Age-Related Changes in Locomotor Performance Reveal a Similar Pattern for Caenorhabditis elegans, Mus domesticus, Canis familiaris, Equus caballus, and Homo sapiens.

Science.gov (United States)

Marck, Adrien; Berthelot, Geoffroy; Foulonneau, Vincent; Marc, Andy; Antero-Jacquemin, Juliana; Noirez, Philippe; Bronikowski, Anne M; Morgan, Theodore J; Garland, Theodore; Carter, Patrick A; Hersen, Pascal; Di Meglio, Jean-Marc; Toussaint, Jean-François

2017-04-01

Locomotion is one of the major physiological functions for most animals. Previous studies have described aging mechanisms linked to locomotor performance among different species. However, the precise dynamics of these age-related changes, and their interactions with development and senescence, are largely unknown. Here, we use the same conceptual framework to describe locomotor performances in Caenorhabditis elegans, Mus domesticus, Canis familiaris, Equus caballus, and Homo sapiens. We show that locomotion is a consistent biomarker of age-related changes, with an asymmetrical pattern throughout life, regardless of the type of effort or its duration. However, there is variation (i) among species for the same mode of locomotion, (ii) within species for different modes of locomotion, and (iii) among individuals of the same species for the same mode of locomotion. Age-related patterns are modulated by genetic (such as selective breeding) as well as environmental conditions (such as temperature). However, in all cases, the intersection of the rising developmental phase and the declining senescent phase reveals neither a sharp transition nor a plateau, but a smooth transition, emphasizing a crucial moment: the age at peak performance. This transition may define a specific target for future investigations on the dynamics of such biological interactions. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Characterization of a Full-Length Endogenous Beta-Retrovirus, EqERV-Beta1, in the Genome of the Horse (Equus caballus

Directory of Open Access Journals (Sweden)

Antoinette C. van der Kuyl

2011-06-01

Full Text Available Information on endogenous retroviruses fixed in the horse (Equus caballus genome is scarce. The recent availability of a draft sequence of the horse genome enables the detection of such integrated viruses by similarity search. Using translated nucleotide fragments from gamma-, beta-, and delta-retroviral genera for initial searches, a full-length beta-retrovirus genome was retrieved from a horse chromosome 5 contig. The provirus, tentatively named EqERV-beta1 (for the first equine endogenous beta-retrovirus, was 10434 nucleotide (nt in length with the usual retroviral genome structure of 5’LTR-gag-pro-pol-env-3’LTR. The LTRs were 1361 nt long, and differed approximately 1% from each other, suggestive of a relatively recent integration. Coding sequences for gag, pro and pol were present in three different reading-frames, as common for beta-retroviruses, and the reading frames were completely open, except that the env gene was interrupted by a single stopcodon. No reading frame was apparent downstream of the env gene, suggesting that EqERV-beta1 does not encode a superantigen like mouse mammary tumor virus (MMTV. A second proviral genome of EqERV-beta1, with no stopcodon in env, is additionally integrated on chromosome 5 downstream of the first virus. Single EqERV-beta1 LTRs were abundantly present on all chromosomes except chromosome 24. Phylogenetically, EqERV-beta1 most closely resembles an unclassified retroviral sequence from cattle (Bos taurus, and the murine beta-retrovirus MMTV.

Short Communication Quick method for identifying horse (Equus caballus) and donkey (Equus asinus) hybrids.

Science.gov (United States)

Franco, M M; Santos, J B F; Mendonça, A S; Silva, T C F; Antunes, R C; Melo, E O

2016-09-23

The domestication of the Equus genus 5000-6000 years ago has influenced the history of human civilization. As soon as horse and donkey species had been domesticated, they were crossbred, producing humanity's first documented attempt at animal genome manipulation. Since then, the mule (male donkey x female horse) and the reciprocal cross (the hinny, male horse x female donkey) have been the most common equine hybrids in the world. Due to their hybrid vigor, mules and hinnies have been intensively used for carrying loads and people and for tilling the land. Despite their importance, visual distinction of mules and hinnies is difficult due to high phenotypic resemblance. However, the distinction between these two hybrids is of pivotal importance for equid breeders and ranchers. In this study, an easy, low-cost, effective, and fast multiplex-polymerase chain reaction method was developed to distinguish the maternal origin of mules and hinnies, targeting the hyper-variable mitochondrial DNA D-loop region. This methodology can help breeders, ranchers, animal science professionals, and researchers manage their equine herds with more confidence and precision.

Practical Bias Correction in Aerial Surveys of Large Mammals: Validation of Hybrid Double-Observer with Sightability Method against Known Abundance of Feral Horse (Equus caballus) Populations.

Science.gov (United States)

Lubow, Bruce C; Ransom, Jason I

2016-01-01

Reliably estimating wildlife abundance is fundamental to effective management. Aerial surveys are one of the only spatially robust tools for estimating large mammal populations, but statistical sampling methods are required to address detection biases that affect accuracy and precision of the estimates. Although various methods for correcting aerial survey bias are employed on large mammal species around the world, these have rarely been rigorously validated. Several populations of feral horses (Equus caballus) in the western United States have been intensively studied, resulting in identification of all unique individuals. This provided a rare opportunity to test aerial survey bias correction on populations of known abundance. We hypothesized that a hybrid method combining simultaneous double-observer and sightability bias correction techniques would accurately estimate abundance. We validated this integrated technique on populations of known size and also on a pair of surveys before and after a known number was removed. Our analysis identified several covariates across the surveys that explained and corrected biases in the estimates. All six tests on known populations produced estimates with deviations from the known value ranging from -8.5% to +13.7% and corrected by our statistical models. Our results validate the hybrid method, highlight its potentially broad applicability, identify some limitations, and provide insight and guidance for improving survey designs.

Zonadhesin D3-polypeptides vary among species but are similar in Equus species capable of interbreeding.

Science.gov (United States)

Tardif, Steve; Brady, Heidi A; Breazeale, Kelly R; Bi, Ming; Thompson, Leslie D; Bruemmer, Jason E; Bailey, Laura B; Hardy, Daniel M

2010-02-01

Zonadhesin is a rapidly evolving protein in the sperm acrosome that confers species specificity to sperm-zona pellucida adhesion. Though structural variation in zonadhesin likely contributes to its species-specific function, the protein has not previously been characterized in organisms capable of interbreeding. Here we compared properties of zonadhesin in several animals, including the horse (Equus caballus), donkey (E. asinus), and Grevy's zebra (E. grevyi) to determine if variation in zonadhesin correlates with ability of gametes to cross-fertilize. Zonadhesin localized to the apical acrosomes of spermatozoa from all three Equus species, similar to its localization in other animals. Likewise, in horse and donkey testis, zonadhesin was detected only in germ cells, first in the acrosomal granule of round spermatids and then in the developing acrosomes of elongating spermatids. Among non-Equus species, D3-domain polypeptides of mature, processed zonadhesin varied markedly in size and detergent solubility. However, zonadhesin D3-domain polypeptides in horse, donkey, and zebra spermatozoa exhibited identical electrophoretic mobility and detergent solubility. Equus zonadhesin D3-polypeptides (p110/p80 doublet) were most similar in size to porcine and bovine zonadhesin D3-polypeptides (p105). Sequence comparisons revealed that the horse zonadhesin precursor's domain content and arrangement are similar to those of zonadhesin from other large animals. Partial sequences of horse and donkey zonadhesin were much more similar to each other (>99% identity) than they were to orthologous sequences of human, pig, rabbit, and mouse zonadhesin (52%-72% identity). We conclude that conservation of zonadhesin D3-polypeptide properties correlates with ability of Equus species to interbreed.

Zonadhesin D3-Polypeptides Vary among Species but Are Similar in Equus Species Capable of Interbreeding1

Science.gov (United States)

Tardif, Steve; Brady, Heidi A.; Breazeale, Kelly R.; Bi, Ming; Thompson, Leslie D.; Bruemmer, Jason E.; Bailey, Laura B.; Hardy, Daniel M.

2009-01-01

Zonadhesin is a rapidly evolving protein in the sperm acrosome that confers species specificity to sperm-zona pellucida adhesion. Though structural variation in zonadhesin likely contributes to its species-specific function, the protein has not previously been characterized in organisms capable of interbreeding. Here we compared properties of zonadhesin in several animals, including the horse (Equus caballus), donkey (E. asinus), and Grevy's zebra (E. grevyi) to determine if variation in zonadhesin correlates with ability of gametes to cross-fertilize. Zonadhesin localized to the apical acrosomes of spermatozoa from all three Equus species, similar to its localization in other animals. Likewise, in horse and donkey testis, zonadhesin was detected only in germ cells, first in the acrosomal granule of round spermatids and then in the developing acrosomes of elongating spermatids. Among non-Equus species, D3-domain polypeptides of mature, processed zonadhesin varied markedly in size and detergent solubility. However, zonadhesin D3-domain polypeptides in horse, donkey, and zebra spermatozoa exhibited identical electrophoretic mobility and detergent solubility. Equus zonadhesin D3-polypeptides (p110/p80 doublet) were most similar in size to porcine and bovine zonadhesin D3-polypeptides (p105). Sequence comparisons revealed that the horse zonadhesin precursor's domain content and arrangement are similar to those of zonadhesin from other large animals. Partial sequences of horse and donkey zonadhesin were much more similar to each other (>99% identity) than they were to orthologous sequences of human, pig, rabbit, and mouse zonadhesin (52%–72% identity). We conclude that conservation of zonadhesin D3-polypeptide properties correlates with ability of Equus species to interbreed. PMID:19794156

Variation in skin surface lipid composition among the Equidae.

Science.gov (United States)

Colton, S W; Downing, D T

1983-01-01

Skin surface lipids from Equus caballus, E. przewalskii, E. asinus, E. grevyi, E. hemionus onager and a mule (E. asinus/E. caballus) were analyzed in detail. In all species the surface lipid mixtures consisted of giant-ring lactones, cholesterol, cholesteryl esters and minor amounts of wax diesters. In E. caballus, the lactone hydroxyacids were entirely branched chained, while in E. asinus and E. grevyi they were almost exclusively straight chained. In E. przewalskii, the onager and the mule there were both straight and branched chain hydroxyacid lactones. These results are in harmony with published interpretations of the evolutionary relationships among Equus species.

INLUÊNCIA DO TEMPO DE DESCANSO “ANTE MORTEM” E DIETA DE MELAÇO SOBRE OS NÍVEIS DE GLICOGÊNIO MUSCULAR NA CARNE DE EQÜINOS (Equus caballus INFLUENCE OF “ANTE MORTEM” RESTING TIME AND MOLASSES DIET UPON MUSCULAR GLYCOGEN LEVELS IN EQUINES MEAT (Equus caballus

Directory of Open Access Journals (Sweden)

César Augusto Garcia

2007-09-01

Full Text Available

Foram coletadas 48 amostras de músculos tríceps braquial e bíceps femural de vinte e quatro eqüinos machos, sem raça definida, adultos e com pesos aproximadamente iguais. Antes do abate, os animais foram divididos em seis lotes que tiveram descanso ante mortem de zero, seis, quatorze, dezoito e vinte e quatro horas respectivamente. O lote de animais que descansou por dezoito horas foi subdividido em dois sublotes, sendo que um deles recebeu dieta de solução aquosa a 5% de melaço. Todos os outros animais só receberam água e ficaram em jejum. Não se observou influência sobre o pH. O glicogênio foi dosado pelos métodos de Pfluger e Nelson. O lote que apresentou menores índices de glicogênio foi o que descansou por zero hora, enquanto que o lote que apresentou maiores índices de glicogênio foi o que descansou por vinte e quatro horas.

Influence of “ante mortem” resting time and molasses diet upon muscular glycogen levels in equines meat (Equus caballus were studied. Forty-eight samples of triceps brachial and biceps femoral muscles of twenty-four adults and hybrids equines with approximately the same weights were analyzed. The animals were divided before death, in six groups with “ante mortem” resting time of zero, six, fourteen, eighteen and twenty-four hours, respectively. The animal groups with eighteen hours of rest were divided in two sub-groups and one received water solution with 5% of molasses. Alteration in pH levels were not observed. The glycogen was measured by Pfluger and Nelson’s methods. The group with smaller glycogen level was the group with zero hour of “ante mortem” rest, while the group with higher glycogen levels was the group with twenty-four hours of rest.

Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse.

Science.gov (United States)

Orlando, Ludovic; Ginolhac, Aurélien; Zhang, Guojie; Froese, Duane; Albrechtsen, Anders; Stiller, Mathias; Schubert, Mikkel; Cappellini, Enrico; Petersen, Bent; Moltke, Ida; Johnson, Philip L F; Fumagalli, Matteo; Vilstrup, Julia T; Raghavan, Maanasa; Korneliussen, Thorfinn; Malaspinas, Anna-Sapfo; Vogt, Josef; Szklarczyk, Damian; Kelstrup, Christian D; Vinther, Jakob; Dolocan, Andrei; Stenderup, Jesper; Velazquez, Amhed M V; Cahill, James; Rasmussen, Morten; Wang, Xiaoli; Min, Jiumeng; Zazula, Grant D; Seguin-Orlando, Andaine; Mortensen, Cecilie; Magnussen, Kim; Thompson, John F; Weinstock, Jacobo; Gregersen, Kristian; Røed, Knut H; Eisenmann, Véra; Rubin, Carl J; Miller, Donald C; Antczak, Douglas F; Bertelsen, Mads F; Brunak, Søren; Al-Rasheid, Khaled A S; Ryder, Oliver; Andersson, Leif; Mundy, John; Krogh, Anders; Gilbert, M Thomas P; Kjær, Kurt; Sicheritz-Ponten, Thomas; Jensen, Lars Juhl; Olsen, Jesper V; Hofreiter, Michael; Nielsen, Rasmus; Shapiro, Beth; Wang, Jun; Willerslev, Eske

2013-07-04

The rich fossil record of equids has made them a model for evolutionary processes. Here we present a 1.12-times coverage draft genome from a horse bone recovered from permafrost dated to approximately 560-780 thousand years before present (kyr BP). Our data represent the oldest full genome sequence determined so far by almost an order of magnitude. For comparison, we sequenced the genome of a Late Pleistocene horse (43 kyr BP), and modern genomes of five domestic horse breeds (Equus ferus caballus), a Przewalski's horse (E. f. przewalskii) and a donkey (E. asinus). Our analyses suggest that the Equus lineage giving rise to all contemporary horses, zebras and donkeys originated 4.0-4.5 million years before present (Myr BP), twice the conventionally accepted time to the most recent common ancestor of the genus Equus. We also find that horse population size fluctuated multiple times over the past 2 Myr, particularly during periods of severe climatic changes. We estimate that the Przewalski's and domestic horse populations diverged 38-72 kyr BP, and find no evidence of recent admixture between the domestic horse breeds and the Przewalski's horse investigated. This supports the contention that Przewalski's horses represent the last surviving wild horse population. We find similar levels of genetic variation among Przewalski's and domestic populations, indicating that the former are genetically viable and worthy of conservation efforts. We also find evidence for continuous selection on the immune system and olfaction throughout horse evolution. Finally, we identify 29 genomic regions among horse breeds that deviate from neutrality and show low levels of genetic variation compared to the Przewalski's horse. Such regions could correspond to loci selected early during domestication.

Konik - taaselustatud tarpan / Ingrid Randlaht

Index Scriptorium Estoniae

Randlaht, Ingrid

2011-01-01

Koniku (equus caballus ferus) tagasiaretusprojektidest 19. sajandil looduses väljasurnud ulukhobuse tarpanite (equus ferus ferus) suunal. Kinnikasvamise tõttu hävinenud elupaikade ja looduskeskkondade taastamisesst Euroopas - Lätis, Poolas, Hollandis - ulukhobuste ja ka veiste ning punahirvedega

Gene : CBRC-TTRU-01-0332 [SEVENS

Lifescience Database Archive (English)

Full Text Available 2| PREDICTED: similar to vomeronasal 1 receptor, k1 [Equus caballus] 5e-51 40% MTEVWSSLDCCTKFLRIRYSTVTILEIFF...LKPQTSTCVLPSFLFFWVINMLICIWIITNNETVTNASAAQPGYSPVYCKTKRGDYRESAVFQSAMLIRVFLCINLTVWTS

Gene : CBRC-MMUR-01-1612 [SEVENS

Lifescience Database Archive (English)

Full Text Available 1e-56 41% ref|XP_001497978.2| PREDICTED: similar to seven transmembrane helix receptor [Equus caballus] 5e-6...IPPVLRLACADTTEVEAIVFSSSALLILFTVMVILLSYAYILVTICSMRSLEAQGKALSTCASHLTIICLFYGTITFMYAQPSSHNSMEQNKVVSVVYTVVIPMLNPLIYSLRNKDVKHALKRRCQGKLPS ...

The prevalence and transmission to exotic equids (Equus quagga antiquorum, Equus przewalskii, Equus africanus) of intestinal nematodes in contaminated pasture in two wild animal parks.

Science.gov (United States)

Epe, C; Kings, M; Stoye, M; Böer, M

2001-06-01

Wild equids maintained in large enclosures may suffer from helminth diseases because common hygiene practices have only limited effects on parasite populations. Weekly monitoring of helminth prevalences and pasture infestation was performed for 1 yr in several extensive maintenance systems of two wildlife parks with similar climates to determine when veterinary intervention to control parasites would be useful. We also sought evidence of natural immunogenic reactions among herds of Chapman zebras (Equus quagga antiquorum), Przewalski's horses (Equus przewalskii) and dwarf donkeys (Equus asinus africanus). Fecal and vegetation samples and cultures for third-stage larvae revealed permanent egg shedding in the three species and pasture infestation during the warm, moist periods (July-September) in all enclosures. Stable social structure and low equid population density may be sufficient to make prophylaxis unnecessary in adults, whereas biotic and abiotic environmental factors such as crowding, animal transfers, social integration of subadults, and weaning stress may facilitate temporary severe infections of individuals. Biweekly helminth monitoring is a useful diagnostic tool for extensive management of exotic equids.

Fishery of the Green Jack Caranx caballus (Osteichytes: Carangidae in Las Perlas Archipelago, Pacific Panama

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James M. Mair

2012-09-01

Full Text Available Green Jacks, Caranx caballus, are distributed along the Eastern Pacific coast. In Panama, C. caballus was heavily fished around Las Perlas Archipelago to sustain local markets until 2007, when the archipelago was declared a marine protected area. This first study in Panama, analyzed a sample of 4 990 individuals from Las Perlas, obtained monthly from June 2005 to June 2006, from landings at the central fish market. Average total length was 36.1±6.4cm and optimum length 38.9cm. Approximately 68% of fish lengths were within ±10% of the optimal length but only six (15% were considered mega-spawners. The von Bertalanffy parameters describe a long-lived and fast growing species, while mortality rates revealed that C. caballus is under high fishing pressure. Standard length at which half of the population is mature was 38.8cm, and the size at which individuals matured massively, 33cm. Only 10-13% of the fish were immature. C. caballus reproduces two to three times per year, with peaks in December, April, and probably September, and recruits to the population at least twice per year. Catch per unit effort (CPUE was best predicted by minimum annual values of the Multivariate ENSO/ LNSO Index (MEI (R²=0.54. Results show that C. caballus in Pacific Panama is overfished. We recommend the raising of the minimum capture/landing size of this species in order to increase the proportion of megaspawners in the population and guarantee the sustainability of this resource.

Ultrastructure of Sarcocystis bertrami sarcocysts from naturally infected donkey (Equus asinus) from Egypt

Science.gov (United States)

There is considerable confusion concerning Sarcocystis species in equids. Little is known of Sarcocystis infections in donkeys (Equus asinus). Here we describe the structure of Sarcocystis bertrami-like from the donkey by light and transmission electron microscopy (LM, TEM). Nineteen sarcocysts fro...

Effects of feral free-roaming horses on semi-arid rangeland ecosystems: an example from the sagebrush steppe

Science.gov (United States)

Feral horses (Equus caballus) are viewed as a symbol of freedom and power; however, they are also a largely unmanaged, non-native grazer in North America, South America, and Australia. Information on their influence on vegetation and soil characteristics in semi-arid rangelands has been limited by ...

Mitochondrial DNA genetic variations among four horse populations in Egypt

Directory of Open Access Journals (Sweden)

Othman E. Othman

2017-12-01

It is concluded that sequence analysis of mtDNA control region is still the most informative tool for the identification of genetic biodiversity and phylogeny of different horse breeds and populations. The horse populations reared in Egypt possess low genetic diversity and all of them are belonged to Equus caballus breed.

Origin and differentiation of a special fragment from Capra hircus ...

African Journals Online (AJOL)

Administrator

2011-09-07

Sep 7, 2011 ... regions of the special fragment in the GenBank of NCBI. A total number of 80 fragments with identity ... recombined during the long period of evolution within and among species, and might be related to ..... and their association to coat color phenotypes in horses (Equus caballus). Mammalian Genome, 12: ...

Standing sedation in captive zebra (Equus grevyi and Equus burchellii).

Science.gov (United States)

Hoyer, Mark; de Jong, Sara; Verstappen, Frank; Wolters, Marno

2012-03-01

Nine Grevy's zebras (Equus grevyi) and three Burchell's zebras (Equus burchellii) were immobilized in a standing position a total of 70 times for minor, nonpainful procedures over a 9-yr period. Standing sedation was successfully obtained with a combination of detomidine and butorphanol on 47 occasions (67.1%). Detomidine i.m. (median 0.10 mg/kg; range: 0.07-0.21) was administered by dart, followed 10 min later by butorphanol i.m. (median 0.13 mg/kg; range 0.04-0.24). The dosages were varied depending on the initial demeanor of the animal. On 23 occasions (32.9%), small amounts of etorphine (median 2.5 microg/kg; range 1.1-12.3 microg/kg) plus acepromazine (median 10 microg/kg; range 4.4-50 microg/kg) (as in Large Animal-Immobilon) had to be administered i.m. to gain sufficient sedation. In these latter cases, the animals were either excited or known for their aggressive character. The zebras were sufficiently immobilized for the length of most procedures (<45 min) without supplementation. At the end of the procedure, the animals were given atipamezole (2 mg per 1 mg detomidine used) and naltrexone (0.1 mg/kg) to reverse the sedative effects, irrespective of whether etorphine was used or not. Standing sedation, using the combination of the alpha-2 agonist detomidine and the partial agonist-antagonist opioid butorphanol (in some cases supplemented with etorphine + acepromazine), proved to be a very efficacious and safe method to be used in zebras under zoo conditions for short-lasting, nonpainful procedures.

Status of Groundwater Levels and Storage Volume in the Equus Beds Aquifer Near Wichita, Kansas, January 2009

Science.gov (United States)

Hansen, Cristi V.

2009-01-01

Beginning in the 1940s, the Wichita well field was developed in the Equus Beds aquifer in southwestern Harvey County and northwestern Sedgwick County to supply water to the city of Wichita (Williams and Lohman, 1949). In addition to supplying drinking water to the largest city in Kansas, the other primary use of water from the Equus Beds aquifer is to irrigate crops in this agriculture-dominated part of south-central Kansas (Rich Eubank, Kansas Department of Agriculture, Division of Water Resources, oral commun., 2008). The decline of water levels in the aquifer were noted soon after the development of the Wichita well field began (Williams and Lohman, 1949). As water levels in the aquifer decline, the volume of water stored in the aquifer decreases and less water is available to supply future needs. For many years the U.S. Geological Survey (USGS), in cooperation with the city of Wichita, has monitored these changes in water levels and the resulting changes in storage volume in the Equus Beds aquifer as part of Wichita's effort to effectively manage this resource. In 2007, the city of Wichita began using Phase I of the Equus Beds Aquifer Storage and Recovery (ASR) project for large-scale artificial recharge of the Equus Beds aquifer. The ASR project uses water from the Little Arkansas River - either pumped from the river directly or from wells in the riverbank that obtain their water from the river by induced infiltration - as the source of artificial recharge to the Equus Beds aquifer (City of Wichita, 2009).

Placentation in the plains zebra (Equus quagga).

Science.gov (United States)

Allen, W R Twink; Stansfield, Fiona; Wilsher, Sandra

2017-10-01

The placenta and fetal gonads of 12 pregnant plains zebra (Equus quagga), estimated to be between 81 and 239 days of gestation, were examined. The diffuse, microcotyledonary zebra placenta appeared, developmentally, to be 3-4 weeks behind its counterpart in horse pregnancy and this, together with the presence of small and long-lived endometrial cups, low levels of zebra chorionic gonadotrophin in maternal serum and few accessory corpora lutea in the maternal ovaries during the first half of gestation, made zebra pregnancy more similar to donkey than horse pregnancy. Zebra fetal gonads enlarged after 80 days of gestation and their interstitial cells stained positively for 3β hydroxysteroid dehydrogenase and 17,20 lyase steroid enzymes while the trophoblast stained for aromatase. This confirmed that zebra fetal gonads, like those of the horse and donkey, can synthesise C19 androgens, which can then be aromatised by the placenta to C18 oestrogens. It is remarkable that such unusual feto-placental mechanisms of production of gonadotrophic and steroid hormones has persisted unchanged within the genus Equus despite the many physical adaptations and the considerable loss of chromosomes that have occurred during the evolution of its member species.

Evolutionary movement of centromeres in horse, donkey, and zebra.

Science.gov (United States)

Carbone, Lucia; Nergadze, Solomon G; Magnani, Elisa; Misceo, Doriana; Francesca Cardone, Maria; Roberto, Roberta; Bertoni, Livia; Attolini, Carmen; Francesca Piras, Maria; de Jong, Pieter; Raudsepp, Terje; Chowdhary, Bhanu P; Guérin, Gérard; Archidiacono, Nicoletta; Rocchi, Mariano; Giulotto, Elena

2006-06-01

Centromere repositioning (CR) is a recently discovered biological phenomenon consisting of the emergence of a new centromere along a chromosome and the inactivation of the old one. After a CR, the primary constriction and the centromeric function are localized in a new position while the order of physical markers on the chromosome remains unchanged. These events profoundly affect chromosomal architecture. Since horses, asses, and zebras, whose evolutionary divergence is relatively recent, show remarkable morphological similarity and capacity to interbreed despite their chromosomes differing considerably, we investigated the role of CR in the karyotype evolution of the genus Equus. Using appropriate panels of BAC clones in FISH experiments, we compared the centromere position and marker order arrangement among orthologous chromosomes of Burchelli's zebra (Equus burchelli), donkey (Equus asinus), and horse (Equus caballus). Surprisingly, at least eight CRs took place during the evolution of this genus. Even more surprisingly, five cases of CR have occurred in the donkey after its divergence from zebra, that is, in a very short evolutionary time (approximately 1 million years). These findings suggest that in some species the CR phenomenon could have played an important role in karyotype shaping, with potential consequences on population dynamics and speciation.

Population viability analysis on domestic horse breeds (Equus caballus)

DEFF Research Database (Denmark)

Thirstrup, Janne Pia; Bach, Lars; Loeschcke, Volker

2009-01-01

simulation package was used for the population viability analysis. First, we investigated the future viability of these breeds based on present demographic and environmental parameters. Second, a sensitivity analysis revealed the most important variables for the viability of these breeds. Third, we examined...... concerning reproduction of the mares had the greatest impact, with the number of mares actively breeding being the most influential on the population forecasts. The results suggest that closing the Knabstrupper studbooks can be done only if increasing the number of mares actively breeding counteracts...... the loss of genetic variation attributable to such a management strategy. It is recommended, based on these results, that the number of Frederiksborg and Knabstrupper mares actively breeding must be increased to approximately 30% in the 2 breeds that are presently using only 13%, while leaving the third...

Low genetic diversity of the endangered Indian wild ass Equus ...

Indian Academy of Sciences (India)

DEVENDRA KHAIRE

(Equus hemionus khur) belongs to an endangered wild species/subspecies of wild ... species of the Asiatic wild asses, E. hemionus and E. kiang, have been described on .... 57.9. Tseng et al. (2010). 5 -TCA CCC ACT AAA TCT CAA ATC C-3.

Animal and plant remains in a tomb in test-pit 1/05, outside the fortified imperial palace Felix Romuliana

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Dimitrijević Vesna

2007-01-01

Full Text Available During the excavations of a tomb located outside the defence walls of the imperial palace, Felix Romuliana, animal and plant remains were collected the analysis of which is the subject of the present study. The faunal remains include the bones and teeth of domestic animals - mule (Equus caballus x Equus asinus, domestic ox (Bos taurus, sheep (Ovis aries, sheep or goat (Ovis/Capra, pig (Sus domesticus and dog (Canis familiaris, a few remains of wild animals - red deer (Cervus elaphus and fox (Vulpes vulpes, and bone of a bird. Until now, no remains of mule have been discovered on sites originating from the classical period at the territory of Serbia. As for plant remains, pieces of carbonized oak wood (Quercus and maple wood (Acer were found, as well as a carbonized seed of a cultivated grapevine (Vitis vinifera vinifera and a tiny fruit of goosegrass (Galium aparine.

Poppea's bath liquor: the secret proteome of she-donkey's milk.

Science.gov (United States)

Cunsolo, Vincenzo; Muccilli, Vera; Fasoli, Elisa; Saletti, Rosaria; Righetti, Pier Giorgio; Foti, Salvatore

2011-09-06

Donkey's milk is today categorized among the best mother's milk substitute for allergic newborns, due to its much reduced or absent allergenicity, coupled to excellent palatability and nutritional value. However, up to the present, only a handful of proteins had been characterized, just about the standard eight to ten major ones known in all types of milk. By exploiting the combinatorial peptide ligand library technology, and treating large volumes (up to 300 mL) of defatted, de-caseinized (whey) milk, we have been able to identify 106 unique gene products, by far the largest description so far of this precious nutrient. Due to poor knowledge of the donkey's genetic asset, only 10% of the proteins could be identified by consulting the data base of Equus asinus; the largest proportion (70%) could be identified by homology with the proteins of Equus caballus. Copyright © 2011 Elsevier B.V. All rights reserved.

Groundwater-level and storage-volume changes in the Equus Beds aquifer near Wichita, Kansas, predevelopment through January 2015

Science.gov (United States)

Whisnant, Joshua A.; Hansen, Cristi V.; Eslick, Patrick J.

2015-10-01

Development of the Wichita well field began in the 1940s in the Equus Beds aquifer to provide the city of Wichita, Kansas, a new water-supply source. After development of the Wichita well field began, groundwater levels began to decline. Extensive development of irrigation wells that began in the 1970s also contributed to substantial groundwater-level declines. Groundwater-level declines likely enhance movement of brine from past oil and gas production near Burrton, Kansas, and natural saline water from the Arkansas River into the Wichita well field. Groundwater levels reached a historical minimum in 1993 because of drought conditions, irrigation, and the city of Wichita’s withdrawals from the aquifer. In 1993, the city of Wichita adopted the Integrated Local Water Supply Program to ensure that Wichita’s water needs would be met through the year 2050 and beyond as part of its efforts to manage the part of the Equus Beds aquifer Wichita uses. A key component of the Integrated Local Water Supply Program was the Equus Beds Aquifer Storage and Recovery project. The Aquifer Storage and Recovery project’s goal is to store and eventually recover groundwater and help protect the Equus Beds aquifer from oil-field brine water near Burrton, Kansas, and saline water from the Arkansas River. Since 1940, the U.S. Geological Survey has monitored groundwater levels and storage-volume changes in the Equus Beds aquifer to provide data to the city of Wichita in order to better manage its water supply.

Investigating determinants of yawning in the domestic ( Equus caballus) and Przewalski ( Equus ferus przewalskii) horses

Science.gov (United States)

Górecka-Bruzda, Aleksandra; Fureix, Carole; Ouvrard, Anne; Bourjade, Marie; Hausberger, Martine

2016-10-01

Yawning is rare in herbivores which therefore may be an interesting group to disentangle the potential function(s) of yawning behaviour. Horses provide the opportunity to compare not only animals living in different conditions but also wild versus domestic species. Here, we tested three hypotheses by observing both domestic and Przewalski horses living in semi-natural conditions: (i) that domestic horses may show an elevated rate of yawning as a result of the domestication process (or as a result of life conditions), (ii) that individuals experiencing a higher level of social stress would yawn more than individuals with lower social stress and (iii) that males would yawn more often than females. The study involved 19 Przewalski horses (PHs) and 16 domestic horses (DHs) of different breeds living in large outdoor enclosures. The results showed that there was no difference between the PH and DH in yawning frequency (YF). PHs exhibited much higher levels of social interactions than DHs. There was a positive correlation between yawning frequency and aggressive behaviours in PHs, especially males, supporting the idea that yawning may be associated with more excitatory/stressful social situations. A correlation was found between yawning frequency and affiliative behaviours in DHs, which supports the potential relationship between yawning and social context. Finally, the entire males, but not castrated males, showed much higher levels of yawning than females in both species. The intensity (rather than the valence) of the interaction may be important in triggering yawning, which could therefore be a displacement activity that helps reduce tension.

Brazilian donkeys (Equus asinus) have a low exposure to Neospora spp.

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Galvão, Cynthia Maria Morais de Queiroz; Rezende-Gondim, Mariana Marrega; Chaves, Ana Carla Rodrigues; Schares, Gereon; Ribas, Jorge Raimundo Lins; Gondim, Luís Fernando Pita

2015-01-01

Donkeys (Equus asinus) are closely related to horses and are known to be infected by several equine pathogens. Neospora caninum and Neospora hughesi are protozoan parasites that infect horses, but they were not confirmed in donkeys up to this date. The aim of this study was to evaluate the exposure of donkeys (Equus asinus) to Neospora spp. using tachyzoites of N. caninum as antigen and employing two common serologic methods, IFAT and immunoblot. Sera from 500 donkeys were obtained from 30 municipalities in Bahia state and tested by IFAT. Two of 500 sera were positive for Neospora spp. by IFAT with antibody titers of 100, and recognized a 37kDa antigen in immunoblot. Approximately 22% of the samples showed strong apical reactions and/or incomplete fluorescence, what may cause confusion in the interpretation of IFAT. We concluded that Neospora spp. are possibly of minor importance for Brazilian donkeys. Future studies are necessary to prove that Neospora spp. can naturally infect donkeys.

Brazilian donkeys (Equus asinus have a low exposure to Neospora spp.

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Cynthia Maria Morais de Queiroz Galvão

Full Text Available Donkeys (Equus asinus are closely related to horses and are known to be infected by several equine pathogens. Neospora caninum and Neospora hughesi are protozoan parasites that infect horses, but they were not confirmed in donkeys up to this date. The aim of this study was to evaluate the exposure of donkeys (Equus asinus to Neospora spp. using tachyzoites of N. caninum as antigen and employing two common serologic methods, IFAT and immunoblot. Sera from 500 donkeys were obtained from 30 municipalities in Bahia state and tested by IFAT. Two of 500 sera were positive for Neospora spp. by IFAT with antibody titers of 100, and recognized a 37kDa antigen in immunoblot. Approximately 22% of the samples showed strong apical reactions and/or incomplete fluorescence, what may cause confusion in the interpretation of IFAT. We concluded that Neospora spp. are possibly of minor importance for Brazilian donkeys. Future studies are necessary to prove that Neospora spp. can naturally infect donkeys.

Zygomycetes from herbivore dung in the ecological reserve of Dois Irmãos, Northeast Brazil

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André Luiz Cabral Monteiro de Azevedo Santiago

2011-03-01

Full Text Available Thirty-eight taxa of Zygomycetes distributed in 15 genera were recorded from tapir (Tapirus terrestris, camel (Camelus bactrianus, horse (Equus caballus, deer (Cervus elaphus, agouti (Dasyprocta aguti, donkey (Equus asinus, llama (Llama glama and waterbuck (Kobus ellipsiprymnus dung collected at the Reserva Ecológica de Dois Irmãos located in Recife, State of Pernambuco, Northeast Brazil. The samples were collected on a monthly basis from June 2005 to May 2006, taken to the laboratory and incubated in moist chambers. Higher number of taxa was observed in the excrements of tapir, followed by deer and donkey. The highest number of species was detected for Mucor, followed by Pilobolus. Statistical analyses showed significant differences in richness of Zygomycetes taxa between the herbivore dung types. Differences of species composition, however, were weak. Seasonality influenced the Zygomycetes species composition but not its richness. Variations in taxa composition between ruminants and non-ruminants dung were non significant.

Zygomycetes From Herbivore Dung in the Ecological Reserve of Dois IrmÃOs, Northeast Brazil

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de Azevedo Santiago, André Luiz Cabral Monteiro; Botelho Trufem, Sandra Farto; Malosso, Elaine; dos Santos, Paulo Jorge Parreira; de Queiroz Cavalcanti, Maria Auxiliadora

2011-01-01

Thirty-eight taxa of Zygomycetes distributed in 15 genera were recorded from tapir (Tapirus terrestris), camel (Camelus bactrianus), horse (Equus caballus), deer (Cervus elaphus), agouti (Dasyprocta aguti), donkey (Equus asinus), llama (Llama glama) and waterbuck (Kobus ellipsiprymnus) dung collected at the Reserva Ecológica de Dois Irmãos located in Recife, State of Pernambuco, Northeast Brazil. The samples were collected on a monthly basis from June 2005 to May 2006, taken to the laboratory and incubated in moist chambers. Higher number of taxa was observed in the excrements of tapir, followed by deer and donkey. The highest number of species was detected for Mucor, followed by Pilobolus. Statistical analyses showed significant differences in richness of Zygomycetes taxa between the herbivore dung types. Differences of species composition, however, were weak. Seasonality influenced the Zygomycetes species composition but not its richness. Variations in taxa composition between ruminants and non-ruminants dung were non significant. PMID:24031609

Investigating attentional processes in depressive-like domestic horses (Equus caballus).

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Rochais, C; Henry, S; Fureix, C; Hausberger, M

2016-03-01

Some captive/domestic animals respond to confinement by becoming inactive and unresponsive to external stimuli. Human inactivity is one of the behavioural markers of clinical depression, a mental disorder diagnosed by the co-occurrence of symptoms including deficit in selective attention. Some riding horses display 'withdrawn' states of inactivity and low responsiveness to stimuli that resemble the reduced engagement with their environment of some depressed patients. We hypothesized that 'withdrawn' horses experience a depressive-like state and evaluated their level of attention by confronting them with auditory stimuli. Five novel auditory stimuli were broadcasted to 27 horses, including 12 'withdrawn' horses, for 5 days. The horses' reactions and durations of attention were recorded. Non-withdrawn horses reacted more and their attention lasted longer than that of withdrawn horses on the first day, but their durations of attention decreased over days, but those of withdrawn horses remained stable. These results suggest that the withdrawn horses' selective attention is altered, adding to already evidenced common features between this horses' state and human depression. Copyright © 2016. Published by Elsevier B.V.

Desarrollo de resistencia a la insulina en caballos (Equus caballus)

DEFF Research Database (Denmark)

Gandarillas, Mónica; Matus, José Tomás; Márquez-Hernández, Roberto I.

2015-01-01

In horses, insulin resistance is associated with several comorbidities such as obesity, laminitis, colic and osteochondrosis. The multifactorial causes of insulin resistance in horses have been addressed, which include genetic and environmental factors. As a consequence of these factors, the cell...

Study of early pregnancy factor (EPF) in equine (Equus caballus).

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Ohnuma, K; Yokoo, M; Ito, K; Nambo, Y; Miyake, Y I; Komatsu, M; Takahashi, J

2000-03-01

Early pregnancy factor (EPF) is an immunosuppressive protein detected in the early pregnancy serum. We have already reported that we developed the rosette inhibition test for mare EPF and detected EPF in thoroughbreds. The aim of this study was to determine whether or not our method could be used clinically. The rosette inhibition test for equine EPF was carried out on serum from six nonpregnant and six pregnant Shetland ponies, a female and a male Chinese pony, and four nonpregnant and 13 pregnant thoroughbred mares. In the thoroughbreds sera were collected during the pregnancy period. Furthermore, we measured progesterone and detected pregnant mare serum gonadotrophin (PMSG) in order to confirm pregnancy of the Chinese pony 3 and 6 months after mating. In the nonpregnant Shetland ponies, the rosette inhibition titre (RIT) was 6.0+/-1.0 and EPF was negative. In contrast, in the pregnant ponies, the RIT was 9.2+/-0.4 and EPF was positive. Based on these results, we diagnosed pregnancy of the Chinese pony. The RIT of the female Chinese pony (3 months after mating) was above 10 and EPF was positive. Furthermore, we detected PMSG and progesterone in the serum of this pony. EPF appeared in the maternal blood circulation at 24-72 hr after mating, it was detected until the second trimester, and after that it disappeared from the maternal serum. The pony's EPF was detected by using the same rosette inhibition test as in the thoroughbred and was present from 24 to 72 hr after mating until the second trimester. The results indicated that our method was useful for pregnancy diagnosis of Equine.

A lectin histochemical study to detect variation in glycosylation at the feto-maternal interface in three interbreeding equine species.

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Jones, Carolyn J P; Allen, W R Twink; Wilsher, Sandra

2017-10-01

In this study, we compare glycosylation at the fetomaternal interface in 3 equine species: horse, donkey and zebra, all of which can interbreed to produce hybrids, to assess their glycan similarities and differences. Sections cut from 3 specimens of horse (Equus caballus) placenta (50, 200 and 280 days gestation), one donkey (Equus asinus) placenta (65 cm crown-rump length) and 5 specimens of zebra (Equus quagga) placentae (81-239 days gestation) were stained with a panel of 24 biotinylated lectins using an avidin-peroxidase revealing system. There were only slight quantitative differences in the lectin histochemistry at the feto-maternal interface between all three specimens; zebra placentae expressed more α2,6-linked sialic acid, with α1,2fucosyl residues at the microvillous interface. However, zebra trophoblast showed histological differences from the other two species, with polarised cells, prominent supranuclear Golgi bodies, and fewer intracellular granules. Our findings appear to confirm the hypothesis that closely related, interbreeding species with epitheliochorial placentae express similar glycans at the feto-maternal interface, thereby supporting the existence of a placental glycocode. We also observed intraspecies evolutionary diversion to be associated with a different histological architecture and the absence of significant intracellular granules. Copyright © 2017 Elsevier Ltd. All rights reserved.

LESIONES CUTANEAS PARASITARIAS EN EL ASNO EQUUS ASINUS DE CHORONI, ESTADO ARAGUA, VENEZUELA

DEFF Research Database (Denmark)

Morales, Abelardo; Garcia, Francisco; Rossini, Mario

2010-01-01

Three donkeys (Equus asinus Linnaeus, 1758), two males and a female sex, between 5-8 years of old, in athletic shape, in Choroni, Aragua, Venezuela were examined. Clinical examination evidenced hirsute hair and moderate body condition. Nodular dermatitis like skin lesions showed crusted erythemat...

Mitochondrial genome sequence of the Tibetan wild ass (Equus kiang).

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Luo, Yongjun; Chen, Yu; Liu, Fuyu; Jiang, Chunhua; Gao, Yuqi

2011-02-01

The Tibetan wild ass, or kiang (Equus kiang) is endemic to the cold and hypoxic (4000-7000 m above sea level) climates of the montane and alpine grasslands of the Tibetan Plateau. We report here the complete nucleotide sequence of the E. kiang mitochondrial genome. Our results show that E. kiang mitochondrial DNA is 16,634 bp long, and predicted to encode all the 37 genes that are typical for vertebrates.

Genetic diversity of piroplasms in plains zebra (Equus quagga burchellii) and Cape mountain zebra (Equus zebra zebra) in South Africa.

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Bhoora, Raksha; Buss, Peter; Guthrie, Alan J; Penzhorn, Barend L; Collins, Nicola E

2010-11-24

Seventy EDTA blood samples collected from plains zebra (Equus quagga burchellii) and Cape mountain zebra (Equus zebra zebra) were screened for the presence of piroplasm parasite DNA using quantitative T. equi-specific and B. caballi-specific TaqMan real-time PCR (qPCR) tests. T. equi parasite DNA was detected in 60 samples, 19 of which were also positive for B. caballi. Approximately 1480bp of the piroplasm 18S rRNA gene was amplified and sequenced from 17 samples, while the V4 hypervariable region of the 18S rRNA gene was amplified, cloned and sequenced from 31 samples. BLASTN analysis revealed that all of the sequences obtained were most similar to T. equi genotypes and not B. caballi genotypes. Although Babesia parasites were present in some of these samples, as indicated by qPCR, the parasitaemia may have been too low to allow detection by cloning of PCR products from a mixed infection. Sequence analyses of both the full-length and the V4 hypervariable region of the T. equi 18S rRNA gene revealed the existence of 13 new T. equi sequences from zebra, confirming the existence of sequence heterogeneity in the rRNA genes of the parasites that cause equine piroplasmosis, and further suggesting that there may be additional, as yet unidentified, T. equi and B. caballi 18S rRNA sequences present in the horse and zebra populations in South Africa. The occurrence of previously unrecognized sequence variation could pose a potential problem in the implementation of diagnostic tests targeting the 18S rRNA gene. Copyright © 2010 Elsevier B.V. All rights reserved.

Biometria de pontes de miocárdio em muares (Equus caballus x Equus asinus – Linnaeus 1758

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André Luiz C. Ribeiro

2009-06-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2009v22n3p177 O presente estudo objetivou estudar a freqüência, largura e localização, especialmente no que diz respeito à posição e vasculotopia, das pontes de miocárdio sobre os ramos ventriculares das artérias coronárias direita e esquerda em muares, através da biometria. Estas informações podem contribuir na compreensão das doenças cardíacas, principalmente aquelas relacionadas à circulação coronariana, e na elucidação da importância e funcionalidade das pontes de miocárdio em animais submetidos ou não a esforços físicos. Para isso utilizou-se o muar (n = 30 como modelo, por ser este muitas vezes submetido a extenuantes exercícios físicos de tração. As pontes de miocárdio em muar ocorreram em 76,6% dos corações, o seu número variou de 1 a 7, sendo que foram mais freqüentemente encontradas na porção apical dos corações (37,5% e em igual freqüência sobre os ramos das artérias coronárias direita e esquerda.

CYTOLOGY PULMONARY IN HORSES (EQUUS CABALLUS MAINTAINED THE FIELD OR STABLED

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W. F. Fortes Júnior

2016-11-01

Full Text Available Tracheobronchial secretion was collected by endoscopy (Welch-AllynÒ, 200cm long and 9mm diameter, from equines with different ages, races and sex, for posterior cytological analysis. Thirty-six equines were divided into two groups (Group I = stabled, n = 18; Group II = field regimen, n = 18. Animals of Group I (age = 3.5 years were lodged in the Tarumã´s Jockey Club in Curitiba, Parana State. The equines of Group II always were maintained at field condition (never were stabled, in the farm located in Jacarezinho, Paraná State. Following endoscopic exams, tracheobronchial secretion smears were stained by Pappenhein´s method and submitted to cytological analysis. Group I had higher frequency of tracheal discharge than Group II. The cytological analysis showed more presence of macrophages (58.8%, foamy cells (2.3%, body giant cells (0.2%, neutrophils (4.57%, eosinophils (0.7% and Curshmann´s spirals (0.04% on 3 of the 18 animals. The cytological analysis of Group II showed higher frequency of ciliated epithelial cells than Group I, and no Curshmann´s spirals were observed. In conclusion, data showed that horses stabled had more cytological alterations than the animals maintained at field, therefore more tracheobronchial complications. Thus, the care of place where horse are stabled have influence on development of respiratory diseases, may predispose to affections as Chronic Obstructive Pulmonary Disease and Exercise-Induced Pulmonary Hemorrhage, as well athletic horses may be never reach their full respiratory potential.

Identification of Novel Equine (Equus caballus Tendon Markers Using RNA Sequencing

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Jan M. Kuemmerle

2016-11-01

Full Text Available Although several tendon-selective genes exist, they are also expressed in other musculoskeletal tissues. As cell and tissue engineering is reliant on specific molecular markers to discriminate between cell types, tendon-specific genes need to be identified. In order to accomplish this, we have used RNA sequencing (RNA-seq to compare gene expression between tendon, bone, cartilage and ligament from horses. We identified several tendon-selective gene markers, and established eyes absent homolog 2 (EYA2 and a G-protein regulated inducer of neurite outgrowth 3 (GPRIN3 as specific tendon markers using RT-qPCR. Equine tendon cells cultured as three-dimensional spheroids expressed significantly greater levels of EYA2 than GPRIN3, and stained positively for EYA2 using immunohistochemistry. EYA2 was also found in fibroblast-like cells within the tendon tissue matrix and in cells localized to the vascular endothelium. In summary, we have identified EYA2 and GPRIN3 as specific molecular markers of equine tendon as compared to bone, cartilage and ligament, and provide evidence for the use of EYA2 as an additional marker for tendon cells in vitro.

Esteatosis en un burro (Equus asinus. Primer reporte en Colombia

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José Cardona Á.

2011-12-01

Full Text Available Se describe un caso de esteatosis en un burro (Equus asinus, castrado, de 15 años de edad, procedente del municipio de San Antero (Córdoba, Colombia, al cual se le detectó ligamento nucal engrosado, duro y doloroso, dando la impresión de un doble cuello y edemas subcutáneos indurados en pared costal, abdominal y pectoral. Tambiénpresentó masas duras en la unión de músculos semimembranoso y semitendinoso. Por todo lo anterior, mostró dificultad para realizar movimientos coordinados del cuello, nuca y de traslado. Estos hallazgos obedecen principalmente a una deficiencia de selenio y vitamina E, sirviendo como parámetro diagnóstico para la identificación de esta enfermedad en equinos, por lo cual se determinó la actividad eritrocitica de la enzima glutatión peroxidada (GSH-Px, arrojando resultados muy bajos. Este cuadro es también conocido en equinos como enfermedad de la grasa amarilla o esteatitis, que produce degeneración del tejido adiposo, siendo reemplazado por tejido conectivo con depósitos de calcio. Puede estar asociada a miodegeneración nutricional o distrófica (enfermedad del músculo blanco. Es el primer reporte de esta enfermedad en burros(Equus asinus que se hace en Colombia.

IL26 gene inactivation in Equidae.

Science.gov (United States)

Shakhsi-Niaei, M; Drögemüller, M; Jagannathan, V; Gerber, V; Leeb, T

2013-12-01

Interleukin-26 (IL26) is a member of the IL10 cytokine family. The IL26 gene is located between two other well-known cytokines genes of this family encoding interferon-gamma (IFNG) and IL22 in an evolutionary conserved gene cluster. In contrast to humans and most other mammals, mice lack a functional Il26 gene. We analyzed the genome sequences of other vertebrates for the presence or absence of functional IL26 orthologs and found that the IL26 gene has also become inactivated in several equid species. We detected a one-base pair frameshift deletion in exon 2 of the IL26 gene in the domestic horse (Equus caballus), Przewalski horse (Equus przewalskii) and donkey (Equus asinus). The remnant IL26 gene in the horse is still transcribed and gives rise to at least five alternative transcripts. None of these transcripts share a conserved open reading frame with the human IL26 gene. A comparative analysis across diverse vertebrates revealed that the IL26 gene has also independently been inactivated in a few other mammals, including the African elephant and the European hedgehog. The IL26 gene thus appears to be highly variable, and the conserved open reading frame has been lost several times during mammalian evolution. © 2013 The Authors, Animal Genetics © 2013 Stichting International Foundation for Animal Genetics.

Research on Donkey Populations (Equus Asinus in Banat

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Marcel Matiuti

2011-05-01

Full Text Available Research has been made in what concerns the bodily development of donkeys (Equus asinus in Banat, on a number of 94 specimens. The results have shown a great variety in body measures, colours and hues. The Banat Donkey comes from different areas in Romania, Europe or Levant. In 2010 in Banat there were approx. 1000 donkey specimens, 98% of which pertained to shepherds. In the case of this species the mating occurs naturally, and a selection has never been made. Their meat and milk are only rarely consumed by some communities, even if their milk is highly appreciated in the European Union.

Male harassment influences female movements and associations in Grevy's zebra (Equus grevyi)

OpenAIRE

Siva R. Sundaresan; Ilya R. Fischhoff; DI Rubenstein

2007-01-01

In traditional models for social organization, female movements and association patterns track resource distribution, whereas males track females. More recently, this model has been expanded to include feedback effects of male behavior, especially sexual harassment, on female decisions. In Grevy's zebra (Equus grevyi), males defend territories containing resources attractive to females, who form unstable groups. Past research has explained female behavior based on resource distribution and ne...

Next Generation Semiconductor Based Sequencing of the Donkey (Equus asinus) Genome Provided Comparative Sequence Data against the Horse Genome and a Few Millions of Single Nucleotide Polymorphisms

Science.gov (United States)

Bertolini, Francesca; Scimone, Concetta; Geraci, Claudia; Schiavo, Giuseppina; Utzeri, Valerio Joe; Chiofalo, Vincenzo; Fontanesi, Luca

2015-01-01

Few studies investigated the donkey (Equus asinus) at the whole genome level so far. Here, we sequenced the genome of two male donkeys using a next generation semiconductor based sequencing platform (the Ion Proton sequencer) and compared obtained sequence information with the available donkey draft genome (and its Illumina reads from which it was originated) and with the EquCab2.0 assembly of the horse genome. Moreover, the Ion Torrent Personal Genome Analyzer was used to sequence reduced representation libraries (RRL) obtained from a DNA pool including donkeys of different breeds (Grigio Siciliano, Ragusano and Martina Franca). The number of next generation sequencing reads aligned with the EquCab2.0 horse genome was larger than those aligned with the draft donkey genome. This was due to the larger N50 for contigs and scaffolds of the horse genome. Nucleotide divergence between E. caballus and E. asinus was estimated to be ~ 0.52-0.57%. Regions with low nucleotide divergence were identified in several autosomal chromosomes and in the whole chromosome X. These regions might be evolutionally important in equids. Comparing Y-chromosome regions we identified variants that could be useful to track donkey paternal lineages. Moreover, about 4.8 million of single nucleotide polymorphisms (SNPs) in the donkey genome were identified and annotated combining sequencing data from Ion Proton (whole genome sequencing) and Ion Torrent (RRL) runs with Illumina reads. A higher density of SNPs was present in regions homologous to horse chromosome 12, in which several studies reported a high frequency of copy number variants. The SNPs we identified constitute a first resource useful to describe variability at the population genomic level in E. asinus and to establish monitoring systems for the conservation of donkey genetic resources. PMID:26151450

Next Generation Semiconductor Based Sequencing of the Donkey (Equus asinus Genome Provided Comparative Sequence Data against the Horse Genome and a Few Millions of Single Nucleotide Polymorphisms.

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Francesca Bertolini

Full Text Available Few studies investigated the donkey (Equus asinus at the whole genome level so far. Here, we sequenced the genome of two male donkeys using a next generation semiconductor based sequencing platform (the Ion Proton sequencer and compared obtained sequence information with the available donkey draft genome (and its Illumina reads from which it was originated and with the EquCab2.0 assembly of the horse genome. Moreover, the Ion Torrent Personal Genome Analyzer was used to sequence reduced representation libraries (RRL obtained from a DNA pool including donkeys of different breeds (Grigio Siciliano, Ragusano and Martina Franca. The number of next generation sequencing reads aligned with the EquCab2.0 horse genome was larger than those aligned with the draft donkey genome. This was due to the larger N50 for contigs and scaffolds of the horse genome. Nucleotide divergence between E. caballus and E. asinus was estimated to be ~ 0.52-0.57%. Regions with low nucleotide divergence were identified in several autosomal chromosomes and in the whole chromosome X. These regions might be evolutionally important in equids. Comparing Y-chromosome regions we identified variants that could be useful to track donkey paternal lineages. Moreover, about 4.8 million of single nucleotide polymorphisms (SNPs in the donkey genome were identified and annotated combining sequencing data from Ion Proton (whole genome sequencing and Ion Torrent (RRL runs with Illumina reads. A higher density of SNPs was present in regions homologous to horse chromosome 12, in which several studies reported a high frequency of copy number variants. The SNPs we identified constitute a first resource useful to describe variability at the population genomic level in E. asinus and to establish monitoring systems for the conservation of donkey genetic resources.

Seroprevalence of West Nile Virus in feral horses on Sheldon National Wildlife Refuge, Nevada, United States

Science.gov (United States)

Franson, J. Christian; Hofmeister, Erik K.; Collins, Gail H.; Dusek, Robert J.

2011-01-01

We screened 1,397 feral horses (Equus caballus) on Sheldon National Wildlife Refuge, Nevada, United States, for IgM and IgG against flavivirus during 2004–2006, 2008, and 2009. Positive serum samples were tested for neutralizing antibodies to West Nile virus (WNV) and St. Louis encephalitis virus (SLEV). One animal was positive for antibody against WNV in 2004, but all others tested in 2004–2006 were negative. In 2008 and 2009, we found evidence of increasing seropositive horses with age, whereas seroprevalence of WNV decreased from 19% in 2008 to 7.2% in 2009. No horses were positive for antibody against SLEV. Being unvaccinated, feral horses can be useful for WNV surveillance.

Faune magdalénienne de la Grande Grotte de Labastide. (Hautes - Pyrénées, France.

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André Clot

1988-01-01

Full Text Available La cueva de Labastide (Altos Pirineos, francia ha proporcionado una fauna del Magdaleniense medio (datada en 14.260 ± 440 BP, con especies de gran tamaño, el caballo (Equus caballus cf. gallicus, el bisonte y el uro, el reno. Algunos restos señalan la presencia de la cabra de los Pirineos y del sarrio, sin embargo el ciervo está ausente. Entre los carnívoros, se deben anotar numerosos huesos de zorro   común, y algunos de restos de zorro polar, de línce nórdico y de gato montés. Unos treinta restos pertenecen al glotón, pocas veces citado en los Pirineos.

Karyotypic relationships among Equus grevyi, Equus burchelli and domestic horse defined using horse chromosome arm-specific probes.

Science.gov (United States)

Musilova, P; Kubickova, S; Zrnova, E; Horin, P; Vahala, J; Rubes, J

2007-01-01

Using laser microdissection we prepared a set of horse chromosome arm-specific probes. Most of the probes were generated from horse chromosomes, some of them were derived from Equus zebra hartmannae. The set of probes were hybridized onto E. grevyi chromosomes in order to establish a genome-wide chromosomal correspondence between this zebra and horse. The use of arm-specific probes provided us with more information on the mutual arrangement of the genomes than we could obtain by means of whole-chromosome paints generated by flow sorting, even if we used reciprocal painting with probe sets from both species. By comparison of our results and results of comparative mapping in E. burchelli, we also established the chromosomal correspondence between E. grevyi and E. burchelli, providing evidence for a very close karyotypic relationship between these two zebra species. Establishment of the comparative map for E. grevyi contributes to the knowledge of the karyotypic phylogeny in the Equidae family.

Presencia de Hippidion y Equus (Amerhippus (Mammalia, Perissodactyla y su distribución en el Pleistoceno superior de Chile

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Frassinetti, D.

2000-12-01

Full Text Available Fossil remains belonging to Equidae fram Chilean localities are described and taxonomically determined. Equus (Amerhippus and Hippidion species are identified; its geographic distribution in Chile and relations with others South American Equidae are given; a Late Pleistocene age is regarded for them. Stratigraphic and paleoecological considerations are also included.Se describen y sitúan taxonómicamente los restos de équidos de las localidades chilenas. Se identifican distintas especies de Equus (Amerhippus e Hippidion, señalando su distribución geográfica y relaciones con otros équidos sudamericanos, además de referirlos al Pleistoceno superior. Se analiza su situación estratigráfica así como consideraciones de tipo paleoecológico.

Status of groundwater levels and storage volume in the Equus Beds aquifer near Wichita, Kansas, January 2006 to January 2010

Science.gov (United States)

Hansen, Cristi V.; Aucott, Walter R.

2010-01-01

A part of the Equus Beds aquifer in southwestern Harvey County and northwestern Sedgwick County was developed to supply water to residents of Wichita and for irrigation in south-central Kansas. Groundwater pumping for city and agricultural use caused water levels to decline in a large part of the aquifer northwest of Wichita. In 1965, the city of Wichita began using water from Cheney Reservoir in addition to water from the Equus Beds aquifer to meet the city's increasing demand for water. Irrigation pumpage in the area increased substantially during the 1970s and 1980s and contributed to the water-level declines. Water-level declines reached their maximum to date in October 1992.

