La expedición británica - sueca - noruega : (1949-1952)

Fil: Corte, A. E.. Universidad Nacional de Cuyo. Facultad de Filosofía y Letra

Glaciología y ramas conexas : métodos y elementos de trabajo

Fil: Corte, A. E.. Universidad Nacional de Cuy

ACQUISITION AND EXTINCTION OF AN AVOIDANCE RESPONSE BY MILDLY RETARDED GIRLS

This study investigated the effects of some of the variables operating on the acquisition and extinction of avoidance behavior by mildly retarded adolescent girls. The subjects observed were 20 patients of Parsons State Hospital and Training Center. All the subjects were 15 years of age or older and none of them had reached her twenty-first birthday at the time that the experiment was run. They had adaptive behavior levels of I, II or III. The subjects were randomly assigned to one of two replications and to one of two experimental conditions (extinction and control). All the subjects were brought into a room and given avoidance instructions. If avoidance responding did not occur after the aversive stimulus, white noise with an intensity of 99 decibels, had been presented the experimenter prompted the subject. Prompting was continued until avoidance responding began. After 20 minutes the subjects were allowed to leave and were paid a nickel. After this first session, four more \u27avoidance sessions with no special instructions were given. After this, two more sessions were given to all the subjects with the noise lowered to an intensity of 75 decibels. In the last two sessions the now lowered noise remained on continuously for the extinction subjects, while the control subjects could still avoid it by responding. Each subject was paid a nickel at the end of each session. No replication effects of any kind were found. There were no session effects during acquisition. The extinction subjects decreased their response rate significantly more than the control subjects. The main contribution of this study is considered to be the introduction of an extinction procedure that achieves its purpose relatively fast; however, it should be more directly compared to the traditional procedure that simply stops the aversive stimulus regardless of the subjects behavior, before definite conclusions can be made

Soil Functional Ability for groundwater recharge related with Land Use and Tillage System in a dry Mediterranean climate, southern Portugal

Groundwater has capacities like storing, filtering and transforming, which allows regulates atmospheric, hydrological and nutrient cycles. For agronomists, groundwater recharge is defined as the quantity of freshwater derived from precipitation that infiltrates vertically downward from the land surface to below the root zone. At this point the water may move laterally to discharge in streams or downward to enter an aquifer. Fresh water sustains biomass growth in terrestrial ecosystems, and provides key ecological services that supports biodiversity, sequesters carbon and combats desertification. On the other hand, soils provide us services like give clean water and abundant crops. To do this, soils plays there function of “regulator” distributing water for the recharge of groundwater and for the use by plants and animals, regulating the drainage, flow and storing water. Soil functions are difficult to measure directly, so they are usually assessed by measuring soil quality indicators. The soil functional ability to provide groundwater recharge is dependent on the water flowing within soils, under natural conditions or ones affected by its exploitation. Thus Soil Functional Ability to recharge groundwater (SFAgr) and Land use are essential to study the environmental sustainability and agricultural production capability once groundwater is a key component of a healthy watershed. But it is necessary pay attention to the Tillage System and not only to Land Use because the same Land Use can be related with more or less soil mobilizations and that have a great influence on soil structure and its hydrological skills. The purpose of this study was to investigate the relationship between Soil Functional Ability for groundwater recharge (SFAgr), different Land Uses and different Tillage Systems in a Dry Mediterranean climate in Alentejo, Portugal. This will be achieved by building a SFAgr, generated with combination of four properties related to water infiltration and percolation into the soil: depth; bulk density; saturated hydraulic conductivity; and drainable porosity. The saturated hydraulic conductivity was calculated by an indirect method based on texture and drainable porosity was also calculated by an indirect method though the difference between total porosity and field capacity. Each unit Soil/ Land Use/ Tillage System was analyzed in several identical units within the same catchment. When comparing SFAgr for different Land Uses and different soils, the results show a higher dependency of the groundwater recharge ability on Soil properties than on Land Use. The highest influences on SFAgr were bulk density and saturated hydraulic conductivity and the smallers were depth and drainage porosity. Better situations are where soils have bulk density rounding 1,2 covered by Cork/Holm Oak (50%) + Pasture and the worst situation are soils with bulk density greater than 1,5 even with Cork/Holm Oak (30%) + Pasture. When comparing SFAgr only for Annual Crops at same soils but having different Tillage Systems, the results showed that in both soils studied, the SFAgr was highest when Tillage System was a conservation one than when was a traditional system. The conclusions of this study for a Dry Mediterranean Climate are: 1 – Land Use influences the Soil Functional Ability to recharge groundwater, but more important than Land Use itself is the Tillage System used; 2- Tillage Systems associated with Conservation Agriculture more specifically No Tillage Systems provide better ability to recharge groundwater in clayey soils; 3 - The more years a system of No Tillage is practiced the higher Soil Functional Ability to Groundwater Recharge is expected in clayey soils

