And yet another method for the identification of modal constants in experimental modal analysis

Modal Identification from Frequency Response Functions (FRFs) is a chapter of Experimental Modal Analysis (EMA) that many would consider being closed in a book and covered in dust. Yet, in a previous paper from the same authors, a new approach to determine the modal damping factors from FRFs was proposed. Contrary to other modal identification methods which are based on the dynamic motion governing equations, the method used as a starting point the dissipated energy per cycle of vibration. For lightly damped systems with conveniently spaced modes, it produced quite accurate results, especially when compared to the method of the inverse. The method used a plot of the sine of the phase of the receptance against its amplitude, whereby damping was determined from the slope. In this paper, it will be shown that this plot has other special properties, whereby the real and imaginary parts of the modal constants can be determined from the plot through numerical extrapolation

Fermions in a warped resolved conifold

AbstractWe investigated the localization of the spinorial field in a braneworld built as a warped product between a 3-brane and a 2-cycle of the resolved conifold. This scenario provides a geometric flow that controls the singularity at the origin and changes the properties of the fermion in this background. Furthermore, due the cylindrical symmetry according to the 3-brane and a smoothed warp factor, this geometry can be regarded as a near brane correction of the string-like branes. This geometry allows a normalizable and well-defined massless mode whose decay and value on the brane depend on the resolution parameter. For the Kaluza–Klein modes, resolution parameter also controls the height of the barrier of the volcano potential

Anther Culture as a Supplementary Tool for Rice Breeding

There is a timely need to harness biotechnology and related tools to support conventional breeding strategies, overcoming the limitations in rice production and improving quantity and quality as well as climatic and disease stress tolerance of the crop. Anther culture allows immediate fixation of homozygosity through diploidization of regenerated haploid plants and therefore serves as an efficient path for inbred line development. Anther culture has been successfully used to hasten the breeding programs in several crop species including rice. However, associated constraints still prevent the realization of its full potential. Even though anther culture technique has been effective for Japonica rice breeding, applicability for Indica rice remains limited mainly due to inherent recalcitrant genetic background. Constraints associated with Indica rice can be identified as early anther necrosis, poor callus induction and proliferation, extremely low green plant regeneration and frequent albinism. Success of androgenesis is determined by factors such as genotype, physiological status of donor plant, pollen development stage at culture, composition and physical status of culture media, culture incubation conditions and anther pretreatments. This chapter has detailed out the scope for improving the applicability of anther culture technique on rice in order to develop it as a supplementary breeding tool

Population expansion in the North African Late Pleistocene signalled by mitochondrial DNA haplogroup U6

Background <br/> The archaeology of North Africa remains enigmatic, with questions of population continuity versus discontinuity taking centre-stage. Debates have focused on population transitions between the bearers of the Middle Palaeolithic Aterian industry and the later Upper Palaeolithic populations of the Maghreb, as well as between the late Pleistocene and Holocene. <br/> Results Improved resolution of the mitochondrial DNA (mtDNA) haplogroup U6 phylogeny, by the screening of 39 new complete sequences, has enabled us to infer a signal of moderate population expansion using Bayesian coalescent methods. To ascertain the time for this expansion, we applied both a mutation rate accounting for purifying selection and one with an internal calibration based on four approximate archaeological dates: the settlement of the Canary Islands, the settlement of Sardinia and its internal population re-expansion, and the split between haplogroups U5 and U6 around the time of the first modern human settlement of the Near East. <br/> Conclusions <br/> A Bayesian skyline plot placed the main expansion in the time frame of the Late Pleistocene, around 20 ka, and spatial smoothing techniques suggested that the most probable geographic region for this demographic event was to the west of North Africa. A comparison with U6's European sister clade, U5, revealed a stronger population expansion at around this time in Europe. Also in contrast with U5, a weak signal of a recent population expansion in the last 5,000 years was observed in North Africa, pointing to a moderate impact of the late Neolithic on the local population size of the southern Mediterranean coast

On the use of controlled radiation pressure to send a satellite to a graveyard orbit