Unraveling the sequence and structure of the protein osteocalcin from a 42 ka fossil horse

Science.gov (United States)

Ostrom, Peggy H.; Gandhi, Hasand; Strahler, John R.; Walker, Angela K.; Andrews, Philip C.; Leykam, Joseph; Stafford, Thomas W.; Kelly, Robert L.; Walker, Danny N.; Buckley, Mike; Humpula, James

2006-04-01

We report the first complete amino acid sequence and evidence of secondary structure for osteocalcin from a temperate fossil. The osteocalcin derives from a 42 ka equid bone excavated from Juniper Cave, Wyoming. Results were determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-MS) and Edman sequencing with independent confirmation of the sequence in two laboratories. The ancient sequence was compared to that of three modern taxa: horse ( Equus caballus), zebra ( Equus grevyi), and donkey ( Equus asinus). Although there was no difference in sequence among modern taxa, MALDI-MS and Edman sequencing show that residues 48 and 49 of our modern horse are Thr, Ala rather than Pro, Val as previously reported (Carstanjen B., Wattiez, R., Armory, H., Lepage, O.M., Remy, B., 2002. Isolation and characterization of equine osteocalcin. Ann. Med. Vet.146(1), 31-38). MALDI-MS and Edman sequencing data indicate that the osteocalcin sequence of the 42 ka fossil is similar to that of modern horse. Previously inaccessible structural attributes for ancient osteocalcin were observed. Glu 39 rather than Gln 39 is consistent with deamidation, a process known to occur during fossilization and aging. Two post-translational modifications were documented: Hyp 9 and a disulfide bridge. The latter suggests at least partial retention of secondary structure. As has been done for ancient DNA research, we recommend standards for preparation and criteria for authenticating results of ancient protein sequencing.

Environmental impact on faecal glucocorticoid metabolite concentrations in Grevy's Zebra (Equus grevyi)

OpenAIRE

Yarnell, K; Walker, SL

2017-01-01

The non-invasive nature of faecal glucocorticoid metabolite (FGM) assessment means that sample collection is on an opportunistic basis and samples cannot always be collected immediately upon defection during field studies. Faeces that have been exposed to heat and moisturemay not accurately reflect levels of FGM. Our study exposed male (n=3) and female (n=3) Grevy's zebra (Equus grevyi) faeces to six environmental conditions to simulate a range of weather and seasonal patterns (temperate clim...

Behavioral and Transcriptomic Fingerprints of an Enriched Environment in Horses (Equus caballus.

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Léa Lansade

Full Text Available The use of environmental enrichment (EE has grown in popularity over decades, particularly because EE is known to promote cognitive functions and well-being. Nonetheless, little is known about how EE may affect personality and gene expression. To address this question in a domestic animal, 10-month-old horses were maintained in a controlled environment or EE for 12 weeks. The control horses (n = 9 lived in individual stalls on wood shaving bedding. They were turned out to individual paddocks three times a week and were fed three times a day with pellets or hay. EE-treated horses (n = 10 were housed in large individual stalls on straw bedding 7 hours per day and spent the remainder of the time together at pasture. They were fed three times a day with flavored pellets, hay, or fruits and were exposed daily to various objects, odors, and music. The EE modified three dimensions of personality: fearfulness, reactivity to humans, and sensory sensitivity. Some of these changes persisted >3 months after treatment. These changes are suggestive of a more positive perception of the environment and a higher level of curiosity in EE-treated horses, explaining partly why these horses showed better learning performance in a Go/No-Go task. Reduced expression of stress indicators indicated that the EE also improved well-being. Finally, whole-blood transcriptomic analysis showed that in addition to an effect on the cortisol level, the EE induced the expression of genes involved in cell growth and proliferation, while the control treatment activated genes related to apoptosis. Changes in both behavior and gene expression may constitute a psychobiological signature of the effects of enrichment and result in improved well-being. This study illustrates how the environment interacts with genetic information in shaping the individual at both the behavioral and molecular levels.

Behavioral and Transcriptomic Fingerprints of an Enriched Environment in Horses (Equus caballus).

Science.gov (United States)

Lansade, Léa; Valenchon, Mathilde; Foury, Aline; Neveux, Claire; Cole, Steve W; Layé, Sophie; Cardinaud, Bruno; Lévy, Frédéric; Moisan, Marie-Pierre

2014-01-01

The use of environmental enrichment (EE) has grown in popularity over decades, particularly because EE is known to promote cognitive functions and well-being. Nonetheless, little is known about how EE may affect personality and gene expression. To address this question in a domestic animal, 10-month-old horses were maintained in a controlled environment or EE for 12 weeks. The control horses (n = 9) lived in individual stalls on wood shaving bedding. They were turned out to individual paddocks three times a week and were fed three times a day with pellets or hay. EE-treated horses (n = 10) were housed in large individual stalls on straw bedding 7 hours per day and spent the remainder of the time together at pasture. They were fed three times a day with flavored pellets, hay, or fruits and were exposed daily to various objects, odors, and music. The EE modified three dimensions of personality: fearfulness, reactivity to humans, and sensory sensitivity. Some of these changes persisted >3 months after treatment. These changes are suggestive of a more positive perception of the environment and a higher level of curiosity in EE-treated horses, explaining partly why these horses showed better learning performance in a Go/No-Go task. Reduced expression of stress indicators indicated that the EE also improved well-being. Finally, whole-blood transcriptomic analysis showed that in addition to an effect on the cortisol level, the EE induced the expression of genes involved in cell growth and proliferation, while the control treatment activated genes related to apoptosis. Changes in both behavior and gene expression may constitute a psychobiological signature of the effects of enrichment and result in improved well-being. This study illustrates how the environment interacts with genetic information in shaping the individual at both the behavioral and molecular levels.

Presumptive red maple (Acer rubrum) toxicosis in Grevy's zebra (Equus grevyi).

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Weber, M; Miller, R E

1997-03-01

Two female Grevy's zebras (Equus grevyi), one juvenile and one adult, were treated for hemolytic anemia. The juvenile survived, but the adult animal, which also had methemoglobinemia, was euthanized after it failed to recover from anesthesia. Significant pathologic findings in the adult zebra included generalized icterus, hemoglobinuric nephrosis, and paracentral hepatic necrosis. Serum titers for known infectious causes of anemia were negative. Examination of the zebra holding areas revealed two hybrid red maple (Acer sp.) trees. There was no known exposure to other hemolytic agents. This is the first report of probable red maple-induced hemolysis in zebra.

EFFECT OF TWO PROTOCOLS OF CRYOPRESERVATION ON FERTILIZING CAPACITY OF STALLION (Equus caballus SEMEN EFECTO DE DOS PROTOCOLOS DE CRIOPRESERVACIÓN SOBRE LA CAPACIDAD FECUNDANTE DE SEMEN EQUINO (Equus caballus

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Giovanni Restrepo Betancur

2012-06-01

Full Text Available Abstract. Semen cryopreservation is a fundamental process for the development of biotechnologies for assisted reproduction in horses. The use of cryopreservation techniques with changes in concentrations and the nature of the cryoprotectant, as well as, the different types of vials for storage of semen, have become an alternative to improve the protocols used. The objective of this work was to evaluate the effect of two protocols of cryopreservation (freezing and vitrification on the fertilizing capacity of stallion semen. The study was conducted with horses of the Criollo Colombiano breed. For freezing was used a extender supplemented with egg yolk (4% and dimethyl formamide (5%, and 0.5 mL straws as vials, whereas for vitrification, the extender was supplemented with egg yolk (8% and dimethyl formamide (8%, and cryovials were used as carriers. As post thaw parameters were evaluated: progressive motility, vitality, normal morphology and integrity of the plasma membrane through the hypoosmotic swelling test (HOS. For statistical evaluation was fitted a generalized linear model (GLM and means were compared by the Tukey test. Were found average percentages of progressive motility, vitality, normal morphology and HOS of 41.6 ± 11.8 and 37 ± 8.5, 54.3 ± 10.2 and 52.3 ± 7.8, 83.1 ± 5.4 and 83.6 ± 5.8, 41.7 ± 9.8 and 38.9 ± 3.6, for cryopreserved semen by freezing and vitrification, respectively. There were no statistically significant differences (P ≤ 0.05 between treatments for any of the parameters evaluated. The fertilizing capacity of equine semen cryopreserved by vitrification is comparable to that obtained by conventional freezing.Resumen. La criopreservación de semen es un proceso fundamental en el desarrollo de biotecnologías para la reproducción asistida en equinos. El uso de diferentes técnicas de criopreservación con cambios en las concentraciones y la naturaleza de los crioprotectores, así como en los diferentes tipos de soportes para el almacenamiento del semen, se ha constituido en una alternativa para mejorar los protocolos empleados. El objetivo de este trabajo fue evaluar el efecto de dos protocolos de criopreservación (congelación y vitrificación, sobre la capacidad fecundante del semen equino. El estudio se realizó con equinos de la raza Criollo Colombiano. Para la congelación se empleó un diluyente suplementado con de yema de huevo (4% y dimetilformamida (5%, y pajillas de 0,5 mL como soportes; mientras que para la vitrificación, el diluyente fue suplementado con yema de huevo (8% y dimetilformamida (8% y se usaron crioviales como soportes. Post-descongelación, se evaluaron los parámetros: movilidad progresiva, vitalidad, morfología normal e integridad de la membrana plasmática (HOS. Para la evaluación estadística se ajustó un modelo lineal generalizado (GLM y las medias se compararon por la prueba de Tukey. Se encontraron porcentajes promedio de movilidad progresiva, vitalidad, morfología normal y HOS de 41,6±11,8 y 37,0±8,5, 54,3±10,2 y 52,3±7,8, 83,1±5,4 y 83,6±5,8, 41,7±9,8 y 38,9±3,6, para el semen criopreservado por congelación y vitrificación, respectivamente. No se encontraron diferencias estadísticamente significativas (P ≤ 0,05 entre los tratamientos para ninguno de los parámetros evaluados. La capacidad fecundante del semen equino criopreservado por vitrificación es equiparable a la obtenida por congelación convencional.

Water quality of the Little Arkansas River and Equus Beds Aquifer before and concurrent with large-scale artificial recharge, south-central Kansas, 1995-2012

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Tappa, Daniel J.; Lanning-Rush, Jennifer L.; Klager, Brian J.; Hansen, Cristi V.; Ziegler, Andrew C.

2015-01-01

The city of Wichita artificially recharged about 1 billion gallons of water into the Equus Beds aquifer during 2007–2012 as part of Phase I recharge of the Artificial Storage and Recovery project. This report, prepared in cooperation by the U.S. Geological Survey and the city of Wichita, Kansas, summarizes Little Arkansas River (source-water for artificial recharge) andEquus Beds aquifer water quality before (1995–2006) and during (2007–2012) Artificial Storage and Recovery Phase I recharge. Additionally, aquifer water-quality distribution maps are presented and water-quality changes associated with Phase I recharge timing are described.

A SEROLOGIC AND POLYMERASE CHAIN REACTION SURVEY OF EQUINE HERPESVIRUS IN BURCHELL'S ZEBRAS (EQUUS QUAGGA), HARTMANN'S MOUNTAIN ZEBRAS (EQUUS ZEBRA HARTMANNAE), AND THOMSON'S GAZELLES (EUDORCAS THOMSONII) IN A MIXED SPECIES SAVANNAH EXHIBIT.

Science.gov (United States)

Lopez, Karen M; Fleming, Gregory J; Mylniczenko, Natalie D

2016-12-01

Reports of equine herpesvirus (EHV) 1 and EHV-9 causing clinical disease in a wide range of species have been well documented in the literature. It is thought that zebras are the natural hosts of EHV-9 both in the wild and in captive collections. Concerns about potential interspecies transmission of EHV-1 and EHV-9 in a mixed species savannah exhibit prompted serologic and polymerase chain reaction surveys. Eighteen Burchell's zebras ( Equus quagga ), 11 Hartmann's mountain zebras ( Equus zebra hartmannae), and 14 Thomson's gazelles ( Eudorcas thomsonii ) cohabitating the same exhibit were examined for EHV-1 virus neutralization titers, and evidence of virus via EHV 1-5 polymerase chain reactions. None of the animals had previous exposure to vaccination with EHV-1 or EHV-4. All tested zebras had positive EHV-1 titers, ranging from 4 to 384. All zebras and Thomson's gazelles had negative polymerase chain reaction results for all targeted equine herpesviruses. EHV-9-specific assays are not available but EHV-1, EHV-4, and EHV-9 cross-react serologically. Positive serology results indicate a potential latent equine herpesvirus in the zebra population, which prompted initiation of an equine herpesvirus vaccine protocol, changes in pregnant zebra mare management, and equine herpesvirus polymerase chain reaction screening prior to shipment to or from the study site.

Prevalence of Theileria equi and Babesia caballi as well as the identification of associated ticks in sympatric Grevy's zebras (Equus grevyi) and donkeys (Equus africanus asinus) in northern Kenya.

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Hawkins, Elaine; Kock, Richard; McKeever, Declan; Gakuya, Francis; Musyoki, Charles; Chege, Stephen M; Mutinda, Mathew; Kariuki, Edward; Davidson, Zeke; Low, Belinda; Skilton, Robert A; Njahira, Moses N; Wamalwa, Mark; Maina, Elsie

2015-01-01

The role of equine piroplasmosis as a factor in the population decline of the Grevy's zebra is not known. We determined the prevalence of Babesia caballi and Theileria equi in cograzing Grevy's zebras (Equus grevyi) and donkeys (Equus africanus asinus) in northern Kenya and identified the associated tick vectors. Blood samples were taken from 71 donkeys and 16 Grevy's zebras from March to May 2011. A nested PCR reaction using 18s ribosomal (r)RNA primers on 87 blood spots showed 72% (51/71; 95% confidence interval [CI] 60.4-81.0%) of donkeys and 100% (16/16; 95% CI, 77.3-100%) of Grevy's zebras were T. equi positive. No samples were positive for B. caballi. Sequence comparison using the National Center for Biotechnology Information's basic local alignment search tool identified homologous 18s rRNA sequences with a global geographic spread. The T. equi-derived sequences were evaluated using Bayesian approaches with independent Metropolis-coupled Markov chain Monte Carlo runs. The sequences clustered with those found in Sudan, Croatia, Mongolia, and the US, with statistical support greater than 80% for the two main clades. Hyalomma tick species were found on both donkeys and Grevy's zebras, whereas Rhipicephalus pulchellus was found exclusively on Grevy's zebras and Hyalomma marginatum rupfipes on donkeys. The prevalence of T. equi was 100% in Grevy's zebras and 72% in donkeys with common tick vectors identified. Our results suggest that donkeys and Grevy's zebras can be asymptomatic carriers and that piroplasmosis is endemic in the study area.

The symbiotic intestinal ciliates and the evolution of their hosts.

Science.gov (United States)

Moon-van der Staay, Seung Yeo; van der Staay, Georg W M; Michalowski, Tadeusz; Jouany, Jean-Pierre; Pristas, Peter; Javorský, Peter; Kišidayová, Svetlana; Varadyova, Zora; McEwan, Neil R; Newbold, C Jamie; van Alen, Theo; de Graaf, Rob; Schmid, Markus; Huynen, Martijn A; Hackstein, Johannes H P

2014-04-01

The evolution of sophisticated differentiations of the gastro-intestinal tract enabled herbivorous mammals to digest dietary cellulose and hemicellulose with the aid of a complex anaerobic microbiota. Distinctive symbiotic ciliates, which are unique to this habitat, are the largest representatives of this microbial community. Analyses of a total of 484 different 18S rRNA genes show that extremely complex, but related ciliate communities can occur in the rumen of cattle, sheep, goats and red deer (301 sequences). The communities in the hindgut of equids (Equus caballus, Equus quagga), and elephants (Elephas maximus, Loxodonta africanus; 162 sequences), which are clearly distinct from the ruminant ciliate biota, exhibit a much higher diversity than anticipated on the basis of their morphology. All these ciliates from the gastro-intestinal tract constitute a monophyletic group, which consists of two major taxa, i.e. Vestibuliferida and Entodiniomorphida. The ciliates from the evolutionarily older hindgut fermenters exhibit a clustering that is specific for higher taxa of their hosts, as extant species of horse and zebra on the one hand, and Africa and Indian elephant on the other hand, share related ciliates. The evolutionary younger ruminants altogether share the various entodiniomorphs and the vestibuliferids from ruminants. Copyright © 2014 Elsevier GmbH. All rights reserved.

Identification of copy number variants in horses

KAUST Repository

Doan, R.

2012-03-01

Copy number variants (CNVs) represent a substantial source of genetic variation in mammals. However, the occurrence of CNVs in horses and their subsequent impact on phenotypic variation is unknown. We performed a study to identify CNVs in 16 horses representing 15 distinct breeds (Equus caballus) and an individual gray donkey (Equus asinus) using a whole-exome tiling array and the array comparative genomic hybridization methodology. We identified 2368 CNVs ranging in size from 197 bp to 3.5 Mb. Merging identical CNVs from each animal yielded 775 CNV regions (CNVRs), involving 1707 protein- and RNA-coding genes. The number of CNVs per animal ranged from 55 to 347, with median and mean sizes of CNVs of 5.3 kb and 99.4 kb, respectively. Approximately 6% of the genes investigated were affected by a CNV. Biological process enrichment analysis indicated CNVs primarily affected genes involved in sensory perception, signal transduction, and metabolism. CNVs also were identified in genes regulating blood group antigens, coat color, fecundity, lactation, keratin formation, neuronal homeostasis, and height in other species. Collectively, these data are the first report of copy number variation in horses and suggest that CNVs are common in the horse genome and may modulate biological processes underlying different traits observed among horses and horse breeds.

Initial study of wild horse and burro demography: determination of pregnancy and lactation rates in various herds. Final report

International Nuclear Information System (INIS)

Wolfe, M.L.; Ellis, L.C.

1982-01-01

Blood serum concentrations of reproductive hormones were used to estimate pregnancy rates in 558 wild and free-roaming horses (Equus caballus) from Nevada, Oregon, and Wyoming; and 165 burros from California. Levels of progesterone, pregnant mares' serum gonadotropin (PMSG), and estradiol 17B were determined by radioimmunoassay procedures. Based on comparison with the results of pregnancy diagnosis from rectal palpations (n =124), the following endocrine concentrations were established as criteria sufficient to indicate pregnancy: progesterone, 0.05 ng/ml; and/or PMSG, 3.0 mg/ml; and/or estradiol, 300 pg/ml. Estimated accuracy of pregnancy diagnoses from endocrine criteria was 80 to 85 percent. The mean incidence of pregnancy among mares sampled from Nevada, Oregon, and Wyoming was 58.4 percent, 69.2 percent, and 85.3 percent respectively

The systematic position of Equus hydruntinus, an extinct species of Pleistocene equid⋆

Science.gov (United States)

Burke, Ariane; Eisenmann, Vera; Ambler, Graeme K.

2003-05-01

Palaeolithic people commonly hunted Equus hydruntinus, an extinct species of equid whose cursorial body proportions suggest an adaptation to semi-arid conditions. Despite the frequency with which it is encountered in fossil deposits, only partial cranial remains have been reported until now. As a result, the systematic affiliation of the species remains a subject of controversy. Two nearly complete E. hydruntinus crania are presented here for the first time. These skulls show that E. hydruntinus is a distinct species, more closely related to the hemiones (Asiatic asses) than to any other equid. This suggests that the social organisation of E. hydruntinus followed one of two known equid sociotypes: resource defense territoriality.

Inoculação experimental de Equus asinus com Leishmania chagasi Cunha & Chagas, 1937 Experimental infection of Equus asinus with Leishmania chagasi Cunha & Chagas, 1937

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Elúzio José Lima Cerqueira

2003-12-01

Full Text Available Quatro Equus asinus foram inoculados com promastigotas de Leishmania chagasi Cunha & Chagas, 1937 e acompanhados durante 12 meses através de: pesquisa de amastigotas em esfregaços e culturas de sangue periférico em fragmentos de tecido do lábio inferior, medula óssea, baço e fígado e de testes de ELISA e TRALd. Estes foram positivos nos 8º, 10º e 12º meses após a inoculação. O exame histopatológico pós necropsia, demonstrou discreto número de amastigotas no fígado de dois dos eqüídeos inoculados. Apesar de desafiados com elevado número de promastigotas, os animais não desenvolveram infecções patentes e não infectaram experimentalmente a vetora Lutzomya longipalpis. Os resultados induzem a acreditar que os eqüídeos são desprovidos de importância como reservatórios na cadeia de transmissão da leishmaniose visceral, embora sirvam como boa fonte de alimentação sangüínea e proliferação da vetora Lutzomyia longipalpis.Four Equus asinus were challenged with promastigotes of Leishmania chagasi Cunha & Chagas, 1937, and followed up for 12 months. They were observed by means of direct testing for promastigotes in smears and culture of peripheral blood, fragments from inferior lip, bone marrow, spleen and liver and the immunological assays ELISA and TRALd. The post-necropsy histological examination demonstrated a small number of amastigotes in the liver of two animals. ELISA and TRALd tests were positive at the 8th, 10th and 12th month after inoculation. The results suggest that the donkeys were able to overcome the experimental leishmanial infection and did not infect the vector Lutzomyia longipalpis in the laboratory. Consequently they can not be considered an important reservoir in the epidemiological chain of transmission of visceral leishmaniasis, although they represent an important blood source for the vector and its proliferation.

Cardiac evaluation of anesthetized Grevy's zebras (Equus grevyi).

Science.gov (United States)

Adin, Darcy B; Maisenbacher, Herbert W; Ojeda, Nyurka; Fiorello, Christine V; Estrada, Amara H; Prosek, Robert; Citino, Scott B

2007-02-01

To determine ECG and echocardiographic measurements in healthy anesthetized Grevy's zebras (Equus grevyi). 20 healthy zebras. Auscultation, base-apex ECG, and echocardiography were performed on anesthetized zebras. Low-grade systolic murmurs were detected in the left basilar region in 4 of 20 zebras. Evaluation of ECGs from 19 zebras revealed sinus rhythm with a predominantly negative QRS complex and a mean +/- SD heart rate of 67 +/- 10 beats/min. Echocardiograms of sufficient image quality were obtained for 16 zebras. Interventricular septal thickness in diastole, left ventricular chamber in diastole and systole, left atrial diameter, and left ventricular mass were significantly and moderately correlated with estimated body weight (r values ranged from 0.650 to 0.884). Detectable swirling of blood in the right and sometimes the left ventricles was detected in 9 of 16 zebras, whereas physiologic regurgitation of blood was detected for the aortic valve in 3 zebras, pulmonary valve in 2 zebras, mitral valve in 2 zebras, and tricuspid valve in 1 zebra. Results of this study provide reference information for use in the cardiac evaluation of anesthetized Grevy's zebras.

Halicephalobus gingivalis (Nematoda) infection in a Grevy's zebra (Equus grevyi).

Science.gov (United States)

Isaza, R; Schiller, C A; Stover, J; Smith, P J; Greiner, E C

2000-03-01

A 6-yr-old female Grevy's zebra (Equus grevyi) with a disseminated rhabditiform nematode infection is described. Antemortem clinical signs were limited to blindness and abnormal behavior believed to be caused by a recurrent nematode-induced uveitis. Histologic examination of the kidneys, heart, eyes, uterus, and lymph nodes revealed granulomas containing multiple sections of rhabditiform nematodes. Most of the recovered nematodes were larval stages with only a few adult females noted. The adults measured 243-297 microm x 11-16 microm (x = 269 x 14 microm). The distinctive rhabditiform esophagi had corpus:isthmus:bulb proportions of 19:11:5. On the basis of adult morphology, the nematode was identified as Halicephalobus gingivalis. This is the first report of this parasite in a zebra and indicates that this parasitic granulomatous disease should be considered in zebras with neurologic disease.

Seroepidemiology of Sarcocystis neurona and Neospora hughesi infections in domestic donkeys (Equus asinus) in Durango, Mexico

OpenAIRE

Alvarado-Esquivel, Cosme; Howe, Daniel K.; Yeargan, Michelle R.; Alvarado-Esquivel, Domingo; Alfredo Zamarripa-Barboza, Jos?; Dubey, Jitender P.

2017-01-01

There is currently no information regarding Sarcocystis neurona and Neospora hughesi infections in donkeys in Mexico. Here, we determined the presence of antibodies against S. neurona and N. hughesi in donkeys in the northern Mexican state of Durango. Serum samples of 239 domestic donkeys (Equus asinus) were assayed for S. neurona and N. hughesi antibodies using home-made enzyme-linked immunoassays; six (2.5%) of the 239 donkeys tested seropositive for S. neurona. The seroprevalence of S. neu...

Influences of immunocontraception on time budgets, social behavior, and body condition in feral horses

Science.gov (United States)

Ransom, J.I.; Cade, B.S.; Hobbs, N.T.

2010-01-01

Managers concerned with shrinking habitats and limited resources for wildlife seek effective tools for limiting population growth in some species. Fertility control is one such tool, yet little is known about its impacts on the behavioral ecology of wild, free-roaming animals. We investigated influences of the immunocontraceptive porcine zona pellucida (PZP) on individual and social behavior in bands of feral horses (Equus caballus) in three discrete populations and used 14 hierarchical mixed effect models to gain insight into the influences of PZP treatment on feral horse behavior. A model of body condition was the strongest predictor of feeding, resting, maintenance, and social behaviors, with treated females allocating their time similarly to control females. Time spent feeding declined 11.4% from low condition to high condition females (F1,154 = 26.427, P modifications in feral horses.

Determining Home Range and Preferred Habitat of Feral Horses on the Nevada National Security Site Using Geographic Information Systems

Energy Technology Data Exchange (ETDEWEB)

Burns, Ashley V. [Univ. of Denver, CO (United States)

2014-05-30

Feral horses (Equus caballus) are free-roaming descendants of domesticated horses and legally protected by the Wild and Free-Roaming Horses and Burros Act of 1971, which mandates how feral horses and burros should be managed and protected on federal lands. Using a geographic information system to determine the home range and suitable habitat of feral horses on the federally managed Nevada National Security Site can enable wildlife biologists in making best management practice recommendations. Home range was estimated at 88.1 square kilometers. Site suitability was calculated for elevation, forage, slope, water presence and horse observations. These variables were combined in successive iterations into one polygon. Suitability rankings established that 85 square kilometers are most suitable habitat, with 2,052 square kilometers of good habitat 1,252 square kilometers of fair habitat and 122 square kilometers of least suitable habitat.

Adaptive evolution of the mitochondrial ND6 gene in the domestic horse.

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Ning, T; Xiao, H; Li, J; Hua, S; Zhang, Y P

2010-01-26

Mitochondria play a crucial role in energy metabolism through oxidative phosphorylation. Organisms living at high altitudes are potentially influenced by oxygen deficits and cold temperatures. The severe environmental conditions can impact on metabolism and direct selection of mitochondrial DNA. As a wide-ranging animal, the domestic horse (Equus caballus) has developed various morphological and physiological characteristics for adapting to different altitudes. Thus, this is a good species for studying adaption to high altitudes at a molecular level. We sequenced the complete NADH dehydrogenase 6 gene (ND6) of 509 horses from 24 sampling locations. By comparative analysis of three horse populations living at different altitudes (>2200 m, 1200-1700 m, and horses was found distributed on the selected branches. We conclude that the high-altitude environment has directed adaptive evolution of the mitochondrial ND6 gene in the plateau horse.

Toxoplasma gondii seroprevalence in donkeys (Equus asinus) from the U.S.A. and isolation of T. gondii from cats on donkey farms

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Donkeys (Equus asinus) are used as companion animals, in leisure activities as working animals, for onotherapy, and their meat and milk is used for human consumption in certain countries. Here we report first serological survey for Toxoplasma gondii in donkeys in the U.S.A. Serum samples were collec...

Prevalence of Toxoplasma gondii antibodies in domestic donkeys (Equus asinus) in Durango, Mexico slaughtered for human consumption

OpenAIRE

Alvarado-Esquivel, Cosme; Alvarado-Esquivel, Domingo; Dubey, Jitender P

2015-01-01

Background Nothing is known about Toxoplasma gondii prevalence in donkeys in Mexico. Meat from donkey is consumed by humans in Mexico and also exported to other countries. We sought to determine the presence of antibodies against T. gondii in 239 domestic donkeys (Equus asinus) for slaughter in Durango, Mexico using the modified agglutination test (MAT). Donkeys were sampled in four premises (trade centers) where donkeys were gather for shipment to abattoirs in other Mexican states. Results A...

Estudio clínico e histopatológico del Sarcoide Fibroblastico en burros (Equus Asinus) en Colombia

OpenAIRE

Cardona Álvarez, José; Vargas Viloria, Marlene; Perdomo Ayola, Sandra

2013-01-01

El objetivo de este trabajo fue estudiar los aspectos clínicos e histopatológicos del sarcoide fibroblástico (SF) en burros (Equus asinus) del departamento de Córdoba, Colombia. Dicho estudio fue de tipo descriptivo, no probabilístico, en animales de conveniencia. Se utilizaron siete burros con SF diagnosticados clínica e histopatológicamente en diferentes explotaciones ganaderas del Departamento. Al describir las lesiones se observó apariencia exofítica fibrovascular, pa...

Breed and species comparison of amino acid transport variation in equine erythrocytes.

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Fincham, D A; Young, J D; Mason, D K; Collins, E A; Snow, D H

1985-05-01

The amino acid permeability of red blood cells from Equus caballus (thoroughbred, Arab, shire and pony), E przewalskii (Przewalski's horse), E asinus (donkey and mule) and E burchelli (common or plains zebra) was measured. Individual animals exhibited stable but widely differing rates of L-[U-14C]alanine uptake in the range 5 to 1554 mumol (litre cells)-1 h-1 (0.2 mM extracellular L-alanine, 37 degrees C). Of the thoroughbreds tested, 30 per cent had red blood cells which were essentially impermeable to L-alanine (5 to 10 mumol (litre cells)-1 h-1, giving transport rates similar to those found previously in amino acid transport-deficient sheep erythrocytes. In contrast, only 3 per cent of the ponies tested had red blood cells impermeable to L-alanine. No cases of erythrocyte amino acid transport deficiency were found in the other horse breeds and species tested.

Lactate turnover in fast-moving vertebrates: The control of plasma metabolite fluxes

Energy Technology Data Exchange (ETDEWEB)

Weber, J.M.

1987-01-01

The goals of this thesis were: (1) to investigate the major factors involved in the regulation of plasma metabolite turnover at the whole-organism level-using lactate as a model, and (2) to determine whether endurance-adapted animals can support higher lactate turnover rates than sedentary animals. Lactate turnover was measured by bolus injection of (U{sup {minus}14}C)lacetate in skipjack tuna, Katsuwonus pelamis, and in thoroughbred race horses, Equus caballus. In tuna, turnover rates ranged from 112 to 431 umol min{sup {minus}1} kg{sup {minus}1}, and they were positively correlated with (lactate). These rates were higher than expected for a mammal of equivalent size. Plots of resting lactate and glucose turnover rates vs body mass on a log-log scale were linear for a wide range mammalian body sizes, and they showed the same slope as the classic body mass vs metabolic rate relationship.

A new record of Equus (Mammalia: Equidae from the Late Pleistocene of central-south Chile Un nuevo registro de Equus (Mammalia: Equidae para el Pleistoceno Superior de Osorno, Chile

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OMAR P RECABARREN

2011-12-01

Full Text Available Fourteen dental and bone parts of a horse excavated from the Pilauco paleontological site, Osorno (40°39' S-73°07' W are analysed and interpreted. This site was formed in association with a peat bog located on the banks of the old Damas River and has conserved abundant late Pleistocene mammalian fauna and flora materials. A date of 11457 ± 140 14C yrs B.P. was obtained from a molar and agrees with our stratigraphic age model. We have identified the fossils as pertaining to the species Equus (Amerhippus andium, which confirms its presence in central-south Chile. Furthermore, the recorded geographic location indicate that the metapodial adaptations of the specimens previously described agree with the reconstructed late Pleistocene landscape of Pilauco, dominated by soft volcanic soils and isolated forest patches over large extensions of grasslands.Se analizan e interpretan 14 fósiles correspondientes a dientes y huesos de caballo registrados en el sitio Pilauco, Osorno (40°39' S-73°07' W. El sitio se formó asociado a un pantano en un borde del antiguo río Damas; en él se ha conservado abundante material de mastofauna y flora pleistocénica. Una fecha radiocarbónica de 11457 ± 140 A.P obtenida de un molar, es concordante con el modelo de edad del sitio. La identificación taxonómica permite asociar a los fósiles a la especie Equus (Amerhippus andium, lo que confirma la presencia de la especie en el centro-sur de Chile. Por otra parte, la posición geográfica de los hallazgos y la reconstrucción del paisaje indicarían que se trata de ejemplares cuyas adaptaciones en los metapodios son concordantes para el paisaje pleistocénico de Pilauco dominado por suelos volcánicos blandos, con presencia de bosquetes dispersos en grandes extensiones de praderas de gramíneas.

Revised shallow and deep water-level and storage-volume changes in the Equus Beds Aquifer near Wichita, Kansas, predevelopment to 1993

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Hansen, Cristi V.; Lanning-Rush, Jennifer L.; Ziegler, Andrew C.

2013-01-01

Beginning in the 1940s, the Wichita well field was developed in the Equus Beds aquifer in southwestern Harvey County and northwestern Sedgwick County to supply water to the city of Wichita. The decline of water levels in the aquifer was noted soon after the development of the Wichita well field began. Development of irrigation wells began in the 1960s. City and agricultural withdrawals led to substantial water-level declines. Water-level declines enhanced movement of brines from past oil and gas activities near Burrton, Kansas and enhanced movement of natural saline water from the Arkansas River into the well field area. Large chloride concentrations may limit use or require the treatment of water from the well field for irrigation or public supply. In 1993, the city of Wichita adopted the Integrated Local Water Supply Program (ILWSP) to ensure an adequate water supply for the city through 2050 and as part of its effort to effectively manage the part of the Equus Beds aquifer it uses. ILWSP uses several strategies to do this including the Equus Beds Aquifer Storage and Recovery (ASR) project. The purpose of the ASR project is to store water in the aquifer for later recovery and to help protect the aquifer from encroachment of a known oilfield brine plume near Burrton and saline water from the Arkansas River. As part of Wichita’s ASR permits, Wichita is prohibited from artificially recharging water into the aquifer in a Basin Storage area (BSA) grid cell if water levels in that cell are above the January 1940 water levels or are less than 10 feet below land surface. The map previously used for this purpose did not provide an accurate representation of the shallow water table. The revised predevelopment water-level altitude map of the shallow part of the aquifer is presented in this report. The city of Wichita’s ASR permits specify that the January 1993 water-level altitudes will be used as a lower baseline for regulating the withdrawal of artificial rechage

Protocols for collection of streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data to describe stream quality for the Hydrobiological Monitoring Program, Equus Beds Aquifer Storage and Recovery Program, city of Wichita, Kansas

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Stone, Mandy L.; Rasmussen, Teresa J.; Bennett, Trudy J.; Poulton, Barry C.; Ziegler, Andrew C.

2012-01-01

The city of Wichita, Kansas uses the Equus Beds aquifer, one of two sources, for municipal water supply. To meet future water needs, plans for artificial recharge of the aquifer have been implemented in several phases. Phase I of the Equus Beds Aquifer Storage and Recovery (ASR) Program began with injection of water from the Little Arkansas River into the aquifer for storage and subsequent recovery in 2006. Construction of a river intake structure and surface-water treatment plant began as implementation of Phase II of the Equus Beds ASR Program in 2010. An important aspect of the ASR Program is the monitoring of water quality and the effects of recharge activities on stream conditions. Physical, chemical, and biological data provide the basis for an integrated assessment of stream quality. This report describes protocols for collecting streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data as part of the city of Wichita's hydrobiological monitoring program (HBMP). Following consistent and reliable methods for data collection and processing is imperative for the long-term success of the monitoring program.

Electrocardiography of Grevy's zebras (Equus grevyi).

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Myers, Debbie A; Citino, Scott; Mitchell, Mark A

2008-09-01

Electrocardiograms (ECGs) are a good baseline test for assessing cardiac rhythm. ECGs have not been reported in any zebra species and in very few Perissodactyla species. Standard limb, six-lead ECGs were recorded in 23 anesthetized Grevy's zebras (Equus grevyi). Heart rate, RR interval, P-wave duration, RR maximum/minimum, PR interval, QRS duration, QT interval, ST segment deviation, P-wave amplitude, QRS amplitude, and T-wave amplitude were measured and calculated from lead II ECGs from these Grevy's zebras. Several variables were tested, including gender, age (0-24, 24-48, 48-180, and >180 mo), weight (350 kg), pregnancy status, and anesthetic differences (standard dose or supplemented dose), to see if they affected ECG values in these animals. There were no significant differences in any of the ECG parameters between genders. RR and QT intervals were longer in older zebras; heart rates were faster in younger zebras. The RR and PR intervals, as well as the QRS duration, were greater in heavier zebras; heart rates were faster in lighter zebras. The RR interval was significantly longer in pregnant zebras. There were no significant differences in any of the ECG parameters for zebras anesthetized with a standardized dose of the drug combination etorphine-detomidine-acepromazine compared to those receiving additional supplements of these drugs and/or ketamine. All other parameters were not significantly different among groups, except where noted previously. The results of this research indicate that differences in ECG parameters in zebras may occur between animals of different ages, weights, and pregnancy status and that these factors should be considered when interpreting the respective ECGs of these zebras.

Non-surgical sterilisation methods may offer a sustainable solution to feral horse (Equus caballus) overpopulation.

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Hall, Sally Elizabeth; Nixon, Brett; Aitken, R John

2017-09-01

Feral horses are a significant pest species in many parts of the world, contributing to land erosion, weed dispersal and the loss of native flora and fauna. There is an urgent need to modify feral horse management strategies to achieve public acceptance and long-term population control. One way to achieve this is by using non-surgical methods of sterilisation, which are suitable in the context of this mobile and long-lived species. In this review we consider the benefits of implementing novel mechanisms designed to elicit a state of permanent sterility (including redox cycling to generate oxidative stress in the gonad, random peptide phage display to target non-renewable germ cells and the generation of autoantibodies against proteins essential for conception via covalent modification) compared with that of traditional immunocontraceptive approaches. The need for a better understanding of mare folliculogenesis and conception factors, including maternal recognition of pregnancy, is also reviewed because they hold considerable potential in providing a non-surgical mechanism for sterilisation. In conclusion, the authors contend that non-surgical measures that are single shot and irreversible may provide a sustainable and effective strategy for feral horse control.

Visual attention, an indicator of human-animal relationships? A study of domestic horses (Equus caballus

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Céline eRochais

2014-02-01

Full Text Available As visual attention is an intrinsic part of social relationships, and because relationships are built on a succession of interactions, their establishment involves learning and attention. The emotional, rewarding or punishing, content can modulate selective attention. In horses, the use of positive/negative reinforcement during training determines short and long-term human-horse relationships. In a recent study in horses, where either food or withers’ grooming were used as a reward, it appeared that only the food-rewarded horses learned the task and show better relationship with humans. In the present study, we hypothesized that this differential effect of grooming/food rewards on learning performances could be due to attentional processes. Monitoring, gazes and behaviors directed towards the trainer revealed that the use of a food reward (FR as positive reinforcement increased horses’ selective attention towards their trainer. Conversely, horses trained with grooming reward (GR expressed more inattentive responses and did not show a decrease of agitated behavior. However, individual plotting of attention versus rate of learning performances revealed a complex pattern. Thus, while all FR horses showed a window of attention related to faster learning performances, GR horses’ pattern followed an almost normal curve where the extreme animals (i.e. highest and lowest attention had the slowest learning performances. On the other hand, learning was influenced by attention: at the end of training, the more attentive horses had also better learning performances. This study, based on horses, contributes to the general debates on the place of attentional processes at the interface of emotion and cognition and open new lines of thought about individual sensitivities (only individuals can tell what an appropriate reward is, attentional processes and learning.

Analysis of Horse Myostatin Gene and Identification of Single Nucleotide Polymorphisms in Breeds of Different Morphological Types

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Stefania Dall'Olio

2010-01-01

Full Text Available Myostatin (MSTN is a negative modulator of muscle mass. We characterized the horse (Equus caballus MSTN gene and identified and analysed single nucleotide polymorphisms (SNPs in breeds of different morphological types. Sequencing of coding, untranslated, intronic, and regulatory regions of MSTN gene in 12 horses from 10 breeds revealed seven SNPs: two in the promoter, four in intron 1, and one in intron 2. The SNPs of the promoter (GQ183900:g.26T>C and GQ183900:g.156T>C, the latter located within a conserved TATA-box like motif were screened in 396 horses from 16 breeds. The g.26C and the g.156C alleles presented higher frequency in heavy (brachymorphic type than in light breeds (dolichomorphic type such as Italian Trotter breed. The significant difference of allele frequencies for the SNPs at the promoter and analysis of molecular variance (AMOVA on haplotypes indicates that these polymorphisms could be associated with variability of morphology traits in horse breeds.

Species identification in meat products: A new screening method based on high resolution melting analysis of cyt b gene.

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Lopez-Oceja, A; Nuñez, C; Baeta, M; Gamarra, D; de Pancorbo, M M

2017-12-15

Meat adulteration by substitution with lower value products and/or mislabeling involves economic, health, quality and socio-religious issues. Therefore, identification and traceability of meat species has become an important subject to detect possible fraudulent practices. In the present study the development of a high resolution melt (HRM) screening method for the identification of eight common meat species is reported. Samples from Bos taurus, Ovis aries, Sus scrofa domestica, Equus caballus, Oryctolagus cuniculus, Gallus gallus domesticus, Meleagris gallopavo and Coturnix coturnix were analyzed through the amplification of a 148 bp fragment from the cyt b gene with a universal primer pair in HRM analyses. Melting profiles from each species, as well as from several DNA mixtures of these species and blind samples, allowed a successful species differentiation. The results demonstrated that the HRM method here proposed is a fast, reliable, and low-cost screening technique. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analysis of Horse Myostatin Gene and Identification of Single Nucleotide Polymorphisms in Breeds of Different Morphological Types

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Dall'Olio, Stefania; Fontanesi, Luca; Nanni Costa, Leonardo; Tassinari, Marco; Minieri, Laura; Falaschini, Adalberto

2010-01-01

Myostatin (MSTN) is a negative modulator of muscle mass. We characterized the horse (Equus caballus) MSTN gene and identified and analysed single nucleotide polymorphisms (SNPs) in breeds of different morphological types. Sequencing of coding, untranslated, intronic, and regulatory regions of MSTN gene in 12 horses from 10 breeds revealed seven SNPs: two in the promoter, four in intron 1, and one in intron 2. The SNPs of the promoter (GQ183900:g.26T>C and GQ183900:g.156T>C, the latter located within a conserved TATA-box like motif) were screened in 396 horses from 16 breeds. The g.26C and the g.156C alleles presented higher frequency in heavy (brachymorphic type) than in light breeds (dolichomorphic type such as Italian Trotter breed). The significant difference of allele frequencies for the SNPs at the promoter and analysis of molecular variance (AMOVA) on haplotypes indicates that these polymorphisms could be associated with variability of morphology traits in horse breeds. PMID:20706663

Cheek tooth morphology and ancient mitochondrial DNA of late Pleistocene horses from the western interior of North America: Implications for the taxonomy of North American Late Pleistocene Equus.

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Christina I Barrón-Ortiz

Full Text Available Horses were a dominant component of North American Pleistocene land mammal communities and their remains are well represented in the fossil record. Despite the abundant material available for study, there is still considerable disagreement over the number of species of Equus that inhabited the different regions of the continent and on their taxonomic nomenclature. In this study, we investigated cheek tooth morphology and ancient mtDNA of late Pleistocene Equus specimens from the Western Interior of North America, with the objective of clarifying the species that lived in this region prior to the end-Pleistocene extinction. Based on the morphological and molecular data analyzed, a caballine (Equus ferus and a non-caballine (E. conversidens species were identified from different localities across most of the Western Interior. A second non-caballine species (E. cedralensis was recognized from southern localities based exclusively on the morphological analyses of the cheek teeth. Notably the separation into caballine and non-caballine species was observed in the Bayesian phylogenetic analysis of ancient mtDNA as well as in the geometric morphometric analyses of the upper and lower premolars. Teeth morphologically identified as E. conversidens that yielded ancient mtDNA fall within the New World stilt-legged clade recognized in previous studies and this is the name we apply to this group. Geographic variation in morphology in the caballine species is indicated by statistically different occlusal enamel patterns in the specimens from Bluefish Caves, Yukon Territory, relative to the specimens from the other geographic regions. Whether this represents ecomorphological variation and/or a certain degree of geographic and genetic isolation of these Arctic populations requires further study.

Identificación de Especímenes de Equus grevyi en el Parque Zoológico Nacional de Cuba

OpenAIRE

Irina Fermin-Morales; Alberto Martín-Mora

2014-01-01

La cebra de Grevy (Equus grevyi) se ha manejado a través de extracciones y reintroducciones de individuos desde su inclusión en la colección de animales del Parque Zoológico Nacional de Cuba. Para mejorar el manejo de esta especie es necesaria la identificación individual a través de caracteres morfológicos, por esto los que los investigadores se propusieron demostrar las diferencias en el patrón de rayado facial existente entre los individuos y entre ambos lados de un mismo individuo. El mét...

Uneven distribution of enamel in the tooth crown of a Plains Zebra (Equus quagga

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Daniela E. Winkler

2015-06-01

Full Text Available Unworn teeth of herbivorous mammals are not immediately functional. They have to be partially worn to expose enamel ridges which can then act as shear-cutting blades to break the food down. We use the Plains Zebra (Equus quagga as a hypsodont, herbivorous model organism to investigate how initial wear of the tooth crown is controlled by underlying structures. We find that the enamel proportion is smaller at the apical half of the tooth crown in all upper tooth positions and suggest that lower enamel content here could promote early wear. Besides this uneven enamel distribution, we note that the third molar has a higher overall enamel content than any other tooth position. The M3 is thus likely to have a slightly different functional trait in mastication, resisting highest bite forces along the tooth row and maintaining functionality when anterior teeth are already worn down.

Uneven distribution of enamel in the tooth crown of a Plains Zebra (Equus quagga).

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Winkler, Daniela E; Kaiser, Thomas M

2015-01-01

Unworn teeth of herbivorous mammals are not immediately functional. They have to be partially worn to expose enamel ridges which can then act as shear-cutting blades to break the food down. We use the Plains Zebra (Equus quagga) as a hypsodont, herbivorous model organism to investigate how initial wear of the tooth crown is controlled by underlying structures. We find that the enamel proportion is smaller at the apical half of the tooth crown in all upper tooth positions and suggest that lower enamel content here could promote early wear. Besides this uneven enamel distribution, we note that the third molar has a higher overall enamel content than any other tooth position. The M3 is thus likely to have a slightly different functional trait in mastication, resisting highest bite forces along the tooth row and maintaining functionality when anterior teeth are already worn down.

Scanning electron microscopy of Strongylus spp. in zebra.

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Els, H J; Malan, F S; Scialdo-Krecek, R C

1983-12-01

The external ultrastructure of the anterior and posterior extremities of the nematodes, Strongylus asini , Strongylus vulgaris, Strongylus equinus and Strongylus edentatus, was studied with scanning electron microscopy (SEM). Fresh specimens of S. asini were collected from the caecum, ventral colon and vena portae of Equus burchelli and Equus zebra hartmannae ; S. vulgaris from the caecum, colon and arteria ileocolica of E. burchelli ; S. equinus from the ventral colon of E. z. hartmannae and S. edentatus from the caecum and ventral colon of both zebras , during surveys of parasites in zebras in the Etosha Game Reserve, South West Africa/Namibia, and the Kruger National Park, Republic of South Africa. The worms were cleaned, fixed and mounted by standard methods and photographed in a JEOL JSM - 35C scanning electron microscope (SEM) operating at 12kV . The SEM showed the following differences: the tips of the external leaf-crowns varied and were fine and delicate in S. asini , coarse and broad in S. vulgaris and, in S. equinus and S. edentatus, closely adherent, separating into single elements for half their length. The excretory pores showed only slight variation, and the morphology of the copulatory bursae did not differ from those seen with light microscopy. The genital cones differed markedly: S. asini had a ventral triangular projection and laterally 2 finger-like projections: in S. vulgaris there were numerous bosses on the lateral and ventral aspects of the cone; in S. equinus 2 finger-like processes projected laterocaudally ; and in S. edentatus 2 pairs of papilla-like processes projected laterally on the ventral aspects, and a pair of rounded projections and a pair of hair-like structures adorned the dorsal aspects.(ABSTRACT TRUNCATED AT 250 WORDS)

[Development and application of real-time PCR for identification and detection of horse meat in animal-origin products].

Science.gov (United States)

Li, Nan; Wang, Jiahui; Shen, Qing; Han, Chunhui; Zhang, Jing; Li, Fengqin; Xu, Jin; Jiang, Tao

2013-11-01

To develop a real-time PCR method for identification and detection of domestic horse meat (Equus caballus) in animal-origin products. The primer and TaqMan-probe was designed and synthesized according to the EU reference laboratory and 87 bp fragments was amplified for horse ingredients. The specificity and sensitivity was tested by artificially spiked horse meat into other domestic meat, such as cattle, sheep, pork, chicken, duck and rabbit. 122 samples of cattle and sheep products were random collected in Beijing market and the detection of horse meat was carried out. The real-time PCR in this study has high specificity and sensitivity for horse meat. No cross-reaction was observed between the horse and sheep, pork, chicken, duck and rabbit meat. There was little cross reaction between horse and cattle when the CT value reach 33. 81. The method can detect 0.1% of horse meat mixed with other domestic animal-origin products. No horse meat ingredients were detected in 122 samples in this survey. There was no horse meat mixed into cattle and sheep products in Beijing marked.

Oxytocin, vasopressin, prostaglandin F(2alpha), luteinizing hormone, testosterone, estrone sulfate, and cortisol plasma concentrations after sexual stimulation in stallions.

Science.gov (United States)

Veronesi, M C; Tosi, U; Villani, M; Govoni, N; Faustini, M; Kindahl, H; Madej, A; Carluccio, A

2010-03-01

This experiment was designed to determine the effects of sexual stimulation on plasma concentrations of oxytocin (OT), vasopressin (VP), 15-ketodihydro-PGF(2alpha) (PG-metabolite), luteinizing hormone (LH), testosterone (T), estrone sulfate (ES), and cortisol (C) in stallions. Semen samples were collected from 14 light horse stallions (Equus caballus) of proven fertility using a Missouri model artificial vagina. Blood samples were collected at 15, 12, 9, 6, and 3 min before estrous mare exposure, at erection, at ejaculation, and at 3, 6, and 9 min after ejaculation. Afterwards, blood sampling was performed every 10 min for the following 60 min. Sexual activity determined an increase in plasma concentrations of OT, VP, C, PG-metabolite, and ES and caused no changes in LH and T concentrations. The finding of a negative correlation between C and VP at erection, and between C and T before erection and at the time of erection, could be explained by a possible inhibitory role exerted by C in the mechanism of sexual arousal described for men. Copyright 2010 Elsevier Inc. All rights reserved.

Serological diagnosis of Besnoitia bennetti infection in donkeys (Equus asinus).

Science.gov (United States)

Ness, SallyAnne L; Schares, Gereon; Peters-Kennedy, Jeanine; Mittel, Linda D; Dubey, Jitender P; Bowman, Dwight D; Mohammed, Hussni O; Divers, Thomas J

2014-11-01

Besnoitiosis is an emerging infectious disease of donkeys (Equus asinus) in the United States for which there are currently no serologic methods of diagnosis. A study was performed to evaluate physical examination findings and 3 serologic assays for the detection of Besnoitia bennetti infection in donkeys. A prospective study of 416 donkeys from 6 privately owned herds across 5 U.S. states (New York, Pennsylvania, Vermont, Oregon, and Washington) was performed. Donkeys were examined for clinical lesions suggestive of besnoitiosis and evaluated for antibodies against B. bennetti using a fluorescent antibody test (FAT) and 2 immunoblot assays specific for bradyzoite and tachyzoite antigens, respectively. Donkeys were confirmed to be infected with B. bennetti by histology (cases; n = 32) and were compared to those with no clinical signs of besnoitiosis (controls; n = 384). Identifying clinical lesions in 2 or more locations correctly identified infected donkeys 83% of the time. Donkeys with besnoitiosis had significantly higher FAT titers (P donkeys. The sensitivity and specificity of the serologic assays for detecting besnoitiosis was 88% and 96% for FAT, 81% and 91% for bradyzoite immunoblot, and 91% and 92% for tachyzoite immunoblot, respectively. Fluorescent antibody and immunoblot assays are effective at identifying donkeys with besnoitiosis and provide a more efficient and less invasive diagnostic alternative to histology. © 2014 The Author(s).

Economic benefit of fertility control in wild horse populations

Science.gov (United States)

Bartholow, J.

2007-01-01

I projected costs for several contraceptive treatments that could be used by the Bureau of Land Management (BLM) to manage 4 wild horse (Equus caballus) populations. Potential management alternatives included existing roundup and selective removal methods combined with contraceptives of different duration and effectiveness. I projected costs for a 20-year economic life using the WinEquus?? wild horse population model and state-by-state cost estimates reflecting BLM's operational expenses. Findings revealed that 1) currently available 2-year contraceptives in most situations are capable of reducing variable operating costs by 15%, 2) experimental 3-year contraceptives may be capable of reducing costs by 18%, and 3) combining contraceptives with modest changes to herd sex ratio (e.g., 55-60% M) could trim costs by 30%. Predicted savings can increase when contraception is applied in conjunction with a removal policy that targets horses aged 0-4 years instead of 0-5 years. However, reductions in herd size result in greater variation in annual operating expenses. Because the horse program's variable operating costs make up about half of the total program costs (which include other fixed costs), contraceptive application and management can only reduce total costs by 14%, saving about $6.1 million per year. None of the contraceptive options I examined eliminated the need for long-term holding facilities over the 20-year period simulated, but the number of horses held may be reduced by about 17% with contraceptive treatment. Cost estimates were most sensitive to the oldest age adoptable and per-day holding costs. The BLM will experience significant cost savings as carefully designed contraceptive programs become widespread in the wild horse herds it manages.

Characterization of a novel variant of amino acid transport system asc in erythrocytes from Przewalski's horse (Equus przewalskii).

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Fincham, D A; Ellory, J C; Young, J D

1992-08-01

In thoroughbred horses, red blood cell amino acid transport activity is Na(+)-independent and controlled by three codominant genetic alleles (h, l, s), coding for high-affinity system asc1 (L-alanine apparent Km for influx at 37 degrees C congruent to 0.35 mM), low-affinity system asc2 (L-alanine Km congruent to 14 mM), and transport deficiency, respectively. The present study investigated amino acid transport mechanisms in red cells from four wild species: Przewalski's horse (Equus przewalskii), Hartmann's zebra (Zebra hartmannae), Grevy's zebra (Zebra grevyi), and onager (Equus hemonius). Red blood cell samples from different Przewalski's horses exhibited uniformly high rates of L-alanine uptake, mediated by a high-affinity asc1-type transport system. Mean apparent Km and Vmax values (+/- SE) for L-alanine influx at 37 degrees C in red cells from 10 individual animals were 0.373 +/- 0.068 mM and 2.27 +/- 0.11 mmol (L cells.h), respectively. As in thoroughbreds, the Przewalski's horse transporter interacted with dibasic as well as neutral amino acids. However, the Przewalski asc1 isoform transported L-lysine with a substantially (6.4-fold) higher apparent affinity than its thoroughbred counterpart (Km for influx 1.4 mM at 37 degrees C) and was also less prone to trans-stimulation effects. The novel high apparent affinity of the Przewalski's horse transporter for L-lysine provides additional key evidence of functional and possible structural similarities between asc and the classical Na(+)-dependent system ASC and between these systems and the Na(+)-independent dibasic amino acid transport system y+. Unlike Przewalski's horse, zebra red cells were polymorphic with respect to L-alanine transport activity, showing high-affinity or low-affinity saturable mechanisms of L-alanine uptake. Onager red cells transported this amino acid with intermediate affinity (apparent Km for influx 3.0 mM at 37 degrees C). Radiation inactivation analysis was used to estimate the target

The presence of Giardia intestinalis in donkeys, Equus asinus, in China.

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Zhang, Xiao-Xuan; Zhang, Fu-Kai; Li, Fa-Cai; Hou, Jun-Ling; Zheng, Wen-Bin; Du, Shuai-Zhi; Zhao, Quan; Zhu, Xing-Quan

2017-01-03

Giardia intestinalis is one of the most important zoonotic enteric parasites. As no information regarding prevalence and genotype of G. intestinalis in donkeys (Equus asinus) in China is available, 181 faecal samples from 48 donkeys from Jilin Province, from 104 from Shandong Province and from 29 from Liaoning Province were examined between May and December 2015. Twenty-eight (15.47%) out of 181 donkey samples were tested G. intestinalis-positive by nested amplification of the triosephosphate isomerase (tpi) gene. The prevalence in different regional groups varied from 10.42 to 18.27%. The prevalence in adult and young donkeys was 14.29 and 22.92%, respectively. Otherwise, the prevalence was 11.69% in summer and 18.27% in winter. However, no statistically significant differences were found in relation to region or age group. Sequence analysis of the tpi, glutamate dehydrogenase (gdh) and beta giardin (bg) loci identified 4, 1 and 3 subtypes of assemblage B, respectively. Moreover, four novel multilocus genotypes (MLGs novel-1 to novel-4) were identified in assemblage B. This first report of G. intestinalis in donkeys in China indicates that further studies of nation-wide molecular epidemiology and geographical distribution of Giardia in donkeys are warranted. Effective strategies should be implemented to control G. intestinalis infection in donkeys, other animals and humans.

Seroepidemiology of Sarcocystis neurona and Neospora hughesi infections in domestic donkeys (Equus asinus in Durango, Mexico

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Alvarado-Esquivel Cosme

2017-01-01

Full Text Available There is currently no information regarding Sarcocystis neurona and Neospora hughesi infections in donkeys in Mexico. Here, we determined the presence of antibodies against S. neurona and N. hughesi in donkeys in the northern Mexican state of Durango. Serum samples of 239 domestic donkeys (Equus asinus were assayed for S. neurona and N. hughesi antibodies using home-made enzyme-linked immunoassays; six (2.5% of the 239 donkeys tested seropositive for S. neurona. The seroprevalence of S. neurona infection was comparable among donkeys regardless of their origin, health status, or sex. Multivariate analysis showed that seropositivity to S. neurona was associated with increased age (OR = 2.95; 95% CI: 1.11–7.82; p = 0.02. Antibodies to N. hughesi were found in two (0.8% of the 239 donkeys. Both exposed donkeys were healthy, 3- and 6-year-old females. This is the first evidence of S. neurona and N. hughesi infections in donkeys in Mexico.

Evaluation of intranasal oxygen supplementation in mules anesthetized with the combination of ketamine, butorphanol, and guaifenesin

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T.J.C. Módolo

Full Text Available ABSTRACT Hypoxemia is a major complication of field anesthesia and no studies regarding this occurrence in mules has been done. Thus, the aim of this study was to evaluate intranasal oxygen supplementation (IOS in mules (Equus caballus x Equus asinus anesthetized with ketamine/butorphanol/guaifenesin combination. For this, we used six male, adult mules (322±29kg which underwent premedication (MPA with 0.2mg/kg of midazolam intramuscularly after 15 minutes, 0.02mg/kg detomidine IV 5 minutes after, induction IV with combination of ketamine (2mg/mL, butorphanol (22.5mg/mL, and guaifenesin (50mg/mL (K/B/G until lateral decumbency. Maintenance was done with the same anesthetic combination. The animals were submitted twice to the protocol described above, 20 days apart, forming two groups. CG: MPA, induction (0.92±0.24mL/kg (mean±SD, and maintenance (2.2±0.2mL/kg/h without SIO; TG: MPA, induction (0.98±0.17mL/kg, and maintenance (2.3±0.4mL/kg/h with IOS flow 40mL/kg/h. During anesthesia arterial blood was collected every 20 minutes (T0, T20, T40, and T60 for blood gas analysis. Data analyzed by ANOVA followed by the Bonferroni test. P<0.05 was considered significant. Hypoxemia of the animals in the CG in periods (59±5; 55±5; 53±7; 49±8 with lower averages than the TG (160±4, 115±34, 92±25, 81±19 was observed, demonstrating that IOS increases PaO2 avoiding the occurrence of hypoxemia.

