258 research outputs found
Gibberellic acid and dwarfism effects on growth and apoplastic peroxidase activity in maize (Zea mays L.) leaf blades.
Dengue transmission risk in a changing climate: Bangladesh is likely to experience a longer dengue fever season in the future
Our changing climate is already affecting the transmission of dengue fever, the fastest growing vector-borne viral disease in the world. This issue presents a significant public health concern for some nations, such as Bangladesh, which already experience regular seasonal outbreaks of dengue fever under present day conditions. To provide guidance for proactive public health planning to potentially mitigate the severity of future outbreaks, we explored the impact of climate change on dengue infections by calculating the change in vectorial capacity (VC) of Aedes aegypti mosquitoes at a seasonal level for all regions in Bangladesh under two scenarios for future atmospheric greenhouse gas concentrations. For each of the four climate models used, and for both scenarios, our analysis revealed that the annual VC remains at a level that would enable potential dengue epidemic transmission in all regions in Bangladesh. We found a slight decline in VC in half of the regions examined during the last two decades of the 21st century for the lower-concentration scenario, with a pronounced decline in VC in all geographic regions beginning in 2060 for the higher-concentration scenario. The likely reason is that in many regions, warming will lead to sub-optimal mosquito breeding temperatures. However, seasonal differences in VC will dissipate as the climate warms, to the point that there is almost no observable seasonality for the higher-concentration scenario during the last two decades of this century. This finding suggests the dengue transmission season could eventually extend to all-year-round transmission, with outbreaks occurring at any time. Consequently, disease surveillance and control activities would need to be geographically and temporally adapted to mitigate dengue epidemic risk in response to climate change
“In Defense of Historical Fiction”: An Unpublished Essay by Edith Simon (Edited, with Introduction and Commentary. by Henry Innes MacAdam)
He [a New Testament Scholar] characterizes the [four canonical] Gospels as “history-like witnesses to truths both historical and transcendent,” which is helpful so long as we do not take “history-like” to mean fictional, in the way that historical novels are “history-like.” [He] maintains that they [the Gospels] are not the kind of narrative about past events that modern historians write
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The specialist insects that rely on the wet-dry habitats of temporary streams
Experimental implementation of a four-level N-type scheme for the observation of Electromagnetically Induced Transparency
A nondegenerate four-level N-type scheme was experimentally implemented to
observe electromagnetically induced transparency (EIT) at the Rb D
line. Radiations of two independent external-cavity semiconductor lasers were
used in the experiment, the current of one of them being modulated at a
frequency equal to the hyperfine-splitting frequency of the excited 5P
level. In this case, apart from the main EIT dip corresponding to the
two-photon Raman resonance in a three-level -scheme, additional dips
detuned from the main dip by a frequency equal to the frequency of the HF
generator were observed in the absorption spectrum. These dips were due to an
increase in the medium transparency at frequencies corresponding to the
three-photon Raman resonances in four-level N-type schemes. The resonance
shapes are analyzed as functions of generator frequency and magnetic field.Comment: 3 pages, 2 figure
Death from early colorectal cancer is predicted by the presence of transcripts of the REG gene family
An intrinsic component of colorectal carcinogenesis may be the capacity to activate regenerative responses simultaneously with inhibition of apoptosis. Since apoptosis is known to be inhibited in colorectal cancer, this study sought evidence for the activation of the REG family of genes which are considered to be activated during regeneration of intestinal mucosa. Transcripts for the REG gene were found in 53% of colorectal cancers and for the PAP gene in 60% of colorectal cancers, by RT-PCR. Using in situ hybridization, the REG transcripts were found to be present in the tumour cells themselves rather than inflammatory or stromal cells. There were no significant correlations between the expression of these two genes and tumour stage, age or sex of the patient population or tumour site. However, in patients with non-metastatic disease who underwent ostensibly curative surgery, the expression of REG alone and co-expression of REG with PAP had a highly significantly adverse effect on survival. These data provide support for the concept that, in some tumours, carcinogenesis involves a regenerative process which co-exists with apoptotic inhibition and may provide a valuable selective indicator of the need for adjuvant therapy in those patients with early-stage colorectal cancer whose disease is destined to recur after curative surgery. © 2000 Cancer Research Campaig
