bluuebunny/crossref_metadata_2025 huggingface dataset:
Replica exchange with dynamical scaling
Authors: Rick Steven W.
Published: February 2007

A replica exchange method is presented which requires fewer replicas and is designed to be used for large systems. In this method, dynamically scaled replicas are placed between conventional replicas at broadly spaced temperatures. The potential of the scaled replicas is linearly scaled by a dynamical variable which varies between 0 and 1. When the variable is near either end point the replica can undergo exchanges with one of its neighboring replicas. Two different versions of the method are presented for a model system of a small peptide in water. The scaled replica can replace many replicas and the method can be up to ten times more efficient than conventional replica exchange.
Resonant control of the characteristic temperatures T0 and T1 of AlInGaAs 0.8μm semiconductor lasers with delta-doped tunneling quantum wells
Authors: Fekete D.
Published: February 2007

It is demonstrated experimentally that AlInGaAs∕GaAs lasers with Te n-type δ-doped resonant tunneling quantum wells (QWs), tuned to operate at resonance at elevated temperature, exhibit higher external efficiency and improved temperature stability. These lasers were designed to ensure that the decrease in the band bending (which results from the increased current density at threshold due to the elevated temperature) would cause the ground-state levels in the two QWs to coincide, thus obtaining enhanced coupling between the QWs. The enhanced coupling increases the efficiency and reduces the transparency current which curbs the increase of the threshold current due to the elevated temperature.
Comment on “Convective heat transfer law for an endoreversible engine” [J. Appl. Phys. 100, 014911 (2006)]
Authors: Arias-Hernandez L. A. , Ares de Parga G. , Angulo-Brown F.
Published: February 2007

In this Comment we emphasize that the Huleihil and Andresen approximation for the exponent of the convective heat transfer law expressed as n=1+ε, with ε a small number which is representative of convective heat transfer, is a reasonable proposal, and additionally it works well for another optimization criteria. We also show that some of the main analytical results of the article [M. Huleihil and B. Andresen, J. Appl. Phys. 100, 014911 (2006)] are particular cases of expressions previously published in the article [L.A. Arias-Hernandez, G. Ares de Parga, and F. Angulo-Brown, Open Syst. Inf. Dyn. 10, 351 (2003)] where internal irreversibilities were included in the engine models.
Nature of low-energy optical emission in doped AlGaN∕GaN heterostructures
Authors: Belyaev A. E. , Naumov A. V. , Tarasov G. G. , Komarov A. V. , Tacano M. , Danylyuk S. V. , Vitusevich S. A.
Published: February 2007

Photoluminescence (PL) in modulation-doped and nominally undoped AlxGa1−xN∕GaN heterostructures was studied and compared with PL spectra of GaN films grown on sapphire substrates. It is demonstrated that optical emission in the energy range of 3.3–3.46eV related to the two-dimensional electron gas radiative processes can be completely suppressed in modulation-doped AlxGa1−xN∕GaN heterostructures. Instead of this, an intense broad long-wavelength emission attributed to the recombination of donor-acceptor pairs in the lower energy range of 2.7–3.3eV is revealed. This spectral transformation is explained by the presence of deep-level defect-related acceptor centers in AlxGa1−xN∕GaN heterostructures introduced at the modulation doping of the AlxGa1−xN barrier layer.
System for continuous production of nanophase materials using a microwave-driven polyol process
Authors: Gold Steven H. , Bruce Ralph W. , Fliflet Arne W. , Lewis David , Kurihara Lynn K. , Imam M. A.
Published: February 2007

A prototype system is described for the large scale, continuous production of nanophase metals, metal oxides, and other nanophase materials using the polyol process. The polyol process employs an organic solvent such as ethylene glycol to reduce a metal oxide/metal salt at high temperature to the metal oxide or metal. The system employs a 6kW, 2.45GHz microwave source to rapidly heat the continuously flowing solution to a desired process temperature as it flows through a silica tube placed along the center line of a section of waveguide.
Coexistence of exchange-bias fields and vertical magnetization shifts in ZnCoO∕NiO system
Authors: Huang Po-Hsiang , Huang Hsin-Hung , Lai Chih-Huang
Published: February 2007

Exchange fields accompanying vertical magnetization shifts were observed in the epitaxial ZnCo0.07O (dilute magnetic semiconductor)/NiO system after field cooling. Transitions of exchange fields and magnetization shifts were observed at 50K, above which the magnetization shift disappeared and the exchange field was significantly reduced. Both the exchange field and the magnetization shift increased with increasing cooling-field strength at temperatures below 50K, which might be attributed to the existence of “frozen” spins in ZnCoO. The observed linear dependence of the exchange field on the magnetization shift may directly elucidate the role of pinned spins on the exchange fields.
Thermal activation in Au-based bulk metallic glass characterized by high-temperature nanoindentation
Authors: Yang Bing , Wadsworth Jeffrey , Nieh Tai-Gang
Published: February 2007

