3,257 research outputs found
Extending flood damage assessment methodology to include sociological and environmental dimensions
Optimal and sustainable flood plain management, including flood control, can only be achieved when the impacts of flood control measures are considered for both the man-made and natural environments, and the sociological aspects are fully considered. Until now, methods/models developed to determine the influences of floods and flood control measures in South Africa, and elsewhere in the world, focus on the man-made environment and neglect the natural environment and social dimensions. Two models, recently completed in South Africa, namely FLODSIM (flood damage simulation model for irrigation areas) and TEWA (flood damage simulation model for urban areas) are cases in point. This paper gives an overview of the development of flood damage assessment and mitigation methodology in South Africa. Emphasis is placed on the evolution from the traditional ex-post approach to the latest ex-ante approach in which the sociological and natural environmental dimensions are included. Deliverables from the presentation should be of value to researchers and managers in the fields of flood management and environmental impact assessment worldwide.
WaterSA Vol.27(4) 2001: 517-52
Loss functions for structural flood mitigation measures
The paper aims at discussing the methodology used to develop loss functions for flood mitigation measures, using historic data of flood damage to infrastructure. The main determinants of the extent of damage are the size of the flood and the length of the infrastructure within the boundaries of the flood-line. In regression analysis, flood peak was used as the independent variable in the Cobb-Douglas functions to depict the relationship between damage and flood peak. The Mfolozi flood-plain in Northern KwaZulu-Natal served as the study area. Loss functions for infrastructure, for ex ante estimation of damage to infrastructure, were developed for inclusion in a flood damage simulation model (FLODSIM) developed by the Department of Agricultural Economics of the University of the Orange Free State in collaboration with the Water Research Commission. Loss functions were determined for spillways, levees, tramlines, public roads, drains and bridges.
WaterSA Vol.27(1) 2001: 35-3
Quantum Hall effect and Landau level crossing of Dirac fermions in trilayer graphene
We investigate electronic transport in high mobility (\textgreater 100,000
cm/Vs) trilayer graphene devices on hexagonal boron nitride, which
enables the observation of Shubnikov-de Haas oscillations and an unconventional
quantum Hall effect. The massless and massive characters of the TLG subbands
lead to a set of Landau level crossings, whose magnetic field and filling
factor coordinates enable the direct determination of the
Slonczewski-Weiss-McClure (SWMcC) parameters used to describe the peculiar
electronic structure of trilayer graphene. Moreover, at high magnetic fields,
the degenerate crossing points split into manifolds indicating the existence of
broken-symmetry quantum Hall states.Comment: Supplementary Information at
http://jarilloherrero.mit.edu/wp-content/uploads/2011/04/Supplementary_Taychatanapat.pd
Exercise capacity in patients with repaired Tetralogy of Fallot aged 6 to 63 years
OBJECTIVES: This study aimed to provide a perspective for the interpretation of exercise capacity (peakVO2) in patients with repaired Tetralogy of Fallot (patients with rTOF) by describing the course of peakVO2 from patients aged 6-63 years. METHODS: A retrospective study was performed between September 2001 and December 2016 in the German Heart Centre Munich, Germany, and in the University Medical Centre Groningen, the Netherlands. A total of 1175 cardiopulmonary exercise tests (CPETs) were collected from 586 patients with rTOF, 46% female. Maximal exertion was verified using a respiratory exchange ratio ā„1.00. PeakVO2 was modelled using time-dependent multilevel models for repeated measurements (n=889 in 300 patients), and compared with subject-specific reference values calculated by the models of Bongers et al and Mylius et al. RESULTS: The peakVO2 of patients with rTOF was reduced at all ages. At the age of 6, the peakVO2 was 614 mL/min (70% of predicted (95%āCI 67 to 73)). The reduced increase in peakVO2 during adolescence resulted in a significant lower maximum peakVO2 of 1209 mL/min at 25 years (65% predicted, p<0.001). A linear decline after 25 years was observed in patients and references, although patients showed an accelerated decline, with a -0.24% point of predicted (95%āCI 0.11 to 0.38) per year without differences between sexes (p=0.263). CONCLUSIONS: This study provides a context for peakVO2 across ages in patients with rTOF under contemporary treatment strategies. It showed that the reduction in peakVO2 originates from childhood and declines over time. Sex differences in patients with rTOF were similar to natural existing sex differences
