899 resultados para Sperm Competition
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Strong consolidation is one of the most evident developments of banking markets around the world in recent decades. This change is raising questions on how and to what an extent competition is affected by the expansion of the largest banks. The aim of the present study is to measure the degree of competition in the Portuguese commercial banking market in the long-run, during the period ranging from1960 to 2013, by using the non-structural model developed by Panzar and Rosse. The main findings are that the Portuguese banking system, despite the legal restrictions in place, operated mostly in a market with some degree of competition and, at some points in time, presented some interesting competitive features. More recently, it has evolved into functioning as a cartel.
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This paper studies the effects of reimbursement for medical tourism within the European Union. We use a spatial competition framework to study the effects on prices, qualities and patient flows between two countries. Patient mobility increases with the implementation of reimbursement mechanisms. The resulting equilibria in prices and qualities depend on the rule of reimbursements and possible differences in country specific parameters. Soft budget constraints that public providers may have, pose a competitive advantage over private providers and divert demand toward the former. Supranational coordination concerning soft budgets constraints is needed to address the potentially detrimental effects on aggregate welfar
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IntroductionRecently, pathogen ecology has been recognized as an important epidemiological determinant of healthcare-associated infections (HAIs). Acinetobacter baumannii is one of the most important agents known to cause HAIs. It is widespread in healthcare settings and exhibits seasonal variations in incidence. Little is known about the impact of competition with other hospital pathogens on the incidence of A. baumannii infection.MethodsWe conducted an ecological study, enrolling patients who presented with healthcare-associated bloodstream infections (HA-BSIs) from 2005 to 2010 at a 450-bed teaching hospital in Brazil. HA-BSIs were said to be present when bacteria or fungi were recovered from blood cultures collected at least three days after admission. Monthly incidence rates were calculated for all HA-BSIs (overall or caused by specific pathogens or groups of pathogens). Multivariate Poisson regression models were used to identify the impacts of the incidence of several pathogens on the incidence of A. baumannii.ResultsThe overall incidence rate of HA-BSI caused by A. baumannii was 2.5 per 10,000 patient-days. In the multivariate analysis, the incidence of HA-BSI caused by A. baumanniiwas negatively associated with the incidence rates of HA-BSI due to Staphylococcus aureus (rate ratio [RR]=0.88; 95% confidence interval [CI]=0.80-0.97), Enterobacter spp. (RR=0.84; 95%CI=0.74-0.94) and a pool of less common gram-negative pathogens.ConclusionsOur results suggest that competition between pathogens influences the etiology of HA-BSIs. It would be beneficial to take these findings into account in infection control policies.
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The existence of competition policy forces companies to adjust their behaviour. This is also costly. Using a database from a company on contracts, I will try to estimate if a specific competition policy disposition, supply contracts cannot be longer than 60 months, has costs for the coffee suppliers operating in the Portuguese “on-trade” coffee market. The estimation method used in this paper will be OLS. The results suggest that limiting the duration of exclusivity contracts to 60 months can be harmful to the coffee suppliers and it can even seriously affect the market functioning. Key
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PURPOSE: The objective was to describe the results of the injection of immotile spermatozoa with flexible tails when only immotile spermatozoa are present in the semen sample. METHODS: A retrospective study was conducted to analyze the procedure results for 10 couples who participated in our intracytoplasmic sperm injection program. The sperm tail was considered flexible when it moved up and down independently of the head movement, and it was considered inflexible when the movement occurred together (tail plus head). The fertilization and pregnancy rate were analyzed. RESULTS: The normal fertilization rate (presence of 2 pronuclei) was 30.3% (40/132), and the abnormal fertilization rate (presence of less than or more than 2 pronuclei) was 6.81% (9/132). A total of 52 embryos were obtained with 9 transfer procedures performed (pregnancy rate: 11.12%). CONCLUSIONS: The sperm tail flexibility test (STFT) is an easy and cost-effective way for selecting viable immotile spermatozoa and can be used as an alternative method for determining the viability of spermatozoa. This test seems to be a simple and risk-free method when compared to the swelling test.
