Pillared graphene oxide composite as an adsorbent of soluble hydrocarbons in water: pH and organic matter effects.

Graphene oxide (GO) is a single-atom-thick sheet of carbon with oxygen-containing functional groups decorating its basal plane and edge sites. Most of its high surface area can be lost due to restacking of individual layers during the synthesis and drying of GO-based bulk sorbents. There is great interest to increase the specific surface area of graphene-based sorbents by introducing organic molecules as "pillaring agents" between GO sheets to hinder the stacking process and create sorbents with elevated surface area. This work synthesizes pillared GO by introducing chitosan (CS), a linear polysaccharide with various molecular weights. A composite of low molecular weight CS at a CS/GO ratio of 0.1 is shown to have the highest specific surface area (up to 70.5 m2/g) in comparison to the medium and high CS molecular weight, pristine GO, and the CS/GO composite materials. The affinity of the optimized GO/CS composites towards benzene, toluene, and naphthalene was evaluated at 19.3 mg/L of organic matter content while altering pH. Sips and Langmuir adsorption isotherm models well described the adsorption behavior, and benzene adsorption performance was reduced at low pH. Related to the presence of dissolved organic matter (DOM) in solution, lower diffusivity constants (k1) in hydrocarbon systems were recorded. Our results demonstrate the feasibility of CS as a potential pillaring agent in CS/GO composites to increase specific surface area and enhance the capture of soluble hydrocarbons from aqueous solutions.

Supplementation with sunflower seeds in beef cattle did not impact on oocyte and in vitro embryo production.

Supplementation with compounds rich in linoleic acid, including sunflower seed supplementation, promotes increase in conception rates in cows. We aimed to evaluate whether the sunflower seed (linoleic acid source) supplementation in beef donor females alters the plasma concentrations of cholesterol, triglycerides, HDL and LDL, increases the number and quality of oocytes, increases the cleavage rates and determines an improvement in number and quality of in vitro produced blastocysts. Thus, Nelore females were divided into two groups of 15 animals to receive supplementation with or without sunflower seed for 57 days. Females underwent follicular aspiration and the oocytes were subjected to in vitro embryo production. There was no difference (p > .1) between control group and group supplemented with sunflower seed on the number of displayed follicles; number of aspired oocytes; recovery rate; cleavage rate; number of embryos; number of blastocysts; embryos number of grades I and II; plasma concentrations of total cholesterol, triglycerides; HDL and LDL. Therefore, sunflower seed supplementation in oocyte donors did not increase the number and quality of oocytes, cleavage rates and the number and quality of blastocysts produced in vitro.

Persistent effects of pre-Columbian plant domestication on Amazonian forest composition.

The extent to which pre-Columbian societies altered Amazonian landscapes is hotly debated. We performed a basin-wide analysis of pre-Columbian impacts on Amazonian forests by overlaying known archaeological sites in Amazonia with the distributions and abundances of 85 woody species domesticated by pre-Columbian peoples. Domesticated species are five times more likely than nondomesticated species to be hyperdominant. Across the basin, the relative abundance and richness of domesticated species increase in forests on and around archaeological sites. In southwestern and eastern Amazonia, distance to archaeological sites strongly influences the relative abundance and richness of domesticated species. Our analyses indicate that modern tree communities in Amazonia are structured to an important extent by a long history of plant domestication by Amazonian peoples.

Tuning band inversion symmetry of buckled III-Bi sheets by halogenation.

First-principles calculations are employed to investigate structural, electronic and topological insulating properties of XBi (X = B, Al, Ga, and In) monolayers upon halogenation. It is known that Y-XBi (X = Ga, In, Tl; Y = F, Cl, Br, I) can originate inversion-asymmetric topological insulators with large bulk band gaps. Our results suggest that Y-XBi (X = B, Al; Y = F, Cl, Br, I) may also result in nontrivial topological insulating phases. Despite the lower atomic number of B and Al, the spin-orbit coupling opens a band gap of about 400 meV in Y-XBi (X = B, Al), exhibiting an unusual electronic behavior for practical applications in spintronics. The nature of the bulk band gap and Dirac-cone edge states in their nanoribbons depends on the group-III elements and Y chemical species. They lead to a chemical tunability, giving rise to distinct band inversion symmetries and exhibiting Rashba-type spin splitting in the valence band of these systems. These findings indicate that a large family of Y-XBi sheets can exhibit nontrivial topological characteristics, by a proper tuning, and open a new possibility for viable applications at room temperature.

