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314 results on '"Alsop, D."'

53. Coupling Between Resting Cerebral Perfusion and EEG

Author

O’Gorman, R. L., primary, Poil, S.-S., additional, Brandeis, D., additional, Klaver, P., additional, Bollmann, S., additional, Ghisleni, C., additional, Lüchinger, R., additional, Martin, E., additional, Shankaranarayanan, A., additional, Alsop, D. C., additional, and Michels, L., additional

Published
2012
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58. Arterial spin labelling reveals an abnormal cerebral perfusion pattern in Parkinson's disease

Author

Melzer, T. R., primary, Watts, R., additional, MacAskill, M. R., additional, Pearson, J. F., additional, Rueger, S., additional, Pitcher, T. L., additional, Livingston, L., additional, Graham, C., additional, Keenan, R., additional, Shankaranarayanan, A., additional, Alsop, D. C., additional, Dalrymple-Alford, J. C., additional, and Anderson, T. J., additional

Published
2011
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63. A rocket-borne measurement of interstellar dust emission at high galactic latitude

Author

Lange, Andrew E, Alsop, D, Hayakawa, S, Matsumoto, T, Matsuo, H, Murakami, H, Richards, Paul L, and Sato, S

Subjects
Astronomy
Abstract

The diffuse brightness of the sky was measured in six submillimeter passbands, using a rocket-borne, liquid helium-cooled, absolute radiometer. The average brightness was reported which was observed in each of the passbands, and the dominant source of emission was tentatively identified in the three shortest wavelength bands as interstellar dust (ISD). Spacial structure was observed in these bands, as would be expected for emission from the ISD. The average column density of H I was calculated in each field of view along the scan path. All three bands show a significant correlation with H I. The obtained values are in excellent agreement with those computed for a mixture of graphite and silicate grains. A significant residual emission, not correlated with the H I column density, is evident in all three channels.

Published
1989

81. A bolometric millimeter-wave system for observations of anisotropy in the cosmic microwave background radiation on medium angular scales

Author

Fischer, M. L., primary, Alsop, D. C., additional, Cheng, E. S., additional, Clapp, A. C., additional, Cottingham, D. A., additional, Gundersen, J. O., additional, Koch, T. C., additional, Kreysa, E., additional, Meinhold, P. R., additional, Lange, A. E., additional, Lubin, P. M., additional, Richards, P. L., additional, and Smoot, G. F., additional

Published
1992
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87. Reservoir architecture of the Gharif Formation outcrops in the Southern Huqf area, Sultanate of Oman

Author

Alsop, D. B., Al Ghammari, M., Al Abri, A., Al Mahrooqi, A., Al Rawahi, H., and Salem, H.

Abstract

The Gharif Formation was deposited in the early Permian and is one of the major producing oil and gas reservoirs in the Sultanate of Oman. The Upper Gharif Unit crops out at Wadi Gharif, where a detailed outcrop characterization was undertaken. Fluvial channel sandstones, inclined heterolithic stratification (IHS) and floodplain palaeosols are the dominant facies associations. Deposition was in a low to moderate sinuosity multistorey fluvial channel belt with fluctuating water levels, allowing water retention in the channel while mud deposited on the upper portions of the point bar was exposed. Sandstone-body geometries indicate ribbon-like channels flowing in a NW orientation. The channel belt is estimated to be between 150 and 250 m wide and encased in oxidized red palaeosols. The depositional units are stacked from east to west and the scour and erosional surfaces are indicative of cut and fill under relatively low accommodation conditions. The reservoir architecture highlights the presence of potential claystone baffles in the IHS section on the margins of the point bars. Differences in grain size between the coarse-grained channel sandstones and the fine-grained IHS sandstones potentially create a permeability contrast while the inclined surfaces will affect fluid movement for both vertical and lateral flow. A deterministic surface-based model was constructed to access static connectivity of the Gharif fluvial channels.

Published
2014
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94. The parahippocampus subserves topographical learning in man.

Author

Aguirre, G K, Detre, J A, Alsop, D C, and D'Esposito, M

Abstract

The hippocampus has been proposed as the site of neural representation of large-scale environmental space, based upon the identification of place cells (neurons with receptive fields for current position in the environment) within the rat hippocampus and the demonstration that hippocampal lesions impair place learning in the rat. The inability to identify place cells within the monkey hippocampus and the observation that unilateral hippocampal lesions do not selectively impair topographic behavior in humans suggest that alternate regions may subserve this function in man. To examine the contribution of the hippocampus and adjacent medial-temporal lobe structures to topographic learning in the human, a 'virtual' maze was used as a task environment during functional magnetic resonance imaging studies. During the learning and recall of topographic information, medial-temporal activity was confined to the para- hippocampal gyri. This activity accords well with the lesion site known to produce topographical disorientation in humans. Activity was also observed in cortical areas known to project to the parahippocampus and previously proposed to contribute to a network subserving spatially guided behavior.

