932 research outputs found

    Examining the Development Effects of Modern-Era Streetcars: An Assessment of Portland and Seattle

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    Most U.S. cities pursuing streetcars are doing so primarily for their purported development effects, as opposed to for their transportation role, yet there is little evidence about the nature or magnitude of these development effects due to a scarcity of rigorous, empirical research. Most available work simply presents descriptive information about development outcomes (typically measured as changes in population, employment, land values, or permit activity) within streetcar corridors as indicators of the streetcar’s development effects. Alternate factors which may have influenced such results are often not considered, placing into question the validity of such measures.This study examines the development effects of streetcar investments in two U.S. cities that implemented streetcar service between 2000 and 2010: Portland, Oregon, and Seattle, Washington. The authors explore the development outcomes (here measured as the number of permits issued) through a combination of statistical analysis of development activity in the streetcar corridor and interviews with key streetcar stakeholders. The statistical results indicate that areas around Portland’s initial streetcar line experienced higher levels of development activity (more permits issued) than areas not served by the streetcar, although the differences in activity between served and not served areas since the opening of the second line have been insignificant. In Seattle, the areas around the streetcar line in the South Lake Union neighborhood experienced greater commercial development activity (commercial permits issued) but less residential activity than nearby unserved areas. The interviews provide important local context for the interpretation of the empirical results and highlight the continued importance of development as a rationale for streetcar investments, as well as to the limitations of the streetcar as a transportation service

    Trends in application of NIR and hyperspectral imaging for food authentication

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    Food fraud can cause damage to consumer health and affect their confidence, destroy brands and generate large economic losses in the industry. Food authenticity allows to identify if food composition, geographical origin, genetic variety and farming system corresponds to what has been declared on the label. Although there are currently standardized methods to identify certain adulterants, the complexity of the food, the complexity of the supply chain and the appearance of new adulterants require the continuous development of analytical techniques to detect food fraud. NIR and Hyperspectral imaging (HSI) in tandem with chemometrics are non-destructive, non-invasive and accurate techniques for food authentication. This review focuses on NIR and HIS approaches to food authentication, including adulteration by substitution, geographical origin and farming system. In this context, the advances in NIR and HSI approaches reported since 2014 are discussed regarding their potential use in food authentication. Both techniques have shown to have efficiency, precision and selectivity to detect adulterants and identify geographic origin, genetic variety and farming system. Portability and remote access are shown as the next step for the industrialization of NIR and HSI devices

    Estimating Gene Flow between Refuges and Crops: A Case Study of the Biological Control of Eriosoma lanigerum by Aphelinus mali in Apple Orchards

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    Parasitoid disturbance populations in agroecosystems can be maintained through the provision of habitat refuges with host resources. However, specialized herbivores that feed on different host plants have been shown to form host-specialized races. Parasitoids may subsequently specialize on these herbivore host races and therefore prefer parasitizing insects from the refuge, avoiding foraging on the crop. Evidence is therefore required that parasitoids are able to move between the refuge and the crop and that the refuge is a source of parasitoids, without being an important source of herbivore pests. A North-South transect trough the Chilean Central Valley was sampled, including apple orchards and surrounding Pyracantha coccinea (M. Roem) (Rosales: Rosacea) hedges that were host of Eriosoma lanigerum (Hemiptera: Aphididae), a globally important aphid pest of cultivated apples. At each orchard, aphid colonies were collected and taken back to the laboratory to sample the emerging hymenopteran parasitoid Aphelinus mali (Hymenoptera: Aphelinidae). Aphid and parasitoid individuals were genotyped using species-specific microsatellite loci and genetic variability was assessed. By studying genetic variation, natural geographic barriers of the aphid pest became evident and some evidence for incipient host-plant specialization was found. However, this had no effect on the population-genetic features of its most important parasitoid. In conclusion, the lack of genetic differentiation among the parasitoids suggests the existence of a single large and panmictic population, which could parasite aphids on apple orchards and on P. coccinea hedges. The latter could thus comprise a suitable and putative refuge for parasitoids, which could be used to increase the effectiveness of biological control. Moreover, the strong geographical differentiation of the aphid suggests local reinfestations occur mainly from other apple orchards with only low reinfestation from P. cocinnea hedges. Finally, we propose that the putative refuge could act as a source of parasitoids without being a major source of aphids

