966 research outputs found

    Two-Photon Doppler cooling of alkaline-earth-metal and ytterbium atoms

    Full text link
    A new possibility of laser cooling of alkaline-earth-metal and Ytterbium atoms using a two-photon transition is analyzed. We consider a 1S0^{1}S_{0} - 1S0^{1}S_{0} transition, with excitation in near resonance with the 1P1^{1}P_{1} level. This greatly increases the two-photon transition rate, allowing an effective transfer of momentum. The experimental implementation of this technique is discussed and we show that for Calcium, for example, two-photon cooling can be used to achieve a Doppler limit of 123 microKelvin. The efficiency of this cooling scheme and the main loss mechanisms are analyzed.Comment: 7 pages, 5 figure

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

    Get PDF
    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Behavioral Analysis Of Malicious Code Through Network Traffic And System Call Monitoring

    Get PDF
    Malicious code (malware) that spreads through the Internet-such as viruses, worms and trojans-is a major threat to information security nowadays and a profitable business for criminals. There are several approaches to analyze malware by monitoring its actions while it is running in a controlled environment, which helps to identify malicious behaviors. In this article we propose a tool to analyze malware behavior in a non-intrusive and effective way, extending the analysis possibilities to cover malware samples that bypass current approaches and also fixes some issues with these approaches. © 2011 SPIE.8059The Society of Photo-Optical Instrumentation Engineers (SPIE)Balzarotti, D., Cova, M., Karlberger, C., Kruegel, C., Kirda, E., Vigna, G., Efficient detection of split personalities in malware (2010) 17th Annual Network and Distributed System Security SymposiumBayer, U., Habibi, I., Balzarotti, D., Kirda, E., Kruegel, C., A view on current malware behaviors (2009) Usenix Workshop on Large-scale Exploits and Emergent Threats (LEET)Bayer, U., Kruegel, C., Kirda, E., TTanalyze: A tool for analyzing malware (2006) Proc. 15th Ann. Conf. European Inst. for Computer Antivirus Research (EICAR), pp. 180-192Bellard, F., QEMU, a fast and portable dynamic translator (2005) Proc. of the Annual Conference on USENIX Annual Technical Conference, pp. 41-41. , USENIX AssociationBinsalleeh, H., Ormerod, T., Boukhtouta, A., Sinha, P., Youssef, A., Debbabi, M., Wang, L., On the analysis of the zeus botnet crimeware toolkit (2010) Proc. of the Eighth Annual Conference on Privacy, Security and Trust, PST'2010Blunden, B., (2009) The Rootkit Arsenal: Escape and Evasion in the Dark Corners of the System, , Jones and Bartlett Publishers, Inc, 1th editionChoi, Y., Kim, I., Oh, J., Ryou, J., PE file header analysis-based packed pe file detection technique (PHAD) (2008) Proc of the International Symposium on Computer Science and Its Applications, pp. 28-31Dinaburg, A., Royal, P., Sharif, M., Lee, W., Ether: Malware analysis via hardware virtualization extensions (2008) Proc. Proceedings of the 15th ACM Conference on Computer and Communications Security (CCS 2008), , OctoberFather, H., Hooking windows API-technics of hooking API functions on windows (2004) CodeBreakers J., 1 (2)Franklin, J., Paxson, V., Perrig, A., Savage, S., An inquiry into the nature and causes of the wealth of internet miscreants (2007) Conference on Computer and Communications Security (CCS)Garfinkel, T., Rosenblum, M., A virtual machine introspection based architecture for intrusion detection (2003) Proc. Network and Distributed Systems Security Symposium, pp. 191-206Hoglund, G., Butler, J., (2005) Rootkits: Subverting the Windows Kernel, , Addison- Wesley Professional, 1th editionHolz, T., Engelberth, M., Freiling, F., Learning more about the underground economy: A case-study of keyloggers and dropzones (2008) Reihe Informatik TR-2008-006, , University of Mannheimhttp://www.joebox.org/Kang, M.G., Poosankam, P., Yin, H., Renovo: A hidden code extractor for packed exe-cutables (2007) Proc. of the 2007 ACM Workshop on Recurring Malcode (WORM 2007)Kong, J., (2007) Designing BSD Rootkits, , No Starch Press, 1th editionLeder, F., Werner, T., Know your enemy: Containing conficker (2009) The Honeynet Project & Research AllianceMartignoni, L., Christodorescu, M., Jha, S., Omniunpack: Fast, generic, and safe unpack-ing of malware (2007) Proc. of the Annual Computer Security Applications Conference (ACSAC)http://download.microsoft.com/download/9/c/5/9c5b2167-8017-4bae-9fde- d599bac8184a/pecoff_v8.docxMoser, A., Kruegel, C., Kirda, E., Limits of static analysis for malware detection (2007) ACSAC, pp. 421-430. , IEEE Computer Societyhttp://www.securelist.com/en/descriptions/old145521http://www.softpanorama.org/Malware/Malware_defense_history/ Malware_gallery/Network_worms/allaple_rahack.shtmlSong, D., Brumley, D., Yin, H., Caballero, J., Jager, I., Kang, M.G., Liang, Z., Saxena, P., BitBlaze: A new approach to computer security via binary analysis (2008) Proc. of the 4th International Conference on Information Systems SecurityWillems, G., Holz, T., Freiling, F., Toward automated dynamic malware analysis using CWSandbox (2007) IEEE Security and Privacy, 5 (2), pp. 32-39. , DOI 10.1109/MSP.2007.45Yegneswaran, V., Saidi, H., Porras, P., Eureka: A framework for enabling static analysis on malware (2008) Technical Report SRI-CSL-08-01 Computer Science Laboratory and College of Computing, , Georgia Institute of Technolog

