2,551 research outputs found
Full Length Research Paper Isolation of protease producing novel Bacillus cereus and detection of optimal conditions
Fifteen bacterium strains were isolated from soil samples and the one that had the highest proteolytic activity, from Susano.lu village at Silifke-Mersin, was selected. The strain was identified and determined as Bacillus cereus. The bacterium, that had R type colony morphology, subterminal spores, motile and facultative anaerobe microorganism, was a gram positive with 10 ƒÊ length and 1 ƒÊ width. It could ferment glucose, fructose and maltose which formed acid but not gas. Catalase and urease were positive. The bacterium could grow on common medium easily and form b-haemolyze on blood agar. It was determined that the microorganismfs growth continued up to the 12th hour and when it gets to the 18th hour, it was in a stationary phase. As a result, after the 18th hour, it was in a lytic phase. The optimum growth temperature range was 20 - 40‹C and the optimum pH range was 6.0 . 10.0, respectively. Maximum growth was obtained at 30‹C and at pH 7.0. The highest protease activity was determined at 30‹C temperature and 6.4 pH conditions and after the 18th hour, it decreased evidently.Key words: Protease, production, optimization, Bacillus sp
Men as allies against sexism: The positive effects of a suggestion of sexism by male (vs. female) sources
Journal ArticleCopyright © 2014 the Author(s).Sexism is often expressed in subtle and ambiguous ways, causing targets to doubt their own capabilities or to show stereotypeconfirming behavior. This research examines whether the self-confidence and stereotype (dis-)confirming behavior of targets of sexism can be bolstered when other male versus female sources suggest that sexism may have played a role. Both Study 1 (N = 78) and Study 2 (N = 90) show that a suggestion of sexism has more beneficial effects when it is made by male sources than when it is made by female sources. When males suggested that sexism had taken place, targets reported more self-confidence (less self-handicapping and higher personal performance state self-esteem) and showed less stereotype confirmation (less self-stereotyping and better task performance) than when sexism was suggested by a female source. Study 2 additionally revealed that targets are more likely to file a complaint when men suggest that sexism took place than when this same suggestion was made by women. These results indicate that men can constitute important allies against sexism if they speak out when sexist treatment takes place
Responding to Gender-Based Rejection: Objecting Against Negative and Disproving Positive Intergroup Differentiation
Copyright © 2013 SAGE Publications. Author's draft version; post-print. Final version published by Sage available on Sage Journals Online http://online.sagepub.com/We examined whether women (N = 87) who are exposed to blatant discrimination show different responses depending on whether they are rejected with reference to positively (“this is something for men”) or negatively (“this is nothing for women”) phrased intergroup differentiation. Based on current insights on responses to discrimination, we predicted and found that those who are exposed to negative differentiation will tend to object to those who rejected them, while positive differentiation is more likely to induce efforts to disprove the validity of the rejection. Female participants facing negative differentiation objected against the discriminatory nature of their rejection and showed cardiovascular reactivity more indicative of threat (and less of challenge) than participants in the positive differentiation condition. In addition, positive differentiation caused participants to disprove the validity of these group-based expectations by claiming the possession of relatively more masculine (and less feminine) traits
Operational experience, improvements, and performance of the CDF Run II silicon vertex detector
The Collider Detector at Fermilab (CDF) pursues a broad physics program at
Fermilab's Tevatron collider. Between Run II commissioning in early 2001 and
the end of operations in September 2011, the Tevatron delivered 12 fb-1 of
integrated luminosity of p-pbar collisions at sqrt(s)=1.96 TeV. Many physics
analyses undertaken by CDF require heavy flavor tagging with large charged
particle tracking acceptance. To realize these goals, in 2001 CDF installed
eight layers of silicon microstrip detectors around its interaction region.
