5,399 research outputs found
The Maize Seed Industries of Brazil and Mexico: Past Performance, Current Issues, and Future Prospects
This paper describes results of a study of the main factors affecting the development of the maize seed industries in Brazil and Mexico (and, by extension, other developing countries). The authors develop a framework that researchers and policy makers can use to evaluate seed industry performance in developing countries. This framework is used to analyze the seed industries of Brazil and Mexico, where very different sets of circumstances influence seed industry development, efficiency, and structure. The analysis gives special attention to the different maize breeding strategies pursued by the public and private sectors, measures of industry competitiveness and efficiency, and the trade-offs involved in developing and producing different kinds of maize seed, particularly improved open-pollinated maize varieties versus different types of hybrids. The authors identify key seed industry issues for researchers, administrators of national maize programs, and agricultural policy makers in developing countries, especially issues related to the appropriate roles for public and private organizations in maize seed industries in the developing world.Crop Production/Industries,
An empirical contribution to development theory: a covariance structure model for development as freedom
This Thesis examines the empirical validity of Sen’s development theory. In his seminal work “Development as Freedom” Sen postulated a theoretical conceptualization of development which constitutes a paradigm shift towards a fundamental understanding of the determinants and causal relationships that explain development. A deconstruction of Sen’s development theory leads to five core tenets on which his theoretical conceptualization rests. These five pillars are translated onto testable hypothesis which are incorporated into a 2nd order recursive Covariance Structure Model (CSM) that allows scientific examination through hypothesis testing. Sen’s hypothesized core tenets are as follows: 1. Development is seen as an integrated multi-dimensional construct. Evaluative assessments of development require a broadening of the informational basis, and cannot be viewed only on the basis of one sole indicator (i.e. income per capita or gross domestic product). 2. Instrumental freedoms (i.e institutional structure) directly enhance substantive freedoms (i.e societal capabilities). 3. Substantive freedoms are derived from five different types of instrumental freedoms. 4. The expansion of freedoms is the primary end of development. 5. The existence of interlinkages between different kinds of instrumental freedoms. A database comprising 5 measured variables in the economic dimension, 5 in the social dimension, and 6 in the political dimension, for 154 countries (for all levels of income) for the average period from 1990 - 1994 was put together. The resulting empirical covariance matrix from the data was subjected to scientific hypothesis testing against the CSM. The results provide strong empirical evidence in support of Sen\u27s development as freedom theory. The clear implication is that Sen\u27s paradigm shift in development theory calls for a total rethinking on the socio-economic front of policy making, and that, once and for all, scholars in long-term growth and in political economy, policy makers, and world financial institutions alike should seriously consider an in-depth review, if not totally abandon, the unidimensional dominant perspective that for far too long now has negatively impacted and slowed down economic growth around the world
Probing the " from " supersymmetric standard model with displaced multileptons from the decay of a Higgs boson at the LHC
The " from " supersymmetric standard model (SSM) cures the
-problem and concurrently reproduces measured neutrino data by using a set
of usual right-handed neutrino superfields. Recently, the LHC has revealed the
first scalar boson which naturally makes it tempting to test SSM in the
light of this new discovery. We show that this new scalar while decaying to a
pair of unstable long-lived neutralinos, can lead to a distinct signal with
non-prompt multileptons. With concomitant collider analysis we show that this
signal provides an unmistakable signature of the model, pronounced with light
neutralinos. Evidence of this signal is well envisaged with sophisticated
displaced vertex analysis, which deserves experimental attention.Comment: 5 pages, 3 figures, title, text, abstract and references modifie
Hunting physics beyond the standard model with unusual and decays
Nonstandard on-shell decays of and bosons are possible within the
framework of extended supersymmetric models, i.e., with singlet states and/or
new couplings compared to the minimal supersymmetric standard model. These
modes are typically encountered in regions of the parameter space with light
singlet-like scalars, pseudoscalars, and neutralinos. In this letter we
emphasize how these states can lead to novel signals at colliders from - or
-boson decays with prompt or displaced multileptons/tau
jets/jets/photons in the final states. These new modes would give distinct
evidence of new physics even when direct searches remain unsuccessful. We
discuss the possibilities of probing these new signals using the existing LHC
run-I data set. We also address the same in the context of the LHC run-II, as
well as for the future colliders. We exemplify our observations with the "
from " supersymmetric standard model, where three generations of
right-handed neutrino superfields are used to solve shortcomings of the minimal
supersymmetric standard model. We also extend our discussion for other variants
of supersymmetric models that can accommodate similar signatures.Comment: New discussions and references added, 8 pages, 1 figure, matches with
the published version in Phys. Rev.
