bluuebunny/crossref_metadata_2025 huggingface dataset:
Partícula em um poço de potencial infinito e o método variacional de Monte Carlo
Authors: Canabrava Rodrigo , Vitiello Silvio A.
Published: May 2009

Neste trabalho, apresentamos o método variacional de Monte Carlo, aplicado a um sistema de uma partícula confinada em um poço de potencial infinito. A amostragem da densidade de probabilidade é feita utilizando-se o algoritmo de Metropolis. O objetivo do trabalho é apresentar de forma didática o método e sua implementação em computadores.
Supresión de modos de vibración acústicos con un resonador Helmholtz
Authors: Guiguet Andrés , Welti Reinaldo
Published: May 2009

La inserción de un Resonador Helmholtz (RH) en las paredes laterales de un tubo, con ondas estacionarias en su interior, logra suprimir uno o más de sus modos resonantes si se elige adecuadamente la frecuencia del resonador. El RH puede actuar también como filtro de ondas propagantes.' En este caso, el RH atenua las ondas en un rango de frecuencia muy selectivo. En la mayoría de los textos de acústica, solamente se desarrolla la teoría que explica el filtrado de ondas propagantes. Sin embargo, en los laboratorios de física basica, donde se dispone solamente de tubos de Kundt de pequeña longitud, no es simple realizar un arreglo experimental que asegure la presencia de ondas propagantes puras en su interior. La falta de una teoría para ondas estacionarias y las dificultades experimentales que señalamos han producido algunas confusiones en trabajos que tratan sobre el tema. En este artículo se presenta un modelo teórico que describe satisfactoriamente el comportamiento del RH cuando funciona como filtro de ondas estacionarias y se marcan las diferencias con la situación en que opera como filtro de ondas propagantes.
Sobre as causas naturais que formam a base empírica do fenômeno dos turbilhões nas cosmogonias: dos Pré-Socráticos a René Descartes
Authors: Baptista José Plínio , Ferracioli Laércio
Published: May 2009

Neste trabalho é apresentado um possível fundamento empírico para as teorias dos turbilhões que figuram em praticamente todas as teorias cosmogônicas dos pré-socráticos e mesmo presentes nas teorias de pensadores modernos como René Descartes e C. Huyghens.
Uma bifurcação sela-centro em campos Hamiltonianos planares
Authors: Mello Luis Fernando , Santos Grasiele Batista dos
Published: May 2009

Neste trabalho estudamos um modelo de bifurcação sela-centro encontrado em uma família a um parâmetro de campos de vetores planares Hamiltonianos. Este estudo é feito através da análise da mudança qualitativa dos retratos de fase destes campos. Neste cenário bastante particular, o conhecimento da família a um parâmetro das funções Hamiltonianas é suficiente para a determinação dos retratos de fase dos campos envolvidos.
A física clássica de cabeça para baixo: como Einstein descobriu a teoria da relatividade especial
Authors: Renn Jürgen
Published: May 2009

Albert Einstein por duas vezes alterou de maneira profunda nossos conceitos de espaço e tempo com a sua teoria da relatividade: primeiro no âmbito da teoria especial de 1905 e depois com a teoria geral de 1915. Como foi o jovem Albert Einstein capaz de dar início a esta revolução?
Para o ensino do átomo de Bohr no nível médio
Authors: Peduzzi Luiz O.Q. , Basso Andreza C.
Published: May 2009

Este artigo apresenta o perfil geral de um texto sobre o átomo de Bohr voltado para o professor do Ensino Médio, bem como os resultados de sua avaliação por uma amostra de professores que atuam nesse nível de ensino. Conferindo uma abordagem didática à teoria de Bohr com base no estudo de Lakatos: ''Bohr: um programa de pesquisa que progride sobre fundamentos inconsistentes'', o texto apresenta-se como uma alternativa não empirista a este tema, contrastando com a orientação epistemológica tradicional, presente em livros didáticos.
Estudo do movimento de um corpo sob ação de força viscosa usando uma porção de xampu, régua e relógio
Authors: Neves Ubaldo Martins das
Published: May 2009

Experimentos didáticos sobre movimento uniforme usualmente requerem equipamentos e montagens de custos relativamente altos. Esse fato é um obstáculo para alunos e professores de escolas que não possuam um laboratório de ensino bem equipado. Nesse artigo, descrevemos um experimento alternativo para o estudo do movimento de um corpo num meio viscoso. Devido a sua simplicidade, o experimento pode ser realizado até mesmo em casa, sem muita dificuldade. Os materiais compreendem uma porção de xampu, régua e um relógio digital. O experimento consiste na medida direta das velocidades com que as bolhas de ar sobem dentro do xampu. Demonstramos que uma dependência exponencial para a for ca viscosa com a velocidade produz resultados que concordam com as medidas experimentais.
Polinômio dos quadrados mínimos condicionado
Authors: Dotto Oclide J. , Dornelles Filho Adalberto A.
Published: May 2009

O ajustamento polinomial a dados experimentais pelo método de quadrados mínimos é muito usado, e aqui estudamos a introdução de uma simples modificação, que, em certos casos, é mais adequada, isto é, condicionamos o polinômio a conter um dado ponto. Incluímos uma implementação do correspondente algoritmo em MATLAB.
Extensões auto-adjuntas de operadores em mecânica quântica
Authors: Filgueiras C. , Moraes Fernando
Published: May 2009

