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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
341

Proposta de metodologia de predição de sensação térmica dos usuários em ambientes internos / A methodological proposal of predicted mean vote for people in closed environments

Broday, Evandro Eduardo 01 October 2015 (has links)
CNPq / O PMV (Voto Médio Estimado) é um índice que pretende prever a sensação térmica das pessoas expostas a um mesmo ambiente. Entretanto, existem discrepâncias entre o modelo do PMV e as respostas de sensação térmica obtidas em estudos de campo efetuados para algumas populações. Um dos componentes para o cálculo do PMV é o isolamento térmico das vestimentas (Icl), que se utiliza da temperatura de superfície da vestimenta (tcl), que pode ser um fator que contribui para estas discrepâncias. Assim, esta pesquisa teve como objetivo apresentar um novo modelo de predição térmica minimizando as imprecisões das trocas térmicas pela correta determinação do tcl, utilizando-se do método de Newton. A coleta de dados contou com um grupo de soldadores, um grupo de trabalhadores de escritório desempenhando atividades sedentárias e um grupo de militares do exército português. Com a coleta de variáveis ambientais e pessoais no Brasil e em Portugal, esta pesquisa desenvolveu o Snovo1, por meio de um valor de tcl sem resíduos gerado pelo método de Newton e substituído nas parcelas de convecção e radiação de perda de calor e o Snovo2, mediante regressão múltipla entre os votos de sensação térmica coletados em estudo de campo, a taxa metabólica e os mecanismos de troca de calor. Depois do confronto entre a sensação térmica real e os valores de PMV calculados, para todos os grupos, os resultados encontrados com o Snovo1 e Snovo2 sempre foram melhores que os resultados encontrados com o PMV original de Fanger. O melhor resultado obtido nesta pesquisa foi com o grupo de militares, onde o Snovo2 apresentou uma melhoria de aproximadamente 46% em relação ao PMV original. Esta pesquisa comprovou que a temperatura superficial da vestimenta é uma variável de influência no modelo do PMV e minimizar imprecisões em sua obtenção diminui as discrepâncias entre os votos de sensação térmica e o PMV. / The PMV (Predicted Mean Vote) is an index which aims to predict the thermal sensation of people exposed to the same environment. However, there are discrepancies between the PMV model and thermal sensation responses obtained in field studies for some populations. One of the components for the calculation of PMV is the clothing insulation (Icl), which uses the clothing surface temperature (tcl), which can be a factor which contributes towards these discrepancies. Therefore, the aim of this research was to show the tcl influence on the PMV index. Thus, this research aimed to present a new thermal prediction model minimizing inaccuracies of thermal exchanges through the correct determination of tcl, by using Newton's method. Data collection featured a group of welders, a group of office workers performing sedentary activities and a group of Portuguese Army Military. Having collected environmental and personal variables in Brazil and Portugal, this research developed the Snew1, through a value of tcl without residues generated by Newton’s Method and replaced in convection and radiation heat loss equations and Snew2, through multiple regression between thermal sensation votes collected in field study, the metabolic rate and the mechanisms of heat exchange. After confrontation between the real thermal sensation and the calculated PMV values, for all groups, the results found with the Snew1 and Snew2 were always better than the results found with the Fanger’s Original PMV. The best result obtained in this research was with the military group, where the Snew2 presented an improvement about 46% over the original PMV. This search proved that the clothing surface temperature is a variable that influences the PMV model and minimizing inaccuracies in its obtaining decreases discrepancies between thermal sensation votes and PMV.
342

Proposta de metodologia de predição de sensação térmica dos usuários em ambientes internos / A methodological proposal of predicted mean vote for people in closed environments

