O efeito das altas temperaturas na resistência à compressão de um betão com adição de fibras de aço e têxteis recicladas de pneu

O betão é um dos materiais responsáveis pelo aumento do consumo de cimento e agregados naturais na construção civil, levantando questões de sustentabilidade dos recursos naturais. Este facto conduz à necessidade de desenvolver tecnologias inovadoras e materiais alternativos para melhorar não só o nível de desempenho do betão mas, acima de tudo, apoiar a política de proteção ambiental. O objetivo deste trabalho é demonstrar, através de investigação experimental, que a adição de fibras de aço e têxteis provenientes da reciclagem de pneus é viável para produzir um betão com um comportamento satisfatório à temperatura ambiente e quando submetido a elevadas temperaturas.info:eu-repo/semantics/publishedVersio

Betão com adição de fibras de aço e têxteis reciclados de pneu sujeito a altas temperaturas

O betão é um dos materiais responsáveis pelo aumento do consumo de cimento e agregados naturais na construção civil, levantando questões de sustentabilidade dos recursos naturais. Este facto conduz à necessidade de desenvolver tecnologias inovadoras e materiais alternativos para melhorar não só o nível de desempenho do betão mas, acima de tudo, apoiar a política de proteção ambiental. O objetivo deste trabalho é demonstrar, através de investigação experimental, que a adição de fibras têxteis e de fibras de aço provenientes da reciclagem de pneus é viável para produzir um betão com um comportamento satisfatório quando submetido a elevadas temperaturas.info:eu-repo/semantics/publishedVersio

Listeria species as contaminants of lettuce and its resistant genes in Benin city, Nigeria

This study was aimed at determining the level of Listeria contaminants and subsequently detects some resistance genes among the isolated Listeria species from lettuce sold in some vegetable markets in Benin City, Nigeria. Twenty-four lettuce samples were purchased from three vegetable markets in Benin City, Nigeria and examined using standard microbiological methods. Microbial characterization revealed Listeria monocytogenes and L. grayi as the predominant species isolated. Plate count analysis on Listeria selective agar revealed that lettuce sold in Oba market and Forestry market had the highest and lowest mean count of Listeria species 224.00 x 102 CFU/g and 83.00 x 102 CFU/g respectively. Most (63.75%) of the Listeria species isolates were found to be susceptible to Ofloxacin (5 μg), Ciprofloxacin (10 μg), Streptomycin (10 μg), Gentamycin (10 μg), Pefloxacin (5 μg) whereas species harbouring tetracycline (65%) and erythromycin (60%) resistant genes. The study provides an evidence of the colonization of Listeria species in lettuce sold in Benin City which may pose serious public health threat to the populace.Keywords: Listeria monocytogenes, Listeria grayi, Lettuce, Resistance gene

Assessment of foveal and extra-foveal photostress recovery time in primary open angle glaucoma

Photostress recovery time (PSRT) is a clinical procedure that measures the amount of time required for the macular to return to its normal level of function after being exposed to a bright light source. This study was a case control clinical study carried out to measure the foveal and extra-foveal photo stress recovery time in participants with primary open angle glaucoma. Fifty five subjects, 24 with primary open angle glaucoma with a mean age of 34.38±12.19 and 31 control subjects with a mean age of 26.58±7.23 were used in this study. The mean photostress recovery time measured on the fovea, 7o nasal, temporal, inferior and superior to the fovea were, 62.38±4.67, 8.71±7.19, 11.23±10.96, 12.08±8.96 and 12.44±9.30 respectively for subjects with primary open angle glaucoma. For the control subjects, the mean photostress recovery time measured on the fovea, 7o nasal, temporal, inferior and superior to the fovea were 23.29±1.63 11.89±8.62, 11.53±8.19, 12.89±8.67 and 13.60±8.36 respectively. Analysis with SPSS version 21 using the two factor ANOVA showed a significant difference (P<0.05) in photostress recovery time 7o nasally, temporally, inferiorly and superior to the fovea between primary open angle glaucoma subjects and a control group. Data analysis with the independent sample t-test also showed a significant difference (P<0.05) in photostress recovery time on the fovea between primary open angle glaucoma subjects and a control group. In conclusion, primary open angle glaucoma alters the photostress recovery time, both on the fovea and extra-foveal region of the retina. Photostress recovery test should be included in the routine eye examination of patients.Keywords: Primary Open angle glaucoma, Photostress recovery time, foveal, extra-fovea

Model predictive current control based on a generalised adjacent voltage vectors approach for multilevel inverters

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163810/1/pel2bf01679.pd

Cdk Activity Couples Epigenetic Centromere Inheritance to Cell Cycle Progression

Centromeres form the site of chromosome attachment to microtubules during mitosis. Identity of these loci is maintained epigenetically by nucleosomes containing the histone H3 variant CENP-A. Propagation of CENP-A chromatin is uncoupled from DNA replication initiating only during mitotic exit. We now demonstrate that inhibition of Cdk1 and Cdk2 activities is sufficient to trigger CENP-A assembly throughout the cell cycle in a manner dependent on the canonical CENP-A assembly machinery. We further show that the key CENP-A assembly factor Mis18BP1(HsKNL2) is phosphorylated in a cell cycle-dependent manner that controls its centromere localization during mitotic exit. These results strongly support a model in which the CENP-A assembly machinery is poised for activation throughout the cell cycle but kept in an inactive noncentromeric state by Cdk activity during S, G2, and M phases. Alleviation of this inhibition in G1 phase ensures tight coupling between DNA replication, cell division, and subsequent centromere maturation.FCT doctoral fellowship: (SFRH/BD/33219/2007); FCT grant: (BIA-BCM/100557/2008); Fundação Calouste Gulbenkian; European Commission FP7 programme; EMBO installation grant

