3,516 research outputs found
Asymptotically linear fractional Schrodinger equations
By exploiting a variational technique based upon projecting over the Pohozaev
manifold, we prove existence of positive solutions for a class of nonlinear
fractional Schrodinger equations having a nonhomogenous nonautonomous
asymptotically linear nonlinearity.Comment: 24 page
On fractional p-Laplacian problems with weight
We investigate the existence of nonnegative solutions for a nonlinear problem
involving the fractional p-Laplacian operator. The problem is set on a
unbounded domain, and compactness issues have to be handled.Comment: 10 page
Henri Temianka Correspondence; (lehrer)
https://digitalcommons.chapman.edu/temianka_correspondence/2302/thumbnail.jp
Phenomic and Genetic Controls of the Drought Stress Response in Sorghum
Drought, one of the most common abiotic stressors, is a result of the precipitation and temperature fluctuations influenced by climate change. As consistent weather patterns are crucial for the maintenance of crop yield, drought threatens food security through its impact on plant growth and development. It is essential to ensure the quality, availability, and affordability of grain-based products in the face of climate change due to expectations of population growth. Therefore, shedding light on the mechanisms associated with drought tolerance is integral to maintaining agricultural production under water-limited conditions. My dissertation work aimed to uncover the morphological, physiological, and genetic controls of drought resistance in Sorghum, a C4 grain crop grown for food, feed, and biofuel. In Chapter 3, two Sorghum bicolor accessions that differ in their pre-flowering responses to drought were evaluated following long-term drought exposure across juvenile and adult vegetative stages. Findings from this work emphasized accession-specific responses to drought, indicating that morphological/histological and physiological strategies both play roles in promoting hydraulic safety in response to drought, and these mechanisms may be mutually exclusive. Chapter 4 expanded upon the findings of Chapter 3 by uncovering the evolutionary origins of the morphological and physiological responses associated with drought exposure. Using quantitative trait loci (QTL) mapping in a Sorghum recombinant inbred line (RIL) population, eight QTL unique for drought exposure were detected. S. bicolor alleles controlled reductions in height and enhanced aboveground biomass, emphasizing the impact of grain Sorghum varieties (i.e. TX7000) on drought-responsive phenotypes. These biological impacts may be influenced by the candidate genes with these QTL, specifically those involved in reproductive processes. These gene products facilitate grain production and may promote early flowering, a common drought escape mechanism that influences the transition into reproduction before stress becomes too severe. Physiologically, S. bicolor alleles increased leaf temperature while Sorghum propinquum alleles increased relative water content; these species-specific strategies reflect their variable belowground growth and impact of domestication on drought-responsive phenotypes. The QTL detected for relative water content and leaf temperature contained genes involved in auxin and abscisic acid (ABA) synthesis and signaling. In addition to playing roles in root development and water uptake, phytohormones can also affect aboveground responses, such as growth and stomatal closure. Therefore, our findings highlight the contribution of plant hormones to root-to-shoot communication and water uptake and loss through both above- and belowground strategies. The relationship between above- and belowground responses and hormone signaling was explored further in Chapter 5. Using the same Sorghum RIL population, five QTL for belowground responses to drought exposure were identified. Three of these QTL co-localized on chromosome four and with a root biomass QTL detected in this same population evaluated under salinity stress, suggesting shared genetic control of belowground traits under osmotic stress. Further, these traits were all controlled by S. bicolor alleles. This control demonstrated that root system architecture is reorganized under osmotic stress by the domesticated parent to favor vertical growth while also increasing root biomass, suggesting a main goal of enhanced water uptake in the osmotic stress response. Candidate genes within these QTL were associated with root development and hormone synthesis/recognition, contributing additional support to the allelic effects described in this work, as well as to the role of water acquisition described in Chapter 4. Genes within the two remaining QTL detected in the drought population were also involved in plant hormone responses, specifically abscisic acid (ABA). Genes encoding pentatricopeptide repeat (PPR)-containing proteins and Late Embryogenesis Abundant- like (LEA) proteins were identified in these regions. PPRâs have established roles in ABA signaling in Arabidopsis and were also shown to be up-regulated in response to heat and drought stress in Sorghum. Further, LEA proteins are induced upon ABA and osmotic stress exposure, and function as molecular chaperones. Altogether, these findings further highlight the contribution of phytohormones in drought resistance, particularly through intricate signal cascades that influence plant functioning under drought, at the morphological, physiological, and molecular levels
Can we have allergen-free foods?
