Mining frequent bug-fix code changes

Detecting bugs as early as possible plays an important role in ensuring software quality before shipping. We argue that mining previous bug fixes can produce good knowledge about why bugs happen and how they are fixed. In this paper, we mine the change history of 717 open source projects to extract bug-fix patterns. We also manually inspect many of the bugs we found to get insights into the contexts and reasons behind those bugs. For instance, we found out that missing null checks and missing initializations are very recurrent and we believe that they can be automatically detected and fixed.

GOCE: precise orbit determination for the entire mission

The Gravity field and steady-state Ocean Circulation Explorer (GOCE) was the first Earth explorer core mission of the European Space Agency. It was launched on March 17, 2009 into a Sun-synchronous dusk-dawn orbit and re-entered into the Earth’s atmosphere on November 11, 2013. The satellite altitude was between 255 and 225 km for the measurement phases. The European GOCE Gravity consortium is responsible for the Level 1b to Level 2 data processing in the frame of the GOCE High-level processing facility (HPF). The Precise Science Orbit (PSO) is one Level 2 product, which was produced under the responsibility of the Astronomical Institute of the University of Bern within the HPF. This PSO product has been continuously delivered during the entire mission. Regular checks guaranteed a high consistency and quality of the orbits. A correlation between solar activity, GPS data availability and quality of the orbits was found. The accuracy of the kinematic orbit primarily suffers from this. Improvements in modeling the range corrections at the retro-reflector array for the SLR measurements were made and implemented in the independent SLR validation for the GOCE PSO products. The satellite laser ranging (SLR) validation finally states an orbit accuracy of 2.42 cm for the kinematic and 1.84 cm for the reduced-dynamic orbits over the entire mission. The common-mode accelerations from the GOCE gradiometer were not used for the official PSO product, but in addition to the operational HPF work a study was performed to investigate to which extent common-mode accelerations improve the reduced-dynamic orbit determination results. The accelerometer data may be used to derive realistic constraints for the empirical accelerations estimated for the reduced-dynamic orbit determination, which already improves the orbit quality. On top of that the accelerometer data may further improve the orbit quality if realistic constraints and state-of-the-art background models such as gravity field and ocean tide models are used for the reduced-dynamic orbit determination.

Firearm legislation and firearm mortality in the USA: a cross-sectional, state-level study.

BACKGROUND In an effort to reduce firearm mortality rates in the USA, US states have enacted a range of firearm laws to either strengthen or deregulate the existing main federal gun control law, the Brady Law. We set out to determine the independent association of different firearm laws with overall firearm mortality, homicide firearm mortality, and suicide firearm mortality across all US states. We also projected the potential reduction of firearm mortality if the three most strongly associated firearm laws were enacted at the federal level. METHODS We constructed a cross-sectional, state-level dataset from Nov 1, 2014, to May 15, 2015, using counts of firearm-related deaths in each US state for the years 2008-10 (stratified by intent [homicide and suicide]) from the US Centers for Disease Control and Prevention's Web-based Injury Statistics Query and Reporting System, data about 25 firearm state laws implemented in 2009, and state-specific characteristics such as firearm ownership for 2013, firearm export rates, and non-firearm homicide rates for 2009, and unemployment rates for 2010. Our primary outcome measure was overall firearm-related mortality per 100 000 people in the USA in 2010. We used Poisson regression with robust variances to derive incidence rate ratios (IRRs) and 95% CIs. FINDINGS 31 672 firearm-related deaths occurred in 2010 in the USA (10·1 per 100 000 people; mean state-specific count 631·5 [SD 629·1]). Of 25 firearm laws, nine were associated with reduced firearm mortality, nine were associated with increased firearm mortality, and seven had an inconclusive association. After adjustment for relevant covariates, the three state laws most strongly associated with reduced overall firearm mortality were universal background checks for firearm purchase (multivariable IRR 0·39 [95% CI 0·23-0·67]; p=0·001), ammunition background checks (0·18 [0·09-0·36]; p<0·0001), and identification requirement for firearms (0·16 [0·09-0·29]; p<0·0001). Projected federal-level implementation of universal background checks for firearm purchase could reduce national firearm mortality from 10·35 to 4·46 deaths per 100 000 people, background checks for ammunition purchase could reduce it to 1·99 per 100 000, and firearm identification to 1·81 per 100 000. INTERPRETATION Very few of the existing state-specific firearm laws are associated with reduced firearm mortality, and this evidence underscores the importance of focusing on relevant and effective firearms legislation. Implementation of universal background checks for the purchase of firearms or ammunition, and firearm identification nationally could substantially reduce firearm mortality in the USA. FUNDING None.

