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Bos taurus taurus and Bos taurus indicus cattle subspecies present different capabilities in coping with situations of elevated temperatures, the latter being more tolerant to heat stress. Thus, some breeding programs crossed these subspecies to produce a high producing yet heat-tolerant breed (Girolando). Nineteen Holstein (H100) and 19 Girolando cows [(½ Holstein × Gir (H50) and ¾ Holstein × Gir (H75)] with similar milk production were used in a six-day experiment to evaluate the consequences of heat stress due to shade deprivation on their physiological, blood and milk traits. Cows were exposed to a non-shaded environment between morning (06:00h; GMT -3:00) and evening milking (14:30h; GMT -3:00) with access to water ad libitum. Procedures were conducted before morning and evening milkings. Physiological parameters related to mechanisms of heat dissipation were measured, as well as the milk composition. Blood traits were evaluated. The temperature-humidity index (THI) was calculated. Statistical procedures included analysis of variance, correlation, and principal factors. THI was elevated during the trial and negatively impacted physiological, milk, and blood parameters in H100, H75, and H50. Alterations in physiology, milk stability, milk composition, and blood traits were more pronounced in H100. Holstein cows presented changes in physiological parameters in a more pronounced manner and in some milk and blood traits related to the reduced capability of this breed in dealing with elevated THI. The similarity in milk production levels excludes this parameter as a justification for differences in heat tolerance, with genetic composition being the main reason for these results. Made available in DSpace on 2021-11-25T12:04:23Z (GMT). No. of bitstreams: 1 Elevated-temperature-humidity.pdf: 761551 bytes, checksum: 0e2950a57ff402580f102316e5cd8df9 (MD5) Previous issue date: 2021

This article explores some dominant trends in teaching classical electromagnetic (EM) field theory in electrical engineering (EE) undergraduate curricula. The acronym EM will be used interchangeably to designate either electromagnetic or electromagnetism. The intended significance will be evident from the context.

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Made available in DSpace on 2017-11-20T23:31:34Z (GMT). No. of bitstreams: 1 Cnpgl2017RevBrasZootInfrared.pdf: 1742584 bytes, checksum: 140e37615fe7436aac110ed6a92a7b29 (MD5) Previous issue date: 2017-11-20

The multimeric membrane protein complex translocase mediates the transport of preproteins across and integration of membrane proteins into the inner membrane of Escherichia coli. The translocase consists of the peripheral membrane-associated ATPase SecA and the heterotrimeric channel-forming complex consisting of SecY, SecE and SecG. We have investigated the quaternary structure of the SecYEG complex in proteoliposomes. Fluorescence resonance energy transfer demonstrates that SecYEG forms oligomers when embedded in the membrane. Freeze-fracture techniques were used to examine the oligomeric composition under non-translocating and translocating conditions. Our data show that membrane-embedded SecYEG exists in a concentration-dependent equilibrium between monomers, dimers and tetramers, and that dynamic exchange of subunits between oligomers can occur. Remarkably, the formation of dimers and tetramers in the lipid environment is stimulated significantly by membrane insertion of SecA and by the interaction with translocation ligands SecA, preprotein and ATP, suggesting that the active translocation channel consists of multiple SecYEG complexes. (c) 2005 Elsevier Ltd. All rights reserved.

Summary Pluripotent stem cells can self-renew in culture and differentiate along all somatic lineages in vivo. While much is known about the molecular basis of pluripotency, the mechanisms of differentiation remain unclear. Here, we profile individual mouse embryonic stem cells as they progress along the neuronal lineage. We observe that cells pass from the pluripotent state to the neuronal state via an intermediate epiblast-like state. However, analysis of the rate at which cells enter and exit these observed cell states using a hidden Markov model indicates the presence of a chain of unobserved molecular states that each cell transits through stochastically in sequence. This chain of hidden states allows individual cells to record their position on the differentiation trajectory, thereby encoding a simple form of cellular memory. We suggest a statistical mechanics interpretation of these results that distinguishes between functionally distinct cellular “macrostates” and functionally similar molecular “microstates” and propose a model of stem cell differentiation as a non-Markov stochastic process., Graphical Abstract, Highlights • We profile individual stem cells as they differentiate along the neural lineage • Regulatory network changes and increased cell variability accompany differentiation • Analysis of dynamics with a hidden Markov model reveals unobserved molecular states • We propose a model of stem cell differentiation as a non-Markov stochastic process, We profile individual mouse embryonic stem cells as they progress along the neuronal lineage. Analysis of observed cell dynamics using a hidden Markov model reveals the presence of a chain of unobserved molecular states that each cell transits through stochastically in sequence. We suggest a statistical mechanics interpretation of these results and propose a model of stem cell differentiation as a non-Markov stochastic process.

The objective of this work was to evaluate the inclusion of sodium citrate and sodium bicarbonate in the diet of lactating Jersey cows, and its effects on the metabolic attributes, productivity and stability of milk. We evaluated urinary pH, levels of glucose and urea in blood, body weight, body condition score, milk yield, milk stability (ethanol test), and milk physicochemical properties of 17 cows fed diets containing sodium citrate (100 g per cow per day), sodium bicarbonate (40 g per cow per day) or no additives. Assessments were made at the 28th and 44th days. Supply of sodium citrate or bicarbonate has no influence on the metabolic attributes, productivity, body weight, and body condition score of the cows, neither on the composition and stability of milk. Made available in DSpace on 2013-09-10T00:30:48Z (GMT). No. of bitstreams: 1 Stumpf2013PAB.pdf: 416394 bytes, checksum: 8337a7adbe68eaf3679351ee295ff871 (MD5) Previous issue date: 2013-09-06 Notas científicas.

p97 (VCP or valosin containing protein in mammals and Cdc48p in yeast) is a ubiquitously expressed and evolutionarily highly conserved hexameric member of the magnesium-dependent Walker P-loop AAA-ATPases. p97 has been associated with various essential cellular processes including ubiquitin-proteasome[for full text, please go to the a.m. URL], 57th Annual Meeting of the German Society for Neuropathology and Neuroanatomy (DGNN)

Current atmospheric models cannot reproduce some of the characteristics of the transition between the L dwarfs with cloudy atmospheres and the T dwarfs with dust-depleted photospheres. It has been proposed that a majority of the L/T transition brown dwarfs could actually be a combinaison of a cloudy L dwarf and a clear T dwarf. Indeed binarity seems to occur more frequently among L/T transition brown dwarfs. We aim to refine the statistical significance of the seemingly higher frequency of binaries. Co-eval binaries would also be interesting test-beds for evolutionary models. We obtained high-resolution imaging for six mid-L to late-T dwarfs, with photometric distances between 8 and 33pc, using the adaptive optics systems NACO at the VLT, and the Lick system, both with the laser guide star. We resolve none of our targets. Combining our data with published results, we obtain a frequency of resolved L/T transition brown dwarfs of (31+21-15)%, compared to (21+10-7)% and (14+14-7)% for mid-L and T dwarfs (90% of confidence level). These fractions do not significantly support, nor contradict, the hypothesis of a larger binary fraction in the L/T transition. None of our targets has companions with effective temperatures as low as 360-1000K at separations larger than 0.5"., 6 pages, 4 figures, accepted by A&A