Horse domestication and conservation genetics of Przewalski's horse inferred from sex chromosomal and autosomal sequences.

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Lau, Allison N; Peng, Lei; Goto, Hiroki; Chemnick, Leona; Ryder, Oliver A; Makova, Kateryna D

2009-01-01

Despite their ability to interbreed and produce fertile offspring, there is continued disagreement about the genetic relationship of the domestic horse (Equus caballus) to its endangered wild relative, Przewalski's horse (Equus przewalskii). Analyses have differed as to whether or not Przewalski's horse is placed phylogenetically as a separate sister group to domestic horses. Because Przewalski's horse and domestic horse are so closely related, genetic data can also be used to infer domestication-specific differences between the two. To investigate the genetic relationship of Przewalski's horse to the domestic horse and to address whether evolution of the domestic horse is driven by males or females, five homologous introns (a total of approximately 3 kb) were sequenced on the X and Y chromosomes in two Przewalski's horses and three breeds of domestic horses: Arabian horse, Mongolian domestic horse, and Dartmoor pony. Five autosomal introns (a total of approximately 6 kb) were sequenced for these horses as well. The sequences of sex chromosomal and autosomal introns were used to determine nucleotide diversity and the forces driving evolution in these species. As a result, X chromosomal and autosomal data do not place Przewalski's horses in a separate clade within phylogenetic trees for horses, suggesting a close relationship between domestic and Przewalski's horses. It was also found that there was a lack of nucleotide diversity on the Y chromosome and higher nucleotide diversity than expected on the X chromosome in domestic horses as compared with the Y chromosome and autosomes. This supports the hypothesis that very few male horses along with numerous female horses founded the various domestic horse breeds. Patterns of nucleotide diversity among different types of chromosomes were distinct for Przewalski's in contrast to domestic horses, supporting unique evolutionary histories of the two species.

Evidence for anthropophily in five species of phlebotomine sand flies (Diptera: Psychodidae) from northern Colombia, revealed by molecular identification of bloodmeals.

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Paternina, Luís E; Verbel-Vergara, Daniel; Romero-Ricardo, Luís; Pérez-Doria, Alveiro; Paternina-Gómez, Margaret; Martínez, Lily; Bejarano, Eduar E

2016-01-01

Identification of the bloodmeal sources of phlebotomine sand flies is fundamental to determining which species are anthropophilic and understanding the transmission of Leishmania parasites in natural epidemiological settings. The objective of this study was to identify sand fly bloodmeals in the mixed leishmaniasis focus of the department of Sucre, northern Colombia. In all 141 engorged female sand flies were analyzed, after being captured in intradomiciliary, peridomiciliary and extradomiciliary habitats with Shannon and CDC traps and by active searching in diurnal resting sites. Bloodmeals were identified by sequencing and analysis of a 358bp fragment of the mitochondrial gene Cytochrome b (CYB) and a 330bp fragment of the nuclear gene prepronociceptin (PNOC). Using both genes 105 vertebrate bloodmeals were identified, with an efficiency of 72% for CYB but only 7% for PNOC. Ten species of vertebrates were identified as providing bloodmeal sources for 8 sand fly species: Homo sapiens (Lutzomyia evansi, Lutzomyia panamensis, Lutzomyia micropyga, Lutzomyia shannoni and Lutzomyia atroclavata), Equus caballus (L. evansi, L. panamensis and Lutzomyia cayennensis cayennensis), Equus asinus (L. evansi and L. panamensis), Bos taurus (L. evansi, L. panamensis and L. c. cayennensis), Tamandua mexicana (L. shannoni and Lutzomyia trinidadensis), Proechimys guyanensis (L. evansi, L. panamensis and L. c. cayennensis), Mabuya sp. (Lutzomyia micropyga), Anolissp. (L. micropyga), Sus scrofa (L. evansi and Lutzomyia gomezi) and Gallus gallus (L. evansi). Cattle, donkeys, humans and pigs were significantly more important than other animals (P=0.0001) as hosts of L. evansi, this being the most abundant sand fly species. The five Lutzomyia species in which blood samples of human origin were detected included L. micropyga and L. atroclavata, constituting the first evidence of anthropophily in both species. Copyright © 2015 Elsevier B.V. All rights reserved.

ANATOMIA ÓSSEA E MUSCULAR DO CÍNGULO ESCAPULAR E BRAÇO DE Tapirus terrestris (PERISSODACTYLA: TAPIRIDAE

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Saulo Gonçalves Pereira

2015-04-01

Full Text Available Tapirus terrestris (Linneaus, 1758 is a mammal found in South America and in almost all Brazilian biomes. The aim of this study was to describe the anatomy of bone and muscle of the scapular cingulum and arm of Tapirus terrestris and compare it with other species of mammals, especially equines. We used four animals donated to the Laboratory of Education and Research of Wild Animals of the Federal University of Uberlândia, after their death with no trauma. The bones were carefully analyzed, described and the muscles were dissected, analyzed and described in accordance with the usual techniques of gross anatomy. The skeleton of the scapular cingulum and arm of Tapirus terrestris is formed by scapula and humerus bones, the lateral muscles of the scapula are subclavian m., deltoid m. supraspinatus m. and infraspinatus, teres minor m., subscapularis m., teres major m., coracobrachialis m., shoulder joint m., biceps brachii m., brachial m. triceps, forearm tensor fasciae m., anconeus m. The muscular and bone standard found is similar to the horse (Equus caballus T. terrestris has bone and muscle characteristics of a suitable animal to displacement and eventual swimming with obvious bone accidents and developed muscles .

Evaluating the impact of domestication and captivity on the horse gut microbiome.

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Metcalf, Jessica L; Song, Se Jin; Morton, James T; Weiss, Sophie; Seguin-Orlando, Andaine; Joly, Frédéric; Feh, Claudia; Taberlet, Pierre; Coissac, Eric; Amir, Amnon; Willerslev, Eske; Knight, Rob; McKenzie, Valerie; Orlando, Ludovic

2017-11-14

The mammal gut microbiome, which includes host microbes and their respective genes, is now recognized as an essential second genome that provides critical functions to the host. In humans, studies have revealed that lifestyle strongly influences the composition and diversity of the gastrointestinal microbiome. We hypothesized that these trends in humans may be paralleled in mammals subjected to anthropogenic forces such as domestication and captivity, in which diets and natural life histories are often greatly modified. We investigated fecal microbiomes of Przewalski's horse (PH; Equus ferus przewalskii), the only horses alive today not successfully domesticated by humans, and herded, domestic horse (E. f. caballus) living in adjacent natural grasslands. We discovered PH fecal microbiomes hosted a distinct and more diverse community of bacteria compared to domestic horses, which is likely partly explained by different plant diets as revealed by trnL maker data. Within the PH population, four individuals were born in captivity in European zoos and hosted a strikingly low diversity of fecal microbiota compared to individuals born in natural reserves in France and Mongolia. These results suggest that anthropogenic forces can dramatically reshape equid gastrointestinal microbiomes, which has broader implications for the conservation management of endangered mammals.

Dimensions of temperament modulate cue-controlled behavior: a study on Pavlovian to instrumental transfer in horses (Equus caballus.

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Léa Lansade

Full Text Available Pavlovian to instrumental transfer (PIT is a central factor in how cues influence animal behavior. PIT refers to the capacity of a Pavlovian cue that predicts a reward to elicit or increase a response intended to obtain the same reward. In the present study, using an equine model, we assessed whether PIT occurs in hoofed domestic animals and whether its efficacy can be modulated by temperamental dimensions. To study PIT, horses were submitted to Pavlovian conditioning whereby an auditory-visual stimulus was repeatedly followed by food delivery. Then, horses were submitted to instrumental conditioning during which they learned to touch with their noses an object signaled by the experimenter in order to obtain the same reward. During the PIT test, the Pavlovian conditioned stimulus was presented to the animal in the absence of reward. At the end of the experiment, a battery of behavioral tests was performed on all animals to assess five temperamental dimensions and investigate their relationships with instrumental performance. The results indicate that PIT can be observed in horses and that its efficacy is greatly modulated by individual temperament. Indeed, individuals with a specific pattern of temperamental dimensions (i.e., higher levels of gregariousness, fearfulness, and sensory sensitivity exhibited the strongest PIT. The demonstration of the existence of PIT in domesticated animals (i.e., horses is important for the optimization of its use by humans and the improvement of training methods. Moreover, because PIT may be implicated in psychological phenomena, including addictive behaviors, the observation of relationships between specific temperamental dimensions and PIT efficacy may aid in identifying predisposing temperamental attributes.

Seroepidemiology of Sarcocystis neurona and Neospora hughesi infections in domestic donkeys (Equus asinus) in Durango, Mexico.

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Alvarado-Esquivel, Cosme; Howe, Daniel K; Yeargan, Michelle R; Alvarado-Esquivel, Domingo; Alfredo Zamarripa-Barboza, José; Dubey, Jitender P

2017-01-01

There is currently no information regarding Sarcocystis neurona and Neospora hughesi infections in donkeys in Mexico. Here, we determined the presence of antibodies against S. neurona and N. hughesi in donkeys in the northern Mexican state of Durango. Serum samples of 239 domestic donkeys (Equus asinus) were assayed for S. neurona and N. hughesi antibodies using home-made enzyme-linked immunoassays; six (2.5%) of the 239 donkeys tested seropositive for S. neurona. The seroprevalence of S. neurona infection was comparable among donkeys regardless of their origin, health status, or sex. Multivariate analysis showed that seropositivity to S. neurona was associated with increased age (OR = 2.95; 95% CI: 1.11-7.82; p = 0.02). Antibodies to N. hughesi were found in two (0.8%) of the 239 donkeys. Both exposed donkeys were healthy, 3- and 6-year-old females. This is the first evidence of S. neurona and N. hughesi infections in donkeys in Mexico. © C. Alvarado-Esquivel et al., published by EDP Sciences, 2017.

Host social rank and parasites: plains zebra (Equus quagga) and intestinal helminths in Uganda.

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Fugazzola, M C; Stancampiano, L

2012-08-13

The main aim of this study was to evaluate the relationship between the social hierarchy of plain zebra, Equus quagga, and the level of parasitism. For the study 141 fecal samples from the same number of animals were collected within the two major populations of E. quagga of Uganda (Lake Mburo Conservation Area and Kidepo Valley National Park). Quantitative (eggs per gram of feces) and qualitative parasite assessment were performed with standard methods. The relationship between parasite burden and individual host features was analyzed using Generalized Linear Models. Strongyles, cestodes, Strongyloides sp. and oxiurids where present in the examined samples. Social rank and age class significantly affect all parasites' abundance with dominant individuals being less parasitized than subordinate individuals, regardless of the parasite groups excluding oxiurids. Sex could not been shown to be related with any of the found parasites. Age was positively related with strongyles and oxiurids abundance and negatively related with cestodes and Strongyloides sp. The main result of the present study was the evidence that social status influences parasite level with dominant zebras shedding less parasite eggs than subordinate ones. Social rank appears, therefore, as an important factor giving rise to parasite aggregation in plain zebras. Copyright © 2012 Elsevier B.V. All rights reserved.

Frequency of Gastric Pathologies in Donkeys (Equus africanus asinus in Córdoba, Colombia

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José Alberto Cardona Álvarez

2015-12-01

Full Text Available This study aimed to determine the frequency of gastric pathologies in donkeys (Equus africanus asinus in the department of Córdoba, Colombia. Stomachs of 137 donkeys (73 intact males, 16 castrated males, and 48 females, aged between 1 to 25 years, were examined, characterized and photographed post mortem. Data on sex, age and pathology were reported on the respective forms and then digitized. Of the total population (137 donkeys, stomach ulcers and associated gastritis were found in 100% of the samples, antral edema in 56.9%, parasites (Trichostrongylus axei in 10.2%, and impaction in 5.8%. Furthermore, Hemomelasma gastric was found in one stomach (0.7%. As a conclusion, 100% of the evaluated animals presented at least some kind of gastric pathology. Acute gastritis was the most frequent type (71.5%, followed in a smaller proportion by chronic gastritis (28.4%. The study showed a significant statistical dependence between age and the degree of injury to the glandular mucosa (p < 0.05. Thus, it evidenced a high incidence of gastric pathologies in donkeys in different livestock holdings in Córdoba, among which squamous ulcers are the most frequent ones, followed by acute gastritis and antral edema. For this reason, it is necessary to do more research and to raise awareness about the treatment of these pathologies in these animals.

Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions.

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Casella, S; Piccione, D; Ielati, S; Bocchino, E G; Piccione, G

2013-06-01

The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome-citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incubated with two different experimental buffer solutions (buffer A: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM glucose; and buffer B: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM MgCl2) in a water bath for 1 h at 25 °C and 37 °C. Normal erythrocytes, suspended at 3% hematocrit, were used to measure the SO4= influx by absorption spectrophotometry at 425 nm wavelength. Unpaired Student's t-test showed a statistically significant decrease (P buffer solutions. Comparing the buffer A with buffer B unpaired Student's t-test showed statistically lower values (P < 0.0001) for A solution versus B solution both at 25 °C and at 37 °C. The greater inhibition of SO4 (=) influx measured in equine erythrocytes indicates the increased formation of the sulfydryl bonds in band 3 and the modulation of the sulfydryl groups, culminating in the conformational changes in band 3. Copyright © 2012 John Wiley & Sons, Ltd.

Parasite-mediated selection drives an immunogenetic tradeoff in plains zebra (Equus quagga)

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Kamath, Pauline L.; Turner, Wendy C.; Küsters, Martina; Getz, Wayne M.

2014-01-01

Pathogen evasion of the host immune system is a key force driving extreme polymorphism in genes of the major histocompatibility complex (MHC). Although this gene family is well characterized in structure and function, there is still much debate surrounding the mechanisms by which MHC diversity is selectively maintained. Many studies have investigated relationships between MHC variation and specific pathogens, and have found mixed support for and against the hypotheses of heterozygote advantage, frequency-dependent or fluctuating selection. Few, however, have focused on the selective effects of multiple parasite types on host immunogenetic patterns. Here, we examined relationships between variation in the equine MHC gene, ELA-DRA, and both gastrointestinal (GI) and ectoparasitism in plains zebras (Equus quagga). Specific alleles present at opposing population frequencies had antagonistic effects, with rare alleles associated with increased GI parasitism and common alleles with increased tick burdens. These results support a frequency-dependent mechanism, but are also consistent with fluctuating selection. Maladaptive GI parasite ‘susceptibility alleles’ were reduced in frequency, suggesting that these parasites may play a greater selective role at this locus. Heterozygote advantage, in terms of allele mutational divergence, also predicted decreased GI parasite burden in genotypes with a common allele. We conclude that an immunogenetic trade-off affects resistance/susceptibility to parasites in this system. Because GI and ectoparasites do not directly interact within hosts, our results uniquely show that antagonistic parasite interactions can be indirectly modulated through the host immune system. This study highlights the importance of investigating the role of multiple parasites in shaping patterns of host immunogenetic variation.

Genetic diversity of the Ethiopian Grevy's zebra (Equus grevyi) populations that includes a unique population of the Alledeghi Plain.

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Kebede, Fanuel; Rosenbom, Sonia; Khalatbari, Leili; Moehlman, Patricia D; Beja-Pereira, Albano; Bekele, Afework

2016-01-01

The endangered Grevy's Zebra (Equus grevyi) is confined to the Horn of Africa, specifically Ethiopia and Kenya. It is threatened by habitat loss and fragmentation due to human encroachment of historic range. Knowledge of population genetics is essential for the development of appropriate conservation actions and management. The focus of this study was to assess the heterogeneity and genetic distinctiveness of the two Grevy's zebra populations in Ethiopia. Non-invasive fecal samples (N = 120) were collected during 2009-2010 from Grevy's zebra populations in the Alledeghi Wildlife Reserve and the Sarite area, Ethiopia. Analyses of a 329 bp of the mtDNA control region of 47 sequences, revealed the existence of two unreported haplotypes in the northern population of Alledeghi, that were not shared with the southern population of Sarite. The Sarite population is contiguous with the Grevy's zebra population in Kenya. The nucleotide diversity levels found in both the populations are extremely low.

High variation and very low differentiation in wide ranging plains zebra (Equus quagga): insights from mtDNA and microsatellites.

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Lorenzen, Eline D; Arctander, Peter; Siegismund, Hans R

2008-06-01

Patterns of genetic differentiation in the plains zebra (Equus quagga) were analysed using mitochondrial DNA control region variation and seven microsatellites. The six morphologically defined subspecies of plains zebra lacked the population genetic structure indicative of distinct evolutionary units. Both marker sets showed high levels of genetic variation and very low levels of differentiation. There was no geographical structuring of mitochondrial DNA haplotypes in the phylogenetic tree, and the plains zebra showed the lowest overall differentiation recorded in any African ungulate studied so far. Arid-adapted African ungulates have shown significant regional genetic structuring in support of the Pleistocene refuge theory. This was not the case in the zebra, and the data are discussed in relation to the impact of Pleistocene climate change on a nonbovid member of the savannah ungulate community. The only other species showing a similar absence of genetic structuring is the African buffalo (Syncerus caffer), but this taxon lacks the high levels of morphological variation present in the plains zebra.

Cryptic etiopathological conditions of equine nervous system with special emphasis on viral diseases

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Rakesh Kumar

2017-12-01

Full Text Available The importance of horse (Equus caballus to equine practitioners and researchers cannot be ignored. An unevenly distributed population of equids harbors numerous diseases, which can affect horses of any age and breed. Among these, the affections of nervous system are potent reason for death and euthanasia in equids. Many episodes associated with the emergence of equine encephalitic conditions have also pose a threat to human population as well, which signifies their pathogenic zoonotic potential. Intensification of most of the arboviruses is associated with sophisticated interaction between vectors and hosts, which supports their transmission. The alphaviruses, bunyaviruses, and flaviviruses are the major implicated groups of viruses involved with equines/humans epizootic/epidemic. In recent years, many outbreaks of deadly zoonotic diseases such as Nipah virus, Hendra virus, and Japanese encephalitis in many parts of the globe addresses their alarming significance. The equine encephalitic viruses differ in their global distribution, transmission and main vector species involved, as discussed in this article. The current review summarizes the status, pathogenesis, pathology, and impact of equine neuro-invasive conditions of viral origin. A greater understanding of these aspects might be able to provide development of advances in neuro-protective strategies in equine population.

The effects of age, rank and neophobia on social learning in horses.

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Krueger, Konstanze; Farmer, Kate; Heinze, Jürgen

2014-05-01

Social learning is said to meet the demands of complex environments in which individuals compete over resources and cooperate to share resources. Horses (Equus caballus) were thought to lack social learning skills because they feed on homogenously distributed resources with few reasons for conflict. However, the horse's social environment is complex, which raises the possibility that its capacity for social transfer of feeding behaviour has been underestimated. We conducted a social learning experiment using 30 socially kept horses of different ages. Five horses, one from each group, were chosen as demonstrators, and the remaining 25 horses were designated observers. Observers from each group were allowed to watch their group demonstrator opening a feeding apparatus. We found that young, low-ranking and more exploratory horses learned by observing older members of their own group, and the older the horse, the more slowly it appeared to learn. Social learning may be an adaptive specialisation to the social environment. Older animals may avoid the potential costs of acquiring complex and potentially disadvantageous feeding behaviours from younger group members. We argue that horses show social learning in the context of their social ecology and that research procedures must take such contexts into account. Misconceptions about the horse's sociality may have hampered earlier studies.

The brain of the horse: weight and cephalization quotients.

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Cozzi, Bruno; Povinelli, Michele; Ballarin, Cristina; Granato, Alberto

2014-01-01

The horse is a common domestic animal whose anatomy has been studied since the XVI century. However, a modern neuroanatomy of this species does not exist and most of the data utilized in textbooks and reviews derive from single specimens or relatively old literature. Here, we report information on the brain of Equus caballus obtained by sampling 131 horses, including brain weight (as a whole and subdivided into its constituents), encephalization quotient (EQ), and cerebellar quotient (CQ), and comparisons with what is known about other relevant species. The mean weight of the fresh brains in our experimental series was 598.63 g (SEM ± 7.65), with a mean body weight of 514.12 kg (SEM ± 15.42). The EQ was 0.78 and the CQ was 0.841. The data we obtained indicate that the horse possesses a large, convoluted brain, with a weight similar to that of other hoofed species of like mass. However, the shape of the brain, the noteworthy folding of the neocortex, and the peculiar longitudinal distribution of the gyri suggest an evolutionary specificity at least partially separate from that of the Cetartiodactyla (even-toed mammals and cetaceans) with whom Perissodactyla (odd-toed mammals) are often grouped.

Analysis of the 227 bp short interspersed nuclear element (SINE insertion of the promoter of the myostatin (MSTN gene in different horse breeds

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Stefania Dall'Olio

2014-09-01

Full Text Available The myostatin (MSTN gene encodes a protein known to be a negative regulator of muscle mass in mammalian species. Different polymorphisms of the horse (Equus caballus MSTN gene have been identified, including single nucleotide polymorphisms and a short interspersed nuclear element (SINE insertion of 227 bp within the promoter of the gene. The SINE insertion has been associated with performance traits in Thoroughbred racehorses and it was proposed as a predictor of optimum racing distance. The aims of this study were to perform in silico analysis to identify putative gains or abrogation of transcription-factor binding sites (TFBSs generated by the SINE allele of the promoter and to analyse the frequency of the SINE insertion in horses used for racing (gallop and trot and other purposes. The SINE insertion was genotyped in 227 horses from 10 breeds belonging to different morphological types (brachimorphic, mesomorphic, meso-dolichomorphic and dolichomorphic. The presence of the insertion was confirmed in the Quarter Horse (SINE allele frequency of 0.81 and in the Thoroughbred (0.51, whereas the SINE allele did not segregate in any of the other analysed breeds. As the SINE MSTN gene polymorphism may be population or breed specific, it is not a useful marker for association studies in all breeds.

Analysis of the 227 bp short interspersed nuclear element (SINE) insertion of the promoter of the myostatin (MSTN) gene in different horse breeds.

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Dall'Olio, Stefania; Scotti, Emilio; Fontanesi, Luca; Tassinari, Marco

2014-01-01

The myostatin (MSTN) gene encodes a protein known to be a negative regulator of muscle mass in mammalian species. Different polymorphisms of the horse (Equus caballus) MSTN gene have been identified, including single nucleotide polymorphisms and a short interspersed nuclear element (SINE) insertion of 227 bp within the promoter of the gene. The SINE insertion has been associated with performance traits in Thoroughbred racehorses and it was proposed as a predictor of optimum racing distance. The aims of this study were to perform in silico analysis to identify putative gains or abrogation of transcription-factor binding sites (TFBSs) generated by the SINE allele of the promoter and to analyse the frequency of the SINE insertion in horses used for racing (gallop and trot) and other purposes. The SINE insertion was genotyped in 227 horses from 10 breeds belonging to different morphological types (brachimorphic, mesomorphic, meso-dolichomorphic and dolichomorphic). The presence of the insertion was confirmed in the Quarter Horse (SINE allele frequency of 0.81) and in the Thoroughbred (0.51), whereas the SINE allele did not segregate in any of the other analysed breeds. As the SINE MSTN gene polymorphism may be population or breed specific, it is not a useful marker for association studies in all breeds.

Peeling back the evolutionary layers of molecular mechanisms responsive to exercise-stress in the skeletal muscle of the racing horse.

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Kim, Hyeongmin; Lee, Taeheon; Park, Woncheoul; Lee, Jin Woo; Kim, Jaemin; Lee, Bo-Young; Ahn, Hyeonju; Moon, Sunjin; Cho, Seoae; Do, Kyoung-Tag; Kim, Heui-Soo; Lee, Hak-Kyo; Lee, Chang-Kyu; Kong, Hong-Sik; Yang, Young-Mok; Park, Jongsun; Kim, Hak-Min; Kim, Byung Chul; Hwang, Seungwoo; Bhak, Jong; Burt, Dave; Park, Kyoung-Do; Cho, Byung-Wook; Kim, Heebal

2013-06-01

The modern horse (Equus caballus) is the product of over 50 million yrs of evolution. The athletic abilities of the horse have been enhanced during the past 6000 yrs under domestication. Therefore, the horse serves as a valuable model to understand the physiology and molecular mechanisms of adaptive responses to exercise. The structure and function of skeletal muscle show remarkable plasticity to the physical and metabolic challenges following exercise. Here, we reveal an evolutionary layer of responsiveness to exercise-stress in the skeletal muscle of the racing horse. We analysed differentially expressed genes and their co-expression networks in a large-scale RNA-sequence dataset comparing expression before and after exercise. By estimating genome-wide dN/dS ratios using six mammalian genomes, and FST and iHS using re-sequencing data derived from 20 horses, we were able to peel back the evolutionary layers of adaptations to exercise-stress in the horse. We found that the oldest and thickest layer (dN/dS) consists of system-wide tissue and organ adaptations. We further find that, during the period of horse domestication, the older layer (FST) is mainly responsible for adaptations to inflammation and energy metabolism, and the most recent layer (iHS) for neurological system process, cell adhesion, and proteolysis.

Morphometric analysis of the neuronal numbers and densities of the inferior olivary complex in the donkey (Equus asinus).

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Alkafafy, Mohamed; Rashed, Reda; Attia, Hossam

2011-07-01

The morphometric interrelations between the compartments of the inferior olivary complex (IOC) in the donkey (Equus asinus) were ascertained by examining serial sections throughout the entire length of the IOC for both sides. Nissl-stained celloidin sections of four brainstems of donkeys were used. The IOC consisted of three major nuclei and four small cell groups. The total neuronal count in both sides of the IOC was 202,040±8480 cells. The medial accessory olivary nucleus (MAO) had the largest relative area (46%) and the highest number of neurons (90,800±7600). The dorsal accessory olivary nucleus (DAO) had the second largest relative area (33%), while the principal olivary nucleus (PO) had the lowest relative area (21%). However, the total neuron count in the PO was larger (60,840±1840) than DAO (50,360±4040). The average neuronal density was 2700±400 cells/mm(3). The numerical values of the current study of the IOC in the donkey were similar to those of other mammals. Copyright © 2010 Elsevier GmbH. All rights reserved.

Human Activity Dampens the Benefits of Group Size on Vigilance in Khulan (Equus hemionus in Western China.

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Mu-Yang Wang

Full Text Available Animals receive anti-predator benefits from social behavior. As part of a group, individuals spend less time being vigilant, and vigilance decreases with increasing group size. This phenomenon, called "the many-eyes effect", together with the "encounter dilution effect", is considered among the most important factors determining individual vigilance behavior. However, in addition to group size, other social and environmental factors also influence the degree of vigilance, including disturbance from human activities. In our study, we examined vigilance behavior of Khulans (Equus hemionus in the Xinjiang Province in western China to test whether and how human disturbance and group size affect vigilance. According to our results, Khulan showed a negative correlation between group size and the percentage time spent vigilant, although this negative correlation depended on the groups' disturbance level. Khulan in the more disturbed area had a dampened benefit from increases in group size, compared to those in the undisturbed core areas. Provision of continuous areas of high-quality habitat for Khulans will allow them to form larger undisturbed aggregations and to gain foraging benefits through reduced individual vigilance, as well as anti-predator benefits through increased probability of predator detection.

Human Activity Dampens the Benefits of Group Size on Vigilance in Khulan (Equus hemionus) in Western China.

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Wang, Mu-Yang; Ruckstuhl, Kathreen E; Xu, Wen-Xuan; Blank, David; Yang, Wei-Kang

2016-01-01

Animals receive anti-predator benefits from social behavior. As part of a group, individuals spend less time being vigilant, and vigilance decreases with increasing group size. This phenomenon, called "the many-eyes effect", together with the "encounter dilution effect", is considered among the most important factors determining individual vigilance behavior. However, in addition to group size, other social and environmental factors also influence the degree of vigilance, including disturbance from human activities. In our study, we examined vigilance behavior of Khulans (Equus hemionus) in the Xinjiang Province in western China to test whether and how human disturbance and group size affect vigilance. According to our results, Khulan showed a negative correlation between group size and the percentage time spent vigilant, although this negative correlation depended on the groups' disturbance level. Khulan in the more disturbed area had a dampened benefit from increases in group size, compared to those in the undisturbed core areas. Provision of continuous areas of high-quality habitat for Khulans will allow them to form larger undisturbed aggregations and to gain foraging benefits through reduced individual vigilance, as well as anti-predator benefits through increased probability of predator detection.

A brief and critical review on hydrofluorosis in diverse species of domestic animals in India.

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Choubisa, Shanti Lal

2018-02-01

India is one of the fluoride-endemic countries where the maximum numbers of ground or drinking water sources are naturally fluoridated. In India, a total of 23, out of 36 states and union territories have drinking water contaminated with fluoride in varying concentration. In the present scenario, especially in rural India, besides the surface waters (perennial ponds, dams, rivers, etc.), bore wells and hand pumps are the principal drinking water sources for domestic animals such as cattle (Bos taurus), water buffaloes (Bubalus bubalis), sheep (Ovis aries), goats (Capra hircus), horses (Equus caballus), donkeys (Equus asinus) and dromedary camels (Camelus dromedarius). Out of 23 states, 17 states, namely Andhra Pradesh, Assam, Bihar, Chhattisgarh, Gujarat, Haryana, Jharkhand, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Odisha (Orissa), Punjab, Rajasthan, Telangana, Uttar Pradesh and West Bengal, have fluoride beyond the maximum permissible limit of 1.0 or 1.5 ppm in drinking water. This situation is a great concern for the animal health because fluoride is a slow toxicant and causes chronic diverse serious health hazards or toxic effects. Despite the fact that domestic animals are the basic income sources in rural areas and possess a significant contributory role not only in the agriculture sector but also in the strengthening of economy as well as in sustainable development of the country, research work on chronic fluoride intoxication (hydrofluorosis) due to drinking of fluoridated water in domestic animals rearing in various fluoride-endemic states is not enough as compared to work done in humans. However, some interesting and excellent research works conducted on different aspects of hydrofluorosis in domesticated animals rearing in different states are briefly and critically reviewed in the present communication. Author believes that this review paper not only will be more useful for researchers to do some more advance research work on fluoride

Twenty years of immunocontraceptive research: lessons learned.

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Miller, Lowell A; Fagerstone, Kathleen A; Eckery, Douglas C

2013-12-01

The National Wildlife Research Center (NWRC) began immunocontraception vaccine research by testing porcine zona pellucida (PZP) on white-tailed deer (Odocoileus virginianus). Early PZP research demonstrated that PZP induced infertility; however, increased length of the rut was observed in PZP-treated deer. An alternative vaccine using a keyhole limpet hemocyanin-gonadotropin-releasing hormone (KLH-GnRH) conjugate formulated with modified Freund's adjuvant was developed at NWRC. Suppression of GnRH has reduced reproduction in both sexes but is most effective in females. This vaccine was effective in preventing contraception in female deer for several years after a prime and boost. Due to adverse side effects of Freund's adjuvant, NWRC developed a new adjuvant called AdjuVac, a mineral oil/surfactant adjuvant with the addition of Mycobacterium avium as an immunostimulant. The price of KLH prompted a search for a more economical hemocyanin carrier protein for the GnRH peptide. Blue protein, derived from the mollusk Concholepas concholepas, proved to be a successful option. Formulation improvements resulted in a vaccine that can be effective as a single injection for multiple years, now called GonaCon. GonaCon is registered with the Environmental Protection Agency (EPA) for use in white-tailed deer in urban/suburban areas and for wild horses (Equus caballus) and burros (Equus asinus). Future GonaCon applications may include reducing reproduction to manage populations of other wildlife species, such as prairie dogs (Cynomys ludovicianus) in urban areas and suppressing reproduction to reduce the spread of venereal diseases such as brucellosis. Research is being conducted to develop a GnRH vaccine used in combination with the rabies vaccine to control population growth in free-roaming dogs, with the secondary effect of managing the spread of rabies. The EPA would regulate all these uses. Research is also ongoing on a GnRH vaccine to delay the onset of adrenocortical

Whole mitochondrial genome sequencing of domestic horses reveals incorporation of extensive wild horse diversity during domestication

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Lippold Sebastian

2011-11-01

Full Text Available Abstract Background DNA target enrichment by micro-array capture combined with high throughput sequencing technologies provides the possibility to obtain large amounts of sequence data (e.g. whole mitochondrial DNA genomes from multiple individuals at relatively low costs. Previously, whole mitochondrial genome data for domestic horses (Equus caballus were limited to only a few specimens and only short parts of the mtDNA genome (especially the hypervariable region were investigated for larger sample sets. Results In this study we investigated whole mitochondrial genomes of 59 domestic horses from 44 breeds and a single Przewalski horse (Equus przewalski using a recently described multiplex micro-array capture approach. We found 473 variable positions within the domestic horses, 292 of which are parsimony-informative, providing a well resolved phylogenetic tree. Our divergence time estimate suggests that the mitochondrial genomes of modern horse breeds shared a common ancestor around 93,000 years ago and no later than 38,000 years ago. A Bayesian skyline plot (BSP reveals a significant population expansion beginning 6,000-8,000 years ago with an ongoing exponential growth until the present, similar to other domestic animal species. Our data further suggest that a large sample of wild horse diversity was incorporated into the domestic population; specifically, at least 46 of the mtDNA lineages observed in domestic horses (73% already existed before the beginning of domestication about 5,000 years ago. Conclusions Our study provides a window into the maternal origins of extant domestic horses and confirms that modern domestic breeds present a wide sample of the mtDNA diversity found in ancestral, now extinct, wild horse populations. The data obtained allow us to detect a population expansion event coinciding with the beginning of domestication and to estimate both the minimum number of female horses incorporated into the domestic gene pool and the

Parasite-mediated selection drives an immunogenetic trade-off in plains zebras (Equus quagga).

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Kamath, Pauline L; Turner, Wendy C; Küsters, Martina; Getz, Wayne M

2014-05-22

Pathogen evasion of the host immune system is a key force driving extreme polymorphism in genes of the major histocompatibility complex (MHC). Although this gene family is well characterized in structure and function, there is still much debate surrounding the mechanisms by which MHC diversity is selectively maintained. Many studies have investigated relationships between MHC variation and specific pathogens, and have found mixed support for and against the hypotheses of heterozygote advantage, frequency-dependent or fluctuating selection. Few, however, have focused on the selective effects of multiple parasite types on host immunogenetic patterns. Here, we examined relationships between variation in the equine MHC gene, ELA-DRA, and both gastrointestinal (GI) and ectoparasitism in plains zebras (Equus quagga). Specific alleles present at opposing population frequencies had antagonistic effects, with rare alleles associated with increased GI parasitism and common alleles with increased tick burdens. These results support a frequency-dependent mechanism, but are also consistent with fluctuating selection. Maladaptive GI parasite 'susceptibility alleles' were reduced in frequency, suggesting that these parasites may play a greater selective role at this locus. Heterozygote advantage, in terms of allele mutational divergence, also predicted decreased GI parasite burden in genotypes with a common allele. We conclude that an immunogenetic trade-off affects resistance/susceptibility to parasites in this system. Because GI and ectoparasites do not directly interact within hosts, our results uniquely show that antagonistic parasite interactions can be indirectly modulated through the host immune system. This study highlights the importance of investigating the role of multiple parasites in shaping patterns of host immunogenetic variation.

Social Class and Group Size as Predictors of Behavior in Male Equus kiang

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Prameek M. Kannan

2017-11-01

Full Text Available Ethograms provide a systematic approach to identify and quantify the repertoire of behaviors of an organism. This information may assist animal welfare in zoos, increase awareness of conservation needs, and help curb high-risk behaviors during human-wildlife conflict. Our primary objective was to utilize an equid ethogram to produce activity budgets for Equus kiang males, a social ungulate that is among the least-studied mammals worldwide, and unknown to the ethological literature. We recently reported the existence of three social classes of this species; Territorial males, Bachelor males and ‘Transient’ males. Therefore, our secondary objective was to compare activity budgets in each of these three groups. We found that kiang spent >70% of their time performing six behaviors: vigilance (34%, locomotion (24.2%, resting (14.2%, mixed foraging (12.5%, browsing (5.1%, and antagonism (1.1%. Over 2% of the total behavioral investment was spent on olfactory investigations (genital sniffing, sniffing proximity and flehmen. Eleven of the eighteen behaviors differed by class. Habitat selection differed strongly by each group, with Territorial males favoring mesic sites with greater vegetation abundance. Vigilance also differed according to habitat selection, but not group size. Animals in the xeric, least vegetation-rich area were far less vigilant than animals at more attractive sites. We found that the full repertoire of behaviors, and relative investments in each, differ according to social class. These findings are a reminder that researchers should make every effort to disambiguate social class among ungulates– and other taxa where behaviors are class-dependent.

Proximate and fatty acid composition of zebra (Equus quagga burchellii) muscle and subcutaneous fat.

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Hoffman, Louwrens C; Geldenhuys, Greta; Cawthorn, Donna-Mareè

2016-08-01

The meat from African game species is healthy, naturally produced and increasingly popular with consumers. Among these species, zebra (Equus quagga burchellii) are growing in number in South Africa, with the meat from surplus animals holding potential to contribute to food security and economic stability. Despite being consumed locally and globally, little information exists on the composition of zebra meat. This study aimed to determine the proximate composition of zebra meat as well as the fatty acid composition of the intramuscular (IMF) and subcutaneous (SCF) fat. Zebra longissimus lumborum muscle was shown to have a high mean protein content (22.29 g per 100 g) and low mean fat content (1.47 g per 100 g). High proportions of polyunsaturated fatty acids (PUFAs) were found in the IMF (41.15%) and SCF (37.71%), mainly comprising α-linolenic (C18:3n-3) and linoleic (C18:2n-6) acids. Furthermore, the IMF and SCF had favourable PUFA/saturated fatty acid ratios (>0.4) and omega-6/omega-3 ratios (<4), indicating that both components are healthy lipid food sources. This study has shed new light on the nutritional value of zebra meat, which will not only be important for food product labelling, nutritional education and incorporation into food composition databases, but will also be indispensable for marketing and export purposes. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Equus: a construção do personagem Alan Strang na tradução cinematográfica.

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Lucyana do Amaral Brilhante

2005-01-01

Full Text Available Peter Shaffer is a British playwright of the second half of the twentieth century. One of his major works is the play Equus, that tells the story of a young man, Alan Strang, who is in psychiatric treatment. The film director Sidney Lumet, with the script of Shaffer, translated the play to the screen. Based on the concept of intersemiotic translation of Jackobson (1995, it may be said that a film adaptation is, in fact, an intersemiotic translation, which in turn is a kind of audiovisual translation. It is then natural that, in the translation of a play to the screen, the original changes because the translations become different texts, normally unattached to the original work. This work’s objective is to analyze the differences between the play and the film. This paper aims at looking at differences between the screenplay and the film, paying special attention to those that affect the character Alan Strang. So, the corpus of the research consists of the film and the play by Schaffer. The analysis of the character was based on translation and literary theories. Keywords: Audiovisual translation, intersemiotic translation, literature and cinema.

Effects of aquifer storage and recovery activities on water quality in the Little Arkansas River and Equus Beds Aquifer, south-central Kansas, 2011–14

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Stone, Mandy L.; Garrett, Jessica D.; Poulton, Barry C.; Ziegler, Andrew C.

2016-07-18

The Equus Beds aquifer in south-central Kansas is aprimary water source for the city of Wichita. The Equus Beds aquifer storage and recovery (ASR) project was developed to help the city of Wichita meet increasing current (2016) and future water demands. The Equus Beds ASR project pumps water out of the Little Arkansas River during above-base flow conditions, treats it using drinking-water quality standards as a guideline, and recharges it into the Equus Beds aquifer for later use. Phase II of the Equus Beds ASR project currently (2016) includes a river intake facility and a surface-water treatment facility with a 30 million gallon per day capacity. Water diverted from the Little Arkansas River is delivered to an adjacent presedimentation basin for solids removal. Subsequently, waste from the surface-water treatment facility and the presedimentation basin is returned to the Little Arkansas River through a residuals return line. The U.S. Geological Survey, in cooperation with the city of Wichita, developed and implemented a hydrobiological monitoring program as part of the ASR project to characterize and quantify the effects of aquifer storage and recovery activities on the Little Arkansas River and Equus Beds aquifer water quality.Data were collected from 2 surface-water sites (one upstream and one downstream from the residuals return line), 1 residuals return line site, and 2 groundwater well sites (each having a shallow and deep part): the Little Arkansas River upstream from the ASR facility near Sedgwick, Kansas (upstream surface-water site 375350097262800), about 0.03 mile (mi) upstream from the residuals return line site; the Little Arkansas River near Sedgwick, Kans. (downstream surface-water site 07144100), about 1.68 mi downstream from the residuals return line site; discharge from the Little Arkansas River ASR facility near Sedgwick, Kansas (residuals return line site 375348097262800); 25S 01 W 07BCCC01 SMW–S11 near CW36 (MW–7 shallow groundwater well

Przewalski’ s Horse ( Equus ferus przewalskii Re-intr oduction in the Great Gobi B Strictly Protected Area: from Species to Ecosystem Conservation

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P. Kaczensky

2007-05-01

Full Text Available The Przewalski’s horse ( Equus ferus przewalskii Po ljakov , 1881, or “T akhi” in Mongolian, became extinct in the wild by the mid 1960’ s. The last recorded sightings of Przewalski’s horses occurred in the Dzungarian Gobi desert in SW Mo ngolia, today’s Great Gobi B Strictly Protected Area (SP A. A re - introduction program was initiated in 1992 and the fi rs t group of captive-born Przewalski’s horses was airlifted to the SPA. Given the logistical challenges associated with such a venture, the initial project focus has been on transport logistics and the well-being of the re-introduced horses. Tod ay, conservation efforts are spread over the entire protected area. Present day ef forts include other mammals, vegetation and the local people. Due to its important symbolic value in Mongolian culture, the Przewalski’ s horse became an important fl agship species for the protected area’s conservation and management.

Diagnostic value of computed tomography, radiography and ultrasonography in metacarpophalangeal joint disorders in horses

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V.M.V. Machado

2016-02-01

Full Text Available In modern society the work and athletic performance of horses has led to a very important animal production sector in which Brazil possesses the third largest horse stock. Among all equine lesions described, metacarpophalangeal (fetlock joint lesions are considered one of the main causes of lameness. Consequently, there is a need to improve the understanding and diagnosis of these injuries. The most efficient imaging diagnostic methods for the fetlock region are computed tomography, radiography and ultrasound. Imaging studies of the anatomical structures involving this joint are extremely important to obtain a more precise diagnose. The present study was performed in order to evaluate the capacity of different imaging diagnostic modalities to detect a variety of lesions in different fetlock structures. Twenty horses (Equus caballus used for horsemanship activities were referred to the Department of Animal Reproduction and Veterinary Radiology of São Paulo State University, Botucatu campus, with clinical signs of metacarpophalangeal joint injuries. Horses were submitted to radiographic and ultrasonographic exam and computed tomography scan. Image analysis revealed a significant capacity of these methods to characterize lesions in this region. However, computed tomography provided broader and better evaluation of lesions in bones and adjacent structures, because it allows the analysis to be performed on three-dimensional projections, with attenuation coefficients (window selections and tissue density measurement through Hounsfield Units (HU.

Quantifying Equid Behavior - A Research Ethogram for Free-Roaming Feral Horses

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Ransom, Jason I.; Cade, Brian S.

2009-01-01

Feral horses (Equus caballus) are globally distributed in free-roaming populations on all continents except Antarctica and occupy a wide range of habitats including forest, grassland, desert, and montane environments. The largest populations occur in Australia and North America and have been the subject of scientific study for decades, yet guidelines and ethograms for feral horse behavioral research are largely absent in the scientific literature. The U.S. Geological Survey (USGS) Fort Collins Science Center conducted research on the influences of the immunocontraceptive porcine zona pellucida (PZP) on feral horse behavior from 2003-2006 in three discrete populations in the American west. These populations were the Little Book Cliffs Wild Horse Range in Colorado, McCullough Peaks Herd Management Area in Wyoming, and Pryor Mountain Wild Horse Range in Montana; the research effort included over 1,800 hours of behavioral observations of 317 adult free-roaming feral horses. An ethogram was developed during the course of this study to facilitate accurate scientific data collection on feral horse behavior, which is often challenging to quantify. By developing this set of discrete behavioral definitions and a set of strict research protocols, scientists were better able to address both applied questions, such as behavioral changes related to fertility control, and theoretical questions, such as understanding networks and dominance hierarchies within social groups of equids.

De Novo Assembly of the Donkey White Blood Cell Transcriptome and a Comparative Analysis of Phenotype-Associated Genes between Donkeys and Horses.

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Xie, Feng-Yun; Feng, Yu-Long; Wang, Hong-Hui; Ma, Yun-Feng; Yang, Yang; Wang, Yin-Chao; Shen, Wei; Pan, Qing-Jie; Yin, Shen; Sun, Yu-Jiang; Ma, Jun-Yu

2015-01-01

Prior to the mechanization of agriculture and labor-intensive tasks, humans used donkeys (Equus africanus asinus) for farm work and packing. However, as mechanization increased, donkeys have been increasingly raised for meat, milk, and fur in China. To maintain the development of the donkey industry, breeding programs should focus on traits related to these new uses. Compared to conventional marker-assisted breeding plans, genome- and transcriptome-based selection methods are more efficient and effective. To analyze the coding genes of the donkey genome, we assembled the transcriptome of donkey white blood cells de novo. Using transcriptomic deep-sequencing data, we identified 264,714 distinct donkey unigenes and predicted 38,949 protein fragments. We annotated the donkey unigenes by BLAST searches against the non-redundant (NR) protein database. We also compared the donkey protein sequences with those of the horse (E. caballus) and wild horse (E. przewalskii), and linked the donkey protein fragments with mammalian phenotypes. As the outer ear size of donkeys and horses are obviously different, we compared the outer ear size-associated proteins in donkeys and horses. We identified three ear size-associated proteins, HIC1, PRKRA, and KMT2A, with sequence differences among the donkey, horse, and wild horse loci. Since the donkey genome sequence has not been released, the de novo assembled donkey transcriptome is helpful for preliminary investigations of donkey cultivars and for genetic improvement.

Are California Sea Lions (Zalophus californianus Sensitive to the Attentional State of their Caretakers?

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Marie Penel

2014-11-01

Full Text Available Human-animal relations appear in various contexts (homes, farms, zoos, aquatic parks, etc. possibly favoring the emergence of the ability to understand heterospecific communication signals in several species. Studies show that dogs (Canis familiaris have developed the ability to attribute attention to humans, reading their body, head and gaze cues. Horses (Equus caballus and other species including African gray parrots (Psittacus erithacus show this ability too. Here, we asked if California sea lions (Zalophus californianus can discriminate the attentional state of their caretakers. Four sea lions were tested in three increasingly complex experiments requiring them to make a choice between an attentive versus an inattentive caretaker. The first test asked whether sea lions could attribute attention to a human facing them versus facing away. In the second test, the caretaker’s head orientation towards the sea lion served as the attentional cue. In the final test, the inattentive caretaker wore dark sunglasses. The results were heterogeneous and showed a higher rate of success than failure in the test 1, but the opposite in test 2. The results in the test 3 were not significant. Furthermore, the latency measures suggested that the subjects did not understand the tasks. It therefore appears that in the situation used here sea lions mainly focused their attention on the experimenter’s body orientation; the head did not seem to be a pertinent cue.

Prevalence of Toxoplasma gondii antibodies in domestic donkeys (Equus asinus) in Durango, Mexico slaughtered for human consumption.

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Alvarado-Esquivel, Cosme; Alvarado-Esquivel, Domingo; Dubey, Jitender P

2015-01-17

Nothing is known about Toxoplasma gondii prevalence in donkeys in Mexico. Meat from donkey is consumed by humans in Mexico and also exported to other countries. We sought to determine the presence of antibodies against T. gondii in 239 domestic donkeys (Equus asinus) for slaughter in Durango, Mexico using the modified agglutination test (MAT). Donkeys were sampled in four premises (trade centers) where donkeys were gather for shipment to abattoirs in other Mexican states. Antibodies to T. gondii were found in 26 (10.9%) of 239 donkeys, with MAT titers of 1:25 in 7, 1:50 in 11, 1:100 in 6, and 1:200 in 2. Seropositive donkeys were found in three (75%) of the four gathering premises studied. Seroprevalence in donkeys varied from 0% to 23.1% among gathering premises. The seroprevalence of T. gondii infection was comparable among donkeys regardless their age, sex or health status. Seropositivity to T. gondii was found in donkeys between 1 to 12 years old. Multivariate analysis showed that seropositivity to T. gondii was associated with the gathering premises (OR = 1.58; 95% CI: 1.11-2.24; P = 0.009). This is the first report of T. gondii infection in donkeys in Mexico. Results indicate that consumption of undercooked or raw meat from T. gondii-infected donkeys is potentially a source of T. gondii infection for humans.

Risk Factors Associated with the Occurrence of Gastrointestinal Helminths among Indigenous Donkeys (Equus asinus in Northeastern Nigeria

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Saleh Mohammed Jajere

2016-01-01

Full Text Available Aim. This survey study was conducted from April 2014 through March 2015 in Bauchi, Yobe, and Gombe states, northeastern Nigeria, to explore the risk factors associated with the occurrence of gastrointestinal helminthosis among indigenous donkeys (Equus asinus. Materials and Methods. A total of six hundred fresh faecal samples were randomly collected from indigenous donkeys of varying age, sex, and settlements. Simple flotation and sedimentation techniques were used for the detection of helminths eggs. Results. Three gastrointestinal nematode parasites were encountered including Strongyle, Parascaris equorum, and Oxyuris equi. An overall prevalence of 98.3% was obtained, of which 78.3%, 40.3%, and 17.5% were, respectively, from Strongyle, Parascaris equorum, and Oxyuris equi. Age, sex, and season were not statistically associated with the risk of helminth infection as were the different study areas (p>0.05. However, body condition score, settlement, anthelminthic medication history, and management practices were significantly associated with the risk of gastrointestinal helminthosis. Statistically high prevalence of helminthic infections was observed in donkeys, with poor (thin body condition, from rural settlements, that were not dewormed and raised under poor management systems (p<0.001. Conclusion. It is concluded from the study that gastrointestinal helminths particularly Strongyle were endemic among the indigenous donkeys in northeastern Nigeria. Further control and preventive measures were discussed.

Mitochondrial DNA analyses revealed low genetic diversity in the endangered Indian wild ass Equus hemionus khur.

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Khaire, Devendra; Atkulwar, Ashwin; Farah, Sameera; Baig, Mumtaz

2017-09-01

The Indian wild ass Equus hemionus khur, belonging to ass-like equid branch, inhabits the dry and arid desert of the Little Rann of Kutch, Gujarat. The E. h. khur is the sole survivor of Asiatic wild ass species/subspecies in South Asia. To provide first ever insights into the genetic diversity, phylogeny, and demography of the endangered Indian wild ass, we sampled 52 free-ranging individuals from the Little Rann of Kutch by using a non-invasive methodology. The sequencing of 230 bp in cytochrome b (Cyt b) and displacement loop (D-loop) region revealed that current ∼4000 extant population of Indian wild ass harbours low genetic diversity. Phylogenetic analyses confirmed that E. h. khur, E. h. onager, and E. h. kulan belong to a single strict monophyletic clade. Therefore, we suggest the delimitation of the five E. hemionus subspecies in vogue to a single species E. hemionus. The application of molecular clock confirmed that the Asiatic wild ass had undergone diversification 0.65 Million years ago. Demographic measurements assessed using a Bayesian skyline plot demonstrated decline in the maternal effective population size of the Indian wild ass during different periods; these periods coincided with the origin and rise of the Indus civilization in the northwest of the Indian subcontinent during the Neolithic. In conclusion, maintaining high genetic diversity in the existing isolated population of 4000 Indian wild asses inhabiting the wild ass sanctuary is important compared with subspecies preservation alone.

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Indian Academy of Sciences (India)

Navya

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Plains zebra (Equus quagga) adrenocortical activity increases during times of large aggregations in the Serengeti ecosystem.

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Seeber, P A; Franz, M; Dehnhard, M; Ganswindt, A; Greenwood, A D; East, M L

2018-04-20

Adverse environmental stimuli (stressors) activate the hypothalamic-pituitary-adrenal axis and contribute to allostatic load. This study investigates the contribution of environmental stressors and life history stage to allostatic load in a migratory population of plains zebras (Equus quagga) in the Serengeti ecosystem, in Tanzania, which experiences large local variations in aggregation. We expected higher fGCM response to the environmental stressors of feeding competition, predation pressure and unpredictable social relationships in larger than in smaller aggregations, and in animals at energetically costly life history stages. As the study was conducted during the 2016 El Niño, we did not expect food quality of forage or a lack of water to strongly affect fGCM responses in the dry season. We measured fecal glucocorticoid metabolite (fGCM) concentrations using an enzyme immunoassay (EIA) targeting 11β-hydroxyetiocholanolone and validated its reliability in captive plains zebras. Our results revealed significantly higher fGCM concentrations 1) in large aggregations than in smaller groupings, and 2) in band stallions than in bachelor males. Concentrations of fGCM were not significantly higher in females at the energetically costly life stage of late pregnancy/lactation. The higher allostatic load of stallions associated with females, than bachelor males is likely caused by social stressors. In conclusion, migratory zebras have elevated allostatic loads in large aggregations that probably result from their combined responses to increased feeding competition, predation pressure and various social stressors. Further research is required to disentangle the contribution of these stressors to allostatic load in migratory populations. Copyright © 2018 Elsevier Inc. All rights reserved.

Pre- and postnatal growth phenomena of Burchell's Zebra Equus Burchelli Antiquorum

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G.L. Smuts

1975-07-01

Full Text Available Between 1969 and 1972 growth data were collected from 175 zebra Equus burchelli antiquorum and 138 zebra embryos and foetuses from the Central District of the Kruger National Park, Republic of South Africa. Statistical analysis of data indicated no significant difference between body mass of adult stallions (range == 267,3 to 373,3 kg; mean = 318,5 kg; n = 57 and adult non-pregnant mares (range = 272,6 to 386,9 kg; mean = 321,6 kg; n = 51 (t = 0,587. The heaviest zebra had a body mass of 429,4 kilogram. This was a pregnant mare carrying a 35,2 kg foetus. Von Bertalanffy growth curves indicated that shoulder heights in young zebra may reach the adult range by one year of age, the adult body mass range is, however, only attained after three years of age. These curves also showed that age classification of free roaming zebra is only reliable up to the age of about two years, after which individual variation is too great. Stallions were significantly taller at the shoulder than mares (mean = 1,8 cm (t = 2,032 and neck thickness was the only body dimension showing visible sexual dimorphism in adults. Here the stallion had a neck girth on average 8,1 cm greater than the mare. Regression equations for estimating body mass from body dimensions were calculated by using a standard logarithmic transformation and fitting a linear regression by the method of least squares and also by undertaking standard straight line linear regression analyses. Exponential curves obtained by the first method indicated that growth was not isometric (not linear and that the ratios of any of the dimensions of length to body mass were con- stantly changing, i.e. growth is allometric. Marked allometric growth differences existed between the two sexes except in the case of the heart girth-body mass relationship. Comparison of growth data from E. b. antiquorum with that of E. b. boehmi from Tanzania (Sachs 1967, indicates that E. b. antiquorum is considerably larger. Body masses

De Novo Assembly of the Donkey White Blood Cell Transcriptome and a Comparative Analysis of Phenotype-Associated Genes between Donkeys and Horses.

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Feng-Yun Xie

Full Text Available Prior to the mechanization of agriculture and labor-intensive tasks, humans used donkeys (Equus africanus asinus for farm work and packing. However, as mechanization increased, donkeys have been increasingly raised for meat, milk, and fur in China. To maintain the development of the donkey industry, breeding programs should focus on traits related to these new uses. Compared to conventional marker-assisted breeding plans, genome- and transcriptome-based selection methods are more efficient and effective. To analyze the coding genes of the donkey genome, we assembled the transcriptome of donkey white blood cells de novo. Using transcriptomic deep-sequencing data, we identified 264,714 distinct donkey unigenes and predicted 38,949 protein fragments. We annotated the donkey unigenes by BLAST searches against the non-redundant (NR protein database. We also compared the donkey protein sequences with those of the horse (E. caballus and wild horse (E. przewalskii, and linked the donkey protein fragments with mammalian phenotypes. As the outer ear size of donkeys and horses are obviously different, we compared the outer ear size-associated proteins in donkeys and horses. We identified three ear size-associated proteins, HIC1, PRKRA, and KMT2A, with sequence differences among the donkey, horse, and wild horse loci. Since the donkey genome sequence has not been released, the de novo assembled donkey transcriptome is helpful for preliminary investigations of donkey cultivars and for genetic improvement.

Poor horse traders: large mammals trade survival for reproduction during the process of feralization

Science.gov (United States)

Grange, Sophie; Duncan, Patrick; Gaillard, Jean-Michel

2009-01-01

We investigated density dependence on the demographic parameters of a population of Camargue horses (Equus caballus), individually monitored and unmanaged for eight years. We also analysed the contributions of individual demographic parameters to changes in the population growth rates. The decrease in resources caused a loss of body condition. Adult male survival was not affected, but the survival of foals and adult females decreased with increasing density. Prime-aged females maintained high reproductive performance at high density, and their survival decreased. The higher survival of adult males compared with females at high density presumably results from higher investment in reproduction by mares. The high fecundity in prime-aged females, even when at high density, may result from artificial selection for high reproductive performance, which is known to have occurred in all the major domestic ungulates. Other studies suggest that feral ungulates including cattle and sheep, as these horses, respond differently from wild ungulates to increases in density, by trading adult survival for reproduction. As a consequence, populations of feral animals should oscillate more strongly than their wild counterparts, since they should be both more invasive (as they breed faster), and more sensitive to harsh environmental conditions (as the population growth rate of long-lived species is consistently more sensitive to a given proportional change in adult survival than to the same change in any other vital rate). If this principle proves to be general, it has important implications for management of populations of feral ungulates. PMID:19324787

Geography and Timing of Cases of Eastern Equine Encephalitis in New York State from 1992 to 2012.

Science.gov (United States)

Oliver, JoAnne; Lukacik, Gary; Kramer, Laura D; Backenson, P Bryon; Sherwood, James A; Howard, John J

2016-04-01

In New York State (NYS), Eastern equine encephalitis (EEE) was first reported in a human in 1971, in horses in 1970, and in pheasants in 1952. Following work for the interval from 1970 to 1991, we identified cases in vertebrates from 1992 to 2012, through a passive surveillance system involving veterinarians in clinical practice, county health departments, and the Departments of Agriculture and Markets, Environmental Conservation, and Health, of the State of New York. During an 11-year hiatus, from 1992 to 2002, no case in any vertebrate was observed. In a re-emergence, from 2003 to 2012, disease occurred in 12 counties, including 7 counties where disease had never been documented. Vertebrate cases included 4 cases in humans and 77 nonhuman occurrences; in 58 horses, Equus ferus caballus L.; 2 deer, Odocoileus virginianus Zimmermann; 6 dogs, Canis familiaris; 10 birds; and 1 flock of pheasants, Phasianus colchicus L. These were the first reported cases in NYS in white-tailed deer, the domestic dog, and in five species of birds: American crow, Corvus brachyrhynchos Brehm; American goldfinch, Carduelis tristis L.; bald eagle, Haliaeetus leucocephalus L.; blue jay, Cyanocitta cristata (L.); and red-tailed hawk, Buteo jamaicensis Gmelin. One crow was dually infected with EEE virus and West Nile virus. The northern, southern, and southeastern borders of the state were newly affected. The geographic area, time periods, and vertebrate species with risk of EEE disease expanded from 1992 to 2012.

Field immobilization of feral 'Judas' donkeys (Equus asinus) by remote injection of medetomidine and ketamine and antagonism with atipamezole.

