Eikonal Approximation to 5D Wave Equations as Geodesic Motion in a Curved 4D Spacetime

We first derive the relation between the eikonal approximation to the Maxwell wave equations in an inhomogeneous anisotropic medium and geodesic motion in a three dimensional Riemannian manifold using a method which identifies the symplectic structure of the corresponding mechanics. We then apply an analogous method to the five dimensional generalization of Maxwell theory required by the gauge invariance of Stueckelberg's covariant classical and quantum dynamics to demonstrate, in the eikonal approximation, the existence of geodesic motion for the flow of mass in a four dimensional pseudo-Riemannian manifold. These results provide a foundation for the geometrical optics of the five dimensional radiation theory and establish a model in which there is mass flow along geodesics. Finally we discuss the case of relativistic quantum theory in an anisotropic medium as well. In this case the eikonal approximation to the relativistic quantum mechanical current coincides with the geodesic flow governed by the pseudo-Riemannian metric obtained from the eikonal approximation to solutions of the Stueckelberg-Schr\"odinger equation. This construction provides a model for an underlying quantum mechanical structure for classical dynamical motion along geodesics on a pseudo-Riemannian manifold. The locally symplectic structure which emerges is that of Stueckelberg's covariant mechanics on this manifold.Comment: TeX file. 17 pages. Rewritten for clarit

Casimir forces in Bose-Einstein condensates: finite size effects in three-dimensional rectangular cavities

The Casimir force due to {\it thermal} fluctuations (or pseudo-Casimir force) was previously calculated for the perfect Bose gas in the slab geometry for various boundary conditions. The Casimir pressure due to {\it quantum} fluctuations in a weakly-interacting dilute Bose-Einstein condensate (BEC) confined to a parallel plate geometry was recently calculated for Dirichlet boundary conditions. In this paper we calculate the Casimir energy and pressure due to quantum fluctuations in a zero-temperature homogeneous weakly-interacting dilute BEC confined to a parallel plate geometry with periodic boundary conditions and include higher-order corrections which we refer to as Bogoliubov corrections. The leading order term is identified as the Casimir energy of a massless scalar field moving with wave velocity equal to the speed of sound in the BEC. We then obtain the leading order Casimir pressure in a general three-dimensional rectangular cavity of arbitrary lengths and obtain the finite-size correction to the parallel plate scenario.Comment: 12 pages; no figures; v.2: version accepted for publication in JSTAT v.3: references adde

Pengaruh Sistem Kontrol Solar Cell Berbasis Timer Dengan Acuan Pergerakan Matahari

AbstrakKrisis energi menjadi permasalahan yang sangat besar dan perlu perhatian khusus oleh dunia khususnya untuk negara Indonesia. Energi listrik khusunya yang amat berpengaruh terhadap keberlangsungan hidup manusia saat ini. Peningkatan kebutuhan energi listrik rata 2,2 % pertahun mengakibat listrik sangat perlu diperhatikan, solusi terbaik dengan membuat energi alternatif. Salah satu energi alternatif yang dapat mengatasi kebutuhan energi listrik adalah energi panas matahari, yakni dengan menggunakan solar cell untuk mengubah energi panas matahari menjadi energi listrik. tujuannya dari penelitian ini yaitu mencari performa terbaik dari solar cell, Solusi untuk menambah daya dan efisiensi solar cell dengan penelitian menggunakan metode eksperimental dimana solar cell akan di tambahkan sistem kontrol dengan basis timer sebagai agar dapat mengikuti pergerakan sinar matahari dari pagi hingga sore hari, dengan variasi waktu yang berbeda. Penelitian ini dilakukan dengan menggunakan metode eksperimental dimana solar cell akan dikontrol menjadi sistem solar cell yang mampu mengitkuti pergerakan matahari. Teknik analisa data dalam penelitian ini menggunakan analisis data deskriptif yaitu menggambarkan hasil penelitian dalam bentuk tabel dan grafik. Tujuan dari penelitian ini adalah untuk mengetahui performa solar cell yang menggunakan sistem kontrol berbasis timer dengan acuan pergerkan matahari. Penelitian tentang sistem kontrol solar cell berbasis timer yang dilakukan diharapkan, dapat memperoleh nilai efisiensi solar cell yang tinggi. Penelitian sistem kontrol solar cell berbasis Timer ini memiliki variabel rentang waktu pengambilan selama 15 menit, 30 menit, dan 60 menit. Berdasarkan data pengujian penggunaan variabel terbaik terbaik terdapat pada penggunaan waktu pengambilan selama 15 menit, dikarenakan memiliki nilai persentase efisiensi tertinggi yaitu sebesar 9.62%, dibandingkan dengan variabel rentang waktu pengambilan 30 menit yaitu 9,46% dan rentang waktu 60 menit yaitu 9,23%. Berdasarkan data pengujian semakin kecil rentang waktu pengambilan maka akan berpengaruh terhadap kenaikan efisiensi solar cell. Karena pergerakan solar cell yang di peroleh akan lebih banyak sehingga lebih mengikuti gerak matahari pada setiap harinya.Kata kunci: Kata kunci : Solar Cell, Timer, Efisiensi.Abstract Energy crisis becomes a big problem and need special attention by the world especially for the country of Indonesia. Electric energy is especially influential on the survival of human life today. Increasing the need of electric energy average 2.2% per year due to electricity needs to be considered, the best solution by making alternative energy. One alternative energy that can overcome the need for electrical energy is solar thermal energy, namely by using solar cells to convert solar thermal energy into electrical energy. the goal of this research is to find the best performance from solar cell, Solution to increase power and efficiency of solar cell with research using experimental method where solar cell will be added control system with base timer as to follow the movement of sunshine from morning until afternoon, with different time variations. This research was conducted by using experimental method where solar cell will be controlled to solar cell system capable of mengitkuti movement of the sun. Data analysis techniques in this study using descriptive data analysis that describes the results of research in the form of tables and graphs. The purpose of this research is to know the performance of solar cell that uses timer based control system with the reference of sun movement. Research on solar cell-based control system that is done is expected, can get high efficiency value of solar cell. The research of Timer based solar cell control system has variable of taking time for 15 minutes, 30 minutes, and 60 minutes. Based on the test data the best use of the best variables is found in the use of the retrieval time for 15 minutes, because it has the highest efficiency percentage value of 9.62%, compared with the 30 minute retrieval time variable is 9.46% and the time span 60 minutes is 9.23% . Based on test data the smaller the retrieval time it will affect the increase in solar cell efficiency. Because the movement of solar cells in the gain will be more so that more follow the motion of the sun on each day. Keywords: Solar Cell, Timer,Efficiency

