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1

Physiological crosstalk between melatonin and glucocorticoid receptor modulates T-cell mediated immune responses in a wild tropical rodent, Funambulus pennanti.  

PubMed

Immunoenhancing attributes of melatonin (Mel) on the immunocompromised state induced by glucocorticoid is well known, but the involvement of their receptors in the modulation of immunity has never been studied in any rodent. The present study explores the role of Mel and its receptors (MT1 and MT2) in amelioration of immunocompromised state induced by a synthetic glucocorticoid, dexamethasone (Dex) in a tropical rodent Funambulus pennanti. Immune parameters viz. DTH response, Lymphocyte proliferation, cytokine (IL-2) and antibody production were assessed following pretreatment of Mel and Dex alone or in combination. Mel enhanced the IL-2 production, thymic and splenic lymphocyte proliferation thereby increasing T helper cell associated immune responses and anti-KLH-IgG production. MT1 and MT2 receptor expression was downregulated following Dex treatment while glucocorticoid receptors (GR) expression was downregulated in Mel treated groups suggesting that the immunomodulatory effects of glucocorticoids and Mel are mediated via their receptors. To gain further insights on the role of Mel receptors, we used nonselective melatonin receptor antagonist luzindole which resulted in reversal of most of the immunomodulatory actions of Mel. Therefore, it may be suggested that a physiological cross talk exist between Mel and GR which is of high adaptive significance in wild animals for balancing the immunity during ecologically stressful conditions. PMID:23059469

Gupta, Sameer; Haldar, Chandana

2013-03-01

2

Photoperiodic regulation of nuclear melatonin receptor ROR? in lymphoid organs of a tropical rodent Funambulus pennanti: Role in seasonal oxidative stress.  

PubMed

The orphan nuclear receptor ROR? of RZR/ROR family has been suggested to mediate the genomic actions of melatonin on the expression of antioxidant enzymes. However, no direct evidences exist. In the present study we explored the role of photoperiod (natural and artificial) in regulation of ROR? and its association with the photoperiod induced antioxidant defense system in the lymphoid organs (spleen and thymus) of seasonally breeding, tropical squirrels, Funambulus pennanti. The photoperiod mediated regulation of antioxidant status was checked along with the ROR? expression and circulatory melatonin level in the squirrels. The enhancement of the antioxidant capacity of serum and lymphoid organ was concomitant with the short photoperiod (10L:14D) induced high levels of plasma melatonin. Further, peripheral melatonin level enhanced the AANAT activity as well as the melatonin synthesis in the lymphoid tissues. ROR? expression presented an inverse correlation with the plasma level of melatonin as well as the short day induced antioxidant enzyme activity in the lymphoid organs. The results suggest that for reduction of seasonal oxidative stress melatonin might not be utilizing the nuclear receptor ROR? pathway; rather the rise in circulatory melatonin collectively with tissue specific melatonin might be protecting the splenic and thymic lymphocytes from the seasonal oxidative stress. PMID:25541021

Gupta, Sameer; Haldar, Chandana; Ahmad, Raise

2015-01-01

3

Melatonin blocks dexamethasone-induced immunosuppression in a seasonally breeding rodent Indian palm squirrel, Funambulus pennanti  

Microsoft Academic Search

In vivo effect of dexamethasone and melatonin on immunomodulation has been investigated by studying the lymphocyte proliferation to the mitogen Con A from various lymphoid tissues including bone marrow cells of a seasonally breeding rodent adult male F. pennanti during reproductively inactive phase (October to December). During this phase, animal faces the maximum challenges of the nature (hypothermic stress, scarcity

Chandana Haldar; Seema Rai; Rajesh Singh

2004-01-01

4

Melatonin blocks dexamethasone-induced immunosuppression in a seasonally breeding rodent Indian palm squirrel, Funambulus pennanti.  

PubMed

In vivo effect of dexamethasone and melatonin on immunomodulation has been investigated by studying the lymphocyte proliferation to the mitogen Con A from various lymphoid tissues including bone marrow cells of a seasonally breeding rodent adult male F. pennanti during reproductively inactive phase (October to December). During this phase, animal faces the maximum challenges of the nature (hypothermic stress, scarcity of food and shelter). Dexamethasone treatment (60 microg/day/squirrel) for 60 consecutive days significantly decreased the thymus and spleen activity. The lymphoid tissues mass, total leukocyte, lymphocyte count of peripheral blood, bone marrow and T-cell mediated immune function was also significantly suppressed following the dexamethasone treatment but treatment of melatonin (25 microg/squirrel/day) along with dexamethasone significantly restored the suppressed immune status in squirrels. Further, histological study of the thymus showed profound changes in the cellularity with a depletion of thymocytes in the cortex region of thymic lobules and increased in connective tissues and spindle cells. Melatonin treatment alone increased thymocytes density in thymic cortex, clearly suggesting that melatonin counteracted the experimentally induced immune stress by dexamethasone. Therefore, in nature during reproductively inactive phase of the squirrel a high level of melatonin was noted, that is required to combat nature's stress, which might have increased the internal level of corticoids. PMID:15219786

Haldar, Chandana; Rai, Seema; Singh, Rajesh

2004-06-01

5

7. Rodenticides — Their Role in Rodent Pest Management in Tropical Agriculture  

Microsoft Academic Search

Rodents are serious pests of tropical agriculture. Most crops are attacked, particularly those grown for food by smallholders in the tropics. Globally, principal pest species include Sigmodon hispidus , Arvicanthis niloticus , Mastomys natalensis , Meriones spp., Bandicota spp., Rattus argentiventer and Microtus spp. Crop protection specialists usually recommend control programs based on integrated pest management (IPM) technologies involving the

Alan P. Buckle

6

UVB irradiation severely induces systemic tissue injury by augmenting oxidative load in a tropical rodent: Efficacy of melatonin as an antioxidant.  

PubMed

Tropical animals are regularly exposed to solar UV radiation. The generation and accumulation of free radicals as a result of UVB incidence causes tissue damage. In the present study we report that the irradiation of Funambulus pennanti by 1.5J/cm(2) of UVB caused significant oxidative damage to the spleen. The systemic immunity suffered collateral damage as depicted by results of total leukocyte count (TLC) while an increase in the thiobarbituric acid reactive substances (TBARS) and decline in the activities of enzymes superoxide dismutase (SOD), Glutathione peroxidase (GSH-Px) and Catalase (CAT) denoted oxidative tissue damage. Melatonin the indole-amine with known antioxidative properties when administered subcutaneously (s.c 100?g/100 gm body weight), before the UVB irradiation recovered the damages caused by UVB radiation in the spleen. The action of melatonin was direct and might have involved its membrane receptor (MT1) as well as nuclear receptor (ROR?) indicating the fact that the mode of action of melatonin in ameliorating UVB radiation induced free radical load may be receptor mediated. Our study hence reports for the first time that UVB radiation incurred oxidative damage to the spleen and suppressed the normal tissue functions. This UVB mitigated oxidative stress was recovered by the free radical scavenging and anti-apoptotic functions of melatonin when administered prior to UVB irradiation. PMID:25463654

Goswami, Soumik; Haldar, Chandana

2014-10-13

7

Effects of daily melatonin administration on circadian activity rhythms in the diurnal Indian palm squirrel (Funambulus pennanti).  

PubMed

Exogenous melatonin induces phase shifts in circadian rhythms according to a phase response curve in nocturnal rodents, several nonmammalian diurnal species, and humans. Daily administration of melatonin entrains rhythms within a narrow circadian window of sensitivity in these species. Entrainment to exogenous melatonin has not previously been demonstrated in a (nonhuman) diurnal mammal. The authors examined the effects of daily melatonin administration (via food) in the diurnal Indian palm squirrel, Funambulus pennanti. The effects of melatonin or vehicle were examined at two times of day: zeitgeber time 0 (ZT 0: light onset time) and ZT 12 (dark onset time). In addition to melatonin- and vehicle-treated squirrels, there was a third group of squirrels that received no treatment. Squirrels were held initially under 12:12 light-dark (LD) cycles, and melatonin (1 mg/kg) or vehicle was administered in food (a raisin) at either ZT 0 or ZT 12 for a total of 17 days. On the third day of treatment, constant lighting (LL) was imposed. Treatment continued at the same ZTs for a further 14 days. The number of days before free-running commenced under constant conditions was assessed for squirrels in each treatment group. Results showed that regardless of the ZT of administration, the number of days before free-running commenced was significantly greater in melatonin-treated squirrels than in vehicle-treated and untreated squirrels, and there was no difference between vehicle-treated and untreated squirrels. Although there was not a significant difference in the number of days before free-running commenced between the two times of administration, the results showed a trend for greater sensitivity to melatonin at ZT 12. This study has therefore demonstrated that the palm squirrel circadian system is entrainable to melatonin at both times of day tested, ZTs 0 and 12. This finding is in contrast to previous melatonin entrainment studies in other species, where entrainment generally occurred at only one phase, around circadian times 10 to 12. Interspecies differences in response to melatonin were discussed. PMID:9438882

Rajaratnam, S M; Redman, J R

1997-08-01

8

Long-term melatonin administration attenuates low-LET ?-radiation-induced lymphatic tissue injury during the reproductively active and inactive phases of Indian palm squirrels (Funambulus pennanti)  

PubMed Central

A comparative analysis of low linear energy transfer (LET) ?-radiation-induced damage in the lymphatic tissue of a tropical seasonal breeder, Indian palm squirrel (Funambulus pennanti), during its reproductively active phase (RAP) and inactive phase (RIP) was performed with simultaneous investigation of the effects of long-term melatonin pre-treatment (100 ?g/100 g body weight). A total of 120 squirrels (60 during RAP and 60 during RIP) were divided into 12 groups and sacrificed at 4, 24, 48, 72 and 168 h following 5 Gy ?-radiation exposure; control groups were excluded from exposure. Total leukocyte count and absolute lymphocyte count (ALC) and melatonin only of peripheral blood, stimulation index, thiobarbituric-acid-reactive substances (TBARS) level, superoxide dismutase (SOD) activity, and the apoptotic index of spleen as analysed by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labelling (TUNEL) noted at observed time-points were significantly reduced in melatonin pre-treated groups during RAP and RIP. Long-term melatonin pre-treatment mitigated radiation-induced alterations more prominently during RIP, as assessed by ALC, TBARS, SOD, TUNEL and caspase-3 activity, at some time-points. Our results demonstrate an inhibitory role of melatonin on caspase-3 activity in splenocytes during RAP and RIP following ?-radiation-induced caspase-mediated apoptosis. Hence, we propose that melatonin might preserve the viability of immune cells of a seasonal breeder against background radiation, which is constantly present in the environment. PMID:20139262

Sharma, S; Haldar, C; Chaube, S K; Laxmi, T; Singh, S S

2010-01-01

9

Seed traits and taxonomic relationships determine the occurrence of mutualisms versus seed predation in a tropical forest rodent and seed dispersal system.  

PubMed

Although many studies have been carried out on plant-animal mutualistic assemblages, the roles of functional traits and taxonomy in determining both whether interactions involve mutualisms or predation and the structure of such assemblages are unclear. We used semi-natural enclosures to quantitatively assess the interaction strengths between seeds of 8 sympatric tree species and 4 rodent species in a tropical forest in Xishuangbanna, Yunnan, Southwest China. We found 2 clusters of species in the seed-rodent network represented by 2 genera in the Fagaceae (Castanopsis, Lithocarpus). Compared to seeds of 3 Castanopsis species, seeds with heavy weight, hard coat or caloric content (including 3 Lithocarpus species) were eaten less and more frequently hoarded by rodents. In turn, hoarded seeds showed less predation and more mutualism with rodents. Our results suggest that seed traits significantly affected the hoarding behavior of rodents, and, consequently, the occurrence of mutualisms and predation as well as assemblage structure in the plant-animal seed dispersal system. Taxonomically-related species with similar seed traits as functional groups belong to the same substructures in the assemblage. Our results indicate that both seed traits and taxonomic relationships may simplify thinking about seed dispersal systems by helping to elucidate whether interactions are likely to be dominated by predation or mutualism. PMID:24382317

Wang, Zhenyu; Cao, Lin; Zhang, Zhibin

2014-06-01

10

The largest fossil rodent  

PubMed Central

The discovery of an exceptionally well-preserved skull permits the description of the new South American fossil species of the rodent, Josephoartigasia monesi sp. nov. (family: Dinomyidae; Rodentia: Hystricognathi: Caviomorpha). This species with estimated body mass of nearly 1000?kg is the largest yet recorded. The skull sheds new light on the anatomy of the extinct giant rodents of the Dinomyidae, which are known mostly from isolated teeth and incomplete mandible remains. The fossil derives from San José Formation, Uruguay, usually assigned to the Pliocene–Pleistocene (4–2?Myr ago), and the proposed palaeoenvironment where this rodent lived was characterized as an estuarine or deltaic system with forest communities. PMID:18198140

Rinderknecht, Andrés; Blanco, R. Ernesto

2008-01-01

11

Rodent models of glaucoma  

PubMed Central

Glaucoma is a progressive, age-related optic neuropathy and a leading cause of irreversible blindness in the world. Animal models of glaucoma are essential to our continued efforts of elucidating the natural course of the disease and to developing therapeutic interventions to halt or reverse the progression of the condition. Over the past 10–15 years, rodents have become a popular model organism in which to study glaucoma, because of their high degree of availability, relatively low cost, short life-span, and amenability to experimental and genetic manipulation. In this review, we examine the numerous in vivo and in vitro rodent models of glaucoma, discuss the methods used to generate them, summarize some of the major findings obtained in these models, and identify individual strengths and weaknesses for the various systems. PMID:19379796

Johnson, Thomas V.; Tomarev, Stanislav I.

2010-01-01

12

Microdialysis in Rodents  

PubMed Central

Microdialysis is an in vivo sampling technique that permits the quantification of various substances (e.g., neurotransmitters, peptides, electrolytes) in blood and tissue. It is also used to infuse substances into the brain and spinal cord. This unit describes methods for the construction and stereotaxic implantation of microdialysis probes into discrete brain regions of the rat and mouse. Procedures for the conduct of conventional and quantitative microdialysis experiments in the awake and anesthetized rodent are also provided. PMID:19340813

Zapata, Agustin; Chefer, Vladimir I.; Shippenberg, Toni S.

2010-01-01

13

Toxoplasmosis seroprevalence in urban rodents: a survey in Niamey, Niger  

PubMed Central

A serological survey of Toxoplasma gondii was conducted on 766 domestic and peridomestic rodents from 46 trapping sites throughout the city of Niamey, Niger. A low seroprevalence was found over the whole town with only 1.96% of the rodents found seropositive. However, differences between species were important, ranging from less than 2% in truly commensal Mastomys natalensis, Rattus rattus and Mus musculus, while garden-associated Arvicanthis niloticus displayed 9.1% of seropositive individuals. This is in line with previous studies on tropical rodents - that we reviewed here - which altogether show that Toxoplasma seroprevalence in rodent is highly variable, depending on many factors such as locality and/or species. Moreover, although we were not able to decipher statistically between habitat or species effect, such a contrast between Nile grass rats and the other rodent species points towards a potentially important role of environmental toxoplasmic infection. This would deserve to be further scrutinised since intra-city irrigated cultures are extending in Niamey, thus potentially increasing Toxoplasma circulation in this yet semi-arid region. As far as we are aware of, our study is one of the rare surveys of its kind performed in Sub-Saharan Africa and the first one ever conducted in the Sahel. PMID:23828008

Mercier, Aurélien; Garba, Madougou; Bonnabau, Henri; Kane, Mamadou; Rossi, Jean-Pierre; Dardé, Marie-Laure; Dobigny, Gauthier

2013-01-01

14

Thieving rodents as substitute dispersers of megafaunal seeds  

PubMed Central

The Neotropics have many plant species that seem to be adapted for seed dispersal by megafauna that went extinct in the late Pleistocene. Given the crucial importance of seed dispersal for plant persistence, it remains a mystery how these plants have survived more than 10,000 y without their mutualist dispersers. Here we present support for the hypothesis that secondary seed dispersal by scatter-hoarding rodents has facilitated the persistence of these large-seeded species. We used miniature radio transmitters to track the dispersal of reputedly megafaunal seeds by Central American agoutis, which scatter-hoard seeds in shallow caches in the soil throughout the forest. We found that seeds were initially cached at mostly short distances and then quickly dug up again. However, rather than eating the recovered seeds, agoutis continued to move and recache the seeds, up to 36 times. Agoutis dispersed an estimated 35% of seeds for >100 m. An estimated 14% of the cached seeds survived to the next year, when a new fruit crop became available to the rodents. Serial video-monitoring of cached seeds revealed that the stepwise dispersal was caused by agoutis repeatedly stealing and recaching each other’s buried seeds. Although previous studies suggest that rodents are poor dispersers, we demonstrate that communities of rodents can in fact provide highly effective long-distance seed dispersal. Our findings suggest that thieving scatter-hoarding rodents could substitute for extinct megafaunal seed dispersers of tropical large-seeded trees. PMID:22802644

Jansen, Patrick A.; Hirsch, Ben T.; Emsens, Willem-Jan; Zamora-Gutierrez, Veronica; Wikelski, Martin; Kays, Roland

2012-01-01

15

Toxoplasmosis seroprevalence in urban rodents: a survey in Niamey, Niger.  

PubMed

A serological survey of Toxoplasma gondii was conducted on 766 domestic and peridomestic rodents from 46 trapping sites throughout the city of Niamey, Niger. A low seroprevalence was found over the whole town with only 1.96% of the rodents found seropositive. However, differences between species were important, ranging from less than 2% in truly commensal Mastomys natalensis, Rattus rattus and Mus musculus, while garden-associated Arvicanthis niloticus displayed 9.1% of seropositive individuals. This is in line with previous studies on tropical rodents--that we reviewed here--which altogether show that Toxoplasma seroprevalence in rodent is highly variable, depending on many factors such as locality and/or species. Moreover, although we were not able to decipher statistically between habitat or species effect, such a contrast between Nile grass rats and the other rodent species points towards a potentially important role of environmental toxoplasmic infection. This would deserve to be further scrutinised since intra-city irrigated cultures are extending in Niamey, thus potentially increasing Toxoplasma circulation in this yet semi-arid region. As far as we are aware of, our study is one of the rare surveys of its kind performed in Sub-Saharan Africa and the first one ever conducted in the Sahel. PMID:23828008

Mercier, Aurélien; Garba, Madougou; Bonnabau, Henri; Kane, Mamadou; Rossi, Jean-Pierre; Dardé, Marie-Laure; Dobigny, Gauthier

2013-06-01

16

Geomagnetic field detection in rodents  

SciTech Connect

In addition to behavioral evidence for the detection of earth-strength magnetic fields (MF) by rodents, recent investigations have revealed that electrophysiological and biochemical responses to MF occur in the pineal organ and retina of rodents. In addition, ferrimagnetic deposits have been identified in the ethmoidal regions of the rodent skull. These findings point to a new sensory phenomenon, which interfaces with many fields of biology, including neuroscience, psychophysics, behavioral ecology, chronobiology and sensory physiology.

Olcese, J.; Reuss, S.; Semm, P.

1988-01-01

17

Tropical Belt  

NSDL National Science Digital Library

This lesson familiarizes learners with the term "tropical belt." First, learners locate the equator, Tropic of Cancer and Tropic of Capricorn on a map and trace these lines with a crayon. Learners also color in the locations of tropical rainforests. Next, learners cut along the colored lines of the Tropic of Cancer and Tropic of Capricorn. Educators can punch a hole at each end of this map and tie the ends together with yarn. Learners can wear the belt in class to remind themselves that rainforests are found near the equator or midsection of the Earth. This lesson includes extension ideas and is standards-based.

Sciences, California A.

2008-01-01

18

Lymphocytic Choriomeningitis Virus from Pet Rodents  

MedlinePLUS

... rodent? Rodents, such as mice, hamsters and guinea pigs, are popular as pets in many households. However, ... and pet mice, hamsters, and, on occasion, guinea pigs. What is LCMV? LCMV is carried by rodents ...

19

Tropical malabsorption  

PubMed Central

Malabsorption is an important clinical problem both in visitors to the tropics and in native residents of tropical countries. Infections of the small intestine are the most important cause of tropical malabsorption. Protozoal infections cause malabsorption in immunocompetent hosts, but do so more commonly in the setting of immune deficiency. Helminth infections occasionally cause malabsorption or protein?losing enteropathy. Intestinal tuberculosis, chronic pancreatitis and small?bowel bacterial overgrowth are important causes of tropical malabsorption. In recent years, inflammatory bowel disease and coeliac disease have become major causes of malabsorption in the tropics. Sporadic tropical sprue is still an important cause of malabsorption in adults and in children in South Asia. Investigations to exclude specific infective, immunological or inflammatory causes are important before considering tropical sprue as a diagnosis. This article briefly reviews the management of tropical sprue and presents an algorithm for its investigation and management. PMID:17148698

Ramakrishna, B S; Venkataraman, S; Mukhopadhya, A

2006-01-01

20

Tropical Glaciers  

NASA Astrophysics Data System (ADS)

The term "tropical glacier" calls to mind balmy nights and palm trees on one hand and cold, blue ice on the other. Certainly author Gabriel Garcia Marqez exploited this contrast in One Hundred Years of Solitude. We know that tropical fish live in warm, Sun-kissed waters and tropical plants provide lush, dense foliage populated by colorful tropical birds. So how do tropical glaciers fit into this scene? Like glaciers everywhere, tropical glaciers form where mass accumulation—usually winter snow—exceeds mass loss, which is generally summer melt. Thus, tropical glaciers exist at high elevations where precipitation can occur as snowfall exceeds melt and sublimation losses, such as the Rwenzori Mountains in east Africa and the Maoke Range of Irian Jaya.

Fountain, Andrew

21

Review: Population Fluctuations in Rodents  

E-print Network

interested in bats. Brock Fenton, Biology, University of Western On- tario, London, Ontario, Canada Population Fluctuations in Rodents. By Charles J. Krebs. Chicago (Illinois): University of Chicago Press. $55.00. x #2; 306 p.; ill.; index. ISBN: 978...

Armitage, Kenneth

2014-03-01

22

The allometry of rodent intestines  

Microsoft Academic Search

This study examined the allometry of the small intestine, caecum, colon and large intestine of rodents (n = 51) using a phylogenetically informed approach. Strong phylogenetic signal was detected in the data for the caecum, colon\\u000a and large intestine, but not for the small intestine. Most of the phylogenetic signal could be attributed to clade effects\\u000a associated with herbivorous versus omnivorous rodents.

Barry G. Lovegrove

2010-01-01

23

Tropical myelopathies.  

PubMed

A large number of causal agents produce spinal cord lesions in the tropics. Most etiologies found in temperate regions also occur in the tropics including trauma, herniated discs, tumors, epidural abscess, and congenital malformations. However, infectious and nutritional disorders occur with higher prevalence in tropical regions. Among the most common infectious etiologies are tuberculous Pott's disease, brucellosis, and neuroborreliosis. Parasitic diseases such as schistosomiasis, neurocysticercosis, and eosinophilic meningitis are frequent causes of nontraumatic paraplegia. The retrovirus HTLV-1 is a cause of tropical spastic paraparesis. Nutritional causes of paraparesis include deficiencies of vitamin B12 and folate; endemic clusters of konzo and tropical ataxic myeloneuropathy are associated in Africa with malnutrition and excessive consumption of cyanide-containing bitter cassava. Other toxic etiologies of tropical paraplegia include lathyrism and fluorosis. Nutritional forms of myelopathy are associated often with optic and sensory neuropathy, hence the name tropical myeloneuropathies. Acute transverse myelopathy is seen in association with vaccination, infections, and fibrocartilaginous embolism of the nucleus pulposus. Multiple sclerosis and optic myelopathy occur in the tropics but with lesser prevalence than in temperate regions. The advent of modern imaging in the tropics, including computed tomography and magnetic resonance imaging, has allowed better diagnosis and treatment of these conditions that are a frequent cause of death and disability. PMID:24365434

Román, Gustavo C

2014-01-01

24

Rodent phylogeny revised: analysis of six nuclear genes from all major rodent clades  

Microsoft Academic Search

BACKGROUND: Rodentia is the most diverse order of placental mammals, with extant rodent species representing about half of all placental diversity. In spite of many morphological and molecular studies, the family-level relationships among rodents and the location of the rodent root are still debated. Although various datasets have already been analyzed to solve rodent phylogeny at the family level, these

Shani Blanga-Kanfi; Hector Miranda; Osnat Penn; Tal Pupko; Ronald W DeBry; Dorothée Huchon

2009-01-01

25

Allometric disparity in rodent evolution  

PubMed Central

In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results indicate that the evolution of allometric trajectories in rodents is characterized by different features in sciurids compared with muroids and Ctenohystrica. Sciuridae was found to have a reduced magnitude of inter-trajectory change and growth patterns with less variation in allometric coefficient values among members. In contrast, a greater magnitude of difference between trajectories and an increased variation in allometric coefficient values was evident for both Ctenohystrica and muroids. Ctenohystrica and muroids achieved considerably higher adult disparities than sciurids, suggesting that conservatism in allometric trajectory modification may constrain morphological diversity in rodents. The results provide support for a role of ecology (dietary habit) in the evolution of allometric trajectories in rodents. PMID:23610638

Wilson, Laura A B

2013-01-01

26

Tropical Pyomyositis  

PubMed Central

Background: Tropical pyomyositis is characterized by suppuration within skeletal muscles, manifesting as single or multiple abscesses. Though primarily a disease of tropics, it is increasingly being reported from temperate regions in immunosuppressed patients. However, India has only few sporadic case reports. Aims: The aim of this study is to evaluate the causative organisms, clinical presentations, diagnostic modalities, treatment protocols and outcome data in tropical pyomyositis patients. Subjects and Methods: The study was carried out in Nilratan Sircar Medical College and Hospital, Kolkata over 3 years (July 2010 to June 2013). A total of 12 patients were diagnosed with tropical pyomyositis (confirmed with aspiration and culture of pus from muscle). All the investigation and treatment data were recorded systematically. Results: The presenting feature was high fever and myalgia in all 12 patients. Quadriceps femoris was the most commonly involved muscle (50%); followed by iliopsoas (25%). Culture of the aspirate showed Staphylococcus aureus in nine patients (75%), Klebsiella pneumonia in one patient (8.33%) and no growth in two patients (16.67%) even after tubercular and fungal culture. Conclusions: Tropical pyomyositis can affect immune-competent individuals. S. aureus is the most commonly cultured organism. Immediate initiation of appropriate antibiotics and surgical debridement are required to avoid complications. The prognosis remains excellent if promptly treated. PMID:24350072

Chattopadhyay, Bitoti; Mukhopadhyay, Mainak; Chatterjee, Atri; Biswas, Pijush Kanti; Chatterjee, Nandini; Debnath, Nirod Baran

2013-01-01

27

Tropical Cyclones John, Steve  

E-print Network

Tropical Cyclones John, Steve and Rosita Tropical Cyclone Season 1999--2000 #12;Tropical Cyclones John, Steve and Rosita Tropical Cyclone Season 1999­2000 © Commonwealth of Australia, August 2000 Hotel: Courtesy of WA Newspapers. #12;Tropical Cyclones John, Steve and Rosita 1 Tropical Cyclones John

Greenslade, Diana

28

Tropical Deforestation.  

ERIC Educational Resources Information Center

Outlines the deforestation problem and some efforts for solving the problem. Considers the impact of population growth, poverty, and ignorance. Includes a discussion of the current rapid decline in tropical forests, the consequences of destruction, and an outlook for the future. (YP)

Raven, Peter H.

1988-01-01

29

Urban resident attitudes toward rodents, rodent control products, and environmental effects  

EPA Science Inventory

Rodent control in urban areas can result in the inadvertent mortality of non-target species (e.g., bobcats). However, there is little detailed information about rodent control practices of urban residents. Our objective was to evaluate urban rodent control behaviors in two area...

30

Auditing laboratory rodent biosecurity programs.  

PubMed

A rodent biosecurity program that includes periodic evaluation of procedures used in an institution's vivarium can be used to ensure that best practices are in place to prevent a microbial pathogen outbreak. As a result of an ongoing comprehensive biosecurity review within their North American and European production facilities, the authors developed a novel biosecurity auditing process and worksheet that could be useful in other animal care and use operations. The authors encourage other institutions to consider initiating similar audits of their biosecurity programs to protect the health of their laboratory animals. PMID:24150170

Porter, William P; Horn, Mandy J; Cooper, Dale M; Klein, Hilton J

2013-10-22

31

B chromosomes in Brazilian rodents.  

PubMed

B chromosomes are now known in eight Brazilian rodent species: Akodon montensis, Holochilus brasiliensis, Nectomys rattus, N. squamipes, Oligoryzomys flavescens, Oryzomys angouya, Proechimys sp. 2 and Trinomys iheringi. Typically these chromosomes are heterogeneous relative to size, morphology, banding patterns, presence/absence of NORs, and presence/absence of interstitial telomeric signals after FISH. In most cases, Bs are heterochromatic and late replicating. Active NORs were detected in two species: Akodon montensis and Oryzomys angouya. As a rule, Bs behave as uni or bivalents in meiosis, there is no pairing between Bs and autosomes or sex chromosomes and also their synaptonemal complexes are isopycnotic with those in A chromosomes. PMID:15292600

Silva, M J J; Yonenaga-Yassuda, Y

2004-01-01

32

20 CFR 654.415 - Insect and rodent control.  

...2014-04-01 2014-04-01 false Insect and rodent control. 654.415 Section...Workers Housing Standards § 654.415 Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other...

2014-04-01

33

20 CFR 654.415 - Insect and rodent control.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Insect and rodent control. 654.415 Section...Workers Housing Standards § 654.415 Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other...

2012-04-01

34

20 CFR 654.415 - Insect and rodent control.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Insect and rodent control. 654.415 Section...Workers Housing Standards § 654.415 Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other...

2013-04-01

35

20 CFR 654.415 - Insect and rodent control.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Insect and rodent control. 654.415 Section...Workers Housing Standards § 654.415 Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other...

2011-04-01

36

20 CFR 654.415 - Insect and rodent control.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Insect and rodent control. 654.415 Section...Workers Housing Standards § 654.415 Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other...

2010-04-01

37

Rodent-Vegetation Relationships in Southeastern Montana  

Microsoft Academic Search

Plant communities of southeastern Montana were surveyed for rodents over a two year period. Deer mice (Peromyscus maniculatus) were the most abundant rodent species found on the study area. Prairie voles (Microtus ochrogaster), meadow voles (M. pennsylvanicus), sagebrush voles (Lagurus curtatus), Wyoming pocket mice (Perognathus fasciatus), thirteen-lined ground squirrels (Spermophilus tridecemlineatus), least chipmunks (Eutamias minimus), and eastern fox squirrels (Sciurus

Daniel W. Uresk; Richard M. Hansen

38

Analysis of Behavior in Laboratory Rodents  

Microsoft Academic Search

The nervous system is designed to produce behavior, and so behavioral analysis is the ultimate assay of neural function. In this chapter we provide an overview of the behavior of rodents. We also provide references for testing details. Most of the behavioral meth- odology comes from research on rats, but the ethograms of rodents are similar enough to allow for

Ian Q. Whishaw; Forrest Haun; Bryan Kolb

39

Rodent Models for Metabolic Syndrome Research  

PubMed Central

Rodents are widely used to mimic human diseases to improve understanding of the causes and progression of disease symptoms and to test potential therapeutic interventions. Chronic diseases such as obesity, diabetes and hypertension, together known as the metabolic syndrome, are causing increasing morbidity and mortality. To control these diseases, research in rodent models that closely mimic the changes in humans is essential. This review will examine the adequacy of the many rodent models of metabolic syndrome to mimic the causes and progression of the disease in humans. The primary criterion will be whether a rodent model initiates all of the signs, especially obesity, diabetes, hypertension and dysfunction of the heart, blood vessels, liver and kidney, primarily by diet since these are the diet-induced signs in humans with metabolic syndrome. We conclude that the model that comes closest to fulfilling this criterion is the high carbohydrate, high fat-fed male rodent. PMID:21253582

Panchal, Sunil K.; Brown, Lindsay

2011-01-01

40

Rodent phylogeny revised: analysis of six nuclear genes from all major rodent clades  

PubMed Central

Background Rodentia is the most diverse order of placental mammals, with extant rodent species representing about half of all placental diversity. In spite of many morphological and molecular studies, the family-level relationships among rodents and the location of the rodent root are still debated. Although various datasets have already been analyzed to solve rodent phylogeny at the family level, these are difficult to combine because they involve different taxa and genes. Results We present here the largest protein-coding dataset used to study rodent relationships. It comprises six nuclear genes, 41 rodent species, and eight outgroups. Our phylogenetic reconstructions strongly support the division of Rodentia into three clades: (1) a "squirrel-related clade", (2) a "mouse-related clade", and (3) Ctenohystrica. Almost all evolutionary relationships within these clades are also highly supported. The primary remaining uncertainty is the position of the root. The application of various models and techniques aimed to remove non-phylogenetic signal was unable to solve the basal rodent trifurcation. Conclusion Sequencing and analyzing a large sequence dataset enabled us to resolve most of the evolutionary relationships among Rodentia. Our findings suggest that the uncertainty regarding the position of the rodent root reflects the rapid rodent radiation that occurred in the Paleocene rather than the presence of conflicting phylogenetic and non-phylogenetic signals in the dataset. PMID:19341461

Blanga-Kanfi, Shani; Miranda, Hector; Penn, Osnat; Pupko, Tal; DeBry, Ronald W; Huchon, Dorothée

2009-01-01

41

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2012 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2012-04-01

42

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2013 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2013-04-01

43

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2010 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2010-04-01

44

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2011 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2011-04-01

45

21 CFR 1250.96 - Rodent control.  

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2014-04-01

46

Rodents as potential couriers for bioterrorism agents.  

PubMed

Many pathogens that can cause major public health, economic, and social damage are relatively easily accessible and could be used as biological weapons. Wildlife is a natural reservoir for many potential bioterrorism agents, and, as history has shown, eliminating a pathogen that has dispersed among wild fauna can be extremely challenging. Since a number of wild rodent species live close to humans, rodents constitute a vector for pathogens to circulate among wildlife, domestic animals, and humans. This article reviews the possible consequences of a deliberate spread of rodentborne pathogens. It is relatively easy to infect wild rodents with certain pathogens or to release infected rodents, and the action would be difficult to trace. Rodents can also function as reservoirs for diseases that have been spread during a bioterrorism attack and cause recurring disease outbreaks. As rats and mice are common in both urban and rural settlements, deliberately released rodentborne infections have the capacity to spread very rapidly. The majority of pathogens that are listed as potential agents of bioterrorism by the Centers for Disease Control and Prevention and the National Institute of Allergy and Infectious Diseases exploit rodents as vectors or reservoirs. In addition to zoonotic diseases, deliberately released rodentborne epizootics can have serious economic consequences for society, for example, in the area of international trade restrictions. The ability to rapidly detect introduced diseases and effectively communicate with the public in crisis situations enables a quick response and is essential for successful and cost-effective disease control. PMID:23971813

Lõhmus, Mare; Janse, Ingmar; van de Goot, Frank; van Rotterdam, Bart J

2013-09-01

47

The Fecal Viral Flora of Wild Rodents  

PubMed Central

The frequent interactions of rodents with humans make them a common source of zoonotic infections. To obtain an initial unbiased measure of the viral diversity in the enteric tract of wild rodents we sequenced partially purified, randomly amplified viral RNA and DNA in the feces of 105 wild rodents (mouse, vole, and rat) collected in California and Virginia. We identified in decreasing frequency sequences related to the mammalian viruses families Circoviridae, Picobirnaviridae, Picornaviridae, Astroviridae, Parvoviridae, Papillomaviridae, Adenoviridae, and Coronaviridae. Seventeen small circular DNA genomes containing one or two replicase genes distantly related to the Circoviridae representing several potentially new viral families were characterized. In the Picornaviridae family two new candidate genera as well as a close genetic relative of the human pathogen Aichi virus were characterized. Fragments of the first mouse sapelovirus and picobirnaviruses were identified and the first murine astrovirus genome was characterized. A mouse papillomavirus genome and fragments of a novel adenovirus and adenovirus-associated virus were also sequenced. The next largest fraction of the rodent fecal virome was related to insect viruses of the Densoviridae, Iridoviridae, Polydnaviridae, Dicistroviriade, Bromoviridae, and Virgaviridae families followed by plant virus-related sequences in the Nanoviridae, Geminiviridae, Phycodnaviridae, Secoviridae, Partitiviridae, Tymoviridae, Alphaflexiviridae, and Tombusviridae families reflecting the largely insect and plant rodent diet. Phylogenetic analyses of full and partial viral genomes therefore revealed many previously unreported viral species, genera, and families. The close genetic similarities noted between some rodent and human viruses might reflect past zoonoses. This study increases our understanding of the viral diversity in wild rodents and highlights the large number of still uncharacterized viruses in mammals. PMID:21909269

Phan, Tung G.; Kapusinszky, Beatrix; Wang, Chunlin; Rose, Robert K.; Lipton, Howard L.; Delwart, Eric L.

2011-01-01

48

The fecal viral flora of wild rodents.  

PubMed

The frequent interactions of rodents with humans make them a common source of zoonotic infections. To obtain an initial unbiased measure of the viral diversity in the enteric tract of wild rodents we sequenced partially purified, randomly amplified viral RNA and DNA in the feces of 105 wild rodents (mouse, vole, and rat) collected in California and Virginia. We identified in decreasing frequency sequences related to the mammalian viruses families Circoviridae, Picobirnaviridae, Picornaviridae, Astroviridae, Parvoviridae, Papillomaviridae, Adenoviridae, and Coronaviridae. Seventeen small circular DNA genomes containing one or two replicase genes distantly related to the Circoviridae representing several potentially new viral families were characterized. In the Picornaviridae family two new candidate genera as well as a close genetic relative of the human pathogen Aichi virus were characterized. Fragments of the first mouse sapelovirus and picobirnaviruses were identified and the first murine astrovirus genome was characterized. A mouse papillomavirus genome and fragments of a novel adenovirus and adenovirus-associated virus were also sequenced. The next largest fraction of the rodent fecal virome was related to insect viruses of the Densoviridae, Iridoviridae, Polydnaviridae, Dicistroviriade, Bromoviridae, and Virgaviridae families followed by plant virus-related sequences in the Nanoviridae, Geminiviridae, Phycodnaviridae, Secoviridae, Partitiviridae, Tymoviridae, Alphaflexiviridae, and Tombusviridae families reflecting the largely insect and plant rodent diet. Phylogenetic analyses of full and partial viral genomes therefore revealed many previously unreported viral species, genera, and families. The close genetic similarities noted between some rodent and human viruses might reflect past zoonoses. This study increases our understanding of the viral diversity in wild rodents and highlights the large number of still uncharacterized viruses in mammals. PMID:21909269

Phan, Tung G; Kapusinszky, Beatrix; Wang, Chunlin; Rose, Robert K; Lipton, Howard L; Delwart, Eric L

2011-09-01

49

Biodiversity Conservation in Tropical Agroecosystems  

E-print Network

Biodiversity Conservation in Tropical Agroecosystems A New Conservation Paradigm Ivette Perfectoa. This conclusion has major consequences for biodiversity con- servation in fragmented tropical forests the literature on biodiversity in tropical agricul- tural landscapes and present evidence that many tropical

50

Rodent-associated Bartonella in Saskatchewan, Canada.  

PubMed

Six species of wild rodents were sampled at 10 sites in 2002 and 2003 to determine the prevalence of Bartonella infections in rodent communities near Saskatoon, Saskatchewan, Canada. Isolates were characterized genotypically and compared with isolates found at other locations. Of 104 wild rodents examined, 57% were infected with Bartonella and prevalence within species varied from 49% for Richardson's ground squirrels (Spermophilus richardsonii) to 90% for Franklin's ground squirrels (S. franklinii). Infected rodents were found at all sites. Sequencing of a 379-bp portion of the citrate synthase gene was performed on 54 isolates and revealed 13 distinct genotypes, eight of which had not been described previously. The most common genotype detected in red-backed voles (Clethrionomys gapperi) was 99.1% similar to B. grahamii, a known human pathogen. Two of 10 Franklin's ground squirrels were concurrently infected with multiple Bartonella genotypes. All genotypes, with the exception of one detected in both Franklin's and thirteen-lined ground squirrels (S. tridecemlineatus), were found in only one host, and all genotypes from each species, with the exception of genotypes detected in red-backed voles, clustered together within the same relatedness group, suggesting that at least some Bartonella genotypes are specific to some rodent hosts. PMID:16417436

Jardine, Claire; Appleyard, Greg; Kosoy, Michael Y; McColl, Dorothy; Chirino-Trejo, Manuel; Wobeser, Gary; Leighton, Frederick A

2005-01-01

51

7 CFR 58.247 - Insect and rodent control program.  

Code of Federal Regulations, 2010 CFR

... false Insect and rodent control program. 58.247 Section 58.247 Agriculture Regulations of the Department of Agriculture...Service 1 Operations and Operating Procedures § 58.247 Insect and rodent control program. In...

2010-01-01

52

Persistence of brodifacoum in cockroach and woodlice: implications for secondary poisoning during rodent eradications.  

PubMed

When planning rodent eradications, that normally involve the use of the anticoagulant poison brodifacoum, it is imperative to minimise impacts on other "non-target" species that dwell alongside the targeted rodents and may indeed be the intended beneficiaries of the eradication. Such impacts can arise either from primary poisoning when the non-target species ingest bait pellets containing toxicant or by secondary poisoning when the non-target species eats prey that has itself eaten brodifacoum. Cockroaches and woodlice, likely to scavenge bait pellets, are widely distributed on tropical and sub-tropical islands where they are eaten by ground-dwelling birds. Combining work on Henderson Island, South Pacific, site of a recent rat eradication project, and UK laboratory experiments, our study first measured brodifacoum concentrations in cockroaches given temporary ad lib access to poison bait pellets, approximately mimicking the aftermath of bait distribution for a rodent eradication. In two separate experiments using different species/exposure times, the mean brodifacoum concentrations among cockroaches immediately after bait exposure was 262±s.e. 131 and 477±168µgkg(-1) wet weight. Values decreased quickly in the following 2 weeks, and then continued to decline at a slower rate over the following 4 weeks in the more prolonged laboratory experiment. A supplementary experiment with woodlice recorded a similar brodifacoum concentration in the animals at the end of the exposure period, 223±66µgkg(-1), and a similar time course for the post-exposure decline. In the context of rails (Rallidae), a group of birds known to be particularly susceptible to primary brodifacoum poisoning, these results suggested that, in terms of acute exposure, individual birds would need to eat a minimum of their own body weight (and more commonly 2-5 times that) of live cockroaches before facing a 50% risk of death. Therefore, we conclude that in eradication scenarios, acute secondary poisoning is of lower concern for these birds than primary poisoning. PMID:24008155

de L Brooke, M; Cuthbert, R J; Harrison, G; Gordon, C; Taggart, M A

2013-11-01

53

7 CFR 58.247 - Insect and rodent control program.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Insect and rodent control program. 58.247...and Operating Procedures § 58.247 Insect and rodent control program. In addition...the performance of a regularly scheduled insect and rodent control program as...

2011-01-01

54

7 CFR 58.247 - Insect and rodent control program.  

...2014-01-01 2014-01-01 false Insect and rodent control program. 58.247...and Operating Procedures § 58.247 Insect and rodent control program. In addition...the performance of a regularly scheduled insect and rodent control program as...

2014-01-01

55

7 CFR 58.147 - Insect and rodent control program.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Insect and rodent control program. 58.147...and Operating Procedures § 58.147 Insect and rodent control program. In addition...the performance of a regularly scheduled insect and rodent control program....

2012-01-01

56

7 CFR 58.147 - Insect and rodent control program.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Insect and rodent control program. 58.147...and Operating Procedures § 58.147 Insect and rodent control program. In addition...the performance of a regularly scheduled insect and rodent control program....

2010-01-01

57

7 CFR 58.147 - Insect and rodent control program.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Insect and rodent control program. 58.147...and Operating Procedures § 58.147 Insect and rodent control program. In addition...the performance of a regularly scheduled insect and rodent control program....

2011-01-01

58

7 CFR 58.247 - Insect and rodent control program.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Insect and rodent control program. 58.247...and Operating Procedures § 58.247 Insect and rodent control program. In addition...the performance of a regularly scheduled insect and rodent control program as...

2012-01-01

59

7 CFR 58.247 - Insect and rodent control program.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Insect and rodent control program. 58.247...and Operating Procedures § 58.247 Insect and rodent control program. In addition...the performance of a regularly scheduled insect and rodent control program as...

2013-01-01

60

7 CFR 58.147 - Insect and rodent control program.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Insect and rodent control program. 58.147...and Operating Procedures § 58.147 Insect and rodent control program. In addition...the performance of a regularly scheduled insect and rodent control program....

2013-01-01

61

7 CFR 58.147 - Insect and rodent control program.  

...2014-01-01 2014-01-01 false Insect and rodent control program. 58.147...and Operating Procedures § 58.147 Insect and rodent control program. In addition...the performance of a regularly scheduled insect and rodent control program....

2014-01-01

62

Seasonal selectivity of Magellanic horned owl ( Bubo magellanicus ) on rodents  

Microsoft Academic Search

This study examines prey selection by Magellanic horned owls (Bubo magellanicus) in an ecotonal steppe area of northwestern Argentine Patagonia, and analyzes morphological and behavioral traits of the owls’ main rodent prey. The owl’s diet was studied for two years, along with field estimates of rodent abundance. The frequency distribution of rodents was significantly different from that estimated from trapping,

Ana Trejo; Nadia Guthmann; Mariana Lozada

2005-01-01

63

Northwestern University New Researcher Checklist: Evanston Campus Rodent Users  

E-print Network

and Access to CCM Facilities Register for Facility Orientation and Hands-On Rodent Euthanasia o Contact the CCM Training Office to register for Facility Orientation and Hands-On Rodent Euthanasia training: 312-503-2758 o Facility Orientation and Hands-On Rodent Euthanasia are: Held on Tuesdays at 10:30am and Fridays

Contractor, Anis

64

NEOSPORA CANINUM DETECTED IN WILD RODENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The role of rodents in the epidemiology of neosporosis was investigated by assaying brain tissue of wild mice and rats for Neospora caninum. Both mouse and rat brain tissue were extracted for total DNA, and subjected to two different N. caninum-specific nested PCR assays. A portion of brain tissue...

65

Embargoed African Rodents and Monkeypox Virus  

MedlinePLUS

... distribution, transport, or release into the environment, of prairie dogs and six specific genera of African rodents. The joint order was enacted as part of the public health response to the first reported outbreak of monkeypox in the United States. On November 4, 2003, ...

66

Object Recognition Memory and the Rodent Hippocampus  

ERIC Educational Resources Information Center

In rodents, the novel object recognition task (NOR) has become a benchmark task for assessing recognition memory. Yet, despite its widespread use, a consensus has not developed about which brain structures are important for task performance. We assessed both the anterograde and retrograde effects of hippocampal lesions on performance in the NOR…

Broadbent, Nicola J.; Gaskin, Stephane; Squire, Larry R.; Clark, Robert E.

2010-01-01

67

Too many rodent carcinogens: Mitogenesis increases mutagenesis  

Microsoft Academic Search

A clarification of the mechanism of carcinogenesis is developing at a rapid rate. This new understanding undermines many assumptions of current regulatory policy toward rodent carcinogens and necessitates rethinking the utility and meaning of routine animal cancer tests. At a recent watershed meeting on carcinogenesis, much evidence was presented suggesting that mitogenesis plays a dominant role in carcinogenesis. Our own

B. N. Ames; L. S. Gold

1990-01-01

68

Climate, Deer, Rodents, and Acorns as Determinants  

E-print Network

Climate, Deer, Rodents, and Acorns as Determinants of Variation in Lyme-Disease Risk Richard S the determinants of Lyme-disease risk (density and Borrelia burgdorferi-infection prevalence of nymphal Ixodes Lyme disease (Dutchess County, New York). We used a model comparison approach to simultaneously test

69

Microbarom Sources from Tropical and Extra-tropical Cyclones  

E-print Network

Microbarom Sources from Tropical and Extra-tropical Cyclones Justin E. Stopa Co with similar frequencies most commonly generated in the lee of extra-tropical and tropical cyclones. The generation of microbaroms from within a tropical cyclone is demonstrated by the use of a parametric wind

Frandsen, Jannette B.

70

Novel Rodent Models for Macular Research  

PubMed Central

Background Many disabling human retinal disorders involve the central retina, particularly the macula. However, the commonly used rodent models in research, mouse and rat, do not possess a macula. The purpose of this study was to identify small laboratory rodents with a significant central region as potential new models for macular research. Methodology/Principal Findings Gerbillus perpallidus, Meriones unguiculatus and Phodopus campbelli, laboratory rodents less commonly used in retinal research, were subjected to confocal scanning laser ophthalmoscopy (cSLO), fluorescein and indocyanine green angiography, and spectral-domain optical coherence tomography (SD-OCT) using standard equipment (Heidelberg Engineering HRA1 and Spectralis™) adapted to small rodent eyes. The existence of a visual streak-like pattern was assessed on the basis of vascular topography, retinal thickness, and the topography of retinal ganglion cells and cone photoreceptors. All three species examined showed evidence of a significant horizontal streak-like specialization. cSLO angiography and retinal wholemounts revealed that superficial retinal blood vessels typically ramify and narrow into a sparse capillary net at the border of the respective area located dorsal to the optic nerve. Similar to the macular region, there was an absence of larger blood vessels in the streak region. Furthermore, the thickness of the photoreceptor layer and the population density of neurons in the ganglion cell layer were markedly increased in the visual streak region. Conclusions/Significance The retinal specializations of Gerbillus perpallidus, Meriones unguiculatus and Phodopus campbelli resemble features of the primate macula. Hence, the rodents reported here may serve to study aspects of macular development and diseases like age-related macular degeneration and diabetic macular edema, and the preclinical assessment of therapeutic strategies. PMID:20976212

Huber, Gesine; Heynen, Severin; Imsand, Coni; vom Hagen, Franziska; Muehlfriedel, Regine; Tanimoto, Naoyuki; Feng, Yuxi; Hammes, Hans-Peter; Grimm, Christian; Peichl, Leo; Seeliger, Mathias W.; Beck, Susanne C.

2010-01-01

71

Molecular epidemiology of paramyxoviruses in Zambian wild rodents and shrews.  