The Church Music Program: The Effect of Moving from Performance-based to Education-based Emphasis in a Church Music Program

This research project sought to answer the primary research question: What occurs when the music program in a church changes its emphasis from performance to education? This qualitative study of a church choir included participant observation of Wednesday evening and Sunday morning rehearsals over a 12 week period, individual interviews, group interviews, written responses, and written and visual assessment of musical skills. The goal was a rich description of the participants and emerging themes resulting from the shift in emphasis. Analysis of data occurred through inductive processing. Data was initially coded and then the codes were categorized into sub-themes, and finally into major themes. Early analysis of the data began with reflection in a researcher journal. Following the completion of the study the journal was entered into a word processor, as were transcriptions of videotaped rehearsals, and written reflections from the participants. After all data had been reviewed repeatedly and entered into the word processor, it was coded, reexamined, and finally categorized into sub-themes and themes. After coding and identification of major themes and sub-themes the finding were challenged by looking for disconfirming evidence. Finally, after the completion of the analysis stage, member checks were conducted. The results of the analysis of data revealed themes that could be associated either with the choir or the director. The key themes primarily associated with the choir were: Response to the change in rehearsal format; Attitude toward learning; Appropriateness of community learning model; and, Member's perceptions of the results of the program. The key themes associated with the director were identified as: Conductor assuming the role of educator; Conductor recognizing the choir as learners; Conductor treating rehearsals as a time for teaching and learning; and, Conductor's perception of the effectiveness of the change in focus. The study concluded that a change in focus from performance to education did not noticeably improve the sound of the choir after twelve-weeks. There were however, indications that improvements were being made by the individual members. Further study of the effects over a longer period of time is recommended.

Descriptive epidemiology of cancer in three regions of Kazakhstan

The current study investigated data quality and estimated cancer incidence and mortality rates using data provided by Pavlodar, Semipalatinsk and Ust-Kamenogorsk Regional Cancer Registries of Kazakhstan during the period of 1996–1998. Assessment of data quality was performed using standard quality indicators including internal database checks, proportion of cases verified from death certificates only, mortality:incidence ratio, data patterns, proportion of cases with unknown primary site, proportion of cases with unknown age. Crude and age-adjusted incidence and mortality rates and 95% confidence intervals were calculated, by gender, for all cancers combined and for 28 specific cancer sites for each year of the study period. The five most frequent cancers were identified and described for every population. The results of the study provide the first simultaneous assessment of data quality and standardized incidence and mortality rates for Kazakh cancer registries. ^

Identifying Individual and Group Effects in the Presence of Sorting: A Neighborhood Effects Application

Researchers have long recognized that the non-random sorting of individuals into groups generates correlation between individual and group attributes that is likely to bias naive estimates of both individual and group effects. This paper proposes a non-parametric strategy for identifying these effects in a model that allows for both individual and group unobservables, applying this strategy to the estimation of neighborhood effects on labor market outcomes. The first part of this strategy is guided by a robust feature of the equilibrium in the canonical vertical sorting model of Epple and Platt (1998), that there is a monotonic relationship between neighborhood housing prices and neighborhood quality. This implies that under certain conditions a non- parametric function of neighborhood housing prices serves as a suitable control function for the neighborhood unobservable in the labor market outcome regression. The second part of the proposed strategy uses aggregation to develop suitable instruments for both exogenous and endogenous group attributes. Instrumenting for each individual's observed neighborhood attributes with the average neighborhood attributes of a set of observationally identical individuals eliminates the portion of the variation in neighborhood attributes due to sorting on unobserved individual attributes. The neighborhood effects application is based on confidential microdata from the 1990 Decennial Census for the Boston MSA. The results imply that the direct effects of geographic proximity to jobs, neighborhood poverty rates, and average neighborhood education are substantially larger than the conditional correlations identified using OLS, although the net effect of neighborhood quality on labor market outcomes remains small. These findings are robust across a wide variety of specifications and robustness checks.

