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1.
Front Microbiol ; 14: 1249884, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37928683

RESUMO

Recent efforts have been made to review the state of the art on a variety of questions and targets in paleoparasitology, including protozoan taxa. Meanwhile, these efforts seemed to let aside Cryptosporidium, and we then intended to review its paleoparasitological record to assess its past distribution and favored detection methods, and eventually highlight needed research trajectories. This review shows that contrary to other parasites, most of the positive results came from South-American sites and coprolites rather than sediment samples, highlighting the need to test this kind of material, notably in Europe where many negative results were reported in the published literature from sediment samples. Moreover, aDNA-based detections are nearly absent from the paleoparasitological record of this parasite, though punctually shown successful. With their potential to address the evolutionary history of Cryptosporidium species, notably through their 18S rRNA tree, aDNA-based approaches should be encouraged in the future. In sum, and though the limits of currently used methods and materials remain unclear, this review highlights the potential role of coprolites and aDNA for the study of Cryptosporidium species in the past and how this history shaped their current diversity and distribution, notably among human populations but also farm animals.

2.
Cochrane Database Syst Rev ; 9: MR000065, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-37655964

RESUMO

BACKGROUND: The World Health Organization declared the COVID-19 pandemic on 11 March 2020. Vaccine development and deployment were swiftly prioritised as a method to manage and control disease spread. The development of an effective vaccine relies on people's participation in randomised trials. Recruitment to vaccine trials is particularly challenging as it involves healthy volunteers who may have concerns around the potential risks and benefits associated with rapidly developed vaccines. OBJECTIVES: To explore the factors that influence a person's decision to participate in a vaccine trial in the context of a pandemic or epidemic. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was June 2021. SELECTION CRITERIA: We included qualitative studies and mixed-methods studies with an identifiable qualitative component. We included studies that explored the perspectives of adults aged 18 years or older who were invited to take part in vaccine trials in the context of a pandemic or epidemic. DATA COLLECTION AND ANALYSIS: We assessed the title, abstracts and full texts identified by the search. We used a sampling frame to identify data-rich studies that represented a range of diseases and geographical spread. We used QSR NVivo to manage extracted data. We assessed methodological limitations using an adapted version of the Critical Skills Appraisal Programme (CASP) tool for qualitative studies. We used the 'best-fit framework approach' to analyse and synthesise the evidence from our included studies. We then used the Confidence in the Evidence from Reviews of Qualitative research (GRADE-CERQual) assessment to assess our confidence in each finding and develop implications for practice. MAIN RESULTS: We included 34 studies in our review. Most studies related to HIV vaccine trials. The other studies related to Ebola virus, tuberculosis, Zika virus and COVID-19. We developed 20 key findings, under three broad themes (with seven subthemes), that described the factors that people consider when deciding whether to take part in a vaccine trial for a pandemic or epidemic disease. Our GRADE-CERQual confidence was high in nine of the key findings, moderate in 10 key findings and low in one key finding. The main reason for downgrading review findings were concerns regarding the relevance and adequacy of the underlying data. As a result of the over-representation of HIV studies, our GRADE-CERQual assessment of some findings was downgraded in terms of relevance because the views described may not reflect those of people regarding vaccine trials for other pandemic or epidemic diseases. Adequacy relates to the degree of richness and quantity of data supporting a review finding. Moderate concerns about adequacy resulted in a downgrading of some review findings. Some factors were considered to be under the control of the trial team. These included how trial information was communicated and the inclusion of people in the community to help with trial information dissemination. Aspects of trial design were also considered under control of the trial team and included convenience of participation, provision of financial incentives and access to additional support services for those taking part in the trial. Other factors influencing people's decision to take part could be personal, from family, friends or wider society. From a personal perceptive, people had concerns about vaccine side effects, vaccine efficacy and possible impact on their daily lives (carer responsibilities, work, etc.). People were also influenced by their families, and the impact participation may have on relationships. The fear of stigma from society influenced the decision to take part. Also, from a societal perspective, the level of trust in governments' involvement in research and trial may influence a person's decision. Finally, the perceived rewards, both personal and societal, were influencing factors on the decision to participate. Personal rewards included access to a vaccine, improved health and improved disease knowledge, and a return to normality in the context of a pandemic or epidemic. Potential societal rewards included helping the community and contributing to science, often motivated by the memories of family and friends who had died from the disease. AUTHORS' CONCLUSIONS: This review identifies many of the factors that influence a person's decision to take part in a vaccine trial, and these reflect findings from reviews that examine trials more broadly. However, we also recognise some factors that become more important in connection with a vaccine trial in the context of a pandemic or epidemic. These factors include the potential stigma of taking part, the possible adverse effects of a vaccine, the added motivation for helping society, the role of community leaders in trial dissemination, and the level of trust placed in governments and companies developing vaccines. These specific influences need to be considered by trial teams when designing, and communicating about, vaccine trials in the context of a pandemic or epidemic.


