Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Transp Policy (Oxf) ; 111: 53-62, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36568351

RESUMO

COVID-19 has upended travel across the world, disrupting commute patterns, mode choices, and public transit systems. In the United States, changes to transit service and reductions in passenger volume due to COVID-19 are lasting longer than originally anticipated. In this paper we examine the impacts of the COVID-19 pandemic on individual travel behavior across the United States. We analyze mobility data from Janurary to December 2020 from a sample drawn from a nationwide smartphone-based panel curated by a private firm, Embee Mobile. We combine this with a survey that we administered to that sample in August 2020. Our analysis provides insight into travel patterns and the immediate impacts of the COVID-19 pandemic on transit riders. We investigate three questions. First, how do transit riders differ socio-demographically from non-riders? Second, how has the travel behavior of transit riders changed due to the pandemic in comparison to non-riders, controlling for other factors? And third, how has this travel behavior varied across different types of transit riders? The travel patterns of transit riders were more significantly disrupted by the pandemic than the travel of non-riders, as measured by the average weekly number of trips and distance traveled before and after the onset of the pandemic. This was calculated using GPS traces from panel member smartphones. Our survey of the panel revealed that of transit riders, 75% reported taking transit less since the pandemic, likely due to a combination of being affected by transit service changes, concerns about infection risk on transit, and trip reductions due to shelter-in-place rules. Less than 10 percent of transit riders in our sample reported that they were comfortable using transit despite COVID-19 infection risk, and were not affected by transit service reductions. Transit riders were also more likely to have changed their travel behavior in other ways, including reporting an increase in walking. However, lower-income transit riders were different from higher-income riders in that they had a significantly smaller reduction in the number of trips and distance traveled, suggesting that these lower-income households had less discretion over the amount of travel they carried out during the pandemic. These results have significant implications for understanding the way welfare has been affected for transportation-disadvantaged populations during the course of the pandemic, and insight into the recovery of U.S. transit systems. The evidence from this unique dataset helps us understand the future effects of the pandemic on transit riders in the United States, either in further recovery from the pandemic with the anticipated effects of mass vaccination, or in response to additional waves of COVID-19 and other pandemics.

2.
Eur J Nutr ; 59(2): 825-833, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31591650

RESUMO

PURPOSE: Poor sperm quality is a major contributor to infertility in heterosexual couples, but at present there are few empirical therapies. Several studies have examined the role of dietary factors and data from randomized controlled trials suggest that oral antioxidant therapy can improve some sperm parameters. Health benefits of lycopene supplementation have been proposed for a variety of health conditions and here we examine whether it can help improve sperm quality. This study aimed to investigate the effect of 14 mg daily lactolycopene for 12 weeks on semen quality in healthy men. METHODS: Sixty healthy male participants were recruited and randomized to this double-blind, placebo-controlled parallel study and received either 14 mg/d lactolycopene or a placebo for 12 weeks. The primary endpoint was a change in motile sperm concentration. Secondary endpoints were all other aspects of sperm quality, including the level of sperm DNA damage. RESULTS: Fifty-six men completed the intervention and the level of plasma lycopene was significantly increased in the men randomized to receive lycopene supplementation. There was no significant change in the primary endpoint (motile sperm concentration) post-intervention (p = 0.058). However, the proportion of fast progressive sperm (p = 0.006) and sperm with normal morphology (p < 0.001) did improve significantly in response to lactolycopene intervention. CONCLUSIONS: Supplementation with 14 mg/d lactolycopene improves sperm motility and morphology in young healthy men. CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE: ISRCTN33248724 http://www.isrctn.com/ISRCTN33248724.


Assuntos
Antioxidantes/farmacologia , Licopeno/farmacologia , Análise do Sêmen/métodos , Espermatozoides/efeitos dos fármacos , Adulto , Antioxidantes/administração & dosagem , Suplementos Nutricionais , Método Duplo-Cego , Humanos , Licopeno/administração & dosagem , Masculino , Adulto Jovem
3.
Biotechnol Lett ; 37(2): 383-9, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25257589

RESUMO

Directed enzyme evolution is now a routine approach to improve desirable biocatalytic properties. When only a low-throughput screen is available to detect improved variants from a mutant gene library, it is imperative that cloning efficiency be maximized during library synthesis to avoid wasting effort screening empty plasmids. To achieve this we developed pUCXKT, a gain-of-function positive selection expression vector. Insertion of genes amplified using a specialized downstream PCR primer restores key regulatory and genetic elements necessary for co-expression of a kanamycin resistance marker adjacent to the pUCXKT cloning region. We show that pUCXKT enables 100 % cloning efficiency as well as high-level expression of inserted genes. Unlike previous positive selection expression plasmids, the strategy we used to design pUCXKT is readily adaptable to different vector backbones, antibiotic marker genes, and multiple cloning regions.


Assuntos
Clonagem Molecular/métodos , Farmacorresistência Bacteriana/genética , Vetores Genéticos/genética , Plasmídeos/genética , Evolução Molecular Direcionada , Escherichia coli/genética
4.
Public Underst Sci ; 28(5): 554-571, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30895916

RESUMO

This study explores the relationships between scientists, science communicators and science journalists in Australia. Building upon a smaller previous study, this article provides an overview of the science media landscape across a nation through the use of semi-structured interviews with members of stakeholder groups. Although relationships between each of the groups are generally positive, a lack of clear understanding of the professional practice and cultures of the different groups sometimes appear to hinder positive interactions. Many scientists continue to lament the need for journalists to understand more science, yet very few make similar comments about the need for scientists to know more about media. Refocusing on sharing the responsibility for science reporting may be a means of bridging the identified cultural divide.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA