137 research outputs found

    Machine Learning for Mathematical Software

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    While there has been some discussion on how Symbolic Computation could be used for AI there is little literature on applications in the other direction. However, recent results for quantifier elimination suggest that, given enough example problems, there is scope for machine learning tools like Support Vector Machines to improve the performance of Computer Algebra Systems. We survey the authors own work and similar applications for other mathematical software. It may seem that the inherently probabilistic nature of machine learning tools would invalidate the exact results prized by mathematical software. However, algorithms and implementations often come with a range of choices which have no effect on the mathematical correctness of the end result but a great effect on the resources required to find it, and thus here, machine learning can have a significant impact.Comment: To appear in Proc. ICMS 201

    Comparison of the CES-D and PHQ-9 depression scales in people with type 2 diabetes in Tehran, Iran

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    <p>Abstract</p> <p>Background</p> <p>The quality of life in patients with various chronic disorders, including diabetes has been directly affected by depression. Depression makes patients less likely to manage their self-care regimens. Accurate assessment of depression in diabetic populations is important to the treatment of depression in this group and may improve diabetes management. To our best knowledge, there are few studies that have looked for utilizing questionnaires in screening for depression among patients with diabetes in Iran. Therefore the aim of this study was to assess the efficacy and accuracy of the Center for Epidemiological Studies Depression (CES-D) scale and the Patient Health Questionnaire-9 (PHQ-9), in comparison with clinical interview in people with type 2 diabetes.</p> <p>Methods</p> <p>Outpatients who attended diabetes clinics at IEM were recruited on a consecutive basis between February 2009 and July 2009. Inclusion criteria included patients with type 2 diabetes who could fluently read and speak Persian, had no severe diabetes complications and no history of psychological disorders. The history of psychological disorders was ascertained through patients' medical files, taking history of any medications in this regard. The study design was explained to all patients and informed consent was obtained. Volunteer patients completed the Persian version of the questionnaires (CES-D and PHQ-9) and a psychiatrist interviewed them based on Structured Clinical Interview (SCID) for DSM-IV criteria.</p> <p>Results</p> <p>Of the 185 patients, 43.2% were diagnosed as having Major Depressive Disorder (MDD) based on the clinical interview, 47.6% with PHQ-9 and 61.62% with CES-D. The Area Under the Curve (AUC) for the total score of PHQ-9 was 0.829 ± 0.30. A cut-off score for PHQ-9 of ≥ 13 provided an optimal balance between sensitivity (73.80%) and specificity (76.20%). For CES-D the AUC for the total score was 0.861 ± 0.029. Optimal balance between sensitivity (78.80%) and specificity (77.1%) was provided at cut-off score of ≥ 23.</p> <p>Conclusions</p> <p>It could be concluded that the PHQ-9 and CES-D perform well as screening instruments, but in diagnosing major depressive disorder, a formal diagnostic process following the PHQ-9 and also the CES-D remains essential.</p

    Extracellular NAD and ATP: Partners in immune cell modulation

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    Extracellular NAD and ATP exert multiple, partially overlapping effects on immune cells. Catabolism of both nucleotides by extracellular enzymes keeps extracellular concentrations low under steady-state conditions and generates metabolites that are themselves signal transducers. ATP and its metabolites signal through purinergic P2 and P1 receptors, whereas extracellular NAD exerts its effects by serving as a substrate for ADP-ribosyltransferases (ARTs) and NAD glycohydrolases/ADPR cyclases like CD38 and CD157. Both nucleotides activate the P2X7 purinoceptor, although by different mechanisms and with different characteristics. While ATP activates P2X7 directly as a soluble ligand, activation via NAD occurs by ART-dependent ADP-ribosylation of cell surface proteins, providing an immobilised ligand. P2X7 activation by either route leads to phosphatidylserine exposure, shedding of CD62L, and ultimately to cell death. Activation by ATP requires high micromolar concentrations of nucleotide and is readily reversible, whereas NAD-dependent stimulation begins at low micromolar concentrations and is more stable. Under conditions of cell stress or inflammation, ATP and NAD are released into the extracellular space from intracellular stores by lytic and non-lytic mechanisms, and may serve as ‘danger signals–to alert the immune response to tissue damage. Since ART expression is limited to naïve/resting T cells, P2X7-mediated NAD-induced cell death (NICD) specifically targets this cell population. In inflamed tissue, NICD may inhibit bystander activation of unprimed T cells, reducing the risk of autoimmunity. In draining lymph nodes, NICD may eliminate regulatory T cells or provide space for the preferential expansion of primed cells, and thus help to augment an immune response

