Simulation study of spinal cord stimulation evoked compound action potential / 生物医学工程学杂志

Spinal cord stimulation (SCS) for pain is usually implanted as an open loop system using unchanged parameters. To avoid the under and over stimulation caused by lead migration, evoked compound action potentials (ECAP) is used as feedback signal to change the stimulating parameters. This study established a simulation model of ECAP recording to investigate the relationship between ECAP component and dorsal column (DC) fiber recruitment. Finite element model of SCS and multi-compartment model of sensory fiber were coupled to calculate the single fiber action potential (SFAP) caused by single fiber in different spinal cord regions. The synthetized ECAP, superimposition of SFAP, could be considered as an index of DC fiber excitation degree, because the position of crests and amplitude of ECAP corresponds to different fiber diameters. When 10% or less DC fibers were excited, the crests corresponded to fibers with large diameters. When 20% or more DC fibers were excited, ECAP showed a slow conduction crest, which corresponded to fibers with small diameters. The amplitude of this slow conduction crest increased as the stimulating intensity increased while the amplitude of the fast conduction crest almost remained unchanged. Therefore, the simulated ECAP signal in this paper could be used to evaluate the degree of excitation of DC fibers. This SCS-ECAP model may provide theoretical basis for future clinical application of close loop SCS base on ECAP.

The role of computer simulation models in the design of public policies / El rol de los modelos de simulación por computadora en el diseño de políticas públicas

Abstract Cardiovascular diseases are the number one cause of death globally, but their optimal prevention remains a challenge. A high-risk approach can only have a limited effect at a population level, while population-based strategies can improve and extend the coverage of a high-risk approach. However, one main problem for promoting cardiovascular diseases prevention public policies is the difficulty to foresee population health benefits of a single policy. Computer simulation models can assist with this problem, due to their ability to estimate intervention effects over different periods, and by scaling up the evidence to a broader, more diverse population. Their applicability to countries with different social, political and economic contexts can assist in the design of public policies. There are several models that assess health and economics scenarios, but regardless which model is chosen, when adequately used, they can provide reasonable estimations of health policies' impact. There is a growing consensus amongst the public health communities about the powerful role of population-level policies. They are more effective, cost saving and more equitable when compared with individual-level interventions. Policy makers and the public health community need to make further progress in changing the focus of prevention, from individuals to populations.

Resumen Las enfermedades cardiovasculares son la principal causa de muerte en el mundo, pero su prevención óptima sigue siendo un desafío. El enfoque prioritario a escala individual en pacientes de alto riesgo solo puede tener un efecto limitado a nivel colectivo, mientras que las estrategias de alcance poblacional pueden mejorar y ampliar la cobertura de estos enfoques de alto riesgo. Sin embargo, uno de los principales problemas para promover políticas públicas de prevención de enfermedades cardiovasculares es la dificultad para prever los beneficios que una política única puede tener en salud. Los modelos de simulación por computadora pueden ayudar con este problema, dada su capacidad para estimar los efectos de una intervención en diferentes períodos, ampliando la evidencia a una población más extensa y diversa. Adicionalmente, su aplicabilidad a países con diferentes contextos sociales, políticos y económicos puede asistir en el diseño de políticas públicas. Existen varios modelos que evalúan escenarios tanto de salud como de economía, pero independientemente de qué modelo se elija, usados adecuadamente pueden proporcionar estimaciones razonables del impacto de las políticas de salud. Existe un consenso creciente en el ámbito de la salud pública sobre el importante rol de las políticas poblacionales. Son más efectivas, económicas, y equitativas en comparación con las intervenciones a nivel individual. En la formulación de políticas públicas en general, y de salud pública en particular, se debe avanzar en cambiar el enfoque de la prevención desde las personas a las comunidades.

