A theoretical model of wage discrimination with inspection fines

In neoclassical models, workers are classified a priori into discrimination groups. We develop a probabilistic model of wage discrimination in which workers need not be classified a priori. Our model is a generalization of the standard framework, whereas Becker's model is an extreme case. A second implication is that the traditional approach to measuring discrimination (the Oaxaca–Blinder approach) must be modified to take into account this probabilistic framework.

Introducing Fiji and ICY image processing techniques in ichnological research as a tool for sedimentary basin analysis

Some features of trace fossils are not easy to determine due to limited vissibility of trace fossils. Here, we applied two image processing techniques (Fiji and ICY) to ichnological studies and we compare them with the previously used high-resolution image treatment method. , discussing their usefulness for ichnological studies. Then, these are compared with a high resolution image treatment. These techniques are revealed as rapid alternatives for estimation of some ichnological features, being so useful for the first stages of research, when a detailed analysis is not needed

A multi-objective approach to the cash management problem

[EN] Cash management is concerned with optimizing costs of short-term cash policies of a company. Different optimization models have been proposed in the literature whose focus has been only placed on a single objective, namely, on minimizing costs. However, cash managers may also be interested in risk associated to cash policies. In this paper, we propose a multi-objective cash management model based on compromise programming that allows cash managers to select the best policies, in terms of cost and risk, according to their risk preferences. The model is illustrated through several examples using real data from an industrial company, alternative cost scenarios and two different measures of risk. As a result, we provide cash managers with a new tool to allow them deciding on the level of risk to take in daily decision-making.Work partially funded by projects Collectiveware TIN2015-66863-C2-1-R (MINECO/FEDER) and 2014 SGR 118.Salas-Molina, F.; Pla Santamaría, D.; Rodriguez Aguilar, JA. (2016). A multi-objective approach to the cash management problem. Annals of Operations Research. 1-15. https://doi.org/10.1007/s10479-016-2359-1S115Baccarin, S. (2009). Optimal impulse control for a multidimensional cash management system with generalized cost functions. European Journal of Operational Research, 196(1), 198–206.Ballestero, E. (1998). Approximating the optimum portfolio for an investor with particular preferences. Journal of the Operational Research Society, 49(9), 998–1000.Ballestero, E. (2005). Mean-semivariance efficient frontier: A downside risk model for portfolio selection. Applied Mathematical Finance, 12(1), 1–15.Ballestero, E., & Pla-Santamaria, D. (2004). Selecting portfolios for mutual funds. Omega, 32(5), 385–394.Ballestero, E., & Romero, C. (1998). Multiple criteria decision making and its applications to economic problems. Berlin: Springer.Bates, T. W., Kahle, K. M., & Stulz, R. M. (2009). Why do US firms hold so much more cash than they used to? The Journal of Finance, 64(5), 1985–2021.Baumol, W. J. (1952). The transactions demand for cash: An inventory theoretic approach. The Quarterly Journal of Economics, 66(4), 545–556.Chen, X., & Simchi-Levi, D. (2009). A new approach for the stochastic cash balance problem with fixed costs. Probability in the Engineering and Informational Sciences, 23(04), 545–562.Constantinides, G. M., & Richard, S. F. (1978). Existence of optimal simple policies for discounted-cost inventory and cash management in continuous time. Operations Research, 26(4), 620–636.da Costa