Particle statistics and lossy dynamics of ultracold atoms in optical lattices

Experimental control over ultracold quantum gases has made it possible to investigate low-dimensional systems of both bosonic and fermionic atoms. In closed one-dimensional systems there are many similarities in the dynamics of local quantities for spinless fermions and strongly interacting "hard-core" bosons, which on a lattice can be formalized via a Jordan-Wigner transformation. In this study, we analyze the similarities and differences for spinless fermions and hard-core bosons on a lattice in the presence of particle loss. The removal of a single fermion causes differences in local quantities compared with the bosonic case because of the different particle exchange symmetry in the two cases. We identify deterministic and probabilistic signatures of these dynamics in terms of local particle density, which could be measured in ongoing experiments with quantum gas microscopes

A herança estruturalista de Durkheim nas ciências sociais

The article discusses the assimilation of some aspects of Durkheim’s structuralism by Bourdieu and Lévi-Strauss. In Durkheim’s view, the fundamental categories of human thinking are socially built, due to the ontological priority of the collective. These categories seem to be structured in opposing pairs. Bourdieu admits that this type of categories is at the basis of the construction of the social space and habitus, even in contemporary societies. Although Lévi-Strauss disagrees with Durkheim in terms of problems and hypotheses, he is in accordance with him on the assumptions of structuralism. He admits, for instance, that the totemic structure of opposing pairs is a universal category. Key words: Durkheim, structuralism, category, totemism.Explica a assimilação de aspectos do estruturalismo de Durkheim por Bourdieu e Lévi- Strauss. Para Durkheim, as categorias fundamentais do pensamento seriam socialmente construídas, em função da superioridade ontológica do coletivo. Estas categorias teriam a estrutura de pares opostos. Bourdieu admite que este padrão está tanto na base da construção do espaço social quanto do habitus, mesmo nas sociedades contemporâneas. E Lévi-Strauss, ainda que divirja de Durkheim nos problemas e nas hipóteses, está de acordo com ele quanto aos pressupostos do estruturalismo. Chega a conceder que a estrutura totêmica, de pares opostos, seja um padrão universal. Palavras-chave: Durkheim, estruturalismo, categoria, totemismo

A herança estruturalista de Durkheim nas ciências sociais

The article discusses the assimilation of some aspects of Durkheim’s structuralism by Bourdieu and Lévi-Strauss. In Durkheim’s view, the fundamental categories of human thinking are socially built, due to the ontological priority of the collective. These categories seem to be structured in opposing pairs. Bourdieu admits that this type of categories is at the basis of the construction of the social space and habitus, even in contemporary societies. Although Lévi-Strauss disagrees with Durkheim in terms of problems and hypotheses, he is in accordance with him on the assumptions of structuralism. He admits, for instance, that the totemic structure of opposing pairs is a universal category. Key words: Durkheim, structuralism, category, totemism.Explica a assimilação de aspectos do estruturalismo de Durkheim por Bourdieu e Lévi- Strauss. Para Durkheim, as categorias fundamentais do pensamento seriam socialmente construídas, em função da superioridade ontológica do coletivo. Estas categorias teriam a estrutura de pares opostos. Bourdieu admite que este padrão está tanto na base da construção do espaço social quanto do habitus, mesmo nas sociedades contemporâneas. E Lévi-Strauss, ainda que divirja de Durkheim nos problemas e nas hipóteses, está de acordo com ele quanto aos pressupostos do estruturalismo. Chega a conceder que a estrutura totêmica, de pares opostos, seja um padrão universal. Palavras-chave: Durkheim, estruturalismo, categoria, totemismo

Confined cell migration and asymmetric hydraulic environments to evaluate the metastatic potential of cancer cells

