509 research outputs found
Evaluating the impacts of flooding on the residents of Lagos, Nigeria
The occurrence of natural disasters is of growing concern globally due to increasing disruption, damage and loss of life. The rising flood frequency in Lagos, Nigeria, emphasises the need for improved flood prevention and management measures. This study evaluates the impacts of flooding on the residents of Lagos, Nigeria by focusing on five areas: Lekki, Victoria Island, Ikeja, Surulere and Ikorodu. Each area represents a different income level and population density. Flood managers in Lagos were also interviewed to understand the flood management and prevention situation from the governmentâs perspective, together with the barriers and drivers to effective flood management. Data collected from residents indicate that heavy rainfall, blocked and/or failure of drainage systems, and lack of land use planning were considered the most frequent contributors to the flooding problem. A high proportion of residents live in flood prone areas, having been unaware of the initial flood problem, or selecting the area due to proximity to work or affordability. Government initiated flood awareness campaigns aimed to inform residents. However, some residents continue to live in homes at risk from flooding due to sentimental values, whilst others simply cannot afford to move houses. Results revealed some of the impacts of flooding include displacement, damage to property, and disruption to movement and health issues. The study recommends that residents need to be more aware of proper waste disposal. The government also needs to implement controls on development on flood plain, ensure better and regular waste collection methods, proper maintenance of drainage systems and better flood defences are in place. Also, offering incentives should be in place for residents willing to move to minimise impacts of flooding
Dominant Nuclear Outflow Driving Mechanisms in Powerful Radio Galaxies
In order to identify the dominant nuclear outflow mechanisms in Active
Galactic Nuclei, we have undertaken deep, high resolution observations of two
compact radio sources (PKS 1549-79 and PKS 1345+12) with the Advanced Camera
for Surveys (ACS) aboard the Hubble Space Telescope. Not only are these targets
known to have powerful emission line outflows, but they also contain all the
potential drivers for the outflows: relativistic jets, quasar nuclei and
starbursts. ACS allows the compact nature (<0.15") of these radio sources to be
optically resolved for the first time. Through comparison with existing radio
maps we have seen consistency in the nuclear position angles of both the
optical emission line and radio data. There is no evidence for bi-conical
emission line features on the large-scale and there is a divergance in the
relative position angles of the optical and radio structure. This enables us to
exclude starburst driven outflows. However, we are unable to clearly
distinguish between radiative AGN wind driven outflows and outflows powered by
relativistic radio jets. The small scale bi-conical features, indicative of
such mechanisms could be below the resolution limit of ACS, especially if
aligned close to the line of sight. In addition, there may be offsets between
the radio and optical nuclei induced by heavy dust obscuration, nebular
continuum or scattered light from the AGN.Comment: 9 pages, 8 figures, emulateapj, ApJ Accepte
Structure-guided optimisation of N-hydroxythiazole-derived inhibitors of factor inhibiting hypoxia-inducible factor-α
The human 2-oxoglutarate (2OG)- and Fe(II)-dependent oxygenases factor inhibiting hypoxia-inducible factor-α (FIH) and HIF-α prolyl residue hydroxylases 1â3 (PHD1â3) regulate the response to hypoxia in humans via catalysing hydroxylation of the α-subunits of the hypoxia-inducible factors (HIFs). Small-molecule PHD inhibitors are used for anaemia treatment; by contrast, few selective inhibitors of FIH have been reported, despite their potential to regulate the hypoxic response, either alone or in combination with PHD inhibition. We report molecular, biophysical, and cellular evidence that the N-hydroxythiazole scaffold, reported to inhibit PHD2, is a useful broad spectrum 2OG oxygenase inhibitor scaffold, the inhibition potential of which can be tuned to achieve selective FIH inhibition. Structure-guided optimisation resulted in the discovery of N-hydroxythiazole derivatives that manifest substantially improved selectivity for FIH inhibition over PHD2 and other 2OG oxygenases, including Jumonji-C domain-containing protein 5 (âŒ25-fold), aspartate/asparagine-ÎČ-hydroxylase (>100-fold) and histone NΔ-lysine demethylase 4A (>300-fold). The optimised N-hydroxythiazole-based FIH inhibitors modulate the expression of FIH-dependent HIF target genes and, consistent with reports that FIH regulates cellular metabolism, suppressed lipid accumulation in adipocytes. Crystallographic studies reveal that the N-hydroxythiazole derivatives compete with both 2OG and the substrate for binding to the FIH active site. Derivatisation of the N-hydroxythiazole scaffold has the potential to afford selective inhibitors for 2OG oxygenases other than FIH
A Comparison of Eight Optimization Methods Applied to a Wind Farm Layout Optimization Problem
