Refractive index of a transparent liquid measured with a concave mirror

This paper describes the spherical concave mirror method for measuring the index of refraction of transparent liquids. We derived the refractive index equation using Snell's law and the small-angle approximation. We also verified the validity of this method using the traditional spherical mirror and thin-lens Gaussian equations.Comment: IOPart, 8 pages, 4 figure

Radiographic findings in hereditary multiple exostoses and a new theory of the pathogenesis of exostoses.

Analysis of 330 exostoses in 18 patients affected by hereditary multiple exostoses disease suggested a new classification of exostoses as eccentric or full-thickness. Radiographically arrest of metaphyseal remodeling with failure of coning and persistence of the primary metaphyseal trabeculae was evident in full-thickness exostoses. Similar bone lesions can be obtained experimentally with inhibitors of bone turn-over. A localized, peripheral defect in remodeling over a limited time can give a satisfactory explanation also for the origin of eccentric exostoses. The thesis that this is the basic mechanism of exostosis formation is presented

A photonic basis for deriving nonlinear optical response

Nonlinear optics is generally first presented as an extension of conventional optics. Typically the subject is introduced with reference to a classical oscillatory electric polarization, accommodating correction terms that become significant at high intensities. The material parameters that quantify the extent of the nonlinear response are cast as coefficients in a power series - nonlinear optical susceptibilities signifying a propensity to generate optical harmonics, for example. Taking the subject to a deeper level requires a more detailed knowledge of the structure and properties of each nonlinear susceptibility tensor, the latter differing in form according to the process under investigation. Typically, the derivations involve intricate development based on time-dependent perturbation theory, assisted by recourse to a set of Feynman diagrams. This paper presents a more direct route to the required results, based on photonic rather than semiclassical principles, and offers a significantly clearer perspective on the photophysics underlying nonlinear optical response. The method, here illustrated by specific application to harmonic generation and down-conversion processes, is simple, intuitive and readily amenable for processes of arbitrary photonic order. © 2009 IOP Publishing Ltd

Conteúdo fenólico in vitro em açucena durante a organogênese.

Apesar de a produção de compostos fenólicos in vitro ser associada à inibição da morfogênese, em estudos preliminares foi observado que a formação destes compostos em explantes de segmentos de bulbos de Hippeastrum aulicum antecedeu o processo organogênico. Neste sentido, o objetivo deste trabalho foi identificar a composição de ácidos fenólicos presentes nos explantes de segmentos de bulbos de H. aulicum para verificar a relação destes compostos com as respostas observadas in vitro. Foram analisados qualitativamente e quantitativamente a composição de ácidos fenólicos em tecidos de explantes com sintomas visuais de oxidação e em amostras de tecidos de bulbo intacto, por meio de cromatografia líquida de alta eficiência. Foram identificados os ácidos gálico, cinâmico e trans-cinâmico nos explantes de segmentos de bulbos e nos tecidos do bulbo com coloração natural, sendo observadas diferenças na concentração destes compostos entre as duas amostras. A presença de ácido cafeico apenas na amostra de tecidos do bulbo com coloração natural. De acordo com a literatura, estes compostos estão relacionados com o metabolismo da auxina. Assim, acredita-se que os mesmos podem ter influenciado a morfogênese em explantes de H. aulcum

Efeito de ANA e BAP na propagação in vitro de açucena.

As açucenas ou Hippeastrum produzem poucos propágulos vegetativos durante o crescimento, sendo a micropropagação uma alternativa para produção de mudas uma vez que através da técnica é possível a obtenção de plantas em larga escala em curto espaço de tempo, a partir de um mínimo de material vegetal. Assim, o objetivo deste trabalho foi avaliar o efeito de ANA e de BAP na propagação in vitro de H. aulicum. Explantes de segmentos de bulbo foram inoculados em meio de cultura MS suplementado com 0,00; 0,20; ou 1,00 uM de ANA, combinados com 0,20; 1,00 ou 4,00 uM de BAP. Após 60 dias, as brotações formadas foram transferidas para MS suplementado com 1,00 uM ANA e 10,00; 15,00 ou 30,00 uM de BAP. O meio com 1,00 uM de ANA e 4,00 uM de BAP foi o mais adequado para indução de brotações foliares e de bulbos por explante, em termos de número e vigor das mudas produzidas. Na fase de multiplicação, não foram observadas diferenças nas respostas com as doses de BAP testadas

Analysis of 19 Minerals and Cortisol in Red Deer Hair in Two Different Areas of the Stelvio National Park: A Preliminary Study

The aim of the study was to perform an investigation on the concentration of 19 minerals and cortisol in red deer (Cervuselaphus) hair, a matrix that is easy to collect with non-invasive and painless sampling, able to represent an integrative values of long-term substance concentrations, and able to give useful information, also when performed on dead animals, given its extreme stability over time. In the study thirty-five animals were included, coming from two different sides of a valley in the Stelvio National Park, where official water analysis had pointed out elevated concentrations of As in one of the two orographic sides. Hair cortisol concentrations were measured using a RIA(Radio Immuno Assay), while minerals were detected using ICP-MS (Inductively Coupled Plasma- Mass Spectrometry). Results showed a negative relationship between cortisol and some mineral concentrations (Li, Co, As, Cd, Cr and Tl) and significant differences in some mineral concentrations between park areas (Al, Co, Cu, Cd and Ni). As, Cr and cortisol differences approached statistical significance. This preliminary study represents a step forward in the study of wildlife allostatic load and a valid method for applications in wildlife management programs, in environmental studies and in public health programs

Aspectos da morfogênese in vitro de açucena.

