Long-term activity recognition from wristwatch accelerometer data.

With the development of wearable devices that have several embedded sensors, it is possible to collect data that can be analyzed in order to understand the user's needs and provide personalized services. Examples of these types of devices are smartphones, fitness-bracelets, smartwatches, just to mention a few. In the last years, several works have used these devices to recognize simple activities like running, walking, sleeping, and other physical activities. There has also been research on recognizing complex activities like cooking, sporting, and taking medication, but these generally require the installation of external sensors that may become obtrusive to the user. In this work we used acceleration data from a wristwatch in order to identify long-term activities. We compare the use of Hidden Markov Models and Conditional Random Fields for the segmentation task. We also added prior knowledge into the models regarding the duration of the activities by coding them as constraints and sequence patterns were added in the form of feature functions. We also performed subclassing in order to deal with the problem of intra-class fragmentation, which arises when the same label is applied to activities that are conceptually the same but very different from the acceleration point of view.

Novel genotypes in Helicobacter pylori involving domain V of the 23S rRNA gene.

BACKGROUND: Helicobacter pylori is a pathogenic bacterium that infects a half of the human population. In Chile, between 55% and 79% of people are colonized by H. pylori. At present, therapeutic strategies to eradicate the bacterium depend on the knowledge of its resistance to antibiotics. The clarithromycin resistance in H. pylori is associated with point mutations in the 23S rRNA. This study analyzes 23S rRNA gene mutations and minimum inhibitory concentration (MIC) for clarithromycin in H. pylori isolates from patients of the metropolitan region of Chile. MATERIALS AND METHODS: H. pylori isolates from 50 dyspeptic patients with no history of clarithromycin exposure were tested for clarithromycin resistance by agar dilution method. Resistant strains were analyzed for mutations in the 23S rRNA gene by polymerase chain reaction-based restriction fragment length polymorphism and sequencing. RESULTS: Primary resistance was observed in 10 isolates (20%). A single mutation was detected in four of the 10 isolates and two or more mutations in the other six cases. The C2147G transversion and G1939A, T1942C, and A2142G transitions in the peptidyltransferase region of domain V were novel. CONCLUSIONS: The study shows: 1, novel variants of the H. pylori 23S rRNA gene; and 2, a high prevalence of H. pylori displaying primary clarithromycin resistance with low level of MIC in an urban area of the Metropolitan Region of Chile.

[Prevalence of metronidazole, clarithromycin and tetracycline resistance in Helicobacter pylori isolated from Chilean patients]. / Prevalencia de la resistencia a metrodinazol, claritromicina y tetraciclina en Helicobacter pylori aislado de pacientes de la Región Metropolitana.

BACKGROUND: Helicobacter pylori is a pathogenic bacterium that infects a significant number of individuals. At present, therapeutic strategies to eradicate this bacterium depend on our knowledge of its resistance to antimicrobials. AIMS: To evaluate the primary resistance of H pylori to metronidazole (Mtz), clarithromycin (Cla), and tetracycline (Tet) in symptomatic out-patients. MATERIAL AND METHODS: Fifty independent isolates of H pylori were obtained by endoscopy-assisted gastric biopsy from patients attending the University of Chile Clinical Hospital, that previously had not been treated with an eradication regime against this bacterium. The minimal inhibitory concentration of each antimicrobial was determined by agar dilution method. RESULTS: Forty five and 27% of the isolates were found to be resistant to Mtz and Tet, respectively; the majority of these resistant isolates were from patients older than 21 years. Twenty percent of isolates were resistant to Cla; these were distributed evenly among different ages. Thirty two percent of the isolates were resistant to two or more of the antimicrobials. CONCLUSIONS: The high frequency of naturally occurring, antimicrobial-resistant strains of H pylori poses a national and world-wide problem for public health.