PubMed

Rodents and shrews are known to harbour various viruses. Paramyxoviruses have been isolated from Asian and Australian rodents, but little is known about them in African rodents. Recently, previously unknown paramyxovirus sequences were found in South African rodents. To date, there have been no reports related to the presence and prevalence of paramyxoviruses in shrews. We found a high prevalence of paramyxoviruses in wild rodents and shrews from Zambia. Semi-nested reverse transcription-PCR assays were used to detect paramyxovirus RNA in 21 % (96/462) of specimens analysed. Phylogenetic analysis revealed that these viruses were novel paramyxoviruses and could be classified as morbillivirus- and henipavirus-related viruses, and previously identified rodent paramyxovirus-related viruses. Our findings suggest the circulation of previously unknown paramyxoviruses in African rodents and shrews, and provide new information regarding the geographical distribution and genetic diversity of paramyxoviruses. PMID:24189618

Sasaki, Michihito; Muleya, Walter; Ishii, Akihiro; Orba, Yasuko; Hang'ombe, Bernard M; Mweene, Aaron S; Moonga, Ladslav; Thomas, Yuka; Kimura, Takashi; Sawa, Hirofumi

2014-02-01

72

Rodent models of TDP-43: Recent advances  

PubMed Central

Recently, missense mutations in the gene TARDBP encoding TDP-43 have been linked to familial ALS. The discovery of genes encoding these RNA binding proteins, such as TDP-43 and FUS/TLS, raised the notion that altered RNA metabolism is a major factor underlying the pathogenesis of ALS. To begin to unravel how mutations in TDP-43 cause dysfunction and death of motor neurons, investigators have employed both gain- and loss-of-function studies in rodent model systems. Here, we will summarize major findings from the initial sets of TDP-43 transgenic and knockout rodent models, identify their limitations, and point to future directions toward clarification of disease mechanism(s) and testing of therapeutic strategies that ultimately may lead to novel therapy for this devastating disease. PMID:22608070

Tsao, William; Jeong, Yun Ha; Lin, Sophie; Ling, Jonathan; Price, Donald L.; Chiang, Po-Min; Wong, Philip C.

2013-01-01

73

Neurogenetics of Aggressive Behavior – Studies in Rodents  

PubMed Central

Aggressive behavior is observed in many animal species, such as insects, fish, lizards, frogs, and most mammals including humans. This wide range of conservation underscores the importance of aggressive behavior in the animals’ survival and fitness, and the likely heritability of this behavior. Although typical patterns of aggressive behavior differ between species, there are several concordances in the neurobiology of aggression among rodents, primates, and humans. Studies with rodent models may eventually help us to understand the neurogenetic architecture of aggression in humans. However, it is important to recognize the difference between the ecological and ethological significance of aggressive behavior (species-typical aggression) and maladaptive violence (escalated aggression) when applying the findings of aggression research using animal models to human or veterinary medicine. Well-studied rodent models for aggressive behavior in the laboratory setting include the mouse (Mus musculus), rat (Rattus norvegicus), hamster (Mesocricetus auratus), and prairie vole (Microtus ochrogaster). The neural circuits of rodent aggression have been gradually elucidated by several techniques e.g. immunohistochemistry of immediate-early gene (c-Fos) expression, intracranial drug microinjection, in vivo microdialysis, and optogenetics techniques. Also, evidence accumulated from the analysis of gene-knockout mice shows the involvement of several genes in aggression. Here we review the brain circuits that have been implicated in aggression, such as the hypothalamus, prefrontal cortex (PFC), dorsal raphe nucleus (DRN), nucleus accumbens (NAc), and olfactory system. We then discuss the roles of glutamate and ?-aminobutyric acid (GABA), major inhibitory and excitatory amino acids in the brain, as well as their receptors, in controlling aggressive behavior, focusing mainly on recent findings. At the end of this chapter, we discuss how genes can be identified that underlie individual differences in aggression, using the so-called forward genetics approach. PMID:24318936

Takahashi, Aki; Miczek, Klaus A.

2014-01-01

74

Evidence for Novel Hepaciviruses in Rodents  

PubMed Central

Hepatitis C virus (HCV) is among the most relevant causes of liver cirrhosis and hepatocellular carcinoma. Research is complicated by a lack of accessible small animal models. The systematic investigation of viruses of small mammals could guide efforts to establish such models, while providing insight into viral evolutionary biology. We have assembled the so-far largest collection of small-mammal samples from around the world, qualified to be screened for bloodborne viruses, including sera and organs from 4,770 rodents (41 species); and sera from 2,939 bats (51 species). Three highly divergent rodent hepacivirus clades were detected in 27 (1.8%) of 1,465 European bank voles (Myodes glareolus) and 10 (1.9%) of 518 South African four-striped mice (Rhabdomys pumilio). Bats showed anti-HCV immunoblot reactivities but no virus detection, although the genetic relatedness suggested by the serologic results should have enabled RNA detection using the broadly reactive PCR assays developed for this study. 210 horses and 858 cats and dogs were tested, yielding further horse-associated hepaciviruses but none in dogs or cats. The rodent viruses were equidistant to HCV, exceeding by far the diversity of HCV and the canine/equine hepaciviruses taken together. Five full genomes were sequenced, representing all viral lineages. Salient genome features and distance criteria supported classification of all viruses as hepaciviruses. Quantitative RT-PCR, RNA in-situ hybridisation, and histopathology suggested hepatic tropism with liver inflammation resembling hepatitis C. Recombinant serology for two distinct hepacivirus lineages in 97 bank voles identified seroprevalence rates of 8.3 and 12.4%, respectively. Antibodies in bank vole sera neither cross-reacted with HCV, nor the heterologous bank vole hepacivirus. Co-occurrence of RNA and antibodies was found in 3 of 57 PCR-positive bank vole sera (5.3%). Our data enable new hypotheses regarding HCV evolution and encourage efforts to develop rodent surrogate models for HCV. PMID:23818848

Drexler, Jan Felix; Corman, Victor Max; Müller, Marcel Alexander; Lukashev, Alexander N.; Gmyl, Anatoly; Coutard, Bruno; Adam, Alexander; Ritz, Daniel; Leijten, Lonneke M.; van Riel, Debby; Kallies, Rene; Klose, Stefan M.; Gloza-Rausch, Florian; Binger, Tabea; Annan, Augustina; Adu-Sarkodie, Yaw; Oppong, Samuel; Bourgarel, Mathieu; Rupp, Daniel; Hoffmann, Bernd; Schlegel, Mathias; Kümmerer, Beate M.; Krüger, Detlev H.; Schmidt-Chanasit, Jonas; Setién, Alvaro Aguilar; Cottontail, Veronika M.; Hemachudha, Thiravat; Wacharapluesadee, Supaporn; Osterrieder, Klaus; Bartenschlager, Ralf; Matthee, Sonja; Beer, Martin; Kuiken, Thijs; Reusken, Chantal; Leroy, Eric M.; Ulrich, Rainer G.; Drosten, Christian

2013-01-01

75

Rodent evolution: back to the root.  

PubMed

Some 70 Ma, rodents arose along a branch of our own mammalian lineage. Today, about 40% of all mammalian species are rodents and are found in vast numbers on almost every continent. Not only is their proliferation extensive but also the rates of DNA evolution vary significantly among lineages, which has hindered attempts to reconstruct, especially the root of, their evolutionary history. The presence or absence of rare genomic changes, such as short interspersed elements (SINEs), are, however, independent of high molecular substitution rates and provide a powerful, virtually homoplasy-free source for solving such phylogenetic problems. We screened 12 Gb of rodent genomic information using whole-genome three-way alignments, multiple lineage-specific sequences, high-throughput polymerase chain reaction amplifications, and sequencing to reveal 65 phylogenetically informative SINE insertions dispersed over 23 rodent phylogenetic nodes. Eight SINEs and six indels provide significant support for an early association of the Mouse-related and Ctenohystrica (guinea pig and relatives) clades, the Squirrel-related clade being the sister group. This early speciation scenario was also evident in the genomewide distribution pattern of B1-related retroposons, as mouse and guinea pig genomes share six such retroposon subfamilies, containing hundreds of thousands of elements that are clearly absent in the ground squirrel genome. Interestingly, however, two SINE insertions and one diagnostic indel support an association of Ctenohystrica with the Squirrel-related clade. Lineage sorting or a more complex evolutionary scenario that includes an early divergence of the Squirrel-related ancestor and a subsequent hybridization of the latter and the Ctenohystrica lineage best explains such apparently contradictory insertions. PMID:20100942

Churakov, Gennady; Sadasivuni, Manoj K; Rosenbloom, Kate R; Huchon, Dorothée; Brosius, Jürgen; Schmitz, Jürgen

2010-06-01

76

Neurogenetics of aggressive behavior: studies in rodents.  

PubMed

Aggressive behavior is observed in many animal species, such as insects, fish, lizards, frogs, and most mammals including humans. This wide range of conservation underscores the importance of aggressive behavior in the animals' survival and fitness, and the likely heritability of this behavior. Although typical patterns of aggressive behavior differ between species, there are several concordances in the neurobiology of aggression among rodents, primates, and humans. Studies with rodent models may eventually help us to understand the neurogenetic architecture of aggression in humans. However, it is important to recognize the difference between the ecological and ethological significance of aggressive behavior (species-typical aggression) and maladaptive violence (escalated aggression) when applying the findings of aggression research using animal models to human or veterinary medicine. Well-studied rodent models for aggressive behavior in the laboratory setting include the mouse (Mus musculus), rat (Rattus norvegicus), hamster (Mesocricetus auratus), and prairie vole (Microtus ochrogaster). The neural circuits of rodent aggression have been gradually elucidated by several techniques, e.g., immunohistochemistry of immediate-early gene (c-Fos) expression, intracranial drug microinjection, in vivo microdialysis, and optogenetics techniques. Also, evidence accumulated from the analysis of gene-knockout mice shows the involvement of several genes in aggression. Here, we review the brain circuits that have been implicated in aggression, such as the hypothalamus, prefrontal cortex (PFC), dorsal raphe nucleus (DRN), nucleus accumbens (NAc), and olfactory system. We then discuss the roles of glutamate and ?-aminobutyric acid (GABA), excitatory and inhibitory amino acids in the brain, as well as their receptors, in controlling aggressive behavior, focusing mainly on recent findings. At the end of this chapter, we discuss how genes can be identified that underlie individual differences in aggression, using the so-called forward genetics approach. PMID:24318936

Takahashi, Aki; Miczek, Klaus A

2014-01-01

77

Tropical Prediction Center  

NSDL National Science Digital Library

The Tropical Prediction Center Web site is maintained by the National Weather Service of NOAA. Visitors will find current information on tropical storms and hurricanes, including public advisories. Also available are hurricane facts, historical data, tracking charts, satellite imagery, season summaries, and a wealth of other interesting and important information.

78

TROPICAL SPIDERWORT - AN INTRODUCTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tropical spiderwort (also known as Benghal dayflower) has gone from relative obscurity as a roadside curiosity to troublesome weed with widespread economic impact in Georgia in less than 10 years. South Georgia and Florida are currently plagued by tropical spiderwort, but isolated populations have ...

79

Tropical cyclone formation  

Microsoft Academic Search

The physics of tropical cyclone formation is not well understood, and more is known about the mature hurricane than the formative mechanisms that produce it. It is believed part of the reason for this can be traced to insufficient upper-level atmospheric data. Recent observations suggest that tropical cyclones are initiated by asymmetric interactions associated with migratory upper-level potential vorticity disturbances

Michael T. Montgomery; Brian F. Farrell

1993-01-01

80

Rodents and risk in the mekong delta of Vietnam: seroprevalence of selected zoonotic viruses in rodents and humans.  

PubMed

In the Mekong Delta in southern Vietnam, rats are commonly traded in wet markets and sold live for food consumption. We investigated seroprevalence to selected groups of rodent-borne viruses among human populations with high levels of animal exposure and among co-located rodent populations. The indirect fluorescence antibody test (IFAT) was used to determine seropositivity to representative reference strains of hantaviruses (Dobrava virus [DOBV], Seoul virus [SEOV]), cowpox virus, arenaviruses (lymphocytic choriomeningitis virus [LCMV]), flaviviruses (tick-borne encephalitis virus [TBEV]), and rodent parechoviruses (Ljungan virus), using sera from 245 humans living in Dong Thap Province and 275 rodents representing the five common rodent species sold in wet markets and present in peridomestic and farm settings. Combined seropositivity to DOBV and SEOV among the rodents and humans was 6.9% (19/275) and 3.7% (9/245), respectively; 1.1% (3/275) and 4.5% (11/245) to cowpox virus; 5.4% (15/275) and 47.3% (116/245) for TBEV; and exposure to Ljungan virus was 18.8% (46/245) in humans, but 0% in rodents. Very little seroreactivity was observed to LCMV in either rodents (1/275, 0.4%) or humans (2/245, 0.8%). Molecular screening of rodent liver tissues using consensus primers for flaviviruses did not yield any amplicons, whereas molecular screening of rodent lung tissues for hantavirus yielded one hantavirus sequence (SEOV). In summary, these results indicate low to moderate levels of endemic hantavirus circulation, possible circulation of a flavivirus in rodent reservoirs, and the first available data on human exposures to parechoviruses in Vietnam. Although the current evidence suggests only limited exposure of humans to known rodent-borne diseases, further research is warranted to assess public health implications of the rodent trade. PMID:25629782

Van Cuong, Nguyen; Carrique-Mas, Juan; Vo Be, Hien; An, Nguyen Ngoc; Tue, Ngo Tri; Anh, Nguyet Lam; Anh, Pham Hong; Phuc, Nguyen The; Baker, Stephen; Voutilainen, Liina; Jääskeläinen, Anne; Huhtamo, Eili; Utriainen, Mira; Sironen, Tarja; Vaheri, Antti; Henttonen, Heikki; Vapalahti, Olli; Chaval, Yannick; Morand, Serge; Bryant, Juliet E

2015-01-01

81

Leptospira and Rodents in Cambodia: Environmental Determinants of Infection  

PubMed Central

We investigated infection of rodents and shrews by Leptospira spp. in two localities of Cambodia (Veal Renh, Kaev Seima) and in four types of habitat (forests, non-flooded lands, lowland rain-fed paddy fields, houses) during the wet and the dry seasons. Habitat preference was common, and rodent and shrew species were found only in houses or in rain-fed paddy fields or in forests. Among 649 small mammals trapped belonging to 12 rodent species and 1 shrew species, 71 of 642 animals tested were carriers of Leptospira according to the 16S ribosomal RNA marker used. Rodent infection was higher in low-slope locations, corresponding to rain-fed paddy fields, especially in the rainy season and in Kaev Seima. Rodents (Rattus exulans) and shrews (Suncus murinus) inhabiting households showed significantly low levels of infections, whereas rodents living in and near to forests (shrubby wasteland, orchards) showed high levels of infection. PMID:22665613

Ivanova, Svilena; Herbreteau, Vincent; Blasdell, Kim; Chaval, Yannick; Buchy, Philippe; Guillard, Bertrand; Morand, Serge

2012-01-01

82

Diversity of the rodent communities in the Turan Desert region.  

PubMed

We assessed the diversity of rodent communities in the deserts of Russia, Kazakhstan, and Central Asia using geographic information system technology. There are 66 species of rodents, belonging to eight faunistic complexes, inhabiting this area. We discuss the geographical changes occurring in taxonomic and zoogeographic diversity at both species and community levels. Communities of gerbils and jerboas dominate in the Turan Desert region (66% of the area). Steppe communities of susliks penetrate the deserts from the north. Farming in deserts causes the replacement of native rodent communities with mouse communities or completely eradicates rodents in their main habitats. PMID:21396008

Neronov, Valery M; Khlyap, Ludmila A; Warshavsky, Andrey A

2006-12-01

83

Susceptibility of laboratory rodents to Trichinella papuae.  

PubMed

Members of the genus Trichinella are small nematodes that can infect a wide range of animal hosts. However, their infectivity varies depending on the parasite and host species combination. In this study, we examined the susceptibility of 4 species of laboratory rodents, i.e., mice, rats, hamsters, and gerbils to Trichinella papuae, an emerging non-encapsulated Trichinella species. Trichinella spiralis and Trichinella pseudospiralis were also included in this study for comparison. Fifteen animals of each rodent species were infected orally with 100 muscle larvae of each Trichinella species. Intestinal worm burden was determined at day 6 and 10 post-inoculation (PI). The numbers of muscle larvae were examined at day 45 PI. The reproductive capacity index (RCI) of the 3 Trichinella species in different rodent hosts was determined. By day 6 PI, 33.2-69.6% of the inoculated larvae of the 3 Trichinella species became adult worms in the small intestines of the host animals. However, in rats, more than 96% of adult worms of all 3 Trichinella species were expelled from the gut by day 10 PI. In gerbils, only 4.8-18.1% of adult worms were expelled by day 10 PI. In accordance with the intestinal worm burden and the persistence of adults, the RCI was the highest in gerbils with values of 241.5±41.0 for T. papuae, 432.6±48 for T. pseudospiralis, and 528.6±20.6 for T. spiralis. Hamsters ranked second and mice ranked third in susceptibility in terms of the RCI, Rats yielded the lowest parasite RCI for all 3 Trichinella species. Gerbils may be an alternative laboratory animal for isolation and maintenance of Trichinella spp. PMID:24516265

Sadaow, Lakkhana; Intapan, Pewpan M; Boonmars, Thidarut; Morakote, Nimit; Maleewong, Wanchai

2013-12-01

84

Tropical Spastic Paraparesis  

MedlinePLUS

... HTLV-1 associated myelopathy/ tropical spastic paraparesis or HAM/TSP. The HTLV-1 retrovirus is thought to ... at least 80 percent of the cases of HAM/TSP by impairing the immune system. In addition ...

85

Deforestation in the Tropics  

SciTech Connect

Government policies that encourage exploitation--in particular excessive logging and clearing for ranches and farms--are largely to blame for the accelerating destruction of tropical forests. This paper surveys the problem in detail and briefly recommends potential solutions.

Repetto, R. (World Resources Institute, Washington, DC (USA))

1990-04-01

86

Deforestation in the Tropics  

Microsoft Academic Search

Government policies that encourage exploitation--in particular excessive logging and clearing for ranches and farms--are largely to blame for the accelerating destruction of tropical forests. This paper surveys the problem in detail and briefly recommends potential solutions.

Robert Repetto

1990-01-01

87

Tolerance in the Tropics  

NSDL National Science Digital Library

Although temperatures are predicted to rise the most in northern latitudes due to global warming, tropical plants and animals might have the most difficult time adapting to climate change. This radio broadcast explains how temperature varies by only a couple of degrees annually in the tropics, and organisms there have a narrow range of temperature tolerance. The clip is 2 minutes in length and is available in MP3 format.

Katt-Reinders, Elizabeth

88

Tropical Severe Local Storms  

NSDL National Science Digital Library

The module provides a brief overview of severe local storms in the tropics. Basic ingredients for thunderstorms and assessment of thunderstorm potential from soundings are described. Then properties and hazards of ordinary thunderstorms, multicellular thunderstorms, supercells are reviewed. Conditions conducive to supercell formation in the tropics are examined along with methods of identifying them in radar and satellite images. Supercell and non-supercell tornado properties and formation are described. Finally, tornadoes, waterspouts, and dust devils properties are compared.

2014-09-14

89

Competition between harvester ants and rodents in the cold desert  

Microsoft Academic Search

Local distribution patterns of three rodent species (Perognathus parvus, Peromyscus maniculatus, Reithrodontomys megalotis) were studied in areas of high and low densities of harvester ants (Pogonomyrmex owyheei) in Raft River Valley, Idaho. Numbers of rodents were greatest in areas of high ant-density during May, but partially reduced in August; whereas, the trend was reversed in areas of low ant-density. Seed

D. S. Landeen; C. D. Jorgensen; H. D. Smith

1979-01-01

90

Visual Landmarks Facilitate Rodent Spatial Navigation in Virtual Reality Environments  

ERIC Educational Resources Information Center

Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain…

Youngstrom, Isaac A.; Strowbridge, Ben W.

2012-01-01

91

Lurking in the Shadows: Emerging Rodent Infectious Diseases  

PubMed Central

Rodent parvoviruses, Helicobacter spp., murine norovirus, and several other previously unknown infectious agents have “emerged” in laboratory rodents relatively recently. These agents have been discovered serendipitously or through active investigation of atypical serology results, cell culture contamination, unexpected histopathology, or previously unrecognized clinical disease syndromes. The potential research impact of these agents is not fully known. Infected rodents have demonstrated immunomodulation, tumor suppression, clinical disease (particularly in immunodeficient rodents), and histopathology. Perturbations of organismal and cellular physiology also likely occur. These agents posed unique challenges to laboratory animal resource programs once discovered; it was necessary to develop specific diagnostic assays and an understanding of their epidemiology and transmission routes before attempting eradication, and then evaluate eradication methods for efficacy. Even then management approaches varied significantly, from apathy to total exclusion, and such inconsistency has hindered the sharing and transfer of rodents among institutions, particularly for genetically modified rodent models that may not be readily available. As additional infectious agents are discovered in laboratory rodents in coming years, much of what researchers have learned from experiences with the recently identified pathogens will be applicable. This article provides an overview of the discovery, detection, and research impact of infectious agents recently identified in laboratory rodents. We also discuss emerging syndromes for which there is a suspected infectious etiology, and the unique challenges of managing newly emerging infectious agents. PMID:18506061

Besselsen, David G.; Franklin, Craig L.; Livingston, Robert S.; Riley, Lela K.

2013-01-01

92

Detection of Newly Recognized Rodent Parvoviruses by PCR  

Microsoft Academic Search

Several autonomous parvovirus isolates distinct from the prototypic rodent parvoviruses have recently been identified. These include variants of a mouse orphan parvovirus (MOPV) and a hamster isolate designated hamster orphan parvovirus (HOPV). In this study, a PCR primer set specific for these newly identified rodent parvoviruses was designed on the basis of DNA sequence comparisons of these isolates with other

DAVID G. BESSELSEN; CYNTHIA L. BESCH-WILLIFORD; DAVID J. PINTEL; CRAIG L. FRANKLIN; REUEL R. HOOK; ANDLELA K. RILEY

1995-01-01

93

Prospects of chemosterilant and genetic control of rodents  

PubMed Central

This paper discusses some requirements of an ideal rodent chemosterilant, analyses the advantages of chemosterilants over other control methods, and compares the potential values of chemosterilants that affect females, males, and both sexes. Examples are given of specific situations where chemosterilants will be valuable in rodent control, together with suggested methods of applying them. The theory and practicability of using genetics in rodent control are also discussed. Neither the chemosterilant nor the genetic method is expected to become a panacea, but their eventual application will be a significant advance in rodent-control technology. Since both approaches are based on sound biological principles and are relatively safe, they should be helpful in regulating rodent populations in the future. PMID:4583051

Marsh, Rex E.; Howard, Walter E.

1973-01-01

94

Epidemiology of Leptospira Transmitted by Rodents in Southeast Asia  

PubMed Central

Background Leptospirosis is the most common bacterial zoonoses and has been identified as an important emerging global public health problem in Southeast Asia. Rodents are important reservoirs for human leptospirosis, but epidemiological data is lacking. Methodology/Principal Findings We sampled rodents living in different habitats from seven localities distributed across Southeast Asia (Thailand, Lao PDR and Cambodia), between 2009 to 2010. Human isolates were also obtained from localities close to where rodents were sampled. The prevalence of Leptospira infection was assessed by real-time PCR using DNA extracted from rodent kidneys, targeting the lipL32 gene. Sequencing rrs and secY genes, and Multi Locus Variable-number Tandem Repeat (VNTR) analyses were performed on DNA extracted from rat kidneys for Leptospira isolates molecular typing. Four species were detected in rodents, L. borgpetersenii (56% of positive samples), L. interrogans (36%), L. kirschneri (3%) and L. weilli (2%), which were identical to human isolates. Mean prevalence in rodents was approximately 7%, and largely varied across localities and habitats, but not between rodent species. The two most abundant Leptospira species displayed different habitat requirements: L. interrogans was linked to humid habitats (rice fields and forests) while L. borgpetersenii was abundant in both humid and dry habitats (non-floodable lands). Conclusion/Significance L. interrogans and L. borgpetersenii species are widely distributed amongst rodent populations, and strain typing confirmed rodents as reservoirs for human leptospirosis. Differences in habitat requirements for L. interrogans and L. borgpetersenii supported differential transmission modes. In Southeast Asia, human infection risk is not only restricted to activities taking place in wetlands and rice fields as is commonly accepted, but should also include tasks such as forestry work, as well as the hunting and preparation of rodents for consumption, which deserve more attention in future epidemiological studies. PMID:24901706

Mielcarek, Mathilde; Tatard, Caroline; Chaval, Yannick; Suputtamongkol, Yupin; Buchy, Philippe; Jittapalapong, Sathaporn; Herbreteau, Vincent; Morand, Serge

2014-01-01

95

Domestic Rodent Control Training Manual: A Training Aid for the Rodent Control Category for Certification of Pesticide Applicators.  

ERIC Educational Resources Information Center

This training manual, designed for training applicants who wish to obtain certification in pesticide application relative to rodent control, covers the following topics: economic factors, public health factors, biological characteristics of domestic rodents, rat and mouse signs, trapping, repellents, poisons, baits, poisoned water, dumps, sewers,…

Childress, William R., Jr.; And Others

96

Guidelines for Euthanasia of Rodents Using Carbon Dioxide Rodents must be euthanized by trained personnel using appropriate technique, equipment and  

E-print Network

1 Guidelines for Euthanasia of Rodents Using Carbon Dioxide Rodents must be euthanized by trained, euthanasia should not be performed in the animal room. The euthanasia method must be appropriate to the most recent AVMA Guidelines on Euthanasia.1 CO2 inhalation is the most common method of euthanasia used

Bandettini, Peter A.

97

Latitudinal patterns in rodent metabolic flexibility.  

PubMed

Macrophysiology is defined as the study of variation in physiological traits-including physiological trait flexibility-over large geographical and temporal scales, and the ecological implications of this variation. A classic example of a macrophysiological trend is the one emerging from the climatic variability hypothesis, which states that as the range of climatic fluctuation experienced by terrestrial animals increases with latitude, individuals at higher latitudes should be more plastic than individuals inhabiting lower latitudes. In this context, we evaluate the correlation between absolute metabolic scope during cold exposure (an instantaneous measure of metabolic flexibility) and different geographic and climatic variables for 48 rodent species. Conventional and phylogenetic informed analyses indicated a positive correlation between metabolic scope and geographic latitude. These findings, together with previous reports on latitudinal pattern in phenotypic flexibility, suggest that an increase in physiological flexibility with latitude may hold for many phenotypic traits. PMID:22617269

Naya, Daniel E; Spangenberg, Lucia; Naya, Hugo; Bozinovic, Francisco

2012-06-01

98

Intraoperative cerebral blood flow imaging of rodents  

NASA Astrophysics Data System (ADS)

Intraoperative monitoring of cerebral blood flow (CBF) is of interest to neuroscience researchers, which offers the assessment of hemodynamic responses throughout the process of neurosurgery and provides an early biomarker for surgical guidance. However, intraoperative CBF imaging has been challenging due to animal's motion and position change during the surgery. In this paper, we presented a design of an operation bench integrated with laser speckle contrast imager which enables monitoring of the CBF intraoperatively. With a specially designed stereotaxic frame and imager, we were able to monitor the CBF changes in both hemispheres during the rodent surgery. The rotatable design of the operation plate and implementation of online image registration allow the technician to move the animal without disturbing the CBF imaging during surgery. The performance of the system was tested by middle cerebral artery occlusion model of rats.

Li, Hangdao; Li, Yao; Yuan, Lu; Wu, Caihong; Lu, Hongyang; Tong, Shanbao

2014-09-01

99

Tropical rainforest biodiversity: field and  

E-print Network

Tropical rainforest biodiversity: field and GIS tools for assessing, monitoring and mapping II. Francesco Rovero, Curator, (tropical biodiversity and forest mammal expert) and Dr. Clara Tattoni, Research international biodiversity experts will teach specific modules. In collaboration with: Further information

100

Tropical cyclone formation  

SciTech Connect

The physics of tropical cyclone formation is not well understood, and more is known about the mature hurricane than the formative mechanisms that produce it. It is believed part of the reason for this can be traced to insufficient upper-level atmospheric data. Recent observations suggest that tropical cyclones are initiated by asymmetric interactions associated with migratory upper-level potential vorticity disturbances and low-level disturbances. Favored theories of cyclones formation, however, focus on internal processes associated with cumulus convection and/or air-sea interaction. This work focuses on external mechanisms of cyclone formation and, using both a two- and three-dimensional moist geostrophic momentum model, investigates the role of upper-level potential vorticity disturbances on the formation process. A conceptual model of tropical cyclone formation is proposed, and implications of the theory are discussed. 71 refs., 5 figs., 1 tab.

Montgomery, M.T.; Farrell, B.F. (Harvard Univ., Cambridge, MA (United States))

1993-01-15

101

Lack of seroreactivity to Ehrlichia chaffeensis among rodent populations.  

PubMed

A retrospective serosurvey for antibodies to Ehrlichia chaffeensis was conducted on eight species of wild rodents (Mus musculus, Oryzomys palustris, Peromyscus leucopus, Rattus norvegicus, Reithrodontomys humulis, Sciurus carolinensis, Sciurus niger, and Sigmodon hispidus) from the southeastern United States. Serum samples (n = 281) collected between 1973 and 1993 were evaluated using an indirect fluorescent antibody test. All samples, screened at a dilution of 1:32, were negative for antibodies to E. chaffeensis. Sixty-three percent of the rodents tested were from areas where E. chaffeensis has been confirmed or is strongly suspected to be endemic. These data suggest limited or no involvement of rodents in the epidemiology of E. chaffeensis. PMID:9577793

Lockhart, J M; Davidson, W R; Stallknecht, D E; Dawson, J E

1998-04-01

102

Structural insights into the rodent CNS via diffusion tensor imaging  

PubMed Central

Diffusion tensor imaging (DTI) is a useful tool for studying anatomy and pathology in the rodent central nervous system (CNS).The unique tissue contrasts provided by DTI are well suited for monitoring disease progression, studying brain development, and characterizing anatomical phenotypes. Recent technical developments have vastly improved the speed and resolution of rodent DTI. Ongoing research efforts exploring the microstructural basis of DTI signals have provided useful insights into its capabilities to delineate brain structures and detect neuropathology. Significant progress has also been made in combining DTI results with data acquired using other imaging modalities to enhance our understanding of the rodent CNS. PMID:22651954

Zhang, Jiangyang; Aggarwal, Manisha; Mori, Susumu

2012-01-01

103

Data quality in predictive toxicology: reproducibility of rodent carcinogenicity experiments.  

PubMed Central

We compared 121 replicate rodent carcinogenicity assays from the two parts (National Cancer Institute/National Toxicology Program and literature) of the Carcinogenic Potency Database (CPDB) to estimate the reliability of these experiments. We estimated a concordance of 57% between the overall rodent carcinogenicity classifications from both sources. This value did not improve substantially when additional biologic information (species, sex, strain, target organs) was considered. These results indicate that rodent carcinogenicity assays are much less reproducible than previously expected, an effect that should be considered in the development of structure-activity relationship models and the risk assessment process. PMID:11401763

Gottmann, E; Kramer, S; Pfahringer, B; Helma, C

2001-01-01

104

Tropical Rainfall Measuring Mission  

NASA Technical Reports Server (NTRS)

Tropical rainfall affects the lives and economics of a majority of the Earth's population. Tropical rain systems, such as hurricanes, typhoons, and monsoons, are crucial to sustaining the livelihoods of those living in the tropics. Excess rainfall can cause floods and great property and crop damage, whereas too little rainfall can cause drought and crop failure. The latent heat release during the process of precipitation is a major source of energy that drives the atmospheric circulation. This latent heat can intensify weather systems, affecting weather thousands of kilometers away, thus making tropical rainfall an important indicator of atmospheric circulation and short-term climate change. Tropical forests and the underlying soils are major sources of many of the atmosphere's trace constituents. Together, the forests and the atmosphere act as a water-energy regulating system. Most of the rainfall is returned to the atmosphere through evaporation and transpiration, and the atmospheric trace constituents take part in the recycling process. Hence, the hydrological cycle provides a direct link between tropical rainfall and the global cycles of carbon, nitrogen, and sulfur, all important trace materials for the Earth's system. Because rainfall is such an important component in the interactions between the ocean, atmosphere, land, and the biosphere, accurate measurements of rainfall are crucial to understanding the workings of the Earth-atmosphere system. The large spatial and temporal variability of rainfall systems, however, poses a major challenge to estimating global rainfall. So far, there has been a lack of rain gauge networks, especially over the oceans, which points to satellite measurement as the only means by which global observation of rainfall can be made. The Tropical Rainfall Measuring Mission (TRMM), jointly sponsored by the National Aeronautics and Space Administration (NASA) of the United States and the National Space Development Agency (NASDA) of Japan, provides visible, infrared, and microwave observations of tropical and subtropical rain systems.The satellite observations are complemented by ground radar and rain gauge measurements to validate satellite rain estimation techniques. Goddard Space Flight Center's involvement includes the observatory, four instruments, integration and testing of the observatory, data processing and distribution, and satellite operations. TRMM has a design lifetime of three years. Data generated from TRMM and archived at the GDAAC are useful not only for hydrologists, atmospheric scientists, and climatologists, but also for the health community studying infectious diseases, the ocean research community, and the agricultural community.

1999-01-01

105

Transplantation and tropical infectious diseases  

Microsoft Academic Search

The number of transplant recipients with tropical infectious diseases is growing due to increasing international travel and the rising number of transplants taking place in the tropics and subtropics. With increases in population migration, the prevalence of individuals infected with geographically restricted organisms also rises. There are three potential categories of tropical infections in transplant patients: (1) donor-related infections transmitted

Carlos Franco-Paredes; Jesse T. Jacob; Alicia Hidron; Alfonso J. Rodriguez-Morales; David Kuhar; Angela M. Caliendo

2010-01-01

106

New Building, Old Parasite: Mesostigmatid Mites—An Ever-Present Threat to Barrier Rodent Facilities  

Microsoft Academic Search

Mesostigmatid mites are blood-sucking parasitic mites found in wild rodent populations. Periodically they can also become a problem for laboratory rodent colonies, particu- larly when building construction or renovations disturb colonies of commensal (building) rodents that had been act- ing as hosts. Mesostigmatid mites infest both rats and mice and, unlike the more common rodent fur mites (Myobia, Myocoptes, and

Julie Watson

107

RODENTICIDE USE IN RODENT MANAGEMENT IN THE UNITED STATES: AN OVERVIEW  

Microsoft Academic Search

Rodents occur worldwide and have adapted to most types of ecosystems. Rodents provide many important ecosystem functions and while most rodent species do not cause serious damage problems, a small number of species do. Rodent-caused damage includes crop and stored food consumption and contamination, forestry and nursery damage, rangeland damage, ornamental plant damage, property damage, cable and irrigation pipe damage,

GARY WITMER; JOHN D. EISEMANN

108

Swimming ability in three Costa Rican dry forest rodents  

E-print Network

We investigated the swimming abilities of three Costa Rican dry forest rodents (Coues' rice rat. Oryzomys couesi, hispid cotton rat, Sigmodon hispidus, and spiny pocket mouse, Liomys salvini) associated with a large marsh, ...

Cook, William M.; Timm, Robert M.; Hymen, Dena E.

2001-12-01

109

Cannabinoid-dependent plasticity in rodent somatosensory cortex.  

E-print Network

??Cortical long-term depression (LTD) and long-term potentiation (LTP) are thought to be important mechanisms for the plasticity of topographic sensory maps, especially in rodent somatosensory… (more)

Bender, Vanessa Anne

2006-01-01

110

Allocentric directional processing in the rodent and human retrosplenial cortex  

PubMed Central

Head direction (HD) cells in the rodent brain have been investigated for a number of years, providing us with a detailed understanding of how the rodent brain codes for allocentric direction. Allocentric direction refers to the orientation of the external environment, independent of one’s current (egocentric) orientation. The presence of neural activity related to allocentric directional coding in humans has also been noted but only recently directly tested. Given the current status of both fields, it seems beneficial to draw parallels between this rodent and human research. We therefore discuss how findings from the human retrosplenial cortex (RSC), including its “translational function” (converting egocentric to allocentric information) and ability to code for permanent objects, compare to findings from the rodent RSC. We conclude by suggesting critical future experiments that derive from a cross-species approach to understanding the function of the human RSC. PMID:24672459

Knight, Rebecca; Hayman, Robin

2014-01-01

111

A NEW METHOD TO QUANTIFY CORE TEMPERATURE INSTABILITY IN RODENTS.  

EPA Science Inventory

Methods to quantify instability of autonomic systems such as temperature regulation should be important in toxicant and drug safety studies. Stability of core temperature (Tc) in laboratory rodents is susceptible to a variety of stimuli. Calculating the temperature differential o...

112

Neural Representation of Spatial Topology in the Rodent Hippocampus  

E-print Network

Pyramidal cells in the rodent hippocampus often exhibit clear spatial tuning in navigation. Although it has been long suggested that pyramidal cell activity may underlie a topological code rather than a topographic code, ...

Chen, Zhe

113

Quantitative Ultrasound Assessment of HIFU Induced Lesions in Rodent Liver  

E-print Network

Quantitative Ultrasound Assessment of HIFU Induced Lesions in Rodent Liver Jeremy Kemmerer, Goutam Engineering University of Illinois at Urbana-Champaign Urbana, IL 61801 Email: kemmere1@illinois.edu Abstract

Illinois at Urbana-Champaign, University of

114

ASSESSMENT OF HOST RESISTANCE TO INFECTION WITH RODENT MALARIA  

EPA Science Inventory

Resistance to malaria infection is known to require an intact immune system. his chapter presents an overview of rodent malaria, the host response to infection and methods for assessing infection in rats and mice....

115

MEASUREMENT OF VENTILATORY FREQUENCY IN UNRESTRAINED RODENTS USING MICROWAVE RADIATION  

EPA Science Inventory

A novel technique for remote determination of breathing frequency in unrestrained rodents using microwave radiation is described. Single mice were placed inside a rectangular waveguide operating at 2450 MHz. Because mice efficiently absorb radio frequency energy at 2450 MHz, any ...

116

Ejaculate investment in a promiscuous rodent, Peromyscus maniculatus: effects of  

E-print Network

Ejaculate investment in a promiscuous rodent, Peromyscus maniculatus: effects of population density, somatic mass and annual population density for wild-caught male deer mice, Peromyscus maniculatus rank. Keywords: ejaculate investment, mating system, Peromyscus maniculatus, population density, sexual

Montgomerie, Bob

117

Tropical Limit in Statistical Physics  

E-print Network

Tropical limit for macroscopic systems in equilibrium defined as the formal limit of Boltzmann constant k going to 0 is discussed. It is shown that such tropical limit is well-adapted to analyse properties of systems with highly degenerated energy levels, particularly of frustrated systems like spin ice and spin glasses. Tropical free energy is a piecewise linear function of temperature, tropical entropy is a piecewise constant function and the system has energy for which tropical Gibbs' probability has maximum. Properties of systems in the points of jump of entropy are studied. Systems with finite and infinitely many energy levels and phenomena of limiting temperatures are discussed.

M. Angelelli; B. Konopelchenko

2015-02-04

118

People & Tropical Rain Forests.  

ERIC Educational Resources Information Center

Discusses ways people who live in rain forests make a living and some of the products that enrich our lives. Provides activities covering forest people, tropical treats, jungle in the pantry, treetop explorers, and three copyable pages to accompany activities. (Author/RT)

NatureScope, 1989

1989-01-01

119

Rain Forests: Tropical Treasures.  

ERIC Educational Resources Information Center

Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Rain Forests: Tropical Treasures." Contents are organized into the following…

Braus, Judy, Ed.

1989-01-01

120

Tropical Atlantic Aerosols  

NSDL National Science Digital Library

Students will use real satellite data to determine 1) where the greatest concentrations of aerosols are located during the course of a year in the tropical Atlantic region and 2) their source of origin. This is an inquiry-style lesson where students pull real aerosol data and attempt to identify trends among data sets.

Roettger, Rex; Collection, Nasa -.

121

Secondary dispersal of Dioscorea japonica (Dioscoreaceae) bulbils by rodents  

Microsoft Academic Search

We examined rodent dispersal of Dioscorea japonica bulbils. Bulbils dispersed by rodents may travel farther from their parent plants than those dispersed by gravity alone.\\u000a To confirm the presence of secondary dispersal and the types of vector, we used an automatic camera to photograph animals\\u000a that approached bulbils. To clarify secondary dispersal distance, we set marked bulbils at eight sites

Inoue Mizuki; Akiko Takahashi

2009-01-01

122

Findings of mycobacteria in insectivores and small rodents  

Microsoft Academic Search

The organs of 30 insectivorous mammals and 62 rodents from areas inhabited by people or livestock where cattle paratuberculosis\\u000a or mycobacterial infections of swine had been found to occur were examined by cultivation during the monitoring of occurrence\\u000a and spread of mycobacterioses in cattle and swine. Mycobacteria were found in the organs of 3 insectivores (10%) and 6 rodents\\u000a (9.7%).Mycobacterium

O. Fischer; L. Mátlová; J. Bartl; L. Dvorská; I. Melichárek; I. Pavlík

2000-01-01

123

Zoonotic helminthes of commensal rodents in Talkha Center, Dakahlia Governorate.  

PubMed

Commensal rodents were trapped alive from different areas near garbage, canal edges, farm animals and the likes in Talkha Center over one year. A total of 135 rodents were collected, their species and index were Rattus norvegicus (0.11), R. r. frugivorous (0.13), R. r. alexandrinus (0.16) and Mus musculus (0.5). The zoonotic helminthes were trematodes (10 species), cestodes (4 species), and nematodes (10 species). The results were discussed on light of other works. PMID:19209769

El Kady, Gamal A; Gheneam, Yousr Mosleh; Bahgat, Iman M

2008-12-01

124

Divergent patterns of breakpoint reuse in Muroid rodents.  

PubMed

Multiple Genome Rearrangement (MGR) analysis was used to define the trajectory and pattern of chromosome rearrangement within muroid rodents. MGR was applied using 107 chromosome homologies between Mus, Rattus, Peromyscus, the muroid sister taxon Cricetulus griseus, and Sciurus carolinensis as a non-Muroidea outgroup, with specific attention paid to breakpoint reuse and centromere evolution. This analysis revealed a high level of chromosome breakpoint conservation between Rattus and Peromyscus and indicated that the chromosomes of Mus are highly derived. This analysis identified several conserved evolutionary breakpoints that have been reused multiple times during karyotypic evolution in rodents. Our data demonstrate a high level of reuse of breakpoints among muroid rodents, further supporting the "Fragile Breakage Model" of chromosome evolution. We provide the first analysis of rodent centromeres with respect to evolutionary breakpoints. By analyzing closely related rodent species we were able to clarify muroid rodent karyotypic evolution. We were also able to derive several high-resolution ancestral karyotypes and identify rearrangements specific to various stages of Muroidea evolution. These data were useful in further characterizing lineage-specific modes of chromosome evolution. PMID:20033182

Mlynarski, E E; Obergfell, C J; O'Neill, M J; O'Neill, R J

2010-02-01

125

Navigating actions through the rodent parietal cortex  

PubMed Central

The posterior parietal cortex (PPC) participates in a manifold of cognitive functions, including visual attention, working memory, spatial processing, and movement planning. Given the vast interconnectivity of PPC with sensory and motor areas, it is not surprising that neuronal recordings show that PPC often encodes mixtures of spatial information as well as the movements required to reach a goal. Recent work sought to discern the relative strength of spatial vs. motor signaling in PPC by recording single unit activity in PPC of freely behaving rats during selective changes in either the spatial layout of the local environment or in the pattern of locomotor behaviors executed during navigational tasks. The results revealed unequivocally a predominant sensitivity of PPC neurons to locomotor action structure, with subsets of cells even encoding upcoming movements more than 1 s in advance. In light of these and other recent findings in the field, I propose that one of the key contributions of PPC to navigation is the synthesis of goal-directed behavioral sequences, and that the rodent PPC may serve as an apt system to investigate cellular mechanisms for spatial motor planning as traditionally studied in humans and monkeys. PMID:24860475

Whitlock, Jonathan R.

2014-01-01

126

Assessing Spatial Learning and Memory in Rodents  

PubMed Central

Maneuvering safely through the environment is central to survival of almost all species. The ability to do this depends on learning and remembering locations. This capacity is encoded in the brain by two systems: one using cues outside the organism (distal cues), allocentric navigation, and one using self-movement, internal cues and nearby proximal cues, egocentric navigation. Allocentric navigation involves the hippocampus, entorhinal cortex, and surrounding structures; in humans this system encodes allocentric, semantic, and episodic memory. This form of memory is assessed in laboratory animals in many ways, but the dominant form of assessment is the Morris water maze (MWM). Egocentric navigation involves the dorsal striatum and connected structures; in humans this system encodes routes and integrated paths and, when overlearned, becomes procedural memory. In this article, several allocentric assessment methods for rodents are reviewed and compared with the MWM. MWM advantages (little training required, no food deprivation, ease of testing, rapid and reliable learning, insensitivity to differences in body weight and appetite, absence of nonperformers, control methods for proximal cue learning, and performance effects) and disadvantages (concern about stress, perhaps not as sensitive for working memory) are discussed. Evidence-based design improvements and testing methods are reviewed for both rats and mice. Experimental factors that apply generally to spatial navigation and to MWM specifically are considered. It is concluded that, on balance, the MWM has more advantages than disadvantages and compares favorably with other allocentric navigation tasks. PMID:25225309

Vorhees, Charles V.; Williams, Michael T.

2014-01-01

127

Mother–Pup Interactions: Rodents and Humans  

PubMed Central

In order to survive after birth, mammalian infants need a caretaker, usually the mother. Several behavioral strategies have evolved to guarantee the transition from a period of intense caregiving to offspring independence. Here, we examine a selection of literature on the genetic, epigenetic, physiological, and behavioral factors relating to development and mother–infant interactions. We intend to show the utility of comparisons between rodent and human models for deepening knowledge regarding this key relationship. Particular attention is paid to the following factors: the distinct developmental stages of the mother–pup relationship as relating to behavior; examples of key genetic components of mammalian mother–infant interactions, specifically those coding for the hormones oxytocin and vasopressin; and the possible functions of gene imprinting in mediating interactions between genetics and environment in the mother–infant relationship. As early mother–infant attachment seems to establish the basic parameters for later social interactions, ongoing investigations in this area are essential. We propose the importance of interdisciplinary collaboration in order to better understand the network of genes, gene regulation, neuropeptide action, physiological processes, and feedback loops essential to understand the complex behaviors of mother–infant interaction. PMID:24616713

Lucion, Aldo B.; Bortolini, Maria Cátira

2014-01-01

128

Interval eigenproblem in tropical and fuzzy algebra Tolerance eigenproblem in tropical algebra  

E-print Network

Interval eigenproblem in tropical and fuzzy algebra Tolerance eigenproblem in tropical algebra Tolerance eigenproblem in fuzzy algebra Tolerance interval eigenvectors in tropical and fuzzy algebra Martin Workshop Birmingham, May 16, 2013 #12;Interval eigenproblem in tropical and fuzzy algebra Tolerance

Mitchener, Paul

129

Partial Rodent Genetic Models for Bipolar Disorder  

PubMed Central

Bipolar disorder (BPD) is a complex clinical phenomenon. This episodic illness comprises at least four features/components: depression, mania, vulnerability to mood swings in euthymic BPD patients, and spontaneous cyclicity in at least some BPD patients. Currently, there is no rodent genetic model capable of encompassing the whole phenotype of BPD exists; however, recent genetic-behavioral studies have delineated partial models for some components of BPD, namely, depression, mania, and vulnerability or resilience to mood swings. p11 knockout (KO), vesicular monoamine transporter 2 (VMAT2) heterozygous KO, and neural cell adhesion molecule (NCAM) KO mice display anhedonia-like symptoms, and treatment with antidepressants rescues this anhedonia-related phenotype. Mutant CLOCK, glutamate receptor 6 (GluR6) KO, and extracellular signal-regulated kinase 1 (ERK1) KO mice exhibit mania-like behavioral clusters referred to as excessive behavioral excitement; at least some of the exhibited behaviors can be rescued through treatment with mood stabilizers or atypical antipsychotics. Neuronal glucocorticoid receptor (GR) overexpressing, B-cell lymphoma 2 (Bcl-2) heterozygous KO, and Bcl-2-associated athanogene (BAG1) heterozygous KO mice show vulnerability to mood swings. In contrast, neuronal BAG1 overexpressing mice display resilience to mood swings. These mutant mouse strains and the behavioral approaches used to characterize these strains offer an emerging set of research tools for the comprehensive understanding of various components of BPD, and the interrelation of these components at the molecular, cellular, and neuronal circuitry levels. These partial genetic models can also be used as complementary tools to augment other existing behavioral tests and paradigms in drug development for BPD. PMID:25236551

Chen, Guang; Henter, Ioline D.; Manji, Husseini K.

2015-01-01

130

Tropical Curves and Amoebas Jan Verschelde  

E-print Network

Tropical Curves and Amoebas Jan Verschelde University of Illinois at Chicago Department Computational Algebraic Geometry Seminar Jan Verschelde (UIC) Tropical Curves and Amoebas 23 January 2014 1 / 26 #12;Tropical Curves and Amoebas 1 Introduction Introduction to Tropical Geometry 2 Tropical Curves

Verschelde, Jan

131

Tropical ecotoxicology: The state of the environment in the tropics  

SciTech Connect

Ecotoxicology has focused almost exclusively on temperate zone countries and ecosystems. Tropical ecosystems, including rain forest, tropical dry forest, savanna, wetlands and freshwater ecosystems, have been neglected. These ecosystems combined might contain as much as 75% of global biodiversity. Tropical ecosystems are under increasing threat of development and alteration. The major causes of habitat degradation in the tropics include population growth and urbanization, agricultural expansion, deforestation, and mining. Some of these activities (in particular agriculture, mining, and the manufacturing and chemical industries) also lead to the release of toxic substances into the environment. Little research in ecotoxicology has been done in tropical environments and techniques and procedures developed for temperate environments are often applied, even though physical and chemical environmental parameters in the tropics can be very different. The regulatory environment also varies from country to country. The authors present an extensive literature review of tropical ecotoxicology, with a focus on Latin America and the Caribbean. Most research has focused on water quality and aquatic toxicology. Virtually no research has been done on the effects of toxic substance on tropical wildlife. They present a protocol for tropical ecotoxicology that addresses the special problems associated with doing ecotoxicological research in the tropics. The authors discuss the issue of adapting temperate zone principles and methods to tropical environments. Finally, they discuss priority areas for immediate research. These include large scale agricultural activities, especially bananas, pineapples, and soybeans and gold mining with the associated heavy use of mercury. The authors also present a prioritization of tropical wildlife that appear to be at highest risk of exposure to toxic substances.

Lacher, T.E. Jr. [Archbold Tropical Research Center, Clemson, SC (United States); [Inst. of Wildlife and Environmental Toxicology, Pendleton, SC (United States); Goldstein, M.I. [Inst. of Wildlife and Environmental Toxicology, Pendleton, SC (United States)

1995-12-31

132

Student Research, Tropical Style!  

