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L'inici del programa de detecció precoç del càncer de mama en els districtes de Ciutat Vella i Sant Martí de la ciutat de Barcelona, va motivar la realització del primer estudi en el barri de la Barceloneta, amb l'objectiu d'analitzar diferents factors associats a la participació. La resposta després de la primera citació ha estat del 65%. S'ha relacionat amb l'historial clínic previ augmentant en quasi 4 vegades l'ods de resposta, i amb el receptor de la carta de citació, variant del 75% quan és la mateixa interessada fins el 47% quan la carta és dipositada a la bústia, i el 32% quan l'adreça és insegura. La resposta després de les citacions successives ha estat del 26%. S'ha relacionat amb l'historial clínic previ augmentant en quasi 8 vegades l'ods de resposta, i amb la raó de no haver vingut després de la primera citació, passant del 50% quan és circumstancial fins el 11% quan s'atribueix a manca d'interès. La taxa de cobertura (79%) disminueix amb l'edat, i augmenta amb el nivell educatiu.El segon estudi permet apreciar com prèviament al programa les mamografies no s'adequaven a les directrius europees. Un 59% de les dones entrevistades dels barris El Clot, Camp de l'Arpa i La Verneda, s'han fet una mamografia de cribratge en els últims quatre anys. Existeix una major utilització en dones més joves, de major nivell educatiu i que tenen historial clínic. La periodicitat era anyal en un 35%, biennal en un 38% i cada 2-4 anys en el 27% restant. El 58% de les mamografies s'han realitzat en la sanitat pública, que mostra el major percentatge (42%) de periodicitat biennal. En les dones participants, la visita al ginecòleg i la pràctica de citologia uterina han presentat la major associació (probabilitats 4 vegades superiors) amb la mamografia prèvia de cribratge. També s'han associat a una major utilització els antecedents personals de patologia mamària i familiars de càncer de mama, l'autoexploració mamària i la visita mèdica recent, mentre que l'autopercepció de salut ha presentat una relació inversa.Finalment, el tercer estudi és un assaig controlat aleatoritzat on s'han comparat tres diferents estratègies utilitzades per a invitar dones d'entre 50 a 64 anys a participar en el programa. L'estratègia del contacte directe incrementa de forma significativa fins un 22% la probabilitat de resposta després de la primera citació en les dones del barri de Raval Nord invitades. En el grup de contacte directe aquesta resposta era del 63%, comparat amb un 55% quan la carta era enviada pels professionals sanitaris del CAP, i un 52% quan era remesa pels responsables del programa. Aquest increment en el grup de contacte directe s'observa encara que sols s'ha aconseguit contactar en un 45% dels casos directament amb la mateixa dona. Quan aquest fet s'assoleix la resposta és del 72%. La utilització de professionals no sanitaris per a aconsellar les dones sembla ser una estratègia efectiva, particularment entre les dones de baix nivell educatiu. / The beginning of the breast cancer screening program in the Ciutat Vella and Sant Martí districts of Barcelona was the origin of the first study in the Barceloneta quarter, with the aim of analyzing different factors related to participation. The response after the first citation was 65%. Having a previous clinical history, increased in nearly 4 times the response odds. Response after the first citation was influenced by who the recipient of the citation letter was, ranging from 75% when this was the same person concerned to 47% when the letter was left in the letter-box, and to 32% when the address was uncertain. The response after subsequent citations was 26%. Having previous clinical history increased the response odds in almost 8 times. The response after successive citations, ranged from 50% when it was for circumstantial reasons, to 11 % when it was due to lack of interest. Coverage rate (79%) decreased with age, and increased with education level.The second study shows that, previously to the program, mammography screening did not comply with European guidelines. A screening mammography had been performed on 59 % of women interviewed in the El Clot, Camp de l'Arpa and La Verneda quarters. The utilization of mammography was higher among younger women, women with a higher education level, or who had previous visits to a physician. Periodicity was once a year in 35% of cases, once every two years in 38%, and every 2-4 years in the remaining 27 %. Mammographies were performed at the Public Heath Service in 58 % of cases. The Public Health Service shows the highest percentage (42 %) of biennial periodicity. The variables more strongly associated with the use of screening mammography (probabilities 4 times higher) were: visit to a gynecologist and performance of a pap smear. Also related to the utilization of screening mammography were: personal history of breast pathology, family history of breast cancer, breast self-examination, and recent visit to a general practitioner. Self-perceived health presented an inverse relation with screening mammography use.Finally, the third study is a randomized controlled trial where three different strategies of inviting 50 to 64 years old women to participate in the program were compared. The strategy of direct contact increased in a significant way, up to 22%, the possibility of response after the first citation among women invited in the Raval Nord quarter. The response rate in the direct contact group was 62%, compared to 55% when the letter was sent by Primary Health Care Team, and 52% when it was sent by those responsible of the program. This increase in the direct contact group is noticeable even though only in 45 % of cases it was possible to contact the subject herself. When this was achieved, response raised to 72%. Use of non-health professionals to advise women seems to be an effective strategy, especially among women with a lower educational level.

