bluuebunny/crossref_metadata_2025 huggingface dataset:
NORTH ATLANTIC RIGHT WHALE DISTRIBUTION IN RELATION TO SEA‐SURFACE TEMPERATURE IN THE SOUTHEASTERN UNITED STATES CALVING GROUNDS
Authors: Keller Chérie A. , Ward‐Geiger Leslie I. , Brooks William B. , Slay Christopher K. , Taylor Cynthia R. , Zoodsma Barbara J.
Published: February 2006

Abstract

Standardized aerial surveys were used to document the winter (December–March) distribution of North Atlantic right whales in their calving area off the coasts of Georgia and northeastern Florida (1991–1998). Survey data were collected within four survey zones in and adjacent to federally designated critical habitat. These data, including whale‐sighting locations and sampling effort, were used to describe right whale distribution in relation to sea‐surface temperature (SST) from satellite‐derived images. Locations where whales were sighted (n= 609) had an overall mean SST of 14.3°C ± 2.1° (range 8°–22°C). Data from two survey zones having sufficient data (including the “early warning system” (EWS) zone and the Florida nearshore) were pooled by season and stratified by month to investigate changes in monthly ambient SST and fine‐scale distribution patterns of right whales in relation to SST within spatially explicit search areas. Using Monte Carlo techniques, SSTs and latitudes (means and standard deviations) of locations where whales were sighted were compared to a sampling distribution of each variable derived from daily‐search areas. Overall, results support a nonrandom distribution of right whales in relation to SST: during resident months (January and February), whales exhibited low variability in observed SST and a suggested southward shift in whale distribution toward warmer SSTs in the EWS zone; while in the relatively warmer and southernmost survey zone (Florida nearshore), right whales were concentrated in the northern, cooler portion. Our results support that warm Gulf Stream waters, generally found south and east of delineated critical habitat, represent a thermal limit for right whales and play an important role in their distribution within the calving grounds. These results affirm the inclusion of SST in a multivariate predictive model for right whale distribution in their southeastern habitat.
TAXONOMIC STATUS AND GEOGRAPHICAL CRANIAL VARIATION OF COMMON DOLPHINS (DELPHINUS) IN THE EASTERN NORTH ATLANTIC
Authors: Murphy Sinéad , Herman Jerry S. , Pierce Graham J. , Rogan Emer , Kitchener Andrew C.
Published: February 2006

Abstract

The common dolphin has a widespread distribution and is relatively abundant in the temperate to subtropical waters of the eastern North Atlantic. However, it is not known whether different species, subspecies, or populations occur in this region. We examined 393 common dolphin skulls obtained from both stranded and bycaught individuals collected between 1901 and 2005. The series included skulls of 152 females and 199 males, from animals ranging in body length from 93 to 230 cm and 105 to 244 cm, respectively. The ranges of total body length, skull size, RL/ZGW ratio and maximum upper alveolar (tooth) count of common dolphins in the eastern North Atlantic overlapped with those of both short‐ (D. delphis) and long‐beaked (D. capensis) species found off the Californian coast. However, in the absence of additional data, the common dolphin in the eastern North Atlantic is regarded here as a large form of Delphinus delphis. Sexual dimorphism and possible sex‐linked characters were identified within the sample. Results of the current study indicate some population differentiation within the eastern North Atlantic, with common dolphins off Portugal showing segregation in morphometric characteristics from common dolphins in other areas.
PYGMY SPERM WHALES KOGIA BREVICEPS IN THE NORTHEAST ATLANTIC: NEW INFORMATION ON STOMACH CONTENTS AND STRANDINGS
Authors: Santos M. B. , Pierce G. J. , López A. , Reid R. J. , Ridoux V. , Mente E.
Published: February 2006

Abstract

Little is known about the feeding ecology of pygmy sperm whales (Kogia breviceps) in the Northeast Atlantic. Results are presented on the stomach contents of five whales stranded on the Galician coast (NW Spain) between 1995 and 2002 and seven whales stranded on the French Atlantic coast between 1984 and 2001. These results are compared with those obtained from the stomach contents of two pygmy sperm whales (a pregnant female and her calf ) stranded on the Scottish (UK) coast in 1999, the first records of the species in Scotland. In 13 out of 14 cases, food remains consisted almost entirely of cephalopod beaks, although some crustacean and fish remains were also present. In all the Spanish specimens, the identified prey were oceanic species: the cephalopods Histioteuthis reversa, H. bonnellii, Todarodes sagittatus, the viperfish Chauliodus sloani, and the giant mysid Gnatophausia sp. The same cephalopod species were found in the stomachs of the whales stranded in Scotland, although both whales had also consumed neritic cephalopod species such as Rossia macrosoma and other sepiolids. In the French specimens, almost all prey identified were oceanic cephalopods (H. reversa, Brachioteuthis riseii, T. sagittatus, Taonius pavo, etc.), but remains of crustaceans and a neritic squid (Loligo forbesi) were also found. One whale from France had eaten mainly Henslow's swimming crab (Polybius henslowi). Results from the present study are consistent with those found by other authors in the Azores and the Canary Islands in that pygmy sperm whales appear to be mainly teuthophagous, with histioteuthid squids forming an important part of the diet. Strandings records suggest that occurrence of pygmy sperm whales in the NE Atlantic may be seasonal, with most strandings occurring in autumn and winter.
DEVELOPMENT AND APPLICATION OF A MASS‐ESTIMATION METHOD FOR WEDDELL SEALS
Authors: Ireland Darren , Garrott Robert A. , Rotella Jay , Banfield Jeff
Published: February 2006

