ABSTRACT
There is a general belief that the quality of Twitter data streams is generally low and unpredictable, making, in some way, unreliable to take decisions based on such data. The work presented here addresses this problem from a Data Quality (DQ) perspective, adapting the traditional methods used in relational databases, based on quality dimensions and metrics, to capture the characteristics of Twitter data streams in particular, and of Big Data in a more general sense. Therefore, as a first contribution, this paper re-defines the classic DQ dimensions and metrics for the scenario under study. Second, the paper introduces a software tool that allows capturing Twitter data streams in real time, computing their DQ and displaying the results through a wide variety of graphics. As a third contribution of this paper, using the aforementioned machinery, a thorough analysis of the DQ of Twitter streams is performed, based on four dimensions: Readability, Completeness, Usefulness, and Trustworthiness. These dimensions are studied for several different cases, namely unfiltered data streams, data streams filtered using a collection of keywords, and classifying tweets referring to different topics, studying the DQ for each topic. Further, although it is well known that the number of geolocalized tweets is very low, the paper studies the DQ of tweets with respect to the place from where they are posted. Last but not least, the tool allows changing the weights of each quality dimension considered in the computation of the overall data quality of a tweet. This allows defining weights that fit different analysis contexts and/or different user profiles. Interestingly, this study reveals that the quality of Twitter streams is higher than what would have been expected.
ABSTRACT
The General Transit Feed Specification (GTFS) is a data format widely used to share data about public transportation schedules and associated geographic information. GTFS comes in two versions: GTFS Static describing the planned itineraries and GTFS Realtime describing the actual ones. MobilityDB is a novel and free open-source moving object database, developed as a PostgreSQL and PostGIS extension, that adds spatial and temporal data types along with a large number of functions, that facilitate the analysis of mobility data. Loading GTFS data into MobilityDB is a quite complex task that, nevertheless, must be done in an ad-hoc fashion. This work describes how MobilityDB is used to analyze public transport mobility in the city of Buenos Aires, using both, static and real-time GTFS data for the Buenos Aires public transportation system. Visualizations are also produced to enhance the analysis. To the authors' knowledge, this is the first attempt to analyze GTFS data with a moving object database.
ABSTRACT
OBJETIVO: Encuestar a cirujanos de rodilla en Chile, sobre su conducta en contaminaciones accidentales del injerto, en reconstrucciones de ligamento cruzado anterior (LCA). MÉTODOS: Se realizó una encuesta anónima en relación a la incidencia, tratamiento y resultados clínicos de los injertos de LCA contaminados, a todos los médicos pertenecientes al área de traumatología y ortopedia asistentes al congreso Ateneo de rodilla 2015. RESULTADOS: Se encuestaron 54 médicos, 33 (61%) especialistas en cirugía de rodilla y 21 (39%) médicos en formación. De los cirujanos de rodilla, 15 (45%) reportaron al menos un caso de contaminación, de los cuales 12 (80%) informaron un único evento, 3 (20%) indicaron la eventualidad en 2, 3 y 5 ocasiones respectivamente, para un total de 22 injertos contaminados. De los cirujanos que reportaron injertos contaminados, 11 (73%) realizan 50 o más reconstrucciones al año. La decisión tomada en los casos de contaminación fue en 13 oportunidades (59%), lavar el injerto y utilizarlo de acuerdo al plan inicial; en 6 casos (27%), utilizar aloinjerto; en 2 ocasiones (9%), utilizar autoinjerto alternativo; y en 1 oportunidad (5%); triplicar el semitendinoso. Ninguno de los casos de contaminación reportó infecciones. CONCLUSIONES: En casos de una contaminación accidental, la mayoría de los cirujanos encuestados prefieren optar por la descontaminación del injerto y su utilización en la reconstrucción de acuerdo al plan inicial; para lo cual la clorhexidina y antibióticos sería la solución a usar de preferencia. NIVEL DE EVIDENCIA: Nivel V, opinión de experto.
OBJECTIVE: To survey knee surgeons who perform anterior cruciate ligament (ACL) reconstruction in Chile, about the management when ACL graft contamination occurs. METHODS: An anonymous survey was conducted to all physicians belonging to the area of traumatology and orthopedics who attended the 2015 annual Chilean Knee Society meeting. The survey questioned the incidence, treatment, and outcomes of ACL graft contaminations. RESULTS: Fifty-four physicians were surveyed, of which 33 (61%) where knee surgeons and 21 (39%) physicians in training. Of the 33 knee surgeons, 15 (45%) reported at least one contamination during their career. Of those 15, 12 (80%) had one event, and three surgeons (20%) informed having 2, 3, and 5 episodes respectively, for a total of 22 reported contaminated grafts. Of the surgeons who reported a contaminated graft, 11 (73%) performed 50 or more ACL reconstructions annually. In 13 opportunities (59%) the management for a contaminated graft was cleansing the graft and proceeding as planned. In 6 cases (27%) an allograft was used, in 2 occasions (9%) a different graft was harvested, and in 1 opportunity (5%) a semitendinosus graft triplication was performed. No infections in any of the contaminated grafts were reported. CONCLUSIONS: In case of accidental graft contamination during an ACL reconstruction, knee surgeons most often preferred disinfecting the graft and using it as the initial plan. LEVEL OF EVIDENCE: Level V, expert opinion.
Subject(s)
Humans , Accidents , Equipment Contamination/statistics & numerical data , Transplants/microbiology , Anterior Cruciate Ligament Reconstruction/methods , Orthopedic Surgeons/psychology , Chlorhexidine/administration & dosage , Sterilization/methods , Decontamination , Equipment Contamination/prevention & control , Surveys and Questionnaires , Disinfectants/administration & dosage , Allografts/microbiology , Autografts/microbiology , Anti-Bacterial AgentsABSTRACT
The anterior cruciate ligament is the most commonly injured ligament, with up to 10% of surgery failure. Atraumatic instability in the early postoperative period (<6 months) occurs as the result of poor surgical technique, failure of graft integration, or early mechanical overload during rehabilitation. Engineered cell therapy is a developing resource designed to increase the rate of tendon-to-bone interface healing. We describe a simple and safe technique to harvest mesenchymal stem cells by arthroscopic bone marrow aspiration from the intercondylar notch.
ABSTRACT
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