High-temperature nanoindentation experiments have been conducted on a Au49Ag5.5Pd2.3Cu26.9Si16.3 bulk metallic glass from 30to140°C, utilizing loading rates ranging from 0.1to100mN∕s. Generally, the hardness decreased with increasing temperature. An inhomogeneous-to-homogeneous flow transition was clearly observed when the test temperature approached the glass transition temperature. Analyses of the pop-in pattern and hardness variation showed that the inhomogeneous-to-homogeneous transition temperature was loading-rate dependent. Using a free-volume model, the authors deduced the size of the basic flow units and the activation energy for the homogeneous flow. In addition, the strain rate dependency of the transition temperature was predicted.
In-plane optical anisotropy in self-assembled Ge quantum dots induced by interfacial chemical bonds
Authors: Wei C. M. , Chen T. T. , Chen Y. F. , Peng Y. H. , Kuan C. H.
Published: February 2007

In-plane optical anisotropy has been observed in self-assembled Ge quantum dots (QDs). It is found that the photoluminescence (PL) spectrum polarized along [110] exhibits different features compared to that corresponding to [11¯0]. Besides, the polarized PL spectrum is able to reveal a detailed fine structure much more pronounced than that in the unpolarized spectrum. It is shown that the observed optical anisotropy is a result of the inherent property of the type-II band alignment of Ge QDs embedded in Si matrix. The light emission arises from the recombination of electrons and holes across the interface, and it thus reflects the anisotropic nature of the interfacial chemical bonds.
Slow oscillations in the low-temperature optical reflectance spectra of ZnO: Surface space-charge effect
Authors: Ning J. Q. , Xu S. J. , Shi S. L. , Xie M. H.
Published: February 2007

Low-temperature optical reflectance spectra from (101¯0) surface of a ZnO crystalline rod were measured at near normal incidence. These spectra show slow oscillations which originate from the interference between lights reflected from the front surface and the second surface of a space-charge double layer formed on ZnO (101¯0). It is found that the oscillation period is linearly dependent on the wavelength of light. The expanding rate of the space-charge double layer is estimated to be 1.3nm∕min.
Enhanced piezoelectric effect of relaxor ferroelectrics in nonpolar direction
Authors: Wang L.-F. , Liu J.-M.
Published: February 2007

The polarization and electromechanical behaviors of relaxor ferroelectrics (RFs) are simulated by numerically solving the time-dependent Landau-Ginzburg equation based on a phenomenological dipole defect model. In comparison with normal ferroelectric lattice, the RF lattice shows significantly enhanced piezoelectric response along the nonspontaneous polarization axis. The evolution of dipole configuration suggests that this behavior is ascribed to the 90° flips of small-sized “super-ferroelectric” clusters induced by dipole defects.
Lnk negatively regulates self-renewal of hematopoietic stem cells by modifying thrombopoietin-mediated signal transduction
Authors: Seita Jun , Ema Hideo , Ooehara Jun , Yamazaki Satoshi , Tadokoro Yuko , Yamasaki Akiko , Eto Koji , Takaki Satoshi , Takatsu Kiyoshi , Nakauchi Hiromitsu
Published: February 2007

One of the central tasks of stem cell biology is to understand the molecular mechanisms that control self-renewal in stem cells. Several cytokines are implicated as crucial regulators of hematopoietic stem cells (HSCs), but little is known about intracellular signaling for HSC self-renewal. To address this issue, we attempted to clarify how self-renewal potential is enhanced in HSCs without the adaptor molecule Lnk, as in Lnk-deficient mice HSCs are expanded in number >10-fold because of their increased self-renewal potential. We show that Lnk negatively regulates self-renewal of HSCs by modifying thrombopoietin (TPO)-mediated signal transduction. Single-cell cultures showed that Lnk-deficient HSCs are hypersensitive to TPO. Competitive repopulation revealed that long-term repopulating activity increases in Lnk-deficient HSCs, but not in WT HSCs, when these cells are cultured in the presence of TPO with or without stem cell factor. Single-cell transplantation of each of the paired daughter cells indicated that a combination of stem cell factor and TPO efficiently induces symmetrical self-renewal division in Lnk-deficient HSCs but not in WT HSCs. Newly developed single-cell immunostaining demonstrated significant enhancement of both p38 MAPK inactivation and STAT5 and Akt activation in Lnk-deficient HSCs after stimulation with TPO. Our results suggest that a balance in positive and negative signals downstream from the TPO signal plays a role in the regulation of the probability of self-renewal in HSCs. In general, likewise, the fate of stem cells may be determined by combinational changes in multiple signal transduction pathways.
Monocyte chemoattractant protein 1 mediates retinal detachment-induced photoreceptor apoptosis
Authors: Nakazawa Toru , Hisatomi Toshio , Nakazawa Chifuyu , Noda Kosuke , Maruyama Kazuichi , She Haicheng , Matsubara Akihisa , Miyahara Shinsuke , Nakao Shintaro , Yin Yuqin , Benowitz Larry , Hafezi-Moghadam Ali , Miller Joan W.
Published: February 2007

