Stochastic dynamics of lexicon learning in an uncertain and nonuniform world.

We study the time taken by a language learner to correctly identify the meaning of all words in a lexicon under conditions where many plausible meanings can be inferred whenever a word is uttered. We show that the most basic form of cross-situational learning--whereby information from multiple episodes is combined to eliminate incorrect meanings--can perform badly when words are learned independently and meanings are drawn from a nonuniform distribution. If learners further assume that no two words share a common meaning, we find a phase transition between a maximally efficient learning regime, where the learning time is reduced to the shortest it can possibly be, and a partially efficient regime where incorrect candidate meanings for words persist at late times.

The shielding function of task rules in the context of task switching.

There is increasing evidence that task rules help shield the response against distractor interference. Here, the authors investigate the cognitive mechanisms underlying this assumed shielding function of task rules and how it is adjusted to changing task demands. In two experiments, participants switched between a noun categorization and an adjective categorization task.

Sequential modulation of cue use in the task switching paradigm.

In task switching studies, pre-cuing of the upcoming task improves performance, indicating preparatory activation of the upcoming task-set, and/or inhibition of the previous task-set. To further investigate cue-based task preparation, the authors presented both valid and invalid task cues in a task switching experiment involving three tasks. Consistent with previous findings, a validity effect in terms of higher reaction times on invalidly compared to validly cued tasks was obtained.

The impact of task rules on distracter processing: automatic categorization of irrelevant stimuli.

The goal of the study was to investigate whether task rules are automatically applied to irrelevant distracters. In three experiments, subjects categorized target words which were superimposed on distracter pictures. The categorization rule was arbitrary and the distracters were not relevant at any point during the experiment.

Intranasal immunization with synthetic peptides corresponding to the E6 and E7 oncoproteins of human papillomavirus type 16 induces systemic and mucosal cellular immune responses and tumor protection.

The E6 and E7 oncoproteins of the high-risk HPV type16 represent ideal targets for HPV vaccine development, they being consistently expressed in cervical cancer lesions. Since HPV-16 is primarily transmitted through genital mucosal route, mucosal immune responses constitute an essential feature for vaccination strategies against HPV-associated lesions. We present here evidence showing that mucosal immunization of mice by the intranasal route with a mixture of peptides E7(44-62) and E6(43-57) from the E7 and E6 oncoproteins of HPV-16, respectively, using a mutant cholera toxin adjuvant (CT-2*), primed strong antigen-specific cellular immune responses in systemic and mucosal tissues.

[Selected anthropometric findings in women with disorders of glucose tolerance with hypertension].

In a group of 26 women with an impaired glucose tolerance anthropometric measurements of basic somatometric characteristics were made with special attention to the subcutaneous fat distribution and compared the findings with the healthy Czech population. Changes in body build, BMI, subcutaneous body fat distribution were evaluated and the causality of the relationship between blood pressure and gluteofemoral and abdominal obesity was investigated. From the author's observations ensues that in the group of women with impaired glucose tolerance overweight was recorded, as compared with the normal population, disproportions in the circumferences of the trunk and extremities, an excessive percentage of body fat, well developed muscles.

T-lymphocytes detected by esterase technique in malignant tumours of the thyroid.

The authors studied the percentage of T-lymphocytes detected by means of acid non specific esterase technique in patients with malignant thyroid tumours. The lymphocytes were investigated in the punctates from the tumour as well as in the venous blood. The results were compared with those in simple goitres and in healthy controls respectively.

Effect of prednisolone on the rat bone calcium, phosphorus and magnesium concentration.

Adult male rats were given prednisolone (Urbason solubile = 6-methyl-prednisolone) in doses of 4 mg/100 g body weight for 10, 20 or 30 days and its effect on the calcium, phosphorus and magnesium content of their femurs was studied. At all the given intervals a statistically significant decrease in the magnesium content of the bone was found; the calcium content was significantly reduced only in the first phase of the experiment (at 10 days).

Effect of nifedipine on the adrenocortical and somatotrophic secretory reserve and TSH and thyroid hormone plasma levels.

The authors investigated the effect of one week's administration of therapeutic doses of the calcium antagonist nifedipine on the hormone homeostasis of clinically healthy subjects. The insignificant tendency towards an increase of the adrenocorticotrophic and somatotrophic secretory reserve and the unaltered levels of thyrotrophin, triiodothyronine and thyroxine rule out possible adverse side-effects of the administered therapeutic doses of nifedipine on the hormone balance of the mentioned systems. The authors discuss also the physiological impact of the assessed findings.