37 research outputs found

    Detecting shielded explosives by coupling prompt gamma neutron activation analysis and deep neural networks

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    Prompt Gamma Neutron Activation Analysis is a nuclear-based technique that can be used in explosives detection. It relies on bombarding unknown samples with neutrons emitted from a neutron source. These neutrons interact with the sample nuclei emitting the gamma spectrum with peaks at specific energies, which are considered a fingerprint for the sample composition. Analyzing these peaks heights will give information about the unknown sample material composition. Shielding the sample from gamma rays or neutrons will affect the gamma spectrum obtained to be analyzed, providing a false indication about the sample constituents, especially when the shield is unknown. Here we show how using deep neural networks can solve the shielding drawback associated with the prompt gamma neutron activation analysis technique in explosives detection. We found that the introduced end-to-end framework was capable of differentiating between explosive and non-explosive hydrocarbons with accuracy of 95% for the previously included explosives in the model development data set. It was also, capable of generalizing with accuracy 80% over the explosives which were not included in the model development data set. Our results show that coupling prompt gamma neutron activation analysis with deep neural networks has a good potential for high accuracy explosives detection regardless of the shield presence

    The family Conopidae (Diptera) in Egypt and Saudi Arabia

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    The present study is one in a series of planned studies aiming to catalogue the whole order Diptera in both Egypt and Saudi Arabia.All known Egyptian and Saudi Arabian conopid taxa are systematically catalogued in the present study. Three species recorded herein for the first time from Saudi Arabia: Conops (Asiconops) elegans Meigen, 1804 and Thecophora atra (Fabricius, 1775) (Al-Baha region, southwestern of Saudi Arabia); Conops (Conops) quadrifasciatus De Geer, 1776 (Tabuk region, northwestern of Saudi Arabia). Physocephala variegata (Meigen, 1924) is also recorded for the first time from Gebel Elba, the southeastern triangle of Egypt. Considering that Gebel Elba in Egypt and Al-Baha in Saudi Arabia are affiliated to the Afrotropical Region, this is the first time to record Physocephala variegata and Thecophora atra from the Afrotropical Region. An updated taxonomy, world and local distributions, dates of collection and some colored photographs are provided

    Effects of Climatic Change on Potential Distribution of Spogostylum ocyale (Diptera: Bombyliidae) in the Middle East Using Maxent Modelling

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    Spogostylum ocyale (Wiedemann 1828) is a large robust species of bee fly (family Bombyliidae), known to be a larval ectoparasitoid as well as an important flower pollinator as an adult. This species has become extremely rare or has disappeared from many of its historic habitats due to substantial changes in floral and faunal compositions in recent years. Climate change and urbanisation, together with other anthropogenic activities, may be to blame for these changes. Distribution modelling based on environmental variables together with known occurrences is a powerful tool in analytical biology, with applications in ecology, evolution, conservation management, epidemiology and other fields. Based on climatological and topographic data, the current and future distributions of the parasitoid in the Middle East region was predicted using the maximum entropy model (Maxent). The model performance was satisfactory (AUC mean = 0.834; TSS mean = 0.606) and revealed a good potential distribution for S. ocyale featured by the selected factors. A set of seven predictors was chosen from 19 bioclimatic variables and one topographic variable. The results show that the distribution of S. ocyale is mainly affected by the maximum temperature of the warmest period (Bio5) and temperature annual range (Bio7). According to the habitat suitability map, coastal regions with warm summers and cold winters had high to medium suitability. However, future scenarios predict a progressive decline in the extent of suitable habitats with global climate warming. These findings lead to robust conservation management measures in current or future conservation planning

    Effects of Climatic Change on Potential Distribution of <i>Spogostylum ocyale</i> (Diptera: Bombyliidae) in the Middle East Using Maxent Modelling

    No full text
    Spogostylum ocyale (Wiedemann 1828) is a large robust species of bee fly (family Bombyliidae), known to be a larval ectoparasitoid as well as an important flower pollinator as an adult. This species has become extremely rare or has disappeared from many of its historic habitats due to substantial changes in floral and faunal compositions in recent years. Climate change and urbanisation, together with other anthropogenic activities, may be to blame for these changes. Distribution modelling based on environmental variables together with known occurrences is a powerful tool in analytical biology, with applications in ecology, evolution, conservation management, epidemiology and other fields. Based on climatological and topographic data, the current and future distributions of the parasitoid in the Middle East region was predicted using the maximum entropy model (Maxent). The model performance was satisfactory (AUC mean = 0.834; TSS mean = 0.606) and revealed a good potential distribution for S. ocyale featured by the selected factors. A set of seven predictors was chosen from 19 bioclimatic variables and one topographic variable. The results show that the distribution of S. ocyale is mainly affected by the maximum temperature of the warmest period (Bio5) and temperature annual range (Bio7). According to the habitat suitability map, coastal regions with warm summers and cold winters had high to medium suitability. However, future scenarios predict a progressive decline in the extent of suitable habitats with global climate warming. These findings lead to robust conservation management measures in current or future conservation planning

    A robust decentralized observer-based stabilization method for interconnected nonlinear systems: improved LMI conditions

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    International audienceThis chapter presents a new decentralized observer-based controller design method for nonlinear discrete-time interconnected systems with nonlinear interconnections. Thanks to some algebraic transformations and the use of a new variant of Young’s inequality, an linear matrix inequality (LMI)-based approach is provided to compute the observer-based controller gain matrices. Furthermore, the congruence principle is used under a judicious and new manner to include additional slack variables and to cancel some bilinear matrix coupling. The resulting final LMI conditions are less conservative compared with the techniques existing in the literature. The effectiveness of the proposed methodology is shown through two illustrative examples

    Virus isolations and high population density implicate \u3ci\u3eCulex antennatus\u3c/i\u3e (Becker) (Diptera: Culicidae) as a vector of Rift Valley Fever virus during an outbreak in the Nile Delta of Egypt

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    In June, 2003, Egypt’s hospital-based electronic disease surveillance system began to record increased cases of acute febrile illness from governorates in the Nile Delta. In response to a request for assistance from the Egyptian Ministry of Health and the World Health Organization (WHO), the U.S. Naval Medical Research Unit No. 3 (NAMRU-3) provided assistance in identifying the cause and extent of this outbreak. Testing of human clinical samples (n = 375) from nine governorates in Egypt identified 29 cases of RVF viremia that spanned the period of June to October, and a particular focus of disease in Kafr el Sheikh governorate (7.7% RVF infection rate). Veterinary samples (n = 101) collected during this time in Kafr el Sheikh and screened by immunoassay for RVFV-specific IgM identified probable recent infections in cattle (10.4%) and sheep (5%). Entomologic investigations that focused in rural, rice growing villages in the Sidi Salim District of Kafr el Sheikh during August–September, 2003, collected, identified, and tested hostseeking female mosquitoes for the presence of pathogenic viruses. Three isolates of RVF virus (RVFV) were obtained from 297 tested pools of female mosquitoes and all three RVFV isolates came from Cx. antennatus (Becker). While Cx. pipiens has been considered the primary vector of RVF virus in Egypt and is often the most common man-biting species found, Cx. antennatus was the dominant species captured at the 2003 outbreak location in Kafr el Sheikh governorate. This is the first time that Cx. antennatus has been found naturally infected with RVFV in Egypt
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