    Sex-Biased Evolutionary Forces Shape Genomic Patterns of Human Diversity

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    Comparisons of levels of variability on the autosomes and X chromosome can be used to test hypotheses about factors influencing patterns of genomic variation. While a tremendous amount of nucleotide sequence data from across the genome is now available for multiple human populations, there has been no systematic effort to examine relative levels of neutral polymorphism on the X chromosome versus autosomes. We analyzed ∼210 kb of DNA sequencing data representing 40 independent noncoding regions on the autosomes and X chromosome from each of 90 humans from six geographically diverse populations. We correct for differences in mutation rates between males and females by considering the ratio of within-human diversity to human-orangutan divergence. We find that relative levels of genetic variation are higher than expected on the X chromosome in all six human populations. We test a number of alternative hypotheses to explain the excess polymorphism on the X chromosome, including models of background selection, changes in population size, and sex-specific migration in a structured population. While each of these processes may have a small effect on the relative ratio of X-linked to autosomal diversity, our results point to a systematic difference between the sexes in the variance in reproductive success; namely, the widespread effects of polygyny in human populations. We conclude that factors leading to a lower male versus female effective population size must be considered as important demographic variables in efforts to construct models of human demographic history and for understanding the forces shaping patterns of human genomic variability

    Prevalence and sociodemographic determinants of public stigma towards people with HIV and its impact on HIV testing uptake: A cross-sectional study in 64 low- and middle-income countries

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    Background: HIV stigma and discrimination are drivers of adverse HIV outcomes because they deter individuals from engaging in the HIV care continuum. We estimate the prevalence of public stigma towards people with HIV, investigate individuals' sociodemographic determinants for reporting stigmatizing attitudes, and test the impact of HIV stigma on HIV testing uptake. Methods: This was an observational study based on an analysis of cross-sectional surveys from 64 low- and middle-income countries. We used nationally representative survey data for the population aged 15–49 years from 2015 to 2021, which was the latest available data. HIV public stigma was measured using an index of two questions about attitudes towards people with HIV. First, prevalence estimates of HIV stigma were calculated by country, across countries, and by sociodemographic characteristics. Second, country fixed-effects multivariable logistic regression models were fit to assess sociodemographic determinants of holding stigmatizing attitudes towards people with HIV. Additional logistic regression models assessed country-level income and HIV prevalence as determinants of stigma and assessed the role of HIV public stigma as a driver of testing uptake. Results: A total of 1 172 841 participants were included in the study. HIV stigma was prevalent in all countries, ranging from 12.87% in Rwanda to 90.58% in Samoa. There was an inverse dose–response association between HIV stigma and educational level, wealth quintile, and age group, whereby higher levels of each were associated with lower odds of holding stigmatized attitudes towards people with HIV. The odds of stigmatized attitudes were lower among men and individuals with adequate knowledge of HIV. HIV stigma was lower in countries with greater gross domestic product per capita and HIV prevalence. Holding stigmatized attitudes towards people with HIV was associated with lower testing uptake, including having ever tested or having tested in the last year. Conclusion: HIV stigma is present to a highly varying degree in all countries studied, so different approaches to reducing stigma towards people with HIV are required across settings. Action to eliminate HIV stigma is crucial if we are to progress towards ending HIV because holding stigmatized attitudes towards people with HIV was associated with reduced testin

    Tuberculosis in the Torres Strait: the lady doth test too much

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    Introduction: Smear-positive pulmonary tuberculosis (PTB) requires rapid diagnosis and treatment to prevent ongoing transmission. Collection of two sputum specimens is considered the minimum requirement for the diagnosis of PTB but current guidelines in the Torres Strait Islands, Australia, recommend three sputum specimens; this frequently delays treatment initiation. Methods: A retrospective study was performed to ascertain the diagnostic yield of sputum specimens collected in the Torres Strait Islands. The study assessed demographics and characteristics of all PTB cases diagnosed between 2000 and 2018, and assessed the diagnostic yield in 143 patients from whom at least three sputum specimens had been collected prior to treatment commencement. Incremental and cumulative yield was calculated for each sputum specimen. Data were further analysed using binary logistic regression to examine the association between selected characteristics and a smear-positive acid-fast bacilli (AFB) result. Results: Overall, AFB was detected from the first or second sputum specimen in 97 of 101 PTB cases that were sputum smear positive. A smear-positive result was more common (odds ratio 2.84, 95% confidence interval 1.08–7.46) for Papua New Guinea nationals compared to Australian born patients. Of the 429 samples collected, 76 (18%) were of poor quality and the association between poor quality specimens and smear-negative results was significant (p<0.01). Among sputum smear-negative cases, 5/42= (12%) had three consecutive poor quality specimens. The most common collection modality in adults was voluntary expectoration; done in 391/429 (91%) of all specimens collected. Alternative specimen collection methods were mainly used in children; induced sputum 1/429 (0.2%), gastric aspirate 26/429 (6%) and nasopharyngeal aspirate 7/429 (1.6%). Errors with labelling, packaging and transportation occurred in 44 specimens from 15 patients. Conclusion: Two good quality specimens ensure adequate diagnostic yield for PTB and a third specimen should only be collected from patients with two negative specimens who have persistent symptoms. Ideally, decentralised Xpert Ultra® should be the frontline diagnostic test in remote settings, especially in settings like the Torres Strait Islands with high rates of drugresistant TB

