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UCL University College London Eprints (339,845 recursos)
UCL Eprints collects the work of UCL researchers and makes it freely available over the web, helping the worldwide scholarly community to discover UCL research. Institutional repositories like UCL Eprints complement the traditional academic publishing and scholarly communications processes. They raise the visibility of research and help to maximise its impact. UCL researchers are encouraged to deposit a copy of each journal article, conference paper, working paper, and any other research output, in the UCL Eprints at the earliest opportunity, ensuring that their research reaches as wide an audience as possible.

Mostrando recursos 181 - 200 de 339,806

181. Photonic generation for multichannel THz wireless communication - Shams, H; Fice, MJ; Balakier, K; Renaud, CC; Seeds, AJ; Van Dijk, F
We experimentally demonstrate photonic generation of a multichannel THz wireless signal at carrier frequency 200 GHz, with data rate up to 75 Gbps in QPSK modulation format, using an optical heterodyne technique and digital coherent detection. BER measurements were carried out for three subcarriers each modulated with 5 Gbaud QPSK or for two subcarriers modulated with 10 Gbaud QPSK, giving a total speed of 30 Gbps or 40 Gbps, respectively. The system evaluation was also performed with three subcarriers modulated with 12.5 Gbaud QPSK (75 Gbps total) without and with 40 km fibre transmission. The proposed system enhances the capacity...

182. High temperature operation of athermal widely tuneable laser with simplified wavelength control for WDM-PON systems - Ponnampalam, L; Renaud, C; Fice, M; Seeds, A; Cush, R; Turner, R; Firth, P; Wale, M
A simplified control system is described which uses only three point calibration to maintain the wavelength of the ITU channels of an uncooled DS-DBR laser, spaced at 50GHz, over the full C-band. Wavelength is controlled mode-hop free over a temperature range of 45° to 80°C.

183. Photonic integration for millimetre-wave and THz Systems (invited) - Renaud, CC; Balakier, K; Fice, MJ; Ponnampalam, L; Seeds, AJ; Van Dijk, F; Kervella, G

184. Advanced Photonic Technologies for mmwave and THz coherent systems (invited) - Renaud, C

185. Optical injection locking of monolithically integrated photonic source for generation of high purity signals above 100 GHz - Balakier, K; Fice, MJ; Van Dijk, F; Kervella, G; Carpintero, G; Seeds, AJ; Renaud, CC

186. Cortical Mechanisms of Mirror Therapy After Stroke. - Rossiter, HE; Borrelli, MR; Borchert, RJ; Bradbury, D; Ward, NS
Background and Objective. Mirror therapy is a new form of stroke rehabilitation that uses the mirror reflection of the unaffected hand in place of the affected hand to augment movement training. The mechanism of mirror therapy is not known but is thought to involve changes in cerebral organization. We used magnetoencephalography (MEG) to measure changes in cortical activity during mirror training after stroke. In particular, we examined movement-related changes in the power of cortical oscillations in the beta (15-30 Hz) frequency range, known to be involved in movement. Methods. Ten stroke patients with upper limb paresis and 13 healthy controls...

187. Laterality and deep brain stimulation of the subthalamic nucleus: applying a dichotic listening task to patients treated for Parkinson's disease. - Sjöberg, RL; Häggström, B; Philipsson, J; Linder, J; Hariz, M; Blomstedt, P
Ear advantage during a dichotic listening task tends to mirror speech lateralization. Previous studies in stroke patients have shown that lesions in the dominant hemisphere often seem to produce changes in ear advantage. In this study six Parkinson's disease (PD) patients treated for motor symptoms with deep brain stimulation (DBS) of the left subthalamic nucleus (STN) were tested preoperatively and at approximately 6 and 18 months postoperatively with a dichotic listening task. Results show a significant decline of the right ear advantage over time. In three of the patients a right ear advantage preoperativley changed to a left ear advantage 18 months...

188. TeraHertz Phtotonics for Wireless Communications (invited) - Seeds, AJ; Sham, H; Fice, MJ; Renaud, CC

189. Hierarchical competitions subserving multi-attribute choice. - Hunt, LT; Dolan, RJ; Behrens, TE
Valuation is a key tenet of decision neuroscience, where it is generally assumed that different attributes of competing options are assimilated into unitary values. Such values are central to current neural models of choice. By contrast, psychological studies emphasize complex interactions between choice and valuation. Principles of neuronal selection also suggest that competitive inhibition may occur in early valuation stages, before option selection. We found that behavior in multi-attribute choice is best explained by a model involving competition at multiple levels of representation. This hierarchical model also explains neural signals in human brain regions previously linked to valuation, including striatum,...

