293 research outputs found

    Research on plant disease and pest management is essential to sustainable agriculture

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    In the United States, a country with food in great abundance, it is difficult to realize that, were it not for the current level of plant disease and pest management, most human resources would be needed to obtain enough food and other plant and animal products merely to survive. Instead, there are surpluses, markets for many agricultural products are depressed, and funds available for research on plant disease and pest management-and for agricultural research generally-have plateaued or are declining. Why does the United States need more research on plant disease and pest management? Because the health and productivity of the crops and cropping systems upon which the people depend for their own consumption and for export cannot be sustained without continuing research and development. This continued investment is needed to manage ever threatening, changing, and rebounding diseases and pest populations. Moreover, disease and pest management of the future must be improved while simultaneously reducing our dependence on pesticides as one of many steps toward the goal of sustainable agriculture. The goal of plant disease and pest management is to ensure that crops are healthy enough to yield to their full genetic potential within the physical limits imposed by the uncontrolled variables of climate, weather, and soils. Management is defined as limiting damage from diseases or pests to a level at or below an acceptable economic or aesthetic threshold. This process does not require total elimination or eradication of the pest or disease problem

    Research on plant disease and pest management is essential to sustainable agriculture

    Get PDF
    In the United States, a country with food in great abundance, it is difficult to realize that, were it not for the current level of plant disease and pest management, most human resources would be needed to obtain enough food and other plant and animal products merely to survive. Instead, there are surpluses, markets for many agricultural products are depressed, and funds available for research on plant disease and pest management-and for agricultural research generally-have plateaud or are declining. Why does the United States need more research on plant disease and pest management? Because the health and productivity of the crops and cropping systems upon which the people depend for their own consumption and for export cannot be sustained without continuing research and development. This continued investment is needed to manage ever threatening, changing, and rebounding diseases and pest populations. Moreover, disease and pest management of the future must be improved while simultaneously reducing our dependence on pesticides as one of many steps toward the goal of sustainable agriculture. The goal of plant disease and pest management is to ensure that crops are healthy enough to yield to their full genetic potential within the physical limits imposed by the uncontrolled variables of climate, weather, and soils. Management is defined as limiting damage from diseases or pests to a level at or below an acceptable economic or aesthetic threshold. This process does not require total elimination or eradication of the pest or disease problem. Reducing the use of pesticides is a desirable goal, but it depends on continued and increased investments in research on alternatives. For many chemical pesticides, the alternatives either are not yet developed or are less effective than chemicals. This research must be broadly based across the biological, physical, and social sciences. Moreover, the United States and the world depend not only on sustainable agriculture but also on sustainable growth in agriculture to meet a long-term increase in demand for quality and quantity of agricultural products expected from increases in both numbers and economic status of people (Rutan 1992). Furthermore. these increases must \u27be attained at the same time that available agricultural land is decreasing to satisfy other needs such as more land for recreation and urbanization; restoration of some wetlands, grasslands, and woodlands; and diversions of land from farming to other uses. Improved disease and pest management offers one of the few effective means by which the necessary increases in crop productivity can be accomplished while natural resources, including the remaining forests, are protected. These same principles apply to other uses of plants as well, including as ornamentals, for landscapes, and in parks and golf courses

    Challenges to the industrial melt-processing of conductive plastics

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    In this work, we investigate the relationship between the timescales available for polymer mobility during processing and post-processing and the electrical resistivity of melt-processed thermoplastics filled with carbon nanoparticles. Post-process annealing below the glass transition temperature was one avenue explored to uplift electrical conductivity. Detailed analysis of available literature on thermoplastics filled with either graphite nanoplatelets or carbon nanotubes, and of relevant processing data suggests that the required timescale for shaping process or post-processing to obtain conductive material needs to be sufficiently longer than that of the base polymer characteristic relaxation time τd. Four factors have been identified that promote the formation of a conductive filler network in thermoplastics: filler loading content, polymer molar mass, processing temperature and processing timescales

    Anticoagulant rodenticides on our public and community lands: spatial distribution of exposure and poisoning of a rare forest carnivore.

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    Anticoagulant rodenticide (AR) poisoning has emerged as a significant concern for conservation and management of non-target wildlife. The purpose for these toxicants is to suppress pest populations in agricultural or urban settings. The potential of direct and indirect exposures and illicit use of ARs on public and community forest lands have recently raised concern for fishers (Martes pennanti), a candidate for listing under the federal Endangered Species Act in the Pacific states. In an investigation of threats to fisher population persistence in the two isolated California populations, we investigate the magnitude of this previously undocumented threat to fishers, we tested 58 carcasses for the presence and quantification of ARs, conducted spatial analysis of exposed fishers in an effort to identify potential point sources of AR, and identified fishers that died directly due to AR poisoning. We found 46 of 58 (79%) fishers exposed to an AR with 96% of those individuals having been exposed to one or more second-generation AR compounds. No spatial clustering of AR exposure was detected and the spatial distribution of exposure suggests that AR contamination is widespread within the fisher's range in California, which encompasses mostly public forest and park lands Additionally, we diagnosed four fisher deaths, including a lactating female, that were directly attributed to AR toxicosis and documented the first neonatal or milk transfer of an AR to an altricial fisher kit. These ARs, which some are acutely toxic, pose both a direct mortality or fitness risk to fishers, and a significant indirect risk to these isolated populations. Future research should be directed towards investigating risks to prey populations fishers are dependent on, exposure in other rare forest carnivores, and potential AR point sources such as illegal marijuana cultivation in the range of fishers on California public lands