NSDL National Science Digital Library

A field trip to a tropical location is used to help students examine the process of scientific research. Each student designs a research project, compiles background material, develops the procedure, and builds, buys, or acquires the necessary equipment. A field study trip to a tropical location allows them to collect their data, while demonstrating that science can be interesting and fun! Conclusions are drawn and the final paper is drafted and submitted several weeks after their return. The main area of concentration is marine ecology, but usually each year an additional research topic is offered depending on the location of the field study. One semester of elective high school science credit is awarded for each year. College credit is also offered.

Monte Morris (Clark County R-1 High School REV)

1995-06-30

133

Tropical fevers: Management guidelines  

PubMed Central

Tropical fevers were defined as infections that are prevalent in, or are unique to tropical and subtropical regions. Some of these occur throughout the year and some especially in rainy and post-rainy season. Concerned about high prevalence and morbidity and mortality caused by these infections, and overlapping clinical presentations, difficulties in arriving at specific diagnoses and need for early empiric treatment, Indian Society of Critical Care Medicine (ISCCM) constituted an expert committee to develop a consensus statement and guidelines for management of these diseases in the emergency and critical care. The committee decided to focus on most common infections on the basis of available epidemiologic data from India and overall experience of the group. These included dengue hemorrhagic fever, rickettsial infections/scrub typhus, malaria (usually falciparum), typhoid, and leptospira bacterial sepsis and common viral infections like influenza. The committee recommends a ‘syndromic approach’ to diagnosis and treatment of critical tropical infections and has identified five major clinical syndromes: undifferentiated fever, fever with rash / thrombocytopenia, fever with acute respiratory distress syndrome (ARDS), fever with encephalopathy and fever with multi organ dysfunction syndrome. Evidence based algorithms are presented to guide critical care specialists to choose reliable rapid diagnostic modalities and early empiric therapy based on clinical syndromes. PMID:24678147

Singhi, Sunit; Chaudhary, Dhruva; Varghese, George M.; Bhalla, Ashish; Karthi, N.; Kalantri, S.; Peter, J. V.; Mishra, Rajesh; Bhagchandani, Rajesh; Munjal, M.; Chugh, T. D.; Rungta, Narendra

2014-01-01

134

GPM: Hurricanes Beyond the Tropics  

NSDL National Science Digital Library

When New England was hit by Tropical Storm Irene in 2011, there was not a satellite monitoring tropical storms that far north; the Tropical Rainfall Measuring Mission (TRMM) was operating in a band between the 35-degree latitudes. The Global Precipitation Measurement (GPM) mission will change that. GPM will build upon TRMM's capacity by examining a larger swath of Earth with instruments that are more advanced and more sensitive. This video introduces the GPM satellite, its instruments and their capabilities.

135

Tropical disturbances in a GCM  

Microsoft Academic Search

We have analyzed the tropical disturbances in a 11-layer atmospheric general circulation model (GCM) on a 2.5° × 3.75° horizontal grid coupled to a 50 m-mixed layer ocean. Due to the coarse resolution, the GCM is unable to resolve adequately tropical cyclones. The tropical disturbances simulated by the GCM are much weaker and have a much larger horizontal extent. However,

R J Haarsma; J F B Mitchell; C A Senior

1993-01-01

136

Fibroblasts from long-lived rodent species exclude cadmium.  

PubMed

Resistance to the lethal effects of cellular stressors, including the toxic heavy metal cadmium (Cd), is characteristic of fibroblast cell lines derived from long-lived bird and rodent species, as well as cell lines from several varieties of long-lived mutant mice. To explore the mechanism of resistance to Cd, we used inductively coupled plasma mass spectroscopy to measure the rate of Cd uptake into primary fibroblasts of 15 rodent species. These data indicate that fibroblasts from long-lived rodent species have slower rates of Cd uptake from the extracellular medium than those from short-lived species. In addition, fibroblasts from short-lived species export more zinc after exposure to extracellular Cd than cells from long-lived species. Lastly, fibroblasts from long-lived rodent species have lower baseline concentrations of two redox-active metals, iron and copper. Our results suggest that evolution of longevity among rodents required adjustment of cellular properties to alter metal homeostasis and to reduce the toxic effects of heavy metals that accumulate over the course of a longer life span. PMID:24522391

Dostál, Lubomír; Kohler, William M; Penner-Hahn, James E; Miller, Richard A; Fierke, Carol A

2015-01-01

137

Effects of Lersivirine on Canine and Rodent Thyroid Function.  

PubMed

Lersivirine is a nonnucleoside reverse transcriptase inhibitor (NNRTI) being developed for the treatment of HIV-1 infection. Like other NNRTIs, lersivirine is a potent enzyme inducer in rodents capable of inducing a number of hepatic enzymes including those involved in its own metabolism. Preclinically lersivirine has been associated with hepatocellular hypertrophy and thyroid gland follicular cell hypertrophy in rats, mice, and dogs. In rodents, we show that development of thyroid hypertrophy is related to the classic mechanism, namely increased thyroxine (T4) clearance secondary to induction of uridine-diphosphoglucuronosyltransferase (UDPGT) in the liver and a resulting increase in thyroid-stimulating hormone. Similarly, lersivirine-exposed dogs exhibit a significant increase in hepatic UDPGT enzyme activity along with increased T4 clearance although clear effects on serum thyroid hormone levels were less apparent. These effects on thyroid hormonal clearance in the dog suggest that thyroid gland hypertrophy in this species is due to the same mechanism shown to occur in rodents although, as expected, dogs better adapt to these effects and therefore maintain relatively normal thyroid hormonal balance. It is also notable that the minimal thyroid follicular hypertrophy that occurs in dogs does not progress as is seen in rodents. As is the case with rodents, these adaptive changes in the dog are not considered indicative of a human health risk. PMID:24135463

Houle, Christopher D; Finch, Gregory L; Mauthe, Robert J; Potter, David M; Walisser, Jacqueline A; Gardner, Iain B; DeWit, Robert H

2013-10-16

138

Ectoparasites of commensal rodents in Talkha Center, Dakahlia Governorate, Egypt.  

PubMed

The ecto-parasites infesting commensally rodents were collected from the different localities in Talkha Center (Dakahlia Governorate) from April 2006 to March 2007. The seasonal abundance of rodent number and rat index was 52 (0.58) in spring, 27 (0.3) in summer, 39 (0.22) in autumn and 17 (0.05) in winter. From 135 rodent species and rat index was Rattus norvegicus N=33 (0.24), R. r. frugivorous N=39 (0.29); R. r. alexandrinus N=48 (0.36) and Mus musculus N=15 (0.11). From 388 ecto-parasite infested rodent collected number and ecto index was fleas N= 114 (0.84 flea/rat), Lice N=93 (0.69 lice/rat), Mites N = 165 (1.2 mite/rat) and larva of ticks N=16 (0.12 tick/rat). No doubt, rodents and their ectoparasites played a serious role in spreading and transmission of zoonotic diseases to human and animal. PMID:18383784

El Kady, Gamal A; El Shazly, Atef M; Mikhail, Micheal W; Bahgat, Iman M

2007-12-01

139

Hypergravity Effects on Rodent Pregnancy and Parturition  

NASA Technical Reports Server (NTRS)

No mammal has yet undergone birth, or parturition, in the microgravity of space. Previous studies (Ronco & Alberts, 2000) have shown that mid-pregnant rat dams exposed to spaceflight (0-g) and landed 48-72 hrs before term successfully delivered robust, healthy offspring Microgravity-exposed dams exhibited twice the expected numbers of labor contractions whereas length of pregnancy, duration of labor, fetal wastage, number of neonates born and litter gender ratios were identical to controls. In the present study, we report the results of rodent pregnancy and parturition at the opposite end of the gravity spectrum, in hypergravity. Dams exposed to either: 1.0-g, 1.5-g, 1.75-g or 2.0-g from Gestational day (G) 11 and throughout the births of their litters had comparable pregnancy and labor durations, fetal wastage, numbers of neonates born and litter Tender ratios. During parturition, hypergravity-exposed dams exhibited significantly fewer labor contractions as compared to 1.0-g controls. Dams that underwent birth in hypergravity had significantly fewer offspring surviving the immediate postpartum period (P1: 1.0-g, 11.92 +/- 2.84; 1.5-g, 10.88 +/- 2.17; 1.75-g, 9.22 +/-1.99; 2.0-g, 8.83 +/- 3.31). Within 24 hrs postpartum, neonatal survival was further diminished in hypergravity [P2: 100% (1.0-g); 96% (1.5-g); 96% (1.75-g); 73% (2.0-g)] and continued to decline (P10: 100%(1.0-g.); 90%(1.5-g); 87%(1.75-g), 40%(2.0-g)]. Neonatal losses stabilized by P5 for the 1.5-g andl.75-g conditions but continued until P9 for the 2.0-g condition. Together, these findings show that postnatal, but not prenatal, survival is compromised following birth in hypergravity, Maternal and neonatal factors that contribute to peri-parturitional vulnerability to altered gravity environments will be discussed.

Ronca, A. E.; Baer, L. A.; Mills, N. A.; Wade, C. E.; Dalton, Bonnie (Technical Monitor)

2002-01-01

140

Rodents for comparative aging studies: from mice to beavers  

PubMed Central

After humans, mice are the best-studied mammalian species in terms of their biology and genetics. Gerontological research has used mice and rats extensively to generate short- and long-lived mutants, study caloric restriction and more. Mice and rats are valuable model organisms thanks to their small size, short lifespans and fast reproduction. However, when the goal is to further extend the already long human lifespan, studying fast aging species may not provide all the answers. Remarkably, in addition to the fast-aging species, the order Rodentia contains multiple long-lived species with lifespans exceeding 20 years (naked mole-rat, beavers, porcupines, and some squirrels). This diversity opens great opportunities for comparative aging studies. Here we discuss the evolution of lifespan in rodents, review the biology of slow-aging rodents, and show an example of how the use of a comparative approach revealed that telomerase activity coevolved with body mass in rodents. PMID:19424861

Bozzella, Michael J.; Seluanov, Andrei

2008-01-01

141

A Standardized Technique for Performing Thrombelastography in Rodents  

PubMed Central

Introduction Thrombelastography (TEG), employed in liver transplant and cardiac surgery for nearly 50 years, has recently been applied to the trauma setting. Rodents are employed widely for shock research, but are known to have differences in their coagulation system compared to humans. Consequently, the appropriate technique for performing TEG requires modification of the standard clinical protocol. Materials and Methods Thrombelastography (TEG) was performed with blood collected from the femoral artery of rodents, and technical modifications were tested to optimize results. Results Analysis of citrated whole blood using TEG revealed a more rapid onset of coagulation in rats compared to humans. The reference ranges of TEG parameters for Sprague-Dawley rats are detailed. Discussion Citrated native whole blood is the optimal TEG method in the assessment of coagulation in rodents. Investigators using TEG for research purposes should establish their own reference ranges in order to determine normal values for their target population. PMID:22005752

Wohlauer, Max V.; Moore, Ernest E.; Harr, Jeffrey; Gonzalez, Eduardo; Fragoso, Miguel; Silliman, Christopher C.

2011-01-01

142

Unexpected primitive rodents in the Quaternary of Argentina  

NASA Astrophysics Data System (ADS)

This article describes the first fossils recorded in the Hernandarias Formation (Pleistocene) in Entre Ríos province (eastern Argentina). They are represented by three teeth assigned to the caviomorph rodents (Rodentia, Mammalia) Aenigmys diamantensis gen. et sp. nov. and Eumysops. To establish the phylogenetic affinities of the two most enigmatic teeth, their enamel microstructure was studied. Aenigmys diamantensis is considered the most primitive taxon of a clade formed by Dinomyidae-Neoepiblemidae-Heptaxodontidae. Evidence of the close relationships among these families also is presented herein. The new fossils reinforce previous hypotheses about the survival of primitive Brazilian taxa after their extinction in the Pampas and Patagonia of southern South America. They also show that the diversity of caviomorph rodents during the Quaternary was greater than supposed and that an important Quaternary extinction, not previously detected, affected several lineages. With the available evidence, it is not possible to determine if these rodents indicate a warm pulse or a particular biogeographic situation in Entre Ríos.

Vucetich, María G.; Vieytes, Emma C.; Verzi, Diego H.; Noriega, Jorge I.; Tonni, Eduardo P.

2005-10-01

143

A Tropical Cyclone Genesis Parameter for the Tropical Atlantic  

Microsoft Academic Search

A parameter to evaluate the potential for tropical cyclone formation (genesis) in the North Atlantic between Africa and the Caribbean islands is developed. Climatologically, this region is the source of about 40% of the Atlantic basin tropical cyclones but roughly 60% of the major hurricanes. The genesis parameter is the product of appropriately scaled 5-day running mean vertical shear, vertical

Mark DeMaria; John A. Knaff; Bernadette H. Connell

2001-01-01

144

Fairchild Tropical Botanic Garden 74 FAIRCHILD TROPICAL BOTANIC GARDEN  

E-print Network

's resources to study the nature of four biomes that occur throughout the tropics (a biome is a climatically in the garden have been collected from wild habitats, such as forests, from throughout the tropics. The garden plant family), cacti (only from rain forests of the New World), and orchids. Or- chids, or members

Koptur, Suzanne

145

Synanthropic rodents as possible reservoirs of shigatoxigenic Escherichia coli strains  

PubMed Central

Shigatoxigenic Escherichia coli (STEC) strains are worldwide zoonotic pathogen responsible for different cases of human disease including hemolytic uremic syndrome (HUS). Transmission of STEC to humans occurs through the consumption of food and water contaminated by faeces of carriers and by person-to-person contact. The objective of this study was two-fold: (1) to investigate whether synanthropic rodents are possible reservoirs of STEC in the urban area and (2) whether a particular genus out of synanthropic rodent is the principal carrier of STEC. One hundred and forty-five rodents were captured in Buenos Aires City. Screening for stx1/stx2 and rfbO157 was done by PCR from the confluence zone. STEC isolates were further characterized with biochemical tests by standard methods. Additional virulence factors (eae, ehxA, and saa) were also determined by PCR. Forty-one of the rodents were necropsied and sample of kidney and small and large intestine were taken for histopathological diagnosis. The samples sections were stained with hematoxylin-eosin, and observed by light microscopy to evaluate the systemic involvement of these species in natural infections. STEC was isolated from seven out of 27 suspect animals at screening. The following genotypes were found in the STEC strains: stx1/stx2/ehxA (1), stx2 (4), stx2/ehxA (1), stx2/ehxA/eae (1). Neither gross nor microscopic lesions compatible with those produced by Shiga toxin were observed in the studied organs of necropsied rodents. The bivariate analysis including the 145 rodent's data showed that the isolation of STEC is associated positively to Rattus genus. This synanthropic species may play a role in the transmissibility of the agent thus being a risk to the susceptible population. Their control should be included specifically in actions to dismiss the contamination of food and water by STEC in the urban area, as additional strategies for epidemiological control. PMID:23125967

Blanco Crivelli, Ximena; Rumi, María V.; Carfagnini, Julio C.; Degregorio, Osvaldo; Bentancor, Adriana B.

2012-01-01

146

European Cloth and “Tropical” Skin:  

PubMed Central

As Britain’s imperial and colonial ambitions intensified toward the end of the nineteenth century, the preservation of white European health in tropical climates became an increasingly important concern. Since at least the seventeenth century, the “tropics” had been seen as spaces holding vast potential wealth but also death and disease. To combat these deadly but desirable landscapes, the British built a considerable commodity culture around the preservation of white European health, and for many, tropical clothing was one of the most important and essential items in their “kits.” This article investigates the composition and use of such clothing in relation to British ideas of health and hygiene in tropical climates. First, it considers debates that ensued over the best material—wool, cotton, linen, silk, or a combination of these materials—and the role of “black” skin and local practice in the development of tropical clothing. Second, it demonstrates the importance of location in any discussion of tropical medicine and hygiene, and the tension and ambiguity that still surrounded British ideas of health and hygiene in the tropical colonies. Third, it argues that tropical clothing was important in the maintenance of climatic etiologies despite advances in parasitology and sanitary science. Finally, it considers the relationship of tropical clothing to the formation of a unique colonial identity. To British men and women embarking for any number of tropical destinations, proper clothing was not a banal and mundane component of their outfitting. For many, the clothing signified a departure from the safe and “civil” climes of Britain for adventure in the expanding tropical empire. PMID:19801795

Johnson, Ryan

2009-01-01

147

Aerobic and anaerobic metabolism during activity in small rodents.  

PubMed

Analysis of oxygen consumption and lactic acid formation during five minutes of maximal activity by the rodents Microtus montanus (Cricetidae) and Dipodomys merriami (Hetermyidae) indicates that: (1) anaerobiosis provides approximately 10% of total energy utilized during the 5-minute activity period; (2) anaerobiosis may account for as much as one-third of total energy utilized during the first 30 seconds of activity. In addition, these data indicate at least one species of lizard may be capable of a higher total rate of metabolism during "burst" activity than are the rodents investigated here. PMID:381568

Ruben, J A; Battalia, D E

1979-04-01

148

Adiaspiromycosis of an Apodemus agrarius captured wild rodent in Korea  

PubMed Central

Adiaspiromycosis is caused by pulmonary infection with Emmonsia. Inhalated spores of Emmonsia cause asymptomatic infection to necrogranulomatous pneumonia, depending on the burden of adiaspore and host immunity. For disease monitoring of wild rodents captured on Jeju Island in Korea, we examined the lung tissue of wild rodents histopathologically. Spores composed of thick three-layered walls were found following histopathological examination and were diagnosed as adiaspiromycosis. Adiaspiromycosis has been found in mammals in many parts of the world. To our knowledge, this is the first report of adiaspiromycosis of an Apodemus agrarius captured in Korea. PMID:22474477

Kim, Tae-Hyoun; Han, Ju-Hee; Chang, Seo-Na; Kim, Dong-Su; Abdelkader, Tamer Said; Seok, Seung-Hyeok; Park, Jong-Hwan; Oh, Hong-Shik; Kim, Jong-Taek; Lee, Byoung-Hee; Shin, Jeong-Hwa; Kim, Jung-Hyun; Kim, Jong-Min

2012-01-01

149

Desert-Tropicals.com  

NSDL National Science Digital Library

Created by plant enthusiast Philippe Faucon, Desert-Tropicals.com is a well-designed website with information about, and pictures of, over 3,500 plants. Plant lists are organized by scientific and common name, succulents, xeriscape plants, palm trees, herbs, and trees. The plant lists are quite extensive, and each species receives its own description page with a nice close-up photo as well as brief information about family, frost and heat tolerance, sun exposure, origin, propagation, and more. The site also connects to articles, a Bulletin Board, Bookstore, and relevant links.

Faucon, Philippe

150

Tropical Cyclone Intensity Analysis  

NSDL National Science Digital Library

This lesson provides guidance for operational forecasters needing to combine different intensity methods to determine the intensity of a tropical cyclone. Each of the intensity methods is summarized, focusing on both strengths and weaknesses. These methods include the Dvorak technique, surface observations, scatterometry, the Advanced Dvorak Technique (ADT), microwave sounders (AMSU), SATCON, and subjective interpretation of passive microwave patterns. Consideration of the previous intensity estimate and forecast is also examined. Three case studies task the learner with combining the various methods to derive appropriate intensity estimates and a final quiz tests learner knowledge to demonstrate successful completion of the lesson.

Comet

2014-05-15

151

Prevalence and diversity of Bartonella in rodents of northern Thailand: a comparison with Bartonella in rodents from southern China.  

PubMed

We report results of the first study to investigate the distribution and diversity of Bartonella in rodents from Thailand. Whole blood from 195 rodents, representing six species, was tested for the presence of Bartonella species using standard culture techniques. Isolates were obtained from 17 (8.7%) of the samples, and 14 of those isolates represented distinct strains, based upon partial sequencing of the citrate synthase (gltA) gene. Phylogenetic analysis of the isolates and other Bartonella species indicated that five unique isolates from Bandicota indica form a cluster that may represent a new Bartonella species. Two additional isolates from B. indica clustered together, and were nearly identical to an isolate from Apodemus draco collected in southern China. Importantly, a number of the isolates from Thailand rodents are closely related to B. grahamii and B. elizabethae, species which have been associated with human illness. PMID:15100459

Castle, Kevin T; Kosoy, Michael; Lerdthusnee, Kriangkrai; Phelan, Lori; Bai, Ying; Gage, Kenneth L; Leepitakrat, Warisa; Monkanna, Taweesak; Khlaimanee, Nittaya; Chandranoi, Kirkvich; Jones, James W; Coleman, Russell E

2004-04-01

152

Neighbourhood analyses of tree seed predation by introduced rodents in a New Zealand temperate rainforest  

E-print Network

mice Mus musculus and other introduced rodents represent a novel source of predation on tree seeds have important implications for tree population dynamics. Introduced rodents Á house mice Mus musculus

153

[Foot health in the tropics].  

PubMed

The foot is particularly exposed to injury and infection in the tropical areas. This article provides a review of the main diseases affecting the foot in the tropics including leprosy, ainhum, ulceration due to Mycobacterium ulcerans, mycetoma, chromomycosis, Kaposi's sarcoma, elephantiasis, podoconiasis, dracunculosis, tungiasis, syphilis and endemic treponematosis, larva migrans, scytalidiosis, and envenomation. Prevention is essential. PMID:18630042

Morand, J J

2008-04-01

154

Combating tropical deforestation in Haiti  

SciTech Connect

This article outlines the findings of Tropical Forestry Action Plan (TFAP), which was part of an international initiative on tropical deforestation. Ten specific recommendations are addressed. Haiti has lost more than 97% of its forestland, so emphasis should be placed on replenishing the forest cover.

Pellek, R.

1990-09-01

155

Climatic Variability In Tropical Countries  

Microsoft Academic Search

Introduction Droughts in tropical countries are proved as periodic and its occurrence is shown remarkable in 9.25 year cycles as explained by the author. These cycles exist as soon or late around the central point. In the tropical regions monsoons or trade winds has a definite origin and pattern of advancing towards land mass. Ocean evaporation is the main source

L. W. Seneviratne

2003-01-01

156

Tropical Rainforest Education. ERIC Digest.  

ERIC Educational Resources Information Center

This digest provides four guideposts for tropical rainforest education: (1) structure; (2) location and climate; (3) importance; and (4) conservation of resources. Research is cited and background information provided about the layers of life and the adaptations of life within the tropical rain forest. Aspects of life within and near rain forests…

Rillero, Peter

157

Hurricanes and Tropical Meteorology Background  

E-print Network

- 1 - Hurricanes and Tropical Meteorology Background: Over the last 20 years, hurricane research at AOML has focused on improved scientific understanding of hurricanes and of tropical meteorology scientific goals for AOMLs hurricane research derive from the U.S. Weather Research Programs (USWRP

158

Tropical Synoptic Meteorology Curriculum Package  

NSDL National Science Digital Library

The Tropical Synoptic Meteorology Curriculum Package is a university-level, online meteorology course package. It is freely available to interested institutions that are expanding their course offerings, particularly their online offerings. The course fulfills the synoptic and mesoscale meteorology requirements for the World Meteorological Organization (WMO) Basic Instruction Package for Meteorology (BIP-M), but with an emphasis on the tropics to provide focus for those working or planning to work in tropical regions. The course utilizes existing and newly developed resources, including the online textbook, Introduction to Tropical Meteorology (http://www.meted.ucar.edu/tropical/textbook_2nd_edition/). The course package includes an instructor’s guide and model syllabus with learning objectives, free online instructional resources, introductory slides for faculty use, case examples, questions for review or discussion, student assignments, quizzes, learning activities, and guidance for online course delivery. All materials are made available in Google Docs format for downloading and customizing.

COMET

2013-08-06

159

Tropical chronic pancreatitis.  

PubMed

Tropical chronic pancreatitis (TCP) is a juvenile form of chronic calcific non-alcoholic pancreatitis, seen almost exclusively in the developing countries of the tropical world. The classical triad of TCP consists of abdominal pain, steatorrhoea, and diabetes. When diabetes is present, the condition is called fibrocalculous pancreatic diabetes (FCPD) which is thus a later stage of TCP. Some of the distinctive features of TCP are younger age at onset, presence of large intraductal calculi, more aggressive course of the disease, and a high susceptibility to pancreatic cancer. Pancreatic calculi are the hallmark for the diagnosis of TCP and in non-calcific cases ductal dilation on endoscopic retrograde cholangiopancreatography, computed tomography, or ultrasound helps to identify the disease. Diabetes is usually quite severe and of the insulin requiring type, but ketosis is rare. Microvascular complications of diabetes occur as frequently as in type 2 diabetes but macrovascular complications are uncommon. Pancreatic enzyme supplements are used for relief of abdominal pain and reducing the symptoms related to steatorrhoea. Early diagnosis and better control of the endocrine and exocrine dysfunction could help to ensure better survival and improve the prognosis and quality of life of TCP patients. PMID:14654569

Barman, K K; Premalatha, G; Mohan, V

2003-11-01

160

Smithsonian Tropical Research Institute  

NSDL National Science Digital Library

Most visitors to the Smithsonian Institution's museums in Washington, DC may not be aware of the activities of their Tropical Research Institute, which may have something to do with the fact that is located in Panama. The Institute's history stretches back to the early years of the 20th century, when one of its prime directives was to survey the flora and fauna of the area for the purpose of controlling diseases such as yellow fever and malaria. In 1946, the Institute came into the fold of the Smithsonian Institution, and since then it has conducted research in the areas of archaeology, behavioral ecology, environmental monitoring, and other topics. On the site, visitors can learn about the intitute's diverse research projects, international activities (such as the Center for Tropical Forest Science), and fellowship opportunities. Finally, visitors can also look at the two webcams operated by the Institute, including one that looks over the island (Barro Colorado) where they are located off the coast of Panama.

161

Experiments on seed predation by rodents and ants in the Israeli desert  

Microsoft Academic Search

Utilization of non-native seeds by seed-eating rodents and ants was studied experimentally in the field. It was found that patterns of granivory in the Israeli deserts are very similar to those reported for the same groups in the deserts of North America. Rodents are more efficient than ants at finding and harvesting seeds. Only rodents can find and harvest seeds

Zvika Abramsky

1983-01-01

162

Evidence for Higher Rates of Nucleotide Substitution in Rodents Than in Man  

Microsoft Academic Search

When the coding regions of 11 genes from rodents (mouse or rat) and man are compared with those from another mammalian species (usually bovine), it is found that rodents evolve significantly faster than man. The ratio of the number of nucleotide substitutions in the rodent lineage to that in the human lineage since their divergence is 2.0 for synonymous substitutions

Chung-I. Wu; Wen-Hsiung Li

1985-01-01

163

Haplosporangium in an Additional Rodent Host, Microtus pennsylvanicus Drummondi  

Microsoft Academic Search

SINCE 1942 1, there has been an increase in the number of reports on haplomycosis in rodents and other animals trapped in the United States, Canada and England. Two recent reports from Canada and Sweden describing further isolations of the causative organism Haplosporangium were those published by Bakerspigel2 and Jellison3.

A. Bakerspigel

1957-01-01

164

Interspecific competition in small rodents: from populations to individuals  

Microsoft Academic Search

The role of interspecific competition in shaping animal and plant communities has formed one of the major issues in ecology for decades. Small mammals, mainly rodents, have been among the model systems used for research on interspecific competition. Most studies within small mammal systems in the past have examined effects of competition on population attributes such as on population size,

Jana A. Eccard; Hannu Ylönen

2003-01-01

165

Toxoplasmosis in Rodents: Ecological Survey and First Evidences in Thailand  

E-print Network

Toxoplasmosis in Rodents: Ecological Survey and First Evidences in Thailand Sathaporn Jittapalapong, which is the causative agent of toxoplasmosis. Therefore, they serve as intermediate hosts of T. gondii individuals captured tested positive, confirming the wide range of potential mammalian hosts of toxoplasmosis

Paris-Sud XI, Université de

166

CONCENTRATED AMBIENT PARTICULATE STUDIES IN HEALTHY AND COMPROMISED RODENTS  

EPA Science Inventory

CONCENTRATED AMBIENT PARTICULATE STUDIES IN HEALTHY AND COMPROMISED RODENTS. WP Watkinson1, LB Wichers2, JP Nolan1, DW Winsett1, UP Kodavanti1, MCJ Schladweiler1, LC Walsh1, ER Lappi1, D Terrell1, R Slade1, AD Ledbetter1, and DL Costa1. 1USEPA, ORD/NHEERL/ETD/PTB, RTP, NC, US...

167

Neural representation of spatial topology in the rodent hippocampus.  

PubMed

Pyramidal cells in the rodent hippocampus often exhibit clear spatial tuning in navigation. Although it has been long suggested that pyramidal cell activity may underlie a topological code rather than a topographic code, it remains unclear whether an abstract spatial topology can be encoded in the ensemble spiking activity of hippocampal place cells. Using a statistical approach developed previously, we investigate this question and related issues in greater detail. We recorded ensembles of hippocampal neurons as rodents freely foraged in one- and two-dimensional spatial environments and used a "decode-to-uncover" strategy to examine the temporally structured patterns embedded in the ensemble spiking activity in the absence of observed spatial correlates during periods of rodent navigation or awake immobility. Specifically, the spatial environment was represented by a finite discrete state space. Trajectories across spatial locations ("states") were associated with consistent hippocampal ensemble spiking patterns, which were characterized by a state transition matrix. From this state transition matrix, we inferred a topology graph that defined the connectivity in the state space. In both one- and two-dimensional environments, the extracted behavior patterns from the rodent hippocampal population codes were compared against randomly shuffled spike data. In contrast to a topographic code, our results support the efficiency of topological coding in the presence of sparse sample size and fuzzy space mapping. This computational approach allows us to quantify the variability of ensemble spiking activity, examine hippocampal population codes during off-line states, and quantify the topological complexity of the environment. PMID:24102128

Chen, Zhe; Gomperts, Stephen N; Yamamoto, Jun; Wilson, Matthew A

2014-01-01

168

Effects of cerebral metabolic enhancers on brain function in rodents  

Microsoft Academic Search

The effects of cerebral metabolic enhancers (indeloxazine, bifemelane, idebenone, and nicergoline) on reserpine-induced hypothermia, the immobility period in forced swimming tests, and passive avoidance learning behavior were compared with the effects of amitriptyline in rodents. Indeloxazine, bifemelane, and amitriptyline antagonized hypothermia in mice given reserpine. Indeloxazine and amitriptyline decreased the immobility period in mice in the forced swimming test in

Koichiro Takahashi; Minoru Yamamoto; Masanori Suzuki; Yukiko Ozawa; Takashi Yamaguchi; Hirofumi Andoh; Kouichi Ishikawa

1995-01-01

169

A mechanism for resource allocation among sympatric heteromyid rodent species  

Microsoft Academic Search

Laboratory feeding experiments were conducted with Dipodomys ordii and Perognathus flavus in an attempt to discover a mechanism which might result in seed size selection. There was no marked difference in the proportions of four seed types collected whether the rodents foraged in the presence or absence of one another. However, analysis of the variability in weight of each of

Richard L. Hutto

1978-01-01

170

Temporal changes in a Chihuahuan Desert rodent community  

Microsoft Academic Search

We used time series analysis of ten years of monthly census data to assess the responses of both individual species and an entire community of rodents to a fluctu- ating desert environment. Autocorrelation analysis revealed different patterns of intra-annual fluctuation among the It species: Dipodomys spectabilis and Perog- nathus Jarus had pronounced annual cycles: D. ordii, D. merriaini, Chaetodipus penicillutu~,

James H. Brown; Edward J. Heske

1990-01-01

171

PERFLUOROOCTANE SULFONATE (PFOS) DISRUPTS THE THYROID STATUS IN LABORATORY RODENTS  

EPA Science Inventory

PERFLUOROOCTANE SULFONATE (PFOS) DISRUPTS THE THYROID STATUS IN LABORATORY RODENTS. C. Lau, J.R. Thibodeaux, R.G. Hanson, B.E. Gray and J.M. Rogers. Reprod. Tox. Div. NHEERL, US EPA, Research Triangle Park, NC. PFOS is an environmental contaminant ubiquitously found in h...

172

SHORT REPORT Open Access Optimizing the phenotyping of rodent ASD  

E-print Network

SHORT REPORT Open Access Optimizing the phenotyping of rodent ASD models: enrichment analysis spectrum disorders (ASD) in both forward and reverse genetic approaches. A recurrent focus has been on high-order behavioral analyses, including learning and memory paradigms and social paradigms. However, well

Paris-Sud XI, Université de

173

Andes Hantavirus Variant in Rodents, Southern Amazon Basin, Peru  

PubMed Central

We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted. PMID:24447689

Tokarz, Rafal; Ghersi, Bruno M.; Salmon-Mulanovich, Gabriela; Guezala, M. Claudia; Albujar, Christian; Mendoza, A. Patricia; Tinoco, Yeny O.; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T.; Hirschberg, David L.; Lipkin, W. Ian; Bausch, Daniel G.; Montgomery, Joel M.

2014-01-01

174

Rodents and climate: A new model for estimating past temperatures  

Microsoft Academic Search

Based on the high correlation between species richness in sigmodontine rodents and temperatures, we propose a new model in order to quantify past climates. Because of the close phylogenetic relationship and the tooth morphological similarity between extant New World cricetids (Sigmodontinae) and fossil European cricetids (Cricetinae s.l.), extant New World sigmodontines are taken as analogues for Old World fossil cricetines.

Serge Legendre; Sophie Montuire; Olivier Maridet; Gilles Escarguel

2005-01-01

175

Ultrasonic attenuation imaging in a rodent thyroid cancer model  

E-print Network

Ultrasonic attenuation imaging in a rodent thyroid cancer model Omar Zenteno¹, William Ridgway over the last decades. Although advances in ultrasonic imaging have increased the malignancy detection rate, current ultrasonic imaging markers do not provide a sufficient level of diagnostic accuracy

Illinois at Urbana-Champaign, University of

176

Phylogeography and evolutionary history of rodent-borne hantaviruses.  

PubMed

Hantavirus (Family Bunyaviridae) are mostly associated to rodents and transmitted to man by inhalation of aerosolized infected excreta of these animals. The human infection by hantaviruses can lead to severe diseases such as hemorrhagic fever with renal syndrome (HFRS) in Asia and Europe, and pulmonary syndrome (HPS) in the Americas. To determine the origin, spreading and evolutionary dynamics of rodent-borne hantaviruses, 190 sequences of nucleoprotein (N) of hantaviruses identified in 30 countries, from 1985 to 2010, were retrieved from the GenBank and analyzed using the BEAST program. Our evolutionary analysis indicates that current genetic diversity of N gene of rodent-borne hantaviruses probably was originated around 2000 years ago. Hantavirus harbored by Murinae and Arvicolinae subfamilies, probably, were originated in Asia 500-700 years ago and later spread toward Siberia, Europe, Africa and North America. Hantavirus carried by Neotominae subfamily, probably, emerged 500-600 years ago in Central America and spread toward North America. Finally, hantaviruses associated to Sigmodontinae occurred in Brazil 400 years ago and were, probably, originated from Neotominae-associated virus from northern South America. These data offer subsidies to understand the time-scale and worldwide dissemination dynamics of rodent-borne hantaviruses. PMID:24287104

Souza, W M; Bello, G; Amarilla, A A; Alfonso, H L; Aquino, V H; Figueiredo, L T M

2014-01-01

177

Assessment of the use of selected rodents in ecological monitoring  

NASA Astrophysics Data System (ADS)

Rodents can be useful in detecting environmental impacts because they are easy to study (easy to capture and handle), they can occur in densities adequate for statistical analysis, and they are ecologically important. In this study the usefulness of rodent populations for ecological monitoring was investigated by examining the effect of variation on the possibility of detecting differences among populations of rodents on 10 trapping grids. The effects of sampling frequencies and dispersal on detecting differences in population parameters among grids was also investigated, as was the possibility of inferring population parameters from correlations with habitat data. Statistically significant differences as small as 4.3 Peromyscus maniculatus/ha were detected between grids. Of 10 populations, this comprised 12% of the highest-density population and 44% of the lowest-density population. Smaller and more differences among grids were found by examining only animals surviving from previous months. Dispersal confounds detection of direct impacts to populations, especially during the breeding season. Infrequent sampling fails to detect impacts that occur between sampling periods and will indicate impacts when observed changes result from natural variation. Correlations between population parameters and habitat variables exist but should only be used in predicting, not measuring, impacts. It is concluded that some rodent populations can be used in ecological monitoring. However, intensive sampling is required to account for variation and dispersal.

Douglass, Richard J.

1989-05-01

178

Evaluation of two oral baiting systems for wild rodents.  

PubMed

Tetracycline hydrochloride (TC)-treated peanut butter or rodent chow baits were distributed during March 1990, on separate 0.53 ha sites in Oglethorpe County, Georgia (USA). Rodents were trapped on a control site prior to bait distribution and on two baited sites 6 days post-distribution. Cleaned skulls from euthanized mammals were grossly examined for TC fluorescence using an ultraviolet (UV) light. Mandibles were sectioned and examined for TC fluorescence using an ultraviolet light microscope. All 21 cotton rats (Sigmodon hispidus), four eastern harvest mice (Rithrodontomys humulis), and two golden mice (Ochrotomys nuttalli) captured on the control site were negative for TC fluorescence. On the peanut butter bait site, mandible sections from 29 of 32 (91%) cotton rats, three of three (100%) eastern harvest mice, two of three (66%) golden mice, zero of five (0%) white-footed mice (Peromyscus leucopus), one of three (33%) short-tailed shrews (Blarina brevicauda), and zero of two (0%) least shrews (Cryptotis parva) were positive for TC. Results from the rodent chow bait site indicated that 18 of 25 (72%) cotton rats, zero of three (0%) eastern harvest mice, two of seven (29%) golden mice, zero of four (0%) white-footed mice, and zero of four (0%) least shrews were positive for TC fluorescence in mandible sections. These results suggest that a large portion of a free-ranging small rodent population can be administered biological markers or vaccines using baits. PMID:9577787

Creekmore, T E; Fletcher, W O; Stallknecht, D E

1998-04-01

179

Neurobehavioral actions of coumestrol and related isoflavonoids in rodents  

Microsoft Academic Search

Isoflavonoids are plant estrogens that are increasingly advocated as a natural alternative to estrogen replacement therapy (ERT) and are available as dietary supplements. As weak estrogen agonists\\/antagonists with a range of other enzymatic activities, the isoflavonoids provide a useful model for the actions of endocrine disruptors. This paper reviews the responses of rodents to diets containing coumestrol or an isoflavone

Patricia L Whitten; Heather B Patisaul; Larry J Young

2002-01-01

180

Robust Reproducible Resting State Networks in the Awake Rodent Brain  

PubMed Central

Resting state networks (RSNs) have been studied extensively with functional MRI in humans in health and disease to reflect brain function in the un-stimulated state as well as reveal how the brain is altered with disease. Rodent models of disease have been used comprehensively to understand the biology of the disease as well as in the development of new therapies. RSN reported studies in rodents, however, are few, and most studies are performed with anesthetized rodents that might alter networks and differ from their non-anesthetized state. Acquiring RSN data in the awake rodent avoids the issues of anesthesia effects on brain function. Using high field fMRI we determined RSNs in awake rats using an independent component analysis (ICA) approach, however, ICA analysis can produce a large number of components, some with biological relevance (networks). We further have applied a novel method to determine networks that are robust and reproducible among all the components found with ICA. This analysis indicates that 7 networks are robust and reproducible in the rat and their putative role is discussed. PMID:22028788

Becerra, Lino; Pendse, Gautam; Chang, Pei-Ching; Bishop, James; Borsook, David

2011-01-01

181

Rodents as seed dispersers in a heath — oak wood succession  

Microsoft Academic Search

In a Danish heathland invasion of oak shrub has taken place, the succession rate being approximately 300 m during the last 100 years. The colonisation has occurred in steps related to the delay time between seedling stage and fertility stage. Seedlings are often found in clusters originating from caches probably made by seed-eating rodents. Apodemus sylvaticus, A. flavicollis and Clethrionomys

Thomas Secher Jensen; Ole Frost Nielsen

1986-01-01

182

EFFECTIVE VOLE CONTROL WITH ZP RODENT BAIT AG  

Microsoft Academic Search

Since the loss of DDT, Vacor (DPL 787) and other acute rodenticides and the serious use restrictions placed upon strychnine and 1080 for field use, it has become quite apparent that control of field rodents, more particular pine and meadow voles, with standard anticoagulants has become a difficult task, and in some instances impossible. Bell Laboratories, Inc. has chosen to

Edward F. Marshall

1980-01-01

183

Barnes maze testing strategies with small and large rodent models.  

PubMed

Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land (Barnes) mazes. Improved performance over sessions or trials is thought to reflect learning and memory of the escape cage/platform location. Considered less stressful than water mazes, the Barnes maze is a relatively simple design of a circular platform top with several holes equally spaced around the perimeter edge. All but one of the holes are false-bottomed or blind-ending, while one leads to an escape cage. Mildly aversive stimuli (e.g. bright overhead lights) provide motivation to locate the escape cage. Latency to locate the escape cage can be measured during the session; however, additional endpoints typically require video recording. From those video recordings, use of automated tracking software can generate a variety of endpoints that are similar to those produced in water mazes (e.g. distance traveled, velocity/speed, time spent in the correct quadrant, time spent moving/resting, and confirmation of latency). Type of search strategy (i.e. random, serial, or direct) can be categorized as well. Barnes maze construction and testing methodologies can differ for small rodents, such as mice, and large rodents, such as rats. For example, while extra-maze cues are effective for rats, smaller wild rodents may require intra-maze cues with a visual barrier around the maze. Appropriate stimuli must be identified which motivate the rodent to locate the escape cage. Both Barnes and water mazes can be time consuming as 4-7 test trials are typically required to detect improved learning and memory performance (e.g. shorter latencies or path lengths to locate the escape platform or cage) and/or differences between experimental groups. Even so, the Barnes maze is a widely employed behavioral assessment measuring spatial navigational abilities and their potential disruption by genetic, neurobehavioral manipulations, or drug/ toxicant exposure. PMID:24637673

Rosenfeld, Cheryl S; Ferguson, Sherry A

2014-01-01

184

Micro irrigation of tropical fruit crops  

Technology Transfer Automated Retrieval System (TEKTRAN)

In most tropical regions, tropical fruits are grown either in wet-and-dry climates characterized by erratic rainfall patterns and prolonged dry periods or in fertile but semiarid lands under irrigation. Little is known about water requirements of tropical crops grown in the tropics. This book chapt...

185

The Nitrogen Paradox in Tropical Forest Ecosystems  

E-print Network

cycle, tropical forests, global biogeochemistry, nitrogen fixation, nutrients, phosphorus Abstract Observations of the tropical nitrogen (N) cycle over the past half century indicate that intact tropical in the resolution of the nitrogen (N) cycle across this vast biome. Although tropical forests are quite variable

186

Copyrighted Material What Is Tropical Ecology?  

E-print Network

Copyrighted Material What Is Tropical Ecology? Asking the question, What is tropical ecology? may seem akin to asking questions such as, Who is buried in Grant's tomb? Tropical ecology is the study of the ecology of tropical regions. But so what? Consider these questions: First, what is ecology? What are its

Landweber, Laura

187

HERBIVORY AND PLANT DEFENSES IN TROPICAL FORESTS  

Microsoft Academic Search

In this review, we discuss the ecological and evolutionary consequences of plant- herbivore interactions in tropical forests. We note first that herbivory rates are higher in tropical forests than in temperate ones and that, in contrast to leaves in temperate forests, most of the damage to tropical leaves occurs when they are young and expanding. Leaves in dry tropical forests

P. D. Coley; J. A. Barone

1996-01-01

188

World Health Organization: Tropical Diseases  

NSDL National Science Digital Library

This World Health Organization website feature focuses on tropical diseases. For visitors unfamiliar with which diseases out there are considered tropical, this website provides informative fact sheets on fourteen different tropical diseases. To view the factsheets, visitors should click on "Fact Sheets on Tropical Diseases", under the General Information heading near the top of the homepage. The fact sheets cover topics such as "Symptoms", "Transmission", "Treatment", "Prevention", "Economic Cost", and "Diagnosis". Under the "Multimedia" heading near the top of the homepage, visitors can click on the link "10 Facts on Neglected Tropical Diseases", to be taken to a slide show, via the link near the bottom of the page entitled "Read More About Neglected Tropical Diseases". The slide show explains that a neglected tropical disease is a disease that costs little to prevent, does not spread to wealthy areas and is of little priority to pharmaceutical companies when it comes to research and development of medicines for them. Under the Statistics heading near the bottom of the homepage, visitors can click on a link to get to the "Global Health Database", which contains "standardized data and statistics for infectious diseases at country, regional, and global levels."

189

CHEMICAL AND RADIATION LEUKEMOGENESIS IN HUMANS AND RODENTS AND THE VALUE OF RODENT MODELS FOR ASSESSING RISKS OF LYMPHOHEMATOPOIETIC CANCERS  

EPA Science Inventory

This report is intended to provide an up-to-date overview of the lymphoid and hematopoietic diseases induced in humans and rodents following exposure to chemical agents. It includes a brief introduction to hematopoiesis and leukemia-inducing agents and their effects in mice and r...

190

Farmer's perceptions of rodents as crop pests : Knowl- edge, attitudes and practices in rodent pest management in Tanzania and Ethiopia  

Microsoft Academic Search

A study was conducted using a structured questionnaire to obtain information about the nature and extent of rodent damage to crops, farmer's perceptions of crop pests and their knowledge, attitudes and practices to their management in Tanzania and Ethiopia. The study was carried out in five localities (Makuyu -Central Tanzania; Chunya-Southwest Tanzania; Ziway and Adami Tulu (south of Addis Ababa)

Rhodes H. Makundi; Afework Bekele; Herwig Leirs; Winnie Rwamugira; Loth S. Mulungu

191

Tropical Ice Cores Measure Climate  

NSDL National Science Digital Library

This video profiles glaciologist Lonnie Thompson and his research into tropical mountain glaciers as a way to understand climate history. Beginning in the 1970s, Thompson recognized that tropical ice cores contain information relating to tropical climate phenomena, including El NiÃo events and monsoons. These phenomena are not archived in ice from polar regions. Thompson explains that his archive of ice cores is full of clues that, taken together with records collected from around the world, can help scientists create a timeline that tells Earth's climate story.

Sciencenow, Nova; Domain, Teachers'

192

Tropical Cyclone Report  

NSDL National Science Digital Library

This detailed description of Hurricane Isabel, a long-lived Cape Verde hurricane that reached Category 5 status on the Saffir-Simpson Hurricane Scale, contains a synoptic history, meteorological statistics, casualty and damage statistics, and a forecast and warning critique. The storm made landfall near Drum Inlet on the Outer Banks of North Carolina as a category 2 hurricane and is considered to be one of the most significant tropical cyclones to affect portions of northeastern North Carolina and east-central Virginia since Hurricane Hazel in 1954 and the Chesapeake-Potomac Hurricane of 1933. Voluminous charts include best track, selected ship reports, selected surface observations, and rainfall. A warnings chart is also included along with a best track map.

2007-12-12

193

Climate change ecology: Tropical languor  

NASA Astrophysics Data System (ADS)

Carbon dioxide can stimulate photosynthesis in trees and increase their growth rates. A study of tree rings from three seasonal tropical forests shows no evidence of faster growth during 150 years of increasing atmospheric CO2 concentrations.

Cernusak, Lucas A.

2015-01-01

194

Deforestation: Tropical Forests in Decline  

NSDL National Science Digital Library

The Canadian International Development Agency has placed online a draft report entitled "Deforestation: Tropical Forests in Decline." The report examines "the extent of deforestation in developing countries, its causes and consequences, and prospect of more sustainable land use alternatives."

195

Tropical Ecosystems and Ecological Concepts  

NASA Astrophysics Data System (ADS)

Over one third of the earth's terrestrial surface is situated in the tropics, with environments ranging from hot deserts to tropical rain forests. This introductory textbook, aimed at students studying tropical ecology, provides a comprehensive guide to the major tropical biomes and is unique in its balanced coverage of both aquatic and terrestrial systems. The volume considers the human ecological dimension, covering issues such as population growth, urbanization, agriculture and fisheries, natural resource use, and pollution. It is international in scope and addresses global issues such as conservation of biodiversity, climate change, and the concept of ecological sustainability. The text is supported throughout by boxes containing supplementary material on a range of topics and organisms, mathematical concepts and calculations, and is enlivened with clear line diagrams, maps, and photographs. A cross-referenced glossary, extensive bibliography, and comprehensive index are included as further aids to study.

Osborne, Patrick L.

2000-09-01

196

Tropical Cyclones and Climate Change  

E-print Network

Whether the characteristics of tropical cyclones have changed or will change in a warming climate — and if so, how — has been the subject of considerable investigation, often with conflicting results. Large amplitude ...

Knutson, Thomas R.

197

Enteric pathogens in tropical aquaria.  

PubMed Central

A total of 100 tropical aquaria from six pet shops were sampled for the presence of Salmonella, Campylobacter and Aeromonas species. Eight fish tanks contained unusual serotypes of salmonella. None had been used to house terrapins. One hundred and three isolates of Aeromonas species were obtained from 98 tanks. One tank contained Plesiomonas shigelloides. No Campylobacter species were isolated. It is suggested that a tropical aquarium may constitute an infection hazard. PMID:3428370

Sanyal, D.; Burge, S. H.; Hutchings, P. G.

1987-01-01

198

Fluid Mechanics of Tropical Cyclones  

Microsoft Academic Search

:   Typhoons in the northwest Pacific and hurricanes in the northeast Atlantic are particular instances of a global phenomenon\\u000a with frequently disastrous consequences known as the Tropical Cyclone (TC). This is an intense cyclone, generated over a tropical\\u000a ocean with kinetic energy 1018 J or more, which extends over several hundred kilometres and yet is above all characterized by its

1998-01-01

199

Challenges in tropical plant nematology.  

PubMed

A major challenge facing agricultural scientists today is the need to secure food for an increasing world population. This growth occurs predominantly in developing, mostly tropical countries, where the majority of hungry people live. Reducing yield losses caused by pathogens of tropical agricultural crops is one measure that can contribute to increased food production. Although plant-parasitic nematodes are often not as important as some other biotic and nonbiotic constraints on crop production in the tropics, they can nevertheless cause extensive damage and substantial yield losses. The effects of agricultural, environmental, socioeconomic, and policy changes on the occurrence of plant-parasitic nematodes in the tropics and the losses these pathogens cause are largely undocumented. Recent developments pose new challenges to tropical nematology. The increased application of molecular diagnostics may widen the knowledge gap between nematologists working in developed countries and in the tropics. Uncertainties concerning the validity of nematode species will lead to practical problems related to quarantine measures and nematode management. The study of interactions between nematodes and other pathogens in disease complexes provide opportunities for multidisciplinary research with scientists from other disciplines but remain underexploited. Difficulties in recognizing emerging nematode threats prevent the timely implementation of management strategies, thus increasing yield losses. Research is needed to address these challenges. Examples are presented mainly but not exclusively from banana, peanut, and rice nematology. PMID:17489690

De Waele, Dirk; Elsen, Annemie

2007-01-01

200

Tropical cyclones and climate change  

NASA Astrophysics Data System (ADS)

Whether the characteristics of tropical cyclones have changed or will change in a warming climate - and if so, how - has been the subject of considerable investigation, often with conflicting results. Large amplitude fluctuations in the frequency and intensity of tropical cyclones greatly complicate both the detection of long-term trends and their attribution to rising levels of atmospheric greenhouse gases. Trend detection is further impeded by substantial limitations in the availability and quality of global historical records of tropical cyclones. Therefore, it remains uncertain whether past changes in tropical cyclone activity have exceeded the variability expected from natural causes. However, future projections based on theory and high-resolution dynamical models consistently indicate that greenhouse warming will cause the globally averaged intensity of tropical cyclones to shift towards stronger storms, with intensity increases of 2-11% by 2100. Existing modelling studies also consistently project decreases in the globally averaged frequency of tropical cyclones, by 6-34%. Balanced against this, higher resolution modelling studies typically project substantial increases in the frequency of the most intense cyclones, and increases of the order of 20% in the precipitation rate within 100 km of the storm centre. For all cyclone parameters, projected changes for individual basins show large variations between different modelling studies.

