Robust filtering for uncertain discrete-time systems with uncertain noise covariance and uncertain observations

The use of Kalman filtering is very common in state estimation problems. The problem with Kalman filters is that they require full prior knowledge about the system modeling. It is also assumed that all the observations are fully received. In real applications, the previous assumptions are not true all the time. It is hard to obtain the exact system model and the observations may be lost due to communication problems. In this paper, we consider the design of a robust Kalman filter for systems subject to uncertainties in the state and white noise covariances. The systems under consideration suffer from random interruptions in the measurements process. An upper bound for the estimation error covariance is proposed. The proposed upper bound is further minimized by selection of optimal filter parameters. Simulation example shows the effectiveness of the proposed filter.<br /

X-Ray Spectral Study of AGN Sources Content in Some Deep Extragalactic XMM-Newton Fields

We undertake a spectral study of a sample of bright X-ray sources taken from six XMM-Newton fields at high galactic latitudes, where AGN are the most populous class. These six fields were chosen such that the observation had an exposure time more than 60 ksec, had data from the EPIC-pn detector in the full-Frame mode and lying at high galactic latitude $|b| > 25^o$ . The analysis started by fitting the spectra of all sources with an absorbed power-law model, and then we fitted all the spectra with an absorbed power-law with a low energy black-body component model.The sources for which we added a black body gave an F-test probability of 0.01 or less (i.e. at 99% confidence level), were recognized as sources that display soft excess. We perform a comparative analysis of soft excess spectral parameters with respect to the underlying power-law one for sources that satisfy this criterion. Those sources, that do not show evidence for a soft excess, based on the F-test probability at a 99% confidence level, were also fitted with the absorbed power-law with a low energy black-body component model with the black-body temperature fixed at 0.1 and 0.2 keV. We establish upper limits on the soft excess flux for those sources at these two temperatures. Finally we have made use of Aladdin interactive sky atlas and matching with NASA/IPAC Extragalactic Database (NED) to identify the X-ray sources in our sample. For those sources which are identified in the NED catalogue, we make a comparative study of the soft excess phenomenon for different types of systems

Insights into seeds priming effects using a magnetic field and algal treatments on growth and productivity of faba bean under salinity stress conditions

Soil fertility and crop productivity in the Nile Delta are severely threatened by soil salinization. Hence, the development of reliable techniques to enhance the salinity tolerance of plants is an essential prerequisite for the desirable sustainable agricultural development in Egypt. In the present study, we evaluated the influence of seeds priming using a magnetic field (MF) at different exposure times (0, 15, 30, and 45 min), either alone or combined with seeds pre-soaking or foliar spraying with seaweed extracts of Hydroclathrus clathratus and Acanthophora spicifera. The effects on soil properties, growth, yield, and seed quality of Vicia faba grown in saline soil were assessed. Results indicated that MF-treated seeds (MFTS), either alone or coupled with seaweed treatments, distinctly improved soil characterization by decreasing EC and pH niches, and also increased the availability of soil macro- and micronutrient elements, particularly at MF long exposure time (≥30 min). MFTS and/or MFTS with seaweed treatments at 30 min improved soil fertility indices (CO2 evolution and nitrogenase activity) and induced the highest increases of macro- and micro-nutrient contents in seeds, plant growth and seed quality. Additionally, enhancement of chlorophyll a and b, carbohydrates and amino acids, and decreasing proline levels were the bases of salinity stress alleviation. Conclusively, seed priming in the MF coupled with foliar spraying of seaweed extracts could be a sustainable and affordable approach for cultivating V. faba plants under salinity stress conditions

EVALUATION OF GENTAMICIN INDUCED NEPHROTOXICITY IN CANINE: CLINICAL, HEMATOLOGICAL, BIOCHEMICAL, ULTRASONOGRAPHIC AND HISTOPATHOLOGICAL FINDINGS

