406 research outputs found
Sensitivity of codispersion to noise and error in ecological and environmental data
Codispersion analysis is a new statistical method developed to assess spatial
covariation between two spatial processes that may not be isotropic or
stationary. Its application to anisotropic ecological datasets have provided
new insights into mechanisms underlying observed patterns of species
distributions and the relationship between individual species and underlying
environmental gradients. However, the performance of the codispersion
coefficient when there is noise or measurement error ("contamination") in the
data has been addressed only theoretically. Here, we use Monte Carlo
simulations and real datasets to investigate the sensitivity of codispersion to
four types of contamination commonly seen in many real-world environmental and
ecological studies. Three of these involved examining codispersion of a spatial
dataset with a contaminated version of itself. The fourth examined differences
in codisperson between plants and soil conditions, where the estimates of soil
characteristics were based on complete or thinned datasets. In all cases, we
found that estimates of codispersion were robust when contamination, such as
data thinning, was relatively low (<15\%), but were sensitive to larger
percentages of contamination. We also present a useful method for imputing
missing spatial data and discuss several aspects of the codispersion
coefficient when applied to noisy data to gain more insight about the
performance of codispersion in practice.Comment: 20 pages, 14 figure
Pricing in inflationary times: The penny drops
How does the frequency and magnitude of micro-price rises and falls relate to macroeconomic crisis, as well as moderation? Weekly micropricing behaviour in British groceries was investigated across three leading retailers over the moderation period 2004–7 and the crisis period 2008–10. We find significant price flexibility sharply distinguished from behaviour observed in most previous works. Downward price flexibility increased markedly in 2008. Overall basket prices rise, but significantly more individual prices fall than rise in the latter period. Tests of obfuscation in price setting suggested that large numbers of small price falls were used to disguise the basket price rises
Association of RENAL nephrometry score with outcomes of minimally invasive partial nephrectomy
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98294/1/iju3222.pd
Species Diversity Associated with Foundation Species in Temperate and Tropical Forests
Foundation species define and structure ecological communities but are difficult to identify before they are declining. Yet, their defining role in ecosystems suggests they should be a high priority for protection and management while they are still common and abundant. We used comparative analyses of six large forest dynamics plots spanning a temperate-to-tropical gradient in the Western Hemisphere to identify statistical “fingerprints” of potential foundation species based on their size-frequency and abundance-diameter distributions, and their spatial association with five measures of diversity of associated woody plant species. Potential foundation species are outliers from the common “reverse-J” size-frequency distribution, and have negative effects on alpha diversity and positive effects on beta diversity at most spatial lags and directions. Potential foundation species also are more likely in temperate forests, but foundational species groups may occur in tropical forests. As foundation species (or species groups) decline, associated landscape-scale (beta) diversity is likely to decline along with them. Preservation of this component of biodiversity may be the most important consequence of protecting foundation species while they are still common
Using codispersion analysis to quantify and understand spatial patterns in species-environment relationships
• The analysis of spatial patterns in species–environment relationships can provide new insights into the niche requirements and potential co-occurrence of species, but species abundance and environmental data are routinely collected at different spatial scales. Here, we investigate the use of codispersion analysis to measure and assess the scale, directionality and significance of complex relationships between plants and their environment in large forest plots.
• We applied codispersion analysis to both simulated and field data on spatially located tree species basal area and environmental variables. The significance of the observed bivariate spatial associations between the basal area of key species and underlying environmental variables was tested using three null models.
• Codispersion analysis reliably detected directionality (anisotropy) in bivariate species–environment relationships and identified relevant scales of effects. Null model-based significance tests applied to codispersion analyses of forest plot data enabled us to infer the extent to which environmental conditions, tree sizes and/or tree spatial positions underpinned the observed basal area–environment relationships, or whether relationships were a result of other unmeasured factors.
• Codispersion analysis, combined with appropriate null models, can be used to infer hypothesized ecological processes from spatial patterns, allowing us to start disentangling the possible drivers of plant species–environment relationships
The long-term impact of Multi-Systemic Therapy: an experiential study of the adolescent-young adult life transition
This qualitative study examines the possible long term impact of Multi-systemic therapy (MST) as young people experience the transition from adolescence to young adulthood. MST is an intensive intervention aimed at reducing antisocial behavior among young people.
Interviews were conducted with 32 young people aged 16-22 years at their 48-month follow-up as part of the Systemic Therapy for At Risk Teens (START) evaluation trial in the UK. Sixteen participants had received MST while sixteen received management as usual (MAU). Interviews addressed participants’ current life experiences and were analysed with interpretative phenomenological analysis (IPA). The inductive qualitative analysis data were transformed into numerical data. Interview extracts were coded as either forward-looking and hopeful (‘mature’) or static and frustrated (‘stuck’). Among males, significantly more mature outcomes were found among participants who had received MST compared with MAU. No differences were seen between the female groups. A detailed qualitative commentary shows how the constructs mature and stuck are manifest across the four domains.
