Pion and Vector Meson Form Factors in the Kuperstein-Sonnenschein holographic model

We study phenomenological aspects of the holographic model of chiral symmetry breaking recently introduced by Kuperstein and Sonnenschein (KS). As a first step, we calculate the spectrum of vector and axial-vector mesons in the KS model. We numerically compute various coupling constants of the mesons and pions. Our analysis indicates that vector meson dominance is realized in this model. The pion, vector meson and axial-vector meson form factors are obtained and studied in detail. We find good agreement with QCD results. In particular, the pion form factor closely matches available experimental data.Comment: v1: 27 pages, 9 figures, 4 tables; v2: minor changes, added more general discussion of vector meson dominance; v3: minor changes and additions, version accepted for publication in JHE

Scalar and vector mesons of flavor chiral symmetry breaking in the Klebanov-Strassler background

Recently, Dymarsky, Kuperstein and Sonnenschein constructed an embedding of flavor D7- and anti-D7-branes in the Klebanov-Strassler geometry that breaks the supersymmetry of the background, yet is stable. In this article, we study in detail the spectrum of vector mesons in this new model of flavor chiral symmetry breaking and commence an analytical analysis of the scalar mesons in this setup.Comment: v1: 35 pages, 5 figures, 4 tables, includes self-contained review of DKS construction; v2: corrected signs in eqs. (2.22) and (2.23), improved discussion of scalar mesons in section 3.2; v3: major revision of the results on scalar mesons, version submitted to JHEP; v4: version accepted by JHE

Infection process and host defense responses in compatible and incompatible interactions between Cowpea (Vigna unguiculata) and Colletotrichum gloeosporioides.

The infection process of Colletotrichum gloeosporioides was examined by light microscopy on two cowpea genotypes, BR 3 Tracuateua and TE 97-411. In the susceptible genotype BR 3 Tracuateua, the pathogen acted as an intracellular hemibiotroph. Invasion of cowpea primary leaves occurred preferentially through the leaf epidermal cells by penetration tubes that emerged from appressoria. The penetration tube swelled within 48 h to form a spherical infection vesicle inside the epidermal cell in a biotrophic interaction. Subsequently, it became multilobed and multiseptated. By 4 d after inoculation, one or more large primary hyphae emerged from the lateral lobes and grew intracellularly and further colonized several adjacent epidermal host cells, characterizing the necrotrophic phase of infection. Primary leaves of the resistant cowpea genotype, TE 97-411, showed enhanced penetration resistance to C. gloeosporioides associated with higher epidermal H2O2 accumulation beneath appressoria and primary germ tubes, papilla formation, and increased phenylalanine ammonia-lyase activity, possibly related to accumulation of phenolic compounds and host cell wall lignification. Macroscopic examination of the primary leaves revealed the presence of shrunken necrotic lesions characteristic of anthracnose in infected BR 3 Tracuateua, whereas in the genotype TE 97-411, cell death was also observed but only in a reduced percentage of the infection sites. In summary, the results obtained in this study suggested that TE 97-411 is the resistant genotype to C. gloeosporioides compared with BR 3 Tracuateua because it developed more effective defense responses against the establishment of the pathogen

Effect of presence of corpus luteum at the time of follicular aspiration on oocyte recovery and in vitro competence in Bos indicus cattle.

Edição dos resumos da 20ª Reunião Anual da Sociedade Brasileira de Tecnologia de Embriões, Araxá, 2006

Effect of maternal heat-stress on follicular growth and oocyte competence in Bos indicus cattle.

The objective was to determine whether exposure of Gir (Bos indicus) cows to heat-stress (HS) causes immediate and delayed deleterious effect on follicular dynamics, hormonal profile and oocyte competence. The cows were kept in tie-stalls for an adaptive thermoneutral period of 28 days (Phase I, Days −28 to −1). In Phase II (Days 0–28) cows were randomly allocated into control (CG, n = 5) and HS (HS, n = 5) treatments. The HS cows were placed in an environmental chamber at 38 °C and 80% relative humidity (RH) during the day and 30 °C, 80% RH during the night for 28 days. The CG group was maintained in shaded tie-stalls (ambient temperature) for 28 days. During Phase III (Days 28–147) animals were placed in tie-stalls (Days 28–42) followed by pasture (Days 42–147) under thermoneutrality. In each phase, weekly ovum pick up (OPU) sessions were to evaluate follicular development, morphology of cumulus–oocyte complexes (COCs), and developmental competence after in vitro maturation, fertilization, and culture. Serum concentrations of progesterone (P4) and cortisol were evaluated by radioimmunoassay. Exposure of Gir cows to HS had no immediate effect on reproductive function, but exerted a delayed deleterious effect on ovarian follicular growth, hormone concentrations, and oocyte competence. Heat-stress increased the diameter of the first and second largest follicles from Days 28 to 49. Indeed, HS increased the number of >9 mm follicles (characterized as follicular codominance) during this phase. Cows exposed to HS had longer periods of non-cyclic activity (P4 < 1 ng/mL), as well as shorter estrous cycles. However, HS did not affect cortisol concentration as compared to CG. Although HS had no significant effect on cleavage rate, it reduced blastocyst development during Phase III. In conclusion, long-term exposure of B. indicus cattle to HS had a delayed deleterious effect on ovarian follicular dynamics and oocyte competence

Effect of follicular codominance at the time of follicular aspiration on the recovery and in vitro competence of oocytes in Bos indicus cattle.

Edição dos resumos da 20ª Reunião Anual da Sociedade Brasileira de Tecnologia de Embriões, Araxá, 2006

Effect of maternal heat stress on oocyte quality and in vitro competence in Bos indicus cattle.

Edição dos resumos da 20ª Reunião Anual da Sociedade Brasileira de Tecnologia de Embriões, Araxá, 2006

Qualidade sanitária e fisiológica de sementes de abóbora variedade menina Brasileira.

O trabalho teve como objetivos avaliar e correlacionar a qualidade sanitária e fisiológica de sementes de abóbora, variedade Menina Brasileira (Cucurbita moschata.). Foram avaliados dois lotes de sementes de abóbora produzidas no sistema agroecológico e quatro no sistema convencional, com e sem tratamento químico. Os lotes foram submetidos aos testes de sanidade, seguindo a metodologia do “Blotter test”, com congelamento, germinação e vigor (primeira contagem, índice de velocidade de germinação, envelhecimento acelerado e emergência de plântulas). Os resultados indicaram a separação dos lotes de diferentes origens a partir da qualidade sanitária e fisiológica, onde as maiores incidências de fungos foram observadas nos lotes agroecológicos e o maior potencial fisiológico foi observado nos lotes de origem convencional não tratados. Foram encontrados os fungos Fusarium oxysporum, Alternaria alternata, Cladosporium cucumerinum, Aspergillus niger, Penicillium digitatum, Rhizopus stolonifer e Phoma terrestris. A qualidade sanitária não interferiu na qualidade fisiológica das sementes de abóbora, variedade Menina Brasileira