Selecting a wind farm layout optimization method is difficult. Comparisons between optimization methods in different papers can be uncertain due to the difficulty of exactly reproducing the objective function. Comparisons by just a few authors in one paper can be uncertain if the authors do not have experience using each algorithm. In this work we provide an algorithm comparison for a wind farm layout optimization case study between eight optimization methods applied, or directed, by researchers who developed those algorithms or who had other experience using them. We provided the objective function to each researcher to avoid ambiguity about relative performance due to a difference in objective function. While these comparisons are not perfect, we try to treat each algorithm more fairly by having researchers with experience using each algorithm apply each algorithm and by having a common objective function provided for analysis. The case study is from the IEA Wind Task 37, based on the Borssele III and IV wind farms with 81 turbines. Of particular interest in this case study is the presence of disconnected boundary regions and concave boundary features. The optimization methods studied represent a wide range of approaches, including gradient-free, gradient-based, and hybrid methods; discrete and continuous problem formulations; single-run and multi-start approaches; and mathematical and heuristic algorithms. We provide descriptions and references (where applicable) for each optimization method as well as lists of pros and cons to help readers determine an appropriate method for their use case. All the optimization methods perform similarly, with optimized wake loss values between 15.48 % and 15.70 % as compared to 17.28 % for the unoptimized provided layout. Each of the layouts found were different, but all layouts exhibited similar characteristics. Strong similarities across all the layouts include tightly packing wind turbines along the outer borders, loosely spacing turbines in the internal regions, and allocating similar numbers of turbines to each discrete boundary region. The best layout by AEP was found using a new sequential allocation method, discreet exploration-based optimization (DEBO). Based on the results in this study, it appears that using an optimization algorithm can significantly improve wind farm performance, but there are many optimization methods that can perform well on the wind farm layout optimization problem given that they are applied correctly.</p
Co-circulation of Multidrug-resistant Shigella Among Men Who Have Sex With Men in Australia.
BACKGROUND: In urban Australia, the burden of shigellosis is either in returning travelers from shigellosis-endemic regions or in men who have sex with men (MSM). Here, we combine genomic data with comprehensive epidemiological data on sexual exposure and travel to describe the spread of multidrug-resistant Shigella lineages. METHODS: A population-level study of all cultured Shigella isolates in the state of Victoria, Australia, was undertaken from 1 January 2016 through 31 March 2018. Antimicrobial susceptibility testing, whole-genome sequencing, and bioinformatic analyses of 545 Shigella isolates were performed at the Microbiological Diagnostic Unit Public Health Laboratory. Risk factor data on travel and sexual exposure were collected through enhanced surveillance forms or by interviews. RESULTS: Rates of antimicrobial resistance were high, with 17.6% (95/541) and 50.6% (274/541) resistance to ciprofloxacin and azithromycin, respectively. There were strong associations between antimicrobial resistance, phylogeny, and epidemiology. Specifically, 2 major MSM-associated lineages were identified: a Shigellasonnei lineage (n = 159) and a Shigella flexneri 2a lineage (n = 105). Of concern, 147/159 (92.4%) of isolates within the S. sonnei MSM-associated lineage harbored mutations associated with reduced susceptibility to recommended oral antimicrobials: namely, azithromycin, trimethoprim-sulfamethoxazole, and ciprofloxacin. Long-read sequencing demonstrated global dissemination of multidrug-resistant plasmids across Shigella species and lineages, but predominantly associated with MSM isolates. CONCLUSIONS: Our contemporary data highlight the ongoing public health threat posed by resistant Shigella, both in Australia and globally. Urgent multidisciplinary public health measures are required to interrupt transmission and prevent infection
Adolescent Intermittent Ethanol Increases the Sensitivity to the Reinforcing Properties of Ethanol and the Expression of Select Cholinergic and Dopaminergic Genes within the Posterior Ventral Tegmental Area
Background
Although not legally allowed to consume alcohol, adolescents account for 11% of all alcohol use in the United States and approximately 90% of adolescent intake is in the form of an alcohol binge. The adolescent intermittent ethanol (AIE) model developed by the NADIA consortium produces bingeâlike EtOH exposure episodes. The current experiment examined the effects of AIE on the reinforcing properties of EtOH and genetic expression of cholinergic and dopaminergic factors within the posterior ventral tegmental area (pVTA) in Wistar male and female rats and in male alcoholâpreferring (P) rats.
