168 research outputs found
Future Fitness of Female Insect Pests in Temporally Stable and Unstable Habitats and Its Impact on Habitat Utility as Refuges for Insect Resistance Management
The long-term fitness of individuals is examined in complex and temporally dynamic ecosystems. We call this multigeneration fitness measure âfuture fitnessâ. Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) is a polyphagous insect that feeds on many wild and cultivated hosts. While four generations of H. zea occur during the cropping season in the U.S. Mid Southern agroecosysem, the latter two generations were of most interest, as corn (which has been largely nontransgenic in the Mid-South) dominates the first two generations in the cropping system. In simulations of the evolution of resistance to Bt-transgenic crops, cotton refuge areas were found to be significantly more effective than similar soybean acreages at delaying the evolution of resistance. Cotton is a suitable host for H. zea during two late summer generations, while a soybean field is suitable for only one of these generations, therefore soybean fields of other maturity groups were simulated as being attractive during the alternative generation. A hypothetical soybean variety was tested in which a single field would be attractive over both generations and it was found to be significantly more effective at delaying resistance than simulated conventional soybean varieties. Finally, the placement of individuals emerging at the start of the 3rd (first without corn) generation was simulated in either refuge cotton, conventional soybean and the hypothetical long attractive soybean and the mean number of offspring produced was measured at the end of the season. Although females in conventional and long soybean crops had the same expected fecundity, because of differences in temporal stability of the two crops, the long soybean simulations had significantly more H. zea individuals at the end of the season than the conventional soybean simulations. These simulations demonstrate that the long-term fecundity associated with an individual is dependent not only on the fecundity of that individual in its current habitat, but also the temporal stability of habitats, the ecosystem at large and the likelihood that the individual's offspring will move into different habitats
First observations of separated atmospheric nu_mu and bar{nu-mu} events in the MINOS detector
The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of nu” and [overline nu ]” charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving Rup/downdata/Rup/downMC=0.62-0.14+0.19(stat.)±0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field nu” and [overline nu ]” interactions are separated. The ratio of [overline nu ]” to nu” events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R[overline nu ][sub mu]/nu[sub mu]data/R[overline nu ][sub mu]/nu[sub mu]MC=0.96-0.27+0.38(stat.)±0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for nu” and [overline nu ]”
Robust Antigen Specific Th17 T Cell Response to Group A Streptococcus Is Dependent on IL-6 and Intranasal Route of Infection
Group A streptococcus (GAS, Streptococcus pyogenes) is the cause of a variety of clinical conditions, ranging from pharyngitis to autoimmune disease. Peptide-major histocompatibility complex class II (pMHCII) tetramers have recently emerged as a highly sensitive means to quantify pMHCII-specific CD4+ helper T cells and evaluate their contribution to both protective immunity and autoimmune complications induced by specific bacterial pathogens. In lieu of identifying an immunodominant peptide expressed by GAS, a surrogate peptide (2W) was fused to the highly expressed M1 protein on the surface of GAS to allow in-depth analysis of the CD4+ helper T cell response in C57BL/6 mice that express the I-Ab MHCII molecule. Following intranasal inoculation with GAS-2W, antigen-experienced 2W:I-Ab-specific CD4+ T cells were identified in the nasal-associated lymphoid tissue (NALT) that produced IL-17A or IL-17A and IFN-Îł if infection was recurrent. The dominant Th17 response was also dependent on the intranasal route of inoculation; intravenous or subcutaneous inoculations produced primarily IFN-Îł+ 2W:I-Ab+ CD4+ T cells. The acquisition of IL-17A production by 2W:I-Ab-specific T cells and the capacity of mice to survive infection depended on the innate cytokine IL-6. IL-6-deficient mice that survived infection became long-term carriers despite the presence of abundant IFN-Îł-producing 2W:I-Ab-specific CD4+ T cells. Our results suggest that an imbalance between IL-17- and IFN-Îł-producing CD4+ T cells could contribute to GAS carriage in humans
Working conditions and public health risks in slaughterhouses in western Kenya
Background: Inadequate facilities and hygiene at slaughterhouses can result in contamination of meat and
occupational hazards to workers. The objectives of this study were to assess current conditions in slaughterhouses
in western Kenya and the knowledge, and practices of the slaughterhouse workers toward hygiene and sanitation.
Methods: Between February and October 2012 all consenting slaughterhouses in the study area were recruited.
A standardised questionnaire relating to facilities and practices in the slaughterhouse was administered to the
foreperson at each site. A second questionnaire was used to capture individual slaughterhouse workersâ knowledge,
practices and recent health events.
Results: A total of 738 slaughterhouse workers from 142 slaughterhouses completed questionnaires. Many
slaughterhouses had poor infrastructure, 65% (95% CI 63â67%) had a roof, cement floor and walls, 60%
(95% CI 57â62%) had a toilet and 20% (95% CI 18â22%) had hand-washing facilities. The meat inspector
visited 90% (95% CI 92â95%) of slaughterhouses but antemortem inspection was practiced at only 7% (95% CI 6â8%).
Nine percent (95% CI 7â10%) of slaughterhouses slaughtered sick animals. Only half of workers wore personal
protective clothing - 53% (95% CI 51â55%) wore protective coats and 49% (95% CI 46â51%) wore rubber boots.
