556 research outputs found

    A New Symmetric/Asymmetric Multilevel Inverter Based on Cascaded Connection of Sub-Multilevel Units Aiming less Switching Components and Total Blocked Voltage

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    In this paper, a new multilevel inverter is designed to improve the power and voltage quality, which contains a lesser number of switches in the specified voltage levels. The proposed inverter includes power electronic devices such as switches and diode, and DC inputs. In the proposed structure the desired output voltage can be produced by considering a series connection of a novel sub-multilevel module. This structure can be designed in both the symmetric and asymmetric topologies. The proposed structure has superior condition in terms of semiconductor switches and drivers count as well as switching loss. Additionally, the Total Blocked Voltage (TBV) of the proposed converter is compared with the conventional and the novel converters. This topology is studied by symmetric as well as asymmetric topologies through simulations in Matlab/Simulink environment as well as experiments by a laboratory prototype

    Occurrence of Campylobacter, Salmonella, and Arcobacter in pet birds of northern Iran

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    ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗPet birds can harbor human pathogens and contribute to the transmission of infectious agents to human. Since many people are interested in keeping pet birds, this study was conducted in pet birds from Mazandaran province, northern Iran. Totally, 174 fecal samples of pet birds (cockatiel, canary, lovebird, parrot, mynah, goldfinch, budgerigar, macaw, dove, pigeon, and bulbul) were collected with sterile cotton swabs and submitted to Faculty ofVeterinary Medicine, Department of Pathobiology (Amol, Iran). After extraction of total DNA, the samples subjected to molecular detection of the Campylobacter, Salmonella, and Arcobacter using polymerase chain reaction. A total of 114 (65.5%), 28 (16%), and 86 (49.4%) samples were found positive for Campylobacter, Salmonella, and Arcobacter, respectively. Furthermore, some birds showed contamination with two or all three of these bacteria. Results showed that mentioned bacteria can be detected from the apparently healthy pet birds. Therefore pet birds can be considered as potential carriers of these enteropathogens

    Generalization of Balian-Brezin decomposition for exponentials with linear fermionic part

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    Fermionic Gaussian states have garnered considerable attention due to their intriguing properties, most notably Wick's theorem. Expanding upon the work of Balian and Brezin, who generalized properties of fermionic Gaussian operators and states, we further extend their findings to incorporate Gaussian operators with a linear component. Leveraging a technique introduced by Colpa, we streamline the analysis and present a comprehensive extension of the Balian-Brezin decomposition (BBD) to encompass exponentials involving linear terms. Furthermore, we introduce Gaussian states featuring a linear part and derive corresponding overlap formulas. Additionally, we generalize Wick's theorem to encompass scenarios involving linear terms, facilitating the expression of generic expectation values in relation to one and two-point correlation functions. We also provide a brief commentary on the applicability of the BB decomposition in addressing the BCH (Zassenhaus) formulas within the so(N)\mathfrak{so}(N) Lie algebra.Comment: 21 page

    Role of histaminegic and calcium channels in the inhibitory effects of hydroalcoholic extract of matricaria recutita L. on isolated rabbit jejunum

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    Introduction: Considering the long traditional history of anti-inflammatory and anti-spasmodic effects of Matricria spices on the gastrointestinal system, the present study aimed to investigate the role of calcium channels and Histamine receptors in the inhibitory effects of hydroalcoholic dry extract of German chamomile (Matricaria recutita L.) on the isolated rabbit jejunum. Methods: All experiments were done on the isolated jejunum of New Zealand rabbits (1.8-2.5 kg). Dry extract of aerial parts of M. recutita was obtained by the maceration technique. The study was performed on two groups (n=6 in each group). In the first group, the effects of cumulative concentrations of M. recutita (3×10-3-1×10-2 mg/ml) on normal and K+-induced contractions (50 mM) of isolated jejunum were studied. In the second group, the inhibitory role of M. recutita (3 – 13×10-3 mg/ml) was evaluated in the presence and absence of histamine and cetrizine. In the presence and absence of 10 μM certizine, a histamine H1-antagonist, a concentration-dependent inhibitory effect of M. recutita extract in the range of 3-13×10-3 mg/ml was recorded the rabbit jejunum. Results: Results showed that EC50 of M. recutita in the absence and presence of K+ was 6.3×10-3 and 6.5×10- 3mg/ml, respectively. IC50 values for two concentrations of M. recutita (8×10-3 , 1×10-2 ) to abrogated contractive phase of Histamine was 9.55 × 10-6 and 1.57 × 10-6 μM. Cetrizine (10 μM) abolished inhibitory effects of M. recutita (IC50=3.6×10-3), (p< 0.001). Conclusion: Dry extract of matricaria recutita had inhibitory effects on the contractions of isolated rabbit jejunum. Calcium channels and histamine were involved in these antispasmodic effects

