Articulating: the neural mechanisms of speech production

Speech production is a highly complex sensorimotor task involving tightly coordinated processing across large expanses of the cerebral cortex. Historically, the study of the neural underpinnings of speech suffered from the lack of an animal model. The development of non-invasive structural and functional neuroimaging techniques in the late 20th century has dramatically improved our understanding of the speech network. Techniques for measuring regional cerebral blood flow have illuminated the neural regions involved in various aspects of speech, including feedforward and feedback control mechanisms. In parallel, we have designed, experimentally tested, and refined a neural network model detailing the neural computations performed by specific neuroanatomical regions during speech. Computer simulations of the model account for a wide range of experimental findings, including data on articulatory kinematics and brain activity during normal and perturbed speech. Furthermore, the model is being used to investigate a wide range of communication disorders.R01 DC002852 - NIDCD NIH HHS; R01 DC007683 - NIDCD NIH HHS; R01 DC016270 - NIDCD NIH HHSAccepted manuscrip

Ten Economic Facts About Crime and Incarceration in the United States

Crime and high rates of incarceration impose tremendous costs on society, with lasting negative effects on individuals, families, and communities. Rates of crime in the United States have been falling steadily, but still constitute a serious economic and social challenge. At the same time, the incarceration rate in the United States is so high -- more than 700 out of every 100,000 people are incarcerated -- that both crime scholars and policymakers alike question whether, for nonviolent criminals in particular, the social costs of incarceration exceed the social benefits

Is a Modified Dialectical Behavior Therapy (DBT) Regimen Effective in Reducing PTSD Symptom Severity in Adult Women with Comorbid PTSD and BPD?

OBJECTIVE: The objective of this selective EBM review is to determine whether or not “a modified dialectical behavior therapy (DBT) regimen is effective in reducing PTSD symptom severity in adult women with comorbid PTSD and BPD?” STUDY DESIGN: Review of two randomized controlled trials (RCTs) and one case study published in English between 2013-2015. DATA SOURCES: Two RCTs and one case study found via PubMed and Google Scholar evaluated the benefit of a modified dialectical behavior therapy (DBT) in reducing PTSD symptom severity in patients with comorbid PTSD and BPD. OUTCOMES MEASURED: PTSD Symptom severity was measured via the Clinician- Administered PTSD Scale (CAPS), PTSD Symptom Scale – Interview (PSS-I), and PTSD Checklist (PCL). RESULTS: Both RCT’s performed by Bohus et al. (Psychother Psychosom. 2013;82(4):221223. doi: 10.1159/000348451) and Harned et al. (Behav Res Ther. 2014;55:7-17. doi: 10.1016/j.brat.2 014.01.008) found a statistically significant relationship between a modified DBT regimen, DBT-PTSD or DBT + DBT PE respectively, and a marked reduction in PTSD symptom severity as compared to the control group. Granato et al. (J. Clin. Psychol. 2015;71:805 -815. doi: 10.100 2/jclp/22207) conducted a case study that descriptively revealed the patient’s reduced PTSD symptomatology after completing DBT + DBT PE yet is deficient in its ability to produce significant data due to their lack of sample size. CONCLUSIONS: The reported evidence in each study supports the efficacy of a modified DBT regimen in the marked reduction of PTSD symptom severity in adult women with co-occurring PTSD and BPD. However, only the two RCTs by Bohus et al and Harned et al. elicited data with statistical significance. Based on the findings from these two trials, it is evident that women who severely suffer from both mental illnesses are capable of reducing their PTSD symptomatology with potential remission from one of the diagnoses after completion of a modified DBT treatment, as compared to traditional DBT that is unable to elicit the same change. These studies prove that it is imperative to simultaneously target both symptomatic manifestations of BPD and PTSD that co-occur and cause significant impairment. Future research should focus on expanding sample sizes and lengthening follow-up measures to assess the treatment’s long-term impact on psychological remission

