Spiking Neural Network Connectivity and its Potential for Temporal Sensory Processing and Variable Binding

The most biologically-inspired artificial neurons are those of the third generation, and are termed spiking neurons, as individual pulses or spikes are the means by which stimuli are communicated. In essence, a spike is a short-term change in electrical potential and is the basis of communication between biological neurons. Unlike previous generations of artificial neurons, spiking neurons operate in the temporal domain, and exploit time as a resource in their computation. In 1952, Alan Lloyd Hodgkin and Andrew Huxley produced the first model of a spiking neuron; their model describes the complex electro-chemical process that enables spikes to propagate through, and hence be communicated by, spiking neurons. Since this time, improvements in experimental procedures in neurobiology, particularly with in vivo experiments, have provided an increasingly more complex understanding of biological neurons. For example, it is now well understood that the propagation of spikes between neurons requires neurotransmitter, which is typically of limited supply. When the supply is exhausted neurons become unresponsive. The morphology of neurons, number of receptor sites, amongst many other factors, means that neurons consume the supply of neurotransmitter at different rates. This in turn produces variations over time in the responsiveness of neurons, yielding various computational capabilities. Such improvements in the understanding of the biological neuron have culminated in a wide range of different neuron models, ranging from the computationally efficient to the biologically realistic. These models enable the modelling of neural circuits found in the brain. In recent years, much of the focus in neuron modelling has moved to the study of the connectivity of spiking neural networks. Spiking neural networks provide a vehicle to understand from a computational perspective, aspects of the brain’s neural circuitry. This understanding can then be used to tackle some of the historically intractable issues with artificial neurons, such as scalability and lack of variable binding. Current knowledge of feed-forward, lateral, and recurrent connectivity of spiking neurons, and the interplay between excitatory and inhibitory neurons is beginning to shed light on these issues, by improved understanding of the temporal processing capabilities and synchronous behaviour of biological neurons. This research topic aims to amalgamate current research aimed at tackling these phenomena.

Conspicuous by their abstinence: the limited engagement of heroin users in English and Welsh Drug Recovery Wings

Background In recent years, an abstinence-focused, ‘recovery’ agenda has emerged in UK drug policy, largely in response to the perception that many opioid users had been ‘parked indefinitely’ on Opioid Substitution Therapy (OST). The introduction of ten pilot ‘Drug Recovery Wings’ (DRWs) in 2011 represents the application of this recovery agenda to prisons. This paper describes the DRWs’ operational models, the place of opiate dependent prisoners within them, and the challenges of delivering ‘recovery’ in prison. Methods In 2013, the implementation and operational models of all ten pilot DRWs were rapidly assessed. Up to three days were spent in each DRW, undertaking semi-structured interviews with a sample of 94 DRW staff and 102 DRW residents. Interviews were fully transcribed, and coded using grounded theory. Findings from the nine adult prisons are presented here. Results Four types of DRW were identified, distinguished by their size and selection criteria. Strikingly, no mid- or large-sized units regularly supported OST recipients through detoxification. Type A were large units whose residents were mostly on OST with long criminal records and few social or personal resources. Detoxification was rare, and medication reduction slow. Type B's mid-sized DRW was developed as a psychosocial support service for OST clients seeking detoxification. However, staff struggled to find such prisoners, and detoxification again proved rare. Type C DRWs focused on abstinence from all drugs, including OST. Though OST clients were not intentionally excluded, very few applied to these wings. Only Type D DRWs, offering intensive treatment on very small wings, regularly recruited OST recipients into abstinence-focused interventions. Conclusion Prison units wishing to support OST recipients in making greater progress towards abstinence may need to be small, intensive and take a stepped approach based on preparatory motivational work and extensive preparation for release. However, concerns about post-release deaths will remain.

