Gestión de la cadena de suministros desde la dinámica de sistemas. Aproximación al mejoramiento de la toma de decisiones

El objetivo de este trabajo es hacer un estudio sobre la cadena de suministros en organizaciones empresariales desde la Dinámica de Sistemas y como esta puede aportar al desempeño y el control de las cadenas de suministros. Se buscará Abordar el cocimiento sobre tres perspectivas de Supply Chain y su relación con la dinámica de sistemas. También se buscará identificar los tipos de integración en las actividades de la gestión en la cadena de suministros y sus horizontes de planeación. Por último, se pretende analizar las aplicaciones de Supply Chain Management que se han basado en el uso de la metodología de dinámica de sistemas. Para esto, la investigación empezará por definir la problemática alrededor de unir estas dos áreas y definirá el marco teórico que fundan estas dos disciplinas. Luego se abordará la metodología usada por la Dinámica de Sistemas y los diferentes aspectos de la cadena de suministros. Se Ahondará en el acercamiento de las dos disciplinas y como convergen ayudando la SD a la SCM (Supply Chain Management). En este punto también se describirán los trabajos en los diferentes enfoques que se han hecho a partir de uso de la dinámica de sistemas. Por último, presentaremos las correspondientes conclusiones y comentarios acerca de este campo de investigación y su pertinencia en el campo de la Supply Chain. Esta investigación abarca dos grandes corrientes de pensamiento, una sistémica, a través de la metodología de dinámica de sistemas y la otra, lógico analítica la cual es usada en Supply Chain. Se realizó una revisión de la literatura sobre las aplicaciones de dinámica de sistemas (SD) en el área de Supply Chain, sus puntos en común y se documentaron importantes empleos de esta metodología que se han hecho en la gestión de la cadena de suministros.

Development and application of model of resource utilization, costs, and outcomes for stroke (MORUCOS): an Australian economic model for stroke.

Objectives: To outline the development, structure, data assumptions, and application of an Australian economic model for stroke (Model of Resource Utilization, Costs, and Outcomes for Stroke [MORUCOS]). Methods: The model has a linked spreadsheet format with four modules to describe the disease burden and treatment pathways, estimate prevalence-based and incidence-based costs, and derive life expectancy and quality of life consequences. The model uses patient-level, community-based, stroke cohort data and macro-level simulations. An interventions module allows options for change to be consistently evaluated by modifying aspects of the other modules. To date, model validation has included sensitivity testing, face validity, and peer review. Further validation of technical and predictive accuracy is needed. The generic pathway model was assessed by comparison with a stroke subtypes (ischemic, hemorrhagic, or undetermined) approach and used to determine the relative cost-effectiveness of four interventions. Results: The generic pathway model produced lower costs compared with a subtypes version (total average first-year costs/case AUD$15,117 versus AUD$17,786, respectively). Optimal evidence-based uptake of anticoagulation therapy for primary and secondary stroke prevention and intravenous thrombolytic therapy within 3 hours of stroke were more cost-effective than current practice (base year, 1997). Conclusions: MORUCOS is transparent and flexible in describing Australian stroke care and can effectively be used to systematically evaluate a range of different interventions. Adjusting results to account for stroke subtypes, as they influence cost estimates, could enhance the generic model.

Reliability and validity of self-reported burnout in college students: A cross randomized comparison of paper-and-pencil vs. online administration

