646 research outputs found
Architecture of an Antagonistic Tree/Fungus Network: The Asymmetric Influence of Past Evolutionary History
Compartmentalization and nestedness are common patterns in ecological networks. The aim of this study was to elucidate some of the processes shaping these patterns in a well resolved network of host/pathogen interactions.Based on a long-term (1972-2005) survey of forest health at the regional scale (all French forests; 15 million ha), we uncovered an almost fully connected network of 51 tree taxa and 157 parasitic fungal species. Our analyses revealed that the compartmentalization of the network maps out the ancient evolutionary history of seed plants, but not the ancient evolutionary history of fungal species. The very early divergence of the major fungal phyla may account for this asymmetric influence of past evolutionary history. Unlike compartmentalization, nestedness did not reflect any consistent phylogenetic signal. Instead, it seemed to reflect the ecological features of the current species, such as the relative abundance of tree species and the life-history strategies of fungal pathogens. We discussed how the evolution of host range in fungal species may account for the observed nested patterns.Overall, our analyses emphasized how the current complexity of ecological networks results from the diversification of the species and their interactions over evolutionary times. They confirmed that the current architecture of ecological networks is not only dependent on recent ecological processes
Immunological and Metabolomic Impacts of Administration of Cry1Ab Protein and MON 810 Maize in Mouse
We have investigated the immunological and metabolomic impacts of Cry1Ab administration to mice, either as a purified protein or as the Cry1Ab-expressing genetically modified (GM) MON810 maize. Humoral and cellular specific immune responses induced in BALB/cJ mice after intra-gastric (i.g.) or intra-peritoneal (i.p.) administration of purified Cry1Ab were analyzed and compared with those induced by proteins of various immunogenic and allergic potencies. Possible unintended effects of the genetic modification on the pattern of expression of maize natural allergens were studied using IgE-immunoblot and sera from maize-allergic patients. Mice were experimentally sensitized (i.g. or i.p. route) with protein extracts from GM or non-GM maize, and then anti-maize proteins and anti-Cry1Ab–induced immune responses were analyzed. In parallel, longitudinal metabolomic studies were performed on the urine of mice treated via the i.g. route. Weak immune responses were observed after i.g. administration of the different proteins. Using the i.p. route, a clear Th2 response was observed with the known allergenic proteins, whereas a mixed Th1/Th2 immune response was observed with immunogenic protein not known to be allergenic and with Cry1Ab. This then reflects protein immunogenicity in the BALB/c Th2-biased mouse strain rather than allergenicity. No difference in natural maize allergen profiles was evidenced between MON810 and its non-GM comparator. Immune responses against maize proteins were quantitatively equivalent in mice treated with MON810 vs the non-GM counterpart and no anti-Cry1Ab–specific immune response was detected in mice that received MON810. Metabolomic studies showed a slight “cultivar” effect, which represented less than 1% of the initial metabolic information. Our results confirm the immunogenicity of purified Cry1Ab without evidence of allergenic potential. Immunological and metabolomic studies revealed slight differences in mouse metabolic profiles after i.g. administration of MON810 vs its non-GM counterpart, but no significant unintended effect of the genetic modification on immune responses was seen
Study of decays to the final state and evidence for the decay
A study of decays is performed for the first time
using data corresponding to an integrated luminosity of 3.0
collected by the LHCb experiment in collisions at centre-of-mass energies
of and TeV. Evidence for the decay
is reported with a significance of 4.0 standard deviations, resulting in the
measurement of
to
be .
Here denotes a branching fraction while and
are the production cross-sections for and mesons.
An indication of weak annihilation is found for the region
, with a significance of
2.4 standard deviations.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-022.html,
link to supplemental material inserted in the reference
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
Design and methods of a longitudinal study investigating the impact of antiretroviral treatment on the partnerships and sexual behaviour of HIV-infected individuals in rural KwaZulu-Natal, South Africa
BACKGROUND: Diagnosed HIV-infected people form an increasingly large sub-population in South Africa, one that will continue to grow with widely promoted HIV testing and greater availability of antiretroviral therapy (ART). For HIV prevention and support, understanding the impact of long-term ART on family and sexual relationships is a health research priority. This includes improving the availability of longitudinal demographic and health data on HIV-infected individuals who have accessed ART services but who are not yet ART-eligible.DESIGN AND METHODS: The aim of the study is to investigate the impact of ART on family and partner relationships, and sexual behaviour of HIV-infected individuals accessing a public HIV treatment and care programme in rural South Africa. HIV-infected men and women aged 18 years or older attending three clinics are screened. Those people initiating ART because they meet the criteria of WHO stage 4 or CD4 ? 200 cells/?L are assigned to an 'ART initiator' group. A 'Monitoring' group is composed of people whose most recent CD4 count was >500 cells/?L and are therefore, not yet eligible for ART. During the four-year study, data on both groups is collected every 6 months during clinic visits, or where necessary by home visits or phone. Detailed information is collected on social, demographic and health characteristics including living arrangements, past and current partnerships, sexual behaviour, HIV testing and disclosure, stigma, self-efficacy, quality of family and partner relationships, fertility and fertility intentions, ART knowledge and attitudes, and gender norms. Recruitment for both groups started in January 2009. As of October 2010, 600 participants have been enrolled; 386 in the ART initiator group (141, 37% male) and 214 in the Monitoring group (31, 14% male). Recruitment remains open for the Monitoring group.DISCUSSION: The data collected in this study will provide valuable information for measuring the impact of ART on sexual behaviour, and for the planning and delivery of appropriate interventions to promote family and partner support, and safe sexual behaviour for people living with HIV in this setting and elsewhere in sub-Saharan Africa
Effect of invader removal: pollinators stay but some native plants miss their new friend
Removal of invasive species often benefits
biological diversity allowing ecosystems’ recovery.
