bluuebunny/crossref_metadata_2025 huggingface dataset:
Treefrog toe pads: comparative surface morphology using scanning electron microscopy
Authors: Green David M.
Published: August 2008

Scanning electron microscopy of toes and toe pads of a large number of species of frogs reveals many features of possible systematic or functional significance. The adhesive pads evolved through progressive development of specialized columnar epidermis at the digital tips, in tandem with increased arborealism. Mucous pore morphology and density on the pads will distinguish between evolutionarily convergent hylid and rhacophorid treefrogs. Larger pads and accessory adhesive areas on subarticular tubercles allow large treefrogs to compensate for allometric increase in mass relative to surface area. Other characters of potential systematic or evolutionary significance are discussed. As anuran toe pads have been used previously for systematics, the use of scanning electron microscopy in this regard is advocated.
Aggression, superterritories, and reproductive success in tree swallows
Authors: Harris Reid N.
Published: August 2008

The relationship between territorial aggression and reproductive success was studied on a well-established, insular population of tree swallows. Four treatments of nest boxes that differed in interbox distances were created. Short interbox distances significantly reduced the occupancy of nest boxes both between and within years. Swallows in short interbox distance treatments defended more than one nest box, which was an additional resource not necessary for their successful reproduction. Excluded potential breeders attempted to colonize vacant boxes within another swallow's territory throughout the nestling period, but were usually prevented by the aggression of the resident pair. Aggressive activity had no direct effect on three measures of a swallow's reproductive output: percent young fledged, nestling growth, and fledgling weights. The concept of intraspecific aggressive neglect is questioned. However, by excluding potential breeders from nesting, for whatever reason, breeding tree swallows increased their relative genetic contribution to future generations.
The contractile vacuole of Amoeba proteus. III. Effects of inhibitors
Authors: Ahmad Mukhtar
Published: August 2008

The effects of cyanide and malonate have been observed on the fine kinetics of the contractile vacuole of Amoeba proteus. Brief exposure to cyanide does not produce any inhibition of vacuolar output rate. Only after keeping the amoeba in cyanide solution for long periods (9 h) and renewing the inhibitor solution frequently was significant (76%) inhibition of output rate observed. Owing to this reduction in output rate, the volume of the organism doubles in approximately 9 h. Malonate induces mild (30%) inhibition of the vacuolar output. This inhibition normally is alleviated on return to original Chalkley's medium.It is concluded that the vacuolar operation in Amoeba proteus is an energy dependent phenomenon. Such energy can be derived from respiratory or glycolytic processes. However, the congregation of mitochondria around the contractile vacuole suggests that respiratory oxidation may be the chief source of energy supply. The cellular homeostasis is probably maintained through a Na+–K+ pump, operative in the vacuolar membrane.
Comparative demography of Clethrionomys rutilus in taiga and tundra in the low Arctic
Authors: Martell A. M. , Fuller W. A.
Published: August 2008

Our working hypothesis was that winter mortality of Clethrionomys rutilus would be more severe in tundra than in taiga, and in winters with "unfavorable" rather than "favorable" conditions during establishment or ablation of the snow cover or in the subnivean environment during midwinter. Vole mortality was higher in the tundra (90–95%) than in the taiga (55–75%), in accordance with our prediction, but year to year differences in snow conditions were not necessary determinants of winter survival during the 4 years of the study. Subnivean breeding was never detected. The onset of summer breeding was related to the time of snow melt, and a late spring was followed by a low rate of maturation of young-of-the-year females and small spring-to-fall increase in numbers. Few young of either sex matured in two of three summers in the taiga, whereas about half the females and one-third of the males matured each year on the tundra. Litters were significantly larger on the tundra and spring sex ratios were female biased. Thus reproductive output was high on the tundra, which would offset high winter losses. Intraspecific wounding was related to density and maturity except that on the tundra many immature young had bites. No superannual fluctuation was apparent on the tundra.
The feeding pattern and daily ration of a top carnivore, the northern pike (Esox lucius)
Authors: Diana James S.
Published: August 2008

Food habits, digestive rates, and daily ration were determined for 1290 northern pike (Esox lucius) collected from Lac Ste. Anne, Alberta. The data were used to develop a model for quantifying the daily ration of a top carnivore; the basic feature was that feeding time was short relative to time between meals. Pike diet included mainly perch (Perca flavescens), spottail shiners (Notropis hudsonius), burbot (Lota lota), and white suckers (Catostomus commersoni), in order by numerical importance. Caloric intake by pike depended mainly on perch, suckers, and burbot, in that order; the difference between the two rankings was due to differences in the size of individuals eaten. Gastric evacuation rate (determined by controlled experiment) was 48 h in summer and 12 days in winter. Daily ration was high from May to August (peaking in June) and very low in winter. Both sexes of pike exhibited a spawning fast in late April. Female rations were 1.5 to 2.3 times the male values in summer and winter. The rare inclusion of large prey items, such as suckers and burbot, had a very significant effect on the total caloric intake of pike.
Habitat selection by dabbling ducks in the Baie Noire marsh, southwestern Quebec
Authors: Courcelles Réal , Bédard Jean
Published: August 2008

