bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Gly482Ser variant of the PPARGC1 gene is associated with Type 2 diabetes mellitus in northern Chinese, especially men
Authors: Sun L. , Yang Z. , Jin F. , Zhu X. Q. , Qu Y. C. , Shi X. H. , Wang L. 
Published: August 2006

AbstractAims  To investigate the prevalence of the Gly482Ser polymorphism of the PPARGC1 gene in a northern Chinese population and to clarify the susceptibility of individuals with the Gly482Ser polymorphism to insulin resistance and related diseases.Methods  We studied the association of the Gly482Ser polymorphism identified in the PPARGC1 gene with Type 2 diabetes mellitus (T2DM) in 390 unrelated patients with T2DM and 525 control subjects with normal glucose tolerance. Clinical parameters and measures of insulin resistance were recorded. Genotypes were determined by the polymerase chain reaction—restriction fragment length polymorphism (PCR‐RFLP) method, which was further confirmed by direct sequencing in 20 randomly selected cases.Results  The Gly482Ser polymorphism was common in the northern Chinese population. Univariate analysis indicated no statistically significant differences in allele frequencies or genotype frequencies of the Gly482Ser polymorphism in diabetic and control subjects (minor 482Ser allele frequency 44.4 vs. 41.4%, P = 0.169). However, logistic regression analysis demonstrated a positive 1.645‐fold higher risk of the Ser/Ser genotype for T2DM (P = 0.039, 95% CI = 1.026–2.632). After stratification by gender, the risk of Type 2 diabetes in men was increased 1.852‐fold (95% CI = 1.125–3.049) in those with the Ser/X genotype compared with those with the Gly/Gly genotype (P = 0.015). No associations were observed between the Gly482Ser polymorphism and parameters of insulin resistance, obesity and hypertension.Conclusion  The Gly482Ser variant of the PPARGC1 gene might contribute to susceptibility to T2DM in northern Chinese subjects. The Ser/X genotype of the Gly482Ser polymorphism in the PPARGC1 gene appears to be a risk factor for T2DM in northern Chinese men.
Coronary calcification, homocysteine, C‐reactive protein and the metabolic syndrome in Type 2 diabetes: the Prospective Evaluation of Diabetic Ischaemic Heart Disease by Coronary Tomography (PREDICT) Study
Authors: Godsland I. F. , Elkeles R. S. , Feher M. D. , Nugara F. , Rubens M. B. , Richmond W. , Khan M. , Donovan J. , Anyaoku V. , Flather M. D. ,   for the PREDICT Study Group
Published: August 2006

AbstractAims  The PREDICT Study aims to determine: (i) the association between cardiovascular risk factors and coronary artery calcification score (CACS) obtained by electron beam tomography and (ii) the predictive value of CACS for coronary heart disease (CHD) events in Type 2 diabetes.Methods  Having previously reported relationships between CACS and conventional risk factors, we have now studied the novel risk factors, plasma high‐sensitivity C‐reactive protein (CRP) and homocysteine, insulin resistance, serum apoprotein A1 and B concentrations, the serum triglyceride/high‐density lipoprotein cholesterol ratio and metabolic syndrome (International Diabetes Federation definition) in 573 subjects of the PREDICT Type 2 diabetes cohort.Results  In univariate analyses, the only significant positive novel correlate of CACS was homocysteine (P = 0.0004). CRP was increased in those with detectable calcification, but decreased with increasing calcification score (P = 0.006). In a multivariate model that included all significant univariate correlates, CACS was independently associated with age (P < 0.0001), waist–hip ratio (P < 0.02), male gender (P < 0.05) and duration of diabetes (P < 0.05), but the association with homocysteine was no longer significant. The negative association between CACS and CRP remained in multivariate analysis, and was independent of statin use.Conclusions  Age was the major factor influencing CACS in Type 2 diabetes, with weaker contributions from waist hip–ratio and duration of diabetes. Other novel cardiovascular risk factors appear to have little positive effect.
Postchallenge glucose rises with increasing age even when glucose tolerance is normal
Authors: Rhee M. K. , Ziemer D. C. , Kolm P. , Phillips L. S. 
Published: August 2006

