bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lidar remote sensing of above‐ground biomass in three biomes
Authors: Lefsky Michael A. , Cohen Warren B. , Harding David J. , Parker Geoffrey G. , Acker Steven A. , Gower S. Thomas 
Published: March 2003

AbstractEstimation of the amount of carbon stored in forests is a key challenge for understanding the global carbon cycle, one which remote sensing is expected to help address. However, estimation of carbon storage in moderate to high biomass forests is difficult for conventional optical and radar sensors. Lidar (lightdetection andranging) instruments measure the vertical structure of forests and thus hold great promise for remotely sensing the quantity and spatial organization of forest biomass. In this study, we compare the relationships between lidar‐measured canopy structure and coincident field measurements of above‐ground biomass at sites in the temperate deciduous, temperate coniferous, and boreal coniferous biomes. A single regression for all three sites is compared with equations derived for each site individually. The single equation explains 84% of variance in above‐ground biomass (P < 0.0001) and shows no statistically significant bias in its predictions for any individual site.
Range size and environmental calcium requirements of British freshwater gastropods
Authors: Briers Robert A. 
Published: March 2003

ABSTRACTCalcium is an essential requirement for the successful growth and development of gastropod molluscs. Data for British freshwater gastropods were used to examine the relationship between environmental calcium requirements and British and European range sizes. At both spatial scales calciphile species, which require a high level of environmental calcium, had significantly smaller range sizes than species able to exploit a wide range of environmental calcium levels. However, at least in Britain, range size may also be influenced by the availability of suitable habitat. British and European range sizes were significantly correlated. This study provides evidence for niche‐based explanations of range size variation, and suggests that both niche breadth and niche availability are important in determining range size.
Genetic control of lipoprotein phenotypes in the laboratory opossum, Monodelphis domestica
Authors: Rainwater David L. , Kammerer Candace M. , Singh Amareshwar T. K. , Moore Perry H. , Poushesh Mahmood , Shelledy Wendy R. , VandeBerg Jane F. , Robinson Edward S. , VandeBerg John L. 
Published: March 2003

AbstractIntroduction  Monodelphis (Monodelphis domestica) shows 20‐fold differences, that may be under genetic control, in individual responses to a high‐fat challenge diet.Materials and methodsTwo partially inbred lines of animals were derived by selectively breeding among high responders and low responders and we analysed data from these pedigreed animals and their F1 progeny. A blood sample was taken from each animal while consuming the basal diet (basal sample). Each animal was then fed a high‐fat, high‐cholesterol challenge diet for 8 weeks prior to collection of a second blood sample (challenge sample). Lipoprotein measurements included cholesterol concentrations of high‐density lipoproteins (HDL‐C) and low‐density lipoproteins (non‐HDL‐C) and particle size phenotypes for both.ResultsQuantitative genetic analyses indicated strong heritabilities (range, 0.382–0.827) for each of the eight traits. We also tested for single genes with large effects on each trait (major genes). Segregation analyses provided evidence of major genes for three traits: basal non‐HDL‐C, challenge non‐HDL‐C, and challenge HDL‐C; no major genes were detected for the lipoprotein size traits. Tests for pleiotropy, using bivariate one‐locus segregation analyses, showed that the major locus for challenge HDL‐C had no effect on the basal HDL‐C and that the major locus for challenge non‐HDL‐C had no effect on basal non‐HDL‐C. However, the major gene for basal non‐HDL‐C did significantly influence challenge non‐HDL‐C.ConclusionWe have found evidence for at least three genes influencing lipoprotein phenotypes under two dietary regimes. Identification of these genes may provide valuable insights into lipoprotein metabolism in other species, including man.
The freshwater fish of Neogene Africa (Miocene–Pleistocene): systematics and biogeography
Authors: Stewart Kathlyn M 
Published: March 2003

