Lorentz-violating dimension-five operator contribution to the black body radiation

We investigate the thermodynamics of a photon gas in an effective field theory model that describes Lorentz violations through dimension-five operators and Horava-Lifshitz theory. We explore the electrodynamics of the model which includes higher order derivatives in the Lagrangian that can modify the dispersion relation for the propagation of the photons. We shall focus on the deformed black body radiation spectrum and modified Stefan-Boltzmann law to address the allowed bounds on the Lorentz-violating parameter.Comment: 8 pages, 6 figures. Version published in PL

Person localization using sensor information fusion

Nowadays the incredible grow of mobile devices market led to the need for location-aware applications. However, sometimes person location is di cult to obtain, since most of these devices only have a GPS (Global Positioning System) chip to retrieve location. In order to sup- press this limitation and to provide location everywhere (even where a structured environment doesn't exist) a wearable inertial navigation sys- tem is proposed, which is a convenient way to track people in situations where other localization systems fail. The system combines pedestrian dead reckoning with GPS, using widely available, low-cost and low-power hardware components. The system innovation is the information fusion and the use of probabilistic methods to learn persons gait behavior to correct, in real-time, the drift errors given by the sensors.This work is part-funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT Fundao para a Cincia e a Tecnologia (Portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER- 028980 (PTDC/EEI-SII/1386/2012). Ricardo also acknowledge FCT for the support of his work through the PhD grant (SFRH/DB/70248/2010)

Vascular trauma: a five year review

O presente trabalho pretende avaliar a casuística dos traumatismos vasculares agudos admitidos no Serviço de Cirurgia Vascular dos Hospitais da Universidade de Coimbra (HUC) durante o período de 5 anos, compreendido entre Julho de 2004 e Junho de 2009. Foram avaliados 97 doentes, sendo a principal causa de traumatismo as lesões iatrogénicas, seguida dos acidentes de viação. No grupo de doentes não relacionados com procedimentos coronários percutâneos verificou-se que no membro superior as artérias umeral e radial foram as mais afectadas, enquanto no membro inferior foram as artérias femoral superficial e poplítea. A isquémia aguda foi a principal forma de apresentação. Relativamente ao tratamento deste grupo de doentes, a RATT (ressecção e anastomose topo-topo) e o enxerto foram os mais utlizados no membro superior, enquanto a trombectomia e o bypass foram as técnicas mais aplicadas a nível do membro inferior. Não houve mortalidade mas a morbilidade foi elevada, predominando as lesões neurológicas nos traumatismos do membro superior, e a amputação nos do membro inferior. Os resultados deste trabalho foram concordantes com o que está publicado na literatura em que se demonstra um aumento progressivo dos traumatismos de origem iatrogénica

A rare cause of portal hypertension: case report

Apresenta-se caso clínico de doente com quadro de hipertensão portal pela presença de fístula artério-venosa entre a artéria gastroduodenal e a veia porta. Indivíduo do sexo masculino, de 77 anos, previamente saudável, com ascite volumosa de instalação recente. Hemorragia digestiva alta por rotura de varizes esofágicas. TAC abdominal revelando acentuada dilatação da veia porta (30 mm), envolvida em fístula artério-venosa com origem na artéria gastroduodenal; fígado sem estigmas de hepatopatia crónica e sem nódulos; ascite volumosa. Procedeu-se à laparotomia com drenagem de ascite, isolamento e laqueação do trajecto fístuloso entre a artéria gastroduodenal e a veia porta. Sem complicações intra-operatórias. Ao 18º dia, após regressão da ascite, teve alta medicado com diurético

Noncommutative Maxwell-Chern-Simons theory in three dimensions and its dual

We consider the Maxwell-Chern-Simons theory in noncommutative three dimensional space-time. We show that the Seiberg-Witten map is ambiguous due to the dimensional coupling constant. To get the dual theory we start from a master action obtained by promoting the global shift invariance to a local one. We also obtain the mapping between the observables of the two equivalent theories. We show that the equivalence between the Maxwell-Chern-Simons theory and the self-dual model in commutative space-time does not survive in the non-commutative setting.Comment: 14 pages, typos correcte

Constraints from orbital motions around the Earth of the environmental fifth-force hypothesis for the OPERA superluminal neutrino phenomenology

It has been recently suggested by Dvali and Vikman that the superluminal neutrino phenomenology of the OPERA experiment may be due to an environmental feature of the Earth, naturally yielding a long-range fifth force of gravitational origin whose coupling with the neutrino is set by the scale M_*, in units of reduced Planck mass. Its characteristic length lambda should not be smaller than one Earth's radius R_e, while its upper bound is expected to be slightly smaller than the Earth-Moon distance (60 R_e). We analytically work out some orbital effects of a Yukawa-type fifth force for a test particle moving in the modified field of a central body. Our results are quite general since they are not restricted to any particular size of lambda; moreover, they are valid for an arbitrary orbital configuration of the particle, i.e. for any value of its eccentricity $e$. We find that the dimensionless strength coupling parameter alpha is constrained to |alpha| <= 1 10^-10-4 10^-9 for 1 R_e <= lambda <= 10 R_e by the laser data of the Earth's artificial satellite LAGEOS II, corresponding to M_* >= 4 10^9 -1.6 10^10. The Moon perigee allows to obtain |alpha| <= 3 10^-11 for the Earth-Moon pair in the range 15 R_e <= lambda = 3 10^10 - 4.5 10^10. Our results are neither necessarily limited to the superluminal OPERA scenario nor to the Dvali-Vikman model, in which it is M_* = 10^-6 at lambda = 1 R_e, in contrast with our bounds: they generally extend to any theoretical scenario implying a fifth-force of Yukawa-type.Comment: LaTex2e, 18 pages, 4 figures, 1 table, 81 reference

