bluuebunny/crossref_metadata_2025 huggingface dataset:
Conservation Threat of Increasing Fire Frequencies in the Western Ghats, India
Authors: KODANDAPANI NARENDRAN , COCHRANE MARK A. , SUKUMAR R.
Published: December 2004

Abstract: 
The acceleration of processes such as forest fragmentation and forest fires in landscapes under intense human pressures makes it imperative to quantify and understand the effects of these processes on the conservation of biodiversity in these landscapes. We combined information from remote‐sensing imagery and ground maps of all fires in the Mudumalai Wildlife Sanctuary (MWLS) in the Western Ghats of India over 14 years (1989–2002). These spatial data on fire occurrence were integrated with maps of vegetation types found in the MWLS to examine fire conditions in each. We calculated the average fire‐return interval for each of the vegetation types individually and for the MWLS as a whole. Using vegetation data from the larger Nilgiri Biosphere Reserve and the entire Western Ghats region, we conservatively estimated fire‐frequency information for these larger regions. Because the MWLS does not contain tropical evergreen or montane forests, we were unable to estimate fire conditions in these forest types, which represent 31% of all Western Ghats vegetation cover. For the MWLS, all vegetation types had average fire‐return intervals of <7 years, and the sanctuary as a whole had a fire‐return interval of 3.3 years. Compared with a 13‐year MWLS fire data set from 1909–1921, this represents a threefold increase in fire frequency over the last 80 years. We estimated average fire‐return intervals of roughly 5 years for both the larger Nilgiri Biosphere Reserve and the entire Western Ghats region. Given other recent reports, the estimated fire frequencies for the Western Ghats forests outside protected reserves are conservative. We conclude that the current fire regime of the Western Ghats poses a severe and persistent conservation threat to forests both within and outside protected reserves.
Edge Effects and Isolation: Red‐Backed Voles Revisited
Authors: TALLMON DAVID A. , MILLS L. SCOTT
Published: December 2004

Abstract: 
We examined demographic responses of California red‐backed voles (Clethrionomys californicus) to forest fragmentation in southwestern Oregon at sites where this species has previously shown negative responses to fragmentation. Voles were captured in live traps and released. Voles were rarely caught in clearcuts surrounding 11 forest fragments, but relative vole density did not decrease from the forest‐fragment interiors to edges. The first result agrees with previous findings at these sites 6 years earlier, but the latter result does not. There was no evidence that vole response to edge changes with fragment age. Two years of intensive mark‐recapture efforts at two forest‐fragment sites and two unfragmented (control) sites did not show negative effects of fragmentation on vole survival, an important demographic rate. Vole capture probabilities varied greatly across space and time on these four sites, which may explain the differences in vole responses to edge seen between this and the previous study. These results suggest that reliable appraisal of edge effects may be difficult for many species on small fragments because the data necessary to apply population estimators require great efforts to obtain and the use of indices leads to a confounding of detection probabilities with demographic change.
Ecological Correlates of Extinction Proneness in Tropical Butterflies
Authors: KOH LIAN PIN , SODHI NAVJOT S. , BROOK BARRY W.
Published: December 2004

Abstract: Widespread and rapid losses of natural habitats and biodiversity have made the identification of extinction‐prone species a major challenge in conservation biology. We assessed the relative importance of biologically relevant species traits (e.g., body size, ecological specialization) obtained from published records to determine the extinction probability of butterflies in a highly disturbed tropical landscape (i.e., Singapore). We also developed a taxon‐specific model to estimate the extinction proneness of butterflies in Southeast Asia. Logistic regression analyses showed that adult habitat specialization, larval host plant specificity, geographical distribution, sexual dichromatism, and congenor density were significant and independent determinants of butterfly extinctions in Singapore. Among these traits, specificity of larval host plant and adult habitat specialization were the best correlates of extinction risks. We used this phenomenological extinction‐regression model to estimate the relative extinction proneness of 416 butterfly species in Southeast Asia. Our results illustrate the utility of available taxon‐specific data for a localized area in estimating the extinction proneness of closely related species on a regional scale. When intensive field studies are not forthcoming, especially in regions suffering from rapid biodiversity losses (e.g., Southeast Asia), similar approaches could be used to estimate extinction threats for other taxonomic groups.
Relative Contributions of Sampling Error in Initial Population Size and Vital Rates to Outcomes of Population Viability Analysis
Authors: McLOUGHLIN PHILIP D. , MESSIER FRANÇOIS
Published: December 2004

Abstract: 
We evaluated the relative contributions of sampling error (randomly chosen standard errors applied as 0–30% of parameter estimates) in initial population size and vital rates (survival and reproduction) to the outcome of a simulated population viability analysis for grizzly bears ( Ursus arctos). Error in initial population size accounted for the largest source of variation (model II analysis of variance, F
25,5= 10.8, p =0.00001) in simulation outcomes, explaining 60.5% of the variance. In contrast, error in vital rates contributed little to simulation outcomes (F
25,5= 0.61, p =0.70), accounting for only 2.4% of model variation. Reduced global variation in vital rates, as a result of independent random sampling of annual deviates for each parameter, likely contributed to the results. Errors in estimates of initial population size, if ignored in PVA, have the potential to leave managers with estimates of population persistence that are of little value for making management decisions.
A Concentric Analysis of the Impact of Urbanization on the Threatened European Tree Frog in an Agricultural Landscape
Authors: PELLET JÉRÔME , GUISAN ANTOINE , PERRIN NICOLAS
Published: December 2004

