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The COVID-19 pandemic has inflicted substantial global morbidity and mortality since December 2019. This study endeavors to model the survival and cure rates of COVID-19 patients using advanced defective modeling techniques and leveraging sophisticated machine learning methods to enhance prediction accuracy. We applied a range of statistical approaches including parametric, semi-parametric, and non-parametric methods to fit established and novel models to COVID-19 survival data, with a particular focus on the Defective Gompertz Distribution. To our knowledge, this study rep- resents the pioneering use of defective modeling techniques for estimating cure rates in COVID-19 research. Farther more, we conducted a comparative analysis across different locations and countries using geographical and demographic data from our dataset. This exploration aimed to uncover variations in survival and cure rates influenced by factors such as socioeconomic status (SES), urban versus rural msilence, and healthcare accessibility. Our findings revealed significant disparities in survival and cure rates associated with demographic variables such as age, gender, SE S, urhanicity, and health- care access. Additionally, the study assessed the impact of various public health interventions and identified best practices implemented by different countries. Overall, our results contribute valuable insights to ongoing efforts aimed at comprehending and mitigating the anpact of COVID-19 through robust statistical and machine learning modeling techniques. These findings are crucial for informing public health policies and interventions worldwide. [ABSTRACT FROM AUTHOR]

Copyright of AIDS & Behavior is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Páginas de la Educación is the property of Universidad Catolica del Uruguay Damaso Antonio Larranaga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Whether prey species avoid predators and predator species track prey is a poorly understood aspect of predator–prey interactions, given measuring prey tracking by predators and predator avoidance by prey is challenging. A common approach to study these interactions among mammals in field situations is to monitor the spatial proximity of animals at fixed times, using GPS tags fitted to individuals. However, this method is invasive and only allows tracking of a subset of individuals. Here, we use an alternative, noninvasive camera-trapping approach to monitor temporal proximity of predator and prey animals. We deployed camera traps at fixed locations on Barro Colorado Island, Panama, where the ocelot (Leopardus pardalis) is the principal mammalian predator, and tested two hypotheses: (1) prey animals avoid ocelots; and (2) ocelots track prey. We quantified temporal proximity of predators and prey by fitting parametric survival models to the time intervals between subsequent prey and predator captures by camera traps, and then compared the observed intervals to random permutations that retained the spatiotemporal distribution of animal activity. We found that time until a prey animal appeared at a location was significantly longer than expected by chance if an ocelot had passed, and that the time until an ocelot appeared at a location was significantly shorter than expected by chance after prey passage. These findings are indirect evidence for both predator avoidance and prey tracking in this system. Our results show that predator avoidance and prey tracking influence predator and prey distribution over time in a field setting. Moreover, this study demonstrates that camera trapping is a viable and noninvasive alternative to GPS tracking for studying certain predator–prey interactions. [ABSTRACT FROM AUTHOR]

This article presents a survival analysis-based model to estimate the duration of the emotion of confusion in students during learning. Academic confusion can have both positive and negative effects, and its persistence can lead to negative emotions. The model considers crucial factors such as personality traits and students' prior knowledge, which have been shown to significantly influence the duration of confusion. To investigate this relationship, data were collected from seventh-grade students who used an intelligent tutoring system to solve algebra problems. The results of the analysis of data from 25 students revealed statistically significant differences in the duration of confusion based on different personality traits and prior algebra knowledge. Additionally, a model of intervention for intelligent learning environments was proposed when students are confused, based on the developed model. This module determines the optimal time to intervene and provide individualized assistance tailored to the student's knowledge for the specific problem. The study contributes to understanding the dynamics of academic confusion and highlights the importance of considering emotions and their duration, as well as personality traits and prior knowledge, when designing appropriate interventions in intelligent learning environments. Identifying the opportune moment to intervene when a student is confused is essential to promote a more effective learning process, allowing educators to adopt personalized approaches to meet individual students' needs and facilitate their learning journey. [ABSTRACT FROM AUTHOR]

Copyright of Revista Chilena de Derecho y Ciencia Política is the property of Revista Chilena de Derecho y Ciencia Política and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective/Context: This paper analyzes factors related to political incentives for public organizations to cease operations. It suggests that political turnover has a negative effect on the duration of these types of entities. However, this effect differs according to the size of the governing coalition. Methodology: Semi-parametric models and Cox regressions are used to estimate the survival of 415 public organizations in Colombia. Conclusions: The data show that a change in the presidential administration allows the new president to reshape the administration according to their interests. Data analysis also indicates that the larger the size of the government coalition, the lower the probability that a public entity will be eliminated. Originality: The article uses an original database containing longitudinal information on public organizations in Colombia for the period 1958 to 2020. This database contains 415 observations on the organizational characteristics of each entity. This paper contributes to the scarce literature on the termination of public organizations in Latin America. [ABSTRACT FROM AUTHOR]

