononucleotide. In both cases, the mechanism switches from being dominated by the conformational selection pathway at low ligand concentration to induced fit at high ligand concentration. Over a wide range of conditions, a significant fraction of the flux occurs through both pathways. Such a mixed mechanism likely will be discovered for many cases of coupled conformational change and ligand binding when kinetic data are analyzed by using a flux-based approach.
Connectionist modelling of Aspect acquisition in Italian L2
Authors: Rosi Fabiana
Published: August 2009

Within the long tradition of second language acquisition (SLA) research on the development of the category of Aspect (Dietrich et al. 1995; Giacalone Ramat 2002), the present study compares the acquisitional pattern observed in learners of Italian L2 and those obtained by connectionist simulations, namely unsupervised neural networks, Self Organizing Maps, SOMs (Kohonen 2001). The research tests empirically whether SOMs can display the emergence of Aspect in the interlanguage produced by German-speaking and Spanish-speaking L2 learners and the interaction between Aspect, Actionality and Grounding in this development. The convergence between connectionist modelling and learners’ patterns provides evidence for the interaction that exists between data-driven mechanisms and cognitive principles in the complex process of second language acquisition.
The prognostic significance of heart failure with preserved left ventricular ejection fraction: a literature‐based meta‐analysis
Authors: Somaratne Jithendra B. , Berry Colin , McMurray John J.V. , Poppe Katrina K. , Doughty Robert N. , Whalley Gillian A.
Published: August 2009

Aims

Heart failure (HF) with normal or preserved left ventricular (LV) ejection fraction (HFPEF) has been reported to be associated with similar outcome as HF with reduced EF (HFREF) in registry‐based and epidemiological analyses, but many of these studies excluded patients who did not have EF measurements. Conversely, prior prospective studies have reported better outcome for patients with HFPEF. We performed a meta‐analysis of prospective observational studies comparing all‐cause mortality in patients with HFREF and HFPEF.

Methods and results

We searched several online databases for studies comparing outcome in HFREF and HFPEF, published before 2007. Inclusion criteria: prospective, clinical HF, near complete EF data, and mortality outcome. Review Manager version 4.2.3 software was used for the analysis. Overall, 24 501 patients [9299 deaths (38%)] from 17 studies are included. Average follow‐up was 47 months; the HFPEF group was older (69 vs. 66 years) and more likely to be female (44% vs. 26%). Of the 7688 patients with HFPEF 2468 died (32.1%), compared with 6831 of the 16 813 patients with HFREF (40.6%): odds ratio 0.51 (95% CI: 0.48, 0.55).

Conclusion

This literature‐based meta‐analysis demonstrates that mortality among patients with HFPEF was half that observed in those with HFREF, in contrast to previous reports suggesting that mortality may be similar between both groups.