The feasibility of self-report advance directives among elderly patients with cognitive impairment

The central objective of this dissertation was to determine the feasibility of self-completed advance directives (AD) in older persons suffering from mild and moderate stages of dementia. This was accomplished by identifying differences in ability to complete AD among elderly subjects with increasing degrees of dementia and cognitive incompetence. Secondary objectives were to describe and compare advance directives completed by elders and identified proxy decision makers. Secondary objectives were accomplished by measuring the agreement between advance directives completed by proxy and elder, and comparing that agreement across groups defined by the elder's cognitive status. This cross-sectional study employed a structured interview to elicit AD, followed by a similar interview with a proxy decision maker identified by the elder. A stratified sampling scheme recruited elders with normal cognition, mild, and moderate forms of dementia using the Mini Mental-State Exam (MMSE). The Hopkins Competency Assessment Test (HCAT) was used for evaluation of competency to make medical decisions. Analysis was conducted on "between group" (non-demented $\leftrightarrow$ mild dementia $\leftrightarrow$ moderate dementia, and competent $\leftrightarrow$ incompetent) and "within group" (elder $\leftrightarrow$ family member) variation.^ The 118 elderly subjects interviewed were generally male, Caucasian, and of low socioeconomic status. Mean age was 77. Overall, elders preferred a "trial of therapy" regarding AD rather than to "always receive the therapy". No intervention was refused outright more often than it was accepted. A test-retest of elders' AD revealed stable responses. Eleven logic checks measured appropriateness of AD responses independent of preference. No difference was found in logic error rates between elders grouped by MMSE or HCAT. Agreement between proxy and elder responses showed significant dissimilarity, indicating that proxies were not making the same medical decisions as the elders.^ Conclusions based on these data are: (1) Self reporting AD is feasible among elders showing signs of cognitive impairment and they should be given all opportunities to complete advance directives, (2) variation in preferences for advance directives in cognitively impaired elders should not be assumed to be the effects of their impairment alone, (3) proxies do not appear to forego life-prolonging interventions in the face of increasing impairment in their ward, however, their advance directives choices are frequently not those of the elder they represent. ^

Data Accuracy in Medical Record Abstraction

Clinical Research Data Quality Literature Review and Pooled Analysis We present a literature review and secondary analysis of data accuracy in clinical research and related secondary data uses. A total of 93 papers meeting our inclusion criteria were categorized according to the data processing methods. Quantitative data accuracy information was abstracted from the articles and pooled. Our analysis demonstrates that the accuracy associated with data processing methods varies widely, with error rates ranging from 2 errors per 10,000 files to 5019 errors per 10,000 fields. Medical record abstraction was associated with the highest error rates (70–5019 errors per 10,000 fields). Data entered and processed at healthcare facilities had comparable error rates to data processed at central data processing centers. Error rates for data processed with single entry in the presence of on-screen checks were comparable to double entered data. While data processing and cleaning methods may explain a significant amount of the variability in data accuracy, additional factors not resolvable here likely exist. Defining Data Quality for Clinical Research: A Concept Analysis Despite notable previous attempts by experts to define data quality, the concept remains ambiguous and subject to the vagaries of natural language. This current lack of clarity continues to hamper research related to data quality issues. We present a formal concept analysis of data quality, which builds on and synthesizes previously published work. We further posit that discipline-level specificity may be required to achieve the desired definitional clarity. To this end, we combine work from the clinical research domain with findings from the general data quality literature to produce a discipline-specific definition and operationalization for data quality in clinical research. While the results are helpful to clinical research, the methodology of concept analysis may be useful in other fields to clarify data quality attributes and to achieve operational definitions. Medical Record Abstractor’s Perceptions of Factors Impacting the Accuracy of Abstracted Data Medical record abstraction (MRA) is known to be a significant source of data errors in secondary data uses. Factors impacting the accuracy of abstracted data are not reported consistently in the literature. Two Delphi processes were conducted with experienced medical record abstractors to assess abstractor’s perceptions about the factors. The Delphi process identified 9 factors that were not found in the literature, and differed with the literature by 5 factors in the top 25%. The Delphi results refuted seven factors reported in the literature as impacting the quality of abstracted data. The results provide insight into and indicate content validity of a significant number of the factors reported in the literature. Further, the results indicate general consistency between the perceptions of clinical research medical record abstractors and registry and quality improvement abstractors. Distributed Cognition Artifacts on Clinical Research Data Collection Forms Medical record abstraction, a primary mode of data collection in secondary data use, is associated with high error rates. Distributed cognition in medical record abstraction has not been studied as a possible explanation for abstraction errors. We employed the theory of distributed representation and representational analysis to systematically evaluate cognitive demands in medical record abstraction and the extent of external cognitive support employed in a sample of clinical research data collection forms. We show that the cognitive load required for abstraction in 61% of the sampled data elements was high, exceedingly so in 9%. Further, the data collection forms did not support external cognition for the most complex data elements. High working memory demands are a possible explanation for the association of data errors with data elements requiring abstractor interpretation, comparison, mapping or calculation. The representational analysis used here can be used to identify data elements with high cognitive demands.

