Estrategias de mitigación de emisiones de gases de efecto invernadero en sistemas ganaderos bovinos extensivos del sur de San Luis, Argentina. Estudio de casos

La ganadería bovina es una de las principales fuentes de emisiones antropogénicas de gases de efecto invernadero (GEI). A nivel internacional, regional y nacional existe una gran diversidad de estudios relacionados con la búsqueda de estrategias de mitigación de esos gases. El objetivo de este trabajo fue analizar el efecto de la aplicación de tecnologías estratégicas sobre las emisiones de GEI en sistemas productivos ganaderos típicos de la región sur de San Luis. Para ello se analizaron 6 casos de estudios en sus características actuales (SPA) y se plantearon y simularon dos propuestas mejoradoras de sus sistemas productivos (SPM1 y SPM2), se estimaron emisiones de CH4 por fermentación entérica y N2O de suelos gestionados. Se caracterizaron las emisiones y se realizó una comparación de emisiones de GEI de los sistemas entre sus tres estados (SPA, SPM1 y SPM2) a través de un ANOVA. Las “emisiones por ternero” fueron significativamente superiores (P<0,001) en el SPA que en los SPM1 y SPM2 emitiendo un 33% y un 36% menos de emisiones que el SPA. En el caso de las “emisiones por kg de peso vivo vendido” las emisiones fueron significativamente superiores en el SPA respecto al SPM2 emitiendo este un 25% menos. La aplicación de nuevas tecnologías no solamente disminuye las emisiones, sino que mejora la producción de esos sistemas. Por lo que, los resultados demuestran que la aplicación de prácticas de mejora en los sistemas de producción (ajuste de carga animal, reordenamiento del rodeo, manejo del pasto, sanidad animal, división de potreros) tienen un considerable potencial para mitigar las emisiones de GEI en estos sistemas. Cattle farming are one of the main sources of anthropogenic emissions of greenhouse gases (GHG). At the international, regional and national levels, there is a great diversity of studies related to the search for mitigation strategies for these gases. The objective of this work was to analyze the effect of the application of strategic technologies on GHG emissions in typical livestock production systems of the southern region of San Luis. To do this, six case studies were analyzed in their current characteristics (SPA) and two proposals were raised to improve their production systems (SPM1 and SPM2), estimating emissions by CH4 through enteric fermentation and N2O of the managed soils. The GHG emissions were characterized and comparison was made of the systems between their three states (SPA, SPM1 and SPM2) was conducted through an ANOVA. The “emissions per calf” were significantly higher (P &lt;0.001) in the SPA than in the SPM1 and SPM2, emitting 33% and 36% less emissions than the SPA. In the case of “emissions per kg of live weight sold”, emissions were significantly higher in the SPA compared to SPM2, emitting 25% less. The application of technologies not only reduce emissions but also improve the production of these systems. Therefore, the results show that the application of management practices in the production systems (animal load adjustment, herd rearrangement, pasture management, animal health, division of paddocks) have considerable potential to mitigate emissions of GHG in these systems

Quantum versus Semiclassical Description of Selftrapping: Anharmonic Effects

Selftrapping has been traditionally studied on the assumption that quasiparticles interact with harmonic phonons and that this interaction is linear in the displacement of the phonon. To complement recent semiclassical studies of anharmonicity and nonlinearity in this context, we present below a fully quantum mechanical analysis of a two-site system, where the oscillator is described by a tunably anharmonic potential, with a square well with infinite walls and the harmonic potential as its extreme limits, and wherein the interaction is nonlinear in the oscillator displacement. We find that even highly anharmonic polarons behave similar to their harmonic counterparts in that selftrapping is preserved for long times in the limit of strong coupling, and that the polaronic tunneling time scale depends exponentially on the polaron binding energy. Further, in agreement, with earlier results related to harmonic polarons, the semiclassical approximation agrees with the full quantum result in the massive oscillator limit of small oscillator frequency and strong quasiparticle-oscillator coupling.Comment: 10 pages, 6 figures, to appear in Phys. Rev.

