The young massive stellar cluster associated to RCW121

We report NIR broad and narrow band photometric observations in the direction of the IRAS17149-3916 source that reveal the presence of a young cluster of massive stars embedded in an HII region coincident with RCW121. These observations, together with published radio data, MSX and Spitzer images were used to determine some of the physical parameters of the region. We found 96 cluster member candidates in an area of about 1.5 x 2.0 square arcmin, 30% of them showing excess emission in the NIR. IRS 1, the strongest source in the cluster with an estimated spectral type of O5V-O6V ZAMS based on the color-magnitude diagram, is probably the main ionizing source of the HII region detected at radio wavelengths. Using the integrated Brgamma and the 5 GHz flux densities, we derived a mean visual extinction AV=5.49 magnitudes. From the observed size of the Brgamma extended emission, we calculated the emission measure E and the electron density ne, characteristic of compact HII regions.Comment: 18 pages, 8 figures, accepted for publication on AJ (February/2006

Amostragem de sementes para análise em laboratório.

bitstream/CNPH-2010/36436/1/ct-81.pd

Análise de sementes de hortaliças.

bitstream/CNPH-2010/36458/1/ct-83.pd

Dormência em sementes de hortaliças.

A presente revisão de literatura objetivou os fatores que induzem a dormência, as categorias e mecanismos de dormência, assim como, métodos para superar a dormência em sementes de hortaliças.bitstream/item/72481/1/doc-1361.pd

Peletização de sementes de hortaliças.

A presente revisão de literatura objetivou divulgar a técnica de peletização de sementes de hortaliças desenvolvida pela Embrapa Hortaliças, para melhorara a semeadura e/ou o desenvolvimento ou sobrevivência de espécies cultivads, a fim de reduzir os custos com as operações de transplante.bitstream/item/72475/1/doc-1371.pd

Avaliação de doenças da mangueira.

A região semi-árida do Vale do Submédio São Francisco é responsável por mais de 90% do volume de manga exportado pelo Brasil. esta região a produtividade é elevada devido a características climáticas favoráveis e ao manejo fitotécnico intenso. No entanto, a intensificação do cultivo e algumas práticas de manejo vêm gerando ou agravando problemas fitossanitários, com conseqüente aumento de perdas de produção. As doenças que ocorrem na mangueira resultam em perdas quantitativas, ou seja, menor número de frutos formado, mas principalmente perdas qualitativas (redução no tamanho e apodrecimento de frutos). Este tipo de perda pode prejudicar o trânsito internacional da manga desta região.bitstream/item/133830/1/ID-31564.pdfApostila distribuida aos participantes do Curso de Avaliação de Doenças da Mangueira, Petrolina, maio 2005

The true nature of the alleged planetary nebula W16-185

We report the discovery of a small cluster of massive stars embedded in a NIR nebula in the direction of the IRAS15411-5352 point source, which is related to the alleged planetary nebula W16-185. The majority of the stars present large NIR excess characteristic of young stellar objects and have bright counterparts in the Spitzer IRAC images; the most luminous star (IRS1) is the NIR counterpart of the IRAS source. We found very strong unresolved Brgamma emission at the IRS1 position and more diluted and extended emission across the continuum nebula. From the sizes and electron volume densities we concluded that they represent ultra-compact and compact HII regions, respectively. Comparing the Brgamma emission with the 7 mm free-free emission, we estimated that the visual extinction ranges between 14 and 20 mag. We found that only one star (IRS1) can provide the number of UV photons necessary to ionize the nebula.Comment: 30 pages, 15 figures, 2 tables V3: minor grammatical changes. Figure 4 is available in pdf file. Accepted for publication in AJ, April / 200

Nambu monopoles interacting with lattice defects in two-dimensional artificial square spin ice

The interactions between an excitation (similar to a pair of Nambu monopoles) and a lattice defect are studied in an artificial two-dimensional square spin ice. This is done by considering a square array of islands containing only one island different from all others. This difference is incorporated in the magnetic moment (spin) of the "imperfect" island and several cases are studied, including the special situation in which this distinct spin is zero (vacancy). We have shown that the two extreme points of a malformed island behave like two opposite magnetic charges. Then, the effective interaction between a pair of Nambu monopoles with the deformed island is a problem involving four magnetic charges (two pairs of opposite poles) and a string. We also sketch the configuration of the field lines of these four charges to confirm this picture. The influence of the string on this interaction decays rapidly with the string distance from the defect.Comment: 7 pages, 13 figure