bluuebunny/crossref_metadata_2025 huggingface dataset:
WEAK AND STRONG SUSTAINABILITY, ENVIRONMENTAL CONSERVATION AND ECONOMIC GROWTH
Authors: HEDIGER WERNER
Published: August 2010

ABSTRACT. To investigate the role of explicit and implicit assumptions in different models of weak and strong sustain‐ability, the Solow/Hartwick model of intergenerational equity with nonrenewable resources is gradually extended to include renewable resources, endogenous technical progress, and stock pollution. This reveals the fundamental role of endogenous technical progress for sustainable development, the inconsistency of implicit sustainability assumptions in various models, as well as the existence of a Hartwick rule for Daly's steady‐state economy. Moreover, it shows that the concepts of Solow sustainability and strong sustainability coincide as a special case of weak sustainability. The latter integrates economic and environmental concerns and aims at maintaining the welfare potential of an economy over time. It does not rule out economic growth by assumption. Rather, the analysis shows that environmental conservation and economic growth can be compatible with each other, without jeopardizing social welfare. Finally, the analysis shows that the discussion of sustain‐ability models cannot be restricted to the explicit differences that are usually pointed out by their authors and commentators. Rather, implicit assumptions must be made explicit.
MODELING A RIGHTS‐BASED APPROACH FOR MANAGING HABITAT IMPACTS OF FISHERIES
Authors: HOLLAND DANIEL S. , SCHNIER KURT E.
Published: August 2010

ABSTRACT. Limiting adverse consequences of fishing on essential fish habitat has emerged as a key fishery management objective. The conventional approach to providing habitat protection is to create MPAs or marine reserves that prohibit all or certain types of fishing in specific areas. However, there may be more cost‐effective and flexible ways to provide habitat protection. We propose an individual habitat quota (IHQ) system for habitat conservation that would utilize economic incentives to achieve habitat conservation goals cost‐effectively. Individual quotas of habitat impact units (HIU) would be distributed to fishers with an aggregate quota set to maintain a target habitat “stock.” HIU use would be based on a proxy for marginal habitat damage. We use a dynamic, explicitly spatial fishery and habitat simulation model to explore how such a system might work. We examine how outcomes are affected by spatial heterogeneity in the fishery and the scale of habitat regulation. We find that the IHQ system is a highly cost‐effective means of ensuring a given level of habitat protection, but that spatial heterogeneity and the scale of regulation can have significant effects on the distribution of habitat protection.
MODELING THE SPATIAL DISTRIBUTION OF MINERAL DEPOSITS USING NEURAL NETWORKS
Authors: SKABAR ANDREW
Published: August 2010

ABSTRACT. In the context of Geographic Information Systems (GIS), mineral potential mapping can be seen as a process whereby a set of input maps, each representing a distinct geoscientific variable, are combined to produce a single map which ranks areas according to their potential to host deposits of a particular type. However, unlike many spatial classification tasks, the objective is not to assign a pixel to some class, but to assign to each pixel a continuous value representing its mineralization potential. Logistic regression provides one method of modeling conditional probabilities on data in which the target values are binary, e.g., deposit present/deposit absent; however, logistic regression limits the output to be a logistic transformation of the inputs and hence may not be able to capture complex relationships among the input variables. This paper reports on the application of multilayer perceptrons (MLPs) to mapping reef gold mineralization potential in the Castlemaine region of Victoria, Australia. We show that the ability of MLPs to predict the presence of hold‐out test deposits is significantly better than that for logistic regression. We also show that a Bayesian learning approach can be used to automatically select an appropriate value for the weight regularization coefficient without the need of using a cross‐validation procedure. This means that all available data can be used for weight optimization, thus eliminating any sensitivity of the final map to the particular training/validation set partition used.

This paper was presented at the 2004 Research Modeling Association World Conference on Natural Resource Modeling in Melbourne, Australia.
JOINTLY‐DETERMINED ECOLOGICAL THRESHOLDS AND ECONOMIC TRADE‐OFFS IN WILDLIFE DISEASE MANAGEMENT
Authors: FENICHEL ELI P. , HORAN RICHARD D.
Published: August 2010

ABSTRACT. We investigate wildlife disease management, in a bioeconomic framework, when the wildlife host is valuable and disease transmission is density‐dependent. Disease prevalence is reduced in density‐dependent models whenever the population is harvested below a host‐density threshold a threshold population density below which disease prevalence declines and above which a disease becomes epidemic. In conventional models, the threshold is an exogenous function of disease parameters. We consider this case and find a steady state with positive disease prevalence to be optimal. Next, we consider a case in which disease dynamics are affected by both population controls and changes in human‐environmental interactions. The host‐density threshold is endogenous in this case. That is, the manager does not simply manage the population relative to the threshold, but rather manages both the population and the threshold. The optimal threshold depends on the economic and ecological trade‐offs arising from the jointly‐determined system. Accounting for this endogene‐ity can lead to reduced disease prevalence rates and higher population levels. Additionally, we show that ecological parameters that may be unimportant in conventional models that do not account for the endogeneity of the host‐density threshold are potentially important when host density threshold is recognized as endogenous.
APPLICATION OF BAYESIAN STATISTICAL INFERENCE AND DECISION THEORY TO A FUNDAMENTAL PROBLEM IN NATURAL RESOURCE SCIENCE: THE ADAPTIVE MANAGEMENT OF AN ENDANGERED SPECIES
Authors: STAUFFER HOWARD B.
Published: August 2010

