Mapping loci for chlorosis associated with chlorophyII b deficiency in potato

About 30% of the potato plants from a (Solanum tuberosum × S. berthaultii) × S. tuberosum backcross population had chlorotic, malformed leaves; but a gradation in symptom severity suggested regulation by more than one gene. The study was undertaken to determine whether this was the case, whether any genes previously reported to control chlorosis in potato were involved, and to see how symptoms were related to effects on chlorophyll content. Testing for quantitative trait loci indicated major control by a single recessive gene on chromosome 1, close to one or more loci that have been reported to produce chlorosis in tomato, but distinct from similar genes previously identified in potato. The proposed symbol for the potato gene that confers phenotype with chlorotic and malformed leaves is cml (chlorotic and malformed leaves). The effects of this gene appeared to be accentuated by a second gene, located on chromosome 12. Chlorotic plants showed a 50% decrease in chlorophyll b level in the affected parts of leaves. It is concluded that cml is different from previously reported genes for chlorosis in potato, that at least one other gene modifies the intensity of symptom expression, and that the observed chlorosis is produced through effects on chlorophyll b level

Sensing with FETs - once, now and future

In this paper a short overview is given of the several FET-based sensor devices and the operational principle of the ISFET is summarized. Some of the shortcomings of the FET sensors were circumvented by an alternative operational mode, resulting in a device capable of acid/base concentration determination by coulometric titrant generation as well as in an original pH-static enzyme sensor. A more recent example is presented in which the ISFET is used for the on-line monitoring of fermentation processes. Future research is directed towards direct covalent coupling of organic monolayers on the silicon itself. In addition, the field-effect can be applied to the so-called semiconducting nanowire devices, ultimately making single molecule detection of charged species possible

The ground state energy of the Edwards-Anderson spin glass model with a parallel tempering Monte Carlo algorithm

We study the efficiency of parallel tempering Monte Carlo technique for calculating true ground states of the Edwards-Anderson spin glass model. Bimodal and Gaussian bond distributions were considered in two and three-dimensional lattices. By a systematic analysis we find a simple formula to estimate the values of the parameters needed in the algorithm to find the GS with a fixed average probability. We also study the performance of the algorithm for single samples, quantifying the difference between samples where the GS is hard, or easy, to find. The GS energies we obtain are in good agreement with the values found in the literature. Our results show that the performance of the parallel tempering technique is comparable to more powerful heuristics developed to find the ground state of Ising spin glass systems.Comment: 30 pages, 17 figures. A new section added. Accepted for publication in Physica

Cerebral Perfusion and the Occurrence of Nonfocal Transient Neurological Attacks

INTRODUCTION: Nonfocal transient neurological attacks (TNAs) are associated with an increased risk of cardiac events, stroke and dementia. Their etiology is still unknown. Global cerebral hypoperfusion has been suggested to play a role in their etiology, but this has not been investigated. We assessed whether lower total brain perfusion is associated with a higher occurrence of TNAs. METHODS: Between 2015 and 2018, patients with heart failure were included in the Heart Brain Connection study. Patients underwent brain magnetic resonance imaging, including quantitative magnetic resonance angiography (QMRA) to measure cerebral blood flow (CBF). We calculated total brain perfusion of each participant by dividing total CBF by brain volume. Patients were interviewed with a standardized questionnaire on the occurrence of TNAs by physicians who were blinded to QMRA flow status. We assessed the relation between total brain perfusion and the occurrence of TNAs with Poisson regression analysis. RESULTS: Of 136 patients (mean age 70 years, 68% men), 29 (21%) experienced ≥1 TNAs. Nonrotatory dizziness was the most common subtype of TNA. Patients with TNAs were more often female and more often had angina pectoris than patients without TNAs, but total CBF and total brain perfusion were not different between both groups. Total brain perfusion was not associated with the occurrence of TNAs (adjusted risk ratio 1.12, 95% CI 0.88-1.42). CONCLUSION: We found no association between total brain perfusion and the occurrence of TNAs in patients with heart failure

Search for single top quarks in the tau+jets channel using 4.8 fb−1^{-1} of ppˉp\bar{p} collision data

