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1

High basal metabolic rate does not elevate oxidative stress during reproduction in laboratory mice.  

PubMed

Increased oxidative stress (OS) has been suggested as a physiological cost of reproduction. However, previous studies reported ambiguous results, with some even showing a reduction of oxidative damage during reproduction. We tested whether the link between reproduction and OS is mediated by basal metabolic rate (BMR), which has been hypothesized to affect both the rate of radical oxygen species production and antioxidative capacity. We studied the effect of reproduction on OS in females of laboratory mice divergently selected for high (H-BMR) and low (L-BMR) BMR, previously shown to differ with respect to parental investment. Non-reproducing L-BMR females showed higher oxidative damage to lipids (quantified as the level of malondialdehyde in internal organ tissues) and DNA (quantified as the level of 8-oxodG in blood serum) than H-BMR females. Reproduction did not affect oxidative damage to lipids in either line; however, it reduced damage to DNA in L-BMR females. Reproduction increased catalase activity in liver (significantly stronger in L-BMR females) and decreased it in kidneys. We conclude that the effect of reproduction on OS depends on the initial variation in BMR and varies between studied internal organs and markers of OS. PMID:24436386

Brz?k, Pawe?; Ksi?zek, Aneta; O?dakowski, Lukasz; Konarzewski, Marek

2014-05-01

2

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.

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

2013-01-01

3

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

4

Ejaculate components delay reproductive senescence while elevating female reproductive rate in an insect  

PubMed Central

Increased female reproductive rates usually result in accelerated senescence. This correlation provides a link between the evolutionary conflict of the sexes and aging when ejaculate components elevate female reproductive rates at the cost of future reproduction. It is not clear whether this female cost is manifest as shorter lifespan or an earlier onset or a steeper rate of reproductive senescence. It also is unclear whether beneficial ejaculates release females from reproductive trade-offs and, if so, which senescence parameters are affected. We examined these issues in the bedbug, Cimex lectularius, a long-lived insect that shows reduced female lifespan as well as female reproductive senescence at the male-determined mating frequency. We demonstrate experimentally that, independently of the mating frequency, females receiving more ejaculate show increased reproductive rates and enter reproductive senescence later than females receiving less ejaculate. The rate of reproductive senescence did not differ between treatments, and reproductive rates did not predict mortality. The ejaculate effects were consistent in inter- and intra-population crosses, suggesting they have not evolved recently and are not caused by inbreeding. Our results suggest that ejaculate components compensate for the costs of elevated female reproductive rates in bedbugs by delaying the onset of reproductive senescence. Ejaculate components that are beneficial to polyandrous females could have arisen because male traits that protect the ejaculate have positive pleiotropic effects and/or because female counteradaptations to antagonistic male traits exceed the neutralization of those traits. That males influence female reproductive senescence has important consequences for trade-offs between reproduction and longevity and for studies of somatic senescence.

Reinhardt, Klaus; Naylor, Richard A.; Siva-Jothy, Michael T.

2009-01-01

5

Transmission rate and reproductive number of the H5N1 highly pathogenic avian influenza virus during the December 2005-July 2008 epidemic in Nigeria.  

PubMed

We quantified the between-village transmission rate, ? (the rate of transmission of H5N1 HPAI virus per effective contact), and the reproductive number, Re (the average number of outbreaks caused by one infectious village during its entire infectious period), of H5N1 highly pathogenic avian influenza (HPAI) virus in Nigeria using outbreak data collected between December 2005 and July 2008. We classified the outbreaks into two phases to assess the effectiveness of the control measures implemented. Phase 1 (December 2005-October 2006) represents the period when the Federal Government of Nigeria managed the HPAI surveillance and response measures, while Phase 2 (November 2006-July 2008) represents the time during which the Nigeria Avian Influenza Control and Human Pandemic Preparedness project (NAICP), funded by a World Bank credit of US$ 50 million, had taken over the management of most of the interventions. We used a total of 204 outbreaks from 176 villages that occurred in 78 local government areas of 25 states. The compartmental susceptible-infectious model was used as the analytical tool. Means and 95% percentile confidence intervals were obtained using bootstrapping techniques. The overall mean ? (assuming a duration of infectiousness, T, of 12 days) was 0.07/day (95% percentile confidence interval: 0.06-0.09). The first and second phases of the epidemic had comparable ? estimates of 0.06/day (0.04-0.09) and 0.08/day (0.06-0.10), respectively. The Re of the virus associated with these ? and T estimates was 0.9 (0.7-1.1); the first and second phases of the epidemic had Re of 0.84 (0.5-1.2) and 0.9 (0.6-1.2), respectively. We conclude that the intervention measures implemented in the second phase of the epidemic had comparable effects to those implemented during the first phase and that the Re of the epidemic was low, indicating that the Nigeria H5N1 HPAI epidemic was unstable. PMID:22925404

Bett, B; Henning, J; Abdu, P; Okike, I; Poole, J; Young, J; Randolph, T F; Perry, B D

2014-02-01

6

Reproductive Rates in Australian Rodents Are Related to Phylogeny  

PubMed Central

Background The native rodents of Australia are commonly divided into two groups based on the time of their colonization of the Sahulian continent, which encompasses Australia, New Guinea, and the adjacent islands. The first group, the “old endemics,” is a diverse assemblage of 34 genera that are descended from a single colonization of the continent during the Pliocene. A second group, the “new endemics,” is composed of several native Rattus species that are descended from a single colonization during the Pleistocene. Finally, a third group is composed of three non-native species of Rattus and Mus introduced into Australia by humans over the last 200 years. Previous studies have claimed that the three groups differ in their reproductive rates and that this variation in rates is associated with the unique environmental conditions across Australia. We examined these hypotheses using phylogenetically controlled methods. Methodology and Results We examined the relationship between the reproductive rates of the Australian rodents and the environmental variations across the continent, as well as the epoch of their colonization of the continent. Our results revealed no significant correlation with environmental variables but a significant association between colonization age and all the reproductive parameters examined. Discussion Based on a larger phylogeny of the subfamily Murinae, we showed that significant differences in reproductive rates among colonization groups are shared with their closest relatives outside Sahul. Therefore, the lower reproductive rates in the old endemics are more likely to be the result of phylogenetic history and conservation of traits than an adaptation to the Australian environment. In the new endemics, we found a trend of increasing reproductive rates with diversification. We suggest that the differences in reproductive rates of the old endemic rodents and the native Rattus represent alternative adaptive strategies that have allowed them to utilize similar ecological niches across Australia.

Geffen, Eli; Rowe, Kevin C.; Yom-Tov, Yoram

2011-01-01

7

High-resolution color photographic reproductions  

NASA Astrophysics Data System (ADS)

This paper will describe a fine-art reproduction process that: captures painting information with high-resolution color photographs; scans the information into a 300 megabyte digital file; performs a 3D color calibration in a dedicated hardware color-transform circuit; makes a master positive color transparency and makes a reproduction on polaroid color print film. The master transparency can be used to expose a large number of images. This combines the efficiency of instant photography with the color fidelity of digital color transforms.

McCann, John J.

1997-04-01

8

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

9

Influence of copper on the feeding rate, growth and reproduction of the golden apple snail, Pomacea canaliculata Lamarck.  

PubMed

The influence of copper on feeding rate, growth, and reproduction of Pomacea canaliculata Lamarck was evaluated. Ten days of exposure to copper of relatively high concentration (67.5 microg/L) reduced the snails' feeding rate and retarded their growth. Exposure to 20 microg/L after 36 days increased feeding rate to 28%. After 20 days of exposure at 30 microg/L, snail's growth was significant but thereafter declined. Growth of all snails including control was negligible by day 50 when snails were in the reproductive state. Copper did not affect reproduction. PMID:17999015

Peña, Silvia C; Pocsidio, Glorina N

2007-12-01

10

High Rate Digital Demodulator ASIC  

NASA Technical Reports Server (NTRS)

The architecture of High Rate (600 Mega-bits per second) Digital Demodulator (HRDD) ASIC capable of demodulating BPSK and QPSK modulated data is presented in this paper. The advantages of all-digital processing include increased flexibility and reliability with reduced reproduction costs. Conventional serial digital processing would require high processing rates necessitating a hardware implementation in other than CMOS technology such as Gallium Arsenide (GaAs) which has high cost and power requirements. It is more desirable to use CMOS technology with its lower power requirements and higher gate density. However, digital demodulation of high data rates in CMOS requires parallel algorithms to process the sampled data at a rate lower than the data rate. The parallel processing algorithms described here were developed jointly by NASA's Goddard Space Flight Center (GSFC) and the Jet Propulsion Laboratory (JPL). The resulting all-digital receiver has the capability to demodulate BPSK, QPSK, OQPSK, and DQPSK at data rates in excess of 300 Mega-bits per second (Mbps) per channel. This paper will provide an overview of the parallel architecture and features of the HRDR ASIC. In addition, this paper will provide an over-view of the implementation of the hardware architectures used to create flexibility over conventional high rate analog or hybrid receivers. This flexibility includes a wide range of data rates, modulation schemes, and operating environments. In conclusion it will be shown how this high rate digital demodulator can be used with an off-the-shelf A/D and a flexible analog front end, both of which are numerically computer controlled, to produce a very flexible, low cost high rate digital receiver.

Ghuman, Parminder; Sheikh, Salman; Koubek, Steve; Hoy, Scott; Gray, Andrew

1998-01-01

11

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.

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

2013-01-01

12

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

PubMed

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

2013-07-01

13

Influence of Copper on the Feeding Rate, Growth and Reproduction of the Golden Apple Snail, Pomacea canaliculata Lamarck  

Microsoft Academic Search

The influence of copper on feeding rate, growth, and reproduction of Pomacea canaliculata Lamarck was evaluated. Ten days of exposure to copper of relatively high concentration (67.5 ?g\\/L) reduced the snails’ feeding\\u000a rate and retarded their growth. Exposure to 20 ?g\\/L after 36 days increased feeding rate to 28%. After 20 days of exposure\\u000a at 30 ?g\\/L, snail’s growth was significant but thereafter

Silvia C. Peña; Glorina N. Pocsidio

2007-01-01

14

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

PubMed

Abstract 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

15

Low Reproductive Rate Predicts Species Sensitivity to Habitat Loss: A Meta-Analysis of Wetland Vertebrates  

PubMed Central

We tested the hypotheses that species with greater mobility and/or higher reproductive rates are less sensitive to habitat loss than species with lower mobility and/or reproductive rates by conducting a meta-analysis of wetland vertebrate responses to wetland habitat loss. We combined data from 90 studies conducted worldwide that quantified the relationship between wetland amount in a landscape and population abundance of at least one wetland species to determine if mobility (indexed as home range size and body length) and annual reproductive rate influence species responses to wetland loss. When analyzed across all taxa, animals with higher reproductive rates were less sensitive to wetland loss. Surprisingly, we did not find an effect of mobility on response to wetland loss. Overall, wetland mammals and birds were more sensitive to wetland loss than were reptiles and amphibians. Our results suggest that dispersal between habitat patches is less important than species’ reproductive rates for population persistence in fragmented landscapes. This implies that immigration and colonization rate is most strongly related to reproduction, which determines the total number of potential colonists.

Quesnelle, Pauline E.; Lindsay, Kathryn E.; Fahrig, Lenore

2014-01-01

16

Low reproductive success of leatherback turtles, Dermochelys coriacea, is due to high embryonic mortality  

Microsoft Academic Search

We examined the mechanism responsible for low reproductive success in leatherback turtles (Dermochelys coriacea) at Playa Grande, Costa Rica: low egg fertilization versus high rates of embryonic death. Leatherbacks at this beach had a high rate of fertility (X=93.3%±2.5%, n=819). We incubated 10 eggs from every clutch encountered of 19 females during 3 months of the 1998–1999 nesting season. Fertility

Barbara A. Bell; James R. Spotila; Frank V. Paladino; Richard D. Reina

2004-01-01

17

Potential liability of reproductive endocrinologists for high order multiple gestation  

PubMed Central

Background In light of the recent octuplet birth and the accompanying intensive media coverage, there has been much attention on high order multiple births resulting from assisted reproductive technology. Objectives The purpose of this commentary is to review 1) the relative contribution of ART to high order multiple gestation and its impact on infant morbidity, mortality, and health care dollar loss; 2) American Society of Reproductive Medicine’s guidelines for the number of embryos transferred in ART; and 3) how reproductive endocrinologists can lessen their exposure to litigation by following the ASRM guidelines for the number of embryos transferred and documenting proper informed consent in the medical records. Recommendations In situations in which the number of embryos transferred is in excess of the ASRM guidelines, justification for deviating from the ASRM guidelines should be justifiable and documented in the medical records.

Phelps, John

2010-01-01

18

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...

19

Ma×imum reproductive rate of fish at low population sizes  

Microsoft Academic Search

We examine a database of over 700 spawner-recruitment series to search for parameters that are constant, or nearly so, at the level of a species or above. We find that the number of spawners produced per spawner each year at low populations, i.e., the maximum annual reproductive rate, is relatively constant within species and that there is relatively little variation

Ransom A. Myers; Keith G. Bowen; Nicholas J. Barrowman

1999-01-01

20

Human disturbance influences reproductive success and growth rate in California sea lions (Zalophus californianus).  

PubMed

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

21

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.

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

2011-01-01

22

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

23

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

24

The implication of BLV infection in the productivity, reproductive capacity and survival rate of a dairy cow.  

PubMed

The objective of the present study was to find out whether BLV infection, known to cause immunodisturbances in cows, might also bring about decreased productivity, reproductive rate and a shorter life span. More than 100 pairs of dairy cows, and a whole population of 3000 milch cows, were studied for this report. The findings revealed that a BLV-positive cow had a shorter life span than both its seronegative counterpart and the entire milch cow population. It also produced a total of 3.5% less milk and had a mean of 48 more days open than did the BLV-negative cow. The differences in survival rate were highly significant, while, at a level of 5%, those of productivity and reproductive rate were not. The implications of these findings are discussed. A highly significant correlation was also shown between BLV infection and the persistence of Trichophyton verrucosum infection in cows. The presented data indicate that BLV infection might affect the immune system of a cow to such a degree that it ceases to be productive enough to be kept within a herd. Thus it is usually culled before any severe symptoms of disease emerge. PMID:2560862

Brenner, J; Van-Haam, M; Savir, D; Trainin, Z

1989-10-01

25

Genomic mutation rates for lifetime reproductive output and lifespan in Caenorhabditis?elegans  

PubMed Central

Theory concerning the evolution of sex and recombination and mutation load relies on information on rates and distributions of effects of deleterious mutations. Direct information on the genomic mutation rate in Drosophila implies that an accumulation of mildly deleterious mutations reduces viability of populations by at least 1% per generation. We carried out an experiment to measure the deleterious mutation rate in Caenorhabditis elegans, in which independent sublines were maintained with one hermaphrodite parent per generation, conditions that minimize the opportunity for natural selection and lead to random fixation of deleterious mutations. After 60 generations of mutation accumulation, negligible changes in mean reproductive output and lifespan occurred, but the genetic variance increased at rates typical for life history traits in other species. The estimated deleterious mutation rate per haploid genome for fitness, U, was 0.0026, a figure two orders of magnitude smaller than previously measured for viability in Drosophila.

Keightley, Peter D.; Caballero, Armando

1997-01-01

26

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

27

Influence of advanced age on the blastocyst development rate and pregnancy rate in assisted reproductive technology  

Microsoft Academic Search

Objective: To evaluate the percentage of blastocysts developing, the pregnancy rate, the implantation rate, and the abortion rate in women >40 years of age using a cell-free culture system for the development of viable human blastocysts.Design: Retrospective clinical study.Setting: Private IVF units.Patient(s): Two hundred ninety-three cycles in patients undergoing IVF treatment for infertility. Sixty-two cycles were in patients ?40 years

Kostas Pantos; Vasilis Athanasiou; Konstantinos Stefanidis; Dimitris Stavrou; Terpsi Vaxevanoglou; Margarita Chronopoulou

1999-01-01

28

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

29

Fatty Acid Composition of Human Follicular Fluid Phospholipids and Fertilization Rate in Assisted Reproductive Techniques  

PubMed Central

Background: Fatty acids are known to be critically important in multiple biological functions. Phospholipid fatty acids of follicular fluid, an important microenvironment for the development of oocytes, may contribute to the women’s fertility and the efficacy of assisted reproduction techniques. The aim of this study was to investigate the effect of fatty acid composition of follicular fluid phospholipids on women undergoing assisted reproductive techniques. Methods: Follicular fluid samples were obtained from 100 patients, referred to Tabriz Alzahra Hospital. Seventy-nine subjects underwent in vitro fertilization (IVF) and the remaining 21 underwent intracytoplasmic sperm injection (ICSI). Total lipid of follicular fluid was extracted and fatty acids were analyzed by gas-liquid chromatography. Results: Saturated fatty acids (SFA, P = 0.002) and the ratio of SFA to polyunsaturated fatty acids (P = 0.001) were correlated negatively with a number of mature oocytes after age adjustment. Linoleic acid (P = 0.006) was positively correlated, while the level of arachidonic acid was negatively correlated with fertility percentage after adjustment for body mass index, sperm count, sperm motility. Conclusion: Since phospholipids are one of the major components of lipid metabolism, the results of this study highlight the importance of this component in follicular fluid lipid metabolism. Consequently, it is proposed as an index in determination of the rate of success in assisted reproductive techniques such as IVF/ICSI.

Shaaker, Maghsod; Rahimipour, Ali; Nouri, Mohammad; Khanaki, Korosh; Darabi, Masoud; Farzadi, Laya; Shahnazi, Vahideh; Mehdizadeh, Amir

2012-01-01

30

Cytoplasmically Inherited Reproductive Incompatibility in Tribolium Flour Beetles: The Rate of Spread and Effect on Population Size  

PubMed Central

This paper reports on the effects of a cytoplasmically inherited reproductive incompatibility in different genetic strains of the flour beetle, Tribolium confusum. We measured the rate of spread and the effect of host population size using different initial frequencies of infection with a cytoplasmic factor that mediates reproductive incompatibility. There were two experiments, in one the infected and uninfected lines were from the same genetic strain, b-Yugoslavia. In the other, the infected line was from the ``high cannibalism'' bIV strain and the uninfected line from the ``low cannibalism'' bI strain. We estimate that the fitness ratio of infected to uninfected in b-Yugoslavia is 0.63 and the observed rate of spread for this strain corresponds to a model of cytoplasmic inheritance that takes into account the productivity differences between the infected and cured lines. In the bI-bIV experiment, because the uninfected and infected lines are from different genetic strains, we cannot partition the effects of the cytoplasmic factor from other factors. The rate of spread in the bI-bIV experiment is faster in males and slower in females than predicted from a model of cytoplasmic inheritance. In both experiments, productivity varies with initial infection frequency; however, the relationship is not explained by a simple model that predicts lower population size at intermediate infection frequencies.

Stevens, L.; Wade, M. J.

1990-01-01

31

Individualised controlled ovarian stimulation (iCOS): maximising success rates for assisted reproductive technology patients  

PubMed Central

Background In the last two decades, pregnancy rates for patients undergoing in-vitro fertilisation (IVF) have significantly increased. Some of the major advances responsible for this improvement were the introduction of controlled ovarian stimulation (COS) for the induction of multiple follicle development, and the utilisation of mid-luteal gonadotropin-releasing hormone agonists to achieve pituitary down-regulation and full control of the cycle. As a result, a combination of a gonadotropin-releasing hormone agonist with high doses (150-450 IU/day) of recombinant follicle-stimulating hormone has become the current standard approach for ovarian stimulation. However, given the heterogeneity of patients embarking on IVF, and the fact that many different drugs can be used alone or in different combinations (generating multiple potential protocols of controlled ovarian stimulation), we consider the need to identify special populations of patients and adapt treatment protocols accordingly, and to implement a more individualised approach to COS. Discussion Studies on mild, minimal and natural IVF cycles have yielded promising results, but have focused on fresh embryo transfers and included relatively young patient populations who generally have the potential for more favourable outcomes. The efficacy of these protocols in patients with a poorer prognosis remains to be tested. When comparing protocols for COS, it is important to think beyond current primary endpoints, and to consider the ideal quality and quantity of oocytes and embryos being produced per stimulated patient, in order to achieve a pregnancy. We should also focus on the cumulative pregnancy rate, which is based on outcomes from fresh and frozen embryos from the same cycle of stimulation. Individualised COS (iCOS) determined by the use of biomarkers to test ovarian reserve has the potential to optimise outcomes and reduce safety issues by adapting treatment protocols according to each patient's specific characteristics. As new objective endocrine, paracrine, functional and/or genetic biomarkers of response are developed, iCOS can be refined further still, and this will be a significant step towards a personalised approach for IVF. Conclusions A variety of COS protocols have been adopted, with mixed success, but no single approach is appropriate for all patients within a given population. We suggest that treatment protocols should be adapted for individual patients through iCOS; this approach promises to be one of the first steps towards implementing personalised medicine in reproductive science.

2011-01-01

32

1995 Assisted Reproductive Technology Success Rates: National Summary and Fertility Clinic Reports  

NSDL National Science Digital Library

The first national guide to information on the success rate of 281 fertility clinics around the country resides at this site. Issued by the US Centers for Disease Control, the full text of the report offers a clinic-by-clinic guide to summary statistics on the success of numerous methods of assisted reproductive technology (ART) including a variety of in vitro techniques. Based on 59,142 treatments that resulted in 11,315 live births in 1995, the report contains information on percentages of multiple births, information about the diagnoses of patients and age-specific success rates. This report is a response to a 1992 Congressional measure requiring the CDC to publish fertility clinic statistics for consumers.

33

Parental investment, potential reproductive rates, and mating system in the strawberry dart-poison frog, Dendrobates pumilio  

Microsoft Academic Search

We studied the effect of relative parental investment on potential reproductive rates (PRRs) to explain sex differences in\\u000a selectivity and competition in the dart-poison frog Dendrobates pumilio. We recorded the reproductive behavior of this species in a Costa Rican lowland rainforest for almost 6?months. Females spent\\u000a more time on parental care than males, and `time out' estimates suggest that PRRs

Heike Pröhl; Walter Hödl

1999-01-01

34

Effects of intraspecific variation in reproductive traits, pectoral fin use and burst swimming on metabolic rates and swimming performance in the Trinidadian guppy (Poecilia reticulata).  

PubMed

There is considerable intraspecific variation in metabolic rates and locomotor performance in aquatic ectothermic vertebrates; however, the mechanistic basis remains poorly understood. Using pregnant Trinidadian guppies (Poecilia reticulata), a live-bearing teleost, we examined the effects of reproductive traits, pectoral fin use and burst-assisted swimming on swimming metabolic rate, standard metabolic rate (O2std) and prolonged swimming performance (Ucrit). Reproductive traits included reproductive allocation and pregnancy stage, the former defined as the mass of the reproductive tissues divided by the total body mass. Results showed that the metabolic rate increased curvilinearly with swimming speed. The slope of the relationship was used as an index of swimming cost. There was no evidence that reproductive traits correlated with swimming cost, O2std or Ucrit. In contrast, data revealed strong effects of pectoral fin use on swimming cost and Ucrit. Poecilia reticulata employed body-caudal fin (BCF) swimming at all tested swimming speeds; however, fish with a high simultaneous use of the pectoral fins exhibited increased swimming cost and decreased Ucrit. These data indicated that combining BCF swimming and pectoral fin movement over a wide speed range, presumably to support swimming stability and control, is an inefficient swimming behaviour. Finally, transition to burst-assisted swimming was associated with an increase in aerobic metabolic rate. Our study highlights factors other than swimming speed that affect swimming cost and suggests that intraspecific diversity in biomechanical performance, such as pectoral fin use, is an important source of variation in both locomotor cost and maximal performance. PMID:23737561

Svendsen, Jon C; Banet, Amanda I; Christensen, Rune H B; Steffensen, John F; Aarestrup, Kim

2013-09-15

35

Bacterial colonization of the uterine cervix and success rate in assisted reproduction: results of a prospective survey  

Microsoft Academic Search

BACKGROUND: Overgrowth of bacteria in the birth canal is associated with an increased risk of late miscarriage, preterm labour, post-partum endometritis and low birthweight. Conception rates in assisted reproduction treatments (ART) remain frustratingly low. We examined whether the nature of bacterial flora, found in the uterine cervical canal at embryo transfer, is associated with the rate of conception in ART.

Raed Salim; Izhar Ben-Shlomo; Raul Colodner; Yoram Keness; Eliezer Shalev

36

Low reproductive performance and high sow mortality in a pig breeding herd: a case study  

PubMed Central

Sow performance is a key component of the productivity of commercial pig farms. Reproductive failure in the sow is common in pig production. For every 100 sows served, 89 should farrow. In absence of specific diseases such as porcine parvovirus, pseudo-rabies, swine fever, leptospirosis and brucellosis, management failures are the most important causes of loss. A syndrome associated with reproductive inefficiency, and post-service vaginal discharge and high sow mortality in a commercial pig farm is described. Pregnancy failures exceeded 20% and sow mortality exceeded 12% for two consecutive years. The abnormal post-service vaginal discharge rate was 1.7% during the period of investigation. An investigation involving an analysis of farm records, a review of breeding management practices, clinical examinations, laboratory analysis and examination of urogenital organs was conducted. The main contributing factors found were a sub-optimal gilt breeding management, an inadequate culling policy in combination with a sub-optimal culling rate and the presence of cystitis in more than 1% of the urogenital organs examined. The high sow mortality rate was related to an aged breeding herd. A control programme was recommended based on management changes involving oestrus detection, movement of gilts post-service, hygiene in the service area, boar exposure post-service and urinary acidification. This programme failed to increase the farrowing rate due to incomplete implementation of the recommendations made. The farrowing rate increased to 86.5% subsequent to a farm manager change in January 2005, which resulted in complete implementation of the control programme.

2008-01-01

37

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

38

High burn rate solid composite propellants  

Microsoft Academic Search

High burn rate propellants help maintain high levels of thrust without requiring complex, high surface area grain geometries. Utilizing high burn rate propellants allows for simplified grain geometries that not only make production of the grains easier, but the simplified grains tend to have better mechanical strength, which is important in missiles undergoing high-g accelerations. Additionally, high burn rate propellants

Timothy D. Manship

2010-01-01

39

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

40

Instructed heart rate control in a high heart rate population  

Microsoft Academic Search

Forty college students were selected from a large number of introductory psychology students on the basis of high heart rate during an initial screening session. Subjects were then contacted and participated in two additional sessions during which heart rate, respiration rate, and skin conductance measures were obtained. Each session consisted of a baseline period followed by five trial periods during

Craig T. Twentyman; Paul F. Malloy; Alex S. Green

1979-01-01

41

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.

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

2009-01-01

42

A Data Mining Approach for Predicting the Pregnancy Rate in Human Assisted Reproduction  

Microsoft Academic Search

\\u000a One of the most relevant aspects in human assisted reproduction is to decide if, at a given moment, the endometrium is receptive\\u000a for embryo implantation, in order to perform embryo transfer cycle or to postpone it in another cycle. This might increase\\u000a both patients’ convenience and the cost-effectiveness of the assisted reproduction procedure. To help human experts in taking\\u000a this

Loris Nanni; Claudio Manna

43

Energetics of growth and reproduction in a high-tidal population of the clam Ruditapes decussatus from Urdaibai Estuary (Basque Country, N. Spain)  

NASA Astrophysics Data System (ADS)

Energetics of growth and reproduction were studied in a high-tidal population of the clam Ruditapes decussatus living in the Mundaka Estuary in the Biosphere Reserve of Urdaibai (Basque Country, North Spain). The study included an analysis of growth rings on the shells to establish the growth curve as well as seasonal patterns of growth and body condition, and estimates of the breeding cycle including quantification of the reproductive output and reproductive effort. The simultaneous determination of the seasonal course of metabolism allowed estimates of assimilation, growth efficiency and reproductive costs. Growth rates were consistently lower in this population than in other populations from similar latitudes, and this effect is interpreted in terms of nutritional restrictions caused by the high tidal position of the population. Assimilation rapidly increased from March to July, as a consequence of optimal nutritional conditions and increasing water temperatures. Somatic growth (spring) and gonadal development (early summer) both took place during this period. Negative growth was restricted to the winter and late summer and was associated with poor nutritional conditions (winter) and high rates of metabolic expenditure induced by high temperatures (late summer). Net growth efficiencies (ranging from 27% in 1-y-old to 6% in 7-y-old individuals) ranked among the lowest recorded for populations of marine bivalves. Reduced reproductive-effort values were consistent with the poor growing conditions that appeared to characterise this population of clams.

Urrutia, M. B.; Ibarrola, I.; Iglesias, J. I. P.; Navarro, E.

1999-08-01

44

A HIGH-THROUGHPUT METHOD FOR ASSESSING CHEMICAL TOXICITY USING A CAENORHABDITIS ELEGANS REPRODUCTION ASSAY  

PubMed Central

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. EC50 values for cadmium for automated measurements (176-192 ?M) were comparable to those previously reported for a 72-h exposure using manual counting (151 ?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.; McBride, Sandra J.; Rice, Julie R.; Snyder, Daniel W.; Freedman, Jonathan H.

2010-01-01

45

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...

46

Sperm chromatin structure correlates with spontaneous abortion and multiple pregnancy rates in assisted reproduction  

Microsoft Academic Search

The objective of this study was to determine if a relationship exists between sperm parameters, measured by sperm chromatin structure assay (SCSA), and spontaneous abortion and multiple births in couples undergoing assisted reproduction treatment. Retrospective analysis of infertility treatment outcomes and occurrence of spontaneous abortion and multiple births was conducted in 233 couples who underwent treatment by intracytoplasmic sperm injection

C. Kennedy; P. Ahlering; H. Rodriguez; S. Levy; P. Sutovsky

2011-01-01

47

Treatment of male mice with gonadotropins to improve the fertilization rate and reproduction.  

PubMed

The possibility of modifying the genome in mice has led to an exponential increase in the number of strains that have been developed for biomedical research. This will continue during the next few decades because international programmes plan to develop genetically-modified strains for every known mouse gene. Due to our own experiences and that of colleagues we know that the reproductive performance of many of these modified stains is impeded, despite that the modification is independent from genes that control reproduction. In some cases the spermatogenesis might be disturbed. The reason presumably lies in a defective endocrine function of the testes. This can cause reduced and/or abnormal sperm production. In livestock as well as in humans these disorders can be treated with gonadotropins. One treatment period lasts for the duration of spermatogenesis of the respective species. Up to now, nothing is known about such treatments in laboratory mice to restore or increase reproduction of genetically-modified strains. Spermatogenesis in the mouse lasts approximately 35 days. Therefore, we treated sexually mature male mice of C57BL/6 and BALB/c strains with gonadotropins for this period. The aim of this study was to test the principle suitability of such treatment for the improvement of sperm count, sperm motility, fertilization ability and reproduction. PMID:23230225

Glage, S; Wittur, I; Elfers, C; Hedrich, H J; Dorsch, M

2013-01-01

48

Assisted Reproductive Technology Success Rates: National Summary and Fertility Clinic Reports, 2002.  

National Technical Information Service (NTIS)

For many people who want to start a family, the dream of having a child is not easily realized; about 15% of women of childbearing age in the United States have received an infertility service. Assisted reproductive technology (ART) has been used in the U...

2004-01-01

49

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

50

Assisted Reproductive Technology Success Rates, 2000. National Summary and Fertility Clinic Report.  

National Technical Information Service (NTIS)

For many people who want to start a family, the dream of having a child is not easily realized; about 15% of women of childbearing age in the United States have received an infertility service. Assisted reproductive technology (ART) has been used in the U...

2002-01-01

51

Assisted Reproductive Technology Success Rates: National Summary and Fertility Clinic Reports, 2003.  

National Technical Information Service (NTIS)

For many people who want to start a family, the dream of having a child is not easily realized; about 12% of women of childbearing age in the United States have received an infertility service. Assisted reproductive technology (ART) has been used in the U...

2005-01-01

52

Assisted Reproductive Technology Success Rates: National Summary and Fertility Clinic Reports, 2004.  

National Technical Information Service (NTIS)

For many people who want to start a family, the dream of having a child is not easily realized; about 12% of women of childbearing age in the United States have received an infertility service. Assisted reproductive technology (ART) has been used in the U...

2006-01-01

53

Assisted Reproductive Technology Success Rates, 2001. National Summary and Fertility Clinic Reports.  

National Technical Information Service (NTIS)

For many people who want to start a family, the dream of having a child is not easily realized; about 15% of women of childbearing age in the United States have received an infertility service. Assisted reproductive technology (ART) has been used in the U...

2003-01-01

54

Assisted Reproductive Technology Success Rates, 1998. National Summary and Fertility Clinic Reports.  

National Technical Information Service (NTIS)

For many people who want to start a family, the dream of having a child is not easily realized; about 15% of women of childbearing age in the United States have received an infertility service. Assisted reproductive technology (ART) has been used in the U...

2000-01-01

55

Assisted Reproductive Technology Success Rates, 1999. National Summary and Fertility Clinic Reports.  

National Technical Information Service (NTIS)

For many people who want to start a family, the dream of having a child is not easily realized; about 15% of women of childbearing age in the United States have received an infertility service. Assisted reproductive technology (ART) has been used in the U...

2001-01-01

56

Female modulation of reproductive rate and its role in postmating prezygotic isolation in Callosobruchus maculatus  

Microsoft Academic Search

Summary 1. Mechanisms that come into play after mating but prior to fertilization can prevent hybrid formation and thus promote reproductive isolation. Recent research indicates that the evolution of such barriers to gene exchange between incipient forms appears to be common and is essential for speciation. 2. We aimed to test if female Bean Weevils ( Callosobruchus maculatus ) modulate

C. FRICKE; G. ARNQVIST; N. AMARO

2006-01-01

57

Fifty fertile years: anthropologists' studies of reproduction in high altitude natives.  

