A Neural Circuit Arbitrates between Persistence and Withdrawal in Hungry Drosophila.

In pursuit of food, hungry animals mobilize significant energy resources and overcome exhaustion and fear. How need and motivation control the decision to continue or change behavior is not understood. Using a single fly treadmill, we show that hungry flies persistently track a food odor and increase their effort over repeated trials in the absence of reward suggesting that need dominates negative experience. We further show that odor tracking is regulated by two mushroom body output neurons (MBONs) connecting the MB to the lateral horn. These MBONs, together with dopaminergic neurons and Dop1R2 signaling, control behavioral persistence. Conversely, an octopaminergic neuron, VPM4, which directly innervates one of the MBONs, acts as a brake on odor tracking by connecting feeding and olfaction. Together, our data suggest a function for the MB in internal state-dependent expression of behavior that can be suppressed by external inputs conveying a competing behavioral drive

Double hadron leptoproduction in the nuclear medium

First measurement of double-hadron production in deep-inelastic scattering has been measured with the HERMES spectrometer at HERA using a 27.6 GeV positron beam with deuterium, nitrogen, krypton and xenon targets. The influence of the nuclear medium on the ratio of double-hadron to single-hadron yields has been investigated. Nuclear effects are clearly observed but with substantially smaller magnitude and reduced $A$-dependence compared to previously measured single-hadron multiplicity ratios. The data are in fair agreement with models based on partonic or pre-hadronic energy loss, while they seem to rule out a pure absorptive treatment of the final state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter

Quark helicity distributions in the nucleon for up, down, and strange quarks from semi--inclusive deep--inelastic scattering

Polarized deep--inelastic scattering data on longitudinally polarized hydrogen and deuterium targets have been used to determine double spin asymmetries of cross sections. Inclusive and semi--inclusive asymmetries for the production of positive and negative pions from hydrogen were obtained in a re--analysis of previously published data. Inclusive and semi--inclusive asymmetries for the production of negative and positive pions and kaons were measured on a polarized deuterium target. The separate helicity densities for the up and down quarks and the anti--up, anti--down, and strange sea quarks were computed from these asymmetries in a ``leading order'' QCD analysis. The polarization of the up--quark is positive and that of the down--quark is negative. All extracted sea quark polarizations are consistent with zero, and the light quark sea helicity densities are flavor symmetric within the experimental uncertainties. First and second moments of the extracted quark helicity densities in the measured range are consistent with fits of inclusive data

Exclusive Leptoproduction of rho^0 Mesons from Hydrogen at Intermediate Virtual Photon Energies

Measurements of the cross section for exclusive virtual-photoproduction of rho^0 mesons from hydrogen are reported. The data were collected by the HERMES experiment using 27.5 GeV positrons incident on a hydrogen gas target in the HERA storage ring. The invariant mass W of the photon-nucleon system ranges from 4.0 to 6.0 GeV, while the negative squared four-momentum Q^2 of the virtual photon varies from 0.7 to 5.0 GeV^2. The present data together with most of the previous data at W > 4 GeV are well described by a model that infers the W-dependence of the cross section from the dependence on the Bjorken scaling variable x of the unpolarized structure function for deep-inelastic scattering. In addition, a model calculation based on Off-Forward Parton Distributions gives a fairly good account of the longitudinal component of the rho^0 production cross section for Q^2 > 2 GeV^2.Comment: 10 pages, 6 embedded figures, LaTeX for SVJour(epj) document class. Revisions: curves added to Fig. 1, several clarifications added to tex

Evidence for a narrow |S|=1 baryon state at a mass of 1528 MeV in quasi-real photoproduction

Evidence for a narrow baryon state is found in quasi-real photoproduction on a deuterium target through the decay channel p K^0_S --> p pi^+ pi^-. A peak is observed in the p K^0_S invariant mass spectrum at 1528 +/- 2.6 (stat) +/-2.1 (syst) MeV. Depending on the background model,the naive statistical significance of the peak is 4--6 standard deviations and its width may be somewhat larger than the experimental resolution of sigma=4.3 -- 6.2 MeV. This state may be interpreted as the predicted S=+1 exotic Theta^{+}(uuddbar(s)) pentaquark baryon. No signal for an hypothetical Theta^{++} baryon was observed in the pK^+ invariant mass distribution. The absence of such a signal indicates that an isotensor Theta is excluded and an isovector Theta is unlikely.Comment: 8 pages, 4 figure

