3,190 research outputs found

    Population size, habitat and conservation status of an Endangered species, Macrozamia johnsonii (Zamiaceae)

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    Macrozamia johnsonii D. Jones & K. Hill is a locally endemic cycad (family Zamiaceae) with a restricted occurrence in north-eastern New South Wales and currently listed as Endangered. Based on recent field surveys, its mean population size is estimated as approximately 3.5 million mature plants, with the lower bound of the 95% confidence interval at 1.9 million mature plants. Thirty percent of the population occurs in a formal reserve. Macrozamia johnsonii occurs in grassy eucalypt forest, shrubby wet sclerophyll forest and in rainforest. It occurs most frequently on steeply sloping sites with high moisture index. There are no immediate significant threats to the species although timber harvesting is judged to be a potential longer term threat to part of the population. The conservation status of Macrozamia johnsonii is assessed using IUCN criteria and thresholds, using population size and extent data from this study and a plausible range of values based on available circumstantial evidence for parameters for which quantitative estimates are not available. Based on this assessment, we regard the conservation status of Macrozamia johnsonii to be in the category of Least Concern, and that its current listing as an Endangered species under the NSW Threatened Species Conservation Act (1995) needs to be revised

    Are There Differences in Vocal Parameters Across Various Ethnic Groups?

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    The purpose of this study was to investigate vocal characteristics of various ethnic groups in terms of acoustic, physiological, and perceptual data. Currently there are acoustic parameter norms that have been established for men and women. Prior research suggested that these norms were established on only American Caucasian individuals. This creates the question as to whether or not these norms are reflective of the true nature of vocal fold closure pattern of all ethnic groups. If there is a difference in vocal characteristics then it would be important to establish specific norms for various ethnic groups. Further rationale for this investigation is that the demographic changes in the USA have signaled the need for greater understanding of treatment approaches for SLP and other health professionals. Secondly, establishing empirical evidence to support normative expectations for different groups may be helpful in understanding cultural expectations in treating voice disorders. Broadly speaking, I hypothesized that there would be a difference in fundamental frequency across ethnic groups. Specifically, there will be African-American participants that will demonstrate lower fundamental frequency parameters and that there will be differences in vocal fold behavior across the various ethnic groups. Fifteen individuals participated, one African-American male as well as three African-American females, two Asian males and one Asian female, three Caucasian males and two Caucasian females, one Hispanic male and two Hispanic females. Each participant underwent videostroboscopy for vocal fold observation. Additionally, aerodynamic vocal parameters were measured using the Visi-Pitch. All males demonstrated a posterior chink in their glottal closure pattern except for the Caucasian male group. There were no significant differences within acoustic measurements between the participants. When correlating the physiological and the acoustic data, it was demonstrated that the males with a posterior chink demonstrated a higher fundamental frequency compared to the males without a posterior chink. Currently there are no norm studies that have attempted to describe vocal fold closure across ethnic groups. The data identified in this study is relatively unexplored

    Montana Logging Costs: Resources for Continued Industry Viability

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    Montana’s logging industry has changed significantly over the past two decades. Increased operating costs and subsequent diminishing returns, combined with a shifting paradigm in regards to active forest management have had significant impacts on the economic and demographic make-up of the industry. One way to address these changes and mitigate the associated challenges of continued viability is through analysis of the factors and constraints impacting routine operational costs. Two methods were employed to estimate regional logging costs and changes over time. First, to provide a resource for comparison between commonly-utilized logging equipment, the hourly owning and operating costs of select mechanical, ground-based machines were calculated using the machine rate method from data supplied by western Montana equipment dealers. Second, an expert opinion survey of Montana and Idaho loggers was conducted, asking respondents to provide a simulated bid for a harvest unit typical of this region. The results from each method were compared to historic cost data, and reasons for increased logging expense were studied and discussed for fixed and variable cost categories, as were the impacts of changing operating conditions on costs. Results from the machine rate analysis suggest that inflation-adjusted operating costs for ground-based equipment are 47-93% higher than 20 years ago. Expert opinion survey results suggest that though costs are increasing, loggers are bidding at levels lower than actual costs merely to stay in business. Research on the reasons for these increases showed that costs have increased across certain fixed and variable categories, namely in equipment purchase price, fuel, labor wages and benefits, and repair/maintenance expense. Further, the number of operational days per year has decreased, administrative costs have increased, and there is increasing concern over volatile market conditions and the uncertainty over guaranteed future work. Clearly, this situation should be of considerable concern to those interested in retaining this sector in Montana. Vigilant consideration of operating costs and productivity will become increasingly critical to maintaining current infrastructure and helping to ensure the future of active forest management in Montana

    Are There Differences in Vocal Parameters Across Various Ethnic Groups?

