Chromoelectric fields and quarkonium-hadron interactions at high energies

We develop a simple model to study the heavy quarkonium-hadron cross section in the high energy limit. The hadron is represented by an external electric color field (capacitor) and the heavy quarkonium is represented by a small color dipole. Using high energy approximations we compute the relevant cross sections, which are then compared with results obtained with other methods. Our calculations are presented in a pedagogical way accessible to undergraduate students.Comment: To appear in Physical Review C, 24 pages, 10 eps figure

Uma adapta??o da Cifra de Hill para estudo de matrizes.

Programa de P?s-Gradua??o em Matem?tica em Rede Nacional. Departamento de Matem?tica, Instituto de Ci?ncias Exatas e Biol?gicas, Universidade Federal de Ouro Preto.Neste trabalho ser?o apresentados alguns dos principais resultados matem?ticos a respeito de Aritm?tica Modular, dando ?nfase ?s rela??es de equival?ncia e classes residuais. ? feito tamb?m um estudo sobre matrizes e suas propriedades operacionais; a fun??o determinante ? constru?da e apresentada como instrumento para o c?lculo de matrizes inversas. Tais temas s?o abordados com o intuito de fundamentar os processos matem?ticos aplicados para funcionamento da Cifra de Hill. Essa cifra ? um dos m?todos de criptografia apresentados neste texto e ao qual daremos destaque. Para finalizar, foi desenvolvida uma atividade voltada para turmas do Ensino M?dio e baseada na Cifra de Hill, cujo principal objetivo ? despertar o interesse dos alunos para o estudo de matrizes.In this paper, some of the main mathematical results will be presented about Modular Arithmetic, emphasizing the relations of equivalence and residue classes. Besides, a study on matrices and their operational properties; the determinant function is constructed and presented as an instrument for the calculation of inverse matrices. These themes are approached in order to base the mathematical processes applied to the operation of the Hill Cipher. This cipher is one of the cryptographic methods presented in this text and we will highlight it. To conclude, an activity was developed, focused on high school classes and based on Hill Cipher, which main objective is to arouse students? interest in studying matrices

Uma adapta??o da Cifra de Hill para estudo de matrizes.

Neste artigo ser?o apresentados alguns dos principais resultados matem?ticos a respeito de Aritm?tica Modular, dando ?nfase ?s rela??es de equival?ncia e classes residuais, al?m de alguns fatos sobre matrizes em Zp. Tais temas s?o abordados com o intuito de fundamentar os processos matem?ticos aplicados para funcionamento da Cifra de Hill, que ? um modelo de criptografia utilizado como inspira??o para o desenvolvimento de uma atividade voltada para turmas de Ensino M?dio

Identification and analysis of errors in the preparation of drugs in a pediatric hospital unit

Este estudo objetivou identificar e analisar os erros no preparo de medicamentos em unidade pedi?trica de uma institui??o hospitalar. Trata-se de estudo descritivo, realizado com quatro profissionais respons?veis pelo preparo dos medicamentos de um hospital do interior do Estado de Minas Gerais, que foram submetidos ? t?cnica de observa??o estruturante e formul?rio. Utilizou-se a an?lise descritiva junto aos dados. Como resultados, destacam-se a inexist?ncia de diretrizes para o preparo de medicamentos, presen?a de interrup??es durante o processo, n?o utiliza??o das t?cnicas de lavagem das m?os e de desinfec??o de frascos e ampolas. Faz-se necess?ria a conscientiza??o dos profissionais para a ocorr?ncia e consequ?ncias dos erros cometidos pela equipe, como forma de est?mulo para a preven??o dos mesmos, atrav?s de pr?ticas seguras e efetivas, a fim de ampliar a qualidade da assist?ncia.Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)Empresa de Pesquisa Agropecu?ria de Minas Gerais (EPAMIG)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)This study aimed to identify and analyze errors in the preparation of medicines in the pediatric unit of a hospital. This descriptive study was performed with 04 professionals responsible for preparation of medicines developed in a hospital in the interior of Minas Gerais, Brasil, that were submitted to the technique of structural observation and formulary. A descriptive analysis of the data was performed. The results highlight the lack of guidelines for the preparation of drugs, presence of interruptions during the process failure of utilization of recommended hand washing techniques, and disinfection of bottles and vials. It is necessary to make professionals aware of the occurrence and consequences of the main mistakes made by the team, as a stimulus for prevention through safe and effective practices to improve the quality of care

Entanglement study of the 1D Ising model with Added Dzyaloshinsky-Moriya interaction

