The Functional Organization and Cortical Connections of Motor Cortex in Squirrels

Science.gov (United States)

Cooke, Dylan F.; Padberg, Jeffrey; Zahner, Tony

2012-01-01

Despite extraordinary diversity in the rodent order, studies of motor cortex have been limited to only 2 species, rats and mice. Here, we examine the topographic organization of motor cortex in the Eastern gray squirrel (Sciurus carolinensis) and cortical connections of motor cortex in the California ground squirrel (Spermophilus beecheyi). We distinguish a primary motor area, M1, based on intracortical microstimulation (ICMS), myeloarchitecture, and patterns of connectivity. A sensorimotor area between M1 and the primary somatosensory area, S1, was also distinguished based on connections, functional organization, and myeloarchitecture. We term this field 3a based on similarities with area 3a in nonrodent mammals. Movements are evoked with ICMS in both M1 and 3a in a roughly somatotopic pattern. Connections of 3a and M1 are distinct and suggest the presence of a third far rostral field, termed “F,” possibly involved in motor processing based on its connections. We hypothesize that 3a is homologous to the dysgranular zone (DZ) in S1 of rats and mice. Our results demonstrate that squirrels have both similar and unique features of M1 organization compared with those described in rats and mice, and that changes in 3a/DZ borders appear to have occurred in both lineages. PMID:22021916

Clinal variation of some mammals during the Holocene in Missouri

Science.gov (United States)

Purdue, James R.

1980-03-01

Eastern cottontail ( Sylvilagus floridanus), fox squirrel ( Sciurus niger), and gray squirrel ( Sciurus carolinensis) were examined for clinal variation during the Holocene. Modern samples of all three species displayed strong east-west patterns along the western edge of the eastern deciduous forest: S. floridanus and S. niger decrease and S. carolinensis increases in size. Archeological samples of S. carolinensis from Rodgers Shelter (23BE125), Benton County, Missouri, and Graham Cave (23MT2), Montgomery County, Missouri, indicated an increase in size from early to middle Holocene. Sylvilagus floridanus from Rodgers Shelter decreased in size from early to middle Holocene and then increased during the late Holocene to modern proportions. A literature survey reveals that clinal variation is a common phenomenon among modern homeotherms. In introduced species, clinal variation has developed after relatively few generations, indicating rapid adaptations to environmental conditions; often winter climatic variables are implicated. Morphological variation in the study species during the Holocene is interpreted as a response to changing climates. Studies of morphological clines may lead to another valuable data source for reconstructing past ecologies.

Beach almond (Terminalia catappa, Combretaceae seed production and predation by scarlet macaws (Ara macao and variegated squirrels (Sciurus variegatoides

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Jonathan J. Henn

2014-09-01

Full Text Available Knowledge of ecological impacts of exotic beach almond (Terminalia catappa in the central Pacific of Costa Rica are little known, but studies have found this species to be a potentially important food source for endangered scarlet macaws (Ara macao. In this study, reproductive phenology and seed predation by variegated squirrels (Sciurus variegatoides and scarlet macaws were measured during March and April 2011 on beaches of central Pacific coastal Costa Rica. Seed productivity and predation levels were quantified on a weekly basis for 111 beach almond trees to assess the importance of beach almond as a food source for scarlet macaws and the extent of resource partitioning between seed predators. Seed production of the trees was great (about 194 272 seeds and approximately 67% of seeds were predated by seed predators. Macaws consumed an estimated 49% of seeds while squirrels consumed 18%. Additionally, evidence of resource partitioning between squirrels and macaws was found. Scarlet macaws preferred to feed on the northern side and edge of the canopy while squirrels preferred to feed on the southern and inside parts of the canopy. Both species ate most seeds on the ocean side of the tree. Despite the status of this tree as an exotic species, the beach almond appears to be an important resource for scarlet macaw population recovery. The resource produced by this tree should be taken into account as reforestation efforts continue in Costa Rica. Rev. Biol. Trop. 62 (3: 929-938. Epub 2014 September 01.

Behaviour and diary activity of Sciurus ingrami (Thomas) in captivity (Rodentia, Sciuridae)

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Bordignon, Marcelo; Monteiro Filho, Emygdio L.A

1997-01-01

From October 1994 to November 1995 the behaviour, postures and diurnal activity of tive captive squirrels Sciurus ingrami were observed and registered. Four basics postures, five grooming behaviours, displacements and face wiping behaviour were identified. Based on behavioural observations, the diurnal activity was divided into four categories: resting, displacement, teeding and maintenance. The time spent in each category varied seasonally and the squirrels spent more time resting during win...

Yield from an intensively hunted population of eastern fox squirrels

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James S. Jordan; James S. Jordan

1971-01-01

Rates at which Eastern fox squirrels (Sciurus niger) are exploited in areas open to public hunting may be useful guides for designing fall hunting seasons that are biologically defensible. However, there is a question whether the harvest of fox squirrels by public hunting will even occasionally be great enough to challenge the limit allowed by the best designed...

Correlates of vulnerability in Chiricahua fox squirrels

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Bret S. Pasch; John L. Koprowski

2005-01-01

Chiricahua fox squirrels (Sciurus nayaritensis chiricahuae) are endemic to the Chiricahua Mountains of southeastern Arizona. A paucity of natural history information and uncertain conservation status served as impetus for us to initiate a descriptive ecological study of the species. We examined reproductive and population ecology of Chiricahua fox...

Asymmetry in food handling behavior of a tree-dwelling rodent (Sciurus vulgaris.

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Nuria Polo-Cavia

Full Text Available Asymmetry in motor patterns is present in a wide variety of animals. Many lateralized behaviors seem to depend on brain asymmetry, as it is the case of different tasks associated to food handling by several bird and mammal species. Here, we analyzed asymmetry in handling behavior of pine cones by red squirrels (Sciurus vulgaris. Red squirrels devote most of their daily activity to feeding, thus this species constitutes an appropriate model for studying asymmetry in food processing. We aimed to explore 1 the potential lateralization in handling of pine cones by squirrels, 2 the dominant pattern for this behavior (left- vs. right-handed, and 3 whether this pattern varies among populations and depending on the pine tree species available. Results revealed that red squirrels handle pine cones in an asymmetrical way, and that direction of asymmetry varies among populations and seems to be determined more by local influences rather than by the pine tree species.

Segregating the Effects of Seed Traits and Common Ancestry of Hardwood Trees on Eastern Gray Squirrel Foraging Decisions.

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Sundaram, Mekala; Willoughby, Janna R; Lichti, Nathanael I; Steele, Michael A; Swihart, Robert K

2015-01-01

The evolution of specific seed traits in scatter-hoarded tree species often has been attributed to granivore foraging behavior. However, the degree to which foraging investments and seed traits correlate with phylogenetic relationships among trees remains unexplored. We presented seeds of 23 different hardwood tree species (families Betulaceae, Fagaceae, Juglandaceae) to eastern gray squirrels (Sciurus carolinensis), and measured the time and distance travelled by squirrels that consumed or cached each seed. We estimated 11 physical and chemical seed traits for each species, and the phylogenetic relationships between the 23 hardwood trees. Variance partitioning revealed that considerable variation in foraging investment was attributable to seed traits alone (27-73%), and combined effects of seed traits and phylogeny of hardwood trees (5-55%). A phylogenetic PCA (pPCA) on seed traits and tree phylogeny resulted in 2 "global" axes of traits that were phylogenetically autocorrelated at the family and genus level and a third "local" axis in which traits were not phylogenetically autocorrelated. Collectively, these axes explained 30-76% of the variation in squirrel foraging investments. The first global pPCA axis, which produced large scores for seed species with thin shells, low lipid and high carbohydrate content, was negatively related to time to consume and cache seeds and travel distance to cache. The second global pPCA axis, which produced large scores for seeds with high protein, low tannin and low dormancy levels, was an important predictor of consumption time only. The local pPCA axis primarily reflected kernel mass. Although it explained only 12% of the variation in trait space and was not autocorrelated among phylogenetic clades, the local axis was related to all four squirrel foraging investments. Squirrel foraging behaviors are influenced by a combination of phylogenetically conserved and more evolutionarily labile seed traits that is consistent with a weak

Excretory urography by subcutaneous injection of iodixanol in Persian squirrel (Sciurus anomalous)

International Nuclear Information System (INIS)

Veshkini, A.; Tavana, M.; Haghdost, I.S.; Masouleh, M.N.; Savojbolaghi, S.H.

2011-01-01

There are many indications for excretory urography in humans and animals. Intravenous urography (IVU) is the most practical method about other urography techniques are used because of difficulties for finding veins in IVU, due to small size of the patients. This study was performed to evaluate the feasibility of subcutaneous injection of iodixanol in providing a safe and diagnostic urogram in Persian squirrel. Twelve clinically healthy adult Persian squirrels were prepared and kept for two weeks prior to study. Blood tests were performed 7 days prior to the study. After eighteen hour fasting, animals were sedated by using xylazine/diazepam cocktail (xylazine 5mg/kg, diazepam 30mg/kg). Lateral and ventrodorsal control radiographs were taken. Thirteen hundred and 1800 mg iodine per kilogram body weight of iodixanol was injected subcutaneously over shoulder area in Persian squirrels (each dose for six Persian squirrels). Lateral and ventrodorsal radiographs were taken every 5 m

Functional differentiation of trailing and leading forelimbs during locomotion on the ground and on a horizontal branch in the European red squirrel (Sciurus vulgaris, Rodentia).

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Schmidt, André

2011-06-01

Mammalian locomotion is characterized by the frequent use of in-phase gaits in which the footfalls of the left and right fore- or hindlimbs are unevenly spaced in time. Although previous studies have identified a functional differentiation between the first limb (trailing limb) and the second limb (leading limb) to touch the ground during terrestrial locomotion, the influence of a horizontal branch on limb function has never been explored. To determine the functional differences between trailing and leading forelimbs during locomotion on the ground and on a horizontal branch, X-ray motion analysis and force measurements were carried out in two European red squirrels (Sciurus vulgaris, Rodentia). The differences observed between trailing and leading forelimbs were minimal during terrestrial locomotion, where both limbs fulfill two functions and go through a shock-absorbing phase followed by a generating phase. During locomotion on a horizontal branch, European red squirrels reduce speed and all substrate reaction forces transmitted may be due to the reduction of vertical oscillation of the center of mass. Further adjustments during locomotion on a horizontal branch differ significantly between trailing and leading forelimbs and include limb flexion, lead intervals, limb protraction and vertical displacement of the scapular pivot. Consequently, trailing and leading forelimbs perform different functions. Trailing forelimbs function primarily as shock-absorbing elements, whereas leading forelimbs are characterized by a high level of stiffness. This functional differentiation indicates that European red squirrels 'test' the substrate for stability with the trailing forelimb, while the leading forelimb responds to or counteracts swinging or snapping branches. Copyright © 2011 Elsevier GmbH. All rights reserved.

The use of climatic niches in screening procedures for introduced species to evaluate risk of spread: a case with the American Eastern grey squirrel.

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Mirko Di Febbraro

Full Text Available Species introduction represents one of the most serious threats for biodiversity. The realized climatic niche of an invasive species can be used to predict its potential distribution in new areas, providing a basis for screening procedures in the compilation of black and white lists to prevent new introductions. We tested this assertion by modeling the realized climatic niche of the Eastern grey squirrel Sciurus carolinensis. Maxent was used to develop three models: one considering only records from the native range (NRM, a second including records from native and invasive range (NIRM, a third calibrated with invasive occurrences and projected in the native range (RCM. Niche conservatism was tested considering both a niche equivalency and a niche similarity test. NRM failed to predict suitable parts of the currently invaded range in Europe, while RCM underestimated the suitability in the native range. NIRM accurately predicted both the native and invasive range. The niche equivalency hypothesis was rejected due to a significant difference between the grey squirrel's niche in native and invasive ranges. The niche similarity test yielded no significant results. Our analyses support the hypothesis of a shift in the species' climatic niche in the area of introductions. Species Distribution Models (SDMs appear to be a useful tool in the compilation of black lists, allowing identifying areas vulnerable to invasions. We advise caution in the use of SDMs based only on the native range of a species for the compilation of white lists for other geographic areas, due to the significant risk of underestimating its potential invasive range.

Home range, social behavior, and dominance relationships in the African unstriped ground squirrel, Xerus rutilus

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O'Shea, Thomas J.

1976-01-01

A field study of home range, social behavior, and dominance relationships in the African unstriped ground squirrel, Xerus rutilus, was conducted in semi-arid bushland near Kibwezi, Kenya. Ground squirrels lived alone or in small groups in isolated burrow systems and had broadly overlapping home ranges. They were neither territorial or colonial. Home ranges were estimated by visual observation of marked animals and those of males were considerably larger (mean=7.01 hectares (ha); n=4) than those of females (mean=1.37 ha; n-6). A continuum of agonistic behavior ranging from threat to combat is described, although actual combat was rarely observed. Sexual behavior includes a stereotypical tail display by adult males. Dominance relationships, based on 542 observed encounters between marked individuals, include a consistent male dominance over females and a fairly constant linear hierarchy among all individuals with shared home ranges. Similarities in the behavior of African ground squirrels and tree squirrels (Sciurus) are discussed.

Density of red squirrels and their use of non-native tree species in the Rogów Arboretum

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Krauze-Gryz Dagny

2016-03-01

Full Text Available The aim of the study was to compare the densities of red squirrel (Sciurus vulgaris in the arboretum and a neighbouring forest and to investigate which tree species the squirrels used. The study was conducted in the area of the Rogów Arboretum (53.76 ha and the so-called Zimna Woda and Wilczy Dół forest complexes (altogether 536 ha, all being part of an Experimental Forest Station in Rogów. The density of squirrels in the arboretum and the neighbouring forest was estimated and compared by means of snow tracks on transect routes. Changes in the abundance of squirrels throughout one year as well as their behaviour were determined on the basis of direct observations along transects running through the arboretum. More than half of the area of the arboretum was searched in order to record feeding signs of squirrels. Additionally, trees with bark stripping were recorded.

Kirsipuu (Prunus avium) : [luuletused] / R. W. Stedingh ; tlk. ja saatesõna: Jüri Talvet

Index Scriptorium Estoniae

Stedingh, R. W.

2003-01-01

Sisu: Kirsipuu (Prunus avium) ; Rubus spectabilis ; Rododendron (Rhododendron macrophyllum) ; Lysuchitum americanum ; Tulp (Tulipa gesneriana) ; Kanada hani (Branta canadensis) ; Metsorava pärastlõuna (Sciurus carolinensis) ; Ohakalind (Spinus tristis) ; Shakespeare'i mälestusmärk (kogust "Stanley pargi süit")

Do black-furred animals compensate for high solar absorption with smaller hairs? A test with a polymorphic squirrel species

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Melanie A. FRATTO, Andrew K. DAVIS

2011-12-01

Full Text Available In polymorphic mammalian species that display multiple color forms, those with dark, or melanic pelage would be prone to overheating, especially if they live in warm climates, because their fur absorbs solar energy at a higher rate. However, experimental studies indicate that certain physical properties of fur of dark individuals appear to prevent, or minimize heat stress, although it is not clear what properties do so. Here, we tested the possibility that black-furred individuals simply have shorter or thinner hair fibers, which would create a lighter (in terms of weight coat or one that allows greater air flow for evaporative coo- ling. We examined museum specimens of eastern fox squirrels Sciurus niger, a species native to the United States and one that displays brown, grey or all-black pelage color, and used image analysis procedures to quantify hairs from the dorsal surface and tail. From examination of 43 specimens (19 brown, 9 black and 15 grey, and 1,720 hairs, we found no significant difference in hair lengths across color morphs, but significant differences in hair fiber widths. Black squirrels had thinner body hairs than other forms (7% thinner, but thicker tail hairs (9% thicker than the others. Given that the dorsal surface would be directly exposed to solar radiation, we interpret this to be an adaptation to prevent heat stress during the day. The thicker tail hairs may be an adaptation for nighttime thermoregulation, since squirrels sleep with their tails wrapped around their bodies. These results add to a growing literature body of the functional significance of mammalian pelage [Current Zoology 57 (6: 731–736, 2011].

About some trematodes parasites of Haemulon sciurus (Shaw, 1803

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A. Kohn

1982-06-01

Full Text Available From September, 1980 to August, 1981 forty specimens of Haemulon sciurus from "Praia da Ribeira, Ilha do Governador", Rio de Janeiro State, were examined for parasites. In this paper, parcial results concerning only the collected trematodes are reported: Diplomonorchis leiostomi Hopkins, 1941 (first record in Brazil and in a new host; Lasiotocus beauforti (Hopkins, 1941 Thomas, 1959 (new host record; Genolopa ampullacea Linton, 1910; Parahemiurus merus (Linton, 1910 Yamaguti, 1938 (new host record: Aponurus pyriformis (Linton, 1910 Overstreet, 1973 and Diplangus paxillus Linton, 1910. Figures, measurements and comments of each species are given.De setembro, 1980 a agosto, 1981 foram examinados 40 exemplares de Haemulon sciurus, provenientes da Praia da Ribeira, Ilha do Governador, Estado do Rio de Janeiro. Neste trabalho são apresentados os resultados parciais, correspondentes aos trematodeos, grupo que apresentou maior ocorrência de parasitismo. As especies estudadas foram: Diplomonorchis leiostomi Hopkins, 1941 (primeira ocorrencia no Brasil e em novo hospedeiro; Lasiotocus beauforti (Hopkins, 1941 Thomas, 1959 (em novo hospedeiro; Genolopa ampullacea Linton, 1910; Parahemiurus merus (Linton, 1910 Yamaguti, 1938 (em um novo hospedeiro; Aponurus pyriformis (Linton, 1910 Overstreet, 1973 e Diplangus paxillus Linton, 1910. São apresentadas figuras, medidas e comentários.

50 CFR 17.84 - Special rules-vertebrates.

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 2 2010-10-01 2010-10-01 false Special rules-vertebrates. 17.84 Section 17.84 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR....84 Special rules—vertebrates. (a) Delmarva Peninsula fox squirrel (Sciurus niger cinereus). (1) The...

North American tree squirrels and ground squirrels with overlapping ranges host different Cryptosporidium species and genotypes

Czech Academy of Sciences Publication Activity Database

Stenger, B.L.S.; Clark, M.E.; Kváč, Martin; Khan, E.; Giddings, C.W.; Prediger, Jitka; McEvoy, J.M.

2015-01-01

Roč. 36, 2015-Dec (2015), s. 287-293 ISSN 1567-1348 R&D Projects: GA ČR GA15-01090S Institutional support: RVO:60077344 Keywords : Cryptosporidium * Tree squirrels * Ground squirrels * Host specificity * Zoonotic Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 2.591, year: 2015

Environmental Impact Research Program. Eastern Gray Squirrel (Sciurus carolinensis). Section 4.7.1, US Army Corps of Engineers Wildlife Resources Management Manual.

Science.gov (United States)

1986-07-01

Palmetto Sabal spp. Pawpaw Asimina triloba Pecan Carya illinoensis Persimmon Diospyros virginiana Pine Pinus app. Loblolly pine P. taeda Red mulberry...grandifotia Bitter pecan Carya aquatica Blackberry Rubus app. Black cherry Prunus serotina Blackgum Nyssa sylvatica Black walnut Jugtans nigra Blueberry...americana Hickory Carya Spp. Bitternut hickory C. cordiformis Shagbark hickory C. ovata Shellbark hickory C. Zaciniosa Hophornbeam Ostrya virginiana

Seasonal use of red-cockaded woodpecker cavities by southern flying squirrels.

Energy Technology Data Exchange (ETDEWEB)

Loeb, Susan C; Ruth, Deanna L

2004-12-31

Loeb, Susan C., and Deanna L. Ruth. 2004. Seasonal use of red-cockaded woodpecker cavities by southern flying squirrels. In: Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 8. Cavities, Cavity Trees, and Cavity Communities. Pp 501-502. Abstract: Southern flying squirrels can significantly impact red-cockaded woodpecker reproductive success (Laves and Loeb 1999). Thus exclusion or removal of flying squirrels from red-cockaded woodpecker cavities and clusters may be warranted in small woodpecker populations (U.S. Fish and Wildlife Service 2003). However, development of effective and efficient protocols for southern flying squirrel control requires an understanding of the seasonal dynamics of southern flying squirrel cavity use. Most studies of southern flying squirrel use of red-cockaded woodpecker cavities have been conducted during spring (e.g., Harlow and Lennartz 1983, Rudolph et al. 1990a, Loeb 1993) and no studies have examined the effects of long term flying squirrel control on subsequent cavity use. The objectives of this study were to determine: (1) whether flying squirrel use of red-cockaded woodpecker cavities varies with season or cavity type, and (2) the long term effect of continuous squirrel removal.

Variación cariológica en diferentes fenotipos de Sciurus granatensis (Rodentia, Sciuridae

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Marcos Nicolás Chacón Rojas

2007-01-01

de individuos con genomas diferentes en un población puede originar un proceso de depresión por exogamia o introgresión genética (pérdida de alelos adaptativos locales, procesos nocivos para la población receptora. Se estudiaron siete especímenes (cinco hembras y dos machos de S. granatensis procedentes del tráfico ilegal. Los cariotipos fueron obtenidos a partir de cultivos de linfocitos de sangre periférica. Las metafases con bandas G, R, C, Q y NOR, se analizaron al microscopio y se ordenaron en el programa Lucia Karyotyping®. Los individuos estudiados corresponden a los tres fenotipos reportados por Emmons LH, 1990, pero con una gran variación cariológica. Solo uno de los machos no corresponde a los fenotipos descritos, y además presenta varios rearreglos cromosómicos que lo diferencian notablemente de los demás, por lo cual posiblemente se trate de un híbrido estéril originado de dos poblaciones diferenciadas cariológicamente. El número de cromosomas fue constante (2n=42, con variación en el número fundamental (NF=80; 81, por lo cual se reportan tres cariomorfos para Sciurus granatensis, según NF y los rearreglos cromosómicos encontrados. Se observó variación en los pares 9, 16 y una translocación universal entre autosomas dentro de uno de los ejemplares. El cromosoma X es submetacéntrico mediano. El cromosoma Y es acrocéntrico, coincidente con lo descrito para Sciurus. No se registró una relación cariotipo-fenotipo. Por lo tanto se puede sugerir que Sciurus granatensis, es un complejo de especies con diferencias cariológicas y morfológicas que no ha sido estudiado a profundidad teniendo en cuenta su amplia distribución geográfica.

Red squirrel middens influence abundance but not diversity of other vertebrates.

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Erin E Posthumus

Full Text Available Some animals modify the environment in ways that can influence the resources available to other species. Because red squirrels (Tamiasciurus hudsonicus create large piles of conifer-cone debris (middens in which they store cones, squirrels concentrate resources that might affect biodiversity locally. To determine whether other animals are attracted to midden sites beyond their affinity for the same resources that attract red squirrels, we assessed associations between middens, mammals, and birds at population and community levels. We surveyed 75 middens where residency rates of red squirrels varied during the previous five years; sampling along this residency gradient permitted us to evaluate the influence of resources at middens beyond the influence of a resident squirrel. At each location, we quantified vegetation, landscape structure, abundance of conifer cones, and midden structure, and used capture-recapture, distance sampling, and remote cameras to quantify presence, abundance, and species richness of mammals and birds. Red squirrels and the resources they concentrated at middens influenced mammals and birds at the population scale and to a lesser extent at the community scale. At middens with higher residency rates of red squirrels, richness of medium and large mammals increased markedly and species richness of birds increased slightly. After accounting for local forest characteristics, however, only species richness of medium-to-large mammals was associated with a red squirrel being resident during surveys. In areas where red squirrels were resident during surveys or in areas with greater amounts of resources concentrated by red squirrels, abundances of two of four small mammal species and two of four bird species increased. We conclude that the presence of this ecosystem modifier and the resources it concentrates influence abundance of some mammals and birds, which may have implications for maintaining biodiversity across the wide

Assessing the Diversity of Rodent-Borne Viruses: exploring of high-throughput sequencing and classical amplification/sequencing approaches

Czech Academy of Sciences Publication Activity Database

Drewes, S.; Straková, Petra; Drexler, J. F.; Jacob, J.; Ulrich, R. G.

2017-01-01

Roč. 99, č. 4 (2017), s. 61-108 ISSN 0065-3527 Institutional support: RVO:68081766 Keywords : hepatitis-e virus * squirrels Sciurus-vulgaris * dependent DNA-polymerase * korean hemorrhagic-fever * beaver Castor-canadensis * mouse Micromys-minutus * rats Rattus-norvegicus * rous-sarcoma-virus * West-Nile-virus * population-cycles Subject RIV: EE - Microbiology, Virology OBOR OECD: Virology Impact factor: 4.243, year: 2016

Chemical Characterization, Antileishmanial Activity, and Cytotoxicity Effects of the Essential Oil from Leaves of Pluchea carolinensis (Jacq.) G. Don. (Asteraceae).

Science.gov (United States)

García, Marley; Scull, Ramón; Satyal, Prabodh; Setzer, William N; Monzote, Lianet

2017-09-01

Current strategies to control leishmaniasis are mainly based on chemotherapy. However, none of the available drugs can be considered to be ideal to treat this disease. Because of the hydrophobic nature and bioactivities of their components, essential oils (EOs) can be considered as important sources for developing agents against intracellular pathogens, such as Leishmania parasites. In this study, we report the chemical characterization, antileishmanial activities, and cytotoxicity effect of the EO from Pluchea carolinensis (Jacq.) G. Don. (Asteraceae). Chemical analysis revealed that EO from aerial part from P. carolinensis is composed of 44 compounds. The main component was selin-11-en-4α-ol, which made up 51.0%. In vitro antileishmanial studies showed that P. carolinensis EO inhibited the growth of promastigotes (IC 50  = 24.7 ± 7.1 μg/mL) and amastigotes (IC 50  = 6.2 ± 0.1 μg/mL) of Leishmania amazonensis, while cytotoxicity evaluation revealed fivefold higher values than those for the parasites. In a model of experimental cutaneous leishmaniasis in BALB/c mice, five doses of EO at 30 mg/kg by intralesional route demonstrated smaller lesion size and parasite burden (p < 0.05) compared with animals treated with Glucantime® and untreated mice. In conclusion, in vitro and in vivo results showed the potentialities of EO from P. carolinensis with the future possibility of a new alternative in the treatment for leishmaniasis. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Ground squirrel shooting and potential lead exposure in breeding avian scavengers

Science.gov (United States)

Herring, Garth; Eagles-Smith, Collin A.; Wagner, Mason T.

2016-01-01

Recreational ground squirrel shooting is a popular activity throughout the western United States and serves as a tool for managing ground squirrel populations in agricultural regions. Belding’s ground squirrels (Spermophilus beldingi) are routinely shot in California, Nevada, and Oregon across habitats that overlap with breeding avian scavengers. Ground squirrels shot with lead (Pb)-based bullets may pose a risk to avian scavengers if they consume carcasses containing Pb fragments. To assess the potential risk to breeding avian scavengers we developed a model to estimate the number, mass, and distribution of Pb fragments in shot ground squirrels using radiographic images. Eighty percent of shot carcasses contained detectible Pb fragments with an average of 38.6 mg of Pb fragments. Seven percent of all carcasses contained Pb fragment masses exceeding a lethal dose for a model raptor nestling (e.g. American kestrel Falco sparverius). Bullet type did not influence the number of fragments in shot ground squirrels, but did influence the mass of fragments retained. Belding’s ground squirrels shot with .17 Super Mag and unknown ammunition types contained over 28 and 17 times more mass of Pb fragments than those shot with .22 solid and .22 hollow point bullets, respectively. Ground squirrel body mass was positively correlated with both the number and mass of Pb fragments in carcasses, increasing on average by 76% and 56% respectively across the range of carcass masses. Although the mass of Pb retained in ground squirrel carcasses was small relative to the original bullet mass, avian scavenger nestlings that frequently consume shot ground squirrels may be at risk for Pb-induced effects (e.g., physiology, growth, or survival). Using modeling efforts we found that if nestling golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), and Swainson’s hawks (B. swainsoni) consumed shot ground squirrels proportionately to the nestling’s mass, energy needs

Ground Squirrel Shooting and Potential Lead Exposure in Breeding Avian Scavengers.

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Garth Herring

Full Text Available Recreational ground squirrel shooting is a popular activity throughout the western United States and serves as a tool for managing ground squirrel populations in agricultural regions. Belding's ground squirrels (Spermophilus beldingi are routinely shot in California, Nevada, and Oregon across habitats that overlap with breeding avian scavengers. Ground squirrels shot with lead (Pb-based bullets may pose a risk to avian scavengers if they consume carcasses containing Pb fragments. To assess the potential risk to breeding avian scavengers we developed a model to estimate the number, mass, and distribution of Pb fragments in shot ground squirrels using radiographic images. Eighty percent of shot carcasses contained detectible Pb fragments with an average of 38.6 mg of Pb fragments. Seven percent of all carcasses contained Pb fragment masses exceeding a lethal dose for a model raptor nestling (e.g. American kestrel Falco sparverius. Bullet type did not influence the number of fragments in shot ground squirrels, but did influence the mass of fragments retained. Belding's ground squirrels shot with .17 Super Mag and unknown ammunition types contained over 28 and 17 times more mass of Pb fragments than those shot with .22 solid and .22 hollow point bullets, respectively. Ground squirrel body mass was positively correlated with both the number and mass of Pb fragments in carcasses, increasing on average by 76% and 56% respectively across the range of carcass masses. Although the mass of Pb retained in ground squirrel carcasses was small relative to the original bullet mass, avian scavenger nestlings that frequently consume shot ground squirrels may be at risk for Pb-induced effects (e.g., physiology, growth, or survival. Using modeling efforts we found that if nestling golden eagles (Aquila chrysaetos, red-tailed hawks (Buteo jamaicensis, and Swainson's hawks (B. swainsoni consumed shot ground squirrels proportionately to the nestling's mass, energy

Influence of habitat on behavior of Towndsend's ground squirrels (Spermophilus townsendii)

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Sharpe, Peter B.; Van Horne, Beatrice

1998-01-01

Trade-offs between foraging and predator avoidance may affect an animal's survival and reproduction. These trade-offs may be influenced by differences in vegetative cover, especially if foraging profitability and predation risk differ among habitats. We examined above-ground activity of Townsend's ground squirrels (Spermophilus townsendii) in four habitats in the Snake River Birds of Prey National Conservation Area in southwestern Idaho to determine if behavior of ground squirrels varied among habitats, and we assessed factors that might affect perceived predation risk (i. e. predator detectability, predation pressure, population density). The proportion of time spent in vigilance by ground squirrels in winterfat (Krascheninnikovia lanata) and mosaic habitats of winterfat-sagebrush (Artemisia tridentata) was more than twice that of ground squirrels in burned and unburned sagebrush habitats. We found no evidence for the 'many-eyes' hypothesis as an explanation for differences in vigilance among habitats. Instead, environmental heterogeneity, especially vegetation structure, likely influenced activity budgets of ground squirrels. Differences in vigilance may have been caused by differences in predator detectability and refuge availability, because ground squirrels in the winterfat and mosaic habitats also spent more time in upright vigilant postures than ground squirrels in burned-sagebrush or sagebrush habitats. Such postures may enhance predator detection in low-growing winterfat.

Metabolism of lithocholic and chenodeoxycholic acids in the squirrel monkey

International Nuclear Information System (INIS)

Suzuki, H.; Hamada, M.; Kato, F.

1985-01-01

Metabolism of lithocholic acid (LCA) and chenodeoxycholic acid (CDCA) was studied in the squirrel monkey to clarify the mechanism of the lack of toxicity of CDCA in this animal. Radioactive LCA was administered to squirrel monkeys with biliary fistula. Most radioactivity was excreted in the bile in the form of unsulfated lithocholyltaurine. The squirrel monkey thus differs from humans and chimpanzees, which efficiently sulfate LCA, and is similar to the rhesus monkey and baboon in that LCA is poorly sulfated. When labeled CDCA was orally administered to squirrel monkeys, less than 20% of the dosed radioactivity was recovered as LCA and its further metabolites in feces over 3 days, indicating that bacterial metabolism of CDCA into LCA is strikingly less than in other animals and in humans. It therefore appears that LCA, known as a hepatotoxic secondary bile acid, is not accumulated in the squirrel monkey, not because of its rapid turnover through sulfation, but because of the low order of its production

Evolutionary history of tree squirrels (Rodentia, Sciurini) based on multilocus phylogeny reconstruction

Czech Academy of Sciences Publication Activity Database

Pečnerová, P.; Martínková, Natália

2012-01-01

Roč. 41, č. 3 (2012), s. 211-219 ISSN 0300-3256 Institutional research plan: CEZ:AV0Z60930519 Keywords : phylogeny * Sciurus * biogeography * colonisation Subject RIV: EG - Zoology Impact factor: 2.793, year: 2012

Demography of northern flying squirrels informs ecosystem management of western interior forests.

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John F. Lehmkuhl; Keith D. Kistler; James S. Begley; John. Boulanger

2006-01-01

We studied northern flying squirrel (Glaucomys sabrinus) demography in the eastern Washington Cascade Range to test hypotheses about regional and local abundance patterns and to inform managers of the possible effects of fire and fuels management on flying squirrels. We quantified habitat characteristics and squirrel density, population trends, and...

Texas ratsnake predation on southern flying squirrels in red-cockaded woodpecker cavities

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D. Craig Rudolph; Richard R. Schaefer; Josh B. Pierce; Dan Saenz; Richard N. Conner

2009-01-01

Elaphe spp. (ratsnakes) are frequent predators on cavity-nesting birds and other vertebrates, including Glaucomys volans (Southern Flying Squirrels). They are known predators of Picoides borealis (Red-cockaded Woodpeckers), especially during the nestling phase. Picoides borealis cavities are frequently occupied by Southern Flying Squirrels, often several squirrels per...

Histological Studies of Some Organs of Squirrels ( Xerus erythropus ...

African Journals Online (AJOL)

Histological Studies of Some Organs of Squirrels ( Xerus erythropus ) in Tropical Ecological Zone. ... The ground squirrels were trapped using rodent traps, anesthetized identified to species level and dissected to expose the viscera. The organs (liver brain, heart, gonads (testes and ovaries) were dissected out, clean off ...

Avian nestling predation by endangered Mount Graham red squirrel

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Claire A. Zugmeyer; John L. Koprowski

2007-01-01

Studies using artificial nests or remote cameras have documented avian predation by red squirrels (Tamiasciurus hudsonicus). Although several direct observations of avian predation events are known in the northern range of the red squirrel distribution, no accounts have been reported in the southern portion. We observed predation upon a hermit thrush...

Caching behaviour by red squirrels may contribute to food conditioning of grizzly bears

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Julia Elizabeth Put

2017-08-01

Full Text Available We describe an interspecific relationship wherein grizzly bears (Ursus arctos horribilis appear to seek out and consume agricultural seeds concentrated in the middens of red squirrels (Tamiasciurus hudsonicus, which had collected and cached spilled grain from a railway. We studied this interaction by estimating squirrel density, midden density and contents, and bear activity along paired transects that were near (within 50 m or far (200 m from the railway. Relative to far ones, near transects had 2.4 times more squirrel sightings, but similar numbers of squirrel middens. Among 15 middens in which agricultural products were found, 14 were near the rail and 4 subsequently exhibited evidence of bear digging. Remote cameras confirmed the presence of squirrels on the rail and bears excavating middens. We speculate that obtaining grain from squirrel middens encourages bears to seek grain on the railway, potentially contributing to their rising risk of collisions with trains.

Object permanence in orangutans (Pongo pygmaeus) and squirrel monkeys (Saimiri sciureus).

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de Blois, S T; Novak, M A; Bond, M

1998-06-01

The authors tested orangutans (Pongo pygmaeus) and squirrel monkeys (Saimiri sciureus) on object permanence tasks. In Experiment 1, orangutans solved all visible displacements and most invisible displacements except those involving movements into 2 boxes successively. In Experiment 2, performance of orangutans on double invisible displacements and control displacements (assessing simple strategies) was compared. Orangutans did not use the simple strategy of selecting the box visited last by the experimenter. Instead, poorer performance on double invisible displacements may have been related to increased memory requirements. In Experiment 3, squirrel monkeys were tested using the procedure of Experiment 1. Squirrel monkeys solved visible but did not comprehend invisible displacements. Results suggest that orangutans but not squirrel monkeys possess Stage 6 object permanence capabilities.

Cytogenetic investigations in Sciurus anomalus from Turkish Thrace (Rodentia: Sciuridae)

Czech Academy of Sciences Publication Activity Database

Arslan, A.; Zima, Jan

2012-01-01

Roč. 64, č. 4 (2012), s. 421-426 ISSN 0324-0770 Institutional support: RVO:68081766 Keywords : karyotype * C-banding * Ag-NOR staining * Caucasian squirrel * Turkey Subject RIV: EG - Zoology Impact factor: 0.309, year: 2012 http://www.acta-zoologica-bulgarica.eu/downloads/acta-zoologica-bulgarica/2012/64-4-421-426.pdf

Data from camera surveys identifying co-occurrence and occupancy linkages between fishers (Pekania pennanti, rodent prey, mesocarnivores, and larger predators in mixed-conifer forests

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Rick A. Sweitzer

2016-03-01

Full Text Available These data provide additional information relevant to the frequency of fisher detections by camera traps, and single-season occupancy and local persistence of fishers in small patches of forest habitats detailed elsewhere, “Landscape Fuel Reduction, Forest Fire, and Biophysical Linkages to Local Habitat Use and Local Persistence of Fishers (Pekania pennanti in Sierra Nevada Mixed-conifer Forests” [10]. The data provides insight on camera trap detections of 3 fisher predators (bobcat [Lynx rufus]. Coyote [Canis latrans], mountain lion [Puma concolor], 5 mesocarnivores in the same foraging guild as fishers (gray fox [Urocyon cinereoargenteus] ringtail [Bassariscus astutus], marten [Martes americana], striped skunk [Mephitis mephitis] spotted skunk [Spilogale gracilis], and 5 Sciuridae rodents that fishers consume as prey (Douglas squirrel [Tamiasciurus douglasii], gray squirrel [Sciurus griseus], northern flying squirrel [Glaucomys sabrinus], long-eared chipmunk [Neotamias quadrimaculatus], California ground squirrel [Spermophilus beecheyi]. We used these data to identify basic patterns of co-occurrence with fishers, and to evaluate the relative importance of presence of competing mesocarnivores, rodent prey, and predators for fisher occupancy of small, 1 km2 grid cells of forest habitat. Keywords: Carnivores, Competition, Distribution, Foraging guild, Predation, Tree squirrels

Cystic Calculus in a Laboratory-housed Green Anole (Anolis carolinensis).

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Birke, Leslie L; Cespedes, Ann M; Schachner, Emma R; Lailvaux, Simon P

2017-03-01

An adult, male, wild-caught, laboratory-housed green anole (Anolis carolinensis) on a locomotor performance study was presented for anorexia. The anole exhibited a 26% weight loss and a thin body condition but was otherwise alert and active. Despite supportive care, the anole's clinical condition deteriorated, necessitating euthanasia. Postmortem examination revealed a 4.5 mm × 2.5-mm cystic calculus, which consisted entirely of sodium urate. Here we describe the clinical findings and locomotor consequences of this disease in a green anole. Although urolithiasis has been reported clinically in reptiles, this report presents the first case of a cystic calculus in a laboratory-housed green anole.

Responses of squirrel monkeys to their experimentally modified mobbing calls

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Fichtel, Claudia; Hammerschmidt, Kurt

2003-05-01

Previous acoustic analyses suggested emotion-correlated changes in the acoustic structure of squirrel monkey (Saimiri sciureus) vocalizations. Specifically, calls given in aversive contexts were characterized by an upward shift in frequencies, often accompanied by an increase in amplitude. In order to test whether changes in frequencies or amplitude are indeed relevant for conspecific listeners, playback experiments were conducted in which either frequencies or amplitude of mobbing calls were modified. Latency and first orienting response were measured in playback experiments with six adult squirrel monkeys. After broadcasting yaps with increased frequencies or amplitude, squirrel monkeys showed a longer orienting response towards the speaker than after the corresponding control stimuli. Furthermore, after broadcasting yaps with decreased frequencies or amplitude, squirrel monkeys showed a shorter orienting response towards the speaker than after the corresponding manipulated calls with higher frequencies or amplitude. These results suggest that changes in frequencies or amplitude were perceived by squirrel monkeys, indicating that the relationship between call structure and the underlying affective state of the caller agreed with the listener's assessment of the calls. However, a simultaneous increase in frequencies and amplitude did not lead to an enhanced response, compared to each single parameter. Thus, from the receiver's perspective, both call parameters may mutually replace each other.

Novel Hepatozoon in vertebrates from the southern United States.

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Allen, Kelly E; Yabsley, Michael J; Johnson, Eileen M; Reichard, Mason V; Panciera, Roger J; Ewing, Sidney A; Little, Susan E

2011-08-01

Novel Hepatozoon spp. sequences collected from previously unrecognized vertebrate hosts in North America were compared with documented Hepatozoon 18S rRNA sequences in an effort to examine phylogenetic relationships between the different Hepatozoon organisms found cycling in nature. An approximately 500-base pair fragment of 18S rDNA common to Hepatozoon spp. and some other apicomplexans was amplified and sequenced from the tissues or blood of 16 vertebrate host species from the southern United States, including 1 opossum (Didelphis virginiana), 2 bobcats (Lynx rufus), 1 domestic cat (Felis catus), 3 coyotes (Canis latrans), 1 gray fox (Urocyon cinereoargenteus), 4 raccoons (Procyon lotor), 1 pet boa constrictor (Boa constrictor imperator), 1 swamp rabbit (Sylvilagus aquaticus), 1 cottontail rabbit (Sylvilagus floridanus), 4 woodrats (Neotoma fuscipes and Neotoma micropus), 3 white-footed mice (Peromyscus leucopus), 8 cotton rats (Sigmodon hispidus), 1 cotton mouse (Peromyscus gossypinus), 1 eastern grey squirrel (Sciurus carolinensis), and 1 woodchuck (Marmota monax). Phylogenetic analyses and comparison with sequences in the existing database revealed distinct groups of Hepatozoon spp., with clusters formed by sequences obtained from scavengers and carnivores (opossum, raccoons, canids, and felids) and those obtained from rodents. Surprisingly, Hepatozoon spp. sequences from wild rabbits were most closely related to sequences obtained from carnivores (97.2% identical), and the sequence from the boa constrictor was most closely related to the rodent cluster (97.4% identical). These data are consistent with recent work identifying prey-predator transmission cycles in Hepatozoon spp. and suggest this pattern may be more common than previously recognized.

Nest trees of northern flying squirrels in the Sierra Nevada

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Marc D. Meyer; Douglas A. Kelt; Malcolm P. North

2005-01-01

We examined the nest-tree preferences of northern flying squirrels (Glaucomys sabrinus) in an old-growth, mixed-conifer and red fir (Abies magnifica) forest of the southern Sierra Nevada of California. We tracked 27 individuals to 122 nest trees during 3 summers. Flying squirrels selected nest trees that were larger in diameter and...

Seed Removal Increased by Scramble Competition with an Invasive Species.

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Minor, Rebecca L; Koprowski, John L

2015-01-01

Competition for seeds has a major influence on the evolution of granivores and the plants on which they rely. The complexity of interactions and coevolutionary relationships vary across forest types. The introduction of non-native granivores has considerable potential to alter seed dispersal dynamics. Non-native species are a major cause of endangerment for native species, but the mechanisms are often unclear. As biological invasions continue to rise, it is important to understand mechanisms to build up strategies to mitigate the threat. Our field experiment quantified the impact of introduced Abert's squirrels (Sciurus aberti) on rates of seed removal within the range of critically endangered Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis), which consumes similar foods. In the presence of invasive Abert's squirrels, the time cones were removed was faster than when the invasive was excluded, accounting for a median removal time of cones available to red and Abert's squirrels that is 32.8% less than that of cones available only to the rare native red squirrels. Moreover, in the presence of Abert's squirrels, removal rates are higher at great distance from a territorial red squirrel larderhoard and in more open portions of the forest, which suggests differential patterns of seed dispersal. The impact on food availability as a result of cone removal by Abert's squirrels suggests the potential of food competition as a mechanism of endangerment for the Mount Graham red squirrel. Furthermore, the magnitude and differential spatial patterns of seed removal suggest that non-native granivores may have impacts on forest regeneration and structure.

Seed Removal Increased by Scramble Competition with an Invasive Species.

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Rebecca L Minor

Full Text Available Competition for seeds has a major influence on the evolution of granivores and the plants on which they rely. The complexity of interactions and coevolutionary relationships vary across forest types. The introduction of non-native granivores has considerable potential to alter seed dispersal dynamics. Non-native species are a major cause of endangerment for native species, but the mechanisms are often unclear. As biological invasions continue to rise, it is important to understand mechanisms to build up strategies to mitigate the threat. Our field experiment quantified the impact of introduced Abert's squirrels (Sciurus aberti on rates of seed removal within the range of critically endangered Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis, which consumes similar foods. In the presence of invasive Abert's squirrels, the time cones were removed was faster than when the invasive was excluded, accounting for a median removal time of cones available to red and Abert's squirrels that is 32.8% less than that of cones available only to the rare native red squirrels. Moreover, in the presence of Abert's squirrels, removal rates are higher at great distance from a territorial red squirrel larderhoard and in more open portions of the forest, which suggests differential patterns of seed dispersal. The impact on food availability as a result of cone removal by Abert's squirrels suggests the potential of food competition as a mechanism of endangerment for the Mount Graham red squirrel. Furthermore, the magnitude and differential spatial patterns of seed removal suggest that non-native granivores may have impacts on forest regeneration and structure.

Kleptoparasitic behavior and species richness at Mt. Graham red squirrel middens

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Andrew J. Edelman; John L. Koprowski; Jennifer L. Edelman

2005-01-01

We used remote photography to assess the frequency of inter- and intra-specific kleptoparasitism and species richness at Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis) middens. Remote cameras and conifer cones were placed at occupied and unoccupied middens, and random sites. Species richness of small mammals was higher at red squirrel...

The Autopsy of Squirrel Doe

Science.gov (United States)

Dick, Timothy T.; Watson, Jason

2005-01-01

Introductory biology laboratory experiences frequently rely on preserved chordates for anatomical study. Unfortunately, these preserved organisms rarely reflect the appearance of a living creature. Since community colleges are generally prohibited the use of live chordates, this paper describes the autopsy of a "road kill" squirrel to facilitate…

Red-cockaded woodpecker cavity tree resin avoidance by southern flying squirrels

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Richard R. Schaefer; Daniel Saenz

1998-01-01

While examining red-cockaded woodpecker (Picoides borealis) cavity contents in eastern Texas, the authors observed cavity tree resin avoidance by southern flying squirrels (Glaucomys volans). The tree surface around an active red-cockaded woodpecker cavity is coated with sticky resin which flows from resin wells created by the woodpecker. The southern flying squirrel...

Multiplex PCR assay discriminates rabbit, rat and squirrel meat in food chain.

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Ahamad, Mohammad Nasir Uddin; Ali, Md Eaqub; Hossain, M A Motalib; Asing, Asing; Sultana, Sharmin; Jahurul, M H A

2017-12-01

Rabbit meat is receiving increasing attention because it contains a high level of proteins with relatively little fat. On the other hand, squirrel meat is served in upper-class meals in certain countries, so is sold at higher prices. The other side of the coin is rat meat, which has family ties with rabbit and squirrel but poses substantial threats to public health because it is a potential carrier of several zoonotic organisms. Recently, rat meat was mislabelled and sold as lamb after chemical modification. Thus, the chances of rabbit and squirrel meat substitution by rat meat cannot be ruled out. For the first time, a multiplex PCR assay was developed in Malaysia for the discriminatory identification of rat, rabbit and squirrel in the food chain. Rabbit (123 bp), rat (108 bp) and squirrel (243 bp) targets were amplified from ATP6 and cytb genes, along with a eukaryotic internal control (141bp). The products were sequenced and cross-tested against 22 species. A total of 81 reference samples and 72 meatball specimens were screened to validate the assay. Analyte stability was evaluated through boiling, autoclaving and micro-oven cooking. The tested lower limits of detection were 0.01 ng DNA for pure meat and 0.1% for meatballs.

Fox squirrels match food assessment and cache effort to value and scarcity.

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Mikel M Delgado

Full Text Available Scatter hoarders must allocate time to assess items for caching, and to carry and bury each cache. Such decisions should be driven by economic variables, such as the value of the individual food items, the scarcity of these items, competition for food items and risk of pilferage by conspecifics. The fox squirrel, an obligate scatter-hoarder, assesses cacheable food items using two overt movements, head flicks and paw manipulations. These behaviors allow an examination of squirrel decision processes when storing food for winter survival. We measured wild squirrels' time allocations and frequencies of assessment and investment behaviors during periods of food scarcity (summer and abundance (fall, giving the squirrels a series of 15 items (alternating five hazelnuts and five peanuts. Assessment and investment per cache increased when resource value was higher (hazelnuts or resources were scarcer (summer, but decreased as scarcity declined (end of sessions. This is the first study to show that assessment behaviors change in response to factors that indicate daily and seasonal resource abundance, and that these factors may interact in complex ways to affect food storing decisions. Food-storing tree squirrels may be a useful and important model species to understand the complex economic decisions made under natural conditions.

Management and conservation of tree squirrels: the importance of endemism, species richness, and forest condition

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John L. Koprowski

2005-01-01

Tree squirrels are excellent indicators of forest health yet the taxon is understudied. Most tree squirrels in the Holarctic Region are imperiled with some level of legal protection. The Madrean Archipelago is the epicenter for tree squirrel diversity in North America with 5 endemic species and 2 introduced species. Most species of the region are poorly studied in...

Comparative expression of the four enamel matrix protein genes, amelogenin, ameloblastin, enamelin and amelotin during amelogenesis in the lizard Anolis carolinensis.

Science.gov (United States)

Gasse, Barbara; Sire, Jean-Yves

2015-01-01

In a recent study, we have demonstrated that amelotin (AMTN) gene structure and its expression during amelogenesis have changed during tetrapod evolution. Indeed, this gene is expressed throughout enamel matrix deposition and maturation in non-mammalian tetrapods, while in mammals its expression is restricted to the transition and maturation stages of amelogenesis. Previous studies of amelogenin (AMEL) gene expression in a lizard and a salamander have shown similar expression pattern to that in mammals, but to our knowledge there are no data regarding ameloblastin (AMBN) and enamelin (ENAM) expression in non-mammalian tetrapods. The present study aims to look at, and compare, the structure and expression of four enamel matrix protein genes, AMEL, AMBN, ENAM and AMTN during amelogenesis in the lizard Anolis carolinensis. We provide the full-length cDNA sequence of A. carolinensis AMEL and AMBN, and show for the first time the expression of ENAM and AMBN in a non-mammalian species. During amelogenesis in A. carolinensis, AMEL, AMBN and ENAM expression in ameloblasts is similar to that described in mammals. It is noteworthy that AMEL and AMBN expression is also found in odontoblasts. Our findings indicate that AMTN is the only enamel matrix protein gene that is differentially expressed in ameloblasts between mammals and sauropsids. Changes in AMTN structure and expression could be the key to explain the structural differences between mammalian and reptilian enamel, i.e. prismatic versus non-prismatic.

Environmental Impact Statement for BOMARC Missile Site, McGuire AFB, New Jersey. Volume 3. Methodology Development. Appendices 3-1 through 3-8

Science.gov (United States)

1992-05-01

wild, but are extant in cultivation . It is likely that some of these will not warrant listing, while others will be found to be in greater danger of...region (North-West Italy). Journal of Environmental Radioactivity 5:71-81. Connell, D.W., and Miller, G.J., 1984. Chemistry and Ecotoxicology of...Rare in most of the Pine Region, but occasional in cultivated areas near towns. Gray Squirrel (Sciarus carolinensis) Occasional throughout the Pine

Mandible shape and dwarfism in squirrels (Mammalia, Rodentia): interaction of allometry and adaptation

Science.gov (United States)

Hautier, Lionel; Fabre, Pierre-Henri; Michaux, Jacques

2009-06-01

Squirrels include several independent lineages of dwarf forms distributed into two ecological groups: the dwarf tree and flying squirrels. The mandible of dwarf tree squirrels share a highly reduced coronoid process and a condylar process drawn backwards. Dwarf flying squirrels on the other hand, have an elongated coronoid process and a well-differentiated condylar process. To interpret such a difference, Elliptic Fourier Transform was used to evaluate how mandible shape varies with dwarfism in sciurids. The results obtained show that this clear-cut difference cannot be explained by a simple allometric relationship in relation with size decrease. We concluded that the retention of anteriorly positioned eye sockets, in relation with distance estimation, allowed the conservation of a well-differentiated coronoid process in all flying species, despite the trend towards its reduction observed among sciurids as their size decreases.

A brain MRI atlas of the common squirrel monkey, Saimiri sciureus

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Gao, Yurui; Schilling, Kurt G.; Khare, Shweta P.; Panda, Swetasudha; Choe, Ann S.; Stepniewska, Iwona; Li, Xia; Ding, Zhoahua; Anderson, Adam; Landman, Bennett A.

2014-03-01

The common squirrel monkey, Saimiri sciureus, is a New World monkey with functional and microstructural organization of central nervous system similar to that of humans. It is one of the most commonly used South American primates in biomedical research. Unlike its Old World macaque cousins, no digital atlases have described the organization of the squirrel monkey brain. Here, we present a multi-modal magnetic resonance imaging (MRI) atlas constructed from the brain of an adult female squirrel monkey. In vivo MRI acquisitions include high resolution T2 structural imaging and low resolution diffusion tensor imaging. Ex vivo MRI acquisitions include high resolution T2 structural imaging and high resolution diffusion tensor imaging. Cortical regions were manually annotated on the co-registered volumes based on published histological sections.

Behavioural correlates of urbanisation in the Cape ground squirrel Xerus inauris

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Chapman, Tarryn; Rymer, Tasmin; Pillay, Neville

2012-11-01

Urbanisation critically threatens biodiversity because of habitat destruction and novel selection pressures. Some animals can respond to these challenges by modifying their behaviour, particularly anti-predator behaviour, allowing them to persist in heavily transformed urban areas. We investigated whether the anti-predator behaviour of the Cape ground squirrel Xerus inauris differed in three localities that differed in their level of urbanisation. According to the habituation hypothesis, we predicted that ground squirrels in urban areas would: (a) be less vigilant and forage more; (b) trade-off flight/vigilance in favour of foraging; and (c) have shorter flight initiation distances (FID) when approached by a human observer. Observations were made in winter and summer at each locality. As expected, ground squirrels in urbanised areas were less vigilant and had shorter FIDs but did not trade-off between foraging and vigilance. In contrast, a population in a non-urbanised locality showed greater levels of vigilance, FID and traded-off vigilance and foraging. A population in a peri-urban locality showed mixed responses. Our results indicate that Cape ground squirrels reduce their anti-predator behaviour in urban areas and demonstrate a flexible behavioural response to urbanisation.

Who's your neighbor? Acoustic cues to individual identity in red squirrel Tamiasciurus hudsonicus rattle calls

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Shannon M. DIGWEED, Drew RENDALL, Teana IMBEAU

2012-10-01

Full Text Available North American red squirrels Tamiasciurus hudsonicus often produce a loud territorial rattle call when conspecifics enter or invade a territory. Previous playback experiments suggest that the territorial rattle call may indicate an invader's identity as squirrels responded more intensely to calls played from strangers than to calls played from neighbors. This dear-enemy effect is well known in a variety of bird and mammal species and functions to reduce aggressive interactions between known neighbors. However, although previous experiments on red squirrels suggest some form of individual differentiation and thus recognition, detailed acoustic analysis of potential acoustic cues in rattle calls have not been conducted. If calls function to aid in conspecific identification in order to mitigate aggressive territorial interactions, we would expect that individual recognition cues would be acoustically represented. Our work provides a detailed analysis of acoustic cues to identity within rattle calls. A total of 225 calls across 32 individual squirrels from Sheep River Provincial Park, Kananaskis, AB, Canada, were analyzed with discriminant function analysis for potential acoustic cues to individual identity. Initial analysis of all individuals revealed a reliable acoustic differentiation across individuals. A more detailed analysis of clusters of neighboring squirrels was performed and results again indicated a statistically significant likelihood that calls were assigned correctly to specific squirrels (55%-75% correctly assigned; in other words squirrels have distinct voices that should allow for individual identification and discrimination by conspecifics [Current Zoology 58 (5: 758–764, 2012].

Striatal dopamine D2/3 receptor regulation by stress inoculation in squirrel monkeys

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Alex G. Lee

2016-06-01

Full Text Available Intermittent mildly stressful situations provide opportunities to learn, practice, and improve coping in a process called stress inoculation. Stress inoculation also enhances cognitive control and response inhibition of impulsive motivated behavior. Cognitive control and motivation have been linked to striatal dopamine D2 and/or D3 receptors (DRD2/3 in rodents, monkeys, and humans. Here, we study squirrel monkeys randomized early in life to stress inoculation with or without maternal companionship and a no-stress control treatment condition. Striatal DRD2/3 availability in adulthood was measured in vivo by [11C]raclopride binding using positron emission tomography (PET. DRD2/3 availability was greater in caudate and putamen compared to ventral striatum as reported in PET studies of humans and other non-human primates. DRD2/3 availability in ventral striatum was also consistently greater in stress inoculated squirrel monkeys compared to no-stress controls. Squirrel monkeys exposed to stress inoculation in the presence of their mother did not differ from squirrel monkeys exposed to stress inoculation without maternal companionship. Similar effects in different social contexts extend the generality of our findings and together suggest that stress inoculation increases striatal DRD2/3 availability as a correlate of cognitive control in squirrel monkeys.

Nesting and feeding habits of Indian giant squirrel (Ratufa indica in Karlapat wildlife sanctuary, India

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Pradhan, A. K.

2017-01-01

Full Text Available The Indian giant squirrel (Ratufa indica is one of four species of giant squirrels in the world. It is endemic to India and its populations are severely fragmented. The ecology of squirrels in Asia has been little studied, hindering conservation and management efforts. We studied the Indian giant squirrel’s nesting and feeding habits during spring in the Karlapat Wildlife Sanctuary, India. We surveyed 122.5 km of natural trails for direct observation of these squirrels, their nests and feeding evidence, and we sampled plot–based quadrats to assess the availability of resources. We used Manly’s resource selection function and log–likelihood test ratios to analyse the data for preference. The mean encounter rate of the Indian giant squirrel was 0.57 (± 0.18 SD individuals/km. Haldinia cordifolia (Wi = 4.899, p < 0.001 and Mangifera indica (Wi = 4.322, p = 0.001 were the preferred tree for nesting, whereas Xylia xylocarpa (31.30% and Bauhinia vahlii (28.24% were the most commonly eaten plants. Nest site preference was for taller tree species. As current management practices directly damage the preferred nesting sites and food resources, our findings aim to promote effective conservation of the Indian giant squirrel.

Habitat and Landscape Correlates of Southern Flying Squirrel Use of Red-Cockaded Woodpecker Clusters

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Susan C. Loeb; Shawna L. Reid; Donald J. Lipscomb

2012-01-01

Southern flying squirrels (Glaucomys volans) can have significant negative impacts on redcockaded woodpecker (Picoides borealis) reproductive success and group size. Although direct control of southern flying squirrels may be necessary in small red-cockaded woodpecker populations (

Equivalence Between Squirrel Cage and Sheet Rotor Induction Motor

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Dwivedi, Ankita; Singh, S. K.; Srivastava, R. K.

2016-06-01

Due to topological changes in dual stator induction motor and high cost of its fabrication, it is convenient to replace the squirrel cage rotor with a composite sheet rotor. For an experimental machine, the inner and outer stator stampings are normally available whereas the procurement of rotor stampings is quite cumbersome and is not always cost effective. In this paper, the equivalence between sheet/solid rotor induction motor and squirrel cage induction motor has been investigated using layer theory of electrical machines, so as to enable one to utilize sheet/solid rotor in dual port experimental machines.

Evidence that a Highway Reduces Apparent Survival Rates of Squirrel Gliders

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Sarah C. McCall

2010-09-01

Full Text Available Roads and traffic are prominent components of most landscapes throughout the world, and their negative effects on the natural environment can extend for hundreds or thousands of meters beyond the road. These effects include mortality of wildlife due to collisions with vehicles, pollution of soil and air, modification of wildlife behavior in response to noise, creation of barriers to wildlife movement, and establishment of dispersal conduits for some plant and animal species. In southeast Australia, much of the remaining habitat for the squirrel glider, Petaurus norfolcensis, is located in narrow strips of Eucalyptus woodland that is adjacent to roads and streams, as well as in small patches of woodland vegetation that is farther from roads. We evaluated the effect of traffic volume on squirrel gliders by estimating apparent annual survival rates of adults along the Hume Freeway and nearby low-traffic-volume roads. We surveyed populations of squirrel gliders by trapping them over 2.5 years, and combined these data with prior information on apparent survival rates in populations located away from freeways to model the ratio of apparent annual survival rates in both site types. The apparent annual survival rate of adult squirrel gliders living along the Hume Freeway was estimated to be approximately 60% lower than for squirrel gliders living near local roads. The cause of the reduced apparent survival rate may be due to higher rates of mortality and/or higher emigration rates adjacent to the Hume Freeway compared with populations near smaller country roads. Management options for population persistence will be influenced by which of these factors is the primary cause of a reduced apparent survival rate.

Differential Effects of Roads and Traffic on Space Use and Movements of Native Forest-Dependent and Introduced Edge-Tolerant Species.