The Regulation of Rat Liver Xanthine Oxidase CONVERSION IN VITRO OF THE ENZYME ACTIVITY FROM DEHYDROGENASE (TYPE D) TO OXIDASE (TYPE O)

Abstract The aerobic oxidation of xanthine by rat liver supernatant was greatly stimulated by the addition of methylene blue or of NAD+: the latter was reduced during the reaction. Storage of the supernatant at -20° brought about an enhancement of the xanthine oxidation rate measured without addition of cofactors. A similar "activation" was caused by prior incubation at 37° of the unfractionated liver homogenate, or of the supernatant separated after sonic disruption of the homogenate. The same effect was obtained by treatment with solvents, or by prior incubation at 37° of the supernatant in the presence of proteolytic enzymes or under anaerobic conditions. The presence of xanthine accelerated the effect of proteolytic enzymes and of anaerobiosis. Only the changes caused by anaerobiosis could be reversed by incubating the supernatant in air before the assay. The reaction rate was apparently unaffected by these treatments if activity of the enzyme was measured in the presence of methylene blue or of NAD+. The latter, however, was not reduced during the oxidation of xanthine by "activated" supernatants stored at -20° if the reaction was run in the presence of oxygen. If the reaction was in anaerobiosis, uric acid and a corresponding amount of NADH were formed by fresh, supernatant, and by supernatants activated at -20° or by prior incubation in anaerobiosis, but not by supernatant activated by trypsin. The hypothesis is formulated that most of the xanthine oxidase of rat liver supernatant is a dehydrogenase (Type D), and may be converted (activated) into an oxidase (Type O)

Multiple Glaciations of the Cordon del Plata, Mendoza, Argentina [Glaciaciones multiples del Cordon del Plata, Mendoza, Argentina]

