Schr\"odinger formalism for a particle constrained to a surface in R13\mathbb{R}_1^3

In this work it is studied the Schr\"odinger equation for a non-relativistic particle restricted to move on a surface $S$ in a three-dimensional Minkowskian medium $\mathbb{R}_1^3$, i.e., the space $\mathbb{R}^3$ equipped with the metric $\text{diag}(-1,1,1)$. After establishing the consistency of the interpretative postulates for the new Schr\"odinger equation, namely the conservation of probability and the hermiticity of the new Hamiltonian built out of the Laplacian in $\mathbb{R}_1^3$, we investigate the confining potential formalism in the new effective geometry. Like in the well-known Euclidean case, it is found a geometry-induced potential acting on the dynamics $V_S = - \frac{\hbar^{2}}{2m} \left(\varepsilon H^2-K\right)$ which, besides the usual dependence on the mean ($H$) and Gaussian ($K$) curvatures of the surface, has the remarkable feature of a dependence on the signature of the induced metric of the surface: $\varepsilon= +1$ if the signature is $(-,+)$, and $\varepsilon=1$ if the signature is $(+,+)$. Applications to surfaces of revolution in $\mathbb{R}^3_1$ are examined, and we provide examples where the Schr\"odinger equation is exactly solvable. It is hoped that our formalism will prove useful in the modeling of novel materials such as hyperbolic metamaterials, which are characterized by a hyperbolic dispersion relation, in contrast to the usual spherical (elliptic) dispersion typically found in conventional materials.Comment: 26 pages, 1 figure; comments are welcom

Four gene introduction methods affect the shoot regeneration and localization of transgene expression in greenhouse stem explants and in vitro-grown chrysanthemum stem thin cell layers

Gene introduction method (GIM) affected shoot regeneration capacity (SRC) in standard and spray-type chrysanthemums. SRC was both cultivar and GIM-dependent in both in vitro and greenhouse stem explants, the former significantly higher than the latter. Sonication had an SRC-stimulating effect on in vitro explants. Other GIMs (Agrobacterium, biolistics, Agrolistics) had an SRC-inhibiting effect on greenhouse explants. Genotype-dependence of SRC was observed in both in vitro and greenhouse material. SRC is influenced by the explant and regeneration media, which should be modified if altered by the GIM. Shoots derived from all GIM treatments showed normal growth under in vitro and greenhouse conditions, and flowered normally. In addition, this study further shows that explant origin (in vitro versus greenhouse) and cultivar significantly affect the regeneration process, even when an optimized medium is utilized. The integration of the GUS transgene is also GIM-dependent, but in all cases is shown to occur in the venation. (African Journal of Biotechnology: 2003 2(5): 114-123

Individual actors and embeddedness in business-to-business interactions

Individual actors are hardly ever considered in business-to-business marketing literature. This paper uses Service-dominant Logic and Neo-institutional Theory as the bases for twelve case studies. These case studies provide a better understanding of how individuals who represent firms make sense of the social rules, norms, procedures, values, and beliefs of the network (i.e. institutional logics) where they are embedded and how the business interaction is shaped by those influences, through the individual behaviour. This paper makes two main contributions. First, we develop an empirical model of how individuals consider the institutional logics of the network in interactions with suppliers. Second, we present three patterns of individual behavior in interactions, different from what is often assumed by business-to-business researchers. Managerial contributions are also pointed out.info:eu-repo/semantics/acceptedVersio

Enraizamento in vitro das especies P. hispidinervum e P. aduncum utilizando diferentes concentrações de AIA.

A pimenta longa (Piper hispidinervum) e a pimenta de macaco (Piper aduncum) são espécies pertencentes à família botânica das Piperaceas e encontram-se entre as plantas aromáticas que fornecem óleo essencial rico nos respectivos compostos secundários, safrol e dilapiol, substâncias amplamente utilizadas em diversos setores industriais. O objetivo deste trabalho foi avaliar o efeito de diferentes concentrações do ácido indolilacético-AIA (0,0; 0,25; 0,5; 0,75; 1,0 e 2,0 mg.L-1) no enraizamento in vitro destas espécies. Brotos oriundos de plântulas germinadas in vitro foram inoculados em meio semi-sólido MS pleno com 3% de sacarose e suplementado com diversas concentrações do AIA. As culturas foram mantidas em sala de crescimento à temperatura controlada de 25+2ºC, expostas ao fotoperíodo de 16 horas de luz com intensidade luminosa de 30 umol.m2.s-1. Após 50 dias de incubação foram avaliadas as seguintes variáveis: porcentagem de enraizamento, comprimento da raiz principal, comprimento da parte aérea, número de folhas e número de raízes. O delineamento experimental utilizado foi inteiramente casualizado, com 6 repetições por tratamento e 4 explantes por repetição. Obteve-se 100% de enraizamento em todos os tratamentos utilizados para as duas espécies. As raízes surgidas apresentavam-se esbranquiçadas e com ramificações, indicando a formação de um sistema radicular eficiente, fato que sugere que esta planta não necessita da adição de auxina exógena

Radiação solar global e insolação no município de Juazeiro-BA.

O objetivo desse trabalho foi determinar os coeficientes da equação de Angström para cada mês no município de Juazeiro-BA

Letter to the editor: Should stricter regulations be set for the use or analysis of Twitter (and other social media) in academic publishing?

Currently, the pursuit of research utilizing Twitter data, alongside various other social media platforms, has become an increasingly prevalent undertaking (Sinnenberg et al., 2017). The recent (end of June 2023) restrictions placed by Twitter (now X) on public access to Tweets, requiring a login in order to view them, compounded by a daily limit to the number of Tweets that can be viewed, places – we feel – a damper on open communication via social media and is thus counter to open science principles. These communication and linking limitations seem to, in one respect, defeat the purpose of such social media platforms, which should be open to the public, at least to view such communications. With truncated access, the freedom and spirited nature of communication become limited

Assessment of retracted papers, and their retraction notices, from a cancer journal associated with “paper mills”

Cancer research is occasionally described as being in a reproducibility crisis. The cancer literature has ample papers retracted due to misconduct, including the use of paper mills, invalid authorship, or fake data. The objective of this paper was to gain an appreciation of the balance of retractions and associated retraction notices of 23 retracted Cancer Biotherapy and Radiopharmaceuticals papers associated with paper mills. By 23 March 2023, these retracted papers had already accumulated 287 citations according to Web of Science Core Collection, 253 according to Scopus, and 365 according to Google Scholar, i.e., metrically speaking, they were highly rewarded. All authors had an affiliation (71% being a hospital) in China. Most (12/21; 57%) of corresponding authors had emails with a @163.com suffix. Four of the retraction notices (i.e., 17%) explicitly indicated paper mills as a reason for retraction although, in general, the retraction notices lacked details and background that could assist readers’ understanding of the retractions

Most Preprint Servers Allow the Publication of Opinion Papers

Preprints are not only a raw form of research presentation, but also increasingly used as a gateway of entry into peer-reviewed journals. Several preprint servers are in existence, and some serve specific thematic groups or specialties, while others have a broader thematic scope. In this letter, we examined 36 preprint servers in March of 2023, noting that the majority (27/36 or 75%) accept opinion papers, two have an unclear, unstated, or unknown set of policies, while seven, including some of the most popular (biorXiv, medRxiv, Research Square), do not explicitly accommodate opinion papers. We opine that it would be in the interests of those preprint servers that do not publish opinion papers or evidence-based opinion papers to modify their scope of manuscript types in order to expand their user base and attract more participating scientists, but also to provide a more holistic set of scientific publishing objectives that accommodates a wider and more inclusive range of views