877 research outputs found
Modified BEAM Rubber Agroforestry Models: RRYIELD and RRECON
Resource /Energy Economics and Policy,
Reproductive performance of resident and migrant males, females and pairs in a partially migratory bird
We thank everyone from the Centre for Ecology & Hydrology (CEH) who contributed to data collection, and Scottish Natural Heritage for access to the Isle of May National Nature Reserve. We thank the Scottish Ornithologists’ Club (SOC) for their support, and all volunteer observers, particularly Raymond Duncan, Moray Souter and Bob Swann. HG was funded by a Natural Environment Research Council (NERC) CASE studentship supported by CEH and SOC, FD, SW, MPH, MN and SB were funded by NERC and the Joint Nature Conservation Committee, and JMR was part-funded by the Royal Society. Finally, we thank the Associate Editor and two reviewers for constructive comments on the manuscript. The data are available from the Dryad Digital Repository https://doi.org/10.5061/dryad.532j0 (Grist et al., 2017)Peer reviewedPublisher PD
Kv2 dysfunction after peripheral axotomy enhances sensory neuron responsiveness to sustained input
AbstractPeripheral nerve injuries caused by trauma are associated with increased sensory neuron excitability and debilitating chronic pain symptoms. Axotomy-induced alterations in the function of ion channels are thought to largely underlie the pathophysiology of these phenotypes. Here, we characterise the mRNA distribution of Kv2 family members in rat dorsal root ganglia (DRG) and describe a link between Kv2 function and modulation of sensory neuron excitability. Kv2.1 and Kv2.2 were amply expressed in cells of all sizes, being particularly abundant in medium-large neurons also immunoreactive for neurofilament-200. Peripheral axotomy led to a rapid, robust and long-lasting transcriptional Kv2 downregulation in the DRG, correlated with the onset of mechanical and thermal hypersensitivity. The consequences of Kv2 loss-of-function were subsequently investigated in myelinated neurons using intracellular recordings on ex vivo DRG preparations. In naïve neurons, pharmacological Kv2.1/Kv2.2 inhibition by stromatoxin-1 (ScTx) resulted in shortening of action potential (AP) after-hyperpolarization (AHP). In contrast, ScTx application on axotomized neurons did not alter AHP duration, consistent with the injury-induced Kv2 downregulation. In accordance with a shortened AHP, ScTx treatment also reduced the refractory period and improved AP conduction to the cell soma during high frequency stimulation. These results suggest that Kv2 downregulation following traumatic nerve lesion facilitates greater fidelity of repetitive firing during prolonged input and thus normal Kv2 function is postulated to limit neuronal excitability. In summary, we have profiled Kv2 expression in sensory neurons and provide evidence for the contribution of Kv2 dysfunction in the generation of hyperexcitable phenotypes encountered in chronic pain states
Suspected Laminosioptes cysticola (fowl cyst mite) lesions in backyard chickens in southern England
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
Seasonal variability of the warm Atlantic Water layer in the vicinity of the Greenland shelf break
The warmest water reaching the east and west coast of Greenland is found between 200?m and 600?m. Whilst important for melting Greenland's outlet glaciers, limited winter observations of this layer prohibit determination of its seasonality. To address this, temperature data from Argo profiling floats, a range of sources within the World Ocean Database and unprecedented coverage from marine-mammal borne sensors have been analysed for the period 2002-2011. A significant seasonal range in temperature (~1-2?°C) is found in the warm layer, in contrast to most of the surrounding ocean. The phase of the seasonal cycle exhibits considerable spatial variability, with the warmest water found near the eastern and southwestern shelf-break towards the end of the calendar year. High-resolution ocean model trajectory analysis suggest the timing of the arrival of the year's warmest water is a function of advection time from the subduction site in the Irminger Basin
Tracing oceanic sources of heat content available for Atlantic hurricanes
In the Main Development Region (MDR) for Atlantic hurricanes, the volume of water warmer than 26.5°C quantifies the potential source of energy for major storms. Taking a Lagrangian perspective, this warm water is backtracked on seasonal timescales in an eddy-resolving ocean model hindcast spanning 1988–2010. Being confined near the surface and assuming a mixed layer depth of 50 m, net heat fluxes into or out of water parcels advected toward the MDR are inferred from along-trajectory temperature tendencies. To first order, these heat fluxes match surface net heat fluxes during the months over which water advects into the region. Contributions to this warm water in the preceding 6 months include water resident in the MDR (20%–40%), arriving via the North Brazil Current (NBC, 5%–15%), or via Ekman drift across 10°S. In relative terms, decreased contributions from the NBC and Ekman drift and more in situ warming within the MDR lead to warmer, more active hurricane seasons
Observed and projected changes in North Atlantic seasonal temperature reduction and their drivers