Abstract A fundamental problem of interest to contemporary natural resource scientists is that of assessing whether a critical population parameter such as population proportion p has been maintained above (or below) a specified critical threshold level pc. This problem has been traditionally analyzed using frequentist estimation of parameters with confidence intervals or frequentist hypothesis testing. Bayesian statistical analysis provides an alternative approach that has many advantages. It has a more intuitive interpretation, providing probability assessments of parameters. It provides the Bayesian logic of “if (data), then probability (parameters)” rather than the frequentist logic of “if (parameters), then probability (data).” It provides a sequential, cumulative, scientific approach to analysis, using prior information and reassessing the probability distribution of parameters for adaptive management decision making. It has been integrated with decision theory and provides estimates of risk. Natural resource scientists have the opportunity of using Bayesian statistical analysis to their advantage now that this alternative approach to statistical inference has become practical and accessible.
ISOMETRIC AND ALLOMETRIC RELATIONSHIPS BETWEEN LARGE AND SMALL‐SCALE TREE SPACING STUDIES
Authors: STRUB MIKE R. , AMATEIS RALPH L.
Published: August 2010

AbstractBasic differences in the relationship between diameter and height have been observed in small and large trees. Small trees (less than 5 m) have little danger of buckling under their own weight, and diameter is proportional to height. Large trees (greater than 5 m) are at risk of buckling under their own weight and are subject to damage from ice and wind. For large trees, diameter cubed is proportional to height squared. This relationship is suggested by the physics of limits to height of cylinders before they buckle under their own weight and has been shown to hold for large trees. Data from large‐scale spacing studies are compared with data from one‐sixteenth scale small spacing studies to determine the validity of this theory. The impact of scaled spacing on scaled diameters at equivalent scaled heights is examined. Results suggest that trees grown at small scales can be “scaled up” to reflect isometric and allometric relationships of trees grown at large scales.
SPATIAL EFFECTS IN AN INDIVIDUAL‐BASED MODEL OF PRODUCER–HERBIVORE INTERACTION
Authors: CHIVERS W.J. , GLADSTONE W. , HERBERT R.D.
Published: August 2010

Abstract In this paper, we describe an individual‐based model of the interaction between a producer and herbivore species. The interaction occurs in a 2‐dimensional matrix of individual cells. The producer organism grows in the cells and the herbivores move between the cells, towards areas of high concentration of producer. Herbivores may die of starvation or they may reproduce asexually. The model is not built to represent a specific existing system but is a parsimonious generalized model of producer–herbivore interaction designed to test spatial effects.

Although the model algorithm is kept simple—the herbivores have no learning or social behavior and have a minimal foraging strategy—the model displays some characteristics of real systems such as metapopulation behavior. We find significant effects on the herbivore and producer populations of the maximum move distance per step of the herbivores, the shape of the two‐dimensional matrix, the quality of a corridor between patches habitable by the herbivores, and edge effects with fuzzy edges. The behavior of the model is comparable with empirical observations found in the literature, and we suggest that this simple model may be used to investigate the mechanism of these real effects.
MODELING CLIMATE CHANGE AND THE EFFECT ON THE NORWEGIAN SALMON FARMING INDUSTRY
Authors: LORENTZEN TORBJØRN
Published: August 2010

Abstract Global warming is expected to affect the ecosystem in the Northeast Atlantic, and substantial changes will also affect the aquaculture industry. Farming of salmon and trout is the biggest aquaculture industry in Norway, with an export value of about 3 billion US dollars in 2007. The objective of the paper is to analyze the potential economic effect a general increase in sea temperature can have on the Norwegian salmon aquaculture industry. The assessment of the economic impact of global warming is made possible by estimating a growth function, which explicitly includes sea water temperature. The analysis compares the economic effect of a climate change on fish farming plants in the south and the north of Norway. The scenarios are based on a model with monthly seasonal variation in temperature.
OPTIMAL HARVESTING OF A SPATIALLY EXPLICIT FISHERY MODEL
Authors: DING WANDI , LENHART SUZANNE
Published: August 2010

Abstract We consider an optimal fishery harvesting problem using a spatially explicit model with a semilinear elliptic PDE, Dirichlet boundary conditions, and logistic population growth. We consider two objective functionals: maximizing the yield and minimizing the cost or the variation in the fishing effort (control). Existence, necessary conditions, and uniqueness for the optimal harvesting control for both cases are established. Results for maximizing the yield with Neumann (no‐flux) boundary conditions are also given. The optimal control when minimizing the variation is characterized by a variational inequality instead of the usual algebraic characterization, which involves the solutions of an optimality system of nonlinear elliptic partial differential equations. Numerical examples are given to illustrate the results.
STOCHASTIC MODEL OF LAKE SYSTEM INVASION AND ITS OPTIMAL CONTROL: NEURODYNAMIC PROGRAMMING AS A SOLUTION METHOD
Authors: POTAPOV ALEX
Published: August 2010