    Assessing the Relationship between Leadership Styles and Organizational Health in Ilam's Teaching Hospitals in 2018

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    Background: leadership style is one of the factors affecting organizational health. Therefore, it has been considered as one of the clearest indicators of organizational effectiveness. Leadership is a part of nursing skills that plays an essential role in providing good health services. Aim: This study aimed to determine the relationship between leadership styles and organizational health in Nurses of Teaching Hospitals affiliated to Ilam University of Medical Sciences. Methods: This descriptive-correlational study was conducted on 110 nurses from Teaching Hospitals in Ilam, 2018. To collect data, an assessment battery including Bass and Avolio's Multifactor Leadership Questionnaire (2004) consisting of 45 items and Hoy and Tarter's Organizational Health Inventory (1997) consisting of 44 items were used. The data analysis was performed using descriptive statistics and analytical tests ( Pearson's and Spearman's correlation coefficients). Results: The findings demonstrated that the prevailing leadership style in the teaching hospitals was the transactional leadership style (2.95 +/- 0.72) and the organizational health level (97.38 +/- 21.89) was at an optimum level. Also, Pearson's correlation coefficient indicated a significant relationship between leadership styles and organizational health (p <0.005, r = 0.29). Regarding the direct relationship between leadership style and organizational health based on the results of this study, it can be suggested that nursing managers choose transactional leadership style and take steps toward its implementation in order to increase organizational health in their managed centers

    A Pore-Scale Investigation of the Transient Response of Forced Convection in Porous Media to Inlet Ramp Inputs

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    This paper investigates the transient response of forced convection of heat in a reticulated porous medium through taking a pore-scale approach. The thermal system is subject to a ramp disturbance superimposed on the entrance flow temperature/velocity. The developed model consisted of ten cylindrical obstacles aligned in a staggered arrangement with set isothermal boundary conditions. A few types of fluids, along with different values of porosity and Reynolds number are considered. Assuming a laminar flow, the unsteady Navier Stokes and energy equations are solved numerically. The temporally developing flow and temperature fields as well as the surface averaged Nusselt numbers are used to explore the transient response of the system. Further, a Response Lag Ratio (RLR) is defined to compare the transient response and the input. The results reveal that an increase in amplitude increases the RLR. Nonetheless, an increase in ramp duration decreases the RLR, particularly for high density fluids. Interestingly, it is found that Reynolds number has almost negligible effects upon RLP. This study clearly reflects the importance of conducting pore-scale analyses for understanding the transient response of heat convection in porous media

    Applied multi-criteria ideal rehabilitation model for budget allocation across road infrastructure

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    The solution of prioritization problem for budget allocation across road infrastructure rehabilitation projects is highly complicated. This complexity is often due to the contradictions exist in budget allocation process. Such process concerns allocation of rehabilitation funds across various road infrastructures and taking into account multiple evaluation criteria. Therefore, budget allocation is a complex process with too many contradictions in form of criteria or attributes. According to the Systematic Innovation methodology, solving a problem means removing a contradiction. This paper presents a decision support approach for management of budget in rehabilitation process of road infrastructure, introducing Applied Multi-Criteria Ideal Rehabilitation Model. To achieve this, with the help of multi-criteria decision analysis, the Degree of Ideality is introduced as a function of all criteria. "Ideality" is the measure of how close the system is to the ideal final result. If the useful feature improves or harmful feature lessens, the ideality improves. In order to maximize the Degree of Ideality in the proposed Model, contradictions and resources are identified and ideal final result is introduced. This will result in a simple mechanism for allocation of budget across all the road infrastructures need to be rehabilitated

    Successive melting and solidification of paraffin–alumina nanomaterial in a cavity as a latent heat thermal energy storage

