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1.
Wilderness Environ Med ; 34(1): 15-21, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36446725

RESUMO

INTRODUCTION: The purpose of this study was to investigate the psychometric properties of the remote first aid self-efficacy scale (RFA SES). The RFA SES is a 30-item self-report scale developed in response to emerging evidence showing that self-efficacy is predictive of performance. METHODS: Trained alumni from Wilderness Medical Associates (WMA) training courses and less trained students from Laurentian University (LU) were recruited via email to complete an online questionnaire at 2 different periods (T1 and T2). The questionnaire included demographic questions, the 30-item RFA SES, the 10-item Connor-Davidson resilience scale (CD-RISC), and the 10-item generalized self-efficacy scale (GSES). Data analysis included assessment of the dimensionality, reliability, and validity of the scale. RESULTS: There were 448 alumni from WMA and 1106 students from LU who participated in the study. The RFA SES demonstrated a clear unidimensional structure. The mean interitem correlation was 0.75 at T1. Test-retest reliability (T1 to T2) was high for both the LU group (intraclass correlation [ICC]=0.90) and the WMA group (ICC=0.92). Moderate correlations were found between RFA SES and CD-RISC (r=0.42, P<0.001), a general measure of resilience, and the GSES (r=0.48, P<0.001), a general measure of self-efficacy. Wilderness Medical Associates participants showed higher mean scores than LU students at T1 (t [569]=16.2, P<0.001). CONCLUSIONS: The RFA SES is a unidimensional, reliable, and potentially valid scale. Further research should focus on item reduction followed by additional tests of reliability and validity.


Assuntos
Socorristas , Resiliência Psicológica , Humanos , Autoeficácia , Primeiros Socorros , Reprodutibilidade dos Testes , Análise Fatorial , Inquéritos e Questionários
2.
Wilderness Environ Med ; 33(1): 75-91, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35120856

RESUMO

The Wilderness Medical Society convened a panel to review the literature and develop evidence-based clinical practice guidelines on the treatment of anaphylaxis, with an emphasis on a field-based perspective. The review also included literature regarding the definition, epidemiology, clinical manifestations, and prevention of anaphylaxis. The increasing prevalence of food allergies in the United States raises concern for a corresponding rise in the incidence of anaphylaxis. Intramuscular epinephrine is the primary treatment for anaphylaxis and should be administered before adjunctive treatments such as antihistamines, corticosteroids, and inhaled ß agonists. For outdoor schools and organizations, selecting a method to administer epinephrine in the field is based on considerations of cost, safety, and first responder training, as well as federal guidelines and state-specific laws.


Assuntos
Anafilaxia , Hipersensibilidade Alimentar , Anafilaxia/tratamento farmacológico , Anafilaxia/epidemiologia , Epinefrina/uso terapêutico , Hipersensibilidade Alimentar/tratamento farmacológico , Humanos , Sociedades Médicas , Estados Unidos , Meio Selvagem
3.
Bull World Health Organ ; 99(7): 514-528H, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34248224

RESUMO

OBJECTIVE: To assess the individual and community health effects of task shifting for emergency care in low-resource settings and underserved populations worldwide. METHODS: We systematically searched 13 databases and additional grey literature for studies published between 1984 and 2019. Eligible studies involved emergency care training for laypeople in underserved or low-resource populations, and any quantitative assessment of effects on the health of individuals or communities. We conducted duplicate assessments of study eligibility, data abstraction and quality. We synthesized findings in narrative and tabular format. FINDINGS: Of 19 308 papers retrieved, 34 studies met the inclusion criteria from low- and middle-income countries (21 studies) and underserved populations in high-income countries (13 studies). Targeted emergency conditions included trauma, burns, cardiac arrest, opioid poisoning, malaria, paediatric communicable diseases and malnutrition. Trainees included the general public, non-health-care professionals, volunteers and close contacts of at-risk populations, all trained through in-class, peer and multimodal education and public awareness campaigns. Important clinical and policy outcomes included improvements in community capacity to manage emergencies (14 studies), patient outcomes (13 studies) and community health (seven studies). While substantial effects were observed for programmes to address paediatric malaria, trauma and opioid poisoning, most studies reported modest effect sizes and two reported null results. Most studies were of weak (24 studies) or moderate quality (nine studies). CONCLUSION: First aid education and task shifting to laypeople for emergency care may reduce patient morbidity and mortality and build community capacity to manage health emergencies for a variety of emergency conditions in underserved and low-resource settings.