Stock assessment of the peacock bass Cichla temensis (Humboldt, 1821), an important fishing resource from the middle Negro river, Amazonas, Brazil / Avaliação de estoque do tucunaré Cichla temensis, um importante recurso pesqueiro do médio rio Negro, Amazonas, Brasil

Abstract Peacock bass Cichla temensis is an important species at the Amazon basin, since commercial, subsistence and recreational fisheries simultaneously exploit it. Cichla temensis is the preferred species by recreational fishers and it has been strongly exploited, mainly at the Negro river, the second largest tributary of the Amazon River. It was used data from experimental fisheries, collected at the middle stretch of Negro river, which were coupled with previously published data on its population dynamics, to run a yield per recruit model and build scenarios of sustainable fisheries. The results showed that the age of the first catch is a key variable to successful management of the peacock bass stocks at this region.

Resumo O tucunaré Cichla temensis é uma importante espécie de peixe da bacia Amazônica, uma vez que esta espécie é simultaneamente explotada pela pesca comercial e de subsistência. Além disso, é preferida pelos pescadores esportivos que atuam na região do rio Negro, o segundo maior afluente do rio Amazonas. Foram usados dados de pescarias experimentais, coletados no trecho médio do rio Negro. Estes dados foram vinculados a outros dados, previamente publicados, sobre sua dinâmica populacional, para executar um modelo de rendimento por recruta e, dessa forma, construir cenários para pesca sustentável dessa espécie. Os resultados mostraram que a idade da primeira captura é uma variável chave para gerenciar, com sucesso, os estoques de tucunarés nesta região.

Impact of Two Distinct Dental Anesthesia Simulation Models on the Perception of Learning by Students / Impacto de dos distintos modelos de simulación para anestesia dental en la percepción del aprendizaje en estudiantes

ABSTRACT We evaluated an infiltration anesthesia simulation model (IAM) and a conduction anesthesia simulation model (CAM) on the perception of learning by Mexican dental students. Our aim was to compare the perception of learning by dental students trained with two distinct dental anesthesia simulation model (DASM) with dental students who were not trained with a DASM. 3 groups participated in the study: G1 (N=12 students) learned to block the mental nerve (BMN) by participating in a theoretical lecture (stage 1) and a clinical demonstration (stage 2); G2 (N=12 students) learned the BMN by participating in the stage 1, stage 2, and training with the CAM; G3 (N=12 students) learned the BMN by participating in the stage 1, stage 2, and training with the IAM. The groups performed the BMN in a clinical exercise. Working-time of all participants was timed. Perception of learning for all participants was evaluated with a 5-point Likert Scale. The results showed that statistically significant differences were found between score of G1 and score of G2 and score of G3 (P<0.05). No statistically significant differences were found between scores of G2 and scores of G3. G1, G2 and G3 showed an average working-time of 12:42 minutes, 9.75 minutes and 8:03 minutes, respectively (P<0.05). We concluded that the IAM and CAM showed a positive impact on the perception of learning, and the students trained with the IAM showed a shorter working time compared with the students trained with the CAM.

RESUMEN En este estudio se evaluó el impacto de un modelo de simulación de anestesia dental por infiltración (IAM) y de un modelo de simulación de anestesia dental por bloqueo (CAM) en la percepción del aprendizaje en estudiantes mexicanos en estomatología. El objetivo fue comparar la percepción en el aprendizaje de estudiantes que entrenaron empleando dos distintos modelos de simulación de anestesia dental con estudiantes que no recibieron entrenamiento empleando algún modelo de simulación de anestesia dental. Participaron 3 grupos en el estudio: G1 (n=12) aprendieron el bloqueo del nervio mentoniano (BNM) al participar en una clase teórica (sesión 1) y en una demostración clínica (sesión 2); G2 (n=12) aprendieron la técnica de anestesia del BNM al participar en la sesión 1, sesión 2 y entrenando con el CAM; G3 (n=12) aprendieron la técnica del BNM al participar en la sesión 1, sesión 2 y entrenando con el IAM. Los grupos aplicaron la técnica del BNM en un ejercicio clínico. Se midió el tiempo de trabajo de los participantes. La percepción del aprendizaje de los participantes se evaluó con una Escala de Likert de 5 ítems. Los resultados mostraron diferencias estadísticamente significativas entre los valores del G2 y del G3 en comparación con el G1. No se encontraron diferencias estadísticas entre los valores del G2 y del G3. El tiempo de trabajo para el G1, G2 y G3 fue respectivamente de: 12:42 minutos, 9.75 minutos y 8:03 minutos, (P<0.05). Se concluyó que el IAM y el CAM mostraron un impacto positivo en la percepción del aprendizaje; los estudiantes entrenados con el IAM mostraron un tiempo de trabajo más corto en comparación con los estudiantes entrenados con el CAM.

