bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dopamine receptor supersensitivity in rat subthalamus after 6‐hydroxydopamine lesions
Authors: Shen Ke‐Zhong , Zhu Zi‐Tao , Munhall Adam , Johnson Steven W. 
Published: December 2004

AbstractThe subthalamic nucleus (STN) receives direct dopaminergic innervation from the substantia nigra pars compacta, but the importance of this input in the pathophysiology of parkinsonism remains to be determined. We used whole‐cell patch‐clamp recordings in brain slices to study presynaptic dopaminergic modulation of synaptic inputs to the STN in unilateral 6‐hydroxydopamine (6‐OHDA)‐lesioned rats. Here, we report that dopamine was more potent for inhibiting GABA IPSCs and glutamate EPSCs in the STN ipsilateral to the lesion, and was less potent for suppressing IPSCs and EPSCs in the STN contralateral to the lesion, compared with the effects of dopamine in control STN. Dopamine reduced IPSCs with an IC50 value of 20.9 ± 3.6 µm in control STN, whereas IC50 values were 0.83 ± 0.15 and 55.1 ± 11.1 µm in STN ipsilateral and contralateral to 6‐OHDA lesions, respectively. Dopamine also inhibited EPSCs with an IC50 value of 12.8 ± 2.8 µm in control STN, whereas IC50 values were 4.5 ± 0.9 and 41.6 ± 9.8 µm in STN ipsilateral and contralateral to 6‐OHDA lesions, respectively. Results with paired stimuli to evoke EPSCs and IPSCs suggest that endogenous dopamine acts presynaptically to inhibit transmitter release in the STN. These results show that chronic dopamine denervation significantly alters the regulation of synaptic input to the STN. Our results also suggest that the STN may be an important target for levodopa therapy in Parkinson's disease.
Density‐dependent mortality in Pacific salmon: the ghost of impacts past?
Authors: Achord Stephen , Levin Phillip S. , Zabel Richard W. 
Published: December 2004

AbstractConservation biologists often ignore density dependence because at‐risk populations are typically small relative to historical levels. However, if populations are reduced as a result of impacts that lower carrying capacity, then density‐dependent mortality may exist at low population abundances. Here, we explore this issue in threatened populations of juvenile chinook salmon (Oncorhynchus tshawytscha). We followed the fate of more than 50 000 juvenile chinook in the Snake River Basin, USA to test the hypothesis that their survival was inversely associated with juvenile density. We also tested the hypotheses that non‐indigenous brook trout and habitat quality affect the presence or strength of density dependence. Our results indicate that juvenile chinook suffer density‐dependent mortality and the strength of density dependence was greater in streams in which brook trout were absent. We were unable to detect an effect of habitat quality on the strength of density dependence. Historical impacts of humans have greatly reduced population sizes of salmon, and the density dependence we report may stem from a shortage of nutrients normally derived from decomposing salmon carcasses. Cohorts of juvenile salmon may experience density‐dependent mortality at population sizes far below historical levels and recovery of imperiled populations may be much slower than currently expected.
ENSO, rainfall and temperature influences on extreme population declines among African savanna ungulates
Authors: Ogutu Joseph O. , Owen‐Smith Norman 
Published: December 2004

AbstractClimatic variation associated with the North Atlantic Oscillation (NAO) and El Niño‐Southern Oscillation (ENSO) has a widespread influence on the population dynamics of many organisms worldwide. While previous analyses have related the dynamics of northern ungulates to the NAO, there has been no comparable assessment for the species rich assemblages of tropical and subtropical Africa. Census records for 11 ungulate species in South Africa's Kruger National Park over 1977–96 reveal severe population declines by seven species, which were inadequately explained by indices of ENSO or its effects on annual rainfall totals. An additional influence was an extreme reduction in dry season rainfall, concurrent with and perhaps related to a regional temperature rise, possibly a signal of global warming. Boundary fencing now restricts range shifts by such large mammals in response to climatic variation. Our models project near extirpation of three ungulate species from the park's fauna should these climatic conditions recur.
Behaviourally structured populations persist longer under harsh environmental conditions
Authors: Petrovskii Sergei V. , Blackshaw Rod P. 
Published: December 2004

