226 research outputs found

    Some biological characteristics of the Batrachedra amydraula Meyrick (Lepidoptera: Batrachedridae) on main varieties of dry and semi-dry date palm of Iran

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    Although Iran is the leading producer of dates in the world, only 10% of its product is exported. One of the factors which limits exportation is postharvest pests. Lesser date moth (Batrachedra amydraula) is one of these postharvest pests. This pest is found in all date palm plantations of Iran. The biology of this pest has not been studied under laboratory conditions on main varieties of stored date in Iran. In this research some biological characteristics including survivorship, developmental time, fecundity, oviposition and postoviposition period, and longevity of adults on date palm varieties Zahedi, Ghasb, Rabbi, Deyri and a semi-artificial diet were studied. All experiments carried out at constant temperature room (30 ± 0.5 °C and 55 ± 5% r.h.). Highest survivorship of egg and combined larval and pupal stages were 86 and 85% respectively on semi-artificial diet. Shortest total development time from egg to adult was 43 days for males and 43 days for females on semi-artificial diet. Longest total development time was 69 days for male and 65 days for female on Ghasb variety. The highest (45 eggs per female) and lowest (25 eggs per female) fecundity occurred on the Deyri variety and semi-artificial diet, respectively. Results of this study would be useful for making pest management decisions in date palm storage.Keywords: Lesser date moth, Batrachedra amydraula, Biology, Date pal

    Friction compensation of an actively restrained clutch for path tracking

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    Friction compensation of an electromechanical friction clutch mechanism capable of restraining motion so that various predefined paths can be followed is investigated in this paper. The clutch mechanism is driven by an external source of energy, and a computer-controlled system is used to produce frictional resistance so that a desired motion can be achieved. Unknown stick-slip within the clutch is a critical characteristic of the system, which has to be overcome. Three different controllers are investigated in order to avoid stick-slip at low motion rates. A proportional-derivative controller, a sliding-mode controller, and a computed-torque controller, have been implemented and their performances compared using simulation and experimental analyses. The results demonstrate the effectiveness of the sliding-mode controller and the potential of a computed-torque controller for the motion control in a system with dry friction at low velocities

    Implementing a lightweight Schmidt-Samoa cryptosystem (SSC) for sensory communications

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    One of the remarkable issues that face wireless sensor networks (WSNs) nowadays is security. WSNs should provide a way to transfer data securely particularly when employed for mission-critical purposes. In this paper, we propose an enhanced architecture and implementation for 128-bit Schmidt-Samoa cryptosystem (SSC) to secure the data communication for wireless sensor networks (WSN) against external attacks. The proposed SSC cryptosystem has been efficiently implemented and verified using FPGA modules by exploiting the maximum allowable parallelism of the SSC internal operations. To verify the proposed SSC implementation, we have synthesized our VHDL coding using Quartus II CAD tool targeting the Altera Cyclone IV FPGA EP4CGX22CF19C7 device. Hence, the synthesizer results reveal that the proposed cryptographic FPGA processor recorded an attractive result in terms of critical path delay, hardware utilization, maximum operational frequency FPGA thermal power dissipation for low-power applications such as the wireless sensor networks

    Clustering and recommendation techniques for access control policy management

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    Managing access control policies can be a daunting process, given the frequent policy decisions that need to be made, and the potentially large number of policy rules involved. Policy management includes, but is not limited to: policy optimization, configuration, and analysis. Such tasks require a deep understanding of the policy and its building compo- nents, especially in scenarios where it frequently changes and needs to adapt to different environments. Assisting both administrators and users in performing these tasks is impor- tant in avoiding policy misconfigurations and ill-informed policy decisions. We investigate a number of clustering and recommendation techniques, and implement a set of tools that assist administrators and users in managing their policies. First, we propose and imple- ment an optimization technique, based on policy clustering and adaptable rule ranking, to achieve optimal request evaluation performance. Second, we implement a policy analysis framework that simplifies and visualizes analysis results, based on a hierarchical cluster- ing algorithm. The framework utilizes a similarity-based model that provides a basis of risk analysis on newly introduced policy rules. In addition to administrators, we focus on regular individuals whom nowadays manage their own access control polices on a regular basis. Users are making frequent policy decisions, especially with the increasing popular- ity of social network sites, such as Facebook and Twitter. For example, users are required to allow/deny access to their private data on social sites each time they install a 3rd party application. To make matters worse, 3rd party access requests are mostly uncustomizable by the user. We propose a framework that allows users to customize their policy decisions on social sites, and provides a set of recommendations that assist users in making well- informed decisions. Finally, as the browser has become the main medium for the users online presence, we investigate the access control models for 3rd party browser extensions. Even though, extensions enrich the browsing experience of users, they could potentially represent a threat to their privacy. We propose and implement a framework that 1) monitors 3rd party extension accesses, 2) provides fine-grained permission controls, and 3) Provides detailed permission information to users in effort to increase their privacy aware- ness. To evaluate the framework we conducted a within-subjects user study and found the framework to effectively increase user awareness of requested permissions

    Biological characteristics of Cadra cautella (Lep.: Pyralidae) on different varieties of stored date palm fruit of Iran

