892 research outputs found
Improving the applicability of radar rainfall estimates for urban pluvial flood modelling and forecasting
This work explores the possibility of improving the applicability of radar rainfall estimates (whose accuracy is generally insufficient) to the verification and operation of urban storm-water drainage models by employing a number of local gauge-based radar rainfall adjustment techniques. The adjustment techniques tested in this work include a simple mean-field bias (MFB) adjustment, as well as a more complex Bayesian radar-raingauge data merging method which aims at better preserving the spatial structure of rainfall fields. In addition, a novel technique (namely, local singularity analysis) is introduced and shown to improve the Bayesian method by better capturing and reproducing storm patterns and peaks. Two urban catchments were used as case studies in this work: the Cranbrook catchment (9 km2) in North-East London, and the Portobello catchment (53 km2) in the East of Edinburgh. In the former, the potential benefits of gauge-based adjusted radar rainfall estimates in an operational context were analysed, whereas in the latter the potential benefits of adjusted estimates for model verification purposes were explored. Different rainfall inputs, including raingauge, original radar and the aforementioned merged estimates were fed into the urban drainage models of the two catchments. The hydraulic outputs were compared against available flow and depth records. On the whole, the tested adjustment techniques proved to improve the applicability of radar rainfall estimates to urban hydrological applications, with the Bayesian-based methods, in particular the singularity sensitive one, providing more realistic and accurate rainfall fields which result in better reproduction of the urban drainage systemâs dynamics. Further testing is still necessary in order to better assess the benefits of these adjustment methods, identify their shortcomings and improve them accordingly
Induced CNS expression of CXCL1 augments neurologic disease in a murine model of multiple sclerosis via enhanced neutrophil recruitment.
Increasing evidence points to an important role for neutrophils in participating in the pathogenesis of the human demyelinating disease MS and the animal model EAE. Therefore, a better understanding of the signals controlling migration of neutrophils as well as evaluating the role of these cells in demyelination is important to define cellular components that contribute to disease in MS patients. In this study, we examined the functional role of the chemokine CXCL1 in contributing to neuroinflammation and demyelination in EAE. Using transgenic mice in which expression of CXCL1 is under the control of a tetracycline-inducible promoter active within glial fibrillary acidic protein-positive cells, we have shown that sustained CXCL1 expression within the CNS increased the severity of clinical and histologic disease that was independent of an increase in the frequency of encephalitogenic Th1 and Th17 cells. Rather, disease was associated with enhanced recruitment of CD11b+ Ly6G+ neutrophils into the spinal cord. Targeting neutrophils resulted in a reduction in demyelination arguing for a role for these cells in myelin damage. Collectively, these findings emphasize that CXCL1-mediated attraction of neutrophils into the CNS augments demyelination suggesting that this signaling pathway may offer new targets for therapeutic intervention
Biophysical and Economic Evaluation of Hedgerow Intercropping Using SCUAF in Lampung, Indonesia
IndonesianStudi ini mengungkap dampak jangka panjang (20 tahun) tiga sistem USAha tani dengan menggunakan pendekatan model bioekonomik, yang disebut Model Soil Change Under Agro Forestry (SCUAF). Teknik konservasi introduksi USAha tani tanaman lorong Flemingia dibandingkan dengan dua jenis sistem USAha tani tradisional yaitu perladangan berpindah dengan masa bera tiga tahun dan sistem USAha tani tanaman pangan sepanjang tahun. Tingkat erosi dan kesuburan lahan menurun secara drastis pada sistem USAha tani tradisional, khususnya pada sistem USAha tani tanaman pangan sepanjang tahun. Dalam 20 tahun, sistem USAha tani tradisional ini kehilangan volume lahan hampir 20 kali, dan unsur hara (soil nutrient) mendekati tiga kali lebih besar dibandingkan dengan teknologi konservasi tanaman lorong. Produktivitas tanaman menurun pada ketiga sistem USAha tani, tetapi penurunan cukup tajam (81%) terdapat pada sistem USAha tani tanaman pangan sepanjang tahun dan hanya 30 persen