Tecnologías de la información y comunicación en el desarrollo de modelos estocásticos aplicados al sector de la salud / Information and communication technologies in the development of stochastic models applied to the health sector

Un modelo estocástico de simulación permite estudiar y represen tar de manera simplificada el comportamiento de variables complejas en términos de probabilidad. En este contexto, el objetivo de este trabajo es presentar, a través del uso de herramientas de tecnologías de la información y comunicación, la aplicabilidad de modelos y métodos de simulación, en estudios de indicadores dentro del sector de la salud. A través del desarrollo de un caso de estudio, este trabajo demuestra el potencial de las herramientas tecnológicas @Risk y Excel en la construcción de modelos estocásticos que permiten a los profesionales de la salud predecir, monitorizar y dar soporte en la toma de decisiones en el tratamiento y seguimiento de indicadores e índices de una población.

A stochastic simulation model allows to study and represents in a simplified manner the behavior of complex variables in terms of probability. In this context, the objective of this work is to present, through the use of information and communication technology tools, the applicability of simulation models and methods, in studies of indicators within the health sector. Through the development of a case study, this work demonstrates the potential of the @Risk and Excel technological tools in the construction of stochastic models that allow health professionals to predict, monitor and support decision making in the treatment and monitoring of indicators and indices of a population.

Construction of theoretical model of traditional Chinese medicine intelligent manufacturing / 中国中药杂志

In the process of transforming and upgrading of traditional Chinese medicine( TCM) intelligent manufacturing,the TCM enterprises lack systematic and in-depth research on intelligent manufacturing of TCM,leading to insufficient understanding of relevant concepts,development direction,development content and other aspects,to some extent,causing fuzzy and chaotic phenomena. The theoretical model,as a higher expression level of scientific thinking,has the function of interpretation and prediction,and can provide theoretical basis as well as guide for scientific research. Therefore,this article aims to construct a theoretical model of TCM intelligent manufacturing based on the concept of flexible production and intelligent equipment for some unhealthy phenomena in the development process of TCM intelligent manufacturing. In the TCM intelligent manufacturing system,with theory model as the core,the new-generation information technology was integrated with the TCM manufacturing technology to realize the integration of informationization and industrilization as well as the landing of theoretical model. Then,a 3 D simulation model was established to provide a visual environment for intelligent manufacturing of TCM and simulate the virtual reality throughout the TCM intelligent manufacturing process. The new theoretical model in this paper,to a certain extent,can play a guiding role in the development of TCM intelligent manufacturing,and can also provide reference for the realization of TCM intelligent manufacturing.

A single compartment simulation model of pharmacokinetics

For better understanding about derivation of various parameters related to pharmacokinetics, this model is developed. Animals or human volunteers are not used in this model but the principles used in pharmacokinetic studies in volunteers are incorporated. There is detailed description about setting of the model and derivation of various parameters step by step. An example is followed to illustrate the calculations involved. Possibilities of further extension of model to derive additional parameters and variations are discussed. The experience indicates that the model serves as a good demonstration to undergraduate students and a meaningful experiment for PG-students for learning and as a practical-examination exercise. The purpose of the article is to widen the use of this simple teaching tool at various centers.

The robot-assisted system YunSRobot for soft endoscopy: a trial of remote manipulation on simulation models / 中华内科杂志

