bluuebunny/crossref_metadata_2025 huggingface dataset:
Arctic Seabirds Transport Marine-Derived Contaminants
Authors: Blais Jules M. , Kimpe Lynda E. , McMahon Dominique , Keatley Bronwyn E. , Mallory Mark L. , Douglas Marianne S. V. , Smol John P.
Published: July 2005

Long-range atmospheric transport of pollutants is generally assumed to be the main vector for arctic contamination, because local pollution sources are rare. We show that arctic seabirds, which occupy high trophic levels in marine food webs, are the dominant vectors for the transport of marine-derived contaminants to coastal ponds. The sediments of ponds most affected by seabirds had 60 times higher DDT, 25 times higher mercury, and 10 times higher hexachlorobenzene concentrations than nearby control sites. Bird guano greatly stimulates biological productivity in these extreme environments but also serves as a major source of industrial and agricultural pollutants in these remote ecosystems.
Controlled Single-Photon Emission from a Single Trapped Two-Level Atom
Authors: Darquié B. , Jones M. P. A. , Dingjan J. , Beugnon J. , Bergamini S. , Sortais Y. , Messin G. , Browaeys A. , Grangier P.
Published: July 2005

By illuminating an individual rubidium atom stored in a tight optical tweezer with short resonant light pulses, we created an efficient triggered source of single photons with a well-defined polarization. The measured intensity correlation of the emitted light pulses exhibits almost perfect antibunching. Such a source of high-rate, fully controlled single-photon pulses has many potential applications for quantum information processing.
Science as Comic Metaphysics
Authors: Lindee Susan
Published: July 2005

The Worlds of Herman Kahn
. The Intuitive Science of Thermonuclear War.
By Sharon Ghamari-Tabrizi
. Harvard University Press, Cambridge, MA, 2005. 395 pp. $26.95, £17.95, €24.90. ISBN 0-674-01714-5.

In the course of exploring the many facets of the life of the influential nuclear strategist, the author also addresses how we deal with "the unknown unknowns of national security."
Apolipoprotein L-I Promotes Trypanosome Lysis by Forming Pores in Lysosomal Membranes
Authors: Pérez-Morga David , Vanhollebeke Benoit , Paturiaux-Hanocq Françoise , Nolan Derek P. , Lins Laurence , Homblé Fabrice , Vanhamme Luc , Tebabi Patricia , Pays Annette , Poelvoorde Philippe , Jacquet Alain , Brasseur Robert , Pays Etienne
Published: July 2005

Apolipoprotein L-I is the trypanolytic factor of human serum. Here we show that this protein contains a membrane pore-forming domain functionally similar to that of bacterial colicins, flanked by a membrane-addressing domain. In lipid bilayer membranes, apolipoprotein L-I formed anion channels. In
Trypanosoma brucei
, apolipoprotein L-I was targeted to the lysosomal membrane and triggered depolarization of this membrane, continuous influx of chloride, and subsequent osmotic swelling of the lysosome until the trypanosome lysed.
Zoonotic Potential of the Microsporidia
Authors: Mathis Alexander , Weber Rainer , Deplazes Peter
Published: July 2005

Microsporidia are long-known parasitic organisms of almost every animal group, including invertebrates and vertebrates. Microsporidia emerged as important opportunistic pathogens in humans when AIDS became pandemic and, more recently, have also increasingly been detected in otherwise immunocompromised patients, including organ transplant recipients, and in immunocompetent persons with corneal infection or diarrhea. Two species causing rare infections in humans,
Encephalitozoon cuniculi
and
Brachiola vesicularum
, had previously been described from animal hosts (vertebrates and insects, respectively). However, several new microsporidial species, including
Enterocytozoon bieneusi
, the most prevalent human microsporidian causing human immunodeficiency virus-associated diarrhea, have been discovered in humans, raising the question of their natural origin. Vertebrate hosts are now identified for all four major microsporidial species infecting humans (
E. bieneusi
and the three
Encephalitozoon
spp.), implying a zoonotic nature of these parasites. Molecular studies have identified phenotypic and/or genetic variability within these species, indicating that they are not uniform, and have allowed the question of their zoonotic potential to be addressed. The focus of this review is the zoonotic potential of the various microsporidia and a brief update on other microsporidia which have no known host or an invertebrate host and which cause rare infections in humans.
Diagnosis of Lyme Borreliosis
Authors: Aguero-Rosenfeld Maria E. , Wang Guiqing , Schwartz Ira , Wormser Gary P.
Published: July 2005