Background: Stomach cancer is among the most frequent, is a leading cause of mortality in low- and middle-income countries. Assessing its survival is important to guide evidence-based health policies. Aims: To estimate stomach cancer survival in Colombia (2014-2019) with data from the National Cancer Information System (NCIS) and in Cali with data from the Cali Population Cancer Registry (RPCC) (1998-2017). Methods: NCIS estimated the overall 3-year net survival for 8,549 people, while RPCC estimated 5-year net survival for 6,776 people. Results: The 3-year net survival was 36.8% (95% CI: 35.5-38.1). Net survival was higher in people with special insurance (61.7%; 95% CI: 44.8-74.8) or third payer (40.5%; 95% CI: 38.7-42.3) than state insurance (30.7%; 95% CI: 28.7-32.8). It was also higher in women and people diagnosed at early stages. Multivariable analysis showed consistency with survival estimations with a higher risk of death in men, people with state insurance, and diagnosed at advanced stages. In Cali, the 5-year net survival remained stable in men during the last 20 years. In women the 5-year net survival in women increased 8.60 percentage points, equivalent to a 50% increase compared to the 1998-2002 period. For 2013-17, it was 19.1% (95%CI: 16.2-22.2) in men, and 24.8% (95% CI: 20.4-29.3) in women. Conclusions: Population survival estimates from the RPCC were lower than those observed in the NCIS. The differences in their methods and scope can explain variability. Nevertheless, our findings could be complementary to improve cancer control planning in the country. [ABSTRACT FROM AUTHOR]

From a panel of administrative data of contributors to the Argentine pension system, a survival analysis was carried out to compare the time in months until contributor status is lost for individuals who reach the minimum retirement age. The analysis involves two periods: one where the fully funded scheme was in force and the other with the pure pay‐as‐you‐go scheme in effect. It is observed that the survival curve of the contributor status during the second period is always above that in the first one, indicating that the probability of maintaining this status was always higher during the second period. Likewise, it was found that belonging to the cohort/group of the first period is significant in explaining the risk of losing contributor status, even controlling for other relevant variables. This result contrasts with the predictions of the World Bank about the best incentives that the fully funded scheme would generate for the supply of formal labor. Related Articles: Angelaki, Marina, and Leandro N. Carrera. 2015. "Radical Pension Reforms after the Crisis: A Comparative Analysis of Argentina and Greece." Politics & Policy 43(3): 378–400. https://doi.org/10.1111/polp.12117. Hazakis, Konstantinos J. 2015. "The Political Economy of Economic Adjustment Programs in the Eurozone: A Detailed Policy Analysis." Politics & Policy 43(6): 822–54. https://doi.org/10.1111/polp.12141. Jakee, Keith, and Keith Stacy. 2021. "Revisiting Pension Reform in Sweden: The Role of Corporatism (and Why it Matters)." Politics & Policy 49(3): 651–81. https://doi.org/10.1111/polp.12405. [ABSTRACT FROM AUTHOR]

Copyright of Dados - Revista de Ciências Sociais is the property of DADOS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective. To compare the survival of patients with chronic kidney disease (CKD) on hemodialysis (HD) versus peritoneal dialysis (PD). Materials and methods. Survival analysis of a retrospective cohort of patients ≥ 18 years who started HD versus PD at the Victor Lazarte Echegaray Hospital from 2015 to 2019. We analyzed the following covariates: age, sex, diabetes mellitus as cause of CKD, temporary central venous catheter (CVC) as initial vascular access and glomerular filtration rate. Survival was calculated with Kaplan-Meier curves for the overall cohort and for age ≥ 60 years, diabetes mellitus as a cause of CKD and CVC. The risk of death was estimated by Hazard Ratio (HR) according to the Cox proportional hazards model for each covariate adjusted for dialysis type in a bivariate and multivariate analysis considering significant difference if the p-value < 0.05. Results. We included 368 patients on HD of whom 129 (35.1%) died, and 172 patients on PD of whom 66 (38.4%) died (p=0.455). The cumulative probability of survival at 60 months for HD was 30% and for PD was 37% with similar survival curves (p=0.719). The median survival time for HD was 32 months (IQR: 20-53) and for PD was 32.5 months (IQR: 18-57) (p=0.999). The covariates associated with higher mortality adjusted for dialysis type were age ≥60 years (HR 1.77; p<0.001) and diabetes mellitus as a cause of CKD (HR 1.63; p=0.002). Conclusions. Survival of patients with CKD on HD and PD was similar. [ABSTRACT FROM AUTHOR]