Abstract: 
Pond‐breeding amphibians are affected by site‐specific factors and regional and landscape‐scale patterns of land use. Recent anthropogenic landscape modifications (drainage, agriculture intensification, larger road networks, and increased traffic) affect species by reducing the suitable habitat area and fragmenting remaining populations. Using a robust concentric approach based on permutation tests, we evaluated the impact of recent landscape changes on the presence of the endangered European tree frog (Hyla arborea) in wetlands. We analyzed the frequency of 1 traffic and 14 land‐use indices at 20 circular ranges (from 100‐m up to 2‐km radii) around 76 ponds identified in western Switzerland. Urban areas and road surfaces had a strong adverse effect on tree frog presence even at relatively great distances (from 100 m up to 1 km). When traffic measurements were considered instead of road surfaces, the effect increased, suggesting a negative impact due to a vehicle‐induced effect. Altogether, our results indicate that urbanization and traffic must be taken into account when pond creation is an option in conservation management plans, as is the case for the European tree frog in western Switzerland. We conclude that our easy‐to‐use and robust concentric method of analysis can successfully assist managers in identifying potential sites for pond creation, where probability of the presence of tree frogs is maximized.
Similarity Analysis for Nonequilibrium Turbulent Boundary Layers*
Authors: Castillo Luciano , Wang Xia
Published: December 2004

In his now classical paper on pressure gradient turbulent boundary layers, Clauser concluded that equilibrium flows were very special flows difficult to achieve experimentally and that few flows were actually in equilibrium [1]. However, using similarity analysis of the Navier–Stokes equations, Castillo and George [2] defined an equilibrium flow as one where the pressure parameter, Λ=[δ/ρU∞2dδ/dx]dP∞/dx, was a constant. They further showed that most flows were in equilibrium and the exceptions were nonequilibrium flows where Λ≠constant. Using the equations of motion and similarity analysis, it will be shown that even nonequilibrium flows, as those over airfoils or with sudden changes on the external pressure gradient, are in equilibrium state, but only locally. Moreover, in the case of airfoils where the external pressure gradient changes from favorable to zero then to adverse, three distinctive regions are identified. Each region is given by a constant value of Λθ, and each region remains in equilibrium with Λθ=constant, respectively.
Shape Optimization of Forward-Curved-Blade Centrifugal Fan with Navier-Stokes Analysis
Authors: Kim Kwang-Yong , Seo Seoung-Jin
Published: December 2004

In this paper, the response surface method using a three-dimensional Navier-Stokes analysis to optimize the shape of a forward-curved-blade centrifugal fan is described. For the numerical analysis, Reynolds-averaged Navier-Stokes equations with the standard k-ε turbulence model are discretized with finite volume approximations. The SIMPLEC algorithm is used as a velocity–pressure correction procedure. In order to reduce the huge computing time due to a large number of blades in forward-curved-blade centrifugal fan, the flow inside of the fan is regarded as steady flow by introducing the impeller force models. Four design variables, i.e., location of cutoff, radius of cutoff, expansion angle of scroll, and width of impeller, were selected to optimize the shapes of scroll and blades. Data points for response evaluations were selected by D-optimal design, and a linear programming method was used for the optimization on the response surface. As a main result of the optimization, the efficiency was successfully improved. Effects of the relative size of the inactive zone at the exit of impeller and momentum fluxes of the flow in scroll on efficiency were further discussed. It was found that the optimization process provides a reliable design of this kind of fan with reasonable computing time.
On Cross-Flow Fan Theoretical Performance and Efficiency Curves: An Energy Loss Analysis on Experimental Data
Authors: Toffolo Andrea
Published: December 2004

Contrary to conventional turbomachinery, cross-flow fan flow field is non-axisymmetrical and its complex configuration strongly affects performance and efficiency characteristic curves. The formulation of a theory on cross-flow fan operation is made even tougher since the strength and the eccentricity of the vortex that forms within the impeller are deeply influenced by the geometry of the impeller and of the casing as well. In this paper, a numerical reconstruction of the flow field, validated against an extensive systematic database of global and local experimental measurements, is analyzed. The aim is to achieve a general interpretation of performance and efficiency curves, and to lead them back to one theoretical archetype, whatever the fan configuration being considered.
An Experimental Investigation of Thermal Effects in a Cavitating Inducer
Authors: Franc Jean-Pierre , Rebattet Claude , Coulon Alain
Published: December 2004

