2,519 research outputs found
More AdS_3 correlators
We compute three-point functions for the -WZNW model. After
reviewing the case of the two-point correlator, we compute spectral flow
preserving and nonpreserving correlation functions in the space-time picture
involving three vertex operators carrying an arbitrary amount of spectral flow.
When only one or two insertions have nontrivial spectral flow numbers, the
method we employ allows us to find expressions without any constraint on the
spin values. Unlike these cases, the same procedure restrains the possible spin
configurations when three vertices belong to nonzero spectral flow sectors. We
perform several consistency checks on our results. In particular, we verify
that they are in complete agreement with previously computed correlators
involving states carrying a single unit of spectral flow.Comment: 22 pages. Minor changes. Some references adde
Modification of blood pressure in postmenopausal women: role of hormone replacement therapy
The rate of hypertension increases after menopause. Whether estrogen and progesterone deficiency associated with menopause play a role in determining a worst blood pressure (BP) control is still controversial. Also, studies dealing with the administration of estrogens or hormone therapy (HT) have reported conflicting evidence. In general it seems that, despite some negative data on subgroups of later postmenopausal women obtained with oral estrogens, in particular conjugated equine estrogens (CEE), most of the data indicate neutral or beneficial effects of estrogen or HT administration on BP control of both normotensive and hypertensive women. Data obtained with ambulatory BP monitoring and with transdermal estrogens are more convincing and concordant in defining positive effect on BP control of both normotensive and hypertensive postmenopausal women. Overall progestin adjunct does not hamper the effect of estrogens. Among progestins, drospirenone, a spironolactone-derived molecule, appears to be the molecule with the best antihypertensive properties
Spectral flow and conformal blocks in AdS3
In this article we investigate the structure of the four-point functions of the
AdS3-WZNW model. We consider the integral expression for the unflowed four-point correlator involving at least one state in the discrete part of the spectrum derived by analytic continuation from the H+3 -WZNW model and we show that the conformal blocks can be obtained from those with an extremal-weight state by means of an intertwining operator. We adapt the procedure for dealing with correlators with a single unit of spectral flow charge and we get a factorized integral expression for the corresponding four-point function. We finally transform the formulas back to the space-time picture.Fil: Cagnacci, Yago Javier. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Iguri, Sergio Manuel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin
Un modello di percezione del colore, espresso da un problema di Cauchy in spazi di Banach
Scopo della tesi è studiare un modello di percezione cromatica, che descrive la propagazione dell'attività mediante un problema di Cauchy in spazi di Banach. Presentiamo dapprima il problema della stabilità delle soluzioni al problema di Cauchy tramite il metodo Lyapunov; prima in dimensione finita, e poi in spazi di Banach. Poi verifichiamo che l'equazione fondamentale di percezione cromatica ricade nel setting considerato e che il funzionale di Lyapunov associato verifica le ipotesi che assicurano la stabilità
Effect of oral phytoestrogen on androgenicity and insulin sensitivity in postmenopausal women
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90517/1/j.1463-1326.2011.01532.x.pd
Roe deer summer habitat selection at multiple spatio-temporal scales in an alpine environment
Habitat selection is a hierarchical process that may involve different patterns depending on the spatial and temporal scales of investigation. We studied habitat selection by European roe deer
(Capreolus capreolus) in a very diverse environment in the Italian eastern Alps, during summer. We sampled both coarse-grained habitat variables (topographic variables, habitat types and cover)
and fine-grained habitat variables (forage components of habitat) in used and available locations along the movement trajectories of 14 adult roe deer equipped with GPS telemetry collars. We
used conventional logistic regression to assess roe deer habitat selection at the seasonal home range scale, and conditional logistic regression to take into account the temporal aspect of habitat selection
on a weekly basis. Our results indicate that topographic variables were not significant predictors for summer roe deer habitat selection. Roe deer strongly selected dense canopy cover, probably to
avoid heat stress during warm summer days. In accordance with previous observations, roe deer preferred young forest stands dominated by pioneer species such as ash (Fraxinus spp.) and hazel
(Corylus avellana) over climax environments. Roe deer positively selected shrubs (in particular Fraxinus spp., Erica herbacea, Rhododendron spp. and Vaccinium spp.) throughout the study
period, whereas selection for grasses and sedges emerged only at the weekly scale. Habitat selection was clearly related to vegetation phenology, since roe deer selected plants in the most nutritive