    Patterns of Natural and Human-Caused Mortality Factors of a Rare Forest Carnivore, the Fisher (Pekania pennanti) in California.

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    Wildlife populations of conservation concern are limited in distribution, population size and persistence by various factors, including mortality. The fisher (Pekania pennanti), a North American mid-sized carnivore whose range in the western Pacific United States has retracted considerably in the past century, was proposed for threatened status protection in late 2014 under the United States Endangered Species Act by the United States Fish and Wildlife Service in its West Coast Distinct Population Segment. We investigated mortality in 167 fishers from two genetically and geographically distinct sub-populations in California within this West Coast Distinct Population Segment using a combination of gross necropsy, histology, toxicology and molecular methods. Overall, predation (70%), natural disease (16%), toxicant poisoning (10%) and, less commonly, vehicular strike (2%) and other anthropogenic causes (2%) were causes of mortality observed. We documented both an increase in mortality to (57% increase) and exposure (6%) from pesticides in fishers in just the past three years, highlighting further that toxicants from marijuana cultivation still pose a threat. Additionally, exposure to multiple rodenticides significantly increased the likelihood of mortality from rodenticide poisoning. Poisoning was significantly more common in male than female fishers and was 7 times more likely than disease to kill males. Based on necropsy findings, suspected causes of mortality based on field evidence alone tended to underestimate the frequency of disease-related mortalities. This study is the first comprehensive investigation of mortality causes of fishers and provides essential information to assist in the conservation of this species

    Factors in AIDS Dementia Complex Trial Design: Results and Lessons from the Abacavir Trial

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    OBJECTIVES: To determine the efficacy of adding abacavir (Ziagen, ABC) to optimal stable background antiretroviral therapy (SBG) to AIDS dementia complex (ADC) patients and address trial design. DESIGN: Phase III randomized, double-blind placebo-controlled trial. SETTING: Tertiary outpatient clinics. PARTICIPANTS: ADC patients on SBG for ≥8 wk. INTERVENTIONS: Participants were randomized to ABC or matched placebo for 12 wk. OUTCOME MEASURES: The primary outcome measure was the change in the summary neuropsychological Z score (NPZ). Secondary measures were HIV RNA and the immune activation markers β-2 microglobulin, soluble tumor necrosis factor (TNF) receptor 2, and quinolinic acid. RESULTS: 105 participants were enrolled. The median change in NPZ at week 12 was +0.76 for the ABC + SBG and +0.63 for the SBG groups (p = 0.735). The lack of efficacy was unlikely related to possible limited antiviral efficacy of ABC: at week 12 more ABC than placebo participants had plasma HIV RNA ≤400 copies/mL (p = 0.002). There were, however, other factors. Two thirds of patients were subsequently found to have had baseline resistance to ABC. Second, there was an unanticipated beneficial effect of SBG that extended beyond 8 wk to 5 mo, thereby rendering some of the patients at baseline unstable. Third, there was an unexpectedly large variability in neuropsychological performance that underpowered the study. Fourth, there was a relative lack of activity of ADC: 56% of all patients had baseline cerebrospinal fluid (CSF) HIV-1 RNA <100 copies/mL and 83% had CSF β-2 microglobulin <3 nmol/L at baseline. CONCLUSIONS: The addition of ABC to SBG for ADC patients was not efficacious, possibly because of the inefficacy of ABC per se, baseline drug resistance, prolonged benefit from existing therapy, difficulties with sample size calculations, and lack of disease activity. Assessment of these trial design factors is critical in the design of future ADC trials

    Contesting longstanding conceptualisations of urban green space

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    Ever since the Victorian era saw the creation of “parks for the people,” health and wellbeing benefits have been considered a primary benefit of urban parks and green spaces. Today, public health remains a policy priority, with illnesses and conditions such as diabetes, obesity and depression a mounting concern, notably in increasingly urbanised environments. Urban green space often is portrayed as a nature-based solution for addressing such health concerns. In this chapter, Meredith Whitten investigates how the health and wellbeing benefits these spaces provide are limited by a narrow perspective of urban green space. Whitten explores how our understandings of urban green space remain rooted in Victorian ideals and calls into question how fit for purpose they are in twenty-first-century cities. Calling on empirical evidence collected in three boroughs in London with changing and increasing demographic populations, she challenges the long-held cultural underpinnings that lead to urban green space being portrayed “as a panacea to urban problems, yet treating it as a ‘cosmetic afterthought’” (Whitten, M, Reconceptualising green space: planning for urban green space in the contemporary city. Doctoral thesis, London School of Economics and Political Science, London, U.K. http://etheses.lse.ac.uk/. Accessed 12 Jun 2019, 2019b, p 18)

