713 research outputs found

    Plant Species Distribution Along Topographic Gradients in Tallgrass Prairies of Eastern Nebraska.

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    Plant species composition was evaluated along a slope gradient in two native tallgrass prairies of eastern Nebraska. Forb cover differed significantly (P\u3c0.05) along the topographic gradient at both sites, however, grass covered differed only at one site (P\u3c0.05). A site-by-site comparison by topographic location indicates significant differences between lower slopes for grass and between upper slopes for forbs. Big bluestem (Andropogon gerardii Vitman) dominated all topographic locations at both sites (average cover = 64%) with no significant differences in the topographic distribution. Kentucky bluegrass (Poa pratensis L.), little bluestem (Andropogon scoparius Michx.), false boneset Kuhnia eupatorioides L.) prairie wild rose (Rosa arkansana Porter), prairie violet (Viola pedatifida G. Don), and sedge (Carex L. spp.) also show the no significant topographic preference at either site. Mid-slope locations contained the greatest number of species that differed significantly along the topographic gradient. Leadplant (Amorpha canescens Pursh) and indiangrass (Sorghastrum nutans (L.) Nash) were the two most common species showing high canopy cover values in mid-slope locations at both sites. Significant topographic distributions were also noted for scoring rush (Equisetum lawvigatum A. Br.) at both sites and for finger coreopsis (Coreopsis palmata Nutt.) found only at one site. Flowering spurge (Euphobia corollate L.) and sideoats grama (Bouteloua curtipendula (Michx.) Torr.) were significantly higher on the hilltop locations of one site

    The equivalence of two tax processes

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    We introduce two models of taxation, the latent and natural tax processes, which have both been used to represent loss-carry-forward taxation on the capital of an insurance company. In the natural tax process, the tax rate is a function of the current level of capital, whereas in the latent tax process, the tax rate is a function of the capital that would have resulted if no tax had been paid. Whereas up to now these two types of tax processes have been treated separately, we show that, in fact, they are essentially equivalent. This allows a unified treatment, translating results from one model to the other. Significantly, we solve the question of existence and uniqueness for the natural tax process, which is defined via an integral equation. Our results clarify the existing literature on processes with tax

    Design and implementation of single bit error correction linear block code system based on FPGA

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    Linear block code (LBC) is an error detection and correction code that is widely used in communication systems. In this paper a special type of LBC called Hamming code was implemented and debugged using FPGA kit with integrated software environments ISE for simulation and tests the results of the hardware system. The implemented system has the ability to correct single bit error and detect two bits error. The data segments length was considered to give high reliability to the system and make an aggregation between the speed of processing and the hardware ability to be implemented. An adaptive length of input data has been consider, up to 248 bits of information can be handled using Spartan 3E500 with 43% as a maximum slices utilization. Input/output data buses in FPGA have been customized to meet the requirements where 34% of input/output resources have been used as maximum ratio. The overall hardware design can be considerable to give an optimum hardware size for the suitable information rate

    Impact of Innovative Learning Environment Based on Research Activities on Secondary School Student's Attitude Towards Research and Their Self-Efficacy.

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    Advanced and free learning environment coupled with the creative learning activities is assumed to be a motivational variable. In the present study, we applied an innovative learning strategy involving students in order to achieve positive impact on their attitude towards science, desire to learn science and future career choices. The study experiment was focused on enhancing the research skills of the students; apply knowledge for solving real world problems, positively changing the students’ attitude towards science, raising students’ self-efficacy and enhance positivism toward science related subjects. This research assumes that if the attitude and perception of post-secondary students is changed and made positive about science, then they might choose to study related science subjects forexample, mathematics, engineering and science at university level studies. Therefore, it will also impact students’ career choices after university studies and they might enter scientific careers. Our study focused on evaluating various changes in the attitude, desire and self-efficacy of participating students when traditional instruction is replaced through the innovative learning environment. A total of 120 students participated in our experiment where researchers assisted students to experience hands on different research activities. Pre and posttest were used to evaluate the change in students’ attitude and desire towards science, knowledge and self-efficacy. The study results have shown that significant changes in the performance of students’ for-example, student noticed positive attitude towards their own research abilities, desire to learn science, self-efficacy, learning and career choices. However, results did not show any differences based on gender as such.Qatar Universit

    A new 2D Hénon-logistic map for producing hyperchaotic behavior

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    Derived from the two-dimensional (2D) Hénon map and the one-dimensional (1D) Logistic map, this paper proposes a new 2D hyperchaotic map, called the 2D Hénon-Logistic map (2D-HLM). The dynamics of the 2D-HLM are investigated by means of equilibria, stability analysis, trajectory, Lyapunov exponent, and bifurcation diagram. Mathematical analysis reveals that the 2D-HLM has four unstable equilibria. Besides that, it has wide chaotic and hyperchaotic behaviors with very limited periodic windows. To evaluate the complexity performance of the 2D-HLM, Approximate entropy is used to analyze its time series. Consequently, the 2D-HLM exhibits extremely complex nonlinear behavior. With all of these attributes, the 2D-HLM would be very appropriate to produce a pseudo-random number generator that can be used in chaos-based cryptographic applications

    Optimization of capacity in non-Gaussian noise models with and without fading channels for sustainable communication systems

