33 research outputs found

    Remesas e inclusión financiera en municipios del Noreste de México: Un análisis espacio - temporal bayesiano

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    Este trabajo tiene por objetivo analizar la distribución espacio-temporal de las remesas en los municipios del noreste de México derivada del efecto de los servicios financieros, y por tanto, se enfoca en estudiar la relación entre el flujo de remesas y la inclusión financiera, considerando la infraestructura y red existente de servicios bancarios en los municipios de la región, al tiempo que se argumenta que la inclusión financiera puede apoyar la acumulación de recursos a través del ahorro y permitir el acceso a créditos, seguros y otro tipo de productos financieros. Los resultados muestran que la concentración de recursos en instituciones y municipios con mayor presencia de instituciones bancarias puede, evidentemente, llevar a la expansión de pequeños negocios, a la generación de ingresos derivados del desarrollo de micronegocios y a la inversión productiva especialmente en segmentos de bajos recursos y que esto se encuentra asociado a la recepción de remesas, asimismo se busca destacar la importancia de comprender las complejas interacciones entre la migración internacional, las remesas y la economía

    Effective Lagrangian Approach to Weak Radiative Decays of Heavy Hadrons

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    Motivated by the observation of the decay BˉKˉγ\bar{B}\to \bar{K}^*\gamma by CLEO, we have systematically analyzed the two-body weak radiative decays of bottom and charmed hadrons. There exist two types of weak radiative decays: One proceeds through the short-distance bsγb\to s\gamma transition and the other occurs through WW-exchange accompanied by a photon emission. Effective Lagrangians are derived for the WW-exchange bremsstrahlung processes at the quark level and then applied to various weak electromagnetic decays of heavy hadrons. Predictions for the branching ratios of Bˉ0D0γ, Λb0Σc0γ, Ξb0Ξc0γ\bar{B}^0\to D^{*0} \gamma,~\Lambda_b^0\to\Sigma_c^0\gamma,~\Xi_b^0\to \Xi_c^0\gamma and \Xi_b^0\to\xip_c^0\gamma are given. In particular, we found B(Bˉ0D0γ)0.9×106{\cal B}(\bar{B}^0 \to D^{*0}\gamma)\approx 0.9\times 10^{-6}. Order of magnitude estimates for the weak radiative decays of charmed hadrons:  D0Kˉ0γ, Λc+Σ+γ~D^0\to \bar{K}^{*0}\gamma,~\Lambda_c^+\to\Sigma^+\gamma and Ξc0Ξ0γ\Xi_c^0\to\Xi^0\gamma are also presented. Within this approach, the decay asymmetry for antitriplet to antitriplet heavy baryon weak radiative transitions is uniquely predicted by heavy quark symmetry. The electromagnetic penguin contribution to Λb0Λγ\Lambda_b^0\to\Lambda\gamma is estimated by two different methods and its branching ratio is found to be of order 1×1051\times 10^{-5}. We conclude that weak radiative decays of bottom hadrons are dominated by the short-distance bsγb\to s\gamma mechanism.Comment: 28 pages + 3 figures (not included), CLNS 94/1278, IP-ASTP-04-94. [Main changes in this revised version: (i) Sect 2 and subsection 4.1 are revised, (ii) A MIT bag method for calculating the decay rate of LambdabΛ+gammaLambda_b \to\Lambda+gamma is presented, (iii) All predictions are updated using the newly available 1994 Particle Data Group, and (iv) Appendix and subsections 3.3 and 4.4 are deleted.

