Snow metamorphism: a fractal approach

Snow is a porous disordered medium consisting of air and three water phases: ice, vapour and liquid. The ice phase consists of an assemblage of grains, ice matrix, initially arranged over a random load bearing skeleton. The quantitative relationship between density and morphological characteristics of different snow microstructures is still an open issue. In this work, a three-dimensional fractal description of density corresponding to different snow microstructure is put forward. First, snow density is simulated in terms of a generalized Menger sponge model. Then, a fully three-dimensional compact stochastic fractal model is adopted. The latter approach yields a quantitative map of the randomness of the snow texture, which is described as a three-dimensional fractional Brownian field with the Hurst exponent H varying as continuous parameter. The Hurst exponent is found to be strongly dependent on snow morphology and density. The approach might be applied to all those cases where the morphological evolution of snow cover or ice sheets should be conveniently described at a quantitative level

Keeping Pace with Information Literacy Instruction for the Real World: When Will MLS Programs Wake Up and Smell the LILACs?

For over thirty years, numerous studies have discussed the contradiction between the growing importance of information literacy instruction to the Library\u27s core mission and lack of pedagogical training for new librarians. This article reviews the more recent contributions on the topic, presents a survey of New York State MLS curricula and describes initiatives of pedagogy training offered in that region outside of MLS programs. The authors focus on the Library Instruction Leadership Academy (LILAC), an innovative, semester-long training program created in Western New York State to offer instruction in the pedagogical foundation and practical experience essential for teaching information literacy skills effectively. They provide details of the program\u27s content, organization, funding, assessment methods, and learning outcomes. While regional initiatives like LILAC prove to be very valuable to their participants, the authors aim to apply pressure on MLS programs to establish curricular requirements better suited to the demands of today\u27s librarianship

The Equal Rights Amendment: A Constitutional Basis for Equal Rights for Women

In the present legal structure, some laws exclude women from legalrights, opportunities, or responsibilities. Some are framed as legislationconferring special benefits, or protection, on women. Others create orperpetuate a separate legal status without indicating on their facewhether the position of women ranks below, or above, the positionof men. Many of the efforts to create a separate legal status for womenstem from a good faith attempt to advance the interests of women.Nevertheless, the preponderant effect has been to buttress the socialand economic subordination of women

A “leitura” do sentido das frações: manifestações de professores dos quintos e sextos anos em atividades desenvolvidas no grupo da segunda

O presente artigo tem por objetivo discutir o sentido de fração manifestado pelo coletivo de professores denominado Grupo da Segunda, em dois cenários suscitados na própria formação. O primeiro cenário se refere às questões de fração presentes na Prova Paraná de quintos e sextos anos e segundo a um roteiro investigativo utilizando o ábaco de frações. No que tange ao ensino das frações, verificou-se que o sentido atribuído pelo coletivo de professores e que contribui para a constituição de uma “vulgata” são as interpretações parte-todo, operador e quociente. Valendo-se de novas dinâmicas, todavia, os professores “experienciaram” a compreensão do papel da ação do sujeito na apropriação de uma nova noção de fração, da importância do ato de perguntar enquanto ingrediente que produz novas interpretações, sempre atentos à cultura escolar e ao processo de profissionalização docente compartilhado e constituído no âmbito de um coletivo de professores

Rescue of a genotype 4 human hepatitis E virus from cloned cDNA and characterization of intergenotypic chimeric viruses in cultured human liver cells and in pigs

Hepatitis E virus (HEV) is an important but extremely understudied human pathogen. Genotypes 1 and 2 are restricted to humans, whereas genotypes 3 and 4 are zoonotic, infecting both humans and pigs. This report describes, for the first time, the successful rescue of infectious HEV in vitro and in vivo from cloned cDNA of a genotype 4 human HEV (strain TW6196E). The complete genomic sequence of the TW6196E virus was determined and a full-length cDNA clone (pHEV-4TW) was assembled. Capped RNA transcripts from the pHEV-4TW clone were replication competent in Huh7 cells and infectious in HepG2/C3A cells. Pigs inoculated intrahepatically with capped RNA transcripts from pHEV-4TW developed an active infection, as evidenced by faecal virus shedding and seroconversion, indicating the successful rescue of infectious genotype 4 HEV and cross-species infection of pigs by a genotype 4 human HEV. To demonstrate the utility of the genotype 4 HEV infectious clone and to evaluate the potential viral determinant(s) for species tropism, four intergenotypic chimeric clones were constructed by swapping various genomic regions between genotypes 1 and 4, and genotypes 1 and 3. All four chimeric clones were replication competent in Huh7 cells, but only the two chimeras with sequences swapped between genotypes 1 and 4 human HEVs produced viruses capable of infecting HepG2/C3A cells. None of the four chimeras was able to establish a robust infection in pigs. The availability of a genotype 4 HEV infectious clone affords an opportunity to delineate the molecular mechanisms of HEV cross-species infection in the future