AbstractWhile the modern freshwater fish fauna of Africa has been the subject of considerable biological attention, there are few studies on the biogeography that include recent fossil reports. Since the publication of comprehensive reviews of Cenozoic freshwater fish faunas in Africa by Greenwood in the mid 1970s and updates in the late 1970s by Van Couvering, considerable collection and reporting of Cenozoic Africa fish has occurred. These specimens and reports have provided a considerable database from which to derive zoogeographical and biogeographical inferences. A pan‐African fish fauna can be documented at the generic level throughout the Miocene in northern, central and eastern Africa, including Protopterus, Polypterus, Labeo, Alestes/Brycinus, Clarias/Heterobranchus, Synodontis, and Lates. The extinct genus Semlikiichthys (formerly Lates) may also be included in this pan‐African fauna. Where the Miocene fish records were widely distributed through much of the African continent and were primarily fluvial‐derived faunas, the Early Pliocene record is strictly a central and eastern one, mainly from lacustrine deposits. These reflect the new lacustrine habitats created through severe tectonic change, in the form of rifting and volcanism. The Pliocene faunas are characterised both by extinct taxa not previously recorded, and by immigrant taxa. By the Pleistocene the Rift systems were completely formed. However, ongoing volcanism and tectonics continued to alter the hydrological systems. In the Early and Middle Pleistocene, Lakes Albert and Edward both still had the widespread modern genera Lates and Synodontis, and several taxa known from previous deposits. However, all extinct taxa had disappeared, except Sindacharax (Characidae), which was still found in Lake Edward. In the Turkana Basin, there is continuity of most taxa from the Pliocene (except for Semlikiichthys, which is absent), as well as Miocene and Pliocene Sindacharax species. In the Middle Pleistocene, Sindacharax disappears from the African fossil record. Also, in the Pleistocene, several hydrological systems lose their pan‐African faunas, including Lake Edward, Lake Victoria and the Maghreb. The modern faunas are not as diverse at the family level as previously. This history of the Neogene African fish fauna is necessarily incomplete without fossil records from many regions of Africa, particularly in the west and south.
Reconciling sustainability, economic efficiency and equity in fisheries: the one that got away?
Authors: Cochrane Kevern L 
Published: March 2003

AbstractConcern about the global state of fisheries and fish resources has highlighted the three primary considerations in fisheries management: sustainable utilisation, economic efficiency and equity in access to resources. We appear to be failing in pursuit of all three goals. Living marine resources are particularly threatened by overfishing, leading to many of the world’s fish stocks being heavily, fully or over exploited. Similarly, the economic diagnosis is that costs of fishing exceeded the value of the world’s catch by about US$ 40 billion at the beginning of the decade. Statistics on equity are less available, but the necessary spread of limited access to fisheries frequently has the greatest impact on the small scale, traditional fisher.This paper considers the reasons underlying the general failure of fisheries management and the solutions that are being proposed. Factors contributing to the problems include high biological uncertainty, conflict between the constraint of sustainability and social and economic priorities, poorly defined objectives, and institutional failures related to access rights and participation in management by the users. These issues point to the real complexity of fisheries management. It is argued that this complexity can be abused by all interest groups to avoid responsibility and to suit their own objectives. It is suggested that there are eight simple principles controlling fisheries management that are generally well‐understood and, if properly considered in fisheries management systems, would lead to improved performances.Responsible management will, however, only be effective if there is a genuine desire to achieve the objectives. Fishing capacity, frequently reflecting dependency of users on fisheries resources, is commonly in excess of the sustainable production of the resources. Excess dependency can preclude the political will to consider alternative strategies and only once it has been overcome, probably requiring solutions borrowed from outside fisheries, is effective management likely to be considered seriously. Thereafter, responsible management requires setting unambiguous objectives and management measures in co‐operation with users and other interest groups. The agreed strategy must be included in legislation to ensure transparency and accountability and to constrain decision‐makers. The performance of the strategy must be monitored and revised as necessary.
Broadbill swordfish: status of established fisheries and lessons for developing fisheries
Authors: Ward P. , Porter J.M. , Elscot S. 
Published: March 2003