Broday, Evandro Eduardo 01 October 2015 (has links)
CNPq / O PMV (Voto Médio Estimado) é um índice que pretende prever a sensação térmica das pessoas expostas a um mesmo ambiente. Entretanto, existem discrepâncias entre o modelo do PMV e as respostas de sensação térmica obtidas em estudos de campo efetuados para algumas populações. Um dos componentes para o cálculo do PMV é o isolamento térmico das vestimentas (Icl), que se utiliza da temperatura de superfície da vestimenta (tcl), que pode ser um fator que contribui para estas discrepâncias. Assim, esta pesquisa teve como objetivo apresentar um novo modelo de predição térmica minimizando as imprecisões das trocas térmicas pela correta determinação do tcl, utilizando-se do método de Newton. A coleta de dados contou com um grupo de soldadores, um grupo de trabalhadores de escritório desempenhando atividades sedentárias e um grupo de militares do exército português. Com a coleta de variáveis ambientais e pessoais no Brasil e em Portugal, esta pesquisa desenvolveu o Snovo1, por meio de um valor de tcl sem resíduos gerado pelo método de Newton e substituído nas parcelas de convecção e radiação de perda de calor e o Snovo2, mediante regressão múltipla entre os votos de sensação térmica coletados em estudo de campo, a taxa metabólica e os mecanismos de troca de calor. Depois do confronto entre a sensação térmica real e os valores de PMV calculados, para todos os grupos, os resultados encontrados com o Snovo1 e Snovo2 sempre foram melhores que os resultados encontrados com o PMV original de Fanger. O melhor resultado obtido nesta pesquisa foi com o grupo de militares, onde o Snovo2 apresentou uma melhoria de aproximadamente 46% em relação ao PMV original. Esta pesquisa comprovou que a temperatura superficial da vestimenta é uma variável de influência no modelo do PMV e minimizar imprecisões em sua obtenção diminui as discrepâncias entre os votos de sensação térmica e o PMV. / The PMV (Predicted Mean Vote) is an index which aims to predict the thermal sensation of people exposed to the same environment. However, there are discrepancies between the PMV model and thermal sensation responses obtained in field studies for some populations. One of the components for the calculation of PMV is the clothing insulation (Icl), which uses the clothing surface temperature (tcl), which can be a factor which contributes towards these discrepancies. Therefore, the aim of this research was to show the tcl influence on the PMV index. Thus, this research aimed to present a new thermal prediction model minimizing inaccuracies of thermal exchanges through the correct determination of tcl, by using Newton's method. Data collection featured a group of welders, a group of office workers performing sedentary activities and a group of Portuguese Army Military. Having collected environmental and personal variables in Brazil and Portugal, this research developed the Snew1, through a value of tcl without residues generated by Newton’s Method and replaced in convection and radiation heat loss equations and Snew2, through multiple regression between thermal sensation votes collected in field study, the metabolic rate and the mechanisms of heat exchange. After confrontation between the real thermal sensation and the calculated PMV values, for all groups, the results found with the Snew1 and Snew2 were always better than the results found with the Fanger’s Original PMV. The best result obtained in this research was with the military group, where the Snew2 presented an improvement about 46% over the original PMV. This search proved that the clothing surface temperature is a variable that influences the PMV model and minimizing inaccuracies in its obtaining decreases discrepancies between thermal sensation votes and PMV.
343

O efeito da dessincroniza??o circadiana sobre o metabolismo / The effect of circadian desynchronization about metabolism