190. Cross-modal effects of value on perceptual acuity and stimulus encoding. - Pooresmaeili, A; FitzGerald, TH; Bach, DR; Toelch, U; Ostendorf, F; Dolan, RJ
Cross-modal interactions are very common in perception. An important feature of many perceptual stimuli is their reward-predicting properties, the utilization of which is essential for adaptive behavior. What is unknown is whether reward associations in one sensory modality influence perception of stimuli in another modality. Here we show that auditory stimuli with high-reward associations increase the sensitivity of visual perception, even when sounds and reward associations are both irrelevant for the visual task. This increased sensitivity correlates with a change in stimulus representation in the visual cortex, indexed by increased multivariate decoding accuracy in simultaneously acquired functional MRI data. Univariate...

191. Facial Expression Influences Face Identity Recognition During the Attentional Blink. - Bach, DR; Schmidt-Daffy, M; Dolan, RJ
Emotional stimuli (e.g., negative facial expressions) enjoy prioritized memory access when task relevant, consistent with their ability to capture attention. Whether emotional expression also impacts on memory access when task-irrelevant is important for arbitrating between feature-based and object-based attentional capture. Here, the authors address this question in 3 experiments using an attentional blink task with face photographs as first and second target (T1, T2). They demonstrate reduced neutral T2 identity recognition after angry or happy T1 expression, compared to neutral T1, and this supports attentional capture by a task-irrelevant feature. Crucially, after neutral T1, T2 identity recognition was enhanced and...

192. Identification of clinical target areas in the brainstem of prion infected mice. - Mirabile, I; Jat, PS; Brandner, S; Collinge, J
While prion infection ultimately involves the entire brain, it has long been thought that the abrupt clinical onset and rapid neurological decline in laboratory rodents relates to involvement of specific critical neuroanatomical target areas. The severity and type of clinical signs, together with the rapid progression, suggest the brainstem as a candidate location for such critical areas. In this study we aimed to correlate prion pathology with clinical phenotype in order to identify clinical target areas.

193. Job demand and control in mid-life and physical and mental functioning in early old age: do childhood factors explain these associations in a British birth cohort? - von Bonsdorff, MB; Cooper, R; Kuh, D
Adverse work-related exposures have been linked with decreased physical and mental functioning in later life, however, whether childhood factors explain the associations between work exposures and functioning is unknown. Our aim was to investigate if job demand and control in mid-life were related to self-reported physical and mental functioning in early old age and whether childhood factors explained these associations.

194. Paediatric cerebral sinovenous thrombosis: findings of the International Paediatric Stroke Study. - Ichord, RN; Benedict, SL; Chan, AK; Kirkham, FJ; Nowak-Göttl, U; for the International Paediatric Stroke Study Group,
We evaluated clinical features, treatment practices and early outcome in a multicentre cohort of children with cerebral sinovenous thrombosis (CSVT).

195. Depressive Symptoms and Physical Activity During 3 Decades in Adult Life: Bidirectional Associations in a Prospective Cohort Study. - Pinto Pereira, SM; Geoffroy, MC; Power, C
Associations have been documented between physical activity and depressive symptoms, but the direction of this association is unclear.

196. 25-Hydroxyvitamin D, APOE ɛ4 genotype and cognitive function: findings from the 1958 British birth cohort. - Maddock, J; Cavadino, A; Power, C; Hyppönen, E
Both high and low vitamin D statuses have been associated with lower memory function. Apolipoprotein E (APOE) ɛ4 alleles have been associated with reduced memory function, and separately with higher vitamin D concentrations. This report aims to examine if the presence of APOE ɛ4 alleles contributes to the relationship between vitamin D and memory function. A total of 4848 (46% female) participants from the 1958 British birth cohort had information on APOE genotypes and completed memory tests at 50 years, where 4644 also had 25-hydroxyvitamin D (25(OH)D) concentrations measured at 45 years. Both low and high 25(OH)D concentrations were associated...

