Effect of magnesium on structure and properties of LiNbO3 prepared from polymeric precursors

The effect of magnesium addition on the phase formation and electric properties of LiNbO3 powder prepared from polymeric precursor was analyzed. It was shown that the unit-cell volume of the rhombohedral phase decreased with increasing magnesium concentration. Small amounts of secondary phases were observed in LiNbO3 powder doped with 5 and 10 mol% Mg+2. These results indicated that the Mg+2 ion was substituted for niobium ion in the rhombohedral phase. The addition of Mg+2 promotes densification of LiNbO3 ceramics. It was noticed that the increase in additive concentration leads to a decrease of electric properties, K-p and d(33). This is due to formation of LiNb3O8 and MgNb2O6 phases at the grain boundaries. (C) 2002 Elsevier B.V. Ltd and Techna S.r.l. All rights reserved.

Stock assessment and fishery management of the pink shrimp Farfantepenaeus brasiliensis Latreille, 1970 and F. paulensis Pérez-Farfante, 1967 in Southeastern Brazil (23° to 28° S)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Controle biológico da podridão radicular (Pythium aphanidermatum) e promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03 em alface hidropônica

Podridões radiculares causadas por espécies de Pythium são um importante problema em cultivos hidropônicos. Sintomas de subdesenvolvimento são observados nas plantas parasitadas pelo patógeno, sendo muitas vezes não diagnosticados pelo produtor. O objetivo do trabalho foi avaliar o controle biológico da podridão radicular causada por Pythium aphanidermatum e a promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03, reconhecidos agentes de controle biológico de doenças de plantas. A inoculação das plantas com P. aphanidermatum ocasionou o subdesenvolvimento, sendo essa diminuição de 20%. A adição dos agentes de biocontrole na solução nutritiva teve um efeito positivo no aumento da massa (6% a 13%), no número de folhas (4% a 7%) e no teor de clorofila (3%) das plantas de alface. Entretanto, maiores estudos devem ser realizados para melhorar a capacidade de controle da doença e de promoção de crescimento pelos agentes de biocontrole estudados no cultivo de alface hidropônica.

The compulsive-like aspect of the head dipping emission in rats with chronic electrolytic lesion in the area of the median raphe nucleus

Head dipping (HD) is a behavioral pattern considered to have a risk assessment or an exploratory role and is used as a complementary parameter to evaluate anxiety in experimental animals. Since rats with electrolytic lesion in the area of the median raphe nucleus displayed high frequencies of HD in a previous study, the present investigation was undertaken to confirm this observation and to determine its anxiety-related origin. HD episodes were counted in adult male Wistar rats (270-350 g) with electrolytic lesion (N = 11) and sham-lesioned controls (N = 12). When HD was measured for 60 min on an elevated open platform, lesioned rats emitted 13 times more HD than controls (264.7 ± 93.3 vs 20.3 ± 7.6 episodes), with the difference being statistically significant (P < 0.05). HD counts during 10-min sessions held 7, 14, 21, 27, and 63 days after lesion showed significantly higher means (range: 28.14 ± 5.38 to 62.85 ± 9.48) compared to sham-lesioned controls (range: 7.37 ± 1.13 to 8.5 ± 1.45). Normal rats stepped down into their home cages when the vertical distance between them and the cage was short (16 cm), and the step-down latencies increased with increasing depths (36.7 ± 7.92 to 185.87 ± 35.44 s). Lesioned rats showed a similar behavior when facing the shortest depth, but had a significantly increased number (23.28 ± 2.35 episodes) and latency (300 ± 0.00 s) of HD compared to normal rats (9.25 ± 1.37 episodes and 185.87 ± 35.44 s) when facing the greatest depth (30 cm). This suggests that HD may be a depth-measuring behavior related to risk assessment.

Idade materna como fator de risco: estudo com primigestas na faixa etária igual ou superior a 28 anos

Trata-se de estudo transversal, cujo objetivo foi analisar a idade materna como fator de risco ou não, através da verificação de intercorrências na gestação, parto e puerpério de primigestas com idade igual ou superior a 28 anos e das condições de nascimento e alta de seus recém-nascidos, comparando-as com o grupo de primigestas na faixa etária de 20 a 27 anos. Foi realizado em Botucatu/S.P., no período de janeiro de 1990 a junho de 1995. A análise estatística, discutida ao nível de 5% de significância, foi realizada através da prova de Mann-Whitney, teste de Goodman e avaliação do risco relativo e risco relativo corrigido, através da técnica de Mantel-Haenszel. Concluiu-se que a idade materna igual ou superior a 28 anos não constituiu fator de risco gestacional, puerperal e intra-parto mas, por outro lado, foi fator de risco, mesmo após controlado o tipo de parto, para as seguintes intercorrências perinatais: taquipnéia transitória do recém-nascido, cianose generalizada ao nascer e infecção neonatal.

