Multi-instanton and string loop corrections in toroidal orbifold models

We analyze N=2 (perturbative and non-perturbative) corrections to the effective theory in type I orbifold models where a dual heterotic description is available. These corrections may play an important role in phenomenological scenarios. More precisely, we consider two particular compactifications: the Bianchi-Sagnotti-Gimon-Polchinski orbifold and a freely-acting Z_2 x Z_2 orbifold with N=1 supersymmetry and gauge group SO(q) x SO(32-q). By exploiting perturbative calculations of the physical gauge couplings on the heterotic side, we obtain multi-instanton and one-loop string corrections to the K\"ahler potential and the gauge kinetic function for these models. The non-perturbative corrections appear as sums over relevant Hecke operators, whereas the one-loop correction to the K\"ahler potential matches the expression proposed in [1,2]. We argue that these corrections are universal in a given class of models where target-space modular invariance (or a subgroup of it) holds.Comment: 37 pages, 3 figure

Flux-induced Soft Terms on Type IIB/F-theory Matter Curves and Hypercharge Dependent Scalar Masses

Closed string fluxes induce generically SUSY-breaking soft terms on supersymmetric type IIB orientifold compactifications with D3/D7 branes. This was studied in the past by inserting those fluxes on the DBI+CS actions for adjoint D3/D7 fields, where D7-branes had no magnetic fluxes. In the present work we generalise those computations to the phenomenologically more relevant case of chiral bi-fundamental fields laying at 7-brane intersections and F-theory local matter curves. We also include the effect of 7-brane magnetic flux as well as more general closed string backgrounds, including the effect of distant (anti-)D3-branes. We discuss several applications of our results. We find that squark/slepton masses become in general flux-dependent in F-theory GUT's. Hypercharge-dependent non-universal scalar masses with a characteristic sfermion hierarchy m_E^2 < m_L^2 < m_Q^2 < m_D^2 < m_U^2 are obtained. There are also flavor-violating soft terms both for matter fields living at intersecting 7-branes or on D3-branes at singularities. They point at a very heavy sfermion spectrum to avoid FCNC constraints. We also discuss the possible microscopic description of the fine-tuning of the EW Higgs boson in compactifications with a MSSM spectrum.Comment: 67 pages, 2 figures, 2 table

Closed-loop deep brain stimulation based on a stream-clustering system

Idiopathic Parkinsons disease (PD) is currently the second most important neurodegenerative disease in incidence. Deep brain stimulation (DBS) constitutes a successful and necessary therapy; however, the continuous stimulation it provides can be associated with multiple side effects. DBS uses an implanted pulse generator that delivers, through a set of electrodes, electrical stimulation to the target area, normally the Sub Thalamic Nucleus. Recently, Closed-loop DBS has emerged as a promising new strategy, where the device stimulates only when necessary, thereby reducing any adverse effects. Here, we present a Closed-loop DBS system for PD, which is able to recognize, with 100% accuracy, when the patient is going to enter into the tremor phase, thus allowing the device to stimulate only in such cases. The expert system has been designed and implemented within the data stream mining paradigm, suitable for our scenario since it can cope with continuous data of a theoretical infinite length and with a certain variability, which uses the synchronization among the neural population within the Sub Thalamic Nucleus as the continuous data stream input to the system.Depto. de Psicología Experimental, Procesos Cognitivos y LogopediaDepto. de MedicinaFac. de PsicologíaFac. de MedicinaTRUEpu

Deck-tower interaction in the transverse seismic response of cable-stayed bridges and optimum con figurations

Modern design solutions in cable-stayed bridges give a significant importance to the seismic response in the transverse direction. This work is focused on the dynamic interaction between the deck and the towers, exploring the key role of different vibration modes. An extensive parametric analysis is proposed to address the influence of the main span length, the tower geometry, the cable-system arrangement, the width and height of the deck and the soil conditions. It is demonstrated that the vibration modes that govern the seismic response of cable-stayed bridges in the transverse direction involve the interaction between the tower and the deck, but the order of these modes and the parts of the deck that are affected change with the main span length. It is also observed that the interaction between the deck and the towers during the earthquake is maximised if their isolated vibration frequencies are close to each other, leading to a significantly large seismic demand. Analytical expressions are proposed to obtain the critical frequencies of the towers for which these interactions arise, and recommendations are given to define the tower geometry in order to avoid such problematic scenarios