AbstractWe develop a stochastic model for the process of spread of an aquatic invader in a lake system. The invader is transported along with recreation boats, and treatment of boats allows one to control the invader spread. Optimization of invasion and control costs leads to a dynamic programming problem. However, standard stochastic dynamic programming (SDP) algorithms allow us to solve the problem for at most 13–14 lakes, which is significantly less than the size of systems arising in applications. We have developed a new technique, which is based upon the ideas of reinforcement learning and neurodynamic programming. This approach allows us to obtain approximate but reasonable control policy for essentially greater lake systems. The resulting numerical technique is comparatively easy to implement, and it can be applied to other spatially extended optimal control problems as well.
OPTIMAL DYNAMIC HARVEST OF A MOBILE RENEWABLE RESOURCE
Authors: JOSHI HEM RAJ , HERRERA GUILLERMO E. , LENHART SUZANNE , NEUBERT MICHAEL G.
Published: August 2010

Abstract We present a mathematical model for the growth, movement, and harvesting of a renewable resource, and characterize the spatiotemporal distribution of harvest effort which maximizes the present value of harvest (yield) over a finite time horizon. We derive the optimality system for this model and show that the yield‐maximizing solution often includes one or more no‐take reserves that change in size over time. We explore how the results change with varying parameter values. The results inform ongoing debate about the use of reserves, and are increasingly relevant as technology enables enforcement of spatially structured harvest constraints.
Histone H3 Thr-3 Phosphorylation by Haspin Positions Aurora B at Centromeres in Mitosis
Authors: Wang Fangwei , Dai Jun , Daum John R. , Niedzialkowska Ewa , Banerjee Budhaditya , Stukenberg P. Todd , Gorbsky Gary J. , Higgins Jonathan M. G.
Published: August 2010

Location, Location, Location

Cell division is orchestrated by a complex signaling pathway that ensures the correct segregation of newly replicated chromosomes to the two daughter cells. The pathway is controlled in part by restricting the activity of critical regulators to specific subcellular locations. For example, the chromosomal passenger complex (CPC) is recruited to chromosomes during mitosis where it oversees kinetochore activity and cytokinesis (see Perspective by

Musacchio

).

Wang
et al.

(p.
231
, published online 12 August),

Kelly
et al.

(p.
235
, published online 12 August), and

Yamagishi
et al.

(p.
239
) now show that the phosphorylation of the chromatin protein, histone H3, acts to bring the CPC to chromosomes, thereby activating its aurora B kinase subunit. The Survivin subunit of CPC binds specifically to phosphorylated H3, with the phosphorylation at centromeres being carried out by the mitosis-specific kinase, haspin. Furthermore, Bub1 phosphorylation of histone H2A recruits shugoshin, a centromeric CPC adapter. Thus, these two histone marks in combination define the inner centromere.
Detection of a Trailing (L5) Neptune Trojan
Authors: Sheppard Scott S. , Trujillo Chadwick A.
Published: August 2010

An asteroid follows the orbit of the planet Neptune in a region of gravitational stability.
Role of imaging in the diagnosis of acute bacterial meningitis and its complications
Authors: Hughes D C , Raghavan A , Mordekar S R , Griffiths P D , Connolly D J A
Published: August 2010

Acute bacterial meningitis is a common neurological emergency and a leading cause of death and neurological disability worldwide. Diagnosis is based on clinical and microbiological findings with neuroimaging in the form of CT reserved for those with specific adverse clinical features or when an underlying cause such as mastoiditis is suspected. MRI is extremely useful for detecting and monitoring the complications of meningitis. These can be remembered by the mnemonic HACTIVE (hydrocephalus, abscess, cerebritis/cranial nerve lesion, thrombosis, infarct, ventriculitis/vasculopathy and extra-axial collection). Diffusion weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) are useful to distinguish abscess from other ring enhancing lesions.
MINIMAL FLAVOR CONSTRAINTS FOR TECHNICOLOR
Authors: FUKANO HIDENORI S. , SANNINO FRANCESCO
Published: August 2010

We analyze the constraints on the the vacuum polarization of the Standard Model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and masses of the lightest spin-one resonances. Our analysis is applicable to any four and higher-dimensional extension of the Standard Model reducing to models of dynamical electroweak symmetry breaking.
EVOLVING SPHERES OF SHEAR-FREE ANISOTROPIC FLUID
Authors: IVANOV B. V.
Published: August 2010

The fluid models mentioned in the title are studied in a modified approach, based on two formulas for the mass function. All characteristics of the fluid are expressed through a master potential, satisfying an ordinary second-order differential equation. Different constraints are imposed on this core of relations, finding new solutions and deriving the classical results for perfect fluids as particular cases. All charged anisotropic solutions, all conformally flat and all uniform density solutions are found. A large class of solutions with linear equation among the two pressures is derived, including the case of vanishing tangential pressure. The mechanism responsible for the appearance of equation of state is elucidated.
HERTZ VECTORS AND THE ELECTROMAGNETIC-QUANTUM EQUATIONS
Authors: KOUZAEV GUENNADI A.
Published: August 2010

In this letter, a new form of electromagnetic-quantum equations is proposed. The electric and magnetic potentials are expressed through a single Hertz vector, and the systems of quantum and Maxwell equations are transformed into more compact integro-differential ones. These new forms are given for the Schrödinger, Pauli, Dirac and Klein–Gordon equations, and a practical way to calculate them by available software tools is considered.
SIZE-INDUCED PHASE TRANSITION IN BaTiO3 NANOCERAMICS DESCRIBED BY NANO-DOMAINS AND LONG-RANGE INTERACTION
Authors: FANG C. , ZHOU D. X. , GONG S. P.
Published: August 2010