AbstractAims  Ageing increases the likelihood of developing diabetes, with associated cardiovascular disease. In a cross‐sectional study, we sought to determine whether age is associated with an increase in glucose concentrations 1 h after an oral glucose challenge (1‐h OGTT), even when glucose tolerance is normal (NGT).Methods  Among subjects in the NHANES II database, 2591 subjects with NGT and documented 1‐h OGTT glucose concentrations were studied. The relationship between age and 1‐h OGTT glucose concentrations was assessed in a multivariable linear regression analysis.Results  In a multivariable linear regression analysis, each 10‐year increase in age conferred an additional 0.20 mmol/l increase in the 1‐h OGTT glucose (P < 0.0001). Moreover, an interaction between age and gender was found such that 1‐h OGTT glucose concentrations rose more rapidly with increasing age in men than in women. The impact of age on 1‐h OGTT glucose was independent of both fasting and 2‐h OGTT glucose concentrations.Conclusions  One‐hour OGTT glucose concentrations rise significantly with age even in subjects with NGT. Further investigation is warranted to explore the pathophysiological significance of such age‐related impairment of glucose handling, which might increase the risk of cardiovascular disease even when patients do not meet criteria for the diagnosis of diabetes or prediabetes.
Central Banking by Committee
Authors: Sibert Anne 
Published: August 2006

AbstractA small economics literature on monetary policy making by committee is complemented by the literature on groups in the other social sciences. I review some of this work, focusing on the effect of size on group performance and whether committees are more moderate than individuals. Studies document that an individual's effort decreases with group size unless their contributions can be identified and evaluated and that committee membership is polarizing, tending to make committees more extreme. A particularly harmful form of group polarization occurs when a striving for consensus causes members to stop paying sufficient attention to alternative actions. The literature suggests that monetary policy committees should have a clear objective, publish individual votes and not have many more than five members. They should be structured so that members do not act as part of a group, perhaps by having short terms in office and members from outside the central bank. External scrutiny of the decision‐making process should be encouraged.
Genetic structure within and among regional populations of the Eurasian badger (Meles meles) from Denmark and the Netherlands
Authors: Van de Zande L. , Van de Vliet M. , Pertoldi C. , Loeschcke V. , Müskens G. , Bijlsma R. 
Published: August 2006

AbstractThe Eurasian badgerMeles meleshas a wide distribution area ranging from Japan to Ireland. In western Europe badger habitats are severely disturbed by anthropogenic factors, leading to fragmentation into subpopulations and formation of a metapopulation substructuring of once continuous panmictic populations. We have examined the genetic structure of Dutch and Danish badger populations on a relatively small scale (within countries) and a larger scale (between countries). The levels of genetic variation of populations were moderate and did not differ significantly among populations (overallHO=0.30, overallHE=0.34). Considerable genetic differentiation between the Dutch and Danish populations was found (overallFST=0.32, mean pairwise Dutch–DanishFST=0.42), indicating a large‐scale substructuring of these western European badger populations. Further analysis showed that the Danish badger population can be substructured into three clusters [P(k=3)=0.99], but the Dutch populations cluster into one more or less panmictic population [P(k=1)=0.99] with little or no substructuring. The presence of migration barriers, such as roads, together with the peninsular geography of Denmark, may have led to this structuring of badger populations. In contrast, measures that improve migration and connection to other populations from neighboring countries may have prevented substructuring of the Dutch badger population.
Growth and sexual dimorphism in a population of hybrid macaques
Authors: Schillaci M. A. , Froehlich J. W. , Supriatna J. 
Published: August 2006