Assuntos
COVID-19 , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Infecção por Zika virus , Zika virus , Adulto , Humanos , Medo , Amigos , Pandemias
3.
Water Res ; 226: 119206, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36244141

RESUMO

The fate and transport of nanoparticles (NPs) in streams is critical for understanding their overall environmental impact. Using a unique field-scale stream at the Notre Dame-Linked Experimental Ecosystem Facility, we investigated the impact of biofilms and the presence of dissolved organic matter (DOM) on the transport of titanium dioxide (TiO2) NPs. Experimental breakthrough curves were analyzed using temporal moments and fit using a mobile-immobile model. The presence of biofilms in the stream severely reduced the transport of the TiO2 NPs, but this was mitigated by the presence of DOM. Under minimal biofilm conditions, the presence of DOM increased the mass recovery of TiO2 from 4.2% to 32% for samples taken 50 m downstream. For thriving biofilm conditions only 0.5% of the TiO2 mass was recovered (50 m), but the presence of DOM improved the mass recovery TiO2 to 36%. The model was suitable for predicting early, peak, tail, and truncation time portions of the breakthrough curves, which attests to its ability to capture a range of processes in the mobile and immobile domains of the stream. The model outcomes supported the hypothesis that DOM changed the interaction of NP-biofilm from an irreversible to a reversible process. Collectively, these outcomes stress the importance of considering biogeological complexity when predicting the transport of NPs in streams.


Assuntos
Matéria Orgânica Dissolvida , Nanopartículas , Ecossistema , Titânio , Biofilmes
4.
Pilot Feasibility Stud ; 8(1): 225, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36195963

