bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for Two Concurrent Inhibitory Mechanisms during Response Preparation
Authors: Duque Julie , Lew David , Mazzocchio Riccardo , Olivier Etienne , Ivry Richard B.
Published: March 2010

Inhibitory mechanisms are critically involved in goal-directed behaviors. To gain further insight into how such mechanisms shape motor representations during response preparation, motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) and H-reflexes were recorded from left hand muscles during choice reaction time tasks. The imperative signal, which indicated the required response, was always preceded by a preparatory cue. During the postcue delay period, left MEPs were suppressed when the left hand had been cued for the forthcoming response, suggestive of a form of inhibition specifically directed at selected response representations. H-reflexes were also suppressed on these trials, indicating that the effects of this inhibition extend to spinal circuits. In addition, left MEPs were suppressed when the right hand was cued, but only when left hand movements were a possible response option before the onset of the cue. Notably, left hand H-reflexes were not modulated on these trials, consistent with a cortical locus of inhibition that lowers the activation of task-relevant, but nonselected responses. These results suggest the concurrent operation of two inhibitory mechanisms during response preparation: one decreases the activation of selected responses at the spinal level, helping to control when selected movements should be initiated by preventing their premature release; a second, upstream mechanism helps to determine what response to make during a competitive selection process.
Mirrored Bilateral Slow-Wave Cortical Activity within Local Circuits Revealed by Fast Bihemispheric Voltage-Sensitive Dye Imaging in Anesthetized and Awake Mice
Authors: Mohajerani Majid H. , McVea David A. , Fingas Matthew , Murphy Timothy H.
Published: March 2010

Spontaneous slow-wave oscillations of neuronal membrane potential occur about once every second in the rodent cortex and may serve to shape the efficacy of evoked neuronal responses and consolidate memory during sleep. However, whether these oscillations reflect the entrainment of all cortical regions via propagating waves or whether they exhibit regional and temporal heterogeneity that reflects processing in local cortical circuits is unknown. Using voltage-sensitive dye (VSD) imaging within an adult C57BL/6J mouse cross-midline large craniotomy preparation, we recorded this depolarizing activity across most of both cortical hemispheres simultaneously in both anesthetized and quiet awake animals. Spontaneous oscillations in the VSD signal were highly synchronized between hemispheres, and acallosal I/LnJ mice indicated that synchrony depended on the corpus callosum. In both anesthetized and awake mice (recovered from anesthesia), the oscillations were not necessarily global changes in activity state but were made up of complex local patterns characterized by multiple discrete peaks that were unevenly distributed across cortex. Although the local patterns of depolarizing activity were complex and changed over tens of milliseconds, they were faithfully mirrored in both hemispheres in mice with an intact corpus callosum, to perhaps ensure parallel modification of related circuits in both hemispheres. We conclude that within global rhythms of spontaneous activity are complex events that reflect orchestrated processing within local cortical circuits.
Muller's Ratchet and the Degeneration of theDrosophila mirandaNeo-YChromosome
Authors: Kaiser Vera B , Charlesworth Brian
Published: March 2010

Since its formation about 1.75 million years ago, the Drosophila miranda neo-Y chromosome has undergone a rapid process of degeneration, having lost approximately half of the genes that it originally contained. Using estimates of mutation rates and selection coefficients for loss-of-function mutations, we show that the high rate of accumulation of these mutations can largely be explained by Muller's ratchet, the process of stochastic loss of the least-loaded mutational class from a finite, nonrecombining population. We show that selection at nonsynonymous coding sites can accelerate the process of gene loss and that this effect varies with the number of genes still present on the degenerating neo-Y chromosome.
Nonallelic Gene Conversion in the Genus Drosophila
Authors: Casola Claudio , Ganote Carrie L , Hahn Matthew W
Published: March 2010

Nonallelic gene conversion has been proposed as a major force in homogenizing the sequences of paralogous genes. In this work, we investigate the extent and characteristics of gene conversion among gene families in nine species of the genus Drosophila. We carried out a genome-wide study of 2855 gene families (including 17,742 genes) and determined that conversion events involved 2628 genes. The proportion of converted genes ranged across species from 1 to 9% when paralogs of all ages were included. Although higher levels of gene conversion were found among young gene duplicates, at most 1–2% of the coding sequences of these duplicates were affected by conversion. Using a second approach relying on gene family size changes and gene-tree/species-tree reconciliation methods, we estimate that only 1–15% of gene trees are misled by gene conversion, depending on the lineage considered. Several features of paralogous genes correlate with gene conversion, such as intra-/interchromosomal location, level of nucleotide divergence, and GC content, although we found no definitive evidence for biased substitution patterns. After considering species-specific differences in the age and distance between paralogs, we found a highly significant difference in the amount of gene conversion among species. In particular, members of the melanogaster group showed the lowest proportion of converted genes. Our data therefore suggest underlying differences in the mechanistic basis of gene conversion among species.
Recognition and Absorption of the Water-soluble X-ray Contrast Medium Iodixanol using Molecularly Imprinted Polymers for Biomedical Applications
Authors: Liu Zhan , Bucknall David G. , Allen Mark G.
Published: March 2010

