Orbital Magnetism in Ensembles of Parabolic Potentials

We study the magnetic susceptibility of an ensemble of non-interacting electrons confined by parabolic potentials and subjected to a perpendicular magnetic field at finite temperatures. We show that the behavior of the average susceptibility is qualitatively different from that of billiards. When averaged over the Fermi energy the susceptibility exhibits a large paramagnetic response only at certain special field values, corresponding to comensurate classical frequencies, being negligible elsewhere. We derive approximate analytical formulae for the susceptibility and compare the results with numerical calculations.Comment: 4 pages, 4 figures, REVTE

Geometrically induced singular behavior of entanglement

We show that the geometry of the set of quantum states plays a crucial role in the behavior of entanglement in different physical systems. More specifically it is shown that singular points at the border of the set of unentangled states appear as singularities in the dynamics of entanglement of smoothly varying quantum states. We illustrate this result by implementing a photonic parametric down conversion experiment. Moreover, this effect is connected to recently discovered singularities in condensed matter models.Comment: v2: 4 pags, 4 figs. A discussion before the proof of Proposition 1 and tomographic results were included, Propostion 2 was removed and the references were fixe

Otimização do processo não invasivo e não destrutivo de extração e análise de metabólitos voláteis de mamão papaia por SPME-GC-MS.

Abstract: The analysis of volatiles is an alternative in the routine of quality control of fruits, since the volatile metabolites can change in the presence of microorganisms. A well-established method for extracting volatiles is the solid phase microextraction (SPME). This work aims to define some parameters (fiber coating, conditioning time and fiber exposure time) for an effective extraction. Whole papaya was inserted into a hermetically closed glass bottle and the system was left in conditioning for the volatiles accumulation. Then, extraction by SPME and subsequent desorption in a gas chromatograph was performed. Two fibers were evaluated: a 100 &#956;m polydimethylsiloxane (PDMS) and a 65 &#956;m polydimethylsiloxane/divinylbenzene (PDMS/DVB). The PDMS/DVB fiber extracted the highest number of volatiles. Central composite design (CCD) was performed to assess the effect of papaya conditioning time and the fiber exposure time on the response: number of detectable peaks. Both variables studied and their interactions were significant for the response. ANOVA showed that the quadratic terms and the lack of fit were not significant (p <0.05). A conditioning time of 10 min and exposure time of 30 min was sufficient for the detection of more than 100 compounds

Sudden unexpected death in an adolescent with epilepsy: All roads lead to the heart?

The incidence of sudden unexpected death in epilepsy (SUDEP) has been estimated from 0.5-1.4/1,000 person-years in people with treated epilepsy, and 9/1,000 person-years in candidates for epilepsy surgery. Potential risk factors for SUDEP include: age, early onset of epilepsy, duration of epilepsy, uncontrolled seizures, seizure type and winter temperatures. The arrythmogenic side-effect of antiepileptic drugs and seizures may increase the risk of SUDEP. In this report, we describe a patient with prolonged post-ictal tachycardia in EEG video recordings with a typical case of SUDEP: a 16-year-old boy with medically intractable complex partial seizures. Magnetic resonance imaging revealed left mesial temporal sclerosis. During non-invasive video-EEG monitoring, the patient presented a post-ictal heart rate increased for five hours. Two months after video-EEG, he died from SUDEP during a tonic-clonic secondary generalized seizure. The possibility of cardiac involvement in the pathogenesis of SUDEP has been suggested by many studies. Evaluation of this patient with EEG-video monitoring, including measurement of heart rate, contributed to an identification of ictal tachycardia that may have played a role in the SUDEP. Premature mortality seems to be increased in patients with epilepsy, and cardiac abnormalities may be a possible cause of SUDEP. (Cardiol J 2011; 18, 2: 194-196

The filamentous fungi culture collection of the Department of Food Science (CCDCA), Federal University of Lavras, Brazil