Fortes, Fabiano Santos 24 August 2011 (has links)
Made available in DSpace on 2014-12-17T15:37:00Z (GMT). No. of bitstreams: 1 FabianoSF_DISSERT_01_62.pdf: 3851800 bytes, checksum: b73c04797e225854ba518eea0fe07fb3 (MD5) Previous issue date: 2011-08-24 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The lost of phase relationship between rhythms and behaviour can, and often do, undesirable consequences. The purpose os study was to ascertain the effect of circadian desynchronization in T22 about metabolism of wistar rats. The subjects consisted of 24 animals separated in two groups: control (n=12) T24 with 8 weeks of aged and experimental group (n=12) T22, also with 8 weeks of aged. Both the groups were subject to register of locomotor actitivity, body temperature, body weight and food intake in all the experiment. And more, both the groups were subject to food deprivation, running in treadmill and forced swimming. The results show rhythm of locomotor activity and body temperature desynchronized. Dont exist diference in body weight between both the groups (T24 = 386,75?40,78g e T22 380,83?44,28g) . However, the food intake was different between the phases, light and dark, in intergroup and intragroup. The body temperature was not different in food deprivation. The same ocurred for running in treadmill and forced swimming. Since similar alterations occur in shift workers, it is proposed that the experimental paradigm presented in this manuscript is a useful model of shift work. That is, alterations in activity/rest cycles and consummatory behavior can affect the health of organism / A perda da rela??o de fase entre os ritmos biol?gicos e o comportamento pode gerar consequ?ncias indesej?veis a um organismo. Diante disso, o objetivo do trabalho foi verificar o papel da dessincroniza??o for?ada em ciclo claro-escuro sim?trico de 22h (T22) sobre o metabolismo de ratos wistar. Participaram do estudo 24 animais divididos em dois grupos: grupo controle (n=12) T24 - com dois meses de idade e grupo experimental (n=12) T22, tamb?m com dois meses de idade. Ambos os grupos tiveram o registro da atividade locomotora, temperatura corporal, peso corporal e consumo alimentar durante os 110 dias de experimento. Al?m disso, ambos os grupos foram submetidos a priva??o e restri??o de alimento, corrida em esteira e nado for?ado para verificar a resposta termog?nica as situa??es. Os resultados apontaram que houve dessincroniza??o do ritmo de atividade locomotora assim como da temperatura corporal. N?o houve diferen?a entre a m?dia do peso corporal ao longo de todo experimento (T24 = 386,75?40,78g e T22 380,83?44,28g). Entretanto, o consumo alimentar foi diferente entre as fases, clara e escura, no mesmo grupo e entre os dois grupos. J?, a temperatura corporal durante a priva??o e restri??o de alimento n?o diferiu entre os grupos. O mesmo aconteceu para a atividade f?sica for?ada (corrida em esteira e nata??o for?ada). A mudan?a do padr?o de atividade locomotora juntamente com a mudan?a no consumo alimentar indicam que o protocolo adotado pode ser eficiente para produzir o que acontece durante o trabalho em turnos. Ou seja, uma dessincroniza??o interna. Com isso, a atividade locomotora e o consumo alimentar ficam alocados mais constantemente na fase de inatividade do animal o que pode geral malef?cios a sa?de de um organismo
344

Využitelnost měření teploty povrchu těla zvířat / Usability of measurement of animal surface temper

SOBÍŠKOVÁ, Kateřina January 2018 (has links)
The aim of the dissertation was to present technical possibilities of scanning and measuring the body temperature and provide a method for a non-contact measurement of body surface temperatureof animals including data transfer to higher-level software. Partial results can be part of an automated herd management system to ensure better animal welfare monitoring. One method of contactless measuring the surface temperature was taking the surface temperature by using an infrared camera. This tool was used to scan surface temperatures in the area of the body core, the udder region and the eye area. Thermograms, sometimes referred to as thermal imaging, were obtained from the individual regions. In total, there were 34 measurements in 2013 and 17 measurements in 2014.Cows from Petrovice centre were included in the experiment. Three different groups of dairy cows were evaluated in two different stables. In the first group there were cows which gave birth 2 days to 2 months before. The second group consisted of dairy cows which calved 4 to 5 months before. The third group included dairy cows which gave birth 7 to 8 months before. Based on the results of measurements of selected surface temperatures, it was found that the surface core temperature and the udder surface temperature correlated most. However, when measuring surface temperatures, the degree of pollution, coating, and oscillation of the animal play an important role. Moreover, technological parameters of the device are also important, specially its setting and the emissivity of the surface. This experiment ran from August to September 2016 in a purpose-built schoolhouse facility in an experimental stable accredited for experimental purposes. The experiment included two clinically healthy cows of the Holstein breed, which had been implanted with the identification chip and tested for its functionality. This chip was implanted to both animals in the tail root region and was fitted with a biological function sensor that followed the body temperature of the animal. The device was adapted to send animal identification information and animal body temperature information by means of a wireless connection to the chip reader. Based on the findings, one or more systems, preferably non-contact body temperature scanning, could be designed and tested. Regarding the use of other surface temperature scanning possibilities, this is still in the process of development and implementation. The disadvantage of the above described device is that it fails to recognize the cause of the elevated temperature and requires intervention by the attendant without the intervention being necessary. The attending keeper may not recognize acute cases and may cause permanent damage to the health or even death of the animal. The task of the device is to find a method of unattended animal temperature measurement connected with its electronic identification that would recognize sick or infected animals from overheated ones. This device would categorize the animals and take precautions to preserve their health. The invention should be applicable to a wide variety of animals.
345

