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1

High rates of pregnancy loss by subordinates leads to high reproductive skew in wild golden lion tamarins (Leontopithecus rosalia)  

E-print Network

Ã?Ã? Ã? Ã?Ã?Ã? Ã? Ã?Ã? High rates of pregnancy loss by subordinates leads to high reproductive skew in wild., French, Jeffrey A., Dietz, James M., High rates of pregnancy loss by subordinates leads to high ACCEPTED MANUSCRIPT TITLE High rates of pregnancy loss by subordinates leads to high reproductive skew

French, Jeffrey A.

2

High rates of pregnancy loss by subordinates leads to high reproductive skew in wild golden lion tamarins (Leontopithecus rosalia).  

PubMed

Across taxa, cooperative breeding has been associated with high reproductive skew. Cooperatively breeding golden lion tamarins (Leontopithecus rosalia) were long thought to have a monogynous mating system in which reproduction was limited to a single dominant female. Subordinates with few reproductive opportunities delayed dispersal and remained in the natal group to provide alloparental care to siblings, thus allowing dominant reproductive females to meet the energetic needs associated with high rates of reproduction and successful infant rearing. The goal of this study was to re-assess monogyny in wild golden lion tamarin groups based upon pregnancy diagnoses that used non-invasive enzyme immunoassay for progesterone and cortisol, combined with weekly data on individual weight gain, bi-annual physical examinations noting pregnancy and lactation status and daily behavioral observations. We established quantitative and qualitative criteria to detect and determine the timing of pregnancies that did not result in the birth of infants. Pregnancy polygyny occurred in 83% of golden lion tamarin groups studied. The loss of 64% of subordinate pregnancies compared to only 15% by dominant females limited reproductive success mainly to dominant females, thus maintaining high reproductive skew in female golden lion tamarins. Pregnancy loss by subordinate adults did not appear to result from dominant interference in subordinate hormonal mechanisms, but more likely resulted from subordinate abandonment of newborn infants to mitigate dominant aggression. PMID:23454002

Henry, MaLinda D; Hankerson, Sarah J; Siani, Jennifer M; French, Jeffrey A; Dietz, James M

2013-05-01

3

High rates of pregnancy loss by subordinates leads to high reproductive skew in wild golden lion tamarins (Leontopithecus rosalia)  

PubMed Central

Across taxa, cooperative breeding has been associated with high reproductive skew. Cooperatively breeding golden lion tamarins (Leontopithecus rosalia) were long thought to have a monogynous mating system in which reproduction was limited to a single dominant female. Subordinates with few reproductive opportunities delayed dispersal and remained in the natal group to provide alloparental care to siblings, thus allowing dominant reproductive females to meet the energetic needs associated with high rates of reproduction and successful infant rearing. The goal of this study was to re-assess monogyny in wild golden lion tamarin groups based upon pregnancy diagnoses that used non-invasive enzyme immunoassay for progesterone and cortisol, combined with weekly data on individual weight gain, bi-annual physical examinations noting pregnancy and lactation status and daily behavioral observations. We established quantitative and qualitative criteria to detect and determine the timing of pregnancies that did not result in the birth of infants. Pregnancy polygyny occurred in 83% of golden lion tamarin groups studied. The loss of 64% of subordinate pregnancies compared to only 15% by dominant females limited reproductive success mainly to dominant females, thus maintaining high reproductive skew in female golden lion tamarins. Pregnancy loss by subordinate adults did not appear to result from dominant interference in subordinate hormonal mechanisms, but more likely resulted from subordinate abandonment of newborn infants to mitigate dominant aggression. PMID:23454002

Henry, MaLinda D.; Hankerson, Sarah J.; Siani, Jennifer M.; French, Jeffrey A.; Dietz, James M.

2013-01-01

4

Variation in the reproductive rate of bats  

Microsoft Academic Search

In many respects, bats have relatively slow life histories. However, the reproductive rate of bats (i.e., the proportion of females that reproduce in any breeding season) has not been critically examined. We compiled data on the reproductive rates of bats to test predictions based on life-history theory. Among 257 samples from 103 species, re - productive rate varied considerably and

Robert M. R. Barclay; Joel Ulmer; Cameron J. A. MacKenzie; Megan S. Thompson; Leif Olson; Julianne McCool; Elvie Cropley; Graeme Poll

2004-01-01

5

Management of Replacement Heifers for a High Reproductive and Calving Rate.  

E-print Network

heifers show estrus between 13 and 16 months of age if they are of sufficient size and weight. Exceptions to this include Brahman heif ers, Brahman crossbred heifers and heifers from some breeds derived from crosses with Brahman . Approximately 90... separated for special care at calving and through the breeding season. ? Grow heifers at a rate of 1 to 1 V2 pounds per day - have them in moderate to good body condition at calving time . Management - at calving ? Move early-bred heifers into easily...

Beverly, John R.; Spitzer, John C.

1980-01-01

6

INTAKE RATES AND THE TIMING OF CROSSBILL REPRODUCTION  

Microsoft Academic Search

I measured the foraging rates of breeding and nonbreeding populations of White-winged Crossbills (Loxia leucoptera) and Red Crossbills (L. curvirostra) throughout the year in the northeastern United States and adjacent Canada. I compared actual food intake rates (80 samples from 26 populations) to those predicted for five hypotheses that pertain to the timing of reproduction. To form eggs, crossbills required

CRAIG W. BENKMAN

7

Reproductive rate, not dominance status, affects fecal glucocorticoid levels in breeding female meerkats.  

PubMed

Glucocorticoid hormones (GCs) have been studied intensively to understand the associations between physiological stress and reproductive skew in animal societies. However, we have little appreciation of the range of either natural levels within and among individuals, or the associations among dominance status, reproductive rate and GCs levels during breeding. To address these shortcomings, we examined variation in fecal glucocorticoid metabolites (fGC) during breeding periods in free-ranging female meerkats (Suricata suricatta) over 11 years. The vast majority of variation in fGC levels was found within breeding events by the same female (~87%), with the remaining variation arising among breeding events and among females. Concentrations of fGC generally tripled as pregnancy progressed. However, females with a high reproductive rate, defined as those conceiving within a month following parturition (mean = 9 days postpartum), showed significant reductions in fGC in the final 2 weeks before parturition. Despite these reductions, females with a high reproductive rate had higher fGC levels at conception of the following litter than those breeding at a low rate. After controlling for the higher reproductive rate of dominants, we found no association between levels of fGC and either age or dominance status. Our results suggest that one should be cautious about interpreting associations between dominance status, reproductive skew and GCs levels, without knowledge of the natural variation in GCs levels within and among females. PMID:22210199

Barrette, Marie-France; Monfort, Steven L; Festa-Bianchet, Marco; Clutton-Brock, Tim H; Russell, Andrew F

2012-04-01

8

Variation in Rates of Asexual Reproduction By Convolutriloba retrogemma  

Microsoft Academic Search

Convolutriloba retrogemma, an acoel turbellarian (phylum Platyhelminthes), engages in an obligate symbiotic relationship with unicellular algae, This species reproduces asexually by budding from the posterior end of the parent individual. The rate of reproduction of 24 newly budded flatworms of various sizes was studied over a period of six weeks, Flatworms were individually placed into 6 mL of 0.2 ?m

Rahim Sara

2003-01-01

9

Exploring individual quality: Basal metabolic rate and reproductive performance in storm-petrels  

USGS Publications Warehouse

Despite evidence that some individuals achieve both superior reproductive performance and high survivorship, the factors underlying variation in individual quality are not well understood. The compensation and increased-intake hypotheses predict that basal metabolic rate (BMR) influences reproductive performance; if so, variation in BMR may be related to differences in individual quality. We evaluated whether BMR measured during the incubation period provides a proximate explanation for variation in individual quality by measuring the BMRs and reproductive performance of Leach's storm-petrels (Oceanodroma leucorhoa) breeding on Kent Island, New Brunswick, Canada, during 2000 and 2001. We statistically controlled for internal (body mass, breeding age, sex) and external (year, date, time of day) effects on BMR. We found that males with relatively low BMRs hatched their eggs earlier in the season and that their chicks' wing growth rates were faster compared to males with relatively high BMRs. Conversely, BMR was not related to egg volume, hatching date, or chick growth rate for females or to lifetime (???23 years) hatching success for either sex. Thus, for males but not for females, our results support the compensation hypothesis. This hypothesis predicts that animals with low BMRs will achieve better reproductive performance than animals with high BMRs because they have lower self-maintenance costs and therefore can apportion more energy to reproduction. These results provide evidence that intraspecific variation in reproductive performance is related to BMR and suggest that BMR may influence individual quality in males. ?? The Author 2005. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved.

Blackmer, A.L.; Mauck, R.A.; Ackerman, J.T.; Huntington, C.E.; Nevitt, G.A.; Williams, J.B.

2005-01-01

10

The dynamics of sexual conflict over mating rate with endosymbiont infection that affects reproductive phenotypes  

E-print Network

; reproductive traits; sexual selection; Wolbachia. Abstract Maternally inherited endosymbionts have been' in sexual conflict, thus suggesting the novel hypothesis that endosymbiont-induced changes in reproductiveThe dynamics of sexual conflict over mating rate with endosymbiont infection that affects

Gavrilets, Sergey

11

Individual variation in reproductive costs of reproduction: high-quality females always do better.  

PubMed

1. Although life-history theory predicts substantial costs of reproduction, individuals often show positive correlations among life-history traits, rather than trade-offs. The apparent absence of reproductive costs may result from heterogeneity in individual quality. 2. Using detailed longitudinal data from three contrasted ungulate populations (mountain goats, Oreamnos americanus; bighorn sheep, Ovis canadensis; and roe deer, Capreolus capreolus), we assessed how individual quality affects the probability of detecting a cost of current reproduction on future reproduction for females. We used a composite measure of individual quality based on variations in longevity (all species), success in the last breeding opportunity before death (goats and sheep), adult mass (all species), and social rank (goats only). 3. In all species, high-quality females consistently had a higher probability of reproduction, irrespective of previous reproductive status. In mountain goats, we detected a cost of reproduction only after accounting for differences in individual quality. Only low-quality female goats were less likely to reproduce following years of breeding than of nonbreeding. Offspring survival was lower in bighorn ewes following years of successful breeding than after years when no lamb was produced, but only for low-quality females, suggesting that a cost of reproduction only occurred for low-quality females. 4. Because costs of reproduction differ among females, studies of life-history evolution must account for heterogeneity in individual quality. PMID:18700872

Hamel, Sandra; Côté, Steeve D; Gaillard, Jean-Michel; Festa-Bianchet, Marco

2009-01-01

12

Low Reproductive Rates of Lake Superior Bald Eagles: Low Food Delivery Rates or Environmental Contaminants?  

Microsoft Academic Search

Reproductive rate (productivity) of bald eagles (Haliaeetus leucocephalus) nesting on the shores of Lake Superior was significantly less than that of neighboring eagles nesting in inland Wisconsin (1.0 vs. 1.3 young per breeding attempt, 1989–1993), and at other inland lake\\/riverine habitats in the Great Lakes Basin. It is possible that the current causes of low productivity on Lake Superior might

Cheryl R. Dykstra; Michael W. Meyer; D. Keith Warnke; William H. Karasov; David E. Andersen; William W. Bowerman IV; John P. Giesy

1998-01-01

13

Macroevolutionary speciation rates are decoupled from the evolution of intrinsic reproductive isolation in Drosophila and birds  

PubMed Central

The rate at which speciation occurs varies greatly among different kinds of organisms and is frequently assumed to result from species- or clade-specific factors that influence the rate at which populations acquire reproductive isolation. This premise leads to a fundamental prediction that has never been tested: Organisms that quickly evolve prezygotic or postzygotic reproductive isolation should have faster rates of speciation than organisms that slowly acquire reproductive isolation. We combined phylogenetic estimates of speciation rates from Drosophila and birds with a method for analyzing interspecific hybridization data to test whether the rate at which individual lineages evolve reproductive isolation predicts their macroevolutionary rate of species formation. We find that some lineages evolve reproductive isolation much more quickly than others, but this variation is decoupled from rates of speciation as measured on phylogenetic trees. For the clades examined here, reproductive isolation—especially intrinsic, postzygotic isolation—does not seem to be the rate-limiting control on macroevolutionary diversification dynamics. These results suggest that factors associated with intrinsic reproductive isolation may have less to do with the tremendous variation in species diversity across the evolutionary tree of life than is generally assumed. PMID:24003144

Rabosky, Daniel L.; Matute, Daniel R.

2013-01-01

14

Conception rates following assisted reproduction in poor responder patients: a retrospective study in 300 consecutive cycles  

Microsoft Academic Search

Poor response to ovarian stimulation for assisted reproduction treatment is a therapeutic challenge. Oocyte donation may be unacceptable to some patients, and many couples opt to continue with treatment despite low follicle numbers. Minimal data are available regarding conception rates in poor responders who elect to undergo oocyte retrieval. This study summarizes the outcome of assisted reproduction treatment in poor

Ulun Ulug; Izhar Ben-Shlomo; Ersadik Turan; Halit Firat Erden; Mehmet Ali Akman; Mustafa Bahceci

2003-01-01

15

Individual heterogeneity in reproductive rates and cost of reproduction in a long-lived vertebrate  

PubMed Central

Individual variation in reproductive success is a key feature of evolution, but also has important implications for predicting population responses to variable environments. Although such individual variation in reproductive outcomes has been reported in numerous studies, most analyses to date have not considered whether these realized differences were due to latent individual heterogeneity in reproduction or merely random chance causing different outcomes among like individuals. Furthermore, latent heterogeneity in fitness components might be expressed differently in contrasted environmental conditions, an issue that has only rarely been investigated. Here, we assessed (i) the potential existence of latent individual heterogeneity and (ii) the nature of its expression (fixed vs. variable) in a population of female Weddell seals (Leptonychotes weddellii), using a hierarchical modeling approach on a 30-year mark–recapture data set consisting of 954 individual encounter histories. We found strong support for the existence of latent individual heterogeneity in the population, with “robust” individuals expected to produce twice as many pups as “frail” individuals. Moreover, the expression of individual heterogeneity appeared consistent, with only mild evidence that it might be amplified when environmental conditions are severe. Finally, the explicit modeling of individual heterogeneity allowed us to detect a substantial cost of reproduction that was not evidenced when the heterogeneity was ignored. PMID:23919151

Chambert, Thierry; Rotella, Jay J; Higgs, Megan D; Garrott, Robert A

2013-01-01

16

Generation time, net reproductive rate, and growth in stage-age-structured populations.  

PubMed

Major insights into the relationship between life-history features and fitness have come from Lotka's proof that population growth rate is determined by the level (expected amount) of reproduction and the average timing of reproduction of an individual. But this classical result is limited to age-structured populations. Here we generalize this result to populations structured by stage and age by providing a new, unique measure of reproductive timing (Tc) that, along with net reproductive rate (R0), has a direct mathematical relationship to and approximates growth rate (r). We use simple examples to show how reproductive timing Tc and level R0 are shaped by stage dynamics (individual trait changes), selection on the trait, and parent-offspring phenotypic correlation. We also show how population structure can affect dispersion in reproduction among ages and stages. These macroscopic features of the life history determine population growth rate r and reveal a complex interplay of trait dynamics, timing, and level of reproduction. Our results contribute to a new framework of population and evolutionary dynamics in stage-and-age-structured populations. PMID:24823821

Steiner, Ulrich K; Tuljapurkar, Shripad; Coulson, Tim

2014-06-01

17

Vienna Yearbook of Population Research 2009, pp. 197-215 The net reproduction rate and the type-  

E-print Network

Vienna Yearbook of Population Research 2009, pp. 197-215 The net reproduction rate and the type- reproduction number in multiregional demography Hisashi Inaba* Abstract In order to study effects of migration of the 1970s, its key concept, the multiregional net reproduction rate, has been long neglected

Inaba, Hisashi

18

Senescence rates and late adulthood reproductive success are strongly influenced by personality in a long-lived seabird.  

PubMed

Studies are increasingly demonstrating that individuals differ in their rate of ageing, and this is postulated to emerge from a trade-off between current and future reproduction. Recent theory predicts a correlation between individual personality and life-history strategy, and from this comes the prediction that personality may predict the intensity of senescence. Here we show that boldness correlates with reproductive success and foraging behaviour in wandering albatrosses, with strong sex-specific differences. Shy males show a strong decline in reproductive performance with age, and bold females have lower reproductive success in later adulthood. In both sexes, bolder birds have longer foraging trips and gain more mass per trip as they get older. However, the benefit of this behaviour appears to differ between the sexes, such that it is only matched by high reproductive success in males. Together our results suggest that personality linked foraging adaptations with age are strongly sex-specific in their fitness benefits and that the impact of boldness on senescence is linked to ecological parameters. PMID:25473008

Patrick, Samantha C; Weimerskirch, Henri

2015-01-22

19

High repetition rate fiber lasers  

E-print Network

This thesis reports work in high repetition rate femtosecond fiber lasers. Driven by the applications including optical arbitrary waveform generation, high speed optical sampling, frequency metrology, and timing and frequency ...

Chen, Jian, Ph. D. Massachusetts Institute of Technology

2009-01-01

20

Pollen flow and effects of population structure on selfing rates and female and male reproductive success in fragmented Magnolia stellata populations  

PubMed Central

Background Fragmentation of plant populations may affect mating patterns and female and male reproductive success. To improve understanding of fragmentation effects on plant reproduction, we investigated the pollen flow patterns in six adjacent local populations of Magnolia stellata, an insect-pollinated, threatened tree species in Japan, and assessed effects of maternal plant (genet) size, local genet density, population size and neighboring population size on female reproductive success (seed production rates), and effects of mating distance, paternal genet size, population size and separation of populations on male reproductive success. Results The seed production rate, i.e. the proportion of ovules that successfully turned into seeds, varied between 1.0 and 6.5%, and increased with increasing population size and neighboring population size, and with decreasing maternal genet size and local genet density. The selfing rate varied between 3.6 and 28.9%, and increased with increasing maternal genet size and with declining local genet density. Male reproductive success increased with increasing paternal genet size, and decreased with increasing mating distance and separation of population. Pollen flow between the populations was low (6.1%) and highly leptocurtic. Conclusions Our results indicate that habitat fragmentation, separation and reduced size of populations, affected mating patterns and reproductive success of M. stellata. Local competition for pollinators and plant display size were likely to alter the reproductive success. PMID:23517612

2013-01-01

21

Comparison of Gene Repertoires and Patterns of Evolutionary Rates in Eight Aphid Species That Differ by Reproductive Mode  

PubMed Central

In theory, the loss of sexual reproduction is expected to result in the accumulation of deleterious mutations. In aphids, two main types of life cycle, cyclic and obligate parthenogenesis, represent respectively “sexual” and “asexual” reproductive modes. We used the complete pea aphid genome and previously published expressed sequence tags (ESTs) from two other aphid species. In addition, we obtained 100,000 new ESTs from five more species. The final set comprised four sexual and four asexual aphid species and served to test the influence of the reproductive mode on the evolutionary rates of genes. We reconstructed coding sequences from ESTs and annotated these genes, discovering a novel peptide gene family that appears to be among the most highly expressed transcripts from several aphid species. From 203 genes found to be 1:1 orthologs among the eight species considered, we established a species tree that partly conflicted with taxonomy (for Myzus ascalonicus). We then used this topology to evaluate the dynamics of evolutionary rates and mutation accumulation in the four sexual and four asexual taxa. No significant increase of the nonsynonymous to synonymous ratio or of nonsynonymous mutation numbers was found in any of the four branches for asexual taxa. We however found a significant increase of the synonymous rate in the branch leading to the asexual species Rhopalosiphum maidis, which could be due to a change in the mutation rate or to an increased number of generations implied by its change of life cycle. PMID:22215803

Ollivier, M.; Gabaldón, T.; Poulain, J.; Gavory, F.; Leterme, N.; Gauthier, J.-P.; Legeai, F.; Tagu, D.; Simon, J. C.; Rispe, C.

2012-01-01

22

TROPHIC STRUCTURE, REPRODUCTIVE SUCCESS, AND GROWTH RATE OF FISHES IN A NATURAL AND MODIFIED HEADWATER STREAM  

EPA Science Inventory

The impact of removing riparian vegetation, channel straightening, and fluctuations in flow regime on trophic structure, reproductive success, and growth rate of fishes was assessed in a natural (Jordan Creek(JC)) and modified (Big Ditch(BD)) headwater stream in eastcentral Illin...

23

Dependence of Reproduction Rate on Pressure as a Hallmark of Deep-Sea Bacteria  

PubMed Central

Strains of bacteria in axenic culture were isolated from samples of depths between 1,957 and 10,476 m of the Pacific Ocean. All of the bacteria from this range of depths were barophilic. The pressure at which the rate of reproduction was maximal was found to be correlated with the depth of origin of the isolates. PMID:16346153

Yayanos, A. Aristides; Dietz, Allan S.; Van Boxtel, R.

1982-01-01

24

Strain-rate effects for high-strain-rate computations  

Microsoft Academic Search

This paper examines the effect of strain rates for computations involving high strain-rates, beyond 103 s - 1. Although it is generally agreed that there is an enhanced rate effect at these higher rates, there is uncertainty regarding the interpretation of dynamic test data, the form of the high-rate effect, and the effect of the high rates on practical problems

G. R. Johnson; T. J. Holmquist; C. E. Anderson Jr.; A. E. Nicholls

2006-01-01

25

Human Disturbance Influences Reproductive Success and Growth Rate in California Sea Lions (Zalophus californianus)  

PubMed Central

The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups) for California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources). Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations. PMID:21436887

French, Susannah S.; González-Suárez, Manuela; Young, Julie K.; Durham, Susan; Gerber, Leah R.

2011-01-01

26

Cyclic variations in nitrogen uptake rate in soybean plants: uptake during reproductive growth  

NASA Technical Reports Server (NTRS)

Net uptake of NO3- by non-nodulated soybean plants [Glycine max (L.) Merr. cv. Ransom] growing in flowing hydroponic culture was measured daily during a 63 d period of reproductive development between the first florally inductive photoperiod and [unknown word] seed growth. Removal of NO3- from a replenished solution containing 1.0 mol m-3 NO3- was determined by ion chromatography. Uptake of NO3- continued throughout reproductive development. The net uptake rate of NO3- cycled between maxima and minima with a periodicity of oscillation of 3 to 7 d during the floral stage and about 6 d during the fruiting stage. Coupled with increasing concentrations of carbon and C : N ratios in tissues, the oscillations in net uptake rates of NO3- are evidence that the demand for carbohydrate by reproductive organs is contingent on the availability of nitrogen in the shoot pool rather than that the demand for nitrogen follows the flux of carbohydrate into reproductive tissues.

Vessey, J. K.; Raper, C. D. Jr; Henry, L. T.; Raper CD, J. r. (Principal Investigator)

1990-01-01

27

High Data Rate Instrument Study  

NASA Technical Reports Server (NTRS)

The High Data Rate Instrument Study was a joint effort between the Jet Propulsion Laboratory (JPL) and the Goddard Space Flight Center (GSFC). The objectives were to assess the characteristics of future high data rate Earth observing science instruments and then to assess the feasibility of developing data processing systems and communications systems required to meet those data rates. Instruments and technology were assessed for technology readiness dates of 2000, 2003, and 2006. The highest data rate instruments are hyperspectral and synthetic aperture radar instruments which are capable of generating 3.2 Gigabits per second (Gbps) and 1.3 Gbps, respectively, with a technology readiness date of 2003. These instruments would require storage of 16.2 Terebits (Tb) of information (RF communications case of two orbits of data) or 40.5 Tb of information (optical communications case of five orbits of data) with a technology readiness date of 2003. Onboard storage capability in 2003 is estimated at 4 Tb; therefore, all the data created cannot be stored without processing or compression. Of the 4 Tb of stored data, RF communications can only send about one third of the data to the ground, while optical communications is estimated at 6.4 Tb across all three technology readiness dates of 2000, 2003, and 2006 which were used in the study. The study includes analysis of the onboard processing and communications technologies at these three dates and potential systems to meet the high data rate requirements. In the 2003 case, 7.8% of the data can be stored and downlinked by RF communications while 10% of the data can be stored and downlinked with optical communications. The study conclusion is that only 1 to 10% of the data generated by high data rate instruments will be sent to the ground from now through 2006 unless revolutionary changes in spacecraft design and operations such as intelligent data extraction are developed.

Schober, Wayne; Lansing, Faiza; Wilson, Keith; Webb, Evan

1999-01-01

28

Influence of acupuncture on the pregnancy rate in patients who undergo assisted reproduction therapy  

Microsoft Academic Search

Objective: To evaluate the effect of acupuncture on the pregnancy rate in assisted reproduction therapy (ART) by comparing a group of patients receiving acupuncture treatment shortly before and after embryo transfer with a control group receiving no acupuncture.Design: Prospective randomized study.Setting: Fertility center.Patient(s): After giving informed consent, 160 patients who were undergoing ART and who had good quality embryos were

Wolfgang E. Paulus; Mingmin Zhang; Erwin Strehler; Imam El-Danasouri; Karl Sterzik

2002-01-01

29

Cumulative pregnancy and live birth rates in women with antiphospholipid antibodies undergoing assisted reproduction  

Microsoft Academic Search

3To whom correspondence should be addressed The aims of this study were to investigate the influence of antiphospholipid antibodies (APA) on cumulative preg- nancy and live-birth rates in patients undergoing assisted reproductive treatment. Serum samples from 173 patients were collected prior to initiation treatment cycle and tested by enzyme-linked immunosorbent assay (ELISA) for the presence of immunoglobulin (Ig)G, IgM and

T. Eldar-Geva; C. Wood; N. Lolatgis; L. Rombauts; G. Kovacs; J. Fuscaldo; A. O. Trounson

1999-01-01

30

Divergent selection on, but no genetic conflict over, female and male timing and rate of reproduction in a human population  

PubMed Central

The sexes often have different phenotypic optima for important life-history traits, and because of a largely shared genome this can lead to a conflict over trait expression. In mammals, the obligate costs of reproduction are higher for females, making reproductive timing and rate especially liable to conflict between the sexes. While studies from wild vertebrates support such sexual conflict, it remains unexplored in humans. We used a pedigreed human population from preindustrial Finland to estimate sexual conflict over age at first and last reproduction, reproductive lifespan and reproductive rate. We found that the phenotypic selection gradients differed between the sexes. We next established significant heritabilities in both sexes for all traits. All traits, except reproductive rate, showed strongly positive intersexual genetic correlations and were strongly genetically correlated with fitness in both sexes. Moreover, the genetic correlations with fitness were almost identical in men and women. For reproductive rate, the intersexual correlation and the correlation with fitness were weaker but again similar between the sexes. Thus, in this population, an apparent sexual conflict at the phenotypic level did not reflect an underlying genetic conflict over the studied reproductive traits. These findings emphasize the need for incorporating genetic perspectives into studies of human life-history evolution. PMID:24107531

Bolund, Elisabeth; Bouwhuis, Sandra; Pettay, Jenni E.; Lummaa, Virpi

2013-01-01

31

Reproductive ecology of tree swallows (Tachycineta bicolor) with high levels of polychlorinated biphenyl contamination  

SciTech Connect

Tree swallows(Tachycineta bicolor) breeding along the Hudson River forage extensively on PCB-contaminated insects that emerge from the river. The authors studied the reproductive ecology and behavior of tree swallows breeding at several sites along the Hudson River. Related work has shown that PCB levels in both eggs and chicks were among the highest ever reported in this species, with concentrations comparable to those found in aquatic organisms in the Hudson River. In 1994, reproductive success at PCB-contaminated sites was significantly impaired relative to other sites in New York. Reduced reproductive success was largely due to high levels of nest abandonment during incubation and reduced hatchability of eggs. In 1995, reproductive output was normal, but higher than expected rates of abandonment and supernormal clutches persisted. Growth and development of nestlings was not significantly impaired. Given the levels of contamination in this population, the success of most Hudson River tree swallows reinforces the importance of understanding interspecific differences in the effects of contaminants.

McCarty, J.P.; Secord, A.L.

1999-07-01

32

Individual variation in reproductive costs of reproduction: high-quality females always do better  

Microsoft Academic Search

Summary 1. Although life-history theory predicts substantial costs of reproduction, individuals often show positive correlations among life-history traits, rather than trade-offs. The apparent absence of reproductive costs may result from heterogeneity in individual quality. 2. Using detailed longitudinal data from three contrasted ungulate populations (mountain goats, Oreamnos americanus ; bighorn sheep, Ovis canadensis ; and roe deer, Capreolus capreolus ),

Sandra Hamel; Steeve D. Côté; Jean-Michel Gaillard; Marco Festa-Bianchet

2009-01-01

33

Evidence for harvest-induced maternal influences on the reproductive rates of fish populations  

PubMed Central

Knowledge of the relationship between the number of offspring produced (recruitment) and adult abundance is fundamental to forecasting the dynamics of an exploited population. Although small-scale experiments have documented the importance of maternal quality to offspring survival in plants and animals, the effects of this association on the recruitment dynamics of exploited populations are largely unknown. Here, we present results from both a simple population model and a meta-analysis of time-series data from 25 species of exploited marine fishes that suggest that a population of older, larger individuals has a higher maximum reproductive rate than an equivalent population of younger, smaller individuals, and that this difference increases with the reproductive lifespan of the population. These findings (i) establish an empirical link between population age structure and reproductive rate that is consistent with strong effects of maternal quality on population dynamics and (ii) provide further evidence that extended age structure is essential to the sustainability of many exploited fish stocks. PMID:19033140

Venturelli, Paul A.; Shuter, Brian J.; Murphy, Cheryl A.

2008-01-01

34

Bite rates in Rocky Mountain bighorn sheep ( Ovis canadensis ): effects of season, age, sex and reproductive status  

Microsoft Academic Search

We investigated the effects of vegetation biomass, crude protein content of consumed forage, age, sex and reproductive status on bite rates in Rocky Mountain bighorn sheep. We expected higher bite rates and vigilance in lactating females with young and higher bite rates in young growing individuals, than in non-reproducing females or rams. Lactating ewes had higher bite rates than yeld

K. E. Ruckstuhl; M. Festa-Bianchet; J. T. Jorgenson

2003-01-01

35

A new method for calculating net reproductive rate from graph reduction with applications to the control of invasive species  

Microsoft Academic Search

Matrix models are widely used for demographic analysis of age and stage\\u000a structured biological populations. Dynamic properties of the model can\\u000a be summarized by the net reproductive rate R (0). In this paper, we\\u000a introduce a new method to calculate and analyze the net reproductive\\u000a rate directly from the life cycle graph of the matrix. We show, with\\u000a examples, how

T. de-Camino-Beck; M. A. Lewis

2007-01-01

36

Growth and Reproductive Rates in Two Populations of Spinner Dolphins, Stenella longivostvis, with Different Histories of Exploitation1  

Microsoft Academic Search

A model of density-dependent change in net reproductive rate (births minus deaths) has been used in assessing status of dolphin stocks in the eastern tropical Pacific. The eastern spinner population has been estimated to be at a lower fraction of original size (17-25%) than is the population of whitebelly spinners (58-72%). Higher reproductive rates would be expected in the former

W. F. PERRIN; J. R. HENDERSON

37

Epidemic growth rate and household reproduction number in communities of households, schools and workplaces  

PubMed Central

In this paper we present a novel and coherent modelling framework for the characterisation of the real-time growth rate in SIR models of epidemic spread in populations with social structures of increasing complexity. Known results about homogeneous mixing and multitype models are included in the framework, which is then extended to models with households and models with households and schools/workplaces. Efficient methods for the exact computation of the real-time growth rate are presented for the standard SIR model with constant infection and recovery rates (Markovian case). Approximate methods are described for a large class of models with time-varying infection rates (non-Markovian case). The quality of the approximation is assessed via comparison with results from individual-based stochastic simulations. The methodology is then applied to the case of influenza in models with households and schools/workplaces, to provide an estimate of a household-to-household reproduction number and thus asses the effort required to prevent an outbreak by targeting control policies at the level of households. The results highlight the risk of underestimating such effort when the additional presence of schools/workplaces is neglected. Our framework increases the applicability of models of epidemic spread in socially structured population by linking earlier theoretical results, mainly focused on time-independent key epidemiological parameters (e.g. reproduction numbers, critical vaccination coverage, epidemic final size) to new results on the epidemic dynamics. PMID:21120484

Pellis, Lorenzo; Ferguson, Neil M.; Fraser, Christophe

2013-01-01

38

High Resolution, High Frame Rate Video Technology  

NASA Technical Reports Server (NTRS)

Papers and working group summaries presented at the High Resolution, High Frame Rate Video (HHV) Workshop are compiled. HHV system is intended for future use on the Space Shuttle and Space Station Freedom. The Workshop was held for the dual purpose of: (1) allowing potential scientific users to assess the utility of the proposed system for monitoring microgravity science experiments; and (2) letting technical experts from industry recommend improvements to the proposed near-term HHV system. The following topics are covered: (1) State of the art in the video system performance; (2) Development plan for the HHV system; (3) Advanced technology for image gathering, coding, and processing; (4) Data compression applied to HHV; (5) Data transmission networks; and (6) Results of the users' requirements survey conducted by NASA.

1990-01-01

39

Appendicularian ecophysiology I: Food concentration dependent clearance rate, assimilation efficiency, growth and reproduction of Oikopleura dioica  

NASA Astrophysics Data System (ADS)

Three aspects of the appendicularian O. dioica' s ecophysiology were measured here: 1) morphological parameters over a wide range of appendicularian sizes, including mature animals in order to document the morphological characteristics inducing reproduction; 2) clearance rate and assimilation efficiency using feeding incubations with different algal concentrations and 3) the effect of food concentration on growth, mortality and reproduction. The relationship between the body carbon weight and the clearance rate follows a power function, with an exponent of 0.91 (± 0.07). The rate of particles retention increases with the food concentration following a Michaelis-Menten relationship (half-saturation constant = 151 ± 22 µg C l - 1 , maximum clearance rate = 12 ± 1 µg C µg C - 1 d - 1 ). The carbon assimilation efficiency decreases with the increasing food concentration. As a result, appendicularian growth which is limited in concentrations lower than 50 µg C l - 1 is saturated above 100 µg C l - 1 . In immature animals the gonad represents less than 30% of the body volume whereas in mature individuals, its volume varies between 50% and 87% (mean 63%) suggesting that gonad/total volume ratio can be used as indicator of the maturation stages. The gonad weight in mature animals represents 70.3 (± 4.6)% of the total body carbon weight. Two major maturity stages can explain the changes in energy allocation: i) the somatic growth, when less energy is invested in gonad growth when compared to the rest of the body and ii) the maturation phase where most of the assimilated matter is invested in gonad maturation. This process is rapid, lasting only few hours. For this reason we measured completely mature organisms that are generally not measured during the experimental work with appendicularians. In food-limited conditions, the gonad maturation process starts with smaller individuals and ends with smaller reproductive animals having the same gonad to total volume ratio than in unlimited food conditions. The results obtained in this study were used to model the life cycle of O. dioica (see Lombard, F., Sciandra, A. and Gorsky, G., 2009-this volume. Appendicularian ecophysiology. II. Modeling nutrition, metabolism, growth and reproduction of the appendicularian Oikopleura dioica.).

Lombard, Fabien; Renaud, Florent; Sainsbury, Christopher; Sciandra, Antoine; Gorsky, Gabriel

2009-11-01

40

Preweaning productivity of suckling goats and sheep in Guadeloupe (FWI) under intensive reproductive rate and grazing management.  

PubMed

In Guadeloupe, small ruminants are reared for meat production under pasture conditions. Intensive rotative grazing systems (irrigated, fertilized and high-stocked tropical pastures) allow satisfactory levels of production but generate high post-grazing residues. Experiments were designed to control these. A system in which residuals were mown (RM) was tested in comparison to the control system (residuals remained, RR). The same design was carried out over two years with Creole goats and Martinik sheep. An accelerated reproductive rate (3 parturitions over 2 years) was carried out. Systems were compared at three parturition seasons per year (dry, intermediate and rainy seasons). Each group was composed of 20 goats (36.0+/-2.5 kg) or 20 ewes (46.8+/-2.4 kg). The systems exhibited high levels of productivity in both species compared to other results in the tropics: more than 50 and 30 offspring born alive per hectare and per reproductive season for the goat and ewe flocks, respectively. The annual production at birth was 110 kg kids/ha per year and 133 kg lambs/ha per year (i.e. 21% more). Corresponding values at weaning were 630 kg kids/ha per year and 785 kg lambs/ha per year (i.e. 25% more). The RM system produced 10% more than the RR system in Creole goats, while it produced 35% more in Martinik sheep. Seasonal effects and other factors of variation are discussed. PMID:15742870

Ortega-Jimenez, E; Alexandre, G; Arquet, R; Mahieu, M; Xandé, A

2005-02-01

41

High accuracy optical rate sensor  

NASA Technical Reports Server (NTRS)

Optical rate sensors, in particular CCD arrays, will be used on Space Station Freedom to track stars in order to provide inertial attitude reference. An algorithm to provide attitude rate information by directly manipulating the sensor pixel intensity output is presented. The star image produced by a sensor in the laboratory is modeled. Simulated, moving star images are generated, and the algorithm is applied to this data for a star moving at a constant rate. The algorithm produces accurate derived rate of the above data. A step rate change requires two frames for the output of the algorithm to accurately reflect the new rate. When zero mean Gaussian noise with a standard deviation of 5 is added to the simulated data of a star image moving at a constant rate, the algorithm derives the rate with an error of 1.9 percent at a rate of 1.28 pixels per frame.

Uhde-Lacovara, J.

1990-01-01

42

Synchronized reproduction promotes species coexistence through reproductive facilitation  

E-print Network

Synchronized reproduction promotes species coexistence through reproductive facilitation Yu synchronized reproduction. The facilitation on reproduction may enhance species persistence and coexistence- meters, such as mortality and recruitment rates, and functions of reproductive facilitation. Both

Hsu, Sze-Bi

43

Frost resistance of reproductive tissues during various stages of development in high mountain plants.  

PubMed

Frost resistance of reproductive vs aboveground vegetative structures was determined for six common European high alpine plant species that can be exposed to frosts throughout their whole reproductive cycle. Freezing tests were carried out in the bud, anthesis and fruit stage. Stigma and style, ovary, placenta, ovule, flower stalk/peduncle and, in Ranunculus glacialis, the receptacle were separately investigated. In all species, the vegetative organs tolerated on an average 2-5 K lower freezing temperatures than the most frost-susceptible reproductive structures that differed in their frost resistance. In almost all species, stigma, style and the flower stalk/peduncle were the most frost-susceptible reproductive structures. Initial frost damage (LT??) to the most susceptible reproductive structure usually occurred between -2 and -4°C independent of the reproductive stage. The median LT?? across species for stigma and style ranged between -3.4 and -3.7°C and matched the mean ice nucleation temperature (-3.7 ± 1.4°C). In R. glacialis, the flower stalk was the most frost-susceptible structure (-5.4°C), and was in contrast to the other species ice-tolerant. The ovule and the placenta were usually the most frost-resistant structures. During reproductive development, frost resistance (LT??) of single reproductive structures mostly showed no significant change. However, significant increases or decreases were also observed (2.1 ± 1.2 K). Reproductive tissues of nival species generally tolerated lower temperatures than species occurring in the alpine zone. The low frost resistance of reproductive structures before, during and shortly after anthesis increases the probability of frost damage and thus, may restrict successful sexual plant reproduction with increasing altitude. PMID:22420836

Neuner, Gilbert; Erler, Agnes; Ladinig, Ursula; Hacker, Jürgen; Wagner, Johanna

2013-01-01

44

High strain rate effects for composite materials  

Microsoft Academic Search

We have been developing the capability to characterize the high strain rate response of continuous fiber polymer composites. The data presented covers strain rates from 0\\/sec to 3000\\/sec. A combination of test machines and specimen geometries was investigated. Strain rates from 0--100\\/sec were generated using conventional and high speed hydraulic test machines. Strain rates from 10--1000\\/sec were generated using a

S. E. Groves; R. J. Sanchez; R. E. Lyon; A. E. Brown

1992-01-01

45

Foolproof completions for high rate production wells  

E-print Network

gravel pack (GP) and high rate water pack (HRWP) completions over high-permeability fracturing (HPF), known in the vernacular as a frac&pack (FP) for very high rate wells. While a properly designed GP completion may prevent sand production, it does...

Tosic, Slavko

2008-10-10

46

Foolproof completions for high rate production wells  

E-print Network

gravel pack (GP) and high rate water pack (HRWP) completions over high-permeability fracturing (HPF), known in the vernacular as a frac&pack (FP) for very high rate wells. While a properly designed GP completion may prevent sand production, it does...

Tosic, Slavko

2009-05-15

47

High variation in clonal vs. sexual reproduction in populations of the wild strawberry, Fragaria virginiana (Rosaceae)  

E-print Network

was characterized in three populations of the wild strawberry, Fragaria virginiana, to determine the extent, Fragaria virginiana, microsatellites, population genetic structure. INTRODUCTION Many plant speciesHigh variation in clonal vs. sexual reproduction in populations of the wild strawberry, Fragaria

Ashley, Mary V.

48

Seasonal variability in the fertilization rate of women undergoing assisted reproduction treatments.  

PubMed

The objective of this study was to evaluate whether seasonality affects human-assisted reproduction treatment outcomes. For this, 1932 patients undergoing intracytoplasmic sperm injection (ICSI) were assigned to a season group according to the day of oocyte retrieval: winter (n = 435), spring (n = 444), summer (n = 469) or autumn (n = 584). Analysis of variance was used to compare the ICSI outcomes. The fertilization rate was increased during the spring (winter: 67.9%, spring: 73.5%, summer: 68.7% and autumn: 69.0%; p < 0.01). In fact, a nearly 50% increase in the fertilization rate during the spring was observed (odds ratio 1.45, confidence interval 1.20-1.75; p < 0.01). The oestradiol concentration per number of oocytes was significantly higher during the spring (winter: 235.8 pg/mL, spring: 282.1 pg/mL, summer: 226.1 pg/mL and autumn: 228.7 pg/mL; p = 0.030). This study demonstrates a seasonal variability in fertilization after ICSI, where fertilization is higher during the spring than at any other time. PMID:22296507

Braga, Daniela Paes De Almeida Ferreira; Setti, Amanda; Figueira, Rita de Cássia Sávio; Iaconelli, Assumpto; Borges, Edson

2012-07-01

49

Effects of subcutaneous transmitters on reproduction, incubation behavior, and annual return rates of female wood ducks  

USGS Publications Warehouse

Radiotransmitters attached externally to breeding waterfowl can have a variety of negative effects. Implanted transmitters can reduce potential deleterious effects; abdominal implants are used most commonly in waterfowl. Methods also have been developed to implant transmitters subcutaneously, but effects of subcutaneous implants on adult ducks have not been evaluated. In this study, we subcutaneously implanted radiotransmitters in pre-laying female wood ducks (Aix sponsa, n = 62) and compared nest initiation date, incubation behavior, body mass, and annual return rates of radiomarked females to a group of females that were not radiomarked. Ninety-six percent (50 of 52) of radiomarked females that were monitored for the entire breeding season initiated nests. Nesting date of radiomarked adult females did not differ from that of adult females without radios, but radiomarked yearling females nested earlier than yearlings not receiving transmitters. We found no differences in early- and late-incubation body mass, incubation constancy, recess frequency, and incubation period between radiomarked females and those without radios. Annual return rates of females that initiated nests did not differ between radiomarked females and those not receiving radios. Data suggest that implanting radiotransmitters subcutaneously in pre-laying female wood ducks did not negatively impact subsequent reproduction, incubation behavior, and survival.

Hepp, G.R.; Folk, T.H.; Hartke, K.M.

2002-01-01

50

Cumulative live birth rate and assisted reproduction: impact of female age and transfer day  

PubMed Central

Background: Many studies on assisted reproductive technology examine live birth rate per cycle. However, after a cycle fails, couples often want to know what their chances are of having a live birth if they continue treatment. From a patients’ perspective, the cumulative probability of live birth is more informative. Materials and Methods: This study includes patients who underwent fresh, frozen and non-donor ICSI cycles at our IVF unit between 2006-2012. Patients were divided into two groups; Group 1 represented those who underwent only Day 5 transfers, Group 2 represented only Day 3 transfers. Patients who underwent both were excluded. ­Cycles were analyzed until the first live birth or the end of the 3rd cycle. Using Kaplan-Meier analysis, we estimated the cumulative live birth rates for each group and according to female age. Results: The mean age for Group 1 was significantly lower than for Group 2. After 3 cycles, Group 1’s CLBR was 79% versus 66% in Group 2. When analyzing the live births by age and group, there was a significant difference in the CLBR after 3 cycles with the women less than 35 years having the highest CLBR and the women 40 years or older having the lowest CLBR. Conclusion: In women less than 35 years, excellent CLBR can be achieved irrespective of the transfer day. For women 40 years and above, better results of CLBR are observed with Day 5 transfers. Our findings may impact the counseling of couples considering IVF treatment. PMID:25374657

Abuzeid, M.I.; Bolonduro, O.; La Chance, J.; Abozaid, T.; Urich, M.; Ullah, K.; Ali, T.; Ashraf, M.; Khan, I.

2014-01-01

51

A high-strain-rate superplastic ceramic  

Microsoft Academic Search

High-strain-rate superplasticity describes the ability of a material to sustain large plastic deformation in tension at high strain rates of the order of 10-2 to 10-1s-1 and is of great technological interest for the shape-forming of engineering materials. High-strain-rate superplasticity has been observed in aluminium-based and magnesium-based alloys. But for ceramic materials, superplastic deformation has been restricted to low strain

B.-N. Kim; K. Hiraga; K. Morita; Y. Sakka

2001-01-01

52

ESTIMATION OF REPRODUCTIVE RATES OF BURROWING OWLS LEAH R. GORMAN,1 Oregon Cooperative Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University,  

E-print Network

ESTIMATION OF REPRODUCTIVE RATES OF BURROWING OWLS LEAH R. GORMAN,1 Oregon Cooperative Wildlife to observe, such as the burrowing owl (Athene cunicularia). We compared methods for estimating reproductive rates of burrowing owls, defined as the number of 21- to 28-day-old young per successful nest. We com

Rosenberg, Daniel K.

53

Cusp for high and low merging rates  

NASA Astrophysics Data System (ADS)

The traditional distinction between the cusp for northward and southward interplanetary magnetic field (IMF) conditions is deficient in that many, if not most, ``northward'' IMF cusp encounters closely resemble southward IMF encounters. Partly for that reason, ``southward'' IMF cusps have been far more often examined than ``northward. '' Recently, Newell et al. (2007) showed that the magnetopause merging rate, d?MP/dt, much better predicts cusp latitude than does B z (or Bs). Here, we investigate the extent to which high and low merging rate conditions better separates cusp encounters into mutually distinct classes. Indeed, high merging rate cusps (those with d?MP/dt > 2* $\\langle$ d?MP/dt $\\rangle$) differ from low merging rate cusps (those with d?MP/dt < 0.5$\\langle$ d?MP/dt $\\rangle$) in several quantitative and even qualitative ways. High-energy (tens of keV) ions, apparently of magnetospheric origin, do not extend into the high merging rate cusp but frequently do for low merging rates. However, the dispersion curve for ions, apparently of magnetosheath origin, extends to several keV for high merging rates but only to 1-2 keV for low merging rates. The local time extent of the cusp is 2.33 hours MLT for low merging rate conditions and 3.45 hours MLT for high merging rate conditions. All high merging rate cusps show clear forward dispersion (declining energy with increasing latitude) with low-energy ion cutoffs within that dispersion. Low merging rates cusps rarely show forward dispersion, but about half, or slightly less, show reverse dispersion (declining energy with decreasing latitude) at the poleward edge of the cusp. Low-energy ion cutoffs in the low-merging rate cusp primarily occur only within that reverse dispersion. ``Double'' cusps, some with very clear latitudinal separation, occur in some high merging rate cases, but no low merging rate cases. The high merging rates cases also typically have a ``shadow'' region of electron-only precipitation at roughly polar rain energies and intensities, lying immediately equatorward of the main cusp. For low-merging rate conditions, the region immediately equatorward of the cusp (main magnetosheath ion population) contains ions as well as electrons, and forms a boundary layer.

Newell, P. T.; Wing, S.; Rich, F. J.

2007-09-01

54

High variation in clonal vs. sexual reproduction in populations of the wild strawberry, Fragaria virginiana (Rosaceae)  

PubMed Central

Background and Aims Many plants reproduce both clonally and sexually, and the balance between the two modes of reproduction will vary among populations. Clonal reproduction was characterized in three populations of the wild strawberry, Fragaria virginiana, to determine the extent that reproductive mode varied locally between sites. The study sites were fragmented woodlands in Cook County, Illinois, USA. Methods A total of 95 strawberry ramets were sampled from the three sites via transects. Ramets were mapped and genotyped at five variable microsatellite loci. The variability at these five loci was sufficient to assign plants to clones with high confidence, and the spatial pattern of genets was mapped at each site. Key Results A total of 27 distinct multilocus genotypes were identified. Of these, 18 genotypes were detected only once, with the remaining nine detected in multiple ramets. The largest clone was identified in 16 ramets. No genets were shared between sites, and each site exhibited markedly different clonal and sexual recruitment patterns, ranging from two non-overlapping and widespread genets to 19 distinct genets. Only one flowering genet was female; the remainder were hermaphrodites. Conclusions Local population history or fine-scale ecological differences can result in dramatically different reproductive patterns at small spatial scales. This finding may be fairly widespread among clonal plant species, and studies that aim to characterize reproductive modes in species capable of asexual reproduction need to evaluate reproductive modes in multiple populations and sites. PMID:19797422

Wilk, John A.; Kramer, Andrea T.; Ashley, Mary V.

2009-01-01

55

High strain rate effects for composite materials  

SciTech Connect

We have been developing the capability to characterize the high strain rate response of continuous fiber polymer composites. The data presented covers strain rates from 0/sec to 3000/sec. A combination of test machines and specimen geometries was investigated. Strain rates from 0--100/sec were generated using conventional and high speed hydraulic test machines. Strain rates from 10--1000/sec were generated using a high energy drop tower, and rates from 1000--3000/sec were generated using a split Hopkinson bar. Strain rates above 100/sec have only been generated for uniaxial compression. Our efforts have primarily focused on developing the high energy drop tower for these purposes. Specimen geometries for compression include tapered cubes, one inch tubes, and solid rods. For tension a smaller 0.5 in. diameter version of our 2.0 in. diameter multiaxial test specimen was developed and has been successfully used at strain rates up to 100 per second. Fixtures were also developed for performing high strain rate shear testing and through thickness penetration studies of composite plates. The objective of these experiments is to develop dynamic material models for use in finite element design tools. This presentation will focus on the methods and results obtained from this study.

Groves, S.E.; Sanchez, R.J.; Lyon, R.E.; Brown, A.E.

1992-04-16

56

High strain rate properties of composites  

NASA Astrophysics Data System (ADS)

Polymer matrix composites are presently used in many fields due to their excellent mechanical properties such as high specific strength and stiffness. However, not much is known of these composites' response to impact loading, which usually occurs at strain rates much higher than the strain rates used to measure the quasi-static mechanical properties of materials. The use of static properties in the study of structures that undergo dynamic loading can produce excessive design weight or cause unexplained and untimely failure. The studies included in this dissertation provide the results of Split Hopkinson Pressure Bar experiments to determine the ultimate compressive strength and strain of composites at high strain rates. Most researchers are using specimens with different dimensions and geometry. For this reason, it is difficult to compare results of tests done by different people. Herein, the Split Hopkinson Pressure Bar facility at the University of Delaware is used to study the effect of specimen geometry at high strain rate tests. In addition, research is conducted at different fiber orientations to have a better understanding of the effect of high strain rate in loading directions different from the primary material axes. Environmental effects, specifically moisture effects, on the dynamic properties of composites are also investigated extensively for the first time and provide interesting results. There are no fundamental theories of failure and principles defining the general behavior of composites at high strain rates at the present. However, a new equation based on experimental results is introduced to predict material behavior at high strain rates.