El nacimiento del Estado Plurinacional de Bolivia, la crisis y la integración regional

Bolivia, during 2008, became a propitious scenario for a coup d'état. A South American nation that was undertaking profound transformations of the status quo, in favor of the inclusion of historically neglected social sectors, saw its democratic institutions put in check by opposition movements. With the study of the founding process of the Movement to Socialism (MAS), the distribution of the actors' capacities in the Bolivian political system and the parameters of the conflict as a starting point, this paper analyses the role that the Union of South American Nations (Unasur) played in the institutional crisis. To do so, it takes as a basis the analysis of primary sources, i.e. documents issued by official bodies of the Bolivian state, as well as declarations and reports from the regional integration bloc. To this end, contributions from the thinking of Bolivian sociologist René Zavaleta Mercado were used, with the aim of theoretically interpreting the specificities of recent Bolivian history. This work verifies a relationship between the construction of Unasur as a space for dialogue and political agreement, and that it was able to resolve the crisis.Bolivia, durante el 2008, se convirtió en un escenario propicio para un golpe de Estado. Una nación sudamericana que emprendía profundas transformaciones del statu quo, en favor de la inclusión de sectores sociales históricamente postergados, veía sus instituciones democráticas puestas en jaque por movimientos opositores. Con el estudio del proceso fundacional del Movimiento al Socialismo (MAS), de la distribución de las capacidades de los actores en el sistema político boliviano y de los parámetros del conflicto como punto de partida, el presente trabajo analiza el rol que tuvo la Unión de las Naciones Suramericanas (Unasur) en la crisis institucional. Para ello, se toma como base el análisis de fuentes primarias, es decir, documentos emitidos por órganos oficiales del Estado boliviano, así como declaraciones e informes del bloque de integración regional. Para tal efecto, se emplearon contribuciones del pensamiento del sociólogo boliviano René Zavaleta Mercado, con el objetivo de interpretar teóricamente las especificidades de la historia reciente boliviana.Este trabajo verifica una relación entre la construcción de Unasur como espacio de diálogo y concertación política, y la crisis que fue capaz de resolver

Role of Neonatal Biomarkers of Exposure to Psychoactive Substances to Identify Maternal Socio-Demographic Determinants

