Les altérations du cycle veille/sommeil sont fréquentes dans le milieu militaire. Elles induisent une dégradation des performances, et peuvent potentiellement causer des conséquences sur l’état de santé à long terme des personnels. Ce travail de thèse a pour objectif d’évaluer deux contre-mesures, l’effet de 6 nuits d’extension de sommeil d’une part et les effets de 8 semaines d’entrainement physique d’autre part sur la performance cognitive (attention soutenue, inhibition, mémoire de travail), la pression de sommeil, les réponses endocriniennes et inflammatoires, et la fonction neuromusculaire au cours d’une privation totale de sommeil et de la récupération subséquente. Les résultats principaux mettent en évidence que six nuits d’extension de sommeil ont pour effet de limiter (i) la dégradation de la performance cognitive (attention soutenue et mémoire de travail) et physique, (ii) l’apparition de micro-sommeils observées au cours d’une période de privation totale de sommeil. L’extension de sommeil a également induit une diminution des concentrations circulantes de prolactine et une augmentation des concentrations circulantes d’IGF-1. Les résultats ont également montré que 8 semaines d’entrainement physique permettent de limiter la dégradation de la performance psychomotrice (i.e. conduite simulée) induite par la privation totale de sommeil sans modifications significatives des réponses endocriniennes. Ainsi, ces types de stratégies préventives permettraient de limiter les dégradations de la performance et pourraient être combinées à des contre-mesures nutritionnelles et/ou pharmacologiques / The alterations of sleep/wake cycle are frequent in military area. They induce performance degradation and can potentially induced some consequences on health status in the long-term among military personnel. The aim of this thesis work is to assess two countermeasures, the effects of six nights of sleep extension and the effects of 8 weeks of physical training on cognitive performance (sustained attention, inhibition, working memory), sleep pressure, hormonal and inflammatory responses and neuromuscular function during total sleep deprivation and the subsequent period. The main results are that 6 nights of sleep extension limit (i) degradation of cognitive performance (sustained attention and working memory) and physical performance, (ii) involuntary micro-sleeps during total sleep deprivation period. Likewise, the sleep extension induces a decrease of circulating prolactin concentration and an increase of circulating IGF-1 concentration. Results have shown that 8 weeks of physical training limit the degradation of psychomotor performance (i.e. simulated driving) induced by total sleep deprivation without changes in hormonal responses. Thus these kinds of preventives strategies would limit the performance degradation and could be combined with nutritional and/or pharmacological countermeasures

Please read the abstract in the section 00front of this document / Dissertation (MSc (Agric))--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted

Sexually-selected communication signals can be used by competing males to settle contests without incurring the costs of fighting. The ability to dynamically regulate the signal in a context-dependent manner can further minimize the costs of male aggressive interactions. Such is the case in the gymnotiform fish Brachyhypopomus gauderio, which, by coupling its electric organ discharge (EOD) waveform to endocrine systems with circadian, seasonal, and behavioral drivers, can regulate its signal to derive the greatest reproductive benefit. My dissertation research examined the functional role of the EOD plasticity observed in male B. gauderio and the physiological mechanisms that regulate the enhanced male EOD. To evaluate whether social competition drives the EOD changes observed during male-male interactions, I manipulated the number of males in breeding groups to create conditions that exemplified low and high competition and measured their EOD and steroid hormone levels. My results showed that social competition drives the enhancement of the EOD amplitude of male B. gauderio. In addition, changes in the EOD of males due to changes in their social environment were paralleled by changes in the levels of androgens and cortisol. I also examined the relationship between body size asymmetry, EOD waveform parameters, and aggressive physical behaviors during male-male interactions in B. gauderio, in order to understand more fully the role of EOD waveforms as reliable signals. While body size was the best determinant of dominance in male B. gauderio, EOD amplitude reliably predicted body condition, a composite of length and weight, for fish in good body condition. To further characterize the mechanisms underlying the relationship between male-male interactions and EOD plasticity, I identified the expression of the serotonin receptor 1A, a key player in the regulation of aggressive behavior, in the brains of B. gauderio. I also identified putative regulatory regions in this receptor in B. gauderio and other teleost fish, highlighting the presence of additional plasticity. In conclusion, male-male competition seems to be a strong selective driver in the evolution of the male EOD plasticity in B. gauderio via the regulatory control of steroid hormones and the serotonergic system.