Photoreceptor apoptosis is a major cause of visual loss in retinal detachment (RD) and several other visual disorders, but the underlying mechanisms remain elusive. Recently, increased expression of monocyte chemoattractant protein 1 (MCP-1) was reported in vitreous humor samples of patients with RD and diabetic retinopathy as well as in the brain tissues of patients with neurodegenerative diseases, including Alzheimer's disease and multiple sclerosis. Here we report that MCP-1 plays a critical role in mediating photoreceptor apoptosis in an experimental model of RD. RD led to increased MCP-1 expression in the Müller glia and increased CD11b
+
macrophage/microglia in the detached retina. An MCP-1 blocking antibody greatly reduced macrophage/microglia infiltration and RD-induced photoreceptor apoptosis. Confirming these results, MCP-1 gene-deficient mice showed significantly reduced macrophage/microglia infiltration after RD and very little photoreceptor apoptosis. In primary retinal mixed cultures, MCP-1 was cytotoxic for recoverin
+
photoreceptors, and this toxicity was eliminated through immunodepleting macrophage/microglia from the culture.
In vivo
, deletion of the gene encoding CD11b/CD18 nearly eliminated macrophage/microglia infiltration to the retina after RD and the loss of photoreceptors. Thus, MCP-1 expression and subsequent macrophage/microglia infiltration and activation are critical for RD-induced photoreceptor apoptosis. This pathway may be an important therapeutic target for preventing photoreceptor apoptosis in RD and other CNS diseases that share a common etiology.
Adaptive genic evolution in the
Drosophila
genomes
Authors: Shapiro Joshua A. , Huang Wei , Zhang Chenhui , Hubisz Melissa J. , Lu Jian , Turissini David A. , Fang Shu , Wang Hurng-Yi , Hudson Richard R. , Nielsen Rasmus , Chen Zhu , Wu Chung-I
Published: February 2007

Determining the extent of adaptive evolution at the genomic level is central to our understanding of molecular evolution. A suitable observation for this purpose would consist of polymorphic data on a large and unbiased collection of genes from two closely related species, each having a large and stable population. In this study, we sequenced 419 genes from 24 lines of
Drosophila melanogaster
and its close relatives. Together with data from
Drosophila simulans
, these data reveal the following. (
i
) Approximately 10% of the loci in regions of normal recombination are much less polymorphic at silent sites than expected, hinting at the action of selective sweeps. (
ii
) The level of polymorphism is negatively correlated with the rate of nonsynonymous divergence across loci. Thus, even under strict neutrality, the ratio of amino acid to silent nucleotide changes (A:S) between
Drosophila
species is expected to be 25–40% higher than the A:S ratio for polymorphism when data are pooled across the genome. (
iii
) The observed A/S ratio between species among the 419 loci is 28.9% higher than the (adjusted) neutral expectation. We estimate that nearly 30% of the amino acid substitutions between
D. melanogaster
and its close relatives were adaptive. (
iv
) This signature of adaptive evolution is observable only in regions of normal recombination. Hence, the low level of polymorphism observed in regions of reduced recombination may not be driven primarily by positive selection. Finally, we discuss the theories and data pertaining to the interpretation of adaptive evolution in genomic studies.
Patching Physics and Chemistry Together
Authors: Bishop Robert C.
Published: February 2007

The “usual story” regarding molecular chemistry is that it is roughly an application of quantum mechanics. That is to say, quantum mechanics supplies everything necessary and sufficient, both ontologically and epistemologically, to reduce molecular chemistry to quantum mechanics. This is a reductive story, to be sure, but a key explanatory element of molecular chemistry, namely molecular structure, is absent from the quantum realm. On the other hand, typical characterizations of emergence, such as the unpredictability or inexplicability of molecular structure based on quantum mechanics, do not characterize the relationship between molecular chemistry and quantum mechanics well either. A different scheme for characterizing reduction and emergence is proposed that accommodates the relationship between quantum mechanics and molecular chemistry and some initial objections to the scheme are considered.
The Large Scale Structure of Logical Empiricism: Unity of Science and the Elimination of Metaphysics
Authors: Frost-Arnold Greg
Published: February 2007

Two central and well-known philosophical goals of the logical empiricists are the unification of science and the elimination of metaphysics. Textual analysis shows, however, that these two apparently distinct planks of the logical empiricist party platform are actually intimately related. From the 1920s through 1950, one abiding criterion for judging whether an apparently declarative assertion or descriptive term is metaphysical is that that assertion or term cannot be incorporated into a language of unified science. I explore various versions of this criterion throughout the works of Carnap and Neurath.
Overextending Partial Structures: Idealization and Abstraction
Authors: Pincock Christopher
Published: February 2007

The partial structures program of da Costa, French and others offers a unified framework within which to handle a wide range of issues central to contemporary philosophy of science. I argue that the program is inadequately equipped to account for simple cases where idealizations are used to construct abstract, mathematical models of physical systems. These problems show that da Costa and French have not overcome the objections raised by Cartwright and Suárez to using model-theoretic techniques in the philosophy of science. However, my concerns arise independently of the more controversial assumptions that Cartwright and Suárez have employed.
To Quantize or Not to Quantize: Fact and Folklore in Quantum Gravity
Authors: Wüthrich Christian
Published: February 2007