Simple summary: the rapid identification of newborns exposure to psychoactive drugs allows an appropriate clinical care. this study tried to identify maternal profiles that help to identify newborns exposed to psychoactive drugs during pregnancy. mothers were interviewed using a questionnaire. The biomarkers of fetal exposure were measured in meconium samples. statistical analysis was performed to identify the maternal characteristics that were most likely to be associated with drug use during pregnancy. of a total of 372 mothers, 49 (13.2%) tested positive for psychoactive drugs use: 24 (49.0%) for cannabis, 11 (22.5%) for ethyl glucuronide, six (12.2%) for cocaine, and eight (16.3%) for more than one psychoactive substance. the maternal characteristics that most likely identify substance use during pregnancy are: maternal age < 24 years, lack of pregnancy care, single-mother families, and active tobacco smoking. the profiles of prenatal maternal exposure identified in a clinical setting can be used to request specific detection tests for identifying newborns exposed to these drugs.Background: the accurate assessment of fetal exposure to psychoactive substances provides the basis for appropriate clinical care of neonates. the objective of this study was to identify maternal socio-demographic profiles and risk factors for prenatal exposure to drugs of abuse by measuring biomarkers in neonatal matrices. methods: a prospective, observational cohort study was completed. Biomarkers of fetal exposure were measured in meconium samples. The mothers were interviewed using a questionnaire. univariate and multivariate logistic regression analyses were performed. results: a total of 372 mothers were included, 49 (13.2%) testing positive for psychoactive substances use: 24 (49.0%) for cannabis, 11 (22.5%) for ethyl glucuronide, six (12.2%) for cocaine, and in eight (16.3%) more than one psychoactive substance. mothers who consumed any psychoactive substance (29.7 +/- 6.6 years) or cannabis (27.0 +/- 5.7 years) were younger than non-users (32.8 +/- 6.2 years, p < 0.05). cocaine (50.0% vs. 96.9%, p < 0.05) and polydrug users (37.5% vs. 96.9%, p < 0.05) showed a lower levels of pregnancy care. Previous abortions were associated with the use of two or more psychoactive substances (87.5% vs. 37.8%, p < 0.05). Single-mother families (14.3% vs. 2.5%, p < 0.05) and mothers with primary level education (75.5% vs. 55.1%, p < 0.05) presented a higher consumption of psychoactive substances. Independent risk factors that are associated with prenatal exposure include: maternal age < 24 years (odds ratio: 2.56; 95% CI: 1.12-5.87), lack of pregnancy care (odds ratio: 7.27; 95%CI: 2.51-21.02), single-mother families (odds ratio: 4.98; 95%CI: 1.37-8.13), and active tobacco smoking (odds ratio: 8.13; 95%CI: 4.03-16.43). conclusions: these results will allow us to develop several risk-based drug screening approaches to improve the early detection of exposed neonates

Evaluación de daños e inundaciones costeras bajo proyecciones de aumento del nivel del mar: un estudio de caso en San Francisco de Campeche, México

The city of San Francisco de Campeche, located in the Yucatan Peninsula, Mexico, is vulnerable to coastal flooding due to its geographical location and low altitude terrain. Under these inherent site conditions, sea level rise associated with climate change represents a potential threat to people\u27s property and goods in the coming decades. In this work, three scenarios of sea level rise in the coastal area of the city of San Francisco de Campeche were evaluated through numerical simulation and using wave and wind data obtained from the ERA5 reanalysis model as inputs: astronomical tide data and a high-resolution topobathymetric model. The scenarios evaluated correspond to the periods 2031-2050, 2046-2065, and 2081-2100 reported in the latest IPCC assessment report. Damage to people\u27s property and goods was analyzed using the CENAPRED methodology based on the type of housing. The results allow identifying that the area of the old neighborhood of San Román, Colonia Miramar, Pedro Sainz de Baranda, Adolfo Ruiz Cortinez, Resurgimiento avenues, and the Campeche-Merida and Campeche-Champoton coastal highway, as well as the federal and state government offices they will be the most affected areas by sea level rise with economic damages exceeding $13,860,322 Mexican pesos ($USD 805,832.67) under the 2031-2050 scenario, $14,706,754  Mexican pesos ($USD 855,043.83) in the 2046-2065 scenario and $22,536,250 Mexican pesos ($USD 1,310,247.09) in the 2081-2100 scenario; and the Los Petenes Biosphere Reserve as one of the ecological zones with the greatest extension of flooding; as well as downtown areas of the city that currently have residential, commercial, recreational, and port uses. Considering the three scenarios and effects on the population and housing, the 2081-2100 scenario is the one that generates the greatest flooding and with it a greater economic loss that exceeds 12 million dollars compared to the 2046-2050 scenario.La ciudad de San Francisco de Campeche, ubicada en la Península de Yucatán, México; es vulnerable a inundaciones costeras debido a su ubicación geográfica y terreno de baja altitud. Bajo estas condiciones inherentes al sitio, el aumento del nivel del mar asociado con el cambio climático representa una amenaza potencial a las propiedades y bienes de las personas en las próximas décadas. En este trabajo se evaluaron tres escenarios de aumento del nivel del mar en la zona costera de la ciudad de San Francisco de Campeche mediante simulación numérica y utilizando como insumos datos de oleaje y viento obtenidos del modelo de reanálisis ERA5, datos de mareas astronómicos y un modelo topobatimétrico de alta resolución. Los escenarios evaluados corresponden a los períodos 2031-2050, 2046-2065 y 2081-2100 reportados en el último informe de evaluación del IPCC. Los daños a las propiedades y bienes de las personas se analizaron mediante la metodología del CENAPRED según el tipo de vivienda. Los resultados permiten identificar que el área del antiguo barrio de San Román, la Colonia Miramar, las avenidas Pedro Sainz de Baranda, Adolfo Ruiz Cortínez, Resurgimiento y la carretera costera Campeche-Mérida y Campeche-Champotón, así como las oficinas del gobierno federal y estatal serán las zonas más afectadas por el aumento del nivel del mar con daños económicos superiores a los $13,860,322 pesos mexicanos ($USD 805,832.67) en el escenario 2031-2050, $14,706,754 pesos mexicanos ($USD 855,043.83) en el escenario 2046-2065 y $22,536,250 pesos mexicanos ($USD 1.310.247,09) en el escenario 2081-2100; y la Reserva de la Biosfera Los Petenes como una de las zonas ecológicas con mayor extensión de inundaciones; así como zonas céntricas de la ciudad que actualmente tienen usos residenciales, comerciales, recreativos y portuarios. Considerando los tres escenarios y efectos sobre la población y la vivienda, el escenario 2081-2100 es el que genera mayores inundaciones y con ello una mayor pérdida económica que supera los 12 millones de dólares respecto al escenario 2046-2050