AbstractGrowth and sexual dimorphism have long been the focus of investigation for researchers interested in the life history and socioecology of nonhuman primates. Previous research has shown that sex differences in the duration of growth, or bimaturism, are primarily responsible for the sexual dimorphism observed in anthropoid primates with multimale–multifemale social structure, such as macaques. The present study investigates sex differences in patterns of craniofacial and somatometric growth relative to head and body size and relative to dental development in a population of hybrid macaques (Cercopithecidae: Macaca) from Sulawesi, Indonesia. How these patterns may contribute to sexual dimorphism in this hybrid population is also examined. The results of the study suggest that there is no substantial effect on the levels of sexual dimorphism associated with hybridization in these macaques. Although sex differences in patterns of size‐related, or allometric, growth patterns play a significant role in the development of sexual dimorphism for some cranial dimensions in these hybrids, bimaturism seems to be the primary component in the ontogeny of sexual dimorphism in this hybrid population. The observed levels of hybrid dimorphism and the predominant ontogenetic pattern of bimaturism characterized by prolonged male growth are consistent with previously published reports on dimorphism and growth in other cercopithecine primates.
Habitat selection and feeding ecology of the cheetah (Acinonyx jubatus) in thicket vegetation: is the cheetah a savanna specialist?
Authors: Bissett C. , Bernard R. T. F. 
Published: August 2006

AbstractHabitat selection and feeding ecology of a reintroduced population of cheetahs Acinonyx jubatus were studied in a 16 000 ha game reserve in the Eastern Cape Province (South Africa). Seventy per cent of the reserve is characterized by very dense thicket vegetation (valley bushveld) and the remainder is open and savanna‐like. The results illustrated a strong effect of sex and group size on the behaviour of cheetahs. The coalition (three adult males) killed significantly larger animals (55% of kills weighed more than 65 kg) than single female cheetahs (less than 2% of kills weighed more than 65 kg). Female cheetahs showed temporal and spatial avoidance of lions by hunting at dawn and dusk and positioning their home ranges [95% utilization distribution (UDs)] significantly farther from the pride of lions than did the coalition. The coalition hunted earlier and later than female cheetahs, and 46% of their kills were made in darkness. In addition, their home range overlapped that of the lions and they showed neither temporal nor spatial avoidance of the lions. The rates of kleptoparasitism were lower and the kill retention times were longer than those reported elsewhere in Africa, and it is suggested that this is a consequence of the cover provided by the thicket vegetation and prey size. The home ranges (95% UDs) of female cheetahs incorporated more thicket vegetation than that of the coalition, indicating that the coalition is less susceptible to predation than single females. These data suggest that cheetahs possess greater behavioural flexibility than previously reported, that they can hunt successfully in thicket vegetation, sometimes in darkness, that they are not restricted to killing small to medium‐sized prey, and that they may not be savanna specialists.
Allometry of egg and hatchling mass in birds and reptiles: roles of developmental maturity, eggshell structure and phylogeny
Authors: Deeming D. C. , Birchard G. F. 
Published: August 2006

AbstractThe factors determining hatchling mass (HM) are investigated in a wide range of birds and reptiles using regression analysis, analysis of covariance and comparative analysis by independent contrasts. In birds, initial egg mass (IEM) at laying is the most important factor affecting HM and phylogenetic relatedness has no significant effects on HM. Developmental maturity of the avian neonates did not affect the proportion of IEM converted into HM. For all reptile species, IEM also significantly affected HM but phylogenetic relatedness did not. By contrast, allometric relationships between IEM and HM in the different orders of reptiles were affected by shell type. The robustness of allometric relationships across taxa in birds and reptiles suggests that there is a physiological link between IEM and HM, which contrasts with that observed for the relationship between egg mass and incubation period. This result has significant implications for the inter‐relationships between IEM and embryonic growth, which are discussed for birds and reptiles.
Cyanobacterial calcification and its rock‐building potential during 3.5 billion years of Earth history
Authors: ALTERMANN W. , KAZMIERCZAK J. , OREN A. , WRIGHT D. T. 
Published: August 2006

