39 research outputs found

    Entropy and equilibrium state of free market models

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    Many recent models of trade dynamics use the simple idea of wealth exchanges among economic agents in order to obtain a stable or equilibrium distribution of wealth among the agents. In particular, a plain analogy compares the wealth in a society with the energy in a physical system, and the trade between agents to the energy exchange between molecules during collisions. In physical systems, the energy exchange among molecules leads to a state of equipartition of the energy and to an equilibrium situation where the entropy is a maximum. On the other hand, in the majority of exchange models, the system converges to a very unequal condensed state, where one or a few agents concentrate all the wealth of the society while the wide majority of agents shares zero or almost zero fraction of the wealth. So, in those economic systems a minimum entropy state is attained. We propose here an analytical model where we investigate the effects of a particular class of economic exchanges that minimize the entropy. By solving the model we discuss the conditions that can drive the system to a state of minimum entropy, as well as the mechanisms to recover a kind of equipartition of wealth

    Impacto de la condición corporal sobre la fertilidad en vacas de la provincia de Pastaza- Ecuador

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    El objetivo fue evaluar el efecto de la condición corporal sobre la fertilidad en vacas de la provincia de Pastaza-Ecuador. Se utilizaron 2434 registros reproductivos de la base de datos entre el 2009- Las variables analizadas fueron: estado reproductivo gestante y no gestante, año, raza, condición corporal (CC), celo, toro o pajuela utilizada, técnico inseminador. La muestra para el análisis estadístico de los datos se basó en tres modelos de ANOVA y un modelo mixto. El porcentaje de preñez a nivel provincial logrado con este programa de mejoramiento fue del 60 al 69%. La CC solo fue significativa para la raza Charolais mestiza, quien mostró un coeficiente de correlación lineal bajo negativo con respecto a la gestación, las otras variables celo, pajuela, técnico tampoco tuvieron diferencias estadísticas (P>0.05). Pero en el análisis del segundo modelo aplicado se encontró diferencias significativas entre el lugar (cantón) y CC (P=0.047) y entre la raza de la vaca y raza del toro (P=0.006). Se concluye que la (CC) influyó sobre la gestación dependiendo del lugar, independiente de la raza de la vaca, factor que no resultó importante en la variable reproductiva estudiada, los factores ambientales: año, cantón y CC, influyen en los niveles de gestación de la población estudiada, de los factores genéticos analizados las razas de la vaca y del padre no influyeron, solamente el factor toro fue importante en la gestación de la vaca y el factor humano resultó determinante como causa de variación en la gestación

    Rapid single-cell identification of Epstein-Barr virus-specific T-cell receptors for cellular therapy

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    BACKGROUND AND AIMS: Epstein-Barr virus (EBV) is associated with solid and hematopoietic malignancies. After allogeneic stem cell transplantation, EBV infection or reactivation represents a potentially life-threatening condition with no specific treatment available in clinical routine. In vitro expansion of naturally occurring EBV-specific T cells for adoptive transfer is time-consuming and influenced by the donor's T-cell receptor (TCR) repertoire and requires a specific memory compartment that is non-existent in seronegative individuals. The authors present highly efficient identification of EBV-specific TCRs that can be expressed on human T cells and recognize EBV-infected cells. METHODS AND RESULTS: Mononuclear cells from six stem cell grafts were expanded in vitro with three HLA-B*35:01- or four HLA-A*02:01-presented peptides derived from six EBV proteins expressed during latent and lytic infection. Epitope-specific T cells expanded on average 42-fold and were single-cell-sorted and TCRαβ-sequenced. To confirm specificity, 11 HLA-B*35:01- and six HLA-A*02:01-restricted dominant TCRs were expressed on reporter cell lines, and 16 of 17 TCRs recognized their presumed target peptides. To confirm recognition of virus-infected cells and assess their value for adoptive therapy, three selected HLA-B*35:01- and four HLA-A*02:01-restricted TCRs were expressed on human peripheral blood lymphocytes. All TCR-transduced cells recognized EBV-infected lymphoblastoid cell lines. CONCLUSIONS: The authors' approach provides sets of EBV epitope-specific TCRs in two different HLA contexts. Resulting cellular products do not require EBV-seropositive donors, can be adjusted to cell subsets of choice with exactly defined proportions of target-specific T cells, can be tracked in vivo and will help to overcome unmet clinical needs in the treatment and prophylaxis of EBV reactivation and associated malignancies

    Gamete Therapeutics: Recombinant Protein Adsorption by Sperm for Increasing Fertility via Artificial Insemination

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    A decrease in fertility can have a negative economic impact, both locally and over a broader geographical scope, and this is especially the case with regard to the cattle industry. Therefore, much interest exists in evaluating proteins that might be able to increase the fertility of sperm. Heparin binding proteins (HBPs), specifically the fertility associated antigen (FAA) and the Type-2 tissue inhibitor of metalloproteinase (TIMP-2), act to favor the capacitation and acrosome reaction and perhaps even modulate the immune system's response toward the sperm. The objective of this research was to determine the effect on fertility of adding recombinant FAA (rFAA) and recombinant TIMP-2 (rTIMP-2) to bovine semen before cryopreservation for use in an artificial insemination (AI) program in a tropical environment. For this experiment, 100 crossbred (Bos taurus x Bos indicus) heifers were selected based on their estrus cycle, body condition score (BCS), of 4 to 6 on a scale of 1 to 9, and adequate anatomical conformation evaluated by pelvic and genital (normal) measurements. Heifers were synchronized using estradiol benzoate (EB), Celosil® (PGF2α) (Shering-Plough) and a controlled internal drug release (CIDR) device was inserted that contained progesterone. Inseminations were performed in two groups at random, 50 animals per group. The control group was inseminated with conventional semen. The treatment group was inseminated with semen containing rFAA (25 µg/mL) and rTIMP-2 (25 µg/mL). In the control group a 16% pregnancy rate was obtained versus a 40% pregnancy rate for the HBP treatment group, resulting in a significant difference (P = 0.0037). Given the results herein, one may conclude that the HBPs can increase fertility and could be an option for cattle in tropical conditions; however, one needs to consider the environment, nutrition, and the genetic interaction affecting the final result in whatever reproductive program that is implemented

    ASTER, ALI and Hyperion sensors data for lithological mapping and ore minerals exploration

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    Characterizing soil hydraulic properties from Sentinel 2 and STICS crop model

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    International audienceSoil Water storage Capacity (SWC) is an important quantity in the field of hydrology and agronomy, but SWC characterization using classic method is often impossible due to soil spatial variability. In this study we take profit of the new capacities offered by the Sentinel 2 mission, which allows characterizing relevant features in vegetation dynamic linked to stresses and particularly water stresses. In addition, yield map offers an additional source of information. Both yield and vegetation development are sensitive to several factors as the water supply, nitrogen supply, crop installation quality or pest. To isolate the influence of the water supply, and therefore access parameters involved in the SWC, it is necessary to invert a crop model able to simulate the observation together with the representation of most of influencing factors. After a sensitivity analysis we have developed an inversion procedure of the STICS crop model. The procedure was tested on non-irrigated durum wheat in a Mediterranean context in southeastern France. The approach was evaluated on heterogeneous field. Soil heterogeneities are well captured by the method, but some heterogeneities interpreted as soil heterogeneities might be artefacts induced by other factors. A multiyear analysis is then necessary to get the permanent features that are most likely linked to soil propertie
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