Termoregulační schopnosti rypoše \kur{Fukomys darlingi} a jejich vývoj u mláďat / The Thermoregulatory Abilities in a Mole-rat \kur{Fukomys darlingi} and its Development in Pups

ZEMANOVÁ, Milada January 2010 (has links)
The oxygen consumption and body temperature were measured in adults and pups of a social Mashona mole-rat(Fukomys darlingi)to test poikilothermic traits in this species and effect of presence of adults on pup´s thermoregulation abilities. The adult´s resting metabolic rate was 0.76 {$\pm$} 0.20 mlO2g-1hod-1 in the thermoneutral zone 27-34°C. We did not confirm poikilotermic traits in this species, because body temperature was stable (33.0 {$\pm$} 0.5°C) at low ambient temperatures. The pups started to thermoregulate in age of one month and they are able to maintain stable body temperature very late in age of three months. My results indicate that presence of adults is necessary for thermoregulation of pups.
346

Termoregulační schopnosti rypoše \kur{Fukomys darlingi} a jejich vývoj u mláďat / The Thermoregulatory Abilities in a Mole-rat \kur{Fukomys darlingi} and its Development in Pups

ZEMANOVÁ, Milada January 2010 (has links)
The oxygen consumption and body temperature were measured in adults and pups of a social Mashona mole-rat(Fukomys darlingi)to test poikilothermic traits in this species and effect of presence of adults on pup´s thermoregulation abilities. The adult´s resting metabolic rate was 0.76 {$\pm$} 0.20 mlO2g-1hod-1 in the thermoneutral zone 27-34°C. We did not confirm poikilotermic traits in this species, because body temperature was stable (33.0 {$\pm$} 0.5°C) at low ambient temperatures. The pups started to thermoregulate in age of one month and they are able to maintain stable body temperature very late in age of three months. My results indicate that presence of adults is necessary for thermoregulation of pups.
347

Avaliação clínica de enfermagem na termoregulação do recém-nascido pré-termo: do desenvolvimento ao uso de tecnologia educacional digital / Nursing clinical assessment of thermoregulation of preterm neonates: from development to use of digital educational technology

Marisa Rufino Ferreira Luizari 09 February 2017 (has links)
As tecnologias, fortemente representadas pelos serious games na atualidade, têm ressignificado o processo de ensino-aprendizagem em saúde e enfermagem, contribuindo para o ensino participativo e mediando a aprendizagem não só de estudantes, mas também de profissionais e pacientes. Este estudo consistiu em pesquisa metodológica quanto ao desenvolvimento, baseado na técnica do design participativo, de um jogo educativo denominado e-Baby: avaliação clínica da termorregulação no recém-nascido pré-termo, bem como em um quase-experimento do tipo pré e pós-teste, ao avaliar o nível de aprendizado obtido pelos participantes antes e após uma intervenção, a qual consistiu em um curso semipresencial de 30 horas abordando o tema \'termorregulação do recém-nascido prematuro\' em associação com o jogo desenvolvido, que foi disponibilizado online durante todo o decorrer da atividade de educação permanente. Ao se compararem as médias do pós-teste e as do pré-teste (teste não paramétrico de Wilcoxon), verificou-se aprendizagem significativa pelos participantes (p = 0,0001). O jogo e-Baby voltado à avaliação clínica da termorregulação do recém-nascido pré-termo mostrou-se eficaz como instrumento de intervenção no processo de ensino-aprendizagem, despertando interesse e motivação em seus usuários / Information technology, today remarkably exemplified in serious games, has transformed the teaching-learning process in health and nursing, helping promote participative education and mediating the learning of students, professionals and patients. This study comprised a methodological investigation on the development, based on participative design, of the serious game e-Baby: Clinical Evaluation of Thermoregulation in the Preterm Neonate. A quasi-experimental pre- and post-test study assessed the level of learning available before and achieved after an intervention consisting of a combined on-site/on-line 30-hour refresher course on the topic of thermoregulation in preterm neonates, during which the game was made available online. Comparison between mean scores of post- and pre-assessments (Wilcoxon\'s non-parametric test) revealed significant learning gains (p = 0.0001). The e-Baby serious game for clinically assessing thermoregulation of preterm neonates proved effective as an intervention instrument in the teaching-learning process, sparking the interest and motivation of its users
348

