Tensor renormalization group in bosonic field theory

We compute the partition function of a massive free boson in a square lattice using a tensor network algorithm. We introduce a singular value decomposition (SVD) of continuous matrices that leads to very accurate numerical results. It is shown the emergence of a CDL fixed point structure. In the massless limit, we reproduce the results of conformal field theory including a precise value of the central charge.Comment: 5+8 pages, 4+2 figure

Identification of students' mental models about the milk transformation in yogurt

A review of the scientific literature reveals that there are still few researches on the conceptions of secondary school students about chemical reactions involving microorganisms, especially those related to the mental models that students use in their explanations. This paper describes a study concerning the different mental models related to the milk transformation into yogurt with 83 students from a Spanish secondary school of 8th and 9th grade (13-16 years) developed in the framework of a research that intends to use the elaboration of this product as a context for the teaching and learning of chemical reactions through modeling approaches. In order to identify the mental models of the students, in this paper we consider the milk transformation into yogurt as a process in which its main components are: the entities involved (milk and bacteria), the interaction between them and the result (yogurt). A simplified school model of this process would involve students considering that bacteria use the sugar in milk to transform it into lactic acid through a chemical reaction to obtain the necessary energy. Using this scheme in interaction with the students' answers, the underlying mental models were identified. Although almost half of the students showed great difficulties explaining the process, five models have been identified. Students often consider the milk transformation into yogurt primarily as a physical process of agglutination or change of state. These models are far from a school model of reference in which the bacteria have a fundamental role in the transformation of milk into yogurt by a chemical reaction.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Phenomenology Tools on Cloud Infrastructures using OpenStack

We present a new environment for computations in particle physics phenomenology employing recent developments in cloud computing. On this environment users can create and manage "virtual" machines on which the phenomenology codes/tools can be deployed easily in an automated way. We analyze the performance of this environment based on "virtual" machines versus the utilization of "real" physical hardware. In this way we provide a qualitative result for the influence of the host operating system on the performance of a representative set of applications for phenomenology calculations.Comment: 25 pages, 12 figures; information on memory usage included, as well as minor modifications. Version to appear in EPJ

Standards for X-Ray Microanalysis of Calcified Structures

The ability of electron probe X-ray microanalysis (EPMA) to solve biological problems often depends on the use of a quantitative approach. EPMA allows the quantitative determination of chemical elements of biological materials by using reference standards which resemble the specimen in the mode of interaction with the electron beam. Although there is a large experience in the quantification of elements in biological thin specimens, experience with standards for X-ray microanalysis of bulk specimens is limited, especially for calcified structures where the density of the specimen is difficult to estimate. The quality of the results in EPMA depends on obtaining accurate calibration curves which allow the establishment of the relationship between the signal measured and the concentration of the element of interest. The different methods for specimen preparation and the thickness of the specimen will also determine the precise nature of the standardization technique to be adopted. The physics of the electron beam-specimen interactions impose limitations upon the accuracy of calibration, and the choice of an unstable standard can result in large errors in the quantification of elements. We have reviewed the different types of compounds that have been used as standards for biological EPMA of thin and bulk specimens and discuss their potential use for quantitative analysis of mineralized tissues, with special reference to otoconia, the calcified structures of the vestibular system

Integrability and scattering of the boson field theory on a lattice

A free boson on a lattice is the simplest field theory one can think of. Its partition function can be easily computed in momentum space. However, this straightforward solution hides its integrability properties. Here, we use the methods of exactly solvable models, that are currently applied to spin systems, to a massless and massive free boson on a 2D lattice. The Boltzmann weights of the model are shown to satisfy the Yang-Baxter equation with a uniformization given by trigonometric functions in the massless case, and Jacobi elliptic functions in the massive case. We diagonalize the row-to-row transfer matrix, derive the conserved quantities, and implement the quantum inverse scattering method. Finally, we construct two factorized scattering $S$ matrix models for continuous degrees of freedom using trigonometric and elliptic functions. These results place the free boson model in 2D in the same position as the rest of the models that are exactly solvable \`a la Yang-Baxter, offering possible applications in quantum computation.Comment: 32 pages, 4 figure

LEP and radiative electroweak breaking close the light gluino window

We show that the LEP lower bound on the chargino mass, in conjunction with the well motivated theoretical requirement of radiative electroweak symmetry breaking, imply an upper bound on the lightest Higgs boson mass (m_h\lsim62\GeV) in a supersymmetry breaking scenario where the gluino mass is a few GeV. Moreover, Higgs searches at LEP in the context of this model require m_h\gsim61\GeV. The remaining experimentally allowed region in the five-dimensional parameter space of this light gluino model is severely fine-tuned (with $\tan\beta=1.88-1.89$ and m_t=114.0-114.3\GeV) and cosmologically troublesome (with a neutralino relic abundance over {\it five-hundred times larger than allowed}). Modest improvements in sensitivity in LEP Higgs searches and Tevatron top-quark searches should soon exclude this theoretically disfavored model completely.Comment: 6 pages, no figures, tex (harvmac), CERN-TH.6890, CTP-TAMU-25/9

Location of franchises and large retail chains following the Great Recession. The case of the city of Zaragoza (Spain)

The current retail activity model is rapidly evolving, in order to adapt to consumer changes. For a long time, shopping centres have stood out as the most attractive model. However, the implementation of franchises and large commercial chains in cities is transforming the uses of urban space and configuring new spatial relationships. The city of Saragossa serves as a case study

Efecto inhibitorio in vitro de Solanum tuberosum (papa fermentada) comparado con vancomicina y oxacilina sobre cepas de Staphylococcus aureus

