El pensamiento de Pierre Bourdieu: Apuntes para una mirada arqueológica

Pierre Bourdieu is one of the contemporary theorists most studied in different fields of social sciences social action because its principles are invited to overcome the contradictions or the classic dualisms of traditional sociology (objectivism / subjectivism, structure / agency, individual / society, matter / idea micro / macro, qualitative / quantitative) and that has been identified with overcoming determinism and sustancialismos, building more relational and procedural approaches. Its main theoretical influences come from Marxism, French structuralism, the philosophies of Martin Heidegger, Edmund Husserl, Maurice Merleau-Ponty, Raymond Aron and Ludwig Wittgenstein; including French epistemological tradition, which emphasizes non-positivism and anti-evolutionism.Pierre Bourdieu es uno de los teóricos contemporáneos de la acción social más estudiados en diferentes campos de las ciencias sociales, porque sus postulados invitan a la superación de las antinomias o los dualismos clásicos de la sociología tradicional (objetivismo/subjetivismo, estructura/agencia, individuo/sociedad, materia/idea, micro/macro, cuali/cuanti) y porque se ha identificado con la superación de los determinismos y sustancialismos, construyendo enfoques más relacionales y procesuales.Sus principales influencias teóricas provienen del marxismo, del estructuralismo francés, de las filosofías de Martin Heidegger, Edmund Husserl, Maurice Merleau-Ponty, Raymond Aron y Ludwig Wittgenstein; inclusive de la tradición epistemológica francesa, que enfatiza el no-positivismo y antievolucionismo

Economically Optimum Irrigation Patternsfor Grain Sorghum Production: Texas High Plains

Agricultural production and associated economic effects of irrigation on the Texas High Plains are seriously threatened by a rapidly declining groundwater supply and a swift upward trend in energy costs. To optimize the amount of irrigation water to be applied during specified periods of the production process, a stochastic open-loop feedback control policy was built into a grain sorghum growth simulation model. The control policy operated under the basis of constant revision of the expectations generated at every starting point for each of the production periods. If discrepancies between the expected and the realized values existed, then, based on current conditions a reevaluation of the control variable, irrigation water, was made and the decision for the first period adopted. This process continued throughout each period of the growing season. Within the stochastic policy designed, the values for the control variable were obtained by numerical search. The model was applied to estimate optimal irrigation strategies and the impact of fuel curtailments on them. Initially, optimal irrigation strategies were developed under the assumption of perfect knowledge. Under this assumption, the results indicated there was not a unique strategy to be applied at all times. The quantities of irrigation water to apply at each period depended on the initial or starting conditions. Since one of the purposes of building the model was to make it perform under stochastic or real world conditions, the assumption of complete knowledge was relaxed to consider the case where the climatic environment was unknown. As in the deterministic case, the optimal amounts of irrigation water, by period. It was also observed, that with the open-loop feedback control, the results obtained for yields did not differ substantially from those obtained in the perfect knowledge case. The discrepancies among the two cases were primarily in the optimal amount of water applied and therefore in net returns. In the stochastic case, the use of irrigation water had a mean value approximately 25 percent more than in the case of perfect knowledge. The effect of a fuel or irrigation curtailment was estimated for alternative time spans. When curtailments had a length of 10 days, there were no perceptible changes in the amount of net returns or yields, as compared to the no-curtailment case. The implication drawn was that by having frequent irrigation periods and applying optimal amounts of water, the adverse effects of 10-day curtailment periods were buffered. The cases of twenty and thirty-day periods were found to have highly negative effects on the outcomes, especially net revenues, which decreased about 50 percent (from $99 to$50) in the curtailment case of 40 - 70 days after plant emergence compared to the no-curtailment value. The effects were not only on a decreased amount of returns perceived but also on an increased spectrum of relative fluctuation (from 18 percent to 68 percent for the same situations mentioned above). It was also found that for the same time-span type of curtailments the effects were conditioned to the period in which they Occurred. However, the 20 or 30 day curtailment period might be applicable to much shorter actual fuel curtailment periods. Producers lose not only the time of fuel curtailments, but also, they must cover many acres with a limited number of wells. As a result, a 10-day fuel curtailment could easily result in a 20 to 30 day delayed irrigation. To summarize, improved irrigation distribution technology could result in increased yields and less irrigation water by simply having very close control on timing and quantity of water applied

