Keith Hartley, The Political Economy of Aerospace Industries: A Key Driver of Growth and International Competitiveness?

Book Revie

Effects of Additive Manufacturing Techniques on the Magnetocaloric Properties and Chemical Stability of LaFexCoySi13-x-y Alloys

Additive manufacturing (AM) is an emerging process to fabricate net shape, intricate, engineering components with minimal material waste; however, traditionally it has been largely applied to structural materials. AM of functional materials, such as magnetic materials, has received much less attention and the field is still in its infancy. To date, AM of magnetocaloric regenerators for magnetic refrigeration (an energy-efficient alternative to the conventional vapor-compression cooling technology), remains a challenge. There are several magnetic refrigerator device designs in existence today that are predicted to be highly energy-efficient, on condition that suitable working materials can be developed. This challenge in manufacturing magnetocaloric devices is unresolved, mainly due to issues related to shaping the mostly brittle magnetocaloric alloys into thin-walled channeled regenerator structures to facilitate efficient heat transfer between the solid refrigerant and the heat exchange fluid in an active magnetic regenerator (AMR) cooling device. To address this challenge, we explore the possibility of using extrusion-based additive manufacturing (AM) for 3D printing magnetocaloric structures in this work. Nominal compositions of LaFexCoySi13-x-y alloys were used for this investigation. The effects of extrusion printing on the composition were evaluated by microstructural, crystal structure, and magnetic characteristics probing. Chemical stability of precursor powders was assessed by simulating partial in-operando conditions of an Active Magnetic Regenerator (AMR) setup where heat transfer fluid (DI water) was circulated through the magnetocaloric structure with the aid of a circulating rig. 3D printed parts were immersed in a beaker setup with room temperature tap water (300ml) placed on a magnetic stirrer to simulate flow. Results were presented as comparisons of precursor powders and 3D printed scaffold in terms of composition as well as magnetic properties. X-Ray Diffractometry (XRD) data showed no changes in the composition of the 3D printed samples with similar amounts LaFeCoSi and α-Fe phases present in the structure. Immersed samples of precursor powders showed introduction of Fe3O4 oxide phases where higher compositions of oxide were seen for samples of longer immersion. Magnetometry data showed degradation of magnetocaloric response in polymer blended 3D printed structures with a ΔSmag decrease of 35% and lowered saturation magnetization (Ms). Water immersed precursor powders showed gradual degradation of ΔSmag­ for longer immersion times as well as lowered Ms with no changes in the curie temperature (Tc) among all the samples. Broadly speaking, this work demonstrated the printability of the magnetocaloric material into a functional regenerator type structure and the poor chemical stability of LaFexCoySi13-x-y alloys

Review on Seed Health Tests and Detection Methods of Seedborne Diseases

Seed is a small embryonic plant which is an efficient means of introducing plant pathogens into a new area as well as providing a means of their survival from one cropping season to another. Seed health is a well recognized factor in the modern agricultural science for desired plant population and good harvest. Seed-borne fungi are one of the most important biotic constrains in seed production worldwide. Seed health testing to detect seed-borne pathogens is an important step in the management of crop diseases. Seed health is a measure of freedom of seeds from pathogens. ISTA, ISHI and NSHS are three primary organizations that publish standardized seed health test methods. Specificity, sensitivity, speed, simplicity, cost effectiveness and reliability are main requirements for selection of seed health tests methods. PCR has many beneficial characteristics that make it highly applicable for detecting seedborne pathogens. Since seed serve as means of dispersal and survival of plant pathogens, it is critical to test its health before using it as planting material. Seed health testing and detection is a first line approach in managing seedborn diseases of plants. Keywords: Embryonic plant, Modern agricultural, PCR, Plant pathogens, Plant population, Seedborne fung