pada sistem USAha tani tanaman lorong. Sistem perladangan berpindah memiliki Net Precent Value (NPV) paling rendah. Dalam jangka panjang, teknologi konservasi tanaman lorong mampu memberikan keuntungan finansial yang tertinggi dan dapat menjamin keberlanjutan USAha tani. Namun demikian, teknologi introduksi ini membutuhkan dukungan modal yang relatif besar pada tahap awal, sehingga dalam implementasinya perlu didukung dengan kebijaksanaan perkreditan di samping kepastian status penguasaan lahan.EnglishThis study reveals long term (20 years) impact of three farming systems using an approach of bio-economic model called Soil Change Under Agro Forestry (SCUAF). An introduced conservation technique of Flemingia inter-cropping system was compared to two traditional farming systems i.e. shifting cultivation with three years fallow and a long year food crop farming system. Soil erosion rate and land fertility decreased drastically on land used for traditional farming system especially for that of the long year food crop farming system. In 20 years, the traditional farming system lost soil volume almost 20 times and soil nutrient for almost three times compared to that of hedgerow inter-cropping farming system technique. Plant productivity for all techniques decreased, however, the long year food crop farming system experienced the most (81 %) compared to hedgerow inter-cropping using SCUAF (30% ). Net Present Value (NPV) for shifting cultivation was the lowest. In a long term, the hedgerow inter-cropping using SCUAF gives the highest financial profit and assures farming sustainability. However, this introduced technology requires relatively high capital support at the initiation phase so that it needs PRIVATE credit policy support besides land holding status certainty
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Disrupted CXCR2 Signaling in Oligodendroglia Lineage Cells Enhances Myelin Repair in a Viral Model of Multiple Sclerosis.
CXCR2 is a chemokine receptor expressed on oligodendroglia that has been implicated in the pathogenesis of neuroinflammatory demyelinating diseases as well as enhancement of the migration, proliferation, and myelin production by oligodendroglia. Using an inducible proteolipid protein (Plp) promoter-driven Cre-loxP recombination system, we were able to assess how timed ablation of Cxcr2 in oligodendroglia affected disease following intracranial infection with the neurotropic JHM strain of mouse hepatitis virus (JHMV). Generation of Plp-Cre-ER(T)::Cxcr2flox/flox transgenic mice (termed Cxcr2-CKO mice) allows for Cxcr2 to be silenced in oligodendrocytes in adult mice following treatment with tamoxifen. Ablation of oligodendroglia Cxcr2 did not influence clinical severity in response to intracranial infection with JHMV. Infiltration of activated T cells or myeloid cells into the central nervous system (CNS) was not affected, nor was the ability to control viral infection. In addition, the severity of demyelination was similar between tamoxifen-treated mice and vehicle-treated controls. Notably, deletion of Cxcr2 resulted in increased remyelination, as assessed by g-ratio (the ratio of the inner axonal diameter to the total outer fiber diameter) calculation, compared to that in vehicle-treated control mice. Collectively, our findings argue that CXCR2 signaling in oligodendroglia is dispensable with regard to contributing to neuroinflammation, but its deletion enhances remyelination in a preclinical model of the human demyelinating disease multiple sclerosis (MS).IMPORTANCE Signaling through the chemokine receptor CXCR2 in oligodendroglia is important for developmental myelination in rodents, while chemical inhibition or nonspecific genetic deletion of CXCR2 appears to augment myelin repair in animal models of the human demyelinating disease multiple sclerosis (MS). To better understand the biology of CXCR2 signaling on oligodendroglia, we generated transgenic mice in which Cxcr2 is selectively ablated in oligodendroglia upon treatment with tamoxifen. Using a viral model of neuroinflammation and demyelination, we demonstrate that genetic silencing of CXCR2 on oligodendroglia did not affect clinical disease, neuroinflammation, or demyelination, yet there was increased remyelination. These findings support and extend previous findings suggesting that targeting CXCR2 may offer a therapeutic avenue for enhancing remyelination in patients with demyelinating diseases
Pre-Existing Mature Oligodendrocytes Do Not Contribute to Remyelination following Toxin-Induced Spinal Cord Demyelination.