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Hsiang Ling Chen

Full Text Available Anthropogenic infrastructure such as roads and non-native species are major causes of species endangerment. Understanding animal behavioral responses to roads and traffic provides insight into causes and mechanisms of effects of linear development on wildlife and aids effective mitigation and conservation. We investigated effects of roads and traffic on space use and movements of two forest-dwelling species: endemic, forest-dependent Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis and introduced, edge-tolerant Abert's squirrels (Sciurus aberti. To assess the effects of roads on space use and movement patterns, we compared the probability that a squirrel home range included roads and random lines in forests, and assessed effects of traffic intensity on rate of road crossing and movement patterns. Red squirrels avoided areas adjacent to roads and rarely crossed roads. In contrast, Abert's squirrels were more likely to include roads in their home ranges compared to random lines in forests. Both red squirrels and Abert's squirrels increased speed when crossing roads, compared to before and after road crossings. Increased hourly traffic volume reduced the rate of road crossings by both species. Behavioral responses of red squirrels to roads and traffic resemble responses to elevated predation risk, including reduced speed near roads and increased tortuosity of movement paths with increased traffic volume. In contrast, Abert's squirrels appeared little affected by roads and traffic with tortuosity of movement paths reduced as distance to roads decreased. We found that species with similar body size category (<1 kg but different habitat preference and foraging strategy responded to roads differently and demonstrated that behavior and ecology are important when considering effects of roads on wildlife. Our results indicate that roads restricted movements and space use of a native forest-dependent species while creating habitat preferred

Differential Effects of Roads and Traffic on Space Use and Movements of Native Forest-Dependent and Introduced Edge-Tolerant Species.

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Chen, Hsiang Ling; Koprowski, John L

2016-01-01

Anthropogenic infrastructure such as roads and non-native species are major causes of species endangerment. Understanding animal behavioral responses to roads and traffic provides insight into causes and mechanisms of effects of linear development on wildlife and aids effective mitigation and conservation. We investigated effects of roads and traffic on space use and movements of two forest-dwelling species: endemic, forest-dependent Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis) and introduced, edge-tolerant Abert's squirrels (Sciurus aberti). To assess the effects of roads on space use and movement patterns, we compared the probability that a squirrel home range included roads and random lines in forests, and assessed effects of traffic intensity on rate of road crossing and movement patterns. Red squirrels avoided areas adjacent to roads and rarely crossed roads. In contrast, Abert's squirrels were more likely to include roads in their home ranges compared to random lines in forests. Both red squirrels and Abert's squirrels increased speed when crossing roads, compared to before and after road crossings. Increased hourly traffic volume reduced the rate of road crossings by both species. Behavioral responses of red squirrels to roads and traffic resemble responses to elevated predation risk, including reduced speed near roads and increased tortuosity of movement paths with increased traffic volume. In contrast, Abert's squirrels appeared little affected by roads and traffic with tortuosity of movement paths reduced as distance to roads decreased. We found that species with similar body size category (roads differently and demonstrated that behavior and ecology are important when considering effects of roads on wildlife. Our results indicate that roads restricted movements and space use of a native forest-dependent species while creating habitat preferred by an introduced, edge-tolerant species.

Mining online genomic resources in Anolis carolinensis facilitates rapid and inexpensive development of cross-species microsatellite markers for the Anolis lizard genus.

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Wordley, Claire; Slate, Jon; Stapley, Jessica

2011-01-01

Online sequence databases can provide valuable resources for the development of cross-species genetic markers. In particular, mining expressed tag sequences (EST) for microsatellites and developing conserved cross-species microsatellite markers can provide a rapid and relatively inexpensive method to develop new markers for a range of species. Here, we adopt this approach to develop cross-species microsatellite markers in Anolis lizards, which is a model genus in evolutionary biology and ecology. Using EST sequences from Anolis carolinensis, we identified 127 microsatellites that satisfied our criteria, and tested 49 of these in five species of Anolis (carolinensis, distichus, apletophallus, porcatus and sagrei). We identified between 8 and 25 new variable genetic markers for five Anolis species. These markers will be a valuable resource for studies of population genetics, comparative mapping, mating systems, behavioural ecology and adaptive radiations in this diverse lineage. © 2010 Blackwell Publishing Ltd.

Modelling recolonization of second-growth forest stands by the north american red squirrel Tamiasciurus hudsonicus.

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Nyquist, B; Tyson, R; Larsen, K

2007-05-01

In this paper, we present a model for source-sink population dynamics where the locations of source and sink habitats change over time. We do this in the context of the population dynamics of the North American red squirrel, Tamiasciurus hudsonicus, within a forest environment subject to harvesting and regrowth. Harvested patches of forest are initially sinks, then eventually become source habitat again as the forest regrows. At the same time, each harvested patch is gradually recolonized by squirrels from other forest patches. We are interested in the interaction of forest harvesting dynamics with squirrel population dynamics. This depends on the harvesting schedule, and on the choices squirrels make when deciding whether to settle in a mature forest patch or in a recently harvested patch. We find that the time it takes for a second-growth forest patch to be recolonized at the mature forest level is longer than the time required for the habitat quality to be restored to the mature forest level. We also notice that recolonization pressure decreases squirrel populations in neighbouring patches. The connectivity between forest patches and the cutting schedule used also affect the time course of recolonization and steady-state population levels.

Cup tool use by squirrel monkeys.

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Buckmaster, Christine L; Hyde, Shellie A; Parker, Karen J; Lyons, David M

2015-12-01

Captive-born male and female squirrel monkeys spontaneously 'invented' a cup tool use technique to Contain (i.e., hold and control) food they reduced into fragments for consumption and to Contain water collected from a valve to drink. Food cup use was observed more frequently than water cup use. Observations indicate that 68% (n = 39/57) of monkeys in this population used a cup (a plastic slip cap) to Contain food, and a subset of these monkeys, 10% (n = 4/39), also used a cup to Contain water. Cup use was optional and did not replace, but supplemented, the hand/arm-to-mouth eating and direct valve drinking exhibited by all members of the population. Strategies monkeys used to bring food and cups together for food processing activity at preferred upper-level perching areas, in the arboreal-like environment in which they lived, provides evidence that monkeys may plan food processing activity with the cups. Specifically, prior to cup use monkeys obtained a cup first before food, or obtained food and a cup from the floor simultaneously, before transporting both items to upper-level perching areas. After food processing activity with cups monkeys rarely dropped the cups and more often placed the cups onto perching. Monkeys subsequently returned to use cups that they previously placed on perching after food processing activity. The latter behavior is consistent with the possibility that monkeys may keep cups at preferred perching sites for future food processing activity and merits experimental investigation. Reports of spontaneous tool use by squirrel monkeys are rare and this is the first report of population-level tool use. These findings offer insights into the cognitive abilities of squirrel monkeys and provide a new context for behavior studies with this genus and for comparative studies with other primates. © 2015 Wiley Periodicals, Inc.

Laboratory evaluation of anticoagulant-treated baits for control of the northern palm squirrel, Funambulus pennanti Wroughton.

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Mathur, R. P.; Prakash, I.

1980-01-01

Individually caged northern palm squirrels, Funambulus pennanti, were fed with bait containing 0.025% warfarin or fumarin, 0.0075% chlorophacinone or 0.005% brodifacoum for a fixed number of days varying from 1 to 14. Brodifacoum (WBA 8119) was found most toxic since 66% and 70% of the animals died after one and two days' feeding respectively. Chlorophacinone killed 70% of the squirrels after three days' feeding. Squirrels were relatively tolerant to warfarin and fumarin since the mortality a...

Ca2+ cycling in heart cells from ground squirrels: adaptive strategies for intracellular Ca2+ homeostasis.

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Xiao-Chen Li

Full Text Available Heart tissues from hibernating mammals, such as ground squirrels, are able to endure hypothermia, hypoxia and other extreme insulting factors that are fatal for human and nonhibernating mammals. This study was designed to understand adaptive mechanisms involved in intracellular Ca(2+ homeostasis in cardiomyocytes from the mammalian hibernator, ground squirrel, compared to rat. Electrophysiological and confocal imaging experiments showed that the voltage-dependence of L-type Ca(2+ current (I(Ca was shifted to higher potentials in ventricular myocytes from ground squirrels vs. rats. The elevated threshold of I(Ca did not compromise the Ca(2+-induced Ca(2+ release, because a higher depolarization rate and a longer duration of action potential compensated the voltage shift of I(Ca. Both the caffeine-sensitive and caffeine-resistant components of cytosolic Ca(2+ removal were more rapid in ground squirrels. Ca(2+ sparks in ground squirrels exhibited larger amplitude/size and much lower frequency than in rats. Due to the high I(Ca threshold, low SR Ca(2+ leak and rapid cytosolic Ca(2+ clearance, heart cells from ground squirrels exhibited better capability in maintaining intracellular Ca(2+ homeostasis than those from rats and other nonhibernating mammals. These findings not only reveal adaptive mechanisms of hibernation, but also provide novel strategies against Ca(2+ overload-related heart diseases.

A meta-analysis of forest age and structure effects on northern flying squirrel densities

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Gillian L. Holloway; Winston P. Smith

2011-01-01

Research on the impact of clearcut logging and partial harvesting practices on northern flying squirrels (Glaucomys sabrinus) has shown inconsistent and contrary results, limiting the use of this species as a management indicator species. Much of this variability in study results is due to the labor intensive nature of studying flying squirrels,...

Consequences of artic ground squirrels on soil carbon loss from Siberian tundra

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Golden, N. A.; Natali, S.; Zimov, N.

2014-12-01

A large pool of organic carbon (C) has been accumulating in the Arctic for thousands of years. Much of this C has been frozen in permafrost and unavailable for microbial decomposition. As the climate warms and permafrost thaws, the fate of this large C pool will be driven not only by climatic conditions, but also by ecosystem changes brought about by arctic animal populations. In this project we studied arctic ground squirrels (Spermophilus parryii), which are widely-distributed throughout the Arctic. These social mammals create subterranean burrows that mix soil layers, increase aeration, alter soil moisture and temperature, and redistribute soil nutrients, all of which may impact microbial decomposition. We examined the effects of arctic ground squirrel activity on soil C mineralization in dry heath tundra underlain by continuous permafrost in the Kolyma River watershed in northeast Siberia, Russia. Vegetation cover was greatly reduced on the ground squirrel burrows (80% of ground un-vegetated), compared to undisturbed sites (35% of ground un-vegetated). Soils from ground squirrel burrows were also significantly dryer and warmer. To examine effects of ground squirrel activity on microbial respiration, we conducted an 8-day incubation of soil fromburrows and from adjacent undisturbed tundra. In addition, we assessed the impact of nutrient addition by including treatments with low and high levels of nitrogen addition. Microbial respiration (per gram soil) was three-fold higher in incubated soils from the undisturbed sites compared to soils collected from the burrows. The lower rates of respiration from the disturbed soils may have been a result of lower carbon quality or low soil moisture. High nitrogen addition significantly increased respiration in the undisturbed soils, but not in the disturbed burrow soils, which suggests that microbial respiration in the burrow soils was not primarily limited by nitrogen. These results demonstrate the importance of wildlife

Laboratory evaluation of anticoagulant-treated baits for control of the northern palm squirrel, Funambulus pennanti Wroughton.

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Mathur, R P; Prakash, I

1980-12-01

Individually caged northern palm squirrels, Funambulus pennanti, were fed with bait containing 0.025% warfarin or fumarin, 0.0075% chlorophacinone or 0.005% brodifacoum for a fixed number of days varying from 1 to 14. Brodifacoum (WBA 8119) was found most toxic since 66% and 70% of the animals died after one and two days' feeding respectively. Chlorophacinone killed 70% of the squirrels after three days' feeding. Squirrels were relatively tolerant to warfarin and fumarin since the mortality after a period of 14 days' feeding was only 58% and 75% respectively.

Thinning of young Douglas-fir forests decreases density of northern flying squirrels in the Oregon Cascades

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Manning, Tom; Hagar, Joan C.; McComb, Brenda C.

2012-01-01

Large-scale commercial thinning of young forests in the Pacific Northwest is currently promoted on public lands to accelerate the development of late-seral forest structure for the benefit of wildlife species such as northern spotted owls (Strix occidentalis caurina) and their prey, including the northern flying squirrel (Glaucomys sabrinus). Attempts to measure the impact of commercial thinning on northern flying squirrels have mostly addressed short-term effects (2–5 years post-thinning) and the few published studies of longer-term results have been contradictory. We measured densities of northern flying squirrels 11–13 years after thinning of young (55–65 years) Douglas-fir forest stands in the Cascade Range of Oregon, as part of the Young Stand Thinning & Diversity Study. The study includes four replicate blocks, each consisting of an unthinned control stand and one stand each of the following thinning treatments: Heavy Thin; Light Thin; and Light Thin with Gaps. Thinning decreased density of northern flying squirrels, and squirrel densities were significantly lower in heavily thinned stands than in more lightly thinned stands. Regression analysis revealed a strong positive relationship of flying squirrel density with density of large (>30 cm diameter) standing dead trees and a negative relationship with percent cover of low understory shrubs. Maintaining sufficient area and connectivity of dense, closed canopy forest is recommended as a strategy to assure that long-term goals of promoting late-seral structure do not conflict with short-term habitat requirements of this important species.

Seasonal, spatial, and maternal effects on gut microbiome in wild red squirrels.

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Ren, Tiantian; Boutin, Stan; Humphries, Murray M; Dantzer, Ben; Gorrell, Jamieson C; Coltman, David W; McAdam, Andrew G; Wu, Martin

2017-12-21

Our understanding of gut microbiota has been limited primarily to findings from human and laboratory animals, but what shapes the gut microbiota in nature remains largely unknown. To fill this gap, we conducted a comprehensive study of gut microbiota of a well-studied North American red squirrel (Tamiasciurus hudsonicus) population. Red squirrels are territorial, solitary, and live in a highly seasonal environment and therefore represent a very attractive system to study factors that drive the temporal and spatial dynamics of gut microbiota. For the first time, this study revealed significant spatial patterns of gut microbiota within a host population, suggesting limited dispersal could play a role in shaping and maintaining the structure of gut microbial communities. We also found a remarkable seasonal rhythm in red squirrel's gut microbial composition manifested by a tradeoff between relative abundance of two genera Oscillospira and Corpococcus and clearly associated with seasonal variation in diet availability. Our results show that in nature, environmental factors exert a much stronger influence on gut microbiota than host-associated factors including age and sex. Despite strong environmental effects, we found clear evidence of individuality and maternal effects, but host genetics did not seem to be a significant driver of the gut microbial communities in red squirrels. Taken together, the results of this study emphasize the importance of external ecological factors rather than host attributes in driving temporal and spatial patterns of gut microbiota in natural environment.

Energetic costs of performance in trained and untrained Anolis carolinensis lizards.

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Lailvaux, Simon P; Wang, Andrew Z; Husak, Jerry F

2018-03-12

The energetic costs of performance constitute a non-trivial component of animals' daily energetic budgets. However, we currently lack an understanding of how those costs are partitioned among the various stages of performance development, maintenance, and production. We manipulated individual investment in performance by training Anolis carolinensis lizards for endurance or sprinting ability. We then measured energetic expenditure both at rest and immediately following exercise to test whether such training alters the maintenance and production costs of performance. Trained lizards had lower resting metabolic rates than controls, suggestive of a maintenance saving associated with enhanced performance as opposed to a cost. Production costs also differed, with sprint-trained lizards incurring the largest energetic performance cost and experiencing the longest recovery times compared to endurance trained and control animals. Although performance training modifies metabolism, production costs are probably the key drivers of trade-offs between performance and other life-history traits in this species. © 2018. Published by The Company of Biologists Ltd.

The adaptive function of masturbation in a promiscuous African ground squirrel.

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Waterman, Jane M

2010-09-28

Studies of animal mating systems increasingly emphasize female multiple mating and cryptic sexual selection, particularly sperm competition. Males under intense sperm competition may manipulate sperm quantity and quality through masturbation, which could waste sperm and decrease fertility. I examined the factors influencing masturbation by male Cape ground squirrels (Xerus inauris) in light of a number of functional hypotheses. Observational data on a marked population of squirrels were collected in east-central Namibia using scan and all-occurrences sampling. Masturbation was far more frequent on days of female oestrus and mostly occurred after copulation. Masturbation rates were higher in dominant males, which copulate more, than in subordinates and increased with number of mates a female accepts. These results suggest that masturbation in this species was not a response to sperm competition nor a sexual outlet by subordinates that did not copulate. Instead masturbation could function as a form of genital grooming. Female Cape ground squirrels mate with up to 10 males in a 3-hr oestrus, and by masturbating after copulation males could reduce the chance of infection. Sexually transmitted infections (STIs) can profoundly affect fertility, and their consequences for mating strategies need to be examined more fully.

Ecological scale and forest development: squirrels, dietary fungi, and vascular plants in managed and unmanaged forests.

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A.B. Carey; J. Kershner; B. Biswell; L.S. Dominguez de Toledo

1999-01-01

Understanding ecological processes and their spatial scales is key to managing ecosystems for biodiversity, especially for species associated with late-seral forest. We focused on 2 species of squirrel (Sciuridae: northern flying squirrel, Glaucomys sabrinus, and Townsend's chipmunk, Tamias townsendii) in a crosssectional survey of managed and natural stands in...

Note on breeding and parental care behaviours of albino Hoary-bellied Squirrel Callosciurus pygerythrus (Rodentia: Sciuridae in Sibsagar District of Assam, India

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G. Kalita

2009-06-01

Full Text Available A few individuals of albino Horay-bellied Squirrels along with normal gray individuals of Callosciurus pygerythrus have been observed in Sibsagar district of Assam, India. One albino female was studied in captivity. This paper presents our observations on the breeding behaviour and the parental care exhibited by the albino squirrel in captivity. The squirrel bred twice in captivity with a normal male of the same species. In both the periods, a single male baby with normal coat colour developed. Oral dose of vitamin E has been found helpful in the breeding of the studied squirrel species. The mother squirrel exhibited parental care by carrying her baby using her mouth, to a safer place during danger. However, the observed phenomenon is unlike that of the cat species. Some of the habitat ecology and feeding habits of the albino squirrels have also been studied, both in natural and in captive conditions.

Cryptosporidium rubeyi n. sp. (Apicomplexa: Cryptosporidiidae in multiple Spermophilus ground squirrel species

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Xunde Li

2015-12-01

Full Text Available Previously we reported the unique Cryptosporidium sp. “c” genotype (e.g., Sbey03c, Sbey05c, Sbld05c, Sltl05c from three species of Spermophilus ground squirrel (Spermophilus beecheyi, Spermophilus beldingi, Spermophilus lateralis located throughout California, USA. This follow-up work characterizes the morphology and animal infectivity of this novel genotype as the final step in proposing it as a new species of Cryptosporidium. Analysis of sequences of 18S rRNA, actin, and HSP70 genes of additional Cryptosporidium isolates from recently sampled California ground squirrels (S. beecheyi confirms the presence of the unique Sbey-c genotype in S. beecheyi. Phylogenetic and BLAST analysis indicates that the c-genotype in Spermophilus ground squirrels is distinct from Cryptosporidium species/genotypes from other host species currently available in GenBank. We propose to name this c-genotype found in Spermophilus ground squirrels as Cryptosporidium rubeyi n. sp. The mean size of C. rubeyi n. sp. oocysts is 4.67 (4.4–5.0 μm × 4.34 (4.0–5.0 μm, with a length/width index of 1.08 (n = 220. Oocysts of C. rubeyi n. sp. are not infectious to neonatal BALB/c mice and Holstein calves. GenBank accession numbers for C. rubeyi n. sp. are DQ295012, AY462233, and KM010224 for the 18S rRNA gene, KM010227 for the actin gene, and KM010229 for the HSP70 gene.

A comparison of habitat use and demography of red squirrels at the southern edge of their range

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Katherine M. Leonard; John L. Koprowski

2009-01-01

Populations at the edge of their geographic range may demonstrate different population dynamics from central populations. Endangered Mt. Graham red squirrels (Tamiasciurus hudsonicus grahamensis), endemic to southeastern Arizona, represent the southernmost red squirrel population and are found at lower densities than conspecifics in the center of the...

Modulation of immunity in young-adult and aged squirrel, Funambulus pennanti by melatonin and p-chlorophenylalanine

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Singh Rajesh

2009-04-01

Full Text Available Abstract Background Our interest was to find out whether pineal gland and their by melatonin act as modulator of immunosenescence. Parachlorophenylalanine (PCPA – a β adrenergic blocker, is known to perform chemical pinealectomy (Px by suppressing indirectly the substrate 5-hydroxytryptamine (5-HT for melatonin synthesis and thereby melatonin itself. The role of PCPA, alone and in combination with melatonin was recorded in immunomodulation and free radical load in spleen of young adult and aged seasonal breeder Indian palm squirrel Funambulus pennanti. Results Aged squirrel presented reduced immune parameters (i.e. total leukocyte count (TLC, Lymphocytes Count (LC, % stimulation ratio of splenocytes (% SR against T cell mitogen concanavalin A (Con A, delayed type hypersensitivity (DTH to oxazolone when compared to young adult group. Melatonin administration (25 μg/100 g body mass/day significantly increased the immune parameters in aged more than the young adult squirrel while PCPA administration (4.5 mg/100 g body mass/day reduced all the immune parameters more significantly in young than aged. Combination of PCPA and melatonin significantly increased the immune parameters to the normal control level of both the age groups. TBARS level was significantly high in aged than the young group. PCPA treatment increased TBARS level of young and aged squirrels both while melatonin treatment decreased it even than the controls. Nighttime peripheral melatonin level was low in control aged group than the young group. Melatonin injection at evening hours significantly increased the peripheral level of nighttime melatonin, while combined injection of PCPA and melatonin brought it to control level in both aged and young adult squirrels. Conclusion PCPA suppressed immune status more in aged than in adult by reducing melatonin level as it did chemical Px. Melatonin level decreased in control aged squirrels and so there was a decrease in immune parameters

The adaptive function of masturbation in a promiscuous African ground squirrel.

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Jane M Waterman

Full Text Available BACKGROUND: Studies of animal mating systems increasingly emphasize female multiple mating and cryptic sexual selection, particularly sperm competition. Males under intense sperm competition may manipulate sperm quantity and quality through masturbation, which could waste sperm and decrease fertility. I examined the factors influencing masturbation by male Cape ground squirrels (Xerus inauris in light of a number of functional hypotheses. METHODOLOGY: Observational data on a marked population of squirrels were collected in east-central Namibia using scan and all-occurrences sampling. FINDINGS: Masturbation was far more frequent on days of female oestrus and mostly occurred after copulation. Masturbation rates were higher in dominant males, which copulate more, than in subordinates and increased with number of mates a female accepts. CONCLUSIONS: These results suggest that masturbation in this species was not a response to sperm competition nor a sexual outlet by subordinates that did not copulate. Instead masturbation could function as a form of genital grooming. Female Cape ground squirrels mate with up to 10 males in a 3-hr oestrus, and by masturbating after copulation males could reduce the chance of infection. Sexually transmitted infections (STIs can profoundly affect fertility, and their consequences for mating strategies need to be examined more fully.

Effects of new forest management strategies on squirrel populations.

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Andrew B. Carey

2000-01-01

Two strategies for managing forests for multiple values have achieved prominence in debates in the Pacific Northwest: (1) legacy retention with passive management and long rotations, and (2) intensive management for timber with commercial thinnings and long rotations. Northern flying squirrels (Glaucomys sabrinus), Townsend's chipmunks (

Osteology of Carnufex carolinensis (Archosauria: Psuedosuchia from the Pekin Formation of North Carolina and Its Implications for Early Crocodylomorph Evolution.

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Susan M Drymala

Full Text Available Crocodylomorphs originated in the Late Triassic and were the only crocodile-line archosaurs to survive the end-Triassic extinction. Recent phylogenetic analyses suggest that the closest relatives of these generally gracile, small-bodied taxa were a group of robust, large-bodied predators known as rauisuchids implying a problematic morphological gap between early crocodylomorphs and their closest relatives. Here we provide a detailed osteological description of the recently named early diverging crocodylomorph Carnufex carolinensis from the Upper Triassic Pekin Formation of North Carolina and assess its phylogenetic position within the Paracrocodylomorpha. Carnufex displays a mosaic of crocodylomorph, rauisuchid, and dinosaurian characters, as well as highly laminar cranial elements and vertebrae, ornamented dermal skull bones, a large, subtriangular antorbital fenestra, and a reduced forelimb. A phylogenetic analysis utilizing a comprehensive dataset of early paracrocodylomorphs and including seven new characters and numerous modifications to characters culled from the literature recovers Carnufex carolinensis as one of the most basal members of Crocodylomorpha, in a polytomy with two other large bodied taxa (CM 73372 and Redondavenator. The analysis also resulted in increased resolution within Crocodylomorpha and a monophyletic clade containing the holotype and two referred specimens of Hesperosuchus as well as Dromicosuchus. Carnufex occupies a key transition at the origin of Crocodylomorpha, indicating that the morphology typifying early crocodylomorphs appeared before the shift to small body size.

Effect of environmental enrichment devices on behaviors of single- and group-housed squirrel monkeys (Saimiri sciureus)

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Spring, S. E.; Clifford, J. O.; Tomko, D. L.

1997-01-01

Squirrel monkeys display an interest in novel places, habituate to new situations, and spend most of their daily activity in the wild in large groups engaging in feeding behaviors over a broad area. Captivity limits these behaviors and consequently may disrupt normal social organizations. In captivity, squirrel monkeys may exhibit stereotypical behaviors that are believed to indicate decreased psychologic well-being. When a monkey's behavior can be made to approach that seen in the wild, and stereotypical behaviors are minimal, it is assumed that psychologic well-being is adequate. Environmental enrichment devices have been used to address the Animal Welfare Act requirement that psychologic well-being of captive nonhuman primates be considered. The purpose of the study reported here was to examine whether various environmental enrichment devices improve the psychologic well-being of captive squirrel monkeys. In the study, we used behavioral observation to quantify the effectiveness of several environmental enrichment devices for reducing stereotypical behaviors in squirrel monkeys housed alone or in groups. Analysis of our results revealed that the environmental enrichment devices did not affect the expression of normal or stereotypical behaviors, but that the type of housing did.

Combining a dispersal model with network theory to assess habitat connectivity.

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Lookingbill, Todd R; Gardner, Robert H; Ferrari, Joseph R; Keller, Cherry E

2010-03-01

Assessing the potential for threatened species to persist and spread within fragmented landscapes requires the identification of core areas that can sustain resident populations and dispersal corridors that can link these core areas with isolated patches of remnant habitat. We developed a set of GIS tools, simulation methods, and network analysis procedures to assess potential landscape connectivity for the Delmarva fox squirrel (DFS; Sciurus niger cinereus), an endangered species inhabiting forested areas on the Delmarva Peninsula, USA. Information on the DFS's life history and dispersal characteristics, together with data on the composition and configuration of land cover on the peninsula, were used as input data for an individual-based model to simulate dispersal patterns of millions of squirrels. Simulation results were then assessed using methods from graph theory, which quantifies habitat attributes associated with local and global connectivity. Several bottlenecks to dispersal were identified that were not apparent from simple distance-based metrics, highlighting specific locations for landscape conservation, restoration, and/or squirrel translocations. Our approach links simulation models, network analysis, and available field data in an efficient and general manner, making these methods useful and appropriate for assessing the movement dynamics of threatened species within landscapes being altered by human and natural disturbances.

Age determination in the bush squirrel, Paraxerus cepapi cepapi ...

African Journals Online (AJOL)

Tooth eruption and wear, measurements of skulls, eye-lens mass determination and different aspects of phallic morphology were used in an attempt at age classification in the bush squirrel, Paraxerus c. cepapi. The first method proved the most practical and allowed for three immature and three adult age classes.

Effects of drought and prolonged winter on Townsend's ground squirrel demography in shrubsteppe habitats

Science.gov (United States)

Van Horne, Beatrice; Olson, Gail S.; Schooley, Robert L.; Corn, Janelle G.; Burnham, Kenneth P.

1997-01-01

During a mark–recapture study of Townsend's ground squirrels (Spermophilus townsendii) on 20 sites in the Snake River Birds of Prey National Conservation Area, Idaho, in 1991 through 1994, 4407 animals were marked in 17639 capture events. This study of differences in population dynamics of Townsend's ground squirrels among habitats spanned a drought near the extreme of the 130-yr record, followed by prolonged winter conditions.Townsend's ground squirrels have a short active season (≈4 mo) in which to reproduce and store fat for overwintering. Their food consists largely of succulent grasses and forbs in this dry shrubsteppe and grassland habitat. The drought in the latter half of the 1992 active season produced early drying of Sandberg's bluegrass (Poa secunda) and was associated with low adult and juvenile body masses prior to immergence into estivation/hibernation. The following prolonged winter was associated with late emergence of females in 1993. Early-season body masses of adults were low in 1993 relative to 1992, whereas percentage of body fat in males was relatively high. These weather patterns in spring 1992 and winter 1993 also resulted in reduced adult persistence through the ≈7-mo inactive period, especially for adult females, and near-zero persistence of >1200 juveniles. Consequently, densities of Townsend's ground squirrels across the 20 livetrap sites declined.The demographic effects of drought and prolonged winter lasted at least through the subsequent breeding season. Adult females that survived these weather extremes produced fewer emergent young per female than did adult females prior to the event. Prior to the drought/prolonged winter, yearling female body masses were higher than, or indistinguishable from, those of adults. Females produced in 1993 had lower body masses as yearlings than did adult females.Demographic response to the drought and prolonged winter varied with habitat; ground squirrels in sagebrush habitat showed less decline

Predictive habitat models derived from nest-box occupancy for the endangered Carolina northern flying squirrel in the southern Appalachians

Science.gov (United States)

W. Mark Ford; Andrew M. Evans; Richard H. Odom; Jane L. Rodrigue; Christine A. Kelly; Nicole Abaid; Corinne A. Diggins; Douglas Newcomb

2015-01-01

In the southern Appalachians, artificial nest-boxes are used to survey for the endangered Carolina northern flying squirrel (CNFS; Glaucomys sabrinus coloratus), a disjunct subspecies associated with high elevation (>1385 m) forests. Using environmental parameters diagnostic of squirrel habitat, we created 35 a priori occupancy...

Shape optimization of 3D curved slots and its application to the squirrel-cage elastic support design

Science.gov (United States)

Wang, Dan; Zhang, Weihong; Wang, Zhenpei; Zhu, Jihong

2010-10-01

The squirrel-cage elastic support is one of the most important components of an aero-engine rotor system. A proper structural design will favor the static and dynamic performances of the system. In view of the deficiency of the current shape optimization techniques, a new mapping approach is proposed to define shape design variables based on the parametric equations of 3D curves and surfaces. It is then applied for the slot shape optimization of a squirrel-cage elastic support. To this end, an automatic design procedure that integrates the Genetic Algorithm (GA) is developed to solve the problem. Two typical examples with different shape constraints are considered. Numerical results provide reasonable optimum designs for the improvement of stiffness and strength of the squirrel-cage elastic support.

Effects of low temperature on breathing pattern and ventilatory responses during hibernation in the golden-mantled ground squirrel.

Science.gov (United States)

Webb, Cheryl L; Milsom, William K

2017-07-01

During entrance into hibernation in golden-mantled ground squirrels (Callospermophilus lateralis), ventilation decreases as metabolic rate and body temperature fall. Two patterns of respiration occur during deep hibernation. At 7 °C body temperature (T b ), a breathing pattern characterized by episodes of multiple breaths (20.6 ± 1.9 breaths/episode) separated by long apneas or nonventilatory periods (T nvp ) (mean = 11.1 ± 1.2 min) occurs, while at 4 °C T b , a pattern in which breaths are evenly distributed and separated by a relatively short T nvp (0.5 ± 0.05 min) occurs. Squirrels exhibiting each pattern have similar metabolic rates and levels of total ventilation (0.2 and 0.23 ml O 2 /hr/kg and 0.11 and 0.16 ml air/min/kg, respectively). Squirrels at 7 °C T b exhibit a significant hypoxic ventilatory response, while squirrels at 4 °C T b do not respond to hypoxia at any level of O 2 tested. Squirrels at both temperatures exhibit a significant hypercapnic ventilatory response, but the response is significantly reduced in the 4 °C T b squirrels. Carotid body denervation has little effect on the breathing patterns or on the hypercapnic ventilatory responses. It does reduce the magnitude and threshold for the hypoxic ventilatory response. Taken together the data suggest that (1) the fundamental rhythm generator remains functional at low temperatures; (2) the hypercapnic ventilatory response arises from central chemoreceptors that remain functional at very low temperatures; (3) the hypoxic ventilatory response arises from both carotid body and aortic chemoreceptors that are silenced at lower temperatures; and (4) there is a strong correlation between breathing pattern and chemosensitivity.

A Squirrel Cage Type Electric Motor Rotor Assembly.

Science.gov (United States)

1996-09-05

cage motor, but also provides efficiencies approaching those of permanent magnet motors . With the above and other objects in view, as will...and active motor life relative to known permanent magnet motors . Referring to FIG. 4, there is illustrated an alternative embodiment in which...part the.known advantages of a squirrel cage motor, and further provides improved efficiencies approaching those of permanent magnet motors . It is to

Borrelia carolinensis sp. nov., a new (14th) member of the Borrelia burgdorferi Sensu Lato complex from the southeastern region of the United States

Czech Academy of Sciences Publication Activity Database

Rudenko, Natalia; Golovchenko, Maryna; Grubhoffer, Libor; Oliver, J. H., Jr.

2009-01-01

Roč. 47, č. 1 (2009), s. 134-141 ISSN 0095-1137 R&D Projects: GA MŠk(CZ) LC06009; GA ČR(CZ) GA524/06/1479 Institutional research plan: CEZ:AV0Z60220518 Keywords : multilocus sequence analysis * B. burgdorferi sl complex * new borrelia species * Borrelia carolinensis Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 4.162, year: 2009

Borrelia carolinensis sp. nov., a novel species of the Borrelia burgclorferi sensu lato complex isolated from rodents and a tick from the south-eastern USA

Czech Academy of Sciences Publication Activity Database

Rudenko, Natalia; Golovchenko, Maryna; Grubhoffer, Libor; Oliver, J. H., Jr.

2011-01-01

Roč. 61, č. 2 (2011), 381-383 ISSN 1466-5026 R&D Projects: GA MŠk(CZ) LC06009; GA ČR GA206/09/1782 Institutional research plan: CEZ:AV0Z60220518 Keywords : MULTILOCUS SEQUENCE-ANALYSIS * FRAGMENT-LENGTH-POLYMORPHISM * LYME -DISEASE * RIBOSOMAL-RNA * Borrelia carolinensis sp. nov. * phylogeny Subject RIV: EE - Microbiology, Virology Impact factor: 2.268, year: 2011

Tail function during arboreal quadrupedalism in squirrel monkeys (Saimiri boliviensis) and tamarins (Saguinus oedipus).

Science.gov (United States)

Young, Jesse W; Russo, Gabrielle A; Fellmann, Connie D; Thatikunta, Meena A; Chadwell, Brad A

2015-10-01

The need to maintain stability on narrow branches is often presented as a major selective force shaping primate morphology, with adaptations to facilitate grasping receiving particular attention. The functional importance of a long and mobile tail for maintaining arboreal stability has been comparatively understudied. Tails can facilitate arboreal balance by acting as either static counterbalances or dynamic inertial appendages able to modulate whole-body angular momentum. We investigate associations between tail use and inferred grasping ability in two closely related cebid platyrrhines-cotton-top tamarins (Saguinus oedipus) and black-capped squirrel monkeys (Saimiri boliviensis). Using high-speed videography of captive monkeys moving on 3.2 cm diameter poles, we specifically test the hypothesis that squirrel monkeys (characterized by grasping extremities with long digits) will be less dependent on the tail for balance than tamarins (characterized by claw-like nails, short digits, and a reduced hallux). Tamarins have relatively longer tails than squirrel monkeys, move their tails through greater angular amplitudes, at higher angular velocities, and with greater angular accelerations, suggesting dynamic use of tail to regulate whole-body angular momentum. By contrast, squirrel monkeys generally hold their tails in a comparatively stationary posture and at more depressed angles, suggesting a static counterbalancing mechanism. This study, the first empirical test of functional tradeoffs between grasping ability and tail use in arboreal primates, suggests a critical role for the tail in maintaining stability during arboreal quadrupedalism. Our findings have the potential to inform our functional understanding of tail loss during primate evolution. © 2015 Wiley Periodicals, Inc.

Autoshaping and automaintenance of a key-press response in squirrel monkeys.

Science.gov (United States)

Gamzu, E; Schwam, E

1974-03-01

Following exposure for a minimum of 500 to 600 trials, three of four naive squirrel monkeys eventually pressed a response key, illumination of which always preceded delivery of a food pellet. Three other naive monkeys did not press the key when the pellets were delivered randomly with respect to key illumination. Despite some similarities to autoshaping using pigeons, the data indicate many points of difference when squirrel monkeys are used as subjects. Although key-food pairings were shown to be important in the acquisition of the key-press response, they were ineffective in maintaining the response when either a negative response-reinforcer dependency was introduced, or when there was no scheduled response-reinforcer dependency (fixed trial). Not all demonstrations of autoshaping can be considered to be under the control of those processes that are primarily responsible for the phenomena obtained in pigeons.

Determination of an optimal dose of medetomidine-ketamine-buprenorphine for anaesthesia in the Cape ground squirrel (Xerus inauris

Directory of Open Access Journals (Sweden)

K. E. Joubert

2011-04-01

Full Text Available The optimal dose of medetomidine-ketamine-buprenorphine was determined in 25 Cape ground squirrels (Xerus inauris undergoing surgical implantation of a temperature logger into the abdominal cavity. At the end of anaesthesia, the squirrels were given atipamezole intramuscularly to reverse the effects of medetomidine. The mean dose of medetomidine was 67.6±9.2 μg/kg, ketamine 13.6±1.9 mg/kg and buprenorphine 0.5±0.06 μg/kg. Induction time was 3.1 ± 1.4 min. This produced surgical anaesthesia for 21± 4.2 min. Atipamezole 232±92 μg/kg produced a rapid recovery. Squirrels were sternally recumbent in 3.5 ± 2.2 min.

Conservatism and adaptability during squirrel radiation: what is mandible shape telling us?

Directory of Open Access Journals (Sweden)

Isaac Casanovas-Vilar

Full Text Available Both functional adaptation and phylogeny shape the morphology of taxa within clades. Herein we explore these two factors in an integrated way by analyzing shape and size variation in the mandible of extant squirrels using landmark-based geometric morphometrics in combination with a comparative phylogenetic analysis. Dietary specialization and locomotion were found to be reliable predictors of mandible shape, with the prediction by locomotion probably reflecting the underlying diet. In addition a weak but significant allometric effect could be demonstrated. Our results found a strong phylogenetic signal in the family as a whole as well as in the main clades, which is in agreement with the general notion of squirrels being a conservative group. This fact does not preclude functional explanations for mandible shape, but rather indicates that ancient adaptations kept a prominent role, with most genera having diverged little from their ancestral clade morphologies. Nevertheless, certain groups have evolved conspicuous adaptations that allow them to specialize on unique dietary resources. Such adaptations mostly occurred in the Callosciurinae and probably reflect their radiation into the numerous ecological niches of the tropical and subtropical forests of Southeastern Asia. Our dietary reconstruction for the oldest known fossil squirrels (Eocene, 36 million years ago show a specialization on nuts and seeds, implying that the development from protrogomorphous to sciuromorphous skulls was not necessarily related to a change in diet.

WARMING UP FOR SLEEP - GROUND-SQUIRRELS SLEEP DURING AROUSALS FROM HIBERNATION

NARCIS (Netherlands)

DAAN, S; BARNES, BM; STRIJKSTRA, AM

1991-01-01

Hypothermia during mammalian hibernation is periodically interrupted by arousals to euthermy, the function of which is unknown. We report that arctic ground squirrels (Spermophilus parryii) consistently sleep during these arousals, and that their EEG shows the decrease in slow wave activity

An examination of endoparasites and fecal testosterone levels in flying squirrels (Glaucomys spp.) using high performance liquid chromatography-ultra-violet (HPLC-UV).

Science.gov (United States)

Waksmonski, Sarah N; Huffman, Justin M; Mahan, Carolyn G; Steele, Michael A

2017-08-01

The immuno-competence hypothesis proposes that higher levels of testosterone increases the susceptibility to parasitism. Here we examined the testosterone levels in two species of flying squirrels ( Glaucomys ): one known to regularly host a nematode species ( Strongyloides robustus ) without ill effects ( G. volans ) and a closely related species that is considered negatively affected by the parasite. We quantified fecal testosterone levels in northern and southern flying squirrels ( G. sabrinus, G. volans ) with high-performance liquid chromatography-ultraviolet spectroscopy (HPLC-UV), and compared levels to endoparasites detected in individual squirrels. Qualitatively, we found highest levels of testosterone in male northern flying squirrels infected with Strongyloides robustus . This analytical approach represents an alternative and equally reliable method to using enzyme-linked immunosorbent assay (ELISA), for detecting and quantifying fecal testosterone levels.

An examination of endoparasites and fecal testosterone levels in flying squirrels (Glaucomys spp. using high performance liquid chromatography-ultra-violet (HPLC-UV

Directory of Open Access Journals (Sweden)

Sarah N. Waksmonski

2017-08-01

Full Text Available The immuno-competence hypothesis proposes that higher levels of testosterone increases the susceptibility to parasitism. Here we examined the testosterone levels in two species of flying squirrels (Glaucomys: one known to regularly host a nematode species (Strongyloides robustus without ill effects (G. volans and a closely related species that is considered negatively affected by the parasite. We quantified fecal testosterone levels in northern and southern flying squirrels (G. sabrinus, G. volans with high-performance liquid chromatography-ultraviolet spectroscopy (HPLC-UV, and compared levels to endoparasites detected in individual squirrels. Qualitatively, we found highest levels of testosterone in male northern flying squirrels infected with Strongyloides robustus. This analytical approach represents an alternative and equally reliable method to using enzyme-linked immunosorbent assay (ELISA, for detecting and quantifying fecal testosterone levels.

Red squirrels from south–east Iberia: low genetic diversity at the southernmost species distribution limit

Directory of Open Access Journals (Sweden)

Lucas, J. M.

2015-05-01

Full Text Available South–east Iberia is the southernmost limit of this species in Europe. Squirrels in the region mainly inhabit coniferous forests of Pinus. In this study, we analyzed the pattern of mitochondrial genetic variation of southern Iberian red squirrels. Fragments of two mitochondrial genes, a 350–base pair of the displacement loop (D–loop and a 359–bp of the cytochrome b (Cytb, were sequenced using samples collected from 88 road–kill squirrels. The genetic variation was low, possibly explained by a recent bottleneck due to historical over–exploitation of forest resources. Habitat loss and fragmentation caused by deforestation and geographic isolation may explain the strong genetic subdivision between the study regions. Six new haplotypes for the D–loop and two new haplotypes for the Cytb fragments are described. A Cytb haplotype of south–east Iberia was found to be present in Albania and Japan, suggesting local extinction of this haplotype in intermediate areas. No significant clustering was found for the south–east of Spain or for the other European populations (except Calabria in the phylogenetic analysis.

Dynamics of regional distribution and ecology investigation of rare mammals of taiga Eurasia (case study of flying squirrel Pteromys volans, Rodentia, Pteromyidae

Directory of Open Access Journals (Sweden)

Juri P. Kurhinen

2016-10-01

Full Text Available This study of the spatial distribution and ecology of the flying squirrel during the turn of the 20th century provides a description of new methods and techniques for detecting and accounting flying squirrels in the forest zone of Eurasia. The flying squirrel population area covers the territory of 61 regions of Russia, including Kamchatsky Krai and Chukotka Autonomous District. The number of flying squirrels in Karelia especially to the east – in the Arkhangelsk region and Western Siberia – significantly exceeds that of Finland, but considerable spatial variability in the number is obvious through all the regions: there are areas where this animal is quite abundant, or inhabits all the territory rather evenly, and there are areas where it is completely absent in vast territories even with seemingly favourable conditions. The flying squirrel is quite difficult to study and the reasons of its absence in obviously favourable areas are still to be explained. Some reasons are: the specificity of favourable landscape, forest coverage pattern, trophic relationships with predators and genetic aspect. A number of hypotheses are supposed to be tested in the nearest future.

List of the specimens of Squirrels in the Leyden Museum

NARCIS (Netherlands)

Jentink, F.A.

1883-01-01

The profound and extensive studies upon the American Squirrels by Allen 1) and Alston 2), have made this group, we must confess it, one of the best known among the Mammals. At the same time however the named authors have shown that it is almost an impossibility to give a good and exact diagnosis of

Potential for nest site competition between native and exotic tree squirrels

Science.gov (United States)

Andrew J. Edelman; John L. Koprowski; Sadie R. Bertelsen

2009-01-01

In communities where strong interspecific competition between native species is lacking, exotic and native species often exhibit intense resource competition resulting in decline of native populations. We examined the potential for interspecific competition for nest sites between co-occurring native Mt. Graham red squirrels (Tamiasciurus hudsonicus grahamensis...

Native and introduced squirrels in Italy host different Cryptosporidium spp.

Czech Academy of Sciences Publication Activity Database

Prediger, Jitka; Horčičková, Michaela; Hofmannová, L.; Sak, Bohumil; Ferrari, N.; Mazzamuto, M.V.; Romeo, C.; Wauters, L.A.; McEvoy, J.; Kváč, Martin

2017-01-01

Roč. 61, OCT (2017), s. 64-75 ISSN 0932-4739 R&D Projects: GA ČR GA15-01090S; GA MŠk LTAUSA17165 Institutional support: RVO:60077344 Keywords : Cryptosporidium * gp60 * infection * Italy * phylogeny * tree squirrels Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine OBOR OECD: Veterinary science Impact factor: 2.581, year: 2016

Biogeography of squirrel monkeys (genus Saimiri): South-central Amazon origin and rapid pan-Amazonian diversification of a lowland primate.

Science.gov (United States)

Lynch Alfaro, Jessica W; Boubli, Jean P; Paim, Fernanda P; Ribas, Camila C; Silva, Maria Nazareth F da; Messias, Mariluce R; Röhe, Fabio; Mercês, Michelle P; Silva Júnior, José S; Silva, Claudia R; Pinho, Gabriela M; Koshkarian, Gohar; Nguyen, Mai T T; Harada, Maria L; Rabelo, Rafael M; Queiroz, Helder L; Alfaro, Michael E; Farias, Izeni P

2015-01-01

The squirrel monkey, Saimiri, is a pan-Amazonian Pleistocene radiation. We use statistical phylogeographic methods to create a mitochondrial DNA-based timetree for 118 squirrel monkey samples across 68 localities spanning all Amazonian centers of endemism, with the aim of better understanding (1) the effects of rivers as barriers to dispersal and distribution; (2) the area of origin for modern Saimiri; (3) whether ancestral Saimiri was a lowland lake-affiliated or an upland forest taxa; and (4) the effects of Pleistocene climate fluctuation on speciation. We also use our topology to help resolve current controversies in Saimiri taxonomy and species relationships. The Rondônia and Inambari centers in the southern Amazon were recovered as the most likely areas of origin for Saimiri. The Amazon River proved a strong barrier to dispersal, and squirrel monkey expansion and diversification was rapid, with all speciation events estimated to occur between 1.4 and 0.6Ma, predating the last three glacial maxima and eliminating climate extremes as the main driver of squirrel monkey speciation. Saimiri expansion was concentrated first in central and western Amazonia, which according to the "Young Amazon" hypothesis was just becoming available as floodplain habitat with the draining of the Amazon Lake. Squirrel monkeys also expanded and diversified east, both north and south of the Amazon, coincident with the formation of new rivers. This evolutionary history is most consistent with a Young Amazon Flooded Forest Taxa model, suggesting Saimiri has always maintained a lowland wetlands niche and was able to greatly expand its range with the transition from a lacustrine to a riverine system in Amazonia. Saimiri vanzolinii was recovered as the sister group to one clade of Saimiri ustus, discordant with the traditional Gothic vs. Roman morphological division of squirrel monkeys. We also found paraphyly within each of the currently recognized species: S. sciureus, S. ustus, and S

Sensorless speed detection of squirrel-cage induction machines using stator neutral point voltage harmonics

Science.gov (United States)

Petrovic, Goran; Kilic, Tomislav; Terzic, Bozo

2009-04-01

In this paper a sensorless speed detection method of induction squirrel-cage machines is presented. This method is based on frequency determination of the stator neutral point voltage primary slot harmonic, which is dependent on rotor speed. In order to prove method in steady state and dynamic conditions the simulation and experimental study was carried out. For theoretical investigation the mathematical model of squirrel cage induction machines, which takes into consideration actual geometry and windings layout, is used. Speed-related harmonics that arise from rotor slotting are analyzed using digital signal processing and DFT algorithm with Hanning window. The performance of the method is demonstrated over a wide range of load conditions.

Effects of near-UV radiation on the protein of the grey squirrel lens

International Nuclear Information System (INIS)

Zigman, S.; Paxhia, T.; Waldron, W.

1988-01-01

In vivo exposure of grey squirrels to 40W BLB illumination resulted in alterations in the state of the lens crystallins, mainly in the outer layer of the lens. HPLC revealed an increase of the void volume or crosslinked crystallins and an increase in peptides with molecular weights lower than 20,000 d. In vitro exposure of squirrel lens aqueous extracts to Woods lamp radiation (predominantly 365 nm) led to similar but more exaggerated changes as viewed by high performance liquid chromatography. When viewed by polyacrylamide gel electrophoresis (PAGE), soluble protein crosslinking was also observed. The near-UV absorbing chromophores of low molecular weight present in the lens served as photosensitizers that enhanced the protein changes. Sodium azide inhibited the changes, indicating a role for singlet oxygen in the crosslinking. (author)

Effects of near-UV radiation on the protein of the grey squirrel lens.

Science.gov (United States)

Zigman, S; Paxhia, T; Waldron, W

1988-06-01

In vivo exposure of grey squirrels to 40W BLB illumination resulted in alterations in the state of the lens crystallins, mainly in the outer layer of the lens. HPLC revealed an increase of the void volume or crosslinked crystallins and an increase in peptides with molecular weights lower than 20,000 d. In vitro exposure of squirrel lens aqueous extracts to Woods lamp radiation (predominantly 365 nm) led to similar but more exaggerated changes as viewed by high performance liquid chromatography. When viewed by polyacrylamide gel electrophoresis (PAGE), soluble protein crosslinking was also observed. The near-UV absorbing chromophores of low molecular weight present in the lens served as photosensitizers that enhanced the protein changes. Sodium azide inhibited the changes, indicating a role for singlet oxygen in the crosslinking.

Effects of near-UV radiation on the protein of the grey squirrel lens

Energy Technology Data Exchange (ETDEWEB)

Zigman, S; Paxhia, T; Waldron, W

1988-06-01

In vivo exposure of grey squirrels to 40W BLB illumination resulted in alterations in the state of the lens crystallins, mainly in the outer layer of the lens. HPLC revealed an increase of the void volume or crosslinked crystallins and an increase in peptides with molecular weights lower than 20,000 d. In vitro exposure of squirrel lens aqueous extracts to Woods lamp radiation (predominantly 365 nm) led to similar but more exaggerated changes as viewed by high performance liquid chromatography. When viewed by polyacrylamide gel electrophoresis (PAGE), soluble protein crosslinking was also observed. The near-UV absorbing chromophores of low molecular weight present in the lens served as photosensitizers that enhanced the protein changes. Sodium azide inhibited the changes, indicating a role for singlet oxygen in the crosslinking.

Novel rotating characteristics of a squirrel-cage-type HTS induction/synchronous motor

International Nuclear Information System (INIS)

Nakamura, T; Ogama, Y; Miyake, H; Nagao, K; Nishimura, T

2007-01-01

This paper describes the rotating characteristics of a high-T c superconducting induction/synchronous motor, which possesses both asynchronous and synchronous torques even though its structure is exactly the same as the squirrel-cage-type induction motor. Two kinds of Bi-2223/Ag multifilamentary tapes were utilized for the secondary windings. A commercialized motor (1.5 kW) was subjected to this study. A conventional (normal conducting) stator (three-phase, four-pole) was directly utilized, and only the squirrel-cage windings were replaced with the superconducting tapes. The tests were performed after the fabricated motor was immersed in liquid nitrogen. The operating temperature was also varied by pumping out the liquid nitrogen. It is shown that the motor is successfully synchronized for the temperature range from 65 to 77 K. Detailed discussions for such novel rotating characteristics are reported based on the electrical equivalent circuit

Theoretical analysis of a YBCO squirrel-cage type induction motor based on an equivalent circuit

International Nuclear Information System (INIS)

Morita, G; Nakamura, T; Muta, I

2006-01-01

A HTS induction motor, with a HTS squirrel-cage rotor, is analysed using an electrical equivalent circuit. The squirrel-cage winding in the rotor consists of rotor bars and end rings, and both are considered to be made of YBCO film conductors. A wide range of electric field versus current density in YBCO film is formulated based on the Weibull function, and analysed as a non-linear resistance in the equivalent circuit. It is shown that starting and accelerating torques of the HTS induction motor are improved drastically compared to those of a conventional induction motor. Furthermore, large synchronous torque can also be realized by trapping the magnetic flux in the rotor circuit because of the persistent current mode

Effect of Environmental Enrichment on Singly- and Group-Housed Squirrel Monkeys

Science.gov (United States)

Spring, Sarah E.; Clifford, James O.; Tomko, David L.; Hargens, Alan R. (Technical Monitor)

1996-01-01

Nonhuman primates display an interest in novel places, habituate to new situations, and spend most of their daily activity in the wild in large groups engaging in feeding behaviors. Captivity changes these behaviors, and disrupts normal social hierarchies. In captivity, animals may exhibit stereotypical behaviors which are thought to indicate decreased psychological well-being (PWB). If an animal's behaviors can be made to approach those seen in the wild, and stereotypical behaviors are minimal it is assumed that PWB is adequate. Environmental enrichment (EE) devices have been used to address the Animal Welfare Act's requirement that the PWB of captive nonhuman primates be considered. The purpose of the present study was to examine whether various EE devices improve the PWB of captive squirrel monkeys. The present study used behavioral observation to quantify the effectiveness of several EE devices in reducing stereotypical behaviors in squirrel monkeys housed singly or in groups. Results showed that the EE devices used did not affect the expression of normal or stereotypical behaviors, but that the type of housing did.

Suspension of Mitotic Activity in Dentate Gyrus of the Hibernating Ground Squirrel

Directory of Open Access Journals (Sweden)

Victor I. Popov

2011-01-01

Full Text Available Neurogenesis occurs in the adult mammalian hippocampus, a region of the brain important for learning and memory. Hibernation in Siberian ground squirrels provides a natural model to study mitosis as the rapid fall in body temperature in 24 h (from 35-36°C to +4–6°C permits accumulation of mitotic cells at different stages of the cell cycle. Histological methods used to study adult neurogenesis are limited largely to fixed tissue, and the mitotic state elucidated depends on the specific phase of mitosis at the time of day. However, using an immunohistochemical study of doublecortin (DCX and BrdU-labelled neurons, we demonstrate that the dentate gyrus of the ground squirrel hippocampus contains a population of immature cells which appear to possess mitotic activity. Our data suggest that doublecortin-labelled immature cells exist in a mitotic state and may represent a renewable pool for generation of new neurons within the dentate gyrus.

Parameters of mating effort and success in male European ground squirrels, Spermophilus citellus

NARCIS (Netherlands)

Millesi, E; Dittami, J; Hoffmann, [No Value; Daan, S; Hoffmann, Ilse; Wickler, W.

Behavioural and physiological changes during the reproductive period were documented in male European ground squirrels including: initiated conflict, scent marking, locomotion and range size, as well as testis size, scrotal pigmentation, testosterone levels and changes in body mass. Spring emergence

Presence of Rhodnius ecuadoriensis in sylvatic habitats in the southern highlands (Loja Province) of Ecuador.

Science.gov (United States)

Grijalva, M J; Villacis, A G

2009-05-01

The main vectors of Chagas disease in Ecuador are Triatoma dimidiata and Rhodnius ecuadoriensis. The latter species occupies domestic and peridomestic habitats, as well as sylvatic ecotopes--particularly associated with Phytelephas aequatorialis palm trees--in the western coastal region of Ecuador. In the southern highlands, however, such palm tree habitats are uncommon, and sylvatic populations of R. ecuadoriensis have not previously been reported to date. This study was carried out in five rural communities in Loja Province in southern Ecuador, where manual triatomine searches were conducted in various sylvatic habitats. A total of 81 squirrel nests (Sciurus stramineus) and > 200 bird nests and other habitats were searched. One hundred three R. ecuadoriensis individuals were found in 11 squirrel nests (infestation index = 13.6%, density = 2 bugs per nest searched, crowding = 9.5 bugs per infested nest, colonization index = 72.7% of infested nests with nymphs). No triatomines were found in bird nests or other sylvatic habitats. The presence of sylvatic R. ecuadoriensis in the southern highlands of Ecuador has important implications for the long-term control of Chagas disease in the region because of the possibility of reinfestation of dwellings after insecticide-based control interventions.

COMBINATIONS OF SQUIRRELS-POLISAHARID IN WORKING OUT OF QUALITATIVE MEAT PRODUCTS

Directory of Open Access Journals (Sweden)

L. V. Antipova

2012-01-01

Full Text Available The new multifunctional additive created in kombina-tsii of squirrels-polisaharid is developed. Results of morphological researches and technological schemes of manufacture meat produk with application of a multifunctional additive, and also a chemical compound and органолептические and physical and chemical indicators polufab-rikatov are presented.

Northern flying squirrel mycophagy and truffle production in fir forests in northeastern California

Science.gov (United States)

J.R. Waters; K.S. McKelvey; C.J. Zabel; D.L. Luoma

2000-01-01

In this paper we summarize the results of four studies in which we either examined the feeding habits of the northern flying squirrel (Glaucomys sabrinus), a mycophagous (consuming fungi) small mammal, or compared the abundance of truffles (sporocarps of hypogeous mycorrhizal fungi) among different types of fir (Abies) forest....

Dissecting the mechanisms of squirrel monkey (Saimiri boliviensis) social learning.

Science.gov (United States)

Hopper, Lm; Holmes, An; Williams, LE; Brosnan, Sf

2013-01-01

Although the social learning abilities of monkeys have been well documented, this research has only focused on a few species. Furthermore, of those that also incorporated dissections of social learning mechanisms, the majority studied either capuchins (Cebus apella) or marmosets (Callithrix jacchus). To gain a broader understanding of how monkeys gain new skills, we tested squirrel monkeys (Saimiri boliviensis) which have never been studied in tests of social learning mechanisms. To determine whether S. boliviensis can socially learn, we ran "open diffusion" tests with monkeys housed in two social groups (N = 23). Over the course of 10 20-min sessions, the monkeys in each group observed a trained group member retrieving a mealworm from a bidirectional task (the "Slide-box"). Two thirds (67%) of these monkeys both learned how to operate the Slide-box and they also moved the door significantly more times in the direction modeled by the trained demonstrator than the alternative direction. To tease apart the underlying social learning mechanisms we ran a series of three control conditions with 35 squirrel monkeys that had no previous experience with the Slide-box. The first replicated the experimental open diffusion sessions but without the inclusion of a trained model, the second was a no-information control with dyads of monkeys, and the third was a 'ghost' display shown to individual monkeys. The first two controls tested for the importance of social support (mere presence effect) and the ghost display showed the affordances of the task to the monkeys. The monkeys showed a certain level of success in the group control (54% of subjects solved the task on one or more occasions) and paired controls (28% were successful) but none were successful in the ghost control. We propose that the squirrel monkeys' learning, observed in the experimental open diffusion tests, can be best described by a combination of social learning mechanisms in concert; in this case, those

Reproduction, embryonic development, and maternal transfer of contaminants in the amphibian Gastrophryne carolinensis

Energy Technology Data Exchange (ETDEWEB)

Hopkins, W.A.; DuRant, S.E.; Staub, B.P.; Rowe, C.L.; Jackson, B.P. [Virginia Polytechnic Institute & State University, Blacksburg, VA (United States). Dept. of Fisheries & Wildlife Science

2006-05-15

Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial area transferred significant quantities of selenium and strontium to their eggs, but Se concentrations were most notable (up to 100 {mu} g/g dry mass). Compared with the reference site, hatching success was reduced by 11% in clutches from the contaminated site. In surviving larvae, the frequency of developmental abnormalities and abnormal swimming was 55-58% higher in the contaminated site relative to the reference site. Craniofacial abnormalities were nearly an order of magnitude more prevalent in hatchlings from the contaminated site. When all developmental criteria were considered collectively, offspring from the contaminated site experienced 19% lower viability. Although there was no statistical relationship between the concentration of Se or Sr transferred to eggs and any measure of offspring viability, our study demonstrates that maternal transfer may be an important route of contaminant exposure in amphibians that has been overlooked.

Dynamic modeling of an asynchronous squirrel-cage machine; Modelisation dynamique d'une machine asynchrone a cage

Energy Technology Data Exchange (ETDEWEB)

Guerette, D.

2009-07-01

This document presented a detailed mathematical explanation and validation of the steps leading to the development of an asynchronous squirrel-cage machine. The MatLab/Simulink software was used to model a wind turbine at variable high speeds. The asynchronous squirrel-cage machine is an electromechanical system coupled to a magnetic circuit. The resulting electromagnetic circuit can be represented as a set of resistances, leakage inductances and mutual inductances. Different models were used for a comparison study, including the Munteanu, Boldea, Wind Turbine Blockset, and SimPowerSystem. MatLab/Simulink modeling results were in good agreement with the results from other comparable models. Simulation results were in good agreement with analytical calculations. 6 refs, 2 tabs, 9 figs.

An examination of endoparasites and fecal testosterone levels in flying squirrels (Glaucomys spp.) using high performance liquid chromatography-ultra-violet (HPLC-UV)

OpenAIRE

Waksmonski, Sarah N.; Huffman, Justin M.; Mahan, Carolyn G.; Steele, Michael A.

2017-01-01

The immuno-competence hypothesis proposes that higher levels of testosterone increases the susceptibility to parasitism. Here we examined the testosterone levels in two species of flying squirrels (Glaucomys): one known to regularly host a nematode species (Strongyloides robustus) without ill effects (G. volans) and a closely related species that is considered negatively affected by the parasite. We quantified fecal testosterone levels in northern and southern flying squirrels (G. sabrinus, G...

Differential estimates of southern flying squirrel (Glaucomys volans) population structure based on capture method

Science.gov (United States)

Kevin S. Laves; Susan C. Loeb

2005-01-01

It is commonly assumed that population estimates derived from trapping small mammals are accurate and unbiased or that estimates derived from different capture methods are comparable. We captured southern flying squirrels (Glaucmrtys volam) using two methods to study their effect on red-cockaded woodpecker (Picoides bumah) reproductive success. Southern flying...