Maturação sexual, ciclos reprodutivos e da temperatura no roedor rabo-de-facho (trinomys yonenagae, echimyidae) / Sexual maturity, reproductive cycles and the temperature in the torch-tail rodent (Trinomys yonenagae, Echimyidae)

Lilian Cristina Luchesi 25 June 2010 (has links)
Os ratos-de-espinho são abundantes nas florestas úmidas Neotropicais. Trinomys yonenagae (ROCHA, 1995) constitui uma exceção entre as espécies do gênero por habitar o campo de dunas fixas da Caatinga, ser colonial e fossorial. Tanto o ambiente seco, como a socialidade e o hábito fossorial podem alterar o padrão reprodutivo das espécies. Diante do fato desses roedores serem coloniais, por exemplo, espera-se a influência de co-específicos (fêmeas ou machos) no ciclo estral. Estudos-piloto na natureza e em cativeiro mostraram que a fase de diestro pode ocorrer com a vagina aberta, um fato que merece ser mais investigado, já que se considera que a abertura vaginal ocorra somente durante a transição da fase proestro-estro. O objetivo deste trabalho é, portanto, o de estudar aspectos dos ritmos reprodutivos infradianos (ciclo estral e gestação) e circadiano (temperatura corporal) em rabos-de-facho, mantidos em cativeiro, alojados individualmente, e pareados com fêmeas e com machos. Nesses grupos são caracterizados os esfregaços e o estado de abertura da vagina, buscando conhecer aspectos da fisiologia reprodutiva, tais como, a idade de maturidade sexual (cap. 1), a relação entre a fase do ciclo estral e o estado vaginal (cap. 2), e as características da citologia esfoliativa durante a gravidez (cap. 3). Os dados da citologia são correlacionados com o padrão comportamental durante o acasalamento, caracterizando a existência de estro pós-parto (cap. 3). Analisa-se ainda a distribuição de todos os nascimentos ocorridos ao longo de dez anos. O ritmo de temperatura corporal das fêmeas é aferido a partir de acompanhamento da temperatura retal com uso de termômetro digital durante 72h (cap. 4). Embora de maneira geral Trinomys yonenagae siga os padrões reprodutivos de outros membros da família Echimyidae, tais como, gestação longa (90d), ninhadas pequenas (média de 2 filhotes) e maturidade sexual tardia (ao redor dos 90d) é possível identificar a influência de co-específicos (dominância entre fêmeas) no ciclo estral. Este ciclo parece ser espontâneo, do tipo poliéstrico, com fases muito curtas de proestro e estro (< 24h). A condição vaginal não é um bom indicativo de atividade reprodutiva (ocorre abertura no diestro e na gravidez); a presença do macho não garante fecundação; também se confirma a ocorrência de estro pós-parto, igualmente breve. O comportamento de acasalamento é elaborado, o que é esperado de espécies com estro curto ou de vida social e subterrânea. A distribuição dos nascimentos não é sazonal, confirmando dados de campo. Quanto ao ritmo de temperatura corporal, ele é circadiano com picos noturnos e com relação positiva de fase com o ritmo de atividade/repouso, o que segue o padrão geral de roedores / Spiny rats are among the most numerous group of mammals in Neotropical rainforests. Trinomys yonenagae (ROCHA, 1995) is an exception because it is colonial, fossorial and inhabits the semiarid Caatinga. The dry environment and the underground and colonial life styles are known to affect reproductive patterns. So it is expected, for example, that social life may influence the estrous cycle especially through the presence of conspecific (females and males). It is considered that vaginal opening occurs only during the estrus. Previous field studies or in captivity have shown the unexpected occurrence of vaginal opening and diestrus, a fact that deserves further investigation. The aim of this work is verify the reproductive infradian rhythms (estrous cycle and pregnancy) and the circadian body temperature rhythm, in T. yonenagae kept individually or in pairs (male-female and female-female) in captivity. In these groups vaginal smears and the presence of the vaginal membrane is studied aiming to characterize aspects of its reproductive life, such as, the age of sexual maturity (chapter 1), the relationship between the vaginal opening and the phase of the estrous cycle (chapter 2), and the smear cytology during pregnancy (chapter 3). The cytological data are correlated with the mating behavioral, characterizing the post-partum estrus (chapter 3). All birth that occurrence during 10 years are analyzed. The body temperature rhythm is measured during 72h by rectal temperature with a digital thermometer (chapter 4). Although Trinomys yonenagae follows the reproductive patterns of other members of Echimyidae, such as prolonged gestation( 90d), small sized litter (mean of 2) and delayed sexual maturity (around 90d), it is possible to identify the influence of conspecifics (female dominance) upon the estrous cycle. This cycle seems to be spontaneous, poliestric, having very short proestrus and estrus phases (< 24h). The vaginal condition is not a good indicative of the reproductive status (vaginal opening may occur during the diestrus phase and the pregnancy); the presence of males does not guarantee pregnancy. We also confirm the occurrence of post-partum estrus, which is also short-lived. The mating behavior is complex, which is expected in species were the duration of estrus is short, or in species of social and subterranean life. The birth distribution is non seasonal, which is in agreement with field data. The body temperature rhythmicity is circadian with peaks at night; and shows a positive phase relationship with the rest/activity rhythm, both cycles follow the pattern known for other nocturnal rodents
349