RESUMO

BACKGROUND: While international guidelines recommend medication reviews as part of the management of multimorbidity, evidence on how to implement reviews in practice in primary care is lacking. The MyComrade (MultimorbiditY Collaborative Medication Review And Decision Making) intervention is an evidence-based, theoretically informed novel intervention which aims to support the conduct of medication reviews for patients with multimorbidity in primary care. AIM: The pilot study aimed to assess the feasibility of a definitive trial of the MyComrade intervention across two healthcare systems (Republic of Ireland (ROI) and Northern Ireland (NI)). DESIGN: A pilot cluster-randomised controlled trial was conducted (clustered at general practice level), using specific progression criteria and a process evaluation framework. SETTING: General practices in the ROI and NI. PARTICIPANTS: Eligible practices were those in defined geographical areas who had GP's and Practice Based Pharmacists (PBP's) (in NI) willing to conduct medication reviews. Eligible patients were those aged 18 years and over, with multi morbidity and on ten or more medications. INTERVENTION: The MyComrade intervention is an evidence-based, theoretically informed novel intervention which aims to support the conduct of medication reviews for patients with multimorbidity in primary care, using a planned collaborative approach guided by an agreed checklist, within a specified timeframe. OUTCOME MEASURES: Feasibility outcomes, using pre-determined progression criteria, assessed practice and patient recruitment and retention and intervention acceptability and fidelity. Anonymised patient-related quantitative data, from practice medical records and patient questionnaires were collected at baseline, 4 and 8 months, to inform potential outcome measures for a definitive trial. These included (i) practice outcomes-completion of medication reviews; (ii) patient outcomes-treatment burden and quality of life; (iii) prescribing outcomes-number and changes of prescribed medications and incidents of potentially inappropriate prescribing; and (iv) economic cost analysis. The framework Decision-making after Pilot and feasibility Trials (ADePT) in conjunction with a priori progression criteria and process evaluation was used to guide the collection and analysis of quantitative and qualitative data. RESULTS: The recruitment of practices (n = 15) and patients (n = 121, mean age 73 years and 51% female), representing 94% and 38% of a priori targets respectively, was more complex and took longer than anticipated; impacted by the global COVID-19 pandemic. Retention rates of 100% of practices and 85% of patients were achieved. Both practice staff and patients found the intervention acceptable and reported strong fidelity to the My Comrade intervention components. Some practice staff highlighted concerns such as poor communication of the reviews to patients, dissatisfaction regarding incentivisation and in ROI the sustainability of two GPs collaboratively conducting the medication reviews. Assessing outcomes from the collected data was found feasible and appropriate for a definitive trial. Two progression criteria met the 'Go' criterion (practice and patient retention), two met the 'Amend' criterion (practice recruitment and intervention implementation) and one indicated a 'Stop - unless changes possible' (patient recruitment). CONCLUSION: The MyComrade intervention was found to be feasible to conduct within two different healthcare systems. Recruitment of participants requires significant time and effort given the nature of this population and the pairing of GP and pharmacist may be more sustainable to implement in routine practice. TRIAL REGISTRATION: Registry: ISRCTN, ISRCTN80017020 ; date of confirmation 4/11/2019; retrospectively registered.

5.
Eur J Cancer Care (Engl) ; 31(6): e13733, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36259243

RESUMO

Oral anti-cancer medications (OAMs) are increasingly prescribed in oncology, and although administered at home, ongoing monitoring generally requires the patient to attend an acute hospital. With the requirement to provide safe yet convenient care and to increase hospital capacity, the potential exists to transition this cohort of patients to the community to be assessed by oncology health care professionals (HCPs). The onset of COVID-19 facilitated this planned transition. OBJECTIVE: The primary objective was to understand stakeholders' perceptions of a community-based advanced nurse practitioner (ANP)-led integrated OAM care model for adults. METHODS: Qualitative data from interviews and focus groups were obtained from 33 individuals; either service users who attended ANP-led OAM clinics or stakeholders involved in OAM care. Data were subsequently analysed using thematic analysis. RESULTS: Four themes were identified and included reflection on pre-COVID-19 system, role of ANP in current OAM care, importance of robust communication and infrastructural requirements for transition to an integrated OAM care model. CONCLUSION: This study demonstrated that patients and HCPs perceived the proposal positively. They identified the ANP as the appropriate HCP to care for this cohort and the importance of communication and strategic planning for transitioning this model of care to the community setting. CLINICAL TRIAL REGISTRATION: ISRCTN10401455.


Assuntos
Tratamento Farmacológico da COVID-19 , Neoplasias Bucais , Profissionais de Enfermagem , Adulto , Humanos , Pesquisa Qualitativa
6.
BMC Prim Care ; 23(1): 86, 2022 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-35436863

RESUMO

OBJECTIVE: Inappropriate use of antibiotics has been acknowledged as a significant contributor to the proliferation of antimicrobial resistance worldwide. Physician prescribing of antibiotics has been identified as a factor in the inappropriate use of antibiotics. One methodology that is used in an attempt to alter physician prescribing behaviours is audit and feedback. This study aimed to explore the perceptions of Irish General Practitioners (GPs) towards the national introduction of postal feedback on their antibiotic prescribing behaviours beginning in 2019. DESIGN: A qualitative descriptive methodology was used. Semi-structured interviews were conducted with GPs in receipt of postal audit and feedback. METHOD: GPs working in Ireland and in receipt of postal audit and feedback on their antibiotic prescribing behaviours participated in phone-based interviews. The interviews were recorded and transcribed verbatim. The collected data was then analysed using an inductive thematic analysis. RESULTS: Twelve GPs participated in the study (female = 5). Three themes were identified from the analysis. The themes identified were the reliability and validity of the feedback received, feedback on antibiotic prescribing is useful but limited and feedback needs to be easily digestible. CONCLUSION: While the postal audit and feedback were broadly welcomed by the participants, the themes identified a perceived limitation in the quality of the feedback data, the perception of a likely low public health impact of the feedback and difficulties with efficiently processing the audit and feedback information. These findings can help refine future audit and feedback interventions on antibiotic prescribing.