We monitored the waterfowl distribution in a recently flooded 260-ha marsh along the Ottawa River during 1974 and 1975. The birds (the three most important species were the black duck. Anas rubripes; the mallard, A. platyrhynchos; and the blue-winged teal, A. discors) did not distribute randomly among the five major habitats recognized, but clearly preferred a habitat dominated physiognomically by broken cattail (Typha angustifolia) cover but best characterized ecologically by ivy-leaved duckweed (Lemna trisulca), whitish water-milfoil (Myriophyllum exalbescens), and common bladderwort (Utricularia vulgaris). On average, broods (0.3/ha) and adult birds (6.6/ha) were four times more abundant per hectare there than in the next best habitat. This pattern of use was stable throughout the summer and throughout the daylight period as well. Multivariate analysis (correspondence factor analysis) enabled us to extract those ecological variables that played a determinant role in controlling plant distribution throughout the marsh. The observational and analytical techniques developed in this work could be applied to the development of marsh management plans designed to promote the expansion of the preferred waterfowl habitat.
Artificial diets for sea hares
Authors: Carefoot Thomas H.
Published: August 2008

An artificial diet, made up principally of chemicals set in agar, has given good growth in the sea hare Aplysia dactylomela Rang (13 and 29% increases in live weight in two trials of 24- and 16-day periods, respectively, at 28.5 °C). Spawn production accounted for 65 and 29%, respectively, of these increases in weight. The role that such a diet may play in the study of nutrition and feeding preferences of sea hares and of other marine invertebrate herbivores is discussed.
Some problems in identification of origins of lesser snow geese by chemical profiles
Authors: Kelsall John P. , Burton Roland
Published: August 2008

Results are reported of experimental work done to clarify problems and unknowns involved in identifying origins of lesser snow geese through computer-controlled, X-ray spectrometric analyses of primary flight feathers. Materials from wild and captive populations of lesser snow geese (Chen caerulescens caerulescens) were used. The use of an X-ray tube source of irradiation was successfully introduced to previously described techniques. Practical investigation of sample size for the generation of discriminant functions suggests that 30 samples per population are a barely adequate minimum and that 40 or more should be used.Given adequate sample sizes, and suitably different populations, the classification process overrides differences attributable to sex, age, and "Feather year" with great accuracy. With small sample sizes, however, those differences will dampen the accuracy of discrimination and classification, as will increasing numbers of populations. Examination of feathers from a captive flock, maintained for 4 years, shows statistically insignificant sexual differences, significant "within-year" changes in feather chemistry between October and May, and moderately consistent discrimination between year classes. Some of the chemical variables involved in the observed differences are examined.
Morphometric variability in larvae of the Antarctic fly, Belgica antarctica (Diptera: Chironomidae)
Authors: Atchley William R. , Hilburn Larry R.
Published: August 2008

Morphometric variability is examined in the larval head capsule of the midge Belgica antarctica Jacobs (Diptera: Chironomidae). This species is the southernmost free-living holometabolous insect and occurs over about a 650-km range on the western side of the Antarctic Peninsula. Highly significant differences were found between samples and between sexes for nine larval head capsule characters. No morphometric effect was found due to chromosomal inversion heterozygosity. The expression of sexual dimorphism was found to vary greatly between samples. Some samples exhibited no sexual dimorphism whereas others exhibited highly complex patterns of sexual dimorphism. Attempts to relate morphometric variability to geographic and ecological parameters met with only limited success. No correspondence was noted between the classification of samples based on inversion heterozygosity and that based on larval morphology.
Annual maturation of Paramphistomum cervi (Trematoda: Paramphistomatidae) in moose, Alces alces L.
Authors: Lankester Murray W. , Snider J. Barry , Jerrard Robert E.
Published: August 2008

Rumen flukes, presumably Paramphistomum cervi (Schrank 1790), were found in the rumen of 49 of 60 moose (82%) examined from 1976 to 1979. Most flukes from moose killed during winter (November–March) were small and immature, whereas almost all were gravid from moose killed during summer (July–August). Mature worms apparently die during September and October. Moose probably become infected with paramphistomes while feeding intensively on aquatic vegetation during June and July. The sexual maturation of rumen flukes may be initiated by changes in the diet of moose in late winter or spring.
Indices of structural size and condition of American wigeon (Anas americana)
Authors: Wishart Richard A.
Published: August 2008

American wigeon (Anas americana) were studied throughout their annual cycle in British Columbia, Saskatchewan, and Manitoba between 1976 and 1978. Body measurements were obtained from 145 collected and 128 livetrapped birds. Collected birds were dissected and analyzed for lipid, protein, and water content, and organs and muscles were weighed. Similar measurements were made on two each of starved adult captive males and females to determine basal levels of reserves. The skeletons were excised from 13 other wigeon and the lipid-free dry weights of bone were determined. Body length + wing length was the best predictor of skeletal weight and could be used as a structural index (SI). Body weight varied greatly over the year and so is a poor indicator of structural size. The lipid and protein reserves were calculated and the total reserve weight was used as the condition index (CI) for each bird. Body weight/SI was a good predictor of CI but better estimates were obtained with plucked, eviscerated carcass weights. The best predictors of lipid reserves and protein reserves were weights of abdominal fat + skin fat and carcass weight/SI, respectively.
Growth dynamics of muscle fibres, dry weight, and condition in relation to somatic growth rate in yearling rainbow trout (Salmo gairdneri)
Authors: Weatherley A. H. , Gill H. S. , Rogers S. C.
Published: August 2008