Assuntos
Atenção à Saúde , Serviços Médicos de Emergência , Tratamento de Emergência , Área Carente de Assistência Médica , Primeiros Socorros , Humanos
5.
Crop Prot ; 138: 105334, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33273751

RESUMO

In South Asia's rice-based cropping systems, most farmers flood and repetitively till their fields before transplanting. This establishment method, commonly termed puddled transplanted rice (TPR), is costly. In addition, it is labor and energy intensive. To increase labor and energy efficiency in rice production, reduced or zero-tilled direct seeded rice (ZT-DSR) is commonly proposed as an alternative tillage and crop establishment (TCE) option. Effective management of weeds in ZT-DSR however remains a major challenge. We conducted a four-year experiment under a rice-maize rotation in Northwestern Bangladesh in the eastern Gangetic Plains to examine the performance of two TCE methods and three weed management regimes (WMR) on the diversity and competitiveness of weed communities in the rice phase of the rotation. The Shannon-Weiner Diversity Index, a measure of species diversity, was significantly greater under ZT-DSR than puddled TPR. It was also greater under no weed control (Weedy) and two manual weeding (MW) treatments compared to chemical herbicide with manual weeding (C + MW). In DSR Weedy plots, weed communities began shifting from grasses to sedges from the rotation's second year, while in the ZT-DSR and C + MW treatments, sedges were consistently predominant. In both puddled TPR Weedy and TPR C + MW treatments, broadleaves and grasses were dominant in the initial year, while sedges dominated in the final year. There were significant main effects of year (Y) and weed management regime (WMR), but not of TCE. Significant Y × TCE and TCE × WMR interaction effects on rice yield were also observed. Grain yields under ZT-DSR were similar to puddled TPR. ZT-DSR with one application of pre-emergence herbicide followed by one hand weeding at 28 days after establishment however resulted in significantly higher grain yield (5.34 t ha-1) compared the other weed management regimes. Future research should address methods to effectively manage weed community composition shifts in both ZT-DSR and TPR under rice-maize rotations utilizing integrated and low-cost strategies that can be readily applied by farmers in the eastern Gangetic Plains.

6.
Front Pharmacol ; 11: 1005, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32733245

RESUMO

Selective activation of dopamine D1 receptors remains a promising pro-cognitive therapeutic strategy awaiting robust clinical investigation. PF-6142 is a key example from a recently disclosed novel series of non-catechol agonists and partial agonists of the dopamine D1/5 receptors (D1R) that exhibit pharmacokinetic (PK) properties suitable for oral delivery. Given their reported potential for functionally biased signaling compared to known catechol-based selective agonists, and the promising rodent PK profile of PF-6142, we utilized relevant in vivo assays in male rodents and male and female non-human primates (NHP) to evaluate the pharmacology of this new series. Studies in rodents showed that PF-6142 increased locomotor activity and prefrontal cortex acetylcholine release, increased time spent in wakefulness, and desynchronized the EEG, like known D1R agonists. D1R selectivity of PF-6142 was supported by lack of effect in D1R knock-out mice and blocked response in the presence of the D1R antagonist SCH-23390. Further, PF-6142 improved performance in rodent models of NMDA receptor antagonist-induced cognitive dysfunction, such as MK-801-disrupted paired-pulse facilitation, and ketamine-disrupted working memory performance in the radial arm maze. Similarly, PF-6142 reversed ketamine-induced deficits in NHP performing the spatial delayed recognition task. Of importance, PF-6142 did not alter the efficacy of risperidone in assays predictive of antipsychotic-like effect in rodents including pre-pulse inhibition and conditioned avoidance responding. These data support the continued development of non-catechol based D1R agonists for the treatment of cognitive impairment associated with brain disorders including schizophrenia.