    Factors in AIDS Dementia Complex Trial Design: Results and Lessons from the Abacavir Trial

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    To determine the efficacy of adding abacavir (Ziagen, ABC) to optimal stable background antiretroviral therapy (SBG) to AIDS dementia complex (ADC) patients and address trial design

    A Randomized Trial of Convalescent Plasma in Covid-19 Severe Pneumonia

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    BACKGROUND:Convalescent plasma is frequently administered to patients with Covid-19 and hasbeen reported, largely on the basis of observational data, to improve clinical outcomes.Minimal data are available from adequately powered randomized, controlled trials. METHODS:We randomly assigned hospitalized adult patients with severe Covid-19 pneumoniain a 2:1 ratio to receive convalescent plasma or placebo. The primary outcome wasthe patient?s clinical status 30 days after the intervention, as measured on a six-pointordinal scale ranging from total recovery to death. RESULTS:A total of 228 patients were assigned to receive convalescent plasma and 105 toreceive placebo. The median time from the onset of symptoms to enrollment inthe trial was 8 days (interquartile range, 5 to 10), and hypoxemia was the mostfrequent severity criterion for enrollment. The infused convalescent plasma had amedian titer of 1:3200 of total SARS-CoV-2 antibodies (interquartile range, 1:800 to1:3200]. No patients were lost to follow-up. At day 30 day, no significant differencewas noted between the convalescent plasma group and the placebo group in thedistribution of clinical outcomes according to the ordinal scale (odds ratio, 0.83(95% confidence interval [CI], 0.52 to 1.35; P=0.46). Overall mortality was 10.96%in the convalescent plasma group and 11.43% in the placebo group, for a risk difference of −0.46 percentage points (95% CI, −7.8 to 6.8). Total SARS-CoV-2 antibodytiters tended to be higher in the convalescent plasma group at day 2 after the intervention. Adverse events and serious adverse events were similar in the two groups. CONCLUSIONS:no significant differences were observed in clinical status or overall mortality between patients treated with convalescent plasma and those who received placebo.(PlasmAr ClinicalTrials.gov number, NCT04383535.)Fil: Simonovich, Ventura A.. Hospital Italiano. Departamento de Medicina. Servicio de Clinica Medica.; ArgentinaFil: Burgos Pratx, Leandro D.. Hospital Italiano. Departamento de Medicina. Servicio de Clinica Medica.; ArgentinaFil: Scibona, Paula. Hospital Italiano. Departamento de Medicina. Servicio de Clinica Medica.; ArgentinaFil: Beruto, Maria Valeria. No especifíca;Fil: Vallone, Miguel Gabriel. No especifíca;Fil: Vázquez, C.. No especifíca;Fil: Savoy, N.. No especifíca;Fil: Giunta, Diego Hernan. No especifíca;Fil: Pérez, L.G.. No especifíca;Fil: Sánchez, M.L.. No especifíca;Fil: Gamarnik, Andrea Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Ojeda, D.S.. No especifíca;Fil: Santoro, D.M.. No especifíca;Fil: Camino, P. J.. No especifíca;Fil: Antelo, S.. No especifíca;Fil: Rainero, K.. No especifíca;Fil: Vidiella, G. P.. No especifíca;Fil: Miyazaki, E. A.. No especifíca;Fil: Cornistein, W.. No especifíca;Fil: Trabadelo, O. A.. No especifíca;Fil: Ross, F. M.. No especifíca;Fil: Spotti, M.. No especifíca;Fil: Funtowicz, G.. No especifíca;Fil: Scordo, W. E.. No especifíca;Fil: Losso, M. H.. No especifíca;Fil: Ferniot, I.. No especifíca;Fil: Pardo, P. E.. No especifíca;Fil: Rodriguez, E.. No especifíca;Fil: Rucci, P.. No especifíca;Fil: Pasquali, J.. No especifíca;Fil: Fuentes, N. A.. No especifíca;Fil: Esperatti, M.. No especifíca;Fil: Speroni, G. A.. No especifíca;Fil: Nannini, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Inmunología Clinica y Experimental de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Instituto de Inmunología Clinica y Experimental de Rosario; ArgentinaFil: Matteaccio, A.. No especifíca;Fil: Michelangelo, H.G.. No especifíca;Fil: Follmann, D.. No especifíca;Fil: Lane, H. Clifford. No especifíca;Fil: Belloso, Waldo Horacio. Hospital Italiano. Departamento de Medicina. Servicio de Clinica Medica.; Argentin
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