Loop Quantization of the Supersymmetric Two-Dimensional BF Model

In this paper we consider the quantization of the 2d BF model coupled to topological matter. Guided by the rigid supersymmetry this system can be viewed as a super-BF model, where the field content is expressed in terms of superfields. A canonical analysis is done and the constraints are then implemented at the quantum level in order to construct the Hilbert space of the theory under the perspective of Loop Quantum Gravity methods.Comment: 17 pages, Late

Symmetries and observables in topological gravity

After a brief review of topological gravity, we present a superspace approach to this theory. This formulation allows us to recover in a natural manner various known results and to gain some insight into the precise relationship between different approaches to topological gravity. Though the main focus of our work is on the vielbein formalism, we also discuss the metric approach and its relationship with the former formalism.Comment: 34 pages; a few explanations added in subsection 2.2.1, published version of pape

Does Quantum Cosmology Predict a Constant Dilatonic Field?

Quantum cosmology may permit to determine the initial conditions of the Universe. In particular, it may select a specific model between many possible classical models. In this work, we study a quantum cosmological model based on the string effective action coupled to matter. The Schutz's formalism is employed in the description of the fluid. A radiation fluid is considered. In this way, a time coordinate may be identified and the Wheeler-DeWitt equation reduces in the minisuperspace to a Schr\"odinger-like equation. It is shown that, under some quite natural assumptions, the expectation values indicate a null axionic field and a constant dilatonic field. At the same time the scale factor exhibits a bounce revealing a singularity-free cosmological model. In some cases, the mininum value of the scale factor can be related to the value of gravitational coupling.Comment: Latex file, 14 page

The Hilbert space of Chern-Simons theory on the cylinder. A Loop Quantum Gravity approach

As a laboratory for loop quantum gravity, we consider the canonical quantization of the three-dimensional Chern-Simons theory on a noncompact space with the topology of a cylinder. Working within the loop quantization formalism, we define at the quantum level the constraints appearing in the canonical approach and completely solve them, thus constructing a gauge and diffeomorphism invariant physical Hilbert space for the theory. This space turns out to be infinite dimensional, but separable.Comment: Minor changes and some references added. Latex, 16 pages, 1 figur

Construction of nonsingular cosmological solutions in string theories

We study nonsingular cosmological scenarios in a general $D$-dimensional string effective action of the dilaton-modulus-axion system in the presence of the matter source. In the standard dilatonic Brans-Dicke parameter ($\omega=-1$) with radiation, we analytically obtain singularity-free bouncing solutions where the universe starts out in a state with a finite curvature and evolves toward the weakly coupled regime. We apply this analytic method to the string-gas cosmology including the massive state in addition to the leading massless state (radiation), with and without the axion. We numerically find bouncing solutions which asymptotically approach an almost radiation-dominant universe with a decreasing curvature irrespective of the presence of the axion, implying that inclusion of the matter source is crucial for the existence of such solutions for $\omega=-1$. In the theories with $\omega \ne -1$, it is possible to obtain complete regular bouncing solutions with a finite dilaton and curvature in both past and future asymptotics for the general dimension, $D$. We also discuss the case where dilatonic higher-order corrections are involved to the tree-level effective action and demonstrate that the presence of axion/modulus fields and the matter source does not significantly affect the dynamics of the dilaton-driven inflation and the subsequent graceful exit.Comment: 27 pages, 6 eps figure

