Ovarian follicular dynamics in Nelore breed (Bos indicus) cattle

The most common beef cattle raised in Brazil is the Nelore breed (Bos indicus). Information obtained by ultrasonography on follicular growth in Bos taurus cattle has been accumulating rapidly. However, there are few publications to date on follicular development in Bos indicus breeds. The follicular dynamics in Nelore heifers and cows during natural or prostaglandin (PG)-induced estrous cycle were studied. From the detection of estrus onward, all animals were examined daily by ultrasonography for one (n=35) or two (n=10) consecutive estrous cycles. The follicular dynamic in Nelore cattle was characterized by the predominance of 2 follicular waves in the cows (83.3%, n=18, P<0.05) and 3 waves in the heifers (64.7%, n=16, P<0.05). Most of the cattle observed over 2 consecutive estrous cycles presented the same pattern of follicular waves in the first and second cycle, and only 30% showed variation in the number of waves from one cycle to the other. Most of the follicular parameters analyzed were not affected by PG treatment or age but were altered by follicular waves. Consequently, data on cows and heifers were combined according to the number of follicular waves. The ovulatory follicle was larger than the other dominant follicles (P<0.05), and the ovulatory wave was shorter than the preceding waves (P<0.05). The interovulatory interval was longer in animals showing 3 waves than those exhibiting 2 waves (P<0.05). Maximum diameter of the dominant follicle (around 11 mm) and of the corpus luteum (CL, approximately 17 mm) were smatter than those reported for European breeds. In conclusion, the results demonstrate that although the dominant follicle and corpus luteum are smaller than in European breeds, the follicular dynamics in Nelore cattle were similar to those observed in European breeds and were characterized by 2 or 3 follicular waves for cows and heifers, respectively, during the natural or prostaglandin-induced estrous cycle. (C) 1997 by Elsevier B.V

Cohort profile: the Baependi Heart Study--a family-based, highly admixed cohort study in a rural Brazilian town

Purpose Cardiovascular disease (CVD) is a major challenge to global health. The same epidemiological transition scenario is replayed as countries develop, but with variations based on environment, culture and ethnic mixture. The Baependi Heart Study was set up in 2005 to develop a longitudinal family-based cohort study that reflects on some of the genetic and lifestyle-related peculiarities of the Brazilian populations, in order to evaluate genetic and environmental influences on CVD risk factor traits. Participants Probands were recruited in Baependi, a small rural town in the state of Minas Gerais, Brazil, following by first-degree and then increasingly more distant relatives. The first follow-up wave took place in 2010, and the second in 2016. At baseline, the study evaluated 1691 individuals across 95 families. Cross-sectional data have been collected for 2239 participants. Findings to date Environmental and lifestyle factors and measures relevant to cardiovascular health have been reported. Having expanded beyond cardiovascular health outcomes, the phenotype datasets now include genetics, biochemistry, anthropometry, mental health, sleep and circadian rhythms. Many of these have yielded heritability estimates, and a shared genetic background of anxiety and depression has recently been published. In spite of universal access to electricity, the population has been found to be strongly shifted towards morningness compared with metropolitan areas. Future plans A new follow-up, marking 10 years of the study, is ongoing in 2016, in which data are collected as in 2010 (with the exception of the neuropsychiatric protocol). In addition to this, a novel questionnaire package collecting information about intelligence, personality and spirituality is being planned. The data set on circadian rhythms and sleep will be amended through additional questionnaires, actimetry, home sleep EEG recording and dim light melatonin onset (DLMO) analysis. Finally, the anthropometric measures will be expanded by adding three-dimensional facial photography, voice recording and anatomical brain MRI

Losing the last feather: feather loss as an antipredator adaptation in birds

Birds often lose feathers during predation attempts, and this ability has evolved as a means of escape. Because predators are more likely to grab feathers on the rump and the back than on the ventral side of an escaping bird, we predicted that the former feathers would have evolved to be relatively loosely attached as an antipredator strategy in species that frequently die from predation. We estimated the force required to remove feathers from the rump, back, and breast by pulling feathers with a spring balance from a range of European bird species in an attempt to investigate ecological factors associated with ease of feather loss during predation attempts. The force required to loosen a feather from the rump was less than that required to loosen a feather from back, which in turn was less than that required to loosen a feather from the breast. The relative force needed to loosen rump feathers compared with feathers from the back and the breast was smaller for prey species preferred by the most common predator of small passerine birds, the sparrowhawk Accipiter nisus. Likewise, the relative force was also smaller in species with a high frequency of complete tail loss among free-living birds, which we used as an index of the frequency of failed predation attempts. The relative force required to remove feathers from the rump was smaller in species with a high frequency of fear screams, another measure of the relative importance of predation as a cause of death. Feather loss required particularly little force among solitarily breeding bird species that suffer the highest degree of predation. Antipredator defense in terms of force required to remove feathers from the rump was larger in species with a strong antiparasite defense in terms of T-cell--mediated immune response. These findings are consistent with the hypothesis that different defenses are antagonistic and that they are traded off against each other. Copyright 2006.alternative defense strategies; antagonistic defenses; immune defense; sociality

Electrical neuroimaging evidence that spatial frequency-based selective attention affects V1 activity as early as 40-60 ms in humans

<p>Abstract</p> <p>Background</p> <p>Karns and Knight (2009) <abbrgrp><abbr bid="B1">1</abbr></abbrgrp> demonstrated by using ERP and gamma band oscillatory responses that intermodal attention modulates visual processing at the latency of the early phase of the C1 response (62-72 ms) thought to be generated in the primary visual cortex. However, the timing of attentional modulation of visual cortex during object-based attention remains a controversial issue.</p> <p>Results</p> <p>In this study, EEG recording and LORETA source reconstruction were performed. A large number of subjects (29) and of trial repetitions were used (13,312). EEG was recorded from 128 scalp sites at a sampling rate of 512 Hz. Four square-wave gratings (0.75, 1.5, 3, 6 c/deg) were randomly presented in the 4 quadrants of the visual field. Participants were instructed to pay conjoined attention to a given stimulus quadrant and spatial frequency. The C1 and P1 sensory-evoked components of ERPs were quantified by measuring their mean amplitudes across time within 5 latency ranges 40-60, 60-80, 80-100, 100-120 and 120-140 ms.</p> <p>Conclusions</p> <p>Early attention effects were found in the form of an enhanced C1 response (40-80 ms) to frequency-relevant gratings. LORETA, within its spatial resolution limits, identified the neural generators of this effect in the striate cortex (BA17), among other areas.</p