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Woolnough, Andrew P; Hampton, Jordan O; Campbell, Susan; Lethbridge, Mark R; Boardman, Wayne S J; Sharp, Trudy; Rose, Ken

2012-04-01

The Judas technique is a method used for landscape control of feral donkeys (Equus asinus) in northern Australia. Central to the success of any Judas program is the safe, efficient, and humane attachment of the telemetry device. For feral donkeys, this involves the use of field immobilization. We examine the replacement of the current chemical capture agent, succinylcholine, with contemporary immobilization agents to achieve positive animal welfare outcomes. A combination of medetomidine and ketamine delivered by remote injection from a helicopter was used to capture 14 free-ranging feral donkeys for the fitting of telemetry collars in Western Australia in November 2010. Dose rates of 0.14 mg/kg medetomidine and 4.1 mg/kg ketamine were appropriate to immobilize animals in 9 min (± SD = 3). Mean recovery time (total time in recumbency) was 21 min (± 14). All animals recovered uneventfully after being administered atipamezole, a specific antagonist of medetomidine, intramuscularly at 0.35 mg/kg. Physiologic parameters were recorded during recumbency, with environment-related hyperthermia being the only abnormality recognized. No significant complications were encountered, and this drug combination represents an efficient approach to capturing wild donkeys. This new method allows a rapid, safe, cost-effective approach to the immobilization of feral donkeys for use as Judas animals. This drug combination will replace the relatively inhumane succinylcholine for the field immobilization of feral donkeys.

Značkování u koňovitých (Equidae)

OpenAIRE

TUČKOVÁ, Vladimíra

2012-01-01

This master thesis examined the scent marking behaviour by urine and faeces in four equid species, African wild ass (Equus africanus), Grevy?s zebra (Equus grevyi), Plain zebra (Equus quagga) and Mountain zebra (Equus zebra), in captivity. Data about scent marking were collected during two five-month seasons of behavioural observation of 15 equid herds in 5 Czech Zoos, Zoo Dvůr Králové, Zoo Liberec, Zoo Brno, Zoo Ostrava and Zoo Ústí nad Labem. The study focused mainly on testing several hypo...

Unraveling the effects of selection and demography on immune gene variation in free-ranging plains zebra (Equus quagga) populations.

Science.gov (United States)

Kamath, Pauline L; Getz, Wayne M

2012-01-01

Demography, migration and natural selection are predominant processes affecting the distribution of genetic variation among natural populations. Many studies use neutral genetic markers to make inferences about population history. However, the investigation of functional coding loci, which directly reflect fitness, is critical to our understanding of species' ecology and evolution. Immune genes, such as those of the Major Histocompatibility Complex (MHC), play an important role in pathogen recognition and provide a potent model system for studying selection. We contrasted diversity patterns of neutral data with MHC loci, ELA-DRA and -DQA, in two southern African plains zebra (Equus quagga) populations: Etosha National Park, Namibia, and Kruger National Park, South Africa. Results from neutrality tests, along with observations of elevated diversity and low differentiation across populations, supported previous genus-level evidence for balancing selection at these loci. Despite being low, MHC divergence across populations was significant and may be attributed to drift effects typical of geographically separated populations experiencing little to no gene flow, or alternatively to shifting allele frequency distributions driven by spatially variable and fluctuating pathogen communities. At the DRA, zebra exhibited geographic differentiation concordant with microsatellites and reduced levels of diversity in Etosha due to highly skewed allele frequencies that could not be explained by demography, suggestive of spatially heterogeneous selection and local adaptation. This study highlights the complexity in which selection affects immune gene diversity and warrants the need for further research on the ecological mechanisms shaping patterns of adaptive variation among natural populations.

Seropositivity of Toxoplasma gondii in domestic donkeys (Equus asinus) and isolation of T. gondii from farm cats.

Science.gov (United States)

Dubey, J P; Ness, S L; Kwok, O C H; Choudhary, S; Mittel, L D; Divers, T J

2014-01-17

Donkeys (Equus asinus) are used as both companion and working animals throughout the world and in some countries, their meat and milk are used for human consumption. Here we report the first serological survey of Toxoplasma gondii in donkeys in the United States. Serum samples from 373 donkeys from eight farms in five states were tested for T. gondii antibodies by the modified agglutination test (MAT). Twenty-four of 373 (6.4%) of donkeys were seropositive, with MAT titers ranging from 25 to ≥ 200. All seropositive donkeys were Miniature breed. Seropositivity prevalence was 7.0% in female donkeys (20/282) and 4.1% in male donkeys (4/91). No donkeys less than 24 months of age (129) were seropositive, suggesting postnatal transmission of infection. Domestic cats were present on six of the eight farms. Three cats from one farm had MAT titers of 200. Viable T. gondii was isolated from the hearts of two cats, but not from brain tissues. Genotyping of isolate DNA extracted from culture-derived tachyzoites using 10 PCR-restriction fragment length polymorphism (RFLP) markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, PK1, L358 and Apico loci) revealed that both isolates were clonal Type II (ToxoDB PCR-RFLP genotype #1). This is the first serological survey for T. gondii in donkeys in the United States, and suggests that donkey milk and meat should be considered as a potential source for human infection. The role of barn cats in the transmission of T. gondii to donkeys on farms warrents further investigation. Copyright © 2013 Elsevier B.V. All rights reserved.

Black rhinoceros (Diceros bicornis) and domestic horse (Equus caballus) hindgut microflora demonstrate similar fermentation responses to grape seed extract supplementation in vitro.

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Huntley, N F; Naumann, H D; Kenny, A L; Kerley, M S

2017-10-01

The domestic horse is used as a nutritional model for rhinoceros maintained under human care. The validity of this model for browsing rhinoceros has been questioned due to high prevalence of iron overload disorder (IOD) in captive black rhinoceros (Diceros bicornis), which is associated with high morbidity and mortality. Iron chelators, such as tannins, are under investigation as dietary supplements to ameliorate or prevent IOD in prone species. Polyphenolic compounds variably affect microbial fermentation, so the first objective of this experiment was to evaluate the effects of grape seed extract (GSE; a concentrated source of condensed tannins; CT) on black rhinoceros hindgut fermentation. Equine nutrition knowledge is used to assess supplements for rhinoceros; therefore, the second objective was to evaluate the domestic horse model for black rhinoceros fermentation and compare fermentation responses to GSE using a continuous single-flow in vitro culture system. Two replicated continuous culture experiments were conducted using horse and black rhinoceros faeces as inoculum sources comparing four diets with increasing GSE inclusion (0.0%, 1.3%, 2.7% and 4.0% of diet dry matter). Diet and GSE polyphenolic compositions were determined, and sodium sulphite effect on neutral detergent fibre extraction of CT-containing forages was tested. Increasing GSE inclusion stimulated microbial growth and fermentation, and proportionally increased diet CT concentration and iron-binding capacity. Horse and black rhinoceros hindgut microflora nutrient digestibility and fermentation responses to GSE did not differ, and results supported equine fermentation as an adequate model for microbial fermentation in the black rhinoceros. Interpretation of these results is limited to hindgut fermentation and further research is needed to compare foregut digestibility and nutrient absorption between these two species. Supplementation of GSE in black rhinoceros diets up to 4% is unlikely to adversely affect hindgut nutrient digestibility or microbial viability and fermentation. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Space-Use Patterns of the Asiatic Wild Ass (Equus hemionus): Complementary Insights from Displacement, Recursion Movement and Habitat Selection Analyses.

Science.gov (United States)

Giotto, Nina; Gerard, Jean-François; Ziv, Alon; Bouskila, Amos; Bar-David, Shirli

2015-01-01

The way in which animals move and use the landscape is influenced by the spatial distribution of resources, and is of importance when considering species conservation. We aimed at exploring how landscape-related factors affect a large herbivore's space-use patterns by using a combined approach, integrating movement (displacement and recursions) and habitat selection analyses. We studied the endangered Asiatic wild ass (Equus hemionus) in the Negev Desert, Israel, using GPS monitoring and direct observation. We found that the main landscape-related factors affecting the species' space-use patterns, on a daily and seasonal basis, were vegetation cover, water sources and topography. Two main habitat types were selected: high-elevation sites during the day (specific microclimate: windy on warm summer days) and streambed surroundings during the night (coupled with high vegetation when the animals were active in summer). Distribution of recursion times (duration between visits) revealed a 24-hour periodicity, a pattern that could be widespread among large herbivores. Characterizing frequently revisited sites suggested that recursion movements were mainly driven by a few landscape features (water sources, vegetation patches, high-elevation points), but also by social factors, such as territoriality, which should be further explored. This study provided complementary insights into the space-use patterns of E. hemionus. Understanding of the species' space-use patterns, at both large and fine spatial scale, is required for developing appropriate conservation protocols. Our approach could be further applied for studying the space-use patterns of other species in heterogeneous landscapes.

The Responses of Young Domestic Horses to Human-Given Cues

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Proops, Leanne; Rayner, Jenny; Taylor, Anna M.; McComb, Karen

2013-01-01

It has been suggested that the process of domestication, at least in some species, has led to an innate predisposition to be skilled at reading human communicative and attentional cues. Adult domestic horses (Equus caballus) are highly sensitive to subtle bodily cues when determining if a person is attending to them but they are less adept at using human communicative cues in object choice tasks. Here we provide the first study into the ontogeny of such skills in order to gain insights into the mechanisms underlying these abilities. Compared with adult horses, youngsters under the age of three could use body orientation but not more subtle cues such as head movement and open/closed eyes to correctly choose an attentive person to approach for food. Across two object choice experiments, the performance of young horses was comparable to that of adult horses – subjects were able to correctly choose a rewarded bucket using marker placement, pointing and touching cues but could not use body orientation, gaze, elbow pointing or tapping cues. Taken together these results do not support the theory that horses possess an innate predisposition to be particularly skilled at using human cues. Horses' ability to determine whether humans are attending to them using subtle body cues appears to require significant experience to fully develop and their perhaps less remarkable use of limited cues in object choice tasks, although present at a much earlier age, is likely to reflect a more general learning ability related to stimulus enhancement rather than a specific ‘human-reading’ skill. PMID:23840572

OAS1 polymorphisms are associated with susceptibility to West Nile encephalitis in horses.

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Jonathan J Rios

Full Text Available West Nile virus, first identified within the United States in 1999, has since spread across the continental states and infected birds, humans and domestic animals, resulting in numerous deaths. Previous studies in mice identified the Oas1b gene, a member of the OAS/RNASEL innate immune system, as a determining factor for resistance to West Nile virus (WNV infection. A recent case-control association study described mutations of human OAS1 associated with clinical susceptibility to WNV infection. Similar studies in horses, a particularly susceptible species, have been lacking, in part, because of the difficulty in collecting populations sufficiently homogenous in their infection and disease states. The equine OAS gene cluster most closely resembles the human cluster, with single copies of OAS1, OAS3 and OAS2 in the same orientation. With naturally occurring susceptible and resistant sub-populations to lethal West Nile encephalitis, we undertook a case-control association study to investigate whether, similar to humans (OAS1 and mice (Oas1b, equine OAS1 plays a role in resistance to severe WNV infection. We identified naturally occurring single nucleotide mutations in equine (Equus caballus OAS1 and RNASEL genes and, using Fisher's Exact test, we provide evidence that mutations in equine OAS1 contribute to host susceptibility. Virtually all of the associated OAS1 polymorphisms were located within the interferon-inducible promoter, suggesting that differences in OAS1 gene expression may determine the host's ability to resist clinical manifestations associated with WNV infection.

The Brain of the Domestic Bos taurus: Weight, Encephalization and Cerebellar Quotients, and Comparison with Other Domestic and Wild Cetartiodactyla.

Science.gov (United States)

Ballarin, Cristina; Povinelli, Michele; Granato, Alberto; Panin, Mattia; Corain, Livio; Peruffo, Antonella; Cozzi, Bruno

2016-01-01

The domestic bovine Bos taurus is raised worldwide for meat and milk production, or even for field work. However the functional anatomy of its central nervous system has received limited attention and most of the reported data in textbooks and reviews are derived from single specimens or relatively old literature. Here we report information on the brain of Bos taurus obtained by sampling 158 individuals, 150 of which at local abattoirs and 8 in the dissecting room, these latter subsequently formalin-fixed. Using body weight and fresh brain weight we calculated the Encephalization Quotient (EQ), and Cerebellar Quotient (CQ). Formalin-fixed brains sampled in the necropsy room were used to calculate the absolute and relative weight of the major components of the brain. The data that we obtained indicate that the domestic bovine Bos taurus possesses a large, convoluted brain, with a slightly lower weight than expected for an animal of its mass. Comparisons with other terrestrial and marine members of the order Cetartiodactyla suggested close similarity with other species with the same feeding adaptations, and with representative baleen whales. On the other hand differences with fish-hunting toothed whales suggest separate evolutionary pathways in brain evolution. Comparison with the other large domestic herbivore Equus caballus (belonging to the order Perissodactyla) indicates that Bos taurus underwent heavier selection of bodily traits, which is also possibly reflected in a comparatively lower EQ than in the horse. The data analyzed suggest that the brain of domestic bovine is potentially interesting for comparative neuroscience studies and may represents an alternative model to investigate neurodegeneration processes.

The MC1R and ASIP Coat Color Loci May Impact Behavior in the Horse

Science.gov (United States)

Jacobs, Lauren N.; Staiger, Elizabeth A.; Albright, Julia D.

2016-01-01

Shared signaling pathways utilized by melanocytes and neurons result in pleiotropic traits of coat color and behavior in many mammalian species. For example, in humans polymorphisms at MC1R cause red hair, increased heat sensitivity, and lower pain tolerance. In deer mice, rats, and foxes, ASIP polymorphisms causing black coat color lead to more docile demeanors and reduced activity. Horse (Equus caballus) base coat color is primarily determined by polymorphisms at the Melanocortin-1 Receptor (MC1R) and Agouti Signaling Protein (ASIP) loci, creating a black, bay, or chestnut coat. Our goal was to investigate correlations between genetic loci for coat color and temperament traits in the horse. We genotyped a total of 215 North American Tennessee Walking Horses for the 2 most common alleles at the MC1R (E/e) and ASIP (A/a) loci using previously published PCR and RFLP methods. The horses had a mean age of 10.5 years and comprised 83 geldings, 25 stallions, and 107 mares. To assess behavior, we adapted a previously published survey for handlers to score horses from 1 to 9 on 20 questions related to specific aspects of temperament. We utilized principle component analysis to combine the individual survey scores into 4 factors of variation in temperament phenotype. A factor component detailing self-reliance correlated with genotypes at the ASIP locus; black mares (aa) were more independent than bay mares (A_) (P = 0.0063). These findings illuminate a promising and novel animal model for future study of neuroendocrine mechanisms in complex behavioral phenotypes. PMID:26884605

Geographic variability of Escherichia coli ribotypes from animals in Idaho and Georgia.

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Hartel, Peter G; Summer, Jacob D; Hill, Jennifer L; Collins, J Victoria; Entry, James A; Segars, William I

2002-01-01

Several genotypic methods have been developed for determining the host origin of fecal bacteria in contaminated waters. Some of these methods rely on a host origin database to identify environmental isolates. It is not well understood to what degree these host origin isolates are geographically variable (i.e., cosmopolitan or endemic). This is important because a geographically limited host origin database may or may not be universally applicable. The objective of our study was to use one genotypic method, ribotyping, to determine the geographic variability of the fecal bacterium, Escherichia coli, from one location in Idaho and three locations in Georgia for cattle (Bos taurus), horse (Equus caballus), swine (Sus scrofa), and chicken (Gallus gallus domesticus). A total of 568 fecal E. coli isolates from Kimberly, ID (125 isolates), Athens, GA (210 isolates), Brunswick, GA (102 isolates), and Tifton, GA (131 isolates), yielded 213 ribotypes. The percentage of ribotype sharing within an animal species increased with decreased distance between geographic locations for cattle and horses, but not for swine and chicken. When the E. coli ribotypes among the four host species were compared at one location, the percent of unshared ribotypes was 86, 89, 81, and 79% for Kimberly, Athens, Brunswick, and Tifton, respectively. These data suggest that there is good ribotype separation among host animal species at each location. The ability to match environmental isolates to a host origin database may depend on a large number of environmental and host origin isolates that ideally are not geographically separated.

Ghosts of yellowstone: multi-decadal histories of wildlife populations captured by bones on a modern landscape.

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Joshua H Miller

Full Text Available Natural accumulations of skeletal material (death assemblages have the potential to provide historical data on species diversity and population structure for regions lacking decades of wildlife monitoring, thereby contributing valuable baseline data for conservation and management strategies. Previous studies of the ecological and temporal resolutions of death assemblages from terrestrial large-mammal communities, however, have largely focused on broad patterns of community composition in tropical settings. Here, I expand the environmental sampling of large-mammal death assemblages into a temperate biome and explore more demanding assessments of ecological fidelity by testing their capacity to record past population fluctuations of individual species in the well-studied ungulate community of Yellowstone National Park (Yellowstone. Despite dramatic ecological changes following the 1988 wildfires and 1995 wolf re-introduction, the Yellowstone death assemblage is highly faithful to the living community in species richness and community structure. These results agree with studies of tropical death assemblages and establish the broad capability of vertebrate remains to provide high-quality ecological data from disparate ecosystems and biomes. Importantly, the Yellowstone death assemblage also correctly identifies species that changed significantly in abundance over the last 20 to ∼80 years and the directions of those shifts (including local invasions and extinctions. The relative frequency of fresh versus weathered bones for individual species is also consistent with documented trends in living population sizes. Radiocarbon dating verifies the historical source of bones from Equus caballus (horse: a functionally extinct species. Bone surveys are a broadly valuable tool for obtaining population trends and baseline shifts over decadal-to-centennial timescales.

How grazing affects soil quality of soils formed in the glaciated northeastern United States.

Science.gov (United States)

Cox, Alissa H; Amador, José A

2018-02-21

Historically, much of the New England landscape was converted to pasture for grazing animals and harvesting hay. Both consumer demand for local sustainably produced food, and the number of small farms is increasing in RI, highlighting the importance of characterizing the effects livestock have on the quality of pasture soils. To assess how livestock affect pasture on Charlton and Canton soils series in RI, we examined soil quality in farms raising beef cattle (Bos taurus), sheep (Ovis aries), and horses (Equus ferus caballus), using hayed pastures as a control. We sampled three pastures per livestock type and three control hayed pastures in May, August, and October 2012. Hay fields and pastures grazed by sheep had statistically significant (P soil quality than pastures grazed by beef cattle or horses. This was driven by parameters including penetration resistance, bulk density, aggregate stability, and infiltration rate. Hayfields also showed higher soil quality measures than grazed pastures for organic matter content and active C. In addition, significant differences in nitrate and phosphate concentrations were observed among livestock types. Respiration and infiltration rates, pH, and ammonium concentrations, on the other hand, did not differ significantly among pasture types. When all soil quality indicators in this study were weighed equally, soil quality scores followed the order: hay > sheep > beef cattle > horses. The results of our study provide baseline data on the effect different types of livestock have on pasture soil quality in RI, which may be useful in making sound land use and agricultural management decisions.

Unraveling the effects of selection and demography on immune gene variation in free-ranging plains zebra (Equus quagga populations.

Directory of Open Access Journals (Sweden)

Pauline L Kamath

Full Text Available Demography, migration and natural selection are predominant processes affecting the distribution of genetic variation among natural populations. Many studies use neutral genetic markers to make inferences about population history. However, the investigation of functional coding loci, which directly reflect fitness, is critical to our understanding of species' ecology and evolution. Immune genes, such as those of the Major Histocompatibility Complex (MHC, play an important role in pathogen recognition and provide a potent model system for studying selection. We contrasted diversity patterns of neutral data with MHC loci, ELA-DRA and -DQA, in two southern African plains zebra (Equus quagga populations: Etosha National Park, Namibia, and Kruger National Park, South Africa. Results from neutrality tests, along with observations of elevated diversity and low differentiation across populations, supported previous genus-level evidence for balancing selection at these loci. Despite being low, MHC divergence across populations was significant and may be attributed to drift effects typical of geographically separated populations experiencing little to no gene flow, or alternatively to shifting allele frequency distributions driven by spatially variable and fluctuating pathogen communities. At the DRA, zebra exhibited geographic differentiation concordant with microsatellites and reduced levels of diversity in Etosha due to highly skewed allele frequencies that could not be explained by demography, suggestive of spatially heterogeneous selection and local adaptation. This study highlights the complexity in which selection affects immune gene diversity and warrants the need for further research on the ecological mechanisms shaping patterns of adaptive variation among natural populations.

Non-invasive Pregnancy Diagnosis from Urine by the Cuboni Reaction and the Barium Chloride Test in Donkeys (Equus asinus) and Alpacas (Vicugna pacos).

Science.gov (United States)

Kubátová, A; Fedorova, T; Skálová, I; Hyniová, L

2016-09-01

The aim of the research was to evaluate two chemical tests for non-invasive pregnancy diagnosis from urine, the Cuboni reaction and the barium chloride test, in donkeys (Equus asinus) and alpacas (Vicugna pacos). The research was carried out from April 2013 to September 2014. Urine samples were collected on five private Czech farms from 18 jennies and 12 alpaca females. Urine was collected non-invasively into plastic cups fastened on a telescopic rod, at 6-9 week intervals. In total, 60 and 54 urine samples from alpacas and jennies, respectively, were collected. The Cuboni reaction was performed by the State Veterinary Institute Prague. The barium chloride test was done with 5 ml of urine mixed together with 5 ml of 1% barium chloride solution. Results of the Cuboni reaction were strongly influenced by the reproductive status of jennies; the test was 100% successful throughout the second half of pregnancy. However, no relationship was found between the real reproductive status of alpaca females and results of the Cuboni reaction. It was concluded that the barium chloride test is not suitable for pregnancy diagnosis either in donkeys, due to significant influence of season on the results, or in alpacas, because no relationship between results of the test and the reproductive status of alpaca females was found. In conclusion, the Cuboni reaction has potential to become a standard pregnancy diagnostic method in donkeys.

50 CFR 17.11 - Endangered and threatened wildlife.

Science.gov (United States)

2010-10-01

... Argentina Entire E 15 NA NA Armadillo, pink fairy Chlamyphorus truncatus Argentina ......do E 3 NA NA Ass, African wild Equus asinus Somalia, Sudan, Ethiopia ......do E 3, 22 NA NA Ass, Asian wild Equus hemionus...

EquiFACS: The Equine Facial Action Coding System.

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Jen Wathan

Full Text Available Although previous studies of horses have investigated their facial expressions in specific contexts, e.g. pain, until now there has been no methodology available that documents all the possible facial movements of the horse and provides a way to record all potential facial configurations. This is essential for an objective description of horse facial expressions across a range of contexts that reflect different emotional states. Facial Action Coding Systems (FACS provide a systematic methodology of identifying and coding facial expressions on the basis of underlying facial musculature and muscle movement. FACS are anatomically based and document all possible facial movements rather than a configuration of movements associated with a particular situation. Consequently, FACS can be applied as a tool for a wide range of research questions. We developed FACS for the domestic horse (Equus caballus through anatomical investigation of the underlying musculature and subsequent analysis of naturally occurring behaviour captured on high quality video. Discrete facial movements were identified and described in terms of the underlying muscle contractions, in correspondence with previous FACS systems. The reliability of others to be able to learn this system (EquiFACS and consistently code behavioural sequences was high--and this included people with no previous experience of horses. A wide range of facial movements were identified, including many that are also seen in primates and other domestic animals (dogs and cats. EquiFACS provides a method that can now be used to document the facial movements associated with different social contexts and thus to address questions relevant to understanding social cognition and comparative psychology, as well as informing current veterinary and animal welfare practices.

The Brain of the Domestic Bos taurus: Weight, Encephalization and Cerebellar Quotients, and Comparison with Other Domestic and Wild Cetartiodactyla.

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Cristina Ballarin

Full Text Available The domestic bovine Bos taurus is raised worldwide for meat and milk production, or even for field work. However the functional anatomy of its central nervous system has received limited attention and most of the reported data in textbooks and reviews are derived from single specimens or relatively old literature. Here we report information on the brain of Bos taurus obtained by sampling 158 individuals, 150 of which at local abattoirs and 8 in the dissecting room, these latter subsequently formalin-fixed. Using body weight and fresh brain weight we calculated the Encephalization Quotient (EQ, and Cerebellar Quotient (CQ. Formalin-fixed brains sampled in the necropsy room were used to calculate the absolute and relative weight of the major components of the brain. The data that we obtained indicate that the domestic bovine Bos taurus possesses a large, convoluted brain, with a slightly lower weight than expected for an animal of its mass. Comparisons with other terrestrial and marine members of the order Cetartiodactyla suggested close similarity with other species with the same feeding adaptations, and with representative baleen whales. On the other hand differences with fish-hunting toothed whales suggest separate evolutionary pathways in brain evolution. Comparison with the other large domestic herbivore Equus caballus (belonging to the order Perissodactyla indicates that Bos taurus underwent heavier selection of bodily traits, which is also possibly reflected in a comparatively lower EQ than in the horse. The data analyzed suggest that the brain of domestic bovine is potentially interesting for comparative neuroscience studies and may represents an alternative model to investigate neurodegeneration processes.

Phylogenetic relationships among Perissodactyla: secretoglobin 1A1 gene duplication and triplication in the Equidae family.

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Côté, Olivier; Viel, Laurent; Bienzle, Dorothee

2013-12-01

Secretoglobin family 1A member 1 (SCGB 1A1) is a small anti-inflammatory and immunomodulatory protein that is abundantly secreted in airway surface fluids. We recently reported the existence of three distinct SCGB1A1 genes in the domestic horse genome as opposed to the single gene copy consensus present in other mammals. The origin of SCGB1A1 gene triplication and the evolutionary relationship of the three genes amongst Equidae family members are unknown. For this study, SCGB1A1 genomic data were collected from various Equus individuals including E. caballus, E. przewalskii, E. asinus, E. grevyi, and E. quagga. Three SCGB1A1 genes in E. przewalskii, two SCGB1A1 genes in E. asinus, and a single SCGB1A1 gene in E. grevyi and E. quagga were identified. Sequence analysis revealed that the non-synonymous nucleotide substitutions between the different equid genes coded for 17 amino acid changes. Most of these changes localized to the SCGB 1A1 central cavity that binds hydrophobic ligands, suggesting that this area of SCGB 1A1 evolved to accommodate diverse molecular interactions. Three-dimensional modeling of the proteins revealed that the size of the SCGB 1A1 central cavity is larger than that of SCGB 1A1A. Altogether, these findings suggest that evolution of the SCGB1A1 gene may parallel the separation of caballine and non-caballine species amongst Equidae, and may indicate an expansion of function for SCGB1A1 gene products. Copyright © 2013 Elsevier Inc. All rights reserved.

Contribuição ao estudo do funículo espermático em eqüinos sem raça definida (Equus caballus, L.

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André Luiz Quagliatto Santos

1992-06-01

Full Text Available Utilizando 35 pares de funículos esperméticos de eqüinos sem raça definida, estudaram-se os aspectos histológicos dos envoltórios funiculares, dos vasos arteriais e venosos e dos tecidos intervasculares, assim como o seu arranjo vascular e o comprimento do segmento da artéria testicular nele contido.

Adaptive molecular evolution of the Major Histocompatibility Complex genes, DRA and DQA, in the genus Equus.

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Kamath, Pauline L; Getz, Wayne M

2011-05-18

Major Histocompatibility Complex (MHC) genes are central to vertebrate immune response and are believed to be under balancing selection by pathogens. This hypothesis has been supported by observations of extremely high polymorphism, elevated nonsynonymous to synonymous base pair substitution rates and trans-species polymorphisms at these loci. In equids, the organization and variability of this gene family has been described, however the full extent of diversity and selection is unknown. As selection is not expected to act uniformly on a functional gene, maximum likelihood codon-based models of selection that allow heterogeneity in selection across codon positions can be valuable for examining MHC gene evolution and the molecular basis for species adaptations. We investigated the evolution of two class II MHC genes of the Equine Lymphocyte Antigen (ELA), DRA and DQA, in the genus Equus with the addition of novel alleles identified in plains zebra (E. quagga, formerly E. burchelli). We found that both genes exhibited a high degree of polymorphism and inter-specific sharing of allele lineages. To our knowledge, DRA allelic diversity was discovered to be higher than has ever been observed in vertebrates. Evidence was also found to support a duplication of the DQA locus. Selection analyses, evaluated in terms of relative rates of nonsynonymous to synonymous mutations (dN/dS) averaged over the gene region, indicated that the majority of codon sites were conserved and under purifying selection (dN

Adaptive molecular evolution of the Major Histocompatibility Complex genes, DRA and DQA, in the genus Equus

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Getz Wayne M

2011-05-01

Full Text Available Abstract Background Major Histocompatibility Complex (MHC genes are central to vertebrate immune response and are believed to be under balancing selection by pathogens. This hypothesis has been supported by observations of extremely high polymorphism, elevated nonsynonymous to synonymous base pair substitution rates and trans-species polymorphisms at these loci. In equids, the organization and variability of this gene family has been described, however the full extent of diversity and selection is unknown. As selection is not expected to act uniformly on a functional gene, maximum likelihood codon-based models of selection that allow heterogeneity in selection across codon positions can be valuable for examining MHC gene evolution and the molecular basis for species adaptations. Results We investigated the evolution of two class II MHC genes of the Equine Lymphocyte Antigen (ELA, DRA and DQA, in the genus Equus with the addition of novel alleles identified in plains zebra (E. quagga, formerly E. burchelli. We found that both genes exhibited a high degree of polymorphism and inter-specific sharing of allele lineages. To our knowledge, DRA allelic diversity was discovered to be higher than has ever been observed in vertebrates. Evidence was also found to support a duplication of the DQA locus. Selection analyses, evaluated in terms of relative rates of nonsynonymous to synonymous mutations (dN/dS averaged over the gene region, indicated that the majority of codon sites were conserved and under purifying selection (dN dS. However, the most likely evolutionary codon models allowed for variable rates of selection across codon sites at both loci and, at the DQA, supported the hypothesis of positive selection acting on specific sites. Conclusions Observations of elevated genetic diversity and trans-species polymorphisms supported the conclusion that balancing selection may be acting on these loci. Furthermore, at the DQA, positive selection was

Estimation and management of genetic diversity in small populations of plains zebra (Equus quagga) in KwaZulu-Natal, South Africa.

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Bowland, A E.; Bishop, K S.; Taylor, P J.; Lamb, J; van der Bank, F H.; van Wyk, E; York, D

2001-06-01

Plains zebras (Equus quagga antiquorum) occur in few large, but many small, isolated populations in KwaZulu-Natal. Problems identified in small populations include reduced striping patterns on hind quarters, smaller size, elevated mortality rates and high number of still-births. Inbreeding may be implicated. Population viability analysis (PVA) was conducted with a computer model (VORTEX), and DNA and allozyme analyses were conducted to test the findings of the model. Using standard methods, DNA (PCR-RAPD) and allozyme diversity was assessed in blood samples from 72 plains zebra from four KwaZulu-Natal Nature Conservation Services (KZN-NCS) protected areas: Umfolozi Game Reserve (UGR), Albert Falls (AFNR), Vernon Crookes (VCNR) and Harold Johnson (HJNR) Nature Reserves. Populations of the latter three, small-sized (9-110 individuals) populations were seeded from the same source population (UGR: current population of 2000) during the past 25 years. Information from PCR-RAPD and allozyme analyses were compared with each other as well as to that predicted by population genetic modelling (using VORTEX). Allozyme heterozygosities were consistently high in all populations (12.1-12.9%), with no observable losses associated with reduced population size. On the other hand, percentage loss of polymorphism (20-39%) calculated from the PCR-RAPD study appeared to be positively correlated with the loss of heterozygosity predicted by population viability analysis (PVA), and negatively correlated with population size. On the basis of the above results, a policy of translocation was advocated for small, intensely managed populations of zebras, whereby a harem should be translocated every five years for a population size of nine (HJNR), while for a population size of 110 (VCNR) translocations should take place every 15 years if heterozygosity is to be maintained at more than 90% within each population over 100 years.

Influence of the cardiac glycoside digoxin on cardiac troponin I, acid-base and electrolyte balance, and haematobiochemical profiles in healthy donkeys (Equus asinus).

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Tharwat, Mohamed; Al-Sobayil, Fahd

2014-03-12

The effect of digoxin administration on the serum concentration of the cardiac troponin I (cTnI) has not been reported to date in equidae. This study was therefore designed to evaluate the effect of digoxin on cardiac cell damage in donkeys (Equus asinus) as assessed by cTnI, acid-base and electrolyte balance and haematobiochemical profiles. Ten clinically healthy donkeys were given an IV infusion of digoxin at a dose of 14 μg/kg. Blood samples were collected from the donkeys up through 72 h post-injection. Three of the donkeys exhibited increased heart and respiratory rates post-injection. In the other seven animals, the heart and respiratory rates were lower 4 h post-injection. The serum digoxin concentration increased significantly at many time points after injection. The serum concentration of cTnI did not differ significantly between pre- and post-injection. An increase in blood pH was noted at 3 h after digoxin injection. There were also increases in PO2 and in oxygen saturation. Decreases in PCO2 at 2 to 48 h post-injection as well as a decrease in blood lactate at 4 h post-injection were observed. The serum concentration of glucose remained significantly elevated at all-time points after digoxin injection. It is concluded that administration of digoxin to healthy donkeys (14 μg/kg) did not result in elevations of serum cTnI concentration, signs of digoxin intoxication, ECG abnormalities and did not increase serum concentrations of blood urea nitrogen and creatinine.

Foaling rates in feral horses treated with the immunocontraceptive porcine zona pellucida

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Ransom, J.I.; Roelle, J.E.; Cade, B.S.; Coates-Markle, L.; Kane, A.J.

2011-01-01

Locally abundant feral horses (Equus caballus) can rapidly deplete available resources. Fertility control agents present promising nonlethal tools for reducing their population growth rates. We tested the effect of 2 forms of the immunocontraceptive porcine zona pellucida (PZP) on foaling rates in 3 populations of feral horses in the western United States. A liquid form requiring annual boosters was administered at Little Book Cliffs Wild Horse Range, Mesa County (CO), and Pryor Mountain Wild Horse Range, Bighorn County (WY) and Carbon County (MT), and a time-release pellet form designed to produce 2 yr of infertility was administered at McCullough Peaks Herd Management Area, Park County (WY). Average foaling rates (foals born/mare-yr) from direct observation of untreated and treated female horses (mares), 2004-2008, were 60.1% (n = 153 mare-yr) versus 6.6% (n = 91 mare-yr) at Little Book Cliffs, and 62.8% (n = 129 mare-yr) versus 17.7% (n = 79 mare-yr) at Pryor Mountain, respectively. At McCullough Peaks, mean annual foaling rates from 2006 to 2008 were 75.0% (n = 48 mare-yr) for untreated mares and 31.7% (n = 101 mare-yr) for treated mares. Controlling for age of mares and pretreatment differences in fertility, PZP reduced foaling rates in all 3 herds. The pellets used at McCullough Peaks (produced by cold evaporation) were less effective than pellets used in a previous trial and produced by heat extrusion. Immunocontraception with PZP may be a useful tool in reducing fertility rates in some western United States feral horse herds, but population growth reduction will depend on timely access to mares for inoculation and the proportion of mares that can be successfully treated. ?? 2011 The Wildlife Society.

Some maternal lineages of domestic horses may have origins in East Asia revealed with further evidence of mitochondrial genomes and HVR-1 sequences

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Hongying Ma

2018-06-01

Full Text Available Objectives There are large populations of indigenous horse (Equus caballus in China and some other parts of East Asia. However, their matrilineal genetic diversity and origin remained poorly understood. Using a combination of mitochondrial DNA (mtDNA and hypervariable region (HVR-1 sequences, we aim to investigate the origin of matrilineal inheritance in these domestic horses. Methods To investigate patterns of matrilineal inheritance in domestic horses, we conducted a phylogenetic study using 31 de novo mtDNA genomes together with 317 others from the GenBank. In terms of the updated phylogeny, a total of 5,180 horse mitochondrial HVR-1 sequences were analyzed. Results Eightteen haplogroups (Aw-Rw were uncovered from the analysis of the whole mitochondrial genomes. Most of which have a divergence time before the earliest domestication of wild horses (about 5,800 years ago and during the Upper Paleolithic (35–10 KYA. The distribution of some haplogroups shows geographic patterns. The Lw haplogroup contained a significantly higher proportion of European horses than the horses from other regions, while haplogroups Jw, Rw, and some maternal lineages of Cw, have a higher frequency in the horses from East Asia. The 5,180 sequences of horse mitochondrial HVR-1 form nine major haplogroups (A-I. We revealed a corresponding relationship between the haplotypes of HVR-1 and those of whole mitochondrial DNA sequences. The data of the HVR-1 sequences also suggests that Jw, Rw, and some haplotypes of Cw may have originated in East Asia while Lw probably formed in Europe. Conclusions Our study supports the hypothesis of the multiple origins of the maternal lineage of domestic horses and some maternal lineages of domestic horses may have originated from East Asia.

Eighty years of cooperative water science

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Stone, Mandy L.

2017-05-09

The Equus Beds aquifer in south-central Kansas is a primary water source for the city of Wichita. The Equus Beds aquifer storage and recovery (ASR) project was developed to help the city of Wichita meet increasing current and future demands. The Equus Beds ASR project is a recent part of an 80-year cooperative water science effort with the city of Wichita. The U.S. Geological Survey (USGS) Kansas Water Science Center characterizes river and aquifer water-quality and quantity and evaluates changes that may or may not be related to ASR. The USGS data are used by the city of Wichita to make informed management decisions, satisfy regulatory requirements, and serve as a baseline to detect any subsequent changes that may be related to ASR.

Physiological response to chemical immobilization: a case study of etorphine-azaperone in free-ranging plains zebra (Equus quagga in Kenya

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Francesca Vitali

2018-06-01

Full Text Available Predictable immobilization of wild zebras is challenging and there is massive variation in opiate response within different species. Etorphine combined with azaperone is considered the protocol of choice, but no studies have investigated the physiological response to this procedure of immobilization in plains zebras.   Eleven free-ranging plains zebras (Equus quagga were immobilized in Kenya using a combination of etorphine 0.019 ± 0.003 mg/kg and azaperone 0.27 ± 0.05 mg/kg administered intramuscularly with a projectile dart. After recumbency, an arterial sample was performed for blood gas analysis and physiological parameters were recorded every five minutes. Descriptive scores were given to the exertion resulting from high-speed chasing and to the quality of induction, immobilization and recovery. Diprenorphine or naltrexone were used for opioid antagonism.   In all zebras, the combination induced quick inductions within 3.5 ± 0.8 minutes and provided reliable recumbencies without attempts to stand for the entire duration of the immobilization. The average heart rates, respiratory rates and mean arterial blood pressure recorded were 102 ± 42 beats/minute, 18 ± 4 breaths/minute and 145 ± 28 mmHg respectively. Arterial gas analyses demonstrated mild to severe and partially compensated metabolic acidosis and hypoxia, while electrolytes were within equids range. In particular, higher exertion levels during the chasing were significantly correlated to worse immobilization scores (p=0.008 and hyperthermia occurrence (p=0.0012 and non-significantly to more severe acidosis. Recoveries from anaesthesia were smooth, on average 121 ± 38 seconds after diprenorphine/naltrexone administration.             Etorphine-azaperone combination produced physiological alterations in free-ranging plains zebra such as tachycardia, hypertension, metabolic acidosis and hypoxemia. However, these preliminary results indicate that high-speed chase

A southern African origin and cryptic structure in the highly mobile plains zebra.

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Pedersen, Casper-Emil T; Albrechtsen, Anders; Etter, Paul D; Johnson, Eric A; Orlando, Ludovic; Chikhi, Lounes; Siegismund, Hans R; Heller, Rasmus

2018-03-01

The plains zebra (Equus quagga) is an ecologically important species of the African savannah. It is also one of the most numerous and widely distributed ungulates, and six subspecies have been described based on morphological variation. However, the within-species evolutionary processes have been difficult to resolve due to its high mobility and a lack of consensus regarding the population structure. We obtained genome-wide DNA polymorphism data from more than 167,000 loci for 59 plains zebras from across the species range, encompassing all recognized extant subspecies, as well as three mountain zebras (Equus zebra) and three Grevy's zebras (Equus grevyi). Surprisingly, the population genetic structure does not mirror the morphology-based subspecies delineation, underlining the dangers of basing management units exclusively on morphological variation. We use demographic modelling to provide insights into the past phylogeography of the species. The results identify a southern African location as the most likely source region from which all extant populations expanded around 370,000 years ago. We show evidence for inclusion of the extinct and phenotypically divergent quagga (Equus quagga quagga) in the plains zebra variation and reveal that it was less divergent from the other subspecies than the northernmost (Ugandan) extant population.

Equus quagga

African Journals Online (AJOL)

FIGURE 3. 0. Family composition of 4 zebra populations. Solid line: total family size; .... stable, had a common sleeping ground where they stayed for the night and ..... because of a certain amount of segregation of stallion groups and families.

Shedding of Clostridium difficile PCR ribotype 078 by zoo animals, and report of an unstable metronidazole-resistant isolate from a zebra foal (Equus quagga burchellii).

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Álvarez-Pérez, Sergio; Blanco, José L; Martínez-Nevado, Eva; Peláez, Teresa; Harmanus, Celine; Kuijper, Ed; García, Marta E

2014-03-14

Clostridium difficile is an emerging and potentially zoonotic pathogen, but its prevalence in most animal species, including exhibition animals, is currently unknown. In this study we assessed the prevalence of faecal shedding of C. difficile by zoo animals, and determined the ribotype, toxin profile and antimicrobial susceptibility of recovered isolates. A total of 200 samples from 40 animal species (36.5% of which came from plains zebra, Equus quagga burchellii) were analysed. C. difficile was isolated from 7 samples (3.5% of total), which came from the following animal species: chimpanzee (Pan troglodytes troglodytes), dwarf goat (Capra hircus), and Iberian ibex (Capra pyrenaica hispanica), with one positive sample each; and plains zebra, with 4 positive samples from 3 different individuals. Most recovered isolates (4/7, 57.1%) belonged to the epidemic PCR ribotype 078, produced toxins A and B, and had the genes encoding binary toxin (i.e. A(+)B(+)CDT(+) isolates). The remaining three isolates belonged to PCR ribotypes 039 (A(-)B(-)CDT(-)), 042 (A(+)B(+)CDT(-)) and 110 (A(-)B(+)CDT(-)). Regardless of their ribotype, all isolates displayed high-level resistance to the fluoroquinolones ciprofloxacin, enrofloxacin and levofloxacin. Some isolates were also resistant to meropenem and/or ertapenem. A ribotype 078 isolate recovered from a male zebra foal initially showed in vitro resistance to metronidazole (MIC ≥ 256 μg/ml), but lost that trait after subculturing on non-selective media. We conclude that zoo animals belonging to different species can carry ribotype 078 and other toxigenic strains of C. difficile showing resistance to antimicrobial compounds commonly used in veterinary and/or human medicine. Copyright © 2014 Elsevier B.V. All rights reserved.

Archeological Investigations in the Truscott Reservoir Area. King and Knox Counties, Texas,

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1978-06-01

postdate the deposit. Collections consist of an upper molar of Equus sp., two di’stal epiphyses of metapodials of Bison sp., a glenoid fossa of a...includes two lower molars of Equus sp., a fragment of a jaw condyle, and a rib fragment. Since very little material was found at any of these sites, and...Archeological Survey Report No. 6. Austin. 364 McCormick, Olin F. 1976 The Archaic Period in North Central Texas. In The Texas Archaic: A Symposium, edited

Molecular phylogeny of equine herpesvirus 1 isolates from onager, zebra and Thomson's gazelle.

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Ghanem, Y M; Fukushi, H; Ibrahim, E S M; Ohya, K; Yamaguchi, T; Kennedy, M

2008-01-01

Viruses related to equine herpesvirus type 1 (EHV-1) were isolated from an aborted fetus of an onager (Equus hemionus) in 1984, an aborted fetus of Grevy's zebra (Equus grevyi) in 1984 and a Thomson's gazelle (Gazella thomsoni) with nonsuppurative encephalitis in 1996, all in the USA. The mother of the onager fetus and the gazelle were kept near plains zebras (Equus burchelli). In phylogenetic trees based on the nucleotide sequences of the genes for glycoproteins B (gB), I (gI), and E (gE), and teguments including ORF8 (UL51), ORF15 (UL45), and ORF68 (US2), the onager, Grevy's zebra and gazelle isolates formed a genetic group that was different from several horse EHV-1 isolates. Within this group, the onager and gazelle isolates were closely related, while the Grevy's zebra isolate was distantly related to these two isolates. The epizootiological origin of the viruses is discussed.

DNA sequences from the quagga, an extinct member of the horse family.

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Higuchi, R; Bowman, B; Freiberger, M; Ryder, O A; Wilson, A C

To determine whether DNA survives and can be recovered from the remains of extinct creatures, we have examined dried muscle from a museum specimen of the quagga, a zebra-like species (Equus quagga) that became extinct in 1883 (ref. 1). We report that DNA was extracted from this tissue in amounts approaching 1% of that expected from fresh muscle, and that the DNA was of relatively low molecular weight. Among the many clones obtained from the quagga DNA, two containing pieces of mitochondrial DNA (mtDNA) were sequenced. These sequences, comprising 229 nucleotide pairs, differ by 12 base substitutions from the corresponding sequences of mtDNA from a mountain zebra, an extant member of the genus Equus. The number, nature and locations of the substitutions imply that there has been little or no postmortem modification of the quagga DNA sequences, and that the two species had a common ancestor 3-4 Myr ago, consistent with fossil evidence concerning the age of the genus Equus.

Ancient feeding ecology inferred from stable isotopic evidence from fossil horses in South America over the past 3 Ma

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Alberdi María T

2011-06-01

Full Text Available Abstract Background Stable isotope ratios (13C/12C and 18O/16O in fossil teeth and bone provide key archives for understanding the ecology of extinct horses during the Plio-Pleistocene in South America; however, what happened in areas of sympatry between Equus (Amerhippus and Hippidion is less understood. Results Here, we use stable carbon and oxygen isotopes preserved in 67 fossil tooth and bone samples for seven species of horses from 25 different localities to document the magnitude of the dietary shifts of horses and ancient floral change during the Plio-Pleistocene. Dietary reconstructions inferred from stable isotopes of both genera of horses present in South America document dietary separation and environmental changes in ancient ecosystems, including C3/C4 transitions. Stable isotope data demonstrate changes in C4 grass consumption, inter-species dietary partitioning and variation in isotopic niche breadth of mixed feeders with latitudinal gradient. Conclusions The data for Hippidion indicate a preference varying from C3 plants to mixed C3-C4 plants in their diet. Equus (Amerhippus shows three different patterns of dietary partitioning Equus (A. neogeus from the province of Buenos Aires indicate a preference for C3 plants in the diet. Equus (A. andium from Ecuador and Equus (A. insulatus from Bolivia show a preference for to a diet of mixed C3-C4 plants, while Equus (A. santaeelenae from La Carolina (sea level of Ecuador and Brazil are mostly C4 feeders. These results confirm that ancient feeding ecology cannot always be inferred from dental morphology. While the carbon isotope composition of horses skeletal material decreased as latitude increased, we found evidence of boundary between a mixed C3/C4 diet signal and a pure C4 signal around 32° S and a change from a mixed diet signal to an exclusively C3 signal around 35°S. We found that the horses living at high altitudes and at low to middle latitude still have a C4 component in their

Cloning, Phylogenetic Analysis and 3D Modeling of a Putative Lysosomal Acid Lipase from the Camel, Camelus dromedarius

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Farid Shokry Ataya

2012-08-01

Full Text Available Acid lipase belongs to a family of enzymes that is mainly present in lysosomes of different organs and the stomach. It is characterized by its capacity to withstand acidic conditions while maintaining high lipolytic activity. We cloned for the first time the full coding sequence of camel’s lysosomal acid lipase, cLIPA using RT-PCR technique (Genbank accession numbers JF803951 and AEG75815, for the nucleotide and aminoacid sequences respectively. The cDNA sequencing revealed an open reading frame of 1,197 nucleotides that encodes a protein of 399 aminoacids which was similar to that from other related mammalian species. Bioinformatic analysis was used to determine the aminoacid sequence, 3D structure and phylogeny of cLIPA. Bioinformatics analysis suggested the molecular weight of the translated protein to be 45.57 kDa, which could be decreased to 43.16 kDa after the removal of a signal peptide comprising the first 21 aminoacids. The deduced cLIPA sequences exhibited high identity with Equus caballus (86%, Numascus leucogenys (85%, Homo sapiens (84%, Sus scrofa (84%, Bos taurus (82% and Ovis aries (81%. cLIPA shows high aminoacid sequence identity with human and dog-gastric lipases (58%, and 59% respectively which makes it relevant to build a 3D structure model for cLIPA. The comparison confirms the presence of the catalytic triad and the oxyanion hole in cLIPA. Phylogenetic analysis revealed that camel cLIPA is grouped with monkey, human, pig, cow and goat. The level of expression of cLIPA in five camel tissues was examined using Real Time-PCR. The highest level of cLIPA transcript was found in the camel testis (162%, followed by spleen (129%, liver (100%, kidney (20.5% and lung (17.4%.

The albinism of the feral Asinara white donkeys (Equus asinus) is determined by a missense mutation in a highly conserved position of the tyrosinase (TYR) gene deduced protein.

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Utzeri, V J; Bertolini, F; Ribani, A; Schiavo, G; Dall'Olio, S; Fontanesi, L

2016-02-01

A feral donkey population (Equus asinus), living in the Asinara National Park (an island north-west of Sardinia, Italy), includes a unique white albino donkey subpopulation or colour morph that is a major attraction of this park. Disrupting mutations in the tyrosinase (TYR) gene are known to cause recessive albinisms in humans (oculocutaneous albinism Type 1; OCA1) and other species. In this study, we analysed the donkey TYR gene as a strong candidate to identify the causative mutation of the albinism of these donkeys. The TYR gene was sequenced from 13 donkeys (seven Asinara white albino and six coloured animals). Seven single nucleotide polymorphisms were identified. A missense mutation (c.604C>G; p.His202Asp) in a highly conserved amino acid position (even across kingdoms), which disrupts the first copper-binding site (CuA) of functional protein, was identified in the homozygous condition (G/G or D/D) in all Asinara white albino donkeys and in the albino son of a trio (the grey parents had genotype C/G or H/D), supporting the recessive mode of inheritance of this mutation. Genotyping 82 donkeys confirmed that Asinara albino donkeys had genotype G/G whereas all other coloured donkeys had genotype C/C or C/G. Across-population association between the c.604C>G genotypes and the albino coat colour was highly significant (P = 6.17E-18). The identification of the causative mutation of the albinism in the Asinara white donkeys might open new perspectives to study the dynamics of this putative deleterious allele in a feral population and to manage this interesting animal genetic resource. © 2015 Stichting International Foundation for Animal Genetics.

DETOMIDINE AND BUTORPHANOL FOR STANDING SEDATION IN A RANGE OF ZOO-KEPT UNGULATE SPECIES.

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Bouts, Tim; Dodds, Joanne; Berry, Karla; Arif, Abdi; Taylor, Polly; Routh, Andrew; Gasthuys, Frank

2017-09-01

General anesthesia poses risks for larger zoo species, like cardiorespiratory depression, myopathy, and hyperthermia. In ruminants, ruminal bloat and regurgitation of rumen contents with potential aspiration pneumonia are added risks. Thus, the use of sedation to perform minor procedures is justified in zoo animals. A combination of detomidine and butorphanol has been routinely used in domestic animals. This drug combination, administered by remote intramuscular injection, can also be applied for standing sedation in a range of zoo animals, allowing a number of minor procedures. The combination was successfully administered in five species of nondomesticated equids (Przewalski horse [ Equus ferus przewalskii; n = 1], onager [ Equus hemionus onager; n = 4], kiang [ Equus kiang ; n = 3], Grevy's zebra [ Equus grevyi ; n = 4], and Somali wild ass [ Equus africanus somaliensis; n = 7]), with a mean dose range of 0.10-0.17 mg/kg detomidine and 0.07-0.13 mg/kg butorphanol; the white ( Ceratotherium simum simum; n = 12) and greater one-horned rhinoceros ( Rhinoceros unicornis ; n = 4), with a mean dose of 0.015 mg/kg of both detomidine and butorphanol; and Asiatic elephant bulls ( Elephas maximus ; n = 2), with a mean dose of 0.018 mg/kg of both detomidine and butorphanol. In addition, the combination was successfully used for standing sedation in six species of artiodactylids: giraffe ( Giraffa camelopardalis reticulata; n = 3), western bongo ( Tragelaphus eurycerus eurycerus; n = 2), wisent ( Bison bonasus ; n = 5), yak ( Bos grunniens ; n = 1), water buffalo ( Bubalus bubalis ; n = 4) and Bactrian camel ( Camelus bactrianus ; n = 5). The mean dose range for artiodactylid species except bongo was 0.04-0.06 mg/kg detomidine and 0.03-0.06 mg/kg butorphanol. The dose in bongo, 0.15-0.20 mg/kg detomidine and 0.13-0.15 mg/kg butorphanol, was considerably higher. Times to first effect, approach, and recovery after antidote were short. The use of detomidine and butorphanol has

The Role of Science in Managed Aquifer Recharge--the Equus Beds aquifer near Wichita, Kansas Andrew Ziegler, Director Brian Kelly, Office Chief Michael Jacobs, Manager of Water Planning and Production Debra Ary, Engineer, Water Systems Planning (Invited)

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Ziegler, A. C.; Jacobs, M.; Ary, D.; Kelly, B.

2013-12-01

Data collection and interpretation using statistical, geochemical, and numerical simulation tools are essential parts of a long-term cooperative study between the city of Wichita, U.S. Geological Survey, and others to describe water quantity and quality conditions in a 165 square-mile part of the Equus Beds aquifer and Arkansas and Little Arkansas Rivers. The Equus Beds aquifer, eastern part of the High Plains Aquifer in south-central Kansas, is a vital water resource for agriculture and city of Wichita. Withdrawals for public supply began in the 1940s and agricultural irrigation began in the 1950-60s. These withdrawals led to water-level declines of up to 40 feet (historic low in 1993), a storage loss of 250,000 acre feet compared to predevelopment, and may enhance movement of chloride contamination from a past oilfield disposal area near Burrton and from natural chloride along the Arkansas River. Monitoring data and modeling show chloride near Burrton moved about 3 miles in 45 years, is about 1 mile away from the nearest public supply wells, and will continue to move for decades to centuries making the water unusable for irrigation or water supply without treatment. These concerns led to development of Wichita's 1993 integrated local water-supply plan that increased use of Cheney Reservoir and implemented aquifer storage and recovery (ASR) within the aquifer using high flows from the Little Arkansas River. ASR benefits include replacing depleted storage and slowing chloride movement. Decreased withdrawals, increased precipitation, and artificial recharge increased water levels and added 100,000 acre feet of storage through 2010, but drought since 2011 has increased withdrawals. A calibrated model will be used to simulate transport of chloride under several withdrawal scenarios using MODFLOW coupled with SEAWAT. Since 1995, water-quality data collection for more than 400 organic and inorganic compounds in surface water, treated source water for artificial recharge

Equus burchelli antiquorum

African Journals Online (AJOL)

lowed up. This extends the range of Ptenopus into the Great and Little Karroo. Previously the southernmost record as given by Haacke (1975) is from Nuwerust on the west coast. REFERENCES. HAACKE, W. D. 1975. The burrowing geckos of southern Africa, 1 (Reptilia: Gekkonidae). Ann. Transvaal Mus. 29: 197-243. R ep.

equus burchelli antiquorum

African Journals Online (AJOL)

coherent family groups dominated by a single stallion and consist of 2-11 individuals ... determined using an electric balance. ... Observations on E.b. antiquorum indicate that social organization is similar to that observed in ..... supported to some extent by the work of Osterhoff (1966) on biochemical polymorphism in the.

Haematological indices in Trypanosoma brucei brucei (Federe isolate infected Nigerian donkeys (Equus asinus treated with homidium and isometamidium chloride of ciprofloxacin in broiler chickens after single intravenous and intraingluvial administration

Directory of Open Access Journals (Sweden)

Queen Nneka Oparah

2017-03-01

Full Text Available The efficacy of intramuscular administration of Homidium chloride (Novidium® and Isometamidium chloride (Sécuridium® in Nigerian donkeys (Equus asinus experimentally infected with T. b. brucei (Federe isolate was investigated. Changes in haematological and serum biochemical indices were evaluated using clinical haematology and biochemistry methods. Red blood cell (RBC count for the negative control group was significantly higher than for the positive control, Novidium® and Sécuridium®-treatment groups. Haemoglobin (Hb concentration significantly reduced in the infected untreated group compared with other groups. Packed cell volume (PCV was significantly different between negative and positive controls, and also between the infected untreated and treatment groups. There was significant reduction in platelet counts post-infection and post-treatment. Mean corpuscular volume (MCV increased significantly in the treatment groups while mean corpuscular haemoglobin concentration (MCHC significantly reduced only in the Sécuridium®-treatment group. Lymphocyte count for infected untreated was non-significantly higher than for the uninfected controls, but treatment with both trypanocides recorded further increases, which were higher compared with that of the uninfected group. Post infection and treatment, aspartate aminotransferase (AST levels increased significantly. There were non-significant differences in electrolyte ion concentrations across the groups except for chloride ion which recorded a significant reduction in the Novidium®-treatment group. This experiment revealed that Nigerian donkeys infected with T. brucei brucei (Federe isolate developed symptoms of trypanosomosis; anaemia, lymphocytosis and thrombocytopenia. Treatment with the trypanocides ameliorated effects of the infection, and results suggest that immunosuppression may not be a substantial clinical manifestation of T. brucei brucei (Federe isolate trypanosomosis in Nigerian

Aerial population estimates of wild horses (Equus caballus) in the adobe town and salt wells creek herd management areas using an integrated simultaneous double-count and sightability bias correction technique

Science.gov (United States)

Lubow, Bruce C.; Ransom, Jason I.

2007-01-01

An aerial survey technique combining simultaneous double-count and sightability bias correction methodologies was used to estimate the population of wild horses inhabiting Adobe Town and Salt Wells Creek Herd Management Areas, Wyoming. Based on 5 surveys over 4 years, we conclude that the technique produced estimates consistent with the known number of horses removed between surveys and an annual population growth rate of 16.2 percent per year. Therefore, evidence from this series of surveys supports the validity of this survey method. Our results also indicate that the ability of aerial observers to see horse groups is very strongly dependent on skill of the individual observer, size of the horse group, and vegetation cover. It is also more modestly dependent on the ruggedness of the terrain and the position of the sun relative to the observer. We further conclude that censuses, or uncorrected raw counts, are inadequate estimates of population size for this herd. Such uncorrected counts were all undercounts in our trials, and varied in magnitude from year to year and observer to observer. As of April 2007, we estimate that the population of the Adobe Town /Salt Wells Creek complex is 906 horses with a 95 percent confidence interval ranging from 857 to 981 horses.

Infertilidade associada a defeito microtubular dos espermatozóides de jumento (Equus asinus avaliados por microscopia eletrônica de transmissão Infertility associated with microtubular defect in a donkey (Equus asinus spermatozoa evaluated by transmission electron microscopy

Directory of Open Access Journals (Sweden)

André Maciel Crespilho

2006-10-01

Full Text Available Descreve-se um caso de infertilidade de um jumento SRD confirmada por meio de microscopia eletrônica de transmissão (MET. O espermiograma, avaliado sob microscopia ótica, revelou baixa motilidade e alta concentração de anormalidades espermáticas do tipo gota citoplasmática proximal. O material foi avaliado por MET, observando-se um acúmulo desordenado de microtúbulos causando protusões irregulares na região do colo espermático. O último teste realizado correspondeu ao de fertilidade in vivo, utilizando-se quatro éguas portadoras de bom histórico reprodutivo, nas quais não foi possível confirmar nenhuma prenhez. Frente aos resultados obtidos, associados aos achados da MET, estabeleceu-se o diagnóstico de infertilidade associada a defeito microtubular dos espermatozóides.A donkey infertility was described by transmission electron microscopy (MET. The spermiogram evaluated by light microscopy showed low sperm motility and high concentration of abnormal sperm with proximal cytoplasmic droplets. The material was evaluated by MET, where it was observed disarrangement of microtubules, causing irregular protrusions in the spermatic neck. The last test done was the in vivo fertility, using four mares, with a reproductive healthy historic, where no pregnancy occurred. Facing the results that we had in vivo, associated with the MET findings, we diagnosed infertility associated with microtubular defect of the spermatozoa.