Trends in U. S. Wage Inequality: Re-Assessing the Revisionists

A large literature documents a substantial rise in U. S. wage inequality and educational wage differentials over the past several decades and finds that these trends can be primarily accounted for by shifts in the supply of and demand for skills reinforced by the erosion of labor market institutions affecting the wages of low- and middle-wage workers. Drawing on an additional decade of data, a number of recent contributions reject this consensus to conclude that (1) the rise in wage inequality was an “episodic” event of the first-half of the 1980s rather than a "secular” phenomenon, (2) this rise was largely caused by a falling minimum wage rather than by supply and demand factors; and (3) rising residual wage inequality since the mid-1980s is explained by confounding effects of labor force composition rather than true increases in inequality within detailed demographic groups. We reexamine these claims using detailed data from the Current Population Survey and find only limited support. Although the growth of overall inequality in the U. S. slowed in the 1990s, upper tail inequality rose almost as rapidly during the 1990s as during the 1980s. A decomposition applied to the CPS data reveals large and persistent rise in within-group earnings inequality over the past several decades, controlling for changes in labor force composition. While changes in the minimum wage can potentially account for much of the movement in lower tail earnings inequality, strong time series correlations of the evolution of the real minimum wage and upper tail wage inequality raise questions concerning the causal interpretation of such relationships. We also find that changes in the college/high school wage premium appear to be well captured by standard models emphasizing rapid secular growth in the relative demand for skills and fluctuations in the rate of growth of the relative supply of college workers – though these models do not accurately predict the slowdown in the growth of the college/high-school gap during the 1990s. We conclude that these patterns are not adequately explained by either a ‘unicausal’ skill-biased technical change explanation or a revisionist hypothesis focused primarily on minimum wages and mechanical labor force compositional effects. We speculate that these puzzles can be partially reconciled by a modified version of the skill-biased technical change hypothesis that generates a polarization of skill demands.

Trends in U.S. Wage Inequality: Re-Assessing the Revisionists

A recent "revisionist " literature characterizes the pronounced rise in U.S. wage inequality since 1980 as an "episodic " event of the first-half of the 1980s driven by non-market factors (particularly a falling real minimum wage) and concludes that continued increases in wage inequality since the late 1980s substantially reflect the mechanical confounding effects of changes in labor force composition. Analyzing data from the Current Population Survey for 1963 to 2005, we find limited support for these claims. The slowing of the growth of overall wage inequality in the 1990s hides a divergence in the paths of upper-tail (90/50) inequality -- which has increased steadily since 1980, even adjusting for changes in labor force composition -- and lower tail (50/10) inequality, which rose sharply in the first-half of the 1980s and plateaued or contracted thereafter. Fluctuations in the real minimum wage are not a plausible explanation for these trends since the bulk of inequality growth occurs above the median of the wage distribution. Models emphasizing rapid secular growth in the relative demand for skills -- attributable to skill-biased technical change -- and a sharp deceleration in the relative supply of college workers in the 1980s do an excellent job of capturing the evolution of the college/high-school wage premium over four decades. But these models also imply a puzzling deceleration in relative demand growth for college workers in the early 1990s, also visible in a recent "polarization" of skill demands in which employment has expanded in high-wage and low-wage work at the expense of middle-wage jobs. These patterns are potentially reconciled by a modified version of the skill-biased technical change hypothesis that emphasizes the role of information technology in complementing abstract (high-education) tasks and substituting for routine (middle-education) tasks.

