Management discriminant properties in semiarid soils

The physical properties of coarse - textured soils in semiarid regions often deteriorate with use. We hypostatized that the changes in the physical properties of the soil were related to the cropping sistem employed. 5urface sampled of 52 Entic Haplustolls under three diferents uses (24 under continuous cultivation), 18 under rotation wuth grass Ieys (R), and 10 virgin soils M were analyzed for c1ay, silt, organic malter anrd water content, bulk density, compaction and aggregate stability. Data were analyzed statistically using principal components, canonical variables, and discriminant functions. A satisfactory segregation of the soils according to discriminant properties (coarse organic matter, aggregate stability, and suceptibility lo compaction) was obtained. The model developed satisfactory classified the soils under different uses (100% R, 83% e, and 88% V). Principal component analysis also showed that bulck density, compaction, and wet aggregate salability are related lo organic matter content. We conclude that, in the studied region, the lower the ratio of organic matter lo clay + soil content, the more severe the physical deterioration of the soils.Resúmenes de Trabajos presentados en otras publicaciones (por docentes de la UNLPam.)Publicado en Soil Science, Vol 163 N°7

Phosphorus dynamic in ashes of the volcanoes Quizapu and Hudson and their nutrient content

Se presenta el contenido de algunos elementos minerales totales y disponibles en muestras de cenizas provenientes de las erupciones de los volcanes Quizapu y Hudson, en comparación con el de suelo adyacentes a las mismas y, en particular, su comportamiento en relación al fósforo. Los datos obtenidos revelan que las cenizas antes nombradas se diferencian mucho en su pH, presentando valores próximos a 5 y a 10 respectivamente, aunque no discrepan mucho en los contenidos de elementos analizados entre las cenizas del Quizapu y los suelos adyacentes a las mismas; sí, en cambio, contenidos menores en las cenizas del Hudson. El fraccionamiento de fósforo de las cenizas muestra predominio de Ca-P, y éstas están caracterizadas por elevados contenidos de fósforo disponible, lo que causa desorción de este nutriente.Total and available element contents in ash samples from the volcanoes Quizapu and Hudson in comparison to soil samples and their behavior in relation to phosphorous is presented. The obtained data show that the ashes differ much in their pH values, which are near 5 and 10 respectively, but there are not remarkable differences in the analyzed element contents between the Quizapu ash and the soil samples, and lower contents appear in that of the Hudson. The phosphorous fractionation of the ashes shows dominance of Ca-P, and they are characterized by high available phosphorous content which produces his desorption.Facultad de Ciencias Agrarias y Forestale

Relationships between site factors and the growth of conifers introduced in Ventania (Province of Buenos Aires), Argentina