7.
Glob Chang Biol ; 26(9): 4664-4678, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32531093

RESUMO

Climate change manifestation in the ocean, through warming, oxygen loss, increasing acidification, and changing particulate organic carbon flux (one metric of altered food supply), is projected to affect most deep-ocean ecosystems concomitantly with increasing direct human disturbance. Climate drivers will alter deep-sea biodiversity and associated ecosystem services, and may interact with disturbance from resource extraction activities or even climate geoengineering. We suggest that to ensure the effective management of increasing use of the deep ocean (e.g., for bottom fishing, oil and gas extraction, and deep-seabed mining), environmental management and developing regulations must consider climate change. Strategic planning, impact assessment and monitoring, spatial management, application of the precautionary approach, and full-cost accounting of extraction activities should embrace climate consciousness. Coupled climate and biological modeling approaches applied in the water and on the seafloor can help accomplish this goal. For example, Earth-System Model projections of climate-change parameters at the seafloor reveal heterogeneity in projected climate hazard and time of emergence (beyond natural variability) in regions targeted for deep-seabed mining. Models that combine climate-induced changes in ocean circulation with particle tracking predict altered transport of early life stages (larvae) under climate change. Habitat suitability models can help assess the consequences of altered larval dispersal, predict climate refugia, and identify vulnerable regions for multiple species under climate change. Engaging the deep observing community can support the necessary data provisioning to mainstream climate into the development of environmental management plans. To illustrate this approach, we focus on deep-seabed mining and the International Seabed Authority, whose mandates include regulation of all mineral-related activities in international waters and protecting the marine environment from the harmful effects of mining. However, achieving deep-ocean sustainability under the UN Sustainable Development Goals will require integration of climate consideration across all policy sectors.


Assuntos
Mudança Climática , Ecossistema , Biodiversidade , Humanos , Minerais , Mineração , Oceanos e Mares
8.
Proc Biol Sci ; 286(1911): 20191472, 2019 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-31551061

RESUMO

The distributions of migratory species in the ocean span local, national and international jurisdictions. Across these ecologically interconnected regions, migratory marine species interact with anthropogenic stressors throughout their lives. Migratory connectivity, the geographical linking of individuals and populations throughout their migratory cycles, influences how spatial and temporal dynamics of stressors affect migratory animals and scale up to influence population abundance, distribution and species persistence. Population declines of many migratory marine species have led to calls for connectivity knowledge, especially insights from animal tracking studies, to be more systematically and synthetically incorporated into decision-making. Inclusion of migratory connectivity in the design of conservation and management measures is critical to ensure they are appropriate for the level of risk associated with various degrees of connectivity. Three mechanisms exist to incorporate migratory connectivity into international marine policy which guides conservation implementation: site-selection criteria, network design criteria and policy recommendations. Here, we review the concept of migratory connectivity and its use in international policy, and describe the Migratory Connectivity in the Ocean system, a migratory connectivity evidence-base for the ocean. We propose that without such collaboration focused on migratory connectivity, efforts to effectively conserve these critical species across jurisdictions will have limited effect.