PubMed

Early European colonists of the Andes had difficulties in reproducing, a fact that underpins the hypothesis that reproduction is impaired amongst all humans at high altitudes. Yet a 16th century missionary wrote, "… the Indians are healthiest and where they multiply the most prolifically is in these same cold air-tempers, … [yet most children of the Spaniards] when born in such regions do not survive." These observations suggest that humans at high altitudes are subjected to strong natural selection from hypoxia, cold and limited food sources and, furthermore, that human populations can and have adapted, and continue to adapt, to these conditions. Informed by multiple approaches and theoretical frameworks, anthropologists have investigated to what extent and precisely how high altitude environments impact human reproductive functioning and fertility. Analyses of the proximate determinants of natural fertility suggest that behaviors (breast/infant feeding practices in the Andes, and marriage practices and religious celibacy in the Himalaya) are major determinants of fertility in high altitude populations. Furthermore, data from Project REPA (Reproduction and Ecology in Provincía Aroma), a longitudinal study in rural Bolivia, demonstrate that fecundity is not impaired in this indigenous altiplano population, and that the risk for early pregnancy loss (EPL) is not elevated by environmental hypoxia but does vary seasonally with the agricultural cycle (contra to the assumption that EPLs are due almost entirely to genetically flawed concepti). This review discusses these and other findings that reveal the complex and dynamic adaptations of human reproductive functioning in high altitude environments. PMID:23382088

Vitzthum, Virginia J

2013-01-01

58

Hard times in the city - attractive nest sites but insufficient food supply lead to low reproduction rates in a bird of prey  

PubMed Central

Introduction Urbanization is a global phenomenon that is encroaching on natural habitats and decreasing biodiversity, although it is creating new habitats for some species. The Eurasian kestrel (Falco tinnunculus) is frequently associated with urbanized landscapes but it is unclear what lies behind the high densities of kestrels in the urban environment. Results Occupied nest sites in the city of Vienna, Austria were investigated along a gradient of urbanization (percentage of land covered by buildings or used by traffic). Field surveys determined the abundance of potential prey (birds and rodents) and the results were compared to the birds’ diets. A number of breeding parameters were recorded over the course of three years. The majority of kestrels breed in semi-natural cavities in historic buildings. Nearest neighbour distances (NND) were smallest and reproductive success lowest in the city centre. Abundance of potential prey was not found to relate to the degree of urbanization but there was a significant shift in the birds’ diets from a heavy reliance on rodents in the outskirts of the city to feeding more on small birds in the centre. The use of urban habitats was associated with higher nest failure, partly associated with predation and nest desertion, and with significantly lower hatching rates and smaller fledged broods. Conclusions High breeding densities in urban habitats do not necessarily correlate with high habitat quality. The high density of kestrel nests in the city centre is probably due to the ready availability of breeding cavities. Highly urbanized areas in Vienna are associated with unexpected costs for the city dwelling-raptor, in terms both of prey availability and of reproductive success. The kestrel appears to be exploiting the urban environment but given the poor reproductive performance of urban kestrels it is likely that the species is falling into an ecological trap.

2014-01-01

59

Complete Genome Sequence of a Novel Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus Variant  

PubMed Central

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.

Wang, Lianghai; Hou, Jun; Zhang, Hexiao

2012-01-01

60

High shear rate characterization of magnetorheological fluids  

NASA Astrophysics Data System (ADS)

Shear mode or rotary drum-type magnetorheological energy absorbers (MREAS) are an attractive option for use in occupant or payload protection systems that operate at shear rates well over 25,000 s-1. However, their design is still performed using material properties measured using low-shear rate (<1,000 s-1) characterization techniques. This paper details a method for characterizing MR fluids at high shear rates, and presents characterization results for three commercially available MR fluids. It is proposed to utilize the perspective of apparent viscosity (the ratio of shear stress over shear rate) vs. shear rate to describe the behavior of the fluid at these shear rates. Good agreement between the measured data and predictions of MR fluid behavior are achieved using this framework. By expanding the knowledge of MR fluid behavior to these high shear strain rates, the design of MREAs is enabled for occupant protection systems for crash and mine blast events.

Becnel, Andrew C.; Hu, Wei; Wereley, Norman M.

2012-03-01

61

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

62

High burn rate solid composite propellants  

NASA Astrophysics Data System (ADS)

High burn rate propellants help maintain high levels of thrust without requiring complex, high surface area grain geometries. Utilizing high burn rate propellants allows for simplified grain geometries that not only make production of the grains easier, but the simplified grains tend to have better mechanical strength, which is important in missiles undergoing high-g accelerations. Additionally, high burn rate propellants allow for a higher volumetric loading which reduces the overall missile's size and weight. The purpose of this study is to present methods of achieving a high burn rate propellant and to develop a composite propellant formulation that burns at 1.5 inches per second at 1000 psia. In this study, several means of achieving a high burn rate propellant were presented. In addition, several candidate approaches were evaluated using the Kepner-Tregoe method with hydroxyl terminated polybutadiene (HTPB)-based propellants using burn rate modifiers and dicyclopentadiene (DCPD)-based propellants being selected for further evaluation. Propellants with varying levels of nano-aluminum, nano-iron oxide, FeBTA, and overall solids loading were produced using the HTPB binder and evaluated in order to determine the effect the various ingredients have on the burn rate and to find a formulation that provides the burn rate desired. Experiments were conducted to compare the burn rates of propellants using the binders HTPB and DCPD. The DCPD formulation matched that of the baseline HTPB mix. Finally, GAP-plasticized DCPD gumstock dogbones were attempted to be made for mechanical evaluation. Results from the study show that nano-additives have a substantial effect on propellant burn rate with nano-iron oxide having the largest influence. Of the formulations tested, the highest burn rate was a 84% solids loading mix using nano-aluminum nano-iron oxide, and ammonium perchlorate in a 3:1(20 micron: 200 micron) ratio which achieved a burn rate of 1.2 inches per second at 1000 psia. In addition, DCPD propellant was shown to burn at twice the rate of HTPB propellant, most likely a result of its lower decomposition temperature. A high burn rate DCPD propellant was developed, but due to poor wetting, the resulting propellant was brittle and fragmented during strand burn testing. Lastly, GAP-plasticized DCPD gumstocks were not able to be produced most likely due to an interaction between GAP and the cure catalyst for DCPD.

Manship, Timothy D.

63

High Rate Primary Zinc/Air Battery.  

National Technical Information Service (NTIS)

A system study of the high rate throwaway battery determined that thick anodes discharged to high efficiency were necessary for high energy density and minimum cost. Laboratory investigation indicated that .250 inch zinc anodes operating at 43 mA/sq cm co...

E. G. Katsoulis B. Randall S. Cohen

1968-01-01

64

Rate Sensitivity of High Strength Syntactic Foam.  

National Technical Information Service (NTIS)

A series of dynamic experiments was performed on high crush strength syntactic foam to characterize how rate affects the compressive and tensile properties of the material. The Investigation was carried out as part of a larger effort to develop a rate sen...

R. Doleski S. Plunkett W. Tucker

2003-01-01

65

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

66

ISS Update: High Rate Communications System  

NASA Video Gallery

ISS Update Commentator Pat Ryan interviews Diego Serna, Communications and Tracking Officer, about the High Rate Communications System. Questions? Ask us on Twitter @NASA_Johnson and include the ha...

67

High Rate Primary Zinc/Air Battery.  

National Technical Information Service (NTIS)

The materials and processing costs of the cathode for the high rate primary battery were investigated to achieve an effective cost reduction while still maintaining performance and reliability. Concurrent with this investigation, development of both paste...

E. G. Katsoulis B. Randall

1968-01-01

68

Does the silver moss Bryum argenteum exhibit sex-specific patterns in vegetative growth rate, asexual fitness or prezygotic reproductive investment?  

PubMed Central

Background and Aims Expected life history trade-offs associated with sex differences in reproductive investment are often undetected in seed plants, with the difficulty arising from logistical issues of conducting controlled experiments. By controlling genotype, age and resource status of individuals, a bryophyte was assessed for sex-specific and location-specific patterns of vegetative, asexual and sexual growth/reproduction across a regional scale. Methods Twelve genotypes (six male, six female) of the dioecious bryophyte Bryum argenteum were subcultured to remove environmental effects, regenerated asexually to replicate each genotype 16 times, and grown over a period of 92 d. Plants were assessed for growth rates, asexual and sexual reproductive traits, and allocation to above- and below-ground regenerative biomass. Key Results The degree of sexual versus asexual reproductive investment appears to be under genetic control, with three distinct ecotypes found in this study. Protonemal growth rate was positively correlated with asexual reproduction and sexual reproduction, whereas asexual reproduction was negatively correlated (appeared to trade-off) with vegetative growth (shoot production). No sex-specific trade-offs were detected. Female sex-expressing shoots were longer than males, but the sexes did not differ in growth traits, asexual traits, sexual induction times, or above- and below-ground biomass. Males, however, had much higher rates of inflorescence production than females, which translated into a significantly higher (24x) prezygotic investment for males relative to females. Conclusions Evidence for three distinct ecotypes is presented for a bryophyte based on regeneration traits. Prior to zygote production, the sexes of this bryophyte did not differ in vegetative growth traits but significantly differed in reproductive investment, with the latter differences potentially implicated in the strongly biased female sex ratio. The disparity between males and females for prezygotic reproductive investment is the highest known for bryophytes.

Horsley, Kimberly; Stark, Lloyd R.; McLetchie, D. Nicholas

2011-01-01

69

Microstructural Evolution in High Strain, High Strain-Rate Deformation.  

National Technical Information Service (NTIS)

Under high strain rates, plastic deformation can be assumed to be adiabatic, and a significant temperature increase can occur at large strains. In this study, shock-hardened polycrystalline copper was subjected to high strains at high strain rates using a...

K. S. Vecchio U. Andrade M. A. Meyers L. W. Meyer

1991-01-01

70

Very high speed rate shaping fuel injector  

US Patent & Trademark Office Database

A very high speed injector permits injecting high pressure diesel oil directly into a diesel engine combustion chamber. The very high speed permits almost arbitrary rate shaping, minimizing formation of diesel particulate matter and oxides of nitrogen pollutants. An electrical waveform is pre-determined for a desired fuel injection rate shape. The electrical waveform is converted into a corresponding magnetic field waveform by a solenoid coil. A giant magnetostrictive material (GMM) transduces the magnetic field waveform into a corresponding mechanical waveform. The mechanical waveform positions a valve element to control flow rate. The very high speed features include a thin solenoid coil of relatively few turns, proportionally supplying up to one hundred amperes at up to one hundred volts in no greater than ten microseconds, the GMM is subject to a bias compressive stress magnitude of no less than fourteen megapascals, and the magnetic flux path is minimized and designed to suppress eddy currents.

2007-08-14

71

Fifty fertile years: Anthropologists' studies of reproduction in high altitude natives.  

PubMed

Early European colonists of the Andes had difficulties in reproducing, a fact that underpins the hypothesis that reproduction is impaired amongst all humans at high altitudes. Yet a 16th century missionary wrote, "… the Indians are healthiest and where they multiply the most prolifically is in these same cold air-tempers, … [yet most children of the Spaniards] when born in such regions do not survive." These observations suggest that humans at high altitudes are subjected to strong natural selection from hypoxia, cold and limited food sources and, furthermore, that human populations can and have adapted, and continue to adapt, to these conditions. Informed by multiple approaches and theoretical frameworks, anthropologists have investigated to what extent and precisely how high altitude environments impact human reproductive functioning and fertility. Analyses of the proximate determinants of natural fertility suggest that behaviors (breast/infant feeding practices in the Andes, and marriage practices and religious celibacy in the Himalaya) are major determinants of fertility in high altitude populations. Furthermore, data from Project REPA (Reproduction and Ecology in Provincía Aroma), a longitudinal study in rural Bolivia, demonstrate that fecundity is not impaired in this indigenous altiplano population, and that the risk for early pregnancy loss (EPL) is not elevated by environmental hypoxia but does vary seasonally with the agricultural cycle (contra to the assumption that EPLs are due almost entirely to genetically flawed concepti). This review discusses these and other findings that reveal the complex and dynamic adaptations of human reproductive functioning in high altitude environments. Am. J. Hum. Biol., 2013. © 2013 Wiley Periodicals, Inc. PMID:23362150

Vitzthum, Virginia J

2013-01-30

72

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

73

Length frequency distribution, mortality rate and reproductive biology of kawakawa (Euthynnus affinis-Cantor, 1849) in the coastal waters of Tanzania.  

PubMed

This study explored important aspect of the basis for the highly complex population of kawakawa (Euthynnus affinis) within the coastal waters of Tanzania; by investigating length frequency distribution, mortality rate and reproductive characteristics. This information is essential for the sustainable management of the regionally-important recreational and economic E. affinis fishery. Fish were sampled on a monthly basis for two monsoon seasons using a ring net and artisanal fishermen boat. Maximum and minimum total length was 85 and 31 cm, respectively. Nonlinear least square fitting provided a complete set of von Bertalanffy growth estimates: L8 = 89.25 cm total length and K = 0.78. The estimated value of total mortality based on length converted catch curve using these growth parameters is Z = 1.78 year(-1). Natural mortality based on growth parameters and mean environmental temperature (T = 26.9 degrees C) is M = 1.09 year(-1). The estimated annual instantaneous fishing mortality (F = 0.69 year(-1)) was considerably grater than the target (Fopt = 0.43 year(-1)) and limit (Flimit = 0.58 year(-1)) biological reference point indicating that E. affinis is heavily overexploited. Reproductive aspects were assessed whereby female E. affinis was reported to reach maturity earlier than males which is an indication of phenotypic response toward a decline in population. Two peaks was revealed by the use of Gonad-Somatic Index (GSI), however an extended spawning period was noticed in a period between November to February following an increased water temperature. Although, these findings presents a snapshot concerning population structure and reproduction of E. affinis, further studies covering the entire coastal waters of Tanzania are recommended to aid the management and conservation strategies. PMID:24511734

Johnson, M G; Tamatamah, A R

2013-11-01

74

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

75

BEHAVIOUR OF HIGH-STRENGTH CONCRETE AT HIGH LOADING RATES  

Microsoft Academic Search

Cracks in plain concrete run along the boundary layer of the concrete-aggregate grain. The aggre- gate grains are pulled out from the surrounding cement paste under friction. This friction, which shows a partial viscous character, leads to an additional force transfer in the composite material at high rates of loading. In contrast, in high-strength concrete under low rates of loading,

S. Ortlepp; M. Curbach

76

Reproductive effects of inorganic borates on male employees: birth rate assessment.  

PubMed Central

The purpose of this study was to investigate the potential for reproductive effects of inorganic borate compounds on male employees. The standardized birth ratio (SBR) methodology was used to assess fertility among male employees, using live births as the measured end point. The ratio of female to male births was also assessed. Data were collected via questionnaires and telephone follow-up interviews. Medical insurance records were assessed for nonresponders. Exposures were assessed using three semiquantitative categories. We found a statistically significant increase in fertility as measured by live births among the employees of the inorganic borate facility. There does not appear to be any decrease in fertility due to exposures either as analyzed by the borate exposure categories or over time, which is an indirect measure of exposures. We found a nonstatistically significant increase in the percentage of female offspring. This increase was due, not to a deficiency of male offspring, but rather to a marked increase in the numbers of female offspring. This increase in percentage female offspring does not appear to be related to exposures to inorganic borates. Based on the data, exposures to inorganic borates do not appear to adversely affect fertility in this population.

Whorton, D; Haas, J; Trent, L

1994-01-01

77

High Bit Rate Experiments Over ACTS  

NASA Technical Reports Server (NTRS)

This paper describes two high data rate experiments chat are being developed for the gigabit NASA Advanced Communications Technology Satellite (ACTS). The first is a telescience experiment that remotely acquires image data at the Keck telescope from the Caltech campus. The second is a distributed global climate application that is run between two supercomputer centers interconnected by ACTS. The implementation approach for each is described along with the expected results. Also. the ACTS high data rate (HDR) ground station is also described in detail.

Bergman, Larry A.; Gary, J. Patrick; Edelsen, Burt; Helm, Neil; Cohen, Judith; Shopbell, Patrick; Mechoso, C. Roberto; Chung-Chun; Farrara, M.; Spahr, Joseph

1996-01-01

78

Pros and cons of estimating the reproduction number from early epidemic growth rate of influenza A (H1N1) 2009  

Microsoft Academic Search

BACKGROUND: In many parts of the world, the exponential growth rate of infections during the initial epidemic phase has been used to make statistical inferences on the reproduction number, R, a summary measure of the transmission potential for the novel influenza A (H1N1) 2009. The growth rate at the initial stage of the epidemic in Japan led to estimates for

Hiroshi Nishiura; Gerardo Chowell; Muntaser Safan; Carlos Castillo-Chavez

2010-01-01

79

MST-5 High Rate Mechanical Testing Facility.  

National Technical Information Service (NTIS)

Selected aspects of five gun systems in the MST-5 High Rate Mechanical Testing Facility are described. 238 plutonium sources heated by a projectile furnace are impacted in a 7 in. gun system which provides impact containment. Failure strains in sheet meta...

C. E. Frantz

1985-01-01

80

MST5 high rate mechanical testing facility  

Microsoft Academic Search

Selected aspects of five gun systems in the MST-5 High Rate Mechanical Testing Facility are described. 238 plutonium sources heated by a projectile furnace are impacted in a 7 in. gun system which provides impact containment. Failure strains in sheet metals are determined by a biaxial punch test and a tensile test using a 2 in. bore gun. A similar

Frantz

1985-01-01

81

High Rate Primary Zinc/Air Battery.  

National Technical Information Service (NTIS)

The report describes the work performed during a one-year program to develop a high rate, primary zinc-air battery. The major portion of this report is concerned with the battery testing, and activated storage studies. Five-cell batteries of the final des...

E. G. Katsoulis B. Randall

1968-01-01

82

High sampling rate adaptive decision feedback equalizers  

Microsoft Academic Search

A parallel adaptive decision feedback equalizer (ADFE) architecture is proposed. It allows adaptation at every sample to effectively equalize intersymbol interference for applications that operate at high sampling rates and require fast tracking capability. It is shown that if the effect of error propagation is small, the filter coefficients of the parallel ADFE will be exactly the same as those

Alan Gatherer; T. H.-Y. Meng

1990-01-01

83

High Rate Filtration of Combined Sewer Overflows.  

National Technical Information Service (NTIS)

Pilot plant studies were conducted to develop and demonstrate the capabilities of the deep bed, dual media, high rate filtrate treatment process for storm caused combined sewer overflows. The treatment system is comprised of a drum screen with a 40 mesh s...

R. Nebolsine P. J. Harvey C. Y. Fan

1972-01-01

84

Understanding High School Graduation Rates in Indiana  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

85

Understanding High School Graduation Rates in Connecticut  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

86

Understanding High School Graduation Rates in Kentucky  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

87

Understanding High School Graduation Rates in Arizona  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

88

Understanding High School Graduation Rates in Arkansas  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

89

Understanding High School Graduation Rates in Alabama  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

90

Understanding High School Graduation Rates in Georgia  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

91

Understanding High School Graduation Rates in Minnesota  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

92

Understanding High School Graduation Rates in Maryland  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

93

Understanding High School Graduation Rates in Iowa  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

94

Understanding High School Graduation Rates in Maine  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

95

Understanding High School Graduation Rates in Florida  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

96

Understanding High School Graduation Rates in Delaware  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

97

Understanding High School Graduation Rates in Colorado  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

98

Understanding High School Graduation Rates in California  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

99

Understanding High School Graduation Rates in Kansas  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

100

Understanding High School Graduation Rates in Nebraska  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

101

Understanding High School Graduation Rates in Louisiana  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

102

Understanding High School Graduation Rates in Alaska  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

103

Understanding High School Graduation Rates in Michigan  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

104

Understanding High School Graduation Rates in Hawaii  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

105

Understanding High School Graduation Rates in Missouri  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

106

Understanding High School Graduation Rates in Massachusetts  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

107

Understanding High School Graduation Rates in Idaho  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

108

Understanding High School Graduation Rates in Illinois  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

109

Understanding High School Graduation Rates in Montana  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

110

Understanding High School Graduation Rates in Mississippi  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

111

Microalgal separation from high-rate ponds  

Microsoft Academic Search

High rate ponding (HRP) processes are playing an increasing role in the treatment of organic wastewaters in sunbelt communities. Photosynthetic oxygenation by algae has proved to cost only one-seventh as much as mechanical aeration for activated sludge systems. During this study, an advanced HRP, which produces an effluent equivalent to tertiary treatment has been studied. It emphasizes not only waste

Nurdogan

1988-01-01

112

High Repetition Rate Spark Gap. Final Report.  

National Technical Information Service (NTIS)

The objective of the program was to design, fabricate and test a high repetition rate spark gap to meet the following technical specifications: voltage--250 kV; applied voltage wave-voltage waveform above 150 kV for shape--2 mu sec prior to firing; curren...

1977-01-01

113

A miniature high repetition rate shock tube  

NASA Astrophysics Data System (ADS)

A miniature high repetition rate shock tube with excellent reproducibility has been constructed to facilitate high temperature, high pressure, gas phase experiments at facilities such as synchrotron light sources where space is limited and many experiments need to be averaged to obtain adequate signal levels. The shock tube is designed to generate reaction conditions of T > 600 K, P < 100 bars at a cycle rate of up to 4 Hz. The design of the apparatus is discussed in detail, and data are presented to demonstrate that well-formed shock waves with predictable characteristics are created, repeatably. Two synchrotron-based experiments using this apparatus are also briefly described here, demonstrating the potential of the shock tube for research at synchrotron light sources.

Tranter, R. S.; Lynch, P. T.

2013-09-01

114

A miniature high repetition rate shock tube.  

PubMed

A miniature high repetition rate shock tube with excellent reproducibility has been constructed to facilitate high temperature, high pressure, gas phase experiments at facilities such as synchrotron light sources where space is limited and many experiments need to be averaged to obtain adequate signal levels. The shock tube is designed to generate reaction conditions of T > 600 K, P < 100 bars at a cycle rate of up to 4 Hz. The design of the apparatus is discussed in detail, and data are presented to demonstrate that well-formed shock waves with predictable characteristics are created, repeatably. Two synchrotron-based experiments using this apparatus are also briefly described here, demonstrating the potential of the shock tube for research at synchrotron light sources. PMID:24089840

Tranter, R S; Lynch, P T

2013-09-01

115

High strain rate response of an elastomer.  

NASA Astrophysics Data System (ADS)

Pressure-shear plate impact experiments have been conducted to study the mechanical response of an elastomer (polyurea) at very high strain rates: 10^5 - 10^6 s-1. Thin samples are cast between two hard steel plates. Longitudinal waves reverberating through the sample are used to determine the slope of the isentrope at compressive stresses greater than, say, 500 MPa - the pressure at impact. Release wave experiments, combined with plane wave simulations, are used to extend the isentrope into the tensile regime. Because the shearing resistance of polyurea depends strongly on pressure, two approaches are used to investigate the regime of high shearing rate and low pressure. First, an unloading longitudinal wave reflected from the rear surface of the target assembly is made to arrive at the sample midway through its loading by the incident shear wave. As a result, the sample is sheared at high strain rates and both high and low pressure during a single experiment. Second, the thickness of the flyer and front plates are selected such that the compressive pulse passes through the cast-in-place sample before the shear wave arrives, allowing the shearing resistance to be measured at zero pressure. Results of these experiments and their simulation will be presented.

Jiao, Tong; Clifton, Rodney; Grunschel, Stephen

2007-06-01

116

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

117

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

118

Correlation between Endometrial Parameters in Doppler Sonography and Success Rate of Implantation in Assisted Reproductive Programs  

Microsoft Academic Search

Background: A good blood supply towards the endometrium is usually considered to be an essential requirement for implantation. Evaluating the role of endometrial and sub-endometrial blood flows detected by color Doppler sonography at the day of embryo transfer, as a predictor of pregnancy rate during IVF\\/ICSI programs was our main goal in this study. Materials and Methods: Seventy three infertile

Firoozeh Ahmadi; Ahmad Vosough; Shohreh Irani; Fatemeh Zafarani

119

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

120

Antimüllerian hormone levels are strongly associated with live-birth rates after assisted reproduction.  

PubMed

Context: Previous studies have suggested that antimüllerian hormone (AMH) levels are positively associated with in vitro fertilization (IVF) outcome through their relationship with oocyte yield and not by reflecting oocyte or embryo quality. Objective: The aim was to investigate whether AMH levels are associated with pregnancy and live-birth rates and whether the results may also reflect qualitative aspects of oocytes and embryos. Design: The study was a prospective cohort study between April 2008 and June 2011. Setting: The study was done at a university-affiliated private infertility center. Patients: The study cohort consisted of 892 consecutive women undergoing 1230 IVF-intracytoplasmic sperm injection cycles. Intervention(s): AMH levels, analyzed using the DSL ELISA kit, were statistically adjusted for repeated treatments and age and analyzed for associations with treatment outcome. Main Outcome Measures: Pregnancy rates, live-birth rates, and stimulation outcome parameters were measured. Results: AMH was log-normally distributed with a mean (SD) of 2.3 (2.5) ng/mL. Live-birth rates per started cycle (mean [95% confidence interval]) increased log-linearly from 10.7% [7.2-14.1] for AMH < 0.84 ng/mL (25th percentile) to 30.8% [25.7-36.0] for AMH > 2.94 ng/mL (75th percentile), Ptrend < .0001, being superior in women with polycystic ovaries. These findings were significant also after adjustments were made for age and oocyte yield. AMH was also associated with ovarian response variables and embryo scores. Conclusions: AMH is strongly associated with live-birth rates after IVF-intracytoplasmic sperm injection. AMH may therefore serve as a prognostic factor for the chance of a pregnancy and live birth. Treatment outcome was superior in patients with polycystic ovaries. The findings also indicate that AMH may partially comprise information about oocyte quality. PMID:23408576

Brodin, Thomas; Hadziosmanovic, Nermin; Berglund, Lars; Olovsson, Matts; Holte, Jan

2013-03-01

121

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

122

High strain rate damage of Carrara marble  

NASA Astrophysics Data System (ADS)

Several cases of rock pulverization have been observed along major active faults in granite and other crystalline rocks. They have been interpreted as due to coseismic pervasive microfracturing. In contrast, little is known about pulverization in carbonates. With the aim of understanding carbonate pulverization, we investigate the high strain rate (c. 100 s-1) behavior of unconfined Carrara marble through a set of experiments with a Split Hopkinson Pressure Bar. Three final states were observed: (1) at low strain, the sample is kept intact, without apparent macrofractures; (2) failure is localized along a few fractures once stress is larger than 100 MPa, corresponding to a strain of 0.65%; (3) above 1.3% strain, the sample is pulverized. Contrary to granite, the transition to pulverization is controlled by strain rather than strain rate. Yet, at low strain rate, a sample from the same marble displayed only a few fractures. This suggests that the experiments were done above the strain rate transition to pulverization. Marble seems easier to pulverize than granite. This creates a paradox: finely pulverized rocks should be prevalent along any high strain zone near faults through carbonates, but this is not what is observed. A few alternatives are proposed to solve this paradox.

Doan, Mai-Linh; Billi, Andrea

2011-10-01

123

High-rate vector quantization for detection  

Microsoft Academic Search

We investigate high-rate quantization for various detection and reconstruction loss criteria. A new distortion measure is introduced which accounts for global loss in best attainable binary hypothesis testing performance. The distortion criterion is related to the area under the receiver-operating-characteristic (ROC) curve. Specifically, motivated by Sanov's theorem, we define a performance curve as the trajectory of the pair of optimal

Riten Gupta; Alfred O. Hero III

2003-01-01

124

Factors affecting feeding rate, reproduction and growth of an oligochaete Lumbriculus variegatus (Müller)  

Microsoft Academic Search

Worm density of a deposit feeding oligochaete (Lumbriculus variegatus) did not affect egestion whereas both temperature and\\u000a sediment type had a significant influence. The worms egested less actively at the lowest temperature (6 °C). The egestion\\u000a rate, expressed as mg dry feces produced, was highest in the sandy sediment and lowest in the sediment derived almost exclusively\\u000a from decaying plant

Matti T. Leppänen; Jussi V. K. Kukkonen

1998-01-01

125

Individualised controlled ovarian stimulation (iCOS): maximising success rates for assisted reproductive technology patients  

Microsoft Academic Search

Background  In the last two decades, pregnancy rates for patients undergoing in-vitro fertilisation (IVF) have significantly increased.\\u000a Some of the major advances responsible for this improvement were the introduction of controlled ovarian stimulation (COS)\\u000a for the induction of multiple follicle development, and the utilisation of mid-luteal gonadotropin-releasing hormone agonists\\u000a to achieve pituitary down-regulation and full control of the cycle. As a

Ernesto Bosch; Diego Ezcurra

2011-01-01

126

Microstructural evolution in high strength materials at high strain rates  

Microsoft Academic Search

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

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

2006-01-01

127

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

128

Operation of high rate microstrip gas chambers  

NASA Astrophysics Data System (ADS)

We describe recent measurements carried out in well controlled and reproducible conditions to help understanding the factors affecting the short- and long-term behaviour of Microstrip Gas Chambers. Special care has been taken concerning the gas purity and choice of materials used in the system and for the detectors construction. Detectors built on glasses with surface resistivity in the range 10 13-10 15 ?/? have shown satisfactory performance as they do not show charging-up process at high rate and stand the large doses required for the future high luminosity experiments (˜10 mC-cm -1.yr -1). Concerning the lifetime measurements, it has been observed that chambers manufactured on high-resistivity glass are far more susceptible of suffering ageing than detectors made on low resistivity, electron-conducting supports, independently of the metal used for the artwork (chromium or gold) at least in clean gas conditions. The successfully operation in the laboratory of detectors manufactured on diamond-coated glass with a surface resistivity around 10 15 ?/? confirms the last statement. Results from a long-term, high rate beam test are also reported.

Barr, A.; Boimska, B.; Bouclier, R.; Capeáns, M.; Dominik, W.; Manzin, G.; Million, G.; Hoch, M.; Ropelewski, L.; Sauli, F.; Sharma, A.

1998-02-01

129

Operation of high rate microstrip gas chambers  

NASA Astrophysics Data System (ADS)

We describe recent measurements carried out in well controlled and reproducible conditions to help understanding the factors affecting the short- and long-term behaviour of Microstrip Gas Chambers. Special care has been taken concerning the gas purity and choice of materials used in the system and for the detectors construction. Detectors built on glasses with surface resistivity in the range 1013-1015 ?/? have shown satisfactory performance as they do not show charging-up process at high rate and stand the large doses required for the future high luminosity experiments (~10mCcm-1yr-1). Concerning the lifetime measurements, it has been observed that chambers manufactured on high-resistivity glass are far more susceptible of suffering ageing than detectors made on low resistivity, electron-conducting supports, independently of the metal used for the artwork (chromium or gold) at least in clean gas conditions. The successful operation in the laboratory of detectors manufactured on diamond-coated glass with a surface resistivity around 1015 ?/? confirms the last statement. Results from a long-term, high rate beam test are also reported.

Barr, A.; Boimska, B.; Bouclier, R.; Capeáns, M.; Dominik, W.; Manzin, G.; Million, G.; Hoch, M.; Ropelewski, L.; Sauli, F.; Sharma, A.

1997-02-01

130

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

131

High Strain Rate Behavior of Polyurea Compositions  

NASA Astrophysics Data System (ADS)

Polyurea has been gaining importance in recent years due to its impact resistance properties. The actual compositions of this viscoelastic material must be tailored for specific use. It is therefore imperative to study the effect of variations in composition on the properties of the material. High-strain-rate response of three polyurea compositions with varying molecular weights has been investigated using a Split Hopkinson Pressure Bar arrangement equipped with titanium bars. The polyurea compositions were synthesized from polyamines (Versalink, Air Products) with a multi-functional isocyanate (Isonate 143L, Dow Chemical). Amines with molecular weights of 1000, 650, and a blend of 250/1000 have been used in the current investigation. The materials have been tested up to strain rates of 6000/s. Results from these tests have shown interesting trends on the high rate behavior. While higher molecular weight composition show lower yield, they do not show dominant hardening behavior. On the other hand, the blend of 250/1000 show higher load bearing capability but lower strain hardening effects than the 600 and 1000 molecular weight amine based materials. Refinement in experimental methods and comparison of results using aluminum Split Hopkinson Bar is presented.

Joshi, Vasant; Milby, Christopher

2011-06-01

132

High strain rate behavior of polyurea compositions  

NASA Astrophysics Data System (ADS)

High-strain-rate response of three polyurea compositions with varying molecular weights has been investigated using a Split Hopkinson Pressure Bar arrangement equipped with aluminum bars. Three polyurea compositions were synthesized from polyamines (Versalink, Air Products) with a multi-functional isocyanate (Isonate 143L, Dow Chemical). Amines with molecular weights of 1000, 650, and a blend of 250/1000 have been used in the current investigation. These materials have been tested to strain rates of over 6000/s. High strain rate results from these tests have shown varying trends as a function of increasing strain. While higher molecular weight composition show lower yield, they do not show dominant hardening behavior at lower strain. On the other hand, the blend of 250/1000 show higher load bearing capability but lower strain hardening effects than the 600 and 1000 molecular weight amine based materials. Results indicate that the initial increase in the modulus of the blend of 250/1000 may lead to the loss of strain hardening characteristics as the material is compressed to 50% strain, compared to 1000 molecular weight amine based material.