Assuntos
Anti-Infecciosos , Clínicos Gerais , Antibacterianos/uso terapêutico , Retroalimentação , Feminino , Humanos , Reprodutibilidade dos Testes
7.
Sci Total Environ ; 829: 154419, 2022 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-35276172

RESUMO

Inland lakes face unprecedented pressures from climatic and anthropogenic stresses, causing their recession and desiccation globally. Climate change is increasingly blamed for such environmental degradation, but in many regions, direct anthropogenic pressures compound, and sometimes supersede, climatic factors. This study examined a human-environmental system - the terminal Hamun Lakes on the Iran-Afghanistan border - that embodies amplified challenges of inland waters. Satellite and climatic data from 1984 to 2019 were fused, which documented that the Hamun Lakes lost 89% of their surface area between 1999 and 2001 (3809 km2 versus 410 km2), coincident with a basin-wide, multi-year meteorological drought. The lakes continued to shrink afterwards and desiccated in 2012, despite the above-average precipitation in the upstream basin. Rapid growth in irrigated agricultural lands occurred in upstream Afghanistan in the recent decade, consuming water that otherwise would have fed the Hamun Lakes. Compounding upstream anthropogenic stressors, Iran began storing flood water that would have otherwise drained to the lakes, for urban and agricultural consumption in 2009. Results from a deep Learning model of Hamun Lakes' dynamics indicate that the average lakes' surface area from 2010 to 2019 would have been 2.5 times larger without increasing anthropogenic stresses across the basin. The Hamun Lakes' desiccation had major socio-environmental consequences, including loss of livelihood, out-migration, dust-storms, and loss of important species in the region.


Assuntos
Efeitos Antropogênicos , Lagos , Agricultura , Mudança Climática , Monitoramento Ambiental , Humanos , Água
8.
Diabet Med ; 38(4): e14468, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33230846

RESUMO

AIMS: To identify all extant instruments used to measure diabetes distress in adults with Type 1 diabetes and to evaluate the evidence for the measurement properties of these instruments. METHODS: Medline, Embase, CINAHL plus and PsycINFO were systematically searched from inception up until 12 March 2020 for all publications which evaluated the psychometric properties of diabetes distress measurement instruments. The quality of the methodology and the measurement properties in the identified studies were evaluated using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines. RESULTS: Seven out of the 7656 articles retrieved in the search were included in the final review. Four diabetes distress measurement instruments were identified, none of which displayed evidence for all measurement properties specified in the COSMIN guidelines. The Problem Areas in Diabetes-11 (PAID-11) demonstrated the best psychometric properties, displaying strong evidence for structural validity, internal consistency, hypothesis testing, responsiveness and criterion validity. The Problem Areas in Diabetes scale (PAID) was the most frequently investigated instrument, demonstrating good relevance and hypothesis testing across four studies; however, concerns remain over its factor structure. CONCLUSION: The PAID-11 appears to be the most psychometrically sound instrument for measuring diabetes distress in adults with Type 1 diabetes, displaying strong evidence for a range of measurement properties. However, as only one study evaluated this instrument and its content validity has yet to be assessed, further validation is warranted. Additional qualitative work is needed to assess the content validity of these instruments among individuals with Type 1 diabetes.


