L'arme du droit

- Divulgação dos SUMÁRIOS das obras recentemente incorporadas ao acervo da Biblioteca Ministro Oscar Saraiva do STJ. Em respeito à Lei de Direitos Autorais, não disponibilizamos a obra na íntegra.- Localização na estante: 34 I85

Processing of low-probability sounds by cortical neurons. Nature neuroscience 6

Neuronal adaptation, the decline over time of neuronal responses during sensory stimulation, is ubiquitous in the brain. Adaptation contributes to cortical gain control 1 , enhances stimulus discriminability 2 and maximizes information transmission by matching the coding strategy to stimulus statistics 3 . Studies in both visual and auditory sensory areas have shown that adaptation is often stimulus-specific 2,4-11 . For example, neurons in auditory cortex, after having been presented with a repetitive, single-frequency tone for several minutes, show a specific decrease in response to subsequent test tones near that frequency 8 . Similarly, neurons in visual cortex, presented with a high-contrast 'adapting' stimulus of a certain orientation, show decreased responses specifically near that orientation 2, Studies of such stimulus-specific adaptation (SSA), in both visual and auditory modalities, usually use one of two experimental approaches. The first is a method that uses long adapting sequences followed later by test stimuli 4-8 . This approach does not mimic natural scenarios particularly well; in natural sounds, the common background (mimicked by the long adapting sequence) is often intermixed with rare events (mimicked by the test stimuli). Furthermore, the common background may itself be changing over time scales of seconds, requiring fast, online adaptation. The second approach addresses these concerns by using pairs of stimuli-an adapting stimulus followed by a test stimulus. By this method, it has been shown that in some cases SSA can occur rapidly 2,9,10 . Several lines of evidence suggest that, in fact, it is natural to interpret neuronal adaptation in terms of the statistics of the stimulus ensemble. First, visual neurons can adapt in real time to the statistical distribution of input stimuli, and this adaptation can serve to maximize information transmission; thus, neuronal adaptation is tightly linked to the notion of optimal neural coding 3 . Second, natural acoustic backgrounds are highly variable and change rapidly in a stochastic manner 12 . Therefore, an important step in mimicking a naturalistic soundscape scenario Processing of low-probability sounds by cortical neurons The ability to detect rare auditory events can be critical for survival. We report here that neurons in cat primary auditory cortex (A1) responded more strongly to a rarely presented sound than to the same sound when it was common. For the rare stimuli, we used both frequency and amplitude deviants. Moreover, some A1 neurons showed hyperacuity for frequency deviants-a frequency resolution one order of magnitude better than receptive field widths in A1. In contrast, auditory thalamic neurons were insensitive to the probability of frequency deviants. These phenomena resulted from stimulus-specific adaptation in A1, which may be a single-neuron correlate of an extensively studied cortical potential-mismatch negativity-that is evoked by rare sounds. Our results thus indicate that A1 neurons, in addition to processing the acoustic features of sounds, may also be involved in sensory memory and novelty detection. is to use probabilistic stimuli. Third, the sensitivity of the mammalian auditory system to stimulus statistics is exemplified by the mismatch negativity (MMN) In the present study, we used probabilistic stimuli to study adaptation in the auditory system. Our data, collected from both cortex and thalamus, provide evidence for a novel form of SSA that is present in primary auditory cortex but is absent in the auditory thalamus. This form of SSA is rapid, shows very high frequency sensitivity (hyperacuity) and is strongly dependent on the statistical properties of the stimulus ensemble. Furthermore, this form of SSA shares a large number of properties with the MMN, and we therefore propose that it is a neural correlate of MMN. RESULTS To demonstrate SSA in single neurons of cat primary auditory cortex Responses of A1 neurons in an oddball design To study the specific effect of probability on SSA, two frequencies were used in an oddball design protocol: tones with a devian

Evaluation of CHROMagar KPC for Rapid Detection of Carbapenem-Resistant Enterobacteriaceae▿

A new CHROMagar KPC medium was compared to MacConkey agar with carbapenem discs and PCR for the blaKPC gene for rapid detection of carbapenem-resistant Klebsiella pneumoniae. The sensitivity and specificity relative to PCR were 100% and 98.4%, respectively, for CHROMagar KPC and 92.7% and 95.9%, respectively, for MacConkey agar

Group B Streptococcus serotypes associated with different clinical syndromes: Asymptomatic carriage in pregnant women, intrauterine fetal death, and early onset disease in the newborn.

ObjectivesTo study Group B Streptococcus (GBS) isolates associated with different clinical syndromes: asymptomatic carriage in pregnant women, intrauterine fetal death (IUFD), and early onset disease (EOD) in the newborn.MethodsGBS isolates were collected from asymptomatic pregnant women admitted for labor, IUFD cases, and neonates with EOD. Serotypes and antibiotic susceptibilities were determined. Multilocus sequence typing (MLST) was performed to assess genetic epidemiology.ResultsGBS carriage rate was 26.1% (280/1074). The dominant serotype among asymptomatic pregnant women was VI [98/240 women (40.8%)], followed by serotypes III, V and IV in 42/240 (17.5%), 30/240 (12.5%) and 28/240 (11.7%) women, respectively. The dominant serotype in IUFD cases was serotype VI [10/13 (76.9%)]. In contrast the prevalent serotype among EOD cases was III [16/19 (84.2%)]. ST-1 was associated with IUFD [7/13 (53.8%)], ST-17 was associated with serotype III and EOD in the newborn 14/19 (73.7%)]. Erythromycin and clindamycin resistance reached 36.8%, 7.7% and 20.0%among EOD, vaginal carriage and IUFD, respectively.ConclusionsSerotypes VI and ST-1 were dominant among asymptomatic pregnant women and in IUFD cases while EOD was associated with serotype III and ST-17. Invasive mechanisms thus may differ between IUFD and EOD in the newborn and virulence may be related to capsule serotype. Resistance rates to erythromycin and clindamycin were high in EOD cases