AbstractThe factors and mechanisms that enhance population persistence in a fragmented habitat and/or under harsh environmental conditions are of significant current interest. We consider the dynamics of a population in an isolated habitat surrounded by an unfavourable environment subject to different behavioural responses between the individuals. We assume that there are two responses available: one of them is aggression in its extreme form, the other is its contrary when an individual takes flight in order to avoid any contact with its conspecific. We show that a behaviourally structured population consisting of individuals with fixed behavioural responses is intrinsically less prone to extinction under harsh environmental condition than a population where the individuals can ‘choose’ between the two given behaviours. We also show that, contrary to an intuitively expected negative impact of aggression on population persistence, the optimal conditions for population persistence are reached when a considerable proportion of the individuals exhibit aggressive behaviour.
Stable isotope probing of rRNA and DNA reveals a dynamic methylotroph community and trophic interactions with fungi and protozoa in oxic rice field soil
Authors: Lueders Tillmann , Wagner Bianca , Claus Peter , Friedrich Michael W. 
Published: December 2004

SummaryStable isotope probing (SIP) is a novel technique to characterize structure and in situ function of active microbial populations, which is based on the incorporation of 13C‐labelled substrates into nucleic acids. Here, we have traced methylotrophic members of a rice field soil microbial community, which became active upon continuous addition of 13C‐methanol (<22 mM) as studied in microcosms. By combining rRNA‐ and DNA‐based SIP, as well as domain‐specific real‐time PCR detection of templates in fractions of centrifugation gradients, we were able to detect 13C‐labelled bacterial rRNA after 6 days of incubation. Fingerprinting and comparative sequence analysis of ‘heavy’ bacterial rRNA showed that mostly members of the Methylobacteriaceae and a novel clade within the Methylophilaceae formed part of the indigenous methylotrophic community. Over time, however, the Methylophilaceae were enriched. Unexpectedly, nucleic acids of eukaryotic origin were detected, mostly in intermediately 13C‐labelled gradient fractions. These eukaryotes were identified as fungi mostly related to Fusarium and Aspergillus spp., and also Cercozoa, known as predatory soil flagellates. The detection of fungi and protozoa in 13C‐enriched nucleic acid fractions suggests a possible involvement in either direct assimilation of label by the fungi, or a food web, i.e. that primary 13C‐methanol consuming methylotrophs were decomposed by fungi and grazed by protozoa.
Competitive interactions between Microdochium nivale var. majus, M. nivale var. nivale and Fusarium culmorum in planta and in vitro
Authors: Simpson Duncan R. , Thomsett Martha A. , Nicholson Paul 
Published: December 2004

Summary Microdochium nivale var. majus and var. nivale are economically important fungal pathogens of cereal seedlings, stem bases and ears, as is the toxigenic species Fusarium culmorum. Competition experiments on seedlings support an earlier report of differential host preference between the varieties of M. nivale on wheat and rye seedlings at 15°C, but showed that it does not extend across a broad range of temperatures. The studies showed that, although interaction is disadvantageous to the less virulent pathogen, it does not confer an advantage to the more virulent pathogen. In mixed inoculum experiments on wheat seedlings at 15°C and 20°C, F. culmorum suppressed the growth of both varieties of M. nivale. However, if M. nivale var. majus became established on the seedlings, it was able to co‐suppress colonization of wheat seedlings by F. culmorum. In contrast M. nivale var. nivale did not suppress F. culmorum significantly. The growth of M. nivale var. majus and F. culmorum was also co‐suppressed in liquid culture. Significantly, the accumulation of deoxynivalenol mycotoxin was also reduced in the mixed in vitro culture compared with axenic culture of F. culmorum. However, in vitro interaction studies on solidified media were of only limited use in predicting the outcome of competitions in planta.
Analysis of methanotrophic bacteria in Movile Cave by stable isotope probing
Authors: Hutchens Elena , Radajewski Stefan , Dumont Marc G. , McDonald Ian R. , Murrell J. Colin 
Published: December 2004