Joshi, Vasant S.; Milby, Christopher

2012-03-01

133

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

134

Conception rate and reproductive function of dairy cows fed different fat sources.  

PubMed

The objective of the experiment was to determine the effects of fat supplementation on cyclicity, progesterone concentration, follicular development, conception rate, embryo mortality, and plasma concentrations of prostalglandin F metabolite (PGFM) in cattle. The hypothesis of this experiment was that feeding flaxseed, which is a source rich in C18:3, would increase conception rate of dairy cows due to decreased plasma PGFM concentrations. A total of 138 lactating Holstein cows were allotted at calving to three groups of 46 cows, blocked for similar calving dates. Cows within each block were assigned to one of three isonitrogenous, isoenergetic, and isolipidic supplements based on either whole flaxseed (FLA), Megalac (MEG) or micronized soybeans (SOY). The diets were fed from calving to Day 50 of pregnancy for pregnant cows, or 120 day postpartum for those not diagnosed pregnant after AI. Detailed measurements of PGFM and follicle dynamics were only made on four cows for FLA and five cows for both MEG and SOY. The response in PGFM concentration following the oxytocin challenge administered around Week 11 of lactation was similar over time among treatments. Plasma progesterone concentrations from Days 17 to 21 of the estrous cycle starting around Week 9 of lactation and determined on a subsample of cows (n=for FLA and n=5 for both MEG and SOY) were higher for cows fed FLA than for those fed SOY (P=0.04) or MEG (P=0.06). Conception rates were similar among treatments. Total embryo mortality was lower (P=0.07) for cows fed FLA (0%) compared to those fed either MEG (15.4%) or SOY (8.0%). The mean size of the CL measured during a complete estrous cycle from Week 9 of lactation was smaller for cows fed SOY (16.3 mm) compared to those fed either FLA (19.1 mm) or MEG (18.3 mm). We inferred that pregnancy losses could be reduced by feeding whole flaxseed as a result of its effects on different factors such as modulation in concentration of progesterone and size of the CL. PMID:16735061

Petit, H V; Twagiramungu, H

2006-09-15

135

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.

Battaile, Brian C.; Trites, Andrew W.

2013-01-01

136

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

137

High-energy, high-rate materials processing  

Microsoft Academic Search

The increasingly available range of pulsed-power, high energy kinetic storage devices, such as low-inductance pulse-forming networks, compulsators, and homopolar generators, is presently considered as a basis for industrial high energy\\/high rate (HEHR) processing to accomplish shock hardening, drilling, rapid surface alloying and melting, welding and cutting, transformation hardening, and cladding and surface melting in metallic materials. Time-temperature-transformation concepts furnish the

H. L. Marcus; D. L. Bourell; Z. Eliezer; C. Persad; W. Weldon

1987-01-01

138

Fuel droplet burning rates at high pressures.  

NASA Technical Reports Server (NTRS)

Combustion of methanol, ethanol, propanol-1, n-pentane, n-heptane, and n-decane was observed in air under natural convection conditions, at pressures up to 100 atm. The droplets were simulated by porous spheres, with diameters in the range from 0.63 to 1.90 cm. The pressure levels of the tests were high enough so that near-critical combustion was observed for methanol and ethanol. Due to the high pressures, the phase-equilibrium models of the analysis included both the conventional low-pressure approach as well as high-pressure versions, allowing for real gas effects and the solubility of combustion-product gases in the liquid phase. The burning-rate predictions of the various theories were similar, and in fair agreement with the data. The high-pressure theory gave the best prediction for the liquid-surface temperatures of ethanol and propanol-1 at high pressure. The experiments indicated the approach of critical burning conditions for methanol and ethanol at pressures on the order of 80 to 100 atm, which was in good agreement with the predictions of both the low- and high-pressure analysis.

Canada, G. S.; Faeth, G. M.

1973-01-01

139

Microalgal separation from high-rate ponds  

SciTech Connect

High rate ponding (HRP) processes are playing an increasing role in the treatment of organic wastewaters in sunbelt communities. Photosynthetic oxygenation by algae has proved to cost only one-seventh as much as mechanical aeration for activated sludge systems. During this study, an advanced HRP, which produces an effluent equivalent to tertiary treatment has been studied. It emphasizes not only waste oxidation but also algal separation and nutrient removal. This new system is herein called advanced tertiary high rate ponding (ATHRP). Phosphorus removal in HRP systems is normally low because algal uptake of phosphorus is about one percent of their 200-300 mg/L dry weights. Precipitation of calcium phosphates by autofluocculation also occurs in HRP at high pH levels, but it is generally not complete due to insufficient calcium concentration in the pond. In the case of Richmond where the studies were conducted, the sewage is very low in calcium. Therefore, enhancement of natural autoflocculation was studied by adding small amounts of lime to the pond. Through this simple procedure phosphorus and nitrogen removals were virtually complete justifying the terminology ATHRP.

Nurdogan, Y.

1988-01-01

140

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

141

High counting rate resistive-plate chamber  

SciTech Connect

Parallel-plate avalanche chambers (PPAC) are widely used in physics experiments because they are fast (<1 ns) and have very simple construction: just two parallel metallic plates or mesh electrodes. Depending on the applied voltage they may work either in spark mode or avalanche mode. The advantage of the spark mode of operation is a large signal amplitude from the chamber, the disadvantage is that there is a large dead time (msec) for the entire chamber after an event. The main advantage of the avalanche mode is high rate capability 10{sup 5} counts/mm{sup 2}. A resistive-plate chamber (RPC) is similar to the PPAC in construction except that one or both of the electrodes are made from high resistivity ({ge}10{sup 10} {Omega}{center_dot}cm) materials. In practice RPCs are usually used in the spark mode. Resistive electrodes are charged by sparks, locally reducing the actual electric field in the gap. The size of the charged surface is about 10 mm{sup 2}, leaving the rest of the detector unaffected. Therefore, the rate capability of such detectors in the spark mode is considerably higher than conventional spark counters. Among the different glasses tested the best results were obtained with electron type conductive glasses, which obey Ohm`s law. Most of the work with such glasses was done with high pressure parallel-plate chambers (10 atm) for time-of-flight measurements. Resistive glasses have been expensive and produced only in small quantities. Now resistive glasses are commercially available, although they are still expensive in small scale production. From the positive experience of different groups working with the resistive glasses, it was decided to review the old idea to use this glass for the RPC. This work has investigated the possibility of using the RPC at 1 atm and in the avalanche mode. This has several advantages: simplicity of construction, high rate capability, low voltage operation, and the ability to work with non-flammable gases.

Peskov, V.; Anderson, D.F.; Kwan, S.

1993-05-01

142

High counting rate resistive-plate chamber  

SciTech Connect

Parallel-plate avalanche chambers (PPAC) are widely used in physics experiments because they are fast (<1 ns) and have very simple construction: just two parallel metallic plates or mesh electrodes. Depending on the applied voltage they may work either in spark mode or avalanche mode. The advantage of the spark mode of operation is a large signal amplitude from the chamber, the disadvantage is that there is a large dead time (msec) for the entire chamber after an event. The main advantage of the avalanche mode is high rate capability 10[sup 5] counts/mm[sup 2]. A resistive-plate chamber (RPC) is similar to the PPAC in construction except that one or both of the electrodes are made from high resistivity ([ge]10[sup 10] [Omega][center dot]cm) materials. In practice RPCs are usually used in the spark mode. Resistive electrodes are charged by sparks, locally reducing the actual electric field in the gap. The size of the charged surface is about 10 mm[sup 2], leaving the rest of the detector unaffected. Therefore, the rate capability of such detectors in the spark mode is considerably higher than conventional spark counters. Among the different glasses tested the best results were obtained with electron type conductive glasses, which obey Ohm's law. Most of the work with such glasses was done with high pressure parallel-plate chambers (10 atm) for time-of-flight measurements. Resistive glasses have been expensive and produced only in small quantities. Now resistive glasses are commercially available, although they are still expensive in small scale production. From the positive experience of different groups working with the resistive glasses, it was decided to review the old idea to use this glass for the RPC. This work has investigated the possibility of using the RPC at 1 atm and in the avalanche mode. This has several advantages: simplicity of construction, high rate capability, low voltage operation, and the ability to work with non-flammable gases.

Peskov, V.; Anderson, D.F.; Kwan, S.

1993-05-01

143

A high data rate recorder for astronomy  

NASA Technical Reports Server (NTRS)

A magnetic tape recorder developed for the special requirements of radio astronomy and geodesy is described. These requirements include a high bit packing density and long record times. The current version of this longitudinal recorder used by the Very Long Baseline Array (VLBA) records 5.5 Terabits on a 14-in diameter reel of inch-wide tape. A maximum record rate of 256 Mb/s is achieved in the VLBA configuration with one recorder operating at 4 ms and utilizing 32 of the heads in a single stack. The VLBA recorders have been tested using a longitudinal density of 2.25 fr/micron; 448 data + 56 system tracks are recorded in 14 passes, each lasting 50 min, for a total record time (at 128 Mb/s) of 12 h on 14-in diameter reel of inch-wide 13-microns-thick D1-equivalent tape.

Hinteregger, H. F.; Rogers, A. E. E.; Cappallo, R. J.; Webber, J. C.; Petrachenko, W. T.

1991-01-01

144

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.

145

Reproductive physiology  

USGS Publications Warehouse

Conclusions: Although the general pattern of avian physiology applies to cranes, we have identified many physiological mechanisms (e.g., effects of disturbance) that need further study. Studies with cranes are expensive compared to those done with domestic fowl because of the crane's larger size, low reproductive rate, and delayed sexual maturity. To summarize, the crane reproductive system is composed of physiological and anatomical elements whose function is controlled by an integrated neural-endocrine system. Males generally produce semen at a younger age than when females lay eggs. Eggs are laid in clutches of two (1 to 3), and females will lay additional clutches if the preceding clutches are removed. Both sexes build nests and incubate the eggs. Molt begins during incubation and body molt may be completed annually in breeding pairs. However, remiges are replaced sequentially over 2 to 3 years, or abruptly every 2 to 3 years in other species. Most immature birds replace their juvenal remiges over a 2 to 3 year period. Stress interferes with reproduction in cranes by reducing egg production or terminating the reproductive effort. In other birds, stress elevates corticosterone levels and decreases LHRH release. We know little about the physiological response of cranes to stress.

Gee, G.F.; Russman, S.E.

1996-01-01

146

Factors Associated with the Reproductive Health Risk Behavior of High School Students in the Republic of the Marshall Islands  

ERIC Educational Resources Information Center

This study revealed factors associated with reproductive health risk behavior among high school students in the Republic of the Marshall Islands. The survey was conducted among high school students from grades 9 through 12 at 2 schools in Majuro, the capital of the Marshall Islands. The questions asked inquired about knowledge, attitude, and…

Suzuki, Keiko; Motohashi, Yutaka; Kaneko, Yoshihiro

2006-01-01

147

Neither vegetative nor reproductive advantages account for high frequency of male-steriles in southern Spanish gynodioecious Daphne laureola (Thymelaeaceae).  

PubMed

In gynodioecious species, male-steriles (termed "females" hereafter) usually exhibit some reproductive advantage over hermaphrodites that allow them to compensate for the loss of male reproductive function. This compensation can result from higher fecundity, vegetative outperformance, and/or lower inbreeding depression. In this study we compared vegetative and reproductive parameters of female and hermaphrodite Daphne laureola individuals in two southeastern Spanish populations and estimated the magnitude of inbreeding depression up to the seedling emergence stage by conducting controlled pollinations and experimental sowings of seed progenies in the field. Reproductive shrubs of both sexes did not differ significantly in size, leaf production, leaf size, leaf growth, nutrient allocation to leaves, and production of flowers and fruits. Seed set and seed size of cross- and self-pollinated flowers of hermaphrodites and cross-pollinated females were also similar. Seedling emergence rates of self- and cross-pollinated seeds from hermaphrodites under natural field conditions were similar, suggesting a minor role of inbreeding depression up to that reproductive stage. Seeds from females produced more seedlings than selfed seeds from hermaphrodites. In 21 populations surveyed in the study region over a broad geographical and elevational gradient, the proportion of females ranged between 20.6 and 56.1% and was inversely related to elevation. The establishment and maintenance of females in southeastern Spanish populations of D. laureola seem to be mainly mediated by ecological factors. PMID:11410465

Alonso, C; Herrera, C M

2001-06-01

148

High strain rate damage of Carrara marble  

Microsoft Academic Search

We made uniaxial tests on Carrara marble at strain rate at around 100\\/sTransition to pulverization is controlled by strain, not strain rateMarble is easy to pulverize, yet field observation of pulverized rocks is scarce

Mai-Linh Doan; Andrea Billi

2011-01-01

149

High metabolic rates in running birds  

Microsoft Academic Search

The ability to increase metabolic rate during locomotion has been important in the structural evolution and evolutionary success of both birds and mammals. Greater endurance capabilities are conferred directly by greater maximal metabolic rates, which vary between species. These maximal rates are known for many mammals but have not been determined for birds. We have measured oxygen consumption in a

Matthew W. Bundle; Hans Hoppeler; Ruth Vock; June M. Tester; Peter G. Weyand

1999-01-01

150

High-power, high-data-rate laser diode transmitter  

NASA Astrophysics Data System (ADS)

This paper reports the performance and test results of a high-power laser diode transmitter (HPLDT). The HPLDT provides a controlled environment to operate semiconductor lasers with power levels exceeding 0.5 W and is scalable to multi-watt output powers. It provides thermal and optical power control and overdrive protection, and is capable of modulating the laser at high data rates (up to 109 pulses/s). In addition, the HPLDT can accommodate a variety of semiconductor lasers and input modulating signal types over a wide bandwidth.

Ebben, Thomas H.; Begley, David L.; Marshalek, Robert G.

1995-03-01

151

Investigating the life-cycle and growth rate of Pediastrum boryanum and the implications for wastewater treatment high rate algal ponds.  

PubMed

The colonial alga Pediastrum boryanum has beneficial characteristics for wastewater treatment High Rate Algal Ponds (HRAP) including high biomass productivity and settleability. Our previous work has shown that these characteristics are enhanced when a portion of gravity harvested algae is recycled back to the pond. To help understand the mechanisms behind the improved performance of P. boryanum dominated HRAP with algal recycling, this study investigated the life-cycle of P. boryanum. Experiments determined the exact timing and growth rate of P. boryanum life-cycle stages ('juvenile', 'growth' and 'reproductive') under four combinations of light and temperature (250 or 120 ?Mol/m(2)/s; 20 or 10 °C). Single juvenile 16-celled colonies were grown in microcosms on an inverted microscope and photographed every 15 min until reproduction ceased. Two asexual life-cycles and a rarely occurring sexual life-cycle were observed. The time required to achieve asexual reproductive maturity increased from 52 h (high light and temperature) to 307 h (low light and temperature), indicating that the minimum hydraulic retention time or mean cell residence time (MCRT) must be higher than these values to sustain a P. boryanum HRAP culture under ambient conditions. The net growth rate of a P. boryanum colony varied between life-cycle stages (growth > juvenile > reproductive). This suggests that the higher biomass productivity measured in HRAP with algal recycling could be due to both the increased MCRT and an increase in the net growth rate of the HRAP culture by 'seeding' with faster growing colonies. PMID:24852411

Park, Jason B K; Craggs, Rupert J; Shilton, Andy N

2014-09-01

152

Highly comparative fetal heart rate analysis.  

PubMed

A database of fetal heart rate (FHR) time series measured from 7 221 patients during labor is analyzed with the aim of learning the types of features of these recordings that are informative of low cord pH. Our 'highly comparative' analysis involves extracting over 9 000 time-series analysis features from each FHR time series, including measures of autocorrelation, entropy, distribution, and various model fits. This diverse collection of features was developed in previous work [1]. We describe five features that most accurately classify a balanced training set of 59 'low pH' and 59 'normal pH' FHR recordings. We then describe five of the features with the strongest linear correlation to cord pH across the full dataset of FHR time series. The features identified in this work may be used as part of a system for guiding intervention during labor in future. This work successfully demonstrates the utility of comparing across a large, interdisciplinary literature on time-series analysis to automatically contribute new scientific results for specific biomedical signal processing challenges. PMID:23366590

Fulcher, B D; Georgieva, A E; Redman, C W G; Jones, N S

2012-01-01

153

In situ high rate growth of high temperature superconductor tapes  

SciTech Connect

In situ high rate growth of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconducting films has been carried out using e-beam deposition. A deposition flux controller is developed to monitor and control the deposition rates using tunable diode laser based atomic absorption. Wide range of temperatures, deposition rates, and oxygen fluxes including atomic and molecular oxygen, as well as ozone, have been explored in order to understand both kinetic and thermodynamic stability. Critical current density above 1 MA/cm{sup 2} has been achieved on SrTiO{sub 3} substrate samples in growth rate up to 75 {angstrom}/sec. Samples prepared on IBAD YSZ/Ni tapes exhibit similar R(T)s and x-ray diffraction patterns. However, critical current densities of the tapes are around kA/cm{sup 2} or lower. The poor critical current density of the tape is attributed to interaction between the YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} film and the YSZ buffer layer.

Hammond, M. R. B. (Malcom R. Beasley); Peng, L. S. (Luke S.); Wang, W. (Weizhi); Jo, W.; Ohnishi, T. (Tsuyoshi); Marshall, A. F. (Ann F.); Hammond, R. H. (Robert H.); Beasley, M. R. (Malcom R.); Peterson, E. J. (Eric J.); Ericson, R. (Richard)

2001-01-01

154

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

155

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...

156

High repetition rate femtosecond laser processing of metals  

Microsoft Academic Search

Previously, in high repetition rate femto second laser processing novel laser matter interacting effects were reported, such as heat accumulation and particle shielding. In this study, high repetition rate laser processing was investigated to discuss and understand the impact of laser repetition rate and accompanied accumulative laser material interacting effects. Therefore, a high repetition rate femto second fibre laser setup

Joerg Schille; Robby Ebert; Udo Loeschner; Patricia Scully; Nicholas Goddard; Horst Exner

2010-01-01

157

Burn Rates of Explosives at High Pressures.  

National Technical Information Service (NTIS)

The burn rates of PETN, HMX, PBX-9404, PBX-9501, and PBX-9502 in inert gases have been determined as a function of pressure to 340 MPa by a closed bomb technique. The burn rates were fit to the de St.-Robert equation R = aP/sup n/. An abrupt transition to...

J. A. Holy

1985-01-01

158

How endangered is sexual reproduction of high-mountain plants by summer frosts? Frost resistance, frequency of frost events and risk assessment.  

PubMed

In temperate-zone mountains, summer frosts usually occur during unpredictable cold spells with snow-falls. Earlier studies have shown that vegetative aboveground organs of most high-mountain plants tolerate extracellular ice in the active state. However, little is known about the impact of frost on reproductive development and reproductive success. In common plant species from the European Alps (Cerastium uniflorum, Loiseleuria procumbens, Ranunculus glacialis, Rhododendron ferrugineum, Saxifraga bryoides, S. moschata, S. caesia), differing in growth form, altitudinal distribution and phenology, frost resistance of reproductive and vegetative shoots was assessed in different reproductive stages. Intact plants were exposed to simulated night frosts between -2 and -14 °C in temperature-controlled freezers. Nucleation temperatures, freezing damage and subsequent reproductive success (fruit and seed set, seed germination) were determined. During all reproductive stages, reproductive shoots were significantly less frost resistant than vegetative shoots (mean difference for LT50 -4.2 ± 2.7 K). In most species, reproductive shoots were ice tolerant before bolting and during fruiting (mean LT50 -7 and -5.7 °C), but were ice sensitive during bolting and anthesis (mean LT50 around -4 °C). Only R. glacialis remained ice tolerant during all reproductive stages. Frost injury in reproductive shoots usually led to full fruit loss. Reproductive success of frost-treated but undamaged shoots did not differ significantly from control values. Assessing the frost damage risk on the basis of summer frost frequency and frost resistance shows that, in the alpine zone, low-statured species are rarely endangered as long as they are protected by snow. The situation is different in the subnival and nival zone, where frost-sensitive reproductive shoots may become frost damaged even when covered by snow. Unprotected individuals are at high risk of suffering from frost damage, particularly at higher elevations. It appears that ice tolerance in reproductive structures is an advantage but not an absolute precondition for colonizing high altitudes with frequent frost events. PMID:23386042

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

2013-03-01

159

PS foams at high pressure drop rates  

NASA Astrophysics Data System (ADS)

In this paper, we report data on PS foamed at 100 °C after CO2 saturation at 10 MPa in a new physical foaming batch that achieves pressure drop rates up to 120 MPa/s. Results show how average cell size of the foam nicely fit a linear behavior with the pressure drop rate in a double logarithmic plot. Furthermore, foam density initially decreases with the pressure drop rate, attaining a constant value at pressure drop rates higher than 40 MPa/s. Interestingly, furthermore, we observed that the shape of the pressure release curve has a large effect on the final foam morphology, as observed in tests in which the maximum pressure release rate was kept constant but the shape of the curve changed. These results allow for a fine tuning of the foam density and morphology for specific applications.

Tammaro, Daniele; De Maio, Attilio; Carbone, Maria Giovanna Pastore; Di Maio, Ernesto; Iannace, Salvatore

2014-05-01

160

Atlantic Puffin ( Fratercula arctica ) chick diet and reproductive performance at colonies with high and low capelin ( Mallotus villosus ) abundance  

Microsoft Academic Search

We compared nestling diet and growth, breeding phenology, breeding success, and adult mass of Atlantic Puffins (Fratercula arctica) between two seabird colonies adjacent to ocean habitat with presumed high and low cap- elin (Mallotus villosus) abundance in 1996-1998. We hypothesized that puffins at their colony at Gannet Islands, Labrador, where capelin were scarce, would exhibit lower reproductive performance than at

Shauna M. Baillie; Ian L. Jones

2003-01-01

161

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

162

Assisted Reproductive Technology Success Rates: National Summary and Fertility Clinic Reports. Volume 1. Eastern United States, 1995.  

National Technical Information Service (NTIS)

For many people who want to start a family, the dream of having a child is not easily realized: about 15% of American women have received some type of infertility service. Assisted reproductive technology (ART) has been used in the United States since 198...

1997-01-01

163

High dose rate transperineal interstitial brachytherapy for cervical cancer: high pelvic control and low complication rates  

Microsoft Academic Search

Purpose: To report the clinical outcome for cervical carcinoma treated with external beam pelvic radiotherapy and interstitial high dose rate (IS-HDR) brachytherapy.Methods and Materials: Between July 1991 and June 1996, 62 patients with locally advanced stage cervical carcinoma or early stage carcinoma that precluded satisfactory tandem and ovoid insertion were treated. Most patients received 36 Gy (range: 25 Gy–45 Gy)

D. Jeffrey Demanes; Rodney R Rodriguez; Dhananjay D Bendre; Thomas L Ewing

1999-01-01

164

Physiological Ecology of Moose: Nutritional Requirements for Reproduction with Respect to Body Condition Thresholds. Research Performance Report, 1 July 1998-30 June 1999. (Moose Research Center Report).  

National Technical Information Service (NTIS)

We conducted feeding trials with adult female moose (Alces alces) on high and low quality diets to assess the influence of nutrition and reproductive success on body condition and future reproduction. Although dry matter intake rates did not differ betwee...

T. R. Stephenson K. J. Hundertmark J. A. Crouse S. R. Rickabaugh

1999-01-01

165

Reproductive toxicity in rats with crystal nephropathy following high doses of oral melamine or cyanuric acid.  

PubMed

The industrial chemical melamine was used in 2007 and 2008 to raise the apparent protein content in pet feed and watered down milk, respectively. Because humans may be exposed to melamine via several different routes into the human diet as well as deliberate contamination, this study was designed to characterize the effect of high dose melamine or cyanuric acid oral exposure on the pregnant animal and developing fetus, including placental transfer. Clear rectangular crystals formed following a single triazine exposure which is a different morphology from the golden spherulites caused by combined exposure or the calculi formed when melamine combines with endogenous uric acid. Crystal nephropathy, regardless of cause, induces renal failure which in turn has reproductive sequelae. Specifically, melamine alone-treated dams had increased numbers of early and late fetal deaths compared to controls or cyanuric acid-treated dams. As melamine was found in the amniotic fluid, this study confirms transfer of melamine from mammalian mother to fetus and our study provides evidence that cyanuric acid also appears in the amniotic fluid if mothers are exposed to high doses. PMID:24582682

Stine, Cynthia B; Reimschuessel, Renate; Keltner, Zachary; Nochetto, Cristina B; Black, Thomas; Olejnik, Nicholas; Scott, Michael; Bandele, Omari; Nemser, Sarah M; Tkachenko, Andriy; Evans, Eric R; Crosby, Tina C; Ceric, Olgica; Ferguson, Martine; Yakes, Betsy J; Sprando, Robert

2014-06-01

166

Simulation of reproductive rate, prey selection and the survival of pelagic fish of the African Great Lakes  

Microsoft Academic Search

Populations of two prey groups of pelagic mainly zooplanktivorous fish with differing life history strategies, were simulated with a Lotka-Volterra model with predation. Group r fish are r-selected species and have a high rate of biomass increase. These comprise of the small pelagic cyprinids of Lakes Malawi and Victoria and the clupeids of Lake Tanganyika. Group K fish are K-selected

A. B. Thompson

1999-01-01

167

Controlling the high order multiple birth rate: the European perspective.  

PubMed

The dramatic increase in the incidence of high order multiple pregnancies that has occurred since the mid-1970s is due to three main factors: increasing female age at conception; increasing use of ovulation induction agents and the introduction of sophisticated assisted reproduction techniques. High order multiple pregnancies are at significantly higher risk of complications than singleton pregnancies, for the fetuses, babies and the mothers. The aim of all fertility treatments is to achieve a healthy live child for each couple seeking treatment. Treatment of infertility by IVF and related techniques provides an ideal opportunity to limit the number of high order multiple pregnancies by reducing the number of embryos transferred to the woman. The realization that high order multiple pregnancy can and should be avoided has increasingly led, in most European countries, to a restriction of the number of embryos for transfer to two or even one, without a significant decrease in a couples' chance of achieving a pregnancy. The experience of European countries in reducing the number of embryos transferred is reviewed and a recommendation made that a responsible attitude to embryo transfer is adopted by all practitioners of assisted reproduction. PMID:12735870

Brinsden, Peter R

2003-01-01

168

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.

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

2010-01-01

169

High counting rate resistive-plate chamber  

SciTech Connect

Resistive-glass, parallel-plate chambers are studied in both spark and avalanche modes. In the avalanche mode rates of over 10{sup 3}s{sup {minus}1}cm{sup {minus}2} are achievable with a total collected charges per pulse of 10{sup 8} electrons. Operated at low pressure and with secondary-electron emission from a porous CsI surface, a timing resolution of 600 ps has been measured. Future improvements are discussed.

Anderson, D.F.; Kwan, S.; Peskov, V.

1993-08-01

170

Cuckoldry rates in the Molly Miller ( scartella cristata ; blenniidae), a hole-nesting marine fish with alternative reproductive tactics  

Microsoft Academic Search

Microsatellite markers were developed and employed to assess genetic maternity and paternity of embryos in nest-tended clutches of the Molly Miller (Scartella cristata), a marine fish in which alternative reproductive tactics (ARTs) by males were recently described from behavioral and morphological evidence. Genetic data gathered for 1,536 surveyed progeny, from 23 barnacle-nest holes in a single Floridian population, indicate that

Mark Mackiewicz; Brady A. Porter; Elizabeth E. Dakin; John C. Avise

2005-01-01

171

Reproductive soundness is higher in chickens selected for low as compared with high antibody response.  

PubMed

White Leghorn chickens were selected for 36 generations for high (HAS) or low (LAS) antibody response to SRBC 5 d after an intravenous challenge. The aim of this study was to investigate possible changes in reproductive soundness resulting from that selection. Age and BW at onset of lay (first egg), along with weight of the first egg, were recorded on 45 hens from each line. Intensity of lay was measured as the number of ovulations within a 15-d period over 15 sequential intervals (total 225 d). Three cycles of fertility also were assessed, coinciding with early, middle, and late production stages. For fertility of males and females within a line to be independently evaluated, roosters and hens were mated by artificial insemination to an unrelated control line of White Plymouth Rocks. Twenty roosters from each antibody line were considered, as well as the 45 hens. Pooled semen from the control line was used for mating the hens from the antibody lines. Hens from the LAS line commenced lay at a younger age (11.67±3.53 d; P<0.001), lighter BW (-169.46±40.20 g; P<0.001), and with greater intensity (2.68±0.25%; P=0.001) than those from the HAS line. Any differences in intensity thereafter were trivial between lines (P=0.42), with intensity decreasing sharply toward the end of the 7-mo production period in both lines. Length of fertility differed between hens of the antibody lines during the first cycle (3.35±0.85 d; P=0.002) and between roosters during the first (3.58±1.06 d; P=0.02) and second (3.38±1.07 d; P=0.03) cycles, with chickens from the LAS line having the longer length of fertility in both sexes. A correlated response in reproductive soundness to divergent selection for antibody response was observed. This may in part be due to differences in resource allocations, with particular impact on duration of fertility. PMID:22802170

Albrecht, H N; Siegel, P B; Pierson, F W; McGilliard, M L; Lewis, R M

2012-08-01

172

Development of Korean Academy of Medical Sciences Guideline rating the physical impairment; kidney, bladder, urethra, male and female reproductive systems (preliminary report).  

PubMed

For the evaluation of the kidney impairment, serum creatinine concentrations or glomerular filtration rates are mainly used, and the conditions of solitary or transplanted kidney and chronic dialysis are also taken into the considerations. Some symptoms and signs of the chronic renal disability in spite of adequate treatment add one additional grade. For evaluating bladder and urethral impairment, the criteria include voiding symptoms and signs. The patients with urinary diversions have impairment grades depending on the alteration of upper urinary tract function. For penile impairment, the degrees are evaluated using the international index of erectile function, nocturnal penile tumescence and color doppler ultrasonography. For evaluating impairment of other male reproductive organs, functional and anatomical changes of these organs, analysis of the semen or hormones and the state of solitary testis are used as the criteria. For evaluating impairment of female reproductive organs, pregnancy potential, requirement of continuous treatment and the ability of sexual intercourse are used. Also, degree of impairment is modified according to the ages in evaluating female reproductive systems. We have tried to make this evaluation system objective, scientific, and convenient, but still find it leaving much to be desired. PMID:19503685

Yu, Ji Hyeong; Kim, Sang Hyun; Sohn, Seung Hwan; Paik, Kyung Hoon; Lee, Jeong Zoo; Kim, Jang Hwan; Park, Jong Kwan; Ryu, Ki-Sung; Jun, Jong Kwan; Cho, Yong Kyoon; Chung, Jae Yong

2009-05-01

173

Effects of high-dose soy isoflavones and equol on reproductive tissues in female cynomolgus monkeys.  

PubMed

Soy isoflavonoids have well-established estrogenic properties in cell culture and rodent models, raising concerns that high isoflavonoid intake may promote development of uterine and breast cancers. To address this concern we evaluated the effects of high-dose isoflavonoid supplements on reproductive tissues in a postmenopausal primate model. Thirty adult female ovariectomized monkeys (Macaca fascicularis) were randomized to receive a control diet 1) alone, 2) with 509 mg/day of the soy isoflavones genistein and daidzein (IF), or 3) with 1020 mg/day of racemic equol (EQ), an isoflavan, for approximately 1 mo. Doses are expressed in aglycone units as calorically scaled human equivalents. Total serum isoflavonoid levels 4 h postfeeding were <20 nmol/L, 2570.7 nmol/L, and 6944.8 nmol/L for control, IF, and EQ groups, respectively. Equol was the predominant serum isoflavonoid in both IF (72.5%) and EQ (99.7%) groups. Aglycones represented 0.9% (IF) and 0.5% (EQ) of total serum isoflavonoids. Histologically, uteri and mammary glands were diffusely atrophic in all groups. Uterine weight, endometrial thickness, glandular area, and epithelial proliferation in the uterus were not significantly different among treatment groups (ANOVA P > 0.1 for all). Endometrial progesterone receptor gene expression was significantly increased in the IF group (P = 0.02), while protein expression was not altered (ANOVA P > 0.1). Within the mammary gland, proliferation and indicators of estrogen exposure did not differ among treatment groups (ANOVA P > 0.1 for all). These findings indicate that high doses of dietary soy isoflavonoids have minimal uterotrophic or mammotrophic effects in an established primate model. PMID:16723506

Wood, Charles E; Appt, Susan E; Clarkson, Thomas B; Franke, Adrian A; Lees, Cynthia J; Doerge, Daniel R; Cline, J Mark

2006-09-01

174

High summer temperatures affect the survival and reproduction of olive fruit fly (Diptera: Tephritidae).  

PubMed

The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is an invasive pest in California. Identifying environmental constraints that affect the geographic distribution and abundance of any invasive insect pest is fundamental to its effective management. California's Central Valley, where most commercial olives are grown, is extremely hot during the summer, with maximum daily temperatures consistently >35.0 degrees C. This study examined the effects of two diurnal temperature regimens (low 18.3 degrees C, high 35.0 or 37.8 degrees C) reflecting summer conditions in the valley, and one control temperature regimen (low 18.3 degrees C, high 23.9 degrees C) on the fly's survival and reproductive success in the laboratory. The temperature regimen of 18.3-35.0 degrees C resulted in delayed egg maturation and reduced production of mature eggs compared with the control temperature regimen. Egg maturation was possible at the higher temperature regimen when females were provided with water and food, and egg-laying occurred during the cold phase of the temperature cycle. Access to olive fruit and oviposition itself further promoted egg maturation. Under exposure to the 18.3-35.0 degrees C temperature regimen, approximately 50% of eggs died, and the remainder that hatched died as first instars. No egg hatch occurred at the temperature treatment of 18.3-37.8 degrees C. We confirmed these laboratory results through field cage studies with adult B. oleae, conducted in the summer of 2007 and 2008. Under ambient summer temperatures, adult B. oleae survived for 1-2 wk, and females readily laid eggs when provided water and food. No offspring developed in midsummer of 2007, and <2% of the offspring developed to adults in summer 2008 trials. These results suggest that high summer temperatures limit the fly's abundance in California's Central Valley. PMID:19825305

Wang, Xin-Geng; Johnson, Marshall W; Daane, Kent M; Nadel, Hannah

2009-10-01

175

Effect of intermittent hypoxia on the reproduction of rats exposed to high altitude in the Chilean Altiplano.  