Abstract

Traditional methods of acquiring mass data limit the ability to collect large samples from across populations of some pinnipeds, or to sample without great disturbance to the animals. In order to collect substantial samples of mass data from the Weddell seal (Leptonychotes weddellii) population in Erebus Bay, Antarctica, we developed the equipment and methods for estimating the mass of Weddell seals using digital photographs. Resulting regression models predict the mass of adult female seals to within ±13.8% of estimated mass, and ±25.9% of estimated mass for pups. We show the protocols developed are repeatable and efficient enough to be applied to a large number of animals in a relatively short period of time and may be useful for studies of other marine mammals. We caution that prediction intervals exist around mass estimates and must be accounted for when estimates are applied to biological questions. In a limited application of the method, differences in mass transfer between experienced and inexperienced maternal females and their pups were detected when prediction error variance around mass estimates was explicitly included. Similar mass‐estimation methods may therefore be useful in consideration of biological questions requiring large samples of mass previously unattainable.
DOES DIVING LIMIT BRAIN SIZE IN CETACEANS?
Authors: Marino Lori , Sol Daniel , Toren Kristen , Lefebvre Louis
Published: February 2006

Abstract

We test the longstanding hypothesis, known as the dive constraint hypothesis, that the oxygenation demands of diving pose a constraint on aquatic mammal brain size.Using a sample of 23 cetacean species we examine the relationship among six different measures of relative brain size, body size, and maximum diving duration. Unlike previous tests we include body size as a covariate and perform independent contrast analyses to control for phylogeny. We show that diving does not limit brain size in cetaceans and therefore provide no support for the dive constraint hypothesis. Instead, body size is the main predictor of maximum diving duration in cetaceans. Furthermore, our findings show that it is important to conduct robust tests of evolutionary hypotheses by employing a variety of measures of the dependent variable, in this case, relative brain size.
Bone Marrow as a Source of Endothelial Cells for Natural and Iatrogenic Vascular Repair
Authors: ISNER JEFFREY M. , KALKA CHRISTOPH , KAWAMOTO ATSUHIKO , ASAHARA TAKAYUKI
Published: February 2006

Abstract: Postnatal neovascularization has previously been considered synonymous with angiogenesis, but the finding that circulating endothelial progenitor cells (EPCs) may home to sites of neovascularization and there differentiate into endothelial cells (ECs) is consistent with “vasculogenesis,” through which the primordial vascular network is established in the embryo. Our findings suggest that growth and development of new blood vessels in the adult are not restricted to angiogenesis but encompass vasculogenesis as well, although the proportional contributions remain to be clarified. Likewise, augmented or retarded neovascularization probably involves enhancement or impariment of the vasculogenesis process.
Medicinals for the Millennia
Authors: CRAGG GORDON M. , NEWMAN DAVID J.
Published: February 2006

Abstract: Nature has been a source of medicinal agents for thousands of years, and an impressive number of modern drugs have been isolated from natural sources, many based on their use in traditional medicine. The use of herbal drugs is once more escalating in the form of complementary and alternative medicine. The past century, however, has seen an increasing role played by microorganisms in the production of the antibiotics and other drugs for the treatment of some serious diseases. With less than 1% of the microbial world currently known, advances in procedures for microbial cultivation and the extraction of nucleic acids from environmental samples from soil and marine habitats, and from symbiotic and endophytic microbes associated with terrestrial and marine macro‐organisms, will provide access to a vast untapped reservoir of genetic and metabolic diversity. By use of combinatorial chemical and biosynthetic technology, novel natural product leads will be optimized on the basis of their biological activities to yield effective chemotherapeutic and other bioactive agents.
Gene Therapy for Cardiovascular Disorders
Authors: METCALFE BEVERLY L. , SELLERS KATHLEEN W. , JENG MICHAEL JING‐REN , HUENTELMAN MATTHEW J. , KATOVICH MICHAEL J. , RAIZADA MOHAN K.
Published: February 2006

Abstract: Incidence of cardiovascular disease has reached epidemic proportions in spite of recent advances in improving the efficacy of pharmacotherapeutics. This has led many to conclude that drug therapy has reached a plateau in its effectiveness. As a result, our efforts have been diverted to explore the use of gene transfer approaches for long‐term control of these pathophysiological conditions. The purpose of this review is to present various approaches that are being undertaken to provide “proof of principle” for gene therapy for cardiovascular diseases. Finally, we will discuss the future of gene therapy and other new technologies that may further advance this field of therapeutics.
Retroviral Approaches to Gene Therapy of Cystic Fibrosis
Authors: JOHNSON LARRY G.
Published: February 2006