Estudio de los caballos del yacimiento de Quibas, Pleistoceno Inferior final (Abanilla, Murcia, España

Directory of Open Access Journals (Sweden)

Piñero, P.

2015-12-01

Full Text Available In this paper, over 60 fossil horse remains from the latest early Pleistocene karstic site of Quibas (Abanilla, Murcia, Spain are described. Their taxonomy and morphology, evolutionary stage, and paleoecological determining factors are studied. The multivariate analysis through comparison with different forms that occur in other Spanish and European localities shows that the majority of the fossils match the medium-sized species Equus altidens. This species represents the last form in the stenonoid lineage. In Spain, E. altidens is related to warm or warm-temperate climate, in woodlands or savanna-mosaic habitats. Equus suessenbornensis is also sparsely represented, first cited in the site of Quibas.En este artículo se describen más de 60 restos fósiles de équido recuperados en el yacimiento kárstico del Pleistoceno Inferior final de Quibas (Abanilla, Murcia. Se hace un estudio de su taxonomía y morfología, estado evolutivo y los factores paleoclimáticos vinculados. Comparando con fósiles de équidos hallados en otras localidades españolas y europeas a través de análisis multivariantes, los restos se asignan en su mayor parte a la especie de tamaño medio Equus altidens, último eslabón del linaje de los caballos estenonianos. En España, esta especie se relaciona con unas condiciones climáticas cálidas o cálidas-templadas, cuya vegetación principal estaría compuesta de bosque o bosque-sabana. Se constata también una escasa presencia de Equus suessenbornensis por primera vez en el yacimiento de Quibas.

Ancient DNA from Nubian and Somali wild ass provides insights into donkey ancestry and domestication.

Science.gov (United States)

Kimura, Birgitta; Marshall, Fiona B; Chen, Shanyuan; Rosenbom, Sónia; Moehlman, Patricia D; Tuross, Noreen; Sabin, Richard C; Peters, Joris; Barich, Barbara; Yohannes, Hagos; Kebede, Fanuel; Teclai, Redae; Beja-Pereira, Albano; Mulligan, Connie J

2011-01-07

Genetic data from extant donkeys (Equus asinus) have revealed two distinct mitochondrial DNA haplogroups, suggestive of two separate domestication events in northeast Africa about 5000 years ago. Without distinct phylogeographic structure in domestic donkey haplogroups and with little information on the genetic makeup of the ancestral African wild ass, however, it has been difficult to identify wild ancestors and geographical origins for the domestic mitochondrial clades. Our analysis of ancient archaeological and historic museum samples provides the first genetic information on the historic Nubian wild ass (Equus africanus africanus), Somali wild ass (Equus africanus somaliensis) and ancient donkey. The results demonstrate that the Nubian wild ass was an ancestor of the first donkey haplogroup. In contrast, the Somali wild ass has considerable mitochondrial divergence from the Nubian wild ass and domestic donkeys. These findings resolve the long-standing issue of the role of the Nubian wild ass in the domestication of the donkey, but raise new questions regarding the second ancestor for the donkey. Our results illustrate the complexity of animal domestication, and have conservation implications for critically endangered Nubian and Somali wild ass.

The evolution and anatomy of the horse manus with an emphasis on digit reduction

Science.gov (United States)

Danowitz, Melinda; Stachtiaris, Elizabeth; Khurana, Abhilasha; Araim, Marwan; Sayegh, Marc; Natale, Jessica

2018-01-01

We revisit digit reduction in the horse and propose that all five digits are partially present in the modern adult forelimb. Osteological descriptions of selected tetradactyl, tridactyl and monodactyl equids demonstrate the evolution of the forelimb. Histological, osteological and palaeontological evidence suggest that the Equus distal forelimb is more complex than traditionally conceived. The current understanding is that the horse distal forelimb consists of one complete digit (III) and two reduced splint metacarpals (II and IV). Metacarpals II and IV each exhibit a ventral ridge, which we suggest represents the undifferentiated digits I and V. These ridges are present in the tridactyl Mesohippus, but are absent in the tetradactyl Hyracotherium. The carpal articulations of the five metacarpals match those of pentadactyl taxa. Distally, the frog, a V-shaped structure on the ventral hoof represents digits II and IV, and the wings and hoof cartilages of the distal phalanx are digits I and V. We relate this revised interpretation of the Equus forelimb to Laetoli footprints, and suggest the Hipparion side impressions are created from the hooves of I and V, rather than from II and IV. We show shades of pentadactyly within the Equus manus. PMID:29410871

Analysis of horse genomes provides insight into the diversification and adaptive evolution of karyotype.

Science.gov (United States)

Huang, Jinlong; Zhao, Yiping; Shiraigol, Wunierfu; Li, Bei; Bai, Dongyi; Ye, Weixing; Daidiikhuu, Dorjsuren; Yang, Lihua; Jin, Burenqiqige; Zhao, Qinan; Gao, Yahan; Wu, Jing; Bao, Wuyundalai; Li, Anaer; Zhang, Yuhong; Han, Haige; Bai, Haitang; Bao, Yanqing; Zhao, Lele; Zhai, Zhengxiao; Zhao, Wenjing; Sun, Zikui; Zhang, Yan; Meng, He; Dugarjaviin, Manglai

2014-05-14

Karyotypic diversification is more prominent in Equus species than in other mammals. Here, using next generation sequencing technology, we generated and de novo assembled quality genomes sequences for a male wild horse (Przewalski's horse) and a male domestic horse (Mongolian horse), with about 93-fold and 91-fold coverage, respectively. Portion of Y chromosome from wild horse assemblies (3 M bp) and Mongolian horse (2 M bp) were also sequenced and de novo assembled. We confirmed a Robertsonian translocation event through the wild horse's chromosomes 23 and 24, which contained sequences that were highly homologous with those on the domestic horse's chromosome 5. The four main types of rearrangement, insertion of unknown origin, inserted duplication, inversion, and relocation, are not evenly distributed on all the chromosomes, and some chromosomes, such as the X chromosome, contain more rearrangements than others, and the number of inversions is far less than the number of insertions and relocations in the horse genome. Furthermore, we discovered the percentages of LINE_L1 and LTR_ERV1 are significantly increased in rearrangement regions. The analysis results of the two representative Equus species genomes improved our knowledge of Equus chromosome rearrangement and karyotype evolution.

Sennar Jacks (Equus asinus)

African Journals Online (AJOL)

This study was carried out with an objective of evaluating the breeding soundness and sexual behavior of Sennar jackasses. ... score of 7 for the breeding and 4.8 for the working jacks. The mean (iSE) of height at wither,the ..... Equine Reproductive Physiology, Breeding and Stud Manage- ment, 2ndEdn. Farming Press ...

Detection probability in aerial surveys of feral horses

Science.gov (United States)

Ransom, Jason I.

2011-01-01

Observation bias pervades data collected during aerial surveys of large animals, and although some sources can be mitigated with informed planning, others must be addressed using valid sampling techniques that carefully model detection probability. Nonetheless, aerial surveys are frequently employed to count large mammals without applying such methods to account for heterogeneity in visibility of animal groups on the landscape. This often leaves managers and interest groups at odds over decisions that are not adequately informed. I analyzed detection of feral horse (Equus caballus) groups by dual independent observers from 24 fixed-wing and 16 helicopter flights using mixed-effect logistic regression models to investigate potential sources of observation bias. I accounted for observer skill, population location, and aircraft type in the model structure and analyzed the effects of group size, sun effect (position related to observer), vegetation type, topography, cloud cover, percent snow cover, and observer fatigue on detection of horse groups. The most important model-averaged effects for both fixed-wing and helicopter surveys included group size (fixed-wing: odds ratio = 0.891, 95% CI = 0.850–0.935; helicopter: odds ratio = 0.640, 95% CI = 0.587–0.698) and sun effect (fixed-wing: odds ratio = 0.632, 95% CI = 0.350–1.141; helicopter: odds ratio = 0.194, 95% CI = 0.080–0.470). Observer fatigue was also an important effect in the best model for helicopter surveys, with detection probability declining after 3 hr of survey time (odds ratio = 0.278, 95% CI = 0.144–0.537). Biases arising from sun effect and observer fatigue can be mitigated by pre-flight survey design. Other sources of bias, such as those arising from group size, topography, and vegetation can only be addressed by employing valid sampling techniques such as double sampling, mark–resight (batch-marked animals), mark–recapture (uniquely marked and

Inorganic elements determination in human and animal whole blood samples by X-ray fluorescence technique (EDXRF)

International Nuclear Information System (INIS)

Redigolo, Marcelo Miyada

2011-01-01

Blood is a suspension of cells contained in a complex liquid called plasma. The term 'whole blood' refers to samples with both solid and liquid parts. Inorganic elements are responsible for essential functions, such as osmotic regulation, cardiac frequency and contractibility, blood clotting and neuromuscular excitability. The determination of inorganic elements in corporeal fluids such as blood, serum, plasma, tissue and urine is used as a monitor for a part or the whole organism. In this work, the X-Ray fluorescence technique (EDXRF) was used for the determination of inorganic elements in whole blood samples from humans and animals (golden hamsters, Mesocricetus auratus and crioula breed horses, Equus caballus). The reference intervals of Na (1788 - 1826 μg g'- 1 ), Mg (63 - 75 μg g -1 ), P (602 - 676 μg g -1 ), S (1519 - 1718 μg g -1 ), Cl (2743 - 2867 μg g -1 ), K (1508 - 1630 μg g -1 ), Ca (214 - 228 μg g'- 1 ), Cu (4 -6 μg g -1 ) e Zn (1 - 3 μg g'- 1 ) were determined for human blood. The reference intervals, for golden hamster blood were found to be: Na (1714 - 1819 μg g -1 ), Mg (51 - 79 μg g -1 ), P (970 - 1080 μg g -1 ), S (1231 - 1739 μg g -1 ), Cl (2775 - 2865 μg g -1 ), K (1968 - 2248 μg g -1 ), Ca (209 - 257 μg g-1), Cu (4 - 6 μg g -1 ) e Zn (3 - 5 μg g -1 ). The reference intervals, for crioula breed horse blood, showed to be: Na (1955 - 2013 μg g -1 ), Mg (51 - 75 μg g -1 ), P (443 - 476 μg g -1 ), S (1038 - 1140 μg g - '1), Cl (2388 - 2574 μg g -1 ), K (1678 - 1753 μg g -1 ), Ca (202 - 213 μg g -1 ), Cu (4,1 - 4,5 μg g -1 ) e Zn (2,0 - 2,2 μg g -1 ). Comparative study between NAA and EDXRF, both techniques showed the same performance for the analyses of biological matrices. The results contribute for the establishment of reference intervals for the Brazilian healthy population and the referred animal species. (author)

Equine infectious anemia prevalence in feral donkeys from Northeast Brazil.

Science.gov (United States)

Oliveira, Fernanda G; Cook, R Frank; Naves, João H F; Oliveira, Cairo H S; Diniz, Rejane S; Freitas, Francisco J C; Lima, Joseney M; Sakamoto, Sidnei M; Leite, Rômulo C; Issel, Charles J; Reis, Jenner K P

2017-05-01

Equine infectious anemia virus (EIAV) is an important cause of morbidity and mortality throughout the world. Although the virus infects all members of the Equidae the vast majority of studies have been conducted in horses (Equus caballus) with comparatively little information available for other equid species. Brazil has one of the most abundant donkey (E. asinus) populations of any nation although the economic importance of these animals is declining as transportation becomes increasingly mechanized. As a result, considerable numbers of donkeys especially in the Northeast of the country have been released and allowed pursue an almost feral existence. Consequently, this large and growing population constitutes a significant risk as a reservoir for the maintenance and transmission of important equine infectious diseases such as glanders and equine arteritis virus in addition to EIAV. This study examines the prevalence of EIA in a semi-wild donkey population from Mossoró city, in Northeast Brazil, using AGID followed by cELISA, rgp90 ELISA and immunoblot (IB). Serum samples were collected from 367 donkeys without obvious EIA clinical signs. Subsequent testing revealed seropositive rates of 1.6% (6/367) in officially approved AGID tests, 3.3% (12/367) in cELISA and 14.4% (53/367) in the rgp90 ELISA. However, 88.7% (47/53) of the rgp90 ELISA positive samples were almost certainly false reactions because they failed to react with two or more antigens in IB. Consequently, the rpg90 ELISA has a similar sensitivity to AGID with donkey serum samples. Such high false positive rates have not been observed previously with serum samples from horses. Another highly significant finding is that 56.9% (33/58) of the donkey serum samples tested in IB had reactivity to EIAV p26 only. Although this could result from recent infection with the virus, it has been found that in some equids p26 only reactivity persists for extensive periods of time suggesting exposure to antigens

Effect of feeding glucose, fructose, and inulin on blood glucose and insulin concentrations in normal ponies and those predisposed to laminitis.

Science.gov (United States)

Borer, K E; Bailey, S R; Menzies-Gow, N J; Harris, P A; Elliott, J

2012-09-01

Identification of ponies (Equus caballus) at increased risk of pasture-associated laminitis would aid in the prevention of the disease. Insulin resistance has been associated with laminitis and could be used to identify susceptible individuals. Insulin resistance may be diagnosed by feeding supplementary water-soluble carbohydrate (WSC) and measuring blood glucose and insulin concentrations. The aim of this study was to assess the glycemic and insulinemic responses of 7 normal (NP) and 5 previously laminitic (PLP), mixed breed, native UK ponies fed glucose, fructose, and inulin [1 g/(kg·d) for 3 d] or no supplementary WSC (control) in spring and fall after a 7-d adaptation to a pasture or hay diet. Blood samples were taken for 12 h after feeding on each day, and baseline and peak concentrations and area under the curve (AUC) for glucose and insulin were recorded. Linear mixed models were used for statistical analysis. Differences between PLP and NP groups were most marked after glucose feeding with differences in peak glucose (P = 0.02) and peak insulin (P = 0.016) concentrations. Season and diet adaptation also affected results. Peak concentrations of glucose and insulin occurred 2 to 4 h after WSC feeding. Peak insulin concentration was greater and more variable in fall, particularly in PLP adapted to fall pasture. Baseline glucose and insulin concentrations varied between individuals and with season and diet adaptation but were not greater in PLP than NP. Insulin AUC was greater in PLP than NP after feeding both glucose and fructose (P = 0.017), but there were no differences between PLP and NP in glucose AUC. Glycemic and insulinemic changes were less (P ≤ 0.05) after feeding fructose than glucose, although differences between PLP and NP were still evident. Minimal changes in glucose and insulin concentrations occurred after inulin feeding. Measurement of peak insulin 2 h after feeding of a single dose of glucose (1 g/kg) may be a simple and practical way to

Feeding niches of four large herbivores in the Hluhluwe Game ...

African Journals Online (AJOL)

Feeding niches of four large herbivores in the Hluhluwe Game Reserve, Natal. ... equus burchelli burchelli; feeding; grass; grasses; habitat; herbivores; hluhluwe game reserve; kwazulu-natal; large herbivores; ... AJOL African Journals Online.

Mitochondrial phylogenomics of modern and ancient equids.

Science.gov (United States)

Vilstrup, Julia T; Seguin-Orlando, Andaine; Stiller, Mathias; Ginolhac, Aurelien; Raghavan, Maanasa; Nielsen, Sandra C A; Weinstock, Jacobo; Froese, Duane; Vasiliev, Sergei K; Ovodov, Nikolai D; Clary, Joel; Helgen, Kristofer M; Fleischer, Robert C; Cooper, Alan; Shapiro, Beth; Orlando, Ludovic

2013-01-01

The genus Equus is richly represented in the fossil record, yet our understanding of taxonomic relationships within this genus remains limited. To estimate the phylogenetic relationships among modern horses, zebras, asses and donkeys, we generated the first data set including complete mitochondrial sequences from all seven extant lineages within the genus Equus. Bayesian and Maximum Likelihood phylogenetic inference confirms that zebras are monophyletic within the genus, and the Plains and Grevy's zebras form a well-supported monophyletic group. Using ancient DNA techniques, we further characterize the complete mitochondrial genomes of three extinct equid lineages (the New World stilt-legged horses, NWSLH; the subgenus Sussemionus; and the Quagga, Equus quagga quagga). Comparisons with extant taxa confirm the NWSLH as being part of the caballines, and the Quagga and Plains zebras as being conspecific. However, the evolutionary relationships among the non-caballine lineages, including the now-extinct subgenus Sussemionus, remain unresolved, most likely due to extremely rapid radiation within this group. The closest living outgroups (rhinos and tapirs) were found to be too phylogenetically distant to calibrate reliable molecular clocks. Additional mitochondrial genome sequence data, including radiocarbon dated ancient equids, will be required before revisiting the exact timing of the lineage radiation leading up to modern equids, which for now were found to have possibly shared a common ancestor as far as up to 4 Million years ago (Mya).

Mitochondrial Phylogenomics of Modern and Ancient Equids

Science.gov (United States)

Vilstrup, Julia T.; Seguin-Orlando, Andaine; Stiller, Mathias; Ginolhac, Aurelien; Raghavan, Maanasa; Nielsen, Sandra C. A.; Weinstock, Jacobo; Froese, Duane; Vasiliev, Sergei K.; Ovodov, Nikolai D.; Clary, Joel; Helgen, Kristofer M.; Fleischer, Robert C.; Cooper, Alan; Shapiro, Beth; Orlando, Ludovic

2013-01-01

The genus Equus is richly represented in the fossil record, yet our understanding of taxonomic relationships within this genus remains limited. To estimate the phylogenetic relationships among modern horses, zebras, asses and donkeys, we generated the first data set including complete mitochondrial sequences from all seven extant lineages within the genus Equus. Bayesian and Maximum Likelihood phylogenetic inference confirms that zebras are monophyletic within the genus, and the Plains and Grevy’s zebras form a well-supported monophyletic group. Using ancient DNA techniques, we further characterize the complete mitochondrial genomes of three extinct equid lineages (the New World stilt-legged horses, NWSLH; the subgenus Sussemionus; and the Quagga, Equus quagga quagga). Comparisons with extant taxa confirm the NWSLH as being part of the caballines, and the Quagga and Plains zebras as being conspecific. However, the evolutionary relationships among the non-caballine lineages, including the now-extinct subgenus Sussemionus, remain unresolved, most likely due to extremely rapid radiation within this group. The closest living outgroups (rhinos and tapirs) were found to be too phylogenetically distant to calibrate reliable molecular clocks. Additional mitochondrial genome sequence data, including radiocarbon dated ancient equids, will be required before revisiting the exact timing of the lineage radiation leading up to modern equids, which for now were found to have possibly shared a common ancestor as far as up to 4 Million years ago (Mya). PMID:23437078

Mitochondrial phylogenomics of modern and ancient equids.

Directory of Open Access Journals (Sweden)

Julia T Vilstrup

Full Text Available The genus Equus is richly represented in the fossil record, yet our understanding of taxonomic relationships within this genus remains limited. To estimate the phylogenetic relationships among modern horses, zebras, asses and donkeys, we generated the first data set including complete mitochondrial sequences from all seven extant lineages within the genus Equus. Bayesian and Maximum Likelihood phylogenetic inference confirms that zebras are monophyletic within the genus, and the Plains and Grevy's zebras form a well-supported monophyletic group. Using ancient DNA techniques, we further characterize the complete mitochondrial genomes of three extinct equid lineages (the New World stilt-legged horses, NWSLH; the subgenus Sussemionus; and the Quagga, Equus quagga quagga. Comparisons with extant taxa confirm the NWSLH as being part of the caballines, and the Quagga and Plains zebras as being conspecific. However, the evolutionary relationships among the non-caballine lineages, including the now-extinct subgenus Sussemionus, remain unresolved, most likely due to extremely rapid radiation within this group. The closest living outgroups (rhinos and tapirs were found to be too phylogenetically distant to calibrate reliable molecular clocks. Additional mitochondrial genome sequence data, including radiocarbon dated ancient equids, will be required before revisiting the exact timing of the lineage radiation leading up to modern equids, which for now were found to have possibly shared a common ancestor as far as up to 4 Million years ago (Mya.

Zvířecí kosti ze středobronzové jámy ze Slaného (okr. Kladno)

Czech Academy of Sciences Publication Activity Database

Kyselý, René

2012-01-01

Roč. 2012, č. 3 (2012), s. 118-119 ISSN 1804-2953 Institutional research plan: CEZ:AV0Z80020508 Keywords : archaeozoology * osteology * Bronze Age * horse (Equus) Subject RIV: AC - Archeology, Anthropology, Ethnology

Electron/electron acoustic instability

International Nuclear Information System (INIS)

Gary, S.P.

1987-01-01

The electron acoustic wave becomes a normal mode of an unmagnetized collisionless plasma in the presence of two electron components with similar densities, but strongly disparate temperatures. The characteristic frequency of this mode is the plasma frequency of the cooler electron component. If these two electron components have a relative drift speed several times the thermal speed of the cooler component, the electron/electron acoustic instability may arise. This paper describes the parametric dependences of the threshold drift speed and maximum growth rate of this instability, and compares these with the same properties of the electron/ion acoustic instability. Under the condition of zero current, the electron/ion acoustic instability typically has the lower threshold drift speed, so that observation of the electron/electron acoustic instability is a strong indication of the presence of an electrical current in the plasma

Ecological Monitoring and Compliance Program 2006 Report

Energy Technology Data Exchange (ETDEWEB)

David C. Anderson; Paul D. Greger; Derek B. Hall; Dennis J. Hansen; William K. Ostler

2007-03-01

The Ecological Monitoring and Compliance program (EMAC), funded through the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO), monitors the ecosystem of the Nevada Test Site (NTS) and ensures compliance with laws and regulations pertaining to NTS biota. This report summarizes the program's activities conducted by National Security Technologies LLC (NSTec) during the Calendar Year 2006. Program activities included: (a) biological surveys at proposed construction sites, (b) desert tortoise compliance, (c) ecosystem mapping and data management, (d) sensitive plant species monitoring, (e) sensitive and protected/regulated animal monitoring, (f) habitat monitoring, (g) habitat restoration monitoring, and (h) monitoring of the Nonproliferation Test and Evaluation Complex (NPTEC). Sensitive and protected/regulated species of the NTS include 44 plants, 1 mollusk, 2 reptiles, over 250 birds, and 26 mammals protected, managed, or considered sensitive as per state or federal regulations and natural resource agencies and organizations. The threatened desert tortoise (Gopherus agassizii) is the only species on the NTS protected under the Endangered Species Act. Biological surveys for the presence of sensitive and protected/regulated species and important biological resources on which they depend were conducted for 34 projects. A total of 342.1 hectares (ha) (845.37 acres [ac]) was surveyed for these projects. Sensitive and protected/regulated species and important biological resources found included: 2 inactive tortoise burrows, 2 western burrowing owls (Athene cunicularia hypugaea), several horses (Equus caballus), 2 active predator burrows, mature Joshua trees (Yucca brevifolia), yuccas and cacti; and also 1 bird nest (2 eggs), 1 barn owl (Tyto alba) and 2 great-horned owls (Bubo virginianus). NSTec provided a written summary report of all survey findings and mitigation recommendations, where applicable. All flagged burrows

Electronics and electronic systems

CERN Document Server

Olsen, George H

1987-01-01

Electronics and Electronic Systems explores the significant developments in the field of electronics and electronic devices. This book is organized into three parts encompassing 11 chapters that discuss the fundamental circuit theory and the principles of analog and digital electronics. This book deals first with the passive components of electronic systems, such as resistors, capacitors, and inductors. These topics are followed by a discussion on the analysis of electronic circuits, which involves three ways, namely, the actual circuit, graphical techniques, and rule of thumb. The remaining p

Electrons, Electronic Publishing, and Electronic Display.

Science.gov (United States)

Brownrigg, Edwin B.; Lynch, Clifford A.

1985-01-01

Provides a perspective on electronic publishing by distinguishing between "Newtonian" publishing and "quantum-mechanical" publishing. Highlights include media and publishing, works delivered through electronic media, electronic publishing and the printed word, management of intellectual property, and recent copyright-law issues…

Electron-electron Bremsstrahlung for bound target electrons

International Nuclear Information System (INIS)

Haug, E.

2008-01-01

For the process of electron-electron (e-e) Bremsstrahlung the momentum and energy distributions of the recoiling electrons are calculated in the laboratory frame. In order to get the differential cross section and the photon spectrum for target electrons which are bound to an atom, these formulae are multiplied by the incoherent scattering function and numerically integrated over the recoil energy. The effect of atomic binding is most pronounced at low energies of the incident electrons and for target atoms of high atomic numbers. The results are compared to those of previous calculations. (authors)

Dining in the Pleistocene—Who's on the menu?

Science.gov (United States)

Kohn, Matthew J.; McKay, Moriah P.; Knight, James L.

2005-08-01

The Camelot local fauna, a new fossil locality in southeastern South Carolina, has yielded a spectacularly abundant and well-preserved late Irvingtonian (ca. 400 ka) megafauna, including saber-toothed cat (Smilodon fatalis), wolf (Canis armbrusteri), cheetah (Miracinonyx inexpectatus), “camels” (Hemiauchenia macrocephala and Paleolama mirifica), tapir (Tapirus veroensis), deer (Odocoileus virginianus), sloth (Megalonyx jeffersoni), and horse (Equus sp.). Of particular interest is the number of well-preserved fossil teeth and the ability to decipher paleoecologies and paleodiets, especially for carnivores, by using carbon isotope compositions (δ13C) of these teeth. P. mirifica, M. jeffersoni, O. virginianus, and T. veroensis have the lowest δ13C values (-16‰ to -13‰, Vienna Peedee belemnite standard); C. armbrusteri, S. fatalis, and H. macrocephala have intermediate values (-13‰ to -8‰); and Equus sp. has the highest values (-7‰ to -1‰). High (>-5‰) vs. low (≤-9‰) δ13C values for herbivores indicate local habitats dominated by warm-climate grasses vs. trees and shrubs. The high δ13C values for Equus sp. indicate the presence of grasslands, whereas the low δ13C values for the other herbivores generally indicate the presence of forests. Although few data are available for carnivores, moderate δ13C values for C. armbrusteri indicate that it preyed mainly upon forest herbivores. S. fatalis appears to have preferred marginal woodland-grassland areas.

Interplay between electron-phonon and electron-electron interactions

International Nuclear Information System (INIS)

Roesch, O.; Gunnarsson, O.; Han, J.E.; Crespi, V.H.

2005-01-01

We discuss the interplay between electron-electron and electron-phonon interactions for alkali-doped fullerides and high temperature superconductors. Due to the similarity of the electron and phonon energy scales, retardation effects are small for fullerides. This raises questions about the origin of superconductivity, since retardation effects are believed to be crucial for reducing effects of the Coulomb repulsion in conventional superconductors. We demonstrate that by treating the electron-electron and electron-phonon interactions on an equal footing, superconductivity can be understood in terms of a local pairing. The Jahn-Teller character of the important phonons in fullerides plays a crucial role for this result. To describe effects of phonons in cuprates, we derive a t-J model with phonons from the three-band model. Using exact diagonalization for small clusters, we find that the anomalous softening of the half-breathing phonon as well as its doping dependence can be explained. By comparing the solution of the t-J model with the Hartree-Fock approximation for the three-band model, we address results obtained in the local-density approximation for cuprates. We find that genuine many-body results, due to the interplay between the electron-electron and electron-phonon interactions, play an important role for the the results in the t-J model. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

A rapid loss of stripes: the evolutionary history of the extinct quagga.

Science.gov (United States)

Leonard, Jennifer A; Rohland, Nadin; Glaberman, Scott; Fleischer, Robert C; Caccone, Adalgisa; Hofreiter, Michael

2005-09-22

Twenty years ago, the field of ancient DNA was launched with the publication of two short mitochondrial (mt) DNA sequences from a single quagga (Equus quagga) museum skin, an extinct South African equid (Higuchi et al. 1984 Nature312, 282-284). This was the first extinct species from which genetic information was retrieved. The DNA sequences of the quagga showed that it was more closely related to zebras than to horses. However, quagga evolutionary history is far from clear. We have isolated DNA from eight quaggas and a plains zebra (subspecies or phenotype Equus burchelli burchelli). We show that the quagga displayed little genetic diversity and very recently diverged from the plains zebra, probably during the penultimate glacial maximum. This emphasizes the importance of Pleistocene climate changes for phylogeographic patterns in African as well as Holarctic fauna.

A southern African origin and cryptic structure in the highly mobile plains zebra

DEFF Research Database (Denmark)

Pedersen, Casper-Emil T; Albrechtsen, Anders; Etter, Paul D.

2018-01-01

insights into the past phylogeography of the species. The results identify a southern African location as the most likely source region from which all extant populations expanded around 370,000 years ago. We show evidence for inclusion of the extinct and phenotypically divergent quagga (Equus quagga quagga......The plains zebra (Equus quagga) is an ecologically important species of the African savannah. It is also one of the most numerous and widely distributed ungulates, and six subspecies have been described based on morphological variation. However, the within-species evolutionary processes have been...... difficult to resolve due to its high mobility and a lack of consensus regarding the population structure. We obtained genome-wide DNA polymorphism data from more than 167,000 loci for 59 plains zebras from across the species range, encompassing all recognized extant subspecies, as well as three mountain...

Teismeliste üksindus ja kommerts - teema nii Londonis kui ka meil / Tõnis Mägi

Index Scriptorium Estoniae

Mägi, Tõnis, 1948-

2007-01-01

Muusik räägib, mida huvitavat ta nägi Londonis. Lähemalt Peter Shafferi näidendi "Equus" lavastusest, peaosades Richard Griffith ja Daniel Radcliffe. Artikkel ilmub Teatrikülgedel rubriigis "Teater & küljed" 5/17

Forage patch use by grazing herbivores in a South African grazing ecosystem

NARCIS (Netherlands)

Venter, J.A.; Nabe-Nielsen, J.; Prins, H.H.T.; Slotow, R.

2014-01-01

Understanding how different herbivores make forage patch use choices explains how they maintain an adequate nutritional status, which is important for effective conservation management of grazing ecosystems. Using telemetry data, we investigated nonruminant zebra (Equus burchelli) and ruminant red

Anaerobic respiratory growth of Vibrio harveyi, Vibrio fischeri and Photobacterium leiognathi with trimethylamine N-oxide, nitrate and fumarate: ecological implications.

Science.gov (United States)

Proctor, L M; Gunsalus, R P

2000-08-01

Two symbiotic species, Photobacterium leiognathi and Vibrio fischeri, and one non-symbiotic species, Vibrio harveyi, of the Vibrionaceae were tested for their ability to grow by anaerobic respiration on various electron acceptors, including trimethylamine N-oxide (TMAO) and dimethylsulphoxide (DMSO), compounds common in the marine environment. Each species was able to grow anaerobically with TMAO, nitrate or fumarate, but not with DMSO, as an electron acceptor. Cell growth under microaerophilic growth conditions resulted in elevated levels of TMAO reductase, nitrate reductase and fumarate reductase activity in each strain, whereas growth in the presence of the respective substrate for each enzyme further elevated enzyme activity. TMAO reductase specific activity was the highest of all the reductases. Interestingly, the bacteria-colonized light organs from the two squids, Euprymna scolopes and Euprymna morsei, and the light organ of the ponyfish, Leiognathus equus, also had high levels of TMAO reductase enzyme activity, in contrast to non-symbiotic tissues. The ability of these bacterial symbionts to support cell growth by respiration with TMAO may conceivably eliminate the competition for oxygen needed for both bioluminescence and metabolism.

Resource partitioning between large herbivores in Hustai National Park, Mongolia

NARCIS (Netherlands)

Sietses, D.J.; Faupin, G.; Boer, de W.F.; Jong, de C.B.; Henkens, R.J.H.G.; Usukhjargal, D.; Batbaatar, T.

2009-01-01

Re-introduced Przewalski horses in Hustai National Park, Mongolia could suffer from food competition with other herbivore species through food resource depletion. Diet composition of the Przewalski horse (Equus ferus przewalskii), red deer (Cervus elaphus) and four livestock species (sheep, goat,

Electronic emission and electron guns

International Nuclear Information System (INIS)

Roy, Amitava

2010-01-01

This paper reviews the process of electron emission from metal surface. Although electrons move freely in conductors like metals, they normally do not leave the metal without some manipulation. In fact, heating and bombardment are the two primary ways in which electrons are emitted through the use of a heating element behind the cathode (termed thermionic emission) or as a result of bombardment with a beam of electrons, ions, or metastable atoms (termed secondary emission). Another important emission mechanism called Explosive Electron Emission (EEE) is also often used in various High Voltage Pulse Power Systems to generate very high current (few hundreds of kA) pulsed electron beams. The electron gun is the device in that it shoots off a continuous (or pulsed) stream of electrons. A brief idea about the evolution of the electron gun components and their basis of functioning are also discussed. (author)

Journal of Genetics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Genetics; Volume 96; Online resources. Low genetic diversity of the endangered Indian wild ass Equus hemionus khur, as revealed by microsatellite analyses. DEVENDRA KHAIRE ASHWIN ATKULWAR SAMEERA FARAH MUMTAZ BAIG. Online Resource Volume 96 Online resources 2017 pp ...

Mitochondrial phylogenomics of modern and ancient equids

DEFF Research Database (Denmark)

Mouatt, Julia Thidamarth Vilstrup; Seguin-Orlando, Andaine; Stiller, Mathias

2013-01-01

The genus Equus is richly represented in the fossil record, yet our understanding of taxonomic relationships within this genus remains limited. To estimate the phylogenetic relationships among modern horses, zebras, asses and donkeys, we generated the first data set including complete mitochondrial...

Genetic evaluation of the captive breeding program of the Persian wild ass

DEFF Research Database (Denmark)

Nielsen, R.K.; Pertoldi, C.; Loeschcke, Volker

2007-01-01

the interpretation of the results obtained from analyses based on such data. In this investigation, 12 microsatellite loci were investigated to evaluate the studbook information of the critically endangered Persian wild ass, Equus hemionus onager. Relatedness and inbreeding coefficients were calculated in order...

Wolf Predation Among Reintroduced Przewalski Horses in Hustai National Park, Mongolia

NARCIS (Netherlands)

Duyne, van C.; Ras, E.; Vos, de A.E.W.; Boer, de W.F.; Henkens, R.J.H.G.; Usukhjargal, D.

2009-01-01

Depredation by wolves (Canis lupus) could threaten survival of reintroduced wild Przewalski horses (Equus ferus przewalskii) in Hustai National Park (HNP), Mongolia. We conducted scat analysis, spatial analyses of kills, and interviews to study prey species selection and temporal and spatial factors

Sobre la identidad del fragmento craneal atribuido a Homo sp. en Venta Mlcena (Orce Granada

Directory of Open Access Journals (Sweden)

Moyá-Solá, S.

1987-12-01

Full Text Available The internal morphology of the cranial fragment attributed to Homo from Venta Micena (Granada is analysed. The presence of a coronal suture close to lambda does not permit its attribution to the genus Homo. The distace between the coronal suture and lambda (4 cm., the presence of tentorial procces and the digital impresions strongly suggesst its attribution to a juvenil specimen of Equus stenonis.Se analiza la morfología de la cara interna del fragmento craneal de Venta Micena atribuido inicialmente al género Homo. Se detecta la presencia de la sutura coronal a cuatro centímetros del punto lambda. Ello, conjuntamente a las fuertes impresiones digitales del endocraneo y la presencia de una cresta del proceso oseo tentoríal hacen imposible la adscripción de esta pieza al género Homo., atribuyendose a Equus stenonis.

Gasterophilus (Diptera, Gasterophilidae infestation of equids in the Kalamaili Nature Reserve, China

Directory of Open Access Journals (Sweden)

Huang Heqing

2016-01-01

Full Text Available We investigated infections with Gasterophilus spp. in three equids within the Kalamaili Nature Reserve (northern China. We conducted necropsies on 6 Przewalski’s horses (Equus ferus przewalskii and 6 Mongolian wild asses (Equus hemionus and administered ivermectin to 10 overwintering domestic horses to expel parasites during winter periods. All 22 equids studied (100% were infested with Gasterophilus spp. and a total of 17,225 larvae were collected. These included six species: G. haemorrhoidalis, G. inermis, G. intestinalis, G. nasalis, G. nigricornis, and G. pecorum. The mean intensity of Gasterophilus spp. larvae was 1904 in Przewalski’s horses, 780 in Mongolian wild asses, and 113 in domestic horses. Gasterophilus pecorum was the most abundant species in all three equids. Przewalski’s horses, a reintroduced species, had a significantly higher intensity of Gasterophilus spp. than the Mongolian wild ass, indicating greater susceptibility to parasites in its ancestral home.

Born-Oppenheimer Dynamics, Electronic Friction, and the Inclusion of Electron-Electron Interactions

Science.gov (United States)

Dou, Wenjie; Miao, Gaohan; Subotnik, Joseph E.

2017-07-01

We present a universal expression for the electronic friction as felt by a set of classical nuclear degrees of freedom (DOFs) coupled to a manifold of quantum electronic DOFs; no assumptions are made regarding the nature of the electronic Hamiltonian and electron-electron repulsions are allowed. Our derivation is based on a quantum-classical Liouville equation for the coupled electronic-nuclear motion, followed by an adiabatic approximation whereby electronic transitions are assumed to equilibrate faster than nuclear movement. The resulting form of friction is completely general, but does reduce to previously published expressions for the quadratic Hamiltonian (i.e., Hamiltonians without electronic correlation). At equilibrium, the second fluctuation-dissipation theorem is satisfied and the frictional matrix is symmetric. To demonstrate the importance of electron-electron correlation, we study electronic friction within the Anderson-Holstein model, where a proper treatment of electron-electron interactions shows signatures of a Kondo resonance and a mean-field treatment is completely inadequate.

Horse size and domestication: Early equid bones from the Czech Republic in the European context

Czech Academy of Sciences Publication Activity Database

Kyselý, René; Peške, L.

2016-01-01

Roč. 51, č. 1 (2016), s. 15-39 ISSN 0761-3032 Institutional support: RVO:67985912 Keywords : Horse (Equus) * E. hydruntinus * osteometry * domestication * Czech Republic * Bohemia * Neolithic * Copper Age * Bronze Age * LSI Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 0.607, year: 2016

Inorganic elements determination in human and animal whole blood samples by X-ray fluorescence technique (EDXRF); Determinacao de elementos quimicos inorganicos em amostras de sangue total humano e de animais de experimentacao (hamster dourado e cavalo da raca crioula) pela tecnica de fluorescencia de raios X (EDXRF)

Energy Technology Data Exchange (ETDEWEB)

Redigolo, Marcelo Miyada

2011-07-01

Blood is a suspension of cells contained in a complex liquid called plasma. The term 'whole blood' refers to samples with both solid and liquid parts. Inorganic elements are responsible for essential functions, such as osmotic regulation, cardiac frequency and contractibility, blood clotting and neuromuscular excitability. The determination of inorganic elements in corporeal fluids such as blood, serum, plasma, tissue and urine is used as a monitor for a part or the whole organism. In this work, the X-Ray fluorescence technique (EDXRF) was used for the determination of inorganic elements in whole blood samples from humans and animals (golden hamsters, Mesocricetus auratus and crioula breed horses, Equus caballus). The reference intervals of Na (1788 - 1826 {mu}g g'-{sup 1}), Mg (63 - 75 {mu}g g{sup -1}), P (602 - 676 {mu}g g{sup -1}), S (1519 - 1718 {mu}g g{sup -1}), Cl (2743 - 2867 {mu}g g{sup -1}), K (1508 - 1630 {mu}g g{sup -1}), Ca (214 - 228 {mu}g g'-{sup 1}), Cu (4 -6 {mu}g g{sup -1}) e Zn (1 - 3 {mu}g g'-{sup 1}) were determined for human blood. The reference intervals, for golden hamster blood were found to be: Na (1714 - 1819 {mu}g g{sup -1}), Mg (51 - 79 {mu}g g{sup -1}), P (970 - 1080 {mu}g g{sup -1}), S (1231 - 1739 {mu}g g{sup -1}), Cl (2775 - 2865 {mu}g g{sup -1}), K (1968 - 2248 {mu}g g{sup -1}), Ca (209 - 257 {mu}g g-1), Cu (4 - 6 {mu}g g{sup -1}) e Zn (3 - 5 {mu}g g{sup -1}). The reference intervals, for crioula breed horse blood, showed to be: Na (1955 - 2013 {mu}g g{sup -1}), Mg (51 - 75 {mu}g g{sup -1}), P (443 - 476 {mu}g g{sup -1}), S (1038 - 1140 {mu}g g{sup -}'1), Cl (2388 - 2574 {mu}g g{sup -1}), K (1678 - 1753 {mu}g g{sup -1}), Ca (202 - 213 {mu}g g{sup -1}), Cu (4,1 - 4,5 {mu}g g{sup -1}) e Zn (2,0 - 2,2 {mu}g g{sup -1}). Comparative study between NAA and EDXRF, both techniques showed the same performance for the analyses of biological matrices. The results contribute for the establishment of reference

Effective electron-electron and electron-phonon interactions in the Hubbard-Holstein model

International Nuclear Information System (INIS)

Aprea, G.; Di Castro, C.; Grilli, M. . E-mail marco.grilli@roma1.infn.it; Lorenzana, J.

2006-01-01

We investigate the interplay between the electron-electron and the electron-phonon interaction in the Hubbard-Holstein model. We implement the flow-equation method to investigate within this model the effect of correlation on the electron-phonon effective coupling and, conversely, the effect of phonons in the effective electron-electron interaction. Using this technique we obtain analytical momentum-dependent expressions for the effective couplings and we study their behavior for different physical regimes. In agreement with other works on this subject, we find that the electron-electron attraction mediated by phonons in the presence of Hubbard repulsion is peaked at low transferred momenta. The role of the characteristic energies involved is also analyzed

Electron-electron coincidence spectroscopies at surfaces

International Nuclear Information System (INIS)

Stefani, G.; Iacobucci, S.; Ruocco, A.; Gotter, R.

2002-01-01

In the past 20 years, a steadily increasing number of electron-electron coincidence experiments on atoms and molecules have contributed to a deeper understanding of electron-electron correlation effects. In more recent years this technique has been extended to the study of solid surfaces. This class of one photon IN two electrons OUT experiments will be discussed with an emphasis on grazing incidence geometry, that is expected to be particularly suited for studying surfaces. The crucial question of which is the dominant mechanism that leads to ejection of pairs of electron from the surface will be addressed. It will be shown that, depending on the kinematics chosen, the correlated behaviour of the pairs of electrons detected might be singled out from independent particle one

Ecological Monitoring and Compliance Program 2006 Report

Energy Technology Data Exchange (ETDEWEB)

David C. Anderson; Paul D. Greger; Derek B. Hall; Dennis J. Hansen; William K. Ostler

2007-03-01

The Ecological Monitoring and Compliance program (EMAC), funded through the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO), monitors the ecosystem of the Nevada Test Site (NTS) and ensures compliance with laws and regulations pertaining to NTS biota. This report summarizes the program's activities conducted by National Security Technologies LLC (NSTec) during the Calendar Year 2006. Program activities included: (a) biological surveys at proposed construction sites, (b) desert tortoise compliance, (c) ecosystem mapping and data management, (d) sensitive plant species monitoring, (e) sensitive and protected/regulated animal monitoring, (f) habitat monitoring, (g) habitat restoration monitoring, and (h) monitoring of the Nonproliferation Test and Evaluation Complex (NPTEC). Sensitive and protected/regulated species of the NTS include 44 plants, 1 mollusk, 2 reptiles, over 250 birds, and 26 mammals protected, managed, or considered sensitive as per state or federal regulations and natural resource agencies and organizations. The threatened desert tortoise (Gopherus agassizii) is the only species on the NTS protected under the Endangered Species Act. Biological surveys for the presence of sensitive and protected/regulated species and important biological resources on which they depend were conducted for 34 projects. A total of 342.1 hectares (ha) (845.37 acres [ac]) was surveyed for these projects. Sensitive and protected/regulated species and important biological resources found included: 2 inactive tortoise burrows, 2 western burrowing owls (Athene cunicularia hypugaea), several horses (Equus caballus), 2 active predator burrows, mature Joshua trees (Yucca brevifolia), yuccas and cacti; and also 1 bird nest (2 eggs), 1 barn owl (Tyto alba) and 2 great-horned owls (Bubo virginianus). NSTec provided a written summary report of all survey findings and mitigation recommendations, where applicable. All flagged burrows

Electron distribution function in electron-beam-excited plasmas

International Nuclear Information System (INIS)

Brau, C.A.

1976-01-01

In monatomic plasmas excited by high-intensity relativistic electron beams, the electron secondary distribution function is dominated by elastic electron-electron collisions at low electron energies and by inelastic electron-atom collisions at high electron energies (above the excitation threshold). Under these conditions, the total rate of excitation by inelastic collisions is limited by the rate at which electron-electron collisions relax the distribution function in the neighborhood of the excitation threshold. To describe this effect quantitatively, an approximate analytic solution of the electron Boltzmann equation is obtained, including both electron-electron and inelastic collisions. The result provides a simple formula for the total rate of excitation

Hard electronics; Hard electronics

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

Composição centesimal e teor de colesterol na carne de eqüinos (Equus caballus, Linneaus, 1758 machos e fêmeas agrupados por peso de carcaça Proximate composition and content of cholesterol in the meat of female and male equines (Equus cabalus, Linneaus 1758 with diferent carcasse weights

Directory of Open Access Journals (Sweden)

Antonio Carlos Andrade Junqueira

2005-04-01

Full Text Available O presente estudo foi conduzido em frigorífico comercial e as análises no Setor de Tecnologia de Carnes do Departamento de Ciências dos Alimentos da Universidade Federal de Lavras (UFLA. Com o objetivo de avaliar o efeito do sexo e categoria de peso sobre a composição centesimal e teor de colesterol, 20 eqüinos (10 machos castrados e 10 fêmeas foram abatidos e agrupados em categorias de peso ao abate preestabelecidas, sendo: C1( 88,82 a 97,88 kg; C2( 102,20 a 115,80 kg; C3(129,71 a 160,69 kg; C4(162,80 a 236,40 kg; com 5 animais por categoria. Os músculos longissimus dorsi (LD e semimembranosus (SM, após o abate, foram coletados e analisados: umidade, gordura, proteína e cinzas (AOAC, 1990 e o colesterol foi determinado por colorimetria (Bragagnolo, 1997. O modelo estatístico foi inteiramente casualizado, em esquema fatorial 2X4, e os dados foram analisadas pelo programa estatístico SAS. O fator sexo influenciou (pThe present study was conducted in a packing house, with the assays being done in the Sector of Meat Technology/Food Science Department of the Universidade Federal de Lavras (UFLA. With the objective of evaluating the effect of sex and category of weight on the meat proximate composition and content of cholesterol, 20 equines (10 castrated males and 10 females were slaughtered and grouped in pre-established categories of weight: C1 (88.82 to 97.88 kg; C2 (102.20 to 115.80 kg, C3 (129.7 to 160.69 kg and C4 (162.80 to 236.40 kg; with 5 animals for each category. The muscles longissimus dorsi (LD and semimembranosus (SM were collected and analyzed for: moisture, fat, protein and ashes (AOAC, 1990 and the cholesterol was determined by colorimetry (Bragagnolo, 1997. The statistical model was completely randomized, in factorial scheme 2X4, and the data were analyzed through the statistical program SAS. The factor sex influenced (p<0,05 the contents of cholesterol in LD muscle, with average values (in base of dry natural material of 36.77% and 56.08%, for males and females, respectively. The factors category of weight and sex had no influence in the values of moisture, protein, ash and fat in the muscles LD and SM, the averages seing: ashes (0.70% and 1.66%; moisture (75.53% and 75.83%; fat (0.67% and 2.03%; protein (21.63% and 22.49% for the muscles LD and SM, respectively. The rates of these chemical components show that, the meat of equines obtained in a packing house presents a high quantity of protein and low quantity of fat and can be considered as a light meat.

Global evolution of Equidae and Gomphotheriidae from South America.

Science.gov (United States)

Prado, José L; Alberdi, María T

2014-08-01

The contemporary South American mammalian communities were determined by the emergence of the Isthmus of Panama and by the profound climatic oscillations during the Pleistocene. Horses and gomphotheres were 2 very conspicuous groups of immigrant mammals from North America that arrived in South America during the Pleistocene. The present study compiles updated data on the phylogeny, systematics and ecology of both groups in South America. The horses in South America are represented by 2 genera, Hippidion and Equus, as are the gomphotheres, represented by Cuvieronius and Stegomastodon. Both genera of horses include small (Hippidion devillei, H. saldiasi, E. andium and E. insulatus) and large forms (Equus neogeus and H. principale), which dispersed into South America using 2 different routes. The possible model for this dispersion indicates that the small forms used the Andes corridor, while larger horses dispersed through the eastern route and through some coastal areas. In the case of gomphotheres, Cuvieronius and Stegomastodon reached South America in 2 independent dispersal events, and Cuvieronius dispersed across the Andean corridor, while large Stegomastodon spread along the eastern route. Horses and gomphotheres present values of δ(13) C from woodlands to C4 grasslands. Hippidion present lower values of δ(13) C than Equus in the late Pleistocene, whereas the gomphotheres diverge from value of δ(18) O, reflecting that Cuvieronius inhabited the Andean corridor and Stegomastodon dispersed through eastern plains. The gomphothere and horse species recorded in South America became extinct around the time that humans arrived. © 2013 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

Electron radiography

Science.gov (United States)

Merrill, Frank E.; Morris, Christopher

2005-05-17

A system capable of performing radiography using a beam of electrons. Diffuser means receive a beam of electrons and diffuse the electrons before they enter first matching quadrupoles where the diffused electrons are focused prior to the diffused electrons entering an object. First imaging quadrupoles receive the focused diffused electrons after the focused diffused electrons have been scattered by the object for focusing the scattered electrons. Collimator means receive the scattered electrons and remove scattered electrons that have scattered to large angles. Second imaging quadrupoles receive the collimated scattered electrons and refocus the collimated scattered electrons and map the focused collimated scattered electrons to transverse locations on an image plane representative of the electrons' positions in the object.

Electron transfer from electronic excited states to sub-vacuum electron traps in amorphous ice

International Nuclear Information System (INIS)

Vichnevetski, E.; Bass, A.D.; Sanche, L.

2000-01-01

We investigate the electron stimulated yield of electronically excited argon atoms (Ar * ) from monolayer quantities of Ar deposited onto thin films of amorphous ice. Two peaks of narrow width ( - electron-exciton complex into exciton states, by the transfer of an electron into a sub-vacuum electron state within the ice film. However, the 10.7 eV feature is shifted to lower energy since electron attachment to Ar occurs within small pores of amorphous ice. In this case, the excess electron is transferred into an electron trap below the conduction band of the ice layer

Monte Carlo study of electron relaxation in graphene with spin polarized, degenerate electron gas in presence of electron-electron scattering

Science.gov (United States)

Borowik, Piotr; Thobel, Jean-Luc; Adamowicz, Leszek

2017-12-01

The Monte Carlo simulation method is applied to study the relaxation of excited electrons in monolayer graphene. The presence of spin polarized background electrons population, with density corresponding to highly degenerate conditions is assumed. Formulas of electron-electron scattering rates, which properly account for electrons presence in two energetically degenerate, inequivalent valleys in this material are presented. The electron relaxation process can be divided into two phases: thermalization and cooling, which can be clearly distinguished when examining the standard deviation of electron energy distribution. The influence of the exchange effect in interactions between electrons with parallel spins is shown to be important only in transient conditions, especially during the thermalization phase.

75 FR 43853 - Endangered and Threatened Wildlife and Plants; Final Rule to List the Medium Tree-Finch...

Science.gov (United States)

2010-07-27

... confirmation of the success of the goat eradication program, was provided by one peer reviewer and has been... habitat is unprotected. A large amount of the highlands has been cleared or altered for farming. Much of... animals include goats (Capra hircus), donkeys (Equus asinus), cattle (Bos taurus), and pigs (Sus scrofa...

Evolutionary Genomics and Conservation of the Endangered Przewalski’s Horse

DEFF Research Database (Denmark)

Der Sarkissian, Clio; Ermini, Luca; Schubert, Mikkel

2015-01-01

Przewalski’s horses (PHs, Equus ferus ssp. przewalskii) were discovered in the Asian steppes in the 1870s and represent the last remaining true wild horses. PHs became extinct in the wild in the 1960s but survived in captivity, thanks to major conservation efforts. The current population is still...

77 FR 33100 - Endangered and Threatened Wildlife and Plants; Technical Correction for African Wild Ass

Science.gov (United States)

2012-06-05

... telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-877-8339... recognizes the African wild ass as Equus asinus (CITES Resolution Conf. 12.11 (Rev. CoP15), Standard... the problems it created for enforcement officials, the Parties agreed to deviate from Wilson and...

Electron attachment cross sections obtained from electron attachment spectroscopy

International Nuclear Information System (INIS)

Popp, P.; Baumbach, J.I.; Leonhardt, J.W.; Mothes, S.

1988-01-01

Electron capture detectors have a high sensitivity for substances with high thermal electron attachment cross sections. The electron attachment spectroscopy makes it possible to change the mean electron energy in such a way that the maximum for dissociative electron attachment is reached. Thus, best operation modes of the detection system as well as significant dependencies of electron attachment coefficients are available. Cross sections for electron attachment as a function of the electron energy are obtained with the knowledge of electron energy distribution functions from Boltzmann equation analysis by a special computer code. A disadvantage of this electron attachment spectroscopy is the superposition of space charge effects due to the decrease of the electron drift velocity with increasing mean electron energy. These influences are discussed. (author)

Electron beam effects in auger electron spectroscopy and scanning electron microscopy

International Nuclear Information System (INIS)

Fontaine, J.M.; Duraud, J.P.; Le Gressus, C.

1979-01-01

Electron beam effects on Si(100) and 5% Fe/Cr alloy samples have been studied by measurements of the secondary electron yield delta, determination of the surface composition by Auger electron spectroscopy and imaging with scanning electron microscopy. Variations of delta as a function of the accelerating voltage Esub(p) (0.5 -9 Torr has no effect on technological samples covered with their reaction layers; the sensitivities to the beam depend rather on the earlier mechanical, thermal and chemical treatment of the surfaces. (author)

The effect of electron-electron interaction induced dephasing on electronic transport in graphene nanoribbons

Energy Technology Data Exchange (ETDEWEB)

Kahnoj, Sina Soleimani; Touski, Shoeib Babaee [School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395-515, Tehran (Iran, Islamic Republic of); Pourfath, Mahdi, E-mail: pourfath@ut.ac.ir, E-mail: pourfath@iue.tuwien.ac.at [School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395-515, Tehran (Iran, Islamic Republic of); Institute for Microelectronics, TU Wien, Gusshausstrasse 27–29/E360, 1040 Vienna (Austria)

2014-09-08

The effect of dephasing induced by electron-electron interaction on electronic transport in graphene nanoribbons is theoretically investigated. In the presence of disorder in graphene nanoribbons, wavefunction of electrons can set up standing waves along the channel and the conductance exponentially decreases with the ribbon's length. Employing the non-equilibrium Green's function formalism along with an accurate model for describing the dephasing induced by electron-electron interaction, we show that this kind of interaction prevents localization and transport of electrons remains in the diffusive regime where the conductance is inversely proportional to the ribbon's length.

Electron Beam Generation in Tevatron Electron Lenses

International Nuclear Information System (INIS)

Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

2006-01-01

New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

Electron beam generation in Tevatron electron lenses

International Nuclear Information System (INIS)

Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

2006-01-01

New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

Electronic technology

International Nuclear Information System (INIS)

Kim, Jin Su

2010-07-01

This book is composed of five chapters, which introduces electronic technology about understanding of electronic, electronic component, radio, electronic application, communication technology, semiconductor on its basic, free electron and hole, intrinsic semiconductor and semiconductor element, Diode such as PN junction diode, characteristic of junction diode, rectifier circuit and smoothing circuit, transistor on structure of transistor, characteristic of transistor and common emitter circuit, electronic application about electronic equipment, communication technology and education, robot technology and high electronic technology.

Social behaviour of African Equidae | Klingel | African Zoology

African Journals Online (AJOL)

Two basically different forms of social organisation have been discovered in the equids. Type one is represented by the plains zebra, Equus quagga, and by the mountain zebra, E. zebra, who live in non-territorial and coherent family groups and stallion groups. The young leave their original families in a set pattern.

The Electron

Energy Technology Data Exchange (ETDEWEB)

Thomson, George

1972-01-01

Electrons are elementary particles of atoms that revolve around and outside the nucleus and have a negative charge. This booklet discusses how electrons relate to electricity, some applications of electrons, electrons as waves, electrons in atoms and solids, the electron microscope, among other things.

Determination of the electron-electron collisional frequency by means of plasma electron spectroscopy

International Nuclear Information System (INIS)

Kolokolov, N.B.; Kudryavtsev, A.A.; Romanenko, V.A.

1989-01-01

Methods of controlling fast part of electron distribution function (DF) in nonlocal regime of current-free plasma are suggested and realized. Artificially created step in DF fast part has a simple link with frequencies of electron-electron and elastic electron-atom collisions that may be defined in the corresponding experiments

Electron beam-plasma interaction and electron-acoustic solitary waves in a plasma with suprathermal electrons

Science.gov (United States)

Danehkar, A.

2018-06-01

Suprathermal electrons and inertial drifting electrons, so called electron beam, are crucial to the nonlinear dynamics of electrostatic solitary waves observed in several astrophysical plasmas. In this paper, the propagation of electron-acoustic solitary waves (EAWs) is investigated in a collisionless, unmagnetized plasma consisting of cool inertial background electrons, hot suprathermal electrons (modeled by a κ-type distribution), and stationary ions. The plasma is penetrated by a cool electron beam component. A linear dispersion relation is derived to describe small-amplitude wave structures that shows a weak dependence of the phase speed on the electron beam velocity and density. A (Sagdeev-type) pseudopotential approach is employed to obtain the existence domain of large-amplitude solitary waves, and investigate how their nonlinear structures depend on the kinematic and physical properties of the electron beam and the suprathermality (described by κ) of the hot electrons. The results indicate that the electron beam can largely alter the EAWs, but can only produce negative polarity solitary waves in this model. While the electron beam co-propagates with the solitary waves, the soliton existence domain (Mach number range) becomes narrower (nearly down to nil) with increasing the beam speed and the beam-to-hot electron temperature ratio, and decreasing the beam-to-cool electron density ratio in high suprathermality (low κ). It is found that the electric potential amplitude largely declines with increasing the beam speed and the beam-to-cool electron density ratio for co-propagating solitary waves, but is slightly decreased by raising the beam-to-hot electron temperature ratio.

Ancient DNA provides new insight into the maternal lineages and domestication of Chinese donkeys.

Science.gov (United States)

Han, Lu; Zhu, Songbiao; Ning, Chao; Cai, Dawei; Wang, Kai; Chen, Quanjia; Hu, Songmei; Yang, Junkai; Shao, Jing; Zhu, Hong; Zhou, Hui

2014-11-30

The donkey (Equus asinus) is an important domestic animal that provides a reliable source of protein and method of transportation for many human populations. However, the process of domestication and the dispersal routes of the Chinese donkey are still unclear, as donkey remains are sparse in the archaeological record and often confused with horse remains. To explore the maternal origins and dispersal route of Chinese donkeys, both mitochondrial DNA D-loop and cytochrome b gene fragments of 21 suspected donkey remains from four archaeological sites in China were amplified and sequenced. Molecular methods of species identification show that 17 specimens were donkeys and three samples had the maternal genetic signature of horses. One sample that dates to about 20,000 years before present failed to amplify. In this study, the phylogenetic analysis reveals that ancient Chinese donkeys have high mitochondrial DNA diversity and two distinct mitochondrial maternal lineages, known as the Somali and Nubian lineages. These results indicate that the maternal origin of Chinese domestic donkeys was probably related to the African wild ass, which includes the Nubian wild ass (Equus africanus africanus) and the Somali wild ass (Equus africanus somaliensis). Combined with historical records, the results of this study implied that domestic donkeys spread into west and north China before the emergence of the Han dynasty. The number of Chinese domestic donkeys had increased primarily to meet demand for the expansion of trade, and they were likely used as commodities or for shipping goods along the Silk Road during the Tang Dynasty, when the Silk Road reached its golden age. This study is the first to provide valuable ancient animal DNA evidence for early trade between African and Asian populations. The ancient DNA analysis of Chinese donkeys also sheds light on the dynamic process of the maternal origin, domestication, and dispersal route of ancient Chinese donkeys.