Avaliação da vinhaça líquida em substituição à água na terminação de bovinos em confinamento 2. Parâmetros etológicos e perfil metabólico

Fifteen animals from Canchim group and fifteen from Nelore were observed in the following treatments: water (A), molasses soluble + magnesium oxide (V) and molasses soluble + magnesium oxide + sodium bicarbonate (V+B). They were observed during continuous 24 hours every 30 days up to 90 days periods. During the weighting, every 28 days blood samples were collected to determine metabolic outline. Treatments did not affect (P>.05) animal behaviour on metabolic and the obtained mean values were within the normal range. They were, respectively for Canchim and Nelore: Feeding 270 and 223 minutes; Rumination 374 and 356 minutes; Idleness 745 and 863 minutes; Glicose 86 and 88 mg/dl; Urea 10 and 23 mg/dl: Uric acid 1,3 and 1,2 mg/dl; Total protein 7,0 and 6,8 g/dl; Albumin 3,1 and 3,1 g/dl; Creatinin 1,5 and 1,6 mg/dl; Sodium 140 and 142 meq/dl; Potassium 4,2 and 4,3 meq/1 and Calcium 10,0 and 9,8 mg/dl. It was concluded that molasses soluble as a substitute of water has not changed the ethologic parameters neither metabolic outline of both genetic group when in finishing feedlot.

CONCERTED ACTION OF THE HIGH-AFFINITY CALCIUM-BINDING SITES IN SKELETAL-MUSCLE TROPONIN-C

Mutants of each of the four divalent cation binding sites of chicken skeletal muscle troponin C (TnC) were constructed using site directed mutagenesis to convert Asp to Ala at the first coordinating position in each site. With a view to evaluating the importance of site-site interactions both within and between the N- and C-terminal domains, in this study the mutants are examined for their ability to associate with other components of the troponin-tropomyosin regulatory complex and to regulate thin filaments. The functional effects of each mutation in reconstitution assays are largely confined to the domain in which it occurs, where the unmutated site is unable to compensate for the defect, Thus the mutants of sites I and II bind to the regulatory complex but are impaired in ability to regulate tension and actomyosin ATPase activity, whereas the mutants of sites III and IV regulate activity but are unable to remain bound to thin filaments unless Ca2+ is present. When all four sites are intact, free Mg2+ causes a 50-60-fold increase in TnC's affinity for the other components of the regulatory complex, allowing it to attach firmly to thin filaments. Calcium can replace Mg2+ at a concentration ratio of 1:5000, and at this ratio the Ca2 . TnC complex is more tightly bound to the filaments than the Mg2 . TnC form, In the C-terminal mutants, higher concentrations of Ca2+ (above tension threshold) are required to effect this transformation than in the recombinant wild-type protein, suggesting that the mutants reveal an attachment mediated by Ca2+ in the N-domain sites.

EFFECT OF CHOLINERGIC STIMULATION OF THE AMYGDALOID COMPLEX ON WATER AND SALT INTAKE

The effect of carbachol (80 nmol/mul) injection into the amygdaloid nuclear complex (AMG) on sodium appetite and water intake was studied in male Holtzman rats weighing 240-270 g. Twenty-five satiated rats and 38 water-deprived rats were used in the experiment on water intake. In the experiment on sodium intake, 19 rats were injected with atropine + carbachol and 9 rats with hexamethonium + carbachol. After carbachol injection into the AMG, water intake decreased in rats submitted to 30 h of water deprivation (10.28 +/- 1.04 ml/120 min vs 0.69 +/- 0.22 ml/120 min). The decrease in water intake was blocked by prior local injection of a tropine (20 nmol/1 mul)(11.66 +/- 1.46 ml/120 min vs 0.69 +/- 0.22 ml/120 min), but not of hexamethonium (30 nmol/1 mul), into the AMG. In water-deprived animals, carbachol injection into the AMG caused a decrease in sodium chloride intake (6.16 +/- 1.82 ml/h vs 0.88 +/- 0.54 ml/h) which was blocked by previous injection of hexamethonium but not of a tropine. These results suggest that the cholinergic system of the AMG plays a role in the control of water and salt intake.

