5,190 research outputs found
Debt Financing and Efficiency in Agricultural Firms
In this work the effects of large- and short-term debts on efficiency are tested on a set of agricultural firms. Accounting data of crop, livestock, mixed and service firms are used. First, the efficiencies of the farms are obtained by using nonparametric methods (input-oriented DEA). Then, in a second stage, censored regressions are run with different kinds of explicative variables, including financial ratios. The results show a significative and positive relationship between short-term indebtedness and efficiency, which would be agree with some theories positing that firms with higher short-run obligations make additional efforts to satisfy their payments, and this leads to an improvement of efficiency.Debt financing, Efficiency, Agricultural sector, Nonparametric methods, Agricultural Finance,
Input Substitution in the Spanish Food Industry
Firm panel data sets over the period 1993 to 2002 are used to estimate translog production functions with labour, capital and material inputs for 9 Spanish food industries. To tackle the endogeneity of the regressors, the generalized method of moments estimations is employed. The specification tests reject the instrument variables only for 1 out of 9 estimates. The remaining 8 industries show evidence of homogeneity and constant returns to scale. Only one industry exhibits complete separability of all pairs of factors and thus translog is preferred to Cobb-Douglas specification for 7 industries. Substitutability and complementarity between production factors in response to price changes are studied through Morishima and Shadow elasticities. Substitutability between labor and capital and complementarity between labor and materials are the most common relationships.translog, elasticity of substitution, generalized method of moments, returns to scale, Agribusiness, C23, D24, L66,
CURRENT TECHNOLOGIES APPLIED TO URBAN SUSTAINABLE DEVELOPMENT
The present work organizes information in a systematized way, on environmental technologies applied to each of the tasks and activities that are performed in the cities, urban planning and development. These technologies are an updated part of all the technologies that can be applied, therefore, it is the state-of-the-art of new technologies applied to urban sustainable development which mostly are processes, instruments of measurement, simulators, equipment, materials, Software and Hardware that are of great help for urbanism designers and promoters of urbanism in the cities development. These technologies, which are described in the present article, have been selected on the basis of their up-to-dateness and application in the main sectors or fields of development and it is important to mention that only the most recent and influential on urban development and environmental technology have been chosen. The main objective is to provide an overview of the state-of-the art of these environmental technologies, and how we, designers, architects and promoters of urban development, can apply and use a number of technologies in urban planning with an environmental approach.sustainable urbanism, new technologies, development, tools.
INTEGRATION OF SERVICE LIFE IN THE PROCESS OF MANAGEMENT AND DESIGN OF BUILDINGS
This article approaches the regulatory framework on the service life of constructed assets and its integration into the management and design process of sustainable buildings. The importance of this study is to be found on the fact that currently, most of the building designers do not apply the integration and planning of service life into the process of management and design of constructions. Because of this, ISO (International Standard Organization) regulations are approached; said regulations are referred to the planning of service life of buildings, explaining and describing their relevance in the process of design. Basic principles of the sustainable planning, derived from Leadership in Energy and Environmental Design® method in the United States and Canada, are presented as well as the relation with the aforementioned International Standard Organization regulations on the service life of buildings, specifically that of ISO 15686.Design process, Regulations, Service life, Sustainable building, Sustainable management.
Optimal Control and Sensitivity Analysis of a Fractional Order TB Model
A Caputo fractional-order mathematical model for the transmission dynamics of
tuberculosis (TB) was recently proposed in [Math. Model. Nat. Phenom. 13
(2018), no. 1, Art. 9]. Here, a sensitivity analysis of that model is done,
showing the importance of accuracy of parameter values. A fractional optimal
control (FOC) problem is then formulated and solved, with the rate of treatment
as the control variable. Finally, a cost-effectiveness analysis is performed to
assess the cost and the effectiveness of the control measures during the
intervention, showing in which conditions FOC is useful with respect to
classical (integer-order) optimal control.Comment: This is a preprint of a paper whose final and definite form is with
'Statistics Opt. Inform. Comput.', Vol. 7, No 2 (2019). See
[http://www.IAPress.org]. Submitted 09/Sept/2018; Revised 10/Dec/2018;
Accepted 11/Dec/2018. arXiv admin note: text overlap with arXiv:1801.09634,
arXiv:1810.0690
Optimal control of a fractional order epidemic model with application to human respiratory syncytial virus infection
A human respiratory syncytial virus surveillance system was implemented in
Florida in 1999, to support clinical decision-making for prophylaxis of
premature newborns. Recently, a local periodic SEIRS mathematical model was
proposed in [Stat. Optim. Inf. Comput. 6 (2018), no.1, 139--149] to describe
real data collected by Florida's system. In contrast, here we propose a
non-local fractional (non-integer) order model. A fractional optimal control
problem is then formulated and solved, having treatment as the control.