Internet data collection is becoming increasingly popular in all research fields dealing with human perceptions, behaviors and opinions. Advantages of internet data collection, when compared to the traditional paper-and-pencil format, include reduced costs, automatic database creation, and the absence of researcher-related bias effects, such as availability and complete anonymity. However, the validity and reliability of internet gathered data must be established, in comparison to the usual paper-and-pencil accepted formats, before an inferential analysis can be done. In this study, we compared questionnaire data gathered from the internet with that from the traditional paper-and-pencil in a sample of college students. The questionnaires used were the Maslach Burnout Inventory - Student Survey (MBI-SS), the Oldenburg Burnout Inventory (OBI-SS) and the Copenhagen Burnout Inventory (CBI-SS). Data was gathered through a within-subject cross randomized and counterbalanced design, on both internet and paper-and-pencil formats. The results showed no interference in the application order, and a good reliability for both formats. However, concordance between answers was generally higher in the paper-and-pencil format than on the internet. The factorial structure was invariant in the three burnout inventories. Data gathered in this study supports the Internet as a convenient, user-friendly, comfortable and secure data gathering method which does not affect the accepted factorial structures existent in the paper format of the three burnout inventories used. (C) 2011 Elsevier Ltd. All rights reserved.

Bioremediation of PAHs - Limitations and soultions

Introduction 1.1 Occurrence of polycyclic aromatic hydrocarbons (PAH) in the environment Worldwide industrial and agricultural developments have released a large number of natural and synthetic hazardous compounds into the environment due to careless waste disposal, illegal waste dumping and accidental spills. As a result, there are numerous sites in the world that require cleanup of soils and groundwater. Polycyclic aromatic hydrocarbons (PAHs) are one of the major groups of these contaminants (Da Silva et al., 2003). PAHs constitute a diverse class of organic compounds consisting of two or more aromatic rings with various structural configurations (Prabhu and Phale, 2003). Being a derivative of benzene, PAHs are thermodynamically stable. In addition, these chemicals tend to adhere to particle surfaces, such as soils, because of their low water solubility and strong hydrophobicity, and this results in greater persistence under natural conditions. This persistence coupled with their potential carcinogenicity makes PAHs problematic environmental contaminants (Cerniglia, 1992; Sutherland, 1992). PAHs are widely found in high concentrations at many industrial sites, particularly those associated with petroleum, gas production and wood preserving industries (Wilson and Jones, 1993). 1.2 Remediation technologies Conventional techniques used for the remediation of soil polluted with organic contaminants include excavation of the contaminated soil and disposal to a landfill or capping - containment - of the contaminated areas of a site. These methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and containment method is only an interim solution since the contamination remains on site, requiring monitoring and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants, if possible, or transform them into harmless substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (for example, base-catalyzed dechlorination, UV oxidation). However, these methods have significant disadvantages, principally their technological complexity, high cost , and the lack of public acceptance. Bioremediation, on the contrast, is a promising option for the complete removal and destruction of contaminants. 1.3 Bioremediation of PAH contaminated soil & groundwater Bioremediation is the use of living organisms, primarily microorganisms, to degrade or detoxify hazardous wastes into harmless substances such as carbon dioxide, water and cell biomass Most PAHs are biodegradable unter natural conditions (Da Silva et al., 2003; Meysami and Baheri, 2003) and bioremediation for cleanup of PAH wastes has been extensively studied at both laboratory and commercial levels- It has been implemented at a number of contaminated sites, including the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989, the Mega Borg spill off the Texas coast in 1990 and the Burgan Oil Field, Kuwait in 1994 (Purwaningsih, 2002). Different strategies for PAH bioremediation, such as in situ , ex situ or on site bioremediation were developed in recent years. In situ bioremediation is a technique that is applied to soil and groundwater at the site without removing the contaminated soil or groundwater, based on the provision of optimum conditions for microbiological contaminant breakdown.. Ex situ bioremediation of PAHs, on the other hand, is a technique applied to soil and groundwater which has been removed from the site via excavation (soil) or pumping (water). Hazardous contaminants are converted in controlled bioreactors into harmless compounds in an efficient manner. 1.4 Bioavailability of PAH in the subsurface Frequently, PAH contamination in the environment is occurs as contaminants that are sorbed onto soilparticles rather than in phase (NAPL, non aqueous phase liquids). It is known that the biodegradation rate of most PAHs sorbed onto soil is far lower than rates measured in solution cultures of microorganisms with pure solid pollutants (Alexander and Scow, 1989; Hamaker, 1972). It is generally believed that only that fraction of PAHs dissolved in the solution can be metabolized by microorganisms in soil. The amount of contaminant that can be readily taken up and degraded by microorganisms is defined as bioavailability (Bosma et al., 1997; Maier, 2000). Two phenomena have been suggested to cause the low bioavailability of PAHs in soil (Danielsson, 2000). The first one is strong adsorption of the contaminants to the soil constituents which then leads to very slow release rates of contaminants to the aqueous phase. Sorption is often well correlated with soil organic matter content (Means, 1980) and significantly reduces biodegradation (Manilal and Alexander, 1991). The second phenomenon is slow mass transfer of pollutants, such as pore diffusion in the soil aggregates or diffusion in the organic matter in the soil. The complex set of these physical, chemical and biological processes is schematically illustrated in Figure 1. As shown in Figure 1, biodegradation processes are taking place in the soil solution while diffusion processes occur in the narrow pores in and between soil aggregates (Danielsson, 2000). Seemingly contradictory studies can be found in the literature that indicate the rate and final extent of metabolism may be either lower or higher for sorbed PAHs by soil than those for pure PAHs (Van Loosdrecht et al., 1990). These contrasting results demonstrate that the bioavailability of organic contaminants sorbed onto soil is far from being well understood. Besides bioavailability, there are several other factors influencing the rate and extent of biodegradation of PAHs in soil including microbial population characteristics, physical and chemical properties of PAHs and environmental factors (temperature, moisture, pH, degree of contamination). Figure 1: Schematic diagram showing possible rate-limiting processes during bioremediation of hydrophobic organic contaminants in a contaminated soil-water system (not to scale) (Danielsson, 2000). 1.5 Increasing the bioavailability of PAH in soil Attempts to improve the biodegradation of PAHs in soil by increasing their bioavailability include the use of surfactants , solvents or solubility enhancers.. However, introduction of synthetic surfactant may result in the addition of one more pollutant. (Wang and Brusseau, 1993).A study conducted by Mulder et al. showed that the introduction of hydropropyl-ß-cyclodextrin (HPCD), a well-known PAH solubility enhancer, significantly increased the solubilization of PAHs although it did not improve the biodegradation rate of PAHs (Mulder et al., 1998), indicating that further research is required in order to develop a feasible and efficient remediation method. Enhancing the extent of PAHs mass transfer from the soil phase to the liquid might prove an efficient and environmentally low-risk alternative way of addressing the problem of slow PAH biodegradation in soil.

Individual Differences in First and Fourth Year College Women’s Short Term Mating Strategy Preferences and Perceptions

Using survey methodology, a cross sectional study was undertaken to ascertain whether first and fourth year college women have different perceptions and behavior associated with short term mating preferences. It was hypothesized that after incurring significant negative or costly experiences associated with hooking up, fourth year women would prefer men who had qualities associated with a desired long term partner as opposed to characteristics associated with short term mating partners. The results were partially consistent with the hypothesis. Reported preferences in a desired partner and perspective on hooking up differ between first and fourth year groups. No difference was found between frequency and willingness to hookup between the two groups. The findings are explained in terms of evolutionary theory, social exchange theory, and sexual script concepts.

Erfahrungen aus England: Das Beispiel Cambridge

Anhand des Beispiels Cambridge werden die Erfahrungen mit dem BA-Studiengang in England vorgestellt. Hohe Leistungsanforderungen sowohl für die Studierenden als auch die Lehrenden sind kennzeichnend – um so wichtiger erscheinen entsprechende Studienbetreuung/-begleitung sowie eine gründliche Vorbereitung der Lehre. Das College hat an diesem Punkt Züge eines Dienstleistungsbetriebs für die Studierenden, auch wenn der Forschung nach wie vor eine große Bedeutung zukommt. Das MA-Studium hebt sich durch seine stärkere wissenschaftliche Ausrichtung deutlich vom BA-Studiengang ab. Zwar ist im Studium die global angelegte Wissensordnung erkennbar, doch kann es gerade durch den Zeitdruck durchaus zu einer thematischen Engführung kommen. Mit Blick auf die deutsche Situation erscheinen folgende Aspekte als besonders wichtig: verbesserte Betreuung der Studenten sowohl durch eine vergrößerte Anzahl der Lehrenden als auch durch ein neues Ethos der Lehre; materielle Verbesserung der Studienbedingungen; thematische Ausweitung des Studienangebots auf europäische und außereuropäische Bereiche.

Na 1 Nachlass Max Horkheimer, 19 - Korrespondenzen u.a. mit Alfred Haas (p. I 10, 1-250)

20 Briefe zwischen Alfred Haas und Max Horkheimer, 1935-1941; 2 Briefe von Willy Haas an Max Horkheimer, 1938; 3 Briefe zwischen Virginia Haber und Max Horkheimer, 12.09.1945, August 1945; 7 Briefe zwischen Hugo Hahn und Max Horkheimer, 1942-1946; 1 Brief von Max Horkheimer an Charles G. Haines, 23.10.1940; 1 Brief von Max Horkheimer an Hall, 02.07.1939; 2 Briefe zwischen H. Duncan Hall und Max Horkheimer, 04.08.1939, 24.07.1939; 2 Briefe zwsichen Herbert Berkerath und Max Horkheimer, 10.10.1939, 09.10.1939; 23 Briefe zwischen Wolfgang Hallgarten und Max Horkheimer, 1937-1941; 1 Brief von Max Horkheimer an die American Philosophic Society