The thermal effects which affect the development of leading edge cavitation in an inducer were investigated experimentally using refrigerant R114. For different operating conditions, the evolution of the cavity length with the cavitation parameter was determined from visualizations. The tests were conducted up to two-phase breeding. The comparison of tests in R114 and in cold water allowed us to estimate the amplitude of the thermodynamic effect. The results show that the B-factor depends primarily upon the degree of development of cavitation but not significantly upon other parameters such as the inducer rotation speed or the fluid temperature, at least in the present domain of investigation. These trends are qualitatively in agreement with the classical entrainment theory. In addition, pressure fluctuations spectra were determined in order to detect the onset of cavitation instabilities and particularly of alternate blade cavitation and rotating cavitation. If the onset of alternate blade cavitation appeared to be connected to a critical cavity length, the results are not so clear concerning the onset of rotating cavitation.
The impact of tumor motion upon CT image integrity and target delineation
Authors: Gagné Isabelle M. , Robinson Don M.
Published: December 2004

Accurate planning target volume delineation is vital to the success of conformal radiation techniques such as standard three‐dimensional conformal radiotherapy and intensity modulated radiation therapy. With the exception of breath‐hold schemes, all current approaches acquire images while the tumor is nonstationary and, as such, are subject to the presence of motion artifacts. In lung cancer sites where tumor mobility can be significant, the detrimental effect of these motion‐induced distortions on image quality and subsequently target volume delineation cannot be ignored in the pursuit of improved treatment outcomes. To investigate the fundamental nature and functional dependence of computed tomography (CT) artifacts associated with lung tumor motion, and the implications for tumor delineation, a filtered backprojection algorithm was developed in MATLAB to generate transverse CT simulation images. In addition, a three‐dimensional phantom capable of mimicking the essential motions of lung tumors was constructed for experimental verification. Results show that the spatial extent of a mobile object is distorted from its true shape and location and does not accurately reflect the volume occupied during the extent of motion captured. The presence of motion also negatively impacts image intensity (density) integrity rendering accurate volume delineation highly problematic and calling into question the use of such data in CT‐based heterogeneity correction algorithms for dosimetric calculation.
Jiao Qi Disease in Medieval China
Authors: Fan Ka Wai
Published: December 2004

The disease, Jiao Qi, thought by modern scholars to be beriberi, was prevalent in medieval China. This article reviews the research literature, both ancient and modern, concerning the history of Jiao Qi, and evaluates the research methods used by modern scholars writing about Jiao Qi. The article emphasizes the importance of considering not only the symptoms of the disease but also its epidemiological features, including environmental aspects, and the therapeutic measures employed to treat it. The current author concludes that there are problems with the historical materials, such as inconsistency and bias, and that limitations are inherent in the approaches used to identify an ancient disease according to modern medical criteria.
CHIRAL QUARK MODEL (χQM) AND THE NUCLEON SPIN
Authors: DAHIYA HARLEEN , GUPTA MANMOHAN
Published: December 2004

Using χ QM with configuration mixing, the contribution of the gluon polarization to the flavor singlet component of the total spin has been calculated phenomenologically through the relation [Formula: see text] as defined in the Adler–Bardeen scheme, where ΔΣ on the right-hand side is Q2 independent. For evaluation the contribution of gluon polarization [Formula: see text], ΔΣ is found in the χ QM by fixing the latest E866 data pertaining to [Formula: see text] asymmetry and the spin polarization functions whereas ΔΣ(Q2) is taken to be 0.30±0.06 and αs=0.287±0.020, both at Q2=5 GeV 2. The contribution of gluon polarization Δg' comes out to be 0.33 which leads to an almost perfect fit for spin distribution functions in the χ QM . When its implications for magnetic moments are investigated, we find perfect fit for many of the magnetic moments. If an attempt is made to explain the angular momentum sum rule for proton by using the above value of Δg', one finds the contribution of gluon angular momentum to be as important as that of the [Formula: see text] pairs.
Obesity-Associated Hypertension
Authors: Rahmouni Kamal , Correia Marcelo L.G. , Haynes William G. , Mark Allyn L.
Published: December 2004

Obesity is strongly associated with hypertension and cardiovascular disease. Several central and peripheral abnormalities that can explain the development or maintenance of high arterial pressure in obesity have been identified. These include activation of the sympathetic nervous system and the renin-angiotensin–aldosterone system. Obesity is also associated with endothelial dysfunction and renal functional abnormalities that may play a role in the development of hypertension. The continuing discovery of mechanisms regulating appetite and metabolism is likely to lead to new therapies for obesity-induced hypertension. Better understanding of leptin signaling in the hypothalamus and the mechanisms of leptin resistance should facilitate therapeutic approaches to reverse the phenomenon of selective leptin resistance. Other hunger and satiety signals such as ghrelin and peptide YY are potentially attractive therapeutic strategies for treatment of obesity and its complications. These recent discoveries should lead to novel strategies for treatment of obesity and hypertension.
Women and Property Rights in Al-Andalus and the Maghrib: Social Patterns and Legal Discourse
Authors: Shatzmiller Maya
Published: December 2004