Knutson, Thomas R.; McBride, John L.; Chan, Johnny; Emanuel, Kerry; Holland, Greg; Landsea, Chris; Held, Isaac; Kossin, James P.; Srivastava, A. K.; Sugi, Masato

2010-03-01

201

Comparison and Validation of Tropical Rainfall Measuring Mission (TRMM) Rainfall Algorithms in Tropical Cyclones.  

E-print Network

?? Tropical Rainfall Measuring Mission (TRMM) rainfall retrieval algorithms are evaluated in tropical cyclones (TCs). Differences between the Precipitation Radar (PR) and TRMM Microwave Imager… (more)

Zagrodnik, Joseph P

2012-01-01

202

Hantavirus Immunology of Rodent Reservoirs: Current Status and Future Directions  

PubMed Central

Hantaviruses are hosted by rodents, insectivores and bats. Several rodent-borne hantaviruses cause two diseases that share many features in humans, hemorrhagic fever with renal syndrome in Eurasia or hantavirus cardiopulmonary syndrome in the Americas. It is thought that the immune response plays a significant contributory role in these diseases. However, in reservoir hosts that have been closely examined, little or no pathology occurs and infection is persistent despite evidence of adaptive immune responses. Because most hantavirus reservoirs are not model organisms, it is difficult to conduct meaningful experiments that might shed light on how the viruses evade sterilizing immune responses and why immunopathology does not occur. Despite these limitations, recent advances in instrumentation and bioinformatics will have a dramatic impact on understanding reservoir host responses to hantaviruses by employing a systems biology approach to identify important pathways that mediate virus/reservoir relationships. PMID:24638205

Schountz, Tony; Prescott, Joseph

2014-01-01

203

Rodent control programmes in areas affected by Bolivian haemorrhagic fever  

PubMed Central

Bolivian haemorrhagic fever (BHF) caused by Machupo virus is acquired by contact with the excretions and secretions of Calomys callosus, an indigenous cricetine rodent which is preadapted to peridomestic habitats. It competes successfully with Mus musculus, but not with Rattus rattus. A successful disease control programme has functioned in Beni Department since 1964. It is based on trapping surveys and the detection of splenomegaly in Calomys rodents as an index of chronic virus infection. Mass trapping and poisoning are used initially, and regular trapping is employed to control Calomys populations in towns where disease has occurred. More than 1000 cases of BHF were recorded from 1960-1964, but less than 200 in the past 10 years. The cost of this programme is approximately $30 000 annually. PMID:182405

Mercado R., Rodolfo

1975-01-01

204

Experimental infections by Brucella suis type 4 in Alaskan rodents.  

PubMed

The susceptibility of nine species of rodents and one species of lagomorph to Brucella suis type 4 was studied experimentally. The rodent species included: guinea pig (Cavia porcellus), Scandinavian lemming (Lemmus lemmus), brown lemming (L. sibiricus), northern red-backed vole (Clethrionomys rutilis), varying lemmings (Dicrostonyx stevensoni and D. rubricatus), yellow-cheeked vole (Microtus xanthognathus), flying squirrel (Glaucomys sabrinus) and ground squirrel (Citellus parryii). The lagomorph, Lepus americanus (varying hare), was also studied. All of these species were readily infected by intraperitoneal inoculations of brucellae. Pathologic responses were not marked in most of these species. However, both species of varying lemmings responded dramatically to infections initiated by about as few as two cfu. All individuals of both species that were not killed eventually died from the infection. PMID:7463596

Miller, L G; Neiland, K A

1980-10-01

205

Snapshot PK: a rapid rodent in vivo preclinical screening approach.  

PubMed

Described in this article are strategies implemented to increase the throughput of in vivo rodent pharmacokinetic (PK) studies using the snapshot PK study design and automated methods for compound submission, sample processing, data analysis and reporting. Applying snapshot PK studies to categorize the oral exposure of >1300 discovery compounds as low, moderate or high resulted in an attrition rate of 86%. The follow up full PK studies on the remaining compounds found that 98% of the compounds were predicted in the correct (69%) or adjacent (29%) oral exposure category by the snapshot PK studies. These results demonstrate that the snapshot PK screen in rodents can serve as an effective and efficient in vivo tool in the compound selection process in drug discovery. PMID:18405850

Liu, Bo; Chang, Jonathan; Gordon, William P; Isbell, John; Zhou, Yingyao; Tuntland, Tove

2008-04-01

206

Hantavirus immunology of rodent reservoirs: current status and future directions.  

PubMed

Hantaviruses are hosted by rodents, insectivores and bats. Several rodent-borne hantaviruses cause two diseases that share many features in humans, hemorrhagic fever with renal syndrome in Eurasia or hantavirus cardiopulmonary syndrome in the Americas. It is thought that the immune response plays a significant contributory role in these diseases. However, in reservoir hosts that have been closely examined, little or no pathology occurs and infection is persistent despite evidence of adaptive immune responses. Because most hantavirus reservoirs are not model organisms, it is difficult to conduct meaningful experiments that might shed light on how the viruses evade sterilizing immune responses and why immunopathology does not occur. Despite these limitations, recent advances in instrumentation and bioinformatics will have a dramatic impact on understanding reservoir host responses to hantaviruses by employing a systems biology approach to identify important pathways that mediate virus/reservoir relationships. PMID:24638205

Schountz, Tony; Prescott, Joseph

2014-01-01

207

Limitations to adaptive optics image quality in rodent eyes  

PubMed Central

Adaptive optics (AO) retinal image quality of rodent eyes is inferior to that of human eyes, despite the promise of greater numerical aperture. This paradox challenges several assumptions commonly made in AO imaging, assumptions which may be invalidated by the very high power and dioptric thickness of the rodent retina. We used optical modeling to compare the performance of rat and human eyes under conditions that tested the validity of these assumptions. Results showed that AO image quality in the human eye is robust to positioning errors of the AO corrector and to differences in imaging depth and wavelength compared to the wavefront beacon. In contrast, image quality in the rat eye declines sharply with each of these manipulations, especially when imaging off-axis. However, some latitude does exist to offset these manipulations against each other to produce good image quality. PMID:22876346

Zhou, Xiaolin; Bedggood, Phillip; Metha, Andrew

2012-01-01

208

Short interspersed elements (SINEs) of the Geomyoidea superfamily rodents.  

PubMed

A new short interspersed element (SINE) was isolated from the genome of desert kangaroo rat (Dipodomys deserti) using single-primer PCR. This SINE consists of two monomers: the left monomer (IDL) resembles rodent ID element and other tRNAAla(CGC)-derived SINEs, whereas the right one (Geo) shows no similarity with known SINE sequences. PCR and hybridization analyses demonstrated that IDL-Geo SINE is restricted to the rodent superfamily Geomyoidea (families Geomyidea and Heteromyidea). Isolation and analysis of IDL-Geo from California pocket mouse (Chaetodipus californicus) and Botta's pocket gopher (Thomomys bottae) revealed some species-specific features of this SINE family. The structure and evolution of known dimeric SINEs are discussed. PMID:16517098

Gogolevsky, Konstantin P; Kramerov, Dmitri A

2006-05-24

209

Susceptibility of selected rodent species from Colorado to Borrelia burgdorferi.  

PubMed

To determine the susceptibility of some common Colorado (USA) rodent species to Borrelia burgdorferi, pregnant Peromyscus maniculatus, Tamias minimus, and Spermophilus lateralis were trapped in May 1990 and kept in quarantine until their young were old enough to be used in the experiment. Six to eight 8-wk-old individuals of each of the Colorado species and, for comparison, eight laboratory raised P. leucopus were subcutaneously inoculated with > or = 10(5) spirochetes in 0.1 ml in July 1990. Tissue specimens were collected for isolation from these animals through April 1991. Spirochetes were isolated from blood, ear, bladder, kidney, spleen, liver, and eye in Barbour-Stoener-Kelly (BSK) medium from P. maniculatus, P. leucopus and T. minimus. Spirochetes were isolated from at least one tissue from all of these animals and no isolations were obtained from any of the S. lateralis. Thus, three of the four rodent species tested are susceptible to, and could harbor, B. burgdorferi. PMID:8722268

Ubico, S R; McLean, R G; Cooksey, L M

1996-04-01

210

Tropical Cyclone Gonu  

NASA Technical Reports Server (NTRS)

You might expect to see a storm with near-perfect symmetry and a well-defined eye hovering over the warm waters of the Caribbean or in the South Pacific, but Tropical Cyclone Gonu showed up in an unusual place. On June 4, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this image, Tropical Cyclone Gonu was approaching the northeastern shore of Oman, a region better known for hot desert conditions. Though rare, cyclones like Gonu are not unheard of in the northern Indian Ocean basin. Most cyclones that form in the region form over the Bay of Bengal, east of India. Those that take shape over the Arabian Sea, west of the Indian peninsula, tend to be small and fizzle out before coming ashore. Cyclone Gonu is a rare exception. As of June 4, 2007, the powerful storm had reached a dangerous Category Four status, and it was forecast to graze Oman's northeastern shore, following the Gulf of Oman. According to storm statistics maintained on Unisys Weather, the last storm of this size to form over the Arabian Sea was Cyclone 01A, which tracked northwest along the coast of India between May 21 and May 28, 2001. Unlike Gonu's forecasted track, Cyclone 01A never came ashore. MODIS acquired this photo-like image at 12:00 p.m. local time (9:00 UTC), a few hours after the Joint Typhoon Warning Center estimated Gonu's sustained winds to be over 240 kilometers per hour (145 miles per hour). The satellite image confirms that Gonu was a super-powerful cyclone. The storm has the hallmark tightly wound arms that spiral around a well-defined, circular eye. The eye is surrounded by a clear wall of towering clouds that cast shadows on the surrounding clouds. Called hot towers, these clouds are a sign of the powerful uplift that feeds the storm. The symmetrical spirals, clear eye, and towering clouds are all features regularly seen in satellite images of other particularly powerful cyclones, which are also known as typhoons or hurricanes when they form in other parts of the world. The high-resolution image provided above is at MODIS' full spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response System provides this image at additional resolutions.

2007-01-01

211

Defensive burying in rodents: ethology, neurobiology and psychopharmacology  

Microsoft Academic Search

Defensive burying refers to the typical rodent behavior of displacing bedding material with vigorous treading-like movements of their forepaws and shoveling movements of their heads directed towards a variety of noxious stimuli that pose a near and immediate threat, such as a wall-mounted electrified shock-prod. Since its introduction 25 years ago by Pinel and Treit [J. Comp. Physiol. Psychol. 92

Sietse F. De Boer; Jaap M. Koolhaas

2003-01-01

212

Mating strategies of a nocturnal, desert rodent ( Dipodomys spectabilis )  

Microsoft Academic Search

Summary The mating system of a nocturnal, desert rodent, the banner-tailed kangaroo rat (Dipodomys spectabilis) was studied through direct observation, live-trapping, and radiotelemetry over a 13-month period from August 1986 to August 1987. Mating behavior varied from exclusive matings between male and female neighbors to competitive mate searching and direct male competition. In summer matings and early in a November

Jan A. Randall

1991-01-01

213

Echocardiographic characterization of the cardiovascular phenotype in rodent models.  

PubMed

Echocardiographic techniques are commonly utilized to describe the rodent cardiovascular phenotype. These approaches are contrasted with other in vivo methods and are positioned in the assay selection process by a review of studies from our laboratory and others. Although not conventionally considered a biomarker, the technique has the potential to be exploited as a marker of intentional or unanticipated toxic biological effects in the preclinical development of drugs and chemicals. PMID:16507551

Hoit, Brian D

2006-01-01

214

Early Miocene rodents and insectivores from northeastern Colorado  

E-print Network

THE UNIVERSITY OF KANSAS PALEONTOLOGICAL CONTRIBUTIONS VE RTE B RATA ARTICLE 7 Pages 1-92, Figures 1-131 EARLY MIOCENE RODENTS AND INSECTIVORES FROM NORTHEASTERN COLORADO By ROBERT W. WILSON ARTICLE 8 Pages 1-24, Figures 1-21 A NEW ARMORED DINOSAUR... AND INSECTIVORES FROM NORTHEASTERN COLORADO By ROBERT W. WILSON (Contribution from the Museum of Natural History) THE UNIVERSITY OF KANSAS PUBLICATIONS November 21, 1960 PRINTED BY THE UNIVERSITY OF KANSAS PRESS LAWRENCE THE UNIVERSITY OF KANSAS PALEONTOLOGICAL...

Wilson, R. W.

1960-11-21

215

USING SURVIVAL OF RODENTS TO ASSESS QUALITY OF PRAIRIE HABITATS  

Microsoft Academic Search

ABSTRACT—Estimates of abundance,commonly,are used,for assessing quality of wildlife habitat. However, disparities between abundance and fitness parameters make the utility of abundance for predicting quality of habitat questionable. We used survival of rodents and rates of capture to assess quality of habitat in greasewood,scrub and sandhill prairie habitats at the United States Army Pueblo Chemical Depot, Pueblo, Colorado. Only the Ord’s

Robert A. Schorr; Jeremy L. Siemers; Paul M. Lukacs; James P. Gionfriddo; John R. Sovell; Renee J. Rondeau; Michael B. Wunder

2007-01-01

216

In vivo microCT imaging of rodent cerebral vasculature  

Microsoft Academic Search

Computed tomography (CT) remains a critical diagnostic tool for evaluating patients with cerebrovascular disease, and the advent of specialized systems for imaging rodents has extended these techniques to small animal models of these diseases. We therefore have evaluated in vivo methods of imaging rat models of hemorrhagic stroke using a high resolution compact computed tomography (‘microCT’) system (FLEX(tm) X-O(tm), Gamma

Youngho Seo; Tomoki Hashimoto; Yoshitsugu Nuki; Bruce H Hasegawa

2008-01-01

217

Induction of Covalent DNA Adducts in Rodents by Tamoxifen  

Microsoft Academic Search

The antiestrogen tamoxifen, increasingly used as adjuvant treatment for breast cancer, has been found to covalently modify DNA of rodents. For instance, the liver DNA of female Sprague-Dawley rats treated with a single injection of tamoxifen contained two DNA adducts. Four addi tional DNA adducts were formed and adduct concentrations increased 5- 7- and 10-15-fold after three and six tamoxifen

Xueliang Han

218

Rodent seed predation and seedling recruitment in mesic grassland  

Microsoft Academic Search

Seedling recruitment of two grasses (Arrhenatherum elatius and Festuca rubra) and two herbs (Centaurea nigra and Rumex acetosa) was measured in areas with and without rodents to which seeds of each species were sown at three seed densities (1000, 10,000\\u000a and 50,000 seeds m?2) in two seasons (spring and autumn 1995). Seed removal was measured for 10-day periods and the

G. R. Edwards; M. J. Crawley

1999-01-01

219

Ventilatory accommodation of changing oxygen demand in sciurid rodents  

Microsoft Academic Search

Ventilation was measured across a range of O2 consumption rates in four sciurid rodents: Tamias minimus (47 g), Spermophilus lateralis (189 g), S. beecheyi (531 g), and Marmota flaviventris juveniles (1054 g) and adults (2989 g). Maximum thermogenic oxygen consumption was measured for all but adult M. flaviventris. Aerobic scopes (maximum\\/minimum O2 consumption rates) were 4.6, 3.8, 5.4, and 4.8

Mark A. Chappell

1992-01-01

220

Beyond the rodent model: Calorie restriction in rhesus monkeys  

Microsoft Academic Search

Lifespan extension and reduction of age-related disease by calorie restriction (CR) are among the most consistent findings\\u000a in gerontological research. The well known effects of CR have been demonstrated many times in rodents and other short-lived\\u000a species. However, effects of CR on aging in longer-lived species, more closely related to humans, were unknown until recently.\\u000a Studies of CR and aging

Donald K. Ingram; George S. Roth

1997-01-01

221

Evaluation of Two Oral Baiting Systems for Wild Rodents  

Microsoft Academic Search

of32 (91%) cotton rats, three ofthree (100%) eastern harvest mice, two of three (66%) gold- en mice, zero of five (0%) white-footed mice (Peroniyscus leucopus), one of three (33%) short-tailed shrews (Blarina brevicauda), and zero of two (0%) least shrews (Cnjptotis parva) were positive for TC. Results from the rodent chow bait site indicated that 18 of 25 (72%) cotton

Terry E. Creekmore; David E. Stallknecht

1995-01-01

222

PHYLOGENETICS OF THE NEW WORLD RODENT FAMILY HETEROMYIDAE  

Microsoft Academic Search

The family Heteromyidae includes 6 genera of rodents traditionally placed in 3 subfamilies endemic to the Nearctic and northern Neotropical biogeographic regions. Although several of these taxa represent intensively studied members of North and Central American ecosystems (e.g., kangaroo rats and pocket mice), phylogenetic relationships within and among subfamilies, genera, and species-groups are not well understood. Here, we used maximum-likelihood,

Lois F. Alexander; Brett R. Riddle

2005-01-01

223

Evidence for rodent-common and species-typical limb and digit use in eating, derived from a comparative analysis of ten rodent species  

Microsoft Academic Search

Order Rodentia comprises a vast portion of mammalian species (1814 species), which occupy extremely diverse habitats requiring very distinct motor specializations (e.g. burrowing, hopping, climbing, flying and swimming). Although early classification of paw use ability suggests rodents are impoverished relative to primates and make little use of their paws, there have been no systematic investigations of paw use in rodents.

I. Q. Whishaw; J. R. Sarna; S. M. Pellis

1998-01-01

224

Rodent damage to natural and replanted mountain forest regeneration.  

PubMed

Impact of small rodents on mountain forest regeneration was studied in National Nature Reserve in the Beskydy Mountains (Czech Republic). A considerable amount of bark damage was found on young trees (20%) in spring after the peak abundance of field voles (Microtus agrestis) in combination with long winter with heavy snowfall. In contrast, little damage to young trees was noted under high densities of bank voles (Myodes glareolus) with a lower snow cover the following winter. The bark of deciduous trees was more attractive to voles (22% damaged) than conifers (8%). Young trees growing in open and grassy localities suffered more damage from voles than those under canopy of forest stands (?² = 44.04, P < 0.001). Natural regeneration in Nature Reserve was less damaged compared to planted trees (?² = 55.89, P < 0.001). The main factors influencing the impact of rodent species on tree regeneration were open, grassy habitat conditions, higher abundance of vole species, tree species preferences- and snow-cover condition. Under these conditions, the impact of rodents on forest regeneration can be predicted. Foresters should prefer natural regeneration to the artificial plantings. PMID:22666163

Heroldová, Marta; Bryja, Josef; Jánová, Eva; Suchomel, Josef; Homolka, Miloslav

2012-01-01

225

Molecular detection of Bartonella species infecting rodents in Slovenia.  

PubMed

Rodents, collected in three zoogeographical regions across Slovenia, were tested for the presence of bartonellae using direct PCR-based amplification of 16S/23S rRNA gene intergenic spacer region (ITS) fragments from splenic DNA extracts. Bartonella DNA was detected in four species of rodents, Apodemus flavicollis, Apodemus sylvaticus, Apodemus agrarius and Clethrionomys glareolus, in all three zoogeographic regions at an overall prevalence of 40.4%. The prevalence of infection varied significantly between rodent species and zoogeographical regions. Comparison of ITS sequences obtained from bartonellae revealed six sequence variants. Four of these matched the ITS sequences of the previously recognized species, Bartonella taylorii, Bartonella grahamii, Bartonella doshiae and Bartonella birtlesii, but one was new. The identity of the bartonellae from which the novel ITS sequences was obtained were further assessed by sequence analysis of cell division protein-encoding gene (ftsZ) fragments. This analysis demonstrated that the strain is most likely a representative of possible new species within the genus. PMID:17374132

Knap, Natasa; Duh, Darja; Birtles, Richard; Trilar, Tomi; Petrovec, Miroslav; Avsic-Zupanc, Tatjana

2007-06-01

226

Principles of rodent surgery for the new surgeon.  

PubMed

For both scientific and animal welfare reasons, training in basic surgical concepts and techniques should be undertaken before ever seeking to perform surgery on a rodent. Students, post-doctoral scholars, and others interested in performing surgery on rodents as part of a research protocol may not have had formal surgical training as part of their required coursework. Surgery itself is a technical skill, and one that will improve with practice. The principles of aseptic technique, however, often remain unexplained or untaught. For most new surgeons, this vital information is presented in piecemeal fashion or learned on the job, neither of which is ideal. It may also make learning how to perform a particular surgery difficult, as the new surgeon is learning both a surgical technique and the principles of asepsis at the same time. This article summarizes and makes recommendations for basic surgical skills and techniques necessary for successful rodent surgery. This article is designed to supplement hands-on training by the user's institution. PMID:21248700

Pritchett-Corning, Kathleen R; Luo, Yiying; Mulder, Guy B; White, William J

2011-01-01

227

Propylene oxide: genotoxicity profile of a rodent nasal carcinogen.  

PubMed

Propylene oxide (PO) is a DNA-reactive genotoxic agent; that is, it reacts with DNA to produce lesions in the genetic material. PO also induces tumors in rodents, although only at high concentrations and at portals of entry. This review of PO's genotoxicity profile is organized according to endpoints measured, that is, nonmutational or mutational endpoints, and as to whether the results were from in vitro or in vivo studies. In addition to results of experimental studies, PO's genotoxicity for humans is assessed by reviewing results of published biomarker studies. The weight of evidence indicates that although it is genotoxic, PO's potency as a DNA-reactive mutagen is weak. Other aspects of PO's overall tissue toxicities are also reviewed, with attention to glutathione (GSH) depletion and its consequences, that is, cell proliferation, death, and necrosis. These toxic tissue responses occur in the same anatomical regions in rodents as do the PO-induced tumors. Furthermore, some of these tissue toxicities can produce effects that may either augment PO's DNA-reactive mutagenicity or be genotoxic in themselves, not dependent on PO's DNA reactivity. Although its DNA reactivity may be a necessary component of PO's overall genotoxicity and rodent carcinogenicity, it is likely not sufficient, and the associated tissue toxicities, which are rate-limiting, also seem to be required. This complex mode of action has implications for estimations of PO's cancer potential in humans, especially at low exposure concentrations. PMID:17661214

Albertini, Richard J; Sweeney, Lisa M

2007-01-01

228

Rodent Models of Depression: Neurotrophic and Neuroinflammatory Biomarkers  

PubMed Central

Rodent models are an indispensable tool for studying etiology and progress of depression. Since interrelated systems of neurotrophic factors and cytokines comprise major regulatory mechanisms controlling normal brain plasticity, impairments of these systems form the basis for development of cerebral pathologies, including mental diseases. The present review focuses on the numerous experimental rodent models of depression induced by different stress factors (exteroceptive and interoceptive) during early life (including prenatal period) or adulthood, giving emphasis to the data on the changes of neurotrophic factors and neuroinflammatory indices in the brain. These parameters are closely related to behavioral depression-like symptoms and impairments of neuronal plasticity and are both gender- and genotype-dependent. Stress-related changes in expression of neurotrophins and cytokines in rodent brain are region-specific. Some contradictory data reported by different groups may be a consequence of differences of stress paradigms or their realization in different laboratories. Like all experimental models, stress-induced depression-like conditions are experimental simplification of clinical depression states; however, they are suitable for understanding the involvement of neurotrophic factors and cytokines in the pathogenesis of the disease—a goal unachievable in the clinical reality. These major regulatory systems may be important targets for therapeutic measures as well as for development of drugs for treatment of depression states. PMID:24999483

Stepanichev, Mikhail; Dygalo, Nikolay N.; Grigoryan, Grigory; Shishkina, Galina T.; Gulyaeva, Natalia

2014-01-01

229

Rodent Damage to Natural and Replanted Mountain Forest Regeneration  

PubMed Central

Impact of small rodents on mountain forest regeneration was studied in National Nature Reserve in the Beskydy Mountains (Czech Republic). A considerable amount of bark damage was found on young trees (20%) in spring after the peak abundance of field voles (Microtus agrestis) in combination with long winter with heavy snowfall. In contrast, little damage to young trees was noted under high densities of bank voles (Myodes glareolus) with a lower snow cover the following winter. The bark of deciduous trees was more attractive to voles (22% damaged) than conifers (8%). Young trees growing in open and grassy localities suffered more damage from voles than those under canopy of forest stands (?2 = 44.04, P < 0.001). Natural regeneration in Nature Reserve was less damaged compared to planted trees (?2 = 55.89, P < 0.001). The main factors influencing the impact of rodent species on tree regeneration were open, grassy habitat conditions, higher abundance of vole species, tree species preferences- and snow-cover condition. Under these conditions, the impact of rodents on forest regeneration can be predicted. Foresters should prefer natural regeneration to the artificial plantings. PMID:22666163

Heroldová, Marta; Bryja, Josef; Jánová, Eva; Suchomel, Josef; Homolka, Miloslav

2012-01-01

230

Sexual Selection Halts the Relaxation of Protamine 2 among Rodents  

PubMed Central

Sexual selection has been proposed as the driving force promoting the rapid evolutionary changes observed in some reproductive genes including protamines. We test this hypothesis in a group of rodents which show marked differences in the intensity of sexual selection. Levels of sperm competition were not associated with the evolutionary rates of protamine 1 but, contrary to expectations, were negatively related to the evolutionary rate of cleaved- and mature-protamine 2. Since both domains were found to be under relaxation, our findings reveal an unforeseen role of sexual selection: to halt the degree of degeneration that proteins within families may experience due to functional redundancy. The degree of relaxation of protamine 2 in this group of rodents is such that in some species it has become dysfunctional and it is not expressed in mature spermatozoa. In contrast, protamine 1 is functionally conserved but shows directed positive selection on specific sites which are functionally relevant such as DNA-anchoring domains and phosphorylation sites. We conclude that in rodents protamine 2 is under relaxation and that sexual selection removes deleterious mutations among species with high levels of sperm competition to maintain the protein functional and the spermatozoa competitive. PMID:22216223

Lüke, Lena; Vicens, Alberto; Serra, Francois; Luque-Larena, Juan Jose; Dopazo, Hernán; Roldan, Eduardo R. S.; Gomendio, Montserrat

2011-01-01

231

Feedback-related negativity observed in rodent anterior cingulate cortex.  

PubMed

The feedback-related negativity (FRN) refers to a difference in the human event-related potential (ERP) elicited by feedback indicating success versus failure: the difference appears negative when subtracting the success ERP from the failure ERP (Miltner et al., 1997). Although source localization techniques (e.g., BESA) suggest that the FRN is produced in the ACC, the inverse problem (that any given scalp distribution can be produced by an infinite number of possible dipole configurations) limits the certainty of this conclusion. The inverse problem can be circumvented by directly recording from the ACC in animal models. Although a non-human primate homologue of the FRN has been observed in the macaque monkey (e.g. Emeric et al., 2008), a homologue of the FRN has yet to be identified in rodents. We recorded local field potentials (LFPs) directly from the ACC in 6 rodents in a task based on the FRN paradigm. The animals were trained to poke their nose into a lighted port and received a feedback smell indicating whether or not a reward pellet would drop 1.5s later. We observed a FRN-like effect time-locked to the feedback scent whereby the LFP to feedback predicting no-reward was significantly more negative than the LFP to feedback predicting reward. This deflection began on average 130ms before behavioral changes in response to the feedback. Thus, we provide the first evidence of the existence of a rodent homologue of the FRN. PMID:25237010

Warren, Christopher M; Hyman, James M; Seamans, Jeremy K; Holroyd, Clay B

2014-09-16

232

Rodent Models and Imaging Techniques to Study Liver Regeneration.  

PubMed

The liver has the unique capability of regeneration from various injuries. Different animal models and in vitro methods are used for studying the processes and mechanisms of liver regeneration. Animal models were established either by administration of hepatotoxic chemicals or by surgical approach. The administration of hepatotoxic chemicals results in the death of liver cells and in subsequent hepatic regeneration and tissue repair. Surgery includes partial hepatectomy and portal vein occlusion or diversion: hepatectomy leads to compensatory regeneration of the remnant liver lobe, whereas portal vein occlusion leads to atrophy of the ipsilateral lobe and to compensatory regeneration of the contralateral lobe. Adaptation of modern radiological imaging technologies to the small size of rodents made the visualization of rodent intrahepatic vascular anatomy possible. Advanced knowledge of the detailed intrahepatic 3D anatomy enabled the establishment of refined surgical techniques. The same technology allows the visualization of hepatic vascular regeneration. The development of modern histological image analysis tools improved the quantitative assessment of hepatic regeneration. Novel image analysis tools enable us to quantify reliably and reproducibly the proliferative rate of hepatocytes using whole-slide scans, thus reducing the sampling error. In this review, the refined rodent models and the newly developed imaging technology to study liver regeneration are summarized. This summary helps to integrate the current knowledge of liver regeneration and promises an enormous increase in hepatological knowledge in the near future. © 2014 S. Karger AG, Basel. PMID:25402256

Wei, Weiwei; Dirsch, Olaf; Lawson Mclean, Anna; Zafarnia, Sara; Schwier, Michael; Dahmen, Uta

2014-11-12

233

Karyotype and reproduction mode of the rodent parasite Strongyloides venezuelensis.  

PubMed

SUMMARY Strongyloides venezuelensis is a parasitic nematode that infects rodents. Although Strongyloides species described to date are known to exhibit parthenogenetic reproduction in the parasitic stage of their life cycle and sexual reproduction in the free-living stage, we did not observe any free-living males in S. venezuelensis in our strain, suggesting that the nematode is likely to depend on parthenogenetic reproduction. We confirmed by cytological analysis that S. venezuelensis produces eggs by parthenogenesis during the parasitic stage of its life cycle. Phylogenetic analysis using nearly the full length of 18S and D3 region of 28S ribosomal RNA gene suggested that S. venezuelensis is distantly related to another rodent parasite, namely Strongyloides ratti, but more closely related to a ruminant parasite, Strongyloides papillosus. Karyotype analysis revealed S. venezuelensis reproduces with mitotic parthenogenesis, and has the same number of chromosomes as S. papillosus (2n = 4), but differs from S. ratti (2n = 6) in this regard. These results, taken together, suggest that S. venezuelensis evolved its parasitism for rodents independently from S. ratti and, therefore, is likely to have a different reproductive strategy. PMID:25089654

Hino, Akina; Tanaka, Teruhisa; Takaishi, Maho; Fujii, Yumiko; Palomares-Rius, Juan E; Hasegawa, Koichi; Maruyama, Haruhiko; Kikuchi, Taisei

2014-11-01

234

Recognition and management of rodent-borne infectious disease outbreaks after heavy rainfall and flooding.  

PubMed

Climatic events, especially heavy rains and flooding following periods of relative drought, have precipitated both arthropod-borne and rodent-borne infectious disease outbreaks. Heavy rainfall encourages excessive wild grass seed production that supports increased outdoor rodent populations, and flooding forces rodents from their burrows near water sources into the built environment and closer to humans. The objectives of this review are to alert clinicians to the climatic conditions common to hurricane-prone regions, such as Louisiana, that can precipitate outbreaks of the two rodent-borne diseases most often associated with periods of heavy rainfall and flooding, leptospirosis (LS) and hantavirus pulmonary syndrome (HPS). It will also describe the epidemiology, presenting clinical manifestations and outcomes of these rodent-borne infectious diseases, and recommend both prophylactic therapies and effective control and prevention strategies for rodent-borne infectious disease outbreaks. Healthcare providers should maintain high levels of suspicion for LS in patients developing febrile illnesses after contaminated freshwater exposures during flooding or recreational events, and for HPS in patients with febrile illnesses that progress rapidly to respiratory failure following rodent exposures in enclosed spaces. Public health educational strategies should encourage limiting human contact with all wild and peridomestic rats and mice, avoiding all contact with rodent excreta, safely disposing of all rodent excreta, and modifying the built environment to deter rodents from colonizing households and workplaces. PMID:25369218

Diaz, James H

2014-01-01

235

Transitions between Andean and Amazonian centers of endemism in the radiation of some arboreal rodents  

PubMed Central

Background The tropical Andes and Amazon are among the richest regions of endemism for mammals, and each has given rise to extensive in situ radiations. Various animal lineages have radiated ex situ after colonizing one of these regions from the other: Amazonian clades of dendrobatid frogs and passerine birds may have Andean ancestry, and transitions from the Amazon to Andes may be even more common. To examine biogeographic transitions between these regions, we investigated the evolutionary history of three clades of rodents in the family Echimyidae: bamboo rats (Dactylomys-Olallamys-Kannabateomys), spiny tree-rats (Mesomys-Lonchothrix), and brush-tailed rats (Isothrix). Each clade is distributed in both the Andes and Amazonia, and is more diverse in the lowlands. We used two mitochondrial (cyt-b and 12S) and three nuclear (GHR, vWF, and RAG1) markers to reconstruct their phylogenetic relationships. Tree topologies and ancestral geographic ranges were then used to determine whether Andean forms were basal to or derived from lowland radiations. Results Four biogeographic transitions are identified among the generic radiations. The bamboo rat clade unambiguously originated in the Amazon ca. 9 Ma, followed by either one early transition to the Andes (Olallamys) and a later move to the Amazon (Dactylomys), or two later shifts to the Andes (one in each genus). The Andean species of both Dactylomys and Isothrix are sister to their lowland species, raising the possibility that highland forms colonized the Amazon Basin. However, uncertainty in their reconstructed ancestral ranges obscures the origin of these transitions. The lone Andean species of Mesomys is confidently nested within the lowland radiation, thereby indicating an Amazon-to-Andes transition ca. 2 Ma. Conclusions Differences in the timing of these biogeographic transitions do not appear to explain the different polarities of these trees. Instead, even within the radiation of a single family, both Andean and Amazonian centers of endemism appear enriched by lineages that originated in the other region. Our survey of other South American lineages suggests a pattern of reciprocal exchange between these regions—among mammals, birds, amphibians, and insects we found no fewer than 87 transitions between the Andes and Amazon from Miocene-Pleistocene. Because no clear trend emerges between the timing and polarity of transitions, or in their relative frequency, we suggest that reciprocal exchange between tropical highland and lowland faunas in South America has been a continual process since ca. 12 Ma. PMID:24015814

2013-01-01

236

Tropical Cyclogenesis in a Tropical Wave Critical Layer: Easterly Waves  

NASA Technical Reports Server (NTRS)

The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside.

Dunkerton, T. J.; Montgomery, M. T.; Wang, Z.

2009-01-01

237

Past glaciation in the tropics  

NASA Astrophysics Data System (ADS)

Tropical glaciers are considered along three meridional profiles, for the Australasian sector, Africa and the Americas. Evaluated are the annual mean freezing level 0 °C, modern equilibrium line altitude MEL, and past equilibrium line altitude PEL. The calculation of 0 °C is based on a 1958-1997 global data set; MEL refers to estimates concerning the first half of the 20th century; and the timing of the PEL is not generally known. 0 °C stands around 4000-5000 m, with lower levels in the outer tropics. MEL is reached in the Australasian sector on four mountains, and in Africa on three mountains, near the Equator, near or above 0 °C. In the American cordilleras many peaks are still glaciated, above 0 °C, but in the arid southern tropical Andes even summits above 6000 m do not reach MEL. The PEL stands between 3000 m and 5000 m, high in the equatorial zone, but highest in the arid southern tropical Andes. The height difference between MEL and PEL is of order 1000 m, with regional differences. Deglaciation dates range between 15,000 and 8000 years BP, with later timing towards the higher elevations. This synopsis suggests priority targets for further research: morphological mapping and age determination in the High Atlas of Morocco; timing of deglaciation in the High Semyen of Ethiopia and the Altos de Cuchumatanes of Guatemala; exploration in the highlands of Lesotho and of the Dominican Republic; and glaciation in the arid southern tropical Andes.

Hastenrath, Stefan

2009-05-01

238

Maize, tropical (Zea mays L.).  

PubMed

Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines. PMID:25300835

Assem, Shireen K

2015-01-01

239

High Altitude Glaciers in the Tropics  

NSDL National Science Digital Library

While it may seem like a contradiction, glaciers do exist in the tropical latitudes. In this video produced by ThinkTV, learn about tropical glaciers and why scientists are studying them to better understand global climate change.

Thinktv

2010-11-30

240

Midlevel Ventilation's Constraint on Tropical Cyclone Intensity  

E-print Network

Midlevel ventilation, or the flux of low-entropy air into the inner core of a tropical cyclone (TC), is a hypothesized mechanism by which environmental vertical wind shear can constrain a tropical cyclone’s intensity. An ...

Tang, Brian Hong-An

241

A Ventilation Index for Tropical Cyclones  

E-print Network

An important environmental control of both tropical cyclone intensity and genesis is vertical wind shear. One hypothesized pathway by which vertical shear affects tropical cyclones is midlevel ventilation—or the flux of ...

Tang, Brian

242

Estimating tropical cyclone precipitation risk in Texas  

E-print Network

This paper uses a new rainfall algorithm to simulate the long-term tropical cyclone precipitation (TCP) climatology in Texas based on synthetic tropical cyclones generated from National Center for Atmospheric Research/National ...

Zhu, Laiyin

243

ULTRADISCRETE CONNECTION MATRICES OVER A TROPICAL SEMIRING  

E-print Network

ULTRADISCRETE CONNECTION MATRICES OVER A TROPICAL SEMIRING- plus semiring. We extend theorems of Birkhoff et. al. to the realm of th* *is tropical semiring by showing that under certain conditions one may defin* *e a connection matrix analogous

Sydney, University of

244

Hindawi Publishing Corporation Journal of Tropical Medicine  

E-print Network

Hindawi Publishing Corporation Journal of Tropical Medicine Volume 2012, Article ID 123843, 8 pages, the exact mode of transmission of M. ulcerans remains unclear. #12;2 Journal of Tropical Medicine Buruli

Paris-Sud XI, Université de

245

The multiple vortex nature of tropical cyclogenesis  

E-print Network

This thesis contains an observational analysis of the genesis of Tropical Storm Allison (2001). Using a paradigm of tropical cyclone formation as the superposition of potential vorticity (PV) anomalies, the importance of different scales of PV...

Sippel, Jason Allen

2005-02-17

246

Structure in a desert rodent community: use of space around Dipodomys spectabilis mounds  

Microsoft Academic Search

In an earlier paper (Bowers et al. 1987) we reported patterns of microhabitat use by desert rodents among 0.25-ha plots where seeds were added or certain rodent species removed. We used the results to make inferences about the spatial organization of the whole rodent community. Here we change our focus to test for spatial usage patterns at a smaller (within-plot)

M. A. Bowers; J. H. Brown

1992-01-01

247

The African lily Massonia depressa (Hyacinthaceae) the First Monocotyledon Discovered to be Pollinated by Rodents  

NSDL National Science Digital Library

A nocturnal rodent, Gerbilluris paeba, feeds on the copious amounts of jelly-like nectar produced by flowers of the African lily Massonia depressa (Hyacinthaceae). This lily, which has flowers situated at ground level, is the first monocotyledon discovered to be pollinated by rodents. The striking similarities between the flowers of M. depressa and those of unrelated rodent-pollinated Protea spp. (Proteaceae) provide strong support for the concept of convergent floral syndromes.

Anton Pauw (University of Cape Town, Department of Botany ADR;POSTAL); Steve Johnson (University of Natal;School of Botany and Zoology ADR;POSTAL)

2004-03-09

248

International Center for Tropical Agriculture  

NSDL National Science Digital Library

From cassavas to papayas, the International Center for Tropical Agriculture is concerned with the viability of crops across the world. Specifically, their stated mission is "to reduce hunger and poverty in the tropics through collaborative research that improves agricultural productivity and natural resource management." From their homepage, visitors can read press releases and statements about their most recent findings, and also look over timely documents such as "Integrated Soil Fertility Management in the Tropics" as well as their annual report. The "Research" section is another good place to wander around, as it contains reports on two of their primary areas of interest: agrobiodiversity and the interaction between people and agroecosystems. Finally, it is worth noting that many of the materials here are also available in Spanish.

249

Multiple Co-infections of Rodents with Hantaviruses, Leptospira, and Babesia in Croatia  

PubMed Central

Abstract Hantaviruses, Leptospira spp., and Babesia spp. are rodent-borne pathogens present worldwide. We studied multiple co-infections of small rodents in Croatia with all three pathogens. Twenty-eight Apodemus flavicollis and 16 Myodes glareolus were tested for the presence of hantavirus RNA by real-time RT-PCR, Leptospira strains by renoculture method and Babesia DNA by PCR. Anti-hantavirus antibodies and anti-Leptospira antibodies were detected by serological methods. Very high infection rates with each pathogen were found in A. flavicollis: 20 of 28 rodents (71%) were infected with Dobrava virus, 13 rodents (46%) were infected with Leptospira, and 5 rodents (18%) were infected with Babesia. Multiple co-infections with all three pathogens were found in 3 of 28 (11%) A. flavicollis animals, suggesting that the same rodent host can be infected with several pathogens at the same time. Dual infections with both hantaviruses and Leptospira were found in 7 of 44 rodents (16%), with hantaviruses and Babesia in 2 rodents (5%), and double infection with both Leptospira and Babesia were found in 1 rodent (2%). Since hantaviruses, Leptospira, and Babesia have similar geographical distributions, it is to be expected that in other parts of the world multiple co-infections, representing a serious threat to public health, can be found. PMID:22217170

Turk, Nenad; Korva, Miša; Margaleti?, Josip; Beck, Relja; Vucelja, Marko; Habuš, Josipa; Svoboda, Petra; Županc, Tatjana Avši?; Henttonen, Heikki; Markoti?, Alemka

2012-01-01

250

Studies on the immunobiology of infections with the metacestodes of Echinococcus multilocularis in rodents.  

E-print Network

??The relationships among parasite growth, responses to infection and host genetic factors were examined in rodents infected with Echinococcus multilocularis. Mongolian gerbils, cotton rats and… (more)

Kroeze, Wesley Kars

1987-01-01

251

Glacial climate in the tropics  

SciTech Connect

New findings have caused ideas about the Earth`s climate during the Pleistocene glaciation to change. A consensus seems to be forming that during times of glaciation, climatic conditions in the tropics were quite different from those today. However still to be explained is why strontium-calcium measurements on corals and moble gas measurements of ground water suggest a tropical cooling of 4-6 C while foraminiferal speciation, oxygen isotope, and alkenone results suggest a cooling of no more than 3 C. This article discusses different aspects of the debate. 9 refs., 1 fig.

Broecker, W. [Columbia Univ., Palisades, NY (United States)

1996-06-28

252

Simple models of tropical plumes  

E-print Network

. Tropical plumes and related phenomena. . . , . III MODEL AND METHOD IV SIMULATIONS AND DISCUSSION a. Overview 16 b. Simulation 0 ? zonally asymmetric initial state. . . . . c. Simulation 1 ? a tropical plume. . . d. Simulation 2 ? forcing 4' poleward... (dashed, interval 107 m2 s-1) at day 8. . 32 26 Simulation 2 divergence (interval 10-s s-1, dashed & 0) at day 8. . . . 32 27 Simulation 2 smoothed Rossby source (interval 10-~ s-1 day-1, dashed & 0) at day 8. . . . . 33 28 Simulation 2 height (solid...

Carrie, Gordon David, d 1960-

1994-01-01

253

Tropical cyclone-ocea~ interactions Isaac Ginis  

E-print Network

I' I I I· f" I' Ii I I Tropical cyclone-ocea~ interactions Isaac Ginis Graduate School a/Oceanography, University 0/Rhode Island, USA. Abstract The advent of numerical weather prediction tropical cyclone models has demonstrably improved the forecasting of tropical cyclones during recent decades. But to establish

Rhode Island, University of

254

Reflections on the tropical deforestation crisis  

Microsoft Academic Search

Tropical forests do far more than sustain biodiversity; they are homes to indigenous peoples, pharmacopeias of natural products, and provide vital ecosystem services, such as flood amelioration and soil conservation. At regional and global scales, tropical forests also have a major influence on carbon storage and climate. I highlight these benefits, then assess the pattern and pace of tropical forest

William F. Laurance

1999-01-01

255

OCEAN-ATMOSPHERE INTERACTION AND TROPICAL CLIMATE  

E-print Network

1 OCEAN-ATMOSPHERE INTERACTION AND TROPICAL CLIMATE Shang-Ping Xie International Pacific Research Meteorology Keywords: ocean-atmospheric feedback, tropical climate, climate variability, Intertropical in the structure of tropical climate. Ocean-atmosphere interaction research has experienced rapid growth

Xie, Shang-Ping

256

An unusual presentation of tropical pyomyositis.  

PubMed

Tropical pyomyositis is a primary pyogenic infection of skeletal muscle, often caused by Staphylococcus aureus. The most common presentation of tropical pyomyositis is that of multiple acute abscesses with fever. Hepatitis is a rare manifestation of this disease. We report a case of tropical pyomyositis who presented with hepatic encephalopathy leading to initial diagnostic dilemma. PMID:16114167

Sudha, V; Abhishek, M; Shashikiran, U; Annappa, K; Mukhyaprana, M P

2005-06-01

257

OCEAN RESPONSE TO TROPICAL CYCLONE Isaac Ginis  

E-print Network

Chapter 5 OCEAN RESPONSE TO TROPICAL CYCLONE Isaac Ginis fIbis chapter benefited from careful impact of sea-surface temperature (SST) on the genesis and intensification of tropical cyclones has long been recognized (Palmen 1948; Miller 1958). It is well known that tropical cyclones climatologically

Rhode Island, University of

258

Historical Global Tropical Cyclone Landfalls* JESSICA WEINKLE  

E-print Network

Historical Global Tropical Cyclone Landfalls* JESSICA WEINKLE Center for Science and Technology February 2012) ABSTRACT In recent decades, economic damage from tropical cyclones (TCs) around the world, etc.) in locations prone to tropical cyclone landfalls, rather than by changes in annual storm

Colorado at Boulder, University of

259

Tropical Fruit Ambrosia Makes 6 servings  

E-print Network

Tropical Fruit Ambrosia Makes 6 servings 1 jar (26 oz.) mixed tropical fruit, drained 1 large banana, sliced 1 cup low-fat yogurt ¼ tsp. finely grated lime zest 2 Tbsp. fresh lime juice ¼ cup flaked coconut Lettuce leaves Directions: 1. In a large bowl, combine the tropical fruit and banana. 2

Florida, University of

260

Linear independence over tropical semirings and beyond  

Microsoft Academic Search

We investigate different notions of linear independence and of matrix rank that are relevant for max-plus or tropical semirings. The factor rank and tropical rank have already received attention, we compare them with the ranks defined in terms of signed tropical determinants or arising from a notion of linear independence introduced by Gondran and Minoux. To do this, we revisit

Marianne Akian; Stephane Gaubert; Alexander Guterman

2008-01-01

261

Mammary gland neoplasia in long-term rodent studies.  

PubMed Central

Breast cancer, the most frequent spontaneous malignancy diagnosed in women in the western world, is continuously increasing in incidence in industrialized nations. Although breast cancer develops in women as the result of a combination of external and endogenous factors such as exposure to ionizing radiation, diet, socioeconomic status, and endocrinologic, familial, or genetic factors, no specific etiologic agent(s) or the mechanisms responsible of the disease has been identified as yet. Thus, experimental models that exhibit the same complex interactions are needed for testing various mechanisms and for assessing the carcinogenic potential of given chemicals. Rodent mammary carcinomas represent such a model to a great extent because, in these species, mammary cancer is a multistep complex process that can be induced by either chemicals, radiation, viruses, or genetic factors. Long-term studies in rodent models have been particularly useful for dissecting the initiation, promotion, and progression steps of carcinogenesis. The susceptibility of the rodent mammary gland to develop neoplasms has made this organ a unique target for testing the carcinogenic potential of specific genotoxic chemicals and environmental agents. Mammary tumors induced by indirect- or direct-acting carcinogens such as 7, 12-dimethlbenz(a)anthracene or N-methyl-N-nitrosourea are, in general, hormone dependent adenocarcinomas whose incidence, number of tumors per animal, tumor latency, and tumor type are influenced by the age, reproductive history, and endocarinologic milieu of the host at the time of carcinogen exposure. Rodent models are informative in the absence of human data. They have provided valuable information on the dose and route of administration to be used and optimal host conditions for eliciting maximal tumorigenic response. Studies of the influence of normal gland development on the pathogenesis of chemically induced mammary carcinomas have clarified the role of differentiation in cancer initiation. Comparative studies with the development of the human breast and the pathogenesis of breast cancer have contributed to validate rodent-to-human extrapolations. However, it has not been definitively established what type of information is necessary for human risk assessment, whether currently toxicity testing methodologies are sufficient for fulfilling those needs, or whether treatment-induced tumorigenic responses in rodents are predictive of potential human risk. An alternative to the traditional bioassays are mechanism-based toxicology and molecular and cellular approaches, combined with comparative in vitro systems. These approaches might allow the rapid screen of chemicals for setting priorities for further studies to determine the dose-response relationship for chemical effects at low doses, to assess effects other than mutagenesis and/or tumorigenesis, or to establish qualitative and quantitative relationships of biomarkers to toxic effects. Until there is enough information on the predictive value of mechanism-based toxicology for risk assessment, this approach should be used in conjunction with and validated by the traditional in vivo long-term bioassays. Images Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. A Figure 7. B Figure 8. A Figure 8. B Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23. Figure 24. Figure 25. Figure 26. PMID:8899375

Russo, I H; Russo, J

1996-01-01

262

Unintentional wildlife poisoning and proposals for sustainable management of rodents.  