Brazil has one of the highest levels of biological diversity due to its large geographical area, high coverage by rainforests, and endemic biomes, such as the Brazilian Atlantic Forest, Cerrado and Caatinga. Of the estimated 1.5 million species of fungi only 5% are known. Much of this unknown biodiversity is in the tropics, which is seriously threatened by some agricultural activities, reinforcing the urgent need for biodiversity studies in these areas. The maintenance and preservation of fungal cultures are important elements for such a requirment. The establishment of a culture collection of filamentous fungi in the Mycotoxins and Mycology Laboratory, Department of Food Science (CCDCA), Federal University of Lavras (UFLA) commenced from the bases of species maintenance, taxonomy, biotechnology and toxigenicity. The laboratory was established in 2007 to preserve potentially mycotoxigenic fungi, especially ochratoxin A and aflatoxins producers, which were isolated from food. Currently the CCDCA has more than 1000 isolates of Aspergillus, Penicillium, Cladosporium, Fusarium, Alternaria, Chaetomium, Mucor, Eurotium, and Neosartorya. A total of 66 species are represented which were isolated from food, cave environments, and soils of the Brazilian Atlantic Forest, Cerrado and Caatinga. A total of 328 cultures are preserved and maintained by periodic subculture, 137 by mineral oil preservation, and 550 by filter paper preservation. The staff trains graduate students in the taxonomy of major taxa of importance to agricultural research and food science. Finally, the CCDCA and UFLA, Brazil, in collaboration with the IBB-Biological Engineering Centre, Micoteca da Universidade do Minho, Portugal, intend to develop a project on polyphasic studies of Aspergillus and Penicillium isolated from various substrates, sources, and environments in Brazil. To pursue this aim CCDCA intends to: a) preserve Aspergillus and Penicillium strains for comparative studies between Brazilian regions and worldwide; b) foster the study of Aspergillus and Penicillium for biotechnological and toxigenic potential, and training in identification, preservation and distribution; c) establish quality control of fungal assays; and d) establish the CCDCA as a member of the global network of culture collections and participate in the international forums and organisations related to culture collections

Spatial distribution of wood volume in brazilian savannas

Here we model and describe the wood volume of Cerrado Sensu Stricto, a highly heterogeneous vegetation type in the Savanna biome, in the state of Minas Gerais, Brazil, integrating forest inventory data with spatial-environmental variables, multivariate regression, and regression kriging. Our study contributes to a better understanding of the factors that affect the spatial distribution of the wood volume of this vegetation type as well as allowing better representation of the spatial heterogeneity of this biome. Wood volume estimates were obtained through regression models using different environmental variables as independent variables. Using the best fitted model, spatial analysis of the residuals was carried out by selecting a semivariogram model for generating an ordinary kriging map, which in turn was used with the fitted regression model in the regression kriging technique. Seasonality of both temperature and precipitation, along with the density of deforestation, explained the variations of wood volume throughout Minas Gerais. The spatial distribution of predicted wood volume of Cerrado Sensu Stricto in Minas Gerais revealed the high variability of this variable (15.32 to 98.38 m3 ha-1) and the decreasing gradient in the southeast-northwest direction914COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESSem informaçã

Screening the PRISM Library against Staphylococcus aureus Reveals a Sesquiterpene Lactone from Liriodendron tulipifera with Inhibitory Activity

Infections caused by the bacterium Staphylococcus aureus continue to pose threats to human health and put a financial burden on the healthcare system. The overuse of antibiotics has contributed to mutations leading to the emergence of methicillin-resistant S. aureus, and there is a critical need for the discovery and development of new antibiotics to evade drug-resistant bacteria. Medicinal plants have shown promise as sources of new small-molecule therapeutics with potential uses against pathogenic infections. The principal Rhode Island secondary metabolite (PRISM) library is a botanical extract library generated from specimens in the URI Youngken Medicinal Garden by upper-division undergraduate students. PRISM extracts were screened for activity against strains of methicillin-susceptible S. aureus (MSSA). An extract generated from the tulip tree (Liriodendron tulipifera) demonstrated growth inhibition against MSSA, and a bioassay-guided approach identified a sesquiterpene lactone, laurenobiolide, as the active constituent. Intriguingly, its isomers, tulipinolide and epi-tulipinolide, lacked potent activity against MSSA. Laurenobiolide also proved to be more potent against MSSA than the structurally similar sesquiterpene lactones, costunolide and dehydrocostus lactone. Laurenobiolide was the most abundant in the twig bark of the tulip tree, supporting the twig bark’s historical and cultural usage in poultices and teas

Dinâmica da agricultura anual na região do Matopiba.

Considerando a importância de se conhecer a dinâmica do uso e cobertura da terra da região, este estudo mapeou a prática da agricultura anual com emprego de alta tecnologia, nos anos de 2005, 2010 e 2014, e estimou as taxas de expansão desta atividade nos diferentes períodos.SBSR 2015