Microsatellite Analysis of the Population Genetic Structure of Anolis carolinensis Introduced to the Ogasawara Islands.

Science.gov (United States)

Sugawara, Hirotaka; Takahashi, Hiroo; Hayashi, Fumio

2015-01-01

DNA analysis can reveal the origins and dispersal patterns of invasive species. The green anole Anolis carolinensis is one such alien animal, which has been dispersed widely by humans from its native North America to many Pacific Ocean islands. In the Ogasawara (Bonin) Islands, this anole was recorded from Chichi-jima at the end of the 1960s, and then from Haha-jima in the early 1980s. These two islands are inhabited. In 2013, it was also found on the uninhabited Ani-jima, close to Chichi-jima. Humans are thought to have introduced the anole to Haha-jima, while the mode of introduction to Ani-jima is unknown. To clarify its dispersal patterns within and among these three islands, we assessed the fine-scale population genetic structure using five microsatellite loci. The results show a homogeneous genetic structure within islands, but different genetic structures among islands, suggesting that limited gene flow occurs between islands. The recently established Ani-jima population may have originated from several individuals simultaneously, or by repeated immigration from Chichi-jima. We must consider frequent incursions among these islands to control these invasive lizard populations and prevent their negative impact on native biodiversity.

Lethal and sublethal measures of chronic copper toxicity in the eastern narrowmouth toad, Gastrophryne carolinensis.

Science.gov (United States)

Flynn, R Wesley; Scott, David E; Kuhne, Wendy; Soteropoulos, Diana; Lance, Stacey L

2015-03-01

Many metals are acutely toxic to aquatic organisms at high concentrations and for some metals, such as copper (Cu), even low-level chronic contamination may be cause for conservation concern. Amphibian susceptibility to Cu has been examined in only a few species, and susceptibility is highly variable. The lethal and sublethal effects were examined of chronic aqueous Cu exposure on embryonic and larval eastern narrowmouth toads, Gastrophryne carolinensis. Copper levels as low as 10 μg Cu/L reduced embryonic and larval survival. Embryonic survivorship varied within- and between-source populations, with embryos derived from uncontaminated-wetland parents having greater survival at lower Cu levels than embryos from parents from a metal-contaminated constructed wetland. At 30 μg/L, embryos from the contaminated site had greater survival. Overall survival from oviposition to metamorphosis was 68.9% at 0 μg/L and 5.4% at 10 μg/L. Similarly, embryos exposed to ≥50 μg/L demonstrated developmental delays in transition from embryo to free-swimming larva. These results demonstrate a negative population-specific response to environmentally relevant levels of Cu. © 2014 SETAC.

Permanent Genetic Resources added to Molecular Ecology Resources database 1 January 2009-30 April 2009.

Science.gov (United States)

Abercrombie, L G; Anderson, C M; Baldwin, B G; Bang, I C; Beldade, R; Bernardi, G; Boubou, A; Branca, A; Bretagnolle, F; Bruford, M W; Buonamici, A; Burnett, R K; Canal, D; Cárdenas, H; Caullet, C; Chen, S Y; Chun, Y J; Cossu, C; Crane, C F; Cros-Arteil, S; Cudney-Bueno, R; Danti, R; Dávila, J A; Della Rocca, G; Dobata, S; Dunkle, L D; Dupas, S; Faure, N; Ferrero, M E; Fumanal, B; Gigot, G; González, I; Goodwin, S B; Groth, D; Hardesty, B D; Hasegawa, E; Hoffman, E A; Hou, M L; Jamsari, A F J; Ji, H J; Johnson, D H; Joseph, L; Justy, F; Kang, E J; Kaufmann, B; Kim, K S; Kim, W J; Koehler, A V; Laitung, B; Latch, P; Liu, Y D; Manjerovic, M B; Martel, E; Metcalfe, S S; Miller, J N; Midgley, J J; Migeon, A; Moore, A J; Moore, W L; Morris, V R F; Navajas, M; Navia, D; Neel, M C; De Nova, P J G; Olivieri, I; Omura, T; Othman, A S; Oudot-Canaff, J; Panthee, D R; Parkinson, C L; Patimah, I; Pérez-Galindo, C A; Pettengill, J B; Pfautsch, S; Piola, F; Potti, J; Poulin, R; Raimondi, P T; Rinehart, T A; Ruzainah, A; Sarver, S K; Scheffler, B E; Schneider, A R R; Silvain, J F; Siti Azizah, M N; Springer, Y P; Stewart, C N; Sun, W; Tiedemann, R; Tsuji, K; Trigiano, R N; Vendramin, G G; Wadl, P A; Wang, L; Wang, X; Watanabe, K; Waterman, J M; Weisser, W W; Westcott, D A; Wiesner, K R; Xu, X F; Yaegashi, S; Yuan, J S

2009-09-01

This article documents the addition of 283 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Agalinis acuta; Ambrosia artemisiifolia; Berula erecta; Casuarius casuarius; Cercospora zeae-maydis; Chorthippus parallelus; Conyza canadensis; Cotesia sesamiae; Epinephelus acanthistius; Ficedula hypoleuca; Grindelia hirsutula; Guadua angustifolia; Leucadendron rubrum; Maritrema novaezealandensis; Meretrix meretrix; Nilaparvata lugens; Oxyeleotris marmoratus; Phoxinus neogaeus; Pristomyrmex punctatus; Pseudobagrus brevicorpus; Seiridium cardinale; Stenopsyche marmorata; Tetranychus evansi and Xerus inauris. These loci were cross-tested on the following species: Agalinis decemloba; Agalinis tenella; Agalinis obtusifolia; Agalinis setacea; Agalinis skinneriana; Cercospora zeina; Cercospora kikuchii; Cercospora sorghi; Mycosphaerella graminicola; Setosphaeria turcica; Magnaporthe oryzae; Cotesia flavipes; Cotesia marginiventris; Grindelia Xpaludosa; Grindelia chiloensis; Grindelia fastigiata; Grindelia lanceolata; Grindelia squarrosa; Leucadendron coniferum; Leucadendron salicifolium; Leucadendron tinctum; Leucadendron meridianum; Laodelphax striatellus; Sogatella furcifera; Phoxinus eos; Phoxinus rigidus; Phoxinus brevispinosus; Phoxinus bicolor; Tetranychus urticae; Tetranychus turkestani; Tetranychus ludeni; Tetranychus neocaledonicus; Tetranychus amicus; Amphitetranychus viennensis; Eotetranychus rubiphilus; Eotetranychus tiliarium; Oligonychus perseae; Panonychus citri; Bryobia rubrioculus; Schizonobia bundi; Petrobia harti; Xerus princeps; Spermophilus tridecemlineatus and Sciurus carolinensis. © 2009 Blackwell Publishing Ltd.

Ecological correlates of flying squirrel microhabitat use and density in temperate rainforests of southeastern Alaska

Science.gov (United States)

Winston P. Smith; Scott M. Gende; Jeffrey V. Nichols

2004-01-01

We studied habitat relations of the Prince of Wales flying squirrel (Glaucomys sabrinus griseifrons), an endemic of the temperate, coniferous rainforest of southeastern Alaska, because of concerns over population viability from extensive clear-cut logging in the region. We used stepwise logistic regression to examine relationships between...

Advanced Model of Squirrel Cage Induction Machine for Broken Rotor Bars Fault Using Multi Indicators

Directory of Open Access Journals (Sweden)

Ilias Ouachtouk

2016-01-01

Full Text Available Squirrel cage induction machine are the most commonly used electrical drives, but like any other machine, they are vulnerable to faults. Among the widespread failures of the induction machine there are rotor faults. This paper focuses on the detection of broken rotor bars fault using multi-indicator. However, diagnostics of asynchronous machine rotor faults can be accomplished by analysing the anomalies of machine local variable such as torque, magnetic flux, stator current and neutral voltage signature analysis. The aim of this research is to summarize the existing models and to develop new models of squirrel cage induction motors with consideration of the neutral voltage and to study the effect of broken rotor bars on the different electrical quantities such as the park currents, torque, stator currents and neutral voltage. The performance of the model was assessed by comparing the simulation and experimental results. The obtained results show the effectiveness of the model, and allow detection and diagnosis of these defects.

Natural entrainment without dawn and dusk : The case of the European ground squirrel (Spermophilus citellus)

NARCIS (Netherlands)

Hut, RA; van Oort, BEH; Daan, S; Oort, Bob E.H. van

Observational data collected in the field and in enclosures show that diurnal, burrow-dwelling European ground squirrels (Spermophilus citellus) never were above ground during twilight at dawn or at dusk. The animals emerged on average 4.02 h (SD = 0.45) after civil twilight at dawn and retreated in

Integrating histology and MRI in the first digital brain of common squirrel monkey, Saimiri sciureus

Science.gov (United States)

Sun, Peizhen; Parvathaneni, Prasanna; Schilling, Kurt G.; Gao, Yurui; Janve, Vaibhav; Anderson, Adam; Landman, Bennett A.

2015-03-01

This effort is a continuation of development of a digital brain atlas of the common squirrel monkey, Saimiri sciureus, a New World monkey with functional and microstructural organization of central nervous system similar to that of humans. Here, we present the integration of histology with multi-modal magnetic resonance imaging (MRI) atlas constructed from the brain of an adult female squirrel monkey. The central concept of this work is to use block face photography to establish an intermediate common space in coordinate system which preserves the high resolution in-plane resolution of histology while enabling 3-D correspondence with MRI. In vivo MRI acquisitions include high resolution T2 structural imaging (300 μm isotropic) and low resolution diffusion tensor imaging (600 um isotropic). Ex vivo MRI acquisitions include high resolution T2 structural imaging and high resolution diffusion tensor imaging (both 300 μm isotropic). Cortical regions were manually annotated on the co-registered volumes based on published histological sections in-plane. We describe mapping of histology and MRI based data of the common squirrel monkey and construction of a viewing tool that enable online viewing of these datasets. The previously descried atlas MRI is used for its deformation to provide accurate conformation to the MRI, thus adding information at the histological level to the MRI volume. This paper presents the mapping of single 2D image slice in block face as a proof of concept and this can be extended to map the atlas space in 3D coordinate system as part of the future work and can be loaded to an XNAT system for further use.

Reproduction, embryonic development, and maternal transfer of contaminants in the amphibian Gastrophryne carolinensis.

Science.gov (United States)

Hopkins, William Alexander; DuRant, Sarah Elizabeth; Staub, Brandon Patrick; Rowe, Christopher Lee; Jackson, Brian Phillip

2006-05-01

Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. Despite the severe effects of maternal transfer of contaminants on early development in other vertebrate lineages, no studies have examined the effects of maternal transfer of contaminants on reproduction or development in amphibians. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial area transferred significant quantities of selenium and strontium to their eggs, but Se concentrations were most notable (up to 100 microg/g dry mass). Compared with the reference site, hatching success was reduced by 11% in clutches from the contaminated site. In surviving larvae, the frequency of developmental abnormalities and abnormal swimming was 55-58% higher in the contaminated site relative to the reference site. Craniofacial abnormalities were nearly an order of magnitude more prevalent in hatchlings from the contaminated site. When all developmental criteria were considered collectively, offspring from the contaminated site experienced 19% lower viability. Although there was no statistical relationship between the concentration of Se or Sr transferred to eggs and any measure of offspring viability, our study demonstrates that maternal transfer may be an important route of contaminant exposure in amphibians that has been overlooked.

A census of mammal populations in Punta Leona Private Wildlife Refuge, Costa Rica

Directory of Open Access Journals (Sweden)

Joshua Timock

2002-12-01

Full Text Available Population sizes of six mammal species were estimated using the King method during the late dry season (March of 1996 in the Punta Leona Private Wildlife Refuge, Costa Rica. The white-faced monkey (Cebus capucinus, coati (Nasua narica and nine-banded armadillo (Dasypus novemcinctus with 148, 46, and 8 sighted individuals, respectively, demonstrated the largest populations in the refuge. The Central American spider monkey (Ateles geoffroyi, tamandua anteater (Tamandua mexicana, and variegated squirrel (Sciurus variegatoides were also included in the census. Population densities are calculated, habitat types are describes, and habitat use and activity periods are discussed.Se estimó el tamaño poblacional de seis especies de mamíferos, usando el método de King, durante la estación seca tardía (marzo de 1996 en el Refugio de Vida Silvestre de Punta Leona, Costa Rica. El mono carablanca (Cebus capucinus, el pizote (Nasua narica y el armadillo de 9 bandas (Dasypus novecinctus presentaron las poblaciones más grandes en el refugio, con 148, 46, y 8 observaciones respectivamente. El mono araña centroamericano (Ateles geoffroyi, el tamandúa hormiguero (Tamandua mexicana y la ardilla (Sciurus variegatoides también se tomaron en cuenta durante el censo. Además se calculan las densidades poblacionales, se describen los tipos de hábitat y se discute el uso de estos, así como los periodos de actividad de las especies encontradas.

The use of GIS and modelling approaches in squirrel population management and conservation: A review

Science.gov (United States)

P. W. W. Lurz; J. L. Koprowski; D. J. A. Wood

2008-01-01

We review modelling approaches in relation to three key areas of sciurid ecology: management, disease risk assessments and conservation. Models enable us to explore different scenarios to develop effective management and conservation strategies. They may also assist in identifying and targeting research needs for tree and flying squirrels. However, there is a need to...

Effects of GABA[subscript A] Modulators on the Repeated Acquisition of Response Sequences in Squirrel Monkeys

Science.gov (United States)

Campbell, Una C.; Winsauer, Peter J.; Stevenson, Michael W.; Moerschbaecher, Joseph M.

2004-01-01

The present study investigated the effects of positive and negative GABA[subscript A] modulators under three different baselines of repeated acquisition in squirrel monkeys in which the monkeys acquired a three-response sequence on three keys under a second-order fixed-ratio (FR) schedule of food reinforcement. In two of these baselines, the…

The northern flying squirrel as an indicator species of temperate rain forest: test of an hypothesis.

Science.gov (United States)

Winston P. Smith; Scott M. Gende; Jeffrey V. Nichols

2005-01-01

Management indicator species (MIS) often are selected because their life history and demographics are thought to reflect a suite of ecosystem conditions that are too difficult or costly to measure directly. The northern flying squirrel (Glaucomys sabrinus) has been proposed as an MIS of temperate rain forest of southeastern Alaska based on previous...

Stochastic population dynamics of a montane ground-dwelling squirrel.

Science.gov (United States)

Hostetler, Jeffrey A; Kneip, Eva; Van Vuren, Dirk H; Oli, Madan K

2012-01-01

Understanding the causes and consequences of population fluctuations is a central goal of ecology. We used demographic data from a long-term (1990-2008) study and matrix population models to investigate factors and processes influencing the dynamics and persistence of a golden-mantled ground squirrel (Callospermophilus lateralis) population, inhabiting a dynamic subalpine habitat in Colorado, USA. The overall deterministic population growth rate λ was 0.94±SE 0.05 but it varied widely over time, ranging from 0.45±0.09 in 2006 to 1.50±0.12 in 2003, and was below replacement (λbounce back from low densities and prevented extinction. These results suggest that dynamics and persistence of our study population are determined synergistically by density-dependence, stochastic forces, and immigration.

Cytoskeletal Regulation Dominates Temperature-Sensitive Proteomic Changes of Hibernation in Forebrain of 13-Lined Ground Squirrels

Science.gov (United States)

Hindle, Allyson G.; Martin, Sandra L.

2013-01-01

13-lined ground squirrels, Ictidomys tridecemlineatus, are obligate hibernators that transition annually between summer homeothermy and winter heterothermy – wherein they exploit episodic torpor bouts. Despite cerebral ischemia during torpor and rapid reperfusion during arousal, hibernator brains resist damage and the animals emerge neurologically intact each spring. We hypothesized that protein changes in the brain underlie winter neuroprotection. To identify candidate proteins, we applied a sensitive 2D gel electrophoresis method to quantify protein differences among forebrain extracts prepared from ground squirrels in two summer, four winter and fall transition states. Proteins that differed among groups were identified using LC-MS/MS. Only 84 protein spots varied significantly among the defined states of hibernation. Protein changes in the forebrain proteome fell largely into two reciprocal patterns with a strong body temperature dependence. The importance of body temperature was tested in animals from the fall; these fall animals use torpor sporadically with body temperatures mirroring ambient temperatures between 4 and 21°C as they navigate the transition between summer homeothermy and winter heterothermy. Unlike cold-torpid fall ground squirrels, warm-torpid individuals strongly resembled the homeotherms, indicating that the changes observed in torpid hibernators are defined by body temperature, not torpor per se. Metabolic enzymes were largely unchanged despite varied metabolic activity across annual and torpor-arousal cycles. Instead, the majority of the observed changes were cytoskeletal proteins and their regulators. While cytoskeletal structural proteins tended to differ seasonally, i.e., between summer homeothermy and winter heterothermy, their regulatory proteins were more strongly affected by body temperature. Changes in the abundance of various isoforms of the microtubule assembly and disassembly regulatory proteins dihydropyrimidinase

Cytoskeletal regulation dominates temperature-sensitive proteomic changes of hibernation in forebrain of 13-lined ground squirrels.

Directory of Open Access Journals (Sweden)

Allyson G Hindle

Full Text Available 13-lined ground squirrels, Ictidomys tridecemlineatus, are obligate hibernators that transition annually between summer homeothermy and winter heterothermy - wherein they exploit episodic torpor bouts. Despite cerebral ischemia during torpor and rapid reperfusion during arousal, hibernator brains resist damage and the animals emerge neurologically intact each spring. We hypothesized that protein changes in the brain underlie winter neuroprotection. To identify candidate proteins, we applied a sensitive 2D gel electrophoresis method to quantify protein differences among forebrain extracts prepared from ground squirrels in two summer, four winter and fall transition states. Proteins that differed among groups were identified using LC-MS/MS. Only 84 protein spots varied significantly among the defined states of hibernation. Protein changes in the forebrain proteome fell largely into two reciprocal patterns with a strong body temperature dependence. The importance of body temperature was tested in animals from the fall; these fall animals use torpor sporadically with body temperatures mirroring ambient temperatures between 4 and 21°C as they navigate the transition between summer homeothermy and winter heterothermy. Unlike cold-torpid fall ground squirrels, warm-torpid individuals strongly resembled the homeotherms, indicating that the changes observed in torpid hibernators are defined by body temperature, not torpor per se. Metabolic enzymes were largely unchanged despite varied metabolic activity across annual and torpor-arousal cycles. Instead, the majority of the observed changes were cytoskeletal proteins and their regulators. While cytoskeletal structural proteins tended to differ seasonally, i.e., between summer homeothermy and winter heterothermy, their regulatory proteins were more strongly affected by body temperature. Changes in the abundance of various isoforms of the microtubule assembly and disassembly regulatory proteins

Up-regulation of Long Non-coding RNA TUG1 in Hibernating Thirteen-lined Ground Squirrels

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Jacques J. Frigault

2016-04-01

Full Text Available Mammalian hibernation is associated with multiple physiological, biochemical, and molecular changes that allow animals to endure colder temperatures. We hypothesize that long non-coding RNAs (lncRNAs, a group of non-coding transcripts with diverse functions, are differentially expressed during hibernation. In this study, expression levels of lncRNAs H19 and TUG1 were assessed via qRT-PCR in liver, heart, and skeletal muscle tissues of the hibernating thirteen-lined ground squirrels (Ictidomys tridecemlineatus. TUG1 transcript levels were significantly elevated 1.94-fold in skeletal muscle of hibernating animals when compared with euthermic animals. Furthermore, transcript levels of HSF2 also increased 2.44-fold in the skeletal muscle in hibernating animals. HSF2 encodes a transcription factor that can be negatively regulated by TUG1 levels and that influences heat shock protein expression. Thus, these observations support the differential expression of the TUG1–HSF2 axis during hibernation. To our knowledge, this study provides the first evidence for differential expression of lncRNAs in torpid ground squirrels, adding lncRNAs as another group of transcripts modulated in this mammalian species during hibernation.

Foraging density for squirrel monkey Saimiri sciureus in two forests in Puerto Lopez - Colombia

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Jorge Astwood R.

2014-06-01

Full Text Available Objective. Forest remnants were analyzed to determine the density of squirrel monkeys (Saimiri sciureus and the degree of alteration of the forest, by selecting areas for the conservation and maintenance of the species in natural environments. Materials and methods. Linear transects were conducted on two wooden fragments, “La Reforma” and “Campo Hermoso” farms (Puerto Lopez, Meta, Colombia, recording sightings of squirrel monkeys and identifying the tree species used by the primates. Results. The fragments studied correspond to trails at the edge of water bodies with low connectivity. Highest density values were observed on the second transect of La Reforma, a possible consequence of an overcrowding phenomenon due to the high degree of isolation of the fragment. The species preferentially used as refuge and food source were: Bellucia grossularioides, Eugenia jambos, Inga alba, Mauritia flexuosa, Pseudolmedia laevis and Rollinia edulis. Conclusions. The phenology of the plant species allows for a dynamic food supply, considering the constant availability of food for the primates. Therefore, despite the evident ecological problem of these forests, it is possible to use active restoration programs to strengthen the existing dynamics and balance the biogeochemical dynamics of the ecosystem, so that socioeconomic human activities are not in conflict with conservation efforts and vice versa.

Application of novel hall sensor technique to evaluate internal defect nondestructively in squirrel cage rotor

International Nuclear Information System (INIS)

Park, Myung Ju; Lee, Joon Hyun

1998-01-01

Development of Nondestructive Tester for industrial application to detect flaws in aluminum die-casted squirrel case rotor is reported in this paper. Electronic currents are supplied to the end-ring and Hall effect sensors are used to detect the variation of currents which flow in the bar of the rotor. Some signal processing techniques are introduced to classify the signals due to the defects in the bars

Test of the prey-base hypothesis to explain use of red squirrel midden sites by American martens

Science.gov (United States)

Dean E. Pearson; Leonard F. Ruggiero

2001-01-01

We tested the prey-base hypothesis to determine whether selection of red squirrel (Tamiasciurus hudsonicus) midden sites (cone caches) by American martens (Martes americana) for resting and denning could be attributed to greater abundance of small-mammal prey. Five years of livetrapping at 180 sampling stations in 2 drainages showed that small mammals,...

Diet and food availability: implications for foraging and dispersal of Prince of Wales northern flying squirrels across managed landscapes

Science.gov (United States)

Elizabeth A. Flaherty; Merav Ben-David; Winston P. Smith

2010-01-01

Where dispersal is energetically expensive, feeding and food availability can influence dispersal success. The endemic Prince of Wales northern flying squirrel (Glaucomys sabrinus griseifrons) inhabits a landscape mosaic of old-growth, second-growth, and clearcut stands, with the latter two representing energetically expensive habitats. We...

Area occupancy and detection probabilities of the Virginia northern flying squirrel (Glaucomys sabrinus fuscus) using nest-box surveys

Science.gov (United States)

W. Mark Ford; Kurtis R. Moseley; Craig W. Stihler; John W. Edwards

2010-01-01

Concomitant with the delisting of the endangered Virginia northern flying squirrel (Glaucomys sabrinus fuscus) in 2008, the U.S. Fish and Wildlife Service mandated a 10-year post-delisting monitoring effort to ensure that subspecies population and distribution stability will persist following a changed regulatory status. Although criticized for the...

Up-regulation of Long Non-coding RNA TUG1 in Hibernating Thirteen-lined Ground Squirrels.

Science.gov (United States)

Frigault, Jacques J; Lang-Ouellette, Daneck; Morin, Pier

2016-04-01

Mammalian hibernation is associated with multiple physiological, biochemical, and molecular changes that allow animals to endure colder temperatures. We hypothesize that long non-coding RNAs (lncRNAs), a group of non-coding transcripts with diverse functions, are differentially expressed during hibernation. In this study, expression levels of lncRNAsH19 and TUG1 were assessed via qRT-PCR in liver, heart, and skeletal muscle tissues of the hibernating thirteen-lined ground squirrels (Ictidomys tridecemlineatus). TUG1 transcript levels were significantly elevated 1.94-fold in skeletal muscle of hibernating animals when compared with euthermic animals. Furthermore, transcript levels of HSF2 also increased 2.44-fold in the skeletal muscle in hibernating animals. HSF2 encodes a transcription factor that can be negatively regulated by TUG1 levels and that influences heat shock protein expression. Thus, these observations support the differential expression of the TUG1-HSF2 axis during hibernation. To our knowledge, this study provides the first evidence for differential expression of lncRNAs in torpid ground squirrels, adding lncRNAs as another group of transcripts modulated in this mammalian species during hibernation. Copyright © 2016 The Authors. Production and hosting by Elsevier Ltd.. All rights reserved.

Trait-specific processes of convergence and conservatism shape ecomorphological evolution in ground-dwelling squirrels.

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McLean, Bryan S; Helgen, Kristofer M; Goodwin, H Thomas; Cook, Joseph A

2018-03-01

Our understanding of mechanisms operating over deep timescales to shape phenotypic diversity often hinges on linking variation in one or few trait(s) to specific evolutionary processes. When distinct processes are capable of similar phenotypic signatures, however, identifying these drivers is difficult. We explored ecomorphological evolution across a radiation of ground-dwelling squirrels whose history includes convergence and constraint, two processes that can yield similar signatures of standing phenotypic diversity. Using four ecologically relevant trait datasets (body size, cranial, mandibular, and molariform tooth shape), we compared and contrasted variation, covariation, and disparity patterns in a new phylogenetic framework. Strong correlations existed between body size and two skull traits (allometry) and among skull traits themselves (integration). Inferred evolutionary modes were also concordant across traits (Ornstein-Uhlenbeck with two adaptive regimes). However, despite these broad similarities, we found divergent dynamics on the macroevolutionary landscape, with phenotypic disparity being differentially shaped by convergence and conservatism. Such among-trait heterogeneity in process (but not always pattern) reiterates the mosaic nature of morphological evolution, and suggests ground squirrel evolution is poorly captured by single process descriptors. Our results also highlight how use of single traits can bias macroevolutionary inference, affirming the importance of broader trait-bases in understanding phenotypic evolutionary dynamics. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Predictive habitat models derived from nest-box occupancy for the endangered Carolina northern flying squirrel in the southern Appalachians

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Ford, W. Mark; Evans, A.M.; Odom, Richard H.; Rodrigue, Jane L.; Kelly, C.A.; Abaid, Nicole; Diggins, Corinne A.; Newcomb, Doug

2016-01-01

In the southern Appalachians, artificial nest-boxes are used to survey for the endangered Carolina northern flying squirrel (CNFS; Glaucomys sabrinus coloratus), a disjunct subspecies associated with high elevation (>1385 m) forests. Using environmental parameters diagnostic of squirrel habitat, we created 35 a priori occupancy models in the program PRESENCE for boxes surveyed in western North Carolina, 1996-2011. Our best approximating model showed CNFS denning associated with sheltered landforms and montane conifers, primarily red spruce Picea rubens. As sheltering decreased, decreasing distance to conifers was important. Area with a high probability (>0.5) of occupancy was distributed over 18662 ha of habitat, mostly across 10 mountain ranges. Because nest-box surveys underrepresented areas >1750 m and CNFS forage in conifers, we combined areas of high occupancy with conifer GIS coverages to create an additional distribution model of likely habitat. Regionally, above 1385 m, we determined that 31795 ha could be occupied by CNFS. Known occupied patches ranged from

Removal of acorns of the alien oak Quercus rubra on the ground by scatter-hoarding animals in Belgian forests

Directory of Open Access Journals (Sweden)

Merceron, NR.

2017-01-01

Full Text Available Description of the subject. Quercus rubra L. is considered an invasive species in several European countries. However, little is known about its dispersal in the introduced range. Objectives. We investigated the significance of animal dispersal of Q. rubra acorns on the ground by vertebrates in its introduced range, and identified the animal species involved. Method. During two consecutive autumns, the removal of acorns from Q. rubra and from a native oak was assessed weekly in forest sites in Belgium. We used automated detection camera traps to identify the animals that removed acorns. Results. Quercus rubra acorns were removed by wood mice (Apodemus sylvaticus L., red squirrels (Sciurus vulgaris L., rats (Rattus sp., and wild boars (Sus scrofa L.. The two former are scatter-hoarding rodents and can be considered potential dispersers. Conclusions. Dispersal of Q. rubra acorns in Western Europe by scatter-hoarding animals may help the species increasingly colonize forest ecosystems.

Using dynamic N-mixture models to test cavity limitation on northern flying squirrel demographic parameters using experimental nest box supplementation.

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Priol, Pauline; Mazerolle, Marc J; Imbeau, Louis; Drapeau, Pierre; Trudeau, Caroline; Ramière, Jessica

2014-06-01

Dynamic N-mixture models have been recently developed to estimate demographic parameters of unmarked individuals while accounting for imperfect detection. We propose an application of the Dail and Madsen (2011: Biometrics, 67, 577-587) dynamic N-mixture model in a manipulative experiment using a before-after control-impact design (BACI). Specifically, we tested the hypothesis of cavity limitation of a cavity specialist species, the northern flying squirrel, using nest box supplementation on half of 56 trapping sites. Our main purpose was to evaluate the impact of an increase in cavity availability on flying squirrel population dynamics in deciduous stands in northwestern Québec with the dynamic N-mixture model. We compared abundance estimates from this recent approach with those from classic capture-mark-recapture models and generalized linear models. We compared apparent survival estimates with those from Cormack-Jolly-Seber (CJS) models. Average recruitment rate was 6 individuals per site after 4 years. Nevertheless, we found no effect of cavity supplementation on apparent survival and recruitment rates of flying squirrels. Contrary to our expectations, initial abundance was not affected by conifer basal area (food availability) and was negatively affected by snag basal area (cavity availability). Northern flying squirrel population dynamics are not influenced by cavity availability at our deciduous sites. Consequently, we suggest that this species should not be considered an indicator of old forest attributes in our study area, especially in view of apparent wide population fluctuations across years. Abundance estimates from N-mixture models were similar to those from capture-mark-recapture models, although the latter had greater precision. Generalized linear mixed models produced lower abundance estimates, but revealed the same relationship between abundance and snag basal area. Apparent survival estimates from N-mixture models were higher and less precise

Groundwater quality, age, and susceptibility and vulnerability to nitrate contamination with linkages to land use and groundwater flow, Upper Black Squirrel Creek Basin, Colorado, 2013

Science.gov (United States)

Wellman, Tristan P.; Rupert, Michael G.

2016-03-03

The Upper Black Squirrel Creek Basin is located about 25 kilometers east of Colorado Springs, Colorado. The primary aquifer is a productive section of unconsolidated deposits that overlies bedrock units of the Denver Basin and is a critical resource for local water needs, including irrigation, domestic, and commercial use. The primary aquifer also serves an important regional role by the export of water to nearby communities in the Colorado Springs area. Changes in land use and development over the last decade, which includes substantial growth of subdivisions in the Upper Black Squirrel Creek Basin, have led to uncertainty regarding the potential effects to water quality throughout the basin. In response, the U.S. Geological Survey, in cooperation with Cherokee Metropolitan District, El Paso County, Meridian Service Metropolitan District, Mountain View Electric Association, Upper Black Squirrel Creek Groundwater Management District, Woodmen Hills Metropolitan District, Colorado State Land Board, and Colorado Water Conservation Board, and the stakeholders represented in the Groundwater Quality Study Committee of El Paso County conducted an assessment of groundwater quality and groundwater age with an emphasis on characterizing nitrate in the groundwater.

Nectin-4 Interactions Govern Measles Virus Virulence in a New Model of Pathogenesis, the Squirrel Monkey (Saimiri sciureus).

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Delpeut, Sébastien; Sawatsky, Bevan; Wong, Xiao-Xiang; Frenzke, Marie; Cattaneo, Roberto; von Messling, Veronika

2017-06-01

In addition to humans, only certain nonhuman primates are naturally susceptible to measles virus (MeV) infection. Disease severity is species dependent, ranging from mild to moderate for macaques to severe and even lethal for certain New World monkey species. To investigate if squirrel monkeys ( Saimiri sciureus ), which are reported to develop a course of disease similar to humans, may be better suited than macaques for the identification of virulence determinants or the evaluation of therapeutics, we infected them with a green fluorescent protein-expressing MeV. Compared to cynomolgus macaques ( Macaca fascicularis ) infected with the same virus, the squirrel monkeys developed more-severe immunosuppression, higher viral load, and a broader range of clinical signs typical for measles. In contrast, infection with an MeV unable to interact with the epithelial receptor nectin-4, while causing immunosuppression, resulted in only a mild and transient rash and a short-lived elevation of the body temperature. Similar titers of the wild-type and nectin-4-blind MeV were detected in peripheral blood mononuclear cells and lymph node homogenates, but only the wild-type virus was found in tracheal lavage fluids and urine. Thus, our study demonstrates the importance of MeV interactions with nectin-4 for clinical disease in the new and better-performing S. sciureus model of measles pathogenesis. IMPORTANCE The characterization of mechanisms underlying measles virus clinical disease has been hampered by the lack of an animal model that reproduces the course of disease seen in human patients. Here, we report that infection of squirrel monkeys ( Saimiri sciureus ) fulfills these requirements. Comparative infection with wild-type and epithelial cell receptor-blind viruses demonstrated the importance of epithelial cell infection for clinical disease, highlighting the spread to epithelia as an attractive target for therapeutic strategies. Copyright © 2017 American Society for

State-dependent variation in the inhibitory effect of (D-Ala sup 2 , D-Leu sup 5 )-enkephalin on hippocampal serotonin release in ground squirrels

Energy Technology Data Exchange (ETDEWEB)

Kramarova, L.I.; Lee, T.F.; Cui, Y.; Wang, L.C.H. (Univ. of Alberta, Edmonton (Canada))

1990-01-01

Accumulated evidence has suggested that increased endogenous opioid activities may facilitate the onset of hibernation either directly or possibly through modulation of other neurotransmitter systems. The seasonal change of (D-Ala{sup 2}, D-Leu{sup 5})-enkephalin (DADLE), a {delta} receptor agonist, in modulating K{sup +}-induced ({sup 3}H)-5-hydroxytryptamine (5-HT) release from the hippocampal and hypothalamic slices of euthermic and hibernating Richardsons' ground squirrels was therefore investigated. DADLE had no effect on 5-HT release in the hypothalamic slices but elicited a dose-related inhibition on ({sup 3}H)-5-HT release from the hippocampal slices of the euthermic ground squirrel. The inhibitory effect of DADLE was completely reversed by naloxone, but not by tetrodotoxin. In contrast, DADLE failed to alter the K{sup +}-induced 5-HT release from the hippocampal slices of the hibernating ground squirrel. This state-dependent reduction in responsiveness to an opioid is consistent with the hypothesis that enhanced endogenous opioid activity in the hibernating phase could lead to down regulation of the opioid receptors and minimize its inhibition on hippocampal serotonergic activity. A high 5-HT activity would inhibit midbrain reticular activating system indirectly through non-serotonergic fibers, which in turn facilitate the onset or maintenance of hibernation.

Classification and evolutionary analysis of the basic helix-loop-helix gene family in the green anole lizard, Anolis carolinensis.

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Liu, Ake; Wang, Yong; Zhang, Debao; Wang, Xuhua; Song, Huifang; Dang, Chunwang; Yao, Qin; Chen, Keping

2013-08-01

Helix-loop-helix (bHLH) proteins play essential regulatory roles in a variety of biological processes. These highly conserved proteins form a large transcription factor superfamily, and are commonly identified in large numbers within animal, plant, and fungal genomes. The bHLH domain has been well studied in many animal species, but has not yet been characterized in non-avian reptiles. In this study, we identified 102 putative bHLH genes in the genome of the green anole lizard, Anolis carolinensis. Based on phylogenetic analysis, these genes were classified into 43 families, with 43, 24, 16, 3, 10, and 3 members assigned into groups A, B, C, D, E, and F, respectively, and 3 members categorized as "orphans". Within-group evolutionary relationships inferred from the phylogenetic analysis were consistent with highly conserved patterns observed for introns and additional domains. Results from phylogenetic analysis of the H/E(spl) family suggest that genome and tandem gene duplications have contributed to this family's expansion. Our classification and evolutionary analysis has provided insights into the evolutionary diversification of animal bHLH genes, and should aid future studies on bHLH protein regulation of key growth and developmental processes.

Effects of symmetrical voltage sags on squirrel-cage induction motors

Energy Technology Data Exchange (ETDEWEB)

Pedra, Joaquin; Sainz, Luis; Corcoles, Felipe [Department of Electrical Engineering, ETSEIB-UPC, Av. Diagonal, 647, 08028 Barcelona (Spain)

2007-10-15

This paper analyzes the symmetrical voltage sag consequences on the induction motor behavior when single- and double-cage models are considered, namely current and torque peaks, and speed loss. These effects depend on several variables like sag type, duration and depth. Voltage sag effects are studied by using single- and double-cage models for three motors of different rated power. The double-cage model always predicts torque and current peaks higher than those of the single-cage model. The single-cage model predicts that voltage sags can produce motor instability, whereas the double-cage model is always stable. Therefore, the double-cage model must be used for the simulation of the squirrel-cage induction motor, because the single-cage model can give erroneous results in some situations. (author)

Intrusion of soil covered uranium mill tailings by whitetail prairie dogs and Richardson's ground squirrels

International Nuclear Information System (INIS)

Shuman, R.

1984-01-01

The primary objective of the reclamation of uranium mill tailings is the long-term isolation of the matrial from the biosphere. Fossorial and semi-fossorial species represent a potentially disruptive influence as a result of their burrowing habits. The potential for intrusion was investigated with respect to two sciurids, the whitetail prairie dog (Cynomys leucurus) and Richardson's ground squirrel (Spermophilus richardsonii). Populations of prairie dogs were established on a control area, lacking a tailings layer, and two experimental areas, underlain by a waste layer, in southeastern Wyoming. Weekly measurements of prairie dog mound surface activities were conducted to demonstrate penetration, or lack thereof, of the tailings layer. Additionally, the impact of burrowing upon radon flux was determined. Limited penetration of the waste layer was noted after which frequency of inhabitance of the intruding burrow system declined. No significant changes in radon flux were detected. In another experiment, it was found that Richardson's ground squirrels burrowed to less extreme depths when confronted by mill tailings. Additional work at an inactive tailings pile in western Colorado revealed repeated intrusion through a shallow cover, and subsequent transport of radioactive material to the ground surface by prairie dogs. Radon flux from burrow entrances was significantly greater than that from undisturbed ground. Data suggested that textural and pH properties of tailings material may act to discourage repeated intrusion at some sites. 58 references

Effect of physical exercise prelabyrinthectomy on locomotor balance compensation in the squirrel monkey

Science.gov (United States)

Igarashi, M.; Ohashi, K.; Yoshihara, T.; MacDonald, S.

1989-01-01

This study examines the effectiveness of physical exercise, during a prepathology state, on locomotor balance compensation after subsequent unilateral labyrinthectomy in squirrel monkeys. An experimental group underwent 3 hr. of daily running exercise on a treadmill for 3 mo. prior to the surgery, whereas a control group was not exercised. Postoperatively, the locomotor balance function of both groups was tested for 3 mo. There was no significant difference in gait deviation counts in the acute phase of compensation. However, in the chronic compensation maintenance phase, the number of gait deviation counts was fewer in the exercise group, which showed significantly better performance stability.

Diet and food availability of the Virginia northern flying squirrel (Glaucomys sabrinus fuscus): implications for dispersal in a fragmented forest

Science.gov (United States)

Stephanie E. Trapp; Winston P. Smith; Elizabeth A. Flaherty

2017-01-01

A history of timber harvest in West Virginia has reduced red spruce (Picea rubens) forests to < 10% of their historic range and resulted in considerable habitat fragmentation for wildlife species associated with these forests. The Virginia northern flying squirrel (Glaucomys sabrinus fuscus) has been described as a red...

Differential regulation of glomerular and interstitial endothelial nitric oxide synthase expression in the kidney of hibernating ground squirrel.

Science.gov (United States)

Sandovici, Maria; Henning, Robert H; Hut, Roelof A; Strijkstra, Arjen M; Epema, Anne H; van Goor, Harry; Deelman, Leo E

2004-09-01

Hibernating animals transiently reduce renal function during their hypothermic periods (torpor), while completely restoring it during their periodical rewarming to euthermia (arousal). Moreover, structural integrity of the kidney is preserved throughout the hibernation. Nitric oxide (NO) generated by endothelial nitric oxide synthase (eNOS) is a crucial vasodilatory mediator and a protective factor in the kidney. We investigated renal NOS expression in hibernating European ground squirrels after 1 day and 7 days of torpor (torpor short, TS, and torpor long, TL, respectively), at 1.5 and at 10 h of rewarming (arousal short, AS, and arousal long, AL, respectively), and in continuously euthermic animals after hibernation (EU). For that purpose, we performed NOS activity assay, immunohistochemistry and real-time PCR analysis. Immunohistochemistry revealed a decreased glomerular eNOS expression in hibernating animals (TS, TL, AS, and AL) compared to non-hibernating animals (EU, p EU. In all methods used, torpid and aroused squirrels did not differ. These results demonstrate differential regulation of eNOS in glomeruli and interstitium of hibernating animals, which is unaffected during arousal. The differential regulation of eNOS may serve to reduce ultrafiltration without jeopardizing tubular structures during hibernation.

Accumulation of trace elements used in semiconductor industry in Formosan squirrel, as a bio-indicator of their exposure, living in Taiwan.

Science.gov (United States)

Suzuki, Yoshinari; Watanabe, Izumi; Oshida, Tatsuo; Chen, Yen-Jean; Lin, Liang-Kong; Wang, Yu-Huang; Yang, Kouh-Cheng; Kuno, Katsuji

2007-07-01

Concentrations of 17 trace elements were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) in Formosan squirrels (Callosciurus erythraeus) of Taiwan and Japan to document trace element pollution in Taiwan. High concentrations of elements used to produce semiconductors - Ga, As, Cd, In and Tl - were found in animals captured in Miaoli County, which is the nearest site to Hsinchu City, a chief city of Taiwan's semiconductor industry. Significant correlations between Ga, As, In and Tl were found in the kidney, liver, lung and muscle tissues of Taiwanese squirrels. Hierarchical cluster analysis indicated that Ga, As, In and Tl were of the same clade, indicating that Ga, As, In and Tl were discharged from an identical origin. Molar ratios of Ga/As concentration in lungs of animals captured in Miaoli resembled those of animals after intratracheal administration of particulate gallium arsenide (GaAs). This result might indicate that the higher concentrations of Ga and As in the specimens in Miaoli resulted from atmospheric exposure to GaAs.

A 3D high resolution ex vivo white matter atlas of the common squirrel monkey (Saimiri sciureus) based on diffusion tensor imaging.

Science.gov (United States)

Gao, Yurui; Parvathaneni, Prasanna; Schilling, Kurt G; Wang, Feng; Stepniewska, Iwona; Xu, Zhoubing; Choe, Ann S; Ding, Zhaohua; Gore, John C; Chen, Li Min; Landman, Bennett A; Anderson, Adam W

2016-02-27

Modern magnetic resonance imaging (MRI) brain atlases are high quality 3-D volumes with specific structures labeled in the volume. Atlases are essential in providing a common space for interpretation of results across studies, for anatomical education, and providing quantitative image-based navigation. Extensive work has been devoted to atlas construction for humans, macaque, and several non-primate species (e.g., rat). One notable gap in the literature is the common squirrel monkey - for which the primary published atlases date from the 1960's. The common squirrel monkey has been used extensively as surrogate for humans in biomedical studies, given its anatomical neuro-system similarities and practical considerations. This work describes the continued development of a multi-modal MRI atlas for the common squirrel monkey, for which a structural imaging space and gray matter parcels have been previously constructed. This study adds white matter tracts to the atlas. The new atlas includes 49 white matter (WM) tracts, defined using diffusion tensor imaging (DTI) in three animals and combines these data to define the anatomical locations of these tracks in a standardized coordinate system compatible with previous development. An anatomist reviewed the resulting tracts and the inter-animal reproducibility (i.e., the Dice index of each WM parcel across animals in common space) was assessed. The Dice indices range from 0.05 to 0.80 due to differences of local registration quality and the variation of WM tract position across individuals. However, the combined WM labels from the 3 animals represent the general locations of WM parcels, adding basic connectivity information to the atlas.

A 3D high resolution ex vivo white matter atlas of the common squirrel monkey (saimiri sciureus) based on diffusion tensor imaging

Science.gov (United States)

Gao, Yurui; Parvathaneni, Prasanna; Schilling, Kurt G.; Wang, Feng; Stepniewska, Iwona; Xu, Zhoubing; Choe, Ann S.; Ding, Zhaohua; Gore, John C.; Chen, Li min; Landman, Bennett A.; Anderson, Adam W.

2016-03-01

Modern magnetic resonance imaging (MRI) brain atlases are high quality 3-D volumes with specific structures labeled in the volume. Atlases are essential in providing a common space for interpretation of results across studies, for anatomical education, and providing quantitative image-based navigation. Extensive work has been devoted to atlas construction for humans, macaque, and several non-primate species (e.g., rat). One notable gap in the literature is the common squirrel monkey - for which the primary published atlases date from the 1960's. The common squirrel monkey has been used extensively as surrogate for humans in biomedical studies, given its anatomical neuro-system similarities and practical considerations. This work describes the continued development of a multi-modal MRI atlas for the common squirrel monkey, for which a structural imaging space and gray matter parcels have been previously constructed. This study adds white matter tracts to the atlas. The new atlas includes 49 white matter (WM) tracts, defined using diffusion tensor imaging (DTI) in three animals and combines these data to define the anatomical locations of these tracks in a standardized coordinate system compatible with previous development. An anatomist reviewed the resulting tracts and the inter-animal reproducibility (i.e., the Dice index of each WM parcel across animals in common space) was assessed. The Dice indices range from 0.05 to 0.80 due to differences of local registration quality and the variation of WM tract position across individuals. However, the combined WM labels from the 3 animals represent the general locations of WM parcels, adding basic connectivity information to the atlas.

Transcriptomic analysis of tail regeneration in the lizard Anolis carolinensis reveals activation of conserved vertebrate developmental and repair mechanisms.

Directory of Open Access Journals (Sweden)

Elizabeth D Hutchins

Full Text Available Lizards, which are amniote vertebrates like humans, are able to lose and regenerate a functional tail. Understanding the molecular basis of this process would advance regenerative approaches in amniotes, including humans. We have carried out the first transcriptomic analysis of tail regeneration in a lizard, the green anole Anolis carolinensis, which revealed 326 differentially expressed genes activating multiple developmental and repair mechanisms. Specifically, genes involved in wound response, hormonal regulation, musculoskeletal development, and the Wnt and MAPK/FGF pathways were differentially expressed along the regenerating tail axis. Furthermore, we identified 2 microRNA precursor families, 22 unclassified non-coding RNAs, and 3 novel protein-coding genes significantly enriched in the regenerating tail. However, high levels of progenitor/stem cell markers were not observed in any region of the regenerating tail. Furthermore, we observed multiple tissue-type specific clusters of proliferating cells along the regenerating tail, not localized to the tail tip. These findings predict a different mechanism of regeneration in the lizard than the blastema model described in the salamander and the zebrafish, which are anamniote vertebrates. Thus, lizard tail regrowth involves the activation of conserved developmental and wound response pathways, which are potential targets for regenerative medical therapies.

Comparison of survey techniques on detection of northern flying squirrels

Science.gov (United States)

Diggins, Corinne A.; Gilley, L. Michelle; Kelly, Christine A.; Ford, W. Mark

2016-01-01

The ability to detect a species is central to the success of monitoring for conservation and management purposes, especially if the species is rare or endangered. Traditional methods, such as live capture, can be labor-intensive, invasive, and produce low detection rates. Technological advances and new approaches provide opportunities to more effectively survey for species both in terms of accuracy and efficiency than previous methods. We conducted a pilot comparison study of a traditional technique (live-trapping) and 2 novel noninvasive techniques (camera-trapping and ultrasonic acoustic surveys) on detection rates of the federally endangered Carolina northern flying squirrel (Glaucomys sabrinus coloratus) in occupied habitat within the Roan Mountain Highlands of North Carolina, USA. In 2015, we established 3 5 × 5 live-trapping grids (6.5 ha) with 4 camera traps and 4 acoustic detectors systematically embedded in each grid. All 3 techniques were used simultaneously during 2 4-day survey periods. We compared techniques by assessing probability of detection (POD), latency to detection (LTD; i.e., no. of survey nights until initial detection), and survey effort. Acoustics had the greatest POD (0.37 ± 0.06 SE), followed by camera traps (0.30 ± 0.06) and live traps (0.01 ± 0.005). Acoustics had a lower LTD than camera traps (P = 0.017), where average LTD was 1.5 nights for acoustics and 3.25 nights for camera traps. Total field effort was greatest with live traps (111.9 hr) followed by acoustics (8.4 hr) and camera traps (9.6 hr), although processing and examination for data of noninvasive techniques made overall effort similar among the 3 methods. This pilot study demonstrated that both noninvasive methods were better rapid-assessment detection techniques for flying squirrels than live traps. However, determining seasonal effects between survey techniques and further development of protocols for both noninvasive techniques is

Generalized two axes model of a squirrel-cage induction motor for rotor fault diagnosis

Directory of Open Access Journals (Sweden)

Samir Hamdani

2008-01-01

Full Text Available A generalized two axes model of a squirrel-cage induction motor is developed This model is based on a winding function approach and the coupled magnetic circuit theory and takes into account the stator and the rotor asymmetries due to faults. This paper presents a computer simulation and experimental dynamic characteristics for a healthy induction machine, machine with one broken bar and a machine with two broken bars. The results illustrate good agreement between both simulated and experimental results. Also, the power spectral density PSD was performed to obtain a stator current spectrum.

The incredible shrinking dewlap: signal size, skin elasticity, and mechanical design in the green anole lizard (Anolis carolinensis).

Science.gov (United States)

Lailvaux, Simon P; Leifer, Jack; Kircher, Bonnie K; Johnson, Michele A

2015-10-01

The expression of male secondary sexual traits can be dynamic, changing size, shape, color, or structure over the course of different seasons. However, the factors underlying such changes are poorly understood. In male Anolis carolinensis lizards, a morphological secondary sexual signal called the dewlap changes size seasonally within individuals. Here, we test the hypothesis that seasonal changes in male dewlap size are driven by increased use and extension of the dewlap in spring and summer, when males are breeding, relative to the winter and fall. We captured male green anole lizards prior to the onset of breeding and constrained the dewlap in half of them such that it could not be extended. We then measured dewlap area in the spring, summer, and winter, and dewlap skin and belly skin elasticity in summer and winter. Dewlaps in unconstrained males increase in area from spring to summer and then shrink in the winter, whereas the dewlaps of constrained males consistently shrink from spring to winter. Dewlap skin is significantly more elastic than belly skin, and skin overall is more elastic in the summer relative to winter. These results show that seasonal changes in dewlap size are a function of skin elasticity and display frequency, and suggest that the mechanical properties of signaling structures can have important implications for signal evolution and design.

The influence of select losses components on induction squirrel-cage motor efficiency

Energy Technology Data Exchange (ETDEWEB)

Dabala, K. [Electrical Machines Dept., Electrotechnical Inst., Warsaw (Poland)

2000-07-01

There is taken into consideration the influence of measured core and friction and windage losses on induction squirrel-cage motor in this paper. This paper presents a way of exact core losses determination in full-load motor. There are also compared efficiencies obtained for three core losses values: from no-load test (IEC 34-2); from draft IEC 2G/102/CDV; from presented in this paper method. This paper presents the influence of the friction and windage losses determined from no-load test and the mechanical losses appeared under the rated speed on the efficiency, too. There is compared the influence of the core and mechanical losses sum on the efficiency dependently on the way of this losses components determination. (orig.)

Some aspects of the ecology of the Indian Giant Squirrel Ratufa indica (Erxleben, 1777 in the tropical forests of Mudumalai Wildlife Sanctuary, southern India and their conservation implications

Directory of Open Access Journals (Sweden)

N. Baskaran

2011-07-01

Full Text Available The Indian Giant Squirrel Ratufa indica, an endemic species to India, is widely distributed from the evergreen to moist and dry deciduous forests of Western and Eastern Ghats and the central Indian hills. We studied its population distribution, activity, feeding, ranging and nesting behaviour across three major habitats in the tropical forests of Mudumalai Wildlife Sanctuary, southern India, during 1998-2000 to manage the species effectively. Extensive survey of the three major habitats—tropical moist, dry deciduous and dry thorn—in the sanctuary shows that its distribution is continuous in moist and dry deciduous forests with good canopy contiguity and patchy along riverine areas in dry thorn and dry deciduous forests with sparse trees and broken canopy. Density estimates using 55 direct sightings from 199 km line transects show a mean of 2.9 (plus or minus 0.313 squirrels/km2. Daylight activity and feeding patterns assessed through 24,098 minutes of focal sampling reveal that animals feed and rest equal amounts of time. The diet constitutes seeds, bark, petioles, leaves and fruits from 25 plants, with Tectona grandis as the principal food source (41%. Its home range size varied from 0.8-1.7 ha with a mean of 1.3ha. Nesting characteristics assessed through 83 nests surveyed along 54km transects showed that the squirrel uses 15 of the 33 tree species found, with higher preference to Schleichera oleosa and Mangifera indica. Nest trees are significantly larger in height, gbh and canopy contiguity than nearest non-nest trees, which are attributed to better protection and escape from predators. Maintenance of diverse natural habitats and reduction in anthropogenic pressure are measures suggested for the conservation of giant squirrel populations in the study area.

Background and stimulus-induced patterns of high metabolic activity in the visual cortex (area 17) of the squirrel and macaque monkey

International Nuclear Information System (INIS)

Humphrey, A.L.; Hendrickson, A.E.

1983-01-01

We have used 2-deoxy-D-[ 14 C]glucose (2-DG) autoradiography and cytochrome oxidase histochemistry to examine background and stimulus-induced patterns of metabolic activity in monkey striate cortex. In squirrel monkeys (Saimiri sciureus) that binocularly or monocularly viewed diffuse white light or binocularly viewed bars of many orientations and spatial frequencies, 2-DG consumption was not uniform across the cortex but consisted of regularly spaced radial zones of high uptake. The zones extended through all laminae except IVc beta and, when viewed tangentially, formed separate patches 500 microns apart. The cytochrome oxidase stain in these animals also revealed patches of high metabolism which coincided with the 2-DG patches. Squirrel monkeys binocularly viewing vertical stripes showed parallel bands of increased 2-DG uptake in the cortex, while the cytochrome label in these animals remained patchy. When monkeys were kept in the dark during 2-DG exposure, 2-DG-labeled patches were not seen but cytochrome oxidase-positive patches remained. In macaque (Macaca nemestrina) monkeys, binocular stimulation with many orientations and spatial frequencies produced radial zones of high 2-DG uptake in layers I to IVa and VI. When viewed tangentially, these zones formed a dots-in-rows pattern with a spacing of 350 X 500 microns; cytochrome oxidase staining produced an identical pattern. Macaca differed from Saimiri in that monocular stimulation labeled alternate rows. These results indicate that there are radial zones of high background metabolism across squirrel and macaque monkey striate cortex. In Saimiri these zones do not appear to be related to an eye dominance system, while in Macaca they do. The presence of these zones of high metabolism may complicate the interpretation of 2-DG autoradiographs that result from specific visual stimuli

Defining landscape resistance values in least-cost connectivity models for the invasive grey squirrel: a comparison of approaches using expert-opinion and habitat suitability modelling.

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Stevenson-Holt, Claire D; Watts, Kevin; Bellamy, Chloe C; Nevin, Owen T; Ramsey, Andrew D

2014-01-01

Least-cost models are widely used to study the functional connectivity of habitat within a varied landscape matrix. A critical step in the process is identifying resistance values for each land cover based upon the facilitating or impeding impact on species movement. Ideally resistance values would be parameterised with empirical data, but due to a shortage of such information, expert-opinion is often used. However, the use of expert-opinion is seen as subjective, human-centric and unreliable. This study derived resistance values from grey squirrel habitat suitability models (HSM) in order to compare the utility and validity of this approach with more traditional, expert-led methods. Models were built and tested with MaxEnt, using squirrel presence records and a categorical land cover map for Cumbria, UK. Predictions on the likelihood of squirrel occurrence within each land cover type were inverted, providing resistance values which were used to parameterise a least-cost model. The resulting habitat networks were measured and compared to those derived from a least-cost model built with previously collated information from experts. The expert-derived and HSM-inferred least-cost networks differ in precision. The HSM-informed networks were smaller and more fragmented because of the higher resistance values attributed to most habitats. These results are discussed in relation to the applicability of both approaches for conservation and management objectives, providing guidance to researchers and practitioners attempting to apply and interpret a least-cost approach to mapping ecological networks.

Defining landscape resistance values in least-cost connectivity models for the invasive grey squirrel: a comparison of approaches using expert-opinion and habitat suitability modelling.

Directory of Open Access Journals (Sweden)

Claire D Stevenson-Holt

Full Text Available Least-cost models are widely used to study the functional connectivity of habitat within a varied landscape matrix. A critical step in the process is identifying resistance values for each land cover based upon the facilitating or impeding impact on species movement. Ideally resistance values would be parameterised with empirical data, but due to a shortage of such information, expert-opinion is often used. However, the use of expert-opinion is seen as subjective, human-centric and unreliable. This study derived resistance values from grey squirrel habitat suitability models (HSM in order to compare the utility and validity of this approach with more traditional, expert-led methods. Models were built and tested with MaxEnt, using squirrel presence records and a categorical land cover map for Cumbria, UK. Predictions on the likelihood of squirrel occurrence within each land cover type were inverted, providing resistance values which were used to parameterise a least-cost model. The resulting habitat networks were measured and compared to those derived from a least-cost model built with previously collated information from experts. The expert-derived and HSM-inferred least-cost networks differ in precision. The HSM-informed networks were smaller and more fragmented because of the higher resistance values attributed to most habitats. These results are discussed in relation to the applicability of both approaches for conservation and management objectives, providing guidance to researchers and practitioners attempting to apply and interpret a least-cost approach to mapping ecological networks.

Green tree frog (Hyla cinerea) and ground squirrel (Xerospermophilus spilosoma) mortality attributed to inland brevetoxin transportation at Padre Island National Seashore, Texas, 2015

Science.gov (United States)

Buttke, Danielle E.; Walker, Alicia; Huang, I-Shuo; Flewelling, Leanne; Lankton, Julia S.; Ballmann, Anne E.; Clapp, Travis; Lindsay, James; Zimba, Paul V.

2018-01-01

On 16 September 2015, a red tide (Karenia brevis) bloom impacted coastal areas of Padre Island National Seashore Park. Two days later and about 0.9 km inland, 30–40 adult green tree frogs (Hyla cinerea) were found dead after displaying tremors, weakness, labored breathing, and other signs of neurologic impairment. A rainstorm, accompanied by high winds, rough surf, and high tides, which could have aerosolized brevetoxin, occurred on the morning of the mortality event. Frog carcasses were healthy but contained significant brevetoxin in tissues. Tissue brevetoxin was also found in two dead or dying spotted ground squirrels (Xerospermophilus spilosoma) and a coyote (Canis latrans). Rainwater collected from the location of the mortality event contained brevetoxin. Mortality of green tree frog and ground squirrel mortality has not been previously attributed to brevetoxin exposure and such mortality suggested that inland toxin transport, possibly through aerosols, rainfall, or insects, may have important implications for coastal species.

Fault Diagnosis of Broken Rotor Bars in Squirrel-Cage Induction Motor of Hoister Based on Duffing Oscillator and Multifractal Dimension

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Zhike Zhao

2014-07-01

Full Text Available This paper is to propose a novel fault diagnosis method for broken rotor bars in squirrel-cage induction motor of hoister, which is based on duffing oscillator and multifractal dimension. Firstly, based on the analysis of the structure and performance of modified duffing oscillator, the end of transitional slope from chaotic area to large-scale cycle area is selected as the optimal critical threshold of duffing oscillator by bifurcation diagrams and Lyapunov exponent. Secondly, the phase transformation duffing oscillator from chaos to intermittent chaos is sensitive to the signals, whose frequency difference is quite weak from the reference signal. The spectrums of the largest Lyapunov exponents and bifurcation diagrams of the duffing oscillator are utilized to analyze the variance in different parameters of frequency. Finally, this paper is to analyze the characteristics of both single fractal (box-counting dimension and multifractal and make a comparison between them. Multifractal detrended fluctuation analysis is applied to detect extra frequency component of current signal. Experimental results reveal that the method is effective for early detection of broken rotor bars in squirrel-cage induction motor of hoister.

The Effect of Human Development on Mammal Populations of the Punta Leona Private Wildlife Refuge, Costa Rica

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Michael Van Hulle

2009-06-01

Full Text Available The effect of human development on six diurnal mammal species was studied using transects in the Punta Leona Private Wildlife Refuge, Puntarenas, Costa Rica during the dry season months of March and April 2006. Individuals/km was recorded for each species in more developed (MD (near paved roads, buildings, construction, or deforested trees and less developed areas (LD (secondary forest. The white-faced apuchin monkey (Cebus capucinus (n = 233, coatimundi (Nasua narica (n = 46, and Central American spider monkey (Ateles geoffroyi (n = 36 demonstrated a preference for less-developed habitats. The nine-banded armadillo (Dasypus novemcinctus (n = 4, tamandua (Tamandua mexicana (n = 2 and variegated squirrel (Sciurus variegatoides (n = 5 were observed infrequently. White-faced monkeys avoided construction areas, but received artificial food daily in developed areas. Coatimundis also received artificial foods daily and showed aggression towards guests. Rev. Biol. Trop. 57 (1-2: 441-449. Epub 2009 June 30.Se estudiaron seis especies de mamíferos mediante transectos durante la estación seca tardía (marzo y abril de 1996 en el Refugio de Vida Silvestre de Punta Leona, Puntarenas, Costa Rica. Se registró la cantidad de animales por km en lugares con mucho efecto humano (cerca del caminos pavimentados, edificios, construcción, y deforestación y lugares con menos efecto. El mono carablanca (Cebus capucinus (n = 233, el pizote (Nasua narica (n = 46, y el mono araña centroamericano (Ateles geoffroyi (n = 36 prefirieron lugares con menos efecto. Se observó pocos armadillos (Dasypus novemcinctus (n = 4, osos hormigueros (Tamandua mexicana (n = 2, y ardillas (Sciurus variegatoides (n = 5. Los monos carablancas y pizotes aceptan alimentos artificiales y los pizotes fueron agresivos con los turistas. Los carablancas evitan los lugares con construcciones y los caminos pavimentados.