La función regulatoria del Estado (regulación y prestación de servicios públicos)

El proceso de reforma del Estado experimentado en la Argentina en la década de los 90, significó tanto para las instituciones como para los ciudadanos un cambio profundo en las relaciones que hasta el momento se habían dado entre sociedad y Estado. Los principales instrumentos de este proceso: la desregulación económica, la privatización de servicios y la descentralización de funciones, significaron en su conjunto un cambio sustancial en el papel regulador del Estado, quien deja de ser el prestador, y el corrector de las fallas del mercado, para constituirse ( real o potencialmente) en el garante de su cabal funcionamiento .Sin embargo en el caso de la transferencia de los servicios públicos al sector privado en la Argentina, al haber sido el Estado, el anterior prestador monopólico de los mismos, dejó un vacío que requirió del mismo no ya desregulación sino un nuevo papel regulador, respecto de los prestadores y los usuarios de dichos servicios. En este trabajo se efectúa una descripción de los enfoques económicos y jurídicos desde los cuales se plantea la función regulatoria del Estado a partir del conjunto de leyes, decretos, resoluciones y reglamentaciones del gobierno nacional que significaron cambios importantes en el papel asignado al Estado por el Gobierno en ejercicio durante la última década.

La gestión urbano-regional en un escenario globalizado : nuevos retos para su enseñanza

Se revisa la situación y el papel de los programas de formación de recursos humanos para la gestión del desarrollo urbano y regional de América Latina, a la luz de las transformaciones ocasionadas en las últimas décadas por los avances de la reestructuración productiva y la globalización. Con tal propósito considera su impacto sobre las condiciones que encuadran a este tipo de gestión, tratando de identificar sus principales efectos en la orientación, el contenido y la efectividad de dichos programas. En esa dirección analiza las implicancias de dichas transformaciones, tanto sobre el propio escenario de la acción social, como sobre las explicaciones teóricas sobre la generación del crecimiento económico, tratando de mostrar como ello altera las coordenadas básicas tanto de la gestión, como de los respectivos programas de formación urbano-regionales.

Prevención de complicaciones orales en personas con discapacidad severa

La salud, como derecho primordial de toda persona, adquiere una connotación especial cuando la persona tiene una discapacidad. El término Discapacidad describe una restricción o ausencia, debido a una deficiencia, de la capacidad de realizar una actividad en la forma o dentro del margen que se considera normal para el ser humano. Si nos referimos concretamente a la salud bucal, podemos decir, que presentan alta incidencia de patologías por lo que constituyen un grupo de riesgo con una gran necesidad de cuidados dentales. Es importante destacar que gran parte de las personas con Discapacidad, no pueden expresar en palabras o determinar claramente su proceso patológico y así toleran importantes dolores demostrados mediante el aumento de la irritabilidad, la inactividad, la pérdida de apetito, los problemas de sueño, la autoagresión, etc. Esta falta de certeza y reacciones adversas genera una situación familiar de alteración de la vida cotidiana y desconcierto, además de comenzar a realizar una serie de consultas a psiquiatra, otorrinolaringólogo, neurólogo, clínico, entre otros especialistas. Dicha situación puede ser previsible mediante controles odontológicos periódicos, derivación temprana a exámenes bucales por parte de médicos y/u otros especialistas tratantes, interconsulta con odontólogo ante cambios de conducta o autoagresión. La prevención y el cuidado de la salud dental en los pacientes con discapacidad favorecen el mantenimiento de la salud general y proporcionan una mayor calidad de vida. La intervención del odontólogo en patologías ya instaladas consiste en la eliminación de la sintomatología, detención y tratamiento de las lesiones, restauración de la función y la estética.

Calibration of tracer concentration measurement and results

A reliable assessment of relevant substance flows is very important for environmental risk assessments and efficiency analysis of measures to reduce or avoid emissions of micropollutants like drugs to water systems. Accordingly, a detailed preparation of monitoring campaigns should include an accuracy check for the sampling configuration to prove the reliability of the monitoring results and the subsequent data processing. The accuracy of substance flow analyses is expected to be particularly weak for substances having high short-term variations of concentrations in sewage. This is especially the case linked to the observation of substance flows close to source in waste water systems. The verification of a monitoring configuration in a hospital sewer in Luxembourg is in the centre of interest of the case study presented here. A tracer test in the sewer system under observation is an essential element of the suggested accuracy check and provides valuable information for an uncertainty analysis. The results illustrate the importance of accuracy checks as an essential element of the preparation of monitoring campaigns. Moreover the study shows that continuous flow proportional sampling enables a representative observation of short-term peak loads of the iodinated x-ray contrast media iobitridol close to source.