Multiple criteria decision analysis (MCDA) techniques are developed to address challenging classification problems arising in engineering management and elsewhere. MCDA consists of a set of principles and tools to assist a decision maker (DM) to solve a decision problem with a finite set of alternatives compared according to two or more criteria, which are usually conflicting. The three types of classification problems to which original research contributions are made are <ol> <li>Screening: Reduce a large set of alternatives to a smaller set that most likely contains the best choice. </li> <li>Sorting: Arrange the alternatives into a few groups in preference order, so that the DM can manage them more effectively. </li> <li>Nominal classification: Assign alternatives to nominal groups structured by the DM, so that the number of groups, and the characteristics of each group, seem appropriate to the DM. </ol> Research on screening is divided into two parts: the design of a sequential screening procedure that is then applied to water resource planning in the Region of Waterloo, Ontario, Canada; and the development of a case-based distance method for screening that is then demonstrated using a numerical example. <br /><br /> Sorting problems are studied extensively under three headings. Case-based distance sorting is carried out with Model I, which is optimized for use with cardinal criteria only, and Model II, which is designed for both cardinal and ordinal criteria; both sorting approaches are applied to a case study in Canadian municipal water usage analysis. Sorting in inventory management is studied using a case-based distance method designed for multiple criteria ABC analysis, and then applied to a case study involving hospital inventory management. Finally sorting is applied to bilateral negotiation using a case-based distance model to assist negotiators that is then demonstrated on a negotiation regarding the supply of bicycle components. <br /><br /> A new kind of decision analysis problem, called multiple criteria nominal classification (MCNC), is addressed. Traditional classification methods in MCDA focus on sorting alternatives into groups ordered by preference. MCNC is the classification of alternatives into nominal groups, structured by the DM, who specifies multiple characteristics for each group. The features, definitions and structures of MCNC are presented, emphasizing criterion and alternative flexibility. An analysis procedure is proposed to solve MCNC problems systematically and applied to a water resources planning problem.

In the rst part of this thesis we discuss some details of properties of graphene and we explain the tight-binding approach to nd the energy spectrum in graphene. In the second part of the thesis, we solve a nonlinear integral equation for the electrostatic potential in doped graphene due to an external charge, arising from a Thomas-Fermi (TF) model for screening by graphene's electron bands. In particular, we study the e ects of a nite equilibrium charge carrier density in graphene, non-zero temperature, non-zero gap between graphene and a dielectric substrate, as well as the nonlinearity in the band density of states. E ects of the exchange and correlation interactions are also brie y discussed for undoped graphene at zero temperature. Results from the nonlinear model are compared with results from both the linearized TF model and the dielectric screening model within the random phase approximation (RPA). In addition, the image potential of the external charge is evaluated from the solution of the nonlinear integral equation and compared to the results of linear models. We have found generally good agreement between the results of the nonlinear TF model and the RPA model in doped graphene, apart from Friedel oscillations in the latter model. However, relatively strong nonlinear e ects in the TF model are found to persist even at high doping densities and large distances of the external charge.