Individual differences in zoo-housed squirrel monkeys' (Saimiri sciureus) reactions to visitors, research participation, and personality ratings.

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Polgár, Zita; Wood, Lara; Haskell, Marie J

2017-05-01

Understanding individual differences in captive squirrel monkeys is a topic of importance both for improving welfare by catering to individual needs, and for better understanding the results and implications of behavioral research. In this study, 23 squirrel monkeys (Saimiri sciureus), housed in an environment that is both a zoo enclosure and research facility, were assessed for (i) the time they spent by an observation window under three visitor conditions: no visitors, small groups, and large groups; (ii) their likelihood of participating in voluntary research; and (iii) zookeepers, ratings of personality. A Friedman's ANOVA and Wilcoxon post-hoc tests comparing mean times found that the monkeys spent more time by the window when there were large groups present than when there were small groups or no visitors. Thus, visitors do not seem to have a negative effect and may be enriching for certain individuals. Through GLMM and correlational analyses, it was found that high scores on the personality trait of playfulness and low scores on cautiousness, depression, and solitude were significant predictors of increased window approach behavior when visitors were present. The GLMM and correlational analyses assessing the links between personality traits and research participation found that low scores of cautiousness and high scores of playfulness, gentleness, affection, and friendliness, were significant predictors. The implications of these results are discussed in relation to selection bias and its potential confounding effect on cognitive studies with voluntary participation. © 2017 Wiley Periodicals, Inc.

Complementary Network-Based Approaches for Exploring Genetic Structure and Functional Connectivity in Two Vulnerable, Endemic Ground Squirrels

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Victoria H. Zero

2017-06-01

Full Text Available The persistence of small populations is influenced by genetic structure and functional connectivity. We used two network-based approaches to understand the persistence of the northern Idaho ground squirrel (Urocitellus brunneus and the southern Idaho ground squirrel (U. endemicus, two congeners of conservation concern. These graph theoretic approaches are conventionally applied to social or transportation networks, but here are used to study population persistence and connectivity. Population graph analyses revealed that local extinction rapidly reduced connectivity for the southern species, while connectivity for the northern species could be maintained following local extinction. Results from gravity models complemented those of population graph analyses, and indicated that potential vegetation productivity and topography drove connectivity in the northern species. For the southern species, development (roads and small-scale topography reduced connectivity, while greater potential vegetation productivity increased connectivity. Taken together, the results of the two network-based methods (population graph analyses and gravity models suggest the need for increased conservation action for the southern species, and that management efforts have been effective at maintaining habitat quality throughout the current range of the northern species. To prevent further declines, we encourage the continuation of management efforts for the northern species, whereas conservation of the southern species requires active management and additional measures to curtail habitat fragmentation. Our combination of population graph analyses and gravity models can inform conservation strategies of other species exhibiting patchy distributions.

Demonstration of synthesis of beta-trace protein in different tissues of squirrel monkey

Energy Technology Data Exchange (ETDEWEB)

Olsson, J E; Sandberg, M [Department of Neurology, University Hospital, S-221 85 Lund, Sweden

1975-01-01

The sites of synthesis of the low molwculat weight beta-trace protein, present in a seven times higher concentration in normal human CSF than in normal human serum, have been studied by means of a radioactive immunoprecipitation method. Adult squirrel monkey tissue were cultured in Eagle's minium essential medium in the presence of /sup 14/C-labelled valine, threonine and leucine for 24 hours. Synthesis could be demonstrated in cultures of white CNS matter, whereas cultures of grey CNS matter, peripheral nerve, skeletal muscle, kidney and ovary did not show any signs of synthesis. Some cultures of spinal cord, basal ganglia, genital organs except ovary, and liver showed a probable synthesis of beta-trace protein. By means of autoradiography, the synthesis of beta-trace protein in white CNS matter could be confirmed.

Demonstration of synthesis of beta-trace protein in different tissues of squirrel monkey

International Nuclear Information System (INIS)

Olsson, J.-E.; Sandberg, M.

1975-01-01

The sites of synthesis of the low molwculat weight beta-trace protein, present in a seven times higher concentration in normal human CSF than in normal human serum, have been studied by means of a radioactive immunoprecipitation method. Adult squirrel monkey tissue were cultured in Eagle's minium essential medium in the presence of 14 C-labelled valine, threonine and leucine for 24 hours. Synthesis could be demonstrated in cultures of white CNS matter, whereas cultures of grey CNS matter, peripheral nerve, skeletal muscle, kidney and ovary did not show any signs of synthesis. Some cultures of spinal cord, basal ganglia, genital organs except ovary, and liver showed a probable synthesis of beta-trace protein. By means of autoradiography, the synthesis of beta-trace protein in white CNS matter could be confirmed. (author)

The role of feral mammals on wildlife infectious disease prevalence in two nature reserves within Mexico City limits.

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Suzán, Gerardo; Ceballos, Gerardo

2005-09-01

Wild and feral medium-sized mammals were live trapped at two natural protected areas within the Mexico City limits to determine antibody prevalence for the most common infectious diseases (rabies, toxoplasmosis, and canine parvovirus) in dogs and cats. Mammals were trapped during the dry (March-April) and rainy seasons (July-August) of 1996 and 1997. A total of 68 individuals were captured, representing 8 species: opossums (Didelphis virginiana), ringtails (Bassariscus astutus), spotted skunks (Spilogale gracilis), weasels (Mustela frenata), rock squirrels (Spermophilus variegatus), Mexican gray squirrels (Sciurus aureogaster), feral cats (Felis catus), and feral dogs (Canis familiaris). There was marked seroprevalence for parvovirus (86.6%) and lower seroprevalences for both toxoplasma (23.9%) and rabies (17.9%). There were no significant prevalence differences among mammals in both protected areas, which were of contrasting size and isolation (i.e., small and isolated versus large and nonisolated). We suggest that high seroprevalence of these three infectious agents in wild mammals is a result of the high densities of feral dogs and cats in the two areas sampled. Feral dogs are able to maintain the infectious agents in these localities regardless of the protected area size and isolation. However, the native mammals of the small and isolated reserve are more vulnerable to infectious diseases because of small population size and genetic bottlenecks. Our results indicate that natural areas in and around Mexico City are a refugium for latent infectious agents, several of which are zoonotic. These findings suggest that conservation measures, such as eradication of feral mammals and vaccination programs, in the protected areas and surrounding areas could be beneficial.

Metabolism of 1,2,3,4-, 1,2,3,5-, and 1,2,4,5-tetrachlorobenzene in the squirrel monkey

International Nuclear Information System (INIS)

Schwartz, H.; Chu, I.; Villeneuve, D.C.; Benoit, F.M.

1987-01-01

The metabolism of three tetrachlorobenzene isomers (TeCB) was investigated in the squirrel monkey. The animals were administered orally 6 single doses of 14 C-labeled 1,2,3,4-, 1,2,4,5-, or 1,2,3,5-tetrachlorobenzene over a 3-wk period at levels ranging from 50 to 100 mg/kg body weight (b.w) and kept in individual metabolism cages to collect urine and feces for radioassay. Approximately 38% (1,2,3,4-TeCB), 36% (1,2,3,5-TeCB), and 18% (1,2,4,5-TeCB) of the doses were excreted respectively in the feces 48 h post administration. In monkeys dosed with 1,2,3,4-TeCB, unchanged compound accounted for 50% of the fecal radioactivity. Unchanged compound accounted for more than 50% of the fecal radioactivity found in the monkeys dosed with 1,2,3,5-TeCB. The fecal metabolites were identified in both groups. No metabolites were detected in the feces of monkeys dosed with 1,2,4,5-TeCB. While the fecal route represented the major route of excretion for 1,2,3,4-TeCB, the other two isomers were eliminated exclusively in the feces. The above data in the squirrel monkey are different from those obtained with the rat and the rabbit, and demonstrate the different metabolic pathways for the isomers

Evaluation of neonatal squirrel monkeys receiving tritiated water throughout gestation

International Nuclear Information System (INIS)

Jones, D.C.L.; Krebs, J.S.; Sasmore, D.P.; Mitoma, C.

1980-01-01

Pregnant squirrel monkeys received tritiated water (HTO) in the drinking water throughout gestation at levels ranging from 16 to 1000 times the permissible level for human consumption (0.003 μCi/ml), resulting in mean body water HTO levels ranging from 0.05 to 3.1 μCi/ml. There were no discernible effects of HTO administration on the newborn progeny in terms of body weight, body dimensions, selected organ weights (brain, heart, adrenal, kidney, liver, spleen), hematologic patterns, and histology of selected organs and tissues (adrenal, kidney, liver, lung, brain, pancreas, jejunum, pituitary, spleen, testes, thymus, skin) other than ovaries. The number of primary oocytes in female progeny decreased markedly with increasing levels of HTO in maternal drinking water. Quantitative analysis of neonate ovaries, testes, brain tissue, and retinal tissue is in progress. No effects of HTO administration on maternal body weight, gestation time, or maintenance of pregnancy to full term were observed. Body weights of HTO-treated inseminated females that did not deliver were less than control weights, but the lack of dose dependence implies that this effect may have been associated with a stimulus characteristic of the HTO administration rather than with irradiation

Relative importance of temperature and diet to larval development and adult size of the winter stonefly, Soyedina carolinensis (Plecoptera: Nemouridae)

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Sweeney, B.W.; Vannote, R.L.; Dodds, P.J.

1986-02-01

Soyedina carolinensis Claassen, a leaf shredding stonefly, was reared in a series of three laboratory experiments from early instar to adult on different species of deciduous leaves and at various constant and fluctuating temperature regimes. Experiment 1, which involved rearing larvae on fourteen different leaf diets at ambient stream temperatures, showed that diet significantly affected larval growth and adult size but did not affect overall developmental time. Experiment 2, which involved rearing larvae on five different leaf diets at each of three fluctuating temperature regimes, showed that: adding 6/sup 0/C to the normal temperature regime of WCC was lethal to 99% of the larvae regardless of diet; and warming WCC by 3/sup 0/C did not affect developmental time but did significantly reduce adult size relative to adults reared at WCC temperatures on certain diets. Experiment 3, which involved rearing larvae on five different leaf diets at each of five constant temperatures showed that: temperature significantly affected the mortality, growth, and development time of larvae whereas diet only affected larval growth and mortality; temperatures at or near 10/sup 0/C yielded maximum larval growth and survival for most diets; at 5/sup 0/C, larval mortality was high and growth was low resulting in a few small adults for most diets; larval mortality was at or near 100% at 15/sup 0/C regardless of diet; and no larvae survived at 20 and 25/sup 0/C.

Morphology and mitochondrial phylogenetics reveal that the Amazon River separates two eastern squirrel monkey species: Saimiri sciureus and S. collinsi.

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Mercês, Michelle P; Lynch Alfaro, Jessica W; Ferreira, Wallax A S; Harada, Maria L; Silva Júnior, José S

2015-01-01

Saimiri has a complicated taxonomic history, and there is continuing disagreement about the number of valid taxa. Despite these controversies, one point of consensus among morphologists has been that the eastern Amazonian populations of squirrel monkeys form a single terminal taxon, Saimiri sciureus sciureus (Linnaeus, 1758). This group is distributed to both the north and south of the middle to lower Amazon River and in the Marajó Archipelago. However, a recent molecular study by Lavergne and colleagues suggested that the Saimiri sciureus complex (comprised of S. s. sciureus sensu lato, S. s. albigena, S. s. macrodon, and S. s. cassiquiarensis) was paraphyletic. The discordance between morphological and molecular studies prompted us to conduct a new multidisciplinary analysis, employing a combination of morphological, morphometric, and molecular markers. Our results suggest the currently recognized taxon S. s. sciureus contains two distinct species, recognized by the Phylogenetic Species Concept: Saimiri sciureus (Linnaeus, 1758) and Saimiri collinsi Osgood, 1916. East Amazonian squirrel monkeys north of the Amazon have a gray crown (S. sciureus), and south of the Amazon, the crown is yellow (S. collinsi). Morphometric measurements also clearly distinguish between the two species, with the most important contributing factors including width across upper canines for both sexes. For males, the mean zygomatic breadth was significantly wider in S. sciureus compared to S. collinsi, and for females, the width across the upper molars was wider in S. sciureus compared to S. collinsi. Mitochondrial phylogenetic analyses support this separation of the eastern Amazonian squirrel monkeys into two distinct taxa, recovering one clade (S. sciureus) distributed to the north of the Amazon River, from the Negro River and Branco River to the Guiana coast and the Brazilian state of Amapá, and another clade (S. collinsi) south of the Amazon River, from the region of the Tapaj

Evaluation of neonate squirrel monkeys receiving tritiated water throughout gestation

International Nuclear Information System (INIS)

Jones, D.C.L.

1978-01-01

The effect of receiving tritiated water (HTO) throughout gestation on the developing primate was assessed by administering HTO to adult female squirrel monkeys (Saimiri sciureus) as the only source of drinking water beginning with the day of insemination and continuing throughout pregnancy. For the control (tap water) and six experimental groups, the mean urinary tritium concentrations in females delivering full-term progeny were <0.004, 0.05, 0.16, 0.33, 0.75, 1.61, and 3.09 microcuries/ml. Positive bioassays for pregnancy were observed in about half of 277 inseminated females. Among pregnant females, the full-term delivery rate was 36%, the abortion rate was 7%, and the resorption rate was 58% with no discernible effect of HTO administration on any of these parameters. The 46 full-term progeny were evaluated within 2 days of birth. No effects of HTO administration were observed in terms of gestation period (median 153 days, range 141-158 days), sex distribution, body weight, body dimensions, selected organ weights, histology (except gonads), or hematologic pattern. The number of primary oocytes in female progeny decreased markedly within increasing concentrations of tritium. Specific quantification of this effect and evaluation of the neonate testes is in progress

Predictive Value of Parkinsonian Primates in Pharmacologic Studies: A Comparison between the Macaque, Marmoset, and Squirrel Monkey.

Science.gov (United States)

Veyres, Nicolas; Hamadjida, Adjia; Huot, Philippe

2018-05-01

The 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned primate is the gold-standard animal model of Parkinson disease (PD) and has been used to assess the effectiveness of experimental drugs on dyskinesia, parkinsonism, and psychosis. Three species have been used in most studies-the macaque, marmoset, and squirrel monkey-the last much less so than the first two species; however, the predictive value of each species at forecasting clinical efficacy, or lack thereof, is poorly documented. Here, we have reviewed all the published literature detailing pharmacologic studies that assessed the effects of experimental drugs on dyskinesia, parkinsonism, and psychosis in each of these species and have calculated their predictive value of success and failure at the clinical level. We found that, for dyskinesia, the macaque has a positive predictive value of 87.5% and a false-positive rate of 38.1%, whereas the marmoset has a positive predictive value of 76.9% and a false-positive rate of 15.6%. For parkinsonism, the macaque has a positive predictive value of 68.2% and a false-positive rate of 44.4%, whereas the marmoset has a positive predictive value of 86.9% and a false-positive rate of 41.7%. No drug that alleviates psychosis in the clinic has shown efficacy at doing so in the macaque, whereas the marmoset has 100% positive predictive value. The small number of studies conducted in the squirrel monkey precluded us from calculating its predictive efficacy. We hope our results will help in the design of pharmacologic experiments and will facilitate the drug discovery and development process in PD. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

The operation of a single-sided linear induction motor with squirrel-cage and solid-steel reaction rails

Science.gov (United States)

Eastham, A. R.; Katz, R. M.

1980-09-01

Two test programs have been conducted to evaluate the performance of a single-sided linear induction motor with a squirrel-cage reaction rail and with a solid steel reaction rail. A 1.73-m-long six-pole stator interacted with the rails mounted on the rim of a 7.6-m-diam wheel. A 64-channel data acquisition system allowed tests to be performed over a wide range of operating conditions at speeds up to 20 m/sec. Typical test results which compare and contrast the mechanical, electrical and magnetic behavior of the SLIMs are presented. The test data are being used to assess the SLIM as an integrated suspension/propulsion system and for other transportation applications.

Reproductive phenology of a food-hoarding mast-seed consumer: resource- and density-dependent benefits of early breeding in red squirrels.

Science.gov (United States)

Williams, Cory T; Lane, Jeffrey E; Humphries, Murray M; McAdam, Andrew G; Boutin, Stan

2014-03-01

The production of offspring by vertebrates is often timed to coincide with the annual peak in resource availability. However, capital breeders can extend the energetic benefits of a resource pulse by storing food or fat, thus relaxing the need for synchrony between energy supply and demand. Food-hoarding red squirrels (Tamiasciurus hudsonicus) breeding in the boreal forest are reliant on cones from a masting conifer for their nutrition, yet lactation is typically completed before the annual crop of cones is available for consumption such that peaks in energy supply and demand are not synchronized. We investigated the phenological response of red squirrels to annual variation in environmental conditions over a 20-year span and examined how intra- and inter-annual variation in the timing of reproduction affected offspring recruitment. Reproductive phenology was strongly affected by past resource availability with offspring born earlier in years following large cone crops, presumably because this affected the amount of capital available for reproduction. Early breeders had higher offspring survival and were more likely to renest following early litter loss when population density was high, perhaps because late-born offspring are less competitive in obtaining a territory when vacancies are limited. Early breeders were also more likely to renest after successfully weaning their first litter, but renesting predominantly occurred during mast years. Because of their increased propensity to renest and the higher survival rates of their offspring, early breeders contribute more recruits to the population but the advantage of early breeding depends on population density and resource availability.

Comparative Morphology and Histology of the Nasal Fossa in Four Mammals: Gray Squirrel, Bobcat, Coyote, and White-Tailed Deer.

Science.gov (United States)

Yee, Karen K; Craven, Brent A; Wysocki, Charles J; Van Valkenburgh, Blaire

2016-07-01

Although the anatomy of the nasal fossa is broadly similar among terrestrial mammals, differences are evident in the intricacies of nasal turbinal architecture, which varies from simple scroll-like to complex branching forms, and in the extent of nonsensory and olfactory epithelium covering the turbinals. In this study, detailed morphological and immunohistochemical examinations and quantitative measurements of the turbinals and epithelial lining of the nasal fossa were conducted in an array of species that include the gray squirrel, bobcat, coyote, and white-tailed deer. Results show that much more of the nose is lined with olfactory epithelium in the smallest species (gray squirrel) than in the larger species. In two species with similar body masses, bobcat and coyote, the foreshortened felid snout influences turbinal size and results in a decrease of olfactory epithelium on the ethmoturbinals relative to the longer canine snout. Ethmoturbinal surface area exceeds that of the maxilloturbinals in all four sampled animals, except the white-tailed deer, in which the two are similar in size. Combining our results with published data from a broader array of mammalian noses, it is apparent that olfactory epithelial surface area is influenced by body mass, but is also affected by aspects of life history, such as diet and habitat, as well as skull morphology, itself a product of multiple compromises between various functions, such as feeding, vision, and cognition. The results of this study warrant further examination of other mammalian noses to broaden our evolutionary understanding of nasal fossa anatomy. Anat Rec, 299:840-852, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Autoradiographic studies on the effect of allopurinol on 14C-hydpoxanthine metabolism in the squirrel monkey

International Nuclear Information System (INIS)

Matsunaga, Yoshimasa; Miyazaki, Hisashi; Hashimoto, Masahisa

1980-01-01

The Effect of orally given allopurinol on the distribution of intravenously administered 14 C-hypoxanthine radioactivity was studied in squirrel monkeys 8 hr after administration of the label by the whole body autoradiography. Although the distribution of radioactivity in the normal and allopurinol-treated animals was essentially similar to each other, more intense radioactivity was noted in the latter monkey; salvage of 14 C-hypoxanthine was enhanced. Similarly to our previous observation in mice, significant radioactivity in monkeys was seen in tissues undergoing rapid nucleic acid synthesis except for slight species differences in some organs. 14 C-Allantoin alone was the urinary metabolite of the hypoxanthine in the normal monkey whereas significant amounts of 14 C-hypoxanthine and 14 C-xanthine as well were detected in the urine of the drug-treated animal. (author)

Activity budget, diet, and use of space by two groups of squirrel monkeys (Saimiri sciureus) in eastern Amazonia.

Science.gov (United States)

Pinheiro, Tatyana; Ferrari, Stephen F; Lopes, Maria Aparecida

2013-07-01

Squirrel monkeys (Saimiri spp.) are widely distributed in the Amazon basin. This study describes the ecological and behavioral patterns of two social groups of S. sciureus in forests adjacent to the Tucuruí hydroelectric reservoir in eastern Amazonia, including range size, activity budgets, and composition of the diet. The groups were monitored at Base 4 (group B4) and Germoplasma Island (group GI). Quantitative behavioral data were collected using instantaneous scan sampling to record behavior, substrate use, and height. Home ranges were delimited using a GPS to determine group position after each 50 m of movement. Home ranges were 75.0 ha for group B4 (39 members) and 77.5 ha for group GI (32 members). The use of vertical strata was well defined, with a marked preference for the middle and lower levels of the canopy. The activity budgets of both groups were typical of those of other squirrel monkeys and were dominated by foraging (B4 = 48.7 %; GI = 49.6 %), moving (both groups 28.9 %), and feeding (B4 = 14.6 %; GI = 12.4 %). Resting was rare (B4 = 3.5 %; GI = 2.6 %) and less common than social behavior (B4 = 4.3 %; GI = 6.4 %). The diet of both groups was dominated by plant material (B4 = 70.7 % of feeding records; GI = 71.4 %), which is in contrast with the more insectivorous diets recorded for Saimiri at other sites. Group GI spent more time foraging during the dry season, whereas group B4 spent more time in the rainy season when the consumption of fruit increased (significantly, in the case of group GI). The less insectivorous diet of these groups may be due to a number of factors, including the unique habitat configuration at the site and reduced hydrological stress due to the proximity of the reservoir.

Life on the edge: squirrel-cage fringe fields and their effects in the MBE-4 combiner experiment

International Nuclear Information System (INIS)

Fawley, W.M.

1996-02-01

The MBE-4 combiner experiment employs an electrostatic combined-function focusing/bending element, the so-called ''squirrel-cage'' just before the actual merging region. There has been concern that non-linear fields, primarily in the fringe regions at the beginning and end of the cage, may be strong enough to lead to significant emittance degradation. This note present the results of numerical calculations which determined the anharmonic, non-linear components of the 3D fields in the cage and the resultant, orbit-integrated effects upon the MBE-4 beamlets. We find that while the anharmonic effects are small compared to the dipole deflection, the resultant transverse emittance growth is significant when compared to the expected value of the initial emittance of the individual beamlets

[14C]2-deoxyglucose uptake in ground squirrel brain during hibernation

International Nuclear Information System (INIS)

Kilduff, T.S.; Sharp, F.R.; Heller, H.C.

1982-01-01

Autoradiographic patterns of [14C]2-deoxyglucose uptake are described throughout the brains of hibernating and euthermic ground squirrels. Autoradiographs of the brains of hibernating animals are generally homogeneous in comparison to euthermic animals; hence, the relative 2-deoxyglucose uptake (R2DGU) of gray to white matter for the majority of the 85 neural structures examined decreases during hibernation. Two categories of structures are identified as potentially important in hibernation: (1) structures that have the highest R2DGU during hibernation (cochlear nucleus, paratrigeminal nucleus, and superior colliculus) and (2) structures that undergo the least reduction in R2DGU in the transition from euthermia to hibernation (suprachiasmatic nucleus and lateral septal nucleus). The percentage of reduction in R2DGU that a structure undergoes in the transition from euthermia to hibernation is proportional to the R2DGU of that structure during euthermia. The suprachiasmatic, paratrigeminal, and cochlear nuclei undergo less of a reduction than would be predicted from this relationship and may be particularly important during hibernation. Sensory nuclei that receive primary afferent projections are among the structures with the highest R2DGU during hibernation. These metabolically active structures may be responsible for the sensitivity of the hibernator to environmental stimuli

A thermal and electrical dynamic mathematical model for squirrel cage induction motors; Modelamento matematico dinamico termico e eletrico de motores de inducao

Energy Technology Data Exchange (ETDEWEB)

Sousa, Ronaldo Martins de

1996-01-01

A thermal and electrical dynamic mathematical model for squirrel cage induction motors is presented. The electrical model is described by Park equation and the torque equation, while the thermal model is described by a system of four first order differential equations that represent the motor heat transfer process. The model presented can be used to determine thermal and electrical performance for any operation condition. However, it is suitable mainly for machines operating under continuously transient condition. The presented mathematical model also incorporate variation of rotor winding electrical parameters due to skin effect. (author)

Effects of L-DOPA on aggressive behavior and central monoaminergic activity in the lizard Anolis carolinensis, using a new method for drug delivery.

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Höglund, Erik; Korzan, Wayne J; Watt, Michael J; Forster, Gina L; Summers, Tangi R; Johannessen, Helga Falch; Renner, Kenneth J; Summers, Cliff H

2005-01-06

The dopamine (DA) precursor, L-DOPA (500 microg), was injected into living crickets, which were ingested (one each) by adult male Anolis carolinensis. This method of delivery elevated plasma L-DOPA and DA concentrations by approximately 1000-fold. In contrast, plasma epinephrine (Epi) and norepinephrine (NE) were not influenced by L-DOPA treatment, although they were elevated following the consumption of the cricket. Lizards that ingested L-DOPA treated crickets had elevated L-DOPA in all brain regions measured, with DA and/or DOPAC also increased significantly in most brain regions studied. Despite increased DA levels in the striatum and nucleus accumbens as a response to L-DOPA, the treatment had no influence on general motor activity. Central serotonin, NE, and Epi systems were not affected in any brain region by oral L-DOPA treatment. In addition, aggression was inhibited by this dose of L-DOPA, even though there was no effect on serotonergic systems. This is surprising because controlling aggressive behavior is usually considered the province of serotonergic activity. Aggression was measured before and after treatment, and while saline-treated lizards retained the full vigor of aggressive activity, those fed a cricket injected with L-DOPA were only one-third as aggressive after treatment. As L-DOPA treatment did not affect general motor activity, the effect appears to be directly associated with aggression. This is supported by the observation that L-DOPA treatment delayed latency to eyespot darkening, which predicts the latency to aggression.

Home-range use patterns and movements of the Siberian flying squirrel in urban forests: Effects of habitat composition and connectivity.

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Mäkeläinen, Sanna; de Knegt, Henrik J; Ovaskainen, Otso; Hanski, Ilpo K

2016-01-01

Urbanization causes modification, fragmentation and loss of native habitats. Such landscape changes threaten many arboreal and gliding mammals by limiting their movements through treeless parts of a landscape and by making the landscape surrounding suitable habitat patches more inhospitable. Here, we investigate the effects of landscape structure and habitat availability on the home-range use and movement patterns of the Siberian flying squirrel (Pteromys volans) at different spatial and temporal scales. We followed radio-tagged individuals in a partly urbanized study area in Eastern Finland, and analysed how landscape composition and connectivity affected the length and speed of movement bursts, distances moved during one night, and habitat and nest-site use. The presence of urban habitat on movement paths increased both movement lengths and speed whereas nightly distances travelled by males decreased with increasing amount of urban habitat within the home range. The probability of switching from the present nest site to another nest site decreased with increasing distance among the nest sites, but whether the nest sites were connected or unconnected by forests did not have a clear effect on nest switching. Flying squirrels preferred to use mature forests for their movements at night. Our results suggest that the proximity to urban habitats modifies animal movements, possibly because animals try to avoid such habitats by moving faster through them. Urbanization at the scale of an entire home range can restrict their movements. Thus, maintaining a large enough amount of mature forests around inhabited landscape fragments will help protect forest specialists in urban landscapes. The effect of forested connections remains unclear, highlighting the difficulty of measuring and preserving connectivity in a species-specific way.

Certain biochemical changes in the trachea, lungs, and heart of squirrels exposed to three principal air pollutants

Energy Technology Data Exchange (ETDEWEB)

Rana, S V; Gautam, R K; Agrawal, V P

1979-01-01

The fate of total lipids, proteins and carbohydrates in the trachea, lungs, and heart of the common ground squirrel, Funambulus pennanti, have been determined after separate exposure to three principal air pollutants, carbon monoxide (CO), sulphur dioxide (SO/sub 2/), and nitrogen dioxide (NO/sub 2/). Exposure to all of these gases produced edematous conditions; however, the moisture content of heart muscle was reduced. Carbon monoxide (CO) and NO/sub 2/ are more toxic to pulmonary lipids than SO/sub 2/. The lipid of the heart decreased, least effects noted with SO/sub 2/ treatment. Mechanical properties of the lungs were changed by alteration of the lung lipids causing changes in the surface tension. Changes in protein content were caused by altered membrane permeability. Comparative data on the carbohydrates indicated adverse effects by the pollutants.

Feeding success of Lutzomyia evansi (Diptera: Psychodidae) experimentally exposed to small mammal hosts in an endemic focus of Leishmania chagasi in northern Colombia.

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Adler, Gregory H; Becerra, María Teresa; Travi, Bruno L

2003-12-01

Lutzomyia evansi is the vector of Leishmania chagasi in northern Colombia. Differences in feeding success were revealed, when this phlebotomine sand fly was fed on five species of small mammal hosts from an endemic focus of visceral leishmaniasis. In each trial, 50 female sand flies were provided access to similar-sized depilated areas of the hind foot of each of 44 individual mammals and allowed to feed for 30 minutes. The number of engorged sand flies was counted at the end of each trial and compared among host species by analysis of variance and Tukey's multiple comparisons test. Sand flies fed least successfully on Sciurus granatensis, a common squirrel in the endemic area. It has not been found infected with L. chagasi. Intermediate numbers of sand flies engorged on Heteromys anomalus and Zygodontomys brevicauda, but these two mammals have not been found infected with L. chagasi and are not expected to be important in transmission. Sand flies fed most successfully on Didelphis marsupialis and Proechimys canicollis. These are the two most abundant mammals in the endemic area and frequently are infected. Results provided further evidence that these two species are the wild mammals with the greatest impact on transmission of L. chagasi in northern Colombia.

Metabolic hormone FGF21 is induced in ground squirrels during hibernation but its overexpression is not sufficient to cause torpor.

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Bethany T Nelson

Full Text Available Hibernation is a natural adaptation that allows certain mammals to survive physiological extremes that are lethal to humans. Near freezing body temperatures, heart rates of 3-10 beats per minute, absence of food consumption, and depressed metabolism are characteristic of hibernation torpor bouts that are periodically interrupted by brief interbout arousals (IBAs. The molecular basis of torpor induction is unknown, however starved mice overexpressing the metabolic hormone fibroblast growth factor 21 (FGF21 promote fat utilization, reduce body temperature, and readily enter torpor-all hallmarks of mammalian hibernation. In this study we cloned FGF21 from the naturally hibernating thirteen-lined ground squirrel (Ictidomys tridecemlineatus and found that levels of FGF21 mRNA in liver and FGF21 protein in serum are elevated during hibernation torpor bouts and significantly elevated during IBAs compared to summer active animals. The effects of artificially elevating circulating FGF21 concentrations 50 to 100-fold via adenoviral-mediated overexpression were examined at three different times of the year. This is the first time that a transgenic approach has been used in a natural hibernator to examine mechanistic aspects of hibernation. Surgically implanted transmitters measured various metrics of the hibernation phenotype over a 7-day period including changes in motor activity, heart rate and core body temperature. In April fed-state animals, FGF21 overexpression decreased blood insulin and free fatty acid concentrations, effects similar to those seen in obese mice. However, elevated FGF21 concentrations did not cause torpor in these fed-state animals nor did they cause torpor or affect metabolic parameters in fasted-state animals in March/April, August or October. We conclude that FGF21 is strongly regulated during torpor and IBA but that its overexpression is not sufficient to cause torpor in naturally hibernating ground squirrels.

Emergence of Cryptosporidium hominis Monkey Genotype II and Novel Subtype Family Ik in the Squirrel Monkey (Saimiri sciureus) in China.

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Liu, Xuehan; Xie, Na; Li, Wei; Zhou, Ziyao; Zhong, Zhijun; Shen, Liuhong; Cao, Suizhong; Yu, Xingming; Hu, Yanchuan; Chen, Weigang; Peng, Gangneng

2015-01-01

A single Cryptosporidium isolate from a squirrel monkey with no clinical symptoms was obtained from a zoo in Ya'an city, China, and was genotyped by PCR amplification and DNA sequencing of the small-subunit ribosomal RNA (SSU rRNA), 70-kDa heat shock protein (HSP70), Cryptosporidium oocyst wall protein, and actin genes. This multilocus genetic characterization determined that the isolate was Cryptosporidium hominis, but carried 2, 10, and 6 nucleotide differences in the SSU rRNA, HSP70, and actin loci, respectively, which is comparable to the variations at these loci between C. hominis and the previously reported monkey genotype (2, 3, and 3 nucleotide differences). Phylogenetic studies, based on neighbor-joining and maximum likelihood methods, showed that the isolate identified in the current study had a distinctly discordant taxonomic status, distinct from known C. hominis and also from the monkey genotype, with respect to the three loci. Restriction fragment length polymorphisms of the SSU rRNA gene obtained from this study were similar to those of known C. hominis but clearly differentiated from the monkey genotype. Further subtyping was performed by sequence analysis of the gene encoding the 60-kDa glycoprotein (gp60). Maximum homology of only 88.3% to C. hominis subtype IdA10G4 was observed for the current isolate, and phylogenetic analysis demonstrated that this particular isolate belonged to a novel C. hominis subtype family, IkA7G4. This study is the first to report C. hominis infection in the squirrel monkey and, based on the observed genetic characteristics, confirms a new C. hominis genotype, monkey genotype II. Thus, these results provide novel insights into genotypic variation in C. hominis.

Sliding Mode Control of a Variable- Speed Wind Energy Conversion System Using a Squirrel Cage Induction Generator

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Mohamed Zribi

2017-05-01

Full Text Available This paper deals with the control of a variable-speed wind energy conversion (WEC system using a squirrel cage induction generator (SCIG connected to the grid through a back-to-back three phase (AC-DC-AC power converter. The sliding mode control technique is used to control the WEC system. The objective of the controllers is to force the states of the system to track their desired states. One controller is used to regulate the generator speed and the flux so that maximum power is extracted from the wind. Another controller is used to control the grid side converter, which controls the DC bus voltage and the active and reactive powers injected into the grid. The performance of the controlled wind energy conversion system is verified through MATLAB simulations, which show that the controlled system performs well.

Differential effects of presynaptic versus postsynaptic adenosine A2A receptor blockade on Δ9-tetrahydrocannabinol (THC) self-administration in squirrel monkeys.

Science.gov (United States)

Justinová, Zuzana; Redhi, Godfrey H; Goldberg, Steven R; Ferré, Sergi

2014-05-07

Different doses of an adenosine A2A receptor antagonist MSX-3 [3,7-dihydro-8-[(1E)-2-(3-ethoxyphenyl)ethenyl]-7 methyl-3-[3-(phosphooxy)propyl-1-(2 propynil)-1H-purine-2,6-dione] were found previously to either decrease or increase self-administration of cannabinoids delta-9-tetrahydrocannabinol (THC) or anandamide in squirrel monkeys. It was hypothesized that the decrease observed with a relatively low dose of MSX-3 was related to blockade of striatal presynaptic A2A receptors that modulate glutamatergic neurotransmission, whereas the increase observed with a higher dose was related to blockade of postsynaptic A2A receptors localized in striatopallidal neurons. This hypothesis was confirmed in the present study by testing the effects of the preferential presynaptic and postsynaptic A2A receptor antagonists SCH-442416 [2-(2-furanyl)-7-[3-(4-methoxyphenyl)propyl]-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine] and KW-6002 [(E)-1, 3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione], respectively, in squirrel monkeys trained to intravenously self-administer THC. SCH-442416 produced a significant shift to the right of the THC self-administration dose-response curves, consistent with antagonism of the reinforcing effects of THC. Conversely, KW-6002 produced a significant shift to the left, consistent with potentiation of the reinforcing effects of THC. These results show that selectively blocking presynaptic A2A receptors could provide a new pharmacological approach to the treatment of marijuana dependence and underscore corticostriatal glutamatergic neurotransmission as a possible main mechanism involved in the rewarding effects of THC.

Stochastic population dynamics of a montane ground-dwelling squirrel.

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Jeffrey A Hostetler

Full Text Available Understanding the causes and consequences of population fluctuations is a central goal of ecology. We used demographic data from a long-term (1990-2008 study and matrix population models to investigate factors and processes influencing the dynamics and persistence of a golden-mantled ground squirrel (Callospermophilus lateralis population, inhabiting a dynamic subalpine habitat in Colorado, USA. The overall deterministic population growth rate λ was 0.94±SE 0.05 but it varied widely over time, ranging from 0.45±0.09 in 2006 to 1.50±0.12 in 2003, and was below replacement (λ<1 for 9 out of 18 years. The stochastic population growth rate λ(s was 0.92, suggesting a declining population; however, the 95% CI on λ(s included 1.0 (0.52-1.60. Stochastic elasticity analysis showed that survival of adult females, followed by survival of juvenile females and litter size, were potentially the most influential vital rates; analysis of life table response experiments revealed that the same three life history variables made the largest contributions to year-to year changes in λ. Population viability analysis revealed that, when the influences of density dependence and immigration were not considered, the population had a high (close to 1.0 in 50 years probability of extinction. However, probability of extinction declined to as low as zero when density dependence and immigration were considered. Destabilizing effects of stochastic forces were counteracted by regulating effects of density dependence and rescue effects of immigration, which allowed our study population to bounce back from low densities and prevented extinction. These results suggest that dynamics and persistence of our study population are determined synergistically by density-dependence, stochastic forces, and immigration.

[Fleas community in introduced Siberian chipmunks (Tamias sibiricus Laxmann) in Forest of Sénart, France].

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Pisanu, B; Marmet, J; Beaucournu, J C; Chapuis, J L

2008-03-01

We examined the fleas community in an introduced population of Siberian chipmunks, Tamias sibiricus, between 2005 and 2007, in the Forest of Sénart (Essonne, France). We collected and identified 383 fleas on 463 chipmunks (total: 1,891 captures on 471 chipmunks). In 2005, 120 fleas were also collected on 65 bank voles, Clethrionomys glareolus, and on 25 wood mice, Apodemus sylvaticus, trapped within the same area. Ceratophyllus sciurorum sciurorum formed 73.6% of the chipmunks' flea community, with an annual prevalence (P) ranging between 8 and 13% and a mean intensity (I) ranging between 1.1 and 1.6 fleas per individual. Among the six other species infecting this Sciurid, Ctenophthalmus agyrtes impavidus constituted 17.2% (P: 1.6-2.2%; I: 1.1-2.6), and Megabothris turbidus 8.1% (P: 0.8-1.9%; I: 1.0-1.4) of the flea community, respectively. These last two species represented respectively 60.8% and 36.6% of the flea community on the bank vole and the wood mouse. Originated from Asia, chipmunks did not import any flea species to Sénart, probably because they were used as pets before their release in the wild. Abundance in C. s. sciurorum increased with adult chipmunk density and with juvenile density in summer. On adult chipmunks C. s. sciurorum tented to decrease with increasing abundance of red squirrels (Sciurus vulgaris]. Moreover, the two other flea species mainly infected young chipmunks during the fall, and their number was not related to chipmunk density. However, the distribution of species within the flea community became more balanced with increase juvenile chipmunk density. Overall, these results indicate that the close phyletic relationship between chipmunks and red squirrels contributed in the acquisition and the spread of fleas by chipmunks. Primary and secondary hosts densities, their habitat use, and more specifically burrowing activities and tree canopy use, also played a role in the spread of fleas on chipmunks.

Osteology and chondrocranial morphology of Gastrophryne carolinensis (Anura: Microhylidae, with a review of the osteological diversity of New World microhylids

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Linda Trueb

2011-12-01

Full Text Available Microhylidae is a large, cosmopolitan anuran family. Recent molecular analyses have demonstrated the monophyly of the family—a conclusion that is supported by the larval morphology, coupled with the unique mode of tongue protrusion in adults, and a suite of osteological and myological characters seemingly associated with this innovation in feeding. Despite this functional constraint, osteological diversity probably exceeds that of any other anuran family, and this diversity is especially evident in the New Worldmicrohylids that comprise two clades, Gastrophryninae and Otophryninae. To facilitate comparisons among these clades, we describe the larval chondrocranium, skeletal development, and adult osteology of Gastrophryne carolinensis. We provide a phylogeneticcontext for these comparisons through a novel phylogenetic analysis of 45 microhylid genera based on data for one mitochondrial and three nuclear loci from previously published studies. Nearly all relationships within the monophyletic Gastrophryninae are resolvedwith robust support. Based on these results, we found that the larval chondrocrania of gastrophrynines share morphological features that distinguish them from Otophryne and other anurans. Among the adults, all gastrophrynines show evidence of an anterior shift ofthe jaws that is correlated with specializations in the otic region, and with the alignment of the planum antorbitale, the cartilage wall separating the nasal capsule from the orbits. The larval infrarostral and the adult mandibles lack a typical anuran mandibular symphysis, and the mentomeckelian bone of the adult is modified with a special process. The most variable part of the skull is the palate in which a neopalatine usually is absent and the vomer may be single or divided. The posteromedial processes of the hyoids of gastrophynines tend to be elaborated, and some taxa bear a peculiar transverse slit in the posterior part of the hyoid corpus. The anterior zonal

When the ball is in the female's court: How the scramble-competition mating system of the North American red squirrel has shaped male physiology and testosterone dynamics.

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Boonstra, Rudy; Dušek, Adam; Lane, Jeffrey E; Boutin, Stan

2017-10-01

Male reproductive success in most mammals is determined by their success in direct inter-male competition through aggression and conflict, resulting in female-defense mating systems being predominant. This is linked to male testosterone levels and its dynamics. However, in certain environments, a scramble-competition mating system has evolved, where female reproductive behavior takes precedence and male testosterone dynamics are unlikely to be related to inter-male competition. We studied the North American red squirrel (Tamiasciurus hudsonicus), a species with a well-established scramble-competition system. Using an ACTH hormonal challenge protocol as a proxy for competitive interactions, we compared the testosterone dynamics in breeding males in late winter with that in nonbreeding males in late spring in the Yukon. To gain an integrated picture of their physiological state, we also assessed changes in their stress response, body mass, energy mobilization, and indices of immune function. Testosterone levels at the base bleed were high in breeding males (2.72ng/mL) and virtually absent in non-breeding males (0.04ng/mL). Breeding males were in better condition (heavier body mass, higher hematocrit, and higher erythrocytes), had higher indices of immune function (neutrophil:lymphocyte ratio), but a similar ability to mobilize energy (glucose) compared with non-breeding males. Though total cortisol was higher in non-breeding males, free cortisol was twice as high in breeding males as their corticosteroid binding globulin levels were half as high. In response to the ACTH challenge, testosterone levels in breeding males declined 49% over the first hour and increased 36% over the next hour; in non-breeding males levels showed no change. Free cortisol increased only modestly (26% in breeding males; 23% in non-breeding males). Glucose levels changed similarly in breeding and nonbreeding males, declining for the first 30min and then increasing for the next 60min. Thus

Stator and Rotor Faults Diagnosis of Squirrel Cage Motor Based on Fundamental Component Extraction Method

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Guoqing An

2017-01-01

Full Text Available Nowadays, stator current analysis used for detecting the incipient fault in squirrel cage motor has received much attention. However, in the case of interturn short circuit in stator, the traditional symmetrical component method has lost the precondition due to the harmonics and noise; the negative sequence component (NSC is hard to be obtained accurately. For broken rotor bars, the new added fault feature blanked by fundamental component is also difficult to be discriminated in the current spectrum. To solve the above problems, a fundamental component extraction (FCE method is proposed in this paper. On one hand, via the antisynchronous speed coordinate (ASC transformation, NSC of extracted signals is transformed into the DC value. The amplitude of synthetic vector of NSC is used to evaluate the severity of stator fault. On the other hand, the extracted fundamental component can be filtered out to make the rotor fault feature emerge from the stator current spectrum. Experiment results indicate that this method is feasible and effective in both interturn short circuit and broken rotor bars fault diagnosis. Furthermore, only stator currents and voltage frequency are needed to be recorded, and this method is easy to implement.

Demography of a population collapse: the Northern Idaho ground squirrel (Spermophilus brunneus brunneus)

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Sherman, P.W.; Runge, M.C.

2002-01-01

We studied the demography of a population of Northern Idaho ground squirrels (Spermophilus brunneus brunneus) in Adams Co., Idaho. The population was completely censused yearly from 1987 to 1999, during which time it declined from 272 to 10 animals. The finite population growth rate, based on a Leslie matrix model of average life-history parameters, was only 0.72 (i.e., significantly conifers to encroach on inhabited meadows, shrinking them and closing dispersal routes. The proximate cause of the population's collapse was mortality of older breeding females, which reduced the mean age of breeders. Younger females had lower average pregnancy rates and litter sizes. To place our results in context we developed a new, general classification of anthropogenic population declines, based on whether they are caused by changes in the means of the life-history parameters (blatant disturbances), their variances (inappropriate variations), or the correlations among them (evolutionary traps). Many S. b. brunneus populations have disappeared in recent years, apparently due to blatant disturbances, especially loss of habitat and changes in food-plant composition, resulting in inadequate prehibernation nutrition and starvation overwinter. In addition, our study population may have been caught in an evolutionary trap, because the vegetational cues that could potentially enable the animals to adjust reproduction to the anticipated food supply no longer correlate with availability of fat-laden seeds.

Radiosensitivity of ileum crypt cells in hibernating, arousing, and awake ground squirrels (Citellus tridecemlineatus)

International Nuclear Information System (INIS)

Jaroslow, B.N.; Michael Fry, R.J.; Suhrbier, K.M.; Sallese, A.R.

1976-01-01

Radiosensitivity of ileal crypt cells, to 60 Co gamma radiation, was studied in ground squirrels (Citellus tridecemlineatus) during hibernation, arousal, and the euthermic state. Survival of ileal crypt cells, assayed by the microcolony technique from stained transverse sections of ileum, was greater in animals irradiated in hibernation or 1 hr after initiation of arousal from hibernation. Crypt survival returned to the level of irradiated nonhibernating controls in animals irradiated 3 to 7 hr after initiation of arousal. Over the exposure range of 1500 to 2400 R, the survival of crypt cells for euthermic controls gave a D 0 = 133 +- 12 R and for animals irradiated in hibernation it gave a D 0 = 487 +- 92 R. In animals irradiated 1 hr after initiation of arousal, when core temperature is within the range of euthermic controls, crypt survival was almost as high as in the hibernators. These results suggest that the increased resistance of ileal crypt cells in hibernating animals could be due to hypoxia, although not direct evidence for hypoxia in hibernation was established. The changes in mitotic index of ileal crypt cells during hibernation and arousal indicate an alteration in the distribution of cells in the phases of the cycle. This change in distribution may also have contributed to the increased radioresistance of hibernators

Early and late changes in the distal forelimb representation of the supplementary motor area after injury to frontal motor areas in the squirrel monkey.

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Eisner-Janowicz, Ines; Barbay, Scott; Hoover, Erica; Stowe, Ann M; Frost, Shawn B; Plautz, Erik J; Nudo, Randolph J

2008-09-01

Neuroimaging studies in stroke survivors have suggested that adaptive plasticity occurs following stroke. However, the complex temporal dynamics of neural reorganization after injury make the interpretation of functional imaging studies equivocal. In the present study in adult squirrel monkeys, intracortical microstimulation (ICMS) techniques were used to monitor changes in representational maps of the distal forelimb in the supplementary motor area (SMA) after a unilateral ischemic infarct of primary motor (M1) and premotor distal forelimb representations (DFLs). In each animal, ICMS maps were derived at early (3 wk) and late (13 wk) postinfarct stages. Lesions resulted in severe deficits in motor abilities on a reach and retrieval task. Limited behavioral recovery occurred and plateaued at 3 wk postinfarct. At both early and late postinfarct stages, distal forelimb movements could still be evoked by ICMS in SMA at low current levels. However, the size of the SMA DFL changed after the infarct. In particular, wrist-forearm representations enlarged significantly between early and late stages, attaining a size substantially larger than the preinfarct area. At the late postinfarct stage, the expansion in the SMA DFL area was directly proportional to the absolute size of the lesion. The motor performance scores were positively correlated to the absolute size of the SMA DFL at the late postinfarct stage. Together, these data suggest that, at least in squirrel monkeys, descending output from M1 and dorsal and ventral premotor cortices is not necessary for SMA representations to be maintained and that SMA motor output maps undergo delayed increases in representational area after damage to other motor areas. Finally, the role of SMA in recovery of function after such lesions remains unclear because behavioral recovery appears to precede neurophysiological map changes.

Two models of the sound-signal frequency dependence on the animal body size as exemplified by the ground squirrels of Eurasia (mammalia, rodentia).

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Nikol'skii, A A

2017-11-01

Dependence of the sound-signal frequency on the animal body length was studied in 14 ground squirrel species (genus Spermophilus) of Eurasia. Regression analysis of the total sample yielded a low determination coefficient (R 2 = 26%), because the total sample proved to be heterogeneous in terms of signal frequency within the dimension classes of animals. When the total sample was divided into two groups according to signal frequency, two statistically significant models (regression equations) were obtained in which signal frequency depended on the body size at high determination coefficients (R 2 = 73 and 94% versus 26% for the total sample). Thus, the problem of correlation between animal body size and the frequency of their vocal signals does not have a unique solution.

Environmental Impact Statement Addressing Campus Development at Fort George Meade, Maryland

Science.gov (United States)

2010-09-01

Dumetella carolinensis), mockingbird (Mimus polyglyottos), Carolina chickadee (Poecile carolinensis), Carolina wren (Thryothorus ludovicianus), house wren...regulations, the MBTA makes it unlawful to pursue, hunt, take, capture, or kill ; attempt to take, capture or kill ; possess, offer to sell, barter...foreign country, any bird, part, nest, or egg that was captured, killed , taken, shipped, transported, or carried contrary to the laws from where it was

Mamíferos silvestres de la Reserva Ecológica del Pedregal de San Ángel en Ciudad Universitaria, Universidad Nacional Autónoma de México, México, D. F. Wild mammals of Reserva Ecológica del Pedregal de San Ángel, Ciudad Universitaria, UNAM, Mexico, D.F.

Directory of Open Access Journals (Sweden)

Yolanda Hortelano-Moncada

2009-08-01

Full Text Available Se realizó un inventario de las especies de mamíferos que habitan en la Reserva Ecológica del Pedregal de San Ángel (REPSA. Los datos se obtuvieron a partir de registros de colecciones científicas, de recolectas recientes en el área y de consultas en literatura especializada. Los resultados comprenden 628 registros acumulados desde 1943 y corresponden a 33 especies, agrupadas en 28 géneros, 15 familias y 6 órdenes de mamíferos. La ardilla gris (Sciurus aureogaster nigrescens y el ratón del altiplano (Peromyscus melanophrys melanophrys se registran por primera vez para la REPSA; asimismo, existen 2 registros que están publicados pero no listados en los inventarios previos a la reserva, el murciélago colorado, Lasiurus blossevillii teliotis, y el cuinique, Spermophilus adocetus adocetus; en las categorías de riesgo se encuentran como amenazadas 2 especies y 1 en la de protección especial, y hay 7 endémicas de México. La Reserva es uno de los últimos reductos de material genético de especies cuya localidad tipo se encuentra en la cuenca de México. El componente mastofaunístico de la zona es importante para el mantenimiento de la biodiversidad, por lo que el estudio y la protección de este ecosistema al interior de la ciudad de México debe continuarse.This paper documents the mammals from the Reserva Ecológica del Pedregal de San Ángel. Data were gathered from records in mammal collections, the specialized literature, and through collecting efforts in the area. Records spanning 1943 to the present document the presence of 33 species, 28 genera, 15 families, and 6 orders of mammals. One squirrel and one mouse (Sciurus aureogaster nigrescens, and Peromyscus m. melanophrys are reported for the first time for the reserve. Two addtional records have been previously published but have not been included in previous inventories for the reserve: the red bat, Lasiurus blossevillii teliotis and the cuinique, Spermophilus adocetus

Multilevel landscape utilization of the Siberian flying squirrel: Scale effects on species habitat use.

Science.gov (United States)

Remm, Jaanus; Hanski, Ilpo K; Tuominen, Sakari; Selonen, Vesa

2017-10-01

Animals use and select habitat at multiple hierarchical levels and at different spatial scales within each level. Still, there is little knowledge on the scale effects at different spatial levels of species occupancy patterns. The objective of this study was to examine nonlinear effects and optimal-scale landscape characteristics that affect occupancy of the Siberian flying squirrel, Pteromys volans , in South- and Mid-Finland. We used presence-absence data ( n  = 10,032 plots of 9 ha) and novel approach to separate the effects on site-, landscape-, and regional-level occupancy patterns. Our main results were: landscape variables predicted the placement of population patches at least twice as well as they predicted the occupancy of particular sites; the clear optimal value of preferred habitat cover for species landscape-level abundance is a surprisingly low value (10% within a 4 km buffer); landscape metrics exert different effects on species occupancy and abundance in high versus low population density regions of our study area. We conclude that knowledge of regional variation in landscape utilization will be essential for successful conservation of the species. The results also support the view that large-scale landscape variables have high predictive power in explaining species abundance. Our study demonstrates the complex response of species occurrence at different levels of population configuration on landscape structure. The study also highlights the need for data in large spatial scale to increase the precision of biodiversity mapping and prediction of future trends.

Effects of prenatal 60Co irradiation on postnatal neural, learning, and hormonal development of the squirrel monkey

International Nuclear Information System (INIS)

Ordy, J.M.; Brizzee, K.R.; Dunlap, W.P.; Knight, C.

1982-01-01

The goals of this study were to examine the effects of 0, 50, and 100 rad of 60 Co administered prenatally on postnatal development of neuromuscular coordination, visual discrimination learning, spontaneous light-dark stabilimeter activity, plasma cortisol, and somatometric growth rates of diurnal squirrel monkeys from birth to 90 days. In terms of accuracy, completeness, and time required for performance of reflexes and neuromuscular coordination, the performance of 50- and 100-rad offspring was less accurate and poorly coordinated and required more time for completion to that of controls. In visual orientation, discrimination, and reversal learning, the percentage correct responses of the 50- and 100-rad offspring were significantly lower than those of controls. Spontaneous light-dark stabilimeter activity of 50- and 100-rad offspring was significantly higher in the dark session than that of controls. Plasma cortisol was significantly higher in 100-rad infants than in controls. Comparisons of somatometric growth rates indicated that postnatal head circumference, crown-rump length, and to a lesser extent body weight increased at significantly slower rates in 50- and 100-rad offspring. These findings should provide essential information for formulating and carrying out multivariate behavioral, biochemical, and morphometric assessments of low-dose effects on the brain of primate offspring within demonstrable dose-response curves

Reduced-Capacity Inrush Current Suppressor Using a Matrix Converter in a Wind Power Generation System with Squirrel-Cage Induction Machines

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Sho Shibata

2016-03-01

Full Text Available This paper describes the reduced capacity of the inrush current suppressor using a matrix converter (MC in a large-capacity wind power generation system (WPGS with two squirrel-cage induction machines (SCIMs. These SCIMs are switched over depending on the wind speed. The input side of the MC is connected to the source in parallel. The output side of the MC is connected in series with the SCIM through matching transformers. The modulation method of the MC used is direct duty ratio pulse width modulation. The reference output voltage of the MC is decided by multiplying the SCIM current with the variable control gain. Therefore, the MC performs as resistors for the inrush current. Digital computer simulation is implemented to confirm the validity and practicability of the proposed inrush current suppressor using PSCAD/EMTDC (power system computer-aided design/electromagnetic transients including DC. Furthermore, the equivalent resistance of the MC is decided by the relationship between the equivalent resistance and the capacity of the MC. Simulation results demonstrate that the proposed inrush current suppressor can suppress the inrush current perfectly.

Metabolism of (125I)tyramine cellobiose-labeled low density lipoproteins in squirrel monkeys

International Nuclear Information System (INIS)

Portman, O.W.; Alexander, Manfred

1985-01-01

Low density lipoproteins labeled with ( 125 I)tyramine cellobiose (( 125 I)TC-LDL) were removed from the circulation of squirrel monkeys at a similar but slightly slower rate than LDLs labeled with 125 I, ( 125 I)hydroxypenyl propionic acid, or ( 3 H)leucine. After the simultaneous injection of (( 125 I)TC-LDL) and ( 131 I)LDL labeled with 131 ICI, the 125 I was also removed at a slightly slower rate than 131 I. Most of the radioactivity was retained in tissues and not excreted during the 24 h after injection of ( 125 I)TC-LDL. This finding supports the claim of Pittman et al. (18) that ( 125 I)TC-LDL can be used to determine the irreversible uptake of LDL by different tissues. The liver cleared more LDL than any other organ, but the adrenals and ovaries were more active per gram. Trichloroacetic acid (TCA) precipitated more than 80% of the radioactivity in the tissues that had low 125 I uptake, but only about 50% of the 125 I in more active tissues (liver, adrenals, ovaries and spleen). Only a small percentage of 125 I in urine and bile was TCA-precipitable. In the dual label experiment with ( 125 I)TC-LDL and ( 131 I)LDL there was a selective retention of 125 I in samples from liver, spleen, adrenals, and perhaps testes, and an almost complete selectivity for 125 I in bile and feces. The aortic intima plus inner media (AIM) cleared much less LDL than other tissues, but the uptake by the entire AIM was proportional to the cholesterol concentration and weight of the total AIM. There was, however, no correlation between either of the latter two measurements and the uptake of LDL per pram of AIM. (author)

Integrating archaeology and ancient DNA analysis to address invasive species colonization in the Gulf of Alaska.

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West, Catherine; Hofman, Courtney A; Ebbert, Steve; Martin, John; Shirazi, Sabrina; Dunning, Samantha; Maldonado, Jesus E

2017-10-01

The intentional and unintentional movement of plants and animals by humans has transformed ecosystems and landscapes globally. Assessing when and how a species was introduced are central to managing these transformed landscapes, particularly in island environments. In the Gulf of Alaska, there is considerable interest in the history of mammal introductions and rehabilitating Gulf of Alaska island environments by eradicating mammals classified as invasive species. The Arctic ground squirrel (Urocitellus parryii) is of concern because it affects vegetation and seabirds on Gulf of Alaska islands. This animal is assumed to have been introduced by historic settlers; however, ground squirrel remains in the prehistoric archaeological record of Chirikof Island, Alaska, challenge this timeline and suggest they colonized the islands long ago. We used 3 lines of evidence to address this problem: direct radiocarbon dating of archaeological squirrel remains; evidence of prehistoric human use of squirrels; and ancient DNA analysis of dated squirrel remains. Chirikof squirrels dated to at least 2000 years ago, and cut marks on squirrel bones suggested prehistoric use by people. Ancient squirrels also shared a mitochondrial haplotype with modern Chirikof squirrels. These results suggest that squirrels have been on Chirikof longer than previously assumed and that the current population of squirrels is closely related to the ancient population. Thus, it appears ground squirrels are not a recent, human-mediated introduction and may have colonized the island via a natural dispersal event or an ancient human translocation. © 2016 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

Post-weaning parental care increases fitness but is not heritable in North American red squirrels.

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Lane, J E; McAdam, A G; Charmantier, A; Humphries, M M; Coltman, D W; Fletcher, Q; Gorrell, J C; Boutin, S

2015-06-01

Most empirical attempts to explain the evolution of parental care have focused on its costs and benefits (i.e. fitness consequences). In contrast, few investigations have been made of the other necessary prerequisite for evolutionary change, inheritance. Here, we examine the fitness consequences and heritability (h(2)) of a post-weaning parental care behaviour (territory bequeathal) in a wild population of North American red squirrels. Each year, a subset (average across all years = 19%) of reproductive females bequeathed their territory to a dependent offspring. Bequeathing females experienced higher annual reproductive success and did not suffer a survival cost to themselves relative to those females retaining their territory. Bequeathing females thus realized higher relative annual fitness [ω = 1.18 ± 0.03 (SE)] than nonbequeathing females [ω = 0.96 ± 0.02 (SE)]. Additive genetic influences on bequeathal behaviour, however, were not significantly different from 0 (h(2) = 1.9 × 10(-3); 95% highest posterior density interval = 3.04 × 10(-8) to 0.37) and, in fact, bequeathal behaviour was not significantly repeatable (R = 2.0 × 10(-3); 95% HPD interval = 0-0.27). In contrast, directional environmental influences were apparent. Females were more likely to bequeath in years following low food abundance and when food availability in the upcoming autumn was high. Despite an evident fitness benefit, a lack of heritable genetic variance will constrain evolution of this trait. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

A contribution to the study of the thermal behavior and of the electric performance of squirrel-cage induction motors; Uma contribuicao ao estudo do comportamento termico e do desempenho eletrico de motores de inducao com rotor em gaiola

Energy Technology Data Exchange (ETDEWEB)

Avolio, Edwin

1992-03-01

A thermal-electric mathematical model for a squirrel cage induction motors which permits to specify the best motor for specific drive, under thermal and electric aspects based, only on manufacturer technical bulletins and technical information is presented. Changes of rotor parameters due Skin Effect and changes of winding resistances (both stator and rotor) with the temperature are considered. The accuracy of this model is appraised using experimental results. The thermal behavior and electric performance for some motors are obtained for continuos and intermittent duties with sinusoidal and non-sinusoidal voltages. (author)

Number-related discrimination and summation by squirrel monkeys (Saimiri sciureus sciureus and S. boliviensus boliviensus) on the basis of the number of sides of polygons.