    Get PDF
    The purpose of this study was to investigate vocal characteristics of various ethnic groups in terms of acoustic, physiological, and perceptual data. Currently there are acoustic parameter norms that have been established for men and women. Prior research suggested that these norms were established on only American Caucasian individuals. This creates the question as to whether or not these norms are reflective of the true nature of vocal fold closure pattern of all ethnic groups. If there is a difference in vocal characteristics then it would be important to establish specific norms for various ethnic groups. Further rationale for this investigation is that the demographic changes in the USA have signaled the need for greater understanding of treatment approaches for SLP and other health professionals. Secondly, establishing empirical evidence to support normative expectations for different groups may be helpful in understanding cultural expectations in treating voice disorders. Broadly speaking, I hypothesized that there would be a difference in fundamental frequency across ethnic groups. Specifically, there will be African-American participants that will demonstrate lower fundamental frequency parameters and that there will be differences in vocal fold behavior across the various ethnic groups. Fifteen individuals participated, one African-American male as well as three African-American females, two Asian males and one Asian female, three Caucasian males and two Caucasian females, one Hispanic male and two Hispanic females. Each participant underwent videostroboscopy for vocal fold observation. Additionally, aerodynamic vocal parameters were measured using the Visi-Pitch. All males demonstrated a posterior chink in their glottal closure pattern except for the Caucasian male group. There were no significant differences within acoustic measurements between the participants. When correlating the physiological and the acoustic data, it was demonstrated that the males with a posterior chink demonstrated a higher fundamental frequency compared to the males without a posterior chink. Currently there are no norm studies that have attempted to describe vocal fold closure across ethnic groups. The data identified in this study is relatively unexplored

    A Comprehensive Trainable Error Model for Sung Music Queries

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    We propose a model for errors in sung queries, a variant of the hidden Markov model (HMM). This is a solution to the problem of identifying the degree of similarity between a (typically error-laden) sung query and a potential target in a database of musical works, an important problem in the field of music information retrieval. Similarity metrics are a critical component of query-by-humming (QBH) applications which search audio and multimedia databases for strong matches to oral queries. Our model comprehensively expresses the types of error or variation between target and query: cumulative and non-cumulative local errors, transposition, tempo and tempo changes, insertions, deletions and modulation. The model is not only expressive, but automatically trainable, or able to learn and generalize from query examples. We present results of simulations, designed to assess the discriminatory potential of the model, and tests with real sung queries, to demonstrate relevance to real-world applications

    Posterior cortical atrophy: visuomotor deficits in reaching and grasping

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    Posterior Cortical Atrophy (PCA) is a rare clinical syndrome characterized by the predominance of higher-order visual disturbances such as optic ataxia, a characteristic of Balint's syndrome. Deficits result from progressive neurodegeneration of occipito-temporal and occipito-parietal cortices. The current study sought to explore the visuomotor functioning of four individuals with PCA by testing their ability to reach out and grasp real objects under various viewing conditions. Experiment 1 had participants reach out and grasp simple, rectangular blocks under visually- and memory-guided conditions. Experiment 2 explored participants' abilities to accurately reach for objects located in their visual periphery. This investigation revealed that PCA patients demonstrate many of the same deficits that have been previously reported in other individuals with optic ataxia, such as “magnetic misreaching”—a pathological reaching bias toward the point of visual fixation when grasping peripheral targets. Unlike many other individuals with optic ataxia, however, the patients in the current study also show symptoms indicative of damage to the more perceptual stream of visual processing, including abolished grip scaling during memory-guided grasping and deficits in face and object identification. These investigations are the first to perform a quantitative analysis of the visuomotor deficits exhibited by patients with PCA. Critically, this study helps characterize common symptoms of PCA, a vital first step for generating effective diagnostic criteria and therapeutic strategies for this understudied neurodegenerative disorder

    A comparison of optical and radar measurements of mesospheric winds and tides

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    Optical measurements of mesospheric winds by Fabry‐Perot spectrometers, FPSs, at Mawson, 67.6°S 62.9°E, and Davis, 68.6°S 78.0°E, Antarctica are compared with similar measurements obtained using a spaced‐antenna MF radar at Davis. The FPSs observed the OH emission. Different analysis procedures, used to determine the mean wind, and amplitude and phase of the semidiurnal tide, have been compared. At these latitudes the diurnal tide is weak and the semi‐diurnal tide, although highly variable in amplitude, is usually the dominant periodicity. When comparing the amplitude and phase of the semidiurnal tide good agreement is obtained between measurements by the two instruments
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