Evidence exists for four glaciations in the Río Blanco basin west of Mendoza, Argentina. Morphology, superposition of tills, soil-profile development, loess thickness, and boulder weathering have been the techniques most useful in mapping the tills. Glaciers of Vallecitos (= Wisconsinan) age extended to 2600 m and left distinctive moraines. Tills of two preVallecitos glacier advances cover the floor of the valley from 2600 m to below 2100 m, and remnants of one of the tills extend nearly to the junction with Río Mendoza (1400 m) 13 km below the lowest Vallecitos moraines. These deposits were considered to be mudflows rather than tills by Polanski; however, the quartz sand grains examined with SEM have surface textures characteristic of glacial abrasion. The sediments, thus, are more likely glacial than mudflow deposits. One still older till caps ridges as much as 200 m above the present valley floor. Vallecitos glaciers did not smooth the walls of the wide valleys through which they flowed; the valleys had been enlarged by the larger ice tongues during one or more of the earlier glaciations. Frost shattering of the rhyolite and quartzite has altered much of the distinctive glacial valley shape, and talus lies between the valley walls and Vallecitos lateral moraines. Holocene glaciations seem to be in phase with those of the Northern Hemisphere, and the Vallecitos glaciation coincided with oxygen isotope stage 2 and the Wisconsin of North America. The next older glaciation may correlate with oxygen isotope stage 6 and the Illinoian glaciation of North America. A till that underlies it is difficult to correlate and is clearly much older, but postdates the last major uplift of the range. It may represent isotope stage 12, and the period that followed it was more moist than other interglacial ages in this area. The oldest, Los Mesones, may correlate with Mercer\u27s Greatest Glaciation of Patagonia, 1.0 to 1.2 m.y. ago. Although it is beyond the established oxygen isotope stages, a long cold period is present on the curves at this time, and it coincides with one of the glaciations of the Nebraskan-Kansan complex of North America. Resumen: Existe en la cuenca del río Blanco, al oeste de Mendoza, Argentina, evidencia por cuatro glaciaciones. Los métodos más útiles en la identificación y el trazar un mapa de los depósitos son la morfología, la superposición de los tils, el desarrollo de los perfiles de los suelos, el espesor del loess, y la meteorización de los rodados. Glaciares de la etapa Vallecitoense (= Wisconsinan/Würm) extendieron a 2600 in donde depositaron morrenas distinctivas. Los tils de los avanzes glaciales pre-Vallecitos llenan la parte baja del valle entre 2600 m y 2100 m, y remanantes de uno de ellos extiende casi a la unión de los ríos Blanco y Mendoza, 13 km más bajo que las morrenas Vallecitoenses más bajas. Estos acarreos eran considerado por Polanski como depositos de corrientes de barro más bien que til; sin embargo, las superficies de los granos de cuarzo en tamaño de arena son fracturados para que puedan ser transportados por un glaciar. Por esto, es más probable que son los acarreos depósitos de glaciares que los de corrientes de barro. Un til más antiguo cubre caballetes que están a 200 m más altos que los arroyos actuales. Los glaciares Vallecitoense no erosionaron lisos las muredes de los valles en que se deslizaron. Durante glaciaciones anteriores, lenguas de hielo más grandes que las de la última etapa han erosionado los valles. La forma distinta glaciaria se ha alterado por el astillar por congelamiento de los cuarcitas y riolitas de las pendientes, y taludes están entre los muredes y las morrenas. Las glaciaciones Holocénicas parecen en fase con elias del hemisferio del norte, y la glaciación Vallecitoense coincidió con la etapa 2 de los isótopos de oxígeno y de la glaciación Wisconsinense norteamericana. El til de la glaciación más antigua, la Río Blancoense, se correlacione con la etapa 6 de los isótopos de oxígeno y la glaciación Illinoianense de norteamerica. Hay dificultades en el correlacionar del til que está debajo de éste, el til Angosturaense. Claramente tiene más edad, pero depositó después de la ültima elevación del cordón. Se correlacione con la etapa 12. El suelo ahora enterrado que se desarrolló en la superficie de este til tiene rasgos semejantes a los de los suelos de áreas algos húmedas; en contraste, los suelos calcáreos indican que dos otros períodos interglaciales fueron más secos. El til de edad más grande de esta cuenca, Los Mesones, se correlacione con la Glaciacion Más Grande de Patagonia, descrito por Mercer, que occurrió hace 1.0 a 1.2 × 106 años. Aunque es más antigua que las etapas establecidas de isótopos de oxígeno, existe en las curvas un período largo y frío por este tiempo. También, coincide con una de las glaciaciones de complejo Nebraskan-Kansan de norteamerica

Photometry of the Oort Cloud comet C/2009 P1(Garradd): pre-perihelion observations at 5.7 and 2.5 AU