Spin-orbit-induced gap modification in buckled honeycomb XBi and XBi3 (X = B, Al, Ga, and In) sheets.

The band structure and stability of XBi and XBi3 (X = B, Al, Ga, and In) single sheets are predicted using first-principles calculations. It is demonstrated that the band gap values of these new classes of two-dimensional (2D) materials depend on both the spin-orbit coupling (SOC) and type of group-III elements in these hetero-sheets. Thus, topological properties can be achieved, allowing for viable applications based on coherent spin transport at room temperature. The spin-orbit effects are proved to be essential to explain the tunability by group-III atoms. A clear effect of including SOC in the calculations is lifting the spin degeneracy of the bands at the Γ point of the Brillouin zone. The nature of the band gaps, direct or indirect, is also tuned by SOC, and by the appropriate X element involved. It is observed that, in the case of XBi single sheets, band inversions naturally occur for GaBi and InBi, which exhibit band gap values around 172 meV. This indicates that these 2D materials are potential candidates for topological insulators. On the contrary, a similar type of band inversion, as obtained for the XBi, was not observed in the XBi3 band structure. In general, the calculations, taking into account SOC, reveal that some of these buckled sheets exhibit sizable gaps, making them suitable for applications in room-temperature spintronic devices.

Insights about the genetic diversity and population structure of an offshore group of common bottlenose dolphins (Tursiops truncatus) in the Mid-Atlantic.

Although the genus Tursiops has a worldwide distribution and is globally well-studied, some dolphin populations continue to face high risks of decline. Hence, it is necessary to assess the genetic diversity and structure of this genus to properly assess its conservation status and to implement appropriate management actions. In Brazil, genetic studies on this group remain rare, particularly for populations inhabiting offshore waters. Saint Peter and Saint Paul Archipelago (SPSPA) is a small group of islands located in the Mid- Atlantic Ridge, where recent studies of the Tursiops truncatus group indicate that individuals are resident throughout the year around the archipelago, exhibiting considerable site fidelity. A previous study with this group indicated that the individuals form an isolated population. To test this hypothesis, and describe the genetic diversity of SPSPA individuals, we assessed 12 microsatellite loci and a portion of the mitochondrial control region. Bayesian analysis revealed that SPSPA bottlenose dolphins form a unique population. In a phylogeographic perspective, we found that individuals from SPSPA shared mtDNA haplotypes with inshore and offshore individuals from North Atlantic, suggesting that they are not currently isolated from their conspecifics. Mirroring mtDNA findings, microsatellite analysis revealed that most of the pairs of individuals sampled seem to be unrelated (83.8%) and no indication of inbreeding, what would be expected if a small population such as SPSPA was reproductively isolated.

Long-term decline of the Amazon carbon sink.

Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.

Hybrid platforms of graphane-graphene 2D structures: prototypes for atomically precise nanoelectronics.

First-principles calculations demonstrate that line/ribbon defects, resulting from a controlled dehydrogenation in graphane, lead to the formation of low-dimensional electron-rich tracks in a monolayer. The present simulations point out that hybrid graphane-graphene nanostructures exhibit important elements, greatly required for the fabrication of efficient electronic circuits at the atomic level.

Height distribution of equipotential lines in a region confined by a rough conducting boundary.