Metastasis, a hallmark of cancer development, is also the leading reason for most cancer-related deaths. Furthermore, cancer cells are highly adaptable to microenvironments and can migrate along pre-existing channel-like tracks of anatomical structures. However, more representative three-dimensional models are required to reproduce the heterogeneity of metastatic cell migration in vivo to further understand the metastasis mechanism and develop novel therapeutic strategies against it. Here, we designed and fabricated different microfluidic-based devices that recreate confined migration and diverse environments with asymmetric hydraulic resistances. Our results show different migratory potential between metastatic and nonmetastatic cancer cells in confined environments. Moreover, although nonmetastatic cells have not been tested against barotaxis due to their low migration capacity, metastatic cells present an enhanced preference to migrate through the lowest resistance path, being sensitive to barotaxis. This device, approaching the study of metastasis capability based on confined cell migration and barotactic cell decisions, may pave the way for the implementation of such technology to determine and screen the metastatic potential of certain cancer cells

Papel de la calidad de la grasa de la dieta sobre los niveles postprandiales de secretina, colecistoquinina y polipéptido pancreático en humanos

The effects of adaptation to two diets differing in the type of dietary fat on the circulating levels of secretin, cholecystokinin, and pancreatic polypeptide, were investigated in humans. A relationship with the results concerning gastric acid secretion and gastrin release previously described by us, was also examined. The study in volved 18 cholecystectomized subjects previously submitted to a 30-day adaptation period to diets containing olive (group O) or sunflower oil (group S) as the main fat source. During the experimental period, physiological stimulation was achieved by ingestion of 200 mL oleic acid- (group O) or linoleic acid enriched (group S) liquid mixed meals. Food ingestion did not induce no significant changes in plasma secretin concentration in any of the groups, and no signijicant differences were observed between them for basal and postprandial situations. Plasma cholecystokinin le veIs were signijicantly higher in group O throughout the 30-120 min postprandial periodo The type of dietary fat affected the pancreatic polypeptide response to food, since values in group O were significantly higher than in group S at any point during the postprandial period, thus, despite of significant release in both grollps after the meal. lt is suggested that endogenous cholecystokinin may be responsible for the attenuated gastric acid secretory response and the suppression of serum gastrin previously observed in the subjects of group O, through a somatostatin-mediated (paracrine) or peptide YY-mediated (endocrine) mechanism. Secretin does not seem to be in volved in the fat-induced inhibition of human gastric acid secretion, and a role for pancreatic polypeptide is doubtful.Los efectos de la adaptación a dos dietas que diferían en el tipo de grasa, sobre los niveles circulantes de secretina, colecistoquinina y polipéptido pancreático fueron investigados en humanos. También fue examinada la relación, previamente descrita por nosotros, con los resultados que concernían a la secreción de ácido gástrico y la liberación de gastrina. El estudio incluyó a 18 sujetos colecistectomizados previamente sometidos a un período de adaptación de 30 días a dietas que contenían aceite de oliva (grupo O) o de girasol (grupo G) como fuente de grasa principal. Durante el periodo experimental, la estimulación fisiológica se consiguió mediante la ingestión de 200 mi de ácido oleico (grupo O) o aceite de girasol (grupo S) mezclados con la comida. La ingestión de la dieta no indujo cambios significativos sobre la concentración en plasma de secretina en ninguno de los dos grupos, tampoco fueron observadas diferencias significativas entre dicha concentración plasmática en situaciones basal y postprandial. Los niveles plasmáticos de colecistoquinina fueron significativamente mayores en el grupo O durante un periodo postprandial de 30-120 minutos. El tipo de grasa de la dieta afectó a la respuesta del polipéptido pancreático a la comida, los valores en el grupo O fueron significativamente mayores a los del grupo S en cualquier punto durante el período postprandial, a pesar de la significativa liberación en ambos grupos tras la comida. Se sugirió que la colecistoquinina endógena podría ser responsable de la atenuación de la repuesta secetora de ácido gástrico y de la supresión de la serina sérica previamente observada en los sujetos del grupo O, a través dee un mecanismo mediado por somatostatina (paracrino) o por péptido YY (endocrino). La secretina no parece estar implicada en la inhibición inducida por la grasa de la secreción gástrica en humanos, y es dudoso el papel atribuido al polipéptido pancreático