Migration timing is a conserved life-history trait. To address the hypothesis that reproductive hormones are principal determinants of migration timing, I physiologically biopsied over 1000 sockeye salmon and monitored their subsequent behaviour with acoustic and radio telemetry as they migrated from the Pacific Ocean toward and into the Fraser River, and then onward to distant spawning areas. Links between physiology, behaviour, and survival were examined. Circulating testosterone was found to be positively correlated with the rates of river entry in Late-run females but not in males, despite having concentrations that were equal if not higher than those of females. The notion of protandrous migration, in which males synchronize their activities to the reproductive and migratory schedules of females, was postulated as the basis for this difference. Once in river however, successful males and females were those that (1) took longest to enter the river, and (2) had high somatic energy, low testosterone, and low gill Na+,K+-ATPase activities. An experimental test of the effect of reproductive hormones on the regulation of migration timing proved inconclusive. Relative to controls, GnRH and (or) testosterone treatment did not influence rates of ocean travel by males. Unfortunately, no females were examined. Nevertheless, significant, positive correlations between initial testosterone and travel times were found irrespective of hormonal treatment, which was unexpected but consistent with the previous studies. In an experimental simulation of an ‘early’ migration, normally timed Late-run sockeye exposed to typical 10 ºC river temperatures and then released to complete migration were 68% successful. In contrast, salmon held at 18 °C and released were half as successful. The expression of a kidney parasite was near maximal in the 18 °C fish and undetectable in the 10 °C fish. Only gill Na+,K+-ATPase activity differed between groups, with a drop in the 18 °C fish. Though no clear stress, reproductive, or energetic differences were observed between groups, the ultimate effect of high temperature treatment was high disease expression, slowed migration speeds, and high migration mortality. Changes in reproductive schedules, due to changes in latitudinal ocean distributions, are discussed as potential causes of early migration by Late-run sockeye. / Forestry, Faculty of / Graduate

Fluid secretion by insect Malpighian tubules is controlled by haemolymph-bome factors. Two corticotropin-releasing-factor (CRF)-related diuretic peptides, Tenmo¬DH37 and Tenmo-DH47. previously isolated from Tenebrio molitor, were found to stimulate in vitro tubule preparations of Tenebrio molitor via the second messenger cyclic AMP. The stimulatory effect of Tenmo-DH37 was reversed on addition of endogenous antidiuretic peptides (Tenmo-ADFa and ADFb) and exogenous cardioacceleratory peptide 2b (CAP2b), both acting via the second messenger cyclic GMP. The immunocytochemical localization of Tenmo-DH37 and the second antidiuretic peptide isolated from Tenebrio molitor, Tenmo-ADFb, was investigated using antisera raised against these hormones. Neurosecretory cells immunoreactive to Tenmo-DH37 were found in the brain and abdominal ganglia with immunoreactive processes projecting to the peripheral nervous system. Intense staining of the neurohaemal release site, the corpora cardiaca, was observed. In addition, neurosecretory cells immunoreactive to Tenmo-DH37 were found in the posterior midgut and a network of immunoreactive nerve processes extended over the surface of the midgut. Tenmo-ADFb immunoreactivity was localized in the brain, in two pairs of bilaterally symmetrical cells in the protocerebrum. Tenebrio tubule secretion appears entirely dependent on the surrounding K+ concentration and intracellular measurements of the basolateral (Vbl) and indirectly apical membrane potentials (Vap) indicate an appreciable sensitivity of both membranes to the bath K+ concentration, but not to Na+. Secretion assay and electrophysiological results indicate that K+ uptake across the basolateral membrane is primarily through barium-sensitive K+ channels, but also implicate a bumetanide-sensitive Na+/K+/2CI cotransporter, an ouabain-sensitive Na+/KV+-ATPase and glibenclamide-sensitive KATP channels. Furthermore, electrophysiological evidence suggests that fluid secretion/inhibition by endogenous factors is achieved by influencing at least three parameters simultaneously: the rate of H+ extrusion by the V-ATPase, basolateral K+ conductance, and possibly CI- conductance. The effect of amiloride on fluid secretion and pH indicates the presence of a cationic H+ exchanger in Malpighian tubules of Tenebrio. To our knowledge the mealworm Tenebrio molitor provides the first known example of antagonistic interactions between endogenous neuropeptides acting on Malpighian tubules and this study is the first to demonstrate the presence of KATP channels in an insect epithelium. / Thesis (DPhil (Zoology))--University of Pretoria, 2006. / Zoology and Entomology / unrestricted

