1,281 research outputs found
Dry matter and nitrogen accumulation by standard height and semi-dwarf barley isotypes
Para avaliar o movimento do nitrogênio do solo para a planta e dentro desta, estudos de acúmulo de matéria seca e de N são necessários. O objetivo deste trabalho foi o de estudar o efeito de 30, 60, 90 e 120 kg/ha de N no acúmulo de matéria seca e N em oito genótipos de cevada cervejeira (quatro com altura normal e quatro com altura reduzida, mutantes de cada um dos normais), e duas testemunhas. Verificou-se variabilidade entre os genótipos no acúmulo de matéria seca até a antese e na transferência desta para o grão. Foram observadas diferenças entre os genótipos no acúmulo de N até a antese (de 36,6 a 52,9 mg N/planta), após a antese (de -2,3 a 10,8 mg N/planta) e no total de N acumulado na planta (de 69 a 149,2 mg N/planta em 1987 e 41,3 a 56,5 mg N/planta em 1989). Diferenças consistentes foram observadas, entre os isótipos pares, no N acumulado após antese e no N total, ambos maiores nos isótipos de altura normal. Verificou-se, também, variabilidade entre os genótipos na remobilização do N para o grão. Discutem-se as relações entre distribuição de matéria seca e N na planta.To assess nitrogen movement from the soil into the plant and within the plant, studies of dry matter and N accumulation are necessary. The objective of this experiment was to study the effect of 30, 60, 90 and 120 kg of N/ha on dry matter and N accumulation by four standard height-semi-dwarf normal mutant malting barley isotype pairs (Morex, Hazen, Norbert, Andre) and two check cultivars: Steptoe and Klages. Considerable differences among genotypes on dry matter accumulation until anthesis and dry matter lost during grain filling period were observed. Genotypic differences for pre-anthesis (range: 36.6 to 52.9 mg N/plant) and post-anthesis (range: -2.3 to 10.8 mg N/plant) N accumulation and in total N accumulation (range: 69 to 149.2 mg N/plant in 1987 and 41.3 to 56.5 mg N/ha in 1989) were observed. Within the isotype pairs, consistent differences were detected for post-anthesis and total N accumulation both favoring the standard isotypes. These differences were not affected by fertilizer N levels. Genotypic differences in N remobilization into the grain were also observed. Relationship between N and dry matter partitioning are discussed
Uncertainty quantification for CO2 sequestration and enhanced oil recovery
This study develops a statistical method to perform uncertainty
quantification for understanding CO2 storage potential within an enhanced oil
recovery (EOR) environment at the Farnsworth Unit of the Anadarko Basin in
northern Texas. A set of geostatistical-based Monte Carlo simulations of
CO2-oil-water flow and reactive transport in the Morrow formation are conducted
for global sensitivity and statistical analysis of the major uncertainty
metrics: net CO2 injection, cumulative oil production, cumulative gas (CH4)
production, and net water injection. A global sensitivity and response surface
analysis indicates that reservoir permeability, porosity, and thickness are the
major intrinsic reservoir parameters that control net CO2 injection/storage and
oil/gas recovery rates. The well spacing and the initial water saturation also
have large impact on the oil/gas recovery rates. Further, this study has
revealed key insights into the potential behavior and the operational
parameters of CO2 sequestration at CO2-EOR sites, including the impact of
reservoir characterization uncertainty; understanding this uncertainty is
critical in terms of economic decision making and the cost-effectiveness of CO2
storage through EOR.Comment: 9 pages, 6 figures, in press, Energy Procedia, 201
Is There a Relationship Between the Concentration of Same-Sex Couples and Tobacco Retailer Density?