Objective To evaluate the feasibility and safety of the robot - assisted system YunSRobot for remote manipulation endoscopy. Methods When the master of YunSRobot was installed in the gastroenterology office in Chinese PLA General Hospital, the robot slave and upper gastrointestinal simulation model (Takahashi Lm103,Japan) were installed at the same time in the State Key Laboratory of Robotics, Shenyang Institute of Automation. Three physicians were trained to operate the master robotics and performed gastroscopy on the simulation model based on network cloud. Each physician performed 3 procedures of oesophagogastroduodenoscopy (EGD) by YunSRobot using traditional manual endoscopy, on-site operating mode, and remote manipulation mode, respectively. The operating time, lumenal anatomic exposure,man-machine interaction and other parameters were recorded. Results The number of standard pictures obtained by traditional manual endoscopy group, on-site operating group and remote manipulation group were 39.9±0.3, 39.8±0.4, 39.9±0.3, respectively. The images of all five lesions could be obtained by each operation. The operating time in the duodenum of remote group was longer than that of on-site group, with average time (78.2±16.0)s vs. (68.9±15.8)s (P=0.021) respectively. As to the operating time on other parts or total time, all three groups were comparable. Although there was a mean delay of (572.1±48.5) ms in remote operation group, the operation was still smooth. However, compared with on-site group, the percentage of clear view time in the duodenum was significantly shortened in remote group: [(77.8±8.2)% vs. (83.9 ± 6.4)% , P=0.024]. Statistically significant difference was detected in percentage of clear view time neither in other sites, nor was in the total operating time between two groups. The operating time in each part of remote group was obviously longer than that of manual group as followings, pharyngeal (27.3±4.2) s vs. (9.2±1.3)s (P<0.001), esophageal (29.7±6.4)s vs. (19.3±1.6)s (P=0.004), stomach (56.7±17.0)s vs. (40.3±7.0)s (P=0.003), pylorus (20.2±5.5)s vs. (9.3±1.3)s (P<0.001), duodenum (78.2±16.0)s vs. (29.3±5.6)s (P<0.001). Thus the total operating time was also longer in remote group as (559.0±87.2)s vs. (253.1±16.6)s (P<0.001). The respective time in pharynx, esophagus, stomach, pylorus, duodenum, or the overall time was all longer in remote group than that in manual group. Conclusions The soft endoscopy robot YunSRobot has satisfactory safety and stability. Remote upper gastrointestinal endoscopy can be completed based on common network and an endoscope simulation model with smooth operation. The inspection time by YunSRobot robot per part and the overall time are longer than those of manual operation on site, still, remote operating time meets the standard of upper gastrointestinal endoscopy.

Alineación Estática de Prótesis a través de Variables Cinéticas y Métodos de Aprendizaje de Máquina / Static Alignment of Prosthetics using Kinetic Variables and Machine Learning Methods

El proceso complejo de la alineación en las prótesis y la no existencia de un modelo predictivo para alineación estática de prótesis transtibiales es el foco de esta investigación.Objetivo: Obtener un modelo computacional que permita establecer la existencia de la alineación estática de prótesis transtibiales a través de parámetros cinéticos presentes en amputados transtibiales unilaterales. Métodos: Se realizó la construcción de una base de datos de valores de Centro de Presión (COP) y distribución de presión plantar en amputados medidos en el Servicio de Amputados y Prótesis del Hospital Militar Central, Bogotá, Colombia. Los datos incluyen valores cinéticos medidos con la prótesis en alineación y en desalineación. Resultados: Se desarrollaron tres modelos computacionales, una red neuronal, una máquina de soporte vectorial y un árbol de decisión, se realizó la comparación del desempeño de los modelos. Conclusiones: Los modelos que hacen uso de máquinas de soporte vectorial y de árboles de decisión tuvieron mayor desempeño que la red neuronal. De esta forma, se comprueba que la alineación estática se puede llevar a cabo de forma objetiva empleando recursos tecnológicos(AU)

The complex process of alignment in prosthesis and the non-existence of a model for static alignment of transtibial prostheses is the focus of this research. Objective: Obtain a computational model to establish the existence of the static alignment of transtibial prostheses through kinetic parameters present in unilateral transtibial amputees. Methods: In the Amputee and Prosthetic Service of the Central Military Hospital, Bogotá, Colombia, the construction of a data base of Pressure Center (COP) and distribution of plantar pressure in amputees was carried out. The data include kinetic values ​​measured with the prosthesis in alignment and misalignment. Results: Three computational models were developed, a neural network, vector support machines and decision trees, the performance of the models was compared. Conclusions: Models that make use of vector support machines and decision trees had higher performance than the neural network. In this way, it is verified that the static alignment can be carried out objectively using technological resources(AU)

