270 research outputs found

    Effects of shoreline erosion on infrastructure development along the coastal belt of Ghana: Case of Nkontompo community

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    The coastal areas of Ghana are the locus of rapid urban and industrial growth, oil and gas development, industrial-scale fisheries, recreation and tourism destinations. However, lateral changes in the coastline position has seriously threatened the equilibrium of the coastal environment and affected the socio-economic life of local populations, threatened cultural heritage and hindered coastal tourism development. This paper assessed the extent of shoreline recession and its effects on buildings and  infrastructure along Ghana's coastline through a study of the NkontompoCommunity, a suburb of Sekondi in the Western Region of the country as a case. The study employed data spanning a period of 23 years, including Topographic sheets that were interpolated to establish the rate of recession of the shoreline. The extent of land lost in conjunction with the building density was used to establish the number of buildings lost. The study  revealed that environmental conditions at Nkontompo have changed over the past three to four decades as a result of shoreline erosion. The coastline of the community has been receding at a rate of approximately 2 metres per annum. From the topographical sheet interpolations and analysis made by the authors, it was realized that approximately nine acres of the land, forming a third of the total built up area has been eroded leading to damage and subsequent loss of about 117 buildings to the sea. Recommendations have been made identifying adaptation  techniques and strategies to manage the effects of this phenomenon along the coastal belt of Ghana.Keywords: Coastal erosion, infrastructure development, Nkontompo, Ghan

    Investigating neuromagnetic brain responses against chromatic flickering stimuli by wavelet entropies

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    BACKGROUND: Photosensitive epilepsy is a type of reflexive epilepsy triggered by various visual stimuli including colourful ones. Despite the ubiquitous presence of colorful displays, brain responses against different colour combinations are not properly studied. METHODOLOGY/PRINCIPAL FINDINGS: Here, we studied the photosensitivity of the human brain against three types of chromatic flickering stimuli by recording neuromagnetic brain responses (magnetoencephalogram, MEG) from nine adult controls, an unmedicated patient, a medicated patient, and two controls age-matched with patients. Dynamical complexities of MEG signals were investigated by a family of wavelet entropies. Wavelet entropy is a newly proposed measure to characterize large scale brain responses, which quantifies the degree of order/disorder associated with a multi-frequency signal response. In particular, we found that as compared to the unmedicated patient, controls showed significantly larger wavelet entropy values. We also found that Renyi entropy is the most powerful feature for the participant classification. Finally, we also demonstrated the effect of combinational chromatic sensitivity on the underlying order/disorder in MEG signals. CONCLUSIONS/SIGNIFICANCE: Our results suggest that when perturbed by potentially epileptic-triggering stimulus, healthy human brain manages to maintain a non-deterministic, possibly nonlinear state, with high degree of disorder, but an epileptic brain represents a highly ordered state which making it prone to hyper-excitation. Further, certain colour combination was found to be more threatening than other combinations

    Cerebrovascular reactivity among native-raised high altitude residents: an fMRI study

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    Background: The impact of long term residence on high altitude (HA) on human brain has raised concern among researchers in recent years. This study investigated the cerebrovascular reactivity among native-born high altitude (HA) residents as compared to native sea level (SL) residents. The two groups were matched on the ancestral line, ages, gender ratios, and education levels. A visual cue guided maximum inspiration task with brief breath holding was performed by all the subjects while Blood-Oxygenation-Level-Dependent (BOLD) functional Magnetic Resonance Imaging (fMRI) data were acquired from them

    The State Relationship with Religion:defined through disciplinary procedures of accounting and regulation

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    State regulation of charities is increasing. Nevertheless, although religious entities also pursue charitable objectives, jurisdictions often regulate them differently. In some states (including England until recently), the church (religious charities) are not called to account for their common-good contribution, despite owning significant assets and receiving public and government income. These regulatory and accounting variations emanate from a state’s historically informed positional relationship with religion, which may be discordant against increasing religious pluralism and citizens’ commonly-held beliefs. To open a debate on state–church relationships within the accounting history literature, this article analyses changes in England since 1534. It utilises a state–church framework from Monsma and Soper, combined with an application and extension of Foucauldian governmentality. The longitudinal study shows direct and indirect governmentality tools change with the state–church relationship. Such harmonisation of regulatory approach relies on citizens/entities subverting imposition of state demands which fail to meet their concept of common-good

    Polaron pair mediated triplet generation in polymer/fullerene blends

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    Electron spin is a key consideration for the function of organic semiconductors in light-emitting diodes and solar cells, as well as spintronic applications relying on organic magnetoresistance. A mechanism for triplet excited state generation in such systems is by recombination of electron-hole pairs. However, the exact charge recombination mechanism, whether geminate or nongeminate and whether it involves spin-state mixing is not well understood. In this work, the dynamics of free charge separation competing with recombination to polymer triplet states is studied in two closely related polymer-fullerene blends with differing polymer fluorination and photovoltaic performance. Using time-resolved laser spectroscopic techniques and quantum chemical calculations, we show that lower charge separation in the fluorinated system is associated with the formation of bound electron-hole pairs, which undergo spin-state mixing on the nanosecond timescale and subsequent geminate recombination to triplet excitons. We find that these bound electron-hole pairs can be dissociated by electric fields

    Modelling low velocity impact induced damage in composite laminates

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    The paper presents recent progress on modelling low velocity impact induced damage in fibre reinforced composite laminates. It is important to understand the mechanisms of barely visible impact damage (BVID) and how it affects structural performance. To reduce labour intensive testing, the development of finite element (FE) techniques for simulating impact damage becomes essential and recent effort by the composites research community is reviewed in this work. The FE predicted damage initiation and propagation can be validated by Non Destructive Techniques (NDT) that gives confidence to the developed numerical damage models. A reliable damage simulation can assist the design process to optimise laminate configurations, reduce weight and improve performance of components and structures used in aircraft construction

    Where Nothing Happened: The Experience of War Captivity and Levinas’s Concept of the ‘There Is’

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    This article takes as its subject matter the juridico-political space of the prisoner of war (POW) camp. It sets out to determine the nature of this space by looking at the experience of war captivity by Jewish members of the Western forces in World War II, focusing on the experience of Emmanuel Levinas, who spent 5 years in German war captivity. On the basis of a historical analysis of the conditions in which Levinas spent his time in captivity, it argues that the POW camp was a space of indifference that was determined by the legal exclusion of prisoners from both war and persecution. Held behind the stage of world events, prisoners were neither able to exercise their legal agency nor released from law into a realm of extra-legal violence. Through a close reading of Levinas’s early concept of the ‘there is’ [il y a], the article seeks to establish the impact on prisoners of prolonged confinement in such a space. It sets out how prisoners’ subjectivity dissolved in the absence of meaningful relations with others and identifies the POW camp as a space in which existence was reduced to indeterminate, impersonal being

    Modelling low velocity impact induced damage in composite laminates

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    The paper presents recent progress on modelling low velocity impact induced damage in fibre reinforced composite laminates. It is important to understand the mechanisms of barely visible impact damage (BVID) and how it affects structural performance. To reduce labour intensive testing, the development of finite element (FE) techniques for simulating impact damage becomes essential and recent effort by the composites research community is reviewed in this work. The FE predicted damage initiation and propagation can be validated by Non Destructive Techniques (NDT) that gives confidence to the developed numerical damage models. A reliable damage simulation can assist the design process to optimise laminate configurations, reduce weight and improve performance of components and structures used in aircraft construction

    The insect pathogenic bacterium Xenorhabdus innexi has attenuated virulence in multiple insect model hosts yet encodes a potent mosquitocidal toxin

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