Classical limit for the scattering of Dirac particles in a magnetic field

We present a relativistic quantum calculation at first order in perturbation theory of the differential cross section for a Dirac particle scattered by a solenoidal magnetic field. The resulting cross section is symmetric in the scattering angle as those obtained by Aharonov and Bohm (AB) in the string limit and by Landau and Lifshitz (LL) for the non relativistic case. We show that taking pr_0\|sin(\theta/2)|/\hbar<<1 in our expression of the differential cross section it reduces to the one reported by AB, and if additionally we assume \theta << 1 our result becomes the one obtained by LL. However, these limits are explicitly singular in \hbar as opposed to our initial result. We analyze the singular behavior in \hbar and show that the perturbative Planck's limit (\hbar -> 0) is consistent, contrarily to those of the AB and LL expressions. We also discuss the scattering in a uniform and constant magnetic field, which resembles some features of QCD

Human cerebral organoids and fetal brain tissue share proteomic similarities

The limited access to functional human brain tissue has led to the development of stem cell-based alternative models. The differentiation of human pluripotent stem cells into cerebral organoids with self-organized architecture has created novel opportunities to study the early stages of the human cerebral formation. Here we applied state-of-the-art label-free shotgun proteomics to compare the proteome of stem cell-derived cerebral organoids to the human fetal brain. We identified 3,073 proteins associated with different developmental stages, from neural progenitors to neurons, astrocytes, or oligodendrocytes. The major protein groups are associated with neurogenesis, axon guidance, synaptogenesis, and cortical brain development. Glial cell proteins related to cell growth and maintenance, energy metabolism, cell communication, and signaling were also described. Our data support the variety of cells and neural network functional pathways observed within cell-derived cerebral organoids, confirming their usefulness as an alternative model. The characterization of brain organoid proteome is key to explore, in a dish, atypical and disrupted processes during brain development or neurodevelopmental, neurodegenerative, and neuropsychiatric diseases7CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPNão temNão temNão temNão tem14/21035-0; 16/07332-7; 13/08711-3; 14/10068-4JN, VS-C, and DM-D-S are supported by the São Paulo Research Foundation (FAPESP) grants 14/21035-0, 16/07332-7, 13/08711-3, and 14/10068-4. CS was recipient of a CAPES-FAPERJ Postdoc fellowship. Other funds are provided by the National Council for Scientific and Technological Development (CNPq), the Instituto Nacional de Ciência e Tecnologia de Neurociência Translacional (INCT-INNT), Foundation for Research Support in the State of Rio de Janeiro (FAPERJ), Coordination for the Improvement of Higher Education Personnel (CAPES), Brazilian Funding Authority for Studies and Projects (FINEP), and Brazilian Development Bank (BNDES

A Systematic Review of Digital vs Analog Drainage for Air Leak After Surgical Resection or Spontaneous Pneumothorax

Background The concerns regarding air leak after lung surgery or spontaneous pneumothorax include detection and duration. Prior studies have suggested that digital drainage systems permit shorter chest tube duration and hospital length of stay (LOS) by earlier detection of air leak cessation. We conducted a systematic review to assess the impact of digital drainage on chest tube duration and hospital LOS after pulmonary surgery and spontaneous pneumothorax. Methods Ovid MEDLINE, PubMed, Embase, the Cochrane Library, Scopus, and Google Scholar were searched from inception through January 2019. We included randomized controlled trials, cohort studies, and case series of adult patients, using digital or traditional drainage devices for air leaks of either postsurgical or spontaneous pneumothorax origin. Results Of 1,272 references reviewed, 23 articles were included. Nineteen articles addressed postoperative air leak, and four articles pertained to air leak after spontaneous pneumothorax. Thirteen studies were randomized controlled trials. Digital drainage resulted in significantly shorter chest tube duration in eight of 18 studies and shorter hospital LOS in six of 14 studies for postoperative air leak. For postpneumothorax air leak, digital drainage resulted in significantly shorter chest tube duration in two of three studies and hospital LOS in one of two studies with an analog control group. Conclusions Most studies show no significant differences in chest tube duration and hospital LOS with digital vs analog drainage systems for patients with air leak after pulmonary resection. For post-spontaneous pneumothorax air leak, the limited published evidence suggests shorter chest tube duration and hospital LOS with digital drainage systems

Mejora del m?todo de deducci?n de intereses en el financiamiento entre empresas y su efecto fiscal en el Per?

Con la promulgaci?n del Decreto Legislativo N? 1424 se prev?, a partir del a?o 2012, la aplicaci?n de una norma anti elusiva cuyo objeto es limitar la deducci?n de intereses generados por pr?stamos suscritos entre empresas. Dicha norma ha sido analizada, pudi?ndose apreciar como resultado de dicho an?lisis que la misma presenta debilidades en su estructura, lo cual generar?a un impacto considerable, ocasionando perjuicios econ?micos a las empresas. En estas circunstancias, se propone una mejora a la norma anti elusiva, la cual se sustenta en la legislaci?n comparada, los an?lisis de informaci?n financiera de las principales empresas nacionales, las entrevistas realizadas a especialistas y las diversas publicaciones especializadas de reconocidos juristas tributarios

Drama and discounting in the relational dynamics of corporate social responsibility

Employing theoretical resources from Transactional Analysis (TA) and drawing from interviews with managers dealing with social or environmental issues in their role, we explain how CSR activity provides a context for dramas in which actors may ignore, or discount aspects of self, others, and the contexts of their work as they maintain and reproduce the roles of Rescuers, Persecutors and Victims. In doing so, we add to knowledge about CSR by providing an explanation for how the contradictions of CSR are avoided in practice even when actors may be aware of them. Specifically, we theorise how CSR work can produce dramatic stories where adversity is apparently overcome, whilst little is actually achieved at the social level. We also add to the range of psychoanalytic tools used to account for organisational behaviours, emphasising how TA can explain the relational dynamics of CSR