SummaryMovile Cave is an unusual groundwater ecosystem that is supported by in situ chemoautotrophic production. The cave atmosphere contains 1–2% methane (CH4), although much higher concentrations are found in gas bubbles that keep microbial mats afloat on the water surface. As previous analyses of stable carbon isotope ratios have suggested that methane oxidation occurs in this environment, we hypothesized that aerobic methane‐oxidizing bacteria (methanotrophs) are active in Movile Cave. To identify the active methanotrophs in the water and mat material from Movile Cave, a microcosm was incubated with a 10%13CH4 headspace in a DNA‐based stable isotope probing (DNA‐SIP) experiment. Using improved centrifugation conditions, a 13C‐labelled DNA fraction was collected and used as a template for polymerase chain reaction amplification. Analysis of genes encoding the small‐subunit rRNA and key enzymes in the methane oxidation pathway of methanotrophs identified that strains of Methylomonas, Methylococcus and Methylocystis/Methylosinus had assimilated the 13CH4, and that these methanotrophs contain genes encoding both known types of methane monooxygenase (MMO). Sequences of non‐methanotrophic bacteria and an alga provided evidence for turnover of CH4 due to possible cross‐feeding on 13C‐labelled metabolites or biomass. Our results suggest that aerobic methanotrophs actively convert CH4 into complex organic compounds in Movile Cave and thus help to sustain a diverse community of microorganisms in this closed ecosystem.
Behavioral Disorders in Pediatric Epilepsy: Unmet Psychiatric Need
Authors: Ott Derek , Siddarth Prabha , Gurbani Suresh , Koh Susan , Tournay Anne , Shields W. Donald , Caplan Rochelle 
Published: December 2004

Summary:  Purpose: This study examined the relation between psychiatric diagnosis and mental health services in children with epilepsy and the associated demographic, cognitive, linguistic, behavioral, and seizure‐related variables.Methods: The Kiddie Schedule for Affective Disorders and Schizophrenia (K‐SADS), the Child Behavior Checklist, the Test of Language Development, and the Wechsler Intelligence Scale for Children–Revised (WISC‐R) were administered to 114 children, aged 5 to 16 years, with either complex partial seizures (CPS) or primary generalized with absence (PGE, petit mal). A Diagnostic and Statistical Manual of Mental Disorders (DSM‐IV) diagnosis and information regarding mental health services were derived from the K‐SADS.Results: Although ∼60% of the subjects had a DSM‐IV psychiatric diagnosis, >60% received no mental health treatment. Absence of mental health care was associated with younger age, less parental education, limited number of antiepileptic drugs (AEDs; i.e., one or none), and higher verbal IQ. In addition, children with PGE and a single psychiatric diagnosis were less likely to have a history of mental health treatment.Conclusions: This is the first study to demonstrate unmet mental health need in a large sample of children with CPS and PGE. The study's findings suggest that parents and clinicians should be aware of the mental health needs of children with epilepsy, particularly if they have one or more of the identified risk factors.
Postictal Psychosis in Temporal Lobe Epilepsy
Authors: Leutmezer Fritz , Podreka Ivo , Asenbaum Susanne , Pietrzyk Uwe , Lucht Helmut , Back Claude , Benda Norbert , Baumgartner Christoph 
Published: December 2004

Summary:  Purpose: Postictal psychosis is a well‐known complication, occurring especially in patients with temporal lobe epilepsy. It usually runs a benign course. The literature on this topic is sparse, and the underlying pathogenic mechanisms are not known.Methods: We report five patients with temporal lobe epilepsy in whom postictal psychosis developed during the course of video‐EEG monitoring; they were studied with hexamethyl‐propyleneamine‐oxime single‐photon emission computed tomography (HMPAO‐SPECT) during and after the psychotic event.Results: In comparison to the interictal state, all SPECT scans obtained during postictal psychosis were remarkable for bifrontal and bitemporal hyperperfusion patterns. Some studies also demonstrated unilateral left lateral frontal hyperperfusion. These cortical blood‐flow patterns appeared to be distinct from those obtained during complex partial seizures.Conclusions: Our data suggest that postictal psychoses in patients with temporal lobe epilepsy are associated with hyperactivation of both temporal and frontal lobe structures. This hyperperfusion may reflect ongoing (subcortical) discharges, active inhibitory mechanisms that terminate the seizure, or simply a dysregulation of cerebral blood flow.
Heterogeneous Changes of Monophasic Action Potential Induced by Sustained Stretch in Atrium
Authors: BABUTY DOMINIQUE , LAB MAX 
Published: December 2004