Moraes, M. B., & Nagano, M. S. (2014). Evolutionary models in cash management policies with multiple assets. Economic Modelling, 39, 1–7.da Costa Moraes, M. B., Nagano, M.S., Sobreiro, V. A. (2015). Stochastic cash flow management models: A literature review since the 1980s. In P. Guarnieri (Ed.), Decision models in engineering and management. Decision engineering (pp. 11–28). Switzerland: Springer.Eppen, G. D., & Fama, E. F. (1969). Cash balance and simple dynamic portfolio problems with proportional costs. International Economic Review, 10(2), 119–133.Gao, H., Harford, J., & Li, K. (2013). Determinants of corporate cash policy: Insights from private firms. Journal of Financial Economics, 109(3), 623–639.Girgis, N. M. (1968). Optimal cash balance levels. Management Science, 15(3), 130–140.Gormley, F. M., & Meade, N. (2007). The utility of cash flow forecasts in the management of corporate cash balances. European Journal of Operational Research, 182(2), 923–935.Gregory, G. (1976). Cash flow models: A review. Omega, 4(6), 643–656.Markowitz, H. (1952). Portfolio Selection. The Journal of Finance, 7(1), 77–91.McNeil, A. J., Frey, R., & Embrechts, P. (2005). Quantitative risk management: Concepts, techniques and tools. Princeton: Princeton University Press.Melo, M. A., & Bilich, F. (2013). Expectancy balance model for cash flow. Journal of Economics and Finance, 37(2), 240–252.Miller, M. H., & Orr, D. (1966). A model of the demand for money by firms. The Quarterly Journal of Economics, 80(3), 413–435.Myers, S. C., & Brealey, R. A. (2003). Principles of corporate finance (7th ed.). NewYork: McGraw-Hill.Neave, E. H. (1970). The stochastic cash balance problem with fixed costs for increases and decreases. Management Science, 16(7), 472–490.Penttinen, M. J. (1991). Myopic and stationary solutions for stochastic cash balance problems. European Journal of Operational Research, 52(2), 155–166.Pinkowitz, L., Stulz, R. M., & Williamson, R. (2016). Do US firms hold more cash than foreign firms do? Review of Financial Studies, 29(2), 309–348.Pla-Santamaria, D., & Bravo, M. (2013). Portfolio optimization based on downside risk: A mean-semivariance efficient frontier from dow jones blue chips. Annals of Operations Research, 205(1), 189–201.Premachandra, I. (2004). A diffusion approximation model for managing cash in firms: An alternative approach to the Miller–Orr model. European Journal of Operational Research, 157(1), 218–226.Roijers, D. M., Vamplew, P., Whiteson, S., & Dazeley, R. (2013). A survey of multi-objective sequential decision-making. Journal of Artificial Intelligence Research, 48(1), 67–113.Ross, S. A., Westerfield, R., & Jordan, B. D. (2002). Fundamentals of corporate finance (6th ed.). NewYork: McGraw-Hill.Sharpe, W. F. (1966). Mutual fund performance. The Journal of Business, 39(1), 119–138.Sharpe, W. F. (1994). The sharpe ratio. The Journal of Portfolio Management, 21(1), 49–58.Srinivasan, V., & Kim, Y. H. (1986). Deterministic cash flow management: State of the art and research directions. Omega, 14(2), 145–166.Steuer, R. E., Qi, Y., & Hirschberger, M. (2007). Suitable-portfolio investors, nondominated frontier sensitivity, and the effect of multiple objectives on standard portfolio selection. Annals of Operations Research, 152(1), 297–317.Stone, B. K. (1972). The use of forecasts and smoothing in control-limit models for cash management. Financial Management, 1(1), 72–84.Whalen, E. L. (1966). A rationalization of the precautionary demand for cash. The Quarterly Journal of Economics, 80(2), 314–324.Yu, P. L. (2013). Multiple-criteria decision making: Concepts, techniques, and extensions. Berlin: Springer.Zeleny, M. (1982). Multiple criteria decision making. NewYork: McGraw-Hill.Zopounidis, C. (1999). Multicriteria decision aid in financial management. European Journal of Operational Research, 119(2), 404–415

