6,160 research outputs found
Natural patterns of plant epigenetic variation: Understanding the link between DNA methylation and environmental conditions
In the last couple of decades, extreme weather events have been increasing, exceeding plantsâ tolerance thresholds, and driving mass mortalities in many tree species. Furthermore, many studies suggest that due to their longevity, trees are not able to adapt rapidly enough to keep pace with global climate change. Understanding how trees respond to such weather events and other environmental conditions (such as biotic stress) has thus become crucial for conservation policies and forest management programs. To cope with unpredictable environmental conditions, plants have evolved the ability to alter their physiology, morphology, or development or, in other words, the ability to produce different phenotypes from one genotype. This ability is called phenotypic plasticity, and it plays a major role in plant adaptation. Three factors have been suggested to increase phenotypic variability and thus potentially the resilience of tree populations: intraspecific genetic variability, (micro-)environmental variation, and epigenetic variation. Indeed, a growing body of literature suggests that epigenetic variation might contribute to local adaptation of natural plant populations. Epigenetic mechanisms, such as DNA methylation, can in fact quickly alter phenotypes in response to environmental changes. Variation in DNA methylation can be under genetic control, arise stochastically, or be induced by environmental conditions. Furthermore, phenotypic changes induced by epigenetic variation can be inherited across several generations (especially across clonal generations), suggesting that variation in DNA methylation might contribute to heritable phenotypic variation and, eventually, to adaptation. Although considerable progress has been made in recent years, the link between epigenetic variation and phenotypic variation remains poorly understood
Star formation in Seyfert galaxies
An analysis of the IRAS data for a sample of classical (optically selected) Seyfert galaxies is presented. The IRAS fluxes at 25 micron, 60 micron, and 100 micron are found to be uncorrelated or only very weakly correlated with the UV/Optical continuum flux and the near and mid IR flux at 3.5 and 10 microns. To investigate the possibility that star formation accounts for the far IR flux, the IRAS measurements for the Seyfert galaxies are compared to IRAS observations of a sample of normal spiral galaxies, and a sample of Starburst galaxies. It is shown that the far IR luminosities and far IR colors of Seyfert galaxies are indistinguishable from those of the Starburst galaxies. Besides, normal galaxies are an order of magnitude less luminous than both the Seyfert and the Starburst galaxies. This indicates that star formation produces the bulk of the far infrared emission in Seyfert galaxies
Comparison of alumni donors and alumni nondonors on selected demographic, educational and involvement factors
This study compared College of Agriculture (COA) alumni of a research university (RU/VH) in the Southern U.S. on selected demographic characteristics and contact information by whether or not the alumni are donors to the university. The target population was COA graduates from 1862 Land Grant Universities located in the Southern portion of the United States. The accessible population was Louisiana State University (LSU) COA alumni graduates. The sample was alumni who completed their degree program from the years 1950 through 2000. The instrument used was the Tiger Advancement Information Lookup System (TAILS) database. Universities have become burdened by financial instability due to the increasing number of students enrolled in college and state budget cuts to higher education. Alumni donations acquired through fund raising efforts have been put in the forefront of raising money to support and sustain the mission of higher education. Targeting alumni is a way to increase funding and endowments for support to higher education. Alumni have become an integral component in the fund raising scheme of higher education. The methodology of this descriptive exploratory study involved downloading alumni data from the university foundation database. The study found that alumni donors and nondonors were different on a number of demographic characteristics. Additionally, models were found explaining number of donations, largest donation, total amount of donation, and total donations specific to agriculture. In addition, a logistical model was identified that correctly classified 84.1% of alumni on donor status. The researcher concluded that non-employment university affiliation and total number of contacts were important explanatory factors. Recommendations included establishment of more affiliation opportunities and increased frequency of contacts with alumni. The researcher recommended increasing non-traditional methods of contact and involving alumni through various forms of affiliation by creating new types, especially within areas identified by this study in the states with cluster groups of 50 or more alumni. Furthermore, the researcher recommended studies on contact information, and non-employment university affiliation be conducted in an effort to increase the percentage of classifying alumni donor status. The researcher recommends student involvement through club affiliation in an effort to build relationships prior to graduation