Sparse Positional Strategies for Safety Games

We consider the problem of obtaining sparse positional strategies for safety games. Such games are a commonly used model in many formal methods, as they make the interaction of a system with its environment explicit. Often, a winning strategy for one of the players is used as a certificate or as an artefact for further processing in the application. Small such certificates, i.e., strategies that can be written down very compactly, are typically preferred. For safety games, we only need to consider positional strategies. These map game positions of a player onto a move that is to be taken by the player whenever the play enters that position. For representing positional strategies compactly, a common goal is to minimize the number of positions for which a winning player's move needs to be defined such that the game is still won by the same player, without visiting a position with an undefined next move. We call winning strategies in which the next move is defined for few of the player's positions sparse. Unfortunately, even roughly approximating the density of the sparsest strategy for a safety game has been shown to be NP-hard. Thus, to obtain sparse strategies in practice, one either has to apply some heuristics, or use some exhaustive search technique, like ILP (integer linear programming) solving. In this paper, we perform a comparative study of currently available methods to obtain sparse winning strategies for the safety player in safety games. We consider techniques from common knowledge, such as using ILP or SAT (satisfiability) solving, and a novel technique based on iterative linear programming. The results of this paper tell us if current techniques are already scalable enough for practical use.Comment: In Proceedings SYNT 2012, arXiv:1207.055

Sobre a transição do 5º para o 6º ano do Ensino Fundamental : a gincana da integração como ação de intervenção

This paper proposes the Integration Gymkhana as an intervention action in the transition from the fifth to the sixth grade of elementary school, based on an experience lived by students, teachers, pre and in service, and researchers. It is a recreational activity designed and implemented within the scope of a research that investigated the transition in five public schools in West of Paraná, with support from CNPq. On the occasion, fifth grade students visited the schools where they could study in sixth grade and were welcomed by the pedagogical team and sixth grade students, who had just experienced this transition. The competitions were organized with emphasis on mathematics education as a way of promoting integration among participants. Experience points to the Integration Gymkhana as a fruitful action to promote interaction and assist in the reception of fifth grade students in the schools where they can study in the sixth grade.Este artigo propõe a Gincana da Integração como uma ação de intervenção na transição do quinto para o sexto ano do Ensino Fundamental, a partir de uma experiência vivida por estudantes, professores, em formação e em serviço, e pesquisadores. Trata-se de uma atividade recreativa pensada e implementada no âmbito de uma pesquisa que investigou a transição em cinco escolas públicas no Oeste do Paraná, com apoio do CNPq. Na ocasião, estudantes do quinto ano visitaram as escolas em que possivelmente estudariam no sexto ano e foram recepcionados pela equipe pedagógica e pelos estudantes do sexto ano, que recém vivenciaram essa transição. As provas foram organizadas prezando pela educação matemática como forma de promover a integração entre os participantes. A experiência aponta a Gincana da Integração como uma ação profícua para promover a interação e auxiliar na recepção dos estudantes do quinto ano nas escolas em que podem vir a estudar no sexto ano