A large amount of knowledge has been acquired since the original descriptions of Lyme borreliosis (LB) and of its causative agent,Borrelia burgdorferisensu stricto. The complexity of the organism and the variations in the clinical manifestations of LB caused by the differentB. burgdorferisensu lato species were not then anticipated. Considerable improvement has been achieved in detection ofB. burgdorferisensu lato by culture, particularly of blood specimens during early stages of disease. Culturing plasma and increasing the volume of material cultured have accomplished this. Further improvements might be obtained if molecular methods are used for detection of growth in culture and if culture methods are automated. Unfortunately, culture is insensitive in extracutaneous manifestations of LB. PCR and culture have high sensitivity on skin samples of patients with EM whose diagnosis is based mostly on clinical recognition of the lesion. PCR on material obtained from extracutaneous sites is in general of low sensitivity, with the exception of synovial fluid. PCR on synovial fluid has shown a sensitivity of up to >90% (when using four different primer sets) in patients with untreated or partially treated Lyme arthritis, making it a helpful confirmatory test in these patients. Currently, the best use of PCR is for confirmation of the clinical diagnosis of suspected Lyme arthritis in patients who are IgG immunoblot positive. PCR should not be used as the sole laboratory modality to support a clinical diagnosis of extracutaneous LB. PCR positivity in seronegative patients suspected of having late manifestations of LB most likely represents a false-positive result. Because of difficulties in direct methods of detection, laboratory tests currently in use are mainly those detecting antibodies toB. burgdorferisensu lato. Tests used to detect antibodies toB. burgdorferisensu lato have evolved from the initial formats as more knowledge on the immunodominant antigens has been collected. The recommendation for two-tier testing was an attempt to standardize testing and improve specificity in the United States. First-tier assays using whole-cell sonicates ofB. burgdorferisensu lato need to be standardized in terms of antigen composition and detection threshold of specific immunoglobulin classes. The search for improved serologic tests has stimulated the development of recombinant protein antigens and the synthesis of specific peptides from immunodominant antigens. The use of these materials alone or in combination as the source of antigen in a single-tier immunoassay may someday replace the currently recommended two-tier testing strategy. Evaluation of these assays is currently being done, and there is evidence that certain of these antigens may be broadly cross-reactive with theB. burgdorferisensu lato species causing LB in Europe.
Recognition ofStaphylococcus aureusby the Innate Immune System
Authors: Fournier Bénédicte , Philpott Dana J.
Published: July 2005

The gram-positive bacteriumStaphylococcus aureusis a major pathogen responsible for a variety of diseases ranging from minor skin infections to life-threatening conditions such as sepsis. Cell wall-associated and secreted proteins (e.g., protein A, hemolysins, and phenol-soluble modulin) and cell wall components (e.g., peptidoglycan and alanylated lipoteichoic acid) have been shown to be inflammatory, and these staphylococcal components may contribute to sepsis. On the host side, many host factors have been implicated in the innate detection of staphylococcal components. One class of pattern recognition molecules, Toll-like receptor 2, has been shown to function as the transmembrane component involved in the detection of staphylococcal lipoteichoic acid and phenol-soluble modulin and is involved in the synthesis of inflammatory cytokines by monocytes/macrophages in response to these components. Nod2 (nucleotide-binding oligomerization domain 2) is the intracellular sensor for muramyl dipeptide, the minimal bioactive structure of peptidoglycan, and it may contribute to the innate immune defense againstS. aureus. The staphylococcal virulence factor protein A was recently shown to interact directly with tumor necrosis factor receptor 1 in airway epithelium and to reproduce the effects of tumor necrosis factor alpha. Finally, peptidoglycan recognition protein L is an amidase that inactivates the proinflammatory activities of peptidoglycan. However, peptidoglycan recognition protein L probably plays a minor role in the innate immune response toS. aureus. Thus, several innate immunity receptors may be implicated in host defense againstS. aureus.
Plasmodium ovale
: Parasite and Disease
Authors: Collins William E. , Jeffery Geoffrey M.
Published: July 2005

Humans are infected by four recognized species of malaria parasites. The last of these to be recognized and described is
Plasmodium ovale
. Like the other malaria parasites of primates, this parasite is only transmitted via the bites of infected
Anopheles
mosquitoes. The prepatent period in the human ranges from 12 to 20 days. Some forms in the liver have delayed development, and relapse may occur after periods of up to 4 years after infection. The developmental cycle in the blood lasts approximately 49 h. An examination of records from induced infections indicated that there were an average of 10.3 fever episodes of ≥101°F and 4.5 fever episodes of ≥104°F. Mean maximum parasite levels were 6,944/μl for sporozoite-induced infections and 7,310/μl for trophozoite-induced infections. Exoerythrocytic stages have been demonstrated in the liver of humans, chimpanzees, and
Saimiri
monkeys following injection of sporozoites. Many different
Anopheles
species have been shown to be susceptible to infection with
P. ovale
, including
A. gambiae
,
A. atroparvus
,
A. dirus
,
A. freeborni
,
A. albimanus
,
A. quadrimaculatus
,
A. stephensi
,
A. maculatus
,
A. subpictus
, and
A. farauti
. An enzyme-linked immunosorbent assay has been developed to detect mosquitoes infected with
P. ovale
using a monoclonal antibody directed against the circumsporozoite protein.
Plasmodium ovale
is primarily distributed throughout sub-Saharan Africa. It has also been reported from numerous islands in the western Pacific. In more recent years, there have been reports of its distribution on the Asian mainland. Whether or not it will become a major public health problem there remains to be seen. The diagnosis of
P. ovale
is based primarily on the characteristics of the blood stages and its differentiation from
P. vivax
. The sometimes elliptical shape of the infected erythrocyte is often diagnostic when combined with other, subtler differences in morphology. The advent of molecular techniques, primarily PCR, has made diagnostic confirmation possible. The development of techniques for the long-term frozen preservation of malaria parasites has allowed the development diagnostic reference standards for
P. ovale
. Infections in chimpanzees are used to provide reference and diagnostic material for serologic and molecular studies because this parasite has not been shown to develop in other nonhuman primates, nor has it adapted to in vitro culture. There is no evidence to suggest that
P. ovale
is closely related phylogenetically to any other of the primate malaria parasites that have been examined.
Theoretical Study of Bipolaron Dynamics in Polyparaphenylene: II. Density Functional Theory (DFT) Calculations on Neutral Dimers and Semiempirical Hückel-Type Calculations on Neutral and Charged Model Chains
Authors: Förner Wolfgang
Published: July 2005