We have studied occurrence of quantum phase transition in the one-dimensional spin-1/2 Ising model with added Dzyaloshinsky-Moriya (DM) interaction from bi- partite and multi-partite entanglement point of view. Using exact numerical solutions, we are able to study such systems up to 24 qubits. The minimum of the entanglement ratio R $\equiv$ \tau 2/\tau 1 < 1, as a novel estimator of QPT, has been used to detect QPT and our calculations have shown that its minimum took place at the critical point. We have also shown both the global-entanglement (GE) and multipartite entanglement (ME) are maximal at the critical point for the Ising chain with added DM interaction. Using matrix product state approach, we have calculated the tangle and concurrence of the model and it is able to capture and confirm our numerical experiment result. Lack of inversion symmetry in the presence of DM interaction stimulated us to study entanglement of three qubits in symmetric and antisymmetric way which brings some surprising results.Comment: 18 pages, 9 figures, submitte

Impact of extreme weather events frequency and intensity in shaping phytoplankton communities

Lake habitats and communities can often be correlated with general morphometric and geographic characteristics such as depth, latitude, altitude, or watershed area. Further, communities are typically correlated with average environmental conditions such as seasonal temperature and nutrient levels. The frequency and intensity of extreme weather events (rain and wind) are typically not encompassed by average environmental descriptors, yet, can modify the physical habitats of lakes, significantly influencing phytoplankton growth and survival. We tested the hypothesis that lakes with a higher frequency and intensity of extreme weather events have a functionally different phytoplankton assemblage from lakes with a lower frequency of extreme weather events. We compiled long-term (mean = 20±13 years, range 0.6-44 years) phytoplankton datasets for 22 lakes across a wide gradient of altitude, latitude, depth, and trophic state. We classified the phytoplankton genera into morpho-functional groups and C-S-R strategists, and compared among lake phytoplankton assemblages’ characteristics across the gradient of wind and rain conditions experienced by the lakes. We discuss how the frequency of extreme weather events can affect phytoplankton functional groups, the dominance of differing life history strategies and ultimately community structure. The frequency and intensity of extreme events is expected to increase with climate change, with the potential to drive shifts in phytoplankton composition

Separability and entanglement in 2x3xN composite quantum systems

The separability and entanglement of quantum mixed states in \Cb^2 \otimes \Cb^3 \otimes \Cb^N composite quantum systems are investigated. It is shown that all quantum states $\rho$ with positive partial transposes and rank $r(\rho)\leq N$ are separable.Comment: Latex, 15 page

A global dataset on weather, lake physics, and phytoplankton dynamics

We compiled data from over 30 lakes across the globe to address how storms influence thermal structure and phytoplankton community dynamics mediated by lake conditions and functional traits. In addition to (generally) fortnightly phytoplankton samples (mean ± SD temporal coverage across all lakes = 20 ± 13 years), the dataset includes limnological variables from standard long-term monitoring programs (24 ± 15 years coverage), daily weather observations (16 ± 10 years coverage) and, when available, high-frequency lake water temperature and water chemistry profiles (12 ± 7 years coverage). All data have been standardized to similar formats and include complete metadata. We used the dataset to develop an R-package (“algaeClassify”), which assigns phytoplankton genus/species information to multiple functional trait groups, and here we provide a summary of ongoing research using the dataset to investigate: 1) the influence of storm events on seasonal phytoplankton succession, 2) the impact of storms on lake thermal structure, and 3) whether lake phytoplankton communities are shaped by long-term patterns in disturbance frequency and intensity. We give an overview on how to access these data, and we further highlight the opportunities the dataset provides for asking both basic and applied questions in limnology, ecology, climate change, and lake management

Decision Making with Asymmetric Information

Every day individuals make numerous choices. What is important for making the right choice is that individuals have good information about the consequences of the different alternatives. However, investigating the full consequences of the different alternatives is complicated and costly. Consequently, individuals sometimes do not possess all relevant information to take a decision. This thesis discusses models in which an agent decides whether or not to perform a task on behalf of the principal. A key element in the models we consider is incomplete and asymmetric information. Broadly, the thesis can be split up into two parts. The first part of the thesis deals with models in which the principal is better informed than the agent. The agent has to decide whether or not to perform a task, but lacks information about his ability. We analyze how the agent makes a self-assessment of his ability, based on appraisals of others (the principal) and experience. Based on this self-assessment the agent takes a decision. The second part of the thesis deals with models in which the agent is better informed than the principal. On behalf of the principal the agent takes a decision about a project. Sometimes agents do not act in the interest of the principal. We analyze how the principal can use retention contracts to discipline the agent. In the remainder of the Introduction we discuss the two parts of the thesis and we provide an overview of the chapters of this thesis