Woldesenbet, Eyassu

57

High-rate lithium thionyl chloride cells  

NASA Technical Reports Server (NTRS)

A high-rate C cell with disc electrodes was developed to demonstrate current rates which are comparable to other primary systems. The tests performed established the limits of abuse beyond which the cell becomes hazardous. Tests include: impact, shock, and vibration tests; temperature cycling; and salt water immersion of fresh cells.

Goebel, F.

1982-01-01

58

Multichannel analyzers at high rates of input  

NASA Technical Reports Server (NTRS)

Multichannel analyzer, used with a gating system incorporating pole-zero compensation, pile-up rejection, and baseline-restoration, achieves good resolution at high rates of input. It improves resolution, reduces tailing and rate-contributed continuum, and eliminates spectral shift.

Rudnick, S. J.; Strauss, M. G.

1969-01-01

59

High strain rate properties of composites  

Microsoft Academic Search

Polymer matrix composites are presently used in many fields due to their excellent mechanical properties such as high specific strength and stiffness. However, not much is known of these composites' response to impact loading, which usually occurs at strain rates much higher than the strain rates used to measure the quasi-static mechanical properties of materials. The use of static properties

Eyassu Woldesenbet

1998-01-01

60

High repetition rate miniature triggered spark switch  

NASA Astrophysics Data System (ADS)

A miniature triggered spark switch designed to operate at high repetition rates has been constructed. The device, along with associated triggered circuitry, has been incorporated into a simple LC generator which produces an oscillatory discharge at a frequency of 150 MHz. The switch is operated in the pressure range 760 torr-2.6 x 10 to the 3rd torr using commercial dry nitrogen as the working gas. Both brass (70/30) and aluminum (99.95 percent) electrodes were investigated for repetition frequencies as high as 20 kHz and for gas flow rates as high as 8 cu cm/s. The effect of repetition rate on switch jitter and switch breakdown voltage is presented and discussed in terms of gas pressure and flow rate.

Rose, M. F.; Glancy, M. T.

1980-09-01

61

Reproductive Peformance of Great Egrets (Ardea alba) at High Island, Texas.  

E-print Network

??Despite habitat perturbations and seasonal fluctuations in reproduction, many studies report no significant inter-annual variation in Great Egret reproductive performance. I examined the reproductive performance… (more)

McInnes, Andrew

2012-01-01

62

Stress and success: Individual differences in the glucocorticoid stress response predict behavior and reproductive success under high predation risk.  

PubMed

A fundamental element of how vertebrates respond to stressors is by rapidly elevating circulating glucocorticoid hormones. Individual variation in the magnitude of the glucocorticoid stress response has been linked with reproductive success and survival. But while the adaptive value of this response is believed to stem in part from changes in the expression of hormone-mediated behaviors, it is not clear how the behavior of stronger and weaker glucocorticoid responders differs during reproduction, or during exposure to ecologically relevant stressors. Here we report that in a population of barn swallows (Hirundo rustica erythrogaster) experiencing high rates of nest predation, circulating levels of corticosterone (the primary avian glucocorticoid) during exposure to a standardized stressor predict aspects of subsequent behavior and fitness. Individuals that mounted a stronger corticosterone stress response during the early reproductive period did not differ in clutch size, but fledged fewer offspring. Parents with higher stress-induced corticosterone during the early reproductive period later provisioned their nestlings at lower rates. Additionally, in the presence of a model predator stress-induced corticosterone was positively associated with the latency to return to the nest, but only among birds that were observed to return. Model comparisons revealed that stress-induced hormones were better predictors of the behavioral and fitness effects of exposure to transient, ecologically relevant stressors than baseline corticosterone. These findings are consistent with functional links between individual variation in the hormonal and behavioral response to stressors. If such links occur, then selection on the heritable components of the corticosterone stress response could promote adaptation to novel environments or predation regimes. PMID:25461975

Vitousek, Maren N; Jenkins, Brittany R; Safran, Rebecca J

2014-11-01

63

THE INFLUENCE OF MODEL TIME STEP ON THE RELATIVE SENSITIVIY OF POPULATION GROWTH RATE TO REPRODUCTION  

EPA Science Inventory

In recent years there has been an increasing interest in using population models in environmental assessments. Matrix population models represent a valuable tool for extrapolating from life stage-specific stressor effects on survival and reproduction to effects on finite populati...

64

Use of Video Probe Does Not Affect Burrowing Owl Reproductive Parameters or Return Rates  

Microsoft Academic Search

We tested how repeated use of an infrared video probe influenced burrowing owl (Athene cunicularia) reproduction and recruitment. In 2001, we randomly assigned occupied burrows in Washington State, USA, to one of 2 groups: 1) inspected throughout the breeding season with an infrared video probe (n ¼ 38), or 2) never inspected with a probe (n ¼ 41). We did

Victoria Garcia; Courtney J. Conway

2009-01-01

65

A high-strain-rate superplastic ceramic.  

PubMed

High-strain-rate superplasticity describes the ability of a material to sustain large plastic deformation in tension at high strain rates of the order of 10-2 to 10-1 s-1 and is of great technological interest for the shape-forming of engineering materials. High-strain-rate superplasticity has been observed in aluminium-based and magnesium-based alloys. But for ceramic materials, superplastic deformation has been restricted to low strain rates of the order of 10-5 to 10-4 s-1 for most oxides and nitrides with the presence of intergranular cavities leading to premature failure. Here we show that a composite ceramic material consisting of tetragonal zirconium oxide, magnesium aluminate spinel and alpha-alumina phases exhibits superplasticity at strain rates up to 1 s-1. The composite also exhibits a large tensile elongation, exceeding 1,050 per cent for a strain rate of 0.4 s-1. The tensile flow behaviour and deformed microstructure of the material indicate that superplasticity is due to a combination of limited grain growth in the constitutive phases and the intervention of dislocation-induced plasticity in the zirconium oxide phase. We suggest that the present results hold promise for the application of shape-forming technologies to ceramic materials. PMID:11565026

Kim, B N; Hiraga, K; Morita, K; Sakka, Y

2001-09-20

66

High-Repetition-Rate Femtosecond Yb  

E-print Network

-referenced optical frequency combs, OPO pumping, time-resolved pump-probe studies, CARS spectroscopy, super.hw.ac.uk BENEFITS & APPLICATIONS: Originally developed for semiconductor probing, this compact high-repetition- rate Professor Derryck Reid's group, the ultrafast fibre laser is suitable for use in applications such as self

Painter, Kevin

67

Baltimore District Tackles High Suspension Rates  

ERIC Educational Resources Information Center

This article reports on how the Baltimore District tackles its high suspension rates. Driven by an increasing belief that zero-tolerance disciplinary policies are ineffective, more educators are embracing strategies that do not exclude misbehaving students from school for offenses such as insubordination, disrespect, cutting class, tardiness, and…

Maxwell, Lesli A.

2007-01-01

68

A Visibility Matching Tone Reproduction Operator for High Dynamic Range Scenes  

Microsoft Academic Search

We present a tone reproduction operator that preserves visibility in high dynamic range scenes. Our method introduces a new histogram adjustment technique, based on the population of local adaptation luminances in a scene. To match subjective viewing experience, the method incorporates models for human contrast sensitivity, glare, spatial acuity and color sensitivity. We compare our results to previous work and

Gregory Ward Larson; Holly E. Rushmeier; Christine D. Piatko

1997-01-01

69

Effects of feeding high-linoleate safflower seeds on postpartum reproduction in beef cows  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two experiments were conducted to evaluate reproductive responses to supplemental high-linoleate safflower seeds in postpartum beef cows. In Exp. 1, 18 primiparous, crossbred beef cows (BW 411 ± 24.3 kg) were fed Foxtail millet hay at 1.68% of BW (DM basis) and either a low-fat control (Control: 63...

70

Complete genome sequence of a novel highly pathogenic porcine reproductive and respiratory syndrome virus variant.  

PubMed

Highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) emerged in China in 2006, and HP-PRRS virus (HP-PRRSV) has evolved continuously. Here, the complete genomic sequence of a novel HP-PRRSV field strain, JX, is reported. The present finding will contribute to further studies focusing on the evolutionary mechanism of PRRSV. PMID:23118452

Wang, Lianghai; Hou, Jun; Zhang, Hexiao; Feng, Wen-hai

2012-12-01

71

Chromatic adaptation-based tone reproduction for high-dynamic-range imaging  

NASA Astrophysics Data System (ADS)

We present an adaptive tone reproduction algorithm for displaying high-dynamic-range (HDR) images on conventional low-dynamic-range (LDR) display devices. The proposed algorithm consists of an adaptive tone reproduction operator and chromatic adaptation. The algorithm for dynamic range reduction relies on suitable tone reproduction functions that depend on histogram-based parameter estimation to adjust luminance according to global and local features. Instead of relying only on reduction of dynamic range, this chromatic adaption technique also preserves chromatic appearance and color consistency across scene and display environments. Our experimental results demonstrate that the proposed algorithm achieves good subjective quality while preserving image details. Furthermore, the proposed algorithm is simple and practical for implementation.

Lee, Joohyun; Jeon, Gwanggil; Jeong, Jechang

2009-10-01

72

Main role of self-pollination rate on reproductive allocations in pseudogamous apomicts  

Microsoft Academic Search

Most apomicts are hermaphroditic and pseudogamous (pollination is necessary to trigger parthenogenesis). In these plants,\\u000a fitness depends on the number of progeny obtained by maternal reproduction. We determined the evolutionary stable strategy\\u000a for male and female sex allocation. We show that the efficiency of pollination determines male and female resource allocations.\\u000a Predictions are made of these allocations, of pollen\\/ovule ratio

M. Noirot; D. Couvet; S. Hamon

1997-01-01

73

Highly stable high-rate discriminator for nuclear counting  

NASA Technical Reports Server (NTRS)

Pulse amplitude discriminator is specially designed for nuclear counting applications. At very high rates, the threshold is stable. The output-pulse width and the dead time change negligibly. The unit incorporates a provision for automatic dead-time correction.

English, J. J.; Howard, R. H.; Rudnick, S. J.

1969-01-01

74

High strain rate behaviour of polypropylene microfoams  

NASA Astrophysics Data System (ADS)

Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc.) or personal safety (helmets, knee-pads, etc.). In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry) is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s-1) in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB). Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.

Gómez-del Río, T.; Garrido, M. A.; Rodríguez, J.; Arencón, D.; Martínez, A. B.

2012-08-01

75

Late snowmelt delays plant development and results in lower reproductive success in the High Arctic.  

PubMed

In tundra areas where the growing season is short, any delay in the start of summer may have a considerable effect on plant development, growth and reproductive success. Climate models suggest long-term changes in winter precipitation in the Arctic, which may lead to deeper snow cover and a resultant delay in date of snow melt. In this paper, we investigated the role of snow depth and melt out date on the phenological development and reproductive success of vascular plants in Adventdalen, Svalbard (78° 10'N, 16° 06'E). Effects of natural variations in snow accumulation were demonstrated using two vegetation types (snow depth: meadow 21 cm, heath 32 cm), and fences were used to experimentally increase snow depth by over 1m. Phenological delay was greatest directly after snowmelt in the earlier phenological phases, and had the largest effect on the early development of those species which normally green-up early (i.e. Dryas, Papaver, Salix, Saxifraga). Compressed growing seasons and length of the reproductive period led to a reduced reproductive success in some of the study species. There were fewer flowers, fewer plots with dispersing seeds, and lower germination rates. This can have consequences for plant establishment and community composition in the long-term. PMID:21421357

Cooper, Elisabeth J; Dullinger, Stefan; Semenchuk, Philipp

2011-01-01

76

Phosphor thermometry at high repetition rates  

NASA Astrophysics Data System (ADS)

Phosphor thermometry is a semi-invasive surface temperature measurement technique utilizing the luminescence properties of thermographic phosphors. Typically these ceramic materials are coated onto the object of interest and are excited by a short UV laser pulse. Photomultipliers and high-speed camera systems are used to transiently detect the subsequently emitted luminescence decay point wise or two-dimensionally resolved. Based on appropriate calibration measurements, the luminescence lifetime is converted to temperature. Up to now, primarily Q-switched laser systems with repetition rates of 10 Hz were employed for excitation. Accordingly, this diagnostic tool was not applicable to resolve correlated temperature transients at time scales shorter than 100 ms. For the first time, the authors realized a high-speed phosphor thermometry system combining a highly repetitive laser in the kHz regime and a fast decaying phosphor. A suitable material was characterized regarding its temperature lifetime characteristic and precision. Additionally, the influence of laser power on the phosphor coating in terms of heating effects has been investigated. A demonstration of this high-speed technique has been conducted inside the thermally highly transient system of an optically accessible internal combustion engine. Temperatures have been measured with a repetition rate of one sample per crank angle degree at an engine speed of 1000 rpm. This experiment has proven that high-speed phosphor thermometry is a promising diagnostic tool for the resolution of surface temperature transients.

Fuhrmann, N.; Brübach, J.; Dreizler, A.

2013-09-01

77

High temperature electrochemical corrosion rate probes  

SciTech Connect

Corrosion occurs in the high temperature sections of energy production plants due to a number of factors: ash deposition, coal composition, thermal gradients, and low NOx conditions, among others. Electrochemical corrosion rate (ECR) probes have been shown to operate in high temperature gaseous environments that are similar to those found in fossil fuel combustors. ECR probes are rarely used in energy production plants at the present time, but if they were more fully understood, corrosion could become a process variable at the control of plant operators. Research is being conducted to understand the nature of these probes. Factors being considered are values selected for the Stern-Geary constant, the effect of internal corrosion, and the presence of conductive corrosion scales and ash deposits. The nature of ECR probes will be explored in a number of different atmospheres and with different electrolytes (ash and corrosion product). Corrosion rates measured using an electrochemical multi-technique capabilities instrument will be compared to those measured using the linear polarization resistance (LPR) technique. In future experiments, electrochemical corrosion rates will be compared to penetration corrosion rates determined using optical profilometry measurements.

Bullard, Sophie J.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Ziomek-Moroz, M.

2005-09-01

78

Microstructural evolution in high strength materials at high strain rates  

NASA Astrophysics Data System (ADS)

High strength materials such as used as armor plate have been investigated in torsion using Split Hopkinson Bars for the purpose of obtaining stress-strain curves and for examining the mechanism of plastic deformation in terms of mechanical instability due to thermal softening at high strain rates. A comparative study of the plastic deformation behavior of RHA steel, Aluminum 5083 H131 alloy and Tungsten A90S alloy under the loading condition at high strain rates is carried out and the effect of strain rate on shear flow stress and stress-strain profiles is presented. Strain rate sensitivities of the materials are evaluated and discussed with respect to mechanical instability and adiabatic shear strain localization.

Bassim, M. N.; Bolduc, M.; Odeshi, A. G.; Mirfarkraei, S.

2006-08-01

79

Genetic variation and pathogenicity of highly virulent porcine reproductive and respiratory syndrome virus emerging in China  

Microsoft Academic Search

A highly pathogenic swine disease designated as ‘porcine high fever disease (PHFD)’ appeared recently in China. Porcine reproductive\\u000a and respiratory syndrome virus (PRRSV) was identified as an agent associated with PHFD, and two discontiguous sequence deletions\\u000a were identified as a genetic marker in the Nsp2 region of the viral genome. To examine PHFD in Shandong province, a total\\u000a of 10

J. Wu; J. Li; F. Tian; S. Ren; M. Yu; J. Chen; Z. Lan; X. Zhang; Dongwan Yoo; Jinbao Wang

2009-01-01

80

Molecular characterization of a highly pathogenetic porcine reproductive and respiratory syndrome virus variant in Hubei, China  

Microsoft Academic Search

Porcine reproductive and respiratory syndrome virus (PRRSV) has been recognized as one of the most important pathogens of\\u000a pigs throughout the world. In 2006, more than 10 provinces of China have experienced an epizootic outbreak of pig diseases\\u000a characterized by high fever, reddened skin and high morbidity and mortality. From June 2006 to April 2007, we have investigated\\u000a some clinical

Yi Huang; Bing Zhang; Zhen-fang Fu; Simon Rayner; Fang-liang Zheng; Wang-wang Liang; Ke-li Yang; Di-ping Xu; Han-zhong Wang

2009-01-01

81

A high-throughput method for assessing chemical toxicity using a Caenorhabditis elegans reproduction assay  

SciTech Connect

The National Research Council has outlined the need for non-mammalian toxicological models to test the potential health effects of a large number of chemicals while also reducing the use of traditional animal models. The nematode Caenorhabditis elegans is an attractive alternative model because of its well-characterized and evolutionarily conserved biology, low cost, and ability to be used in high-throughput screening. A high-throughput method is described for quantifying the reproductive capacity of C. elegans exposed to chemicals for 48 h from the last larval stage (L4) to adulthood using a COPAS Biosort. Initially, the effects of exposure conditions that could influence reproduction were defined. Concentrations of DMSO vehicle {<=} 1% did not affect reproduction. Previous studies indicated that C. elegans may be influenced by exposure to low pH conditions. At pHs greater than 4.5, C. elegans reproduction was not affected; however below this pH there was a significant decrease in the number of offspring. Cadmium chloride was chosen as a model toxicant to verify that automated measurements were comparable to those of traditional observational studies. EC{sub 50} values for cadmium for automated measurements (176-192 {mu}M) were comparable to those previously reported for a 72-h exposure using manual counting (151 {mu}M). The toxicity of seven test toxicants on C. elegans reproduction was highly correlative with rodent lethality suggesting that this assay may be useful in predicting the potential toxicity of chemicals in other organisms.

Boyd, Windy A. [Biomolecular Screening Branch, National Toxicology Program, Research Triangle Park, NC 27709 (United States); McBride, Sandra J.; Rice, Julie R.; Snyder, Daniel W. [Biomolecular Screening Branch, National Toxicology Program, Research Triangle Park, NC 27709 (United States); Freedman, Jonathan H., E-mail: freedma1@niehs.nih.go [Biomolecular Screening Branch, National Toxicology Program, Research Triangle Park, NC 27709 (United States); Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709 (United States)

2010-06-01

82

High temperature high strain rate testing with a compressive SHPB  

NASA Astrophysics Data System (ADS)

Both temperature and strain rate have a significant effect on the mechanical behavior of most materials. At or close to room temperature, well-designed and well-built SHPB devices can be used to produce high quality high strain rate data relatively easily, but at elevated temperatures many practical difficulties make such tests much more complicated. There is, however, an increasing interest and practical need to study and model the high strain rate behavior of materials also at high temperatures, and therefore development of sophisticated high strain rate high temperature testing devices is needed. In this paper, a fully computer controlled Split Hopkinson Pressure Bar (SHPB) testing system with a high température capability up to1000°C is described The high température (HT) system is based on fast pneumatic specimen and pressure bar manipulation devices which en able heating up of the specimen only and limit the contact time of the hot specimen with cold pressure bars to50...100ms Some results of the tests made with the new HT-SHPB device are also presented in this paper.

Apostol, M.; Vuoristo, T.; Kuokkala, V.-T.

2003-09-01

83

Frequent sexual reproduction and high intraspecific variation in Salix arctica: Implications for a terrestrial feedback to climate change  

E-print Network

Frequent sexual reproduction and high intraspecific variation in Salix arctica: Implications and high intraspecific variation in Salix arctica: Implications for a terrestrial feedback to climate ecosystems respond to climate change. Here, we characterized genetic and phenotypic variation in Salix

Hufbauer, Ruth A.

84

High rate pulse processing algorithms for microcalorimeters  

SciTech Connect

It has been demonstrated that microcalorimeter spectrometers based on superconducting transition-edge-sensor can readily achieve sub-100 eV energy resolution near 100 keV. However, the active volume of a single microcalorimeter has to be small to maintain good energy resolution, and pulse decay times are normally in the order of milliseconds due to slow thermal relaxation. Consequently, spectrometers are typically built with an array of microcalorimeters to increase detection efficiency and count rate. Large arrays, however, require as much pulse processing as possible to be performed at the front end of the readout electronics to avoid transferring large amounts of waveform data to a host computer for processing. In this paper, they present digital filtering algorithms for processing microcalorimeter pulses in real time at high count rates. The goal for these algorithms, which are being implemented in the readout electronics that they are also currently developing, is to achieve sufficiently good energy resolution for most applications while being (a) simple enough to be implemented in the readout electronics and (b) capable of processing overlapping pulses and thus achieving much higher output count rates than the rates that existing algorithms are currently achieving. Details of these algorithms are presented, and their performance was compared to that of the 'optimal filter' that is the dominant pulse processing algorithm in the cryogenic-detector community.

Rabin, Michael [Los Alamos National Laboratory; Hoover, Andrew S [Los Alamos National Laboratory; Bacrania, Mnesh K [Los Alamos National Laboratory; Tan, Hui [XIA-LLC; Breus, Dimitry [XIA-LLC; Henning, Wolfgang [XIA-LLC; Sabourov, Konstantin [XIA-LLC; Collins, Jeff [XAI-LLC; Warburton, William K [XIA-LLC; Dorise, Bertrand [NIST; Ullom, Joel N [NIST; [NON LANL

2009-01-01

85

Amplified Warming Rates in High Elevation Regions  

NASA Astrophysics Data System (ADS)

We use ground-based and satellite-retrieved observations in conjunction with output from global climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) to determine whether warming rates in high elevation regions are significantly different than in their lower elevation surroundings. In addition, for regions where there is enhanced warming at higher elevations, we investigate several of the potential mechanisms that may contribute to this enhancement. For the mid-latitudes in the Northern Hemisphere, the multi-model ensemble indicates that warming rates during the 21st century will be enhanced at high elevations relative to their lower elevation counterparts at the same latitude. This effect is most pronounced for daily minimum temperatures during the cold season in the Tibetan Plateau/Himalayan region. A neural network analysis is used to identify and quantify some of the potential mechanisms responsible for enhanced warming rates, including the effects of variables such as atmospheric water vapor, clouds, snow cover, and aerosols on the radiation and surface heat budgets. We also demonstrate that satellite retrievals can be used to expand the often sparse ground-based observations in such regions and that they provide the correct relationships between variables. Please fill in your abstract text.

Miller, James; Naud, Catherine; Chen, Yonghua; Ghatak, Debjani; Rangwala, Imtiaz; Sinsky, Eric

2014-05-01

86

Reproductive and behavioral abnormalities in tree swallows with high levels of PCB contamination  

SciTech Connect

Tree Swallows (Tachycineta bicolor) breeding along the Hudson River forage extensively on PCB contaminated insects that emerge from the river. The authors studied the reproductive ecology and behavior of tree swallows breeding at several sites along the Hudson River. These sites vary in the severity of PCB contamination. PCB levels in both eggs and chicks were found to be among the highest ever reported in this species, with concentrations comparable to those found in aquatic organisms in the Hudson River. In 1994 reproductive success at PCB contaminated sites was significantly impaired, relative to other sites in New York. Reduced reproductive success was largely attributed to high levels of nest abandonment during incubation and reduced hatchability of eggs. Growth and development of nestlings was not significantly impaired. Abnormal nest building behavior was also noted in 1994, and this was studied in detail in 1995. Nests from contaminated areas are significantly smaller than those at a nearby reference site and at other sites in New York. The authors suggest that the reduced reproductive outputs at these sites are, in large part, a result of effects on the behavior of incubating females. The population-level implications of these patterns are unknown.

McCarty, J. [Cornell Univ., Ithaca, NY (United States). Section of Ecology and Systematics; [Fish and Wildlife Service, Cortland, NY (United States); Secord, A. [Fish and Wildlife Service, Cortland, NY (United States); Tillitt, D. [National Biological Service, Columbia, MO (United States)

1995-12-31

87

High strain rate deformation of layered nanocomposites  

NASA Astrophysics Data System (ADS)

Insight into the mechanical behaviour of nanomaterials under the extreme condition of very high deformation rates and to very large strains is needed to provide improved understanding for the development of new protective materials. Applications include protection against bullets for body armour, micrometeorites for satellites, and high-speed particle impact for jet engine turbine blades. Here we use a microscopic ballistic test to report the responses of periodic glassy-rubbery layered block-copolymer nanostructures to impact from hypervelocity micron-sized silica spheres. Entire deformation fields are experimentally visualized at an exceptionally high resolution (below 10?nm) and we discover how the microstructure dissipates the impact energy via layer kinking, layer compression, extreme chain conformational flattening, domain fragmentation and segmental mixing to form a liquid phase. Orientation-dependent experiments show that the dissipation can be enhanced by 30% by proper orientation of the layers.

Lee, Jae-Hwang; Veysset, David; Singer, Jonathan P.; Retsch, Markus; Saini, Gagan; Pezeril, Thomas; Nelson, Keith A.; Thomas, Edwin L.

2012-11-01

88

High strain rate deformation of layered nanocomposites.  

PubMed

Insight into the mechanical behaviour of nanomaterials under the extreme condition of very high deformation rates and to very large strains is needed to provide improved understanding for the development of new protective materials. Applications include protection against bullets for body armour, micrometeorites for satellites, and high-speed particle impact for jet engine turbine blades. Here we use a microscopic ballistic test to report the responses of periodic glassy-rubbery layered block-copolymer nanostructures to impact from hypervelocity micron-sized silica spheres. Entire deformation fields are experimentally visualized at an exceptionally high resolution (below 10?nm) and we discover how the microstructure dissipates the impact energy via layer kinking, layer compression, extreme chain conformational flattening, domain fragmentation and segmental mixing to form a liquid phase. Orientation-dependent experiments show that the dissipation can be enhanced by 30% by proper orientation of the layers. PMID:23132014

Lee, Jae-Hwang; Veysset, David; Singer, Jonathan P; Retsch, Markus; Saini, Gagan; Pezeril, Thomas; Nelson, Keith A; Thomas, Edwin L

2012-01-01

89

High frame-rate digital radiographic videography  

SciTech Connect

High speed x-ray imaging can be an important tool for observing internal processes in a wide range of applications. In this paper we describe preliminary implementation of a system having the eventual goal of observing the internal dynamics of bone and joint reactions during loading. Two Los Alamos National Laboratory (LANL) gated and image intensified camera systems were used to record images from an x-ray image convertor tube to demonstrate the potential of high frame-rate digital radiographic videography in the analysis of bone and joint dynamics of the human body. Preliminary experiments were done at LANL to test the systems. Initial high frame-rate imaging (from 500 to 1000 frames/s) of a swinging pendulum mounted to the face of an X-ray image convertor tube demonstrated high contrast response and baseline sensitivity. The systems were then evaluated at the Motion Analysis Laboratory of Henry Ford Health Systems Bone and Joint Center. Imaging of a 9 inch acrylic disk with embedded lead markers rotating at approximately 1000 RPM, demonstrated the system response to a high velocity/high contrast target. By gating the P-20 phosphor image from the X-ray image convertor with a second image intensifier (II) and using a 100-microsecond wide optical gate through the second II, enough prompt light decay from the x-ray image convertor phosphor had taken place to achieve reduction of most of the motion blurring. Measurement of the marker velocity was made by using video frames acquired at 500 frames/s. The data obtained from both experiments successfully demonstrated the feasibility of the technique. Several key areas for improvement are discussed along with salient test results and experiment details.

King, N.S.P.; Cverna, F.H.; Albright, K.L.; Jaramillo, S.A.; Yates, G.J.; McDonald, T.E. [Los Alamos National Lab., NM (United States); Flynn, M.J.; Tashman, S. [Henry Ford Health System, Detroit, MI (United States)

1994-09-01

90

High resolution Ge/Li/ spectrometer reduces rate-dependent distortions at high counting rates  

NASA Technical Reports Server (NTRS)

Modified spectrometer system with a low-noise preamplifier reduces rate-dependent distortions at high counting rates, 25,000 counts per second. Pole-zero cancellation minimizes pulse undershoots due to multiple time constants, baseline restoration improves resolution and prevents spectral shifts.

Brenner, R.; Larsen, R. N.; Mann, H. M.; Rudnick, S. J.; Sherman, I. S.; Strauss, M. G.

1968-01-01

91

The adverse effects of high fat induced obesity on female reproductive cycle and hormones  

NASA Astrophysics Data System (ADS)

The prevalence of obesity, an established risk and progression factor for abnormal reproductive cycle and tissue damage in female mice. It leads to earlier puberty, menarche in young females and infertility. There are extensive range of consequences of obesity which includes type-2 diabetes, cardiovascular disease and insulin resistance. Obesity is the interaction between dietary intake, genes, life style and environment. The interplay of hormones estrogen, insulin, and leptin is well known on energy homeostasis and reproduction. The aim of this study is to determine the effect of high fat induced obesity on reproductive cycles and its hormonal abnormalities on mice model. Two week, 3 month and 8 month long normal (WT) and very high fat diet (VHFD) diet course is followed. When mice are fed with very high fat diet, there is a drastic increase in weight within the first week later. There was a significant (p<0.001) increase in leptin levels in 6 month VHFD treated animals. 2 week, 3 month and 6 month time interval pap smear test results showed number of cells, length of estrous cycle and phases of the estrous cycle changes with VHFD mice(n=30) compared to normal diet mice(n=10). These results also indicate that the changes in the reproductive cycles in VHFD treated female mice could be due to the changes in hormones. Histo-pathological analyses of kidney, ovary, liver, pancreas, heart and lungs showed remarkable changes in some tissue on exposure to very high fat. Highly deposited fat packets observed surrounding the hepatocytes and nerve cells.

Donthireddy, Laxminarasimha Reddy

92

High reproductive synchrony of Acropora (Anthozoa: Scleractinia) in the Gulf of Aqaba, Red Sea  

PubMed Central

Coral spawning in the northern Gulf of Aqaba has been reported to be asynchronous, making it almost unique when compared to other regions in the world. Here, we document the reproductive condition of Acropora corals in early June 2014 in Dahab, in the Gulf of Aqaba, 125 km south of previous studies conducted in Eilat, Israel. Seventy-eight percent of Acropora colonies from 14 species had mature eggs, indicating that most colonies will spawn on or around the June full moon, with a very high probability of multi-species synchronous spawning. Given the proximity to Eilat, we predict that a comparable sampling protocol would detect similar levels of reproductive synchrony throughout the Gulf of Aqaba consistent with the hypothesis that high levels of spawning synchrony are a feature of all speciose coral assemblages. PMID:25653848

Bouwmeester, Jessica; Berumen, Michael L.

2015-01-01

93

Cervix cancer brachytherapy: high dose rate.  

PubMed

Cervical cancer, although less common in industrialized countries, is the fourth most common cancer affecting women worldwide and the fourth leading cause of cancer death. In developing countries, these cancers are often discovered at a later stage in the form of locally advanced tumour with a poor prognosis. Depending on the stage of the disease, treatment is mainly based on a chemoradiotherapy followed by uterovaginal brachytherapy ending by a potential remaining tumour surgery or in principle for some teams. The role of irradiation is crucial to ensure a better local control. It has been shown that the more the delivered dose is important, the better the local results are. In order to preserve the maximum of organs at risk and to allow this dose escalation, brachytherapy (intracavitary and/or interstitial) has been progressively introduced. Its evolution and its progressive improvement have led to the development of high dose rate brachytherapy, the advantages of which are especially based on the possibility of outpatient treatment while maintaining the effectiveness of other brachytherapy forms (i.e., low dose rate or pulsed dose rate). Numerous innovations have also been completed in the field of imaging, leading to a progress in treatment planning systems by switching from two-dimensional form to a three-dimensional one. Image-guided brachytherapy allows more precise target volume delineation as well as an optimized dosimetry permitting a better coverage of target volumes. PMID:25151650

Miglierini, P; Malhaire, J-P; Goasduff, G; Miranda, O; Pradier, O

2014-10-01

94

High-Rate Digital Receiver Board  

NASA Technical Reports Server (NTRS)

A high-rate digital receiver (HRDR) implemented as a peripheral component interface (PCI) board has been developed as a prototype of compact, general-purpose, inexpensive, potentially mass-producible data-acquisition interfaces between telemetry systems and personal computers. The installation of this board in a personal computer together with an analog preprocessor enables the computer to function as a versatile, highrate telemetry-data-acquisition and demodulator system. The prototype HRDR PCI board can handle data at rates as high as 600 megabits per second, in a variety of telemetry formats, transmitted by diverse phase-modulation schemes that include binary phase-shift keying and various forms of quadrature phaseshift keying. Costing less than $25,000 (as of year 2003), the prototype HRDR PCI board supplants multiple racks of older equipment that, when new, cost over $500,000. Just as the development of standard network-interface chips has contributed to the proliferation of networked computers, it is anticipated that the development of standard chips based on the HRDR could contribute to reductions in size and cost and increases in performance of telemetry systems.

Ghuman, Parminder; Bialas, Thomas; Brambora, Clifford; Fisher, David

2004-01-01

95

High dose rate brachytherapy for oral cancer  

PubMed Central

Brachytherapy results in better dose distribution compared with other treatments because of steep dose reduction in the surrounding normal tissues. Excellent local control rates and acceptable side effects have been demonstrated with brachytherapy as a sole treatment modality, a postoperative method, and a method of reirradiation. Low-dose-rate (LDR) brachytherapy has been employed worldwide for its superior outcome. With the advent of technology, high-dose-rate (HDR) brachytherapy has enabled health care providers to avoid radiation exposure. This therapy has been used for treating many types of cancer such as gynecological cancer, breast cancer, and prostate cancer. However, LDR and pulsed-dose-rate interstitial brachytherapies have been mainstays for head and neck cancer. HDR brachytherapy has not become widely used in the radiotherapy community for treating head and neck cancer because of lack of experience and biological concerns. On the other hand, because HDR brachytherapy is less time-consuming, treatment can occasionally be administered on an outpatient basis. For the convenience and safety of patients and medical staff, HDR brachytherapy should be explored. To enhance the role of this therapy in treatment of head and neck lesions, we have reviewed its outcomes with oral cancer, including Phase I/II to Phase III studies, evaluating this technique in terms of safety and efficacy. In particular, our studies have shown that superficial tumors can be treated using a non-invasive mold technique on an outpatient basis without adverse reactions. The next generation of image-guided brachytherapy using HDR has been discussed. In conclusion, although concrete evidence is yet to be produced with a sophisticated study in a reproducible manner, HDR brachytherapy remains an important option for treatment of oral cancer. PMID:23179377

YamazakI, Hideya; Yoshida, Ken; Yoshioka, Yasuo; Shimizutani, Kimishige; Furukawa, Souhei; Koizumi, Masahiko; Ogawa, Kazuhiko

2013-01-01

96

A. Michele Arntz Evan H. DeLucia Nicholas Jordan Contribution of photosynthetic rate to growth and reproduction  

E-print Network

and reproduction in Amaranthus hybridus Received: 27 March 1998 / Accepted: 28 August 1998 Abstract While to reproduction through eects on growth, we compared wild-type Amaranthus hybridus families to those with a single

DeLucia, Evan H.

97

Image-guided high dose rate endorectal brachytherapy  

SciTech Connect

Fractionated high dose rate endorectal brachytherapy (HDR-EBT) using CT-based treatment planning is an alternative method for preoperative down-sizing and down-staging of advanced rectal adeno-carcinomas. The authors present an image guidance procedure that was developed to ensure daily dose reproducibility for the four brachytherapy treatment fractions. Since the applicator might not be placed before each treatment fraction inside the rectal lumen in the same manner as it was placed during the 3D CT volume acquisition used for treatment planning, there is a shift along the catheter axis that may have to be performed. The required shift is determined by comparison of a daily radiograph with the treatment planning digitally-reconstructed radiograph (DRR). A procedure is developed for DRR reconstruction from the 3D data set used for the treatment planning, and two possible daily longitudinal shifts are illustrated: above and below the planning dose distribution. The authors also describe the procedure for rotational alignment illustrated on a clinical case. Reproduction of the treatment planned dose distribution on a daily basis is crucial for the success of fractionated 3D based brachytherapy treatments. Due to the cylindrical symmetry of the applicator used for preoperative HDR-EBT, two types of adjustments are necessary: applicator rotation and dwell position shift along the applicator's longitudinal axis. The impact of the longitudinal applicator shift prior to treatment delivery for 62 patients treated in our institution is also assessed.

Devic, Slobodan; Vuong, Te; Moftah, Belal; Evans, Michael; Podgorsak, Ervin B.; Poon, Emily; Verhaegen, Frank [Department of Medical Physics, McGill University Health Centre, Montreal, Quebec, H3G 1A4 (Canada); Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec, H3G 1A4 (Canada); Department of Medical Physics, McGill University Health Centre, Montreal, Quebec, H3G 1A4 (Canada)

2007-11-15

98

Application of high-rate cutting tools  

NASA Astrophysics Data System (ADS)

Widespread application of the newest high-rate cutting tools to the most appropriate jobs is slowed by the sheer magnitude of developments in tool types, materials, workpiece applications, and by the rapid pace of change. Therefore, a study of finishing and roughing sizes of coated carbide inserts having a variety of geometries for single point turning was completed. The cutting tools were tested for tool life, chip quality, and workpiece surface finish at various cutting conditions with medium alloy steel. An empirical wear-life data base was established, and a computer program was developed to facilitate technology transfer, assist selection of carbide insert grades, and provide machine operating parameters. A follow-on test program was implemented suitable for next generation coated carbides, rotary cutting tools, cutting fluids, and ceramic tool materials.

Moriarty, John L., Jr.

1989-03-01

99

Consideration of wear rates at high velocity  

NASA Astrophysics Data System (ADS)

The development of the research presented here is one in which high velocity relative sliding motion between two bodies in contact has been considered. Overall, the wear environment is truly three-dimensional. The attempt to characterize three-dimensional wear was not economically feasible because it must be analyzed at the micro-mechanical level to get results. Thus, an engineering approximation was carried out. This approximation was based on a metallographic study identifying the need to include viscoplasticity constitutive material models, coefficient of friction, relationships between the normal load and velocity, and the need to understand wave propagation. A sled test run at the Holloman High Speed Test Track (HHSTT) was considered for the determination of high velocity wear rates. In order to adequately characterize high velocity wear, it was necessary to formulate a numerical model that contained all of the physical events present. The experimental results of a VascoMax 300 maraging steel slipper sliding on an AISI 1080 steel rail during a January 2008 sled test mission were analyzed. During this rocket sled test, the slipper traveled 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s. This type of environment was never considered previously in terms of wear evaluation. Each of the features of the metallography were obtained through micro-mechanical experimental techniques. The byproduct of this analysis is that it is now possible to formulate a model that contains viscoplasticity, asperity collisions, temperature and frictional features. Based on the observations of the metallographic analysis, these necessary features have been included in the numerical model, which makes use of a time-dynamic program which follows the movement of a slipper during its experimental test run. The resulting velocity and pressure functions of time have been implemented in the explicit finite element code, ABAQUS. Two-dimensional, plane strain models were used to determine the state of stress within the slipper and the pressure distribution along the bottom. Local submodel collisions between the slipper and a 6 mum radius hemispherical asperity were analyzed to determine mechanical and melt wear rates. A simplified damage criterion of maximum Mises stress was used to determine the damaged volume during the slipper and asperity collision. Overall, the model predicts a total wear volume that is approximately 36% of the total wear measured during the metallographic analysis.

Hale, Chad S.

100

Differential reproductive success favours strong host preference in a highly specialized brood parasite.  

PubMed

Obligate avian brood parasites show dramatic variation in the degree to which they are host specialists or host generalists. The screaming cowbird Molothrus rufoaxillaris is one of the most specialized brood parasites, using a single host, the bay-winged cowbird (Agelaioides badius) over most of its range. Coevolutionary theory predicts increasing host specificity the longer the parasite interacts with a particular avian community, as hosts evolve defences that the parasite cannot counteract. According to this view, host specificity can be maintained if screaming cowbirds avoid parasitizing potentially suitable hosts that have developed effective defences against parasitic females or eggs. Specialization may also be favoured, even in the absence of host defences, if the parasite's reproductive success in alternative hosts is lower than that in the main host. We experimentally tested these hypotheses using as alternative hosts two suitable but unparasitized species: house wrens (Troglodytes aedon) and chalk-browed mockingbirds (Mimus saturninus). We assessed host defences against parasitic females and eggs, and reproductive success of the parasite in current and alternative hosts. Alternative hosts did not discriminate against screaming cowbird females or eggs. Egg survival and hatching success were similarly high in current and alternative hosts, but the survival of parasitic chicks was significantly lower in alternative hosts. Our results indicate that screaming cowbirds have the potential to colonize novel hosts, but higher reproductive success in the current host may favour host fidelity. PMID:18647716

De Mársico, María C; Reboreda, Juan C

2008-11-01

101

Differential reproductive success favours strong host preference in a highly specialized brood parasite  

PubMed Central

Obligate avian brood parasites show dramatic variation in the degree to which they are host specialists or host generalists. The screaming cowbird Molothrus rufoaxillaris is one of the most specialized brood parasites, using a single host, the bay-winged cowbird (Agelaioides badius) over most of its range. Coevolutionary theory predicts increasing host specificity the longer the parasite interacts with a particular avian community, as hosts evolve defences that the parasite cannot counteract. According to this view, host specificity can be maintained if screaming cowbirds avoid parasitizing potentially suitable hosts that have developed effective defences against parasitic females or eggs. Specialization may also be favoured, even in the absence of host defences, if the parasite's reproductive success in alternative hosts is lower than that in the main host. We experimentally tested these hypotheses using as alternative hosts two suitable but unparasitized species: house wrens (Troglodytes aedon) and chalk-browed mockingbirds (Mimus saturninus). We assessed host defences against parasitic females and eggs, and reproductive success of the parasite in current and alternative hosts. Alternative hosts did not discriminate against screaming cowbird females or eggs. Egg survival and hatching success were similarly high in current and alternative hosts, but the survival of parasitic chicks was significantly lower in alternative hosts. Our results indicate that screaming cowbirds have the potential to colonize novel hosts, but higher reproductive success in the current host may favour host fidelity. PMID:18647716

De Mársico, María C; Reboreda, Juan C

2008-01-01

102

High-speed Viterbi decoding of high-rate codes  

NASA Astrophysics Data System (ADS)

This paper analyzes the problems of implementing high-speed Viterbi decoding and demonstrates that practical 120-Mbit/s digital decoders of moderate complexity can be built with currently available emitter-coupled logic. The results are generally applicable to a variety of high-speed applications, although specific details are based upon rate 2/3 codes for use with 8-PSK modulation. Metric computation is simplified by demodulating each 8-phase symbol into quadrature I and Q components, rather than three separate output channels.

Snyder, J. S.

103

Potential and realized rates of vegetative reproduction in Spirodela polyrhiza, Lemna minor, and Wolffia borealis  

Microsoft Academic Search

The rate of vegetative propagule development was estimated in three duckweed (Lemnaceae) species, Spirodela polyrhiza, Lemna minor, and Wolffia borealis, by measuring the number of daughter fronds produced over the life span of mother fronds. Under the same constant environmental conditions, plants of L. minor lived the longest (31.3 days) and produced the most daughter fronds (14.0), yet W. borealis

Gordon D. Lemon; Usher Posluszny; Brian C. Husband

2001-01-01

104

High resolution, high rate x-ray spectrometer  

DOEpatents

It is an object of the invention to provide a pulse processing system for use with detected signals of a wide dynamic range which is capable of very high counting rates, with high throughput, with excellent energy resolution and a high signal-to-noise ratio. It is a further object to provide a pulse processing system wherein the fast channel resolving time is quite short and substantially independent of the energy of the detected signals. Another object is to provide a pulse processing system having a pile-up rejector circuit which will allow the maximum number of non-interfering pulses to be passed to the output. It is also an object of the invention to provide new methods for generating substantially symmetrically triangular pulses for use in both the main and fast channels of a pulse processing system.

Goulding, F.S.; Landis, D.A.

1983-07-14

105

Linking Reproduction and Survival Can Improve Model Estimates of Vital Rates Derived from Limited Time-Series Counts of Pinnipeds and Other Species  

PubMed Central

We propose a method to model the physiological link between somatic survival and reproductive output that reduces the number of parameters that need to be estimated by models designed to determine combinations of birth and death rates that produce historic counts of animal populations. We applied our Reproduction and Somatic Survival Linked (RSSL) method to the population counts of three species of North Pacific pinnipeds (harbor seals, Phoca vitulina richardii (Gray, 1864); northern fur seals, Callorhinus ursinus (L., 1758); and Steller sea lions, Eumetopias jubatus (Schreber, 1776))—and found our model outperformed traditional models when fitting vital rates to common types of limited datasets, such as those from counts of pups and adults. However, our model did not perform as well when these basic counts of animals were augmented with additional observations of ratios of juveniles to total non-pups. In this case, the failure of the ratios to improve model performance may indicate that the relationship between survival and reproduction is redefined or disassociated as populations change over time or that the ratio of juveniles to total non-pups is not a meaningful index of vital rates. Overall, our RSSL models show advantages to linking survival and reproduction within models to estimate the vital rates of pinnipeds and other species that have limited time-series of counts. PMID:24324541

Battaile, Brian C.; Trites, Andrew W.

2013-01-01

106

Bipolar high-repetition-rate high-voltage nanosecond pulser  

SciTech Connect

The pulser designed is mainly used for producing corona plasma in waste water treatment system. Also its application in study of dielectric electrical properties will be discussed. The pulser consists of a variable dc power source for high-voltage supply, two graded capacitors for energy storage, and the rotating spark gap switch. The key part is the multielectrode rotating spark gap switch (MER-SGS), which can ensure wider range modulation of pulse repetition rate, longer pulse width, shorter pulse rise time, remarkable electrical field distortion, and greatly favors recovery of the gap insulation strength, insulation design, the life of the switch, etc. The voltage of the output pulses switched by the MER-SGS is in the order of 3-50 kV with pulse rise time of less than 10 ns and pulse repetition rate of 1-3 kHz. An energy of 1.25-125 J per pulse and an average power of up to 10-50 kW are attainable. The highest pulse repetition rate is determined by the driver motor revolution and the electrode number of MER-SGS. Even higher voltage and energy can be switched by adjusting the gas pressure or employing N{sub 2} as the insulation gas or enlarging the size of MER-SGS to guarantee enough insulation level.

Tian Fuqiang; Wang Yi; Shi Hongsheng [School of Electrical Engineer, Beijing Jiaotong University, Beijing 100044 (China); Lei Qingquan [School of Electrical Engineer, Beijing Jiaotong University, Beijing 100044 (China); School of Electrical and Electronic Engineer, Harbin University of Science and Technology, Harbin 150040 (China); Key Laboratory of Engineer Dielectrics and Its Application of Education Ministry, Harbin 150040 (China)

2008-06-15

107

Tradeoff between offspring mass and subsequent reproduction in a highly iteroparous mammal  

E-print Network

subsequent reproductive success or survival. We used longitudinal data on marked mountain goatsOreamnos americanus to assess if offspring mass at weaning affected maternal survival and future reproduction

Festa-Bianchet, Marco

108

Cheetah: A high frame rate, high resolution SWIR image camera  

NASA Astrophysics Data System (ADS)

A high resolution, high frame rate InGaAs based image sensor and associated camera has been developed. The sensor and the camera are capable of recording and delivering more than 1700 full 640x512pixel frames per second. The FPA utilizes a low lag CTIA current integrator in each pixel, enabling integration times shorter than one microsecond. On-chip logics allows for four different sub windows to be read out simultaneously at even higher rates. The spectral sensitivity of the FPA is situated in the SWIR range [0.9-1.7 ?m] and can be further extended into the Visible and NIR range. The Cheetah camera has max 16 GB of on-board memory to store the acquired images and transfer the data over a Gigabit Ethernet connection to the PC. The camera is also equipped with a full CameralinkTM interface to directly stream the data to a frame grabber or dedicated image processing unit. The Cheetah camera is completely under software control.

Neys, Joel; Bentell, Jonas; O'Grady, Matt; Vermeiren, Jan; Colin, Thierry; Hooylaerts, Peter; Grietens, Bob

2008-10-01

109

HIgh Rate X-ray Fluorescence Detector  

SciTech Connect

The purpose of this project was to develop a compact, modular multi-channel x-ray detector with integrated electronics. This detector, based upon emerging silicon drift detector (SDD) technology, will be capable of high data rate operation superior to the current state of the art offered by high purity germanium (HPGe) detectors, without the need for liquid nitrogen. In addition, by integrating the processing electronics inside the detector housing, the detector performance will be much less affected by the typically noisy electrical environment of a synchrotron hutch, and will also be much more compact than current systems, which can include a detector involving a large LN2 dewar and multiple racks of electronics. The combined detector/processor system is designed to match or exceed the performance and features of currently available detector systems, at a lower cost and with more ease of use due to the small size of the detector. In addition, the detector system is designed to be modular, so a small system might just have one detector module, while a larger system can have many â?? you can start with one detector module, and add more as needs grow and budget allows. The modular nature also serves to simplify repair. In large part, we were successful in achieving our goals. We did develop a very high performance, large area multi-channel SDD detector, packaged with all associated electronics, which is easy to use and requires minimal external support (a simple power supply module and a closed-loop water cooling system). However, we did fall short of some of our stated goals. We had intended to base the detector on modular, large-area detectors from Ketek GmbH in Munich, Germany; however, these were not available in a suitable time frame for this project, so we worked instead with pnDetector GmbH (also located in Munich). They were able to provide a front-end detector module with six 100 m^2 SDD detectors (two monolithic arrays of three elements each) along with associated preamplifiers; these detectors surpassed the performance we expected to get from the Ketek detectors, however they are housed in a sealed module, which does not offer the ease of repair and expandability weâ??d hoped to achieve with the Ketek SDDâ??s. Our packaging efforts were quite successful, as we came up with a very compact way to mount the detector and to house the associated electronics, as well as a very effective way to reliably take out the heat (from the electronics as well as the detectorâ??s Peltier coolers) without risk of condensation and without external airflow or vibration, which could create problems for the target applications. While we were able to design compact processing electronics that fit into the detector assembly, they are still at the prototype stage, and would require a significant redesign to achieve product status. We have not yet tested this detector at a synchrotron facility; we do still plan on working with some close contacts at the nearby Stanford Synchrotron Radiation Laboratory (SSRL) to get some testing with the beam (using existing commercial electronics for readout, as the integrated processor is not ready for use).

Grudberg, Peter Matthew [XIA LLC

2013-04-30

110

Detection and Typing of Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus by Multiplex Real-Time RT-PCR  

Microsoft Academic Search

Porcine reproductive and respiratory syndrome (PRRS) causes economic losses in the pig industry worldwide, and PRRS viruses (PRRSV) are classified into the two distinct genotypes “North American (NA, type 2)” and “European (EU, type 1)”. In 2006, a highly pathogenic NA strain of PRRSV (HP-PRRSV), characterized by high fever as well as high morbidity and mortality, emerged in swine farms

Kerstin Wernike; Bernd Hoffmann; Malte Dauber; Elke Lange; Horst Schirrmeier; Martin Beer

2012-01-01

111

A three generation reproduction study with Sprague-Dawley rats consuming high-amylose transgenic rice.  