    Measurement of charm production at central rapidity in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV

    Get PDF
    The pTp_{\rm T}-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D0^0, D+^+, and D+^{*+} in the rapidity range y<0.5|y|<0.5, and for transverse momentum 1<pT<121< p_{\rm T} <12 GeV/cc, were measured in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D0^0 \rightarrow Kπ\pi, D+^+ \rightarrow Kππ\pi\pi, D+^{*+} \rightarrow D0π^0\pi, and their charge conjugates, and was performed on a Lint=1.1L_{\rm int} = 1.1 nb1^{-1} event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at s=2.76\sqrt{s} = 2.76 TeV and at 7 TeV was evaluated by extrapolating to the full phase space the pTp_{\rm T}-differential production cross sections at s=2.76\sqrt{s} = 2.76 TeV and our previous measurements at s=7\sqrt{s} = 7 TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/307

    Particle-yield modification in jet-like azimuthal di-hadron correlations in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

    Get PDF
    The yield of charged particles associated with high-pTp_{\rm T} trigger particles (8<pT<158 < p_{\rm T} < 15 GeV/cc) is measured with the ALICE detector in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV relative to proton-proton collisions at the same energy. The conditional per-trigger yields are extracted from the narrow jet-like correlation peaks in azimuthal di-hadron correlations. In the 5% most central collisions, we observe that the yield of associated charged particles with transverse momenta pT>3p_{\rm T}> 3 GeV/cc on the away-side drops to about 60% of that observed in pp collisions, while on the near-side a moderate enhancement of 20-30% is found.Comment: 15 pages, 2 captioned figures, 1 table, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/350

    Use of Cellulosic Materials as Dye Adsorbents — A Prospective Study

    Get PDF
    Cellulose is the most abundant biopolymer of nature, and it is widely used in the synthesis of new materials as well as in the adsorption of dye. This study reports a literature review (articles) and technology review (patents) about publications and product invention, which contain information on the use of cellulose on the adsorption of dyes in the period 2004–2014. For this work, research database and keywords were used to find articles and patents related to the subject under review. Specific words were used to find articles and patents related to the subject under review. After a demanding research, 1 patent and 23 articles that contain the words “cellulose,” “dye,” and “adsorption or sorption” in their titles were assessed, and annual evolution studies were performed for publications and countries that publish more

    Chemical Functionalization of Cellulosic Materials — Main Reactions and Applications in the Contaminants Removal of Aqueous Medium

    Get PDF
    The cellulose is the most abundant biopolymer in the world and presents a higher chemical variability for presence of several hydroxyl groups. These hydroxyl groups allow surface modification of biomaterials, with insertion of several chemical groups which change cellulose characteristics. This natural biopolymer and its derivatives have been used a lot as adsorbent, from several contaminants of aqueous medium due to biocompatibility, chemical degradability, and variability. Therefore, this chapter has the objective to review the literature about several cellulose surfaces or cellulosic material (incorporation of carboxymethyl, phosphorus, carboxyl, amines, and sulfur), presenting the main characteristics of reactions and showing its adsorption in application of aqueous medium (metals, dyes, and drugs), locating the main interactions between biomaterial/contaminant