On the use of multiple criteria distance indexes to find robust cash management policies

[EN] Cash management decision-making can be handled from a multiobjective perspective by optimizing not only cost but also risk. Nevertheless, choosing the best policies under a changing context is by no means straightforward. To this end, we rely on compromise programming to incorporate robustness as an additional goal to cost and risk within a multiobjective framework. As a result, we propose to calculate robustness as a multiple criteria distance index that is able to identify the best compromise policies in terms of cost and risk. Such policies are also robust to cash flow regime changes. We show its utility by transforming the Miller and Orr s cash management model into its robust counterpart using real data from an industrial company.Ministerio de Economia y Competitividad [grant number Collectiveware TIN2015-66863-C2-1-R], [grant number 2014 SGR 118]. Work partially funded by projects Collectiveware TIN2015-66863-C2-1-R (MINECO/FEDER) and 2014 SGR 118.Salas-Molina, F.; Rodriguez-Aguilar, JA.; Pla Santamaría, D. (2019). On the use of multiple criteria distance indexes to find robust cash management policies. INFOR Information Systems and Operational Research. 57(3):345-360. https://doi.org/10.1080/03155986.2017.1282291S34536057

Characterizing compromise solutions for investors with uncertain risk preferences

[EN] The optimum portfolio selection for an investor with particular preferences was proven to lie on the normalized efficient frontier between two bounds defined by the Ballestero (1998) bounding theorem. A deeper understanding is possible if the decision-maker is provided with visual and quantitative techniques. Here, we derive useful insights as a way to support investor's decision-making through: (i) a new theorem to assess balance of solutions; (ii) a procedure and a new plot to deal with discrete efficient frontiers and uncertain risk preferences; and (iii) two quality metrics useful to predict long-run performance of investors.Work partially funded by projects Collectiveware TIN2015-66863-C2-1-R (MINECO/FEDER) and 2014 SGR 118Salas-Molina, F.; Rodriguez-Aguilar, JA.; Pla Santamaría, D. (2019). Characterizing compromise solutions for investors with uncertain risk preferences. Operational Research. 19(3):661-677. https://doi.org/10.1007/s12351-017-0309-6S661677193Amiri M, Ekhtiari M, Yazdani M (2011) Nadir compromise programming: a model for optimization of multi-objective portfolio problem. Expert Syst Appl 38(6):7222–7226Ballestero E (1998) Approximating the optimum portfolio for an investor with particular preferences. J Oper Res Soc 49:998–1000Ballestero E (2007) Compromise programming: a utility-based linear-quadratic composite metric from the trade-off between achievement and balanced (non-corner) solutions. Eur J Oper Res 182(3):1369–1382Ballestero E, Pla-Santamaria D (2004) Selecting portfolios for mutual funds. Omega 32(5):385–394Ballestero E, Pla-Santamaria D, Garcia-Bernabeu A, Hilario A (2015) Portfolio selection by compromise programming. In: Ballestero E, Pérez-Gladish B, Garcia-Bernabeu A (eds) Socially responsible investment. A multi-criteria decision making approach, vol 219. Springer, Switzerland, pp 177–196Ballestero E, Romero C (1996) Portfolio selection: a compromise programming solution. J Oper Res Soc 47(11):1377–1386Ballestero E, Romero C (1998) Multiple criteria decision making and its applications to economic problems. Kluwer Academic Publishers, BerlinBilbao-Terol A, Pérez-Gladish B, Arenas-Parra M, Rodríguez-Uría MV (2006) Fuzzy compromise programming for portfolio selection. Appl Math Comput 173(1):251–264Bravo M, Ballestero E, Pla-Santamaria D (2012) Evaluating fund performance by compromise programming with linear-quadratic composite metric: an actual case on the caixabank in spain. J Multi-Criteria Decis Anal 19(5–6):247–255Ehrgott M, Klamroth K, Schwehm C (2004) An MCDM approach to portfolio optimization. Eur J Oper Res 155(3):752–770Fawcett T (2006) An introduction to ROC analysis. Pattern Recognit Lett 27(8):861–874Hernández-Orallo J, Flach P, Ferri C (2013) ROC curves in cost space. Mach Learn 93(1):71–91Markowitz H (1952) Portfolio selection. J Finance 7(1):77–91Pla-Santamaria D, Bravo M (2013) Portfolio optimization based on downside risk: a mean-semivariance efficient frontier from dow jones blue chips. Ann Oper Res 205(1):189–201Ringuest JL (1992) Multiobjective optimization: behavioral and computational considerations. Springer Science & Business Media, BerlinSteuer RE, Qi Y, Hirschberger M (2007) Suitable-portfolio investors, nondominated frontier sensitivity, and the effect of multiple objectives on standard portfolio selection. Ann Oper Res 152(1):297–317Xidonas P, Mavrotas G, Krintas T, Psarras J, Zopounidis C (2012) Multicriteria portfolio management. Springer, BerlinYu P-L (1973) A class of solutions for group decision problems. Manag Sci 19(8):936–946Yu P-L (1985) Multiple criteria decision making: concepts, techniques and extensions. Plenum Press, BerlinZeleny M (1982) Multiple criteria decision making. McGraw-Hill, New Yor

Rubrics and Academic Performance in English as a Foreign Language Teaching: Assessing Writing Tasks

Using rubrics in foreign language teaching has become a popular procedure among academics around the world. Rubrics are useful tools to improve educational in-class processes, as well as, to assess students’ learning outcomes. This study aims to determine whether the application of rubrics as an assessment tool influences eighth-grade foreign language students’ Academic Performance.A diagnostic survey was applied to the teachers of the foreign language department at the high school to determine which assessment tools were used to assess and grade students’ writing class work. Twenty-eight students of eighth grade, classroom “D” (octavo año de educación básica class "D") and foreign language teachers of Unidad Educativa Colegio Militar Nº6 “Combatientes de Tapi (UECMCT), Riobamba, Ecuador, participated in the study. The Academic Performance data of the students was collected during the second term of the second five-month school period (quimester) and analyzed through figures and tables, where a written activity was assessed without the application of a rubric. The results of this first students’ performance assessment showed that many students were not proficient in learning. Subsequently, an assessment rubric was elaborated and applied as an evaluation instrument of a written activity during the third term of the second quimester. In this opportunity, as a result, a large number of students improved their performance and achieved the expected learning outcomes. The application of this assessment tool not only enhanced the Academic Performance of the students but also allowed the teacher to facilitate the assessment process