Tobacco use is markedly higher among lesbian, gay, and bisexual populations than heterosexuals. Higher density of tobacco retailers is found in neighborhoods with lower income and more racial/ethnic minorities. Same-sex couples tend to live in similar neighborhoods, but the association of this demographic with tobacco retailer density has not been examined
Relationship Between Tobacco Retailers’ Point-of-Sale Marketing and the Density of Same-Sex Couples, 97 U.S. Counties, 2012
The reasons for higher rates of smoking among lesbian, gay, and bisexual (LGB) people than among heterosexual people are not well known. Research on internal migration and neighborhood selection suggests that LGB people are more likely to live in neighborhoods where the tobacco industry has historically targeted their marketing efforts (lower income, more racial/ethnic diversity). We used multi-level models to assess the relationship between the rate of same-sex couples per 1000 coupled households and 2012 marketing characteristics of tobacco retailers (n = 2231) in 1696 census tracts in 97 U.S. counties. We found no evidence of tobacco marketing at retailers differing by same-sex couple rates in census tracts with the exception of three findings in the opposite direction of our hypotheses: a small, significant positive relationship for the rate of same-sex male couples and the price of Newport Green (mentholated) cigarettes. For male and female same-sex couples, we also found a small negative relationship between tobacco advertisements and same-sex household rate. Tobacco retailers’ tobacco marketing characteristics do not differ substantially by the rate of same-sex couples in their neighborhood in ways that would promote LGB health disparities. Further work is needed to determine if these patterns are similar for non-partnered LGB people
Nitrogen use by standard height and semi-dwarf barley isotypes
Considerando que uma quantidade substancial do nitrogênio utilizado para produção de grãos de cereais pode ser perdida por lixiviação ou erosão, o desenvolvimento de cultivares com maior eficiência na utilização deste nutriente bem como um melhor manejo do mesmo são, sem dúvida, práticas desejáveis em uma agricultura auto-sustentável. O objetivo do presente trabalho foi de estudar o efeito de 30, 60, 90 e 120 kg/ha de N na eficiência de uso de nitrogênio de oito genótipos de cevada cervejeira (quatro com altura normal e quatro semi-anões, mutantes de cada um dos normais). Foram observadas diferenças entre os genótipos na remobilização e na eficiência da remobilização de nitrogênio para o grão na eficiência de utilização, absorção e uso de nitrogênio. De modo geral, os genótipos de estatura normal apresentaram valores maiores para todos os parâmetros de uso de N. A remobilização de nitrogênio para o grão aumentou com as doses crescentes de N enquanto a utilização e eficiência de uso decresceram, tanto nos genótipos de estatura normal como nos semi-anões. São discutidas as relações entre o uso de nitrogênio e o rendimento de grãos.Considering that a substantial amount of N applied in cereal production may be lost by leaching or erosion, the development of cultivars with increased efficiency to utilize N and more efficient N management practices are desirable. The objective of this experiment was to study the effect of 30, 60, 90 and 120 kg of N/ha on N use by four standard height semi-dwarf normal-mutant malting barley isotype pairs (Morex, Hazen, Norbert, Andre). Genotypic differences in N remobilization in the grain, remobilization efficiency, utilization efficiency and uptake efficiency and N use efficiency were observed. The standard isotypes with few exceptions had higher values for all of these N traits. Nitrogen remobilization in the grain increased with increasing N fertilization while N utilization and N use efficiency decreased in both standard and semi-dwarf isotypes. Nitrogen use and grain yield relations are discussed
Highly active and stable stepped Cu surface for enhanced electrochemical CO₂ reduction to C₂H₄
Electrochemical CO₂ reduction to value-added chemical feedstocks is of considerable interest for renewable energy storage and renewable source generation while mitigating CO₂ emissions from human activity. Copper represents an effective catalyst in reducing CO₂ to hydrocarbons or oxygenates, but it is often plagued by a low product selectivity and limited long-term stability. Here we report that copper nanowires with rich surface steps exhibit a remarkably high Faradaic efficiency for C₂H₄ that can be maintained for over 200 hours. Computational studies reveal that these steps are thermodynamically favoured compared with Cu(100) surface under the operating conditions and the stepped surface favours C₂ products by suppressing the C₁ pathway and hydrogen production
Highly active and stable stepped Cu surface for enhanced electrochemical CO₂ reduction to C₂H₄