PubMed

Environmental parameters such as the large day-night temperature differences, high light radiation, and low humidity may have a synergistic effect with low oxygen pressure. To evaluate the effects of the exposure to intermittent chronic hypobaric hypoxia (ICHH) in nature on rat reproduction, a group of rats was alternately moved to a location at 3400 meters over sea level (moml) for 7 days and returned the subsequent week to sea level; this procedure was repeated six times. Hematological and reproductive parameters were measured and analyzed. At the end of the experimental protocol, hematocrit and hemoglobin concentrations were significantly greater in the ICHH group compared to the control group (Nx) (p < 0.05). The diameter of the seminiferous tubule and the height of the spermatogenic epithelium in ICHH rats presented a significant decrease in relation to Nx rats (p < 0.05). Consequently, the number of epididymal spermatozoa in the experimental animals decreased compared to normal rats, with no evidence of recovery after 84 days. The offspring of the different matings between normal and hypoxic animals decreased proportionally to hypoxia exposure. The low oxygen and the changes in testicular temperature homeostasis would provide a novel local mechanism to explain the decrease in sperm cell production and the reduced number of puppies born. The alterations of the reproductive parameters of the hypoxic female, plus testicular injuries and diminished sperm in males, result in a significant decrease in the reproductive activity of the animals. PMID:20039817

Cikutovic, Marcos; Fuentes, Nelson; Bustos-Obregón, Eduardo

2009-01-01

176

High Lifetime Pregnancy and Low Contraceptive Usage Among Sex Workers Who Use Drugs- An Unmet Reproductive Health Need  

PubMed Central

Background The objective of this study was to describe levels of pregnancy and contraceptive usage among a cohort of street-based female sex workers (FSWs) in Vancouver. Methods The study sample was obtained from a community-based prospective cohort study (2006-2008) of 211 women in street-based sex work who use drugs, 176 of whom had reported at least one prior pregnancy. Descriptive statistics were used to estimate lifetime pregnancy prevalence, pregnancy outcomes (miscarriage, abortion, adoption, child apprehension, child custody), and contraceptive usage. In secondary analyses, associations between contraceptive usage, individual and interpersonal risk factors and high number of lifetime pregnancies (defined as greater than the sample mean of 4) were examined. Results Among our sample, 84% reported a prior pregnancy, with a mean of 4 lifetime pregnancies (median = 3; IQR: 2-5). The median age of women reporting 5+ pregnancies was 38 years old [interquartile range (IQR): 25.0-39.0] compared to 34 years [IQR: 25.0-39.0] among women reporting 4 or fewer prior pregnancies. 45% were Caucasian and 47% were of Aboriginal ancestry. We observed high rates of previous abortion (median = 1;IQR:1-3), apprehension (median = 2; IQR:1-4) and adoption (median = 1; IQR:1-2) among FSWs who reported prior pregnancy. The use of hormonal and insertive contraceptives was limited. In bivariate analysis, tubal ligation (OR = 2.49; [95%CI = 1.14-5.45]), and permanent contraceptives (e.g., tubal ligation and hysterectomy) (OR = 2.76; [95%CI = 1.36-5.59]) were both significantly associated with having five or more pregnancies. Conclusion These findings demonstrate high levels of unwanted pregnancy in the context of low utilization of effective contraceptives and suggest a need to improve the accessibility and utilization of reproductive health services, including family planning, which are appropriately targeted and tailored for FSWs in Vancouver.

2011-01-01

177

Star high rate link model: Clock regeneration  

NASA Astrophysics Data System (ADS)

The receiving part of this module, used in spacecraft transmission through a relay satellite, requires a very accurate clock reference in the extraction of data from a QPSK modulated signal at a bit rate of 100 MHz. The results achieved to improve this accuracy working on the nonlinear treatment and the narrow band filtering are described. The chosen clock detector is based on a delay line and a multiplier. The multiplication is assured in ECL logic by an exclusive or. The filter is based on a narrow band phase loop. It is shown that the performance degradation introduced by the clock regenerator is 0.2 dB if the static phase error is kept within 5 deg.

Soldermann, J. P.; Grondin, M.

1984-11-01

178

High reproduction of Calanus finmarchicus during a diatom-dominated spring bloom  

Microsoft Academic Search

Feeding, egg production, hatching success and early naupliar development of Calanus finmarchicus were measured in three north Norwegian fjords during a spring bloom dominated by diatoms and the haptophyte Phaeocystis pouchetii. Majority of the copepod diet consisted of diatoms, mainly Thalassiosira spp. and Chaetoceros spp., with clearance rates up to 10 ml ind?1 h?1 for individual algae species\\/groups. Egg production rates were high,

Marja Koski

2007-01-01

179

Consideration of wear rates at high velocity  

Microsoft Academic Search

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.

Chad S. Hale

2010-01-01

180

High fat diet affects reproductive functions in female diet-induced obese and dietary resistant rats.  

PubMed

The incidence of ovulatory disorders is common in obese animal models. The mechanism behind this effect is unclear. We hypothesised that a high-fat (HF) diet induces alterations in neuroendocrine mechanisms resulting in anovulation in diet-induced obese (DIO) animals. Adult female DIO and diet-resistant (DR) rats were fed either chow or a HF diet (45% calories from fat) for 6 weeks. Oestrous cyclicity and body weight were monitored regularly. At the end of treatment, rats were implanted with a jugular catheter to monitor luteinising hormone (LH) levels on the day of pro-oestrous. Rats were sacrificed on the next pro-oestrous, and their brains and ovaries were collected. Plasma from trunk blood was analysed for oestradiol and leptin concentrations. Ovaries were fixed and sectioned for histological analysis. Brains were removed, frozen and sectioned, and norepinephrine (NE) concentrations in discrete hypothalamic areas were measured using high-performance liquid chromatography with electrochemical detection. A HF diet exposure affected oestrous cyclicity in both DIO and DR rats, with the effect being more pronounced in DIO animals. HF diet exposure increased leptin levels in both DIO and DR rats. Oestradiol levels were low in the DIO-HF group. NE levels in the hypothalamus were unaffected by HF diet or genotype. A normal LH surge was observed in DR-Chow rats and LH levels were low in the remaining groups. These results lead to the conclusion that DIO rats have an inherently reduced reproductive capacity and exposure to a HF diet decreases it further. A reduction in oestradiol and LH surge levels could contribute to this effect; however, the underlying mechanisms need to be investigated further. PMID:22192683

Balasubramanian, P; Jagannathan, L; Mahaley, Rochell E; Subramanian, M; Gilbreath, E T; Mohankumar, P S; Mohankumar, S M J

2012-05-01

181

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

182

Self-mixing laser Doppler vibrometry with high optical sensitivity: application to real-time sound reproduction  

Microsoft Academic Search

Nanometre vibration measurement of an audio speaker and a highly sensitive sound reproduction experiment have been successfully demonstrated by a self-aligned optical feedback vibrometry technique using the self-mixing modulation effect in a laser-diode-pumped microchip solid-state laser. By applying nanometre vibrations to the speaker, which produced nearly inaudible music below 20 dB (200 µPa) sound pressure level, we could reproduce clear

Kazutaka Abe; Kenju Otsuka; Jing-Yuan Ko

2003-01-01

183

The modern high rate digital cassette recorder  

NASA Technical Reports Server (NTRS)

The magnetic tape recorder has played an essential role in the capture and storage of instrumentation data for more than thirty years. During this time, data recording technology has steadily progressed to meet user demands for more channels, wider bandwidths, and longer recording durations. When acquisition and processing moved from analog to digital techniques, so recorder design followed suit. Milestones marking the evolution of the data recorder through these various stages - multi-track analog, high density longitudinal digital, and more recently rotary digital - have often represented important breakthroughs in the handling of ever-greater quantities of data. Throughout this period there has been a very clear line of demarcation between data storage methods in the 'instrumentation world' on the one hand and the 'computer peripheral world' on the other. This is despite the fact that instrumentation data, whether analog or digital at the point of acquisition, is now likely to be processed on a digital computer at some stage. Regardless of whether the processing device is a small personal computer, a workstation, or the largest supercomputer, system integrators have traditionally been faced with the same basic problem - how to interface what is essentially a manually controlled, continuously running device (the tape recorder) into the fast start/stop computer environment without resorting to an excessive amount of complex custom interfacing and performance compromise. The increasing availability of affordable high power processing equipment throughout the scientific world is forcing recorder manufacturers to make their latest and perhaps most important breakthrough - the computer-friendly data recorder. The operating characteristics of such recorders are discussed and the resultant impact on both data acquisition and data analysis elements of system configuration are considered.

Clemow, Martin

1993-01-01

184

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

185

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

186

Strain rate dependence of twinning avalanches at high speed impact  

NASA Astrophysics Data System (ADS)

The molecular dynamics simulation of the yield collapse in ferroelastic and martensitic materials under high strain rates shows power law decays of the yield energy. The energy exponent of the "jerk" distribution during yield does not depend on the strain rate and was found to be close to the mean field value of ? = 1.35. The total yield energy changes dramatically during the crossover between the isothermal regime at low strain rates and the adiabatic regime at high strain rates. The crossover point is found in our simulations at 10-5/phonon time which corresponds to strain rates of approximately 108 1/s. Faster strain rates occur for high speed impact (shock deformation) with no strain absorption by twinning and no thermal equilibration while slightly slower strain rates lead to rate independent yield energies.

Zhang, L.; Salje, E. K. H.; Ding, X.; Sun, J.

2014-04-01

187

Global crop exposure to critical high temperatures in the reproductive period: historical trends and future projections  

NASA Astrophysics Data System (ADS)

Long-term warming trends across the globe have shifted the distribution of temperature variability, such that what was once classified as extreme heat relative to local mean conditions has become more common. This is also true for agricultural regions, where exposure to extreme heat, particularly during key growth phases such as the reproductive period, can severely damage crop production in ways that are not captured by most crop models. Here, we analyze exposure of crops to physiologically critical temperatures in the reproductive stage (Tcrit), across the global harvested areas of maize, rice, soybean and wheat. Trends for the 1980-2011 period show a relatively weak correspondence (r = 0.19) between mean growing season temperature and Tcrit exposure trends, emphasizing the importance of separate analyses for Tcrit. Increasing Tcrit exposure in the past few decades is apparent for wheat in Central and South Asia and South America, and for maize in many diverse locations across the globe. Maize had the highest percentage (15%) of global harvested area exposed to at least five reproductive days over Tcrit in the 2000s, although this value is somewhat sensitive to the exact temperature used for the threshold. While there was relatively little sustained exposure to reproductive days over Tcrit for the other crops in the past few decades, all show increases with future warming. Using projections from climate models we estimate that by the 2030s, 31, 16, and 11% respectively of maize, rice, and wheat global harvested area will be exposed to at least five reproductive days over Tcrit in a typical year, with soybean much less affected. Both maize and rice exhibit non-linear increases with time, with total area exposed for rice projected to grow from 8% in the 2000s to 27% by the 2050s, and maize from 15 to 44% over the same period. While faster development should lead to earlier flowering, which would reduce reproductive extreme heat exposure for wheat on a global basis, this would have little impact for the other crops. Therefore, regardless of the impact of other global change factors (such as increasing atmospheric CO2), reproductive extreme heat exposure will pose risks for global crop production without adaptive measures such as changes in sowing dates, crop and variety switching, expansion of irrigation, and agricultural expansion into cooler areas.

Gourdji, Sharon M.; Sibley, Adam M.; Lobell, David B.

2013-06-01

188

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 ...

189

Effects of Chemotherapeutic Agents for Testicular Cancer on the Male Rat Reproductive System, Spermatozoa, and Fertility  

Microsoft Academic Search

Testicular cancer is the most common cancer affect- ing men of reproductive age. Advances in treatment of the disease, which include the coadministration of bleomycin, etoposide, and cis- platinum (BEP), have brought the cure rate to over 90%. This high cure rate, coupled with the young age of patients, makes elucidation of the impact of the treatment on reproductive function,

ADRIENNE M. BIEBER; LUDOVIC MARCON; BARBARA F. HALES; BERNARD ROBAIRE

2006-01-01

190

Experimentally simulating high-rate behaviour: rate and temperature effects in polycarbonate and PMMA.  

PubMed

This paper presents results from applying a recently developed technique for experimentally simulating the high-rate deformation response of polymers. The technique, which uses low strain rate experiments with temperature profiles to replicate high-rate behaviour, is here applied to two amorphous polymers, polymethylmethacrylate (PMMA) and polycarbonate, thereby complementing previously obtained data from plasticized polyvinyl chloride. The paper presents comparisons of the mechanical data obtained in the simulation, as opposed to those observed under high-rate loading. Discussion of these data, and the temperature profile required to produce them, gives important information about yield and post-yield behaviour in these materials. PMID:24711491

Kendall, M J; Siviour, C R

2014-01-01

191

The Ewe's Reproductive Performance, Growth Rate and Carcass Quality of Lambs Kept in a Barn vs Those Kept under an Overhead Shelter  

PubMed Central

A herd of polish lowland local sheep was divided into two equal groups: the first group was kept under an overhead shelter, and the second group was kept in a warm barn. The effect of maintenance on ewe’s reproductive performance, survival as well as the growth rate of lambs, and their carcasses quality was investigated. The lack of differences in fertility and prolificacy of ewes as well as in the survival and growth rate between the groups confirmed a good adaptation of ?ela?nie?ska sheep to low temperature. Harsh environmental conditions did not cause a significant decrease of the body weight growth; however, they brought in an (insignificant) reduction of subcutaneous fat thickness and meatiness of the loin part of a lamb’s body. The fat content of carcasses obtained from lambs reared under the overhead shelter was significantly lower, with no differences of meat and bones contribution between the groups.

Kuznicka, Ewa; Rant, Witold

2013-01-01

192

Animal Reproduction  

NSDL National Science Digital Library

From Dr. Michael Gregory of Clinton Community College, this site is a concise overview of animal reproduction. The site addresses important aspects of sexual and asexual reproduction, the male and female reproductive systems, fertilization, and the importance of hormones. Visitors to the site will find diagrams outlining biological processes especially helpful.

Gregory, Michael

2007-12-14

193

ADONIS : a new system for high count rate HPGe ? spectrometry  

Microsoft Academic Search

The ADONIS (Algorithmic Development framewOrk for Nuclear Instrumentation and Spectrometry) system is a new ? spectrometer which addresses high count rate metrology. It has been developed for count rate up to 106 cps and beyond on HPGe detectors. The ADONIS system has been designed in order to: (1) maximize the (pile-up free) output count rate (OCR), (2) achieve both qualitative

Eric Barat; Thomas Dautremer; L. Laribiere; J. Lefevre; T. Montagu; J.-C. Trama

2006-01-01

194

Aminopeptidase activity in seminal plasma and effect of dilution rate on rabbit reproductive performance after insemination with an extender supplemented with buserelin acetate.  

PubMed

Ovulation induction in artificially inseminated rabbits by adding GnRH synthetic analogues in the seminal doses is a welfare-orientated method to induce ovulation in rabbits and could have some advantages in field practice. This study was conducted to determine the effect of male genotype on the aminopeptidase activity in rabbit seminal plasma and the effects of dilution rate of semen on availability and reproductive performance when buserelin acetate is added to the seminal dose. To study the aminopeptidase activity, 12 mature bucks belonging to a paternal line and 12 from a maternal line were used. The bucks from the paternal line were used to study the effect of dilution rate on the availability of buserelin acetate after 2 hours of dilution and on the reproductive performance of the doses after artificial insemination of 389 commercial crossbreed does. Aminopeptidase activity in seminal plasma is dependent on the male genotype. The paternal line resulted 27% more aminopeptidase activity than the maternal line (P < 0.05). On the other hand, semen diluted 1:20 exhibited a marked increase in the availability of buserelin acetate and the fertility in this group was significantly higher than females from dilution rate 1:5 group, which showed similar results to that of the negative control group (does inseminated with semen diluted 1:20 in non-GnRH-supplemented extender). We conclude that the bioavailability of buserelin acetate when added to the seminal dose appears to be determined by the activity of the existing aminopeptidases and is consequently affected by the dilution rate used to prepare the artificial insemination doses. PMID:24629591

Viudes-de-Castro, M P; Mocé, E; Lavara, R; Marco-Jiménez, F; Vicente, J S

2014-06-01

195

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

196

Reproductive Effects in F1 Adult Females Exposed In Utero to Moderate to High Doses of Mono-2-ethylhexylphthalate (MEHP)  

PubMed Central

Phthalates are widely used as plasticizers in everyday products. Yet, studies on the effects of phthalates on female reproductive health are limited. In this study, pregnant C57/Bl6 mice were exposed via oral gavage to corn oil, 100, 500, or 1000mg/kg MEHP from gestational days 17–19. Reproductive lifespan was decreased by one month in the highest F1 exposure group (9.8±0.4 versus 11.1±0.6 months in control F1 females). F1 females exhibited delayed estrous onset at the two higher exposures and prolonged estrus was observed in all MEHP-exposed females. Serum FSH and estradiol were significantly elevated at the highest exposure and altered mRNA expression was found for the steroidogenic genes LHCGR, aromatase, and StAR. At one year of age, mammary gland hyperplasia was observed in high dose MEHP-exposed females. In summary, late gestational exposure to MEHP leads to multiple latent reproductive effects throughout murine life resulting in premature ovarian senescence and mammary hyperplasia.

Moyer, Benjamin; Hixon, Mary L.

2012-01-01

197

Integrating high-rate DAF technology into plant design  

Microsoft Academic Search

Compared with sedimentation, dissolved-air flotation (DAF) is a more efficient clarification process for separating floc particles, which are often low in density. This article investigates the use of short flocculation times with high DAF and filter hydraulic loading rates and examines the feasibility of integrating high-rate DAF technology into water facility design. Research was conducted at pilot scale using two

James K. Edzwald; John E. Tobiason; Tony Amato; Lawrence J. Maggi

1999-01-01

198

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

199

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 )...

200

High counting rate, two-dimensional position sensitive timing RPC  

NASA Astrophysics Data System (ADS)

Motivated by the requirements of the next generation experiments in terms of very good time and position resolution in high counting rate and multiplicity environment, a new architecture of differential, strip structure, symmetric, multi gap timing RPC was developed. The results on efficiency, time resolution, position resolution and performance in high counting rate environment using low resistivity glass electrodes are reported.

Petrovici, M.; Petri?, M.; Simion, V.; Barto?, D.; Caragheorgheopol, G.; Constantin, F.; R?dulescu, L.; Adamczewski-Musch, J.; Deppner, I.; Doroud, K.; Herrmann, N.; Linev, S.; Loizeau, P.; Williams, M. C. S.

2012-11-01

201

Motion Artifacts of Extended High Frame Rate Imaging  

Microsoft Academic Search

Based on the high frame rate (HFR) imaging method developed in our lab, an extended high frame rate imaging method with various transmission schemes was developed recently. In this method, multiple, limited- diffraction array beams or steered plane wave transmissions are used to increase image resolution and field of view as well as to reduce sidelobes. Furthermore, the multiple, limited-diffraction

Wang Jing; Lu Jian-yu

2007-01-01

202

High-mass star-formation rates in M33  

Microsoft Academic Search

The H I, CO, and H-alpha data for M33 are analyzed to obtain high-mass star formation rates and efficiencies and to look for variations in these quantities within the inner disk of M33. Star formation rates and efficiencies are calculated using calibrated H-alpha data. The H-alpha emission in this region of the galaxy corresponds to high-mass and total star-formation rates

Christine D. Wilson; Nick Scoville; Walter Rice

1991-01-01

203

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

204

The status of low dose rate and future of high dose rate Cf252 brachytherapy  

Microsoft Academic Search

This work describes the current status of the US low dose rate (LDR) Cf-252 brachytherapy program. The efforts undertaken towards development of a high dose rate (HDR) remotely after loaded Cf-252 source, which can accommodate 1 mg or greater Cf-252, are also described. This HDR effort is a collaboration between Oak Ridge National Laboratory (ORNL), commercial remote after loader manufactures,

M. J. Rivard; J. G. Wierzbicki; F. Van den Heuvel; P. J. Chuba; J. Fontanesi; R. C. Martin; R. R. McMahon; R. G. Haire

1997-01-01

205

Processing of high-temperature superconductors at high strain rates  

Microsoft Academic Search

This new book provides, for the first time, a systematic, unified presentation of all steps in the processing of high-temperature superconductor materials, ranging from synthesis of various systems to fabrication and industrial applications. Also covered are characterization techniques and current directions in research and development. The authors are leading specialists who bring to this new book their many years of

A. G. Mamalis; G. Pantazsopoulos; D. E. Manolakos; A. Szalay

2000-01-01

206

High data-rate atom interferometer for measuring acceleration  

SciTech Connect

We demonstrate a high data-rate light-pulse atom interferometer for measuring acceleration. The device is optimized to operate at rates between 50 Hz to 330 Hz with sensitivities of 0.57{mu}g/{radical}(Hz) to 36.7{mu}g/{radical}(Hz), respectively. Our method offers a dramatic increase in data rate and demonstrates a path to applications in highly dynamic environments. The performance of the device can largely be attributed to the high recapture efficiency of atoms from one interferometer measurement cycle to another.

McGuinness, Hayden J. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Rakholia, Akash V.; Biedermann, Grant W. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Center for Quantum Information and Control (CQuIC), Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico, 87131 (United States)

2012-01-02

207

High variance in reproductive success of the Pacific oyster ( Crassostrea gigas, Thunberg) revealed by microsatellite-based parentage analysis of multifactorial crosses  

Microsoft Academic Search

Marine bivalves are known to have small Ne\\/N ratios, both in wild and hatchery-propagated populations. This has been interpreted as the consequence of a high variance in reproductive success. However, how much of this variance could be attributed to pre-zygotic reproductive factors or to post-zygotic selection was not yet estimated. To estimate the relative effect of these factors, we have

P Boudry; B Collet; F Cornette; V Hervouet; F Bonhomme

2002-01-01

208

Self-mixing laser Doppler vibrometry with high optical sensitivity: application to real-time sound reproduction  

NASA Astrophysics Data System (ADS)

Nanometre vibration measurement of an audio speaker and a highly sensitive sound reproduction experiment have been successfully demonstrated by a self-aligned optical feedback vibrometry technique using the self-mixing modulation effect in a laser-diode-pumped microchip solid-state laser. By applying nanometre vibrations to the speaker, which produced nearly inaudible music below 20 dB (200 µPa) sound pressure level, we could reproduce clear sound in real time by the use of a simple frequency modulated wave demodulation circuit with a -120 dB light-intensity feedback ratio.

Abe, Kazutaka; Otsuka, Kenju; Ko, Jing-Yuan

2003-01-01

209

High rate PLD of diamond-like-carbon utilizing high repetition rate visible lasers.  

National Technical Information Service (NTIS)

Pulsed Laser Deposition (PLD) has been shown to be an effective method for producing a wide variety of thin films of high-value-added materials. The high average powers and high pulse repetition frequencies of lasers under development at LLNL make it poss...

W. McLean E. J. Fehring E. P. Dragon B. E. Warner

1994-01-01

210

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.

211

Neutron-gamma pulse shape discrimination at high count rates  

SciTech Connect

Although pulse shape discrimination has been used for years to separate gamma and neutron interactions in scintillators, many of the best techniques still suffer from count rate limitations. The authors have developed pulse-air-detection techniques which, when used in conjunction with common pulse-shape-discrimination circuits, can markedly improve their performance at high event rates. Performance at rates above 10/sup 6/ events per second has been improved by more than 100%.

Piercey, R.B.; McKisson, J.E.; Banda, M.A.H.; Shavers, M.R.

1987-02-01

212

Curie temperature measurement of metastable alloys using high heating rate  

Microsoft Academic Search

The Curie temperatures (Tc) of amorphous CoxFe85 ? xB15, amorphous and partially crystallized FINEMET metastable alloys were investigated by high heating rate a.c. magnetic measurements. For the Co alloys, the aim was to increase the crystallization temperature above the Curie temperature, using the highest possible heating rate. The highest heating rate achieved was 113 K s?1 (6780 K min ?1).

É. Kisdi-Koszó; L. F. Kiss; L. K. Varga; P. Kamasa

1997-01-01

213

High Pressure Burn Rate Measurements on an Ammonium Perchlorate Propellant  

Microsoft Academic Search

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

E A Glascoe; N Tan

2010-01-01

214

High frame rate thermal imager for hypersonic wind tunnel applications  

Microsoft Academic Search

Infrared thermography is used to derive heat transfer coefficients from thermal mappings of wind tunnel models. Due to the short duration of the runs in hypersonic F4 facilities, a high frame rate infrared camera is needed to record the thermal variations of the model. In accordance with F4 wind tunnel specifications, a 400 Hz frame rate thermal imager was developed.

Stephane Barbe

1992-01-01

215

Combustion Mechanisms of Very High Burn Rate (VHBR) Propellant.  

National Technical Information Service (NTIS)

In this Phase H Small Business Initiated Research (SBlR) program, the various combustion mechanisms of very high burn rate (VHBR) propellant formulations were studied. Toward this end, various diagnostic and specialized instrumentation techniques were dev...

J. T. Barnes E. B. Fisher

1995-01-01

216

High Interest Rates, Spreads, and the Costs of Intermediation.  

National Technical Information Service (NTIS)

Contents: High real interest rates and spreads: An introduction (Spreads and explicit taxes, spreads and implicit taxes on financial intermediation, spreads, operating costs and profits, conclusions and an Agenda for reducing spreads). The costs of interm...

J. A. Hanson R. R. Rocha

1986-01-01

217

High Rate Laser Pitting Technique for Solar Cell Texturing.  

National Technical Information Service (NTIS)

High rate laser pitting technique for solar cell texturing Efficiency of crystalline silicon solar cells can be improved by creating a texture on the surface to increase optical absorption. Different techniques have been developed for texturing, with the ...

H. J. Herfurth

2011-01-01

218

High rate resistive plate chamber for LHC detector upgrades  

NASA Astrophysics Data System (ADS)

The limitation of the detection rate of standard bakelite resistive plate chambers (RPCs) used as muon detectors in the LHC experiments has prevented the use of such detectors in the high rate regions in both CMS and ATLAS detectors. One alternative to these detectors is RPCs made with low resistivity glass plates (1010?cm), a beam test at DESY has shown that such detectors can operate at few thousand Hz/cm2 with high efficiency (>90%).

Haddad, Y.; Laktineh, I.; Grenier, G.; Lumb, N.; Cauwenbergh, S.

2013-08-01

219

Mechanical Properties of Ballistic Gelatin at High Deformation Rates  

Microsoft Academic Search

The characterization of soft or low impedance materials is of increasing importance since these materials are commonly used\\u000a in impact and energy absorbing applications. The increasing role of numerical modeling in understanding impact events requires\\u000a high-rate material properties, where the mode of loading is predominantly compressive and large deformations may occur at\\u000a high rates of deformation. The primary challenge in

C. P. Salisbury; D. S. Cronin

2009-01-01

220

High-strain rate testing of HMX-based explosive  

NASA Astrophysics Data System (ADS)

A split Hopkinson pressure bar (SHPB) was used to measure the mechanical behavior of Navy explosive PBXC-129 (a high-solids-loaded explosive material) with strain rates up to ~3500 s-1. The PBXC-129's high-strain response is typical of other explosive and propellant behavior. At higher strain rates, the PBXC-129 shows significant stiffening with a possible reaction. Stress-strain curves and material properties for PBXC-129 are presented in this paper. .

John, Henry J.; Alamo, Mike F.

2000-04-01

221

Design considerations for high-data-rate chip interconnect systems  

Microsoft Academic Search

Over the past decade, data rates for electrical interconnects in interchip communications systems have experienced a dramatic increase from <;1 Gb\\/s to 10 Gb\\/s and beyond to keep up with ever increasing demands for more I\\/O bandwidth from modern high-capacity storage, networking, and data processing systems. This article presents an overview of the high-data-rate chip interconnect design space, including a

Troy Beukema

2010-01-01

222

Monoclonal antibodies against Nsp2 protein of the highly pathogenic porcine reproductive and respiratory syndrome virus.  

PubMed

Porcine reproductive and respiratory syndrome (PRRS) continues to be a serious threat, causing an economically significant impact on the swine industry worldwide. In this study, non-structural protein Nsp2 of porcine reproductive and respiratory syndrome virus (PRRSV) was expressed in Escherichia coli and purified by dialysis. An important monoclonal antibody (MAb 2H6) against Nsp2 protein was generated by fusing mouse myeloma cell line SP2/0 with spleen lymphocytes from Nsp2 protein immunized mice. Then activity of the MAb was characterized by enzyme-linked immunosorbent assay (ELISA), Western blot analysis, and indirect immunofluorescence assays. The results demonstrated that the MAb has a positive reaction to HP-PRRSV in IFA at 1:100 dilution and in Western blot analysis at 1:500 dilution, and no reaction with classic PRRSV. These indicated that this MAb against Nsp2 protein of PRRSV might be a good candidate for a specific diagnostic method and functional exploration of the Nsp2 protein. PMID:24111869

Li, Bin; Du, Luping; Sun, Bing; Yu, Zhengyu; Wen, Libin; Zhang, Xuehan; Guo, Rongli; Ni, Yanxiu; Hu, Yiyi; Zhou, Junming; Zhu, Haodan; Lv, Lixin; Yu, Yang; Wang, Xiaomin; He, Kongwang

2013-10-01

223

Performance of high flow rate samplers for respirable particle collection.  

PubMed

The American Conference of Governmental Industrial hygienists (ACGIH) lowered the threshold limit value (TLV) for respirable crystalline silica (RCS) exposure from 0.05 to 0.025 mg m(-3) in 2006. For a working environment with an airborne dust concentration near this lowered TLV, the sample collected with current standard respirable aerosol samplers might not provide enough RCS for quantitative analysis. Adopting high flow rate sampling devices for respirable dust containing silica may provide a sufficient amount of RCS to be above the limit of quantification even for samples collected for less than full shift. The performances of three high flow rate respirable samplers (CIP10-R, GK2.69, and FSP10) have been evaluated in this study. Eleven different sizes of monodisperse aerosols of ammonium fluorescein were generated with a vibrating orifice aerosol generator in a calm air chamber in order to determine the sampling efficiency of each sampler. Aluminum oxide particles generated by a fluidized bed aerosol generator were used to test (i) the uniformity of a modified calm air chamber, (ii) the effect of loading on the sampling efficiency, and (iii) the performance of dust collection compared to lower flow rate cyclones in common use in the USA (10-mm nylon and Higgins-Dewell cyclones). The coefficient of variation for eight simultaneous samples in the modified calm air chamber ranged from 1.9 to 6.1% for triplicate measures of three different aerosols. The 50% cutoff size ((50)d(ae)) of the high flow rate samplers operated at the flow rates recommended by manufacturers were determined as 4.7, 4.1, and 4.8 microm for CIP10-R, GK2.69, and FSP10, respectively. The mass concentration ratio of the high flow rate samplers to the low flow rate cyclones decreased with decreasing mass median aerodynamic diameter (MMAD) and high flow rate samplers collected more dust than low flow rate samplers by a range of 2-11 times based on gravimetric analysis. Dust loading inside the high flow rate samplers does not appear to affect the particle separation in either FSP10 or GK2.69. The high flow rate samplers overestimated compared to the International Standards Organization/Comité Européen de Normalisation/ACGIH respirable convention [up to 40% at large MMAD (27.5 microm)] and could provide overestimated exposure data with the current flow rates. However, both cyclones appeared to be able to provide relatively unbiased assessments of RCS when their flow rates were adjusted. PMID:20660144

Lee, Taekhee; Kim, Seung Won; Chisholm, William P; Slaven, James; Harper, Martin

2010-08-01

224

Constitutive behaviors of a silicone rubber at high strain rates  

NASA Astrophysics Data System (ADS)

Silicone rubber is a macromolecule polymer, and can suffer a large deformation. In the paper, the silicone rubber specimens are tested at a series of strain rates by modified SHPB techniques. Based on the experimental data, a constitutive model of the silicone rubber is built up based on Ogden strain energy functions. An interesting phenomenon— localized damage cycle, so called lag circle— shows up in the tested specimen under high strain-rates loading. The diameters of the damage cycle are associated with strain-rate and specimen's size. A formulation about the relations between the diameter and the strain-rate, specimen's size is presented.

Lu, Fangyun; Lin, Yuliang; Lu, Li

2006-08-01

225

High expression in involuting reproductive tissues of uterocalin/24p3, a lipocalin and acute phase protein.  