Assuntos
Lista de Checagem/métodos , Diabetes Mellitus Tipo 1/psicologia , Psicometria/métodos , Estresse Psicológico/diagnóstico , Adulto , Lista de Checagem/normas , Consenso , Diabetes Mellitus Tipo 1/diagnóstico , Nível de Saúde , Humanos , Guias de Prática Clínica como Assunto , Angústia Psicológica , Psicometria/normas , Reprodutibilidade dos Testes
9.
Proc Natl Acad Sci U S A ; 117(4): 1935-1940, 2020 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-31932433

RESUMO

A growing empirical literature associates climate anomalies with increased risk of violent conflict. This association has been portrayed as a bellwether of future societal instability as the frequency and intensity of extreme weather events are predicted to increase. This paper investigates the theoretical foundation of this claim. A seminal microeconomic model of opportunity costs-a mechanism often thought to drive climate-conflict relationships-is extended by considering realistic changes in the distribution of climate-dependent agricultural income. Results advise caution in using empirical associations between short-run climate anomalies and conflicts to predict the effect of sustained shifts in climate regimes: Although war occurs in bad years, conflict may decrease if agents expect more frequent bad years. Theory suggests a nonmonotonic relation between climate variability and conflict that emerges as agents adapt and adjust their behavior to the new income distribution. We identify 3 measurable statistics of the income distribution that are each unambiguously associated with conflict likelihood. Jointly, these statistics offer a unique signature to distinguish opportunity costs from competing mechanisms that may relate climate anomalies to conflict.


Assuntos
Conflitos Armados/economia , Mudança Climática , Produtos Agrícolas/crescimento & desenvolvimento , Desenvolvimento Econômico/estatística & dados numéricos , Modelos Teóricos , Violência/economia , Humanos , Fatores de Risco , Abastecimento de Água/estatística & dados numéricos
10.
Biol Trace Elem Res ; 191(1): 214-223, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30600496

RESUMO

In this study, we assessed concentrations of 13 trace metals in the scales of Notothenia coriiceps, Trematomus bernacchii and Gobionotothen gibberifrons caught off the coast of James Ross Island (Antarctic Peninsula). Overall, our results for scales broadly match those of previous studies using different fish and different organs, with most metals found at trace levels and manganese, aluminium, iron and zinc occurring at high levels in all species. This suggests that scales can serve as a useful, non-invasive bioindicator of long-term contamination in Antarctic fishes. High accumulation of manganese, aluminium, iron and zinc is largely due to high levels in sediments associated with nearby active volcanic sites. Manganese, vanadium and aluminium showed significant positive bioaccumulation in T. bernacchii (along with non-significant positive accumulation of iron, zinc, cobalt and chromium), most likely due to greater dietary specialisation on sediment feeding benthic prey and higher trophic species. Levels of significance in bioaccumulation regressions were strongly affected by large-scale variation in the data, driven largely by individual differences in diet and/or changes in habitat use and sex differences associated with life stage and reproductive status. Increased levels of both airborne deposition and precipitation and meltwater runoff associated with climate change may be further adding to the already high levels of manganese, aluminium, iron and zinc in Antarctic Peninsula sediments. Further long-term studies are encouraged to elucidate mechanisms of uptake (especially for aluminium and iron) and possible intra- and interspecific impacts of climate change on the delicate Antarctic food web.


Assuntos
Peixes/metabolismo , Cadeia Alimentar , Oligoelementos/metabolismo , Animais , Regiões Antárticas
11.
Korean J Parasitol ; 57(6): 587-593, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31914509

