Weldability of a Nickel-based Superalloy

The electron beam welding process is used to investigate the weldability of the Ni-based superalloy Udimet 720LI. This is a modified form of the alloy Udimet 720, which has reduced concentrations of interstitial elements such as boron, silicon, and carbon. The history of high strength superalloys like this one suggests that welding will be difficult because of their tendency towards hot cracking during the welding process, or strain-age cracking during the post-weld aging process. Studies were done on several sizes of weldability test specimens to determine if Udimet 720LI will exhibit cracking tendencies. It was found that the alloy was not susceptible to hot cracking unless it had received the four-step aging heat treatment that is recommended by the manufacturer. It was also found that a restrained weldment is susceptible to strain-age cracking; however, if the weldment is allowed to deform then warpage can occur instead of cracking

Evaluating the Barrier Effect of a Major Highway on Movement and Gene Flow of the Northern Flying Squirrel

Roads are pervasive sources of habitat fragmentation around the world, affecting an estimated 19 percent of the land area of the coterminous United States (Forman 2000). The barrier effect of roads has been demonstrated for species from multiple taxa. Still, information DNA was extracted from cheek cells of 41 individuals and genotyped at 12 microsatellite loci to characterize patterns of population structure. Seven of 16 monitored squirrels crossed the highway at least once during their nightly movements. Randomization tests of the movement data do not indicate significant avoidance of crossing the highway corridor. Movement does not necessarily equate to gene flow, however, and forthcoming analysis of microsatellite data will help elucidate whether current rates of movement are sufficient to maintain genetic connectivity across the highway. regarding the response of the vast majority of species to roads is lacking. We examine the effects of a major roadway on the movement and population genetics of Northern flying squirrels (Glaucomys sabrinus) in the Cascade Mountains of Washington, USA. During 2009 and 2010, flying squirrels (n = 16) were trapped and radio-tracked to gather data on movement within their home ranges and to detect movement across the roadway. Additionally

Articulatory Rate and Stuttering

The effect of speech rate on stuttering frequency was investigated with 20 stutterers. Subjects read two different 300 syllable passages at a normal and fast speech rate. Stuttering counts and articulatory rate was determined for each speech sample. Articulatory rates were derived from portions of the passages which were perceptually fluent. No statistically significant difference in stuttering frequency was found between the two speech rate conditions (p = .16) while a significant difference was observed for articulatory rate (p = .0007). These findings suggest that increased articulatory rate does not determine stuttering frequency with the same consistency as does decreased articulatory rate. It was concluded that a single explanation of the relationship between speech rate and stuttering frequency in terms of speech timing complexity is inadequate

Self-Contained In-The-Ear Devise to Deliver AAF

The design and operating characteristics of the first self-contained in-the-ear device to deliver altered auditory feedback is described for applications with those who stutter. The device incorporates a microdigital signal processor core that reproduces the high fidelity of unaided listening and auditory self-monitoring while at the same time delivering altered auditory feedback. Delayed auditory feedback and frequency-altered feedback signals in combination or isolation can be generated to the user in a cosmetically appealing custom in-the-canal and completely in-the-canal design. Programming of the device is achieved through a personal computer, interface, and fitting software. Researchers and clinicians interested in evaluating persons who stutter outside laboratory settings in a natural environment and persons who stutter looking for an alternative or adjunct to traditional therapy options are ideal candidates for this technology. In both instances an inconspicuous ear level alternative to traditional body worn devices with external microphones and earphones is offered

Fluent Speech Via Visual Choral Speech

A novel phenomenon of fluency enhancement via visual gestures of speech in the absence of traditional auditory feedback is reported herein. The effect on visual choral speech on stuttering frequency was investigated. Ten participants who stuttered recited memorized text aloud under two conditions. In a Visual Choral Speech (VCS) condition participants were instructed to focus their gaze on the face, lips and jaw of a research assistant who "silently mouthed" the text in unison. In a control condition, participants recited memorized text to the research assistant who sat motionless. A statistically significant (p= .0025) reduction of approximately 80% in stuttering frequency was observed in the VCS condition. As visual linguistic cues are sufficient to activate the auditory cortex, one may speculate that VCS induces fluency in a similar yet undetermined manner as altered auditory feedback does