Distribution of immunodeficiency fact files with XML – from Web to WAP

BACKGROUND: Although biomedical information is growing rapidly, it is difficult to find and retrieve validated data especially for rare hereditary diseases. There is an increased need for services capable of integrating and validating information as well as proving it in a logically organized structure. A XML-based language enables creation of open source databases for storage, maintenance and delivery for different platforms. METHODS: Here we present a new data model called fact file and an XML-based specification Inherited Disease Markup Language (IDML), that were developed to facilitate disease information integration, storage and exchange. The data model was applied to primary immunodeficiencies, but it can be used for any hereditary disease. Fact files integrate biomedical, genetic and clinical information related to hereditary diseases. RESULTS: IDML and fact files were used to build a comprehensive Web and WAP accessible knowledge base ImmunoDeficiency Resource (IDR) available at . A fact file is a user oriented user interface, which serves as a starting point to explore information on hereditary diseases. CONCLUSION: The IDML enables the seamless integration and presentation of genetic and disease information resources in the Internet. IDML can be used to build information services for all kinds of inherited diseases. The open source specification and related programs are available at

Signs of positive selection of somatic mutations in human cancers detected by EST sequence analysis

BACKGROUND: Carcinogenesis typically involves multiple somatic mutations in caretaker (DNA repair) and gatekeeper (tumor suppressors and oncogenes) genes. Analysis of mutation spectra of the tumor suppressor that is most commonly mutated in human cancers, p53, unexpectedly suggested that somatic evolution of the p53 gene during tumorigenesis is dominated by positive selection for gain of function. This conclusion is supported by accumulating experimental evidence of evolution of new functions of p53 in tumors. These findings prompted a genome-wide analysis of possible positive selection during tumor evolution. METHODS: A comprehensive analysis of probable somatic mutations in the sequences of Expressed Sequence Tags (ESTs) from malignant tumors and normal tissues was performed in order to access the prevalence of positive selection in cancer evolution. For each EST, the numbers of synonymous and non-synonymous substitutions were calculated. In order to identify genes with a signature of positive selection in cancers, these numbers were compared to: i) expected numbers and ii) the numbers for the respective genes in the ESTs from normal tissues. RESULTS: We identified 112 genes with a signature of positive selection in cancers, i.e., a significantly elevated ratio of non-synonymous to synonymous substitutions, in tumors as compared to 37 such genes in an approximately equal-sized EST collection from normal tissues. A substantial fraction of the tumor-specific positive-selection candidates have experimentally demonstrated or strongly predicted links to cancer. CONCLUSION: The results of EST analysis should be interpreted with extreme caution given the noise introduced by sequencing errors and undetected polymorphisms. Furthermore, an inherent limitation of EST analysis is that multiple mutations amenable to statistical analysis can be detected only in relatively highly expressed genes. Nevertheless, the present results suggest that positive selection might affect a substantial number of genes during tumorigenic somatic evolution

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Spin asymmetries A1 and structure functions g1 of the proton and the deuteron from polarized high energy muon scattering.

Adeva B, Akdogan T, Arik E, et al. Spin asymmetries A(1) and structure functions g(1) of the proton and the deuteron from polarized high energy muon scattering. Phys.Rev. D. 1998;58(11): 112001.We present the final results of the spin asymmetries A(1) and the spin structure functions g(1) of the proton and the deuteron in the kinematic range 0.0008 < x < 0.7 and 0.2 < Q(2) < 100 GeV2. For the determination of A(1), in addition to the usual method which employs inclusive scattering events and includes a large radiative background at low x, we use a new method which minimizes the radiative background by selecting events with at least one hadron as well as a muon in the final state. We find that this hadron method gives smaller errors for x < 0.02, so it is combined with the usual method to provide the optimal set of results. [S0556-2821(98)07017-9]