PubMed

The transgenic rice line (TRS) enriched with amylose and resistant starch (RS) was developed by antisense RNA inhibition of starch-branching enzymes. Cereal starch with high amylose has a great benefit on human health through its resistant starch. In order to evaluate the effect of transgenic rice on rats, the rats were fed diets containing 70% TRS rice flour, its near-isogenic rice flour or the standard diet as the control through three generations. In the present study, clinical performance, reproductive capacity and pathological responses including body weight, food consumption, reproductive data, hematological parameters, serum chemistry components, organ relative weights and histopathology were examined. Some statistically significant differences were observed in rats consuming the high amylose rice diet when compared to rats fed the near-isogenic control rice diet or the conventional (non-rice) standard diet. These differences were generally of small magnitude, appeared to be random in nature, and were within normal limits for the strain of rat used, and were therefore not considered to be biologically meaningful or treatment related. PMID:25194626

Zhou, Xing Hua; Dong, Ying; Zhao, Yan Sheng; Xiao, Xiang; Wang, Yun; He, Yuan Qing; Liu, Qiao Quan

2014-12-01

112

High Strain Rate Compressive Tests on Woven Graphite Epoxy Composites  

Microsoft Academic Search

The behavior of composite materials may be different when they are subjected to high strain rate load. Penetrating split Hopkinson pressure bar (P-SHPB) is a method to impose high strain rate on specimen in the laboratory experiments. This research work studied the response of the thin circular shape specimens, made out of woven graphite epoxy composites, to high strain rate

Mohammad Reza Allazadeh; Sylvanus N. Wosu

2011-01-01

113

Effects of folic acid and vitamin B12 supplementation on culling rate, diseases, and reproduction in commercial dairy herds.  

PubMed

This study was undertaken to determine the effect of a combined folic acid and vitamin B12 supplement given in early lactation on culling rate, metabolic disorders and other diseases, and reproduction in commercial dairy herds. A total of 805 cows (271 primiparous and 534 multiparous cows) in 15 commercial dairy herds were involved. Every 2mo from February to December 2010 and within each herd, cows were assigned according to parity, previous 305-d milk production, and calving interval to 5mL of either (1) saline 0.9% NaCl (control group) or (2) 320mg of folic acid + 10mg of vitamin B12 (vitamin group). Treatments were administered weekly by intramuscular injections starting 3wk before the expected calving date until 8wk after parturition. A total of 221 cows were culled before the next dry period. Culling rate was not affected by treatment and was 27.5%; culling rate was greater for multiparous (32.2%) than for primiparous cows (18.8%). Within the first 60d in milk (DIM), 47 cows were culled, representing 21.3% of total culling, and no treatment effect was noted. Ketosis incidence based on a threshold ?100µmol/L of ?-hydroxybutyrate in milk was 38.3±2.9% for the vitamin group and 41.8±3.0% for the control group and was not affected by treatment. The combined supplement of folic acid and vitamin B12 did not decrease incidence of retained placenta, displaced abomasum, milk fever, metritis, or mastitis. However, the incidence of dystocia decreased by 50% in multiparous cows receiving the vitamin supplement, although no effect was observed in primiparous cows. The first breeding postpartum for multiparous cows occurred 3.8d earlier with the vitamin supplement compared with controls, whereas no treatment effect was seen for primiparous cows. Days open, first- and second-breeding conception rates, number of breedings per conception, and percentage of cows pregnant at 150 DIM were not affected by treatment. The reduced percentage of dystocia combined with the earlier DIM at first breeding for multiparous cows receiving the combined supplementation in folic acid and vitamin B12 indicates that the vitamin supplement had a positive effect in older cows. PMID:24485680

Duplessis, M; Girard, C L; Santschi, D E; Laforest, J-P; Durocher, J; Pellerin, D

2014-04-01

114

High strain rate failure of Armco iron  

NASA Astrophysics Data System (ADS)

Using the planar impact technique together with a VISAR laser interferometer, failure of Armco iron under dynamic loading was investigated. Spall strength and incipient increase of damage were evaluated from measured wave profiles. These were compared with microscopic damage which showed to be in good agreement with the above mentioned macroscopic damage. Spall strength was independent from loading stress and microscopic features like grain size or twin density but dependent on a macroscopically defined spall strain rate.

Arnold, W.

1994-07-01

115

High rate acoustic link for underwater video transmission  

Microsoft Academic Search

A high bit rate acoustic link for video transmission over an underwater channel is investigated. The key to achieving this objective lies in two approaches: use of efficient data compression algorithms and use of high-level bandwidth-efficient modulation methods. Currently available video encoding standards allow video transmission at bit rates as low as 64 kbps. While this rate is still above

Costas Pelekanakis; Milica Stojanovic; Lee Freitag

2003-01-01

116

ISAP 2012 Brosseaud et al: High modulus asphalt with high rate of recycling 1/13 High modulus asphalt mixes with high rate of RA: what does  

E-print Network

ISAP 2012 Brosseaud et al: High modulus asphalt with high rate of recycling 1/13 High modulus asphalt mixes with high rate of RA: what does it happen? Yves Brosseaud, French Institute of Science Module Elevé (EME - High Modulus Asphalt mixes, in english) give, since more than 20 years, an excellent

Paris-Sud XI, Université de

117

Reproductive parameters and oxidative stress status of male rats fed with low and high salt diet  

PubMed Central

BACKGROUND: Deficiency of minerals and micronutrients has been reported to impair the process of spermatogenesis. Historically, salt has been used by women on their husbands to increase their libido, however, the role of salt diet on sperm parameters are yet to be ascertained. AIM: The present study was designed to determine the effect of low and high salt diet on sperm parameters, oxidative status and reproductive hormone levels of male rats. MATERIALS AND METHODS: A total of 18 rats were divided into three groups: Group I: (control) received 0.3% salt diet, Group II: low salt (received 0.14% salt diet) and Group III: high salt (received 8% salt diet). All animals were treated for 6 weeks; after which epididymal sperm parameters; oxidative stress markers (malondialdehyde, glutathione, catalase and superoxide dismutase) in the testes and epididymal tissues, as well as follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone levels were determined. RESULTS: The results showed decreased sperm count in the low salt diet rats while increased sperm count was observed in the high salt diet treated rats. Both low salt and high salt diet fed rats exhibited increased abnormal sperm cells and increased epididymal oxidative stress when compared with their respective control. FSH and testosterone levels were increased in the high salt fed rats while LH level was decreased when compared with the control values. CONCLUSION: This study suggests that both low and high salt diet play a negative role in the fertility of male rats. PMID:24672168

Iranloye, Bolanle O.; Oludare, Gabriel O.; Morakinyo, Ayodele O.; Esume, Naomi A.; Ekeh, Lucy C.

2013-01-01

118

Dose rate in brachytherapy using after-loading machine: pulsed or high-dose rate?  

PubMed

Since February 2014, it is no longer possible to use low-dose rate 192 iridium wires due to the end of industrial production of IRF1 and IRF2 sources. The Brachytherapy Group of the French society of radiation oncology (GC-SFRO) has recommended switching from iridium wires to after-loading machines. Two types of after-loading machines are currently available, based on the dose rate used: pulsed-dose rate or high-dose rate. In this article, we propose a comparative analysis between pulsed-dose rate and high-dose rate brachytherapy, based on biological, technological, organizational and financial considerations. PMID:25195117

Hannoun-Lévi, J-M; Peiffert, D

2014-10-01

119

High performance interconnection between high data rate networks  

NASA Technical Reports Server (NTRS)

The bridge/gateway system needed to interconnect a wide range of computer networks to support a wide range of user quality-of-service requirements is discussed. The bridge/gateway must handle a wide range of message types including synchronous and asynchronous traffic, large, bursty messages, short, self-contained messages, time critical messages, etc. It is shown that messages can be classified into three basic classes, synchronous and large and small asynchronous messages. The first two require call setup so that packet identification, buffer handling, etc. can be supported in the bridge/gateway. Identification enables resequences in packet size. The third class is for messages which do not require call setup. Resequencing hardware based to handle two types of resequencing problems is presented. The first is for a virtual parallel circuit which can scramble channel bytes. The second system is effective in handling both synchronous and asynchronous traffic between networks with highly differing packet sizes and data rates. The two other major needs for the bridge/gateway are congestion and error control. A dynamic, lossless congestion control scheme which can easily support effective error correction is presented. Results indicate that the congestion control scheme provides close to optimal capacity under congested conditions. Under conditions where error may develop due to intervening networks which are not lossless, intermediate error recovery and correction takes 1/3 less time than equivalent end-to-end error correction under similar conditions.

Foudriat, E. C.; Maly, K.; Overstreet, C. M.; Zhang, L.; Sun, W.

1992-01-01

120

Testing and modeling high strain rate behavior of polymeric composites  

Microsoft Academic Search

The present study was aimed at modeling the high strain rate response of the unidirectional S2Glass\\/8553-40 polymeric composite material system. High strain rate experiments were conducted on a split Hopkinson pressure bar (SHPB), on balanced symmetric laminates from which the stress, strain and strain rate histories within the laminates were recovered. Strain rates of the order of 1000\\/s were achieved

Srikanth V. Thiruppukuzhi; C. T. Sun

1998-01-01

121

High rates of nonbreeding adult bald eagles in southeastern Alaska  

SciTech Connect

Present knowledge of bald eagle (Haliaeetus leucocephalus) demography is derived primarily from populations in environments that have been drastically altered by man. Most reproductive studies were done in the 1960's and 1970's when chemical toxins were inhibiting bald eagle productivity. Earlier, the removal of old-growth forests and decimation of anadromous fish runs by Euro-Americans may have greatly reduced bald eagle abundance from presettlement levels. Historical trends in this species are of interest because fundamental differences may exist between populations in pristine and man-altered environments. One difference may be breeding rate. Surpluses of nonbreeding adult bald eagles during the nesting season are rarely mentioned in the literature. Most surveys of reproductive success focus exclusively on eagles at nest sites, which assumes nearly all adults attempt to breed each year. The authors report that a majority of adults in the relatively pristine habitats of southeastern Alaska do not breed annually. This finding is important because if surpluses of non-breeding adults are a natural feature of the population, then hypotheses on density dependent population regulation and the evolution of delayed maturation are suggested. If, on the other hand, the abundance of nonbreeders is an artifact of recent environmental perturbations, serious population declines may occur in southeastern Alaska.

Hansen, A.J.; Hodges, J.I. Jr.

1985-01-01

122

Emergence and pathogenicity of highly pathogenic Porcine reproductive and respiratory syndrome virus in Vientiane, Lao People's Democratic Republic.  

PubMed

Highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) characterized by high fever, high morbidity, and high mortality in pigs of all ages emerged in China in 2006 and spread rapidly throughout Southeast Asia. In July 2010, a highly contagious swine disease with clinical signs similar to those of HP-PRRS was observed in the Lao People's Democratic Republic (Lao PDR). A field investigation covering 8 pig farms and 1 slaughterhouse in 7 different districts in the capital city of Vientiane was conducted to identify the disease. Total mortality rates ranged from 6.02% in boars to 91.28% in piglets (mean 54.15%) across the farms investigated. Emergence of the HP-PRRS virus (HP-PRRSV) in Lao PDR was confirmed using real-time reverse transcription polymerase chain reaction as well as virus isolation and identification. An animal inoculation study was performed to characterize the HP-PRRSV responsible for this outbreak. Isolate Laos 1.13 was inoculated into 70-day-old specific pathogen-free pigs to study pathogenicity. Clinical signs of high fever, rubefaction, respiratory distress, nervous symptoms, and diarrhea were observed in inoculated pigs, as well as pathological hemorrhagic lesions consolidated in the lungs. Morbidity and mortality were 100% and 60%, respectively, in inoculated pigs. HP-PRRSV was re-isolated from the inoculated pigs. Results suggested that the newly emerged HP-PRRSV was responsible for recent outbreaks of the swine disease in Lao PDR. The current report highlights the importance of continuous surveillance in neighboring countries to prevent introduction of PRRS to new regions. PMID:22379051

Ni, Jianqiang; Yang, Shibiao; Bounlom, Douangngeun; Yu, Xiuling; Zhou, Zhi; Song, Jianling; Khamphouth, Vongxay; Vatthana, Theppannga; Tian, Kegong

2012-03-01

123

High-Rate Strong-Signal Quantum Cryptography  

NASA Technical Reports Server (NTRS)

Several quantum cryptosystems utilizing different kinds of nonclassical lights, which can accommodate high intensity fields and high data rate, are described. However, they are all sensitive to loss and both the high rate and the strong-signal character rapidly disappear. A squeezed light homodyne detection scheme is proposed which, with present-day technology, leads to more than two orders of magnitude data rate improvement over other current experimental systems for moderate loss.

Yuen, Horace P.

1996-01-01

124

High Strain Rate Compressive Tests on Woven Graphite Epoxy Composites  

Microsoft Academic Search

The behavior of composite materials may be different when they are subjected to high strain rate load. Penetrating split Hopkinson\\u000a pressure bar (P-SHPB) is a method to impose high strain rate on specimen in the laboratory experiments. This research work\\u000a studied the response of the thin circular shape specimens, made out of woven graphite epoxy composites, to high strain rate

Mohammad Reza Allazadeh; Sylvanus N. Wosu

2011-01-01

125

Coded Acquisition of High Frame Rate Video  

NASA Astrophysics Data System (ADS)

High frame video (HFV) is an important investigational tool in sciences, engineering and military. In ultra-high speed imaging, the obtainable temporal, spatial and spectral resolutions are limited by the sustainable throughput of in-camera mass memory, the lower bound of exposure time, and illumination conditions. In order to break these bottlenecks, we propose a new coded video acquisition framework that employs K > 2 conventional cameras, each of which makes random measurements of the 3D video signal in both temporal and spatial domains. For each of the K cameras, this multi-camera strategy greatly relaxes the stringent requirements in memory speed, shutter speed, and illumination strength. The recovery of HFV from these random measurements is posed and solved as a large scale l1 minimization problem by exploiting joint temporal and spatial sparsities of the 3D signal. Three coded video acquisition techniques of varied trade offs between performance and hardware complexity are developed: frame-wise coded acquisition, pixel-wise coded acquisition, and column-row-wise coded acquisition. The performances of these techniques are analyzed in relation to the sparsity of the underlying video signal. Simulations of these new HFV capture techniques are carried out and experimental results are reported.

Pournaghi, Reza; Wu, Xiaolin

2014-12-01

126

Infection of United States swine with a Chinese highly pathogenic strain of porcine reproductive and respiratory syndrome virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

To assess the pathogenic effects of Type 2 highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) on healthy 10-week old commercial swine in the United States, viral kinetics and resultant disease caused by intranasal inoculation of such virus rescued from an infectious clo...

127

The vOTU domain of highly-pathogenic porcine reproductive and respiratory syndrome virus displays a differential substrate preference  

Technology Transfer Automated Retrieval System (TEKTRAN)

Arterivirus genus member Porcine reproductive and respiratory syndrome virus (PRRSV) causes an economically devastating disease that presents global concerns to the pork industry, which have been exacerbated by the emergence of a highly pathogenic PRRSV strain (HP-PRRSV) in China and Southeast Asia....

128

HIGH-THROUGHPUT CELLULAR ASSAYS FOR MODELING TOXICITY IN THE FISH REPRODUCTIVE SYSTEM  

EPA Science Inventory

The most important benefit of this project is the experimental evaluation of all essential steps in the development and testing of adverse outcome pathways (AOP) for a diverse set of reproductive and non-reproductive toxicants. In contrast to human testing and the toxicity pat...

129

High data rate optical transceiver terminal  

NASA Technical Reports Server (NTRS)

The objectives of this study were: (1) to design a 400 Mbps optical transceiver terminal to operate from a high-altitude balloon-borne platform in order to permit the quantitative evaluation of a space-qualifiable optical communications system design, (2) to design an atmospheric propagation experiment to operate in conjunction with the terminal to measure the degrading effects of the atmosphere on the links, and (3) to design typical optical communications experiments for space-borne laboratories in the 1980-1990 time frame. As a result of the study, a transceiver package has been configured for demonstration flights during late 1974. The transceiver contains a 400 Mbps transmitter, a 400 Mbps receiver, and acquisition and tracking receivers. The transmitter is a Nd:YAG, 200 Mhz, mode-locked, CW, diode-pumped laser operating at 1.06 um requiring 50 mW for 6 db margin. It will be designed to implement Pulse Quaternary Modulation (PQM). The 400 Mbps receiver utilizes a Dynamic Crossed-Field Photomultiplier (DCFP) detector. The acquisition receiver is a Quadrant Photomultiplier Tube (QPMT) and receives a 400 Mbps signal chopped at 0.1 Mhz.

Clarke, E. S.

1973-01-01

130

High strain rate compressive behaviour of aluminium alloy foams  

Microsoft Academic Search

The high strain rate compressive behaviour of two cellular aluminium alloys (Alulight and Duocel) has been investigated using the split Hopkinson pressure bar and direct impact tests. It is found that the dynamic behaviour of these foams is very similar to their quasi-static behaviour. The plateau stress is almost insensitive to strain rate, for strain rates ?? up to 5000s?1.

V. S. Deshpande; N. A. Fleck

2000-01-01

131

Reproductive success and failure: the role of winter body mass in reproductive allocation in Norwegian moose.  

PubMed

A life history strategy that favours somatic growth over reproduction is well known for long-lived iteroparous species, especially in unpredictable environments. Risk-sensitive female reproductive allocation can be achieved by a reduced reproductive effort at conception, or the subsequent adjustment of investment during gestation or lactation in response to unexpected environmental conditions or resource availability. We investigated the relative importance of reduced investment at conception compared with later in the reproductive cycle (i.e. prenatal, perinatal or neonatal mortality) in explaining reproductive failure in two high-density moose (Alces alces) populations in southern Norway. We followed 65 multiparous, global positioning system (GPS)-collared females throughout the reproductive cycle and focused on the role of maternal nutrition during gestation in determining reproductive success using a quasi-experimental approach to manipulate winter forage availability. Pregnancy rates in early winter were normal (?0.8) in all years while spring calving rates ranged from 0.4 to 0.83, with prenatal mortality accounting for most of the difference. Further losses over summer reduced autumn recruitment rates to 0.23-0.69, despite negligible predation. Over-winter mass loss explained variation in both spring calving and autumn recruitment success better than absolute body mass in early or late winter. Although pregnancy was related to body mass in early winter, overall reproductive success was unrelated to pre-winter body condition. We therefore concluded that reproductive success was limited by winter nutritional conditions. However, we could not determine whether the observed reproductive allocation adjustment was a bet-hedging strategy to maximise reproduction without compromising survival or whether females were simply unable to invest more resources in their offspring. PMID:23223863

Milner, Jos M; van Beest, Floris M; Solberg, Erling J; Storaas, Torstein

2013-08-01

132

High-shear-rate capillary viscometer for inkjet inks  

SciTech Connect

A capillary viscometer developed to measure the apparent shear viscosity of inkjet inks at high apparent shear rates encountered during inkjet printing is described. By using the Weissenberg-Rabinowitsch equation, true shear viscosity versus true shear rate is obtained. The device is comprised of a constant-flow generator, a static pressure monitoring device, a high precision submillimeter capillary die, and a high stiffness flow path. The system, which is calibrated using standard Newtonian low-viscosity silicone oil, can be easily operated and maintained. Results for measurement of the shear-rate-dependent viscosity of carbon-black pigmented water-based inkjet inks at shear rates up to 2x10{sup 5} s{sup -1} are discussed. The Cross model was found to closely fit the experimental data. Inkjet ink samples with similar low-shear-rate viscosities exhibited significantly different shear viscosities at high shear rates depending on particle loading.

Wang Xi [FUJIFILM Dimatix, Inc., Lebanon, New Hampshire 03766 (United States); Carr, Wallace W.; Bucknall, David G. [School of Polymer, Textile, and Fiber Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Morris, Jeffrey F. [Department of Chemical Engineering and Benjamin Levich Institute for Physico-Chemical Hydrodynamics, City College of New York, New York, New York 10031 (United States)

2010-06-15

133

First domestic high repetition rate ultrashort pulse laser  

Microsoft Academic Search

On 7 February 1985, certification tests were conducted on the High Repetition Rate Ultrashort Pulse Laser. Experts at the meeting pointed out that this was China's first prototype high repetition rate ultrashort pulse laser. Its performance is higher than that of similar lasers in this country and is comparable to the advanced standards of foreign products. The energy of the

Lin Guang

1985-01-01

134

HIGH-RATE DISINFECTION TECHNIQUES FOR COMBIND SEWER OVERFLOW  

EPA Science Inventory

This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH )...

135

High Graduate Unemployment Rate and Taiwanese Undergraduate Education  

ERIC Educational Resources Information Center

An expansion in higher education in combination with the recent global economic recession has resulted in a high college graduate unemployment rate in Taiwan. This study investigates how the high unemployment rate and financial constraints caused by economic cutbacks have shaped undergraduates' class choices, job needs, and future income…

Wu, Chih-Chun

2011-01-01

136

Nanoclay syntactic foam composites—High strain rate properties  

Microsoft Academic Search

The effect of nanoclay on the high strain rate mechanical properties of syntactic foam composites is studied. Nanoclay syntactic foam composites are fabricated with 10, 30 and 60% microballoon volume fractions, each having 0, 1, 2 and 5% volume fraction of nanoclay. High strain rate tests using split Hopkinson pressure bar (SHPB) apparatus are performed on all types of composites.

Sameer Peter; Eyassu Woldesenbet

2008-01-01

137

An empirical test of evolutionary theories for reproductive senescence and reproductive effort in the garter snake Thamnophis elegans  

Microsoft Academic Search

Evolutionary theory predicts that differential reproductive effort and rate of reproductive senescence will evolve under different rates of external mortality. We examine the evolutionary divergence of age-specific reproduction in two life-history ecotypes of the western terrestrial garter snake, Thamnophis elegans. We test for the signature of reproductive senescence (decreasing fecundity with age) and increasing reproductive effort with age (increasing reproductive

Amanda M. Sparkman; Stevan J. Arnold; Anne M. Bronikowski

2007-01-01

138

An ELISA for porcine reproductive and respiratory syndrome: production of antigen of high quality.  

PubMed Central

A reliable method was developed to produce a viral antigen preparation from porcine reproductive and respiratory syndrome virus (PRRSV) infected MARC-145 cells by solubilizing the virus with Triton X-100. This method eliminated problems previously encountered with high background reactions associated with PRRSV antigen or cell control antigen. With this new antigen, an indirect enzyme-linked immunosorbent assay (ELISA) was adapted to detect swine serum anti-body against PRRSV. In the ELISA, non-specific reactions associated with test serum samples have been eliminated by utilizing an effective blocking serum diluent. The ELISA is more sensitive than an indirect immunofluorescent assay (IFA), particularly with late-infection sera, while maintaining a high diagnostic specificity. In a comparison of IFA and ELISA using sera collected from 250 pigs of various ages from 5 herds that had PRRS histories, IFA revealed 178 positive samples and 72 negative samples. All of the IFA-positive sera were proven to be ELISA reactors. However, nearly one-half (34/72) of the IFA-negative samples were also ELISA reactors. The diagnostic specificity and sensitivity of the ELISA were 100% and 96.6% with 257 serum samples collected from known healthy PRRS-negative swine herds and 57 sera collected from infected swine at 6 to 56 days after infection, respectively. The ELISA is technically superior to IFA, time-efficient and cost-effective, and suitable for testing of a large number of samples over a short period of time. PMID:8785725

Cho, H J; Deregt, D; Joo, H S

1996-01-01

139

Effects of high tissue concentrations of selenium on reproduction by bluegills  

SciTech Connect

Recent studies have associated high body concentrations of selenium with declines in fish populations inhabiting cooling reservoirs of coal-fired electric power plants. Because some evidence indicated that these declines resulted from reduced reproduction, the authors made a series of 18 artificial crosses of bluegills Lepomis macrochirus possessing high and low body concentrations of Se to determine whether elevated Se in parents reduced viability of gametes or increased mortality of embryos and larvae. Bluegills with high body concentrations of Se were obtained from Hyco Reservoir (cooling water source of a coal-fired power plant) and those with low body concentrations were obtained from nearby Roxboro City Lake, North Carolina. Neither percent fertilization nor percent hatch of eggs differed significantly among the parent combinations. However, all crosses (8) that included females with high Se body concentrations resulted in larvae with edema; such larvae did not survive to the swim-up stage. Only one of these crosses produced some normal larvae (35%). Mean Se concentrations in the gonads and carcass (body minus gonad) were more than 20 times higher in bluegills from Hyco Reservoir (average = 7.94 mg/kg) than in those from Roxboro City Lake (average = 0.38 mg/kg). The high Se concentrations in ovaries of Hyco Reservoir bluegills and in their progeny suggested that Se was transferred from females to offspring and caused edema in larvae. This abnormality resulted in mortality of affected larval bluegills - and consequently may have caused reductions in the bluegill populations of selenium-enriched reservoirs.

Gillespie, R.B.; Baumann, P.C.

1986-03-01

140

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Estimating bowhead whale population size and rate of increase from the 1993 c...  

E-print Network

Reproduced with permission of the copyright owner. Further reproduction prohibited without. 451 #12;Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. #12;Reproduced with permission of the copyright owner. Further reproduction prohibited without

Raftery, Adrian

141

Endocrinology of year-round reproduction in a highly seasonal habitat: environmental variability in testosterone and glucocorticoids in baboon males  

PubMed Central

In conditions characterized by energetic constraints, such as in periods of low food availability, some trade-offs between reproduction and self-maintenance may be necessary; even year-round breeders may then be forced to exhibit some reproductive seasonality. Prior research has largely focused on female reproduction and physiology, and few studies have evaluated the impact of environmental factors on males. Here we assessed the effects of season and ambient temperatures on fecal glucocorticoid (fGC) and testosterone (fT) levels in male baboons in Amboseli, Kenya. The Amboseli basin is a highly challenging, semi-arid tropical habitat that is characterized by strongly seasonal patterns of rainfall and by high ambient temperatures. We previously reported that female baboons were impacted by these challenging environmental conditions. We ask here whether male baboons in the same environment and groups as females exhibit similar physiological effects. We found that after accounting for male age and individual variability, males exhibited higher fGC levels and lower fT levels during the dry season than during the wet season. Furthermore, fT but not fGC levels were lower in months of high average daily maximum temperatures, suggesting a direct impact of heat on testes. Our results demonstrate that male baboons, like females, experience ecological stress that alters their reproductive physiology. The impact of the environment on male reproduction deserves more attention both in its own right and because alteration in male physiology may contribute to the reduction in female fertility observed in challenging environments. PMID:20721938

Gesquiere, Laurence R.; Onyango, Patrick O.; Alberts, Susan C.; Altmann, Jeanne

2010-01-01

142

Mechanical behaviour of polymers at high rates of strain  

NASA Astrophysics Data System (ADS)

The stress-strain behaviours of polycarbonate (PC) and polyvinylidene difluoride (PVDF) have been measured over a range of strain rates at room temperature and a range of temperatures at high strain rate. Both materials show an approximately bilinear dependence of yield stress on strain rate over the rates examined. The experiments at different temperatures allow the high strain rate glass and ? transitions to be identified in PC, and the melting point and glass transition to be identified in PVDF. These can be confirmed by comparison to Dynamic Mechanical Analysis (DMA) measurements on the materials. Applying a time-temperature superposition to the data shows that these transitions are the cause of the bilinearity in the strain rate dependence of the materials. The behaviour of nominal (or engineering) stress in PC is also examined.

Siviour, C. R.; Walley, S. M.; Proud, W. G.; Field, J. E.

2006-08-01

143

Evaluation of reproductive tract infection during early post-partum period and its relationship with subsequent reproductive performance in high milk producing dairy cows.  

PubMed

Clinically normal Holstein-Friesian cows (n = 43) were used to establish a relationship between the evaluations of the uterine condition by vaginoscopy, Metricheck, endometrial cytology (EC) and ultrasonography (US) during post-partum period (pp), and subsequent reproductive performance. The uterine status of the selected cows was evaluated by EC, Metricheck, US and vaginoscopy on a weekly basis from the third week (W3) to the seventh week (W7) pp. The animals were bred after a voluntary waiting period of 45-60 days pp and diagnosed for pregnancy status at 45 days after breeding by US. First service conception rate (FSCR) of bred animals was 32.6% (14/43). There was no significant difference in polymorphonuclear leucocyte percentage between conceived and non-conceived cows during different weeks post-partum. First service conception rate in animals with normal vaginal discharge as detected by Metricheck was significantly low when compared to those of abnormal discharge during W3 (2.3% vs 30.3%; p?reproductive performance of dairy cattle. PMID:21707786

Senosy, W; Uchiza, M; Tameoka, N; Izaike, Y; Osawa, T

2012-04-01

144

Uncovering high-strain rate protection mechanism in nacre  

PubMed Central

Under high-strain-rate compression (strain rate ?103?s?1), nacre (mother-of-pearl) exhibits surprisingly high fracture strength vis-à-vis under quasi-static loading (strain rate 10?3?s?1). Nevertheless, the underlying mechanism responsible for such sharply different behaviors in these two loading modes remains completely unknown. Here we report a new deformation mechanism, adopted by nacre, the best-ever natural armor material, to protect itself against predatory penetrating impacts. It involves the emission of partial dislocations and the onset of deformation twinning that operate in a well-concerted manner to contribute to the increased high-strain-rate fracture strength of nacre. Our findings unveil that Mother Nature delicately uses an ingenious strain-rate-dependent stiffening mechanism with a purpose to fight against foreign attacks. These findings should serve as critical design guidelines for developing engineered body armor materials. PMID:22355664

Huang, Zaiwang; Li, Haoze; Pan, Zhiliang; Wei, Qiuming; Chao, Yuh J.; Li, Xiaodong

2011-01-01

145

Rate Controlled Servers for Very High-Speed Networks  

Microsoft Academic Search

Future high-speed networks are expected to carry traffic with a wide range of performance requirements. We describe two queue service disciplines, rate-based scheduling and hierarchical round robin scheduling, that allow some connections to receive guaranteed rate and jitter performance, while others receive best effort service. Rate-based scheduling is designed for fast packet networks, while hierarchical round robin is an extension

S. Keshav

1990-01-01

146

Rate Controlled Servers for Very High-speed Networks  

Microsoft Academic Search

Future high-speed networks are expected to carry traffic with a wide range of performance requirements. We describe two queue service disciplines, rate-based scheduling and hierarchical round robin scheduling, that allow some connections to receive guaranteed rate and jitter performance, while others receive best effort service. Rate-based scheduling is designed for fast packet networks, while hierarchical round robin is an extension

C. R. Kalmanek; H. Kanakia; S. Keshav

147

Plants and Photosynthesis: Level III, Unit 3, Lesson 1; The Human Digestive System: Lesson 2; Functions of the Blood: Lesson 3; Human Circulation and Respiration: Lesson 4; Reproduction of a Single Cell: Lesson 5; Reproduction by Male and Female Cells: Lesson 6; The Human Reproductive System: Lesson 7; Genetics and Heredity: Lesson 8; The Nervous System: Lesson 9; The Glandular System: Lesson 10. Advanced General Education Program. A High School Self-Study Program.  

ERIC Educational Resources Information Center

This self-study program for the high-school level contains lessons in the following subjects: Plants and Photosynthesis; The Human Digestive System; Functions of the Blood; Human Circulation and Respiration; Reproduction of a Single Cell; Reproduction by Male and Female Cells; The Human Reproductive System; Genetics and Heredity; The Nervous…

Manpower Administration (DOL), Washington, DC. Job Corps.

148

High Strain Rate Characterisation of a Polymer Bonded Sugar  

Microsoft Academic Search

The mechanical properties of a polymer bonded sugar consisting of 78% sugar crystals, of modal particle size 310 ?m, dispersed in an HTPB binder have been characterized in a split Hopkinson pressure bar system at a strain rate of 103 s?1 and temperatures from ?100 to +20 °C. These high rate experiments were supplemented by further experiments in an Instron

P. R. Laity; C. R. Siviour; P. D. Church; W. G. Proud

2006-01-01

149

High Strain Rate Characterisation of a Polymer Bonded Sugar  

Microsoft Academic Search

The mechanical properties of a polymer bonded sugar consisting of 78% sugar crystals, of modal particle size 310 mum, dispersed in an HTPB binder have been characterized in a split Hopkinson pressure bar system at a strain rate of 103 s-1 and temperatures from -100 to +20 °C. These high rate experiments were supplemented by further experiments in an Instron

P. R. Laity; C. R. Siviour; P. D. Church; W. G. Proud

2006-01-01

150

High rate fingerprinting codes and the fingerprinting capacity Ehsan Amiri  

E-print Network

High rate fingerprinting codes and the fingerprinting capacity Ehsan Amiri G´abor Tardos Abstract fingerprinting codes. In this paper we consider fingerprinting with the mark- ing assumption and design codes possible rate (the fingerprinting capacity) for any fixed number of pirates. We prove new up- per bounds

Tardos, Gábor

151

High rate tensile tests – Measuring equipment and evaluation  

Microsoft Academic Search

Polymers are widely used in protection systems, e.g. in cars. For dimensioning those parts, crash simulation is performed. However, crash simulation programs require reliable high rate mechanical properties to provide accurate results. As polymers are viscoelastic materials Young's modulus and yield stress are rate dependent quantities. In order to determine these properties, special experimental devices and special evaluation methods have

Sven Robert Raisch; Bernhard Möginger

2010-01-01

152

MECHANICAL PROPERTIES AND MICROSTRUCTURAL EVOLUTIONS AT HIGH STRAIN RATES OF  

E-print Network

in military applications such as liner of explosively formed projectiles [1]. During the phase formation of the projectile, the liner material experiences large deformation under high strain rate, that could modify the as

Gubicza, Jenõ

153

Simulating subhaloes at high redshift: merger rates, counts and types  

Microsoft Academic Search

Galaxies are believed to be in one-to-one correspondence with simulated dark matter subhaloes. We use high-resolution N-body simulations of cosmological volumes to calculate the statistical properties of subhalo (galaxy) major mergers at high redshift (z = 0.6-5). We measure the evolution of the galaxy merger rate, finding that it is much shallower than the merger rate of dark matter host

Andrew R. Wetzel; J. D. Cohn; Martin White

2009-01-01

154

Identifying High-Rate Flows Based on Sequential Sampling  

NASA Astrophysics Data System (ADS)

We consider the problem of fast identification of high-rate flows in backbone links with possibly millions of flows. Accurate identification of high-rate flows is important for active queue management, traffic measurement and network security such as detection of distributed denial of service attacks. It is difficult to directly identify high-rate flows in backbone links because tracking the possible millions of flows needs correspondingly large high speed memories. To reduce the measurement overhead, the deterministic 1-out-of-k sampling technique is adopted which is also implemented in Cisco routers (NetFlow). Ideally, a high-rate flow identification method should have short identification time, low memory cost and processing cost. Most importantly, it should be able to specify the identification accuracy. We develop two such methods. The first method is based on fixed sample size test (FSST) which is able to identify high-rate flows with user-specified identification accuracy. However, since FSST has to record every sampled flow during the measurement period, it is not memory efficient. Therefore the second novel method based on truncated sequential probability ratio test (TSPRT) is proposed. Through sequential sampling, TSPRT is able to remove the low-rate flows and identify the high-rate flows at the early stage which can reduce the memory cost and identification time respectively. According to the way to determine the parameters in TSPRT, two versions of TSPRT are proposed: TSPRT-M which is suitable when low memory cost is preferred and TSPRT-T which is suitable when short identification time is preferred. The experimental results show that TSPRT requires less memory and identification time in identifying high-rate flows while satisfying the accuracy requirement as compared to previously proposed methods.

Zhang, Yu; Fang, Binxing; Luo, Hao

155

High strain rate superplasticity in metals and composites  

Microsoft Academic Search

Superplastic behavior at very high strain rates (at or above 1 s⁻¹) in metallic-based materials is an area of increasing interest. The phenomenon has been observed quite extensively in metal alloys, metal-matrix composites (MMC), and mechanically-alloyed (MA) materials. In the present paper, experimental results on high strain rate behavior in 2124 Al-based materials, including Zr-modified 2124, SiC-reinforced 2124, MA 2124,

T. G. Nieh; J. Wadsworth; K. Higashi

1993-01-01

156

Deformation substructures induced by high-rate deformation  

SciTech Connect

The influence of increasing strain on the deformation substructures in metals and alloys which deform predominately by slip is very similar to that seen following quasi-static deformation at increasingly lower temperatures or due to a decrease in stacking fault energy ({gamma}{sub sf}). For constant strain, deformation at higher rates: (1) produces more uniform dislocation distributions for the same amount of strain, (2) hinders dislocation cell formation, (3) decreases the cell size, and (4) increases misorientaion with more dislocations trapped within the cell interiors. The suppression of thermally-activated dislocation processes in this regime, added to high temperature and strain-rate sensitivity of the yield stress exhibited by many materials, can lead to stresses high enough to nucleate and grow deformation twins even in high stacking fault energy FCC metals such as copper and Al-4.8 wt % Mg. In addition, substructures formed under high-rate conditions differ from those formed under low-rate conditions due to the suppression of dynamic recovery process. Finally, in high-rate deformation such as shock loading, the subsonic restriction on dislocation motion leads to higher dislocation and point defect generation rates, resulting in enhanced hardening when compared to materials deformed to equivalent strains at quasi-static rates. In this paper examples of the deformation substructure evolution observed in aluminum, copper, Ni{sub 3}Al, iron, Ti-6Al-4V, and TiAl at high and shock-loading strain rates will be presented and compared to that seen following low-rate deformation paths. 41 refs., 15 figs.

Gray, G.T. III.

1991-01-01

157

High-throughput reproduction of the Morpho butterfly's specific high contrast blue  

NASA Astrophysics Data System (ADS)

Some species of the blue Morpho butterfly have a mysterious physical feature of strucural color, because it has both high reflectivity (>60%) and a single color in too wide angular range (> +/- 40° from the normal), which are contradicting with each other in consideration of the interference phenomena. We have recently proven the principle of the mystery by extracting the physical essence, and emulating the nano-structures using nano-fabrication techniques. The essence was special combination of regular and irregular structures at nanometer scale. Such artificial structural color was found to concern wide applications, because the Morpho-color can produce a single color without pigment in wide angular range with high reflectivity. Also it makes colors impossible by pigment, and is resistant to fading due to chemical change over longtime. However, we must overcome several "death valleys" for wide industrial applications. One of the most serious problems was extremely low throughput in the fabrication process of nano-patterning by the conventional lithography. This difficulty was solved by use of the nano-imprinting technique. However, from the practical viewpoint, the enlargement of the mold area for nano-imprinting process was essential. This problem was found to be solved using the laser fabrication and electroforming processes. Nevertheless, to reproduce the clear blue contrast of the Morpho-color, a blackening treatment at the film interface was found to be necessary. The blackening processes and conditions by use of absorbing layers were then estimated and successfully applied to reproduce the clear contrast of the Morpho-blue, which has been confirmed by the optical measurement of the reflectivity.

Saito, Akira; Murase, Junichi; Yonezawa, Masaru; Watanabe, Hiroyuki; Shibuya, Takuto; Sasaki, Mitsuo; Ninomiya, Takafumi; Noguchi, Shunji; Akai-kasaya, Megumi; Kuwahara, Yuji

2012-04-01

158

Evaluation of the Pathogenicity of a Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus Variant in Piglets  

Microsoft Academic Search

Since May 2006, a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China's pig industry. To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV, 3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative

Tian-chao WEI; Zhi-jun TIAN; Yan-jun ZHOU; Tong-qing AN; Yi-feng JIANG; Yan XIAO; Shouping HU; Jin-mei PENG; Xiao-fang HAO; Shan-rui ZHANG; Guang-zhi TONG

2011-01-01

159

High strain rate loading of polymeric foams and solid plastics  

NASA Astrophysics Data System (ADS)

The split-Hopkinson pressure bar (SHPB) provided a technique to determine the high strain rate response for low density foams and solid ABS and polypropylene plastics. These materials are used in the interior safety panels of automobiles and crash test dummies. Because the foams have a very low impedance, polycarbonate bars were used to acquire the strain rate data in the 100 to 1600 l/s range. An aluminum SPHB setup was used to obtain the solid plastics data which covered strain rates of 1000 to 4000 l/s. The curves for peak strain rate versus peak stress for the foams over the test range studied indicates only a slight strain rate dependence. Peak strain rate versus peak stress curves for polypropylene shows a strain rate dependence up to about 1500 l/s. At that rate the solid poly propylene indicates no strain rate dependence. The ABS plastics are strain rate dependent up to 3500 l/s and then are independent at larger strain rates.

Dick, Richard D.; Chang, Peter C.; Fourney, William L.

2000-04-01

160

Slow rate of molecular evolution in?high-elevation?hummingbirds  

PubMed Central

Estimates of relative rates of molecular evolution from a DNA-hybridization phylogeny for 26 hummingbird species provide evidence for a negative association between elevation and rate of single-copy genome evolution. This effect of elevation on rate remains significant even after taking into account a significant negative association between body mass and molecular rate. Population-level processes do not appear to account for these patterns because (i) all hummingbirds breed within their first year and (ii) the more extensive subdivision and speciation of bird populations living at high elevations predicts a positive association between elevation and rate. The negative association between body mass and molecular rate in other organisms has been attributed to higher mutation rates in forms with higher oxidative metabolism. As ambient oxygen tensions and temperature decrease with elevation, the slow rate of molecular evolution in high-elevation hummingbirds also may have a metabolic basis. A slower rate of single-copy DNA change at higher elevations suggests that the dynamics of molecular evolution cannot be separated from the environmental context. PMID:9435240

Bleiweiss, Robert

1998-01-01

161

Reproductive limits of a late-flowering high-mountain Mediterranean plant along an elevational climate gradient.  

PubMed

Mountain plants are particularly sensitive to climate warming because snowmelt timing exerts a direct control on their reproduction. Current warming is leading to earlier snowmelt dates and longer snow-free periods. Our hypothesis is that high-mountain Mediterranean plants are not able to take advantage of a lengthened snow-free period because this leads to longer drought that truncates the growing season. However, reproductive timing may somewhat mitigate these negative effects through temporal shifts. We assessed the effects of flowering phenology on the reproductive success of Silene ciliata, a Mediterranean high-mountain plant, across an altitudinal gradient during two climatically contrasting years. The species showed a late-flowering pattern hampering the use of snowmelt water. Plant fitness was largely explained by the elapsed time from snowmelt to onset of flowering, suggesting a selective pressure towards early flowering caused by soil moisture depletion. The proportion of flowering plants decreased at the lowest population, especially in the drier year. Plants produced more flowers, fruits and seeds at the highest population and in the mild year. Our results indicate that water deficit in dry years could threaten the lowland populations of this mountainous species, while high-altitude environments are more stable over time. PMID:17204083

Giménez-Benavides, L; Escudero, A; Iriondo, J M

2007-01-01

162

Solidification at the High and Low Rate Extreme  

SciTech Connect

The microstructures formed upon solidification are strongly influenced by the imposed growth rates on an alloy system. Depending on the characteristics of the solidification process, a wide range of growth rates is accessible. The prevailing solidification mechanisms, and thus the final microstructure of the alloy, are governed by these imposed growth rates. At the high rate extreme, for instance, one can have access to novel microstructures that are unattainable at low growth rates. While the low growth rates can be utilized for the study of the intrinsic growth behavior of a certain phase growing from the melt. Although the length scales associated with certain processes, such as capillarity, and the diffusion of heat and solute, are different at low and high rate extremes, the phenomena that govern the selection of a certain microstructural length scale or a growth mode are the same. Consequently, one can analyze the solidification phenomena at both high and low rates by using the same governing principles. In this study, we examined the microstructural control at both low and high extremes. For the high rate extreme, the formation of crystalline products and factors that control the microstructure during rapid solidification by free-jet melt spinning are examined in Fe-Si-B system. Particular attention was given to the behavior of the melt pool at different quench-wheel speeds. Since the solidification process takes place within the melt-pool that forms on the rotating quench-wheel, we examined the influence of melt-pool dynamics on nucleation and growth of crystalline solidification products and glass formation. High-speed imaging of the melt-pool, analysis of ribbon microstructure, and measurement of ribbon geometry and surface character all indicate upper and lower limits for melt-spinning rates for which nucleation can be avoided, and fully amorphous ribbons can be achieved. Comparison of the relevant time scales reveals that surface-controlled melt-pool oscillation may be the dominant factor governing the onset of unsteady thermal conditions accompanied by varying amounts of crystalline nucleation observed near the lower limit. At high quench-wheel velocities, the influence of these oscillations is minimal due to very short melt-pool residence times. However, microstructural evidence suggests that the entrapment of gas pockets at the wheel-metal interface plays a critical role in establishing the upper rate limit. An observed transition in wheel-side surface character with increasing melt-spinning rate supports this conclusion.

Halim Meco

2004-12-19

163

Effects of rumen-inert fat on lactation, reproduction, and health of high producing Holstein herds.  

PubMed

Two hundred twenty of 443 cows freshening between June 1989 and March 1990 in five commercial Holstein herds were fed .45 kg/d of rumen-inert fat from calving until 200 DIM. Control diets were fed as TMR and contained, on average, 3.7 to 4.8% supplemental fat (DM basis). Test herds had rolling herd averages of 9300 to 13,250 kg of milk. Production of 4% FCM and milk increased 1.01 (3.3%) and 1.50 kg/d (4.6%), respectively, for primiparous cows fed additional fat. Multiparous cows from four herds demonstrated no response; multiparous cows in one herd increased production of 4% FCM by 2.88 kg/d (8.2%), milk by 2.45 kg/d (6.4%), and milk fat by .14kg/d (10.6%) in response to additional fat. An explanation of response differences among herd for multiparous cows was not possible. For primiparous and multiparous cows, increased genetic potential increased treatment response. Increased body condition score at calving influenced treatment response of multiparous cows. Thinner cows produced more milk and less milk fat in response to additional dietary fat than did fatter cows. Most reproductive indices were unaffected by treatment. Cows receiving additional fat had lower, but nonsignificantly lower, incidences of most health disorders. Responses to rumen-inert fat by cows receiving high concentrations of dietary fat were marginal and were affected by body condition score at calving and by genetic potential. PMID:8747335

Scott, T A; Shaver, R D; Zepeda, L; Yandell, B; Smith, T R

1995-11-01

164

Statistical profiles of highly-rated web sites  

Microsoft Academic Search

We are creating an interactive tool to help non-professional web site builders create high quality designs. We have previously reported that quantitative measures of web page structure can predict whether a site will be highly or poorly rated by experts, with accuracies ranging from 67--80%. In this paper we extend that work in several ways. First, we compute a much

Melody Y. Ivory; Marti A. Hearst

2002-01-01

165

Experimental mechanics at velocity extremes —Very high strain rates  

Microsoft Academic Search

The early experimental work of Clark and Wood with regard to von Kármán's theory on the effect of material flow and fracture at high strain rates has led to many controversial issues on these effects. Interest has been greatly revived in recent years because of the increased emphasis on such high-velocity forming processes as explosive and capacitor discharge. Considerable new

W. W. Wood

1967-01-01

166

Breakdown Limit Studies in High-Rate Gaseous Detectors  

NASA Technical Reports Server (NTRS)

We report results from a systematic study of breakdown limits for novel high-rate gaseous detectors: MICROMEGAS, CAT and GEM, together with more conventional devices such as thin-gap parallel-mesh chambers and high-rate wire chambers. It was found that for all these detectors, the maximum achievable pin, before breakdown appears, drops dramatically with incident flux, and is sometimes inversely proportional to it. Further, in the presence of alpha particles, typical of the breakgrounds in high-energy experiments, additional gain drops of 1-2 orders of magnitude were observed for many detectors. It was found that breakdowns at high rates occur through what we have termed an "accumulative" mechanism, which does not seem to have been previously reported in the literature. Results of these studies may help in choosing the optimum detector for given experimental conditions.

Ivaniouchenkov, Yu; Fonte, P.; Peskov, V.; Ramsey, B. D.

1999-01-01

167

Evolution of High Tooth Replacement Rates in Sauropod Dinosaurs  

PubMed Central

Background Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. Methodology/Principal Findings We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days). Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. Conclusions/Significance Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size), and derived titanosaurs and diplodocoids independently evolved the highest known tooth replacement rates among archosaurs. PMID:23874921

Smith, Kathlyn M.; Fisher, Daniel C.; Wilson, Jeffrey A.

2013-01-01

168

Teaching Plant Reproduction.  

ERIC Educational Resources Information Center

Recommends using Amaryllis hippeastrum to teach young children about plant reproduction. Provides tips for growing these plants, discusses the fast growing rate of the plant, and explains the anatomy. (YDS)

Tolman, Marvin N., Ed.; Hardy, Garry R., Ed.

2000-01-01

169

High Strain Rate Behavior of Polymer Matrix Composites Analyzed  

NASA Technical Reports Server (NTRS)

Procedures for modeling the high-speed impact of composite materials are needed for designing reliable composite engine cases that are lighter than the metal cases in current use. The types of polymer matrix composites that are likely to be used in such an application have a deformation response that is nonlinear and that varies with strain rate. To characterize and validate material models that could be used in the design of impactresistant engine cases, researchers must obtain material data over a wide variety of strain rates. An experimental program has been carried out through a university grant with the Ohio State University to obtain deformation data for a representative polymer matrix composite for strain rates ranging from quasi-static to high rates of several hundred per second. This information has been used to characterize and validate a constitutive model that was developed at the NASA Glenn Research Center.

Goldberg, Robert K.; Roberts, Gary D.

2001-01-01

170

High-strain-rate measurements of dislocation mobility  

SciTech Connect

The strain rate sensitivity in a variety of metals is known to increase dramatically when the strain rate exceeds about 10/sup 3/ s/sup -1/. In copper, this behavior is analyzed in terms of the transition in rate controlling deformation mechanism from thermal activation to dislocation drag. Experimental results can be made to agree with a model of this transition, which leads to several observations regarding dislocation mobility at these high strain rates. The mobile dislocation density is estimated to be a mildly increasing function of stress or strain rate at any one strain and is roughly independent of strain for 0.05 less than or equal to epsilon less than or equal to 0.20.

Follansbee, P.S.; Regazzoni, G.; Kocks, U.F.

1984-05-01

171

Study of High Strain Rate Response of Composites  

NASA Technical Reports Server (NTRS)

The objective of the research was to continue the experimental study of the effect of strain rate on mechanical response (deformation and failure) of epoxy resins and carbon fibers/epoxy matrix composites, and to initiate a study of the effects of temperature by developing an elevated temperature test. The experimental data provide the information needed for NASA scientists for the development of a nonlinear, rate dependent deformation and strength models for composites that can subsequently be used in design. This year effort was directed into testing the epoxy resin. Three types of epoxy resins were tested in tension and shear at various strain rates that ranges from 5 x 10(exp -5), to 1000 per second. Pilot shear experiments were done at high strain rate and an elevated temperature of 80 C. The results show that all, the strain rate, the mode of loading, and temperature significantly affect the response of epoxy.