Rainbow trout (15.5 cm) fed "ad lib." rations grew a little faster at 12 °C than at 16 °C, and both groups grew much faster than a third group at 12 °C receiving "3–4%" rations. Growth of the mosaic muscle mass was characterized by increase in fibre mean diameter, though most bulk increase (up to 25 cm or more) resulted from increase in fibre number. Fibre diameter: fish length was least in the fastest growing trout (12 °C ad lib.), signifying their greater ability to add new fibres during growth compared with the slower growing trout; diameter range increased markedly among trout > 18 cm long, but small fibres (< 20 μm) persisted in diminishing numbers even in the largest trout. In the 12 °C ad lib. trout, condition (K) correlated with length and fibre diameter; in the slower growing groups K was more influenced by mean fibre diameter. A higher asymptote of K occurred at greater length in the fastest growing group than in the two slower growing groups. Percent dry weight: length was greater for 16 °C ad lib. than for the fastest or slowest growth groups; absolute dry weight: length ratios were similar for 12 °C and 16 °C ad lib. trout; both exceeded those for the 12 °C 3-4% group.
Shallow-water comatulid crinoids (Echinodermata) from Barbados, West Indies
Authors: Liddell W. David
Published: August 2008

The shallow-water crinoid fauna of the northwest coast of Barbados consists of six species: Analcidometra armata (Pourtalès), Nemaster discoidea (P. H. Carpenter), Nemaster rubiginosa (Pourtalès), Comactinia echinoptera (J. Müller), Ctenantedon kinziei Meyer, and Tropiometra carinata (Lamarck). Of these, only the first three may be regarded as common. The highest concentrations of crinoids occur along the seaward slope of the bank reef, which parallels the coast. Here the combined densities of crinoids over large areas may reach 1.15/m2, which is comparable with or higher than densities found elsewhere in the Caribbean. The co-occurring Nemaster discoidea and Nemaster rubiginosa exhibit broadly overlapping bathymetric ranges and habitat utilization patterns. Of the more common species, Analcidometra armata alone shows a restricted bathymetric distribution and a unique substrate type (an exposed position on the gorgonian Pseudopterogorgia sp.).
Behaviour of unpaired male black ducks (Anas rubripes) during the breeding season in a Nova Scotia tidal marsh
Authors: Seymour Norman R. , Titman Rodger D.
Published: August 2008

Behaviour of unpaired male black ducks throughout the breeding season was studied for 3 years (1973, 1974, 1978) in the marsh of a tidal estuary near Antigonish, Nova Scotia. Males remained primarily on a communal area in the marsh. Reproductively oriented activities occurred from late March until late May and peaked in frequency and intensity in early April. Most frequently daily display occurred from 0800 to 1300 hours. Unpaired males joined pairs singly or in groups but only grouped birds courted females. Unpaired males were tolerated on territories and some single males associated with pairs for several days. Groups joined pairs that foraged on the communal area, often persisting with them and disrupting their activity. Males appeared to prefer to court introduced unpaired females over paired females, which were always with their mates. Some males appeared successful in forming pair bonds with introduced females. Males did not attempt to rape females either on territories or the communal area and mallard (A. platyrhynchos) and pintail (A. acuta) males courted female black ducks.
Patterns of initial benthic recolonization of a reclaimed coal strip-mined river channel
Authors: Gore James A.
Published: August 2008

Benthic macroinvertebrate samples were taken at sampling stations upstream of, downstream of, and within a newly opened channel of the Tongue River in Wyoming. The channel, reclaimed from coal strip-mining, contained layers of topsoil, gravel, and small to medium cobble. Benthic recolonization progressed towards maximum densities following terms of a power function. The mayflies of the genus Baetis were the primary colonizers. Colonization occurred primarily by drift of aquatic insects and algal mats in the first 14 days of channel opening. Some upstream migration, particularly by the dragonfly Ophiogomphus, was observed. Attainment of maximum diversity lagged density by 20 to 30 days. This period represented a time of dynamic adjustment within the community to match the undisturbed source area communities. The combined effects of differential drift rates and distances for aquatic insects and detrital material were responsible for the rather predictable patterns of colonization as well as the sequentially decreasing diversity values as distance from the upstream source areas increased.
The influence of temperature and anaemia on the adrenergic and cholinergic mechanisms controlling heart rate in the rainbow trout
Authors: Wood Chris M. , Pieprzak Patricia , Trott J. N.
Published: August 2008

The capacity for cardioacceleration by adrenergic and cholinergic mechanisms was studied in resting rainbow trout, Salmo gairdneri, at 5, 12, and 20 °C. The trout were fitted with chronic dorsal aortic catheters for heart rate and blood pressure measurements. At all three temperatures, muscarinic cholinergic blockade with atropine caused substantial tachycardia, thereby indicating the presence of cholinergic vagal tone in resting animals. The relative effect of atropine was significantly greater at 5 °C (+53% of resting heart rate) than at 12 and 20 °C (≈ +30%). Maximal adrenergic stimulation (via adrenaline) after atropine caused a small further cardioacceleration at all temperatures. The adrenaline effect increased significantly from +8% (of resting heart rate) at 5 °C to +15% at 20 °C. The findings provide qualified support for the hypothesis that a reduction in vagal cholinergic activity is relatively more important in tachycardia at low temperature, and that adrenergic stimulation is relatively more important at high temperature, although the cardioacceleratory capacity of the cholinergic mechanism remains dominant throughout. The increase in heart rate accompanying experimental anaemia (haematocrit ≤ 6%) at all three temperatures was almost entirely due to a removal of vagal cholinergic tone; the contribution of adrenergic mechanisms, if any, was small.
Diel patterns of fanning activity, egg respiration, and the nocturnal behavior of male three-spined sticklebacks, Gasterosteus aculeatus L. (f. trachurus)
Authors: Reebs S. G. , Whoriskey Jr. F. G. , FitzGerald G. J.
Published: August 2008