PubMed

In Europe, bromadiolone, an anticoagulant rodenticide authorized for plant protection, may be applied intensively in fields to control rodents. The high level of poisoning of wildlife that follows such treatments over large areas has been frequently reported. In France, bromadiolone has been used to control water voles (Arvicola terrestris) since the 1980s. Both regulation and practices of rodent control have evolved during the last 15 years to restrict the quantity of poisoned bait used by farmers. This has led to a drastic reduction of the number of cases of poisoned wildlife reported by the French surveillance network SAGIR. During the autumn and winter 2011, favorable weather conditions and high vole densities led to the staging of several hundreds of Red Kites (Milvus milvus) in the Puy-de-Dôme department (central France). At the same time, intensive treatments with bromadiolone were performed in this area. Although no misuse has been mentioned by the authorities following controls, 28 Red Kites and 16 Common Buzzards (Buteo buteo) were found dead during surveys in November and December 2011. For all these birds, poisoning by bromadiolone as the main cause of death was either confirmed or highly suspected. Other observations suggest a possible impact of bromadiolone on the breeding population of Red Kites in this area during the spring 2011. French regulation of vole control for plant protection is currently under revision, and we believe this event calls for more sustainable management of rodent outbreaks. Based on large-scale experiments undertaken in eastern France, we propose that direct control of voles at low density (with trapping or limited chemical treatments) and mechanical destruction of vole tunnels, mole control, landscape management, and predator fostering be included in future regulation because such practices could help resolve conservation and agricultural issues. PMID:24405288

Coeurdassier, Michael; Riols, Romain; Decors, Anouk; Mionnet, Aymeric; David, Fabienne; Quintaine, Thomas; Truchetet, Denis; Scheifler, Renaud; Giraudoux, Patrick

2014-04-01

263

[11C]Rhodamine-123: synthesis and biodistribution in rodents  

PubMed Central

Introduction Rhodamine-123 is a known substrate for the efflux transporter, P-glycoprotein (P-gp). We wished to assess whether rhodamine-123 might serve as a useful substrate for developing probes for imaging efflux transporters in vivo with positron emission tomography (PET). For this purpose, we aimed to label rhodamine-123 with carbon-11 (t1/2 = 20.4 min) and to study its biodistribution in rodents. Methods [11C]Rhodamine-123 was prepared by treating rhodamine-110 (desmethyl-rhodamine-123), with [11C]methyl iodide. The biodistribution of this radiotracer was studied with PET in wild-type mice and rats, in efflux transporter knockout mice, in wild-type rats pretreated with DCPQ (an inhibitor of P-gp) or with cimetidine (an inhibitor of organic cation transporters; OCT), and in P-gp knockout mice pretreated with cimetidine. Unchanged radiotracer in forebrain, plasma and peripheral tissues was also measured ex vivo at 30 min after radiotracer administration to wild-type and efflux transporter knockout rodents. Results [11C]Rhodamine-123 was obtained in 4.4% decay-corrected radiochemical yield from cyclotron-produced [11C]carbon dioxide. After intravenous administration of [11C]rhodamine-123 to wild-type rodents, PET and ex vivo measurements showed radioactivity uptake was very low in brain, but relatively high in some other organs such as heart, and especially liver and kidney. Inhibition of P-gp increased uptake in brain, heart, kidney and liver, but only by up to twofold. Secretion of radioactivity from kidney was markedly reduced by OCT knockout or pretreatment with cimetidine. Conclusions [11C]Rhodamine-123 was unpromising as a PET probe for P-gp function and appears to be a strong substrate of OCT in kidney. Cimetidine appears effective for blocking OCT in kidney in vivo. PMID:22898316

Bao, Xiaofeng; Lu, Shuiyu; Liow, Jeih-San; Morse, Cheryl L.; Anderson, Kacey; Zoghbi, Sami S.; Innis, Robert B.; Pike, Victor W.

2012-01-01

264

Algorithmically generated rodent hepatic vascular trees in arbitrary detail.  

PubMed

Physiologically realistic geometric models of the vasculature in the liver are indispensable for modelling hepatic blood flow, the main connection between the liver and the organism. Current in vivo imaging techniques do not provide sufficiently detailed vascular trees for many simulation applications, so it is necessary to use algorithmic refinement methods. The method of Constrained Constructive Optimization (CCO) (Schreiner et al., 2006) is well suited for this purpose. Its results after calibration have been previously compared to experimentally acquired human vascular trees (Schwen and Preusser, 2012). The goal of this paper is to extend this calibration to the case of rodents (mice and rats), the most commonly used animal models in liver research. Based on in vivo and ex vivo micro-CT scans of rodent livers and their vasculature, we performed an analysis of various geometric features of the vascular trees. Starting from pruned versions of the original vascular trees, we applied the CCO procedure and compared these algorithmic results to the original vascular trees using a suitable similarity measure. The calibration of the postprocessing improved the algorithmic results compared to those obtained using standard CCO. In terms of angular features, the average similarity increased from 0.27 to 0.61, improving the total similarity from 0.28 to 0.40. Finally, we applied the calibrated algorithm to refine measured vascular trees to the (higher) level of detail desired for specific applications. Having successfully adapted the CCO algorithm to the rodent model organism, the resulting individual-specific refined hepatic vascular trees can now be used for advanced modeling involving, e.g., detailed blood flow simulations. PMID:25451523

Schwen, Lars Ole; Wei, Weiwei; Gremse, Felix; Ehling, Josef; Wang, Lei; Dahmen, Uta; Preusser, Tobias

2015-01-21

265

A protocol for a lung neovascularization model in rodents  

PubMed Central

By providing insight into the cellular events of vascular injury and repair, experimental model systems seek to promote timely therapeutic strategies for human disease. The goal of many current studies of neovascularization is to identify cells critical to the process and their role in vascular channel assembly. We propose here a protocol to analyze, in an in vivo rodent model, vessel and capillary remodeling (reorganization and growth) in the injured lung. Sequential analyses of stages in the assembly of vascular structures, and of relevant cell types, provide further opportunities to study the molecular and cellular determinants of lung neovascularization. PMID:18323809

Jones, Rosemary C; Capen, Diane E; Petersen, Bodil; Jain, Rakesh K; Duda, Dan G

2009-01-01

266

Pulmonary Toxicity Studies of Lunar Dusts in Rodents  

NASA Technical Reports Server (NTRS)

NASA will build an outpost on the lunar surface for long-duration human habitation and research. The surface of the Moon is covered by a layer of fine, reactive dust, and the living quarters in the lunar outpost are expected to be contaminated by lunar dust. NASA established the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) to evaluate the risk of exposure to the dust and to establish safe exposure limits for astronauts working in the lunar habitat. Because the toxicity of lunar dust is not known, LADTAG has recommended investigating its toxicity in the lungs of laboratory animals. After receiving this recommendation, NASA directed the JSC Toxicology Laboratory to determine the pulmonary toxicity of lunar dust in exposed rodents. The rodent pulmonary toxicity studies proposed here are the same as those proposed by the LADTAG. Studies of the pulmonary toxicity of a dust are generally done first in rodents by intratracheal instillation (ITI). This toxicity screening test is then followed by an inhalation study, which requires much more of the test dust and is labor intensive. We succeeded in completing an ITI study on JSC-1 lunar dust simulant in mice (Lam et al., Inhalation Toxicology 14:901-916, 2002, and Inhalation Toxicology 14: 917-928, 2002), and have conducted a pilot ITI study to examine the acute toxicity of an Apollo lunar (highland) dust sample. Preliminary results obtained by examining lung lavage fluid from dust-treated mice show that lunar dust was somewhat toxic (more toxic than TiO2, but less than quartz dust). More extensive studies have been planned to further examine lung lavage fluid for biomarkers of toxicity and lung tissues for histopathological lesions in rodents exposed to aged and activated lunar dust samples. In these studies, reference dusts (TiO2 and quartz) of known toxicities and have industrial exposure limits will be studied in parallel so the relative toxicity of lunar dust can be determined. The ITI results will also be useful for choosing an exposure concentration for the animal inhalation study on a selected lunar dust sample, which is included as a part of this proposal. The animal inhalation exposure will be conducted with lunar dust simulant prior to the study with the lunar dust. The simulant exposure will ensure that the study techniques used with actual lunar dust will be successful. The results of ITI and inhalation studies will reveal the toxicological risk of exposures and are essential for setting exposure limits on lunar dust for astronauts living in the lunar habitat.

Lam, Chiu-wing; James, John T.; Taylor, Larry

2008-01-01

267

Hemorrhagic gastritis in free-living rodents in Idaho.  

PubMed

Between February 1992 and March 1994, four species of rodent from the Snake River Birds of Prey Area near Boise, Idaho (USA) were necropsied. Hemorrhagic gastritis was observed in 16 of 131 Townsend's ground squirrels (Spermophilus townsendii), one of 11 Ord's kangaroo rats (Dipodomys ordii) and the one Great Basin pocket mouse (Perognathus parvus) evaluated. No lesions were observed in 14 white-footed deer mice (Peromyscus maniculatus). Tissue from one Townsend's ground squirrel was negative for Helicobacter sp.-like bacteria. PMID:9359067

Wilber, P G; Duszynski, D W; Van Horne, B

1996-10-01

268

Nonhuman gamblers: lessons from rodents, primates, and robots  

PubMed Central

The search for neuronal and psychological underpinnings of pathological gambling in humans would benefit from investigating related phenomena also outside of our species. In this paper, we present a survey of studies in three widely different populations of agents, namely rodents, non-human primates, and robots. Each of these populations offers valuable and complementary insights on the topic, as the literature demonstrates. In addition, we highlight the deep and complex connections between relevant results across these different areas of research (i.e., cognitive and computational neuroscience, neuroethology, cognitive primatology, neuropsychiatry, evolutionary robotics), to make the case for a greater degree of methodological integration in future studies on pathological gambling. PMID:24574984

Paglieri, Fabio; Addessi, Elsa; De Petrillo, Francesca; Laviola, Giovanni; Mirolli, Marco; Parisi, Domenico; Petrosino, Giancarlo; Ventricelli, Marialba; Zoratto, Francesca; Adriani, Walter

2014-01-01

269

Rodent Models and Behavioral Outcomes of Cervical Spinal Cord Injury  

PubMed Central

Rodent spinal cord injury (SCI) models have been developed to examine functional and physiological deficits after spinal cord injury with the hope that these models will elucidate information about human SCI. Models are needed to examine possible treatments and to understand histopathology after SCI; however, they should be considered carefully and chosen based on the goals of the study being performed. Contusion, compression, transection, and other models exist and have the potential to reveal important information about SCI that may be related to human SCI and the outcomes of treatment and timing of intervention. PMID:25309824

Geissler, Sydney A.; Schmidt, Christine E.; Schallert, Timothy

2014-01-01

270

Placentation in Sigmodontinae: a rodent taxon native to South America  

PubMed Central

Background Sigmodontinae, known as "New World rats and mice," is a large subfamily of Cricetidae for which we herein provide the first comprehensive investigation of the placenta. Methods Placentas of various gestational ages ranging from early pregnancy to near term were obtained for five genera, i.e. Necromys, Euryoryzomys, Cerradomys, Hylaeamys, and Oligoryzomys. They were investigated by means of histology, immunohistochemistry, a proliferation marker, DBA-lectin staining and transmission electron microscopy. Results The chorioallantoic placenta was organized in a labyrinthine zone, spongy zone and decidua and an inverted yolk sac persisted until term. The chorioallantoic placenta was hemotrichorial. The interhemal barrier comprised fetal capillary endothelium and three layers of trophoblast, an outermost, cellular layer and two syncytial ones, with interspersed trophoblast giant cells (TGC). In addition, accumulations of TGC occurred below Reichert's membrane. The junctional zone contained syncytial trophoblast, proliferative cellular trophoblast, glycogen cells and TGC that were situated near to the maternal blood channels. In three of the genera, TGC were also accumulated in distinct areas at the placental periphery. PAS-positive glycogen cells derived from the junctional zone invaded the decidua. Abundant maternal uNK cells with positive response to PAS, vimentin and DBA-lectin were found in the decidua. The visceral yolk sac was completely inverted and villous. Conclusion The general aspect of the fetal membranes in Sigmodontinae resembled that found in other cricetid rodents. Compared to murid rodents there were larger numbers of giant cells and in some genera these were seen to congregate at the periphery of the placental disk. Glycogen cells were found to invade the decidua but we did not identify trophoblast in the walls of the deeper decidual arteries. In contrast these vessels were surrounded by large numbers of uNK cells. This survey of wild-trapped specimens from five genera is a useful starting point for the study of placentation in an important subfamily of South American rodents. We note, however, that some of these rodents can be captive bred and recommend that future studies focus on the study of time dated pregnancies. PMID:21518439

2011-01-01

271

Tropical Depression Kyle, October 10, 2002  

NSDL National Science Digital Library

Tropical Depression Kyle is expected to reach the northeast Florida coast in 24 hours. It is currently packing sustained winds of 30 mph. The storm developed on September 20, 2002 and has been classified as a sub-tropical depression, tropical storm, hurricane, tropical storm, and now a tropical depression. The visualization zooms down to the storm and then shows the overall rain structure of Kyle. Yellow represents areas where at least 0.5 inches of rain fell per hour. Green shows at least 1.0 inch of rain, and red depicts more than 2.0 inches of rain per hour.

Perkins, Lori; Halverson, Jeff

2002-10-10

272

Tropical Storm Allison Progression (WMS)  

NSDL National Science Digital Library

Tropical Storm Allison began just five days into the 2001 hurricane season. Allison formed in the warm waters of the Gulf of Mexico, and dumped an enormous amount of rain on Texas, Louisiana, Florida, and other states in the southeastern United States.

Sokolowsky, Eric; Perkins, Lori; Kuring, Norman; Feldman, Gene

2004-03-11

273

Ecotoxicology of tropical marine ecosystems  

Microsoft Academic Search

The negative effects of chemical contaminants on tropical marine ecosystems are of increasing concern as human populations expand adjacent to these communities. Watershed streams and ground water carry a variety of chemicals from agricultural, industrial, and domestic activities, while winds and currents transport pollutants from atmospheric and oceanic sources to these coastal ecosystems. The implications of the limited information available

Esther C. Peters; Nancy J. Gassman; Julie C. Firman; Robert H. Richmond; Elizabeth A. Power

1997-01-01

274

Freshwater Turtles of Tropical Australia  

E-print Network

Joseph of the Australian National Wildlife Collection for freely providing museum records, and the many for freshwater turtles of tropical Australia and to construct and populate a database to house the information,871 records from the UC Turtle Tissue Database. Most species distributions were very well supported by good

Canberra, University of

275

Tropical Biological Drawings with Notes.  

ERIC Educational Resources Information Center

The annotated illustrations of biological specimens useful for illustrating the "tropical" topics dealt with in African secondary school biology courses are designed to serve a two-fold purpose. The diagrams are intended to show the pupil the structures he should be looking for in his laboratory work, with the textual material being an addition to…

Mitchelmore, June A.

276

Tropical Cyclone Report Hurricane Katrina  

E-print Network

1 Tropical Cyclone Report Hurricane Katrina 23-30 August 2005 Richard D. Knabb, Jamie R. Rhome, and damage cost estimates Katrina was an extraordinarily powerful and deadly hurricane that carved a wide deadliest hurricanes to ever strike the United States. Katrina first caused fatalities and damage

277

NONARCHIMEDEAN AMOEBAS AND TROPICAL VARIETIES  

E-print Network

NON­ARCHIMEDEAN AMOEBAS AND TROPICAL VARIETIES MANFRED EINSIEDLER, MIKHAIL KAPRANOV, AND DOUGLAS LIND Abstract. We study the non­archimedean counterpart to the complex amoeba of an algebraic variety and a recent result of Conrad we prove that the amoeba of an irreducible variety is connected. We introduce

Lind, Douglas A.

278

Black Swan Tropical Cyclones  

NASA Astrophysics Data System (ADS)

Virtually all assessments of tropical cyclone risk are based on historical records, which are limited to a few hundred years at most. Yet stronger TCs may occur in the future and at places that have not been affected historically. Such events lie outside the realm of historically based expectations and may have extreme impacts. Their occurrences are also often made explainable after the fact (e.g., Hurricane Katrina). We nickname such potential future TCs, characterized by rarity, extreme impact, and retrospective predictability, "black swans" (Nassim Nicholas Taleb, 2007). As, by definition, black swan TCs have yet to happen, statistical methods that solely rely on historical track data cannot predict their occurrence. Global climate models lack the capability to predict intense storms, even with a resolution as high as 14 km (Emanuel et al. 2010). Also, most dynamic downscaling methods (e.g., Bender et al. 2010) are still limited in horizontal resolution and are too expensive to implement to generate enough events to include rare ones. In this study, we apply a simpler statistical/deterministic hurricane model (Emanuel et al. 2006) to simulate large numbers of synthetic storms under a given (observed or projected) climate condition. The method has been shown to generate realistic extremes in various basins (Emanuel et al. 2008 and 2010). We also apply a hydrodynamic model (ADCIRC; Luettich et al. 1992) to simulate the storm surges generated by these storms. We then search for black swan TCs, in terms of the joint wind and surge damage potential, in the generated large databases. Heavy rainfall is another important TC hazard and will be considered in a future study. We focus on three areas: Tampa Bay in the U.S., the Persian Gulf, and Darwin in Australia. Tampa Bay is highly vulnerable to storm surge as it is surrounded by shallow water and low-lying lands, much of which may be inundated by a storm tide of 6 m. High surges are generated by storms with a broad spectrum of characteristics in our synthetic database, although no large surge has been recorded historically as only one moderate storm passed by the area. Tampa black swans are identified as those that move northward parallel to the west Florida coast with high intensities and resonant with the Florida-shelf edge waves to generate extreme surges up to 10 m in Tampa Bay. The Arabian Sea area has sea surface temperatures warm enough to support the development of severe TCs, but TC development has been limited by low humidity and high wind shear, and only one recorded TC (super cyclonic storm Gonu in 2007) moved close to the Persian Gulf, making landfall in Oman and Iran. Our analysis shows that black swan TCs can originate within the Persian Gulf and make landfall with high intensities in populous places; extreme surges over 9 m for Abu Dubai and Doha and over 7 m for Dubai are possible. Darwin experienced immense devastation from Cyclone Tracy of 1974, but the damage was mainly due to the strong winds (the surge was only about 1.6 m). Our analysis includes extremely intense black swan TCs that make landfall just south of Darwin, generating surges above 10 m; these results may prompt the city to reconsider its TC risk. We are currently analyzing the join probability of the extreme wind and surge of these black swan TCs to more clearly assess their full damage potentials.

Emanuel, K.; Lin, N.

2012-12-01

279

Genome Diversification Mechanism of Rodent and Lagomorpha Chemokine Genes  

PubMed Central

Chemokines are a large family of small cytokines that are involved in host defence and body homeostasis through recruitment of cells expressing their receptors. Their genes are known to undergo rapid evolution. Therefore, the number and content of chemokine genes can be quite diverse among the different species, making the orthologous relationships often ambiguous even between closely related species. Given that rodents and rabbit are useful experimental models in medicine and drug development, we have deduced the chemokine genes from the genome sequences of several rodent species and rabbit and compared them with those of human and mouse to determine the orthologous relationships. The interspecies differences should be taken into consideration when experimental results from animal models are extrapolated into humans. The chemokine gene lists and their orthologous relationships presented here will be useful for studies using these animal models. Our analysis also enables us to reconstruct possible gene duplication processes that generated the different sets of chemokine genes in these species. PMID:23991422

Shibata, Kanako; Yoshie, Osamu; Tanase, Sumio

2013-01-01

280

Molecular detection of bacterial contamination in gnotobiotic rodent units  

PubMed Central

Gnotobiotic rodents provide an important technique to study the functional roles of commensal bacteria in host physiology and pathophysiology. To ensure sterility, these animals must be screened frequently for contamination. The traditional screening approaches of culturing and Gram staining feces have inherent limitations, as many bacteria are uncultivable and fecal Gram stains are difficult to interpret. Thus, we developed and validated molecular methods to definitively detect and identify contamination in germ-free (GF) and selectively colonized animals. Fresh fecal pellets were collected from rodents housed in GF isolators, spontaneously contaminated ex-GF isolators, selectively colonized isolators and specific pathogen-free (SPF) conditions. DNA isolated from mouse and rat fecal samples was amplified by polymerase chain reaction (PCR) and subjected to quantitative PCR (qPCR) using universal primers that amplify the 16S rRNA gene from all bacterial groups. PCR products were sequenced to identify contaminating bacterial species. Random amplification of polymorphic DNA (RAPD) PCR profiles verified bacterial inoculation of selectively colonized animals. These PCR techniques more accurately detected and identified GF isolator contamination than current standard approaches. These molecular techniques can be utilized to more definitively screen GF and selectively colonized animals for bacterial contamination when Gram stain and/or culture results are un-interpretable or inconsistent. PMID:23887190

Packey, Christopher D; Shanahan, Michael T; Manick, Sayeed; Bower, Maureen A; Ellermann, Melissa; Tonkonogy, Susan L; Carroll, Ian M; Sartor, R Balfour

2013-01-01

281

Hearing in prairie dogs: transition between surface and subterranean rodents.  

PubMed

Behavioral audiograms were determined for four black-tailed and one white-tailed prairie dogs (Cynomys ludovicianus and C. leucurus) using a conditioned avoidance procedure. The hearing of black-tailed prairie dogs ranges from 29 Hz to 26 kHz and that of the white-tailed prairie dog from 44 Hz to 26 kHz (at sound pressure levels of 60 dB). Both species have good low-frequency hearing, especially black-tailed prairie dogs which can hear as low as 4 Hz and are more sensitive than any other rodent yet tested at frequencies below 63 Hz. In contrast, prairie dogs are relatively insensitive in their midrange and have poor high-frequency hearing. It is suggested that the reduced midrange sensitivity and high-frequency hearing are related to their adaptation to an underground lifestyle with its reduced selective pressure for sound localization. In this respect they appear to be intermediate between the more exclusively subterranean rodents (such as gophers and mole rats) and surface dwellers (such as chinchillas and kangaroo rats). PMID:8188546

Heffner, R S; Heffner, H E; Contos, C; Kearns, D

1994-03-01

282

Studying Autism in Rodent Models: Reconciling Endophenotypes with Comorbidities  

PubMed Central

Autism spectrum disorder (ASD) patients commonly exhibit a variety of comorbid traits including seizures, anxiety, aggressive behavior, gastrointestinal problems, motor deficits, abnormal sensory processing, and sleep disturbances for which the cause is unknown. These features impact negatively on daily life and can exaggerate the effects of the core diagnostic traits (social communication deficits and repetitive behaviors). Studying endophenotypes relevant to both core and comorbid features of ASD in rodent models can provide insight into biological mechanisms underlying these disorders. Here we review the characterization of endophenotypes in a selection of environmental, genetic, and behavioral rodent models of ASD. In addition to exhibiting core ASD-like behaviors, each of these animal models display one or more endophenotypes relevant to comorbid features including altered sensory processing, seizure susceptibility, anxiety-like behavior, and disturbed motor functions, suggesting that these traits are indicators of altered biological pathways in ASD. However, the study of behaviors paralleling comorbid traits in animal models of ASD is an emerging field and further research is needed to assess altered gastrointestinal function, aggression, and disorders of sleep onset across models. Future studies should include investigation of these endophenotypes in order to advance our understanding of the etiology of this complex disorder. PMID:23898259

Argyropoulos, Andrew; Gilby, Krista L.; Hill-Yardin, Elisa L.

2013-01-01

283

Chromosomal instability in rodents caused by pollution from Baikonur cosmodrome.  

PubMed

An assessment of the health status of ecosystems exposed to man-made pollution is a vital issue for many countries. Particularly it concerns the consequences of contamination caused by the activity of the space industry. Each rocket launch is accompanied by the introduction of parts of the rocket propellant into the environment. This study aims to scrutinize the effect of the components of rocket fuel on the induction of lipid peroxidation and chromosomal aberrations on rodents inhabiting the area exposed to pollution from Baikonur cosmodrome. The results showed the increase of the level of lipid hydroperoxide and malondialdehyde in the livers of Citellus pygmaeus Pallas and Mus musculus L., which indicates an augmentation of free radical activity and DNA damage. The cytogenetic analysis of bone marrow cells revealed that the frequency of chromosomal aberrations was a few times higher in the rodents from contaminated territory. The signs of oxidative stress and high level of chromosomal aberrations indicate the environmental impact of the cosmodrome, and its possible toxic and mutagenic effects on ecosystems. PMID:24990120

Kolumbayeva, Saule; Begimbetova, Dinara; Shalakhmetova, Tamara; Saliev, Timur; Lovinskaya, Anna; Zhunusbekova, Benazir

2014-09-01

284

Holocene Vegetation History from Fossil Rodent Middens near Arequipa, Peru  

NASA Astrophysics Data System (ADS)

Rodent (Abrocoma, Lagidium, Phyllotis) middens collected from 2350 to 2750 m elevation near Arequipa, Peru (16°S), provide an ?9600-yr vegetation history of the northern Atacama Desert, based on identification of >50 species of plant macrofossils. These midden floras show considerable stability throughout the Holocene, with slightly more mesophytic plant assemblages in the middle Holocene. Unlike the southwestern United States, rodent middens of mid-Holocene age are common. In the Arequipa area, the midden record does not reflect any effects of a mid-Holocene mega drought proposed from the extreme lowstand (100 m below modern levels, >6000 to 3500 yr B.P.) of Lake Titicaca, only 200 km east of Arequipa. This is perhaps not surprising, given other evidence for wetter summers on the Pacific slope of the Andes during the middle Holocene as well as the poor correlation of summer rainfall among modern weather stations in the central Andes-Atacama Desert. The apparent difference in paleoclimatic reconstructions suggests that it is premature to relate changes observed during the Holocene to changes in El Niño Southern Oscillation modes.

Holmgren, Camille A.; Betancourt, Julio L.; Rylander, Kate Aasen; Roque, Jose; Tovar, Oscar; Zeballos, Horacio; Linares, Eliana; Quade, Jay

2001-09-01

285

Population ecology of hantavirus rodent hosts in southern Brazil.  

PubMed

In this study we analyze population dynamics of hantavirus rodent hosts and prevalence of infection over a 2-year period in Southern Brazil, a region with a high incidence of hantavirus pulmonary syndrome. The 14 small mammal species captured were composed of 10 rodents and four marsupials, the six most abundant species being Akodon serrensis, Oxymycterus judex, Akodon montensis, Akodon paranaensis, Oligoryzomys nigripes, and Thaptomys nigrita. These species displayed a similar pattern with increasing population sizes in fall/winter caused by recruitment and both, increase in reproductive activity and higher hantavirus prevalence in spring/summer. Specific associations between A. montensis/Jaborá Virus (JABV) and O. nigripes/Juquitiba-like Virus (JUQV-like) and spillover infections between A. paranaensis/JABV, A. serrensis/JABV, and A. paranaensis/JUQV-like were observed. Spillover infection in secondary hosts seems to play an important role in maintaining JABV and JUQV-like in the hantavirus sylvatic cycle mainly during periods of low prevalence in primary hosts. PMID:24935954

Teixeira, Bernardo R; Loureiro, Nathalie; Strecht, Liana; Gentile, Rosana; Oliveira, Renata C; Guterres, Alexandro; Fernandes, Jorlan; Mattos, Luciana H B V; Raboni, Sonia M; Rubio, Giselia; Bonvicino, Cibele R; dos Santos, Claudia N Duarte; Lemos, Elba R S; D'Andrea, Paulo S

2014-08-01

286

Seasonal variation in telomere length of a hibernating rodent.  

PubMed

Small hibernating rodents have greater maximum lifespans and hence appear to age more slowly than similar-sized non-hibernators. We tested for a direct effect of hibernation on somatic maintenance and ageing by measuring seasonal changes in relative telomere length (RTL) in the edible dormouse Glis glis. Average RTL in our population did not change significantly over the hibernation season, and a regression model explaining individual variation in post-hibernation RTL suggested a significant negative effect of the reduction in body mass over the inactive hibernation period (an index of time spent euthermic), supporting the idea that torpor slows ageing. Over the active season, RTL on average decreased in sub-adults but increased in adults, supporting previous findings of greater telomere shortening at younger ages. Telomere length increase might also have been associated with reproduction, which occurred only in adults. Our study reveals how seasonal changes in physiological state influence the progress of life-history traits, such as somatic maintenance and ageing, in a small hibernating rodent. PMID:23389666

Turbill, Christopher; Ruf, Thomas; Smith, Steve; Bieber, Claudia

2013-04-23

287

Modelling cognitive affective biases in major depressive disorder using rodents.  

PubMed

Major depressive disorder (MDD) affects more than 10% of the population, although our understanding of the underlying aetiology of the disease and how antidepressant drugs act to remediate symptoms is limited. Major obstacles include the lack of availability of good animal models that replicate aspects of the phenotype and tests to assay depression-like behaviour in non-human species. To date, research in rodents has been dominated by two types of assays designed to test for depression-like behaviour: behavioural despair tests, such as the forced swim test, and measures of anhedonia, such as the sucrose preference test. These tests have shown relatively good predictive validity in terms of antidepressant efficacy, but have limited translational validity. Recent developments in clinical research have revealed that cognitive affective biases (CABs) are a key feature of MDD. Through the development of neuropsychological tests to provide objective measures of CAB in humans, we have the opportunity to use 'reverse translation' to develop and evaluate whether similar methods are suitable for research into MDD using animals. The first example of this approach was reported in 2004 where rodents in a putative negative affective state were shown to exhibit pessimistic choices in a judgement bias task. Subsequent work in both judgement bias tests and a novel affective bias task suggest that these types of assay may provide translational methods for studying MDD using animals. This review considers recent work in this area and the pharmacological and translational validity of these new animal models of CABs. PMID:24467454

Hales, Claire A; Stuart, Sarah A; Anderson, Michael H; Robinson, Emma S J

2014-10-01

288

Rodent ectoparasites from two locations in northwestern Florida.  

PubMed

From Feb.-Apr. 1999, 19 species of ectoparasitic arthropods (2 sucking lice, 4 fleas, 4 ticks, 2 mesostigmatid mites, 5 chiggers, 2 fur mites) were recovered from 106 rodents belonging to 5 species (cotton mouse, Peromyscus gossypinus, n = 64; cotton rat, Sigmodon hispidus, n = 23; eastern woodrat, Neotoma floridana, n = 9; golden mouse, Ochrotomys nuttalli, n = 9; eastern gray squirrel, Sciurus carolinensis, n = 1) at Tall Timbers Research Station, Leon County, Florida. During the same period, 13 species of ectoparasites (2 sucking lice, 1 flea, 3 ticks, 3 mesostigmatid mites, 2 chiggers, 2 fur mites) were recovered from 57 rodents belonging to 3 species (S. hispidus, n = 40; black rat, Rattus rattus, n = 16; S. carolinensis, n = 1) from Panama City, Bay County, Florida. Noteworthy ectoparasite records include Ixodes minor from both sites, which extends the known geographical range of this tick, and Stenoponia americana from Tall Timbers that represents the second documented Florida record of this flea. Potential tick vectors (Dermacentor variabilis and Ixodes scapularis) of zoonotic pathogens (Rickettsia rickettsii and Borrelia burgdorferi) were collected at both sites. On S. hispidus, fleas were more prevalent at Tall Timbers but sucking lice, chiggers, ticks, mesostigmatid and listrophorid mites all were more prevalent at the Panama City site. Arthropods recovered from arboreal nests (n = 3) of O. nuttalli at Tall Timbers included 3 species of ectoparasites (1 tick, 2 laelapid mites). PMID:11217221

Durden, L A; Hu, R; Oliver, J H; Cilek, J E

2000-12-01

289

Management of Rodent Exposure and Allergy in the Pediatric Population  

PubMed Central

Although rodent allergy has long been recognized as an occupational disease, it has only been in the past decade that it has been recognized as a community-based disease that affects children. Most homes in the US have detectable mouse allergen, but the concentrations in inner-city homes are orders of magnitude higher than those found in suburban homes. Home mouse allergen exposure has been linked to sensitization to mouse, and children with asthma who are both sensitized and exposed to high mouse allergen concentrations at home are at greater risk for symptoms, exacerbations and reduced lung function. Rat allergen is found primarily in inner-city homes and has also been linked to asthma morbidity among sensitized children. The objective of this review is to summarize the scientific literature on rodents and their allergens, the effects of exposure to these allergens on allergic respiratory disease, and to make recommendations, based on this evidence base, for the evaluation and management of mouse allergy in the pediatric population. PMID:23912589

Matsui, Elizabeth C.

2013-01-01

290

Identification of rodent carcinogens by an expert system  

SciTech Connect

CASE, an artificial intelligence method for identifying structural determinants responsible for biological activity was applied to the U.S. National Toxicology Program (NTP) cancer bioassay results. CASE identified structures which were significantly associated with rodent carcinogenicity. On the basis of these structural determinants CASE exhibited a sensitivity of 0.98 and a specificity of 1.00. CASE showed a similarly remarkable performance in predicting the carcinogenicity, or lack thereof, of chemicals not in the NTP data base. A comparison between the activating structures (biophores) responsible for mutagenicity in Salmonella and rodent carcinogenicity showed a significant overlap, verifying that there are structural commonalities between the two phenomena. CASE also identified biophores significantly associated with the activity of non-genotoxic carcinogens, thereby suggesting the unexpected possibility that there is a structural commonality among the chemicals included in this group. A comparison between the biophores responsible for carcinogenicity in mice and rats resulted in the identification of common (universal) biophores. It is suggested that agents which contain universal biophores are more likely to present a risk to human than carcinogens that do not possess such biophores. CASE also permitted the recognition of species-specific carcinogenic biophores. While the former are primarily electrophiles or potential electrophiles, the latter represent non-electrophilic structures.

Rosenkranz, H.S.; Klopman, G. (Case Western Reserve Univ., Cleveland, OH (USA))

1990-01-01

291

Prairie Rattlesnakes (Crotalus viridis) Respond to Rodent Blood with Chemosensory Searching  

Microsoft Academic Search

In Experiment I, homogenized rodent tissue was applied to the lips of prairie rattlesnakes (Crotalus viridis). This treatment produced elevated rates of tongue flicking compared to controls that received water, but the elevations seen following stimulation with homogenate were not as large as those seen after snakes struck prey. In Experiment II, water, rodent blood, and integumentary cues were applied

David Chiszar; Grant Hobika; Hobart M. Smith

1993-01-01

292

Diffusion MRI of Rodent Glioma at 21T National High Magnetic Field Laboratory  

E-print Network

Diffusion MRI of Rodent Glioma at 21T National High Magnetic Field Laboratory NMR Spectroscopy to understand and further develop surrogate MRI biomarkers of tumor therapy. Diffusion map of rat glioma before of therapy up to ~1.7* 103 mm2/s. Tumor Tumor #12;Sodium MRI of Rodent Glioma at 21T National High Magnetic

Weston, Ken

293

Patawa Virus, a New Arenavirus Hosted by Forest Rodents in French Guiana.  

PubMed

Molecular screening of rodents from French Guiana has detected a new arenavirus, named "Patawa," in two Oecomys species (Muridae, Sigmodontinae). Further investigations are needed to better understand the circulation of this virus in rodent and human populations and its public health impact. PMID:25217336

Lavergne, Anne; de Thoisy, Benoit; Donato, Damien; Guidez, Amandine; Matheus, Séverine; Catzeflis, François; Lacoste, Vincent

2014-09-13

294

STUDY OF THE CHEMICAL AND BEHAVIORAL TOXICOLOGY OF SUBSTITUTE CHEMICALS IN MICROTINE RODENTS  

EPA Science Inventory

Acute oral LD50 and 30-day dietary subacute LC50 studies of 10 selected pesticides were evaluated in microtine rodents. As a means to developing new animal model systems, four species of microtine rodents including Microtus ochrogaster (MO), Microtus canicaudus (MC), Microtus pen...

295

By Hook or by Crook? Morphometry, Competition and Cooperation in Rodent Sperm  

E-print Network

By Hook or by Crook? Morphometry, Competition and Cooperation in Rodent Sperm Simone Immler1 of most murid rodents are characterised by an apical hook of the sperm head that varies markedly in extent across species. In the European woodmouse Apodemus sylvaticus (Muridae), the highly reflected apical hook

Nachman, Michael

296

South America's earliest rodent and recognition of a new interval of mammalian evolution  

Microsoft Academic Search

THE mid-Cenozoic immigration of rodents and primates to South America (when it was widely isolated by oceans) represents a pre-eminent problem in the biogeographical history of placental mammals. The unexpected discovery of South America's earliest rodent in the central Chilean Andes provides information critical to resolving the source area and primitive morphology of South American caviomorphs, suggesting an African origin

André R. Wyss; John J. Flynn; Mark A. Norell; Carl C. Swisher; Reynaldo Charrier; Michael J. Novacek; Malcolm C. McKenna

1993-01-01

297

Estimation of Wildlife Hazard Levels Using Interspecies Correlation Models and Standard Laboratory Rodent Toxicity Data  

Microsoft Academic Search

Toxicity data from laboratory rodents are widely available and frequently used in human health assessments as animal model data. This study explores the possibility of using single rodent acute toxicity values to predict chemical toxicity to a diversity of wildlife species and estimate hazard levels from modeled species sensitivity distributions (SSD). Interspecies correlation estimation (ICE) models predict toxicity values for

Jill A. Awkerman; Sandy Raimondo; Mace G. Barron

2009-01-01

298

Effectiveness of six species of rodents as dispersers of singleleaf piñon pine ( Pinus monophylla )  

Microsoft Academic Search

The effectiveness of six species of rodents as dispersers of singleleaf piñon pine (Pinus monophylla) was investigated in field enclosures. The rodent species were Panamint kangaroo rat (Dipodomys panamintinus), Great Basin pocket mouse (Perognathus parvus), pinyon mouse (Peromyscus truei), deer mouse (Peromyscus maniculatus), least chipmunk (Tamias minimus), and white-tailed antelope ground squirrel (Ammospermophilus leucurus). Five measures of seed harvesting and

Jennifer L. Hollander; Stephen B. Vander Wall

2004-01-01

299

Competitive release in microhabitat use among coexisting desert rodents: a natural experiment  

Microsoft Academic Search

Competitive release among desert rodents on sand dunes of differing species richness was examined in the Great Basin and Mohave Deserts, USA. Expansions in microhabitat use were exhibited by the kangaroo rats Dipodomys ordii and D. merriami (granivorous heteromyid rodents, weighing 49 and 42 g, respectively) as the number of coexisting heteromyid species decreased geographically. Perognathus longimembris, the only common

Eric Larsen

1986-01-01

300

Rodent repellent studies. IV. Preparation and properties of trinitrobenzene-aryl amine complexes  

USGS Publications Warehouse

Data are presented on methods of preparation, chemical arid physical characteristics, toxicity, and repellency to rodents of complexes of symmetrical trinitrohenzene with various aromatic amines: When applied in suitable carriers or incorporated in plastic .films, members of this series ofmaterials were shown to offer significant increases in time required by wild rodents to damage common packaging materials.

DeWitt, J.B.; Bellack, E.; Welch, J.F.

1953-01-01

301

Diversity of gastrointestinal helminths among murid rodents from northern and northeastern Thailand.  

PubMed

The presence of gastrointestinal helminths (GI helminths) was investigated among 725 murid rodents, trapped in various habitats of Nan, Loei and Buri Ram Provinces, Thailand. The study revealed 17 species of rodents infected with 21 species or taxonomic groups of parasites (3 trematodes, 3 cestodes, 14 nematodes and 1 acanthocephalan). The overall prevalence of infection was 57.7% (418/725). Of the gastrointestinal (GI) helminths, the dominant parasitic group was members of the family Trichostrongylidae (24.3%), followed by the cestodes Raillietina sp (17.1%) and Hymenolepis diminuta (8.6%) and the nematode Syphacia muris (8.6%). The GI helminthic infection rates were highest in Mus caroli (81.8%), Mus cervicolor (76.5%), Leopoldamys edwardsi (75.0%), Bandicota indica (71.5%) and Bandicota savilei (71.4%). Highest rodent species richness (RSR) and helminth species richness (HSR) rates were found in Loei, followed by Nan and Buri Ram. The helminth prevalence rate was higher in rodents from Nan, followed by rodents from Loei and Buri Ram. Rodents from irrigated fields had the highest infection rates followed by rodents from upland or dry agricultural areas, forests and domestic habitats. Raillietina sp, Rodentolepis nana (syn. Hymenolepis nana), Hymenolepis diminuta, Moniliformis moniliformis and Cyclodontostomum purvisi, considered zoonotic parasites, were mainly found in rodents from domestic habitats and lowland irrigated fields. PMID:23082550

Chaisiri, Kittipong; Chaeychomsri, Win; Siruntawineti, Jindawan; Ribas, Alexis; Herbreteau, Vincent; Morand, Serge

2012-01-01

302

Keystone rodent interactions: prairie dogs and kangaroo rats structure the biotic composition of a desertified grassland  

E-print Network

Keystone rodent interactions: prairie dogs and kangaroo rats structure the biotic composition. Keystone rodent interactions: prairie dogs and kangaroo rats structure the biotic composition the geographic distributions of black-tailed prairie dogs Cynomys ludovicianus and banner-tailed kangaroo rats

Davidson, Ana

303

Anti-erosion stone bunds influence rodent dynamics and crop damage in Ethiopian highlands  

NASA Astrophysics Data System (ADS)

In areas of subsistence agriculture, a variety of soil conservation methods have been implemented in the last few decades to improve crop yields, however these can have unintended consequences such as providing habitat for rodent pests. We studied rodent population dynamics and estimated crop damage in high and low stone bund density fields for four cropping seasons in Tigray highlands, northern Ethiopia. Stone bunds are physical structures for soil and water conservation, and potentially habitat for rodents. We used a general model to relate the proportion of crop damage to rodent abundance, stone bund density and crop stages. We found a positive correlation between rodent abundance and crop damage, and significant variation in rodent abundance and crop damage between high and low stone bund density fields. Furthermore, crop damage also varied significantly between crop stages. We concluded that Mastomys awashensis and Arvicanthis dembeensis were the two most important crop pests in the highlands causing significant damage. Fields with high stone bund density (~10 m average distance apart) harbor more rodents and endure a significantly higher proportion of crop damage compared to fields with lower stone bund density (~15 m average distance apart). The fact that rodent abundances peaked during the reproductive stage of the crop and around harvest implies the need for management intervention before these crop stages are attained.

Meheretu, Yonas; Welegerima, Kiros; Teferi, Mekonen; Yirga, Gidey; Haile, Mitiku; Sluydts, Vincent; Bauer, Hans; Nyssen, Jan; Deckers, Jozef; Leirs, Herwig

2014-05-01

304

Teasing Apart the Effects of Seed Size and Energy Content on Rodent Scatter-Hoarding Behavior  

PubMed Central

Scatter-hoarding rodents are known to play a crucial role in the seed dispersal of many plant species. Numerous studies have indicated that both seed size and the energy content of seeds can affect rodent foraging behavior. However, seed size is usually associated with energy content per seed, making it difficult to isolate how seed size and energy affect rodent foraging preferences. This study used 99 treatments of artificial seeds (11 seed sizes×9 levels of energy content) to tease apart the effect of seed size and energy content on rodent seed-caching behavior. Both seed traits showed significant effects, but their details depended on the stage of the rodent foraging process. Seeds with higher energy content were harvested more rapidly while seed size only had a modest effect on harvest rate. However, after harvesting, seed size showed a much stronger effect on rodent foraging behavior. Rodents’ choice of which seeds to remove and cache, as well as seed dispersal distance, seemed to reflect an optimal seed size. Our findings could be adapted in future studies to gain a better understanding of scatter-hoarding rodent foraging behavior, and the co-evolutionary dynamics between plant seed production and seed dispersers. PMID:25350369

Wang, Bo; Yang, Xiaolan

2014-01-01

305

DEVELOPING A PREDICTIVE SIMULATION MODEL FOR ANTIANDROGEN IMPACTS ON RODENT PROSTATE  

EPA Science Inventory

Developing a predictive simulation model for antiandrogen impacts on rodent prostate HA Barton1, RW Setzer1, LK Potter1,2 1US EPA, ORD, NHEERL, ETD, PKB, Research Triangle Park, NC and 2Curriculum in Toxicology, UNC, Chapel Hill, NC Alterations in rodent prostate wei...

306

Prevalence of SFTSV among Asian House Shrews and Rodents, China, January–August 2013  

PubMed Central

To evaluate the role of small mammals as hosts of severe fever with thrombocytopenia syndrome virus (SFTSV), we tested serum samples from rodents and shrews in China, collected in 2013. SFTSV antibodies and RNA were detected, suggesting that rodents and shrews might be hosts for SFTSV. PMID:25418111

Liu, Jian-Wei; Wen, Hong-Ling; Fang, Li-Zhu; Zhang, Zhen-Tang; He, Shu-Ting; Xue, Zai-Feng; Ma, Dong-Qiang; Zhang, Xiao-Shuang; Wang, Tao; Yu, Hao; Zhang, Yan

2014-01-01

307

THE USE OF CHEMICALS TO CONTROL FIELD RODENTS AND OTHER PREDATORS. AGRICULTURAL CHEMICALS TECHNOLOGY, NUMBER 5.  

ERIC Educational Resources Information Center

THE PURPOSE OF THIS GUIDE IS TO ASSIST TEACHERS IN PREPARING POST-SECONDARY STUDENTS FOR AGRICULTURAL CHEMICAL OCCUPATIONS. IT IS ONE OF A SERIES OF MODULES DEVELOPED BY A NATIONAL TASK FORCE ON THE BASIS OF DATA FROM STATE STUDIES. SECTIONS ARE (1) USE OF CHEMICALS FOR RODENT CONTROL AND ERADICATION, (2) TERMINOLOGY AND COMPUTATIONS, (3) RODENT…

Ohio State Univ., Columbus. Center for Vocational and Technical Education.

308

ACTIVITY OF LM 2219 (DIFETHIALONE), A NEW ANTICOAGULANT RODENTICIDE, IN COMMENSAL RODENTS  

Microsoft Academic Search

Preliminary studies completed on commensal rodents with the new anticoagulant rodenticide difethialone showed very good efficacy, such that 25 ppm baits could be used effectively. New test results presented in this publication confirm the activity as shown under laboratory conditions in choice tests, which represent more severe conditions, as well as its effectiveness against rodents that are resistant and non-resistant

J. C. Lechevin; Richard M. Poche

1988-01-01

309

Kasetsart J. (Nat. Sci.) 43 : 106 -117 (2009) Relationship of Parasites and Pathogens Diversity to Rodents in  

E-print Network

and trypanosomiasis benefit from the proximity of rodents to domesticated animals to jump from one vector to another organisms to humans. Key words: rodents, zoonoses, parasites, toxoplasmosis, trypanosomiasis 1 Department

Paris-Sud XI, Université de

310

75Vol. 5, No. 1, JanuaryFebruary 1999 Emerging Infectious Diseases Hantaviruses, rodent-borne RNA viruses,  

E-print Network

those associated with Peromyscus species rodents), although the nucleotide sequences of many hantaviruses from Genetic Diversity and Distribution of Peromyscus-Borne Hantaviruses in North America Martha C reservoir is the deer mouse (Peromyscus maniculatus). Hantavirus- infected rodents were identified

311

Neglected tropical diseases in Central America and Panama: review of their prevalence, populations at risk and impact on regional development.  

PubMed

A review of the literature since 2009 reveals a staggering health and economic burden resulting from neglected tropical diseases in Panama and the six countries of Central America (referred to collectively here as 'Central America'). Particularly at risk are the 10.2million people in the region who live on less than $2 per day, mostly in Guatemala, Honduras, Nicaragua and El Salvador. Indigenous populations are especially vulnerable to neglected tropical diseases. Currently, more than 8million Central American children require mass drug treatments annually (or more frequently) for their intestinal helminth infections, while vector-borne diseases are widespread. Among the vector-borne parasitic infections, almost 40% of the population is at risk for malaria (mostly Plasmodium vivax infection), more than 800,000 people live with Chagas disease, and up to 39,000 people have cutaneous leishmaniasis. In contrast, an important recent success story is the elimination of onchocerciasis from Central America. Dengue is the leading arbovirus infection with 4-5million people affected annually and hantavirus is an important rodent-borne viral neglected tropical disease. The leading bacterial neglected tropical diseases include leptospirosis and trachoma, for which there are no disease burden estimates. Overall there is an extreme dearth of epidemiological data on neglected tropical diseases based on active surveillance as well as estimates of their economic impact. Limited information to date, however, suggests that neglected tropical diseases are a major hindrance to the region's economic development, in both the most impoverished Central American countries listed above, as well as for Panama and Costa Rica where a substantial (but largely hidden) minority of people live in extreme poverty. PMID:24846528

Hotez, Peter J; Woc-Colburn, Laila; Bottazzi, Maria Elena

2014-08-01

312

Rodents on pig and chicken farms – a potential threat to human and animal health  

PubMed Central

Rodents can cause major problems through spreading various diseases to animals and humans. The two main species of rodents most commonly found on farms around the world are the house mouse (Mus musculus) and the brown rat (Rattus norvegicus). Both species are omnivorous and can breed year-round under favourable conditions. This review describes the occurrence of pathogens in rodents on specialist pig and chicken farms, which are usually closed units with a high level of bio-security. However, wild rodents may be difficult to exclude completely, even from these sites, and can pose a risk of introducing and spreading pathogens. This article reviews current knowledge regarding rodents as a hazard for spreading disease on farms. Most literature available regards zoonotic pathogens, while the literature regarding pathogens that cause disease in farm animals is more limited. PMID:22957130

Backhans, Annette; Fellström, Claes

2012-01-01

313

Next-Generation Sequencing for Rodent Barcoding: Species Identification from Fresh, Degraded and Environmental Samples  

PubMed Central

Rodentia is the most diverse order among mammals, with more than 2,000 species currently described. Most of the time, species assignation is so difficult based on morphological data solely that identifying rodents at the specific level corresponds to a real challenge. In this study, we compared the applicability of 100 bp mini-barcodes from cytochrome b and cytochrome c oxidase 1 genes to enable rodent species identification. Based on GenBank sequence datasets of 115 rodent species, a 136 bp fragment of cytochrome b was selected as the most discriminatory mini-barcode, and rodent universal primers surrounding this fragment were designed. The efficacy of this new molecular tool was assessed on 946 samples including rodent tissues, feces, museum samples and feces/pellets from predators known to ingest rodents. Utilizing next-generation sequencing technologies able to sequence mixes of DNA, 1,140 amplicons were tagged, multiplexed and sequenced together in one single 454 GS-FLX run. Our method was initially validated on a reference sample set including 265 clearly identified rodent tissues, corresponding to 103 different species. Following validation, 85.6% of 555 rodent samples from Europe, Asia and Africa whose species identity was unknown were able to be identified using the BLASTN program and GenBank reference sequences. In addition, our method proved effective even on degraded rodent DNA samples: 91.8% and 75.9% of samples from feces and museum specimens respectively were correctly identified. Finally, we succeeded in determining the diet of 66.7% of the investigated carnivores from their feces and 81.8% of owls from their pellets. Non-rodent species were also identified, suggesting that our method is sensitive enough to investigate complete predator diets. This study demonstrates how this molecular identification method combined with high-throughput sequencing can open new realms of possibilities in achieving fast, accurate and inexpensive species identification. PMID:23144869

Galan, Maxime; Pagès, Marie; Cosson, Jean-François

2012-01-01

314

Ground-based rodent control in a remote Hawaiian rainforest on Maui  

USGS Publications Warehouse

Effective control of introduced mammalian predators is essential to the recovery of native bird species in Hawai'i. Between August 1996 and December 2004, introduced rodents were controlled within three home ranges of the Po'ouli Melamprosops phaeosoma, a critically endangered Hawaiian honeycreeper. Rats were controlled using a combination of ground-based rodenticide (0.005% diphacinone) application and snap traps. Beginning in August 2001, we monitored the effectiveness of these rodent control efforts. Relative abundances of Black Rats Rattus rattus and Polynesian Rats R. exulans were measured in each of five snap-trapping grids seven times over a 35-month period. Rat populations decreased inside of the rodent control areas, but control effectiveness differed between rat species. During the first year of monitoring, target control levels for R. rattus were consistently achieved in only one of the rodent control areas. Control techniques were refined in areas failing to meet targets. Subsequently, we achieved target control levels for R. rattus more consistently in all three rodent control areas. However, relative abundances of R. exulans did not differ between rodent control and reference areas, indicating that our rodent control techniques were insufficient to reduce population levels of this species. These findings signify a need for further improvement of rodent control methods in Hawai'i, especially for Polynesian Rats, and demonstrate the critical importance of periodic monitoring of the response of rodent populations to management. In the future, managers may need to design rodent control operations targeting R. rattus and R. exulans independently to achieve best results.

