Dragonflies as an Important Aquatic Predator Insect and Their Potential for Control of Vectors of Different Diseases

Mosquitoes belong to order of Diptera. The main important vectors are genus Aedes, Culex and Anopheles. They transmit different agents such bacteria, viruses, and parasites. According to the latest information around 7 hundred million people around the world are suffering from mosquitoborne illness resulting over one million deaths. The main important disease transmitted by Anopheles is malaria. Other genus of mosquitoes including Aedes and Culex species transmit different arboviral disease to human. According to guideline of World Health Organization, the mina control of disease is vectors control. The main important vector control is using different insecticides. Using chemical insecticides for controlling mosquitoes is limited because they develop resistance against these insecticides. So, efforts have been made to control the mosquito vectors by eco-friendly techniques. In this research all, the relevant information regarding the topic of research is research through the internet and used in this paper. An intensive search of scientific literature was done in “PubMed”, “Web of Knowledge”, “Scopus”, “Google Scholar”, “SID”, etc Results shows that one of important environmental friendly vector control is biological control, using different predators and other microorganisms for vector and pest control. Dragonflies do eat mosquitos and serve as mosquito predators. They feed on mosquitos and reduce their number in outdoor areas. The dragonflies are scary biters, but they are dangerous to mosquitos. Worldwide results showed that dragonflies are able to control Aedes, Culex and Anopheles mosquito species. The artificial rearing of these predators and releasing for biological control is an appropriate measure for vector control worldwide

Malaria elimination in Iran, importance and challenges

Background: The aim of study is to assess the importance and challenges of Malaria elimination (ME) in Iran's health system. Material: Opinion of experts from Ministry of Health and Medical Education and the chancellors of medical universities affected by malaria were gathered using Focus Group Discussions and in­depth interviews. We asked them about the importance and main challenges of ME in Iran. Results: Main factors on importance of ME were: it's a struggle to reach to equity in the poorest regions of county, prevention of emerging disease in susceptible regions, lowering the cost of control and its effects on the region's socioeconomic condition. Main challenges were Iran's long border with malaria­endemic countries Pakistan and Afghanistan and illegal immigrants, underdevelopment in rural areas, system's insensitivity and diagnosis problem due to reduction of cases. Conclusion: Quantitative and holistic researches are needed for assessing the consequences of ME

Compression Mode Characterizations of Magnetorheological Elastomers

Magnetorheological (MR) elastomers (MREs) with controllable stiffness and damping properties offer significant potential for fail-safe semi-active and active control of vibration in many engineering applications. While the properties of MREs in the shear mode have been widely characterized, the compression mode properties of the MREs have been addressed in fewer studies. Unlike the shear mode, the compression mode characterization necessitates compensation for the magnetic force developed by the electromagnet in order to extract viscoelastic force from the measured force. In this dissertation research, a systematic methodology and a mathematical model are developed for compensating for the magnetic force for extracting the viscoelastic component of the force attributed to compression mode viscoelasticity of the MRE. For this purpose, an optimal design of a UI-shaped electromagnet was realized with minimum mass and magnetic flux density up to 1 Tesla. An experiment was designed to apply magnetic field in the direction of mechanical loading and to facilitate measurement of magneto-mechanical force. Results revealed peak errors in equivalent stiffness and damping constants of the MRE in the orders of 90% and 163%, respectively, in the absence of magnetic force compensation. The proposed compensation methodology provided a framework for accurate compression mode characterizations of the MREs as functions of the volume fraction and anisotropy of iron particles, and shape factor apart from the magnetic flux density, pre-strain and strain amplitude and strain rate excitations. MREs typically experience large static pre-strain in many applications in order to support the machine/structure weight, which can alter the distances among the magnetizable particles and thus the MR effect. The dynamic compression mode properties of isotropic and anisotropic MREs with 30% volume fraction of iron-particles and nominal shape factor (SF) of 0.56 were experimentally characterized under broad ranges of strain amplitude (2.5–20%) superimposed on a large static pre-strain of 21%, excitation frequency (0.1–50 Hz) and magnetic flux density (0–750 mT). Subsequently, the experiments were designed to evaluate the effects of the shape factor (SF), pre-strain and particle volume fraction (PVF) on compression mode properties of the isotropic and anisotropic MREs under broad ranges of excitations and magnetic flux density. The measured data were analyzed to evaluate compression mode properties in terms of stress-strain characteristics, relative MR effect, equivalent stiffness, equivalent damping, and elastic and loss moduli as functions of the design factors (pre-strain, PVF, SF and anisotropy) and operating factors (strain amplitude, strain rate and the magnetic flux density). The results invariably, revealed hysteretic stress-strain characteristics with strongly nonlinear and coupled dependence on the various design and operating factors. Among the design factors considered, the PVF revealed greatest effects on the stiffening and dampening behaviors of the MREs. Increasing the SF and PVF generally resulted in substantially higher MR effect in view of the elastic modulus of the MREs. The relative MR effect, however, decreased with increase in the pre-strain. The influences of various design and operating factors on the compression mode properties of are thoroughly analyzed and discussed, which would serve as design guidance for the MREs in different engineering applications. Phenomenological models with only a few unknown parameters were further formulated to predict the SF-, pre-strain-, and PVF-dependent compression elastic and loss moduli of both types of MREs. The effectiveness of the models is demonstrated by comparing the model-predicted properties with the measured data over broad ranges of design and operating conditions

Domination Number of the Non-commuting Graph of Finite Groups

Let G be a non-abelian group. The non-commuting graph of group G, shown by ΓG, is a graph with the vertex set G \ Z(G), where Z(G) is the center of group G. Also two distinct vertices of a and b are adjacent whenever ab ≠ ba. A set S ⊆ V(Γ) of vertices in a graph Γ is a dominating set if every vertex v ∈ V(Γ) is an element of S or adjacent to an element of S. The domination number of a graph Γ denoted by γ(Γ), is the minimum size of a dominating set of Γ. </p><p>Here, we study some properties of the non-commuting graph of some finite groups. In this paper, we show that \gamma(\Gamma_G)<\frac{|G|-|Z(G)|}{2}. Also we charactrize all of groups G of order n with t = ∣Z(G)∣, in which $\gamma(\Gamma_{G})+\gamma(\overline{\Gamma}_{G})\in \{n-t+1,n-t,n-t-1,n-t-2\}.