The size effect of nano-grain BaTiO 3 ceramics has been studied in this paper. We assume that the surface charge does not fully compensate long-range Coulomb interaction, so that 180 degree nano-domains still exists in small BaTiO 3 particles. We have calculated the long-range interaction in BaTiO 3 nanocrystals with 180 degree nano-domains, and obtained the relationship between grain size and domain size. The relation between transition temperature and grain size is also obtained by incorporating the domain-wall energy into the Landau–Ginzburg free-energy density. The results show that with decreasing grain size the transition temperature of cubic-tetragonal phase decreases, while those of tetragonal-orthorhombic and orthorhombic-rhombohedral phases increase. Our model predicts that with further reduction of grain size, the structures of ferroelectric phase becomes unstable and gradually disappears, leaving only one stable structure of cubic phase. In addition, an interesting conclusion is that a quadruple phase point exists in the phase diagram of the transition temperature versus grain size. The results are compared with experimental data.
A STUDY ON THE MAGNETIC PROPERTIES IN NITROGEN-DOPED ZnO USING FIRST PRINCIPLES
Authors: SHI LI-BIN , JIN JIAN-WEI , XU CUI-YAN
Published: August 2010

Theoretical calculation based on density function theory (DFT) and generalized gradient approximation (GGA) has been carried out in studying the magnetic properties of nitrogen-doped ZnO . The results show that ferromagnetism (FM) coupling between N atoms is more stable for the majority of 11 geometrically distinct configurations, and N atoms in ZnO have a clear clustering tendency. In addition, the formation and ionization energy of native defects in ZnO is analyzed and discussed. The effect of native defects on FM properties of nitrogen-doped ZnO has also been investigated. It is found that FM state is more favored than the AFM state in the presence of zinc vacancy or oxygen interstitial. In the paper, we also analyze strain effect on FM of nitrogen-doped ZnO .
COCOMAT DESIGN AND ANALYSIS GUIDELINES FOR CFRP-STIFFENED PANELS IN BUCKLING AND POSTBUCKLING
Authors: GHILAI GILA , FELDMAN ESTHER , DAVID ADRIAN
Published: August 2010

One of the most important goals of the COCOMAT EU R&D project was the generation of a formulated set of guidelines which could be applied when buckling or postbuckling of CFRP-stiffened panels was considered. In this paper, issues of concern for composite materials are addressed, such as prediction of damage onset and propagation of defects during buckling and postbuckling, under static and cyclic loading. The design and analysis guidelines are the result of good cooperation between partners from the industry, universities and research centers, and are based on extensive theoretical and experimental research performed within the COCOMAT project. The analysis guidelines cover FE types and meshing, damage mechanisms, degradation models, recommendations regarding interface elements in the damage zone and ply failure models. Comparison between various analysis codes is also provided. Lessons learned concerning testing of structures in the buckling regime are presented. The sensitivity of conventional design to damage of various sizes has been investigated, and conclusions are drawn regarding design criteria. Two structural applications are also presented, where some of the above-mentioned guidelines were implemented at Israel Aerospace Industries (IAI).
Electrochemical Investigation of Thin PANI Film onto Insulating Substrate Using Scanning Electrochemical Microscopy
Authors: Ghilane Jalal , Martin Pascal , Janin Marion , Randriamahazaka Hyacinthe , Hapiot Philippe , Lacroix Jean Christophe
Published: August 2010

Electrochemical investigation of conducting polymer, polyaniline (PANI), deposited on insulating substrates was achieved. This study was performed through the reaction with a series of electrogenerated mediators at a microelectrode operating in the configuration of a scanning electrochemical microscope (SECM). The method proves to be a convenient tool for investigating redox properties of the electroactive materials onto insulating substrates and the occurrence of electron transfer within the modified substrate. The SECM results demonstrate the possibility of the regeneration of the mediator at the modified surface even if the used substrate is an insulator. The regeneration rate depends on the standard redox potential of the mediator, on the switching potential of the polymer and on its initial oxidation state. In addition, the obtained data could be analyzed through the construction of the steady state voltammograms allowing the extraction of the electrochemical properties of the thin organic layer deposited onto insulating surface.
Bifidobacterium bifidum reduces apoptosis in the intestinal epithelium in necrotizing enterocolitis
Authors: Khailova Ludmila , Mount Patrick Sarah K. , Arganbright Kelly M. , Halpern Melissa D. , Kinouchi Toshi , Dvorak Bohuslav
Published: August 2010