The present study was planned to evaluate the clinical, hematological, biochemical, ultrasonographic, and histopathological alterations in kidneys and other organs in dogs injected with gentamicin. Six mongrel dogs were experimentally injected I/M with gentamicin by 20 mg/kg BW daily till the appearance of renal failure signs. Blood samples were collected before and after induction (on day 9 and day 12). Hematological results revealed a non-significant decrease in hemoglobin and RBC’s, a significant decrease in hematocrit values on both days, a non-significant increase in TLC at day 12 but a non-significant decrease at day 9, a significant increase in non-segmented neutrophil at day 9 but non-significant decrease at day 12, non-significant decrease in lymphocyte at day 9 but non-significant increase at day 12, a significant increase in monocyte at day 9 but non-significant decrease at day 12. Biochemical results revealed a significant increase in urea and creatinine on day 12 and a non-significant increase on day 9. Urinalysis results indicated an increase in leukocyte, albumin, glucose, pus cells, and RBCs. Urine culture revealed isolates of E.coli, Proteus, and Staphylococcus bacteria. Ultrasonographic results showed increased echogenicity of renal cortex with loss of corticomedullary junction on day 9. On day 12 ultrasonographic results revealed intensive hyper-echogenicity of the renal cortex, increased echogenicity of the right renal cortex as compared with the spleen, and the renal cortex of the right kidney appeared more hyperechoic when compared with the liver. Histopathological examination of kidneys showed different degenerative changes, hemorrhages, nephritis, and other organs revealed degeneration, inflammation, and hemorrhages. The findings indicated that despite the therapeutic effect of gentamicin in treating kidney infection, it may have an adverse effect on kidneys and other organs, especially with massive doses

A New Regional Cold War in the Middle East and North Africa: Regional Security Complex Theory Revisited

Since the 2003 Iraq war, the Middle East and North Africa has entered into a New Regional Cold War, characterised by two competing logics: on the one hand, the politicisation of sectarianism opposing a Saudi-led Sunni bloc against an Iran-led Shia bloc and, on the other, an intra-Sunni cleavage around the mobilisation of political Islam, embodied by the Muslim Brotherhood and its supporters vs its opponents. Blending Buzan and Weaver’s regional security complex theory with Donnelly’s notion of ‘heterarchy’ and applying it to the cold wars the region has experienced, the similarities and differences between the Arab Cold War of the 1950s/60s and the New Regional Cold War reveal the increasing number of heterarchic features within the regional security complex: multiple and heterogeneous power centres, different power rankings, a more visible and relevant role of non-state and transnational actors, and the fragmentation of regional norms

Why Do States Develop Multi-tier Emigrant Policies? Evidence from Egypt

Why do states vary their policies towards their citizens abroad, and why are some emigrant groups treated preferentially to others? The literature on the politics of international migration has yet to explore this as a separate field of inquiry, assuming that states adopt a single policy that encourages, sustains or prevents emigration abroad. Yet, in the case of Egypt, the state developed a multi-tiered policy that distinctly favoured specific communities abroad over others. I hypothesise that policy differentiation is based upon the perceived utility of the emigrant group remaining abroad versus the utility of its return. This utility is determined by two factors: the sending state’s domestic political economy priorities and its foreign policy objectives

Mode of gene action and heterosis for physiological, biochemical, and agronomic traits in some diverse rice genotypes under normal and drought conditions

Water scarcity is a crucial environmental stress that constrains rice growth and production. Thus, breeding for developing high-yielding and drought-tolerant rice genotypes is decisive in sustaining rice production and ensuring global food security, particularly under stress conditions. To this end, this study was conducted to evaluate the effects of water deficit on 31 genotypes of rice (seven lines, viz., Puebla, Hispagran, IET1444, WAB1573, Giza177, Sakha101, and Sakha105, and three testers, viz., Sakha106, Sakha107, and Sakha108) and their 21 crosses produced by line × tester mating design under normal and water deficit conditions; this was to estimate the combining ability, heterosis, and gene action for some traits of physiological, biochemical, and yield components. This study was performed during the summer seasons of 2017 and 2018. The results showed that water deficit significantly decreased relative water content, total chlorophyll content, grain yield, and several yield attributes. However, osmolyte (proline) content and antioxidant enzyme activities (CAT and APX) were significantly increased compared with the control condition. Significant mean squares were recorded for the genotypes and their partitions under control and stress conditions, except for total chlorophyll under normal irrigation. Significant differences were also detected among the lines, testers, and line × tester for all the studied traits under both irrigation conditions. The value of the σ²GCA variance was less than the value of the σ²SCA variance for all the studied traits. In addition, the dominance genetic variance (σ2D) was greater than the additive genetic variance (σ2A) in controlling the inheritance of all the studied traits under both irrigation conditions; this reveals that the non-additive gene effects played a significant role in the genetic expression of the studied traits. The two parental genotypes (Puebla and Hispagran) were identified as good combiners for most physiological and biochemical traits, earliness, shortness, grain yield, and 1,000-grains weight traits. Additionally, the cross combinations Puebla × Sakha107, Hispagran × Sakha108, and Giza177 × Sakha107 were the most promising. These results demonstrated the substantial and desirable specific combining ability effects on all the studied traits, which suggested that it could be considered for use in rice hybrid breeding programs