Solar Advanced Oxidation Processes as disinfection tertiary treatments for real wastewater: implications for water reclamation.

The aim of this study was to assess the disinfection of a real secondary effluent from a municipal wastewater treatment plant using added H2O2 (20 and 50 mg L???1), TiO2 (100 mg L???1) and photo-Fenton under natural solar radiation in compound parabolic collector photo-reactors. For this purpose, the naturally occurring Escherichia coli, spores of sulphite-reducing clostridia (SRC), somatic coliphages (SOMCPH) and F-specific RNA bacteriophages (FRNA) were tested before and along the different solar treatments. Results for E. coli showed the different treatments efficiency rank: photo-Fenton pH 3 > H2O2 (20 mg L???1)/solar > TiO2/solar > solar photo-inactivation. On the other hand, for viral indicators the ranking was: photo-Fenton pH 3 > TiO2/solar > H2O2 (20 mg L???1)/solar > solar photo-inactivation. SRC was the most resistant indicator microorganism in all the evaluated processes. For the first time these solar processes have been evaluated for naturally occurring conventional indicators such as E. coli and alternative indicators such as SOMCPH and FRNA as viral indicators or spores of SRC as protozoan indicators. Some of the tested solar photo-oxidation treatments have shown their capability to reduce E. coli concentrations to a suitable level for water reuse (according to different reclaimed water guidelines) within affordable treatment times

Pre-analytical and analytical variables affecting the measurement of plasma-derived microparticle tissue factor activity

Elevated levels of tissue factor positive (TF+) microparticles (MPs) are observed in plasma from a variety of patients with an increased risk of thrombosis. We and others have described the measurement of TF activity in MPs isolated from plasma. The aim of this study was to investigate the effects of pre-analytical and analytical variables on TF activity of MPs isolated from blood of healthy volunteers treated ex vivo with or without bacterial lipopolysaccharide

Identification and trace level determination of brominated flame retardants by liquid chromatography/quadrupole linear ion trap mass spectrometry

We describe the development of instrumental methodology for the simultaneous determination of hexabromocyclododecane (HBCD) diastereoisomers and tetrabromobisphenol A (TBBPA) and its derivatives by liquid chromatography/quadrupole linear ion trapmass spectrometry (LC-QqLIT-MS). Two different experiments were developed, optimized and compared. The first is based on a selected reaction monitoring (SRM)method inwhich the twomost abundant transitions were selected for each analyte, as well as for the internal standards. In the second, the ion trap was used for the storage and subsequent fragmentation of precursor ions, obtaining an enhanced product ion (EPI) experiment. Both methods were validated by measuring quality parameters such as linearity, sensitivity, repro- ducibility and repeatability. Limits of detection (LODs) were in the range of 0.1???1.8 pg and 0.01???0.5 pg for SRM and EPI experiments, respectively, being lower than those published for the LC/QqQ-MS methods. Thus, LC-QqLIT-MS, used for quantification and confirmation, proved to be a powerful and very sensitive analytical tool