Science.gov (United States)

Terrell, D F; Thomas, R K

1990-09-01

In Experiment 1, with the number of sides or angles of irregular polygons as cues, programmed training, and a 90% correct criterion (36 of 40), 2 squirrel monkeys' (Saimiri sciureus sciureus and S. boliviensus boliviensus) best performances were to discriminate heptagons from octagons, a 3rd's best was hexagons from heptagons, and a 4th's best was pentagons from heptagons. In Experiment 2, on most trials 2 polygons on one or both discriminanda had to be summed to determine which discrimination had the total fewer sides. Only 1 monkey met criterion (27 of 30) on the 2 tasks, 6 vs. 8 and 7 vs. 8 sides, but the other 3 performed better than chance on the 6 vs. 8 task. We conclude that previous studies of animals' discrimination of polygons in terms of complexity were minimally relevant to this work, and counting and subitizing were rejected in favor of a prototype-matching process to explain our monkeys' performances.

Differential growth of Mycobacterium leprae strains (SNP genotypes) in armadillos.

Science.gov (United States)

Sharma, Rahul; Singh, Pushpendra; Pena, Maria; Subramanian, Ramesh; Chouljenko, Vladmir; Kim, Joohyun; Kim, Nayong; Caskey, John; Baudena, Marie A; Adams, Linda B; Truman, Richard W

2018-04-14

Leprosy (Hansen's Disease) has occurred throughout human history, and persists today at a low prevalence in most populations. Caused by Mycobacterium leprae, the infection primarily involves the skin, mucosa and peripheral nerves. The susceptible host range for Mycobacterium leprae is quite narrow. Besides humans, nine banded armadillos (Dasypus novemcinctus) and red squirrels (Sciurus vulgaris) are the only other natural hosts for M. leprae, but only armadillos recapitulate the disease as seen in humans. Armadillos across the Southern United States harbor a single predominant genotypic strain (SNP Type-3I) of M. leprae, which is also implicated in the zoonotic transmission of leprosy. We investigated, whether the zoonotic strain (3I) has any notable growth advantages in armadillos over another genetically distant strain-type (SNP Type-4P) of M. leprae, and if M. leprae strains manifest any notably different pathology among armadillos. We co-infected armadillos (n = 6) with 2 × 10 9 highly viable M. leprae of both strains and assessed the relative growth and dissemination of each strain in the animals. We also analyzed 12 additional armadillos, 6 each individually infected with the same quantity of either strain. The infections were allowed to fulminate and the clinical manifestations of the disease were noted. Animals were humanely sacrificed at the terminal stage of infection and the number of bacilli per gram of liver, spleen and lymph node tissue were enumerated by Q-PCR assay. The growth of M. leprae strain 4P was significantly higher (P leprae strains within armadillos suggest there are notable pathological variations between M. leprae strain-types. Copyright © 2018. Published by Elsevier B.V.

Impacts of late Quaternary environmental change on the long-tailed ground squirrel (Urocitellus undulatus) in Mongolia.

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McLean, Bryan S; Nyamsuren, Batsaikhan; Tchabovsky, Andrey; Cook, Joseph A

2018-03-08

Impacts of Quaternary environmental changes on mammal faunas of central Asia remain poorly understood due to a lack of geographically comprehensive phylogeographic sampling for most species. To help address this knowledge gap, we conducted the most extensive molecular analysis to date of the long-tailed ground squirrel (Urocitellus undulatus Pallas 1778) in Mongolia, a country that comprises the southern core of this species' range. Drawing on material from recent collaborative field expeditions, we genotyped 128 individuals at 2 mitochondrial genes (cytochrome b and cytochrome oxidase I; 1 797 bp total). Phylogenetic inference supports the existence of two deeply divergent infraspecific lineages (corresponding to subspecies U. u. undulatus and U. u. eversmanni), a result in agreement with previous molecular investigations but discordant with patterns of range-wide craniometric and external phenotypic variation. In the widespread western eversmanni lineage, we recovered geographically-associated clades from the: (a) Khangai, (b) Mongolian Altai, and (c) Govi Altai mountain ranges. Phylogeographic structure in U. u. eversmanni is consistent with an isolation-by-distance model; however, genetic distances are significantly lower than among subspecies, and intra-clade relationships are largely unresolved. The latter patterns, as well as the relatively higher nucleotide polymorphism of populations from the Great Lakes Depression of northwestern Mongolia, suggest a history of range shifts into these lowland areas in response to Pleistocene glaciation and environmental change, followed by upslope movements and mitochondrial lineage sorting with Holocene aridification. Our study illuminates possible historical mechanisms responsible for U. undulatus genetic structure and contributes to a framework for ongoing exploration of mammalian response to past and present climate change in central Asia.

Biochemical adaptations of mammalian hibernation: exploring squirrels as a perspective model for naturally induced reversible insulin resistance

Energy Technology Data Exchange (ETDEWEB)

Wu, C-W.; Biggar, K.K.; Storey, K.B. [Carleton University, Department of Biology, Institute of Biochemistry, Ottawa, ON (Canada)

2013-01-28

An important disease among human metabolic disorders is type 2 diabetes mellitus. This disorder involves multiple physiological defects that result from high blood glucose content and eventually lead to the onset of insulin resistance. The combination of insulin resistance, increased glucose production, and decreased insulin secretion creates a diabetic metabolic environment that leads to a lifetime of management. Appropriate models are critical for the success of research. As such, a unique model providing insight into the mechanisms of reversible insulin resistance is mammalian hibernation. Hibernators, such as ground squirrels and bats, are excellent examples of animals exhibiting reversible insulin resistance, for which a rapid increase in body weight is required prior to entry into dormancy. Hibernator studies have shown differential regulation of specific molecular pathways involved in reversible resistance to insulin. The present review focuses on this growing area of research and the molecular mechanisms that regulate glucose homeostasis, and explores the roles of the Akt signaling pathway during hibernation. Here, we propose a link between hibernation, a well-documented response to periods of environmental stress, and reversible insulin resistance, potentially facilitated by key alterations in the Akt signaling network, PPAR-γ/PGC-1α regulation, and non-coding RNA expression. Coincidentally, many of the same pathways are frequently found to be dysregulated during insulin resistance in human type 2 diabetes. Hence, the molecular networks that may regulate reversible insulin resistance in hibernating mammals represent a novel approach by providing insight into medical treatment of insulin resistance in humans.

Biochemical adaptations of mammalian hibernation: exploring squirrels as a perspective model for naturally induced reversible insulin resistance

International Nuclear Information System (INIS)

Wu, C-W.; Biggar, K.K.; Storey, K.B.

2013-01-01

An important disease among human metabolic disorders is type 2 diabetes mellitus. This disorder involves multiple physiological defects that result from high blood glucose content and eventually lead to the onset of insulin resistance. The combination of insulin resistance, increased glucose production, and decreased insulin secretion creates a diabetic metabolic environment that leads to a lifetime of management. Appropriate models are critical for the success of research. As such, a unique model providing insight into the mechanisms of reversible insulin resistance is mammalian hibernation. Hibernators, such as ground squirrels and bats, are excellent examples of animals exhibiting reversible insulin resistance, for which a rapid increase in body weight is required prior to entry into dormancy. Hibernator studies have shown differential regulation of specific molecular pathways involved in reversible resistance to insulin. The present review focuses on this growing area of research and the molecular mechanisms that regulate glucose homeostasis, and explores the roles of the Akt signaling pathway during hibernation. Here, we propose a link between hibernation, a well-documented response to periods of environmental stress, and reversible insulin resistance, potentially facilitated by key alterations in the Akt signaling network, PPAR-γ/PGC-1α regulation, and non-coding RNA expression. Coincidentally, many of the same pathways are frequently found to be dysregulated during insulin resistance in human type 2 diabetes. Hence, the molecular networks that may regulate reversible insulin resistance in hibernating mammals represent a novel approach by providing insight into medical treatment of insulin resistance in humans

Metabolic changes associated with the long winter fast dominate the liver proteome in 13-lined ground squirrels

Science.gov (United States)

Hindle, Allyson G.; Grabek, Katharine R.; Epperson, L. Elaine; Karimpour-Fard, Anis

2014-01-01

Small-bodied hibernators partition the year between active homeothermy and hibernating heterothermy accompanied by fasting. To define molecular events underlying hibernation that are both dependent and independent of fasting, we analyzed the liver proteome among two active and four hibernation states in 13-lined ground squirrels. We also examined fall animals transitioning between fed homeothermy and fasting heterothermy. Significantly enriched pathways differing between activity and hibernation were biased toward metabolic enzymes, concordant with the fuel shifts accompanying fasting physiology. Although metabolic reprogramming to support fasting dominated these data, arousing (rewarming) animals had the most distinct proteome among the hibernation states. Instead of a dominant metabolic enzyme signature, torpor-arousal cycles featured differences in plasma proteins and intracellular membrane traffic and its regulation. Phosphorylated NSFL1C, a membrane regulator, exhibited this torpor-arousal cycle pattern; its role in autophagosome formation may promote utilization of local substrates upon metabolic reactivation in arousal. Fall animals transitioning to hibernation lagged in their proteomic adjustment, indicating that the liver is more responsive than preparatory to the metabolic reprogramming of hibernation. Specifically, torpor use had little impact on the fall liver proteome, consistent with a dominant role of nutritional status. In contrast to our prediction of reprogramming the transition between activity and hibernation by gene expression and then within-hibernation transitions by posttranslational modification (PTM), we found extremely limited evidence of reversible PTMs within torpor-arousal cycles. Rather, acetylation contributed to seasonal differences, being highest in winter (specifically in torpor), consistent with fasting physiology and decreased abundance of the mitochondrial deacetylase, SIRT3. PMID:24642758

Replicated population divergence caused by localized coevolution? A test of three hypotheses in the red crossbill-lodgepole pine system.

Science.gov (United States)

Edelaar, P; Benkman, C W

2006-09-01

Several lines of evidence support the hypothesis that local populations of red crossbills (Loxia curvirostra complex) enter into a predator-prey arms race with lodgepole pine (Pinus contorta latifolia) in the absence of competing pine squirrels (Tamiasciurus hudsonicus). Nevertheless, the alternative hypotheses that neutral evolution or factors other than squirrels have caused crossbill population differentiation have not been thoroughly tested. We compared crossbill and pine cone morphology between island populations where squirrels are absent or present, and mainland sites where squirrels are present, in order to distinguish among these hypotheses. All comparisons supported an effect of squirrel absence, not island status, on crossbill and cone morphology. Hence our results provide further evidence that strong localized coevolutionary interactions in a geographic mosaic have driven adaptive population differentiation. In addition, vocal differentiation of crossbills was related to the absence of squirrels, but not to island status. As morphological and vocal differentiation is correlated with reproductive isolation in crossbills, the geographic mosaic of coevolution also seems to promote ecological speciation.

Feeding habits and comparative feeding rates of three southern ...

African Journals Online (AJOL)

Food utilization by three arboreal squirrels was studied with regard to feeding habits and efficiency, food preferences and chemical analyses of the food. Food selected in the field by the two forest subspecies the Ngoye red squirrel Paraxerus palliatus ornatus and the Tonga red squirrel, P. p. tongensis are listed.

Positron emission tomography (PET) imaging of nicotine-induced dopamine release in squirrel monkeys using [18F]Fallypride.

Science.gov (United States)

Naylor, Jennifer E; Hiranita, Takato; Matazel, Katelin S; Zhang, Xuan; Paule, Merle G; Goodwin, Amy K

2017-10-01

Nicotine, the principal psychoactive tobacco constituent, is thought to produce its reinforcing effects via actions within the mesolimbic dopamine (DA) system. The objective of the current study was to examine the effect of nicotine on DA D 2 /D 3 receptor availability in the nonhuman primate brain with the use of the radioligand [ 18 F]fallypride and positron emission tomography (PET). Ten adult male squirrel monkeys were used in the current study. Each subject underwent two PET scans, one with an injection (IV) of saline and subsequently one with an injection of nicotine (0.032mg/kg). The DA D 2 /D 3 antagonist, [ 18 F]fallypride, was delivered IV at the beginning of each scan, and nicotine or saline was delivered at 45min into the scan. Regions of interest (ROI) were drawn on specific brain regions and these were used to quantify standard uptake values (SUVs). The SUV is defined as the average concentration of radioactivity in the ROI x body weight/injected dose. Using the cerebellum as a reference region, SUV ratios (SUV ROI /SUV cerebellum ) were calculated to compare saline and nicotine effects in each ROI. Two-way repeated ANOVA revealed a significant decrease of SUV ratios in both striatal and extrastriatal regions following an injection of nicotine during the PET scans. Like other drugs of abuse, these results indicate that nicotine administration may produce DA release, as suggested by the decrease in [ 18 F]fallypride signal in striatal regions. These findings from a nonhuman primate model provide further evidence that the mesolimbic DA system is affected by the use of products that contain nicotine. Published by Elsevier B.V.

Metabolic changes associated with the long winter fast dominate the liver proteome in 13-lined ground squirrels.

Science.gov (United States)

Hindle, Allyson G; Grabek, Katharine R; Epperson, L Elaine; Karimpour-Fard, Anis; Martin, Sandra L

2014-05-15

Small-bodied hibernators partition the year between active homeothermy and hibernating heterothermy accompanied by fasting. To define molecular events underlying hibernation that are both dependent and independent of fasting, we analyzed the liver proteome among two active and four hibernation states in 13-lined ground squirrels. We also examined fall animals transitioning between fed homeothermy and fasting heterothermy. Significantly enriched pathways differing between activity and hibernation were biased toward metabolic enzymes, concordant with the fuel shifts accompanying fasting physiology. Although metabolic reprogramming to support fasting dominated these data, arousing (rewarming) animals had the most distinct proteome among the hibernation states. Instead of a dominant metabolic enzyme signature, torpor-arousal cycles featured differences in plasma proteins and intracellular membrane traffic and its regulation. Phosphorylated NSFL1C, a membrane regulator, exhibited this torpor-arousal cycle pattern; its role in autophagosome formation may promote utilization of local substrates upon metabolic reactivation in arousal. Fall animals transitioning to hibernation lagged in their proteomic adjustment, indicating that the liver is more responsive than preparatory to the metabolic reprogramming of hibernation. Specifically, torpor use had little impact on the fall liver proteome, consistent with a dominant role of nutritional status. In contrast to our prediction of reprogramming the transition between activity and hibernation by gene expression and then within-hibernation transitions by posttranslational modification (PTM), we found extremely limited evidence of reversible PTMs within torpor-arousal cycles. Rather, acetylation contributed to seasonal differences, being highest in winter (specifically in torpor), consistent with fasting physiology and decreased abundance of the mitochondrial deacetylase, SIRT3. Copyright © 2014 the American Physiological Society.

Effects of drugs of abuse and cholinergic agents on delayed matching-to-sample responding in the squirrel monkey.

Science.gov (United States)

Hudzik, T J; Wenger, G R

1993-04-01

To study how drugs may disrupt short-term memory function, squirrel monkeys were trained to respond under a titrating delayed matching-to-sample schedule of reinforcement. Monkeys could respond on each of three keys in an operant chamber. At the start of each trial, the 30th response on the center key illuminated each of the side keys, one of which matched the stimulus presented on the center key (simultaneous matching). A response to the correct (matching) side key turned off all stimuli and initiated a delay, the length of which varied as a function of ongoing performance. After the delay, stimuli were randomly presented on two of the three keys. A response to the key which matched the color on the center key before the delay resulted in delivery of a food pellet (delayed matching). Incorrect simultaneous or delayed matching responses initiated a timeout. Under this procedure, diazepam and scopolamine decreased delayed matching accuracy at one or more doses that did not significantly decrease mean delay values, but only scopolamine decreased matching accuracy at a dose that did not significantly decrease response rates. Cocaine decreased mean delay values after the highest dose without affecting matching accuracy. Pentobarbital and methylscopolamine decreased matching accuracy and mean and maximum delay values after the highest doses. Nicotine and phencyclidine produced small decreases in delayed matching accuracy without affecting mean and maximum delay values. Caffeine, morphine, physostigmine and neostigmine did not alter matching performance even after doses that markedly decreased rates of responding.(ABSTRACT TRUNCATED AT 250 WORDS)

(RODENTIA: SCIURIDAE).

African Journals Online (AJOL)

DOBRORUKA, L J 1970. Behaviour in the bush squirrel, Paraxerus cepapi (A Smith, 1836). Revue Zoo I. Bot. afro 82: 131-141. GUNTER, G cl ELEUTERIUS, L 1971. Bark-eating by the common gray squirrel following a hurricane. Am. Midi. Nat. 85:23S. NIXON, C M 1970. Insects as food for juvenile gray squirrels. Am. Midi.

I materiali della collezione Altobello del Museo di Zoologia dell'Università di Bologna 1. Mammiferi

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Dino Scaravelli

1994-05-01

Full Text Available Abstract Materials of Altobello collection in the Zoological Museum, University of Bologna 1. Mammals - Mammals of Altobello Collection of the Zoologica1 Museum, University of Bologna, are listed. 165 stuffed specimens of 26 species are now present, coming from Central Italy (years 1889 - 1929. Only a specimens of Sciurus vulgaris coming from Tuscany is not comprised in the "Catalogo manoscritto della fauna dell'Abruzzo e del Molise" of the Author. Riassunto Sono passati in rassegna i Mammiferi della Collezione Altobello presenti nel Museo di Zoologia dell'Università di Bologna. 165 esemplari naturalizzati appartenenti a 26 specie e provenienti dal centro Italia (anni 1889 - 1929 sono attualmente presenti. Solo un esemplare di Sciurus vulgaris proveniente dalla Toscana non fa parte del "Catalogo manoscritto della fauna dell'Abruzzo e del Molise" dell'Autore.

Functional Characteristics of the Flying Squirrel's Cecal Microbiota under a Leaf-Based Diet, Based on Multiple Meta-Omic Profiling

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Hsiao-Pei Lu

2018-01-01

Full Text Available Mammalian herbivores rely on microbial activities in an expanded gut chamber to convert plant biomass into absorbable nutrients. Distinct from ruminants, small herbivores typically have a simple stomach but an enlarged cecum to harbor symbiotic microbes; however, knowledge of this specialized gut structure and characteristics of its microbial contents is limited. Here, we used leaf-eating flying squirrels as a model to explore functional characteristics of the cecal microbiota adapted to a high-fiber, toxin-rich diet. Specifically, environmental conditions across gut regions were evaluated by measuring mass, pH, feed particle size, and metabolomes. Then, parallel metagenomes and metatranscriptomes were used to detect microbial functions corresponding to the cecal environment. Based on metabolomic profiles, >600 phytochemical compounds were detected, although many were present only in the foregut and probably degraded or transformed by gut microbes in the hindgut. Based on metagenomic (DNA and metatranscriptomic (RNA profiles, taxonomic compositions of the cecal microbiota were dominated by bacteria of the Firmicutes taxa; they contained major gene functions related to degradation and fermentation of leaf-derived compounds. Based on functional compositions, genes related to multidrug exporters were rich in microbial genomes, whereas genes involved in nutrient importers were rich in microbial transcriptomes. In addition, genes encoding chemotaxis-associated components and glycoside hydrolases specific for plant beta-glycosidic linkages were abundant in both DNA and RNA. This exploratory study provides findings which may help to form molecular-based hypotheses regarding functional contributions of symbiotic gut microbiota in small herbivores with folivorous dietary habits.

Distribution of wild mammal assemblages along an urban-rural-forest landscape gradient in warm-temperate East Asia.

Science.gov (United States)

Saito, Masayuki; Koike, Fumito

2013-01-01

Urbanization may alter mammal assemblages via habitat loss, food subsidies, and other factors related to human activities. The general distribution patterns of wild mammal assemblages along urban-rural-forest landscape gradients have not been studied, although many studies have focused on a single species or taxon, such as rodents. We quantitatively evaluated the effects of the urban-rural-forest gradient and spatial scale on the distributions of large and mid-sized mammals in the world's largest metropolitan area in warm-temperate Asia using nonspecific camera-trapping along two linear transects spanning from the urban zone in the Tokyo metropolitan area to surrounding rural and forest landscapes. Many large and mid-sized species generally decreased from forest landscapes to urban cores, although some species preferred anthropogenic landscapes. Sika deer (Cervus nippon), Reeves' muntjac (Muntiacus reevesi), Japanese macaque (Macaca fuscata), Japanese squirrel (Sciurus lis), Japanese marten (Martes melampus), Japanese badger (Meles anakuma), and wild boar (Sus scrofa) generally dominated the mammal assemblage of the forest landscape. Raccoon (Procyon lotor), raccoon dog (Nyctereutes procyonoides), and Japanese hare (Lepus brachyurus) dominated the mammal assemblage in the intermediate zone (i.e., rural and suburban landscape). Cats (feral and free-roaming housecats; Felis catus) were common in the urban assemblage. The key spatial scales for forest species were more than 4000-m radius, indicating that conservation and management plans for these mammal assemblages should be considered on large spatial scales. However, small green spaces will also be important for mammal conservation in the urban landscape, because an indigenous omnivore (raccoon dog) had a smaller key spatial scale (500-m radius) than those of forest mammals. Urbanization was generally the most important factor in the distributions of mammals, and it is necessary to consider the spatial scale of

Distribution of Wild Mammal Assemblages along an Urban–Rural–Forest Landscape Gradient in Warm-Temperate East Asia

Science.gov (United States)

Saito, Masayuki; Koike, Fumito

2013-01-01

Urbanization may alter mammal assemblages via habitat loss, food subsidies, and other factors related to human activities. The general distribution patterns of wild mammal assemblages along urban–rural–forest landscape gradients have not been studied, although many studies have focused on a single species or taxon, such as rodents. We quantitatively evaluated the effects of the urban–rural–forest gradient and spatial scale on the distributions of large and mid-sized mammals in the world's largest metropolitan area in warm-temperate Asia using nonspecific camera-trapping along two linear transects spanning from the urban zone in the Tokyo metropolitan area to surrounding rural and forest landscapes. Many large and mid-sized species generally decreased from forest landscapes to urban cores, although some species preferred anthropogenic landscapes. Sika deer (Cervus nippon), Reeves' muntjac (Muntiacus reevesi), Japanese macaque (Macaca fuscata), Japanese squirrel (Sciurus lis), Japanese marten (Martes melampus), Japanese badger (Meles anakuma), and wild boar (Sus scrofa) generally dominated the mammal assemblage of the forest landscape. Raccoon (Procyon lotor), raccoon dog (Nyctereutes procyonoides), and Japanese hare (Lepus brachyurus) dominated the mammal assemblage in the intermediate zone (i.e., rural and suburban landscape). Cats (feral and free-roaming housecats; Felis catus) were common in the urban assemblage. The key spatial scales for forest species were more than 4000-m radius, indicating that conservation and management plans for these mammal assemblages should be considered on large spatial scales. However, small green spaces will also be important for mammal conservation in the urban landscape, because an indigenous omnivore (raccoon dog) had a smaller key spatial scale (500-m radius) than those of forest mammals. Urbanization was generally the most important factor in the distributions of mammals, and it is necessary to consider the spatial

Distribution of wild mammal assemblages along an urban-rural-forest landscape gradient in warm-temperate East Asia.

Directory of Open Access Journals (Sweden)

Masayuki Saito

Full Text Available Urbanization may alter mammal assemblages via habitat loss, food subsidies, and other factors related to human activities. The general distribution patterns of wild mammal assemblages along urban-rural-forest landscape gradients have not been studied, although many studies have focused on a single species or taxon, such as rodents. We quantitatively evaluated the effects of the urban-rural-forest gradient and spatial scale on the distributions of large and mid-sized mammals in the world's largest metropolitan area in warm-temperate Asia using nonspecific camera-trapping along two linear transects spanning from the urban zone in the Tokyo metropolitan area to surrounding rural and forest landscapes. Many large and mid-sized species generally decreased from forest landscapes to urban cores, although some species preferred anthropogenic landscapes. Sika deer (Cervus nippon, Reeves' muntjac (Muntiacus reevesi, Japanese macaque (Macaca fuscata, Japanese squirrel (Sciurus lis, Japanese marten (Martes melampus, Japanese badger (Meles anakuma, and wild boar (Sus scrofa generally dominated the mammal assemblage of the forest landscape. Raccoon (Procyon lotor, raccoon dog (Nyctereutes procyonoides, and Japanese hare (Lepus brachyurus dominated the mammal assemblage in the intermediate zone (i.e., rural and suburban landscape. Cats (feral and free-roaming housecats; Felis catus were common in the urban assemblage. The key spatial scales for forest species were more than 4000-m radius, indicating that conservation and management plans for these mammal assemblages should be considered on large spatial scales. However, small green spaces will also be important for mammal conservation in the urban landscape, because an indigenous omnivore (raccoon dog had a smaller key spatial scale (500-m radius than those of forest mammals. Urbanization was generally the most important factor in the distributions of mammals, and it is necessary to consider the spatial scale

Attenuating Nicotine Reinforcement and Relapse by Enhancing Endogenous Brain Levels of Kynurenic Acid in Rats and Squirrel Monkeys.

Science.gov (United States)

Secci, Maria E; Auber, Alessia; Panlilio, Leigh V; Redhi, Godfrey H; Thorndike, Eric B; Schindler, Charles W; Schwarcz, Robert; Goldberg, Steven R; Justinova, Zuzana

2017-07-01

The currently available antismoking medications have limited efficacy and often fail to prevent relapse. Thus, there is a pressing need for newer, more effective treatment strategies. Recently, we demonstrated that enhancing endogenous levels of kynurenic acid (KYNA, a neuroinhibitory product of tryptophan metabolism) counteracts the rewarding effects of cannabinoids by acting as a negative allosteric modulator of α7 nicotinic receptors (α7nAChRs). As the effects of KYNA on cannabinoid reward involve nicotinic receptors, in the present study we used rat and squirrel monkey models of reward and relapse to examine the possibility that enhancing KYNA can counteract the effects of nicotine. To assess specificity, we also examined models of cocaine reward and relapse in monkeys. KYNA levels were enhanced by administering the kynurenine 3-monooxygenase (KMO) inhibitor, Ro 61-8048. Treatment with Ro 61-8048 decreased nicotine self-administration in rats and monkeys, but did not affect cocaine self-administration. In rats, Ro 61-8048 reduced the ability of nicotine to induce dopamine release in the nucleus accumbens shell, a brain area believed to underlie nicotine reward. Perhaps most importantly, Ro 61-8048 prevented relapse-like behavior when abstinent rats or monkeys were reexposed to nicotine and/or cues that had previously been associated with nicotine. Ro 61-8048 was also effective in monkey models of cocaine relapse. All of these effects of Ro 61-8048 in monkeys, but not in rats, were reversed by pretreatment with a positive allosteric modulator of α7nAChRs. These findings suggest that KMO inhibition may be a promising new approach for the treatment of nicotine addiction.

Introduction: Chapter 1

Science.gov (United States)

Esque, Todd C.; Nussear, Kenneth E.; Inman, Richard D.; Matocq, Marjorie D.; Weisberg, Peter J.; Dilts, Thomas E.; Leitner, Philip

2013-01-01

The Mohave ground squirrel (Xerospermophilus mohavensis), named just over a century ago (Merriam 1889), is precinctive to the western Mojave Desert in California, USA, and occupies portions of Kern, Los Angeles, Inyo and San Bernardino counties (Best 1995). Early estimates of the geographic range of the squirrel are just 20,000 km2 in area (Hall 1981, Zeiner et al. 1988‐ 1990), one of the smallest distributions among North American ground squirrel species (Hoyt 1972, P. Leitner – pers. obs.). The closest living relative of the Mohave ground squirrel (MGS) is the round‐tailed ground squirrel (Xerospermophilus tereticaudus). Mohave ground squirrels have a “shorter tail with distichous hairs and white undersurface”, but visual differences between the two species are subtle (Hafner and Yates 1983). Speciation likely occurred when portions of the parent population were isolated 4‐1.6 million years ago during the accelerated uplift of the Sierra Nevada, the Transverse Ranges and the Mojave River system, resulting in separation and isolation with MGS evolving in refugia (Hafner 1992, Bell et al. 2009). Subsequently, fluvial‐ lacustrine systems in the Mojave River basin provided vicariance features during the Pleistocene (Hafner 1992, Bell et al. 2009). Responding to previous climate change, the two species potentially migrated into their current ranges from southern refugia after the Last Glacial Maximum, eventually abutting each other along the Mojave River (Hafner and Yates 1983). The species are capable of hybridizing, but intercrosses appear to be rare, and sampling near the zones of potential hybridization remains limited (Bell and Matocq 2011). The only other similar sized squirrel occupying the range of MGS is the white‐tailed antelope ground squirrel (Ammospermophilus leucurus) whose range entirely overlaps MGS, but is easily distinguished by its bright white dorso‐lateral stripes (Best 1995)

Scale-dependent effects of a heterogeneous landscape on genetic differentiation in the Central American squirrel monkey (Saimiri oerstedii.

Directory of Open Access Journals (Sweden)

Mary E Blair

Full Text Available Landscape genetic studies offer a fine-scale understanding of how habitat heterogeneity influences population genetic structure. We examined population genetic structure and conducted a landscape genetic analysis for the endangered Central American Squirrel Monkey (Saimiri oerstedii that lives in the fragmented, human-modified habitats of the Central Pacific region of Costa Rica. We analyzed non-invasively collected fecal samples from 244 individuals from 14 groups for 16 microsatellite markers. We found two geographically separate genetic clusters in the Central Pacific region with evidence of recent gene flow among them. We also found significant differentiation among groups of S. o. citrinellus using pairwise F(ST comparisons. These groups are in fragments of secondary forest separated by unsuitable "matrix" habitats such as cattle pasture, commercial African oil palm plantations, and human residential areas. We used an individual-based landscape genetic approach to measure spatial patterns of genetic variance while taking into account landscape heterogeneity. We found that large, commercial oil palm plantations represent moderate barriers to gene flow between populations, but cattle pastures, rivers, and residential areas do not. However, the influence of oil palm plantations on genetic variance was diminished when we restricted analyses to within population pairs, suggesting that their effect is scale-dependent and manifests during longer dispersal events among populations. We show that when landscape genetic methods are applied rigorously and at the right scale, they are sensitive enough to track population processes even in species with long, overlapping generations such as primates. Thus landscape genetic approaches are extremely valuable for the conservation management of a diverse array of endangered species in heterogeneous, human-modified habitats. Our results also stress the importance of explicitly considering the heterogeneity of

Developing a Topographic Model to Predict the Northern Hardwood Forest Type within Carolina Northern Flying Squirrel (Glaucomys sabrinus coloratus Recovery Areas of the Southern Appalachians

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Andrew Evans

2014-01-01

Full Text Available The northern hardwood forest type is an important habitat component for the endangered Carolina northern flying squirrel (CNFS; Glaucomys sabrinus coloratus for den sites and corridor habitats between boreo-montane conifer patches foraging areas. Our study related terrain data to presence of northern hardwood forest type in the recovery areas of CNFS in the southern Appalachian Mountains of western North Carolina, eastern Tennessee, and southwestern Virginia. We recorded overstory species composition and terrain variables at 338 points, to construct a robust, spatially predictive model. Terrain variables analyzed included elevation, aspect, slope gradient, site curvature, and topographic exposure. We used an information-theoretic approach to assess seven models based on associations noted in existing literature as well as an inclusive global model. Our results indicate that, on a regional scale, elevation, aspect, and topographic exposure index (TEI are significant predictors of the presence of the northern hardwood forest type in the southern Appalachians. Our elevation + TEI model was the best approximating model (the lowest AICc score for predicting northern hardwood forest type correctly classifying approximately 78% of our sample points. We then used these data to create region-wide predictive maps of the distribution of the northern hardwood forest type within CNFS recovery areas.

Impacts of climate change and renewable energy development on habitat of an endemic squirrel, Xerospermophilus mohavensis, in the Mojave Desert, USA

Science.gov (United States)

Inman, Richard D.; Esque, Todd C.; Nussear, Kenneth E.; Leitner, Philip; Matocq, Marjorie D.; Weisberg, Peter J.; Dilts, Thomas E.

2016-01-01

Predicting changes in species distributions under a changing climate is becoming widespread with the use of species distribution models (SDMs). The resulting predictions of future potential habitat can be cast in light of planned land use changes, such as urban expansion and energy development to identify areas with potential conflict. However, SDMs rarely incorporate an understanding of dispersal capacity, and therefore assume unlimited dispersal in potential range shifts under uncertain climate futures. We use SDMs to predict future distributions of the Mojave ground squirrel, Xerospermophilus mohavensis Merriam, and incorporate partial dispersal models informed by field data on juvenile dispersal to assess projected impact of climate change and energy development on future distributions of X. mohavensis. Our models predict loss of extant habitat, but also concurrent gains of new habitat under two scenarios of future climate change. Under the B1 emissions scenario- a storyline describing a convergent world with emphasis on curbing greenhouse gas emissions- our models predicted losses of up to 64% of extant habitat by 2080, while under the increased greenhouse gas emissions of the A2 scenario, we suggest losses of 56%. New potential habitat may become available to X. mohavensis, thereby offsetting as much as 6330 km2 (50%) of the current habitat lost. Habitat lost due to planned energy development was marginal compared to habitat lost from changing climates, but disproportionately affected current habitat. Future areas of overlap in potential habitat between the two climate change scenarios are identified and discussed in context of proposed energy development.

Functional evolution of the feeding system in rodents.

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Philip G Cox

Full Text Available The masticatory musculature of rodents has evolved to enable both gnawing at the incisors and chewing at the molars. In particular, the masseter muscle is highly specialised, having extended anteriorly to originate from the rostrum. All living rodents have achieved this masseteric expansion in one of three ways, known as the sciuromorph, hystricomorph and myomorph conditions. Here, we used finite element analysis (FEA to investigate the biomechanical implications of these three morphologies, in a squirrel, guinea pig and rat. In particular, we wished to determine whether each of the three morphologies is better adapted for either gnawing or chewing. Results show that squirrels are more efficient at muscle-bite force transmission during incisor gnawing than guinea pigs, and that guinea pigs are more efficient at molar chewing than squirrels. This matches the known diet of nuts and seeds that squirrels gnaw, and of grasses that guinea pigs grind down with their molars. Surprisingly, results also indicate that rats are more efficient as well as more versatile feeders than both the squirrel and guinea pig. There seems to be no compromise in biting efficiency to accommodate the wider range of foodstuffs and the more general feeding behaviour adopted by rats. Our results show that the morphology of the skull and masticatory muscles have allowed squirrels to specialise as gnawers and guinea pigs as chewers, but that rats are high-performance generalists, which helps explain their overwhelming success as a group.

Sand Dredging Operations in Lafourche Parish, Near Leeville, Louisiana.

Science.gov (United States)

1982-04-01

hunting was permitted during 1979. However, there are no permits to kill alligators issued for areas below the 10 parts per thousand isohaline line...Northern House Wern Thryothorus ludovicianus Carolina Wren IMimus polyglottos Northern Mockingbird Dumetella carolinensis Cray Catbird Toxostoma rufum

Vestibulo-ocular reflex of the squirrel monkey during eccentric rotation with centripetal acceleration along the naso-occipital axis

Science.gov (United States)

Merfeld, D. M.; Paloski, W. H. (Principal Investigator)

1996-01-01

The vestibulo-ocular reflexes (VOR) are determined not only by angular acceleration, but also by the presence of gravity and linear acceleration. This phenomenon was studied by measuring three-dimensional nystagmic eye movements, with implanted search coils, in four male squirrel monkeys. Monkeys were rotated in the dark at 200 degrees/s, centrally or 79 cm off-axis, with the axis of rotation always aligned with gravity and the spinal axis of the upright monkeys. The monkey's position relative to the centripetal acceleration (facing center or back to center) had a dramatic influence on the VOR. These studies show that a torsional response was always elicited that acted to shift the axis of eye rotation toward alignment with gravito-inertial force. On the other hand, a slow phase downward vertical response usually existed, which shifted the axis of eye rotation away from the gravito-inertial force. These findings were consistent across all monkeys. In another set of tests, the same monkeys were rapidly tilted about their interaural (pitch) axis. Tilt orientations of 45 degrees and 90 degrees were maintained for 1 min. Other than a compensatory angular VOR during the rotation, no consistent eye velocity response was ever observed during or following the tilt. The absence of any response following tilt proves that the observed torsional and vertical responses were not a positional nystagmus. Model simulations qualitatively predict all components of these eccentric rotation and tilt responses. These simulations support the conclusion that the VOR during eccentric rotation may consist of two components: a linear VOR and a rotational VOR. The model predicts a slow phase downward, vertical, linear VOR during eccentric rotation even though there was never a change in the force aligned with monkey's spinal (Z) axis. The model also predicts the torsional components of the response that shift the rotation axis of the angular VOR toward alignment with gravito-inertial force.

Monkeypox

Science.gov (United States)

... been found in many animal species: rope squirrels, tree squirrels, Gambian rats, striped mice, dormice and primates. Doubts persist on the natural history of the virus and further studies are needed to identify the exact reservoir of the monkeypox virus and ...

MONITORING OF THE ENVIRONMENTAL STATE OF THE RIVERS OF THE CHECHEN REPUBLIC

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M. Sh. Saidova

2012-01-01

Full Text Available The ecological status of the river Argun and Squirrel. It is shown that the Argun River and Squirrel are classified as "moderately polluted" water quality class III. The basic measures to protect water resources from pollutants CR.

Do biomass harvesting guidelines influence herpetofauna following harvests of logging residues for renewable energy?.

Science.gov (United States)

Fritts, Sarah; Moorman, Christopher; Grodsky, Steven; Hazel, Dennis; Homyack, Jessica; Farrell, Chris; Castleberry, Steven

2016-04-01

Forests are a major supplier of renewable energy; however, gleaning logging residues for use as woody biomass feedstock could negatively alter habitat for species dependent on downed wood. Biomass Harvesting Guidelines (BHGs) recommend retaining a portion of woody biomass on the forest floor following harvest. Despite BHGs being developed to help ensure ecological sustainability, their contribution to biodiversity has not been evaluated experimentally at operational scales. We compared herpetofauanal evenness, diversity, and richness and abundance of Anaxyrus terrestris and Gastrophryne carolinensis among six treatments that varied in volume and spatial arrangement of woody biomass retained after clearcutting loblolly pine (Pinus taeda) plantations in North Carolina, USA (n = 4), 2011-2014 and Georgia (n = 4), USA 2011-2013. Treatments were: (1) biomass harvest with no BHGs, (2) 15% retention with biomass clustered, (3) 15% retention with biomass dispersed, (4) 30% retention with biomass clustered, (5) 30% retention with biomass dispersed, and (6) no biomass harvest. We captured individuals with drift fence arrays and compared evenness, diversity, and richness metrics among treatments with repeated-measure, linear mixed-effects models. We determined predictors of A. terrestris and G. carolinensis abundances using a priori candidate N-mixture models with woody biomass volume, vegetation structure, and groundcover composition as covariates. We had 206 captures of 25 reptile species and 8710 captures of 17 amphibian species during 53690 trap nights. Herpetofauna diversity, evenness, and richness were similar among treatments. A. terrestris abundance was negatively related to volume of retained woody biomass in treatment units in North Carolina in 2013. G. carolinensis abundance was positively related with volume of retained woody debris in treatment units in Georgia in 2012. Other relationships between A. terrestris and G. carolinensis abundances and habitat metrics

Expression of a wolf spider toxin in tobacco inhibits the growth of microbes and insects

Science.gov (United States)

Abstract Lycotoxin I, from the wolf spider (Lycosa carolinensis), is an amphipathic pore-forming peptide that has antimicrobial and anti-insect activity. Constitutive expression of a lycotoxin I odified for oral toxicity to insects in tobacco (Nicotiana abacum) conferred significantly enhanced resis...

Medium-Sized Mammals around a Radioactive Liquid Waste Lagoon at Los Alamos National Laboratory: Uptake of Contaminants and Evaluation of Radio-Frequency Identification Technology

Energy Technology Data Exchange (ETDEWEB)

Leslie A. Hansen; Phil R. Fresquez; Rhonda J. Robinson; John D. Huchton; Teralene S. Foxx

1999-11-01

Use of a radioactive liquid waste lagoon by medium-sized mammals and levels of tritium, other selected radionuclides, and metals in biological tissues of the animals were documented at Technical Area 53 (TA-53) of Los Alamos National Laboratory during 1997 and 1998. Rock squirrel (Spermophilus variegates), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), and bobcat (Lynx rufus) were captured at TA-53 and at a control site on the Santa Fe National Forest. Captured animals were anesthetized and marked with radio-frequency identification (RFD) tags and/or ear tags. We collected urine and hair samples for tritium and metals (aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, and thallium) analyses, respectively. In addition, muscle and bone samples from two rock squirrels collected from each of TA-53, perimeter, and regional background sites were tested for tritium, {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239,240}Pu, {sup 241}Am, and total uranium. Animals at TA-53 were monitored entering and leaving the lagoon area using a RFID monitor to read identification numbers from the RFID tags of marked animals and a separate camera system to photograph all animals passing through the monitor. Cottontail rabbit (Sylvilagus spp.), rock squirrel, and raccoon were the species most frequently photographed going through the RFID monitor. Less than half of all marked animals in the lagoon area were detected using the lagoon. Male and female rock squirrels from the lagoon area had significantly higher tritium concentrations compared to rock squirrels from the control area. Metals tested were not significantly higher in rock squirrels from TA-53, although there was a trend toward increased levels of lead in some individuals at TA-53. Muscle and bone samples from squirrels in the lagoon area appeared to have higher levels of tritium, total uranium, and {sup 137}Cs than samples collected from perimeter and

Thomas George Lee - Implantation and early development of North American rodents

DEFF Research Database (Denmark)

Carter, Anthony Michael

2011-01-01

A century ago Thomas G. Lee amassed an unparalleled collection of developmental series of North American rodents such as the thirteen-lined ground squirrel, the Plains pocket gopher and Merriam's kangaroo rat. He was the first to describe the initial attachment of the squirrel blastocyst to the a......A century ago Thomas G. Lee amassed an unparalleled collection of developmental series of North American rodents such as the thirteen-lined ground squirrel, the Plains pocket gopher and Merriam's kangaroo rat. He was the first to describe the initial attachment of the squirrel blastocyst...... to the antimesometrial side of the uterus. The full potential of Lee's material was not realized until after his death, when it came into the possession of Mossman. The latter relied heavily on Lee's collection when writing his seminal monograph on the comparative morphogenesis of fetal membranes and much of Lee...

A review of the fern genus Hypolepis (Dennstardtiaceae) in the Malesian and Pacific regions

NARCIS (Netherlands)

Brownsey, P.J.

1987-01-01

Fourteen species and one subspecies of the fern genus Hypolepis Bernh. are recognised in the Malesian and Pacific regions, excluding Australia and New Zealand. Three species, H. hawaiiensis, H. malesiana and H. scabristipes, and one subspecies, H. elegans subsp. carolinensis, are described for the

75 FR 22063 - Endangered and Threatened Wildlife and Plants; 90-day Finding on a Petition to List the Mohave...

Science.gov (United States)

2010-04-27

... squirrel was found to consume leaves of annual and perennial plants, their fruits and seeds, fungi, and... mechanisms; or (e) Other natural or manmade factors affecting its continued existence. (4) Information on... affect the conservation of the Mohave ground squirrel. (6) Information on the population status of...

Energy regulation in context: Free-living female arctic ground squirrels modulate the relationship between thyroid hormones and activity among life history stages.

Science.gov (United States)

Wilsterman, Kathryn; Buck, C Loren; Barnes, Brian M; Williams, Cory T

2015-09-01

Thyroid hormones (THs), key regulators of lipid and carbohydrate metabolism, are likely modulators of energy allocation within and among animal life history stages. Despite their role in modulating metabolism, few studies have investigated whether THs vary among life history stages in free-living animals or if they exhibit stage-specific relationships to total energy expenditure and activity levels. We measured plasma total triiodothyronine (tT3) and thyroxine (tT4) at four, discrete life history stages of female arctic ground squirrels from two different populations in northern Alaska to test whether plasma THs correlate with life history stage-specific changes in metabolic rate and energy demand. We also tested whether THs explained individual variation in aboveground activity levels within life history stages. T3 peaked during lactation and was lowest during pre-hibernation fattening, consistent with known changes in basal metabolism and core body temperature. In contrast, T4 was elevated shortly after terminating hibernation but remained low and stable across other life-history stages in the active season. THs were consistently higher in the population that spent more time above-ground but the relationship between THs and activity varied among life history stages. T3 was positively correlated with activity only during lactation (r(2)=0.50) whereas T4 was positively correlated with activity immediately following lactation (r(2)=0.48) and during fattening (r(2)=0.53). Our results support the hypothesis that THs are an important modulator of basal metabolism but also suggest that the relationship between THs and activity varies among life history stages. Copyright © 2015 Elsevier Inc. All rights reserved.

Rodentia: Sciuridae

African Journals Online (AJOL)

Close chromosomal congruence in two species of ground squirrel: Xerus inauris and X. princeps. (Rodentia: Sciuridae). T.J. Robinson, • .1.0. Skinner and A.S. Haim. Mammal Research Institute, University of Pretoria, Pretoria. Chromosomes from cultured fibroblasts of two southern. African ground squirrel species, Xerus ina ...

Along Came a Spider: Using Live Arthropods in a Predator-Prey Activity

Science.gov (United States)

Richardson, Matthew L.; Hari, Janice

2011-01-01

We developed a predator-prey activity with eighth-grade students in which they used wolf spiders ("Lycosa carolinensis"), house crickets ("Acheta domestica"), and abiotic factors to address how (1) adaptations in predators and prey shape their interaction and (2) abiotic factors modify the interaction between predators and…

Memory of opponents is more potent than visual sign stimuli after social hierarchy has been established

DEFF Research Database (Denmark)

Korzan, W.J.; Höglund, Erik; Watt, M.J.

2007-01-01

During agonistic interactions between male Anolis carolinensis, perception of a visual sign stimulus (darkened eyespots) not only inhibits aggression and promotes initial attainment of dominant social status, but also evokes distinct neuroendocrine responses in each opponent. This study was desig......During agonistic interactions between male Anolis carolinensis, perception of a visual sign stimulus (darkened eyespots) not only inhibits aggression and promotes initial attainment of dominant social status, but also evokes distinct neuroendocrine responses in each opponent. This study...... was designed to examine the effect of eyespot manipulation on behavior and social rank during a second interaction between opponents that had previously established a natural dyadic social hierarchy. Prior to a second interaction, eyespots of familiar size-matched combatants were manipulated to reverse...... information conveyed by this visual signal. Eyespots on the previously dominant male were masked with green paint to indicate low aggression and social status. Previously subordinate males had their eyespots permanently marked with black paint to convey high aggression and status. Opponents were then re...

Diversity, Seasonality, and Context of Mammalian Roadkills in the Southern Great Plains

Science.gov (United States)

Smith-Patten, Brenda D.; Patten, Michael A.

2008-06-01

Thousands of mammals are killed annually from vehicle collisions, making the issue an important one for conservation biologists and environmental managers. We recorded all readily identifiable kills on or immediately adjacent to roads in the southern Great Plains from March 2004-March 2007. We also recorded distance traveled, whether a road was paved or divided, the number of lanes, and prevailing habitat. Surveys were opportunistic and were conducted by car during conditions of good visibility. Over our 239 surveys and >16,500 km traveled, we recorded 1412 roadkills from 18 different mammal species (size ranged from Sciurus squirrels to the white-tailed deer, Odocolieus virginianus). The overall kill rate was 8.50 / 100 km. Four species were prone to collisions: the Virginia opossum ( Didelphis virginiana), nine-banded armadillo ( Dasypus novemcinctus), striped skunk ( Mephitis mephitis), and northern raccoon ( Procyon lotor). Together they accounted for approximately 85% (1198) of all roadkills. Mortality rate differed significantly between 2- and 4-lane roads (8.39 versus 7.79 / 100 km). Kill rates were significantly higher on paved versus unpaved roads (8.60 versus 3.65 / 100 km), but did not depend on whether a road was divided. Roadkills were higher in spring than in fall (1.5×), winter (1.4×), or summer (1.3×). The spring peak (in kills / 100 km) was driven chiefly by the armadillo (2.76 in spring/summer versus 0.73 in autumn/winter) and opossum (2.65 versus 1.47). By contrast, seasonality was dampened by a late winter/early spring peak in skunk mortalities, for which 41% occurred in the 6-week period of mid-February through March. The raccoon did not exhibit a strong seasonal pattern. Our data are consistent with dispersal patterns of these species. Our results underscore the high rate of highway mortality in the southern plains, as well as differences in seasonality and road type that contribute to mortality. Conservation and management efforts should

Wildlife Contact Rates at Artificial Feeding Sites in Texas

Science.gov (United States)

Campbell, Tyler A.; Long, David B.; Shriner, Susan A.

2013-06-01

Given the popularity of feeding white-tailed deer ( Odocoileus virginianus) in Texas and the increasing amount of corn that is distributed, more information is needed on the impacts of this activity on non-target wildlife. Our objectives were to report visitation, intra- and interspecific contact, and contact rates of wildlife at artificial feeding sites in Texas. Our study was conducted at three sites in Kleberg and Nueces counties, Texas. We trapped animals from February to April and August to September, 2009 and marked animals with passive integrated transponder (PIT) tags. At each site and season, we placed one feeder system containing a PIT tag reader within 600 m of trap locations. Readers detected PIT tags from a distance of 25 cm. We determined a contact event to occur when two different PIT tags were detected by feeder systems within 5 s. We recorded 62,719 passes by raccoons ( Procyon lotor), 103,512 passes by collared peccaries ( Pecari tajacu), 2,923 passes by feral swine ( Sus scrofa), 1,336 passes by fox squirrels ( Sciurus niger), and no passes by opossums ( Didelphis virginiana) at feeder systems. For site-season combinations in which contact events occurred, we found intraspecific contact rates (contacts per day) for raccoons, collared peccaries, and feral swine to be 0.81-124.77, 0.69-38.08, and 0.0-0.66, respectively. Throughout our study we distributed ~2,625 kg of whole kernel corn, which resulted in 6,351 contact events between marked wildlife (2.4 contacts per kg of corn). If 136 million kg of corn is distributed in Texas annually, we would expect >5.2 billion unnatural contact events between wildlife would result from this activity each year in Texas. Consequently, we do not believe that it is wise for natural resource managers to maintain artificial feeding sites for white-tailed deer or other wildlife due to pathogen transmission risks.

Paraxerus cepapi

African Journals Online (AJOL)

Male aggressive behaviour towards juveniles in a family group of tree squirrels, Paraxerus cepapi is described. ... Attention was drawn to this family group of squirrels when a high-pitched alann call was heard in the late ... time was spent on mutual grooming and playing by the female, the two subadults and the juveniles.

Prairie dogs increase fitness by killing interspecific competitors.

Science.gov (United States)

Hoogland, John L; Brown, Charles R

2016-03-30

Interspecific competition commonly selects for divergence in ecology, morphology or physiology, but direct observation of interspecific competition under natural conditions is difficult. Herbivorous white-tailed prairie dogs (Cynomys leucurus) employ an unusual strategy to reduce interspecific competition: they kill, but do not consume, herbivorous Wyoming ground squirrels (Urocitellus elegans) encountered in the prairie dog territories. Results from a 6-year study in Colorado, USA, revealed that interspecific killing of ground squirrels by prairie dogs was common, involving 47 different killers; 19 prairie dogs were serial killers in the same or consecutive years, and 30% of female prairie dogs killed at least one ground squirrel over their lifetimes. Females that killed ground squirrels had significantly higher annual and lifetime fitness than non-killers, probably because of decreased interspecific competition for vegetation. Our results document the first case of interspecific killing of competing individuals unrelated to predation (IK) among herbivorous mammals in the wild, and show that IK enhances fitness for animals living under natural conditions. © 2016 The Author(s).

Spin label evidence for the role of lysoglycerophosphatides in cellular membranes of hibernating mammals

Energy Technology Data Exchange (ETDEWEB)

Keith, A D [Pennsylvania State Univ., University Park; Aloia, R C; Lyons, J; Snipes, W; Pengelley, E T

1975-01-01

The phospholipid composition of ground squirrel heart muscle changes during hibernation: more lysoglycerophosphatides are found in the hibernating state than in the active state. Phase transitions inferred from spin label motion occur in the usual manner typical of mammalian mitochondria for the mitochondria and mitochondrial lipids from active squirrels. However, a conspicuous absence of a spin label-detectable phase transition is observed in equivalent preparations from hibernating animals. The addition of lysolecithin to preparations from active squirrels removes the break and induces a straight line in the Arrhenius plot. The lack of a spin label-detectable phase transition in hibernating animals, therefore, is attributed to an increased content of lysoglycerophosphatides present in the phospholipids during hibernation.

The histology of dermal glands of mating Breviceps with comments ...

African Journals Online (AJOL)

CONAWAY, C.H. & METTER, D.E. 1967. Skin glands associated with breeding in Microhyla carolinensis. Copeia 3: 672 - 673. FITCH, H.S. 1956. A field study of the Kansas ant-eating frog,. Gaslrophryne olivacea. Univ. Kans. Publ. Mus. Nal. Hisl. 8;. 275 - 306. INGER, R.F. 1954. Systematics and zoogeography of Philippine.

The relationship of sleep with temperature and metabolic rate in a hibernating primate.

Directory of Open Access Journals (Sweden)

Andrew D Krystal

Full Text Available STUDY OBJECTIVES: It has long been suspected that sleep is important for regulating body temperature and metabolic-rate. Hibernation, a state of acute hypothermia and reduced metabolic-rate, offers a promising system for investigating those relationships. Prior studies in hibernating ground squirrels report that, although sleep occurs during hibernation, it manifests only as non-REM sleep, and only at relatively high temperatures. In our study, we report data on sleep during hibernation in a lemuriform primate, Cheirogaleus medius. As the only primate known to experience prolonged periods of hibernation and as an inhabitant of more temperate climates than ground squirrels, this animal serves as an alternative model for exploring sleep temperature/metabolism relationships that may be uniquely relevant to understanding human physiology. MEASUREMENTS AND RESULTS: We find that during hibernation, non-REM sleep is absent in Cheirogaleus. Rather, periods of REM sleep occur during periods of relatively high ambient temperature, a pattern opposite of that observed in ground squirrels. Like ground squirrels, however, EEG is marked by ultra-low voltage activity at relatively low metabolic-rates. CONCLUSIONS: These findings confirm a sleep-temperature/metabolism link, though they also suggest that the relationship of sleep stage with temperature/metabolism is flexible and may differ across species or mammalian orders. The absence of non-REM sleep suggests that during hibernation in Cheirogaleus, like in the ground squirrel, the otherwise universal non-REM sleep homeostatic response is greatly curtailed or absent. Lastly, ultra-low voltage EEG appears to be a cross-species marker for extremely low metabolic-rate, and, as such, may be an attractive target for research on hibernation induction.

Prototype of an electric 'integral-ecomotor' for the power range up to 1 kW; Funktionsmuster eines Integral-Sparmotors im Leistungsbereich kleiner 1 kW

Energy Technology Data Exchange (ETDEWEB)

Lindegger, M.

2006-11-15

Numerous electric motors of our daily use, with power ratings of about 1 kW operate at rather low efficiencies. Their share in the overall electric consumption is considerable. The aim of the research project consisted in the development of an efficient electric motor with incorporated electronic control ('integral-ecomotor'), which may serve as a substitute for usual variable speed squirrel cage three-phase motor. It was shown that the cost of these new motors of 1 kW power output, built with normalised casings, remain similar to those of squirrel cage three phase motors with inverters. Since 2004, the cost of raw materials as copper or aluminium increased considerably, whereas the cost of Neodymium-Iron-Boron magnets remained rather stable. These facts advocate for energy saving motors making use of permanent magnets, requiring much less copper or aluminium than squirrel cage three phase motors. With integral ecomotors, higher efficiencies are achieved at lower masses as compared to usual squirrel cage three-phase motors. In 2004, a first prototype of this ecomotor using permanent magnets, was built. The advantages of improved performances at lower weight were confirmed. During 2005 and 2006, the technology was then improved and matured in a joint research project with 3 industrial partners. (author)

Ocorrência de Giardia, Cryptosporidium e microsporídios em animais silvestres em área de desmatamento no Estado de São Paulo, Brasil Occurrence of Giardia, Cryptosporidium and microsporidia in wild animals from a deforestation area in the state of São Paulo, Brazil

Directory of Open Access Journals (Sweden)

Maria Anete Lallo

2009-08-01

municipalities of Mogi das Cruzes, Salesópolis and Biritiba-Mirim, in the state of São Paulo (Brazil. Samples were obtained from 46 rodents, 21 marsupials, 16 frogs, 9 bats, 3 tamarins and 3 lizards. For the detection of Giardia, Cryptosporidium and microsporidia it was used, respectively, the floatation technique with lead sulphate, the Kinyoun method and the Gram-Chromotrope staining. The total number of parasitized animals by one of these protozoans was 17.35% (17/98. Cysts of Giardia were found in faecal samples from 2 prehensile-tailed porcupines (Coendou villosus. The three positive animals for Cryptoporidium were rodents - 1 montane akodont (Akodon montensis, 1 ebony akodont (Thaptomyces nigrita and 1 guainan squirrel (Sciurus aestuans. Microporidia spores were seen in the stools of 12 animals - 6 small rodents, including 3 montane akodonts, 1 prehensile-tailed porcupine and 2 pigmy rice rats (Oligoryzomys sp.; 3 marsupials, including 1 gray slender mouse opossum (Marmosops incanus and 2 big eared opossums (Didelphis aurita; 3 hairy-legged vampire bats (Diphylla ecaudata. This is the first description of microsporidiosis in wildlife animals in Brazil. The present study emphasizes the importance of these animals, particularly small mammals, as potential sources of protozoan infection to other animal populations, including man, in areas of deforestation.

Experimental infection of nontarget species of rodents and birds with Brucella abortus strain RB51 vaccine

Science.gov (United States)

Januszewski, M.C.; Olsen, S.C.; McLean, R.G.; Clark, L.; Rhyan, Jack C.

2001-01-01

The Brucella abortus vaccine strain RB51 (SRB51) is being considered for use in the management of bnucellosis in wild bison (Bison bison) and elk (Cervus elaphus) populations in the Greater Yellowstone Area (USA). Evaluation of the vaccines safety in non-target species was considered necessary prior to field use. Between June 1998 and December 1999, ground squirrels (Spermophilus richardsonii, n = 21), deer mice (Peromyscus maniculatus, n = 14), prairie voles (Microtus ochrogaster, n = 21), and ravens (Corvus corax, n = 13) were orally inoculated with SRB51 or physiologic saline. Oral and rectal swabs and blood samples were collected for bacteriologic evaluation. Rodents were necropsied at 8 to 10 wk and 12 to 21 wk post inoculation (PI), and ravens at 7 and 11 wk PI. Spleen, liver and reproductive tissues were collected for bacteriologic and histopathologic evaluation. No differences in clinical signs, appetite, weight loss or gain, or activity were observed between saline- and SRB51-inoculated animals in all four species. Oral and rectal swabs from all species were negative throughout the study. In tissues obtained from SRB51-inoculated animals, the organism was isolated from six of seven (86%) ground squirrels, one of six (17%) deer mice, none of seven voles, and one of five (20%) ravens necropsied at 8, 8, 10, and 7 wk PI, respectively. Tissues from four of seven (57%) SRB51-inoculated ground squirrels were culture positive for the organism 12 wk PI; SRB51 was not recovered from deer mice, voles. or ravens necropsied 12, 21, or 11 wk, respectively, PI. SRB51 was not recovered from saline-inoculated ground squirrels, deer mice, or voles at any time but was recovered from one saline-inoculated raven at necropsy, 7 wk PI, likely attributable to contact with SRB51-inoculated ravens in an adjacent aviary room. Spleen was time primary tissue site of colonization in ground squirrels, followed by the liver and reproductive organs. The results indicate oral exposure to

Nitrogen Isotope Evidence for a Shift in Eastern Beringian Nitrogen Cycle after the Terminal Pleistocene

Science.gov (United States)

Tahmasebi, F.; Longstaffe, F. J.; Zazula, G.

2016-12-01

The loess deposits of eastern Beringia, a region in North America between 60° and 70°N latitude and bounded by Chukchi Sea to the west and the Mackenzie River to the east, are a magnificent repository of Late Pleistocene megafauna fossils. The stable carbon and nitrogen isotope compositions of these fossils are measured to determine the paleodiet of these animals, and hence the paleoenvironment of this ecosystem during the Quaternary. For this approach to be most successful, however, requires consideration of possible changes in nutrient cycling and hence the carbon and nitrogen isotopic compositions of vegetation in this ecosystem. To test for such a shift following the terminal Pleistocene, we analyzed the stable carbon and nitrogen isotope compositions of modern plants and bone collagen of Arctic ground squirrels from Yukon Territory, and fossil plants and bones recovered from Late Pleistocene fossil Arctic ground squirrel nests. The data for modern samples provided a measure of the isotopic fractionation between ground squirrel bone collagen and their diet. The over-wintering isotopic effect of decay on typical forage grasses was also measured to evaluate its role in determining fossil plant isotopic compositions. The grasses showed only a minor change ( 0-1 ‰) in carbon isotope composition, but a major change ( 2-10 ‰) in nitrogen isotope composition over the 317-day experiment. Based on the modern carbon isotope fractionation between ground squirrel bone collagen and their diet, the modern vegetation carbon isotopic baseline provides a suitable proxy for the Late Pleistocene of eastern Beringia, after accounting for the Suess effect. However, the predicted nitrogen isotope composition of vegetation comprising the diet of fossil ground squirrels remains 2.5 ‰ higher than modern grasslands in this area, even after accounting for possible N-15 enrichment during decay. This result suggests a change in N cycling in this region since the Late Pleistocene.

Data logging of body temperatures provides precise information on phenology of reproductive events in a free-living arctic hibernator

Science.gov (United States)

Williams, C.T.; Sheriff, M.J.; Schmutz, J.A.; Kohl, F.; Toien, O.; Buck, C.L.; Barnes, B.M.