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Dissertação de mestrado em Direito dos Negócios, Europeu e Transnacional
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Research and development around indoor positioning and navigation is capturing the attention of an increasing number of research groups and labs around the world. Among the several techniques being proposed for indoor positioning, solutions based on Wi-Fi fingerprinting are the most popular since they exploit existing WLAN infrastructures to support software-only positioning, tracking and navigation applications. Despite the enormous research efforts in this domain, and despite the existence of some commercial products based on Wi-Fi fingerprinting, it is still difficult to compare the performance, in the real world, of the several existing solutions. The EvAAL competition, hosted by the IPIN 2015 conference, contributed to fill this gap. This paper describes the experience of the RTLS@UM team in participating in track 3 of that competition.
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El objetivo general del proyecto es estudiar el efecto de la progesterona y de algunas proteínas del plasma seminal sobre la actividad del Ca2+ en diferentes procesos fisiológicos que ocurren en el espermatozoide, los cuales están estrechamente relacionados con la capacidad fertilizante de esta célula. La progesterona, principal esteroide secretado por las células del cumulus oophorus, ejerce su efecto a través de un receptor no-genómico provocando aumento en el calcio intracelular de los espermatozoides y, consecuentemente, promoviendo la capacitación, la respuesta quimiotáctica y la exocitosis acrosomal. Pese a estas observaciones, los mecanismos a través de los cuales la progesterona estimula fenómenos tan diversos en el espermatozoide son aún desconocidos. Tampoco se conoce con exactitud el papel funcional y los mecanismos de acción de algunas proteínas del plasma seminal que interaccionan y se unen a los espermatozoides, con alta especificidad, durante la eyaculación. Por lo tanto, resulta altamente interesante profundizar los estudios sobre las propiedades funcionales de las proteínas caltrin (calcium transport inhibitor) y ß-microseminoprotein (MSP) del plasma seminal de mamíferos, las cuales responden a las características mencionadas. Los estudios hasta ahora realizados han dado cuenta de que caltrin inhibe la incorporación de Ca2+ extracelular, previene la exocitosis acrosomal espontánea y promueve la unión espermatozoide-zona pelúcida. También hay datos preliminares que sugieren un efecto inhibitorio sobre la movilidad hiperactivada de los espermatozoides. Respecto a MSP, sólo se sabe que inhibe la exocitosis acrosomal espontánea y que su contenido, en el plasma seminal, guarda una relación inversa con la fertilidad. Por todo lo expuesto, se propone estudiar los mecanismos de acción de la progesterona y las proteínas caltrin y MSP sobre los procesos fisiológicos antes indicados. Para ello, se estudiarán las variaciones de Ca2+ intracelular en espermatozoides individuales sometidos a diferentes tratamientos (gradientes de progesterona, capacitación en presencia y ausencia de caltrin y/o MSP, etc.), usando video microscopía de fluorescencia y análisis computarizado de imágenes. También se examinará la influencia de estas moléculas sobre la interacción de gametas y la fertilización.