Observations of male three-spined stickleback (Gasterosteus aculeatus L.) parental care were made in a salt-marsh tide pool at 3-h intervals over 24-h cycles, to determine if male behavior varied in association with diel changes in water temperature and dissolved oxygen concentration. An analysis of egg metabolism in situ revealed positive correlations between rate of egg oxygen consumption and egg age, water temperature, and dissolved oxygen levels, while there was a slight but significant negative correlative with the number of eggs per nest. We found no significant difference when we compared the proportion of time males spent fanning their nests during the day with night levels. However, nocturnal fanning bouts were significantly longer and less numerous than diurnal ones. In contrast to the rest of the 24-h cycle, the males remained inactive between fanning bouts at night, except when exposed to hypoxic conditions
Retinal development in larval and juvenile European eel, Anguilla anguilla (L.)
Authors: Pankhurst N. W.
Published: August 2008

Retinal structure was examined in 50-mm long leptocephalus larvae and in glass eel to elver juvenile stages. Larvae were found to have a single rodlike photoreceptor, while all postmetamorphic stages displayed a duplex retina. Retinal cell densities or ratios were not found to change with ontogeny in juveniles. Maintenance of juveniles in constant light or constant darkness resulted in a significant increase in numbers of rods and a decrease in numbers of inner nuclear layer cells, respectively. Retinomotor responses were present in all juvenile eels examined. The functional significance of retinal structure is discussed in relation to the different habitats occupied by successive life-history stages.
The cytotaxonomy of three species in the jenningsi-group of the subgenus Simulium (Diptera: Simuliidae) in New York State
Authors: Gordon A. Elizabeth
Published: August 2008

The chromosomal constitutions of three species in the jenningsi-group in the Adirondacks and the Finger Lakes Region in New York State are detailed. No sibling species were found in Simulium jenningsi, S. fibrinflatum, or S. luggeri in these areas. The species were found to differ by 6 fixed inversions and by 19 floating inversions. 4 of which are related to sex determination in S. jenningsi. The major chromosomal differences between the venustutm-group and the jenningsi-group are detailed. The ancestral condition for each arm was determined using ex-group and L′ analyses. A phylogenetic sequence for these three species from the ancestral condition is proposed.
Nestling feeding rates and body size of adult House Sparrows
Authors: McGillivray W. Bruce
Published: August 2008

Much of the variance in feeding rates of nestlings by adult House Sparrows (Passer domesticus) at Calgary, Alberta appears to be due to individual variation in the quality of the parents. Males contribute less to nestling feeding than do males at other localities. The body size and sexual size dimorphism of House Sparrows has been shown to increase with increasing latitude in North America. Hence, sparrows at Calgary are larger than average and there is a suggestion that the relative contribution by the sexes is related to male size and concomitant energetic limitations. The relationship between weight and body size is strong in the fall for both male and female House Sparrows but is poor during the breeding season. Adult females, but not males, increase their nestling feeding rate in inclement weather.
Structure, frequency of usage, and apparent learning in the primary song of the yellow-throated vireo, with comparative notes on solitary vireos (Aves: Vireonidae)
Authors: James Ross D.
Published: August 2008

The primary song of 27 yellow-throated vireos (Vireo flavifrons) from throughout their breeding range in eastern North America was examined spectrographically. Only 39 different song phrases were found, and each bird sang an average of only 5 phrases. There is, therefore, a great deal of overlap in the phrases sung by birds in any part of their range. Yellow-throated vireo primary song phrases are characteristically frequency modulated like those of the solitary vireos (Vireo solitarius) of western North America, but no phrases of the two species were identical. Male yellow-throated vireos sang a number of the same few song phrases at different times during the breeding season. Distinct changes in timing and the overall amount of singing, however, indicate the importance of these two factors for intraspecific communication. The discovery of a yellow-throated vireo singing primary song phrases characteristic of solitary vireo song seems to indicate that, to a large extent, primary song is learned, and that much of the learning takes place early in the bird's life.
Faecal nitrogen as an index of hare browse quality
Authors: Pehrson Åke
Published: August 2008

Experiments with caged mountain hares fed natural winter browse are examined to test the applicability of faecal nitrogen as an index of the nutritional quality of winter hare browse. The weak correlation found between faecal nitrogen concentration and weight balances of hares suggests that faecal nitrogen is not a reliable index of winter food nutritive quality. It is suggested that the lack of food selection based on nitrogen concentration is the main reason for this weak relationship.
QUANTUM OPTICS NETWORKS, UNITARY OPERATORS AND COMPUTER ALGEBRA
Authors: STEEB WILLI-HANS , HARDY YORICK
Published: August 2008