El mundo del trabajo vitivinícola en Mendoza (Argentina) durante la modernización capitalista, 1880-1914

Este artículo traza un breve panorama del proceso de desarrollo de la vitivinicultura capitalista en Mendoza y luego, utilizando diversas fuentes primarias y secundarias, determina la composición del mercado de trabajo vitivinícola y su evolución cuantitativa y cualitativa. La introducción de equipamiento técnico de avanzada obligó a la capacitación de la mano de obra con mejoras en los ingresos de los asalariados. Este mercado se complejizó con el tiempo y aparecieron múltiples jerarquías, desde el peón al enólogo o director técnico de las bodegas, pasando por los contratistas de viñas o los capataces. Muchos trabajadores ascendieron socialmente y se convirtieron en empresarios, en itinerarios que respondieron a diversas estrategias rastreables en las fuentes. Finalmente, las condiciones laborales que tuvieron los trabajadores muestran la precariedad en la que se desenvolvían y la indefensión en la que estaban inmersos por la ausencia de colectivos gremiales que asumieran la representación del trabajo frente al capital.

IBAMar DATABASE: 4 decades of oceanographic sampling on the Western Mediterranean Sea

IBAMar (http://www.ba.ieo.es/ibamar) is a regional database that puts together all physical and biochemical data obtained by multiparametric probes (CTDs equipped with different sensors), during the cruises managed by the Balearic Center of the Spanish Institute of Oceanography (COB-IEO). It has been recently extended to include data obtained with classical hydro casts using oceanographic Niskin or Nansen bottles. The result is a database that includes a main core of hydrographic data: temperature (T), salinity (S), dissolved oxygen (DO), fluorescence and turbidity; complemented by bio-chemical data: dissolved inorganic nutrients (phosphate, nitrate, nitrite and silicate) and chlorophyll-a. In IBAMar Database, different technologies and methodologies were used by different teams along the four decades of data sampling in the COB-IEO. Despite of this fact, data have been reprocessed using the same protocols, and a standard QC has been applied to each variable. Therefore it provides a regional database of homogeneous, good quality data. Data acquisition and quality control (QC): 94% of the data are CTDs Sbe911 and Sbe25. S and DO were calibrated on board using water samples, whenever a Rossetta was available (70% of the cases). All CTD data from Seabird CTDs were reviewed and post processed with the software provided by Sea-Bird Electronics. Data were averaged to get 1 dbar vertical resolution. General sampling methodology and pre processing are described in https://ibamardatabase.wordpress.com/home/). Manual QC include visual checks of metadata, duplicate data and outliers. Automatic QC include range check of variables by area (north of Balearic Islands, south of BI and Alboran Sea) and depth (27 standard levels), check for spikes and check for density inversions. Nutrients QC includes a preliminary control and a range check on the observed level of the data to detect outliers around objectively analyzed data fields. A quality flag is assigned as an integer number, depending on the result of the QC check.

El mundo del trabajo vitivinícola en Mendoza (Argentina) durante la modernización capitalista, 1880-1914

Este artículo traza un breve panorama del proceso de desarrollo de la vitivinicultura capitalista en Mendoza y luego, utilizando diversas fuentes primarias y secundarias, determina la composición del mercado de trabajo vitivinícola y su evolución cuantitativa y cualitativa. La introducción de equipamiento técnico de avanzada obligó a la capacitación de la mano de obra con mejoras en los ingresos de los asalariados. Este mercado se complejizó con el tiempo y aparecieron múltiples jerarquías, desde el peón al enólogo o director técnico de las bodegas, pasando por los contratistas de viñas o los capataces. Muchos trabajadores ascendieron socialmente y se convirtieron en empresarios, en itinerarios que respondieron a diversas estrategias rastreables en las fuentes. Finalmente, las condiciones laborales que tuvieron los trabajadores muestran la precariedad en la que se desenvolvían y la indefensión en la que estaban inmersos por la ausencia de colectivos gremiales que asumieran la representación del trabajo frente al capital.