Clinical and Histopathological Evaluation of Cutaneous Pythiosis in Donkeys (Equusasinus

Directory of Open Access Journals (Sweden)

José Alberto Cardona Álvarez

2013-06-01

Full Text Available The purpose of this study was to evaluate and characterize the clinical and histopathological aspects of cutaneous pythiosis in donkeys (Equus asinus in the Department of Cordoba, Colombia. A descriptive, non-probability study was conducted on domesticated animals. Nine donkeys clinically and histopathologically diagnosed with cutaneous pythiosis were analyzed. After describing the cases, a serious, crater-shaped granulomatous ulcer was observed, with necrotic tissue, a tumor appearance, abundant fibrinous-bloody exudation and yellowish-white caseous material known as kunkers. The lesions were found in the members, ventral abdomen and chest of the animals. Histopathologically, with the hematoxylin-eosin staining, severe pyogranulomatous dermatitis was observed, with abundant eosinophilic and neutrophilic inflammatory infiltrate; with the Grocott staining, hyphae with septa were found, partially branching into a right angle and brown in color. The definitive diagnosis of the disease was based on the clinical features, the differential diagnosis and the histopathological findings. The diagnosis of cutaneous pythiosis was conclusive. This study becomes the first report of this disease in donkeys (Equus asinus in the department of Córdoba and in Colombia.

Electronic Government and Electronic Participation

NARCIS (Netherlands)

Tambouris, E; Scholl, H.J.; Janssen, M.F.W.H.A.; Wimmer, M.A.; Tarabanis, K; Gascó, M; Klievink, A.J.; Lindgren, I; Milano, M; Panagiotopoulos, P; Pardo, T.A.; Parycek, P; Sæbø, Ø

2016-01-01

Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies.This book presents papers from the 14th International Federation for Information

Electronic Government and Electronic Participation

NARCIS (Netherlands)

Tambouris, E.; Scholl, H.J.; Janssen, M.F.W.H.A.; Wimmer, M.A.; Tarabanis, K.; Gascó, M.; Klievink, A.J.; Lindgren, I.; Milano, M.; Panagiotopoulos, P.; Pardo, T.A.; Parycek, P.; Sæbø, O.

2015-01-01

Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies. This book presents papers from the 14th International Federation for Information

Electron detector

International Nuclear Information System (INIS)

Hashimoto, H.; Mogami, A.

1975-01-01

A device for measuring electron densities at a given energy level in an electron beam or the like having strong background noise, for example, in the detection of Auger electric energy spectrums is described. An electron analyzer passes electrons at the given energy level and at the same time electrons of at least one adjacent energy level. Detecting means associated therewith produce signals indicative of the densities of the electrons at each energy level and combine these signals to produce a signal indicative of the density of the electrons of the given energy level absent background noise

Electron-electron interactions in artificial graphene

Science.gov (United States)

Rasanen, Esa

2013-03-01

Recent advances in the creation and modulation of graphenelike systems are introducing a science of ``designer Dirac materials.'' In its original definition, artificial graphene is a man-made nanostructure that consists of identical potential wells (quantum dots) arranged in an adjustable honeycomb lattice in the two-dimensional electron gas. As our ability to control the quality of artificial graphene samples improves, so grows the need for an accurate theory of its electronic properties, including the effects of electron-electron interactions. Here we determine those effects on the band structure and on the emergence of Dirac points, and discuss future investigations and challenges in this field.

Decal electronics for printed high performance cmos electronic systems

KAUST Repository

Hussain, Muhammad Mustafa

2017-11-23

High performance complementary metal oxide semiconductor (CMOS) electronics are critical for any full-fledged electronic system. However, state-of-the-art CMOS electronics are rigid and bulky making them unusable for flexible electronic applications. While there exist bulk material reduction methods to flex them, such thinned CMOS electronics are fragile and vulnerable to handling for high throughput manufacturing. Here, we show a fusion of a CMOS technology compatible fabrication process for flexible CMOS electronics, with inkjet and conductive cellulose based interconnects, followed by additive manufacturing (i.e. 3D printing based packaging) and finally roll-to-roll printing of packaged decal electronics (thin film transistors based circuit components and sensors) focusing on printed high performance flexible electronic systems. This work provides the most pragmatic route for packaged flexible electronic systems for wide ranging applications.

Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

Energy Technology Data Exchange (ETDEWEB)

Han, Myung-Geun, E-mail: mghan@bnl.gov [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Garlow, Joseph A. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States); Marshall, Matthew S.J.; Tiano, Amanda L. [Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Wong, Stanislaus S. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Cheong, Sang-Wook [Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854 (United States); Walker, Frederick J.; Ahn, Charles H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520 (United States); Zhu, Yimei [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2017-05-15

Highlights: • Electron-beam-induced-current (EBIC) and active secondary-electron voltage-contrast (SE-VC) are demonstrated in STEM mode combined with in situ electrical biasing in a TEM. • Electrostatic potential maps in ferroelectric thin films, multiferroic nanowires, and single crystals obtained by off-axis electron holography were compared with EBIC and SE-VC data. • Simultaneous EBIC and active SE-VC performed with atomic resolution STEM are demonstrated. - Abstract: The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.

Electronic Commerce and Electronic Business

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

This special issue is motivated by the recent upsurge of research activity in the areas of electronic commerce and electronic business both in India and all over the world. The current ... Monte Carlo methods for pricing financial options are then.

Electron optical characteristics of a concave electrostatic electron mirror for a scanning electron microscope

International Nuclear Information System (INIS)

Hamarat, R.T.; Witzani, J.; Hoerl, E.M.

1984-08-01

Numerical computer calculations are used to explore the design characteristics of a concave electrostatic electron mirror for a mirror attachment for a conventional scanning electron microscope or an instrument designed totally as a scanning electron mirror microscope. The electron paths of a number of set-ups are calculated and drawn graphically in order to find the optimum shape and dimensions of the mirror geometry. This optimum configuration turns out to be the transition configuration between two cases of electron path deflection, towards the optical axis of the system and away from it. (Author)

Asia Beyond the Border: Physical Geography - Central and Northeastern Asia -

Science.gov (United States)

1961-03-21

Shan: the kiang species ( Equus hemionus kiang). Forest hoofed animals are characteristic only for the western and northern mountain groups which are...severe winter olinate or its hot suremers» ’ „ ,, . •The Hwang Ho has a bread a»4>in S»*** a low vamy «»«»S tee sand and alluvial desert

Fulltext PDF

Indian Academy of Sciences (India)

fragility at that, for Equus died in the land of its birth and had to be salvaged from a stock that had migrated elsewhere. (In a larger sense, horses form one of three dwindling lines. - tapirs and rhinos are the others - that now represent all the diversity of the formerly dominant order Perissodactyla, or odd-toed ungulates, ...

Electronic processes in organic electronics bridging nanostructure, electronic states and device properties

CERN Document Server

Kudo, Kazuhiro; Nakayama, Takashi; Ueno, Nobuo

2015-01-01

The book covers a variety of studies of organic semiconductors, from fundamental electronic states to device applications, including theoretical studies. Furthermore, innovative experimental techniques, e.g., ultrahigh sensitivity photoelectron spectroscopy, photoelectron yield spectroscopy, spin-resolved scanning tunneling microscopy (STM), and a material processing method with optical-vortex and polarization-vortex lasers, are introduced. As this book is intended to serve as a textbook for a graduate level course or as reference material for researchers in organic electronics and nanoscience from electronic states, fundamental science that is necessary to understand the research is described. It does not duplicate the books already written on organic electronics, but focuses mainly on electronic properties that arise from the nature of organic semiconductors (molecular solids). The new experimental methods introduced in this book are applicable to various materials (e.g., metals, inorganic and organic mater...

Decal electronics for printed high performance cmos electronic systems

KAUST Repository

Hussain, Muhammad Mustafa; Sevilla, Galo Torres; Cordero, Marlon Diaz; Kutbee, Arwa T.

2017-01-01

High performance complementary metal oxide semiconductor (CMOS) electronics are critical for any full-fledged electronic system. However, state-of-the-art CMOS electronics are rigid and bulky making them unusable for flexible electronic applications

Precession mechanism of spin relaxation at frequent electron-electron collisions

CERN Document Server

Glazov, M M

2002-01-01

It is shown that the spin relaxation mechanism in the two-dimensional electron gas, is controlled not only through the electron pulse relaxation processes, determining the mobility, but through the electron-electron collisions as well. It is decided to use the kinetic equation, describing the electron spin mixing in the k-space, for determining the spin relaxation time tau sub s at frequent electron-electron collisions. The tau sub s time is calculated for the nondegenerated electron gas both with an account and with no account of the exchange interaction

Practical electronics handbook

CERN Document Server

Sinclair, Ian R

2013-01-01

Practical Electronics Handbook, Third Edition provides the frequently used and highly applicable principles of electronics and electronic circuits.The book contains relevant information in electronics. The topics discussed in the text include passive and active discrete components; linear and digital I.C.s; microprocessors and microprocessor systems; digital-analogue conversions; computer aids in electronics design; and electronic hardware components.Electronic circuit constructors, service engineers, electronic design engineers, and anyone with an interest in electronics will find the book ve

Composition quantification of electron-transparent samples by backscattered electron imaging in scanning electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Müller, E., E-mail: erich.mueller@kit.edu; Gerthsen, D.

2017-02-15

The contrast of backscattered electron (BSE) images in scanning electron microscopy (SEM) depends on material parameters which can be exploited for composition quantification if some information on the material system is available. As an example, the In-concentration in thin In{sub x}Ga{sub 1−x}As layers embedded in a GaAs matrix is analyzed in this work. The spatial resolution of the technique is improved by using thin electron-transparent specimens instead of bulk samples. Although the BSEs are detected in a comparably small angular range by an annular semiconductor detector, the image intensity can be evaluated to determine the composition and local thickness of the specimen. The measured intensities are calibrated within one single image to eliminate the influence of the detection and amplification system. Quantification is performed by comparison of experimental and calculated data. Instead of using time-consuming Monte-Carlo simulations, an analytical model is applied for BSE-intensity calculations which considers single electron scattering and electron diffusion. - Highlights: • Sample thickness and composition are quantified by backscattered electron imaging. • A thin sample is used to achieve spatial resolution of few nanometers. • Calculations are carried out with a time-saving electron diffusion model. • Small differences in atomic number and density detected at low electron energies.

Nonlinear electron-acoustic rogue waves in electron-beam plasma system with non-thermal hot electrons

Science.gov (United States)

Elwakil, S. A.; El-hanbaly, A. M.; Elgarayh, A.; El-Shewy, E. K.; Kassem, A. I.

2014-11-01

The properties of nonlinear electron-acoustic rogue waves have been investigated in an unmagnetized collisionless four-component plasma system consisting of a cold electron fluid, non-thermal hot electrons obeying a non-thermal distribution, an electron beam and stationary ions. It is found that the basic set of fluid equations is reduced to a nonlinear Schrodinger equation. The dependence of rogue wave profiles on the electron beam and energetic population parameter are discussed. The results of the present investigation may be applicable in auroral zone plasma.

Electron-cyclotron-resonant-heated electron distribution functions

International Nuclear Information System (INIS)

Matsuda, Y.; Nevins, W.M.; Cohen, R.H.

1981-01-01

Recent studies at Lawrence Livermore National Laboratory (LLNL) with a bounce-averaged Fokker-Planck code indicate that the energetic electron tail formed by electron-cyclotron resonant heating (ECRH) at the second harmonic is not Maxwellian. We present the results of our bounce-averaged Fokker-Planck code along with some simple analytic models of hot-electron distribution functions

Attainment of Electron Beam Suitable for Medium Energy Electron Cooling

International Nuclear Information System (INIS)

Seletskiy, Sergey M.; Rochester U.

2005-01-01

Electron cooling of charged particle beams is a well-established technique at electron energies of up to 300 keV. However, up to the present time the advance of electron cooling to the MeV-range energies has remained a purely theoretical possibility. The electron cooling project at Fermilab has recently demonstrated the first cooling of 8.9 GeV/c antiprotons in the Recycler ring, and therefore, has proved the validity of the idea of relativistic electron cooling. The Recycler Electron Cooler (REC) is the key component of the Tevatron Run II luminosity upgrade project. Its performance depends critically on the quality of electron beam. A stable electron beam of 4.3 MeV carrying 0.5 A of DC current is required. The beam suitable for the Recycler Electron Cooler must have an angular spread not exceeding 200 (micro)rad. The full-scale prototype of the REC was designed, built and tested at Fermilab in the Wideband laboratory to study the feasibility of attaining the high-quality electron beam. In this thesis I describe various aspects of development of the Fermilab electron cooling system, and the techniques used to obtain the electron beam suitable for the cooling process. In particular I emphasize those aspects of the work for which I was principally responsible. Chapter 1 is an introduction where I describe briefly the theory and the history of electron cooling, and derive the requirements to the quality of electron beam and requirements to the basic parameters of the Recycler Electron Cooler. Chapter 2 is devoted to the theoretical consideration of the motion of electrons in the cooling section, description of the cooling section and of the measurement of the magnetic fields. In Chapter 3 I consider different factors that increase the effective electron angle in the cooling section and suggest certain algorithms for the suppression of parasitic angles. Chapter 4 is devoted to the measurements of the energy of the electron beam. In the concluding Chapter 5 I review

Double differential distributions of electron emission in ion-atom and electron-atom collisions using an electron spectrometer

International Nuclear Information System (INIS)

Misra, Deepankar; Thulasiram, K.V.; Fernandes, W.; Kelkar, Aditya H.; Kadhane, U.; Kumar, Ajay; Singh, Yeshpal; Gulyas, L.; Tribedi, Lokesh C.

2009-01-01

We study electron emission from atoms and molecules in collisions with fast electrons and heavy ions (C 6+ ). The soft collision electrons (SE), two center electron emission (TCEE), the binary encounter (BE) events and the KLL Auger lines along with the elastically scattered peaks (in electron collisions) are studied using a hemispherical electrostatic electron analyzer. The details of the measurements along with description of the spectrometer and data acquisition system are given. The angular distributions of the low energy (few eV) electrons in soft collisions and the binary encounter electrons at keV energies are compared with quantum mechanical models based on the first Born (B1) and the continuum distorted wave-Eikonal initial state approximation (CDW-EIS).

VIRTUAL ELECTRONIC COMPONENTS OF THE ELECTRONIC EQUIPMENT

Directory of Open Access Journals (Sweden)

E. Lazarevich

2013-01-01

Full Text Available The article is present new idea of the creation, developments and improvements of the electronic equipment of complex systems by means of the virtual electronic components. The idea of the virtual electronic components is a presentation and perception of the creation and developments of the equipment on two forming: real – in the manner of standard marketed block of the intellectual property and image – in the manner of virtual component. The real component in most cases slows the development of the electronic equipment. The imaginary component is the «locomotive» of development of the electronic equipment. The Imaginary component contains the scientific has brushed against developer. The scientific has brushed against developer reveals of itself in the manner of virtual component on the modern level of the design rates of microelectronics.

A new stage of nuclear electronics-particle electronics

International Nuclear Information System (INIS)

Xi Deming

1987-01-01

The rapid development of high energy physics experiments has pushed the nuclear electronics to a new stage, i.e. the particle electronics. In this paper the background, main features and recent trends of the particle electronics are expounded

Electron transport effects in ion induced electron emission

Energy Technology Data Exchange (ETDEWEB)

Dubus, A. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. FD Roosevelt, B-1050 Brussels (Belgium)]. E-mail: adubus@ulb.ac.be; Pauly, N. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. FD Roosevelt, B-1050 Brussels (Belgium); Roesler, M. [Karl-Pokern-Str. 12, D-12587 Berlin (Germany)

2007-03-15

Ion induced electron emission (IIEE) is usually described as a three-step process, i.e. electron excitation by the incident projectile, electron transport (and multiplication) and electron escape through the potential barrier at the surface. In many cases, the first step of the process has been carefully described. The second step of the process, i.e. electron transport and multiplication, has often been treated in a very rough way, a simple decreasing exponential law being sometimes used. It is precisely the aim of the present work to show the importance of a correct description of electron transport and multiplication in a theoretical calculation of IIEE. A short overview of the electron transport models developed for IIEE is given in this work. The so-called 'Infinite medium slowing-down model' often used in recent works is evaluated by means of Monte Carlo simulations. In particular, the importance of considering correctly the semi-infinite character of the medium and the boundary condition at the vacuum-medium interface is discussed. Quantities like the electron escape depth are also briefly discussed. This evaluation has been performed in the particular case of protons (25keV

Studying electron-PAG interactions using electron-induced fluorescence

Science.gov (United States)

Narasimhan, Amrit; Grzeskowiak, Steven; Ostrander, Jonathan; Schad, Jonathon; Rebeyev, Eliran; Neisser, Mark; Ocola, Leonidas E.; Denbeaux, Gregory; Brainard, Robert L.

2016-03-01

In extreme ultraviolet (EUV) lithography, 92 eV photons are used to expose photoresists. Typical EUV resists are organic-based and chemically amplified using photoacid generators (PAGs). Upon exposure, PAGs produce acids which catalyze reactions that result in changes in solubility. In EUV lithography, photo- and secondary electrons (energies of 10- 80 eV) play a large role in PAG acid-production. Several mechanisms for electron-PAG interactions (e.g. electron trapping, and hole-initiated chemistry) have been proposed. The aim of this study is to explore another mechanism - internal excitation - in which a bound PAG electron can be excited by receiving energy from another energetic electron, causing a reaction that produces acid. This paper explores the mechanism of internal excitation through the analogous process of electron-induced fluorescence, in which an electron loses energy by transferring that energy to a molecule and that molecule emits a photon rather than decomposing. We will show and quantify electron-induced fluorescence of several fluorophores in polymer films to mimic resist materials, and use this information to refine our proposed mechanism. Relationships between the molecular structure of fluorophores and fluorescent quantum yield may aid in the development of novel PAGs for EUV lithography.

Electron-electron Thomas peak in fast transfer ionization

International Nuclear Information System (INIS)

Tolmanov, S. G.; McGuire, J. H.

2000-01-01

''Thomas process'' is a name used for a family of singular two-step processes that can lead to electron transfer. The Thomas process of the ''second kind,'' occurring in reactions with both transfer and ionization, utilizes the e-e scattering in the second step, so this Thomas process requires the dynamics of the electron-electron interaction. We calculate numerically the second order element of an S matrix and corresponding cross sections for the transfer ionization process. We find that the position and shape of the Thomas peak depend on both electron-electron and the electron-nucleus interaction. Also the direct and exchange amplitudes are equal at the peak position. We test the peaking approximation used for transfer ionization. Our results can be compared to experimental results for p + +He→H+He 2+ +e - . (c) 2000 The American Physical Society

Electron Tree

DEFF Research Database (Denmark)

Appelt, Ane L; Rønde, Heidi S

2013-01-01

The photo shows a close-up of a Lichtenberg figure – popularly called an “electron tree” – produced in a cylinder of polymethyl methacrylate (PMMA). Electron trees are created by irradiating a suitable insulating material, in this case PMMA, with an intense high energy electron beam. Upon discharge......, during dielectric breakdown in the material, the electrons generate branching chains of fractures on leaving the PMMA, producing the tree pattern seen. To be able to create electron trees with a clinical linear accelerator, one needs to access the primary electron beam used for photon treatments. We...... appropriated a linac that was being decommissioned in our department and dismantled the head to circumvent the target and ion chambers. This is one of 24 electron trees produced before we had to stop the fun and allow the rest of the accelerator to be disassembled....

Electronic Raman response in electron-doped cuprate superconductors

International Nuclear Information System (INIS)

Geng Zhihao; Feng Shiping

2012-01-01

The electronic Raman response in the electron-doped cuprate superconductors is studied based on the t-t'-J model. It is shown that although the domelike shape of the doping dependent peak energy in the B 2g symmetry is a common feature for both electron-doped and hole-doped cuprate superconductors, there are pronounced deviations from a cubic response in the B 2g channel and a linear response in the B 2g channel for the electron-doped case in the low energy limit. It is also shown that these pronounced deviations are mainly caused by a nonmonotonic d-wave gap in the electron-doped cuprate superconductors.

Spectroscopy of electron irradiated polymers in electron microscope

International Nuclear Information System (INIS)

Faraj, S.H.; Salih, S.M.

1981-01-01

The damage induced by energetic electrons in the course of irradiation of polymers in a transmission electron microscope was investigated spectroscopically. Damage on the molecular level has been detected at very low exposure doses. These effects have been induced by electron doses less than that received by the specimen when it is situated at its usual place of the specimen stage in the electron microscope by a factor of 1,000. (author)

Electron spectroscopy in the fundamental process of electron-nucleus bremsstrahlung

International Nuclear Information System (INIS)

Hillenbrand, Pierre-Michel

2013-07-01

Within the scope of this thesis the fundamental process of electron-nucleus bremsstrahlung was studied in inverse kinematics at the Experimental Storage Ring ESR at GSI. For the system U 88+ + N 2 at 90 MeV/u it was shown, that by using inverse kinematics coincidence measurements between the scattered electron and the emitted photon can be performed for the case, in which the incoming electron transfers almost all of its kinetic energy onto the emitted photon. The sensitivity to the fundamental process could be achieved by measuring triple differential cross sections as a function of the emission angle of the photon and the scattered electron as well as the energy of the scattered electron. The optics of the magnetic electron spectrometer used were thoroughly revised and optimized to the experimental requirements. Analyzing different coincidences in this collision system, it was possible to determine the contributions to the electron distribution arising from radiative electron capture to the projectile continuum, nonradiative electron capture to the projectile continuum, and electron loss to the projectile continuum. The experimental results of each of these processes were compared to theoretical calculations. The electron spectra for the radiative and the nonradiative electron capture to continuum clearly reproduce the opposite asymmetry predicted by theory. Furthermore electron spectra for collisions of U 28+ with different gases were measured.

`Twisted' electrons

Science.gov (United States)

Larocque, Hugo; Kaminer, Ido; Grillo, Vincenzo; Leuchs, Gerd; Padgett, Miles J.; Boyd, Robert W.; Segev, Mordechai; Karimi, Ebrahim

2018-04-01

Electrons have played a significant role in the development of many fields of physics during the last century. The interest surrounding them mostly involved their wave-like features prescribed by the quantum theory. In particular, these features correctly predict the behaviour of electrons in various physical systems including atoms, molecules, solid-state materials, and even in free space. Ten years ago, new breakthroughs were made, arising from the new ability to bestow orbital angular momentum (OAM) to the wave function of electrons. This quantity, in conjunction with the electron's charge, results in an additional magnetic property. Owing to these features, OAM-carrying, or twisted, electrons can effectively interact with magnetic fields in unprecedented ways and have motivated materials scientists to find new methods for generating twisted electrons and measuring their OAM content. Here, we provide an overview of such techniques along with an introduction to the exciting dynamics of twisted electrons.

Population ecology of feral horses in an era of fertility control management

Science.gov (United States)

Ransom, J.I.

2012-01-01

Management of wildlife often requires intervention to regulate growth of populations that would otherwise become overabundant. Controlling fecundity using contraceptives has become an increasingly popular tool for attempting to manage locally overabundant wildlife species, but the population-level effects of such applications are largely unknown. Contraceptive treatments can produce unexpected feedbacks that act on births, survival, immigration, and emigration. Such feedbacks may considerably influence our ability to regulate populations using fertility control. I followed feral horses (Equus caballus) in three intensively managed populations to assess longitudinal treatment effects on demography. The transient contraceptive porcine zona pellucida (PZP) produced longer duration of infertility than intended. Repeated PZP vaccinations of females extended the duration of infertility far beyond the targeted management period, with time to first post-treatment parturition increasing 411days for every annual inoculation received. When these animals did conceive and give birth, parturition was later in the year and temporally asynchronous with forage abundance. An average of 30% (range=11–77%) of females were contracepted annually during the treatment period in all three populations and apparent annual population growth rate was 4–9% lower in the post-treatment years as compared to pretreatment years. Population growth was positive, however, and increased steadily every year that a management removal did not occur. The observed number of births was 33% fewer than the expected number of births, based on number of treated females, individual efficacy of treatment, and number of untreated females and their age-specific fecundity rates. Only half of this difference was explained by the apparent residual effect of treatment. Birth rate in the youngest untreated females (age 2–5 years old) was reduced in years when their conspecifics were treated, enhancing the effects of

Molecular Cloning, Characterization and Predicted Structure of a Putative Copper-Zinc SOD from the Camel, Camelus dromedarius

Directory of Open Access Journals (Sweden)

Ajamaluddin Malik

2012-01-01

Full Text Available Superoxide dismutase (SOD is the first line of defense against oxidative stress induced by endogenous and/or exogenous factors and thus helps in maintaining the cellular integrity. Its activity is related to many diseases; so, it is of importance to study the structure and expression of SOD gene in an animal naturally exposed most of its life to the direct sunlight as a cause of oxidative stress. Arabian camel (one humped camel, Camelus dromedarius is adapted to the widely varying desert climatic conditions that extremely changes during daily life in the Arabian Gulf. Studying the cSOD1 in C. dromedarius could help understand the impact of exposure to direct sunlight and desert life on the health status of such mammal. The full coding region of a putative CuZnSOD gene of C. dromedarius (cSOD1 was amplified by reverse transcription PCR and cloned for the first time (gene bank accession number for nucleotides and amino acids are JF758876 and AEF32527, respectively. The cDNA sequencing revealed an open reading frame of 459 nucleotides encoding a protein of 153 amino acids which is equal to the coding region of SOD1 gene and protein from many organisms. The calculated molecular weight and isoelectric point of cSOD1 was 15.7 kDa and 6.2, respectively. The level of expression of cSOD1 in different camel tissues (liver, kidney, spleen, lung and testis was examined using Real Time-PCR. The highest level of cSOD1 transcript was found in the camel liver (represented as 100% followed by testis (45%, kidney (13%, lung (11% and spleen (10%, using 18S ribosomal subunit as endogenous control. The deduced amino acid sequence exhibited high similarity with Cebus apella (90%, Sus scrofa (88%, Cavia porcellus (88%, Mus musculus (88%, Macaca mulatta (87%, Pan troglodytes (87%, Homo sapiens (87%, Canis familiaris (86%, Bos taurus (86%, Pongo abelii (85% and Equus caballus (82%. Phylogenetic analysis revealed that cSOD1 is grouped together with S. scrofa. The

Molecular cloning, characterization and predicted structure of a putative copper-zinc SOD from the camel, Camelus dromedarius.

Science.gov (United States)

Ataya, Farid S; Fouad, Dalia; Al-Olayan, Ebtsam; Malik, Ajamaluddin

2012-01-01

Superoxide dismutase (SOD) is the first line of defense against oxidative stress induced by endogenous and/or exogenous factors and thus helps in maintaining the cellular integrity. Its activity is related to many diseases; so, it is of importance to study the structure and expression of SOD gene in an animal naturally exposed most of its life to the direct sunlight as a cause of oxidative stress. Arabian camel (one humped camel, Camelus dromedarius) is adapted to the widely varying desert climatic conditions that extremely changes during daily life in the Arabian Gulf. Studying the cSOD1 in C. dromedarius could help understand the impact of exposure to direct sunlight and desert life on the health status of such mammal. The full coding region of a putative CuZnSOD gene of C. dromedarius (cSOD1) was amplified by reverse transcription PCR and cloned for the first time (gene bank accession number for nucleotides and amino acids are JF758876 and AEF32527, respectively). The cDNA sequencing revealed an open reading frame of 459 nucleotides encoding a protein of 153 amino acids which is equal to the coding region of SOD1 gene and protein from many organisms. The calculated molecular weight and isoelectric point of cSOD1 was 15.7 kDa and 6.2, respectively. The level of expression of cSOD1 in different camel tissues (liver, kidney, spleen, lung and testis) was examined using Real Time-PCR. The highest level of cSOD1 transcript was found in the camel liver (represented as 100%) followed by testis (45%), kidney (13%), lung (11%) and spleen (10%), using 18S ribosomal subunit as endogenous control. The deduced amino acid sequence exhibited high similarity with Cebus apella (90%), Sus scrofa (88%), Cavia porcellus (88%), Mus musculus (88%), Macaca mulatta (87%), Pan troglodytes (87%), Homo sapiens (87%), Canis familiaris (86%), Bos taurus (86%), Pongo abelii (85%) and Equus caballus (82%). Phylogenetic analysis revealed that cSOD1 is grouped together with S. scrofa. The

Experimental induction of equine protozoal myeloencephalitis in horses using Sarcocystis sp. sporocysts from the opossum (Didelphis virginiana).

Science.gov (United States)

Fenger, C K; Granstrom, D E; Gajadhar, A A; Williams, N M; McCrillis, S A; Stamper, S; Langemeier, J L; Dubey, J P

1997-02-01

Sarcocystis sp. sporocysts isolated from eight feral opossums (Didelphis virginiana) were pooled and fed to 18 commercially reared budgerigars (Melopsittacus undulatus), 14 wild-caught sparrows (Passer domesticus), one wild-caught slate-colored Junco (Junco hyemalis) and five weanling horses (Equus caballus). All budgerigars died within 5 weeks post inoculation (wpi). Histologic examination revealed meronts within the pulmonary epithelia and typical Sarcocystis falcatula sarcocysts developing in the leg muscles. Sparrows were euthanized 13 and 17 wpi and their carcasses were fed to four laboratory raised opossums. Sporocysts were detected in the feces of two opossums on 15 days post inoculation (dpi) and in a third opossum on 40 dpi. Fecal samples from the fourth opossum remained negative; however, sporocysts were found in intestinal digests from all four opossums. Sporocysts were not found in feces or intestinal digest of an additional opossum that was fed three uninoculated sparrows. Five foals were fed sporocysts (Foals 2, 3, 4, 5, and 7) and two foals were maintained as uninoculated controls (Foals 1 and 6). Sporocysts from two additional feral opossums also were fed to foals. Foal 5 was given 0.05 mg kg-1 dexamethasone sodium phosphate daily beginning 2 days before inoculation for a total of 2 weeks. Horse sera were tested three times per week, and cerebrospinal fluid (CSF) samples were tested biweekly for anti-Sarcocystis neurona antibodies by Western blot analysis. No foals had any S. neurona-specific antibodies by Western blot analysis prior to sporocysts ingestion. Seroconversion occurred in Foals 3, 5, and 7 by 24 dpi, followed by positive CSF tests on 28 dpi. Foals 2 and 4 seroconverted by 40 dpi. Cerebrospinal fluid from Foal 2 tested positive by 42 dpi, but Foal 4 remained seronegative throughout the study. Sera and CSF from control Foals 1 and 6 remained seronegative. All foals with positive CSF developed neurologic clinical signs. Neurologic disease

The electron

International Nuclear Information System (INIS)

Hestenes, David; Weingartshofer, Antonio

1991-01-01

The stupendous successes of the Dirac equation and quantum electro-dynamics have established the electron as the best understood of the fundamental constituents of matter. Nevertheless, physicists agree that the electron still has secrets to reveal. Moreover, powerful new theoretical and experimental tools for probing those secrets have been sharpened during the last decade. This workshop was organized to bring theorists and experimentalists together to discuss their common goal of knowing the electron. Present state and future prospects for progress toward that goal are here described. The theoretical papers encompass a wide range of views on the electron. Several argue that the 'Zitter-bewegung' is more than a mathematical peculiarity of the Dirac equation, that it may well be a real physical phenomenon and worthy of serious study, theoretically and experimentally. Besides generating the electron spin and magnetic moment, the 'Zitterbewegung' may be a vital clue to electron structure and self-interaction. Some of the papers employ a radical new formulation of the Dirac theory which reveals a hidden geo-metric structure in the theory that supports a 'Zitterbewegung' inter-pretation. For the last half century the properties of electrons have been probed primarily by scattering experiments at ever higher energies. Recently, however, two powerful new experimental techniques have emerged capable of giving alternative experimental views of the electron. First, techniques for confining single electrons for long term study have led to the most accurate measurements of the electron magnetic moment. Second, the interaction of high intensity laser fields with atoms and electrons have revealed striking new phenomena such as multiphoton ionization. refs.; figs.; tabs

Basic electronics

CERN Document Server

Holbrook, Harold D

1971-01-01

Basic Electronics is an elementary text designed for basic instruction in electricity and electronics. It gives emphasis on electronic emission and the vacuum tube and shows transistor circuits in parallel with electron tube circuits. This book also demonstrates how the transistor merely replaces the tube, with proper change of circuit constants as required. Many problems are presented at the end of each chapter. This book is comprised of 17 chapters and opens with an overview of electron theory, followed by a discussion on resistance, inductance, and capacitance, along with their effects on t

Electron-electron scattering and mobilities in semiconductors and quantum wells

International Nuclear Information System (INIS)

Lyo, S.K.

1986-01-01

The effect of electron-electron scattering on the mobility in semiconductors and semiconductor quantum wells is examined. A general exact formula is derived for the mobility, when the electron-electron collision rate is much faster than other scattering rates such as those by ionized impurities and phonons. In this limit, the transport relaxation rate is independent of the carrier's energy and contributions to the inverse mobility from individual scattering mechanism add up. The mobility becomes significantly reduced from its value in the absence of electron-electron scattering. When the collision rates are not necessarily dominated by electron-electron scattering, the mobility is calculated by the Kohler-Sondheimer variational method in the presence of ionized-impurity scattering and acoustic-phonon scattering in a nondegenerate two-dimensional quantum well

Modified Monte Carlo method for study of electron transport in degenerate electron gas in the presence of electron-electron interactions, application to graphene

Science.gov (United States)

Borowik, Piotr; Thobel, Jean-Luc; Adamowicz, Leszek

2017-07-01

Standard computational methods used to take account of the Pauli Exclusion Principle into Monte Carlo (MC) simulations of electron transport in semiconductors may give unphysical results in low field regime, where obtained electron distribution function takes values exceeding unity. Modified algorithms were already proposed and allow to correctly account for electron scattering on phonons or impurities. Present paper extends this approach and proposes improved simulation scheme allowing including Pauli exclusion principle for electron-electron (e-e) scattering into MC simulations. Simulations with significantly reduced computational cost recreate correct values of the electron distribution function. Proposed algorithm is applied to study transport properties of degenerate electrons in graphene with e-e interactions. This required adapting the treatment of e-e scattering in the case of linear band dispersion relation. Hence, this part of the simulation algorithm is described in details.

Attainment of Electron Beam Suitable for Medium Energy Electron Cooling

Energy Technology Data Exchange (ETDEWEB)

Seletskiy, Sergei M. [Univ. of Rochester, NY (United States)

2005-01-01

Electron cooling of charged particle beams is a well-established technique at electron energies of up to 300 keV. However, up to the present time the advance of electron cooling to the MeV-range energies has remained a purely theoretical possibility. The electron cooling project at Fermilab has recently demonstrated the ¯rst cooling of 8.9 GeV/c antiprotons in the Recycler ring, and therefore, has proved the validity of the idea of relativistic electron cool- ing. The Recycler Electron Cooler (REC) is the key component of the Teva- tron Run II luminosity upgrade project. Its performance depends critically on the quality of electron beam. A stable electron beam of 4.3 MeV car- rying 0.5 A of DC current is required. The beam suitable for the Recycler Electron Cooler must have an angular spread not exceeding 200 ¹rad. The full-scale prototype of the REC was designed, built and tested at Fermilab in the Wideband laboratory to study the feasibility of attaining the high-quality electron beam. In this thesis I describe various aspects of development of the Fermilab electron cooling system, and the techniques used to obtain the electron beam suitable for the cooling process. In particular I emphasize those aspects of the work for which I was principally responsible.

Microfluidic electronics.

Science.gov (United States)

Cheng, Shi; Wu, Zhigang

2012-08-21

Microfluidics, a field that has been well-established for several decades, has seen extensive applications in the areas of biology, chemistry, and medicine. However, it might be very hard to imagine how such soft microfluidic devices would be used in other areas, such as electronics, in which stiff, solid metals, insulators, and semiconductors have previously dominated. Very recently, things have radically changed. Taking advantage of native properties of microfluidics, advances in microfluidics-based electronics have shown great potential in numerous new appealing applications, e.g. bio-inspired devices, body-worn healthcare and medical sensing systems, and ergonomic units, in which conventional rigid, bulky electronics are facing insurmountable obstacles to fulfil the demand on comfortable user experience. Not only would the birth of microfluidic electronics contribute to both the microfluidics and electronics fields, but it may also shape the future of our daily life. Nevertheless, microfluidic electronics are still at a very early stage, and significant efforts in research and development are needed to advance this emerging field. The intention of this article is to review recent research outcomes in the field of microfluidic electronics, and address current technical challenges and issues. The outlook of future development in microfluidic electronic devices and systems, as well as new fabrication techniques, is also discussed. Moreover, the authors would like to inspire both the microfluidics and electronics communities to further exploit this newly-established field.

Electron-electron collision effects on the bremsstrahlung emission in Lorentzian plasmas

International Nuclear Information System (INIS)

Jung, Young-Dae; Kato, Daiji

2009-01-01

Electron-electron collision effects on the electron-ion bremsstrahlung process are investigated in Lorentzian plasmas. The effective electron-ion interaction potential is obtained by including the far-field terms caused by electron-electron collisions with an effective Debye length in Lorentzian plasmas. The bremsstrahlung radiation cross section is obtained as a function of the electron energy, photon energy, collision frequency, spectral index and Debye length using the Born approximation for the initial and final states of the projectile electron. It is shown that the non-Maxwellian character suppresses the bremsstrahlung radiation cross section. It is also shown that the electron-electron collision effect enhances the bremsstrahlung emission spectrum. In addition, the bremsstrahlung radiation cross section decreases with an increase in the plasma temperature.

Electron-photon and electron-electron interactions in the presence of strong electromagnetic fields

International Nuclear Information System (INIS)

Surzhykov, A.; Fritzsche, S.; Stoehlker, Th.

2010-01-01

During the last decade, photon emission from highly-charged, heavy ions has been in the focus of intense studies at the GSI accelerator and storage ring facility in Darmstadt. These studies have revealed unique information about the electron-electron and electron-photon interactions in the presence of extremely strong nuclear fields. Apart from the radiative electron capture processes, characteristic photon emission following collisional excitation of projectile ions has also attracted much interest. In this contribution, we summarize the recent theoretical studies on the production of excited ionic states and their subsequent radiative decay. We will pay special attention to the angular and polarization properties of Kα emission from helium-like ions produced by means of dielectronic recombination. The results obtained for this (resonant) capture process will be compared with the theoretical predictions for the characteristic X-rays following Coulomb excitation and radiative recombination of few-electron, heavy ions. Work is supported by Helmholtz Association and GSl under the project VH-NG--421. (author)

Sticker electronics

KAUST Repository

Hussain, Muhammad Mustafa

2017-09-08

Electronic stickers may be manufactured on flexible substrates (110, 120, 130) as layers and packaged together. The package may then have an adhesive applied to one side to provide capability for sticking the electronic devices to surfaces. The stickers can be wrappable, placed on surfaces, glued on walls or mirrors or wood or stone, and have electronics (112, 122, 132) which may or may not be ultrathin. Packaging for the electronic sticker can use polymer on cellulose manufacturing and/or three dimensional (3-D) printing. The electronic stickers may provide lighting capability, sensing capability, and/or recharging capabilities.

Electronic Commerce

Directory of Open Access Journals (Sweden)

Slavko Đerić

2016-12-01

Full Text Available Electronic commerce can be defined in different ways. Any definition helps to understand and explain that concept as better as possible.. Electronic commerce is a set of procedures and technologies that automate the tasks of financial transactions using electronic means. Also, according to some authors, electronic commerce is defined as a new concept, which is being developed and which includes process of buying and selling or exchanging products, services or information via computer networks, including the Internet. Electronic commerce is not limited just to buying and selling, but it also includes all pre-sales and after-sales ongoing activities along the supply chain. Introducing electronic commerce, using the Internet and Web services in business, realizes the way to a completely new type of economy - internet economy.

Observation of the two-electron cusp in atomic collisions. Evidence for strong electron-electron correlation

International Nuclear Information System (INIS)

Sarkadi, L.; Orban, A.

2007-01-01

Complete text of publication follows. In this report we present experimental data for a process when two electrons with velocity vectors equal to that of the projectile are emitted from collisions. By observing the two electron cusp the study of the threshold phenomenon for two-electron break-up is possible. It is a particularly interesting question whether the outgoing charged projectile can attract the two repulsing electrons so strongly that the two-electron cusp is formed. If it is so, a further question arises: Are the two electrons correlated in the final state as it is predicted by the Wannier theory? The experiments have been done at the 1 MeV VdG accelerator of ATOMKI using our TOF spectrometer. The first measurements clearly showed the formation of the two-electron cusp and signature of the electron correlation in 200 keV He 0 +He collisions. These promising results motivated us to carry out the experiment at 100 keV beam energy where the coincidence count rate is still reasonable but the energy resolution is better. For an acceptable data acquisition time we improved our data acquisition and data processing system for triple coincidence measurements. In Fig. 1a we present our measured relative fourfold differential cross section (FDCS) that shows strong electron correlation. For a comparison, in Fig. 1b we displayed the contour plot for uncorrelated electron pair emission. These latter data were synthesized artificially, generating the energies of the electron pairs from two independent double coincidence experiments. In both figures the distributions are characterized by two ridges. In Fig. 1b the ridges are perpendicular straight lines (E 1 = E 2 .13.6 eV). As a result of the correlation, the ridges in Fig. 1a are distorted in such a way that they have a joint straight-line section following the line E 1 + E 2 = 27.2 eV. This means that the electron pairs in the vicinity of the cusp maximum are emitted with a center of- mass velocity equal to that of

Electronics and Information

Institute of Scientific and Technical Information of China (English)

无

2008-01-01

@@ Previously founded as CCPITMachinery and Electronics Sub-council and CCOIC Machinery and Electronics Chamber of Corn-merce in June, 1988, CCPIT Electronics Sub-Council and CCOIC Electronics Chamber of Commerce were established in May, 1993, and then renamed as CCPIT Electronics and Information Industry Sub-council and CCOIC Electronics and Infor-mation Industry Chamber of Commerce (CCPITECC) in September 1999.

Spontaneous and stimulated emission induced by an electron, electron bunch, and electron beam in a plasma

International Nuclear Information System (INIS)

Kuzelev, M V; Rukhadze, A A

2008-01-01

Two fundamental mechanisms - the Cherenkov effect and anomalous Doppler effect - underlying the emission by an electron during its superluminal motion in medium are considered. Cherenkov emission induced by a single electron and a small electron bunch is spontaneous. In the course of spontaneous Cherenkov emission, the translational motion of an electron is slowed down and the radiation energy grows linearly with time. As the number of radiating electrons increases, Cherenkov emission becomes stimulated. Stimulated Cherenkov emission represents a resonance beam instability. This emission process is accompanied by longitudinal electron bunching in the beam or by the breaking of an electron bunch into smaller bunches, in which case the radiation energy grows exponentially with time. In terms of the longitudinal size L e of the electron bunch there is a transition region λ e 0 -1 between the spontaneous and stimulated Cherenkov effects, where λ is the average radiation wavelength, and δ 0 is the dimensionless (in units of the radiation frequency) growth rate of the Cherenkov beam instability. The range to the left of this region is dominated by spontaneous emission, whereas the range to the right of this region is dominated by stimulated emission. In contrast to the Vavilov-Cherenkov effect, the anomalous Doppler effect should always (even for a single electron) be considered as stimulated, because it can only be explained by accounting for the reverse action of the radiation field on the moving electron. During stimulated emission in conditions where anomalous Doppler effect shows itself, an electron is slowed down and spins up; in this case, the radiation energy grows exponentially with time. (reviews of topical problems)

High perveance electron gun for the electron cooling system

International Nuclear Information System (INIS)

Korotaev, Yu.; Meshkov, I.; Petrov, A.; Sidorin, A.; Smirnov, A.; Syresin, E.; Titkova, I.

2000-01-01

The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 μA/V 3/2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual)

High perveance electron gun for the electron cooling system

CERN Document Server

Korotaev, Yu V; Petrov, A; Sidorin, A; Smirnov, A; Syresin, E M; Titkova, I

2000-01-01

The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 mu A/V sup 3 sup / sup 2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual).

Study of single-electron excitations by electron microscopy

International Nuclear Information System (INIS)

Craven, A.J.; Gibson, J.M.; Howie, A.; Spalding, D.R.

1978-01-01

The inelastic scattering of fast electrons by the excitation of L-shell electrons at a stacking fault in silicon has been studied with a scanning transmission electron microscope. It was found that the bright-field stacking fault contrast is preserved in the filtered L-shell-loss signal at 100 eV. This result is discussed in terms of the delocalization of the excitation mechanism. It is concluded that localization effects will typically become significant only for energy transfers greater than 1 keV from a fast electron of energy 80 keV. (author)

Syringe injectable electronics

Science.gov (United States)

Hong, Guosong; Zhou, Tao; Jin, Lihua; Duvvuri, Madhavi; Jiang, Zhe; Kruskal, Peter; Xie, Chong; Suo, Zhigang; Fang, Ying; Lieber, Charles M.

2015-01-01

Seamless and minimally-invasive three-dimensional (3D) interpenetration of electronics within artificial or natural structures could allow for continuous monitoring and manipulation of their properties. Flexible electronics provide a means for conforming electronics to non-planar surfaces, yet targeted delivery of flexible electronics to internal regions remains difficult. Here, we overcome this challenge by demonstrating syringe injection and subsequent unfolding of submicrometer-thick, centimeter-scale macroporous mesh electronics through needles with a diameter as small as 100 micrometers. Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with > 90% device yield. We demonstrate several applications of syringe injectable electronics as a general approach for interpenetrating flexible electronics with 3D structures, including (i) monitoring of internal mechanical strains in polymer cavities, (ii) tight integration and low chronic immunoreactivity with several distinct regions of the brain, and (iii) in vivo multiplexed neural recording. Moreover, syringe injection enables delivery of flexible electronics through a rigid shell, delivery of large volume flexible electronics that can fill internal cavities and co-injection of electronics with other materials into host structures, opening up unique applications for flexible electronics. PMID:26053995

Electronic Nose and Electronic Tongue

Science.gov (United States)

Bhattacharyya, Nabarun; Bandhopadhyay, Rajib

Human beings have five senses, namely, vision, hearing, touch, smell and taste. The sensors for vision, hearing and touch have been developed for several years. The need for sensors capable of mimicking the senses of smell and taste have been felt only recently in food industry, environmental monitoring and several industrial applications. In the ever-widening horizon of frontier research in the field of electronics and advanced computing, emergence of electronic nose (E-Nose) and electronic tongue (E-Tongue) have been drawing attention of scientists and technologists for more than a decade. By intelligent integration of multitudes of technologies like chemometrics, microelectronics and advanced soft computing, human olfaction has been successfully mimicked by such new techniques called machine olfaction (Pearce et al. 2002). But the very essence of such research and development efforts has centered on development of customized electronic nose and electronic tongue solutions specific to individual applications. In fact, research trends as of date clearly points to the fact that a machine olfaction system as versatile, universal and broadband as human nose and human tongue may not be feasible in the decades to come. But application specific solutions may definitely be demonstrated and commercialized by modulation in sensor design and fine-tuning the soft computing solutions. This chapter deals with theory, developments of E-Nose and E-Tongue technology and their applications. Also a succinct account of future trends of R&D efforts in this field with an objective of establishing co-relation between machine olfaction and human perception has been included.

A theory of electron baths: One-electron system dynamics

International Nuclear Information System (INIS)

McDowell, H.K.

1992-01-01

The second-quantized, many-electron, atomic, and molecular Hamiltonian is partitioned both by the identity or labeling of the spin orbitals and by the dynamics of the spin orbitals into a system coupled to a bath. The electron bath is treated by a molecular time scale generalized Langevin equation approach designed to include one-electron dynamics in the system dynamics. The bath is formulated as an equivalent chain of spin orbitals through the introduction of equivalent-chain annihilation and creation operators. Both the dynamics and the quantum grand canonical statistical properties of the electron bath are examined. Two versions for the statistical properties of the bath are pursued. Using a weak bath assumption, a bath statistical average is defined which allows one to achieve a reduced dynamics description of the electron system which is coupled to the electron bath. In a strong bath assumption effective Hamiltonians are obtained which reproduce the dynamics of the bath and which lead to the same results as found in the weak bath assumption. The effective (but exact) Hamiltonian is found to be a one-electron Hamiltonian. A reduced dynamics equation of motion for the system population matrix is derived and found to agree with a previous version. This equation of motion is useful for studying electron transfer in the system when coupled to an electron bath

Treatment of foods with 'soft-electrons' (low-energy electrons)

International Nuclear Information System (INIS)

Hayashi, Toru; Todoriki, Setsuko

2003-01-01

Electrons with energies of 300 keV or lower were defined as soft-electrons'. Soft-electrons can eradicate microorganisms residing on the surface of grains, pulses, spices, dehydrated vegetables, tea leaves and seeds, and reduce their microbial loads to levels lower than 10 CFU/g with little quality deterioration. Soft-electrons can inactivate insect pests infesting grains and pulses and inhibit sprouting of potatoes. (author)

Compact femtosecond electron diffractometer with 100 keV electron bunches approaching the single-electron pulse duration limit

International Nuclear Information System (INIS)

Waldecker, Lutz; Bertoni, Roman; Ernstorfer, Ralph

2015-01-01

We present the design and implementation of a highly compact femtosecond electron diffractometer working at electron energies up to 100 keV. We use a multi-body particle tracing code to simulate electron bunch propagation through the setup and to calculate pulse durations at the sample position. Our simulations show that electron bunches containing few thousands of electrons per bunch are only weakly broadened by space-charge effects and their pulse duration is thus close to the one of a single-electron wavepacket. With our compact setup, we can create electron bunches containing up to 5000 electrons with a pulse duration below 100 fs on the sample. We use the diffractometer to track the energy transfer from photoexcited electrons to the lattice in a thin film of titanium. This process takes place on the timescale of few-hundred femtoseconds and a fully equilibrated state is reached within 1 ps

Electron backscattering for process control in electron beam welding

International Nuclear Information System (INIS)

Ardenne, T. von; Panzer, S.

1983-01-01

A number of solutions to the automation of electron beam welding is presented. On the basis of electron backscattering a complex system of process control has been developed. It allows an enlarged imaging of the material's surface, improved adjustment of the beam focusing and definite focus positioning. Furthermore, both manual and automated positioning of the electron beam before and during the welding process has become possible. Monitoring of the welding process for meeting standard welding requirements can be achieved with the aid of a control quantity derived from the results of electronic evaluation of the high-frequency electron backscattering

Electron transfer reactions

CERN Document Server

Cannon, R D

2013-01-01

Electron Transfer Reactions deals with the mechanisms of electron transfer reactions between metal ions in solution, as well as the electron exchange between atoms or molecules in either the gaseous or solid state. The book is divided into three parts. Part 1 covers the electron transfer between atoms and molecules in the gas state. Part 2 tackles the reaction paths of oxidation states and binuclear intermediates, as well as the mechanisms of electron transfer. Part 3 discusses the theories and models of the electron transfer process; theories and experiments involving bridged electron transfe

Understand electronics

CERN Document Server

Bishop, Owen

2013-01-01

Understand Electronics provides a readable introduction to the exciting world of electronics for the student or enthusiast with little previous knowledge. The subject is treated with the minimum of mathematics and the book is extensively illustrated.This is an essential guide for the newcomer to electronics, and replaces the author's best-selling Beginner's Guide to Electronics.The step-by-step approach makes this book ideal for introductory courses such as the Intermediate GNVQ.

Electronic Commerce

OpenAIRE

Slavko Đerić

2016-01-01

Electronic commerce can be defined in different ways. Any definition helps to understand and explain that concept as better as possible.. Electronic commerce is a set of procedures and technologies that automate the tasks of financial transactions using electronic means. Also, according to some authors, electronic commerce is defined as a new concept, which is being developed and which includes process of buying and selling or exchanging products, services or information via computer networks...

Photon and electron collimator effects on electron output and abutting segments in energy modulated electron therapy

International Nuclear Information System (INIS)

Olofsson, Lennart; Karlsson, Magnus G.; Karlsson, Mikael

2005-01-01

In energy modulated electron therapy a large fraction of the segments will be arranged as abutting segments where inhomogeneities in segment matching regions must be kept as small as possible. Furthermore, the output variation between different segments should be minimized and must in all cases be well predicted. For electron therapy with add-on collimators, both the electron MLC (eMLC) and the photon MLC (xMLC) contribute to these effects when an xMLC tracking technique is utilized to reduce the x-ray induced leakage. Two add-on electron collimator geometries have been analyzed using Monte Carlo simulations: One isocentric eMLC geometry with an isocentric clearance of 35 cm and air or helium in the treatment head, and one conventional proximity geometry with a clearance of 5 cm and air in the treatment head. The electron fluence output for 22.5 MeV electrons is not significantly affected by the xMLC if the shielding margins are larger than 2-3 cm. For small field sizes and 9.6 MeV electrons, the isocentric design with helium in the treatment head or shielding margins larger than 3 cm is needed to avoid a reduced electron output. Dose inhomogeneity in the matching region of electron segments is, in general, small when collimator positions are adjusted to account for divergence in the field. The effect of xMLC tracking on the electron output can be made negligible while still obtaining a substantially reduced x-ray leakage contribution. Collimator scattering effects do not interfere significantly when abutting beam techniques are properly applied

Equation satisfied by electron-electron mutual Coulomb repulsion energy density functional

OpenAIRE

Joubert, Daniel P.

2011-01-01

The electron-electron mutual Coulomb repulsion energy density functional satisfies an equation that links functionals and functional derivatives at N-electron and (N-1)-electron densities for densities determined from the same adiabatic scaled external potential for the N-electron system.

Electronic Publishing.

Science.gov (United States)

Lancaster, F. W.

1989-01-01

Describes various stages involved in the applications of electronic media to the publishing industry. Highlights include computer typesetting, or photocomposition; machine-readable databases; the distribution of publications in electronic form; computer conferencing and electronic mail; collaborative authorship; hypertext; hypermedia publications;…

Syringe-injectable electronics.

Science.gov (United States)

Liu, Jia; Fu, Tian-Ming; Cheng, Zengguang; Hong, Guosong; Zhou, Tao; Jin, Lihua; Duvvuri, Madhavi; Jiang, Zhe; Kruskal, Peter; Xie, Chong; Suo, Zhigang; Fang, Ying; Lieber, Charles M

2015-07-01

Seamless and minimally invasive three-dimensional interpenetration of electronics within artificial or natural structures could allow for continuous monitoring and manipulation of their properties. Flexible electronics provide a means for conforming electronics to non-planar surfaces, yet targeted delivery of flexible electronics to internal regions remains difficult. Here, we overcome this challenge by demonstrating the syringe injection (and subsequent unfolding) of sub-micrometre-thick, centimetre-scale macroporous mesh electronics through needles with a diameter as small as 100 μm. Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with >90% device yield. We demonstrate several applications of syringe-injectable electronics as a general approach for interpenetrating flexible electronics with three-dimensional structures, including (1) monitoring internal mechanical strains in polymer cavities, (2) tight integration and low chronic immunoreactivity with several distinct regions of the brain, and (3) in vivo multiplexed neural recording. Moreover, syringe injection enables the delivery of flexible electronics through a rigid shell, the delivery of large-volume flexible electronics that can fill internal cavities, and co-injection of electronics with other materials into host structures, opening up unique applications for flexible electronics.

Electronic excitation of Na atom by electron impact

International Nuclear Information System (INIS)

Bielschowsky, C.E.; Souza, G.G.B. de; Lucas, C.A.; Nogueira, J.C.

1988-01-01

Electronic excitation of the 3s-3p transition in the Na atom was studied by intermediate energy electron impact spectroscopy. Differential Cross Sections (DCS) and Generalized Oscillator Strenghts (GOS) were determined experimentally for 1 KeV electrons. Theoretical results within the First Born Approximation as well as Glauber theory, were also performed. (A.C.A.S.) [pt

Highly efficient electron gun with a single-atom electron source

International Nuclear Information System (INIS)

Ishikawa, Tsuyoshi; Urata, Tomohiro; Cho, Boklae; Rokuta, Eiji; Oshima, Chuhei; Terui, Yoshinori; Saito, Hidekazu; Yonezawa, Akira; Tsong, Tien T.

2007-01-01

The authors have demonstrated highly collimated electron-beam emission from a practical electron gun with a single-atom electron source; ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources such as a cold field emission gun and a Zr/O/W Schottky gun. At the pressure of less than 1x10 -9 Pa, the authors observed stable emission of 20 nA, which generates the specimen current of 5 pA required for scanning electron microscopes

Electron-electron interaction in p-SiGe/Ge quantum wells

International Nuclear Information System (INIS)

Roessner, Benjamin; Kaenel, Hans von; Chrastina, Daniel; Isella, Giovanni; Batlogg, Bertram

2005-01-01

The temperature dependent magnetoresistance of high mobility p-SiGe/Ge quantum wells is studied with hole densities ranging from 1.7 to 5.9 x 10 11 cm -2 . At magnetic fields below the onset of quantum oscillations that reflect the high mobility values (up to 75000 cm 2 /Vs), we observe the clear signatures of electron-electron interaction. We compare our experiment with the theory of electron-electron interaction including the Zeeman band splitting. The observed magnetoresistance is well explained as a superposition of band structure induced positive magnetoresistance and the negative magntoresistance due to the electron-electron interaction effect

Detecting taxonomic and phylogenetic signals in equid cheek teeth: towards new palaeontological and archaeological proxies

Science.gov (United States)

Mohaseb, A.; Peigné, S.; Debue, K.; Orlando, L.; Mashkour, M.

2017-01-01

The Plio–Pleistocene evolution of Equus and the subsequent domestication of horses and donkeys remains poorly understood, due to the lack of phenotypic markers capable of tracing this evolutionary process in the palaeontological/archaeological record. Using images from 345 specimens, encompassing 15 extant taxa of equids, we quantified the occlusal enamel folding pattern in four mandibular cheek teeth with a single geometric morphometric protocol. We initially investigated the protocol accuracy by assigning each tooth to its correct anatomical position and taxonomic group. We then contrasted the phylogenetic signal present in each tooth shape with an exome-wide phylogeny from 10 extant equine species. We estimated the strength of the phylogenetic signal using a Brownian motion model of evolution with multivariate K statistic, and mapped the dental shape along the molecular phylogeny using an approach based on squared-change parsimony. We found clear evidence for the relevance of dental phenotypes to accurately discriminate all modern members of the genus Equus and capture their phylogenetic relationships. These results are valuable for both palaeontologists and zooarchaeologists exploring the spatial and temporal dynamics of the evolutionary history of the horse family, up to the latest domestication trajectories of horses and donkeys. PMID:28484618

Electron-electron interactions in disordered systems

CERN Document Server

Efros, AL

1985-01-01

``Electron-Electron Interactions in Disordered Systems'' deals with the interplay of disorder and the Coulomb interaction. Prominent experts give state-of-the-art reviews of the theoretical and experimental work in this field and make it clear that the interplay of the two effects is essential, especially in low-dimensional systems.

Narrow electron injector for ballistic electron spectroscopy

International Nuclear Information System (INIS)

Kast, M.; Pacher, C.; Strasser, G.; Gornik, E.

2001-01-01

A three-terminal hot electron transistor is used to measure the normal energy distribution of ballistic electrons generated by an electron injector utilizing an improved injector design. A triple barrier resonant tunneling diode with a rectangular transmission function acts as a narrow (1 meV) energy filter. An asymmetric energy distribution with its maximum on the high-energy side with a full width at half maximum of ΔE inj =10 meV is derived. [copyright] 2001 American Institute of Physics

Temperature Dependence of the Spin-Hall Conductivity of a Two-Dimensional Impure Rashba Electron Gas in the Presence of Electron-Phonon and Electron-Electron Interactions

Science.gov (United States)

Yavari, H.; Mokhtari, M.; Bayervand, A.