In linear quantum optics we consider phase shifters, beam splitters, displacement operations, squeezing operations etc. The evolution can be described by unitary operators using Bose creation and annihilation operators. This evolution can be reduced to matrix multiplication using unitary matrices. We derive these evolutions for the different unitary operators. Finally a computer algebra implementation is provided.
EVOLVING MODEL OF SCALE-FREE NETWORKS WITH INTRINSIC LINKS
Authors: GENG XIANMIN , WEN GUANGHUI , WANG YING , LI JINXIA
Published: August 2008

In this paper, we introduce the concept of intrinsic link, which is used to describe the intrinsic interactions between the individuals in complex systems. Furthermore, we present a model for the evolution of complex networks, in which the system dynamics motivated by four mechanisms: the addition of new nodes with preferential attachment, the addition of new nodes with intrinsic attachment, the addition of new links with preferential attachment and the addition of new intrinsic links. The model yields scale-free behavior for the degree distributions as confirmed in many real networks. With continumm theory, we get the analytical expressions of the degree distribution and the scaling exponent γ. The analytical expressions are in good agreement with the numerical simulation results.
FINITE TEMPERATURE SU(2) GAUGE THEORY: CRITICAL COUPLING AND UNIVERSALITY CLASS
Authors: VELYTSKY ALEXANDER
Published: August 2008

We examine SU(2) gauge theory in 3 + 1 dimensions at finite temperature in the vicinity of critical point. For various lattice sizes in time direction (Nτ = 1, 2, 4, 8) we extract high precision values of the inverse critical coupling and critical values of the 4th order cumulant of Polyakov loops (Binder cumulant). We check the universality class of the theory by comparing the cumulant values to that of the 3D Ising model and find very good agreement. The Polyakov loop correlators for the indicated lattices are also measured and the string tension values extracted. The high precision values of critical coupling and string tension allow us to study the scaling of dimensionless [Formula: see text] ratio. The violation of scaling by < 10% is observed as the coupling is varied from weak to strong coupling regime.
MICROSCOPIC SPIN MODEL FOR THE STOCK MARKET WITH ATTRACTOR BUBBLING ON REGULAR AND SMALL-WORLD LATTICES
Authors: KRAWIECKI A.
Published: August 2008

A multi-agent spin model for changes of prices in the stock market based on the Ising-like cellular automaton with interactions between traders randomly varying in time is investigated by means of Monte Carlo simulations. The structure of interactions has topology of a small-world network obtained from regular two-dimensional square lattices with various coordination numbers by randomly cutting and rewiring edges. Simulations of the model on regular lattices do not yield time series of logarithmic price returns with statistical properties comparable with the empirical ones. In contrast, in the case of networks with a certain degree of randomness for a wide range of parameters the time series of the logarithmic price returns exhibit intermittent bursting typical of volatility clustering. Also the tails of distributions of returns obey a power scaling law with exponents comparable to those obtained from the empirical data.
Platelets undergo phosphorylation of Syk at Y525/526 and Y352 in response to pathophysiological shear stress
Authors: Speich Henry E. , Grgurevich Svetozar , Kueter Teddi J. , Earhart Angela D. , Slack Steven M. , Jennings Lisa K.
Published: August 2008

Atherosclerotic plaques can lead to partial vascular occlusions that produce abnormally high levels of arterial wall shear stress. Such pathophysiological shear stress can promote shear-induced platelet aggregation (SIPA), which has been linked to acute myocardial infarction, unstable angina, and stroke. This study investigated the role of the tyrosine kinase Syk in shear-induced human platelet signaling. The extent of Syk tyrosine phosphorylation induced by pathophysiological levels of shear stress (100 dyn/cm2) was significantly greater than that resulting from physiological shear stress (10 dyn/cm2). With the use of phospho-Syk specific antibodies, these data are the first to show that key regulatory sites of Syk at tyrosines 525/526 (Y525/526) and tyrosine 352 (Y352) were phosphorylated in response to pathophysiological shear stress. Increased phosphorylation at both sites was attenuated by pharmacological inhibition of Syk using two different Syk inhibitors, piceatannol and 3-(1-methyl-1H-indol-3-yl-methylene)-2-oxo-2,3-dihydro-1H-indole-5-sulfonamide (OXSI-2), and by inhibition of upstream Src-family kinases (SFKs). Shear-induced response at the Syk 525/526 site was ADP dependent but not contingent on glycoprotein (GP) IIb-IIIa ligation or the generation of thromboxane (Tx) A2. Pretreatment with Syk inhibitors not only reduced SIPA and Syk phosphorylation in isolated platelets, but also diminished, up to 50%, the platelet-mediated thrombus formation when whole blood was perfused over type-III collagen. In summary, this study demonstrated that Syk is a key molecule in both SIPA and thrombus formation under flow. Pharmacological regulation of Syk may prove efficacious in treating occlusive vascular disease.
V2 vasopressin receptor deficiency causes changes in expression and function of renal and hypothalamic components involved in electrolyte and water homeostasis
Authors: Schliebe Nicole , Strotmann Rainer , Busse Kathy , Mitschke Doreen , Biebermann Heike , Schomburg Lutz , Köhrle Josef , Bär Jörg , Römpler Holger , Wess Jürgen , Schöneberg Torsten , Sangkuhl Katrin
Published: August 2008