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    The highest rate at which information may be reliably sent via a communication link is known as its capacity. In the case of non-Gaussian noise, the capacity of the channel depends on the specific characteristics of the noise, which can cause severe errors and reduce the reliability of communication systems over a fading channel. The Gaussian mixture impulsive noise model (GMINM), which is a more general and flexible non-Gaussian model for impulsive noise, has been compared in this paper with the Middleton Class-A impulsive noise model (MCAINM) in terms of derived channel capacity normalized by channel bandwidth (C/BW) with and without Rayleigh fading (Rf) channels. It also investigated the trade-off between complexity and accuracy in modeling the impulsive noise using two simplified Middleton Class-A impulsive noise models based on derived C/BW. The derived C/BW of these models under various conditions, such as different signal-to-noise ratios and impulsive noise parameters and models, have been performed and evaluated using two different scenarios: the exact method and the semi-analytical method. When the impulsive noise parameters  and A are both near 0 in GMINM and MCAINM, respectively, the capacity of the impulsive noise channel is found to be equivalent to that of the Gaussian channel sustainable, as shown by the findings based on Monte-Carlo simulations. We have shown that when the impulsive noise decreases, the capacity increases in all models; however, the capacity of Gaussian noise is higher than the capacity of non-Gaussian noise, which in turn is higher than the capacity of non-Gaussian noise over the Rf channel overall values of SNR in dB. Moreover, multi-channel configuration introduces spatial diversity and multiplexing gains that have been proposed to sustainably optimize the ergodic capacity for the challenge case when the channel state information (CSI) is unknown at the transmitter in non-Gaussian noise over Rf channel. In today's rapidly evolving world, sustainable communication systems play a crucial role in ensuring efficient and responsible utilization of resources. As the demand for wireless communication continues to rise, it becomes imperative to optimize the capacity of communication channels, especially in scenarios involving non-Gaussian noise models and fading channels.

    Knowledge, experience and perceptions regarding Molar-Incisor Hypomineralisation (MIH) amongst Australian and Chilean public oral health care practitioners

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    BACKGROUND: Molar-Incisor Hypomineralisation (MIH) is a prevalent developmental defect of tooth enamel associated with a high burden of disease. The present study aimed to survey Australian and Chilean oral health care practitioners (OHCPs) working in public dental facilities and to compare their knowledge, clinical experience and perceptions about MIH. Findings would give insights about how current knowledge has penetrated into OHCPs working into the public systems. METHODS: A mixed-mode survey regarding MIH was carried out amongst Australian and Chilean OHCPs from the public sector. The survey required responses to questions regarding sociodemographics, clinical experience, perceptions, clinical management and preferences for further training. The level of knowledge regarding MIH was determined by Delphi methods for consensus. Data analysis utilised Chi-square, linear and logistic regression models using SPSS Ver. 22.0. RESULTS: The majority of respondents had observed MIH in their patients (88.6 %) and the level of knowledge regarding MIH was high in Australian participants (p = 0.03). Australian respondents felt more confident when diagnosing (OR 8.80, 95 % CI 2.49-31.16) and treating MIH-affected children (OR 4.56, 95 % CI 2.16-9.76) compared to Chilean respondents. Oral health therapists reported higher levels of confidence than Australian general dental practitioners when providing treatment to children with MIH (OR 7.53; 95 % CI 1.95-29.07). CONCLUSIONS: Continuing to update clinical guidelines may help practitioners increase their understanding when diagnosing and treating MIH-affected children. Dissemination of information and awareness regarding MIH is necessary in public clinics, and in particular Chilean general dental practitioners should be alerted to these factors

    COVID-19 Pandemic and Endemic Febrile Illnesses: The Dilemma of Exclusion and Diagnosis with Limited Capacities in Aden, Yemen

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    Background: In the beginning of May 2020, Aden was living a state of catastrophic events with the spread of COVID-19 pandemic with accompanying heavy raining season leading to increase of unexpected fever cases. Despite the limited diagnostic capacity, data on causes and trends of febrile illness can be valuable indicators of the causes and trends of fever problems in Aden at the time of COVID-19 pandemic. Objective: to analyze the available data on febrile illness reported in the “Cuban-Yemeni Hospital” in Aden during May-June 2020. Methods: This is a retrospective review of the available data from the hospital registry. Results: Out of 7385 febrile patients, there were 1208 confirmed Malaria cases (16.4%), 1786 clinically diagnosed Dengue cases (23.3%), 1855 clinically diagnosed Chikungunya (25%), 2023 cases of respiratory tract infections-RTI (26.6%) and only 613 probable COVID-19 cases (8.4%). The total deaths in this period was 63, most of them died due to respiratory problems. Conclusions: Malaria is  a problem of serious concern in Aden as 16% of fever in this study were confirmed by laboratory testing while Dengue and Chikungunya were reported frequently but the diagnosis is still based on clinical grounds. As the diagnostic capacity for COVID-19 was limited, the available data underestimated the COVID-19 problem. Keywords: COVID-19, Dengue, Chikungunya, Malaria, Fever, Aden, Yemen. DOI: 10.7176/JHMN/77-01 Publication date:July 31st 202

    Intrathoracic solitary fibrous tumor - an international multicenter study on clinical outcome and novel circulating biomarkers

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    Intrathoracic solitary fibrous tumor (SFT) is a rare disease. Radical resection is the standard of care. However, estimating prognosis and planning follow-up and treatment strategies remains challenging. Data were retrospectively collected by five international centers to explore outcome and biomarkers for predicting event-free-survival (EFS). 125 histological proven SFT patients (74 female; 59.2%; 104 benign; 83.2%) were analyzed. The one-, three-, five- and ten-year EFS after curative-intent surgery was 98%, 90%, 77% and 67%, respectively. Patients age (>/=59 vs. 10 cm vs. 5 vs. < 5 HR 3.91, CI 1.40-10.89, p = 0.009) were prognostic after univariate analyses. After multivariate analyses tumor-dignity and fibrinogen remained as independent prognosticators. Besides validating the role of age, tumor-dignity, tumor-size, stage and resection margins, we identified for the first time inflammatory markers as prognosticators in SFT
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