Mediation analysis has been receiving much attention from the scientific community in the last years, mainly due to its ability to disentangle causal pathways from exposures to outcomes. Particularly, causal mediation analysis for time-to-event outcomes has been widely discussed using accelerated failures times, Cox and Aalen models, with continuous or binary mediator. We derive general expressions for the Natural Direct Effect and Natural Indirect Effect for the time-to-event outcome when the mediator is modeled using generalized linear models, which includes existing procedures as particular cases. We also define a responsiveness measure to assess the variations in continuous exposures in the presence of mediation. We consider a community-based prospective cohort study that investigates the mediation of hepatitis B in the relationship between hepatitis C and liver cancer. We fit different models as well as distinct distributions and link functions associated to the mediator. We also notice that estimation of NDE and NIE using different models leads to non-contradictory conclusions despite their effect scales. The survival models provide a compelling framework that is appropriate to answer many research questions involving causal mediation analysis. The extensions through GLMs for the mediator may encompass a broad field of medical research, allowing the often necessary control for confounding. [ABSTRACT FROM AUTHOR]

Objective. Estimate five-year survival from cervical cancer and associated factors in Mexican patients financed by Seguro Popular during the period 2006-2014. Materials and methods. We analyzed the database of patients financed by the Catastrophic Expenses Protection Fund and linked it to the Statistical and Epidemiological System of mortality. We performed a five-year survival analysis by clinical stage and associated factors, using the Kaplan-Meier method and Cox proportional hazards models. Results. Overall survival for cervical cancer at five years was 68.5%. The associated factors were the clinical stage: locoregional (HR=2.8 CI95% HR: 2.6,3.0) and metastatic (HR=5.4 CI95% HR: 4.9,5.9) compared to early stage and age (HR=1.003 CI95% HR:1.001,1.004). Conclusions. Women who gained access to Catastrophic Expenses Protection Fund cervical cancer care had similar survival than that reported in other studies. [ABSTRACT FROM AUTHOR]

Objective. To evaluate, using semiparametric methodologies of survival analysis, the relationship between covariates and time to death of patients with breast cancer, as well as the determination discriminatory power in the conditional inference tree of patients who had cancer. Methods. A retrospective cohort study was conducted using data collected from medical records of women who had breast cancer and underwent treatment between 2005 and 2015 at the Hospital da Fundação de Assistencial da Paraíba in Campina Grande, State of Paraiba, Brazil. Survival curves were estimated using the Kaplan--Meier method, Cox regression, and conditional decision tree. Results. Women with triple-negative molecular subtypes had a shorter survival time compared to women with positive hormone receptors. The addition of hormone therapy reduced the risk of a patient dying by 5.5%, and the risk of a HER2-positive patient dying was 34.5% lower compared to those who were negative for this gene. Patients undergoing hormone therapy had a median survival time of 4 753 days. Conclusions. This paper shows a favorable scenario for the use of immunotherapy for patients with HER2 overexpression. Further studies could assess the effectiveness of immunotherapy in patients with other conditions, to favor the prognosis and better quality of life for the patient. [ABSTRACT FROM AUTHOR]

Copyright of Revista Latinoamericana de Población is the property of Revista Latinoamericana de Poblacion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To build an evaluation predictive model of time between Human Immunodeficiency Virus diagnosis and first hospitalization. Methods: An epidemiological, descriptive, and retrospective study, with a sample of 200 medical records of people with Acquired Immunodeficiency Syndrome, monitored in a specialized service. Survival analysis was performed using the Kaplan-Meier estimator, the Weibull parametric model, and the Cox semi-parametric model. Results: There were significant differences in time between diagnosis and hospitalization regarding age, sexual orientation, therapy discontinuation records, and the number of medical and multidisciplinary consultations. The Weibull model presented the record of therapy discontinuity as a significant co-variable. In the Cox model, the occupation, alcohol and psychotropic use, T-CD4+ lymphocyte count, viral load, and psychiatric history variables were significant to explain the risk of hospitalization. Conclusion: It was possible to identify the risk and protection factors for the outcome hospitalization. The models also pointed out factors that influence the time between human immunodeficiency virus diagnosis and first hospitalization, and enabled an enriching discussion about the intrinsic aspects of health care for people living with the virus and the disease. [ABSTRACT FROM AUTHOR]