O problema das extensões auto-adjuntas de operadores em mecânica quântica, um assunto normalmente não apresentado em livros-texto, é brevemente discutido neste trabalho.
Teorema de Van der Pauw
Authors: Robert Renê , Berleze Sergio M.
Published: May 2009

O objetivo deste trabalho é mostrar o uso do teorema de van der Pauw e sua dedução. Este teorema permite determinar a condutividade elétrica de placas planas com perímetros arbitrários, espessura uniforme e quatro contatos sobre a periferia.
A importância da física nas quatro primeiras séries do ensino fundamental
Authors: Schroeder Carlos
Published: May 2009

Este artigo sugere que a importância das aulas de física desde as primeiras séries do ensino fundamental está muito mais no auxílio ao desenvolvimento da auto-estima e da capacidade de aprender-a-aprender das crianças do que em aspectos utilitários, tais como preparar os estudantes para os conteúdos do ensino médio. Alguns exemplos de atividades que podem ser propostas a crianças com idades entre sete e dez anos, nas quais a possibilidade de explorar a física pode ser útil para o desenvolvimento da capacidade de aprender-a-aprender, também são apresentados, acompanhados de uma discussão dos resultados observados.
Modelagem computacional em problemas de eletrostática: efeito de campos de borda em capacitores cilíndricos finitos
Authors: Xavier Jr. Ademir L.
Published: May 2009

Nesse trabalho apresenta-se um estudo de soluções numéricas para o problema de capacitores cilíndricos finitos em eletrostática, a partir da integração da equação de Poisson utilizando um esquema de diferenças finitas. Soluções são obtidas pelo método da relaxação sucessiva. O problema ilustra o tratamento numérico na obtenção de soluções eletrostáticas em problemas diferentes dos encontrados em livros-texto. Para o problema em questão, diversas quantidades de interesse (distribuição de cargas, capacitância, energia do campo eletrostático, força) podem ser comparadas com o caso analítico infinito.
Duas nuvens ainda fazem sombra na reputação de Lorde Kelvin
Authors: Schulz Peter A.
Published: May 2009

Lorde Kelvin é considerado um dos mais importantes físicos do século XIX. Talento multifacetado e homem público é autor de aforismos famosos, mas muitas frases a ele atribuídas não passam de lendas urbanas. Uma das mais famosas é a de "existem apenas duas nuvenzinhas no céu da física", e suas variantes, aludindo à crença de completude da física no início do século passado. As "duas nuvenzinhas" nada mais são do que a teoria da relatividade e a mecânica quântica, os dois pilares da física moderna. Ao contrário do que muitos propagam, Lorde Kelvin na verdade parecia estar bem ciente do impasse da física clássica na época e deixou para os seus sucessores uma indicação clara de que rumos deveriam ser seguidos.
A natureza da ciência por meio do estudo de episódios históricos: o caso da popularização da óptica newtoniana
Authors: Silva Cibelle Celestino , Moura Breno Arsioli
Published: May 2009

Apesar das dificuldades em abordar a natureza da ciência em sala de aula, há um entendimento geral da necessidade de incorporar nos currículos noções sobre como ocorre a construção do conhecimento científico. Conhecer a história do desenvolvimento e do processo de aceitação de teorias científicas pode ajudar os professores a incluir discussões sobre a natureza da ciência no ensino de ciências. Este trabalho apresenta uma análise da aceitação e propagação das teorias sobre luz e cores de Newton ao longo do século XVIII. Apontaremos para alguns aspectos da natureza da ciência que podem ser evidenciados pelo estudo desse episódio histórico.
Sum of squares in discrete physical spaces
Authors: De Luca R.
Published: May 2009

Discretization of three-dimensional physical spaces can induce, on observable physical quantities, effects which are not present in the continuum. Consider, as an example, the problem of the radiation spectrum of a blackbody, studied in introductory courses in quantum mechanics. One sees that the Rayleigh assumption of continuous and uniform frequency distribution of standing waves inside a cubic cavity with perfectly reflecting inner walls can be validated by a heuristic type of reasoning. However, by means of number theory, one sees that there might exist frequencies for which it is not possible to have standing waves inside the cavity. Nevertheless, within the same context, one can argue that a more general criterion can be adopted to validate the hypothesis of continuity of the observables which are expressed as the square root of the sum of three integers of a threedimensional space On x n y n z.
External Morphology and Development of Immature Stages of Diadegma semiclausum (Hymenoptera: Ichneumonidae), an Important Endoparasitoid of Plutella xylostella (Lepidoptera: Plutellidae)
Authors: Huang Fang , Shi Min , Chen Xue-Xin , Ye Gong-Yin , He Jun-Hua
Published: May 2009

Diadegma semiclausum (Hellén) (Hymenoptera: Ichneumonidae) is one of the most important biological control agents of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae). Each immature stage of D. semiclausum was studied by dissecting parasitized hosts in the laboratory at 22 ± 1°C and 70–75% RH. Results show that the egg is hymenopteriform, lacking appendages. The larvae seem to be hypermetamorphic, with four instars. The pupal period has two distinct phases: 1) phase I, larval-like with remarkable groups of urate cells; and 2) phase II, exarate pupal appearance with a pigmentation sequence of eyes, ocelli, mandibles, thorax, abdomen, and antennae. All stages and sequences are illustrated with detailed photomicrographs.
In-Field and Soil-Related Factors that Affect the Presence and Prediction of Glyphosate-Resistant Horseweed (Conyza canadensis) Populations Collected from Indiana Soybean Fields
Authors: Davis Vince M. , Gibson Kevin D. , Mock Valerie A. , Johnson William G.
Published: May 2009