Necrotizing enterocolitis (NEC) is a devastating intestinal disease of neonates, and clinical studies suggest the beneficial effect of probiotics in NEC prevention. Recently, we have shown that administration of Bifidobacterium bifidum protects against NEC in a rat model. Intestinal apoptosis can be suppressed by activation of cyclooxygenase-2 (COX-2) and increased production of prostaglandin E2(PGE2). The present study investigates the effect of B. bifidum on intestinal apoptosis in the rat NEC model and in an intestinal epithelial cell line (IEC-6), as a mechanism of protection against mucosal injury. Premature rats were divided into the following three groups: dam fed, hand fed with formula (NEC), or hand fed with formula supplemented with B. bifidum (NEC + B. bifidum ). Intestinal Toll-like receptor-2 (TLR-2), COX-2, PGE2, and apoptotic regulators were measured. The effect of B. bifidum was verified in IEC-6 cells using a model of cytokine-induced apoptosis. Administration of B. bifidum increased expression of TLR-2, COX-2, and PGE2and significantly reduced apoptosis in the intestinal epithelium of both in vivo and in vitro models. The Bax-to-Bcl-w ratio was shifted toward cell survival, and the number of cleaved caspase-3 positive cells was markedly decreased in B. bifidum -treated rats. Experiments in IEC-6 cells showed anti-apoptotic effect of B. bifidum . Inhibition of COX-2 signaling blocked the protective effect of B. bifidum treatment in both in vivo and in vitro models. In conclusion, oral administration of B. bifidum activates TLR-2 in the intestinal epithelium. B. bifidum increases expression of COX-2, which leads to higher production of PGE2in the ileum and protects against intestinal apoptosis associated with NEC. This study indicates the ability of B. bifidum to downregulate apoptosis in the rat NEC model and in IEC-6 cells by a COX-2-dependent matter and suggests a molecular mechanism by which this probiotic reduces mucosal injury and preserves intestinal integrity.
Role of cholinergic neurons in the motor effects of glucagon-like peptide-2 in mouse colon
Authors: Amato Antonella , Rotondo Alessandra , Cinci Lorenzo , Baldassano Sara , Vannucchi Maria Giuliana , Mulè Flavia
Published: August 2010

Glucagon-like peptide-2 (GLP-2) reduces mouse gastric tone and small intestine transit, but its action on large intestine motility is still unknown. The purposes of the present study were 1) to examine the influence of GLP-2 on spontaneous mechanical activity and on neurally evoked responses, by recording intraluminal pressure from mouse isolated colonic segments; 2) to characterize GLP-2 mechanism of action; and 3) to determine the distribution of GLP-2 receptor (GLP-2R) in the mouse colonic muscle coat by immunohistochemistry. Exogenous GLP-2 (0.1–300 nM) induced a concentration-dependent reduction of the spontaneous mechanical activity, which was abolished by the desensitization of GLP-2 receptor or by tetrodotoxin, a voltage-dependent Na+-channel blocker. GLP-2 inhibitory effect was not affected by Nω-nitro-l-arginine methyl ester (a nitric oxide synthase inhibitor), apamin (a blocker of small conductance Ca2+-dependent K+ channels), or [Lys1,Pro2,5,Arg3,4,Tyr6]VIP7–28 (a VIP receptor antagonist), but it was prevented by atropine or pertussis toxin (PTX), a Gi/o protein inhibitor. Proximal colon responses to electrical field stimulation were characterized by nitrergic relaxation, which was followed by cholinergic contraction. GLP-2 reduced only the cholinergic evoked contractions. This effect was almost abolished by GLP-2 receptor desensitization or PTX. GLP-2 failed to affect the contractile responses to exogenous carbachol. GLP-2R immunoreactivity (IR) was detected only in the neuronal cells of both plexuses of the colonic muscle coat. More than 50% of myenteric GLP-2R-IR neurons shared the choline acetyltransferase IR. In conclusion, the activation of GLP-2R located on cholinergic neurons may modulate negatively the colonic spontaneous and electrically evoked contractions through inhibition of acetylcholine release. The effect is mediated by Gi protein.
Venous emptying from the foot: influences of weight bearing, toe curls, electrical stimulation, passive compression, and posture
Authors: Broderick Barry J. , Corley Gavin J. , Quondamatteo Fabio , Breen Paul P. , Serrador Jorge , ÓLaighin Gearóid
Published: August 2010

This study investigated the hemodynamic properties of the plantar venous plexus (PVP), a peripheral venous pump in the human foot, with Doppler ultrasound. We investigated how different ways of introducing mechanical changes vary in effectiveness of displacing blood volume from the PVP. The contribution of the PVP was analyzed during both natural and device-elicited compressions. Natural compressions consisted of weight bearing on the foot and toe curl exercises. Device-elicited compressions consisted of intermittent pneumatic compression (IPC) of the foot and electrically elicited foot muscle contractions. Ten healthy participants had their posterior tibial, peroneal, anterior tibial, and popliteal vein blood flow monitored while performing these natural and device-elicited compressions of the PVP supine and in an upright position. Results indicated that 1) natural compression of the PVP, weight bearing and toe curls, expelled a significantly larger volume of blood than device-elicited PVP compression, IPC and electrical stimulation; 2) there was no difference between the venous volume elicited by weight bearing and by toe curls; 3) expelled venous volume recorded at the popliteal vein under all test conditions was significantly greater than that recorded from the posterior tibial and peroneal veins; 4) there was no significant difference between the volume in the posterior tibial and peroneal veins; 5) ejected venous volume recorded in the upright position was significantly higher than that recorded in the supine position. Our study shows that weight bearing and toe curls make similar contributions to venous emptying of the foot.
Effects of sleep on the cardiovascular and thermoregulatory systems: a possible role for hypocretins
Authors: Schwimmer H. , Stauss H. M. , Abboud F. , Nishino S. , Mignot E. , Zeitzer J. M.
Published: August 2010

