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Laws of Conservation as Related to Brain Growth, Aging, and Evolution: Symmetry of the Minicolumn
Manuel F. Casanova
Frontiers in Neuroanatomy , 2011, DOI: 10.3389/fnana.2011.00066
Abstract: Development, aging, and evolution offer different time scales regarding possible anatomical transformations of the brain. This article expands on the perspective that the cerebral cortex exhibits a modular architecture with invariant properties in regards to these time scales. These properties arise from morphometric relations of the ontogenetic minicolumn as expressed in Noether’s first theorem, i.e., that for each continuous symmetry there is a conserved quantity. Whenever minicolumnar symmetry is disturbed by either developmental or aging processes the principle of least action limits the scope of morphometric alterations. Alternatively, local and global divergences from these laws apply to acquired processes when the system is no longer isolated from its environment. The underlying precepts to these physical laws can be expressed in terms of mathematical equations that are conservative of quantity. Invariant properties of the brain include the rotational symmetry of minicolumns, a scaling proportion or “even expansion” between pyramidal cells and core minicolumnar size, and the translation of neuronal elements from the main axis of the minicolumn. It is our belief that a significant portion of the architectural complexity of the cerebral cortex, its response to injury, and its evolutionary transformation, can all be captured by a small set of basic physical laws dictated by the symmetry of minicolumns. The putative preservations of parameters related to the symmetry of the minicolumn suggest that the development and final organization of the cortex follows a deterministic process.
THE NEUROPATHOLOGY OF AUTISM: A SELECTIVE REVIEW
Manuel F. CASANOVA,Meghan MOTT
Journal of Special Education and Rehabilitation , 2006,
Abstract: Autism is a neurodevelopmental disorder charac-terized by impairments in cognitive, language and social skills. While the etiology remains unclear, it is viewed primarily as a highly heritable disorder. In this article, characteristic neuroanatomical mor-phological findings associated with autism are se-lectively reviewed and their implications for be-havioral manifestations are discussed. Although there is general consistency among the classic neu-ropathological observations, conflicting findings are a feature of the literature. All studies suffer from small sample size and the high comorbidity of autism with other neurological/psychiatric dis-eases. Larger study populations due in part to in-creased prevalence and awareness of autism allow for greater statistical power validity. New imaging and postmortem techniques employed in these studies hold out the promise of resolving conflicts and ambiguities in the data, providing a basis for enhanced understanding of the neuropathology and treatment of this condition.
HYPERLEXIA AND DYSLEXIA IN AUTISM: HITTING A MOVING TARGET
Emily L. WILLIAMS,Manuel F. CASANOVA
Journal of Special Education and Rehabilitation , 2012,
Abstract: The diagnostic histories of autism, dyslexia, and hyperlexia are complex. Because these conditions share both convergent and diver-gent properties, it is important to under-stand these relationships, especially in the case of research and how we interpret bodi-es of work which span decades of fluc-tuating criteria. It is also important to syn-the-size what we already know about the morpho-logy of these con-di-tions and pinpoint what we still don’t. Autism and dyslexia, for instance, share antipodal cerebral morpho-logies, such as minicolumnar den-sity, neuropil width, cell size, corpus callo-sal volume, gyral complexity, gyral window size, and cerebral volume, while hyperlexia has not been studied in this fashion, although it sha-res much in common with autism. Mean-while, the fluctuation in criteria of dyslexia over the years, means that older studies, such as some of the most highly cited in post-mortem research, have potentially used more heterogeneous groups of subjects than dys-lexia research typically uses today. Con-sider-ably, these older studies are often the basis of current animal model and genetics research. In conclusion, in consideration of the continued flux in criteria, particularly the proposed change from “Reading Disorder” to the broa-der “Specific Learning Disorder” within the DSM-5, we strongly recommend a separation of the various reading disorders under their own headings to promote specificity of diag-nosis and treatment, and to support better research.
ABNORMALITIES OF THE GYRAL WINDOW IN AUTISM: A MACROSCOPIC CORRELATE TO A PUTATIVE MINICOLUMNOPATHY
Manuel F. CASANOVA,Aly FARAG,Ayman EL-BAZ,Meghan MOTT
Journal of Special Education and Rehabilitation , 2006,
Abstract: Autism is a neurodevelopmental disorder characterized by impairments in social interaction, language, and range of interests. Recent studies suggest that the brains of autistic patients have an increased number of minicolumns. This finding helps explain the presence of macroencephaly or increased brain size in a significant proportion of autistic patients. Changes in brain size and gyrification are usually concurrent. In this study we have implemented an algorithm that measured the gyrification window in the brains of 23 postmortem autistic and 16 postmortem control brains. At the 85% confidence level the algorithm correctly classified 22/23 autistics, a 0.96 accuracy rate, and 15/16 controls, a 0.94 accuracy rate. Previous structural neuroimaging studies in autism have emphasized volumetric measures. These methodologies are very sensitive to segmentation artifacts, being compromised by image noise, lack of strong edges, and sharing of color/texture among different structures. The present study offers a new approach to the classification of autism based on structural MRI.The finding bears relevance to the clinical presentation of autism as increased gyrification reduces the gyral window and constrains connectivity in favor of short corticocortical fibers.