O entendimento dos aspectos relacionados a diferenciação in vitro de brotações é importante, pois auxilia na otimização do desenvolvimento de protocolos de micropropagação. Neste trabalho foi estudado o início do processo morfogênico em explantes de camadas de bulbo de H. aulicum através de observações de cortes histológicos realizadas aos 10, 15, 60, 90 dias da inoculação em meio de cultura MS suplementado com 0,1 uM de ácido naftalenoacético e 4,0 uM de benzilaminopurina. Foi verificado que o início do processo morfogênico nos explantes de segmentos de bulbo de H. aulicum, ocorreu nas células epidérmicas e subepidérmicas da região abaxial das camadas, sendo que a provável função da porção do caule na qual elas estão inseridas seja o fornecimento de fitorreguladores

Differential contribution of the MTOR and MNK pathways to the regulation of mRNA translation in meiotic and postmeiotic mouse male germ cells

Translation of stored mRNAs accounts for protein synthesis during the transcriptionally inactive stages of spermatogenesis. A key step in mRNA translation is the assembly of the initiation complex EIF4F, which is regulated by the MTOR (mammalian target of rapamycin) and MNK1/2 (MAP kinase-interacting kinase 1 and 2) pathways. We investigated the expression and activity of regulatory proteins of these pathways in male germ cells at different stages of differentiation. All translation factors analyzed were expressed in germ cells throughout spermatogenesis. However, while EIF4G and PABP1 (poly[A]-binding protein 1) were more abundant in postmeiotic cells, MTOR and its target EIF4EBP1 (4E-BP1) decreased steadily during spermatogenesis. In vivo labeling showed that pachytene spermatocytes display higher rates of protein synthesis, which are partially dependent on MTOR and MNK activity. By contrast, haploid spermatids are characterized by lower levels of protein synthesis, which are independent of the activity of these pathways. Accordingly, MTOR and MNK activity enhanced formation of the EIF4F complex in pachytene spermatocytes but not in round spermatids. Moreover, external cues differentially modulated the activity of these pathways in meiotic and haploid cells. Heat shock decreased MTOR and MNK activity in pachytene spermatocytes, whereas round spermatids were much less sensitive. On the other hand, treatment with the phosphatase inhibitor okadaic acid activated MTOR and MNK in both cell types. These results indicate that translational regulation is differentially dependent on the MTOR and MNK pathways in mouse spermatocytes and spermatids and suggest that the late stages of germ cell differentiation display constitutive assembly of the translation initiation complex

Transversality of Electromagnetic Waves in the Calculus-Based Introductory Physics Course

Introductory calculus-based physics textbooks state that electromagnetic waves are transverse and list many of their properties, but most such textbooks do not bring forth arguments why this is so. Both physical and theoretical arguments are at a level appropriate for students of courses based on such books, and could be readily used by instructors of such courses. Here, we discuss two physical arguments (based on polarization experiments and on lack of monopole electromagnetic radiation), and the full argument for the transversality of (plane) electromagnetic waves based on the integral Maxwell equations. We also show, at a level appropriate for the introductory course, why the electric and magnetic fields in a wave are in phase and the relation of their magnitudes.Comment: 10 pages, 6 figure

Perception of nurses’ professional identity during the first wave of COVID-19 pandemic infections

Background and aim of the work: The main purpose of this study is to investigate on the experience of nurses working in the Covid-19 area focusing on their role’s perception. In particular, we explored the nurses’ perception of job satisfaction in relation to the images sent back by public opinion through the mass media and social communication channels. During the first wave of Covid-19 nurses have acquired media visibility, but their feeling is represented more by the discomfort of finding themselves suddenly glorified in the face of a lack of professional, social, and economic recognition. Materials and methods: A Mix-Method methodology and convenience sampling was adopted, on the population of professionals and students in post-graduate specializations, belonging to the Department of Medicine and Surgery of the University of Parma, and by nurses from the ASST-Bergamo Est, Lombardia Italy, who worked in the Covid emergency during the first wave of the pandemic, from February 2020 to May 2020. In the quantitative phase Stamm’s Professional Quality of Life Scale - ProQOL was administered to 89 respondents through a Google Form, In the qualitative phase, 3 Focus Groups were conducted on a total of 17 students. Results: At the ProQOL questionnaire, a moderate score was found in the Compassion Satisfaction scale (CF = 38.28) and in the Secondary Traumatic Stress subscale (STS-24.33), while low values emerged in the Burnout subscale (BO = 16.02). Five specific topics emerged from the focus groups: Professional collaboration, Job satisfaction, Nurse’s personal skills, Failure to protect the public image and the nursing profession. Conclusions: The professional collaboration, union with the work team, sense of solidarity, job satisfaction, professional growth, and awareness of one’s role seem to have worked favorably on Compassion Satisfaction, while keeping Compassion Fatigue levels under control