A very important topic in modern astrodynamics is the removal of satellites from their orbits, after the end of their missions. In this work, we propose the use of the solar radiation pressure to change the orbital energy of a satellite, to remove it from the operational region to a graveyard orbit. A mechanism for changing the area-to-mass ratio of the satellite and/or its reflectivity coefficient is used to accomplish this task. We derive an analytical model to find the maximum eccen- tricity achieved during the removal trajectory, for different initial conditions for the argument of perigee and the longitude of the ascending node. After that, the best trajectories, i.e., trajectories with low eccentricity, are integrated using a numerical model. These low eccentricity trajectories are important because satellites with disposal orbits with low eccentricity pose a lower risk of crossing the operational region during the de-orbiting.Un tema importante en la astrodinámica moderna es la remoción de satélites de sus órbitas al finalizar sus misiones. En este trabajo proponemos utilizar la presión de la radiación solar para modificar la energía orbital del satélite, y así alejarlo de la región operacional y enviarlo a una órbita “en el cementerio”. Para este propósito, se propone un mecanismo para cambiar la razón área-masa y/o la reflectividad del satélite. Obtenemos un modelo analítico para encontrar la máxima excentricidad alcanzada durante la trayectoria de remoción, para diferentes valores iniciales del argumento del perigeo y de la longitud del nodo ascendente. A continuación, las mejores trayectorias, esto es, las de menor excenticidad, se integran numéricamente. Estas trayectorias de baja excentricidad son importantes pues los satélites con ´orbitas de desecho de baja excentricidad tienen un menor riesgo de cruzar las regiones operacionales durante su eliminación.The author is thankful for the grants # 406841/2016-0 and 301338/2016-7 from the National Council for Scientific and Technological Development (CNPq); and grants # 2014/22295-5, 2011/08171-3, 2016/14665-2 and 2016/07248-6 from São Paulo Research Foundation (FAPESP).info:eu-repo/semantics/publishedVersio

In Vitro Cytotoxicity Assays Of Solid Lipid Nanoparticles In Epithelial And Dermal Cells

In recent years, the interest in nanostructured systems to drug delivery has increased because they offer several advantages over conventional dosage forms. Solid Lipid Nanoparticles (SLN) have been highlighted among these systems because they have advantages such as high physical stability, protection against drug degradation and ease of scale-up and manufacturing, without using organic solvent. The aim of this work was to evaluate the potential of SLN, by in vitro cytotoxicity assays, for dermal drug delivery. SLN of three different lipids were prepared by hot high pressure homogenization and the cytotoxicity was assessed by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test in mouse 3T3 fibroblasts and human HaCaT keratinocytes. SLN showed no cytotoxic potential suggesting a great potential for dermal application.3041Mishra, B., Patel, B.B., Tiwari, S., (2010) Nanomed.-Nanotechnol. Biol. Med., 6, p. 9Mehnert, W., Mäder, K., (2001) Adv. Drug Deliv. Rev., 47, p. 165Pardeike, J., Hommoss, A., Müller, R.H., (2009) Int. J. Pharm., 366, p. 170Lewinski, N., Colvin, V., Drezek, R., (2008) Small, 4, p. 26Schöler, N., Hahn, H., Müller, R.H., Liesenfeld, O., (2002) Int. J. Pharm., 231, p. 167Müller, R.H., Maassen, S., Schwarz, C., Mehnert, W., (1997) J. Control. Release, 47, p. 261Shöler, N., Hahn, H., Müller, R.H., Liesenfeld, O., (2002) Int. J. Pharm., 231, p. 167Weyenberg, W., Filev, P., Plas, D.V., Vandervoort, J., Smet, K.D., Sollie, P., Ludwig, A., (2007) Int. J. Pharm., 337, p. 291Kristl, J., Teskac, K., Milek, M., Rascan, I.M., (2008) Toxicol. Appl.Pharmacol., 232, p. 218Mosmann, T., (1983) J. Immunol. Methods, 65, p. 55Marcato, P.D., Caverzan, J., Rossi-Bergmann, B., Pinto, E.F., MacHado, D., Silva, R.A., Justos, G.Z., Durán, N., (2011) J. Nanosci. Nanotechnol

Genetic diversity among air yam (dioscorea bulbifera) varieties based on single sequence repeat markers

Dioscorea is the largest genus in the Dioscoreaceae family, and includes a number of economically important species including the air yam, D. bulbifera L. This study aimed to develop new single sequence repeat primers and characterize the genetic diversity of local varieties that originated in several municipalities of Brazil. We developed an enriched genomic library for D. bulbifera resulting in seven primers, six of which were polymorphic, and added four polymorphic loci developed for other Dioscorea species. This resulted in 10 polymorphic primers to evaluate 42 air yam accessions. Thirty-three alleles (bands) were found, with an average of 3.3 alleles per locus. The discrimination power ranged from 0.113 to 0.834, with an average of 0.595. Both principal coordinate and cluster analyses (using the Jaccard Index) failed to clearly separate the accessions according to their origins. However, the 13 accessions from Conceição dos Ouros, Minas Gerais State were clustered above zero on the principal coordinate 2 axis, and were also clustered into one subgroup in the cluster analysis. Accessions from Ubatuba, São Paulo State were clustered below zero on the same principal coordinate 2 axis, except for one accession, although they were scattered in several subgroups in the cluster analysis. Therefore, we found little spatial structure in the accessions, although those from Conceição dos Ouros and Ubatuba exhibited some spatial structure, and that there is a considerable level of genetic diversity in D. bulbifera maintained by traditional farmers in Brazil152CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPnão tem2007/04805-