Prostate cancer is the most commonly diagnosed cancer and the second leading cause of cancer death among men in the United States. In African American men, the disease is typically detected at a more advanced stage and mortality is twice the rate of Caucasian men. However, African American men are less likely to participate in prostate cancer screening. The purpose of this descriptive study was to assess the relationship between health beliefs, knowledge, and selected demographic variables (age, income and education) and a man’s decision to participate in prostate cancer screening among African American men dwelling in rural communities. The conceptual framework for the study was the Health Belief Model. Participants for the study were recruited through contacts within rural communities within west central Alabama. A convenience sample of 90 African American men between the ages of 40-82 years of age was recruited. Analysis of the research data indicated that there was a statistically significant difference in motivation (health belief), knowledge, and age of men who participated in prostate cancer screening compared to those who did not participate in prostate cancer screening. Forward logistic regression was used to determine which independent variables [health beliefs (benefits, barriers, motivation); knowledge; age; income; and education] were predictors of prostate cancer screening. Results indicated the overall model of one predictor, motivation, was statistically reliable in predicting prostate cancer screening participation among the rural dwelling men surveyed. The model accounted for 15 to 20% of the variance. The sensitivity of the model in predicting those who would participate in prostate cancer screening was 85%. The odds of those who would participate in prostate cancer screening were 1.3 times greater for each one unit increase in motivation. Results indicate a need for more educational and motivational interventions to promote informed decision making by African American men in regards to prostate screening activities. These interventions need to be culturally sensitive and geared toward African American men, specifically those living in rural areas.

Vision impairment is recognized as a global public health problem. Children are the most susceptible population to many of the vision diseases. Knowledge of the causes and prevalence of common types of visual impairments is important for planning of preventive health care services to ensure that the children receive proper eye care in a timely manner. The purpose of this thesis is to describe the prevalence of visual impairment and to identify associated risk factors among the prekindergarten children in Georgia. During August 2005 to May 2006, there were 30,115 prekindergarten children enrolled in the Prevent Blindness Georgia Children Vision Screening Program, and a total of 25,543 (84.8%) children received vision screening. A total of 1,345 (5.27%) children had visual impairments and were referred to take an eye exam. Over 80% of the children who were referred and received eye exams were found to have vision problems. Timely screening is one of the effective ways for early detection of vision problems among these children. This study showed there were significant differences in the screening rate between the children with high socioeconomic status and those with low socioeconomic status. Educational and promotion programs should focus on improving the knowledge of vision diseases and use of available preventive service, particularly by the community of low socioeconomic status.

Image based screening is an important tool used in research for development of drugs to fight cancer. Phase contrast video microscopy - a cheap and fast image screening technology - enables a rapid generation of large amounts of data, which requires a fast method for analysis of this data. As videos contain a lot of redundant information, the difficulty is to extract usable information in form of features from the videos, by compressing available information, or filter out redundant data. In this thesis, the problem is approached in an experimental fashion where three different methods have been devised and tested, to evaluate different ways to automatically extract features from phase contrast microscopy videos containing cultured cancer cells. The three methods considered are, in order: an adaptive linear filter, an on-line clustering algorithm, and an artificial neural network. The ambition is that outputs from these methods can create time-varying histograms of features that can be used in further mathematical modeling of cell dynamics. It is concluded that, while the results of the first method is not impressive and can be dismissed, the remaining two are more promising and are able to successfully extract features automatically and aggregate them into time-varying histograms.