Influência da temperatura na ecologia e no comportamento de Callicebus nigrifrons (Primates: Pithecilidae) / Temperature influence on ecology and behavior of Callicebus nigrifrons (Primates: Pithecilidae)

Gestich, Carla Cristina, 1986- 20 August 2018 (has links)
Orientadora: Eleonore Zulnara Freire Setz / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T18:03:19Z (GMT). No. of bitstreams: 1 Gestich_CarlaCristina_M.pdf: 2412818 bytes, checksum: 3850c0adff0e3465f46c136d4a4903b3 (MD5) Previous issue date: 2012 / Resumo: A alteração das necessidades energéticas dos endotérmicos pela variação da temperatura ambiental devido aos custos da termorregulação pode influenciar seu comportamento. O objetivo desse estudo foi investigar a influência da temperatura nos comportamentos de sauás (Callicebus nigrifrons) na Serra do Japi, região com marcada sazonalidade e temperatura reduzida pela altitude. Para isso, relacionamos com a temperatura: o padrão de atividade, os itens alimentares e os comportamentos termorregulatórios durante o descanso (seleção de micro-hábitat, contato entre os indivíduos e postura corporal). Quanto menores as temperaturas mínimas noturnas, o que pode representar estresse térmico, os sauás iniciaram suas atividades mais tardiamente, no momento em que a temperatura ambiental já estava elevada. A distância percorrida diariamente não variou com a temperatura, mas os sauás locomoveram mais no início do dia, horário mais frio, coincidindo com o início das atividades. Entre os meses, a locomoção foi menor nos mais frios, possivelmente resultando em economia de energia. Não houve seleção por itens alimentares mais calóricos em temperaturas baixas. Entretanto, houve aumento no forrageio nos meses mais frios (não relacionado com a disponibilidade de frutos), compatível com a ideia de que os custos da termorregulação podem influenciar a ingestão de alimentos. A seleção de locais ao sol foi maior em temperaturas baixas, e tal comportamento pode estar reduzindo os custos da termorregulação com o aumento da absorção de calor da radiação solar. O contato entre os indivíduos ao longo do dia não teve relação com a temperatura e pode ter sido influenciado somente pelas interações sociais. A postura não variou em função da temperatura e aquelas que resultavam em menor perda de calor para o meio foram predominantemente adotadas. Isso, provavelmente, devido ao porte pequeno da espécie (elevada razão superfície/volume) que contribui para maior perda de calor nas baixas temperaturas registradas. Conclui-se que os sauás apresentam variação comportamental em função da temperatura ambiental quanto à escolha de micro-hábitats e padrão de locomoção e forrageio / Abstract: Variations in ambient temperature can change the energy requirements of endothermics due to costs of thermoregulation. So, ambient temperature can influence animal's behavior. The aim of this work was to investigate ambient temperature influence on wild black-fronted titi monkeys (Callicebus nigrifrons) behavior. We conducted this study in Serra do Japi, region with marked seasonality and temperature reduced due to high altitude. We analyzed the relation between temperature and the following variables: activity pattern, types of food consumed and thermoregulatory behaviors observed during resting (microhabitat selection, contact between individuals and body posture). In lower night minimum temperatures, which may represent thermal stress to titi monkey, they started their activities later in the day, after ambient temperature increase. There was no correlation between path length and ambient temperature, but titis moved more at beginning of the day (at the coldest hours), when they were starting these activities. During the coldest months, titis moved less, which could be a strategy to save energy. During this period, they did not select higher-calorie food items, but there was an increase in foraging behavior (not related to fruit availability), which is consistent with the idea that the energy costs of thermoregulation can influence food intake. The sunny resting places were selected at low temperatures. This behavior could be used to reduce thermoregulation costs, allowing the increase of heat absorption from solar radiation. The contact between individuals throughout the day was not related to the temperature and may be influenced only by social interactions. Body postures were not influenced by ambient temperature and postures that avoid heat loss were predominantly adopted. This is probably due to the small size of the species (considering the high surface/volume ratio) which contributes to greater heat loss at low temperatures. We concluded that titi monkey's behaviors vary in function of ambient temperature, such as microhabitat choice and pattern of moving and foraging / Mestrado / Ecologia / Mestre em Ecologia
350

Thermal, hormonal and cardiovascular responses to single and repeated nonhypothermic cold exposures in man