This essay focuses on the implementation of women's property rights in al-Andalus and the Maghrib in the period between the tenth and fifteenth centuries, as reflected in legal sources. An examination of Islamic property and family law, judicial practice, and the attitude of jurists toward women indicates that the majority of Muslim women owned property independently at some point in their lives, that women acquired property at every stage of the life-cycle, and that women played an important role in the intergenerational transmission of property and in keeping familial property intact. At the same time, the legal institutions of guardianship (wilāya) and interdiction (ḥajr) placed constrains on the ability of women to exercise effective control of their property during adulthood. The implementation of women's sharʿī property rights by qādīs and muftīs had important consequences for women's relationships with their families, especially their husbands. That male domination was never complete in propertied families calls into question the characterization of the Muslim family as “patriarchal” and points to the need for a new social, cultural, and economic explanation of the nature of the Muslim family.
Compelling Defendant's Appearance at Court in Islamic Law
Authors: Ziadeh Farhat
Published: December 2004

Different legal systems have employed a variety of measures to insure the appearance of the defendant in court. The earliest conception of an action in Rome and in pre-Islamic Arabia was the voluntary appearance of both parties before a recognized or prestigious authority. Thus, early Roman law could not pass judgment against a defendant who failed to appear, either voluntarily or involuntarily. The idea that the court could give a judgment in the plaintiff's absence—the so-called judgment by default—took a long time to materialize in the West. Classical Islamic law requires that the defendant or his legal representative (wakīl) be present for a judgment to be given. This requirement is predicated on the assumption that the primary function of the judge is conciliation of the parties and not necessarily the vindication of rights. The law describes various measures that may be employed to force the defendant to appear in court. Failing that, it provides for the appointment of a legal representative for the defendant. Judgment by default was introduced into Muslim countries only in modern times under the influence of Western codes of procedure.
Orthodox Christians in the Kadı Courts: The Practice of the Sofia Sheriat Court, Seventeenth Century
Authors: Gradeva Rossitsa
Published: December 2004

The attitude of Balkan Christians to Ottoman rule has been subject to various, often contradictory, assessments. In this essay I examine one aspect of this subject, namely, the Christian attitude toward the sheriat court as a judicial institution, as reflected in kadı sicils from Sofia and other Balkan cities and in documents issued by Orthodox Christian ecclesiastical authorities from the sixteenth to the eighteenth centuries. Examination of these sources reveals that Christians frequently chose the sheriat judge over that of the church courts. In most cases this behaviour can be explained by the desire of the Christian litigants to seek out the court that would provide the most favourable solution to the dispute. The participation of Christians in sheriat court proceedings strengthens the impression that they did not avoid the sheriat court in practice, despite the hostility manifested by Christian religious authorities toward such behaviour. Indeed, the sources point to relatively smooth relations between the two communities in the Ottoman Balkan provinces in the period immediately preceding the national awakening of Balkan peoples.
Imperial Authority, Benefactions and Endowments (Awqāf) in Mughal India
Authors: Kozlowski Gregory
Published: December 2004

Islamic theology grants temporal rulers no divine right to command. Muslim kings have often tried to win a kind of legitimacy by offering various kinds of patronage to religious notables. In the Mamluk, Ottoman and Safavi states, endowments (Awqāf) were the most common form of benefaction. The Timurids of India, however, favored other forms of grants. They did so, in part, to adjust to religious centers and networks of learned/holy men established by the Muslim rulers who had preceded them.
La Fabrication des Lames Damassées en Orient
Authors: Rāġib Yūsuf
Published: December 2004

Although steel ornamented with designs has stirred interest in Europe for several centuries, the numerous formulas (for its manufacture) transmitted by medieval sources in Arabic and Persian have not yet been the object of an investigative study. Moreover, the many formulas for the tempering (of this material) have never been seriously examined. However, they reveal some of the secrets of the damasked plates which metallurgists have attempted to discover since the last century. These secrets have only been analysed through the study of recent specimens which are a long way off from the quality of ornamented steel of the High Middle Ages (such as that made by Yemenites, Indians, and Malaysians), whose splendour, resistance, and litheness are described by oriental sources.
Horizontally Oriented Plates in Clouds
Authors: Bréon François-Marie , Dubrulle Bérengère
Published: December 2004

Horizontally oriented plates in clouds generate a sharp specular reflectance signal in the glint direction, often referred to as “subsun.” This signal (amplitude and width) may be used to analyze the relative area fraction of oriented plates in the cloud-top layer and their characteristic tilt angle to the horizontal. Use is made of spaceborne measurements from the Polarization and Directionality of the Earth Reflectances (POLDER) instrument to provide a statistical analysis of these parameters. More than half of the clouds show a detectable maximum reflectance in the glint direction, although this maximum may be rather faint. The typical effective fraction (area weighted) of oriented plates in clouds lies between 10−3 and 10−2. For those oriented plates, the characteristic tilt angle is less than 1° in most cases. These low fractions imply that the impact of oriented plates on the cloud albedo is insignificant. The largest proportion of clouds with horizontally oriented plates is found in the range 500– 700 hPa, in agreement with typical in situ observation of plates in clouds.