Relaciones entre violencia escolar y autoconcepto multidimensional en adolescentes de Educación Secundaria Obligatoria Relationships between school violence and multidimensional self-concept: teenagers from the Obligatory Secondary Education.
Manuel J. de la Torre,Ma Cruz García,Ma de la Villa Carpio,Pedro F. Casanova
European Journal of Education and Psychology , 2008,
Abstract: Este trabajo tiene el objetivo de conocer las diferencias en autoconcepto desde una perspectiva multidimensional entre adolescentes implicados en la participación u observación de actos intimidatorios dentro del medio escolar (agresores, víctimas, agresores-víctimas y observadores). Para ello evaluamos a una muestra de 345 adolescentes con edades comprendidas entre los 14 y los 18 a os. Los resultados obtenidos indican que los agresores muestran una mejor autopercepción en las dimensiones emocional y social, el grupo de víctimas puntúa más alto en las dimensiones familiar y escolar, el grupo de agresores-víctimas presenta las puntuaciones más bajas en la dimensión familiar y escolar y ligeramente superior a las víctimas en la dimensión social y emocional. Por último, los observadores son los que mejor se perciben a sí mismos en la dimensión familiar y académica y por debajo ligeramente de los agresores en la dimensión emocional y social. Palabras clave: Violencia escolar, autoconcepto, adolescentes. The aim of this study is to understand the differences in self-concept from a multidimensional perspective among adolescents who have been participants or observers of acts of intimidation at school (aggressive, victims, aggressive-victims and observers). To this end, we assess a sample of 345 adolescents between the ages of 14 and 18. The results obtained indicate that in terms of self-perception, attackers showed higher scores in the emotional and social dimensions, victims scored higher in the family and academic dimensions, and aggressive-victims showed the lowest scores in the family and academic dimensions, and were slightly higher than victims in the social and emotional dimensions. Observers scored highest in self-perception in the family and academic dimensions, and were slightly lower than attackers in the emotional and social dimensions. Key words: School violence, self-concept, adolescents.
Detection of inverse Rashba-Edelstein effect at Cu/Bi interface using lateral spin valves
Miren Isasa,M. Carmen Martínez-Velarte,Estitxu Villamor,Luis Morellón,José M. De Teresa,Manuel R. Ibarra,Luis E. Hueso,Fèlix Casanova
Physics , 2014,
Abstract: The spin transport properties of bismuth (Bi) have been investigated using permalloy/bismuth/copper (Py/Bi/Cu) lateral spin valve structures. From spin absorption experiments, we show that the metallic surface of Bi acts as a strong spin sink. Moreover, we have measured a spin-to-charge current conversion that is attributed to the inverse Rashba-Edelstein effect (IREE) occurring at the Bi/Cu interface. By analyzing this spin-to-charge conversion as a function of temperature, the measurements exhibit a clear sign change at $\sim$ 125 K, corresponding to a change on the type of carriers dominating the electronic transport. These results evidence that the IREE arises from the spin splitting of the bulk states due to the Rashba effect at the metallic-Bi interface.
CARTOGRAFíA DE LAS PéRDIDAS POTENCIALES DE N-UREA POR VOLATILIZACIóN EN SUELOS DE CHILE CENTRAL
Casanova P,Manuel; Benavides Z,Carlos;
Revista de la ciencia del suelo y nutrición vegetal , 2009, DOI: 10.4067/S0718-27912009000100002
Abstract: available soil information from a soil cartography and a soil data base were used to predict the spatial distribution of ammonia volatilization by surface applied granular urea within the central zone of chile, assuming that the potential losses depends only on soil properties, which are associated with the physical space known as microsite. relevant properties (cation exchange capacity, urease activity, ph buffering capacity and soil ph post urea hydrolysis or phf) on ammonia loss process were defined according to a conceptual model, determining threshold values for high potential ammonia losses: cec ≤ 20 cmol(+) kg-1, urease activity ≥ 40 μg n-urea g-1 h-1 and phf ≥ 8.0. on other hand, considering the use of some simplified pedotransfer functions, these relevant properties were predicted for the cartographic units of 82 soil series, estimating around of 88,000 ha the area with the highest risk ammonia losses, corresponding principally to mollisols.
