546 research outputs found

    A novel examination of none-of-the-above as it influences examinee item responses

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    It is imperative to collect validity evidence prior to interpreting and using test scores. During the process of collecting validity evidence, test developers should consider whether test scores are contaminated by sources of extraneous information. This is referred to as construct irrelevant variance, or the “degree to which test scores are affected by processes that are extraneous to the test’s intended purpose” (AERA et al., 2014, p. 12). One possible source of construct irrelevant variance is violating item-writing guidelines, such as to “avoid the use of none-of-the-above” in multiple-choice items (Rodriguez, 2016, p. 268). Numerous studies have been conducted with regards to how none-of-the-above (NOTA) impacts item statistics, such as item difficulty, item discrimination, and test score reliability. The impacts of NOTA on item statistics are mixed and often depend on whether NOTA is the correct or incorrect option. In the case of NOTA as the incorrect option, NOTA tends to be more frequently selected by examinees (Garcia-Perez, 1993; Frary, 1991). This increased selection is hypothesized to be due to a potential selection tendency that examinees possess toward NOTA (Butler, 2018). While this tendency toward selecting NOTA is hypothesized in the literature, there has not yet been a study which tests this hypothesis. In the current study, I extended previous NOTA literature to explore whether item difficulty varies across groups of examinees who receive a test with NOTA and a test without NOTA, after controlling for examinee ability. I also tested whether there is a hypothesized selection tendency toward NOTA. Overall, as described in previous research, NOTA resulted in mixed results. I discuss these results, as well as future areas of NOTA research

    The effects of undesirable distractors on estimates of ability

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    Distractors, or the incorrect options, are an important part of the multiple-choice item. Previous literature has supported the inclusion of distractors when estimating abilities. While the effects of well-functioning distractors on estimates of ability have been examined, research has neglected to examine the effects of undesirable distractors on estimates of ability. Undesirable distractors are defined as distractors that are opposite of what test-developers expect or want distractors to behave. For instance, an upper lure distractor is one that high ability examinees select rather than selecting the correct answer. A simulation study was employed to determine these effects by varying undesirable distractor type, percentage of items containing undesirable distractors, and test length. Item responses were generated using the Thissen-Steinberg multiple-choice model for simulating undesirable distractors and the three-parameter logistic model for simulating normal items. Following data generation, item responses were analyzed using the three-parameter logistic model in SAS. An analysis of covariance (ANCOVA) was used to examine the effects of undesirable distractors on estimates of ability for bias and standard error. Multiple significant interactions were identified for bias and standard error. One type of undesirable distractor that was especially problematic was the lower lure distractor, where high ability examinees have a slightly lower, but still high, probability of being selected in comparison to the correct answer. Additionally, a longer test resulted in the least amount of bias and standard error. Overall, test-developers should pay attention to the functioning of distractors, as there are effects of these undesirable distractors on estimates of ability

    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

    Advancing Equity Planning Now

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    What can planners do to restore equity to their craft? Drawing upon the perspectives of a diverse group of planning experts, Advancing Equity Planning Now places the concepts of fairness and equal access squarely in the center of planning research and practice. Editors Norman Krumholz and Kathryn Wertheim Hexter provide essential resources for city leaders and planners, as well as for students and others, interested in shaping the built environment for a more just world.Advancing Equity Planning Now remind us that equity has always been an integral consideration in the planning profession. The historic roots of that ethical commitment go back more than a century. Yet a trend of growing inequality in America, as well as other recent socio-economic changes that divide the wealthiest from the middle and working classes, challenge the notion that a rising economic tide lifts all boats. When planning becomes mere place-making for elites, urban and regional planners need to return to the fundamentals of their profession. Although they have not always done so, planners are well-positioned to advocate for greater equity in public policies that address the multiple objectives of urban planning including housing, transportation, economic development, and the removal of noxious land uses in neighborhoods

    Phase II trial of standard versus increased transfusion volume in Ugandan children with acute severe anemia.

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    BACKGROUND: Severe anemia (SA, hemoglobin 6 g/dl: primary outcome) and 28-day survival. RESULTS: Median admission hemoglobin was 4.2 g/dl (IQR 3.1 to 4.9). Initial volume received followed the randomization strategy in 155 (97%) patients. By 24-hours, 70 (90%) children in the Tx30 arm had corrected SA compared to 61 (74%) in the Tx20 arm; cause-specific hazard ratio = 1.54 (95% confidence interval 1.09 to 2.18, P = 0.01). From admission to day 28 there was a greater hemoglobin increase from enrollment in Tx30 (global P <0.0001). Serious adverse events included one non-fatal allergic reaction and one death in the Tx30 arm. There were six deaths in the Tx20 arm (P = 0.12); three deaths were adjudicated as possibly related to transfusion, but none secondary to volume overload. CONCLUSION: A higher initial transfusion volume prescribed at hospital admission was safe and resulted in an accelerated hematological recovery in Ugandan children with SA. Future testing in a large, pragmatic clinical trial to establish the effect on short and longer-term survival is warranted. TRIAL REGISTRATION: ClinicalTrials.Gov identifier: NCT01461590 registered 26 October 2011

    The Molecular and Spatial Epidemiology of Typhoid Fever in Rural Cambodia.