Poloxamer 407 Hydrogels for Intravesical Instillation to Mouse Bladder: Gel-Forming Capacity and Retention Performance

PURPOSE: Poloxamer 407 (P407) thermo-sensitive hydrogel formulations were developed to enhance the retention time in the urinary bladder after intravesical instillation. MATERIALS AND METHODS: P407 hydrogels (P407Gels) containing 0.2 w/w% fluorescein isothiocyanate dextran (FD, MW 4 kDa) as a fluorescent probe were prepared by the cold method with different concentrations of the polymer (20, 25, and 30 w/w%). The gel-forming capacities were characterized in terms of gelation temperature (G-Temp), gelation time (G-Time), and gel duration (G-Dur). Homogenous dispersion of the probe throughout the hydrogel was observed by using fluorescence microscopy. The in vitro bladder simulation model was established to evaluate the retention and drug release properties. P407Gels in the solution state were administered to nude mice via urinary instillation, and the in vivo retention behavior of P407Gels was visualized by using an in vivo imaging system (IVIS). RESULTS: P407Gels showed a thermo-reversible phase transition at 4℃ (refrigerated; sol) and 37℃ (body temperature; gel). The G-Temp, G-Time, and G-Dur of FD-free P407Gels were approximately 10℃–20℃, 12–30 seconds, and 12–35 hours, respectively, and were not altered by the addition of FD. Fluorescence imaging showed that FD was spread homogenously in the gelled P407 solution. In a bladder simulation model, even after repeated periodic filling-emptying cycles, the hydrogel formulation displayed excellent retention with continuous release of the probe over 8 hours. The FD release from P407Gels and the erosion of the gel, both of which followed zero-order kinetics, had a linear relationship (r²=0.988). IVIS demonstrated that the intravesical retention time of P407Gels was over 4 hours, which was longer than that of the FD solution ( < 1 hour), even though periodic urination occurred in the mice. CONCLUSIONS: FD release from P407Gels was erosion-controlled. P407Gels represent a promising system to enhance intravesical retention with extended drug delivery.

Stock assessment of the peacock bass Cichla temensis (Humboldt, 1821), an important fishing resource from the middle Negro river, Amazonas, Brazil

Abstract Peacock bass Cichla temensis is an important species at the Amazon basin, since commercial, subsistence and recreational fisheries simultaneously exploit it. Cichla temensis is the preferred species by recreational fishers and it has been strongly exploited, mainly at the Negro river, the second largest tributary of the Amazon River. It was used data from experimental fisheries, collected at the middle stretch of Negro river, which were coupled with previously published data on its population dynamics, to run a yield per recruit model and build scenarios of sustainable fisheries. The results showed that the age of the first catch is a key variable to successful management of the peacock bass stocks at this region.

Resumo O tucunaré Cichla temensis é uma importante espécie de peixe da bacia Amazônica, uma vez que esta espécie é simultaneamente explotada pela pesca comercial e de subsistência. Além disso, é preferida pelos pescadores esportivos que atuam na região do rio Negro, o segundo maior afluente do rio Amazonas. Foram usados dados de pescarias experimentais, coletados no trecho médio do rio Negro. Estes dados foram vinculados a outros dados, previamente publicados, sobre sua dinâmica populacional, para executar um modelo de rendimento por recruta e, dessa forma, construir cenários para pesca sustentável dessa espécie. Os resultados mostraram que a idade da primeira captura é uma variável chave para gerenciar, com sucesso, os estoques de tucunarés nesta região.

Establishment of a simulation model for mandibular third molar extraction / 实用口腔医学杂志

Objective:To establish a model of mandibular impact third molar extraction with common dental materials for pre-clinical trai-ning.Methods:Based on the characteristics of the common dental materials,the anatomy and extraction skill of mandibular impact third molar,the dental model for mandibular impact third molar extraction was designed and made.Then,this dental model was placed in the head-simulation model as required,and used by the dentists and the students.The questionnaire was designed and used to evalu-ate the effects of the model.Results:A new method of designing and making a dental model for mandibular impact third molar extraction with the common dental materials was established successfully.The questionnaire results showed that all the dentists and students agreed that this model could simulate the mandibular third molar extraction procedure.Conclusion:Simulation model of the mandibular third molar extraction can help students for the following clinical practice.