We have derived earlier the rather lengthy formalism for time simulations in poly(p-phenylene), treating the rings as semirigid rotors. To this end the Euler-Lagrange formalism had to be used. As a first step we intended to parametrize the simplified Hückel-type hamiltonian on the basis of density functional theory (DFT) calculations on some dimeric model systems. The results of this attempt are reported here. However, calculations on much longer chains, containing up to 200 rings, show a clear tendency of our model to favor the quinoid B-phase structure over the aromatic one. Further, in doubly charged chains, the charge tends to remain unseparated and to be completely delocalized over virtually the complete part of the chain, that is in B-phase conformation. The bipolaron width turns out to be extremely small, of about 10 rings in a chain having 200 rings. This is rather unexpected and interpreted as a shortcoming of the Hückel-type nature of the hamiltonian. The reason is that in the Hückel-type model the two electrons, taken away to charge the chain, are from the same orbital, and thus charge separation is more difficult, leading, in this case, only to a delocalization, keeping the bipolaron small. We assume, that in line with Prof. Paldus' work, the inclusion of direct electron-electron interactions in the form of a Pariser-Parr-Pople (PPP) type model could overcome this difficulty. The treatment has to be done, probably, in an open shell form to make possible spin separation, if necessary. Care has to be taken for spin contaminations in such treatments and possibly even the explicit inclusion of electron correlation might be necessary. In this paper we report our model which was derived in detail in a previous paper. Then we discuss the parametrization attempts and our results on longer chains. In conclusion our suggestion is that a PPP type model must be used at least to allow for bipolaron calculations and confinement of the two like charges. Such calculations would be the content of a forthcoming paper.
The Fock-Space Coupled-Cluster Method in the Calculation of Excited State Properties
Authors: Musiał Monika , Meissner Leszek
Published: July 2005

Our recently developed intermediate Hamiltonian Fock-space coupled-cluster (FS-CC) method with singles and doubles is applied to calculation of equilibrium geometries, harmonic frequencies and adiabatic excitation energies for some excited states of N2 and CO. Due to the intermediate Hamiltonian formulation, which provides a robust computational scheme for solving the FS-CC equations, and the efficient factorization strategy, relatively large basis sets and reference spaces are employed permitting a comparison of calculated properties with experimental data.
Frozen Natural Orbitals: Systematic Basis Set Truncation for Coupled-Cluster Theory
Authors: Taube Andrew G. , Bartlett Rodney J.
Published: July 2005

The method of frozen natural orbital (FNO) basis set truncation for coupled-cluster theory is described. Numerical comparisons of the FNO potential energy surfaces of a group of small molecules at the CCSD(T) level in DZP, cc-pVTZ, cc-pVQZ bases show that truncation of up to 50% of the virtual space yields CC correlation energies that are accurate to 90 or 95% when added to the full MBPT(2) basis result. The FNO truncation method is also applied to dimethylnitramine (DMNA): both the equilibrium structure and dimer interactions, yielding results at the CCSD(T) level in both a DZP and cc-pVTZ basis set that agree with literature values. CCSD(T) calculations at two possible equilibrium structures of 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX) in a truncated DZP basis are also reported.
Covariation in the socioeconomic determinants of self rated health and happiness: a multivariate multilevel analysis of individuals and communities in the USA
Authors: Subramanian S V , Kim Daniel , Kawachi Ichiro
Published: July 2005

Objective:To investigate individual level determinants of self rated health and happiness, as well as the extent of community level covariation in health and happiness.

Design:Multivariate multilevel regression analysis of self rated poor health and unhappiness at level 1, nested within 24 118 people at level 2, nested within 36 communities at level 3. Data were obtained from the 2000 social capital benchmark survey.

Setting:USA communities.

Participants:24 118 adults.

Main outcome measures:Self reported fair/poor health; and a single item measure of subjective wellbeing.

Results:Controlling for demographic markers, a strong income and education gradient was seen for self rated poor health and unhappiness, with the gradient being stronger for poor health. Community level correlations between self rated poor health and happiness were stronger (0.65) than the individual level correlations (0.16) between the two outcomes.

Conclusion:Poor health and unhappiness are highly positively correlated within individuals, and communities that are healthier tend to be happier and vice versa.
Flow and heat transfer of a couple-stress fluid sandwiched between viscous fluid layers
Authors: Umavathi J C , Chamkha A J , Manjula M H , Al-Mudhaf A
Published: July 2005

The problem of steady laminar fully developed flow and heat transfer in a horizontal channel consisting of a couple-stress fluid sandwiched between two clear viscous fluids is analyzed analytically. The fluids in all regions are assumed to be incompressible, immiscible, and the transport properties of the fluids in all regions are assumed to be constant. Under these assumptions, the resulting governing equations constitute a set of coupled linear ordinary differential equations that is solved analytically. The closed form solutions obtained for the velocity and temperature fields in the channel are evaluated numerically for various parametric conditions. These results are illustrated graphically to illustrate the effects of the physical parameters governing the flow such as the viscosity ratio, conductivity ratio, couple-stress parameter, Eckert number, and the Prandtl number on the velocity and temperature profiles. In addition, results for the rate of heat transfer are computed for different values of the physical parameters and presented in tabular form. It is found that the effect of the couple stress parameter is to promote the motion of the fluid.PACS Nos.: 44.15.+a
A second century of Einstein?BoseEinstein condensation and quantum information
Authors: van Wijngaarden W A
Published: July 2005