The role of surgery for peptic ulcer in eastern Ethiopia

This was a retrospective study of 90 patients operated on for peptic ulcer disease (PUD) in Karamara Hospital, Ethiopia, between 1st April 1994 and 31st March 1995. Seventy-eight patients were admitted with a preliminary diagnosis of gastric outlet obstruction secondary to PUD (86%) and 12 as intractable PUD.The diagnosis was based solely on the history and physical examination as neither barium meal fluoroscopy nor endoscopy were available. At operation a scarred duodenum and a large stomach were found in 71 patients (79%), an active ulcer without stenosis in 10, and a stenosed duodenum with mesenteric tubercles in two. In three, there were no abnormal findings.There were four patients under 20 years old and seven over 60. The  peak-age was 39 years. There were 88 males and only two females. Truncal vagotomy with gastrojejunostomy was the operation performed for 84 cases of PUD. An accurate diagnosis had been made by clinical examination in 82 out of 90 patients. Twenty-one patients (23%) suffered early postoperative complications with pneumonia as the commonest (7). The only two 'ulcer related complications' were one case of upper gastrointestinal bleeding and intractable postoperative vomiting in one patient.It is interesting that, during the twelve months surveyed, no patients presented with either bleeding or with perforation. No late complications or deaths occurred during the study period or the following three months.Keywords: peptic ulcer, Ethiopi

The Effect of Land Use Land Cover Change on Land Degradation in the Highlands of Ethiopia

Land use and land cover change through inappropriate agricultural practices and high human and livestock population pressure have led to severe land degradation in the Ethiopian highlands. This has led to further degradation such as biodiversity loss, deforestation, soil erosion and soil quality. Agricultural and economic growth in Ethiopia is constrained by the deteriorating natural resource base, especially in the highlands where 80% of the population lives. This threat stems from the depletion and degradation of the vegetation cover of the country. Loss of biodiversity is associated with land use/land cover changes that are related to a range of biophysical and socio-economic drivers. The implications of these changes suggest that the land use/cover changes have skewed to the rampant conversion of areas once covered with vegetation to cultivation without adequate use of soil and water conservation and rehabilitation practices. Understanding of the driving forces of land use and land cover change (LULC C) is essential for effective sustainable land resource management. Change in LULC can also negatively affect the potential use of an area and may ultimately lead to land degradation.  Improving the understanding of land use and land cover dynamics can help in projecting future changes in land use and land cover and to instigate more appropriate policy interventions for achieving better land management. Keywords: Deforestation, Ethiopia, land degradation, land use, soil quality

A Review on Disease Detection, Pathogen Identification and Population Genetics in Fungi

Based on knowing the fungi how much they are important in causing holistic impacts on human welfare, the present review initiated with reviewing the different disease detection and pathogen identification methods of plant pathogenic fungi and over viewing the population genetics of fungi. Currently, more and more diagnostic laboratories and inspection agencies are using molecular methods for detection and identification of diseases caused by plant pathogenic fungi. Better understanding of fungal-plant interactions, pathogenicity factors, rapid and accurate detection of fungal pathogens to species or strain level are a crucial prerequisite for disease surveillance and development of novel disease control strategies. Molecular technology increases understanding of the biology and population structures of plant pathogens, provides quick and accurate answers to epidemiological questions about plant diseases, and supports disease management decisions. Both domestic and international plant quarantine stations must be facilitated with high throughput, rapid and sensitive methods for detection of quarantine pathogens. The methods of population genetics offer powerful tools to elucidate the life histories of important plant pathogens and address fundamental questions about the biology of these organisms. Increased knowledge of the population biology of pathogens is likely to lead to better management of disease in agricultural ecosystems. Eventhough every pathogen detection methods starting from conventional up-to the most sophisticated real-time PCR, they have their own advantages and drawbacks, but selecting of the most appropriate one based on its multi-dimensional importance is crucial at this time. In Ethiopia, most of the detection methods are based on the conventional one, but these methods are not as effective as molecular detection methods. So developing and utilizing these more effective, time sever and easy assays of fungal disease detection and pathogen identification methods is important. Keywords: Agricultural Ecosystems, Fungal-Plant Interactions, PCR, Pathogenicity Factors, Real-Time PC

The Mediating Effect of Employee Engagement Between Transformational Leadership and Job Performance in the Commercial Bank of Ethiopia

Nowadays service giving organizations are facing various challenges as a result of the competitive business environment and its dynamic nature. Service quality can be influenced by various factors such as employees’ job performance, leadership style and employee engagement which ultimately affect organizational performance as well. This paper examined the relationship between transformational leadership, employee engagement and job performance. Furthermore, the mediating effect of employee engagement between transformational leadership and job performance is examined. Questionnaires were used to collect the required data. The collected data were sorted and analyzed using statistical software called SPSS version 20.  Statistical results of descriptive statistics, correlation, simple and multiple regressions were computed and analyzed. The result supported partial mediation of employee engagement between transformational leadership and job performance. Keywords: Transformational leadership, employee engagement, job performance, mediating effect DOI: 10.7176/EJBM/11-25-04 Publication date:September 30th 201