Remyelination is the regenerative response to demyelination. Although the oligodendrocyte progenitor is established as the major source of remyelinating cells, there is no conclusive evidence on whether mature, differentiated oligodendrocytes can also contribute to remyelination. Using two different inducible myelin-CreER mouse strains in which mature oligodendrocytes were prelabeled by the expression of membrane-bound Green fluorescent protein, we found that after focal spinal cord demyelination, the surrounding surviving labeled oligodendrocytes did not proliferate but remained at a consistent density. Furthermore, existing (prelabeled) oligodendrocytes showed no evidence of incorporation or migration into the lesioned area, or of process extension from the peripheral margins into the lesion. Thus, mature oligodendrocytes do not normally contribute to remyelination and are therefore not a promising target for regenerative therapy.Supported by European Research Council grant agreement 293544 (W.D.R.), Wellcome Trust grant WT100269AIA, Medical Research Council grant G0800575, a Royal Society-USA/Canada Exchange Fellowship (I.M.), the UK Multiple Sclerosis Society, and a Wellcome Trust Integrated Veterinary Training Fellowship (A.H.C.)
Lactate saturation limits bicarbonate detection in hyperpolarized 13 C-pyruvate MRI of the brain
PURPOSE: To investigate the potential effects of [1â(13)C]lactate RF saturation pulses on [(13)C]bicarbonate detection in hyperpolarized [1â(13)C]pyruvate MRI of the brain. METHODS: Thirteen healthy rats underwent MRI with hyperpolarized [1â(13)C]pyruvate of either the brain (n =â8) or the kidneys, heart, and liver (n =â5). Dynamic, metaboliteâselective imaging was used in a crossâover experiment in which [1â(13)C]lactate was excited with either 0° or 90° flip angles. The [(13)C]bicarbonate SNR and apparent [1â(13)C]pyruvateâtoâ[(13)C]bicarbonate conversion (k (PB)) were determined. Furthermore, simulations were performed to identify the SNR optimal flipâangle scheme for detection of [1â(13)C]lactate and [(13)C]bicarbonate. RESULTS: In the brain, the [(13)C]bicarbonate SNR was 64% higher when [1â(13)C]lactate was not excited (5.8â±â1.5 vs 3.6â±â1.3; 1.2 to 3.3âpoint increase; pâ=â0.0027). The apparent k (PB) decreased 25% with [1â(13)C]lactate saturation (0.0047â±â0.0008âs(â1) vs 0.0034â±â0.0006âs(â1); 95% confidence interval, 0.0006â0.0019âs(â1) increase; p =â0.0049). These effects were not present in the kidneys, heart, or liver. Simulations suggest that the optimal [(13)C]bicarbonate SNR with a TR of 1âs in the brain is obtained with [(13)C]bicarbonate, [1â(13)C]lactate, and [1â(13)C]pyruvate flip angles of 60°, 15°, and 10°, respectively. CONCLUSIONS: Radiofrequency saturation pulses on [1â(13)C]lactate limit [(13)C]bicarbonate detection in the brain specifically, which could be due to shuttling of lactate from astrocytes to neurons. Our results have important implications for experimental design in studies in which [(13)C]bicarbonate detection is warranted
Estimating cetacean population trends from static acoustic monitoring data using Paired Year Ratio Assessment (PYRA)
This is the final version. Available on open access from Public Library of Science via the DOI in this recordData Availability: All relevant data are within the manuscript and its Supporting information files.The cetacean conservationist is often faced with evaluating population trends from abundance data that are either sparse or recorded at different times in different years. The presence of diel or seasonal patterns in the data together with unplanned gaps is often problematic. Such data are typical of those obtained from static acoustic monitoring. We present a simple and transparent non-parametric trend evaluation method, âPaired Year Ratio Assessment (PYRA)â that uses only whole days of data wherever they are present in each of successive pairs of periods of 365 days. We provide a quantitative comparison of the performance of PYRA with traditional generalised additive models (GAMS) and nonparametric randomisation tests that require a greater level of skill and experience for both application and interpretation. We conclude that PYRA is a powerful tool, particularly in the context of identifying population trends which is often the main aim of conservation-targeted acoustic monitoring.Innovate UKChelonia UK Ltd.Research Englan
Life-history traits of the giant squid Architeuthis dux revealed from stable isotope signatures recorded in beaks
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