Finally, a cost-effectiveness analysis is carried out to evaluate the cost and
the effectiveness of proposed control measures during the intervention period,
showing the superiority of obtained results with respect to previous ones.Comment: This is a preprint of a paper whose final and definite form is with
'Chaos, Solitons & Fractals', available from
[http://www.elsevier.com/locate/issn/09600779]. Submitted 23-July-2018;
Revised 14-Oct-2018; Accepted 15-Oct-2018. arXiv admin note: substantial text
overlap with arXiv:1801.0963
Breast Cancer Risk After Ovarian Stimulation for In Vitro Fertilization
The study by Dr van den Belt-Dusebout and colleagues1 investigated a debated aspect of reproductive medicine: breast cancer risk following ovarian stimulation for in vitro fertilization (IVF).2-5 The authors concluded that “these findings are consistent with absence of a significant increase in long-term risk of breast cancer among IVF-treated women”.1 However, some important points should be discussed.
For about 23 % of women, sub-fertility diagnosis and number of IVF cycles were collected using a questionnaire since medical records were not available. This high rate threatens the reliability of results. It is not possible to compare a detailed report of official medical records with data deriving from subjective memory of treatments received many years before. This may be a strong bias, because reproductive medicine, IVF strategies and the pharmacological protocols have changed rapidly in the last decades.
Dates of diagnosis and histology were reported but unfortunately not disease staging. It would be interesting to investigate if ovarian stimulation with the use of IVF techniques can promote the occurrence of biologically different types of breast cancer, as in the case of tamoxifen-related endometrial cancer, a neoplasia with better prognostic profile and outcome.
Also, the authors reported that breast cancer risk decreased with more IVF cycles (7 or more compared with 1-2). They suggested as potential explanations that women treated with more IVF cycles received more hCG or had longer periods of down-regulation with low estradiol and progesterone levels, or the women requiring more IVF cycles were inherently different. It is difficult to provide a definitive conclusion since the clinical outcomes of IVF cycles were not reported. The decreased risk in women treated with many IVF cycles also could be related to the improvement of ovarian function after repeated endocrine stimulations. Infertility and infertility-related nulliparity must be considered as risk factors for breast cancer, and prolonged treatment of anovulatory or poor ovulatory cycles could be one approach for restoring normal ovarian activity and reducing breast cancer risk
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L&D in the ED: A Game-Based Approach to Learning High-Risk Obstetric Emergencies.
IntroductionTeaching emergency medicine residents the principles of obstetric emergencies is a challenging task, as these emergencies are uncommon in general practice and include specific maneuvers for difficult and precipitous deliveries. These requirements are not easy to satisfy in a standard lecture and are labor intensive for small groups. This resource is a board game that leverages near-peer teaching, engages student collaboration, and supports friendly competition.MethodsThe game was designed to be used by emergency medicine residents and emphasized the evaluation and management of acute issues related to labor and delivery (L&D). To play the game, three to four learners took turns answering questions. Each correct answer was awarded points for forward movement on the game board. The first person to reach the end of the game won. A faculty moderator circulated among the players to clarify questions or answers as needed.ResultsOur residents loved this resource. They were able to teach each other throughout the game while using reference materials. Participants rated the educational value of the L&D board game as 4.81 (out of 5), as compared to 4.37 for prior lectures covering the same topics. The game was rated similarly to delivery procedural skills workshops implemented in prior years (4.62-4.82).DiscussionGame-based exercises are low-tech, highly interactive teaching tools enabling students to learn from each other in a fun and engaging way. Although we did not assess knowledge retention, this activity's educational value was rated similarly to delivery procedural skills sessions
SUSTAINABLE MANAGEMENT OF DOMESTIC WATER RESIDUES AND DIMINUTION OF DISCHARGES INTO MUNICIPAL COLLECTORS IN MEXICO
This work is a study on the sustainable management of water according to the regulation and recommendations of sustainable architectural design of the environmental model by LEED® (Leadership in Energy and Environmental Design), particularly in respect to the adequate management of household residual water discharge into the municipal collectors. The study lays the bases to decrease the volume of residual water discharge into municipal collectors, which brings along many benefits of the environmental, social and economic kinds in the place where it is applied. A case study for the municipality of Metepec, State of Mexico, Mexico, will be approached; firstly, carrying out a diagnosis of wastewater discharge from buildings in the municipality to learn the volumes that are generated in order to run a study on the diminution of said residues into the collectors, hence decreasing the discharges allowed for at Federal level. This work might be used as an instrument by the different sectors of public administration in Mexico, mainly the municipal governments, in charge of water management, as well as designers, urbanists, architects and those in charge of designing human settlements of any kind.water discharge, municipal waste, pollution, sustainable urbanism.
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