This work presents the study on the recognition and absorption of the water-soluble X-ray contrast medium iodixanol in aqueous solution using synthetic molecularly imprinted polymers (MIPs). A non-covalent imprinting technique was applied to prepare iodixanol-imprinted polymers using 4-vinylpyridine as the functional monomer and ethylene glycol dimethacrylate as the cross-linker. The effects of quantity of iodixanol templates, the crosslink density, and the solvent were studied in terms of the binding capacity and imprint effect of the polymers. UV-vis spectrometric analysis shows that the highest binding capacity achieved is 284 mg iodixanol per gram of dry polymer, which is 8.8 times higher than the binding capacity of the non-imprinted control polymers (NIPs). SEM and BET surface analysis have also been performed to investigate the effect of morphology and porosity on the binding capacities of polymers.
Optimizing Pad Groove Design and Polishing Kinematics for Reduced Shear Force, Low Force Fluctuation and Optimum Removal Rate Attributes of Copper CMP
Authors: Sampurno Yasa , Philipossian Ara , Theng Sian , Nemoto Takenao , Gu Xun , Zhuang Yun , Teramoto Akinobu , Ohmi Tadahiro
Published: March 2010

The effect of polisher kinematics on average and standard deviation of shear force and removal rate in copper CMP is investigated. A ‘delamination factor’ consisting of average shear force, standard deviation of shear force, and required polishing time is defined and calculated based on the summation of normalized values of the above three components. In general, low values of the ‘delamination factor’ are preferred since it is believed that they minimize defects during polishing. In the first part of this study, 200-mm blanket copper wafers are polished at constant platen rotation of 25 RPM and polishing pressure of 1.5 PSI with different wafer rotation rates and slurry flow rates. Results indicate that at the slurry flow rate of 200 ml/min, ‘delamination factor’ is lower by 14 to 54 percent than at 400 ml/min. Increasing wafer rotation rate from 23 to 148 RPM reduces ‘delamination factor’ by approximately 50 percent and improves removal rate within-wafer-non-uniformity by appx. 2X. In the second part of this study, polishing is performed at the optimal slurry flow rate of 200 ml/min and wafer rotation rate of 148 RPM with different polishing pressures and platen rotation rates. Results indicate that ‘delamination factor’ is reduced significantly at the higher ratio of wafer to platen rotation rates.
Understanding Multi Scale Pad Effects in Chemical Mechanical Planarization
Authors: Chandra Abhijit , Bastawros Ashraf. F. , Karra Pavan K.
Published: March 2010

A multi-physics model encompassing chemical dissolution and mechanical abrasion effects in CMP is developed. This augments a previously developed multi-scale model accounting for both pad response and slurry behavior evolution. The augmented model is utilized to predict scratch propensity in a CMP process. The pad response delineates the interplay between the local particle level deformation and the cell level bending of the pad. The slurry agglomerates in the diffusion limited agglomeration (DLA) or reaction limited agglomeration (RLA) regime. Various nano-scale slurry properties significantly influence the spatial and temporal modulation of the material removal rate (MRR) and scratch generation characteristics. The model predictions are first validated against experimental observations. A parametric study is then undertaken. Such physically based models can be utilized to optimize slurry and pad designs to control the depth of generated scratches and their frequency of occurrence per unit area.
Chemical-Mechanical Polishing of Optical Glasses
Authors: Becker Elisabeth , Prange Andreas , Conradt Reinhard
Published: March 2010

This paper presents the Chemical-Mechanical Polishing of optical and fine-optical glasses, which is employed to fulfill the optical requirements for the surfaces of optical lenses. We present the effect of chemical interactions in the polishing process of optical lenses and show how these interactions can be influenced by the additions of certain chemicals. Furthermore, we present a thermodynamic simulation tool, by which these interactions can be modeled. Thus it is possible to understand the chemistry in the suspension and to simulate recent polishing processes in advance, with new additives or with various intrinsic glass ions from different glasses.
Accuracy Improvements in LPC Measurements for CMP Slurries
Authors: Tolla Bruno , Boldridge David
Published: March 2010

We have examined the Large Particle Count (LPC) analytical method to see whether there are opportunities to improve both the accuracy and precision in hope of improving the utility of the LPC measurement. We have identified weaknesses in the current method that limit both its accuracy and its precision, and which can introduce count errors in excess of a factor of 10. We propose modifications to the current method which result in both accuracy and precision improvements. We recommend these improvements as absolutely necessary for any experiments designed to test the correlation between LPC and defectivity.
Novel Ceria-Polymer Composites for Reduced Defects during Oxide CMP
Authors: Coutinho Cecil , Mudhivarthi Subramanya , Kumar Ashok , Gupta Vinay
Published: March 2010

To meet the stringent requirements of device integration and manufacture, surface defects and mechanical stresses that arise during chemical mechanic planarization (CMP) must be reduced. Towards this end, we have synthesized multiple hybrid and composite particles on micron length scales consisting of siloxane co-polymers functionalized with inorganic nanoparticles. These particles can be easily tailored during synthesis, leading to softer or harder abrasion when desired. Upon using these particles for the planarization of silicon oxide wafers, we obtain smooth surfaces with reduced scratches and minimal particle deposition, which is an improvement from conventional abrasive materials like pure silica, ceria and alumina nanoparticle slurries. Tribological characteristics during polishing were examined using a bench top CMP tester to evaluate the in situ co-efficient of friction. Characterization of the hybrid and composite particles has been done using infrared spectroscopy, dynamic light scattering, and electron microscopy. Surface roughness of the wafers was examined using atomic force and optical microscopy while removal rate measurements were conducted using ellipsometry at multiple angles.
Study of Conditioner Abrasives in Chemical Mechanical Planarization
Authors: Manocha Chhavi , Kumar Ashok , Gupta Vinay K.
Published: March 2010