A simple aerodynamic model is proposed that accounts for the orienting torque of the flow as the plate falls under its own gravity and the disorienting effects of Brownian motion and atmospheric turbulence. The model indicates that the horizontal plate diameters are in the range 0.1 to a few millimeters. For such sizes, Brownian forces have a negligible impact on the plate orientation. On the other hand, typical levels of atmospheric turbulence lead to tilt angles that are similar to those estimated from the glint observation.
Wind Profile and Drag Coefficient over Mature Ocean Surface Wave Spectra
Authors: Hara Tetsu , Belcher Stephen E.
Published: December 2004

The mean wind profile and the Charnock coefficient, or drag coefficient, over mature seas are investigated. A model of the wave boundary layer, which consists of the lowest part of the atmospheric boundary layer that is influenced by surface waves, is developed based on the conservation of momentum and energy. Energy conservation is cast as a bulk constraint, integrated across the depth of the wave boundary layer, and the turbulence closure is achieved by parameterizing the dissipation rate of turbulent kinetic energy. Momentum conservation is accounted for by using the analytical model of the equilibrium surface wave spectra developed by Hara and Belcher. This approach allows analytical expressions of the Charnock coefficient to be obtained and the results to be examined in terms of key nondimensional parameters. In particular, simple expressions are obtained in the asymptotic limit at which effects of viscosity and surface tension are small and the majority of the stress is supported by wave drag. This analytical model allows us to identify the conditions necessary for the Charnock coefficient to be a true constant, an assumption routinely made in existing bulk parameterizations.
AIDS Epidemic and Economic Growth: Testing for Causality
Authors: Ukpolo Victor
Published: December 2004

This article investigates the relationship between AIDS and economic growth for 17 African countries for the period 1990 to 1996. Previous studies have found mixed results, which may have been due to the adoption of inappropriate models (simulation and cross-country models). The pitfalls of such models can lead to spurious results. Our results, which are based on pooled time series, show a significantly negative relationship between AIDS and growth. This article’s unique contribution, however, is the use of the Granger-causality test procedure to examine the link between AIDS and growth in Africa. No previous study can be found that has conducted such examination. The results support the existence of bi-directional causal relationship between AIDS and growth in Africa for the period studied.
Lessons from Yorùbá Mythology
Authors: Adeleke Duro A.
Published: December 2004

Conflict management and resolution strategies often do not pay enough attention to traditional methods emanating from local cultural traditions. Many conflicts in sub-Saharan Africa are not responsive to contemporary approaches born in the West and implemented in conflict zones across the continent. In this article I specifically focus on the myths of the Yorùbá ethnic group in Nigeria as a way to demonstrate how myths from a given society can be helpful in crafting local solutions to local conflicts. After providing a brief overview of the relationship between myth and conflict, I will summarize and analyze five Yorùbá myths that provide cultural context to the Yorùbá experience, and then conclude with some lessons that can be applied to the conflict resolution process in general.
Corridors of Flight, Zones of Renewal
Authors: Heathcott Joseph , Murphy MáIre Agnes
Published: December 2004

This article examine show St. Louis public officials, business leaders, and urban planners responded to large-scale industrial disinvestment after World War II. The authors consider three major clusters of policy and planning activity: urban renewal, high-tech R&D, and tourism and entertainment. In each of these, they illuminate the values, assumptions, and institutional networks of political and business leaders as they shaped postwar industrial development. The authors demonstrate that local public officials and business leaders in St. Louis articulated a new vision for development based on an emerging metropolitan definition of problems and solutions. In effect, planners responded to inner-city industrial decline by restructuring spatial-economic relations across the metropolitan area. This metropolitan articulation of development and space guided restructuring and yielded a range of tangible yet uneven outcomes on the postwar landscape.
Acute Bacterial Meningitis in Children
Authors: Haase Mark R.
Published: December 2004

Despite advances in recent decades in management, including new and effective antimicrobials, children with bacterial meningitis still incur significant morbidity and mortality. Pathophysiologic processes including colonization and migration of the bacteria to blood, seeding of the meninges, and meningeal and brain inflammation have been largely elucidated, but more specific knowledge could lead to new effective therapies. Outside of the neonatal period, the most common causative organisms have been Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis. However, conjugate vaccines, especially the H influenzae type b preparation, have contributed significantly to steep declines in the incidence of meningitis. Optimal management consists of rapid diagnosis and administration of bactericidal antibiotics with properties allowing adequate penetration of the inflamed blood-brain barrier. Recently, development of microbial resistance has resulted in changes to recommended empiric antibiotic regimens. Novel therapies are under investigation; however, until controlled trials can be conducted, these therapies cannot be recommended.
How Local Governments Structure Contracts with Private Firms
Authors: Walls Margaret
Published: December 2004