A biophysical study of DNA condensation mediated by histones and protamines

The compaction of long DNA strands into confined spaces such as the nuclei of eukaryotic cells is an essential phenomenon towards the emergence of elaborated forms of life. Histones and protamines are the major nucleoproteins involved in this task participating in the formation of chromatin in somatic and germinative cells, respectively. In addition to a fundamental understanding of critical biological processes, DNA condensation also holds strong potential in biotechnology. Herein, we investigate the mesoscale structure of complexes formed between DNA and histones or protamines. A sophisticated set of biophysical methods encompassing steady-state fluorimetry, small-angle X-ray scattering and infrared nano spectroscopy was used to unveil both the self-assembly and molecular interactions of these complexes. We explored the fluorescence of a molecular rotor, thioflavin T, to investigate the accessibility of ligands in the inter-base environment of DNA strands. AFM-based infrared spectroscopy was used for the first time to probe the vibrational signature of individual DNA/nucleoprotein nano assemblies and disclose secondary-structure features. Our results show that protamines form highly compact structures in which DNA folding hinders access to the inter-base spacing. These assemblies exhibit diversified secondary-structure conformations, with the presence of -sheets stabilizing the packing. In contrast, histone-based complexes are characterized by fibrillar nano assemblies exhibiting larger inter strands separations and access to guest molecules that intercalate between bases. The findings presented here may help the understanding of DNA condensation mediated by these two major nucleoproteins and may assist the optimization of gene vehicles based on these promising nano assemblies.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP, 19/20907-

Anti-inflammatory response to acute exercise is related with intensity and physical fitness

Purpose: The relationship between inflammatory markers and energetic metabolism has been explored. However, the relation between exercise intensity and fitness-status is unclear and it is necessary to understand this relationship to apply specific exercise guidance. The purpose of the study was to analyze metabolic and inflammatory responses imposed by acute exercise sessions performed at moderate, heavy and severe intensities and their relationship with physical fitnessstatus. Methods: Nineteen healthy male volunteers performed three acute exercise sessions until exhaustion or up to 60 minutes on a cycle ergometer at moderate (90% of VT1), heavy (midpoint between VT1/VT2), and severe (midpoint between VT2/Wmax) intensities. Blood lactate, glucose, NEFA, endotoxin and cytokines were determined for each exercise session. Peripheral and LPS-stimulated release of TNF-α, IL-6 and IL-10 were analyzed pre, post and 60-min after sessions. Results: In peripheral blood, severe intensity increased lactate, endotoxin and TNF-α immediately post-exercise and glucose at 60-min post-exercise. There was a trend for IL-10 increase at 60-min post-exercise in peripheral blood. Immediately post-exercise, LPS-stimulated TNF-α, IL-6, IL-6/IL-10 ratio and lactate levels were higher in the severe intensity while NEFA levels decreased at this time. At 60-min post-exercise higher concentrations of glucose and a trend for increased IL-10 were observed in severe intensity. Positive correlation was observed between maximal aerobic power and IL-10 (r=0.513, p=0.042) and negative correlations between maximal aerobic power and endotoxin (r=-0.531, p=0.034) and lactate (r=-0.538, p=0.031) in heavy intensity. Conclusion: Our data show a novel finding that higher cytokine responses occur at higher intensities, mainly in severe intensity. However, the anti-inflammatory (IL-10) response was physical fitness-dependent

Structure optimization of lipopeptide assemblies for aldol reactions in an aqueous medium

Four amphiphilic peptides were synthesized, characterized, and evaluated regarding their efficiency in the catalysis of direct aldol reactions in water. The lipopeptides differ by having a double lipid chain and a guanidinium pyrrole group functionalizing one Lys side chain. All the samples are composed of the amino acids L-proline (P), L-arginine (R), or L-lysine (K) functionalized with the cationic guanidiniocarbonyl pyrrole unit (GCP), L-tryptophan (W), and L-glycine (G), covalently linked to one or two long aliphatic chains, leading to surfactant-like designs with controlled proline protonation state and different stereoselectivity. Critical aggregation concentrations (cac) were higher in the presence of the GCP group, suggesting that self-assembly depends on charge distribution along the peptide backbone. Cryogenic Transmission Electron Microscopy (Cryo-TEM) and Small Angle X-ray Scattering (SAXS) showed a rich polymorphism including spherical, cylindrical, and bilayer structures. Molecular dynamics simulations performed to assess the lipopeptide polymorphs revealed an excellent agreement with core-shell arrangements derived from SAXS data and provided an atomistic view of the changes incurred by modifying head groups and lipid chains. The resulting nanostructures behaved as excellent catalysts for aldol condensation reactions, in which superior conversions (>99%), high diastereoselectivities (ds = 94:6), and enantioselectivities (ee = 92%) were obtained. Our findings contribute to elucidate the effect of nanoscale organization of lipopeptide assemblies in the catalysis of aldol reactions in an aqueous environment.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)19/20907-