phenological stages, i.e., shrubs with buds, new leaves and fruits, and newly emergent grasses and sedges. Finally, we found stronger and more significant regression coefficients for forage components
of habitat and habitat types at the weekly scale, indicating that matching spatial and temporal scales may improve our understanding of ecological patterns driving habitat selection. Conversely,
selection patterns for canopy cover did not change across scales, indicating that this variable likely drives habitat selection in a similar way throughout the entire season
Prevalence of menstrual pain in young women: what is dysmenorrhea
Objectives: This study aimed to determine the frequency of dysmenorrhea, as identified by different definitions, in a population of young women, and to investigate factors associated with this complaint.Materials and methods: A final group of 408 young women completed a self-assessment questionnaire. This was a cross-sectional analytical study.Results: Menstrual pain was reported by 84.1% of women, with 43.1% reporting that pain occurred during every period, and 41% reporting that pain occurred during some periods. Women with menstrual pain had an earlier menarche (P = 0.0002) and a longer menstrual flow (P = 0.006), and this group was characterized as having a higher prevalence of smokers (P = 0.031) and a lower prevalence of hormonal contraception users (P = 0.015). Pain intensity was correlated (r = 0.302, P < 0.0001) positively with menstrual flow length (CR = 0.336), history of abortions (CR = 3.640), and gynecological pathologies (CR = 0.948), and negatively with age at menarche (CR = \u20130.225), use of hormonal contraception (CR = \u20130.787), and history of gynecological surgery (CR = \u20132.115). Considering the parameters of menstrual pain, a need for medication, and inability to function normally (absenteeism from study or social activities) alone or together, the prevalence of dysmenorrhea is 84.1% when considering only menstrual pain, 55.2% when considering the association between menstrual pain and need for medication, 31.9% when considering the association between menstrual pain and absenteeism, and 25.3% when considering the association between menstrual pain, need for medication, and absenteeism (P < 0.0001). The probability of having more severe dysmenorrhea is directly related to pain intensity as measured by a visual analog scale, but does not coincide with it.Conclusion: Menstrual pain is a very common problem, but the need for medication and the inability to function normally occurs less frequently. Nevertheless, at least one in four women experiences distressing menstrual pain characterized by a need for medication and absenteeism from study or social activitie
The impact of reproductive life on breast cancer risk in women with family history or BRCA mutation
Reproductive history and exogenous hormonal exposures are acknowledged risk factors for breast cancer in the general population. In women at increased breast cancer risk for genetic predisposition or positive family history, data regarding these risk factors are limited or con icting, and recommendations for these categories are unclear. We evaluated the characteristics of reproductive life in 2522 women at increased genetic or familial breast cancer risk attending our Family Cancer Center. Breast cancers in BRCA mutation carriers were more likely to be hormone receptor negative, diagnosed at 35 years or before and multiple during the lifetime than tumors in women at increased familial risk, while the distribution of invasive cancers and HER2 positive tumors was similar in the different risk groups. At least one full- term pregnancy (HR 0.27; 95% CI 0.12\u20130.58; p = 0.001), breastfeeding either less (HR 0.24; 95% CI 0.09\u20130.66; p = 0.005) or more (HR 0.25; 95% IC 0.08\u20130.82; p = 0.022) than one year and late age at menopause (HR 0.10; 95% CI 0.01\u20130.82; p = 0.033) showed to be protective factors in BRCA mutation carriers, while in women at increased familial risk early age at rst full-term pregnancy (HR 0.62; 95% IC 0.38\u20130.99; p = 0.048) and late menarche (HR 0.61; 95% CI 0.42\u20130.85; p = 0.004) showed to be the main protective factors. Finally, for the entire population, combined hormonal contraceptives demonstrated to do not increase breast cancer risk. The results of our study suggest that women at high familial risk and mutation carries develop tumors with different clinical-pathological characteristics and, consequently, are in uenced by different protective and risk factors
Honey bee foraging distance depends on month and forage type
To investigate the distances at which honey bee foragers collect nectar and pollen, we analysed 5,484 decoded waggle dances made to natural forage sites to determine monthly foraging distance for each forage type. Firstly, we found significantly fewer overall dances made for pollen (16.8 %) than for non-pollen, presumably nectar (83.2 %; P < 2.2 × 10−23). When we analysed distance against month and forage type, there was a significant interaction between the two factors, which demonstrates that in some months, one forage type is collected at farther distances, but this would reverse in other months. Overall, these data suggest that distance, as a proxy for forage availability, is not significantly and consistently driven by need for one type of forage over the other
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