Appellation of Origin Status and Economic Development: A Case Study of the Mezcal Industry
Mezcal is an alcoholic beverage produced only in selected regions of Mexico under appellation of origin status from the Word Intellectual Property Organization. While it has been produced in Mexico for many centuries, mezcal’s appellation of origin was only granted in 1995. Therefore efforts to produce and market it as a premium product have a relatively short history. This case study examines developments in the production and marketing of this unique product, and the activities of the marketing cooperative El Tecuán in Guerrero State in this process.mezcal, Mexico, appellation, marketing, cooperative, Community/Rural/Urban Development, Marketing,
The top-quark mass in SU(5)xU(1) supergravity
We show that the currently experimentally preferred values of the top-quark
mass (\ie, 130\lsim m_t\lsim180\GeV) are naturally understood in the context
of string models, where the top-quark Yukawa coupling at the string scale is
generically given by , with the unified gauge
coupling. A detailed study of the Yukawa sector of
supergravity shows that the ratio of the bottom-quark to tau-lepton Yukawa
couplings at the string scale is required to be in the range
0.7\lsim\lambda_b/\lambda_\tau\lsim1, depending on the values of and
. This result is consistent with symmetry, which does
{\em not} require the equality of these Yukawa couplings in the unbroken
symmetry phase of the theory. As a means of possibly predicting the value of
, we propose a procedure whereby the size of the allowed parameter space
is determined as a function of , since all sparticle and Higgs-boson
masses and couplings depend non-trivially on . At present, no significant
preference for particular values of in supergravity is
observed, except that high-precision LEP data requires m_t\lsim180\GeV.Comment: latex, 10 pages, 4 figures (included), CERN-TH.7138/94,
CTP-TAMU-05/9
Characterization of HIV-1 RNA forms in the plasma of patients undergoing successful HAART
An assay to characterize plasma human immunodeficiency virus 1 (HIV-1) sequences for patients with low viral loads was developed by combining the selective binding of anti-CD44 MicroBeads with a nested RT-PCR targeting the env C2V4 region. Sequences were obtained from 10 of 20 HIV+ patients who had viral loads below 48 copies/ml. Sequences derived from plasma were compared to those from CD14+ CD16 +monocytes and CD4+ T cells. The plasma sequences were most closely related to those amplified from monocytes, suggesting that during successful antiretroviral therapy, the predominant plasma virus originates from myeloid cells. By characterizing HIV-1 RNA sequences from 8 ml of plasma while avoiding multiple steps, which can lead to contamination and deterioration, this method can help elucidate the viral forms in patients with therapeutically suppressed HIV-1. Understanding the source of residual viremia is crucial in developing approaches for viral eradication
Quantum Flows for Secret Key Distribution
Despite the unconditionally secure theory of quantum key distribution (QKD), several attacks have been successfully implemented against commercial QKD systems. Those systems have exhibited some flaws, as the secret key rate of corresponding protocols remains unaltered, while the eavesdropper obtains the entire secret key. We propose a new theoretical approach called quantum flows to be able to detect the eavesdropping activity in the channel without requiring additional optical components different from the BB84 protocol because the system can be implemented as a high software module. In this approach, the transmitter interleaves pairs of quantum states, referred to here as parallel and orthogonal (non-orthogonal) states, while the receiver uses active basis selection
Optimizing Power Consumption of Freight Railroad Bearings Using Laboratory Experimental Data
Based on projected freight truck fuel efficiency, freight railroad and equipment suppliers need to identify, evaluate and implement technologies and/or operating practices to maintain traditional railroad economic competitiveness. The railway industry uses systems that record the total energy efficiency of a train but not energy efficiency or consumption by components. Lowering the energy consumption of certain train components will result in an increase in its overall energy efficiency, which will yield cost benefits for all the stakeholders. One component of interest is the railroad bearing whose power consumption varies depending on several factors that include railcar load, train speed, condition of bearing whether it is healthy or defective, and type of defect. Being able to quantify the bearing power consumption, as a function of the variables mentioned earlier, would make it possible to obtain optimal operating condition ranges that minimize energy consumption and maximize train energy efficiency.
Several theoretical studies were performed to estimate the power consumption within railroad bearings, but those studies lacked experimental validation. For almost a decade now, the University Transportation Center for Railway Safety (UTCRS) at the University of Texas Rio Grande Valley (UTRGV) has been collecting power consumption data for railroad bearings under various loads, speeds, ambient temperatures, and bearing condition. The objective of this ongoing study is to use the experimentally acquired power consumption to come up with a correlation that can be used to quantify the bearing power consumption as a function of load, speed, ambient temperature, and bearing condition. Once obtained, the model can then be used to determine optimal operating practices that maximize the railroad bearing energy efficiency. In addition, the developed model will provide insight into possible areas of improvement for the next generation of energy efficient railroad bearings. This paper will discuss ongoing work including experimental setup and findings of energy consumption of bearings as function of railcar load, train speed, condition of bearing whether it is healthy or defective, and type of defect. Findings of energy consumption are converted into approximations of diesel gallons to quantify the effect of nominal energy consumption of the bearings and show economic value and environmental impact
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