2,531 research outputs found

    Characterization of Aspergillus Flavus Soil and Corn Kernel Populations From Eight Mississippi River States

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    Aspergillus flavus is a saprophytic ascomycete that can also actively invade the seed of crops and potentially contaminate them with harmful aflatoxins. Management of A. flavus currently relies mostly on biocontrol. However, there is still a lot to learn about its biology and ecology so the current approach can be improved. An A. flavus population survey was undertaken during the fall of 2014 across eight Mississippi River states to determine population diversity and geographic distribution of VCGs. Isolates from corn and soil were also characterized for VCG, sclerotial morphotype, mating type, cyclopiazonic acid, and aflatoxin production in order to determine trait uniformity within VCGs and those VCGs traits which may be associated with corn infection. From a collection of 339 soil and 204 kernel isolates, 18 multiple-isolate VCGs were determined. Four VCGs accounted for 54% of soil and 48% of total kernel populations and these were the only ones recovered from both niches. Nine VCGs were only recovered from the soil population and 5 from corn kernels. Two VCGs were widely distributed across the 8-state transect and they were the same most frequently isolated from corn kernels in Louisiana in 2007. Results also indicate that the A. flavus metapopulation along the Mississippi River was highly genetically diverse as reflected by the diversity of VCGs. Southern populations were more diverse, and the northern region showed higher clonal fractions. Mating type MAT1-2 and high CPA production were associated with corn infectors, which were mainly of the L-morphotype. The soil niche had both, S and L-sclerotial morphotypes and although ~70% of isolates from both niches produced CPA, kernel isolates produced higher concentrations and support the report that CPA is a pathogenicity factor for A. flavus. These results give insight into important traits for corn infection, for both toxigenic and atoxigenic strains, which may be key in the improvement of biological control strategies. Characterizing the diversity of VCGs and their distribution over a 1500 km transect spanning important corn growing areas in the US, has allowed creation of a quantitative baseline of VCGs which can be used for monitoring changes in biodiversity over time

    TBL1 is required for the mesenchymal phenotype of transformed breast cancer cells

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    The epithelial-to-mesenchymal transition (EMT) and its reversion (MET) are related to tumor cell dissemination and migration, tumor circulating cell generation, cancer stem cells, chemoresistance, and metastasis formation. To identify chromatin and epigenetic factors possibly involved in the process of EMT, we compare the levels of expression of epigenetic genes in a transformed human breast epithelial cell line (HMEC-RAS) versus a stable clone of the same cell line expressing the EMT master regulator ZEB1 (HMEC-RAS-ZEB1). One of the factors strongly induced in the HMEC-RAS-ZEB1 cells was Transducin beta-like 1 (TBL1), a component of the NCoR complex, which has both corepressor and coactivator activities. We show that TBL1 interacts with ZEB1 and that both factors cooperate to repress the promoter of the epithelial gene E-cadherin (CDH1) and to autoactivate the ZEB1 promoter. Consistent with its central role, TBL1 is required for mesenchymal phenotypes of transformed breast epithelial and breast cancer cell lines of the claudin-low subtype. Importantly, a high expression of the TBL1 gene correlates with poor prognosis and increased proportion of metastasis in breast cancer patients, indicating that the level of TBL1 expression can be used as a prognostic marker.Ministerio de Economía y Competitividad BFU2014-53543-P, BFU2017-85420-RJunta de Andalucía BIO-32

    WMR Kinematic Control Using Underactuated Mechanisms for Goal Direction and Evasion

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    This work presents the mechanical design and the kinematic navigation control system for a tricycle-wheeled robot (one drive-steer and two lateral fixed passive) with two underactuated mechanisms: a global compass and local evasive compass. The proposed goal-reference mechanism is inspired by the ancient Chinese south-seeking chariot (c. 200–265 CE) used as a navigation compass. The passive lateral wheels transmit an absolute angle from its differential speeds to automatically steer the front wheel. An obstacle-evasive compass mechanism is commutated for steering control when detecting nearby obstacles. The absolute and local compass mechanisms commutate each other to control to the robot’s steering wheel to reach a goal while avoiding collisions. A kinematic control law is described in terms of the robot’s geometric constraints and is combined with a set of first-order partial derivatives that allows interaction between the global and local steering mechanisms. Animated simulations and numerical computations about the robot’s mechanisms and trajectories in multi-obstacle scenarios validate the proposed kinematic control system and its feasibility

    New record of Pachyarmatherium (Cingulata: Pachyarmatheriidae) from the Late Pleistocene in Venezuela

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    The Falcón state, in northwestern Venezuela, preserves one of the oldest localities documenting human presence on the Americas in association with megafauna remains. One of these localities is the Late Pleistocene Taima-Taima site, which is located in the vicinity of the Caribbean coast. Excavations since the 1960s in the Taima-Taima site, and surroundings, have offered new insights into the faunal assemblages that inhabited this arid coastal savannah region during the Late Pleistocene. Isolated osteoderms collected in recent prospections allow us to report here the presence of the extinct cingulate Pachyarmatherium cf. brasiliense and Pachyarmatherium sp. from the Taima-Taima site, and the new locality Cucuruchú (Las Dunas). The record of these taxa in the Late Pleistocene of the Falcón state increases the known paleodiversity of Cingulata for the region and expands the geographical distribution of the genus, which is poorly known in South America

