Superconducting thin rings with finite penetration depth

Recently Babaei Brojeny and Clem [Phys. Rev. B 68, 174514 (2003)] considered superconducting thin-film rings in perpendicular magnetic fields in the ideal Meissner state with negligibly small magnetic penetration depth and presented useful analytical limiting expressions and numerical results for the magnetic-field and sheet-current profiles, trapped magnetic flux, self-inductance, magnetic moment, and focusing of magnetic flux into the hole when no net current flows in the ring. The present paper generalizes all these results to rings with arbitrary values of the two-dimensional effective penetration depth \Lambda = \lambda^2 /d (\lambda is the London depth and d < \lambda/2 the film thickness) using a straightforward matrix inversion method. We also present results for the energy of a superconducting ring as a function of the applied magnetic induction B_a and the quantum number N defining the size of the fluxoid N \phi_0 trapped in the hole.Comment: with 19 figures, gives 11.5 page

Two-photon final states in peripheral heavy ion collisions

We discuss processes leading to two photon final states in peripheral heavy ion collisions at RHIC. Due to the large photon luminosity we show that the continuum subprocess $\gamma \gamma \to \gamma \gamma$ can be observed with a large number of events. We study this reaction when it is intermediated by a resonance made of quarks or gluons and discuss its interplay with the continuum process, verifying that in several cases the resonant process ovewhelms the continuum one. It is also investigated the possibility of observing a scalar resonance (the $\sigma$ meson) in this process. Assuming for the $\sigma$ the mass and total decay width values recently reported by the E791 Collaboration we show that RHIC may detect this particle in its two photon decay mode if its partial photonic decay width is of the order of the ones discussed in the literature.Comment: 10 pages, 8 figure

Agricultura familiar, multifuncionalidade da agricultura e ruralidade: interfaces de uma realidade complexa.

Nas últimas décadas, assistimos à revitalização do debate em torno da agricultura familiar pela incorporação das discussões sobre as múltiplas funções da agricultura num rural que não pode mais ser visto como domínio exclusivo da atividade agrícola e dos agricultores. No contexto brasileiro, acreditamos que essa discussão deva ser permeada pela análise de como processos diferenciados de distribuição fundiária e desenvolvimento econômico e o tipo de agricultura resultante geram ruralidades específicas com características como, no caso da agricultura familiar, a manutenção de práticas sociais e de trabalho marcadas pelas relações de parentesco e vizinhança presentes numa sociedade de interconhecimento. Partindo desse princípio, este trabalho analisa a agricultura familiar de um bairro rural do município de Ouro Fino - MG, sua herança histórica e sua participação na criação de uma paisagem natural e humana que muito contribui para a atratividade da região

As múltiplas funções da agricultura familiar: um estudo no assentamento Monte Alegre, região de Araraquara (SP).

A partir da emergência da ideia de sustentabilidade, a agricultura adquiriu novas conotações, associadas não apenas ao aspecto produtivo, mas também à conservação dos recursos naturais e dos territórios rurais, em um reconhecimento de sua multifuncionalidade. Com base nesta noção, que valoriza as funções socioambientais desempenhadas pelas famílias rurais e pelas agriculturas praticadas, o presente artigo analisa um assentamento rural no estado de São Paulo, buscando identificar quais são e de que forma se expressam as funções para além da produção neste território particular. Por meio de uma metodologia de cunho quali-quantitativo, observou-se que, no assentamento em foco, a agricultura encerra em si questões de coesão territorial, manutenção da segurança alimentar, conservação da agrobiodiversidade e de fomento a outras atividades produtivas, sendo o elemento central da reconstrução de um modo de vida rural neste ambiente