A century ago Albert Einstein transformed classical physics with his seminal papers on Brownian motion, the Photoelectric effect, and, of course, special and later general relativity. Lesser well-known are his contributions to BoseEinstein Condensation and the EinsteinPodolskyRosen paradox, the latter being a criticism of Quantum Mechanics. These later works were regarded even by physicists for decades as mere Gedanken or thought experiments. In recent years, not only have they been verified experimentally but revolutionary technological applications are emerging including quantum cryptography and possibly quantum computing. PACS Nos.: 03.65, 03.67, 03.75, 05.30.Jp
River otter hair structure facilitates interlocking to impede penetration of water and allow trapping of air
Authors: Weisel John W , Nagaswami Chandrasekaran , Peterson Rolf O
Published: July 2005

Unlike many other mammals spending a considerable amount of time in water, river otters (Lutra canadensis (Schreber, 1777)) do not have a thick layer of body fat. Instead, they have a very densely packed layer of thin underhairs. The structure of river otter hair was examined by scanning electron microscopy and polarizing light microscopy. Guard hairs were hollow and became thicker distally and then tapered to a point and had different cuticle scales in proximal and distal regions. The cuticle of the thin underhairs had a striking pattern of sharply sculpted fins with deep grooves between them; usually there were four fins at each level, rotated 45° with respect to those at an adjacent level. Underhairs varied in diameter and the scales were sometimes petal-shaped. Polarizing light microscopy images showed interlocking arrangements of the underhairs that help to impede the penetration of water. Also, these images showed that the grooves between fins or petals of underhairs entrap air bubbles. The structure of the hairs allows them to interact loosely with each other, despite variations in size and structure. Furthermore, the nature of the interactions between the fins and depressions allows space between the hairs that can trap air bubbles to increase the thermal insulation of the otter's coat.
Male harassment of female New Zealand sea lions, Phocarctos hookeri: mortality, injury, and harassment avoidance
Authors: Chilvers B Louise , Robertson Bruce C , Wilkinson Ian S , Duignan Padraig J , Gemmell Neil J
Published: July 2005

Sexual aggression by male pinnipeds during breeding can lead to female injury and death, affecting reproductive success, fecundity, and increasing the cost of mating for females. Thus, females that employ strategies to minimize the probability of being injured will be at an advantage. Here we investigate the extent of injuries and the number of deaths attributed to male harassment, and test the hypothesis of whether the arrival and departure behaviour of female New Zealand sea lions (Phocarctos hookeri (Gray, 1844); NZSL) at Sandy Bay, Enderby Island, the Auckland Islands, is adapted to reduce the chance of injury or death from encounters with male NZSLs. During the breeding season, harassment by non-territorial male NZSLs causes mortality in adult female NZSLs, approximately 5 in every 1000 females breeding each year. Permanent scars from male bites are observed on 84% of adult females. This mortality and visible injury rate only represents the direct impacts on female NZSL from male harassment. Indirect impacts, such as the time and energy cost of avoidance behaviour, pup separation, and pup injury and death, can have as significant long-term effects on individuals and the population. We find that male harassment can influence the behaviour of individuals in NZSL breeding harems.
Impacts of mosquitoes and black flies on defensive behaviour and microhabitat use of the North American porcupine (Erethizon dorsatum) in southern Quebec
Authors: Comtois Annie , Berteaux Dominique
Published: July 2005

Biting flies are known to influence the behaviour and microhabitat use of certain mammals. However, most studies were realized in open habitats. Our objective was to determine if mosquitoes (Culicidae) and black flies (Simuliidae) affect the behaviour and habitat use of a mammal typical of the boreal forest, the North American porcupine (Erethizon dorsatum (L., 1758)). The project was divided into three parts: (1) abundance of biting flies and their (2) direct effects (bites) and (3) indirect effects (repelling movements and microhabitat use) on porcupines. The abundance of insects was measured with CO2-baited traps. Ten male porcupines were followed by telemetry. Mosquitoes were more abundant on the ground than in the tree canopy and the opposite was observed for black flies. The biting flies were less abundant inside dens than outside. The quantity of bites on porcupines was correlated with the abundance of black flies. We observed frequent repelling movements that were associated with the presence of insects. Some microhabitats offered excellent protection against biting insects, but porcupines did not use these refuges to a greater extent at the peak of insect abundance. We conclude that, although biting flies had measurable impacts on the wounding rate and behaviour of porcupines, this did not translate into important shifts in habitat use.
Trace elements in tissues of phocid seals harvested in the Alaskan and Canadian Arctic: influence of age and feeding ecology
Authors: Dehn Larissa-A , Sheffield Gay G , Follmann Erich H , Duffy Lawrence K , Thomas Dana L , Bratton Gerald R , Taylor Robert J , O'Hara Todd M
Published: July 2005