RESUMO

Excavation (2008-2014) carried out under the Uffizi Gallery (Florence, Italy) led to the discovery of 75 individuals, mostly buried in multiple graves. Based on Roman minted coins, the graves were preliminarily dated between the second half of the 4th and the beginning of the 5th centuries CE. Taphonomy showed that this was an emergency burial site associated with a catastrophic event, possibly an epidemic of unknown etiology with high mortality rates. In this perspective, paleoparasitological investigations were performed on 18 individuals exhumed from 9 multiple graves to assess the burden of gastrointestinal parasitism. Five out of eighteen individuals (27.7%) tested positive for ascarid-type remains; these are considered as "decorticated" Ascaris eggs, which have lost their outer mammillated coat. Roundworms (genus Ascaris) commonly infest human populations under dire sanitary conditions. Archaeological and historical evidence indicates that Florentia suffered a period of economic crisis between the end of 4th and the beginning of the 5th centuries CE, and that the aqueduct was severely damaged at the beginning of the 4th century CE, possibly during the siege of the Goths (406 CE). It is more than plausible that the epidemic, possibly coupled with the disruption of the aqueduct, deeply affected the living conditions of these individuals. A 27.7% frequency suggests that ascariasis was widespread in this population. This investigation exemplifies how paleoparasitological information can be retrieved from the analysis of sediments sampled in cemeteries, thus allowing a better assessment of the varying frequency of parasitic infections among ancient populations.


Assuntos
Ascaris/isolamento & purificação , Enteropatias Parasitárias/história , Enteropatias Parasitárias/parasitologia , Animais , Arqueologia/história , Ascaris/citologia , Cemitérios/história , História Antiga , Humanos , Itália , Óvulo/citologia , Parasitologia/história
12.
Sci Rep ; 7(1): 14287, 2017 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-29079758

RESUMO

Bioturbation refers to the transport processes carried out by living organisms and their physical effects on soils and sediments. It is widely recognized as an important mixing mechanism, particularly at the sediment-water interface in many natural systems. In order to quantify its impact on mixing, we propose a process-based model based on simple assumptions about organism burrowing behavior. Specifically, we consider burrowing events to be stochastic but memoryless, leading to exponential inter-burrow waiting times and depths. We then explore the impact of two different transport mechanisms on the vertical concentration distributions predicted by the model for a conservative (inert) tracer. We compare the results of our model to experimental data from a recent laboratory study of bioturbation by the freshwater oligochaete worm Lumbriculus variegatus, and find good quantitative agreement.

13.
Front Psychol ; 8: 1073, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28701984

RESUMO

Most studies of human-tool interactions focus on the typical use of a tool (e.g., cutting in the case of a knife). However, little is known about situations requiring atypical tool use (e.g., using a knife to tighten a screw). The present study focused on a selection of atypical uses of everyday tools which might be in conflict with their typical use. Our objective was to study how tool function influences the selection of the relevant action. In Experiment 1, which involved visuomotor priming, two everyday tools (a knife and a screwdriver) and two neutral tools (two bars, with no strong functional affordance) were used as primes and targets. Participants had to use the target with the appropriate box (indicated by the color) that allowed to make an action. Longer initiation times were observed when the prime was an everyday tool, irrespective of the nature of the target. We therefore observed a conflict between functional and situational affordances. To investigate whether the priming effect is caused by the task-irrelevance of the prime, we asked the participants in Experiment 2 to perform an action associated with the prime. The results showed longer initiation times only when the prime and target were everyday tools, irrespective of their precise nature. This suggests that activation of the typical use of a tool might not be fully automatic but flexible depending on the situation.

14.
J Mater Chem B ; 5(30): 6027-6033, 2017 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32264359

RESUMO

Hydroxyapatite and fluorhydroxyapatite (F)HA nanoparticles were synthesised in the presence of branched poly(acrylic acid)s (PAA) synthesised via reversible addition-fragmentation chain transfer polymerisation and compared to those synthesised in the presence of linear PAA. Analysis of the resulting nanoparticles using Fourier transform infrared spectroscopy, powder X-ray diffraction and transition electron microscopy found that the polymer was included within the nanoparticle samples and affected their morphology with nanoparticles synthesised in the presence of branched PAA being more acicular and smaller overall.