Assuntos
Migração Animal , Conservação dos Recursos Naturais , Política Ambiental , Animais , Ecossistema , Geografia , Oceanos e Mares
9.
Integr Zool ; 14(4): 396-409, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30983096

RESUMO

Rodents and weeds are important pests to rice crops in Southeast Asia. The interaction between these 2 major pests is poorly documented. In temperate cereal systems, seeds of grass weeds can be an important food source for rodents and weed cover along crop margins provides important refuge for rodents. In 2012 and 2013, a replicated study (n = 4) in Bago, Myanmar compared 4 treatments (rodents and weeds; no rodents and weeds; rodents and no weeds; no rodents and no weeds) each of 0.25 ha in transplanted rice. Weeds were managed with hand weeding in the wet season, and hand weeding and herbicides in the dry season. Plastic fences were installed to exclude rodents. We examined the weed cover and relative abundance of weed species, rodent damage, rodent population dynamics and rice yield loss caused by rodents and weeds. The dominant rodent species was Bandicota bengalensis. In the dry season, Cyperus difformis was dominant at the tillering stage and Echinochloa crus-galli was the dominant weed species at the booting stage. In the wet season E. crus-galli was a dominant weed throughout the season. Damage by rodents was higher in the dry season. There were larger economic benefits for best weed management and effective rodent control in the dry season (258 US$/ha) than in the wet season (30 US$/ha). Concurrent control of weeds in and around rice fields combined with coordinated community trapping of rodents during the early tillering stage and ripening stage of rice are recommended management options.


Assuntos
Agricultura , Ecossistema , Oryza , Plantas Daninhas , Roedores , Animais , Herbicidas , Dinâmica Populacional , Controle de Roedores
10.
J Neurosci Methods ; 308: 337-345, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30179705

RESUMO

BACKGROUND: The design and use of convection-enhanced delivery catheters remains an active field as clinical trials have highlighted suboptimal distribution as a contributory factor to the failure of those studies. Recent studies indicate limitations and challenges in achieving target coverage using conventional point source delivery. NEW METHOD: The recessed step catheter(RSC), developed by this group, does not function as a point source delivery device, but instead uses 'controlled reflux' of the infusate to a flow inhibiting recess feature. Here we investigate a range of clinically useful step lengths in agarose gel and investigate proof-of-principle in vivo(n = 5). Infusion morphology was characterised in terms of length, width and distribution volume over a range of flow rates. RESULTS: For a fixed infusion volume, increases in catheter step length strongly correlated with increases in the length and volume of distribution (r>0.90, p < 0.001) whilst there were small reductions in the width of distribution (r<-0.62, p < 0.001). Step lengths below 6 mm produced spherical distributions while steps above 12 mm produced elongated distributions. Increasing peak flow rates resulted in significant reductions in distribution volume at each step length, and an increased risk of reflux beyond the step. Modifications to the infusion morphology using changes in step length were confirmed in vivo. CONCLUSIONS: The combination of the recessed step and the ability to adjust the step length with this catheter design make it highly suitable for tailoring the distribution volume of the infusate to meet specific morphological target volumes in the brain.


Assuntos
Encéfalo/fisiologia , Sistemas de Liberação de Medicamentos/instrumentação , Sistemas de Liberação de Medicamentos/métodos , Animais , Cateterismo/instrumentação , Cateterismo/métodos , Catéteres , Convecção , Sus scrofa
11.
Prehosp Emerg Care ; 21(6): 673-681, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28657809

RESUMO

INTRODUCTION: A disparity exists between the skills needed to manage patients in wilderness EMS environments and the scopes of practice that are traditionally approved by state EMS regulators. In response, the National Association of EMS Physicians Wilderness EMS Committee led a project to define the educational core content supporting scopes of practice of wilderness EMS providers and the conditions when wilderness EMS providers should be required to have medical oversight. METHODS: Using a Delphi process, a group of experts in wilderness EMS, representing educators, medical directors, and regulators, developed model educational core content. This core content is a foundation for wilderness EMS provider scopes of practice and builds on both the National EMS Education Standards and the National EMS Scope of Practice Model. These experts also identified the conditions when oversight is needed for wilderness EMS providers. RESULTS: By consensus, this group of experts identified the educational core content for four unique levels of wilderness EMS providers: Wilderness Emergency Medical Responder (WEMR), Wilderness Emergency Medical Technician (WEMT), Wilderness Advanced Emergency Medical Technician (WAEMT), and Wilderness Paramedic (WParamedic). These levels include specialized skills and techniques pertinent to the operational environment. The skills and techniques increase in complexity with more advanced certification levels, and address the unique circumstances of providing care to patients in the wilderness environment. Furthermore, this group identified that providers having a defined duty to act should be functioning with medical oversight. CONCLUSION: This group of experts defined the educational core content supporting the specific scopes of practice that each certification level of wilderness EMS provider should have when providing patient care in the wilderness setting. Wilderness EMS providers are, indeed, providing health care and should thus function within defined scopes of practice and with physician medical director oversight.