PubMed Central

During reproduction the mass and number of cells in the uterus and the mammary gland increase rapidly and then diminish more rapidly after their reproductive functions are completed. The diminishment of tissue mass, known as involution, involves an ordered series of events that includes apoptosis of resident cells, neutrophil invasion, the release of degradative enzymes and phagocytosis of cellular debris. Local signals are believed to regulate the progression of involution in each tissue. Here we show that the mammary gland and uterus express high levels of uterocalin, a protein that specifically induces apoptosis in neutrophils and other leucocytes. In the mammary gland, uterocalin expression is induced by weaning. In both tissues, uterocalin is expressed at extremely high levels such that it constitutes an average of 0.2-0.5% of the total extractable protein at its peak. Epithelial cells in the uterus and mammary gland produce uterocalin. In each case, the protein is secreted into the tissue lumen, with mammary-derived uterocalin being found in the milk. The period of highest uterocalin expression in vivo is consistent with the hypothesis that one of its physiological roles is to induce apoptosis of infiltrating neutrophils and thereby delay the entry of neutrophils into the tissue. It is proposed that the role of uterocalin during involution is to provide a window of time during which resident cells are protected from the degradative enzymes, free radicals and other secreted products of activated phagocytes to allow these cells to prepare to survive the processes of involution.

Ryon, Joel; Bendickson, Lee; Nilsen-Hamilton, Marit

2002-01-01

226

High Rate Deep Si Etching using Capacitively Coupled Plasma  

NASA Astrophysics Data System (ADS)

High rate deep Si etching using SF6/O2 gas chemistry by Magnetically-Enhanced Reactive Ion Etch (MERIE) system using a Dipole-Ring Magnet (DRM) is studied. It is capable of etching holes 40 ?m in diameter in a Si substrate at etch rates as high as 50 ?m/min. It was found that the Si etch reaction is dominated by the density of fluorine radicals, which is realized at high frequency and pressure. In holes with higher aspect ratios, it was found that the Si etch rate at the bottom of holes is determined not only by the supply of fluorine radicals, but is also influenced by an etch-inhibiting effect related to the sidewall of the hole. Using an 8 ?m square mask, holes with straight sidewalls were etched to a depth of 60 ?m at an etch rate of 24 ?m/min.

Sakai, Itsuko; Sakurai, Noriko; Ohiwa, Tokuhisa

227

Reproductive success in male savanna baboons  

Microsoft Academic Search

Different techniques have been utilized to ascertain male savanna baboon reproductive success based upon behavioral data. A 19 month field study of the reproductive behavior of savanna baboons in Kenya revealed a high degree of concordance among five different measures of male baboon reproductive success. The number of ejaculations showed the highest correlation with time spent in consort. Male reproductive

Fred B. Bercovitch

1987-01-01

228

Status of Women Indicators, Infant Mortality Rate and Birth Rate: A study of High Crude Birth Rate Districts of Pakistan  

Microsoft Academic Search

Pakistan, with a population of 139 million in 2000, is the seventh most populous country in the world. The historical trends indicate a continuous and exponentially increasing growth in population because of sustained high fertility and declining mortality. Currently the population is growing at around 2.2 percent per annum, one of the highest rates of growth (after Nigeria) in the

Mohammad Pervez Wasim

2002-01-01

229

High-rate mechanical properties of energetic materials  

Microsoft Academic Search

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

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

2010-01-01

230

Novel neutron detector for high rate imaging applications  

Microsoft Academic Search

Next generation neutron science facilities, such as the Spallation Neutron Source, require improved thermal neutron detectors, with high counting rate capability, high spatial resolution, low cost per unit area, and adaptability to unique geometries. We propose a neutron detector technology, based on arrays of boron-lined plastic straws, that satisfies the above requirements. The elemental component of this detector is a

J. L. Lacy; A. Athanasiades; N. N. Shehad; R. A. Austin; C. S. Martin

2002-01-01

231

Lithium-Ion Battery Pulse/High Rate Demonstration.  

National Technical Information Service (NTIS)

Performance of lithium-ion batteries at low temperatures and/or high rates is relatively poor due to high cell internal impedance. The ac impedance spectroscopy was utilized to determine the impedance characteristics of lithium- ion cells as a function of...

J. P. Fellner

2003-01-01

232

Preweaning Productivity of Suckling Goats and Sheep in Guadeloupe (FWI) under Intensive Reproductive Rate and Grazing Management  

Microsoft Academic Search

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

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

2005-01-01

233

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.

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

2013-01-01

234

ASSISTED REPRODUCTIVE TECHNOLOGY REPORTS (ART REPORTS)  

EPA Science Inventory

The Society for Assisted Reproductive Technology (SART), an organization of ART providers affiliated with the American Society for Reproductive Medicine (ASRM), has been collecting data and publishing annual reports of pregnancy success rates for fertility clinics in the United S...

235

High strain rate tensile and compressive effects in glassy polymers  

NASA Astrophysics Data System (ADS)

Polymers are increasingly used in impact and complex high rate loading applications. Generally, the mechanical response of glassy polymers under high strain rates has been determined in compression. Some research programs have studied the combined effects of temperature and strain rate, still primarily in compression, providing better understanding of the physics behind the observed response and enhancing the models for these materials. However, limited data are available in tension, and even more limited are data describing both the compressive and tensile response of the same glassy polymer. This paper investigates the compressive and tensile response of glassy polymers across a range of stain rates from quasi-static to dynamic. Experimental results from dynamic mechanical analysis, quasi-static compression and tension, and split Hopkinson tension/pressure bars on several representative glassy polymers will be presented. The pressure dependant yield in these materials will be discussed through comparison of the tensile and compressive yield stresses.

Jordan, J. L.; Siviour, C. R.; Woodworth, B. T.

2012-08-01

236

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

237

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

238

Half of symbol rate sampling for high density DVD channels  

Microsoft Academic Search

Based on the fact that the effective bandwidth of regenerated RF signals of high density digital versatile disk (DVD) systems is about 1\\/4 T where T is the symbol period, we propose a DVD receiver that can recover source data with rate 1\\/T after 1\\/2 T sampling. This receiver employs an interpolator that increases the data rate to 1\\/T. It

In Seok Hwang; Chan Soo Hwang; Yong Hoon Lee

1999-01-01

239

Compressive behaviour of concrete at high strain rates  

Microsoft Academic Search

Experimental techniques commonly used for high strain-rate testing of concrete in compression, together with the methods used\\u000a for measurement and recording of stress and strain, are critically assessed in the first part of this paper. The physical\\u000a capability of each loading method is discussed and some consideration is given to the definitions used for specifying the\\u000a loading rate. The second

P. H. Bischoff; S. H. Perry

1991-01-01

240

? Domain Rate Control Algorithm for High Efficiency Video Coding.  

PubMed

Rate control is a useful tool for video coding, especially in real-time communication applications. Most of existing rate control algorithms are based on the R-Q model, which characterizes the relationship between bitrate R and quantization Q , under the assumption that Q is the critical factor on rate control. However, with the video coding schemes becoming more and more flexible, it is very difficult to accurately model the R-Q relationship. In fact, we find that there exists a more robust correspondence between R and the Lagrange multiplier ? . Therefore, in this paper, we propose a novel ? -domain rate control algorithm based on the R-? model, and implement it in the newest video coding standard high efficiency video coding (HEVC). Experimental results show that the proposed ? -domain rate control can achieve the target bitrates more accurately than the original rate control algorithm in the HEVC reference software as well as obtain significant R-D performance gain. Thanks to the high accurate rate control algorithm, hierarchical bit allocation can be enabled in the implemented video coding scheme, which can bring additional R-D performance gain. Experimental results demonstrate that the proposed ? -domain rate control algorithm is effective for HEVC, which outperforms the R-Q model based rate control in HM-8.0 (HEVC reference software) by 0.55 dB on average and up to 1.81 dB for low delay coding structure, and 1.08 dB on average and up to 3.77 dB for random access coding structure. The proposed ? -domain rate control algorithm has already been adopted by Joint Collaborative Team on Video Coding and integrated into the HEVC reference software. PMID:25020096

Li, Bin; Li, Houqiang; Li, Li; Zhang, Jinlei

2014-09-01

241

Beam test results of high counting rate MRPCs at GSI  

NASA Astrophysics Data System (ADS)

The usage of electrodes made of semi-conductive glass is an inspiring way of improving the counting rate capability of resistive plate chamber. We developed 6 and 10-gap multi-gap resistive plate chambers (MRPCs) with low resistive silicate glass electrodes (bulk resistivity ˜1010 ?cm) for applications in time-of-flight (TOF) at high counting rates. These two prototypes were tested with secondary irradiation from 2.5 GeV proton beam at GSI. Time resolutions below 90 ps and efficiencies above 90% were obtained at counting rates up to 28 kHz/cm2 for the 10-gap MRPC.

Zhu, Xianglei; Wang, Yi; Wang, Jingbo; Li, Yuanjing; Cheng, Jianping

2010-03-01

242

High-Strain-Rate Compression Testing of Ice  

NASA Technical Reports Server (NTRS)

In the present study a modified split Hopkinson pressure bar (SHPB) was employed to study the effect of strain rate on the dynamic material response of ice. Disk-shaped ice specimens with flat, parallel end faces were either provided by Dartmouth College (Hanover, NH) or grown at Case Western Reserve University (Cleveland, OH). The SHPB was adapted to perform tests at high strain rates in the range 60 to 1400/s at test temperatures of -10 and -30 C. Experimental results showed that the strength of ice increases with increasing strain rates and this occurs over a change in strain rate of five orders of magnitude. Under these strain rate conditions the ice microstructure has a slight influence on the strength, but it is much less than the influence it has under quasi-static loading conditions. End constraint and frictional effects do not influence the compression tests like they do at slower strain rates, and therefore the diameter/thickness ratio of the samples is not as critical. The strength of ice at high strain rates was found to increase with decreasing test temperatures. Ice has been identified as a potential source of debris to impact the shuttle; data presented in this report can be used to validate and/or develop material models for ice impact analyses for shuttle Return to Flight efforts.

Shazly, Mostafa; Prakash, Vikas; Lerch, Bradley A.

2006-01-01

243

[Assisted reproduction. Alternatives].  

PubMed

From the first publications about fertilization in vitro (FIVTE) Patrick Steptoe and Robert Edwards, added several knowledges and new concepts in modern Gynecology, so starting a new era of Reproductive Medicine, so ideating a series of programs and methodologies to emulate the physiological ovarian cycle; with this concept Ricardo Asch carries the transference of gametes to tubes and calling this procedure GIFT. These methodologies with a high technology have been called Assisted Reproduction, which is reviewed in this paper. PMID:8359702

Gorozpe Calvillo, J I; Gómez Arzapalo, E

1993-08-01

244

High strain rate superplasticity in metals and composites  

SciTech Connect

Superplastic behavior at very high strain rates (at or above 1 s{sup {minus}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, and MA 2124 MMC, are presented. Except for the required fine grain size, details of the structural requirements of this phenomenon are not yet understood. Despite this, a systematic approach to produce high strain rate superplasticity (HSRS) in metallic materials is given in this paper. Evidences indicate that the presence of a liquid phase, or a low melting point region, at boundary interfaces is responsible for HSRS.

Nieh, T.G.; Wadsworth, J. [Lawrence Livermore National Lab., CA (United States); Higashi, K. [Osaka Prefecture Univ., Sakai (Japan). Dept. of Mechanicl Systems Engineering

1993-07-01

245

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

246

Longer life span evolves under high rates of condition-dependent mortality.  

PubMed

Aging affects nearly all organisms, but how aging evolves is still unclear. The central prediction of classic theory is that high extrinsic mortality leads to accelerated aging and shorter intrinsic life span. However, this prediction considers mortality as a random process, whereas mortality in nature is likely to be condition dependent. Therefore, the novel theory maintains that condition dependence may dramatically alter, and even reverse, the classic pattern. We present experimental evidence for the evolution of longer life span under high condition-dependent mortality. We employed an experimental evolution design, using a nematode, Caenorhabditis remanei, that allowed us to disentangle the effects of mortality rate (high versus low) and mortality source (random versus condition dependent). We observed the evolution of shorter life span under high random mortality, confirming the classic prediction. In contrast, high condition-dependent mortality led to the evolution of longer life span, supporting a key role of condition dependence in the evolution of aging. This life-span extension was not the result of a trade-off with reproduction. By simultaneously corroborating the classic results [8-10] and providing the first experimental evidence for the novel theory, our study resolves apparent contradictions in the study of aging and challenges the traditional paradigm by demonstrating that condition-environment interactions dictate the evolutionary trajectory of aging. PMID:23084993

Chen, Hwei-Yen; Maklakov, Alexei A

2012-11-20

247

Effect of bis(tributyltin) oxide on reproduction and population growth rate of calanoid copepod Schmackeria poplesia  

NASA Astrophysics Data System (ADS)

A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin) oxide (TBTO). The results indicate no sex-specific differences in TBTO toxicity. Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L-1 were significantly elevated compared with that of control, and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L-1. The percentages of ovigerous females were reduced compared with the control ( P<0.01) after 24 days exposure to concentrations higher than 10 ng TBTO L-1. Histological examinations suggest that exposure to TBTO might block the posterior end of the diverticula and inhibits the production of egg sacs. A modified Euler-Lotka equation was used to calculate a population-level endpoint, the intrinsic rate of natural increase ( r m), from individual life-table endpoints, i.e. mortality rate, time of release of first brood, sex ratio, the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female. Apart from the highest TBTO concentration (60 ng L-1), where all females aborted their egg sacs, 20 ng TBTO L-1 was the only concentration that significantly decreased r m compared with that of control (an effect associated with decreased sex ratio). The results show that the S. poplesia is affected by prolonged exposure to low concentrations of TBTO. The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.

Huang, Ying; Zhu, Liyan; Qiu, Xuchun; Zhang, Tianwen

2010-03-01

248

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.

249

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.

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

2013-01-01

250

High-Strain Rate Mechanical Response of Cured Epoxy Networks  

NASA Astrophysics Data System (ADS)

Chemically cross-linked polymer networks are increasingly common in high performance composites, adhesives and other applications involving high-impact loading conditions or ballistic collisions. The mechanical behavior of epoxy and other polymer networks exhibit a strong dependence on strain rate near the glass transition temperature (Tg); however, the elastic modulus at strain rates greater than 10^5 1/s is difficult to capture with experimental techniques. We present computational results of Di-Glycidyl Ether of Bisphenol A (DGEBA) and Jeffamine diamines (D230) from molecular dynamics simulation, which is intrinsically well-suited to model material deformation at high strain rates. Our results show that the experimental Tg can be reproduced from molecular dynamics, and the Williams-Landel-Ferry equation is useful in rationalizing the shift of Tg due to fast annealing and high strain rates. Temperature sweeps of elastic modulus show the glass-rubber transition to occur over a significantly wider temperature range compared with experimental measurements at low strain rates.

Sirk, Timothy; Khare, Ketan; Karim, Mir; Lenhart, Joseph; Khare, Rajesh; Andzelm, Jan

2013-03-01

251

Solid state pulsed high-repetition-rate excimer lasers  

NASA Astrophysics Data System (ADS)

As the most efficient UV laser sources excimer lasers are unique tools for the various fields of material processing. Essentially, the tight process windows fuel the need for better dose control during laser illumination and hence the demand for high repetition rate excimer lasers operating at comparably low pulse energies of only some 10 mJ. Compact, flexible excimer lasers offering high repetition rate-low energy and low cost of ownership pave the way to efficient mask writing and wafer inspection systems for chip manufacturing as well as to efficient testing of optical materials. Utilizing micro-mirror arrays, high-repetition rate-low energy excimer lasers are ideal for flexible direct-write material processing approaches e.g., in laser marking or cleaning. Moreover, medical applications such as refractive eye surgery currently using up to 200 Hz repetition rate will benefit from high-repetition rate excimer lasers offering reduced treatment times with excimer laser based systems with 500 Hz and even 1000 Hz in the near future.

Delmdahl, Ralph F.; Nikolaus, Bernhard

2004-07-01

252

Flexible high-repetition-rate ultrafast fiber laser.  

PubMed

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

253

High strain rate deformation of NiAl  

SciTech Connect

NiAl is a potential high temperature structural material. Applications for which NiAl is being considered (such as rotating components in jet engines) requires knowledge of mechanical properties over a wide range of strain rates. Single crystal NiAl (stoichiometric and Ni 49.75Al 0.25Fe) has been deformed in compression along [100] at strain rates of 0.001, 0.1/s and 2000/s and temperatures of 76,298 and 773K. <111> slip was observed after 76K testing at a strain rate of 0.001/s and 298K testing at a strain rate of 2000/s. Kinking was observed after deformation at 298K and a strain rate of 0.001/s and sometimes at 298 K and a strain rate of 0.1/s. Strain hardening rates of 8200 and 4000 MPa were observed after 773 and 298K testing respectively, at a strain rate of 2000/s. Results are discussed in reference to resulting dislocation substructure.

Maloy, S.A.; Gray, G.T. III [Los Alamos National Lab., NM (United States); Darolia, R. [General Electric Co., Cincinnati, OH (United States). Aircraft Engines

1994-07-01

254

Temporal pitch perception at high rates in cochlear implants.  

PubMed

A recent study reported that a group of Med-El COMBI 40+CI (cochlear implant) users could, in a forced-choice task, detect changes in the rate of a pulse train for rates higher than the 300 pps "upper limit" commonly reported in the literature [Kong, Y.-Y., et al. (2009). J. Acoust. Soc. Am. 125, 1649-1657]. The present study further investigated the upper limit of temporal pitch in the same group of CI users on three tasks [pitch ranking, rate discrimination, and multidimensional scaling (MDS)]. The patterns of results were consistent across the three tasks and all subjects could follow rate changes above 300 pps. Two subjects showed exceptional ability to follow temporal pitch change up to about 900 pps. Results from the MDS study indicated that, for the two listeners tested, changes in pulse rate over the range of 500-840 pps were perceived along a perceptual dimension that was orthogonal to the place of excitation. Some subjects showed a temporal pitch reversal at rates beyond their upper limit of pitch and some showed a reversal within a small range of rates below the upper limit. These results are discussed in relation to the possible neural bases for temporal pitch processing at high rates. PMID:21117760

Kong, Ying-Yee; Carlyon, Robert P

2010-05-01

255

Low Primary Cesarean Rate and High VBAC Rate With Good Outcomes in an Amish Birthing Center  

PubMed Central

PURPOSE Recent national guidelines encourage a trial of labor after cesarean (TOLAC) as a means of increasing vaginal births after cesarean (VBACs) and decreasing the high US cesarean birth rate and its consequences (2010 National Institute of Health Consensus Statement and American College of Obstetricians and Gynecologists revised guideline). A birthing center serving Amish women in Southwestern Wisconsin offered an opportunity to look at the effects of local culture and practices that support vaginal birth and TOLAC. This study describes childbirth and perinatal outcomes during a 17-year period in LaFarge, Wisconsin. METHODS We undertook a retrospective analysis of the records of all women admitted to the birth center in labor. Main outcome measures include rates of cesarean deliveries, TOLAC and VBAC deliveries, and perinatal outcomes for 927 deliveries between 1993 and 2010. RESULT S The cesarean rate was 4% (35 of 927), the TOLAC rate was 100%, and the VBAC rate was 95% (88 of 92). There were no cases of uterine rupture and no maternal deaths. The neonatal death rate of 5.4 of 1,000 was comparable to that of Wisconsin (4.6 of 1,000) and the United States (4.5 of 1,000). CONCLUSIONS Both the culture of the population served and a number of factors relating to the management of labor at the birthing center have affected the rates of cesarean delivery and TOLAC. The results of the LaFarge Amish study support a low-technology approach to delivery where good outcomes are achieved with low cesarean and high VBAC rates.

Deline, James; Varnes-Epstein, Lisa; Dresang, Lee T.; Gideonsen, Mark; Lynch, Laura; Frey, John J.

2012-01-01

256

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

257

High Strain Rate Testing of HMX Based Explosives  

NASA Astrophysics Data System (ADS)

The split-Hopkinson pressure bar (SHPB) apparatus was used to measure the mechanical behavior of a Navy explosive PBXC-129 with strain rates up to 3000 s-1 . PBXC-129 is a high solids loading explosive material. The high strain response of the PBXC-129 indicates that the material has typical behavior that would be expected from explosives and propellant materials. At the higher strain rates the material shows significant stiffening with possible reaction. The stress-strain curves and material response properties are presented in this paper for PBXC-129 material.

John, Henry

1999-06-01

258

Risk Factors for Malformations and Impact on Reproductive Performance and Mortality Rates of Schmallenberg Virus in Sheep Flocks in the Netherlands  

PubMed Central

In Northwestern Europe, an epizootic outbreak of congenital malformations in newborn lambs due to infection with Schmallenberg virus (SBV) started at the end of 2011. The objectives of this study were to describe clinical symptoms of SBV infection, the effect of infection on mortality rates, and reproductive performance in sheep, as well as to identify and quantify flock level risk factors for SBV infections resulting in malformations in newborn lambs. A case-control study design was used, with 93 case flocks that had notified malformed lambs and 84 control flocks with no such lambs. Overall animal seroprevalence in case flocks was estimated at 82.0% (95% CI: 74.3–87.8), and was not significantly different from the prevalence in control flocks being 76.4% (95% CI: 67.2–83.6). The percentages of stillborn lambs or lambs that died before weaning, repeat breeders, and lambs with abnormal suckling behaviour were significantly higher in case flocks compared to control flocks. However, effect of SBV infection on mortality rates and reproductive performance seemed to be limited. Multivariable analysis showed that sheep flocks with an early start of the mating season, i.e. before August 2011 (OR?=?33.1; 95% CI: 10.0–109.8) and in August 2011 (OR?=?8.2; 95% CI: 2.7–24.6) had increased odds of malformations in newborn lambs caused by SBV compared to sheep flocks with a start of the mating season in October 2011. Other flock-level risk factors for malformations in newborn lambs were purchase of silage (OR 5.0; 95% CI: 1.7–15.0) and flocks with one or more dogs (OR?=?3.3; 95% CI: 1.3–8.3). Delaying mating until October could be a potential preventive measure for naïve animals to reduce SBV induced losses. As duration of immunity after infection with SBV is expected to last for several years, future SBV induced congenital malformations are mainly expected in offspring of early mated seronegative animals.

Luttikholt, Saskia; Veldhuis, Anouk; van den Brom, Rene; Moll, Lammert; Lievaart-Peterson, Karianne; Peperkamp, Klaas; van Schaik, Gerdien; Vellema, Piet

2014-01-01

259

Effects of Selection for Honey Bee Worker Reproduction on Foraging Traits  

PubMed Central

The “reproductive ground plan” hypothesis (RGPH) proposes that reproductive division of labour in social insects had its antecedents in the ancient gene regulatory networks that evolved to regulate the foraging and reproductive phases of their solitary ancestors. Thus, queens express traits that are characteristic of the reproductive phase of solitary insects, whereas workers express traits characteristic of the foraging phase. The RGPH has also been extended to help understand the regulation of age polyethism within the worker caste and more recently to explain differences in the foraging specialisations of individual honey bee workers. Foragers that specialise in collecting proteinaceous pollen are hypothesised to have higher reproductive potential than individuals that preferentially forage for nectar because genes that were ancestrally associated with the reproductive phase are active. We investigated the links between honey bee worker foraging behaviour and reproductive traits by comparing the foraging preferences of a line of workers that has been selected for high rates of worker reproduction with the preferences of wild-type bees. We show that while selection for reproductive behaviour in workers has not altered foraging preferences, the age at onset of foraging of our selected line has been increased. Our findings therefore support the hypothesis that age polyethism is related to the reproductive ground plan, but they cast doubt on recent suggestions that foraging preferences and reproductive traits are pleiotropically linked.

Oldroyd, Benjamin P; Beekman, Madeleine

2008-01-01

260

Machining and grinding: High rate deformation in practice  

SciTech Connect

Machining and grinding are well-established material-working operations involving highly non-uniform deformation and failure processes. A typical machining operation is characterized by uncertain boundary conditions (e.g.,surface interactions), three-dimensional stress states, large strains, high strain rates, non-uniform temperatures, highly localized deformations, and failure by both nominally ductile and brittle mechanisms. While machining and grinding are thought to be dominated by empiricism, even a cursory inspection leads one to the conclusion that this results more from necessity arising out of the complicated and highly interdisciplinary nature of the processes than from the lack thereof. With these conditions in mind, the purpose of this paper is to outline the current understanding of strain rate effects in metals.

Follansbee, P.S.

1993-04-01

261

Machining and grinding: High rate deformation in practice  

SciTech Connect

Machining and grinding are well-established material-working operations involving highly non-uniform deformation and failure processes. A typical machining operation is characterized by uncertain boundary conditions (e.g.,surface interactions), three-dimensional stress states, large strains, high strain rates, non-uniform temperatures, highly localized deformations, and failure by both nominally ductile and brittle mechanisms. While machining and grinding are thought to be dominated by empiricism, even a cursory inspection leads one to the conclusion that this results more from necessity arising out of the complicated and highly interdisciplinary nature of the processes than from the lack thereof. With these conditions in mind, the purpose of this paper is to outline the current understanding of strain rate effects in metals.

Follansbee, P.S.

1993-01-01

262

High-rate mechanical properties of energetic materials  

Microsoft Academic Search

Compared to the many thousands of studies that have been performed on the energy release mechanisms of high energy materials,\\u000a relatively few studies have been performed (a few hundred) into their mechanical properties. Since it is increasingly desired\\u000a to model the high rate deformation of such materials, it is of great importance to gather data on their response so that

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

2010-01-01

263

User microprogrammable processors for high data rate telemetry preprocessing  

NASA Technical Reports Server (NTRS)

The use of microprogrammable processors for the preprocessing of high data rate satellite telemetry is investigated. The following topics are discussed along with supporting studies: (1) evaluation of commercial microprogrammable minicomputers for telemetry preprocessing tasks; (2) microinstruction sets for telemetry preprocessing; and (3) the use of multiple minicomputers to achieve high data processing. The simulation of small microprogrammed processors is discussed along with examples of microprogrammed processors.

Pugsley, J. H.; Ogrady, E. P.

1973-01-01

264

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

265

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

266

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

267

Bats and birds: Exceptional longevity despite high metabolic rates  

Microsoft Academic Search

A B S T R A C T Bats and birds live substantially longer on average than non-flying mammals of similar body size. The combination of small body size, high metabolic rates, and long lifespan in bats and birds would not seem to support oxidative theories of ageing that view senescence as the gradual accumulation of damage from metabolic byproducts.

Jason Munshi-South; Gerald S. Wilkinson

2009-01-01

268

High dose rate brachytherapy for superficial cancer of the esophagus  

Microsoft Academic Search

Purpose: We analyzed our experience with external radiotherapy, combined modality treatment, or HDR brachytherapy alone to limited esophageal cancers.Methods and Materials: From 1991 to 1996, 25 patients with limited superficial esophagus carcinomas were treated by high dose rate brachytherapy. The mean age was 63 years (43–86 years). Five patients showed superficial local recurrence after external radiotherapy. Eleven patients without invasion

Philippe Maingon; Anne d’Hombres; Gilles Truc; Isabelle Barillot; Christophe Michiels; Laurent Bedenne; Jean Claude Horiot

2000-01-01

269

High framing rate PIV studies of an impinging water drop  

Microsoft Academic Search

The flow field formed by the impact of a water drop in the vortex ring region was studied using high framing rate particle image velocimetry (HFRPIV). A survey of the current hardware available for HFRPIV is given followed by the results for a HFRPIV study at 1 kHz (double frames). The HFRPIV results are matched against observations from a dyed

J.-L. Liow; D. E. Cole

2008-01-01

270

Trends in High School Graduation Rates. Research Brief. Volume 0710  

ERIC Educational Resources Information Center

This Research Brief addresses an outcome measure that is of paramount importance to senior high schools--graduation rate. Nationwide a student drops out of school approximately every nine seconds. The significance of this issue locally is exemplified by a recent American Civil Liberties Union filing of a class action law suit against the Palm…

Romanik, Dale; Froman, Terry

2008-01-01

271

Childhood Onset Schizophrenia: High Rate of Visual Hallucinations  

ERIC Educational Resources Information Center

Objective: To document high rates and clinical correlates of nonauditory hallucinations in childhood onset schizophrenia (COS). Method: Within a sample of 117 pediatric patients (mean age 13.6 years), diagnosed with COS, the presence of auditory, visual, somatic/tactile, and olfactory hallucinations was examined using the Scale for the Assessment…

David, Christopher N.; Greenstein, Deanna; Clasen, Liv; Gochman, Pete; Miller, Rachel; Tossell, Julia W.; Mattai, Anand A.; Gogtay, Nitin; Rapoport, Judith L.

2011-01-01

272

High repetition rate effects in XeCl tea lasers  

Microsoft Academic Search

The high repetition rate capability of a discharge pumped XeCl laser with static fill has been studied by double pulse experiments. By suitably selecting the laser parameters (energy deposition, gas mixture composition, filling pressure), following an analytical model of the discharge induced thermal effects, laser action from the second pulse for delays as short as 5 ms with an energy

R. Buffa; P. Burlamacchi; M. Matera; H. F. Ranea Sandoval; R. Salimbeni

1982-01-01

273

Making Composite-Material Parts At Moderate To High Rates  

NASA Technical Reports Server (NTRS)

Composite-material (matrix/fiber) structural components manufactured at moderate to high rates in production-line-style processes, according to proposal. In method, production lines largely automated and takes advantage of fact matrix resins cured by electron beams in addition to heat. Net result reductions in production times and costs.

Farley, Gary L.

1995-01-01

274

High Rates of Staphylococcus aureus USA400 Infection, Northern Canada  

PubMed Central

Surveillance of Staphylococcus aureus infections in 3 northern remote communities of Saskatchewan was undertaken. Rates of methicillin-resistant infections were extremely high (146–482/10,000 population), and most (98.2%) were caused by USA400 strains. Although USA400 prevalence has diminished in the United States, this strain is continuing to predominate throughout many northern communities in Canada.

Golding, George R.; Levett, Paul N.; McDonald, Ryan R.; Irvine, James; Quinn, Brian; Nsungu, Mandiangu; Woods, Shirley; Khan, Mohammad; Ofner-Agostini, Marianna

2011-01-01

275

Testing of polymeric foams at high and medium strain rates  

Microsoft Academic Search

Experimental data of the behaviour of polymeric foams at high and medium strain rates is required in the crash simulations developed in the automotive industry. This paper presents an investigation of particular difficulties in the testing of polymeric foams, using a Split Hopkinson Pressure Bar (SHPB). On the one hand, viscoelastic bars are used to improve the impedance ratio between

Han Zhao

1997-01-01

276

Very High Event Rate Data Acquisition System in FASTBUS.  

National Technical Information Service (NTIS)

A very high event rate Data Acquisition System is described. This DAS is planned for NA36, an SPS heavy ion experiment at CERN that uses calorimetry, wire chambers and a TPC to look for strangeness production enhancement as a signature of the quark-gluon ...

S. E. Eiseman A. Etkin K. J. Foley J. J. Gould R. W. Hackenburg

1985-01-01

277

A teaching booklet for patients receiving high dose rate brachytherapy.  

PubMed

A teaching booklet developed for patients with lung cancer who were about to receive high dose rate (HDR) brachytherapy is described and presented. The booklet was developed by nurses assigned to a radiation oncology center and details the procedure using text and photographs. PMID:1719509

Jordan, L N; Buck, S S

1991-01-01

278

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

279

OPTIMIZATION OF METALLURGICAL PROCESSES USING HIGH RATE BIOTECHNOLOGY  

Microsoft Academic Search

Existing metallurgical operations can be optimized by implementing engineered bioreactor systems in the process configuration. For instance, metals can be recovered safely and economically from process and waste streams using biogenic sulfide. This paper focuses upon possible applications of high rate biotechnology in metallurgy and mining. Metal recovery from liquid streams (process bleed streams, leach water, waste streams), integrated removal

Henk Dijkman; Johannes Boonstra; Rick Lawrence; Cees J. N. Buisman

280

Electrical Suppression of Tinnitus with High-Rate Pulse Trains  

Microsoft Academic Search

Hypothesis: Application of high-rate pulse trains (e.g., 4800 pps) to the cochlea may represent an effective treatment of tinnitus. Background: Tinnitus is a widespread clinical problem with multiple treatments but no cure. A cure for tinnitus would restore the perception of silence. One plausible hypothesis for the origin of tinnitus associated with sensorineural hearing loss is that it is due

Jay T. Rubinstein; Richard S. Tyler; Abigail Johnson; Carolyn J. Brown

2003-01-01

281

Amorphous silicon solar cells prepared at high deposition rates  

NASA Astrophysics Data System (ADS)

This document describes the progress in the research of amorphous silicon solar cells prepared at high deposition rates. By using high excitation frequency (110 MHz) and optimization of deposition conditions, the electronic properties of i-layers deposited from Si2H6 or SiH4 at approximately 2 nm/s approached the properties of low deposition rate films. B(CH3)3 was used as an alternative p-layer doping gas. The results show that B(CH3)3 is a better doping gas than B2H6, due to its better thermal stability and produces a film with better electro-optical properties. The open-circuit voltage, V(sub oc), of the devices has been improved by using a B(CH3)3 p-layer and a better p/i interface layer. The short circuit current density, J(sub sc), was improved by using an ITO/Ag back reflector. The key for fabricating high-deposition-rate SiH4 devices was found to be the p/i interface. As a result, high-deposition-rate cells deposited from both Si2H6 and SiH4 source gases reached 10 percent efficiencies. A 1 sq cm cell deposited at 2 nm/s from Si2H6 reached 10.1 percent initial efficiency as measured by the Solar Energy Research Institute.

Shen, Dashen S.; Bhat, Pawan K.; Chatham, Hood; Matovich, Cheryl; Benson, Amy

1990-08-01

282

Understanding High School Graduation Rates in the District of Columbia  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

283

Understanding High School Graduation Rates in the United States  

ERIC Educational Resources Information Center

Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

Alliance for Excellent Education, 2009

2009-01-01

284

Distance Education: Why Are the Attrition Rates so High?  