Multiple criteria decision analysis (MCDA) techniques are developed to address challenging classification problems arising in engineering management and elsewhere. MCDA consists of a set of principles and tools to assist a decision maker (DM) to solve a decision problem with a finite set of alternatives compared according to two or more criteria, which are usually conflicting. The three types of classification problems to which original research contributions are made are <ol> <li>Screening: Reduce a large set of alternatives to a smaller set that most likely contains the best choice. </li> <li>Sorting: Arrange the alternatives into a few groups in preference order, so that the DM can manage them more effectively. </li> <li>Nominal classification: Assign alternatives to nominal groups structured by the DM, so that the number of groups, and the characteristics of each group, seem appropriate to the DM. </ol> Research on screening is divided into two parts: the design of a sequential screening procedure that is then applied to water resource planning in the Region of Waterloo, Ontario, Canada; and the development of a case-based distance method for screening that is then demonstrated using a numerical example. <br /><br /> Sorting problems are studied extensively under three headings. Case-based distance sorting is carried out with Model I, which is optimized for use with cardinal criteria only, and Model II, which is designed for both cardinal and ordinal criteria; both sorting approaches are applied to a case study in Canadian municipal water usage analysis. Sorting in inventory management is studied using a case-based distance method designed for multiple criteria ABC analysis, and then applied to a case study involving hospital inventory management. Finally sorting is applied to bilateral negotiation using a case-based distance model to assist negotiators that is then demonstrated on a negotiation regarding the supply of bicycle components. <br /><br /> A new kind of decision analysis problem, called multiple criteria nominal classification (MCNC), is addressed. Traditional classification methods in MCDA focus on sorting alternatives into groups ordered by preference. MCNC is the classification of alternatives into nominal groups, structured by the DM, who specifies multiple characteristics for each group. The features, definitions and structures of MCNC are presented, emphasizing criterion and alternative flexibility. An analysis procedure is proposed to solve MCNC problems systematically and applied to a water resources planning problem.

In the rst part of this thesis we discuss some details of properties of graphene and we explain the tight-binding approach to nd the energy spectrum in graphene. In the second part of the thesis, we solve a nonlinear integral equation for the electrostatic potential in doped graphene due to an external charge, arising from a Thomas-Fermi (TF) model for screening by graphene's electron bands. In particular, we study the e ects of a nite equilibrium charge carrier density in graphene, non-zero temperature, non-zero gap between graphene and a dielectric substrate, as well as the nonlinearity in the band density of states. E ects of the exchange and correlation interactions are also brie y discussed for undoped graphene at zero temperature. Results from the nonlinear model are compared with results from both the linearized TF model and the dielectric screening model within the random phase approximation (RPA). In addition, the image potential of the external charge is evaluated from the solution of the nonlinear integral equation and compared to the results of linear models. We have found generally good agreement between the results of the nonlinear TF model and the RPA model in doped graphene, apart from Friedel oscillations in the latter model. However, relatively strong nonlinear e ects in the TF model are found to persist even at high doping densities and large distances of the external charge.

The purpose of the present study was to construct and validate a brief screening instrument to support parent(s) and preschool/kindergarten teachers in monitoring and screening for cognitive impairment and/or delay in preschoolers. The target population of interest is all preschoolers <i>at-risk</i> for poor psychosocial and school outcomes due to chronic and acute dysfunction of the central nervous system (CNS). The accessible populations of interest to the present study are pediatric cancer survivors, preschoolers with alcohol related neurodevelopmental disorder (ARND), being preterm low birth weight, and/or diagnosed with various learning disabilities. The past practice of waiting until an <i>at-risk</i> child experienced poor school outcomes before being referred for cognitive assessment toward tailoring an intervention is no longer defensible. For the present study, a 61-item screening instrument (18 memory items, 19 verbal ability items, 15 attention items, and 9 demographic items) was pilot tested with parents, playschool teachers, and kindergarten teachers to rate preschoolers on overt behaviours associated with cognitive functioning. A criterion-referenced framework was used to establish a performance standard and set a cut score based on a sample of 151 normally functioning preschoolers aged 4:0- to 5:11-years. The various empirical and substantive analyses conducted resulted in a revised scale of 28 items (10 memory, 11 verbal ability, and 7 attention) titled, <i>Screening Test for the Early Prediction of School Success</i> (STEPSS). Given the need for a future study to validate the STEPSS with clinical groups of preschoolers, the screening instrument is intended to provide the empirical evidence needed to refer <i>at-risk</i> preschoolers for assessment with more comprehensive cognitive batteries. Constructing and validating the STEPSS is important for two reasons: 1) to fill a gap in the types of instruments available for monitoring and assessing cognitive functioning in <i>at-risk</i> preschool populations; and 2) to alleviate the current delay in targeting interventions for preschoolers because of the practice of depending upon the school system to monitor and identify poor cognitive functioning.