Magnetization of ferrofluids with dipolar interactions - a Born--Mayer expansion

For ferrofluids that are described by a system of hard spheres interacting via dipolar forces we evaluate the magnetization as a function of the internal magnetic field with a Born--Mayer technique and an expansion in the dipolar coupling strength. Two different approximations are presented for the magnetization considering different contributions to a series expansion in terms of the volume fraction of the particles and the dipolar coupling strength.Comment: 19 pages, 11 figures submitted to PR

Desempenho silvicultural de híbridos de Eucalyptus em função do preparo de solo, na Chapada do Araripe, PE.

Resumo

Development of Coleomegilla maculata De Geer (Coleoptera: coccinellidae) with prey and artificial diet.

Coleomegilla maculata De Geer (Coleoptera: Coccinellidae) is an important predator and has the potential to be used as a biological control agent of insect pests of maize (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench]. This study aimed to evaluate the development of C. maculata larvae fed eggs Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) alone or associated with artificial diet, eggs of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) and nymphs of Schizaphis graminum (Rondani) (Hemiptera: Aphididae). The experiment was conducted in a complete randomized design with four replications, each with 10 larvae of C. maculata in an acclimatized room (25 ± 1 ºC, 70 ± 10% RH and 12 hours photophase). The duration of the stages of C. maculata was similar in all treatments, except for one that used nymphs of S. graminum, resulting in a shorter period for the larval stage. The viability of larval, prepupal and pupal stages and larval to adult C. maculata was high and similar in all treatments. No effect of diets on the weight of C. maculata adults occurred, except for the heavier insects fed on eggs of A. kuehniella, whose males and females weighed 9.8 ± 0.3 mg and 13.3 ± 0.5 mg, respectively

Integrated platform resorting to ionic liquids comprising the extraction, purification and preservation of DNA

The large-scale production of therapeutically targeted-deoxyribonucleic acid (DNA) has passed through several challenges, postponing the tangible implementation of an effective, economic and sustainable manufacturing system. Such challenges comprise the need to develop an integrative downstream process able to extract, purify and long-term preserve DNA, whilst reducing the risk of degradation by endonucleases that would compromise their effectiveness as therapeutic products. In this work, three-phase partitioning (TPP) systems formed by the application of aqueous biphasic systems (ABS) composed of several biocompatible cholinium-based ionic liquids (ILs), are proposed for the separation of double stranded DNA (dsDNA) from the endonuclease deoxyribonuclease I (DNase I). By taking advantage of the tailor-made properties of ILs, dsDNA can be completely extracted to the IL-rich phase, whereas DNase I is precipitated at the ABS interphase. The ABS/TPP formed by IL cholinium glycolate ([N 111(2OH) ][Gly]) fulfills the aim of this work, i.e. at ensuring the technical viability of IL-based ABS/ TPP for the “one-pot” extraction, purification and long-term preservation of dsDNA. The results reveal the potential of this system to be applied in the bioprocessing of DNA, particularly relevant when envisioning DNA- based therapeutic products.publishe

Validity of self-reported weight: a study of urban brazilian adults

Para avaliar a validade do peso auto-referido em inquéritos de prevalência de obesidade, o mesmo foi comparado com o peso medido de 659 adultos, residentes em Porto Alegre, RS, Brasil, em 1986-87. Ambos os pesos foram obtidos por entrevistador, na casa do participante, na mesma ocasião. A média das diferenças entre peso auto-referido e peso medido foi pequena (-0,06 +/-3,16 kg; média +/- desvio padrão) e a correlação entre eles alta (r=0,97). Sessenta e dois por cento dos participantes referiram seu peso com erro < 2 kg, 87% com erro menor do que 4 kg e 95% com erro < 6 kg. Indivíduos de baixo peso hiperestimaram seu peso, o oposto ocorrendo com indivíduos obesos (p; 30) por peso referido, foi de 10% e a por peso medido, de 11%. Concluindo, a validade do peso auto-referido é aceitável para inquéritos de prevalência realizados em contextos similares.In order to evaluate the validity of self-reported weight for use in obesity prevalence surveys, self-reported weight was compared to measured weight for 659 adults living in the Porto Alegre county, RS Brazil in 1986-87, both weights being obtained by a technician in the individual's home on the same visit. The mean difference between self-reported and measured weight was small (-0.06 +/- 3.16 kg; mean +/- standard deviation), and the correlation between reported and measured weight was high (r=0.97). Sixty-two percent of participants reported their weight with an error of < 2 kg, 87% with an error of < 4 kg, and 95% with an error of < 6 kg. Underweight individuals overestimated their weight, while obese individuals underestimated theirs (p; 30) by reported weight was 10%, by measured weight 11%. Thus, the validity of reported weight is acceptable for surveys of the prevalence of ponderosity in similar settings