Polyuria, hypernatremia, and hypovolemia are the major clinical signs of inherited nephrogenic diabetes insipidus (NDI). Hypernatremia is commonly considered a secondary sign caused by the net loss of water due to insufficient insertion of aquaporin-2 water channels into the apical membrane of the collecting duct cells. In the present study, we employed transcriptome-wide expression analysis to study gene expression in V2 vasopressin receptor (Avpr2)-deficient mice, an animal model for X-linked NDI. Gene expression changes in NDI mice indicate increased proximal tubular sodium reabsorption. Expression of several key genes including Na+-K+-ATPase and carbonic anhydrases was increased at the mRNA levels and accompanied by enhanced enzyme activities. In addition, altered expression was also observed for components of the eicosanoid and thyroid hormone pathways, including cyclooxygenases and deiodinases, in both kidney and hypothalamus. These effects are likely to contribute to the clinical NDI phenotype. Finally, our data highlight the involvement of the renin-angiotensin-aldosterone system in NDI pathophysiology and provide clues to explain the effectiveness of diuretics and indomethacin in the treatment of NDI.
Hemodynamic impact of mitral prosthesis-patient mismatch on pulmonary hypertension: an in silico study
Authors: Tanné David , Kadem Lyes , Rieu Régis , Pibarot Philippe
Published: August 2008

Recent clinical studies reported that prosthesis-patient mismatch (PPM) becomes clinically relevant when the effective orifice area (EOA) indexed by the body surface area (iEOA) is <1.2–1.25 cm2/m2. To examine the effect of PPM on transmitral pressure gradient and left atrial (LA) and pulmonary arterial (PA) pressures and to validate the PPM cutoff values, we used a lumped model to compute instantaneous pressures, volumes, and flows into the left-sided heart and the pulmonary and systemic circulations. We simulated hemodynamic conditions at low cardiac output, at rest, and at three levels of exercise. The iEOA was varied from 0.44 to 1.67 cm2/m2. We normalized the mean pressure gradient by the square of mean mitral flow indexed by the body surface area to determine at which cutoff values of iEOA the impact of PPM becomes hemodynamically significant. In vivo data were used to validate the numerical study, which shows that small values of iEOA (severe PPM) induce high PA pressure (residual PA hypertension) and contribute to its nonnormalization following a valve replacement, providing a justification for implementation of operative strategies to prevent PPM. Furthermore, we emphasize the major impact of pulmonary resistance and compliance on PA pressure. The model suggests also that the cutoff iEOA that should be used to define PPM at rest in the mitral position is ∼1.16 cm2/m2. At higher levels of exercise, the threshold for iEOA is rather close to 1.5 cm2/m2. Severe PPM should be considered when iEOA is <0.94 cm2/m2 at rest.
Changes in vascular and cardiac function after prolonged strenuous exercise in humans
Authors: Dawson Ellen A. , Whyte Greg P. , Black Mark A. , Jones Helen , Hopkins Nicola , Oxborough David , Gaze David , Shave Rob E. , Wilson Mat , George Keith P. , Green Daniel J.
Published: August 2008

Prolonged exercise has been shown to result in an acute depression in cardiac function. However, little is known about the effect of this type of exercise on vascular function. Therefore, the purpose of the present study was to investigate the impact of an acute bout of prolonged strenuous exercise on vascular and cardiac function and the appearance of biomarkers of cardiomyocyte damage in 15 male (32 ± 10 yr) nonelite runners. The subjects were tested on two occasions, the day before and within an hour of finishing the London marathon (229 ± 38 min). Function of the brachial and femoral arteries was determined using flow-mediated dilatation (FMD). Echocardiographic assessment of cardiac strain, strain rate, tissue velocities, and flow velocities during diastole and systole were also obtained. Venous blood samples were taken for later assessment of cardiac troponin I (cTnI), a biomarker of cardiomyocyte damage. Completion of the marathon resulted in a depression in femoral ( P = 0.04), but not brachial ( P = 0.96), artery FMD. There was no change, pre- vs. postmarathon, in vascular shear, indicating that the impaired femoral artery function was not related to hemodynamic changes. The ratio of peak early to atrial radial strain rate, a measure of left ventricular diastolic function, was reduced postmarathon ( P = 0.006). Postrace cTnI was elevated in 12 of 13 runners, with levels above the recognized clinical threshold for damage in 7 of these. In conclusion, when taken together, these data suggest a transient depression in cardiac and leg vascular function following prolonged intensive exercise.
Coupling of L-Type Ca2+Channels to KV7/KCNQ Channels Creates a Novel, Activity-Dependent, Homeostatic Intrinsic Plasticity
Authors: Wu Wendy W. , Chan C. Savio , Surmeier D. James , Disterhoft John F.
Published: August 2008

Experience-dependent modification in the electrical properties of central neurons is a form of intrinsic plasticity that occurs during development and has been observed following behavioral learning. We report a novel form of intrinsic plasticity in hippocampal CA1 pyramidal neurons mediated by the KV7/KCNQ and CaV1/L-type Ca2+channels. Enhancing Ca2+influx with a conditioning spike train (30 Hz, 3 s) potentiated the KV7/KCNQ channel function and led to a long-lasting, activity-dependent increase in spike frequency adaptation—a gradual reduction in the firing frequency in response to sustained excitation. These effects were abolished by specific blockers for CaV1/L-type Ca2+channels, KV7/KCNQ channels, and protein kinase A (PKA). Considering the widespread expression of these two channel types, the influence of Ca2+influx and subsequent activation of PKA on KV7/KCNQ channels may represent a generalized principle in fine tuning the output of central neurons that promotes stability in firing—an example of homeostatic regulation of intrinsic membrane excitability.
Evidence for a Role of Connexin 43 in Trigeminal Pain Using RNA Interference In Vivo
Authors: Ohara Peter T. , Vit Jean-Philippe , Bhargava Aditi , Jasmin Luc
Published: August 2008