Drilling on the Moon and Mars: Developing the Science Approach for Subsurface Exploration with Human Crews

DOMEX (Drilling on the Moon and Mars in Human Exploration) is using analog missions to develop the approach for using human crews to perform science activities on the Moon and Mars involving exploration and sampling of the subsurface. Subsurface science is an important activity that may be uniquely enabled by human crews. DOMEX provides an opportunity to plan and execute planetary mission science activities without the expense and overhead of a planetary mission. Objectives: The objective of this first in a series of DOMEX missions were to 1) explore the regional area to understand the geologic context and determine stratigraphy and geologic history of various geologic units in the area. 2) Explore for and characterize sites for deploying a deep (10 m depth) drilling system in a subsequent field season. 3) Perform GPR on candidate drill sites. 4) Select sites that represent different geological units deposited in different epochs and collect soil cores using sterile procedures for mineralogical, organic and biological analysis. 5) Operate the MUM in 3 different sites representing different geological units and soil characteristics. 6) Collect rock and soil samples of sites visited and analyze them at the habitat. Results: At mission start the crew performed a regional survey to identify major geologic units that were correlated to recognized stratigraphy and regional geologic maps. Several candidate drill sites were identified. During the rest of the mission, successful GPR surveys were conducted in four locations. Soil cores were collected in 5 locations representing soils from 4 different geologic units, to depths up to 1m. Soil cores from two locations were analyzed with PCR in the laboratory. The remainder were reserved for subsequent analysis. XRD analysis was performed in the habitat and in the field on 39 samples, to assist with sample characterization, conservation, and archiving. MUM was deployed at 3 field locations and 1 test location (outside the habitat) where it operated autonomously for 2-4 hours at each site. Depths achieved ranged from 15 to 70 cm depending on the soil compressive strength and the presence and depth of subsurface indurated layers. Subsurface samples weighing 0.5 to 1 g were collected at the deepest depth encountered at each of the sites using the MUM automated sample collection system, and subsequently analyzed with XRD. Downhole inspection of holes produced by MUM with the Raman spectrometer was acquired on two of the holes and spectral features associated with selenite were identified in specific soil layers. Previously unreported fossilized remains of vertebrate fauna from the Jurassic era were discovered during our mission. Analysis of mineral biomarkers associated with this discovery are underway

Biosynthesis of Silver Nanoparticles Using Chenopodium ambrosioides

Biosynthesis of silver nanoparticles (AgNPs) was achieved using extract of Chenopodium ambrosioides as a reducer and coating agent at room temperature (25°C). Two molar solutions of AgNO3 (1 mM and 10 mM) and five extract volumes (0.5, 1, 2, 3, and 5 mL) were used to assess quantity, shape, and size of the particles. The UV-Vis spectra gave surface plasmon resonance at 434–436 nm of the NPs synthesized with AgNO3 10 mM and all extract volumes tested, showing a direct relationship between extract volumes and quantity of particles formed. In contrast, the concentration of silver ions was related negatively to particle size. The smallest (4.9 ± 3.4 nm) particles were obtained with 1 mL of extract in AgNO3 10 mM and the larger amount of particles were obtained with 2 mL and 5 mL of extract. TEM study indicated that the particles were polycrystalline and randomly oriented with a silver structure face centered cubic (fcc) and fourier transform infrared spectroscopy (FTIR) indicated that disappearance of the –OH group band after bioreduction evidences its role in reducing silver ions

The Impact of Energy Shortage and Cost on Irrigation for the High Plains and Trans Pecos Regions of Texas

