5,627 research outputs found
Persistence of two genotypes of Neisseria gonorrhoeae during transmission.
Isolates of Neisseria gonorrhoeae were tested using a highly discriminatory typing method, opa typing, to examine the genetic diversity over a 2-year study period of isolates from all consecutive patients with gonorrhea attending the Genitourinary Medicine clinic in Sheffield, United Kingdom. Two opa genotypes were detected throughout the 2-year time period and comprised 41% of all strains tested. The persistence of two opa types was investigated further to determine the apparent genetic stability, by examining the ability of isolates to undergo intragenic and intergenic recombination and mutation in vitro. Intragenic recombination or mutation involving the opa genes of N. gonorrhoeae in the selected isolates was not detected, but intergenic recombination did occur. opa genes of N. gonorrhoeae in vivo appear to diversify primarily through intergenic recombination. Intergenic recombination in vivo would require the presence of a mixed gonococcal infection, in which an individual is concurrently colonized with more than one strain of N. gonorrhoeae. We propose that the level of diversity of opa genotypes in a population is linked to the degree of sexual mixing of individuals and the incidence of mixed infections of N. gonorrhoeae
The Stratigraphic Record of Pre-breakup Geodynamics: Evidence from the Barrow Delta, offshore Northwest Australia
The structural and stratigraphic evolution of rift basins and passive margins has been widely studied, with many analyses demonstrating that delta systems can provide important records of post-rift geodynamic processes. However, the apparent lack of ancient syn-breakup delta systems and the paucity of seismic imaging across continent-ocean boundaries means the transition from continental rifting to oceanic spreading remains poorly understood. The Early Cretaceous Barrow Group of the North Carnarvon Basin, offshore NW Australia was a major deltaic system that formed during the latter stages of continental rifting, and represents a rich sedimentary archive, documenting uplift, subsidence and erosion of the margin. We use a regional database of 2D and 3D seismic and well data to constrain the internal architecture of the Barrow Group. Our results highlight three major depocentres: the Exmouth and Barrow sub-basins, and southern Exmouth Plateau. Over-compaction of pre-Cretaceous sedimentary rocks in the South Carnarvon Basin, and pervasive reworking of Permian and Triassic palynomorphs in the offshore Barrow Group, suggests that the onshore South Carnarvon Basin originally contained a thicker sedimentary succession, which was uplifted and eroded prior to breakup. Backstripping of sedimentary successions encountered in wells in the Exmouth Plateau depocentre indicate anomalously rapid tectonic subsidence (≤0.24 mm yr-1) accommodated Barrow Group deposition, despite evidence for minimal, contemporaneous upper crustal extension. Our results suggest that classic models of uniform extension cannot account for the observations of uplift and subsidence in the North Carnarvon Basin, and may indicate a period of depth-dependent extension or dynamic topography preceding breakup
Global oceanic emission of ammonia: constraints from seawater and atmospheric observations
Current global inventories of ammonia emissions identify the ocean as the largest natural
source. This source depends on seawater pH, temperature, and the concentration of total seawater
ammonia (NHx(sw)), which reflects a balance between remineralization of organic matter, uptake by
plankton, and nitrification. Here we compare [NHx(sw)] from two global ocean biogeochemical models
(BEC and COBALT) against extensive ocean observations. Simulated [NHx(sw)] are generally biased high.