Guidelines for the assessment and management of developing swordfish fisheries are derived through an examination of five swordfish fisheries. As they develop, swordfish fisheries may be inclined to local depletion around underwater features, such as seamounts and banks. Few nations have applied the precautionary approach in managing their developing swordfish fisheries. Without controls, swordfish fisheries expand geographically and fishing effort increases, often overshooting optimum levels. However, it is difficult to distinguish clear evidence of fishery collapse; modern longliners harvest widely distributed tuna and swordfish and they are able to relocate to distant areas or switch between target species in response to fluctuations in species abundance and price. Furthermore, the wide distribution of swordfish combined with year‐round spawning and high growth rates amongst juveniles probably contribute to the apparent resilience of swordfish stocks to intensive harvesting.Over half the world’s swordfish catch is taken as an incidental catch of longliners fishing for tuna. In several areas, such as the North Atlantic, catch quotas have sometimes caused tuna longline fishers to discard swordfish. Minimum size limits have also resulted in discarding of swordfish in tuna fisheries and in dedicated swordfish fisheries. In addition to weakening the effectiveness of those management measures, bycatch and discarding add to the complexities of managing swordfish fisheries and to uncertainties in assessing the stocks.Longliners that target swordfish often fish at high latitudes where interactions with marine wildlife, such as seabird, are generally more frequent than at low latitudes. Concern over incidental catches of marine wildlife and other species is becoming a driving force in the management of several swordfish fisheries. Fishery management organisations will need to implement management measures to protect non‐target species and gather reliable data and information on the situation by placing observers on boats fishing for swordfish.
Ecological effects of regime shifts in the Bering Sea and eastern North Pacific Ocean
Authors: Benson Ashleen J , Trites Andrew W 
Published: March 2003

AbstractLarge‐scale shifts occurred in climatic and oceanic conditions in 1925, 1947, 1977, 1989 and possibly 1998. These shifts affected the mix and abundance of suites of coexisting species during each period of relative environmental stability—from primary producers to apex predators. However, the 1989 regime shift was not a simple reversal of the 1977 shift. The regime shifts occurred abruptly and were neither random variations nor simple reversals to the previous conditions. Timing of these anomalous environmental events in the North Pacific Ocean appears to be linked to physical and biological responses in other oceanic regions of the world. Changes in the atmospheric pressure can alter wind patterns that affect oceanic circulation and physical properties such as salinity and depth of the thermocline. This, in turn, affects primary and secondary production. Data from the North Pacific indicate that regime shifts can have opposite effects on species living in different domains, or can affect similar species living within a single domain in opposite ways. Climatic forcing appears to indirectly affect fish and marine mammal populations through changes in the distribution and abundance of their predators and prey. Effects of regime shifts on marine ecosystems are also manifested faster at lower trophic levels. Natural variability in the productivity of fish stocks in association with regime shifts indicates that new approaches to managing fisheries should incorporate climatic as well as fisheries effects.
The effect of aspirin, ticlopidine and their low‐dose combination on platelet aggregability in acute ischemic stroke: a short duration follow‐up study
Authors: Akyüz Aytekin , Bolayir Ertugrul , Dener Sefik , Topalkara Kamil , Topaktas Suat 
Published: March 2003

We investigated the effects of aspirin (300 mg/d), ticlopidine (500 mg/d) and their low‐dose combination (aspirin 100 mg/d plus ticlopidine 250 mg/d) on the platelet aggregability using the Wu and Hoak method. Each treatment group consisted of 25 patients with acute ischemic stroke. Platelet aggregation ratios (PAR) were measured on the 1st (before treatment), 10th and 90th days in the treatment groups and compared with those of 25 control cases. On the first day, comparison of PAR in each treatment group with the control was significant, while the differences between treatment groups were not significant. On the 90th day, differences of PAR between aspirin and control were significant, but differences between the other treatment groups and the control group were not significant, indicating a lower anti‐aggregant efficacy of aspirin.Our study suggests that PAR determination can be used to assess the efficacy of anti‐aggregant drugs. Our crude observation also suggests a higher anti‐aggregant efficacy of ticlopidine, and aspirin plus ticlopidine, than aspirin. In addition, proper doses of aspirin plus ticlopidine may be a good choice for the prevention of ischemic stroke. Further studies are required to assess whether PAR determination could be useful for assessing patients at risk of stroke, and for drug selection for the prevention of stroke.
Electrophysiological measures and dual‐task performance in Tourette syndrome indicate deficient divided attention mechanisms
Authors: Johannes S. , Wieringa B. M. , Nager W. , Müller‐Vahl K. R. , Dengler R. , Münte T. F. 
Published: March 2003