Glyphosate-resistant (GR) crops have been rapidly adopted in the United States and the evolution of GR weeds throughout the world has also been on the rise. With experience, weed scientists and crop advisers develop “intuition” on the basis of field history and current in-field conditions for predicting whether escaped weed biotypes may be herbicide resistant. However, there are no previous reports on the association of in-field crop management factors with the prediction of herbicide resistance. By using in-field survey data, we tested the accuracy of predicting glyphosate resistance in late-season horseweed escapes. We hypothesized that glyphosate resistance in late-season horseweed populations found in soybean fields could be predicted using in-field knowledge of crop residues and the appearance and distribution of weeds in the field. Field survey data were collected to determine the distribution and frequency of GR horseweed populations in Indiana soybean fields during September and October of 2003, 2004, and 2005. After the in-field survey, soil properties for sampled field locations were also collected from the U.S. Department of Agriculture Natural Resources Conservation Service Web Soil Survey. GR horseweed predictions used in-field presence of crop residues and the appearance, abundance, and distribution of weeds in the field. The significance of independent data factors were determined by chi-square statistics. The interactions and relative significance of multiple factors were modeled using classification and regression tree analysis. Our results indicated that the most important factor for predicting GR populations was the identification of an altered plant phenotype after injury from POST glyphosate. This was followed by crop rotation, field distribution, and the presence of other escaped weed species in the field in a model with a classification rate of 0.68.
Integrating Cropping Systems with Cultural Techniques Augments Wild Oat (Avena fatua) Management in Barley
Authors: Harker K. Neil , O'Donovan John T. , Irvine R. Byron , Turkington T. Kelly , Clayton George W.
Published: May 2009

Wild oat causes more crop yield losses and accounts for more herbicide expenditures than any other weed species on the Canadian Prairies. A study was conducted from 2001 to 2005 at four Canadian Prairie locations to determine the influence of repeated cultural and herbicidal management practices on wild oat population density, biomass, and seed production, and on barley biomass and seed yield. Short or tall cultivars of barley were combined with normal or double barley seeding rates in continuous barley or a barley–canola–barley–field-pea rotation under three herbicide rate regimes. The same herbicide rate regime was applied to the same plots in all crops each year. In barley, cultivar type and seeding rate were also repeated on the same plots year after year. Optimal cultural practices (tall cultivars, double seeding rates, and crop rotation) reduced wild oat emergence, biomass, and seed production, and increased barley biomass and seed yield, especially at low herbicide rates. Wild oat seed production at the quarter herbicide rate was reduced by 91, 95, and 97% in 2001, 2003, and 2005, respectively, when tall barley cultivars at double seeding rates were rotated with canola and field pea (high management) compared to short barley cultivars at normal seeding rates continuously planted to barley (low management). Combinations of favorable cultural practices interacted synergistically to reduce wild oat emergence, biomass and seed production, and to increase barley yield. For example, at the quarter herbicide rate, wild oat biomass was reduced 2- to 3-, 6- to 7-, or 19-fold when optimal single, double, or triple treatments were combined, respectively. Barley yield reductions in the low-management scenario were somewhat compensated for by full herbicide rates. However, high management at low herbicide rates often produced more barley than low management in higher herbicide rate regimes.
Primary CNS Lymphoma in Immunocompetent Patients
Authors: Sierra del Rio Monica , Rousseau Audrey , Soussain Carole , Ricard Damien , Hoang-Xuan Khê
Published: May 2009

Primary central nervous system lymphoma (PCNSL) constitutes a rare group of extranodal non-Hodgkin’s lymphomas (NHLs), primarily of B cell origin, whose incidence has markedly increased in the last three decades. Immunodeficiency is the main risk factor, but the large majority of patients are immunocompetent. Recent evidence suggests a specific tumorigenesis that may explain their particular clinical behavior compared with systemic NHL. The addition of i.v. high-dose methotrexate (MTX) chemotherapy to whole-brain radiotherapy (WBRT) has considerably improved the prognosis, leading to a threefold longer median survival time compared with WBRT alone and represents the current standard of care. However, this combined treatment exposes the patient, especially the elderly, to a high risk for delayed neurotoxicity. In the older population (>60 years), there is growing evidence that MTX-based chemotherapy alone as initial treatment is the best approach to achieve effective tumor control without compromising patient quality of life. In the younger population, the risk for neurotoxicity is much lower, and this strategy is controversial because it may be associated with higher relapse rates. Future efforts should focus on the development of new polychemotherapy regimens allowing the reduction or deferral of WBRT in order to minimize the risk for delayed neurotoxicity. In this setting, intensive chemotherapy with autologous blood stem cell transplantation was recently demonstrated to be feasible and efficient as salvage therapy and is currently being evaluated as part of primary treatment. This review highlights the recent advances in the pathogenesis and treatment of PCNSL in the immunocompetent population.
Transcriptional targets for pituitary tumor-transforming gene-1
Authors: Tong Yunguang , Eigler Tamar
Published: May 2009