The importance of glial cells in the generation and maintenance of neuropathic pain is becoming widely accepted. We examined the role of glial-specific gap junctions in nociception in the rat trigeminal ganglion in nerve-injured and -uninjured states. The connexin 43 (Cx43) gap-junction subunit was found to be confined to the satellite glial cells (SGCs) that tightly envelop primary sensory neurons in the trigeminal ganglion and we therefore used Cx43 RNA interference (RNAi) to alter gap-junction function in SGCs. Using behavioral evaluation, together with immunocytochemical and Western blot monitoring, we show that Cx43 increased in the trigeminal ganglion in rats with a chronic constriction injury (CCI) of the infraorbital nerve. Reducing Cx43 expression using RNAi in CCI rats reduced painlike behavior, whereas in non-CCI rats, reducing Cx43 expression increased painlike behavior. The degree of painlike behavior in CCI rats and intact, Cx43-silenced rats was similar. Our results support previous suggestions that increases in glial gap junctions after nerve injury increases nociceptive behavior but paradoxically the reduction of gap junctions in normal ganglia also increases nociceptive behavior, possibly a reflection of the multiple functions performed by glia.
The NF-κB Inhibitor Curcumin Blocks Sepsis-Induced Muscle Proteolysis
Authors: Poylin Vitaliy , Fareed Moin U. , O'Neal Patrick , Alamdari Nima , Reilly Natasha , Menconi Michael , Hasselgren Per-Olof
Published: August 2008

We tested the hypothesis that treatment of rats with curcumin prevents sepsis-induced muscle protein degradation. In addition, we determined the influence of curcumin on different proteolytic pathways that are activated in septic muscle (i.e., ubiquitin-proteasome-, calpain-, and cathepsin L-dependent proteolysis) and examined the role of NF-κB and p38/MAP kinase inactivation in curcumin-induced inhibition of muscle protein breakdown. Rats were made septic by cecal ligation and puncture or were sham-operated. Groups of rats were treated with three intraperitoneal doses (600 mg/kg) of curcumin or corresponding volumes of solvent. Protein breakdown rates were measured as release of tyrosine from incubated extensor digitorum longus muscles. Treatment with curcumin prevented sepsis-induced increase in muscle protein breakdown. Surprisingly, the upregulated expression of the ubiquitin ligases atrogin-1 and MuRF1 was not influenced by curcumin. When muscles from septic rats were treated with curcumin in vitro, proteasome-, calpain-, and cathepsin L-dependent protein breakdown rates were reduced, and nuclear NF-κB/p65 expression and activity as well as levels of phosphorylated (activated) p38 were decreased. Results suggest that sepsis-induced muscle proteolysis can be blocked by curcumin and that this effect may, at least in part, be caused by inhibited NF-κB and p38 activities. The results also suggest that there is not an absolute correlation between changes in muscle protein breakdown rates and changes in atrogin-1 and MuRF1 expression during treatment of muscle wasting.
Pioglitazone versus Rosiglitazone: Effects on Lipids, Lipoproteins, and Apolipoproteins in Head‐to‐Head Randomized Clinical Studies
Authors: Deeg Mark A. , Tan Meng H.
Published: August 2008

Peroxisome proliferator‐activated receptors (PPARs) play an important role in regulating both glucose and lipid metabolism. Agonists for both PPARγ and PPARγ have been used to treat dyslipidemia and hyperglycemia, respectively. In addition to affecting glucose metabolism, PPARγ agonists also regulate lipid metabolism. In this review, we will focus on the randomized clinical trials that directly compared the lipid effects of the thiazolidinedione class of PPARγ agonists, pioglitazone and rosiglitazone, head‐to‐head either as monotherapy or in combination with other lipid‐altering or glucose‐lowering agents
Photochemistry Aspects of the Laser Pyrolysis Addressing the Preparation of Oxide Semiconductor Photocatalysts
Authors: Alexandrescu R. , Morjan I. , Dumitrache F. , Scarisoreanu M. , Soare I. , Fleaca C. , Birjega R. , Popovici E. , Gavrila L. , Prodan G. , Ciupina V. , Filoti G. , Kuncser V. , Vekas L.
Published: August 2008

The laser pyrolysis is a powerful and a versatile tool for the gas‐phase synthesis of nanoparticles. In this paper, some fundamental and applicative characteristics of this technique are outlined and recent results obtained in the preparation of gamma iron oxide (γ‐Fe2O3) and titania (TiO2) semiconductor nanostructures are illustrated.
Nanosized iron oxide particles (4 to 9 nm diameter values)
have been directly synthesized by the laser‐induced pyrolysis of a
mixture containing iron pentacarbonyl/air (as oxidizer)/ethylene
(as sensitizer). Temperature‐dependent Mossbauer spectroscopy
shows that mainly maghemite is present in the sample obtained at
higher laser power. The use of selected Fe2O3 samples for the preparation of water‐dispersed magnetic nanofluids is also discussed. TiO2 nanoparticles comprising a mixture of anatase and rutile phases were synthesized via the laser pyrolysis of TiCl4‐ (vapors) based gas‐phase mixtures. High precursor concentration of the oxidizer was found to favor the prevalent anatase phase (about 90%) in the titania nanopowders.
Acceptance Threshold: A Bidimensional Research Method for User-Oriented Quality Evaluation Studies
Authors: Jumisko-Pyykkö S. , Malamal Vadakital V. K. , Hannuksela M. M.
Published: August 2008

