That secondary ulceration of the intestines is an insidious complication found at a comparatively early stage in a high percentage of cases of pulmonary tuberculosis, and that the detection of occult blood by means of the benzidine test in the faeces of such cases, is a useful and necessary method of diagnosis of the condition

Having carried out and reviewed the results of these investigations the writer is of opinion, (1) that secondary ulceration of the intestines is present in approximately half of all diagnosed cases of pulmonary tuberculosis - a proportion which increase to 80 90% before death. (2) that it is not essentially a terminal condition, but usually appears when the pulmonary lesion has advanced to a moderate extent. (3) that within one year from the first appearance of symptoms of pulmonary tuberculosis, secondary tuberculous intestinal ulceration has occurred in approximately half of the cases. (4) that it does not show its presence by means of symptoms until it has become extensive, and may indeed be found at autopsy in an advanced degree when there were no symptoms indicative of it during life. The investigator has also drawn the following minor conclusions,- (5) that, when the necessary precautions have been taken, and in the absence of other ulceration of the alimentary tract, a positive result obtained from the application of the benzidine test to the faeces of a patient suffering from pulmonary tuberculosis, is diagnostic of tuberculous ulceration of the intestine. (6) that it is possible to diagnose intestinal ulceration by means of the benzidine test,in a greater number of cases than by means of symptoms and clinical examination,or by radiological methods. (7) that it is impossible}by means of radiological methods at present available,to diagnose tuberculous intestinal ulceration where the small intestine alone is affected, but that the presence of occult blood in the faeces of such cases together with negative radiological findings in the large intestine is, in the absence of symptoms, the only method of diagnosis of such a condition

Opposing and following responses in sensorimotor speech control : why responses go both ways

When talking, speakers continuously monitor and use the auditory feedback of their own voice to control and inform speech production processes. When speakers are provided with auditory feedback that is perturbed in real time, most of them compensate for this by opposing the feedback perturbation. But some speakers follow the perturbation. In the current study, we investigated whether the state of the speech production system at perturbation onset may determine what type of response (opposing or following) is given. The results suggest that whether a perturbation-related response is opposing or following depends on ongoing fluctuations of the production system: It initially responds by doing the opposite of what it was doing. This effect and the non-trivial proportion of following responses suggest that current production models are inadequate: They need to account for why responses to unexpected sensory feedback depend on the production-system’s state at the time of perturbation

Leveraging covariate adjustments at scale in online A/B testing

Companies offering web services routinely run randomized online experiments to estimate the causal impact associated with the adoption of new features and policies on key performance metrics of interest. These experiments are used to estimate a variety of effects: the increase in click rate due to the repositioning of a banner, the impact on subscription rate as a consequence of a discount or special offer, etc. In these settings, even effects whose sizes are very small can have large downstream impacts. The simple difference in means estimator (Splawa-Neyman et al., 1990) is still the standard estimator of choice for many online A/B testing platforms due to its simplicity. This method, however, can fail to detect small effects, even when the experiment contains thousands or millions of observational units. As a by-product of these experiments, however, large amounts of additional data (covariates) are collected. In this paper, we discuss benefits, costs and risks of allowing experimenters to leverage more complicated estimators that make use of covariates when estimating causal effects of interest. We adapt a recently proposed general-purpose algorithm for the estimation of causal effects with covariates to the setting of online A/B tests. Through this paradigm, we implement several covariate-adjusted causal estimators. We thoroughly evaluate their performance at scale, highlighting benefits and shortcomings of different methods. We show on real experiments how "covariate-adjusted" estimators can (i) lead to more precise quantification of the causal effects of interest and (ii) fix issues related to imbalance across treatment arms - a practical concern often overlooked in the literature. In turn, (iii) these more precise estimates can reduce experimentation time, cutting cost and helping to streamline decision-making processes, allowing for faster adoption of beneficial interventions

Effects of first and second language on segmentation of non-native speech

Do Slovak-German bilinguals apply native Slovak phonological and lexical knowledge when segmenting German speech? When Slovaks listen to their native language, segmentation is impaired when fixed-stress cues are absent (Hanulíková, McQueen & Mitterer, 2010), and, following the Possible-Word Constraint (PWC; Norris, McQueen, Cutler & Butterfield, 1997), lexical candidates are disfavored if segmentation leads to vowelless residues, unless those residues are existing Slovak words. In the present study, fixed-stress cues on German target words were again absent. Nevertheless, in support of the PWC, both German and Slovak listeners recognized German words (e.g., Rose "rose") faster in syllable contexts (suckrose) than in single-consonant contexts (krose, trose). But only the Slovak listeners recognized, for example, Rose faster in krose than in trose (k is a Slovak word, t is not). It appears that non-native listeners can suppress native stress segmentation procedures, but that they suffer from prevailing interference from native lexical knowledge.peer-reviewe