Gilat, Amos

2003-01-01

172

Study of magnetorheological fluids at high shear rates  

Microsoft Academic Search

The tunable rheological properties of magnetorheological (MR) materials at high shear rates are studied using a piston-driven flow-mode-type rheometer. The proposed method provides measurement of the apparent viscosity and yield stress of MR fluids for a shear rate range of 50 to 40,000 s?1. The rheological properties of a commercial MR fluid, as well as a newly developed MR polymeric gel,

Xiaojie Wang; Faramarz Gordaninejad

2006-01-01

173

High strain-rate model for fiber-reinforced composites  

Microsoft Academic Search

Numerical simulations of dynamic uniaxial strain loading of fiber-reinforced composites are presented that illustrate the wide range of deformation mechanisms that can be captured using a micromechanics-based homogenization technique as the material model in existing continuum mechanics computer programs. Enhancements to the material model incorporate high strain-rate plastic response, elastic nonlinearity, and rate-dependent strength degradation due to material damage, fiber

J. B. Aidun; F. L. Addessio

1995-01-01

174

Constitutive model for high strain rate response of polymeric composites  

Microsoft Academic Search

A constitutive model for characterizing high strain rate response of polymeric composites was developed using off-axis composite specimens. The difference in the results of coupon and block specimens was experimentally demonstrated and discussed. Off-axis block specimens were tested in compression at three different strain rates, 10?4\\/s, 10?2\\/s, and 1\\/s. Based on these experimental data, a viscoplasticity model was established to

J. Tsai; C. T. Sun

2002-01-01

175

Damage formation during high strain rate deformation of PBS9501  

NASA Astrophysics Data System (ADS)

A key aspect of the response of an explosive formulation to high strain rate loading is damage formation. In addition to the effect on immediate strength properties, damage, once formed, can lead to an undesirable increase in sensitivity and rate of burning. Methodologies for understanding and characterising the damage formed during loading are therefore vital if we are to claim a true understanding of the mechanical properties of these materials. This paper presents results from experiments on stimulant, PBS9501, of a polymer bonded explosive. High strain rate loading was performed in a split Hopkinson pressure bar, using speckle metrology and high speed photography to build up a more complete data-set on the formation of damage in this material. X-ray microtomography was also applied to examine internal damage in recovered specimens.

Siviour, Clive; Proud, William

2007-06-01

176

High strain rate compression testing of glass fibre reinforced polypropylene  

NASA Astrophysics Data System (ADS)

This paper details an investigation of the high strain rate compression testing of GFPP with the Split Hopkinson Pressure Bar (SHPB) in the through-thickness and in-plane directions. GFPP posed challenges to SHPB testing as it fails at relatively high stresses, while having relatively low moduli and hence mechanical impedance. The modifications to specimen geometry and incident pulse shaping in order to gather valid test results, where specimen equilibrium was achieved for SHPB tests on GFPP are presented. In addition to conventional SHPB tests to failure, SHPB experiments were designed to achieve specimen equilibration at small strains, which permitted the capture of high strain rate elastic modulus data. The strain rate dependency of GFPP's failure strengths in the in-plane and through-thickness direction is modelled using a logarithmic law.

Govender, R. A.; Langdon, G. S.; Cloete, T. J.; Nurick, G. N.

2012-08-01

177

Flexible high-repetition-rate ultrafast fiber laser  

PubMed Central

High-repetition-rate pulses have widespread applications in the fields of fiber communications, frequency comb, and optical sensing. Here, we have demonstrated high-repetition-rate ultrashort pulses in an all-fiber laser by exploiting an intracavity Mach-Zehnder interferometer (MZI) as a comb filter. The repetition rate of the laser can be tuned flexibly from about 7 to 1100?GHz by controlling the optical path difference between the two arms of the MZI. The pulse duration can be reduced continuously from about 10.1 to 0.55?ps with the spectral width tunable from about 0.35 to 5.7?nm by manipulating the intracavity polarization controller. Numerical simulations well confirm the experimental observations and show that filter-driven four-wave mixing effect, induced by the MZI, is the main mechanism that governs the formation of the high-repetition-rate pulses. This all-fiber-based laser is a simple and low-cost source for various applications where high-repetition-rate pulses are necessary. PMID:24226153

Mao, Dong; Liu, Xueming; Sun, Zhipei; Lu, Hua; Han, Dongdong; Wang, Guoxi; Wang, Fengqiu

2013-01-01

178

Flexible high-repetition-rate ultrafast fiber laser  

NASA Astrophysics Data System (ADS)

High-repetition-rate pulses have widespread applications in the fields of fiber communications, frequency comb, and optical sensing. Here, we have demonstrated high-repetition-rate ultrashort pulses in an all-fiber laser by exploiting an intracavity Mach-Zehnder interferometer (MZI) as a comb filter. The repetition rate of the laser can be tuned flexibly from about 7 to 1100 GHz by controlling the optical path difference between the two arms of the MZI. The pulse duration can be reduced continuously from about 10.1 to 0.55 ps with the spectral width tunable from about 0.35 to 5.7 nm by manipulating the intracavity polarization controller. Numerical simulations well confirm the experimental observations and show that filter-driven four-wave mixing effect, induced by the MZI, is the main mechanism that governs the formation of the high-repetition-rate pulses. This all-fiber-based laser is a simple and low-cost source for various applications where high-repetition-rate pulses are necessary.

Mao, Dong; Liu, Xueming; Sun, Zhipei; Lu, Hua; Han, Dongdong; Wang, Guoxi; Wang, Fengqiu

2013-11-01

179

Simulating Subhalos at High Redshift: Merger Rates, Counts, and Types  

Microsoft Academic Search

Galaxies are believed to be in one-to-one correspondence with simulated dark\\u000amatter subhalos. We use high-resolution N-body simulations of cosmological\\u000avolumes to calculate the statistical properties of subhalo (galaxy) major\\u000amergers at high redshift (z=0.6-5). We measure the evolution of the galaxy\\u000amerger rate, finding that it is much shallower than the merger rate of dark\\u000amatter host halos at

Andrew R. Wetzel; J. D. Cohn; Martin White

2008-01-01

180

High removal rate laser-based coating removal system  

DOEpatents

A compact laser system that removes surface coatings (such as paint, dirt, etc.) at a removal rate as high as 1000 ft.sup.2 /hr or more without damaging the surface. A high repetition rate laser with multiple amplification passes propagating through at least one optical amplifier is used, along with a delivery system consisting of a telescoping and articulating tube which also contains an evacuation system for simultaneously sweeping up the debris produced in the process. The amplified beam can be converted to an output beam by passively switching the polarization of at least one amplified beam. The system also has a personal safety system which protects against accidental exposures.

Matthews, Dennis L. (Moss Beach, CA); Celliers, Peter M. (Berkeley, CA); Hackel, Lloyd (Livermore, CA); Da Silva, Luiz B. (Danville, CA); Dane, C. Brent (Livermore, CA); Mrowka, Stanley (Richmond, CA)

1999-11-16

181

High Rates of Protein Synthesis by Isolated Chloroplasts 1  

PubMed Central

Improvements are described in the preparation and in vitro conditions of an intact pea (Pisum sativum Progress No. 9) chloroplast system which provides high efficiency for translation of endogenous messenger RNA, using light as an energy source. High rates result in the incorporation into protein of up to 100 nanomoles tritiated leucine per milligram chlorophyll. These rates suggest extensive reinitiation, and repeated utilization of the messenger RNA that code for thylakoid proteins. Up to 39 radioactive thylakoid peptide bands were detected by fluorography after labeling with tritiated leucine. Images Fig. 7 Fig. 8 PMID:16662622

Fish, Leonard E.; Jagendorf, Andre T.

1982-01-01

182

GPU accelerated OCT processing at megahertz axial scan rate and high resolution video rate volumetric rendering  

NASA Astrophysics Data System (ADS)

In this report, we describe how to highly optimize a CUDA based platform to perform real time optical coherence tomography data processing and 3D volumetric rendering using commercially-available cost-effective graphic processing units (GPUs). The maximum complete attainable axial scan processing rate (including memory transfer and rendering frame) was 2.2 megahertz for 16 bits pixel depth and 2048 pixels/A-scan, the maximum 3D volumetric rendering speed is 23 volumes/second (size:1024×256×200). To the best of our knowledge, this is the fastest processing rate reported to date with single-chip GPU and the first implementation of real time video rate volumetric OCT processing and rendering that is capable of matching the ultrahigh-speed OCT acquisition rates.

Jian, Yifan; Wong, Kevin; Sarunic, Marinko V.

2013-03-01

183

Reproductive performance of pubertal red deer (Cervus elaphus) hinds: effects of genetic introgression of wapiti subspecies on pregnancy rates at 18 months of age.  

PubMed

Low reproductive productivity of young red deer (Cervus elaphus) hinds on New Zealand deer farms appears to reflect high incidences of puberty failure at 16 months of age. This is despite the general attainment of average liveweights 15-25 kg in excess of the accepted minimum threshold for puberty in subspecies of western European origin (scoticus, elaphus and hippelaphus) that form the basis of the national herd. The present study tests the hypotheses that introgression of the larger North American wapiti subspecies (nelsoni, manitobensis and roosevelti) into breeding herds (1) can be assessed from morphological features of individuals, (2) that there is a relationship between the level of wapiti parentage and non-pregnancy rate at 18 months of age (a proxy for puberty failure) and (3) that minimum liveweight thresholds for puberty increase with increasing levels of wapiti parentage. A total of 4329 18-month-old hinds across four "red" deer farms in southern New Zealand were scanned for pregnancy status. Each hind was assigned a wapiti score (WS) as a subjective assessment of the obviousness of wapiti features. Various body measurements were additionally recorded for each hind. A hair sample was collected for DNA analysis (14 markers) to objectively assign subspecies pedigree (i.e. "Elkmeter") on a subset of 1258 individuals. A total of 506 (11.7%) hinds were not pregnant at 18 months of age with rates varying between 4.1 and 37.3% between farms and years. Mean WS differed significantly between farms and reflected the genetic management policy of each farm. WS was positively correlated to Elkmeter for each farm/year (<0.05) although regression slopes varied significantly. WS was able to be adjusted for these differences to assign a corrected WS (CWS) for all 4329 individuals that estimated the proportion wapiti parentage. Discriminant analysis of morphological variables relative to Elkmeter supported the first hypothesis and showed that shoulder height and body length were good indicators of the degree of wapiti parentage within individuals. This enabled the development of an objective estimate of wapiti parentage (EWP). The actual level of such parentage within herds ranged from <5 to >55%. There was a significant negative association between wapiti parentage and pregnancy, which was strongly influenced by liveweight, supporting the second and third hypotheses. This was manifest as marked displacement of pregnancy probability curves in relation to liveweight between genotype groups, particularly for those groups with >20% wapiti parentage. For example, predicted threshold liveweights required to achieve a 90% pregnancy rate for EWP values that represent 0, 10, 20, 30, 40 and 50% wapiti parentage were 81, 81, 85, 106, 127 and approximately 137 kg, respectively. Within the study herds, the majority of hinds of 0-20% wapiti parentage exceeded the predicted 90% threshold liveweights for their genotype cohort. However, hinds with higher levels of wapiti parentage generally fell below the predicted threshold for their genotype group. The data strongly suggest that under liveweight performance levels measured for red deer, hinds with >20% wapiti parentage are at high risk of puberty failure. PMID:16298276

Asher, G W; Archer, J A; Scott, I C; O'Neill, K T; Ward, J; Littlejohn, R P

2005-12-01

184

Beam combined laser fusion driver with high power and high repetition rate using stimulated Brillouin scattering  

E-print Network

Beam combined laser fusion driver with high power and high repetition rate using stimulated laser fusion energy generation, it is necessary to have a M-J laser system with a repetition rate over of the high power laser. In this paper, we present the recent results about the beam combination laser

Kim, Yong Jung

185

High strength and high strain rate superplasticity in a Mg-Mg 2Si composite  

Microsoft Academic Search

The Mg-Mg2Si composite processed from rapidly solidified ribbons exhibited high strength of about 500 MPa at room temperature and superplastic behavior at high strain rates of 10?1 ~ 1 s?1 at 773 K. The high strain rate superplasticity is attributed to the very small grain size of about 1 ?m.

M. Mabuchi; K. Kubota; K. Higashi

1995-01-01

186

High frame rate CCD camera with fast optical shutter  

SciTech Connect

A high frame rate CCD camera coupled with a fast optical shutter has been designed for high repetition rate imaging applications. The design uses state-of-the-art microchannel plate image intensifier (MCPII) technology fostered/developed by Los Alamos National Laboratory to support nuclear, military, and medical research requiring high-speed imagery. Key design features include asynchronous resetting of the camera to acquire random transient images, patented real-time analog signal processing with 10-bit digitization at 40--75 MHz pixel rates, synchronized shutter exposures as short as 200pS, sustained continuous readout of 512 x 512 pixels per frame at 1--5Hz rates via parallel multiport (16-port CCD) data transfer. Salient characterization/performance test data for the prototype camera are presented, temporally and spatially resolved images obtained from range-gated LADAR field testing are included, an alternative system configuration using several cameras sequenced to deliver discrete numbers of consecutive frames at effective burst rates up to 5GHz (accomplished by time-phasing of consecutive MCPII shutter gates without overlap) is discussed. Potential applications including dynamic radiography and optical correlation will be presented.

Yates, G.J.; McDonald, T.E. Jr. [Los Alamos National Lab., NM (United States); Turko, B.T. [Lawrence Berkeley National Lab., CA (United States)

1998-09-01

187

An overview of male reproductive studies of boron with an emphasis on studies of highly exposed Chinese workers.  

PubMed

Boron treatment of rats, mice, and dogs has been associated with testicular toxicity, characterized by inhibited spermiation at lower dose levels and a reduction in epididymal sperm count at higher dose levels. The no-adverse-effect level for reproductive effects in male rats is 17.5mg B/kg bw/day. Earlier studies in human workers and populations have not identified adverse effects of boron exposure on fertility, but outcome measures in these studies were relatively insensitive, based mainly on family size and did not include an evaluation of semen end points. A recent study of nearly 1000 men working in boron (B) mining or processing in Liaoning province in northeast China has been published in several Chinese and a few English language papers. This study included individual assessment of boron exposure, interview data on reproductive experience and semen analysis. Employed men living in the same community and in a remote community were used as controls. Boron workers (n=75) had a mean daily boron intake of 31.3mg B/day, and a subset of 16 of these men, employed at a plant where there was heavy boron contamination of the water supply, had an estimated mean daily boron intake of 125 mg B/day. Estimates of mean daily boron intake in local community and remote background controls were 4.25mg B/day and 1.40 mg/day, respectively. Reproductive outcomes in the wives of 945 boron workers were not significantly different from outcomes in the wives of 249 background control men after adjustment for potential confounders. There were no statistically significant differences in semen characteristics between exposure groups, including in the highly exposed subset, except that sperm Y:X ratio was reduced in boron workers. Within exposure groups the Y:X ratio did not correlate with the boron concentration in blood, semen and urine. In conclusion, while boron has been shown to adversely affect male reproduction in laboratory animals, there is no clear evidence of male reproductive effects attributable to boron in studies of highly exposed workers. PMID:19850122

Scialli, Anthony R; Bonde, Jens Peter; Brüske-Hohlfeld, Irene; Culver, B Dwight; Li, Yanhong; Sullivan, Frank M

2010-01-01

188

Mechanism of high strain rate superplasticity in aluminium alloy composites  

Microsoft Academic Search

A constitutive equation has been obtained through an analysis of high strain rate superplasticity (HSRS) data on a 2124 Al?Si?3N4 composite. The parametric dependencies of HSRS in composites are different from those observed in conventional aluminium alloys and mechanically alloyed alloys. The HSRS in composites exhibits high activation energy values of 293–338 kJ mol?1 and an inverse grain size and

R. S. Mishra; T. R. Bieler; A. K. Mukherjee

1997-01-01

189

Adiabatic shearband in WHA in high-strain-rate compression  

Microsoft Academic Search

Using UCSD's recovery Hopkinson technique [Nemat-Nasser, S., Isaacs, J.B., Starrett, J.E., 1991. Hopkinson techniques for dynamic recovery experiments. Proc. R. Soc. London, A135, 371], enhanced for high-temperature compression experiments [Nemat-Nasser, S., Isaacs, J., 1997. Direct measurement of isothermal flow stress of metal at elevated temperatures and high strain rates. Acta. Met., 45, 907], two techniques are developed to create adiabatic

D. S. Kim; S. Nemat-Nasser; J. B. Isaacs; D. Lischer

1998-01-01

190

Reliability modeling of electronic systems subjected to high strain rates  

Microsoft Academic Search

Electronic products are subjected to high G-levels during mechanical shock and vibration. Failure-modes include solder-joint failures, pad cratering, chip-cracking, copper trace fracture, and underfill fillet failures. The second-level interconnects may be experience high-strain rates and accrue damage during repetitive exposure to mechanical shock. Industry migration to leadfree solders has resulted in proliferation of a wide variety of solder alloy compositions.

Pradeep Lall; Sandeep Shantaram; David Locker

2012-01-01

191

High-rate quantum cryptography in untrusted networks  

E-print Network

We extend the field of continuous-variable quantum cryptography to a network formulation where two honest parties connect to an untrusted relay by insecure quantum links. To generate secret correlations, they transmit coherent states to the relay where a continuous-variable Bell detection is performed and the outcome broadcast. Even though the detection could be fully corrupted and the links subject to optimal coherent attacks, the honest parties can still extract a secret key, achieving high rates when the relay is proximal to one party, as typical in public networks with access points or proxy servers. Our theory is confirmed by an experiment generating key-rates which are orders of magnitude higher than those achievable with discrete-variable protocols. Thus, using the cheapest possible quantum resources, we experimentally show the possibility of high-rate quantum key distribution in network topologies where direct links are missing between end-users and intermediate relays cannot be trusted.

Stefano Pirandola; Carlo Ottaviani; Gaetana Spedalieri; Christian Weedbrook; Samuel L. Braunstein; Seth Lloyd; Tobias Gehring; Christian S. Jacobsen; Ulrik L. Andersen

2014-08-01

192

Evaluation of advanced high rate Li-SOCl2 cells  

NASA Technical Reports Server (NTRS)

Under NASA sponsorship, JPL is developing advanced, high rate Li-SOCl2 cells for future space missions. As part of this effort, Li-SOCl2 cells of various designs were examined for performance and safety. The cells differed from one another in several aspects, such as: nature of carbon cathode, catalysts, cell configuration, case polarity, and safety devices. Performance evaluation included constant-current discharge over a range of currents and temperatures. Abuse-testing consisted of shortcircuiting, charging, and over-discharge. Energy densities greater than 300 Wh/Kg at the C/2 rate were found for some designs. A cell design featuring a high-surface-area carbon cathode was found to deliver nearly 500 Wh/Kg at moderate discharge rates. Temperature influenced the performance significantly.

Deligiannis, F.; Ang, V.; Dawson, S.; Frank, H.; Subbarao, S.

1986-01-01

193

Method and Apparatus for High Data Rate Demodulation  

NASA Technical Reports Server (NTRS)

A method to demodulate BPSK or QPSK data using clock rates for the receiver demodulator of one-fourth the data rate is presented. This is accomplished through multirate digital signal processing techniques. The data is sampled with an analog-to-digital converter and then converted from a serial data stream to a parallel data stream. This signal processing requires a clock cycle four times the data rate. Once converted into a parallel data stream, the demodulation operations including complex baseband mixing, lowpass filtering, detection filtering, symbol-timing recovery, and carrier recovery are all accomplished at a rate one-fourth the data rate. The clock cycle required is one-sixteenth that required by a traditional serial receiver based on straight convolution. The high rate data demodulator will demodulate BPSK, QPSK, UQPSK, and DQPSK with data rates ranging from 10 Mega-symbols to more than 300 Mega-symbols per second. This method requires less clock cycles per symbol tan traditional serial convolution techniques.

Grebowsky, Gerald J. (Inventor); Gray, Andrew A. (Inventor); Srinivasan, Meera (Inventor)

2001-01-01

194

Corrected High-Frame Rate Anchored Ultrasound with Software Alignment  

ERIC Educational Resources Information Center

Purpose: To improve lingual ultrasound imaging with the Corrected High Frame Rate Anchored Ultrasound with Software Alignment (CHAUSA; Miller, 2008) method. Method: A production study of the IsiXhosa alveolar click is presented. Articulatory-to-acoustic alignment is demonstrated using a Tri-Modal 3-ms pulse generator. Images from 2 simultaneous…

Miller, Amanda L.; Finch, Kenneth B.

2011-01-01

195

READOUT ELECTRONICS FOR A HIGH-RATE CSC DETECTOR  

SciTech Connect

A readout system for a high-rate muon Cathode Strip Chamber (CSC) is described. The system, planned for use in the forward region of the ATLAS muon spectrometer, uses two custom CMOS integrated circuits to achieve good position resolution at a flux of up to 2,500 tracks/cm{sup 2}/s.

OCONNOR,P.; GRATCHEV,V.; KANDASAMY,A.; POLYCHRONAKOS,V.; TCHERNIATINE,V.; PARSONS,J.; SIPPACH,W.

1999-09-25

196

Plant respirometer enables high resolution of oxygen consumption rates  

NASA Technical Reports Server (NTRS)

Plant respirometer permits high resolution of relatively small changes in the rate of oxygen consumed by plant organisms undergoing oxidative metabolism in a nonphotosynthetic state. The two stage supply and monitoring system operates by a differential pressure transducer and provides a calibrated output by digital or analog signals.

Foster, D. L.

1966-01-01

197

Cassini High Rate Detector V14.0  

NASA Astrophysics Data System (ADS)

The High Rate Detector (HRD) from the University of Chicago is an independent part of the CDA instrument on the Cassini Orbiter that measures the dust flux and particle mass distribution of dust particles hitting the HRD detectors. This data set includes all data from the HRD through December 31, 2013. Please refer to Srama et al. (2004) for a detailed HRD description.

Economou, T.; DiDonna, P.

2014-06-01

198

Cassini High Rate Detector V11.0  

NASA Astrophysics Data System (ADS)

The High Rate Detector (HRD) from the University of Chicago is an independent part of the CDA instrument on the Cassini Orbiter that measures the dust flux and particle mass distribution of dust particles hitting the HRD detectors. This data set includes all data from the HRD through December 31, 2011. Please refer to Srama et al. (2004) for a detailed HRD description.

Economou, T.; DiDonna, P.

2012-06-01

199

Cassini High Rate Detector V12.0  

NASA Astrophysics Data System (ADS)

The High Rate Detector (HRD) from the University of Chicago is an independent part of the CDA instrument on the Cassini Orbiter that measures the dust flux and particle mass distribution of dust particles hitting the HRD detectors. This data set includes all data from the HRD through December 31, 2012. Please refer to Srama et al. (2004) for a detailed HRD description.

Economou, T.; DiDonna, P.

2013-03-01

200

High dose rate endobronchial brachytherapy using a new applicator  

Microsoft Academic Search

Background and purpose: To obtain adequate spatial dose distribution for endobronchial brachytherapy, we applied reference dose points according to the bronchial diameter. For this purpose, we devised a new applicator of which the source transfer tube is contained in the center of the lumen for high dose rate (HDR) brachytherapy.Materials and methods: Thirty-nine patients with endobronchial cancer underwent endobronchial brachytherapy

Yoshihito Nomoto; Kazufusa Shouji; Shun Toyota; Masahiro Sasaoka; Shuuichi Murashima; Maki Ooi; Kan Takeda; Tsuyoshi Nakagawa

1997-01-01

201

High-strain-rate behavior of metal matrix composites  

Microsoft Academic Search

Dynamic loading response is an important design parameter, which is critical in severe applications where impact loading occurs, but which has been little investigated to date for MMCs. Those MMCs which have been tested at high strain-rates so far have been diverse in terms of matrix alloy and reinforcement type, size and shape, making comparisons difficult. In this study, four

Mustafa Guden

1997-01-01

202

Dosimetric investigation of high dose rate, gated IMRT  

SciTech Connect

Increasing the dose rate offers time saving for IMRT delivery but the dosimetric accuracy is a concern, especially in the case of treating a moving target. The objective of this work is to determine the effect of dose rate associated with organ motion and gated treatment using step-and-shoot IMRT delivery. Both measurements and analytical simulation on clinical plans are performed to study the dosimetric differences between high dose rate and low dose rate gated IMRT step-and-shoot delivery. Various sites of IMRT plans for liver, lung, pancreas, and breast cancers were delivered to a custom-made motorized phantom, which simulated sinusoidal movement. Repeated measurements were taken for gated and nongated delivery with different gating settings and three dose rates, 100, 500, and 1000 MU/min using ion chambers and extended dose range films. For the study of the residual motion effect for individual segment dose and composite dose of IMRT plans, our measurements with 30%-60% phase gating and without gating for various dose rates were compared. A small but clinically acceptable difference in delivered dose was observed between 1000, 500, and 100 MU/min at 30%-60% phase gating. A simulation is presented, which can be used for predicting dose profiles for patient cases in the presence of motion and gating to confirm that IMRT step-and-shoot delivery with gating for 1000 MU/min are not much different from 500 MU/min. Based on the authors sample plan analyses, our preliminary results suggest that using 1000 MU/Min dose rate is dosimetrically accurate and efficient for IMRT treatment delivery with gating. Nonetheless, for the concern of patient care and safety, a patient specific QA should be performed as usual for IMRT plans for high dose rate deliveries.

Lin, Teh; Chen Yan; Hossain, Murshed; Li, Jinsheng; Ma, C.-M. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)

2008-11-15

203

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. A method for retrieving the cumulus entrainment rate from ground based observations  

E-print Network

Reproduced with permission of the copyright owner. Further reproduction prohibited without at Madison pg. n/a #12;Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. #12;Reproduced with permission of the copyright owner. Further reproduction prohibited

Wisconsin at Madison, University of

204

High production rate of IBAD-MgO buffered substrate  

NASA Astrophysics Data System (ADS)

The conventional IBAD (Ion Beam Assisted Deposition) process using fluorite materials yields low production rates, resulting in high production cost, which reduces the motivation for practical application in spite of its high quality. The IBAD process using rock salt materials, e.g. MgO, is well known as a strong candidate of practical application due to its potential of high production rate and high in-plane grain alignment. In this work, the IBAD-MgO process was investigated for a newly developed architecture of PLD (Pulsed Laser Deposition)-CeO 2/sputter-LMO (LaMnO 3)/IBAD-MgO/sputter-GZO (Gd 2Zr 2O 7)/Hastelloy TM to make long buffered metal tapes with high properties and a high production rate. The 50 m-long IBAD-MgO substrates with about 4° of ? ?CeO 2 in an XRD ? scan could be fabricated repeatedly. A GdBCO (GdBa 2Cu 3O x) layer deposited on the buffered substrate showed the minimum Ic value of 325 A/cm-w in a 41 m-long tape. Almost of the tape showed 500-600 A/cm-w of Ic value. The deposition time for the IBAD-MgO layer was 60 s which was about 2 orders of magnitude shorter than the conventional IBAD process. The production rate of 24 m/h was realized at the IBAD-MgO process to fabricate the GdBCO coated conductor with high Jc and Ic properties.

Yoshizumi, M.; Miyata, S.; Ibi, A.; Fukushima, H.; Yamada, Y.; Izumi, T.; Shiohara, Y.

2009-10-01

205

Vitreous bond CBN high speed and high material removal rate grinding of ceramics  

SciTech Connect

High speed (up to 127 m/s) and high material removal rate (up to 10 mm{sup 3}/s/mm) grinding experiments using a vitreous bond CBN wheel were conducted to investigate the effects of material removal rate, wheel speed, dwell time and truing speed ratio on cylindrical grinding of silicon nitride and zirconia. Experimental results show that the high grinding wheel surface speed can reduce the effective chip thickness, lower grinding forces, enable high material removal rate grinding and achieve a higher G-ratio. The radial feed rate was increased to as high as 0.34 {micro}m/s for zirconia and 0.25 {micro}m/s for silicon nitride grinding to explore the advantage of using high wheel speed for cost-effective high material removal rate grinding of ceramics.

Shih, A.J.; Grant, M.B.; Yonushonis, T.M. [Cummins Engine Co., Inc., Columbus, IN (United States); Morris, T.O.; McSpadden, S.B. [Oak Ridge National Lab., TN (United States)

1998-08-01

206

Reproductive Hazards  

MedlinePLUS

... and female reproductive systems play a role in pregnancy. Problems with these systems can affect fertility and ... a reproductive hazard can cause different effects during pregnancy, depending on when she is exposed. During the ...

207

High-rate mechanical properties of energetic materials  

NASA Astrophysics Data System (ADS)

Compared to the many thousands of studies that have been performed on the energy release mechanisms of high energy materials, relatively few studies have been performed (a few hundred) into their mechanical properties. Since it is increasingly desired to model the high rate deformation of such materials, it is of great importance to gather data on their response so that predictive constitutive models can be constructed. This paper reviews the state of the art concerning what is known about the mechanical response of high energy materials. Examples of such materials are polymer bonded explosives (used in munitions), propellants (used to propel rockets), and pyrotechnics (used to initiate munitions and also in flares).

Walley, S. M.; Siviour, C. R.; Drodge, D. R.; Williamson, D. M.

2010-01-01

208

High rate sputter deposition of wear resistant tantalum coatings  

SciTech Connect

The refractory nature and high ductility of body centered cubic (bcc) phase tantalum makes it a suitable material for corrosion- and wear-resistant coatings on surfaces which are subjected to high stresses and harsh chemical and erosive environments. Sputter deposition can produce thick tantalum films but is prone to forming the brittle tetragonal beta phase of this material. Efforts aimed at forming thick bcc phase tantalum coatings in both flat plate and cylindrical geometries by high-rate triode sputtering methods are discussed. In addition to substrate temperature, the bcc-to-beta phase ratio in sputtered tantalum coatings is shown to be sensitive to other substrate surface effects.

Matson, D.W.; Merz, M.D.; McClanahan, E.D.

1991-11-01

209

High repetition rate plasma mirror device for attosecond science  

SciTech Connect

This report describes an active solid target positioning device for driving plasma mirrors with high repetition rate ultra-high intensity lasers. The position of the solid target surface with respect to the laser focus is optically monitored and mechanically controlled on the nm scale to ensure reproducible interaction conditions for each shot at arbitrary repetition rate. We demonstrate the target capabilities by driving high-order harmonic generation from plasma mirrors produced on glass targets with a near-relativistic intensity few-cycle pulse laser system operating at 1 kHz. During experiments, residual target surface motion can be actively stabilized down to 47?nm (root mean square), which ensures sub-300-as relative temporal stability of the plasma mirror as a secondary source of coherent attosecond extreme ultraviolet radiation in pump-probe experiments.

Borot, A.; Douillet, D.; Iaquaniello, G.; Lefrou, T.; Lopez-Martens, R. [Laboratoire d'Optique Appliquée, ENSTA-ParisTech, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)] [Laboratoire d'Optique Appliquée, ENSTA-ParisTech, CNRS, Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France); Audebert, P.; Geindre, J.-P. [Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex (France)] [Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex (France)

2014-01-15

210

High rate discharge studies of Li/SO2 cells  

NASA Astrophysics Data System (ADS)

Experimental D-size spirally-wound 3V 10 A-hr cells were used in the reported study. The cells were instrumented with four iron-constantan thermocouples. It was found that during a discharge of a thermally insulated cell, the greatest amount of heat builds up in the center of the cell. The heat build-up appears to be purely resistive in nature. Concerning the safe use of these cells, it has been demonstrated that at very high rates of discharge, e.g., 10 A, cells may vent violently and cause a fire. At this high rate of discharge, the internal cell temperature exceeded the melting point of the lithium anode which is in the form of an unsupported strip. Thus, contact of the highly reactive molten lithium with other reactive species in the cell is possible under these conditions and could result in a very exothermic chemical reaction.

Dallek, S.; Bis, R. F.; Bowers, F. M.

211

High repetition rate plasma mirror device for attosecond science.  

PubMed

This report describes an active solid target positioning device for driving plasma mirrors with high repetition rate ultra-high intensity lasers. The position of the solid target surface with respect to the laser focus is optically monitored and mechanically controlled on the nm scale to ensure reproducible interaction conditions for each shot at arbitrary repetition rate. We demonstrate the target capabilities by driving high-order harmonic generation from plasma mirrors produced on glass targets with a near-relativistic intensity few-cycle pulse laser system operating at 1 kHz. During experiments, residual target surface motion can be actively stabilized down to 47?nm (root mean square), which ensures sub-300-as relative temporal stability of the plasma mirror as a secondary source of coherent attosecond extreme ultraviolet radiation in pump-probe experiments. PMID:24517742

Borot, A; Douillet, D; Iaquaniello, G; Lefrou, T; Audebert, P; Geindre, J-P; Lopez-Martens, R

2014-01-01

212

Magnetic Implosion for Novel Strength Measurements at High Strain Rates  

SciTech Connect

Recently Lee and Preston have proposed to use magnetic implosions as a new method for measuring material strength in a regime of large strains and high strain rates inaccessible to previously established techniques. By its shockless nature, this method avoids the intrinsic difficulties associated with an earlier approach using high explosives. The authors illustrate how the stress-strain relation for an imploding liner can be obtained by measuring the velocity and temperature history of its inner surface. They discuss the physical requirements that lead us to a composite liner design applicable to different test materials, and also compare the code-simulated prediction with the measured data for the high strain-rate experiments conducted recently at LANL. Finally, they present a novel diagnostic scheme that will enable us to remove the background in the pyrometric measurement through data reduction.

Lee, H.; Preston, D.L.; Bartsch, R.R.; Bowers, R.L.; Holtkamp, D.; Wright, B.L.

1998-10-19

213

High rate constitutive modeling of aluminium alloy tube  

NASA Astrophysics Data System (ADS)

As the need for fuel efficient automobiles increases, car designers are investigating light-weight materials for automotive bodies that will reduce the overall automobile weight. Aluminium alloy tube is a desirable material to use in automotive bodies due to its light weight. However, aluminium suffers from lower formability than steel and its energy absorption ability in a crash event after a forming operation is largely unknown. As part of a larger study on the relationship between crashworthiness and forming processes, constitutive models for 3mm AA5754 aluminium tube were developed. A nominal strain rate of 100/s is often used to characterize overall automobile crash events, whereas strain rates on the order of 1000/s can occur locally. Therefore, tests were performed at quasi-static rates using an Instron test fixture and at strain rates of 500/s to 1500/s using a tensile split Hopkinson bar. High rate testing was then conducted at rates of 500/s, 1000/s and 1500/s at 21circC, 150circC and 300circC. The generated data was then used to determine the constitutive parameters for the Johnson-Cook and Zerilli-Armstrong material models.

Salisbury, C. P.; Worswick, M. J.; Mayer, R.

2006-08-01

214

High Strain Rate Characterisation of a Polymer Bonded Sugar  

NASA Astrophysics Data System (ADS)

The mechanical properties of a polymer bonded sugar consisting of 78% sugar crystals, of modal particle size 310 ?m, dispersed in an HTPB binder have been characterized in a split Hopkinson pressure bar system at a strain rate of 103 s-1 and temperatures from -100 to +20 °C. These high rate experiments were supplemented by further experiments in an Instron at 10-3 s-1. The material behavior is compared to that of other polymer bonded explosives and simulants. In order to further understand the structural deformation mechanisms specimens of both pristine material and that after Instron testing were examined using X-ray microtomography.

Laity, P. R.; Siviour, C. R.; Church, P. D.; Proud, W. G.

2006-07-01

215

Methane hydrates with a high capacity and a high formation rate promoted by biosurfactants.  

PubMed

Lignosulfonates, which are byproducts of the pulp and paper industry, can be used as promoters for the formation of methane hydrates with a high capacity up to 170 v/v and a high formation rate. PMID:23073027

Wang, Weixing; Huang, Zhan; Chen, Haoran; Tan, Zhuyan; Chen, Caixing; Sun, Luyi

2012-12-11

216

A high-rate PCI-based telemetry processor system  

NASA Astrophysics Data System (ADS)

The high performances reached by the Satellite on-board telemetry generation and transmission, as consequently, will impose the design of ground facilities with higher processing capabilities at low cost to allow a good diffusion of these ground station. The equipment normally used are based on complex, proprietary bus and computing architectures that prevent the systems from exploiting the continuous and rapid increasing in computing power available on market. The PCI bus systems now allow processing of high-rate data streams in a standard PC-system. At the same time the Windows NT operating system supports multitasking and symmetric multiprocessing, giving the capability to process high data rate signals. In addition, high-speed networking, 64 bit PCI-bus technologies and the increase in processor power and software, allow creating a system based on COTS products (which in future may be easily and inexpensively upgraded). In the frame of EUCLID RTP 9.8 project, a specific work element was dedicated to develop the architecture of a system able to acquire telemetry data of up to 600 Mbps. Laben S.p.A - a Finmeccanica Company -, entrusted of this work, has designed a PCI-based telemetry system making possible the communication between a satellite down-link and a wide area network at the required rate.

Turri, R.

2002-07-01

217

High Pressure Burn Rate Measurements on an Ammonium Perchlorate Propellant  

SciTech Connect

High pressure deflagration rate measurements of a unique ammonium perchlorate (AP) based propellant are required to design the base burn motor for a Raytheon weapon system. The results of these deflagration rate measurements will be key in assessing safety and performance of the system. In particular, the system may experience transient pressures on the order of 100's of MPa (10's kPSI). Previous studies on similar AP based materials demonstrate that low pressure (e.g. P < 10 MPa or 1500 PSI) burn rates can be quite different than the elevated pressure deflagration rate measurements (see References and HPP results discussed herein), hence elevated pressure measurements are necessary in order understand the deflagration behavior under relevant conditions. Previous work on explosives have shown that at 100's of MPa some explosives will transition from a laminar burn mechanism to a convective burn mechanism in a process termed deconsolidative burning. The resulting burn rates that are orders-of-magnitude faster than the laminar burn rates. Materials that transition to the deconsolidative-convective burn mechanism at elevated pressures have been shown to be considerably more violent in confined heating experiments (i.e. cook-off scenarios). The mechanisms of propellant and explosive deflagration are extremely complex and include both chemical, and mechanical processes, hence predicting the behavior and rate of a novel material or formulation is difficult if not impossible. In this work, the AP/HTPB based material, TAL-1503 (B-2049), was burned in a constant volume apparatus in argon up to 300 MPa (ca. 44 kPSI). The burn rate and pressure were measured in-situ and used to calculate a pressure dependent burn rate. In general, the material appears to burn in a laminar fashion at these elevated pressures. The experiment was reproduced multiple times and the burn rate law using the best data is B = (0.6 {+-} 0.1) x P{sup (1.05{+-}0.02)} where B is the burn rate in mm/s and P is the pressure in units of MPa. Details of the experimental method, results and data analysis are discussed herein and briefly compared to other AP based materials that have been measured in this apparatus.

Glascoe, E A; Tan, N

2010-04-21

218

Modeling Large-Strain, High-Rate Deformation in Metals  

SciTech Connect

The large strain deformation response of 6061-T6 and Ti-6Al-4V has been evaluated over a range in strain rates from 10{sup -4} s{sup -1} to over 10{sup 4} s{sup -1}. The results have been used to critically evaluate the strength and damage components of the Johnson-Cook (JC) material model. A new model that addresses the shortcomings of the JC model was then developed and evaluated. The model is derived from the rate equations that represent deformation mechanisms active during moderate and high rate loading. Another model that accounts for the influence of void formation on yield and flow behavior of a ductile metal (the Gurson model) was also evaluated. The characteristics and predictive capabilities of these models are reviewed.

Lesuer, D R; Kay, G J; LeBlanc, M M

2001-07-20

219

Commercial optical inter-satellite communication at high data rates  

NASA Astrophysics Data System (ADS)

Laser communication terminals with data rates far above 1 Gbps have been in operation in orbit since January 2008, and the links established between two low Earth orbit (LEO) satellites have demonstrated error-free communication. Bit error rates better than 10-11 have been achieved without data encoding. Signal acquisition can be reproducibly achieved within a few seconds. After adaptation to larger link separation distances these laser communication terminals will be used in the low earth orbit-geosynchronous satellite (LEO-GEO) link of European data relay satellite (EDRS), the GEO European data relay system. LEO-to-ground and ground-to-LEO links have examined the impact of the atmosphere on such optical links. In the future, high data rate GEO-to-ground links will require ground stations equipped with adaptive optics, which are currently under development.

Gregory, Mark; Heine, Frank; Kämpfner, Hartmut; Lange, Robert; Lutzer, Michael; Meyer, Rolf

2012-03-01

220

Crystal growth rates of tricaprin and trilaurin under high pressures  

NASA Astrophysics Data System (ADS)

The effect of hydrostatic pressure on a linear crystal growth rate of tricaprin and trilaurin was investigated by the use of a capillary method in the pressure range up to 200 MPa. The undercooling temperature, ? T, was varied from 0.65 to 16 K. In order to investigate crystal growth kinetics of triacylglycerols, the melting temperature, density and viscosity were also measured under high pressures. The crystal growth rates of tricaprin and trilaurin decrease with increasing values of pressure applied. It was found that the crystal growth rate, v, can be expressed by the form v= A? Tn with n which can take large value in a range of small ? T value, whereas n decreases with increasing ? T value. From the comparison with several theories for the crystal growth from melts, the present result suggests that the two triacylglycerols freeze by the dislocation mechanism in the small ? T range and by the continuous mechanism in the large ? T range.

Yokoyama, Chiaki; Tamura, Yuichi; Nishiyama, Yoshiyuki

1998-08-01

221

High Efficiency and High Rate Deposited Amorphous Silicon-Based Solar Cells  

E-print Network

1 High Efficiency and High Rate Deposited Amorphous Silicon-Based Solar Cells PHASE I Annual Rate Deposition of Amorphous Silicon Films Using Hot-Wire CVD With Coil- Shaped Filament Section 5 Phase Diagram for Deposition of Amorphous and Microcrystalline Silicon #12;3 List of Figures Figure 2

Deng, Xunming

222

Dissolution rate of calcium carbonate in high pCO2 seawater under high pressure  

Microsoft Academic Search

To understand how the dissolution rate of calcium carbonate changes, laboratory experiments were conducted under high pressure and high pCO2 condition. As a result, rapid dissolution was observed at above 5000 ppm of pCO2. The initial dissolution rates of the well correlated with initial concentration of dissolved inorganic carbon. Dissolution rate were generally decreased with time. Dissolution of calcium carbonate

N. Tsurushima; M. Suzumura; N. Yamada; K. Harada

2008-01-01

223

Thermal, productive, and reproductive responses of high yielding cows exposed to short-term cooling in summer.  

PubMed

Effect of cooling on body temperature, milk production, estrous behavior, and reproductive performance was examined in 66 estrous-synchronized, Israeli-Holstein dairy cows. Cooling was by an automated system, which actuated sprinkling (30 s) followed by forced ventilation (4.5 min) for 30-min periods. Cows were cooled 9 times/d between 0500 and 2100 h over 10 d, starting 1 d before expected estrus until d 8 post estrus. Cooling reduced typical diurnal rise of body temperature in summer heat-stressed cows by .5 to .9 degrees C, and body temperature was maintained close to normothermic temperature (38.6 degrees C). Milk production of cooled cows was 2.6 kg/d (+8%) above control at end of the cooling period. More cooled cows than noncooled exhibited standing estrous behavior; in noncooled cows, silent ovulations or anestrus were more frequent. Conception rate of cooled cows did not differ from control, suggesting need for a longer than a 10-d cooling period for improvement of fertility. The cooling system has potential to alleviate heat stress in dairy cows and to improve their thermal balance, productive, and reproductive performances. PMID:3392302

Her, E; Wolfenson, D; Flamenbaum, I; Folman, Y; Kaim, M; Berman, A

1988-04-01

224

Optically Stimulated Luminescent Dosimetry for High Dose Rate Brachytherapy  

PubMed Central

Purpose: The objective was to determine whether optically stimulated luminescent dosimeters (OSLDs) were appropriate for in vivo measurements in high dose rate brachytherapy. In order to make this distinction, three dosimetric characteristics were tested: dose linearity, dose rate dependence, and angular dependence. The Landauer nanoDot™ OSLDs were chosen due to their popularity and their availability commercially. Methods: To test the dose linearity, each OSLD was placed at a constant location and the dwell time was varied. Next, in order to test the dose rate dependence, each OSLD was placed at different OLSD-to-source distances and the dwell time was held constant. A curved geometry was created using a circular Accuboost® applicator in order to test angular dependence. Results: The OSLD response remained linear for high doses and was independent of dose rate. For doses up to 600?cGy, the linear coefficient of determination was 0.9988 with a response of 725 counts per cGy. The angular dependence was significant only in “edge-on” scenarios. Conclusion: OSLDs are conveniently read out using commercially available readers. OSLDs can be re-read and serve as a permanent record for clinical records or be annealed using conventional fluorescent light. Lastly, OSLDs are produced commercially for $5 each. Due to these convenient features, in conjunction with the dosimetric performance, OSLDs should be considered a clinically feasible and attractive tool for in vivo HDR brachytherapy measurements. PMID:22888476

Tien, Christopher Jason; Ebeling, Robert; Hiatt, Jessica R.; Curran, Bruce; Sternick, Edward

2012-01-01

225

HIGH RATES OF EVOLUTION PRECEDED THE ORIGIN OF BIRDS  

PubMed Central

The origin of birds (Aves) is one of the great evolutionary transitions. Fossils show that many unique morphological features of modern birds, such as feathers, reduction in body size, and the semilunate carpal, long preceded the origin of clade Aves, but some may be unique to Aves, such as relative elongation of the forelimb. We study the evolution of body size and forelimb length across the phylogeny of coelurosaurian theropods and Mesozoic Aves. Using recently developed phylogenetic comparative methods, we find an increase in rates of body size and body size dependent forelimb evolution leading to small body size relative to forelimb length in Paraves, the wider clade comprising Aves and Deinonychosauria. The high evolutionary rates arose primarily from a reduction in body size, as there were no increased rates of forelimb evolution. In line with a recent study, we find evidence that Aves appear to have a unique relationship between body size and forelimb dimensions. Traits associated with Aves evolved before their origin, at high rates, and support the notion that numerous lineages of paravians were experimenting with different modes of flight through the Late Jurassic and Early Cretaceous. PMID:24471891

Puttick, Mark N; Thomas, Gavin H; Benton, Michael J; Polly, P David

2014-01-01

226

High rates of evolution preceded the origin of birds.  

PubMed

The origin of birds (Aves) is one of the great evolutionary transitions. Fossils show that many unique morphological features of modern birds, such as feathers, reduction in body size, and the semilunate carpal, long preceded the origin of clade Aves, but some may be unique to Aves, such as relative elongation of the forelimb. We study the evolution of body size and forelimb length across the phylogeny of coelurosaurian theropods and Mesozoic Aves. Using recently developed phylogenetic comparative methods, we find an increase in rates of body size and body size dependent forelimb evolution leading to small body size relative to forelimb length in Paraves, the wider clade comprising Aves and Deinonychosauria. The high evolutionary rates arose primarily from a reduction in body size, as there were no increased rates of forelimb evolution. In line with a recent study, we find evidence that Aves appear to have a unique relationship between body size and forelimb dimensions. Traits associated with Aves evolved before their origin, at high rates, and support the notion that numerous lineages of paravians were experimenting with different modes of flight through the Late Jurassic and Early Cretaceous. PMID:24471891

Puttick, Mark N; Thomas, Gavin H; Benton, Michael J

2014-05-01

227

Plastic behavior of aluminum in high strain rate regime  

NASA Astrophysics Data System (ADS)

The aim of this experiment was to study the plastic response of Al to dynamic loading at high strain rates. Dynamic loading was applied by direct laser ablation of the sample with pulse width of 3 ns long. The free surface velocity histories of shock loaded samples, 60-310 ?m thick at room temperature, and 150 ?m thick with initial temperature from 293 to 893 K, have been recorded using a line velocity interferometer for any reflections (VISAR) system. The line VISAR could measure free surface velocity profile with high temporal resolution (˜100 ps). The measured amplitudes of the elastic precursor waves have been approximated by power functions of the propagation distance with the power index of 0.581, and these data have been converted into relationships between the shear stress at Hugoniot elastic limit and the initial plastic strain rate. The peak longitudinal elastic stress and the strain rate meet a power law dependency with the power index of 0.44. Samples were recovered for post-shot metallographic analysis. The metallographic analysis leads to the conclusion that the spall strength of preheated aluminum is determined more by the rate of void nucleation rather than its growth.

Shu, Hua; Fu, Sizu; Huang, Xiuguang; Pan, Hao; Zhang, Fan; Xie, Ziyong; Ye, Junjian; Jia, Guo

2014-07-01

228

High-repetition-rate ferroelectric-cathode gyrotron  

NASA Astrophysics Data System (ADS)

The intensive research on ferroelectric electron-emission mechanisms in the last decade has resulted in a wide understanding of the physics and characteristics of this plasma-assisted electron source. Nevertheless, practical devices employing this cathode were hardly introduced. In this experimental study, a high-repetition-rate microwave oscillator based on a ferroelectric electron gun has been developed. The device operates as a cyclotron-resonance maser in the gyrotron mode. Microwave pulses exceeding 1.5 kW at ˜7 GHz are measured in repetition rates above 3 MHz and duty cycles of ˜50%. These experimental results encourage the implementation of ferroelectric cathodes in practical high-power microwave tubes.

Einat, M.; Jerby, E.; Rosenman, G.

2001-12-01

229

Development of VRLA batteries for high rate discharge applications  

NASA Astrophysics Data System (ADS)

During high-rate discharge, there is less utilization of the sealed, valve-regulated lead/acid VRSLA batteries because the secondary current distribution is less uniform and there is less time for ion diffusion. This study investigated the effects of positive plates' material porosity, positive/negative active material ratio, and electrode stacking pressure on cell performance during high-rate discharge. According to the experimental results, the cells with a porosity of 74-76% and positive/negative active material ratio of 1.2-1.5 exhibited the best cell performance. Cells with higher electrode stacking pressure exhibited higher initial capacity and average capacity per cycle with lower capacity loss per cycle.

Chen, Jenn-Shing

230

Evaluation of high data rate disk drive recording subsystem  

NASA Astrophysics Data System (ADS)

An effort has been made to evaluate disk drive components at high data rates. Fully functional write-head/media components to 2.6 Gbit/s have been demonstrated in spin-stand testing and magnetic force microscopy characterizations. In addition, the drive front-end electronics examined possess complete functionality up to 4.0 Gbit/s without significant performance degradation, which is consistent with electric modeling results. Furthermore, our experimental data clearly indicate that the pre-amp's performance at high frequency is becoming a limiting factor to achieving an ultrahigh data rate in present write-head/media designs. The magnetic moment on write gap edges for certain recording heads shows signs of becoming insensitive to following the write current switching speed at ultrahigh frequency.

Kaiser, David; Dakroub, Housan; van der Schans, Al; Haftek, Elzbieta; Li, Shaoping; Zhu, Wenzhong; Pro, John; Vorasarn, Ko; Stankiewick, Andrzej; Cox, Richard; Liu, Yan; Zhang, Huaan; Radish, Karstan W.; Klarquest, Sharma, Sarit; Champion, Eric

2003-05-01

231

Failure Rate Data Analysis for High Technology Components  

SciTech Connect

Understanding component reliability helps designers create more robust future designs and supports efficient and cost-effective operations of existing machines. The accelerator community can leverage the commonality of its high-vacuum and high-power systems with those of the magnetic fusion community to gain access to a larger database of reliability data. Reliability studies performed under the auspices of the International Energy Agency are the result of an international working group, which has generated a component failure rate database for fusion experiment components. The initial database work harvested published data and now analyzes operating experience data. This paper discusses the usefulness of reliability data, describes the failure rate data collection and analysis effort, discusses reliability for components with scarce data, and points out some of the intersections between magnetic fusion experiments and accelerators.