Two-species magneto-optical trap with 40K and 87Rb
We trap and cool a gas composed of 40K and 87Rb, using a two-species
magneto-optical trap (MOT). This trap represents the first step towards cooling
the Bose-Fermi mixture to quantum degeneracy. Laser light for the MOT is
derived from laser diodes and amplified with a single high power semiconductor
amplifier chip. The four-color laser system is described, and the
single-species and two-species MOTs are characterized. Atom numbers of 1x10^7
40K and 2x10^9 87Rb are trapped in the two-species MOT. Observation of trap
loss due to collisions between species is presented and future prospects for
the experiment are discussed.Comment: 4 pages, 4 figures; accepted for publication in Physical Review
Climate change impacts on phenology and yields of five broadacre crops at four climatologically distinct locations in Australia
Shifts in rainfall and rising temperatures due to climate change pose a formidable challenge to the sustainability of broadacre crop yields in Western and South-Eastern Australia. Output from18 Global Climate Models (GCMs) for the Special Report on Emission Scenarios (SRES) A2 scenario was statistically downscaled to four contrasting locations. For the first time in these regions, bias corrected statistically downscaled climate data were employed to drive the Agricultural Production Systems Simulator (APSIM) crop model that integrates the effects of soil, crop phenotype, and management options for a quantitative comparison of crop yields and phenology under an historical and a plausible projected climate. The dynamic APSIM simulation model explore the implications of climate change across multiple locations and multiple time periods (1961–2010, 2030, 2060 and 2090) for multiple key crops (wheat, barley, lupin, canola, field pea) grown in three different types of soil. On average, the ensemble of downscaled GCM projections show a decrease in rainfall in the future at the four locations considered, with increased variability at two locations. At all locations and for five crops, future changes in both crop biomass and grain yield are strongly associated with changes in rainfall (P = 0.05 to P = 0.001). The overall rainfall amount is critical in determining yields but, equally, higher future temperatures can contribute to reducing crop productivity primarily due to advanced crop phenology. For example, for wheat cropping at Hamilton (a higher rainfall site), there is a significant advancement in median flowering date for 2030, 2060, and 2090 of 10, 18, and 29 days respectively with a significant 0.50% grain yield changes for each percentage change in rainfall compared to significant 0.90% grain yield changes in Cunderdin (a lower rainfall site). At all sites except Hamilton, the change in crop grain yield is significantly correlated (P = 0.001) with the percentage change in the future rainfall and the impact increased progressively from higher rainfall to lower rainfall sites. However, the magnitude of the change in crop phenology and yield were not significantly different between soil types. These results help to define regions of concern and their relative importance in the coming years. In this future climate the negative consequences for crop yields and advancement of phenology relative to baseline are not uniform across crops and locations. Of the crops studied – wheat, barley, lupin, canola and field pea – field pea is the most sensitive to the projected future climate changes, and the ensemble median changes in field pea yield range from a decrease of 12% to a decrease of 45%, depending on location. These results highlight the importance of research and policy to support strategies for adapting to climate change, such as advances in agronomy, soil moisture conservation, seasonal climate forecasting and breeding new crop varieties
Annual estimates of occupancy for bryophytes, lichens and invertebrates in the UK, 1970–2015
Here, we determine annual estimates of occupancy and species trends for 5,293 UK bryophytes, lichens, and invertebrates, providing national scale information on UK biodiversity change for 31 taxonomic groups for the time period 1970 to 2015. The dataset was produced through the application of a Bayesian occupancy modelling framework to species occurrence records supplied by 29 national recording schemes or societies (n = 24,118,549 records). In the UK, annual measures of species status from fine scale data (e.g. 1 × 1 km) had previously been limited to a few taxa for which structured monitoring data are available, mainly birds, butterflies, bats and a subset of moth species. By using an occupancy modelling framework designed for use with relatively low recording intensity data, we have been able to estimate species trends and generate annual estimates of occupancy for taxa where annual trend estimates and status were previously limited or unknown at this scale. These data broaden our knowledge of UK biodiversity and can be used to investigate variation in and drivers of biodiversity change
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