Behavioral and fMRI-based Characterization of Cognitive Processes Supporting Learning and Retrieval of Memory for Words in Young Adults

A novel word is rarely defined explicitly during the first encounter. With repeated exposure, a decontextualized meaning of the word is integrated into semantic memory. With the overarching goal of characterizing the functional neuroanatomy of semantic processing in young adults, we employed a contextual word learning paradigm, creating novel synonyms for common animal/artifact nouns that, along with additional real words, served as stimuli for the lexical-decision based functional MRI (fMRI) experiment. Young adults (n=28) were given two types of word learning training administered in multiple sessions spread out over three days. The first type of training provided perceptual form-only training to pseudoword (PW) stimuli using a PW-detection task. The second type of training assigned the meaning of common artifacts and animals to PWs using multiple sentences to allow contextual meaning acquisition, essentially creating novel synonyms. The underlying goals were twofold: 1) to test, using a behavioral semantic priming paradigm, the hypothesis that novel words acquired in adulthood get integrated into existing semantic networks (discussed in Chapter 2); and 2) to investigate the functional neuroanatomy of semantic processing in young adults, at the single word level, using the newly learned as well as previously known word stimuli as a conduit (discussed in Chapter 3). As outlined in Chapter 2, in addition to the semantic priming test mentioned above, two additional behavioral tests were administered to assess word learning success. The first was a semantic memory test using a two-alternative sentence completion task. Participants demonstrated robust accuracy (~87%) in choosing the appropriate meaning-trained item to complete a novel sentence. Second, an old/new item recognition test was administered using both meaning and form trained stimuli (old) as well as novel foil PWs (new). Participants demonstrated: a) high discriminability between trained and novel PW stimuli. (d-prime=2.72); and b)faster reaction times and higher accuracy for meaning-trained items relative to perceptually-trained items, consistent with prior level-of-processing research. The results from the recognition and semantic memory tests confirmed that subjects could explicitly recognize trained items as well as demonstrate knowledge of the newly acquired synonymous meanings. Finally, using a lexical decision task, a semantic priming test assessed semantic integration using the novel trained items as primes for word targets that had no prior episodic association to the primes. Relative to perceptually trained primes, meaning-trained primes significantly facilitated lexical decision latencies for synonymous word targets. Taken together, the behavioral findings outlined above demonstrate that a contextual approach is effective in facilitating word learning in young adults. Words learned over a few experimental sessions were successfully retained in declarative memory, as demonstrated by behavioral performance in the semantic memory and recognition memory experiments. In addition, relative to perceptually-trained PWs, the newly meaning-trained PWs, when used as primes in a semantic priming test, facilitated lexical decisions for synonymous real words, with which the primes had no prior episodic association. The latter finding confirms our primary behavioral hypothesis that novel words acquired in adulthood are represented similarly, i.e. integrated in the same semantic memory representational network, as common words likely acquired early in the lifetime. Chapter 3 outlines the findings from the fMRI experiment used to investigate the functional neuroanatomy of semantic processing using the newly learned as well as previously known words as stimuli in a lexical decision task. fMRI data were collected using a widely-spaced event-related design, allowing isolation of item-level hemodynamic responses. Two fMRI sessions were administered separated by 2-3 days, the 1st session conducted prior to, and the 2nd session following word-learning training. Using the same items as stimuli in the fMRI sessions conducted before and after behavioral training, facilitated a within-item analysis where each item effectively served as its own control. A set of stringent criteria, outlined below, were established a-priori describing characteristics expected from regions with a role in retrieving/processing meanings at the single word level. We expected a putative semantic processing region to exhibit: a) higher BOLD activity during the 1st fMRI session for real words relative to novel PWs; b) reduced BOLD activity for repeated real words presented in the 2nd fMRI session relative to levels seen in the 1st fMRI session; c) higher BOLD activity for meaning-trained PWs relative to novel PWs; d) higher BOLD activity for meaning-trained PWs relative to perceptually-trained PWs, e) higher BOLD activity for correctly identified meaning-trained PWs (hits) relative to their incorrect counterparts (misses). Given their previously documented associations with semantic processing, we expected to identify regions in left middle temporal gyrus (MTG) and left ventral inferior frontal gyrus (vIFG) to exhibit timecourses consistent with most of the semantic criteria outlined above. Individual ANOVA contrasts, essentially targeting each of the criteria outlined above, were conducted at the voxelwise level. A fixed effects analysis based on 4 correct trial ANOVA contrasts (corresponding to criteria a-d, above) generated 81 regions of interest; and two individual error vs. correct trial ANOVA contrasts generated an additional 16 regions, for a total of 97 study-driven regions. Using region-level ANOVAs and qualitative timecourse examinations, the regions were probed for the presence of the effects outlined in the above criteria. To ensure a comprehensive analysis, additional regions were garnered from prior studies that have used a variety of tasks to target semantic processing. The