Tourette syndrome has been associated with impairments of attentional functions such as distractability, even in subjects without co‐morbid attention deficit hyperactivity disorder. Based on the results of earlier research we hypothesized that Tourette syndrome patients might employ altered control mechanisms of attentional processes and have concurrent difficulties in allocating their attentional resources among competing tasks.Event‐related brain potentials (ERPs) were recorded in a group of Tourette syndrome patients and in a matched control group during a dual task experiment. This experiment required the simultaneous detection of visual and auditory target stimuli which were manipulated to yield two different difficulty levels each of which were varied orthogonally. The behavioural parameters confirmed the intended performance differences between difficult‐to‐detect targets and easy‐to‐detect targets. This was paralleled by lower amplitudes and longer latencies of the corresponding P3b‐ERP subcomponents. Although Tourette syndrome patients were unimpaired in overall performance they showed an increased interference of visual task demands with auditory target perception. In parallel they also exhibited a reduced amplitude of the P3b component to auditory targets. The findings show that Tourette syndrome patients are not generally impaired in their dual task performance. The allocation of attentional resources to competing tasks however, is altered. We speculate that this may be related to deficient inhibitory functions.
Facial myokymia in brain death
Authors: Saposnik G. , Mauriño J. , Saizar R. 
Published: March 2003

Background Brain death (BD) is the irreversible loss of all functions of the brain and brainstem. Spontaneous and reflex movements of the limbs have been described in this condition. However, facial myokymia (FM) in BD has not been previously reported. The origin of that motor phenomenon in alive patients is still uncertain, since supranuclear, nuclear and peripheral mechanisms have been proposed. Objective We describe the presence of FM in a patient who fulfilled the criteria for BD. A 40‐year‐old‐man had right‐sided weakness and impaired consciousness. After 14 h admission, he fulfilled the criteria for BD. A CT scan of the head showed a large putaminal hemorrhage. The EEG was isoelectric. At that time, fine spontaneous twitches of the left cheek were noticed. They consisted of repetitive and rhythmic movements in groups of 3–5 lasting for <5 s. These movements appeared every 2–10 min during 6 h. Discussion Spinal reflexes have been described in BD. The presence of any movements other than the recognized reflexes may question this diagnosis and limit organ procurement for transplantation. The recognition of FM as an accepted movement in BD patients has practical and legal implications.
On the outcome in stroke patients one year later: the role of atrial fibrillation
Authors: Cisternino M. D. , Giaquinto S. , Maiolo I. , Palma E. , Valeriani M. , Vittoria E. 
Published: March 2003

The post‐stroke aftermath of patients suffering from atrial fibrillation (AF) is investigated. A total of 104 consecutive patients (80 with AF and 24 without AF) were referred to a rehabilitation centre and enrolled. They underwent a rehabilitative programme. Disability was assessed by using the Functional Independence Measure (FIM), at the time of admission, discharge and after 1 year. Death was more frequent over the 1‐year interval in AF group. Ten patients died (42%), whereas in the non‐AF group death occurred in 15 cases (19%). By using chi‐square test, the difference was significant (P < 0.02).The logistic regression analysis indicated that the unique variable affecting the FIM at follow‐up was the FIM at discharge (P < 0.0001). AF was not a significant variable in the equation. The result can be attributed to subject attrition in the AF group, as the most severe patients died and survivors could benefit from a better functional status.
Protective behaviours: a useful approach in working with people with learning disabilities
Authors: Harper Glynis , Hopkinson Peter , McAfee John G. 
Published: March 2003

SummaryThe purpose of this paper is to introduce people working in the field of learning disabilities to the concept of ‘protective behaviours’ (PBs). It suggests that the PBs approach is relevant to people with learning disabilities, particularly in relation to issues of vulnerability and empowerment. The paper briefly overviews the basic features of the PBs approach and provides examples of its application in clinical settings. It concludes that the PBs process is of fundamental importance to services for people with learning disabilities and recommends that professionals would benefit from attending any training opportunities that may arise.
Quartz recrystallization and fluid flow during contact metamorphism: a cathodoluminescence study
Authors: Holness M. B. , Watt G. R. 
Published: March 2003