Electrochemical CO₂ reduction to value-added chemical feedstocks is of considerable interest for renewable energy storage and renewable source generation while mitigating CO₂ emissions from human activity. Copper represents an effective catalyst in reducing CO₂ to hydrocarbons or oxygenates, but it is often plagued by a low product selectivity and limited long-term stability. Here we report that copper nanowires with rich surface steps exhibit a remarkably high Faradaic efficiency for C₂H₄ that can be maintained for over 200 hours. Computational studies reveal that these steps are thermodynamically favoured compared with Cu(100) surface under the operating conditions and the stepped surface favours C₂ products by suppressing the C₁ pathway and hydrogen production
A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17a
The merging neutron star gravitational wave event GW170817 has been observed
throughout the entire electromagnetic spectrum from radio waves to
-rays. The resulting energetics, variability, and light curves are
shown to be consistent with GW170817 originating from the merger of two neutron
stars, in all likelihood followed by the prompt gravitational collapse of the
massive remnant. The available -ray, X-ray and radio data provide a
clear probe for the nature of the relativistic ejecta and the non-thermal
processes occurring within, while the ultraviolet, optical and infrared
emission are shown to probe material torn during the merger and subsequently
heated by the decay of freshly synthesized -process material. The simplest
hypothesis that the non-thermal emission is due to a low-luminosity short
-ray burst (sGRB) seems to agree with the present data. While low
luminosity sGRBs might be common, we show here that the collective prompt and
multi-wavelength observations are also consistent with a typical, powerful sGRB
seen off-axis. Detailed follow-up observations are thus essential before we can
place stringent constraints on the nature of the relativistic ejecta in
GW170817.Comment: 9 pages, 5 figures, accepted to ApJ Letter
An In Vivo Screen Identifies PYGO2 as a Driver for Metastatic Prostate Cancer
Advanced prostate cancer displays conspicuous chromosomal instability and rampant copy number aberrations, yet the identity of functional drivers resident in many amplicons remain elusive. Here, we implemented a functional genomics approach to identify new oncogenes involved in prostate cancer progression. Through integrated analyses of focal amplicons in large prostate cancer genomic and transcriptomic datasets as well as genes upregulated in metastasis, 276 putative oncogenes were enlisted into an in vivo gain-of-function tumorigenesis screen. Among the top positive hits, we conducted an in-depth functional analysis on Pygopus family PHD finger 2 (PYGO2), located in the amplicon at 1q21.3. PYGO2 overexpression enhances primary tumor growth and local invasion to draining lymph nodes. Conversely, PYGO2 depletion inhibits prostate cancer cell invasion in vitro and progression of primary tumor and metastasis in vivo In clinical samples, PYGO2 upregulation associated with higher Gleason score and metastasis to lymph nodes and bone. Silencing PYGO2 expression in patient-derived xenograft models impairs tumor progression. Finally, PYGO2 is necessary to enhance the transcriptional activation in response to ligand-induced Wnt/β-catenin signaling. Together, our results indicate that PYGO2 functions as a driver oncogene in the 1q21.3 amplicon and may serve as a potential prognostic biomarker and therapeutic target for metastatic prostate cancer.Significance: Amplification/overexpression of PYGO2 may serve as a biomarker for prostate cancer progression and metastasis. Cancer Res; 78(14); 3823-33. ©2018 AACR
Identification and Characterization of \u3cem\u3eOGG1\u3c/em\u3e Mutations in Patients with Alzheimer\u27s Disease
Patients with Alzheimer\u27s disease (AD) exhibit higher levels of 8-oxo-guanine (8-oxoG) DNA lesions in their brain, suggesting a reduced or defective 8-oxoG repair. To test this hypothesis, this study investigated 14 AD patients and 10 age-matched controls for mutations of the major 8-oxoG removal gene OGG1. Whereas no alterations were detected in any control samples, four AD patients exhibited mutations in OGG1, two carried a common single base (C796) deletion that alters the carboxyl terminal sequence of OGG1, and the other two had nucleotide alterations leading to single amino acid substitutions. In vitro biochemical assays revealed that the protein encoded by the C796-deleted OGG1 completely lost its 8-oxoG glycosylase activity, and that the two single residue-substituted OGG1 proteins showed a significant reduction in the glycosylase activity. These results were consistent with the fact that nuclear extracts derived from a limited number of AD patients with OGG1 mutations exhibited greatly reduced 8-oxoG glycosylase activity compared with age-matched controls and AD patients without OGG1 alterations. Our findings suggest that defects in OGG1 may be important in the pathogenesis of AD in a significant fraction of AD patients and provide new insight into the molecular basis for the disease
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