Assuntos
Serviços Médicos de Emergência/métodos , Medicina de Emergência/educação , Meio Selvagem , Pessoal Técnico de Saúde/educação , Certificação , Técnica Delphi , Auxiliares de Emergência/educação , Humanos
12.
Pathog Dis ; 73(4)2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25673667

RESUMO

Escherichia coli is the leading cause of urinary tract infections (UTIs), one of the most common infections in humans. P fimbria was arguably the first proposed virulence factor for uropathogenic E. coli, based on the capacity of E. coli isolated from UTIs to adhere to exfoliated epithelial cells in higher numbers than fecal strains of E. coli. Overwhelming epidemiologic evidence has been presented for involvement of P fimbriae in colonization. It has been difficult, however, to demonstrate this requirement for uropathogenic strains in animal models of infections or in humans. In this study, a signature-tagged mutagenesis screen identified a P-fimbrial gene (papC) and 18 other genes as being among those required for full fitness of cystitis isolate E. coli F11. A P-fimbrial mutant was outcompeted by the wild-type strain in cochallenge in the murine model of ascending UTI, and this colonization defect could be complemented with the cloned pap operon. To our knowledge, this study is the first to fulfill molecular Koch's postulates in which a pathogenic strain was attenuated by mutation of pap genes and then complemented to restore fitness, confirming P fimbria as a virulence factor in a pathogenic clinical isolate.


Assuntos
Adesinas Bacterianas/metabolismo , Aderência Bacteriana , Infecções por Escherichia coli/microbiologia , Fímbrias Bacterianas/metabolismo , Infecções Urinárias/microbiologia , Escherichia coli Uropatogênica/fisiologia , Fatores de Virulência/metabolismo , Adesinas Bacterianas/genética , Animais , Coinfecção/microbiologia , Modelos Animais de Doenças , Fímbrias Bacterianas/genética , Deleção de Genes , Teste de Complementação Genética , Testes Genéticos , Camundongos , Mutagênese , Óperon , Escherichia coli Uropatogênica/genética , Fatores de Virulência/genética
13.
Wilderness Environ Med ; 25(4 Suppl): S15-8, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25498258

RESUMO

The Epinephrine Roundtable took place on July 27, 2008, during the 25th Annual Meeting of the Wilderness Medical Society (WMS) in Snowmass, CO. The WMS convened this roundtable to explore areas of consensus and uncertainty in the field treatment of anaphylaxis. Panelists were selected on the basis of their relevant academic or professional experience. There is a paucity of data that address the treatment of anaphylaxis in the wilderness. Anaphylaxis is a rare disease, with a sudden onset and drastic course that does not lend itself to study in randomized, controlled trials. Therefore, the panel endorsed the following position based on the limited available evidence and review of published articles, as well as expert consensus. The position represents the consensus of the panelists and is endorsed by the WMS. In 2014, the authors reviewed relevant articles published since the Epinephrine Roundtable. The following is an updated version of the original guidelines published in Wilderness & Environmental Medicine 2010;21(4):185-187.