Properties of LZS/nanoAl2O3 glass-ceramic composites

[EN] The LZS glass-ceramic (19.58 Li2O center dot 11.10ZrO(2)center dot 69.32SiO(2)) have a high coefficient thermal expansion (CTE) which can be a limitation in some applications. The addition of alumina in a LZS glass-ceramic matrix is able to reduce the CTE significantly. This happens because of the alumina affinity with respect to lithium silicates to form beta-spodumene (LiAlSi2O6), a crystalline phase having a CTE nearly zero (0.9 x 10(-6) degrees C-1).In this work, (1-5 vol%) Al2O3 nanoparticles (13 nm) were added to a LZS (3.5 mu m) glass-ceramic matrix to prepare composites with the main goal of evaluation the influence of Al2O3 on their mechanical, thermal and electrical properties. Each composition was wet homogenized and then dried at 110 degrees C for 48 h for disaggregation. The composites, sintered at 900 degrees C for 30 min, with relative densities between 92% and 98%, showed zircon and beta-spodumene as main crystalline phases. The incorporation of increasing additions of nanosized alumina progressively decreases the final density. This makes the properties to slightly decrease, also. The Young's modulus significantly decreases from 111 to 78 GPa of hardness due to the exponential variation with porosity, but the changes of toughness and hardness are much lower. The electrical conductivity was maintained within +/- 10-7 S. cm(-1), and the dielectric constant ranged from 5 to 6 for all compositions. Thermal conductivity ranged around 4.2 to 3.5 W/mK. (C) 2017 Elsevier B.V. All rights reserved.This work has been supported by CAPES in the frame of the International Cooperation Program Science without Borders for Special Visiting Researcher PVE (MEC/MCTI/CAPES/CNPq/FAPs/ No 71/2013), Project No A011/2013 (Brazil) and CNPq (National Council for Scientific and Technological Development, Brazil). This work has been also supported by Ministerio de Economia y Cornpetitividad and FEDER Funds under grant No MAT2016-67586-C3-R and grant ENE2013-49111-C2-1-R. A. Borrell acknowledges the MINECO for her Juan de la Cierva-Incorporacion contract (IJCI-2014-19839).Arcaro, S.; Moreno, B.; Chinarro, E.; Salvador Moya, MD.; Borrell Tomás, MA.; Nieto, M.; Moreno, R.... (2017). Properties of LZS/nanoAl2O3 glass-ceramic composites. Journal of Alloys and Compounds. 710:567-574. https://doi.org/10.1016/j.jallcom.2017.03.299S56757471

Path and Path Deviation Equations for p-branes

Path and path deviation equations for neutral, charged, spinning and spinning charged test particles, using a modified Bazanski Lagrangian, are derived. We extend this approach to strings and branes. We show how the Bazanski Lagrangian for charged point particles and charged branes arises `a la Kaluza-Klein from the Bazanski Lagrangian in 5-dimensions.Comment: 13 pages, LaTeX fil

Coupled Dipole Method Determination of the Electromagnetic Force on a Particle over a Flat Dielectric Substrate

We present a theory to compute the force due to light upon a particle on a dielectric plane by the Coupled Dipole Method (CDM). We show that, with this procedure, two equivalent ways of analysis are possible, both based on Maxwell's stress tensor. The interest in using this method is that the nature and size or shape of the object, can be arbitrary. Even more, the presence of a substrate can be incorporated. To validate our theory, we present an analytical expression of the force due to the light acting on a particle either in presence, or not, of a surface. The plane wave illuminating the sphere can be either propagating or evanescent. Both two and three dimensional calculations are studied.Comment: 10 pages, 8 figures and 3 table

Los sistemas ganaderos bovinos y los gases de efecto invernadero en el sur de San Luis

Argentina, con su gran variedad de suelos y clima, tiene una economía basada fundamentalmente en la producción agropecuaria por lo que no es ajena a los efectos debido al cambio climático. En orden de importancia, las emisiones de metano (CH4) ligada a las producciones agro-ganaderas, a escala nacional, es una de las contribuyentes a la emisión de gases de efecto invernadero (GEI) (SAGyP, 2007). Estas emisiones se producen debido a diversos factores, entre otros, al tipo de tecnología de manejo que se aplique. El objetivo de este trabajo fue analizar las estimaciones de las emisiones de metano (CH4) y óxido nitroso (N2O) en los sistemas ganaderos bovinos del sur del departamento Capital de la provincia de San Luis

Insights into the catalytic production of hydrogen from propane in the presence of oxygen: cooperative presence of vanadium and gold catalysts

[EN] H-2 and propylene can be obtained from propane and oxygen in defect using appropriate catalysts. Meanwhile propylene is formed from propane via oxidative or non-oxidative dehydrogenation, molecular hydrogen can be obtained from several reactions such as propane dehydrogenation, coke formation and water gas shift. It has been observed that a gold catalyst hardly activates propane and no H-2 was detected, whereas using vanadium oxide a relatively high concentration of propylene and H-2 was obtained. Interestingly, the simultaneous use of vanadium oxide and gold has meant a higher hydrogen production, higher in a 40% than that of the catalyst containing only vanadium oxide. This performance has been. related to the capacity of gold to activate CO in the water gas shift reaction. (C) 2015 Elsevier B.V. All rights reserved.The authors would like to acknowledge the DGICYT in Spain (CTQ2012-37925-C03-1, CTQ2012-37925-C03-2 and CTQ2012-37984-C02-01) for financial support We also thank the University of Valencia and SCSIE-UV for assistance. J.M. Lopez would also like to thank Spanish MICINN and CSIC for funding his Ramon y Cajal contract (RYC-2009-04483).Garcia, T.; Lopez, JM.; López Nieto, JM.; Sanchis, R.; Dejoz, A.; Vazquez, MI.; Solsona, B. (2015). Insights into the catalytic production of hydrogen from propane in the presence of oxygen: cooperative presence of vanadium and gold catalysts. Fuel Processing Technology. 134:290-296. https://doi.org/10.1016/j.fuproc.2015.02.012S29029613

Expert panel consensus recommendations for diagnosis and treatment of secondary osteoporosis in children

Background: Osteoporosis incidence in children is increasing due to the increased survival rate of patients suffering from chronic diseases and the increased use of drugs that can damage bones. Recent changes made to the definition of childhood osteoporosis, along with the lack of guidelines or national consensuses regarding its diagnosis and treatment, have resulted in a wide variability in the approaches used to treat this disease. For these reasons, the Osteogenesis Imperfecta and Childhood Osteoporosis Working Group of the Spanish Society of Pediatric Rheumatology has sounded the need for developing guidelines to standardize clinical practice with regard to this pathology. Methods: An expert panel comprised of 6 pediatricians and 5 rheumatologists carried out a qualitative literature review and provided recommendations based on evidence, when that was available, or on their own experience. The level of evidence was determined for each section using the Oxford Centre for Evidence-based Medicine (CEBM) system. A Delphi survey was conducted for those recommendations with an evidence level of IV or V. This survey was sent to all members of the SERPE. All recommendations that had a level of agreement higher or equal to 70% were included. Results: Fifty-one recommendations, categorized into eight sections, were obtained. Twenty-four of them presented an evidence level 4 or 5, and therefore a Delphi survey was conducted. This was submitted electronically and received a response rate of 40%. All recommendations submitted to the Delphi round obtained a level of agreement of 70% or higher and were therefore accepted. Conclusion: In summary, we present herein guidelines for the prevention, diagnosis and treatment of secondary childhood osteoporosis based on the available evidence and expert clinical experience. We believe it can serve as a useful tool that will contribute to the standardization of clinical practice for this pathology. Prophylactic measures, early diagnosis and a proper therapeutic approach are essential to improving bone health, not only in children and adolescents, but also in the adults they will become in the future