literature-derived regions were subjected to similar ANOVAs and qualitative timecourse analysis as was conducted on the study-driven regions to examine if the regions exhibited effects outlined in the above criteria. The above analysis resulted in three principal observations. First, we identified regions in the left parahippocamal gyrus (PHG) and left medial superior frontal cortex (mSFC) that, by satisfying essentially all the above criteria, demonstrated a role in semantic memory retrieval for recently acquired and previously known words. Second, despite strong expectations, regions in the left MTG and left vIFG failed to show activity in support of a role in semantic retrieval for the novel words. On the contrary, the profiles seen in the two said regions, namely a ‘word \u3e novel PW’ and a word repetition suppression effect, were consistent with a role in semantic retrieval exclusively for the previously known words. The latter observation suggests that the novel words have yet to undergo adequate consolidation to engage, in addition to PHG and mSFC, canonical semantic regions such as left MTG. Third, despite the potentially crucial distinctions noted in Chapter 3, left lateral/medial parietal regions implicated in episodic memory retrieval exhibited many similar properties as those outlined for PHG and mSFC above during retrieval of newly learned words. Crucially, instead of exhibiting repetition suppression for real words, as observed in PHG/mSFC, the parietal regions showed the opposite effect resembling the episodic ‘old\u3enew’ retrieval success effect. The latter observation argues against a sematic role and in support of an episodic role consistent with previous literature. Taken together, these observations suggest that in addition to the role played by PHG/mSFC supporting semantic memory retrieval for the novel words, the parietal regions are also making significant contributions for memory retrieval of the novel words via complementary episodic processes. Finally, using item-level timecourses derived from the 97 study-driven ROI, clustering algorithms were used to group regions with similar characteristics, with the goal of identifying a cluster corresponding to a putative semantic brain system. A number of clusters were identified containing regions with anatomical and functional correspondence to previously well-characterized systems. For instance, a cluster containing regions in left lateral parietal cortex, precuneus, and superior frontal cortex corresponding to a previously described episodic memory retrieval system (Nelson et al., 2010) was identified. Two additional clusters, corresponding to frontoparietal and cinguloopercular task control systems (Dosenbach et al., 2006, 2007) were also among the identified clusters. However, the clustering analysis did not identify a cluster of regions with semantic properties, such as PHG and mSFC noted above, that could potentially correspond with a semantic brain system. The above outlined findings from the current study, juxtaposed with prior findings from the literature, were interpreted in the following manner. The two regions identified in the current study, i.e. left parahippocampal gyrus and medial superior frontal gyrus, constitute regions that are used for learning new words, and are also recruited during semantic retrieval of previously well-established meanings. In addition, the current results also suggest complementary episodic contributions to the word learning process from regions in left parietal/superior frontal cortex. The latter observation may imply strong episodic contributions to the observed behavioral semantic priming effects. A potential counter argument, i.e. in support of a semantic basis for the priming effects, is the shared recruitment, in a manner consistent with semantics, of PHG/mSFC by both novel and real word stimuli. The left middle temporal gyrus, a region that the task-evoked and neuropsychological literature consistently associates with word-level semantic processing, was not recruited during memory retrieval of novel words, despite robust engagement by previously known word stimuli. Given their association with category-selective semantic deficits, as well as their role in conceptual/perceptual processing in healthy brains, the memory consolidation literature proposes regions in the lateral temporal lobes as potential neocortical loci for consolidated long-term memory. In the current setting, it is likely the case that the novel words have yet to be adequately consolidated to engage left MTG as did the previously known words. Finally, the left vIFG exhibited similar characteristics as the left middle temporal gyrus, in that it was not recruited by the newly meaning trained stimuli, despite showing engagement by previously known words. Given that the region failed to appear in our primary contrasts, even those targeting real word stimuli, and its absence in other prior studies that have used similar lexical decision tasks as the current study, we have a slightly different interpretation for that region. The left vIFG is typically recruited in task settings that require controlled/strategic meaning retrieval, a process that may not be critical for adequate performance of the lexical decision task as employed in the current study. Taken together, these findings suggest that a relatively small amount of word learning training is sufficient to create novel words that, in young adults, behaviorally resemble the semantic characteristics of well-known words. On the other hand, the fMRI findings, particularly the failure of the newly meaning-trained items to engage regions that are canonically responsive to single word meanings (e.g. middle temporal gyrus), may suggest a more protracted timecourse for the functional signature of novel words to resemble that of well-known words. That said, the fMRI findings identified brain regions (left PHG/mSFC) that, consistent with the memory consolidation literature, serve as the functional neuroanatomical “bridge” that connects the novel words to the eventual functional representational destination