Transcriptome changes in newborn goats' skeletal muscle as a result of maternal feed restriction at different stages of gestation
We investigated how feed restriction at 50% of maintenance requirements during different stages of gestation affects the transcriptome of newborn goats' skeletal muscle. Fourteen pregnant dams were randomly assigned into one of the following dietary treatments: animals fed at 50% of maintenance requirement from 8-84 d of gestation and then fed at 100% of maintenance requirement from day 85 of gestation to parturition (RM, n = 6), and animals fed at 100% of maintenance requirement from 8-84 d of gestation and then fed at 50% of maintenance requirement from day 85 of gestation to parturition (MR, n = 8). At birth, samples of offspring's Longissimus muscle were collected for total RNA extraction and sequencing. Our data showed 66 differentially expressed (DE) genes (FDR < 0.05). A total of 6 genes were upregulated and 60 downregulated (FDR < 0.05) in the skeletal muscle of the newborns resulting from treatment RM compared with MR. Our results suggest that the DE genes upregulated in newborn goats' skeletal muscle from the RM group compared to MR, included genes related to satellite cells, and genes that indicates impaired insulin sensitivity and changes in the composition of intramuscular fat. The DE genes upregulated in newborn goats' skeletal muscle from the MR group compared to RM, are also related to impaired insulin sensitivity, as well as a predominantly oxidative metabolism and cellular oxidative stress. However, protective mechanisms against insulin sensitivity and oxidative stress may have been augmented in the skeletal muscle of offspring from MR treatment compared to RM, in order to maintain cellular homeostasis
DMRcaller: a versatile R/Bioconductor package for detection and visualization of differentially methylated regions in CpG and non-CpG contexts
DNA methylation has been associated with transcriptional repression and detection of differential methylation is important in understanding the underlying causes of differential gene expression. Bisulfite-converted genomic DNA sequencing is the current gold standard in the field for building genome-wide maps at a base pair resolution of DNA methylation. Here we systematically investigate the underlying features of detecting differential DNA methylation in CpG and non-CpG contexts, considering both the case of mammalian systems and plants. In particular, we introduce DMRcaller, a highly efficient R/Bioconductor package, which implements several methods to detect Differentially Methylated Regions (DMRs) between two samples. Most importantly, we show that different algorithms are required to compute DMRs and the most appropriate algorithm in each case depends on the sequence context and levels of methylation. Furthermore, we show that DMRcaller outperforms other available packages and we propose a new method to select the parameters for this tool and for other available tools. DMRcaller is a comprehensive tool for differential methylation analysis which displays high sensitivity and specificity for the detection of DMRs and performs entire genome wide analysis within a few hours
Understanding the dynamics of Toll-like Receptor 5 response to flagellin and its regulation by estradiol
Ā© 2017 The Author(s). Toll-like receptors (TLRs) are major players of the innate immune system. Once activated, they trigger a signalling cascade that leads to NF-ĆĀ° B translocation from the cytoplasm to the nucleus. Single cell analysis shows that NF-ĆĀ° B signalling dynamics are a critical determinant of transcriptional regulation. Moreover, the outcome of innate immune response is also affected by the cross-talk between TLRs and estrogen signalling. Here, we characterized the dynamics of TLR5 signalling, responsible for the recognition of flagellated bacteria, and those changes induced by estradiol in its signalling at the single cell level. TLR5 activation in MCF7 cells induced a single and sustained NF-k B translocation into the nucleus that resulted in high NF-k B transcription activity. The overall magnitude of NF-k B transcription activity was not influenced by the duration of the stimulus. No significant changes are observed in the dynamics of NF-k B translocation to the nucleus when MCF7 cells are incubated with estradiol. However, estradiol significantly decreased NF-k B transcriptional activity while increasing TLR5-mediated AP-1 transcription. The effect of estradiol on transcriptional activity was dependent on the estrogen receptor activated. This fine tuning seems to occur mainly in the nucleus at the transcription level rather than affecting the translocation of the NF-k B transcription factor