Pituitary tumor-transforming gene-1 (PTTG1) is a transforming gene first discovered in rat pituitary tumor cells. It possesses transcriptional activity and also has securin functions. Chromatin immunoprecipitation-on-chip study reveals that PTTG1 is a global transcription factor, which exerts its transcriptional activity either by directly binding to DNA or by interacting with proteins including PTTG1 binding factor, p53, Sp1, and upstream stimulatory factor 1. PTTG1 has several validated transcriptional targets that are involved in different cellular processes. PTTG1 activates c-Myc in NIH 3T3 cells, suggesting a role in cell transformation. PTTG1 induces fibroblast growth factor 2 expression and promotes tumor angiogenesis.It binds to and inhibits p53 transcriptional activity. PTTG1 activates cyclin D3 and represses p21 expression, indicating a role in cell cycle regulation and cell senescence. Here, we review PTTG1 transcriptional targets and their functions.
Alfacalcidol prevents aromatase inhibitor (Letrozole)-induced bone mineral loss in young growing female rats
Authors: Mohamed Idris , Yeh James K
Published: May 2009

Long-term aromatase inhibitor use causes bone loss and increases fracture risk secondary to induced estrogen deficiency. We postulated that alfacalcidol (A; vitamin D3 analog) could help prevent the Letrozole (L)-induced mineral bone loss. Fifty intact 1-month-old female rats were randomly divided into basal group; age-matched control group (AMC); L group: oral administration of 2 mg/kg per day; A group: oral administration of 0.1 μg/kg per day; and group L+A for a period of 8 weeks. Eight-week administration of L resulted in a significant increase in body weight, bone length, bone area, bone formation, and bone resorption activities when compared with the AMC group. However, the bone mass and bone mineral density (BMD) were significantly lower than the AMC group. Serum levels of testosterone, LH, FSH, and IGF-1 were significantly higher and serum estrone and estradiol were lower along with a decrease in ovary+uterus horn weight, when compared with the AMC groups. None of those parameters were affected by A treatment, except suppression of bone resorption activities and increased trabecular bone mass and femoral BMD, when compared with the AMC group. Results of L+A combined intervention showed that bone length, bone area, and bone formation activities were higher than the AMC group, and the bone resorption activities were lower and BMD was significantly higher than that of the L group. This study demonstrates that the combined intervention of L and A not only enhances bone growth, but also increases bone density, and the effects of L and A are independent and additive.
A Numerical Study of Solid Suspension Layers in a Swirl Fluidised Bed Reactor
Authors: Zhang Wei
Published: May 2009

Threedimensional numerical simulations of an isothermal swirl fluidised bed (SFB) system with no chemical reactions were performed to study the swirl decay process and its effects on bed performance, i.e. particle concentration in the freeboard. The commercial CFD code package ANSYS 11.0 was chosen to carry out our simulation. We used 200?m glass beads with property similar to Geldart group A particles as the particulate phase with assumption that they are cohesionless and mono-dispersed, and air at 25°C as the gas phase in our simulation. Different initial swirl intensities were controlled by varying the secondary gas velocities. The solids volume fraction of solids suspension layers in the freeboard agreed generally well with literature description, which showed an annular shape with high values near the wall side. For the first time, swirl intensity and its decay process were predicted numerically by incorporating a swirl number function into ANSYS 11.0 and its effects on the bed fluid dynamics were also discussed in a qualitative or semi-quantitative manner.
CFD Simulation of Solid Hold-Up in Gas-Solid Fluidized Bed at High Gas Velocities
Authors: Hosseini Seyyed Hossein , Zivdar Mortaza , Rahimi Rahbar , Samimi Abdolreza
Published: May 2009

CFD simulation results of gassolid fluidized bed using 2D EulerianEulerian approach at high gas velocities integrating the kinetic theory of granular flow are presented. The range of gas velocities are from 0.35 to 2.19m/s. Predicted particle motion and bubble behavior in the bed are consistent with the literature data. Simulation results indicate that Arastoopour's drag model is the best choice for the current system. Laminar flow and turbulent models, standard k-? and Simonin, are compared at Ug = 2.19m/s. CFD results show that Simonin model can be used at high gas velocities, reasonably. Current model reduces simulations errors compared with previous works. The minimum error is 6.5% and the maximum error is 13% in lower and upper part of the bed in radial direction, respectively.
Detection and Characterization of N-Glycolyated Gangliosides in Wilms Tumor by Immunohistochemistry
Authors: Scursoni Alejandra M. , Galluzzo Laura , Camarero Sandra , Pozzo Norma , Gabri Mariano R. , de Acosta Cristina Mateo , Vázquez Ana María , Alonso Daniel F. , de Dávila María Teresa G.
Published: May 2009

Gangliosides are glycolipids present on the cell surface. The N-glycolylated ganglioside NeuGc-GM3 has been described in some neoplasms, such as breast carcinoma and melanoma, but is usually not detected in normal human cells. Our aim was to evaluate the presence of NeuGc-GM3 in Wilms tumor by immunohistochemistry. Postchemotherapy tumors were grouped into different histologic subtypes considering the main preserved component. Formalin-fixed, paraffin-embedded tumor samples were cut into 5-μm sections. The monoclonal antibody 14F7, a mouse IgG1 that specifically recognizes NeuGc-GM3, and a peroxidase-labeled polymer conjugated to secondary antibodies were used. Sections from breast carcinoma were employed as positive controls. Presence of NeuGc-GM3 was evident in 22 of 25 (88%) cases. The staining was stronger in the epithelial component, with a membrane pattern and cytoplasmic diffusion. The stromal component expressed cytoplasmic NeuGc-GM3 in cells with rhabdomyoblastic differentiation. Tubules of adjacent renal tissue were also positive, but no expression of NeuGc-GM3 was detected in nontumoral fetal kidney. Until now, the expression of N-glycolylated gangliosides in pediatric solid tumors has not been investigated. The present study evidenced the expression of NeuGc-GM3 in a high proportion of Wilms tumors, suggesting its potential utility as a specific target of immunotherapy.
Comparison of Attitudes between Generation X and Baby Boomer Veterinary Faculty and Residents
Authors: Freeman Lisa M. , Trower Cathy A. , Tan Rachael J.B. , Terkla Dawn Geronimo
Published: May 2009

