9 resultados para Sweat glands
em Brock University, Canada
Resumo:
Sweat bees exhibit a range of social behaviours, from solitary nesting, in which no workers are produced, to strong eusociality, in which workers exhibit a high degree of altruism, behaviour that is measured by the degree of personal reproductive sacrifice. Field studies were carried out for seven weeks during May-June 2000 in southern Greece in order to investigate intraspecific social variation, and test the hypothesis of a north-south cline of decreasing eusociality in the obligately eusocial sweat bee L. (E.) malachurum. A comparative study, using principal components analysis, was performed to determine if patterns of intraspecific social variation in L. malachurum reflect the patterns of social variation within the subgenus, Evylaeus, as a whole. The results of the field study reveal that, in Greece, two worker broods were produced followed by a third brood consisting of gynes, males and some workers, indicating that there was an overlap in worker and gyne production. There was strong caste distinction between queens and workers. Workers actively foraged and participated in nest construction as most workers (58%, n=303) had a high degree of mandibular wear. Workers did not participate in the oviposition of Brood 3 gynes since only 0.7% (n=278) of workers were mated. Furthermore, queen survival until the end of Brood 3 and a substantial size differential of 10.6% between queens and workers suggested that queen domination over worker behaviour during the early to mid-part of the colony cycle was plausible. Male production in Brood 3 by some workers was likely, since the timing of worker ovarian development corresponded with the timing of male production. These findings suggest that workers of the first two broods were primarily altruistic, but some (28%) Brood 1 (9%) and Brood 2 (19%) workers produced males, indicating that the degree of altruistic behaviour declined during the lifetime of the colony. In comparison with other L. malachurum populations in Europe, the Greek population of L. malachurum had a weaker social level as a result of the higher proportion of workers potentially involved in male production, thus 3 supporting the hypothesis of a southerly cline of decreasing eusociality. Furthermore, intraspecific variation in social level across Europe appears to be due to longer breeding seasons in more southerly locations that would promote the production of larger colonies and provide opportunities for workers to evade queen control. The comparative study using principal components analysis on 20 solitary (of the subgenera Evylaeus and Lasioglossum), eusocial and socially polymorphic Evylaeus species and populations reveals that six traits are closely associated with stronger eusociality in Evylaeus. These traits are: (1) a reduction in the proportion of males in the early brood(s); (2) a reduction in the proportion of females that mate; (3) an increase in the mean number of first brood workers; (4) a reduction in the proportion of females with developed ovaries; (5) an increase in size dimorphism between castes, and (6) nest guarding. These are traits that most significantly define principal component one and therefore distinguish social type as indicated by a clear separation of the eusocial and the solitary populations, with a socially polymorphic species falling in between. Furthermore, most of these traits are under foundress control and may suggest that the evolutionary loss or gain of eusociality is based on selection pressures on a founding female. Colony size and female ovarian development are common factors distinguishing social variation in L. malachurum and within the subgenus as a whole. The principal components analysis excluding the solitary species and the socially aberrant L. marginatum populations show the L. malachurum populations separated based on an increasing proportion of workers with developed ovaries as populations are found more south, lending further support to the hypothesis of a north-south cline of decreasing eusociality.
Resumo:
Within the crime film tradition there is a plethora of sub-genres all of which relate to crime and its consequences. However, directors Joel and Ethan Coen, Quentin Tarantino and David Lynch, all of whom create plots around crime and criminality, have been difficult to pin down and attribute to any given sub-genre. This thesis demonstrates that an absurdist philosophy can be used to effectively examine the content of the previously mentioned filmmakers. Through an analysis of these filmmakers and their better known works compelling evidence is revealed suggesting that these filmmakers may all belong to the emerging crime film sub-genre known as absurdist crime films.
Resumo:
Teach, Lean Develop: Sweat, Breathe, Yoga is a Handbook for the Educator intended to be a practical took for educators to integrate yoga into their classrooms and for the betterment of students. The handbook offers teachers several activities and ideas to get them started using yoga in the classroom-these activities can be modified to suit different ages, abilities, and classroom levels. The project includes a look at the literature alongside my opinions and experience from what I have experiences while teaching yoga in the classroom. The handbook itself is intended to assist experiences and inexperienced educators by offering some ideas and activities that will encourage educators to explore using yoga in the classroom. After the completion of the handbook 2 educators reviewed it, and information was collected with regards to how they saw it fitting into their classrooms and the curriculum in general. They provided critiques, constructive feedback, and further recommendations for the handbook.