Guided vortex motion in superconductors with a square antidot lattice

We have measured the in-plane anisotropy of the vortex mobility in a thin Pb film with a square array of antidots. The Lorentz force, acting on the vortices, was rotated by adding two perpendicular currents and keeping the amplitude of the net current constant. One set of voltage probes was used to detect the vortex motion. We show that the pinning landscape provided by the square antidot lattice influences the vortex motion in two different ways. First, the modulus of the vortex velocity becomes angular dependent with a lower mobility along the diagonals of the pinning array. Second, the vortex displacement is preferentially parallel to the principal axes of the underlying pinning lattice, giving rise to a misalignment between the vortex velocity and the applied Lorentz force. We show that this anisotropic vortex motion is temperature dependent and progressively fades out when approaching the normal state.Comment: 5 pages, 4 figure

Integrative overview of the herpetofauna from serra da mocidade, a granitic mountain range in northern Brazil

The Brazilian mountain ranges from the Guiana Shield highlands are largely unexplored, with an understudied herpetofauna. Here the amphibian and reptile species diversity of the remote Serra da Mocidade mountain range, located in extreme northern Brazil, is reported upon, and biogeographical affinities and taxonomic highlights are discussed. A 22-days expedition to this mountain range was undertaken during which specimens were sampled at four distinct altitudinal levels (600, 960, 1,060 and 1,365 m above sea level) using six complementary methods. Specimens were identified through an integrated approach that considered morphological, bioacoustical, and molecular analyses. Fifty-one species (23 amphibians and 28 reptiles) were found, a comparable richness to other mountain ranges in the region. The recorded assemblage showed a mixed compositional influence from assemblages typical of other mountain ranges and lowland forest habitats in the region. Most of the taxa occupying the Serra da Mocidade mountain range are typical of the Guiana Shield or widely distributed in the Amazon. Extensions of known distribution ranges and candidate undescribed taxa are also recorded. This is the first herpetofaunal expedition that accessed the higher altitudinal levels of this mountain range, contributing to the basic knowledge of these groups in remote areas. © Leandro J.C.L. Moraes et al

Records of Mantodea (Insecta) collected with light trap at 45 meters height over an Amazon forest canopy, at ZF-2 nucleus, Manaus, Brazil

Insect collections were carried out monthly from January to December of 2004, during three nights of lunar transition third quarter moon/new moon from 18 p.m. to 6 a.m. They were collected over a vertical white sheet illuminated by a 250 watts mixed light and a 20 watts black light (BL) and black light bulb (BLB) lamps. The light trap was mounted at 45 meters height in a metallic tower of 50 meters height, in a "platô de terra firme", in the Cueiras River basin, in Manaus, Amazonas, Brazil. It was collected 23 species of Mantodea: Chaeteessidae (1 species); Mantoididae (2); Mantidae (15); Thespidae (2) and Acanthopidae (3). Six new species were registered and they will be described opportunely in the following genera: Cardioptera Burmeister, 1838; Phyllovates Kirby, 1904; Pseudovates Saussure, 1869; Stagmomantis Saussure, 1869; Stagmatoptera Burmeister, 1838 and Metilia Stal, 1877. Three species previously recorded to an indetermined Brazilian region are being recorded to Brazilian Amazon: Heterovates pardalina Saussure, 1872; Macromantis ovalifolia (Stoll, 1813) and Photina reticulata (Burmeister, 1838). Four records are new for the Amazonas state: Angela guianensis Rehn, 1906; Photina gracillis Giglio-Tos, 1915; Raptrix perspicua (Fabricius, 1787) and Vates festae Gigio-Tos, 1914. The specimens number collected monthly are presented for each species.Foram realizadas coletas mensais de insetos de janeiro a dezembro de 2004, durante três noites de transição lunar minguante/nova, das 18:00 às 06:00 horas. Os espécimes foram capturados em um lençol iluminado com lâmpada de 250 watts, luz mista de vapor de mercúrio e lâmpada de 20 watts black light (BL) e black light bulb (BLB). A armadilha foi montada a 45 metros de altura numa torre metálica de 50 metros, que ultrapassa a maioria das copas das árvores, num platô de terra firme, na bacia do rio Cuieiras, Manaus, Amazonas, Brasil. Foram coletados 23 espécies de Mantodea, sendo Chaeteessidae (1 espécie); Mantoididae (2); Mantidae (15); Thespidae (2) e Acanthopidae (3). Seis espécies são novas e serão descritas oportunamente nos seguintes gênerosCardioptera Burmeister, 1838, Phyllovates Kirby, 1904, Pseudovates Saussure, 1869, Stagmomantis Saussure, 1869, Stagmatoptera Burmeister, 1838 e Metilia Stal, 1877. Três espécies registradas para o Brasil sem uma região determinada estão sendo registradas para a Amazônia brasileiraHeterovates pardalina Saussure, 1872, Macromantis ovalifolia (Stoll, 1813) e Photina reticulata (Burmeister, 1838). Quatro registros são novos para o estado do AmazonasAngela guianensis Rehn, 1906, Photina gracillis Giglio-Tos, 1915, Raptrix perspicua (Fabricius, 1787) e Vates festae Gigio-Tos, 1914. Os números de indivíduos, em cada coleta mensal, são apresentados para cada espécie