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    Typhoid fever, caused by the bacterium Salmonella Typhi, is an endemic cause of febrile disease in Cambodia. The aim of this study was to better understand the epidemiology of pediatric typhoid fever in Cambodia. We accessed routine blood culture data from Angkor Hospital for Children (AHC) in Siem Reap province between 2007 and 2014, and performed whole genome sequencing (WGS) on the isolated bacteria to characterize the S. Typhi population. The resulting phylogenetic information was combined with conventional epidemiological approaches to investigate the spatiotemporal distribution of S. Typhi and population-level risk factors for reported disease. During the study period, there were 262 cases of typhoid within a 100 km radius of AHC, with a median patient age of 8.2 years (IQR: 5.1-11.5 years). The majority of infections occurred during the rainy season, and commune incidences as high as 11.36/1,000 in children aged <15 years were observed over the study period. A population-based risk factor analysis found that access to water within households and increasing distance from Tonle Sap Lake were protective. Spatial mapping and WGS provided additional resolution for these findings, and confirmed that proximity to the lake was associated with discrete spatiotemporal disease clusters. We confirmed the dominance of MDR H58 S. Typhi in this population, and found substantial evidence of diversification (at least seven sublineages) within this single lineage. We conclude that there is a substantial burden of pediatric typhoid fever in rural communes in Cambodia. Our data provide a platform for additional population-based typhoid fever studies in this location, and suggest that this would be a suitable setting in which to introduce a school-based vaccination programme with Vi conjugate vaccines

    Validation of a clinical-grade assay to measure donor-derived cell-free DNA in solid organ transplant recipients

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    [Abstract] The use of circulating cell-free DNA (cfDNA) as a biomarker in transplant recipients offers advantages over invasive tissue biopsy as a quantitative measure for detection of transplant rejection and immunosuppression optimization. However, the fraction of donor-derived cfDNA (dd-cfDNA) in transplant recipient plasma is low and challenging to quantify. Previously reported methods to measure dd-cfDNA require donor and recipient genotyping, which is impractical in clinical settings and adds cost. We developed a targeted next-generation sequencing assay that uses 266 single-nucleotide polymorphisms to accurately quantify dd-cfDNA in transplant recipients without separate genotyping. Analytical performance of the assay was characterized and validated using 1117 samples comprising the National Institute for Standards and Technology Genome in a Bottle human reference genome, independently validated reference materials, and clinical samples. The assay quantifies the fraction of dd-cfDNA in both unrelated and related donor-recipient pairs. The dd-cfDNA assay can reliably measure dd-cfDNA (limit of blank, 0.10%; limit of detection, 0.16%; limit of quantification, 0.20%) across the linear quantifiable range (0.2% to 16%) with across-run CVs of 6.8%. Precision was also evaluated for independently processed clinical sample replicates and is similar to across-run precision. Application of the assay to clinical samples from heart transplant recipients demonstrated increased levels of dd-cfDNA in patients with biopsy-confirmed rejection and decreased levels of dd-cfDNA after successful rejection treatment. This noninvasive clinical-grade sequencing assay can be completed within 3 days, providing the practical turnaround time preferred for transplanted organ surveillance

    A randomised controlled trial to evaluate the impact of indoor living space on dairy cow production, reproduction and behaviour

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    As a global society, we have a duty to provide suitable care and conditions for farmed livestock to protect animal welfare and ensure the sustainability of our food supply. The suitability and biological impacts of housing conditions for intensively farmed animals is a complex and emotive subject, yet poorly researched, meaning quantitative evidence to inform policy and legislation is lacking. Most dairy cows globally are housed for some duration during the year, largely when climatic conditions are unfavourable. However, the impact on biology, productivity and welfare of even the most basic housing requirement, the quantity of living space, remains unknown. We conducted a long-term (1-year), randomised controlled trial (CONSORT 10 guidelines) to investigate the impact of increased living space (6.5m2 vs 3m2 per animal) on critical aspects of cow biology, behaviour and productivity. Adult Holstein dairy cows (n = 150) were continuously and randomly allocated to a high or control living space group with all other aspects of housing remaining identical between groups. Compared to cows in the control living space group, cows with increased space produced more milk per 305d lactation (primiparous: 12,235L vs 11,592L, P < 0.01; multiparous: 14,746L vs 14,644L, P < 0.01) but took longer to become pregnant after calving (primiparous: 155d vs 83d, P = 0.025; multiparous: 133d vs 109d). In terms of behaviour, cows with more living space spent significantly more time in lying areas (65min/d difference; high space group: 12.43h/day, 95% CI = 11.70-13.29; control space group: 11.42h/day, 95% CI = 10.73-12.12) and significantly less time in passageways (64min/d), suggesting enhanced welfare when more space was provided. A key physiological difference between groups was that cows with more space spent longer ruminating each day. This is the first long term study in dairy cows to demonstrate that increased living space results in meaningful benefits in terms of productivity and behaviour and suggests that the interplay between farmed animals and their housed environment plays an important role in the concepts of welfare and sustainability of dairy farming

    A novel ciprofloxacin-resistant subclade of H58 Salmonella Typhi is associated with fluoroquinolone treatment failure.

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    The interplay between bacterial antimicrobial susceptibility, phylogenetics and patient outcome is poorly understood. During a typhoid clinical treatment trial in Nepal, we observed several treatment failures and isolated highly fluoroquinolone-resistant Salmonella Typhi (S. Typhi). Seventy-eight S. Typhi isolates were genome sequenced and clinical observations, treatment failures and fever clearance times (FCTs) were stratified by lineage. Most fluoroquinolone-resistant S. Typhi belonged to a specific H58 subclade. Treatment failure with S. Typhi-H58 was significantly less frequent with ceftriaxone (3/31; 9.7%) than gatifloxacin (15/34; 44.1%)(Hazard Ratio 0.19, p=0.002). Further, for gatifloxacin-treated patients, those infected with fluoroquinolone-resistant organisms had significantly higher median FCTs (8.2 days) than those infected with susceptible (2.96) or intermediately resistant organisms (4.01)(pS. Typhi clade internationally, but there are no data regarding disease outcome with this organism. We report an emergent new subclade of S. Typhi-H58 that is associated with fluoroquinolone treatment failure
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