Frequency-specificity and pattern-specificity of the buildup of auditory stream segregation

During repeating sequences of low (A) and high (B) tones in an ...ABAB... pattern, the likelihood of hearing two separate streams ( streaming ) increases with more repetitions of the patterns, a phenomenon referred to as buildup . Previous studies have shown that buildup is frequency specific (Anstis & Saida, 1985) and that its biasing effects decays over several seconds (Beauvois & Meddis, 1997). No study has examined whether the frequency specificity of buildup persists for such a long duration. To address these issues, Experiment 1 tested the decay of frequency-specific and non-frequency specific buildup. The results revealed that (1) frequency-specific buildup effects were strongest during short decay intervals and decayed with longer intervals, (2) non-frequency-specific buildup showed weaker buildup effects and less decay, and (3) both types of buildup had significant effects compared to a silence baseline comparison even after long decay intervals. It is assumed non-frequency-specific buildup involved mechanisms in a high-level auditory area not finely tuned to frequency and sensitive to complex features. Therefore, Experiment 2 tested whether mechanisms subserving buildup occur in areas of the auditory pathway sensitive to rhythmic pattern. The main results revealed that (1) frequency-specific and non-frequency specific buildup effects were both disrupted by rhythmic pattern irregularity given their effects were large without such irregularity, and (2) replicated all other aspects of Experiment 1. The results of both experiments confirmed the presence of a frequency-specific mechanism subserving buildup that may be longer-lasting than previously recognized and further supported the presence of non-frequency specific mechanisms that are also long-lasting. Additionally, buildup appeared to involve mechanisms in high-level auditory areas sensitive to rhythmic pattern. Taken together, this study demonstrated buildup is a complex process that involves multiple levels of analysis along the auditory pathway

Pediatric Obesity: Influence on Drug Dosing and Therapeutics

Obesity is an ongoing global health concern and has only recently been recognized as a chronic disease of energy homeostasis and fuel partitioning. Obesity afflicts 17% of US children and adolescents. Severe obesity (³120% of the 95th percentile of BMI-for-age, or a BMI of ³35 kg/m2) is the fastest growing subgroup and now approaches 6% of all US youth. Health consequences (e.g., type 2 diabetes, coronary heart disease) are related in a dose-dependent manner to severity of obesity. Since therapeutic interventions are less effective in severe obesity, prevention is a high priority. Treatment plans involving combinations of behavioral therapy, nutrition and exercise achieve limited success. Only one drug, orlistat, is FDA-approved for long-term obesity management in adolescents 12 years and older. As part of comprehensive medication management, clinicians should consider the propensity for a given drug to aggravate weight gain and to consider alternatives that minimize weight impact. Medication management must take into account developmental changes as well as pathophysiology of obesity and comorbidities. Despite expanding insight into obesity pathophysiology, there are gaps in its translation to therapeutic application. The historical construct of obesity as simply a fat storage disorder is fundamentally inaccurate. The approach to adjusting doses based solely on body size and extrapolating from therapeutic knowledge of adult obesity may be based on assumptions that are not fully substantiated. Classes of drugs commonly prescribed for comorbidities associated with obesity should be prioritized for clinical research evaluations aimed at optimizing dosing regimens in pediatric obesity

Cuando el descabezamiento del crimen organizado funciona: el caso del Clan del Golfo en Colombia

Un proceso de desmovilización con este grupo armado constituye una oportunidad que no debe perderse. Aprovechando la salida de las FARC y el proceso de paz con el ELN, puede llevar presencia estatal a todas las regiones del país y concretar el camino hacia la paz, escriben Juan David Gélvez y Michael Weintraub (Universidad de los Andes)

