Search results for "Reproduction"
showing 10 items of 752 documents
Interactions of the hormones leptin, ghrelin, adiponectin, resistin, and PYY3-36 with the reproductive system.
2006
Objective To summarize the effects of novel hormones (leptin, ghrelin, adiponectin, resistin, and PYY3-36) secreted from adipose tissue and the gastrointestinal tract that have been discovered to exert different effects on several reproductive functions, such as the hypothalamic–pituitary–gonadal axis, embryo development, implantation physiology, and clinically relevant conditions. Design A MEDLINE computer search was performed to identify relevant articles. Result(s) Leptin and ghrelin exert important roles on body weight regulation, eating behavior, and reproduction, acting on the central nervous system and target reproductive organs. As a marker of adequate nutritional stores, these horm…
The role of the leptin in reproduction.
2006
Since its discovery in 1994, leptin has appeared to be a pleiotrophic hormone, governing energy homeostasis and affecting many tissues in the body. Numerous pieces of evidence have accumulated showing that leptin potentially plays an important role in the control of the reproductive function.This review presents the major concepts for the role of leptin in the modulation of reproductive function. As a marker of the nutritional status, leptin affects the hypothalamo-pituitary-gonadal axis, regulating gonadotrophin-releasing hormone and luteinising hormone secretion, and appears to be a permissive factor in the onset of the puberty. This protein and its receptor have been found in the reprodu…
Asexual multiplication of larval parasitic worms: a predictor of adult life-history traits in Taeniidae?
2001
The hypothesis that asexual multiplication inside the intermediate host and adult life-history traits within the final host are independent is tested among Cestoda. Using phylogenetic relationships among the Cestoda species, we can show that asexual multiplication appears to have been lost and recovered several times throughout Taeniidae evolution; this allows a comparison of the adult life-history traits of species with and without asexual multiplication at the larval stage. The adult trait considered is the size of the parasite, since numerous life-history traits, such as fecundity and longevity, are correlated with size. If adult traits are independent of whether the larval stage reprodu…
Classification of Spanish Mosquitoes in Functional Groups
2011
Abstract We present a classification of Spanish mosquitoes according to their different life cycles. The bio-ecological parameters analyzed in our study were oviposition sites, overwintering stages, preferred hosts, and number of generations per year for each species. The results revealed 13 different functional groups. To assess the validity and robustness of the classification system, we analyzed the data from an intensive sampling carried out over a period of 4 years (2005–08) in eastern Spain. In this area, 9 of the 13 functional groups were found. The Jaccard cluster and the principal components analysis (between-group analysis method) revealed 3 different mosquito groups: the tree hol…
Absence of Sex Differential Plasticity to Light Availability during Seed Maturation in Geranium sylvaticum
2015
Sex-differential plasticity (SDP) hypothesis suggests that since hermaphrodites gain fitness through both pollen and seed production they may have evolved a higher degree of plasticity in their reproductive strategy compared to females which achieve fitness only through seed production. SDP may explain the difference in seed production observed between sexes in gynodioecious species in response to resource (nutrients or water) availability. In harsh environments, hermaphrodites decrease seed production whereas females keep it relatively similar regardless of the environmental conditions. Light availability can be also a limiting resource and thus could theoretically affect differently femal…
The problem of spatial homogeneity in an LCoS projector
2019
Abstract Video projectors allow interesting applications in vision sciences since they provide a large projection area. We have colorimetrically characterized a LCoS projector using a mathematical model requiring additivity and constancy of the primaries -a sigmoid function in our case. Significant differences in chromaticity in the CIELAB space, but not in lightness, were found between the center and the corners of the screen. The lack of spatial homogeneity led us to estimate the parameters of the model as a function of spatial position, using different strategies. The best result was obtained by interpolating the values of the parameters of the model determined from experimental measurem…
Taxonomic complexity in the halophyte Limonium vulgare and related taxa (Plumbaginaceae): insights from analysis of morphological, reproductive and k…
2014
Part of a special issue on halophytes and saline adaptations Background and Aims Limonium is awell-known example of a group of plants that is taxonomically complex due to certain biological characteristics that hamper species’ delineation. The closely related polyploid species Limonium vulgare Mill., L. humile Mill. and L. narbonense Mill. are defined species and can be used for studying patterns of morphological and reproductive variation. The first two taxa are usually found in Atlantic Europe and the third in the Mediterranean region, but a numberof intermediate morphological formsmay be present alongside typical examples of these species. This study attempts to elucidate morphological, …
Invited to labour or participate : intra- and inter-generational distinctions and the role of capital in children’s invited participation
2016
This paper applies aspects of Bourdieu’s conceptual toolkit related to capital, and analyses inter- and intra-generational relations of influence. Applying Bourdieu’s concepts to examples of case studies from a children’s parliament in Finland, and with reference to an adult resident forum, moments of continuity and disruption in the relatively stable patterns of distinction between children and adults emerge. Children in school councils (at times) are labourers for agendas set by teachers, but the children at the top of the structure’s hierarchy can benefit from cultural capital and a functional capital that enables them to set agendas and direct the work of others. The political capital o…
Assessing the Cost of Mounting an Immune Response
2003
International audience; The evolution of parasite resistance has often been assumed to be governed by antagonistic selection pressures. Defense against pathogens, by mounting an immune response, confers evident benefits but may also incur costs, so that the optimal level of defense is expected to depend on the balance between benefits and costs. Although the benefits of immune surveillance are well known, estimates of costs are still equivocal. Here we studied the behavioral and physiological modifications associated with exposure to a onreplicating antigen (lipopolysaccharide [LPS] of Escherichia coli) in a passerine species, the house sparrow (Passer domesticus).We further investigated wh…
EFFECT OF A 48H DELAYED INSEMINATION WITH OR WITHOUT A 48H DOE-LITTER SEPARATION ON PERFORMANCE OF NON-RECEPTIVE RABBIT DOES
2010
[EN] The effectiveness of delayed artificial insemination (DAI) of non-receptive (R-) does, with or without oestrus synchronisation by doe-litter separation (MLS), was studied and compared with receptive (R+) does. During 10 months, 105 NZW does, in three homogeneous groups (A, B, C), were artificially inseminated (Al) according to a 42-day reproduction rhythm in two batches. Every 21 days, two Al were effected, the second 48 hours alter the first. The R+ does of ali groups were inseminated al the first Al, while the R- does were treated, in relation to theirgroup, as follows: inseminated at the first Al (A); 48-hour DAI (B); 48-hour MLS by closing the nestbox before Al, when lactating, and…