Assuntos
Anafilaxia/tratamento farmacológico , Broncodilatadores/administração & dosagem , Epinefrina/administração & dosagem , Padrões de Prática Médica , Medicina Selvagem , Broncodilatadores/efeitos adversos , Competência Clínica , Epinefrina/efeitos adversos , Humanos , Sociedades Médicas , Medicina Selvagem/educação , Medicina Selvagem/normas
14.
AoB Plants ; 62014 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-25336336

RESUMO

Crop productivity is largely affected by abiotic factors such as flooding and by biotic factors such as weeds. Although flooding after direct seeding of rice helps suppress weeds, it also can adversely affects germination and growth of rice, resulting in poor crop establishment. Barnyard grasses (Echinochloa spp.) are among the most widespread weeds affecting rice, especially under direct seeding. The present work aimed to establish effective management options to control these weeds. We assessed the effects of variable depths and time of submergence on germination, seedling growth and carbohydrate metabolism of (i) two cultivars of rice known to differ in their tolerance to flooding during germination and (ii) two barnyard grasses (Echinochloa colona and E. crus-galli) that commonly infest rice fields. Flooding barnyard grasses with 100-mm-deep water immediately after seeding was effective in suppressing germination and growth. Echinochloa colona showed greater reductions in emergence, shoot and root growth than E. crus-galli. Delaying flooding for 2 or 4 days was less injurious to both species. Echinochloa colona was also more susceptible to flooding than the flood-sensitive rice cultivar 'IR42'. The activity of alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) in rice seedlings was increased by flooding after sowing but with greater increases in 'Khao Hlan On' compared with 'IR42'. The activity of ADH and PDC was enhanced to a similar extent in both barnyard grasses. Under aerobic conditions, the activity of ADH and PDC in the two barnyard grasses was downregulated, which might contribute to their inherently faster growth compared with rice. Aldehyde dehydrogenase activity was significantly enhanced in flood-tolerant 'Khao Hlan On' and E. crus-galli, but did not increase in flood-sensitive E. colona and 'IR42', implying a greater ability of the flood-tolerant types to detoxify acetaldehyde generated during anaerobic fermentation. Confirmation of this hypothesis is now being sought.

16.
Neuropharmacology ; 82: 41-8, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24647121

RESUMO

Kynurenic acid (KYNA) is a tryptophan metabolite that acts in the brain as an endogenous antagonist at multiple receptors, including glutamate and α7 nicotinic acetylcholine receptors. Increased levels of KYNA have been demonstrated in the brain of patients with a range of neurocognitive disorders, including schizophrenia, and are hypothesized to contribute to cognitive symptoms. Reducing KYNA levels by administering inhibitors of enzymes of the kynurenine pathway, particularly kynurenine aminotransferase II (KAT II), has been proposed as a treatment for such cognitive impairments. Here we report that administration of a systemically available KAT II inhibitor, PF-04859989, restores glutamate release events ("transients") evoked by pressure ejections of nicotine into the prefrontal cortex of rats exhibiting elevated KYNA levels. Nicotine-evoked glutamatergic transients can be reliably evoked and recorded after repeated pressure ejections of nicotine over 4-5 h. Systemic administration of l-kynurenine (100 mg/kg; i.p.) significantly increased frontal cortical KYNA levels and greatly attenuated the amplitude of nicotine-evoked glutamatergic transients. Systemic administration of PF-04859989 30 min prior to administration of l-kynurenine, but not when administered 30 min after l-kynurenine, restored glutamatergic transients recorded up to 75 min after the administration of the KAT II inhibitor. Furthermore, the KAT II inhibitor significantly reversed l-kynurenine-induced elevations of brain KYNA levels. The KAT II inhibitor did not affect nicotine-evoked glutamatergic transients in rats not pre-treated with l-kynurenine. Because PF-04859989 restores evoked glutamate signaling it therefore is a promising therapeutic compound for benefiting the cognitive symptoms of schizophrenia and other disorders associated with elevated brain KYNA levels.