Sleep influences the cardiovascular, endocrine, and thermoregulatory systems. Each of these systems may be affected by the activity of hypocretin (orexin)-producing neurons, which are involved in the etiology of narcolepsy. We examined sleep in male rats, either hypocretin neuron-ablated orexin/ataxin-3 transgenic (narcoleptic) rats or their wild-type littermates. We simultaneously monitored electroencephalographic and electromyographic activity, core body temperature, tail temperature, blood pressure, electrocardiographic activity, and locomotion. We analyzed the daily patterns of these variables, parsing sleep and circadian components and changes between states of sleep. We also analyzed the baroreceptor reflex. Our results show that while core temperature and heart rate are affected by both sleep and time of day, blood pressure is mostly affected by sleep. As expected, we found that both blood pressure and heart rate were acutely affected by sleep state transitions in both genotypes. Interestingly, hypocretin neuron-ablated rats have significantly lower systolic and diastolic blood pressure during all sleep stages (non-rapid eye movement, rapid eye movement) and while awake (quiet, active). Thus, while hypocretins are critical for the normal temporal structure of sleep and wakefulness, they also appear to be important in regulating baseline blood pressure and possibly in modulating the effects of sleep on blood pressure.
Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans
Authors: Wingo Jonathan E. , Low David A. , Keller David M. , Brothers R. Matthew , Shibasaki Manabu , Crandall Craig G.
Published: August 2010

Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdialysis membranes were placed in posterior forearm skin not covered by the suit to manipulate skin blood flow using vasoactive agents. Each site was instrumented for control of local temperature and measurement of local SR (capacitance hygrometry) and skin blood flow (laser-Doppler flowmetry). In protocol I, two sites received norepinephrine to reduce skin blood flow, while two sites received Ringer solution (control). All sites were maintained at 34°C. In protocol II, all sites received 28 mM sodium nitroprusside to equalize skin blood flow between sites before local cooling to 20°C (2 sites) or maintenance at 34°C (2 sites). In both protocols, individuals were then passively heated to increase core temperature ∼1°C. Both decreased skin blood flow and decreased local temperature attenuated the slope of the SR to mean body temperature relationship (2.0 ± 1.2 vs. 1.0 ± 0.7 mg·cm−2·min−1·°C−1 for the effect of decreased skin blood flow, P = 0.01; 1.2 ± 0.9 vs. 0.07 ± 0.05 mg·cm−2·min−1·°C−1 for the effect of decreased local temperature, P = 0.02). Furthermore, local cooling delayed the onset of sweating (mean body temperature of 37.5 ± 0.4 vs. 37.6 ± 0.4°C, P = 0.03). These data demonstrate that local cooling attenuates sweating by independent effects of decreased skin blood flow and decreased local skin temperature.
Endogenously Decreasing Tissue n-6/n-3 Fatty Acid Ratio Reduces Atherosclerotic Lesions in
Apolipoprotein E
–Deficient Mice by Inhibiting Systemic and Vascular Inflammation
Authors: Wan Jian-Bo , Huang Li-Li , Rong Rong , Tan Rui , Wang Jingdong , Kang Jing X.
Published: August 2010

Objective—

To use the
fat-1
transgenic mouse model to determine the role of tissue n-6/n-3 fatty acid ratio in atherosclerotic plaque formation. Although it has been suggested that a low ratio of n-6/n-3 polyunsaturated fatty acids (PUFAs) is more desirable in reducing the risk of atherosclerotic cardiovascular disease, the role of tissue n-6/n-3 fatty acid ratio in atherosclerosis has not been sufficiently tested in a well-controlled experimental system. The
fat-1
transgenic mouse model, expressing an n-3 fatty acid desaturase, is capable of producing n-3 PUFAs from n-6 PUFAs and thereby has a ratio of n-6/n-3 fatty acids close to 1:1 in tissues and organs.

Methods and Results—

To generate apolipoprotein E–deficient plus
fat-1
transgenic mice (
apoE
−/−
/
fat-1
), we crossed heterozygous
fat-1
mice with
apoE
−/−
mice. After 14 weeks of a Western-type diet rich in n-6 PUFAs, the
apoE
−/−
/
fat-1
mice showed a lower ratio of n-6/n-3 fatty acids than the
apoE
−/−
mice in all organs and tissues tested. The aortic lesion area in
apoE
−/−
/
fat-1
mice was significantly reduced when compared with that of
apoE
−/−
littermates (7.14±0.54% versus 13.49±1.61%). There were no differences in plasma cholesterol or high- and low-density lipoprotein levels between the 2 groups, except for a higher triglyceride level in the
apoE
−/−
/
fat-1
mice. A significant reduction of interleukin 6 and prostaglandin E
2
in both plasma and aorta culture medium was observed in
apoE
−/−
/
fat-1
mice. RT-PCR analysis also indicated that the expression of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, interleukin 6, and cyclooxygenase-2 was lower in the aortas and the circulating monocytes from
apoE
−/−
/
fat-1
mice. In addition, the expression of nuclear factor κB/p65 in the aorta and the recruitment of macrophages into atherosclerotic plaques were reduced in
apoE
−/−
/
fat-1
mice, compared with
apoE
−/−
mice.