Knowledge of zoonotic disease was low with only 31% (95% CI 29â33%) of workers aware that disease could be
transmitted from animals.
Conclusions: The current working conditions in slaughterhouses in western Kenya are not in line with the
recommendations of the Meat Control Act of Kenya. Current facilities and practices may increase occupational
exposure to disease or injury and contaminated meat may enter the consumer market. The findings of this study
could enable the development of appropriate interventions to minimise public health risks. Initially,
improvements need to be made to facilities and practices to improve worker safety and reduce the risk of food
contamination. Simultaneously, training programmes should target workers and inspectors to improve awareness
of the risks. In addition, education of health care workers should highlight the increased risks of injury and
disease in slaughterhouse workers. Finally, enhanced surveillance, targeting slaughterhouse workers could be
used to detect disease outbreaks. This âOne Healthâ approach to disease surveillance is likely to benefit workers,
producers and consumers
Bradyrhizobium elkanii nod regulon: insights through genomic analysis
Abstract A successful symbiotic relationship between soybean [Glycine max (L.) Merr.] and Bradyrhizobium species requires expression of the bacterial structural nod genes that encode for the synthesis of lipochitooligosaccharide nodulation signal molecules, known as Nod factors (NFs). Bradyrhizobium diazoefficiens USDA 110 possesses a wide nodulation gene repertoire that allows NF assembly and modification, with transcription of the nodYABCSUIJnolMNOnodZ operon depending upon specific activators, i.e., products of regulatory nod genes that are responsive to signaling molecules such as flavonoid compounds exuded by host plant roots. Central to this regulatory circuit of nod gene expression are NodD proteins, members of the LysR-type regulator family. In this study, publicly available Bradyrhizobium elkanii sequenced genomes were compared with the closely related B. diazoefficiens USDA 110 reference genome to determine the similarities between those genomes, especially with regards to the nod operon and nod regulon. Bioinformatics analyses revealed a correlation between functional mechanisms and key elements that play an essential role in the regulation of nod gene expression. These analyses also revealed new genomic features that had not been clearly explored before, some of which were unique for some B. elkanii genomes
LeMMINGs - I. The eMERLIN legacy survey of nearby galaxies. 1.5-GHz parsec-scale radio structures and cores
We present the first data release of high-resolution ( arcsec)
1.5-GHz radio images of 103 nearby galaxies from the Palomar sample, observed
with the eMERLIN array, as part of the LeMMINGs survey. This sample includes
galaxies which are active (LINER and Seyfert) and quiescent (HII galaxies and
Absorption line galaxies, ALG), which are reclassified based upon revised
emission-line diagrams. We detect radio emission 0.2 mJy for 47/103
galaxies (22/34 for LINERS, 4/4 for Seyferts, 16/51 for HII galaxies and 5/14
for ALGs) with radio sizes typically of 100 pc. We identify the radio
core position within the radio structures for 41 sources. Half of the sample
shows jetted morphologies. The remaining half shows single radio cores or
complex morphologies. LINERs show radio structures more core-brightened than
Seyferts. Radio luminosities of the sample range from 10 to 10
erg s: LINERs and HII galaxies show the highest and the lowest radio
powers respectively, while ALGs and Seyferts have intermediate luminosities. We
find that radio core luminosities correlate with black hole (BH) mass down to
10 M, but a break emerges at lower masses. Using [O III]
line luminosity as a proxy for the accretion luminosity, active nuclei and
jetted HII galaxies follow an optical fundamental plane of BH activity,
suggesting a common disc-jet relationship. In conclusion, LINER nuclei are the
scaled-down version of FR I radio galaxies; Seyferts show less collimated jets;
HII galaxies may host weak active BHs and/or nuclear star-forming cores; and
recurrent BH activity may account for ALG properties
LeMMINGs - II. The e-MERLIN legacy survey of nearby galaxies. The deepest radio view of the Palomar sample on parsec scale
We present the second data release of high-resolution ( arcsec)
1.5-GHz radio images of 177 nearby galaxies from the Palomar sample, observed
with the e-MERLIN array, as part of the LeMMINGs (Legacy e-MERLIN Multi-band
Imaging of Nearby Galaxy Sample) survey. Together with the 103 targets of the
first LeMMINGs data release, this represents a complete sample of 280 local
active (LINER and Seyfert) and inactive galaxies HII galaxies and Absorption
Line Galaxies, ALG). This large program is the deepest radio survey of the
local Universe, 10 W Hz, regardless of the host and
nuclear type: we detect radio emission 0.25 mJy beam for
125/280 galaxies (44.6 per cent) with sizes of typically 100 pc. Of
those 125, 106 targets show a core which coincides within 1.2 arcsec with the
optical nucleus. Although we observed mostly cores, around one third of the
detected galaxies features jetted morphologies. The detected radio core
luminosities of the sample range between 10 and 10 erg
s. LINERs and Seyferts are the most luminous sources, whereas HII
galaxies are the least. LINERs show FRI-like core-brightened radio structures,
while Seyferts reveal the highest fraction of symmetric morphologies. The
majority of HII galaxies have single radio core or complex extended structures,
which probably conceal a nuclear starburst and/or a weak active nucleus (seven
of them show clear jets). ALGs, which are typically found in evolved
ellipticals, although the least numerous, exhibit on average the most luminous
radio structures, similar to LINERs
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