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    The postharvest pests, including the dried fruit moth Cadra cautella Walker, are important limiting factors in the exportation of dates. The biology of C. cautella, its survivorship, developmental time, fecundity, oviposition, post oviposition period, as well as longevity of the adults were studied on four date palm varieties of Zahedi, Piarom, Rabbi, and Deyri under laboratory conditions in Iran. The experiments were carried out at constant temperature room (29 ± 1 °C, 60 ± 5% RH and photoperiod 16L: 8D hrs.). The highest survivorship of egg and larval stages was recorded 92.66%, 85.89% on Zahedi and 100% for pupal stage on Rabbi. The shortest larval period was 32.93 ± 1.41 days and 33.37 ± 1.87 days on Deyri and Zahedi respectively. The shortest total development time for males from egg to adult was 40.91 ± 1.15 days and 40.97 ± 1.59 days on Zahedi and Deyri respectively and for females was 43.76 ± 2.47 days on Deyri. The longest total development time for males was 47.61 ± 1.50 days on Piarom and for female was 55.88 ± 2.31 and 55.37 ± 3.87 days on Piarom and Rabbi respectively. The highest (247.00 ± 8.53 eggs per female) and lowest (147.40 ± 12.06 eggs per female) fecundity occurred on Zahedi and Piarom, respectively. The date palm varieties Zahedi, Deyri, Rabbi and Piarom are found to be on preferrence order for C. cautella. The results of this study would be useful for planning pest management strategies in date palm fruit storages

    Phylogenic analysis of serotype Asia1 foot-and-mouth disease virus from Sulaimani/Iraq using VP1 protein: heterogeneity with vaccine strain As1/Shamir/89

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    Foot-and-mouth disease virus (FMDV) serotypes O, A and Asia1 are responsible for a significant number of disease outbreaks in Iraq. The current study can be considered as the first molecular characterization of serotype Asia1 in Iraq. The present investigation reports the detection of serotype FMDV Asia1 from local farms in Sulaimani districts in 2012 and 2014 outbreaks. Phylogenetic analysis of the complete VP1 gene has shown that FMDV Asia1 field isolates were under genetic novel variant Sindh-08 (group VII) including PAK/iso/11 and TUR/13 strains. The VP1 protein sequence of circulatory FMDV Asia1 genotype showed heterogeneity of nine amino acid substitutions within the G-H loop with the vaccine strain As1/Shamir/89 (JF739177) that is currently used in vaccination program in Iraq. Our result indicated that differences in VP1 protein at G-H loop of the locally circulated FMDV serotype Asia1 strain may be a reason for current vaccination failure

    Molecular Typing of Canine Parvovirus from Sulaimani, Iraq and Phylogenetic Analysis Using Partial Vp2 Gene

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    Canine parvovirus (CPV) remains the most significant viral cause of haemorrhagic enteritis and bloody diarrhoea in puppies over the age of 12 weeks. The objective of the present study was to detect and genotype CPV-2 by polymerase chain reaction (PCR) and to perform phylogenetic analysis using partial VP2 gene sequences. We analysed eight faecal samples of unvaccinated dogs with signs of vomiting and bloody diarrhoea during the period from December 2013 to May 2014 in different locations in Sulaimani, Kurdistan, Iraq. After PCR detection, we found that all viral sequences in our study were CPV-2b variants, which differed genetically by 0.8% to 3.6% from five commercially available vaccines. Alignment between eight nucleotides of field virus sequences showed 95% to 99.5% similarity. The phylogenetic analysis for the 8 field sequences formed two distinct clusters with two sequences belonging to strains from China and Thailand and the other six - with a strain from Egypt. Molecular characterisation and CPV typing are crucial in epidemiological studies for future prevention and control of the disease

    Spatio-Temporal Pattern of Saturn's Equatorial Oscillation

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    Recent ground-based and Cassini CIRS thermal-infrared data have characterized the spatial and temporal characteristics of an equatorial oscillation in the middle atmosphere of Saturn above the 100-mbar level. The CIRS data [I] indicated a pattern of warm and cold anomalies near the equator, stacked vertically in alternating fashion. The ground-based observations s2, although not having the altitude range or vertical resolution of the CIRS observations, covered several years and indicated an oscillation cycle of approx.15 years, roughly half of Saturn's year. In Earth's middle atmosphere, both the quasi-biennial (approx.26 months) and semi-annual equatorial oscillations have been extensively observed and studied (see e.g., [3]), These exhibit a pattern of alternating warmer and cooler zonal-mean temperatures with altitude, relative to those at subtropical latitudes. Consistent with the thermal wind equation, this is also associated with an alternating pattern of westerly and easterly zonal winds. Moreover, the pattern of winds and temperatures descends with time. Momentum deposition by damped vertically propagating waves is thought to play a key role m forcing both types of oscillation, and it can plausibly account for the descent. Here we report the direct observation of this descent in Saturn's equatorial atmosphere from Cassini radio occultation soundings in 2005 and 2009. The retrieved temperatures are consistent with a descent of 0.7 x the pressure scale height. The descent rate is related to the magnitude of the wave forcing, radiative damping, and induced meridional circulations. We discuss possible implications
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