Malcolm, T.R.; Swinnerton, K.J.; Groombridge, J.J.; Sparklin, B.D.; Brosius, C.N.; Vetter, J.P.; Foster, J.T.

2008-01-01

315

Cell proliferation not associated with carcinogenesis in rodents and humans.  

PubMed Central

Cell proliferation has often been found to be associated with carcinogenesis in rodents and humans at different stages of the multistage carcinogenesis process. The multistage process includes initiation, promotion, and progression phases. At each phase, increasing the normal level of cell turnover of target cells may enhance carcinogenesis. However, we present evidence that normal levels of cell turnover, or increasing the rate of cell turnover at these different stages, do not necessarily lead to enhanced carcinogenesis. In normal tissues, the length of the cell cycle depends on the age of the host and varies from tissue to tissue. Tissues with normal short cell cycles, such as intestine and bone marrow, do not show a high rate of spontaneous tumors in most species. Cells with higher turnover should be more susceptible to carcinogens at the initiation stage of carcinogenesis if cell proliferation per se causes cancer and if these cells or their progeny survive. Cancer in humans is more often associated with specific etiological factors rather than with the natural proliferative rate of specific tissues. For many tissues of humans and rodents, age-related diseases develop in a progressive, irreversible manner. Often, naturally occurring chronic degenerative and inflammatory changes in a tissue (e.g., kidney, liver, heart, reproductive tract) lead to chronic regeneration of the damaged tissue. Yet, cancer is rarely found in these tissues. In rodent carcinogenesis experiments, chronic toxic lesions, accompanied by increases in normal levels of cell turnover, have sometimes been observed in target organs of nongenotoxic carcinogens. More often, however, organ-specific nongenotoxic toxins are not carcinogens. These toxins include compounds toxic for the liver, kidney, and nasal cavity. In 19 inhalation bioassays conducted by the National Toxicology Program, 5/5 nasal carcinogens and 12/14 nasal noncarcinogens caused nasal lesions usually associated with chronic cell proliferation. Although cell proliferation may contribute to multistage carcinogenesis, cell proliferation is not necessarily a tumor promoter or cocarcinogen. Images FIGURE 2. FIGURE 4. FIGURE 5. FIGURE 6. A FIGURE 6. B FIGURE 7. PMID:8013399

Ward, J M; Uno, H; Kurata, Y; Weghorst, C M; Jang, J J

1993-01-01

316

Changes in the abundance of birds in relation to small rodent density and predation rate in Finnish Lapland  

Microsoft Academic Search

The relationships between breeding bird numbers, small rodent density and predation on birds' nests were studied in Finnish Lapland in 1966–87. The cycle length of small rodents was 4–¸5 years. There was a close association between small rodents and the number of Redstart pairs breeding in accessible sites in mountain birch forest, but not with Pied Flycatcher pairs breeding in

A. Järvinen

1990-01-01

317

Evaluation on the effectiveness of actions for controlling infestation by rodents in Campo Limpo region, São Paulo Municipality, Brazil  

Microsoft Academic Search

Rodents are responsible for the transmission of more than 60 diseases both to human beings and to domestic animals. The increase in rodent infestation in a given area brings several health problems to the nearby population. Thus, when infestation increases, it is time to take intervention measures. Although many countries have implemented programs aimed at controlling rodent infestation, literature on

Eduardo de Masi; Pedro José Vilaça; Maria Tereza Pepe Razzolini

2009-01-01

318

University of the humid tropics  

NASA Astrophysics Data System (ADS)

The creation of a foundation called the University of the Humid Tropics (UNITROP) was announced by Brazilian atmospheric scientist Luiz Carlos Molion at the AGU Chapman Conference on Global Biomass Burning, held March 23 in Williamsburg, Va. The headquarters for UNITROP is in Manaus, Amazonia, Brazil. UNITROP is not a university in a narrow sense, but an institution created and run by scientists with the purpose of understanding Amazonia and developing it socio-economically in harmony with its environment, Molion said.The scientific objectives of UNITROP are: Research: Promote, organize and fund researchers and research in Amazonia, encompassing all branches of science, from social and aboriginal issues to biogeophysicalchemical processes, and leading to an integrated understanding of the tropical forest environment and its transformation.

319

Polytropic process and tropical Cyclones  

E-print Network

We show a parallelism between the expansion and compression of the atmosphere in the secondary cycle of a tropical cyclone with the fast expansion and compression of wet air in a bottle. We present a simple model in order to understand how the system (cyclone) draws energy from the air humidity. In particular we suggest that the upward (downward) expansion (compression) of the warm (cold) moist (dry) air follows a polytropic process, $PV^\\beta$= constant. We show both experimentally and analytically that $\\beta$ depends on the initial vapor pressure in the air. We propose that the adiabatic stages in the Carnot-cycle model for the tropical cyclone be replaced by two polytropic stages. These polytropic processes can explain how the wind wins energy and how the rain and the dry bands are produced inside the storm.

Romanelli, Alejandro; Rodríguez, Juan

2013-01-01

320

Tropical Mesoscale and Local Circulations  

NSDL National Science Digital Library

This interactive module is part of an online university-level tropical synoptic meteorology course, which helps international meteorologists meet basic instructional requirements. In the module, we discuss: Mesoscale, thermally-forced circulations (i.e. land-sea breeze and mountain-valley breeze), including How they are formed and their diurnal cycle Factors that modify thermally forced circulations The weather associated with thermally forced circulations, particularly convection and other significant weather Interactions of mesoscale, thermally forced circulations with other atmospheric phenomena, including Intersection of mesoscale circulations and of mesoscale circulations with convective outflow boundaries Thermally forced circulation interactions with monsoonal and trade wind flows The impact of thermally forced and interacting circulations at various scales on the diurnal cycle of precipitation in the tropics, and A case example from the Lake Victoria basin, showing complex thermally forced circulations, outflow boundaries, and synoptic scale flow.

Comet

2012-11-27

321

Ecotoxicology of tropical marine ecosystems  

SciTech Connect

The negative effects of chemical contaminants on tropical marine ecosystems are of increasing concern as human populations expand adjacent to these communities. Watershed streams and ground water carry a variety of chemicals from agricultural, industrial, and domestic activities, while winds and currents transport pollutants from atmospheric and oceanic sources to these coastal ecosystems. The implications of the limited information available on impacts of chemical stressors on mangrove forests, seagrass meadows, and coral reefs are discussed in the context of ecosystem management and ecological risk assessment. Three classes of pollutants have received attention: heavy metals, petroleum, and synthetic organics. Heavy metals have been detected in all three ecosystems, causing physiological stress, reduced reproductive success, and outright mortality in associated invertebrates and fishes. Oil spills have been responsible for the destruction of entire coastal shallow-water communities, with recovery requiring years. Herbicides are particularly detrimental to mangroves and seagrasses and adversely affect the animal-algal symbioses in corals. Pesticides interfere with chemical cues responsible for key biological processes, including reproduction and recruitment of a variety of organisms. Information is lacking with regard to long-term recovery, indicator species, and biomarkers for tropical communities. Critical areas that are beginning to be addressed include the development of appropriate benchmarks for risk assessment, baseline monitoring criteria, and effective management strategies to protect tropical marine ecosystems in the face of mounting anthropogenic disturbance.

Peters, E.C. [Tetra Tech, Inc., Fairfax, VA (United States); Gassman, N.J.; Firman, J.C. [Univ. of Miami, FL (United States). Rosenstiel School of Marine and Atmospheric Science; Richmond, R.H. [Univ. of Guam, Mangilao (Guam). Marine Lab.; Power, E.A. [EVS Environment Consultants, Ltd., North Vancouver, British Columbia (Canada)

1997-01-01

322

Wheel-running behavior in 12 species of muroid rodents.  

PubMed

The objective of this research was to describe the levels and periodicity of wheel running in 12 species of muroid rodents in order that comparisons could be made among different measures of activity in a variety of species. Six males from each species (Peromyscus polionotus, P. eremicus, P. leucopus, P. maniculatus, P. gossypinus, Microtus pennysylvanicus, M. montanus, M. canicaudus, M. ochrogaster, Calomys callos us, Onychomys leucogaster, and Mus musculus) were tested in running wheels for 14 days, with the amount of running recorded hourly. There were significant species differences in amount of wheel running, with Peromyscus generally running more than Microtus. All species displayed marked nocturnality. Thus, Peromyscus display consistent nocturnality both across species, and for various behavioral patterns measured using a variety of methods. By contrast, Microtus display a nocturnal pattern of wheel running, but not of eating, drinking, and various other behavioral patterns. These differences appear to reflect adaptations related to habit and diet. PMID:24925276

Dewsbury, D A

1980-09-01

323

Experimental Evidence for Reduced Rodent Diversity Causing Increased Hantavirus Prevalence  

PubMed Central

Emerging and re-emerging infectious diseases have become a major global environmental problem with important public health, economic, and political consequences. The etiologic agents of most emerging infectious diseases are zoonotic, and anthropogenic environmental changes that affect wildlife communities are increasingly implicated in disease emergence and spread. Although increased disease incidence has been correlated with biodiversity loss for several zoonoses, experimental tests in these systems are lacking. We manipulated small-mammal biodiversity by removing non-reservoir species in replicated field plots in Panama, where zoonotic hantaviruses are endemic. Both infection prevalence of hantaviruses in wild reservoir (rodent) populations and reservoir population density increased where small-mammal species diversity was reduced. Regardless of other variables that affect the prevalence of directly transmitted infections in natural communities, high biodiversity is important in reducing transmission of zoonotic pathogens among wildlife hosts. Our results have wide applications in both conservation biology and infectious disease management. PMID:19421313

Suzán, Gerardo; Marcé, Erika; Giermakowski, J. Tomasz; Mills, James N.; Ceballos, Gerardo; Ostfeld, Richard S.; Armién, Blas; Pascale, Juan M.; Yates, Terry L.

2009-01-01

324

Amorphous intergranular phases control the properties of rodent tooth enamel.  

PubMed

Dental enamel, a hierarchical material composed primarily of hydroxylapatite nanowires, is susceptible to degradation by plaque biofilm-derived acids. The solubility of enamel strongly depends on the presence of Mg(2+), F(-), and CO3 (2-). However, determining the distribution of these minor ions is challenging. We show-using atom probe tomography, x-ray absorption spectroscopy, and correlative techniques-that in unpigmented rodent enamel, Mg(2+) is predominantly present at grain boundaries as an intergranular phase of Mg-substituted amorphous calcium phosphate (Mg-ACP). In the pigmented enamel, a mixture of ferrihydrite and amorphous iron-calcium phosphate replaces the more soluble Mg-ACP, rendering it both harder and more resistant to acid attack. These results demonstrate the presence of enduring amorphous phases with a dramatic influence on the physical and chemical properties of the mature mineralized tissue. PMID:25678658

Gordon, Lyle M; Cohen, Michael J; MacRenaris, Keith W; Pasteris, Jill D; Seda, Takele; Joester, Derk

2015-02-13

325

Coding odor identity and odor value in awake rodents  

PubMed Central

In the last decade, drastic changes in the understanding of the role of the olfactory bulb and piriform cortex in odor detection have taken place through awake behaving recording in rodents. It is clear that odor responses in mitral and granule cells are strikingly different in the olfactory bulb of anesthetized vs. awake animals. In addition, sniff recording has evidenced that mitral cell responses to odors during the sniff can convey information on the odor identity and sniff phase. Moreover, we review studies that show that the mitral cell conveys not only information on odor identity but also on whether the odor is rewarded or not (odor value). Finally, we discuss how the substantial increase in awake behaving recording raises questions for future studies. PMID:24767484

Nuñez-Parra, Alexia; Li, Anan; Restrepo, Diego

2014-01-01

326

Hippocampal lipoprotein lipase regulates energy balance in rodents?  

PubMed Central

Brain lipid sensing is necessary to regulate energy balance. Lipoprotein lipase (LPL) may play a role in this process. We tested if hippocampal LPL regulated energy homeostasis in rodents by specifically attenuating LPL activity in the hippocampus of rats and mice, either by infusing a pharmacological inhibitor (tyloxapol), or using a genetic approach (adeno-associated virus expressing Cre-GFP injected into Lpllox/lox mice). Decreased LPL activity by either method led to increased body weight gain due to decreased locomotor activity and energy expenditure, concomitant with increased parasympathetic tone (unchanged food intake). Decreased LPL activity in both models was associated with increased de novo ceramide synthesis and neurogenesis in the hippocampus, while intrahippocampal infusion of de novo ceramide synthesis inhibitor myriocin completely prevented body weight gain. We conclude that hippocampal lipid sensing might represent a core mechanism for energy homeostasis regulation through de novo ceramide synthesis. PMID:24634821

Picard, Alexandre; Rouch, Claude; Kassis, Nadim; Moullé, Valentine S.; Croizier, Sophie; Denis, Raphaël G.; Castel, Julien; Coant, Nicolas; Davis, Kathryn; Clegg, Deborah J.; Benoit, Stephen C.; Prévot, Vincent; Bouret, Sébastien; Luquet, Serge; Le Stunff, Hervé; Cruciani-Guglielmacci, Céline; Magnan, Christophe

2013-01-01

327

[Structural characteristics of certain Rodents spines (Rodentia: Myomorpha, Hystricomorpha)].  

PubMed

The architectonics of spines and hair was studied in Neacomys spinosus, Arvicanthis somalicus, Leopoldamys sabanus, L. edwardsi, Maxomys moi, M. surifer, Niviventer fulvescens, N. confucianus, N. cremoriventer, Acomys cahirinus, A. somalica, Hystrix indica, H. cristata, Atherurus macrourus, Erethizon dorsatum, Proechimys steerei, and Lonchotrix emiliae. The presence of a dorsal longitudinal furrow covered by a modified cuticle is a common structural feature of spines in all studied species except E. dorsatum, H. indica, and the frontal surface of the mosaic (scales located side by side) and terrace cuticle (steps between scales) varies in different species from smooth to rib-folded. A terminology has been proposed to describe the main structures of spine and hair. The adaptive significance of the spine architectonics in rodents is discussed. PMID:11525125

Chernova, O F; Kuznetsov, G V

2001-01-01

328

Toward a rodent model of the Iowa gambling task.  

PubMed

The Iowa gambling task in humans is, in principle, suited for the study of the long-term efficiency of behavior in a biologically relevant context. Key features of this task are uncertainty of outcomes and a conflict between the immediate and the long-term payoff options. Animal models allow us to study the underlying neurobiology of decision-making processes and the long-term efficiency of behavior in more detail and at a greater depth than is possible in humans. Therefore, we set out to develop a model of this task in rodents, using the task's key features. In this article, we describe the results of the first series of experiments with rats and mice. The data thus far suggest that mice and rats behave in a way similar to humans; that is, they tend to choose the option with the best long-term payoff more often as the test progresses. PMID:17186757

van den Bos, Ruud; Lasthuis, Wilma; den Heijer, Esther; van der Harst, Johanneke; Spruijt, Berry

2006-08-01

329

Identification of novel anelloviruses with broad diversity in UK rodents.  

PubMed

Anelloviruses are a family of small circular ssDNA viruses with a vast genetic diversity. Human infections with the prototype anellovirus, torque teno virus (TTV), are ubiquitous and related viruses have been described in a number of other mammalian hosts. Despite over 15 years of investigation, there is still little known about the pathogenesis and possible disease associations of anellovirus infections, arising in part due to the lack of a robust cell culture system for viral replication or tractable small-animal model. We report the identification of diverse anelloviruses in several species of wild rodents. The viruses are highly prevalent in wood mice (Apodemus sylvaticus) and field voles (Microtus agrestis), detectable at a low frequency in bank voles (Myodes glareolus), but absent from house mice (Mus musculus). The viruses identified have a genomic organization consistent with other anelloviruses, but form two clear phylogenetic groups that are as distinct from each other as from defined genera. PMID:24744300

Nishiyama, Shoko; Dutia, Bernadette M; Stewart, James P; Meredith, Anna L; Shaw, Darren J; Simmonds, Peter; Sharp, Colin P

2014-07-01

330

Photoperiodic control of circadian activity rhythms in diurnal rodents  

NASA Astrophysics Data System (ADS)

The responses of red squirrels (Tamiasciurus hudsonicus) and eastern chipmunks (Tamias striatus) to complete and skeleton light-dark (LD) cycles were compared. The skeletons, comprised of two 1-h pulses of light per day, effectively simulated the complete photoperiods in the squirrels, but not the chipmunks. Skeleton photoperiods greater than 12-h caused the chipmunks to shift activity from the longer to the shorter of the two intervals between the pulses. To interpret the mechanism of phase control, squirrels and chipmunks were kept in continuous darkness and exposed to 1-h light pulses every 10 days. The time-course of entrainment was also quantified. Both techniques produced light-response curves. The data suggest that the parametric and non-parametric contributions to entrainment are different in these two rodent species.

Kramm, K. R.; Kramm, Deborah A.

1980-03-01

331

Primary Dissociated Midbrain Dopamine Cell Cultures from Rodent Neonates  

PubMed Central

The ability to create primary cell cultures of dopamine neurons allows for the study of the presynaptic characteristics of dopamine neurons in isolation from systemic input from elsewhere in the brain. In our lab, we use these neurons to assess dopamine release kinetics using carbon fiber amperometry, as well as expression levels of dopamine related genes and proteins using quantitative PCR and immunocytochemistry. In this video, we show you how we generate these cultures from rodent neonates. The process involves several steps, including the plating of cortical glial astrocytes, the conditioning of neuronal cell culture media by the glial substrate, the dissection of the midbrain in neonates, the digestion, extraction and plating of dopamine neurons and the addition of neurotrophic factors to ensure cell survival. The applications suitable for such a preparation include electrophysiology, immunocytochemistry, quantitative PCR, video microscopy (i.e., of real-time vesicular fusion with the plasma membrane), cell viability assays and other toxicological screens. PMID:19066533

Frank, Lauren E.; Caldera-Siu, Angela D.; Pothos, Emmanuel N.

2008-01-01

332

Pulmonary Toxicity Studies of Lunar Dusts in Rodents  

NASA Technical Reports Server (NTRS)

NASA will build an outpost on the lunar surface for long-duration human habitation and research. The surface of the Moon is covered by a layer of fine, reactive dust, and the living quarters in the lunar outpost are expected to be contaminated by lunar dust. Because the toxicity of lunar dust is not known, NASA has tasked its toxicology laboratory to evaluate the risk of exposure to the dust and to establish safe exposure limits for astronauts working in the lunar habitat. Studies of the pulmonary toxicity of a dust are generally done first in rodents by intratracheal/intrapharyngeal instillation. This toxicity screening test is then followed by an inhalation study, which requires much more of the test dust and is labor intensive. Preliminary results obtained by examining lung lavage fluid from dust-treated mice show that lunar dust was somewhat toxic (more toxic than TiO2, but less than quartz dust). More extensive studies are in progress to further examine lung lavage fluid for biomarkers of toxicity and lung tissues for histopathological lesions in rodents exposed to aged and activated (ground) lunar dust samples. In these studies, reference dusts (TiO2 and quartz) of known toxicities and have industrial exposure limits will be studied in parallel so the relative toxicity of lunar dust can be determined. The results from the instillation studies will be useful for choosing exposure concentrations for the animal inhalation study. The animal inhalation exposure will be conducted with lunar dust simulant prior to the study with the lunar dust. The experiment with the simulate will ensure that the study techniques used with actual lunar dust will be successful. The results of instillation and inhalation studies will reveal the toxicological risk of exposures and are essential for setting exposure limits on lunar dust for astronauts living in the lunar habitat.

Lam, Chiu-wing; James, John T.

2009-01-01

333

DNA Barcoding of Sigmodontine Rodents: Identifying Wildlife Reservoirs of Zoonoses  

PubMed Central

Species identification through DNA barcoding is a tool to be added to taxonomic procedures, once it has been validated. Applying barcoding techniques in public health would aid in the identification and correct delimitation of the distribution of rodents from the subfamily Sigmodontinae. These rodents are reservoirs of etiological agents of zoonoses including arenaviruses, hantaviruses, Chagas disease and leishmaniasis. In this study we compared distance-based and probabilistic phylogenetic inference methods to evaluate the performance of cytochrome c oxidase subunit I (COI) in sigmodontine identification. A total of 130 sequences from 21 field-trapped species (13 genera), mainly from southern Brazil, were generated and analyzed, together with 58 GenBank sequences (24 species; 10 genera). Preliminary analysis revealed a 9.5% rate of misidentifications in the field, mainly of juveniles, which were reclassified after examination of external morphological characters and chromosome numbers. Distance and model-based methods of tree reconstruction retrieved similar topologies and monophyly for most species. Kernel density estimation of the distance distribution showed a clear barcoding gap with overlapping of intraspecific and interspecific densities < 1% and 21 species with mean intraspecific distance < 2%. Five species that are reservoirs of hantaviruses could be identified through DNA barcodes. Additionally, we provide information for the description of a putative new species, as well as the first COI sequence of the recently described genus Drymoreomys. The data also indicated an expansion of the distribution of Calomys tener. We emphasize that DNA barcoding should be used in combination with other taxonomic and systematic procedures in an integrative framework and based on properly identified museum collections, to improve identification procedures, especially in epidemiological surveillance and ecological assessments. PMID:24244670

Müller, Lívia; Gonçalves, Gislene L.; Cordeiro-Estrela, Pedro; Marinho, Jorge R.; Althoff, Sérgio L.; Testoni, André. F.; González, Enrique M.; Freitas, Thales R. O.

2013-01-01

334

Arctic Small Rodents Have Diverse Diets and Flexible Food Selection  

PubMed Central

The ecology of small rodent food selection is poorly understood, as mammalian herbivore food selection theory has mainly been developed by studying ungulates. Especially, the effect of food availability on food selection in natural habitats where a range of food items are available is unknown. We studied diets and selectivity of grey-sided voles (Myodes rufocanus) and tundra voles (Microtus oeconomus), key herbivores in European tundra ecosystems, using DNA metabarcoding, a novel method enabling taxonomically detailed diet studies. In order to cover the range of food availabilities present in the wild, we employed a large-scale study design for sampling data on food availability and vole diets. Both vole species had ingested a range of plant species and selected particularly forbs and grasses. Grey-sided voles also selected ericoid shrubs and tundra voles willows. Availability of a food item rarely affected its utilization directly, although seasonal changes of diets and selection suggest that these are positively correlated with availability. Moreover, diets and selectivity were affected by availability of alternative food items. These results show that the focal sub-arctic voles have diverse diets and flexible food preferences and rarely compensate low availability of a food item with increased searching effort. Diet diversity itself is likely to be an important trait and has previously been underrated owing to methodological constraints. We suggest that the roles of alternative food item availability and search time limitations for small rodent feeding ecology should be investigated. Nomenclature Annotated Checklist of the Panarctic Flora (PAF), Vascular plants. Available at: http://nhm2.uio.no/paf/, accessed 15.6.2012. PMID:23826371

Soininen, Eeva M.; Ravolainen, Virve T.; Bråthen, Kari Anne; Yoccoz, Nigel G.; Gielly, Ludovic; Ims, Rolf A.

2013-01-01

335

Modelling cognitive affective biases in major depressive disorder using rodents  

PubMed Central

Major depressive disorder (MDD) affects more than 10% of the population, although our understanding of the underlying aetiology of the disease and how antidepressant drugs act to remediate symptoms is limited. Major obstacles include the lack of availability of good animal models that replicate aspects of the phenotype and tests to assay depression-like behaviour in non-human species. To date, research in rodents has been dominated by two types of assays designed to test for depression-like behaviour: behavioural despair tests, such as the forced swim test, and measures of anhedonia, such as the sucrose preference test. These tests have shown relatively good predictive validity in terms of antidepressant efficacy, but have limited translational validity. Recent developments in clinical research have revealed that cognitive affective biases (CABs) are a key feature of MDD. Through the development of neuropsychological tests to provide objective measures of CAB in humans, we have the opportunity to use ‘reverse translation’ to develop and evaluate whether similar methods are suitable for research into MDD using animals. The first example of this approach was reported in 2004 where rodents in a putative negative affective state were shown to exhibit pessimistic choices in a judgement bias task. Subsequent work in both judgement bias tests and a novel affective bias task suggest that these types of assay may provide translational methods for studying MDD using animals. This review considers recent work in this area and the pharmacological and translational validity of these new animal models of CABs. Linked Articles This article is part of a themed section on Animal Models in Psychiatry Research. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-20 PMID:24467454

Hales, Claire A; Stuart, Sarah A; Anderson, Michael H; Robinson, Emma S J

2014-01-01

336

Dietary cholesterol enhances torpor in a rodent hibernator.  

PubMed

Dietary cholesterol can affect both body lipid composition and steroid hormone concentration. We investigated whether a diet rich in cholesterol influences torpor patterns of hibernating chipmunks (Tamias amoenus) and, if so, whether these changes are better explained by diet-induced changes in body lipid composition or the concentration of testosterone, which at high levels inhibits torpor. Two groups of chipmunks were maintained either on a cholesterol diet (rodent chow containing 10% cholesterol) or a control diet (rodent chow) during pre-hibernation fattening and throughout the hibernation season. Torpid chipmunks on the cholesterol diet had significantly lower minimum body temperatures (-0.2 +/- 0.2 vs -0.6 +/- 0.2 degree C), lower metabolic rates (0.029 +/- 0.002 ml O2 g-1 h-1 vs 0.035 +/- 0.001 ml O2 g-1 h-1), and longer torpor bouts at -1 degree C (6.8 +/- 0.5 vs 4.1 +/- 1.0 days) than chipmunks on the control diet. Dietary cholesterol resulted in a significant increase in blood plasma cholesterol (sevenfold), liver cholesterol content (6.9-fold) and liver triglyceride content (3.5-fold) in comparison to controls. In contrast, dietary cholesterol had no detectable effect on the concentration of plasma testosterone, which was very low in both groups. Since torpor was deeper and longer in animals on the cholesterol diet our study suggests that torpor patterns of chipmunks were either directly affected by the dietary cholesterol or via changes in body lipid composition. PMID:9286090

Geiser, F; Kenagy, G J; Wingfield, J C

1997-08-01

337

Tropical forest preservation using economic incentives  

SciTech Connect

The authors address the problem of deforestation of the tropical forests in terms of economic factors. They outline the global effects, such as hydrological and climatological changes, that apparently small scale deforestation has, when the forest is destroyed in many different places. The authors suggest that industrialized nations should offer economic incentives for tropical nations to save their forests, since all the world will suffer the effects of tropical deforestation.

Katzman, M.T. (Oak Ridge National Lab., TN (USA)); Cale, W.G. Jr. (Univ. of Pennsylvania, Indiana (USA))

1990-12-01

338

Microbial Degradation of Pesticides in Tropical Soils  

Microsoft Academic Search

\\u000a Although their use is at least as essential in tropical as in temperate zones, pesticides remain little studied as regards\\u000a their fate and microbial degradation in tropical soils. To contribute to closing this gap, this review examines to what extent\\u000a results from studies on pesticide microbial degradation in temperate zones can be extrapolated to the tropics. It is concluded\\u000a that

Ziv Arbeli; Cilia L. Fuentes

339

Ecosystem engineering by a colonial mammal: how prairie dogs structure rodent communities.  

PubMed

As ecosystem engineers, prairie dogs (Cynomys spp.) physically alter their environment, but the mechanism by which these alterations affect associated faunal composition is not well known. We examined how rodent and vegetation communities responded to prairie dog colonies and landcover at the Cimarron National Grassland in southwest Kansas, USA. We trapped rodents and measured vegetation structure on and off colonies in 2000 and 2003. We plotted two separate ordinations of trapping grids: one based on rodent counts and a second based on vegetation variables. We regressed three factors on each ordination: (1) colony (on-colony and off-colony), (2) cover (shortgrass and sandsage), and (3) habitat (factorial cross of colony x cover). Rodent communities differed by colony but not cover. Vegetation differed across both gradients. Rodent responses to habitat reflected those of colony and cover, but vegetation was found to differ across cover only in the sandsage prairie. This interaction suggested that rodent composition responded to prairie dog colonies, but independently of vegetation differences. We conclude that burrowing and soil disturbance are more important than vegetation cropping in structuring rodent communities. PMID:19137937

VanNimwegen, Ron E; Kretzer, Justin; Cully, Jack F

2008-12-01

340

INTER-AMERICAN TROPICAL TUNA COMMISSION COMISIN INTERAMERICANA DEL ATN TROPICAL  

E-print Network

INTER-AMERICAN TROPICAL TUNA COMMISSION COMISIÃ?N INTERAMERICANA DEL ATÃ?N TROPICAL 73RD MEETING The Inter-American Tropical Tuna Commission (IATTC): Taking into account the FAO International Plan to evaluate the incidental mortality of seabirds during longline fishing operations for tunas and tuna

341

The ecology of tropical lakes and rivers  

SciTech Connect

This is self-contained text reviewing tropical limnology. It discusses a number of communities in detail, including plankton, benthic regions, and the water margins. It introduces the characteristic types and assemblies of animals and plants from tropical communities. The measurement and relative magnitude of such quantifiable aspects as abundance, biomass, primary production, secondary production, and decomposition are all outlined, drawing together the diverse threads of freshwater ecology over one of the earth's climatic belts. Deals with use and abuse of water in the tropics and looks at problems of diversity and diversification in tropical waters.

Payne, A.I.

1986-01-01

342

Ancient tropical climates warm San Francisco gathering  

SciTech Connect

Climate records preserved in the Greenland ice sheet got a lot of the attention at the fall meeting of the American Geophysical Union (AGU) in San Francisco last month, but ancient tropical records were a rival attraction. In talks scattered in unrelated sessions, researchers reported a possible role for the tropics in driving the last ice age, a link between high latitudes and the tropics that may have redirected human evolution, and a tropical climate periodicity that may fill a gap in the understanding of climate variability.

Kerr, R.A.

1994-01-14

343

Microbial safety of tropical and sub-tropical fruit. in Volume 1 – General Physiology, Quality and Handling of Tropical and Sub-tropical Fruits, Postharvest Biology & Technology of Tropical and Sub-tropical Fruits  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter describes past outbreaks, potential routes of contamination for specific, potential interventions, and operational procedures associated with tropical and sub-tropical fruits. Various pre-harvest sources can result in contamination of fruits; and survival and growth of pathogens on who...

344

Seasonally dry tropical forest mammals: Adaptations and seasonal patterns  

E-print Network

Seasonally dry tropical forests have one of the most extreme climates within tropical ecosystems. Mammals that inhabit tropical dry forests must be capable of dealing with high temperatures, low precipitation in the dry ...

Stoner, Kathryn E.; Timm, Robert M.

2011-01-01

345

The Role of the Tropics in Abrupt Climate Changes  

SciTech Connect

Topics addressed include: abrupt climate changes and ocean circulation in the tropics; what controls the ocean thermal structure in the tropics; a permanent El Niño in paleoclimates; the energetics of the tropical ocean.

Fedorov, Alexey [Yale University] [Yale University

2013-12-07

346

Future economic damage from tropical cyclones: sensitivities to societal and  

E-print Network

Future economic damage from tropical cyclones: sensitivities to societal and climate changes from tropical cyclones under a range of assumptions about societal change, climate change related to tropical cyclones than efforts to modulate the behaviour of storms through greenhouse gas

Colorado at Boulder, University of

347

Camera Trapping: A Contemporary Approach to Monitoring Invasive Rodents in High Conservation Priority Ecosystems  

PubMed Central

Invasive rodent species have established on 80% of the world's islands causing significant damage to island environments. Insular ecosystems support proportionally more biodiversity than comparative mainland areas, highlighting them as critical for global biodiversity conservation. Few techniques currently exist to adequately detect, with high confidence, species that are trap-adverse such as the black rat, Rattus rattus, in high conservation priority areas where multiple non-target species persist. This study investigates the effectiveness of camera trapping for monitoring invasive rodents in high conservation areas, and the influence of habitat features and density of colonial-nesting seabirds on rodent relative activity levels to provide insights into their potential impacts. A total of 276 camera sites were established and left in situ for 8 days. Identified species were recorded in discrete 15 min intervals, referred to as ‘events’. In total, 19 804 events were recorded. From these, 31 species were identified comprising 25 native species and six introduced. Two introduced rodent species were detected: the black rat (90% of sites), and house mouse Mus musculus (56% of sites). Rodent activity of both black rats and house mice were positively associated with the structural density of habitats. Density of seabird burrows was not strongly associated with relative activity levels of rodents, yet rodents were still present in these areas. Camera trapping enabled a large number of rodents to be detected with confidence in site-specific absences and high resolution to quantify relative activity levels. This method enables detection of multiple species simultaneously with low impact (for both target and non-target individuals); an ideal strategy for monitoring trap-adverse invasive rodents in high conservation areas. PMID:24599307

Rendall, Anthony R.; Sutherland, Duncan R.; Cooke, Raylene; White, John

2014-01-01

348

Anti-dementia drugs and hippocampal-dependent memory in rodents  

PubMed Central

Abnormalities in hippocampal structure and function are characteristics of early Alzheimer's disease (AD). Behavioral tests measuring hippocampal-dependent memory in rodents are often used to evaluate novel treatments for AD and other dementias. In this study, we review the effects of drugs marketed for the treatment of AD, such as the acetylcholinesterase inhibitors, donepezil, rivastigmine, galantamine and the N-methyl-d-aspartic acid antagonist, memantine, in rodent models of memory impairment. We also briefly describe the effects of novel treatments for cognitive impairment in rodent models of memory impairment, and discuss issues concerning the selection of the animal model and behavioral tests. Suggestions for future research are offered. PMID:17762506

Yuede, Carla M.; Dong, Hongxin; Csernansky, John G.

2009-01-01

349

Pathology of Rodent Models of Intestinal Cancer: Progress Report and Recommendations  

PubMed Central

In October 2010, a pathology review of rodent models of intestinal neoplasia was held at The Jackson Laboratory. This review complemented 2 other concurrent events: a workshop on methods of modeling colon cancer in rodents and a conference on current issues in murine and human colon cancer. We summarize the results of the pathology review and the committee’s recommendations for tumor nomenclature. A virtual high-resolution image slide box of these models has been developed. This report discusses significant recent developments in rodent modeling of intestinal neoplasia, including the role of stem cells in cancer and the creation of models of metastatic intestinal cancer. PMID:23415801

Washington, Mary Kay; Powell, Anne E.; Sullivan, Ruth; Sundberg, John; Wright, Nicholas; Coffey, Robert J.; Dove, William F.

2013-01-01

350

Vulnerability of Tropical Pacific Fisheries and Aquaculture  

E-print Network

3 Vulnerability of Tropical Pacific Fisheries and Aquaculture to Climate Change Edited by Johann D and Aquaculture to Climate Change Edited by Johann D Bell, Johanna E Johnson and Alistair J Hobday #12;ii of Tropical Pacific Fisheries and Aquaculture to Climate Change 1. Fishery management ­ Oceania. 2. Marine

351

Mesoscale Interactions in Tropical Cyclone Genesis  

Microsoft Academic Search

With the multitude of cloud clusters over tropical oceans, it has been perplexing that so few develop into tropical cyclones. The authors postulate that a major obstacle has been the complexity of scale interactions, particularly those on the mesoscale, which have only recently been observable. While there are well-known climatological requirements, these are by no means sufficient. A major reason

J. Simpson; E. Ritchie; G. J. Holland; J. Halverson; S. Stewart

1997-01-01

352

Carbon Cycling in Tropical and Boreal Forests  

E-print Network

Carbon Cycling in Tropical and Boreal Forests Scott Miller University of California, Irvine #12;Is, Third Assessment Report, 2000 #12;The Global Carbon Budget: Terms we know well 0 1 2 3 4 5 6 7 8 CO2 CO2 Uptake by oceans GigaTonsCarbonperyear The Global Carbon Budget: Terms we kind of know tropical

Goulden, Michael L.

353

TROPICAL MASS EXTINCTIONS AND THE SCIENTIFIC METHOD  

EPA Science Inventory

Kangas (1992), Undiscovered species and the falsifiability of the tropical mass extinction hypotheses, ESA Bulletin 73:124-125, 1992, argues that there is a paradox concerning the mass extinctions projected from current rates of tropical deforestation. he parameters; for a given ...

354

Tropical deforestation and atmospheric carbon dioxide  

Microsoft Academic Search

Recent estimates of the net release of carbon to the atmosphere from deforestation in the tropics have ranged between 0.4 and 2.5 × 1015 g yr-1. Two things have happened to require a revision of these estimates. First, refinements of the methods used to estimate the stocks of carbon in the vegetation of tropical forests have produced new estimates that

R. A. Houghton

1991-01-01

355

Satellite detection of tropical burning in Brazil  

Microsoft Academic Search

Tropical burning often occurs in remote areas of the world. Satellite remote sensing is the only practical solution for detecting and monitoring this burning. In this paper we demonstrate the capability of the Advanced Very High Resolution Radiometer onboard the National Oceanic and Atmospheric Administration polar orbiting satellites for detecting tropical fire activity in the Manaus, Brazil area.

Michael Matson; Brent Holben

1987-01-01

356

Zooplankton, fish and fisheries in tropical freshwaters  

Microsoft Academic Search

About 40% of all fish species occur in freshwater, although only 1% of the globe is occupied by freshwaters. The tropics harbour a high percentage of these fishes. Freshwater zooplankton on the other hand is far less diverse than its marine counterpart and the tropics do not harbour a markedly high percentage of freshwater species either. The antecedents of freshwater

C. H. Fernando

1994-01-01

357

Objective classification of historical tropical cyclone intensity  

Microsoft Academic Search

Preinstrumental records of historical tropical cyclone activity require objective methods for accurately categorizing tropical cyclone intensity. Here wind force terms and damage reports from newspaper accounts in the Lesser Antilles and Jamaica for the period 1795-1879 are compared with wind speed estimates calculated from barometric pressure data. A total of 95 separate barometric pressure readings and colocated simultaneous wind force

Michael Chenoweth

2007-01-01

358

Objective classification of historical tropical cyclone intensity  

Microsoft Academic Search

Preinstrumental records of historical tropical cyclone activity require objective methods for accurately categorizing tropical cyclone intensity. Here wind force terms and damage reports from newspaper accounts in the Lesser Antilles and Jamaica for the period 1795–1879 are compared with wind speed estimates calculated from barometric pressure data. A total of 95 separate barometric pressure readings and colocated simultaneous wind force

Michael Chenoweth

2007-01-01

359

Priorities for Biodiversity Conservation in the Tropics  

NSDL National Science Digital Library

Biodiversity Bulletin No 1, from the World Conservation Monitoring Centre is now online and is entitled "Priorities for Biodiversity Conservation in the Tropics,"by Michael Green and others. The bulletin provides an assessment of "the extent to which habitats in the tropics are protected and guidance on prioritising conservation action from global and national perspectives."

Bunting, Gillian C.

1998-01-01

360

Rehabilitation of degraded tropical forest lands  

Microsoft Academic Search

The area of tropical forest lands in high rainfall areas that is already degraded is great and growing rapidly. Rehabilitation of such lands is important so their biological productivity can support people and reduce pressures for degradation of additional tropical forest lands. While further knowledge and experience is needed, there is a sufficient basis for trial programs. The economic and

Thomas E. Lovejoy

1985-01-01

361

Tropical Forests. Global Issues Education Packet.  

ERIC Educational Resources Information Center

Tropical forests provide the world with many products and an incredible diversity of plant and animal life. These forests also provide watershed areas, soil control, climate regulation, and winter homes for migrating birds from North America. It is believed that about 40% of tropical forests have already been destroyed in the last 20-30 years,…

Holm, Amy E.

362

TROPICAL SPIDERWORT SEEDBANK DYNAMICS AND LONGEVITY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tropical species are often expected to have short seedbank longevity and fairly predictable seedbank dynamics. This is not the case for tropical spiderwort (also known as Benghal dayflower, Commelina benghalensis L.). Although seedbanks near the surface appear to germinate rapidly – successively dep...

363

Tropical Semirings Jean-Eric Pin  

E-print Network

Tropical Semirings Jean-Eric Pin LITP/IBP, CNRS-Universit´e Paris 7 2 Place Jussieu, 75251 Paris of the boolean semiring in computer science. The aim of this paper is to present other semirings that occur in theoretical computer science. These semirings were baptized tropical semirings by Dominique Perrin in honour

Paris-Sud XI, Université de

364

ULTRADISCRETE CONNECTION MATRICES OVER A TROPICAL SEMIRING  

E-print Network

ULTRADISCRETE CONNECTION MATRICES OVER A TROPICAL SEMIRING C. ORMEROD Abstract. We consider linear systems of difference equations over the max- plus semiring. We extend theorems of Birkhoff et. al. to the realm of this tropical semiring by showing that under certain conditions one may define a connection

Sydney, University of

365

Use of tropical maize for bioethanol production  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tropical maize is an alternative energy crop being considered as a feedstock for bioethanol production in the North Central and Midwest United States. Tropical maize is advantageous because it produces large amounts of soluble sugars in its stalks, creates a large amount of biomass, and requires lo...

366

Global climate change and tropical ecosystems  

SciTech Connect

This book presents data on carbon pool fluxes from case studies in 12 countries in tropical regions. The chapters cover: Characteristics of tropical ecosystems; Soil and biotic carbon pools; Impacts of land use and soil management; Slash-and-burn practices; and Crop residue and fertility management.

Lal, R.; Eswaran, H.; Kimble, J.M.; Stewart, B.A. [eds.

2000-07-01

367

Monitoring tropical environments with space shuttle photography  

Microsoft Academic Search

Orbital photography from the Space Shuttle missions (1981–88) and earlier manned spaceflight programs (1962–1975) allows remote sensing time series to be constructed for observations of environmental change in selected portions of the global tropics. Particular topics and regions include deforestation, soil erosion, supersedimentation in streams, lacustrine, and estuarine environments, and desertification in the Greater Amazon, Tropical Africa and Madagascar, South

Michael R. Helfert; Kamlesh P. Lulla

1989-01-01

368

ORIGINAL ARTICLE Mitigation needs adaptation: Tropical forestry  

E-print Network

ORIGINAL ARTICLE Mitigation needs adaptation: Tropical forestry and climate change Manuel R adapt to this change. This paper discusses how tropical forestry practices can contribute to maintaining Forestry Research, P.O. Box 6596 JKPWB, Jakarta 10065, Indonesia e-mail: m.guariguata@cgiar.org J. P

Paris-Sud XI, Université de

369

Incorporation of analgesics into rodent embryo transfer protocols: assessing the effects on reproductive outcomes  

E-print Network

Surgical embryo transfer in rodents is a common procedure in today’s research laboratory, although little is known of the effect analgesics may have on not only the recipient female but also the embryos. Two perioperative analgesics, ketoprofen...

Burckhardt, Heather Ann

2009-05-15

370

Detection of Toxoplasma gondii by PCR and Mouse Bioassay in Rodents of Ahvaz District, Southwestern Iran  

PubMed Central

Toxoplasma gondii is obligate coccidian zoonotic parasite. Felidae family is definitive and wide ranges of warm-blooded vertebrates are intermediate hosts for the parasite. Rodents are measured as an important source of T. gondii infection for the definitive host. Thus, this study aimed to investigate Toxoplasm infection in rodents of Ahvaz district, southwest of Iran. A total of 100 rodents (73 Rattus norvegicus, 21 Rattus rattus, and 6 Mus musculus) were collected and studied by GRA6PCR and mouse bioassay. The finding indicated that 6 out of 100 (6%) and 2 out of 100 (2%) samples were positive by PCR and mouse bioassay, respectively. The results show notable chronic infection in the rodent and potential transmission of the infection among animal and men in the region. Accordingly, this study recommended investigating of the T. gondii infection in definitive and other intermediate hosts in other points of Khuzestan province, Southwest, Iran. PMID:24605327

Saki, J.; Khademvatan, S.

2014-01-01

371

Latitude drives diversification in Madagascar's endemic dry forest rodent Eliurus myoxinus  

E-print Network

Latitude drives diversification in Madagascar's endemic dry forest rodent Eliurus myoxinus, Madagascar 3 Association Vahatra, BP 3972, Antananarivo 101, Madagascar 4 Department of Zoology, Field Museum through western Madagascar. We sequenced the mitochondrial cytochrome b locus and nuclear introns

Yoder, Anne

372

RODENTS: PICTORIAL KEY TO SOME COMMON UNITED STATES GENERA Harold Georee Scott and Margery R. Borom  

E-print Network

HOUSE MOUSE Mus musculus #12;DOMESTIC RODENTS AND COCKROACHES: PICTORIAL KEY TO DROPPINGS Harold Georle.t with ridges ovoid, pointed with ridllU without rid,es length about 1/4-inch Mus musculus HOUSE MOUSE lenll

373

Acute and chronic toxicity of a lyophilised aqueous extract of Tanacetum vulgare leaves in rodents  

Microsoft Academic Search

Aim of the studyThe present investigation was carried out to evaluate the safety of an aqueous extract of tansy (Tanacetum vulgare L.) leaves by determining its potential toxicity after acute and chronic administration in rodents.

Sanaa Lahlou; Zafar H. Israili; Badiâa Lyoussi

2008-01-01

374

COMPARATIVE MICROARRAY EXPRESSION ANALYSIS OF SELECTED CANCER RELEVANT GENES IN HYPERTENSIVE RESISTANT VERSUS SUSCEPTIBLE RODENT STRAINS  

EPA Science Inventory

Hypertension and cancer are prevalent diseases. Epidemiological studies suggest that hypertension may increase the long term risk of cancer. Identification of resistance and/or susceptibility genes using rodent models could provide important insights into the management and treat...

375

Adaptation in Rodent Moles and Insectivorous Moles, and the Theory of Convergence  

Microsoft Academic Search

STUDIES in connexion with the life-history of the Orange Free State rodent mole, Cryptomys, brought to light a remarkable degree of adaptation, anatomically and psychologically, to its mode of life in total darkness.

G. Eloff

1951-01-01

376

Electromechanical design of a body weight support system for a therapeutic robot for rodent studies  

E-print Network

As part of an ongoing effort to better understand and treat locomotor disorders, an over-ground therapeutic robot prototype to study recovery of locomotion after spinal cord injury in rodents is under development. One key ...

Mayalu, Michaëlle Ntala

2010-01-01

377

Factors influencing repeated seed movements by scatter-hoarding rodents in an alpine forest.  

PubMed

Scatter-hoarding rodents are effective dispersal agents for many plant species. Several studies have shown that rodents repeatedly re-cache seeds. The re-caching process often has a significant impact on final seedling establishment, but the factors determining its occurrence are poorly understood. In this study, we followed the fate of 3564 artificial seeds that varied in size, nutrient content and tannin content. Seeds cached closer to their original releasing plots were more likely to be re-cached, and to a further distance. Larger seeds were more likely to be re-cached than smaller ones, while nutrient and tannin content had little effect. Most plant species that depend on scatter-hoarding rodents for seed dispersal bear relatively large seeds, and large seeds are usually more likely to be dispersed and to establish seedlings, suggesting that the caching preferences of scatter-hoarding rodents may have played an important role in the evolution of large seeds. PMID:24759374

Wang, Bo; Chen, Jin; Corlett, Richard T

2014-01-01

378

Rodent and Flea Abundance Fail to Predict a Plague Epizootic in Black-Tailed Prairie Dogs  

E-print Network

occurrence than are characteristics of rodent or flea species assemblages. Key Words: Boulder County--Colorado--Cynomys ludovicianus--Disease ecology--Pathogen dispersal--Yersinia pestis. Introduction Plague, the disease caused

Collinge, Sharon K.

379

TWO NEW SPECIES OF HYMENOLEPIS (CESTODA: HYMENOLEPIDIDAE) FROM MURID RODENTS (RODENTIA: MURIDAE) IN THE PHILIPPINES  

E-print Network

, parasitic in hedgehogs, and members of the genus Talpolepis, parasitic in moles. The cosmopolitan species apparatus, parasitic primarily in rodents, with a few species known from bats and 1 from hedgehogs. Members

Clayton, Dale H.

380

Factors influencing repeated seed movements by scatter-hoarding rodents in an alpine forest  

PubMed Central

Scatter-hoarding rodents are effective dispersal agents for many plant species. Several studies have shown that rodents repeatedly re-cache seeds. The re-caching process often has a significant impact on final seedling establishment, but the factors determining its occurrence are poorly understood. In this study, we followed the fate of 3564 artificial seeds that varied in size, nutrient content and tannin content. Seeds cached closer to their original releasing plots were more likely to be re-cached, and to a further distance. Larger seeds were more likely to be re-cached than smaller ones, while nutrient and tannin content had little effect. Most plant species that depend on scatter-hoarding rodents for seed dispersal bear relatively large seeds, and large seeds are usually more likely to be dispersed and to establish seedlings, suggesting that the caching preferences of scatter-hoarding rodents may have played an important role in the evolution of large seeds. PMID:24759374

Wang, Bo; Chen, Jin; Corlett, Richard T.

