4,387 research outputs found
Sexual Segregation in Iberian Noctule Bats
Sexual segregation during the breeding season is common in many temperate bat species, and may be related to sex-specific thermoregulatory, microclimatic, or energetic requirements. We compiled capture data for 3 species of Nyctalus (noctule bats) obtained over .20 years to study reproductive and migratory strategies of these species in southwestern Europe. Within the Iberian Peninsula, several different strategies regarding sex distribution and migratory behavior were observed within each of the 3 Nyctalus species. In the northern part of Iberia there are populations of the 3 species composed of males all year-round with females appearing only during the mating season. Reproduction by females in this area has not been confirmed. In central and southern Iberia there are breeding populations in which sexual segregation occurs only at the roosts or at a regional scale, possibly with females located at lower elevations during the breeding season. Female-biased, long-distance migration is likely to be the cause of sexual segregation in populations of N. noctula and N. leisleri in northern and central Iberia, but not of N. lasiopterus, absent in central Europe. For this latter species, segregation by elevation also could occur in northern Iberia. The Iberian Peninsula is a good example of how breeding strategies and migratory behavior in bats can be very flexible and vary across relatively small geographical scales.Peer reviewe
Electroweak radiative corrections to at linear colliders
We calculate the electroweak radiative
corrections to at a electron-positron linear collider
(LC) in the standard model. We analyze the dependence of the corrections on the Higgs boson mass and
colliding energy , and find that the corrections significantly
decrease or increase the Born cross section depending on the colliding energy.
The numerical results show that the relative
correction is strongly related to the Higgs boson mass when ,
and for the relative correction ranges from -31.3% to 2.3% as
the increment of the colliding energy from 500 GeV to 2 TeV.Comment: 16 pages, 7 figure
Experiencias en el Uso de Códigos Neutrónicos en la Docencia en IngenierÃa Nuclear
[ES] El equipo de innovación docente SEERISN (Simulación en la Enseñanza de Radiaciones Ionizantes y Seguridad Nuclear) de la UPV ha retomado sus actividades con el objetivo de abordar desde un punto de vista global la necesidad de formar a los estudiantes en el uso de códigos neutrónicos para el cálculo de reactores nucleares tal como se demanda desde las empresas del sector nuclear. El análisis de las diferentes actividades que ya se estaban realizando ha puesto de manifiesto la necesidad de revisar estas actividades para una introducción gradual y especÃfica del uso de códigos neutrónicos en varias asignaturas de una manera sistemática y consciente, estableciendo grados de dificultad crecientes adecuados a cada titulación incluyendo medidas de evaluación del grado de consecución de las mismas. Este proceso se ha planteado en diferentes etapas y acciones. En este trabajo se presenta la primera fase de implantación en una asignatura de grado y los resultados obtenidos.[ES] The teaching innovation team SEERISN (Simulation in the Teaching of Ionizing Radiation
and Nuclear Safety) of the UPV has resumed its activities with the aim of addressing, from a
global point of view, the need to train students in the use of neutron codes to the calculation
of nuclear reactors as demanded by companies in the nuclear sector. The analysis of the
different activities that were already being carried out has revealed the need to review these
activities for a gradual and specific introduction of the use of neutronic codes in various
subjects in a systematic and conscious manner, establishing increasing degrees of difficulty
appropriate to each qualification including evaluation measures of the degree of
achievement of the same. This process has been proposed in different stages and actions.
This paper presents the first phase of implementation in one subject for a degree and the
results obtained.Barrachina, T.; Juste, B.; Miró, R.; Verdú, G. (2023). Experiencias en el Uso de Códigos Neutrónicos en la Docencia en IngenierÃa Nuclear. Editorial Universitat Politècnica de València. 679-687. https://doi.org/10.4995/INRED2023.2023.1656867968
QCD and electroweak corrections to production in collision
We calculate the QCD and
electroweak one-loop corrections in the Standard Model framework, to the
production of an intermediate Higgs boson associated with pair via
fusion at an electron-positron linear collider (LC). We find
the QCD corrections can be larger than the electroweak ones, with the variations of the Higgs boson
mass and colliding energy . Both corrections may
significantly decrease or increase the Born cross section. The numerical
results show that the relative corrections from QCD to the process \eep may
reach 34.8%, when GeV and GeV, while those from
electroweak can be -13.1%, -15.8% and -12.0%, at GeV, 1 TeV
and 2 TeV respectively.Comment: 38 pages, 16 figure
Higgs production in association with top quark pair at e+e- colliders in theories of higher dimensional gravity
The models of large extra compact dimensions, as suggested by Arkani-Hamed,
Dimopoulos and Dvali, predict exciting phenomenological consequences with
gravitational interactions becoming strong at the TeV scale. Such theories can
be tested at the existing and future colliders. In this paper, we study the
contribution of virtual Kaluza-Klein excitations in the process at future linear collider (NLC). We find that the virtual exchange
KK gravitons can modify the cross-section
significantly from its Standard Model value and will allow the effective string