Philadelphia, 15.04.1940; 2 Briefe zwischen Betty Drury und Max Horkheimer, 29.02.1940, 20.02.1940; 6 Briefe zwischen Nina Almond und Max Horkheimer, 1939; 1 Brief von Ruth E. Hollander an Max Horkheimer, 08.09.1938; 1 Brief von dem Brooklyn College an Wolfgang Hallgarten, 29.04.1938; 4 briefe zwischen dem Brooklyn College und Max Horkheimer, 18.05.1938, 17.05.1938; 2 Briefe zwischen Robert Maynard Hutchins und Max Horkheimer, 02.11.1937, 28.10.1937; 2 Briefe zwsichen Hardt und Max Horkheimer, 01.10.1943; 4 Briefe zwischen Gertrude Hardt und Max Horkheimer, 1947-1948; 4 Briefe zwischen den Harper & Brothers New York und Max Horkheimer, 24.10.1950, 1950; 1 Brief von Friedrich Pollock an Margot von Mendelssohn, 13.09.1950; 1 Brief von Hartoch an Max Horkheimer, 09.06.1937; 4 Briefe zwischen dem Harvard College Cambridge Massachusetts und Max Horkheimer, 1939-1940; 3 Briefe zwischen Felix Hase und Max Horkheimer, 1936, 13.03.1936; 1 Brief von Freda E. Hecht an Max Horkheimer, 01.03.1947; 1 Brief von Ernest S. Hediger an Max Horkheimer, 02.09.1940; 2 Briefe zwischen Agnes Heilbut und Max Horkheimer, 18.07.1938,; 7 Briefe zwischen Eduard Heimann und Max Horkheimer, 1936-1939; 1 Brief von Fritz Hein an Max Horkheimer, 14.06.1949; 2 Briefe zwischen Walter Heinemann und Max Horkheimer, 15.02.1945, 12.03.1945; 2 Briefe zwischen Philipp Heller und Max Horkheimer, 16.09.1944, 09.10.1944; 1 Brief von Max Horkheimer an Hellmann, 23.03.1939; 4 Briefe zwischen L. E. Hellmann und Max Horkheimer, 1939; 4 Briefe zwischen P. A. Hemerijk und Max Horkheimer, 1936-1937, 03.02.1936; 5 Briefe zwischen Carl G. Hempel und Max Horkheimer, 1939-1941; 1 Lebenslauf von Hans Henning; 1 Brief von Else Henschke an Max Horkheimer, 24.07.1940; 1 Briefe von Isi Hepner an Max Horkheimer, 23.01.1941; 1 Brief von Leo Löwenthal an Isi Hepner, 03.02.1941; 1 Brief von Gertrude E. Herman anMax Horkheimer, 10.12.1949; 1 Brief von Wilhelm G. Hertz an Max Horkheimer, 29.09.1938; 2 Briefe zwischen Wieland Herzfelde und der National City Bank of New York, 28.11.1939, 30.11.1939; 2 Briefe zwischen Karl Hess und Max Horkheimer, 14.08.1935, 25.10.1934; 4 Briefe zwischen Karl Heymann und Max Horkheimer, 1947, 1949; 19 Briefe zwischen Robert Hilb und Max Horkheimer, 1937-1941; 2 Briefe zwischen Joseph Rosenthal und Max Horkheimer, 12.11.1940, 25.10.1940; 2 Briefe zwischen Henry Church und Max Horkheimer, 14.12.1940, 18.12.1940; 1 Brief von Ellen Hilb an Max Horkheimer, 11.03.1938; 1 Brief von Emil Hilb an Max Horkheimer, 15.04.1939; 2 Briefe zwischen Yoshitaro Hirano und Max Horkheimer, 1936, 23.01.1936; 2 Briefe von Max Horkheimer an Hirsch, 1938; 1 Brief von Arnold Hirsch an Max Horkheimer, 14.07.1949; 4 Briefe zwischen Charles Hirsch und Max Horkheimer, 1937, 1938; 2 Briefe von Max Horkheimer an Ernst Hirsch, Oktober 1938; 1 Brief von Max Horkheimer an Julius Hirsch, 24.02.1942;