Abstract: Retroviral vectors are attractive as vectors for gene therapy of cystic fibrosis because of their ability to integrate into the host cell genome, which may lead to long‐term expression and, perhaps, a cure. Nevertheless, retroviral applications for gene transfer to airway epithelia have been limited by low titers and a requirement for proliferating cells. Significant advances in pseudotyping of retroviruses and in retroviral production have reduced some of the concerns regarding titer. The development of lentiviral vectors that transduce nondividing cells has also helped to establish that retroviral approaches for gene therapy of cystic fibrosis are feasible. However, the apical membrane of the airway epithelium remains a formidable barrier to gene transfer. In this review, I will discuss limitations of current retroviral gene transfer vectors and strategies to improve retroviral gene transfer efficiency to airway epithelia in vivo.
Regulated Gene Expression in Gene Therapy
Authors: ZOLTICK PHILIP W. , WILSON JAMES M.
Published: February 2006

Abstract: The original model of gene therapy, that of efficient delivery, durable transfer, and stable expression of transgenes to correct a gene defect underlying an inherited disease, is limited in light of improved understanding of the processes involved. Techniques that enable regulated expression of transgenes may enhance safety and allow us to regulate the timing and level of expression with a goal of precisely targeting a therapeutic level between the extremes of suboptimal and supraoptimal thresholds. Using regulated systems to control protein expression has practical and possibly essential roles for the success of safe and effective gene therapy in a number of clinical situations. Pharmacologically regulated gene expression is an evolving tool, and no individual system may be effective in all clinical applications.
AAV‐Mediated Gene Transfer for Hemophilia
Authors: HIGH KATHERINE A.
Published: February 2006

Abstract: Hemophilia is a particularly attractive model for developing a gene transfer approach for the treatment of disease. The protein is very well characterized, the genes are cloned and available, and there are large and small animal models of the disease. Moreover, in contrast to many diseases, there is no requirement for a specific target tissue for gene delivery, and the gene product itself does not require precise regulation of expression. Earlier efforts to establish a gene transfer approach to the treatment of hemophilia had failed to achieve the twin goals of long‐term expression at levels that were adequate to result in phenotypic improvement of the disease. We have exploited advances in vector development that occurred in the mid‐1990s to establish an experimental basis for an AAV (adeno‐associated viral vector)‐mediated gene transfer approach to the treatment of hemophilia B. Based on the observation that introduction of an AAV vector into skeletal muscle could result in sustained expression of β‐galactosidase, we engineered an AAV vector expressing human factor IX and demonstrated in immunodeficient mice that intramuscular injection of the vector resulted in long‐term expression of the secreted transgene product factor IX. Subsequently, we generated an AAV vector expressing canine factor IX; intramuscular injection into dogs with severe hemophilia B resulted in a dose‐dependent increase in circulating levels of factor IX. The animal treated at the highest dose showed prolonged expression (>3 years and still under observation) at a level (70 ng/ml, 1.4% of normal circulating levels of factor IX) likely to result in phenotypic improvement in humans. Detailed studies in tissue culture using human myotubes have shown that muscle cells are capable of executing the posttranslational modifications required for activity of factor IX, and that the specific activity of myotube‐synthesized factor IX is similar to that of hepatocyte‐synthesized material, although some details of posttranslational processing differ. Based on these and other safety and efficacy studies, a clinical trial of AAV‐mediated, muscle‐directed gene transfer for hemophilia B has been initiated. The study has a dose‐escalation design, with three subjects to be enrolled in three dose cohorts beginning with a dose of 2 × 1011 vg/kg. Results in the initial dose cohort showed no evidence of toxicity associated with vector administration or transgene expression. Analysis of muscle biopsies done on injected tissue showed clear evidence of gene transfer by PCR and Southern blot and of gene expression by immunocytochemistry. The general characteristics of muscle transduction appear similar in humans and in other animal models. The goal of dose escalation is to find a dose that is nontoxic but that results in circulating levels of factor IX >1% in all patients.
The Burden of Drug‐Resistant Tuberculosis and Mechanisms for Its Control
Authors: RAVIGLIONE MARIO C. , GUPTA RAJESH , DYE CHRISTOPHER M. , ESPINAL MARCOS A.
Published: February 2006

Abstract: Drug resistance in tuberculosis is largely a man‐made phenomenon caused by erroneous prescribing practices on the part of physicians and noncompliance on the part of patients. The global epidemiology of drug‐resistant TB, the impact of standardized short‐course chemotherapy (SSC), and the potential future evolution of MDR TB are discussed in this chapter.
Problems in Prisons Worldwide, with a Particular Focus on Russia
Authors: STERN VIVIEN
Published: February 2006

Abstract:The link between prisons and disease has existed as long as prisons have been used for punishment. The prisons of the world still have high rates of infection with hepatitis, HIV, mental illness, and tuberculosis. TB is a major cause of death in prisons, mainly as a result of overcrowding, poor physical conditions, and lack of adequate treatment. The priorities of prisoners and of public health officials are often at odds with the priorities of prison administrators and prosecutors. Prison health care should be independent of prison administration and should be answerable only to the national public health program. Efforts should be made in those countries with the highest inprisonment rates to find other solutions to maintaining order in the interests of improving public health.
The Impact of Worldwide Drug Resistance on the United Kingdom
Authors: WATSON JOHN
Published: February 2006

Abstract:The incidence of tuberculosis in the United Kingdom, which declined beginning in the middle of the 19th century, began to increase in the late 1980s. The distribution of tuberculosis by geographic area, age, and ethnic group is discussed. Drug resistance is high among U.K. residents born abroad, but the proportion of drug‐resistant cases is remaining stable.
Tuberculosis in Russia and the Problem of Multiple Drug Resistance
Authors: YEROKHIN V. V. , PUNGA V. V. , RYBKA L. N.
Published: February 2006

