772 research outputs found
Developing drought tolerant crops: hopes and challenges in an exciting journey
Under increasing water scarcity, food production for an increasing population is a global challenge. Maintaining crop production under limiting water supply is a common problem in agriculture, which is best addressed by the coordinated efforts of geneticists, physiologists and agronomists. This special issue is a selection of oral and poster presentations at the InterDrought IV conference, held in Perth (2–6 September 2013). These papers provide a broad, multidisciplinary view on the way to develop improved cultivars in the face of water deficit, providing the conference highlight: an integration of views from different disciplinary angles, generating constructive debate that was not buried in disciplinary silos. More specifically, the topics covered deal with the challenge of adaptation implicit in genotype-by-environment interaction, bring new perspectives on root systems and water productivity, and review the challenges and opportunities provided by crop management, genomic and transgenic approaches to cultivar improvement
Review: An integrated framework for crop adaptation to dry environments: Responses to transient and terminal drought
As the incidence of water deficit and heat stress increases in many production regions there is an increasing requirement for crops adapted to these stresses. Thus it is essential to match water supply and demand, particularly during grain-filling. Here we integrate Grime’s ecological strategies approach with traditional drought resistance/yield component frameworks describing plant responses to water deficit. We demonstrate that water use is a function of both short and longer term trade-offs between competing demands for carbon. Agricultural crop adaptation is based on escape. Rapid growth rates and high reproductive investment maximize yield, and stress is avoided through a closely regulated, climate-appropriate annual phenology. Crops have neither the resources nor morphological capacity to withstand long periods of intense water deficit. Thus, under terminal drought, yield potential is traded off against drought escape, such that drought postponing and/or tolerance traits which extend the growing season and/or divert source from reproductive sinks are maladaptive. However, these traits do play a supporting role against transient water deficits, allowing longer season cultivars to survive by mining water through deeper roots, or restricting transpiration. Recognizing these trade-offs made within escape-strategy limits will allow breeders to integrate complementary adaptive traits to transient and terminal water deficits
A survey on Routing Protocols in Wireless Sensor Networks
In ad-hoc WSN is a collection of mobile nodes that are dynamically and randomly located in such a manner that the interconnections between nodes are changing on a continual basis. The dynamic nature of these networks demands new set of network routing strategy protocols to be implemented in order to provide efficient end-to end communication. Moreover, such issues are very critical due to severe resource constraints like efficient energy utilization, lifetime of network, and drastic environmental conditions in WSNs. Neither hop-by-hop nor neither direct reach ability is possible in case of WSNs. In order to facilitate communication within the network, a routing protocol is used. In this paper we have carried out an extensive survey on WSN protocols based on structure of network, routing protocol of network & clustering techniques of routing protocols
Primary Meningeal Rhabdomyosarcoma
Primary meningeal rhabdomyosarcoma is a rare primary brain malignancy, with scant case reports. While most reports of primary intracranial rhabdomyosarcoma occur in pediatric patients, a handful of cases in adult patients have been reported in the medical literature. We report the case of a 44-year-old male who developed primary meningeal rhabdomyosarcoma. After developing episodes of right lower extremity weakness, word finding difficulty, and headaches, a brain magnetic resonance imaging (MRI) demonstrated a vertex lesion with radiographic appearance of a meningeal-derived tumor. Subtotal surgical resection was performed due to sagittal sinus invasion and initial pathology was interpreted as an anaplastic meningioma. Re-review of pathology demonstrated rhabdomyosarcoma negative for alveolar translocation t(2;13). Staging studies revealed no evidence of disseminated disease. He was treated with stereotactic radiotherapy with concurrent temozolamide to be followed by vincristine, actinomycin-D, and cyclophosphamide (VAC) systemic therapy
Executive summary of AAPM Report Task Group 113: Guidance for the physics aspects of clinical trials
The charge of AAPM Task Group 113 is to provide guidance for the physics aspects of clinical trials to minimize variability in planning and dose delivery for external beam trials involving photons and electrons. Several studies have demonstrated the importance of protocol compliance on patient outcome. Minimizing variability for treatments at different centers improves the quality and efficiency of clinical trials. Attention is focused on areas where variability can be minimized through standardization of protocols and processes through all aspects of clinical trials. Recommendations are presented for clinical trial designers, physicists supporting clinical trials at their individual clinics, quality assurance centers, and manufacturers.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146453/1/acm212384_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146453/2/acm212384.pd