Understanding the characteristics and preferences of the different generations in the veterinary workforce is important if we are to help optimize current and future veterinary schools and teaching hospitals. The purpose of this study was to compare the attitudes of different generations of veterinary faculty and those of faculty and house officers. A survey administered to faculty and house officers asked respondents to identify their level of agreement with a series of statements addressing work and lifestyle issues and feedback preferences. In addition, the survey included an open-ended question on non-monetary rewards for hard work. Thirty-eight of 48 faculty members (79%) and 45 of 54 house officers (83%) completed the survey. Among faculty, there were no significant differences between the Generation X and Baby Boomer subgroups or between genders. More faculty than house officers responded that delayed gratification is acceptable (p = 0.03) and that it is difficult to balance home and work life (p < 0.001). Compared to faculty, house officers preferred more frequent (p = 0.03) and critical (p = 0.02) feedback. The most common responses to the question on effective non-monetary rewards for hard work, from both faculty and house officers, were recognition and time off. No attitudinal differences were detected between generations within the faculty group, but a number of significant differences emerged between faculty and house officers. Increased awareness of the importance of balance and rewards for hard work, as well as modification of feedback styles, may be beneficial in teaching and mentoring current and future generations.
Unleashing the Potential: Women's Development and Ways of Knowing as a Perspective for Veterinary Medical Education
Authors: Taylor Kay Ann , Robinson Daniel C.
Published: May 2009

Women now dominate student enrollment in colleges of veterinary medicine in the USA, as well as in other countries. Projections indicate that this will remain a constant. The implications for teaching, learning, mentoring, leadership, professional development, student and faculty diversity, and curriculum structure are enormous. This article provides the groundwork for examining gender diversity in veterinary medical education. Women's development and ways of knowing are identified as paramount for understanding and benefiting students and faculty in their higher education experiences and in their professional lives. Seminal research focusing on women's development and ways of knowing is introduced, summarized, and contrasted to male-centered models, and implications for teaching practice are considered. Our underlying premise is that research about women's moral and intellectual development is relevant to veterinary education and supports the adoption of student-centered approaches to teaching and learning.
Teaching Dairy Production Medicine to Entry-Level Veterinarians: The Summer Dairy Institute Model
Authors: Nydam Charles W. , Nydam Daryl V. , Guard Charles L. , Gilbert Robert O.
Published: May 2009

Food supply veterinarians who intend to enter dairy cattle practice or other related career activities are in need of up-graded skills to better serve the dairy industry as it continues to evolve. The time available for students to increase their abilities within the conventional professional curriculum is scarce, especially as those with food-supply interests are a minority of students competing for time and resources. The dairy industry has need of skilled veterinarians who are not only well versed in their traditional capabilities, but who also have an understanding of the complete picture of that industry as a “farm-to-fork” experience. Society at large also stands to benefit from the presence of skilled dairy veterinarians contributing to the production of safe, affordable dairy foodstuffs in a manner deemed sustainable and humane. Veterinarians in practice can and do acquire the necessary skills to make themselves relevant to their clients and consumers; however, better preparation of entry-level veterinarians could increase their value to their employers, clients, themselves, and society in a more timely manner. Cornell University's College of Veterinary Medicine developed the Summer Dairy Institute to provide an avenue for advancing the skills of new veterinarians as a means to address the current and future needs of the dairy industry. This article describes the need for, concept of, and experience with that program.
Craniosynostosis in Egypt
Authors: El-Sherif Hassanein , Khalifa Ahmed Samy , Abou-Senna Abdel Moneim , Ghaly Adley Farid
Published: May 2009

✓ In 25 Egyptian patients 2 to 18 years of age, craniosynostosis was studied clinically, radiologically, and biochemically. Oxycephaly was the most common manifestation, but single suture synostosis occurred occasionally. Increased intracranial pressure was marked (76%), clinically, radiologically, and at operation. Biochemical changes in the form of increased alpha-1 globulin and alpha lipoproteins, and reversed beta/alpha ratio of lipoproteins, pointed to a mesenchymal defect. Linear craniectomy proved satisfactory in many cases. Deroofing of the optic foramina and orbital decompression did not improve results. The symmetrical limitation of skull growth in oxycephaly resulted in late presentation of the case for treatment. Development of more widespread pediatric care in the United Arab Republic is needed for earlier recognition.
Cystometry as an adjunct in the evaluation of lumbar disc syndromes
Authors: Rosomoff Hubert L. , Johnston John D. H. , Gallo Anthony E. , Ludmer Mario , Givens Frederick T. , Carney Frank T. , Kuehn Conrad A.
Published: May 2009

✓ One hundred patients with the provisional diagnosis of nerve root compression in the lumbar spine were subjected to routine bladder evaluation by cystometry in addition to the standard somatic neurological examination. Eighty-three were found to have cystometrograms characteristic of bladder hypofunction. Residual urine was found in 20% of the 100 patients. By contrast, the examination of the somatic nervous system disclosed sensory deficits in 36%, weakness in 59%, reflex alterations in 66%, and positive sciatic-stretch tests in 69%. Almost all cystometric studies (96%) became normal after successful surgical or conservative therapy. It is concluded that occult bladder dysfunction is a major manifestation of lumbar nerve root compression. The neurophysiological mechanisms involved are discussed in detail.
Carotid-basilar venous plexus fistulas
Authors: Graf Carl J.
Published: May 2009