Local governments often contract out many public services, including solid waste management. Although waste collection contracting is relatively straightforward, recycling is more complicated. Local governments have to figure out how to achieve multiple objectives: low-cost provision of service and a minimum level of service quality, along with attainment of recycling and waste-reduction goals. Who should own key assets, how fully to specify ex ante the service to be provided—including exactly what materials to collect what prices to charge households, and how to compensate contractors are but three of the difficult questions they must address. In this study, the author summarizes the economics literature on incomplete contracts to shed light on current waste management practices. She then shows results from an International City/County Management Association survey of over 1,000 U.S. communities and a detailed analysis of the structure of contracts in seven communities that have achieved high recycling rates.
Fiscal Reserves and State Own-Source Expenditure in Downturn Years
Authors: Hou Yilin
Published: December 2004

This article tests the effects of fiscal reserves on state total own-source expenditure in downturn years. Using a panel data set (fifty states, 1979 to 1999), the article uses the variance-from-trend as the dependent variable to estimate the effects of aggregate reserves as well as budget stabilization funds (BSF) and general fund surpluses (GFS) and obtain their respective coefficients. Two data sources on fiscal reserves are used: the Fiscal Survey of the States and the Comprehensive Annual Financial Report. The article provides evidence that fiscal reserves exert positive effects on state own-source expenditure in downturn years. The effects, however, are mainly from the BSF; the GFS coefficients, even when statistically significant, are only a quarter the size of those for the BSF. Nevertheless, states that do not have a BSF seem still to rely on the GFS. It appears that the BSF has taken over the counter cyclical stabilizing function from the GFS.
Oil and the Macroeconomy Since the 1970s
Authors: Barsky Robert B , Kilian Lutz
Published: December 2004

Increases in oil prices have been held responsible for recessions, periods of excessive inflation, reduced productivity and lower economic growth. In this paper, we review the arguments supporting such views. First, we highlight some of the conceptual difficulties in assigning a central role to oil price shocks in explaining macroeconomic fluctuations, and we trace how the arguments of proponents of the oil view have evolved in response to these difficulties. Second, we challenge the notion that at least the major oil price movements can be viewed as exogenous with respect to the US macroeconomy. We examine critically the evidence that has led many economists to ascribe a central role to exogenous political events in modeling the oil market, and we provide arguments in favor of ‘reverse causality’ from macroeconomic variables to oil prices. Third, although none of the more recent oil price shocks has been associated with stagflation in the US economy, a major reason for the continued popularity of the oil shock hypothesis has been the perception that only oil price shocks are able to explain the US stagflation of the 1970s. We show that this is not the case.
The Purchasing Power Parity Debate
Authors: Taylor Alan M , Taylor Mark P
Published: December 2004

Originally propounded by the sixteenth-century scholars of the University of Salamanca, the concept of purchasing power parity (PPP) was revived in the interwar period in the context of the debate concerning the appropriate level at which to re-establish international exchange rate parities. Broadly accepted as a long-run equilibrium condition in the post-war period, it was first advocated as a short-run equilibrium by many international economists in the first few years following the breakdown of the Bretton Woods system in the early 1970s and then increasingly came under attack on both theoretical and empirical grounds from the late 1970s to the mid 1990s. Accordingly, over the last three decades, a large literature has built up that examines how much the data deviated from theory, and the fruits of this research have provided a deeper understanding of how well PPP applies in both the short run and the long run. Since the mid 1990s, larger datasets and nonlinear econometric methods, in particular, have improved estimation. As deviations narrowed between real exchange rates and PPP, so did the gap narrow between theory and data, and some degree of confidence in long-run PPP began to emerge again. In this respect, the idea of long-run PPP now enjoys perhaps its strongest support in more than thirty years, a distinct reversion in economic thought.

Our willingness to pay a certain price for foreign money must ultimately and essentially be due to the fact that this money possesses a purchasing power as against commodities and services in that country. On the other hand, when we offer so and so much of our own money, we are actually offering a purchasing power as against commodities and services in our own country. Our valuation of a foreign currency in terms of our own, therefore, mainly depends on the relative purchasing power of the two currencies in their respective countries.
Simultaneous chiral analyses of multiple analytes: case studies, implications and method development considerations
Authors: Srinivas Nuggehally R.
Published: December 2004