Biotechnology can be used to reduce allergenicity. Much attention has been focused on the possibility that modification of foods through recombinant DNA technology could unintentionally introduce new allergens but developers and regulators take steps to assess allergenicity of novel proteins. However it is also possible to reduce allergenicity of foods by determining which proteins are responsible for the allergic reaction and then to alter them so that they no longer trigger an immune response in sensitive individuals. While it may not be possible to alter all of the allergenic proteins in some foods, there is potential to open up a whole new range of foods for those who cannot consume them now
Orientational order on curved surfaces - the high temperature region
We study orientational order, subject to thermal fluctuations, on a fixed
curved surface. We derive, in particular, the average density of zeros of
Gaussian distributed vector fields on a closed Riemannian manifold. Results are
compared with the density of disclination charges obtained from a Coulomb gas
model. Our model describes the disordered state of two dimensional objects with
orientational degrees of freedom, such as vector ordering in Langmuir
monolayers and lipid bilayers above the hexatic to fluid transition.Comment: final version, 13 Pages, 2 figures, uses iopart.cl
Psychological interventions in asthma
Asthma is a multifactorial chronic respiratory disease characterised by recurrent episodes of airway obstruction. The current management of asthma focuses principally on pharmacological treatments, which have a strong evidence base underlying their use. However, in clinical practice, poor symptom control remains a common problem for patients with asthma. Living with asthma has been linked with psychological co-morbidity including anxiety, depression, panic attacks and behavioural factors such as poor adherence and suboptimal self-management. Psychological disorders have a higher-than-expected prevalence in patients with difficult-to-control asthma. As psychological considerations play an important role in the management of people with asthma, it is not surprising that many psychological therapies have been applied in the management of asthma. There are case reports which support their use as an adjunct to pharmacological therapy in selected individuals, and in some clinical trials, benefit is demonstrated, but the evidence is not consistent. When findings are quantitatively synthesised in meta-analyses, no firm conclusions are able to be drawn and no guidelines recommend psychological interventions. These inconsistencies in findings may in part be due to poor study design, the combining of results of studies using different interventions and the diversity of ways patient benefit is assessed. Despite this weak evidence base, the rationale for psychological therapies is plausible, and this therapeutic modality is appealing to both patients and their clinicians as an adjunct to conventional pharmacological treatments. What are urgently required are rigorous evaluations of psychological therapies in asthma, on a par to the quality of pharmaceutical trials. From this evidence base, we can then determine which interventions are beneficial for our patients with asthma management and more specifically which psychological therapy is best suited for each patient
On the Core of Dynamic Cooperative Games
We consider dynamic cooperative games, where the worth of coalitions varies
over time according to the history of allocations. When defining the core of a
dynamic game, we allow the possibility for coalitions to deviate at any time
and thereby to give rise to a new environment. A coalition that considers a
deviation needs to take the consequences into account because from the
deviation point on, the game is no longer played with the original set of
players. The deviating coalition becomes the new grand coalition which, in
turn, induces a new dynamic game. The stage games of the new dynamical game
depend on all previous allocation including those that have materialized from
the deviating time on.
We define three types of core solutions: fair core, stable core and credible
core. We characterize the first two in case where the instantaneous game
depends on the last allocation (rather than on the whole history of
allocations) and the third in the general case. The analysis and the results
resembles to a great extent the theory of non-cooperative dynamic games.Comment: 25 page
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