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La ingeniería genética y la reprogramación de organismos vivos representan las nuevas fronteras biotecnológicas que permitirán generar animales con modificaciones precisas en sus genomas para un sinnúmero de aplicaciones biomédicas y agropecuarias. Las técnicas para inducir modificaciones génicas intencionales en animales, especialmente en especies mayores de interés agropecuario, se encuentran rezagadas si se compara con los avances significativos que se han producido en el área de la transgénesis de roedores de laboratorio, especialmente el ratón. Es así que, el presente proyecto persigue desarrollar y optimizar protocolos para generar embriones bovinos transgénicos para aplicaciones biotecnológicas. La estrategia propuesta, se basa en conseguir la presencia simultánea en el interior celular de una enzima de restricción (I-SceI) más un transgén (formado por casetes de expresión de una proteína fluorescente -ZsGreen1- y neomicina fosfotransferasa). Específicamente, proyectamos estudiar una vía alternativa para generar embriones bovinos transgénicos mediante la incorporación del transgén (casetes ZsGreen1 y neo) flanqueado por sitios I-SceI más la enzima I-SceI al interior del ovocito junto con el espermatozoide durante la técnica conocida como inyección intracitoplasmática de espermatozoides (ICSI). Los embriones así generados se cultivarán in vitro, inspeccionándolos diariamente para detectar la emisión de fluorescencia, indicativa de la expresión de la proteína ZsGreen1. Los embriones que alcancen el estado de blastocisto y expresen el transgén se transferirán quirúrgicamente al útero de ovejas sincronizadas y se mantendrán durante 7 días. Al cabo de este período, los embriones se recolectarán quirúrgicamente del útero ovino y se transportarán al laboratorio para determinar el número de sitios de integración y número de copias del transgén mediante el análisis de su ADN por Southern blot. Se prevé que los resultados de esta investigación permitirán sentar las bases para el desarrollo de métodos eficientes para obtener modificaciones precisas en el genoma de los animales domésticos para futuras aplicaciones biotecnológicas. Genetic engineering and reprogrammed organisms represent the new biotechnological frontiers which will make possible to generate animals with precise genetic modifications for agricultural and biomedical applications. Current methods used to generate genetically modified large animals, lay behind those used in laboratory animals, specially the mouse. Therefore, we seek to develop and optimize protocols to produce transgenic bovine embryos through the use of a non-viral vector. The strategy involves the simultaneous presence inside the cell of a restriction enzyme (I-SceI) and a transgene (carrying cassettes for a fluorescent protein -ZsGreen1- and neomycin phosphotransferase) flanked by restriction sites for the endonuclease. We plan to develop an alternative approach to generate transgenic bovine embryos by coinjecting the transgene flanked by I-SceI restriction sites plus the enzyme I-SceI along with the spermatozoon during the technique known as intracytoplasmic sperm injection (ICSI). Embryos will be cultured in vitro and inspected daily with a fluorescence microscope to characterize transgene expression. Embryos that reach the blastocyst stage and express the transgene will be surgically transfer to the uterus of a synchronized ewe. After 7 days, the embryos will be flushed out the ovine uterus and transported to the laboratory to determine the number of integration sites and transgene copies by Southern blot. We anticipate that results from this research will set the stage for the development of efficient strategies to achieve precise genetic modifications in large domestic animals for future biotechnological applications.
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This paper deals with problems on population genetics in Hymenoptera and particularly in social Apidae. 1) The studies on populations of Hymenoptera were made according to the two basic types of reproduction: endogamy and panmixia. The populations of social Apinae have a mixed method of reproduction with higher percentage of panmixia and a lower of endogamy. This is shown by the following a) males can enter any hive in swarming time; b) males of Meliponini are expelled from hives which does not need them, and thus, are forced to look for some other place; c) Meliponini males were seen powdering themselves with pollen, thus becoming more acceptable in any other hive. The panmixia is not complete owing to the fact that the density of the breeding population as very low, even in the more frequent species as low as about 2 females and 160 males per reproductive area. We adopted as selection values (or survival indices) the expressions according to Brieger (1948,1950) which may be summarised as follows; a population: p2AA + ²pq Aa + q2aa became after selection: x p2AA + 2pq Aa + z q²aa. For alge-braics facilities Brieger divided the three selective values by y giving thus: x/y p2 AA + y/y 2 pq Aa + z/y q²aa. He called x/y of RA and z/y of Ra, that are survival or selective index, calculated in relation to the heterozygote. In our case all index were calculated in relation to the heterozygote, including the ones for haploid males; thus we have: RA surveval index of genotype AA Ra surveval index of genotype aa R'A surveval index of genotype A R'a surveval index of genotype a 1 surveval index of genotype Aa The index R'A ande R'a were equalized to RA and Ra, respectively, for facilities in the conclusions. 