Concentrations of selected trace elements (Ag, Cu, Cd, Se, Zn, THg, and MeHg) were measured in tissues of subsistence-harvested ringed (Pusa hispida (Schreber, 1775)), bearded (Erignathus barbatus (Erxleben, 1777)), and spotted (Phoca largha Pallas, 1811) seals from Alaska and ringed seals from Canada. Most variables differed significantly in tissues of phocids analyzed. Concentration of renal Cd was highest in ringed seals from Canada and bearded seals from Alaska, while spotted seals had the lowest concentrations. Concentrations of Cd increased with age to a maximum in ringed and bearded seals, followed by a slow decline with increasing age. Spotted seals had the highest proportion of MeHg to THg (%MeHg) in liver and bearded seals the lowest ratio. THg in seal tissues followed the opposite trend. %MeHg in ringed and bearded seals followed a hyperbolic decay function with age, but was highly variable in spotted seals. Seals with lesions had a higher relative occurrence of MeHg in liver. The molar ratio of Se:THg in liver exceeded 1:1 in most seals and was negatively correlated with age in ringed and spotted seals. Hepatic Ag was higher in bearded seals than in ringed and spotted seals. A correlation of Ag with age was not documented.
Timing and causes of mortality in the endangered Vancouver Island marmot (Marmota vancouverensis)
Authors: Bryant Andrew A , Page Rick E
Published: July 2005

We used radiotelemetry to evaluate seasonal survival rates and mortality factors for a critically endangered island endemic, the Vancouver Island marmot (Marmota vancouverensis Swarth, 1911). Recovery of radio transmitters and marmot remains suggested that predation was the major cause of mortality, accounting for at least 24 of 29 (83%) known-fate deaths recorded since radiotelemetry efforts began in 1992. Wolves (Canis lupus L., 1758) and cougars (Puma concolor (L., 1771)) apparently accounted for 17 deaths (59%). Three marmots (10%) were killed by golden eagles (Aquila chrysaetos (L., 1758)), four (14%) were killed by unknown predators that probably included all of the above species, two (7%) died from unknown causes, and three (10%) died during hibernation in a single burrow. Mortality rates varied seasonally. The daily probability of death during hibernation was very low (Pdeath = 0.016). The probability of death was also low from spring emergence through 31 July (Pdeath = 0.051), but was eight times higher in August (Pdeath = 0.395) and four times higher in September (Pdeath = 0.175). We concluded that predation was the proximate cause of recent declines in wild Vancouver Island marmot populations, that losses were highly concentrated in late summer, and that previous studies exaggerated the importance of winter mortality. We suggest that high predation rates were associated with forestry and altered predator abundance and hunting patterns.
Reproductive rates of wild and captive Vancouver Island marmots (Marmota vancouverensis)
Authors: Bryant Andrew A
Published: July 2005

I evaluated reproductive rates of the critically endangered Vancouver Island marmot (Marmota vancouverensis Swarth, 1911) using data from captive and wild populations over the 1980–2004 period. Results were similar to those reported for other alpine-dwelling marmots, including the closely related Marmota caligata (Eschscholtz, 1829) and Marmota olympus (Merriam, 1898). Most females in captivity first bred at age 3 or 4 (Tbreed = 4.3 years, SD = 1.15, n = 9), an age not significantly different from that observed in the wild (Tbreed = 3.6 years, SD = 1.2, n = 16). Numbers of pups weaned per litter were similar in captivity (Npups = 3.0, SD = 1.4, n = 25) and in the wild (Npups = 3.4, SD = 1.1, n = 58). Females were capable of weaning pups in consecutive years (46.4%, n = 13) but often skipped 1 year (39.3%, n = 11) or 2 years (14.3%, n = 4) between litters. Two-year-old females weaned pups infrequently (Pbreed = 0.09, n = 43) and older females were far more likely to breed (Pbreed = 0.40, n = 200); in neither case were significant captive-wild differences found. The oldest breeding female was 10 years old, but sample sizes for marmots older than 8 years were small and maximum breeding age may be underestimated. Between-litter intervals in captivity (Tbetween = 1.4 years, SD = 0.7, n = 11) were significantly shorter than in the wild (Tbetween = 1.9 years, SD = 0.7, n = 17). Sex ratios of weaned pups did not differ from 1:1 in the wild (female/male = 1.04) but were significantly skewed towards males in captivity (female/male = 0.56). I conclude that reproductive performance in Vancouver Island marmots is limited both by body condition and social constraints.
Multiple paternity in the western terrestrial garter snake, Thamnophis elegans
Authors: Garner Trenton W.J , Larsen Karl W
Published: July 2005

Multiple paternity may be a widespread phenomenon in snakes, but studies to date are inadequate for assessing the effect that phylogeny may have on paternity. Hypothetical mechanisms responsible for polyandry in snakes include intersexual conflicts and avoidance of genetic incompatibilities due to inbreeding. We analysed the offspring of six litters of western terrestrial garter snakes (Thamnophis elegans (Baird and Girard, 1853)) using microsatellite DNA polymorphisms. We directly detected multiple paternity in half of the litters, one of which exhibited triple paternity, and substantial skew of paternal contributions in all multiply sired litters. Females producing multiply sired offspring were heavier postpartum and produced larger litters, suggesting that larger females that invest more in reproduction are more likely to be multiply mated, a result supporting the hypothesis that polyandry is due to intersexual conflict. Continued investigations of paternity patterns within this genus are under way, but if the factors driving polyandry in snakes are to be identified, controlled laboratory crosses are required.
Flock formation and the role of plumage colouration in Ardeidae
Authors: Green M Clay , Leberg Paul L
Published: July 2005