15.
Environ Sci Technol ; 50(18): 10047-54, 2016 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-27529186

RESUMO

Bioturbation is the dominant mode of sediment transport in many aquatic environments and strongly influences both sediment biogeochemistry and contaminant fate. Available bioturbation models rely on highly simplified biodiffusion formulations that inadequately capture the behavior of many benthic organisms. We present a novel experimental and modeling approach that uses time-lapse imagery to directly relate burrow formation to resulting sediment mixing. We paired white-light imaging of burrow formation with fluorescence imaging of tracer particle redistribution by the oligochaete Lumbriculus variegatus. We used the observed burrow formation statistics and organism density to parametrize a parsimonious model for sediment mixing based on fundamental random walk theory. Worms burrowed over a range of times and depths, resulting in homogenization of sediments near the sediment-water interface, rapid nonlocal transport of tracer particles to deep sediments, and large areas of unperturbed sediments. Our fundamental, parsimonious random walk model captures the central features of this highly heterogeneous sediment bioturbation, including evolution of the sediment-water interface coupled with rapid near-surface mixing and anomalous late-time mixing resulting from infrequent, deep burrowing events. This approach provides a general, transferable framework for explicitly linking sediment transport to governing biophysical processes.


Assuntos
Sedimentos Geológicos/química , Oligoquetos , Animais , Comportamento Animal , Modelos Teóricos , Movimento , Água , Poluentes Químicos da Água
16.
J Vis Exp ; (105)2015 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-26651065

RESUMO

Advective exchange between the pore space of sediments and the overlying water column, called hyporheic exchange in fluvial environments, drives solute transport in rivers and many important biogeochemical processes. To improve understanding of these processes through visual demonstration, we created a hyporheic flow simulation in the multi-agent computer modeling platform NetLogo. The simulation shows virtual tracer flowing through a streambed covered with two-dimensional bedforms. Sediment, flow, and bedform characteristics are used as input variables for the model. We illustrate how these simulations match experimental observations from laboratory flume experiments based on measured input parameters. Dye is injected into the flume sediments to visualize the porewater flow. For comparison virtual tracer particles are placed at the same locations in the simulation. This coupled simulation and lab experiment has been used successfully in undergraduate and graduate laboratories to directly visualize river-porewater interactions and show how physically-based flow simulations can reproduce environmental phenomena. Students took photographs of the bed through the transparent flume walls and compared them to shapes of the dye at the same times in the simulation. This resulted in very similar trends, which allowed the students to better understand both the flow patterns and the mathematical model. The simulations also allow the user to quickly visualize the impact of each input parameter by running multiple simulations. This process can also be used in research applications to illustrate basic processes, relate interfacial fluxes and porewater transport, and support quantitative process-based modeling.

17.
Front Psychol ; 6: 1031, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26257687

RESUMO

There is much behavioral and neurophysiological evidence in support of the idea that seeing a tool activates motor components of action related to the perceived object (e.g., grasping, use manipulation). However, the question remains as to whether the processing of the motor components associated with the tool is automatic or depends on the situation, including the task and the modality of tool presentation. The present study investigated whether the activation of motor components involved in tool use in response to the simple perception of a tool is influenced by the link between prime and target tools, as well as by the modality of presentation, in perceptual or motor tasks. To explore this issue, we manipulated the similarity of gesture involved in the use of the prime and target (identical, similar, different) with two tool presentation modalities of the presentation tool (visual or auditory) in perceptual and motor tasks. Across the experiments, we also manipulated the relevance of the prime (i.e., associated or not with the current task). The participants saw a first tool (or heard the sound it makes), which was immediately followed by a second tool on which they had to perform a perceptual task (i.e., indicate whether the second tool was identical to or different from the first tool) or a motor task (i.e., manipulate the second tool as if it were the first tool). In both tasks, the similarity between the gestures employed for the first and the second tool was manipulated (Identical, Similar or Different gestures). The results showed that responses were faster when the manipulation gestures for the two tools were identical or similar, but only in the motor task. This effect was observed irrespective of the modality of presentation of the first tool, i.e., visual or auditory. We suggest that the influence of manipulation gesture on response time depends on the relevance of the first tool in motor tasks. We discuss these motor activation results in terms of the relevance and demands of the tasks.