Se evaluó la influencia de factores de sitio sobre el crecimiento de 22 rodales de pino de Alepo (Plnus halepensis MUI), 20 de pino de Monterrey (Plnus radiata D.Don.), 15 de cedro del Himalaya (Cedrus deociara (Roxb) Loudon) y 15 de ciprés horizontal (Cupressus sempervirens i. horizontal (Mid.) Voos), ubicados en una vasta área del sistema serrano de Ventania. Las variables edáficas correlacionadas con el índice de sitio como indicador del crecimiento, fueron: profundidad deenraizamiento y pedregosldad a 0-30 y 30-60 cm de profundidad en P. halepensis; pedregosidad y contenidos de gravas finas y gravillas, y de arena en C. deodara, y profundidad de enraizamiento y color (value) del horizonte A en C. sempervirens. Ningún factor edáfico se correlacionó significativamente con el crecimiento de P. radiata. Los modelos de regresión utilizando únicamente aspectos edáficos permitieron explicar entre 23 y 70% de la variabilidad en el índice de sitio. Entre las variables geográficas, topográficas y climáticas se encontraron correlacionadas con el creci­miento de las distintas especies: latitud, longitud, altitud, longitud e inclinación de la pendiente, posición en el relieve, precipitación, suma anual de déficits y superávits hídricos, temperatura media del mes más cálido y otras variables climáticas, las que tuvieron particular incidencia en P. radiata. Incluyendo todas las variables ambientales en forma conjunta, la explicación de la varianza del índicede sitio se elevó a 60-85% según la especie.It was studied the influence of site factors on growth of stands of Aleppo pine (Plnus halepensis. Mill.), 20 stands of Monterey pine (Pinos radiate D. Don.), 15 stands of deodar cedar (Cedros deodara (Roxb) Loudon) and 15 stands of itaiian or common cypress (Cupressus sempervirens f. horizontalis (Mill.) Voos), located in a large area of the hilly system of Ventania Soil variables correlated with site index as growth estimator were: depth of rooting and stoniness at a depth of 0-30 and 30-60 cm for P. halepensis, stoniness, and gravel and sand content for C. deodara and depth of rooting and cotor (value) of A horizon for C. sempervirens. No soil factor was significantly correlated with the growth of P. radiate. Regression models including soil variables explained between 23 and 70% of foe variation in site index. Growth of the studied species was correlated with foe following geographic, topographic and climatic variables: latitude, longitude, altitude, slope length and gradient, slope position, rainfall, annual sum of water deficits and surpluses, mean temperature of the warmest month and other climatic variables which mainly affected growth of P. radiata. Including all the environmental variables, the explanation of the variation in site index grew up to 60-85%.Facultad de Ciencias Agrarias y Forestale

Condiciones paleoclimáticas deducidas de indicadores pedológicos y geomorfológicos en la Región Pampeana Central (Argentina)

Algunas condiciones paleoclimáticas de la región pampeana fueron deducidas por medio de la interpretación de características geomorfológicas y pedológicas dé una transecta de 300 Km de longitud (65°05' W – 36°05' S a 62°05' W - 38°05' S) Y de un perfil con dos paleosuelos y tres capas de tosca respectivamente. Las características geomorfológicas fueron las mismas a lo largo de la transecta: planicies con tosca de aproximadamente 2 m de espesor en la parte superior, disectadas por valles. Hacia el W se detectaron dos niveles de planicies y valles sin drenaje integrado. Hacia el E se vió que las planicies están también coronadas con tosca, pero los valles pertenecen a un sistema de paleocauces con drenaje dentrítico, que desemboca en el Océano Atlántico. Los materiales finos dispuestos en el fondo de los valles y la disección de la tosca en sus bordes, hablan de una formación de estos por acción hídrica. El rellenado de los valles ubicados hacia el W con arena eólica, que frecuentemente producen una inversión del relieve, indican condiciones ambientales más secas. El perfil estudiado se encuentra ubicado en el extremo occidental de la transecta, posiblemente en el nivel de planicies más antiguas. La acción de climas con frecuentes periodos húmedos y secos se dedujo de a) las característica: del paleosuelo más profundo (estructura prismática, conteniendo abundancia de concreciones de Fe y Mn ) típicas  de un Bt de un planosol formado bajo condiciones alternativamente subhídricas y secas;  b) las características del paleosuelo superior (estructura poliédrica, contenidos de arcilla altos, concreciones de Fe y Mn) típicas de un Bt de un suelo de estepa, formado bajo condiciones estacionales alternativamente secas y húmedas; c) la génesis de la tosca "per descensum" bajo condiciones inicialmente húmedas (translocación del CaC03) y posteriormente secas (endurecimiento de la tosca), d) la acción del agua seguido por el viento en la formación de los valles. Amplitudes de humedad progresivamente menores de esos climas se dedujeron de a) la formación de un planosol más profundamente que un suelo de estepa en el mismo perfil, b) el incremento en la dureza y la relación Si:Ca hacia las toscas más profundas, e) el mayor contenido de concreciones de Fe y Mn en las porciones inferiores del perfil.Publicado en Zentralblatt für Geologie und paläentologie - Teil, 1987 (3/4): 1-9. Stuttgart