Chemical Mechanical Planarization (CMP) has emerged as the central technology for polishing wafers in the semiconductor manufacturing industry to make integrated multi-level devices. Both chemical and mechanical processes work simultaneously to achieve local and global planarization. Although extensive research has been carried out to understand the various factors affecting the CMP process, many aspects remain unaddressed. One such aspect of CMP is the role of abrasives in the process of conditioning. Abrasives play an important role during conditioning to regenerate the clogged polishing pads. This research is focused on the study of abrasives in the process of conditioning with a focus on the size of abrasives. With diamond being widely used as an abrasive for conditioning the polishing pad, five different sizes of diamonds ranging from 0.25μm to 100μm were selected to condition the commercially available IC 1000 polishing pad. Properties like pad roughness and pad wear were measured to understand the effect of the abrasive size on the pad morphology and pad topography. In-situ ‘coefficient of friction’ was also monitored on the CETR bench top tester. The final impact was seen in the form of surface defects on the polished copper wafers using optical microscopy.
Optimization of Material Removal Efficiency in Low Pressure CMP
Authors: Bozkaya Dinçer , Müftü Sinan
Published: March 2010

In chemical-mechanical polishing (CMP) the material removal efficiency (MRE) can be defined as the fraction of the total pressure distributed on the abrasives, and it depends on the interplay between the direct contact of the pad-to-wafer, and the contact of the abrasives with the wafer. The MRE can be increased by minimizing pad-wafer direct contact, as this is not likely to help material removal, significantly. The objective of this work is to investigate parameters that control MRE. This may be especially important for low-pressure CMP used in the polishing of (ultra-low-k) ULK dielectric materials. The optimization of CMP parameters to maximize the MRE is described by modeling the contact interactions between pad, abrasives and wafer. A relationship for optimal abrasive concentration is presented for the external load values that mark the transition from pure pad-wafer-abrasive contact to mixed contact (combination of pad-wafer-abrasive and pad-wafer contacts) and for given pad porosity and pad surface parameters.
Optical properties and carrier dynamics of ensembles of InP nanowires grown on non-single-crystal platforms
Authors: Onishi Takehiro , Lohn Andrew J. , Kobayashi Nobuhiko P.
Published: March 2010

Optically active InP nanowires were grown on a quartz substrate covered with a layer (100 nm) of hydrogenated amorphous silicon (a-Si:H) by metalorganic chemical vapor deposition (MOCVD), demonstrating that single-crystal semiconductor nanowires can be formed on non-single-crystal surfaces. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, cathodoluminescence (CL), and photoluminescence (PL) were used to characterize the structural and optical properties of the nanowires. The nanowires on a-Si:H grew in random directions with high density. The XRD suggests that nanowires having either hexagonal-close-packed or face-centered cubic lattices co-exist. The Raman spectrum shows peaks associated with transverse optical (TO) and longitudinal optical (LO) branches of InP. The CL intensity does not vary signi?cantly along the growth direction and appears to be originated from the entire structure of the nanowire when probed at various positions. The CL data suggests that recombination is slow enough to allow the carriers to diffuse the complete length of the nanowires (˜2 m in length) before recombining. The PL spectrum suggested the nanowire had a part that contributes to the observed blue shift while the other part had nearly bulk feature in their structure.
A percepção do paciente sobre sua permanência na unidade de terapia intensiva
Authors: Guirardello Edinêis de Brito , Romero-Gabriel Cláudia Adalgisa A. , Pereira Isabel Cristina , Miranda Alba Franzão
Published: March 2010

Este estudo procura identificar a percepção do paciente sobre sua permanência na UTI. A amostra constituiu-se de10 pacientes, submetidos à cirurgia cardíaca e que receberam intervenção psicológica somente após a alta da UTI. Para a coleta e análise dos dados, utilizou-se uma abordagem qualitativa (análise de conteúdo). Os resultados sugerem que o paciente possue uma visão esteriotipada da UTI, vinculada à ideia de sofrimento e morte; o enfermeiro ocupa um importante papel nos momentos de fragilidade, dependência física e emocional; a dor, por seu caráter subjetivo, individual e emocional, é inevitável por estar relacionada aos procedimentos e, muitas vezes, associada ao sofrimento físico.
Hipnose para controle de claustrofobia em exames de ressonância magnética
Authors: Velloso Luiz Guilherme Carneiro , Duprat Maria de Lourdes , Martins Ricardo , Scoppetta Luiz
Published: March 2010