Does the need to find a quantum theory of gravity imply that the gravitational field must be quantized? Physicists working in quantum gravity routinely assume an affirmative answer, often without being aware of the metaphysical commitments that tend to underlie this assumption. The ambition of this article is to probe these commitments and to analyze some recently adduced physical—as opposed to metaphysical—arguments pertinent to the issue of quantization. While there exist good reasons to quantize gravity, as this analysis will show, alternative approaches to gravity challenge the received wisdom. These renegade approaches do not regard gravity as a fundamental force, but rather as effective, i.e., as merely supervening on fundamental physics. I will urge that these alternative accounts at least prove the tenability of an opposition to quantization.
Mechanisms and Functional Hypotheses in Social Science
Authors: Steel Daniel
Published: February 2007

Critics of functional explanations in social science maintain that such explanations are illegitimate unless a mechanism is specified. Others argue that mechanisms are not necessary for causal inference and that functional explanations are a type of causal claim that raise no special difficulties for testing. I show that there is indeed a special problem that confronts testing functional explanations resulting from their connection to second-order causal claims. I explain how mechanisms can resolve this difficulty, but argue that this does not provide support for methodological individualism since it is not necessary that the mechanisms be described in terms of individual interactions.
Can Psychology Be a Unified Science?
Authors: Shapiro Lawrence A.
Published: February 2007

Jaegwon Kim has argued that if psychological kinds are multiply realizable then no single psychological theory can describe regularities ranging over psychological states. Instead, psychology must be fractured, with human psychology covering states realized in the human way, martian psychology covering states realized in the martian way, and so on. I show that even if one accepts the principles that motivate Kim's argument, his conclusion does not follow. I then offer a dilemma that forces Kim to concede the possibility of a unified psychology. I close with a discussion of what, according to Jerry Fodor, is “really bugging” Kim.
On the Interplay of the Cognitive and the Social in Scientific Practices
Authors: Lacey Hugh
Published: February 2007

I consider the following questions, central to recent disagreements between Longino and Kitcher: Is it constitutive of making judgments of the cognitive acceptability of theories that they are made under certain social relations that embody specific social values that have been cultivated among investigators (Longino)? Or is making them (sound ones) just a consequence of social interactions that occur under these relations (Kitcher)? While generally endorsing the latter view, I make a distinction, not made by the philosophers under discussion, between sound acceptance and endorsement of a theory, and argue that Longino's view applies to endorsement.
On the Cartesian Ontology of General Relativity: Or, Conventionalism in the History of the Substantival-Relational Debate
Authors: Slowik Edward
Published: February 2007

Using Einstein's comparison of General Relativity and Descartes’ physics, this investigation explores the alleged conventionalism that pervades the ontology of substantival and relationist conceptions of spacetime. Although previously discussed, namely by Rynasiewicz and Hoefer, it will be argued that the close similarities between General Relativity and Cartesian physics have not been adequately treated in the literature—and that the disclosure of these similarities bolsters the case for a conventionalist interpretation of spacetime ontology.
The Upward Path to Structural Realism
Authors: Votsis Ioannis
Published: February 2007

In a recent PSA paper (2001a), as well as some other papers (1995, 2000, 2001b) and a book chapter (1999, Chapter 7), Stathis Psillos raised a number of objections against structural realism. The aim of this paper is threefold: (1) to evaluate part of Psillos’ offence on the Russellian version of epistemic structural realism (ESR); (2) to elaborate more fully what Russellian ESR involves; and (3) to suggest improvements where it is indeed failing.
Structural Distinctions: Entities, Structures, and Changes in Science
Authors: Cei Angelo
Published: February 2007

I argue that the pessimistic meta-induction (PMI) seems to point an ontological priority of the relations over the objects of the scientific theories of the kind suggested by French and Ladyman (2003). My strategy will involve a critical examination of epistemic structural realism (ESR) and an historical case-study: the prediction of Zeeman's effect in Lorentz's theory of the electron.
Genetically enhanced growth causes increased mortality in hypoxic environments
Authors: Sundt-Hansen L , Sundström L.F , Einum S , Hindar K , Fleming I.A , Devlin R.H
Published: February 2007

Rapid growth and development are associated with several fitness-related benefits. Yet, organisms usually grow more slowly than their physiological maximum, suggesting that rapid growth may carry costs. Here we use coho salmon (
Oncorhynchus kisutch
) eggs of wild and transgenic genotypes to test whether rapid growth causes reduced tolerance to low levels of oxygen (hypoxia). Eggs were exposed to four different durations of hypoxia, and survival and growth were recorded until the end of the larval stage. Survival rates decreased with increasing duration of hypoxia, but this decrease was most pronounced for the transgenic group. Larval mass was also negatively affected by hypoxia; however, transgenic genotypes were significantly larger than wild genotypes at the end of the larval stage. Oxygen can be a limiting factor for survival and development in a wide range of organisms, particularly during the egg stage. Thus, the reduced ability of fast-growing genotypes to cope with low oxygen levels identified in the present study may represent a general constraint on evolution of rapid growth across taxa.
When to use social information: the advantage of large group size in individual decision making
Authors: King Andrew J , Cowlishaw Guy
Published: February 2007