Copyright of Biomédica: Revista del Instituto Nacional de Salud is the property of Instituto Nacional de Salud of Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Prostate cancer is currently one of the main pathologies that affects men. The objective of this article was to estimate the survival of patients with intermediate and high risk prostate cancer belonging to the special health regimen. A cohort study was conducted that estimates the survival function with the Kaplan-Meier method, the Hazard ratio (HR) as a function of explanatory variables using a Cox regression model. The patients included were diagnosed by urology and / or confirmed with diagnostic support, patients treated for prostate cancer in another institution, primary tumors other than the prostate, and those who consulted for a second medical opinion were not included. Intermediate-risk patients survive 90% to both 5 and 7 years, and high-risk patients survive 35% and 30% to 5 and 7 years, respectively, with a median of 28 months. This study allowed us to conclude that survival in patients classified as intermediate risk is similar to national and international ones, however, in high-risk patients, survival is lower than in other countries. [ABSTRACT FROM AUTHOR]

Copyright of Cirugía y Cirujanos is the property of Publicidad Permanyer SLU and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Gaucha de Enfermagem is the property of Revista Gaucha de Enfermagem and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Being able to determine that an instrument predicts behavior such as violence or recidivism is one of the main objectives of legal psychology. Predictive validity, as it is known, allows evaluating this characteristic. This type of validity has been evaluated through various techniques, such as contingency tables, sensitivity, specificity, and ROC curves. However, these techniques do not address a major statistical problem: data censorship that occurs in prospective studies, since in many cases the subjects will not relapse during the follow-up performed. Survival analysis is a technique that allows taking this information into consideration and modeling the time until a certain event happens. Through different approaches, such as its descriptive techniques or Cox proportional hazards models, this technique allows us to evaluate the predictive power of tests, as well as of interventions. [ABSTRACT FROM AUTHOR]

Copyright of Economía, Sociedad y Territorio is the property of El Colegio Mexiquense and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Usually, the exact time at which an event occurs cannot be observed for several reasons; for instance, it is not possible to constantly monitor a characteristic of interest. This generates a phenomenon known as censoring that can be classified as having a left censor, right censor or interval censor. When one is working with survival data in the presence of arbitrary censoring, the survival time of interest is defined as the elapsed time between an initial event and the next event that is generally unknown. This problem has been widely studied in the statistic literature and some progress has been made, toward resolving and the formulation of a bivariate likelihood to estimate parameters in a parametric regression model offers positive development opportunities. In this paper, we construct a bivariate likelihood for the Weibull regression model in the presence of interval censoring. Finally, its performance is illustrated by means of a simulation study. [ABSTRACT FROM AUTHOR]

Copyright of Adicciones is the property of Sociedad Cientifica Espanola de Estudios sobre el Alcohol and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective. To identify disparities--using recursive partitioning (RP)--in early survival for children with leukemias treated in Argentina, and to depict the main characteristics of the most vulnerable groups. Methods. This secondary data analysis evaluated 12-month survival (12-ms) in 3 987 children diagnosed between 2000 and 2008 with lymphoid leukemia (LL) and myeloid leukemia (ML) and registered in Argentina's population-based oncopediatric registry. Prognostic groups based on age at diagnosis, gender, socioeconomic index of the province of residence, and migration to a different province to receive health care were identified using the RP method. Results. Overall 12-ms for LL and ML cases was 83.7% and 59.9% respectively. RP detected major gaps in 12-ms. Among 1-10-year-old LL patients from poorer provinces, 12-ms for those who did and did not migrate was 87.0% and 78.2% respectively. Survival of ML patients < 2 years old from provinces with a low/medium socioeconomic index was 38.9% compared to 62.1% for those in the same age group from richer provinces. For 2-14-year-old ML patients living in poor provinces, patient migration was associated with a 30% increase in 12-ms. Conclusions. Major disparities in leukemia survival among Argentine children were found. Patient migration and socioeconomic index of residence province were associated with survival. The RP method was instrumental in identifying and characterizing vulnerable groups. [ABSTRACT FROM AUTHOR]