These detectors were designed for 2--5 years of operation, radiation doses up
to 2 Mrad (0.02 Gy), and were expected to be replaced in 2004. The sensors were
not replaced, and the Tevatron run was extended for several years beyond its
design, exposing the sensors and electronics to much higher radiation doses
than anticipated. In this paper we describe the operational challenges
encountered over the past 10 years of running the CDF silicon detectors, the
preventive measures undertaken, and the improvements made along the way to
ensure their optimal performance for collecting high quality physics data. In
addition, we describe the quantities and methods used to monitor radiation
damage in the sensors for optimal performance and summarize the detector
performance quantities important to CDF's physics program, including vertex
resolution, heavy flavor tagging, and silicon vertex trigger performance.Comment: Preprint accepted for publication in Nuclear Instruments and Methods
A (07/31/2013
Measurement of Dijet Angular Distributions at CDF
We have used 106 pb^-1 of data collected in proton-antiproton collisions at
sqrt(s)=1.8 TeV by the Collider Detector at Fermilab to measure jet angular
distributions in events with two jets in the final state. The angular
distributions agree with next to leading order (NLO) predictions of Quantum
Chromodynamics (QCD) in all dijet invariant mass regions. The data exclude at
95% confidence level (CL) a model of quark substructure in which only up and
down quarks are composite and the contact interaction scale is Lambda_ud(+) <
1.6 TeV or Lambda_ud(-) < 1.4 TeV. For a model in which all quarks are
composite the excluded regions are Lambda(+) < 1.8 TeV and Lambda(-) < 1. 6
TeV.Comment: 16 pages, 2 figures, 2 tables, LaTex, using epsf.sty. Submitted to
Physical Review Letters on September 17, 1996. Postscript file of full paper
available at http://www-cdf.fnal.gov/physics/pub96/cdf3773_dijet_angle_prl.p
Journal Staff
We present the first measurements of the differential cross section d sigma/dp(T)(gamma) for the production of an isolated photon in association with at least two b-quark jets. The measurements consider photons with rapidities vertical bar y(gamma)vertical bar < 1.0 and transverse momenta 30 < p(T)(gamma) < 200 GeV. The b-quark jets are required to have p(T)(jet) > 15 GeVand vertical bar y(jet)vertical bar < 1.5. The ratio of differential production cross sections for gamma + 2 b-jets to gamma + b-jet as a function of p(T)(gamma) is also presented. The results are based on the proton-antiproton collision data at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. The measured cross sections and their ratios are compared to the next- to- leading order perturbative QCD calculations as well as predictions based on the k(T)- factorization approach and those from the sherpa and pythia Monte Carlo event generators
Observation of Hadronic W Decays in t-tbar Events with the Collider Detector at Fermilab
We observe hadronic W decays in t-tbar -> W (-> l nu) + >= 4 jet events using
a 109 pb-1 data sample of p-pbar collisions at sqrt{s} = 1.8 TeV collected with
the Collider Detector at Fermilab (CDF). A peak in the dijet invariant mass
distribution is obtained that is consistent with W decay and inconsistent with
the background prediction by 3.3 standard deviations. From this peak we measure
the W mass to be 77.2 +- 4.6 (stat+syst) GeV/c^2. This result demonstrates the
presence of two W bosons in t-tbar candidates in the W (-> l nu) + >= 4 jet
channel.Comment: 20 pages, 4 figures, submitted to PR
Precise measurement of the top quark mass in the dilepton channel at D0
We measure the top quark mass (mt) in ppbar collisions at a center of mass
energy of 1.96 TeV using dilepton ttbar->W+bW-bbar->l+nubl-nubarbbar events,
where l denotes an electron, a muon, or a tau that decays leptonically. The
data correspond to an integrated luminosity of 5.4 fb-1 collected with the D0
detector at the Fermilab Tevatron Collider. We obtain mt = 174.0 +- 1.8(stat)
+- 2.4(syst) GeV, which is in agreement with the current world average mt =
173.3 +- 1.1 GeV. This is currently the most precise measurement of mt in the
dilepton channel.Comment: 7 pages, 4 figure
Measurements of single top quark production cross sections and |Vtb| in ppbar collisions at sqrt{s}=1.96 TeV
We present measurements of production cross sections of single top quarks in
\ppbar collisions at in a data sample corresponding
to an integrated luminosity of collected by the D0 detector
at the Fermilab Tevatron Collider. We select events with an isolated electron
or muon, an imbalance in transverse energy, and two, three, or four jets, with
one or two of them containing a bottom hadron. We obtain an inclusive cross
section of \sigma({\ppbar}{\rargap}tb+X, tqb+X) = 3.43\pm^{0.73}_{0.74}\;\rm
pb and use it to extract the CKM matrix element at
the 95% C.L. We also measure \sigma({\ppbar}{\rargap}tb+X) =
0.68\pm^{0.38}_{0.35}\;\rm pb and \sigma({\ppbar}{\rargap}tqb+X) =
2.86\pm^{0.69}_{0.63}\;\rm pb when assuming, respectively, and
production rates as predicted by the standard model.Comment: 11 pages, 8 figures, submitted to Phys. Rev.
Search for associated production in collisions at
This report describes a search for associated production of and Higgs
bosons based on data corresponding to an integrated luminosity of collected with the D0 detector at the Fermilab
Tevatron Collider. Events containing a
candidate (with corresponding to or ) are selected in
association with two or three reconstructed jets. One or two of the jets are
required to be consistent with having evolved from a quark. A multivariate
discriminant technique is used to improve the separation of signal and
backgrounds. Expected and observed upper limits are obtained for the product of
the production cross section and branching ratios and reported in terms of
ratios relative to the prediction of the standard model as a function of the
mass of the Higgs boson (). The observed and expected 95% C.L. upper
limits obtained for an assumed are, respectively, factors
of 4.5 and 4.8 larger than the value predicted by the standard model.Comment: 25 pages, 14 figure
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