L. C. Cadwallader

2007-07-01

232

Adapting high-rate anaerobic treatment to Middle East conditions  

Microsoft Academic Search

High-rate anaerobic technologies offer cost-effective solutions for sewage treatment in the Middle East and Palestine in particular. The sewage characteristics in Palestine are quite different from the values elsewhere and show solids contents of more than 1000 mg chemical oxygen demand (COD)ss\\/L and total COD values exceeding 2000 mg\\/L. While summer temperatures exceed 25 °C, temperatures may drop to below

N. A. Mahmoud; G. Zeeman; Lier van J. B

2008-01-01

233

Adapting High-rate Anaerobic Treatment to Middle East Conditions  

Microsoft Academic Search

High-rate anaerobic technologies offer cost-effective solutions for sewage treatment in the Middle East and Palestine in particular.\\u000a The sewage characteristics in Palestine are quite different from the values elsewhere and show solids contents of more than\\u000a 1000 mg chemical oxygen demand (COD)ss\\/L and total COD values exceeding 2000 mg\\/L. While summer temperatures exceed 25 °C,\\u000a temperatures may drop to below

Nidal Mohmoud; Grietje Zeeman; Jules B. van Lier

234

Operation of a high repetition rate intense ion beam diode  

Microsoft Academic Search

Summary form only given, as follows. A magnetically insulated diode has been developed that is capable of pulsing at a high repetition rate for short bursts. This diode has a plasma-anode ion source which originates as an annular puff of H2 or some other gas. The gas puff is preionized and then inductively broken down by a 1 ?s-risetime magnetic

W. A. Noonan; S. C. Glidden; J. B. Greenly; D. A. Hammer; L. Brissette

1990-01-01

235

Dropout Prevention: Strategies for Improving High School Graduation Rates  

ERIC Educational Resources Information Center

The reason that the school dropout crisis is now referred to as a "silent epidemic" is because, when we weren't paying attention, the graduation rate in our country slipped to a level that threatens the very health and well-being of our society. Each year, almost one-third of all public high school students--and nearly one-half of all blacks,…

Owen, Jenni, Ed.; Rosch, Joel, Ed.; Muschkin, Clara, Ed.; Alexander, Jana, Ed.; Wyant, Casey, Ed.

2008-01-01

236

Feature processing during high-rate auditory selective attention  

Microsoft Academic Search

Auditory event-related brain potentials (ERPs) and reaction times were, analyzed in a selective attention task in which subjects\\u000a attended to tone pips presented at high rates-Xinterstimulua intervals [ISIs] of 40-200 msec). Subjects responded to infrequent\\u000a target tones of a specified frequency (250 or 4000 Hz) and location (left or right ear) that were louder than otherwise identical\\u000a tones presented randomly

David L. Woods; Claude Alain

1993-01-01

237

Avalanche Photo-Detection for High Data Rate Applications  

E-print Network

Avalanche photo detection is commonly used in applications which require single photon sensitivity. We examine the limits of using avalanche photo diodes (APD) for characterising photon statistics at high data rates. To identify the regime of linear APD operation we employ a ps-pulsed diode laser with variable repetition rates between 0.5MHz and 80MHz. We modify the mean optical power of the coherent pulses by applying different levels of well-calibrated attenuation. The linearity at high repetition rates is limited by the APD dead time and a non-linear response arises at higher photon-numbers due to multiphoton events. Assuming Poissonian input light statistics we ascertain the effective mean photon-number of the incident light with high accuracy. Time multiplexed detectors (TMD) allow to accomplish photon- number resolution by photon chopping. This detection setup extends the linear response function to higher photon-numbers and statistical methods may be used to compensate for non-linearity. We investigated this effect, compare it to the single APD case and show the validity of the convolution treatment in the TMD data analysis.

H. B. Coldenstrodt-Ronge; C. Silberhorn

2007-09-19

238

Frequent sexual reproduction and high intraspecific variation in Salix arctica: Implications for a terrestrial feedback to climate change in the High Arctic  

NASA Astrophysics Data System (ADS)

Genetic variation at molecular loci may underlie important variation in the phenotypes of arctic plants. Such intraspecific variation may be a neglected but important component of biological diversity in the Arctic that could impact how arctic ecosystems respond to climate change. Here, we characterized genetic and phenotypic variation in Salix arctica and evaluated the effect of S. arctica on ecosystem CO2 exchange, a process by which terrestrial ecosystems in the Arctic feedback to the global climate system. We found high genetic variation at microsatellite loci of S. arctica collected from an inland and a coastal site in Greenland that indicates sexual reproduction has occurred frequently as the ice sheet has retreated. Across the North American range of S. arctica, ten chloroplast DNA haplotypes were identified. Haplotype diversity and allelic richness were high overall and similar across regions with different glacial histories. Phenotypic variation in ecologically important traits varied substantially in a High Arctic population of S. arctica. In a widespread High Arctic ecosystem, a net loss of CO2 to the atmosphere was observed except where S. arctica was present. We suggest that high genetic variation in S. arctica is in part a result of frequent sexual reproduction, and that the phenotypic variation we observed is likely to be at least partially genetic-based. This would enable a productive High Arctic species to adapt and potentially prosper as climate changes, and thus affect the terrestrial feedback of the Arctic to the climate system.

Steltzer, Heidi; Hufbauer, Ruth A.; Welker, Jeffery M.; Casalis, Maxime; Sullivan, Patrick F.; Chimner, Rodney

2008-09-01

239

Scapular chondrosarcomas have high rates of local recurrence and metastasis.  

PubMed

This is the first report of a large series of patients with scapular chondrosarcomas. The grade distributions, locations of the tumors in the scapula, surgical techniques, status of margins, chondrosarcoma subtypes, Enneking stages, adjuvant therapies, local recurrence rates, metastasis rates, and survival prognoses of patients with scapular chondrosarcoma were evaluated. Forty-seven patients treated between 1921 and 1999 were analyzed retrospectively. Grade 3 disease was significantly associated with a poorer survival prognosis when compared with Grades 1 or 2 disease. Patients with tumors smaller than 5 cm were treated mainly with partial scapulectomy, and patients with tumors larger than 5 cm often were treated with total scapulectomy. The survival prognoses of patients with intralesional resections at initial surgery showed a tendency toward poorer survival when compared with patients with wide resections at initial surgery. Metastasis and local recurrence (21.3% and 40.4%) were higher in scapular chondrosarcomas than rates reported for patients with general chondrosarcomas, and local recurrence or metastasis was associated with limited survival. The 5- and 15-year survival probabilities subsequent to diagnosis were 79% and 53%, respectively. The high rates of local recurrence and metastasis likely were caused by the difficult anatomic relationships encountered during scapular resections. This study shows the importance of wide margins which must be achieved to provide local disease control. PMID:15346079

Schneiderbauer, Michaela M; Blanchard, Charlene; Gullerud, Rachel; Harmsen, William S; Rock, Michael G; Shives, Thomas C; Sim, Franklin H; Scully, Sean P

2004-09-01

240

Simulating subhaloes at high redshift: merger rates, counts and types  

NASA Astrophysics Data System (ADS)

Galaxies are believed to be in one-to-one correspondence with simulated dark matter subhaloes. We use high-resolution N-body simulations of cosmological volumes to calculate the statistical properties of subhalo (galaxy) major mergers at high redshift (z = 0.6-5). We measure the evolution of the galaxy merger rate, finding that it is much shallower than the merger rate of dark matter host haloes at z > 2.5, but roughly parallels that of haloes at z < 1.6. We also track the detailed merger histories of individual galaxies and measure the likelihood of multiple mergers per halo or subhalo. We examine satellite merger statistics in detail: 15-35 per cent of all recently merged galaxies are satellites, and satellites are twice as likely as centrals to have had a recent major merger. Finally, we show how the differing evolution of the merger rates of haloes and galaxies leads to the evolution of the average satellite occupation per halo, noting that for a fixed halo mass, the satellite halo occupation peaks at z ~ 2.5.

Wetzel, Andrew R.; Cohn, J. D.; White, Martin

2009-05-01

241

Simulating Subhalos at High Redshift: Merger Rates, Counts, and Types  

E-print Network

Galaxies are believed to be in one-to-one correspondence with simulated dark matter subhalos. We use high-resolution N-body simulations of cosmological volumes to calculate the statistical properties of subhalo (galaxy) major mergers at high redshift (z=0.6-5). We measure the evolution of the galaxy merger rate, finding that it is much shallower than the merger rate of dark matter host halos at z>2.5, but roughly parallels that of halos at ztrack the detailed merger histories of individual galaxies and measure the likelihood of multiple mergers per halo or subhalo. We examine satellite merger statistics in detail: 15%-35% of all recently merged galaxies are satellites and satellites are twice as likely as centrals to have had a recent major merger. Finally, we show how the differing evolution of the merger rates of halos and galaxies leads to the evolution of the average satellite occupation per halo, noting that for a fixed halo mass, the satellite halo occupation peaks at z~2.5.

Andrew R. Wetzel; J. D. Cohn; Martin White

2008-10-15

242

Sex-specific survival rates of adult roseate terns: are males paying a higher reproductive cost than females?  

USGS Publications Warehouse

A long-term mark-recapture/resighting program has been carried out on the Roseate Terns (Sterna dougallii) nesting at Falkner Island, Connecticut, USA from the late 1980s through the mid 2000s, and from 1995-1998 an intensive collaborative study of food-provisioning of chicks by their parents also was conducted on many of the banded individuals at this site. Adult female Roseate Terns have significantly higher 'local survival' rates than do males. While both sexes feed their young, males usually have higher prey delivery rates than do females and do most feeding of the (oldest if more than one) chick just before it fledges. Males usually depart at the same time as the (oldest) fledgling, while successful females parents may linger at the colony site for up to two weeks. The lower 'local survival' rate of males probably does not represent lower colony-site fidelity, but instead may reflect the price they pay for doing more 'child care,' especially if fledglings are still dependant on them for food during post breeding dispersal and (at least early) migration.

Spendelow, J.A.; Shealer, D.A.; Hatfield, J.S.; Nichols, J.D.; Nisbet, I.C.T.

2005-01-01

243

High rate ECR etching of III-V nitride materials  

SciTech Connect

The III-V nitride compound semiconductors are attracting considerable attention for blue and ultraviolet light emitting diodes (LEDs) and lasers as well as high temperature electronics due to their wide band gaps and high dielectric constants. The recent progress observed in the growth of these materials has not been matched by progress in processing techniques to fabricate more highly sophisticated devices. Patterning these materials has been especially difficult due to the relatively inert chemical nature of the group-III nitrides. The authors review dry etch techniques which have been used to pattern these materials including electron cyclotron resonance (ECR), reactive ion etch (RIE), and chemically assisted ion beam etching (CAIBE). ECR etch rates greater than 3,800 {angstrom}/min for InN, 3,500 {angstrom}/min for GaN, and 1,170 A/min for AlN are reported. Etch anisotropy, surface morphology, and near-surface stoichiometry will be discussed.

Shul, R.J.; Howard, A.J.; Kilcoyne, S.P. [Sandia National Labs., Albuquerque, NM (United States); Pearton, S.J.; Abernathy, C.R.; Vartuli, C.B. [Univ. of Florida, Gainesville, FL (United States); Barnes, P.A.; Bozack, M.J. [Auburn Univ., AL (United States)

1994-12-31

244

Montana High School Completion and Graduation Rates for the Graduating Class of 2003  

ERIC Educational Resources Information Center

This report details the graduation rates for the class of 2003 for Montana High Schools. Sections include: Montana High School Completion and Graduation Rate Overview, and Montana High School Completion and Graduation Rates, 2002-03 School Year.

McCulloch, Linda

2004-01-01

245

Analysis of the strain-rate sensitivity at high strain rates in FCC and BCC metals  

SciTech Connect

The development of a constitutive model based on the use of internal state variables and phenomenological models describing glide kinetics is reviewed. Application of the model to the deformation of fcc metals and alloys is illustrated, with an emphasis on the behavior at high strain rates. Preliminary results in pure iron and 4340 steel are also presented. Deformation twinning is observed in iron samples deformed in the Hopkinson pressure bar. The influence of twinning on the proposed constitutive is discussed. 11 refs., 8 figs.

Follansbee, P.S.

1988-01-01

246

Sexual reproduction in Hawaiian Acropora  

NASA Astrophysics Data System (ADS)

Sexual reproductive maturity was evaluated in Acropora valida, Acropora cytherea and Acropora humilis at French Frigate Shoals, Northwest Hawaiian Islands during two consecutive summers. Acropora valida gonads matured at different rates in different habitats in both years. Spawning was inferred by the sudden disappearance of gonads of mature size. Histological sections of fertile polyps confirmed the maturity of gonads prior to spawning. An isolated colony of A. humilis spawned in early summer. Strong indications of sexually mature colonics of A. cytherea exist, but clear temporal patterns were not apparent. Lunar period of spawning in reef flat A. valida and A. humilis differed from that reported for these species from other regions. The three species did not overlap in time of spawning. Previous ideas concerning the allochthonous origin of larval recruits, as well as the absence of Acropora from high islands of the Hawaiian chain, are re-evaluated in light of new evidence for sexual reproductive capacity by native populations.

Kenyon, Jean C.

1992-04-01

247

Multianode cylindrical proportional counter for high count rates  

DOEpatents

A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (< 60 keV) at count rates of greater than 10/sup 5/ counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

Hanson, J.A.; Kopp, M.K.

1980-05-23

248

Homogeneous Nucleation Rate for Highly Supercooled Cirrus Cloud Droplets.  

NASA Astrophysics Data System (ADS)

A mixed-phase hydrometer growth model has been applied to determining the nucleation mode and rate responsible for the glaciation of a highly supercooled liquid cloud studied jointly by ground-based polarization lidar and aircraft in situ probes. The cloud droplets were detected at the base of an orographically induced cirrus cloud at temperatures between 34.3° and 37.3°C. The vertical distribution above cloud base of two independent data quantities, the aircraft-measured water and ice particle concentrations and the lidar linear depolarization ratio, have been compared to model predictions for both the homogeneous and heterogeneous drop-freezing. modes. It is concluded that, although activated ice nuclei may have contributed to the glaciation of the cloud, homogeneous nucleation was the dominant mode. Accordingly, a homogeneous nucleation rate 106 times greater than that predicted by classical theory, but 103 times less than laboratory measurements would suggest is found to be appropriate at the measured cloud temperatures.

Sassen, Kenneth; Dodd, Gregory C.

1988-04-01

249

High rate 4. pi. beta. -. gamma. coincidence counting system  

SciTech Connect

A high count rate 4..pi.. ..beta..-..gamma.. coincidence counting system for the determination of absolute disintegration rates of short half-life radionuclides is described. With this system the dead time per pulse is minimized by not stretching any pulses beyond the width necessary to satisfy overlap coincidence requirements. The equations used to correct for the ..beta.., ..gamma.., and coincidence channel dead times and for accidental coincidences are presented but not rigorously developed. Experimental results are presented for a decaying source of /sup 56/Mn initially at 2 x 10/sup 6/ d/s and a set of /sup 60/Co sources of accurately known source strengths varying from 10/sup 3/ to 2 x 10/sup 6/ d/s. A check of the accidental coincidence equation for the case of two independent sources with varying source strengths is presented.

Johnson, L.O.; Gehrke, R.J.

1978-01-01

250

Fast demographic traits promote high diversification rates of Amazonian trees.  

PubMed

The Amazon rain forest sustains the world's highest tree diversity, but it remains unclear why some clades of trees are hyperdiverse, whereas others are not. Using dated phylogenies, estimates of current species richness and trait and demographic data from a large network of forest plots, we show that fast demographic traits--short turnover times--are associated with high diversification rates across 51 clades of canopy trees. This relationship is robust to assuming that diversification rates are either constant or decline over time, and occurs in a wide range of Neotropical tree lineages. This finding reveals the crucial role of intrinsic, ecological variation among clades for understanding the origin of the remarkable diversity of Amazonian trees and forests. PMID:24589190

Baker, Timothy R; Pennington, R Toby; Magallon, Susana; Gloor, Emanuel; Laurance, William F; Alexiades, Miguel; Alvarez, Esteban; Araujo, Alejandro; Arets, Eric J M M; Aymard, Gerardo; de Oliveira, Atila Alves; Amaral, Iêda; Arroyo, Luzmila; Bonal, Damien; Brienen, Roel J W; Chave, Jerome; Dexter, Kyle G; Di Fiore, Anthony; Eler, Eduardo; Feldpausch, Ted R; Ferreira, Leandro; Lopez-Gonzalez, Gabriela; van der Heijden, Geertje; Higuchi, Niro; Honorio, Eurídice; Huamantupa, Isau; Killeen, Tim J; Laurance, Susan; Leaño, Claudio; Lewis, Simon L; Malhi, Yadvinder; Marimon, Beatriz Schwantes; Marimon Junior, Ben Hur; Monteagudo Mendoza, Abel; Neill, David; Peñuela-Mora, Maria Cristina; Pitman, Nigel; Prieto, Adriana; Quesada, Carlos A; Ramírez, Fredy; Ramírez Angulo, Hirma; Rudas, Agustin; Ruschel, Ademir R; Salomão, Rafael P; de Andrade, Ana Segalin; Silva, J Natalino M; Silveira, Marcos; Simon, Marcelo F; Spironello, Wilson; ter Steege, Hans; Terborgh, John; Toledo, Marisol; Torres-Lezama, Armando; Vasquez, Rodolfo; Vieira, Ima Célia Guimarães; Vilanova, Emilio; Vos, Vincent A; Phillips, Oliver L

2014-05-01

251

Fast demographic traits promote high diversification rates of Amazonian trees  

PubMed Central

The Amazon rain forest sustains the world's highest tree diversity, but it remains unclear why some clades of trees are hyperdiverse, whereas others are not. Using dated phylogenies, estimates of current species richness and trait and demographic data from a large network of forest plots, we show that fast demographic traits – short turnover times – are associated with high diversification rates across 51 clades of canopy trees. This relationship is robust to assuming that diversification rates are either constant or decline over time, and occurs in a wide range of Neotropical tree lineages. This finding reveals the crucial role of intrinsic, ecological variation among clades for understanding the origin of the remarkable diversity of Amazonian trees and forests. PMID:24589190

Baker, Timothy R; Pennington, R Toby; Magallon, Susana; Gloor, Emanuel; Laurance, William F; Alexiades, Miguel; Alvarez, Esteban; Araujo, Alejandro; Arets, Eric J M M; Aymard, Gerardo; de Oliveira, Atila Alves; Amaral, Iêda; Arroyo, Luzmila; Bonal, Damien; Brienen, Roel J W; Chave, Jerome; Dexter, Kyle G; Di Fiore, Anthony; Eler, Eduardo; Feldpausch, Ted R; Ferreira, Leandro; Lopez-Gonzalez, Gabriela; van der Heijden, Geertje; Higuchi, Niro; Honorio, Eurídice; Huamantupa, Isau; Killeen, Tim J; Laurance, Susan; Leaño, Claudio; Lewis, Simon L; Malhi, Yadvinder; Marimon, Beatriz Schwantes; Marimon Junior, Ben Hur; Monteagudo Mendoza, Abel; Neill, David; Peñuela-Mora, Maria Cristina; Pitman, Nigel; Prieto, Adriana; Quesada, Carlos A; Ramírez, Fredy; Ramírez Angulo, Hirma; Rudas, Agustin; Ruschel, Ademir R; Salomão, Rafael P; de Andrade, Ana Segalin; Silva, J Natalino M; Silveira, Marcos; Simon, Marcelo F; Spironello, Wilson; ter Steege, Hans; Terborgh, John; Toledo, Marisol; Torres-Lezama, Armando; Vasquez, Rodolfo; Vieira, Ima Célia Guimarães; Vilanova, Emilio; Vos, Vincent A; Phillips, Oliver L; Wiens, John

2014-01-01

252

Modular high frame rate detector for synchrotron applications  

SciTech Connect

The development of detectors often lags the development in X-ray sources. However, advanced detectors are critical for fully utilizing and exploiting the capabilities of the new bright sources. We report on the development of a modular high frame rate detector for synchrotron applications such as small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS). The detector consists of four modules, each providing an imaging area of 5 x 5 cm{sup 2} and capable of frame rates of 200 frames per second (fps) with full resolution, and 650 fps with smaller region of interest (ROI). Details of the detector design and experiments at synchrotron beamlines are discussed in the paper.

Singh, B.; Yang, L.; Thacker, S.; Gaysinskly, V.; Guo, L.; et. al.

2011-01-27

253

High Temperatures Result in Smaller Nurseries which Lower Reproduction of Pollinators and Parasites in a Brood Site Pollination Mutualism  

PubMed Central

In a nursery pollination mutualism, we asked whether environmental factors affected reproduction of mutualistic pollinators, non-mutualistic parasites and seed production via seasonal changes in plant traits such as inflorescence size and within-tree reproductive phenology. We examined seasonal variation in reproduction in Ficus racemosa community members that utilise enclosed inflorescences called syconia as nurseries. Temperature, relative humidity and rainfall defined four seasons: winter; hot days, cold nights; summer and wet seasons. Syconium volumes were highest in winter and lowest in summer, and affected syconium contents positively across all seasons. Greater transpiration from the nurseries was possibly responsible for smaller syconia in summer. The 3–5°C increase in mean temperatures between the cooler seasons and summer reduced fig wasp reproduction and increased seed production nearly two-fold. Yet, seed and pollinator progeny production were never negatively related in any season confirming the mutualistic fig–pollinator association across seasons. Non-pollinator parasites affected seed production negatively in some seasons, but had a surprisingly positive relationship with pollinators in most seasons. While within-tree reproductive phenology did not vary across seasons, its effect on syconium inhabitants varied with season. In all seasons, within-tree reproductive asynchrony affected parasite reproduction negatively, whereas it had a positive effect on pollinator reproduction in winter and a negative effect in summer. Seasonally variable syconium volumes probably caused the differential effect of within-tree reproductive phenology on pollinator reproduction. Within-tree reproductive asynchrony itself was positively affected by intra-tree variation in syconium contents and volume, creating a unique feedback loop which varied across seasons. Therefore, nursery size affected fig wasp reproduction, seed production and within-tree reproductive phenology via the feedback cycle in this system. Climatic factors affecting plant reproductive traits cause biotic relationships between plants, mutualists and parasites to vary seasonally and must be accorded greater attention, especially in the context of climate change. PMID:25521512

Krishnan, Anusha; Pramanik, Gautam Kumar; Revadi, Santosh V.; Venkateswaran, Vignesh; Borges, Renee M.

2014-01-01

254

Identification of apoptotic cells in the thymus of piglets infected with highly pathogenic porcine reproductive and respiratory syndrome virus.  

PubMed

Porcine reproductive and respiratory syndrome (PRRS) is an immunosuppressive disease that is characterized by respiratory distress and poor growth in piglets and by severe reproductive failure in sows. PRRS was first recognized in the 1990s in Europe and the United States. In 2006, highly pathogenic (HP)-PRRS caused enormous economic losses in China. Our previous studies demonstrated that the HP-PRRS virus (HP-PRRSV) induced the apoptosis of numerous thymocytes in infected piglets, leading to severe thymus atrophy. To further identify the subset of apoptotic cells in thymus of HP-PRRSV-infected piglets, different cell types, apoptotic cells, and HP-PRRSV were marked with the corresponding markers. Results of the colocalization demonstrated that the apoptotic cells were not infected by HP-PRRSV, and most of them were CD3(+) T cells. No apoptosis was observed in the epithelial cells, and only few CD14(+) cells were apoptotic. HP-PRRSV was only found in CD14(+) cells, and epithelial cells and CD3(+) cells were not infected by HP-PRRSV. This is the first study to report the apoptotic and infected cells in the thymuses of HP-PRRSV-infected piglets. PMID:24787009

Li, Yuming; Wang, Gang; Liu, Yonggang; Tu, Yabin; He, Yuli; Wang, Zhiyan; Han, Zifeng; Li, Li; Li, Aidong; Tao, Ye; Cai, Xuehui

2014-08-30

255

Animal Reproduction  

NSDL National Science Digital Library

This Topic in Depth takes a look at organizations and educational websites concerned with reproduction in humans and other animals. The Society for the Study of Reproduction (SSR) "is an association of scientists and physicians interested in research in reproduction. Some members are engaged in basic or applied research, while others perform clinical practice." The SSR website (1) contains downloadable copies of the SSR Newsletter; position statements; and information about meetings, awards, and the organization. The Society for Reproduction and Fertility (SRF) "is open to scientists and students worldwide, who work on any aspect of reproductive biology or fertility in man and animals." The SRF website (2) contains sections regarding News, Events, Jobs, Honours, and Grants. SRF makes downloadable copies of its newsletter available as well. The primary aim of the European Society of Human Reproduction & Embryology (ESHRE) "is to promote interest in, and understanding of, reproductive biology and medicine. It does this through facilitating research and subsequent dissemination of research findings in human reproduction and embryology to the general public, scientists, clinicians and patient associations; it also works to inform politicians and policy makers throughout Europe." The ESHRE site (3) contains information about activities, membership, publications, special interest groups, and jobs. The primary function of the Centre for Reproductive Biology in Uppsala (CRU) "is to increase the knowledge about reproduction in animals and humans by applying a more comprehensive view on reproductive biology." CRU is composed of scientists from both Uppsala University and the Swedish University of Agricultural Science. The CRU site (4) contains information about a number of publications, and contact information for CRU members. The Population Council is a nonprofit "organization that conducts biomedical, social science, and public health research." The "Council's reproductive biology and immunology program undertakes fundamental research in the reproductive sciences and immunological processes related to sexually transmitted infections, particularly HIV." This website (5) provides information about different aspects of the research program including Germ Cell Dynamics, Sperm Maturation, and Physiology of Sertoli Cells. From Dr. Michael Gregory of Clinton Community College, the next site (6) is a concise overview of animal reproduction which addresses important aspects of sexual reproduction, and male and female reproductive systems. The final site (7) contains lecture notes regarding avian reproduction from Dr. Gary Ritchison's Ornithology course at Eastern Kentucky University. The lecture notes are interspersed with some especially nice images and diagrams.

256

Multiple gestation as a marker of reproductive efficacy: learning from assisted reproductive technologies.  

PubMed

This study postulates that apart from the number of embryos transferred, women with multiple gestation represent a subgroup of highly fertile individuals, whose embryos implant with higher efficiency than women with single gestation. Furthermore, each embryo generated from these women has a higher chance of reaching full term. The objective of this study was to compare implantation rate with the outcome of pregnancy (up to week 20) in multiple gestations following assisted reproductive techniques. The study group comprised 162 women with multiple gestation after assisted reproduction, followed prospectively with at least three ultrasound examinations performed between weeks 5 and 20 after the last menstrual period. Control group A comprised 344 fertile women with spontaneous single pregnancy followed with transvaginal ultrasound. Control group B consisted of 317 infertile women conceiving with single gestation after assisted reproduction and followed prospectively as in the study group. Embryo implantation rate and spontaneous embryo/fetal reduction, either partial or total (abortion), were registered in each case. Overall implantation in women with multiple gestation was higher (54.6%) than in the corresponding controls (25.6%). Furthermore, spontaneous embryo/fetus reduction was similar in the study cases and in fertile women (12.6 and 10.8% respectively) and significantly smaller than in the control group B (20.8%). Women with high reproductive efficacy exposed to assisted reproductive techniques generate cohorts of good quality embryos, with a high chance of implantation and of reaching birth. PMID:14759302

Zegers-Hochschild, F; Bravo, M; Fernández, E; Fabres, C; Balmaceda, J P; Mackenna, A

2004-01-01

257

Characteristics of surgeons with high and low malpractice claims rates.  

PubMed Central

We studied the relationship of malpractice claims and the personal, educational, and practice characteristics of a sample of surgeons (n = 427). The surgeons were members of a physician-owned malpractice trust and represented all those who had fewer than 0.13 malpractice claims per year and those with more than 0.54 claims per year. Data are reported separately for orthopedic surgeons (148), obstetrician-gynecologists (115), and a mixed group of other surgeons (164). The last group included otolaryngologists, neurosurgeons, and general, vascular, thoracic, and plastic surgeons. We studied the relationship between the number of malpractice claims (ranging from no history of claims to those terminated from the trust because of high rates of claims) and the surgeon's personal, educational, and practice characteristics. The major differences were between the surgeons who were terminated because of a high number of claims and those with few or no claims. Terminated surgeons were less likely to have completed a fellowship, belong to a clinical faculty, be members of professional societies, be graduates of an American or Canadian medical school, have specialty board certification, or be in a group practice. The data also suggest that orthopedists with high numbers of claims may be less likely to have a religious affiliation or to have a registered nurse working in their office practice. These findings suggest that surgeons with lower claim rates may be more likely to manifest exemplary modes of professional peer relationships and responsible clinical behavior. PMID:9074337

Adamson, T E; Baldwin, D C; Sheehan, T J; Oppenberg, A A

1997-01-01

258

Diamond detector for high rate monitors of fast neutrons beams  

SciTech Connect

A fast neutron detection system suitable for high rate measurements is presented. The detector is based on a commercial high purity single crystal diamond (SDD) coupled to a fast digital data acquisition system. The detector was tested at the ISIS pulsed spallation neutron source. The SDD event signal was digitized at 1 GHz to reconstruct the deposited energy (pulse amplitude) and neutron arrival time; the event time of flight (ToF) was obtained relative to the recorded proton beam signal t{sub 0}. Fast acquisition is needed since the peak count rate is very high ({approx}800 kHz) due to the pulsed structure of the neutron beam. Measurements at ISIS indicate that three characteristics regions exist in the biparametric spectrum: i) background gamma events of low pulse amplitudes; ii) low pulse amplitude neutron events in the energy range E{sub dep}= 1.5-7 MeV ascribed to neutron elastic scattering on {sup 12}C; iii) large pulse amplitude neutron events with E{sub n} < 7 MeV ascribed to {sup 12}C(n,{alpha}){sup 9}Be and 12C(n,n')3{alpha}.

Giacomelli, L.; Rebai, M.; Cippo, E. Perelli; Tardocchi, M.; Fazzi, A.; Andreani, C.; Pietropaolo, A.; Frost, C. D.; Rhodes, N.; Schooneveld, E.; Gorini, G. [Dipartimento di Fisica, Universita degli Studi di Milano-Bicocca, and Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano (Italy); Energy Department, Politecnico di Milano, Milano (Italy); Dipartimento di Fisica, Centro NAST, Universita degli Studi di Roma Tor Vergata, Roma (Italy); STFC, ISIS facility, Rutherford Appleton Laboratory, Chilton Didcot Oxfordshire (United Kingdom); Dipartimento di Fisica, Universita degli Studi di Milano-Bicocca, and Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Milano (Italy)

2012-06-19

259

Handling high data rate detectors at Diamond Light Source  

NASA Astrophysics Data System (ADS)

An increasing number of area detectors, in use at Diamond Light Source, produce high rates of data. In order to capture, store and process this data High Performance Computing (HPC) systems have been implemented. This paper will present the architecture and usage for handling high rate data: detector data capture, large volume storage and parallel processing. The EPICS area Detector frame work has been adopted to abstract the detectors for common tasks including live processing, file format and storage. The chosen data format is HDF5 which provides multidimensional data storage and NeXuS compatibility. The storage system and related computing infrastructure include: a centralised Lustre based parallel file system, a dedicated network and a HPC cluster. A well defined roadmap is in place for the evolution of this to meet demand as the requirements and technology advances. For processing the science data the HPC cluster allow efficient parallel computing, on a mixture of ×86 and GPU processing units. The nature of the Lustre storage system in combination with the parallel HDF5 library allow efficient disk I/O during computation jobs. Software developments, which include utilising optimised parallel file reading for a variety of post processing techniques, are being developed in collaboration as part of the Pan-Data EU Project (www.pan-data.eu). These are particularly applicable to tomographic reconstruction and processing of non crystalline diffraction data.

Pedersen, U. K.; Rees, N.; Basham, M.; Ferner, F. J. K.

2013-03-01

260

Animal Reproduction  

NSDL National Science Digital Library

What animals abandon their offspring? Find out this and more as you explore reproduction in the animal world. Did you know that all animals must reproduce to survive? In this project you will be learning some interesting facts about reproduction in animals. After you have some background information you will have a chance to select 3 animals and complete a chart on reproduction. TASK: Day 1 ...

Mrs. Joggerst

2008-03-30

261

Reproduction in female reindeer.  

PubMed

Reindeer are either wild or kept under very extensive farming systems. They are seasonal breeders, with mating coinciding with the decreasing photoperiod in the autumn, and with calving in the spring. Little is known regarding the factors that influence reproduction in reindeer or of their reproductive physiology. Studies carried out to date have mainly focused on issues related to the population dynamics of wild populations and semi-domestic herds, and to a limited extent on the reproductive physiology of the female. Nor is much known about reproductive disorders and their medical treatment, or of the possibilities to manipulate or control reproduction by the use of hormones. Modern reproductive techniques such as artificial insemination and in vitro fertilisation, maturation and transfer of embryos have so far received scant attention.In the future, it is possible that reindeer under certain conditions might be kept in more intensive production systems. Limited access to high-quality winter pastures and increased demands for productivity have resulted in artificial feeding becoming a common practice in various reindeer herding areas in Scandinavia. In efforts to enhance the productivity of reindeer herds, attention has been focused on factors affecting reproduction in the female and survival of the offspring. Further knowledge on these issues seems necessary when developing strategies for optimalization of meat production in domestic herds and the harvesting of wild populations. This paper puts a broad focus on various aspects of reproduction, including factors influencing the fecundity of reproductively active females. In order to understand these effects it is important also to have a basic understanding of the reproductive physiology of these animals. PMID:10844224

Ropstad, E

2000-07-01

262

Proteomics and Comparative Genomic Investigations Reveal Heterogeneity in Evolutionary Rate of Male Reproductive Proteins in Mice (Mus domesticus)  

E-print Network

degree of compartmentalization, with at least six distinct tissue types contributing material species, we lack a comprehensive picture of the specific proteins produced by different accessory tissues with a high-quality human seminal fluid data set. We find that Gene Ontology functions of seminal proteins

Dean, Matthew D.

263

High-pulse-repetition-rate HF laser with plate electrodes  

SciTech Connect

A high-pulse-repetition-rate electric-discharge HF laser with inductive-capacitive discharge stabilisation in the active H{sub 2}-SF{sub 6}-He mixture is studied. The multisectional discharge gap with a total length of 250 mm is formed by pairs of anode-cathode plates arranged in a zigzag pattern. The width of the discharge gap between each pair of plates is {approx}1 mm and its height is {approx}12 mm. The laser-beam cross section at the output cavity mirror is {approx}9 mm x 11 mm. The maximum laser pulse energy and the maximum laser efficiency for the H{sub 2}-SF{sub 6} mixture are 14.3 mJ and 2.1%, respectively. The addition of He to the mixture reduced the laser pulse energy by 10%-15%. The maximum gas velocity in the gap between the electrodes achieves 20 m s{sup -1}. The limiting pulse repetition rate f{sub lim} for which a decrease in the laser pulse energy is still not observed is {approx}2kHz for the H{sub 2}-SF{sub 6} mixture and {approx}2.4kHz for the H{sub 2}-SF{sub 6}-He mixture. The average output power {approx}27 W is obtained for a pulse repetition rate of 2.4 kHz. (lasers)

Andramanov, A V; Kabaev, S A; Lazhintsev, B V; Nor-Arevyan, V A; Pisetskaya, A V; Selemir, Victor D [Russian Federal Nuclear Center 'All-Russian Scientific Research Institute of Experimental Physics', Sarov, Nizhnii Novgorod Region (Russian Federation)

2006-03-31

264

High renesting rates in arctic-breeding Dunlin (Calidris alpina): a clutch-removal experiment  

USGS Publications Warehouse

The propensity to replace a clutch is a complex component of avian reproduction and poorly understood. We experimentally removed clutches from an Arctic-breeding shorebird, the Dunlin (Calidris alpina arcticola), during early and late stages of incubation to investigate replacement clutch rates, renesting interval, and mate and site fidelity between nesting attempts. In contrast to other Arctic studies, we documented renesting by radiotracking individuals to find replacement clutches. We also examined clutch size and mean egg volume to document changes in individual females’ investment in initial and replacement clutches. Finally, we examined the influence of adult body mass, clutch volume, dates of clutch initiation and nest loss, and year on the propensity to renest. We found high (82–95%) and moderate (35–50%) rates of renesting for early and late incubation treatments. Renesting intervals averaged 4.7–6.8 days and were not different for clutches removed early or late in incubation. Most pairs remained together for renesting attempts. Larger females were more likely to replace a clutch; female body mass was the most important parameter predicting propensity to renest. Clutches lost later in the season were less likely to be replaced. We present evidence that renesting is more common in Arctic-breeding shorebirds than was previously thought, and suggest that renesting is constrained by energetic and temporal factors as well as mate availability. Obtaining rates of renesting in species breeding at different latitudes will help determine when this behavior is likely to occur; such information is necessary for demographic models that include individual and population-level fecundity estimates.

Gates, H. River; Lanctot, Richard B.; Powell, Abby N.

2013-01-01

265

High-order harmonic generation using a high-repetition-rate turnkey laser  

NASA Astrophysics Data System (ADS)

We generate high-order harmonics at high pulse repetition rates using a turnkey laser. High-order harmonics at 400 kHz are observed when argon is used as target gas. In neon, we achieve generation of photons with energies exceeding 90 eV (˜13 nm) at 20 kHz. We measure a photon flux of up to 4.4 × 1010 photons per second per harmonic in argon at 100 kHz. Many experiments employing high-order harmonics would benefit from higher repetition rates, and the user-friendly operation opens up for applications of coherent extreme ultra-violet pulses in new research areas.

Lorek, E.; Larsen, E. W.; Heyl, C. M.; Carlström, S.; Pale?ek, D.; Zigmantas, D.; Mauritsson, J.

2014-12-01

266

Parasitic heating effects in high frame rate laser imaging experiments  

NASA Astrophysics Data System (ADS)

The number of applications using high frame rate imaging in combustion research has grown rapidly in recent years. Enabled by continuous improvements in laser power, a wide range of diagnostics have been developed to measure velocity, species concentration, and temperature. Growing attention is focused on measurements near surfaces, e.g., to gain better insight into transient boundary layer flows in internal combustion engines. During such experiments, laser light is used to illuminate the gas phase region above the surface, but often the laser beam is terminated into the surface directly. Thus, laser operation at several kilohertz and power levels in the range of 10-100 W raise concerns about heating the surface and altering the conditions in the gas phase. In other words, the non-intrusive properties of laser diagnostics might not be guaranteed under such conditions. We have investigated the effect of heating by high repetition rate lasers by measuring the temperature of an exposed metal surface with an infrared sensor and by various simulation approaches. The current results show a modest but noticeable influence of laser heating.

Brusnahan, Matthew; Lu, Louise; Sick, Volker

2013-06-01

267

Final Report, Photocathodes for High Repetition Rate Light Sources  

SciTech Connect

This proposal brought together teams at Brookhaven National Laboratory (BNL), Lawrence Berkeley National Laboratory (LBNL) and Stony Brook University (SBU) to study photocathodes for high repetition rate light sources such as Free Electron Lasers (FEL) and Energy Recovery Linacs (ERL). The work done under this grant comprises a comprehensive program on critical aspects of the production of the electron beams needed for future user facilities. Our program pioneered in situ and in operando diagnostics for alkali antimonide growth. The focus is on development of photocathodes for high repetition rate Free Electron Lasers (FELs) and Energy Recovery Linacs (ERLs), including testing SRF photoguns, both normal-conducting and superconducting. Teams from BNL, LBNL and Stony Brook University (SBU) led this research, and coordinated their work over a range of topics. The work leveraged a robust infrastructure of existing facilities and the support was used for carrying out the research at these facilities. The program concentrated in three areas: a) Physics and chemistry of alkali-antimonide cathodes b) Development and testing of a diamond amplifier for photocathodes c) Tests of both cathodes in superconducting RF photoguns and copper RF photoguns

Ben-Zvi, Ilan [Stony Brook University

2014-04-20

268

A digital approach for real time high-rate high-resolution radiation measurements  

NASA Astrophysics Data System (ADS)

Modern spectrometers are currently developed by using digital pulse processing (DPP) systems, showing several advantages over traditional analog electronics. The aim of this work is to present digital strategies, in a time domain, for the development of real time high-rate high-resolution spectrometers. We propose a digital method, based on the single delay line (SDL) shaping technique, able to perform multi-parameter analysis with high performance even at high photon counting rates. A robust pulse shape and height analysis (PSHA), applied on single isolated time windows of the detector output waveforms, is presented. The potentialities of the proposed strategy are highlighted through both theoretical and experimental approaches. To strengthen our approach, the implementation of the method on a real-time system together with some experimental results are presented. X-ray spectra measurements with a semiconductor detector are performed both at low and high photon counting rates (up to 1.1 Mcps).

Gerardi, G.; Abbene, L.

2014-12-01

269

Ray-based and wavefront-based holographic displays for high-density light-field reproduction  

NASA Astrophysics Data System (ADS)

This paper introduces holographic 3D displays for ray-based and wavefront-based light-field reproductions. As a raybased display though a hard copy 3D image, a holographic 3D printer is introduced, which automatically outputs highresolution full-parallax holographic stereograms from 3D image data. Fine-quality full-color 3D images were experimentally obtained with excellent gloss and texture appearances. As a wavefront-based display, we have proposed a technique for calculating computer generated hologram, in which the wavefront is derived from the light-ray information. High-resolution display of deep 3D scene is possible, while realistic image can be generated by utilizing conventional rendering techniques for computer graphics.

Yamaguchi, Masahiro

2011-06-01

270

Reproductive ecology of female chimpanzees.  

PubMed

An important adaptive problem for mammals in general, and primates in particular, is how females can manage the high costs of reproduction in the face of fluctuating energetic supplies. For many species, the best solution is to breed seasonally such that high costs are temporally coincident with predictable periods of resource abundance. This is an unreliable strategy for some primates, such as chimpanzees (Pan troglodytes), for which large body size forces an increase in dietary complexity and prolonged reproductive efforts. Here, I review data on reproductive function in chimpanzees, a species that demonstrates a risk-averse reproductive strategy wherein reproductive investment is allocated in accordance with maternal condition. Life history parameters for chimpanzees indicate that most females produce very few surviving offspring. However, comparisons between captive and wild populations and within wild populations illustrate that variation in resource access leads to highly variable reproductive success. Focused hormonal studies have demonstrated these effects at a proximate level, with energetic influences on female dispersal, receptivity, cycle quality, conception success, and lactational amenorrhea. Downstream of these effects, female reproductive function affects sexual attractiveness, and by virtue of males' own optimal reproductive strategies, can lead to coercive aggression and decreased foraging efficiency. Because of their extreme reproductive costs, female chimpanzees utilize a highly conservative reproductive strategy, one that minimizes the costs of ecological variation but makes them vulnerable to sexual conflict and costs of sociality. PMID:23015287

Thompson, Melissa Emery

2013-03-01

271

High flow rate development: process optimization using megasonic immersion development (MID)  

NASA Astrophysics Data System (ADS)

In previous study the high impact of development by-products on Critical Dimension (CD) through the microloading effect has been demonstrated for a Novolak resist. In this paper, through further tests involving Chemically Amplified Resist (CAR) and Novolak resist, the microloading effect of development is characterized and tentative mechanism is presented. Megasonic Immersion Development (MID), a high flow rate development technique similar to the Proximity Gap Suction Development (PGSD), was used and compared with spin spray development and puddle development. On TOK IP3600, a Novolak resist, we have explored a wide range of process conditions with MID. Developer temperature was varied from 5°C to 40°C with TMAH developer concentration of 1.9% and 2.38% resulting in an isofocal dose range of 90mJ to 190mJ. Exposure Focus Matrix (EFM) with a specific microloading pattern and resist cross sections were performed. The best conditions are quite far from the standard process advised by the resist supplier. Very nice standing wave profile was obtained at high temperature development. On CAR, JEOL 9000MVII, a 50kV e-beam vector scan tool, and ETEC ALTA 4300, a DUV raster scan tool, were used with different develop process techniques including MID. FujiFilm Arch FEP-171 positive CAR and Sumitomo NEB-22 negative CAR were used on 50kV writing tool. Sumitomo PEK-130 was used on DUV writing tool. FEP-171 and PEK-1300 show microloading effect on high density patterns but not NEB-22. MID shows also improved reproduction of develop features in the chrome and a 20% improvement of CD uniformity. The results of this study seem to indicate that a closer look in their development process is needed for 90nm and 65nm technologies.

Courboin, Daniel; Choi, Jong Woo; Jung, Sang Hyun; Baek, Seung Hee; Kim, Lee Ju

2004-12-01

272

High Level of Divergence of Male-Reproductive-Tract Proteins, between Drosophila melanogaster and Its Sibling Species, D. simulans  

Microsoft Academic Search

We compared male-reproductive-tract polypeptides of Drosophila melanogaster and D. simulans by using two-dimensional gel electrophoresis. Approximately 64% of male-reproductive-tract polypeptides were identical between two randomly chosen isofemale lines from these two species, compared with 83% identity for third-instar imaginal wing-disc polypeptides. Qualitatively similar differences were found be- tween reproductive tracts and imaginal discs when D. sechellia was compared with D.

Rama S. Singh

273

Diversification and reproductive isolation: cryptic species in the only New World high-duty cycle bat, Pteronotus parnellii  

PubMed Central

Background Molecular techniques are increasingly employed to recognize the presence of cryptic species, even among commonly observed taxa. Previous studies have demonstrated that bats using high-duty cycle echolocation may be more likely to speciate quickly. Pteronotus parnellii is a widespread Neotropical bat and the only New World species to use high-duty cycle echolocation, a trait otherwise restricted to Old World taxa. Here we analyze morphological and acoustic variation and genetic divergence at the mitochondrial COI gene, the 7th intron region of the y-linked Dby gene and the nuclear recombination-activating gene 2, and provide extensive evidence that P. parnellii is actually a cryptic species complex. Results Central American populations form a single species while three additional species exist in northern South America: one in Venezuela, Trinidad and western Guyana and two occupying sympatric ranges in Guyana and Suriname. Reproductive isolation appears nearly complete (only one potential hybrid individual found). The complex likely arose within the last ~6 million years with all taxa diverging quickly within the last ~1-2 million years, following a pattern consistent with the geological history of Central and northern South America. Significant variation in cranial measures and forearm length exists between three of the four groups, although no individual morphological character can discriminate these in the field. Acoustic analysis reveals small differences (5–10 kHz) in echolocation calls between allopatric cryptic taxa that are unlikely to provide access to different prey resources but are consistent with divergence by drift in allopatric species or through selection for social recognition. Conclusions This unique approach, considering morphological, acoustic and multi-locus genetic information inherited maternally, paternally and bi-parentally, provides strong support to conclusions about the cessation of gene flow and degree of reproductive isolation of these cryptic species. PMID:23360354

2013-01-01

274

High-performance MCT LWIR and MWIR staring array for high-frame-rate applications  

Microsoft Academic Search

There is a great demand for staring arrays adapted to high frame rate applications. These applications cover military fields (seekers for example) and also commercial fields for process monitoring or surveillance. To answer this need MCT staring arrays offer a very wide range of possibilities covering different wavebands from MWIR to LWIR and operating at rather high FPA temperatures. In

Philippe Tribolet; Valery Compain; Raymond Boch

1996-01-01

275

Comparative analysis of apoptotic changes in peripheral immune organs and lungs following experimental infection of piglets with highly pathogenic and classical porcine reproductive and respiratory syndrome virus  

PubMed Central

Background Our previous studies have demonstrated that piglets infected with highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) may develop significant thymus atrophy, which related to thymocytes apoptosis. However, apart from that detected in the thymus, there are no reports describing cell apoptosis induced by HP-PRRSV infection. In this study, we analyzed comparatively the pathological changes, cell apoptosis and viral load in peripheral immune organs including tonsil, inguinal lymph nodes (ILNs) and spleen and lungs following experimental infection of piglets with HP-PRRSV HuN4 and classical PRRSV CH-1a. Findings HP-PRRSV HuN4 exhibited much stronger cell tropism than CH-1a in immune organs and lungs of piglets. HuN4 infection led to the serious injuries in tonsils, ILNs, spleens and lungs, especially apoptosis in these organs was significant. Conclusions HuN4 infection induced severe lesions (gross pathology, histopathology and cell apoptosis) in the peripheral immune organs and lungs of infected piglets. Large numbers of apoptotic cells in immune organs and lung induced by HuN4 may play a role in the pathogenesis of the HP-PRRS and the distinct injuries caused by HuN4 infection may be associated with the high mortality rate of HP-PRRS in pigs. PMID:24393149

2014-01-01

276

Advances in high-rate uncooled detector fabrication at Raytheon  

NASA Astrophysics Data System (ADS)

Over the past two years Raytheon has made a major investment aimed at establishing a high volume uncooled manufacturing capability. This effort has addressed three elements of the uncooled value stream, namely bolometer fabrication, packaging and calibration/test. To facilitate a low cost / high volume source of bolometers Raytheon has formed a partnership with a high volume 200mm commercial silicon wafer fabrication. Over a 12 month period Raytheon has installed 200mm VOx deposition equipment, matched the metrology used on the Raytheon 150mm line, transferred the process flow used to fabricate Raytheon's double layer bolometer process and qualified the product. In this paper we will review the process transfer methodology and bolometer performance. To reduce bolometer packaging cost and increase production rates, Raytheon has implemented an automated packaging line. This line utilizes automated adhesive dispense, component pick and place, wire bonding and solder seal. In this paper we will review the process flow, qualification process and line capacity Calibration and test has traditionally been performed using a number of temperature chambers, with increased throughput being obtained by adding more chambers. This comes at the expense of increased test labor required to feed the chambers and an increased energy and floor space foot print. To avoid these collateral costs, Raytheon has implemented an automated robotic calibration cell capable of performing in excess of 5,000 calibrations a month. In this paper we will provide an overview of the calibration cell along with takt time and throughput data.

Black, S. H.; Kraft, R.; Medrano, A.; Kocian, T.; Bradstreet, D.; Williams, R.; Yang, T.

2010-04-01

277

The strain-rate sensitivity of high-strength high-toughness steels.  

SciTech Connect

The present study examines the strain-rate sensitivity of four high strength, high-toughness alloys at strain rates ranging from 0.0002 s-1 to 200 s-1: Aermet 100, a modified 4340, modified HP9-4-20, and a recently developed Eglin AFB steel alloy, ES-1c. A refined dynamic servohydraulic method was used to perform tensile tests over this entire range. Each of these alloys exhibit only modest strain-rate sensitivity. Specifically, the strain-rate sensitivity exponent m, is found to be in the range of 0.004-0.007 depending on the alloy. This corresponds to a {approx}10% increase in the yield strength over the 7-orders of magnitude change in strain-rate. Interestingly, while three of the alloys showed a concominant {approx}3-10% drop in their ductility with increasing strain-rate, the ES1-c alloy actually exhibited a 25% increase in ductility with increasing strain-rate. Fractography suggests the possibility that at higher strain-rates ES-1c evolves towards a more ductile dimple fracture mode associated with microvoid coalescence.

Dilmore, M.F. (AFRL/MNMW, Eglin AFB, FL); Crenshaw, Thomas B.; Boyce, Brad Lee

2006-01-01

278

High frequency chest compression effects heart rate variability.  