Copyright of Biomédica: Revista del Instituto Nacional de Salud is the property of Instituto Nacional de Salud of Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Eletrônica de Enfermagem is the property of Revista Eletronica de Enfermagem and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Estudios Gerenciales is the property of Universidad ICESI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose To provide an example of censored data analysis in the management of CED-S missing data, using a data set of a study conducted with Mexican rural women. Material and Methods Data used for this exercise were collected in a cross-sectional study with 416 women in the Mexican region known as the Mixteca Baja. Using a Survival Analysis (SA) focus we present a general description of the scores, along with the estimation of association patterns between those scores and the independent variables departing from Cox's proportional risk model. A comparison is made of these results and those obtained through a regression analysis. Results Using only the information from observations with complete data, the average CES-D score was 11.0 and the prevalence of symptoms above the cut-off point (16) was 23.2%. Twenty-six percent of the women did not respond to at least one item. When conducting the SA, the estimated mean score of the scale was 14.0. Survival above the cut-off point corresponded to an estimated prevalence of 21%. Conclusions SA is useful in the management of data sets with missing data in scales such as the CES-D. In this example, the increased percentage of observations with missing data produced a loss of precision in the estimators. The differences in mean item scores between observation with complete and incomplete data suggested a non-random, noresponse pattern, if this is not taken into consideration it could bias the estimation in the scale mean and its association with other variables. Conducting SA we were able to use the information of most women participating in the study, including those who did not respond to all items in the scale. [ABSTRACT FROM AUTHOR]

Copyright of Revista Española de Cardiología (18855857) is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective To analyse the outcomes of antiretroviral therapy (ART) in routine conditions in a rural hospital in the Far-North province of Cameroon. Method Retrospective cohort study of 1187 patients >15 years who started ART between July 2001 and December 2006. The survival time was estimated by Kaplan–Meier analysis and Cox proportional hazard models were fitted to explain survival. Results Upon enrolment, 90.4% patients were in WHO stage III or IV and 56.1% had a BMI <18.5. Median CD4 count was 105 cells/mm³ (IQR 40–173). At the end of the study period, 338/1187 had died and 59/1187 were lost to follow-up. The survival probability was 77% at 1 year [95% CI: 75–80] and 47% at 5 years [95% CI: 40–55]. The median survival time was 58 months. CD4 count, haemoglobin, BMI, sex and clinical stage at enrolment were independent predictors of mortality. Conclusion This study confirms the clinical benefit of ART programs in a remote and resource-constrained setting operating in routine conditions. The challenge ahead is to secure earlier access to ART and to maintain its longer-term benefit. [ABSTRACT FROM AUTHOR]

This article presents a study analysing the relationships between a set of psychological variables and the time people spend in getting a job. Age and gender are also considered. An expectations-based model to explain motivated behaviour in finding a job is suggested. The Perceived Control Expectancies in Job Finding Scale (PCEJFS) is used as a cognitive variable. Survival Analysis (Cox regression) is used as statistical analysis. The results show a significant relationship between motivation and duration of unemployment. Comparing people with higher and lower scores in PCEJF scales, it takes people with higher scores an average of 14 months shorter to find a job than people with lower scores. Females and people over thirty spend longer in securing employment. [ABSTRACT FROM AUTHOR]

Although land changes are characterized by dimensionality in both space and time, and a multitude of methods and techniques have been developed to model them, the temporal dimension has seldom been adequately addressed by commonly used methods. In the context of temporal complexities represented in different space-time data models, this study aims to establish a framework for applying survival analysis theory and techniques to geographical land change modeling. Our efforts focus on (1) introducing basic concepts in survival analysis and their connections to space-time data commonly used in land change analysis, (2) using survival metrics to describe temporal patterns that are not easily detected by other methods, and (3) applying survival analysis methods to disclose effects of varying temporal patterns and uncertainties. Our findings suggest that survival analysis, coupled with geographic information systems (GIS) and remote sensing data, can effectively disclose relationships in land changes, and in many instances excel in shedding light on the temporal patterns of land changes. [ABSTRACT FROM AUTHOR]

The article presents an introduction to cohort studies in epidemiology, as well as an analysis of survival. Cohort designs has quickly become one of the most methodological tools utilized in epidemiological and medical investigations. Fundamental concepts of cohorts are analyzed. The focus of this article is the variable cohort designs as well as the basic tools that were used in creating them as a part of survival analysis. Finally, the paper focuses in on a cohort study relating the age at which smokers begin to smoke in relationship to schizophrenia.