Predictive validity of the personal background and preparation survey and effectiveness of targeted interventions among health science community college students

Existing data, collected from 1st-year students enrolled in a major Health Science Community College in the south central United States, for Fall 2010, Spring 2011, Fall 2011 and Spring 2012 semesters as part of the "Online Navigational Assessment Vehicle, Intervention Guidance, and Targeting of Risks (NAVIGATOR) for Undergraduate Minority Student Success" with CPHS approval number HSC-GEN-07-0158, was used for this thesis. The Personal Background and Preparation Survey (PBPS) and a two-question risk self-assessment subscale were administered to students during their 1st-year orientation. The PBPS total risk score, risk self-assessment total and overall scores, and Under Representative Minority Student (URMS) status were recorded. The purpose of this study is to evaluate and report the predictive validity of the indicators identified above for Adverse Academic Status Events (AASE) and Nonadvancement Adverse Academic Status Events (NAASE) as well as the effectiveness of interventions targeted using the PBPS among a diverse population of health science community college students. The predictive validity of the PBPS for AASE has previously been demonstrated among health science professions and graduate students (Johnson, Johnson, Kim, & McKee, 2009a; Johnson, Johnson, McKee, & Kim, 2009b). Data will be analyzed using binary logistic regression and correlation using SPSS 19 statistical package. Independent variables will include baseline- versus intervention-year treatments, PBPS, risk self-assessment, and URMS status. The dependent variables will be binary AASE and NAASE status. ^ The PBPS was the first reliable diagnostic and prescriptive instrument to establish documented predictive validity for student Adverse Academic Status Events (AASE) among students attending health science professional schools. These results extend the documented validity for the PBPS in predicting AASE to a health science community college student population. Results further demonstrated that interventions introduced using the PBPS were followed by approximately one-third reduction in the odds of Nonadvancement Adverse Academic Status Events (NAASE), controlling for URMS status and risk self-assessment scores. These results indicate interventions introduced using the PBPS may have potential to reduce AASE or attrition among URMS and nonURMS attending health science community colleges on a broader scale; positively impacting costs, shortages, and diversity of health science professionals.^