2014-01-01

381

Leishmania species: Detection and identification by nested PCR assay from skin samples of rodent reservoirs  

PubMed Central

Many rodent species act as reservoir hosts of zoonotic cutaneous leishmaniasis in endemic areas. In the present study a simple and reliable assay based on nested PCR was developed for the detection and identification of Leishmania parasites from rodent skin samples. We designed Leishmania-specific primers that successfully amplified ITS regions of Leishmania major, Leishmania gerbilli and Leishmania turanica using nested PCR. Out of 95 field collected Rhombomys opimus, 21 were positive by microscopic examination and 48 by nested PCR. The percentage of gerbils infected with L. major, L. gerbilli and L. turanica was 3.2%, 1.1% and 27.4%, respectively. In 15.8% of the rodents, we found mixed natural infections by L. major and L. turanica, 1.1% by L. major and L. gerbilli, and 2.1% by the three species. We concluded that this method is simple and reliable for detecting and identifying Leishmania species circulating in rodent populations. PMID:20566364

Akhavan, Amir Ahmad; Mirhendi, Hossein; Khamesipour, Ali; Alimohammadian, Mohammad Hossein; Rassi, Yavar; Bates, Paul; Kamhawi, Shaden; Valenzuela, Jesus G.; Arandian, Mohammad Hossein; Abdoli, Hamid; Jalali-zand, Niloufar; Jafari, Reza; Shareghi, Niloufar; Ghanei, Maryam; Yaghoobi-Ershadi, Mohammad Reza

2010-01-01

382

Segment Specification for the Payload Segment of the Reusable Reentry Satellite: Rodent Module Version  

NASA Technical Reports Server (NTRS)

The Reusable Reentry Satellite (RRS) System is composed of the payload segment (PS), vehicle segment (VS), and mission support (MS) segments. This specification establishes the performance, design, development, and test requirements for the RRS Rodent Module (RM).

1991-01-01

383

Analysis of protein pool of neuronal populations of cerebellar cortex in rodents of different species.  

PubMed

The protein pool of neuronal population of the cerebellar cortex was studied by interference cytometry in rodents occupying different ecological niches and differing by life style, nutrition habits, and motor activity. In all cell populations protein concentrations in the cytoplasm were higher than in the nucleus in all studied rodents and did not depend on the functional characteristics of neurons. The extreme values of protein content were determined for populations of granular and ganglion cells. High protein concentrations per volume unit of cell structure were detected in functionally different cerebellar neurons of gray rats, characterized by high motor activity and a certain degree of synanthropy, while low values were detected in mole rats, slow-moving underground rodents. Therefore, the specific protein pool of neuronal populations of the cerebellar cortex of rodents can be regarded as adaptation to habitation conditions. PMID:11276318

Orlyanskaya, T Y; Lyutikova, T M

2000-12-01

384

The helminthic parasites of rodents in Dakahlia Governorate, with reference to their Egyptian helminth fauna.  

PubMed

No doubt, rodents are among the most important reservoirs of zoonotic diseases. This paper aimed to survey the helminth fauna of the different species of rodents in Dakahlia Governorate. Eight species of rodents were encountered in the different centers examined. A total of fifteen species of helminthic parasites were found. They belong to four classes: Trematoda five species: H. heterophyes, H. pumilio, H. yokogawai, S. tridactyla and E. callawayensis, Cestoidea three species: H diminuta, H. nana and T. taeniaeformis, Nematoda six species: A. cantonensis, T. muris, C. hepatica, S. obvelata, S. muris, S. ratti, and Archiacanthocephala one species: M. moniliformis. The medical and/or veterinary importance of these parasites were discussed. It was concluded that rodents are the most serious source of zoonotic parasites. PMID:8077761

el Shazly, A M; Morsy, T A; el Kady, G A; Ragheb, D A; Handousa, A E; Ahmed, M M; Younis, T A; Habib, K S

1994-08-01

385

Evidence for rodent-common and species-typical limb and digit use in eating, derived from a comparative analysis of ten rodent species.  

PubMed

Order Rodentia comprises a vast portion of mammalian species (1814 species), which occupy extremely diverse habitats requiring very distinct motor specializations (e.g. burrowing, hopping, climbing, flying and swimming). Although early classification of paw use ability suggests rodents are impoverished relative to primates and make little use of their paws, there have been no systematic investigations of paw use in rodents. The present study was undertaken to describe limb/paw movements in a variety of common rodents. The movements used for handling sunflower seeds and other foods were videorecorded and analyzed in the guinea pig (Cavia porcellus), Mongolian gerbil (Meriones unguiculatus), Syrian hamster (Mesocricetus auratus), laboratory mouse (Mus musculus), laboratory rat (Rattus norvegicus), gray squirrel (Sciurus carolinensis), red squirrel (Tamiasciurus hudsonicus), Richardson's ground squirrel (Spermophilus richardsonni), prairie dog (Cynomus parvidens), and Canadian beaver (Castor americanus). The results suggested five order-common movements of food handling: (1) locating food by sniffing, (2) grasping food by mouth, (3) sitting back on the haunches to eat, (4) grasping the food using an elbow-in movement, and (5) manipulate the food with the digits. Different species displayed species-typical specializations including (1) bilateral grasping with the paws (gerbil), (2) unilateral grasping with a paw (beaver), (3) unilateral holding (ground squirrels), (4) various grip and digit postures (all species), (5) unilateral object removal from the mouth (gerbil), (6) bilateral thumb holding (squirrels), and (7) simultaneous holding/manipulation of two objects (squirrels). Only the guinea pig did not handle food with its paws, suggesting its behavior is regressive. The existence of a core pattern of paw and digit use in rodents suggests that skilled limb and paw movements originate at least with the common ancestors of the rodent, and likely the common ancestor to rodent and primate lineages, while species-typical movements suggest specialization/regression of limb use has occurred in a number of mammalian orders. PMID:9821545

Whishaw, I Q; Sarna, J R; Pellis, S M

1998-11-01

386

Tick parasites of rodents in Romania: host preferences, community structure and geographical distribution  

PubMed Central

Background Ticks are among the most important vectors of zoonotic diseases in temperate regions of Europe, with widespread distribution and high densities, posing an important medical risk. Most ticks feed on a variety of progressively larger hosts, with a large number of small mammal species typically harbouring primarily the immature stages. However, there are certain Ixodidae that characteristically attack micromammals also during their adult stage. Rodents are widespread hosts of ticks, important vectors and competent reservoirs of tick-borne pathogens. Micromammal-tick associations have been poorly studied in Romania, and our manuscript shows the results of a large scale study on tick infestation epidemiology in rodents from Romania. Methods Rodents were caught using snap-traps in a variety of habitats in Romania, between May 2010 and November 2011. Ticks were individually collected from these rodents and identified to species and development stage. Frequency, mean intensity, prevalence and its 95% confidence intervals were calculated using the EpiInfo 2000 software. A p value of <0.05 was considered statistically significant. Results We examined 423 rodents (12 species) collected from six counties in Romania for the presence of ticks. Each collected tick was identified to species level and the following epidemiological parameters were calculated: prevalence, mean intensity and mean abundance. The total number of ticks collected from rodents was 483, with eight species identified: Ixodes ricinus, I. redikorzevi, I. apronophorus, I. trianguliceps, I. laguri, Dermacentor marginatus, Rhipicephalus sanguineus and Haemaphysalis sulcata. The overall prevalence of tick infestation was 29.55%, with a mean intensity of 3.86 and a mean abundance of 1.14. Only two polyspecific infestations were found: I. ricinus + I. redikorzevi and I. ricinus + D. marginatus. Conclusions Our study showed a relatively high diversity of ticks parasitizing rodents in Romania. The most common tick in rodents was I. ricinus, followed by I. redikorzevi. Certain rodents seem to host a significantly higher number of tick species than others, the most important within this view being Apodemus flavicollis and Microtus arvalis. The same applies for the overall prevalence of tick parasitism, with some species more commonly infected (M. arvalis, A. uralensis, A. flavicollis and M. glareolus) than others. Two rodent species (Mus musculus, Rattus norvegicus) did not harbour ticks at all. Based on our results we may assert that rodents generally can act as good indicators for assessing the distribution of certain tick species. PMID:23171665

2012-01-01

387

Tropical Cyclones as a Critical Phenomenon  

E-print Network

It has been proposed that the number of tropical cyclones as a function of the energy they release is a decreasing power-law function, up to a characteristic energy cutoff determined by the spatial size of the ocean basin in which the storm occurs. This means that no characteristic scale exists for the energy of tropical cyclones, except for the finite-size effects induced by the boundaries of the basins. This has important implications for the physics of tropical cyclones. We discuss up to what point tropical cyclones are related to critical phenomena (in the same way as earthquakes, rainfall, etc.), providing a consistent picture of the energy balance in the system. Moreover, this perspective allows one to visualize more clearly the effects of global warming on tropical-cyclone occurrence.

Corral, A

2011-01-01

388

Scaling of Tropical-Cyclone Dissipation  

E-print Network

The influence of climate variability and global warming on the occurrence of tropical cyclones (TC) is a controversial issue. Existing historical databases on the subject are not fully reliable, but a more fundamental hindrance is the lack of basic understanding regarding the intrinsic nature of tropical cyclone genesis and evolution. It is known that tropical cyclones involve more than a passive response to changing external forcing, but it is not clear which dynamic behaviour best describes them. Here we present a new approach based on the application of the power dissipation index (PDI), which constitutes an estimation of released energy, to individual tropical cyclones. A robust law emerges for the statistics of PDI, valid in four different ocean basins and over long time periods. In addition to suggesting a novel description of the physics of tropical cyclones in terms of critical phenomena, the law allows to quantify their response to changing climatic conditions, with an increase in the largest PDI val...

Osso, Albert; Llebot, J E

2009-01-01

389

Chemical cues used by prairie rattlesnakes (Crotalus viridis) to follow trails of rodent prey.  

PubMed

Each of 10 prairie rattlesnakes (Crotalus viridis) was exposed to three types of trails after striking rodent prey (Mus musculus). One trail was made with mouse urine, another was made with tap water, and the third consisted of materials from mouse integument. The snakes exhibited trailing behavior only when integumentary trails were available. It was concluded that prairie rattlesnakes do not utilize urinary cues; instead they attend to materials associated with rodent skin and fur. PMID:24264897

Chiszar, D; Melcer, T; Lee, R; Radcliffe, C W; Duvall, D

1990-01-01

390

Distinct Leishmania Species Infecting Wild Caviomorph Rodents (Rodentia: Hystricognathi) from Brazil  

PubMed Central

Background Caviomorph rodents, some of the oldest Leishmania spp. hosts, are widely dispersed in Brazil. Despite both experimental and field studies having suggested that these rodents are potential reservoirs of Leishmania parasites, not more than 88 specimens were analyzed in the few studies of natural infection. Our hypothesis was that caviomorph rodents are inserted in the transmission cycles of Leishmania in different regions, more so than is currently recognized. Methodology We investigated the Leishmania infection in spleen fragments of 373 caviomorph rodents from 20 different species collected in five Brazilian biomes in a period of 13 years. PCR reactions targeting kDNA of Leishmania sp. were used to diagnose infection, while Leishmania species identification was performed by DNA sequencing of the amplified products obtained in the HSP70 (234) targeting. Serology by IFAT was performed on the available serum of these rodents. Principal findings In 13 caviomorph rodents, DNA sequencing analyses allowed the identification of 4 species of the subgenus L. (Viannia): L. shawi, L. guyanensis, L. naiffi, and L. braziliensis; and 1 species of the subgenus L. (Leishmania): L. infantum. These include the description of parasite species in areas not previously included in their known distribution: L. shawi in Thrichomys inermis from Northeastern Brazil and L. naiffi in T. fosteri from Western Brazil. From the four other positive rodents, two were positive for HSP70 (234) targeting but did not generate sequences that enabled the species identification, and another two were positive only in kDNA targeting. Conclusions/Significance The infection rate demonstrated by the serology (51.3%) points out that the natural Leishmania infection in caviomorph rodents is much higher than that observed in the molecular diagnosis (4.6%), highlighting that, in terms of the host species responsible for maintaining Leishmania species in the wild, our current knowledge represents only the “tip of the iceberg.” PMID:25503973

Cássia-Pires, Renata; Boité, Mariana C.; D'Andrea, Paulo S.; Herrera, Heitor M.; Cupolillo, Elisa; Jansen, Ana Maria; Roque, André Luiz R.

2014-01-01

391

Wide Distribution and Genetic Diversity of “Candidatus Neoehrlichia mikurensis” in Rodents from China  

PubMed Central

“Candidatus Neoehrlichia mikurensis” was detected by PCR in 4.0% (34/841) of the rodents tested in this study. The 34 rodents represented nine species from seven regions of China. Phylogenetic analyses based on the partial groEL and nearly entire 16S rRNA gene sequences of the agent revealed genetic diversity, which was correlated with its geographic origins. PMID:23183973

Li, Hao; Jiang, Jiafu; Tang, Fang; Sun, Yi; Li, Zengde; Zhang, Weilong; Gong, Zhengda; Liu, Kun; Yang, Hong

2013-01-01

392

Two-phase seed dispersal: linking the effects of frugivorous birds and seed-caching rodents  

Microsoft Academic Search

Frugivorous birds disperse the seeds of many fruit-bearing plants, but the fate of seeds after defecation or regurgitation\\u000a is often unknown. Some rodents gather and scatter hoard seeds, and some of these may be overlooked, germinate, and establish\\u000a plants. We show that these two disparate modes of seed dispersal are linked in some plants. Rodents removed large (>25 mg)\\u000a seeds from

Stephen B. Vander Wall; Kellie M. Kuhn; Jennifer R. Gworek

2005-01-01

393

Patterns of Rodent Abundance on Open-Space Grasslands in Relation to Suburban Edges  

Microsoft Academic Search

Relatively little is known about the response of grassland rodent populations to urban and subur- ban edges. We live-trapped rodents for three summers on 65 3.1-ha grassland plots on open space of the city of Boulder, Colorado, and compared capture rates among species according to habitat type, percentage of the 40 ha surrounding each plot that was suburbanized, and proximity

Carl E. Bock; Kerri T. Vierling; Sandra L. Haire; John D. Boone; William W. Merkle

2002-01-01

394

Tropical Rainfall Measuring Mission (TRMM)  

NSDL National Science Digital Library

The Tropical Rainfall Measuring Mission (TRMM) satellite is a joint mission between NASA and the National Space Development Agency (NSDA) of Japan. It is designed to monitor and study tropical rainfall and the associated release of energy that helps to power the global water cycle. The satellite can greatly enhance our understanding of the interactions which produce changes in global rainfall and climate. A detailed overview of TRMM covers why we need TRMM, which is broken into grade-specific explanations; questions and answers about TRMM; TRMM instruments; climate-related facts; the Mission to Planet Earth "Education" Homepage; and case studies comparing land and ocean storms. Images showing current conditions, as well as archived images, movies, and animations are provided on hurricanes, global datasets covering lightning, temperature, and rainfall, monthly mean rainrates from 1998 through 2000, monthly rainfall anomalies, data types and idealized data simulations. Also archived are press releases, refereed journals, and scientific documents related to TRMM data information. An Educational Resources section provides teacher's guides, animations and activities on topics such as latent heat of evaporation and the water cycle, hurricanes as heat engines, air pressure systems in the context of El Nino/La Nina, lightning formation and the role of ice in a thunderstorm, and remote sensing of precipitation. The ground-based validation efforts of the TRMM are outlined in detail. Related organizations, data sources, field experiments, and TRMM research are linked from this site.

395

Bridges to sustainable tropical health  

PubMed Central

Ensuring sustainable health in the tropics will require bridge building between communities that currently have a limited track record of interaction. It will also require new organizational innovation if much of the negative health consequences of large-scale economic development projects are to be equitably mitigated, if not prevented. We focus attention on three specific contexts: (i) forging linkages between the engineering and health communities to implement clean water and sanitation on a broad scale to prevent reworming, after the current deworming-only programs, of people by diverse intestinal parasites; (ii) building integrated human and animal disease surveillance infrastructure and technical capacity in tropical countries on the reporting and scientific evidence requirements of the sanitary and phytosanitary agreement under the World Trade Organization; and (iii) developing an independent and equitable organizational structure for health impact assessments as well as monitoring and mitigation of health consequences of economic development projects. Effective global disease surveillance and timely early warning of new outbreaks will require a far closer integration of veterinary and human medicine than heretofore. Many of the necessary surveillance components exist within separate animal- and human-oriented organizations. The challenge is to build the necessary bridges between them. PMID:17913894

Singer, Burton H.; de Castro, Marcia Caldas

2007-01-01

396

Tropical pulmonary eosinophilia - A review  

PubMed Central

Tropical pulmonary eosinophilia (TPE) is a syndrome of wheezing, fever and eosiniphilia seen predominantly in the Indian subcontinent and other tropical areas. Its etiological link with Wuchereria bancrofti and Brugia malayi has been well established. The pathogenesis is due to an exaggerated immune response to the filarial antigens which includes type I, type III and type IV reactions with eosinophils playing a pivotal role. Peripheral blood eosinophilia is usually striking with levels over 3000/?l being common. High serum levels of IgE and filarial-specific IgE and IgG are also found. The pathology may vary from an acute eosinophilic alveolitis to histiocytic infiltration depending on the stage of the disease. While earlier studies had suggested that the disease runs a benign course, more recent work has shown that untreated TPE could result in a fair degree of respiratory morbidity. Pulmonary function tests may show a mixed restrictive and obstructive abnormality with a reduction in diffusion capacity. The bronchoalveolar lavage (BAL) eosinophil count has a negative correlation with the diffusion capacity. Treatment consists of diethylcarbamazine (DEC) for at least three weeks. Despite treatment with DEC, about 20 per cent of patients may relapse. Steroids have shown to have a beneficial effect but the exact dose and duration is yet to be confirmed by randomized controlled trials. A specific and easily available marker is required for TPE in order to distinguish it from other parasitic and non-parasitic causes of pulmonary eosinophilia. PMID:24135173

Mullerpattan, Jai B.; Udwadia, Zarir F.; Udwadia, Farokh E.

2013-01-01

397

Simulation of Tropical Biomass Burning  

NASA Technical Reports Server (NTRS)

The work proposed was carried out as planned. The work described in this final report formed the basis for a follow-on research grant research grant from NASA Ames Research Center. The research objectives that were achieved during the course of our studies include the following: (1) the evaluation of several components of MM5 (Meteorological Model 5 version 2) and the Global/Regional Atmospheric Chemistry Event Simulator (GRACES) combined modeling system; (2) improved calculations of the transport of tracers for both NASA airborne missions, Study of Ozone and Nitrogen oxides experiment (SONEX) and Pacific Exploratory MIssion in the Tropics (PEM-Tropics); (3) improved source strength estimates for isoprene, dust and similar emissions from the Earth's surface. This required the use of newly available databases on the Earth's surface and vegetation; (4) completed atmospheric chemistry simulations of radicals and nitrogen oxide species; (5)improved the handling of cumulonimbus convection by modifying the existing scheme; (6) identified the role of the African Intertropical Front, using MM5's nesting capability to refine model resolution in crucial areas; modified the MM5 trajectory program to allow it to work much better for a parcel crossing the west/east boundaries.

Hamill, Patrick; Guo, Zitian

1998-01-01

398

Mission Investigates Tropical Cirrus Clouds  

NASA Astrophysics Data System (ADS)

It has been a year since NASA conducted the highly successful Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment Study (CRYSTAL-FACE). The measurement campaign was designed to investigate the physical properties and formation processes of tropical cirrus clouds. CRYSTAL-FACE was sponsored by NASA's Earth Science Enterprise as an integral component of its Earth observation research strategy, and included substantial collaboration with the National Oceanic and Atmospheric Administration, the National Science Foundation, the Department of Energy, and the Naval Research Laboratory. During July 2002, the mission's six aircraft (NASA ER-2, NASA WB-57, Scaled Composites Proteus, University of North Dakota Citation, NSF-supported NRL P-3, and NRL Twin Otter) operated from the Key West Naval Air Facility. In addition, ground sites were located at the Tamiami airport on the east coast of Florida and near Everglades City on the west coast of Florida. Aircraft and ground site measurements are listed in Table 1. Data archiving is complete, and the data are now available to the general scientific community. Detailed instrument descriptions as well as the final data can be found on the CRYSTAL-FACE Web site (http://cloud1.arc.nasa.gov/crystalface/).

Jenson, Eric; Starr, David; Toon, Owen B.

2004-02-01

399

A comparison of bats and rodents as reservoirs of zoonotic viruses: are bats special?  

PubMed

Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs. PMID:23378666

Luis, Angela D; Hayman, David T S; O'Shea, Thomas J; Cryan, Paul M; Gilbert, Amy T; Pulliam, Juliet R C; Mills, James N; Timonin, Mary E; Willis, Craig K R; Cunningham, Andrew A; Fooks, Anthony R; Rupprecht, Charles E; Wood, James L N; Webb, Colleen T

2013-04-01

400

A comparison of bats and rodents as reservoirs of zoonotic viruses: are bats special?  

USGS Publications Warehouse

Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs.

Luis, Angela D.; Hayman, David T.S.; O'Shea, Thomas J.; Cryan, Paul M.; Gilbert, Amy T.; Pulliam, Juliet R.C.; Mills, James N.; Timonin, Mary E.; Willis, Craig K.R.; Cunningham, Andrew A.; Fooks, Anthony R.; Rupprecht, Charles E.; Wood, James L.N.; Webb, Colleen T.

2013-01-01

401

A comparison of bats and rodents as reservoirs of zoonotic viruses: are bats special?  

PubMed Central

Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs. PMID:23378666

Luis, Angela D.; Hayman, David T. S.; O'Shea, Thomas J.; Cryan, Paul M.; Gilbert, Amy T.; Pulliam, Juliet R. C.; Mills, James N.; Timonin, Mary E.; Willis, Craig K. R.; Cunningham, Andrew A.; Fooks, Anthony R.; Rupprecht, Charles E.; Wood, James L. N.; Webb, Colleen T.

2013-01-01

402

Bartonella Genotypes in Fleas (Insecta: Siphonaptera) Collected from Rodents in the Negev Desert, Israel?  

PubMed Central

Fleas collected from rodents in the Negev Desert in southern Israel were molecularly screened for Bartonella species. A total of 1,148 fleas, collected from 122 rodents belonging to six species, were pooled in 245 pools based on flea species, sex, and rodent host species. Two Bartonella gene fragments, corresponding to RNA polymerase B (rpoB) and citrate synthase (gltA), were targeted, and 94 and 74 flea pools were found positive by PCR, respectively. The Bartonella 16S-23S internal transcribed spacer (ITS) region was also targeted, and 66 flea pools were found to be positive by PCR. Sixteen different Bartonella gltA genotypes were detected in 94 positive flea pools collected from 5 different rodent species, indicating that fleas collected from each rodent species can harbor several Bartonella genotypes. Based on gltA analysis, identified Bartonella genotypes were highly similar or identical to strains previously detected in rodent species from different parts of the world. A gltA fragment 100% similar to Bartonella henselae was detected in one flea pool. Another 2 flea pools contained gltA fragments that were closely related to B. henselae (98% similarity). The high sequence similarities to the zoonotic pathogen B. henselae warrant further investigation. PMID:20802081

Morick, Danny; Krasnov, Boris R.; Khokhlova, Irina S.; Shenbrot, Georgy I.; Kosoy, Michael Y.; Harrus, Shimon

2010-01-01

403

Prevalence and Diversity of Bartonella Species in Commensal Rodents and Ectoparasites from Nigeria, West Africa  

PubMed Central

Background Bartonellae are fastidious bacteria causing persistent bacteremia in humans and a wide variety of animals. In recent years there is an increasing interest in mammalian bartonelloses in general and in rodent bartonelloses in particular. To date, no studies investigating the presence of Bartonella spp. in rodents and ectoparasites from Nigeria were carried out. Methodology/Principal Findings The aim of the current study was to investigate the presence of Bartonella spp. in commensal rodents and their ectoparasites in Nigeria. We report, for the first time, the molecular detection of Bartonella in 26% (46/177) of commensal rodents (Rattus rattus, R. norvegicus and Cricetomys gambianus) and 28% (9/32) of ectoparasite pools (Xenopsylla cheopis, Haemolaelaps spp., Ctenophthalmus spp., Hemimerus talpoides, and Rhipicephalus sanguineus) from Nigeria. Sequence analysis of the citrate synthase gene (gltA) revealed diversity of Bartonella spp. and genotypes in Nigerian rodents and their ectoparasites. Bartonella spp. identical or closely related to Bartonella elizabethae, Bartonella tribocorum and Bartonella grahamii were detected. Conclusions/Significance High prevalence of infection with Bartonella spp. was detected in commensal rodents and ectoparasites from Nigeria. The Bartonella spp. identified were previously associated with human diseases highlighting their importance to public health. Further studies need to be conducted to determine whether the identified Bartonella species could be responsible for human cases of febrile illness in Nigeria. PMID:23738028

Kamani, Joshua; Morick, Danny; Mumcuoglu, Kosta Y.; Harrus, Shimon

2013-01-01

404

Middle Eocene rodents from Peruvian Amazonia reveal the pattern and timing of caviomorph origins and biogeography  

PubMed Central

The long-term isolation of South America during most of the Cenozoic produced a highly peculiar terrestrial vertebrate biota, with a wide array of mammal groups, among which caviomorph rodents and platyrrhine primates are Mid-Cenozoic immigrants. In the absence of indisputable pre-Oligocene South American rodents or primates, the mode, timing and biogeography of these extraordinary dispersals remained debated. Here, we describe South America's oldest known rodents, based on a new diverse caviomorph assemblage from the late Middle Eocene (approx. 41 Ma) of Peru, including five small rodents with three stem caviomorphs. Instead of being tied to the Eocene/Oligocene global cooling and drying episode (approx. 34 Ma), as previously considered, the arrival of caviomorphs and their initial radiation in South America probably occurred under much warmer and wetter conditions, around the Mid-Eocene Climatic Optimum. Our phylogenetic results reaffirm the African origin of South American rodents and support a trans-Atlantic dispersal of these mammals during Middle Eocene times. This discovery further extends the gap (approx. 15 Myr) between first appearances of rodents and primates in South America. PMID:21993503

Antoine, Pierre-Olivier; Marivaux, Laurent; Croft, Darin A.; Billet, Guillaume; Ganerød, Morgan; Jaramillo, Carlos; Martin, Thomas; Orliac, Maëva J.; Tejada, Julia; Altamirano, Ali J.; Duranthon, Francis; Fanjat, Grégory; Rousse, Sonia; Gismondi, Rodolfo Salas

2012-01-01

405

Environmental genotoxicity evaluation using cytogenetic end points in wild rodents.  

PubMed Central

We analyzed cytogenetic end points in three populations of two species of wild rodents--Akodon montensis and Oryzomys nigripes--living in an industrial, an agricultural, and a preservation area at the Itajaí Valley, state of Santa Catarina, Brazil. Our purpose was to evaluate the performance of the following end points in the establishment of a genotoxic profile of each area: the polychromatic/normochromatic cell ratio; the mitotic index; the frequency of micronucleated cells both in the bone marrow and peripheral blood; and the frequency of cells with chromosome aberrations in the bone marrow. Preparations were obtained using conventional cytogenetic techniques. The results showed a) the role of the end points used as biomarkers in the early detection of genotoxic agents and in the identification of species and populations at higher risk; b) the difference in sensitivity of the species selected as bioindicators in relation to the cytogenetic end points analyzed; c) the need to use at least two sympatric species to detect the presence of genotoxins in each locality; and d) the need to use several end points when trying to establish a genotoxic profile of an area. PMID:11133397

de Souza Bueno, A M; de Bragança Pereira, C A; Rabello-Gay, M N

2000-01-01

406

WNT signaling underlies the pathogenesis of neuropathic pain in rodents  

PubMed Central

Treating neuropathic pain is a major clinical challenge, and the underlying mechanisms of neuropathic pain remain elusive. We hypothesized that neuropathic pain–inducing nerve injury may elicit neuronal alterations that recapitulate events that occur during development. Here, we report that WNT signaling, which is important in developmental processes of the nervous system, plays a critical role in neuropathic pain after sciatic nerve injury and bone cancer in rodents. Nerve injury and bone cancer caused a rapid-onset and long-lasting expression of WNTs, as well as activation of WNT/frizzled/?-catenin signaling in the primary sensory neurons, the spinal dorsal horn neurons, and astrocytes. Spinal blockade of WNT signaling pathways inhibited the production and persistence of neuropathic pain and the accompanying neurochemical alterations without affecting normal pain sensitivity and locomotor activity. WNT signaling activation stimulated production of the proinflammatory cytokines IL-18 and TNF-? and regulated the NR2B glutamate receptor and Ca2+-dependent signals through the ?-catenin pathway in the spinal cord. These findings indicate a critical mechanism underlying the pathogenesis of neuropathic pain and suggest that targeting the WNT signaling pathway may be an effective approach for treating neuropathic pain, including bone cancer pain. PMID:23585476

Zhang, Yan-Kai; Huang, Zhi-Jiang; Liu, Su; Liu, Yue-Peng; Song, Angela A.; Song, Xue-Jun

2013-01-01

407

OCT-aided anastomosis platform study in the rodent model  

NASA Astrophysics Data System (ADS)

Anastomosis is one of the most commonly performed procedure in the clinical environment that involves tubular structures, such as blood vessel, lymphatic vessel, seminal duct and ureter. Suture based anastomosis is still the foundation for most basic surgical training and clinical operation, although alternate techniques have been developed and under development. For those tubular-structure-anastomosis, immediate real-time post-operative evaluation of the surgical outcome is critical to the success of surgery. Previously evaluation is mostly based on surgeons' experience. Fourier-domain optical coherence tomography is high-speed, high-resolution noninvasive 3D imaging modality that has been widely used in the biomedical research and clinical study. In this study we used Fourier-domain optical coherence tomography as an evaluation tool for anastomosis of lymphatic vessels, ureter and seminal duct in rodent model. Immediate post-operative and long term surgical site data were collected and analyzed. Critical clinical parameters such as lumen patency, anastomosed site narrowing and suture error detection are provided to surgeons.

Huang, Yong; Tong, Dedi; Zhu, Shan; Wu, Lehao; Ibrahim, Zuhaib; Lee, WP Andrew; Brandacher, Gerald; Kang, Jin U.

2014-02-01

408

Development of contrast-enhanced rodent imaging using functional CT  

NASA Astrophysics Data System (ADS)

Micro-computed tomography (microCT) is capable of obtaining high-resolution images of skeletal tissues. However its image contrast among soft tissues remains inadequate for tumor detection. High speed functional computed tomography will be needed to image tumors by employing x-ray contrast medium. The functional microCT development will not only facilitate the image contrast enhancement among different tissues but also provide information of tumor physiology. To demonstrate the feasibility of functional CT in mouse imaging, sequential computed tomography is performed in mice after contrast material administration using a high-speed clinical CT scanner. Although the resolution of the clinical scanner is not sufficient to dissolve the anatomic details of rodents, bulky physiological parameters in major organs such as liver, kidney, pancreas, and ovaries (testicular) can be examined. For data analysis, a two-compartmental model is employed and implemented to characterize the tissue physiological parameters (regional blood flow, capillary permeability, and relative compartment volumes.) The measured contrast dynamics in kidneys are fitted with the compartmental model to derive the kidney tissue physiology. The study result suggests that it is feasible to extract mouse tissue physiology using functional CT imaging technology.

Liang, Yun; Stantz, Keith M.; Krishnamurthi, Ganapathy; Steinmetz, Rosemary; Hutchins, Gary D.

2003-05-01

409

In vivo Optogenetic Stimulation of the Rodent Central Nervous System.  

PubMed

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution has been a long sought tool for neuroscientists in the systems-level search for the neural circuitry governing complex behavioral states. Optogenetics is a cutting-edge tool that is revolutionizing the field of neuroscience and represents one of the first systematic approaches to enable causal testing regarding the relation between neural signaling events and behavior. By combining optical and genetic approaches, neural signaling can be bi-directionally controlled through expression of light-sensitive ion channels (opsins) in mammalian cells. The current protocol describes delivery of specific wavelengths of light to opsin-expressing cells in deep brain structures of awake, freely-moving rodents for neural circuit modulation. Theoretical principles of light transmission as an experimental consideration are discussed in the context of performing in vivo optogenetic stimulation. The protocol details the design and construction of both simple and complex laser configurations and describes tethering strategies to permit simultaneous stimulation of multiple animals for high-throughput behavioral testing. PMID:25651158

Sidor, Michelle M; Davidson, Thomas J; Tye, Kay M; Warden, Melissa R; Diesseroth, Karl; McClung, Colleen A

2015-01-01

410

Sexual Differentiation of the Rodent Brain: Dogma and Beyond  

PubMed Central

Steroid hormones of gonadal origin act on the neonatal brain to produce sex differences that underlie adult reproductive physiology and behavior. Neuronal sex differences occur on a variety of levels, including differences in regional volume and/or cell number, morphology, physiology, molecular signaling, and gene expression. In the rodent, many of these sex differences are determined by steroid hormones, particularly estradiol, and are established by diverse downstream effects. One brain region that is potently organized by estradiol is the preoptic area (POA), a region critically involved in many behaviors that show sex differences, including copulatory and maternal behaviors. This review focuses on the POA as a case study exemplifying the depth and breadth of our knowledge as well as the gaps in understanding the mechanisms through which gonadal hormones produce lasting neural and behavioral sex differences. In the POA, multiple cell types, including neurons, astrocytes, and microglia are masculinized by estradiol. Multiple downstream molecular mediators are involved, including prostaglandins, various glutamate receptors, protein kinase A, and several immune signaling molecules. Moreover, emerging evidence indicates epigenetic mechanisms maintain sex differences in the POA that are organized perinatally and thereby produce permanent behavioral changes. We also review emerging strategies to better elucidate the mechanisms through which genetics and epigenetics contribute to brain and behavioral sex differences. PMID:22363256

Lenz, Kathryn M.; Nugent, Bridget M.; McCarthy, Margaret M.

2012-01-01

411

Validating Excised Rodent Lungs for Functional Hyperpolarized Xenon-129 MRI  

PubMed Central

Ex vivo rodent lung models are explored for physiological measurements of respiratory function with hyperpolarized (hp) 129Xe MRI. It is shown that excised lung models allow for simplification of the technical challenges involved and provide valuable physiological insights that are not feasible using in vivo MRI protocols. A custom designed breathing apparatus enables MR images of gas distribution on increasing ventilation volumes of actively inhaled hp 129Xe. Straightforward hp 129Xe MRI protocols provide residual lung volume (RV) data and permit for spatially resolved tracking of small hp 129Xe probe volumes during the inhalation cycle. Hp 129Xe MRI of lung function in the excised organ demonstrates the persistence of post mortem airway responsiveness to intravenous methacholine challenges. The presented methodology enables physiology of lung function in health and disease without additional regulatory approval requirements and reduces the technical and logistical challenges with hp gas MRI experiments. The post mortem lung functional data can augment histological measurements and should be of interest for drug development studies. PMID:24023683

Lilburn, David M. L.; Hughes-Riley, Theodore; Six, Joseph S.; Stupic, Karl F.; Shaw, Dominick E.; Pavlovskaya, Galina E.; Meersmann, Thomas

2013-01-01

412

Age structure, residents, and transients of Miocene rodent communities.  

PubMed

The age structures of two successive rodent communities are studied on the basis of a rich record from well-dated Miocene sections (17-10 Ma) in north-central Spain. Community age is defined as the mean of the residence times of the community members at the time of the locality age. Community ages are negatively correlated with the numbers of community members. These members are divided into residents (with continuous membership times > or =1.54 million years) and transients (with membership times <1.54 million years). During episodes of species loss, there is a preferential disappearance of transients while residents are retained, a pattern referred to as the "seniority rule." The residents define the studied communities. They are associated with early successional stages of vegetation, and transients are associated with later stages. Under stable conditions, early arrivals in succession are "transient" and replaced by competitive later arrivals. The reversed roles of transients and residents in the studied fossil record are explained by assuming high degrees of disturbance. We view the system within the context of nonequilibrium metapopulation theory, in which competitively superior species become transients because of their dependence on ephemeral late successional habitats. PMID:15791531

van der Meulen, Albert J; Peláez-Campomanes, Pablo; Levin, Simon A

2005-04-01

413

A new rodent behavioral paradigm for studying forelimb movement  

PubMed Central

The center-out task is a standard paradigm often used to study the neural control of reaching movements in human and non-human primates. However, there are several disadvantages to the use of monkeys, notably costs, infrastructural requirements, and ethical considerations. Here we describe a similar task designed to examine forelimb movements in rats. Rats were trained to grasp a joystick with their forepaw and use it to control the movements of a sipper tube in two dimensions. The rats learned to move the joystick in four directions with at least 70% accuracy after about 45 days of training. In addition, rats were able to learn a reversed mapping between joystick and sipper tube movement. This is a more complicated behavior than has been previously demonstrated for rats, and it could allow more motor behavior studies to be conducted in rodents instead of monkeys. We currently are using this behavior to decode the rats’ forelimb movements from their brain signals. PMID:20691727

Slutzky, Marc W.; Jordan, Luke R.; Bauman, Matthew J.; Miller, Lee E.

2010-01-01

414

Traumatic Brain Injury – Modeling Neuropsychiatric Symptoms in Rodents  

PubMed Central

Each year in the US, ?1.5 million people sustain a traumatic brain injury (TBI). Victims of TBI can suffer from chronic post-TBI symptoms, such as sensory and motor deficits, cognitive impairments including problems with memory, learning, and attention, and neuropsychiatric symptoms such as depression, anxiety, irritability, aggression, and suicidal rumination. Although partially associated with the site and severity of injury, the biological mechanisms associated with many of these symptoms – and why some patients experience differing assortments of persistent maladies – are largely unknown. The use of animal models is a promising strategy for elucidation of the mechanisms of impairment and treatment, and learning, memory, sensory, and motor tests have widespread utility in rodent models of TBI and psychopharmacology. Comparatively, behavioral tests for the evaluation of neuropsychiatric symptomatology are rarely employed in animal models of TBI and, as determined in this review, the results have been inconsistent. Animal behavioral studies contribute to the understanding of the biological mechanisms by which TBI is associated with neurobehavioral symptoms and offer a powerful means for pre-clinical treatment validation. Therefore, further exploration of the utility of animal behavioral tests for the study of injury mechanisms and therapeutic strategies for the alleviation of emotional symptoms are relevant and essential. PMID:24109476

Malkesman, Oz; Tucker, Laura B.; Ozl, Jessica; McCabe, Joseph T.

2013-01-01

415

Synthetic cathinones and their rewarding and reinforcing effects in rodents  

PubMed Central

Synthetic cathinones, colloquially referred to as “bath salts”, are derivatives of the psychoactive alkaloid cathinone found in Catha edulis (Khat). Since the mid-to-late 2000’s, these amphetamine-like psychostimulants have gained popularity amongst drug users due to their potency, low cost, ease of procurement, and constantly evolving chemical structures. Concomitant with their increased use is the emergence of a growing collection of case reports of bizarre and dangerous behaviors, toxicity to numerous organ systems, and death. However, scientific information regarding the abuse liability of these drugs has been relatively slower to materialize. Recently we have published several studies demonstrating that laboratory rodents will readily self-administer the “first generation” synthetic cathinones methylenedioxypyrovalerone (MDPV) and methylone via the intravenous route, in patterns similar to those of methamphetamine. Under progressive ratio schedules of reinforcement, the rank order of reinforcing efficacy of these compounds are MDPV ? methamphetamine > methylone. MDPV and methylone, as well as the “second generation” synthetic cathinones ?-pyrrolidinovalerophenone (?-PVP) and 4-methylethcathinone (4-MEC), also dose-dependently increase brain reward function. Collectively, these findings indicate that synthetic cathinones have a high abuse and addiction potential and underscore the need for future assessment of the extent and duration of neurotoxicity induced by these emerging drugs of abuse. PMID:25328910

Watterson, Lucas R.; Olive, M. Foster

2014-01-01

416

Dynamic resting state functional connectivity in awake and anesthetized rodents.  

PubMed

Since its introduction, resting-state functional magnetic resonance imaging (rsfMRI) has been a powerful tool for investigating functional neural networks in both normal and pathological conditions. When measuring resting-state functional connectivity (RSFC), most rsfMRI approaches do not consider its temporal variations and thus only provide the averaged RSFC over the scan time. Recently, there has been a surge of interest to investigate the dynamic characteristics of RSFC in humans, and promising results have been yielded. However, our knowledge regarding the dynamic RSFC in animals remains sparse. In the present study we utilized the single-volume co-activation method to systematically study the dynamic properties of RSFC within the networks of infralimbic cortex (IL) and primary somatosensory cortex (S1) in both awake and anesthetized rats. Our data showed that both IL and S1 networks could be decomposed into several spatially reproducible but temporally changing co-activation patterns (CAPs), suggesting that dynamic RSFC was indeed a characteristic feature in rodents. In addition, we demonstrated that anesthesia profoundly impacted the dynamic RSFC of neural circuits subserving cognitive and emotional functions but had less effects on sensorimotor systems. Finally, we examined the temporal characteristics of each CAP, and found that individual CAPs exhibited consistent temporal evolution patterns. Together, these results suggest that dynamic RSFC might be a general phenomenon in vertebrate animals. In addition, this study has paved the way for further understanding the alterations of dynamic RSFC in animal models of brain disorders. PMID:25315787

Liang, Zhifeng; Liu, Xiao; Zhang, Nanyin

2015-01-01

417

Reproducibility of odor maps by fMRI in rodents.  

PubMed

The interactions of volatile odorants with the approximately 1000 types of olfactory receptor neurons in the olfactory mucosa are represented in the olfactory bulb by glomerular spatial activity maps. If these spatial maps underlie the perceptual identification of odorants then, for a given organism, they must be both specific and reproducible. However, this intra-organism reproducibility need not be present between organisms because genetic and developmental studies of olfactory bulb wiring suggest that there is substantial variation between the glomerular arrangements of closely related organisms and even between the two bulbs in a given animal. The ability of functional MRI (fMRI) to record responses of the entire rodent olfactory bulb repeatedly within the same subject has made it possible to assess the reproducibility of odor-induced spatial activity maps both within and between subjects exposed to equivalent stimuli. For a range of odorants, representing multiple chemical classes, a level of fMRI reproducibility (at 7.0 T and 9.4 T) comparable or superior to other cortical regions was demonstrated. While the responses of different bulbs to the same odorant could be localized within the same broad regions of the glomerular sheet, the precise magnitude and topology of the response within those regions were both often highly variable. These results demonstrate the robustness of high-field fMRI as a tool for assaying olfactory bulb function and provide evidence that equivalent perceptual outcomes may arise from divergent neural substrates. PMID:16632382

Schafer, James R; Kida, Ikuhiro; Xu, Fuqiang; Rothman, Douglas L; Hyder, Fahmeed

2006-07-01

418

Hepatoprotective effect of aged black garlic extract in rodents.  

PubMed

In this study, we investigated the hepatoprotective effects of aged black garlic (ABG) in rodent models of liver injury. ABG inhibited carbon tetrachloride-induced elevation of aspartate transaminase (AST) and alanine transaminase (ALT), which are markers of hepatocellular damage, in SD rats. D-galactosamineinduced hepatocellular damage was also suppressed by ABG treatment. However, ABG does not affect the elevation of alkaline phosphatase (ALP), a marker of hepatobilliary damage, in rats treated with carbon tetrachloride or D-galactosamine. We also examined the effect of ABG on high-fat diet (HFD)-induced fatty liver and subsequent liver damage. ABG had no significant effect on body weight increase and plasma lipid profile in HFD-fed mice. However, HFD-induced increase in AST and ALT, but not ALP, was significantly suppressed by ABG treatment. These results demonstrate that ABG has hepatoprotective effects and suggest that ABG supplementation might be a good adjuvant therapy for the management of liver injury. PMID:24795800

Shin, Jung Hyu; Lee, Chang Woo; Oh, Soo Jin; Yun, Jieun; Kang, Moo Rim; Han, Sang-Bae; Park, Heungsik; Jung, Jae Chul; Chung, Yoon Hoo; Kang, Jong Soon

2014-03-01

419

Electrochemical Techniques for Subsecond Neurotransmitter Detection in Live Rodents  

PubMed Central

Alterations in neurotransmission have been implicated in numerous neurodegenerative and neuropsychiatric disorders, including Alzheimer disease, Parkinson disease, epilepsy, and schizophrenia. Unfortunately, few techniques support the measurement of real-time changes in neurotransmitter levels over multiple days, as is essential for ethologic and pharmacodynamic testing. Microdialysis is commonly used for these research paradigms, but its poor temporal and spatial resolution make this technique inadequate for measuring the rapid dynamics (milliseconds to seconds) of fast signaling neurotransmitters, such as glutamate and acetylcholine. Enzymatic microelectrode arrays (biosensors) coupled with electrochemical recording techniques have demonstrated fast temporal resolution (less than 1 s), excellent spatial resolution (micron-scale), low detection limits (?200 nM), and minimal damage (50 to 100 µm) to surrounding brain tissue. Here we discuss the benefits, methods, and animal welfare considerations of using platinum microelectrodes on a ceramic substrate for enzyme-based electrochemical recording techniques for real-time in vivo neurotransmitter recordings in both anesthetized and awake, freely moving rodents. PMID:25296011

Hascup, Kevin N; Hascup, Erin R

2014-01-01

420

Overshooting convection in tropical cyclones David M. Romps1  

E-print Network

Overshooting convection in tropical cyclones David M. Romps1 and Zhiming Kuang1 Received 20 January imagery, best-track data, and reanalysis data, tropical cyclones are shown to contain a disproportionate amount of the deepest convection in the tropics. Although tropical cyclones account for only 7

Romps, David M.

421

46 CFR 42.30-15 - Tropical Zone.  

Code of Federal Regulations, 2010 CFR

...Southern boundary of the Tropical Zone. The southern boundary of the Tropical Zone is the rhumb line from the Port of Santos, Brazil, to the point where the meridian of longitude 40° W. intersects the Tropic of Capricorn; thence the Tropic of...

2010-10-01

422

46 CFR 42.30-15 - Tropical Zone.  

Code of Federal Regulations, 2013 CFR

...Southern boundary of the Tropical Zone. The southern boundary of the Tropical Zone is the rhumb line from the Port of Santos, Brazil, to the point where the meridian of longitude 40° W. intersects the Tropic of Capricorn; thence the Tropic of...

2013-10-01

423

46 CFR 42.30-15 - Tropical Zone.  

Code of Federal Regulations, 2011 CFR

...Southern boundary of the Tropical Zone. The southern boundary of the Tropical Zone is the rhumb line from the Port of Santos, Brazil, to the point where the meridian of longitude 40° W. intersects the Tropic of Capricorn; thence the Tropic of...

2011-10-01

424

46 CFR 42.30-15 - Tropical Zone.  

Code of Federal Regulations, 2012 CFR

...Southern boundary of the Tropical Zone. The southern boundary of the Tropical Zone is the rhumb line from the Port of Santos, Brazil, to the point where the meridian of longitude 40° W. intersects the Tropic of Capricorn; thence the Tropic of...

2012-10-01

425

WMO/CAS/WWW SEVENTH INTERNATIONAL WORKSHOP ON TROPICAL CYCLONES  

E-print Network

1 WMO/CAS/WWW SEVENTH INTERNATIONAL WORKSHOP ON TROPICAL CYCLONES Topic 2.1: Tropical-Cyclone of tropical-cyclone formation and a potentially useful perspective for forecasters and researchers. The topic of tropical cyclone formation has been the subject of considerable active research in the past four years

Smith, Roger K.

426

The diversity of microparasites of rodents: a comparative analysis that helps in identifying rodent-borne rich habitats in Southeast Asia  

PubMed Central

Background Predicting habitats prone to favor disease transmission is challenging due to confounding information on habitats, reservoirs, and diseases. Comparative analysis, which aims at investigating ecological and evolutionary patterns among species, is a tool that may help. The emergence of zoonotic pathogens is a major health concern and is closely linked to habitat modifications by human activities. Risk assessment requires a better knowledge of the interactions between hosts, parasites, and the landscape. Methods We used information from a field spatial study that investigated the distribution of murid rodents, in various habitats of three countries in Southeast Asia, in combination with their status of infection by 10 taxa of microparasites obtained from the literature. Microparasite species richness was calculated by rodent species on 20,272 rodents of 13 species. Regression tree models and generalized linear models were used to explain microparasite diversity by the average distance between the trapping site and five categories of land cover: forest, steep agriculture land, flat agriculture land, water, and built-up surfaces. Another variable taken into account was the slope. Results We found that microparasite diversity was positively associated with flat agriculture land, in this context mainly rice fields, and negatively associated with slope. Microparasite diversity decreased sharply a 100 m or less from flat agriculture land. Conclusion We conclude that there is high microparasite circulation in rodents of flooded farmlands, meaning possibly a higher risk of disease for human inhabitants. PMID:23577229

Bordes, Frédéric; Herbreteau, Vincent; Dupuy, Stéphane; Chaval, Yannick; Tran, Annelise; Morand, Serge

2013-01-01

427

Variability in subtropical-tropical cells drives oxygen levels in the tropical Pacific Ocean  

NASA Astrophysics Data System (ADS)

studies found a negative trend in oxygen concentrations in tropical regions during the last decades. Employing a biogeochemical circulation model, we highlight the importance of wind-driven ocean transport associated with the Subtropical-Tropical Cells (STCs) in setting the oxygen levels in the tropical ocean. The observed and simulated slowdown of the STCs by 30% from the 1960s to the 1990s caused a decrease in oxygen transport to the tropics. Transport of phosphate was similarly reduced, decreasing export production and respiration. The effects of physical transport and biological consumption partly compensate, damping oxygen interannual and decadal variability. Our results suggest that the observed residual oxygen trend in the tropical Pacific is mainly driven by changes in oxygen transport. Accordingly, the observed recent strengthening of the STCs leads us to expect a pause in the oxygen decrease or even an increase of tropical Pacific oxygen values in the near future.

Duteil, Olaf; Böning, Claus W.; Oschlies, Andreas

2014-12-01

428

Tropical medicine: Telecommunications and technology transfer  

NASA Technical Reports Server (NTRS)

The potential for global outbreaks of tropical infectious diseases, and our ability to identify and respond to such outbreaks is a major concern. Rapid, efficient telecommunications is viewed as part of the solution to this set of problems - the means to link a network of epidemiological field stations via satellite with U.S. academic institutions and government agencies, for purposes of research, training in tropical medicine, and observation of and response to epidemic emergencies. At a workshop, telecommunications and technology transfer were addressed and applications of telecommunications technology in long-distance consultation, teaching and disaster relief were demonstrated. Applications in teaching and consultation in tropical infectious diseases is discussed.

Legters, Llewellyn J.

1991-01-01

429

Linear independence over tropical semirings and beyond  

E-print Network

We investigate different notions of linear independence and of matrix rank that are relevant for max-plus or tropical semirings. The factor rank and tropical rank have already received attention, we compare them with the ranks defined in terms of signed tropical determinants or arising from a notion of linear independence introduced by Gondran and Minoux. To do this, we revisit the symmetrization of the max-plus algebra, establishing properties of linear spaces, linear systems, and matrices over the symmetrized max-plus algebra. In parallel we develop some general technique to prove combinatorial and polynomial identities for matrices over semirings that we illustrate by a number of examples.

