5,669 research outputs found
Factors Affecting the Microbiome of \u3ci\u3eIxodes scapularis\u3c/i\u3e and \u3ci\u3eAmblyomma americanum\u3c/i\u3e
The microbial community composition of disease vectors can impact pathogen establishment and transmission as well as on vector behavior and fitness. While data on vector microbiota are accumulating quickly, determinants of the variation in disease vector microbial communities are incompletely understood. We explored the microbiome of two human-biting tick species abundant in eastern North America (Amblyomma americanum and Ixodes scapularis) to identify the relative contribution of tick species, tick life stage, tick sex, environmental context and vertical transmission to the richness, diversity, and species composition of the tick microbiome. We sampled 89 adult and nymphal Ixodes scapularis (N = 49) and Amblyomma americanum (N = 40) from two field sites and characterized the microbiome of each individual using the v3-v4 hypervariable region of the 16S rRNA gene. We identified significant variation in microbial community composition due to tick species and life stage with lesser impact of sampling site. Compared to unfed nymphs and males, the microbiome of engorged adult female I. scapularis, as well as the egg masses they produced, were low in bacterial richness and diversity and were dominated by Rickettsia, suggesting strong vertical transmission of this genus. Likewise, microbiota of A. americanum nymphs and males were more diverse than those of adult females. Among bacteria of public health importance, we detected several different Rickettsia sequence types, several of which were distinct from known species. Borrelia was relatively common in I. scapularis but did not show the same level of sequence variation as Rickettsia. Several bacterial genera were significantly over-represented in Borrelia-infected I. scapularis, suggesting a potential interaction of facilitative relationship between these taxa; no OTUs were under-represented in Borrelia-infected ticks. The systematic sampling we conducted for this study allowed us to partition the variation in tick microbial composition as a function of tick- and environmentally-related factors. Upon more complete understanding of the forces that shape the tick microbiome it will be possible to design targeted experimental studies to test the impacts of individual taxa and suites of microbes on vector-borne pathogen transmission and on vector biology
Micro-ion Traps for Detection of (Pre)-Biotic Organic Compounds on Comets
Comets are currently believed to be a mixture of interstellar and nebular material. Many of the volatiles in comets are attributed to interstellar chemistry, because the same species of carbonaceous compounds are also observed in ices in interstellar molecular (ISM) clouds. Comets are thus likely to be a relatively pristine reservoir of primitive material and carbonaceous compounds in our solar system. They could be a major contributor to the delivery of prebiotic organic compounds, from which life emerged through impacts on early Earth. Mass spectrometers are very powerful tools to identify unknown chemicals, and much progress bas been made in miniaturizing mas spectrometers for space applications. Most miniatu rized mass spectrometers developed to date, however, are still relatively large, power hungry, complicated to assemble, and would have significant impact on space flight vehicle total payload and resource allocations
Global glacier change in the 21st century: Every increase in temperature matters
Glacier mass loss affects sea level rise, water resources, and natural hazards. We present global glacier projections, excluding the ice sheets, for shared socioeconomic pathways calibrated with data for each glacier. Glaciers are projected to lose 26 ¹ 6% (+1.5°C) to 41 ¹ 11% (+4°C) of their mass by 2100, relative to 2015, for global temperature change scenarios. This corresponds to 90 ¹ 26 to 154 ¹ 44 millimeters sea level equivalent and will cause 49 ¹ 9 to 83 ¹ 7% of glaciers to disappear. Mass loss is linearly related to temperature increase and thus reductions in temperature increase reduce mass loss. Based on climate pledges from the Conference of the Parties (COP26), global mean temperature is projected to increase by +2.7°C, which would lead to a sea level contribution of 115 ¹ 40 millimeters and cause widespread deglaciation in most mid-latitude regions by 2100
Advance diaspora diplomacy in a networked world
The role of diaspora in cultural exchange, international affairs and in economic development is now well established. What is new is the increasing proliferation of national strategies to harness them actively for public diplomacy. This article addresses the rise of Australiaâs only formal, global diaspora network: Advance â Australiaâs Global Community which has acted self-consciously to become an instrument of public diplomacy. Emerging from a small base in New York, Advance sought to âopen doorsâ for Australians in the worldâs biggest market. Cultivating a strong membership base of well-connected individuals in the arts, commerce and professions, Advance developed its network centrality by building partnerships with state governments, Australian universities and federal government agencies. As an elite organisation of high-profile Australians overseas, Advance has developed into a global organisation communicating Australian culture and economic achievements to both Australian national audiences and foreign constituencies
Variation in the Microbiota of Ixodes Ticks with Regard to Geography, Species, and Sex
