150 research outputs found
Gauge-independent renormalization in the 2HDM
We present a consistent renormalization scheme for the CP-conserving
Two-Higgs-Doublet Model based on renormalization of the mixing
angles and the soft--symmetry-breaking scale in the Higgs sector.
This scheme requires to treat tadpoles fully consistently in all steps of the
calculation in order to provide gauge-independent -matrix elements. We show
how bare physical parameters have to be defined and verify the gauge
independence of physical quantities by explicit calculations in a general
-gauge. The procedure is straightforward and applicable to other
models with extended Higgs sectors. In contrast to the proposed scheme, the
renormalization of the mixing angles combined with popular
on-shell renormalization schemes gives rise to gauge-dependent results already
at the one-loop level. We present explicit results for electroweak NLO
corrections to selected processes in the appropriately renormalized
Two-Higgs-Doublet Model and in particular discuss their scale dependence.Comment: 52 pages, PDFLaTeX, PDF figures, JHEP version with Eq. (5.23)
correcte
Many faces of low mass neutralino dark matter in the unconstrained MSSM, LHC data and new signals
If all strongly interacting sparticles (the squarks and the gluinos) in an
unconstrained minimal supersymmetric standard model (MSSM) are heavier than the
corresponding mass lower limits in the minimal supergravity (mSUGRA) model,
obtained by the current LHC experiments, then the existing data allow a variety
of electroweak (EW) sectors with light sparticles yielding dark matter (DM)
relic density allowed by the WMAP data. Some of the sparticles may lie just
above the existing lower bounds from LEP and lead to many novel DM producing
mechanisms not common in mSUGRA. This is illustrated by revisiting the above
squark-gluino mass limits obtained by the ATLAS Collaboration, with an
unconstrained EW sector with masses not correlated with the strong sector.
Using their selection criteria and the corresponding cross section limits, we
find at the generator level using Pythia, that the changes in the mass limits,
if any, are by at most 10-12% in most scenarios. In some cases, however, the
relaxation of the gluino mass limits are larger (). If a subset of
the strongly interacting sparticles in an unconstrained MSSM are within the
reach of the LHC, then signals sensitive to the EW sector may be obtained. This
is illustrated by simulating the \etslash, , and \etslash signals in i) the light stop scenario and ii) the light
stop-gluino scenario with various light EW sectors allowed by the WMAP data.
Some of the more general models may be realized with non-universal scalar and
gaugino masses.Comment: 27 pages, 1 figure, references added, minor changes in text, to
appear in JHE
Investigation of the level of knowledge in different countries about edible insects : cluster segmentation
This study aimed to investigate the level of knowledge about edible insects (EIs) in a
sample of people from thirteen countries (Croatia, Greece, Latvia, Lebanon, Lithuania, Mexico,
Poland, Portugal, Romania, Serbia, Slovenia, Spain, and Turkey). Data collection was based on
a questionnaire survey applied through online tools between July and November 2021. For data
analysis, techniques such as factor analysis, cluster analysis, and chi-square tests were used, with
a significance level of 5%. A total of 27 items were used to measure knowledge on a five-point
Likert scale. Applying factor analysis with principal components and Varimax rotation, a solution
that explains about 55% of variance was obtained. This accounts for four factors that retained
22 of the 27 initial items: F1 = Sustainability (8 items), F2 = Nutrition (8 items), F3 = Production
Factors (2 items), and F4 = Health Concerns (4 items). Internal consistency was evaluated through
Cronbach’s alpha. The cluster analysis consisted of the application of hierarchical methods followed
by k-means and produced three clusters (1—‘fearful’, 2—‘farming,’ and 3—‘ecological’ individuals).
The characterisation of the clusters revealed that age did not influence cluster membership, while sex,
education, country, living environment, professional area, and income all influenced the composition
of the clusters. While participants from Mexico and Spain were fewer in the ‘fearful’ cluster, in those
from Greece, Latvia, Lebanon, and Turkey, the situation was opposed. Participants from rural areas
were mostly in cluster 2, which also included a higher percentage of participants with lower income.
Participants from professional areas linked with biology, food, and nutrition were mostly in cluster 3.