Outbreak of acute gastroenteritis in an air force base in Western Greece

BACKGROUND: On the 20(th )September 2005, soldiers and staff at the Air Force base in Western Greece experienced an outbreak of acute gastroenteritis. The purpose of this study was to identify the agent and the source of the outbreak in order to develop control measures and to avoid similar outbreaks in the future. METHODS: A case-control analytical approach was employed with 100 randomly selected cases and 66 controls. Patients completed standardized questionnaires, odds ratios were calculated and statistical significance was determined using χ(2 )test. In addition, to identify the source of the infection, we performed bacteriological examination of food samples (included raw beef, cooked minced meat, grated cheese and grated cheese in sealed package) collected from the cuisine of the military unit. RESULTS: More than 600 out of the 1,050 individuals who ate lunch that day, became ill. The overall attack rate, as the military doctor of the unit estimated it, was at least 60%. The overall odds ratio of gastroenteritis among those who had lunch was 370 (95% CI: 48–7700) as compared to those who didn't eat lunch. Among the symptoms the most prominent were watery diarrhoea (96%) and abdominal pain (73%). The mean incubation period was 9 h and the median duration of the symptoms was 21 h. In the bacteriological examination, Staphylococcus aureus was detected in a sample of raw beef (2,000 cfu per g) and in two samples of grated cheese; leftover cheese from lunch (7,800 cfu per g) and an unopened package purchased from the market (3,000 cfu per g). CONCLUSION: The findings of this study suggest that the aetiological agent of this outbreak was S. aureus. The food vehicle was the grated cheese, which was mixed with the beef and served for lunch in the military unit. This outbreak highlights the capacity of enterotoxin-producing bacteria to cause short term, moderately-severe illness in a young and healthy population. It underscores the need for proper food handling practices and reinforces the public health importance of timely notification of such outbreaks

Regular cosmological solutions in low energy effective action from string theories

The possibility of obtaining singularity free cosmological solutions in four dimensional effective actions motivated by string theory is investigated. In these effective actions, in addition to the Einstein-Hilbert term, the dilatonic and the axionic fields are also considered as well as terms coming from the Ramond-Ramond sector. A radiation fluid is coupled to the field equations, which appears as a consequence of the Maxwellian terms in the Ramond-Ramond sector. Singularity free bouncing solutions in which the dilaton is finite and strictly positive are obtained for models with flat or negative curvature spatial sections when the dilatonic coupling constant is such that $\omega < - 3/2$, which may appear in the so called $F$ theory in 12 dimensions. These bouncing phases are smoothly connected to the radiation dominated expansion phase of the standard cosmological model, and the asymptotic pasts correspond to very large flat spacetimes.Comment: 10 pages, ReVTeX format, 2 figures, to appear in Phys. Rev. D (2003

European Summit on the Prevention and Self-Management of Chronic Respiratory Diseases: report of the European Union Parliament Summit (29 March 2017)

On March 29, 2017, a European Summit on the Prevention and Self-Management of Chronic Respiratory Diseases (CRD) was organized by the European Forum for Research and Education in Allergy and Airway Diseases. The event took place in the European Parliament of Brussels and was hosted by MEP David Borrelli and MEP Sirpa Pietikainen. The aim of the Summit was to correspond to the needs of the European Commission and of patients suffering from CRD to join forces in Europe for the prevention and self-management. Delegates of the European Rhinologic Society, European Respiratory Society, European Academy of Allergy and Clinical Immunology, European Academy of Paediatrics, and European Patients Organization EFA all lectured on their vision and action plan to join forces in achieving adequate prevention and self-management of CRD in the context of Precision Medicine. Recent data highlight the preventive capacity of education on optimal care pathways for CRD. Self-management and patient empowerment can be achieved by novel educational on-line materials and by novel mobile health tools enabling patients and doctors to monitor and optimally treat CRDs based on the level of control. This report summarizes the contributions of the representatives of different European academic stakeholders in the field of CRD

The EUFOREA pocket guide for chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is known to affect around 5 % of the total population, with major impact on the quality of life of those severely affected (1). Despite a substantial burden on individuals, society and health economies, CRS often remains underdiagnosed, under-estimated and under-treated (2). International guidelines like the European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS) (3) and the International Consensus statement on Allergy and Rhinology: Rhinosinusitis 2021 (ICAR) (4) offer physicians insight into the recommended treatment options for CRS, with an overview of effective strategies and guidance of diagnosis and care throughout the disease journey of CRS