Abstract: Tuberculosis cases in Russia doubled from 1991 to 2000, when the incidence reached 90 per 100,000; and Russian TB mortality rates are the highest in Europe. Implementation of WHO‐recommended DOTS strategy is in the preliminary stages. The epidemiological data are presented as is the implementation strategy for stabilizing the epidemic.
The Genetics of Host Resistance and Susceptibility to Tuberculosis
Authors: DAVIES PETER , GRANGE JOHN
Published: February 2006

Abstract: The study of human genomics has the potential to aid our understanding of the interindividual and interpopulation differences in susceptibility to tuberculosis. Resistance to infection is affected by the ability of macrophages to phagocytose and destroy the bacilli. Several genes are involved in this process, and two have been the focus of recent interest: the natural resistanceassociated protein (NRAMP1) gene and the genes coding for the vitamin D receptor. Susceptibility genes have also been discovered—for example, one on the X chromosome that may explain the increased susceptibility of males to tuberculosis. Studies have also focused on the variations in virulence of the bacillus in both its drug‐susceptible and drug‐resistant forms. These mechanisms must be understood in order to prevent, or combat, the emergence of a virulent, multidrug‐resistant form of the bacillus that would be uncontrollable by means of today's treatment strategies.
The Clinical Management of the Drug‐Resistant Patient
Authors: ORMEROD PETER
Published: February 2006

Abstract: The specific management of drug‐resistant patients is only possible where facilities exist for both mycobacterial culture and for drug‐susceptibility testing. Treatment guidelines in the United Kingdom and elsewhere are predicated on the drug‐resistance data prevailing in the circumstances of their use. In developed countries, the inclusion of the fourth drug (ethambutol but occasionally streptomycin) depends on the level of isoniazid resistance expected or known in a given patient group. Most parts of the world do not have the capabilities to perform mycobacterial culture and drug‐susceptibility testing. In these countries, therefore, the “standard” advised regimen has to cover the possibility of the commoner drug resistances. The view taken in the United Kingdom is that where drug‐susceptibility tests are available, they should be followed, and treatment modified. The drug treatment of multidrug‐resistant tuberculosis (MDR TB), defined as combined resistance to rifampicin and isoniazid, plus or minus other antituberculosis drugs, is complex, time consuming, and demanding on both patient and physician. In the United Kingdom the advice is that treatment should only be carried out by physicians with substantial experience in managing complex resistant cases, only in hospitals with appropriate isolation facilities, and in very close liaison with Mycobacteriology Reference Centres. Treatment should start with five or more drugs to which the organism is, or is likely to be, susceptible and continued until sputum cultures become negative. Treatment with three drugs should continue for at least an additional nine months.
Multidrug‐Resistant Tuberculosis and HIV Infection
Authors: POZNIAK ANTON
Published: February 2006

Abstract: In the 1990s, outbreaks of multidrug‐resistant tuberculosis (MDR TB) among HIV‐positive patients ultimately led to the establishment in the developed world of a comprehensive TB control strategy for these patients that is effective. The treatment regimen for HIV and MDR TB is complicated by the fact that most of the drugs used have not been studied for interactions with antivirals. Hence, overlapping toxicities require intensive management and monitoring of these patients. Good public health policy is essential to preventing MDR TB outbreaks among immunosuppressed patients.
Moral Problems in the Use of Coercion in Dealing with Nonadherence in the Diagnosis and Treatment of Tuberculosis
Authors: DOYAL LEN
Published: February 2006

Abstract: Coercion and detainment can be a morally acceptable strategy to fight the spread of tuberculosis, but these measures need to be placed into a much broader context than that of their short‐term potential effectiveness. TB should be de‐stigmatized by full acknowledgment that we all share the blame for its perpetuation. When coercion and detention are necessary, they should incorporate a strategy of optimum protection for minimum violation of autonomy. National and international health care programs should provide effective and nonthreatening treatments for TB and other related illnesses such as HIV and should develop policies to tackle the environmental causes of TB and provide support for vulnerable victims. Corporate pressures to continue world poverty must be undermined.
Multidrug‐Resistant Tuberculosis
Authors: Moore‐Gillon John
Published: February 2006

Abstract: The costs of multidrug‐resistant tuberculosis (MDR TB) reach far beyond the cost of the clinical treatment of the patient. The first impact of the discovery of MDR TB in a population is the need to recognize that all TB patients have the potential of being MDR. Public health measures to prevent the spread of MDR TB, or to control or reverse the problem where spread has already occurred, can be extremely expensive to implement. At the level of the individual patient, the second‐line drugs used to treat MDR TB are more expensive, and the remaining first‐line drugs will have to be used for a longer time than in drug‐susceptible TB. Negative‐pressure units add to the costs of treatment, as does the increased nursing intensity required. The cost to the wider economy includes lost productivity and lost tax revenue to the state as well as the cost of supporting the family if the patient is the breadwinner.
Defibrillation of the heart: insights into mechanisms from modelling studies
Authors: Trayanova Natalia
Published: February 2006