✓ The clinical and angiographic findings in two patients with arteriovenous fistulas involving the carotid artery and the basilar venous system are described. Related reports and the problems of management are also discussed.
General and local hypothermia of the brain in the treatment of intractable epilepsy
Authors: Šourek K. , Trávníček V.
Published: May 2009

✓ Twenty-five cases of intractable epilepsy were treated by combined deep general and local extravascular brain hypothermia plus single doses of pentothal (Thiopental) or diazepam. The final local temperature of the brain in 21 patients was below 24°C, the rectal temperatures being 27° to 30°C. There was one death 6 weeks after surgery, and in two patients slight neurological deficits were found at 3 and 6 months postoperatively.

In 15 patients in whom at least 1 year had elapsed since surgery, the frequency and intensity of the seizures were reduced by 50% in two, reduced to a single seizure in five, eliminated in four, and unaltered in four. The fair and excellent results included 60% of the group. In three patients improvement in behavior and emotional stability were observed postoperatively; this change was independent of the reduction of the frequency of seizures. Postoperative changes in the electroencephalogram were less frequent than changes in the frequency of seizures and also were completely independent of the clinical results.
Demonstration of an astrocyte-specific cerebroprotein by an immunofluorescence study of human brain tumors
Authors: Benda Philippe , Mori Takesada , Sweet William H.
Published: May 2009

✓ Specimens of 16 human brain tumors were studied by the indirect fluorescent-antibody technique to reveal the localization of the particular cerebroprotein found in strikingly increased amounts in human glial tumors as well as in the brain of a patient with Tay-Sachs disease. The cerebro-protein fraction named “10B” by Bogoch was found exclusively in reactive astrocytes, both in astrocytomas and in glioblastomas multiforme. Both the cytoplasm and the cell processes fluoresced upon exposure to antiserum to the “10B” proteins of Tay-Sachs disease. Fluorescence of fibrillary astrocytes located in white matter at some distance from a tumor might be related to discrete edematous changes or constitute an early step in the transition of normal glia to reactive or neoplastic astrocytes. There was no such staining of frankly neoplastic cells or of normal ganglion cells.
Effects of temporary occlusion of a vertebral artery on the human vestibular system
Authors: Nagashima Chikao , Iwama Kazuo , Sakata Eiji , Miki Yoshimasa
Published: May 2009

✓ Vestibular responses elicited by temporary occlusion of one vertebral artery were observed in 25 cases of intermittent vertebral artery compression (Power's syndrome) during surgical treatment by periarterial denervation of an isolated vertebral artery. This produced manifold varieties of spontaneous nystagmus, ocular movements without noticeable pupillary changes; the ocular manifestations included coarse vertical nystagmus, monocular horizontal nystagmus, convergence nystagmus, and conjugate or disconjugate eye movements. Subjective symptoms were observed in only approximately one half of the cases. These results support the concept that the vestibular nuclei as well as the oculomotor system in the brain stem are particularly sensitive to reduced blood flow through the vertebrobasilar arterial system. Examination of nystagmus under Frenzel glasses proved to be one of the most sensitive tests in evaluating the circulatory status of the brain stem.
Vasospasm in response to repeated subarachnoid hemorrhages in the monkey
Authors: Weir Bryce , Erasmo Ramon , Miller Jack , McIntyre John , Secord David , Mielke Bruce
Published: May 2009

✓ This study investigates the relationship between vasospasm and repeated subarachnoid hemorrhages in 18 monkeys. Sixteen received weekly 4 cc injections of autogenous blood into the subfrontal subarachnoid space. The weekly mortality rate for 4 weeks was 6%, 33%, 20%, and 37% respectively. The over-all mortality was 75%. The degree of vasospasm did not correlate with the morbidity and mortality. Vasospasm was limited to the intradural cerebral vessels and was diffuse. It never lasted longer than a few hours, late vasospasm did not occur, and the degree of vasospasm did not alter with repeated occasions of “subarachnoid hemorrhage.” Immediate electrocardiogram abnormalities were related to the height of the cerebrospinal fluid pressure rise following the subarachnoid hemorrhage (injected blood). Pathological examination of the vessels shown to be in spasm was normal. The study suggests that the increased mortality associated with repeated subarachnoid hemorrhage is due to cumulative structural damage rather than a heightened vasospastic response to repeated hemorrhages.
The size of intracranial saccular aneurysms
Authors: McCormick William F. , Acosta-Rua Gaston J.
Published: May 2009

✓ An autopsy study was made of the size of 191 saccular intracranial aneurysms (54 ruptured, 137 unruptured). Variations with age and sex, and ruptured and unruptured state were recorded and analyzed. Measurements on unfixed, unruptured aneurysms inflated by perfusion under 70 mm Hg pressure indicated that the size of aneurysms as generally determined in autopsy material is deceptively low.
Tumors of the optic nerve and optic chiasm
Authors: MacCarty Collin S. , Boyd Allen S. , Childs Donald S.
Published: May 2009

✓ In a series of 20 cases of glioma of the optic nerve, approximately 25% were successfully treated surgically. This series also confirms the observations of Taveras, et al., (1956) that 25% of patients thus treated obtain considerable additional improvement in vision after radiation therapy, and that another 10% derive minimal benefit.
Cerebral acid-base and gas metabolism in brain injury
Authors: Zupping R.
Published: May 2009