Fabrication of pre-structured substrates and growth of CIGS micro-absorbers

Second-generation thin-film Cu(In, Ga)Se2 (CIGS) solar cells are a well-established photovoltaic technology with a record power conversion efficiency of 23.6%. However, their reliance on critical raw materials, such as In and Ga, requires new approaches to reduce the amount of critical raw materials employed. The micro-concentrator concept involves the combination of thin-film photovoltaic technology with concentrator photovoltaic technology. This approach reduces the size of the solar cell to the micrometer range and uses optical concentration to collect sunlight from a larger area, focusing it onto micro solar cells. This work is devoted to the development of a process for manufacturing pre-structured substrates with regular arrays of holes with 200 and 250 μm diameters inside a SiOx insulating matrix. Subsequently, a Cu–In–Ga precursor is deposited by sputtering, followed by photoresist lift-off and the application of a Cu–In–Ga thermal annealing at 500 ◦C to improve precursor quality and assess pre-structured substrate stability under elevated temperatures. Finally, a two-stage selenization process leads to the formation of CIGS absorber micro-dots. This study presents in detail the fabrication process and explores the feasibility of a bottom-up approach using pre-structured substrates, addressing challenges encountered during fabrication and providing insights for future improvements in CIGS absorber materials.This research was funded by Fundação para a Ciência e a Tecnologia (FCT), PhD Scholarship number 2020.06063BD and partially funded by the UIDB/04650/2020 Strategic Project of the Physics Center of the University of Minho and Porto

Occurrence and seasonal variation of several endocrine disruptor compounds (pesticides, bisphenols, musks and UV-filters) in water and sediments from the estuaries of Tagus and Douro Rivers (NE Atlantic Ocean coast)

Funding Information: This work was supported by FEDER (Programa Operacional Competitividade e Internacionalização - COMPETE 2020), from PIDDAC through FCT/MCTES project POCI-01-0145-FEDER-028708-PTDC/ASP-PES/28708/2017 , by UIDB/04423/2020 and AgriFood XXI R&D&I project, operation No. NORTE-01-0145-FEDER-000041 , co-financed by the European Regional Development Fund (ERDF) through NORTH 2020 ( Northern Regional Operational Program 2014/2020 ). The Portuguese Foundation for Science and Technology (FCT) supported the contract of Sara C. Cunha (IF/01616/2015), the Ph.D. Grant of Isa Marmelo (DFA/BD/4413/2020) and the contract of Patrícia Anacleto (CEECIND/01739/2017). Other support was provided by the Laboratory of Ecotoxicology and Ecology, Department of Population Studies of the Institute of Biomedical Sciences of Abel Salazar (ICBAS) of the University of Porto , and by the Strategic Funding UIDB/Multi/04423/2019 , UIDB/04423/2020 and LA/P/0101/2020 through national funds provided by FCT and ERDF in the framework of the programme Portugal 2020 to CIIMAR. Publisher Copyright: © 2022 Elsevier B.V.Exposure of aquatic environments to emerging contaminants is a global issue, special relevant in many estuaries due to impacts from anthropogenic activity. The aim of this work was to evaluate thirty-seven endocrine disruptor chemicals (EDCs) from four different classes (pesticides, bisphenols, polycyclic musks and UV-filters) in water and sediment samples collected during one-year in the estuaries of Tagus and Douro Rivers located into the NE Atlantic Ocean coast. EDCs analysis was achieved afterward validation of a gas-chromatography mass spectrometry (GC–MS) method using Dispersive Liquid-Liquid Microextraction (DLLME) as extraction procedure for water samples, and Quick, Easy, Cheap, Efficient, Rugged and Safe (QuEChERS) combined with DLLME for sediments. Tagus estuary presented higher levels of contamination with pesticide residues and bisphenols (BPs) than the Douro estuary in both water and sediment samples. Contrariwise, levels and frequency of polycyclic musks (PCMs) and UV-filters (UVF) were slightly higher in Douro estuary. Levels of pesticide residues in both sediment and water samples, and levels of PCMs and UVF in water samples were higher in warmer seasons (summer and spring) than in colder ones (winter and autumn). The opposite was found in what respect levels of BPs in water and sediment samples, and PCMs and UVF levels in sediment samples. Although the levels found for each contaminant are low, usually in the order of a few ng/mL(g), the presence of a high number of toxic compounds is a source of concern and requires constant monitoring.publishersversionpublishe