2011-01-01

Precise measures of phenology are critical to understanding how animals organize their annual cycles and how individuals and populations respond to climate-induced changes in physical and ecological stressors. We show that patterns of core body temperature (T b) can be used to precisely determine the timing of key seasonal events including hibernation, mating and parturition, and immergence and emergence from the hibernacula in free-living arctic ground squirrels (Urocitellus parryii). Using temperature loggers that recorded T b every 20 min for up to 18 months, we monitored core T b from three females that subsequently gave birth in captivity and from 66 female and 57 male ground squirrels free-living in the northern foothills of the Brooks Range Alaska. In addition, dates of emergence from hibernation were visually confirmed for four free-living male squirrels. Average T b in captive females decreased by 0.5–1.0°C during gestation and abruptly increased by 1–1.5°C on the day of parturition. In free-living females, similar shifts in T b were observed in 78% (n = 9) of yearlings and 94% (n = 31) of adults; females without the shift are assumed not to have given birth. Three of four ground squirrels for which dates of emergence from hibernation were visually confirmed did not exhibit obvious diurnal rhythms in T b until they first emerged onto the surface when T b patterns became diurnal. In free-living males undergoing reproductive maturation, this pre-emergence euthermic interval averaged 20.4 days (n = 56). T b-loggers represent a cost-effective and logistically feasible method to precisely investigate the phenology of reproduction and hibernation in ground squirrels.

Ecological factors related to the widespread distribution of sylvatic Rhodnius ecuadoriensis populations in southern Ecuador

Directory of Open Access Journals (Sweden)

Grijalva Mario J

2012-01-01

Full Text Available Abstract Background Chagas disease transmission risk is a function of the presence of triatomines in domestic habitats. Rhodnius ecuadoriensis is one of the main vectors implicated in transmission of Trypanosoma cruzi in Ecuador. This triatomine species is present in domestic, peridomestic and sylvatic habitats in the country. To determine the distribution of sylvatic populations of R. ecuadoriensis and the factors related to this distribution, triatomine searches were conducted between 2005 and 2009 in southern Ecuador. Methods Manual triatomine searches were conducted by skilled bug collectors in 23 communities. Sylvatic searched sites were selected by a directed sampling, where microhabitats were selected by the searchers and b random sampling, where sampling points where randomly generated. Domiciliary triatomine searches were conducted using the one man-hour method. Natural trypanosome infection was determined by microscopic examination and PCR. Generalized linear models were used to test the effect of environmental factors on the presence of sylvatic triatomines. Results In total, 1,923 sylvatic individuals were collected representing a sampling effort of 751 man-hours. Collected sylvatic triatomines were associated with mammal and bird nests. The 1,219 sampled nests presented an infestation index of 11.9%, a crowding of 13 bugs per infested nest, and a colonization of 80% of the nests. Triatomine abundance was significantly higher in squirrel (Sciurus stramineus nests located above five meters from ground level and close to the houses. In addition, 8.5% of the 820 examined houses in the same localities were infested with triatomines. There was a significant correlation between R. ecuadoriensis infestation rates found in sylvatic and synanthropic environments within communities (p = 0.012. Parasitological analysis revealed that 64.7% and 15.7% of the sylvatic bugs examined (n = 300 were infected with Trypanosoma cruzi and T. rangeli

Ecological factors related to the widespread distribution of sylvatic Rhodnius ecuadoriensis populations in southern Ecuador

Science.gov (United States)

2012-01-01

Background Chagas disease transmission risk is a function of the presence of triatomines in domestic habitats. Rhodnius ecuadoriensis is one of the main vectors implicated in transmission of Trypanosoma cruzi in Ecuador. This triatomine species is present in domestic, peridomestic and sylvatic habitats in the country. To determine the distribution of sylvatic populations of R. ecuadoriensis and the factors related to this distribution, triatomine searches were conducted between 2005 and 2009 in southern Ecuador. Methods Manual triatomine searches were conducted by skilled bug collectors in 23 communities. Sylvatic searched sites were selected by a) directed sampling, where microhabitats were selected by the searchers and b) random sampling, where sampling points where randomly generated. Domiciliary triatomine searches were conducted using the one man-hour method. Natural trypanosome infection was determined by microscopic examination and PCR. Generalized linear models were used to test the effect of environmental factors on the presence of sylvatic triatomines. Results In total, 1,923 sylvatic individuals were collected representing a sampling effort of 751 man-hours. Collected sylvatic triatomines were associated with mammal and bird nests. The 1,219 sampled nests presented an infestation index of 11.9%, a crowding of 13 bugs per infested nest, and a colonization of 80% of the nests. Triatomine abundance was significantly higher in squirrel (Sciurus stramineus) nests located above five meters from ground level and close to the houses. In addition, 8.5% of the 820 examined houses in the same localities were infested with triatomines. There was a significant correlation between R. ecuadoriensis infestation rates found in sylvatic and synanthropic environments within communities (p = 0.012). Parasitological analysis revealed that 64.7% and 15.7% of the sylvatic bugs examined (n = 300) were infected with Trypanosoma cruzi and T. rangeli respectively, and 8% of the

Response and Resiliency of Wildlife and Vegetation to Large-Scale Wildfires and Climate Change in the North Cascades

Science.gov (United States)

Bartowitz, K.; Morrison, P.; Romain-Bondi, K.; Smith, C. W.; Warne, L.; McGill, D.

2016-12-01

Changing climatic patterns have affected the western US in a variety of ways: decreases in precipitation and snowpack, earlier spring snowmelt, and increased lightning strikes have created a drier, more fire-prone system, despite variability in these characteristics. Wildfires are a natural phenomenon, but have been suppressed for much of the past century. Effects of this evolving fire regime on native vegetation and wildlife are not well understood. Increased frequency and intensity of fires coupled with subsequent drought and extreme heat may inhibit or alter recovery of native ecosystems. We are currently investigating how a mega-fire has affected presence of western gray squirrels (Sciurus griseus, WGS) in the North Cascades, and the mortality, survival, and recovery of vegetation following these fires and extreme drought. The Methow Valley in WA experienced a record-breaking wildfire in 2014, which disturbed nearly 50% of priority habitat of the North Cascades population of WGS. WGS were studied at the same pre and post-fire plots. WGS were present at over half of the post-burn plots (58%). There was a significant difference in the number of WGS hair samples collected in different levels of remaining vegetation: the most in moderate, few in low, and none in high. Vegetation recovery was assessed through field data, and a chronosequence of satellite images and aerial photography. 75% of the 2014 fire burned non-forested vegetation. Ponderosa pine forests comprised the rest. The forests experienced about 70% initial mortality. Recovery of the forest appears slower than in the shrub-steppe. First year seedling survival was poor due to an extremely hot, dry summer, while second year survival appears higher due to a cool, moist spring and summer. One year after a large, multi-severity fire we found WGS may be more resilient to disturbance such as fires than previously thought. Future studies of WGS will help elucidate long-term response to large-scale fires, and

Coevolution between Hispaniolan crossbills and pine: does more time allow for greater phenotypic escalation at lower latitude?

Science.gov (United States)

Parchman, Thomas L; Benkman, Craig W; Mezquida, Eduardo T

2007-09-01

Crossbills (Aves: Loxia) and several conifers have coevolved in predator-prey arms races over the last 10,000 years. However, the extent to which coevolutionary arms races have contributed to the adaptive radiation of crossbills or to any other adaptive radiation is largely unknown. Here we extend our previous studies of geographically structured coevolution by considering a crossbill-conifer interaction that has persisted for a much longer time period and involves a conifer with more variable annual seed production. We examined geographic variation in the cone and seed traits of two sister species of pines, Pinus occidentalis and P. cubensis, on the islands of Hispaniola and Cuba, respectively. We also compared the Hispaniolan crossbill (Loxia megaplaga) to its sister taxa the North American white-winged crossbill (Loxia leucoptera leucoptera). The Hispaniolan crossbill is endemic to Hispaniola whereas Cuba lacks crossbills. In addition and in contrast to previous studies, the variation in selection experienced by these pines due to crossbills is not confounded by the occurrence of selection by tree squirrels (Tamiasciurus and Sciurus). As predicted if P. occidentalis has evolved defenses in response to selection exerted by crossbills, cones of P. occidentalis have scales that are 53% thicker than those of P. cubensis. Cones of P. occidentalis, but not P. cubensis, also have well-developed spines, a known defense against vertebrate seed predators. Consistent with patterns of divergence seen in crossbills coevolving locally with other conifers, the Hispaniolan crossbill has evolved a bill that is 25% deeper than the white-winged crossbill. Together with phylogenetic analyses, our results suggest that predator-prey coevolution between Hispaniolan crossbills and P. occidentalis over approximately 600,000 years has caused substantial morphological evolution in both the crossbill and pine. This also indicates that cone crop fluctuations do not prevent crossbills and

Squirrels With Scissors

DEFF Research Database (Denmark)

Skjerning, Halfdan; Clemmensen, Louise Thorsø

2016-01-01

Reviews the film Me and Earl and the Dying Girl (2015) directed by Alfonso Gomez-Rejon (2015). The film portrays the development of a friendship between three young people, one of them newly diagnosed with cancer. The film is a humorous declaration of love and the power of friendship. It is about...... meaning in a meaningless situation by selflessly giving to another person in ways that we all can give. (PsycINFO Database Record (c) 2016 APA, all rights reserved)...

Traffics and wildlife: A preliminary study on road-kill

OpenAIRE

Rustiati, Elly Lestari

2012-01-01

This paper presents the preliminary finding on road kill survey by direct observations onthe high ways. The road-kills recorded of small wildlife, including medium size-mammal (2.50%, n =1), birds (5.00%, n = 2) and small mammals (92.50%, n = 37). The small mammals include the mostcommon mammals in the areas, squirrels, raccoons, skunks and woodchuck. Of mammals, squirrels(35.00%) were the highest recorded, followed by woodchucks (25.00%), mice/shrew (17.50%),raccoons (10.00%), skunk (5.00%) ...

Interspecies radioimmunoassay for the major structural proteins of primate type-D retroviruses

International Nuclear Information System (INIS)

Colcher, D.; Teramoto, Y.A.; Schlom, J.

1977-01-01

A competition radioimmunoassay has been developed in which type-D retroviruses from three primate species compete. The assay utilizes the major structural protein (36,000 daltons) of the endogenous squirrel monkey retrovirus and antisera directed against the major structural protein (27,000 daltons) of the Mason-Pfizer monkey virus isolated from rhesus monkeys. Purified preparations of both viruses grown in heterologous cells, as well as extracts of heterologous cells infected with squirrel monkey retrovirus or Mason-Pfizer monkey virus, compete completely in the assay. Addition of an endogenous virus of the langur monkey also results in complete blocking. No blocking in the assay is observed with type-C baboon viruses, woolly monkey virus, and gibbon virus. Various other type-C and type-B viruses also showed no reactivity. An interspecies assay has thus been developed that recognizes the type-D retroviruses from both Old World monkey (rhesus and langur) and New World monkey (squirrel) species

On the validity of the classical hydrodynamic lubrication theory applied to squeeze film dampers

International Nuclear Information System (INIS)

Danaila, S; Moraru, L

2010-01-01

Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. The SFD - squirrel cage combination is probably the most used system for tuning the stiffness and damping of the supports for rotors installed on ball bearings. Squeeze film dampers are essentially hydrodynamic bearings which contain the ball bearings housings of ball-bearings supported shafts. Consequently, the oil film within the SFD are influenced only by the precession and nutation of the shaft, that is the flow of the oil within the damper is not directly influenced by the spin of the rotor. However, in the classical theory, the flow in the thin film is also governed by the Reynolds equation. In this paper, some of the limits of the classical theory of the SFD are discussed and theoretical and experimental studies, which illustrate the ideas presented herein, are presented as well. The orbits of an unbalanced rotor that is supported by a ball-bearings-SFD-squirrel-cage assembly at one end and by rigidly mounted ball bearings at the other end are computed using the bearing forces provided by the classical short bearing theory. The numerical model also includes the properties of the squirrel cage. The parameters of the squirrel cage were measured, together with the effect of the friction within the assembly. Experimental unbalance responses were also collected for various rotation speeds and unbalances to validate the numerical simulations.

Mamíferos silvestres de la Reserva Ecológica del Pedregal de San Ángel en Ciudad Universitaria, Universidad Nacional Autónoma de México, México, D. F. Wild mammals of Reserva Ecológica del Pedregal de San Ángel, Ciudad Universitaria, UNAM, Mexico, D.F.

OpenAIRE

Yolanda Hortelano-Moncada; Fernando A. Cervantes; Aída Trejo-Ortiz

2009-01-01

Se realizó un inventario de las especies de mamíferos que habitan en la Reserva Ecológica del Pedregal de San Ángel (REPSA). Los datos se obtuvieron a partir de registros de colecciones científicas, de recolectas recientes en el área y de consultas en literatura especializada. Los resultados comprenden 628 registros acumulados desde 1943 y corresponden a 33 especies, agrupadas en 28 géneros, 15 familias y 6 órdenes de mamíferos. La ardilla gris (Sciurus aureogaster nigrescens) y el ratón del ...

Influence of coarse woody debris on the soricid community in southeastern Coastal Plain pine stands.

Energy Technology Data Exchange (ETDEWEB)

Davis, Justin, C.; Castleberry, Steven, B.; Kilgo, John, C.

2010-07-01

Shrew abundance has been linked to the presence of coarse woody debris (CWD), especially downed logs, in many regions in the United States. We investigated the importance of CWD to shrew communities in managed upland pine stands in the southeastern United States Coastal Plain. Using a randomized complete block design, 1 of the following treatments was assigned to twelve 9.3-ha plots: removal (n 5 3; all downed CWD _10 cm in diameter and _60 cm long removed), downed (n 5 3; 5-fold increase in volume of downed CWD), snag (n 5 3; 10-fold increase in volume of standing dead CWD), and control (n 5 3; unmanipulated). Shrews (Blarina carolinensis, Sorex longirostris, and Cryptotis parva) were captured over 7 seasons from January 2007 to August 2008 using drift-fence pitfall trapping arrays within treatment plots. Topographic variables were measured and included as treatment covariates. More captures of B. carolinensis were made in the downed treatment compared to removal, and captures of S. longirostris were greater in downed and snag compared to removal. Captures of C. parva did not differ among treatments. Captures of S. longirostris were positively correlated with slope. Our results suggest that abundance of 2 of the 3 common shrew species of the southeastern Coastal Plain examined in our study is influenced by the presence of CWD.

The peculiarities of the masticator muscles in rodents

Directory of Open Access Journals (Sweden)

C. Spataru

2013-06-01

Full Text Available Comparative research concerning masticatory musculature in squirrel, muskrat and rabbit, take into account the emphasizing and morphofunctional interpretation of the osteomuscular particularities involved in the prehension and mastication processes. The development of the coronoid process on the muskrat and squirrel demonstrates the growing of the force when raising the mandible by increasing the action force attached to the temporal muscle, with insertion on the coronoid process. In comparison with that, in the case of rabbits, both the coronoid process and the temporal muscle are reduced. From a philogenetic point of view, it has been found that the species that have the articular condyle lowered at or under the level of the dental tables (carnivores present a greater pressure force between the dental tables. Analyzing this aspect of the rodents taken into discussion, we noticed the lowering of the articular condyle up to the inferior molars' plane, in the case of squirrels and muskrats, but through obliquity, namely through cranial caudal and dorsoventral movement. This peculiarity is emphasized through the analysis of the angle formed by the axis of the mandible recurved branch (passing through the mandibular condyle with the axis of the horizontal branch of the mandible, where it was noticed that along with the increase in the angle formed by the two axes, which becomes an obtuse 160 degree angle on the squirrel and 130 degrees on the muskrat, there is also a lowering of the articular condyle up to the molar level, while in the case of carnivores, the lowering of the condyle is done without the modification of the angle between the two axes, which measures approximately 90 degrees.

Hemoglobin function and allosteric regulation in semi-fossorial rodents (family Sciuridae) with different altitudinal ranges

Science.gov (United States)

Revsbech, Inge G.; Tufts, Danielle M.; Projecto-Garcia, Joana; Moriyama, Hideaki; Weber, Roy E.; Storz, Jay F.; Fago, Angela

2013-01-01

SUMMARY Semi-fossorial ground squirrels face challenges to respiratory gas transport associated with the chronic hypoxia and hypercapnia of underground burrows, and such challenges are compounded in species that are native to high altitude. During hibernation, such species must also contend with vicissitudes of blood gas concentrations and plasma pH caused by episodic breathing. Here, we report an analysis of hemoglobin (Hb) function in six species of marmotine ground squirrels with different altitudinal distributions. Regardless of their native altitude, all species have high Hb–O2 affinities, mainly due to suppressed sensitivities to allosteric effectors [2,3-diphosphoglycerate (DPG) and chloride ions]. This suppressed anion sensitivity is surprising given that all canonical anion-binding sites are conserved. Two sciurid species, the golden-mantled and thirteen-lined ground squirrel, have Hb–O2 affinities that are characterized by high pH sensitivity and low thermal sensitivity relative to the Hbs of humans and other mammals. The pronounced Bohr effect is surprising in light of highly unusual amino acid substitutions at the C-termini that are known to abolish the Bohr effect in human HbA. Taken together, the high O2 affinity of sciurid Hbs suggests an enhanced capacity for pulmonary O2 loading under hypoxic and hypercapnic conditions, while the large Bohr effect should help to ensure efficient O2 unloading in tissue capillaries. In spite of the relatively low thermal sensitivities of the sciurid Hbs, our results indicate that the effect of hypothermia on Hb oxygenation is the main factor contributing to the increased blood–O2 affinity in hibernating ground squirrels. PMID:24172889

Thermal reactionomes reveal divergent responses to thermal extremes in warm and cool-climate ant species

DEFF Research Database (Denmark)

Stanton-Geddes, John; Nguyen, Andrew; Chick, Lacy

2016-01-01

across an experimental gradient. We characterized thermal reactionomes of two common ant species in the eastern U.S, the northern cool-climate Aphaenogaster picea and the southern warm-climate Aphaenogaster carolinensis, across 12 temperatures that spanned their entire thermal breadth.......The distributions of species and their responses to climate change are in part determined by their thermal tolerances. However, little is known about how thermal tolerance evolves. To test whether evolutionary extension of thermal limits is accomplished through enhanced cellular stress response...

Nitrogen isotopes suggest a change in nitrogen dynamics between the Late Pleistocene and modern time in Yukon, Canada

Science.gov (United States)

Longstaffe, Fred J.; Zazula, Grant

2018-01-01

A magnificent repository of Late Pleistocene terrestrial megafauna fossils is contained in ice-rich loess deposits of Alaska and Yukon, collectively eastern Beringia. The stable carbon (δ13C) and nitrogen (δ15N) isotope compositions of bone collagen from these fossils are routinely used to determine paleodiet and reconstruct the paleoecosystem. This approach requires consideration of changes in C- and N-isotope dynamics over time and their effects on the terrestrial vegetation isotopic baseline. To test for such changes between the Late Pleistocene and modern time, we compared δ13C and δ15N for vegetation and bone collagen and structural carbonate of some modern, Yukon, arctic ground squirrels with vegetation and bones from Late Pleistocene fossil arctic ground squirrel nests preserved in Yukon loess deposits. The isotopic discrimination between arctic ground squirrel bone collagen and their diet was measured using modern samples, as were isotopic changes during plant decomposition; Over-wintering decomposition of typical vegetation following senescence resulted in a minor change (~0–1 ‰) in δ13C of modern Yukon grasses. A major change (~2–10 ‰) in δ15N was measured for decomposing Yukon grasses thinly covered by loess. As expected, the collagen-diet C-isotope discrimination measured for modern samples confirms that modern vegetation δ13C is a suitable proxy for the Late Pleistocene vegetation in Yukon Territory, after correction for the Suess effect. The N-isotope composition of vegetation from the fossil arctic ground squirrel nests, however, is determined to be ~2.8 ‰ higher than modern grasslands in the region, after correction for decomposition effects. This result suggests a change in N dynamics in this region between the Late Pleistocene and modern time. PMID:29447202

Mechanisms of spectral tuning in the RH2 pigments of Tokay gecko and American chameleon

OpenAIRE

Takenaka, Naomi; Yokoyama, Shozo

2007-01-01

At present, molecular bases of spectral tuning in rhodopsin-like (RH2) pigments are not well understood. Here, we have constructed the RH2 pigments of nocturnal Tokay gecko (Gekko gekko) and diurnal American chameleon (Anolis carolinensis) as well as chimeras between them. The RH2 pigments of the gecko and chameleon reconstituted with 11-cis-retinal had the wavelengths of maximal absorption (λmax’s) of 467 and 496 nm, respectively. Chimeric pigment analyses indicated that 76–86%, 14–24%, and ...

Diagnóstico de problemas de asimetrías rotóricas en un motor de inducción de gran potencia. // Diagnostic of high power induction motors failures.

Directory of Open Access Journals (Sweden)

N. Soto Salvá

2007-05-01

Full Text Available Este diagnóstico se ha realizado en un total de 14 motores de inducción, todos ellos de jaula de ardilla y de 6 000 voltios.Se hará referencia al último diagnóstico realizado que se trata de un motor de una bomba de agua de alimentar caldera tipo4A3M-2500/6000 CT4 de una unidad generadora de electricidad de 100 MW. Mediante las técnicas de diagnósticoempleadas se logró determinar roturas de barras en la jaula de ardilla del rotor del motor.Palabras claves: Motor de Inducción, espectros, diagnóstico, jaula de ardilla, fallas.____________________________________________________________________________Abstract:This diagnosis has been carried out in a total of 14 induction motors, all them of squirrel cage and of 6 000 volts.Reference will be made to the last carried out diagnosis that it is a motor of a bomb of water of feeding boiler type 4A3M-2500/6000 CT4 of a generating unit of electricity of 100 MW. By means of the techniques of diagnosis employees it waspossible to determine breaks of bars in the cage of squirrel of the rotor in the motor.Key Words: Motor of induction, spectrum, diagnostic, squirrel cage, failures..

Fylogeografie a konzervační genetika sysla obecného

OpenAIRE

ŘÍČANOVÁ, Štěpánka

2012-01-01

Phylogeography and conservation genetics of the European ground squirrel was studied in the whole range of its distribution revealing evolutionary conservation units which are important for future conservation management of the species.

ESTABLISHED MODES AND STATIC CHARACTERISTICS OF THREE-PHASE ASYNCHRONOUS MOTOR POWERED WITH SINGLE PHASE NETWORK

Directory of Open Access Journals (Sweden)

V. S. Malyar

2016-01-01

Full Text Available A mathematical model is developed to study the operation of three-phase asynchronous motor with squirrel-cage rotor when the stator winding is powered from a single phase network. To create a rotating magnetic field one of the phases is fed through the capacitor. Due to the asymmetry of power feed not only transients, but the steady-state regimes are dynamic, so they are described by differential equations in any coordinate system. Their study cannot be carried out with sufficient adequacy on the basis of known equivalent circuits and require the use of dynamic parameters. In the mathematical model the state equations of the circuits of the stator and rotor are composed in the stationary three phase coordinate system. Calculation of the established mode is performed by solving the boundary problem that makes it possible to obtain the coordinate dependences over the period, without calculation of the transient process. In order to perform it, the original nonlinear differential equations are algebraized by approximating the variables with the use of cubic splines. The resulting nonlinear system of algebraic equations is a discrete analogue of the initial system of differential equations. It is solved by parameter continuation method. To calculate the static characteristics as a function of a certain variable, the system is analytically differentiated, and then numerically integrated over this variable. In the process of integration, Newton's refinement is performed at each step or at every few steps, making it possible to implement the integration in just a few steps using Euler's method. Jacobi matrices in both cases are the same. To account for the current displacement in the rods of the squirrel-cage rotor, each of them, along with the squirrel-cage rings, is divided in height into several elements. This results in several squirrel-cage rotor windings which are represented by three-phase windings with magnetic coupling between them.

Plague Factsheet

Science.gov (United States)

... Many other rodent species, for instance, prairie dogs, wood rats, chipmunks, and other ground squirrels and their ... or by citizens reporting rodents found sick or dead to local health departments. Use of appropriate and ...

Thermoregulatory Responses of Febrile Monkeys During Microwave Exposure

National Research Council Canada - National Science Library

Adair, E

1997-01-01

.... In a controlled ambient temperature of 26 degrees C, autonomic mechanisms of heat production and heat loss were measured in febrile squirrel monkeys during 30-min exposures to 450 or 2450 MHz CW MW...

The supermodule insertion tool of the CMS electromagnetic calorimeter and the first trial insertion of a supermodule.

CERN Multimedia

Maximilien Brice

2006-01-01

The first trial insertion of a complete Electromagnetic Calorimeter (ECAL) "supermodule" (1700 lead-tungstate crystals, with support structures, light detectors (avalanche photodiodes), readout electronics and cooling system) was performed on 1st March. This delicate operation - sliding a 2-tonne 3m-long object onto support rails (in real life these are attached to the barrel hadron calorimeter (HCAL)) - made use of a custom designed "squirrel cage". The rotatable squirrel cage allows the insertion of any supermodule into any of the 18 positions, including very fine (sub-mm) adjustments. The first supermodule will be inserted into the real HCAL later this month in preparation for the "magnet test and cosmic-ray challenge" (MTCC). In the first image the supermodule is in the centre and the alignment disks are highlighted by the flash.

[Seasonal changes in tumor necrosis factor production in hibernating animals in normal conditions and under the effects of electromagnetic and ionizing radiation].

Science.gov (United States)

Ogaĭ, V B; Novoselova, E G; Makar, V R; Kolaeva, S G

2002-01-01

Production of tumor necrosis factor (TNF) has been investigated in peritoneal macrophages and splenic T cells of Arctic Yakutian ground squirrel (Citellus Undulatus Pallas) upon in vitro action of electromagnetic and ionizing radiation during annual cycle. The significant activation of TNF production in the cells of awaken ground squirrels in winter and increasing level of the lymphokine production at spring-summer period has been indicated. The level of TNF production in splenic T cells was not changed during whole year. The electromagnetic radiation (EMR) of low intensity (8.15-18 GHz, 1 microW/cm2) induced an augmentation of both secretory and proliferative activity in TNF-producing cells. Ionizing radiation suppressed T cell proliferation, but the doses 2 and 5 Gy resulted in a significant stimulation of TNF production in T cells and macrophages.

Postembryonic Nephrogenesis and Persistence of Six2-Expressing Nephron Progenitor Cells in the Reptilian Kidney.

Directory of Open Access Journals (Sweden)

Troy Camarata

Full Text Available New nephron formation (nephrogenesis ceases in mammals around birth and is completely absent in adults. In contrast, postembryonic nephrogenesis is well documented in the mesonephric kidneys of fishes and amphibians. The transient mesonephros in reptiles (including birds and mammals is replaced by the metanephros during embryogenesis. Thus, one may speculate that postembryonic nephrogenesis is restricted to the mesonephric kidney. Previous reports have suggested the metanephros of non-avian reptiles (hereafter reptiles may continually form nephrons throughout life. We investigated the presence of adult nephrogenesis in reptiles by examining adult kidneys from several species including Trachemys scripta, Chrysemys picta, Boa constrictor, Tupinambis tegu, Anolis carolinensis, and Alligator mississipiensis among others. We found that all major reptilian groups (Testudines, Crocodylia, and Squamates showed the presence of adult nephrogenesis. The total amount of nephrogenesis varied greatly between species with turtles displaying the highest density of nephrogenesis. In contrast, we were unable to detect adult nephrogenesis in monotremes, and in the iguanid A. carolinensis. Nephron progenitor cells express the transcription factor Six2, which in mammals, becomes downregulated as the progenitor cell population is exhausted and nephrogenesis ends. Using the alligator as a model, we were able to detect Six2-positive cap mesenchyme cells in the adult kidney, which spatially correlated with areas of nephrogenesis. These results suggest that the metanephric kidney of reptiles has maintained the ability to continually grow new nephrons during postembryonic life, a process lost early in mammalian evolution, likely due to the persistence of a Six2-expressing progenitor cell population.

Postembryonic Nephrogenesis and Persistence of Six2-Expressing Nephron Progenitor Cells in the Reptilian Kidney.

Science.gov (United States)

Camarata, Troy; Howard, Alexis; Elsey, Ruth M; Raza, Sarah; O'Connor, Alice; Beatty, Brian; Conrad, Jack; Solounias, Nikos; Chow, Priscilla; Mukta, Saima; Vasilyev, Aleksandr

2016-01-01

New nephron formation (nephrogenesis) ceases in mammals around birth and is completely absent in adults. In contrast, postembryonic nephrogenesis is well documented in the mesonephric kidneys of fishes and amphibians. The transient mesonephros in reptiles (including birds) and mammals is replaced by the metanephros during embryogenesis. Thus, one may speculate that postembryonic nephrogenesis is restricted to the mesonephric kidney. Previous reports have suggested the metanephros of non-avian reptiles (hereafter reptiles) may continually form nephrons throughout life. We investigated the presence of adult nephrogenesis in reptiles by examining adult kidneys from several species including Trachemys scripta, Chrysemys picta, Boa constrictor, Tupinambis tegu, Anolis carolinensis, and Alligator mississipiensis among others. We found that all major reptilian groups (Testudines, Crocodylia, and Squamates) showed the presence of adult nephrogenesis. The total amount of nephrogenesis varied greatly between species with turtles displaying the highest density of nephrogenesis. In contrast, we were unable to detect adult nephrogenesis in monotremes, and in the iguanid A. carolinensis. Nephron progenitor cells express the transcription factor Six2, which in mammals, becomes downregulated as the progenitor cell population is exhausted and nephrogenesis ends. Using the alligator as a model, we were able to detect Six2-positive cap mesenchyme cells in the adult kidney, which spatially correlated with areas of nephrogenesis. These results suggest that the metanephric kidney of reptiles has maintained the ability to continually grow new nephrons during postembryonic life, a process lost early in mammalian evolution, likely due to the persistence of a Six2-expressing progenitor cell population.

Postembryonic Nephrogenesis and Persistence of Six2-Expressing Nephron Progenitor Cells in the Reptilian Kidney

Science.gov (United States)

Camarata, Troy; Howard, Alexis; Elsey, Ruth M.; Raza, Sarah; O’Connor, Alice; Beatty, Brian; Conrad, Jack; Solounias, Nikos; Chow, Priscilla; Mukta, Saima; Vasilyev, Aleksandr

2016-01-01

New nephron formation (nephrogenesis) ceases in mammals around birth and is completely absent in adults. In contrast, postembryonic nephrogenesis is well documented in the mesonephric kidneys of fishes and amphibians. The transient mesonephros in reptiles (including birds) and mammals is replaced by the metanephros during embryogenesis. Thus, one may speculate that postembryonic nephrogenesis is restricted to the mesonephric kidney. Previous reports have suggested the metanephros of non-avian reptiles (hereafter reptiles) may continually form nephrons throughout life. We investigated the presence of adult nephrogenesis in reptiles by examining adult kidneys from several species including Trachemys scripta, Chrysemys picta, Boa constrictor, Tupinambis tegu, Anolis carolinensis, and Alligator mississipiensis among others. We found that all major reptilian groups (Testudines, Crocodylia, and Squamates) showed the presence of adult nephrogenesis. The total amount of nephrogenesis varied greatly between species with turtles displaying the highest density of nephrogenesis. In contrast, we were unable to detect adult nephrogenesis in monotremes, and in the iguanid A. carolinensis. Nephron progenitor cells express the transcription factor Six2, which in mammals, becomes downregulated as the progenitor cell population is exhausted and nephrogenesis ends. Using the alligator as a model, we were able to detect Six2-positive cap mesenchyme cells in the adult kidney, which spatially correlated with areas of nephrogenesis. These results suggest that the metanephric kidney of reptiles has maintained the ability to continually grow new nephrons during postembryonic life, a process lost early in mammalian evolution, likely due to the persistence of a Six2-expressing progenitor cell population. PMID:27144443

Dicty_cDB: Contig-U16580-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 0.0 10 ( DQ015713 ) Chlamydomonas chlamydogama strain UTEX 102 26S ri... 375 0.0 9 ( EU272562 ) Eudendrium racemosum voucher persona...A gene, part... 420 0.0 9 ( EU272561 ) Ectopleura dumortieri voucher personal:A. Lindner... 396 0.0 10 ( AY0...0 9 ( EU272552 ) Clava multicornis voucher personal:P. Schuchert:S... 396 0.0 9 ( EU272549 ) Bougainvillia carolinensis voucher perso... l... 396 0.0 9 ( EU272571 ) Koellikerina fasciculata voucher personal:P. Schu...... ribosoma... 357 0.0 10 ( EU272574 ) Lizzia blondina voucher personal:P. Schuchert:Sch... 396 0.0 9 ( EU2725

Two distinct gamma-2 herpesviruses in African green monkeys: a second gamma-2 herpesvirus lineage among old world primates?

NARCIS (Netherlands)

Greensill, J.; Sheldon, J. A.; Renwick, N. M.; Beer, B. E.; Norley, S.; Goudsmit, J.; Schulz, T. F.

2000-01-01

Primate gamma-2 herpesviruses (rhadinoviruses) have so far been found in humans (Kaposi's sarcoma-associated herpesvirus [KSHV], also called human herpesvirus 8), macaques (Macaca spp.) (rhesus rhadinovirus [RRV] and retroperitoneal fibromatosis herpesvirus [RFHV]), squirrel monkeys (Saimiri

Electromagnetic modeling of the rings of the squirrel cage of an induction motor; Modelado electromagnetico de los anillos de la jaula de ardilla de un motor de induccion

Energy Technology Data Exchange (ETDEWEB)

Limones Montoya, Juan Carlos

2004-03-15

An electromagnetic lineal model of a three-phase induction motor was developed in this thesis. The Finite element method in two dimensions was used. The model formulation takes into account the coupling with the stator wires and solid conductors of the rotor. In other words, the stator phases and squirrel-cage end-rings are considered in the model. The resulting set of electric-circuit and magnetic-field equations are solved simultaneously with the Incomplete Cholesky Bi-Conjugate Gradient Method using a matrix storage technique known as symmetric coordinate storage. The model was programmed in the C programming language. The magnetic field model is represented by the diffusion equation, which allows to compute the induced Eddy currents in the conducting material due to the sinusoidal stator excitation. The modelled induction motor has a rated power of 2.2 kW, 220 V, 9.6/11.0 A, 60 Hz and it can be operated at the speeds of 1750/1150 rpm. It is located in the Laboratorio de Propulsion at the Instituto Tecnologico de la Laguna. [Spanish] En este trabajo de tesis se desarrollo un modelo electromagnetico lineal de un motor de induccion trifasico utilizando el Metodo de Elemento Finito en dos dimensiones, en el cual se incluye la formulacion de sistemas acoplados para los conductores delgados y gruesos presentes en el estator y rotor respectivamente. Es decir, se incluyen en el modelo las fases de alimentacion y los anillos de cortocircuito del rotor de jaula de ardilla. Las ecuaciones electricas y magneticas derivadas del modelo se resuelven de manera acoplada con el Metodo del Gradiente BiConjugado con Precondicionamiento de Cholesky Incompleto empleando el sistema de Empaquetamiento de Coordenadas, cuyo codigo se desarrollo en el lenguaje de programacion C. En este modelo se resuelve la ecuacion de difusion, mediante la cual se determinan las corrientes de Eddy que se inducen en el material conductor debido a la presencia de fuentes de alimentacion senoidales. El

performance characteristics of an armature voltage controlled dc motor

African Journals Online (AJOL)

Dr Obe

. INTRODUCTION. The good control properties of the d.c. motor have made possible its initial large scale application in industry [1]. In spite of the present superiority of the solid state squirrel cage induction motor drive, especially at supply ...

Good and bad in the hibernating brain

NARCIS (Netherlands)

Strijkstra, AM

2006-01-01

Hibernators survive long periods of time without behavioural activity. To minimize energy expenditure, hibernators use the natural hypometabolic state of torpor. Deep torpor in ground squirrels is accompanied by reduction of brain activity, and is associated with changes in electrical activity

Autoshaping in Japanese Monkeys (Macaca Fuscata)

OpenAIRE

Itakura, Shoji; Fushimi, Takao; Asano, Toshio; Shoji, Itakura; Takao, Fushimi; Toshio, Asano

1992-01-01

Three Japanese monkeys were exposed to autoshaping and omission procedures. The Japanese momkeys seemed to be more sensitive to response-reinforcer contingency than to stimulus-reinforcer contingency. These results were compared with pigeons and squirrel monkeys in the previous reports.

Coevolution of Symbiotic Species

OpenAIRE

Leok, Boon Tiong Melvin

1996-01-01

This paper will consider the coevolution of species which are symbiotic in their interaction. In particular, we shall analyse the interaction of squirrels and oak trees, and develop a mathematical framework for determining the coevolutionary equilibrium for consumption and production patterns.

Investigation of some characteristics of enzymes that ensure the process of membrane digestion in paddlefish and Russian sturgeon

Directory of Open Access Journals (Sweden)

A. N. Nevalennyy

2010-01-01

Full Text Available Complex research of characteristics of some enzymes which are carrying out membrane hydrolysis of food at a spoonbilled cat and Russian sturgeon is carried out. High thermostability enzymes the squirrel of all investigated enzymes is marked.

Feeding habits and comparative feeding rates of three southern ...

African Journals Online (AJOL)

Many of the forest plant species have fruits and seeds which are unattractive to or too ...... non (1978) found that the competing red and grey squirrel in. Great Britain had ..... Resource overlap, interspecific interactions and the distribution of the ...

Imperative function of electron beams in low-energy plasma focus ...

Indian Academy of Sciences (India)

2015-04-12

SXR) spectral lines of highly charged heavy metal ions [11] because of its ... potential device for generating X-rays with enhanced efficiency ... of a squirrel cage with an inner diameter of 3.2 cm (figure 2). ... Faraday cup plate. 0.1.

Environmental Assessment for the Expansion of the Elmendorf AFB Gravel Pit

Science.gov (United States)

2008-04-01

portions of the herd migrate off base in fall and winter. To help reduce moose numbers on military lands, Fort Richardson held annual hunts. The...muskrat (Ondatra zibethicus), porcupine (Erethizon dorsatum), red squirrel (Tamiasciurus hudsonicus), snowshoe hare, river otter (Lutra canadensis

FUZZY LOGIC BASED INTELLIGENT CONTROL OF A VARIABLE SPEED CAGE MACHINE WIND GENERATION SYSTEM

Science.gov (United States)

The paper describes a variable-speed wind generation system where fuzzy logic principles are used to optimize efficiency and enhance performance control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which either pump...

75 FR 1073 - Holla Bend National Wildlife Refuge, Pope and Yell Counties, AR

Science.gov (United States)

2010-01-08

... mandated activities for protection of federally listed species. Control of nuisance wildlife populations... and gun, with the exception of a small tract adjacent to the Levee Trail. Turkeys, rabbits, squirrels... aggressive control measures initiated. Habitat management would include converting 125 acres from...

Advanced induction machine model in phase coordinates for wind turbine applications

DEFF Research Database (Denmark)

Fajardo, L.A.; Iov, F.; Hansen, Anca Daniela

2007-01-01

In this paper an advanced phase coordinates squirrel cage induction machine model with time varying electrical parameters affected by magnetic saturation and rotor deep bar effects, is presented. The model uses standard data sheet for characterization of the electrical parameters, it is developed...

Dynamic Stability Analysis of Autonomous Medium-Voltage Mixed-Source Microgrid

DEFF Research Database (Denmark)

Zhao, Zhuoli; Yang, Ping; Guerrero, Josep M.

2015-01-01

-space model of the autonomous MV mixed-source microgrid containing diesel generator set (DGS), grid-supporting battery energy storage system (BESS), squirrel cage induction generator (SCIG) wind turbine and network is developed. Sensitivity analysis is carried out to reveal the dynamic stability margin...

Dissimilarity of slow-wave activity enhancement by torpor and sleep deprivation in a hibernator

NARCIS (Netherlands)

Strijkstra, AM; Daan, S

1998-01-01

Sleep regulation processes have been hypothesized to be involved in function and timing of arousal episodes in hibernating ground squirrels. We investigated the importance of sleep regulation during arousal episodes by sleep deprivation experiments. After sleep deprivation of 4, 12, and 24 h,

Simple mechanical parameters identification of induction machine using voltage sensor only

International Nuclear Information System (INIS)

Horen, Yoram; Strajnikov, Pavel; Kuperman, Alon

2015-01-01

Highlights: • A simple low cost algorithm for induction motor mechanical parameters estimation is proposed. • Voltage sensing only is performed; speed sensor is not required. • The method is suitable for both wound rotor and squirrel cage motors. - Abstract: A simple low cost algorithm for induction motor mechanical parameters estimation without speed sensor is presented in this paper. Estimation is carried out by recording stator terminal voltage during natural braking and subsequent offline curve fitting. The algorithm allows accurately reconstructing mechanical time constant as well as loading torque speed dependency. Although the mathematical basis of the presented method is developed for wound rotor motors, it is shown to be suitable for squirrel cage motors as well. The algorithm is first tested by reconstruction of simulation model parameters and then by processing measurement results of several motors. Simulation and experimental results support the validity of the proposed algorithm

Molecular evolution of the cone visual pigments in the pure rod-retina of the nocturnal gecko, Gekko gekko.

Science.gov (United States)

Yokoyama, S; Blow, N S

2001-10-03

We have isolated a full-length cDNA encoding a putative ultraviolet (UV)-sensitive visual pigment of the Tokay gecko (Gekko gekko). This clone has 57 and 59% sequence similarities to the gecko RH2 and MWS pigment genes, respectively, but it shows 87% similarity to the UV pigment gene of the American chameleon (Anolis carolinensis). The evolutionary rates of amino acid replacement are significantly higher in the three gecko pigments than in the corresponding chameleon pigments. The accelerated evolutionary rates reflect not only the transition from cones to rods in the retina but also the blue-shift in the absorption spectra of the gecko pigments.

Frugivoría y dispersión de semillas de la palma Oenocarpus bataua (Arecaceae en un bosque de los Andes colombianos Frugivory and seed dispersal Oenocarpus bataua palm (Arecaceae in a forest from the Colombian Andes

Directory of Open Access Journals (Sweden)

Rosario Rojas-Robles

2012-12-01

Oenocapus bataua palm in fragments of Andean forest, determine the effective dispersers and relate the spatial distribution of palm populations with the dispersion of seeds. To this end, between August 2005-June 2006, observations of the removal of fruits from eight clusters were done, and counting of consumption of fruits beneath 78 palms with mature fruits was undertaken; focal observations of 13 individuals during 90 hours; registration of frugivory with photographic traps during 165 days/nights for a total of 195 photographs and 144 consumption events; experiments with dispersion using 751 perforated fruits/seeds attached to strings and finally, plots to determine spatial distribution all were carried out. In the study area at least five species of mammals ate, dispersed, buried (Sciurus granatensis, Microsciurus mimulus, Dasyprocta punctata y Proechimys sp., cover (Marmosa robinsoni and carried the fruits of O. bataua off to caves (Marmosa robinsoni y Proechimys sp. without damaging the seed. A 21.7% of the fruits were dispersed, 13.2 gnawed or peeled, 5.6% covered, buried and carried to caves. The average distance of removal of seeds and fruits was 3.1m although in a lesser proportion, dispersion events of >50m were recorded. The abundant production of fruits, their size and weight, their intense removal by frugivores, the short dispersion distances, the absence of large size frugivores (reduced by hunting and fragmentation, that might perform long-distance dispersion, and the increase of rodents, especially squirrels, that strongly pressure the fruit resource, generate a spatially restricted seed rain of seeds responsible for the aggregate patterns of distribution of seeds, seedlings and subsequently of juveniles and sub-adults. However the short time and high percentage of seed germination and the robustness of seeds and seedlings give O. bataua the capacity to survive in dense aggregations. Therefore, despite the limitations on dispersion, this is a dominant

Modeling, control and fault diagnosis of an isolated wind energy conversion system with a self-excited induction generator subject to electrical faults

International Nuclear Information System (INIS)

Attoui, Issam; Omeiri, Amar

2014-01-01

Highlights: • A new model of the SEIG is developed to simulate both the rotor and stator faults. • This model takes iron loss, main flux and cross flux saturation into account. • A new control strategy based on Fractional-Order Controller (FOC) is proposed. • The control strategy is developed for the control of the wind turbine speed. • An on-line diagnostic procedure based on the stator currents analysis is presented. - Abstract: In this paper, a contribution to modeling and fault diagnosis of rotor and stator faults of a Self-Excited Induction Generator (SEIG) in an Isolated Wind Energy Conversion System (IWECS) is proposed. In order to control the speed of the wind turbine, while basing on the linear model of wind turbine system about a specified operating point, a new Fractional-Order Controller (FOC) with a simple and practical design method is proposed. The FOC ensures the stability of the nonlinear system in both healthy and faulty conditions. Furthermore, in order to detect the stator and rotor faults in the squirrel-cage self-excited induction generator, an on-line fault diagnostic technique based on the spectral analysis of stator currents of the squirrel-cage SEIG by a Fast Fourier Transform (FFT) algorithm is used. Additionally, a generalized model of the squirrel-cage SEIG is developed to simulate both the rotor and stator faults taking iron loss, main flux and cross flux saturation into account. The efficiencies of generalized model, control strategy and diagnostic procedure are illustrated with simulation results

Comparison of two anisotropic layer models applied to induction motors

NARCIS (Netherlands)

Sprangers, R.L.J.; Paulides, J.J.H.; Boynov, K.O.; Waarma, J.; Lomonova, E.

2013-01-01

A general description of the Anisotropic Layer Theory, derived in the polar coordinate system, and applied to the analysis of squirrel-cage induction motors (IMs), is presented. The theory considers non-conductive layers, layer with predefined current density and layers with induced current density.

Compensation methods applied in current control schemes for large AC drive systems

DEFF Research Database (Denmark)

Rus, D. C.; Preda, N. S.; Teodorescu, Remus

2012-01-01

The paper deals with modified PI current control structures for large AC drive systems which use surface mounted permanent magnet synchronous machines or squirrel-cage induction motors supplied with voltage source inverters. In order to reduce the power losses caused by high frequency switching...

77 FR 20840 - Bogue Chitto National Wildlife Refuge, LA and MS; Final Comprehensive Conservation Plan and...

Science.gov (United States)

2012-04-06

... thorough analysis of impacts on the human environment, which we included in the draft comprehensive... Pearl River Basin. The public has the opportunity to hunt white-tailed deer, squirrel, turkey, waterfowl... of historical regimes, soil types and elevation, and the current hydrological system. Management...

Transient performances analysis of wind turbine system with induction generator including flux saturation and skin effect

DEFF Research Database (Denmark)

Li, H.; Zhao, B.; Han, L.

2010-01-01

In order to analyze correctly the effect of different models for induction generators on the transient performances of large wind power generation, Wind turbine driven squirrel cage induction generator (SCIG) models taking into account both main and leakage flux saturation and skin effect were...

Comparison of two anisotropic layer models applied to induction motors

NARCIS (Netherlands)

Sprangers, R.L.J.; Paulides, J.J.H.; Boynov, K.O.; Lomonova, E.A.; Waarma, J.

2014-01-01

A general description of the Anisotropic Layer Theory, derived in the polar coordinate system, and applied to the analysis of squirrel-cage induction motors (IMs), is presented. The theory considers non-conductive layers, layer with predefined current density and layers with induced current density.

An Archeological Overview and Management Plan for the U.S. Army Natick Research and Development Laboratories.

Science.gov (United States)

1984-06-01

following mammal species: white-tailed deer, moose, bear, chipmunk, squirrel, raccoon, porcupine , woodchuck, gopher, skunk, hare, cotton-tail rabbit...fauna, such as mammoth, mastodon, giant beaver; all presently extinct. Biomass was low Ij in the tundra so there were no large herds of these mammals

Simulation analysis of a wind farm with different aggregated models

DEFF Research Database (Denmark)

Li, H.; Wang, H.; Zhao, B.

2011-01-01

Based on a wind farm including wind turbines with squirrel cage induction generators (SCIGs), different aggregated models of a wind farm, such as a single weighted average model, a reduced-order re-scaled model, a parameter transformed model and a single weighted arithmetic model were presented, ...

Food habits of the Northern Spotted Owl (Strix occidentalis caurina) at six nest sites in Washington?s east Cascades

Science.gov (United States)

Kenneth R. Bevis; Jo Ellen Richards; Gina M. King; Eric E. Hanson

1997-01-01

This paper reports on 245 pellet samples containing 479 identified prey items collected at six Northern Spotted Owl (Strix occidentalis caurina) breeding sites in the eastern portion of its range. The majority of prey (biomass) came from four species; northern flying squirrels (Glaucomys sabrinus), bushy-tailed woodrats (...

Differential activation of murine herpesvirus 68- and Kaposi's sarcoma-associated herpesvirus-encoded ORF74 G protein-coupled receptors by human and murine chemokines

NARCIS (Netherlands)

Verzijl, D.; Fitzsimons, C.P.; Van Dijk, M.; Stewart, J.P.; Timmerman, H.; Smit, M.J.; Leurs, R.

2004-01-01

Infection of mice with murine gammaherpesvirus 68 (MHV-68) is a well-characterized small animal model for the study of gammaherpesvirus infection. MHV-68 belongs to the same herpesvirus family as herpesvirus saimiri (HVS) of New World squirrel monkeys and human herpesvirus 8 (HHV-8) (also referred

Sadhana | Indian Academy of Sciences

Indian Academy of Sciences (India)

There have been renewed interests in slip-ring induction machines due to their increasing use in both grid connected and stand-alone wind power generation schemes. Despite the squirrel cage induction generators' advantages of being brushless, low-cost, needing less maintenance and having inherent overload ...

75 FR 26986 - Notice of Intent To Prepare an Amendment to the Kobuk-Seward Peninsula Resource Management Plan...

Science.gov (United States)

2010-05-13

... Conservation Act of 1980 (ANILCA), and the BLM policies. The BLM will work collaboratively with interested...: The BLM-administered Squirrel River SRMA is located in western Alaska, approximately 30 miles... amendment and associated EA will meet the requirements of the National Environmental Policy Act of 1969...

Animal studies on Spacelab-3

Science.gov (United States)

Schatte, C.; Grindeland, R.; Callahan, P.; Berry, W.; Funk, G.; Lencki, W.

1987-01-01

The flight of two squirrel monkeys and 24 rats on Spacelab-3 was the first mission to provide hands-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferom production by spleen cells, defective release of growth hormone by somatrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythropoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity.

New xenophytes from Gran Canaria (Canary Islands, Spain, with emphasis on naturalized and (potentially invasive species

Directory of Open Access Journals (Sweden)

Verloove, F.

2013-12-01

Full Text Available Trabajos recientes de campo en Gran Canaria han facilitado el descubrimiento de nuevas localidades para plantas vasculares no nativas. Agave attenuata, Antigonon leptopus, Atriplex nummularia, Cascabela thevetia, Cenchrus echinatus, Cuscuta campestris, Diplachne fusca subsp. uninervia, Diplotaxis tenuifolia, Dysphania anthelmintica (hasta ahora confundida con D. ambrosioides, Eclipta prostrata, Euphorbia pulcherrima, Fagopyrum esculentum, Gossypium barbadense, Lablab purpureus, Lemna minuta, Opuntia leucotricha, Passiflora edulis, Pennisetum glaucum, Phaseolus acutifolius, Pluchea carolinensis, Prosopis juliflora, Salvia microphylla, Schinus terebinthifolius, Senna spectabilis, Solanum chrysotrichum, Tecoma stans, Tipuana tipu, Urochloa mutica, U. plantaginea y Washingtonia se citan por primera vez para las Islas Canarias, mientras que Alopecurus myosuroides, Amaranthus blitoides, Bothriochloa ischaemum var. songarica, Cardamine flexuosa subsp. debilis, Heliotropium curassavicum, Leonotis nepetifolia, Medicago lupulina, Parkinsonia aculeata, Physalis peruviana, Phytolacca americana y Turnera ulmifolia son nuevas para la flora de la isla de Gran Canaria. Finalmente, se confirma la presencia de Paspalum vaginatum, P. distichum y Cortaderia selloana en Gran Canaria.Trabajos recientes de campo en Gran Canaria han facilitado el descubrimiento de nuevas localidades para plantas vasculares no nativas. Agave attenuata, Antigonon leptopus, Atriplex nummularia, Cascabela thevetia, Cenchrus echinatus, Cuscuta campestris, Diplachne fusca subsp. uninervia, Diplotaxis tenuifolia, Dysphania anthelmintica (hasta ahora confundida con D. ambrosioides, Eclipta prostrata, Euphorbia pulcherrima, Fagopyrum esculentum, Gossypium barbadense, Lablab purpureus, Lemna minuta, Opuntia leucotricha, Passiflora edulis, Pennisetum glaucum, Phaseolus acutifolius, Pluchea carolinensis, Prosopis juliflora, Salvia microphylla, Schinus terebinthifolius, Senna spectabilis, Solanum

Induction Generators for Direct-Drive Wind Turbines

DEFF Research Database (Denmark)

Henriksen, Matthew Lee; Jensen, Bogi Bech

2011-01-01

This paper considers the use of a squirrel cage induction generator for a direct-drive wind turbine. Advantages of this topology include a simple/rugged construction, and no need for permanent magnets. A major focus of this paper is the choice of an appropriate pole number. An iterative, analytical...

Environmental Assessment and FONSI for the Joint United States/Republic of Korea Research and Development Study for Improved Underground Ammunition Storage Technologies Tests, Magdalena, New Mexico

Science.gov (United States)

1994-09-01

pine (Pinus edulis) on the south-facing slopes and New Mexico locust (Robina neomexicana) and scrub oak ( Quercus gambelii) on the north facing slopes...condition of the area. The disturbed area would be reseeded with a mixture of native species such as Arizona fescue (Festuca arizonica ), squirrel-tail

Archaeological Sites Inventory of the High Priority Portions of Training Areas 1, 2, 3, 4, 5, 6, 11, 13, and H of the Pinon Canyon Maneuver Site, Las Animas County, Colorado

Science.gov (United States)

2007-03-18

badger, and porcupine . Small mammals and nongame mammals found in the area are snowshoe hare, squirrel, muskrat, weasel, ringtail, shrew, mole...often buying up water sources and allowing their herds to roam across public and private land. By the early 1920s most of the public land had been

Successional dynamics and restoration implications of a montane coniferous forest in the central Appalachians, USA

Science.gov (United States)

Thomas M. Schuler; Rachel J. Collins

2002-01-01

Central Appalachian montane red spruce (Picea rubens Sarg.) communities have been greatly reduced in extent and functional quality over the past century. This community decline has put several plant and animal species, such as the endangered Virginia northern flying squirrel (Glaucomys sabrinus fuscus Shaw), at risk from habitat...

The trophic responses of two different rodent-vector-plague systems to climate change.

Science.gov (United States)

Xu, Lei; Schmid, Boris V; Liu, Jun; Si, Xiaoyan; Stenseth, Nils Chr; Zhang, Zhibin

2015-02-07

Plague, the causative agent of three devastating pandemics in history, is currently a re-emerging disease, probably due to climate change and other anthropogenic changes. Without understanding the response of plague systems to anthropogenic or climate changes in their trophic web, it is unfeasible to effectively predict years with high risks of plague outbreak, hampering our ability for effective prevention and control of the disease. Here, by using surveillance data, we apply structural equation modelling to reveal the drivers of plague prevalence in two very different rodent systems: those of the solitary Daurian ground squirrel and the social Mongolian gerbil. We show that plague prevalence in the Daurian ground squirrel is not detectably related to its trophic web, and that therefore surveillance efforts should focus on detecting plague directly in this ecosystem. On the other hand, plague in the Mongolian gerbil is strongly embedded in a complex, yet understandable trophic web of climate, vegetation, and rodent and flea densities, making the ecosystem suitable for more sophisticated low-cost surveillance practices, such as remote sensing. As for the trophic webs of the two rodent species, we find that increased vegetation is positively associated with higher temperatures and precipitation for both ecosystems. We furthermore find a positive association between vegetation and ground squirrel density, yet a negative association between vegetation and gerbil density. Our study thus shows how past surveillance records can be used to design and improve existing plague prevention and control measures, by tailoring them to individual plague foci. Such measures are indeed highly needed under present conditions with prevailing climate change. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

The trophic responses of two different rodent–vector–plague systems to climate change

Science.gov (United States)

Xu, Lei; Schmid, Boris V.; Liu, Jun; Si, Xiaoyan; Stenseth, Nils Chr.; Zhang, Zhibin

2015-01-01

Plague, the causative agent of three devastating pandemics in history, is currently a re-emerging disease, probably due to climate change and other anthropogenic changes. Without understanding the response of plague systems to anthropogenic or climate changes in their trophic web, it is unfeasible to effectively predict years with high risks of plague outbreak, hampering our ability for effective prevention and control of the disease. Here, by using surveillance data, we apply structural equation modelling to reveal the drivers of plague prevalence in two very different rodent systems: those of the solitary Daurian ground squirrel and the social Mongolian gerbil. We show that plague prevalence in the Daurian ground squirrel is not detectably related to its trophic web, and that therefore surveillance efforts should focus on detecting plague directly in this ecosystem. On the other hand, plague in the Mongolian gerbil is strongly embedded in a complex, yet understandable trophic web of climate, vegetation, and rodent and flea densities, making the ecosystem suitable for more sophisticated low-cost surveillance practices, such as remote sensing. As for the trophic webs of the two rodent species, we find that increased vegetation is positively associated with higher temperatures and precipitation for both ecosystems. We furthermore find a positive association between vegetation and ground squirrel density, yet a negative association between vegetation and gerbil density. Our study thus shows how past surveillance records can be used to design and improve existing plague prevention and control measures, by tailoring them to individual plague foci. Such measures are indeed highly needed under present conditions with prevailing climate change. PMID:25540277

Does serotonin influence aggression? Comparing regional activity before and during social interaction

DEFF Research Database (Denmark)

Summers, C.H.; Korzan, W.J.; Lukkes, J.L.

2005-01-01

Serotonin is widely believed to exert inhibitory control over aggressive behavior and intent. In addition, a number of studies of fish, reptiles, and mammals, including the lizard Anolis carolinensis, have demonstrated that serotonergic activity is stimulated by aggressive social interaction...... in both dominant and subordinate males. As serotonergic activity does not appear to inhibit agonistic behavior during combative social interaction, we investigated the possibility that the negative correlation between serotonergic activity and aggression exists before aggressive behavior begins. To do......, where low serotonergic activity may help promote aggression, agonistic behavior also stimulates the greatest rise in serotonergic activity among the most aggressive males, most likely as a result of the stress associated with social interaction....

Revisión de los Sciuridae del Aragoniense y del Rambliense en la fosa de Calatayud-Montalbán = Revision of Aragonian and Ramblian Sciuridae in the Calatayud-Montalban Trench

NARCIS (Netherlands)

Cuenca Bescós, G.

1988-01-01

The Sciuridae are the family of rodents that comprises all extant and fossil squirrels. In the Ramblian and especially in the Aragonian of the Tertiary basin of Calatayud-Montalbán (Aragón, Spain) the remains of Sciuridae are relatively abundant. A major problem solved in this paper is the

Food habits of Northern Goshawks nesting in south central Wyoming

Science.gov (United States)

John R. Squires

2000-01-01

Northern Goshawks (Accipiter gentiles) nesting in south central Wyoming consumed at least 33 species of prey; 14 were mammals and 19 were birds. Based on percent occurrence in regurgitated pellets, dominant (>10% frequency) prey species included: red squirrel (Tamiasciurus hudsonicus; present in 50% of pellets), Northern Flicker (Colaptes auratus; 34...

Food habits of nesting prairie falcons in Campbell County

Science.gov (United States)

John R. Squires; Stanley H. Anderson; Robert Oakleaf

1989-01-01

Fifteen species of prey were utilized by nesting Prairie Falcons (Falco mexicanus) as determined through pellet analysis. Thirteen-lined Ground Squirrels (Spermophilus tridecemlineatus), the most common prey, were present in 91% of the pellets, followed by Western Meadowlarks (Sturnella neglecta) which were present in 56% of pellets. Horned Larks (Eremophila...

Muscle Moment Arms and Sensitivity Analysis of a Mouse Hindlimb Musculoskeletal Model

Science.gov (United States)

2016-05-12

musculature in squirrels, rats, and guinea pigs with con- trast-enhanced microCT. Anat Rec (Hoboken) 294, 915–928. Deisseroth K (2011) Optogenetics. Nat...downhill running in mdx mice. Muscle Nerve 43, 878–886. Medler S (2002) Comparative trends in shortening velocity and force production in skeletal muscles

Reproduction, Embryonic Development, and Maternal Transfer of Contaminants in the Amphibian Gastrophryne carolinensis

OpenAIRE

Hopkins, William Alexander; DuRant, Sarah Elizabeth; Staub, Brandon Patrick; Rowe, Christopher Lee; Jackson, Brian Phillip

2005-01-01

Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. Despite the severe effects of maternal transfer of contaminants on early development in other vertebrate lineages, no studies have examined the effects of maternal transfer of contaminants on reproduction or dev...

Effects of Load and Speed Variations in a Modified Closed Loop V/F ...

African Journals Online (AJOL)

This paper investigates the eects of load and reference speed variations in a modied closed loopv=f induction motor drive. A modied approach, involving the addition of a low frequency boostvoltage, is developed and adopted as an enhancement to the conventional closed loop v=f speedcontrol of a three phase squirrel ...

Recent records of megalopae of the crab Varuna litterata· (Fabr ...

African Journals Online (AJOL)

BERTRAM, B.C.R. 1975. Social factors influencing reproduction in wild lions. J. Zool., Lond. In: 463-482. BALFOUR, O. 1983. Infanticide in the Columbian ground squirrel, Spermophilus columbian us. Anim. BehtTV. 31: 949-950. HAMILTON, W.O. 1964. The genetical evolution of social behaviour. J. Theor. Bioi. 7: 1 - 52.

78 FR 14022 - Endangered and Threatened Wildlife and Plants; Reinstatement of Removal of the Virginia Northern...

Science.gov (United States)

2013-03-04

... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 17 [Docket No. FWS-R5-ES-2013...; Reinstatement of Removal of the Virginia Northern Flying Squirrel From the List of Endangered and Threatened Wildlife AGENCY: Fish and Wildlife Service, Interior. ACTION: Final rule. SUMMARY: We, the U.S. Fish and...