PubMed

High frequency chest compression (HFCC) supplies a sequence of air pulses through a jacket worn by a patient to remove excessive mucus for the treatment or prevention of lung disease patients. The air pulses produced from the pulse generator propagates over the thorax delivering the vibration and compression energy. A number of studies have demonstrated that the HFCC system increases the ability to clear mucus and improves lung function. Few studies have examined the change in instantaneous heart rate (iHR) and heart rate variability (HRV) during the HFCC therapy. The purpose of this study is to measure the change of HRV with four experimental protocols: (a) without HFCC, (b) during Inflated, (c)HFCC at 6Hz, and (d) HFCC at 21Hz. The nonlinearity and regularity of HRV was assessed by approximate entropy (ApEn), a method used to quantify the complexities and randomness. To compute the ApEn, we sectioned with a total of eight epochs and displayed the ApEn over the each epoch. Our results show significant differences in the both the iHR and HRV between the experimental protocols. The iHR was elevated at both the (c) 6Hz and (d) 21Hz condition from without HFCC (10%, 16%, respectively). We also found that the HFCC system tends to increase the HRV. Our study suggests that monitoring iHR and HRV are very important physiological indexes during HFCC therapy. PMID:18002145

Lee, Jongwon; Lee, Yong W; Warwick, Warren J

2007-01-01

279

The politics of reproduction.  

PubMed

The topic of human reproduction encompasses events throughout the human and especially female life-cycle as well as ideas and practices surrounding fertility, birth, and child care. Most of the scholarship on the subject, up through the 1960s, was based on cross-cultural surveys focused on the beliefs, norms, and values surrounding reproductive behaviors. Multiple methodologies and subspecialties, and fields like social history, human biology, and demography were utilized for the analysis. The concept of the politics of reproduction synthesizes local and global perspectives. The themes investigated include: the concept of reproduction, population control, and the internationalization of state and market interests (new reproductive technologies); social movements and contested domains; medicalization and its discontents; fertility and its control; adolescence and teen pregnancy; birth; birth attendants; the construction of infancy and the politics of child survival; rethinking the demographic transition; networks of nurturance; and meanings of menopause. The medicalization of reproduction is a central issue of studies of birth, midwifery, infertility, and reproductive technologies. Scholars have also analyzed different parts of the female life-cycle as medical problems. Other issues worth analysis include the internationalization of adoption and child care workers; the crisis of infertility of low-income and minority women who are not candidates for expensive reproductive technologies; the concerns of women at high risk for HIV whose cultural status depends on their fertility; questions of reproduction concerning, lesbians and gay men (artificial insemination and discrimination in child rearing); the study of menopause; and fatherhood. New discourse analysis is used to analyze state eugenic policies; conflicts over Western neocolonial influences in which women's status as childbearers represent nationalist interests; fundamentalist attacks on abortion rights; and the AIDS crisis. PMID:12288961

Ginsburg, F; Rapp, R

1991-01-01

280

Parallel Modem Architectures for High-Data-Rate Space Modems  

NASA Astrophysics Data System (ADS)

Existing software-defined radios (SDRs) for space are limited in data volume by several factors, including bandwidth, space-qualified analog-to-digital converter (ADC) technology, and processor throughput, e.g., the throughput of a space-qualified field-programmable gate array (FPGA). In an attempt to further improve the throughput of space-based SDRs and to fully exploit the newer and more capable space-qualified technology (ADCs, FPGAs), we are evaluating parallel transmitter/receiver architectures for space SDRs. These architectures would improve data volume for both deep-space and particularly proximity (e.g., relay) links. In this article, designs for FPGA implementation of a high-rate parallel modem are presented as well as both fixed- and floating-point simulated performance results based on a functional design that is suitable for FPGA implementation.

Satorius, E.

2014-08-01

281

A dwell position verification method for high dose rate brachytherapy.  

PubMed

Misplacement of dwell positions is a potential source of misadministration in high dose rate brachytherapy. In this work we present a dwell position verification method using fluoroscopic images. A mobile C-arm fluoroscopic machine is used to take a snapshot of the treatment machine's check cable as it reaches the most distal dwell position. This fluoroscopic image is displayed side-by-side with a treatment planning image on a dual monitor relay station at the HDR treatment console. Any discrepancy between the check cable's position on the verification image and the intended dwell position on the planning image can be identified immediately, thus avoiding the possibility of treating the wrong target volume. PMID:15753927

Liu, Lizhong; Prasad, Satish C; Bassano, Daniel A; Heavern, Joel; Keshler, Bonnie; Hahn, Seung S

2004-01-01

282

Closed cycle high-repetition-rate pulsed HF laser  

NASA Astrophysics Data System (ADS)

The design and performance of a closed cycle high repetition rate HF laser is described. A short pulse, glow discharge is formed in a 10 SF6:1 H2 gas mixture at a total pressure of approximately 110 torr within a 15 by 0.5 by 0.5 cm3 volume. Transverse, recirculated gas flow adequate to enable repetitive operation up to 3 kHz is imposed by a centrifugal fan. The fan also forces the gas through a scrubber cell to eliminate ground state HF from the gas stream. An automated gas make-up system replenishes spent gas removed by the scrubber. Typical mean laser output powers up to 3 W can be maintained for extended periods of operation.

Harris, Michael R.; Morris, A. V.; Gorton, Eric K.

1997-04-01

283

Single chain stochastic polymer modeling at high strain rates.  

SciTech Connect

Our goal is to develop constitutive relations for the behavior of a solid polymer during high-strain-rate deformations. In contrast to the classic thermodynamic techniques for deriving stress-strain response in static (equilibrium) circumstances, we employ a statistical-mechanics approach, in which we evolve a probability distribution function (PDF) for the velocity fluctuations of the repeating units of the chain. We use a Langevin description for the dynamics of a single repeating unit and a Lioville equation to describe the variations of the PDF. Moments of the PDF give the conservation equations for a single polymer chain embedded in other similar chains. To extract single-chain analytical constitutive relations these equations have been solved for representative loading paths. By this process we discover that a measure of nonuniform chain link displacement serves this purpose very well. We then derive an evolution equation for the descriptor function, with the result being a history-dependent constitutive relation.

Harstad, E. N. (Eric N.); Harlow, Francis Harvey,; Schreyer, H. L.

2001-01-01

284

Effect of high dose rate irradiations on COTS optical fibres  

NASA Astrophysics Data System (ADS)

Commercial off-the-shelf (COTS) single-mode and multimode germanosilicate optical fibres are intended for use as part of control-command applications in the future Laser Megajoule facility. We evaluated their vulnerability to the radiative environment associated to this project by characterizing their transient radiation responses at infrared wavelengths (1064, 1310 and 1550 nm) after high dose rate exposure (> 108 Gy/s). Our results showed that these COTS fibres exhibit very different transient responses (10-9 s to 1 s after pulse) and permanent damages (times > 1s), depending on the wavelength of transmitted signal and on their compositions. Presented results could be used to define several choices to ensure the functionality of these applications for both shortest times after a shot (10-9 to 103 s) and during the whole LMJ lifetime (30 years).

Girard, Sylvain; Baggio, Jacques; Martinez, Martial

2005-05-01

285

Performance of drift-tube detectors at high counting rates for high-luminosity LHC upgrades  

NASA Astrophysics Data System (ADS)

The performance of pressurized drift-tube detectors at very high background rates has been studied at the Gamma Irradiation Facility (GIF) at CERN and in an intense 20 MeV proton beam at the Munich Van-der-Graaf tandem accelerator for applications in large-area precision muon tracking at high-luminosity upgrades of the Large Hadron Collider (LHC). The ATLAS muon drift-tube (MDT) chambers with 30 mm tube diameter have been designed to cope with ? and neutron background hit rates of up to 500 Hz/cm2. Background rates of up to 14 kHz/cm2 are expected at LHC upgrades. The test results with standard MDT readout electronics show that the reduction of the drift-tube diameter to 15 mm, while leaving the operating parameters unchanged, vastly increases the rate capability well beyond the requirements. The development of new small-diameter muon drift-tube (sMDT) chambers for LHC upgrades is completed. Further improvements of tracking efficiency and spatial resolution at high counting rates will be achieved with upgraded readout electronics employing improved signal shaping for high counting rates.

Bittner, Bernhard; Dubbert, Jörg; Kortner, Oliver; Kroha, Hubert; Manfredini, Alessandro; Nowak, Sebastian; Ott, Sebastian; Richter, Robert; Schwegler, Philipp; Zanzi, Daniele; Biebel, Otmar; Hertenberger, Ralf; Ruschke, Alexander; Zibell, Andre

2013-12-01

286

Why Are U.S. Incarceration Rates So High?  

Microsoft Academic Search

Most explanations of the unprecedented increase in American incarceration rates are inadequate. Crime rate increases, more punitive public attitudes, postmodernist angst, and cynical politics are all only part of the explanation. Those things characterize all Western countries; in some of these countries, imprisonment rates have long been stable or declining, and, where they are rising, absolute levels and rates of

Michael Tonry

1999-01-01

287

Do highly ornamented and less parasitized males have high quality sperm? – an experimental test for parasite-induced reproductive trade-offs in European minnow (Phoxinus phoxinus)  

PubMed Central

Parasites take their resources from hosts and thus directly reduce available resources for hosts’ own body functions, such as growth and reproduction. Furthermore, parasite infections cause significant indirect costs to their hosts in terms of increased investments on immune defense. In this study, we investigated the impact of parasite infection on the sperm quality and expression of secondary sexual ornamentation (saturation of the red abdominal colouration and number of breeding tubercles) in the Eurasian minnow (Phoxinus phoxinus). We exposed minnows to a high and low dose of common nonspecific fish ectoparasite, the glochidia larvae of duck mussel (Anodonta anatina) and tested whether parasite infection leads to trade-off in sperm quality and/or ornamental expression. We found that glochidia infection reduces the curvature of the sperm swimming trajectory, number of breeding tubercles, and possibly male competitive ability, but does not affect expression of male color ornamentation. Furthermore, glochidia infection was found to reduce sperm motility, but only when all the noninfected individuals were excluded from the model. Supporting one of the predictions by phenotype-linked fertility hypothesis both in high-infection and low-infection group male breeding colouration was positively associated with sperm quality. Our results suggest that although glochidia infection may have negative impact on male reproductive success, parasite-induced costs may not create strong trade-off between breeding colouration and sperm quality or that such trade-off become detectable only in resource-limited conditions. PMID:25540686

Kekäläinen, Jukka; Pirhonen, Juhani; Taskinen, Jouni

2014-01-01

288

Do highly ornamented and less parasitized males have high quality sperm? - an experimental test for parasite-induced reproductive trade-offs in European minnow (Phoxinus phoxinus).  

PubMed

Parasites take their resources from hosts and thus directly reduce available resources for hosts' own body functions, such as growth and reproduction. Furthermore, parasite infections cause significant indirect costs to their hosts in terms of increased investments on immune defense. In this study, we investigated the impact of parasite infection on the sperm quality and expression of secondary sexual ornamentation (saturation of the red abdominal colouration and number of breeding tubercles) in the Eurasian minnow (Phoxinus phoxinus). We exposed minnows to a high and low dose of common nonspecific fish ectoparasite, the glochidia larvae of duck mussel (Anodonta anatina) and tested whether parasite infection leads to trade-off in sperm quality and/or ornamental expression. We found that glochidia infection reduces the curvature of the sperm swimming trajectory, number of breeding tubercles, and possibly male competitive ability, but does not affect expression of male color ornamentation. Furthermore, glochidia infection was found to reduce sperm motility, but only when all the noninfected individuals were excluded from the model. Supporting one of the predictions by phenotype-linked fertility hypothesis both in high-infection and low-infection group male breeding colouration was positively associated with sperm quality. Our results suggest that although glochidia infection may have negative impact on male reproductive success, parasite-induced costs may not create strong trade-off between breeding colouration and sperm quality or that such trade-off become detectable only in resource-limited conditions. PMID:25540686

Kekäläinen, Jukka; Pirhonen, Juhani; Taskinen, Jouni

2014-11-01

289

Analysis of the swine tracheobronchial lymphnode transcriptomic response to infection with a Chinese highly pathogenic strain of porcine reproductive and respiratory syndrome virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen of swine worldwide. Emergence in 2006 of a novel highly pathogenic PRRSV (HP-PRRSV) isolate in China necessitated a comparative investigation into the host transcriptome response in tracheobronchial lymph nodes (TBLN) 14...

290

Environmental constraints on the growth, photosynthesis and reproductive development of Dryas octopetala at a high Arctic polar semi-desert, Svalbard  

Microsoft Academic Search

Opportunities exist in high Arctic polar semidesert communities for colonisation of unvegetated ground by long-lived clonal plants such as Dryas octopetala. This can be achieved by lateral spread of vegetative ramets, or by sexual reproduction and seedling recruitment. The objectives of this study were (1) to determine whether these two means of proliferation show differential sensitivity to contrasting components of

P. A. Wookey; C. H. Robinson; A. N. Parsons; J. M. Welker; T. V. Callaghan; J. A. Lee

1995-01-01

291

NEONATAL LOW- AND HIGH-DOSE EXPOSURE TO ESTRADIOL BENZOATE IN THE MALE RAT: II. EFFECTS ON THE MALE PUBERTY AND THE REPRODUCTIVE TRACT  

EPA Science Inventory

NEONATAL LOW- AND HIGH-DOSE EXPOSURE TO ESTRADIOL BENZOATE IN THE MALE RAT: II. EFFECTS ON MALE PUBERTY AND THE REPRODUCTIVE TRACT. Oliver Putz, Christian B. Schwartz, Gerald A. LeBlanc, Ralph L. Cooper, Gail S. Prins ABSTRACT Environmental contaminants with estrogen...

292

Secondary infection with Streptococcus suis serotype 7 increases the virulence of highly pathogenic porcine reproductive and respiratory syndrome virus in pigs  

Microsoft Academic Search

BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) and Streptococcus suis are common pathogens in pigs. In samples collected during the porcine high fever syndrome (PHFS) outbreak in many parts of China, PRRSV and S. suis serotype 7 (SS7) have always been isolated together. To determine whether PRRSV-SS7 coinfection was the cause of the PHFS outbreak, we evaluated the pathogenicity

Min Xu; Shujie Wang; Linxi Li; Liancheng Lei; Yonggang Liu; Wenda Shi; Jiabin Wu; Liqin Li; Fulong Rong; Mingming Xu; Guangli Sun; Hua Xiang; Xuehui Cai

2010-01-01

293

Metrology challenges for high-rate nanomanufacturing of polymer structures  

NASA Astrophysics Data System (ADS)

The transfer of nanoscience accomplishments into commercial products is hindered by the lack of understanding of barriers to nanoscale manufacturing. We have developed a number of nanomanufacturing processes that leverage available high-rate plastics fabrication technologies. These processes include directed assembly of a variety of nanoelements, such as nanoparticles and nanotubes, which are then transferred onto a polymer substrate for the fabrication of conformal/flexible electronic materials, among other applications. These assembly processes utilize both electric fields and/or chemical functionalization. Conducting polymers and carbon nanotubes have been successfully transferred to a polymer substrate in times less than 5 minutes, which is commercially relevant and can be utilized in a continuous (reel to reel/roll to roll) process. Other processes include continuous high volume mixing of nanoelements (CNTs, etc) into polymers, multi-layer extrusion and 3D injection molding of polymer structures. These nanomanufacturing processes can be used for wide range of applications, including EMI shielding, flexible electronics, structural materials, and novel sensors (specifically for chem/bio detection). Current techniques to characterize the quality and efficacy of the processes are quite slow. Moreover, the instrumentation and metrology needs for these manufacturing processes are varied and challenging. Novel, rapid, in-line metrology to enable the commercialization of these processes is critically needed. This talk will explore the necessary measurement needs for polymer based nanomanufacturing processes for both step and continuous (reel to reel/roll to roll) processes.

Mead, Joey; Barry, Carol; Busnaina, Ahmed; Isaacs, Jacqueline

2012-10-01

294

The Energetic Metal Composite under High Strain Rate  

NASA Astrophysics Data System (ADS)

Composites with energetic materials like Titanium (Ti), Nickel (Ni), etc. could react upon high velocity impact to absorb some part of the kinetic energy. The impact induced transformation of the composite was characterized by a high-speed digital camera. Ti based composites were pressed and sintered into small rod which was attached to the front of copper rod for test. A series of Taylor impact tests have been carried out on in Ti composite at a velocity range from 118m/s to 308 m/s, and the visible light caused by the composite transformation was observed in all of the cases. The ignition time decreased with increasing impact velocity, but at a decreasing rate. During the impact process, Ti composites first deformed under the impact force, then the copper rod began punching into the sample until the diameter of the sample exceeded the diameter of the copper rod. Light was detected indicating transformation in the composite, at which point the axial strain was in the range of 50% - 60%, and the areal strain was in range of 140% - 170%. Smaller samples were also prepared for the Taylor impact test, and similar phenomenon was observed irrespective of the sample size. It is believed that the shear component of the impact stress played an important role in triggering the transformation of Ti composites. Several Taylor impact tests were also performed to characterize various Ti composite and the results will be presented in this talk.

Shen, Yubin; Thadhani, Naresh; Cook, Fred; Jacob, Karl I.

2009-06-01

295

An integrated CMOS high data rate transceiver for video applications  

NASA Astrophysics Data System (ADS)

This paper presents a 5 GHz CMOS radio frequency (RF) transceiver built with 0.18 ?m RF-CMOS technology by using a proprietary protocol, which combines the new IEEE 802.11n features such as multiple-in multiple-out (MIMO) technology with other wireless technologies to provide high data rate robust real-time high definition television (HDTV) distribution within a home environment. The RF frequencies cover from 4.9 to 5.9 GHz: the industrial, scientific and medical (ISM) band. Each RF channel bandwidth is 20 MHz. The transceiver utilizes a direct up transmitter and low-IF receiver architecture. A dual-quadrature direct up conversion mixer is used that achieves better than 35 dB image rejection without any on chip calibration. The measurement shows a 6 dB typical receiver noise figure and a better than 33 dB transmitter error vector magnitude (EVM) at -3 dBm output power.

Yaping, Liang; Dazhi, Che; Cheng, Liang; Lingling, Sun

2012-07-01

296

Applying nutrition and physiology to improve reproduction in dairy cattle.  

PubMed

The establishment and maintenance of pregnancy in lactating dairy cows is a complex biological event that is influenced by a multitude of factors, from the reproductive biology of the cow to managerial aspects of the dairy farm. It is often mentioned in the scientific literature that fertility in dairy cows has declined concurrent with major advances in milk production. Some of this decline is attributed to the negative genetic correlation between milk production and reproduction. In the United States, yearly production per cow has increased steadily at a rate of 1.3% in the last decade and it is likely that this trend will continue in the years to come. At this rate, the average cow in the United States will be producing over 14 tons of milk per year in 2050 and technologies will have to be developed to allow these cows to reproduce to maintain the sustainability of dairy production. Despite high production, it is not uncommon for dairy herds with rolling herd averages for milk yield above 11,000 kg to overcome the challenges of reproduction and obtain satisfactory reproductive performance. Among other things, those herds have been able to mitigate some of the mechanisms that suppress reproduction in dairy cows such as extended postpartum anovulatory period, poor estrous detection, low pregnancy per insemination and, to a lesser extent, the high pregnancy loss. The success of those farms comes from an integrated approach to fertility that includes adequate cow comfort, elaborated transition cow management and nutrition, aggressive postpartum health monitoring program with preventative and curative measures to mitigate the negative effects of diseases on reproduction, and a sound reproductive program that includes manipulation of the ovarian cycle to allow for increased insemination rate. More recently, introduction of fertility traits in selection programs have created new opportunities for improved reproduction without neglecting economically important production traits. PMID:21755686

Santos, J E P; Bisinotto, R S; Ribeiro, E S; Lima, F S; Greco, L F; Staples, C R; Thatcher, W W

2010-01-01

297

Epidemiologic study of Holstein dairy cow performance and reproduction near a high-voltage direct-current powerline.  

PubMed

The development and operation of a high-voltage direct-current (HVDC) transmission line in rural Minnesota generated public concern over potential adverse effects to nearby residents and their livestock. Electrical environmental parameters near an HVDC line decline rapidly with distance, but effects on ambient space charge have been detected out to 1 mile. Previous studies of powerline effects on livestock have involved the more common alternating-current (HVAC) lines, which create a different electrical environment. To identify potential adverse effects of HVDC line operation on livestock, case-control and cohort study methods were used to examine various indices of Holstein performance in relation to distance from the line and the onset of line operation. It was believed that these indices would reflect changes in physiologic function or overt health effects that might arise from the HVDC environment. High-quality performance data from existing Dairy Herd Improvement Association (DHIA) records were obtained for 97% of qualifying herds located within 10 miles of the line. The large number of animals and years of observation provided high statistical power to detect even small systematic changes in performance. No significant differences in milk production or reproductive capacity were associated with presumed exposure to the HVDC environment. The absence of measurable effects in a large "sentinel" animal population may have implications for the assessment of human health risks related to HVDC transmission lines. PMID:3772982

Martin, F B; Bender, A; Steuernagel, G; Robinson, R A; Revsbech, R; Sorensen, D K; Williamson, N; Williams, A

1986-01-01

298

Genomic Sequencing Reveals Mutations Potentially Related to the Overattenuation of a Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus  

PubMed Central

Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) continues to evolve when serially passaged in Marc-145 cells. In this study, we analyzed the genomic and antigenic variants of HP-PRRSV strain JXA1 during in vitro passage. Protective efficacies of JXA1 from passages 100, 110, 120, 140, and 170 against the high-virulence parental virus were evaluated by inoculating pigs with each of these viruses and then challenging with JXA1 from passage 5 at 28 days postimmunization. We found that the antigenicities of JXA1 from passages after 110 were significantly reduced. Inoculation with JXA1 from passages after 110 provided only insufficient protection against the parental strain challenge, indicating that the immunogenicity of JXA1 is significantly decreased when it is in vitro passaged for 110 times and more. To identify the genomic variants that emerged during the overattenuation, eight complete genomes of highly passaged JXA1 were sequenced. One guanine deletion in the 5? untranslated region (UTR), two nucleotide substitutions in the 3? UTR, and 65 amino acid mutations in nonstructural and structural proteins that accompanied with the attenuation and overattenuation were determined. Genomic sequencing of in vitro serially passaged HP-PRRSV first identified the mutations potentially correlated with the overattenuation of a HP-PRRSV strain. These results facilitate the research aimed at elucidating the mechanisms for PRRSV genomic and antigenic changes and may also contribute to developing a safe and effective PRRSV vaccine. PMID:23408525

Yu, Xiuling; Chen, Nanhua; Deng, Xiaoyu; Cao, Zhen; Han, Wei; Hu, Dongmei; Wu, Jiajun; Zhang, Shuo; Wang, Baoyue; Gu, Xiaoxue

2013-01-01

299

Cryogenic, high-resolution x-ray detector with high count rate capability  

DOEpatents

A cryogenic, high-resolution X-ray detector with high count rate capability has been invented. The new X-ray detector is based on superconducting tunnel junctions (STJs), and operates without thermal stabilization at or below 500 mK. The X-ray detector exhibits good resolution (.about.5-20 eV FWHM) for soft X-rays in the keV region, and is capable of counting at count rates of more than 20,000 counts per second (cps). Simple, FET-based charge amplifiers, current amplifiers, or conventional spectroscopy shaping amplifiers can provide the electronic readout of this X-ray detector.

Frank, Matthias (Oakland, CA); Mears, Carl A. (Windsor, CA); Labov, Simon E. (Berkeley, CA); Hiller, Larry J. (Livermore, CA); Barfknecht, Andrew T. (Menlo Park, CA)

2003-03-04

300

THE DISCOUNTED REPRODUCTIVE NUMBER FOR EPIDEMIOLOGY  

PubMed Central

The basic reproductive number, , and the effective reproductive number, , are commonly used in mathematical epidemiology as summary statistics for the size and controllability of epidemics. However, these commonly used reproductive numbers can be misleading when applied to predict pathogen evolution because they do not incorporate the impact of the timing of events in the life-history cycle of the pathogen. To study evolution problems where the host population size is changing, measures like the ultimate proliferation rate must be used. A third measure of reproductive success, which combines properties of both the basic reproductive number and the ultimate proliferation rate, is the discounted reproductive number . The discounted reproductive number is a measure of reproductive success that is an individual’s expected lifetime offspring production discounted by the background population growth rate. Here, we draw attention to the discounted reproductive number by providing an explicit definition and a systematic application framework. We describe how the discounted reproductive number overcomes the limitations of both the standard reproductive numbers and proliferation rates, and show that is closely connected to Fisher’s reproductive values for different life-history stages PMID:19364158

Reluga, Timothy C.; Medlock, Jan; Galvani, Alison

2013-01-01

301

Anti-D Antibodies Among Women ....... African Journal of Reproductive Health Vol 13 No 3 September 2009  

E-print Network

Anti-D Antibodies Among Women ....... African Journal of Reproductive Health Vol 13 No 3 September 2009 47 ORIGINAL RESEARCH ARTICLE High Prevalence of Anti-D Antibodies Among Women of Childbearing Age to determine anti-D and D-negative phenotype rates among Cameroonian women of reproductive age (15 ­ 44 years

Paris-Sud XI, Université de

302

REPRODUCTION WITHIN MARMOTINE GROUND SQUIRRELS (SCIURIDAE, XERINAE, MARMOTINI): PATTERNS  

E-print Network

REPRODUCTION WITHIN MARMOTINE GROUND SQUIRRELS (SCIURIDAE, XERINAE, MARMOTINI): PATTERNS AMONG The sciurid tribe Marmotini has a distinctive, highly specialized reproductive profile characterized genera of marmotines follow the reproductive profile of the tribe. In fact, included in the tribe

Hayssen, Virginia

303

A model for estimating the minimum number of offspring to sample in studies of reproductive success.  

PubMed

Molecular parentage permits studies of selection and evolution in fecund species with cryptic mating systems, such as fish, amphibians, and insects. However, there exists no method for estimating the number of offspring that must be assigned parentage to achieve robust estimates of reproductive success when only a fraction of offspring can be sampled. We constructed a 2-stage model that first estimated the mean (?) and variance (v) in reproductive success from published studies on salmonid fishes and then sampled offspring from reproductive success distributions simulated from the ? and v estimates. Results provided strong support for modeling salmonid reproductive success via the negative binomial distribution and suggested that few offspring samples are needed to reject the null hypothesis of uniform offspring production. However, the sampled reproductive success distributions deviated significantly (?(2) goodness-of-fit test p value < 0.05) from the known simulated reproductive success distribution at rates often >0.05 and as high as 0.24, even when hundreds of offspring were assigned parentage. In general, reproductive success patterns were less accurate when offspring were sampled from cohorts with larger numbers of parents and greater variance in reproductive success. Our model can be reparameterized with data from other species and will aid researchers in planning reproductive success studies by providing explicit sampling targets required to accurately assess reproductive success. PMID:21697079

Anderson, Joseph H; Ward, Eric J; Carlson, Stephanie M

2011-01-01

304

Rate of Change Knowledge in High School and College Students.  

ERIC Educational Resources Information Center

Rate of change has its basis in everyday experience like growth and motion and is a fundamental organizing idea for relationships between varying quantities. In this paper three types of rate of change knowledge for functions are discussed: global, interval, and point-wise. Each of these types of rate of change knowledge can be examined using…

Hauger, Garnet Smith

305

An infrared high rate video imager for various space applications  

NASA Astrophysics Data System (ADS)

Modern spacecraft with high data transmission capabilities have opened up the possibility to fly video rate imagers in space. Several fields concerned with observations of transient phenomena can benefit significantly from imaging at video frame rate. Some applications are observations and characterization of bolides/meteors, sprites, lightning, volcanic eruptions, and impacts on airless bodies. Applications can be found both on low and high Earth orbiting spacecraft as well as on planetary and lunar orbiters. The optimum wavelength range varies depending on the application but we will focus here on the near infrared, partly since it allows exploration of a new field and partly because it, in many cases, allows operation both during day and night. Such an instrument has to our knowledge never flown in space so far. The only sensors of a similar kind fly on US defense satellites for monitoring launches of ballistic missiles. The data from these sensors, however, is largely inaccessible to scientists. We have developed a bread-board version of such an instrument, the SPOSH-IR. The instrument is based on an earlier technology development - SPOSH - a Smart Panoramic Optical Sensor Head, for operation in the visible range, but with the sensor replace by a cooled IR detector and new optics. The instrument is using a Sofradir 320x256 pixel HgCdTe detector array with 30µm pixel size, mounted directly on top of a four stage thermoelectric Peltier cooler. The detector-cooler combination is integrated into an evacuated closed package with a glass window on its front side. The detector has a sensitive range between 0.8 and 2.5 µm. The optical part is a seven lens design with a focal length of 6 mm and a FOV 90deg by 72 deg optimized for use at SWIR. The detector operates at 200K while the optics operates at ambient temperature. The optics and electronics for the bread-board has been designed and built by Jena-Optronik, Jena, Germany. This talk will present the design and the strong and the weak points as found through testing will be identified. Possible alternatives for improvements will be discussed and two flight applications will be outlined.

Svedhem, Hâkan; Koschny, Detlef

2010-05-01

306

High-order harmonic generation using a high-repetition-rate turnkey laser.  

PubMed

We generate high-order harmonics at high pulse repetition rates using a turnkey laser. High-order harmonics at 400 kHz are observed when argon is used as target gas. In neon, we achieve generation of photons with energies exceeding 90 eV (?13 nm) at 20 kHz. We measure a photon flux of up to 4.4 × 10(10) photons per second per harmonic in argon at 100 kHz. Many experiments employing high-order harmonics would benefit from higher repetition rates, and the user-friendly operation opens up for applications of coherent extreme ultra-violet pulses in new research areas. PMID:25554271

Lorek, E; Larsen, E W; Heyl, C M; Carlström, S; Pale?ek, D; Zigmantas, D; Mauritsson, J

2014-12-01

307

High-k (k=30) amorphous hafnium oxide films from high rate room temperature deposition  

SciTech Connect

Amorphous hafnium oxide (HfO{sub x}) is deposited by sputtering while achieving a very high k{approx}30. Structural characterization suggests that the high k is a consequence of a previously unreported cubiclike short range order in the amorphous HfO{sub x} (cubic k{approx}30). The films also possess a high electrical resistivity of 10{sup 14} {Omega} cm, a breakdown strength of 3 MV cm{sup -1}, and an optical gap of 6.0 eV. Deposition at room temperature and a high deposition rate ({approx}25 nm min{sup -1}) makes these high-k amorphous HfO{sub x} films highly advantageous for plastic electronics and high throughput manufacturing.

Li, Flora M.; Bayer, Bernhard C.; Hofmann, Stephan; Milne, William I.; Flewitt, Andrew J. [Department of Engineering, Electrical Engineering Division, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Dutson, James D.; Wakeham, Steve J.; Thwaites, Mike J. [Plasma Quest Ltd., Unit 1B, Rose Estate, Osborn Way, Hook, Hampshire RG27 9UT (United Kingdom)

2011-06-20

308

Coherent Detection of High-Rate Optical PPM Signals  

NASA Technical Reports Server (NTRS)

A method of coherent detection of high-rate pulse-position modulation (PPM) on a received laser beam has been conceived as a means of reducing the deleterious effects of noise and atmospheric turbulence in free-space optical communication using focal-plane detector array technologies. In comparison with a receiver based on direct detection of the intensity modulation of a PPM signal, a receiver based on the present method of coherent detection performs well at much higher background levels. In principle, the coherent-detection receiver can exhibit quantum-limited performance despite atmospheric turbulence. The key components of such a receiver include standard receiver optics, a laser that serves as a local oscillator, a focal-plane array of photodetectors, and a signal-processing and data-acquisition assembly needed to sample the focal-plane fields and reconstruct the pulsed signal prior to detection. The received PPM-modulated laser beam and the local-oscillator beam are focused onto the photodetector array, where they are mixed in the detection process. The two lasers are of the same or nearly the same frequency. If the two lasers are of different frequencies, then the coherent detection process is characterized as heterodyne and, using traditional heterodyne-detection terminology, the difference between the two laser frequencies is denoted the intermediate frequency (IF). If the two laser beams are of the same frequency and remain aligned in phase, then the coherent detection process is characterized as homodyne (essentially, heterodyne detection at zero IF). As a result of the inherent squaring operation of each photodetector, the output current includes an IF component that contains the signal modulation. The amplitude of the IF component is proportional to the product of the local-oscillator signal amplitude and the PPM signal amplitude. Hence, by using a sufficiently strong local-oscillator signal, one can make the PPM-modulated IF signal strong enough to overcome thermal noise in the receiver circuits: this is what makes it possible to achieve near-quantum-limited detection in the presence of strong background. Following quantum-limited coherent detection, the outputs of the individual photodetectors are automatically aligned in phase by use of one or more adaptive array compensation algorithms [e.g., the least-mean-square (LMS) algorithm]. Then the outputs are combined and the resulting signal is processed to extract the high-rate information, as though the PPM signal were received by a single photodetector. In a continuing series of experiments to test this method (see Fig. 1), the local oscillator has a wavelength of 1,064 nm, and another laser is used as a signal transmitter at a slightly different wavelength to establish an IF of about 6 MHz. There are 16 photodetectors in a 4 4 focal-plane array; the detector outputs are digitized at a sampling rate of 25 MHz, and the signals in digital form are combined by use of the LMS algorithm. Convergence of the adaptive combining algorithm in the presence of simulated atmospheric turbulence for optical PPM signals has already been demonstrated in the laboratory; the combined output is shown in Fig. 2(a), and Fig. 2(b) shows the behavior of the phase of the combining weights as a function of time (or samples). We observe that the phase of the weights has a sawtooth shape due to the continuously changing phase in the down-converted output, which is not exactly at zero frequency. Detailed performance analysis of this coherent free-space optical communication system in the presence of simulated atmospheric turbulence is currently under way.

Vilnrotter, Victor; Fernandez, Michela Munoz

2006-01-01

309

Process for High-Rate Fabrication of Alumina Nanotemplates  

NASA Technical Reports Server (NTRS)

An anodizing process, at an early stage of development at the time of reporting the information for this article, has shown promise as a means of fabricating alumina nanotemplates integrated with silicon wafers. Alumina nanotemplates are basically layers of alumina, typically several microns thick, in which are formed approximately regular hexagonal arrays of holes having typical diameters of the order of 10 to 100 nm. Interest in alumina nanotemplates has grown in recent years because they have been found to be useful as templates in the fabrication of nanoscale magnetic, electronic, optoelectronic, and other devices. The present anodizing process is attractive for the fabrication of alumina nanotemplates integrated with silicon wafers in two respects: (1) the process involves self-ordering of the holes; that is, the holes as formed by the process are spontaneously arranged in approximately regular hexagonal arrays; and (2) the rates of growth (that is, elongation) of the holes are high enough to make the process compatible with other processes used in the mass production of integrated circuits. In preparation for fabrication of alumina nanotemplates in this process, one first uses electron-beam evaporation to deposit thin films of titanium, followed by thin films of aluminum, on silicon wafers. Then the alumina nanotemplates are formed by anodizing the aluminum layers, as described below. In experiments in which the process was partially developed, the titanium films were 200 A thick and the aluminum films were 5 m thick. The aluminum films were oxidized to alumina, and the arrays of holes were formed by anodizing the aluminum in aqueous solutions of sulfuric and/or oxalic acid at room temperature (see figure). The diameters, spacings, and rates of growth of the holes were found to depend, variously, on the composition of the anodizing solution, the applied current, or the applied potential, as follows: In galvanostatically controlled anodizing, regardless of the chemical composition of the solution, relatively high current densities (50 to 100 mA/cm2) resulted in arrays of holes that were more nearly regular than were those formed at lower current densities. . The rates of elongation of the holes were found to depend linearly on the applied current density: the observed factor of proportionality was 1.2 (m/h)/(mA/cm2). For a given fixed current density and room temperature, the hole diameters were found to depend mainly on the chemical compositions of the anodizing solutions. The holes produced in sulfuric acid solutions were smaller than those produced in oxalic acid solutions. The arrays of holes produced in sulfuric acid were more ordered than were those produced in oxalic acid. . The breakdown voltage was found to decrease logarithmically with increasing concentration of sulfuric acid. The breakdown voltage was also found to decrease with temperature and to be accompanied by a decrease in hole diameter. The hole diameter was found to vary linearly with applied potential, with a slope of 2.1 nm/V. This slope differs from slopes (2.2 and 2.77 nm/V) reported for similar prior measurements on nanotemplates made from bulk aluminum. The differences among these slopes may be attributable to differences among impurities and defects in bulk and electron-beam-evaporated aluminum specimens.

Myung, Nosang; Fleurial, Jean-Pierre; Yun, Minhee; West, William; Choi, Daniel

2007-01-01

310

Steady State Microbunching for High Brilliance and High Repetition Rate Storage Ring-Based Light Sources  

SciTech Connect

Electron-based light sources have proven to be effective sources of high brilliance, high frequency radiation. Such sources are typically either linac-Free Electron Laser (FEL) or storage ring types. The linac-FEL type has high brilliance (because the beam is microbunched) but low repetition rate. The storage ring type has high repetition rate (rapid beam circulation) but comparatively low brilliance or coherence. We propose to explore the feasibility of a microbunched beam in a storage ring that promises high repetition rate and high brilliance. The steady-state-micro-bunch (SSMB) beam in storage ring could provide CW sources for THz, EUV, or soft X-rays. Several SSMB mechanisms have been suggested recently, and in this report, we review a number of these SSMB concepts as promising directions for high brilliance, high repetition rate light sources of the future. The trick of SSMB lies in the RF system, together with the associated synchrotron beam dynamics, of the storage ring. Considering various different RF arrangements, there could be considered a number of scenarios of the SSMB. In this report, we arrange these scenarios more or less in order of the envisioned degree of technical challenge to the RF system, and not in the chronological order of their original references. Once the stored beam is steady-state microbunched in a storage ring, it passes through a radiator repeatedly every turn (or few turns). The radiator extracts a small fraction of the beam energy as coherent radiation with a wavelength corresponding to the microbunched period of the beam. In contrast to an FEL, this radiator is not needed to generate the microbunching (as required e.g. by SASE FELs or seeded FELs), so the radiator can be comparatively simple and short.

Chao, Alex; Ratner, Daniel; /SLAC; Jiao, Yi; /Beijing, Inst. High Energy Phys.

2012-09-06

311

Strain rate viscoelastic analysis of soft and highly hydrated biomaterials.  

PubMed

Measuring the viscoelastic behavior of highly hydrated biological materials is challenging because of their intrinsic softness and labile nature. In these materials, it is difficult to avoid prestress and therefore to establish precise initial stress and strain conditions for lumped parameter estimation using creep or stress-relaxation (SR) tests. We describe a method ( ??M or epsilon dot method) for deriving the viscoelastic parameters of soft hydrated biomaterials which avoids prestress and can be used to rapidly test degradable samples. Standard mechanical tests are first performed compressing samples using different strain rates. The dataset obtained is then analyzed to mathematically derive the material's viscoelastic parameters. In this work a stable elastomer, polydimethylsiloxane, and a labile hydrogel, gelatin, were first tested using the ??M, in parallel SR was used to compare lumped parameter estimation. After demonstrating that the elastic parameters are equivalent and that the estimation of short-time constants is more precise using the proposed method, the viscoelastic behavior of porcine liver was investigated using this approach. The results show that the constitutive parameters of hepatic tissue can be quickly quantified without the application of any prestress and before the onset of time-dependent degradation phenomena. PMID:23946054

Tirella, A; Mattei, G; Ahluwalia, A

2014-10-01

312

Smart Payload Development for High Data Rate Instrument Systems  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the development of smart payloads instruments systems with high data rates. On-board computation has become a bottleneck for advanced science instrument and engineering capabilities. In order to improve the computation capability on board, smart payloads have been proposed. A smart payload is a Localized instrument, that can offload the flight processor of extensive computing cycles, simplify the interfaces, and minimize the dependency of the instrument on the flight system. This has been proposed for the Mars mission, Mars Atmospheric Trace Molecule Spectroscopy (MATMOS). The design of this system is discussed; the features of the Virtex-4, are discussed, and the technical approach is reviewed. The proposed Hybrid Field Programmable Gate Array (FPGA) technology has been shown to deliver breakthrough performance by tightly coupling hardware and software. Smart Payload designs for instruments such as MATMOS can meet science data return requirements with more competitive use of available on-board resources and can provide algorithm acceleration in hardware leading to implementation of better (more advanced) algorithms in on-board systems for improved science data return

Pingree, Paula J.; Norton, Charles D.

2007-01-01

313

High-rate anaerobic treatment of wastewater at low temperatures.  

PubMed

Anaerobic treatment of a volatile fatty acid (VFA) mixture was investigated under psychrophilic (3 to 8 degrees C) conditions in two laboratory-scale expanded granular sludge bed reactor stages in series. The reactor system was seeded with mesophilic methanogenic granular sludge and fed with a mixture of VFAs. Good removal of fatty acids was achieved in the two-stage system. Relative high levels of propionate were present in the effluent of the first stage, but propionate was efficiently removed in the second stage, where a low hydrogen partial pressure and a low acetate concentration were advantageous for propionate oxidation. The specific VFA-degrading activities of the sludge in each of the modules doubled during system operation for 150 days, indicating a good enrichment of methanogens and proton-reducing acetogenic bacteria at such low temperatures. The specific degradation rates of butyrate, propionate, and the VFA mixture amounted to 0.139, 0.110, and 0.214 g of chemical oxygen demand g of volatile suspended solids-1 day-1, respectively. The biomass which was obtained after 1.5 years still had a temperature optimum of between 30 and 40 degrees C. PMID:10103270

Lettinga, G; Rebac, S; Parshina, S; Nozhevnikova, A; van Lier, J B; Stams, A J

1999-04-01

314

Strain rate viscoelastic analysis of soft and highly hydrated biomaterials  

PubMed Central

Measuring the viscoelastic behavior of highly hydrated biological materials is challenging because of their intrinsic softness and labile nature. In these materials, it is difficult to avoid prestress and therefore to establish precise initial stress and strain conditions for lumped parameter estimation using creep or stress-relaxation (SR) tests. We describe a method ( or epsilon dot method) for deriving the viscoelastic parameters of soft hydrated biomaterials which avoids prestress and can be used to rapidly test degradable samples. Standard mechanical tests are first performed compressing samples using different strain rates. The dataset obtained is then analyzed to mathematically derive the material's viscoelastic parameters. In this work a stable elastomer, polydimethylsiloxane, and a labile hydrogel, gelatin, were first tested using the, in parallel SR was used to compare lumped parameter estimation. After demonstrating that the elastic parameters are equivalent and that the estimation of short-time constants is more precise using the proposed method, the viscoelastic behavior of porcine liver was investigated using this approach. The results show that the constitutive parameters of hepatic tissue can be quickly quantified without the application of any prestress and before the onset of time-dependent degradation phenomena. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3352–3360, 2014 PMID:23946054

Tirella, A; Mattei, G; Ahluwalia, A

2014-01-01

315

Algal biofuels from wastewater treatment high rate algal ponds.  

PubMed

This paper examines the potential of algae biofuel production in conjunction with wastewater treatment. Current technology for algal wastewater treatment uses facultative ponds, however, these ponds have low productivity (?10 tonnes/ha.y), are not amenable to cultivating single algal species, require chemical flocculation or other expensive processes for algal harvest, and do not provide consistent nutrient removal. Shallow, paddlewheel-mixed high rate algal ponds (HRAPs) have much higher productivities (?30 tonnes/ha.y) and promote bioflocculation settling which may provide low-cost algal harvest. Moreover, HRAP algae are carbon-limited and daytime addition of CO(2) has, under suitable climatic conditions, the potential to double production (to ?60 tonnes/ha.y), improve bioflocculation algal harvest, and enhance wastewater nutrient removal. Algae biofuels (e.g. biogas, ethanol, biodiesel and crude bio-oil), could be produced from the algae harvested from wastewater HRAPs, The wastewater treatment function would cover the capital and operation costs of algal production, with biofuel and recovered nutrient fertilizer being by-products. Greenhouse gas abatement results from both the production of the biofuels and the savings in energy consumption compared to electromechanical treatment processes. However, to achieve these benefits, further research is required, particularly the large-scale demonstration of wastewater treatment HRAP algal production and harvest. PMID:21330711

Craggs, R J; Heubeck, S; Lundquist, T J; Benemann, J R

2011-01-01

316

Asexual Reproduction in Holothurians  

PubMed Central

Aspects of asexual reproduction in holothurians are discussed. Holothurians are significant as fishery and aquaculture items and have high commercial value. The last review on holothurian asexual reproduction was published 18 years ago and included only 8 species. An analysis of the available literature shows that asexual reproduction has now been confirmed in 16 holothurian species. Five additional species are also most likely capable of fission. The recent discovery of new fissiparous holothurian species indicates that this reproduction mode is more widespread in Holothuroidea than previously believed. New data about the history of the discovery of asexual reproduction in holothurians, features of fission, and regeneration of anterior and posterior fragments are described here. Asexual reproduction is obviously controlled by the integrated systems of the organism, primarily the nervous system. Special molecular mechanisms appear to determine the location where fission occurs along the anterior-posterior axis of the body. Alteration of the connective tissue strength of the body wall may play an important role during fission of holothurians. The basic mechanism of fission is the interaction of matrix metalloproteinases, their inhibitors, and enzymes forming cross-link complexes between fibrils of collagen. The population dynamics of fissiparous holothurians are discussed. PMID:25405228

Dolmatov, Igor Yu.

2014-01-01

317

High concentration of RNA polymerase I is responsible for the high rate of nucleolar transcription.  

PubMed Central

When isolated rat liver nuclei and nucleoli are compared for RNA synthesis in vitro, the rate of nucleolar RNA synthesis is found to be more than 10 times higher. In order to understand this high rate of nucleolar transcription, DNA from both nuclear and nucleolar fractions was isolated and compared for the ability to direct RNA synthesis with homologous RNA polymerases. No difference between these two templates is evident. On the other hand, when the total nuclear and nucleolar RNA polymerases are isolated and compared on a per-unit-weight-of-DNA basis, it becomes clear that the nucleolus has a 10-fold higher RNA polymerase concentration than the nucleus. This result suggests that RNA polymerase I concentration rather than the nucleolar DNA template efficiency is responsible for the observed high rate of nucleolar transcription under the normal steady-state condition. PMID:6156675

Yu, F L

1980-01-01

318

TRP 9904 - Constitutive Behavior of High Strength Multiphase Sheel Steel Under High Strain Rate Deformation  

SciTech Connect

The focus of the research project was to systematically assess the strain rate dependence of strengthening mechanisms in new advanced high strength sheet steels. Data were obtained on specially designed and produced Duel Phase and TRIP steels and compared to the properties of automotive steels currently in use.

David Matlock; John Speer

2005-03-31

319

Research article Breeding system and reproductive skew in a highly polygynous ant population  

E-print Network

and male brood). Queen number was very high, with an arithmetic mean of 253 per nest. Most queens (90. Accord- ingly, the harmonic mean queen number (40.5) was six times lower than the arithmetic mean

Alvarez, Nadir

320

Studies on Nonaluminized High Burning Rate AP-Composite Propellants  

Microsoft Academic Search

This paper discusses the effect of replacement of hydroxyl terminated poly butadiene (HTPB) by butacene on the burning rates of a nonaluminized ammonium perchlorate (AP)–based composite propellant. A remarkable burning rate enhancement (60–100%) was observed on replacement of HTPB by butacene to the extent of 25%. Replacement of 50–75% HTPB by butacene led to further increase in burning rate by

G. M. GORE; A. N. NAZARE; C. N. DIVEKAR; S. K. HAIT; S. N. ASTHANA

2004-01-01

321

Characterization of Composites Response at High Rates of Loading  

NASA Technical Reports Server (NTRS)

The objective of the proposed research is to experimentally study the effect of strain rate on mechanical response (deformation and failure) carbon fiber/epoxy matrix composites. The experimental data provide the information needed for the development of a nonlinear, rate dependent deformation and strength models that can subsequently be used in design. This year effort was directed into testing the epoxy resin. Two types of epoxy were tested each in tension and shear at various strain rate that ranges from 5x10(exp -5), to 700/s. The results show that both the strain rate and the mode of loading affect the epoxy response.

Gilat, Amos

2002-01-01

322

High Strain-Rate Response of High Purity Aluminum at Temperatures Approaching Melt  

SciTech Connect

High-temperature, pressure-shear plate impact experiments were conducted to investigate the rate-controlling mechanisms of the plastic response of high-purity aluminum at high strain rates (10{sup 6} s{sup -1}) and at temperatures approaching melt. Since the melting temperature of aluminum is pressure dependent, and a typical pressure-shear plate impact experiment subjects the sample to large pressures (2 GPa-7 GPa), a pressure-release type experiment was used to reduce the pressure in order to measure the shearing resistance at temperatures up to 95% of the current melting temperature. The measured shearing resistance was remarkably large (50 MPa at a shear strain of 2.5) for temperatures this near melt. Numerical simulations conducted using a version of the Nemat-Nasser/Isaacs constitutive equation, modified to model the mechanism of geometric softening, appear to capture adequately the hardening/softening behavior observed experimentally.

Grunschel, S E; Clifton, R J; Jiao, T

2010-01-28

323

Design and analysis of a high-rate acoustic link for underwater video transmission  

E-print Network

A high bit rate acoustic link for underwater video transmission is examined. Currently, encoding standards support video transmission at bit rates as low as 64 kbps. While this rate is still above the limit of commercially ...

Pelekanakis, Konstantinos

2004-01-01

324

Predictive Model of Rat Reproductive Toxicity from ToxCast High Throughput Screening  

EPA Science Inventory

The EPA ToxCast research program uses high throughput screening for bioactivity profiling and predicting the toxicity of large numbers of chemicals. ToxCast Phase-I tested 309 well-characterized chemicals in over 500 assays for a wide range of molecular targets and cellular respo...

325

Part two: Early stress and later reproductive performance under conditions of malnutrition and high altitude hypoxia  

Microsoft Academic Search

The phcnotype of the adult organism is dependent upon a host of factors within its developmental framework. Stress acting upon the child during development can alter the adult phenotype in such a way that various functional processes are altered. It is the aim of this paper to explore the role that early exposure to the stresses of malnutrition and high

Ronald S. Weinstein; Jere D. Haas

1977-01-01

326

Micro Assembly By High Rate CVD Using CW UV Laser  

Microsoft Academic Search

We have developed micro assembiy technique which uses polymer as adhesive, deposited by laser assisted CVD. The laser deposition system adopted following techniques to increase deposition rate. Continuous wave (CvV) ultraviolet (UV) laser was used. The substrate was cooled to condense the source gas (vinyl acetate) on the surface. The maximum deposition rate by the laser deposition system was about

Masahisa Sugihara; K. Minarni; Masayoshi Esashi

1995-01-01

327

Characterization of Composites Response at High Rates of Deformation  

NASA Technical Reports Server (NTRS)

The objective of the proposed research is to experimentally study the effect of strain rate on mechanical response (deformation and failure) of IM-7/977-2 carbon fiber/epoxy matrix composites. The experimental data will provide the information needed for the development of a nonlinear, rate dependent deformation and strength model for this material that can subsequently be used in design.

Gilat, Amos

2001-01-01

328

High growth rate homoepitaxial diamond film deposition at high temperatures by microwave plasma-assisted chemical vapor deposition  

NASA Technical Reports Server (NTRS)

The deposition of high quality diamond films at high linear growth rates and substrate temperatures for microwave-plasma chemical vapor deposition is disclosed. The linear growth rate achieved for this process is generally greater than 50 .mu.m/hr for high quality films, as compared to rates of less than 5 .mu.m/hr generally reported for MPCVD processes.