Assuntos
Inibidores Enzimáticos/farmacologia , Ácido Glutâmico/metabolismo , Nicotina/farmacologia , Agonistas Nicotínicos/farmacologia , Córtex Pré-Frontal/efeitos dos fármacos , Pirazóis/farmacologia , Animais , Fármacos do Sistema Nervoso Central/farmacologia , Ácido Cinurênico/metabolismo , Cinurenina/farmacologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Microdiálise , Microeletrodos , Cloreto de Potássio/farmacologia , Córtex Pré-Frontal/fisiologia , Ratos Sprague-Dawley , Ratos Wistar , Transaminases/antagonistas & inibidores , Transaminases/metabolismo
18.
IEEE Trans Haptics ; 6(4): 453-63, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24808397

RESUMO

Many of the devices used in haptics research are over-engineered for the task and are designed with capabilities that go far beyond human perception levels. Designing devices that more closely match the limits of human perception will make them smaller, less expensive, and more useful. However, many device-centric perception thresholds have yet to be evaluated. To this end, three experiments were conducted, using one degree-of-freedom contact location feedback device in combination with a kinesthetic display, to provide a more explicit set of specifications for similar tactile-kinesthetic haptic devices. The first of these experiments evaluated the ability of humans to repeatedly localize tactile cues across the fingerpad. Subjects could localize cues to within 1.3 mm and showed bias toward the center of the fingerpad. The second experiment evaluated the minimum perceptible difference of backlash at the tactile element. Subjects were able to discriminate device backlash in excess of 0.46 mm on low-curvature models and 0.93 mm on high-curvature models. The last experiment evaluated the minimum perceptible difference of system delay between user action and device reaction. Subjects were able to discriminate delays in excess of 61 ms. The results from these studies can serve as the maximum (i.e., most demanding) device specifications for most tactile-kinesthetic haptic systems.


Assuntos
Cinestesia/fisiologia , Tato/fisiologia , Adulto , Sinais (Psicologia) , Feminino , Dedos/inervação , Dedos/fisiologia , Humanos , Masculino , Fenômenos Mecânicos , Percepção/fisiologia , Psicofísica/métodos , Interface Usuário-Computador
20.
AoB Plants ; 2012: pls019, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22957137

RESUMO

BACKGROUND AND AIMS: Direct seeding of rice is being adopted in rainfed and irrigated lowland ecosystems because it reduces labour costs in addition to other benefits. However, early flooding due to uneven fields or rainfall slows down seed germination and hinders crop establishment. Conversely, early flooding helps suppress weeds and reduces the costs of manual weeding and/or dependence on herbicides; however, numerous weed species are adapted to lowlands and present challenges for the use of flooding to control weeds. Advancing knowledge on the mechanisms of tolerance of flooding during germination and early growth in rice and weeds could facilitate the development of improved rice varieties and effective weed management practices for direct-seeded rice. PRINCIPAL RESULTS: Rice genotypes with a greater ability to germinate and establish in flooded soils were identified, providing opportunities to develop varieties suitable for direct seeding in flooded soils. Tolerance of flooding in these genotypes was mostly attributed to traits associated with better ability to mobilize stored carbohydrates and anaerobic metabolism. Limited studies were undertaken in weeds associated with lowland rice systems. Remaining studies compared rice and weeds and related weed species such as Echinochloa crus-galli and E. colona or compared ecotypes of the same species of Cyperus rotundus adapted to either aerobic or flooded soils. CONCLUSIONS: Tolerant weeds and rice genotypes mostly developed similar adaptive traits that allow them to establish in flooded fields, including the ability to germinate and elongate faster under hypoxia, mobilize stored starch reserves and generate energy through fermentation pathways. Remarkably, some weeds developed additional traits such as larger storage tubers that enlarge further in deeper flooded soils (C. rotundus). Unravelling the mechanisms involved in adaptation to flooding will help design management options that will allow tolerant rice genotypes to adequately establish in flooded soils while simultaneously suppressing weeds.

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