Rising Wage Inequality: The Role of Composition and Prices

During the early 1980s, earnings inequality in the U.S. labor market rose relatively uniformly throughout the wage distribution. But this uniformity gave way to a significant divergence starting in 1987, with upper-tail (90/50) inequality rising steadily and lower tail (50/10) inequality either flattening or compressing for the next 16 years (1987 to 2003). This paper applies and extends a quantile decomposition technique proposed by Machado and Mata (2005) to evaluate the role of changing labor force composition (in terms of education and experience) and changing labor market prices to the expansion and subsequent divergence of upper- and lower-tail inequality over the last three decades We show that the extended Machado-Mata quantile decomposition corrects shortcomings of the original Juhn-Murphy-Pierce (1993) full distribution accounting method and nests the kernel reweighting approach proposed by DiNardo, Fortin and Lemieux (1996). Our analysis reveals that shifts in labor force composition have positively impacted earnings inequality during the 1990s. But these compositional shifts have primarily operated on the lower half of the earnings distribution by muting a contemporaneous, countervailing lower-tail price compression. The steady rise of upper tail inequality since the late 1970s appears almost entirely explained by ongoing between-group price changes (particularly increasing wage differentials by education) and residual price changes.

The Polarization of the U.S. Labor Market

This paper analyzes a marked change in the evolution of the U.S. wage structure over the past fifteen years: divergent trends in upper-tail (90/50) and lower-tail (50/10) wage inequality. We document that wage inequality in the top half of distribution has displayed an unchecked and rather smooth secular rise for the last 25 years (since 1980). Wage inequality in the bottom half of the distribution also grew rapidly from 1979 to 1987, but it has ceased growing (and for some measures actually narrowed) since the late 1980s. Furthermore we find that occupational employment growth shifted from monotonically increasing in wages (education) in the 1980s to a pattern of more rapid growth in jobs at the top and bottom relative to the middles of the wage (education) distribution in the 1990s. We characterize these patterns as the %u201Cpolarization%u201D of the U.S. labor market, with employment polarizing into high-wage and low-wage jobs at the expense of middle-wage work. We show how a model of computerization in which computers most strongly complement the non-routine (abstract) cognitive tasks of high-wage jobs, directly substitute for the routine tasks found in many traditional middle-wage jobs, and may have little direct impact on non-routine manual tasks in relatively low-wage jobs can help explain the observed polarization of the U.S. labor market.

Rising Wage Inequality: The Role of Composition and Prices

During the early 1980s, earnings inequality in the U. S. labor market rose relatively uniformly throughout the wage distribution. But this uniformity gave way to a significant divergence starting in 1987, with upper-tail (90/50) inequality rising steadily and lower tail (50/10) inequality either flattening or compressing for the next 16 years (1987 to 2003). This paper applies and extends a quantile decomposition technique proposed by Machado and Mata (2005) to evaluate the role of changing labor force composition (in terms of education and experience) and changing labor market prices to the expansion and subsequent divergence of upper- and lower-tail inequality over the last three decades We show that the extended Machado-Mata quantile decomposition corrects shortcomings of the original Juhn-Murphy-Pierce (1993) full distribution accounting method and nests the kernel reweighting approach proposed by DiNardo, Fortin and Lemieux (1996). Our analysis reveals that shifts in labor force composition have positively impacted earnings inequality during the 1990s. But these compositional shifts have primarily operated on the lower half of the earnings distribution by muting a contemporaneous, countervailing lower-tail price compression. The steady rise of upper tail inequality since the late 1970s appears almost entirely explained by ongoing between-group price changes (particularly increasing wage differentials by education) and residual price changes.

Microbial community dynamics and coexistence in a sulfide-driven phototrophic bloom