Vohra, Yogesh K. (Inventor); McCauley, Thomas S. (Inventor)

1997-01-01

329

Synergistic effects of sequential infection with highly pathogenic porcine reproductive and respiratory syndrome virus and porcine circovirus type 2  

PubMed Central

Background Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of porcine reproductive and respiratory syndrome (PRRS) and porcine circovirus type 2 (PCV2) is associated with postweaning multisystemic wasting syndrome (PMWS) in pigs. Coinfection with highly pathogenic PRRSV (HP-PRRSV) and PCV2 in the field has recently become extensive in some Asian countries. A synergistic pathogenicity between PRRSV and PCV2 infections has previously been reported. However, the consequences of the sequential infection of pigs with these two viruses are unknown. Methods Thirty 35-day-old piglets were randomly divided into six groups (n = 5 each): HP-PRRSV/PCV2 (group 1, inoculated with HP-PRRSV, then inoculated with PCV2 one week later), PCV2/HP-PRRSV (group 2, inoculated with PCV2, then inoculated with HP-PRRSV one week later), HP-PRRSV+PCV2 (group 3, inoculated with HP-PRRSV and PCV2 concurrently), HP-PRRSV (group 4, inoculated with HP-PRRSV), PCV2 (group 5, inoculated with PCV2), and the control (group 6, uninfected). This experiment lasted 28 days. Clinical symptoms and rectal temperatures were recorded each day after inoculation, body weight was recorded weekly, and serum samples were obtained for viral nucleic acid quantification and antibody titration. Variations in CD3+, CD4+ CD8–, CD3+, CD4–, and CD8+ cells, natural killer (NK) cells, and mononuclear cells were determined by flow cytometry. The serum concentrations of interferon ? (IFN-?), tumor necrosis factor ? (TNF-?), interleukin 10 (IL-10), and macrophage granulocyte-colony stimulating factor (GM-CSF) were determined. Pathological changes in different tissues from the experimentally infected pigs were recorded. Results The piglets in group 1 had the highest viral loads, the lowest antibody titers, the most-severe clinical signs, and the highest mortality (3/5, 60%; the mortality in the other groups was 0%), and interstitial pneumonia was more severe in this group compare to the other HP-PRRSV infected groups. The serum levels of IFN-?, TNF-?, IL-10, and GM-CSF varied (increased or decreased) most widely in group 1, as did each immunocyte subgroup. Conclusions HP-PRRSV infection followed by PCV2 infection enhanced the replication of both viruses in the experimental piglets and led to more-severe clinical signs and lesions, indicating greater synergistic effects during the sequential infection of piglets with HP-PRRSV and then PCV2. PMID:23971711

2013-01-01

330

Photosynthesis in Relation to Reproductive Success of Cypripedium flavum  

PubMed Central

• Background and Aims Cypripedium flavum is a rare, endemic alpine slipper orchid of China, which is under threat from excessive collection and habitat changes. Conservation and re-introduction of C. flavum is restricted by lack of knowledge of the plant's photosynthesis and how that affects reproductive success. The hypothesis is tested that reproductive success is determined by photosynthetic production. • Methods To understand the photosynthetic characteristics and adaptation of C. flavum to alpine environments, and the relation to reproductive success, measurements were made at four field sites with varying degrees of forest cover in the Hengduan Mountains, south-west China. • Key Results Both photosynthetic capacity and reproductive traits of C. flavum are affected by light availability. Photosynthetic rate (A) is greatest around noon, following the pattern of photosynthetically active radiation (PAR) at all sites. Cypripedium flavum has highest daily mean photosynthetic rate (Adaily) and light-saturated photosynthetic rate (Amax) under a half to a third of full sunlight. High radiation decreased A. However, the optimum temperature for photosynthesis was similar (18–20 °C) at all sites. • Conclusions The quotient of daily mean photosynthetic rate to light saturated photosynthesis (Adaily/Amax) is positively correlated with the ramet number m?2 and percentage of fruiting of C. flavum. The Adaily/Amax ratio is a useful proxy for evaluating reproductive success of C. flavum. PMID:15829510

ZHANG, SHIBAO; HU, HONG; ZHOU, ZHEKUN; XU, KUN; YAN, NING; LI, SHUYUN

2005-01-01

331

Highly pathogenic porcine reproductive and respiratory syndrome virus infection results in acute lung injury of the infected pigs.  

PubMed

Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) was firstly characterized in 2006 in China. The virus has caused great economic loss to the Chinese swine production during the past years. Herein, we experimentally infected SPF pigs using two strains of PRRSV with different pathogenicity and observed the lung pathological changes looking for new sights on the possible pathogenesis associated with the virulence of HP-PRRSV. The results indicated that the HP-PRRSV-infected pigs died and exhibited severe pathological changes of lungs featuring increased neutrophils, mast cells and mononuclear macrophages, compared with the pigs inoculated with low pathogenic (LP-) PRRSV. Furthermore, the pigs infected with HP-PRRSV showed the higher levels of tumor necrosis factor (TNF)-?, interleukin (IL)-1?, interleukin (IL)-8 and histamine, leukotriene B4 (LTB4), platelet activation factor (PAF) in sera than those inoculated with LP-PRRSV. Additionally, the fibrosis of lung was observed in the HP-PRRSV-infected pigs. At present, our findings suggest that the aberrant immune responses triggered by HP-PRRSV infection are closely related to acute lung injury (ALI), and especially the pathological changes in lung vascular system are of particular significance. These associated pathological changes of lung are in part responsible for the additional morbidity and mortality observed in HP-PRRSV infection. PMID:24472226

Han, Deping; Hu, Yanxin; Li, Limin; Tian, Haiyan; Chen, Zhi; Wang, Lin; Ma, Haiyan; Yang, Hanchun; Teng, Kedao

2014-03-14

332

Thyratron characteristics under high di/dt and high-repetition-rate operation  

SciTech Connect

Power conditioning systems for high peak and average power, high repetition rate discharge excited lasers involve operation of modulator components in unconventional regimes. Reliable operation of switches and energy storage elements under high voltage and high di/dt conditions is a pacing item for laser development at the present time. To test and evaluate these components a Modulator Component Test Facility (MCTF) was constructed. The MCTF consists of a command charge system, energy storage capacitors, thyratron switch with inverse thyratron protection, and a resistive load. The modulator has initially been operated at voltages up to 60 kV at 600 Hz. Voltage, current, and calorimetric diagnostics are provided for major modulator components. Measurements of thyratron characteristics under high di/dt operation are presented. Commutation energy loss and di/dt have been measured as functions of the tube hydrogen pressure.

Ball, D.; Hill, J.; Kan, T.

1981-05-11

333

High-efficiency, all-solid-state exciters for high-repetition-rated, high-power TEA CO2 lasers  

Microsoft Academic Search

Two high-efficiency, all-solid-state exciters for pumping TEA CO2 lasers were developed, and their energy scalability, high-efficiency operation, and high repetition rate operation was experimentally proved. The small-scale all-solid-state exciter of the two-stage magnetic pulse compressor was operated with an output transfer energy of 8.8 J\\/pulse and energy transfer efficiency of 78 percent, and the average CO2 laser power of 117

Hiroshi Tanaka; Hidekazu Hatanaka; Minoru Obara; Katsumi Midorikawa; Hideo Tashiro

1990-01-01

334

Reproductive performance of broiler breeders exposed to cycling high temperatures from 17 to 20 weeks of age.  

PubMed

Forty male and 240 female broiler breeders were placed in cages within environmental chambers (20 males or 40 females per chamber) at 14 weeks of age. Chamber temperatures were maintained at 21.3 +/- 2.5 C, and relative humidity (RH) ranged from 40 to 50%. Ventilation rate was approximately 47.2 liters/sec per chamber, and light was provided from 0600 to 1800 hr. Feed was restricted daily according to industry recommendations, and water was provided ad libitum. From 17 to 20 weeks of age, control (C) chambers were kept at constant 21.0 +/- 1.4 C with 45 +/- 5% RH, and heat-treated (HT) chambers were cycled from 24.4 +/- 5.5 C (45 +/- 5% RH) during 1800 to 0800 hr to 36.0 +/- 2.8 C (15 +/- 5% RH) during 0800 to 1800 hr. Body weights were recorded at biweekly intervals. At 18 and 20 weeks of age, blood samples and rectal body temperatures were obtained randomly from five fasted birds per chamber at 0800 and 1400 hr. From 20 to 60 weeks of age, all birds were kept in individual cages in a conventional fan-ventilated house. Maximum temperature never exceeded 30 C, and average RH was 65.0%. Reproductive parameters were monitored and body weights were obtained at 4-week intervals. There were no significant treatment effects for body weight, body temperature, or differential leukocyte counts. Hematocrits were significantly lower for HT females than controls, and heat treatment did not result in consistent changes in plasma glucose or total proteins.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6483713

Renden, J A; McDaniel, G R

1984-08-01

335

Seasonal migration to high latitudes results in major reproductive benefits in an insect  

PubMed Central

Little is known of the population dynamics of long-range insect migrants, and it has been suggested that the annual journeys of billions of nonhardy insects to exploit temperate zones during summer represent a sink from which future generations seldom return (the “Pied Piper” effect). We combine data from entomological radars and ground-based light traps to show that annual migrations are highly adaptive in the noctuid moth Autographa gamma (silver Y), a major agricultural pest. We estimate that 10–240 million immigrants reach the United Kingdom each spring, but that summer breeding results in a fourfold increase in the abundance of the subsequent generation of adults, all of which emigrate southward in the fall. Trajectory simulations show that 80% of emigrants will reach regions suitable for winter breeding in the Mediterranean Basin, for which our population dynamics model predicts a winter carrying capacity only 20% of that of northern Europe during the summer. We conclude not only that poleward insect migrations in spring result in major population increases, but also that the persistence of such species is dependent on summer breeding in high-latitude regions, which requires a fundamental change in our understanding of insect migration. PMID:22927392

Chapman, Jason W.; Bell, James R.; Burgin, Laura E.; Reynolds, Donald R.; Pettersson, Lars B.; Hill, Jane K.; Bonsall, Michael B.; Thomas, Jeremy A.

2012-01-01

336

High rate properties of porcine skull bone tissue  

NASA Astrophysics Data System (ADS)

Several recent studies have shown the importance of understanding the nature of blast injuries. Traditionally, the lungs and other air filled organs were the focus of these injuries but it is being discovered that some level of brain trauma may result after encountering a blast. These injuries are referred to as traumatic brain injuries, or TBI. There has been many clinical studies and statistical analyses done concerning these injuries, but there is still no physical understanding of the problem. In order to develop a model of how this injury can occur, rate dependent material properties of the tissues the stress wave will travel through are needed. In this study, the compressive response of porcine skull bone through the thickness direction was experimentally determined over a wide range of rates, ranging from 0.001 sec -1 to approximately 3000 sec-1. The results reveal that for most mechanical properties there is a clear rate dependence of the material. However, only one subset of the skull section appeared to have a rate dependent initial modulus, with the rest showing no significant statistical dependence on loading rate. Other mechanical properties appeared to be affected by the loading rate, including the strain energy density.

Herwig, Kyle Jeffry

337

Reproductive Health  

NSDL National Science Digital Library

BioMed Central contains hundreds of important online journals in its archives, and Reproductive Health is certainly one that visitors will want to look over when they have a few moments. Reproductive Health is the official journal of the Geneva Foundation for Medical Education and Research, and was started in June 2004. It covers all aspects of human reproduction, and recent pieces have dealt with cervical cancer, maternity care, and other related topics. Visitors can view the ten most accessed articles from the journal, sign up to receive an RSS feed of the latest articles, and also email articles to friends and colleagues. For those who might be interested in submitting an article for consideration, they can also do that via this site.

338

Imploding Liner Material Strength Measurements at High-Strain and High Strain Rate  

SciTech Connect

Imploding, cylindrical liners provide a unique, shockless means of simultaneously accessing high strain and high-strain-rate for measurement of strength of materials in plastic flow. The radial convergence in the liner geometry results in the liner thickening as the circumference becomes smaller. Strains of up to {approximately}1.25 and strain rates of up to {approximately}10{sup 6} sec{sup -1} can be readily achieved in a material sample placed inside of an aluminum driver liner, using the Pegasus II capacitor bank. This provides yield strength data at conditions where none presently exists. The heating from work done against the yield strength is measured with multichannel pyrometry from infrared radiation emitted by the material sample. The temperature data as a function of liner position are unfolded to give the yield strength along the strain, strain-rate trajectory. Proper design of the liner and sample configuration ensures that the current diffused into the sample adds negligible heating. An important issue, in this type of temperature measurement, is shielding of the pickup optics from other sources of radiation. At strains greater than those achievable on Pegasus, e.g. the LANL Atlas facility, some materials may be heated all the way to melt by this process. Recent data on 6061-T6 Aluminum will be compared with an existing model for strain and strain-rate heating. The liner configuration and pyrometry diagnostic will also be discussed.

Bartsch, R.R.; Lee, H.; Holtkamp, D.; Wright, B.; Stokes, J.; Morgan, D.; Anderson, W.; Broste, W.

1998-10-18

339

Sensitive, high-strain, high-rate bodily motion sensors based on graphene-rubber composites.  

PubMed

Monitoring of human bodily motion requires wearable sensors that can detect position, velocity and acceleration. They should be cheap, lightweight, mechanically compliant and display reasonable sensitivity at high strains and strain rates. No reported material has simultaneously demonstrated all the above requirements. Here we describe a simple method to infuse liquid-exfoliated graphene into natural rubber to create conducting composites. These materials are excellent strain sensors displaying 10(4)-fold increases in resistance and working at strains exceeding 800%. The sensitivity is reasonably high, with gauge factors of up to 35 observed. More importantly, these sensors can effectively track dynamic strain, working well at vibration frequencies of at least 160 Hz. At 60 Hz, we could monitor strains of at least 6% at strain rates exceeding 6000%/s. We have used these composites as bodily motion sensors, effectively monitoring joint and muscle motion as well and breathing and pulse. PMID:25100211

Boland, Conor S; Khan, Umar; Backes, Claudia; O'Neill, Arlene; McCauley, Joe; Duane, Shane; Shanker, Ravi; Liu, Yang; Jurewicz, Izabela; Dalton, Alan B; Coleman, Jonathan N

2014-09-23

340

Versatile high rate plasma deposition and processing with very high frequency excitation  

SciTech Connect

The interest in plasma deposition using very high frequency (VHF) excitation arose after the preparation of a-Si:H at high growth rates was demonstrated. Subsequently the improved process flexibility and the control of material properties offered by the variation of the plasma excitation frequency was recognized. The preparation of amorphous and microcrystalline thin films in a VHF-plasma is described. The increased growth rates have been attributed to an enhancement of film precursor formation at VHF, to the decreased sheath thickness as well as to an enhancement of the surface reactivity by positive ions. Plasma diagnostic investigations show that the parameters mainly affected by the excitation frequency are the ion flux to the electrodes as well as the sheaths potentials and widths, rather than the plasma density. 55 refs., 13 figs.

Heintze, M.

1997-07-01

341

High energy resolution x-ray spectrometer for high count rate XRF applications  

SciTech Connect

A new x-ray spectrometer has been constructed which incorporates a novel large area, low capacitance Si(Li) detector and a low noise JFET (junction field effect transistor) pr- eamplifier. The spectrometer operates at high count rates without the conventional compromise in energy resolution. For example, at an amplifier peaking time of 1 {mu}sec and a throughput count rate of 145,000 counts sec{sup {minus}1}, the energy resolution at 5.9 key is 220 eV FWHM. Commercially available spectrometers utilizing conventional geometry Si(Li) detectors with areas equivalent to the new detector have resolutions on the order of 540 eV under the same conditions. Conventional x-ray spectrometers offering high energy resolution must employ detectors with areas one-tenth the size of the new LBL detector (20 mm{sup 2} compared with 200 mm{sup 2}). However, even with the use of the smaller area detectors, the energy resolution of a commercial system is typically limited to approximately 300 eV (again, at 1 {mu}sec and 5.9 keV) due to the noise of the commercially available JFET`S. The new large area detector is useful in high count rate applications, but is also useful in the detection of weak photon signals, in which it is desirable to subtend as large an angle of the available photon flux as possible, while still maintaining excellent energy resolution. X-ray fluorescence data from the new spectrometer is shown in comparison to a commercially available system in the analysis of a dilute multi-element material, and also in conjunction with high count rate synchrotron EXAMS applications.

Rossington, C.S.; Madden, N.W.; Chapman, K.

1993-08-01

342

Compact, high-repetition-rate OPCPA system for high harmonic generation  

NASA Astrophysics Data System (ADS)

A compact, high-repetition rate optical parametric chirped pulse amplifier system emitting CEP-stable, few-cycle pulses with 10 ?J of pulse energy is reported for the purpose of high-order harmonic generation. The system is seeded from a commercially available, CEP-stabilized Ti:sapphire oscillator, delivering an octave-spanning spectrum from 600-1200 nm. The oscillator output serves on the one hand as broadband signal for the parametric amplification process and on the other hand as narrowband seed for an Ytterbium-based fiber preamplifier with subsequent main amplifiers and frequency doubling. Broadband parametric amplification up to 17 ?J at 200 kHz repetition rate was achieved in two 5 mm BBO crystals using non-collinear phase matching in the Poynting-vector-walk-off geometry. Efficient pulse compression down to 6.3 fs is achieved with chirped mirrors leading to a peak power exceeding 800 MW. We observed after warm-up time a stability of < 0.5 % rms over 100 min. Drifts of the CE-phase in the parametric amplifier part could be compensated by a slow feedback to the set point of the oscillator phase lock. The CEP stability was measured to be better than 80 mrad over 15 min (3 ms integration time). The experimentally observed output spectra and energies could be well reproduced by simulations of the parametric amplification process based on a (2+1)-dimensional nonlinear propagation code, providing important insight for future repetition rate scaling of OPCPA systems. The system is well-suited for attosecond science experiments which benefit from the high repetition rate. First results for high-order harmonic generation in argon will be presented.

Matyschok, Jan; Binhammer, Thomas; Lang, Tino; Prochnow, Oliver; Rausch, Stefan; Rudawski, Piotr; Harth, Anne; Miranda, Miguel; Guo, Chen; Lorek, Eleonora; Mauritsson, Johan; Arnold, Cord L.; L'Huillier, Anne; Morgner, Uwe

2014-03-01

343

Effects of stocking rate on pasture production, milk production and reproduction of supplemented crossbred Holstein–Jersey dairy cows grazing lucerne pasture  

Microsoft Academic Search

Effects of stocking rates of 1.6, 2.1 and 2.6cows\\/ha on farm efficiency were evaluated using 92 crossbred Holstein–Jersey cows in a completely randomised design for 2yr in Argentina. A 44.1ha farm was divided into three farmlets and one spring calving herd was allocated to each. Cows grazed on lucerne based pastures (Medicago sativa L.) and were supplemented with high tannin

J. Baudracco; N. Lopez-Villalobos; L. A. Romero; D. Scandolo; M. Maciel; E. A. Comeron; C. W. Holmes; T. N. Barry

2011-01-01

344

High data rate degradation and medium thermal stability in ultra-high density magnetic recording  

NASA Astrophysics Data System (ADS)

In this dissertation, two major issues in the ultra-high density magnetic recording, the high data rate degradation and the medium thermal stability have been investigated. The high linear density together with the increasing rotational speed makes the high recording data rate inevitable. However, it has been found that the recording performance degrades at high data rates. While in order to maintain a sufficient signal-to-noise ratio (SNR) at high areal density, the grain size in the magnetic layer needs to be reduced, the small grain volume makes the magnetization data pattern in the media become unstable under thermal agitation and affect the lifetime of storage dramatically. By directly measuring the recording bubble footprint, the dynamic recording process was first characterized. In the light of the dynamic recording process, a complete understanding of the overwrite degradation in high speed recording has been obtained. Correlating with the nonlinear head response, the recording degradations at high data rate have been systematically investigated. By comparing the recording characteristics using different drive current waveforms, the effects of the field rise time and the head saturation have been understood. A novel spin-stand based technique has been developed to characterize the thermal stability of recording media. The statistics of effective energy barrier distribution have been obtained by directly measuring the remanent magnetization decay in a short time scale by applying proper reverse fields. The results also indicate that magnetic interactions have significant impact on energy barrier distribution and the magnetization decay process. To study the effect of magnetic interactions on the media thermal stability, a statistical model, which takes into account the magnetic interactions, has been developed. The effective energy barrier has been found to be reduced by the presence of interactions. Increasing the exchange coupling helps to improve the thermal stability of the recording medium. A non-zero weak exchange coupling may be desirable considering both medium SNR and thermal stability. The impacts of the medium orientation and the grain size distribution have also been studied.

Shi, Rick Changqing

345

High strain rate properties of unidirectional composites, part 1  

NASA Technical Reports Server (NTRS)

Experimental methods were developed for testing and characterization of composite materials at strain rates ranging from quasi-static to over 500 s(sup -1). Three materials were characterized, two graphite/epoxies and a graphite/S-glass/epoxy. Properties were obtained by testing thin rings 10.16 cm (4 in.) in diameter, 2.54 cm (1 in.) wide, and six to eight plies thick under internal pressure. Unidirectional 0 degree, 90 degree, and 10 degree off-axis rings were tested to obtain longitudinal, transverse, and in-plane shear properties. In the dynamic tests internal pressure was applied explosively through a liquid and the pressure was measured with a calibrated steel ring. Strains in the calibration and specimen rings were recorded with a digital processing oscilloscope. The data were processed and the equation of motion solved numerically by the mini-computer attached to the oscilloscope. Results were obtained and plotted in the form of dynamic stress-strain curves. Longitudinal properties which are governed by the fibers do not vary much with strain rate with only a moderate (up to 20 percent) increase in modulus. Transverse modulus and strength increase sharply with strain rate reaching values up to three times the static values. The in-plane shear modulus and shear strength increase noticeably with strain rate by up to approximately 65 percent. In all cases ultimate strains do not vary significantly with strain rates.

Daniel, I. M.

1991-01-01

346

Electrochemical corrosion rate probes for high temperature energy applications  

SciTech Connect

Electrochemical corrosion rate (ECR) probes were constructed and exposed along with mass loss coupons in a N2/O2/CO2/H2O environment to determine ECR probe operating characteristics. Temperatures ranged from 450 to 800 C and both ECR probes and mass loss coupons were coated with ash. Results are presented in terms of the probe response to temperature, the measured zero baseline, and the quantitative nature of the probes. The effect of Stern-Geary constant and the choice of electrochemical technique used to measure the corrosion rate are also discussed. ECR probe corrosion rates were a function of time, temperature, and process environment and were found to be quantitative for some test conditions. Measured Stern-Geary constants averaged 0.0141 V/decade and the linear polarization technique was found to be more quantitative than the electrochemical noise technique.

Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Holcomb, Gordon R.; Ziomek-Moroz, M.; Cayard, M.S. (InterCorr International Inc.); Eden, D.A. (InterCorr International Inc.)

2004-01-01

347

Pioneer spacecraft operation at low and high spin rates  

NASA Technical Reports Server (NTRS)

The feasibility of executing major changes upward or downward from the nominal spin rate for which the Pioneer F&G spacecraft was designed was investigated along with the extent of system and subsystem modifications required to implement these mode changes in future spacecraft evolving from the baseline Pioneer F and G. Results of a previous study are re-examined and updated for an extended range of spin rate variations for missions that include outer planet orbiters, outer planet flyby and outer planet probe delivery. However, in the interest of design simplicity and cost economy, major modifications of the baseline Pioneer system and subsystem concept were avoided.

1973-01-01

348

Alternate reproductive strategies in the California gull  

Microsoft Academic Search

Summary  We analysed 6 years of reproduction data for 176 California gulls (Larus californicus) surviving from 1980 to 1988. Using a statistical model adapted from Rao's (1958) and Tucker's (1966) generalized growth curve analysis, we reconstructed the reproductive patterns of gulls aged from 0 to 26 years. Individuals were highly consistent in following one of two patterns of reproduction. In a

B. H. Pugesek; P. Wood

1992-01-01

349

The basic reproductive ratio of life  

PubMed Central

Template-directed polymerization of nucleotides is believed to be a pathway for the replication of genetic material in the earliest cells. We assume that activated monomers are produced by prebiotic chemistry. These monomers can undergo spontaneous polymerization, a system that we call “prelife.” Adding template-directed polymerization changes the equilibrium structure of prelife if the rate constants meet certain criteria. In particular, if the basic reproductive ratio of sequences of a certain length exceeds one, then those sequences can attain high abundance. Furthermore, if many sequences replicate, then the longest sequences can reach high abundance even if the basic reproductive ratios of all sequences are less than one. We call this phenomenon “subcritical life.” Subcritical life suggests that sequences long enough to be ribozymes can become abundant even if replication is relatively inefficient. Our work on the evolution of replication has interesting parallels to infection dynamics. Life (replication) can be seen as an infection of prelife. PMID:20034501

Manapat, Michael L.; Chen, Irene A.; Nowak, Martin A.

2010-01-01

350

The high-rate behavior of parallel mesh chambers  

Microsoft Academic Search

Gas counters made from parallel metallic wire meshes have been proposed by Charpak et al. (1978) long ago as a preamplifying stage to wire chambers and developed meanwhile by many workers. The concept led to very robust and versatile detectors, having evolved over time to include complex multistep structures. It is known that parallel geometry chambers can stand counting rates

I. Ivaniouchenkov; P. Fonte; V. Peskov; R. Ferreira-Marques; A. Policarpo

1998-01-01

351

High-bit-rate continuous-variable quantum key distribution  

NASA Astrophysics Data System (ADS)

Here, we demonstrate that a practical continuous-variable quantum key distribution (QKD) protocol relying on the Gaussian modulation of coherent states features secret key rates that cannot be achieved with standard qubit discrete-variable QKD protocols. Notably, we report a practical postprocessing that allows us to extract more than 1 bit of secret key per channel use.

Jouguet, Paul; Elkouss, David; Kunz-Jacques, Sébastien

2014-10-01

352

Six Habits of the Highly Effective E-Rate Applicant  

ERIC Educational Resources Information Center

Since its inception in 1997, the Schools and Libraries Program of the Federal Communications Commission's Universal Service Fund, more commonly known as E-Rate, has committed more than $30 billion to offset the cost of certain digital and telecommunication services and products that are essential for schools and libraries to receive…

Harrington, John

2011-01-01

353

High Strain Rate Tensile Testing of DOP-26 Iridium  

SciTech Connect

The iridium alloy DOP-26 was developed through the Radioisotope Power Systems Program in the Office of Nuclear Energy of the Department of Energy. It is used for clad vent set cups containing radioactive fuel in radioisotope thermoelectric generator (RTG) heat sources which provide electric power for spacecraft. This report describes mechanical testing results for DOP-26. Specimens were given a vacuum recrystallization anneal of 1 hour at 1375 C and tested in tension in orientations parallel and perpendicular to the rolling direction of the sheet from which they were fabricated. The tests were performed at temperatures ranging from room temperature to 1090 C and strain rates ranging from 1 x 10{sup -3} to 50 s{sup -1}. Room temperature testing was performed in air, while testing at elevated temperatures was performed in a vacuum better than 1 x 10{sup -4} Torr. The yield stress (YS) and the ultimate tensile stress (UTS) decreased with increasing temperature and increased with increasing strain rate. Between 600 and 1090 C, the ductility showed a slight increase with increasing temperature. Within the scatter of the data, the ductility did not depend on the strain rate. The reduction in area (RA), on the other hand, decreased with increasing strain rate. The YS and UTS values did not differ significantly for the longitudinal and transverse specimens. The ductility and RA values of the transverse specimens were marginally lower than those of the longitudinal specimens.

Schneibel, Joachim H [ORNL; Carmichael Jr, Cecil Albert [ORNL; George, Easo P [ORNL

2007-11-01

354

Phase Change Disc for High Data Rate Recording  

Microsoft Academic Search

We have developed a phase change disc having a thin transparent cover layer corresponding to the new optical recording system (DVR) using a blue laser (405 nm) and a numerical aperture (NA) of 0.85. We have achieved a user capacity of 22 GB per side of the 120 mm diameter disc, and a user data recording rate of 70 Mbps

Hiroyasu Inoue; Hideki Hirata; Tatsuya Kato; Hiroshi Shingai; Hajime Utsunomiya

2001-01-01

355

Assessment of Early Postpartum Reproductive Performance in Two High Producing Estonian Dairy Herds  

PubMed Central

Early postpartum (6 weeks) ovarian activity, hormonal profiles, uterine involution, uterine infections, serum electrolytes, glucose, milk acetoacetate and blood urea nitrogen (BUN) levels were studied in 2 Estonian high producing dairy herd with annual milk production of 7688 (Farm A) and 9425 (Farm B). From each farm 10 cows, with normal calving performance were used. Blood samples for the hormonal (PGF2?-metabolite, progesterone) analyses were withdrawn. On day 25 PP blood serum samples were taken for the evaluation of metabolic/electrolyte status. On the same day estimation of milk acetoacetate values was done. The ultrasound (US) was started on day 7 PP and was performed every 3rd day until the end of experiment. Uterine content, follicular activity and sizes of the largest follicle and corpus luteum were monitored and measured. Vaginal discharge and uterine tone were recorded during the rectal palpation. Each animal in the study was sampled for bacteriological examination using endometrial biopsies once a week. Two types of PGF2?-metabolite patterns were detected: elevated levels during 14 days PP, then decline to the basal level and then a second small elevation at the time of final elimination of the bacteria from the uterus; or elevated levels during first 7 days PP, then decline to the basal level and a second small elevation before the final elimination of bacteria. Endometritis was diagnosed in 5 cows in farm A and in 3 cows in farm B respectively. In farm A, 5 cows out of 10 ovulated during experimental period and in 1 cow cystic ovaries were found. In farm B, 3 cows out of 10 ovulated. In 3 cows cystic ovaries were found. Altogether 40% of cows had their first ovulation during the experimental period. Three cows in farm A and 5 cows in farm B were totally bacteria negative during the experimental period. The most frequent bacteria found were A. pyogenes, Streptococcus spp., E. coli., F. necrophorum and Bacteroides spp. The highest incidence of bacteriological species was found during the first 3 weeks in both farms. All animals were free from bacteria after 5th week PP in farm A and after 4th week in farm B respectively. Serum electrolytes and glucose levels were found to be within the reference limits for the cows in both farms. No significant difference was found between farms (p > 0.05). Low phosphorus levels were found in both farms. Significant difference (p < 0.05) was found in BUN levels between farms. In both farms milk acetoacetate values were staying within the reference range given for the used test (<100 ?mol/l). The uterine involution and bacterial elimination in the investigated cows could consider as normal but more profound metabolic studies could be needed to find reasons for later resumption of ovarian activity. Some recommendations to changing feeding regimes and strategies should also be given. PMID:15074626

Kask, K; Kurykin, J; Lindjärv, R; Kask, A; Kindahl, H

2003-01-01

356

REPRODUCTIVE DEVELOPMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Throughout history, humans have celebrated the beauty and fertility of flowering plants. In addition to their aesthetic appeal, flowers contain the reproductive organs of the plant and are therefore essential for sexual propagation of plant life. Our dependence on flowering is illustrated by the die...

357

Influence of temperature on the high-strain-rate mechanical behavior of PBX 9501  

Microsoft Academic Search

High-strain-rate (2000 s?1) compression measurements utilizing a specially-designed Split-Hopkinson-Pressure Bar have been obtained as a function of temperature from ?55 to +50 °C for the plastic-bonded explosive PBX 9501. The PBX 9501 high-strain-rate data was found to exhibit similarities to other energetic, propellant, and polymer-composite materials as a function of strain rate and temperature. The high-rate response of the energetic

G. T. Gray; W. R. Blumenthal; D. J. Idar; C. M. Cady

1998-01-01

358

Influence of temperature on the high-strain-rate mechanical behavior of PBX 9501  

Microsoft Academic Search

High-strain-rate (2000 s-1) compression measurements utilizing a specially-designed Split-Hopkinson-Pressure Bar have been obtained as a function of temperature from -55 to +50 °C for the plastic-bonded explosive PBX 9501. The PBX 9501 high-strain-rate data was found to exhibit similarities to other energetic, propellant, and polymer-composite materials as a function of strain rate and temperature. The high-rate response of the energetic

G. T. Gray; W. R. Blumenthal; D. J. Idar; C. M. Cady

1998-01-01

359

Mechanical model for yield strength of nanocrystalline materials under high strain rate loading  

Microsoft Academic Search

To understand the high strain rate deformation mechanism and determine the grain size, strain rate and porosity dependent\\u000a yield strength of nanocrystalline materials, a new mechanical model based on the deformation mechanism of nanocrystalline\\u000a materials under high strain rate loading was developed. As a first step of the research, the yield behavior of the nanocrystalline\\u000a materials under high strain rate

Rong-tao Zhu; Jian-qiu Zhou; Lu Ma; Zhen-zhong Zhang

2008-01-01

360

Terminal Investment: Individual Reproduction of Ant Queens Increases with Age  

PubMed Central

The pattern of age-specific fecundity is a key component of the life history of organisms and shapes their ecology and evolution. In numerous animals, including humans, reproductive performance decreases with age. Here, we demonstrate that some social insect queens exhibit the opposite pattern. Egg laying rates of Cardiocondyla obscurior ant queens increased with age until death, even when the number of workers caring for them was kept constant. Cardiocondyla, and probably also other ants, therefore resemble the few select organisms with similar age-specific reproductive investment, such as corals, sturgeons, or box turtles (e.g., [1]), but they differ in being more short-lived and lacking individual, though not social, indeterminate growth. Furthermore, in contrast to most other organisms, in which average life span declines with increasing reproductive effort, queens with high egg laying rates survived as long as less fecund queens. PMID:22509399

Heinze, Jürgen; Schrempf, Alexandra

2012-01-01

361

An assessment of high-power light-emitting diodes for high frame rate schlieren imaging  

NASA Astrophysics Data System (ADS)

The feasibility of using high-power light-emitting diodes (LED) as a light source for high frame rate schlieren imaging is investigated. Continuous sequences of high-intensity light pulses are achieved by overdriving the LED with current pulses up to a factor of ten beyond its specifications. In comparison to commonly used pulsed light sources such as gas discharge lamps and pulsed lasers, the pulsed LED has several attractive advantages: the pulse-to-pulse intensity variation is on the same order of magnitude as the detector (camera) noise permitting quantitative intensity measurements. The LED's narrow emission bandwidth reduces chromatic abberations, yet it is spectrally wide enough to prevent the appearance of speckle and diffraction effects in the images. Most importantly, the essentially lag-free light emission within tens of nanoseconds of the applied current pulse allows the LED to be operated at varying frequencies (i.e., asynchronously), which generally is not possible with neither lasers nor discharge lamps. The pulsed LED source, driven by a simple driver circuit, is demonstrated on two schlieren imaging setups. The first configuration visualizes the temporal evolution of shock structures and sound waves of an under-expanded jet that is impinging on a rigid surface at frame rates of 500 kHz to 1 MHz. In a second application, long sequences of several thousand high-resolution images are acquired on a free jet at a frame rate of 1 kHz. The low-intensity fluctuation and large sample number allow a reliable computation of two-point correlation data from the image sequences.

Willert, Christian E.; Mitchell, Daniel M.; Soria, Julio

2012-08-01

362

Data compression techniques applied to high resolution high frame rate video technology  

NASA Technical Reports Server (NTRS)

An investigation is presented of video data compression applied to microgravity space experiments using High Resolution High Frame Rate Video Technology (HHVT). An extensive survey of methods of video data compression, described in the open literature, was conducted. The survey examines compression methods employing digital computing. The results of the survey are presented. They include a description of each method and assessment of image degradation and video data parameters. An assessment is made of present and near term future technology for implementation of video data compression in high speed imaging system. Results of the assessment are discussed and summarized. The results of a study of a baseline HHVT video system, and approaches for implementation of video data compression, are presented. Case studies of three microgravity experiments are presented and specific compression techniques and implementations are recommended.

Hartz, William G.; Alexovich, Robert E.; Neustadter, Marc S.

1989-01-01

363

High invertase activity in tomato reproductive organs correlates with enhanced sucrose import into, and heat tolerance of, young fruit.  

PubMed

Heat stress can cause severe crop yield losses by impairing reproductive development. However, the underlying mechanisms are poorly understood. We examined patterns of carbon allocation and activities of sucrose cleavage enzymes in heat-tolerant (HT) and -sensitive (HS) tomato (Solanum lycopersicum L.) lines subjected to normal (control) and heat stress temperatures. At the control temperature of 25/20 °C (day/night) the HT line exhibited higher cell wall invertase (CWIN) activity in flowers and young fruits and partitioned more sucrose to fruits but less to vegetative tissues as compared to the HS line, independent of leaf photosynthetic capacity. Upon 2-, 4-, or 24-h exposure to day or night temperatures of 5 °C or more above 25/20 °C, cell wall (CWIN) and vacuolar invertases (VIN), but not sucrose synthase (SuSy), activities in young fruit of the HT line were significantly higher than those of the HS line. The HT line had a higher level of transcript of a CWIN gene, Lin7, in 5-day fruit than the HS line under control and heat stress temperatures. Interestingly, heat induced transcription of an invertase inhibitor gene, INVINH1, but reduced its protein abundance. Transcript levels of LePLDa1, encoding phospholipase D, which degrades cell membranes, was less in the HT line than in the HS line after exposure to heat stress. The data indicate that high invertase activity of, and increased sucrose import into, young tomato fruit could contribute to their heat tolerance through increasing sink strength and sugar signalling activities, possibly regulating a programmed cell death pathway. PMID:22105847

Li, Zhimiao; Palmer, William M; Martin, Antony P; Wang, Rongqing; Rainsford, Frederick; Jin, Ye; Patrick, John W; Yang, Yuejian; Ruan, Yong-Ling

2012-02-01

364

Highly Divergent Strains of Porcine Reproductive and Respiratory Syndrome Virus Incorporate Multiple Isoforms of Nonstructural Protein 2 into Virions  

PubMed Central

Viral structural proteins form the critical intermediary between viral infection cycles within and between hosts, function to initiate entry, participate in immediate early viral replication steps, and are major targets for the host adaptive immune response. We report the identification of nonstructural protein 2 (nsp2) as a novel structural component of the porcine reproductive and respiratory syndrome virus (PRRSV) particle. A set of custom ?-nsp2 antibodies targeting conserved epitopes within four distinct regions of nsp2 (the PLP2 protease domain [OTU], the hypervariable domain [HV], the putative transmembrane domain [TM], and the C-terminal region [C]) were obtained commercially and validated in PRRSV-infected cells. Highly purified cell-free virions of several PRRSV strains were isolated through multiple rounds of differential density gradient centrifugation and analyzed by immunoelectron microscopy (IEM) and Western blot assays using the ?-nsp2 antibodies. Purified viral preparations were found to contain pleomorphic, predominantly spherical virions of uniform size (57.9 nm ± 8.1 nm diameter; n = 50), consistent with the expected size of PRRSV particles. Analysis by IEM indicated the presence of nsp2 associated with the viral particle of diverse strains of PRRSV. Western blot analysis confirmed the presence of nsp2 in purified viral samples and revealed that multiple nsp2 isoforms were associated with the virion. Finally, a recombinant PRRSV genome containing a myc-tagged nsp2 was used to generate purified virus, and these particles were also shown to harbor myc-tagged nsp2 isoforms. Together, these data identify nsp2 as a virion-associated structural PRRSV protein and reveal that nsp2 exists in or on viral particles as multiple isoforms. PMID:24089566

Kappes, Matthew A.; Miller, Cathy L.

2013-01-01

365

Graphics processing unit accelerated optical coherence tomography processing at megahertz axial scan rate and high resolution video rate volumetric rendering  

NASA Astrophysics Data System (ADS)

In this report, we describe how to highly optimize a computer unified device architecture based platform to perform real-time processing of optical coherence tomography interferometric data and three-dimensional (3-D) volumetric rendering using a commercially available, cost-effective, graphics processing unit (GPU). The maximum complete attainable axial scan processing rate, including memory transfer and displaying B-scan frame, was 2.24 MHz for 16 bits pixel depth and 2048 fast Fourier transform size; the maximum 3-D volumetric rendering rate, including B-scan, en face view display, and 3-D rendering, was ˜23 volumes/second (volume size: 1024×256×200). To the best of our knowledge, this is the fastest processing rate reported to date with a single-chip GPU and the first implementation of real-time video-rate volumetric optical coherence tomography (OCT) processing and rendering that is capable of matching the acquisition rates of ultrahigh-speed OCT.

Jian, Yifan; Wong, Kevin; Sarunic, Marinko V.

2013-02-01

366

Transmission rates of the bacterial endosymbiont, Neorickettsia risticii, during the asexual reproduction phase of its digenean host, Plagiorchis elegans, within naturally infected lymnaeid snails  

PubMed Central

Background Neorickettsia are obligate intracellular bacterial endosymbionts of digenean parasites present in all lifestages of digeneans. Quantitative information on the transmission of neorickettsial endosymbionts throughout the complex life cycles of digeneans is lacking. This study quantified the transmission of Neorickettsia during the asexual reproductive phase of a digenean parasite, Plagiorchis elegans, developing within naturally parasitized lymnaeid pond snails. Methods Lymnaea stagnalis snails were collected from 3 ponds in Nelson County, North Dakota and screened for the presence of digenean cercariae. Cercariae were identified to species by PCR and sequencing of the 28S rRNA gene. Neorickettsia infections were initially detected using nested PCR and sequencing of a partial 16S rRNA gene of pooled cercariae shed from each parasitized snail. Fifty to 100 single cercariae or sporocysts were isolated from each of six parasitized snails and tested for the presence of Neorickettsia using nested PCR to estimate the efficiency at which Neorickettsia were transmitted to cercariae during asexual development of the digenean. Results A total of 616?L. stagnalis were collected and 240 (39%) shed digenean cercariae. Of these, 18 (8%) were Neorickettsia-positive. Six Neorickettsia infections were selected to determine the transmission efficiency of Neorickettsia from mother to daughter sporocyst and from daughter sporocyst to cercaria. The prevalence of neorickettsiae in cercariae varied from 11 to 91%. The prevalence of neorickettsiae in sporocysts from one snail was 100%. Conclusion Prevalence of Neorickettsia infection in cercariae of Plagiorchis elegans was variable and never reached 100%. Reasons for this are speculative, however, the low prevalence of Neorickettsia observed in some of our samples (11 to 52%) differs from the high prevalence of other, related bacterial endosymbionts, e.g. Wolbachia in Wolbachia-dependent filariid nematodes, where the prevalence among progeny is universally 100%. This suggests that, unlike the Wolbachia-filaria relationship, the Neorickettsia-digenean relationship is not obligatory mutualism. Our study represents the first quantitative estimate of the Neorickettsia transmission through the asexual phase of the digenean life cycle. PMID:24383453

2013-01-01

367

High repetition rate pulsed power generator using IGBTs and magnetic pulse compression circuit  

Microsoft Academic Search

Recently, all solid-state pulsed power generators, which are operated with high repetition rate, long lifetime and high reliability, have been developed to be used for industrial applications, such as high repetition rate pulsed gas lasers, high energy density plasma (EUV sources) and pulse ozonizer. Requirements of these applications are repetitive fast rise time pulsed power. Recently, semiconductor power device technology

T. Sakugawa; K. Kouno; K. Kawamoto; H. Akiyama; K. Suematsu; A. Kouda; M. Watanabe

2009-01-01

368

School Characteristics Related to High School Dropout Rates  

ERIC Educational Resources Information Center

Dropping out of high school culminates a long-term process of disengagement from school and has profound social and economic consequences for students, their families, and their communities. Students who drop out of high school are more likely to be unemployed, to earn less than those who graduate, to be on public assistance, and to end up in…

Christle, Christine A.; Jolivette, Kristine; Nelson, C. Michael

2007-01-01

369

A crossbow system for high-strain-rate mechanical testing  

NASA Astrophysics Data System (ADS)

This paper describes a technique developed to measure the uniaxial compressive stress - strain properties of polymers at strain rates appropriate to ballistic and impact events over time scales of tens of microseconds using a crossbow as the projectile launch system. The instrument constructed represents a novel development of existing equipment types. The system is used for compression testing giving stress - strain measurements at strain rates of up to 0957-0233/7/7/011/img5 and over a temperature range of 0957-0233/7/7/011/img6. Stress is calculated directly from a measured force obtained from a calibrated pressure bar. Strain is calculated from the sample displacement measured directly from the intensity reduction of a laser-photodiode unit. The crossbow system provides a relatively inexpensive, reliable and compact alternative to a standard Hopkinson bar.

Hamdan, S.; Swallowe, G. M.

1996-07-01

370

High strength semi-active energy absorbers using shear- and mixedmode operation at high shear rates  

NASA Astrophysics Data System (ADS)

This body of research expands the design space of semi-active energy absorbers for shock isolation and crash safety by investigating and characterizing magnetorheological fluids (MRFs) at high shear rates ( > 25,000 1/s) under shear and mixed-mode operation. Magnetorheological energy absorbers (MREAs) work well as adaptive isolators due to their ability to quickly and controllably adjust to changes in system mass or impact speed while providing fail-safe operation. However, typical linear stroking MREAs using pressure-driven flows have been shown to exhibit reduced controllability as impact speed (shear rate) increases. The objective of this work is to develop MREAs that improve controllability at high shear rates by using pure shear and mixed shear-squeeze modes of operation, and to present the fundamental theory and models of MR fluids under these conditions. A proof of concept instrument verified that the MR effect persists in shear mode devices at shear rates corresponding to low speed impacts. This instrument, a concentric cylinder Searle cell magnetorheometer, was then used to characterize three commercially available MRFs across a wide range of shear rates, applied magnetic fields, and temperatures. Characterization results are presented both as flow curves according to established practice, and as an alternate nondimensionalized analysis based on Mason number. The Mason number plots show that, with appropriate correction coefficients for operating temperature, the varied flow curve data can be collapsed to a single master curve. This work represents the first shear mode characterization of MRFs at shear rates over 10 times greater than available with commercial rheometers, as well as the first validation of Mason number analysis to high shear rate flows in MRFs. Using the results from the magnetorheometer, a full scale rotary vane MREA was developed as part of the Lightweight Magnetorheological Energy Absorber System (LMEAS) for an SH-60 Seahawk helicopter crew seat. Characterization tests were carried out on the LMEAS using a 40 vol% MRF used in the previous magnetorheometer tests. These were analyzed using both flow curves and apparent viscosity vs. Mason number diagrams. The nondimensionalized Mason number analysis resulted in data for all conditions of temperature, fluid composition, and shear rate, to collapse onto a single characteristic or master curve. Significantly, the temperature corrected Mason number results from both the bench top magnetorheometer and full scale rotary vane MREA collapse to the same master curve. This enhances the ability of designers of MRFs and MREAs to safely and effectively apply characterization data collected in low shear rate, controlled temperature environments to operational environments that may be completely different. Finally, the Searle cell magnetorheometer was modified with an enforced eccentricity to work in both squeeze and shear modes simultaneously to achieve so called squeeze strengthening of the working MRF, thereby increasing the apparent yield stress and the specific energy absorption. By squeezing the active MR fluid, particles undergo compression-assisted aggregation into stronger, more robust columns which resist shear better than single chains. A hybrid model describing the squeeze strengthening behavior is developed, and recommendations are made for using squeeze strengthening to improve practical MREA devices.

Becnel, Andrew C.

371

Ultrafast high strain rate acoustic wave measurements at high static pressure in a diamond anvil cell  

SciTech Connect

We have used sub-picosecond laser pulses to launch ultra-high strain rate ({approx} 10{sup 9} s{sup -1}) nonlinear acoustic waves into a 4:1 methanol-ethanol pressure medium which has been precompressed in a standard diamond anvil cell. Using ultrafast interferometry, we have characterized acoustic wave propagation into the pressure medium at static compression up to 24 GPa. We find that the velocity is dependent on the incident laser fluence, demonstrating a nonlinear acoustic response which may result in shock wave behavior. We compare our results with low strain, low strain-rate acoustic data. This technique provides controlled access to regions of thermodynamic phase space that are otherwise difficult to obtain.

Armstrong, M; Crowhurst, J; Reed, E; Zaug, J

2008-02-04

372

High-rate copper dissolution in hydrochloric acid solution  

SciTech Connect

The dissolution of copper in 1 M chloride solution was studied by steady-state (current-potential curves for various disk rotation rates) and transient measurements [frequency analysis of the electrochemical and electrohydrodynamical (EHD) impedance]. The anodic polarization curves present four regions according to the potential: one region of mixed kinetics followed by another of mass-transport control characterized by one plateau, followed by a second mixed kinetics region and a second plateau. The results obtained for the first domain of mixed kinetics and for the first plateau were previously published. In this work, the second mixed kinetics region is considered. From the analysis of the ac and EHD impedance measurements, it was shown that a transition between the presence and the absence of a CuCl salt layer occurs at a critical potential. The value of this critical potential depends on the rotation rate; the higher the rotation rate, the higher the potential value. A model of kinetic dissolution for this transition is presented, and a coupling between the currents corresponding to the two reactions is demonstrated.

D`Elia, E.; Barcia, O.E.; Mattos, O.R. [UFRJ, Rio de Janeiro (Brazil); Pebere, N. [ENSCT, Toulouse (France). Equipe de Metallurgie Physique; Tribollet, B. [Physique des Liquides et Electrochimie, Paris (France)

1996-03-01

373

High temperature electronic excitation and ionization rates in gases  

NASA Technical Reports Server (NTRS)

The relaxation times for electronic excitation due to electron bombardment of atoms was found to be quite short, so that electron kinetic temperature (T sub e) and the electron excitation temperature (T asterisk) should equilibrate quickly whenever electrons are present. However, once equilibrium has been achieved, further energy to the excited electronic states and to the kinetic energy of free electrons must be fed in by collisions with heavy particles that cause vibrational and electronic state transitions. The rate coefficients for excitation of electronic states produced by heavy particle collision have not been well known. However, a relatively simple semi-classical theory has been developed here which is analytic up to the final integration over a Boltzmann distribution of collision energies; this integral can then be evaluated numerically by quadrature. Once the rate coefficients have been determined, the relaxation of electronic excitation energy can be evaluated and compared with the relaxation rates of vibrational excitation. Then the relative importance of these two factors, electronic excitation and vibrational excitation by heavy particle collision, on the transfer of energy to free electron motion, can be assessed.

Hansen, Frederick

1991-01-01

374

High intensity, high temporal contrast, high repetition-rate laser for laser driven particle acceleration  

NASA Astrophysics Data System (ADS)

We have demonstrated an optical parametric chirped pulse amplification (OPCPA)/Yb:YAG ceramic thin disk hybrid laser system having hundred mJ level pulse energy sub-picosecond pulse duration with high temporal contrast. At an input chirped-pulse energy of 3.8 mJ from an OPCPA preamplifer an output energy of 130 mJ has been generated from multipass laser diode-pumped Yb:YAG ceramic thin disk amplifier. A recompressed pulse duration of 450 fs with a contrast level of less than 7.2×10-9 at -150 ps before the main pulse has been obtained. The contrast level is the highest value achieved in Yb:YAG chirped pulse amplification (CPA) laser system with hundred mJ level.

Suzuki, M.; Kiriyama, H.; Daito, I.; Okada, H.; Ochi, Y.; Sato, M.; Yoshii, T.; Tamaoki, Y.; Maeda, J.; Matsuoka, S.; Kan, H.; Bolton, P. R.; Sugiyama, A.; Kondo, K.; Kawanishi, S.

2012-07-01

375

Faking giants: the evolution of high prey clearance rates in jellyfishes.  