OBJETIVO: Testar a eficácia da hipnose para o controle de claustrofobia em pacientes submetidos a exames de ressonância magnética. MATERIAIS E MÉTODOS: Vinte pacientes claustrofóbicos, com indicação de sedação para ressonância magnética, foram submetidos a hipnose pela técnica de Braid. Os pacientes suscetíveis à hipnose foram encaminhados para realização do exame em estado de transe hipnótico, sem uso de medicamentos para sedação. RESULTADOS: Da amostra estudada, 18 casos (90%) foram suscetíveis à técnica. Dos 16 pacientes sensíveis à hipnose que compareceram para a ressonância magnética, 15 (93,8%) realizaram o exame em transe hipnótico, sem ocorrência de crise de claustrofobia e sem necessitar de medicamentos para sedação. CONCLUSÃO: Hipnose é uma alternativa para a sedação medicamentosa em pacientes claustrofóbicos que necessitam realizar ressonância magnética.
Perda de carga em microtubos e conectores utilizados em microaspersão
Authors: Zitterell Danieli B. , Frizzone José A. , Rettore Neto Osvaldo , Ullmann Mario N.
Published: March 2010

Este trabalho foi desenvolvido com o objetivo de ajustar equações que estimam a perda distribuída de carga em microtubos utilizados em microaspersão e a perda localizada de carga na passagem lateral do fluxo por meio dos conectores na linha lateral. A perda distribuída de carga foi determinada em quatro diâmetros de microtubos com nove a dez repetições para 15 vazões, por meio da aplicação do teorema de Bernoulli. O fator de atrito (f) foi estimado fixando-se o valor de m = 0,25 e calibrando-se o valor do parâmetro c (0,290). A perda localizada de carga foi determinada por diferença entre perda de carga no microtubo mais conector e perda de carga no microtubo. Dois modelos de conectores foram utilizados e caracterizados quanto ao diâmetro interno e dimensões. Uma aproximação matemática foi proposta para calcular a perda localizada de carga com base em coeficiente de carga cinética do conector (K'), que leva em consideração as dimensões do conector e do microtubo e independência das forças viscosas para Re > 5.000. As variações de vazão e de pressão entre os emissores situados nos extremos da linha lateral mostraram-se sensíveis à perda de carga na passagem lateral pelo conector mais a perda de carga no microtubo.
Características físico-químicas e microbiológicas de morango minimamente processado
Authors: Ponce Adriana dos Reis , Bastiani Maria Inês Dantas , Minim Valéria Paula , Vanetti Maria Cristina Dantas
Published: March 2010

O presente trabalho teve como objetivo avaliar as alterações físico-químicas e microbiológicas de morangos submetidos ao processamento mínimo. Foram avaliados os efeitos da lavagem com cloreto de cálcio ou polietilenoglicol na microbiota contaminante e na textura dos morangos e da sanificação com ozônio gasoso ou clorado orgânico. Análises de textura, cor, perda de massa e microbiota contaminante foram feitas durante o armazenamento a 5 °C por 12 dias em embalagens envoltas com uma a quatro camadas de filme de cloreto de polivinil (PVC). A adição de até 1,5% de cloreto de cálcio ou de 0,5% de polietilenoglicol na água de lavagem não garantiu a manutenção da textura do morango ao final do período de armazenamento. A ozonização dos morangos por 60 minutos foi mais efetiva para reduzir (p < 0,05) a contagem de mesófilos aeróbios, fungos e leveduras e coliformes do que a ozonização por 30 minutos ou a imersão em solução de clorado orgânico. Os morangos armazenados em embalagens recobertas com três camadas de filme PVC apresentaram aumento na textura e na intensidade de escurecimento e redução na microbiota contaminante. Os principais fungos isolados de morangos minimamente processados durante o armazenamento pertenciam ao gênero Fusarium e à espécie Cladosporium cladosporioides.
Aplicação do modelo hipercubo para análise de um sistema médico-emergencial em rodovia
Authors: Mendonça Fernando César , Morabito Reinaldo
Published: March 2010

Em um sistema médico-emergencial, o nível de serviço é fundamental, pois a qualidade de atendimento poderá ser a diferença entre a vida e a morte do usuário. Além da qualidade do atendimento, um dos componentes mais importantes do nível de serviço é o tempo médio de resposta a uma chamada emergencial. Entretanto, adquirir equipamentos e/ou treinamentos para a equipe, para reduzir este tempo de resposta, incorre em custos e investimentos adicionais. Nesta situação, aparece um importante trade-off entre o nível de serviço e o investimento no sistema. Para auxiliar a análise deste trade-off, há um modelo conhecido da literatura chamado hipercubo, que é baseado em teoria de filas espacialmente distribuídas. Neste artigo, adaptamos e aplicamos o modelo hipercubo para analisar os Anjos do Asfalto, um sistema médico-emergencial localizado ao longo da Rodovia Presidente Dutra entre as cidades do Rio de Janeiro e São Paulo. Os resultados mostraram que o modelo hipercubo pode ser uma ferramenta efetiva de apoio às decisões estratégicas e operacionais em sistemas emergenciais em rodovias.
Sugarcane silage production treated with additives at different times post burning
Authors: Roth Anna Paula de Toledo Piza , Reis Ricardo Andrade , Siqueira Gustavo Rezende , Roth Marcella de Toledo Piza , Resende Flávio Dutra de , Monteiro Rafael Rodrigues
Published: March 2010