In this way, we concluded that the level of knowledge about EIs is highly variable according to the
individual characteristics, namely that the social and cultural influences of the different countries
lead to distinct levels of knowledge and interpretation of information, thus producing divergent approaches to the consumption of insects—some more reluctant and measuring possible risks. In
contrast, others consider EIs a good and sustainable protein-food alternative.info:eu-repo/semantics/publishedVersio
Edible insects – exotic food or gastronomic innovation? Study involving 14 countries
This work was supported by the FCT—Foundation for Science and Technology, I.P. Furthermore, we would like to thank the CERNAS, CIDEI, and UCISA:E Research Centers and the Polytechnic University of Viseu for their support. This research was developed in the ambit of project “EISuFood—Edible Insects as Sustainable Food”, with Reference CERNAS-IPV/2020/003 (10.54499/UIDP/00681/2020).This study explores the perceptions about edible insects and their usage in modern gastronomy. Data were collected through questionnaire survey in 14 countries, and 7222 responses were obtained. ANOVA and factor analysis were used, respectively to evaluate differences between groups and to analyze the scale items. The results showed that participants showed higher agreement toward insects being considered exotic foods and being associated with taboos and neophobia. Some sociodemographic factors (country, age class, education level and income) were proven to significantly influence with the perceptions. while sex and living environment did not. Factor analysis extracted three factors, one associated with the uses of insects in gastronomy, another associated with insects as foods and a third about insects not being proper for human consumption. In conclusion, the work revealed differences between countries in the perceptions about edible insects, and that these perceptions were also significantly influenced according to other sociodemographic variables.This work is funded by National Funds through the FCT - Foundation for Science and Technology, I.P., within the scope of the projects Ref. [UIDB/00681/2020] (CERNAS), [UIDB/05507/2020] (CIDEI) and [UIDB/00742/2020] (UICISA:E) research unit.info:eu-repo/semantics/publishedVersio
Conductance Ratios and Cellular Identity
Recent experimental evidence suggests that coordinated expression of ion channels plays a role in constraining neuronal electrical activity. In particular, each neuronal cell type of the crustacean stomatogastric ganglion exhibits a unique set of positive linear correlations between ionic membrane conductances. These data suggest a causal relationship between expressed conductance correlations and features of cellular identity, namely electrical activity type. To test this idea, we used an existing database of conductance-based model neurons. We partitioned this database based on various measures of intrinsic activity, to approximate distinctions between biological cell types. We then tested individual conductance pairs for linear dependence to identify correlations. Contrary to experimental evidence, in which all conductance correlations are positive, 32% of correlations seen in this database were negative relationships. In addition, 80% of correlations seen here involved at least one calcium conductance, which have been difficult to measure experimentally. Similar to experimental results, each activity type investigated had a unique combination of correlated conductances. Finally, we found that populations of models that conform to a specific conductance correlation have a higher likelihood of exhibiting a particular feature of electrical activity. We conclude that regulating conductance ratios can support proper electrical activity of a wide range of cell types, particularly when the identity of the cell is well-defined by one or two features of its activity. Furthermore, we predict that previously unseen negative correlations and correlations involving calcium conductances are biologically plausible
Is the Concept of Quality of Life Relevant for Multiple Sclerosis Patients with Cognitive Impairment? Preliminary Results of a Cross-Sectional Study
Background: Cognitive impairment occurs in about 50 % of multiple sclerosis (MS) patients, and the use of self-reported outcomes for evaluating treatment and managing care among subjects with cognitive dysfunction has been questioned. The aim of this study was to provide new evidence about the suitability of self-reported outcomes for use in this specific population by exploring the internal structure, reliability and external validity of a specific quality of life (QoL) instrument, the Multiple Sclerosis International Quality of Life questionnaire (MusiQoL). Methods: Design: cross-sectional study. Inclusion criteria: MS patients of any disease subtype. Data collection: sociodemographic (age, gender, marital status, education level, and occupational activity) and clinical data (MS subtype, Expanded Disability Status Scale, disease duration); QoL (MusiQoL and SF36); and neuropsychological performance (Stroop color-word test). Statistical analysis: confirmatory factor analysis, item-dimension correlations, Cronbach’s alpha coefficients, Rasch statistics, relationships between MusiQoL dimensions and other parameters. Principal Findings: One hundred and twenty-four consecutive patients were enrolled. QoL scores did not differ between the 69 cognitively non-impaired patients and the 55 cognitively impaired patients, except for the symptoms dimension. The confirmatory factor analysis performed among the impaired subjects showed that the structure of the questionnaire matched with the initial structure of the MusiQoL. The unidimensionality of the MusiQoL dimensions was preserved, and th
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