Atrial Monophasic Action Potential and Stretch. Introduction: Chronic enlargement of atrium is common in atrial fibrillation, and the effects of stretch on atrial action potentials seem inconsistent. As atrial muscle is heterogeneous, we suggest that atrial stretch induces a variable electrophysiologic response and that the effects of stretch are only partially mediated by stretch‐activated channels. Methods and Results: Sixteen guinea pig hearts were perfused by the Langendorff method using Kreb's solution with and without 80 μM streptomycin, which is a stretch‐activated channel blocker. Suction electrodes were used to record monophasic action potentials (MAPs) of the left atrium. Left auricular pressure was monitored by a balloon. We determined the MAP duration at 50% and 90% repolarization (MAPD50 and MAPD90) in basal conditions and after a slow onset but sustained stretch of the atrium in the absence and presence of streptomycin. Stretch induced no overall consistent or significant change in mean MAPD50 and MAPD90. The individual responses were markedly variable. The most frequent response (about 50%) was a decrease in MAPD50 and MAPD90. In 25% of cases, there was no change, and in 25% we observed increases in MAPD50 and MAPD90. Streptomycin did not affect MAPD50 and MAPD90, but it dramatically modified the distribution of MAPD changes induced by stretch. In particular, streptomycin removed stretch‐induced shortening of MAPD50 and MAPD90, whereas it did not affect stretch‐induced lengthening. Conclusion: Sustained stretch of atrium induces variable modifications of MAPD that are only partially inhibited by streptomycin. This suggests the participation of ionic channels other than specific stretch‐activated channels in the response of atrial myocardium to sustained stretch.
Exact Solutions to a Class of Linearized Magnetohydrodynamic Flow Problems
Authors: Levy R. H. 
Published: December 2004

A general discussion of the properties of magnetohydrodynamic flows at low conductivity is given, and then attention is restricted to the class satisfying the following conditions: (a) The flow is steady, two-dimensional, inviscid, and only slightly perturbed from uniform conditions. (b) The magnetic field vector is also two-dimensional and lies in the plane of the flow. (c) The distortion of the applied field by the induced currents is negligible. (d) Physical boundaries on the flow are one or two infinite plates parallel to the flow direction. (e) The conductivity of the fluid is a scalar quantity, but may vary in a restricted manner with position.
With these assumptions, the perturbations to the flow are calculated exactly for arbitrary magnetic fields for the cases in which the undisturbed flow is either incompressible or supersonic. Illustrative examples for simple magnetic fields are evaluated; for some of these examples the subsonic case is also treated. Another particular example is used to show the effect of spatially varying conductivity on the flow. The limits of the applicability of these results are discussed, and general conclusions regarding the nature of the flow perturbation are drawn.
Existence of Detonations for Large Values of the Rate Parameter
Authors: Wood W. W. 
Published: December 2004

Recent investigations of idealized Navier-Stokes detonation structure have left unresolved the existence and nature of flow solutions in the case of very fast reactions. By formulating the problem explicitly in terms of a specified initial state and a specified hot boundary mass velocity wP (relative to the unreacted explosive), it is shown that suitable ``steady'' flows exist in all cases, providing that a rarefaction wave or a slower moving shock wave is allowed to follow the detonation front.
An initial-state parameter Γ0, involving the reaction-rate ``pre-exponential factor'' and the thermal conductivity, is defined, as well as an associated critical value Γu(CJ), which depends on the heat capacity ratio, and the enthalpy and activation energy of the reaction. If Γ0 &lt; Γu(CJ), then for small wP the predicted flow is the Chapman-Jouguet (CJ) detonation followed by a rarefaction. As wP is increased through the CJ mass velocity wC J, the flow changes continuously to increasingly overdriven detonations. If Γ0 &gt; Γu(CJ), then for small wP the predicted flow is a weak detonation whose velocity D depends on Γ0, followed by a rarefaction. As wP is increased through the corresponding weak detonation mass velocity w(Γ0), the flow becomes the same weak detonation followed by a slower moving shock wave. With continued increase of wP this shock velocity increases until, at a certain value of wP, it becomes equal to the weak detonation velocity. At still larger wP, the flow changes continuously into an overdriven strong detonation.
Both unimolecular and bimolecular kinetics are considered. So-called ``reasonable'' values of the unimolecular parameters lead to the possibility of the flows involving weak detonations, but as noted by Hirschfelder, Curtiss, et al., the conditions are then such as to require a quasi-unimolecular mechanism to become bimolecular, due for example to depletion of the activated state. When bimolecular kinetics are considered, reasonable parameter values appear to exclude the weak detonation flows.
Impossible Shadows and Lightness Constancy
Authors: Soranzo Alessandro , Agostini Tiziano 
Published: December 2004