It has been hypothesized that white plumage facilitates flock formation in Ardeidae. We conducted four experiments using decoys to test factors involved in attracting wading birds to a specific pond. The first three experiments tested the effects of plumage colouration, flock size, and species-specific decoys on flock formation. The fourth experiment examined intraspecific differences in flock choice between the two colour morphs of the reddish egret, Egretta rufescens (Gmelin, 1789). Wading birds landed at flocks of decoys more often than single or no decoys (P < 0.001) but exhibited no overall attraction to white plumage (P > 0.05). White-plumaged species were attracted to white decoys (P < 0.001) and dark-plumaged species were attracted to dark decoys (P < 0.001). Snowy egrets (E. thula (Molina, 1782)), great egrets (Ardea alba L., 1758), and little blue herons (E. caerulea (L., 1758)) landed more often at ponds that contained decoys resembling conspecifics. At the intraspecific level, all observed reddish egrets selected flocks with like-plumaged decoys. Our results suggest that plumage colouration is an attractant for species with similar plumage, but white plumage is not an attractant for all wading bird species. White plumage may facilitate flock formation in certain species but does not serve as a universal attractant for wading birds of varying plumage colouration and size.
Demography and reproductive ecology of the Columbia spotted frog (Rana luteiventris) across the Palouse
Authors: Davis Abbey B , Verrell Paul A
Published: July 2005

Here we report on the demography and reproductive ecology of the Columbia spotted frog (Rana luteiventris Thompson, 1913) breeding in ponds across the Palouse Bioregion of Washington and Idaho. Spotted frogs are unusual, if not unique, among temperate ranids in that males establish the oviposition site before females become active. Females laid at one or two communal sites in shallow water. Our breeding populations were small, never exceeding 50 adults counted, and most displayed male-biased sex ratios. We estimated effective population sizes (Ne) as ranges determined by extremes in male breeding success; these varied between 3.2 and 37.8. Even the latter falls below the minimum required for long-term population viability. Small population size may make spotted frogs vulnerable to genetic problems and environmental insults. Communal oviposition certainly renders a population's reproductive effort vulnerable to variation in hydroperiod, which we observed during the dry spring of 2004. In the absence of information on the degree of "connectedness" among our ponds as subunits of more resilient metapopulations, we suggest that small population size and communal oviposition likely render R. luteiventris vulnerable to anthropogenic disturbance. Furthermore, the status of R. luteiventris on the Palouse may be less secure than assumed currently.
Tracing dietary protein in red-backed voles (Clethrionomys gapperi) using stable isotopes of nitrogen and carbon
Authors: Sare David T.J , Millar John S , Longstaffe Frederick J
Published: July 2005

We examined the stable isotopes of nitrogen and carbon in a small mammal, the red-backed vole (Clethroinomys gapperi (Vigors, 1830)), to determine if isotope signatures reflect diet composition. Nitrogen- and carbon-isotope ratios in tissues from voles maintained on different protein levels in the laboratory were compared with wild-trapped voles. The isotopic fractionation of dietary nitrogen and carbon was also examined as food was digested in the stomach, incorporated into bone collagen, bioapatite, and hair, and excreted as feces. Nitrogen and carbon isotopes were fractionated differently depending on the isotopic composition and protein content of the diet. δ15N and δ13C values appear to be influenced by factors in addition to diet, such as macronutrients metabolized for respiration, metabolic rate, and periods of protein shortage.
INVERTED REPEATS IN VIRAL GENOMES
Authors: SPANÒ M. , LILLO F. , MICCICHÈ S. , MANTEGNA R. N.
Published: July 2005

We investigate 738 complete genomes of viruses to detect the presence of short inverted repeats. The number of inverted repeats found is compared with the prediction obtained for a Bernoullian and for a Markovian control model. We find as a statistical regularity that the number of observed inverted repeats is often greater than the one expected in terms of a Bernoullian or Markovian model in several of the viruses and in almost all those with a genome longer than 30,000 bp.
NONVANISHING OF THE RAMANUJAN TAU FUNCTION IN SHORT INTERVALS
Authors: ALKAN EMRE , ZAHARESCU ALEXANDRU
Published: July 2005

We provide new estimates for the gap function of the Delta function and for the number of nonzero values of the Ramanujan tau function in short intervals.
ON THE SERIES EXPANSION OF THE GÖLLNITZ–GORDON CONTINUED FRACTION
Authors: CHEN SIN-DA , HUANG SEN-SHAN
Published: July 2005

We give combinatorial interpretations of the coefficients in the series expansions of the Göllnitz–Gordon continued fraction and its reciprocal. These combinatorial results enable us to determine the signs of the coefficients. At the end, we also derive some interesting identities involving the coefficients.
2-ADIC PROPERTIES OF CERTAIN MODULAR FORMS AND THEIR APPLICATIONS TO ARITHMETIC FUNCTIONS
Authors: ONO KEN , TAGUCHI YUICHIRO
Published: July 2005

It is a classical observation of Serre that the Hecke algebra acts locally nilpotently on the graded ring of modular forms modulo 2 for the full modular group. Here we consider the problem of classifying spaces of modular forms for which this phenomenon continues to hold. We give a number of consequences of this investigation as they relate to quadratic forms, partition functions, and central values of twisted modular L-functions.
LOCAL MONODROMY OF p-ADIC DIFFERENTIAL EQUATIONS: AN OVERVIEW
Authors: KEDLAYA KIRAN S.
Published: July 2005