    Sandpiles Subjected to Sinusoidal Drive

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    This paper considers a sandpile model subjected to a sinusoidal external drive with the time period TT. We develop a theoretical model for the Green function in a large TT limit, which predicts that the avalanches are anisotropic and elongated in the oscillation direction. We track the problem numerically and show that the system shows additionally a regime where the avalanches are elongated in the perpendicular direction with respect to the oscillations. We find a transition point between these two regimes. The power spectrum of avalanche size and the grains wasted from the parallel and perpendicular directions are studied. These functions show power-law behaviour in terms of the frequency with exponents, which run with TT

    A Fast and Efficient Incremental Approach toward Dynamic Community Detection

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    Community detection is a discovery tool used by network scientists to analyze the structure of real-world networks. It seeks to identify natural divisions that may exist in the input networks that partition the vertices into coherent modules (or communities). While this problem space is rich with efficient algorithms and software, most of this literature caters to the static use-case where the underlying network does not change. However, many emerging real-world use-cases give rise to a need to incorporate dynamic graphs as inputs. In this paper, we present a fast and efficient incremental approach toward dynamic community detection. The key contribution is a generic technique called Δscreening\Delta-screening, which examines the most recent batch of changes made to an input graph and selects a subset of vertices to reevaluate for potential community (re)assignment. This technique can be incorporated into any of the community detection methods that use modularity as its objective function for clustering. For demonstration purposes, we incorporated the technique into two well-known community detection tools. Our experiments demonstrate that our new incremental approach is able to generate performance speedups without compromising on the output quality (despite its heuristic nature). For instance, on a real-world network with 63M temporal edges (over 12 time steps), our approach was able to complete in 1056 seconds, yielding a 3x speedup over a baseline implementation. In addition to demonstrating the performance benefits, we also show how to use our approach to delineate appropriate intervals of temporal resolutions at which to analyze an input network

    The efficacy of ethanolic extract of lemon verbena on the skin infection due to Staphylococcus aureus in an animal model

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    Daily increasing of Staphylococcus aureus resistance to various antibiotics in particular penicillin and Methecilin has led the scientist to look fore new medicines in this area. In an in vitro laboratory studies, it has been demonstrated that ethanolic extract of Lemon verbena can prevent the growth of Staphylococcus aureus. In this study the efficacy of ethanolic extract of Lemon verbena against Staphylococcus aureus skin infection were assessed in an in vivo, in animal model. 200λ of Staphylococcus aureus suspension, were inoculated intradermally on the shoulder of 63 laboratory 20-30 g mice. the mice were divided in to 4 groups, 2 control groups: Negative (without treatment) and positive(treated with Mupirucin) and 2 test groups that treated for 7 days by ointment prepared from ethanolic extract of Lemon verbena (group3), or injection of Lemon verbena solution (group 4). The status of wounds, the rate of recovery was studied and the presence of local pus after dissection of mice on day 8 recorded and compared with each other. The wound appearance in the second day, on the injection site of S. aureus, in Group 1, 4, 3 and 2 were 84.2, 66.7, 46.2 and 23.1%, respectively. In the final day, the lesion still was remained in 78.9, 23.1, 92.3 and 77.7% in groups 1 -4, respectively. The necrotic and wide wounds were more observed in groups 1 and 3 vs two other groups. The results from this investigation indicate that the ointment prepared from ethanolic extract of Lemon verbena is a proper medication to prevent the skin infection by Staphylococcus aureus in early phase. © 2007 Asian Network for Scientific Information
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