8,304 research outputs found
The U.S. economy in 1989 and 1990: walking a fine line
Economic policy ; Forecasting
Mechanisms involved in agency attribution and their contributions to normal and abnormal experience of agency
Agency attribution is the ability to distinguish between events that occur as a result of our own actions and events that occur as a result of the actions of other people. Previous accounts of agency attribution have been mainly divided into two camps, either explaining agency in terms of high-level conscious processes (Stephens and Graham, 2000) or low-level Comparator Model (CM) processes (Frith et al. 2000). Recently, however, theorists have begun to incorporate these two approaches, but as the bulk of previous experiments fail to specify which aspects of agency are investigated, little empirical evidence exists to inform us about how these different mechanisms interact.
The aim of the current thesis was to tease apart these processes by examining high-level self/other judgments and low-level motor responses to actual and perturbed visual feedback of self-generated actions. Results from Chapters 3, 4 and 5 suggest that low-level (CM) agency mechanisms are situated in right hemisphere regions, disruption of which can reduce high-level self-judgments (Chapter 5). Proprioception was also found to negatively inform high-level judgments, as reducing proprioceptive signals increased self-judgments and visual-proprioceptive incongruence increased other judgments (Chapters 6 and 7). In terms of low-level agency mechanisms, however, visual-proprioceptive congruence was found to enhance low-level correction of visual perturbations (Chapter 8). Results from Chapter 8 and Chapter 9 provide evidence for a lack of high-level conscious awareness of low-level motor responses, as participants failed to notice their own low-level corrections (Chapter 8) and as a result failed to recognise their own actions (Chapter 9). Therefore, the current body of research provides evidence for a visual-proprioceptive comparison as an integral component of low-level (CM) agency mechanisms, and that these CM processes do not produce feelings of agency per se, but identify mismatches that inform and are then interpreted by conscious awareness
Mechanisms involved in agency attribution and their contributions to normal and abnormal experience of agency
Agency attribution is the ability to distinguish between events that occur as a result of our own actions and events that occur as a result of the actions of other people. Previous accounts of agency attribution have been mainly divided into two camps, either explaining agency in terms of high-level conscious processes (Stephens and Graham, 2000) or low-level Comparator Model (CM) processes (Frith et al. 2000). Recently, however, theorists have begun to incorporate these two approaches, but as the bulk of previous experiments fail to specify which aspects of agency are investigated, little empirical evidence exists to inform us about how these different mechanisms interact.
The aim of the current thesis was to tease apart these processes by examining high-level self/other judgments and low-level motor responses to actual and perturbed visual feedback of self-generated actions. Results from Chapters 3, 4 and 5 suggest that low-level (CM) agency mechanisms are situated in right hemisphere regions, disruption of which can reduce high-level self-judgments (Chapter 5). Proprioception was also found to negatively inform high-level judgments, as reducing proprioceptive signals increased self-judgments and visual-proprioceptive incongruence increased other judgments (Chapters 6 and 7). In terms of low-level agency mechanisms, however, visual-proprioceptive congruence was found to enhance low-level correction of visual perturbations (Chapter 8). Results from Chapter 8 and Chapter 9 provide evidence for a lack of high-level conscious awareness of low-level motor responses, as participants failed to notice their own low-level corrections (Chapter 8) and as a result failed to recognise their own actions (Chapter 9). Therefore, the current body of research provides evidence for a visual-proprioceptive comparison as an integral component of low-level (CM) agency mechanisms, and that these CM processes do not produce feelings of agency per se, but identify mismatches that inform and are then interpreted by conscious awareness
Searching for low mass objects around nearby dMe radio stars
Nearby M-dwarfs are best suited for searches of low mass companions. VLBI
phase-referencing observations with sensitive telescopes are able to detect
radio star flux-densities of tenths of mJy as well as to position the star on
the sky with submilliarcsecond precision. We have initiated a long-term
observational program, using EVN telescopes in combination with NASA DSN
dishes, to revisit the kinematics of nearby, single M dwarfs. The precision of
the astrometry allows us to search for possible companions with masses down to
1 Jupiter mass. In this contribution we report preliminary results of the first
observation epochs, in which we could detect some of the radio stars included
in our program.Comment: Proceedings of the 6th European VLBI Network Symposium, Ros E.,
Porcas R.W., Lobanov A.P., & Zensus J.A. (eds.), MPIfR, Bonn, Germany, p.