Correct decision making is crucial for animals to maximize foraging success and minimize predation risk. Group-living animals can make such decisions by using their own personal information or by pooling information with other group members (i.e. social information). Here, we investigate how individuals might best balance their use of personal and social information. We use a simple modelling approach in which individual decisions based upon social information are more likely to be correct when more individuals are involved and their personal information is more accurate. Our model predicts that when the personal information of group members is poor (accurate less than half the time), individuals should avoid pooling information. In contrast, when personal information is reliable (accurate at least half the time), individuals should use personal information less often and social information more often, and this effect should grow stronger in larger groups. One implication of this pattern is that social information allows less well-informed members of large groups to reach a correct decision with the same probability as more well-informed members of small groups. Thus, animals in larger groups may be able to minimize the costs of collecting personal information without impairing their ability to make correct decisions.
Wolf reintroduction to Scotland: public attitudes and consequences for red deer management
Authors: Nilsen Erlend B , Milner-Gulland E.J , Schofield Lee , Mysterud Atle , Stenseth Nils Chr , Coulson Tim
Published: February 2007

Reintroductions are important tools for the conservation of individual species, but recently more attention has been paid to the restoration of ecosystem function, and to the importance of carrying out a full risk assessment prior to any reintroduction programme. In much of the Highlands of Scotland, wolves (
Canis lupus
) were eradicated by 1769, but there are currently proposals for them to be reintroduced. Their main wild prey if reintroduced would be red deer (
Cervus elaphus
). Red deer are themselves a contentious component of the Scottish landscape. They support a trophy hunting industry but are thought to be close to carrying capacity, and are believed to have a considerable economic and ecological impact. High deer densities hamper attempts to reforest, reduce bird densities and compete with livestock for grazing. Here, we examine the probable consequences for the red deer population of reintroducing wolves into the Scottish Highlands using a structured Markov predator–prey model. Our simulations suggest that reintroducing wolves is likely to generate conservation benefits by lowering deer densities. It would also free deer estates from the financial burden of costly hind culls, which are required in order to achieve the Deer Commission for Scotland's target deer densities. However, a reintroduced wolf population would also carry costs, particularly through increased livestock mortality. We investigated perceptions of the costs and benefits of wolf reintroductions among rural and urban communities in Scotland and found that the public are generally positive to the idea. Farmers hold more negative attitudes, but far less negative than the organizations that represent them.
Pathways to hydrogen as an energy carrier
Authors: Sigfusson Thorsteinn I
Published: February 2007

When hydrogen is used as an alternative energy carrier, it is very important to understand the pathway from the primary energy source to the final use of the carrier. This involves, for example, the understanding of greenhouse gas emissions associated with the production of hydrogen and throughout the lifecycle of a given utilization pathway as well as various energy or exergy
1
efficiencies and aspects involved. This paper which is based on a talk given at the Royal Society in London assesses and reviews the various production pathways for hydrogen with emphasis on emissions, energy use and energy efficiency. The paper also views some aspects of the breaking of the water molecule and examines some new emerging physical evidence which could pave the way to a new and more feasible pathway.

A special attention will be given to the use of the renewable energy pathway. As an example of a hydrogen society that could be based on renewable primary energy, the paper describes the hydrogen society experiments in Iceland as well as unconventional hydrogen obtained from geothermal gases. In the light of our experience, attempts will be made to shed light upon drivers as well as obstacles in the development of a hydrogen society.
Impact of enhanced geothermal systems on US energy supply in the twenty-first century
Authors: Tester Jefferson W , Anderson Brian J , Batchelor Anthony S , Blackwell David D , DiPippo Ronald , Drake Elisabeth M , Garnish John , Livesay Bill , Moore Michal C , Nichols Kenneth , Petty Susan , Nafi Toksoz M , Veatch Ralph W , Baria Roy , Augustine Chad , Murphy Enda , Negraru Petru , Richards Maria
Published: February 2007

Recent national focus on the value of increasing US supplies of indigenous renewable energy underscores the need for re-evaluating all alternatives, particularly those that are large and well distributed nationally. A panel was assembled in September 2005 to evaluate the technical and economic feasibility of geothermal becoming a major supplier of primary energy for US base-load generation capacity by 2050. Primary energy produced from both conventional hydrothermal and enhanced (or engineered) geothermal systems (EGS) was considered on a national scale. This paper summarizes the work of the panel which appears in complete form in a 2006 MIT report, ‘The future of geothermal energy’ parts 1 and 2.