    Riesgos ergonómicos y su repercusión en el rendimiento laboral en los trabajadores de la empresa Astilleros Luguensi S.A.C – Chimbote 2022

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    La investigación tiene como objetivo general determinar si los riesgos ergonómicos repercuten en el rendimiento laboral en los trabajadores de la empresa Astilleros Luguensi S.A.C. se establece una metodología aplicada y del tipo preexperimental, esto con el fin de orientar la investigación a solucionar una problemática; la población establecida son los 30 colaboradores de todas las áreas de la empresa Astilleros Luguensi S.A.C. Los resultados mostraron que existen grandes deficiencias en la gestión de seguridad debido a que las medidas preventivas que se realizan no están relacionadas a la ergonomía; bajo estos preceptos se establecen programas de estiramientos enfocados a los resultados REBA, así como un programa de inspección y distribución de rutas de tránsito; la aplicación de todos estos elementos demostró un aumento del desempeño cercano al 30% en donde la dimensión con más alto índice es la rapidez ya que supera el 70% en casi todos los casos. La investigación concluye que la reducción de riesgos laborales aumenta la seguridad del trabajador y aunque no aumenta el ritmo de trabajo lo estabiliza por un largo tiempo lo que aumenta la rapidez en la realización de los trabajos en grandes periodos de tiempo

    Pancreatic Cancer Surgical Resection Margins: Molecular Assessment by Mass Spectrometry Imaging

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    International audienceBackgroundSurgical resection with microscopically negative margins remains the main curative option for pancreatic cancer; however, in practice intraoperative delineation of resection margins is challenging. Ambient mass spectrometry imaging has emerged as a powerful technique for chemical imaging and real-time diagnosis of tissue samples. We applied an approach combining desorption electrospray ionization mass spectrometry imaging (DESI-MSI) with the least absolute shrinkage and selection operator (Lasso) statistical method to diagnose pancreatic tissue sections and prospectively evaluate surgical resection margins from pancreatic cancer surgery.Methods and FindingsOur methodology was developed and tested using 63 banked pancreatic cancer samples and 65 samples (tumor and specimen margins) collected prospectively during 32 pancreatectomies from February 27, 2013, to January 16, 2015. In total, mass spectra for 254,235 individual pixels were evaluated. When cross-validation was employed in the training set of samples, 98.1% agreement with histopathology was obtained. Using an independent set of samples, 98.6% agreement was achieved. We used a statistical approach to evaluate 177,727 mass spectra from samples with complex, mixed histology, achieving an agreement of 81%. The developed method showed agreement with frozen section evaluation of specimen margins in 24 of 32 surgical cases prospectively evaluated. In the remaining eight patients, margins were found to be positive by DESI-MSI/Lasso, but negative by frozen section analysis. The median overall survival after resection was only 10 mo for these eight patients as opposed to 26 mo for patients with negative margins by both techniques. This observation suggests that our method (as opposed to the standard method to date) was able to detect tumor involvement at the margin in patients who developed early recurrence. Nonetheless, a larger cohort of samples is needed to validate the findings described in this study. Careful evaluation of the long-term benefits to patients of the use of DESI-MSI for surgical margin evaluation is also needed to determine its value in clinical practice.ConclusionsOur findings provide evidence that the molecular information obtained by DESI-MSI/Lasso from pancreatic tissue samples has the potential to transform the evaluation of surgical specimens. With further development, we believe the described methodology could be routinely used for intraoperative surgical margin assessment of pancreatic cancer
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