This trial aimed to evaluate the effects of the time post-burning, and additives on fermentative characteristics, losses and chemical composition on the sugar cane silage. The sugar cane variety IAC 86-2480 was ensiled on the 1, 4, 7, 10 and 14 days after burning. The additives evaluated were: control (Cont.), Lactobacillus buchneri (LB), Calcium oxide micro pulverized (CO), and Lactobacillus buchneri (LB) plus Calcium oxide micro pulverized (LB + CO). The yeast population was determined before ensiled. After 56 days of the fermentation period the silos were opening to take samplings. The experimental design was a completely randomized design, in a factorial scheme (additive and burning time) with seven treatments and four replications. The sugar cane was recontaminated with yeast, the populations increased from 5.04 to 6.48 log cfu/g of forage. Dry matter content decreased after fermentation period in average 7.6 units, compared to the sugar cane forage before ensilage. Control and LB silage showed lowest dry matter recovery (DMR), 613 g/kg and 631 g/kg, respectively, compared to the Cal and LB + Cal, 807 g/kg and 832 g/kg. This fact probably was associated to the calcium oxide control on the yeast populations. In relation to the time post-burning, the greatest changes were observed in the gas production and DMR. Gas production were higher in the first days post-burning and decreased in response to the prolongation time post-burning. The time post-burning alters the nutritive value of the fresh sugarcane and its silage and also the size of the losses from the ensilage process.
Queima e aditivos químicos e bacterianos na ensilagem de cana-de-açúcar
Authors: Siqueira Gustavo Rezende , Reis Ricardo Andrade , Schocken-Iturrino Ruben Pablo , Pires Aureliano José Vieira , Bernardes Thiago Fernandes , Roth Marcella de Toledo Piza
Published: March 2010

Objetivou-se avaliar o efeito da queima e do uso de aditivos (ureia, benzoato de sódio, hidróxido de sódio (NaOH), Propionibacterium acidipropionici + Lactobacillus plantarum e Lactobacillus buchneri) na ensilagem de cana-de-açúcar. Utilizou-se o delineamento inteiramente casualizado, em esquema fatorial 2 (cana-de-açúcar crua e queimada) × 6 (cinco aditivos mais o grupo controle) com três repetições. Determinaram-se as perdas durante o processo fermentativo nas formas de gases e de efluentes e a recuperação de matéria seca (MS). Maior recuperação de MS foi observada nas silagens de cana-de-açúcar queimada (77,3%) em relação às silagens de cana crua (73,1%). As recuperações de MS observadas nas silagens tratadas com NaOH ou L. buchneri foram de 84%, enquanto das silagens controle, 69%. No período após abertura, uma variável importante é a inibição da elevação do pH, nesse caso, medida pela variação do pH. Destacam-se como inibidores da variação do pH o benzoato de sódio e o L. buchneri, que promoveram variação do pH de 0,05 e 0,18 unidade de pH, respectivamente. A ensilagem da cana-de-açúcar sem aditivos, crua ou queimada, é uma estratégia que resulta em grandes perdas quantitativas, que podem ser evitadas pelo uso de aditivos. Entre os aditivos avaliados, o L. buchneri é o que atua de forma mais satisfatória nas fases de fermentação e pós-abertura de silagens de cana-de-açúcar crua ou queimada.
Níveis de suplemento à base de fubá de milho para novilhos Nelore terminados a pasto na seca: desempenho, características de carcaça e avaliação do pasto
Authors: Baroni Carlos Eduardo Sverzut , Lana Rogério de Paula , Mancio Antonio Bento , Queiroz Augusto César de , Leão Maria Ignez , Sverzut Cláudio Bianor
Published: March 2010

Objetivou-se com este trabalho avaliar a disponibilidade dos componentes da pastagem, o ganho de peso e as características de carcaça de novilhos Nelore recebendo suplemento na fase de terminação durante o período seco. O experimento foi realizado em pastagem de capim-braquiária (Brachiaria brizantha, cv. Marandu), em seis piquetes de 9 hectares. Utilizaram-se 48 novilhos com 30 meses e peso inicial de 412 ± 16 kg, distribuídos ao acaso em seis lotes de oito animais. Cada lote foi alojado em um piquete e pesado no início e a cada 21 dias, durante 84 dias. Os suplementos foram fornecidos nos níveis de 0,25; 0,5; 1,0; 2,0; e 4,0 kg/animal.dia em comparação a um suplemento controle, com apenas mistura mineral. Os suplementos, à exceção do controle, apresentaram níveis variáveis de proteína bruta (87,4 a 25,0% da matéria seca) e 25:25:50, 15:15:70, 10:10:80, 5:5:90 e 2,5:2,5:95 para 0,25; 0,5; 1,0; 2,0; e 4,0 kg/animal.dia, respectivamente, uma vez que a ureia foi usada como controladora do consumo de suplemento. O delineamento foi inteiramente casualizado e os níveis de suplementação foram avaliados por análise de regressão. A proporção de colmo e folha seca aumentou no decorrer dos períodos experimentais, caracterizando déficit hídrico da estação seca. Houve efeito linear crescente dos níveis de suplemento sobre o peso vivo final, o ganho de peso médio diário e o ganho médio por período, tanto em relação ao consumo de suplemento quanto em relação ao consumo de proteína bruta e nutrientes digestíveis totais. Os níveis de suplemento têm efeito linear crescente sobre o peso de carcaça e a espessura de gordura subcutânea e efeito quadrático sobre o rendimento de carcaça.
Spatial and temporal variability of canopy cover and understory light in a Cerrado of Southern Brazil
Authors: Lemos-Filho JP. , Barros CFA. , Dantas GPM. , Dias LG. , Mendes RS.
Published: March 2010