Methods
Rats were exposed to the AIE or water during adolescence, and all testing occurred during adulthood. Wistar control and AIE rats were randomly assigned to groups that selfâadministered 0 to 200 mg% EtOH. Male P rats selfâadministered 0 to 100 mg%.
Results
The data indicated that exposure to AIE in both Wistar male and female rats (and male P rats) resulted in a significant leftward shift in doseâresponse curve for EtOH selfâadministration into the pVTA. TaqMan array indicated that AIE exposure had divergent effects on the expression of nicotinic receptors (increased a7, reduction in a4 and a5). There were also sexâspecific effects of AIE on gene expression; male only reduction in D3 receptors.
Conclusion
Bingeâlike EtOH exposure during adolescence enhances the sensitivity to the reinforcing properties of EtOH during adulthood which could be part of biological sequelae that are the basis for the deleterious effects of adolescent alcohol consumption on the rate of alcoholism during adulthood
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Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora
Background
The best documented survival responses of organisms to past climate change on short (glacial-interglacial) timescales are distributional shifts. Despite ample evidence on such timescales for local adaptations of populations at specific sites, the long-term impacts of such changes on evolutionary significant units in response to past climatic change have been little documented. Here we use phylogenies to reconstruct changes in distribution and flowering ecology of the Cape flora - South Africa's biodiversity hotspot - through a period of past (Neogene and Quaternary) changes in the seasonality of rainfall over a timescale of several million years.
Results
Forty-three distributional and phenological shifts consistent with past climatic change occur across the flora, and a comparable number of clades underwent adaptive changes in their flowering phenology (9 clades; half of the clades investigated) as underwent distributional shifts (12 clades; two thirds of the clades investigated). Of extant Cape angiosperm species, 14-41% have been contributed by lineages that show distributional shifts consistent with past climate change, yet a similar proportion (14-55%) arose from lineages that shifted flowering phenology.
Conclusions
Adaptive changes in ecology at the scale we uncover in the Cape and consistent with past climatic change have not been documented for other floras. Shifts in climate tolerance appear to have been more important in this flora than is currently appreciated, and lineages that underwent such shifts went on to contribute a high proportion of the flora's extant species diversity. That shifts in phenology, on an evolutionary timescale and on such a scale, have not yet been detected for other floras is likely a result of the method used; shifts in flowering phenology cannot be detected in the fossil record
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Individual common variants exert weak effects on the risk for autism spectrum disorders.
While it is apparent that rare variation can play an important role in the genetic architecture of autism spectrum disorders (ASDs), the contribution of common variation to the risk of developing ASD is less clear. To produce a more comprehensive picture, we report Stage 2 of the Autism Genome Project genome-wide association study, adding 1301 ASD families and bringing the total to 2705 families analysed (Stages 1 and 2). In addition to evaluating the association of individual single nucleotide polymorphisms (SNPs), we also sought evidence that common variants, en masse, might affect the risk. Despite genotyping over a million SNPs covering the genome, no single SNP shows significant association with ASD or selected phenotypes at a genome-wide level. The SNP that achieves the smallest P-value from secondary analyses is rs1718101. It falls in CNTNAP2, a gene previously implicated in susceptibility for ASD. This SNP also shows modest association with age of word/phrase acquisition in ASD subjects, of interest because features of language development are also associated with other variation in CNTNAP2. In contrast, allele scores derived from the transmission of common alleles to Stage 1 cases significantly predict case status in the independent Stage 2 sample. Despite being significant, the variance explained by these allele scores was small (Vm< 1%). Based on results from individual SNPs and their en masse effect on risk, as inferred from the allele score results, it is reasonable to conclude that common variants affect the risk for ASD but their individual effects are modest
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