The ﬁeld of chiral separations had a modest beginning some two decades ago. However, due to rapid technological advancement coupled with simultaneous availability of innovative chiral stationary phases and novel chiral derivatization agents, the ﬁeld of chiral separations has now totally outpaced many other separation ﬁelds. Keeping pace with rapid changes in the ﬁeld of chiral separations, investigators continue to add stereoselective pharmacokinetic, pharmacodynamic, pharmacologic and toxicological data of new and/or marketed racemic compounds to the literature. Examination of the evolution of chiral separations suggests that in the beginning many investigators attempted to separate and quantify a single pair of enantiomers, adopting either direct (separation made on a chiral stationary phase) or indirect (separation made following precolumn conversion of enantiomers to corresponding diastereomers) approaches. However, more recent trends in chiral separations suggest that investigators are attempting to separate and quantify multiple pairs of enantiomers with available technologies. Added to this, some interesting trends have been observed in many of the recently reported chiral applications, including preferences regarding internal standard selection, mobile phase contents and composition, sorting out issues with mass spectrometric detection, determination of elution order, analytical manipulations of metabolite(s) without reference standards and addressing some speciﬁcity‐related issues. This review mainly focuses on chiral separations involving multiple chiral analytes and attempts to justify the need for such chiral separations involving multiple analytes. In this context, several cases studies are described on the utility and applicability of such chiral separations under discrete headings to provide an account to the readership on the implications of such tasks. The topics of case studies covered in this review include: (a) therapy markers—differentiation from drug abuse and/or applicability in forensics; (b) role in pharmacogenetic/polymorphic evaluation; (c) monitoring and understaning the role of parent and active metabolite(s) in clinical and preclinical investigations; (d) exploration on the pharmacokinetic utility of an active chiral metabolite vis‐à‐vis the racemic parent moiety; (e) understanding the chirality play in delineating peculiar toxic effects; (f) exploration of chiral inversion phenomenon, and understanding the role of stereoselective metabolism. For the further beneﬁt of readership, some select examples (n = 19) of the separation of multiple chiral analytes with appropriate information on chromatography, detection system, validation parameters and applicable conclusion are also provided. Finally, the review covers some useful considerations for method development involving multiple chiral analytes. Copyright © 2004 John Wiley & Sons, Ltd.
Therapeutic monitoring of imipramine and desipramine by micellar liquid chromatography with direct injection and electrochemical detection
Authors: Bose Devasish , Martinavarro‐Domínguez Adrià , Gil‐Agustí Mayte , Carda‐Broch Samuel , Durgbanshi Abhilasha , Capella‐Peiró Maria‐Elisa , Esteve‐Romero Josep
Published: December 2004

A micellar liquid chromatographic (MLC) procedure was developed for the clinical monitoring of imipramine and its active metabolite, desipramine. The determination of these highly hydrophobic substances was carried out after direct injection of the serum samples using a mobile phase composed of 0.15 m SDS–6% (v/v) pentanol buffered at pH 7, pumped at 1.5 mL/min into a C18 column (250 × 4.6 mm), and electrochemical detection at 650 mV. Using this MLC method, calibration was linear (r > 0.995) and the limits of detection (ng/mL) were 0.34 and 0.24 for imipramine and desipramine, respectively. Repeatabilities and intermediate precision were tested at three different concentrations in the calibration range and a CV (%) below 2.2 was obtained. In this MLC procedure, the serum is determined without treatment, thus allowing repeated serial injections without changes in retention factors, and reducing the time and consumables required to carry out the pretreatment process. The assay method can be applied to the routine determination of serum imipramine and its metabolite in therapeutic drug monitoring. Copyright © 2004 John Wiley & Sons, Ltd.
A validated HPLC method with electrochemical detection for simultaneous assay of 5‐aminosalicylic acid and its metabolite in human plasma
Authors: Palumbo Giancarlo , Bacchi Simona , Primavera Luisa , Palumbo Paola , Carlucci Giuseppe
Published: December 2004

A high‐performance liquid chromatographic method was developed, validated and applied to the simultaneous determination of 5‐aminosalicylic acid (5‐ASA) and its acetylated metabolite (acetyl‐5‐ASA) in human plasma. The method involves liquid–liquid extraction with methanol followed by isocratic reversed‐phase chromatography on a Kromasil KR100 C18 column with electrochemical detection. The recovery, selectivity, linearity, precision and accuracy of the method were evaluated from spiked human plasma samples. The effects of mobile phase composition, buffer concentration, mobile phase pH and concentration of organic modiﬁers on retention of 5‐ASA, acetyl 5‐ASA and internal standard were investigated. Limits' of detection were 5 ng/mL for 5‐ASA and 10 ng/mL for acetyl‐5‐ASA, respectively. The method can be used for supporting therapeutical drug monitoring and pharmacokinetic studies. Copyright © 2004 John Wiley & Sons, Ltd.
Regulation of 11β‐hydroxysteroid dehydrogenase type 1 and glucose‐stimulated insulin secretion in pancreatic islets of Langerhans
Authors: Ortsäter Henrik , Alberts Peteris , Warpman Ulrika , Engblom Lars O. M. , Abrahmsén Lars , Bergsten Peter
Published: December 2004

Background

In rodents, the enzyme 11β‐hydroxysteroid dehydrogenase type 1 (11β‐HSD1) converts inactive 11‐dehydrocorticosterone (DHC) into active corticosterone. The mRNA and activity of 11β‐HSD1 have been shown to be present in batch‐incubated pancreatic islets from the ob/ob mouse. In other tissues, 11β‐HSD1 expression has been demonstrated to be regulated by glucocorticoids. In the present study, the influence of DHC on 11β‐HSD1 levels and glucose‐induced changes in insulin secretion were studied in pancreatic islets isolated from the ob/ob mouse.

Methods

Western blotting with antiserum for 11β‐HSD1 verified the presence of 11β‐HSD1 in islets from obese ob/ob and normal C57BL/6J mice. Insulin secretion was determined by perifusing islets and assaying the perifusate with ELISA.