The findings suggest that working with an MST therapist during adolescence helped young men cultivate more mature, forward-looking viewpoints and life activities four years later when transitioning into adulthood. Findings are discussed in relation to relevant theory and practical applications
Using new technologies to promote weight management: a randomised controlled trial study protocol
Background: Over the last three decades, overweight and obesity and the associated health consequences have become global public health priorities. Methods that have been tried to address this problem have not had the desired impact, suggesting that other approaches need to be considered. One of the lessons learned throughout these attempts is that permanent weight loss requires sustained dietary and lifestyle changes, yet adherence to weight management programs has often been noted as one of the biggest challenges. This trial aims to address this issue by examining whether social media, as a potential health promotion tool, will improve adherence to a weight management program. To test the effectiveness of this measure, the designated program will be delivered via the popular social networking site Facebook, and compared to a standard delivery method that provides exactly the same content but which is communicated through a pamphlet. The trial will be conducted over a period of twelve weeks, with a twelve week follow-up. Although weight loss is expected, this study will specifically investigate the effectiveness of social media as a program delivery method. The program utilised will be one that has already been proven to achieve weight loss, namely The CSIRO Total Wellbeing Diet.Methods/design: This project will be conducted as a 3-arm randomised controlled trial. One hundred and twenty participants will be recruited from the Perth community, and will be randomly assigned to one of the following three groups: the Facebook group, the pamphlet group, or a control group. The Facebook Group will receive the weight management program delivered via a closed group in Facebook, the Pamphlet Group will be given the same weight management program presented in a booklet, and the Control Group will follow the Australian Dietary Guidelines and the National Physical Activity Guidelines for Adults as usual care. Change in weight, body composition and waist circumference will be initial indicators of adherence to the program. Secondary outcome measures will be blood glucose, insulin, blood pressure, arterial stiffness, physical activity, eating behaviour, mental well-being (stress, anxiety, and depression), social support, self-control, self-efficacy, Facebook activity, and program evaluation. Discussion: It is expected that this trial will support the use of social media - a source of social support and information sharing - as a delivery method for weight management programs, enhancing the reduction in weight expected from dietary and physical activity changes. Facebook is a popular, easy to access and cost-effective online platform that can be used to assist the formation of social groups, and could be translated into health promotion practice relatively easily. It is anticipated in the context of the predicted findings that social media will provide an invaluable resource for health professionals and patients alike
Galaxy And Mass Assembly (GAMA): The effect of galaxy group environment on active galactic nuclei
In galaxy clusters, efficiently accreting active galactic nuclei (AGN) are preferentially located in the infall regions of the cluster projected phase-space, and are rarely found in the cluster core. This has been attributed to both an increase in triggering opportunities for infalling galaxies, and a reduction of those mechanisms in the hot, virialised, cluster core. Exploiting the depth and completeness (98 per cent at r9.9 in 695 groups with 11.53≤log 10 (M 200 /M ⊙ )≤14.56 at z13.5 , AGN are preferentially found in the infalling galaxy population with 3.6σ confidence. At lower halo masses we observe no difference in AGN fraction between core and infalling galaxies. These observations support a model where a reduced number of low-speed interactions, ram pressure stripping and intra-group/cluster medium temperature, the dominance of which increase with halo mass, work to inhibit AGN in the cores of groups and clusters with log 10 (M 200 /M ⊙ )>13.5 , but do not significantly affect nuclear activity in cores of less massive structures
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
PHANGS-JWST First Results: A Global and Moderately Resolved View of Mid-Infrared and CO Line Emission from Galaxies at the Start of the JWST Era
We explore the relationship between mid-infrared (mid-IR) and CO rotational
line emission from massive star-forming galaxies, which is one of the tightest
scalings in the local universe. We assemble a large set of unresolved and
moderately ( kpc) spatially resolved measurements of CO (1-0) and CO
(2-1) intensity, , and mid-IR intensity, , at 8, 12,
22, and 24m. The vs. relationship is reasonably
described by a power law with slopes and normalization K km s at MJy sr. Both the slopes
and intercepts vary systematically with choice of line and band. The comparison
between the relations measured for CO~(1-0) and CO (2-1) allow us to infer that
, in good agreement with other work. The
m and m bands, with strong PAH features, show steeper CO vs.
mid-IR slopes than the m and m, consistent with PAH emission
arising not just from CO-bright gas but also from atomic or CO-dark gas. The
CO-to-mid-IR ratio correlates with global galaxy stellar mass () and
anti-correlates with SFR/. At kpc resolution, the first four
PHANGS-JWST targets show CO to mid-IR relationships that are quantitatively
similar to our larger literature sample, including showing the steep
CO-to-mid-IR slopes for the JWST PAH-tracing bands, although we caution that
these initial data have a small sample size and span a limited range of
intensities.Comment: 29 pages, 13 figures, key quantitative results in Table 3, Accepted
as part of a PHANGS-JWST Focus Issue to appear in Ap
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