Effect of Contextual Speech Rate on Speech Comprehension

Despite an extensive history of study, the effects of phonetic context are only known to affect small units of speech (e.g., formant transitions, function words). Critical aspects of speech perception, however, occur at larger scales. The series of experiments reported here investigated the effects of contextual speech rate on perception of a large unit of speech, namely sentences. In particular, there was an effect of relative rate on sentence comprehension – the rate of a sentence compared to the average rate of all other sentences within the same conversation-length period of speech – such that relatively slow sentences were better comprehended than relatively fast sentences (Experiment 1); however, differences in perceptual learning between the relatively slow and the relatively fast rates accounted for the effect of relative rate (Experiment 2). The results of these studies, therefore, do not support an effect of contextual speech rate on sentence comprehension. Finally, based on the results of a modified version of Experiment 1 in which context sentences were replaced with non-speech sounds (i.e., 1-channel noise vocoded speech), exposure to temporal information was not sufficient for generalization of perceptual learning (Experiment 3). These experiments are a novel investigation into both the effects of phonetic context on sentence comprehension, and the efficacy of non-speech sounds on generalization of perceptual learning

Learning how (not) to fire a gun: combatant training and civilian victimization

What is the relationship between the type of training combatants receive upon recruitmentinto an armed group and their propensity to abuse civilians in civil war? Does military training or political training prevent or exacerbate the victimization of civilians by armed non-state actors? While the literature on civilian victimization has expanded rapidly, few studies have examined the correlation between abuse of civilians and the modes of training that illegal armed actors receive. Using a simple formal model, we develop hypotheses regarding this connection and argue that while military training should not decrease the probability that a combatant engages in civilian abuse, political training should. We test these hypotheses using a new survey consisting of a representative sample of approximately 1,500 demobilized combatants from the Colombian conflict, which we match with department-level data on civilian casualties. The empirical analysis conrms our hypotheses about the connection between training and civilian abuse and the results are robust to adding a full set of controls both at the department and at the individual level.civil war, civilian abuse, survey instrument, demobilized combatants

Do enzyme activities during decomposition follow predicted patterns? A test of the conceptual model of litter decay.

Surprisingly, there remains a paucity of research examining specific interactions between the relationship between microbial community behavior and plant litter chemistry during decomposition. A more mechanistic understanding of the relationship between these drivers will ultimately help determine the trajectory of litter decomposition and the conditions in which soils serve as either a source or sink for atmospheric C. In order to examine these relationships, a laboratory incubation was established using _Acer saccharum_ litter and a sandy soil (< 1.5% organic matter). Extracellular enzyme activities ([BETA]-glucosidase, N-acetyl glucosaminidase, leucine-amino peptidase, acid phosphatase, phenol oxidase, and peroxidase) were monitored on a consistent basis along with instantaneous rates of carbon dioxide production, microbial biomass (carbon and nitrogen) and phospholipid fatty acid biomarkers (PLFA), and nitrogen and phosphorus availability. Microbial biomass and microbial respiration peaked within the first week of the experiment. This was likely due to the high availability of water soluble substrates early in decay that can be obtained without the production of extracellular enzymes. [BETA]-glucosidase (BG), N-acetyl glucosaminadase (NAG), and acid phosphatase activities increased quickly following the first week and peaked within the first month (at approximately 15% mass loss). Leucine amino peptidase was not detected during the incubation, which may be due to its strong positive correlation with soil pH, while other hydrolytic enzymes tend to track concentrations of soil organic matter. Phenol oxidase and peroxidase activities were not measurable until the second month of the experiment (> 25% mass loss), likely following the depletion of more labile substrates. A second increase in BG activity was observed between Days 83-111, which may be due to an increase in the availability of cellulose that was previously shielded by lignin, since oxidative enzyme activity was first detected on Day 68. We also observed some shifts in microbial PLFAs along with enzyme activities during decomposition. Prior to the increases in enzyme activity we observed a high proportion of PLFA 18:1[omega]7c, which is a bacterial biomarker. As enzyme activities increased, we observed a decrease in this biomarker and an increase in 18:2[omega]6,9c, a fungal biomarker that was correlated with BG and NAG activity. We did not observe any clear relationships between PLFAs and lignolytic enzyme activity, however. Overall, we observed a distinct functional shift in microbial substrate use that may be associated with either changes in composition of the microbial community or community shifts in enzyme production