La actividad turística y el avance de las herramientas tecnológicas en los últimos años

En el siguiente trabajo de investigación se analizó la relación que tiene la actividad turística y el avance de las herramientas tecnológicas en los últimos años, además se realizó un análisis de las mejores prácticas sobre el uso de la tecnología como la ciudad de Málaga, que logró obtener la distinción de ciudad inteligente en todo el territorio español y como ha sido enfocado en el sector turístico para lograr obtener una mayor demanda y mejorar sus niveles de competitividad. Asimismo, se analizaron las experiencias del uso de la tecnología en Perú. La tecnología es una herramienta que ha influenciado mucho en la actividad turística, destacando su mayor uso en los últimos años, para ello se ha considerado realizar toda una revisión bibliográfica, partiendo de las ideas de turismo inteligente, sostenibilidad, la nueva tecnología usada a raíz de los efectos negativos ocasionados por la pandemia y la actividad turística como generador de empleo.In the following research work, the relationship between tourist activity and the advancement of technological tools in recent years was analyzed, as well as an analysis of the best practices on the use of technology such as the city of Malaga, which achieved obtain the distinction of smart city throughout the Spanish territory and how it has been focused on the tourism sector to achieve greater demand and improve its levels of competitiveness. Likewise, the experiences of the use of technology in Peru were analyzed. Technology is a tool that has greatly influenced tourism activity, highlighting its greater use in recent years, for which it has been considered to carry out a complete bibliographic review, starting from the ideas of intelligent tourism, sustainability, the new technology used as a result of the negative effects caused by the pandemic and tourism activity as a generator of employment

Insoluble γ-Tubulin–Containing Structures Are Anchored to the Apical Network of Intermediate Filaments in Polarized Caco-2 Epithelial Cells

We have previously shown that a thin (∼1 μm) layer of intermediate filaments located beneath the apical membrane of a variety of simple epithelial cells participates in the organization of apical microfilaments and microtubules. Here, I confirmed the apical distribution of γ-tubulin–containing structures (potential microtubule-organizing centers) in CACO-2 cells and demonstrated perfect colocalization of centrosomes and nearly 50% of noncentrosomal γ-tubulin with apical intermediate filaments, but not with apical F-actin. Furthermore, the antisense-oligonucleotide–mediated downregulation of cytokeratin 19, using two different antisense sequences, was more efficient than anticytoskeletal agents to delocalize centrosomes. Electron microscopy colocalization suggests that binding occurs at the outer boundary of the pericentriolar material. Type I cytokeratins 18 and 19 present in these cells specifically coimmunoprecipitated in multi-protein fragments of the cytoskeleton with γ-tubulin. The size and shape of the fragments, visualized at the EM level, indicate that physical trapping is an unlikely explanation for this result. Drastic changes in the extraction protocol did not affect coimmunoprecipitation. These results from three independent techniques, indicate that insoluble γ-tubulin–containing structures are attached to apical intermediate filaments

Colaboración eficaz y su implicancia en los procesos por delitos de corrupción de funcionarios en el Perú – 2023

La presente investigación tuvo como objetivo analizar las implicancias de la aplicación de la colaboración eficaz en los procesos de corrupción de funcionarios en el Perú; fue estudio teórico dogmático-normativo, con diseño no experimental cuya técnica fue el análisis de contenido, cuyo escenario de estudios fueron los procesos de corrupción de funcionarios y la aplicación de la colaboración eficaz, se utilizaron fichas bibliográficas y de resumen, y su procesamiento con el método hermenéutico; obteniendo como conclusiones: la experiencia en la investigación y combate de delitos complejos nacionales e internacionales, como los delitos de corrupción de funcionarios, se considera la intervención de la colaboración eficaz, por lo que, al aplicar esta técnica procesal, la investigación de estos delitos puede ser facilitada por la participación efectiva del imputado que decide participar en el proceso penal investigación. Asimismo, para lograr una colaboración eficaz, es necesario presentar pruebas significativas, proporcionar datos para las investigaciones penales y bajo la dirección del fiscal como titular de la investigación para evitar que determinados delitos por corrupción de funcionarios queden impunes, llegando a estar fuera del alcance de los fiscales, que de otro modo serían prácticamente imposibles de obtener para el esclarecimiento de estos delitos