✓ Acid-base and gas parameters of CSF, jugular venous and arterial blood were measured in 45 patients with brain injury in the first 12 days after trauma or operation. CSF metabolic acidosis together with respiratory alkalosis and hypoxemia in the cerebral venous and arterial blood were the most characteristic findings. A close correlation between the severity of brain damage and the intensity of the CSF metabolic acidosis and arterial hypocapnia was revealed. It was concluded that brain hypoxia and acidosis play an important role in the development of cerebral edema and permanent brain damage.
Human choroid plexus: a light and electron microscopic study
Authors: Dohrmann George J. , Bucy Paul C.
Published: May 2009

✓ Specimens of human choroid plexus, obtained during craniotomy, were examined by light and electron microscopy. Inclusions were observed within the cytoplasm of the choroidal epithelial cells, and could be classified into three types on the basis of morphological characteristics. Each inclusion type predominated in a particular age group. In choroid plexuses of older humans, filaments from 60 to 150 Å in diameter, with no apparent periodicity, were noted circumjacent to the intracytoplasmic inclusions.
Delayed apoplexy following head injury (“traumatische Spät-Apoplexie”)
Authors: Morin Marc A. , Pitts Frederick W.
Published: May 2009

✓ The authors present their experience with three cases of delayed apoplectiform reaction to head injury. Two cases were operated on successfully, and the findings are compared with those previously reported. Pathogenesis, diagnosis, and management are discussed.
Total removal of large global meningiomas at the medial aspect of the sphenoid ridge
Authors: Cook Albert W.
Published: May 2009

✓ An operative technique for total removal of large global meningiomas at the medial aspect of the sphenoid ridge is described, and experience with 11 patients reported. The technique involves extradural liberation of the dural and tumor attachments to the underlying bone, and extradural occlusion of the blood supply through bone and middle meningeal artery. Subsequent procedures are carried out sequentially in the parasellar area to free the optic nerve and carotid, in the subtemporal tentorial region to release tumor from neighboring structures, and in the Sylvian fissure to isolate the middle cerebral artery.
Depilatory as initial preparation for craniotomies
Authors: Williams Phillip E. , Clark Kemp
Published: May 2009

✓ Surgex, a commercially available depilatory agent, has been used routinely in the preparation of the head for craniotomy. Its use eliminates problems that exist when the head is shaved with a razor. No complications of its use have been noted in approximately 400 cases.
Angle-meter to indicate the proper angle of insertion in anterior percutaneous cervical cordotomy
Authors: Gildenberg Philip L.
Published: May 2009

✓ An angle meter has been devised to facilitate the anterior approach to lower cervical percutaneous cordotomy and to afford the operator increased accuracy in placing the needle electrode. A method is described which allows the operator to set the trajectory of the needle electrode accurately at the stage when only the tip of the needle is inserted into the disc. The procedure requires no mathematical calculations and has proved accurate in 40 cases.
Isolation and characterization of glioblastoma nuclei and chromosomes in the lyophilized state
Authors: Kirsch Wolff M. , Schulz Demoy , Nakane Paul , Lasher Robert , Yamamoto Tadami
Published: May 2009

✓ Intact lyophilized nuclei and chromosomes were obtained from glioblastomas or brain, either in situ or in culture, by freezing at −156°C, drying at −25°C, and mechanical disassociation in glycerol at 2°C. Nuclear or chromosomal isolation was accomplished in hygroscopic nonaqueous media of high density. The method gave homogeneous nuclear and chromosomal preparations in high yield with preservation of labile, water-soluble constituents and residual biosynthetic activity. Unique opportunities for quantitative cytochemical studies at the level of the subcellular organelle are made available by the method.
The use of tissue culture in differentiation between angioblastic meningioma and hemangiopericytoma
Authors: Muller Jans , Mealey John
Published: May 2009

✓ A solid, extrinsic hemangiopericytoma of the cerebellopontine angle was studied histologically and by means of tissue culture. The explanted tumor cells formed classic meningiomatous whorls indicative of the meningeal derivation of this neoplasm. Whorls were entirely absent in the histological preparations, however. The cases reported under the diagnosis of intracranial hemangiopericytoma and angioblastic meningioma have been reviewed; no valid histological distinction between these two types could be made.
Combined extra-intradural temporal rhizotomy for the treatment of trigeminal neuralgia
Authors: Morello Giulio , Bianchi Mario , Migliavacca Franco
Published: May 2009

✓ The authors describe a modified temporal trigeminal rhizotomy whereby the fifth nerve root is approached extradurally and then reached intradurally. The results obtained in 409 cases of trigeminal neuralgia are summarized. The method has no greater risks than the extradural method and has the advantage of a lower incidence of postoperative facial paralysis and a greater chance of sparing the motor root.
Experimental Pantopaque ventriculography
Authors: Clark Ronald G. , Milhorat Thomas H. , Stanley Walter C. , Di Chiro Giovanni
Published: May 2009

✓ The injection of Pantopaque into the ventricles of normal and hydrocephalic dogs produced a variety of acute and chronic pathological changes. Multiple granulomatous lesions developed in the ventricular wall and the surrounding brain parenchyma, choroid plexus, cranial nerves, and arachnoid membrane. Adhesions formed in several areas of the ventricles, and Pantopaque became encysted in the third ventricle and tips of the temporal horns. In general there were more serious changes in the animals that had a greater degree of hydrocephalus. Relatively mild lesions were noted in normal animals.
Cerebral function during profound oligemic hypotension in the dog
Authors: Yashon David , Locke George E. , Bingham W. George , Wiederholt Wigbert C. , Hunt William E.
Published: May 2009

