Modulation of rumen pH by sodium bicarbonate and a blend of different sources of magnesium oxide in lactating dairy cows submitted to a concentrate challenge

With the objective of evaluating the potential effects of sodium bicarbonate or a magnesium-based product on rumen pH and milk performance of dairy cattle exposed to a dietary challenge, 30 lactating Holstein cows (648 ± 67 kg of body weight; 44.4 ± 9.9 kg/d of milk yield; 155 ± 75 d in milk) were blocked by parity (9 primiparous and 21 multiparous) and randomly distributed to 3 treatment groups. One group received a total mixed ration (TMR) that acted as a control (CTR), a second group (SB) received the same TMR but with an additional supplementation of 0.8% of sodium bicarbonate, and a third group (MG) received the same TMR as CTR but an additional supplementation of 0.4% of a magnesium-based product (pHix-Up, Timab, Dinard, France). After 1 wk of exposure to this TMR, all 3 rations were supplemented with 1 kg/d of barley, which was then increased 1 kg/wk until reaching 3 kg/d of barley during wk 4 of the study. Every kilogram of barley replaced 1 kg of forage in the diet. Individual feed intake and behavior were monitored using electronic feed bins. Seven cows per treatment were equipped with an intraruminal bolus that recorded pH every 15 min. As the severity of the barley challenge increased, dry matter intake decreased, but this decrease was more pronounced in SB cows than in MG cows, with an intermediate response for CTR cows. The MG cows produced more milk when challenged with 2 or 3 kg/d of additional barley than when challenged with 1 kg/d, whereas CTR cows produced less milk with the 3 kg/d challenge compared with 1 or 2 kg/d, and the SB cows maintained milk production. Milk fat content decreased with barley challenges, with CTR cows experiencing a more severe decrease than SB cows, which maintained stable butterfat values throughout the study, and MG cows showed a decline in milk fat content only with the 3 kg/d of additional barley. Meal size was also reduced as the severity of barley challenge increased, and this reduction was more modest in MG cows than in SB cows. The number of daily meals consumed by SB and MG cows was more constant than that recorded in CTR cows. Cows on the CTR and SB treatments showed a marked decrease in rumen pH with the 3 kg/d of additional barley, whereas MG cows maintained stable rumen pH during the barley challenges and had greater average rumen pH (5.93 ± 0.04) than CTR cows (5.83 ± 0.04) with the 3 kg/d of additional barley; SB cows showed intermediate values (5.85 ± 0.04). Last, MG cows spent less time (32.3 ± 6.1%) with rumen pH ≤5.8 when exposed to the 3 kg/d of barley challenge than CTR and SB cows (50.7 ± 5.02%). In conclusion, supplementation with MG prevents the decline in dry matter intake and milk production induced by a rumen challenge, whereas supplementation with SB prevents the decay in milk production but does not prevent the decrease in feed intake. These changes were probably due to the ability of the MG treatment to prevent a reduction in rumen pH when challenging cows with 3 kg/d of additional barley in the ration.     

Host Restriction Factors Modulating HIV Latency and Replication in Macrophages

In addition to CD4⁺ T lymphocytes, myeloid cells and, particularly, differentiated macrophages are targets of human immunodeficiency virus type-1 (HIV-1) infection via the interaction of gp120Env with CD4 and CCR5 or CXCR4. Both T cells and macrophages support virus replication, although with substantial differences. In contrast to activated CD4⁺ T lymphocytes, HIV-1 replication in macrophages occurs in nondividing cells and it is characterized by the virtual absence of cytopathicity both in vitro and in vivo. These general features should be considered in evaluating the role of cell-associated restriction factors aiming at preventing or curtailing virus replication in macrophages and T cells, particularly in the context of designing strategies to tackle the viral reservoir in infected individuals receiving combination antiretroviral therapy. In this regard, we will here also discuss a model of reversible HIV-1 latency in primary human macrophages and the role of host factors determining the restriction or reactivation of virus replication in these cells.     