The High Plains and Trans Pecos regions of Texas are semi-arid crop production regions located in the western part of the state. Relatively low levels of rainfall are supplemented by irrigation from groundwater supplies. These regions produced 51 percent of the cotton, 42 percent of the grain sorghum, and 48 percent of the wheat produced in Texas in 1974 (Texas Crop and Livestock Reporting Service). Considering only irrigated production these percentages were 75, 85, and 91 percent of Texas irrigated crop production for cotton, grain sorghum and wheat respectively. The importance of the High Plains and Trans Pecos regions to Texas crop production are not limited to these three crops, however, these statistics do serve to illustrate the significance of these regions in the Texas agricultural economy. While it is easily seen that the majority of irrigated production (for the crops mentioned) in Texas occurs in these regions, it should be noted that the importance of irrigation in the High Plains and Trans Pecos regional economies is much greater than these statistics show. On the High Plains 86 percent of the cotton, 90 percent of the grain sorghum, and 75 percent of the wheat produced in 1974 was harvested from irrigated acreage. Rainfall is somewhat less in the Trans Pecos region and 100 percent of the production of these crops was under irrigation (Texas Crop and Livestock Reporting Service). More than 60 percent of the value of agricultural crops in Texas is produced on irrigated land (Knutson, et.al.). Thus, the crop production of these regions is vitally important to the Texas and respective regional economies. Crop yields are heavily dependent on groundwater irrigation and extremely sensitive to any factor which may affect the availability or cost of irrigation water. Availability and price of fuel used in pumping groundwater are the critical factors which directly affect the availability and cost of irrigation water. About 39 percent of the energy used in Texas agriculture in 1973 was utilized in pumping water, compared to 18 percent used in machinery operations. Of this irrigation fuel, 76 percent was natural gas, the majority of which was consumed in the High Plains (Coble and LePori). Current supplies and reserves of natural gas have reached critically low levels in recent years and producers in the High Plains and Trans Pecos regions are faced with possible curtailments of, and certain price increases for their irrigation fuel (Patton and Lacewell). The threat of possible curtailment of fuel supplies during the irrigation season imposes greatly increased risk to irrigated crop production since curtailment of natural gas supplies during a critical water use period would significantly reduce yields (Lacewell). This threat would also increase financial risk and restrict availability of credit. Continued price increases for natural gas will increase costs of pumping irrigation water and hence the costs of irrigated crop production (Patton and Lacewell). The Ogalalla aquifer underlying the High Plains and many of the alluvium aquifers underlying the Trans Pecos are exhaustible; i.e., there is a negligible recharge from percolation and other sources. Therefore, even with unchanged natural gas prices, these groundwater supplies are being "economically" exhausted over time as pumping depth increases. Increases in fuel prices will lead to reduced groundwater pumpage and result in less groundwater being economically recoverable. Although life of the physical supply will be exhausted, a greater quantity of groundwater will be economically unrecoverable for irrigation without significant product price increases

Partial transplantation of trachea with preservation of vascular supply: experimental study with and without immunosuppression in animal models

Introducción. La intubación traqueal prolongada puede causar estenosis. En lesiones extensas, se han realizado trasplantes o colocación de prótesis sin buenos resultados. El trasplante evoluciona frecuentemente con necrosis, retraso de la cicatrización, estenosis e isquemia. En este trabajo se realizó el trasplante de un segmento anterior de la pared traqueal, para preservar el suministro vascular del tejido que permita ampliar la luz traqueal y supere los problemas derivados del trasplante completo o de la inserción de prótesis. Objetivo. Evaluar la viabilidad, los cambios histológicos macroscópicos y microscópicos en trasplante alógénico de un parche anterior de tráquea, en dos grupos de conejos, con y sin inmunosupresión. Métodos. Estudio experimental, prospectivo, randomizado y controlado. Se utilizaron 15 conejos de cepas exocriadas. En 5 se realizó autotrasplante para estandarizar la técnica quirúrgica. En 10 se realizó alotrasplante de la pared anterior de la tráquea, a 5 de los cuales se les administró ciclosporina. Se hizo la eutanasia al día 15 del postoperatorio, para estudio macro y microscópico. Resultados. Todos los conejos evolucionaron satisfactoriamente. No hubo diferencia significativa entre los que recibieron inmunosupresión y los que no la recibieron, cuando se evaluó la pérdida del epitelio, tejido de granulación, infiltración linfocitaria y fibroproliferación. Sí hubo oclusión luminal debido a causas inflamatorias. Al evaluar hialinosis vascular, estrechez vascular, endotelitis y linfangiectasias no hubo diferencia significativa, ninguno presentó necrosis tisular. Se encontraron numerosos capilares permeables en el segmento trasplantado y conservación del epitelio. Conclusiones. El trasplante segmentario de pared anterior de tráquea permitió ampliar la luz traqueal con preservación vascular del injerto y buena viabilidad, macro y microscópica. La evolución postquirúrgica fue buena en ambos grupos.Introduction. Prolonged tracheal intubation can cause stenosis. In extensive lesions, they have performed transplants or prosthesis placement without good results. Transplantation frequently evolves with necrosis, delayed healing, and ischemia. The anterior segment of the tracheal wall was transplanted to preserve the vascular supply of the trachea. Objectives. Verify that the transplant of a previous patch of the trachea, allows to expand the tracheal lumen in its anterior part and overcome the problems derived from the complete transplant or the insertion of prosthesis and evaluate the viability, macroscopic and microscopic changes of the transplant in two groups of rabbits, one of which will receive treatment with immunosuppressants. Methods. Experimental, prospective, randomized and controlled study. We used 15 rabbits of exocriated strains. In 5, autotransplantation was performed to standardize the surgical technique. In 10, an alotransplant of the anterior wall of the trachea was performed, 5 of which were administered ciclosporin. Euthanasia was performed 15 days postoperatively, for macro and microscopic study. Results. All rabbits evolved satisfactorily. There was no significant difference between those who received immunosuppression and those who did not receive it, when loss of epithelium, granulation tissue, lymphocyte infiltration and fibroproliferation was evaluated. If there was luminal occlusion due to inflammatory causes. When evaluating vascular hyalinosis, vascular stricture, endothelitis and lymphangiectasis there was no significant difference. In none was tissue necrosis found. There were numerous permeable capillaries in the transplanted segment and conservation of the epithelium. Conclusions. The segmental transplantation of the anterior wall of the trachea allowed to enlarge the tracheal lumen with vascular preservation of the graft and good viability, macro and microscopic. Postoperative evolution was good in both groups