AbstractCathodoluminescence (CL) images of quartz grains in the Appin Quartzite from the aureole of the Ballachulish Igneous Complex (Scotland) reveal a textural complexity that we interpret in the light of published models of the evolution of the contact aureole. Five distinct generations of quartz can be discriminated in CL. The oldest of these is a dark luminescing mottled quartz (Type 1 quartz) that occurs in the centres of pre‐existing grains, in samples collected from 210 m to 0.1 m from the contact. Dark mottled quartz is interpreted to be unrecrystallized material and has a regional metamorphic CL spectral signature. The onset of contact metamorphism resulted in grain growth visible in CL as a series of fine‐scale alternating bands of bright and dark luminescing material (Type 2 quartz), which we attribute to infiltration of repeated pulses of small amounts of H2O along grain boundaries. Close to the intrusion, a subgrain‐scale network of intragranular, bright luminescing features could have resulted from either intragranular microcrack‐controlled infiltration of H2O at high temperatures or intergranular cracking followed by grain growth (Type 3 quartz). Broad bands of bright material on grain boundaries in samples that are inferred to have undergone partial melting are interpreted as quartz crystallized from the melt phase (Type 4 quartz). The final stage in the textural development is marked by a series of aligned fractures, detected in CL by nonluminescing material (Type 5 quartz) and corresponding closely with trails of fluid inclusions. These fractures are interpreted as the pathways for late‐stage, low‐temperature, retrogressive fluids.
Retrograde P–T evolution and high temperature–low pressure fluid circulation in relation to late Hercynian intrusions: a mineralogical and fluid inclusion study of the Charroux‐Civray plutonic complex (north‐western Massif Central, France)
Authors: Freiberger R. , Boiron M.‐C. , Cathelineau M. , Cuney M. , Buschaert S. 
Published: March 2003

AbstractThe calc‐alkaline plutonic complex from Charroux‐Civray (north‐western part of the French Massif Central) displays multiphase hydrothermal alteration. Plutonic rocks, as well as early retrograde Ca–Al silicate assemblages, which have crystallized during cooling and uplifting of the plutonic series, are affected by multiphase chlorite–phengite–illite–carbonate alteration linked to intense pervasive fluid circulation through microfractures. The petrographic study of alteration sequences and their associated fluid inclusions in microfissures of the plutonic rocks, as well as in mineral fillings of the veins, yields a reconstruction of the P–T–X evolution of the Hercynian basement after the crystallization of the main calc‐alkaline plutonic bodies. This reconstruction covers the uplift of the basement to its exposure and the subsequent burial by Mesozoic sediments.Cooling of the calc‐alkaline plutonic series started at solidus temperatures (∼650°C), at a pressure of about 4 kbar (1 bar = 105 N m−2), as indicated by magmatic epidote stability, hornblende barometry and fluid inclusion data. Cooling continued under slightly decreasing pressure during uplift down to 2–3 kbar at 200–280°C (prehnite–pumpellyite paragenesis). Then, a hot geothermal circulation of CO2‐bearing fluids was induced within the calc‐alkaline rocks leading to the formation of greisen‐like mineralizations. During this stage, temperatures around 400–450°C were still high for the inferred depths (∼2 kbar). They imply abnormal heat flows and thermal gradients of 60–80°C km−1. The hypothesis of the existence of one large or a succession of smaller peraluminous plutons at depth, supported by geophysical data, suggests that localized heat flows were linked to concealed leucogranite intrusions. As uplift continued, greisen mineralization was subsequently affected by the chlorite–phengite–dolomite assemblage, correlated with aqueous and nitrogen‐bearing fluid circulations in the temperature range of 400–450°C. In a later stage, a continuous temperature decrease at constant pressure (∼0.5 kbar) led to the alteration of the dolomite–illite–chlorite type in the 130–250°C temperature range.