Conclusion—

To our knowledge, this is the first study to provide direct evidence for the role of tissue n-6/n-3 ratio in atherosclerosis using the
fat-1
transgenic mouse model. Our findings demonstrate that a decreased n-6/n-3 fatty acid ratio reduces atherosclerotic lesions in
apoE
−/−
mice. This protective effect may be attributed to the antiinflammatory properties of n-3 fatty acids, rather than their lipid-lowering effect.
The Transcription Factor GATA-6 Regulates Pathological Cardiac Hypertrophy
Authors: van Berlo Jop H. , Elrod John W. , van den Hoogenhof Maarten M.G. , York Allen J. , Aronow Bruce J. , Duncan Stephen A. , Molkentin Jeffery D.
Published: August 2010

Rationale:

The transcriptional code that programs maladaptive cardiac hypertrophy involves the zinc finger–containing DNA binding factor GATA-4. The highly related transcription factor GATA-6 is also expressed in the adult heart, although its role in controlling the hypertrophic program is unknown.

Objective:

To determine the role of GATA-6 in cardiac hypertrophy and homeostasis.

Methods and Results:

Here, we performed a cardiomyocyte-specific conditional gene targeting approach for
Gata6
, as well as a transgenic approach to overexpress GATA-6 in the mouse heart. Deletion of
Gata6-loxP
with
Nkx2.5-cre
produced late embryonic lethality with heart defects, whereas deletion with β-myosin heavy chain-cre (βMHC-cre) produced viable adults with >95% loss of GATA-6 protein in the heart. These latter mice were subjected to pressure overload–induced hypertrophy for 2 and 6 weeks, which showed a significant reduction in cardiac hypertrophy similar to that observed
Gata4
heart-specific deleted mice.
Gata6
-deleted mice subjected to pressure overload also developed heart failure, whereas control mice maintained proper cardiac function.
Gata6
-deleted mice also developed less cardiac hypertrophy following 2 weeks of angiotensin II/phenylephrine infusion. Controlled GATA-6 overexpression in the heart induced hypertrophy with aging and predisposed to greater hypertrophy with pressure overload stimulation. Combinatorial deletion of
Gata4
and
Gata6
from the adult heart resulted in dilated cardiomyopathy and lethality by 16 weeks of age. Mechanistically, deletion of
Gata6
from the heart resulted in fundamental changes in the levels of key regulatory genes and myocyte differentiation–specific genes.

Conclusions:

These results indicate that GATA-6 is both necessary and sufficient for regulating the cardiac hypertrophic response and differentiated gene expression, both alone and in coordination with GATA-4.
Enhanced Fibroblast–Myocyte Interactions in Response to Cardiac Injury
Authors: Vasquez Carolina , Mohandas Poornima , Louie Karen L. , Benamer Najate , Bapat Ashwini C. , Morley Gregory E.
Published: August 2010

Rationale:

A critical event in the development of cardiac fibrosis is the transformation of fibroblasts into myofibroblasts. The electrophysiological consequences of this phenotypic switch remain largely unknown.

Objective:

Determine whether fibroblast activation following cardiac injury results in a distinct electrophysiological phenotype that enhances fibroblast–myocyte interactions.

Methods and Results:

Neonatal rat myocyte monolayers were treated with media (CM) conditioned by fibroblasts isolated from normal (Fb) and infarcted (MI-Fb) hearts. Fb and MI-Fb were also plated on top of myocyte monolayers at 3 densities. Cultures were optically mapped after CM treatment or fibroblast plating to obtain conduction velocity and action potential duration (APD
70
). Intercellular communication and connexin43 expression levels were assessed. Membrane properties of Fb and MI-Fb were evaluated using patch clamp techniques. MI-Fb CM treatment decreased conduction velocity (11.1%) compared to untreated myocyte cultures. APD
70
was reduced by MI-Fb CM treatment compared to homocellular myocyte culture (9.4%) and Fb CM treatment (6.4%). In heterocellular cultures, MI-Fb conduction velocities were different from Fb at all densities (+29.8%, −23.0%, and −16.7% at 200, 400, and 600 cells/mm
2
, respectively). APD
70
was reduced (9.6%) in MI-Fb compared to Fb cultures at 200 cells/mm
2
. MI-Fb had more hyperpolarized resting membrane potentials and increased outward current densities. Connexin43 was elevated (134%) in MI-Fb compared to Fb. Intercellular coupling evaluated with gap fluorescence recovery after photobleaching was higher between myocytes and MI-Fb compared to Fb.

Conclusions:

These data demonstrate cardiac injury results in significant electrophysiological changes that enhance fibroblast–myocyte interactions and could contribute to the greater incidence of arrhythmias observed in fibrotic hearts.
Early Recurrent Ischemic Stroke Complicating Intravenous Thrombolysis for Stroke
Authors: Awadh Mostafa , MacDougall Niall , Santosh Celestine , Teasdale Evelyn , Baird Tracey , Muir Keith W.
Published: August 2010

Background and Purpose—

Mechanisms of early neurologic deterioration after treatment with intravenous, recombinant, tissue-type plasminogen activator (IV rt-PA) include symptomatic intracerebral hemorrhage (SICH) and early recurrent ischemic stroke. We observed a number of cases of acute deterioration due to recurrent ischemic events.

Methods—

We undertook a single-center, retrospective analysis of consecutive acute stroke patients treated with IV rt-PA between January 2006 and December 2008 to define the incidence of early neurologic deterioration (≥4-point drop on the National Institutes of Health Stroke Scale within 72 hours) and its mechanism. Deterioration was attributed to SICH when associated with a PH1 or PH2 hemorrhage on postdeterioration computed tomography scans, to recurrent ischemic stroke when there was clinical and radiologic evidence of a new territorial infarction or new vessel occlusion, and otherwise to evolution of the incident stroke.

