2,215 research outputs found

    Aspects of the Life History of the Tadpole Madtom, Noturus gyrinus (Siluriformes: Ictaluridae), in Southern Illinois

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    Author Institution: Department of Zoology, Southern Illinois University at CarbondaleAspects of the life history of Noturus gyrinus were studied from collections and observations made at Dutchman Creek, Johnson County, Illinois, between 25 October 1982 and 21 April 1984, and from specimens collected from Silver and Sugar creeks, Clinton, Madison, and St. Clair counties, Illinois, in July and August, 1982. N. gyrinus grew in length at a decreasing rate and in weight at a nearly constant rate for at least three (females) or four years (males). The largest individuals observed were a 97.5-mm standard length (SL) male and a 78.1-mm SL female. Mean annual SL was not significantly different between sexes except that males were both longer and heavier than females at age 3 + . There were 4.5 times as many males as females at age 3+, although the overall sex ratio was nearly 1:1 in the total sample. Only 29% survived past their first year; 90.5% did not live past their second year. Individuals (78%) usually matured in two years (sexes combined), although about 5% of males and 17% of females matured in one year. Mature males were 55-mm SL or longer, and mature females 48-mm or longer at one year. Mature females examined for the presence of eggs ranged from 52.6 to 78.9-mm SL, and contained 48 to 323 (x = 151.3) mature ova. Lengths and weights of mature females 'were both significant (P < 0.05) predictors of the numbers of mature ova. Dipteran larvae (chironomids) and small crustaceans (mainly isopods) constituted the major portion of the annual diet of all size classes. Gut contents of five species of piscivorous fish were examined; no evidence of predation on N. gyrinus was found

    Sex-specific fundamental and formant frequency patterns in a cross-sectional study

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    An extensive developmental acoustic study of the speech patterns of children and adults was reported by Lee and colleagues [Lee et al., J. Acoust. Soc. Am. 105, 1455-1468 (1999)]. This paper presents a reexamination of selected fundamental frequency and formant frequency data presented in their report for 10 monophthongs by investigating sex-specific and developmental patterns using two different approaches. The first of these includes the investigation of age- and sex-specific formant frequency patterns in the monophthongs. The second, the investigation of fundamental frequency and formant frequency data using the critical band rate (bark) scale and a number of acoustic-phonetic dimensions of the monophthongs from an age- and sex-specific perspective. These acoustic-phonetic dimensions include: vowel spaces and distances from speaker centroids; frequency differences between the formant frequencies of males and females; vowel openness/closeness and frontness/backness; the degree of vocal effort; and formant frequency ranges. Both approaches reveal both age- and sex-specific development patterns which also appear to be dependent on whether vowels are peripheral or non-peripheral. The developmental emergence of these sex-specific differences are discussed with reference to anatomical, physiological, sociophonetic and culturally determined factors. Some directions for further investigation into the age-linked sex differences in speech across the lifespan are also proposed

    An Exploration of the Performance and Acoustic Characteristics of UAV-Scale Stacked Rotor Configurations

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    As interest grows in rotor- and propeller-driven electric vertical takeoff and landing (eVTOL) aircraft for the Urban Air Mobility market, there is a potential for previously studied concepts to reemerge due to the opportunities afforded by novel technologies and operating modes. One such concept is the stacked rotor, which consists of multiple co-rotating rotors positioned co-axially with a small axial offset. The goal of the work presented in this paper is to determine whether stacked rotors offer a compelling advantage for eVTOL aircraft in terms of both performance and acoustic characteristics. Results are presented for new experimental tests and computational modeling of multiple stacked rotor configurations, and comparisons are made with conventional rotor configurations. Testing of thirteen separate configurations each using the same blade shaperevealed a configuration that resulted in an increase in the rotor power loading efficiency by more than 7% and reduced noise by more than 3 dBA when compared with a conventional rotor with all blades located in the same rotational plane

    Applying Latent Class Analysis on Cancer Registry Data to Identify and Compare Health Disparity Profiles in Colorectal Cancer Surgical Treatment Delay