2015-03-01

Based on Kubo's linear response formalism, temperature dependence of the spin-Hall conductivity of a two-dimensional impure (magnetic and nonmagnetic impurities) Rashba electron gas in the presence of electron-electron and electron-phonon interactions is analyzed theoretically. We will show that the temperature dependence of the spin-Hall conductivity is determined by the relaxation rates due to these interactions. At low temperature, the elastic lifetimes ( and are determined by magnetic and nonmagnetic impurity concentrations which are independent of the temperature, while the inelastic lifetimes ( and related to the electron-electron and electron-phonon interactions, decrease when the temperature increases. We will also show that since the spin-Hall conductivity is sensitive to temperature, we can distinguish the intrinsic and extrinsic contributions.

Analytical local electron-electron interaction model potentials for atoms

International Nuclear Information System (INIS)

Neugebauer, Johannes; Reiher, Markus; Hinze, Juergen

2002-01-01

Analytical local potentials for modeling the electron-electron interaction in an atom reduce significantly the computational effort in electronic structure calculations. The development of such potentials has a long history, but some promising ideas have not yet been taken into account for further improvements. We determine a local electron-electron interaction potential akin to those suggested by Green et al. [Phys. Rev. 184, 1 (1969)], which are widely used in atom-ion scattering calculations, electron-capture processes, and electronic structure calculations. Generalized Yukawa-type model potentials are introduced. This leads, however, to shell-dependent local potentials, because the origin behavior of such potentials is different for different shells as has been explicated analytically [J. Neugebauer, M. Reiher, and J. Hinze, Phys. Rev. A 65, 032518 (2002)]. It is found that the parameters that characterize these local potentials can be interpolated and extrapolated reliably for different nuclear charges and different numbers of electrons. The analytical behavior of the corresponding localized Hartree-Fock potentials at the origin and at long distances is utilized in order to reduce the number of fit parameters. It turns out that the shell-dependent form of Green's potential, which we also derive, yields results of comparable accuracy using only one shell-dependent parameter

Extracting electron backscattering coefficients from backscattered electron micrographs

International Nuclear Information System (INIS)

Zupanic, F.

2010-01-01

Electron backscattering micrographs possess the so-called Z-contrast, carrying information about the chemical compositions of phases present in microstructures. The intensity at a particular point in the backscattered electron micrograph is proportional to the signal detected at a corresponding point in the scan raster, which is, in turn, proportional to the electron backscattering coefficient of a phase at that point. This article introduces a simple method for extracting the electron backscattering coefficients of phases present in the microstructure, from the backscattered electron micrographs. This method is able to convert the micrograph's greyscale to the backscattering-coefficient-scale. The prerequisite involves the known backscattering coefficients for two phases in the micrograph. In this way, backscattering coefficients of other phases can be determined. The method is unable to determine the chemical compositions of phases or the presence of an element only from analysing the backscattered electron micrograph. Nevertheless, this method was found to be very powerful when combined with energy dispersive spectroscopy, and the calculations of backscattering coefficients. - Research Highlights: →A simple method for extracting the electron backscattering coefficients →The prerequisite is known backscattering coefficients for two phases →The information is complementary to the EDS-results. →This method is especially useful when a phase contains a light element (H, Li, Be, and B)

PIC simulation of the electron-ion collision effects on suprathermal electrons

International Nuclear Information System (INIS)

Wu Yanqing; Han Shensheng

2000-01-01

The generation and transportation of suprathermal electrons are important to both traditional ICF scheme and 'Fast Ignition' scheme. The author discusses the effects of electron-ion collision on the generation and transportation of the suprathermal electrons by parametric instability. It indicates that the weak electron-ion term in the PIC simulation results in the enhancement of the collisional absorption and increase of the hot electron temperature and reduction in the maximum electrostatic field amplitude while wave breaking. Therefore the energy and distribution of the suprathermal electrons are changed. They are distributed more close to the phase velocity of the electrostatic wave than the case without electron-ion collision term. The electron-ion collision enhances the self-consistent field and impedes the suprathermal electron transportation. These factors also reduce the suprathermal electron energy. In addition, the authors discuss the effect of initial condition on PIC simulation to ensure that the results are correct

Spin Relaxation in GaAs: Importance of Electron-Electron Interactions

Directory of Open Access Journals (Sweden)

Gionni Marchetti

2014-04-01

Full Text Available We study spin relaxation in n-type bulk GaAs, due to the Dyakonov–Perel mechanism, using ensemble Monte Carlo methods. Our results confirm that spin relaxation time increases with the electronic density in the regime of moderate electronic concentrations and high temperature. We show that the electron-electron scattering in the non-degenerate regime significantly slows down spin relaxation. This result supports predictions by Glazov and Ivchenko. Most importantly, our findings highlight the importance of many-body interactions for spin dynamics: we show that only by properly taking into account electron-electron interactions within the simulations, results for the spin relaxation time—with respect to both electron density and temperature—will reach good quantitative agreement with corresponding experimental data. Our calculations contain no fitting parameters.

Secondary mineralization in carious lesions of human dentin. Electron-probe, electron microscope, and electron diffraction studies

Energy Technology Data Exchange (ETDEWEB)

Ogiwara, H [Tokyo Dental Coll. (Japan)

1975-02-01

Dentinal carious lesions having a remineralized surface layer were studied by means electron-probe microanalysis, electron microscopy, electron diffraction. As the results of electron-probe study, F, Mg, and Na were found to be distributed mainly in the remineralized surface layer and S in the decalcified region where decreases in Ca, P, and Mg concentration were usually observed. The decrease in Mg concentration always started earlier than that of Ca and P concentration. Electron microscope and electron diffraction studies revealed that apatic crystals in the remineralized surface layer were much larger than those in the intact dentin. Although they were less conspicuous, crystals in the decalcified region also were larger than those in the intact region. Dentinal tubules, occluded by many crystals, were frequently seen during the observations. Crystals in the tubules varied in morphology, showing granular, needle, rhomboid, and tabular shapes. By means of electron diffraction, the granular- or needle-shaped crystals were identified as apatite and the rhomboid-shaped crystals as whitlockite. Some of the tabular-shaped crystals appeared to be cotacalcium phosphate.

Electronic components

CERN Document Server

Colwell, Morris A

1976-01-01

Electronic Components provides a basic grounding in the practical aspects of using and selecting electronics components. The book describes the basic requirements needed to start practical work on electronic equipment, resistors and potentiometers, capacitance, and inductors and transformers. The text discusses semiconductor devices such as diodes, thyristors and triacs, transistors and heat sinks, logic and linear integrated circuits (I.C.s) and electromechanical devices. Common abbreviations applied to components are provided. Constructors and electronics engineers will find the book useful

Ion- and electron-acoustic solitons in two-electron temperature space plasmas

International Nuclear Information System (INIS)

Lakhina, G. S.; Kakad, A. P.; Singh, S. V.; Verheest, F.

2008-01-01

Properties of ion- and electron-acoustic solitons are investigated in an unmagnetized multicomponent plasma system consisting of cold and hot electrons and hot ions using the Sagdeev pseudopotential technique. The analysis is based on fluid equations and the Poisson equation. Solitary wave solutions are found when the Mach numbers exceed some critical values. The critical Mach numbers for the ion-acoustic solitons are found to be smaller than those for electron-acoustic solitons for a given set of plasma parameters. The critical Mach numbers of ion-acoustic solitons increase with the increase of hot electron temperature and the decrease of cold electron density. On the other hand, the critical Mach numbers of electron-acoustic solitons increase with the increase of the cold electron density as well as the hot electron temperature. The ion-acoustic solitons have positive potentials for the parameters considered. However, the electron-acoustic solitons have positive or negative potentials depending whether the fractional cold electron density with respect to the ion density is greater or less than a certain critical value. Further, the amplitudes of both the ion- and electron-acoustic solitons increase with the increase of the hot electron temperature. Possible application of this model to electrostatic solitary waves observed on the auroral field lines by the Viking spacecraft is discussed

Diffusive scattering of electrons by electron holes around injection fronts

Science.gov (United States)

Vasko, I. Y.; Agapitov, O. V.; Mozer, F. S.; Artemyev, A. V.; Krasnoselskikh, V. V.; Bonnell, J. W.

2017-03-01

Van Allen Probes have detected nonlinear electrostatic spikes around injection fronts in the outer radiation belt. These spikes include electron holes (EH), double layers, and more complicated solitary waves. We show that EHs can efficiently scatter electrons due to their substantial transverse electric fields. Although the electron scattering driven by EHs is diffusive, it cannot be evaluated via the standard quasi-linear theory. We derive analytical formulas describing local electron scattering by a single EH and verify them via test particle simulations. We show that the most efficiently scattered are gyroresonant electrons (crossing EH on a time scale comparable to the local electron gyroperiod). We compute bounce-averaged diffusion coefficients and demonstrate their dependence on the EH spatial distribution (latitudinal extent and spatial filling factor) and individual EH parameters (amplitude of electrostatic potential, velocity, and spatial scales). We show that EHs can drive pitch angle scattering of ≲5 keV electrons at rates 10-2-10-4 s-1 and, hence, can contribute to electron losses and conjugated diffuse aurora brightenings. The momentum and pitch angle scattering rates can be comparable, so that EHs can also provide efficient electron heating. The scattering rates driven by EHs at L shells L ˜ 5-8 are comparable to those due to chorus waves and may exceed those due to electron cyclotron harmonics.

Pseudogap in the Eliashberg approach based on electron-phonon and electron-electron-phonon interaction

Energy Technology Data Exchange (ETDEWEB)

Szczesniak, R. [Institute of Physics, Czestochowa University of Technology (Poland); Institute of Physics, Jan Dlugosz University in Czestochowa (Poland); Durajski, A.P.; Duda, A.M. [Institute of Physics, Czestochowa University of Technology (Poland)

2017-04-15

The properties of the superconducting and the anomalous normal state were described by using the Eliashberg method. The pairing mechanism was reproduced with the help of the Hamiltonian, which models the electron-phonon and the electron-electron-phonon interaction (EEPh). The set of the Eliashberg equations, which determines the order parameter function (φ), the wave function renormalization factor (Z), and the energy shift function (χ), was derived. It was proven that for the sufficiently large values of the EEPh potential, the doping dependence of the order parameter (φ/Z) has the analogous course to that observed experimentally in cuprates. The energy gap in the electron density of states is induced by Z and χ - the contribution from φ is negligible. The electron density of states possesses the characteristic asymmetric form and the pseudogap is observed above the critical temperature. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Carbon Nanotube Electron Gun

Science.gov (United States)

Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

2013-01-01

An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

Molecular electron affinities

International Nuclear Information System (INIS)

Fukuda, E.K.

1983-01-01

Molecular electron affinities have historically been difficult quantities to measure accurately. These difficulties arise from differences in structure between the ion and neutral as well as the existence of excited negative ion states. To circumvent these problems, relative electron affinities were determined in this dissertation by studying equilibrium electron transfer reactions using a pulsed ion cyclotron resonance (ICR) spectrometer. Direct measurement of ion and neutral concentrations for reactions of the general type, A - + B = B - + A, allow calculation of the equilibrium constant and, therefore, the free energy change. The free energy difference is related to the difference in electron affinities between A and B. A relative electron affinity scale covering a range of about 45 kcal/mol was constructed with various substituted p-benzoquinones, nitrobenzenes, anhydrides, and benzophenones. To assign absolute electron affinities, various species with accurately known electron affinities are tied to the scale via ion-cyclotron double resonance bracketing techniques. After the relative scale is anchored to these species with well-known electron affinities, the scale is then used as a check on other electron affinity values as well as generating new electron affinity values. Many discrepancies were found between the electron affinities measured using the ICR technique and previous literature determinations

Nonambipolar electron source

International Nuclear Information System (INIS)

Longmier, B.; Baalrud, S.; Hershkowitz, N.

2006-01-01

A radio frequency (rf) plasma-based electron source that does not rely on electron emission at a cathode surface has been constructed. All of the random electron flux incident on an exit aperture is extracted through an electron sheath resulting in total nonambipolar flow within the device when the ratio of the ion loss area to the electron loss area is approximately equal to the square root of the ratio of the ion mass to the electron mass, and the ion sheath potential drop at the chamber walls is much larger than T e /e. The nonambipolar electron source (NES) has an axisymmetric magnetic field of 100 G at the extraction aperture that results in a uniform plasma potential across the aperture, allowing the extraction of all the incident electron flux without the use of grids. A prototype NES has produced 15 A of continuous electron current, using 15 SCCM (SCCM denotes cubic centimeter per minute at STP) Ar, 1200 W rf power at 13.56 MHz, and 6 times gas utilization. Alternatively 8 A of electron current can be produced, using 3 SCCM Ar at 1200 W rf and 20 times gas utilization. NES could replace hollow cathode electron sources in a wide variety of applications

Electron-plasmon model in the electron liquid theory

Directory of Open Access Journals (Sweden)

M.V.Vavrukh

2005-01-01

Full Text Available Here we propose an accurate approach to the description of the electron liquid model in the electron and plasmon terms. Our ideas in the present paper are close to the conception of the collective variables which was developed in the papers of Bohm and Pines. However we use another body of mathematics in the transition to the expanded space of variable particles and plasmons realized by the transition operator. It is evident that in the Random Phase Approximation (RPA, the model which consists of two interactive subsystems of electrons and plasmons is equivalent to the electron liquid model with Coulomb interaction.

Polymer electronics

CERN Document Server

Hsin-Fei, Meng

2013-01-01

Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

A direct electron detector for time-resolved MeV electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Vecchione, T.; Denes, P.; Jobe, R. K.; Johnson, I. J.; Joseph, J. M.; Li, R. K.; Perazzo, A.; Shen, X.; Wang, X. J.; Weathersby, S. P.; Yang, J.; Zhang, D.

2017-03-01

The introduction of direct electron detectors enabled the structural biology revolution of cryogenic electron microscopy. Direct electron detectors are now expected to have a similarly dramatic impact on time-resolved MeV electron microscopy, particularly by enabling both spatial and temporal jitter correction. Here we report on the commissioning of a direct electron detector for time-resolved MeV electron microscopy. The direct electron detector demonstrated MeV single electron sensitivity and is capable of recording megapixel images at 180 Hz. The detector has a 15-bit dynamic range, better than 30-μmμm spatial resolution and less than 20 analogue-to-digital converter count RMS pixel noise. The unique capabilities of the direct electron detector and the data analysis required to take advantage of these capabilities are presented. The technical challenges associated with generating and processing large amounts of data are also discussed.

Coherent Electron Focussing in a Two-Dimensional Electron Gas.

NARCIS (Netherlands)

Houten, H. van; Wees, B.J. van; Mooij, J.E.; Beenakker, C.W.J.; Williamson, J.G.; Foxon, C.T.

1988-01-01

The first experimental realization of ballistic point contacts in a two-dimensional electron gas for the study of transverse electron focussing by a magnetic field is reported. Multiple peaks associated with skipping orbits of electrons reflected specularly by the channel boundary are observed. At

A study on the secondary electrons in a clinical electron beam

International Nuclear Information System (INIS)

Krithivas, G.; Rao, S.N.

1989-01-01

The central axis dose of a 12 MeV clinical electron beam is investigated in terms of an axial component due to primary electrons in the central ray and a lateral component due to secondary electrons originating from multiple scattering of electrons in the off-axis rays. To this effect secondary electron fluence measurements in a polystyrene medium irradiated with a collimated beam are made with a sensitive diode detector. This leads to a construction of secondary electron depth-dose profiles for beam sizes of diameters ranging from 1.7 to 17.4 cm. The results indicate that the lateral electrons account for 25% of the dose in the therapeutic region. For these electrons, the depth of dose maximum is correlated with diffusion depth and maximum lateral excursion in the medium. Dose component due to backscatter electrons at depths is also investigated using a thin-window parallel-plate ion chamber. The role of lateral and backscatter electrons in characterising central axis per cent depth-dose is discussed. (author)

Immunological systematics of the extinct quagga (Equidae).

Science.gov (United States)

Lowenstein, J M; Ryder, O A

1985-09-15

It has been debated whether the extinct quagga was a distinct fourth species of African zebra or whether it was merely the southern variant of the Plains zebra (Equus burchelli). Using a radioimmunoassay (RIA) technique, we have shown that proteins remaining in quagga skins from museums are much more similar to serum proteins of the Plains zebra than to those of the other two extant zebras.

Physiological responses of donkeys (Equus asinus, Perissodactyla ...

African Journals Online (AJOL)

admin

2013-04-03

Apr 3, 2013 ... This is because faecal water loss can account for ... rocky terrain. Donkeys have wooly hair which insulates .... lity, in hot climate, heat loss in donkeys has been obser- ved. ... need supplements, especially throughout the dry season, ..... Ambali SF, Akanbi D, Shittu M, Giwa A, Oladipo OO, Ayo JO (2010a).

Electronics for dummies

CERN Document Server

Shamieh

2015-01-01

Explore the basic concepts of electronics, build your electronics workbench, and begin creating fun electronics projects right away! Electronics For Dummies, 3rd Edition is your guide to the world of electronics. Spanning circuitry, wiring, robotics, transmitters, amplifiers, and more, this book demystifies electricity basics and beyond. The third edition offers new content revised to reflect the latest advancements in the electronics field, and it offers full color project examples to spark your creativity and inspire you to put your new skills to use! Packed with projects that can be comple

Electron holography

CERN Document Server

Tonomura, Akira

1993-01-01

Holography was devised for breaking through the resolution limit of electron microscopes The advent of a "coherent" field emission electron beam has enabled the use of Electron Holography in various areas of magnetic domain structures observation, fluxon observation in superconductors, and fundamental experiments in physics which have been inaccessible using other techniques After examining the fundamentals of electron holography and its applications to the afore mentioned fields, a detailed discussion of the Aharonov-Bohm effect and the related experiments is presented Many photographs and illustrations are included to elucidate the text

Comprehensive analysis of electron correlations in three-electron atoms

International Nuclear Information System (INIS)

Morishita, T.; Lin, C.D.

1999-01-01

We study the electron correlations in singly, doubly, and triply excited states of a three-electron atom. While electron correlation in general is weak for singly excited states, correlation plays major roles in determining the characteristics of doubly and triply excited states. Using the adiabatic approximation in hyperspherical coordinates, we show that the distinction between singly, doubly, and triply excited states is determined by the radial correlations, while finer distinctions within doubly or triply excited states lie in the angular correlations. Partial projections of the body-fixed frame wave functions are used to demonstrate the characteristic nodal surfaces which provide clues to the energy ordering of the states. We show that doubly excited states of a three-electron atom exhibit correlations that are similar to the doubly excited states of a two-electron atom. For the triply excited states, we show that the motion of the three electrons resemble approximately that of a symmetric top. copyright 1999 The American Physical Society

Advanced electron beam techniques

International Nuclear Information System (INIS)

Hirotsu, Yoshihiko; Yoshida, Yoichi

2007-01-01

After 100 years from the time of discovery of electron, we now have many applications of electron beam in science and technology. In this report, we review two important applications of electron beam: electron microscopy and pulsed-electron beam. Advanced electron microscopy techniques to investigate atomic and electronic structures, and pulsed-electron beam for investigating time-resolved structural change are described. (author)

Effects of electron-electron interactions on electronic transport in disordered systems

International Nuclear Information System (INIS)

Foley, Simon Timothy

2002-01-01

This thesis is concerned with the role of electron-electron interactions on electronic transport in disordered systems. We first consider a novel non-linear sigma model in order to microscopically treat the effects of disorder and electronic interaction. We successfully reproduce the perturbative results for the zero-bias anomaly and the interaction correction to the conductivity in a weakly disordered system, and discuss possible directions for future work. Secondly we consider the fluctuations of the dephasing rate for a closed diffusive and quantum dot system. Using the Keldysh technique we derive an expression for the inelastic scattering rate with which we self-consistently obtain the fluctuations in the dephasing rate. For the diffusive regime we find the relative fluctuations is given by F ∼ (L φ /L) 2 /g 2 , where g is the dimensionless conductance, L φ is the dephasing length and L is the sample size. For the quantum dot regime we find a perturbative divergence due to the presence of the zero mode. By mapping divergent diagrams to those for the two-level correlation function, we conjecture the existence of an exact relation between the two. Finally we discuss the consequences of this relation. (author)

Characteristics of trapped electrons and electron traps in single crystals

International Nuclear Information System (INIS)

Budzinski, E.E.; Potter, W.R.; Potienko, G.; Box, H.C.

1979-01-01

Two additional carbohydrates are reported whose crystal structures trap electrons intermolecularly in single crystals x irradiated at low temperature, namely sucrose and rhamnose. Five carbohydrate and polyhydroxy compounds are now known which exhibit this phenomenon. The following characteristics of the phenomenon were investigated: (1) the hyperfine couplings of the electron with protons of the polarized hydroxy groups forming the trap; (2) the distances between these protons and the trapped electron; (3) the spin density of the electron at the protons and (4) the relative stabilities of the electron trapped in various crystal structures

Electron-electron scattering in linear transport in two-dimensional systems

DEFF Research Database (Denmark)

Hu, Ben Yu-Kuang; Flensberg, Karsten

1996-01-01

We describe a method for numerically incorporating electron-electron scattering in quantum wells for small deviations of the distribution function from equilibrium, within the framework of the Boltzmann equation. For a given temperature T and density n, a symmetric matrix needs to be evaluated only...... once, and henceforth it can be used to describe electron-electron scattering in any Boltzmann equation linear-response calculation for that particular T and n. Using this method, we calculate the distribution function and mobility for electrons in a quantum well, including full finite...

Terahertz Plasma Waves in Two Dimensional Quantum Electron Gas with Electron Scattering

International Nuclear Information System (INIS)

Zhang Liping

2015-01-01

We investigate the Terahertz (THz) plasma waves in a two-dimensional (2D) electron gas in a nanometer field effect transistor (FET) with quantum effects, the electron scattering, the thermal motion of electrons and electron exchange-correlation. We find that, while the electron scattering, the wave number along y direction and the electron exchange-correlation suppress the radiation power, but the thermal motion of electrons and the quantum effects can amplify the radiation power. The radiation frequency decreases with electron exchange-correlation contributions, but increases with quantum effects, the wave number along y direction and thermal motion of electrons. It is worth mentioning that the electron scattering has scarce influence on the radiation frequency. These properties could be of great help to the realization of practical THz plasma oscillations in nanometer FET. (paper)

Oblique electron cyclotron emission for electron distribution studies (invited)

International Nuclear Information System (INIS)

Preische, S.; Efthimion, P.C.; Kaye, S.M.

1997-01-01

Electron cyclotron emission (ECE) at an oblique angle to the magnetic field provides a means of probing the electron distribution function both in energy and physical space through changes in and constraints on the relativistic electron cyclotron resonance condition. Diagnostics based on this Doppler shifted resonance are able to study a variety of electron distributions through changes in the location of the resonance in physical or energy space accomplished by changes in the viewing angle and frequency, and the magnetic field. For the case of observation across a changing magnetic field, such as across the tokamak midplane, the constraint on the resonance condition for real solutions to the dispersion relation can constrain the physical location of optically thin emission. A new Oblique ECE diagnostic was installed and operated on the PBX-M tokamak for the study of energetic electrons during lower hybrid current drive. It has a view 33 degree with respect to perpendicular in the tokamak midplane, receives second harmonic X-mode emission, and is constrained to receive single pass emission by SiC viewing dumps on the tokamak walls. Spatial localization of optically thin emission from superthermal electrons (50 endash 100 keV) was obtained by observation of emission upshifted from a thermal cyclotron harmonic. The localized measurements of the electron energy distribution and the superthermal density profile made by this diagnostic demonstrate its potential to study the spatial transport of energetic electrons on fast magnetohydrodynamic time scales or anomalous diffusion time scales. Oblique ECE can also be used to study electron distributions that may have a slight deviation from a Maxwellian by localizing the emission in energy space. (Abstract Truncated)

Electron microscopy of boron carbide before and after electron irradiation

International Nuclear Information System (INIS)

Stoto, T.; Zuppiroli, L.; Beauvy, M.; Athanassiadis, T.

1984-06-01

The microstructure of boron carbide has been studied by electron microscopy and related to the composition of the material. After electron irradiations in an usual transmission electron microscope and in a high voltage electron microscope at different temperatures and fluxes no change of these microstructures have been observed but a sputtering of the surface of the samples, which has been studied quantitatively [fr

Electron Cyclotron Resonances in Electron Cloud Dynamics

International Nuclear Information System (INIS)

Celata, Christine; Celata, C.M.; Furman, Miguel A.; Vay, J.-L.; Yu, Jennifer W.

2008-01-01

We report a previously unknown resonance for electron cloud dynamics. The 2D simulation code 'POSINST' was used to study the electron cloud buildup at different z positions in the International Linear Collider positron damping ring wiggler. An electron equilibrium density enhancement of up to a factor of 3 was found at magnetic field values for which the bunch frequency is an integral multiple of the electron cyclotron frequency. At low magnetic fields the effects of the resonance are prominent, but when B exceeds ∼(2 pi mec/(elb)), with lb = bunch length, effects of the resonance disappear. Thus short bunches and low B fields are required for observing the effect. The reason for the B field dependence, an explanation of the dynamics, and the results of the 2D simulations and of a single-particle tracking code used to elucidate details of the dynamics are discussed

Role of electron-electron interactions in the RKKY theory of magnetism

International Nuclear Information System (INIS)

Cooke, J.F.

1978-10-01

The theory of magnetism in heavy rare earth metals is based on the RKKY theory. In this formalism the indirect exchange interaction between the local 4f spins is mediated by the conduction electrons. When carried to second order in the 4f-conduction electron interaction, traditional perturbation theory leads to a Heisenberg-like interaction between the local spins which depends on the electronic energy bands and 4f-conduction electron exchange matrix elements. This derivation neglects the detailed behavior of electron-electron interaction within the conduction band, which is known to be important in metallic systems. By using an equation of motion method, an expression for the inelastic neutron scattering cross-section has been derived which includes, in an approximate way, this electron-electron interaction. The results of this calculation indicate that spin-wave peaks can be broadened and shifted if the spin-wave band lies near the conduction electron Stoner continuum. The origin of this effect is similar to that found in itinerant electron systems where the spin-wave band actually intersects the Stoner continuum, resulting in the disappearance of the spin-wave mode

Role of electron-electron interactions in the RKKY theory of magnetism

International Nuclear Information System (INIS)

Cooke, J.F.

1979-01-01

The theory of magnetism in heavy rare earth metals is based on the RKKY theory. In this formalism the indirect exchange interaction between the local 4f spins is mediated by the conduction electrons. When carried to second order in the 4f-conduction electron interaction, traditional pertubation theory leads to a Heisenberg-like interaction between the local spins which depends on the electronic energy bands and 4f-conduction electron exchange matrix elements. This derivation neglects the detailed behavior of electron-electron interaction within the conduction band, which is known to be important in metallic systems. By using an equation of motion method, an expression for the inelastic neutron scattering cross-section has been derived which includes, in an approximate way, this electron-electron interaction. The results of this calculation indicate that spin-wave peaks can be broadened and shifted if the spin-wave band lies near the conduction electron Stoner continuum. The origin of this effect is similar to that found in itinerant electron systems where the spin-wave band actually intersects the Stoner continuum, resulting in the disappearance of the spin-wave mode

Electron acoustic solitary waves in unmagnetized two electron population dense plasmas

International Nuclear Information System (INIS)

Mahmood, S.; Masood, W.

2008-01-01

The electron acoustic solitary waves are studied in unmagnetized two population electron quantum plasmas. The quantum hydrodynamic model is employed with the Sagdeev potential approach to describe the arbitrary amplitude electron acoustic waves in a two electron population dense Fermi plasma. It is found that hot electron density hump structures are formed in the subsonic region in such type of quantum plasmas. The wave amplitude as well as the width of the soliton are increased with the increase of percentage presence of cold (thinly populated) electrons in a multicomponent quantum plasma. It is found that an increase in quantum diffraction parameter broadens the nonlinear structure. Furthermore, the amplitude of the nonlinear electron acoustic wave is found to increase with the decrease in Mach number. The numerical results are also presented to understand the formation of solitons in two electron population Fermi plasmas.

Advances in imaging and electron physics the scanning transmission electron microscope

CERN Document Server

Hawkes, Peter W

2009-01-01

Advances in Imaging and Electron Physics merges two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. This series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains.  This particular volume presents several timely articles on the scanning transmission electron microscope. Updated with contributions from leading international scholars and industry experts Discusses hot topic areas and presents current and future research trends Provides an invaluable reference and guide for physicists, engineers and mathematicians.

Attractive electron correlation in wide band gap semiconductors by electron-photon interaction

International Nuclear Information System (INIS)

Takeda, Hiroyuki; Yoshino, Katsumi

2004-01-01

We theoretically demonstrate attractive electron correlation in wide band gap semiconductors by electron-photon interaction. At low temperature, wavevectors of electromagnetic waves absorbed in wide band gap semiconductors cannot be neglected for wavevectors of electron waves; that is, electromagnetic waves affect the movements of electrons. In particular, attractive interaction occurs between two electrons when one electron changes from a valence band to a conduction band and the other electron changes from a conduction band to a valence band

Electronic Publishing or Electronic Information Handling?

Science.gov (United States)

Heck, A.

The current dramatic evolution in information technology is bringing major modifications in the way scientists communicate. The concept of 'electronic publishing' is too restrictive and has often different, sometimes conflicting, interpretations. It is thus giving way to the broader notion of 'electronic information handling' encompassing the diverse types of information, the different media, as well as the various communication methodologies and technologies. New problems and challenges result also from this new information culture, especially on legal, ethical, and educational grounds. The procedures for validating 'published material' and for evaluating scientific activities will have to be adjusted too. 'Fluid' information is becoming a common concept. Electronic publishing cannot be conceived without link to knowledge bases nor without intelligent information retrieval tools.

Theoretical study of the interplay of electron-electron interaction and disorder

International Nuclear Information System (INIS)

Brezini, A.; Behilil, S.

1988-10-01

A disordered Hubbard model with diagonal disorder is used to investigate the electron localization effects associated with both disorder and electron-electron interaction. Extensive results are reported on the ground state properties and compared to other theories. Two regimes have been found: when the electron-electron interaction u is greater than the disorder parameter w and when u < w. (author). 18 refs, 4 figs

Defining Electron Bifurcation in the Electron-Transferring Flavoprotein Family.

Science.gov (United States)

Garcia Costas, Amaya M; Poudel, Saroj; Miller, Anne-Frances; Schut, Gerrit J; Ledbetter, Rhesa N; Fixen, Kathryn R; Seefeldt, Lance C; Adams, Michael W W; Harwood, Caroline S; Boyd, Eric S; Peters, John W

2017-11-01

Electron bifurcation is the coupling of exergonic and endergonic redox reactions to simultaneously generate (or utilize) low- and high-potential electrons. It is the third recognized form of energy conservation in biology and was recently described for select electron-transferring flavoproteins (Etfs). Etfs are flavin-containing heterodimers best known for donating electrons derived from fatty acid and amino acid oxidation to an electron transfer respiratory chain via Etf-quinone oxidoreductase. Canonical examples contain a flavin adenine dinucleotide (FAD) that is involved in electron transfer, as well as a non-redox-active AMP. However, Etfs demonstrated to bifurcate electrons contain a second FAD in place of the AMP. To expand our understanding of the functional variety and metabolic significance of Etfs and to identify amino acid sequence motifs that potentially enable electron bifurcation, we compiled 1,314 Etf protein sequences from genome sequence databases and subjected them to informatic and structural analyses. Etfs were identified in diverse archaea and bacteria, and they clustered into five distinct well-supported groups, based on their amino acid sequences. Gene neighborhood analyses indicated that these Etf group designations largely correspond to putative differences in functionality. Etfs with the demonstrated ability to bifurcate were found to form one group, suggesting that distinct conserved amino acid sequence motifs enable this capability. Indeed, structural modeling and sequence alignments revealed that identifying residues occur in the NADH- and FAD-binding regions of bifurcating Etfs. Collectively, a new classification scheme for Etf proteins that delineates putative bifurcating versus nonbifurcating members is presented and suggests that Etf-mediated bifurcation is associated with surprisingly diverse enzymes. IMPORTANCE Electron bifurcation has recently been recognized as an electron transfer mechanism used by microorganisms to maximize

Effects of electron-electron interactions on the electron distribution function of a plasma in the presence of an external electric field

International Nuclear Information System (INIS)

Molinari, V.G.; Pizzio, F.; Spiga, G.

1979-01-01

The electron distribution function, the electron temperature and some transport parameters (electrical conductivity and energy flow coefficient) are obtained starting from the nonlinear Boltzmann equation for a plasma under the action of an external electric field. The Fokker-Planck approximation is used for electron-electron and electron-ion interactions. The effects of electron-electron collisions are studied for different values of collision frequencies and electric field. (author)

Electron-excited molecule interactions

International Nuclear Information System (INIS)

Christophorou, L.G.; Tennessee Univ., Knoxville, TN

1991-01-01

In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10 6 to 10 7 times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs

Seeing with electrons

International Nuclear Information System (INIS)

Nellist, P.

2006-01-01

Commercially available lens correctors are extending the reach of electron microscopes to unprecedented atomic scales, as Peter Nellist describes. The electron microscope was invented in 1933 and is based on the principle that electrons have a wavelength that is inversely proportional to their momentum. There are two basic types: transmission electron microscopes and scanning electron microscopes, plus a hybrid of the two. The lenses in an electron microscope are provided by electromagnetic fields, but they suffer from spherical aberration. The addition of octupole and quadrupole corrector fields has improved the resolution of the electron microscope to better than 0.1 nm in the last decade. The next step is to correct for chromatic aberration, after which the resolution of the microscope will probably be limited by the size of the atom itself. (U.K.)

Introduction to electronics

CERN Multimedia

CERN. Geneva

2005-01-01

Electronics in HEP experiments: specificities and evolution The Art of Electronics: is there something beyond Ohm's law? Basic building blocks of Analog electronics: quickly understanding a schematic Charge preamps, current preamps and future preamps, shaping and the rest Electronics noise: fundamental and practical Evolution of technology: ASICs, FPGAs...

Multiple electron generation in a sea of electronic states

Science.gov (United States)

Witzel, Wayne; Shabaev, Andrew; Efros, Alexander; Hellberg, Carl; Verne, Jacobs

2009-03-01

In traditional bulk semiconductor photovoltaics (PVs), each photon may excite a single electron-hole, wasting excess energy beyond the band-gap as heat. In nanocrystals, multiple excitons can be generated from a single photon, enhancing the PV current. Multiple electron generation (MEG) may result from Coulombic interactions of the confined electrons. Previous investigations have been based on incomplete or over-simplified electronic-state representations. We present results of quantum simulations that include hundreds of thousands of configuration states and show how the complex dynamics, even in a closed electronic system, yields a saturated MEG effect on a femtosecond timescale. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Electron collision cross sections and electron swarm parameters for gas molecules

International Nuclear Information System (INIS)

Hayashi, Makoto

1986-01-01

Elastic and inelastic electron collision cross sections for molecules which interest in radiation research have been determined from available electron beam and electron swarm data by utilizing the Boltzmann equation and Monte Carlo simulation method. Electron drift velocity data which interest in radiation Pysics have been discussed and some calculated results of electron drift velocity data for CF 4 and CF 4 -inert gases mixtures will be presented. (author)

Electronic payment systems

OpenAIRE

Mláka, Michal

2010-01-01

This bachelor thesis analysis issue of electronic payment systems. It discusses their use for payments on the internet and sending funds via e-mail. The first part is devoted to the theoretical definition and legislation of the issuance of electronic money and activities of electronic money institutions. The main part of the work clearly focuses on the use of e-wallets, which is an integral part of electronic payment systems. E-wallet of electronic payment system Moneybookers is considered as...

Wigner-like crystallization of Anderson-localized electron systems with low electron densities

CERN Document Server

Slutskin, A A; Pepper, M

2002-01-01

We consider an electron system under conditions of strong Anderson localization, taking into account interelectron long-range Coulomb repulsion. We establish that at sufficiently low electron densities and sufficiently low temperatures the Coulomb electron interaction brings about ordering of the Anderson-localized electrons into a structure that is close to an ideal (Wigner) crystal lattice, provided the dimension of the system is > 1. This Anderson-Wigner glass (AWG) is a new macroscopic electron state that, on the one hand, is beyond the conventional Fermi glass concept, and on the other hand, qualitatively differs from the known 'plain' Wigner glass (inherent in self-localized electron systems) in that the random slight electron displacements from the ideal crystal sites essentially depend on the electron density. With increasing electron density the AWG is found to turn into the plain Wigner glass or Fermi glass, depending on the width of the random spread of the electron levels. It is shown that the res...

Excess electrons in methanol clusters: Beyond the one-electron picture

Science.gov (United States)

Pohl, Gábor; Mones, Letif; Turi, László

2016-10-01

We performed a series of comparative quantum chemical calculations on various size negatively charged methanol clusters, ("separators=" CH 3 OH ) n - . The clusters are examined in their optimized geometries (n = 2-4), and in geometries taken from mixed quantum-classical molecular dynamics simulations at finite temperature (n = 2-128). These latter structures model potential electron binding sites in methanol clusters and in bulk methanol. In particular, we compute the vertical detachment energy (VDE) of an excess electron from increasing size methanol cluster anions using quantum chemical computations at various levels of theory including a one-electron pseudopotential model, several density functional theory (DFT) based methods, MP2 and coupled-cluster CCSD(T) calculations. The results suggest that at least four methanol molecules are needed to bind an excess electron on a hydrogen bonded methanol chain in a dipole bound state. Larger methanol clusters are able to form stronger interactions with an excess electron. The two simulated excess electron binding motifs in methanol clusters, interior and surface states, correlate well with distinct, experimentally found VDE tendencies with size. Interior states in a solvent cavity are stabilized significantly stronger than electron states on cluster surfaces. Although we find that all the examined quantum chemistry methods more or less overestimate the strength of the experimental excess electron stabilization, MP2, LC-BLYP, and BHandHLYP methods with diffuse basis sets provide a significantly better estimate of the VDE than traditional DFT methods (BLYP, B3LYP, X3LYP, PBE0). A comparison to the better performing many electron methods indicates that the examined one-electron pseudopotential can be reasonably used in simulations for systems of larger size.

Electron dose rate and photon contamination in electron arc therapy

International Nuclear Information System (INIS)

Pla, M.; Podgorsak, E.B.; Pla, C.

1989-01-01

The electron dose rate at the depth of dose maximum dmax and the photon contamination are discussed as a function of several parameters of the rotational electron beam. A pseudoarc technique with an angular increment of 10 degrees and a constant number of monitor units per each stationary electron field was used in our experiments. The electron dose rate is defined as the electron dose at a given point in phantom divided by the number of monitor units given for any one stationary electron beam. For a given depth of isocenter di the electron dose rates at dmax are linearly dependent on the nominal field width w, while for a given w the dose rates are inversely proportional to di. The dose rates for rotational electron beams with different di are related through the inverse square law provided that the two beams have (di,w) combinations which give the same characteristic angle beta. The photon dose at the isocenter depends on the arc angle alpha, field width w, and isocenter depth di. For constant w and di the photon dose at isocenter is proportional to alpha, for constant alpha and w it is proportional to di, and for constant alpha and di it is inversely proportional to w. The w and di dependence implies that for the same alpha the photon dose at the isocenter is inversely proportional to the electron dose rate at dmax

Power Electronics

DEFF Research Database (Denmark)

Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

2008-01-01

is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...... emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine...... technology from kW to MW, discuss which power electronic solutions are most feasible and used today....

Electron Emission from Ultra-Large Area MOS Electron Emitters

DEFF Research Database (Denmark)

Thomsen, Lasse Bjørchmar; Nielsen, Gunver; Vendelbo, Søren Bastholm

2009-01-01

Ultralarge metal-oxide-semiconductor (MOS) devices with an active oxide area of 1 cm2 have been fabricated for use as electron emitters. The MOS structures consist of a Si substrate, a SiO2 tunnel barrier (~5 nm), a Ti wetting layer (3–10 Å), and a Au top layer (5–60 nm). Electron emission from...... layer is varied from 3 to 10 Å which changes the emission efficiency by more than one order of magnitude. The apparent mean free path of ~5 eV electrons in Au is found to be 52 Å. Deposition of Cs on the Au film increased the electron emission efficiency to 4.3% at 4 V by lowering the work function....... Electron emission under high pressures (up to 2 bars) of Ar was observed. ©2009 American Vacuum Society...

Comparative analysis of the terms "electronic commerce" and "electronic business"

OpenAIRE

Kavaliauskienė, Virginija; Šarapovas, Tadas

2002-01-01

Establishing the terms that clearly and consistently describe growing and dynamic networked economy is a critical first step toward further analysis and evaluation of electronic commerce and electronic business processes. Electronic commerce is making an impact on the ways that purchasing activities are being conducted. Much of the early literature on this subject was very speculative. However, the growth of e-commerce has enabled more observations to be made of the use of electronic business...

Electron-electron interaction and transfer ionization in fast ion-atom collisions

International Nuclear Information System (INIS)

Voitkiv, A B

2008-01-01

Recently it was pointed out that electron capture occurring in fast ion-atom collisions can proceed via a mechanism which earlier was not considered. In the present paper we study this mechanism in more detail. Similarly as in radiative capture, where the electron transfer occurs due to the interaction with the radiation field and proceeds via emission of a photon, within this mechanism the electron capture is caused by the interaction with another atomic electron leading mainly to the emission of the latter. In contrast to the electron-electron Thomas capture, this electron-electron (E-E) mechanism is basically a first-order one having similarities to the kinematic and radiative capture channels. It also possesses important differences with the latter two. Leading to transfer ionization, this first-order capture mechanism results in the electron emission mainly in the direction opposite to the motion of the projectile ion. The same, although less pronounced, feature is also characteristic for the momenta of the target recoil ions produced via this mechanism. It is also shown that the action of the E-E mechanism is clearly seen in recent experimental data on the transfer ionization in fast proton-helium collisions.

Determination of electron temperature and electron density in ...

African Journals Online (AJOL)

It is seen that the electron temperature increases from 5.8 × 102 oK to 7.83 × 104 oK as the pd is reduced from 130mm Hg × mm to 60 mm Hg × mm for argon. The electron densities increases from 2.8 × 1011/cm3 to 3.2 × 1011 /cm3 for the same variation of pds. For air the electron temperature increases from 3.6 × 104 oK to ...

Optimising electron microscopy experiment through electron optics simulation

Energy Technology Data Exchange (ETDEWEB)

Kubo, Y. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Hitachi High-Technologies Corporation, 882, Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Gatel, C.; Snoeck, E. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Houdellier, F., E-mail: florent.houdellier@cemes.fr [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France)

2017-04-15

We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300 kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. - Highlights: • Using dedicated electron optics software, we calculate full electrons trajectories inside a modern transmission electron microscope. • We have determined how to deal with multi-scale electron optics elements like high voltage cold field emission source. • W • e have succeed to model both weak and strong magnetic lenses whether in saturated or unsaturated conditions as well as electrostatic biprism and magnetic deflectors. • We have applied this model

Optimising electron microscopy experiment through electron optics simulation

International Nuclear Information System (INIS)

Kubo, Y.; Gatel, C.; Snoeck, E.; Houdellier, F.

2017-01-01

We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300 kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. - Highlights: • Using dedicated electron optics software, we calculate full electrons trajectories inside a modern transmission electron microscope. • We have determined how to deal with multi-scale electron optics elements like high voltage cold field emission source. • W • e have succeed to model both weak and strong magnetic lenses whether in saturated or unsaturated conditions as well as electrostatic biprism and magnetic deflectors. • We have applied this model

Lead-Free Electronics: Impact for Space Electronics

Science.gov (United States)

Sampson, Michael J.

2010-01-01

Pb is used as a constituent in solder alloys used to connect and attach electronic parts to printed wiring boards (PWBs). Similar Pbbearing alloys are electroplated or hot dipped onto the terminations of electronic parts to protect the terminations and make them solderable. Changing to Pb-free solders and termination finishes has introduced significant technical challenges into the supply chain. Tin/lead (Sn/Pb) alloys have been the solders of choice for electronics for more than 50 years. Pb-free solder alloys are available but there is not a plug-in replacement for 60/40 or 63/37 (Sn/Pb) alloys, which have been the industry workhorses.

Observation of electron plasma waves in plasma of two-temperature electrons

International Nuclear Information System (INIS)

Ikezawa, Shunjiro; Nakamura, Yoshiharu.

1981-01-01

Propagation of electron plasma waves in a large and unmagnetized plasma containing two Maxwellian distributions of electrons is studied experimentally. Two kinds of plasma sources which supply electrons of different temperature are used. The temperature ratio is about 3 and the density ratio of hot to cool electrons is varied from 0 to 0.5. A small contamination of hot electrons enhances the Landau damping of the principal mode known as the Bohm-Gross mode. When the density of hot electrons is larger than about 0.2, two modes are observed. The results agree with theoretical dispersion relations when excitation efficiencies of the modes are considered. (author)

Electron energy and electron trajectories in an inverse free-electron laser accelerator based on a novel electrostatic wiggler

Science.gov (United States)

Nikrah, M.; Jafari, S.

2016-06-01

We expand here a theory of a high-gradient laser-excited electron accelerator based on an inverse free-electron laser (inverse-FEL), but with innovations in the structure and design. The electrostatic wiggler used in our scheme, namely termed the Paul wiggler, is generated by segmented cylindrical electrodes with applied oscillatory voltages {{V}\\text{osc}}(t) over {{90}\\circ} segments. The inverse-FEL interaction can be described by the equations that govern the electron motion in the combined fields of both the laser pulse and Paul wiggler field. A numerical study of electron energy and electron trajectories has been made using the fourth-order Runge-Kutta method. The results indicate that the electron attains a considerable energy at short distances in this device. It is found that if the electron has got sufficient suitable wiggler amplitude intensities, it can not only gain higher energy in longer distances, but also can retain it even after the passing of the laser pulse. In addition, the results reveal that the electron energy gains different peaks for different initial axial velocities, so that a suitable small initial axial velocity of e-beam produces substantially high energy gain. With regard to the transverse confinement of the electron beam in a Paul wiggler, there is no applied axial guide magnetic field in this device.

Plasmaspheric electron content

International Nuclear Information System (INIS)

Hartmann, G.K.

1978-01-01

Measurements of the plasmaspheric electron content are reviewed with particular reference to the ATS-6 radio beacon experiment. From the review, it appears likely that measurement of the plasmaspheric electron content is the only one capable of monitoring electron fluxes continuously between L 1 and L 2. Some recent important results deduced from plasmaspheric electron content measurements are discussed

A 20 keV electron gun system for the electron irradiation experiments

International Nuclear Information System (INIS)

Mahapatra, S.K.; Dhole, S.D.; Bhoraskar, V.N.

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 μA. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure ∼10 -7 mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours

A 20 keV electron gun system for the electron irradiation experiments

Energy Technology Data Exchange (ETDEWEB)

Mahapatra, S.K. [Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, University of Pune, Pune 411007 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India)]. E-mail: vnb@physics.unipune.ernet.in

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 {mu}A. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure {approx}10{sup -7} mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours.

Effect of electron beam on the properties of electron-acoustic rogue waves

Science.gov (United States)

El-Shewy, E. K.; Elwakil, S. A.; El-Hanbaly, A. M.; Kassem, A. I.

2015-04-01

The properties of nonlinear electron-acoustic rogue waves have been investigated in an unmagnetized collisionless four-component plasma system consisting of a cold electron fluid, Maxwellian hot electrons, an electron beam and stationary ions. It is found that the basic set of fluid equations is reduced to a nonlinear Schrodinger equation. The dependence of rogue wave profiles and the associated electric field on the carrier wave number, normalized density of hot electron and electron beam, relative cold electron temperature and relative beam temperature are discussed. The results of the present investigation may be applicable in auroral zone plasma.

Electron cooling and recombination experiments with an adiabatically expanded electron beam

International Nuclear Information System (INIS)

Pastuszka, S.; Heidelberg Univ.; Schramm, U.; Heidelberg Univ.; Grieser, M.; Heidelberg Univ.; Broude, C.; Heidelberg Univ.; Grimm, R.; Heidelberg Univ.; Habs, D.; Heidelberg Univ.; Kenntner, J.; Heidelberg Univ.; Miesner, H.J.; Heidelberg Univ.; Schuessler, T.; Heidelberg Univ.; Schwalm, D.; Heidelberg Univ.; Wolf, A.; Heidelberg Univ.

1996-01-01

Magnetically guided electron beams with transverse temperatures reduced with respect to the cathode temperature by a factor of more than 7 were realized in the electron cooling device of the heavy-ion storage ring TSR and the effect of the reduced transverse temperature in recombination and electron cooling experiments was studied. Measured dielectronic recombination resonances at low relative energy and spectra of laser-stimulated recombination indicate that transverse electron temperatures of about 17 meV have been obtained at cathode temperatures of about 110 meV. The temperature dependence of the spontaneous electron-ion recombination rate during electron cooling was investigated and found to follow the inverse square-root law expected from the theory of radiative recombination, although the measured absolute rates are higher than predicted. A new method based on analyzing the intensity of the fluorescence light emitted during simultaneous laser and electron cooling is used to measure the longitudinal electron cooling force in a range of relative velocities extending over two orders of magnitude (10 5 -10 7 cm/s). The results confirm the occurrence of 'magnetized electron cooling' also at the reduced transverse temperature and show that, compared to earlier measurements at the high transverse temperature, the cooling force increases by about a factor of 2; a considerably larger increase by a factor of ∼5 would be expected if 'magnetized electron cooling' would not exist. (orig.)

Electronic structure of elements and compounds and electronic phases of solids

International Nuclear Information System (INIS)

Nadykto, B.A.

2000-01-01

The paper reviews technique and computed energies for various electronic states of many-electron multiply charged ions, molecular ions, and electronic phases of solids. The model used allows computation of the state energy for free many-electron multiply charged ions with relative accuracy ∼10 -4 suitable for analysis of spectroscopy data

Three-dimensional nanofabrication by electron-beam-induced deposition using 200-keV electrons in scanning transmission electron microscope

International Nuclear Information System (INIS)

Liu, Z.Q.; Mitsuishi, K.; Furuya, K.

2005-01-01

Attempts were made to fabricate three-dimensional nanostructures on and out of a substrate by electron-beam-induced deposition in a 200-kV scanning transmission electron microscope. Structures with parallel wires over the substrate surface were difficult to fabricate due to the direct deposition of wires on both top and bottom surfaces of the substrate. Within the penetration depth of the incident electron beam, nanotweezers were fabricated by moving the electron beam beyond different substrate layers. Combining the deposition of self-supporting wires and self-standing tips, complicated three-dimensional doll-like, flag-like, and gate-like nanostructures that extend out of the substrate were successfully fabricated with one-step or multi-step scans of the electron beam. Effects of coarsening, nucleation, and distortion during electron-beam-induced deposition are discussed. (orig.)

Secondary electron emission yield in the limit of low electron energy

CERN Document Server

Andronov, A.N.; Kaganovich, I.D.; Startsev, E.A.; Raitses, Y.; Demidov, V.I.

2013-04-22

Secondary electron emission (SEE) from solids plays an important role in many areas of science and technology.1 In recent years, there has been renewed interest in the experimental and theoretical studies of SEE. A recent study proposed that the reflectivity of very low energy electrons from solid surface approaches unity in the limit of zero electron energy2,3,4, If this was indeed the case, this effect would have profound implications on the formation of electron clouds in particle accelerators,2-4 plasma measurements with electrostatic Langmuir probes, and operation of Hall plasma thrusters for spacecraft propulsion5,6. It appears that, the proposed high electron reflectivity at low electron energies contradicts to numerous previous experimental studies of the secondary electron emission7. The goal of this note is to discuss possible causes of these contradictions.

Electron spectroscopy

International Nuclear Information System (INIS)

Hegde, M.S.

1979-01-01

An introduction to the various techniques in electron spectroscopy is presented. These techniques include: (1) UV Photoelectron spectroscopy, (2) X-ray Photoelectron spectroscopy, (3) Auger electron spectroscopy, (4) Electron energy loss spectroscopy, (5) Penning ionization spectroscopy and (6) Ion neutralization spectroscopy. The radiations used in each technique, the basis of the technique and the special information obtained in structure determination in atoms and molecules by each technique are summarised. (A.K.)

Perpendicular electron cyclotron emission from hot electrons in TMX-U

International Nuclear Information System (INIS)

James, R.A.; Ellis, R.F.; Lasnier, C.J.; Casper, T.A.; Celata, C.M.

1984-01-01

Perpendicular electron cyclotron emission (PECE) from the electron cyclotron resonant heating of hot electrons in TMX-U is measured at 30 to 40 and 50 to 75 GHz. This emission is optically thin and is measured at the midplane, f/sub ce/ approx. = 14 GHz, in either end cell. In the west end cell, the emission can be measured at different axial positions thus yielding the temporal history of the hot electron axial profile. These profiles are in excellent agreement with the axial diamagnetic signals. In addition, the PECE signal level correlates well with the diamagnetic signal over a wide range of hot electron densities. Preliminary results from theoretical modeling and comparisons with other diagnostics are also presented

A ferroelectric electron gun in a free-electron maser experiment

International Nuclear Information System (INIS)

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

2002-01-01

An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 μs pulse width. The pulse repetition frequency attains 3.1 MHz in ∼50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices

A ferroelectric electron gun in a free-electron maser experiment

CERN Document Server

Einat, M; Rosenman, G

2002-01-01

An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 mu s pulse width. The pulse repetition frequency attains 3.1 MHz in approx 50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices.

Paper electronics.

Science.gov (United States)

Tobjörk, Daniel; Österbacka, Ronald

2011-05-03

Paper is ubiquitous in everyday life and a truly low-cost substrate. The use of paper substrates could be extended even further, if electronic applications would be applied next to or below the printed graphics. However, applying electronics on paper is challenging. The paper surface is not only very rough compared to plastics, but is also porous. While this is detrimental for most electronic devices manufactured directly onto paper substrates, there are also approaches that are compatible with the rough and absorptive paper surface. In this review, recent advances and possibilities of these approaches are evaluated and the limitations of paper electronics are discussed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Destabilization of the electron Bernstein modes by runaway electrons

International Nuclear Information System (INIS)

Hitchcock, D.A.; Mahajan, S.M.

1982-01-01

It is shown that the electromagnetic finite k/sub parallel/ electron Bernstein mode can be destabilized by the runaway electron distribution which results from the quasilinear action of the magnetized plasma oscillation. This mechanism is shown to yield growth rates of the order of 10 8 sec -1 and is suggested as a mechanism for the enchanced cyclotron harmonic emission in the presence of runaway electrons

Surface-electronic-state effects in electron emission from the Be(0001) surface

International Nuclear Information System (INIS)

Archubi, C. D.; Gravielle, M. S.; Silkin, V. M.

2011-01-01

We study the electron emission produced by swift protons impinging grazingly on a Be(0001) surface. The process is described within a collisional formalism using the band-structure-based (BSB) approximation to represent the electron-surface interaction. The BSB model provides an accurate description of the electronic band structure of the solid and the surface-induced potential. Within this approach we derive both bulk and surface electronic states, with these latter characterized by a strong localization at the crystal surface. We found that such surface electronic states play an important role in double-differential energy- and angle-resolved electron emission probabilities, producing noticeable structures in the electron emission spectra.

Surface-electronic-state effects in electron emission from the Be(0001) surface

Energy Technology Data Exchange (ETDEWEB)

Archubi, C. D. [Instituto de Astronomia y Fisica del Espacio, casilla de correo 67, sucursal 28, C1428EGA, Buenos Aires (Argentina); Gravielle, M. S. [Instituto de Astronomia y Fisica del Espacio, casilla de correo 67, sucursal 28, C1428EGA, Buenos Aires (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Silkin, V. M. [Donostia International Physics Center, E-20018 San Sebastian (Spain); Departamento de Fisica de Materiales, Facultad de Ciencias Quimicas, Universidad del Pais Vasco, Apartado 1072, E-20080 San Sebastian (Spain); IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao (Spain)

2011-07-15

We study the electron emission produced by swift protons impinging grazingly on a Be(0001) surface. The process is described within a collisional formalism using the band-structure-based (BSB) approximation to represent the electron-surface interaction. The BSB model provides an accurate description of the electronic band structure of the solid and the surface-induced potential. Within this approach we derive both bulk and surface electronic states, with these latter characterized by a strong localization at the crystal surface. We found that such surface electronic states play an important role in double-differential energy- and angle-resolved electron emission probabilities, producing noticeable structures in the electron emission spectra.

[The morphology and differential diagnosis of parasitic larvae of Triodontophorus (Nematoda, Strongylidae)].

Science.gov (United States)

Kharchenko, V A; Dvoĭnos, G M

1989-01-01

356 parasitic larvae of the genus Triodontophorus from Equidae (two Equus hemionus and one E. grevyi) have been investigated. They belong to three phenons, which differ from each other by the shape and dimensions of a stoma, the structure of teeth and other signs. That phenons belong to three different species: T. serratus, T. tenuicollis and T. brevicauda. The differential diagnosis of L4 of that species of Triodontophorus are given.

Prime Contract Awards Over $25,000 by Major System, Contractor and State, FY83.

Science.gov (United States)

1983-01-01

EQUIPMENT 100 EP3CO INC ILLIN 6130 CONVERTERS ELECTRICAL NON ROTATING 201 EQUUS TOOL CORP OHIO 2540 VEHICULAR FURNITURE AND ACCESSORIES 74 Ea 4710 PIPE...LOUISVILLE UNIVERSITY OF KENTU 1095 MISCELLANEOUS WEAPONS MARCONI INSTRUMENTS NEW J 6115 GENERATORS AND GENERATOR SETS ELECTRICAL OLIN CORP ILLIN 1305...AMOUNT FSF ARMY CARTRI DOE--------------------- 50 CAL 4 BALL I TRACER OLIN CORP FLORI 1376 BULK EXPLOSIVES S 17,633 FUK ARMY CARTRIDE

Simulation of the electron acoustic instability for a finite-size electron beam system

International Nuclear Information System (INIS)

Lin, C.S.; Winske, D.

1987-01-01

Satellite observations at midlatitudes (≅20,000 km) near the earth's dayside polar cusp boundary layer indicate that the upward electron beams have a narrow latitudinal width up to 0.1 0 . In the cusp boundary layer where the electron population consists of a finite-size electron beam in a background of uniform cold and hot electrons, the electron acoustic mode is unstable inside the electron beam but damped outside the electron beam. Simulations of the electron acoustic instability for a finite-size beam system are carried out with a particle-in-cell code to investigate the heating phenomena associated with the instability and the width of the heating region. The simulations show that the finite-size electron beam radiates electrostatic electron acoustic waves. The decay length of the electron acoustic waves outside the beam in the simulation agrees with the spatial decay length derived from the linear dispersion equation

Arbitrary amplitude slow electron-acoustic solitons in three-electron temperature space plasmas

International Nuclear Information System (INIS)

Mbuli, L. N.; Maharaj, S. K.; Bharuthram, R.; Singh, S. V.; Lakhina, G. S.

2015-01-01

We examine the characteristics of large amplitude slow electron-acoustic solitons supported in a four-component unmagnetised plasma composed of cool, warm, hot electrons, and cool ions. The inertia and pressure for all the species in this plasma system are retained by assuming that they are adiabatic fluids. Our findings reveal that both positive and negative potential slow electron-acoustic solitons are supported in the four-component plasma system. The polarity switch of the slow electron-acoustic solitons is determined by the number densities of the cool and warm electrons. Negative potential solitons, which are limited by the cool and warm electron number densities becoming unreal and the occurrence of negative potential double layers, are found for low values of the cool electron density, while the positive potential solitons occurring for large values of the cool electron density are only limited by positive potential double layers. Both the lower and upper Mach numbers for the slow electron-acoustic solitons are computed and discussed

Electron cloud dynamics in the Cornell Electron Storage Ring Test Accelerator wiggler

Directory of Open Access Journals (Sweden)

C. M. Celata

2011-04-01

Full Text Available The interference of stray electrons (also called “electron clouds” with accelerator beams is important in modern intense-beam accelerators, especially those with beams of positive charge. In magnetic wigglers, used, for instance, for transverse emittance damping, the intense synchrotron radiation produced by the beam can generate an electron cloud of relatively high density. In this paper the complicated dynamics of electron clouds in wigglers is examined using the example of a wiggler in the Cornell Electron Storage Ring Test Accelerator experiment at the Cornell Electron Storage Ring. Three-dimensional particle-in-cell simulations with the WARP-POSINST computer code show different density and dynamics for the electron cloud at locations near the maxima of the vertical wiggler field when compared to locations near the minima. Dynamics in these regions, the electron cloud distribution vs longitudinal position, and the beam coherent tune shift caused by the wiggler electron cloud will be discussed.