In the analysis, a comprehensive national assessment of US geothermal resources, evaluation of drilling and reservoir technologies and economic modelling was carried out. The methodologies employed to estimate geologic heat flow for a range of geothermal resources were utilized to provide detailed quantitative projections of the EGS resource base for the USA. Thirty years of field testing worldwide was evaluated to identify the remaining technology needs with respect to drilling and completing wells, stimulating EGS reservoirs and converting geothermal heat to electricity in surface power and energy recovery systems. Economic modelling was used to develop long-term projections of EGS in the USA for supplying electricity and thermal energy. Sensitivities to capital costs for drilling, stimulation and power plant construction, and financial factors, learning curve estimates, and uncertainties and risks were considered.
Introduction: Organ Involvement in the Cardiometabolic Syndrome
Authors: Hayden Melvin R. , Stump Craig S. , Sowers James R.
Published: February 2007

The cardiometabolic syndrome is a construct associated with an increased risk of type 2 diabetes mellitus, cardiovascular disease (coronary artery disease , peripheral arterial disease, and stroke), chronic kidney disease, and the metabolic hepatopathy referred to as nonalcoholic fatty liver disease or nonalcoholic steatohepatitis. Thus , the term cardiometabolic syndrome includes all of these metabolic, islet, cardiovascular, renal, and hepatic disorders and clustering clinical syndromes. This overview of the cardiometabolic syndrome is designed to review the clinical complications and the end‐organ cellular and extracellular matrix remodeling events that occur with the cardiometabolic syndrome. The MINER acronym will serve as an outline, representing: Myocardial and metabolic—hepatopathy, Intimal and islet, Neurovascular, Endothelial, and Renal oxidation—reduction (redox) stress and remodeling.
Nonalcoholic Steatohepatitis and the Cardiometabolic Syndrome
Authors: Abdeen Mohammad Basem , Chowdhury Nazif A. , Hayden Melvin R. , Ibdah Jamal A.
Published: February 2007

Nonalcoholic fatty liver disease (NAFLD) is now considered to be the most common liver disease in the United States and involves a spectrum of progressive histopathologic changes. Common risk factors associated with NAFLD include obesity, diabetes, and hyperlipidemia. Although most patients with NAFLD have simple hepatic steatosis, a significant number develop nonalcoholic steatohepatitis , which may progress to fibrosis, cirrhosis, or end‐stage liver disease. There is increasing evidence that NAFLD is a common feature in patients with the cardiometabolic syndrome, a constellation of metabolic , cardiovascular, renal, and inflammatory abnormalities in which insulin resistance is thought to play a key role in end‐organ pathogenesis. NAFLD is usually diagnosed after abnormal liver chemistry results are found during routine laboratory testing. No therapy has been proven effective for treating NAFLD/nonalcoholic steatohepatitis. Expert opinion emphasizes the importance of exercise, weight loss in obese and overweight individuals, treatment of hyperlipidemia, and glucose control.
Examination of the association between syringe exchange program (SEP) dispensation policy and SEP client‐level syringe coverage among injection drug users
Authors: Bluthenthal Ricky N. , Ridgeway Greg , Schell Terry , Anderson Rachel , Flynn Neil M. , Kral Alex H.
Published: February 2007

Aim  To determine whether syringe exchange programs' (SEPs) dispensation policy is associated with syringe coverage among SEP clients.

Design  Cross‐sectional samples of SEPs and their clients.

Setting  SEPs in California, USA.

Participants  Twenty‐four SEPs and their injection drug using (IDU) clients (n = 1576).

Measurements  Clients were classified as having adequate syringe coverage if they received at least as many syringes from the SEP as their self‐reported injections in the last 30 days. SEPs were classified based on their syringe dispensation policy. Dispensation schemes ranging from least restrictive to most are: unlimited needs‐based distribution; unlimited one‐for‐one exchange plus a few additional syringes; per visit limited one‐for‐one plus a few additional syringes; unlimited one‐for‐one exchange; and per visit limited one‐for‐one exchange.

Findings  Adequate syringe coverage among SEP clients by dispensation policy is as follows: unlimited needs‐based distribution = 61%; unlimited one‐for‐one plus = 50%; limited one‐for‐one plus = 41%; unlimited one‐for‐one = 42%; and limited one‐for‐one = 26%. In multivariate analysis, adequate syringe coverage was significantly higher for all dispensation policies compared to per visit limited one‐for‐one exchange. Using propensity scoring methods, we compared syringe coverage by dispensation policies while controlling for client‐level differences. Providing additional syringes above one‐for‐one exchange (50% versus 38%, P = 0.009) and unlimited exchange (42% versus 27%, P = 0.05) generally resulted in more clients having adequate syringe coverage compared to one‐for‐one exchange and per visit limits.

Conclusion  Providing less restrictive syringe dispensation is associated with increased prevalence of adequate syringe coverage among clients. SEPs should adopt syringe dispensation policies that provide IDUs sufficient syringes to attain adequate syringe coverage.
Effect of structure of a tropical pasture on ingestive behaviour, digestibility of diet and daily intake by grazing cattle
Authors: Boval M. , Fanchone A. , Archimède H. , Gibb M. J.
Published: February 2007