Resumo:
This study examined relationships among physical activity, body fat and salivary immonoglobulin A (sIgA) levels in adolescent children of Southern Ontario. Gender differences on these factors were also assessed. Sixty-one grade-five students (10-1 lyrs), males (n=29) and females (n=31), who had not received a flu vaccination in the past 12 months, participated in the study. They were assessed for: aerobic power (20-m shuttle run), relative body fat (bioelectrical impedance analysis), sIgA, sIgA/albumin ratio, and salivary Cortisol. Each subject completed the Habitual Activity Estimation Scale and the Participation Questioimaire. Students wore a pedometer for 48h to estimate their average total distance traveled per day. The results show 40% of the children were over 25% body fat and 50% of them spend less than five hours per day in any physical activities. Salivary IgA was not related to salivary Cortisol, physical activity, fitness level or body fat in this age group. There were no gender differences in sIgA and Cortisol levels. Boys had a significantly higher aerobic power and daily distance traveled, but reported similar organized and fi-ee time activity participation levels as the girls. The test-retest reproducibility for salivary Cortisol was 0.663 (p<0.01), while long term sIgA and sIgA/albumin ratio reproducibility was non-significant for repeated measurements taken after six weeks. It was found that salivary IgA has not been shovm to be a stable measure in children, in contrast to the results found in the literatiu-e that tested adults and the relationship with physical activity, fitness level and body fat.
Resumo:
Many studies investigating the relationship between hormones and competition have focused on athletic competition. The athletic setting enables r researchers to investigate the hormone-behaviour relationship in a relatively controlled environment. However, research to date has been based on observations made from single status contests and/or weekend tournaments and as such, does not provide a clear picture of an individual's average hormonal responses to both victory and defeat. In appreciation of this limitation, the current study tracked elite hockey players throughout a hockey season, measuring pre- and post-game salivary testosterone and Cortisol as well as psychological measures. I was interested in determining whether status outcome (win vs. loss) would influence an individual's testosterone and Cortisol responses to competition. Furthermore, I was also interested in assessing whether testosterone and Cortisol responses were specific to the competitive environment or whether similar hormonal responses would occur during non-competitive practice sessions. Last, I was interested in whether there were any differences in pre-game hormonal and psychological states depending on where the status contest was held: home versus away. The results indicated that game outcome moderated the testosterone responses to competition. That is, testosterone increased significantly more after a victory compared to a defeat. Furthermore, a loss of status produced significantly hreports, the players did not show an anticipatory rise in either Cortisol or testosterone prior to competition. In addition to the effects of status outcome on hormonal levels, it was also found that these hormonal responses were specific to competition. The athletes in the current study did not demonstrate any hormonal responses to the practice sessions. Last, there were significant differences in pre-game testosterone as well as in selfconfidence, cognitive, and somatic anxiety levels depending on the location at which the status contest took place. Pre-game testosterone and self-confidence levels were significantly higher prior to games played in the home venue. In contrast, pre-game somatic and cognitive anxiety levels were significantly higher prior to games played in the away venue. The current findings add to the developing literature on the relationship between hormones and competition. This was the first study to detect a moderating effect of status outcome on testosterone responses in a team sport. Furthermore, this was also the first study in humans to demonstrate that post-contest Cortisol levels were significantly higher after a loss of status. Last, the current study also adds to the sport psychology literature by demonstrating that pre-game psychological variables differ depending on where the status contest is being held: higher self-confidence at home and higher somatic and cognitive anxiety away. Taken together, the results from the current thesis may have important practical relevance to coaches, trainers and sport psychologists who are always trying to find ways to maximize performance. post-game Cortisol levels than did an increase in status. In contrast to previous
Resumo:
The relationship between photoperiod, plasma concentration of ionic calcium and the histology of the prolactin-secreting cells of the rostral pars distalis of the pituitary gland, the Corpuscles of Stannius and the Ultimobranchial gland were investigated. Neither the plasma concentration of ionic calcium nor histologically apparent prolactin cell activity could be correlated with photoperiod. Some evidence of a photoperiodic effect on both the Corpuscles of Stannius and the Ultimobranchial gland was obtained. The expected reciprocal relationship between the activity of these glands was not obvious at the histological level . Quantitative and qualitative analysis at the light microscope level revealed, however, that the hormone prolactin-secreting eta cells of the rostral pars distalis and the hypocalcin-secreting cells of the Corpuscles of Stannius may be arranged in a lamellar pattern comprized of synchronous bands of cells in like-phase of a secretory cycle consisting of four stages - synthesis, storage, release and reorganization. Such synchronized cell cycles in these glands have not heretofore been described in literature. It is suggested that the maintenance of at least 255? of the cells in any one phase of the cycle ensures a supply of the required hormone at all times.