This work considers the behavior of the height distributions of the equipotential lines in a region confined by two interfaces: a cathode with an irregular interface and a distant flat anode. Both boundaries, which are maintained at distinct and constant potential values, are assumed to be conductors. The morphology of the cathode interface results from the deposit of 2 × 10(4) monolayers that are produced using a single competitive growth model based on the rules of the Restricted Solid on Solid and Ballistic Deposition models, both of which belong to the Kadar-Parisi-Zhang (KPZ) universality class. At each time step, these rules are selected with probability p and q = 1 - p. For several irregular profiles that depend on p, a family of equipotential lines is evaluated. The lines are characterized by the skewness and kurtosis of the height distribution. The results indicate that the skewness of the equipotential line increases when they approach the flat anode and this increase has a non-trivial convergence to a delta distribution that characterizes the equipotential line in a uniform electric field. The morphology of the equipotential lines is discussed; the discussion emphasizes their features for different ranges of p that correspond to positive, null and negative values of the coefficient of the non-linear term in the KPZ equation.

Effects of sex and genotype on performance and yield characteristics of free range broiler chickens / Avaliação dos efeitos de sexo e genótipo sobre características de desempenho e rendimento em frangos tipo caipira

The purpose of this work was to evaluate the effect of genotype and sex on the performance characteristics (weight gain, feed conversion and livability) and yields (carcass, breast and legs) of six free-range genotypes: Pesadão Vermelho (GEN1), Carijó (GEN2), Pescoço Pelado 1 (GEN3), Pescoço Pelado 2 (GEN4), Pescoço Pelado 3 (GEN5) and Pescoço Pelado 4 (GEN6). A total of 1584 sexed one day old chicks (792 males and 792 females) were housed in 48 pens, 33 birds per pen. The experimental design was a completely randomized factorial 2 x 6 (six genotypes and two sexes) design, with four replicates each. Diets were based on corn and soybean meal (no animal protein) provided in a feeding program in four phases: pre-starter (1 to 21 days), starter (22 to 42 days), growth (43 to 77 days) and finisher (78 to 91 days). Feed intake, feed conversion and livability were measured at 21, 42, 77 and 91 days of age. There was no genotype x sex interaction. The effect of sex was observed in all ages regarding weight gain, feed conversion (except at 21 days) and yields. For all these characteristics, males performed better than females, except in breast yield, which was higher in females. For the livability and feed conversion at 21 days no effect of sex was found. The effect of genotype was observed only in carcass and breast yields. The fast (GEN1) and intermediate (GEN2, GEN5 and GEN6) growing genotypes showed higher weight gain than the slow growing genotypes (GEN4 and GEN3). Carcass and breast yields of naked neck genotypes (GEN3, GEN4, GEN5 and GEN6) did not differ among themselves, and were higher than the Carijó genotype (GEN2) and are therefore recommended for production systems that sell industrialized birds.

A realização deste trabalho buscou avaliar o efeito de genótipo, sexo e sua interação sobre as características de desempenho (ganho de peso, conversão alimentar e viabilidade) e de rendimento (carcaça, peito e pernas) de seis genótipos de frango de corte tipo caipira: Pesadão Vermelho (GEN1), Carijó (GEN2), Pescoço Pelado 1 (GEN3), Pescoço Pelado 2 (GEN4), Pescoço Pelado 3 (GEN5) e Pescoço Pelado 4 (GEN6). Foram utilizados 1584 pintinhos sexados (792 machos e 792 fêmeas), alojados em 48 boxes, sendo 33 aves por boxe. O delineamento experimental foi o inteiramente ao acaso, em esquema fatorial 6 x 2 (seis genótipos e dois sexos), com quatro repetições cada, sendo cada boxe considerado uma unidade experimental. As rações à base de milho e farelo de soja (sem proteínas de origem animal) foram fornecidas em um programa de alimentação de quatro fases:pré-inicial (um a 21 dias), inicial (22 a 42 dias), crescimento (43 a 77 dias) e abate (78 dias até o abate). As variáveis foram medidas aos 21, 42, 77 e 91 dias de idade. Não foi observado efeito da interação sexo x genótipo. Foi observado efeito de sexo, em todas as idades avaliadas para ganho de peso, conversão alimentar (exceto aos 21 dias) e rendimentos. Para todas essas características, os machos apresentaram melhor desempenho que as fêmeas, exceto no rendimento de peito. Para a viabilidade e a conversão alimentar aos 21 dias não foi encontrado efeito de sexo. Efeito de genótipo foi observado apenas nas características ganho de peso e rendimento de carcaça e peito. Os genótipos de crescimento rápido (GEN1) e intermediário (GEN2, GEN5 e GEN6) apresentaram melhor desempenho em relação a ganho de peso do que os genótipos de crescimento lento (GEN3 e GEN4). Para o rendimento de carcaça e peito, os genótipos de Pescoço Pelado (GEN3, GEN4, GEN5 e GEN6) não diferiram entre si e apresentaram rendimentos maiores que o genótipo Carijó (GEN2), sendo recomendáveis para sistemas de produção que vendem aves industrializadas.

