4,102 research outputs found
The use of genetic algorithms to maximize the performance of a partially lined screened room
This paper shows that it is possible to use genetic algorithms to optimize the layout of ferrite tile absorber in a partially lined screened enclosure to produce a "best" performance. The enclosure and absorber are modeled using TLM modeling techniques and the performance is determined by comparison with theoretical normalized site attenuation of free space. The results show that it is possible to cover just 80% of the surface of the enclosure with ferrite absorber and obtain a response which is within +/-4 dB of the free space response between 40 and 200 MHz
Politicians, Narcos, Missing Students, and Mexico’s Crisis (SWP 47)
Taking the September 2014 disappearance of 43 students from the Ayotzinapa Normal School in rural Guerrero State as its point of departure, this paper explores the interlinking experiences of government corruption, narco-trafficking, and elite privilege as they have played out through the larger social crisis that followed the disappearances. I argue that the fissures within Mexican responses to Ayotzinapa reveal a great deal about the ways that racial and class privilege continue to characterize civil-society movements in Mexico. Broad, civil-society coalitions to combat political corruption, impunity and violence have been difficult to sustain here, a problem that has been particularly striking given the spectacular nature of the recent waves of violence in Mexico. This paper argues that it is the entrenched nature of middle-class and elite dependence on class and racial privilege that ultimately makes those alliances unthinkable
Vagus nerve stimulation paired with tactile training improved sensory function in a chronic stroke patient
Background: Recent studies indicate that vagus nerve stimulation (VNS) paired with rehabilitation can enhance neural plasticity in the primary sensory and motor cortices, improve forelimb function after stroke in animal models and improve motor function in patients with arm weakness after stroke. OBJECTIVE:To gain “first-in-man” experience of VNS paired with tactile training in a patient with severe sensory impairment after stroke. Methods: During the long-term follow-up phase of a clinical trial of VNS paired with motor rehabilitation, a 71-year-old man who had made good motor recovery had ongoing severe sensory loss in his left hand and arm. He received VNS paired with tactile therapy in an attempt to improve his sensory function. During twenty 2-hour sessions, each passive and active tactile event was paired with a 0.5 second burst of 0.8 mA VNS. Sensory function was measured before, halfway through, and after this therapy. Results: The patient did not report any side effects during or following VNS+Tactile therapy. Quantitative measures revealed lasting and clinically meaningful improvements in tactile threshold, proprioception, and stereognosis. After VNS+Tactile therapy, the patient was able to detect tactile stimulation to his affected hand that was eight times less intense, identify the joint position of his fingers in the affected hand three times more often, and identify everyday objects using his affected hand seven times more often, compared to baseline. Conclusions: Sensory function significantly improved in this man following VNS paired with tactile stimulation. This approach merits further study in controlled clinical trials
Origins of Religion: A Comparison between the United States and Germany
This research paper discusses the origins of religion in the nations of the United States and the Federal Republic of Germany. For the United States, the first religions were those of the European settlers. They brought with them Christianity, both Catholicism and Protestantism, as well as Judaism. Then, as immigration ramped up in the 19th and 20th centuries, many more religions arrived to America, such as Islam, Buddhism, Hinduism, as well as many more Christian followers. These immigrants came mostly from China, Africa, the Middle East, and southern and eastern Europe. As for Germany, a significantly older nation than the US, the origins of its religions can be traced back much farther. Germany can trace its religious origins back to the ancient Germanic religions which are largely based on the Norse religions, with Odin being the “God of gods”. Then, as the Romans moved further into today’s Europe, their religion began to gain Roman influence. As the Roman Empire adopted Christianity, so too would Germany. The split of Christianity at the hands of Martin Luther brought Protestantism to Germany. Then as immigration became a widespread phenomenon, so too would other religions such as Islam, Buddhism, and Hinduism. Comparing the two nations using statistical data shows that the contemporary United States seems to be more religious than the Federal Republic of Germany. However, this paper also argues that the two nations may find themselves more equal with the apparent growing trend of atheism or irreligion in general
MakuSafe Wearable Device Testing
MakuSafe Corporation needs data collected on the strength and comfortability of the holster for their wearable safety device
Carbon catalysed hydrogen exchange in petroleum source rocks
Exchange of carbon bound hydrogen has been observed when alkenes, saturated and aromatic hydrocarbons are heated at moderate temperatures on carbonaceous surfaces (activated carbon and coal). Isomerisation of alkenes and the formation of hydrogenated/dehydrogenated products from the saturated and aromatic reactants resulted. A suite of crude oils from the Carnarvon Basin (Western Australia) have been analysed with a view to comparing their relative abundances of structurally similar hydrocarbons. The consistent relationships between hydrocarbons in crude oils that are chemically related via hydrogenation/dehydrogenation reactions suggest that a hydrogen exchange process similar to that demonstrated in laboratory experiments occurs during crude oil formation in sedimentary rocks
miRNA-140-5p: new avenue for pulmonary arterial hypertension drug development?