Ixodes scapularis is the principal vector of Lyme disease on the East Coast and in the upper Midwest regions of the United States, yet the tick is also present in the Southeast, where Lyme disease is absent or rare. A closely related species, I. affinis, also carries the pathogen in the South but does not seem to transmit it to humans. In order to better understand the geographic diversity of the tick, we analyzed the microbiota of 104 adult I. scapularis and 13 adult I. affinis ticks captured in 19 locations in South Carolina, North Carolina, Virginia, Connecticut, and New York. Initially, ticks from 4 sites were analyzed by 454 pyrosequencing. Subsequently, ticks from these sites plus 15 others were analyzed by sequencing with an Illumina MiSeq machine. By both analyses, the microbiomes of female ticks were significantly less diverse than those of male ticks. The dissimilarity between tick microbiomes increased with distance between sites, and the state in which a tick was collected could be inferred from its microbiota. The genus Rickettsia was prominent in all locations. Borrelia was also present in most locations and was present at especially high levels in one site in western Virginia. In contrast, members of the family Enterobacteriaceae were very common in North Carolina I. scapularis ticks but uncommon in I. scapularis ticks from other sites and in North Carolina I. affinis ticks. These data suggest substantial variations in the Ixodes microbiota in association with geography, species, and sex
Health system barriers to strengthening vaccine-preventable disease surveillance and response in the context of decentralization: evidence from Georgia
BACKGROUND: A critical challenge in the health sector in developing countries is to ensure the quality and effectiveness of surveillance and public health response in an environment of decentralization. In Georgia, a country where there has been extensive decentralization of public health responsibilities over the last decade, an intervention was recently piloted to strengthen district-level local vaccine-preventable disease surveillance and response activities through improved capacity to analyze and use routinely collected data. The purpose of the study is 1) to assess the effectiveness of the intervention on motivation and perceived capacity to analyze and use information at the district-level, and 2) to assess the role that individual- and system-level factors play in influencing the effectiveness of the intervention. METHODS: A pre-post quasi-experimental research design is used for the quantitative evaluation. Data come from a baseline and two follow-up surveys of district-level health staff in 12 intervention and 3 control Center of Public Health (CPH) offices. These data were supplemented by record reviews in CPH offices as well as focus group discussions among CPH and health facility staff. RESULTS: The results of the study suggest that a number of expected improvements in perceived data availability and analysis occurred following the implementation of the intervention package, and that these improvements in analysis could be attributable to the intervention package. However, the study results also suggest that there exist several health systems barriers that constrained the effectiveness of the intervention in influencing the availability of data, analysis and response. CONCLUSION: To strengthen surveillance and response systems in Georgia, as well as in other countries, donor, governments, and other stakeholders should consider how health systems factors influence investments to improve the availability of data, analysis, and response. Linking the intervention to broader health sector reforms in management processes and organizational culture will be critical to ensure that efforts designed to promote evidence-based decision-making are successful, especially as they are scaled up to the national level
Perceptions of employability among London's low-paid: 'self-determination' or ethnicity?
We investigate how ethnicity, gender and other characteristics affect low-paid workersâ perceptions of their employability in Londonâs labour market, examining âself-determinationâ, ethnic and dual labour market theories. We find that perceptions vary considerably, both between genders and ethnicities and in the extent to which they are âjustifiedâ by human capital attributes. Optimism varies between genders and ethnic groups but individualsâ perceptions vary to an even greater extent within genders and ethnic groups. Hence, individual-level âself-determinationâ explanations of these perceptions appear to have greatest explanatory power though ethnic theories also have utility
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV
The t t-bar production cross section (sigma[t t-bar]) is measured in
proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS
experiment, corresponding to an integrated luminosity of 2.3 inverse
femtobarns. The measurement is performed in events with two leptons (electrons
or muons) in the final state, at least two jets identified as jets originating
from b quarks, and the presence of an imbalance in transverse momentum. The
measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/-
2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction
of the standard model.Comment: Replaced with published version. Included journal reference and DO
Combined search for the quarks of a sequential fourth generation
Results are presented from a search for a fourth generation of quarks
produced singly or in pairs in a data set corresponding to an integrated
luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in
2011. A novel strategy has been developed for a combined search for quarks of
the up and down type in decay channels with at least one isolated muon or
electron. Limits on the mass of the fourth-generation quarks and the relevant
Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a
simple extension of the standard model with a sequential fourth generation of
fermions. The existence of mass-degenerate fourth-generation quarks with masses
below 685 GeV is excluded at 95% confidence level for minimal off-diagonal
mixing between the third- and the fourth-generation quarks. With a mass
difference of 25 GeV between the quark masses, the obtained limit on the masses
of the fourth-generation quarks shifts by about +/- 20 GeV. These results
significantly reduce the allowed parameter space for a fourth generation of
fermions.Comment: Replaced with published version. Added journal reference and DO
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