295 research outputs found
Calibración de una nariz electrónica tipo QCM y relación con las especificaciones para la calidad de la pera.
Las microbalanzas de cristal de cuarzo (QCM), son mecanismos piezoeléctricos, para transformarlos en sensores químicos es necesario recubrirlos con una capa de material capaz de capturar las moléculas del ambiente. Cuando una masa es adsorbida sobre la superficie del cristal, la frecuencia de oscilación cambia en proporción a la cantidad de masa (Di Natale et al. 1997). La respuesta de los sensores depende de numerosos factores que pueden ser difíciles de controlar, tales como la temperatura y la humedad del gas portador. Todos estos factores producen cambios en la selectividad de los sensores que afectan a la reproducibilidad de las medidas. A pesar de la existencia de numerosos estudios no existe ningún procedimiento establecido para la calibración de las QCM en relación con la sensibilidad necesaria en los sensores para el aseguramiento de la calidad en pera o en otras frutas
Utilización de una nariz electrónica tipo QCM para la evaluación de la calidad aromática en pera y manzana.
The "Libra Nose" electronic nose has eight Quartz Microbalance Sensors. When gas molecules are adsorbed onto the quartz crystal surface, the oscillation frequency changes in proportion to the amount of mass. The response of sensors depends on numerous factors that may be difficult to control, such as the temperature and the humidity of the carrier gas. All these factors cause changes in the selectivity of sensors affecting the reproducibility of measurements. In this paper additive a multiplicative corrections are proposed to be applied to the raw sensors's signal in order to eliminate sources of variations. After these corrections, the sensors' response gives useful information to distinguish between batch of apples and pears with different ripeness stage
Segurança Na Mudança Direta De Natalizumabe Para Fingolimode Em Um Grupo De Pacientes Com Esclerose Múltipla E Positivos Para Jcv
To assess safety of the switch between natalizumab and fingolimod without a washout period. Methods: Prospective data on 25 JCV positive patients who underwent this medication switch were collected and analyzed. Results: After a median period of nine months from the medication switch, there were no safety issues to report. The patients had good disease control and no adverse events were reported. Conclusion: Washout may not be necessary in daily practice when switching from natalizumab to fingolimod. Expertise on multiple sclerosis management, however, is essential for drug switching. © 2016, Associacao Arquivos de Neuro-Psiquiatria. All Rights Reserved.74865065
Making things happen : a model of proactive motivation
Being proactive is about making things happen, anticipating and preventing problems, and seizing opportunities. It involves self-initiated efforts to bring about change in the work environment and/or oneself to achieve a different future. The authors develop existing perspectives on this topic by identifying proactivity as a goal-driven process involving both the setting of a proactive goal (proactive goal generation) and striving to achieve that proactive goal (proactive goal striving). The authors identify a range of proactive goals that individuals can pursue in organizations. These vary on two dimensions: the future they aim to bring about (achieving a better personal fit within one’s work environment, improving the organization’s internal functioning, or enhancing the organization’s strategic fit with its environment) and whether the self or situation is being changed. The authors then identify “can do,” “reason to,” and “energized to” motivational states that prompt proactive goal generation and sustain goal striving. Can do motivation arises from perceptions of self-efficacy, control, and (low) cost. Reason to motivation relates to why someone is proactive, including reasons flowing from intrinsic, integrated, and identified motivation. Energized to motivation refers to activated positive affective states that prompt proactive goal processes. The authors suggest more distal antecedents, including individual differences (e.g., personality, values, knowledge and ability) as well as contextual variations in leadership, work design, and interpersonal climate, that influence the proactive motivational states and thereby boost or inhibit proactive goal processes. Finally, the authors summarize priorities for future researc
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Teaching precision farming and entrepreneurship for European students: Sparkle online course
Within the framework of the European project named ‘SPARKLE’, an online course was created after studying educational needs on precision agriculture (PA), state of the art of technologies and a prospective study of the commercial sector. Five educational and research institutions, high-tech farms and enterprises specializing in technology transfer created the syllabus of the course and the platform contents. The course was designed to provide 30 h of student dedication, via online presentations, documents and videos for each topic. A free pilot course started in April 2020 and 385 students from Italy, Portugal, Greece & Spain enrolled. To trace performance and acquisition of competences, questionnaires were completed by students for each topic and a final overall test. Students’ opinions about the course were also registered using anonymous polls, and results evaluated, to be able to enhance the Sparkle course for subsequent editions. Students also took part in a business model competition, to solve real challenges proposed by farms, related to the use of these technologies
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
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