Effect of spatial variability of earthquakes on cable-stayed bridges

This paper focuses on the effect of spatially variable ground motions on the towers of cable-stayed bridges with 200, 400 and 600m main spans. Seismic analysis of the bridges is performed, taking account of different sources of the spatial variability, namely; incoherence and wave passage effects. To address these effects, the response of the towers is assessed under the effect of different propagation velocities of the seismic waves and different assumptions on the coherency of the ground motion, to conclude that the effect of spatially variable motions on the seismic response of cable-stayed bridges is dependent on the assumed wave propagation velocity and rate of coherency

Advanced onboard storage concepts for natural gas-fueled automotive vehicles

The evaluation of several advanced concepts for storing natural gas at reduced pressure is presented. The advanced concepts include adsorption on high surface area carbon, adsorption in high porosity zeolite, storage in clathration compounds, and storage by dissolution in liquid solvents. High surface area carbons with high packing density are the best low pressure storage mediums. A simple mathematical model is used to compare adsorption storage on a state of the art carbon with compression storage. The model indicates that a vehicle using adsorption storage of natural gas at 3.6 MPa will have 36 percent of the range, on the EPA city cycle, of a vehicle operating on a compression storage system having the same physical size and a peak storage pressure of 21 MPa. Preliminary experiments and current literature suggest that the storage capacity of state of the art carbons could be improved by as much as 50 percent, and that adsorption systems having a capacity equal to compression storage at 14 MPa are possible without exceeding a maximum pressure of 3.6 MPa

Promoção de eventos culturais na Biblioteca da Embrapa Florestas: responsabilidade social e cultural.

Apresenta uma reflexão sobre a responsabilidade e compromisso social das bibliotecas e descreve ações desenvolvidas por uma biblioteca especializada na área de pesquisa com o objetivo de promover a biblioteca, incentivar atividades culturais, bem como de sociabilizar a mesma na empresa

Human papilloma virus genotype distribution and risk factor analysis amongst reproductive aged women in urban Gambia

Purpose. Cervical cancer is the most frequently diagnosed female cancer in The Gambia, representing approximately 30% of cases. In 2014, the quadrivalent human papilloma virus (HPV) vaccine was introduced, which offers protection against HPV genotypes 6, 11, 16 and 18. To evaluate the potential effectiveness of this vaccine, genotype distribution and risk factor analysis were assessed. Methodology. Endocervical samples (n=232) were collected from women aged 20-49 years residing in urban Gambia. A questionnaire was administered to capture socio-demographic and cervical cancer risk factors. HPV detection and genotyping was performed by PCR amplification of the L1 major capsid gene and analysis of sequenced PCR products. Results/ Key Findings. The prevalence of HPV was 12% (28/232) and the high risk (HR) genotype HPV 52 (5/28) was the most prevalent genotype. HR-HPV sequences had high identity (≥ 90 %) to isolates which originated from America, Europe and Asia but not from Africa. Half (14/28) of participants were co-infected with Ureaplasma urealyticum/parvum, which increases the risk of progression to cervical cancer. Female genital mutilation and the use of hormone contraception for >5 years were identified as potential risk factors for HPV infection. Ethnicity-associated differences were also noted; participants of the Fula ethnic group had a higher prevalence of HR-HPV infection (31.3%) compared to the Mandinka (18.8%) and Wollof (12.5%) groups. Conclusion. These data may have a significant public health impact as the HPV quadrivalent vaccine may be of limited value if the circulating non-HPV 16/18 HR-genotypes are responsible for cytological abnormalities of the cervix