However, it is important to assess the functional roles
that invaders may have established in their new areas
to avoid unexpected results from species elimination.
Invasive animal-pollinated plants may affect the
plant–pollination interactions by changing pollinator
availability and/or behaviour in the community. Thus,
removal of an invasive plant may have important
effects on pollinator community that may then be
reflected positive or negatively on the reproductive
success of native plants. The objective of this study
was to assess the effect of removing Oxalis pescaprae,
an invasive weed widely spread in the
Mediterranean basin, on plant–pollinator interactions
and on the reproductive success of co-flowering native
plants. For this, a disturbed area in central Portugal,
where this species is highly abundant, was selected.
Visitation rates, natural pollen loads, pollen tube
growth and natural fruit set of native plants were
compared in the presence of O. pes-caprae and after
manual removal of their flowers. Our results showed a
highly resilient pollination network but also revealed
some facilitative effects of O. pes-caprae on the
reproductive success of co-flowering native plants.
Reproductive success of the native plants seems to
depend not only on the number and diversity of floral
visitors, but also on their efficiency as pollinators. The
information provided on the effects of invasive species
on the sexual reproductive success of natives is
essential for adequate management of invaded areas.This work is financed by FEDER funds through the
COMPETE Program and by Portuguese Foundation for Science
and Technology (FCT) funds in the ambit of the project PTDC/
BIA-BIC/110824/2009, by CRUP Acc¸o˜es Integradas Luso-
Espanholas 2010 with the project E10/10, by MCI-Programa de
Internacionalizacio´n de la I ? D (PT2009-0068) and by the
Spanish DGICYT (CGL2009-10466), FEDER funds from the
European Union, and the Xunta de Galicia (INCITE09-
3103009PR). FCT also supported the work of S. Castro (FCT/
BPD/41200/2007) and J. Costa (CB/C05/2009/209; PTDC/
BIA-BIC/110824/2009). The work of V. Ferrero was supported
by the Fundacio´n Ramo´n Areces
Factors Associated with Height Catch-Up and Catch-Down Growth Among Schoolchildren
In developed countries, children with intrauterine growth restriction (IUGR) or born preterm (PT) tend to achieve catch-up growth. There is little information about height catch-up in developing countries and about height catch-down in both developed and developing countries. We studied the effect of IUGR and PT birth on height catch-up and catch-down growth of children from two cohorts of liveborn singletons. Data from 1,463 children was collected at birth and at school age in Ribeirão Preto (RP), a more developed city, and in São Luís (SL), a less developed city. A change in z-score between schoolchild height z-score and birth length z-score≥0.67 was considered catch-up; a change in z-score≤−0.67 indicated catch-down growth. The explanatory variables were: appropriate weight for gestational age/PT birth in four categories: term children without IUGR (normal), IUGR only (term with IUGR), PT only (preterm without IUGR) and preterm with IUGR; infant's sex; maternal parity, age, schooling and marital status; occupation of family head; family income and neonatal ponderal index (PI). The risk ratio for catch-up and catch-down was estimated by multinomial logistic regression for each city. In RP, preterms without IUGR (RR = 4.13) and thin children (PI<10th percentile, RR = 14.39) had a higher risk of catch-down; catch-up was higher among terms with IUGR (RR = 5.53), preterms with IUGR (RR = 5.36) and children born to primiparous mothers (RR = 1.83). In SL, catch-down was higher among preterms without IUGR (RR = 5.19), girls (RR = 1.52) and children from low-income families (RR = 2.74); the lowest risk of catch-down (RR = 0.27) and the highest risk of catch-up (RR = 3.77) were observed among terms with IUGR. In both cities, terms with IUGR presented height catch-up growth whereas preterms with IUGR only had height catch-up growth in the more affluent setting. Preterms without IUGR presented height catch-down growth, suggesting that a better socioeconomic situation facilitates height catch-up and prevents height catch-down growth
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