Thermal responses of single zone offices on existing near-extreme summer weather data
There have been a number of attempts in the past to define ānear extremeā weather for facilitating overheating analysis in free running buildings. The most recently efforts include CIBSE latest release of Design Summer Year (DSY) weather using multiple complete weather years and a newly proposed composite DSY. This research aims to assess how various single zone offices respond to these new definitions of near extreme weathers. Parametric studies were carried out on single zone offices through which four sampling sets of models were employed to examine the thermal responses of dry bulb temperature, global solar radiation & wind speed collectively. London weather data from 1976 to 1995 were used and the overheating assessments were made based on CIBSE Guide A & BS EN 15251. The research discovers that solar radiation and wind both influence the predicted indoor warmth with solar radiation has obvious stronger impacts than wind. No perfect correlation was found from observation and Spearmanās rank order analysis on the ranks between the weather warmth and the predicted indoor warmth. The ranks made using multiple weather parameters show better correlation than some of the dry bulb temperature only metrics. The research also discovers that the Test Reference Year weather behaves warmer than expected. It is also found that a single complete year can not represent the near-extreme consistently and there is no evidence a composite DSY is better statistically. These findings support the notion of using multiple complete warm weather years for overheating assessments
Alkaline Phosphatases: Structure, substrate specificity and functional relatedness to other members of a large superfamily of enzymes
Our knowledge of the structure and function of alkaline phosphatases has increased greatly in recent years. The crystal structure of the human placental isozyme has enabled us to probe salient features of the mammalian enzymes that differ from those of the bacterial enzymes. The availability of knockout mice deficient in each of the murine alkaline phosphatase isozymes has also given deep insights into their in vivo role. This has been particularly true for probing the biological role of bone alkaline phosphatase during skeletal mineralization. Due to space constraints this mini-review focuses exclusively on structural and functional features of mammalian alkaline phosphatases as identified by crystallography and probed by site-directed mutagenesis and kinetic analysis. An emphasis is also placed on the substrate specificity of alkaline phosphatases, their catalytic properties as phosphohydrolases as well as phosphodiesterases and their structural and functional relatedness to a large superfamily of enzymes that includes nucleotide pyrophosphatase/phosphodiesterase
GPX4 regulates cellular necrosis and host resistance in Mycobacterium tuberculosis infection
Cellular necrosis during Mycobacterium tuberculosis (Mtb) infection promotes both immunopathology and bacterial dissemination. Glutathione peroxidase-4 (Gpx4) is an enzyme that plays a critical role in preventing iron-dependent lipid peroxidationāmediated cell death (ferroptosis), a process previously implicated in the necrotic pathology seen in Mtb-infected mice. Here, we document altered GPX4 expression, glutathione levels, and lipid peroxidation in patients with active tuberculosis and assess the role of this pathway in mice genetically deficient in or overexpressing Gpx4. We found that Gpx4-deficient mice infected with Mtb display substantially increased lung necrosis and bacterial burdens, while transgenic mice overexpressing the enzyme show decreased bacterial loads and necrosis. Moreover, Gpx4-deficient macrophages exhibited enhanced necrosis upon Mtb infection in vitro, an outcome suppressed by the lipid peroxidation inhibitor, ferrostatin-1. These findings provide support for the role of ferroptosis in Mtb-induced necrosis and implicate the Gpx4/GSH axis as a target for host-directed therapy of tuberculosis
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