ABSTRACTMicrobially mediated calcification can be traced back for at least 2.6 billion years. Although morphological comparison of fossil and recent microbial carbonates suggests that mineralization processes associated with cyanobacteria and their interactions with heterotrophic bacteria have remained similar from the Archaean until today, the metabolic and chemical details remain poorly constrained. Microbial consortia often exhibit an ability to change solution chemistry and control pH at the microscale, passively or actively. This leads to oversaturation of Ca2+ and ions and to the removal of kinetic inhibitors to carbonate precipitation, like sulphate or phosphate. The kinetic barriers of low carbonate ion activity, ion hydration and ion complexing, especially in saline waters, inhibit spontaneous carbonate mineral precipitation from saturated solutions but oxygenic photosynthesis and sulphate reduction by sulphate‐reducing bacteria can overcome these natural barriers. Sulphate in seawater tends to form pairs with Ca2+ and Mg2+ ions. The removal of sulphate reduces complexing, raises carbonate alkalinity, and along with pyrite formation, enhances carbonate precipitation. Cyanobacteria can store Ca2+ and Mg2+ ions in organic envelopes and precipitate carbonates within their sheaths and extracellular polymeric substances, thus, triggering sedimentary carbonate production. We propose that this interplay of cyanobacteria and heterotrophic bacteria has been the major contributor to the carbonate factory for the last 3 billion years of Earth history.
The fate of the homoctenids (Tentaculitoidea) during the Frasnian–Famennian mass extinction (Late Devonian)
Authors: BOND DAVID 
Published: August 2006

ABSTRACTThe homoctenids (Tentaculitoidea) are small, conical‐shelled marine animals that are among the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian–Famennian (F‐F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian–Famennian boundary sections have been studied, in Poland, Germany, France, and the USA. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian ‘Upper Kellwasser Event’. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F‐F extinction. Most notable is the sudden demise of a group, which had been present in rock‐forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here.
Oxygen isotopic composition of sulfate in deep sea pore fluid: evidence for rapid sulfur cycling
Authors: TURCHYN A. V. , SIVAN O. , SCHRAG D. P. 
Published: August 2006

ABSTRACTWe present new data of oxygen isotopes in marine sulfate (δ18OSO4) in pore fluid profiles through organic‐rich deep‐sea sediments from 11 ODP sites around the world. In almost all sites studied sulfate is depleted with depth, through both organic matter oxidation and anaerobic methane oxidation. The δ18OSO4 increases rapidly near the top of the sediments, from seawater values of 9 to maxima between 22 and 25, and remains isotopically heavy and constant at these values with depth. The δ18OSO4 in these pore fluid profiles is decoupled from variations in sulfur isotopes measured on the same sulfate samples (δ34SSO4); the δ34SSO4 increases continuously with depth and exhibits a shallower isotopic increase. This isotopic decoupling between the δ34SSO4 and the δ18OSO4 is hard to reconcile with the traditional understanding of bacterial sulfate reduction in sediments. Our data support the idea that sulfate or sulfite and water isotopically exchange during sulfate reduction and that some of the isotopically altered sulfur pool returns to the environment. We calculate that the rapid increase in the δ18OSO4 in the upper part of these sediments requires rates of this oxygen isotope exchange that are several orders of magnitude higher than the rates of net sulfate reduction calculated from the sulfate concentration profiles and supported by the δ34SSO4. We suggest several mechanisms by which this may occur, including ‘net‐zero’ sulfur cycling, as well as further experiments through which we can test and resolve these processes.
Biodiversity from a historical geology perspective: a case study from Marajó Island, lower Amazon
Authors: ROSSETTI D. F. , DE TOLEDO P. M. 
Published: August 2006