The Marquess of Londonderry: Aristocracy, Power and Politics in Britain and Ireland

The decline and fall of the British aristocracy looked headlong and irreversible in the twentieth century yet many grandees tried to preserve their power, wealth and influence by every means - and with some success. There is no better example than the Seventh Marquess of Londonderry whose life from 1878 to 1949 spanned and mirrored the period. The Londonderrys had enjoyed immense wealth in land and minerals in Britain and Ireland for centuries, played leading roles in Parliament and the state, and in an earlier time the Seventh Marquess would have continued in the family tradition of patrician prominence. Drawing upon original state and family papers, N.C. Fleming places the Londonderrys in the context of the history and the political theory of aristocracy and shows the constant struggle - not without success - against marginalisation. The theme runs through Londonderry's career as Conservative MP, on the Irish Viceroy's Council, as a junior minister in Lloyd Geroge's coalition, at the Air Ministry with Trenchard - the 'father of the RAF' - and in the National Government. Perhaps an element of desperation entered in his private business ventures and with contacts with the far Right - all in sharp contrast to past family achievement.

University Symphonic Band, April 28, 1940

Concert program for University Symphonic Band, April 28, 1940

Symphonic Band, March 7, 1976

Concert program for Symphonic Band, March 7, 1976

Análise de falhas nas superfícies de alto desempenho para a estabilidade transversal de navios (robaletes)

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Mecânica

Norton de Matos, o improvável republicano: Um olhar sobre Portugal e o império entre Afonso Costa e Salazar

Discutir o papel político de José Norton de Matos (1867-1955) na galáxia republicana portuguesa entre 1910 e 1955 é o objectivo principal desta tese. A alteração do prisma de análise mais habitual quando se fala de Norton, do colonial para o político, foi acompanhada pela opção de privilegiar os seus escritos contemporâneos, em detrimento das muitas análises retrospectivas posteriormente publicadas, e de cotejar a sua voz com múltiplas vozes de Portugal e do império, entre muitas outras com que se cruzou. Tentámos compreender como é que um liberal como Norton, monárquico de tradição embora não de filiação, usa as suas credenciais coloniais para entrar na política republicana à boleia da polémica do cacau escravo e da Sociedade Portuguesa Anti-Esclavagista. Com a aproximação a Bernardino Machado, aos Jovens Turcos, à maçonaria e à facção do PRP dominada por Afonso Costa, insere-se na órbita democrática e afonsista e ganha o cargo de governador-geral de Angola. Aos africanos, cuja definição legislativa como uma categoria distinta da de cidadão (o indígena) antecipa em 1913, leva as luzes da educação laica e a liberdade de trabalho mas paradoxalmente convive com as escolas das missões e o trabalho forçado. A fibra de político que revela na gestão das tensões entre as elites coloniais e metropolitanas irá ser apurada como ministro da Guerra. Discutimos, em especial, o seu papel político num ambicioso projecto: transformar dezenas de milhares de portugueses, pobres, analfabetos e vindos de meios rurais com parcas simpatias republicanas, em cidadãos e soldados da República. A improvisação, que possibilitou que o Corpo Expedicionário Português fosse combater em França ao lado dos britânicos, teve o rasgo de asa e os problemas inerentes à megalomania que o caracterizava. No Verão de 1917, o prestígio com que regressa à capital após difíceis negociações com o governo de Lloyd George torna-o um sério concorrente de Afonso Costa embora com ele partilhe também o ónus da crescente impopularidade da guerra. Reencontrar-se-ão, após o exílio sidonista, na Conferência da Paz em Paris mas, ao contrário de Costa, que não regressará à política activa, Norton tornar-se-á o altocomissário mais marcante e polémico da nova República do pós-guerra. Após a queda do regime e dois novos exílios, será Norton de Matos a fazer os compromissos necessários para permanecer no país e, aí, combater a Ditadura Militar e o Estado Novo de Salazar. Quando, em 1931, consegue unir a oposição em torno da Aliança Republicano-Socialista, começa a impor-se como símbolo da I República. É com esse estatuto que integrará as frentes unidas antifascistas dos anos 40 que culminarão na sua candidatura à Presidência da República em 1948/1949. O modo como consegue fazer a ponte entre os vários ciclos e gerações da oposição e, simultaneamente, resistir às pressões para romper a unidade com os comunistas na fase mais crispada da Guerra Fria será uma última manifestação do seu talento político, cuja análise poderá ajudar a enriquecer o debate sobre essa realidade plural e multipolar que foi a galáxia republicana na primeira metade do século XX.