Putrescine: A Key Metabolite Involved in Plant Development,Tolerance and Resistance Responses to Stress

Putrescine (Put) is the starting point of the polyamines (PAs) pathway and the most common PA in higher plants. It is synthesized by two main pathways (from ornithine and arginine), but recently a third pathway from citrulline was reported in sesame plants. There is strong evidence that Put may play a crucial role not only in plant growth and development but also in the tolerance responses to the major stresses affecting crop production. The main strategies to investigate the involvement of PA in plant systems are based on the application of competitive inhibitors, exogenous PAs treatments, and the most efficient approaches based on mutant and transgenic plants. Thus, in this article, the recent advances in understanding the role of this metabolite in plant growth promotion and protection against abiotic and biotic stresses will be discussed to provide an overview for future research.     

Direct employment in the wind energy sector: An EU study

Wind energy is often said to have positive effects on employment, but few studies have systematically dealt with this matter. This article presents estimates of direct wind energy employment in all EU countries, gathered for the first time. By using a thematic survey, the authors have been able to analyse aspects such as gender distribution, company profiles and the shortage of skilled workers reported by wind energy companies. The outcomes show that wind energy deployment creates a significant number of jobs (over 104,000 in 2008), and does so at a time when other energy sectors are shrinking. There is a clear relationship between MW installed and number of jobs, but the use of a single EU job/MW ratio is not feasible, due to differences in the export/import capacity. Wind turbine manufacturers—including major sub-components—are responsible for the lion's share of the jobs, and there is a marked prevalence of males in the workforce. The scarcity of specialist roles—project managers, engineers and O&M technicians—is not likely to be solved unless a series of educational, mobility and dissemination measures are put into practice.     

Hydrogen photocatalytic production from the self-assembled films of PAH/PAA/TiO2 supported on bacterial cellulose membranes

The issues related to renewable energy sources is a matter of great worldwide appeal due to the increasing energy demand, instability in oil prices and environmental problems. In this context, the purpose of this study was to prepare self-assembled films of polyallylamine hydrochloride and poly (acrylic acid) supported onto bacterial cellulose membranes by a layer-by-layer approach with titanium dioxide (TiO₂) nanoparticles and different concentrations of gold for application in hydrogen gas (H₂) production by photocatalysis. The influence of the gold concentration and the presence and size of the gold nanoparticles (Au NPs), as well as the surface and thickness of the films on H₂ production was investigated. The results showed that the film, prepared with a lower concentration of gold, presented the smallest Au NPs and, therefore, greater contact with the TiO₂ nanoparticle surfaces, producing more H₂. By analyzing the variation in all the experimental parameters used in the preparation of the films, it can be concluded that the best H₂ production achieved was 29.12 μmol h^?1 cm².     

Parameters effect on proton conductivity to obtain chitosan membranes for use as electrolytes in PEMFC

The chitosan biopolymer can be used as a proton‐conducting membrane in proton‐exchange membrane fuel cell. In the forms that they have normally obtained and tested, chitosan membranes typically show poor performance in conduction of protons, requiring modifications in the structure of the biopolymer or blending with other polymers to increase its proton conductivity. The present work investigates the individual properties of chitosan and relates them to the proton conductivity performance of membranes composed of this polymer. Evaluation was made of the effects of variables such as the degree of deacetylation (DD) and the molar mass (Mv) of chitosan membranes without addition of any other polymer. The DD and Mv values of the chitosan used to produce membranes determined the proton conduction, with lower DD and higher Mv resulting in higher conductivity. The thicker membranes presented greater crystallinity, with conductivity between 2.0 × 10^?4 and 1.8 × 10^?3 S cm^?1. The characteristic stages of degradation of the chitosan membranes were in the ranges 200 to 300°C and 500 to 600°C, indicating good thermal stability of the material.     