Consolidation properties and strength characteristics of ODP Site 204-1244 sediments

Eight whole-core samples from Ocean Drilling Program Site 1244, Hydrate Ridge, Cascadia continental margin, were provided to Massachusetts Institute of Technology (Cambridge, Massachusetts, USA) for geotechnical characterization. The samples were collected from depths ranging from 5 to 136 meters below seafloor (mbsf). Seven of the eight whole-core samples were located within the gas hydrate stability zone, whereas the eighth sample was located in the free gas zone. Atterberg limits testing showed that the average liquid limit of the soil is 81% and the average plastic limit is 38%, giving an average plasticity index of 43%. The liquid limit is sensitive to oven drying, shown by a drop in liquid limit to 64% when tests were performed on an oven-dried sample. Loss on ignition averages 5.45 wt%. Constant rate of strain consolidation (CRSC) tests were performed to obtain the compression characteristics of the soil, as well as to determine the stress history of the site. CRSC tests also provided hydraulic conductivity and coefficient of consolidation characteristics for these sediments. The compression ratio (Cc) ranges from 0.340 to 0.704 (average = 0.568). Cc is fairly constant to a depth of 79 mbsf, after which Cc decreases downhole. The recompression ratio (Cr) ranges from 0.035 to 0.064 (average = 0.052). Cr is constant throughout the depth range. In situ hydraulic conductivity varies between 1.5 x 10**-7 and 3 x 10**-8 cm/s and shows no trend with depth. Ko-consolidated undrained compression/extension (CKoUC/E) tests were also performed to determine the peak undrained shear strength, stress-strain curve, and friction angle. The normalized undrained strength ranges from 0.29 to 0.35. The friction angle ranges from 27 to 37. Because of the limited amount of soil, CRSC and CKoUC/E tests were also conducted on resedimented specimens.

Reseña de Toner, J. (2012) Sesenta Millones de Romanos. La cultura del pueblo en la Antigua Roma. Barcelona: Crítica. Traducción de Luis Noriega, Título original, Popular Culture in Ancient Rome. Cambridge: Polity Press, 2009, pp. 363

En este trabajo comento el contenido y el enfoque del libro de Jerry Toner, director de estudios clásicos en el Hughes Hall College de la Universidad de Cambridge, quien en "Sesenta millones de romanos..." estudia y caracteriza la cultura popular como un conjunto de estrategias empleadas por el pueblo romano para enfrentar los desafíos de la vida cotidiana

Reseña de Toner, J. (2012) Sesenta Millones de Romanos. La cultura del pueblo en la Antigua Roma. Barcelona: Crítica. Traducción de Luis Noriega, Título original, Popular Culture in Ancient Rome. Cambridge: Polity Press, 2009, pp. 363

En este trabajo comento el contenido y el enfoque del libro de Jerry Toner, director de estudios clásicos en el Hughes Hall College de la Universidad de Cambridge, quien en "Sesenta millones de romanos..." estudia y caracteriza la cultura popular como un conjunto de estrategias empleadas por el pueblo romano para enfrentar los desafíos de la vida cotidiana

Reseña de Toner, J. (2012) Sesenta Millones de Romanos. La cultura del pueblo en la Antigua Roma. Barcelona: Crítica. Traducción de Luis Noriega, Título original, Popular Culture in Ancient Rome. Cambridge: Polity Press, 2009, pp. 363

En este trabajo comento el contenido y el enfoque del libro de Jerry Toner, director de estudios clásicos en el Hughes Hall College de la Universidad de Cambridge, quien en "Sesenta millones de romanos..." estudia y caracteriza la cultura popular como un conjunto de estrategias empleadas por el pueblo romano para enfrentar los desafíos de la vida cotidiana

Bulletin of the Museum of Comparative Zoology at Harvard College.

v.109 (1953)