Blood pressure loci identified with a gene-centric array.

Raised blood pressure (BP) is a major risk factor for cardiovascular disease. Previous studies have identified 47 distinct genetic variants robustly associated with BP, but collectively these explain only a few percent of the heritability for BP phenotypes. To find additional BP loci, we used a bespoke gene-centric array to genotype an independent discovery sample of 25,118 individuals that combined hypertensive case-control and general population samples. We followed up four SNPs associated with BP at our p < 8.56 × 10(-7) study-specific significance threshold and six suggestively associated SNPs in a further 59,349 individuals. We identified and replicated a SNP at LSP1/TNNT3, a SNP at MTHFR-NPPB independent (r(2) = 0.33) of previous reports, and replicated SNPs at AGT and ATP2B1 reported previously. An analysis of combined discovery and follow-up data identified SNPs significantly associated with BP at p < 8.56 × 10(-7) at four further loci (NPR3, HFE, NOS3, and SOX6). The high number of discoveries made with modest genotyping effort can be attributed to using a large-scale yet targeted genotyping array and to the development of a weighting scheme that maximized power when meta-analyzing results from samples ascertained with extreme phenotypes, in combination with results from nonascertained or population samples. Chromatin immunoprecipitation and transcript expression data highlight potential gene regulatory mechanisms at the MTHFR and NOS3 loci. These results provide candidates for further study to help dissect mechanisms affecting BP and highlight the utility of studying SNPs and samples that are independent of those studied previously even when the sample size is smaller than that in previous studies.

New gene functions in megakaryopoiesis and platelet formation.

Platelets are the second most abundant cell type in blood and are essential for maintaining haemostasis. Their count and volume are tightly controlled within narrow physiological ranges, but there is only limited understanding of the molecular processes controlling both traits. Here we carried out a high-powered meta-analysis of genome-wide association studies (GWAS) in up to 66,867 individuals of European ancestry, followed by extensive biological and functional assessment. We identified 68 genomic loci reliably associated with platelet count and volume mapping to established and putative novel regulators of megakaryopoiesis and platelet formation. These genes show megakaryocyte-specific gene expression patterns and extensive network connectivity. Using gene silencing in Danio rerio and Drosophila melanogaster, we identified 11 of the genes as novel regulators of blood cell formation. Taken together, our findings advance understanding of novel gene functions controlling fate-determining events during megakaryopoiesis and platelet formation, providing a new example of successful translation of GWAS to function.

Tradeoff analysis for anchoveta management in Peru

Estudia el valor de la pesquería en función de los objetivos de la gestión. Busca implementar una función que combine el beneficio promedio de biomasa a largo plazo y a largo plazo promedio.

Geology of the Sand Creek porphyry molybdenum prospect /

The Sand Creek Prospect is located within the eastern exposed margin of the Coast Plutonic Complex. The occurrence is a plug and dyke porphyry molybdenum deposit. The rock types, listed in decreasing age: 1) metamorphlc schists and gneisses; 2) diorite suite rocks - diorite, quartz diorite, tonalite; 3) rocks of andesitic composition; 4) granodiorites, coarse porphyritic granodiorite, quartzfeldspar porphyry, feldspar porphyry; and 5) lamprophyre. Hydrothermal alteration is known to have resulted from emplacement of the hornblende-feldspar porphyry through to the quartz-feldspar porphyry. Molybdenum mineralization is chiefly associated with the quartz-feldspar porphyry. Ore mineralogy is dominated by pyrite with subordinate molybdenite, chalcopyrite, covelline, sphalerite, galena, scheelite, cassiterite and wolframite. Molybdenite exhibits a textural gradation outward from the quartz-feldspar porphyry. That is, disseminated rosettes and rosettes in quartz veins to fine-grained molybdenite in quartz veins and potassic altered fractures to fine-grained molybdenite paint or 6mears in the peripheral zones. The quartz-feldspar porphyry dykes were emplaced in an inhomogeneous stress field. The trend of dykes, faults and shear zones is 0^1° to 063° and dips between 58° NW and 86* SE. Joint Pole distribution reflects this fault orientation. These late deformatior maxima are probably superimposed upon annuli representing diapiric emplacement of the plutons. A model of emplacement involving two magmatic pulses is given in the following sequence: Diorite pulse (i) dioritequartz diorite, (ii) tonalites; granodiorite pulse (iii) hornblende-fildspar microporphyry, hornblende/biotite porphyry, (iv) coarse grained granodiorite, (v) quartz-feldspar porphyry, (vi) feldspar porphyry, and (vii) lamprophyre. The combination of plutonic and coarse porphyritic textures, extensive propylitic overprinting of potassic alteration assemblages suggests that the. prospect represents the lower reaches of a porphyry system.