Results—

Of 228 consecutive IV rt-PA–treated patients, 34 (15%) developed early neurologic deterioration, 18 (8%) secondary to incident strokes 10 (4.4%) due to SICH, and 6 (2.6%) due to early recurrent ischemic events, which were significantly associated with atrial fibrillation (present in 5 of 6 patients; 4 paroxysmal, 1 permanent). In 4 patients, sudden clinical deterioration developed during or shortly after IV rt-PA infusion, and in 2, deterioration developed 3 days later. All died 2 days to 2 weeks later. The single case without atrial fibrillation had a recurrent, contralateral, middle cerebral artery stroke during IV rt-PA infusion and multiple high-signal emboli detected by transcranial Doppler. Early recurrent ischemic stroke accounted for 5 of 12 (42%) cases of early neurologic deterioration in patients with atrial fibrillation.

Conclusion—

In this single-center series, the incidence of early recurrent ischemic stroke after IV rt-PA was 2.6% and was associated with previous atrial fibrillation.
Four Conceptions of Freedom
Authors: Spector Horacio
Published: August 2010

Contemporary political philosophers discuss the idea of freedom in terms of two distinctions: Berlin’s famous distinction between negative and positive liberty, and Skinner and Pettit’s divide between liberal and republican liberty. In this essay I proceed to recast the debate by showing that there are two strands in liberalism, Hobbesian and Lockean, and that the latter inherited its conception of civil liberty from republican thought. I also argue that the contemporary debate on freedom lacks a perspicuous account of the various conceptions of freedom, mainly because it leaves aside the classic contrast between natural liberty and civil liberty. Once we consider both the negative/positive distinction and the natural/civil one, we can classify all conceptions of freedom within four basic irreducible categories. In light of the resulting framework I show that there are two distinct conceptions of republican liberty, natural and civil, and that the former is coupled with an ideal of individual self-control.
Comparing Measures of National Power
Authors: Hyung Min Kim
Published: August 2010

This article proposes a new national power concept, using the social network perspective, called ‘structural network power,’ which is defined as the power of an individual state arising from its location within the networks of international relations. This article primarily aims to compare and contrast the new measure of national power (structural network power index [SNPI]) to the previous measures of national power (focusing on the correlates of war composite index of national capabilities [CINC]), which is the most widely used measure of national power in international relations. A comparison of the two measures is performed using two sets of analyses: confirmatory factor analyses and correlation analyses (Pearson and Spearman). The results clearly show that the two power measures tap into two different aspects of national power — one measured by the attribute-based power concept and the other measured by the relations-based power concept — and that the measurement model of the new national power measure performs far better than that of previous national power measures. Based on these results, scholars are advised to consider different aspects and measures of national power when they study national power and its application to the phenomena in the fields of comparative politics and international relations.
Review Article: Extended producer responsibility for packaging wastes and WEEE - a comparison of implementation and the role of local authorities across Europe
Authors: Cahill Rachel , Grimes Sue M , Wilson David C
Published: August 2010

A comparison of the implementation of extended producer responsibility (EPR) to packaging waste and waste electrical and electronic equipment (WEEE) is presented for a representative sample of eleven European Union countries based on five indicators: stakeholders and responsibilities; compliance mechanisms; role of local authorities; financing mechanisms and merits and limitations, with four countries selected for more detailed case study analysis. Similarities, trends and differences in national systems are highlighted with particular focus on the role of local authorities and their relationship with obligated producers and the effect on the operation and success of each system. The national systems vary considerably in design, in terms of influence of pre-existing policy and systems, methods of achieving producer compliance (multiple or single collective schemes), fee structures, targets, waste stream prioritization and local authority involvement. Differing approaches are evident across all member states with respect to the role played by local authorities, responsibility apportioned to them, and the evolution of working relationships between obligated producers and municipalities. On the whole, EPR for packaging and WEEE has been successfully implemented throughout Europe in terms of Directive targets. It is, however, clear that the EPR systems currently in application across Europe differ primarily due to contrasting opinion on the legitimacy of local authorities as stakeholders and, in some cases, a fear on the part of industry of associated costs. Where local authorities have been engaged in the design and implementation of national systems, existing infrastructure used and defined roles established for producers and local authorities, results have been significantly more positive than in the cases where local authorities have had limited engagement.
Representing Taiwan: International sport, ethnicity and national identity in the Republic of China
Authors: Bairner Alan , Dong-Jhy Hwang
Published: August 2010

This article outlines and analyses the political character of Taiwan’s relationship with international sport, and in particular with the Olympic movement. In so doing, it seeks to add to the understanding of the links between sport and the formation and reproduction of national identities, with specific reference to the various cultural and ethnic identities of Taiwan, and to contribute to a more nuanced understanding of the relationship between ethnic and civic nationalism. The idea of the ‘New Taiwanese’ involves an ethnically divided people coming to see themselves as a cohesive group (Wong, 2001). Success in international sport can contribute to this process as it has in other post-colonial settings. Precisely how national identity formation in Taiwan will further develop, however, is difficult, if not impossible, to predict. What is certain, however, is that sport will continue to play a significant role in the unfolding process.