    Nonleptonic Weak Decays of Bottom Baryons

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    Cabibbo-allowed two-body hadronic weak decays of bottom baryons are analyzed. Contrary to the charmed baryon sector, many channels of bottom baryon decays proceed only through the external or internal W-emission diagrams. Moreover, W-exchange is likely to be suppressed in the bottom baryon sector. Consequently, the factorization approach suffices to describe most of the Cabibbo-allowed bottom baryon decays. We use the nonrelativistic quark model to evaluate heavy-to-heavy and heavy-to-light baryon form factors at zero recoil. When applied to the heavy quark limit, the quark model results do satisfy all the constraints imposed by heavy quark symmetry. The decay rates and up-down asymmetries for bottom baryons decaying into (1/2)++P(V)(1/2)^++P(V) and (3/2)++P(V)(3/2)^++P(V) are calculated. It is found that the up-down asymmetry is negative except for Ωb(1/2)++P(V)\Omega_b \to (1/2)^++P(V) decay and for decay modes with ψ\psi' in the final state. The prediction B(ΛbJ/ψΛ)=1.6×104B(\Lambda_b \to J/\psi\Lambda)=1.6 \times 10^{-4} for Vcb=0.038|V_{cb}|=0.038 is consistent with the recent CDF measurement. We also present estimates for Ωc(3/2)++P(V)\Omega_c \to (3/2)^++P(V) decays and compare with various model calculations.Comment: 24 pages, to appear in Phys. Rev. Uncertainties with form factor q^2 dependence are discusse

    Cabibbo-allowed nonleptonic weak decays of charmed baryons

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    Cabibbo-allowed nonleptonic weak decays of charmed baryons \lamc,~\xin,~\xip and Ωc0\Omega_c^0 into an octet baryon and a pseudoscalar meson are analyzed. The nonfactorizable contributions are evaluated under pole approximation, and it turns out that the ss-wave amplitudes are dominated by the low-lying \halfm resonances, while pp-wave ones governed by the ground-state \halfp poles. The MIT bag model is employed to calculate the coupling constants, form factors and baryon matrix elements. Our conclusions are: (i) ss waves are no longer dominated by commutator terms; the current-algebra method is certainly not applicable to parity-violating amplitudes, (ii) nonfactorizable WW exchange effects are generally important; they can be comparable to and somtimes even dominate over factorizable contributions, depending on the decay modes under consideration, (iii) large-NcN_c approximation for factorizable amplitudes also works in the heavy baryon sector and it accounts for the color nonsuppression of \lamc\ri p\bar{K}^0 relative to \lamc\ri\Lambda\pi^+, (iv) a measurement of the decay rate and the sign of the α\alpha asymmetry parameter of certain proposed decay modes will help discern various models; especially the sign of α\alpha in \lamc\ri\Sigma\pi decays can be used to unambiguously differentiate recent theoretical schemes from current algebra, and (v) pp waves are the dominant contributions to the decays \lamc\ri\Xi^0 K^+ and \xin\ri\Sigma^+ K^-, but they are subject to a large cancellation; this renders present theoretical predictions on these two channels unreliable.Comment: PHYZZX, 31 pages, 3 tables, IP-ASTP-10-93, ITP-SB-93-2

    Nonleptonic Λb\Lambda_b decays to Ds(2317)D_s(2317), Ds(2460)D_s(2460) and other final states in Factorization

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    We consider nonleptonic Cabibbo--allowed Λb\Lambda_b decays in the factorization approximation. We calculate nonleptonic decays of the type ΛbΛcP \Lambda_b \to \Lambda_c P and ΛbΛcV \Lambda_b \to \Lambda_c V relative to BˉdD+P\bar{B}_d \to D^+ P and BˉdD+V\bar{B}_d \to D^+ V where we include among the pseudoscalar states(P) and the vector states(V) the newly discovered DsD_s resonances, Ds(2317)D_s(2317) and Ds(2460)D_s(2460). In the ratio of Λb\Lambda_b decays to Ds(2317)D_s(2317) and Ds(2460)D_s(2460) relative to the Bˉd\bar{B}_d decays to these states, the poorly known decay constants of Ds(2317)D_s(2317) and Ds(2460)D_s(2460) cancel leading to predictions that can shed light on the nature of these new states. In general, we predict the Λb\Lambda_b decays to be larger than the corresponding Bˉd\bar{B}_d decays and in particular we find the branching ratio for ΛbΛcDs(2460)\Lambda_b \to \Lambda_c D_s(2460) can be between four to five times the branching ratio for BˉdD+Ds(2460)\bar{B}_d \to D^+ D_s(2460). This enhancement of Λb\Lambda_b branching ratios follows primarily from the fact that more partial waves contribute in Λb\Lambda_b decays than in Bˉd\bar{B}_d decays. Our predictions are largely independent of model calculations of hadronic inputs like form factors and decay constants.Comment: 16 pages LaTe

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    La Red Internacional de Inventarios Forestales (BIOTREE-NET) en Mesoamérica: avances, retos y perspectivas futuras

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    Conservation efforts in Neotropical regions are often hindered by lack of data, since for many species there is a vacuum of information, and many species have not even been described yet. The International Network of Forest Inventory Plots (BIOTREE-NET) gathers and facilitates access to tree data from forest inventory plots in Mesoamerica, while encouraging data exchange between researchers, managers and conservationists. The information is organised and standardised into a single database that includes spatially explicit data. This article describes the scope and objectives of the network, its progress, and the challenges and future perspectives. The database includes above 50000 tree records of over 5000 species from more than 2000 plots distributed from southern Mexico through to Panama. Information is heterogeneous, both in nature and shape, as well as in the geographical coverage of inventory plots. The database has a relational structure, with 12 inter-connected tables that include information about plots, species names, dbh, and functional attributes of trees. A new system that corrects typographical errors and achieves taxonomic and nomenclatural standardization was developed using The Plant List (http://theplantlist.org/) as reference. Species distribution models have been computed for around 1700 species using different methods, and they will be publicly accessible through the web site in the future (http://portal.biotreenet.com). Although BIOTREE-NET has contributed to the development of improved species distribution models, its main potential lies, in our opinion, in studies at the community level. Finally, we emphasise the need to expand the network and encourage researchers willing to share data and to join the network and contribute to the generation of further knowledge about forest biodiversity in Neotropical regions

    El conflicto entre cristianos y musulmanes en las relaciones de sucesos : la liberación de Buda

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    Este trabajo propone el análisis de una selección de textos escritos en romance sobre la derrota turca y la toma de la ciudad de Buda en 1686, que denuncian la exultante acogida popular de la noticia de las gestas cristianas en Centroeuropa, la percepción del eterno conflicto entre Oriente y Occidente y la proyección del imaginario colectivo del siglo xvii acerca de la lucha contra los infieles.This paper offers the analysis of a selection of texts, written in Romance languages, about the Turkish defeat and the conquest of the city of Buda in 1686, which provide evidence of the popular exultation at the news of the Christian achievements in Central Europe, the perception of the eternal conflict between East and West, and the projection of the seventeenth-century collective imagination regarding the struggle against the infidel

    Charmed baryons circa 2015

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    The Tree Biodiversity Network (BIOTREE-NET): prospects for biodiversity research and conservation in the neotropics.

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    Biodiversity research and conservation efforts in the tropics are hindered by the lack of knowledge of the assemblages found there, with many species undescribed or poorly known. Our initiative, the Tree Biodiversity Network (BIOTREE-NET), aims to address this problem by assembling georeferenced data from a wide range of sources, making these data easily accessible and easily queried, and promoting data sharing. The database (GIVD ID NA-00-002) currently comprises ca. 50,000 tree records of ca. 5,000 species (230 in the IUCN Red List) from >2,000 forest plots in 11 countries. The focus is on trees because of their pivotal role in tropical forest ecosystems (which contain most of the world's biodiversity) in terms of ecosystem function, carbon storage and effects on other species. BIOTREE-NET currently focuses on southern Mexico and Central America, but we aim to expand coverage to other parts of tropical America. The database is relational, comprising 12 linked data tables. We summarise its structure and contents. Key tables contain data on forest plots (including size, location and date(s) sampled), individual trees (including diameter, when available, and both recorded and standardised species name), species (including biological traits of each species) and the researchers who collected the data. Many types of queries are facilitated and species distribution modelling is enabled. Examining the data in BIOTREE-NET to date, we found an uneven distribution of data in space and across biomes, reflecting the general state of knowledge of the tropics. More than 90% of the data were collected since 1990 and plot size varies widely, but with most less than one hectare in size. A wide range of minimum sizes is used to define a 'tree'. The database helps to identify gaps that need filling by further data collection and collation. The data can be publicly accessed through a web application at http://portal.biotreenet.com. Researchers are invited and encouraged to contribute data to BIOTREE-NET.Fundación BBV
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