2) Panmitic populations of Hymenoptera, barring mutations, migrations and selection, should follow the Hardy-Weinberg law, thus all gens will be present in the population in the inicial frequency (see Graphifc 1). 3) Heterotic genes: If mutation for heterotic gene ( 1 > RA > Ra) occurs, an equilibrium will be reached in a population when: P = R A + Ra - 2R²a _____________ (9) 2(R A + Ra - R²A - R²a q = R A + Ra - 2R²A _____________ (10) 2(R A + Ra - R²A - R²a A heterotic gene in an hymenopteran population may be maintained without the aid of new mutation only if the survival index of the most viable mutant (RA) does not exced the limiting value given by the formula: R A = 1 + √1+Ra _________ 4 If RA has a value higher thah the one permitted by the formula, then only the more viable gene will remain present in the population (see Graphic 10). The only direct proof for heterotic genes in Hymenoptera was given by Mackensen and Roberts, who obtained offspring from Apis mellefera L. queens fertilized by their own sons. Such inbreeding resulted in a rapid loss of vigor the colony; inbred lines intercrossed gave a high hybrid vigor. Other fats correlated with the "heterosis" problem are; a) In a colony M. quadrifasciata Lep., which suffered severely from heat, the percentage of deths omong males was greater .than among females; b) Casteel and Phillips had shown that in their samples (Apis melifera L). the males had 7 times more abnormalities tian the workers (see Quadros IV to VIII); c) just after emerging the males have great variation, but the older ones show a variation equal to that of workers; d) The tongue lenght of males of Apis mellifera L., of Bombus rubicundus Smith (Quadro X), of Melipona marginata Lep. (Quadro XI), and of Melipona quadrifasciata Lep. Quadro IX, show greater variationthan that of workers of the respective species. If such variation were only caused by subviables genes a rapid increasse of homozigoty for the most viable alleles should be expected; then, these .wild populations, supposed to be in equilibrium, could .not show such variability among males. Thus we conclude that heterotic genes have a grat importance in these cases. 4) By means of mathematical models, we came to the conclusion tht isolating genes (Ra ^ Ra > 1), even in the case of mutations with more adaptability, have only the opor-tunity of survival when the population number is very low (thus the frequency of the gene in the breeding population will be large just after its appearence). A pair of such alleles can only remain present in a population when in border regions of two races or subspecies. For more details see Graphics 5 to 8. 5) Sex-limited genes affecting only females, are of great importance toHymenoptera, being subject to the same limits and formulas as diploid panmitic populations (see formulas 12 and 13). The following examples of these genes were given: a) caste-determining genes in the genus Melipona; b) genes permiting an easy response of females to differences in feeding in almost all social Hymenoptera; c) two genes, found in wild populations, one in Trigona (Plebéia) mosquito F. SMITH (quadro XII) and other in Melipona marginata marginata LEP. (Quadro XIII, colonies 76 and 56) showing sex-limited effects. Sex-limited genes affecting only males do not contribute to the plasticity or genie reserve in hymenopteran populations (see formula 14). 6) The factor time (life span) in Hymenoptera has a particular importance for heterotic genes. Supposing one year to be the time unit and a pair of heterotic genes with respective survival indice equal to RA = 0, 90 and Ra = 0,70 to be present; then if the life time of a population is either one or two years, only the more viable gene will remain present (see formula 11). If the species has a life time of three years, then both alleles will be maintained. Thus we conclude that in specis with long lif-time, the heterotic genes have more importance, and should be found more easily. 