✓ Electrocortigraphic activity and common carotid blood flow were studied in 12 dogs during and following profound oligemic hypotension. Five animals survived but seven died within 75 min of hypotension. Although an 80% to 90% reduction in both mean arterial pressure and common carotid blood flow was observed, only a 20% diminution of intracranial pressure occurred and there was little change in electrocorticographic function. The preservation of cerebral function in the presence of profound systemic hypotension was demonstrated. When death occurred during shock, no prior change in central nervous system function was noted. With reinfusion, no change in parameters was noted, but common carotid blood flow was depressed to 35% to 50% of control levels for up to 2½ hrs of observation.
Cerebral paragonimiasis
Authors: Higashi Kenichiro , Aoki Hideo , Tatebayashi Kinichiro , Morioka Hisashi , Sakata Yozo
Published: May 2009

✓ The authors report 10 cases of cerebral infestation with paragonimiasis westermani seen in Ube, Japan, from 1954–1968. Nine were treated surgically. The clinical, roentgenological, parasitic, and pathological characteristics are described and discussed in detail as well as the surgical and chemotherapeutic management.
Paraplegia following thoracolumbar sympathectomy
Authors: Shallat Ronald F. , Klump Thomas E.
Published: May 2009

✓ A case is presented in which a bilateral thoracolumbar sympathectomy and splanchnicectomy were followed by permanent paraplegia below T-10. The hypothesis is presented that coagulation of a bleeding intercostal vessel during surgery led to a propagating thrombus which involved, successively, the intercostal artery, a segmental medullary vessel, and the anterior spinal artery with resulting spinal cord infarction. Other possible mechanisms are mentioned. Several technical suggestions are offered with regard to prevention of this complication.
Use of centrifuge in the treatment of an intraventricular metallic foreign body
Authors: Markham James W. , Stein Seymour , Pelligra Ralph , Lippe Philipp , Noyes Jack
Published: May 2009

✓ A bullet fragment within the ventricular system was immobilized by use of centrifugation in a 5°-of-freedom-of-motion simulator at 4 to 6 G's. Transient cardiovascular changes occurred, but there were no ill effects clinically. The bullet fragment was immobilized within the ependyma of the left lateral ventricle and has remained in a fixed position during a 22-month follow-up period. A brief review of the treatment of intraventricular foreign bodies is included.
The neurosurgical treatment of glomus jugulare tumors
Authors: Kempe Ludwig G. , VanderArk Gary D. , Smith Donald R.
Published: May 2009

✓ Glomus jugulare tumors are discussed with regard to diagnosis and treatment. These tumors, although usually benign, may be fatal because of their location. Therefore, accurate classification by location, size, and the blood supply of the mass is important; use of newer roentgenographic techniques provides key information. Surgical removal is recommended as the treatment of choice. The neurosurgical technique of en bloc excision of glomus jugulare tumors is described and illustrated.
K-shell fluorescence for the study of regional cerebral blood flow
Authors: Moody Robert A. , Hoffer Paul B. , Polcyn Robert E. , Lowe Henry J. , Gottschalk Alexander , Dobben Glen D.
Published: May 2009

✓ A new method for determining regional cerebral blood flow is reported which utilizes K-shell fluorescence and thus avoids administration of radioactive materials to a patient. Due to its inherent laminographic features, K-shell fluorescence escapes interference from scalp and skull, while giving a true demonstration of regional flow. It is applicable to either clearance time or transit time techniques. The tracer can be administered either by inhalation or intra-arterial injection. The present study demonstrates its feasibility for use in both animals and humans.
Survival following gunshot wound of the pons: neuroanatomic considerations
Authors: Kline David G. , Leblanc Hector J.
Published: May 2009

✓ The successful treatment of a civilian gunshot wound of the vermis and pons is described. A large missile fragment was removed from a depth of 2 cm within the pons at the level of the facial colliculus. Despite initial coma and subsequent irregular respiration with sleep apnea, the patient survived. Neurological, radiographic, and operative findings are correlated with the anatomy of the pons.
Spontaneous carotid-cavernous shunts presenting diagnostic problems
Authors: Taniguchi Raymond M. , Goree John A. , Odom Guy L.
Published: May 2009

✓ The diagnostic and therapeutic problems of 11 patients who presented the form fruste of a carotid cavernous fistula, that is, mild proptosis and conjunctival injection sometimes without a bruit, are discussed. Carotid angiography revealed a peculiar arteriovenous shunting in the region of the cavernous sinus, which may be overlooked since it does not resemble the classic picture of a carotid cavernous fistula. All 11 cases were of spontaneous onset. These fistulas appear to be more common in women who are postmenopausal, pregnant, or post-abortive. The etiology of these fistulas is uncertain but several theories are discussed. Conservative treatment is recommended unless there is an exacerbation of symptoms or the patient has a progressive loss of vision.
Neurenteric cyst in the cervical spinal canal of a 10-week-old boy
Authors: Klump Thomas E.
Published: May 2009

✓ A 10-week-old infant was found to have a cervicothoracic intradural neurenteric cyst which was operated on with resolution of the neurological symptoms. The discussion centers on the nature of the lesion and its possible pathogenesis.