Large magnetoresistance using hybrid spin filter devices

A magnetic "spin filter" tunnel barrier, sandwiched between a non-magnetic metal and a magnetic metal, is used to create a new magnetoresistive tunnel device, somewhat analogous to an optical polarizer-analyzer configuration. The resistance of these trilayer structures depends on the relative magnetization orientation of the spin filter and the ferromagnetic electrode. The spin filtering in this configuration yields a previously unobserved magnetoresistance effect, exceeding 100%.Comment: 3.5 pages, 3 figures, submitted to Appl. Phys. Let

Data Validation Infrastructure for R

Checking data quality against domain knowledge is a common activity that pervades statistical analysis from raw data to output. The R package validate facilitates this task by capturing and applying expert knowledge in the form of validation rules: logical restrictions on variables, records, or data sets that should be satisfied before they are considered valid input for further analysis. In the validate package, validation rules are objects of computation that can be manipulated, investigated, and confronted with data or versions of a data set. The results of a confrontation are then available for further investigation, summarization or visualization. Validation rules can also be endowed with metadata and documentation and they may be stored or retrieved from external sources such as text files or tabular formats. This data validation infrastructure thus allows for systematic, user-defined definition of data quality requirements that can be reused for various versions of a data set or by data correction algorithms that are parameterized by validation rules

Empirical foundations for the diagnosis of somatization:implications for DSM-5

Background. The aim of this study was to develop empirically validated criteria for the diagnoses of clinically relevant somatization. Method. This study was performed in a population-representative cohort consisting of 461 males (47.8%) and 503 females (52.2%), with an average age of 55.8 years (S.D. = 11.1). Somatization, anxiety and depression were derived from the Composite International Diagnostic Interview. Mplus was used to perform confirmative factor analyses on the current DSM-IV symptom groups; on alternative symptom clusters previously suggested; and to perform latent class analysis in order to define an empirically derived cut-off for somatization. Results. The existence of symptom groups as described in DSM-IV was not supported by our data, whereas a differentiation between cardiopulmonary, musculoskeletal, gastrointestinal and general somatic symptoms did fit our data. Latent class analysis revealed two classes characterized by few (n = 859) and many (n = 105) symptoms. The class of subjects could be approached by a simple cut-off of four functional symptoms (sensitivity 79%, specificity 98%, positive predictive value 82%, negative predictive value 97%) regardless of the number of organ systems involved. Conclusions. This study in a large population-representative cohort suggests that a simple symptom count can be used as a dimensional diagnosis of somatization. In those instances in which a categorical diagnosis is preferred, a simple cut-off of four out of 43 functional symptoms best fitted our data. We did not find any added value for incorporating the number of symptom clusters into the diagnostic criteria