    Ictiofauna Dos Enclaves De Floresta úmida Nos Planaltos Da Ibiapaba E Do Araripe, Nordeste Do Brasil

    Get PDF
    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Humid highland forest enclaves are remnants of Atlantic Forest found in tablelands within the Caatinga biome (Northeastern Brazil), which emerged during interglacial periods in the Pleistocene. These ecosystems have a highly diverse and endemic fish fauna. Most earlier surveys have focused on the tableland of Borborema (Pernambuco and Paraíba States). In this study we surveyed the fish fauna of the humid forest enclaves in the tablelands of Ibiapaba and Araripe, based on samples collected in the rainy season (March and April) between 2009 and 2014. The 45 sampling points covered rivers, streams and reservoirs in five river basins belonging to three ecoregions. The species were listed according to drainage divide, and endemism was determined for each ecoregion and for the Caatinga. Our area was more species-rich (n=59) than Borborema (n=27). The samples included five introduced species and 29 species endemic to the Caatinga (49.1% of the sampled species). The distribution of Parotocinclus haroldoi was expanded to the Mid-Northeastern Caatinga ecoregion (Timonha river basin, Ceará State). Our study intends to make a significant contribution to current knowledge of the ichthyofauna in humid highland forest enclaves of semiarid Northeastern Brazil, identified as a priority in the conservation of the biodiversity in the Caatinga. © 2016, Universidade Estadual de Campinas UNICAMP. All rights reserved.164457463/2012-0, CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico552009/2011-3, CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico552086/2011-8, CNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Measurement of the correlation between flow harmonics of different order in lead-lead collisions at √sNN = 2.76 TeV with the ATLAS detector

    Get PDF
    Correlations between the elliptic or triangular flow coefficients vm (m=2 or 3) and other flow harmonics vn (n=2 to 5) are measured using √sNN=2.76 TeV Pb+Pb collision data collected in 2010 by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 7 μb−1. The vm−vn correlations are measured in midrapidity as a function of centrality, and, for events within the same centrality interval, as a function of event ellipticity or triangularity defined in a forward rapidity region. For events within the same centrality interval, v3 is found to be anticorrelated with v2 and this anticorrelation is consistent with similar anticorrelations between the corresponding eccentricities, ε2 and ε3. However, it is observed that v4 increases strongly with v2, and v5 increases strongly with both v2 and v3. The trend and strength of the vm−vn correlations for n=4 and 5 are found to disagree with εm−εn correlations predicted by initial-geometry models. Instead, these correlations are found to be consistent with the combined effects of a linear contribution to vn and a nonlinear term that is a function of v22 or of v2v3, as predicted by hydrodynamic models. A simple two-component fit is used to separate these two contributions. The extracted linear and nonlinear contributions to v4 and v5 are found to be consistent with previously measured event-plane correlations

    Search for vectorlike B quarks in events with one isolated lepton, missing transverse momentum, and jets at √s = 8 TeV with the ATLAS detector

    Get PDF
    A search has been performed for pair production of heavy vectorlike down-type (B) quarks. The analysis explores the lepton-plus-jets final state, characterized by events with one isolated charged lepton (electron or muon), significant missing transverse momentum, and multiple jets. One or more jets are required to be tagged as arising from b quarks, and at least one pair of jets must be tagged as arising from the hadronic decay of an electroweak boson. The analysis uses the full data sample of pp collisions recorded in 2012 by the ATLAS detector at the LHC, operating at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb −1 . No significant excess of events is observed above the expected background. Limits are set on vectorlike B production, as a function of the B branching ratios, assuming the allowable decay modes are B → Wt/Zb/Hb. In the chiral limit with a branching ratio of 100% for the decay B → Wt, the observed (expected) 95% C.L. lower limit on the vectorlike B mass is 810 GeV (760 GeV). In the case where the vectorlike B quark has branching ratio values corresponding to those of an SU(2) singlet state, the observed (expected) 95% C.L. lower limit on the vectorlike B mass is 640 GeV (505 GeV). The same analysis, when used to investigate pair production of a colored, charge 5/3 exotic fermion T 5/3 , with subsequent decay T 5/3 → Wt, sets an observed (expected) 95% C.L. lower limit on the T 5/3 mass of 840 GeV (780 GeV)
    corecore