Published
1996
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96. Continuous arterial spin labeling perfusion magnetic resonance imaging findings in postpartum vasculopathy.

Author

Chalela, Julio A., Kasner, Scott E., McGarvey, Michael, Alsop, David C., Detre, John A., Chalela, J A, Kasner, S E, McGarvey, M, Alsop, D C, and Detre, J A

Abstract

Postpartum vasculopathy (PPV) is a rare heterogeneous nonatherosclerotic vasculopathy that occurs in the puerperium. It occurs spontaneously but may be triggered by vasoconstrictor substances. The angiographic findings vary and include narrowing of the intracranial arteries and vasospasm. The angiographic findings and the occurrence of ischemic infarcts suggest that cerebral blood flow (CBF) is impaired in PPV. The purpose of this study is to determine CBF in patients with PPV. The authors conducted a case study of 3 patients with clinical and laboratory criteria for PPV examined during a 2-year period. Clinical examination, computed tomography imaging, structural magnetic resonance imaging (MRI), cerebral angiography, and continuous arterial spin labeling perfusion (CASL-PI) MRI were performed in all patients. Mean global CBF was determined, and perfusion maps were visually inspected. The CBF values and perfusion maps were correlated with the clinical symptoms and the neuroimaging findings. Three women were studied (22, 34, and 36 years old). The median time of presentation was 4 days postpartum. One presented with intracranial hemorrhage and diffuse arterial narrowing, the other 2 with stroke-like lesions, encephalopathy, and segmental narrowing mainly in the posterior circulation. CASL-PI was performed within 1 week of symptom onset in all 3 patients. Global mean CBF values were 51.8, 39.3, and 41.8 cc/100 g/min. Although global CBF was mildly diminished, it was above ischemic levels. Visual inspection of the CASL-PI perfusion maps did not reveal areas of focal hypoperfusion or hyperperfusion. In this series of patients with PPV, CBF was close to normal. Although angiography often reveals diffuse arterial narrowing, the CBF values encountered in this study do not support a state of generalized or focal oligoemia. Vasomotor tone may change intermittently in patients with PPV. [ABSTRACT FROM AUTHOR]

Published
2001
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97. Bus Competition: Fowler Must Try Harder.

Author

ALSOP, D. F.

Abstract

Denationalisation of bus routes following the 1980 Transport Act is being hampered by Political opposition. Derrick Alsop runs a private bus service in Nottingham, he details some of the practical difficulties put in his way and shows the inadequacies of the Act. [ABSTRACT FROM AUTHOR]

Published
1982
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100. Physiological and psychological individual differences influence resting brain function measured by ASL perfusion

Author

Kano, M., Coen, S., Farmer, A., Aziz, Q., Williams, S., Alsop, D., Fukudo, S., O'Gorman, R., Kano, M., Coen, S., Farmer, A., Aziz, Q., Williams, S., Alsop, D., Fukudo, S., and O'Gorman, R.

Abstract

Effects of physiological and/or psychological inter-individual differences on the resting brain state have not been fully established. The present study investigated the effects of individual differences in basal autonomic tone and positive and negative personality dimensions on resting brain activity. Whole-brain resting cerebral perfusion images were acquired from 32 healthy subjects (16 males) using arterial spin labeling perfusion MRI. Neuroticism and extraversion were assessed with the Eysenck Personality Questionnaire-Revised. Resting autonomic activity was assessed using a validated measure of baseline cardiac vagal tone (CVT) in each individual. Potential associations between the perfusion data and individual CVT (27 subjects) and personality score (28 subjects) were tested at the level of voxel clusters by fitting a multiple regression model at each intracerebral voxel. Greater baseline perfusion in the dorsal anterior cingulate cortex (ACC) and cerebellum was associated with lower CVT. At a corrected significance threshold of p<0.01, strong positive correlations were observed between extraversion and resting brain perfusion in the right caudate, brain stem, and cingulate gyrus. Significant negative correlations between neuroticism and regional cerebral perfusion were identified in the left amygdala, bilateral insula, ACC, and orbitofrontal cortex. These results suggest that individual autonomic tone and psychological variability influence resting brain activity in brain regions, previously shown to be associated with autonomic arousal (dorsal ACC) and personality traits (amygdala, caudate, etc.) during active task processing. The resting brain state may therefore need to be taken into account when interpreting the neurobiology of individual differences in structural and functional brain activity.

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