This primarily expository article collects together some facts from the literature about the monodromy of differential equations on a p-adic (rigid analytic) annulus, though often with simpler proofs. These include Matsuda's classification of quasi-unipotent ∇-modules, the Christol–Mebkhout construction of the ramification filtration, and the Christol–Dwork Frobenius antecedent theorem. We also briefly discuss the p-adic local monodromy theorem without proof.
NEURONAL SUBSTRATES OF COMPLEX BEHAVIORS IN C. ELEGANS
Authors: Bono Mario de , Villu Maricq Andres
Published: July 2005

A current challenge in neuroscience is to bridge the gaps between genes, proteins, neurons, neural circuits, and behavior in a single animal model. The nematode Caenorhabditis elegans has unique features that facilitate this synthesis. Its nervous system includes exactly 302 neurons, and their pattern of synaptic connectivity is known. With only five olfactory neurons, C. elegans can dynamically respond to dozens of attractive and repellant odors. Thermosensory neurons enable the nematode to remember its cultivation temperature and to track narrow isotherms. Polymodal sensory neurons detect a wide range of nociceptive cues and signal robust escape responses. Pairing of sensory stimuli leads to long-lived changes in behavior consistent with associative learning. Worms exhibit social behaviors and complex ultradian rhythms driven by Ca2+ oscillators with clock-like properties. Genetic analysis has identified gene products required for nervous system function and elucidated the molecular and neural bases of behaviors.
OPTICAL IMAGING AND CONTROL OF GENETICALLY DESIGNATED NEURONS IN FUNCTIONING CIRCUITS
Authors: Miesenböck Gero , Kevrekidis Ioannis G.
Published: July 2005

Proteins with engineered sensitivities to light are infiltrating the biological mechanisms by which neurons generate and detect electrochemical signals. Encoded in DNA and active only in genetically specified target cells, these proteins provide selective optical interfaces for observing and controlling signaling by defined groups of neurons in functioning circuits, in vitro and in vivo. Light-emitting sensors of neuronal activity (reporting calcium increase, neurotransmitter release, or membrane depolarization) have begun to reveal how information is represented by neuronal assemblies, and how these representations are transformed during the computations that inform behavior. Light-driven actuators control the electrical activities of central neurons in freely moving animals and establish causal connections between the activation of specific neurons and the expression of particular behaviors. Anchored within mathematical systems and control theory, the combination of finely resolved optical field sensing and finely resolved optical field actuation will open new dimensions for the analysis of the connectivity, dynamics, and plasticity of neuronal circuits, and perhaps even for replacing lost—or designing novel—functionalities.
Somatic vs. dendritic responses to hypercapnia in chemosensitive locus coeruleus neurons from neonatal rats
Authors: Ritucci Nick A. , Dean Jay B. , Putnam Robert W.
Published: July 2005

Cardiorespiratory control is mediated in part by central chemosensitive neurons that respond to increased CO2 (hypercapnia). Activation of these neurons is thought to involve hypercapnia-induced decreases in intracellular pH (pHi). All previous measurements of hypercapnia-induced pHi changes in chemosensitive neurons have been obtained from the soma, but chemosensitive signaling could be initiated in the dendrites of these neurons. In this study, membrane potential ( Vm) and pHi were measured simultaneously in chemosensitive locus coeruleus (LC) neurons from neonatal rat brain stem slices using whole cell pipettes and the pH-sensitive fluorescent dye pyranine. We measured pHi from the soma as well as from primary dendrites to a distance 160 μm from the edge of the soma. Hypercapnia [15% CO2, external pH (pHo) 7.00; control, 5% CO2, pHo 7.45] resulted in an acidification of similar magnitude in dendrites and soma (∼0.26 pH unit), but acidification was faster in the more distal regions of the dendrites. Neither the dendrites nor the soma exhibited pHi recovery during hypercapnia-induced acidification; but both regions contained pH-regulating transporters, because they exhibited pHi recovery from an NH4Cl prepulse-induced acidification (at constant pHo 7.45). Exposure of a portion of the dendrites to hypercapnic solution did not increase the firing rate, but exposing the soma to hypercapnic solution resulted in a near-maximal increase in firing rate. These data show that while the pHi response to hypercapnia is similar in the dendrites and soma, somatic exposure to hypercapnia plays a major role in the activation of chemosensitive LC neurons from neonatal rats.
Relationship of gastric emptying and volume changes after a solid meal in humans
Authors: Burton Duane D. , Kim H. Jae , Camilleri Michael , Stephens Debra A. , Mullan Brian P. , O’Connor Michael K. , Talley Nicholas J.
Published: July 2005

Noninvasive imaging has been developed to measure gastric volumes. The relationship between gastric emptying and volume postprandially is unclear. The aims were to 1) develop a 3-dimensional (3D) single photon emission-computed tomography (SPECT) method to simultaneously measure gastric volume and emptying postprandially, 2) describe the course of gastric volume change during emptying of the meal, and 3) assess a 3D method measuring gastric emptying. In 30 healthy volunteers, we used 111In-planar and 99mTc-SPECT imaging to estimate gastric emptying and volume after a radiolabeled meal. A customized analysis program of SPECT imaging assessed gastric emptying. A Bland-Altman plot assessed the performance of the new SPECT analysis compared with planar analysis. Gastric volume postprandially exceeds the fasting volume plus meal volume. The course of volume change and gastric emptying differ over time. Higher differences in volumes exist relative to fasting plus residual meal volumes at 15 min (median 763 vs. 568 ml, respectively, P < 0.001), 1 h (median 632 vs. 524 ml, P < 0.001), and 2 h (median 518 vs. 428 ml, P < 0.02), in contrast to similar volumes at 3 h (median 320 vs. 314 ml, P = 0.85). Analysis of SPECT imaging accurately measures gastric emptying compared with planar imaging with median differences of 1% (IQR −2.25 to 2.0) at 1 h, 1% (−3.25 to 2.25) at 2 h, and −2.5% (−4 to 0) at 3 h. Gastric volume exceeds meal volume during the first 2 postprandial hours, and simultaneous measurements of gastric volume and emptying can be achieved with a novel 3D SPECT method.
Spatial and temporal coupling between slow waves and pendular contractions
Authors: Lammers Wim J. E. P.
Published: July 2005