Korhonen, I. (Ilkka) 18 November 2008 (has links)
Abstract The purpose of this study was to find out and compare the physiological effects of different types of non-hypothermic cold exposure tests in man. In whole-body cold exposures lightly clothed subjects were exposed to 10°C for 2 hours (single exposure), as well as repeatidly for 2 h and 1 h on ten successive days in separate studies. For local cold exposures, cold pressor tests (immersion into ice-cold water) of both hands and both feet were used. In whole-body cold exposures, several hormonal and metabolic parameters as well as cold sensations were measured. In local cold exposures the measured parameters were blood pressure, heart rate and skin temperatures. The single 2-h whole-body cold air exposure decreased rectal and skin temperatures and body heat content, but increased the metabolic rate. At the same time the serum noradrenaline concentration increased indicating a general activation of the sympathetic nervous system. Serum free fatty acid concentration increased whereas cortisol, GH and prolactin concentrations fell. No significant changes were found in serum concentrations of adrenalin, TSH, T3, T4, testosterone or LH. Serum total proteins were enhanced apparently due to cold-induced hemoconcentration. After repeating the 2-h whole-body cold exposure for five days the increase in serum noradrenaline level was markedly lower in the cold. At the same time hemoconcentration, judged from serum protein concentrations, was attenuated and the subjects became habituated to the cold sensations. However, the results showed that the repeated 1-h cold exposure in 10°C was not sufficiently intensive to reduce the noradrenaline response. Comparison of the hand and foot cold pressor tests to whole-body cold exposure tests showed that all tests caused significant increases in systolic and diastolic blood pressures, but that heart rate increased significantly only in the cold pressor test of feet. During the 2-h cold air exposure the heart rate fell. This caused a reduction in rate pressure product (RPP, the product of heart rate and systolic blood pressure). In both cold pressor tests the rate pressure product increased, indicating the enhancement of the O2-need in the heart muscle. The results showed no significant correlation in systolic or diastolic blood pressures between whole-body and local cooling of hands or feet. The lack of the association between local and whole-body cold exposure tests may be due to differences in severity and site of the tests: whole-body cold exposure tests cause general cold discomfort while cold pressor tests cause local cold