Proposing Kluyvera georgiana as the Origin of the Plasmid-Mediated Resistance Gene fosA4
A putative fosA gene in Kluyvera georgiana 14751 showed 99% nucleotide identity with plasmid-encoded fosA4. Due to a single-nucleotide insertion translating to a truncated protein, K. georgiana 14751 fosA does not confer fosfomycin resistance. However, analysis of another genome deposit (Kluyvera ascorbata WCH1410) that could be recategorized as K. georgiana after phylogenetic analysis revealed a fosA gene 100% identical to the plasmid-borne fosA4 gene. We suggest that Kluyvera georgiana represents the most probable origin of fosA4.Fil: Rodriguez, Maria Margarita. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de MicrobiologĂa, InmunologĂa y BiotecnologĂa. CĂĄtedra de MicrobiologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Ghiglione, Barbara. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de MicrobiologĂa, InmunologĂa y BiotecnologĂa. CĂĄtedra de MicrobiologĂa; ArgentinaFil: Power, Pablo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de MicrobiologĂa, InmunologĂa y BiotecnologĂa. CĂĄtedra de MicrobiologĂa; ArgentinaFil: Naas, Thierry. HĂŽpital de BicĂȘtre. Service de BactĂ©riologie HygiĂšne; FranciaFil: Gutkind, Gabriel Osvaldo. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de MicrobiologĂa, InmunologĂa y BiotecnologĂa. CĂĄtedra de MicrobiologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Muon diffusion and electronic magnetism in YTiO
We report a SR study in a YTiO single crystal. We observe
slow local field fluctuations at low temperature which become faster as the
temperature is increased. Our analysis suggests that muon diffusion is present
in this system and becomes small below 40 K and therefore incoherent. A
surprisingly strong electronic magnetic signal is observed with features
typical for muons thermally diffusing towards magnetic traps below K and released from them above this temperature. We attribute the traps to
Ti defects in the diluted limit. Our observations are highly relevant to
the persistent spin dynamics debate on TiO pyrochlores and their
crystal quality
Metformin Therapy and Diabetes Prevention in Adolescents Who Are Obese
No studies have addressed the question of whether metformin reduces development of diabetes among adolescents who are obese. Metformin treatment in adolescents who are obese can modestly reduce risk factors for type 2 diabetes, including elevated body mass index (BMI), fasting insulin levels, and fasting glucose levels. (Strength of Recommendation [SOR]: C). However, metformin treatment is associated with nausea, abdominal pain, and diarrhea. (SOR: A). Because of the limited available data, metformin is not recommended for diabetes prevention in adolescents. (SOR: C)
Increased amino acid turnover and myofibrillar protein breakdown in advanced cancer are associated with muscle weakness and impaired physical function
Muscle wasting in cancer negatively affects physical function and quality of life. This study investigates amino acid metabolism and the association with muscle mass and function in patients with cancer.In 16 patients with advanced cancer undergoing chemotherapy and 16 healthy controls, we administered an intravenous pulse and prime of stable amino acid tracers. We took blood samples to measure the Rate of appearance (Ra), whole body production (WBP), clearance (Cl), and post absorptive whole body net protein breakdown (WBnetPB). Plasma amino acid concentrations and enrichments were analysed by LC-MS/MS. We assessed muscle mass, handgrip/leg/respiratory muscle strength and reported physical activity, quality of life, and physical function.Muscle strength was lower in cancer patients than in healthy controls. Total and limb muscle mass, reported physical activity and WBnetPB were comparable. WBP and Cl of tau-methylhistidine, leucine, glutamine and taurine were higher in cancer patients as well as glycine Cl. Amino acid metabolism was correlated with low muscle mass, strength, physical function and quality of life.Myofibrillar protein breakdown and production of amino acids involved in muscle contractility are up regulated in patients with cancer undergoing chemotherapy and related to muscle weakness and reduced physical outcomes
STEM Literacy for ELLs through Service Learning
This presentation features: Rationale, Model of Academic Language Proficiency/ Jim Cumminsâs Quadrant, STEM Literacy for ELLs, ELLS-OPS, Tall grasses and Wildflowers of Nebraska: A Service Learning Experience, UNO Students, Objectives, First Year: 2011-2012, Second Year: 2012-2013, Community Partner: Allwine Prairie, Support from Service Learning Academy, Research Presentations, Literacy Strategies, Service Learning Project Outcomes, Visit to the Prairie, and Future Research
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