Study of the Performance of the Organic Extracts of Chenopodium ambrosioides

There are many ways to obtain metal nanoparticles: biological, physical, and chemical ways and combinations of these approaches. Synthesis assisted with plant extracts has been widely documented. However, one issue that is under discussion refers to the metabolites responsible for reduction and stabilization that confine nanoparticle growth and prevent coalescence between nanoparticles in order to avoid agglomeration/precipitation. In this study, Ag nanoparticles were synthesized using organic extracts of Chenopodium ambrosioides with different polarities (hexane, dichloromethane, and methanol). Each extract was phytochemically characterized to identify the nature of the metabolites responsible for nanoparticle formation. With methanol extract, the compounds responsible for reducing and stabilizing silver nanoparticle were associated with the presence of phenolic compounds (flavonoids and tannins), while, with dichloromethane and hexane extracts, the responsible compounds were mainly terpenoids. Large part of the reducing activity of secondary metabolites in C. ambrosioides is closely related to compounds with antioxidant capacity, such as phenolic compounds (flavone glycoside and isorhamnetin), which are the main constituents of the methanol extracts. Otherwise, terpenoids (trans-diol, α-terpineol, monoterpene hydroperoxides, and apiole) are the central metabolites present in dichloromethane and hexane extracts

Monocytes regulate the mechanism of T-cell death by inducing Fas-mediated apoptosis during bacterial infection.

Monocytes and T-cells are critical to the host response to acute bacterial infection but monocytes are primarily viewed as amplifying the inflammatory signal. The mechanisms of cell death regulating T-cell numbers at sites of infection are incompletely characterized. T-cell death in cultures of peripheral blood mononuclear cells (PBMC) showed 'classic' features of apoptosis following exposure to pneumococci. Conversely, purified CD3(+) T-cells cultured with pneumococci demonstrated necrosis with membrane permeabilization. The death of purified CD3(+) T-cells was not inhibited by necrostatin, but required the bacterial toxin pneumolysin. Apoptosis of CD3(+) T-cells in PBMC cultures required 'classical' CD14(+) monocytes, which enhanced T-cell activation. CD3(+) T-cell death was enhanced in HIV-seropositive individuals. Monocyte-mediated CD3(+) T-cell apoptotic death was Fas-dependent both in vitro and in vivo. In the early stages of the T-cell dependent host response to pneumococci reduced Fas ligand mediated T-cell apoptosis was associated with decreased bacterial clearance in the lung and increased bacteremia. In summary monocytes converted pathogen-associated necrosis into Fas-dependent apoptosis and regulated levels of activated T-cells at sites of acute bacterial infection. These changes were associated with enhanced bacterial clearance in the lung and reduced levels of invasive pneumococcal disease