The autumn-winter seasonal temperature reduction (STR) of the surface North Atlantic Ocean is investigated with control and climate change simulations of a coupled model and an observation-based sea surface temperature (SST) data set. In the climate change simulation, an increase in the magnitude of the STR is found over much of the North Atlantic, and this change is particularly marked in sea-ice affected regions and the subpolar gyre. Similar results for the mid-high latitude North Atlantic are obtained in the observational analysis. In particular, both the observation and climate model based results show that the STR has increased in magnitude by up to 0.3°C per decade in the subpolar gyre over the period 1951–2020. Drivers for the stronger STR are explored with a focus on potential contributions from increases in either ocean heat loss or the sensitivity of SST to heat loss. Over a large part of the mid-high latitude North Atlantic surface heat loss is found to have weakened in recent decades and is therefore not responsible for the stronger STR (exceptions to this are the near-coastal areas where sea-ice loss is important). In contrast, analysis of daily sensible and latent heat flux data reveals that the sensitivity of SST to heat loss has increased indicating that this term has played a major role in the stronger STR. Areas of greater SST sensitivity (and greater STR) are associated with increased surface stratification brought about predominantly by warming of the northern ocean regions
The water mass transformation framework and variability in hurricane activity
Hurricane activity has been higher since 1995 than in the 1970s and 1980s. This rise in activity has been linked to a warming Atlantic. In this study, we consider variability of the volume of water warmer than 26.5 ºC, considered widely to be the temperature threshold crucial to hurricane development. We find the depth of the 26.5 ºC isotherm better correlated with seasonal hurricane counts than SST in the early part of the Atlantic hurricane season in some regions. The volume of water transformed by surface heat fluxes to temperatures above 26.5 ºC is directly calculated using the Water Mass Transformation framework. This volume is compared with the year-to-year changes in the volume of water of this temperature to see how much of the volume can be explained using this calculation. In some years, there is notable correspondence between transformed and observed volume anomalies, but anomalies in other years must be largely associated with other processes, such as the divergence of horizontal heat transport associated with the AMOC. This technique provides evidence that, in a given year, coordinated physical mechanisms are responsible for the build-up of anomalous ocean heat; not only net surface heat exchange but also the convergence of horizontal heat transport from ocean currents, to provide fuel for larger numbers of intense hurricanes
Neuronal RARβ signaling modulates PTEN activity directly in neurons and via exosome transfer in astrocytes to prevent glial scar formation and induce spinal cord regeneration
Failure of axonal regeneration in the central nervous system (CNS) is mainly attributed to a lack of intrinsic neuronal growth programs and an inhibitory environment from a glial scar. Phosphatase and tensin homolog (PTEN) is a major negative regulator of neuronal regeneration and, as such, inhibiting its activity has been considered a therapeutic target for spinal cord (SC) injuries (SCIs). Using a novel model of rat cervical avulsion, we show that treatment with a retinoic acid receptor β (RARβ) agonist results in locomotor and sensory recovery. Axonal regeneration from the severed roots into the SC could be seen by biotinylated dextran amine labeling. Light micrographs of the dorsal root entry zone show the peripheral nervous system (PNS)–CNS transition of regrown axons. RARβ agonist treatment also resulted in the absence of scar formation. Mechanism studies revealed that, in RARβ-agonist-treated neurons, PTEN activity is decreased by cytoplasmic phosphorylation and increased secretion in exosomes. These are taken up by astrocytes, resulting in hampered proliferation and causing them to arrange in a normal-appearing scaffold around the regenerating axons. Attribution of the glial modulation to neuronal PTEN in exosomes was demonstrated by the use of an exosome inhibitor in vivo and PTEN siRNA in vitro assays. The dual effect of RARβ signaling, both neuronal and neuronal–glial, results in axonal regeneration into the SC after dorsal root neurotmesis. Targeting this pathway may open new avenues for the treatment of SCIs. SIGNIFICANCE STATEMENT Spinal cord injuries (SCIs) often result in permanent damage in the adult due to the very limited capacity of axonal regeneration. Intrinsic neuronal programs and the formation of a glial scar are the main obstacles. Here, we identify a single target, neuronal retinoic acid receptor β (RARβ), which modulates these two aspects of the postinjury physiological response. Activation of RARβ in the neuron inactivates phosphatase and tensin homolog and induces its transfer into the astrocytes in small vesicles, where it prevents scar formation. This may open new therapeutic avenues for SCIs
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