SubHaloes going Notts: The SubHalo-Finder Comparison Project

We present a detailed comparison of the substructure properties of a single Milky Way sized dark matter halo from the Aquarius suite at five different resolutions, as identified by a variety of different (sub-)halo finders for simulations of cosmic structure formation. These finders span a wide range of techniques and methodologies to extract and quantify substructures within a larger non-homogeneous background density (e.g. a host halo). This includes real-space, phase-space, velocity-space and time- space based finders, as well as finders employing a Voronoi tessellation, friends-of-friends techniques, or refined meshes as the starting point for locating substructure.A common post-processing pipeline was used to uniformly analyse the particle lists provided by each finder. We extract quantitative and comparable measures for the subhaloes, primarily focusing on mass and the peak of the rotation curve for this particular study. We find that all of the finders agree extremely well on the presence and location of substructure and even for properties relating to the inner part part of the subhalo (e.g. the maximum value of the rotation curve). For properties that rely on particles near the outer edge of the subhalo the agreement is at around the 20 per cent level. We find that basic properties (mass, maximum circular velocity) of a subhalo can be reliably recovered if the subhalo contains more than 100 particles although its presence can be reliably inferred for a lower particle number limit of 20. We finally note that the logarithmic slope of the subhalo cumulative number count is remarkably consistent and <1 for all the finders that reached high resolution. If correct, this would indicate that the larger and more massive, respectively, substructures are the most dynamically interesting and that higher levels of the (sub-)subhalo hierarchy become progressively less important.Comment: 16 pages, 7 figures, 2 tables, Accepted for MNRA

Arsenic Trioxide with Ascorbic Acid and High-Dose Melphalan: Results of a Phase II Randomized Trial

AbstractArsenic trioxide (ATO) is synergistic with ascorbic acid (AA) and melphalan against myeloma both in vitro and in vivo. The aim of this randomized phase II trial was to determine the safety and efficacy of a combination of ATO, melphalan, and AA as preparative regimen in 48 patients undergoing autologous hematopoietic stem cell transplantation (ASCT) for multiple myeloma (MM). Forty-eight patients received melphalan 200 mg/m2 i.v. over 2 days and AA 1000 mg i.v. over 7 days in 3 treatment arms: no ATO (arm 1), ATO 0.15 mg/kg i.v. × 7 days (arm 2), and ATO 0.25 mg/kg i.v. × 7 days (arm 3). No dose-limiting toxicity, engraftment failure, or nonrelapse mortality (NRM) was seen in the first 100 days post-ASCT. Complete responses (CR) were seen in 12 of 48 patients (25%), with an overall response rate (ORR = CR + PR) of 85%. Median progression-free survival (PFS) was 25 months; median overall survival (OS) has not yet been reached. There was no significant difference in CR, PFS, or OS among the 3 treatment arms, and no adverse effect of ATO on melphalan pharmacokinetics. Addition of ATO + AA to high-dose melphalan is safe and well tolerated as a preparative regimen for MM

Measuring Global Multi-Scale Place Connectivity Using Geotagged Social Media Data

Shaped by human movement, place connectivity is quantified by the strength of spatial interactions among locations. For decades, spatial scientists have researched place connectivity, applications, and metrics. The growing popularity of social media provides a new data stream where spatial social interaction measures are largely devoid of privacy issues, easily assessable, and harmonized. In this study, we introduced a global multi-scale place connectivity index (PCI) based on spatial interactions among places revealed by geotagged tweets as a spatiotemporal-continuous and easy-to-implement measurement. The multi-scale PCI, demonstrated at the US county level, exhibits a strong positive association with SafeGraph population movement records (10% penetration in the US population) and Facebook\u27s social connectedness index (SCI), a popular connectivity index based on social networks. We found that PCI has a strong boundary effect and that it generally follows the distance decay, although this force is weaker in more urbanized counties with a denser population. Our investigation further suggests that PCI has great potential in addressing real-world problems that require place connectivity knowledge, exemplified with two applications: (1) modeling the spatial spread of COVID-19 during the early stage of the pandemic and (2) modeling hurricane evacuation destination choice. The methodological and contextual knowledge of PCI, together with the open-sourced PCI datasets at various geographic levels, are expected to support research fields requiring knowledge in human spatial interactions