Linking entrepreneurial orientation to project success

Entrepreneurial orientation (EO) is a strategic posture of an organization, and it is related to basic policies and practices for the development of entrepreneurial actions looking for creating competitive advantages. This study develops and tests a model of the relationship between entrepreneurial orientation and project success in Brazilian context. As quantitative research, a survey was used to collect data. A sample of 100 valid answers from project practitioners was treated through the structural equation modeling method. As research implications, the main result points out the positive correlation between the entrepreneurial orientation and the project success, contributing to the development of this research subject and helping to minimize the gap in the literature that addresses the relationship between project success and EO. In practical terms, understanding that innovativeness, risk taking, proactiveness, autonomy and competitive aggressiveness (the dimensions of the EO) can contribute to project success and can also indirectly impact on organizational performance, could help organizations get competitive advantage when developing correlate factors. Finally, the results suggest that practices of project management can be aligned to the firm's entrepreneurial orientation to enable firms to attain better results in their projects and generate a competitive advantage. On other hand, given the proportion of the impact of EO on project success (20.3%) identified in this study, it is critical that project management professionals expand their horizon to recognize other factors that affect project success.     

Antibiofilm activity of the essential oil of citronella (Cymbopogon nardus) and its major component,geraniol, on the bacterial biofilms of Staphylococcus aureus

Food Science and Biotechnology - Medicinal plants with antimicrobial action have been investigated for uses against biofilms, among which, Cymbopogon nardus, citronella, stands out as a promising...     

Relationship between solar radiation and surface distribution of vegetation in Fildes Peninsula and Ardley Island,Maritime Antarctica

The aim of this work is to produce a simplified vegetation map of ice-free areas of the Fildes Peninsula (FP) and Ardley Island (AI) thought object-oriented classification using a QuickBird satellite image and to evaluate the influence of the global solar radiation (GSR) over the vegetation distribution. The vegetation data were generated from multiresolution segmentation using the panchromatic and infrared layers, and for the classification we calculated the normalized vegetative difference index (NVDI) and the green NVDI. Two classes were created – Lichen and Moss Cushion SubFormation and Moss Subformation – with 48 vegetation samples collected on surveys during the austral summers of 2008 and 2009. We used a kappa index to evaluate the classification efficiency using 100 sampled points obtained in austral summer of 2013. The GSR was estimated, and in order to evaluate the effect of meteorological phenomena and cloudless, we measured the GSR using a net radiometer model CNR4 installed in FP between 2014 and 2016. The estimate of GSR was done for seasons of 2015, in order to estimate the light compensation point and the saturation point for the plant communities in FP and AI. The kappa index was 0.73 and the global accuracy was 0.78, showing consistency between the classification and ground truth. The area was covered by vegetation in FP was 16.7% and in AI is 59.1%. The vegetation cover is distributed differently at FP and AI, and our results suggest GSR plays an important role in vegetation distribution and these tendencies could be related to greater GSR demand by mosses when compared to lichens.     

Towards the development of technical specifications for the production of lithium–lead alloys for the ITER HCLL TMB

The ITER and DEMO projects are developing new Test Blanket Modules (TBM), where the Pb–Li alloy plays a key role in the new commercial fusion reactors functionality. The Breeding Blanket (BB) has to perform several functions which are essential for the reactor operation. The HCLL TBM is one of the Breeding Blanket concepts to be tested in ITER. It is cooled by He and uses the eutectic liquid metal LLE (Lithium–Lead Eutectic) as breeder material (enriched at 90% in ⁶Li).Pb–Li eutectic alloy has no known uses outside of fusion technology, so the available databases of this material are currently incomplete. It is very important, within the material specifications, to have a complete characterization in order to define their chemical and physical properties, because any variation in the alloy composition has significant consequences in their behaviour, and therefore in their regenerative function inside the blanket.The chemical characterization methodology developed and presented in this paper (useful for both Pb–Li alloys as any Pb alloy) is a key tool that allows performing standard quality control procedures for base material and/or monitoring the alloy during the reactor operation. This report provides a procedure to perform a wide material chemical characterization, assessing the concentrations of major elements, as well as a review of trace level elements that can be found both in the eutectic alloy and in starting materials. In this determination plays an important role the ICP-MS technique because, as a highly sensitive technique, allows very low detection limits.