76 FR 35349 - Endangered and Threatened Wildlife and Plants; Reinstatement of Listing Protections for the...

Science.gov (United States)

2011-06-17

... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 17 [Docket No. FWS-R5-ES-2011...; Reinstatement of Listing Protections for the Virginia Northern Flying Squirrel in Compliance With a Court Order AGENCY: Fish and Wildlife Service, Interior. ACTION: Final rule. SUMMARY: We, the U.S. Fish and Wildlife...

Rotor design of a novel self-start type permanent magnet synchronous motor

OpenAIRE

Egawa, T; Higuchi, Tsuyoshi; Yokoi, Yuichi; Abe, T; Miyamoto, Yasuhiro; Ohto, M

2012-01-01

Recently, permanent magnet type synchronous motor has been used widely for industry application. In the paper, we propose a novel self-start type permanent magnet synchronous motor with squirrel-cage and analyze the basic characteristics of the motor. We try to increase the efficiency by the rotor design with the finite element analysis.

50 CFR 32.38 - Maine.

Science.gov (United States)

2010-10-01

... wild turkey, coyote (see big game) fox, raccoon, woodchuck, squirrel, porcupine, skunk, snowshoe hare... all dogs the same day you release them (see § 26.21(b) of this chapter). C. Big Game Hunting. We allow... § 32.2(i)). D. Sport Fishing. [Reserved] Moosehorn National Wildlife Refuge A. Migratory Game Bird...

76 FR 62213 - Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Mohave...

Science.gov (United States)

2011-10-06

... now used for agriculture and livestock grazing, suitable habitat still remains and may be connected to... squirrel has also been found in some areas used for agriculture (Gustafson 1993, pp. ix, 81; BLM 1998, p. 1... escape temperature and humidity extremes and predators, and to give birth (Aardahl and Roush 1985, p. 23...

Report by CF(Teritoreal), Pune, Dec 2008

Indian Academy of Sciences (India)

Least distance of the project area from the boundary of Bhimashankar Wildlife Sanctuary is approx. 3.5 km. This is not likely to affect the PA as the key-species of Bhimashankar Wildlife Sanctuary is Giant Squirrel which is restricted to the sanctuary area only. There is no contiguous forest area, vegetation joining the ...

Using maximum entropy modeling to identify and prioritize red spruce forest habitat in West Virginia

Science.gov (United States)

Nathan R. Beane; James S. Rentch; Thomas M. Schuler

2013-01-01

Red spruce forests in West Virginia are found in island-like distributions at high elevations and provide essential habitat for the endangered Cheat Mountain salamander and the recently delisted Virginia northern flying squirrel. Therefore, it is important to identify restoration priorities of red spruce forests. Maximum entropy modeling was used to identify areas of...

77 FR 4973 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition to List the San...

Science.gov (United States)

2012-02-01

... flying squirrel's coloration is gray to wood-brown to cinnamon on the upper side of the body and pale.... 5). Microhabitat factors related to mature forests (such as stumps, snags, and dead trees) are used... the amount of fuel in the forest include removing dead trees and thinning the forest (USFS 2005b, p...

50 CFR 32.62 - Tennessee.

Science.gov (United States)

2010-10-01

... hunting for raccoon and opossum from legal sunset to legal sunrise. C. Big Game Hunting. We allow hunting... do not open for spring squirrel hunting. C. Big Game Hunting. We allow the hunting of white-tailed... hours for raccoon and opossum are legal sunset to legal sunrise. C. Big Game Hunting. We allow hunting...

50 CFR 32.68 - West Virginia.

Science.gov (United States)

2010-10-01

... between March 1 and the youth squirrel season in September. C. Big Game Hunting. We allow the hunting of... enter the refuge on foot. You may use hand-powered, two-wheeled carts for transporting big game. 3. You... big game hunting, we only allow ammunition containing a single lead projectile. We prohibit the use of...

50 CFR 32.48 - New Hampshire.

Science.gov (United States)

2010-10-01

... launching areas outside the refuge. B. Upland Game Hunting. [Reserved] C. Big Game Hunting. We allow hunting.... We allow hunting of coyote (see C. Big Game Hunting), fox, raccoon, woodchuck, squirrel, porcupine... must pick up all dogs the same day you release them (see § 26.21(b) of this chapter). C. Big Game...

Making Connections. A Curriculum and Activity Guide to Mammoth Cave National Park. [Grades] K-3.

Science.gov (United States)

National Park Service (Dept. of Interior), Washington, DC.

Kentucky's Mammoth Cave National Park is important because of its diversity of life on the surface and underground. Some of the plants in the park include trees such as oaks, hickories, tulip poplars, sycamores, and many types of bushes. The animal population is also very diverse and includes bats, squirrels, deer, raccoons, opossums, chipmunks,…

New radiobiological findings bearing on the 1977 ICRP recommendations. [Sensitivity of mouse and monkey prenatal oocytes to chronic, low-dose, tritium exposure

Energy Technology Data Exchange (ETDEWEB)

Dobson, R.L.

1979-02-14

Recent experiments on low-level irradiation during development raise questions relevant to ICRP Publication 26. Mice and monkeys were studied; the measured endpoint was the radiation-induced loss of female germ cells. Three issues are examined. The first is the numerical value of Q (quality factor) appropriate for low-energy beta rays. Comparisons of tritium with gamma radiation were made under conditions of chronic, low-level exposure, and the relative biological effectiveness (RBE) was found to approach 3. Its bearing on ICRP's recommendations concerning Q applicable to tritium is discussed. Second, female germ cells in squirrel monkeys before birth were discovered to be extraordinarily radiosensitive, more easily destroyed than those of mice. If this holds for other primates too, it has radiation-protection implications hitherto overlooked. Third, the contrast between massive germ-cell loss from chronic exposure in prenatal squirrel monkeys and reported radioresistance of oocytes to acute exposure in rhesus monkeys, unless due to species difference, suggests that during development protracted irradiation may be especially injurious. This also could have important radiation-protection implications and is under investigation. (ERB)

New radiobiological findings bearing on the 1977 ICRP recommendations

International Nuclear Information System (INIS)

Dobson, R.L.

1979-01-01

Recent experiments on low-level irradiation during development raise questions relevant to ICRP Publication 26. Mice and monkeys were studied; the measured endpoint was the radiation-induced loss of female germ cells. Three issues are examined. The first is the numerical value of Q (quality factor) appropriate for low-energy beta rays. Comparisons of tritium with gamma radiation were made under conditions of chronic, low-level exposure, and the relative biological effectiveness (RBE) was found to approach 3. Its bearing on ICRP's recommendations concerning Q applicable to tritium is discussed. Second, female germ cells in squirrel monkeys before birth were discovered to be extraordinarily radiosensitive, more easily destroyed than those of mice. If this holds for other primates too, it has radiation-protection implications hitherto overlooked. Third, the contrast between massive germ-cell loss from chronic exposure in prenatal squirrel monkeys and reported radioresistance of oocytes to acute exposure in rhesus monkeys, unless due to species difference, suggests that during development protracted irradiation may be especially injurious. This also could have important radiation-protection implications and is under investigation

Powassan Virus: Persistence of Virus Activity During 1966

Science.gov (United States)

McLean, Donald M.; Cobb, Cathron; Gooderham, Susan E.; Smart, Carol A.; Wilson, A. G.; Wilson, W. E.

1967-01-01

Powassan virus isolations were achieved from three of 60 pools of Ixodes cookei ticks removed from 286 groundhogs (Marmota monax) which were collected some 200 miles north of Toronto between May 5 and September 5, 1966. Virus yields per pool of one to 11 ticks ranged from 102.5 to 106.0 TCD50 for primary swine kidney tissue cultures, and positive pools were collected on June 24, July 15 and August 10. Powassan neutralizing antibodies were detected by mouse inoculation tests in 143 of 362 animals including 127 of 286 groundhogs, 14 of 45 red squirrels (Tamiasciurus hudsonicus) and two of 31 other forest mammals. The monthly prevalence of antibody in the current season's groundhogs increased from 0 to 25% with the progression of summer, but in older animals the incidence remained between 38 and 62% throughout the season. These results substantiate earlier findings which pointed towards the maintenance of Powassan virus in nature by a cycle involving groundhogs and squirrels as reservoirs, with ticks as vectors, from which human infections occurred tangentially. PMID:6019677

The French A.E.C. nuclear robotic program

International Nuclear Information System (INIS)

Foult, T.

1991-01-01

The new French nuclear robotic program launched by the CEA was started at the beginning of 1988 for the duration of two years and with the total subsidy of about 130 million French franc. This program includes the following four steps: the definition of model missions dedicated to inspection and intervention in nuclear environment, the system analysis to define the systems, functions and specifications required to perform these model missions, the technological development required to achieve these systems, and the design of demonstration models with the partial integration of the above developments. The whole program including these four steps is called SYROCO (modular SYstem for RObots COoperating in radioactive environment). The repair of leak in a pipe in a reprocessing cell, the model mission in a PWR nuclear power plant, autonomous load bearing mobile robots, squirrel concept light modular carrier concept, radiation hardening, mechanic, perception of environment, communication, control and simulation and the demonstration models are described. SHERPA project, perception management, force controlled manipulator, squirrel project, light modular carrier, processes and NAB model mission simulation are particularly mentioned

[Morphology of some tricostrongilinae (Strongylida) from the National Helminth Collection, Institute of Biology, UNAM, Mexico].

Science.gov (United States)

Falcón-Ordaz, Jorge; García-Prieto, Luis

2004-06-01

The present study analyses the taxonomic status of eleven species of trichostrongylins that parasitize rodents and lagomorphs deposited in the Colección Nacional de Helmintos, Instituto de Biología. UNAM. Mexico. This analysis is based on the morphology of the synlophe, characteristic that had not been studied for most of these nematode species and at present, it has a very important taxonomic value. As a result of this study, the identity of five species is ratified (Trichostrongylus calcaratus, Obeliscoides cuniculi, Carolinensis huehuetlana. Stilestrongylus peromysci and Nippostrongylus brasiliensis), the transference suggested previously for two more (Vexillata convoluta and Vexillata vexillata) is confirmed, Trichostrongylus chiapensis is synonymized with Boehmiella willsoni, and finally Lamothiella romerolagi is re-determined as Teporingonema cerropeladoensis and Stilestrongylus atlatilpinensis as Stilestrongylus hidalguensis.

Influence of primary prey on home-range size and habitat-use patterns of northern spotted owls (Strix occidentalis caurina)

Science.gov (United States)

Cynthia J. Zabel; Kevin S. McKelvey; James P. Ward

1995-01-01

Correlations between the home-range size of northern spotted owls (Strix occidentalis caurina) and proportion of their range in old-growth forest have been reported, but there are few data on the relationship between their home-range size and prey. The primary prey of spotted owls are wood rats and northern flying squirrels (Glaucomys sabrinus). Wood...

Test Area C-80 Complex Final Range Environmental Assessment, Revision 1

Science.gov (United States)

2009-08-14

to intense noise might contribute to the development and aggravation of stress -related conditions such as high blood pressure, coronary disease...produced by test and training missions and their associated expendables. Noise may directly inconvenience and/or stress humans and some wildlife...Sherman’s fox squirrel Sciuris niger shermani Phragmites Phragmites australis American alligator Alligator mississippiensis White cedar Chamaecyparis

Final Environmental Assessment: Implementation of the Natural Resources Management Program Clear Air Force Station, Alaska

Science.gov (United States)

2003-06-01

vison ), muskrat (Ondatra zibethicus), short-tail weasels ( Mustela erminea), red squirrels (Tamiasciurus hudsonicus), spruce grouse (Dendragapus...Intense or long-lasting smoke caused by large uncontrolled fire can impact air quality and seriously affect respiratory health • Destruction of valuable...canadensis), sharp-tailed grouse (Tympanuchus phasianellus), and least weasels ( Mustela nivalis). In addition to the large mammals and fur-bearers

Homeostasis in primates in hyperacceleration fields

Science.gov (United States)

Fuller, C. A.

1984-01-01

Various homeostatic responses of a nonhuman primate, the squirrel monkey (Saimiri sciureus) to acute changes in the acceleration environment were examined. When these animals were exposed to a hyperdynamic field the body temperature was consistently depressed and the animals showed behavioral indications of increased drowsiness. Further, time of day played a significant role in influencing these responses.

PowerPoint Presentation

Indian Academy of Sciences (India)

TOPOGRAPHY OF KARNATAKA · SOUTHERN PLATEAU · Slide 13 · Slide 14 · WESTERN GHATS · Slide 16 · Slide 17 · LARGE SQUIRRELS · Slide 19 · OPEN PLAINS · Slide 21 · Slide 22 · SLOTH BEAR · Slide 24 · Slide 25 · QUESTION: HOW DO THE SYMPATRIC SPECIES COEXIST? SYMPATRIC SPECIES · Slide 28.

Vertebrate Pest Control. Sale Publication 4077.

Science.gov (United States)

Stimmann, M. W.; Clark, Dell O.

This guide gives descriptions of common vertebrate pests and guidelines for using some common pesticides. The pests discussed are rats, mice, bats, moles, muskrats, ground squirrels, and gophers. Information is given for each pest on the type of damage the pest can do, the habitat and biology of the pest, and the most effective control methods.…

Near UV radiation effect on the lens and retina

International Nuclear Information System (INIS)

Zigman, S.

1987-01-01

The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

pisces: pomadasyidae

African Journals Online (AJOL)

PomadDsys commeT6onni (Lace~e 1802), the spotted grunter, occurs in the warmer water of the stoma) zumpti sp.n., a parasite of small carnivores and squirrels in Southern Africa (Ixodoidea: Ixodidae). J. Parasit. 60: 188-197. LEDGER, J A 1976. The arthropod parasites of vertebrates in Africa south of the Sahara (Ethio-.

Computer-Aided Teaching Using MATLAB/Simulink for Enhancing an IM Course With Laboratory Tests

Science.gov (United States)

Bentounsi, A.; Djeghloud, H.; Benalla, H.; Birem, T.; Amiar, H.

2011-01-01

This paper describes an automatic procedure using MATLAB software to plot the circle diagram for two induction motors (IMs), with wound and squirrel-cage rotors, from no-load and blocked-rotor tests. The advantage of this approach is that it avoids the need for a direct load test in predetermining the IM characteristics under reduced power.…

50 CFR 32.33 - Indiana.

Science.gov (United States)

2010-10-01

... carry a compass while hunting on the refuge. C. Big Game Hunting. We allow hunting of white-tailed deer.... 4. We prohibit quail, squirrel, and rabbit hunting during refuge deer hunts. C. Big Game Hunting. We... at all times (see § 26.21(b) of this chapter). C. Big Game Hunting. We allow hunting of white-tailed...

Mamíferos terrestres de la Reserva de la Biosfera de Sian Ka’an, Quintana Roo, México

Directory of Open Access Journals (Sweden)

Carmen Pozo de la Tijera

1999-06-01

Full Text Available Con base en el muestreo de siete localidades y una extensa revisión bibliográfica, se obtuvo la lista de especies de mamíferos terrestres de la Reserva de la Biosfera de Sian Ka’an estado de Quintana Roo, México. Durante 57 días de campo, se utilizaron trampas Sherman, Tomahawk, redes de niebla y escopetas, se registraron rastros y observaciones directas. Se registraron 70 especies, ocho órdenes, 22 familias y 57 géneros. Se encontraron seis especies como nuevos registros: Marmosa mexicana, Micronycteris microtis, Micronycteris schmidtorum, Eptesicus furinalis, Rhogeessa parvula y Ototylomys phyllotis. Doce especies son catalogadas bajo algún riesgo ecológico según la Norma Oficial Mexicana; trece especies son endémicas a Mesoamérica y una endémica de México. Se presentan cuadros de abundancia relativa, registro por localidades y por tipo de vegetación de cada especie.Based on sampling at seven localities and an extensive bibliographic research, we present a species list of terrestrial mammals of the Sian Ka’an Biosphere Reserve, Quintana Roo, Mexico. During 57 days of fieldwork we used Sherman and Tomahawk traps, mist nets, rifles, collected data of trails and made direct observations. We recorded 70 species, eight orders, 22 families, and 57 genera. Six new records are added: Marmosa mexicana, Micronycteris microtis, Micronycteris schmidtorum, Eptesicus furinalis, Rhogeessa parvula, and Ototylomys phyllotis. Twelve species are listed as threatened following the Official Mexican Norm: Tamandua mexicana, Micronycteris brachyotis, Lonchorhina aurita, Alouatta pigra, Ateles geoffroyi, Herpailurus yagouaroundi, Leopardus pardalis, Leopardus wiedii, Panthera onca, Eira barbara, Potos flavus and Tapirus bairdii. Thirteen species are endemic to Mesoamerica: M. mexicana, T. mexicana, Mormoops megalophylla, Tonatia evotis, Bauerus dubiaquercus, A. pigra, A. geoffroyi, T. bairdii, Sciurus deppei, Sciurus yucatanensis, Heteromys gaumeri

Methods for Collecting, Detecting and Identifying Biological Agents in Environmental and Animal Samples (Briefing Charts)

Science.gov (United States)

2009-09-10

Lymphomas of a Patient with AIDS ROBERT C. BOHANNON,12 LAWRENCE A. DONEHOWER,1 AND RICHARD J. FORD2* Division of Molecular Virology, Baylor College of...pressure on primate visual systems. These models, along with evidence from paleobiogeography, neuroscience , ecology, behavior, and immunology, suggest...endogenous virus) than a platyrrhine type D retrovirus (squirrel monkey retrovirus)( Andersen et al., 1979). Endogenous viruses are often

Natural regeneration of whitebark pine: Factors affecting seedling density

Science.gov (United States)

S. Goeking; D. Izlar

2014-01-01

Whitebark pine (Pinus albicaulis) is an ecologically important species in high-altitude areas of the western United States and Canada due to the habitat and food source it provides for Clark’s nutcrackers, red squirrels, grizzly bears, and other animals. Whitebark pine stands have recently experienced high mortality due to wildfire, white pine blister rust, and a...

Test Area B-75 Final Range Environmental Assessment (REA), Revision 1

Science.gov (United States)

2010-08-01

impacts to Eglin ecosystems. Some of the main invasive non-native species of concern are Chinese tallow, cogon grass , Japanese climbing fern...lotor Saw Grass Cladium jamaicensis Florida Black Bear Ursus americanus floridanus Cattail Typha domingensis Sherman’s Fox Squirrel Sciuris niger...Cont’d Yellow Indian Grass Sorghastrum nutans Flycatchers Tyrannidae spp. Purple Lovegrass Eragrostis spectabilis Cotton Mouse Peromyscus gossypinus

How to teach quantum physics to your dog

CERN Document Server

Orzel, Chad

2010-01-01

In this international bestseller, Orzel explains the key theories of quantum physics, taking his dog Emmy's anarchic behaviour as a starting point. Could she use quantum tunnelling to get through the neighbour's fence? How about diffracting round a tree to chase squirrels? From quarks and gluons to Heisenberg's uncertainty principle, this is a uniquely entertaining way to unlock the secrets of the universe.

Final Environmental Assessment for Stormwater Drainage Project on F. E. Warren Air Force Base, Wyoming

Science.gov (United States)

2005-05-01

Taxidea taxus), raccoon (Procyon lotor hirtus), porcupine (Erethizon dorsatum), red fox (Vulpes vulpes), coyote (Canus latrans), and Wyoming ground...squirrel (Spermophilus elegans). A relatively large herd of pronghorn antelope inhabits the base. Although the pronghorn on the installation are a...part of the larger Iron Mountain herd , most reside on the installation year-round. The Storm Water Drainage Project, Draft Environmental Assessment

Selection on female behaviour fluctuates with offspring environment.

Science.gov (United States)

Taylor, R W; Boutin, S; Humphries, M M; McAdam, A G

2014-11-01

Temporal variation in selection has long been proposed as a mechanism by which genetic variation could be maintained despite short-term strong directional selection and has been invoked to explain the maintenance of consistent individual differences in behaviour. We tested the hypothesis that ecological changes through time lead to fluctuating selection, which could promote the maintenance of variation in female behavioural traits in a wild population of North American red squirrels. As predicted, linear selection gradients on female aggression and activity significantly fluctuated across years depending on the level of competition among juveniles for vacant territories. This selection acted primarily through juvenile overwinter survival rather than maternal fecundity. Incorporating uncertainty in individual measures of behaviour reduced the magnitude of annual selection gradients and increased uncertainty in these estimates, but did not affect the overall pattern of temporal fluctuations in natural selection that coincided with the intensity of competition for vacant territories. These temporal fluctuations in selection might, therefore, promote the maintenance of heritable individual differences in behaviour in this wild red squirrel population. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Diagnóstico de problemas de asimetrías rotóricas en un motor de inducción de gran potencia.

Directory of Open Access Journals (Sweden)

N. Soto Salvá

2007-05-01

Full Text Available Este diagnóstico se ha realizado en un total de 14 motores de inducción, todos ellos de jaula de ardilla y de 6 000 voltios. Se hará referencia al último diagnóstico realizado que se trata de un motor de una bomba de agua de alimentar caldera tipo 4A3M-2500/6000 CT4 de una unidad generadora de electricidad de 100 MW. Mediante las técnicas de diagnóstico empleadas se logró determinar roturas de barras en la jaula de ardilla del rotor del motor.This diagnosis has been carried out in a total of 14 induction motors, all them of squirrel cage and of 6 000 volts. Reference will be made to the last carried out diagnosis that it is a motor of a bomb of water of feeding boiler type 4A3M-2500/6000 CT4 of a generating unit of electricity of 100 MW. By means of the techniques of diagnosis employees it was possible to determine breaks of bars in the cage of squirrel of the rotor in the motor.

Louisiana Coastal Area, Louisiana. Freshwater Diversion to Barataria and Breton Sound Basins. Feasibility Study. Volume 2. Technical Appendixes A, B, C, and D.

Science.gov (United States)

1984-09-01

the bullfrog, pig frog, bronze frop, leopard frog, lesser siren, gulf coast toad, preen and squirrel treefrogs, cricket frog, and several species of...geese that winter in significant numbers are lesser snow geese. Other game birds include coots, rails, gallinules, snipe, woodcock, and mourning doves...98 • . - . . . ." . . . . - " - -. - . . Simoneaux, L.F. 1979. The distribution of menhaden, genus Brevortia. with respect to salinity, in the upper

Cellular Basis for Learning Impairment in Fragile X Syndrome

Science.gov (United States)

2014-08-01

advances in therapy for neurological conditions such as stroke and epilepsy. KEY WORDS: Arctic ground squirrel, Cetacean, Hypoxia, Naked mole-rat...including migration and hibernation. Oxygen levels also vary widely, with animals adapted to sea level, high-altitude, underground and aquatic habitats...adapted for life in specific ecological niches as well as inform advances in therapy for neurological conditions such as stroke and epilepsy. Down for

On a new Flying Squirrel from Deli, Sumatra

NARCIS (Netherlands)

Jentink, F.A.

1890-01-01

Sciuropterus setosus, collected by Horner in the neighborhood of Padang (Sumatra) and described by Temminck in the »Fauna japonica”, seems to be such an extremely rare animal, that the type-specimen — an adult female — is the only individual hitherto observed by collectors and naturalists. Mr.

Infanticide in tree squirrels - a male reproductive strategy?

African Journals Online (AJOL)

1986-07-25

Jul 25, 1986 ... ... of such behaviour. The interpretation of infant killing as a sexually selected male reproductive ... stones of the sexual selection hypothesis of infanticide. The ... of genetically based strain differences in the occurrence of infanticide in ... Aggression plays a prominent role in social behaviour, with both males.

The historical and recent distribution and status of mammals in Portugal

Directory of Open Access Journals (Sweden)

Margarida Santos-Reis

1996-12-01

Full Text Available Abstract Historical and recent data on Portuguese mammals are presented in this paper, occurring on the mainland and/or in the Azores and Madeira Atlantic islands. Nowadays, 95 species of mammals are known in Portugal, of which only one (Nyctalus azoreum is an endemic species and three others (Pipistrellus maderensis, Microtus cabrerae and Lynx pardina are exclusive for Portugal and Spain. Moreover, two other species, Mustela vison and Sciurus vulgaris are recent records for the Portuguese fauna, the first due to an accidental introduction and the second resulting from a recolonization by Spanish populations. Of the remaining species, around 50% (46 species are threatened in different degrees, 34.8% (16 species being considered endangered or vulnerable. Mammals extinct in Portugal are the Gerês goat (Capra pyrenaica lusitanica and the bear (Ursus arctos.

Uso dello spazio da parte dello scoiattolo comune (Sciurus vulgaris in bosco di conifere

Directory of Open Access Journals (Sweden)

M. Adamo

2003-10-01

Full Text Available Nell?ambito di un progetto di ricerca sull?ecologia dello scoiattolo comune in boschi di conifere delle Alpi, abbiamo avviato uno studio con la radiotelemetria per indagare i fattori che influiscono sull?uso dello spazio da parte degli animali. I risultati riportati nel presente lavoro si riferiscono a due anni successivi caratterizzati da una diversa disponibilità alimentare. L?area di studio si trovava nel Parco Nazionale del Gran Paradiso, in Val di Rhemes, all?interno di una pecceta subalpina (Picea abies 85%, Larix decidua 11%, alberi morti 4%. La produzione energetica del bosco (semi delle conifere è stata valutata moltiplicando il n. di piante per ettaro x il n. medio di coni prodotti (contati su 60 alberi campione x il n. medio di semi per cono x il peso medio dei semi, trasformando poi la biomassa in Mj. Le catture sono state effettuate tre volte l?anno nel 2001 e 2002 con 30 trappole incruente Tomahawk tipo 201. Diciotto scoiattoli nel 2001 e 13 nel 2002 sono stati dotati di radiocollare (PD-2C Holohil Systems Ltd. e seguiti in estate e autunno. Sono stati calcolati i seguenti parametri: home range MCP 100%, MCP 95% (animali con singole escursioni, 100% Cluster-based (animali che usavano differenti aree di attività; stime delle core-area mono e multinucleari effettuate con la tecnica della Cluster Analysis 85%; sovrapposizione delle core-area. Nel 2001, all?inizio dell?estate, 4 maschi su 8 e 7 femmine su 8 sono emigrati nella valle adiacente o a quote più basse. Nel 2002, tutti gli individui sono rimasti residenti. La dimensione media degli home range stagionali nel 2001 è stata di 83,30 ± 48,72 ha (n = 30 contro 31,04 ± 16,65 ha (n = 19 nel 2002, la media delle core-area è stata 18,18 ± 17,74 ha nel 2001 e 9,36 ± 5,40 ha in 2002 (Kruskal-Wallis ANOVA: home range H = 22,6; g.l. = 1, P < 0,0001; core-area H = 4,55, g.l. = 1, P = 0,033. La sovrapposizione delle core-area maschio/femmina e femmina/maschio è stata maggiore nel 2001 rispetto al 2002. Nel 2001 e nell?estate del 2002 le core-area femmina/femmina sono risultate fortemente sovrapposte, mentre nell?autunno 2002 le femmine presentavano core-area esclusive. L?elevata dimensione degli home range e la grande sovrapposizione delle core-area riscontrata nel 2001, suggeriscono che si sia verificata un?alterazione dell?organizzazione sociale tipica della specie e dei consueti pattern d?uso dello spazio. Normalmente nello scoiattolo comune le femmine difendono core-area esclusivi da altre femmine adulte; i maschi adulti hanno home-range più estesi, con core-area che si sovrappongono in maniera maggiore rispetto a quelli delle femmine. In periodi di carenza di cibo anche gli adulti possono lasciare i loro home range, risultando meno stabili. A Rhemes gli scoiattoli hanno mostrato nel 2001 un comportamento simile, seppur più accentuato. È probabile che, a seguito di una bassa produttività del bosco nel 2000, gli animali nel 2001 avessero consumato gran parte del cibo a disposizione. I grandi spostamenti e l?elevata sovrapposizione degli home range erano probabilmente dovuti alla ricerca di aree con residui di semi e altre risorse trofiche, aree in cui gli animali concentravano la loro attività.

Brain calcium - Role in temperature regulation.

Science.gov (United States)

Hanegan, J. L.; Williams, B. A.

1973-01-01

Perfusion of the preoptic-anterior hypothalamus with excess calcium ion in ground squirrels produces a drop in core temperature. The magnitude of the drop is directly dependent on ambient temperature. Respiration, heart rate, and oxygen consumption are also reduced during perfusion of calcium ion. It is concluded that the depression of body temperature during calcium ion perfusion is due to generalized depression of the neurons of the preoptic-anterior hypothalamus.

Flood Control at Grafton, North Dakota, Park River.

Science.gov (United States)

1975-08-01

expected to occur, in the escarpment forest include mice, shrews , voles, bats, rabbits, squirrels, muskrat, woodchuck, beaver, pocket gopher, ground...although short-grass prairie would probably eventually be invaded by either taller tame grasses, such as brome, or taller native grasses). 2. The ...grass prairie would eventually be invaded by either taller tame grasses (brome) or taller natives in this area. Thus, the statement that "there would

Abstract Reference List: Reviews of Pertinent Literature in Shock. Volume I.

Science.gov (United States)

1981-05-18

AND HEMORRHAGE. JP Dujardin, DN Stone, LT Paul, HP Pieper. Am J. Physiol. 238(6):H902-11908 (1980) .... ........ 25 60. EFFECT OF SHIGELLA FLENERI...Postgraduate Med. J. 50:55-59 (1974) ......... ...................... 34 85. CC]MPARATIVE TOXICITY OF NETILMICIN AND GENFAMICIN IN SQUIRREl. MONKEYS ...in earlier work from our lab. 60. Effect of Shigella flexneri Endotoxin on Ureagenesis and Liver Ultrastructure in Rabbits. M. Yoshino. Exp. iol. Path

Cultural Resource Survey for the Consolidated Space Operations Center Project Near Colorado Springs, El Paso County, Colorado.

Science.gov (United States)

1982-01-01

fauna, to attract hunters prehistorically. I But as this area was not prime habitable land for humans, it probably also did not support large herds ...Rocky Mountain areas. The Archaic people were less dependent on herd movement, thus their socio-economic systems changed. This adaptation to a changing...coyotes, skunks, ground squirrels, pocket gophers, wolves, mule deer, white- tail deer, beaver, and porcupine (Larsen 1981; Goodlng 1977:4; Eddy 1981:7

Partial characterization of new adenoviruses found in lizards.

Science.gov (United States)

Ball, Inna; Behncke, Helge; Schmidt, Volker; Geflügel, F T A; Papp, Tibor; Stöhr, Anke C; Marschang, Rachel E

2014-06-01

In the years 2011-2012, a consensus nested polymerase chain reaction was used for the detection of adenovirus (AdV) infection in reptiles. During this screening, three new AdVs were detected. One of these viruses was detected in three lizards from a group of green striped tree dragons (Japalura splendida). Another was detected in a green anole (Anolis carolinensis). A third virus was detected in a Jackson's chameleon (Chamaeleo jacksonii). Analysis of a portion of the DNA-dependent DNA polymerase genes of each of these viruses revealed that they all were different from one another and from all previously described reptilian AdVs. Phylogenetic analysis of the partial DNA polymerase gene sequence showed that all newly detected viruses clustered within the genus Atadenovirus. This is the first description of AdVs in these lizard species.

The auditory brainstem response in two lizard species

DEFF Research Database (Denmark)

Brittan-Powell, Elizabeth F; Christensen-Dalsgaard, Jakob; Tang, Yezhong

2010-01-01

Although lizards have highly sensitive ears, it is difficult to condition them to sound, making standard psychophysical assays of hearing sensitivity impractical. This paper describes non-invasive measurements of the auditory brainstem response (ABR) in both Tokay geckos (Gekko gecko; nocturnal...... animals, known for their loud vocalizations) and the green anole (Anolis carolinensis, diurnal, non-vocal animals). Hearing sensitivity was measured in 5 geckos and 7 anoles. The lizards were sedated with isoflurane, and ABRs were measured at levels of 1 and 3% isoflurane. The typical ABR waveform......). Above 5 kHz, however, anoles were more than 20 dB more sensitive than geckos and showed a wider range of sensitivity (1-7 kHz). Generally, thresholds from ABR audiograms were comparable to those of small birds. Best hearing sensitivity, however, extended over a larger frequency range in lizards than...

Improving interactions between animal rights groups and conservation biologists.

Science.gov (United States)

Perry, Dan; Perry, Gad

2008-02-01

Invasive species are often considered to be a major threat to biodiversity, leading conservation biologists to often recommend their complete eradication. Animal rights groups typically categorically oppose killing animals, and their opposition has brought eradication attempts of gray squirrels in northern Italy (Europe) and mute swans in Vermont to a halt. As a result native red squirrels may disappear from Europe and ecosystem-wide impacts are expected to be caused by the swan. In contrast, cooperation between managers and animal rights groups has resulted in a successful control program for feral pigs in Fort Worth, Texas (U.S.A.). The philosophical differences between animal rights and conservation biologists' views make cooperation seem unlikely, yet documented cases of cooperation have been beneficial for both groups. We recommend that managers dealing with invasive species should consult with social scientists and ethicists to gain a better understanding of the implications of some of their policy decisions. In addition, we recommend that animal rights groups do more to support alternatives to lethal control, which are often excluded by economic limitations. Prevention of arrival of invasive species via application of the precautionary principle may be an especially productive avenue for such collaboration because it fits the goals and values of both groups.

Densities of breeding birds and changes in vegetation in an alaskan boreal forest following a massive disturbance by spruce beetles

Science.gov (United States)

Matsuoka, S.M.; Handel, C.M.; Ruthrauff, D.R.

2001-01-01

We examined bird and plant communities among forest stands with different levels of spruce mortality following a large outbreak of spruce beetles (Dendroctonus rufipennis (Kirby)) in the Copper River Basin, Alaska. Spruce beetles avoided stands with black spruce (Picea mariana) and selectively killed larger diameter white spruce (Picea glauca), thereby altering forest structure and increasing the dominance of black spruce in the region. Alders (Alnus sp.) and crowberry (Empetrum nigrum) were more abundant in areas with heavy spruce mortality, possibly a response to the death of overstory spruce. Grasses and herbaceous plants did not proliferate as has been recorded following outbreaks in more coastal Alaskan forests. Two species closely tied to coniferous habitats, the tree-nesting Ruby-crowned Kinglet (Regulus calendula) and the red squirrel (Tamiasciurus hudsonicus), a major nest predator, were less abundant in forest stands with high spruce mortality than in low-mortality stands. Understory-nesting birds as a group were more abundant in forest stands with high levels of spruce mortality, although the response of individual bird species to tree mortality was variable. Birds breeding in stands with high spruce mortality likely benefited reproductively from lower squirrel densities and a greater abundance of shrubs to conceal nests from predators.

Barter Trade in North Western Siberia in the Late of 19th - Early 20th Centuries

Directory of Open Access Journals (Sweden)

Valery V. Tsys

2015-09-01

Full Text Available The article is devoted to the issue of barter trade in the North Western Siberia by the local peoples who used different fishing and hunting products such as fish and animal fur by way of cash equivalent up to the end of 19th century. Particularly, squirrel fur was a most popular hunting product used as money equivalent in trade in the 19th century. The author notes that due to the spread of the Russian population and development of railways in the second half of the 19th century the situation gradually changed. As a result, by the beginning of the 20th century natural barter was completely replaced by monetized trade with the use of bills and coins. The article describes a system of notes used by the local indigenous population to record the sums of money in trade, such as solar signs (hundreds, squares (tens, x-shaped crosses (units, vertical lines (hundredth parts of the main value. The article also indicates that during the Civil War and the transition to the NEP (New Economic Policy an abrupt rise in prices for fishing products occurred, with the following revival of barter, when squirrel fur and fish regained their roles as cost units and universal money equivalents.

Pentek concrete scabbling system: Baseline report; Greenbook (chapter)

International Nuclear Information System (INIS)

1997-01-01

The Pentek scabbling technology was tested at Florida International University (FIU) and is being evaluated as a baseline technology. This report evaluates it for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The Pentek concrete scabbling system consisted of the MOOSE, SQUIRREL-I, and SQUIRREL-III scabblers. The scabblers are designed to scarify concrete floors and slabs using cross-section, tungsten carbide tipped bits. The bits are designed to remove concrete in 318 inch increments. The bits are either 9-tooth or demolition type. The scabblers are used with a vacuum system designed to collect and filter the concrete dust and contamination that is removed from the surface. The safety and health evaluation conducted during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure was minimal, but noise exposure was significant. Further testing for each of these exposures is recommended. Because of the outdoor environment where the testing demonstration took place, results may be inaccurate. It is feasible that the dust and noise levels will be higher in an enclosed operating environment. Other areas of concern were arm-hand vibration, whole-body vibration, ergonomics, heat stress, tripping hazards, electrical hazards, machine guarding, and lockout/tagout

The Bear Facts: Implications of Whitebark Pine Loss for Yellowstone Grizzlies

OpenAIRE

Willcox, Louisa

2009-01-01

Whitebark pine is a foundation species, and barometer of the health of high elevation forests ecosystems in the West. It provides food and cover for numerous wildlife species, including the Clark’s nutcracker, crossbill, grosbeak, red squirrel and chipmunk. Whitebark pine is particularly important in the Greater Yellowstone Ecosystem (GYE), where it provides an essential food source for the imperiled Yellowstone grizzly bear. We will review the current scientific knowledge about the relations...

Anticipatory parental care: acquiring resources for offspring prior to conception.

OpenAIRE

Boutin, S; Larsen, K W; Berteaux, D

2000-01-01

Many organisms acquire and defend resources outside the breeding season and this is thought to be for immediate survival and reproductive benefits. Female red squirrels (Tamiasciurus hudsonicus) acquire traditional food cache sites up to four months prior to the presence of any physiological or behavioural cues associated with mating or offspring dependency. They subsequently relinquish these resources to one of their offspring at independence (ten months later). We experimentally show that a...

Is progression-free survival a more relevant endpoint than overall survival in first-line HR+/HER2− metastatic breast cancer?

OpenAIRE

Forsythe A; Chandiwana D; Barth J; Thabane M; Baeck J; Shor A; Tremblay G

2018-01-01

Anna Forsythe,1 David Chandiwana,2 Janina Barth,3 Marroon Thabane,4 Johan Baeck,5 Anastasiya Shor,1 Gabriel Tremblay6 1Health Technology Assessment Evidence, Purple Squirrel Economics, New York, NY, USA; 2Global Value and Access, Novartis Pharmaceutical Corporation, East Hanover, NJ, USA; 3German Market Access, Novartis Pharma GmbH, Nuremberg, Germany; 4Health Policy and Patient Access, Novartis Pharmaceuticals Incorporated, Dorval, QC, Canada; 5Global Medical Affairs (Oncology Business Unit)...

Is progression-free survival a more relevant endpoint than overall survival in first-line HR+/HER2− metastatic breast cancer?

OpenAIRE

Forsythe,Anna; Chandiwana,David; Barth,Janina; Thabane,Marroon; Baeck,Johan; Shor,Anastasiya; Tremblay,Gabriel

2018-01-01

Anna Forsythe,1 David Chandiwana,2 Janina Barth,3 Marroon Thabane,4 Johan Baeck,5 Anastasiya Shor,1 Gabriel Tremblay6 1Health Technology Assessment Evidence, Purple Squirrel Economics, New York, NY, USA; 2Global Value and Access, Novartis Pharmaceutical Corporation, East Hanover, NJ, USA; 3German Market Access, Novartis Pharma GmbH, Nuremberg, Germany; 4Health Policy and Patient Access, Novartis Pharmaceuticals Incorporated, Dorval, QC, Canada; 5Global Medical Affairs (Oncology Business Unit)...

Testing and Evaluation of Archeological Sites 32ML404 and 32ML406 in McLean County, North Dakota.

Science.gov (United States)

1978-09-01

region include aggregating ( herd ) animals as well as those that are dispersed. The most important animal to prehistoric inhabitants of the area was the...bison which is a herd animal and served as a primary faunal resource. Important fauna that do not aggregate include deer, elk, antelope and dog. Other...fauna in the area include rabbit, squirrel, prairie dog, badger, beaver, bobcat, coyote, fox, porcupine , skunk, vole, and wolf (Zimmerman et al. 1977:4

Archaeological Investigations on the East Fork of the Salmon River, Custer County, Idaho.

Science.gov (United States)

1984-01-01

coniferous environment in addition to pine marten (Martes americana), red squirrel (Tamiasciurus hudsonicus), porcupine (Erithizon dorsatum), mountain vole...can be seen in small herds throughout the East Fork valley from the Salmon River to Big Boulder Creek. Two bands of Rocky Mountain bighorn sheep...utilize the Challis Planning Unit, one on the East Fork and the other in the Birch Creek area. The East Fork herd is comprised of approximately 50-70

The Aeolian Asynchronous Generator

Directory of Open Access Journals (Sweden)

Ionel Dragomirescu

2008-10-01

Full Text Available The production of the electric energy with lower costs could be realized with the help of the aeolian electric central. In these centrals we can use the squirrel cage asynchronous generators, because these machines are the most safety in function and easy exploited. This work show the function analyzing of the asynchronous generator having on involving torque depending on the square wind speed, the air-density and on the construction of the wing spiral.

Use of the Maximum Torque Sensor to Reduce the Starting Current in the Induction Motor

Directory of Open Access Journals (Sweden)

Muchlas

2010-03-01

Full Text Available Use of the maximum torque sensor has been demonstrated able to improve the standard ramp-up technique in the induction motor circuit system. The induction motor used was of a three-phase squirrel-cage motor controlled using a microcontroller 68HC11. From the simulation done, it has been found that this innovative technique could optimize the performance of motor by introducing low stator current and low power consumption over the standard ramp-up technique.

Systematic review of health state utility values for acute myeloid leukemia

OpenAIRE

Forsythe, Anna; Brandt, Patricia S; Dolph, Mike; Patel, Sachin; Rabe, Adrian Paul J; Tremblay, Gabriel

2018-01-01

Anna Forsythe,1 Patricia S Brandt,2 Mike Dolph,1 Sachin Patel,3 Adrian Paul J Rabe,1 Gabriel Tremblay1 1Purple Squirrel Economics, New York, NY, 2Novartis Pharmaceuticals, East Hanover, NJ, USA; 3Novartis Pharmaceuticals UK Limited, Frimley, Camberley, Surrey, UK Background: Cost-utility analyses for acute myeloid leukemia (AML) require health state utility values (HSUVs) in order to calculate quality-adjusted life-years (QALYs) for each health state. Aim: This study reviewed AML-related HSU...

Architectonic subdivisions of neocortex in the tree shrew (Tupaia belangeri)

OpenAIRE

Wong, Peiyan; Kaas, Jon H.

2009-01-01

Tree shrews are small mammals that bear some semblance to squirrels, but are actually close relatives of primates. Thus, they have been extensively studied as a model for the early stages of primate evolution. In the present study, subdivisions of cortex were reconstructed from brain sections cut in the coronal, sagittal or horizontal planes, and processed for parvalbumin (PV), SMI-32 immunopositive neurofilament protein epitopes, vesicle glutamate transporter 2 (VGluT2), free ionic zinc, mye...

Metropolitan Washington Area Water Supply Study. Appendix A. Background Information & Problem Identification.

Science.gov (United States)

1983-09-01

fritlenreptorit oient ()n Tame sectdy of tfuue ar is emhourizneds of entlr Wingto lo meirpltearn rea ntswt the p io alec for hei ofeatent of ater fromthetn...squirrel, eastern chipmonk, white-footed mouse, pine vole, and short-tailed shrew . Since colonial days, the timber wolf, panther, elk, and American bison...tion; demand reduction; Cooperative Operations on the Potomac; flowby; SI4 ATITRACTY dvree oft fW d md tEwtiIfp by blck nmmbr) In response to the Water

Comparison of Ecological Impacts of Postulated Oil Spills at Selected Alaskan Locations. Volume 2, Results

Science.gov (United States)

1975-06-01

DISCUSSION TaMe 2-22 presents the results of the oil spill scenarios examined at St. Matthew Island without cleanup. 2-485 DIESEL-2 CRUDE BUNKER...include red fox, Arctic ground squirrel, lemmings, shrews , and voles. The Arctic fox, an inhabitant of both the terrestrial area and the pack ice, is... the time you ordered this report— which is only one of the hundreds of thou- sands in the NTIS information collection avail- able to you—and the

The study of transient processes in the asynchronous starting of the synchronous motor

OpenAIRE

Alexandru Bârlea; Olivian Chiver

2012-01-01

Starting synchronous motors can be achieved by several ethods: starting with an auxiliary motor launch, starting in asynchronous regim, by feeding from a variable frequency source, auto-synchronization with the network.. In our case we study the transient processes in a asynchronous regim . In this case the synchronous motor is started like a squirrel cage induction motor . To start, the synchronous motor is equipped with a starting winding cage placed in the pole pieces of polar inducers; la...

Molecular data highlight hybridization in squirrel monkeys (Saimiri, Cebidae

Directory of Open Access Journals (Sweden)

Jeferson Carneiro

Full Text Available Abstract Hybridization has been reported increasingly frequently in recent years, fueling the debate on its role in the evolutionary history of species. Some studies have shown that hybridization is very common in captive New World primates, and hybrid offspring have phenotypes and physiological responses distinct from those of the "pure" parents, due to gene introgression. Here we used the TA15 Alu insertion to investigate hybridization in the genus Saimiri. Our results indicate the hybridization of Saimiri boliviensis peruviensis with S. sciureus macrodon, and S. b. boliviensis with S. ustus. Unexpectedly, some hybrids of both S. boliviensis peruviensis and S. b. boliviensis were homozygous for the absence of the insertion, which indicates that the hybrids were fertile.

Novel X-Linked Genes Revealed by Quantitative Polymerase Chain Reaction in the Green Anole, Anolis carolinensis

Czech Academy of Sciences Publication Activity Database

Rovatsos, M.; Altmanová, M.; Johnson Pokorná, Martina; Kratochvíl, L.

2014-01-01

Roč. 4, č. 11 (2014), s. 2107-2113 ISSN 2160-1836 R&D Projects: GA ČR GAP506/10/0718 Institutional support: RVO:67985904 Keywords : gene dosage * lizard * qPCR Subject RIV: EG - Zoology Impact factor: 3.198, year: 2014

Stress amplifies sex differences in primate prefrontal profiles of gene expression.

Science.gov (United States)

Lee, Alex G; Hagenauer, Megan; Absher, Devin; Morrison, Kathleen E; Bale, Tracy L; Myers, Richard M; Watson, Stanley J; Akil, Huda; Schatzberg, Alan F; Lyons, David M

2017-11-02

Stress is a recognized risk factor for mood and anxiety disorders that occur more often in women than men. Prefrontal brain regions mediate stress coping, cognitive control, and emotion. Here, we investigate sex differences and stress effects on prefrontal cortical profiles of gene expression in squirrel monkey adults. Dorsolateral, ventrolateral, and ventromedial prefrontal cortical regions from 18 females and 12 males were collected after stress or no-stress treatment conditions. Gene expression profiles were acquired using HumanHT-12v4.0 Expression BeadChip arrays adapted for squirrel monkeys. Extensive variation between prefrontal cortical regions was discerned in the expression of numerous autosomal and sex chromosome genes. Robust sex differences were also identified across prefrontal cortical regions in the expression of mostly autosomal genes. Genes with increased expression in females compared to males were overrepresented in mitogen-activated protein kinase and neurotrophin signaling pathways. Many fewer genes with increased expression in males compared to females were discerned, and no molecular pathways were identified. Effect sizes for sex differences were greater in stress compared to no-stress conditions for ventromedial and ventrolateral prefrontal cortical regions but not dorsolateral prefrontal cortex. Stress amplifies sex differences in gene expression profiles for prefrontal cortical regions involved in stress coping and emotion regulation. Results suggest molecular targets for new treatments of stress disorders in human mental health.

[Monkey-pox, a model of emergent then reemergent disease].

Science.gov (United States)

Georges, A J; Matton, T; Courbot-Georges, M C

2004-01-01

The recent emergence of monkey pox in the United States of America highlights the problem (known for other infectious agents) of dissemination of pathogens outside their endemic area, and of subsequent global threats of variable gravity according to agents. It is a real emergency since monkey pox had been confined to Africa for several decades, where small epidemics occurred from time to time, monkey pox is a "miniature smallpox" which, in Africa, evolves on an endemic (zoonotic) mode with, as reservoirs, several species of wild rodents (mainly squirrels) and some monkey species. It can be accidentally transmitted to man then develops as epidemics, sometimes leading to death. The virus was imported in 2003 in the United States of America, via Gambia rats and wild squirrels (all African species), and infected prairie dogs (which are now in fashion as pets), then crossed the species barrier to man. In the United States of America, screening campaigns, epidemiological investigations, and subsequent treatments led to a rapid control of the epidemic, which is a model of emergent disease for this country. Therapeutic and preventive measures directly applicable to monkey pox are discussed. They can also be applied against other pox virus infections (including smallpox). The risk of criminal introduction of pox viruses is discussed since it is, more than ever, a real worldwide threat.

Trends in Wind Turbine Generator Systems

DEFF Research Database (Denmark)

Polinder, Henk; Ferreira, Jan Abraham; Jensen, Bogi Bech

2013-01-01

This paper reviews the trends in wind turbine generator systems. After discussing some important requirements and basic relations, it describes the currently used systems: the constant speed system with squirrel-cage induction generator, and the three variable speed systems with doubly fed...... induction generator (DFIG), with gearbox and fully rated converter, and direct drive (DD). Then, possible future generator systems are reviewed. Hydraulic transmissions are significantly lighter than gearboxes and enable continuously variable transmission, but their efficiency is lower. A brushless DFIG...

ANALYSIS OF INDUCTION MOTOR WITH BROKEN BARS AND CONSTANT SPEED USING CIRCUIT-FIELD COUPLED METHOD

Directory of Open Access Journals (Sweden)

N. Halem

2015-07-01

Full Text Available The paper presents the use of the two-dimensional finite element method for modeling the three-phase squirrel-cage induction motor by using circuit coupled method. In order to analyze the machine performances, the voltage source is considered. The Ansys magnetic analysis software is used for calculating the magnetic field of an induction motor having a cage fault. The experimental results prove that the proposed approach constitutes a useful tool for the study and diagnostics of induction motors.

Neuron analysis of visual perception

Science.gov (United States)

Chow, K. L.

1980-01-01

The receptive fields of single cells in the visual system of cat and squirrel monkey were studied investigating the vestibular input affecting the cells, and the cell's responses during visual discrimination learning process. The receptive field characteristics of the rabbit visual system, its normal development, its abnormal development following visual deprivation, and on the structural and functional re-organization of the visual system following neo-natal and prenatal surgery were also studied. The results of each individual part of each investigation are detailed.

Vector control of induction machines

CERN Document Server

Robyns, Benoit

2012-01-01

After a brief introduction to the main law of physics and fundamental concepts inherent in electromechanical conversion, ""Vector Control of Induction Machines"" introduces the standard mathematical models for induction machines - whichever rotor technology is used - as well as several squirrel-cage induction machine vector-control strategies. The use of causal ordering graphs allows systematization of the design stage, as well as standardization of the structure of control devices. ""Vector Control of Induction Machines"" suggests a unique approach aimed at reducing parameter sensitivity for

Study of macro and microelements in fish from the Cienfuegos Bay. Relationship with its content in sediments.

Science.gov (United States)

Peña-Icart, M; Rodrigues Pereira-Filho, E; Lopes Fialho, L; Nóbrega, J A; Alonso-Hernández, C; Bolaños-Alvarez, Y; Muñoz-Caravaca, A; Pomares-Alfonso, M S

2017-09-01

Thirteen microelements (Al, As, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Ti, V, and Zn) and four macroelements (Ca, K, Mg, and Na) were determined in the edible muscle tissue of fish in Cienfuegos Bay. Eight species, Albula vulpes, Diapterus rhombeus, Gerres cinereus, Haemulon carbonarium, Haemulon sciurus, Micropogonias furnieri, Kyphosus sectatrix, and Lutjanus cyanopterus were studied. The total concentrations and extracted concentrations using HCl were also determined in sediments. The quality of the analysis was guaranteed by validating the used analytical methods with certified reference materials of fish and sediments. The high content of macroelements confirmed the importance of fish as a valuable source of food for the local population. New information is provided on bioaccumulation of toxic elements As, Cd, Cu, Zn, and Cr in fish of the bay, with concentrations that overcame the local or international maximum allowable levels for human consumption in most samples analyzed. A high correlation between the content of toxic elements As, Cd, Zn, and macroelement K in fish and its concentration extracted from sediments using the HCl extraction method was observed.

Haliotrematoides spp. (Monogenoidea: Dactylogyridae) infecting the gills of grunts (Perciformes: Haemulidae) from the southern coast of Quintana Roo, Mexico.

Science.gov (United States)

Mendoza-Franco, Edgar F; Reyes-Lizama, C; González-Solís, D

2009-12-01

One previously described species, Haliotrema striatohamus Zhukov, 1981, found off the coast of Cuba and Campeche (Gulf of Mexico), is redescribed and transferred to Haliotrematoides Kritsky, Yang and Sun, 2009, as Haliotrematoides striatohamus ( Zhukov, 1981) n. comb. This transfer is based on the study of new specimens of this species found in the gill lamellae of grunts, i.e., Haemulon aurolineatum Cuvier, Haemulon plumierii (Lacepède), and Haemulon sciurus (Shaw) (Haemulidae), all from the southern coast of Quintana Roo, Mexico. In addition, another previously described species, Haliotrema brevispirocirrus Zhukov, 1981 from Haemulon striatum (Linnaeus) from Havana, Cuba, is also transferred to Haliotrematoides based on the comparative morphology of its original description. Data are provided for prevalence and mean intensity as well as for the morphologic and biometric variability of H. striatohamus from different hosts. The new replacement of H. striatohamus ( Zhukov, 1981) n. comb. and H. brevispirocirrus (Zhukov, 1981) n. comb. infecting these taxa represents the first known species of Haliotrematoides on these fishes and new geographical records for these dactylogyrid monogenoids.

Pranked by Audubon: Constantine S. Rafinesque's description of John James Audubon's imaginary Kentucky mammals

Science.gov (United States)

Woodman, Neal

2016-01-01

The North American naturalist Constantine S. Rafinesque spent much of the year 1818 engaged in a solo journey down the Ohio River Valley to explore parts of what was then the western United States. Along the way, he visited a number of fellow naturalists, and he spent more than a week at the Henderson, Kentucky, home of artist and ornithologist John James Audubon. During the succeeding two years, Rafinesque published descriptions of new species that resulted from his expedition, including eleven species of fishes that eventually proved to have been invented by Audubon as a prank on the credulous naturalist. Less well known are a number of “wild rats” described by Rafinesque that include one recognized species (Musculus leucopus) and ten other, imaginary “species” fabricated by Audubon (Gerbillus leonurus, G. megalops, Spalax trivittata, Cricetus fasciatus, Sorex cerulescens, S. melanotis, Musculus nigricans, Lemmus albovittatus, L. talpoides, Sciurus ruber). Rafinesque's unpublished sketches of these animals provide important insight regarding the supposed nature of the animals invented by Audubon and ultimately published by Rafinesque.

Prevalence of West Nile virus in migratory birds during spring and fall migration

Science.gov (United States)

Dusek, Robert J.; McLean, R.G.; Kramer, L.D.; Ubico, S.R.; Dupuis, A.P.; Ebel, G.D.; Guptill, S.C.

2009-01-01

To investigate the role of migratory birds in the dissemination of West Nile virus (WNV), we measured the prevalence of infectious WNV and specific WNV neutralizing antibodies in birds, principally Passeriformes, during spring and fall migrations in the Atlantic and Mississippi flyways from 2001-2003. Blood samples were obtained from 13,403 birds, representing 133 species. Specific WNV neutralizing antibody was detected in 254 resident and migratory birds, representing 39 species, and was most commonly detected in northern cardinals (Cardinalis cardinalis) (9.8%, N = 762) and gray catbirds (Dumetella carolinensis) (3.2%,N = 3188). West Nile virus viremias were detected in 19 birds, including 8 gray catbirds, and only during the fall migratory period. These results provide additional evidence that migratory birds may have been a principal agent for the spread of WNV in North America and provide data on the occurrence of WNV in a variety of bird species. Copyright ?? 2009 by The American Society of Tropical Medicine and Hygiene.

The Mechanical Transient Process at Asynchronous Motor Oscillating Mode

Science.gov (United States)

Antonovičs, Uldis; Bražis, Viesturs; Greivulis, Jānis

2009-01-01

The research object is squirrel-cage asynchronous motor connected to single-phase sinusoidal. There are shown, that by connecting to the stator windings a certain sequence of half-period positive and negative voltage, a motor rotor is rotated, but three times slower than in the three-phase mode. Changing the connecting sequence of positive and negative half-period voltage to stator windings, motor can work in various oscillating modes. It is tested experimentally. The mechanical transient processes had been researched in rotation and oscillating modes.

Estudios Mastozoológicos Colombianos, II Estudios Mastozoológicos Colombianos, II

Directory of Open Access Journals (Sweden)

Barriga Bonilla Ernesto

1966-12-01

Full Text Available This is a second contribution to the systematic and zoogeographical knowledge of the Colombian mammals. Sciurus (Guerlinguetus aestuans georgihernandezi (new subsp. is described from the vicinity of Mitú, Vaupés, at the right bank of the Vaupés River. It might be recognized by the absence of light postauricular patches, besides the upperparts are darker, and the lower ones are lighter than in S. a. gilvigularis, and the tips of the hairs in the tail are white instead of ochraceous (or xanthine orange. A specimen from the opposite bank of the Vaupés River (collected at Cubiyú Savanna is referred to S. a. gilvigularis, a taxon previously unrecorded from Colombia. However it is noteworthy that the Vaupés River acts here as a barrier between the ranges of both subspecies, but the Rio Negro, as well as other large rivers of the Brazilian Amazonian are not barriers for subspecies of S. aestuans.  The brown brocket of the Macarena Mountains is named Mazama gouazoubira medemi It is strikingly lighter than M. g. murelia, its closest geographical relative, so that it resembles M. g. cita from Northern Colombia and Venezuela, but it mainly differs in chromatic details, as well as by its larger lachrymal bone. This is a second contribution to the systematic and zoogeographical knowledge of the Colombian mammals. Sciurus (Guerlinguetus aestuans georgihernandezi (new subsp. is described from the vicinity of Mitú, Vaupés, at the right bank of the Vaupés River. It might be recognized by the absence of light postauricular patches, besides the upperparts are darker, and the lower ones are lighter than in S. a. gilvigularis, and the tips of the hairs in the tail are white instead of ochraceous (or xanthine orange. A specimen from the opposite bank of the Vaupés River (collected at Cubiyú Savanna is referred to S. a. gilvigularis, a taxon previously unrecorded from Colombia. However it is noteworthy that the Vaupés River acts here as a barrier between

Wireless Monitoring of Induction Machine Rotor Physical Variables

Directory of Open Access Journals (Sweden)

Jefferson Doolan Fernandes

2017-11-01

Full Text Available With the widespread use of electric machines, there is a growing need to extract information from the machines to improve their control systems and maintenance management. The present work shows the development of an embedded system to perform the monitoring of the rotor physical variables of a squirrel cage induction motor. The system is comprised of: a circuit to acquire desirable rotor variable(s and value(s that send it to the computer; a rectifier and power storage circuit that converts an alternating current in a continuous current but also stores energy for a certain amount of time to wait for the motor’s shutdown; and a magnetic generator that harvests energy from the rotating field to power the circuits mentioned above. The embedded system is set on the rotor of a 5 HP squirrel cage induction motor, making it difficult to power the system because it is rotating. This problem can be solved with the construction of a magnetic generator device to avoid the need of using batteries or collector rings and will send data to the computer using a wireless NRF24L01 module. For the proposed system, initial validation tests were made using a temperature sensor (DS18b20, as this variable is known as the most important when identifying the need for maintenance and control systems. Few tests have shown promising results that, with further improvements, can prove the feasibility of using sensors in the rotor.

Long-term prairie falcon population changes in relation to prey abundance, weather, land uses, and habitat conditions

Science.gov (United States)

Steenhof, Karen; Kochert, Michael N.; Carpenter, L.B.; Lehman, Robert N.

1999-01-01

We studied a nesting population of Prairie Falcons (Falco mexicanus) in the Snake River Birds of Prey National Conservation Area (NCA) from 1974-1997 to identify factors that influence abundance and reproduction. Our sampling period included two major droughts and associated crashes in Townsend's ground squirrel (Spermophilus townsendii) populations. The number of Prairie Falcon pairs found on long-term survey segments declined significantly from 1976-1997. Early declines were most severe at the eastern end of the NCA, where fires and agriculture have changed native shrubsteppe habitat. More recent declines occurred in the portion of canyon near the Orchard Training Area (OTA), where the Idaho Army National Guard conducts artillery firing and tank maneuvers. Overall Prairie Falcon reproductive rates were tied closely to annual indexes of ground squirrel abundance, but precipitation before and during the breeding season was related inversely to some measures of reproduction. Most reproductive parameters showed no significant trends over time, but during the 1990s, nesting success and productivity were lower in the stretch of canyon near the OTA than in adjacent areas. Extensive shrub loss, by itself, did not explain the pattern of declines in abundance and reproduction that we observed. Recent military training activities likely have interacted with fire and livestock grazing to create less than favorable foraging opportunities for Prairie Falcons in a large part of the NCA. To maintain Prairie Falcon populations in the NCA, managers should suppress wildfires, restore native plant communities, and regulate potentially incompatible land uses.

Wireless Monitoring of Induction Machine Rotor Physical Variables.