Pulmonary arterial hypertension (PAH) is a rare but fatal disease. Pathologically, PAH is characterised by sustained vasoconstriction and progressive obliteration of small pulmonary arteries through a process of medial thickening, intimal fibrosis and the formation of angioproliferative lesions. Current treatments target the sustained vasoconstriction via either the prostacyclin, endothelin or nitric oxide pathway but do little to address the underlying progressive proliferative vascular disease. Dysregulated expression of microRNA (miR) has been identified in PAH and we have recently highlighted reduced miR-140-5p in patients with PAH. Replacement of miR-140-5p attenuated disease in animal models with the regulation of Smurf1, a E3 ubiquitin ligase targeting BMPR2 as one identified mechanism. These data highlight Smurf1 inhibition as a treatment for PAH
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Neurotoxic Effects of Low-level Organophosphate Exposure in <i>C. elegans</i> and UK Agricultural Workers
Exposure to organophosphate (OPs), pesticides, has been associated with poor mental health among agricultural workers. Although the impacts of acute exposure, such as poisoning due to AChE inhibition and cholinergic hyperexcitation, are well known, the mechanisms by which low-level exposure may impact mental health are not fully understood. Such investigations are complicated by confounding variables like physical health, life stress, and lifestyle factors.This thesis sought to bridge this gap using an interdisciplinary approach, focusing on both the biological effects of low-level OP exposure, and its impact on human wellbeing. A model was developed using the invertebrate C. elegans to examine effects at a molecular level. Results demonstrated that exposure below the threshold for significant AChE inhibition led to behavioural changes in C. elegans linked to ACE-2 acetylcholinesterase and GAR-3 muscarinic receptor, suggesting that the cholinergic system mediates some effects of low-level OP exposure, even at very low-levels.In addition, a survey among UK agricultural workers was conducted to understand the factors affecting mental health in OP-exposed populations. Data suggested that although depression symptoms were higher among agricultural workers compared to a control group of construction workers, lifestyle factors and stress appeared to be more important contributors to poor mental health than pesticide exposure.In conclusion, the research provides evidence for potential neurotoxic effects of low-level OP exposure from the C. elegans model. However, its implication in human mental health is more nuanced, with stress and lifestyle factors playing significant roles, highlighting the complexity of real-world interactions between chemical exposure and human health
Atomistic simulation of electroceramics
This work presents a range of atomistic techniques used to study the energetic and structural properties of the perovskite, barium titanate (BaTiO3). Particular attention is given to defective structures of BaTiO3 and their importance at the atomic scale and for the behaviour of the material. Using a newly developed potential model calibrated against ab initio calculations, simulations of rare earth (RE) and transition metal doping of both the cubic (space group Pm3m) and hexagonal polymorphs (space group P63/mmc) of BaTiO3 have been completed. All major dopant charge compensation schemes have been considered as well as the contribution from binding between charged defects. The results agree with simple ion size arguments and excellent agreement with experiment is observed. Clear evidence of the stabilisation of the hexagonal polymorph as a result of trivalent and tetravalent transition metal doping is presented. Lattice statics have also been used to study the energetics and structures of a range of ATiO3 solid solutions, where A is Ba, Ca and Sr. Energy of mixing curves have been produced using both the new and old potential models. The relationship between strain and the ferroelectric Curie temperature (Tc) in Ba1-xCaxTiO3 has also been considered. Molecular dynamics methods have been applied to investigate oxygen diffusion in cubic BaTiO3 and SrTiO3. Mean square displacement (MSD) calculations were completed over a range of oxygen vacancy concentrations. Diffusion coefficients and activation energies have been calculated and compared with experiment. Finally, we have performed density functional theory (DFT) simulations on mono- and di-vacancies in hexagonal BaTiO3. Defect formation energies are derived for multiple charge states and due consideration is given to the errors usually associated with such calculations. Equilibrium concentrations of vacancies in the system are also presented. Comparisons are drawn with the cubic polymorph as well as with potential-based simulations and experimental results.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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