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    Context: Colorectal cancer (CRC) surgical treatment delay (TD) has been associated with mortality and morbidity; however, disparities by TD profiles are unknown. Objectives: This study aimed to identify CRC patient profiles of surgical TD while accounting for differences in sociodemographic, health insurance, and geographic characteristics. Design: We used latent class analysis (LCA) on 2005-2015 Tennessee Cancer Registry data of CRC patients and observed indicators that included sex/gender, age at diagnosis, marital status (single/married/divorced/widowed), race (White/Black/other), health insurance type, and geographic residence (non-Appalachian/Appalachian). Setting: The state of Tennessee in the United States that included both Appalachian and non-Appalachian counties. Participants: Adult (18 years or older) CRC patients (N = 35 412) who were diagnosed and surgically treated for in situ (n = 1286) and malignant CRC (n = 34 126). Main Outcome Measure: The distal outcome of TD was categorized as 30 days or less and more than 30 days from diagnosis to surgical treatment. Results: Our LCA identified a 4-class solution and a 3-class solution for in situ and malignant profiles, respectively. The highest in situ CRC patient risk profile was female, White, aged 75 to 84 years, widowed, and used public health insurance when compared with respective profiles. The highest malignant CRC patient risk profile was male, Black, both single/never married and divorced/separated, resided in non-Appalachian county, and used public health insurance when compared with respective profiles. The highest risk profiles of in situ and malignant patients had a TD likelihood of 19.3% and 29.4%, respectively. Conclusions: While our findings are not meant for diagnostic purposes, we found that Blacks had lower TD with in situ CRC. The opposite was found in the malignant profiles where Blacks had the highest TD. Although TD is not a definitive marker of survival, we observed that non-Appalachian underserved/underrepresented groups were overrepresented in the highest TD profiles. The observed disparities could be indicative of intervenable risk

    The Relationship Between Cumulative Risk and Promotive Factors and Violent Behavior Among Urban Adolescents

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    Resiliency theory posits that some youth exposed to risk factors do not develop negative behaviors due to the influence of promotive factors. This study examines the effects of cumulative risk and promotive factors on adolescent violent behavior and tests two models of resilience—the compensatory model and the protective model—in a sample of adolescent patients (14–18 years old; n = 726) presenting to an urban emergency department who report violent behavior. Cumulative measures of risk and promotive factors consist of individual characteristics and peer, family, and community influences. Hierarchical multiple regression was used to test the two models of resilience (using cumulative measures of risk and promotive factors) for violent behavior within a sample of youth reporting violent behavior. Higher cumulative risk was associated with higher levels of violent behavior. Higher levels of promotive factors were associated with lower levels of violent behavior and moderated the association between risk and violent behaviors. Our results support the risk‐protective model of resiliency and suggest that promotive factors can help reduce the burden of cumulative risk for youth violence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117187/1/ajcp9541.pd

    Mental Skills Training Limits the Decay in Operative Technical Skill under Stressful Conditions: Results of a Multisite, Randomized Controlled Study

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    Background Overwhelming stress in the operating room can lead to decay in operative performance, particularly for residents who lack experience. Mental skills training can minimize deterioration in performance during challenging situations. We hypothesized that residents trained on mental skills would outperform controls under increased stress conditions in the simulated operating room. Methods Residents from Indiana University enrolled voluntarily in this institutional review board–approved study. Residents were stratified according to baseline characteristics and randomized into a mental skills and control group. Both groups trained to proficiency in laparoscopic suturing, but only the mental skills group received mental skills training. After training, technical skill transfer was assessed under regular and stressful conditions on a porcine model. Performance was assessed using an objective suturing score. The Test of Performance Strategies was used to assess the use of mental skills. Data were combined and compared with data that had been collected at Carolinas Healthcare System because residents underwent the same protocol. Results A total of 38 residents completed all study elements. There were no differences in the effects observed between sites. We observed no group differences at baseline. The groups achieved similar technical performance at baseline, posttest, and transfer test under low-stress conditions, but the mental skills group outperformed the control group during the transfer test under high-stress conditions. Conclusion Our comprehensive mental skills curriculum implemented with surgery residents at two institutions was effective at minimizing the deterioration of resident technical performance under stressful conditions compared with controls. These results provide further evidence for the effectiveness of mental skills training to optimize surgery trainees’ technical performance during challenging clinical situations

    Robust Magnetic Polarons in Type-II (Zn,Mn)Te Quantum Dots

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    We present evidence of magnetic ordering in type-II (Zn, Mn) Te quantum dots. This ordering is attributed to the formation of bound magnetic polarons caused by the exchange interaction between the strongly localized holes and Mn within the dots. In our photoluminescence studies, the magnetic polarons are detected at temperatures up to ~ 200 K, with a binding energy of ~ 40 meV. In addition, these dots display an unusually small Zeeman shift with applied field (2 meV at 10 T). This behavior is explained by a small and weakly temperature-dependent magnetic susceptibility due to anti-ferromagnetic coupling of the Mn spins
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