Improved simulation can be achieved in COBALT by increasing the plankton affinity for NHx within observed
ranges. The resulting global ocean emissions is 2.5 TgN a−1, much lower than current literature values
(7–23 TgN a−1), including the widely used Global Emissions InitiAtive (GEIA) inventory (8 TgN a−1). Such
a weak ocean source implies that continental sources contribute more than half of atmospheric NHx over
most of the ocean in the Northern Hemisphere. Ammonia emitted from oceanic sources is insufficient to
neutralize sulfate aerosol acidity, consistent with observations. There is evidence over the Equatorial Pacific
for a missing source of atmospheric ammonia that could be due to photolysis of marine organic nitrogen at
the ocean surface or in the atmosphere. Accommodating this possible missing source yields a global ocean
emission of ammonia in the range 2–5 TgN a−1, comparable in magnitude to other natural sources from
open fires and soils
Incidence, causes and correlates of maternal near‐miss morbidity: a multi‐centre cross‐sectional study
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/1/bjo15578-sup-0009-ICMJES9.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/2/bjo15578-sup-0008-ICMJES8.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/3/bjo15578-sup-0002-ICMJES2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/4/bjo15578-sup-0003-ICMJES3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/5/bjo15578_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/6/bjo15578-sup-0004-ICMJES4.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/7/bjo15578-sup-0005-ICMJES5.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/8/bjo15578.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/9/bjo15578-sup-0007-ICMJES7.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/10/bjo15578-sup-0006-ICMJES6.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149236/11/bjo15578-sup-0001-ICMJES1.pd
Efficacy of an intensive outpatient rehabilitation program in alcoholism: Predictors of outcome 6 months after treatment
Treatment of alcohol-dependent patients was primarily focused on inpatient settings in the past decades. The efficacy of these treatment programs has been evaluated in several studies and proven to be sufficient. However, with regard to the increasing costs in public healthcare systems, questions about alternative treatment strategies have been raised. Meanwhile, there is growing evidence that outpatient treatment might be comparably effective as inpatient treatment, at least for subgroups of alcohol dependents. On that background, the present study aimed to evaluate the efficacy of a high-structured outpatient treatment program in 103 alcohol-dependent patients. 74 patients (72%) terminated the outpatient treatment regularly. At 6 months' follow-up, 95% patients were successfully located and personally re-interviewed. Analyses revealed that 65 patients (64%) were abstinent at the 6-month follow-up evaluation and 37 patients ( 36%) were judged to be non-abstinent. Pretreatment variables which were found to have a negative impact (non-abstinence) on the 6-month outcome after treatment were a higher severity of alcohol dependence measured by a longer duration of alcohol dependence, a higher number of prior treatments and a stronger alcohol craving (measured by the Obsessive Compulsive Drinking Scale). Further patients with a higher degree of psychopathology measured by the Beck Depression Inventory (depression) and State-Trait Anxiety Inventory (anxiety) relapsed more often. In summary, results of this study indicate a favorable outcome of socially stable alcohol-dependent patients and patients with a lower degree of depression, anxiety and craving in an intensive outpatient rehabilitation program
Laboratory comparison of aging characteristics of warm mix asphalts involving natural and synthetic water containing additives
When comparing the aging characteristics of hot and warm mix asphalts from a technical point of view, it can intuitively be expected that a warm mix asphalt would be less subjected to aging-induced failures due to lower application temperatures. Since the side effects of warm asphalt technology should be investigated distinctly. This study addresses the aging investigation of properties of bituminous mixtures containing two (i.e., natural and synthetic zeolite) water based additives available on the market. Within the scope of this study, short- and long-term aging conditions were simulated on mixtures containing various contents of additives as well as on control specimens. The aging indices were determined based on the hardness ratio employing indirect tensile strength values in order to investigate the aging induced failures betide by time. Aging indices showed that the specimens with water containing additives demonstrate relatively better resistance against hardening than conventional hot mix asphalt specimens
Increasing confidence and changing behaviors in primary care providers engaged in genetic counselling.
BackgroundScreening and counseling for genetic conditions is an increasingly important part of primary care practice, particularly given the paucity of genetic counselors in the United States. However, primary care physicians (PCPs) often have an inadequate understanding of evidence-based screening; communication approaches that encourage shared decision-making; ethical, legal, and social implication (ELSI) issues related to screening for genetic mutations; and the basics of clinical genetics. This study explored whether an interactive, web-based genetics curriculum directed at PCPs in non-academic primary care settings was superior at changing practice knowledge, attitudes, and behaviors when compared to a traditional educational approach, particularly when discussing common genetic conditions.MethodsOne hundred twenty one PCPs in California and Pennsylvania physician practices were randomized to either an Intervention Group (IG) or Control Group (CG). IG physicians completed a 6 h interactive web-based curriculum covering communication skills, basics of genetic testing, risk assessment, ELSI issues and practice behaviors. CG physicians were provided with a traditional approach to Continuing Medical Education (CME) (clinical review articles) offering equivalent information.ResultsPCPs in the Intervention Group showed greater increases in knowledge compared to the Control Group. Intervention PCPs were also more satisfied with the educational materials, and more confident in their genetics knowledge and skills compared to those receiving traditional CME materials. Intervention PCPs felt that the web-based curriculum covered medical management, genetics, and ELSI issues significantly better than did the Control Group, and in comparison with traditional curricula. The Intervention Group felt the online tools offered several advantages, and engaged in better shared decision making with standardized patients, however, there was no difference in behavior change between groups with regard to increases in ELSI discussions between PCPs and patients.ConclusionWhile our intervention was deemed more enjoyable, demonstrated significant factual learning and retention, and increased shared decision making practices, there were few differences in behavior changes around ELSI discussions. Unfortunately, barriers to implementing behavior change in clinical genetics is not unique to our intervention. Perhaps the missing element is that busy physicians need systems-level support to engage in meaningful discussions around genetics issues. The next step in promoting active engagement between doctors and patients may be to put into place the tools needed for PCPs to easily access the materials they need at the point-of-care to engage in joint discussions around clinical genetics