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bhatnagar, S., Cowley, E. S., Kopf, S. H., Pérez Castro, S., Kearney, S., Dawson, S. C., Hanselmann, K., & Ruff, S. E. Microbial community dynamics and coexistence in a sulfide-driven phototrophic bloom. Environmental Microbiome, 15(1),(2020): 3, doi:10.1186/s40793-019-0348-0.Background: Lagoons are common along coastlines worldwide and are important for biogeochemical element cycling, coastal biodiversity, coastal erosion protection and blue carbon sequestration. These ecosystems are frequently disturbed by weather, tides, and human activities. Here, we investigated a shallow lagoon in New England. The brackish ecosystem releases hydrogen sulfide particularly upon physical disturbance, causing blooms of anoxygenic sulfur-oxidizing phototrophs. To study the habitat, microbial community structure, assembly and function we carried out in situ experiments investigating the bloom dynamics over time. Results: Phototrophic microbial mats and permanently or seasonally stratified water columns commonly contain multiple phototrophic lineages that coexist based on their light, oxygen and nutrient preferences. We describe similar coexistence patterns and ecological niches in estuarine planktonic blooms of phototrophs. The water column showed steep gradients of oxygen, pH, sulfate, sulfide, and salinity. The upper part of the bloom was dominated by aerobic phototrophic Cyanobacteria, the middle and lower parts by anoxygenic purple sulfur bacteria (Chromatiales) and green sulfur bacteria (Chlorobiales), respectively. We show stable coexistence of phototrophic lineages from five bacterial phyla and present metagenome-assembled genomes (MAGs) of two uncultured Chlorobaculum and Prosthecochloris species. In addition to genes involved in sulfur oxidation and photopigment biosynthesis the MAGs contained complete operons encoding for terminal oxidases. The metagenomes also contained numerous contigs affiliating with Microviridae viruses, potentially affecting Chlorobi. Our data suggest a short sulfur cycle within the bloom in which elemental sulfur produced by sulfide-oxidizing phototrophs is most likely reduced back to sulfide by Desulfuromonas sp. Conclusions: The release of sulfide creates a habitat selecting for anoxygenic sulfur-oxidizing phototrophs, which in turn create a niche for sulfur reducers. Strong syntrophism between these guilds apparently drives a short sulfur cycle that may explain the rapid development of the bloom. The fast growth and high biomass yield of Chlorobi-affiliated organisms implies that the studied lineages of green sulfur bacteria can thrive in hypoxic habitats. This oxygen tolerance is corroborated by oxidases found in MAGs of uncultured Chlorobi. The findings improve our understanding of the ecology and ecophysiology of anoxygenic phototrophs and their impact on the coupled biogeochemical cycles of sulfur and carbon.This work was carried out at the Microbial Diversity summer course at the Marine Biological Laboratory in Woods Hole, MA. The course was supported by grants from National Aeronautics and Space Administration, the US Department of Energy, the Simons Foundation, the Beckman Foundation, and the Agouron Institute. Additional funding for SER was provided by the Marine Biological Laboratory

Methyl Coenzyme M Reductase (mcrA) Gene Abundance Correlates with Activity Measurements of Methanogenic H2/CO2-Enriched Anaerobic Biomass

Biologically produced methane (CH4) from anaerobic digesters is a renewable alternative to fossil fuels, but digester failure can be a serious problem. Monitoring the microbial community within the digester could provide valuable information about process stability because this technology is dependent upon the metabolic processes of microorganisms. A healthy methanogenic community is critical for digester function and CH4 production. Methanogens can be surveyed and monitored using genes and transcripts of mcrA, which encodes the α subunit of methyl coenzyme M reductase – the enzyme that catalyses the final step in methanogenesis. Using clone libraries and quantitative polymerase chain reaction, we compared the diversity and abundance of mcrA genes and transcripts in four different methanogenic hydrogen/CO2 enrichment cultures to function, as measured by specific methanogenic activity (SMA) assays using H2/CO2. The mcrA gene copy number significantly correlated with CH4 production rates using H2/CO2, while correlations between mcrA transcript number and SMA were not significant. The DNA and cDNA clone libraries from all enrichments were distinctive but community diversity also did not correlate with SMA. Although hydrogenotrophic methanogens dominated these enrichments, the results indicate that this methodology should be applicable to monitoring other methanogenic communities in anaerobic digesters. Ultimately, this could lead to the engineering of digester microbial communities to produce more CH4 for use as renewable fuel