In contrast to the mechanisms of segmental and peristaltic contractions in the small intestine, not much is known about the mechanism of pendular contractions. High-resolution electrical and mechanical recordings were performed from isolated segments of the rabbit ileum during pendular contractions. The electrical activities were recorded with 32 extracellular electrodes while motility was assessed simultaneously by video tracking the displacements of 20–40 serosal markers. The electrical activities consisted of slow waves, followed by spikes, that propagated in either the aboral or oral direction. The mechanical activity always followed the initial electrical activity, describing a contraction phase in one direction followed by a relaxation phase in the opposite direction. Pendular displacements were always in rhythm with the slow wave, whereas the direction of the displacements was dictated by the origin of the slow wave. If the slow wave propagated aborally, then the pendular displacement occurred in the oral direction, whereas if the slow wave propagated in the oral direction, then the displacement occurred in the aboral direction. In the case of more complex propagation patterns, such as in the area of pacemaking or collision, direction of displacements remained always opposite to the direction of the slow wave. In summary, the direction and pattern of propagation of the slow wave determine the rhythm and the direction of the pendular motility. The well-known variability in pendular movements is caused by the variability in the propagation of the underlying slow wave.
Autocrine regulation of internal anal sphincter tone by renin-angiotensin system: comparison with phasic smooth muscle
Authors: De Godoy Márcio A. F. , Rattan Satish
Published: July 2005

The myogenic control mechanisms that govern the basal tone in the internal anal sphincter (IAS) are not known. The present studies determined the autocrine regulation of ANG II in the IAS. The studies were performed in the freshly isolated smooth muscle cells (SMC) of the IAS. We determined the presence of ANG II precursor angiotensinogen (Angen), and the enzymes that convert it into ANG II, using functional, molecular biology, and immunocytochemical studies in rats. ANG II levels in the SMC were determined using ELISA. The IAS SMC generate ANG II at a rate severalfold higher than those from the adjoining smooth muscle of rectum (RSM). RT-PCR data show that IAS exclusively expresses significant higher levels of renin, Angen, and angiotensin-converting enzyme (ACE). These data were confirmed using Western blot analyses and immunocytochemistry. In the IAS SMC, H-77 (10 μM; renin inhibitor) and captopril (1 μM; ACE inhibitor) decreased the basal as well as Angen-increased levels of ANG II. The following functional data corroborate the role of renin-angiotensin system (RAS) in the IAS tone. Angen produced concentration-dependent shortening of the IAS SMC that was inhibited by H-77 and captopril. In addition, H-77 or captopril caused a concentration-dependent fall in the IAS tone vs. nontonic tissues. Basal tone in IAS is partially under the autocrine control of cellular RAS evident by the expression of mRNA coding Angen, renin, and ACE and translation to the respective proteins in the SMC.
Gastrointestinal Stem Cells I. Pancreatic stem cells
Authors: Soria Bernat , Bedoya Francisco J. , Martin Franz
Published: July 2005

The transplantation of islets isolated from donor pancreas has renewed the interest in cell therapy for the treatment of diabetes. In addition, the capacity that stem cells have to differentiate into a wide variety of cell types makes their use ideal to generate β-cells for transplantation therapies. Several studies have reported the generation of insulin-secreting cells from embryonic and adult stem cells that normalized blood glucose values when transplanted into diabetic animal models. Finally, although much work remains to be done, there is sufficient evidence to warrant continued efforts on stem cell research to cure diabetes.
Waveform dispersion, not reflection, may be the major determinant of aortic pressure wave morphology
Authors: Hope Sarah A. , Tay David B. , Meredith Ian T. , Cameron James D.
Published: July 2005

The objective of this study was to investigate the determinants of aortic pressure waveform morphology in the thoracoabdominal aorta with specific reference to features of potential prognostic value for cardiovascular disease. In particular, we aimed to determine the location of major pressure wave reflection sites within the aorta. Aortic pressure waveforms were acquired with 2-Fr Millar Mikro-tip catheter transducers in 40 subjects (26 men, 14 women), and repeated in 10 subjects, at five predetermined points within the aorta: aortic root, transverse arch, and at the levels of the diaphragm, renal arteries, and aortic bifurcation. Waveforms were analyzed for augmentation index (AI), time to inflection point ( Ti), and pressure parameters. AI decreased progressively between the aortic root and bifurcation ( P < 0.001), and Ti increased ( P < 0.01). There was the expected progressive peripheral amplification of systolic and pulse pressures and fall in time to peak pressure (all P < 0.001). There was no difference on repeat pullback or between sexes. These data are at variance with the concept that central AI results solely from pressure wave reflection, when Ti would be expected to decrease and AI increase with distal progression. Pressure wave propagation phenomena may contribute, and the potential role of frequency dispersion merits investigation.