Estimates of direct and maternal genetic effects for weights from birth to 600 days of age in Nelore cattle

Estimates of direct and maternal variance and heritability for weights at each week (up to 280 days of age) and month of age (up to 600 days of age) in Zebu cattle are presented. More than one million records on 200 000 animals, weighed every 90 days from birth to 2 years of age, were available. Data were split according to week (data sets 1) or month (data sets 2) of age at recording, creating 54 and 21 data sets, respectively. The model of analysis included contemporary groups as fixed effects, and age of dam (linear and quadratic) and age of calf (linear) effects as covariables. Random effects fitted were additive direct and maternal genetic effects, and maternal permanent environmental effect. Direct heritability estimates decreased from 0.28 at birth, to 0.12-0.13 at about 150 days of age, stayed more or less constant at 0.14-0.16 until 270 days of age and increased with age after that, up to 0.25-0.26. Maternal heritability estimates increased from birth (0.01) to a peak of 0.14 for data sets 1 and 0.07-0.08 for data sets 2 at about 180-210 days of age, before decreasing slowly to 0.07 and 0.05, respectively, at 300 days, and then rapidly diminished after 300 days of age. Permanent environmental effects were 1.5 to four times higher than genetic maternal effects and showed a similar trend.

Fluorescent amplified fragment length polymorphism (fAFLP) analyses and genetic diversity in Litopenaeus vannamei (Penaeidae)

The Pacific white shrimp, Litopenaeus vannamei (Penaeidae), represents about 95% of all Brazilian shrimp production. The Brazilian L. vannamei foundation broodstock was made up of specimens collected from different American Pacific sites, but little information was collected on the genetic structure of the broodstock. We used the fluorescence amplified fragment length polymorphism (fAFLP) method to study the genetic diversity of L. vannamei broodstock lines 03CMF1 and 03CBF1 originally produced by breeder-shrimps imported mainly from Panama and Ecuador, although wild individuals from other localities may also have been used in producing these two lines. Our results showed a total of 93 polymorphic bands ranging from 50 to 500 bp, the mean Nei's genetic diversity calculated for the total sample was 13.4% and identity and genetic distance analyses indicated high genetic homogeneity within and between both the broodstock lineages studied which suggests that they had similar genetic structure. These results may represent an important tool for the appropriate management of L. vannamei broodstocks. Copyright by the Brazilian Society of Genetics.

Efeito da sacarose e sorbitol na conservação in vitro de Passiflora giberti N. E. Brown

This work objectified the study of sucrose and sorbitol effect in the in vitro conservation for Passiflora giberti N. E. Brown, access. Therefore, an experiment was conducted in a completely randomized design to compare control treatment (standard MS) to MS medium supplemented with three sucrose concentrations (0, 15 and 30 g L -1) combined with three sorbitol concentrations (10, 20 and 40 g L -1), in a total of 10 treatments with 20 replicas. The experiment evaluation was carried out at 30, 60, 90 and 120 days of incubation, whereas the height of shoots (cm), number of roots, number and color of leaves were observed. The results showed the possibility to maintain passion-fruit microplants for a four months period under slow growth in MS medium supplemented with 10 or 20 g L -1 of sorbitol, without sucrose, and kept under 16 hours photoperiod (22 μ E m -2 s -1) and temperature of 27 ± 1°C. Sucrose sustained the longest development of the microplants. Root formation was affected by the sorbitol in the concentration of 40 g L -1 and by the absence of sucrose in the culture medium.

Incidência de malformações congênitas em crianças concebidas através de injeção intracitoplasmática de espermatozóides

Purpose: to evaluate the incidence and types of major congenital malformations (MCM) in liveborn children conceived by intracytoplasmic sperm injection (ICSI). Methods: a total of 680 liveborn children resulted from 511 couples submitted to ICSI from January, 1999 to December, 2002. Data collection of the children was performed through standardized questionnaire and clinical examination. Of the 511 couples, 366 had been contacted for a sampling of 371 gestations. Of the 680 liveborn, 520 had been evaluated, 250 of them (48.1%) through questionnaire and 270 (51.9%) through questionnaire and physical examination. Two hundred and fifty children were from singleton pregnancies and 270 from multiple pregnancies. Malformations were classified according to the 10th revision of the International Statistical Classification of Diseases and Related Health. Only MCM were analyzed in this study. The incidence of MCM was compared with that of the general population obtained by the Latin American Collaborative Study of Congenital Malformations. The statistical analysis was performed by the χ 2 test (level of significance p<0.05). Results: of the 520 children, 15 presented MCM, resulting in an incidence of 2.9%. There was no difference in relation to the control group (p>0.05), which showed 2.6% incidence of MCM. The most frequent malformations were of cardiac origin (four isolated and two associated), corresponding to 40% of the total. The other types of MCM were: renal (three), neural tube (two), skull (one), cleft lip (one), genital (one), Down syndrome (associated with cardiac malformations) (two), and musculoskeletal (one). Six MCM occurred in children from singleton pregnancies and nine in children from multiple pregnancies. Conclusion: the liveborn children conceived by ICSI presented incidence of major congenital malformations (2.9%) near to the expected for the general population (2.6%). However, to establish the risks of MCM with precision it is necessary to continue the evaluation of the children conceived by ICSI.