A Review Paper on Potato Virus Y (PVY) Biology, Economic Importance and its Managements

PVY is distributed worldwide in potato growing areas, tobacco growing areas and outdoor crops of tomato and pepper in warm countries. The different strains of PVY develops different symptoms on different parts of the host plant species. The PVY have a host range of  495 species in 72 genera of 31 families. Potato isolates have historically been divided into three main strain groups. The different strains of PVY have different stability under thermal inactivation point, dilution end-point and longevity in vitro. PVY have ssRNA nucleotide and two proteins (VPg and coat protein). The genomic RNA of PVY is positive sense and approximately 9700 kb in length excluding the poly(A) tail. PVY is spread from plant to plant either by aphids, mechanical means or by contact. In the family Aphidinae, Myzus persicae is clearly the most important vector of PVY given that it is widespread and with high transmission efficiency. Potato  virus  Y  belongs  to  a  group  of  the  most  important  potato  viruses  infecting  the  potato, tobacco, pepper and tomato. PVY is the most important viral pathogen in potato worldwide and can cause yield loss of 10-100% and 39-75% on tobacco. The two main types of resistance in potato are extreme  resistance  and hyper-sensitive resistance. The generation  of  resistant  cultivars  is  considered  the most  economic  and  environmentally  acceptable  way  of  controlling  viral  diseases  in  potato. Vector control plays an important role in management of PVY. Controlling the aphid plays a great role in the management of Potato virus Y. Since PVY is among the most important viral diseases of potato and that cause significant yield loss, so understanding its biology and developing an efficient management strategy is very important.  In the real world there is no singly effective management of several important diseases, on behalf of this, searching a good integrated management approach is very crucial. Keywords: Coat Protein; Hyper-sensitive Resistance; Myzus persicae; Potato; ssRNA; Vector control

The Role of Forest and Soil Carbon Sequestrations on Climate Change Mitigation

The emission of CO2 concentration from industries, burning of fossil fuels and deforestation causes GHGs. Hence, forests in terms of agroforestry, plantation, reforestation has been suggested as one of the most appropriate land management systems for mitigating atmospheric CO2 through photosynthesis process. Forest ecosystems also contribute to store more than 80% of all terrestrial aboveground C and more than 70% of all SOC. Forests operate both as vehicles for capturing additional carbon and as carbon reservoirs in different carbon pools (above ground, root and litter). The other form of carbon pool is soil carbon sequestration also increases SOC stocks through judicious land use and recommended management practices. Forest soils are one of the major carbon sinks on earth, because of their higher organic matter content. Furthermore, soil carbon sequestration is a bridge across three global issues climate change, desertification, and biodiversity. Therefore, developed countries can implement their emission reductions at lower costs and developing countries receive more capital for environmentally sound investments that contribute to sustainable development. This offers an economic opportunity for subsistence farmers in developing countries, the major practitioners of agroforestry, afforestation and reforestation for selling of carbon sequestered to industrialized countries and it will be an environmental benefit to the global community at large as well. Keywords: forest carbon sequestration, soil organic carbon, climate chang