Coriolis effects in symmetric top spectra /

The "x-y Coriolis Coupling Theory" as presented by Dilauro and Mills (1966) is reformulated and extended to the determination of Raman intensities. Theoretical Raman and Infrared spectra are computed in order to understand the effects due to this coupling in both types of spectra. Both the Infrared and Raman spectra obtained indicate very real effects due to Coriolis coupling. In some of the cases chosen the computed spectra are grossly different from the normal spectra where coupling is absent. Such large effects can greatly impede the interpretation of experimental results. Theoretical spectra therefore aids in the interpretation of experimental results, as is clearly demonstrated in the results of this work.

The effects of plants(Typha Latifolia)and root-bed medium on the treatment of domestic sewage within a vertical flow constructed wetland /

The effect that plants {Typha latifolia) as well as root-bed medium physical and chemical characteristics have on the treatment of primary treated domestic wastewater within a vertical flow constructed wetland system was investigated. Five sets of cells, with two cells in each set, were used. Each cell was made of concrete and measured 1 .0 m X 1 .0 m and was 1.3 m deep. Four different root-bed media were tested : Queenston Shale, Fonthill Sand, Niagara Shale and a Michigan Sand. Four of the sets contained plants and a single type of root-bed medium. The influence of plants was tested by operating a Queenston Shale set without plants. Due to budget constraints no replicates were constructed. All of the sets were operated independently and identically for twenty-eight months. Twelve months of data are presented here, collected after 16 months of continuous operation. Root-bed medium type did not influence BOD5 removal. All of the sets consistently met Ontario Ministry of Environment (MOE) requirements (<25 mg/L) for BOD5 throughout the year. The 12 month average BOD5 concentration from all sets with plants was below 2.36 mg/L. All of the sets were within MOE discharge requirements (< 25 mg/L) for suspended solids with set effluent concentrations ranging from 1.53 to 14.80 mg/L. The Queenston Shale and Fonthill Sand media removed the most suspended solids while the Niagara Shale set produced suspended solids. The set containing Fonthill Sand was the only series to meet MOE discharge requirements (< Img/L) for total phosphorus year-round with a twelve month mean effluent concentration of 0.23 mg/L. Year-round all of the root-bed media were well below MOE discharge requirements (< 20mg/L in winter and < 10 mg/L in sumnner) for ammonium. The Queenston Shale and Fonthill Sand sets removed the most total nitrogen. Plants had no effect on total nitrogen removal, but did influence how nitrogen was cycled within the system. Plants increased the removal of suspended solids by 14%, BOD5 by 10% and total phosphorus by 22%. Plants also increased the amount of dissolved oxygen that entered the system. During the plant growing season removal of total phosphorus was better in all sets with plants regardless of media type. The sets containing Queenston Shale and Fonthill Sand media achieved the best results and plants in the Queenston Shale set increased treatment efficiency for every parameter except nitrogen. Vertical flow wetland sewage treatment systems can be designed and built to consistently meet MOE discharge requirements year-round for BOD5, suspended solids, total phosphorus and ammonium. This system Is generally superior to the free water systems and sub-surface horizontal flow systems in cold climate situations.