Effect of the local morphology in the field emission properties of conducting polymer surfaces.

In this work, we present systematic theoretical evidence of a relationship between the point local roughness exponent (PLRE) (which quantifies the heterogeneity of an irregular surface) and the cold field emission properties (indicated by the local current density and the macroscopic current density) of real polyaniline (PANI) surfaces, considered nowadays as very good candidates in the design of field emission devices. The latter are obtained from atomic force microscopy data. The electric field and potential are calculated in a region bounded by the rough PANI surface and a distant plane, both boundaries held at distinct potential values. We numerically solve Laplace's equation subject to appropriate Dirichlet's condition. Our results show that local roughness reveals the presence of specific sharp emitting spots with a smooth geometry, which are the main ones responsible (but not the only) for the emission efficiency of such surfaces for larger deposition times. Moreover, we have found, with a proper choice of a scale interval encompassing the experimentally measurable average grain length, a highly structured dependence of local current density on PLRE, considering different ticks of PANI surfaces.

Distribution of scaled height in one-dimensional competitive growth profiles.

This work investigates the scaled height distribution, ρ(q), of irregular profiles that are grown based on two sets of local rules: those of the restricted solid on solid (RSOS) and ballistic deposition (BD) models. At each time step, these rules are respectively chosen with probability p and r=1-p. Large-scale Monte Carlo simulations indicate that the system behaves differently in three succeeding intervals of values of p: I(B) ≈ [0,0.75),I(T) ≈ (0.75,0.9), and I(R) ≈ (0.9,1.0]. In I(B), the ballistic character prevails: the growth velocity υ(∞) decreases with p in a linear way, and similar behavior is found for Γ(∞) (p), the amplitude of the t(1/3)-fluctuations, which is measured from the second-order height cumulant. The distribution of scaled height fluctuations follows the Gaussian orthogonal ensemble (GOE) Tracy-Widom (TW) distribution with resolution roughly close to 10(-4). The skewness and kurtosis of the computed distribution coincide with those for TW distribution. Similar results are observed in the interval I(R), with prevalent RSOS features. In this case, the skewness become negative. In the transition interval I(T), the system goes smoothly from one regime to the other: the height distribution becomes apparently Gaussian, which motivates us to identify this phenomenon as a transition from Kardar-Parisi-Zhang (KPZ) behavior to Edwards-Wilkinson (EW) behavior back to KPZ behavior.

DFT studies of the interactions of a graphene layer with small water aggregates.

We have investigated the structure, adsorption, electronic states, and charge transfer of small water aggregates on the surface of a graphene layer using density functional theory. Our calculations were focused on water adsorbates containing up to five water molecules interacting with one and both sides of a perfect freestanding sheet. Different orientations of the aggregates with respect to the graphene sites were considered. The results show that the adsorption energy of one water molecule is primarily determined by its orientation, although it is also strongly dependent on the implemented functional scheme. Despite its intrinsic difficulties with dispersion interactions, the Perdew and Wang's exchange-correlation functional may be a viable alternative to investigate the adsorption of large molecular aggregates on a graphene surface. Although water physisorption is expected to occur in the regime of droplets, we found no induced impurity states close to the Fermi level of graphene interacting with small water clusters. In order to investigate the donor/acceptor tendency of the water clusters on graphene, we have performed a Bader charge analysis. Considering the charge transfer mechanism, we have noticed that it should preferentially occur from water to graphene only when the oxygen atom is pointing toward the surface. Otherwise, and in the case of larger adsorbed clusters, charge transfers systematically occur from graphene to water.