Akian, Marianne; Guterman, Alexander

2008-01-01

430

Tropical Pacific Observing for the Next Decade  

NASA Astrophysics Data System (ADS)

More than 60 scientists and program officials from 13 countries met at the Scripps Institution of Oceanography for the Tropical Pacific Observing System (TPOS) 2020 Workshop. The workshop, although motivated in part by the dramatic decline of NOAA's Tropical Atmosphere Ocean (TAO) buoy reporting from mid-2012 to early 2014 (see http://www.bloomberg.com/news/2014-03-07/aging-el-nino-buoys-getting-fixed-as-weather-forecasts-at-risk.html), evaluated the needs for tropical Pacific observing and initiated efforts to develop a more resilient and integrative observing system for the future.

Legler, David M.; Hill, Katherine

2014-06-01

431

Microphysical Characteristics of Tropical Clouds  

NASA Technical Reports Server (NTRS)

This report summarizes the analysis of data collected by the University of North Dakota Citation II measurement platform during three TRMM Field measurement campaigns. The Citation II made cloud measurements during TEFLUN B in Florida, the LBA program in Brazil, and KWAJEX in Kwajalein. The work performed can be divided into two parts. The first part consisted of reformatting the Citation data into a form more easily used to compare to the satellite information. The second part consisted of examination of the cloud data in order to characterize the properties of the tropical clouds. The reformatting of the Citation data was quite labor intensive and, due to the fact that the aircraft was involved in three of the field campaigns, it required a substantial number of person-hours to complete. Much of the analysis done on the second part was done in conjunction with the thesis work of Nicholas Anderson, then a graduate student at the University of North Dakota.

Grainger, Cedric A.; Anderson, Nicholas

2004-01-01

432

Predictability of the tropical atmosphere  

NASA Technical Reports Server (NTRS)

An examination of the deterministic predictability for tropics and middle-latitudes separately indicates that the theoretical upper limit of deterministic predictability for low latitudes is shorter than that for middle latitudes. Variability of time averages in low latitudes is mainly determined by the location and intensity of the large-scale Hadley and Walker circulations. Since these are largely influenced by the slowly varying boundary conditions of sea surface temperature and soil moisture, and since synoptic instabilities are not strong enough to change drastically the large scale flow, there is larger potential for predictability of monthly and seasonal means in low latitudes. It is conjectured that for short and medium range deterministic prediction, a prescribed diabatic heating field due to moist convection may be more useful than their explicit calculation from the evolving flow.

Shukla, J.

1981-01-01

433

Bromoform in the tropical Atlantic  

NASA Astrophysics Data System (ADS)

Sea-to-air emissions of reactive, brominated halocarbons, of which bromoform (CHBr3) is the major organic source for atmospheric reactive bromine, are controlled by biotic and abiotic production and consumption processes in the water. These compounds affect the 'oxidising capacity' of the lower atmosphere, primarily as a result of their influence on the ozone concentration. Besides a large macroalgal source in coastal regions, oversaturation in the worlds open oceans contributes significantly to the global emissions, suggesting an yet unknown open ocean source. Atmospheric studies in the Pacific and Atlantic have revealed maxima of tropospheric bromoform concentrations in equatorial regions, suggesting enhanced surface sources in these waters. The responsible processes and fluxes in the open ocean are generally poorly characterised. A west to east transect along 10°N including a short meridional transect into the equatorial upwelling was conducted in the tropical Atlantic Ocean from Curacao to Doualla with R/V Meteor in October /November 2002 (ME55). Surface samples and samples from shallow hydro casts (<500 m) were analysed on board for the brominated compounds dibromomethane (CH2Br2), dibromochloromethane (CHBr2Cl), dichlorobromomethane (CHBrCl2) and bromoform (CHBr3), using purge-and-trap gas chromatography with mass spectrometry. Preliminary results for bromoform show background concentrations of 2-4 pmol/L in the surface ocean and 1-2 pmol/L in deeper layers. Elevated concentrations of 8 to 14 pmol/L bromoform were observed in the area of equatorial upwelling. Maxima up to 30 pmol/L bromoform were always found underneath the mixed layer and seem to be associated with the chlorophyll maximum in 40 to 70 m depth. The highest concentrations of CHBr3 (2nmol/L) as well as of CHBr2Cl, CHBrCl2 and CHCl3 were discovered in the Amazone river plume at the boundary between the river and ocean waters around 40 m depth. Ancillary profile data such as productivity, chlorophyll a and other pigments, species composition, dissolved organic carbon (DOC), particulate organic carbon (POC), oxygen, nutrients (N,P,Si) and hydrogenperoxide (H2O2) are available. Correlations with the halocarbon data will be evaluated in the near future, which may help to understand the deep maximum of bromoform and determine sources of the brominated methanes. Air samples were taken and concentrations of the halocarbons will be analysed by the groups of Elliot Atlas (NCAR, Boulder) and James H. Butler (NOAA, Boulder) to reveal the saturation-anomalies and the air-sea fluxes of the compounds from the tropical oceanic surface waters. Preliminary results of our measurements show background concentrations of bromoform below 1 ppt , which make the tropical ocean waters a general source of this compound for the atmosphere. In the following months we will incorporated the air-sea fluxes, photochemical data (JNO2) and bromine oxide (BrO), obtained during the cruise in an atmospheric model, to investigate the contribution of tropical bromofrom and other compounds to the atmospheric reactive bromine budget.

Quack, B.; Wallace, D.

2003-04-01

434

Sperm Competition, Sperm Numbers and Sperm Quality in Muroid Rodents  

PubMed Central

Sperm competition favors increases in relative testes mass and production efficiency, and changes in sperm phenotype that result in faster swimming speeds. However, little is known about its effects on traits that contribute to determine the quality of a whole ejaculate (i.e., proportion of motile, viable, morphologically normal and acrosome intact sperm) and that are key determinants of fertilization success. Two competing hypotheses lead to alternative predictions: (a) sperm quantity and quality traits co-evolve under sperm competition because they play complementary roles in determining ejaculate's competitive ability, or (b) energetic constraints force trade-offs between traits depending on their relevance in providing a competitive advantage. We examined relationships between sperm competition levels, sperm quantity, and traits that determine ejaculate quality, in a comparative study of 18 rodent species using phylogenetically controlled analyses. Total sperm numbers were positively correlated to proportions of normal sperm, acrosome integrity and motile sperm; the latter three were also significantly related among themselves, suggesting no trade-offs between traits. In addition, testes mass corrected for body mass (i.e., relative testes mass), showed a strong association with sperm numbers, and positive significant associations with all sperm traits that determine ejaculate quality with the exception of live sperm. An “overall sperm quality” parameter obtained by principal component analysis (which explained 85% of the variance) was more strongly associated with relative testes mass than any individual quality trait. Overall sperm quality was as strongly associated with relative testes mass as sperm numbers. Thus, sperm quality traits improve under sperm competition in an integrated manner suggesting that a combination of all traits is what makes ejaculates more competitive. In evolutionary terms this implies that a complex network of genetic and developmental pathways underlying processes of sperm formation, maturation, transport in the female reproductive tract, and preparation for fertilization must all evolve in concert. PMID:21464956

Gómez Montoto, Laura; Magaña, Concepción; Tourmente, Maximiliano; Martín-Coello, Juan; Crespo, Cristina; Luque-Larena, Juan José

2011-01-01

435

Ventilatory accommodation of changing oxygen demand in sciurid rodents.  

PubMed

Ventilation was measured across a range of O2 consumption rates in four sciurid rodents: Tamias minimus (47 g), Spermophilus lateralis (189 g), S. beecheyi (531 g), and Marmota flaviventris juveniles (1054 g) and adults (2989 g). Maximum thermogenic oxygen consumption was measured for all but adult M. flaviventris. Aerobic scopes (maximum/minimum O2 consumption rates) were 4.6, 3.8, 5.4, and 4.8 in T. minimus, S. lateralis, S. beecheyi, and juvenile M. flaviventris, respectively. Aerobic scope was at least 4.1 in adult M. flaviventris. Ventilatory accommodation of changing O2 consumption rate was qualitatively similar in the four species, with the bulk of accommodation resulting from changes in minute volume. Nevertheless, there were significant differences in the relative importance of frequency, tidal volume, and O2 extraction in accommodation. In all species, frequency and minute volume were strongly correlated to O2 consumption rate. Tidal volume was significantly correlated to O2 consumption rate in T. minimus and S. beecheyi, but not in the other species. Oxygen extraction was not significantly correlated to O2 consumption rate in any species. Analysis of factorial ventilation changes across a standardized 3.8-fold change in O2 consumption rate revealed significant differences among species in frequency and O2 extraction, but not in tidal or minute volume. When compared to a generalized allometry for mammalian resting ventilation, the four sciurid species had consistently lower respiration frequency and higher O2 extraction than predicted, perhaps because the sciurid measurements were made on unrestrained animals. There was no indication that ventilation constrained maximum O2 consumption rate. PMID:1494030

Chappell, M A

1992-01-01

436

Lung imaging in rodents using dual energy micro-CT  

NASA Astrophysics Data System (ADS)

Dual energy CT imaging is expected to play a major role in the diagnostic arena as it provides material decomposition on an elemental basis. The purpose of this work is to investigate the use of dual energy micro-CT for the estimation of vascular, tissue, and air fractions in rodent lungs using a post-reconstruction three-material decomposition method. We have tested our method using both simulations and experimental work. Using simulations, we have estimated the accuracy limits of the decomposition for realistic micro-CT noise levels. Next, we performed experiments involving ex vivo lung imaging in which intact lungs were carefully removed from the thorax, were injected with an iodine-based contrast agent and inflated with air at different volume levels. Finally, we performed in vivo imaging studies in (n=5) C57BL/6 mice using fast prospective respiratory gating in endinspiration and end-expiration for three different levels of positive end-expiratory pressure (PEEP). Prior to imaging, mice were injected with a liposomal blood pool contrast agent. The mean accuracy values were for Air (95.5%), Blood (96%), and Tissue (92.4%). The absolute accuracy in determining all fraction materials was 94.6%. The minimum difference that we could detect in material fractions was 15%. As expected, an increase in PEEP levels for the living mouse resulted in statistically significant increases in air fractions at end-expiration, but no significant changes in end-inspiration. Our method has applicability in preclinical pulmonary studies where various physiological changes can occur as a result of genetic changes, lung disease, or drug effects.

Badea, C. T.; Guo, X.; Clark, D.; Johnston, S. M.; Marshall, C.; Piantadosi, C.

2012-03-01

437

Dynamics of INSL3 peptide expression in the rodent testis.  

PubMed

The Leydig cell-specific factor insulin-like peptide 3 (INSL3) is involved in testicular descent during embryo development, and has been suggested to regulate spermatogenesis and bone metabolism in the adult. Using a new, sensitive assay specific for rodent INSL3, we have mapped the secretion of INSL3 into peripheral blood in mice and during postnatal male rat development (in female rats, circulating INSL3 is at the level of detection). Maximum INSL3 is measured at Postnatal Day (PD) 40 in the rat and decreases to a significantly lower, stable value by PD60, indicating an "overshoot" effect in the establishment of Leydig cell functionality during the first wave of spermatogenesis. Aging rats ( approximately 24 mo) have markedly reduced circulating INSL3 levels, as do humans. Treatment of young adult rats with ethane dimethylsulfonate (EDS) leads to loss of mature Leydig cells and no detectable INSL3 in peripheral blood. INSL3 can be detected first at Day 27 after EDS treatment, returning to near normal levels by Day 37. Both primary rat Leydig cells and the mouse MA-10 tumor cell line secrete substantial amounts of INSL3 into the culture media in a constitutive manner, unregulated by common effectors, including hCG. Analysis of different testicular fluid compartments shows highest INSL3 concentration in the interstitial fluid (391.4 +/- 47.8 ng/ml). However, INSL3 evidently traverses the blood-testis barrier to enter the seminiferous compartment, rete testis, and epididymis in sufficient concentration to be able to address the specific INSL3 receptors (RXFP2) on post-meiotic germ cells and in the epididymis. PMID:19420383

Anand-Ivell, Ravinder; Heng, Kee; Hafen, Bettina; Setchell, Brian; Ivell, Richard

2009-09-01

438

Stress induced obesity: lessons from rodent models of stress  

PubMed Central

Stress was once defined as the non-specific result of the body to any demand or challenge to homeostasis. A more current view of stress is the behavioral and physiological responses generated in the face of, or in anticipation of, a perceived threat. The stress response involves activation of the sympathetic nervous system and recruitment of the hypothalamic-pituitary-adrenal (HPA) axis. When an organism encounters a stressor (social, physical, etc.), these endogenous stress systems are stimulated in order to generate a fight-or-flight response, and manage the stressful situation. As such, an organism is forced to liberate energy resources in attempt to meet the energetic demands posed by the stressor. A change in the energy homeostatic balance is thus required to exploit an appropriate resource and deliver useable energy to the target muscles and tissues involved in the stress response. Acutely, this change in energy homeostasis and the liberation of energy is considered advantageous, as it is required for the survival of the organism. However, when an organism is subjected to a prolonged stressor, as is the case during chronic stress, a continuous irregularity in energy homeostasis is considered detrimental and may lead to the development of metabolic disturbances such as cardiovascular disease, type II diabetes mellitus and obesity. This concept has been studied extensively using animal models, and the neurobiological underpinnings of stress induced metabolic disorders are beginning to surface. However, different animal models of stress continue to produce divergent metabolic phenotypes wherein some animals become anorexic and lose body mass while others increase food intake and body mass and become vulnerable to the development of metabolic disturbances. It remains unclear exactly what factors associated with stress models can be used to predict the metabolic outcome of the organism. This review will explore a variety of rodent stress models and discuss the elements that influence the metabolic outcome in order to further extend our understanding of stress-induced obesity. PMID:23898237

Patterson, Zachary R.; Abizaid, Alfonso

2013-01-01

439

Rodent neurotoxicity bioassays for screening contaminated Great Lakes fish  

SciTech Connect

Standard laboratory rat neurotoxicity protocols were used to study the consequences resulting from the consumption of walleye (Stizostedion vitreum), whitefish (Coregonus clupeaformis), and lake trout (Salvelinus namaycush) from Lake Superior (LS) and the consumption of carp (Cyprinus carpio) from Little Lake Butte des Morte (LLBM) near Oshkosh, Wisconsin, USA. Two 90-d subchronic studies are described, including a 45-d exposure to fish diets using male Sprague-Dawley hooded rats, and a 90-d exposure to fish diets using female rats of the same species. Behavioral alterations were tested using a battery of behavioral tests. In addition, pharmacologic challenges using apomorphine and D-amphetamine were administered to the rats to reveal latent neurotoxic effects. Cumulative fish consumption data were recorded daily, weight gain recorded weekly, and behavior data collected prior to exposure, and on days 7, 14, 55 {+-} 2, 85 {+-} 2. Motor activity data were collected on days 30 {+-} 2, 60 {+-} 2, and 90 {+-} 2 of the feeding protocols. Brain tissue from rodents fed these fish were subsequently analyzed for either mercury (Hg) or polychlorinated biphenyls (PCB). Mercury concentrations were increased in the brains of the walleye-fed rats, and PCB concentrations ranged from 0.5 nl/L to 10 nl/L in the brains of rats fed carp from LLBM, a Lake Michigan tributary. Adult male rats fed LLBM carp for 45 d exhibited the greatest behavior responses to the dopaminergic agonist apomorphine on the accelerating rotarod, although these differences were not significant. The 90-d exposure of LS walleye or Hg-spiked LS walleye resulted in behavior alterations on tactile startle response and second footsplay. D-Amphetamine challenge caused changes in tactile startle response, second footsplay, and accelerating rotarod performance after consuming walleye diets. Rats fed LLBM carp had altered behavioral responses to apomorphine on the accelerating rotarod.

Beattie, M.K.; Hoffman, R. [Univ. of Minnesota, Duluth, MN (United States); Gerstenberger, S. [Univ. of Illinois, Urbana, IL (United States). Dept. of Veterinary Biosciences; Dellinger, J.A. [Medical Coll. of Wisconsin, Milwaukee, MI (United States). Dept. of Preventive Medicine

1996-03-01

440

NASA Rodent Foodbar: Long Term Effects in Swiss Webster Mice  

NASA Technical Reports Server (NTRS)

Swiss Webster male and female mice (150 of each) were fed NASA Rodent Foodbar for more than 110 days to test the diet's nutritional adequacy for use in future long-term studies aboard the International Space Station. Mice were grouped three to a cage (one cage = one sample) and cages were assigned to either Foodbar or Purina Chow #5001 (control) diet groups. Body weights, food intake, and water intake were obtained throughout the study. There were no significant differences in body weights between male Foodbar fed and Chow fed males (p=0.58), and at 15 weeks into the female mouse study there appear to be no significant body weight differences. Both male and female Foodbar fed groups consumed more food and less water than their Chow controls, both factors thought to be attributable to the high moisture content of the Foodbars (26% versus 10% for Chow). All differences in gross food and water consumption had p-values of less than 0.01. When food and water intake were adjusted for the moisture content in the food, both male and female Foodbar fed animals consumed less food, but still had a lower water intake rate than their controls. (p is less than 0.01). Preliminary analysis on blood samples from male and female halfway point dissections suggests differences in glucose and fat metabolism. In both male and female Foodbar fed animals, blood glucose values were significantly lower (p is less than 0.01) but there were no significant differences in cholesterol levels (p=0.51). In Foodbar fed females, triglycerides were significantly higher (p is less than 0.01). These data suggest that Foodbars allow for normal growth in Swiss Webster mice, but affect some blood chemistry parameters.

Santiago, D. L.; Yu, D. S.; Naficy, N. H.; Roghani, P. M.; Dalton, B. P.; Barrett, J. E.; Dalton, Bonnie (Technical Monitor)

2001-01-01

441

Lung Function Measurements in Rodents in Safety Pharmacology Studies  

PubMed Central

The ICH guideline S7A requires safety pharmacology tests including measurements of pulmonary function. In the first step – as part of the “core battery” – lung function tests in conscious animals are requested. If potential adverse effects raise concern for human safety, these should be explored in a second step as a “follow-up study”. For these two stages of safety pharmacology testing, both non-invasive and invasive techniques are needed which should be as precise and reliable as possible. A short overview of typical in vivo measurement techniques is given, their advantages and disadvantages are discussed and out of these the non-invasive head-out body plethysmography and the invasive but repeatable body plethysmography in orotracheally intubated rodents are presented in detail. For validation purposes the changes in the respective parameters such as tidal midexpiratory flow (EF50) or lung resistance have been recorded in the same animals in typical bronchoconstriction models and compared. In addition, the technique of head-out body plethysmography has been shown to be useful to measure lung function in juvenile rats starting from day two of age. This allows safety pharmacology testing and toxicological studies in juvenile animals as a model for the young developing organism as requested by the regulatory authorities (e.g., EMEA Guideline 1/2008). It is concluded that both invasive and non-invasive pulmonary function tests are capable of detecting effects and alterations on the respiratory system with different selectivity and area of operation. The use of both techniques in a large number of studies in mice and rats in the last years have demonstrated that they provide useful and reliable information on pulmonary mechanics in safety pharmacology and toxicology testing, in investigations of respiratory disorders, and in pharmacological efficacy studies. PMID:22973226

Hoymann, Heinz Gerd

2012-01-01

442

Rodent models for the study of articular fracture healing.  

PubMed

The goal of this study was to document the healing time course and expression of ex vivo cell-based gene delivery in articular fracture models in the mouse and rat. Articular medial intercondylar femoral osteotomy was performed in the stifle (knee) joints of hairless immunocompetent mice and medial or lateral similar osteotomy was performed in athymic nude rats. Genetically modified cells expressing luciferase were delivered in a three-dimensional alginate matrix directly into the osteotomy site. Sensitivity of an in vivo imaging system to detect expression of luciferase was compared between rodents in this fracture model. Osteotomy healing was assessed using high-detail radiography, helical computed tomography (CT), high-field magnetic resonance imaging, and histology. The mouse model was less satisfactory because the small size of the murine femur made reliable assessment of fracture healing restricted to histopathology, and complications occurred in 11/24 mice (45.8%), most frequently transverse supracondylar femoral fracture postoperatively. Gene expression was inconsistently confirmed in mice in vivo for 11 days (p < .003). In rats, high-detail radiography and CT were used to assess osteotomy healing. Magnetic resonance imaging (4.7 T) in rats could produce three-dimensional images that would permit assessment of bone and cartilage, but was time-consuming and expensive. In rats, the only surgical complication, transverse femoral fracture, was reduced from 83.3% with the medial osteotomy to 0% with a lateral osteotomy. In vivo imaging confirmed gene expression in the alginate/cell constructs in rats for at least 4 days (p < .05). The nude rat model has the advantage of larger femora and the ability to implant xenograft cells. A lateral intercondylar osteotomy of the distal femur in the rat can be used to study the healing of articular fractures. PMID:17454393

Zachos, Terri A; Bertone, Alicia L; Wassenaar, Peter A; Weisbrode, Steven E

2007-01-01

443

Buffering and plasticity in vital rates of oldfield rodents.  

PubMed

1. Under the hypothesis of environmental buffering, populations are expected to minimize the variance of the most influential vital rates; however, this may not be a universal principle. Species with a life span <1 year may be less likely to exhibit buffering because of temporal or seasonal variability in vital rate sensitivities. Further, plasticity in vital rates may be adaptive for species in a variable environment with reliable cues. 2. We tested for environmental buffering and plasticity in vital rates using stage-structured matrix models from long-term data sets in four species of grassland rodents. We used periodic matrices to estimate stochastic elasticity for each vital rate and then tested for correlations with a standardized coefficient of variation for each rate. 3. We calculated stochastic elasticities for individual months to test for an association between increased reproduction and the influence of reproduction, relative to survival, on the population growth rate. 4. All species showed some evidence of buffering. The elasticity of vital rates of Peromyscus leucopus (Rafinesque, 1818), Sigmodon hispidus Say & Ord, 1825 and Microtus ochrogaster (Wagner, 1842) was negatively related to vital rate CV. Elasticity and vital rate CV were negatively related in Peromyscus maniculatus (Wagner, 1845), but the relationship was not statistically significant. Peromyscus leucopus and M. ochrogaster showed plasticity in vital rates; reproduction was higher following months where elasticity for reproduction exceeded that of survival. 5. Our results suggest that buffering is common in species with fast life histories; however, some populations that exhibit buffering are capable of responding to short-term variability in environmental conditions through reproductive plasticity. PMID:22375923

Reed, Aaron W; Slade, Norman A

2012-09-01

444

High abundant protein removal from rodent blood for biomarker discovery.  

PubMed

In order to realize the goal of stratified and/or personalized medicine in the clinic, significant advances in the field of biomarker discovery are necessary. Adding to the abundance of nucleic acid biomarkers being characterized, additional protein biomarkers will be needed to satisfy diverse clinical needs. An appropriate source for finding these biomarkers is within blood, as it contains tissue leakage factors as well as additional proteins that reside in blood that can be linked to the presence of disease. Unfortunately, high abundant proteins and complexity of the blood proteome present significant challenges for the discovery of protein biomarkers from blood. Animal models often enable the discovery of biomarkers that can later be translated to humans. Therefore, determining appropriate sample preparation of proteomic samples in rodent models is an important research goal. Here, we examined both mouse and rat blood samples (including both serum and plasma), for appropriate high abundant protein removal techniques for subsequent gel-based proteomic experiments. We assessed four methods of albumin removal: antibody-based affinity chromatography (MARS), Cibacron® Blue-based affinity depletion (SwellGel® Blue Albumin Removal Kit), protein-based affinity depletion (ProteaPrep Albumin Depletion Kit) and TCA/acetone precipitation. Albumin removal was quantified for each method and SDS-PAGE and 2-DE gels were used to quantify the number of protein spots obtained following albumin removal. Our results suggest that while all four approaches can effectively remove high abundant proteins, antibody-based affinity chromatography is superior to the other three methods. PMID:25445603

Haudenschild, Dominik R; Eldridge, Angela; Lein, Pamela J; Chromy, Brett A

2014-10-24

445

Modeling susceptible infective recovered dynamics and plague persistence in California rodent-flea communities.  

PubMed

Plague persists as an enzootic in several very different rodent-flea communities around the world. In California, a diversity of rodent-flea communities maintains the disease, and a single-host reservoir seems unlikely. Logistic regression of plague presence on climate and topographic variables predicts plague in many localities where it is absent. Thus, a dynamic community-based analysis was needed. Deterministic Susceptible Infective Recovered (SIR) models were adapted for plague and analyzed with an eye for insights concerning disease persistence. An R simulation program, Plaguesirs, was developed incorporating multihost and multivector SIR dynamics, demographic and environmental stochasticity, density dependence, and seasonal variation in birth and death. Flea-rodent utilization matrices allowed us to get transmission rates as well as flea carrying capacities. Rodent densities allowed us to estimate host carrying capacities, while maximum birth rates were mainly approximated through an examination of litter phenology and demography. We ran a set of simulations to assess the role of community structure in maintaining plague in a simulated version of Chuchupate campground in Ventura County. Although the actual campground comprises 10 rodent and 19 flea species, we focused on a subset suspected to act as a reservoir community. This included the vole Microtus californicus, the deer mouse Peromyscus maniculatus, the Ceratophyllid fleas Aetheca wagneri and Malareus telchinum, and the Leptopsyllid flea Peromyscopsylla hesperomys. The dynamics of 21 subsets of this community were simulated for 20 years. Single-rodent communities showed much lower disease persistence than two-rodent communities. However, so long as Malareus was present, endemicity was enhanced; removal of the other two fleas slightly increased disease persistence. Two critical features improved disease persistence: (1) host breeding season heterogeneity and (2) host population augmentation (due to two similar host species instead of one). Voles are winter-spring breeders compared to the spring-summer deer mice. While host synchronicity may enhance epidemics, host asynchronicity favors endemics. PMID:20158333

Foley, Patrick; Foley, Janet

2010-01-01

446

Prevalence and Genetic Diversity of Bartonella Species Isolated from Wild Rodents in Japan?  

PubMed Central

Here, we describe for the first time the prevalence and genetic properties of Bartonella organisms in wild rodents in Japan. We captured 685 wild rodents throughout Japan (in 12 prefectures) and successfully isolated Bartonella organisms from 176 of the 685 rodents (isolation rate, 25.7%). Those Bartonella isolates were all obtained from the rodents captured in suburban areas (rate, 51.8%), but no organism was isolated from the animals captured in city areas. Sequence analysis of rpoB and gltA revealed that the Bartonella isolates obtained were classified into eight genetic groups, comprising isolates closely related to B. grahamii (A-I group), B. tribocorum and B. elizabethae (B-J group), B. tribocorum and B. rattimassiliensis (C-K group), B. rattimassiliensis (D-L group), B. phoceensis (F-N group), B. taylorii (G-O group), and probably two additional novel Bartonella species groups (E-M and H-P). B. grahamii, which is one of the potential causative agents of human neuroretinitis, was found to be predominant in Japanese rodents. In terms of the relationships between these Bartonella genetic groups and their rodent species, (i) the A-I, E-M, and H-P groups appear to be associated with Apodemus speciosus and Apodemus argenteus; (ii) the C-K, D-L, and F-N groups are likely implicated in Rattus rattus; (iii) the B-J group seems to be involved in Apodemus mice and R. rattus; and (iv) the G-O group is probably associated with A. speciosus and Clethrionomys voles. Furthermore, dual infections with two different genetic groups of bartonellae were found in A. speciosus and R. rattus. These findings suggest that the rodent in Japan might serve as a reservoir of zoonotic Bartonella infection. PMID:18606803

Inoue, Kai; Maruyama, Soichi; Kabeya, Hidenori; Yamada, Naoyuki; Ohashi, Norio; Sato, Yukita; Yukawa, Masayoshi; Masuzawa, Toshiyuki; Kawamori, Fumihiko; Kadosaka, Teruki; Takada, Nobuhiro; Fujita, Hiromi; Kawabata, Hiroki

2008-01-01

447

Declines in large wildlife increase landscape-level prevalence of rodent-borne disease in Africa  

PubMed Central

Populations of large wildlife are declining on local and global scales. The impacts of this pulse of size-selective defaunation include cascading changes to smaller animals, particularly rodents, and alteration of many ecosystem processes and services, potentially involving changes to prevalence and transmission of zoonotic disease. Understanding linkages between biodiversity loss and zoonotic disease is important for both public health and nature conservation programs, and has been a source of much recent scientific debate. In the case of rodent-borne zoonoses, there is strong conceptual support, but limited empirical evidence, for the hypothesis that defaunation, the loss of large wildlife, increases zoonotic disease risk by directly or indirectly releasing controls on rodent density. We tested this hypothesis by experimentally excluding large wildlife from a savanna ecosystem in East Africa, and examining changes in prevalence and abundance of Bartonella spp. infection in rodents and their flea vectors. We found no effect of wildlife removal on per capita prevalence of Bartonella infection in either rodents or fleas. However, because rodent and, consequently, flea abundance doubled following experimental defaunation, the density of infected hosts and infected fleas was roughly twofold higher in sites where large wildlife was absent. Thus, defaunation represents an elevated risk in Bartonella transmission to humans (bartonellosis). Our results (i) provide experimental evidence of large wildlife defaunation increasing landscape-level disease prevalence, (ii) highlight the importance of susceptible host regulation pathways and host/vector density responses in biodiversity–disease relationships, and (iii) suggest that rodent-borne disease responses to large wildlife loss may represent an important context where this relationship is largely negative. PMID:24778215

Young, Hillary S.; Dirzo, Rodolfo; Helgen, Kristofer M.; McCauley, Douglas J.; Kosoy, Michael Y.; Osikowicz, Lynn M.; Salkeld, Daniel J.; Young, Truman P.; Dittmar, Katharina

2014-01-01

448

Moss species benefits from breakdown of cyclic rodent dynamics in boreal forests.  

PubMed

Bryophytes have increased in abundance in northern regions, and climate changes have been proposed to account for this change. However, changes in the population dynamics of microtine rodents may also contribute to changes in bryophyte abundance. New evidence indicates a tendency for microtine rodent population oscillations to change from periodicity of 3-5 years to become irregular or acyclic. The impact on ecosystem functioning is potentially great. We study the impact of variation in microtine rodent population characteristics, such as cycle length and amplitude, on the population dynamics of the boreal, clonal moss Hylocomium splendens. We use experimental and observational demographic data to construct 127 scenarios representing all combinations of disturbance type (gap formation and/or clipping), period (cyclic with 4, 6, 12, or 24 years between rodent peaks; or acyclic with constant or stochastically varying annual disturbance severity) and disturbance severity (fraction of individuals affected by disturbance in each year relative to the maximum disturbance carried out in the field experiment; seven levels). Population data collected in the field during 13 years were used as a baseline scenario. By subjecting all scenarios to stochastic matrix modeling, we demonstrate considerable impact of microtine rodent on the population dynamics of H. splendens, most notably when rodent populations fluctuate with short periods and high peak disturbance severities. Under the same average disturbance severity, H. splendens population growth rates are highest in acyclic scenarios and are progressively reduced with increasing peak disturbance severities (i.e., with increasing period). Stochastic elasticity analyses show that in less variable environments mature segment survival contributes more to the population growth rate, while in more variable environments the regeneration pathway (branching of older parts of the plant) plays a stronger role, inevitably leading to lower population fitness. Our results support the hypothesis that breakdown of cyclic rodent population dynamics accentuates increase in the abundance of H. splendens and other large bryophytes in boreal forests in Norway, observed empirically in recent years and primarily ascribed to climatic change. PMID:17918409

Rydgren, Knut; Økland, Rune H; Picó, F Xavier; de Kroon, Hans

2007-09-01

449

Neogene paleobiogeography and East African paleoenvironments: contributions from the Tugen Hills rodents and lagomorphs.  

PubMed

A minimum of 28 genera of rodents and one genus of lagomorph were recovered from the Tugen Hills, Baringo District, Kenya, from localities dating from over 15.5 to about 4.4 Ma. The middle Miocene (sites dated between 15.8 and 15.3 Ma) rodent fauna recovered primarily from the Kipsaramon site complex, Muruyur Formation, includes a mixture of characteristically early Miocene taxa, and more derived forms. Composition of the African rodent fauna changes dramatically with the introduction of myocricetodontines, democricetodontines, and dendromurines, immigrants primarily from southern Asia. In the Tugen Hills, these taxa are first found in the Kabasero localities, Ngorora Formation, at sites dating from 12.5-12.33 Ma. A second major change in the African rodent fauna reflects the introduction of murines, immigrants from southern Asia. In the Tugen Hills murines are first encountered at Kapcheberek, Lukeino Formation, dated to 5.9-5.7 Ma. One rodent genus from the Lukeino Formation (Arvicanthis), and two from the Tabarin locality, Chemeron Formation (Heliosciurus, Paraxerus; 4.5-4.4 Ma), represent the earliest records of these extant African genera. A cricetomyine from the Ngorora Formation (12.5 Ma) is likely the earliest report of this exclusively African group. One of the earliest African records of porcupines (Hystricide) is from the Lukeino Formation. Lagomorphs are poorly represented, but include one of the earliest African occurrences of the family Leporidae from the Mpesida Beds (bracketed by dates of 7-6.2 Ma), and possibly a new genus of leporid from the Kapcheberek locality. Analysis of the Tugen Hills small mammals in association with other African records suggests several episodes of dispersal between Africa and Eurasia during the middle and late Miocene. Rodents from Kipsaramon are indicative of forests in conjunction with more open habitats. Those from the Kapcheberek locality are suggestive of a savanna habitat. The rodents from the Tabarin locality suggest a woodland environment. PMID:11795976

Winkler, Alisa J

2002-01-01

450

Multimodality Rodent Imaging Chambers for Use Under Barrier Conditions With Gas Anesthesia  

PubMed Central

Purpose The ability to reproducibly and repeatedly image rodents in non-invasive imaging systems, such as small animal PET and CT, requires a reliable method for anesthetizing, positioning, and heating animals in a simple reproducible manner. In this paper we demonstrate that mice and rats can be reproducibly and repeatedly imaged using an imaging chamber designed to be rigidly mounted on multiple imaging systems. Procedures Mouse and rat imaging chambers were made of acrylic plastic and aluminum. MicroCT scans were used to evaluate the positioning reproducibility of the chambers in multi-modality and longitudinal imaging studies. The ability of the chambers to maintain mouse and rat body temperatures while anesthetized with gas anesthesia was also evaluated. Results Both the mouse and rat imaging chambers were able to reproducibly position the animals in the imaging systems with a small degree of error. Placement of the mouse in the mouse imaging chamber resulted in a mean distance of 0.23 mm per reference point in multimodality studies, whereas for longitudinal studies the mean difference was 1.11 mm. The rat chamber resulted in a mean difference of 0.46 mm in multimodality studies, and a mean difference of 4.31 mm in longitudinal studies per reference point. The chambers maintained rodent body temperatures at the set point temperature of 38°C. Conclusions The rodent imaging chambers were able to reproducibly position rodents in tomographs with a small degree of variability, and were compatible with routine use. The embedded anesthetic line and heating system was capable of maintaining the rodent’s temperature and anesthetic state, thereby enhancing rodent health and improving data collection reliability. PMID:18679755

Suckow, Chris; Kuntner, Claudia; Chow, Patrick; Silverman, Robert; Chatziioannou, Arion; Stout, David

2009-01-01

451

Factors determining the abundance and distribution of rodents in a shrub-steppe ecosystem: the role of shrubs  

Microsoft Academic Search

This study addressed the relative importances of shrub “resources” on a rodent community in a sagebrush dominated shrub-steppe ecosystem in southwestern Wyoming. Direct effects of shrubs (i.e., providing rodents with “food and cover”) were assessed by removing shrubs from a 1.25 ha study plot and monitoring both rodent populations and their food resources. Shrub architecture and shrub-related food resources were

Robert R. Parmenter; James A. MacMahon

1983-01-01

452

Evolutional and Geographical Relationships of Bartonella grahamii Isolates from Wild Rodents by Multi-locus Sequencing Analysis  

Microsoft Academic Search

To clarify the relationship between Bartonella grahamii strains and both the rodent host species and the geographic location of the rodent habitat, we have investigated 31 B. grahamii strains from ten rodent host species from Asia (Japan and China), North America (Canada and the USA), and Europe (Russia\\u000a and the UK). On the basis of multi-locus sequencing analysis of 16S

Kai Inoue; Hidenori Kabeya; Michael Y. Kosoy; Ying Bai; George Smirnov; Dorothy McColl; Harvey Artsob; Soichi Maruyama

2009-01-01

453

Do changes in dietary chemistry during ontogeny affect digestive performance in adults of the herbivorous rodent Octodon degus? .  

E-print Network

??We characterize the flexibility in digestive performance in degus (Octodon degus) an herbivorous rodent. We tested the hypothesis that dietary and physiological-digestive flexibility are correlated.… (more)

Sabat, Pablo

2008-01-01

454

Tropical Storm Don - Duration: 0:31.  

NASA Video Gallery

GOES-13 data was compiled into an animation by the NASA GOES Project at NASA Goddard that shows the development of Tropical Storm Don in the southern Gulf of Mexico, west of Cuba. The animation run...

455

Perspective Climate change and the tropical Pacific  

E-print Network

Perspective Climate change and the tropical Pacific: The sleeping dragon wakes R. T. Pierrehumbert is unsettling in a world seem- ingly committed to substantial warming from anthropogenic CO2 increases

Pierrehumbert, Raymond

456

Tropical Deforestation in the Bolivian Amazon  

NASA Technical Reports Server (NTRS)

Landsat satellite images from the mid-1980s and early 1990s were used to map tropical forest extent and deforestation in approximately 800,000 sq km of Amazonian Bolivia. Forest cover extent, including tropical deciduous forest, totalled 472,000 sq km while the area of natural non-forest formations totalled 298,000 sq km. The area deforested totalled 15,000 sq km in the middle 1980s and 28,800 sq km by the early 1990s. The rate of tropical deforestation in the >1,000 mm/y precipitation forest zone of Bolivia was 2,200 sq km/y from 1985-1986 to 1992-1994. We document a spatially-concentrated "deforestation zone" in Santa Cruz Department where >60% of the Bolivian deforestation is occurring at an accelerating rate in areas of tropical deciduous dry forest.

Tucker, Compton J.; Steininger, Marc K.; Townshend, John R. G.; Killeen, Timothy R.; Desch, Arthur

2000-01-01

457

Tropical gradient influences on Caribbean rainfall  

Microsoft Academic Search

Interbasin and intrabasin gradients are important for Caribbean climateThe tropical gradients, the AWP, and the CLLJ modulate Caribbean rainfall variabilityFuture Caribbean drying is linked to a perpetuating midsummer rainfall minimum

Michael A. Taylor; Tannecia S. Stephenson; Albert Owino; A. Anthony Chen; Jayaka D. Campbell

2011-01-01

458

Tropical Corallimorpharia (Coelenterata: Anthozoa): feeding by envelopment  

E-print Network

Three species of tropical Australian corallimorpharians (family Actinodiscidae) lacking ectodermal nematocysts in their discal tentacles feed by entrapping prey with their oral discs. The largest species can close in three ...

Hamner, William M.; Fautin, Daphne G.

1980-06-01

459

Tropical Storm Faxai - Duration: 0:13.  

NASA Video Gallery

NASA/JAXA's TRMM Satellite provided data of developing Tropical Storm Faxai to make this 3-D image that showed some towering thunderstorms in the area were reaching altitudes of up to 15.5km/~9.6 m...

460

Midlevel ventilation's constraint on tropical cyclone intensity  

E-print Network

Midlevel ventilation, or the flux of low-entropy air into the inner core of a tropical cyclone (TC), is a hypothesized mechanism by which environmental vertical wind shear can constrain a TC's intensity. An idealized ...

Tang, Brian Hong-An

2010-01-01

461

Tropical Hardwood Tree Improvement & Regeneration Center  

E-print Network

knowledge and developing strategies for conservation, restoration, utilization and marketing of tropical, through its affiliation with HTIRC based at Purdue University, it is a member in the National Science

462

NON-ARCHIMEDEAN AMOEBAS AND TROPICAL VARIETIES  

E-print Network

NON-ARCHIMEDEAN AMOEBAS AND TROPICAL VARIETIES MANFRED to the complex amoeba of an algebraic variety, and show that it coincides with a polyhe- dral set we prove that the amoeba of an irreducible variety is connected. We introduce

Lind, Douglas A.

463

Survey for hantaviruses, tick-borne encephalitis virus, and Rickettsia spp. in small rodents in Croatia.  

PubMed

In Croatia, several rodent- and vector-borne agents are endemic and of medical importance. In this study, we investigated hantaviruses and, for the first time, tick-borne encephalitis virus (TBEV) and Rickettsia spp. in small wild rodents from two different sites (mountainous and lowland region) in Croatia. In total, 194 transudate and tissue samples from 170 rodents (A. flavicollis, n=115; A. agrarius, n=2; Myodes glareolus, n=53) were tested for antibodies by indirect immunofluorescence assays (IIFT) and for nucleic acids by conventional (hantaviruses) and real-time RT-/PCRs (TBEV and Rickettsia spp.). A total of 25.5% (24/94) of the rodents from the mountainous area revealed specific antibodies against hantaviruses. In all, 21.3% (20/94) of the samples from the mountainous area and 29.0% (9/31) from the lowland area yielded positive results for either Puumala virus (PUUV) or Dobrava-Belgrade virus (DOBV) using a conventional RT-PCR. All processed samples (n=194) were negative for TBEV by IIFT or real-time RT-PCR. Serological evidence of rickettsial infection was detected in 4.3% (4/94) rodents from the mountainous region. Another 3.2% (3/94) rodents were positive for Rickettsia spp. by real-time PCR. None of the rodents (n=76) from the lowland area were positive for Rickettsia spp. by real-time PCR. Dual infection of PUUV and Rickettsia spp. was found in one M. glareolus from the mountainous area by RT-PCR and real-time PCR, respectively. To our knowledge, this is the first detection of Rickettsia spp. in small rodents from Croatia. Phylogenetic analyses of S- and M-segment sequences obtained from the two study sites revealed well-supported subgroups in Croatian PUUV and DOBV. Although somewhat limited, our data showed occurrence and prevalence of PUUV, DOBV, and rickettsiae in Croatia. Further studies are warranted to confirm these data and to determine the Rickettsia species present in rodents in these areas. PMID:24866325

Svoboda, Petra; Dobler, Gerhard; Markoti?, Alemka; Kurolt, Ivan-Christian; Speck, Stephanie; Habuš, Josipa; Vucelja, Marko; Krajinovi?, Lidija Cvetko; Tadin, Ante; Margaleti?, Josip; Essbauer, Sandra

2014-07-01

464

Dendroecology in the tropics: a review  

Microsoft Academic Search

Over the last decade the field of tropical dendroecology has developed rapidly and major achievements have been made. We reviewed\\u000a the advances in three main themes within the field. First, long chronologies for tropical tree species were constructed which\\u000a allowed climate reconstructions, revealed sources of climatic variation and clarified climate–growth relations. Other studies\\u000a combined tree-ring data and stable isotope (13C

Danaë M. A. Rozendaal; Pieter A. Zuidema

2011-01-01

465

Tropical environmental dynamics: A modeling perspective  

Microsoft Academic Search

\\u000a The impact of climatic change on tropical vegetation is of global and regional concern because of the high biodiversity and\\u000a the feedbacks to the carbon, water, and nutrient cycles. Tropical ecosystem functioning is governed by complex systems, that,\\u000a in spite of their diversities, share in common structures and characteristic states which can be modeled (Aassine and Jay,\\u000a 2002). Records of

R. Marchant; J. C. Lovett

466

Objective classification of historical tropical cyclone intensity  

NASA Astrophysics Data System (ADS)

Preinstrumental records of historical tropical cyclone activity require objective methods for accurately categorizing tropical cyclone intensity. Here wind force terms and damage reports from newspaper accounts in the Lesser Antilles and Jamaica for the period 1795-1879 are compared with wind speed estimates calculated from barometric pressure data. A total of 95 separate barometric pressure readings and colocated simultaneous wind force descriptors and wind-induced damage reports are compared. The wind speed estimates from barometric pressure data are taken as the most reliable and serve as a standard to compare against other data. Wind-induced damage reports are used to produce an estimated wind speed range using a modified Fujita scale. Wind force terms are compared with the barometric pressure data to determine if a gale, as used in the contemporary newspapers, is consistent with the modern definition of a gale. Results indicate that the modern definition of a gale (the threshold point separating the classification of a tropical depression from a tropical storm) is equivalent to that in contemporary newspaper accounts. Barometric pressure values are consistent with both reported wind force terms and wind damage on land when the location, speed and direction of movement of the tropical cyclone are determined. Damage reports and derived wind force estimates are consistent with other published results. Biases in ships' logbooks are confirmed and wind force terms of gale strength or greater are identified. These results offer a bridge between the earlier noninstrumental records of tropical cyclones and modern records thereby offering a method of consistently classifying storms in the Caribbean region into tropical depressions, tropical storms, nonmajor and major hurricanes.

Chenoweth, Michael

2007-03-01

467

Migration and Species Diversity in the Tropics  

PubMed Central

If the young of a dominant species are subjected to disproportionately heavy predation, this, together with a limitation on food, can promote a high species diversity. This is seen among tropical birds, which are simultaneously exposed to both conditions to a far greater degree than are Temperate Zone species. Migration to the Temperate Zones during the spring provides a release from these restraints, while also precluding breeding in the Tropics. PMID:16592138

Klopfer, P. H.; Rubenstein, D. I.; Ridgely, R. S.; Barnett, R. J.

1974-01-01

468

Osteomyelitis in tropical pyomyositis: a case report.  

PubMed

We report a case of acute tropical pyomyositis in a German girl living in Tanzania. The course of the disease was complicated by osteomyelitis affecting the humerus, which is unusual in tropical pyomyositis. Diagnosis of the osteomyelitis was difficult because a scintigram showed depressed bone activity during the isotope influx and bloodpool phase. The bone phase was abnormal with irregular hypo- and hyperfixation of tracer. PMID:2606125

Fusch, C; Huenges, R; Müller-Schauenburg, W

1989-10-01

469

Algebraic properties of generic tropical varieties  

Microsoft Academic Search

We show that the algebraic invariants multiplicity and depth of a graded\\u000aideal in the polynomial ring are closely connected to the fan structure of its\\u000ageneric tropical variety in the constant coefficient case. Generically the\\u000amultiplicity of the ideal is shown to correspond directly to a natural\\u000adefinition of multiplicity of cones of tropical varieties. Moreover, we can\\u000arecover

Tim Römer; Kirsten Schmitz

2010-01-01

470

Landscape rehabilitation of degraded tropical forest ecosystems  

Microsoft Academic Search

Tropical forest area is disappearing at the rate of 13.5millionha each year, due mainly to clearing for agriculture and shifting cultivation. Timber harvesting results in more than 5millionha of tropical forest annually being transformed into degraded, poorly managed, logged-over forests. The reduction and degradation caused by anthropological activities affect not only the sustainable production of timber but also the global

Shigeo Kobayashi

2004-01-01

471

Elements of tropical Pacific decadal variability  

E-print Network

and content by: njamin S. Giese (C Chair of Committee) ~ ~(V Gerald R. North (Member) Wilford D. Gardner (Head of Department) ing Chang Co-Chair of Committee) May 2003 Major Subject Oceanography ABSTRACT Elements of Tropical Pacific Decadal.... Tropical Pacific Decadal Variability and the 1976-77 Climate Shift B. Elements of Spiciness Decadal Variability. . . . . . . . C. Elements of Isopycnal Depth Decadal Variability. . . . IV CONCLUSIONS . A. Summary B. Discussion . . C. Future...

Fuckar, Neven-Stjepan

2003-01-01

472

Brain development in rodents and humans: Identifying benchmarks of maturation and vulnerability to injury across species  

PubMed Central

Hypoxic-ischemic and traumatic brain injuries are leading causes of long-term mortality and disability in infants and children. Although several preclinical models using rodents of different ages have been developed, species differences in the timing of key brain maturation events can render comparisons of vulnerability and regenerative capacities difficult to interpret. Traditional models of developmental brain injury have utilized rodents at postnatal day 7–10 as being roughly equivalent to a term human infant, based historically on the measurement of post-mortem brain weights during the 1970s. Here we will examine fundamental brain development processes that occur in both rodents and humans, to delineate a comparable time course of postnatal brain development across species. We consider the timing of neurogenesis, synaptogenesis, gliogenesis, oligodendrocyte maturation and age-dependent behaviors that coincide with developmentally regulated molecular and biochemical changes. In general, while the time scale is considerably different, the sequence of key events in brain maturation is largely consistent between humans and rodents. Further, there are distinct parallels in regional vulnerability as well as functional consequences in response to brain injuries. With a focus on developmental hypoxicischemic encephalopathy and traumatic brain injury, this review offers guidelines for researchers when considering the most appropriate rodent age for the developmental stage or process of interest to approximate human brain development. PMID:23583307

Semple, Bridgette D.; Blomgren, Klas; Gimlin, Kayleen; Ferriero, Donna M.; Noble-Haeusslein, Linda J.

2013-01-01

473

Investigating Neural Correlates of Behavior in Freely Behaving Rodents Using Inertial Sensors  

PubMed Central

Simultaneous behavior and multielectrode neural recordings in freely behaving rodents holds great promise to study the neural bases of behavior and disease models in combination with genetic manipulations. Here, we introduce the use of three-axis accelerometers to characterize the behavior of rats and mice during chronic neural recordings. These sensors were small and light enough to be worn by rodents and were used to record three-axis acceleration during freely moving behavior. A two-layer neural network-based pattern recognition algorithm was developed to extract the natural behavior of mice from the acceleration data. Successful recognition of resting, eating, grooming, and rearing are shown using this approach. The inertial sensors were combined with continuous 24-h recordings of neural data from the striatum of mice to characterize variations in neural activity with circadian cycles and to study the neural correlates of spontaneous action initiation. Finally, accelerometers were used to study the performance of rodents in traditional operant conditioning, where they were used to extract the reaction time of rodents. Thus the addition of accelerometer recordings of rodents to chronic multielectrode neural recordings provides great value for a number of neuroscience applications. PMID:20427622

Venkatraman, Subramaniam; Jin, Xin; Costa, Rui M.

2010-01-01

474

Hypothalamic alterations in Huntington's disease patients: comparison with genetic rodent models.  

PubMed

Unintended weight loss, sleep and circadian disturbances and autonomic dysfunction are prevalent features of Huntington's disease (HD), an autosomal dominantly inherited neurodegenerative disorder caused by an expanded CAG repeat sequence in the HTT gene. These features form a substantial contribution to disease burden in HD patients and appear to be accompanied by a number of neuroendocrine and metabolic changes, pointing towards hypothalamic pathology as a likely underlying mechanism. Neuronal inclusion bodies of mutant huntingtin, which are hallmarks of the disease, occur throughout the hypothalamus, and indicate local mutant huntingtin expression that could interfere with hypothalamic neuropeptide production. Also, several genetic rodent models of HD show features that could be related to hypothalamic pathology, such as weight loss and circadian rhythm disturbances. In these rodents, several hypothalamic neuropeptide populations are affected. In the present review, we summarise the changes in genetic rodent mo