Canopy cover has significant effects on the understory environment, including upon light availability for seedling growth. The aim of the present study was to verify spatial heterogeneity and seasonal changes in the canopy cover of a dense Cerrado area, and their relationship to understory photosynthetic active radiation availability. Leaf area index (LAI) values in the rainy season varied from 0.9 to 4.83, with 40% of the values ranging from 4.0 to 5.0, while in the dry season LAI varied from 0.74 to 3.3, with 53% of the values oscilating from 2.0 to 3.0. Understory light (Qi ) and the Lambert-Beer ratio (Qi/Qo) were taken around noon on sunny days (between 11:00 AM and 1:00 PM). They were also statistically different (p < 0.01) between the dry and wet seasons, with 72% of sampled points in the rainy season presenting photosynthetic photon flux density (PPFD) values lower than 250 μmol.m-2/s around noon, whereas in the dry season, most PPFD values varied from 1500 to 1817 μmol.m-2/s , thus providing high light availability for understory plants. In most of the studied sites, understory plants did not even receive enough light for 50% of their photosynthetic capacity in the wet season. In contrast during the dry season, Qi/Qo values of 0.8 to 1.0 were observed in more than 50% of the points, thereby allowing for photosynthetic light saturation. Thus, light variability around noon was higher during the dry season than in the wet season, its heterogeneity being related to spatial complexity in the canopy cover.
Group size and composition of Guiana dolphins (Sotalia guianensis) (Van Bénèden, 1864) in the Paranaguá Estuarine Complex, Brazil
Authors: Santos MCO. , Oshima JEF. , Pacífico ES. , Silva E.
Published: March 2010

The aim of the present study was to describe the characteristics of Guiana dolphins (S. guianensis) group size and composition in the Paranaguá Estuarine Complex (25° 15' -25° 36' S and 48° 02'-48° 45' W), Paraná State, as well as to verify the existence of relationships between a given environmental variable (water depth, salinity, transparency and temperature) and group size. An area of around 124 km² was surveyed by boat from April 2006 to February 2008 in the following subsets of the estuary: Canal do Superagui (~28 km²), Pinheiros bay (~34 km²), part of Laranjeiras bay, which included the Guaraqueçaba sub-estuary (~38 km²), and part of the Mixture Section of the Paranaguá Estuarine Complex (~24 km²). In 45 survey days, a total of 147 hours were spent observing 286 groups of S. guianensis. Groups varied from two individuals to aggregations of up to 90 individuals (mean ± SD: 11.5 ± 14.4 individuals). Solitary individuals were seen only on five occasions (1.7% of all observations). Groups with calves (n = 247) represented 86.4% overall and were more common in all sub-areas when compared to groups without calves. Groups without calves were found in all sub-areas and were usually smaller and composed of up to 12 individuals. A usual group composition of 70% of adults and 30% of calves was observed considering all sub-areas and seasons. No correlations were found between group size and water temperature (Spearman's rank test, r = 0.0059, p = 0.9338), transparency (Spearman's rank test, r = 0.0597, p = 0.9333), depth (Spearman's rank test, r = 0.1421, p = 0.4698), and salinity (Spearman's rank test, r = -0.1938, p = 0.0665). While Guiana dolphin groups were seen in the entire surveyed area, group size varied significantly among the three main surveyed sub-areas (Kruskal Wallis, H2,196 = 29.85, p = 0.0000). Groups were larger in Laranjeiras bay and smaller in Canal do Superagui. The physical environment, risk of predation, seasonal distribution and abundance of prey are the main possible factors driving larger groups in inner and protected waters.
Germination response of Hylocereus setaceus (Salm-Dyck ex DC: ) Ralf Bauer (Cactaceae) seeds to temperature and reduced water potentials
Authors: Simão E. , Takaki M. , Cardoso VJM.
Published: March 2010

The germination response of Hylocereus setaceus seeds to isothermic incubation at different water potentials was analysed by using the thermal time and hydrotime models, aiming to describe some germination parameters of the population and to test the validity of the models to describe the response of the seeds to temperature and water potential. Hylocereus setaceus seeds germinated relatively well in a wide range of temperatures and the germination was rate limited from 11 to 20 °C interval and beyond 30 °C until 40 °C, in which the germination rate respectively shifts positively and negatively with temperature. The minimum or base temperature (Tb) for the germination of H. setaceus was 7 °C, and the ceiling temperature varied nearly from 43.5 to 59 °C depending on the percent fraction, with median set on 49.8 °C. The number of degrees day necessary for 50% of the seeds to germinate in the infra-optimum temperature range was 39.3 °C day, whereas at the supra-optimum interval the value of θ = 77 was assumed to be constant throughout. Germination was sensitive to decreasing values of ψ in the medium, and both the germinability and the germination rate shift negatively with the reduction of ψ, but the rate of reduction changed with temperature. The values of base water potential (ψb) shift to zero with increasing temperatures and such variation reflects in the relatively greater effect of low ψ on germination in supra optimum range of T. In general, the model described better the germination time courses at lower than at higher water potentials. The analysis also suggest that Tb may not be independent of ψ and that ψb(g) may change as a function of temperature at the infra-otimum temperature range.
Water-balance response of Rhinella arenarum (Hensel, 1867) tadpoles to graduated increase in environmental osmolarity
Authors: Ferrari L. , de la Torre FR. , Salibián A.
Published: March 2010