The effect of the structure of a tropical pasture, based on Dichanthium spp., on the ingestive behaviour, in vivo digestibility of the diet and herbage intake by eight Creole tethered heifers was studied. Two levels of nitrogen fertilizer (0 and 50 kg ha−1) were applied to plots after each grazing cycle and there were 28 d between each of the three grazing cycles. Four heifers grazed individual subplots daily on each plot for 14 d in each of the successive grazing cycles. Simultaneous measurements of bite depth, bite mass, biting rate, short‐term intake rate and daily grazing time were made in two 4‐d periods at the end of each 14‐d period. The in vivo organic matter digestibility (OMD) and daily herbage organic matter intake (OMI, expressed on a kg LW0·75 basis) were also measured at the same times. Relationships among pasture characteristics and ingestive behaviour were similar to those reported in other short‐term studies: pasture height was highly correlated with bite depth, bite mass and biting rate (r = 0·91, r =0·79 and r = −0·68, respectively, P < 0·001). Pasture variables had lower correlations with grazing time and short‐term intake rate than with bite depth, bite mass and biting rate. Pasture structure was more highly correlated with OMD than OMI: leaf mass and length and also the extended tiller length were highly correlated with OMD (r = 0·77, r = 0·76 and r = 0·72, respectively, P < 0·001) whereas the crude protein concentration of the herbage was correlated with OMI and digestible OMI (r = 0·50 and r = 0·69, respectively, P < 0·001). Ingestive behaviour variables, as well as OMD, were correlated more with pasture characteristics than was OMI.
Inter‐ and intra‐population genetic variation for leaf:stem ratio in landraces and varieties of lucerne
Authors: Annicchiarico P.
Published: February 2007

A comparison was made of landrace vs. variety inter‐ and intra‐population genetic variation for leaf:stem ratio in lucerne and investigated its relationship with forage yield and other characters. Very early‐flowering genotypes were excluded from the assessment to limit the impact of maturity stage on the variation in leaf:stem ratio. The evaluation was performed on a summer harvest of 390 genotypes belonging to ten landraces from northern Italy and to six well‐performing varieties, and on nineteen clones of a single genotype which were used to estimate the environmental variance. Landrace and variety groups did not differ in mean leaf:stem ratio. Variation for this trait was significant among varieties (P < 0·05) but not among landraces. Within‐population variation was significant for both germplasm groups (P < 0·01), being somewhat larger in landraces. The estimated within‐population variance component largely exceeded the among‐population variance component within varieties. Higher leaf:stem ratios were mainly associated with shorter and thinner main stems in genotypes and populations, and showed a modest inverse correlation with forage yield. The results highlight the importance of landrace germplasm and the paramount importance of selection within populations to identify parent material with a high leaf:stem ratio.
Morphological characteristics and nutritive value of some grass species in an arid ecosystem
Authors: Saini M. L. , Jain P. , Joshi U. N.
Published: February 2007

An experiment was conducted on four genotypes of Cenchrus ciliaris, two genotypes of C. setigerus and one genotype each of Panicum maximum, P. antidotale and Lasirus sindicus grasses at CCS Haryana Agricultural University, Haryana, India in 2003 and 2004. Two cuts were taken in the months of September and November in each year. Measurements were made of seven morphological characteristics and the nutritive value of the grasses. The total green fodder yield was highest in C. ciliaris cv. IGFRI in 2003 and in C. ciliaris cv. CAZRI 75 in 2004. Total dry matter (DM) yield was highest in P. maximum cv. IGFRI and C. ciliaris cv. CAZRI 75 in 2003 and 2004, respectively. Crude protein and digestible DM yields were highest in C. ciliaris cv. CAZRI 75. It was concluded that C. ciliaris cv. CAZRI 75 can be recommended as the one with the most potential among the studied grasses for use in the arid regions of south‐west Haryana, India.
European Union Adopts Regulation on Compulsory Licensing of Pharmaceutical Products for Export
Authors: Cornides Jakob
Published: February 2007

On 17 May 2006, the European Union adopted new legislation implementing the World Trade Organization (WTO) General Council Decision of 30 August 2003: Council Regulation 816/2006. This regulation aims to reflect faithfully the compromise negotiated at the WTO without creating an unnecessary burden for importing countries. Not all expectations articulated by the non‐governmental organization community could be met. Yet, criticism against the regulation seems premature: the value of compulsory licensing rules does not depend on the number of compulsory licences granted, but on the pressure such provisions exert on patentees to make their product available at a reasonable price.
EXECUTION BY LETHAL INJECTION, EUTHANASIA, ORGAN‐DONATION AND THE PROPER GOALS OF MEDICINE
Authors: VARELIUS JUKKA
Published: February 2007

In a recent issue of this journal, David Silver and Gerald Dworkin discuss the physicians' role in execution by lethal injection. Dworkin concludes that discussion by stating that, at that point, he is unable to think of an acceptable set of moral principles to support the view that it is illegitimate for physicians to participate in execution by lethal injection that would not rule out certain other plausible moral judgements, namely that euthanasia is under certain conditions legitimate and that organ‐donation surgery is sometimes permissible. This article draws attention to some problems in the views of Silver and Dworkin and suggests moral principles which support the three moral views just mentioned.
Sorted: the revival of Pitney Bowes
Authors: Crainer Stuart
Published: February 2007

With 80 per cent market share, Pitney Bowes had little incentive to reinvent itself. Yet, over the last decade the American company has undergone a carefully calibrated transformation. Stuart Crainer provides the inside story on the evolution of the mail giant.
Demanding better supply management
Authors: Niezen Carlos , Weller Wulf , Deringer Heidi
Published: February 2007

Supply management isn't what it used to be, according to Carlos Niezen, Wulf Weller and Heidi Deringer, Savvy supply management can increase shareholder value, but only if you reinvent the concept for a new century.
Modelling service
Authors: Evans Cliff
Published: February 2007