Emotional, hyperactivity and inattention problems in adolescents with immunocompromising chronic diseases during the COVID-19 pandemic

Objective: To assess factors associated with emotional changes and Hyperactivity/Inattention (HI) motivated by COVID-19 quarantine in adolescents with immunocompromising diseases. Methods: A cross-sectional study included&nbsp;343&nbsp;adolescents with immunocompromising diseases and 108&nbsp;healthy adolescents. Online questionnaires were answered including socio-demographic data and self-rated healthcare routine during COVID-19 quarantine and validated surveys: Strengths and Difficulties Questionnaire (SDQ), Pittsburgh Sleep Quality Index (PSQI), Pediatric Quality of Life Inventory 4.0 (PedsQL4.0). Results: The frequencies of abnormal emotional SDQ scores from adolescents with chronic diseases were similar to those of healthy subjects (110/343&nbsp;[32%] vs.&nbsp;38/108 [35%], p&nbsp;=&nbsp;0.548), as well as abnormal hyperactivity/inattention SDQ scores (79/343 [23%] vs.&nbsp;29/108 [27%], p&nbsp;=&nbsp;0.417). Logistic regression analysis of independent variables associated with abnormal emotional scores from adolescents with chronic diseases showed: female sex (Odds Ratio [OR&nbsp;=&nbsp;3.76]; 95%&nbsp;Confidence Interval (95%&nbsp;CI) 2.00‒7.05; p &lt; 0.001), poor sleep quality (OR&nbsp;=&nbsp;2.05; 95%&nbsp;CI&nbsp;1.08‒3.88; p&nbsp;=&nbsp;0.028) and intrafamilial violence during pandemic (OR&nbsp;=&nbsp;2.17; 95%&nbsp;CI&nbsp;1.12‒4.19; p&nbsp;=&nbsp;0.021) as independently associated with abnormal emotional scores, whereas total PedsQL score was inversely associated with abnormal emotional scores (OR&nbsp;=&nbsp;0.95; 95%&nbsp;CI&nbsp;0.93‒0.96; p &lt; 0.0001). Logistic regression analysis associated with abnormal HI scores from patients evidenced that total PedsQL score (OR&nbsp;=&nbsp;0.97; 95%&nbsp;CI&nbsp;0.95‒0.99; p&nbsp;=&nbsp;0.010], changes in medical appointments during the pandemic (OR&nbsp;=&nbsp;0.39; 95%&nbsp;CI&nbsp;0.19-0.79; p&nbsp;=&nbsp;0.021), and reliable COVID-19 information (OR&nbsp;=&nbsp;0.35; 95%&nbsp;CI&nbsp;0.16‒0.77; p&nbsp;=&nbsp;0.026) remained inversely associated with abnormal HI scores. Conclusion: The present study showed emotional and HI disturbances in adolescents with chronic immunosuppressive diseases during the COVID-19 pandemic. It reinforces the need to promptly implement a longitudinal program to protect the mental health of adolescents with and without chronic illnesses during future pandemics