The water balance and the upper limit of osmotic tolerance of premetamorphic Rhinella arenarum larvae (Gosner's stage 26) was evaluated after semistatic incubation in electrolyte (NaCl) and non-electrolyte (mannitol) media following a protocol of progressively increased osmotic pressure. Wet and dry weights were measured to calculate the water content as a derived variable indicative of the hydric balance. Statistical analysis was performed using univariate and integrated multivariate analysis. Tadpoles survived in electrolyte and non-electrolyte solutions up to 200 mOsm. The discriminant function was the best tool to describe the responses of the animals to external environmental stress under experimental conditions. The results were compared with those obtained in previous studies using a protocol of acute exposure to the same media used in this study. It was concluded that a) multivariate analysis is an appropriate approach to describe the responses of tadpoles to changes in the environmental physicochemical parameters, and b) progressive and acute acclimation to the experimental solutions induced similar responses.
N-cadherin increases after androgen deprivation and is associated with metastasis in prostate cancer
Authors: Jennbacken Karin , Tešan Tajana , Wang Wanzhong , Gustavsson Heléne , Damber Jan-Erik , Welén Karin
Published: March 2010

Androgen-deprivation therapy (ADT) is the standard treatment for metastatic prostate cancer. One factor that has been implicated in the metastatic process is the cell adhesion molecule N-cadherin. In this study, we investigated if the expression of N-cadherin was influenced by androgen deprivation and was associated with metastasis in prostate cancer. The effect of androgen deprivation on N-cadherin expression was initially studied in androgen-dependent (AD) LNCaP and androgen-independent (AI) LNCaP-19 and PC-3 prostate cancer cell lines. Expression of N-cadherin increased in the absence of androgens in AI LNCaP-19 primary tumors and metastases and also in vitro, but not in AI PC-3 tumors, indicating a possible involvement of the androgen receptor in the regulation of N-cadherin. N-cadherin was absent in AD LNCaP tumors. No clear associations between N-cadherin and factors related with epithelial–mesenchymal transition or neuroendocrine differentiation could be established. In addition, N-cadherin was evaluated by immunohistochemistry in human prostate tumors. Expression of N-cadherin was more frequently found in tumors from patients treated with ADT than in tumors from patients with no prior hormonal treatment. N-cadherin expression was also associated with metastasis and Gleason score. Furthermore, increased N-cadherin was detected in prostate cancer biopsies already 3 months after initiation of ADT when tumors were in a regressed state. In summary the results indicate that androgen deprivation induces N-cadherin in prostate tumors. Moreover, N-cadherin was increased in castration-resistant tumors in patients with established metastases. This might indicate that castration induces molecular alterations in the tumor cells, resulting in a more invasive and metastatic phenotype.
Finite-element software for conceptual design
Authors: Lindemann J. , Sandberg G. , Damkilde L.
Published: March 2010

Using finite-element analysis in conceptual design and teaching has quite different software requirements to that in engineering and research. In teaching and conceptual design the focus is on speed, interactivity and ease of use, whereas accuracy and precision are needed in engineering and research. Forcepad is an effort to provide a conceptual design and teaching tool in a finite-element software package. Forcepad is a two-dimensional finite-element application based on the same conceptual model as image editing applications such as Adobe Photoshop or Microsoft Paint. Instead of using geometric modelling with polygons, curves and lines, modelling is accomplished by ‘painting' with pixels with varying stiffness properties. This makes the learning curve for finite-element analysis much shallower and also makes it available for a much wider audience. The software has been used with great success in teaching as well as in conceptual design environments such as architecture, industrial design and engineering. The addition of an optimisation algorithm and tablet PC support makes the software even more interesting as a tool for conceptual design.
Modelling heat exchange between RCC dam and reservoir
Authors: Bayagoob K. H. , Noorzaei J. , Jaafar M. S. , Thanoon W. A. , Abdulrazeg A. A.
Published: March 2010

Temperature control plays an important role in the design and construction of roller-compacted concrete (RCC) dams. Hydration of cement and climatic changes on the convective boundaries are the two main heat sources of the temperature rise in RCC dams. Therefore, the effects of these two factors have to be determined accurately in order to reduce the risk of thermally induced cracking in these dams. Simplified approaches are usually adopted to approximate the temperature changes on the upstream dam side after the dam reservoir is filled. These simplified approaches are usually based on long-term observations of similar reservoirs. However, it is practically hard to generalise the conditions of these reservoirs with respect to the reservoir under consideration. In this work, the finite-element method has been used to simulate the heat exchange between the RCC dam body and the reservoir water taking into account the reservoir operation. A realistic isothermal profile has been obtained that has been used to determine the cracking probability of the RCC dam body.
Modelling THMs in water treatment and distribution systems
Authors: Brown D. , West J. R. , Courtis B. J. , Bridgeman J.
Published: March 2010