pain. / Tiivistelmä Tämän tutkimuksen tarkoituksena oli selvittää ja verrata eri tyyppisten lievien kylmäaltistustestien fysiologisia vaikutuksia ihmiseen. Yksittäisessä koko kehon kylmäaltistuksessa koehenkilöt olivat kevyesti vaatetettuina kahden tunnin ajan 10°C:n lämpötilassa. Toistetussa koko kehon kylmäaltistuksessa koehenkilöt oleskelivat myös 10°C:n lämpötilassa kahden tai yhden tunnin ajan kymmenenä perättäisenä päivänä. Paikallisessa kylmäaltistuksessa käytettiin kylmävesitestiä (ns. cold pressor koe). Testi tehtiin sekä käsille että jaloille. Koko kehon kylmäaltistuksessa mitattiin useita hormonaalisia, aineenvaihdunnan ja lämpötasapainon vasteita, sekä verenpainetta ja sydämen syketiheyttä. Paikallisissa kylmäaltistuksissa mitattiin verenpainetta, sydämen syketiheyttä ja iholämpötiloja. Yksittäinen koko kehon kahden tunnin kylmäaltistus laski syvälämpötilaa, iholämpötiloja ja kehon lämpösisältöä. Samanaikaisesti kehon lämmöntuotanto kasvoi. Seerumin noradrenaliinipitoisuus lisääntyi ilmentäen sympaattisen hermoston tehostunutta aktivoitumista. Seerumin vapaiden rasvahappojen pitoisuus kasvoi, samoin kokonaisproteiinipitoisuus, mutta kasvuhormonin, kortisolin ja prolaktiinin osalta todettiin pitoisuuksien vähenemistä. Merkitseviä muutoksia ei tapahtunut seerumin adrenaliinissa, TSH:ssa, T3:ssa, T4:ssä, testosteronissa tai LH:ssa. Toistetussa kahden tunnin pituisessa kylmäaltistuksessa seerumin noradrenaliinipitoisuudessa tapahtunut kasvu oli merkitsevästi vähäisempää viiden päivän jälkeen. Samanaikaisesti seerumin proteiinipitoisuus kylmässä väheni ja kylmätuntemukset muuttuivat lievemmiksi. Sen sijaan yhden tunnin toistettu altistus 10°C:ssa ei ollut riittävän voimakas vähentämään kylmän aiheuttamaa veren noradrenaliinipitoisuuden kasvua. Verenpaineen ja sydämen syketiheyden reaktioita verrattiin samoilla koehenkilöillä yksittäisessä kahden tunnin koko kehon kylmäaltistuksessa ja kylmävesitesteissä. Kaikki nämä testit kohottivat merkitsevästi systolista ja diastolista verenpainetta. Sydämen syketiheys laski koko kehon kylmäaltistuksessa. Jalkojen kylmävesitestissä sydämen syketiheys nousi merkitsevästi, mutta käsien testissä tämä nousu ei ollut merkitsevä. Verenpaineen nousu koko kehon kylmäaltistuksessa ei korreloinut merkitsevästi paikallisissa kylmäaltistuksissa mitattuihin verenpaineen nousuihin. Selittävänä tekijänä tähän lienee näiden kylmäaltistusmuotojen erilaisuus. Lievä koko kehon kylmäaltistus aiheuttaa yleistä epämiellyttävyyttä, kun taas äkilliseen, nopean iholämpötilan laskun aiheuttamaan paikalliseen kylmäaltistukseen liittyy usein kiputuntemuksia.

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