197. Genome-wide meta-analysis identifies six novel loci associated with habitual coffee consumption. - The Coffee and Caffeine Genetics Consortium,; Cornelis, MC; Byrne, EM; Esko, T; Nalls, MA; Ganna, A; Paynter, N; Monda, KL; Amin, N; Fischer, K; Renstrom, F; Ngwa, JS; Huikari, V; Cavadino, A; Nolte, IM; Teumer, A; Yu, K; Marques-Vidal, P; Rawal, R; Manichaikul, A; Wojczynski, MK; Vink, JM; Zhao, JH; Burlutsky, G; Lahti, J; Mikkilä, V; Lemaitre, RN; Eriksson, J; Musani, SK; Tanaka, T; Geller, F; Luan, J; Hui, J; Mägi, R; Dimitriou, M; Garcia, ME; Ho, WK; Wright, MJ; Rose, LM; Magnusson, PK; Pedersen, NL; Couper, D; Oostra, BA; Hofman, A; Ikram, MA; Tiemeier, HW; Uitterlinden, AG; van Rooij, FJ; Barroso, I; Johansson, I; Xue, L; Kaakinen, M; Milani, L; Power, C; Snieder, H; Stolk, RP; Baumeister, SE; Biffar, R; Gu, F; Bastardot, F; Kutalik, Z; Jacobs, DR; Forouhi, NG; Mihailov, E; Lind, L; Lindgren, C; Michaëlsson, K; Morris, A; Jensen, M; Khaw, KT; Luben, RN; Wang, JJ; Männistö, S; Perälä, MM; Kähönen, M; Lehtimäki, T; Viikari, J; Mozaffarian, D; Mukamal, K; Psaty, BM; Döring, A; Heath, AC; Montgomery, GW; Dahmen, N; Carithers, T; Tucker, KL; Ferrucci, L; Boyd, HA; Melbye, M; Treur, JL; Mellström, D; Hottenga, JJ; Prokopenko, I; Tönjes, A; Deloukas, P; Kanoni, S; Lorentzon, M; Houston, DK; Liu, Y; Danesh, J; Rasheed, A; Mason, MA; Zonderman, AB; Franke, L; Kristal, BS; International Parkinson's Disease Genomics Consortium (IPDGC),; North American Brain Expression Consortium (NABEC),; UK Brain Expression Consortium (UKBEC),; Karjalainen, J; Reed, DR; Westra, HJ; Evans, MK; Saleheen, D; Harris, TB; Dedoussis, G; Curhan, G; Stumvoll, M; Beilby, J; Pasquale, LR; Feenstra, B; Bandinelli, S; Ordovas, JM; Chan, AT; Peters, U; Ohlsson, C; Gieger, C; Martin, NG; Waldenberger, M; Siscovick, DS; Raitakari, O; Eriksson, JG; Mitchell, P; Hunter, DJ; Kraft, P; Rimm, EB; Boomsma, DI; Borecki, IB; Loos, RJ; Wareham, NJ; Vollenweider, P; Caporaso, N; Grabe, HJ; Neuhouser, ML; Wolffenbuttel, BH; Hu, FB; Hyppönen, E; Järvelin, MR; Cupples, LA; Franks, PW; Ridker, PM; van Duijn, CM; Heiss, G; Metspalu, A; North, KE; Ingelsson, E; Nettleton, JA; van Dam, RM; Chasman, DI
Coffee, a major dietary source of caffeine, is among the most widely consumed beverages in the world and has received considerable attention regarding health risks and benefits. We conducted a genome-wide (GW) meta-analysis of predominately regular-type coffee consumption (cups per day) among up to 91 462 coffee consumers of European ancestry with top single-nucleotide polymorphisms (SNPs) followed-up in ~30 062 and 7964 coffee consumers of European and African-American ancestry, respectively. Studies from both stages were combined in a trans-ethnic meta-analysis. Confirmed loci were examined for putative functional and biological relevance. Eight loci, including six novel loci, met GW significance (log10Bayes factor (BF)>5.64)...

198. PrP-A beta binding as a quality control for ADDL preparations - Wright, D; Purro, SA; Nicoll, AJ; Collinge, J

199. Axon-Schwann cell interactions during peripheral nerve regeneration in zebrafish larvae. - Ceci, ML; Mardones-Krsulovic, C; Sánchez, M; Valdivia, LE; Allende, ML
Peripheral nerve injuries can severely affect the way that animals perceive signals from the surrounding environment. While damage to peripheral axons generally has a better outcome than injuries to central nervous system axons, it is currently unknown how neurons re-establish their target innervations to recover function after injury, and how accessory cells contribute to this task. Here we use a simple technique to create reproducible and localized injury in the posterior lateral line (pLL) nerve of zebrafish and follow the fate of both neurons and Schwann cells.

200. Distribution of interneurons in the CA2 region of the rat hippocampus. - Botcher, NA; Falck, JE; Thomson, AM; Mercer, A
The CA2 region of the mammalian hippocampus is a unique region with its own distinctive properties, inputs and pathologies. Disruption of inhibitory circuits in this region appears to be linked with the pathology of specific psychiatric disorders, promoting interest in its local circuitry, its role in hippocampal function and its dysfunction in disease. In previous studies, CA2 interneurons, including a novel subclass of CA2 dendrite-preferring interneurons that has not been identified in other CA regions, have been shown to display physiological, synaptic and morphological properties unique to this sub-field and may therefore play a crucial role in the hippocampal circuitry....


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