    Preferences in ‘Jalapeño’ pepper attributes: a choice study in Mexico

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    Background: According to Mexican growers of ‘Jalapeño’ peppers, its commercialization is the primary limitation. Thus, consumer knowledge is critical to develop added-value strategies. The objective of this study was to identify ‘Jalapeño’ quality attributes to determine consumer preferences and willingness to pay, based on socioeconomic characteristics. Methods: A nationwide face-to-face survey was carried out using the discrete choice experiment method. The survey included 1200 consumers stratified by gender, age and region. Results: Heterogeneity analysis using the probabilistic segmentation model revealed three types of consumers: A price-sensitive segment, non-demanding consumers without specific preferences and selective consumers with a preference shifted toward specific ‘Jalapeño’ characteristics. Thus, detail-oriented producers must compete through price strategies, based on the marketplace (markets on wheels, grocery stores, or supermarkets) and through some quality attributes preferred by selective consumers. Therefore, results suggest that farmers should grow the correct varieties with appropriate agronomic management to cope consumer preferences. Conclusions: This paper contributes to the growing body of the ‘Jalapeño’ literature by explicitly investigating consumer preferences and willingness to pay for them.Postprint (published version

    Search for high-mass resonances decaying to a jet and a Lorentz-boosted resonance in proton-proton collisions at √s = 13 TeV

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    A search is reported for high-mass hadronic resonances that decay to a parton and a Lorentz-boosted resonance, which in turn decays into a pair of partons. The search is based on data collected with the CMS detector at the LHC in proton-proton collisions at √s = 13TeV, corresponding to an integrated luminosity of 138fb−1. The boosted resonance is reconstructed as a single wide jet with substructure consistent with a two-body decay. The high-mass resonance is thus considered as a dijet system. The jet substructure information and the kinematic properties of cascade resonance decays are exploited to disentangle the signal from the large quantum chromodynamics multijet background. The dijet mass spectrum is analyzed for the presence of new high-mass resonances, and is found to be consistent with the standard model background predictions. Results are interpreted in a warped extra dimension model where the high-mass resonance is a Kaluza–Klein gluon, the boosted resonance is a radion, and the final state partons are all gluons. Limits on the production cross section are set as a function of the Kaluza–Klein gluon and radion masses. These limits exclude at 95% confidence level models with Kaluza–Klein gluon masses in the range 2.0 to 4.3 TeV and radion masses in the range 0.20 to 0.74 TeV. By exploring a novel experimental signature, the observed limits on the Kaluza–Klein gluon mass are extended by up to about 1 TeV compared to previous searche

    Search for long-lived particles decaying in the CMS end cap muon detectors in proton-proton collisions at √s = 13 TeV

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    Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMA search for long-lived particles (LLPs) produced in decays of standard model (SM) Higgs bosons is presented. The data sample consists of 137 fb−1 of proton-proton collisions at √s p = 13 TeV, recorded at the LHC in 2016–2018. A novel technique is employed to reconstruct decays of LLPs in the end cap muon detectors. The search is sensitive to a broad range of LLP decay modes and to masses as low as a few GeV. No excess of events above the SM background is observed. The most stringent limits to date on the branching fraction of the Higgs boson to LLPs subsequently decaying to quarks and ꞇ+ꞇ− are found for proper decay lengths greater than 6, 20, and 40 m, for LLP masses of 7, 15, and 40 GeV, respectivel

    Measurement of the production cross section for Z + b jets in proton-proton collisions at √s = 13 TeV

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    Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMThe measurement of the cross section for the production of a Z boson, decaying to dielectrons or dimuons, in association with at least one bottom quark jet is performed with proton-proton collision data at The measurement of the cross section for the production of a Z boson, decaying to dielectrons or dimuons, in association with at least one bottom quark jet is performed with proton-proton collision data at √s=13 TeV. The data sample corresponds to an integrated luminosity of 137 fb-1, collected by the CMS experiment at the LHC during 2016-2018. The integrated cross sections for Z+≥1 b jet and Z+≥2 b jets are reported for the electron, muon, and combined channels. The fiducial cross sections in the combined channel are 6.52 ± 0.04(stat) ± 0.40(syst) ± 0.14(theo) pb for Z+ ≥ 1 b jet and 0.65±0.03(stat) ± 0.07(syst)± 0.02(theo) pb for Z+ ≥ 2 b jets. The differential cross section distributions are measured as functions of various kinematic observables that are useful for precision tests of perturbative quantum chromodynamics predictions. The ratios of integrated and differential cross sections for Z+≥2b jets and Z+≥1 b jet processes are also determined. The value of the integrated cross section ratio measured in the combined channel is 0.100 ± 0.005(stat) ± 0.007(syst) ± 0.003(theo). All measurements are compared with predictions from various event generators.s = 13 TeV. The data sample corresponds to an integrated luminosity of 137 fb-1, collected by the CMS experiment at the LHC during 2016-2018. The integrated cross sections for Z+≥1 b jet and Z+≥2 b jets are reported for the electron, muon, and combined channels. The fiducial cross sections in the combined channel are 6.52±0.04(stat)±0.40(syst)±0.14(theo) pb for Z+ ≥ 1 b jet and 0.65±0.03(stat) ± 0.07(syst) ± 0.02(theo) pb for Z+ ≥ 2 b jets. The differential cross section distributions are measured as functions of various kinematic observables that are useful for precision tests of perturbative quantum chromodynamics predictions. The ratios of integrated and differential cross sections for Z+ ≥ 2b jets and Z+ ≥ 1 b jet processes are also determined. The value of the integrated cross section ratio measured in the combined channel is 0.100 ± 0.005(stat) ± 0.007(syst) ± 0.003(theo). All measurements are compared with predictions from various event generator
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