ERIC Educational Resources Information Center

Distance education is being hailed as the next best thing to sliced bread. But is it really? Many problems exist with distance-delivered courses. Everything from course development and management to the student not being adequately prepared are problematic and result in high attrition rates in distance-delivered courses. Students initially…

Moody, Johnette

2004-01-01

285

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

286

Wastewater treatment high rate algal ponds for biofuel production  

Microsoft Academic Search

While research and development of algal biofuels are currently receiving much interest and funding, they are still not commercially viable at today’s fossil fuel prices. However, a niche opportunity may exist where algae are grown as a by-product of high rate algal ponds (HRAPs) operated for wastewater treatment. In addition to significantly better economics, algal biofuel production from wastewater treatment

J. B. K. Park; R. J. Craggs; A. N. Shilton

2011-01-01

287

Modelling orthophosphate evolution in a high rate algal pond  

Microsoft Academic Search

High rate algal ponds (HRAPs) are an efficient treatment for controlling wastewater pollution by reducing the organic matter and the inorganic nutrient content. An experimental HRAP was set up in Mèze (France) and sampled over 24 months. A model simulating orthophosphate (PO4) evolution was constructed using Stella II software. It was thought that deterministic modelling of the temporal evolution of

Fabrice Mesplé; Claude Casellas; Marc Troussellier; Jean Bontoux

1996-01-01

288

Dynamic mathematical model of high rate algal ponds (HRAP)  

Microsoft Academic Search

This article presents a mathematical model to describe High-Rate Algal Ponds (HRAPs). The hydrodynamic behavior of the reactor is described as completely mixed tanks in series with recirculation. The hydrodynamic pattern is combined with a subset of River Water Quality Model 1 (RWQM1), including the main processes in liquid phase. Our aim is to develop models for WSPs and aerated

H. Jupsin; E. Praet; J.-L. Vasel

289

Modelling sunlight disinfection in a high rate pond  

Microsoft Academic Search

Studies of disinfection in conventional waste stabilisation ponds (WSPs) suggest that sunlight is an important factor, sometimes interacting with elevated dissolved oxygen and pH. Shallow depth and mixing in ecologically engineered high rate ponds (HRPs) enable greater exposure of wastewater to sunlight than in conventional WSPs, and we hypothesised that the reported efficient disinfection in HRPs may reflect this. We

Rupert J Craggs; Alec Zwart; John W Nagels; Robert J Davies-Colley

2004-01-01

290

A multicode approach for high data rate UWB system design  

Microsoft Academic Search

This contribution provides a very high data rate UWB system design based on direct sequence spreading. In order to attain >500 Mbps for short range communication, two classical solutions are feasible: either use very short spreading sequences or very large bandwidth. These classical strategies increase intersymbol interference. In contrast, our approach consists in allocating multiple long codes to each user.

Mohamed Kamoun; Laurent Mazet; Marc de Courville; Pierre Duhamel

2009-01-01

291

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

292

Assisted reproduction using donor spermatozoa in women aged 40 and above: the high road or the low road?  

PubMed

The effect of age on outcome is one of the most intriguing areas in the assisted reproduction field. In older patients using donor spermatozoa to reproduce, it remains undefined as to which is the treatment of choice: intrauterine insemination (IUI) or IVF/intracytoplasmic sperm injection (ICSI). Since life-table analysis provides data that are easy to use for patient counselling, this study analysed cumulative delivery rates (CDR) in patients using donor spermatozoa undergoing either primarily IUI or IVF/ICSI and patients who eventually switched from IUI to IVF/ICSI. Crude and expected CDR after six IUI cycles and three primary ICSI cycles (no previous IUI) were similar in both groups (24% versus 26% and 29% versus 35%, respectively). Since time-to pregnancy is an important factor in these older patients, ICSI treatment is advised to be started immediately, since a single cycle of ICSI will achieve the same success rate as a much longer period with at least six IUI cycles. If patients switch to ICSI after failed IUI, this only adds marginal benefit in CDR. Nearly all deliveries in the primary ICSI group were achieved in the first cycle. PMID:23523377

De Brucker, Michaël; Camus, Michel; Haentjens, Patrick; Verheyen, Greta; Collins, John; Tournaye, Herman

2013-06-01

293

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

294

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

295

Highly oblique shocks: Diffusion coefficients, acceleration rate and maximum energy  

NASA Astrophysics Data System (ADS)

We examine numerically using Monte Carlo simulations the effect of the diffusion coefficients and the obliquity of the magnetic field to the shock front on the energy gain and the acceleration rate of the accelerated particles in non-relativistic highly oblique shocks. Previous analytical work is justified showing that in highly oblique shocks the smaller the perpendicular diffusion gets compared to the parallel diffusion coefficient values, the greater the energy gain of the cosmic rays to be obtained and under specific conditions the acceleration rate of the particles allows for critical energies to be reached. Based on these circumstances and other striking findings, the cosmic ray spectrum in high energies between 1015eV and about 1018eV can be explained. We estimate the upper limit of energy that cosmic rays could gain in astrophysical sources following models of such as, Supernovae which explode into the interstellar medium, Red Supergiants, and Wolf-Rayet stars.

Meli, A.; Biermann, P. L.

2005-11-01

296

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

297

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

298

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

299

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

300

Ultra-high cooling rate utilizing thin film evaporation  

PubMed Central

This research introduces a cell cryopreservation method, which utilizes thin film evaporation and provides an ultra-high cooling rate. The microstructured surface forming the thin film evaporation was fabricated from copper microparticles with an average diameter of 50??m. Experimental results showed that a cooling rate of approximately 5×104?°C/min was achieved in a temperature range from 10?°C to ?187?°C. The current investigation will give birth to a cell cryopreservation method through vitrification with relatively low concentrations of cryoprotectants.

Su, Fengmin; Ma, Hongbin; Han, Xu; Chen, Hsiu-hung; Tian, Bohan

2012-01-01

301

Ultra-high cooling rate utilizing thin film evaporation.  

PubMed

This research introduces a cell cryopreservation method, which utilizes thin film evaporation and provides an ultra-high cooling rate. The microstructured surface forming the thin film evaporation was fabricated from copper microparticles with an average diameter of 50??m. Experimental results showed that a cooling rate of approximately 5[Formula: see text]10(4)?°C/min was achieved in a temperature range from 10?°C to -187?°C. The current investigation will give birth to a cell cryopreservation method through vitrification with relatively low concentrations of cryoprotectants. PMID:23093807

Su, Fengmin; Ma, Hongbin; Han, Xu; Chen, Hsiu-Hung; Tian, Bohan

2012-09-10

302

Ultra-high cooling rate utilizing thin film evaporation  

NASA Astrophysics Data System (ADS)

This research introduces a cell cryopreservation method, which utilizes thin film evaporation and provides an ultra-high cooling rate. The microstructured surface forming the thin film evaporation was fabricated from copper microparticles with an average diameter of 50 ?m. Experimental results showed that a cooling rate of approximately 5×104 °C/min was achieved in a temperature range from 10 °C to -187 °C. The current investigation will give birth to a cell cryopreservation method through vitrification with relatively low concentrations of cryoprotectants.

Su, Fengmin; Ma, Hongbin; Han, Xu; Chen, Hsiu-hung; Tian, Bohan

2012-09-01

303

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

304

Long-term operation of high rate algal ponds for the bioremediation of piggery wastewaters at high loading rates  

Microsoft Academic Search

The performance of two 464-L high rate algal ponds (HRAPs) treating 20- and 10-folds diluted swine manure at 10days of hydraulic residence time was evaluated under continental climatic conditions in Castilla y Leon (Spain) from January to October. Under optimum environmental conditions (from July to September), both HRAPs supported a stable and efficient carbon and nitrogen oxidation performance, with average

Ignacio de Godos; Saúl Blanco; Pedro A. García-Encina; Eloy Becares; Raúl Muñoz

2009-01-01

305

Vitamin D - roles in women's reproductive health?  

PubMed Central

In the past few years a growing interest in vitamin D can be observed in the lay and biomedical literature due to findings demonstrating a low vitamin D status in the population. In addition to its importance for the regulation of calcium and phosphorus homeostasis recent epidemiologic studies have observed relationships between low vitamin D levels and multiple disease states. This secosteroid hormone also regulates the expression of a large number of genes in reproductive tissues implicating a role for vitamin D in female reproduction. In this report we summarize the recent evidence that vitamin D status influences female reproductive and pregnancy outcomes. Human and animal data suggest that low vitamin D status is associated with impaired fertility, endometriosis and polycystic ovary syndrome. Evidence from observational studies shows higher rates of preeclampsia, preterm birth, bacterial vaginosis and gestational diabetes in women with low vitamin D levels. However, confirmation of experimental observations establishing an association of vitamin D deficiency with adverse reproductive outcomes by high quality observational and large-scale randomized clinical trials is still lacking. The determination of optimal 25(OH)D3 levels in the reproductive period and the amount of vitamin D supplementation required to achieve those levels for the numerous actions of vitamin D throughout a woman's life would have important public health implications.

2011-01-01

306

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

307

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

308

Mechanical characterization of rocks at high strain rate  

NASA Astrophysics Data System (ADS)

The paper presents the dynamic characterization in tension and compression of three rocks, Carrara marble, Onsernone gneiss and Peccia Marble, at high strain-rates. Two versions of a Split Hopkinson Bar have been used. The version for direct tension tests is installed at the DynaMat Laboratory of the University of Applied Sciences of Southern Switzerland, while the traditional version in compression is installed at the Laboratory of Dynamic Investigation of Materials of Lobachevsky State University. Results of the tests show a significantly strain-rate sensitive behaviour, exhibiting dynamic strength increasing with strain-rate. The experimental research has been developed in the frame of the Swiss-Russian Joint Research Program.

Cadoni, E.; Bragov, A. M.; Dotta, M.; Forni, D.; Konstantinov, A.; Lomunov, A.

2012-08-01

309

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

310

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

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

2013-01-01

311

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

312

Investigation of high-rate lithium-thionyl chloride cells  

NASA Astrophysics Data System (ADS)

Chemical analysis of a commercially produced high-rate D-size lithium-thionyl cell was carried out, as a function of rate of discharge (1 ohm and 5 ohms), depth of discharge, and temperature (25 C and -40 C), using specially developed methods for identifying suspected minor cell products or impurities which may effect cell performance. These methods include a product-retrieval system which involves solvent extraction to enhance the recovery of suspected semivolatile minor chemicals, and methods of quantitative GC analysis of volatile and semivolatile products. The nonvolatile products were analyzed by wet chemical methods. The results of the analyses indicate that the predominant discharge reaction in this cell is 4Li + 2SOCl2 going to 4LiCl + S + SO2, with SO2 formation decreasing towards the end of cell life (7 to 12 Ah). The rate of discharge had no effect on the product distribution. Upon discharge of the high-rate cell at -40 C, one cell exploded, and all others exhibited overheating and rapid internal pressure rise when allowed to warm up to room temperature.

Hayes, Catherine A.; Gust, Steven; Farrington, Michael D.; Lockwood, Judith A.; Donaldson, George J.

313

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...

314

Energetics of growth and reproduction in a high-tidal population of the clam Ruditapes decussatus from Urdaibai Estuary (Basque Country, N. Spain)  

Microsoft Academic Search

Energetics of growth and reproduction were studied in a high-tidal population of the clam Ruditapes decussatus living in the Mundaka Estuary in the Biosphere Reserve of Urdaibai (Basque Country, North Spain). The study included an analysis of growth rings on the shells to establish the growth curve as well as seasonal patterns of growth and body condition, and estimates of

M. B. Urrutia; I. Ibarrola; J. I. P. Iglesias; E. Navarro

1999-01-01

315

Development of High-rate Discharge Stationary VRLA Battery  

Microsoft Academic Search

NTT Facilities, Inc. has developed high-rate discharge stationary VRLA batteries (2 V, 200 Ah and 2 V, 300 Ah) for UPSs and data center backups. The battery capacities are 1.35-6.4 times greater at a discharge current of 1-3 CA compared with a conventional battery due to improved plates and poles. We reduced the masses of the batteries by 26% and

T. Tsujikawa; K. Yabuta; T. Matsushita

2006-01-01

316

High rate electrode materials for lithium ion batteries  

Microsoft Academic Search

This paper summarizes our research work on composite-based high rate anode and cathode materials for lithium ion batteries. Elemental Ag, Cu and C were applied as additives to prepare the composites with Li4Ti5O12, LiCoO2, LiMn2O4 and Si etc. It is suggested that the dispersion of the additives in the composites greatly depended on their fabrication processes. The improved electronic conductivity

Zhaoyin Wen; Shahua Huang; Xuelin Yang; Bin Lin

2008-01-01

317

Response of NTS tuff to high strain rate loading  

SciTech Connect

Paintbrush tuff from the Nevada Test Site was subjected to high strain rates using a split-Hopkinson pressure bar. Confined competent and granular specimens were dynamically loaded to 600 MPa and 4000s{sup {minus}1}. For the dry competent tuff the modulus increased from 1.0 to 4.0 GPa as the voids collapse. Water added to the granular tuff reduced the intergrain forces. {copyright} {ital 1996 American Institute of Physics.}

Dick, R.D.; Fourney, W.L.; Williams, J.D. [Mechanical Engineering, University of Maryland, College Park, Maryland 20742 (United States)

1996-05-01

318

High dose rate prostate brachytherapy: the California Endocurietherapy (CET) Method  

Microsoft Academic Search

Background and purpose: To describe the rationale, protocol and procedure for the treatment of prostate cancer using high dose rate brachytherapy (HDR-BT) and a non-fixed template technique.Materials and methods: Between July 1991 and December 1998, 491 patients with carcinoma of the prostate were treated using HDR-BT and a non-fixed template technique. AJC stages T1C–T3B, patients with prior transurethral resections of

D. Jeffrey Demanes; Rodney R Rodriguez; Gillian A Altieri

2000-01-01

319

Homogeneous Nucleation Rate for Highly Supercooled Cirrus Cloud Droplets  

Microsoft Academic Search

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

Kenneth Sassen; Gregory C. Dodd

1988-01-01

320

High rate data systems. [for High Resolution Imaging Spectrometer and SAR  

NASA Technical Reports Server (NTRS)

The characteristics of the high resolution imaging spectrometer (HIRIS) and the synthetic aperture radar (SAR) are described with consideration given to the source of their high data rates. A functional-level description of the end-to-end data flow for HIRIS and SAR is provided. Attention is also given to major technological challenges that must be met in achieving an implementation of the system. Management issues associated with high rate, high volume data are also discussed.

Miller, Richard B.; Nichols, David A.

1987-01-01

321

Concurrent porcine circovirus type 2a (PCV2a) or PCV2b infection increases the rate of amino acid mutations of porcine reproductive and respiratory syndrome virus (PRRSV) during serial passages in pigs.  

PubMed

Porcine reproductive and respiratory syndrome virus (PRRSV) has a high degree of genetic and antigenic variability. The purpose of this study was to determine if porcine circovirus type 2 (PCV2) infection increases genetic variability of PRRSV during serial passages in pigs and to determine if there is a difference in the PRRSV mutation rate between pigs concurrently infected with PCV2a or PCV2b. After 8 consecutive passages of PRRSV alone (group 1), PRRSV with PCV2a (group 2), or PCV2b (group 3) in pigs, the sequences of PRRSV structural genes for open reading frame (ORF) 5, ORF6, ORF7 and the partial non-structural protein gene (Nsp) 2 were determined. The total number of identified amino acid mutations in ORF5, ORF6, ORF7 and Nsp2 sequences was 30 for PRRSV infection only, 63 for PRRSV/PCV2a concurrent infection, and 77 for PRRSV/PCV2b concurrent infection when compared with the original VR2385 virus used to infect the passage 1 pigs. Compared to what occurred in pigs infected with PRRSV only, the mutation rates in ORF5 and ORF6 were significantly higher for concurrent PRRSV/PCV2b infected pigs. The PRRSV/PCV2a pigs had a significantly higher mutation rate in ORF7. The results from this study indicated that, besides ORF5 and Nsp2, the PRRSV structural genes ORF6 and ORF7 were shown to mutate at various degrees when the PRRSV was passaged over time in vivo. Furthermore, a significantly higher mutation rate of PRRSV was observed when pigs were co-infected with PCV2 highlighting the importance of concurrent infections on PRRSV evolution and control. PMID:24036229

Yin, Shuang-Hui; Xiao, Chao-Ting; Gerber, Priscilla F; Beach, Nathan M; Meng, Xiang-Jin; Halbur, Patrick G; Opriessnig, Tanja

2013-12-26

322

Brownian Dynamics of Polymers at High Strain Rates  

NASA Astrophysics Data System (ADS)

We tackle the problem of viscoelastic break-up in high speed flow by employing a mesoscopic bead-spring model for the polymer chains, and by performing Brownian dynamics computations for a variety of extensional flows with high strain rates. The results inform about the level of elastic stresses during elongation, and allow inferences about the scaling of the necking process during rupture. Moreover, the findings clarify the mechanism of chain stretching, informing about the times required for full extension and the role of polymer geometry during elongation.

Kivotides, D.; Theofanous, T. G.

2008-07-01

323

Electrochemical cell with high discharge/charge rate capability  

DOEpatents

A fully charged positive electrode composition for an electrochemical cell includes FeS.sub.2 and NiS.sub.2 in about equal molar amounts along with about 2-20 mole percent of the reaction product Li.sub.2 S. Through selection of appropriate electrolyte compositions, high power output or low operating temperatures can be obtained. The cell includes a substantially constant electrode impedance through most of its charge and discharge range. Exceptionally high discharge rates and overcharge protection are obtainable through use of the inventive electrode composition.

Redey, Laszlo (Downers Grove, IL)

1988-01-01

324

Electrochemical cell with high discharge/charge rate capability  

NASA Astrophysics Data System (ADS)

A fully charged positive electrode composition for an electrochemical cell includes FeS2 and NiS2 in about equal molar amounts along with about 2 to 20 mole % of the reaction product Li2S. Through selection of appropriate electrolyte compositions, high power output or low operating temperatures can be obtained. The cell includes a substantially constant electrode impedance through most of its charge and discharge range. Exceptionally high discharge rates and overcharge protection are obtainable through use of the inventive electrode composition.

Redey, L.

1986-07-01

325

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

326

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

National Technical Information Service (NTIS)

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 ...

A. J. Shih M. B. Grant T. M. Yonushonis T. O. Morris S. B. McSpadden

1998-01-01

327

Method for generating high-energy and high repetition rate laser pulses from CW amplifiers  

DOEpatents

A method for obtaining high-energy, high repetition rate laser pulses simultaneously using continuous wave (CW) amplifiers is described. The method provides for generating micro-joule level energy in pico-second laser pulses at Mega-hertz repetition rates.

Zhang, Shukui

2013-06-18

328

A High Load of Non-neutral Amino-Acid Polymorphisms Explains High Protein Diversity Despite Moderate Effective Population Size in a Marine Bivalve With Sweepstakes Reproduction  

PubMed Central

Marine bivalves show among the greatest allozyme diversity ever reported in Eukaryotes, putting them historically at the heart of the neutralist?selectionist controversy on the maintenance of genetic variation. Although it is now acknowledged that this high diversity is most probably a simple consequence of a large population size, convincing support for this explanation would require a rigorous assessment of the silent nucleotide diversity in natural populations of marine bivalves, which has not yet been done. This study investigated DNA sequence polymorphism in a set of 37 nuclear loci in wild samples of the flat oyster Ostrea edulis. Silent diversity was found to be only moderate (0.7%), and there was no departure from demographic equilibrium under the Wright-Fisher model, suggesting that the effective population size might not be as large as might have been expected. In accordance with allozyme heterozygosity, nonsynonymous diversity was comparatively very high (0.3%), so that the nonsynonymous to silent diversity ratio reached a value rarely observed in any other organism. We estimated that one-quarter of amino acid-changing mutations behave as neutral in O. edulis, and as many as one-third are sufficiently weakly selected to segregate at low frequency in the polymorphism. Finally, we inferred that one oyster is expected to carry more than 4800 non-neutral alleles (or 4.2 cM?1). We conclude that a high load of segregating non-neutral amino-acid polymorphisms contributes to high protein diversity in O. edulis. The high fecundity of marine bivalves together with an unpredictable and highly variable success of reproduction and recruitment (sweepstakes reproduction) might produce a greater decoupling between Ne and N than in other organisms with lower fecundities, and we suggest this could explain why a higher segregating load could be maintained for a given silent mutation effective size.

Harrang, Estelle; Lapegue, Sylvie; Morga, Benjamin; Bierne, Nicolas

2013-01-01

329

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.

330

Characterization of an infrared detector for high frame rate thermography  

NASA Astrophysics Data System (ADS)

The use of a commercially available photodetector based infrared thermography system, operating in the 2-5 µm range, for high frame rate imaging of temperature evolutions in solid materials is investigated. Infrared photodetectors provide a very fast and precise means of obtaining temperature evolutions over a wide range of science and engineering applications. A typical indium antimonide detector will have a thermal resolution of around 4 mK for room temperature measurements, with a noise threshold around 15 to 20 mK. However the precision of the measurement is dependent on the integration time (akin to exposure time in conventional photography). For temperature evolutions that occur at a moderate rate the integration time can be relatively long, enabling a large signal to noise ratio. A matter of increasing importance in engineering is the behaviour of materials at high strain rates, such as those experienced in impact, shock and ballistic loading. The rapid strain evolution in the material is usually accompanied by a temperature change. The temperature change will affect the material constitutive properties and hence it is important to capture both the temperature and the strain evolutions to provide a proper constitutive law for the material behaviour. The present paper concentrates on the capture of the temperature evolutions, which occur at such rates that rule out the use of contact sensors such as thermocouples and electrical resistance thermometers, as their response times are too slow. Furthermore it is desirable to have an indication of the temperature distribution over a test specimen, hence the full-field approach of IRT is investigated. The paper explores the many hitherto unaddressed challenges of IRT when employed at high speed. Firstly the images must be captured at high speeds, which means reduced integration times and hence a reduction in the signal to noise ratio. Furthermore, to achieve the high image capture rates the detector array must be windowed down, therefore there is a compromise made between the extent of the full-field imaging and the temporal resolution of the image capture. In the present work a maximum image capture speed of 15 kHz was achieved with a detector array of 64 × 12 elements and an integration time was 60 µs. Results from initial work on woven E-glass/epoxy tensile specimens are presented.

Fruehmann, R. K.; Crump, D. A.; Dulieu-Barton, J. M.

2013-10-01

331

Dynamic Strength of Metals at High Pressure and Strain Rate  

NASA Astrophysics Data System (ADS)

A new approach to materials science at very high pressures and strain rates has been developed on the Omega laser, using a ramped plasma piston drive. A laser drives an ablative shock through a solid plastic reservoir where it unloads at the rear free surface, expands across a vacuum gap, and stagnates on the metal sample under study. This produces a gently increasing ram pressure, compressing the sample nearly isentropically. The peak pressure on the sample, diagnosed with VISAR measurements, can be varied by adjusting the laser energy and pulse length, gap size, and reservoir density, and obeys a simple scaling relation.^1 This has been demonstrated at OMEGA at pressures to 200 GPa in Al foils. In an important application, using in-flight x-ray radiography, the material strength of solid-state samples at high pressure can be inferred by measuring the reductions in the growth rates (stabilization) of Rayleigh-Taylor (RT) unstable interfaces. RT instability measurements of solid of Al-6061-T6 ^2 and vanadium, at pressures of 20-100 GPa, and strain rates of 10^6 to 10^8 s-1, show clear material strength effects. Modelling results for two constitutive strength models -- Steinberg-Guinan and Preston-Tonks-Wallace, show enhanced dynamic strength that may be correlated with a high-strain-rate, phono-drag mechanism. Data, modeling details and future prospects for this project using the National Ignition Facility laser, will be presented. [1] J. Edwards et al., Phys. Rev. Lett., 92, 075002 (2004). [2] K. T. Lorenz et al., Phys. Plasmas 12, 056309 (2005). This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

Lorenz, Thomas

2006-03-01

332

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

333

High rate reactive sputtering of MoN(x) coatings  

NASA Technical Reports Server (NTRS)

High rate reactive sputtering of MoN(x) films was performed using feedback control of the nitorgen partial pressure. Coatings were made at four different target powers: 2.5, 5.0, 7.5 and 10 kW. No hysteresis was observed in the nitrogen partial pressure vs. flow plot, as is typically seen for the Ti-N system. Four phases were determined by X-ray diffraction: molybdenum, Mo-N solid solution, Beta-Mo2N and gamma-Mo2N. The hardness of the coatings depended upon composition, substrate bias, and target power. The phases present in the hardest films differed depending upon deposition parameters. For example, the Beta-Mo2N phase was hardest (load 25 gf) at 5.0 kW with a value of 3200 kgf/sq mm, whereas the hardest coatings at 10 kW were the gamma-Mo2N phase (3000 kgf/sq mm). The deposition rate generally decreased with increasing nitrogen partial pressure, but there was a range of partial pressures where the rate was relatively constant. At a target power of 5.0 kW, for example, the deposition rates were 3300 A/min for a N2 partial pressure of 0.05 - 1.0 mTorr.

Rudnik, Paul J.; Graham, Michael E.; Sproul, William D.

1991-01-01

334

Taylor dispersion analysis in coiled capillaries at high flow rates.  

PubMed

Taylor Dispersion Analysis (TDA) has been performed for analytes moving at high flow rates in long, coiled capillaries. A thin injection zone of the analyte is stretched by the flow and final distribution of concentration of the analyte at the end of the capillary has the gaussian shape. The high flow rates in coiled capillary generate vortices. They convectively mix the analyte across the capillary. This mixing reduces the width of the gaussian distribution several times in comparison to the width obtained in a straight capillary in standard TDA. We have determined an empirical, scaling equation for the width as a function of the flow rate, molecular diffusion coefficient of the analyte, viscosity of the carrier phase, internal radius of the cylindrical capillary, and external radius of the coiled capillary. This equation can be used for different sizes of capillaries in a wide range of parameters without an additional calibration procedure. Our experimental results of flow in the coiled capillary could not be explained by current models based on approximate solutions of the Navier-Stokes equation. We applied the technique to determine the diffusion coefficients of the following analytes: salts, drugs, single amino acids, peptides (from dipeptides to hexapeptides), and proteins. PMID:23496178

Lewandrowska, Anna; Majcher, Aldona; Ochab-Marcinek, Anna; Tabaka, Marcin; Ho?yst, Robert

2013-04-16

335

Diagnostic value of sperm DNA fragmentation and sperm high-magnification for predicting outcome of assisted reproduction treatment  

PubMed Central

Over the last years, major improvements in the field of male infertility diagnosis have been achieved. The aim of this study was to determine the diagnostic usefulness of sperm DNA integrity and sperm vacuolisation for predicting outcome in infertile couples undergoing in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) treatments. A cohort study from 152 infertile couples undergoing sperm DNA fragmentation and high-magnification tests prior to an assisted reproduction treatment was designed. We found that the most predictive cutoff for pregnancy was 25.5% of DNA fragmentation with a negative predictive value of 72.7% (P=0.02). For the degree of vacuolisation, the best predictor of pregnancy was 73.5% of vacuolated sperm grades III+IV with a negative predictive value of 39.4% (P=0.09), which was not statistically significant. In conclusion, sperm DNA fragmentation greater than 25.5% could be associated with higher probability of failure IVF treatment. Regarding the results of the sperm analysis at high magnification, they do not allow us to predict whether or not patients will become pregnant.

Lopez, Gemma; Lafuente, Rafael; Checa, Miguel A; Carreras, Ramon; Brassesco, Mario

2013-01-01

336

The effect of high and low dose Theileria parva infection on the reproductive function of Boran/Friesian heifers.  

PubMed

Two separate experiments were carried out to find the effect of infection with low and high doses of Theileria parva sporozoites on the cyclical status of Boran/Friesian cross heifers. In each experiment, ten heifers were infected and another four heifers acted as controls. Routine monitoring of estrous behavior, determination of serum progesterone concentrations and palpation of the ovaries per rectum were used to assess the cyclical status of each animal. Two and eight animals died in the T . parva low (TpL) and high (TpH) dose experiments, respectively. Five of eight recovered animals in the TpL group cycled regularly postinfection, while three others had extended periods of ovarian dysfunction postinfection. Both infected and recovered animals in the TpH-group similarly had extended periods of ovarian dysfunction postinfection. All controls in both experiments cycled regularly throughout the study period. Differences in cyclical status were not related to the febrile response, parasitological or hematological differences. The animals that continued to cycle throughout lost the least amount of weight. Animals that stopped cycling lost between 16 and 29% of their initial body weights postinfection. In conclusion, this study confirmed previous anecdotal evidence that theileriosis has an adverse effect on reproduction. Results of this study suggested that this was as an indirect result of weight loss associated with infection and not directly attributed to pathology of target organs. PMID:16727380

Rumberia, R M; Eley, R M; Young, A S; Rowland, A C; Watson, E D

1993-11-01

337

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

338

Impurity effects on high-temperature tensile ductility of iridium alloys at high strain rate  

Microsoft Academic Search

The current study was undertaken to determine what effects, if any, larger amounts of certain impurities (Al,Cr,Fe,Ni, and Si) might have on the physical metallurgy and mechanical properties of the DOP-26 iridium alloy. This report summarizes the effects of these impurities on grain growth behavior and high-temperature high-strain-rate tensile ductility. Comparisons are made to the grain growth behavior and high-strain-rate

C. G. McKamey; E. P. George; E. H. Lee; E. K. Ohriner; L. Heatherly; J. W. Cohron

1999-01-01

339

Eighteen-beam gun design for high power, high repetition rate, broadband multiple-beam klystrons  

Microsoft Academic Search

This paper presents the design of a high repetition rate electron gun to be employed in future high-power broadband multiple-beam amplifiers operating in S-band. Special emphasis is placed on the geometric layout of the gun to ensure high repetition rate operation at moderate beam switching voltages, good beam optics, and optimal beam packing for long life, efficient beam-wave interaction and

Khanh T. Nguyen; Dean E. Pershing; David K. Abe; George Miram; Baruch Levush

2005-01-01

340

Costs of reproduction in a long-lived bird: large clutch size is associated with low survival in the presence of a highly virulent disease.  

PubMed

Fitness costs of reproduction are expected to be more pronounced when the environmental conditions deteriorate. We took advantage of a natural experiment to investigate the costs of reproduction among common eiders (Somateria mollissima) nesting at a site in the Arctic, where an avian cholera epizootic appeared at different magnitudes. We tested the predictions that larger reproductive effort (clutch size) is associated with lower survival or breeding probability the following year, and that this relationship was more pronounced under heightened exposure to the disease. Our results indicate that large clutch sizes were associated with lower survival of female eider ducks, but only when there was heightened exposure to avian cholera, as indexed by eider mortality on site. No cost was observed when cholera was absent or when lesser exposure was evident. This supports the hypothesis that fitness costs of high reproductive effort are higher under unfavourable conditions such as a disease epizootic, and further indicates that being a conservative breeder can increase survival probability, given the presence of a highly virulent disease. PMID:19324661

Descamps, Sébastien; Gilchrist, H Grant; Bêty, Joël; Buttler, E Isabel; Forbes, Mark R

2009-04-23

341

Highly oblique shocks: Diffusion coefficients, acceleration rate and maximum energy  

NASA Astrophysics Data System (ADS)

We examine numerically using Monte Carlo simulations the effect of the diffusion coefficients and the obliquity of the magnetic field to the shock front, on the energy gain and the acceleration rate of the accelerated particles in non-relativistic highly oblique shocks. Previous analytical work (Jokipii 1987) is justified showing that in highly oblique shocks the smaller the perpendicular diffusion gets compared to the parallel diffusion coefficient values, the greater the energy gain of the cosmic rays to be obtained and under specific conditions the acceleration rate of the particles allows for critical energies to be reached. It is confirmed that the diffusive shock acceleration mechanism in non-relativistic highly oblique shocks is indeed efficient to accelerate particles up to energies just above the 'knee' and down close to the 'ankle'. The seed of particles which get accelerated in these shock fronts and in such energies, may come from the remnant winds of astrophysical sources with such magnetic field/plasma nearly perpendicular configurations.

Meli, A.; Biermann, P. L.

342

High-strain-rate deformation and comminution of silicon carbide  

NASA Astrophysics Data System (ADS)

Granular flow of comminuted ceramics governs the resistance for penetration of ceramic armor under impact. To understand the mechanism of the granular flow, silicon carbide was subjected to high-strain, high-strain-rate deformation by radial symmetric collapse of a thick-walled cylinder by explosive. The deformation, under compressive stresses, was carried out in two stages: the first stage prefractured the ceramic, while a large deformation was accomplished in the second stage. The total tangential strain (-0.23) was accommodated by both homogeneous deformation (-0.10) and shear localization (-0.13). Three microstructures, produced by different processing methods, were investigated. The microstructural differences affected the microcrack propagation: either intergranular or transgranular fracture was observed, depending on the processing conditions. Nevertheless, the spacing between shear bands and the shear displacement within the shear bands were not significantly affected by the microstructure. Within the shear bands, the phenomenon of comminution occurred, and the thickness of the shear bands increased gradually with the shear strain. A bimodal distribution of fragments developed inside the shear bands. The comminution proceeded through the incorporation of fragments from the shear-band interfaces and the erosion of fragments inside the shear band. Outside the shear bands, an additional comminution mechanism was identified: localized bending generated comminution fronts, which transformed the fractured material into the comminuted material. The observed features of high-strain-rate deformation of comminuted SiC can be used for validation of computer models for penetration process.

Shih, C. J.; Nesterenko, V. F.; Meyers, M. A.