PubMed

Jellyfishes have functionally replaced several overexploited commercial stocks of planktivorous fishes. This is paradoxical, because they use a primitive prey capture mechanism requiring direct contact with the prey, whereas fishes use more efficient visual detection. We have compiled published data to show that, in spite of their primitive life-style, jellyfishes exhibit similar instantaneous prey clearance and respiration rates as their fish competitors and similar potential for growth and reproduction. To achieve this production, they have evolved large, water-laden bodies that increase prey contact rates. Although larger bodies are less efficient for swimming, optimization analysis reveals that large collectors are advantageous if they move through the water sufficiently slowly. PMID:21921197

Acuña, José Luis; López-Urrutia, Ángel; Colin, Sean

2011-09-16

376

INLINE HIGH-RATE THERMAL EVAPORATION OF ALUMINUM FOR NOVEL INDUSTRIAL SOLAR CELL METALLIZATION  

E-print Network

INLINE HIGH-RATE THERMAL EVAPORATION OF ALUMINUM FOR NOVEL INDUSTRIAL SOLAR CELL METALLIZATION F, Appelstrasse 2, 30167 Hannover, Germany ABSTRACT: We evaluate a novel high-throughput thermal evaporation deposition rates of up to 5 µm � m/min. By adjusting the individual aluminium evaporation rate for each

377

The Use of High School Faculty Ratings to Predict USMA Fourth Class Performance.  

ERIC Educational Resources Information Center

The potential use of High School Faculty Ratings for admission purposes is investigated. The ratings include the evaluations of a candidate on 10 traits and three overall characteristics. The rating forms are given to a mathematics, English, and physical education teacher, a counselor or high school principal, and one other faculty member by the…

McLaughlin, Gerald W.

378

Finite Rate Chemistry Effects in Highly Sheared Turbulent Premixed Flames  

Microsoft Academic Search

Detailed scalar structure measurements of highly sheared turbulent premixed flames stabilized on the piloted premixed jet\\u000a burner (PPJB) are reported together with corresponding numerical calculations using a particle based probability density function\\u000a (PDF) method. The PPJB is capable of stabilizing highly turbulent premixed jet flames through the use of a small stoichiometric\\u000a pilot that ensures initial ignition of the jet

Matthew J. Dunn; Assaad R. Masri; Robert W. Bilger; Robert S. Barlow

2010-01-01

379

High Rate of Sexual Dysfunction Following Surgery for Rectal Cancer  

PubMed Central

Purpose Although rectal cancer is a very common malignancy and has an improved cure rate in response to oncological treatment, research on rectal-cancer survivors' sexual function remains limited. Sexual dysfunction (SD) after rectal cancer treatment was measured, and possible predisposing factors that may have an impact on the development of this disorder were identified. Methods Patients undergoing curative rectal cancer surgery from January 2012 to September 2013 were surveyed using questionnaires. The female sexual function index or the International Index of Erectile Function was recorded. A multiple logistic regression was used to test associations of clinical factors with outcomes. Results Fifty-six men (56%) and 28 women (44%) who completed the questionnaire were included in the study. A total of 76 patients of the 86 patients (90.5%) with the diagnosis of rectal cancer who were included in this study reported different levels of SD after radical surgery. A total of 64 patients (76%) from the whole cohort reported moderate to severe SD after treatment of rectal cancer. Gender (P = 0.011) was independently associated with SD. Female patients reported significantly higher rates of moderate to severe SD than male patients. Patients were rarely treated for dysfunction. Conclusion Sexual problems after surgery for rectal cancer are common, but patients are rarely treated for SD. Female patients reported higher rates of SD than males. These results point out the importance of sexual (dys)function in survivors of rectal cancer. More attention should be drawn to this topic for clinical and research purposes. PMID:25360427

Ertekin, Caglar; Tinay, Ilker; Yegen, Cumhur

2014-01-01

380

High strain rate properties and constitutive modeling of glass  

SciTech Connect

This paper presents experimental data and computational modeling for a well-defined glass material. The experimental data cover a wide range of strains, strain rates, and pressures that are obtained from quasi-static compression and tension tests, split Hopkinson pressure bar compression tests, explosively driven flyer plate impact tests, and depth of penetration ballistic tests. The test data are used to obtain constitutive model constants for the improved Johnson-Holmquist (JH-2) brittle material model. The model and constants are then used to perform computations of the various tests.

Holmquist, T.J.; Johnson, G.R.; Lopatin, C.M. [Alliant Techsystems Inc., Hopkins, MN (United States); Grady, D.E.; Hertel, E.S. Jr. [Sandia National Labs., Albuquerque, NM (United States)

1995-03-01

381

High rates of substance use in French youths 13/7/07 High prevalence rates of tobacco, alcohol and drug use in adolescents and  

E-print Network

-specific rates of substance (tobacco, alcohol, cannabis, other illicit drugs, inhalants and psychotropic: Prevalence rates of substance use were high and varied with age and sex. Tobacco, cannabis and polysubstance; regular cannabis use: respectively 23.9% and 10.9%; tobacco + alcohol + cannabis: respectively 9.9% and 4

Paris-Sud XI, Université de

382

A 4-GHz QPSK modulator for high bit rates  

NASA Astrophysics Data System (ADS)

A 4-GHz microwave integrated circuit, quadrature phase-shift keying (QPSK) modulator has been developed for 120-Mbit/s data rates. The measured phase and amplitude balance are within + or - 1 deg and + or - 0.15 dB, respectively, over a 200-MHz bandwidth. The measured rise time of a typical phase-state transition is less than 1.5 ns. These features guarantee good performance at bit rates even higher than 120 Mbit/s. The QPSK modulation is achieved by driving two balanced binary phase-shift keying (BPSK) modulators in parallel and using a 90 deg, 3-dB hybrid to combine their outputs. The BPSK modulators have been designed using a different approach, and each exhibits an excellent amplitude balance, + or - 0.1 dB, and a phase balance of + or - 0.5 deg over the 200-MHz bandwidth. The QPSK modulator is laid out on a 1.8 x 2.3-in. alumina substrate. It is directly compatible with standard emitter-coupled logic gate drivers. Its size, power consumption, and weight make it suitable for use in a spacecraft regenerative modem.

Karimullah, K.; Egri, R. G.

383

Comparison of RBE values of high- LET ?-particles for the induction of DNA-DSBs, chromosome aberrations and cell reproductive death  

PubMed Central

Background Various types of radiation effects in mammalian cells have been studied with the aim to predict the radiosensitivity of tumours and normal tissues, e.g. DNA double strand breaks (DSB), chromosome aberrations and cell reproductive inactivation. However, variation in correlations with clinical results has reduced general application. An additional type of information is required for the increasing application of high-LET radiation in cancer therapy: the Relative Biological Effectiveness (RBE) for effects in tumours and normal tissues. Relevant information on RBE values might be derived from studies on cells in culture. Methods To evaluate relationships between DNA-DSB, chromosome aberrations and the clinically most relevant effect of cell reproductive death, for ionizing radiations of different LET, dose-effect relationships were determined for the induction of these effects in cultured SW-1573 cells irradiated with gamma-rays from a Cs-137 source or with ?-particles from an Am-241 source. RBE values were derived for these effects. Ionizing radiation induced foci (IRIF) of DNA repair related proteins, indicative of DSB, were assessed by counting gamma-H2AX foci. Chromosome aberration frequencies were determined by scoring fragments and translocations using premature chromosome condensation. Cell survival was measured by colony formation assay. Analysis of dose-effect relations was based on the linear-quadratic model. Results Our results show that, although both investigated radiation types induce similar numbers of IRIF per absorbed dose, only a small fraction of the DSB induced by the low-LET gamma-rays result in chromosome rearrangements and cell reproductive death, while this fraction is considerably enhanced for the high-LET alpha-radiation. Calculated RBE values derived for the linear components of dose-effect relations for gamma-H2AX foci, cell reproductive death, chromosome fragments and colour junctions are 1.0 ± 0.3, 14.7 ± 5.1, 15.3 ± 5.9 and 13.3 ± 6.0 respectively. Conclusions These results indicate that RBE values for IRIF (DNA-DSB) induction provide little valid information on other biologically-relevant end points in cells exposed to high-LET radiations. Furthermore, the RBE values for the induction of the two types of chromosome aberrations are similar to those established for cell reproductive death. This suggests that assays of these aberrations might yield relevant information on the biological effectiveness in high-LET radiotherapy. PMID:21651780

2011-01-01

384

Comparison of social support content within online communities for high- and low-survival-rate cancers.  

PubMed

People experiencing cancer use the Internet for many reasons, particularly for social support. This study sought to determine how social support content within online support communities for different cancers varied according to cancer survival rate. A quantitative content analysis was conducted on 3717 posts from eight online communities focused on cancers with high and low 5-year relative survival rates. Using Optimal Matching Theory, we predicted that low-survival-rate communities would have more emotional support content than high-survival-rate communities, and high-survival-rate communities would have more informational support content than low-survival-rate communities. Emotional support content was consistently more common than informational support. Overall, high-survival-rate communities had a greater proportion of posts containing emotional support content (75%) than low-survival-rate communities (66%) (?1 = 20.89 [n = 2235], P < .001). Furthermore, low-survival-rate communities had a greater proportion of posts containing informational support content (46%) than high-survival-rate communities (36%) (?1 = 21.13 [n = 2235], P< .001). Although the relationships between survival rate and support types were significant, they were not as hypothesized. Deviations from theoretically predicted results suggest that individuals experiencing low-survival-rate cancers may have a greater desire for informational support online than individuals experiencing high-survival-rate cancers. PMID:21876394

Buis, Lorraine R; Whitten, Pamela

2011-08-01

385

High-strain, high-strain-rate flow and failure in PTFE\\/Al\\/W granular composites  

Microsoft Academic Search

Dynamic compression experiments were performed on a pressed PTFE\\/Al\\/W mixture to understand the composite behavior at high-strain and high-strain rate. The high-strain-rate tests were carried out in a drop-weight apparatus at impact velocities of 3.5 and 5m\\/s, providing strain rates of approximately 4×102s?1. Aluminum jackets of varying thickness were used to ensure that specimens underwent confined deformation but did not

J. Cai; S. M. Walley; R. J. A. Hunt; W. G. Proud; V. F. Nesterenko; M. A. Meyers

2008-01-01

386

Evaluation of components, subsystems, and networks for high rate, high frequency space communications  

NASA Technical Reports Server (NTRS)

The development of new space communications technologies by NASA has included both commercial applications and space science requirements. NASA's Systems Integration, Test and Evaluation (SITE) Space Communication System Simulator is a hardware based laboratory simulator for evaluating space communications technologies at the component, subsystem, system, and network level, geared toward high frequency, high data rate systems. The SITE facility is well-suited for evaluation of the new technologies required for the Space Exploration Initiative (SEI) and advanced commercial systems. Described here are the technology developments and evaluation requirements for current and planned commercial and space science programs. Also examined are the capabilities of SITE, the past, present and planned future configurations of the SITE facility, and applications of SITE to evaluation of SEI technology.

Kerczewski, Robert J.; Ivancic, William D.; Zuzek, John E.

1991-01-01

387

Study of microvoids in high-rate a-Si:H using positron annihilation  

SciTech Connect

In this paper, the authors have carried out the positron annihilation measurement on high-rate and low-rate a-Si:H thin films deposited by PECVD. By means of the slow positron beam Doppler-broadening technique, the depth profiles of microvoids in a-Si:H have been determined. They have also studied the vacancy-type defect in the surface region in high-rate grown a-Si:H, making comparison between high-rate and low-rate a-Si:H. By plotting S and W parameters in the (S, W) plane, they have shown that the vacancies in all of the high-rate and low-rate deposited intrinsic samples, and in differently doped low-rate samples are of the same nature.

Zou, X.; Webb, D.P.; Lin, S.H.; Lam, Y.W.; Chan, Y.C.; Hu, Y.F.; Beling, C.D.; Fung, S.

1997-07-01

388

14 CFR 65.20 - Applications, certificates, logbooks, reports, and records: Falsification, reproduction, or...  

Code of Federal Regulations, 2011 CFR

...reports, and records: Falsification, reproduction, or alteration. 65.20 Section...reports, and records: Falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2011-01-01

389

14 CFR 63.20 - Applications, certificates, logbooks, reports, and records; falsification, reproduction, or...  

Code of Federal Regulations, 2010 CFR

...reports, and records; falsification, reproduction, or alteration. 63.20 Section...reports, and records; falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2010-01-01

390

14 CFR 65.20 - Applications, certificates, logbooks, reports, and records: Falsification, reproduction, or...  

Code of Federal Regulations, 2012 CFR

...reports, and records: Falsification, reproduction, or alteration. 65.20 Section...reports, and records: Falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2012-01-01

391

14 CFR 63.20 - Applications, certificates, logbooks, reports, and records; falsification, reproduction, or...  

Code of Federal Regulations, 2012 CFR

...reports, and records; falsification, reproduction, or alteration. 63.20 Section...reports, and records; falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2012-01-01

392

14 CFR 65.20 - Applications, certificates, logbooks, reports, and records: Falsification, reproduction, or...  

Code of Federal Regulations, 2014 CFR

...reports, and records: Falsification, reproduction, or alteration. 65.20 Section...reports, and records: Falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2014-01-01

393

14 CFR 63.20 - Applications, certificates, logbooks, reports, and records; falsification, reproduction, or...  

Code of Federal Regulations, 2013 CFR

...reports, and records; falsification, reproduction, or alteration. 63.20 Section...reports, and records; falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2013-01-01

394

14 CFR 63.20 - Applications, certificates, logbooks, reports, and records; falsification, reproduction, or...  

Code of Federal Regulations, 2011 CFR

...reports, and records; falsification, reproduction, or alteration. 63.20 Section...reports, and records; falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2011-01-01

395

14 CFR 65.20 - Applications, certificates, logbooks, reports, and records: Falsification, reproduction, or...  

Code of Federal Regulations, 2013 CFR

...reports, and records: Falsification, reproduction, or alteration. 65.20 Section...reports, and records: Falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2013-01-01

396

14 CFR 65.20 - Applications, certificates, logbooks, reports, and records: Falsification, reproduction, or...  

Code of Federal Regulations, 2010 CFR

...reports, and records: Falsification, reproduction, or alteration. 65.20 Section...reports, and records: Falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2010-01-01

397

14 CFR 63.20 - Applications, certificates, logbooks, reports, and records; falsification, reproduction, or...  

Code of Federal Regulations, 2014 CFR

...reports, and records; falsification, reproduction, or alteration. 63.20 Section...reports, and records; falsification, reproduction, or alteration. (a) No person...rating under this part; (3) Any reproduction, for fraudulent purpose, of any...

2014-01-01

398

High Efficiency Power Combining of Ka-Band TWTs for High Data Rate Communications  

NASA Technical Reports Server (NTRS)

Future NASA deep space exploration missions are expected in some cases to require telecommunication systems capable of operating at very high data rates (potentially 1 Gbps or more) for the transmission back to Earth of large volumes of scientific data, which means high frequency transmitters with large bandwidth. Among the Ka band frequencies of interest are the present 500 MHz Deep Space Network (DSN) band of 31.8 to 32.3 GHz and a broader band at 37-38 GHz allocated for space science [1]. The large distances and use of practical antenna sizes dictate the need for high transmitter power of up to 1 kW or more. High electrical efficiency is also a requirement. The approach investigated by NASA GRC is a novel wave guide power combiner architecture based on a hybrid magic-T junction for combining the power output from multiple TWTs [1,2]. This architecture was successfully demonstrated and is capable of both high efficiency (90-95%, depending on frequency) and high data rate transmission (up to 622 Mbps) in a two-way power combiner circuit for two different pairs of Ka band TWTs at two different frequency bands. One pair of TWTs, tested over a frequency range of 29.1 to 29.6 GHz, consisted of two 110-115W TWTs previously used in uplink data transmission evaluation terminals in the NASA Advanced Communications Technology Satellite (ACTS) program [1,2]. The second pair was two 100W TWTs (Boeing 999H) designed for high efficiency operation (greater than 55%) over the DSN frequency band of 31.8 to 32.3 GHz [3]. The presentation will provide a qualitative description of the wave guide circuit, results for power combining and data transmission measurements, and results of computer modeling of the magic-T and alternative hybrid junctions for improvements in efficiency and power handling capability. The power combiner results presented here are relevant not only to NASA deep space exploration missions, but also to other U.S. Government agency programs.

Wintucky, E. G.; Simons, R. N.; Vaden, K. R.; Lesny, G. G.; Glass, J. L.

2006-01-01

399

Reproductive System  

Microsoft Academic Search

\\u000a Reproduction differs from other physiological functions in the sense that it is not essential for survival of an individual,\\u000a only for that of the species. However, the prevalence of infertility is on the rise, and it seriously affects the quality\\u000a of life of the couples affected. Since both contraception and infertility problems concern young, otherwise healthy individuals,\\u000a the possibilities to

M. Poutanen; F.-P. Zhang; S. Rulli; S. Mäkelä; P. Sipilä; J. Toppari; I. Huhtaniemi

400

Do Ubiquitous Laptop Initiatives Decrease the High School Dropout Rate?  

ERIC Educational Resources Information Center

In 2007, Mooresville Graded School District developed a strategic plan to infuse twenty-first-century learning skills into the schools by providing staff and students in grades four through twelve with a laptop computer. In late fall of 2007, Mooresville High School deployed laptops to all certified staff and to the entire student body in the…

Basham, Misty Dawn

2012-01-01

401

A tensile impact apparatus for characterization of fibrous composites at high strain rates  

Microsoft Academic Search

A high rate tensile testing apparatus called “flying wedge” for testing fibrous composites at strain rates up to 103s?1 has been described. R2000 glass\\/epoxy composite has been tested at a very low strain rate of 10?3s?1 using the universal Instron tensile testing machine, and at high strain rates up to nearly 850s?1 using flying wedge. The results show significant increase

G. H. Majzoobi; F. Fereshteh Saniee; M. Bahrami

2005-01-01

402

High-strain-rate response of fiber-reinforced composite materials  

Microsoft Academic Search

The high strain-rate response and failure characteristics of several fiber-reinforced epoxy composites at high shear-strain rates were investigated. A modified split Hopkinson pressure bar was used for obtaining shear strain-rate response at rates between 8000 sec\\/sup \\/minus\\/1\\/ and 20,000 sec\\/sup \\/minus\\/1\\/. To determine the effects of fiber type and orientation, resin type, and temperature, tests were conducted at room temperature

1987-01-01

403

Mechanical analysis of woven composites at high strain rates and its application to predicting impact behavior  

Microsoft Academic Search

The deformation behavior of woven composites at high strain rates was analyzed using a constitutive equation developed to\\u000a describe the nonlinear, anisotropic\\/asymmetric and rate-dependent mechanical behavior of woven composites. The rate-dependent\\u000a nonlinear behavior of woven composites was characterized at high strain rates (1 s?1 to 100 s?1) using a tensile testing method first proposed in this research. The material properties

Hansun Ryou; Kwansoo Chung; Ji-Ho Lim

2008-01-01

404

Ctenophore population recruits entirely through larval reproduction in the central Baltic Sea.  

PubMed

The comb jelly Mertensia ovum, widely distributed in Arctic regions, has recently been discovered in the northern Baltic Sea. We show that M. ovum also exists in the central Baltic but that the population consists solely of small-sized larvae (less than 1.6 mm). Despite the absence of adults, eggs were abundant. Experiments revealed that the larvae were reproductively active. Egg production and anticipated mortality rates suggest a self-sustaining population. This is the first account of a ctenophore population entirely recruiting through larval reproduction (paedogenesis). We hypothesize that early reproduction is favoured over growth to compensate for high predation pressure. PMID:22535640

Jaspers, Cornelia; Haraldsson, Matilda; Bolte, Sören; Reusch, Thorsten B H; Thygesen, Uffe H; Kiørboe, Thomas

2012-10-23

405

High-Energy-Rate Processing of Materials Using Explosives  

NASA Astrophysics Data System (ADS)

The overall field of application of explosives substances for material processing and synthesis include: Cladding/welding of dissimilar materials; the compaction/consolidation of nanocrystalline, super-hard, high-Tc superconducting composites, metastable highly-alloyed or amorphous powdered materials; the forming of small-series of very special shape and/or very special materials plates; the cutting of metal and/or concrete structures and the synthesis of nanocrystalline, ultra-dispersed, spherical shaped, single component or multicomponent (binary and/or ternary) metal oxide particles. The very special characteristic features of this technique makes it, sometimes, the only route available to achieve singular results and a promising widespread use can be envisaged for it in a near future. Pretending to contribute for that widespread use, this paper depicted the particular cases of the explosive welding and consolidation, presenting examples of the research activity developed recently at the Department of Mechanical Engineering of the University of Coimbra.

Ribeiro, J.; Mendes, R.; Farinha, R.; Plaksin, I.; Campos, J.; Gois, J.

2009-06-01

406

Photoconductivity of ZnSe crystals under high excitation rates  

NASA Astrophysics Data System (ADS)

The generation-recombination processes in high-resistivity, undoped ZnSe single crystals as well as in ZnSe:Mg and ZnSe:Cu crystals were studied on the basis of an investigation of the photoconductivity kinetics on excitation with nanosecond laser pulses of an under-bandgap photon energy. The parameters of the recombination centres are estimated. It was established that the laser-stimulated increase in the steady-state photoconductivity of undoped ZnSe crystals with a low accidental impurity concentration was mainly due to formation of the slow recombination centres. The effect of accumulation of laser-induced point defects and its role in the observed photosensitization of highly pure ZnSe single crystals are discussed. The present results can be used in the design and analysis of various optoelectronic and optical devices using this compound.

Gnatyuk, V. A.

2000-06-01

407

Facile synthesized nanorod structured vanadium pentoxide for high-rate lithium batteries  

E-print Network

Facile synthesized nanorod structured vanadium pentoxide for high-rate lithium batteries Anqiang cathode material for high-rate lithium battery applications. 1. Introduction Lithium ion batteries have. With increasing demands for rechargeable lithium ion batteries, especially for large-scale and high

Cao, Guozhong

408

High School Principals' Rating of Success in Implementation of 21st Century Skills  

ERIC Educational Resources Information Center

The purpose of this quantitative study was to investigate how Rhode Island high school principals rate success in implementing 21st century skills in their schools. Secondly, this study investigated how high school principals rate the influence of implementing of 21st century skills in curriculum and instruction in their schools. The high…

Sam, Sonn

2011-01-01

409

The next generation high data rate VCSEL development at SEDU  

NASA Astrophysics Data System (ADS)

In May of 2012, Emcore's VCSEL FAB and VCSEL based transceiver business joined Sumitomo Electric Device Innovations USA (SEDU). After this change of ownership, our high speed VCSEL development effort continues. In this paper, we will report the progress we made in the past year in our 25Gbps to 28Gbps VCSEL. This next generation device is targeted for EDR, 32GFC as well as other optical interconnect applications.

Xie, Chuan; Li, Neinyi; Huang, Shenghong; Liu, Chiyu; Wang, Li; Jackson, Kenneth P.

2013-03-01

410

Voltage Breakdown Mechanisms in High Voltage Rated, Surface Mount MLCCs  

Microsoft Academic Search

Multilayer ceramic capacitors (MLCCs) exposed to high voltages, around 1000VDC in air, are prone to both surface-arc- over and internal breakdown. In either event failures will result at the instance of surface-arc-over as the circuit is de- stabilized which may cause damage to surrounding components even if the capacitor remains temporarily functional. The performance of HVArc GuardTM X7R capacitors, that

J. Bultitude; P. Gormally; J. Rogers; J. Jiang

411

High rep rate high performance plasma focus as a powerful radiation source  

SciTech Connect

Basic operational characteristics of the plasma focus are considered from design perspectives to develop powerful radiation sources. Using these ideas the authors have developed two compact plasma focus (CPF) devices operating in neon with high performance and high repetition rate capacity for use as an intense soft X-ray (SXR) source for microelectronics lithography. The NX1 is a four-module system with a peak current of 320 kA when the capacitor bank (7.8 {micro}F {times} 4) is charged to 14 kV. It produces 100 J of SXR per shot (4% wall plug efficiency) giving at 3 Hz, 300 W of average SXR power into 4{pi}. The NX2 is also a four-module system. Each module uses a rail gap switching 12 capacitors each with a capacity of 0.6 {micro}F. The NX2 operates with peak currents of 400 kA at 11.5 kV into water-cooled electrodes at repetition rates up to 16 Hz to produce 300 W SXR in burst durations of several minutes. SXR lithographs are taken from both machines to demonstrate that sufficient SXR lithographs are taken from both machines to demonstrate that sufficient SXR flux is generated for an exposure with only 300 shots. In addition, flash electron lithographs are also obtained requiring only ten shots per exposure. Such high performance compact machines may be improved to yield over 1 kW of SXR, enabling sufficient exposure throughput to be of interest to the wafer industry. In deuterium the neutron yield could be over 10{sup 10} neutrons per second over prolonged bursts of minutes.

Lee, S.; Lee, P.; Zhang, G.; Feng, X.; Liu, M.; Serban, A.; Wong, T.K.S. [Nanyang Technological Univ. (Singapore); Gribkov, V.A. [Russian Academy of Sciences, Moscow (Russian Federation)

1998-08-01

412

High-rate synthetic aperture communications in shallow water.  

PubMed

Time reversal communication exploits spatial diversity to achieve spatial and temporal focusing in complex ocean environments. Spatial diversity can be provided easily by a vertical array in a waveguide. Alternatively, spatial diversity can be obtained from a virtual horizontal array generated by two elements, a transmitter and a receiver, due to relative motion between them, referred to as a synthetic aperture. This paper presents coherent synthetic aperture communication results from at-sea experiments conducted in two different frequency bands: (1) 2-4 kHz and (2) 8-20 kHz. Case (1) employs binary-phase shift-keying modulation, while case (2) involves up to eight-phase shift keying modulation with a data rate of 30 kbits/s divided by the number of transmissions (diversity) to be accumulated. The receiver utilizes time reversal diversity combining followed by a single channel equalizer, with frequent channel updates to accommodate the time-varying channel due to coupling of space and time in the presence of motion. Two to five consecutive transmissions from a source moving at 4 kts over 3-6 km range in shallow water are combined successfully after Doppler compensation, confirming the feasibility of coherent synthetic aperture communications using time reversal. PMID:20000919

Song, H C; Hodgkiss, W S; Kuperman, W A; Akal, T; Stevenson, M

2009-12-01

413

Deformation and fracture of unidirectional GFRP composites at high strain rate tension  

Microsoft Academic Search

This work deals with experimental investigation of the high strain rate behaviour of unidirectional (UD) glass fibre-reinforced (GFRP) composite materials. The related experiments were performed with a high rate test machine to determine the mechanical properties of UD E-glass\\/epoxy composites. The specimens were tested separately under quasi-static and high-speed conditions with loading rates of up to 20 m\\/s. All specimens

G. Makarov; W. Wang; R. A. Shenoi

414

Global warming and reproductive health.  

PubMed

The largest absolute numbers of maternal deaths occur among the 40-50 million women who deliver annually without a skilled birth attendant. Most of these deaths occur in countries with a total fertility rate of greater than 4. The combination of global warming and rapid population growth in the Sahel and parts of the Middle East poses a serious threat to reproductive health and to food security. Poverty, lack of resources, and rapid population growth make it unlikely that most women in these countries will have access to skilled birth attendants or emergency obstetric care in the foreseeable future. Three strategies can be implemented to improve women's health and reproductive rights in high-fertility, low-resource settings: (1) make family planning accessible and remove non-evidenced-based barriers to contraception; (2) scale up community distribution of misoprostol for prevention of postpartum hemorrhage and, where it is legal, for medical abortion; and (3) eliminate child marriage and invest in girls and young women, thereby reducing early childbearing. PMID:22883918

Potts, Malcolm; Henderson, Courtney E

2012-10-01

415

High-rate thermophilic anaerobic digestion of agricultural wastes  

SciTech Connect

There are many settlements in Israel known as Kibbutzim which provide an interface between the agricultural sector, the industrial sector, and a community with a high per capita energy consumption. Hence, these settlements provide an ideal site for the operation of anaerobic digestion for the treatment of agricultural wastes and the utilization of the resultant energy supply. While the substrate initially used in this study was dairy-cow manure collected from the concrete floors of corrals, the contribution of other organic wastes such as straw, cotton plants, and chicken manure was also evaluated. It has been reported in the literature that some materials when added to the anaerobic digestion process lead to enhancement of gas production and improvement in digester operation. Hence, the effects on the performance of highly loaded thermophilic digesters of several materials such as activated carbon, cobalt salts, and calcium hydroxide were examined in this study. Pilot-plant units of 1000 and 10,000 liter were an intergral part of the study program. These units were used to verify results obtained with the 4-liter laboratory units. An energy survey was conducted on the larger units. These units were also used to supply large quantities of gas for utilization experiments and to provide the large quantities of digested sludge required for animal-feeding trials and fertilizer experiments. The pilot-plant units also afforded the opportunity to solve technical problems which would arise in full-size units.

Shelef, G.; Kimchie, S.; Grynberg, H.

1980-01-01

416

Effect of human chorionic gonadotropin on luteal function and reproductive performance of high-producing lactating Holstein dairy cows.  

PubMed

The objectives were to evaluate effects of human chorionic gonadotropin (hCG) (3,300 IU i.m.) administered on d 5 after AI on CL number, plasma progesterone concentration, conception rate, and pregnancy loss in high-producing dairy cows. Following the synchronization of estrus and AI, 406 cows were injected with either hCG or saline on d 5 after AI in a randomized complete block design. Blood sampling and ovarian ultrasonography were conducted once between d 11 and 16 after AI. Pregnancy diagnoses were performed on d 28 by ultrasonography and on d 45 and 90 after AI by rectal palpation. Treatment with hCG on d 5 resulted in 86.2% of the cows with more than one CL compared with 23.2% in controls. Plasma progesterone concentrations were increased by 5.0 ng/mL in hCG-treated cows. The presence of more than one CL increased progesterone concentration in hCG-treated cows but not in controls. Conception rates were higher for hCG-treated cows on d 28 (45.8 > 38.7%), 45 (40.4 > 36.3%), and 90 (38.4 > 31.9%) after AI. Treatment with hCG improved conception rate in cows losing body condition between AI and d 28 after Al. Pregnancy losses were similar between treatment groups. Treatment with hCG on d 5 after AI induces accessory CL, enhances plasma progesterone concentration, and improves conception rate of high-producing dairy cows. PMID:11768118

Santos, J E; Thatcher, W W; Pool, L; Overton, M W

2001-11-01

417

Learning rate and temperament in a high predation risk environment.  

PubMed

Living in challenging environments can influence the behavior of animals in a number of ways. For instance, populations of prey fish that experience frequent, nonlethal interactions with predators have a high proportion of individuals that express greater reaction to risk and increased activity and exploration-collectively known as temperament traits. Temperament traits are often correlated, such that individuals that are risk-prone also tend to be active and explore more. Spatial learning, which requires the integration of many sensory cues, has also been shown to vary in fish exposed to different levels of predation threat. Fish from areas of low predation risk learn to solve spatial tasks faster than fish from high predation areas. However, it is not yet known whether simpler forms of learning, such as learning associations between two events, are similarly influenced. Simple forms of associative learning are likely to be affected by temperament because a willingness to approach and explore novel situations could provide animals with a learning advantage. However, it is possible that routine-forming and inflexible traits associated with risk-prone and increased exploratory behavior may act in the opposite way and make risk-prone individuals poorer at learning associations. To investigate this, we measured temperament in Panamanian bishop fish (Brachyrhaphis episcopi) sampled from a site known to contain many predators. The B. episcopi were then tested with an associative learning task. Within this population, fish that explored more were faster at learning a cue that predicted access to food, indicating a link between temperament and basic learning abilities. PMID:25270336

DePasquale, C; Wagner, T; Archard, G A; Ferguson, B; Braithwaite, V A

2014-11-01

418

Application of high-speed photography to the study of high-strain-rate materials testing  

NASA Astrophysics Data System (ADS)

There is a growing interest in material behaviour at strain rates greater than 104sec1, for instance in the design of aero-engine turbine blades. It is necessary therefore, to develop material testing techniques that give well-defined information on mechanical behaviour in this very high strain-rate regime. A number of techniques are available, including the expanding ring test1, a miniaturised compression Hopkinson bar technique using direct impact and the double-notch shear test3 which has been described by Nicholas4 as "one of the most promising for future studies in dynamic plasticity". However, although it is believed to be a good test for determining the flow stress at shear strain rates of 104sec and above, the design of specimen used makes an accurate determination of strain extremely difficult while, in the later stages of the test the deformation mode involves rotation as well as shear. If this technique is to be used, therefore, it is necessary to examine in detail the progressive deformation and state of stress within the specimen during the impact process. An attempt can then be made to assess how far the data obtained is a reliable measure of the specimen material response and the test can be calibrated. An extensive three stage analysis has been undertaken. In the first stage, reported in a previous paper5, the initial elastic behaviour was studied. Dynamic photoelastic experiments were used to support linear elastic numerical results derived by the finite element method. Good qualitative agreement was obtained between the photoelastic experiment and the numerical model and the principal source of error in the elastic region of the double-notch shear test was identified as the assumption that all deformation of the specimen is concentrated in the two shear zones. For the epoxy (photoelastic) specimen a calibration factor of 5.3 was determined. This factor represents the ratio between the defined (nominal) gauge length and the effective gauge length. The second stage of the analysis of the double-notch shear (DNS) specimen is described in this paper. This consists of the use of ultra-high speed photography to provide information on the plastic deformation behaviour of the specimen. Two different high speed cine cameras were used for this work, a Hadland "Imacon" 792 electronic image converter camera and a Cordin 377 rotating mirror-drum optical camera. Implementation of the two cameras and photographic results are briefly compared and contrasted here. Stage three of this work consists of an advanced numerical analysis of the elasto-plastic, strain rate dependent behaviour of the DNS specimen. The principle intention of the authors was to use the physical data collected from high speed photographs for correlation with this work. Full details of the numerical work are presented elsewhere6 but some salient results will be given here for completeness.

Ruiz, D.; Harding, John; Noble, J. P.; Hillsdon, Graham K.

1991-04-01

419

Dynamic deformation behavior of a high reinforcement content TiB 2\\/Al composite at high strain rates  

Microsoft Academic Search

Dynamic compressive properties of a 60vol.% TiB2\\/Al composite fabricated by squeeze casting method were measured using split Hopkinson pressure bar. The 60vol.% TiB2\\/Al composite showed significant strain-rate sensitivity compared with the rate insensitive aluminum alloy matrix. The flow stress and the strain-rate sensitivity both showed rise\\/fall tendency at high strain rates. Moreover, a large plastic strain as 7.8% was obtained

Dezhi Zhu; Gaohui Wu; Guoqin Chen; Qiang Zhang

2008-01-01

420

Reproductive acclimation to increased water temperature in a tropical reef fish.  

PubMed

Understanding the capacity of organisms to cope with projected global warming through acclimation and adaptation is critical to predicting their likely future persistence. While recent research has shown that developmental acclimation of metabolic attributes to ocean warming is possible, our understanding of the plasticity of key fitness-associated traits, such as reproductive performance, is lacking. We show that while the reproductive ability of a tropical reef fish is highly sensitive to increases in water temperature, reproductive capacity at +1.5°C above present-day was improved to match fish maintained at present-day temperatures when fish complete their development at the higher temperature. However, reproductive acclimation was not observed in fish reared at +3.0°C warmer than present-day, suggesting limitations to the acclimation possible within one generation. Surprisingly, the improvements seen in reproduction were not predicted by the oxygen- and capacity-limited thermal tolerance hypothesis. Specifically, pairs reared at +1.5°C, which showed the greatest capacity for reproductive acclimation, exhibited no acclimation of metabolic attributes. Conversely, pairs reared at +3.0°C, which exhibited acclimation in resting metabolic rate, demonstrated little capacity for reproductive acclimation. Our study suggests that understanding the acclimation capacity of reproductive performance will be critically important to predicting the impacts of climate change on biological systems. PMID:24823490

Donelson, Jennifer M; McCormick, Mark I; Booth, David J; Munday, Philip L

2014-01-01

421

Female reproductive disorders: the roles of endocrine-disrupting compounds and developmental timing  

PubMed Central

Objective To evaluate the possible role of endocrine-disrupting compounds (EDCs) on female reproductive disorders emphasizing developmental plasticity and the complexity of endocrine-dependent ontogeny of reproductive organs. Declining conception rates and the high incidence of female reproductive disruptions warrant evaluation of the impact of EDCs on female reproductive health. Design Publications related to the contribution of EDCs to disorders of the ovary (aneuploidy, polycystic ovary syndrome, and altered cyclicity), uterus (endometriosis, uterine fibroids, fetal growth restriction, and pregnancy loss), breast (breast cancer, reduced duration of lactation), and pubertal timing were identified, reviewed, and summarized at a workshop. Conclusion(s) The data reviewed illustrate that EDCs contribute to numerous human female reproductive disorders and emphasize the sensitivity of early life-stage exposures. Many research gaps are identified that limit full understanding of the contribution of EDCs to female reproductive problems. Moreover, there is an urgent need to reduce the incidence of these reproductive disorders, which can be addressed by correlative studies on early life exposure and adult reproductive dysfunction together with tools to assess the specific exposures and methods to block their effects. This review of the EDC literature as it relates to female health provides an important platform on which women’s health can be improved. PMID:18929049

Crain, D. Andrew; Janssen, Sarah J.; Edwards, Thea M.; Heindel, Jerrold; Ho, Shuk-mei; Hunt, Patricia; Iguchi, Taisen; Juul, Anders; McLachlan, John A.; Schwartz, Jackie; Skakkebaek, Niels; Soto, Ana M.; Swan, Shanna; Walker, Cheryl; Woodruff, Teresa K.; Woodruff, Tracey J.; Giudice, Linda C.; Guillette, Louis J.

2014-01-01

422

Modeling of cylindrical alkaline cells; V: High discharge rates  

SciTech Connect

A one-dimensional mathematical model of a AA size Zn-MnO{sub 2} alkaline cell is presented to describe nonisothermal, high constant current discharge conditions. The model accounts for the variation of the overpotential, current density, porosity, volume, average velocity, hydroxyl ion concentration, and zincate ion concentration throughout a complete cell, including the anode, cathode, and separator regions. This model is the first to examine the importance of the zincate ion concentration. Three variations of the model are presented: (1) the zincate ion is restricted to the anode region, (2) the zincate ion is unconfined in the cell, but can precipitate as ZnO in the anode, and (3) the zincate is unconfined in the cell but can precipitate in both the anode and separator. Experimental data are best represented by model (3). Pore plugging, particularly in the separator, has been found to be an important factor limiting cell performance. Additionally, the sensitivity of several parameters on the cell performance is evaluated.

Podlaha, E.J.; Cheh, H.Y. [Columbia Univ., New York, NY (United States). Dept. of Chemical Engineering and Applied Chemistry

1994-01-01

423

Apparent rates of increase for two feral horse herds  

SciTech Connect

Rates of increase for 2 Oregon feral horse (Equus caballus) herds were estimated from direct aerial counts to be about 20% per year. These rates can be achieved only if survival rates are high, and reproduction exceeds that normally expected from horses. A population dynamics model suggests adult survival to be the key parameter in determining rates of increase, and there is some direct evidence of high adult survival rates. Management implications are discussed.

Eberhardt, L.L. (Battelle Memorial Inst., Richland, WA); Majorowicz, A.K.; Wilcox, J.A.

1982-01-01

424

Preliminary Findings on Quantitative Measures for Distinguishing Highly Rated Information-Centric Web Pages  

Microsoft Academic Search

We present preliminary findings of a quantitative analysis of several attributes of Web page layout and composition and their relation to usability. We compared Web sites that have been favorably rated by experts with those that have not been rated, and found that 6 out of 12 measured attributes were significantly associated with highly rated sites. We also found 2

Melody Y. Ivory; Rashmi R. Sinha; Marti A. Hearst

425

Molecular dynamics study on superheating of Pd at high heating rates  

Microsoft Academic Search

Molecular dynamics simulations are employed here to study the melting and superheating behaviors of bulk Palladium at high heating rates. Quantum Sutton-Chen many body potential is used for these simulations. Being heated, the superheating and melting behavior is found to be strongly affected by the heating rate, and heating rate induced randomization during non-equilibrium heating processes is found to be

Xin Liu; Changgong Meng; Changhou Liu

2006-01-01

426

Dependence of Growing High-Quality Gem Diamonds on Growth Rates by Temperature Gradient Method  

NASA Astrophysics Data System (ADS)

Using the temperature gradient method under high pressure and high temperature, we investigate the dependence of growing high-quality gem diamond crystals on the growth rates. It is found that the lower the growth rate of gem diamond crystals, the larger the temperature range of growing high-quality gem diamond crystals, and the easier the control of temperature. In particular, when growing gem diamonds under a very-low growth rate, the temperature range of growing high-quality gem diamonds can extend from a low-temperature pure {100} growth region to {100} +{111} growth regions, and finally to a high-temperature only-{111}-growth region. When growing gem diamonds under a high growth rate, some metal inclusions in the growing diamonds always exist near the seeds, no matter whether the growth temperature is high or low. This result is not in agreement with the result of Sumitomo Electric Corporation in Japan.

Zang, Chuan-Yi; Jia, Xiao-Peng; Ren, Guo-Zhong; Wang, Xian-Cheng

2004-08-01

427

Low-dose-rate or high-dose-rate brachytherapy in treatment of prostate cancer – between options  

PubMed Central

Purpose Permanent low-dose-rate (LDR-BT) and temporary high-dose-rate (HDR-BT) brachytherapy are competitive techniques for clinically localized prostate radiotherapy. Although a randomized trial will likely never to be conducted comparing these two forms of brachytherapy, a comparative analysis proves useful in understanding some of their intrinsic differences, several of which could be exploited to improve outcomes. The aim of this paper is to look for possible similarities and differences between both brachytherapy modalities. Indications and contraindications for monotherapy and for brachytherapy as a boost to external beam radiation therapy (EBRT) are presented. It is suggested that each of these techniques has attributes that advocates for one or the other. First, they represent the extreme ends of the spectrum with respect to dose rate and fractionation, and therefore have inherently different radiobiological properties. Low-dose-rate brachytherapy has the great advantage of being practically a one-time procedure, and enjoys a long-term follow-up database supporting its excellent outcomes and low morbidity. Low-dose-rate brachytherapy has been a gold standard for prostate brachytherapy in low risk patients since many years. On the other hand, HDR is a fairly invasive procedure requiring several sessions associated with a brief hospital stay. Although lacking in significant long-term data, it possesses the technical advantage of control over its postimplant dosimetry (by modulating the source dwell time and position), which is absent in LDR brachytherapy. This important difference in dosimetric control allows HDR doses to be escalated safely, a flexibility that does not exist for LDR brachytherapy. Conclusions Radiobiological models support the current clinical evidence for equivalent outcomes in localized prostate cancer with either LDR or HDR brachytherapy, using current dose regimens. At present, all available clinical data regarding these two techniques suggests that they are equally effective, stage for stage, in providing high tumor control rates. PMID:23634153

2013-01-01

428

A novel VLSI processor for high-rate, high resolution spectroscopy  

NASA Astrophysics Data System (ADS)

A novel time-variant VLSI shaper amplifier, suitable for multi-anode Silicon Drift Detectors or other multi-element solid-state X-ray detection systems, is proposed. The new read-out scheme has been conceived for demanding applications with synchrotron light sources, such as X-ray holography or EXAFS, where both high count-rates and high-energy resolutions are required. The circuit is of the linear time-variant class, accepts randomly distributed events and features: a finite-width (1-10 ?s) quasi-optimal weight function, an ultra-low-level energy discrimination (˜150 eV), and a full compatibility for monolithic integration in CMOS technology. Its impulse response has a staircase-like shape, but the weight function (which is in general different from the impulse response in time-variant systems) is quasi trapezoidal. The operation principles of the new scheme as well as the first experimental results obtained with a prototype of the circuit are presented and discussed in the work.

Pullia, A.; Fiorini, C.; Gatti, E.; Longoni, A.; Buttler, W.

2000-01-01

429

Weak Line Quasars at High Redshift: Extremely High Accretion Rates or Anemic Broad-line Regions?  

NASA Astrophysics Data System (ADS)

We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z = 3.55 and SDSS J123743.08+630144.9 at z = 3.49. In both sources, we detect an unusually weak broad H? line and place tight upper limits on the strengths of their [O III] lines. Virial, H?-based black hole mass determinations indicate normalized accretion rates of L/L Edd=0.4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts. We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of ? = 1.91+0.24 -0.22, which supports the virial L/L Edd determination in this source. Our results suggest that the weakness of the broad emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad emission line region properties.

Shemmer, Ohad; Trakhtenbrot, Benny; Anderson, Scott F.; Brandt, W. N.; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Lira, Paulina; Netzer, Hagai; Plotkin, Richard M.; Richards, Gordon T.; Schneider, Donald P.; Strauss, Michael A.

2010-10-01

430

Metabolic rate and gross efficiency at high work rates in world class and national level sprint skiers.  

PubMed

The present study investigated metabolic rate (MR) and gross efficiency (GE) at moderate and high work rates, and the relationships to gross kinematics and physical characteristics in elite cross-country skiers. Eight world class (WC) and eight national level (NL) male sprint cross-country skiers performed three 5-min stages using the skating G3 technique, whilst roller skiing on a treadmill. GE was calculated by dividing work rate by MR. Work rate was calculated as the sum of power against gravity and frictional rolling forces. MR was calculated using gas exchange and blood lactate values. Gross kinematics, i.e. cycle length (CL) and cycle rate (CR) were measured by video analysis. Furthermore, the skiers were tested for time to exhaustion (TTE), peak oxygen uptake (VO(2peak)), and maximal speed (V(max)) on the treadmill, and maximal strength in the laboratory. Individual performance level in sprint skating was determined by FIS points. WC skiers did not differ in aerobic MR, but showed lower anaerobic MR and higher GE than NL skiers at a given speed (all P < 0.05). Moreover, WC skiers skated with longer CL and had higher V(max) and TTE (all P < 0.05). In conclusion, the present study shows that WC skiers are more efficient than NL skiers, and it is proposed that this might be due to a better technique and to technique-specific power. PMID:20151149

Sandbakk, Øyvind; Holmberg, Hans-Christer; Leirdal, Stig; Ettema, Gertjan

2010-06-01

431

Spectroscopic characterization of high-energy and high fluence rate photon beams  

NASA Astrophysics Data System (ADS)

High-energy, high fluence rate photon sources are used in radiation oncology for the treatment of a variety of disease sites. Common dosimetry methods for characterizing these sources use energy-integrating devices; however, the most descriptive characterization of these sources are performed with devices that preserve the energy-specific information in the source output. This work used Monte-Carlo- (MC-) and measurement-based spectroscopic methods to characterize two therapeutic-level megavoltage photon sources. MC simulations were performed using the MCNP5 transport code and measurements were performed with a Compton-scattering (CS) technique. Because MC was used extensively in this work, some general MCNP5 investigations were performed to benchmark the techniques used. Limitations in the advanced variance reduction techniques, Doppler-broadening model, and use of phase space files were investigated. Based on the results of these investigations, recommendations were made for using each technique. The validity of the CS technique for use with megavoltage systems was demonstrated using MC simulations of a 6 MV linear accelerator field and measurements of a high dose rate 192Ir source. Following these initial demonstrations, the spectrum of a 60Co teletherapy unit was characterized. Simulations were performed to determine the spectrum's sensitivity to the source model. Multiple measurements were completed using a reverse-electrode germanium (REGe) detector with the CS spectrometry technique. The CS spectra were corrected for detector response and the CS geometry using a novel detector response function that was calculated using MCNP5. The detector response was unfolded using the Gold deconvolution method. Comparisons of the simulated and measured spectra showed agreement in terms of the peak positions, mean spectrum energy, and relative fluences under specific portions of the spectra. The spectrum of a 6 MV photon field from a Varian Clinac iX linear accelerator was also characterized. Simulations were performed to determine the spectrum's sensitivity to changes in the primary electron source parameters of mean energy, spot size, and divergence. In addition, measurements were performed using the CS technique with the REGe detector. These measurements demonstrated that the linac spectrum was detectable above background, and the CS signal was dependent on field size.

Bartol, Laura J.

432

MEET OUR PHYSICIANS Reproductive  

E-print Network

MEET OUR PHYSICIANS Reproductive Endocrinology & Infertility 866.600.CARE hospital.uillinois.edu Reproductive Endocrinology & Infertility at the UI Health System about The Reproductive Endocrinology & Infertility faculty at the University of Illinois Hospital & Health Sciences System provide cutting

Alford, Simon

433

Normal Female Reproductive Anatomy  

MedlinePLUS

... Search Quick Search Image Details Reproductive System, Female, Anatomy View/Download: Small: 720x756 View Download Add to My Pictures Title: Reproductive System, Female, Anatomy Description: Anatomy of the female reproductive system; drawing ...

434

Female Reproductive System  

MedlinePLUS

About Human Reproduction All living things reproduce. Reproduction — the process by which organisms make more organisms like themselves — is ... essential to keeping an individual alive. In the human reproductive process, two kinds of sex cells, or ...

435

My Reproductive Life Plan  

MedlinePLUS

... Button Information For... Media Policy Makers My Reproductive Life Plan Language: English Español (Spanish) Share Compartir Thinking ... to achieve those goals is called a reproductive life plan . There are many kinds of reproductive life ...

436

Interactions for pollinator visitation and their consequences for reproduction in a plant community  

NASA Astrophysics Data System (ADS)

Competition and facilitation in species interactions attract much attention in ecology, but their relative importance has seldom been evaluated in a community context. We assessed competitive and facilitative interactions for pollinator visitation among co-flowering species in a plant community, investigated the subsequent consequences for plant reproduction, and investigated whether effects could be trait-based. We removed the flowers of two species attractive to pollinators, in two separate experiments and assessed the effects on pollinator visitation rates and components of reproductive success in 11 co-flowering focal herb species. Overall, most focal species appear not to interact with the removal species with respect to pollinator visitation and subsequent reproduction (neutral interactions). Three focal species in the community had significantly higher reproductive responses (fruit production and seed weight) in the presence of the attractive removal species (facilitative interactions), but species interaction effects were less pronounced in species' flower visitation rates. A community-wide meta-analysis demonstrated that the two experiments did not have a significant effect on either facilitation or competition, and that there was no overall correlation between effect sizes for visitation and reproduction. Based on species-specific responses, it seems likely that floral traits such as similar flower colors contribute to interspecific facilitation of pollinator visitation and, in particular, that high pollinator dependence for plant reproduction, and associated pollen limitation, may contribute to subsequent interaction effects on reproduction in the focal species.

Hegland, Stein Joar; Totland, Ørjan

2012-08-01

437

A testing technique for concrete under confinement at high rates of strain P. Forquin1,  

E-print Network

1 A testing technique for concrete under confinement at high rates of strain P. Forquin1, , F high strain-rates. The specimen is confined in a metallic ring and loaded by means of a big hard steel glued on its lateral surface allow for the measurement of the confining pressure. The spherical

438

The Effect of Selected Nonmusical Factors on Adjudicators' Ratings of High School Solo Vocal Performances  

ERIC Educational Resources Information Center

The purpose of this study was to examine the effect of differentiated performance attire and stage deportment on adjudicators' ratings of high school solo vocal performances. High school choral students (n = 153) and undergraduate (n = 97) and graduate music majors (n = 32) served as adjudicators (N = 282). Adjudicators rated recorded solo vocal…

Howard, Sandra A.

2012-01-01

439