The aim of this paper is to contribute to the characterization of the general properties of the Long Period Comets (LPCs) family, and in particular to report on the dust environment of comet C/2009 P1 (Garradd). The comet was observed at two epochs pre-perihelion, at ~6 AU and at ~2.5 AU: broad-band images have been used to investigate its coma morphology and properties and to model the dust production rate. Comet C/2009 P1 (Garradd) is one of the most active and “dust producing” LPCs ever observed, even at the large heliocentric distance rh~6 AU. Its coma presents a complex morphology, with subtle structures underlying the classical fan-shaped tail, and, at rh~2.5 AU, also jet-like structures and spiralling outflows. In the reference aperture of radius ρ=5°×104 km, the R-Afρ is 3693±156 cm and 6368±412 cm, in August 2010 (rh~6 AU) and July 2011 (rh~2.5 AU), respectively. The application of a first order photometric model, under realistic assumptions on grain geometric albedo, power-law dust size distribution, phase darkening function and grain dust outflow velocity, yielded a measure of the dust production rate for the two epochs of observation of Qd=7.27×102 kg/s and Qd=1.37×103 kg/s, respectively, for a reference outflow dust velocity of vsmall=25 m/s for small (0.1–10 µm) grains and vlarge=1 m/s for large (10 µm–1 cm) grains. These results suggest that comet Garradd is one of the most active minor bodies observed in recent years, highly contributing to the continuous replenishment of the Interplanetary Dust Complex also in the outer Solar System, and pose important constraints on the mechanism(s) driving the cometary activity at large heliocentric distances

“What makes beverages products valuable to customers in the portuguese context”

The value perceived by customers remains a fundamental theme to be understood by a company. Due to its subjectivity and the possibility of, by understanding the perceived value, achieving a competitive advantage over competitors, it is a topic that is more than important and interesting to research. Considering this context, it was sought to investigate the perceived value of products where consumption is fast and constant and the market behaves competitively. Therefore, this thesis is focused on beverages in the Portuguese market, where it was desired to understand, through a qualitative approach, the opinions of the customers related to this type of product. With the purpose of understanding what makes beverages valuable to customers in Portugal, the findings of this thesis result from a systematic and continuous research process with the attribution of objectives and questions to reach reasoned and considerable conclusions for the investigated topic

Challenges and (Un)Certainties for DNAm Age Estimation in Future

Age estimation is a paramount issue in criminal, anthropological, and forensic research. Because of this, several areas of research have focused on the establishment of new approaches for age prediction, including bimolecular and anthropological methods. In recent years, DNA methylation (DNAm) has arisen as one of the hottest topics in the field. Many studies have developed age- prediction models (APMs) based on evaluation of DNAm levels of many genes in different tissue types and using different methodological approaches. However, several challenges and confounder factors should be considered before using methylation levels for age estimation in forensic contexts. To provide in-depth knowledge about DNAm age estimation (DNAm age) and to understand why it is not yet a current tool in forensic laboratories, this review encompasses the literature for the most relevant scientific works published from 2015 to 2021 to address the challenges and future directions in the field. More than 60 papers were considered focusing essentially on studies that developed models for age prediction in several sample typesinfo:eu-repo/semantics/publishedVersio

A Blood–bone–tooth model for age prediction in forensic contexts

The development of age prediction models (APMs) focusing on DNA methylation (DNAm) levels has revolutionized the forensic age estimation field. Meanwhile, the predictive ability of multi-tissue models with similar high accuracy needs to be explored. This study aimed to build multi-tissue APMs combining blood, bones and tooth samples, herein named blood–bone–tooth-APM (BBT-APM), using two different methodologies. A total of 185 and 168 bisulfite-converted DNA samples previously addressed by Sanger sequencing and SNaPshot methodologies, respectively, were considered for this study. The relationship between DNAm and age was assessed using simple and multiple linear regression models. Through the Sanger sequencing methodology, we built a BBT-APM with seven CpGs in genes ELOVL2, EDARADD, PDE4C, FHL2 and C1orf132, allowing us to obtain a Mean Absolute Deviation (MAD) between chronological and predicted ages of 6.06 years, explaining 87.8% of the variation in age. Using the SNaPshot assay, we developed a BBT-APM with three CpGs at ELOVL2, KLF14 and C1orf132 genes with a MAD of 6.49 years, explaining 84.7% of the variation in age. Our results showed the usefulness of DNAm age in forensic contexts and brought new insights into the development of multi-tissue APMs applied to blood, bone and teethinfo:eu-repo/semantics/publishedVersio