1998-05-01

343

Characterisation and modelling of structural bonding at high strain rate  

NASA Astrophysics Data System (ADS)

These paper deals with the development of new bonded joint modelling for crash application. A new testing device has been set up on Split Hopkinson bars in order to identify adhesive's properties in assemblies for high strain rate and for different loading angles. These tests led to the development of a new cohesive element model used for solving nonlinear dynamic problems with an explicit integration time scheme. An example illustrates and justifies the development of such a cohesive element under dynamic loading by a good efficiency and a significant saving in calculation time.

Haugou, G.; Bourel, B.; Lauro, F.; Bennani, B.; Lesueur, D.; Morin, D.

2012-08-01

344

A high rate flow-focusing foam generator  

NASA Astrophysics Data System (ADS)

We use a rigid axisymmetric microfluidic flow-focusing device to produce monodisperse bubbles, dispersed in a surfactant solution. The gas volume fraction of the dispersion collected out of this device can be as large as 90%, demonstrating that foam with solid-like viscoelastic properties can be produced in this way. The polydispersity of the bubbles is so low that we observe crystallization of our foam. We measure the diameter of the bubbles and compare these data to recent theoretical predictions. The good control over bubble size and foam gas volume fraction shows that our device is a flexible and promising tool to produce calibrated foam at a high flow rate.

Lorenceau, Elise; Sang, Yann Yip Cheung; Höhler, Reinhard; Cohen-Addad, Sylvie

2006-09-01

345

High Rate Laser Pitting Technique for Solar Cell Texturing  

SciTech Connect

High rate laser pitting technique for solar cell texturing Efficiency of crystalline silicon solar cells can be improved by creating a texture on the surface to increase optical absorption. Different techniques have been developed for texturing, with the current state-of-the-art (SOA) being wet chemical etching. The process has poor optical performance, produces surfaces that are difficult to passivate or contact and is relatively expensive due to the use of hazardous chemicals. This project shall develop an alternative process for texturing mc-Si using laser micromachining. It will have the following features compared to the current SOA texturing process: -Superior optical surfaces for reduced front-surface reflection and enhanced optical absorption in thin mc-Si substrates -Improved surface passivation -More easily integrated into advanced back-contact cell concepts -Reduced use of hazardous chemicals and waste treatment -Similar or lower cost The process is based on laser pitting. The objective is to develop and demonstrate a high rate laser pitting process which will exceed the rate of former laser texturing processes by a factor of ten. The laser and scanning technologies will be demonstrated on a laboratory scale, but will use inherently technologies that can easily be scaled to production rates. The drastic increase in process velocity is required for the process to be implemented as an in-line process in PV manufacturing. The project includes laser process development, development of advanced optical systems for beam manipulation and cell reflectivity and efficiency testing. An improvement of over 0.5% absolute in efficiency is anticipated after laser-based texturing. The surface textures will be characterized optically, and solar cells will be fabricated with the new laser texturing to ensure that the new process is compatible with high-efficiency cell processing. The result will be demonstration of a prototype process that is suitable for scale-up to a production tool and process. The developed technique will have an reducing impact on product pricing. As efficiency has a substantial impact on the economics of solar cell production due to the high material cost content; in essence, improved efficiency through cost-effective texturing reduces the material cost component since the product is priced in terms of $/W. The project is a collaboration between Fraunhofer USA, Inc. and a c-Si PV manufacturer.

Hans J. Herfurth; Henrikki Pantsar

2013-01-10

346

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...

347

Time reproduction during high and low attentional tasks in Alzheimer's Disease "A watched kettle never boils".  

PubMed

A wealth of empirical evidence suggests that directing attention to temporal processing increases perceived duration, whereas drawing attention away from it has the opposite effect. Our work investigates this phenomenon by comparing perceived duration during a high attentional and a low attentional task in Alzheimer's Disease (AD) patients since these participants tend to show attentional deficits. In the high attentional task, AD patients and older adults were asked to perform the interference condition of the Stroop test for 15s while in the low attentional task, they had to fixate on a cross for the same length of time. In both conditions, participants were not aware they would be questioned about timing until the end of the task when they had to reproduce the duration of the previously-viewed stimulus. AD patients under-reproduced the duration of previously-exposed stimulus in the high attentional relative to the low attentional task, and the same pattern was observed in older adults. Due to their attentional deficits, AD patients might be overwhelmed by the demand of the high attentional task, leaving very few, if any, attentional resources for temporal processing. PMID:24794142

El Haj, Mohamad; Omigie, Diana; Moroni, Christine

2014-07-01

348

Radiation Hardened, Modulator ASIC for High Data Rate Communications  

NASA Technical Reports Server (NTRS)

Satellite-based telecommunication services are challenged by the need to generate down-link power levels adequate to support high quality (BER approx. equals 10(exp 12)) links required for modem broadband data services. Bandwidth-efficient Nyquist signaling, using low values of excess bandwidth (alpha), can exhibit large peak-to-average-power ratio (PAPR) values. High PAPR values necessitate high-power amplifier (HPA) backoff greater than the PAPR, resulting in unacceptably low HPA efficiency. Given the high cost of on-board prime power, this inefficiency represents both an economical burden, and a constraint on the rates and quality of data services supportable from satellite platforms. Constant-envelope signals offer improved power-efficiency, but only by imposing a severe bandwidth-efficiency penalty. This paper describes a radiation- hardened modulator which can improve satellite-based broadband data services by combining the bandwidth-efficiency of low-alpha Nyquist signals with high power-efficiency (negligible HPA backoff).

McCallister, Ron; Putnam, Robert; Andro, Monty; Fujikawa, Gene

2000-01-01

349

High frame rate thermal imager for hypersonic wind tunnel applications  

NASA Astrophysics Data System (ADS)

Infrared thermography is used to derive heat transfer coefficients from thermal mappings of wind tunnel models. Due to the short duration of the runs in hypersonic F4 facilities, a high frame rate infrared camera is needed to record the thermal variations of the model. In accordance with F4 wind tunnel specifications, a 400 Hz frame rate thermal imager was developed. An HgCdTe 64 by 64 focal plane array in the 3 to 5 micrometers spectral band is used. The complete set of hardware devices and software is described. The F4 wind tunnel infrared background variation is estimated, in order to evaluate photometric measurement errors. After photometric and spatial criteria analysis, an experimental setup is used to measure camera sensitivity and to test the fixed pattern correction for different sets of parameter values. The minimum resolved temperature difference is less than 0.1K for 50K temperature range with 300K background. To check that the instrument works properly at the 400 Hz frame rate, a frame sequence of a fast thermal event is shown. The camera was then tested in the F4 wind tunnel.

Barbe, Stephane

1992-11-01

350

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.

2013-01-01

351

High-rate lithium thionyl-chloride battery development  

SciTech Connect

We have developed a lithium thionyl-chloride cell for use in a high rate battery application to provide power for a missile computer and stage separation detonators. The battery pack contains 20 high surface area ``DD`` cells wired in a series-parallel configuration to supply a nominal 28 volts with a continuous draw of 20 amperes. The load profile also requires six squib firing pulses of one second duration at a 20 ampere peak. Performance and safety of the cells were optimized in a ``D`` cell configuration before progressing to the longer ``DD` cell. Active surface area in the ``D`` cell is 735 cm{sup 2}, and 1650 cm{sup 2} in the ``DD`` cell. The design includes 1.5M LiAlCl{sub 4}/SOCl{sub 2} electrolyte, a cathode blend of Shawinigan Acetylene Black and Cabot Black Pearls 2000 carbons, Scimat ETFE separator, and photoetched current collectors.

Cieslak, W.R.; Weigand, D.E.

1993-12-31

352

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

PubMed

The pathogenesis of Type 2 highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) in 10-week old swine in the United States was investigated. rJXwn06, rescued from an infectious clone of Chinese HP-PRRSV, replicated in swine with at least 100-fold increased kinetics over U.S. strain VR-2332. rJXwn06 caused significant weight loss, exacerbated disease due to bacterial sepsis and more severe histopathological lung lesions in pigs exposed to HP-PRRSV than to those infected with VR-2332. Novel findings include identification of bacterial species present, the degree of thymic atrophy seen, and the inclusion of contact animals that highlighted the ability of HP-PRRSV to rapidly transmit between animals. Furthermore, comprehensive detailed cytokine analysis of serum, bronchoalveolar lavage fluid, and tracheobronchial lymph node tissue homogenate revealed a striking elevation in levels of cytokines associated with both innate and adaptive immunity in HP-PRRSV infected swine, and showed that contact swine differed in the degree of cytokine response. PMID:23079105

Guo, Baoqing; Lager, Kelly M; Henningson, Jamie N; Miller, Laura C; Schlink, Sarah N; Kappes, Matthew A; Kehrli, Marcus E; Brockmeier, Susan L; Nicholson, Tracy L; Yang, Han-Chun; Faaberg, Kay S

2013-01-20

353

Influence of the High Density Lipoprotein Receptor SR-BI on Reproductive and Cardiovascular Pathophysiology  

Microsoft Academic Search

The high density lipoprotein (HDL) receptor SR-BI (scavenger receptor class B type I) mediates the selective uptake of plasma HDL cholesterol by the liver and steroidogenic tissues. As a consequence, SR-BI can influence plasma HDL cholesterol levels, HDL structure, biliary cholesterol concentrations, and the uptake, storage, and utilization of cholesterol by steroid hormone-producing cells. Here we used homozygous null SR-BI

Bernardo Trigatti; Helen Rayburn; Marisa Vinals; Anne Braun; Helena Miettinen; Marsha Penman; Miki Hertz; Mark Schrenzel; Ludwig Amigo; Attilio Rigotti; Monty Krieger

1999-01-01

354

High Dose Rate Brachytherapy as Prostate Cancer Monotherapy Reduces Toxicity Compared to Low Dose Rate Palladium Seeds  

Microsoft Academic Search

PurposeWe evaluated the potential for differing acute and chronic toxicities between 2 monotherapy methods of image guided conformal brachytherapy, high dose rate (HDR) brachytherapy alone and low dose rate (LDR) permanent palladium seeds.

INGA S. GRILLS; ALVARO A. MARTINEZ; MITCHELL HOLLANDER; RAYWIN HUANG; KENNETH GOLDMAN; PETER Y. CHEN; GARY S. GUSTAFSON

2004-01-01

355

CICLO DE VIDA Y TASAS DE SUPERVIVENCIA Y REPRODUCCIÓN DE Copitarsia incommoda WALKER (LEPIDOPTERA: NOCTUIDAE) EN TRES CULTIVARES DE Brassica oleracea L. LIFE CYCLE AND SURVIVAL AND REPRODUCTION RATES OF Copitarsia incommoda WALKER (LEPIDOPTERA: NOCTUIDAE) IN THREE CULTIVARS OF Brassica oleracea L  

Microsoft Academic Search

This research was carried out to know the biological cycle and the survival and reproduction rates of Copitarsia incommoda, previously known as Copitarsia consueta (Walker) (Angulo and Olivares, 2003), in three different cultivars of Brassica oleracea L., crops on which this species feeds. For this purpose, the demographic technique of life and reproduction tables was used. The study allowed to

Leonardo Flores-Pérez; Néstor Bautista-Martínez; Jorge Vera-Graziano; Jorge Valdez-Carrasco; Andrés O. Angulo; Especialidad en Entomología

356

Construction of high frame rate images with Fourier transform  

NASA Astrophysics Data System (ADS)

Traditionally, images are constructed with a delay-and-sum method that adjusts the phases of received signals (echoes) scattered from the same point in space so that they are summed in phase. Recently, the relationship between the delay-and-sum method and the Fourier transform is investigated [Jian-yu Lu, Anjun Liu, and Hu Peng, ``High frame rate and delay-and-sum imaging methods,'' IEEE Trans. Ultrason. Ferroelectr. Freq. Control (submitted)]. In this study, a generic Fourier transform method is developed. Two-dimensional (2-D) or three-dimensional (3-D) high frame rate images can be constructed using the Fourier transform with a single transmission of an ultrasound pulse from an array as long as the transmission field of the array is known. To verify our theory, computer simulations have been performed with a linear array, a 2-D array, a convex curved array, and a spherical 2-D array. The simulation results are consistent with our theory. [Work supported in part by Grant 5RO1 HL60301 from NIH.

Peng, Hu; Lu, Jian-Yu

2002-05-01

357

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

2004-10-01

358

High energy high rate pulsed power processing of materials by powder consolidation and by railgun deposition  

NASA Astrophysics Data System (ADS)

This exploratory research program was initiated to investigate the potential of using pulse power sources for powder consolidation, deposition and other High Energy High Rate Processing. The characteristics of the High Energy High Rate (1MJ/s) powder consolidation using megampere current pulses from a Homopolar Generator, have been defined. Molybdenum Alloy TZM, A Nickel based metallic glass, Copper graphite composites, and P/M Aluminum Alloy X7091 have been investigated. The powder consolidation process produced high densification rates. Density values of 80% to 99% could be obtained with sub second high temperature exposure. Specific energy input and applied pressure were controlling process parameters. Time Temperature Transformation (TTT) concepts underpin a fundamental understanding of pulsed power processing. Deposition experiments were conducted using an exploding foil device (EFD) providing an armature feed to railgun mounted in a vacuum chamber. The material to be deposited - in plasma, gas, liquid or solid state - was accelerated electromagnetically in the railgun and deposited on a substrate.

Persad, C.; Marcus, H. L.; Weldon, W. F.

1987-03-01

359

Transfer functions for high-rate GNSS receivers  

NASA Astrophysics Data System (ADS)

In recent years the development of GPS receivers with sampling rates as high as 100Hz has sparked interest in capturing high-dynamic motions and has potentially enlarged the applicability in navigation, positioning and Earth monitoring. The additional yield of information due to increased sampling rates, however, may be counteracted by a strong correlation of the measurements in time. Unfortunately, the tracking loop filters of the receivers produce correlations exactly in the frequency range (1-100Hz) of the expected benefit of high-rate receivers. The consequences of the correlations between subsequent epochs can be demonstrated by increased amplitude and phase retrieval errors during accelerated motions. The magnitude of these deviations directly depends on the bandwidth of the used tracking loops. A minimization of tracking loop-induced errors can be achieved in two ways: (1) by the optimization of the receiver tracking loop parameters (a larger bandwidth reduces the amplitude errors at high accelerations) and (2) by inverse filtering with a pre-estimated receiver transfer function. Especially for receivers with low and fixed tracking loop bandwidths the determination of a transfer function is crucial. In this presentation an approach to retrieve an empirical transfer function will be demonstrated. A lot of GPS coordinate time series with a broad variety of motions generated by a single-axis shake table have been produced. The discrepancies between the actual shake table motion (measured by inductive sensors) and the motions derived from the data of various GPS receivers are the basis for the determination of (receiver-specific) transfer functions.. The discrete transfer functions are modeled as an Autoregressive Moving Average (ARMA) using the least-squares method. The transfer function can be decomposed into two terms, the moving average of the input (shake table or signal simulator) and the auto-regression of the output (GPS signal). The major challenges to retrieve an empirical transfer function from real measurements are the measurement noise and the time-dependent parameters (e.g. changes in the tracking loop bandwidths dependent on the signal strength).

Häberling, Simon; Rothacher, Markus; Geiger, Alain

2014-05-01

360

The 2011 Grímsvötn Eruption From High Rate Geodesy  

NASA Astrophysics Data System (ADS)

High rate geodetic measurements at volcanoes can give displacements at sub second intervals, revealing surface deformation associated with magma movements. The Grímsvötn volcano lies beneath the Vatnajökull icecap, Iceland, limiting the near field monitoring efforts to a single nunatak, Mt. Grímsfjall, on the southern caldera rim. A 5 Hz GPS station and an electronic tilt meter are located at Grímsfjall. The colocation of these instruments (GPS and tilt station) allows us to relate the observed surface deformation to pressure change in a magma chamber assuming a simple Mogi source within an elastic half space. During the 21-28 May 2011 Grímsvötn eruption a continuous stream of data, despite the eruption plume and lightning, was transmitted to Reykjavík. The tiltmeter measures N-S and E-W components of tilt, the N-S component was recorded at 100 samples per second (sps) but the E-W component at 4 sps. The high rate data from the GPS station at Grímsfjall (GFUM) were analyzed using the Track part of GAMIT/GLOBK. We produced kinematic solutions at 5 Hz and 1 Hz intervals using reference stations in 40-120 km distance of the volcano. To minimize multipath effects we applied sidereal filtering and stacked the individual solutions to further improve the signal to noise ratio. The resulting deformation time series suggests a rapid pressure drop starting about 50 minutes prior to the onset of the eruption when over 20 km high plume formed. The characteristics of the GPS and tilt data time series suggests that the main signal was induced by a single source of fixed location and geometry throughout the eruption; a shallow magma chamber. Small deviations in displacement direction prior to the onset of the eruption can be explained by the opening of the feeder dike. We see a total displacement of 57 cm in direction ˜N38.5°W and down at the GPS station, suggesting a source depth of ~1.7 km. About 20% of the displacement preceded the eruption and more than 95% took place within 24 hours of the onset of deformation. Thus real time high rate geodesy could play an important role in foreseeing both the onset and the evolution of explosive eruptions.

Hreinsdottir, S.; Grapenthin, R.; Sigmundsson, F.; Roberts, M. J.; Holmjarn, J.; Geirsson, H.; Arnadottir, T.; Bennett, R. A.; Villemin, T.; Ofeigsson, B. G.; Sturkell, E. C.

2011-12-01

361

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.

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

362

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

PubMed

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

2012-09-11

363

High dose rate intraluminal irradiation in recurrent endobronchial carcinoma  

SciTech Connect

Palliative therapy for previously irradiated patients with symptomatic recurrent endobronchial malignancy is a difficult problem. We have had the opportunity to treat 20 such patients with high dose rate (50-100 rad/min) endobronchial brachytherapy. Eligible patients had received previous high dose thoracic irradiation (TDF greater than or equal to 90), a performance status of greater than or equal to 50, and symptoms caused by a bronchoscopically defined and implantable lesion. The radiation is produced by a small cobalt-60 source (0.7 Ci) remotely afterloaded by cable control. The source is fed into a 4 mm diameter catheter which is placed with bronchoscopic guidance; it may oscillate if necessary to cover the lesion. A dose of 1,000 rad at 1 cm from the source is delivered. We have performed 22 procedures in 20 patients, four following YAG laser debulking. Most had cough, some with hemoptysis. Eight had dyspnea secondary to obstruction and three had obstructive pneumonitis. In 12, symptoms recurred with a mean time to recurrence of 4.3 months (range 1-9 months). Eighteen patients were followed-up and reexamined via bronchoscope 1-2.5 months following the procedure; two were lost to follow-up. All had at least 50 percent clearance of tumor, and six had complete clearance; most regressions were documented on film or videotape. In six, the palliation was durable. The procedure has been well tolerated with no toxicity. We conclude that palliative endobronchial high dose rate brachytherapy is a useful palliative modality in patients with recurrent endobronchial symptomatic carcinoma.

Seagren, S.L.; Harrell, J.H.; Horn, R.A.

1985-12-01

364

High-fidelity reproduction of spatiotemporal visual signals for retinal prosthesis.  

PubMed

Natural vision relies on spatiotemporal patterns of electrical activity in the retina. We investigated the feasibility of veridically reproducing such patterns with epiretinal prostheses. Multielectrode recordings and visual and electrical stimulation were performed on populations of identified ganglion cells in isolated peripheral primate retina. Electrical stimulation patterns were designed to reproduce recorded waves of activity elicited by a moving visual stimulus. Electrical responses in populations of ON parasol cells exhibited high spatial and temporal precision, matching or exceeding the precision of visual responses measured in the same cells. Computational readout of electrical and visual responses produced similar estimates of stimulus speed, confirming the fidelity of electrical stimulation for biologically relevant visual signals. These results suggest the possibility of producing rich spatiotemporal patterns of retinal activity with a prosthesis and that temporal multiplexing may aid in reproducing the neural code of the retina. PMID:24910077

Jepson, Lauren H; Hottowy, Pawel; Weiner, Geoffrey A; Dabrowski, W?adys?aw; Litke, Alan M; Chichilnisky, E J

2014-07-01

365

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

366

High rate anaerobic thermophilic technologies for distillery wastewater treatment.  

PubMed

In this paper, performance of two high rate technologies, upflow anaerobic fixed-film reactor and fluidized bed laboratory-scale, treating distillery wastewater (wine vinasses) at anaerobic thermophilic conditions have been compared. The results obtained show that the stationary packed bed, with a corrugated plastic support, operated under stable conditions at organic loading rates (OLR0) around 20 kgCOD/m3/d, gives maximal total CODr of 76% at OLR0 of 6.29 kgCOD/m3/d; the fluidized bed reactor, operated on open pore sintered-glass media, gives total CODr of 96% at OLR0 of 5.88 kgCOD/m3/d. The anaerobic fluidized bed technology is more effective than the upflow anaerobic fixed-film technology due, fundamentally, to this technology favouring the transport of microbial cells from the bulk to the surface and enhancing the contact between the microorganism-substrate phases, In this sense, the stationary packed bed technology is adequate for the treatment of easily biodegradable wastewater, or for the cases where elevated percentages of CODr removal are not required, while the fluidized bed technology is especially suitable for treatment of hazardous wastes with recalcitrant compositions. PMID:15771116

Pérez-García, M; Romero-García, L I; Rodríguez-Cano, R; Sales-Márquez, D

2005-01-01

367

Dynamic mathematical model of high rate algal ponds (HRAP).  

PubMed

This article presents a mathematical model to describe High-Rate Algal Ponds (HRAPs). The hydrodynamic behavior of the reactor is described as completely mixed tanks in series with recirculation. The hydrodynamic pattern is combined with a subset of River Water Quality Model 1 (RWQM1), including the main processes in liquid phase. Our aim is to develop models for WSPs and aerated lagoons, too, but we focused on HRAPs first for several reasons: Sediments are usually less abundant in HRAP and can be neglected, Stratification is not observed and state variables are constant in a reactor cross section, Due to the system's geometry, the reactor is quite similar to a plugflow type reactor with recirculation, with a simple advection term. The model is based on mass balances and includes the following processes: *Phytoplankton growth with NO3-, NO2- and death, *Aerobic growth of heterotrophs with NO3-, NH4+ and respiration, *Anoxic growth of heterotrophs with NO3-, NO2- and anoxic respiration, *Growth of nitrifiers (two stages) and respiration. The differences with regard to RWQM1 are that we included a limiting term associated with inorganic carbon on the growth rate of algae and nitrifiers, gas transfers are taken into account by the familiar Adeney equation, and a subroutine calculates light intensity at the water surface. This article presents our first simulations. PMID:14510211

Jupsin, H; Praet, E; Vasel, J L

2003-01-01

368

Investigating the confining compressibility of STF at high deformation rate  

NASA Astrophysics Data System (ADS)

The split Hopkinson pressure bar (SHPB) was used to study the compressibility of shear thickening fluid (STF) at high deformation rate. In this study, a steel bulk was introduced into the SHPB system to confine and load the STF. A series of STFs with different particle types (SiO2 and PSt-EA) and volume fractions (63 vol.% and 65 vol.%) were tested and the results were compared. The reliability of the results was proved by repeating the tests and the force balance in suspension. The bulk modulus was used to evaluate the compressibility of STF, which indicated that the SiO2-based STF exhibited a larger compressibility than the PSt-EA-based STF. It was found that the bulk modulus increases with increasing of the strain rate and the volume fraction shows little effect on the bulk modulus. The structure-dependent mechanical property was analyzed and the loading effect of bulk modulus was considered to be originated from the interparticle clustering.

Jiang, Weifeng; Gong, Xinglong; Xu, Yulei; Xuan, Shouhu; Jiang, Wanquan; Zhu, Wei; Li, Xiaofeng; Qin, Lijun

2012-12-01

369

High-rate Iranian blowout controlled while still burning  

SciTech Connect

Oil well firefighters used ingenuity and equipment designed in the field to cap a high-rate blowout well in Iran without extinguishing the fire. Well AZ-50, located about 25 km southeast of Ahwaz, Iran, blew out on Feb. 14, 1993, and was finally controlled on Mar. 31, 1993, by a firefighting team from the National Iranian Oil Co. The estimated open flow potential of producing Well AZ-50 was 60,000 bo/d and 50 MMsfd of associated gas, making this well among the world's largest blowouts. The well control operation was difficult because the flame height reached 117 m, the fluid velocity 2, 180 fps at the well-head, and the flame temperature 4,150 F. The paper describes operations.

Bahmani, H.; Azarpanah, A. (National Iranian Oil Co., Ahwaz (Iran, Islamic Republic of))

1994-09-19

370

An Aerogel ?erenkov Detector with High Rate Capability  

NASA Astrophysics Data System (ADS)

The excitation spectra of medium mass hypernuclei will be studied by the (e,e'K^+) reaction at a new spectrometer system to be deployed at Jefferson Lab by the E01-011 collaboration. The high background rates expected require an efficient trigger level particle identification. An aerogel ?erenkov detector will be employed for pion suppression. This detector is being developed and built at Florida International University. It will consist of three layers of segmented aerogel ?erenkov detectors. A prototype consisting of one segment only has been built and recently was tested in a mixed hadron beam at KEK. On average, roughly 20 photoelectrons have been observed for pions with 1.2 GeV/c momentum. After presenting the design and the results from the prototype, we will discuss the expected performance characteristics of the full system under the predicted experimental conditions.

Carl, Michael; Reinhold, Joerg

2002-10-01

371

Nursing care of the patient receiving high dose rate brachytherapy.  

PubMed

Over the past few decades, a significant increase in the incidence of lung cancer has occurred. In the majority of patients, the failure to cure lung cancer is related in part to an inability to obtain locoregional control of the disease. Remote afterloading high dose rate (HDR) brachytherapy has tremendous potential as a way to increase treatment to the primary site of lung cancer and to improve palliative management of recurrent disease when conventional treatments have failed. Because remote afterloading is used, the medical staff is not exposed to ionizing radiation, and since the duration of treatment is short, HDR brachytherapy is convenient for the patient and can be delivered on an outpatient basis. Fifty-two patients were treated endobronchially for carcinoma of the lung at Parkview Regional Oncology Center in Fort Wayne, IN, between May 1, 1988, and September 1, 1990. Nursing care during treatment and recovery of these patients will be discussed in this paper. PMID:1945963

Jordan, L N; Mantravadi, R V

1991-01-01

372

Methanol conversion in high-rate anaerobic reactors.  

PubMed

An overview on methanol conversion in high-rate anaerobic reactors is presented, with the focus on technological as well as microbiological aspects. The simple C1-compound methanol can be degraded anaerobically in a complex way, in which methanogens, sulfate reducing bacteria and homoacetogens interact cooperatively or competitively at substrate level. This interaction has large technological implications as it determines the final product of methanol mineralization, methane or carbon dioxide. The degradation route of methanol may be entirely different when environmental conditions change. Direct methanogenesis from methanol seems the predominant mineralization route under mesophilic conditions both in the absence and the presence of sulfate. Under thermophilic conditions methanol oxidation to carbon dioxide and hydrogen appears to play an important role. The UASB technology for mesophilic digestion of methanolic waste has presently reached full-scale maturity. The potential of methanol as feedstock for anaerobic processes is discussed. PMID:11730139

Weijma, J; Stams, A J

2001-01-01

373

High-repetition-rate amplification of 16. mu. m radiation  

SciTech Connect

High-repitition-rate generation of up to 325 mJ of Raman amplified radiation near 615 cm/sup -1/ has been demonstrated in CO/sub 2/-pumped para-H/sub 2/ using a low-power, microwave-shifted CF/sub 4/ laser as an input Stokes seed source. Experiments were limited to 200 Hz, but single-shot Schlieren measurements indicate that our flowing room-temperature 44-pass Raman converter should be capable of the design goal of 1 kHz. Strong conversion was achieved even with no flow at 100 Hz. Details of the overall system design, experimental parameters, and present system limitations are discussed.

Kurnit, N.A.; Watkins, D.E.; York, G.W.

1983-01-01

374

Wastewater treatment high rate algal ponds for biofuel production.  

PubMed

While research and development of algal biofuels are currently receiving much interest and funding, they are still not commercially viable at today's fossil fuel prices. However, a niche opportunity may exist where algae are grown as a by-product of high rate algal ponds (HRAPs) operated for wastewater treatment. In addition to significantly better economics, algal biofuel production from wastewater treatment HRAPs has a much smaller environmental footprint compared to commercial algal production HRAPs which consume freshwater and fertilisers. In this paper the critical parameters that limit algal cultivation, production and harvest are reviewed and practical options that may enhance the net harvestable algal production from wastewater treatment HRAPs including CO(2) addition, species control, control of grazers and parasites and bioflocculation are discussed. PMID:20674341

Park, J B K; Craggs, R J; Shilton, A N

2011-01-01

375

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

376

The status of low dose rate and future of high dose rate Cf-252 brachytherapy  

SciTech Connect

This work describes the current status of the US low dose rate (LDR) Cf-252 brachytherapy program. The efforts undertaken towards development of a high dose rate (HDR) remotely after loaded Cf-252 source, which can accommodate 1 mg or greater Cf-252, are also described. This HDR effort is a collaboration between Oak Ridge National Laboratory (ORNL), commercial remote after loader manufactures, the Gershenson Radiation Oncology Center (ROC), and Wayne State University. To achieve this goal, several advances in isotope chemistry and source preparation at ORNL must be achieved to yield a specific material source loading of greater than or equal 1 mg Cf-252 per mm3. Development work with both radioactive and non-radioactive stand-ins for Cf-252 have indicated the feasibility of fabricating such sources. As a result, the decreased catheter diameter and computer controlled source placement will permit additional sites (e.g. brain, breast, prostate, lung, parotid, etc.) to be treated effectively with Cf-252 sources. Additional work at the Radiochemical Engineering and Development Center (REDC) remains in source fabrication, after loader modification, and safe design. The current LDR Cf-252 Treatment Suite at the ROC is shielded and licensed to hold up to 1 mg of Cf-252. This was designed to maintain cumulative personnel exposure, both external to the room and in direct isotope handling, at less than 20 microSv/hr. However, cumulative exposure may be greatly decreased if a Cf-252 HDR unit is employed which would eliminate direct isotope handling and decrease treatment times from tilde 3 hours to an expected range of 3 to 15 minutes. Such a Cf-252 HDR source will also demonstrate improved dose distributions over current LDR treatments due to the ability to step the point-like source throughout the target volume and weight the dwell time accordingly.

Rivard, M.J.; Wierzbicki, J.G.; Van den Heuvel, F.; Chuba, P.J.; Fontanesi, J. [Wayne State Univ., Detroit, MI (United States). Dept. of Radiation Oncology; Martin, R.C.; McMahon, R.R.; Haire, R.G. [Oak Ridge National Lab., TN (United States)

1997-12-01

377

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.

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

2003-01-01

378

Lifetime reproductive effort.  

PubMed

In a 1966 American Naturalist article, G. C. Williams initiated the study of reproductive effort (RE) with the prediction that longer-lived organisms ought to expend less in reproduction per unit of time. We can multiply RE, often measured in fractions of adult body mass committed to reproduction per unit time, by the average adult life span to get lifetime reproductive effort (LRE). Williams's hypothesis (across species, RE decreases as life span increases) can then be refined to read "LRE will be approximately constant for similar organisms." Here we show that LRE is a key component of fitness in nongrowing populations, and thus its value is central to understanding life-history evolution. We then develop metabolic life-history theory to predict that LRE ought to be approximately 1.4 across organisms despite extreme differences in production and growth rates. We estimate LRE for mammals and lizards that differ in growth and production by five- to tenfold. The distributions are approximately normal with means of 1.43 and 1.41 for lizards and mammals, respectively (95% confidence intervals: 1.3-1.5 and 1.2-1.6). Ultimately, therefore, a female can only produce a mass of offspring approximately equal to 1.4 times her own body mass during the course of her life. PMID:18171160

Charnov, Eric L; Warne, Robin; Moses, Melanie

2007-12-01

379

Evaluation of Short-Term Exposure to High Temperature as a Tool to Suppress the Reproductive Development of Channel Catfish for Aquaculture  

Microsoft Academic Search

Short-term exposures to elevated temperatures reduce germ cell numbers in the gonads of some fishes, suggesting that heat treatment may be a viable method for delaying or suppressing reproductive development in cultured fishes. The objective of this study was to determine the effects of high temperatures on early gonadal development in channel catfish Ictalurus punctatus. Twenty-three-day-old (after hatching) channel catfish

M. Todd Byerly; Said I. Fat-Halla; Robert K. Betsill; Reynaldo Patiño

2005-01-01

380

Impurity effects on high-temperature tensile ductility of iridium alloys at high strain rate  

SciTech Connect

The current study was undertaken to determine what effects, if any, larger amounts of certain impurities (Al,Cr,Fe,Ni, and Si) might have on the physical metallurgy and mechanical properties of the DOP-26 iridium alloy. This report summarizes the effects of these impurities on grain growth behavior and high-temperature high-strain-rate tensile ductility. Comparisons are made to the grain growth behavior and high-strain-rate tensile properties of the DOP-26 alloy without intentional impurity additions.

McKamey, C.G.; George, E.P.; Lee, E.H.; Ohriner, E.K.; Heatherly, L.; Cohron, J.W.