Arbitrary amplitude fast electron-acoustic solitons in three-electron component space plasmas

Energy Technology Data Exchange (ETDEWEB)

Mbuli, L. N.; Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); Department of Physics, University of the Western Cape (UWC), Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Bharuthram, R. [Department of Physics, University of the Western Cape (UWC), Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Singh, S. V.; Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India); Department of Physics, University of the Western Cape (UWC), Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa)

2016-06-15

We examine the characteristics of fast electron-acoustic solitons in a four-component unmagnetised plasma model consisting of cool, warm, and hot electrons, and cool ions. We retain the inertia and pressure for all the plasma species by assuming adiabatic fluid behaviour for all the species. By using the Sagdeev pseudo-potential technique, the allowable Mach number ranges for fast electron-acoustic solitary waves are explored and discussed. It is found that the cool and warm electron number densities determine the polarity switch of the fast electron-acoustic solitons which are limited by either the occurrence of fast electron-acoustic double layers or warm and hot electron number density becoming unreal. For the first time in the study of solitons, we report on the coexistence of fast electron-acoustic solitons, in addition to the regular fast electron-acoustic solitons and double layers in our multi-species plasma model. Our results are applied to the generation of broadband electrostatic noise in the dayside auroral region.

Electronic Market and Business: Cyberspace vs. Electronic Environment

Directory of Open Access Journals (Sweden)

Deniss Ščeulovs

2013-12-01

Full Text Available The authors of the article analyze the concept "electronic environment". Having studied a range of academic literature sources and other sources, the authors of the article have drawn a conclusion that the academic writings do not provide a definition of "electronic environment". Furthermore, the various opinions among specialists regarding this concept often differ. Meanwhile, there are several explanations of the term "cyberspace" overlapping the concept of "electronic environment", and these terms are often believed to be synonyms. To understand what the term "electronic environment" means and to properly and correctly employ this concept in entrepreneurship, the authors have performed a lexicographic analysis of this concept by comparing reciprocal concepts. As a result of the research, the authors propose their view on what, in their opinion, "electronic environment" is and what its connection to the concept "cyberspace" is. The topicality of the article lies in the fact that often entrepreneurs and specialists of public and other institutions, when using these terms, imply completely different concepts. It can lead to misunderstanding and misinterpreting the information, as well as to encumbering the understanding of tasks, problems, etc.

Practical XHV electron gun

International Nuclear Information System (INIS)

Urata, Tomohiro; Ishikawa, Tsuyoshi; Cho, Boklae; Oshima, Chuhei

2008-01-01

We have developed practical XHV chambers of a electron gun, of which the operating pressures are 1x10 -9 Pa in a stainless-steel one and 4x10 -9 Pa in a permalloy one. By mounting a noble single-atom electron source with high brightness and high spatial coherence on the electron gun including electron optics, we demonstrated highly collimated electron-beam emission: ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources. In XHV, in addition, we confirmed stable electron emission up to 20 nA, which results in the specimen current high enough for scanning electron microscopes. (author)

Two-Electron Transfer Pathways.

Science.gov (United States)

Lin, Jiaxing; Balamurugan, D; Zhang, Peng; Skourtis, Spiros S; Beratan, David N

2015-06-18

The frontiers of electron-transfer chemistry demand that we develop theoretical frameworks to describe the delivery of multiple electrons, atoms, and ions in molecular systems. When electrons move over long distances through high barriers, where the probability for thermal population of oxidized or reduced bridge-localized states is very small, the electrons will tunnel from the donor (D) to acceptor (A), facilitated by bridge-mediated superexchange interactions. If the stable donor and acceptor redox states on D and A differ by two electrons, it is possible that the electrons will propagate coherently from D to A. While structure-function relations for single-electron superexchange in molecules are well established, strategies to manipulate the coherent flow of multiple electrons are largely unknown. In contrast to one-electron superexchange, two-electron superexchange involves both one- and two-electron virtual intermediate states, the number of virtual intermediates increases very rapidly with system size, and multiple classes of pathways interfere with one another. In the study described here, we developed simple superexchange models for two-electron transfer. We explored how the bridge structure and energetics influence multielectron superexchange, and we compared two-electron superexchange interactions to single-electron superexchange. Multielectron superexchange introduces interference between singly and doubly oxidized (or reduced) bridge virtual states, so that even simple linear donor-bridge-acceptor systems have pathway topologies that resemble those seen for one-electron superexchange through bridges with multiple parallel pathways. The simple model systems studied here exhibit a richness that is amenable to experimental exploration by manipulating the multiple pathways, pathway crosstalk, and changes in the number of donor and acceptor species. The features that emerge from these studies may assist in developing new strategies to deliver multiple

Electron-Electron and Electron-Phonon interactions effects on the tunnel electronic spectrum of PbS quantum dots

Science.gov (United States)

Wang, Hongyue; Lhuillier, Emmanuel; Yu, Qian; Mottaghizadeh, Alireza; Ulysse, Christian; Zimmers, Alexandre; Dubertret, Benoit; Aubin, Herve

2015-03-01

We present a tunnel spectroscopy study of the electronic spectrum of single PbS Quantum Dots (QDs) trapped between nanometer-spaced electrodes, measured at low temperature T=5 K. The carrier filling of the QD can be controlled either by the drain voltage in the shell filling regime or by a gate voltage. In the empty QD, the tunnel spectrum presents the expected signature of the 8x degenerated excited levels. In the drain controlled shell filling regime, the levels degeneracies are lifted by the global electrostatic Coulomb energy of the QD; in the gate controlled shell filling regime, the levels degeneracies are lifted by the intra-Coulomb interactions. In the charged quantum dot, electron-phonons interactions lead to the apparition of Franck-Condon side bands on the single excited levels and possibly Franck Condon blockade at low energy. The sharpening of excited levels at higher gate voltage suggests that the magnitude of electron-phonon interactions is decreased upon increasing the electron filling in the quantum dot. This work was supported by the French ANR Grants 10-BLAN-0409-01, 09-BLAN-0388-01, by the Region Ile-de-France in the framework of DIM Nano-K and by China Scholarship Council.

Electron emitting filaments for electron discharge devices

International Nuclear Information System (INIS)

Leung, K.N.; Pincosy, P.A.; Ehlers, K.W.

1988-01-01

This patent describes an electron emitting device for use in an electron discharge system. It comprises: a filament having a pair of terminal ends, electrical supply means for supplying electrical power to the terminal ends of the filament for directly heating the filament by the passage of an electrical current along the filament between the terminal ends, the filament being substantially tapered in cross section continuously in one direction from one of its pair of terminal ends to another of its pair of terminal ends to achieve uniform heating of the filament along the length thereof by compensating for the nonuniform current along the filament due to the emission of electrons therefrom

Electron irradiation-induced destruction of carbon nanotubes in electron microscopes

International Nuclear Information System (INIS)

Molhave, Kristian; Gudnason, Sven Bjarke; Pedersen, Anders Tegtmeier; Clausen, Casper Hyttel; Horsewell, Andy; Boggild, Peter

2007-01-01

Observations of carbon nanotubes under exposure to electron beam irradiation in standard transmission electron microscope (TEM) and scanning electron microscope (SEM) systems show that such treatment in some cases can cause severe damage of the nanotube structure, even at electron energies far below the approximate 100 keV threshold for knock-on damage displacing carbon atoms in the graphene structure. We find that the damage we observe in one TEM can be avoided by use of a cold finger. This and the morphology of the damage imply that water vapour, which is present as a background gas in many vacuum chambers, can damage the nanotube structure through electron beam-induced chemical reactions. Though, the dependence on the background gas makes these observations specific for the presently used systems, the results demonstrate the importance of careful assessment of the level of subtle structural damage that the individual electron microscope system can do to nanostructures during standard use

Electron-attachment processes

International Nuclear Information System (INIS)

Christophorou, L.G.; McCorkle, D.L.; Christodoulides, A.A.

1982-01-01

Topics covered include: (1) modes of production of negative ions, (2) techniques for the study of electron attachment processes, (3) dissociative electron attachment to ground-state molecules, (4) dissociative electron attachment to hot molecules (effects of temperature on dissociative electron attachment), (5) molecular parent negative ions, and (6) negative ions formed by ion-pair processes and by collisions of molecules with ground state and Rydberg atoms

Acceleration of electrons using an inverse free electron laser auto- accelerator

International Nuclear Information System (INIS)

Wernick, I.K.; Marshall, T.C.

1992-07-01

We present data from our study of a device known as the inverse free electron laser. First, numerical simulations were performed to optimize the design parameters for an experiment that accelerates electrons in the presence of an undulator by stimulated absorption of radiation. The Columbia free electron laser (FEL) was configured as an auto-accelerator (IFELA) system; high power (MW's) FEL radiation at ∼1.65 mm is developed along the first section of an undulator inside a quasi-optical resonator. The electron beam then traverses a second section of undulator where a fraction of the electrons is accelerated by stimulated absorption of the 1.65 mm wavelength power developed in the first undulator section. The second undulator section has very low gain and does not generate power on its own. We have found that as much as 60% of the power generated in the first section can be absorbed in the second section, providing that the initial electron energy is chosen correctly with respect to the parameters chosen for the first and second undulators. An electron momentum spectrometer is used to monitor the distribution of electron energies as the electrons exit the IFELA. We have found; using our experimental parameters, that roughly 10% of the electrons are accelerated to energies as high as 1100 keV, in accordance with predictions from the numerical model. The appearance of high energy electrons is correlated with the abrupt absorption of millimeter power. The autoaccelerator configuration is used because there is no intense source of coherent power at the 1.65 mm design wavelength other than the FEL

Advanced Electronics

Science.gov (United States)

2017-07-21

AFRL-RV-PS- AFRL-RV-PS- TR-2017-0114 TR-2017-0114 ADVANCED ELECTRONICS Ashwani Sharma 21 Jul 2017 Interim Report APPROVED FOR PUBLIC RELEASE...NUMBER Advanced Electronics 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62601F 6. AUTHOR(S) 5d. PROJECT NUMBER 4846 Ashwani Sharma 5e. TASK NUMBER...Approved for public release; distribution is unlimited. (RDMX-17-14919 dtd 20 Mar 2018) 13. SUPPLEMENTARY NOTES 14. ABSTRACT The Space Electronics

The Downshift of Electron Plasma Oscillations in the Electron Foreshock Region.

Science.gov (United States)

1984-10-10

Ii D-Ai50 52 THE DOWNSHIFT OF ELECTRON PLASMA OSCILLATIONS IN THE i/1. ELECTRON FORESHOCK R.. (U) I0MM UNIV 10MM CITY DEPT OF PHYSICS AND ASTRONOMY 5...OSCILLATIONS 0 IN THE ELECTRON FORESHOCK REGION In by S. A. Fuselierl, D. A. Gurnett 1 , Ace NTI 0. and R. J. Fitzenreiter 2 DTI I ,3WERSflY o. 06UNDED ISAI...geleasel Ditibto Unlimited 02 1 16 U. of Iowa 84-21 THE DOWNSHIFT OF ELECTRON PLASMA OSCILLATIONSJ / IN THE ELECTRON FORESHOCK REGION t - by Z I S. A

Electronics engineer's reference book

CERN Document Server

Mazda, F F

1989-01-01

Electronics Engineer's Reference Book, Sixth Edition is a five-part book that begins with a synopsis of mathematical and electrical techniques used in the analysis of electronic systems. Part II covers physical phenomena, such as electricity, light, and radiation, often met with in electronic systems. Part III contains chapters on basic electronic components and materials, the building blocks of any electronic design. Part IV highlights electronic circuit design and instrumentation. The last part shows the application areas of electronics such as radar and computers.

Angular distribution of scattered electron and medium energy electron spectroscopy for metals

International Nuclear Information System (INIS)

Oguri, Takeo; Ishioka, Hisamichi; Fukuda, Hisashi; Irako, Mitsuhiro

1986-01-01

The angular distribution (AD) of scattered electrons produced by medium energy incident electrons (E P = 50 ∼ 300 eV) from polycrystalline Ti, Fe, Ni, Cu and Au were obtained by the angle-resolved medium energy electron spectrometer. The AD of the energy loss peaks are similar figures to AD of the elastically reflected electron peaks. Therefore, the exchanged electrons produced by the knock-on collision between the incident electrons and those of metals without momentum transfer are observed as the energy loss spectra (ELS). This interpretation differs from the inconsequent interpretation by the dielectric theory or the interband transition. The information depth and penetration length are obtained from AD of the Auger electron peaks. The contribution of the surface to spectra is 3 % at the maximum for E P = 50 eV. The true secondary peaks representing the secondary electron emission spectroscopy (SES) are caused by the emissions of the energetic electrons (kT e ≥ 4 eV), and SES is the inversion of ELS. The established fundamental view is that the medium energy electron spectra represent the total bulk density of states. (author)

Wigner-like crystallization of Anderson-localized electron systems with low electron densities

International Nuclear Information System (INIS)

Slutskin, A.A.; Kovtun, H.A.; Pepper, M.

2002-01-01

We consider an electron system under conditions of strong Anderson localization, taking into account interelectron long-range Coulomb repulsion. We establish that at sufficiently low electron densities and sufficiently low temperatures the Coulomb electron interaction brings about ordering of the Anderson-localized electrons into a structure that is close to an ideal (Wigner) crystal lattice, provided the dimension of the system is > 1. This Anderson-Wigner glass (AWG) is a new macroscopic electron state that, on the one hand, is beyond the conventional Fermi glass concept, and on the other hand, qualitatively differs from the known 'plain' Wigner glass (inherent in self-localized electron systems) in that the random slight electron displacements from the ideal crystal sites essentially depend on the electron density. With increasing electron density the AWG is found to turn into the plain Wigner glass or Fermi glass, depending on the width of the random spread of the electron levels. It is shown that the residual disorder of the AWG is characterized by a multi-valley ground-state degeneracy akin to that in a spin glass. Some general features of the AWG are discussed, and a new conduction mechanism of a creep type is predicted

3D Printed structural electronics: embedding and connecting electronic components into freeform electronic devices

NARCIS (Netherlands)

Maalderink, H.H.H.; Bruning, F.B.J.; Schipper, M.M.R. de; Werff, J.J.J. van der; Germs, W.W.C.; Remmers, J.J.C.; Meinders, E.R.

2018-01-01

The need for personalised and smart products drives the development of structural electronics with mass-customisation capability. A number of challenges need to be overcome in order to address the potential of complete free form manufacturing of electronic devices. One key challenge is the

3D Printed structural electronics : embedding and connecting electronic components into freeform electronic devices

NARCIS (Netherlands)

Maalderink, H.H.; Bruning, F.B.J.; de Schipper, M.R.; van der Werff, J.J.; Germs, W.C.; Remmers, J.J.C.; Meinders, E.R.

2018-01-01

The need for personalised and smart products drives the development of structural electronics with mass-customisation capability. A number of challenges need to be overcome in order to address the potential of complete free form manufacturing of electronic devices. One key challenge is the

27 CFR 73.32 - May I electronically sign forms I submit electronically to TTB?

Science.gov (United States)

2010-04-01

... AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY (CONTINUED) PROCEDURES AND PRACTICES ELECTRONIC SIGNATURES; ELECTRONIC SUBMISSION OF FORMS Electronic Filing of Documents with TTB § 73.32 May I electronically sign forms I submit electronically to TTB? You may electronically sign the electronic form you...

Electron Bifurcation: Thermodynamics and Kinetics of Two-Electron Brokering in Biological Redox Chemistry.

Science.gov (United States)

Zhang, Peng; Yuly, Jonathon L; Lubner, Carolyn E; Mulder, David W; King, Paul W; Peters, John W; Beratan, David N

2017-09-19

How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation. Remarkably, bifurcating electron transfer (ET) proteins typically send one electron uphill and one electron downhill by similar energies, such that the overall reaction is spontaneous, but not profligate. Electron bifurcation in the NADH-dependent reduced ferredoxin: NADP + oxidoreductase I (Nfn) is explored in detail here. Recent experimental progress in understanding the structure and function of Nfn allows us to dissect its workings in the framework of modern ET theory. The first electron that leaves the two-electron donor flavin (L-FAD) executes a positive free energy "uphill" reaction, and the departure of this electron switches on a second thermodynamically spontaneous ET reaction from the flavin along a second pathway that moves electrons in the opposite direction and at a very different potential. The singly reduced ET products formed from the bifurcating flavin are more than two nanometers distant from each other. In Nfn, the second electron to leave the flavin is much more reducing than the first: the potentials are said to be "crossed." The eventually reduced cofactors, NADH and ferredoxin in the case of Nfn, perform crucial downstream redox

Electronic Elections

DEFF Research Database (Denmark)

Schürmann, Carsten

2009-01-01

Electronic voting technology is a two edged sword. It comes with many risks but brings also many benefits. Instead of flat out rejecting the technology as uncontrollably dangerous, we advocate in this paper a different technological angle that renders electronic elections trustworthy beyond...... the usual levels of doubt. We exploit the trust that voters currently have into the democratic process and model our techniques around that observation accordingly. In particular, we propose a technique of trace emitting computations to record the individual steps of an electronic voting machine...... for a posteriori validation on an acceptably small trusted computing base. Our technology enables us to prove that an electronic elections preserves the voter’s intent, assuming that the voting machine and the trace verifier are independent....

Low-dose electron energy-loss spectroscopy using electron counting direct detectors.

Science.gov (United States)

Maigné, Alan; Wolf, Matthias

2018-03-01

Since the development of parallel electron energy loss spectroscopy (EELS), charge-coupled devices (CCDs) have been the default detectors for EELS. With the recent development of electron-counting direct-detection cameras, micrographs can be acquired under very low electron doses at significantly improved signal-to-noise ratio. In spectroscopy, in particular in combination with a monochromator, the signal can be extremely weak and the detection limit is principally defined by noise introduced by the detector. Here we report the use of an electron-counting direct-detection camera for EEL spectroscopy. We studied the oxygen K edge of amorphous ice and obtained a signal noise ratio up to 10 times higher than with a conventional CCD.We report the application of electron counting to record time-resolved EEL spectra of a biological protein embedded in amorphous ice, revealing chemical changes observed in situ while exposed by the electron beam. A change in the fine structure of nitrogen K and the carbon K edges were recorded during irradiation. A concentration of 3 at% nitrogen was detected with a total electron dose of only 1.7 e-/Å2, extending the boundaries of EELS signal detection at low electron doses.

How do electron localization functions describe π-electron delocalization?

Science.gov (United States)

Steinmann, Stephan N; Mo, Yirong; Corminboeuf, Clemence

2011-12-14

Scalar fields provide an intuitive picture of chemical bonding. In particular, the electron localization function (ELF) has proven to be highly valuable in interpreting a broad range of bonding patterns. The discrimination between enhanced or reduced electron (de)localization within cyclic π-conjugated systems remains, however, challenging for ELF. In order to clearly distinguish between the local properties of ten highly and weakly π-(de)localized prototype systems, we compare the ELFs of both the canonical wave functions and electron-localized states (diabatic) with those of two closely related scalar fields: the electron localizability indicator (ELI-D) and the localized orbital locator (LOL). The simplest LOL function distinguishes enhanced from weak π-(de)localization in an insightful and reliable manner. LOL offers the finest contrast between annulenes with 4n/4n + 2 π electrons and their inorganic analogues as well as between hyperconjugated cyclopentadiene derivatives. LOL(π) also gives an appealing and intuitive picture of the π-bond. In contrast, the most popular ELF fails to capture subtle contrasting local electronic properties and suffers from the arbitrariness of the σ/π dissection. The orbital separation of the most recent ELI-D is clear-cut but the interpretations sometime less straightforward in the present context.

Electron shuttles in biotechnology.

Science.gov (United States)

Watanabe, Kazuya; Manefield, Mike; Lee, Matthew; Kouzuma, Atsushi

2009-12-01

Electron-shuttling compounds (electron shuttles [ESs], or redox mediators) are essential components in intracellular electron transfer, while microbes also utilize self-produced and naturally present ESs for extracellular electron transfer. These compounds assist in microbial energy metabolism by facilitating electron transfer between microbes, from electron-donating substances to microbes, and/or from microbes to electron-accepting substances. Artificially supplemented ESs can create new routes of electron flow in the microbial energy metabolism, thereby opening up new possibilities for the application of microbes to biotechnology processes. Typical examples of such processes include halogenated-organics bioremediation, azo-dye decolorization, and microbial fuel cells. Herein we suggest that ESs can be applied widely to create new microbial biotechnology processes.

Treatment of foods with 'soft-electrons' (low-energy electrons)

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Toru [Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki (Japan); Todoriki, Setsuko [National Food Research Institute (NFRI), Tsukuba, Ibaraki (Japan)

2003-02-01

Electrons with energies of 300 keV or lower were defined as soft-electrons'. Soft-electrons can eradicate microorganisms residing on the surface of grains, pulses, spices, dehydrated vegetables, tea leaves and seeds, and reduce their microbial loads to levels lower than 10 CFU/g with little quality deterioration. Soft-electrons can inactivate insect pests infesting grains and pulses and inhibit sprouting of potatoes. (author)

Electron beam collimation with a photon MLC for standard electron treatments

Science.gov (United States)

Mueller, S.; Fix, M. K.; Henzen, D.; Frei, D.; Frauchiger, D.; Loessl, K.; Stampanoni, M. F. M.; Manser, P.

2018-01-01

Standard electron treatments are currently still performed using standard or molded patient-specific cut-outs placed in the electron applicator. Replacing cut-outs and electron applicators with a photon multileaf collimator (pMLC) for electron beam collimation would make standard electron treatments more efficient and would facilitate advanced treatment techniques like modulated electron radiotherapy (MERT) and mixed beam radiotherapy (MBRT). In this work, a multiple source Monte Carlo beam model for pMLC shaped electron beams commissioned at a source-to-surface distance (SSD) of 70 cm is extended for SSDs of up to 100 cm and validated for several Varian treatment units with field sizes typically used for standard electron treatments. Measurements and dose calculations agree generally within 3% of the maximal dose or 2 mm distance to agreement. To evaluate the dosimetric consequences of using pMLC collimated electron beams for standard electron treatments, pMLC-based and cut-out-based treatment plans are created for a left and a right breast boost, a sternum, a testis and a parotid gland case. The treatment plans consist of a single electron field, either alone (1E) or in combination with two 3D conformal tangential photon fields (1E2X). For each case, a pMLC plan with similar treatment plan quality in terms of dose homogeneity to the target and absolute mean dose values to the organs at risk (OARs) compared to a cut-out plan is found. The absolute mean dose to an OAR is slightly increased for pMLC-based compared to cut-out-based 1E plans if the OAR is located laterally close to the target with respect to beam direction, or if a 6 MeV electron beam is used at an extended SSD. In conclusion, treatment plans using cut-out collimation can be replaced by plans of similar treatment plan quality using pMLC collimation with accurately calculated dose distributions.

Technical report of electronics shop characteristics of high speed electronics component, (1)

International Nuclear Information System (INIS)

Watanabe, Shin-ichi; Shiino, Kazuo.

1975-01-01

We must develop electronics circuits for high speed signals. The electronics components of the circuits make use of the special components. This report treats a pulse response of the electronics components (i.e. coaxial cable, connector, resistor, capacitor, diode, transistor) for high speed electronics. The results of this report was already applied constructions of high speed electronics circuits and experimental equipments of the High Energy Physics Division. (auth.)

Fully printable, strain-engineered electronic wrap for customizable soft electronics.

Science.gov (United States)

Byun, Junghwan; Lee, Byeongmoon; Oh, Eunho; Kim, Hyunjong; Kim, Sangwoo; Lee, Seunghwan; Hong, Yongtaek

2017-03-24

Rapid growth of stretchable electronics stimulates broad uses in multidisciplinary fields as well as industrial applications. However, existing technologies are unsuitable for implementing versatile applications involving adaptable system design and functions in a cost/time-effective way because of vacuum-conditioned, lithographically-predefined processes. Here, we present a methodology for a fully printable, strain-engineered electronic wrap as a universal strategy which makes it more feasible to implement various stretchable electronic systems with customizable layouts and functions. The key aspects involve inkjet-printed rigid island (PRI)-based stretchable platform technology and corresponding printing-based automated electronic functionalization methodology, the combination of which provides fully printed, customized layouts of stretchable electronic systems with simplified process. Specifically, well-controlled contact line pinning effect of printed polymer solution enables the formation of PRIs with tunable thickness; and surface strain analysis on those PRIs leads to the optimized stability and device-to-island fill factor of strain-engineered electronic wraps. Moreover, core techniques of image-based automated pinpointing, surface-mountable device based electronic functionalizing, and one-step interconnection networking of PRIs enable customized circuit design and adaptable functionalities. To exhibit the universality of our approach, multiple types of practical applications ranging from self-computable digital logics to display and sensor system are demonstrated on skin in a customized form.

Fully printable, strain-engineered electronic wrap for customizable soft electronics

Science.gov (United States)

Byun, Junghwan; Lee, Byeongmoon; Oh, Eunho; Kim, Hyunjong; Kim, Sangwoo; Lee, Seunghwan; Hong, Yongtaek

2017-03-01

Rapid growth of stretchable electronics stimulates broad uses in multidisciplinary fields as well as industrial applications. However, existing technologies are unsuitable for implementing versatile applications involving adaptable system design and functions in a cost/time-effective way because of vacuum-conditioned, lithographically-predefined processes. Here, we present a methodology for a fully printable, strain-engineered electronic wrap as a universal strategy which makes it more feasible to implement various stretchable electronic systems with customizable layouts and functions. The key aspects involve inkjet-printed rigid island (PRI)-based stretchable platform technology and corresponding printing-based automated electronic functionalization methodology, the combination of which provides fully printed, customized layouts of stretchable electronic systems with simplified process. Specifically, well-controlled contact line pinning effect of printed polymer solution enables the formation of PRIs with tunable thickness; and surface strain analysis on those PRIs leads to the optimized stability and device-to-island fill factor of strain-engineered electronic wraps. Moreover, core techniques of image-based automated pinpointing, surface-mountable device based electronic functionalizing, and one-step interconnection networking of PRIs enable customized circuit design and adaptable functionalities. To exhibit the universality of our approach, multiple types of practical applications ranging from self-computable digital logics to display and sensor system are demonstrated on skin in a customized form.

Electrons in Nanostructures

DEFF Research Database (Denmark)

Flindt, Christian

2007-01-01

in the possibilities o®ered by the quantum mechanical behavior of electrons when it comes to informa- tion processing. This branch of research is also concerned with fundamental questions in physics. Besides an introduction to the above-mentioned subjects, the thesis con- tains a number of contributions to the ¯elds...... of coherent electron manip- ulation and the statistical description of electron transport through nano- devices. The physics of the electrons are described with a combination of numerical methods, developed and applied in the thesis, and more analytical approaches, which are also discussed. The thesis......-based communication. The statistical description of electron transport through nanostructures is based on rate equations, and the primary contribution of the thesis in that respect is the development of a method that allows for the calculation of the distribution of electrons passing through a device. The method...

Identification of electrons in the ZEUS hadron-electron separator with neural networks

International Nuclear Information System (INIS)

Carstens, J.O.

1994-10-01

An electron finder for the ZEUS experiment was constructed, which is specialized to electrons in the momentum range 0.5 to 3.0 GeV/c. For the first time this electron finder connects the informations of the calorimeter with those of the hadron-electron separator (HES). For this purpose the electron finder was equipped with a neural network. The electron finder reached on a data set of photoproduction events with conversion electrons an efficiency and discriminance of E=(62.9±2.2±0.6)% and D=(91.4±0.8±1.1)%. From these two quantities it can be calculated that the electron finder the ratio electrons to background increases by the factoe E/(1-D)=7.4 (Signal amplification). For the comparison: A neural net, to which only calorimeter informations have been made available, reached at the same efficiency a signal amplification of 2.4. A simple cut in the variable HES-signal reaches a signal amplification of 6.3. Hints were given, how training data sets with electrons and hadrons of higher energies can be obtained. With such data sets the working range of the electron finder can be without problems extended to higher momenta. As preparation for the construction of the electron finder an introduction to the foundations of the mathematics and the application of neural networks was given. By means of examples different methods for the convergence improvement have been tested. Numerous representations mediate illustrative imaginations on the mathematical process of the training of neural networks

Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

Energy Technology Data Exchange (ETDEWEB)

Weathersby, S. P.; Brown, G.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K., E-mail: lrk@slac.stanford.edu; Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); and others

2015-07-15

Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

Secondary electron emission anisotropy in oblique incidence of electrons on the (100) Mo

International Nuclear Information System (INIS)

Gomoyunova, M.V.; Zaslavskij, S.L.; Pronin, I.I.

1978-01-01

Studied was the influence of azimuthal plane of incidence of primary particles with energies of 0.5-1.5 keV on the secondary electron emission of the (100) Mo face at the constant polar angle of 45 deg. The measurements were carried out in vacuum of (2-4)x10 -10 torr by modulation technique. It is shown that anisotropy is peculiar to the secondary electron emission of all energies. The anisotropy of emission has two maxima; the high-energy maximum connected with reflected primary electrons and situated near the elastically reflected electrons and weaker pronounced the low-energy one which is found at energies of 100-200 eV and is conditioned by truly secondary electrons. It is shown that the anisotropy, characterizing secondary electrons responsible for the appearance of structure in spectrum, particularly the Auger electrons and the electrons suffering ionizing energy losses, exceeds the anisotropy of continuous spectrum electrons possessing the same energy. The electron diffraction dynamic theory, based on the conception of the united wave field of electrons, has been used to explain the regularities stated

Kinetic and electron-electron energies for convex sums of ground state densities with degeneracies and fractional electron number

Energy Technology Data Exchange (ETDEWEB)

Levy, Mel, E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, North Carolina A and T State University, Greensboro, North Carolina 27411 (United States); Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States); Anderson, James S. M.; Zadeh, Farnaz Heidar; Ayers, Paul W., E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario (Canada)

2014-05-14

Properties of exact density functionals provide useful constraints for the development of new approximate functionals. This paper focuses on convex sums of ground-level densities. It is observed that the electronic kinetic energy of a convex sum of degenerate ground-level densities is equal to the convex sum of the kinetic energies of the individual degenerate densities. (The same type of relationship holds also for the electron-electron repulsion energy.) This extends a known property of the Levy-Valone Ensemble Constrained-Search and the Lieb Legendre-Transform refomulations of the Hohenberg-Kohn functional to the individual components of the functional. Moreover, we observe that the kinetic and electron-repulsion results also apply to densities with fractional electron number (even if there are no degeneracies), and we close with an analogous point-wise property involving the external potential. Examples where different degenerate states have different kinetic energy and electron-nuclear attraction energy are given; consequently, individual components of the ground state electronic energy can change abruptly when the molecular geometry changes. These discontinuities are predicted to be ubiquitous at conical intersections, complicating the development of universally applicable density-functional approximations.

Embracing Electronic Publishing.

Science.gov (United States)

Wills, Gordon

1996-01-01

Electronic publishing is the grandest revolution in the capture and dissemination of academic and professional knowledge since Caxton developed the printing press. This article examines electronic publishing, describes different electronic publishing scenarios (authors' cooperative, consolidator/retailer/agent oligopsony, publisher oligopoly), and…

Peptide π-Electron Conjugates: Organic Electronics for Biology?

Science.gov (United States)

Ardoña, Herdeline Ann M; Tovar, John D

2015-12-16

Highly ordered arrays of π-conjugated molecules are often viewed as a prerequisite for effective charge-transporting materials. Studies involving these materials have traditionally focused on organic electronic devices, with more recent emphasis on biological systems. In order to facilitate the transition to biological environments, biomolecules that can promote hierarchical ordering and water solubility are often covalently appended to the π-electron unit. This review highlights recent work on π-conjugated systems bound to peptide moieties that exhibit self-assembly and aims to provide an overview on the development and emerging applications of peptide-based supramolecular π-electron systems.

Modified Sternglass theory for the emission of secondary electrons by fast-electron impact

International Nuclear Information System (INIS)

Suszcynsky, D.M.; Borovsky, J.E.

1992-01-01

The Sternglass theory [Sternglass, Phys. Rev. 108, 1 (1957)] for fast-ion-induced secondary-electron emission from metals has been modified to predict the secondary-electron yield from metals impacted by energetic (several keV to about 200 keV) electrons. The primary modification of the theory accounts for the contribution of the backscattered electrons to the production of secondary electrons based on a knowledge of the backscattered-electron energy distribution. The modified theory is in reasonable agreement with recent experimental data from gold targets in the 6--30-keV electron energy range

Calculation of the electron trajectory for 200 kV self-shielded electron accelerator

International Nuclear Information System (INIS)

Wang Shuiqing

2000-01-01

In order to calculate the electron trajectory of 200 kV self-shielded electron accelerator, the electric field is calculated with a TRAJ program. In this program, following electron track mash points one by one, the electron beam trajectories are calculated. Knowing the effect of grid voltage on electron optics and gaining grid voltage focusing effect in the various energy grades, the authors have gained scientific basis for adjusting grid voltage, and also accumulated a wealth of experience for designing self-shielded electron accelerator or electron curtain in future

Electronic inventions and discoveries electronics from its earliest beginnings to the present day

CERN Document Server

Dummer, G W A

1983-01-01

Electronic Inventions and Discoveries: Electronics from Its Earliest Beginnings to the Present Day provides a summary of the development of the whole field of electronics. Organized into 13 chapters, the book covers and reviews the history of electronics as a whole and its aspects. The opening chapter covers the beginnings of electronics, while the next chapter discusses the development of components, transistors, and integrated circuits. The third chapter tackles the expansion of electronics and its effects on industry. The succeeding chapters discuss the history of the aspects of electronics

Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy

Science.gov (United States)

Priebe, Katharina E.; Rathje, Christopher; Yalunin, Sergey V.; Hohage, Thorsten; Feist, Armin; Schäfer, Sascha; Ropers, Claus

2017-12-01

Ultrafast electron and X-ray imaging and spectroscopy are the basis for an ongoing revolution in the understanding of dynamical atomic-scale processes in matter. The underlying technology relies heavily on laser science for the generation and characterization of ever shorter pulses. Recent findings suggest that ultrafast electron microscopy with attosecond-structured wavefunctions may be feasible. However, such future technologies call for means to both prepare and fully analyse the corresponding free-electron quantum states. Here, we introduce a framework for the preparation, coherent manipulation and characterization of free-electron quantum states, experimentally demonstrating attosecond electron pulse trains. Phase-locked optical fields coherently control the electron wavefunction along the beam direction. We establish a new variant of quantum state tomography—`SQUIRRELS'—for free-electron ensembles. The ability to tailor and quantitatively map electron quantum states will promote the nanoscale study of electron-matter entanglement and new forms of ultrafast electron microscopy down to the attosecond regime.

Digital electronics

CERN Document Server

Morris, John

2013-01-01

An essential companion to John C Morris's 'Analogue Electronics', this clear and accessible text is designed for electronics students, teachers and enthusiasts who already have a basic understanding of electronics, and who wish to develop their knowledge of digital techniques and applications. Employing a discovery-based approach, the author covers fundamental theory before going on to develop an appreciation of logic networks, integrated circuit applications and analogue-digital conversion. A section on digital fault finding and useful ic data sheets completes th

The magnetized electron-acoustic instability driven by a warm, field-aligned electron beam

International Nuclear Information System (INIS)

Sooklal, A.; Mace, R.L.

2004-01-01

The electron-acoustic instability in a magnetized plasma having three electron components, one of which is a field-aligned beam of intermediate temperature, is investigated. When the plasma frequency of the cool electrons exceeds the electron gyrofrequency, the electron-acoustic instability 'bifurcates' at sufficiently large propagation angles with respect to the magnetic field to yield an obliquely propagating, low-frequency electron-acoustic instability and a higher frequency cyclotron-sound instability. Each of these instabilities retains certain wave features of its progenitor, the quasiparallel electron-acoustic instability, but displays also new magnetic qualities through its dependence on the electron gyrofrequency. The obliquely propagating electron-acoustic instability requires a lower threshold beam speed for its excitation than does the cyclotron-sound instability, and for low to intermediate beam speeds has the higher maximum growth rate. When the plasma is sufficiently strongly magnetized that the plasma frequency of the cool electrons is less than the electron gyrofrequency, the only instability in the electron-acoustic frequency range is the strongly magnetized electron-acoustic instability. Its growth rate and real frequency exhibit a monotonic decrease with wave propagation angle and it grows at small to intermediate wave numbers where its parallel phase speed is approximately constant. The relevance of the results to the interpretation of cusp auroral hiss and auroral broadband electrostatic noise is briefly discussed

Starting electronics all you need to get a grounding in practical electronics

CERN Document Server

Brindley, Keith

2013-01-01

Starting Electronics is a nine-chapter introductory text to electronics based on feature articles previously published as magazine articles. The opening chapter provides an overview of the fundamentals of electronics. The succeeding chapters present details of some easy-to-do experiments and the current and voltage measurement. The remaining chapters cover some basic components of electronics, including capacitor, integrated circuit, oscillator, filter, diodes, and transistors. This book will prove useful to electronic constructors and students.

Single Electron Tunneling

International Nuclear Information System (INIS)

Ruggiero, Steven T.

2005-01-01

Financial support for this project has led to advances in the science of single-electron phenomena. Our group reported the first observation of the so-called ''Coulomb Staircase'', which was produced by tunneling into ultra-small metal particles. This work showed well-defined tunneling voltage steps of width e/C and height e/RC, demonstrating tunneling quantized on the single-electron level. This work was published in a now well-cited Physical Review Letter. Single-electron physics is now a major sub-field of condensed-matter physics, and fundamental work in the area continues to be conducted by tunneling in ultra-small metal particles. In addition, there are now single-electron transistors that add a controlling gate to modulate the charge on ultra-small photolithographically defined capacitive elements. Single-electron transistors are now at the heart of at least one experimental quantum-computer element, and single-electron transistor pumps may soon be used to define fundamental quantities such as the farad (capacitance) and the ampere (current). Novel computer technology based on single-electron quantum dots is also being developed. In related work, our group played the leading role in the explanation of experimental results observed during the initial phases of tunneling experiments with the high-temperature superconductors. When so-called ''multiple-gap'' tunneling was reported, the phenomenon was correctly identified by our group as single-electron tunneling in small grains in the material. The main focus throughout this project has been to explore single electron phenomena both in traditional tunneling formats of the type metal/insulator/particles/insulator/metal and using scanning tunneling microscopy to probe few-particle systems. This has been done under varying conditions of temperature, applied magnetic field, and with different materials systems. These have included metals, semi-metals, and superconductors. Amongst a number of results, we have

Electron transfer from nucleobase electron adducts to 5-bromouracil. Is guanine an ultimate sink for the electron in irradiated DNA?

International Nuclear Information System (INIS)

Nese, C.; Yuan, Z.; Schuchmann, M.N.; Sonntag, C. von

1992-01-01

Electron transfer to 5-bromouracil (5-BrU) from nucleobase (N) electron adducts (and their protonated forms) has been studied by product analysis and pulse radiolysis. When an electron is transferred to 5-BrU, the ensuing 5-BrU radical anion rapidly loses a bromide ion; the uracilyl radical thus formed reacts with added t-butanol, yielding uracil. From the uracil yields measured as the function of [N]/[5-BrU] after γ-radiolysis of Ar-saturated solutions it is concluded that thymine and adenine electron adducts and their heteroatom-protonated forms transfer electrons quantitatively to 5-BrU. The data raise the question whether in DNA the guanine moiety may act as the ultimate sink of the electron in competition with other processes such as protonation at C(6) of the thymine electron adduct. (Author)

Extreme environment electronics

CERN Document Server

Cressler, John D

2012-01-01

Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

Electron-vibrational transitions under molecular ions collisions with slow electrons

International Nuclear Information System (INIS)

Andreev, E.A.

1993-01-01

A concept of a multichannel quantum defect is considered and basic theoretic ratios of inelastic collisional processes with the participation of molecular positive ions and slow electrons playing an important role both in atmospheric and laboratory plasma, are presented. The problem of scattering channel number limitation with the provision of S-matrix unique character is considered. Different models of electron rotation-vibrational connection under collision of two-atom molecular ions with slow electrons are analysed. Taking N 2 + as an example, a high efficiency of transitions between different electron states of a molecular ion is shown. 73 refs., 9 figs., 1 tab

Electron: Cluster interactions

International Nuclear Information System (INIS)

Scheidemann, A.A.; Knight, W.D.

1994-02-01

Beam depletion spectroscopy has been used to measure absolute total inelastic electron-sodium cluster collision cross sections in the energy range from E ∼ 0.1 to E ∼ 6 eV. The investigation focused on the closed shell clusters Na 8 , Na 20 , Na 40 . The measured cross sections show an increase for the lowest collision energies where electron attachment is the primary scattering channel. The electron attachment cross section can be understood in terms of Langevin scattering, connecting this measurement with the polarizability of the cluster. For energies above the dissociation energy the measured electron-cluster cross section is energy independent, thus defining an electron-cluster interaction range. This interaction range increases with the cluster size

Role of electron-electron scattering on spin transport in single layer graphene

Directory of Open Access Journals (Sweden)

Bahniman Ghosh

2014-01-01

Full Text Available In this work, the effect of electron-electron scattering on spin transport in single layer graphene is studied using semi-classical Monte Carlo simulation. The D’yakonov-P’erel mechanism is considered for spin relaxation. It is found that electron-electron scattering causes spin relaxation length to decrease by 35% at 300 K. The reason for this decrease in spin relaxation length is that the ensemble spin is modified upon an e-e collision and also e-e scattering rate is greater than phonon scattering rate at room temperature, which causes change in spin relaxation profile due to electron-electron scattering.

ELECTRONIC SIGNATURES

African Journals Online (AJOL)

10332324

"[to] promote the understanding and, acceptance of and growth in the number of electronic transactions .... Chapter III of the ECT Act is based on the UNCITRAL Model Law on Electronic. Commerce ... Communications Technology Law 146. 22.

Starting electronics

CERN Document Server

Brindley, Keith

2005-01-01

Starting Electronics is unrivalled as a highly practical introduction for hobbyists, students and technicians. Keith Brindley introduces readers to the functions of the main component types, their uses, and the basic principles of building and designing electronic circuits. Breadboard layouts make this very much a ready-to-run book for the experimenter; and the use of multimeter, but not oscilloscopes, puts this practical exploration of electronics within reach of every home enthusiast's pocket. The third edition has kept the simplicity and clarity of the original. New material

Stretchable electronics

CERN Document Server

Someya, Takao

2012-01-01

With its comprehensive coverage this handbook and ready reference brings together some of the most outstanding scientists in the field to lay down the undisputed knowledge on how to make electronics stretchable.As such, it focuses on gathering and evaluating the materials, designs, models and technologies that enable the fabrication of fully elastic electronic devices which can sustain high strain. Furthermore, it provides a review of those specific applications that directly benefit from highly compliant electronics, including transistors, photonic devices and sensors. In addition to stre

Coherent electron cooling

Energy Technology Data Exchange (ETDEWEB)

Litvinenko,V.

2009-05-04

Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

Electronics pocket book

CERN Document Server

Parr, E A

1981-01-01

Electronics Pocket Book, Fourth Edition is a nonmathematical presentation of the many varied topics covered by electronics. The book tackles electron physics, electronic components (i.e. resistors, capacitors, and conductors), integrated circuits, and the principles of a.c. and d.c. amplifiers. The text also discusses oscillators, digital circuits, digital computers, and optoelectronics (i.e., sensors, emitters, and devices that utilize light). Communications (such as line and radio communications, transmitters, receivers, and digital techniques); the principles and examples of servosystems; a

Sticker electronics

KAUST Repository

Hussain, Muhammad Mustafa; Torres Sevilla, Galo Andres; Diaz Cordero, Marlon Steven

2017-01-01

Electronic stickers may be manufactured on flexible substrates (110, 120, 130) as layers and packaged together. The package may then have an adhesive applied to one side to provide capability for sticking the electronic devices to surfaces

Electronics for LHC Experiments

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-07-01

This document gathers the abstracts of most presentations made at this workshop on electronics for the large hadron collider (LHC) experiments. The presentations were arranged into 6 sessions: 1) electronics for tracker, 2) trigger electronics, 3) detector control systems, 4) data acquisition, 5) electronics for calorimeters and electronics for muons, and 6) links, power systems, grounding and shielding, testing and quality assurance.

Electronics for LHC Experiments

International Nuclear Information System (INIS)

2004-01-01

This document gathers the abstracts of most presentations made at this workshop on electronics for the large hadron collider (LHC) experiments. The presentations were arranged into 6 sessions: 1) electronics for tracker, 2) trigger electronics, 3) detector control systems, 4) data acquisition, 5) electronics for calorimeters and electronics for muons, and 6) links, power systems, grounding and shielding, testing and quality assurance

Electron Bernstein wave electron temperature profile diagnostic (invited)

International Nuclear Information System (INIS)

Taylor, G.; Efthimion, P.; Jones, B.; Munsat, T.; Spaleta, J.; Hosea, J.; Kaita, R.; Majeski, R.; Menard, J.

2001-01-01

Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either ''overdense,'' operating at high density relative to the magnetic field (e.g., ω pe >>Omega ce in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition (τ>2). Electron Bernstein waves (EBWs) are electrostatic waves that can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers as a result of their large k perp . In this article we report on measurements of EBW emission on the CDX-U spherical torus, where B 0 ∼2kG, e >∼10 13 cm -3 and T e ∼10--200eV. Results are presented for electromagnetic measurements of EBW emission, mode converted near the plasma edge. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multipoint Thomson scattering diagnostic. Depending on the plasma conditions, the mode-converted EBW radiation temperature was found to be ≤T e and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe and a 140 GHz interferometer were employed to measure changes in the edge density profile in the vicinity of the upper hybrid resonance where the mode conversion of the EBWs is expected to occur. Initial results suggest EBW emission and EBW heating are viable concepts for plasmas where ω pe >>Omega ce

Electron energy distribution from intense electron beams in the upper mesosphere and lower thermosphere

International Nuclear Information System (INIS)

Martinez-Sanchez, M.; Cheng, Wai; Dvore, D.; Zahniser, M.S.

1992-01-01

A model was developed to calculate the electron energy spectrum created by an electron beam in the upper atmosphere. A significant feature of the model is the inclusion of the effects of electron-electron collisions which are important at high beam intensity when the ratio of the electron to ambient gas density is high. Comparing the calculated results for a 2.6-kV, 20-A beam at 110-km altitude from models with and without the electron-electron collision term, the electron-electron collisions have the effect of smoothing out the electron spectrum in the low-energy region ( 2 and O 2 are filled in, resulting in an increase in the calculated production rate of these species compared with model calculations that neglect this effect

Interaction of electrons with light metal hydrides in the transmission electron microscope.

Science.gov (United States)

Wang, Yongming; Wakasugi, Takenobu; Isobe, Shigehito; Hashimoto, Naoyuki; Ohnuki, Somei

2014-12-01

Transmission electron microscope (TEM) observation of light metal hydrides is complicated by the instability of these materials under electron irradiation. In this study, the electron kinetic energy dependences of the interactions of incident electrons with lithium, sodium and magnesium hydrides, as well as the constituting element effect on the interactions, were theoretically discussed, and electron irradiation damage to these hydrides was examined using in situ TEM. The results indicate that high incident electron kinetic energy helps alleviate the irradiation damage resulting from inelastic or elastic scattering of the incident electrons in the TEM. Therefore, observations and characterizations of these materials would benefit from increased, instead decreased, TEM operating voltage. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Sustainable Management of Electronics

Science.gov (United States)

To provide information on EPAs strategy for electronics stewardship, certified electronics recyclers and the Challenge; as well as where to donate unwanted electronics, how to calculate benefits, and what's going on with electronics mgmt in their states.

Electron acoustic solitary waves in a magnetized plasma with nonthermal electrons and an electron beam

Energy Technology Data Exchange (ETDEWEB)

Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India); University of the Western Cape, Belville (South Africa); Devanandhan, S., E-mail: devanandhan@gmail.com [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Belville (South Africa)

2016-08-15

A theoretical investigation is carried out to study the obliquely propagating electron acoustic solitary waves having nonthermal hot electrons, cold and beam electrons, and ions in a magnetized plasma. We have employed reductive perturbation theory to derive the Korteweg-de-Vries-Zakharov-Kuznetsov (KdV-ZK) equation describing the nonlinear evolution of these waves. The two-dimensional plane wave solution of KdV-ZK equation is analyzed to study the effects of nonthermal and beam electrons on the characteristics of the solitons. Theoretical results predict negative potential solitary structures. We emphasize that the inclusion of finite temperature effects reduces the soliton amplitudes and the width of the solitons increases by an increase in the obliquity of the wave propagation. The numerical analysis is presented for the parameters corresponding to the observations of “burst a” event by Viking satellite on the auroral field lines.

Impulse approximation treatment of electron-electron excitation and ionization in energetic ion-atom collisions

International Nuclear Information System (INIS)

Zouros, T.J.M.; Lee, D.H.; Sanders, J.M.; Richard, P.

1993-01-01

The effect of electron-electron interactions between projectile and target electrons observed in recent measurements of projectile K-shell excitation and ionization using 0 projectile Auger electron spectroscopy are analysed within the framework of the impulse approximation (IA). The IA formulation is seen to give a good account of the threshold behavior of both ionization and excitation, while providing a remarkably simple intuitive picture of such electron-electron interactions in ion-atom collisions in general. Thus, the applicability of the IA treatment is extended to cover most known processes involving such interactions including resonance transfer excitation, binary encounter electron production, electron-electron excitation and ionization. (orig.)

Printed Electronics

Science.gov (United States)

Wade, Jessica; Hollis, Joseph Razzell; Wood, Sebastian

2018-04-01

The combination of printing technology with manufacturing electronic devices enables a new paradigm of printable electronics, where 'smart' functionality can be readily incorporated into almost any product at low cost. Over recent decades, rapid progress has been made in this field, which is now emerging into the industrial andcommercial realm. However, successful development and commercialisation on a large scale presents some significant technical challenges. For fully-printable electronic systems, all the component parts must be deposited from solutions (inks), requiring the development of new inorganic, organic and hybrid materials.A variety of traditional printing techniques are being explored and adapted forprinting these new materials in ways that result in the best performing electronicdevices. Whilst printed electronics research has initially focused on traditional typesof electronic device such as light-emitting diodes, transistors, and photovoltaics, it is increasingly apparent that a much wider range of applications can be realised. The soft and stretchable nature of printable materials makes them perfect candidates forbioelectronics, resulting in a wealth of research looking at biocompatible printable inks and biosensors. Regardless of application, the properties of printed electronicmaterials depend on the chemical structures, processing conditions, device architecture,and operational conditions, the complex inter-relationships of which aredriving ongoing research. We focus on three particular 'hot topics', where attention is currently focused: novel materials, characterisation techniques, and device stability. With progress advancing very rapidly, printed electronics is expected to grow over the next decade into a key technology with an enormous economic and social impact.

Engineered phages for electronics.

Science.gov (United States)

Cui, Yue

2016-11-15

Phages are traditionally widely studied in biology and chemistry. In recent years, engineered phages have attracted significant attentions for functionalization or construction of electronic devices, due to their specific binding, catalytic, nucleating or electronic properties. To apply the engineered phages in electronics, these are a number of interesting questions: how to engineer phages for electronics? How are the engineered phages characterized? How to assemble materials with engineered phages? How are the engineered phages micro or nanopatterned? What are the strategies to construct electronics devices with engineered phages? This review will highlight the early attempts to address these questions and explore the fundamental and practical aspects of engineered phages in electronics, including the approaches for selection or expression of specific peptides on phage coat proteins, characterization of engineered phages in electronics, assembly of electronic materials, patterning of engineered phages, and construction of electronic devices. It provides the methodologies and opens up ex-cit-ing op-por-tu-ni-ties for the development of a variety of new electronic materials and devices based on engineered phages for future applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Electron-electron interactions in graphene field-induced quantum dots in a high magnetic field

DEFF Research Database (Denmark)

Orlof, A.; Shylau, Artsem; Zozoulenko, I. V.

2015-01-01

We study the effect of electron-electron interaction in graphene quantum dots defined by an external electrostatic potential and a high magnetic field. To account for the electron-electron interaction, we use the Thomas-Fermi approximation and find that electron screening causes the formation...... of compressible strips in the potential profile and the electron density. We numerically solve the Dirac equations describing the electron dynamics in quantum dots, and we demonstrate that compressible strips lead to the appearance of plateaus in the electron energies as a function of the magnetic field. Finally...

Tunable Electron-Electron Interactions in LaAlO_{3}/SrTiO_{3} Nanostructures

Directory of Open Access Journals (Sweden)

Guanglei Cheng

2016-12-01

Full Text Available The interface between the two complex oxides LaAlO_{3} and SrTiO_{3} has remarkable properties that can be locally reconfigured between conducting and insulating states using a conductive atomic force microscope. Prior investigations of “sketched” quantum dot devices revealed a phase in which electrons form pairs, implying a strongly attractive electron-electron interaction. Here, we show that these devices with strong electron-electron interactions can exhibit a gate-tunable transition from a pair-tunneling regime to a single-electron (Andreev bound state tunneling regime where the interactions become repulsive. The electron-electron interaction sign change is associated with a Lifshitz transition where the d_{xz} and d_{yz} bands start to become occupied. This electronically tunable electron-electron interaction, combined with the nanoscale reconfigurability of this system, provides an interesting starting point towards solid-state quantum simulation.

Polymer electronics

CERN Document Server

Geoghegan, Mark

2013-01-01

Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

Electron optics

CERN Document Server

Grivet, Pierre; Bertein, F; Castaing, R; Gauzit, M; Septier, Albert L

1972-01-01

Electron Optics, Second English Edition, Part I: Optics is a 10-chapter book that begins by elucidating the fundamental features and basic techniques of electron optics, as well as the distribution of potential and field in electrostatic lenses. This book then explains the field distribution in magnetic lenses; the optical properties of electrostatic and magnetic lenses; and the similarities and differences between glass optics and electron optics. Subsequent chapters focus on lens defects; some electrostatic lenses and triode guns; and magnetic lens models. The strong focusing lenses and pris

Development of a secondary electron energy analyzer for a transmission electron microscope.

Science.gov (United States)

Magara, Hideyuki; Tomita, Takeshi; Kondo, Yukihito; Sato, Takafumi; Akase, Zentaro; Shindo, Daisuke

2018-04-01

A secondary electron (SE) energy analyzer was developed for a transmission electron microscope. The analyzer comprises a microchannel plate (MCP) for detecting electrons, a coil for collecting SEs emitted from the specimen, a tube for reducing the number of backscattered electrons incident on the MCP, and a retarding mesh for selecting the energy of SEs incident on the MCP. The detection of the SEs associated with charging phenomena around a charged specimen was attempted by performing electron holography and SE spectroscopy using the energy analyzer. The results suggest that it is possible to obtain the energy spectra of SEs using the analyzer and the charging states of a specimen by electron holography simultaneously.

Electron beam welding

International Nuclear Information System (INIS)

Schwartz, M.M.

1974-01-01

Electron-beam equipment is considered along with fixed and mobile electron-beam guns, questions of weld environment, medium and nonvacuum welding, weld-joint designs, tooling, the economics of electron-beam job shops, aspects of safety, quality assurance, and repair. The application of the process in the case of individual materials is discussed, giving attention to aluminum, beryllium, copper, niobium, magnesium, molybdenum, tantalum, titanium, metal alloys, superalloys, and various types of steel. Mechanical-property test results are examined along with the areas of application of electron-beam welding

Electronic signal conditioning

CERN Document Server

NEWBY, BRUCE

1994-01-01

At technician level, brief references to signal conditioning crop up in a fragmented way in various textbooks, but there has been no single textbook, until now!More advanced texts do exist but they are more mathematical and presuppose a higher level of understanding of electronics and statistics. Electronic Signal Conditioning is designed for HNC/D students and City & Guilds Electronics Servicing 2240 Parts 2 & 3. It will also be useful for BTEC National, Advanced GNVQ, A-level electronics and introductory courses at degree level.

Vibrational and electronic excitation of hexatriacontane thin films by low energy electron impact

International Nuclear Information System (INIS)

Vilar, M.R.; Schott, M.; Pfluger, P.

1990-01-01

Thin polycrystalline films of hexatriacontane (HTC) were irradiated with low energy (E=0.5--15 eV) electrons, and off-specular backscattered electron spectra were measured. Below E∼7 eV, single and multiple vibrational excitations only are observed, which relax the electrons down to the bottom of the HTC conduction band. Due to the negative electron affinity of HTC, thermal electrons are emitted into vacuum. Structure in the backscattered electron current at kinetic energies about 1.5 and 4 eV are associated to conduction band density of states. Above E∼7 eV, the dominant losses correspond to electronic excitations, excitons, or above a threshold (energy of the electron inside the HTC film) at 9.2±0.1 eV, electron--hole pair generation. The latter process is very efficient and reaches a yield of the order of one ∼11 eV. Evidence for chemical reaction above E∼4 eV is observed

Characterisation of 100 kW electron beam melting gun and its adaptation as electron gun for high power DC electron accelerators

International Nuclear Information System (INIS)

Banerjee, Srutarshi; Bhattacharjee, Dhruva; Waghmare, Abhay; Tiwari, Rajnish; Bakhtsingh, R.I.; Dasgupta, K.; Gupta, Sachin; Prakash, Baibhaw; Jha, M.N.

2015-01-01

The paper deals with the characterization of the 100 kW electron beam melting gun for its adaptation in high power DC Electron Accelerators. The indigenously designed electron beam melting system at BARC is chosen for characterization. It comprises of electron gun as source of electrons, two electromagnetic focusing lenses viz. upper focusing lens and lower focusing lens for beam focusing, intermediate beam aperture for vacuum decoupling between gun region and melt zone, deflection and oscillation lens for maneuvering the beam on the melt charge and water cooled crucible that acts as a beam dump. In this system, the electron gun is designed for 40 kV and 100 kW corresponding to a maximum beam current of 2.5 A. The electron gun uses directly heated spiral tungsten filament. The operating temperature of the filament is 2800 °K. The focusing electrode and the anode profile are designed based on Pierce geometry. High Power DC Electron Accelerators require high currents of 1 A. The beam must comply with the requirement of 40 mm beam diameter and 10 mrad divergence at the exit of the electron gun. The characterization of the existing electron gun was done to find out all the beam parameters, for e.g. beam size, beam divergence, perveance etc. to be adapted or to be modified for the design of electron gun for high power DC accelerators. This paper shows limitations and the possible solutions for design of high power DC accelerators. (author)

Organic High Electron Mobility Transistors Realized by 2D Electron Gas.

Science.gov (United States)

Zhang, Panlong; Wang, Haibo; Yan, Donghang

2017-09-01

A key breakthrough in inorganic modern electronics is the energy-band engineering that plays important role to improve device performance or develop novel functional devices. A typical application is high electron mobility transistors (HEMTs), which utilizes 2D electron gas (2DEG) as transport channel and exhibits very high electron mobility over traditional field-effect transistors (FETs). Recently, organic electronics have made very rapid progress and the band transport model is demonstrated to be more suitable for explaining carrier behavior in high-mobility crystalline organic materials. Therefore, there emerges a chance for applying energy-band engineering in organic semiconductors to tailor their optoelectronic properties. Here, the idea of energy-band engineering is introduced and a novel device configuration is constructed, i.e., using quantum well structures as active layers in organic FETs, to realize organic 2DEG. Under the control of gate voltage, electron carriers are accumulated and confined at quantized energy levels, and show efficient 2D transport. The electron mobility is up to 10 cm 2 V -1 s -1 , and the operation mechanisms of organic HEMTs are also argued. Our results demonstrate the validity of tailoring optoelectronic properties of organic semiconductors by energy-band engineering, offering a promising way for the step forward of organic electronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Downshift of electron plasma oscillations in the electron foreshock region