Recém-nascido pequeno para a idade gestacional: repercussão nas habilidades motoras finas / Small-for-gestational-age newborn infant: repercussion on fine motor skills

OBJETIVO: Comparar as habilidades motoras finas de lactentes nascidos a termo pequenos para a idade gestacional (PIG) com as habilidades dos nascidos adequados para a idade gestacional (AIG) no terceiro mês de vida. MÉTODOS: Realizou-se um estudo observacional de corte transversal. Avaliaram-se 67 lactentes (21 PIG e 46 AIG) no terceiro mês de vida. Portadores de síndromes genéticas, malformações congênitas, infecções congênitas e aqueles que necessitaram de unidade de terapia intensiva neonatal foram excluídos. As Escalas Bayley II de Desenvolvimento Infantil foram utilizadas, com ênfase nos itens que avaliam as habilidades motoras finas. RESULTADOS: Não se observaram diferenças entre os grupos na escala motora (p=0,21) e mental (p=0,45) no terceiro mês de vida. No item "Alcança o Aro Suspenso", houve diferença significativa (teste Exato de Fisher; p=0,02), demonstrando maior frequência de execução para o grupo PIG no terceiro mês de vida. CONCLUSÕES: Supõe-se que a diferença encontrada no item "Alcança o Aro Suspenso" possa ser atribuída à grande ocorrência de movimentos dos braços observada no grupo PIG e não a uma condição melhor de desenvolvimento desse grupo.

OBJECTIVE: To compare the fine motor skills of full-term small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) infants in the third month of life. METHODS: This observational cross-sectional study enrolled 67 infants (21 SGA and 46 AGA) in the third month of life. Infants presenting genetic syndromes, congenital malformations, congenital infections and those who needed neonatal intensive care were excluded. The Bayley Scales of Infant Development-II were used, with emphasis on items that evaluate the fine motor skills. RESULTS: No differences were observed between groups for motor (p=0.21) and mental (p=0.45) scales in the third month. There was a significant difference between the groups on the item "Reaches for Suspended Ring" (Fisher's exact test; p-value=0.02): a higher percentage of SGA infants accomplished this item in the third month of life. CONCLUSIONS: We hypothesize that the difference found in the item "Reaches for Suspended Ring" could be attributed to an increased frequency of arm movements observed in SGA infants and not to a better neurodevelopment of this group.

OBJETIVO: Comparar las habilidades motoras finas de lactantes nacidos a término pequeños para la edad gestacional (PEG) con adecuados para la edad gestacional (AEG) en el 3er mes de vida. MÉTODOS: Se realizó un estudio observacional de corte transversal. Se evaluaron a 67 lactantes (21 PEG y 46 AEG) en el 3er mes de vida. Síndromes genéticos, malformaciones congénitas, infecciones congénitas y aquellos que necesitaron de unidad de terapia intensiva neonatal fueron excluidos. Las Escalas Bayley II y de Desarrollo Infantil fueron utilizadas, con énfasis en los ítems que evalúan las habilidades motoras finas. RESULTADOS: No se observaron diferencias entre los grupos en la escala motora (p=0,21) y mental (p=0,45) en el 3er mes de vida. En el ítem "alcanza aro suspendido" hubo diferencia significativa (p=0,02; prueba Exacta de Fisher), demostrando mayor frecuencia de ejecución para el grupo PEG en el 3er mes de vida. CONCLUSIONES: Se supone que la diferencia encontrada en el ítem "alcanza el aro suspendido" pueda ser atribuida a la gran ocurrencia de movimientos de los brazos observada en el grupo PEG y no a una condición mejor de desarrollo en este grupo.