Introducción: Las enfermedades infecciosas frecuentes son causadas por bacterias piógenas, una de ellas es el Staphylococcus aureus, representa un peligro mortal para la humanidad. Esta bacteria coloniza normalmente al ser humano y tiene una gran capacidad adaptativa. Los fármacos antimicrobianos, utilizados para combatir estas infecciones suelen ocasionar efectos secundarios además de causar resistencia bacteriana, por lo que se debe buscar otras formas de tratamiento. Objetivo: Evaluar si existe efecto inhibitorio in vitro de Solanum tuberosum (papa fermentada) sobre cepas de Staphylococcus aureus comparado con vancomicina y oxacilina. Materiales y métodos: Se empleó el extracto acuoso del tocosh de Solanum tuberosum y una cepa de Staphylococcus aureus obtenida del laboratorio de Microbiología de la Universidad Nacional de Trujillo, la cual se enfrentó a 5 grupos, 3 de ellos con extractos al 25, 50 y 100% y 2 controles con oxacilina y vancomicina, para determinar la susceptibilidad antibacteriana por halos de inhibición y la concentración mínima inhibitoria (CMI) mediante el recuento de unidades formadoras de colonias. Resultados: Staphylococcus aureus fue muy sensible frente al extracto al 25% (17,75 ± 1,05 mm) y sumamente sensible frente a concentraciones del 50 % y 100% (22,17 ± 0,94 y 25,42 ± 1,62 mm respectivamente). La CMI fue de 500 mg /dL (extracto al 50%). Conclusión: Solanum tuberosum (papa fermentada) posee efecto inhibitorio in vitro sobre cepas de Staphylococcus aureus comparado con vancomicina y oxacilina.Introduction: Infectious diseases are caused by pyogenic bacterias. One of them is Staphylococcus aureus wich represents a mortal danger to humanity. This bacteria colonizes humans and has a great adaptive capacity. Antimicrobial drugs, posses side effects and can cause bacterial resistance, this is the reason why other forms of treatment must be search. Objective: To evaluate whether there is an in vitro inhibitory effect of Solanum tuberosum (fermented potato) on strains of Staphylococcus aureus compared to vancomycin and oxacillin.Materials and methods: The aqueous extracts of the starch of Solanum tuberosum and a strain of Staphylococcus aureus obtained from the Microbiology Laboratory of the National University of Trujillo were used, which was confronted with 5 groups, 3 of them with extracts at 25 , 50 and 100% and 2 controls with oxacillin and vancomycin to determine antibacterial susceptibility by inhibition halos and minimum inhibitory concentration (MIC) by counting colony forming units. Results: Staphylococcus aureus was very sensitive to the extract at 25% (17.75 ± 1.05 mm) and highly sensitive against concentrations of 50% and 100% (22.17 ± 0.94 and 25.42 ± 1, 62 mm respectively). The MIC was 500 mg / dL (50% extract). Conclusion: Solanum tuberosum (fermented potato) has an inhibitory effect in vitro on strains of Staphylococcus aureus compared to vancomycin and oxacillin.Tesi

An Analysis of Renewable Resource Development Alternatives for the Northern Arid Region of Mexico: Study Prospectus

In 1980, IIASA joined with the Centro de Investigation en Quimica Aplicada (CIQA) in order to study alternative production chains based on the renewable resources of the Northern Arid Region of Mexico. This study applied the "WELMM Approach" developed at IIASA. Its objective was to account for the basic resources used and processed along alternative production chains, from cultivation and harvesting of the plants to the final products. WELMM analyses of each of the production chains are now being completed, and IIASA and CIQA have decided to expand their cooperative efforts to include an analysis of alternative development projects for the Northern Arid Region based on these production chains. This paper presents a prospectus for the expanded study

Assessing the Potential Risks of Digital Therapeutics (DTX): The DTX Risk Assessment Canvas

Motivation: Digital therapeutics (DTX), i.e., health interventions that are provided through digital means, are increasingly available for use; in some countries, physicians can even prescribe selected DTX following a reimbursement by health insurances. This results in an increasing need for methodologies to consider and monitor DTX’s negative consequences, their risks to patient safety, and possible adverse events. However, it is completely unknown which aspects should be subject to surveillance given the missing experiences with the tools and their negative impacts. Objective: Our aim is to develop a tool—the DTX Risk Assessment Canvas—that enables researchers, developers, and practitioners to reflect on the negative consequences of DTX in a participatory process. Method: Taking the well-established business model canvas as a starting point, we identified relevant aspects to be considered in a risk assessment of a DTX. The aspects or building blocks of the canvas were constructed in a two-way process: first, we defined the aspects relevant for discussing and reflecting on how a DTX might bring negative consequences and risks for its users by considering ISO/TS 82304-2, the scientific literature, and by reviewing existing DTX and their listed adverse effects. The resulting aspects were grouped into thematic blocks and the canvas was created. Second, six experts in health informatics and mental health provided feedback and tested the understandability of the initial canvas by individually applying it to a DTX of their choice. Based on their feedback, the canvas was modified. Results: The DTX Risk Assessment Canvas is organized into 15 thematic blocks which are in turn grouped into three thematic groups considering the DTX itself, the users of the DTX, and the effects of the DTX. For each thematic block, questions have been formulated to guide the user of the canvas in reflecting on the single aspects. Conclusions: The DTX Risk Assessment Canvas is a tool to reflect the negative consequences and risks of a DTX by discussing different thematic blocks that together constitute a comprehensive interpretation of a DTX regarding possible risks. Applied during the DTX design and development phase, it can help in implementing countermeasures for mitigation or means for their monitoring