The intersection between an illumination and a reflectance edge is characterised by the ‘ratio-invariant’ property, that is the luminance ratio of the regions under different illumination remains the same. In a CRT experiment, we shaped two areas, one surrounding the other, and simulated an illumination edge dividing them in two frames of illumination. The portion of the illumination edge standing on the surrounding area (labelled contextual background) was the contextual edge, while the portion standing on the enclosed area (labelled mediating background) was the mediating edge. On the mediating background, there were two patches, one per illumination frame. Observers were asked to adjust the luminance of the patch in bright illumination to equate the lightness of the other. We compared conditions in which the luminance ratio at the contextual edge could be (i) equal (possible shadow), or (ii) larger (impossible shadow) than that at the mediating edge. In addition, we manipulated the reflectance of the backgrounds. It could be higher for the contextual than for the mediating background; or, vice versa, lower for the contextual than for the mediating background. Results reveal that lightness constancy significantly increases when: (i) the luminance ratio at the contextual edge is larger than that at the mediating edge creating an impossible shadow, and (ii) the reflectance of the contextual background is lower than that of the mediating one. We interpret our results according to the albedo hypothesis, and suggest that the scission process is facilitated when the luminance ratio at the contextual edge is larger than that at the mediating edge and/or the reflectance of the including area is lower than that of the included one. This occurs even if the ratio-invariant property is violated.
Chancery's ‘Younger Sister’: the Court of Exchequer and its Equity Jurisdiction, 1649–1841*
Authors: Horwitz Henry 
Published: December 2004

Abstract
An analysis of Exchequer equity litigation (subject‐matter, parties and procedures), in part by comparison to Chancery. The analysis identifies general similarities as well as some particular features of Exchequer process that help to account the preference of some litigants (or their legal advisers) for pursuing their disputes in Exchequer rather than in Chancery.
William Law and Cambridge Jacobitism, 1713–16
Authors: Starkie Andrew 
Published: December 2004

Abstract
The case of William Law, a Cambridge fellow and high–profile Jacobite, illustrates the character of Jacobitism in the universities and opposition to it at the time of the Utrecht treaty negotiations. This article outlines Law's political beliefs and university career, and suggests that, although Law was disciplined for his vocal Jacobitism, he was not politically isolated, but had support from others with influence in the university. Law's decision to refuse the oaths of allegiance and abjuration in 1715 set him apart from other tories in the university, not because of political ideology or dynastic allegiance, but because of conscience.
Report on the Workshop on Practical Protection in Humanitarian Crises
Authors: Moller Elizabeth , Fagen Patricia Weiss , Martin Susan 
Published: December 2004

With a global crisis of approximately 15 million refugees and an estimated 20 to 25 million internally displaced persons (IDPs) in need of protection, the current protection regime is under increased scrutiny. “Practical Protection” is a fairly new concept. Those pursuing it aim to expand understanding and responsibilities for protection beyond those institutions with a specific protection mandate. “The Workshop on Practical Protection in Humanitarian Crises” was organized to bring the practical protection concept to representatives from a wide range of international agencies, governmental agencies and non‐governmental organizations (NGOs), who discussed its implications for their work in humanitarian crises.Organizations with specific protection mandates, primarily the United Nations High Commissioner for Refugees (UNHCR) and the International Committee for the Red Cross (ICRC), work to protect uprooted groups through legal tools and recognized principles, often in the context of assistance programmes that provide shelter, food, water, medical care, education and other forms of humanitarian assistance. They work in collaboration with NGOs and other international organizations that focus primarily on assisting forced migrants. These latter agencies have traditionally avoided overt involvement in protection activities. When UNHCR and ICRC are not present or are over‐extended, gaps in the protection regime emerge. The gap is particularly evident with regard to internally displaced and other war‐affected populations, but it is present in most refugee situations as well.