Stereotypes of Stutterers

The existence of a negative stereotype of stutterers among residents of three Small, rural communities in Newfoundland, Canada was investigated. Members of these communities (n=106) completed a 25 item semantic differential scale developed by Woods and Williams (1976) which asked them to rate a hypothetical adult male stutterer and nonstutterer. Results indicated that community members perceived hypothetical stutterers in a negative manner in comparison to nonstutterers, despite the fact that 85% of the respondents reported knowing stutterers and 39% reported being related to stutterers. It is suggested the negative stuttering stereotype exists because nonstutterers generalize state to trait anxiety, and because of the nature of the stuttering moment itself. Since this study and previous studies appear to show that the stereotype is not modified by exposure to stutterers, familial relationships, and/or educational background, further research is needed to determine what, if any factor, can modify the pervasive negative stereotype

Altered Auditory Feedback

The purpose of the study was to determine if combining delayed auditory feedback (DAF) and frequency altered feedback (FAF) would be more fluency enhancing than either DAF or FAF alone. Ten stutterers read at normal and fast speech rates under nonaltered auditory feedback (NAF), DAF (i.e., a 50 ms delay), FAF (i.e., a one half octave downward shift), and a combination of DAF and FAF [(COMBO), i.e., a 50 ms delay plus a one half octave downward shift]. Results indicated that stuttering frequency was significantly reduced under all altered auditory conditions at both speech rates relative to the NAF condition. There was, however, no significant differences between the altered auditory feedback conditions (i.e., DAF, FAF, and COMBO). It is suggested that further studies be undertaken to explore the combination of altered auditory feedback conditions, as it may be the case that a floor effect was demonstrated with the singular presentations of DAF and FAF and further improvements in fluency enhancement could not be exhibited in the combined condition. Finally, these findings support the notion that a slowed rate of speech is not necessary for fluency enhancement under conditions of altered auditory feedback

High-throughput sequencing and graph-based cluster analysis facilitate microsatellite development from a highly complex genome

Shah A, Schielzeth H, Albersmeier A, Kalinowski J, Hoffman J. High-throughput sequencing and graph-based cluster analysis facilitate microsatellite development from a highly complex genome. Ecology and Evolution. 2016;16(6):5718-5727.Despite recent advances in high-throughput sequencing, difficulties are often encountered when developing microsatellites for species with large and complex genomes. This probably reflects the close association in many species of microsatellites with cryptic repetitive elements. We therefore developed a novel approach for isolating polymorphic microsatellites from the club-legged grasshopper (Gomphocerus sibiricus), an emerging quantitative genetic and behavioral model system. Whole genome shotgun Illumina MiSeq sequencing was used to generate over three million 300 bp paired-end reads, of which 67.75% were grouped into 40,548 clusters within RepeatExplorer. Annotations of the top 468 clusters, which represent 60.5% of the reads, revealed homology to satellite DNA and a variety of transposable elements. Evaluating 96 primer pairs in eight wild-caught individuals, we found that primers mined from singleton reads were six times more likely to amplify a single polymorphic microsatellite locus than primers mined from clusters. Our study provides experimental evidence in support of the notion that microsatellites associated with repetitive elements are less likely to successfully amplify. It also reveals how advances in high-throughput sequencing and graph-based repetitive DNA analysis can be leveraged to isolate polymorphic microsatellites from complex genomes

High-throughput sequencing and graph-based cluster analysis facilitate microsatellite development from a highly complex genome

Shah A, Schielzeth H, Albersmeier A, Kalinowski J, Hoffman J. High-throughput sequencing and graph-based cluster analysis facilitate microsatellite development from a highly complex genome. Ecology and Evolution. 2016;16(6):5718-5727.Despite recent advances in high-throughput sequencing, difficulties are often encountered when developing microsatellites for species with large and complex genomes. This probably reflects the close association in many species of microsatellites with cryptic repetitive elements. We therefore developed a novel approach for isolating polymorphic microsatellites from the club-legged grasshopper (Gomphocerus sibiricus), an emerging quantitative genetic and behavioral model system. Whole genome shotgun Illumina MiSeq sequencing was used to generate over three million 300 bp paired-end reads, of which 67.75% were grouped into 40,548 clusters within RepeatExplorer. Annotations of the top 468 clusters, which represent 60.5% of the reads, revealed homology to satellite DNA and a variety of transposable elements. Evaluating 96 primer pairs in eight wild-caught individuals, we found that primers mined from singleton reads were six times more likely to amplify a single polymorphic microsatellite locus than primers mined from clusters. Our study provides experimental evidence in support of the notion that microsatellites associated with repetitive elements are less likely to successfully amplify. It also reveals how advances in high-throughput sequencing and graph-based repetitive DNA analysis can be leveraged to isolate polymorphic microsatellites from complex genomes