Science.gov (United States)

Doolan Fernandes, Jefferson; Carvalho Souza, Francisco Elvis; Cipriano Maniçoba, Glauco George; Salazar, Andrés Ortiz; de Paiva, José Alvaro

2017-11-18

With the widespread use of electric machines, there is a growing need to extract information from the machines to improve their control systems and maintenance management. The present work shows the development of an embedded system to perform the monitoring of the rotor physical variables of a squirrel cage induction motor. The system is comprised of: a circuit to acquire desirable rotor variable(s) and value(s) that send it to the computer; a rectifier and power storage circuit that converts an alternating current in a continuous current but also stores energy for a certain amount of time to wait for the motor's shutdown; and a magnetic generator that harvests energy from the rotating field to power the circuits mentioned above. The embedded system is set on the rotor of a 5 HP squirrel cage induction motor, making it difficult to power the system because it is rotating. This problem can be solved with the construction of a magnetic generator device to avoid the need of using batteries or collector rings and will send data to the computer using a wireless NRF24L01 module. For the proposed system, initial validation tests were made using a temperature sensor (DS18b20), as this variable is known as the most important when identifying the need for maintenance and control systems. Few tests have shown promising results that, with further improvements, can prove the feasibility of using sensors in the rotor.

Spatial clustering of Borrelia burgdorferi sensu lato within populations of Allen's chipmunks and dusky-footed woodrats in northwestern California.

Science.gov (United States)

Hacker, Gregory M; Brown, Richard N; Fedorova, Natalia; Girard, Yvette A; Higley, Mark; Clueit, Bernadette; Lane, Robert S

2018-01-01

The ecology of Lyme borreliosis is complex in northwestern California, with several potential reservoir hosts, tick vectors, and genospecies of Borrelia burgdorferi sensu lato. The primary objective of this study was to determine the fine-scale spatial distribution of different genospecies in four rodent species, the California ground squirrel (Otospermophilus beecheyi), northern flying squirrel (Glaucomys sabrinus), dusky-footed woodrat (Neotoma fuscipes), and Allen's chipmunk (Neotamias senex). Rodents were live-trapped between June 2004 and May 2005 at the Hoopa Valley Tribal Reservation (HVTR) in Humboldt County, California. Ear-punch biopsies obtained from each rodent were tested by polymerase chain reaction (PCR) and sequencing analysis. The programs ArcGIS and SaTScan were used to examine the spatial distribution of genospecies. Multinomial log-linear models were used to model habitat and host-specific characteristics and their effect on the presence of each borrelial genospecies. The Akaike information criterion (AICc) was used to compare models and determine model fit. Borrelia burgdorferi sensu stricto was primarily associated with chipmunks and B. bissettiae largely with woodrats. The top model included the variables "host species", "month", and "elevation" (weight = 0.84). Spatial clustering of B. bissettiae was detected in the northwestern section of the HVTR, whereas B. burgdorferi sensu stricto was clustered in the southeastern section. We conclude that the spatial distribution of these borreliae are driven at least in part by host species, time-of-year, and elevation.

Small mammals of a bitterbrush-cheatgrass community

International Nuclear Information System (INIS)

Gano, K.A.; Rickard, W.H.

1982-01-01

Small mammals were live-trapped in burned and unburned segments of a bitterbrush-cheatgrass community during the years 1974-1979. Results indicate that the shrub-dominated unburned area supports about three times as many small mammals as the cheatgrass-dominated burned area. Species composition was similar in both areas with the exception of one ground squirrel (Spermophilus townsendii) captured on the unburned area. Other species caught were the Great Basin pocket mouse (Perognathus parvus), deer mouse (Peromyscus maniculatus), northern grasshopper mouse (Onychomys leucogaster), and the western harvest mouse (Reithrodontomys megalotis)

Vector control of three-phase AC machines system development in the practice

CERN Document Server

Quang, Nguyen Phung; Dittrich, J

2015-01-01

This book addresses the vector control of three-phase AC machines, in particular induction motors with squirrel-cage rotors (IM), permanent magnet synchronous motors (PMSM) and doubly-fed induction machines (DFIM), from a practical design and development perspective. The main focus is on the application of IM and PMSM in electrical drive systems, where field-orientated control has been successfully established in practice. It also discusses the use of grid-voltage oriented control of DFIMs in wind power plants. This second, enlarged edition includes new insights into flatness-based  nonlinear

Performance characteristic of saturable three-phase interface transformers-investigations using a model simulation

Energy Technology Data Exchange (ETDEWEB)

Gierse, G; Pestka, J

1981-11-01

For electric locomotive drives equipped with converter fed squirrel cage induction motors the influence of different three-phase interface transformers on the smoothing of the motor currents is shown. In combination with a modified pulse-width-controlled thyristor firing system the size of the interface transformers can be greatly reduced without the distortion currents being greater than in the case of reactors in the motor supply lines. Finally, it is shown how the additional magnetic coupling of two driving systems can influence the behaviour of the two motors.

Sensorless soft starters for loaded induction motors

Energy Technology Data Exchange (ETDEWEB)

Chrisanov, V.I.; Konovalov, Y.N. [Power Plearonics Department, State University of Telecommunication, St. Petersburg (Russian Federation)

1997-12-31

The paper is devoted to the research and design of sensorless thyristor soft starters for loaded induction motors (IM) with short circuited squirrel case rotors. It is shown that the applied direct converter topology depends on the output power and consists of a small number of thyristors with special algorithm of switching to realize voltage - frequency control of IM drive systems at low speeds of starting. Sensorless control is realized from the both sides when neither direct converter nor drive system consists of any additional transducers for soft starting operation. (orig.) 4 refs.

Improvement the DTC system for electric vehicles induction motors

Directory of Open Access Journals (Sweden)

Arif Ali

2010-01-01

Full Text Available A three-phase squirrel-cage induction motor is used as a propulsion system of an electric vehicle (EV. Two different control methods have been designed. The first is based on the conventional DTC Scheme adapted for three level inverter. The second is based on the application of fuzzy logic controller to the DTC scheme. The motor is controlled at different operating conditions using a FLC based DTC technique. In the simulation the novel proposed technique reduces the torque and current ripples. The EV dynamics are taken into account.

Conflicting research on the demography, ecology, and social behavior of Gunnison's prairie dogs (Cynomys gunnisoni)

Science.gov (United States)

Hoogland, John L.; Cully, Jack F.; Rayor, Linda S.; Fitzgerald, James P.

2012-01-01

Gunnison's prairie dogs (Cynomys gunnisoni) are rare, diurnal, colonial, burrowing, ground-dwelling squirrels. Studies of marked individuals living under natural conditions in the 1970s, 1980s, and 1990s showed that males are heavier than females throughout the year; that adult females living in the same territory are consistently close kin; and that females usually mate with the sexually mature male(s) living in the home territory. Research from 2007 through 2010 challenges all 3 of these findings. Here we discuss how different methods might have led to the discrepancies.

Assessment of the Possibility to Use Hybrid Electromechanical Transmission in Combat Tracked Platforms

Directory of Open Access Journals (Sweden)

Glebov V.V.

2017-05-01

Full Text Available The article gives an estimation of possible using the hybrid electromechanical transmission performed as a series circuit in tracked vehicle of 50-tonnes weight category using the series-manufactured components of hybrid electric drive system. As components of electric drive (motor-generators and traction electric motors it is invited to use AC induction motors with squirrel-cage rotor, that has no moving contacts and can work both in motor and generator modes, and energy storage buffer is made on the basis of consecutively connected Lithium-ion batteries.

Investigation of Sylvatic Typhus at a Wilderness Camp

Centers for Disease Control (CDC) Podcasts

In this podcast, Dr. Greg Dasch discusses an outbreak of four cases of sylvatic typhus that occurred at a wilderness camp in Pennsylvania. Sylvatic typhus is very rare in the United States, with only 41 cases since it was discovered in the United States in 1975. Lab work at CDC and the discovery that all four camp counselors who became ill had slept in the same bunk at the camp between 2004 and 2006 ultimately led to confirmation that flying squirrels living in the wall of the cabin were to blame for the illnesses.

power generation and control of a self excited squirrel cage

African Journals Online (AJOL)

HOD

as an induction motor whose electrical performance has been ... induction motor to supply the reactive power requirement for power ... residual magnetic flux in the rotor magnetic field until ..... renewable energy conversion source Ola-22.pdf].

The common iliac artery in the ground squirrel (Citellus citellus

Directory of Open Access Journals (Sweden)

Blagojević M.

2013-01-01

Full Text Available The common iliac arteries (a. iliaca communis dextra et a. iliaca communis sinistra are the terminal branches of the abdominal aorta. The paired external iliac artery (a. iliaca externa dextra et a. iliaca externa sinistra is a stronger branch of the paired common iliac artery. Before they leave the abdominal cavity and continue as the femoral arteries (a. femoralis dextra et a. femoralis sinistra each external iliac artery forms the following branches: 1. The internal pudendal artery (a. pudenda interna which, with its branches, supplies the tensor fasciae latae and quadriceps muscles (a. circumflexa femoris lateralis, cranial region of the urinary bladder, cranial end of the uterine horn in females, the deferent duct and tail of the epididymis in males (a. umbilicalis the rectum, the external anal sphincter and perineum (a. rectalis caudalis with blood. 2. The obturator artery (a. obturatoria, which supplies both of the obturator muscles, as well as the proximal end of the adductor muscle. 3. The pudendoepigastric trunk (truncus pudendoepigastricus is a short vessel, which with its branches (a. pudenda externa, a. epigastrica caudalis et a. urethrogenitalis supplies the caudal end of the rectus abdominis muscle, tip of the penis, preputium, superficial inguinal lymph nodes, scrotum in males and inguinal mamma in females, transversus and internus abdominis muscles, neck of the urinary bladder, urethra, vagina and vulva in females and accessory glands in males. 4. Paired internal iliac arteries (a. iliaca interna dextra et a. iliaca interna sinistra are thinner branches than the external iliac arteries. The internal iliac artery with its branches supplies the cranial and caudal parts of the gluteal muscles (a. glutea cranialis et a. glutea caudalis, as well as the muscles of the lateral side of the tail (a. caudalis lateralis. [Projekat Ministarstva nauke Republike Srbije, br. 143018

Lower Paleozoic carbonate rocks of Baird Mountains Quadrangle, Alaska

Energy Technology Data Exchange (ETDEWEB)

Dumoulin, J.A.; Harris, A.G.

1985-04-01

Lower Paleozoic carbonate rocks in the Baird Mountains quadrangle form a relatively thin (about 550 m), chiefly shallow-water succession that has been imbricately thrust and metamorphosed to lower greenschist facies. Middle and Upper Cambrian rocks - the first reported from the western Brooks Range - occur in the northeastern quarter of the quadrangle, south of Angayukaqsraq (formerly Hub) Mountain. They consist of marble grading upward into thin-bedded marble/dolostone couplets and contain pelagiellid mollusks, acetretid brachiopods, and agnostid trilobites. Sedimentologic features and the Pelagiellas indicate a shallow-water depositional environment. Overlying these rocks are Lower and Middle Ordovician marble and phyllite containing graptolites and conodonts of midshelf to basinal aspect. Upper Ordovician rocks in this area are bioturbated to laminated dolostone containing warm, shallow-water conodonts. In the Omar and Squirrel Rivers areas to the west, the Lower Ordovician carbonate rocks show striking differences in lithofacies, biofacies, and thickness. Here they are mainly dolostone with locally well-developed fenestral fabric and evaporite molds, and bioturbated to laminated orange- and gray-weathering dolomitic marble. Upper Silurian dolostone, found near Angayukaqsraq Mountain and on the central Squirrel River, contains locally abundant corals and stronmatoporoids. Devonian carbonate rocks are widely distributed in the Baird Mountains quadrangle; at least two distinct sequences have been identified. In the Omar area, Lower and Middle Devonian dolostone and marble are locally cherty and rich in megafossils. In the north-central (Nakolik River) area, Middle and Upper Devonian marble is interlayered with planar to cross-laminated quartz-carbonate metasandstone and phyllite.

USING OF OBJECT-ORIENTED DESIGN PRINCIPLES IN ELECTRIC MACHINES DEVELOPMENT

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N.N. Zablodskii

2016-03-01

Full Text Available Purpose. To develop the theoretical basis of electrical machines object-oriented design, mathematical models and software to improve their design synthesis, analysis and optimization. Methodology. We have applied object-oriented design theory in electric machines optimal design and mathematical modelling of electromagnetic transients and electromagnetic field distribution. We have correlated the simulated results with the experimental data obtained by means of the double-stator screw dryer with an external solid rotor, brushless turbo-generator exciter and induction motor with squirrel cage rotor. Results. We have developed object-oriented design methodology, transient mathematical modelling and electromagnetic field equations templates for cylindrical electrical machines, improved and remade Cartesian product and genetic optimization algorithms. This allows to develop electrical machines classifications models, included not only structure development but also parallel synthesis of mathematical models and design software, to improve electric machines efficiency and technical performance. Originality. For the first time, we have applied a new way of design and modelling of electrical machines, which is based on the basic concepts of the object-oriented analysis. For the first time is suggested to use a single class template for structural and system organization of electrical machines, invariant to their specific variety. Practical value. We have manufactured screw dryer for coil dust drying and mixing based on the performed object-oriented theory. We have developed object-oriented software for design and optimization of induction motor with squirrel cage rotor of AIR series and brushless turbo-generator exciter. The experimental studies have confirmed the adequacy of the developed object-oriented design methodology.

Anatomical distribution of estrogen target neurons in turtle brain

International Nuclear Information System (INIS)

Kim, Y.S.; Stumpf, W.E.; Sar, M.

1981-01-01

Autoradiographic studies with [ 3 H]estradiol-17β in red-eared turtle (Pseudemys scripta elegans) show concentration and retention of radioactivity in nuclei of neurons in certain regions. Accumulations of estrogen target neurons exist in the periventricular brain with relationships to ventral extensions of the forebrain ventricles, including parolfactory, amygdaloid, septal, preoptic, hypothalamic and thalamic areas, as well as the dorsal ventricular ridge, the piriform cortex, and midbrain-pontine periaqueductal structures. The general anatomical pattern of distribution of estrogen target neurons corresponds to those observed not only in another reptile (Anolis carolinensis), but also in birds and mammals, as well as in teleosts and cyclostomes. In Pseudemys, which appears to display an intermediate degree of phylogenetic differentiation, the amygdaloid-septal-preoptic groups of estrogen target neurons constitute a continuum. In phylogenetic ascendency, e.g. in mammals, these cell populations are increasingly separated and distinct, while in phylogenetic descendency, e.g. in teleosts and cyclostomes, an amygdaloid group appears to be absent or contained within the septal-preoptic target cell population. (Auth.)

Anatomical distribution of estrogen target neurons in turtle brain

Energy Technology Data Exchange (ETDEWEB)

Kim, Y.S.; Stumpf, W.E.; Sar, M. (North Carolina Univ., Chapel Hill (USA))

1981-12-28

Autoradiographic studies with (/sup 3/H)estradiol-17..beta.. in red-eared turtle (Pseudemys scripta elegans) show concentration and retention of radioactivity in nuclei of neurons in certain regions. Accumulations of estrogen target neurons exist in the periventricular brain with relationships to ventral extensions of the forebrain ventricles, including parolfactory, amygdaloid, septal, preoptic, hypothalamic and thalamic areas, as well as the dorsal ventricular ridge, the piriform cortex, and midbrain-pontine periaqueductal structures. The general anatomical pattern of distribution of estrogen target neurons corresponds to those observed not only in another reptile (Anolis carolinensis), but also in birds and mammals, as well as in teleosts and cyclostomes. In Pseudemys, which appears to display an intermediate degree of phylogenetic differentiation, the amygdaloid-septal-preoptic groups of estrogen target neurons constitute a continuum. In phylogenetic ascendency, e.g. in mammals, these cell populations are increasingly separated and distinct, while in phylogenetic descendency, e.g. in teleosts and cyclostomes, an amygdaloid group appears to be absent or contained within the septal-preoptic target cell population.

DESIGN METHODOLOGY OF SELF-EXCITED ASYNCHRONOUS GENERATOR

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Berzan V.

2012-04-01

Full Text Available The paper sets out the methodology of designing an asynchronous generator with capacitive self-excitation. It is known that its design is possible on the basis of serial synchronous motor with squirrel cage rotor. With this approach, the design reworked only the stator winding of electrical machines, making it cost-effectively implement the creation of the generator. Therefore, the methodology for the design, optimization calculations, the development scheme and the stator winding excitation system gain, not only of practical interest, and may also be useful for specialists in the field of electrical machines in the design of asynchronous generators.

Preliminary assessment of the tradeoffs between the electric motor and the transmission in electric vehicles

Science.gov (United States)

Levi, E.

1983-01-01

The efficiency, weight, and cost of various propulsion system for 4-passenger electric vehicles are compared. These systems comprise the electric motor and the required speed reducing transmission to obtain the appropriate speed at the wheel. Three types of motors, dc synchronous, and squirrel-cage were considered at 6000 ycm and 24 000 rpm for a peak power of 40 kW. Two types of gearing selected were a single speed differential and a differential with a differential with a 4-speed gearbox. Only components that were readily realizable within present state-of-the-art were considered.

Voltage and frequency control of wind-powered islanded microgrids based on induction generator and STATCOM

DEFF Research Database (Denmark)

Bouzid, Allal; Sicard, Pierre; Guerrero, Josep M.

2015-01-01

This paper presents a comprehensive modeling of a three-phase cage induction machine used as a self-excited squirrel-cage induction generator (SEIG), and discusses the regulation of the voltage and frequency of a self-excited SEIG based on the action of the static synchronous Compensator (STATCOM......). The STATCOM with the proposed controller consists of a three-phase voltage-sourced inverter and a DC voltage. The compensator can provide the active and reactive powers and regulate AC system bus voltage and the frequency, but also may enhance the load stability. Moreover, a feed forward control method...

Consumption of seeds of southwestern white pine (Pinus strobiformis) by Black Bear (Ursus americanus)

Science.gov (United States)

Mattson, David J.; Arundel, Terry A.

2013-01-01

We report a discovery of black bears (Ursus americanus) consuming seeds of southwestern white pine (Pinus strobiformis) on north slopes of the San Francisco Peaks near Flagstaff, Arizona, in high-elevation, mixed-species conifer forest. In one instance, a bear had obtained seeds from cones excavated from a larder horde made by a red squirrel (Tamiasciurus hudsonicus). Consumption of seeds of southwestern white pine by bears had not been previously documented. This discovery adds to the number of species of pine used by bears for food as well as the geographic range within which the behavior occurs.

Carolus Linnaeus and the Edible Dormouse

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Carlo Violani

1995-05-01

Full Text Available Abstract Carolus Linnaeus was totally unacquainted with the Edible Dormouse Myoxus glis (L., a species not found in Sweden: while describing Mus Rattus in the 10th Edition of the "Systema Naturae" (1758, the Swedish naturalist confessed his ignorance concerning the "Glis" of the ancients and suggested that it might have been the marmot or the hamster. Thanks to written information received from his correspondent in Slovenia, Giovanni Antonio Scopoli, Linnaeus was able to include the new species Sciurus Glis in his 12th Edition of the "Systema Naturae" (1766, reporting almost verbatim a summary of Scopoli's description of the rodent. Scopoli's letter is still preserved in the Library of the Linnean Society of London. The Linnean type locality "Habitat in Europa australi" for the Edible Dormouse Myoxus glis glis must therefore be restricted to "Southern Carniola, Slovenia", contra "Germany" as stated, for instance, by Miller (1912, Toschi (1965, Corbet (1978 and Storch (1978. A new name is required for the continental European form, for which M. glis germanicus ssp. nov. is here proposed. Some information on the appreciation of Myoxus glis as a delicacy ("carnes avide eduntur" in Linnaeus' words conclude the paper. Riassunto Carlo Linneo ed il Ghiro - Dopo aver descritto Mus Rattus nella decima edizione del "Systema Naturae" (1758 il naturalista svedese Carlo Linneo confessava di non essere a conoscenza del "Glis" degli antichi autori e ne suggeriva l'identificazione con la Marmotta o con il Criceto comune; è infatti noto che Myoxus glis non è diffuso in Svezia. In base ad una lettera ricevuta dal suo corrispondente in Slovenia, Giovanni Antonio Scopoli, Linneo fu in grado di descrivere questa nuova specie come Sciurus Glis nella dodicesima edizione del "Systema

Evidence of Red-cockaded Woodpecker nestling displacement by southern flying squirrels

Science.gov (United States)

James R. McCormick; Richard N. Conner; Daniel Saenz; D. Brent Burt

2004-01-01

Red-cockaded Woodpeckers (Picoides borealis) are unique among woodpeckers in that they excavate their roost and nest cavities entirely within living pines (Ligon 1970). A number of secondary cavity nesters and other vertebrates are dependent on Red-cockaded Woodpeckers for the cavities they create (Rudolph et al. 1990, Loeb 1993, LaBranche and...

[Ornithine decarboxylase in mammalian organs and tissues at hibernation and artificial hypobiosis].

Science.gov (United States)

Logvinovich, O S; Aksenova, G E

2013-01-01

Ornithine decarboxylase (ODC, EC 4.1.1.17.) is a short-lived and dynamically regulated enzyme of polyamines biosynthesis. Regulation of functional, metabolic and proliferative state of organs and tissues involves the modifications of the ODC enzymatic activity. The organ-specific changes in ODC activity were revealed in organs and tissues (liver, spleen, bone marrow, kidney, and intestinal mucosa) of hibernating mammals - squirrels Spermophilus undulates - during the hibernating season. At that, a positive correlation was detected between the decline and recovery of the specialized functions of organs and tissues and the respective modifications of ODC activity during hibernation bouts. Investigation of changes in ODC activity in organs and tissues of non-hibernating mammals under artificial hypobiosis showed that in Wistar rats immediately after exposure to hypothermia-hypoxia-hypercapnia (hypobiosis) the level of ODC activity was low in thymus, spleen, small intestine mucosa, neocortex, and liver. The most marked reduction in enzyme activity was observed in actively proliferating tissues: thymus, spleen, small intestine mucosa. In bone marrow of squirrels, while in a state of torpor, as well as in thymus of rats after exposure to hypothermia-hypoxia-hypercapnia, changes in the ODC activity correlated with changes in the rate of cell proliferation (by the criterion of cells distribution over cell cycle). The results obtained, along with the critical analysis of published data, indicate that the ODC enzyme is involved in biochemical adaptation of mammals to natural and artificial hypobiosis. A decline in the ODC enzymatic activity indicates a decline in proliferative, functional, and metabolic activity of organs and tissues of mammals (bone marrow, mucosa of small intestine, thymus, spleen, neocortex, liver, kidneys) when entering the state of hypobiosis.

IMITATION MODEL OF A HIGH-SPEED INDUCTION MOTOR WITH FREQUENCY CONTROL

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V. E. Pliugin

2017-12-01

Full Text Available Purpose. To develop the imitation model of the frequency converter controlled high-speed induction motor with a squirrel-cage rotor in order to determine reasons causes electric motor vibrations and noises in starting modes. Methodology. We have applied the mathematical simulation of electromagnetic field in transient mode and imported obtained field model as an independent object in frequency converter circuit. We have correlated the simulated result with the experimental data obtained by means of the PID regulator factors. Results. We have made the simulation model of the high-speed induction motor with a squirrel-cage rotor speed control in AnsysRMxprt, Ansys Maxwell and Ansys Simplorer, approximated to their physical prototype. We have made models modifications allows to provide high-performance computing (HPC in dedicated server and computer cluster to reduce the simulation time. We have obtained motor characteristics in starting and rated modes. This allows to make recommendations on determination of high-speed electric motor optimal deign, having minimum indexes of vibrations and noises. Originality. For the first time, we have carried out the integrated research of induction motor using simultaneously simulation models both in Ansys Maxwell (2D field model and in Ansys Simplorer (transient circuit model with the control low realization for the motor soft start. For the first time the correlation between stator and rotor slots, allows to obtain minimal vibrations and noises, was defined. Practical value. We have tested manufactured high-speed motor based on the performed calculation. The experimental studies have confirmed the adequacy of the model, which allows designing such motors for new high-speed construction, and upgrade the existing ones.

Serologic evidence of Jamestown Canyon and Keystone virus infection in vertebrates of the DelMarVa Peninsula.

Science.gov (United States)

Watts, D M; LeDuc, J W; Bailey, C L; Dalrymple, J M; Gargan, T P

1982-11-01

Serological data accumulated during the past decade indicated that a variety of feral and domestic animals of the Delaware-Maryland-Virginia (DelMarVa) Peninsula were infected with Jamestown Canyon (JC) and/or Keystone (KEY) viruses (Bunyaviridae, California serogroup). Neutralizing (N) antibody to JC virus was most prevalent in white-tailed deer, sika deer, cottontail rabbits and horses. KEY virus N antibody was detected most frequently in gray squirrels and domestic goats. N antibody indicative of past infection by one or both viruses also was found in raccoons, horses and humans. JC and/or KEY virus N antibodies were not demonstrable in sera of several other species of small mammals and reptiles. Investigations were extended to evaluate the role of domestic goats as an amplifying host of JC and KEY viruses and to assess their potential as sentinels of virus transmission. Goats maintained in the Pocomoke Cypress Swamp during the summer season of 1978, acquired N antibodies to JC and KEY viruses. Following experimental inoculation with either JC or KEY virus, all goats developed N antibody despite the absence of a demonstrable viremia in most animals. Goats proved to be effective as sentinels for monitoring the transmission of JC and KEY viruses; however, the exceptionally low titers or absence of viremia following inoculation with these viruses would seem to preclude a potential virus-amplifying role for this species. Although findings implicated primarily gray squirrels and white-tailed deer as possible amplifying hosts of KEY and JC virus, respectively, further investigations will be required to clarify their role, particularly since both viruses may be maintained entirely by transovarial transmission.

Cell-poor septa separate representations of digits in the ventroposterior nucleus of the thalamus in monkeys and prosimian galagos.

Science.gov (United States)

Qi, Hui-Xin; Gharbawie, Omar A; Wong, Peiyan; Kaas, Jon H

2011-03-01

The architectonic features of the ventroposterior nucleus (VP) were visualized in coronal brain sections from two macaque monkeys, two owl monkeys, two squirrel monkeys, and three galagos that were processed for cytochrome oxidase, Nissl bodies, or the vesicular glutamate transporter 2 (vGluT2). The traditional ventroposterior medial (VPM) and ventroposterior lateral (VPL) subnuclei were easily identified, as well as the forelimb and hindlimb compartments of VPL, as they were separated by poorly staining, cell-poor septa. Septa also separated other cell groups within VPM and VPL, specifically in the medial compartment of VPL representing the hand (hand VPL). In one squirrel monkey and one galago we demonstrated that these five groups of cells represent digits 1-5 in a mediolateral sequence by injecting tracers into the cortical representation of single digits, defined by microelectrode recordings, and relating concentrations of labeled neurons to specific cell groups in hand VPL. The results establish the existence of septa that isolate the representation of the five digits in VPL of primates and demonstrate that the isolated cell groups represent digits 1-5 in a mediolateral sequence. The present results show that the septa are especially prominent in brain sections processed for vGluT2, which is expressed in the synaptic terminals of excitatory neurons in most nuclei of the brainstem and thalamus. As vGluT2 is expressed in the synaptic terminations from dorsal columns and trigeminal brainstem nuclei, the effectiveness of vGluT2 preparations in revealing septa in VP likely reflects a lack of synapses using glutamate in the septa. Copyright © 2010 Wiley-Liss, Inc.

Prioritization of skeletal muscle growth for emergence from hibernation.

Science.gov (United States)

Hindle, Allyson G; Otis, Jessica P; Epperson, L Elaine; Hornberger, Troy A; Goodman, Craig A; Carey, Hannah V; Martin, Sandra L

2015-01-15

Mammalian hibernators provide an extreme example of naturally occurring challenges to muscle homeostasis. The annual hibernation cycle is characterized by shifts between summer euthermy with tissue anabolism and accumulation of body fat reserves, and winter heterothermy with fasting and tissue catabolism. The circannual patterns of skeletal muscle remodelling must accommodate extended inactivity during winter torpor, the motor requirements of transient winter active periods, and sustained activity following spring emergence. Muscle volume in thirteen-lined ground squirrels (Ictidomys tridecemlineatus) calculated from MRI upper hindlimb images (n=6 squirrels, n=10 serial scans) declined from hibernation onset, reaching a nadir in early February. Paradoxically, mean muscle volume rose sharply after February despite ongoing hibernation, and continued total body mass decline until April. Correspondingly, the ratio of muscle volume to body mass was steady during winter atrophy (October-February) but increased (+70%) from February to May, which significantly outpaced changes in liver or kidney examined by the same method. Generally stable myocyte cross-sectional area and density indicated that muscle remodelling is well regulated in this hibernator, despite vastly altered seasonal fuel and activity levels. Body composition analysis by echo MRI showed lean tissue preservation throughout hibernation amid declining fat mass by the end of winter. Muscle protein synthesis was 66% depressed in early but not late winter compared with a summer fasted baseline, while no significant changes were observed in the heart, liver or intestine, providing evidence that could support a transition in skeletal muscle regulation between early and late winter, prior to spring emergence and re-feeding. © 2015. Published by The Company of Biologists Ltd.

Effects of prenatal ionizing irradiation on neural function and behavior

International Nuclear Information System (INIS)

Brizzee, K.R.; Ordy, J.M.; Pennwalt Corp., Rochester, NY

1986-01-01

Behavioral studies in the past decade on postnatal effects of prenatal ionizing irradiation (125-R) revealed alterations in circadian locomotor activity and modifications of duration, frequency and sequences of certain behavioral acts in irradiated rats. Other studies have shown that the effect of irradiation (150-R) and enriched environment were both significant in initial, repetitive and total error scores while at 200-R enrichment was less effective. Rats irradiated on the 13th, 14th and 15th day of gestation were born with a hopping gait, paired hind and forelimbs moving in unison. Thoracic cord section led to crossed extention hind-limb reflexes in control rats and simultaneus withdrawal of hind limbs in hopping rats, in response to pinprick. In 90 day old squirrel monkeys the percent of correct response in visual orientation, discrimination and reversal learning in 50- and 100-R offspring (Co 60 irradiation at 89-90 days gestation) were significantly lower than those of controls, and differences in reversal learning persisted undiminished at 2 years of age. Time required for body righting, head-up orientation and climbing at 45 0 incline was significantly greater in irradiated (mainly 100-R) than control animals at from 2 to 28 days of age. Visual acuity levels of 50- and 100-R 30 day old infants were significantly lower than in control infants. Stabilimeter activity in the dark was significantly higher in 50- and 100-R 30 day old infants than in controls. In the squirrel monkey studies effects of Co 60 irradiation (100-R) on postnatal development of the brain and behaviour can be identified at statistically significant levels of confidence independent of offspring nursery rearing effects. (orig.)

Trace element analysis of wild rodent tissues using the PIXE method

International Nuclear Information System (INIS)

Hill, M.W.; Mangelson, N.F.; Ryder, J.F.; Atwood, N.D.; Wood, B.W.

1980-01-01

Five species of rodents have been collected in an area near Lake Powell Utah. Common names of the five species are: Long-tailed Mouse, Small Pocket Mouse, Deer Mouse, Antelope Ground Squirrel and Kangaroo Rat. Liver, lung, kidney and hair tissues from each animal were analyzed for trace element content by proton particle-induced x-ray emission (proton PIXE) analysis. Mean concentrations for the following elements were established for the tissues of each animal type: K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb and Pb. Analyses of variance were performed on the set of elements common to all tissues. Some significant differences in element concentrations were found between animal species and between tissue types. These differences lead to the following orders based on element concentration: Long-tailed Mouse greater than or equal to Antelope Ground Squirrel greater than or equal to Kangaroo Rat greater than or equal to Small Pocket Mouse and liver greater than or equal to kidney greater than or equal to lung greater than or equal to hair. Linear regression analyses were also performed on mean elemental concentrations in tissues. These analyses lead to several conclusions. First, the pattern of trace element concentrations in each of the four tissues is the same in all five species. Second, the pattern of trace element concentrations is the same in all four tissues of one species with the exception of Ti and Fe in hair. Third, the variation of an element in the hair cannot predict the variation of that same element in the other three tissues. Only K, Ca, Ti, Mn, Fe, Cu, and Zn were included in the third study

Whole body autoradiography, ch. 13

International Nuclear Information System (INIS)

Jonkman, J.H.G.

1977-01-01

The distribution of 35 S-ringlabelled thiazinamium methylsulphate has been studied by means of whole body autoradiography in a squirrel and in mice. Accumulation of activity was found in liver, kidney and intestines (the excretion of pathways). High concentrations were also found in organs with high amount of acetylcholine receptors and in the glandular tissue. No radioactivity was seen in the central nervous system, indicating no passage through the 'blood-brain barrier'. This is the most significant difference with its tertiary analogue Prometharine hydrochloride. In pregnant mice, high concentrations were found in the placenta but only low amounts were found in liver and kidneys of the foetuses

Dual stator winding variable speed asynchronous generator: optimal design and experiments

International Nuclear Information System (INIS)

Tutelea, L N; Deaconu, S I; Popa, G N

2015-01-01

In the present paper is carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behavior in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings to optimal design using a Matlab code. Issue is limited to three phase range of double stator winding cage-induction generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA]. (paper)

HALLAZGO CASUAL DE UN PICHÓN DE Tiaris bicolor ( AV E S : THRAUPIDAE EN EL TRACTO DIGESTIVO DE UNA SERPIENTE Boa constrictor I CASUAL FINDING OF ONE CHICK OF Tiaris bicolor (AVES: THRAUPIDAE IN THE DIGESTIVE TRACT OF A Boa constrictor

Directory of Open Access Journals (Sweden)

Cristina Sainz-Borgo

2018-05-01

Full Text Available The Boa constrictor (Red-Tailed Boa is a specie that has a very diverse diet ranging from small prey such as birds, squirrels, fish and lizards to larger prey such as deer. The aim of this note was to report the casual finding of one chick of Tiaris bicolor (Black-faced Grassquit in the digestive tract of a B. constrictor that accidentally was seriously injured with a lawnmower, causing his death. One of their injuries exposed the T. bicolor chick eaten by the snake. The observation was made in a garden of a residential area located in southeast of Caracas city (Venezuela..

Investigation of Sylvatic Typhus at a Wilderness Camp

Centers for Disease Control (CDC) Podcasts

2009-06-30

In this podcast, Dr. Greg Dasch discusses an outbreak of four cases of sylvatic typhus that occurred at a wilderness camp in Pennsylvania. Sylvatic typhus is very rare in the United States, with only 41 cases since it was discovered in the United States in 1975. Lab work at CDC and the discovery that all four camp counselors who became ill had slept in the same bunk at the camp between 2004 and 2006 ultimately led to confirmation that flying squirrels living in the wall of the cabin were to blame for the illnesses.  Created: 6/30/2009 by Emerging Infectious Diseases.   Date Released: 6/30/2009.

Artificial gravity - The evolution of variable gravity research

Science.gov (United States)

Fuller, Charles A.; Sulzman, Frank M.; Keefe, J. Richard

1987-01-01

The development of a space life science research program based on the use of rotational facilities is described. In-flight and ground centrifuges can be used as artificial gravity environments to study the following: nongravitational biological factors; the effects of 0, 1, and hyper G on man; counter measures for deconditioning astronauts in weightlessness; and the development of suitable artificial gravity for long-term residence in space. The use of inertial fields as a substitute for gravity, and the relations between the radius of the centrifuge and rotation rate and specimen height and rotation radius are examined. An example of a centrifuge study involving squirrel monkeys is presented.

Energy efficiency in speed control system for induction motors; Eficiencia energetica em sistema de controle de velocidade em motores de inducao

Energy Technology Data Exchange (ETDEWEB)

Silva, Arlete Vieira da; Ribeiro, Elisangela do Nascimento; Tenorio, Iana Cavalcanti; Horta, Mario Marcos Brito [Centro Universitario de Belo Horizonte (UnBH), MG (Brazil)], e-mails: arlete.silva@prof.unibh.br, nr.elisangela@gmail.com, ianactenorio@gmail.com, mario_bhorta@yahoo.com.br

2011-07-01

This work has as objective the study of energy efficiency of induction motors fed by frequency inverters, since this is a practical resource that has progressively allowed the replacement of mechanical speed reducers. In this work the speed control of induction motors of the squirrel cage has steeped through the frequency inverters using scalar control. Induction motors are frequently used in industrial applications due to its simple construction, its low maintenance and reduced in size. It was possible through tests made at UNI-BH Electrical Engineering laboratory to obtain satisfactory results regarding the performance of the inverter CFW08 (WEG), speed control of induction motor. (author)

Utilization of an video camera in study of the goshawk (Accipiter gentilis diet

Directory of Open Access Journals (Sweden)

Martin Tomešek

2011-01-01

Full Text Available In 2009, research was carried out into the food spectrum of goshawk (Accipiter gentilis by means of automatic digital video cameras with a recoding device in the area of the Chřiby Upland. The monitoring took place at two localities in the vicinity of the village of Buchlovice at the southeastern edge of the Chřiby Upland in a period from hatching the chicks to their flying out from a nest. The unambiguous advantage of using the camera systems at the study of food spectrum is a possibility of the exact determination of brought preys in the majority of cases. As much as possible economic and effective technology prepared according to given conditions was used. Results of using automatic digital video cameras with a recoding device consist in a number of valuable data, which clarify the food spectrum of a given species. The main output of the whole project is determination of the food spectrum of goshawk (Accipiter gentilis from two localities, which showed the following composition: 89 % birds, 9.5 % mammals and 1.5 % other animals or unidentifiable components of food. Birds of the genus Turdus were the most frequent prey in both cases of monitoring. As for mammals, Sciurus vulgaris was most frequent.

Mechanisms of spectral tuning in the RH2 pigments of Tokay gecko and American chameleon

Science.gov (United States)

Takenaka, Naomi; Yokoyama, Shozo

2009-01-01

At present, molecular bases of spectral tuning in rhodopsin-like (RH2) pigments are not well understood. Here, we have constructed the RH2 pigments of nocturnal Tokay gecko (Gekko gekko) and diurnal American chameleon (Anolis carolinensis) as well as chimeras between them. The RH2 pigments of the gecko and chameleon reconstituted with 11-cis-retinal had the wavelengths of maximal absorption (λmax’s) of 467 and 496 nm, respectively. Chimeric pigment analyses indicated that 76–86%, 14–24%, and 10% of the spectral difference between them could be explained by amino acid differences in transmembrane (TM) helices I~IV, V~VII, and amino acid interactions between the two segments, respectively. Evolutionary and mutagenesis analyses revealed that the λmax’s of the gecko and chameleon pigments diverged from each other not only by S49A (serine to alanine replacement at residue 49), S49F (serine to phenylalanine), L52M (leucine to methionine), D83N (aspartic acid to asparagine), M86T (methionine to thereonine), and T97A (threonine to alanine) but also by other amino acid replacements that cause minor λmax-shifts individually. PMID:17590287

Endozoochory of seeds and invertebrates by migratory waterbirds in Oklahoma, USA

Science.gov (United States)

Green, Andy J.; Frisch, Dagmar; Michot, Thomas C.; Allain, Larry K.; Barrow, Wylie C.

2013-01-01

Given their abundance and migratory behavior, waterbirds have major potential for dispersing plants and invertebrates within North America, yet their role as vectors remains poorly understood. We investigated the numbers and types of invertebrates and seeds within freshly collected faecal samples (n = 22) of migratory dabbling ducks and shorebirds in November 2008 in two parts of Lake Texoma in southern Oklahoma. Killdeer Charadrius vociferus were transporting a higher number and diversity of both plants and invertebrates than the green-winged teal Anas carolinensis. Ten plant taxa and six invertebrate taxa were identified to at least genus level, although viability was not confirmed for most of these taxa. Bryozoan statoblasts (from four species not previously recorded from Oklahoma) were especially abundant in killdeer faeces, while the ostracod Candona simpsoni was detected as a live adult in torpor in the teal faeces. Cyperaceae and Juncaceae were the most abundant plant families represented and Cyperus strigosus seeds germinated after extraction from killdeer faeces. This snapshot study underlines the importance of waterbirds as vectors of passive dispersal of many organisms and the need for more research in this discipline.

Mechanisms of spectral tuning in the RH2 pigments of Tokay gecko and American chameleon.

Science.gov (United States)

Takenaka, Naomi; Yokoyama, Shozo

2007-09-01

At present, molecular bases of spectral tuning in rhodopsin-like (RH2) pigments are not well understood. Here, we have constructed the RH2 pigments of nocturnal Tokay gecko (Gekko gekko) and diurnal American chameleon (Anolis carolinensis) as well as chimeras between them. The RH2 pigments of the gecko and chameleon reconstituted with 11-cis-retinal had the wavelengths of maximal absorption (lambda(max)'s) of 467 and 496 nm, respectively. Chimeric pigment analyses indicated that 76-86%, 14-24%, and 10% of the spectral difference between them could be explained by amino acid differences in transmembrane (TM) helices I-IV, V-VII, and amino acid interactions between the two segments, respectively. Evolutionary and mutagenesis analyses revealed that the lambda(max)'s of the gecko and chameleon pigments diverged from each other not only by S49A (serine to alanine replacement at residue 49), S49F (serine to phenylalanine), L52M (leucine to methionine), D83N (aspartic acid to asparagine), M86T (methionine to threonine), and T97A (threonine to alanine) but also by other amino acid replacements that cause minor lambda(max)-shifts individually.

Hybrid chickadees are deficient in learning and memory.

Science.gov (United States)

McQuillan, Michael A; Roth, Timothy C; Huynh, Alex V; Rice, Amber M

2018-05-01

Identifying the phenotypes underlying postzygotic reproductive isolation is crucial for fully understanding the evolution and maintenance of species. One potential postzygotic isolating barrier that has rarely been examined is learning and memory ability in hybrids. Learning and memory are important fitness-related traits, especially in scatter-hoarding species, where accurate retrieval of hoarded food is vital for winter survival. Here, we test the hypothesis that learning and memory ability can act as a postzygotic isolating barrier by comparing these traits among two scatter-hoarding songbird species, black-capped (Poecile atricapillus) and Carolina chickadees (Poecile carolinensis), and their naturally occurring hybrids. In an outdoor aviary setting, we find that hybrid chickadees perform significantly worse on an associative learning spatial task and are worse at solving a novel problem compared to both parental species. Deficiencies in learning and memory abilities could therefore contribute to postzygotic reproductive isolation between chickadee species. Given the importance of learning and memory for fitness, our results suggest that these traits may play an important, but as yet overlooked, role in postzygotic reproductive isolation. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Insights into the Evolution of a Snake Venom Multi-Gene Family from the Genomic Organization of Echis ocellatus SVMP Genes

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Libia Sanz

2016-07-01

Full Text Available The molecular events underlying the evolution of the Snake Venom Metalloproteinase (SVMP family from an A Disintegrin And Metalloproteinase (ADAM ancestor remain poorly understood. Comparative genomics may provide decisive information to reconstruct the evolutionary history of this multi-locus toxin family. Here, we report the genomic organization of Echis ocellatus genes encoding SVMPs from the PII and PI classes. Comparisons between them and between these genes and the genomic structures of Anolis carolinensis ADAM28 and E. ocellatus PIII-SVMP EOC00089 suggest that insertions and deletions of intronic regions played key roles along the evolutionary pathway that shaped the current diversity within the multi-locus SVMP gene family. In particular, our data suggest that emergence of EOC00028-like PI-SVMP from an ancestral PII(e/d-type SVMP involved splicing site mutations that abolished both the 3′ splice AG acceptor site of intron 12* and the 5′ splice GT donor site of intron 13*, and resulted in the intronization of exon 13* and the consequent destruction of the structural integrity of the PII-SVMP characteristic disintegrin domain.

Karyotype Reorganization in the Hokou Gecko (Gekko hokouensis, Gekkonidae): The Process of Microchromosome Disappearance in Gekkota.

Science.gov (United States)

Srikulnath, Kornsorn; Uno, Yoshinobu; Nishida, Chizuko; Ota, Hidetoshi; Matsuda, Yoichi

2015-01-01

The Hokou gecko (Gekko hokouensis: Gekkonidae, Gekkota, Squamata) has the chromosome number 2n = 38, with no microchromosomes. For molecular cytogenetic characterization of the gekkotan karyotype, we constructed a cytogenetic map for G. hokouensis, which retains the ancestral karyotype of Gekkota, with 86 functional genes, and compared it with cytogenetic maps for four Toxicofera species that have many microchromosomes (Elaphe quadrivirgata, Varanus salvator macromaculatus, Leiolepis reevesii rubritaeniata, and Anolis carolinensis) and that for a lacertid species (Lacerta agilis) with only one pair of autosomal microchromosomes. Ten pairs of G. hokouensis chromosomes [GHO1, 2, 3, Z(4), 6, 7, 8, 13, 14, and 15] showed highly conserved linkage homology with macrochromosomes and/or macrochromosome arms of the four Toxicofera species and corresponded to eight L. agilis macrochromosomes (LAG). However, GHO5, GHO9, GHO10, GHO11, and LAG6 were composed of chromosome segments that have a homology with Toxicofera microchromosomes, and no homology was found in the chromosomes between G. hokouensis and L. agilis. These results suggest that repeated fusions of microchromosomes may have occurred independently in each lineage of Gekkota and Lacertidae, leading to the disappearance of microchromosomes and appearance of small-sized macrochromosomes.

Measurement of free glucocorticoids: quantifying corticosteroid-binding globulin binding affinity and its variation within and among mammalian species.

Science.gov (United States)

Delehanty, Brendan; Hossain, Sabrina; Jen, Chao Ching; Crawshaw, Graham J; Boonstra, Rudy

2015-01-01

Plasma glucocorticoids (GCs) are commonly used as measures of stress in wildlife. A great deal of evidence indicates that only free GC (GC not bound by the specific binding protein, corticosteroid-binding globulin, CBG) leaves the circulation and exerts biological effects on GC-sensitive tissues. Free hormone concentrations are difficult to measure directly, so researchers estimate free GC using two measures: the binding affinity and the binding capacity in plasma. We provide an inexpensive saturation binding method for calculating the binding affinity (equilibrium dissociation constant, K d) of CBG that can be run without specialized laboratory equipment. Given that other plasma proteins, such as albumin, also bind GCs, the method compensates for this non-specific binding. Separation of bound GC from free GC was achieved with dextran-coated charcoal. The method provides repeatable estimates (12% coefficient of variation in the red squirrel, Tamiasciurus hudsonicus), and there is little evidence of inter-individual variation in K d (range 2.0-7.3 nM for 16 Richardson's ground squirrels, Urocitellus richardsonii). The K d values of 28 mammalian species we assessed were mostly clustered around a median of 4 nM, but five species had values between 13 and 61 nM. This pattern may be distinct from birds, for which published values are more tightly distributed (1.5-5.1 nM). The charcoal separation method provides a reliable and robust method for measuring the K d in a wide range of species. It uses basic laboratory equipment to provide rapid results at very low cost. Given the importance of CBG in regulating the biological activity of GCs, this method is a useful tool for physiological ecologists.

Degree of Landscape Fragmentation Influences Genetic Isolation among Populations of a Gliding Mammal

Science.gov (United States)

Taylor, Andrea C.; Walker, Faith M.; Goldingay, Ross L.; Ball, Tina; van der Ree, Rodney

2011-01-01

Forests and woodlands are under continuing pressure from urban and agricultural development. Tree-dependent mammals that rarely venture to the ground are likely to be highly sensitive to forest fragmentation. The Australian squirrel glider (Petaurus norfolcensis) provides an excellent case study to examine genetic (functional) connectivity among populations. It has an extensive range that occurs in a wide band along the east coast. However, its forest and woodland habitat has become greatly reduced in area and is severely fragmented within the southern inland part of the species' range, where it is recognised as threatened. Within central and northern coastal regions, habitat is much more intact and we thus hypothesise that genetic connectivity will be greater in this region than in the south. To test this we employed microsatellite analysis in a molecular population biology approach. Most sampling locations in the highly modified south showed signatures of genetic isolation. In contrast, a high level of genetic connectivity was inferred among most sampled populations in the more intact habitat of the coastal region, with samples collected 1400 km apart having similar genetic cluster membership. Nonetheless, some coastal populations associated with urbanisation and agriculture are genetically isolated, suggesting the historic pattern observed in the south is emerging on the coast. Our study demonstrates that massive landscape changes following European settlement have had substantial impacts on levels of connectivity among squirrel glider populations, as predicted on the basis of the species' ecology. This suggests that landscape planning and management in the south should be focused on restoring habitat connectivity where feasible, while along the coast, existing habitat connectivity must be maintained and recent losses restored. Molecular population biology approaches provide a ready means for identifying fragmentation effects on a species at multiple scales

Degree of landscape fragmentation influences genetic isolation among populations of a gliding mammal.

Directory of Open Access Journals (Sweden)

Andrea C Taylor

Full Text Available Forests and woodlands are under continuing pressure from urban and agricultural development. Tree-dependent mammals that rarely venture to the ground are likely to be highly sensitive to forest fragmentation. The Australian squirrel glider (Petaurus norfolcensis provides an excellent case study to examine genetic (functional connectivity among populations. It has an extensive range that occurs in a wide band along the east coast. However, its forest and woodland habitat has become greatly reduced in area and is severely fragmented within the southern inland part of the species' range, where it is recognised as threatened. Within central and northern coastal regions, habitat is much more intact and we thus hypothesise that genetic connectivity will be greater in this region than in the south. To test this we employed microsatellite analysis in a molecular population biology approach. Most sampling locations in the highly modified south showed signatures of genetic isolation. In contrast, a high level of genetic connectivity was inferred among most sampled populations in the more intact habitat of the coastal region, with samples collected 1400 km apart having similar genetic cluster membership. Nonetheless, some coastal populations associated with urbanisation and agriculture are genetically isolated, suggesting the historic pattern observed in the south is emerging on the coast. Our study demonstrates that massive landscape changes following European settlement have had substantial impacts on levels of connectivity among squirrel glider populations, as predicted on the basis of the species' ecology. This suggests that landscape planning and management in the south should be focused on restoring habitat connectivity where feasible, while along the coast, existing habitat connectivity must be maintained and recent losses restored. Molecular population biology approaches provide a ready means for identifying fragmentation effects on a species at

A Novel Approach for Eccentricity Fault Detection in Squirrel Cage Induction Motors

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Mehdi Ahmadi

2013-01-01

Full Text Available In this paper, static eccentricity fault detection in induction motors is studied. Two dimensional finite element method (2D-FEM is used for faultless and eccentric condition modeling in induction motors. Also current and speed signals are compared in two experimental and simulation cases for model validating. For fault detection, fast Fourier transform is used at first. In this method, high order harmonics with small amplitude can alarms the fault occurrence. For this reason, the fault detection process is difficult.To overcome these drawbacks, it is suggested that two test coils contrive around the air-gap. So, any changes in air-gap can be detected easily. Moreover this test coils are used in open circuit case. So, these test coils do not effect on motor dynamics. Also, the results show that modulated voltage can be alarm the fault occurrence, type and percent well.

A Vertical-Axis Off-Grid Squirrel-Cage Induction Generator Wind Power System

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Peifeng Xu

2016-10-01

Full Text Available In order to broaden the limited utilization range of wind power and improve the charging and discharging control performance of the storage battery in traditional small wind power generation systems, a wind power system based on a vertical-axis off-grid induction generator is proposed in this paper. The induction generator not only can run in a wide wind speed range but can also assist the vertical-axis wind turbine to realize self-starting at low wind speed. Combined with the maximum power point tracking method, the slip frequency control strategy is employed to regulate the pulse width modulation (PWM converter to control the output power of the proposed system when the wind speed and load change. The charge and discharge of the storage battery is realized by the segmented current-limiting control strategy by means of an electric power unloader device connected to the DC bus. All these implement a balanced and stable operation of the proposed power generation system. The experimental research on the 5.5 kW prototype system is developed, and the corresponding results verify the correctness and feasibility of the system design and control strategy. Some comparison experiments with a magnetic suspension permanent magnet synchronous generator (PMSG demonstrate the application prospect of the proposed vertical-axis off-grid induction generator wind power system.

Nonphotic entrainment in a diurnal mammal, the European ground squirrel (Spermophilus citellus)

NARCIS (Netherlands)

Hut, Roelof A.; Mrosovsky, N.; Daan, Serge

1999-01-01

Entrainment by nonphotic, activity-inducing stimuli has been investigated in detail in nocturnal rodents, but little is known about nonphotic entrainment in diurnal animals. Comparative studies would offer the opportunity to distinguish between two possibilities. (1) If nonphotic phase shifts depend

Robot Deception and Squirrel Behavior: A Case Study in Bio-inspired Robotics

Science.gov (United States)

2014-08-01

soccer , and handball (Brault, Bideau, Craig, & Kkulpa, 2010; Dessing & Craig, 2010; Vignais, Kulpa, Craig, Brault, Multon, & Bideau, 2010...Robots , 1 (1), 27-52. Barnes, J. A. (1994). A pack of lies: Towards a sociology of lying. . Cambridge University press. Baron-Cohen, S. (2007). I

A blind squirrel finds a nut: tales from at an entrepreneurial adventure

Science.gov (United States)

Doughty, Chris

2010-03-01

When I received my PhD back in the dark days of 386 computers, fax machines, and a miserable economy it was commonly said that ``a degree in Physics is a great foundation for wide variety of non-academic career paths,'' but it was never entirely clear what those paths were. I still can't say what those paths are but can describe at least one: starting, building and ultimately exiting a small entrepreneurial business. This talk will describe at least one entrepreneurial path, where a physics background has value, where it is a liability, and what other skills the physicist needs to acquire to succeed in business. I will give a personal view of what it looks like inside a startup, lessons learned, mistakes made, and copious advice of dubious utility and value.

Ecological considerations for Project Wagon Wheel and hydraulic fracturing activities. Phase II(a). Annual summary report for 1974

International Nuclear Information System (INIS)

Whicker, F.W.; Alldredge, A.W.; Fisser, H.G.; Post, G.

1975-08-01

Vegetation studies were conducted to obtain data on production and biomass of shrubs and mat-forming woody plants. Tables are presented to show data for various species of plants. Aquatic studies were conducted to obtain data on benthic fauna and physical water conditions. Tables are presented to show classification of organisms per square foot of river bottom, ice thickness at water sampling locations, and stream velocities along the base of each study bluff. Mammalian studies were conducted to obtain population data on deer, mice, least chipmunk, northern grasshopper, mouse, ground squirrels, and prairie dogs. Observations were also made on antelope, moose, and mule deer. Hydraulic fracturing activities included studies on physical perturbations, vegetation documentation, and small mammal documentation

Efficient Propulsion Structure with an Axial Flux Rotary Converter for HEV Drive Unit

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Ales Havel

2011-01-01

Full Text Available This paper describes an efficient axial flux arrangement of the four quadrant rotary converter for hybrid electric vehicles. The design of the axial flux wound stator and both axial flux squirrel cage rotors is based on the arrangement of radial air gap induction motor and permanent magnet synchronous motor. The method of constant magnetic circuit volume is utilized for dimensions conversion, which results into basic dimensions of stator and rotor discs in axial flux conception. This allows the creation of real 3D models in the CAD application. Finally, the finite element simulations of electromagnetic induction in the axial flux stator pack are presented in the concluding part of this paper.

Arranque de un motor de inducción usando control difuso

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Camilo Barriga Turriago

2011-12-01

Full Text Available This paper presents the use of fuzzy logic as part of artiÞ cial intelligence in the area of power electronics and motor drivers to improve performance during the startup of an induction motor. To feed the induction motor, two circuit configurations have been chosen to use: a series of thyristors connected in ant parallel and a threephaseinverter. Control strategies such as soft start and Direct Torque Control incorporating fuzzy control have been current proposals to reduce and improve torque. The results of a simulated induction motor squirrel cage of 1.1 KW to these electronic methods show an improvement in performance at boot time, reducing power and increasingthe torque.

Control System for Producing Electricity with Dual Stator Winding Cage-Rotor Induction Generator

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Lucian Nicolae Tutelea

2014-09-01

Full Text Available This paper will present the key design equations and control design model of the Dual Stator Winding Cage-Rotor Induction Generator (DSWIG to achieve wide-speed-range operation with reduced capacity of the static power controller for low power wind or hydro applications. The proposed induction generator consists of a standard squirrel-cage rotor and a stator with two separate windings wound for a similar number of poles. Moreover, the system control strategy using the stator flux orientation is consequently proposed. The aim of the paper is to emphasize that the low speed induction generators with power electronic converters represent a realistic and useful solution for direct drive power applications.

Progressive activation of paratrigeminal nucleus during entrance to hibernation

International Nuclear Information System (INIS)

Kilduff, T.S.; Sharp, F.R.; Heller, H.C.

1988-01-01

The paratrigeminal nucleus (Pa5) undergoes a progressive increase in its uptake of 2-[ 14 C]deoxyglucose (2DG) relative to other brain structures during entrance to hibernation in the ground squirrel. This highly significant increase results in the Pa5 becoming the most highly labeled brain region during hibernation, even though it exhibits one of the lowest levels of 2DG uptake in the brain during the nonhibernating state. The progressive activation of the Pa5 observed during entrance is reversed during arousal from hibernation. These observations and the neuroanatomical projections of the Pa5 implicate this nucleus as playing a role in the entrance and maintenance of the hibernating state

A MATLAB Graphical User Interface Dedicated to the Optimal Design of the High Power Induction Motor with Heavy Starting Conditions

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Maria Brojboiu

2014-09-01

Full Text Available In this paper, a Matlab graphical user interface dedicated to the optimal design of the high power induction motor with heavy starting conditions is presented. This graphical user interface allows to input the rated parameters, the selection of the induction motor type and the optimization criterion of the induction motor design also. For the squirrel cage induction motor the graphical user interface allows the selection of the rotor bar geometry, the material of the rotor bar as well as the fastening technology of the shorting ring on the rotor bar. The Matlab graphical user interface is developed and applied to the general optimal design program of the induction motor described in [1], [2].

Economic Selection of Generators for a Wind Farm

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Omid Alavi

2015-09-01

Full Text Available The selection suitable generator for wind turbines will be done based on technical criteria and priorities of the project. In this paper, a method for determining the type of wind turbine generator with an example is explained. In the paper, for a 10kW wind turbine, two generators have been proposed. The first case is a squirrel-cage asynchronous generator coupled to the turbine through the gearbox and directly connected to three phase output. Other PM generators that are directly coupled to the turbine and it is connected to the grid using the inverter. The results show that according to wind conditions, a 10kW permanent magnet generator is more advantageous in terms of energy production.

Use of piezoelectric actuators in active vibration control of rotating machinery

Science.gov (United States)

Lin, Reng Rong; Palazzolo, Alan B.; Kascak, Albert F.; Montague, Gerald

1990-01-01

Theoretical and test results for the development of piezoelectric-actuator-based active vibration control (AVC) are presented. The evolution of this technology starts with an ideal model of the actuator and progresses to a more sophisticated model where the pushers force the squirrel cage ball bearing supports of a rotating shaft. The piezoelectric pushers consist of a stack of piezoelectric ceramic disks that are arranged on top of one another and connected in parallel electrically. This model consists of a prescribed displacement that is proportional to the input voltage and a spring that represents the stiffness of the stack of piezoelectric disks. System tests were carried out to stabilize the AVC system, verify its effectiveness in controlling vibration, and confirm the theory presented.

Field-oriented control of five-phase induction motor with open-end stator winding

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Listwan Jacek

2016-09-01

Full Text Available The mathematical model of the five-phase squirrel-cage induction motor and the system of the dual five-phase voltage source inverter have been presented. The control methods and control systems of the field-oriented control of the five-phase induction motor with an open-end stator winding are described. The structures of the direct fieldoriented control system (DFOC and the Indirect Field-oriented control system (IFOC with PI controllers in outer and inner control loops are analyzed. A method of space vector modulation used to control the system of the dual five-phase voltage source inverter has been discussed. The results of simulation studies of the field-oriented control methods are presented. Comparative analysis of the simulation results was carried out.

Dicty_cDB: Contig-U06875-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available . 44 3.6 1 ( DW405755 ) EST000176 Trichophyton rubrum cDNA library Tricho... 44 3.6 1 ( AU269367 ) Dictyostelium discoideum vegetati...5aa06.g2 hhd Oryza coarctata genomic clone ... 46 0.91 1 ( EV115075 ) 0120387 Brassica napus Root library Brassic...ES Homo sapiens cDNA 5', mRNA ... 46 0.91 1 ( CF872366 ) tric002xo14.b11 T.reesei mycelial culture...4 3.6 1 ( ES282448 ) PQ037G01.XT7 non-sporulating culture of P. brassi... 44 3.6 1 ( EL772758 ) Plate_11b_G10 Hibernati...ng 13-lined squirrel brain... 44 3.6 1 ( EC618786 ) S_F11_a1_093.ab1 Rabbit heart cDNA library Or

Dynamic characteristic of electromechanical coupling effects in motor-gear system

Science.gov (United States)

Bai, Wenyu; Qin, Datong; Wang, Yawen; Lim, Teik C.

2018-06-01

Dynamic characteristics of an electromechanical model which combines a nonlinear permeance network model (PNM) of a squirrel-cage induction motor and a coupled lateral-torsional dynamic model of a planetary geared rotor system is analyzed in this study. The simulations reveal the effects of internal excitations or parameters like machine slotting, magnetic saturation, time-varying mesh stiffness and shaft stiffness on the system dynamics. The responses of the electromechanical system with PNM motor model are compared with those responses of the system with dynamic motor model. The electromechanical coupling due to the interactions between the motor and gear system are studied. Furthermore, the frequency analysis of the electromechanical system dynamic characteristics predicts an efficient way to detect work condition of unsymmetrical voltage sag.

A Modified Load Flow Algorithm in Power Systems with Alternative Energy Sources

International Nuclear Information System (INIS)

Contreras, D.L.; Cañedo, J.M.

2017-01-01

In this paper an algorithm for calculating the steady state of electrical networks including wind and photovoltaic generation is presented. The wind generators considered are; asynchronous (squirrel cage and doubly fed) and synchronous generators using permanent magnets. The proposed algorithm is based on the formulation of nodal power injections that is solved with the modified Newton Raphson technique in its polar formulation using complex matrices notation. Each power injection of wind and photovoltaic generators is calculated independently in each iteration according to its particular mathematical model, which is generally non-linear. Results are presented with a 30-node test system. The computation time of the proposed algorithm is compared with the conventional methodology to include alternative energy sources in power flows studies. (author)