Despite its critical role in restoring cardiac rhythm and thus in saving human life, cardiac defibrillation remains poorly understood. Further mechanistic inquiry is hampered by the inability of presently available experimental techniques to resolve, with sufficient accuracy, electrical behaviour confined to the depth of the ventricles. The objective of this review article is to demonstrate that realistic 3‐D simulations of the ventricular defibrillation process in close conjunction with experimental observations are capable of bringing a new level of understanding of the electrical events that ensue from the interaction between fibrillating myocardium and applied shock. The article does this by reviewing the results of two studies, one on vulnerability to electric shocks and another on defibrillation. An overview of the modelling tools used in these studies is also provided.
Nitric oxide synthase inhibition reduces O2 cost of force development and spares high‐energy phosphates following contractions in pump‐perfused rat hindlimb muscles
Authors: Baker David J. , Krause Daniel J. , Howlett Richard A. , Hepple Russell T.
Published: February 2006

The purpose of the present experiments was to test the hypotheses that: (i) nitric oxide synthase (NOS) inhibition reduces the O2 cost of force development across a range of contractile demands; and (ii) this reduced O2 cost of force development would be reflected in a sparing of intramuscular higher energy phosphates. Rat distal hindlimb muscles were pump perfused in situ and electrically stimulated (200 ms trains with pulses at 100 Hz, each pulse 0.05 ms duration) for 1 min each at 15, 30 and 60 tetani min−1 and for 2 min at 90 tetani min−1 in three groups: 0.01 mm adenosine; 1 mm d‐NAME and 0.01 mm adenosine (d‐NAME); and 1 mm l‐NAME and 0.01 mm adenosine (l‐NAME). The gastrocnemius–plantaris–soleus muscle group was freeze clamped post‐contractions for metabolite analyses. Force was 19% higher and oxygen uptake
was 20% lower with l‐NAME versus adenosine, and there was a 35% reduction in
/time‐integrated tension versus adenosine and 24% versusd‐NAME that was independent of contraction frequency. l‐NAME treatment produced a 33% sparing of muscle phosphocreatine (PCr), and intramuscular lactate was no different between groups. In contrast, d‐NAME reduced force by 30%,
by 29% and the O2 cost of force development by 15% compared with adenosine, but had no effect on the degree of intramuscular ATP and PCr depletion. These results show that NOS inhibition improved the metabolic efficiency of force development, either by improving the ATP yield for a given O2 consumption or by reducing the ATP cost of force development. In addition, these effects were independent of contraction frequency.
Myotendinous plasticity to ageing and resistance exercise in humans
Authors: Reeves N. D. , Narici M. V. , Maganaris C. N.
Published: February 2006

The age‐related loss of muscle mass known as senile sarcopenia is one of the main determinants of frailty in old age. Molecular, cellular, nutritional and hormonal mechanisms are at the basis of sarcopenia and are responsible for a progressive deterioration in skeletal muscle size and function. Both at single‐fibre and at whole‐muscle level, the loss of force exceeds that predicted by the decrease in muscle size. For single fibres, the loss of intrinsic force is mostly due to a loss in myofibrillar protein content. For whole muscle, in addition to changes in neural drive, alterations in muscle architecture and in tendon mechanical properties, exemplified by a reduction in tendon stiffness, have recently been shown to contribute to this phenomenon. Resistance training can, however, cause substantial gains in muscle mass and strength and provides a protective effect against several of the cellular and molecular changes associated with muscle wasting and weakness. In old age, not only muscles but also tendons are highly responsive to training, since an increase in tendon stiffness has been observed after a period of increased loading. Many of the myotendinous factors characterizing ageing can be at least partly reversed by resistance training.
Mechanisms of CO2/H+ chemoreception by respiratory rhythm generator neurons in the medulla from newborn rats in vitro
Authors: Kawai Akira , Onimaru Hiroshi , Homma Ikuo
Published: February 2006

We investigated mechanisms of CO2/H+ chemoreception in the respiratory centre of the medulla by measuring membrane potentials of pre‐inspiratory neurons, which are putative respiratory rhythm generators, in the brainstem–spinal cord preparation of the neonatal rat. Neuronal response was tested by changing superfusate CO2 concentration from 2% to 8% at constant HCO3− concentration (26 mm) or by changing pH from 7.8 to 7.2 by reducing HCO3− concentration at constant CO2 (5%). Both respiratory and metabolic acidosis lead to depolarization of neurons with increased excitatory synaptic input and increased burst rate. Respiratory acidosis potentiated the amplitude of the neuronal drive potential. In the presence of tetrodotoxin (TTX), membrane depolarization persisted during respiratory and metabolic acidosis. However, the depolarization was smaller than that before application of TTX, which suggests that some neurons are intrinsically, and others synaptically, chemosensitive to CO2/H+. Application of Ba2+ blocked membrane depolarization by respiratory acidosis, whereas significant depolarization in response to metabolic acidosis still remained after application of Cd2+ and Ba2+. We concluded that the intrinsic responses to CO2/H+changes were mediated by potassium channels during respiratory acidosis, and that some other mechanisms operate during metabolic acidosis. In low‐Ca2+, high‐Mg2+ solution, an increased CO2 concentration induced a membrane depolarization with a simultaneous increase of the burst rate. Pre‐inspiratory neurons could adapt their baseline membrane potential to external CO2/H+ changes by integration of these mechanisms to modulate their burst rates. Thus, pre‐inspiratory neurons might play an important role in modulation of respiratory rhythm by central chemoreception in the brainstem–spinal cord preparation.
Activity‐dependent regulation of synaptic strength and neuronal excitability in central auditory pathways
Authors: Walmsley Bruce , Berntson Amy , Leao Richardson N. , Fyffe Robert E. W.
Published: February 2006