Results

Islets from the ob/ob mouse contained almost twofold more 11β‐HSD1 protein than islets from the C57BL/6J mouse. When islets from ob/ob mice were cultured with 50 nM DHC, the 11β‐HSD1 levels doubled compared with islets cultured in the absence of DHC. Selective inhibition of 11β‐HSD1 attenuated DHC‐induced increase in 11β‐HSD1 levels, as did an antagonist of the glucocorticoid receptor. In individually perifused ob/ob mouse islets, early and late phases of glucose‐stimulated insulin secretion (GSIS) were dose‐dependently inhibited by 5, 50 and 500 nM DHC. Whereas inclusion of 11β‐HSD1 inhibitors restored, addition of the glucocorticoid receptor antagonist attenuated the DHC‐mediated inhibition of GSIS.

Conclusions

Levels of 11β‐HSD1 in islets from ob/ob mice are positively regulated by DHC and could be lowered by a selective 11β‐HSD1 inhibitor and a glucocorticoid receptor antagonist. Increased levels of 11β‐HSD1 were associated with impaired GSIS. Copyright © 2004 John Wiley & Sons, Ltd.
Inferring species phylogenies from multiple genes: Concatenated sequence tree versus consensus gene tree
Authors: Gadagkar Sudhindra R. , Rosenberg Michael S. , Kumar Sudhir
Published: December 2004

Phylogenetic trees from multiple genes can be obtained in two fundamentally different ways. In one, gene sequences are concatenated into a super‐gene alignment, which is then analyzed to generate the species tree. In the other, phylogenies are inferred separately from each gene, and a consensus of these gene phylogenies is used to represent the species tree. Here, we have compared these two approaches by means of computer simulation, using 448 parameter sets, including evolutionary rate, sequence length, base composition, and transition/transversion rate bias. In these simulations, we emphasized a worst‐case scenario analysis in which 100 replicate datasets for each evolutionary parameter set (gene) were generated, and the replicate dataset that produced a tree topology showing the largest number of phylogenetic errors was selected to represent that parameter set. Both randomly selected and worst‐case replicates were utilized to compare the consensus and concatenation approaches primarily using the neighbor‐joining (NJ) method. We find that the concatenation approach yields more accurate trees, even when the sequences concatenated have evolved with very different substitution patterns and no attempts are made to accommodate these differences while inferring phylogenies. These results appear to hold true for parsimony and likelihood methods as well. The concatenation approach shows >95% accuracy with only 10 genes. However, this gain in accuracy is sometimes accompanied by reinforcement of certain systematic biases, resulting in spuriously high bootstrap support for incorrect partitions, whether we employ site, gene, or a combined bootstrap resampling approach. Therefore, it will be prudent to report the number of individual genes supporting an inferred clade in the concatenated sequence tree, in addition to the bootstrap support. J. Exp. Zool.(Mol. Dev. Evol.) 304B:000–000, 2005. © 2005 Wiley‐Liss, Inc.
Delayed extraction experiments using a repulsing potential before ion extraction: evidence of non‐covalent clusters as ion precursor in UV matrix‐assisted laser desorption/ionization. Part II—Dynamic effects with α‐cyano‐4‐hydroxycinnamic acid matrix
Authors: Fournier I. , Brunot A. , Tabet J. C. , Bolbach G.
Published: December 2004

Delayed extraction experiments were undertaken to gain a better insight into the dynamic effects involved in the ion formation in UV matrix‐assisted laser desorption/ionization. Part I1 was devoted to a 2,5‐dihydroxybenzoic (2,5‐DHB) matrix. The results clearly demonstrated the existence and the role of high‐mass precursors corresponding to a non‐covalent matrix–analyte association in ion formation. In this complementary study, ion flight time and abundance were studied as a function of the delay extraction time using the matrix α‐cyano‐4‐hydroxycinnamic acid (HCCA). Under our instrumental conditions, where ejected ions experienced a low repulsing electric field before extraction, two main results were obtained: (i) two ion components are observed in the peak profiles depending on the repulsing field, a first, major component (I) similar to that observed for 2,5‐DHB and a second, minor component (II) apparently triggered by the delayed extraction pulse, and (ii) ion time‐of‐flight variation vs delay time remained lower than that noted with 2,5‐DHB matrix, indicating that the initial axial velocity is smaller. The initial kinetic energy of matrix and low molecular mass peptide ions for the component I is not high enough to overcome the repulsing potential in the delay time range (200–2200 ns) and we have to assume that ions have non‐covalent clusters as precursors. Complete desolvation of these clusters–aggregates would be achieved through the extraction step. Simulations of the ion time‐of‐flight as a function of the delay time allow the determination of the average size of the precursors, typically 4500, 40000 and 50000 u for HCCA, ACTH 7–38 and bovine insulin quasi‐molecular ion, respectively, assuming that the precursors are singly charged. The size of these ion precursors is greater than that of those generated for 2,5‐DHB. For component II, ions are probably not solvated and they are directly desorbed from the target. Taking into account the results on HCCA and 2,5‐DHB matrices and other results from the literature, a general model for ion formation based on clusters as ion precursors is proposed and discussed. Copyright © 2004 John Wiley & Sons, Ltd.