ABSTRACTAssessing patterns of abundance and distribution of Amazonian species is still an overwhelming task that requires integration of multiple disciplines. This work is based on background information gathered from previous reconstructions of the geological history of the lower Amazon drainage basin, in order to analyse biodiversity patterns within the context of landscape transformation. A highly dynamic geological scenario is depicted for this area during the Plio‐Pleistocene and Holocene, which consisted of a large palaeovalley formed as a response of tectonic reactivation. This palaeovalley was filled with sediments transported by a north/northwest orientated palaeo‐Tocantins River. The palaeodrainage became abandoned as the main river course was deviated to the northeast, initiating the separation of Marajó Island from mainland. Geology had a direct impact on the modern physiognomy, with open vegetation dominating in areas with Holocene sedimentation, while closed forests prevailing in older Quaternary and, probably also, Pliocene terrains. Data from fossil and modern mammalian groups indicate the connection of Marajó Island to the mainland during the Last Glacial Maximum, when open vegetation seems to have dominated. Tectonic subsidence was responsible for the maintenance of this vegetation pattern on the eastern side of the Marajó Island, keeping it as a habitat favourable for savanna adapted faunal elements. Based on this kind of information, this work attempts to highlight the importance of integrating studies combining geological and biological events as the key to understand biodiversity patterns in Amazonia. It is expected to open new lines of research dealing with the comprehension of ecology, species and genetic diversity, biogeography, evolutionary scenarios, and speciation mechanisms.
An eastern Tethyan (Tibetan) record of the Early Jurassic (Toarcian) mass extinction event
Authors: WIGNALL P. B. , HALLAM A. , NEWTON R. J. , SHA J. G. , REEVES E. , MATTIOLI E. , CROWLEY S. 
Published: August 2006

ABSTRACTA record of the Early Jurassic mass extinction event is reported from eastern Tethyan (Tibetan) locations for the first time. In the Mount Everest region a thick Lower Jurassic carbonate formation, here named the Yungjia Formation, is developed within the predominantly clastic Triassic–Jurassic succession. Within the formation a sharp transition from peloidal packstones/grainstones to thin‐bedded, pyritic micrite‐shales interbeds records a sharp pulse of deepening and development of dysoxic bottom waters. Both the lithiotid bivalves and the lituolid foraminifera are important constituents of the lower Yungjia Formation but they disappear at this flooding surface or a short distance below it. This extinction event is comparable to that seen at the base of the Pliensbachian/Toarcian boundary in western Tethyan platform carbonates but the Tibetan events occurred late in the Toarcian Stage as indicated by nannofossil biostratigraphy and C isotope chemostratigraphy. The Early Jurassic extinction event (and the associated spread of oxygen‐poor waters) was therefore not synchronous throughout the Tethyan region.
A reactive MILP approach to the multidepot heterogeneous fleet vehicle routing problem with time windows
Authors: Dondo Rodolfo , Cerdá Jaime 
Published: August 2006

AbstractThe time‐window‐constrained vehicle routing problem (VRPTW) is a well‐known combinatorial problem. Its goal is to discover the best set of routes for a vehicle fleet in order to service a given number of customers at minimum cost. Vehicle capacity, maximum service time and time‐window constraints must be satisfied. Most proposed VRPTW optimizing approaches intend to discover the best or a near‐optimal solution at once. Improvement methods are old strategies that apply heuristics to insert customers into tours and/or rearrange nodes to obtain better routes. They are performed until no further improvement is achieved. Little research has been focused on model‐based reactive approaches seeking a better solution by exploring a small solution space around the current solution. This work presents a new model‐based improvement methodology for the multi‐depot heterogeneous‐fleet VRPTW problem to enhance an initial solution through solving a series of MILP mathematical problems that allow exchanges of nodes among tours and node reordering on every route. By restricting the range of improvement options, the problem size can be bounded and a limited number of binary variables is required for real‐world problems. The improvement formulation is based on a continuous time‐domain representation that handles assignment and sequencing decisions through different sets of binary variables and uses the notion of a generalized predecessor instead of a direct predecessor. Several types of VRPTW problems have been efficiently solved.
On‐orbit servicing: a time‐dependent, moving‐target traveling salesman problem
Authors: Bourjolly Jean‐Marie , Gurtuna Ozgur , Lyngvi Aleksander 
Published: August 2006

AbstractThe robotic capability of maintaining and repairing space assets, on‐orbit servicing (OOS), has the potential to change the way spacecraft are designed, manufactured and operated. The most common OOS mission concept envisions an orbital “depot”, where consumables and spare parts for spacecraft will be stored. A “servicing platform”, based at this depot, will be used to service a number of client spacecraft and then return to the depot for resupply. We model OOS as a time‐dependent, moving‐target traveling salesman problem and present an algorithm for minimizing the total amount of energy or time required for OOS operations.