18.
AJR Am J Roentgenol ; 202(6): 1383-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24848839

RESUMO

OBJECTIVE: In breast-conserving surgery for nonpalpable breast cancers, surgical reexcision rates are lower with radioactive seed localization (RSL) than wire localization. We evaluated the cost-benefit of switching from wire localization to RSL in two competing payment systems: a fee-for-service (FFS) system and a bundled payment system, which is typical for accountable care organizations. MATERIALS AND METHODS: A Monte Carlo simulation was developed to compare the cost-benefit of RSL and wire localization. Equipment utilization, procedural workflows, and regulatory overhead differentiate the cost between RSL and wire localization. To define a distribution of possible cost scenarios, the simulation randomly varied cost drivers within fixed ranges determined by hospital data, published literature, and expert input. Each scenario was replicated 1000 times using the pseudorandom number generator within Microsoft Excel, and results were analyzed for convergence. RESULTS: In a bundled payment system, RSL reduced total health care cost per patient relative to wire localization by an average of $115, translating into increased facility margin. In an FFS system, RSL reduced total health care cost per patient relative to wire localization by an average of $595 but resulted in decreased facility margin because of fewer surgeries. CONCLUSION: In a bundled payment system, RSL results in a modest reduction of cost per patient over wire localization and slightly increased margin. A fee-for-service system suffers moderate loss of revenue per patient with RSL, largely due to lower reexcision rates. The fee-for-service system creates a significant financial disincentive for providers to use RSL, although it improves clinical outcomes and reduces total health care costs.


Assuntos
Organizações de Assistência Responsáveis/economia , Braquiterapia/economia , Neoplasias da Mama/economia , Neoplasias da Mama/terapia , Planos de Pagamento por Serviço Prestado/economia , Mastectomia Segmentar/economia , Cirurgia Assistida por Computador/economia , Organizações de Assistência Responsáveis/estatística & dados numéricos , Idoso , Braquiterapia/estatística & dados numéricos , Neoplasias da Mama/epidemiologia , Simulação por Computador , Análise Custo-Benefício , Planos de Pagamento por Serviço Prestado/estatística & dados numéricos , Feminino , Custos de Cuidados de Saúde , Humanos , Mastectomia Segmentar/instrumentação , Mastectomia Segmentar/estatística & dados numéricos , Pessoa de Meia-Idade , Modelos Econômicos , Modelos Estatísticos , Método de Monte Carlo , Prevalência , Reoperação/economia , Reoperação/estatística & dados numéricos , Cirurgia Assistida por Computador/estatística & dados numéricos , Estados Unidos
19.
PLoS One ; 9(4): e96154, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24777029

RESUMO

The present study focused on priming effects on pointing with everyday objects. In a set of four experiments, a visuomotor priming paradigm was used to investigate the nature of visuomotor processing (automatic versus task relevant). By manipulating congruency of orientation and location we found that location congruency facilitates the initiation time of pointing whereas orientation congruency does not. We provide evidence to show that motor planning is influenced by the goal of the action, and that how visual information is processed and held in memory depends on the task relevance. These data are consistent with the proposed interaction between visuomotor and higher processes during the planning and execution of actions such as pointing.


Assuntos
Memória/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Feminino , Humanos , Masculino , Adulto Jovem
20.
Nat Nanotechnol ; 9(6): 453-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24747840

RESUMO

Strong interactions, or correlations, between the d or f electrons in transition-metal oxides lead to various types of metal-insulator transitions that can be triggered by external parameters such as temperature, pressure, doping, magnetic fields and electric fields. Electric-field-induced metallization of such materials from their insulating states could enable a new class of ultrafast electronic switches and latches. However, significant questions remain about the detailed nature of the switching process. Here, we show, in the canonical metal-to-insulator transition system V2O3, that ultrafast voltage pulses result in its metallization only after an incubation time that ranges from ∼150 ps to many nanoseconds, depending on the electric field strength. We show that these incubation times can be accounted for by purely thermal effects and that intrinsic electronic-switching mechanisms may only be revealed using larger electric fields at even shorter timescales.

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