Neural activity plays an important role in regulating synaptic strength and neuronal membrane properties. Attempts to establish guiding rules for activity‐dependent neuronal changes have led to such concepts as homeostasis of cellular activity and Hebbian reinforcement of synaptic strength. However, it is clear that there are diverse effects resulting from activity changes, and that these changes depend on the experimental preparation, and the developmental stage of the neural circuits under study. In addition, most experimental evidence on activity‐dependent regulation comes from reduced preparations such as neuronal cultures. This review highlights recent results from studies of the intact mammalian auditory system, where changes in activity have been shown to produce alterations in synaptic and membrane properties at the level of individual neurons, and changes in network properties, including the formation of tonotopic maps.
Fast IPSCs in rat thalamic reticular nucleus require the GABAA receptor β1 subunit
Authors: Huntsman Molly M. , Huguenard John R.
Published: February 2006

Synchrony within the thalamocortical system is regulated in part by intranuclear synaptic inhibition within the reticular nucleus (RTN). Inhibitory postsynaptic currents (IPSCs) in RTN neurons are largely characterized by slow decay kinetics that result in powerful and prolonged suppression of spikes. Here we show that some individual RTN neurons are characterized by highly variable mixtures of fast, slow and mixed IPSCs. Heterogeneity arose largely through differences in the contribution of an initial decay component (τD∼10 ms) which was insensitive to loreclezole, suggesting involvement of the GABAA receptor β1 subunit. Single‐cell RT‐PCR revealed the presence of β1 subunit mRNA only in those neurons whose IPSCs were dominated by a rapid and prominent initial decay phase. These data show that brief, β1‐dependent, loreclezole‐insensitive IPSCs are present in a subpopulation of RTN neurons, and suggest that striking differences in IPSC heterogeneity within single neurons can result from of the presence or absence of a single GABAA receptor subunit.
Reactive and Nonreactive Scattering of H
2
from a Metal Surface Is Electronically Adiabatic
Authors: Nieto Pablo , Pijper Ernst , Barredo Daniel , Laurent Guillaume , Olsen Roar A. , Baerends Evert-Jan , Kroes Geert-Jan , Farías Daniel
Published: February 2006

The Born-Oppenheimer approximation of uncoupled electronic and nuclear motion is a standard tool of the computational chemist. However, its validity for molecule–metal surface reactions, which are important to heterogeneous catalysis, has been questioned because of the possibility of electron-hole pair excitations. We have performed experiments and calculations on the scattering of molecular hydrogen from a catalytically relevant metal surface, obtaining absolute probabilities for changes in the molecule's velocity parallel to the representative Pt(111) surface. The comparison for in-plane and out-of-plane scattering and results for dissociative chemisorption in the same system show that for hydrogen-metal systems, reaction and diffractive scattering can be accurately described using the Born-Oppenheimer approximation.
Structure of the Hydrophilic Domain of Respiratory Complex I from
Thermus thermophilus
Authors: Sazanov Leonid A. , Hinchliffe Philip
Published: February 2006

Respiratory complex I plays a central role in cellular energy production in bacteria and mitochondria. Its dysfunction is implicated in many human neurodegenerative diseases, as well as in aging. The crystal structure of the hydrophilic domain (peripheral arm) of complex I from
Thermus thermophilus
has been solved at 3.3 angstrom resolution. This subcomplex consists of eight subunits and contains all the redox centers of the enzyme, including nine iron-sulfur clusters. The primary electron acceptor, flavin-mononucleotide, is within electron transfer distance of cluster N3, leading to the main redox pathway, and of the distal cluster N1a, a possible antioxidant. The structure reveals new aspects of the mechanism and evolution of the enzyme. The terminal cluster N2 is coordinated, uniquely, by two consecutive cysteines. The novel subunit Nqo15 has a similar fold to the mitochondrial iron chaperone frataxin, and it may be involved in iron-sulfur cluster regeneration in the complex.
Development of fetal haemoglobin-blood cells (F cells) within colorectal tumour tissues
Authors: Wolk M , Martin J E , Reinus C
Published: February 2006

Aim:To evaluate the sources of fetal haemoglobin (HbF) as an indicator in cancer. An immunohistochemical study was carried out on some of the most common kinds of cancer. All of these cancers had serologically high levels of HbF as evaluated previously.

Methods:Immunoaffinity-purified anti-HbF was immunohistochemically used to study F cell distribution in the following cancers: colorectal adenocarcinoma, urinary bladder transitional cell carcinoma, brain tumours, lung carcinoma, breast adenocarcinoma, leukaemia, Burkitt’s lymphoma and endometrial carcinoma.

Results:In colorectal adenocarcinoma, HbF-containing red blood cells (FRBC) were present within thin-walled vessels or were disposed in dense clusters within the tumour. Some of these cells were nucleated or binucleated HbF-erythroblasts or HbF-normoblasts (FNBS). In two cases, high levels of mitoses within HbF-erythroblasts were observed. In half of the cases with transitional cell carcinoma of the urinary bladder, regional intratumoral blood vessels were found to contain 5–50% FRBC. In the other tumours examined, F cells were not observed. FRBCs, however, were occasionally observed in the regional lymph nodes of some of these cancers.