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    Latent heat thermal energy storage (LHTES) plays a main role in many industrial applications, especially in high-powered electronics cooling systems and providing the thermal energy demand when the energy supply is unavailable. In this study, the LHTES cycle process, including successive melting and solidification, investigates in a two-dimensional annular space of a square cavity filled with nanomaterial of paraffin–alumina as a nanoPCM. In the melting process, all sidewalls of the cavity are insulated. Meanwhile, a constant heat rate generates homogeneously within the central heat source. At the end of melting, the heat generation gets off, while a time-reducing temperature lower than the paraffin melting point imposes on the sidewalls, and then, solidification triggers. The numerical simulation was accomplished using control volume method and the governing equations solved using the SIMPLE algorithm. The enthalpy-porosity method was employed to model the phase-change front. The value of thermal conductivity and the viscosity of the nanofluid have been experimentally measured before the numerical modeling. In this study, the effect of volume fraction of nanoparticles (0–0.03) has been investigated on the successive melting and solidification rate for a constant Rayleigh number of 5.74 × 105. The results show that adding nanoparticles to the PCM equal to the volume fractions of 0.01 and 0.02 improves melting rate, but the nanofluid with the volume fraction of 0.03 represents a poor heat transfer rate during melting even weaker than those for nanofluid with the volume fraction of 0.01. It also observed that the nanomaterial with the volume fraction of φ = 0.03 represents the highest solidification rate. However, taking the overall performance of successive melting and solidification system into account, the nanofluid with the volume fraction of 0.02 remarked the most effective heat transfer rate in comparison with the other examined cases

    On the unsteady forced convection in porous media subject to inlet flow disturbances-A pore-scale analysis

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    Heat convection response of a porous medium to the harmonic disturbances in the inlet flow is investigated in a configuration consisting of several obstacles. Navier Stokes and energy equations are solved computationally and the average Nusselt number around the obstacles is favourably compared against the existing empirical data. The Nusselt number fluctuations are then examined, revealing that the dynamical relations between the inlet flow fluctuations as the input and those of Nusselt number as the output, can be nonlinear. The extent of encountered nonlinearity is determined quantitatively through introduction of a measure of nonlinearity. It is shown that increases in the pore-scale Reynolds number can strengthen the nonlinearity. However, this is not a global trend and further increases in Reynolds number may push the system dynamics back to linear. Application of the concept of transfer function to the identified linear cases reveals that the frequency response of the Nusselt number closely resembles a classical low-pass filter. Further, through a statistical analysis, it is shown that thermal response of the porous medium is strongly dominated by those of the first few obstacles. This highlights the importance of taking pore-scale approach in the dynamical problems that involve heat convection in porous media

    Comparison of antibody titer against the infectious bursal disease virus following the disease with that obtained from live intermediate vaccines using indirect hemagglutination (IHA) test in broiler chicks

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    In this study, antibody titer obtained from the outbreak of the infection bursal disease (IBD) was compared with the titer obtained from live intermediate vaccines by indirect haemagglutination (IHA) test in broiler chicks. A total of 450 one day old Cobb chicks were divided into 3 groups each containing 150 chicks and were kept for 42 days in the same rearing conditions. Chicks in groups 1 and 2 received Bursin-2 and D-78 vaccines respectively via drinking water n days 14 and 21. The rest of the chicks were kept as the controls (group 4) and did not receive any vaccine against the IBD. Serum samples were collected from all birds 2 weeks after the second IBD vaccination. Additional 150 serum samples were also collected from 3 broiler flocks that were affected by IBD and had a history of vaccination by the previously mentioned method, two weeks after the last clinical sings were observed (group 3). Antibody titer of the samples against the IBD virus were determined by the IHA test and the results were evaluated using ANOVA and SPSS software. The mean antibody titer obtained from Bursin-2 and D-78 vaccines were 3.19 and 3.21 respectively which is less than the titer of 6 needed for protection against the disease. The antibody titer in affected flocks was 7.19. comparison of the mean titer of the two vaccines did not show any significant difference but there was significant difference between the titer obtained from each vaccine and that of the effected flock (
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