scale to be probed up to 7.9 TeV.Comment: 10 pages, Latex, 4 postscript figure
Report of the 2005 Snowmass Top/QCD Working Group
This report discusses several topics in both top quark physics and QCD at an
International Linear Collider (ILC). Issues such as measurements at the
threshold, including both theoretical and machine requirements, and
the determination of electroweak top quark couplings, are reviewed. New results
concerning the potential of a 500 GeV collider for measuring
couplings and the top quark Yukawa coupling are presented. The status of higher
order QCD corrections to jet production cross sections, heavy quark form
factors, and longitudinal gauge boson scattering, needed for percent-level
studies at the ILC, are reviewed. A new study of the measurement of the
hadronic structure of the photon at a collider is presented. The
effects on top quark properties from several models of new physics, including
composite models, Little Higgs theories, and CPT violation, are studied.Comment: 39 pages, many figs; typos fixed and refs added. Contributed to the
2005 International Linear Collider Physics and Detector Workshop and 2nd ILC
Accelerator Workshop, Snowmass, Colorado, 14-27 Aug 200
LHC Discovery Potential for Non-Standard Higgs Bosons in the 3b Channel
In a variety of well motivated models, such as two Higgs Doublet Models
(2HDMs) and the Minimal Supersymmetric Standard Model (MSSM), there are neutral
Higgs bosons that have significantly enhanced couplings to b-quarks and tau
leptons in comparison to those of the SM Higgs. These so called non-standard
Higgs bosons could be copiously produced at the LHC in association with b
quarks, and subsequently decay into b-quark pairs. However, this production
channel suffers from large irreducible QCD backgrounds. We propose a new search
strategy for non-standard neutral Higgs bosons at the 7 TeV LHC in the 3b's
final state topology. We perform a simulation of the signal and backgrounds,
using state of the art tools and methods for different sets of selection cuts,
and conclude that neutral Higgs bosons with couplings to b-quarks of about 0.3
or larger, and masses up to 400 GeV, could be seen with a luminosity of 30
fb^{-1}. In the case of the MSSM we also discuss the complementarity between
the 3b channel and the inclusive tau pair channel in exploring the
supersymmetric parameter space.Comment: 14 pages, 3 figures, 4 tables, references added, published versio
Radiative corrections to Higgs-boson production in association with top-quark pairs at e+ e- colliders
We have calculated the complete O(alpha) and O(alpha_s) radiative corrections
to the Higgs-production process e+ e- -> t anti-t H in the Standard Model. This
process is particularly interesting for the measurement of the top-quark Yukawa
coupling at a future e+ e- collider. The calculation of the O(alpha)
corrections is described in some detail including, in particular, the treatment
of the soft and collinear singularities. The discussion of numerical results
focuses on the total cross section as well as on angular and energy
distributions of the outgoing particles. The electroweak corrections turn out
to be sizable and can reach the order of +/-10%. They result from cancellations
between electromagnetic, fermionic, and weak bosonic corrections, each of which
are of the order of +/-10%.Comment: 32 pages, LaTeX, 12 postscript figure
El dÃa de la semana en la exploración de la orientación en el tiempo
Sr. Editor: La exploración de la orientación en el tiempo (OT) se aplica de forma habitual en el examen del estado mental y en especial, en el cribado del deterioro cognitivo. En un trabajo previo, nuestro grupo aportó una nueva técnica de exploración de la OT, aplicando una pregunta abierta («dÃgame la fecha de hoy lo más completa posible») y cuantificando las respuestas espontáneas del paciente mediante la suma de 2 escalas, una semántica que puntúa los campos de la fecha que el paciente genera (dÃa del mes —D—, mes —M—, año —A— y dÃa de la semana —S—), y otra episódica, que puntúa la información episódica correcta para cada campo..
Effects Of Length, Complexity, And Grammatical Correctness On Stuttering In Spanish-Speaking Preschool Children
Purpose: To explore the effects of utterance length, syntactic complexity, and grammatical correctness on stuttering in the spontaneous speech of young, monolingual Spanish-speaking children. Method: Spontaneous speech samples of 11 monolingual Spanish-speaking children who stuttered, ages 35 to 70 months, were examined. Mean number of syllables, total number of clauses, utterance complexity (i.e., containing no clauses, simple clauses, or subordinate and/or conjoined clauses), and grammatical correctness (i.e., the presence or absence of morphological and syntactical errors) in stuttered and fluent utterances were compared. Results: Findings revealed that stuttered utterances in Spanish tended to be longer and more often grammatically incorrect, and contain more clauses, including more subordinate and/or conjoined clauses. However, when controlling for the interrelatedness of syllable number and clause number and complexity, only utterance length and grammatical incorrectness were significant predictors of stuttering in the spontaneous speech of these Spanish-speaking children. Use of complex utterances did not appear to contribute to the prediction of stuttering when controlling for utterance length. Conclusions: Results from the present study were consistent with many earlier reports of English-speaking children. Both length and grammatical factors appear to affect stuttering in Spanish-speaking children. Grammatical errors, however, served as the greatest predictor of stuttering.Communication Sciences and Disorder
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