Desempenho motor de lactentes frequentadores de berçários em creches públicas / Motor performance of infants attending the nurseries of public day care centers

OBJETIVO: Analisar o desempenho motor axial, apendicular e global e sua correlação com as características neonatais, familiares e de tempo de exposição à creche em crianças com idade entre 12-24 meses, frequentadoras de creches públicas. MÉTODOS: Estudo transversal com 40 lactentes (idade média 14,3±2,4 meses) frequentadores de creches públicas. Os participantes foram avaliados quanto ao desempenho motor com a Bayley Scales of Infant and Toddler Development-III, a qual possibilita análise do desempenho motor e comparação dos domínios motores axial e apendicular. Foram coletados dados neonatais, familiares e de exposição à creche e pesquisou-se a correlação destes fatores ao desempenho motor. Foi utilizado o teste t pareado para comparar médias e a correlação de Pearson. RESULTADOS: O desempenho motor do grupo esteve, em média, abaixo da referência, com 22,5 por cento das crianças classificadas como suspeitas de atraso nos desempenhos axial e global, contrastando com nenhuma no domínio apendicular. A comparação axial e apendicular apontou diferença significativa, com desempenho axial aquém do apendicular, além de 35 por cento do grupo ter apresentado discrepância significativa entre esses domínios. Não foi encontrada correlação linear entre os domínios motores avaliados e as variáveis neonatais, familiares e de exposição à creche. CONCLUSÕES: O desempenho motor global do grupo esteve abaixo da média de referência, com desempenho motor axial inferior ao apendicular e importante discrepância entre esses. Recomenda-se atenção às habilidades motoras axiais e às oportunidades de exploração que o ambiente em creches pode propiciar, especialmente no decorrer dos dois primeiros anos de vida.

OBJECTIVE: To analyze gross, fine and global motor performance and its correlation with neonatal and familial variables and day care exposure among children between 12-24 months of age attending public day care centers. METHODS: This cross-sectional study evaluated 40 infants (mean age 14.3±2.4 months) attending public day care centers. The Bayley Scales of Infant and Toddler Development-III test was used to assess motor performance and to allow comparison between gross and fine domains of motor development. Neonatal, familial and day care center exposure data were collected and correlated with motor performance. Paired t-tests for mean comparisons and Pearson correlation were used. RESULTS: Motor performance of the studied group was below the average mean. The prevalence of suspected delays in gross and global motor performance was 22.5 percent, in contrast to none in fine motor performance. There was a significant difference between fine and gross motor performance, with the latter displaying lower scores; 35 percent of the group showed significant discrepancies between these areas. No correlation was found between the motor categories, neonatal and familial characteristics, and day care center exposure variables. CONCLUSIONS: The infants' global motor development fell below the average mean, with a delay in gross motor development and a relevant discrepancy between motor domains. This study suggests that attention should be given to gross motor skills and opportunities for exploration the environment in day care centers, especially during the first two years of life.

Influência do diâmetro e da fase folicular sobre a competência in vitro de oócitos obtidos de novilhas da raça Nelore / Influence of diameter and follicular fase on the in vitro competence of oocytes from Nelore heifers

Avaliou-se o efeito do diâmetro e da fase do desenvolvimento folicular sobre a competência de oócitos para a produção in vitro de embriões bovinos. A primeira onda folicular foi sincronizada com progestógeno por nove dias e 24 horas após a sua retirada aplicou-se LH. Os ovários foram recuperados 60h (G-60), 96h (G-96) e 108h (G-108) após a ovulação induzida pelo LH. Os folículos foram dissecados ou aspirados e medidos e os oócitos recuperados e submetidos à maturação, fecundação e cultivo in vitro. Os ovários do G-60 apresentaram mais oócitos viáveis (graus I, II e III) (96,6 por cento). A taxa de clivagem teve efeito significativo sobre o diâmetro folicular, sendo maior nos oócitos oriundos de folículos classe 3 (>7mm). Na taxa de produção de blastocisto observou-se interação diâmetro versus fase de desenvolvimento folicular. A taxa de produção de blastocisto foi maior em oócitos obtidos de folículos com diâmetros <5mm (classe 1) no G-60 (64,5 por cento), de 5-7mm (classe 2) no G-96 (33,3 por cento) e >7mm (classe 3) no G-108 (50 por cento). Conclui-se que o diâmetro e a fase de desenvolvimento folicular influenciam a competência oocitária para o desenvolvimento in vitro. Nos estádios iniciais da onda folicular a produção de blastocisto foi maior em oócitos de folículos pequenos; com o avanço da onda, a produção de blastocistos foi maior em oócitos obtidos de folículos maiores.