Conclusions:The evaluation of HbF as a potential plasma marker is suggested by the high concentration of FRBCs in colorectal tumours. The apparent development of FRBCs in colorectal tumour tissues is an interesting observation, as these cells were previously thought to develop in medullary or lymphoid tissues. It is thus suggested that the colonic microenvironment may stimulate extramedullary fetal-type haematopoiesis.
Primary prevention of latex related sensitisation and occupational asthma: a systematic review
Authors: LaMontagne A D , Radi S , Elder D S , Abramson M J , Sim M
Published: February 2006

Methods:Eight primary prevention intervention studies on natural rubber latex (NRL) published since 1990 were identified and reviewed. This is the largest evidence base of primary prevention studies for any occupational asthmagen.

Results:Review of this small and largely observational evidence base supports the following evidence statement: Substitution of powdered latex gloves with low protein powder-free NRL gloves or latex-free gloves greatly reduces NRL aeroallergens, NRL sensitisation, and NRL-asthma in healthcare workers. Evidence in support of this statement is ranked SIGN level 2+, referring to well conducted case-control or cohort studies with a low risk of confounding, bias, or chance and a moderate probability that the relationship is causal.

Conclusion:Substitution of powdered latex gloves with low protein powder-free NRL gloves or latex-free gloves promises benefits to both workers’ health and cost and human resource savings for employers. This message should be broadly disseminated beyond the hospital sector to include other healthcare settings (such as aged care facilities) as well as food service and other industries where latex gloves might be used.
A PSEUDO-UNITARY ENSEMBLE OF RANDOM MATRICES, PT-SYMMETRY AND THE RIEMANN HYPOTHESIS
Authors: AHMED ZAFAR , JAIN SUDHIR R.
Published: February 2006

An ensemble of 2×2 pseudo-Hermitian random matrices is constructed that possesses real eigenvalues with level-spacing distribution exactly as for the Gaussian unitary ensemble found by Wigner. By a re-interpretation of Connes' spectral interpretation of the zeros of Riemann zeta function, we propose to enlarge the scope of search of the Hamiltonian connected with the celebrated Riemann hypothesis by suggesting that the Hamiltonian could also be PT-symmetric (or pseudo-Hermitian).
ARGUMENTS FOR F-THEORY
Authors: BOYA LUIS J.
Published: February 2006

After a brief review of string and M-theory we point out some deficiencies. Partly to rectify them, we present several arguments for "F-theory", enlarging spacetime to (2, 10) signature, following the original suggestion of C. Vafa. We introduce a suggestive supersymmetric 27-plet of particles, associated to the exceptional symmetric hermitian space E6/ Spin c(10). Several possible future directions, including using projective rather than metric geometry, are mentioned. We should emphasize that F-theory is yet just a very provisional attempt, lacking clear dynamical principles.
A COMMENTARY ON COSMOLOGICAL ENTROPY BOUNDS
Authors: MEDVED A. J. M.
Published: February 2006

There has been, quite recently, a discussion on how holographic-inspired bounds might be used to encompass the present-day dark energy and early-universe inflation into a single paradigm. In the current treatment, we point out an inconsistency in the proposed framework and then provide a viable resolution. We also elaborate on some of the implications of this framework and further motivate the proposed holographic connection. The manuscript ends with a more speculative note on cosmic time as an emergent (holographically induced) construct.
MEASUREMENT OF THE CKM ANGLE α WITH THE B-FACTORIES
Authors: BEVAN ADRIAN
Published: February 2006

B-meson decays involving b→u transitions are sensitive to the unitarity triangle angle α (or ϕ2). The B-factories at SLAC and KEK have made significant progress toward the measurement of α in recent years. This paper summarizes the results of the B-factories' constraints on α.
A NEW FERROELECTRIC PbZr0.52Ti0.48O3 POLYMORPH OF NANOPARTICLES
Authors: RAM S. , MISHRA A.
Published: February 2006

Lead-zirconate-titanate PbZr 1-x Ti x O 3 has superb ferroelectric properties in x~0.48 morphotropic phase boundary phase. In bulk form it has a P4mm tetragonal crystal structure of lattice parameters a=0.4036 nm and c=0.4146 nm at room temperature or above, and a Cm monoclinic structure of a=0.5722 nm , b=0.5710 nm , c=0.4137 nm and β=90.50° at lower temperatures. A new polymorph lies in an orthorhombic structure of a=0.4038 nm , b=0.4017 nm , and c=0.4148 nm in small particles of size such as 20 nm. It has an enhanced value of density of 8.033 g/cm3 relative to 8.006 g/cm3 in the tetragonal or 8.000 g/cm3 in the monoclinic bulk structure in a rather incompressible and hard material. The result is analyzed with X-ray diffraction of the sample of nanoparticles.
ANALYSIS OF ATOM FOCUSING IN A STANDING WAVE LASER FIELD FOR NANOMETER-SCALE FABRICATION
Authors: CHEN XIANZHONG , SHI JIANPING , LUO XIANGANG , ZHANG CHUNMEI , CHEN XUNAN , XING TINGWEN , DU CHUNLEI , YAO HANMIN
Published: February 2006