Resumo:
Basal body temperature (BBT) and thermoeffector thresholds increase following ovulation in
many women. This study investigated if solely central thermoregulatory alterations are responsible.
Seven females in a non-contraceptive group (NCG) were compared with 5 monophasic contraceptive
users (HCG) on separate accounts: pre-ovulation (Trial I; d 2-5) and post-ovulation (Trial 2; 4-8 d
post-positive ovulation) for NCG, and active phase for HCG (d 2-5, d 18-21). During immersion in
28°C water to the axilla, participants exercised for 20-30 min on an underwater ergometer. After
steadily sweating, immersion continued until metabolism increased two-fold due to shivering. Rectal
(Tre) BBT was not different between trials for neither NCG (1: 37.34±0.16°C; 2: 37.35±0.27°C) nor
HCG. At exercise termination, Tre forehead sweating cessation increased (P<0.05) in trial 2
irrespective of group (1: 37.55±0.39°C; 2: 37.90±0,46°C). Tre shivering onset did not increase
(P>0.05) in trial 2 (1: 36.91±0.50°C; 2: 37.07±0,45°C). The widths of the interthreshold zone
increased (P<0.05) in trial 2 (1: 0.64±0.22°C; 2: 0.82±0.37°C) due to the increased sweating threshold
only. HCG cooled quicker (1: -l.15±0,43°C; 2: -1.00±0.50°C) than NCG participants (1: -
0.58±0.22°C; 2: -0.52±O.29°C), and tympanic (Tty) sweat thresholds were significantly (P<0.05)
decreased (1: 34.76±0.54°C; 2: 35.39±0.61°C) versus NCG (l: 35.57±0.77°C; 2: 35.89±1.04°C).
Lastly, Tre and Tty thresholds were significantly different (P
Resumo:
Type 1 Diabetes Mellitus (T1DM) is an autoimmune disease that destroys pancreatic beta cells, affecting glucose homeostasis. In T1DM, glucoregulation and carbohydrate oxidation may be altered in different ambient temperatures; however, current literature has yet to explore these mechanisms. This study examines the effects of 30 minutes of exercise at 65% VO2max in 5ºC, 20ºC and 35ºC in individuals with T1DM. No significant differences were observed for blood glucose across the 3 conditions (p = 0.442), but significance was found for core temperature, heat storage, and sweat rate (p < 0.01). Blood glucose was also shown to vary greatly between individuals among conditions. The mechanisms behind the differences in blood glucose may be due to the lack of significant glucagon production among conditions. These findings suggest that T1DM individuals may exercise submaximally for 30 minutes in different ambient temperatures without significant differences in glucoregulation.
Resumo:
Black fly (Simuliidae) silk is produced by the larvae and pharate pupae and is used for anchorage and cocoon production. There exists limited information on simuliid silks, including protein composition and genetic sequences encoding such proteins. The present study aimed to expand what is known about simuliid silks by examining the silks of several simuliid species and by making comparisons to the silk of non-biting midges (Chironomidae). Silk glands were dissected out of larval and pupal simuliids, and protein contents were separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and visualized with silver stain. Protein contents were compared by mass in kilodaltons (kDa) between life stages and among species. Polymerase chain reaction (PCR) was used to expand upon known gene sequence information, and to determine the presence of genes homologous to chironomid silk. SDS-PAGE of cocoons revealed the presence of a 56 kDa and a 67 kDa protein. Silk gland contained as many as 28 different proteins ranging from 319 kDa to 8 kDa. Protein profiles vary among species, and group into large (>200), intermediate(>100), and small (<100) protein classes as is found in chironomids. It is likely that silk evolved in a common ancestor of simuliids and chironomids