Nitrogen cycle disruption through the application of de-icing salts on upland highways

It is hypothesized that episodic introductions of road salt severely disrupt the soil nitrogen cycle at a range of spatial and temporal scales. A field-scale study has confirmed impacts on the nitrogen cycle in soil, soil solution and river samples. There is evidence that ammonium-N retention on cation exchange sites has been reduced by the presence of sodium ions, and that ammonium-N has been flushed from the exchange sites. Increases in soil pH have been caused in naturally acidic uplands. These have enhanced mineralization of organic-N, especially nitrification, leading to a reduction in the mineralizable-N pool of roadside soils. There is evidence to support the hypothesis that organic matter content has been lowered over decades either through desorption or dispersal processes. Multiple drivers are identified that contribute to the disruption of nitrogen cycling processes, but their relative importance is difficult to quantify unequivocally. The influence of road salt on soil and soil solution declines with distance from the highway, but impacts on water chemistry in a local stream are still strongly evident at some distance from the road

Autologous hematopoietic stem cell transplantation following high-dose chemotherapy for non-rhabdomyosarcoma soft tissue sarcomas (Review)

Background Soft tissue sarcomas (STS) are a highly heterogeneous group of raremalignant solid tumors.Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In patients with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy forHDCT-related severe hematologic toxicity. Objectives To assess the effectiveness and safety of HDCT followed by autologous HSCT for all stages of soft tissue sarcomas in children and adults. Search strategy We searched the electronic databases CENTRAL (The Cochrane Library 2010, Issue 2), MEDLINE and EMBASE (February 2010). Online trial registers, congress abstracts and reference lists of reviews were searched and expert panels and authors were contacted. Selection criteria Terms representing STS and autologous HSCT were required in the title, abstract or keywords. In studies with aggregated data, participants with NRSTS and autologous HSCT had to constitute at least 80% of the data. Comparative non-randomized studies were included because randomized controlled trials (RCTs) were not expected. Case series and case reports were considered for an additional descriptive analysis. Data collection and analysis Study data were recorded by two review authors independently. For studies with no comparator group, we synthesised results for studies reporting aggregate data and conducted a pooled analysis of individual participant data using the Kaplan-Meyer method. The primary outcomes were overall survival (OS) and treatment-related mortality (TRM). Main results We included 54 studies, from 467 full texts articles screened (11.5%), reporting on 177 participants that received HSCT and 69 participants that received standard care. Only one study reported comparative data. In the one comparative study, OS at two years after HSCT was estimated as statistically significantly higher (62.3%) compared with participants that received standard care (23.2%). In a single-arm study, the OS two years after HSCT was reported as 20%. In a pooled analysis of the individual data of 54 participants, OS at two years was estimated as 49% (95% CI 34% to 64%). Data on TRM, secondary neoplasia and severe toxicity grade 3 to 4 after transplantation were sparse. All 54 studies had a high risk of bias. Authors’ conclusions Due to a lack of comparative studies, it is unclear whether participants with NRSTS have improved survival from autologous HSCT following HDCT. Owing to this current gap in knowledge, at present HDCT and autologous HSCT for NRSTS should only be used within controlled trials

Mesoporous monoliths of inverse bicontinuous cubic phases of block copolymer bilayers

Solution self-assembly of block copolymers into inverse bicontinuous cubic mesophases is a promising new approach for creating porous polymer films and monoliths with highly organized bicontinuous mesoporous networks. Here we report the direct self-assembly of block copolymers with branched hydrophilic blocks into large monoliths consisting of the inverse bicontinuous cubic structures of the block copolymer bilayer. We suggest a facile and scalable method of solution self-assembly by diffusion of water to the block copolymer solution, which results in the unperturbed formation of mesoporous monoliths with large-pore (>25nm diameter) networks weaved in crystalline lattices. The surface functional groups of the internal large-pore networks are freely accessible for large guest molecules such as protein complexes of which the molecular weight exceeded 100kDa. The internal double-diamond (Pn3m) networks of large pores within the mesoporous monoliths could be replicated to self-supporting three-dimensional skeletal structures of crystalline titania and mesoporous silica.open2