Bakgrund: Diabetes är en folksjukdom som drabbar allt fler i världen.Från år 1980 har antalet personer med diabetes ökat från ca 108 miljoner till 422miljoner år 2014. Diabetes typ 1 och diabetes typ 2 är de vanligast förekommandetyperna av diabetes. Diabetes typ 2 är i hög grad ärftlig men det finns fleralivsstilsförändringar människan kan göra för att förebygga eller minska risken förkomplikationer, bland annat ökad fysisk aktivitet. Vid diabetes typ 2rekommenderar Socialstyrelsen 30 minuter medelintensiv fysisk aktivitet per dageller 150 minuter medelintensiv fysisk aktivitet per vecka.Syfte: Syftet med litteraturstudien var att undersöka det vetenskapliga stödet förolika egenvårdsinsatser som sjuksköterskan kan rekommendera för att öka fysiskaktivitet hos patienter med diabetes typ 2.Metod: En litteraturstudie baserad på studier med kvantitativ ansats hargenomförts. Deltagarna i studierna var vuxna patienter med diabetes typ 2.Interventionernas syfte var att öka den fysiska aktiviteten hos deltagarna.Resultatet i litteraturstudien bygger på data från tio olika vetenskapliga artiklarfrån databaserna Cinahl och PubMed.Resultat: Olika former av insatser från sjuksköterskan exempelvis rådgivande,individuell- eller grupputbildning samt med hjälp av olika tekniska hjälpmedelsom komplement visade resultat i form av ökad fysisk aktivitet hos deltagarna.Konklusion: Det finns ett flertal insatser som kan hjälpa patienter med diabetestyp 2 att öka sin fysiska aktivitet och minska risken för diabetesrelateradekomplikationer. I genomförandet av dessa insatser har sjuksköterskan en viktigpedagogisk, motiverande och stödjande roll gentemot patienterna.

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Background: Diabetes is the seventh leading cause of death in the United States. More and more people have suffered from diabetes and its serious complications including heart disease, blindness, etc. The U.S. Department of Veterans Affairs (VA) reported that nearly 25% of veterans, enrolled in the Veterans Health Administration (VHA),have diabetes, which is much higher than the general population. Objective: This study aimed to estimate the prevalence of diabetes in the U.S. veterans using the up-to-date National Health and Nutrition Examination Survey (NHANES) data since VHA has a relatively low coverage (less than 30% of veterans each year were enrolled). Methods: Five biennial cross sectional surveys (NHANES) from 2005-2014 were used in this study. Total 2,940 veterans were included to estimate the prevalence of diabetes. Total diabetes was defined as any participant who had at least one of four conditions: (1) a hemoglobin A1c at least 6.5%, (2) fasting plasma glucose (FPG) at least 126mg/dL, (3)a 2-hour plasma glucose (PG) at least 200mg/dL, (4) diagnosed with diabetes by a doctor or other health professional. Results: The overall prevalence of total diabetes(including diagnosed and undiagnosed diabetes), undiagnosed diabetes and obesity were 20.54%, 3.37% and 40.68%, respectively. The family poverty level and education were significantly associated with the presence of diabetes with p=0.005 and 0.03,respectively. Highest prevalence diabetes and obesity existed in veterans aged 65yrs and over and 45-64yrs, respectively. The overall prevalence trend of diabetes significantly increased from 15.52% (95%CI: 12.36-18.68%) in 2005-2006 to 20.54% (95%CI:15.92-25.17%) (p=0.04 for trend test) and prevalence significantly increased in male veterans (p=0.04) and those who did not finish high school education (p=0.04) and who had college education (p=0.03). Conclusion: In 2013-2014, the estimated prevalence of diabetes was 20.54% among U.S. veterans, with higher prevalence among participants who were 65 years old or older, and had low socioeconomic status (including less education and poverty status).

Understanding how African elephants (Loxodonta africana) respond to human interactions in ecotourism operations is critical to safeguarding animal and human welfare and sustaining wildlife ecotourism activities. We investigated the stress response of elephants to a variety of tourist activities over a 15-month period at Abu Camp in northern Botswana. We compared fecal glucocorticoid metabolite (FGM) concentrations across three elephant groups, including: eight elephants in an elephant-tourism operation (Abu herd), three elephants previously reintroduced back into the wild from the Abu herd, and wild elephants. There were no differences in FGM concentrations between the three groups of elephants. The highest observed FGM concentrations were associated with episodic events (e.g. intraherd conflict, loud noise, physical injury) unrelated to tourist activities. FGM concentrations differed between the elephant-tourist activities with ride only and mixed ride/walk activities eliciting higher FGM concentrations compared to days when there were no elephant-tourist interactions. The elephant experience tourism industry faces challenges in managing elephants who’s aggressive or unpredictable behavior makes them ill-suited to captivity, training, and interaction with handlers and tourists. Reintroduction of these elephants back into the wild may be a favorable solution if the welfare of released individuals, recipient wild animal populations, and human populations can be ensured. We describe the post-release movements of two African elephants, one female and one bull, from an elephant-back-safari enterprise in the Okavango Delta, Botswana. We compared the movements of the female with that of two wild females collared in the same wildlife management concession. We assess their home range size, proximity to human dwellings, and fidelity to their former home range as former members of their semi-captive, working herd from which they were released. We found significant differences between the home range size of our released elephant and that of the two wild elephants. Additionally, the released female and released bull occurred more frequently in close proximity (within 250 m) to tourist lodges throughout the Delta. The released elephants also frequented sites used by the working Abu herd with greater frequency than the wild elephants, and this visitation rate did not significantly decline during respective four- and two-year post-release monitoring periods, despite the positive growth in home range size.