Subjective quality evaluation is widely used to optimize system performance as a part of end-products. It is often desirable to know whether a certain system performance is acceptable, that is, whether the system reaches the minimum level to satisfy user expectations and needs. The goal of this paper is to examine research methods for assessing overall acceptance of quality in subjective quality evaluation methods. We conducted three experiments to develop our methodology and test its validity under heterogeneous stimuli in the context of mobile television. The first experiment examined the possibilities of using a simplified continuous assessment method for assessing overall acceptability. The second experiment explored the boundary between acceptable and unacceptable quality when the stimuli had clearly detectable differences. The third experiment compared the perceived quality impacts of small differences between the stimuli close to the threshold of acceptability. On the basis of our results, we recommend using a bidimensional retrospective measure combining acceptance and satisfaction in consumer-/user-oriented quality evaluation experiments.
On the Existence of Bright Solitons in Cubic‐Quintic Nonlinear Schrödinger Equation with Inhomogeneous Nonlinearity
Authors: Belmonte-Beitia Juan
Published: August 2008

We give a proof of the existence of stationary bright soliton solutions of the cubic‐quintic nonlinear Schrödinger equation with inhomogeneous nonlinearity. By
using bifurcation theory, we prove that the norm of the positive solution goes to
zero as the parameter λ, called chemical potential in the Bose‐Einstein
condensates′ literature, tends to zero. Moreover, we solve the time‐dependent cubic‐quintic
nonlinear Schrödinger equation with inhomogeneous nonlinearities by using
a numerical method.
A Sociology of Scandal and Moral Transgression
Authors: Jacobsson Kerstin , Löfmarck Erik
Published: August 2008

In this article, we use the case of a government scandal in Sweden to develop a theoretical perspective by which to understand the moral nature of political scandals. We draw on insights from Durkheim's sociology of morality and point, inter alia, to the ritual character of scandals. However, in contrast to most Durkheimian readings, the perspective presented does not presume the existence of a moral consensus. The scandal is understood as a confrontation between various systems of norms. Rather than confirming a given moral order, scandals provoke moral positioning and help in clarifying — and dramatizing — lines of difference or conflict. The empirical case studied is a government scandal in Sweden in 2006 (Nannygate) that forced two government ministers to resign after less than 10 days in office when it was revealed that they had not paid their TV licence and, moreover, had bought `black' (untaxed) services. This transgression provoked a massive public reaction at the time.
Many-Voiced or Unisono?
Authors: Roose Henk
Published: August 2008

In this article, I analyse empirically whether the audience attending classical concerts can be subdivided into three segments — following the lead of Howard Becker's Art Worlds (1984). Moreover, I investigate how far these groups have different aesthetic dispositions towards classical music. Based on an extensive audience survey in five institutions staging both symphonic and chamber music in Flanders, Belgium (2005), three groups are distinguished based on the frequency of attendance: the passers-by, the interested participants and the inner circle. It is found that these segments differ in socio-demographic composition, have different motives for attendance and have different aesthetic dispositions towards classical music. Yet, all segments share the wish to be emotionally moved and affected by music. Implications for cultural policy and marketing the arts are discussed.
Left Ventricular Pseudoaneurysm With Infective Pericarditis: A Rare Cause of Intractable Hemoptysis
Authors: Vijayvergiya Rajesh , Dhanaraj Singh Chongtham  , Shyam Kumar Thingnam  , Grover Anil , Lal Anupam
Published: August 2008

A 52-year-old man with diabetes presented with recurrent, massive hemoptysis following pericardiectomy for pyopericardium secondary to Streptococcus viridans infection. Chest radiograph and bronchoscopic examinations revealed no bronchial cause. Computed tomography of the chest and echocardiography showed a pseudoaneurysm of the left ventricle. Surgical exploration confirmed that the pseudoaneurysm communicated with the left lung parenchyma and was the cause of recurrent intractable hemoptysis.
Training Directors' Conceptualizations of the Intersections of Diversity and Trainee Competence Problems
Authors: Shen Miller David S. , Forrest Linda , Elman Nancy S.
Published: August 2008

Counseling psychology has demonstrated leadership on multicultural issues through serious and committed attention to diversity in scholarship, conferences, and training and recruitment. Yet a survey of the literature on trainees with competence problems resulted in limited references to race/ethnicity and/or gender (REG). Using transcripts of phone interviews, we examined the degree to which Training Directors from 14 counseling psychology doctoral programs included REG in their conceptualizations of trainee remediation. REG conceptualizations differed in terms of (a) definitional clarity and conceptual sophistication about RE, (b) differential integration of approaches to diversity and remediation, and (c) strong emotions associated with race/ethnicity in trainee remediation. Implications for training and research are discussed.