7) The colonies of social Hymenoptera behave as units in competition, thus in the studies of populations one must determine the survival index, of these units which may be subdivided in indice for egg-laying, for adaptive value of the queen, for working capacity of workers, etc. 8) A study of endogamic hymenopteran populations, reproduced by sister x brother mating (fig. 2), lead us to the following conclusions: a) without selection, a population, heterozygous for one pair of alleles, will consist after some generations (theoretically after an infinite number of generation) of females AA fecundated with males A and females aa fecundated with males a (see Quadro I). b) Even in endogamic population there is the theoretical possibility of the presence of heterotic genes, at equilibrium without the aid of new mutations (see Graphics 11 and 12), but the following! conditions must be satisfied: I - surveval index of both homozygotes (RA e Ra) should be below 0,75 (see Graphic 13); II - The most viable allele must riot exced the less viable one by more than is permited by the following formula (Pimentel Gomes 1950) (see Gra-fic 14) : 4 R5A + 8 Ra R4A - 4 Ra R³A (Ra - 1) R²A - - R²a (4 R²a + 4 Ra - 1) R A + 2 R³a < o Considering these two conditions, the existance of heterotic genes in endogamic populations of Hymenoptera \>ecames very improbable though not - impossible. 9) Genie mutation offects more hymenopteran than diploid populations. Thus we have for lethal genes in diploid populations: u = q2, and in Hymenoptera: u = s, being u the mutation ratio and s the frequency of the mutant in the male population. 10) Three factors, important to competition among species of Meliponini were analysed: flying capacity of workers, food gathering capacity of workers, egg-laying of the queen. In this connection we refer to the variability of the tongue lenght observed in colonies from several localites, to the method of transporting the pollen in the stomach, from some pots (Melliponi-ni storage alveolus) to others (e. g. in cases of pillage), and to the observation that the species with the most populous hives are almost always the most frequent ones also. 11) Several defensive ways used for Meliponini to avoid predation are cited, but special references are made upon the camouflage of both hive (fig. 5) and hive entrance (fig. 4) and on the mimetism (see list in page ). Also under the same heading we described the method of Lestrimelitta for pillage. 12) As mechanisms important for promoting genetic plasticity of hymenopteran species we cited: a) cytological variations and b) genie reserve. As to the former, duplications and numerical variations of chromosomes were studied. Diprion simile ATC was cited as example for polyploidy. Apis mellife-ra L. (n = 16) also sugests polyploid origen since: a) The genus Melipona, which belongs to a" related tribe, presents in all species so far studied n = 9 chromosomes and b) there occurs formation of dyads in the firt spermatocyte division. It is su-gested that the origin of the sex-chromosome of Apis mellifera It. may be related to the possible origin of diplo-tetraploidy in this species. With regards to the genie reserve, several possible types of mutants were discussed. They were classified according to their survival indices; the heterotic and neutral mutants must be considered as more important for the genie reserve. 13) The mean radius from a mother to a daghter colony was estimated as 100 meters. Since the Meliponini hives swarm only once a year we may take 100 meters a year as the average dispersion of female Meliponini in ocordance to data obtained from Trigona (tetragonisca) jaty F. SMITH and Melipona marginata LEP., while other species may give different values. For males the flying distance was roughly estimated to be 10 times that for females. A review of the bibliography on Meliponini swarm was made (pg. 43 to 47) and new facts added. The population desity (breeding population) corresponds in may species of Meliponini to one male and one female per 10.000 square meters. Apparently the males are more frequent than the females, because there are sometimes many thousands, of males in a swarm; but for the genie frequency the individuals which have descendants are the ones computed. In the case of Apini and Meliponini, only one queen per hive and the males represented by. the spermatozoos in its spermateca are computed. In Meliponini only one male mate with the queen, while queens of Apis mellijera L. are fecundated by an average of about 1, 5 males. (Roberts, 1944). From the date cited, one clearly sees that, on the whole, populations of wild social bees (Meliponini) are so small that the Sewall Wright effect may become of great importance. In fact applying the Wright's formula: f = ( 1/aN♂ + 1/aN♀) (1 - 1/aN♂ + 1/aN♀) which measures the fixation and loss of genes per generation, we see that the fixation or loss of genes is of about 7% in the more frequent species, and rarer species about 11%. The variation in size, tergite color, background color, etc, of Melipona marginata Lep. is atributed to this genetic drift. A detail, important to the survival of Meliponini species, is the Constance of their breeding population. This