Changes to the business environment are forcing companies to look for ways to become significantly more efficient and more accessible to their customers, suppliers, and shareholders. Cliff Evans thinks the service‐based operating model is the solution.
Optimal prepayment of Dutch mortgages*
Authors: Kuijpers Bart H. M. , Schotman Peter C.
Published: February 2007

Valuation of the prepayment option in Dutch mortgages is complicated. In the Netherlands, mortgagors are not allowed to prepay the full mortgage loan without a compensating penalty. Only a limited amount of the initial mortgage loan can be prepaid penalty‐free. We introduce a general model formulation for the valuation of limited callable mortgages, based on binomial trees. This model can be used for determining both the optimal prepayment strategy and the value of embedded prepayment options. For some mortgage types the prepayment option can be valued exactly, whereas other types require approximative methods for efficient valuation. The heuristic we propose here determines the prepayment option value efficiently and accurately for general mortgage types.
Disconnecting graphs by removing vertices: a polyhedral approach
Authors: Oosten Maarten , Rutten Jeroen H. G. C. , Spieksma Frits C. R.
Published: February 2007

In this paper, we consider the problem of disconnecting a graph by removing as few vertices as possible, such that no component of the disconnected graph has more than a given number of vertices. We give applications of this problem, present a formulation for it, and describe some polyhedral results. Furthermore, we establish ties with other polytopes and show how these relations can be used to obtain facets of our polytope. Finally, we give some computational results.
State space models for time series with patches of unusual observations
Authors: Penzer Jeremy
Published: February 2007

Abstract. An alternative to leave‐k‐out diagnostics for detecting patches of outlying points in time series is developed. We propose that unusual behaviour should be modelled by the addition of shocks. By including shocks in the transition equation of a state space model, we admit the possibility of a persistent change associated with a patch of outliers. Persistent change may take the form of a level shift or a change in seasonal pattern. We provide an efficient mechanism for computing diagnostic statistics associated with the addition ofkshocks using a simple adaptation of the Kalman filter. Statistics for detecting unspecified patterns of shocks and an interpretation of the output of the associated smoothing algorithm are derived. Illustrations using real series are given.
CHARACTERIZATION OF COURNOT EQUILIBRIA IN A MARKET WITH NETWORK EFFECTS*
Authors: KWON NAMHOON
Published: February 2007

Market equilibria are difficult to describe in markets with network effects because they often involve an upward sloping demand curve and/or multiple equilibria. In the framework of symmetric Cournot oligopoly, I investigate for a minimal set of conditions and thus extend the standard equilibrium analysis by Amir (Games and Economic Behavior, Vol. 15 (1996), pp. 132–148) and Amir and Lambson (Review of Economic Studies, Vol. 67 (2000), pp. 235–254) to these kinds of markets.
R&D INSTITUTIONAL ARRANGEMENTS: START‐UP VENTURES VERSUS INTERNAL LAB*
Authors: DIX MANFRED , GANDELMAN NÉSTOR
Published: February 2007

Why do firms sometimes choose to undertake their R&D by financing start‐up companies, while other times they do it in their internal labs? We present a model where the choice of R&D is driven by information asymmetries on the quality of the project between the corporate venture capitalist and the idea owner. In an incomplete information environment, higher‐quality projects are more likely to be developed by start‐up firms, while low‐quality ones are exploited internally. Also, two types of risk are examined, intrinsic quality risk and external shock risk. Riskier project quality and more difficult project monitoring make a project more likely to be developed as a new venture. Finally, the model is able to show why corporate lab scientists get most of their compensation as a fixed salary, while idea owner entrepreneurs working for start‐up companies have a profit‐sharing agreement.
INSTITUTIONAL DEVELOPMENT: SKILL TRANSFERENCE THROUGH A REVERSAL OF ‘HUMAN CAPITAL FLIGHT’ OR TECHNICAL ASSISTANCE
Authors: Ul Haque Nadeem , Ali Khan M.
Published: February 2007

Abstract.  We examine the issue of technical assistance versus brain drain repatriation as alternative strategies for transferring scarce skills to a skill‐poor economy. Technical assistance relies mainly on expatriate skills and labour from the host country, while brain drain repatriation seeks to effect a return of skills that might have been lost in migration. We show that, even in the simplest setting with imperfect information, a surprisingly rich menu of responses is obtained.
SPECIALIZATION, THE INTERMEDIATE NATURE OF TRADED PRODUCTS AND THE MYTH OF IMPORT DRIVEN WAGE INEQUALITY IN THE UNITED STATES
Authors: Tombazos Christis G.
Published: February 2007

Abstract.  Using a model that recognises the prevalent cross‐country specialization in production and the intermediate nature of all traded products, I investigate the effect of observed trends in the prices of ordinary intermediate and semi‐final imports on the expanding wage differential between skilled and unskilled labour in the USA. Contrary to widely accepted stylised facts, my results suggest that decreases in import prices increase both wage rates, while compressing their differential. Sources of wage dispersion are, however, found in skill‐biased economy‐wide dynamic processes of capital accumulation and technical change.