The formation of potentially harmful trihalomethanes (THM) when using chlorine as a disinfectant in potable water supplies has led to tighter regulatory controls and hence a need for better models for THM management. The prediction of THM concentration is difficult due to the complex and changing hydrodynamic and chemical regimes found in water treatment works and distribution systems. A simple and cost-effective model is described to model chlorine decay and total THM concentration through water treatment works and within distribution systems. With knowledge of the bulk chlorine decay characteristics and the THM productivity of the water, this model offers a simple and straightforward tool which can be readily applied to water treatment works and distribution systems alike to provide an initial assessment of the risks of total THM formation at different sites, and to identify sites and systems at risk of compliance failure.
Artificial intelligence model for water resources management
Authors: Tang H. W. , Lei Y. , Lin B. , Zhou Y. L. , Gu Z. H.
Published: March 2010

The channel network in Pudong New District, Shanghai, is very complex owing to the large area of its basin, its numerous sluice gates, complex influencing factors and some other management issues involving water delivery, flood prevention, floodwater drainage, navigation and saltwater intrusion. It is generally difficult to achieve efficient water resources management merely through manually operating the sluice gates. Therefore, an artificial intelligence modelling system for managing the water resources in the channel network of Pudong New District has been developed by combining hydrodynamic simulation with an artificial intelligence technique. The artificial neural network model is used to develop sluice gate operation procedures according to the water levels in both the outer and inner rivers. The hydrodynamic model is used to simulate the flow discharges and water levels based on the sluice gate operation procedures. This modelling system has been applied successfully to the water resources management of the Pudong channel network. The results indicate that the modelling system satisfactorily meets the demands for sluice gate operation and water resources optimisation management of the channel network and thus provides decision-making support for integrated management of water resources in this inland channel network.
Positive surge in trapezoidal and circular channels
Authors: Mitchell S. B.
Published: March 2010

A series of algorithms is proposed for calculating the flow depth ratio and surge wave velocity for positive surge waves in open channels of rectangular and trapezoidal sections and for circular sections running part full. These algorithms make use of the standard formulations for the solution of problems of this kind and propose some iterative protocols (Newton–Raphson, numerical interpolation) for finding the desired result. The algorithms may be incorporated into a spreadsheet or a similar software package for use by hydraulic design engineers. Some results for a few selected cases are presented and show a dependence of depth ratio and surge wave velocity on flow ratio and on Froude number prior to the arrival of the surge wave. There is also a dependence on flow and channel scale in all cases, except that for rectangular flows; the depth ratio is independent of scale for the conditions investigated. There is also evidence of a minimum surge wave velocity for surge waves moving downstream at a specific Froude number for rectangular and circular sections, although not for trapezoidal sections. The algorithms generally give good agreement with the literature, although it is noted that in real situations an undular wave front is generally observed, and that most of the experiments cited have hitherto only been carried out in rectangular channels. Given the effect of friction on moderating the passage of the surge wave, the idealised assumption of a frictionless channel is clearly of importance.
Choke-free flow in circular and ovoidal channels
Authors: Vatankhah A. R. , Bijankhan M.
Published: March 2010

A comprehensive solution for circular and ovoidal channel sections is obtained under the condition of choke-free flow owing to a gradual and smooth rise in bed elevation. Generally, two practical cases of channel transition are considered: (a) rising bed elevation caused by a change in the position of the channel centreline; and (b) rising bed elevation caused by a decrease in the channel diameter. Considering the critical flow occurring downstream of the transition zone, the energy equation is solved with the aid of a numerical technique to determine the explicit equations for the maximum allowable bed rise under a given approaching regime. Moreover, to determine the limits of upstream flow depths (the choke-free regions) from the information on upstream channel geometry, rise in bed elevation and discharge, suitable graphical solutions are presented using dimensionless specific energy equations. These graphs can be utilised to choose the operating ranges of upstream flow depths for choke-free flow in both subcritical and supercritical upstream flow conditions. Since the downstream critical depth is required to determine the upstream operating range, the direct solutions for critical depths in circular and ovoidal channels are also presented. Finally, energy loss in the transition zone is considered by applying it in the proposed equations.
Enhancement of carboxylic acid degradation with sulfate radical generated by persulfate activation
Authors: Criquet J. , Nebout P. , Karpel Vel Leitner N.
Published: March 2010

The aim of this work was to investigate the generation of sulfate radical for the removal of two carboxylic acids in aqueous solution: acetic and citric acids. From photochemical and radiolytic processes, kinetics of the degradation of these two carboxylic acids was studied as a function of the pH of the solution. It was shown that the maximum of acetic acid degradation occurred at pH 5. Above this pH, competitive reactions with the carbon mineralized inhibit the reaction of with the solute. In the case of citric acid, pH has only a little effect on the kinetic of citric acid degradation. The determination of mineralization yields shows several differences depending on carboxylic acids and pH. The degradation of both carboxylic acids was also studied in the radiolysis process whether with or without persulfate addition. A comparison of the processes of sulfate radical production is presented.
Ceramic membrane ultrafiltration of natural surface water with ultrasound enhanced backwashing
Authors: Boley A. , Narasimhan K. , Kieninger M. , Müller W.-R.
Published: March 2010

Ultrafiltration membrane cleaning with ultrasound enhanced backwashing was investigated with two ceramic membrane systems in parallel. One of them was subjected to ultrasound during backwashing, the other acted as a reference system. The feed water was directly taken from a creek with a sedimentation process as only pre-treatment. The cleaning performance was improved with ultrasound but after 3 weeks of operation damages occurred on the membranes. These effects were studied with online measurements of flux, trans-membrane-pressure and temperature, but also with integrity tests, turbidity measurements and visual examination.