Optogenetic stimulation of the cochlear nucleus using channelrhodopsin-2 evokes activity in the central auditory pathways

Optogenetics has become an important research tool and is being considered as the basis for several neural prostheses. However, few studies have applied optogenetics to the auditory brainstem. This study explored whether optical activation of the cochlear nucleus (CN) elicited responses in neurons in higher centers of the auditory pathway and whether it elicited an evoked response. Viral-mediated gene transfer was used to express channelrhodopsin-2 (ChR2) in the mouse CN. Blue light was delivered via an optical fiber placed near the surface of the infected CN and recordings were made in higher-level centers. Optical stimulation evoked excitatory multiunit spiking activity throughout the tonotopic axis of the central nucleus of the inferior colliculus (IC) and the auditory cortex (Actx). The pattern and magnitude of IC activity elicited by optical stimulation was comparable to that obtained with a 50 dB SPL acoustic click. This broad pattern of activity was consistent with histological confirmation of green fluorescent protein (GFP) label of cell bodies and axons throughout the CN. Increasing pulse rates up to 320 Hz did not significantly affect threshold or bandwidth of the IC responses, but rates higher than 50 Hz resulted in desynchronized activity. Optical stimulation also evoked an auditory brainstem response, which had a simpler waveform than the response to acoustic stimulation. Control cases showed no responses to optical stimulation. These data suggest that optogenetic control of central auditory neurons is feasible, but opsins with faster channel kinetics may be necessary to convey information at rates typical of many auditory signals

Faith-based approach to improve menstrual hygiene management (MHM): challenges and successes

This paper examines faith-based organisations’ (FBOs) essential and effective approach to breaking the myths and silence surrounding menstruation, the provision of comprehensive menstrual information, menstrual hygiene management (MHM) and the assessment of an initiative integrating FBOs into the structure for shattering taboos around menstruation. Whereas substantial progress has been made to evolve more decent and socially acceptable approaches to MHM in recent times, the active role of FBOs in accelerating and enhancing better MHM has not been properly appraised or harnessed in Nigeria. As an integral part of the nascent collaboration between Daniel Iroegbu Global Health Foundation and Second Chance Initiative this synergic thrust is reaching FBOs to discuss this gap in MHM programming and seek newer realities in MHM. Addressing taboos and silence around menstruation requires a multi-sect oral collaboration and response similar to the approach currently in use for HIV/AIDS and Malaria morbidity response and control in Nigeria

Disparate Population and Holobiont Structure of Pocilloporid Corals Across the Red Sea Gradient Demonstrate Species-Specific Evolutionary Trajectories

Global habitat degradation heightens the need to better understand patterns of genetic connectivity and diversity of marine biota across geographical ranges to guide conservation efforts. Corals across the Red Sea are subject to pronounced environmental differences, but studies so far suggest that animal populations are largely connected, excepting evidence for a genetic break between the northern-central and southern regions. Here, we investigated population structure and holobiont assemblage of two common pocilloporid corals, Pocillopora verrucosa and Stylophora pistillata, across the Red Sea. We found little evidence for population differentiation in P. verrucosa, except for the southernmost site. Conversely, S. pistillata exhibited a complex population structure with evidence for within-reef and regional genetic differentiation, in line with differences in their reproductive mode (P. verrucosa is a broadcast spawner and S. pistillata is a brooder). Analysis for genomic loci under positive selection identified 85 sites (18 of which were in coding sequences) that distinguished the southern P. verrucosa population from the remainder of the Red Sea population. By comparison, we found 128 loci (24 of which were residing in coding sequences) in S. pistillata with evidence for local adaptation at various sites. Functional annotation of the underlying proteins revealed putative roles in the response to stress, lipid metabolism, transport, cytoskeletal rearrangement, and ciliary function (among others). Microbial assemblages of both coral species showed pervasive association with microalgal symbionts from the genus Symbiodinium (former clade A) and bacteria from the genus Endozoicomonas that exhibited significant differences according to host genotype and environment. The disparity of population genetic and holobiont assemblage patterns even between closely related species (family Pocilloporidae) highlights the need for multispecies investigations to better understand the role of the environment in shaping evolutionary trajectories. It further emphasizes the importance of networks of reef reserves to achieve conservation of genetic variants critical to the future survival of coral ecosystems

Compaction of Rods: Relaxation and Ordering in Vibrated, Anisotropic Granular Material

We report on experiments to measure the temporal and spatial evolution of packing arrangements of anisotropic, cylindrical granular material, using high-resolution capacitive monitoring. In these experiments, the particle configurations start from an initially disordered, low-packing-fraction state and under vertical vibrations evolve to a dense, highly ordered, nematic state in which the long particle axes align with the vertical tube walls. We find that the orientational ordering process is reflected in a characteristic, steep rise in the local packing fraction. At any given height inside the packing, the ordering is initiated at the container walls and proceeds inward. We explore the evolution of the local as well as the height-averaged packing fraction as a function of vibration parameters and compare our results to relaxation experiments conducted on spherically shaped granular materials.Comment: 9 pages incl. 7 figure