The effect of follicular phase and follicle diameter on in vitro production of bovine embryos was evaluated. Follicular wave was synchronized in Nelore heifers with a progestogen for nine days and LH was administered 24 hours after progestogen withdrawal. Ovaries were recovered 60h (G-60), 96 h (G-96), or 108 h (G-108) after LH treatment. Ovarian follicles were dissected or aspirated and measured before oocytes were recovered and submitted to in vitro maturation, fertilization, and culture. The G-60 ovaries presented more viable oocyte (degrees I, II and III) (96.6 percent). Cleavage rate was higher for oocytes from follicles 7mm in diameter (class 3). There was a follicular phase-by-follicle diameter interaction effect on blastocyst production rate. Blastocyst production rates were higher for oocytes from follicles 5mm in diameter (class 1) in the G-60 group (64.5 percent), from follicles 5-7mm (class 2) in the G-96 group (33.3 percent), and from follicles 7mm (class 3) in the G-108 group (50 percent). Both the phase of follicular development and the follicle diameter influenced oocyte competence and ability for development in vitro. At the initial stages of the follicular wave, blastocyst production was higher for oocytes from small follicles. However, as the follicular wave advances, blastocyst production increases for oocytes from larger follicles.

Retardo de crescimento intra-uterino: repercussões no sistema nervoso central e no desenvolvimento de lactentes / Intrauterine growth retardation: repercussions in the central nervous system and in the infant development

Esta revisão da literatura teve como objetivo descrever as repercussões do retardo de crescimento intro-uterino (RCIU) no sistema nervoso central (SNC) e no desenvolvimento de lactentes. Os trabalhos aqui discutidos associam o RCIU a diversas alterações no SNC. No entanto, o tipo e o grau de acometimento dependem do tempo, da duração e gravidade do insulto. Com relação ao desenvolvimento, os lactentes que sofreram RCIU tendem a apresentar déficits neurológicos mínimos, baixo tônus muscular e desempenho motor e mental diminuído quando comparados aos lactentes saudáveis. Algumas pesquisas sugerem, ainda, que tais déficits continuam evidentes durante a infância e na fase adulta Cabe ressaltar, entretanto, que os estudos não são conclusivos. Existe uma grande dificuldade para comparar os trabalhos, devido a heterogeneidade dos grupos investigados. Considerando que um ambiente adequado pode favorecer o desenvolvimento de lactentes de risco, o desafio continua sendo a identificação da forma de atuação do RCIU sobre o SNC e o desenvolvimento de lactentes com vistas à detecção e intervenção precoce.

This review had as objective to describe the repercussions of the intrauterine growth retardation (IUGR) in the central nervous system (CNS) and in the infants' development. The papers here discussed associate IUGR to several alterations in CNS. However, the type and the degree of the injury depend on the time, the duration and the gravity of the insult. Regarding the development, the infants that suffered IUGR tend to present minor neurological deficits, low muscle tone and decreased motor and mental performance, when compared to the healthy infants. Some researches have suggested that such deficits continue evident during the childhood and in the adult phase yet. It is necessary to stress, however, that the studies are not conclusive. A great difficulty exists to compare they papers results, due to the heterogeneity of the investigated groups. Considering that an appropriate environment can favor the development of risk infants, the challenge continues to be the identification of the way IUGR acts on CNS and the infants' development with a view to the early detection and intervention.