Costo-efectividad del uso de la Vareniclina versus las alternativas existentes para la cesación del fumado usando el modelo BENESCO en la población adulta costarricense / Cost-effectiveness of Varenicline versus all interventions for quitting smoking cessation in the adult population of Costa Rica using the BENESCO model

El uso del tabasco es uno de los problemas de salud más serios a nivel mundial y es una adicción prevenible, por esto, la disponibilidad de tratamientos para dejar de fumar representa grandes beneficios tanto para la salud individual como para el sistema institucional. Ante la utilización de nuevos tratamientos, en especial la vareniclina, se deben evaluar comparativamente las alternativas disponibles en Costa Rica, ya que no hay claridad en cuál es la mejor opción terapéutica y cuál genere una mejor relación de costo-efectividad. El objetivo de este estudio fue modelar la razón costo-efectividad de las diferentes opciones terapéuticas en la cesación del tabaquismo disponibles en Costa Rica utilizando el modelo BENESCO. Métodos: se utilizó el modelo BENESCO para simular la morbilidad y la mortalidad de la población de fumadores costarricenses de ambos sexos entre los 18 y 99 años de edad...

Application of a new simulation model of infant cleft lip in surgery simulation and teaching of lip repair / 实用口腔医学杂志

Objective:To establish a new method of designing and fabricating a facial simulation model of infant cleft lip for lip repair simulation and surgery teaching. Methods: Using latest three-dimensional scanning, reversed engineering and rapid prototyping techniques to fulfill the individual design and rapid auto-manufacture for the facial model of the cleft lip infants. With the new chromatosis technique and special silicone material of Maxillofacial Prosthetics the simulative face of infant cleft lip were fabricated. The new simulation model was used for lip repair surgery teaching. Results: The vivid faical data was successfully acquired by scanner and then designed by software. The solid plastic partern of patient's face was fabricated by machine, which was eventually replaced by maxillofaical silicon. The surgeon applied it for pre-surgery simulation and surgery teaching. Conclusion: This study successfully designed and fabricated the new simulation model of cleft lip infant's face, which can be a ideal training model for lip repair surgery teaching.

Study on the spread of influenza A (H1N1) under community based simulation model / 中华流行病学杂志

A simulation experiment was carried out by applying the simulation model to spread of influenza A (H1N1) in communities with different population density. Population at the community-level was divided into susceptible, infected and recovered ones, according to the susceptive-infective-removal (SIR) model, and the age structure of the population was set on the basis of data from the Fifth Population Census. Contact and moving of the individuals were based on the Network Random Contact Model and the mortality and infection mode were established in line with the influenza A (H 1N 1) medical description. The results of an example analysis showed that the infection rate was closely related to the density of the community-based population while the rate on early infection grew rapidly. Influenza A (H1N1) seemed more likely to break out in the community with population density of over 50/hm2. Comparative tests showed that vaccination could effectively restrain the spread of influenza A (H1N1) at the community level. Conclusion Population density,and the coverage of influenza vaccination were risk factors for influenza A (H1N1) epidemics.Results of the experiment showed of value, for prevention and vaccination on this topic.

Research of Modeling and Simulation for Light-algae Bioreactor in BLSS / 航天医学与医学工程

Objective To study mathematical model and to perform computer simulation for an important subsystem in the bioregenerative life support system(BLSS),i.e.,light-algae bioreactor(LABR)forcontinuously cultivating green microalgae andsignificantly maintaining life support function of BLSS.MethodsBased on the theories of system dynamics and stoichiometry,the mathematical model and simulation model of LABR were respectively established with experimental data,and then computer experiments were conducted to simulate dynamic responses of LABR under different parameters as well as their combinations.Results It was shown that the kinetic model of LABR was valid for its real-life counterpart by a series of verification tests.It could reliably and beneficially provede technical and methodologcal helps for further investigations of LABR,such as theoretical analysis,design,control and optimization,and so on.Conclusion With computer experiments based on mathematical model and simulation model,it decreases much more in time and money consumption for investigations than with real experiment.This method can also be extended to use in other subsystems studies of BLSS.

