Effect of Gait Imagery Tasks on Lower Limb Muscle Activity With Respect to Body Posture

The objective of this study was to evaluate the effect of gait imagery tasks on lowerlimb muscle activity with respect to body posture. The sitting and standing position and lower limb muscle activity were evaluated in 27 healthy female students (24.4±1.3 years, 167.2±5.2 cm, 60.10±6.4 kg). Surface electromyography was assessed during rest and in three different experimental conditions using mental imagery. These included a rhythmic gait, rhythmic gait simultaneously with observation of a model, and rhythmic gait after performing rhythmic gait. The normalized root mean square EMG values with respect to corresponding rest position were compared using non-parametric statistics. Standing gait imagery tasks had facilitatory effect on proximal lower limb muscle activity. However, electromyography activity of distal leg muscles decreased for all gait imagery tasks in the sitting position, when the proprioceptive feedback was less appropriate. For subsequent gait motor imagery tasks, the muscle activity decreased, probably as result of habituation. In conclusion, the effect of motor imagery on muscle activity appears to depend on relative strength of facilitatory and inhibitory inputs

Selection at the Y Chromosome of the African Buffalo Driven by Rainfall

Selection coefficients at the mammalian Y chromosome typically do not deviate strongly from neutrality. Here we show that strong balancing selection, maintaining intermediate frequencies of DNA sequence variants, acts on the Y chromosome in two populations of African buffalo (Syncerus caffer). Significant correlations exist between sequence variant frequencies and annual rainfall in the years before conception, with five- to eightfold frequency changes over short time periods. Annual rainfall variation drives the balancing of sequence variant frequencies, probably by affecting parental condition. We conclude that sequence variants confer improved male reproductive success after either dry or wet years, making the population composition and dynamics very sensitive to climate change. The mammalian Y chromosome, interacting with ecological processes, may affect male reproductive success much more strongly than previously thought

Diagnóstico ultra-sonográfico do momento ovulatório em búfalas (Bubalus bubalis) inseminadas no estro espontâneo e induzido Ultrasonographical diagnosis of ovulation in buffaloes (Bubalus Bubalis) inseminated in spontaneous and induced oestrus

O objetivo deste experimento foi determinar o intervalo entre o início do estro induzido ou espontâneo e a ovulação em fêmeas bubalinas (Bubalus bubalis) com o auxílio da ultra-sonografia, o que permitirá a determinação de um horário mais apropriado para a I.A. pré-fixada. Nos meses de março a junho, outono no sul do Brasil (época reprodutiva dos bubalinos), 132 fêmeas adultas ciclando foram divididas em 3 grupos experimentais: Grupo A - 53 fêmeas foram tratadas com implante subcutâneo de Norgestomet ou espiral intravaginal contendo progesterona. Na retirada dos dispositivos, foi aplicado 250mg de cloprostenol pela via intra-submucosa vulvar (i.s.m.v.), Grupo B - 48 búfalas foram tratadas com dupla aplicação de 250mg de cloprostenol pela via i.s.m.v. com intervalo de 11 dias e Grupo C - 31 búfalas foram consideradas testemunhas, sem tratamento. Todas as búfalas foram inseminadas no momento da observação do maior diâmetro do folículo pré-ovulatório, detectado por ultra-sonografia, durante o estro. Após o diagnóstico de prenhez, constatou-se, nos três tratamentos, que houve diferença significativa entre as búfalas prenhes e vazias no período compreendido entre o início do estro até o momento da ovulação e no período entre a I.A.e a ovulação. Os índices de prenhez foram de 41,5%, 52,1% e 54,8% nos grupos A, B e C, respectivamente. A variação no intervalo estro-ovulação nas búfalas é uma barreira para a obtenção de taxas de prenhez por I.A. pré-fixada comparáveis à monta natural, tanto no estro induzido através de progesterona e prostaglandina F2 alfa como no estro espontâneo.<br>The aim of this experiment was to determine the interval between the beginning of the spontaneous or induced oestrus and the ovulation in females buffaloes using ultrasonography. This will be useful in the determination of the most proper moment for the pre-fixed artificial insemination. In the reproductive season, autumn in the South of Brazil (march-june), 132 clicling females were divided in 3 groups: Group A: 53 females were treated with auricular subcutaneous implant of norgestomet or intravaginal device of progesterone. In the moment that the devices were removed, 250mg of cloprostenol were applied for intravulvar submucosis (ivsm). Group B: 48 buffaloes females were treated twice with 250mg of cloprostenol for ivsm with interval of 11 days. Group C: 31 buffaloes females remained without any treatment (control group). All of them were inseminated in the moment that was observed the biggest diameter of pre-ovulatory follicle determinated by ultrasonography. In the 3 groups, there was significative difference between pregnant and non-pregnant females in the oestrus-ovulation interval and in the A.I.-ovulation interval. The pregnancy rates were 41.5%, 52.1% and 54.8% in the groups A, B amd C, respectively. The variation in the oestrus-ovulation in buffaloes is the major obstacle to achieve high pregnancy rates using pre-fixed artificial insemination in spontaneous and induced oestrus