We present a calculation model to investigate the focusing characteristics of an atomic beam in a laser standing wave, taking the wave nature of the atomic propagation into account. The effects of atom source, optical parameters of the laser field and the substrate position on atom focusing are analyzed. Numerical simulations indicate that the best focusing performance can be obtained by repositioning the substrate or optimizing the longitudinal atomic beam speed, laser intensity and the detuning of the laser beam. The feature width of the nanostructure is mainly determined by the transverse speed distribution of atoms. Some methods for optimizing experimental parameters are suggested.
SEMANTIC INTEROPERABILITY AND INFORMATION FLUIDITY
Authors: JIANG GUOFEI , CYBENKO GEORGE , HENDLER JAMES A.
Published: February 2006

Ontologies are developed to describe data semantics on the Semantic Web. Given the distributed nature and scale of the Semantic Web, a large number of ontologies with different terminologies and structures will be created to describe the same concepts and domains. Without semantic mapping, information fluidity within the Web could be blocked at the boundaries of these ontologies. Therefore, ontology mapping is needed to translate datasets represented by disparate ontologies. We believe that over time communities will incrementally build an ontology mapping between select ontologies based on their own communication interests. How will these interest-driven mapping activities eventually change semantic interoperability and information fluidity across the Web? This paper proposes metrics to quantify information fluidity and builds an analytical model with "small-world" graph theory to analyze the growth of the Semantic Web. Further with this model, we analyze how information fluidity can evolve by "market-driven" semantic mapping activities occurring across the Web. Our results can be useful in evaluating mapping efforts needed for large-scale heterogeneous information systems. One conclusion, based on this model, is that the development of decentralized ontology mappings can lead to significant information fluidity within the Semantic Web.
POSEIDON: A FRAMEWORK TO ASSIST WEB PROCESS DESIGN BASED ON BUSINESS CASES
Authors: CARDOSO JORGE
Published: February 2006

Systems and infrastructures are currently being developed to support Web services and Web processes. One prominent solution to manage and coordinate Web services is the use of workflow technology. For more than two decades now, workflow management systems architectures, language specifications, and workflow analysis techniques have been extensively studied. While these areas of research have made the development of sophisticated workflow systems possible, one important research area that has been overlooked is the lifecycle of process application development. As a result, current process management systems support the analysis, enactment, and ad hoc design of workflows, but they lack the tools and methods to assist process design. The purpose of our study is to present a framework to assist and guide process analysts and designers in their task. The Poseidon framework includes a participative and an analytical design method. The participative phase uses a clean sheet approach and starts by constructing a business case table which captures all the business cases represented by a process. Afterward, an analytical design phase is followed where scheduling functions are derived from the business case table and are used to build the structure of a process.
APPLYING ORCHESTRATION AND CHOREOGRAPHY OF WEB SERVICES ON DYNAMIC VIRTUAL MARKETPLACES
Authors: SANTOS IVO JOSÉ GARCIA DOS , MADEIRA EDMUNDO ROBERTO MAURO
Published: February 2006

The Service-Oriented Architecture promises to be an affordable solution for the integration of heterogeneous systems through the Internet. In the e-Business field, this promise represents a great chance for companies to increase competitiveness and to enable the enactment of new collaborative e-Business processes. In this paper, we present a Virtual Marketplace infrastructure, the VM-Flow, which uses Dynamic Composition of Web Services (Orchestration and Choreography) as a fundamental technique to enable interorganizational business interactions in the context of Dynamic Virtual Enterprises. The VM-Flow platform is workflow-based and also introduces a series of interaction policies to deal with aspects like autonomy and privacy. A platform model is presented together with details on the infrastructure prototype and on an application built over it.
AGENT-ENHANCED COLLABORATIVE ACTIVITY IN ORGANIZED SETTINGS
Authors: PARTSAKOULAKIS IOANNIS , VOUROS GEORGE
Published: February 2006

For groups of agents to act collaboratively, they need to recognize the need for collaboration, decide on the method to be followed for achieving goal states, assign responsibilities to subgroups and individuals, and so on, until responsibilities that can be fulfilled by individuals are reached. Aiming to support collaborative activity of humans within organized settings, this paper introduces a set of constructs for specifying organizational structures and introduces an explicit representation of individual and collaborative responsibilities within organizations. We conjecture that group members create common awareness towards recognizing the need for collaboration by forming group acceptances. Acceptances are formed by means of shared practices and beliefs of individual agents. The paper introduces state recognition recipes that drive group members within organizations to form acceptances, and thoroughly explains the exploitation of these recipes in conjunction to state achievement recipes for achieving goal states and fulfilling responsibilities collaboratively.
THE OPINION GAME: STOCK PRICE EVOLUTION FROM MICROSCOPIC MARKET MODELING
Authors: BOVIER ANTON , ČERNÝ JIŘÍ , HRYNIV OSTAP
Published: February 2006

We propose a class of Markovian agent based models for the time evolution of a share price in an interactive market. The models rely on a microscopic description of a market of buyers and sellers who change their opinion about the stock value in a stochastic way. The actual price is determined in realistic way by matching (clearing) offers until no further transactions can be performed. Some analytic results for simple special cases are presented. We also propose basic interaction mechanisms and show in simulations that these already reproduce certain particular features of prices in real stock markets.