CARTOGRAFíA DE LAS PéRDIDAS POTENCIALES DE N-UREA POR VOLATILIZACIóN EN SUELOS DE CHILE CENTRAL Mapping potential losses of N-urea by volatilization in soils of central Chile
Manuel Casanova P,Carlos Benavides Z
Revista de la Ciencia del Suelo y Nutrición Vegetal , 2009,
Abstract: Empleando información cartográfica y una base de datos se predijo la distribución espacial de la volatilización a partir de urea granular aplicada superficialmente en la zona central de Chile, bajo el supuesto que el potencial de pérdida amoniacal sólo depende de las propiedades del suelo, y que se asocian al espacio físico conocido como micrositio. Las propiedades relevantes (capacidad de intercambio catiónico, actividad ureásica, tamponamiento del pH y pH del suelo post-hidrólisis de la urea o pH/) para el proceso de pérdida de amoníaco, se definieron acorde a un modelo conceptual, determinándose que los valores umbrales para un alto potencial de pérdidas son: CIC ≤ 20 cmol(+) kg-1, actividad ureásica ≥ 40 N-urea g-1 h-1 and pH ≥ 80. Por otra parte, teniendo en cuenta el uso de algunas funciones de pedotranferencia simplificadas, dichas propiedades relevantes fueron predichas para las unidades cartográficas de las 82 Series del suelo, estimándose en alrededor de 88.000 hectáreas el área con mayor riesgo de pérdidas de amoníaco, correspondiendo principalmente a Mollisoles. Available soil information from a soil cartography and a soil data base were used to predict the spatial distribution of ammonia volatilization by surface applied granular urea within the central zone of Chile, assuming that the potential losses depends only on soil properties, which are associated with the physical space known as microsite. Relevant properties (cation exchange capacity, urease activity, pH buffering capacity and soil pH post urea hydrolysis or pHf) on ammonia loss process were defined according to a conceptual model, determining threshold values for high potential ammonia losses: CEC ≤ 20 cmol(+) kg-1, urease activity ≥ 40 μg N-urea g-1 h-1 and pHf ≥ 8.0. On other hand, considering the use of some simplified pedotransfer functions, these relevant properties were predicted for the cartographic units of 82 soil Series, estimating around of 88,000 ha the area with the highest risk ammonia losses, corresponding principally to Mollisols.
Cuentos ciudadanos desarrollo de competencias ciudadanas y reconstrucción de imaginarios de ciudad y ciudadanía, a través del periodismo escolar
Manuel Jair Vega Casanova,Vanessa Castro Morales
Investigación y Desarrollo , 2006,
Abstract: Este artículo presenta los hallazgos de un proyecto de investigación- acción participativa, cuyo objetivo fue dise ar una estrategia de formación en competencias ciudadanas en ni as y ni os escolarizados de Barranquilla, para la reconstrucción de imaginarios de ciudad y ciudadanía a partir del periodismo escolar. El trabajo de campo se llevó a cabo a través de la técnica proyectiva del mapa mental, secciones de grupo y entrevistas realizadas por la población infantil (después de ser capacitada) a los adultos habitantes de sus barrios. Los resultados de la exploración permitieron construir hipótesis para establecer las tres fases de la estrategia: cuentos para la convivencia y paz, cuentos para la interculturalidad y cuentos para la participación-responsabilidad democrática. Se encontró que a partir de la experiencia directa con la ciudad y de la experiencia mediática, los habitantes configuran imágenes de una ciudad fragmentada y de una ciudadanía limitada a la obediencia de normas. De ahí que se propone la implementación y validación de la estrategia en las escuelas, con el fin de continuar fortaleciendo y visibilizando la capacidad crítica de los estudiantes para contar otro tipo de ciudad y de ciudadanía.
A Review of Traditional and Novel Treatments for Seizures in Autism Spectrum Disorder: Findings from a Systematic Review and Expert Panel
Richard E. Frye,Daniel Rossignol,Manuel F. Casanova,Gregory L. Brown,Stephen Edelson,Robert Coben,Jeffrey Lewine,John C. Slattery,Chrystal Lau,Paul Hardy,S. Hossein Fatemi,Derrick MacFabe
Frontiers in Public Health , 2013, DOI: 10.3389/fpubh.2013.00031
Abstract: Despite the fact that seizures are commonly associated with autism spectrum disorder (ASD), the effectiveness of treatments for seizures has not been well studied in individuals with ASD. This manuscript reviews both traditional and novel treatments for seizures associated with ASD. Studies were selected by systematically searching major electronic databases and by a panel of experts that treat ASD individuals. Only a few anti-epileptic drugs (AEDs) have undergone carefully controlled trials in ASD, but these trials examined outcomes other than seizures. Several lines of evidence point to valproate, lamotrigine, and levetiracetam as the most effective and tolerable AEDs for individuals with ASD. Limited evidence supports the use of traditional non-AED treatments, such as the ketogenic and modified Atkins diet, multiple subpial transections, immunomodulation, and neurofeedback treatments. Although specific treatments may be more appropriate for specific genetic and metabolic syndromes associated with ASD and seizures, there are few studies which have documented the effectiveness of treatments for seizures for specific syndromes. Limited evidence supports l-carnitine, multivitamins, and N-acetyl-l-cysteine in mitochondrial disease and dysfunction, folinic acid in cerebral folate abnormalities and early treatment with vigabatrin in tuberous sclerosis complex. Finally, there is limited evidence for a number of novel treatments, particularly magnesium with pyridoxine, omega-3 fatty acids, the gluten-free casein-free diet, and low-frequency repetitive transcranial magnetic simulation. Zinc and l-carnosine are potential novel treatments supported by basic research but not clinical studies. This review demonstrates the wide variety of treatments used to treat seizures in individuals with ASD as well as the striking lack of clinical trials performed to support the use of these treatments. Additional studies concerning these treatments for controlling seizures in individuals with ASD are warranted.
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