Constance is due to the social organization, i. e., to the care given to the reproductive individuals (the queen with its sperm pack), to the way of swarming, to the food storage intended to control variations of feeding supply, etc. 14) Some species of the Meliponini are adapted to various ecological conditions and inhabit large geographical areas (e. g. T. (Tetragonisca jaty F. SMITH), and Trigona (Nanno-trigona testaceicornis LEP.) while others are limited to narrow regions with special ecological conditions (e. g. M. fuscata me-lanoventer SCHWARZ). Other species still, within the same geographical region, profit different ecological conditions, as do M. marginata LEP. and M. quadrifasciata LEP. The geographical distribution of Melipona quadrifasciata LEP. is different according to the subspecies: a) subsp anthidio-des LEP. (represented in Fig. 7 by black squares) inhabits a region fron the North of the S. Paulo State to Northeastern Brazil, ,b) subspecies quadrifasciata LEP., (marked in Fig. 7 with black triangles) accurs from the South of S. Paulo State to the middle of the State of Rio Grande do Sul (South Brazil). In the margined region between these two areas of distribution, hi-brid colonies were found (Fig. 7, white circles); they are shown with more details in fig. 8, while the zone of hybridization is roughly indicated in fig. 9 (gray zone). The subspecies quadrifasciata LEP., has 4 complete yellow bands on the abdominal tergites while anthidioides LEP. has interrupted ones. This character is determined by one or two genes and gives different adaptative properties to the subspecies. Figs. 10 shows certains meteorological isoclines which have aproximately the same configuration as the limits of the hybrid zone, suggesting different climatic adaptabilities for both genotypes. The exis-tance of a border zone between the areas of both subspecies, where were found a high frequency of hybrids, is explained as follows: being each subspecies adapted to a special climatic zone, we may suppose a poor adaptation of either one in the border region, which is also a region of intermediate climatic conditions. Thus, the hybrids, having a combination of the parent qualities, will be best adapted to the transition zone. Thus, the hybrids will become heterotic and an equilibrium will be reached with all genotypes present in the population in the border region.
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Mangoes, cv. Imperial, were exposed, in post harvest, to the following methods of ripening: 1) sawdust burning; 2) alcohol vaporization; 3) calcium carbide (acetylene), 4) vapour of ethylene; and, 5) immersion in ethefon. All methods resulted in acceleration of ripening, when compared to controls. Calcium carbide, ethelene and ethefon were the best, methods. Alcohol vaporization also showed good results sawdust burning method showing low efficiency.
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The effects of growth substances on productivity of 'Davis' soybean maintained under competition was investigated. Before the flowering, Agrostemmin (1 g/10 ml/3 1), gibberellic acid (GA) 100 ppm, and (2-chloroethyl) trimethylammonium chloride (CCC) 2,000 ppm were applied. At the flower anthesis, 2,3,5-triiodobenzoic acid (TIBA) 20 ppm was applied. Other two applications with TIBA, with intervals of four days, were realized. The growth regulators did not affect the productivity of 'Davis' soybean maintened under competition. The competition among plants did not affect the stem dry weight and number of pods, and seeds. The competition reduced weight of pods without seeds, seed weight, and weight of 100 seeds.
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Otto-von-Guericke-Universtität Magdeburg, Fakultät für Wirtschaftswissenschaft, Univ., Dissertation, 2015
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The effect of intraspecific competition for food on larvae and of food deprivation for 24 h on 2nd and 4th instars of Ascia monuste orseis (Godart, 1819) was investigated. Intraspecific competition for food during the immature phase leads to long pupation time, high larval mortality, reduced adult weight, and reduced number of eggs per female. In food deprivation experiments, the major differences in A. monuste orseis performance were long pupation time in the group that was deprived during the 2nd instar; and a negative effect on reproduction in the group that was deprived during the 4th instar, with reduced adult weight. Both food deprived periods tested are critical, and deprivation during the 2nd instar seems to have an effect as drastic as during the 4th instar because it directly affects larvae survival. Immatures can resist food deprivation for 24 h during the 2nd and 4th instars (low mortality), have a compensatory behaviour (high ingestion and biomass gain) during the 5th instar, and do not demonstrate cannibalistic behaviour during food deprivation.