New Insights into Alzheimer's Disease Progression: A Combined TMS and Structural MRI Study

BACKGROUND: Combination of structural and functional data of the human brain can provide detailed information of neurodegenerative diseases and the influence of the disease on various local cortical areas. METHODOLOGY AND PRINCIPAL FINDINGS: To examine the relationship between structure and function of the brain the cortical thickness based on structural magnetic resonance images and motor cortex excitability assessed with transcranial magnetic stimulation were correlated in Alzheimer's disease (AD) and mild cognitive impairment (MCI) patients as well as in age-matched healthy controls. Motor cortex excitability correlated negatively with cortical thickness on the sensorimotor cortex, the precuneus and the cuneus but the strength of the correlation varied between the study groups. On the sensorimotor cortex the correlation was significant only in MCI subjects. On the precuneus and cuneus the correlation was significant both in AD and MCI subjects. In healthy controls the motor cortex excitability did not correlate with the cortical thickness. CONCLUSIONS: In healthy subjects the motor cortex excitability is not dependent on the cortical thickness, whereas in neurodegenerative diseases the cortical thinning is related to weaker cortical excitability, especially on the precuneus and cuneus. However, in AD subjects there seems to be a protective mechanism of hyperexcitability on the sensorimotor cortex counteracting the prominent loss of cortical volume since the motor cortex excitability did not correlate with the cortical thickness. Such protective mechanism was not found on the precuneus or cuneus nor in the MCI subjects. Therefore, our results indicate that the progression of the disease proceeds with different dynamics in the structure and function of neuronal circuits from normal conditions via MCI to AD

Mirror Symmetric Bimanual Movement Priming Can Increase Corticomotor Excitability and Enhance Motor Learning

Repetitive mirror symmetric bilateral upper limb may be a suitable priming technique for upper limb rehabilitation after stroke. Here we demonstrate neurophysiological and behavioural after-effects in healthy participants after priming with 20 minutes of repetitive active-passive bimanual wrist flexion and extension in a mirror symmetric pattern with respect to the body midline (MIR) compared to an control priming condition with alternating flexion-extension (ALT). Transcranial magnetic stimulation (TMS) indicated that corticomotor excitability (CME) of the passive hemisphere remained elevated compared to baseline for at least 30 minutes after MIR but not ALT, evidenced by an increase in the size of motor evoked potentials in ECR and FCR. Short and long-latency intracortical inhibition (SICI, LICI), short afferent inhibition (SAI) and interhemispheric inhibition (IHI) were also examined using pairs of stimuli. LICI differed between patterns, with less LICI after MIR compared with ALT, and an effect of pattern on IHI, with reduced IHI in passive FCR 15 minutes after MIR compared with ALT and baseline. There was no effect of pattern on SAI or FCR H-reflex. Similarly, SICI remained unchanged after 20 minutes of MIR. We then had participants complete a timed manual dexterity motor learning task with the passive hand during, immediately after, and 24 hours after MIR or control priming. The rate of task completion was faster with MIR priming compared to control conditions. Finally, ECR and FCR MEPs were examined within a pre-movement facilitation paradigm of wrist extension before and after MIR. ECR, but not FCR, MEPs were consistently facilitated before and after MIR, demonstrating no degradation of selective muscle activation. In summary, mirror symmetric active-passive bimanual movement increases CME and can enhance motor learning without degradation of muscle selectivity. These findings rationalise the use of mirror symmetric bimanual movement as a priming modality in post-stroke upper limb rehabilitation