1999-12-17

381

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

382

Highly nonlinear defect-induced carrier recombination rates in semiconductors  

NASA Astrophysics Data System (ADS)

Defects in semiconductors can induce recombination of carriers and thus can strongly influence the efficiency and performance of solid-state devices. In the analysis of device performance, defect-induced recombination is often assumed to depend linearly on the carrier concentration or to be given by a sum of Shockley-Read-Hall expressions taken independently for each known defect level. Under these assumptions, defect-induced recombination increases with carrier concentration more slowly than both band-to-band radiative recombination and Auger recombination and becomes relatively less important at higher carrier concentrations. However, we show that defects with multiple defect levels can induce recombination with a highly nonlinear dependence on carrier concentration. For such defects, the usual assumptions about the relative importance of different recombination mechanisms at different carrier concentrations may fail. In order to demonstrate the potential impact of this phenomenon on realistic devices, we incorporate the defect-induced recombination rates obtained from our analysis into a microscopic InGaN/GaN light-emitting diode (LED) model. Our results indicate that a particular class of defects with plausible properties can induce a loss of optical efficiency at carrier concentrations relevant for high-power LED operation.

Modine, N. A.; Armstrong, A. M.; Crawford, M. H.; Chow, W. W.

2013-10-01

383

High strain rate fracture behaviour of fused silica  

NASA Astrophysics Data System (ADS)

Fused silica is a high purity synthetic amorphous silicon dioxide characterized by low thermal expansion coefficient, excellent optical qualities and exceptional transmittance over a wide spectral range. Because of its wide use in the military industry as window material, it may be subjected to high-energy ballistic impacts. Under such dynamic conditions, post-yield response of the ceramic as well as the strain rate related effects become significant and should be accounted for in the constitutive modelling. In this study, the Johnson-Holmquist (J-H) model parameters have been identified by inverse calibration technique, on selected validation test configurations, according to the procedure described hereafter. Numerical simulations were performed with LS-DYNA and IMPETUS-FEA, a general non-linear finite element software which offers NURBS finite element technology for the simulation of large deformation and fracture in materials. In order to overcome numerical drawbacks associated with element erosion, a modified version of the J-H model is proposed.

Ruggiero, A.; Iannitti, G.; Testa, G.; Limido, J.; Lacome, J. L.; Olovsson, L.; Ferraro, M.; Bonora, N.

2014-05-01

384

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.

2013-01-01

385

Development of Indirect ELISAs for Differential Serodiagnosis of Classical and Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus.  

PubMed

The objective of this study was to develop two indirect enzyme-linked immunosorbent assays (iELISAs) for detection of serum antibodies against classical vaccine strain of porcine reproductive and respiratory syndrome virus (PRRSV) and highly pathogenic PRRSV (HP-PRRSV). To detect the common antibodies against classical and HP-PRRSV, the coating antigen used in the iELISA (designated iELISA-180) was the antigen of Nsp2-180, the 180aa at amino terminal of Nsp2. To detect the different antibodies against classical and HP-PRRSV, the coating antigen in the second iELISA (designated iELISA-D29) was Nsp2-D29, the deleted 29aa in Nsp2 of HP-PRRSV. The antigen concentration and serum dilutions were optimized using a draughtboard titration. The cut-off values of 0.361 at OD450nm for the iELISA-180 and 0.27 at OD450nm for the iELISA-D29 were determined by testing a panel of 120 classical PRRSV positive and 198 PRRSV negative pig serum samples, which generated the specificity of 97.1% and 96.7%, the sensitivity of 96.9% and 96.3% for iELISA-180 and iELISA-D29, respectively. The agreements between the Western blot and iELISA-180 and iELISA-D29 were 98%, 96.7%, respectively. The developed iELISAs can be used to differentiate serologically HP-PRRSV from the vaccinated or classical PRRSV in clinical serum samples. PMID:23217174

Xiao, Y H; Wang, T T; Zhao, Q; Wang, C B; Lv, J H; Nie, L; Gao, J M; Ma, X C; Hsu, W H; Zhou, E M

2014-08-01

386

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.

Kappes, Matthew A.; Miller, Cathy L.

2013-01-01

387

Dynamic shearing resistance of molten metal films under high pressures and extremely high shearing rates  

Microsoft Academic Search

In the present study plate-impact pressureshear experiments have been conducted to study the dynamic shearing resistance of\\u000a molten metal films at shearing rates of approximately 107 s?1. These molten films are generated by pressure-shear impact of relatively low melt-point metals such as 7075-T6 Al alloy with\\u000a high hardness and high flow-strength tool-steel plates. By employing high impact speeds and relatively

Makoto Okada; Nai-Shang Liou; Vikas Prakash

2002-01-01

388

High exposure rates of anticoagulant rodenticides in predatory bird species in intensively managed landscapes in Denmark.  

PubMed

The extensive use of anticoagulant rodenticides (ARs) for rodent control has led to widespread secondary exposure in nontarget predatory wildlife species. We investigated exposure rates and concentrations of five ARs in liver samples from five raptors and six owls from Denmark. A total of 430 birds were analysed. ARs were detected in 84-100 % of individual birds within each species. Multiple AR exposure was detected in 73 % of all birds. Average number of substances detected in individual birds was 2.2 with no differences between owls and raptors. Difenacoum, bromadiolone, and brodifacoum were the most prevalent substances and occurred in the highest concentrations. Second-generation ARs made up 96 % of the summed AR burden. Among the six core species (sample size >30), summed AR concentrations were lower in rough-legged buzzard (Buteo lagopus) and long-eared owl (Asio otus) than in barn owl (Tyto alba), buzzard (B. buteo), kestrel (Falco tinnunculus), and tawny owl (Strix aluco). There was a strong tendency for seasonal variations in the summed AR concentration with levels being lowest during autumn, which is probably related to an influx of less-exposed migrating birds from northern Scandinavia during autumn. High hepatic AR residue concentrations (>100 ng/g wet weight), which have been associated with symptoms of rodenticide poisoning and increased mortality, were recorded high frequencies (12.9-37.4 %) in five of the six core species. The results suggest that the present use of ARs in Denmark, at least locally, may have adverse effects on reproduction and, ultimately, population status in some raptors and owls. PMID:22588365

Christensen, Thomas Kjær; Lassen, Pia; Elmeros, Morten

2012-10-01

389

Life-history traits of Amur sleeper, Perccottus glenii , in the invaded Vistula River: early investment in reproduction but reduced growth rate  

Microsoft Academic Search

In recent decades, Amur sleeper is one of the most invasive fish species in Eastern and Central Europe. Generally, it is assumed\\u000a that success of an invasive species can largely depend on the plasticity of its life-history traits, e.g., indicated by higher\\u000a investment in reproduction in the initial stage of its invasion. On the other hand, such energy allocation to

Grabowska Joanna; Pietraszewski Dariusz; Przybylski Miros?aw; Tarkan Ali Serhan; Marsza? Lidia; Lampart-Ka?u?niacka Magdalena

2011-01-01

390

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.

Heinze, Jurgen; Schrempf, Alexandra

2012-01-01

391

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

392

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

393

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

394

ASIC for High Rate 3D Position Sensitive Detectors  

SciTech Connect

We report on the development of an application specific integrated circuit (ASIC) for 3D position sensitive detectors (3D PSD). The ASIC is designed to operate with pixelated wide bandgap sensors like Cadmium-Zinc-Telluride (CZT), Mercuric Iodide (Hgl2) and Thallium Bromide (TIBr). It measures the amplitudes and timings associated with an ionizing event on 128 anodes, the anode grid, and the cathode. Each channel provides low-noise charge amplification, high-order shaping with peaking time adjustable from 250 ns to 12 {micro}s, gain adjustable to 20 mV/fC or 120 mV/fC (for a dynamic range of 3.2 MeV and 530 keV in CZT), amplitude discrimination with 5-bit trimming, and positive and negative peak and timing detections. The readout can be full or sparse, based on a flag and single- or multi-cycle token passing. All channels, triggered channels only, or triggered with neighbors can be read out thus increasing the rate capability of the system to more than 10 kcps. The ASIC dissipates 330 mW which corresponds to about 2.5 mW per channel.

Vernon, E.; De Geronimo, G.; Ackley, K.; Fried, J.; He, Z.; Herman, C.; Zhang, F.

2010-06-16

395

Substrate inhibition and control for high rate biogas production  

SciTech Connect

This research addresses a critical aspect of the technical feasibility of biogas recovery with poultry manure using anaerobic digestion, namely, inhibition and toxicity factors limiting methane generation under high rate conditions. The research was designed to identify the limiting factors and to examine alternative pretreatment and in situ control methods for the anaerobic digestion of poultry manure as an energy producing system. Biogas production was indicated by the daily gas volume produced per unit digester capacity. Enhanced biogas generation from the anaerobic digester systems using poultry manure was studied in laboratory- and pilot-scale digester operations. It was found that ammonia nitrogen concentration above 4000 mg/l was inhibitory to biogas production. Pretreatment of the manure by elutriation was effective for decreasing inhibitory/toxic conditions. Increased gas production resulted without an indication of serious inhibition by increased volatile acids, indicating a limitation of available carbon sources. For poultry manure digestion, the optimum pH range was 7.1 to 7.6. Annual costs for pretreatment/biogas systems for 10,000, 30,000 and 50,000 birds were estimated and compared with annual surplus energy produced. The economic break-even point was achieved in digesters for greater than 30,000 birds. Capital cost of the digester system was estimated to be $18,300 with annual costs around $4000. It is anticipated that the digester system could be economically applied to smaller farms as energy costs increase.

Shin, H.S.

1982-01-01

396

Material failure modelling in metals at high strain rates  

NASA Astrophysics Data System (ADS)

Plate impact tests have been conducted on the OFHC Cu using single-stage gas gun. Using stress gauges, which were supported with PMMA blocks on the back of the target plates, stress-time histories have been recorded. After testing, micro structural observations of the softly recovered OFHC Cu spalled specimen were carried out and evolution of damage has been examined. To account for the physical mechanisms of failure, the concept that thermal activation in material separation during fracture processes has been adopted as basic mechanism for this material failure model development. With this basic assumption, the proposed model is compatible with the Mechanical Threshold Stress model and therefore in this development it was incorporated into the MTS material model in DYNA3D. In order to analyse proposed criterion a series of FE simulations have been performed for OFHC Cu. The numerical analysis results clearly demonstrate the ability of the model to predict the spall process and experimentally observed tensile damage and failure. It is possible to simulate high strain rate deformation processes and dynamic failure in tension for wide range of temperature. The proposed cumulative criterion, introduced in the DYNA3D code, is able to reproduce the ``pull-back'' stresses of the free surface caused by creation of the internal spalling, and enables one to analyse numerically the spalling over a wide range of impact velocities.

Panov, Vili

2005-07-01

397

Material Failure Modelling in Metals at High Strain Rates  

NASA Astrophysics Data System (ADS)

To account for the physical mechanisms of failure, the concept of thermal activation of damage and failure has been adopted as basis for this material model development. This basic assumption makes the proposed approach compatible with the Mechanical Threshold Stress (MTS) model, which was used as the strength part of the proposed constitutive model. The developments were incorporated into public domain DYNA3D. In order to validate the model, a series of FE simulations of plate impact experiments were performed for OFHC Cu. The numerical analysis results clearly demonstrate the ability of the model to predict the spall process and experimentally observed tensile damage and failure. The model allows simulation of high strain rate deformation processes and dynamic failure in tension for wide range of temperatures. The model is able to reproduce typical longitudinal stress reloading observed in plate impact tests, which is caused by the creation of the internal free surface. Plate impact tests used for model validation were performed on a single-stage gas gun. Longitudinal stresses were measured with stress gauges.

Panov, Vili; Vignjevic, Rade; Bourne, Neil; Millet, Jerremy

2006-07-01

398

The Dust Tail Striae of High Production Rate Comets  

NASA Astrophysics Data System (ADS)

Several high-production rate comets have displayed dust tails containing numerous striae - near-linear regions of enhanced brightness. These can be spectacular features, and in extreme cases such as C/2006 P1 (McNaught), even to the naked eye. It is widely accepted that striae formation is due to the fragmentation of cometary dust, but whether that fragmentation takes place in discrete events or as continuous cascades of fragmentation is currently unresolved. Our simulations of striae successfully reproduce many aspects of their morphology and dynamics. In the event of Comet C/2012 S1 (ISON) possessing striae, we present first results of the fitting of fragmentation scenarios to the observed tail features. We shall also present similar fits to striae in the tails of C/2002 V1 (NEAT) in January 2003, C/2006 P1 (McNaught) in January-February 2007, and C/2011 L4 (PANSTARRS) in March 2013. The implications of the model fits for the similarities and differences between the dust populations of these comets are presented.

Jones, G. H.; Birkett, K. S.; Ramanjooloo, Y.

2013-12-01

399

Accuracy of High-Rate GPS for Seismology  

NASA Technical Reports Server (NTRS)

We built a device for translating a GPS antenna on a positioning table to simulate the ground motions caused by an earthquake. The earthquake simulator is accurate to better than 0.1 mm in position, and provides the "ground truth" displacements for assessing the technique of high-rate GPS. We found that the root-mean-square error of the 1-Hz GPS position estimates over the 15-min duration of the simulated seismic event was 2.5 mm, with approximately 96% of the observations in error by less than 5 mm, and is independent of GPS antenna motion. The error spectrum of the GPS estimates is approximately flicker noise, with a 50% decorrelation time for the position error of approx.1.6 s. We that, for the particular event simulated, the spectrum of dependent error in the GPS measurements. surface deformations exceeds the GPS error spectrum within a finite band. More studies are required to determine whether a generally optimal bandwidth exists for a target group of seismic events.

Elosegui, P.; Davis, J. L.; Oberlander, D.; Baena, R.; Ekstrom, G.

2006-01-01

400

Cassini High Rate Detector V5.0  

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 the end of 2008. Please refer to Srama et al. (2004) for a detailed HRD description. --Apple-Mail-2--243167724 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit On Aug 5, 2008, at 1:54 PM, Carolyn Stern Grant wrote: >> I am preparing to send you a new batch of publications for >> inclusion in the ADS system. I notice that I never got a response >> from you to the following question. Should I send the publications >> in >> the format we have used in the past, or would you like us to change >> our software to fix this problem? (see your earlier message >> attached.) > > Hi Carol, > > Go ahead and use the format you've used in the past. > > Thanks, > -Carolyn > ************************************************************************* > Carolyn Stern Grant Astrophysics Data System (ADS) > stern@cfa.harvard.edu Center for Astrophysics > 617-495-7154 (voicemail) 60 Garden Street MS 67 > 617-495-7356 fax Cambridge, MA 02138 > ************************************************************************* > > --Apple-Mail-2--243167724--

Economou, T.; Didonna, P.

2009-06-01

401

High-Rate Anaerobic Treatment of Wastewater at Low Temperatures  

PubMed Central

Anaerobic treatment of a volatile fatty acid (VFA) mixture was investigated under psychrophilic (3 to 8°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°C.

Lettinga, Gatze; Rebac, Salih; Parshina, Sofia; Nozhevnikova, Alla; van Lier, Jules B.; Stams, Alfons J. M.

1999-01-01

402

Potential biogas scrubbing using a high rate pond.  

PubMed

The potential to scrub biogas in a high rate pond (HRP) was evaluated using apparatus designed to maximize gas-liquid contact. Experiments compared the removal of carbon dioxide from synthetic biogas by an "in-pond angled gutter" to that by a simulated "counter-current pit." Results showed that the counter current pit has potential for use in biogas scrubbing, with synthetic biogas carbon dioxide composition consistently reduced from 40% to < 5%. The in-pond angled gutter was less effective due to bubble coalescence which reduced the total bubble surface area available for gas transfer. Measurement of oxygen levels in the scrubbed biogas showed that despite supersaturation of oxygen in the HRP water, there was little transfer to the biogas, so that explosive methane/oxygen mixtures would not be formed. Theoretical calculations indicated that the amount of biogas likely to be formed during anaerobic treatment of municipal wastewater could be scrubbed in the HRP of the same advanced pond system with little influence on HRP pH, algal growth and treatment performance. These encouraging results justify further research on this method of biogas purification. PMID:16114691

Mandeno, G; Craggs, R; Tanner, C; Sukias, J; Webster-Brown, J

2005-01-01

403

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

404

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

405

Reproductive biology of seals.  

PubMed

The reproductive biology of seals is fascinating in many aspects. As in most mammals, the time of onset of puberty in seals is variable. Once sexually mature, most but not all seals are seasonally mono-oestrous, with highly synchronized breeding seasons. They have evolved as either terrestrial or aquatic copulators, although a few species mate in a variety of habitats. Their mating strategies are diverse, ranging from serial monogamy to extreme polygyny. Gestation in seals is characterized by an embryonic diapause, which is obligate in most species. Reactivation of the blastocyst is followed by a placental gestation. All species of seal require a terrestrial (including ice floes) habitat for parturition. Lactation differs between the two seal families: phocid seals have an intense period of maternal investment, during which the mothers fast; otariid seals have a prolonged lactation during which intense bouts of suckling are interspersed by days of separation from their pups while the mother forages at sea. Although the anatomy and functional morphology of seals has been well described, less is known of the endocrinology of reproduction. This is due mainly to the logistical difficulties that researchers experience in collecting serial samples from a species that is relatively difficult to handle. This article reviews the basic anatomy and physiology, and our current understanding of the comparative aspects of reproduction in seals. Reproductive behaviours as well as the influences of environmental factors, such as photoperiod, nutrition and xenobiotics, are also discussed. PMID:9414481

Atkinson, S

1997-09-01

406

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

407

A forward error correction technique using a high-speed, high-rate single chip codec  

NASA Technical Reports Server (NTRS)

The authors describe an error-correction coding approach that allows operation in either burst or continuous modes at data rates of multiple hundreds of megabits per second. Bandspreading is low since the code rate is 7/8 or greater, which is consistent with high-rate link operation. The encoder, along with a hard-decision decoder, fits on a single application-specific integrated circuit (ASIC) chip. Soft-decision decoding is possible utilizing applique hardware in conjunction with the hard-decision decoder. Expected coding gain is a function of the application and is approximately 2.5 dB for hard-decision decoding at 10-5 bit-error rate with phase-shift-keying modulation and additive Gaussian white noise interference. The principal use envisioned for this technique is to achieve a modest amount of coding gain on high-data-rate, bandwidth-constrained channels. Data rates of up to 300 Mb/s can be accommodated by the codec chip. The major objective is burst-mode communications, where code words are composed of 32 n data bits followed by 32 overhead bits.

Boyd, R. W.; Hartman, W. F.; Jones, Robert E.

1989-01-01

408

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

409

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 ...

410

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

411

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

412

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

413

Transistor reset preamplifier for high-rate high-resolution spectroscopy  

SciTech Connect

Pulsed transistor reset of high resolution charge sensitive preamplifiers used in cooled semiconductor spectrometers can sometimes have an advantage over pulsed light reset systems. Several versions of transistor reset spectrometers using both silicon and germanium detectors have been built. This paper discusses the advantages of the transistor reset system and illustrates several configurations of the packages used for the FET and reset transistor. It also describes the preamplifer circuit and shows the performance of the spectrometer at high rates.

Landis, D.A.; Cork, C.P.; Madden, N.W.; Goulding, F.S.

1981-10-01

414

High temperature deformation and fracture behaviour of 316L stainless steel under high strain rate loading  

NASA Astrophysics Data System (ADS)

The high temperature deformation and fracture behaviour of 316L stainless steel under high strain rate loading conditions are investigated by means of a split Hopkinson pressure bar. Impact tests are performed at strain rates ranging from 1 × 10 3 s -1 to 5 × 10 3 s -1 and temperatures between 25 °C and 800 °C. The experimental results indicate that the flow response and fracture characteristics of 316L stainless steel are significantly dependent on the strain rate and temperature. The fracture analysis results indicate that the 316L specimens fail predominantly as the result of intensive localised shearing. Furthermore, it is shown that the flow localisation effect leads to the formation of adiabatic shear bands. The fracture surfaces of the deformed 316L specimens are characterised by a dimple-like structure with knobby features. The knobby features are thought to be the result of a rise in the local temperature to a value greater than the melting point.

Lee, Woei-Shyan; Lin, Chi-Feng; Chen, Tao-Hsing; Luo, Wen-Zhen

2012-01-01

415

Modeling the concentration-response function of the herbicide dinoseb on Daphnia magna (survival time, reproduction) and Pseudokirchneriella subcapitata (growth rate).  

PubMed

Models describing dose-response relationships are becoming increasingly popular in ecotoxicology. They allow simple and thorough evaluations of toxicity test results, including inter- and extrapolations to concentrations or exposure times other than those tested. Simple parametric regression models are of particular interest because their parameters may be attributed mechanistic meanings and they can be applied without sophisticated mathematical and computational support. We recently proposed a four-parameter logistic regression model to fit the survival data of Daphnia magna under dinoseb stress. The model parameters are the maximum survival time, the minimum time required for an individual to die, effect concentration, EC(50), and a curve shape parameter. This model has now been applied to compare the lethality and reproduction toxicity of D. magna and the growth inhibition of Pseudokirchneriella subcapitata under dinoseb stress. It can be fitted adequately to all the measured data and the parameters can be attributed biological meanings in any of the three endpoints. A comparison of the modeled concentration-response functions of all three endpoints for dinoseb toxicity shows that the range of ECs with respect to both D. magna and algae is steep (a decrease of between 0.1 and 0.6 mg/L). The survival and reproduction of D. magna exhibit similar characteristic concentration-response functions and toxicities. The statistical no-effect concentration (SNEC) is 0.14 (survival) and 0.11 (reproduction)mg/L, respectively. On the other hand, algae seem to be less sensitive to dinoseb than D. magna (SNEC: 0.48 mg/L). However, further investigations of individual algae may lead to a more suitable comparison. We speculate that the four parameters of the model function can be related to specific properties of chemicals and organisms. Characterization of these properties would allow simple and appropriate estimation of the toxic effects of these chemicals. PMID:15978287

Chèvre, Nathalie; Brazzale, Alessandra R; Becker-van Slooten, Kristin; Behra, Renata; Tarradellas, Joseph; Guettinger, Herbert

2005-09-01

416

A charge sensitive preamplifier for high peak stability in spectroscopic measurements at high counting rates  

Microsoft Academic Search

In this work a charge preamplifier designed to achieve high stability in spectroscopic measurements at different counting rates is presented. The preamplifier operates with the input JFET and the feedback capacitor directly integrated on the detector, in the specific case a silicon drift detector (SDD). The motivation of the work is to overcome the peak shift, typically in the order

C. Fiorini

2004-01-01

417

A charge sensitive preamplifier for high peak stability in spectroscopic measurements at high counting rates  

Microsoft Academic Search

In this paper, a charge preamplifier designed to achieve high stability in spectroscopic measurements at different counting rates is presented. The preamplifier operates with the input JFET and the feedback capacitor directly integrated on the silicon detector, in the specific case a Silicon Drift Detector (SDD). The motivation of the work is to overcome the peak shift, typically in the

Carlo Fiorini

2005-01-01

418

High Rate, Low Temperature Testing and Modeling of Water Ice for High Speed Ballistic Probes  

NASA Astrophysics Data System (ADS)

High rate, low temperature testing and modeling of water ice is important in design of ballistic probes for in-situ evaluation of icy moon composition. The results of coupon and impact testing will be presented, as well as a new modeling approach.

Kohlman, L. W.; Li, B.; Prakash, V.; Pereira, J. M.; Carney, K. S.; Revilock, D. M.; Ruggeri, C. R.; Lawrence, C.; Wu, X.

2014-06-01

419

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

420

Mode locking of fiber lasers at high repetition rates  

NASA Astrophysics Data System (ADS)

Mode-locked fiber lasers have become indispensable tools in many fields as their use is no longer relegated to the optics community. In the future, their size will decrease and their applications will become far more prevalent than they are today. At present, the field is undergoing a cardinal shift as these devices have become commercially available in the last decade. This has put an emphasis on long-term performance and reliability as these devices are beginning to be integrated into complex systems in areas as diverse as medical optics, micro-machining, forensics, and tracking as well as their obvious use as laboratory tools or sources in telecommunications. This is also resulting in a transition from research to engineering. Since the field of mode-locked lasers has been extensively studied for over forty years, one may expect that little has been overlooked. However, since the mode-locking phenomena is governed by nonlinear partial differential equations, a rich degree of effects exist and the field has not yet been exhausted. During the past two decades, the main emphasis has been on short-pulse generation; however, the main thrust of research is likely to change to producing high-power devices, which will result in limiting effects and thermal issues that are currently ignored for low-power sources. Finally, detailed studies have generally been performed numerically as analytic solutions only exist in limiting cases. In this thesis, mode-locked fiber lasers are studied experimentally, numerically, and theoretically. The experimental work focuses on high-repetition rate, mode-locked cavities, which are then modeled numerically. A semi-analytic tool, which goes beyond the prior theories and includes all of the effects experienced by steady-state, mode-locked pulses as they propagate in a laser cavity, is also derived. The only caveats to this approach are an assumption of the pulse shape and the requirement that it not change during propagation through the laser cavity. Despite these limitations, it is found that the parameters predicted by our method deviate from those found through rigorous numerical simulations by 10% or less.

Usechak, Nicholas G.

421

High Rate and High Capacity Li-Ion Electrodes for Vehicular Applications  

SciTech Connect

Significant advances in both energy density and rate capability for Li-ion batteries are necessary for implementation in electric vehicles. We have employed two different methods to improve the rate capability of high capacity electrodes. For example, we previously demonstrated that thin film high volume expansion MoO{sub 3} nanoparticle electrodes ({approx}2 {micro}m thick) have a stable capacity of {approx}630 mAh/g, at C/2 (charge/dicharge in 2 hours). By fabricating thicker conventional electrodes, an improved reversible capacity of {approx}1000 mAh/g is achieved, but the rate capability decreases. To achieve high-rate capability, we applied a thin Al{sub 2}O{sub 3} atomic layer deposition coating to enable the high volume expansion and prevent mechanical degradation. Also, we recently reported that a thin ALD Al{sub 2}O{sub 3} coating can enable natural graphite (NG) electrodes to exhibit remarkably durable cycling at 50 C. Additionally, Al{sub 2}O{sub 3} ALD films with a thickness of 2 to 4 {angstrom} have been shown to allow LiCoO{sub 2} to exhibit 89% capacity retention after 120 charge-discharge cycles performed up to 4.5 V vs. Li/Li{sup +}. Capacity fade at this high voltage is generally caused by oxidative decomposition of the electrolyte or cobalt dissolution. We have recently fabricated full cells of NG and LiCoO{sub 2} and coated both electrodes, one or the other electrode as well as neither electrode. In creating these full cells, we observed some surprising results that lead us to obtain a greater understanding of the ALD coatings. In a different approach we have employed carbon single-wall nanotubes (SWNTs) to synthesize binder-free, high-rate capability electrodes, with 95 wt.% active materials. In one case, Fe{sub 3}O{sub 4} nanorods are employed as the active storage anode material. Recently, we have also employed this method to demonstrate improved conductivity and highly improved rate capability for a LiNi{sub 0.4}Mn{sub 0.4}Co{sub 0.2}O{sub 2} cathode material. Raman spectroscopy was employed to understand how the SWNTs function as a highly flexible conductive additive.

Dillon, A. C.

2012-01-01

422

High-quality embryos maintain high pregnancy rates in passive smokers but not in active smokers.  

PubMed

This study assesses the effect of passive and active smoking on pregnancy rates after IVF with transfer of high-quality embryos. In a cohort study, women attending the IVF unit in 2006–2007 with favourable parameters for pregnancy (<38 years; less than three IVF cycles, transfer of two highest-grade embryos) grouped by smoking status were included. The cohort included 237 patients/cycles: 42 smokers, 195 non-smokers. The clinical pregnancy rate was significantly lower in smokers (35.7% versus 55.4%,P = 0.021, OR = 0.44 (95% CI 0.22–0.89)), even after conditional stratification on covariates (passive smoker, passive or partner smoker, age group). The live-birth rate was lower in smokers (28.6% versus 42.6%), but the difference was not statistically significant(OR = 0.54 (0.26–1.11)). Among non-smokers, there was no difference in pregnancy rate by passive or partner smoking. On logistic regression, variables predicting pregnancy were age <35 years (P = 0.008, OR = 2.58 (1.2–5.2)) and non-smoking (P = 0.003,OR = 3.47 (1.51–7.98)). In conclusion, transfer of high-quality embryos does not overcome the negative effect of active smoking on pregnancy rate in IVF treatment. The endometrium is apparently involved in the mechanism underlying IVF failure in smokers. PMID:21115271

Ben-Haroush, Avi; Ashkenazi, Jacob; Sapir, Onit; Pinkas, Haim; Fisch, Benjamin; Farhi, Jacob

2011-01-01

423

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

424

Dairy cows' reproductive response to feeding level differs according to the reproductive stage and the breed.  

PubMed

Reproductive performance has decreased over the last decades in many dairy systems. This study aimed at comparing the effects of a high- and a low-feeding level on reproductive stages (cyclicity, oestrus and fertility) of Holstein and Normande cows in a grass-based winter compact calving system. High-fed cows received a total mixed ration composed of 55% maize silage, 15% dehydrated alfalfa pellets and 30% concentrate in winter and 4 kg/day concentrate supply at grazing. Low-fed cows only received 50% grass silage and 50% haylage in winter and no concentrate at grazing. Low-fed cows produced less milk over 44 weeks, but lost more body condition (BC) than high-fed ones (5207 v. 7457 kg, -1.28 v. -0.96 unit, P < 0.001). Normande cows produced less milk and lost less BC than Holstein ones (5596 v. 7068 kg, -0.89 v. -1.36 unit, P < 0.001). Post-partum ovarian activity was little affected by the feeding level. In both breeds, ovulation detection rate was higher in low-fed cows (74% v. 59%, P < 0.001) and detection relied more frequently on standing behaviour (67% v. 55%, P = 0.022). In both breeds, the recalving rate following the first and second inseminations was not significantly affected by the feeding level, although more non-fertilisations or early embryo mortalities occurred in low-fed cows (43% v. 26%, P = 0.004). For the Holstein breed, this was clearly explained by more late embryo mortalities in high-fed cows (30% v. 9%, P = 0.004). Finally, pregnancy rate by the end of the 13-week breeding period was similar between feeding groups. Conversely, the Normande dual-purpose cows had a higher pregnancy rate by the end of the breeding period than the Holstein dairy cows (72% v. 54%, P = 0.007), owing to a better ovarian activity (79% v. 54% normal, P < 0.001) and a higher recalving rate following insemination (53% v. 37%, P = 0.007). In conclusion, this study demonstrates that feeding levels with converse effects on milk yield and BC score also have converse effects on reproductive stages and lead to quite similar final reproductive performance in compact calving systems. Normande cows benefit from an overall better reproductive performance, but do not suit high feeding levels for very compact calving systems owing to depressed oestrous behaviour. PMID:22439995

Cutullic, E; Delaby, L; Gallard, Y; Disenhaus, C

2011-04-01

425

High rate discharge characteristics of Li\\/SOCl2 cells  

Microsoft Academic Search

The performance characteristics of the Li\\/SOCl2 cell have been determined as a function of discharge rate, electrolyte composition, cathode thickness, and cell temperature. Cells have been discharged at rates ranging from about 3 to nearly 300 mA\\/sq cm. Cathodes with electolyte solutions have contained either LiAlCl4 or AlCl3, with the most efficient discharge characteristics being realized with 1.5M LiAlCl4 and

K. A. Klinedinst; M. J. Domeniconi

1980-01-01

426

A high resolution study of forsterite dissolution rates  

Microsoft Academic Search

The rates of dissolution of olivine (Fo92) were measured over the pH range of 1.8 to 3.8 and from 25 to 45°C using an externally recycled mixed flow reactor. The data were filtered to remove several sources of systematic errors including non-steady state measurements, solution concentrations that were less than 50% above the detection limit, and Mg\\/Si rate ratios 40%

Jodi J. Rosso; J. Donald Rimstidt

2000-01-01

427

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

428

High dose rate brachytherapy in the treatment of prostate cancer.  

PubMed

The optimal treatment of patients with localized prostate cancer remains controversial. Significant clinical data are available, however, demonstrating that patients treated with radiation therapy (RT) have a significantly better outcome as the dose to the gland is increased. What remains debatable, however, is how to best deliver these higher doses of RT without significantly increasing normal tissue toxicities. Conformal high dose rate brachytherapy (C-HDR BT) represents an alternative means of precise dose delivery that offers similar tumoricidal effects as three-dimensional (3D) conformal external beam radiotherapy (EBRT) or permanent interstitial prostate seed implants with potential additional advantages. Since C-HDR BT consists of temporarily placing afterloading needles or catheters directly into the prostate gland under real-time ultrasound guidance, a steep dose gradient between the prostate and adjacent normal tissues can be generated that is minimally affected by organ motion and edema or treatment setup uncertainties. The ability to control the amount of time the single HDR radioactive source "dwells" at each position along the length of each brachytherapy catheter further enhances the conformity of the dose. In addition, recent radiobiological data on prostate cancer treatment suggest that C-HDR BT should produce tumor control and late normal tissue side effects that are at least as good as achieved with conventional fractionation, with the additional possibility that acute side effects might be reduced. Published data from several groups performing C-HDR BT as boosts in patients with locally advanced disease have supported these assumptions. Combined with the physical advantages discussed above, C-HDR BT should provide similar tumor control as 3D conformal EBRT with the added advantages of reduced treatment times, less acute toxicity, and no additional technological requirements to account and correct for treatment setup uncertainties and organ motion. Due to the success of C-HDR BT as boost treatment in locally advanced disease, this form of radiation treatment has recently been applied to low-risk prostate cancer patients as an alternative brachytherapy technique to permanent interstitial seed implantation. Advantages in this setting include an improved ability to define and deliver the prescribed dose, a significantly shortened treatment schedule compared to 3D conformal EBRT, and the fact that patients are not radioactive after implantation. PMID:12905008

Vicini, Frank; Vargas, Carlos; Gustafson, Gary; Edmundson, Gregory; Martinez, Alvaro

2003-09-01

429

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.

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

430

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,