Investigation of common, low-frequency and rare genome-wide variation in anorexia nervosa
Correction: Volume: 23 Issue: 9 DOI: 10.1038/mp.2017.202 Published: SEP 2018Anorexia nervosa (AN) is a complex neuropsychiatric disorder presenting with dangerously low body weight, and a deep and persistent fear of gaining weight. To date, only one genome-wide significant locus associated with AN has been identified. We performed an exome-chip based genome-wide association studies (GWAS) in 2158 cases from nine populations of European origin and 15 485 ancestrally matched controls. Unlike previous studies, this GWAS also probed association in low-frequency and rare variants. Sixteen independent variants were taken forward for in silico and de novo replication (11 common and 5 rare). No findings reached genome-wide significance. Two notable common variants were identified: rs10791286, an intronic variant in OPCML (P = 9.89 x 10(-6)), and rs7700147, an intergenic variant (P = 2.93 x 10(-5)). No low-frequency variant associations were identified at genome-wide significance, although the study was well-powered to detect low-frequency variants with large effect sizes, suggesting that there may be no AN loci in this genomic search space with large effect sizes.Peer reviewe
Plasma Membrane Lipids Associated with Genetic Variability in Freezing Tolerance and Cold Acclimation of Solanum Species
Depression and Oxidative Stress: Results From a Meta-Analysis of Observational Studies
To perform a systematic review and meta-analysis that quantitatively tests and summarizes the hypothesis that depression results in elevated oxidative stress and lower antioxidant levels
IMRT commissioning: multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119.
AAPM Task Group 119 has produced quantitative confidence limits as baseline expectation values for IMRT commissioning. A set of test cases was developed to assess the overall accuracy of planning and delivery of IMRT treatments. Each test uses contours of targets and avoidance structures drawn within rectangular phantoms. These tests were planned, delivered, measured, and analyzed by nine facilities using a variety of IMRT planning and delivery systems. Each facility had passed the Radiological Physics Center credentialing tests for IMRT. The agreement between the planned and measured doses was determined using ion chamber dosimetry in high and low dose regions, film dosimetry on coronal planes in the phantom with all fields delivered, and planar dosimetry for each field measured perpendicular to the central axis. The planar dose distributions were assessed using gamma criteria of 3%/3 mm. The mean values and standard deviations were used to develop confidence limits for the test results using the concept confidence limit = /mean/ + 1.96sigma. Other facilities can use the test protocol and results as a basis for comparison to this group. Locally derived confidence limits that substantially exceed these baseline values may indicate the need for improved IMRT commissioning
Midlife systemic inflammation is associated with frailty in later life: The ARIC study
Background: Evidence suggests that systemic inflammation may have a mechanistic role in age-related frailty, yet prospective data is limited. We examined whether systemic inflammation during midlife was associated with late-life frailty within the community-based Atherosclerosis Risk in Communities Study. Methods: Plasma levels of four inflammatory markers (fibrinogen, von Willebrand factor, and Factor VIII, and white blood cell count) were measured during Visit 1 (1987-1989; mean age: 52 [5]), standardized into z-scores, and combined to create an inflammation composite score. High-sensitivity C-reactive protein (CRP) was measured 3 (Visit 2, 1990-1992) and 9 (Visit 4, 1996-1999) years later. Frailty was evaluated in 5,760 participants during late life (Visit 5, 2011-2013; mean age: 75 [5]). Analyses were adjusted for demographic and physiological variables, and midlife medical comorbidity using logistic regression. Results: A 1 SD increase in midlife inflammation composite score was associated with higher odds of frailty 24 years later (odds ratio [OR] = 1.39, 95% confidence interval [CI]: 1.18-1.65). Similarly, each standard deviation increase in Visit 2 CRP (OR = 1.24, 95% CI: 1.09-1.40) and Visit 4 CRP (OR = 1.35, 95% CI: 1.19-1.53) was associated with a higher odds of frailty 21 and 15 years later. Participants who maintained elevated CRP (≥3 mg/L) at Visits 2 and 4 or transitioned to a state of elevated CRP during this period were more likely to subsequently meet frailty criteria compared to those who maintained low CRP. These associations were stronger among white, compared to African American, participants (p-interactions <.038). Conclusions: Systemic inflammation during midlife may independently promote pathophysiological changes underlying frailty in a subset of the population
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