Modelo empírico para estimar o preço da carcaça bovina pago pelo consumidor / Empirical model to estimate beef carcass price paid by the consumer

Este trabalho teve como objetivo o desenvolvimento de um modelo que possa ser utilizado para facilitar a obtenção do preço do quilo de carcaça pago pelo consumidor. Com os dados coletados por levantamento mensal do preço dos diferentes cortes de carne em quatro supermercados de Santa Maria, durante o ano de 2005, foi gerado um modelo empírico para a obtenção do preço da carcaça pago no varejo. O modelo gerado permite estimar o valor do quilo de carcaça pago pelo consumidor a partir do preço de dois cortes praticados no varejo (Maminha e Coxão mole). Como o consumidor é o formulador final do preço, pode-se estimar os valores pecuniários apropriados por cada elo da cadeia, facilitando a negociação entre as partes envolvidas no negócio.

The aim of this study was to obtain a model that makes it easier to estimate the price paid per kilogram of carcass at consumer level. Thus, with the collected monthly data of meat cut prices in four supermarkets in the city of Santa Maria, during the year of 2005, an empirical model was made to estimate the price paid per kilogram of carcass. The model generated allows the estimation of prices paid per kilogram of carcass at consumer level for two cuts (Tail of Rump and Topside Cap On). Since the consumer determines the final value of the chain, it is possible to estimate the percentage that each component holds, which facilitates negotiation among these components.

Construction of microsimulation model of urban employees' medical insurance in Kunming city / 第二军医大学学报

Objective:To discuss the application of microsimulation model in forecasting the change of medical insurance risk-pooling fund in Kunming city.Methods: Taking the SAS8.2 software as the platform,we constructed a microsimulation model for urban employees' medical insurance in Kunming city using computer simulation technology and ARENA simulation software.Results: The construction process included 4 steps:(1) to confirm the simulation object;(2) to construct the micro data file;(3) to design the system and to program;(4) to run the program and forecast the result.The system mainly consisted of population status module,action module and policy module.Conclusion: The present model complies with the latest type distribution of employees in Kunming,and its simulation result can reflect the effectiveness of medical insurance policy in recent years.

A Study on the Efficient Management of Long-term Inpatient Flow in a General Hospital / 예방의학회지

This study refers to the problem of long-term inpatient flow in a general hospital. In this study, a queueing simulation model was developed for the two departments in the hospital with a homogenous case mix and relatively many long-term inpatients in order to increase the tumover rate and hospital charges. Before the simulation run, the model was verified by the Kolmogorov-Smirmov test. The following results were generated by three alternative models of the special bed policies. 1. Alternative I: When long term inpatients were admitted to the wards belonging to departments A and B without transfer to other departments and special beds, the average turn-over rate decreased by 2-4% and the average hospital charges decreased by 70 million won. 2. Alternative II: When long-term inpatients were transferred to department C but the transfer of wards was determined by department C in order of clinical need, the average turnover rate increased by 4-13% but the average hospital charges decreased by 30 million won. This result was not greatly different from the present state. 3. Alternative III: When long-term inpatients were transferred to the special wards and department C simultaneously, the increase in the average turnover rate and hospital charges was equivalent to the increase of two beds in the special wards. When the special wards were allocated 16 beds, the average turnover rate of departments A and B increased by about 55% and 20% respectively. Also, the hospital charges increased by about 0.44 billion won. As a result, trasfer to department C and the use of 16 beds in the special wards for long-term inpatients of departments A and B is expected to maximize the hospital revenue. However, as the above special bed policy can not increase the turnover rate above 60%, there is a need for a more comprehensive policy to further increase the rate. The development of an elaborate model should include the number of long-term inpatients in all clinical departments, the special wards system or an increase of hospital beds to handle admission needs, and the resources of the hospital by department. When the alternative are evaluated, a cost-benefit analysis in addition to the turnover rate and the hospital charges should be considered.