Phase I clinical trial in healthy adults of a nasal vaccine candidate containing recombinant hepatitis B surface and core antigens

SummaryBackgroundThe nasal vaccine candidate (NASVAC), comprising hepatitis B virus (HBV) surface (HBsAg) and core antigens (HBcAg), has been shown to be highly immunogenic in animal models.MethodsA phase I double-blinded, placebo-controlled randomized clinical trial was carried out in 19 healthy male adults with no serologic markers of immunity/infection to HBV. This study was aimed at exploring the safety and immunogenic profile of nasal co-administration of both HBV recombinant antigens. The trial was performed according to Good Clinical Practice guidelines. Participants ranged in age from 18 to 45 years and were randomly allocated to receive a mixture of 50μg HBsAg and 50μg HBcAg or 0.9% physiologic saline solution, as a placebo, via nasal spray in a five-dose schedule at 0, 7, 15, 30, and 60 days. A total volume of 0.5ml was administered in two dosages of 125μl per nostril. Adverse events were actively recorded 1h, 6h, 12h, 24h, 48h, 72h, 7 days and 30 days after each dose. Anti-HBs and anti-HBc titers were evaluated using corresponding ELISA kits at days 30 and 90.ResultsThe vaccine candidate was safe and well tolerated. Adverse reactions included sneezing (34.1%), rhinorrhea (12.2%), nasal stuffiness (9.8%), palate itching (9.8%), headache (9.8%), and general malaise (7.3%). These reactions were all self-limiting and mild in intensity. No severe or unexpected events were recorded during the trial. The vaccine elicited anti-HBc seroconversion in 100% of subjects as early as day 30 of the immunization schedule, while a seroprotective anti-HBs titer (≥10IU/l) was at a maximum at day 90 (75%). All subjects in the placebo group remained seronegative during the trial.ConclusionThe HBsAg–HBcAg vaccine candidate was safe, well tolerated and immunogenic in this phase I study in healthy adults. To our knowledge, this is the first demonstration of safety and immunogenicity for a nasal vaccine candidate comprising HBV antigens

Determinants and Differences in Satisfaction with the Inhaler Among Patients with Asthma or COPD

Satisfaction with the inhaler is an important determinant of treatment adherence in patients with asthma and chronic obstructive pulmonary disease (COPD). However, few studies have compared these 2 groups to identify the factors associated with satisfaction with the inhaler. To assess and compare satisfaction with the inhaler in patients with asthma or COPD and to determine the variables associated with high inhaler satisfaction. A multicenter, cross-sectional study of 816 patients (406 with asthma and 410 with COPD) was conducted. Satisfaction was assessed with the Feeling of Satisfaction with Inhaler (FSI-10) questionnaire. All participants completed the Test of Adherence to Inhalers and either the Asthma Control Test (ACT) or the COPD Assessment Test (CAT). Overall, the asthma group was significantly more satisfied with the inhaler (mean [standard deviation] FSI-10 scores: 44.1 [6.5] vs 42.0 [7.7]; P <.001) and more satisfied on most (7 of 10; 70%) items. Patients with asthma were significantly more satisfied with the inhaler regardless of the adherence level or the type of nonadherence pattern. Younger age, good disease control (ACT ≥20 or CAT ≤10), previous inhaler training, and absence of unwitting nonadherence were all independently and significantly associated with high inhaler satisfaction. Age, disease control, and training in inhalation technique all play a more significant role than the specific diagnosis in explaining satisfaction with the device in patients with asthma and COPD. These findings underscore the need to provide better training and more active monitoring of the inhalation technique to improve patient satisfaction, treatment adherence, and clinical outcomes