We present the first direct search for single top quark production using tau leptons. The search is based on 4.8 fb$^{-1}$ of integrated luminosity collected in $p\bar{p}$ collisions at $\sqrt{s}$=1.96 TeV with the D0 detector at the Fermilab Tevatron Collider. We select events with a final state including an isolated tau lepton, missing transverse energy, two or three jets, one or two of them $b$ tagged. We use a multivariate technique to discriminate signal from background. The number of events observed in data in this final state is consistent with the signal plus background expectation. We set in the tau+jets channel an upper limit on the single top quark cross section of \TauLimObs pb at the 95% C.L. This measurement allows a gain of 4% in expected sensitivity for the observation of single top production when combining it with electron+jets and muon+jets channels already published by the D0 collaboration with 2.3 fb$^{-1}$ of data. We measure a combined cross section of \SuperCombineXSall pb, which is the most precise measurement to date.Comment: 12 pages, 5 figure

Measurement of Z/gamma*+jet+X angular distributions in ppbar collisions at sqrt{s}=1.96 TeV

We present the first measurements at a hadron collider of differential cross sections for Z+jet+X production in delta phi(Z, jet), |delta y(Z, jet)| and |y_boost(Z, jet)|. Vector boson production in association with jets is an excellent probe of QCD and constitutes the main background to many small cross section processes, such as associated Higgs production. These measurements are crucial tests of the predictions of perturbative QCD and current event generators, which have varied success in describing the data. Using these measurements as inputs in tuning event generators will increase the experimental sensitivity to rare signals.Comment: Published in Physics Letters B 682 (2010), pp. 370-380. 15 pages, 6 figure

Search for the standard model Higgs boson in tau final states

We present a search for the standard model Higgs boson using hadronically decaying tau leptons, in 1 inverse femtobarn of data collected with the D0 detector at the Fermilab Tevatron ppbar collider. We select two final states: tau plus missing transverse energy and b jets, and tau+ tau- plus jets. These final states are sensitive to a combination of associated W/Z boson plus Higgs boson, vector boson fusion and gluon-gluon fusion production processes. The observed ratio of the combined limit on the Higgs production cross section at the 95% C.L. to the standard model expectation is 29 for a Higgs boson mass of 115 GeV.Comment: publication versio

Search for a scalar or vector particle decaying into Zgamma in ppbar collisions at sqrt(s) = 1.96 TeV

We present a search for a narrow scalar or vector resonance decaying into Zgamma with a subsequent Z decay into a pair of electrons or muons. The data for this search were collected with the D0 detector at the Fermilab Tevatron ppbar collider at a center of mass energy sqrt(s) = 1.96 TeV. Using 1.1 (1.0) fb-1 of data, we observe 49 (50) candidate events in the electron (muon) channel, in good agreement with the standard model prediction. From the combination of both channels, we derive 95% C.L. upper limits on the cross section times branching fraction (sigma x B) into Zgamma. These limits range from 0.19 (0.20) pb for a scalar (vector) resonance mass of 600 GeV/c^2 to 2.5 (3.1) pb for a mass of 140 GeV/c^2.Comment: Published by Phys. Lett.

Search for the associated production of a b quark and a neutral supersymmetric Higgs boson which decays to tau pairs

We report results from a search for production of a neutral Higgs boson in association with a $b$ quark. We search for Higgs decays to $\tau$ pairs with one $\tau$ subsequently decaying to a muon and the other to hadrons. The data correspond to 2.7fb$^{-1}$ of \ppbar collisions recorded by the D0 detector at $\sqrt{s} = 1.96$TeV. The data are found to be consistent with background predictions. The result allows us to exclude a significant region of parameter space of the minimal supersymmetric model.Comment: Submitted to Phys. Rev. Letter

Search for charged Higgs bosons in top quark decays

We present a search for charged Higgs bosons in top quark decays. We analyze the \eplus, \muplus, $ee$, $e\mu$, $\mu\mu$, \etau and \mutau final states from top quark pair production events, using data from about 1${\text{fb}}^{-1}$ of integrated luminosity recorded by the \dzero experiment at the Fermilab Tevatron Collider. We consider different scenarios of possible charged Higgs boson decays, one where the charged Higgs boson decays purely hadronically into a charm and a strange quark, another where it decays into a $\tau$ lepton and a $\tau$ neutrino and a third one where both decays appear. We extract limits on the branching ratio $B(t\to H^+ b)$ for all these models. We use two methods, one where the $t\bar{t}$ production cross section is fixed, and one where the cross section is fitted simultaneously with $B(t\to H^+b)$. Based on the extracted limits, we exclude regions in the charged Higgs boson mass and $\tan \beta$ parameter space for different scenarios of the minimal supersymmetric standard model.Comment: 10 pages, 8 figures, submitted to PL