Is it wise to decapitate organised armed groups? The case of Colombia's Clan del Golfo

Demobilisation of this armed group is an opportunity not to be missed. In a context of FARC disarmament and a peace process with the ELN, the state can establish its presence throughout the country and smooth the road to peace, write Juan David Gélvez and Michael Weintraub (Universidad de los Andes)

Star Formation in Orion's L1630 Cloud: an Infrared and Multi-epoch X-ray Study

X-ray emission is characteristic of young stellar objects (YSOs) and is known to be highly variable. We investigate, via an infrared and multi-epoch X-ray study of the L1630 dark cloud, whether and how X-ray variability in young stellar objects is related to protostellar evolutionary state. We have analyzed 11 Chandra X-ray Observatory observations, obtained over the course of four years and totaling ~240 ks exposure time, targeting the eruptive Class I YSO V1647 Ori in L1630. We used 2MASS and Spitzer data to identify and classify IR counterparts to L1630 X-ray sources and identified a total of 52 X-ray emitting YSOs with IR counterparts, including 4 Class I sources and 1 Class 0/I source. We have detected cool (< 3 MK) plasma, possibly indicative of accretion shocks, in three classical T Tauri stars. A subsample of 27 X-ray-emitting YSOs were covered by 9 of the 11 Chandra observations targeting V1647 Ori and vicinity. For these 27 YSOs, we have constructed X-ray light curves spanning approximately four years. These light curves highlight the variable nature of pre-main sequence X-ray emitting young stars; many of the L1630 YSOs vary by orders of magnitude in count rate between observations. We discuss possible scenarios to explain apparent trends between various X-ray spectral properties, X-ray variance and YSO classification.Comment: Accepted for publication in ApJS; 52 pages, 20 figure

Suzaku Observation of Strong Fluorescent Iron Line Emission from the Young Stellar Object V1647 Ori during Its New X-ray Outburst

The Suzaku X-ray satellite observed the young stellar object V1647 Ori on 2008 October 8 during the new mass accretion outburst reported in August 2008. During the 87 ksec observation with a net exposure of 40 ks, V1647 Ori showed a. high level of X-ray emission with a gradual decrease in flux by a factor of 5 and then displayed an abrupt flux increase by an order of magnitude. Such enhanced X-ray variability was also seen in XMM-Newton observations in 2004 and 2005 during the 2003-2005 outburst, but has rarely been observed for other young stellar objects. The spectrum clearly displays emission from Helium-like iron, which is a signature of hot plasma (kT approx.5 keV). It also shows a fluorescent iron Ka line with a remarkably large equivalent width of approx. 600 eV. Such a, large equivalent width indicates that a part of the incident X-ray emission that irradiates the circumstellar material and/or the stellar surface is hidden from our line of sight. XMM-Newton spectra during the 2003-2005 outburst did not show a strong fluorescent iron Ka line ; so that the structure of the circumstellar gas very close to the stellar core that absorbs and re-emits X-ray emission from the central object may have changed in between 2005 and 2008. This phenomenon may be related to changes in the infrared morphology of McNeil's nebula between 2004 and 2008

Investigation of the Microstructural and Thermoelectric Properties of the (GeTe)0.95(Bi2Te3)0.05 Composition for Thermoelectric Power Generation Applications

In the frame of the current research, the p-type Bi2Te3 doped (GeTe)(0.95)(Bi2Te3)(0.05) alloy composed of hot pressed consolidated submicron structured powder was investigated. The influence of the process parameters (i.e., powder particles size and hot pressing conditions) on both reduction of the lattice thermal conductivity and electronic optimization is described in detail. Very high maximal ZT values of up to similar to 1.6 were obtained and correlated to the microstructural characteristics. Based on the various involved mechanisms, a potential route for further enhancement of the ZT values of the investigated composition is proposed.EC, FP7 PowerDriver Projec