Next-generation sequencing of the soil nematode community enables the sustainability of banana plantations to be monitored
Uganda faces a considerable challenge to match its food production to an annual population growth rate of 3%. Cooking bananas are the country's most produced staple crop but the annual national harvest is not increasing. The crop grows on infertile soils that are normally fertilised organically and often susceptible to erosion. Soil nematodes are well-established as bioindicators of soil quality that can support environmental monitoring and assessment of the sustainability of agricultural systems. These invertebrates are a highly ranked indicator of biodiversity with molecular approaches available. Consequently, we have applied next-generation DNA sequencing of soil nematodes to evaluate soil quality of Ugandan banana plantations. The aim is to establish a method for constructing an aspect of an environmental biosafety dossier with the future aim of assessing the impact of transgenic crops and improving current cropping systems. The soil samples did not differ significantly in any of the measured soil chemistry factors, soil texture or percentage of organic matter. Thirty taxons of soil nematodes other than the plant parasites were recovered from soil supporting nine banana plantations plus three each from coffee and banana-coffee interplants from East and West Uganda. Cluster analysis correctly allocated each plantation to the crop/intercrop being grown when based on the abundance of taxa rather than taxa presence or absence. This indicates that the host has considerable effects on the abundance of specific nematode species within the soil. Overall, nematodes were more abundant in soil from coffee plantations than from banana-coffee interplants with the lowest values being from fields supporting just banana. Only the basal and trophic diversity indices and the percentage of nematodes that are rapid colonisers varied between the three plantation types. The soil of all fifteen plantations can be classified as having a mature soil web condition with low physical disturbance, limited chemical stressors, moderately high nutrient enrichment and balanced decomposition channels
The influence of competing root symbionts on below-ground plant resource allocation
1. Plants typically interact with multiple above- and below-ground organisms simultaneously, with their symbiotic relationships spanning a continuum ranging from mutualism, such as with arbuscular mycorrhizal fungi (AMF), to parasitism, including symbioses with plant-parasitic nematodes (PPN).
2. Although research is revealing the patterns of plant resource allocation to mutualistic AMF partners under different host and environmental constraints, the root ecosystem, with multiple competing symbionts, is often ignored. Such competition is likely to heavily influence resource allocation to symbionts.
3. Here, we outline and discuss the competition between AMF and PPN for the finite supply of host plant resources, highlighting the need for a more holistic understanding of the influence of below-ground interactions on plant resource allocation. Based on recent developments in our understanding of other symbiotic systems such as legume–rhizobia and AMF-aphid-plant, we propose hypotheses for the distribution of plant resources between contrasting below-ground symbionts and how such competition may affect the host.
4. We identify relevant knowledge gaps at the physiological and molecular scales which, if resolved, will improve our understanding of the true ecological significance and potential future exploitation of AMF-PPN-plant interactions in order to optimize plant growth. To resolve these outstanding knowledge gaps, we propose the application of well-established methods in isotope tracing and nutrient budgeting to monitor the movement of nutrients between symbionts. By combining these approaches with novel time of arrival experiments and experimental systems involving multiple plant hosts interlinked by common mycelial networks, it may be possible to reveal the impact of multiple, simultaneous colonizations by competing symbionts on carbon and nutrient flows across ecologically important scales
An experimental test of non-local realism
Most working scientists hold fast to the concept of 'realism' - a viewpoint
according to which an external reality exists independent of observation. But
quantum physics has shattered some of our cornerstone beliefs. According to
Bell's theorem, any theory that is based on the joint assumption of realism and
locality (meaning that local events cannot be affected by actions in space-like
separated regions) is at variance with certain quantum predictions. Experiments
with entangled pairs of particles have amply confirmed these quantum
predictions, thus rendering local realistic theories untenable. Maintaining
realism as a fundamental concept would therefore necessitate the introduction
of 'spooky' actions that defy locality. Here we show by both theory and
experiment that a broad and rather reasonable class of such non-local realistic
theories is incompatible with experimentally observable quantum correlations.
In the experiment, we measure previously untested correlations between two
entangled photons, and show that these correlations violate an inequality
proposed by Leggett for non-local realistic theories. Our result suggests that
giving up the concept of locality is not sufficient to be consistent with
quantum experiments, unless certain intuitive features of realism are
abandoned.Comment: Minor corrections to the manuscript, the final inequality and all its
conclusions do not change; description of corrections (Corrigendum) added as
new Appendix III; Appendix II replaced by a shorter derivatio
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