255-258 (2002). 4 pages, 3 figures, needs evn2002.cl
The Venus Balloon Project
On June 11 and 15, 1985, two instrumental balloons were released from the Soviet VEGA 1 and VEGA 2 spacecraft and deployed in the atmosphere of Venus. The VEGA probes flew by the planet on their way to a rendezvous with comet Halley in March 1986. Drifting with the wind at altitudes of 54 km, the balloons traveled one-third of the way around the planet during their 46-hour lifetimes. Sensors on-board the gondolas made periodic measurements of pressure, temperature, vertical wind velocity, cloud particle density, ambient light level, and frequency of lightning. The data were transmitted to Earth and received at the Deep Space Network (DSN) 64-m stations and at several large antennas in the USSR. Approximately 95 percent of the telemetry data were successfully decoded at the DSN complexes and in the Soviet Union, and were provided to the international science team for analysis. Very Long Baseline Interferometry (VLBI) data were acquired by 20 radio observatories around the world for the purpose of monitoring the Venus winds. The DSN 64-m subnet was part of a 15-station VLBI network organized by the Centre National d'Etudes Spatiales (CNES) of France. In addition, five antennas of the Soviet network participated. VLBI data from the CNES network are currently being processed at the Jet Propulsion Laboratory
Fat transforms ascorbic acid from inhibiting to promoting acid-catalysed N-nitrosation
<b>Background</b>: The major potential site of acid nitrosation is the proximal stomach, an anatomical site prone to
a rising incidence of metaplasia and adenocarcinoma. Nitrite, a pre-carcinogen present in saliva, can be
converted to nitrosating species and N-nitroso compounds by acidification at low gastric pH in the presence
of thiocyanate.
<b>Aims</b>: To assess the effect of lipid and ascorbic acid on the nitrosative chemistry under conditions simulating
the human proximal stomach.
<b>Methods</b>: The nitrosative chemistry was modelled in vitro by measuring the nitrosation of four secondary
amines under conditions simulating the proximal stomach. The N-nitrosamines formed were measured by gas
chromatography–ion-trap tandem mass spectrometry, while nitric oxide and oxygen levels were measured
amperometrically.
<b>Results</b>: In absence of lipid, nitrosative stress was inhibited by ascorbic acid through conversion of nitrosating
species to nitric oxide. Addition of ascorbic acid reduced the amount of N-nitrosodimethylamine formed by
fivefold, N-nitrosomorpholine by .1000-fold, and totally prevented the formation of N-nitrosodiethylamine
and N-nitrosopiperidine. In contrast, when 10% lipid was present, ascorbic acid increased the amount of Nnitrosodimethylamine,
N-nitrosodiethylamine and N-nitrosopiperidine formed by approximately 8-, 60- and
140-fold, respectively, compared with absence of ascorbic acid.
<b>Conclusion</b>: The presence of lipid converts ascorbic acid from inhibiting to promoting acid nitrosation. This
may be explained by nitric oxide, formed by ascorbic acid in the aqueous phase, being able to regenerate
nitrosating species by reacting with oxygen in the lipid phase
MMP-9 cleaves SP-D and abrogates its innate immune functions in vitro
Possession of a properly functioning innate immune system in the lung is vital to prevent infections due to the ongoing exposure of the lung to pathogens. While mechanisms of pulmonary innate immunity have been well studied, our knowledge of how these systems are altered in disease states, leading to increased susceptibility to infections, is limited. One innate immune protein in the lung, the pulmonary collectin SP-D, has been shown to be important in innate immune defense, as well as clearance of allergens and apoptotic cells. MMP-9 is a protease with a wide variety of substrates, and has been found to be dysregulated in a myriad of lung diseases ranging from asthma to cystic fibrosis; in many of these conditions, there are decreased levels of SP-D. Our results indicate that MMP-9 is able to cleave SP-D in vitro and this cleavage leads to loss of its innate immune functions, including its abilities to aggregate bacteria and increase phagocytosis by mouse alveolar macrophages. However, MMP-9-cleaved SP-D was still detected in a solid-phase E. coli LPS-binding assay, while NE-cleaved SP-D was not. In addition, MMP-9 seems to cleave SP-D much more efficiently than NE at physiological levels of calcium. Previous studies have shown that in several diseases, including cystic fibrosis and asthma, patients have increased expression of MMP-9 in the lungs as well as decreased levels of intact SP-D. As patients suffering from many of the diseases in which MMP-9 is over-expressed can be more susceptible to pulmonary infections, it is possible that MMP-9 cleavage of SP-D may contribute to this phenotype
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The Stac Fada “impact ejecta” layer: not what it seems
The Stac Fada Member (SFM) forms part of the Stoer Group of the Torridonian of NW Scotland. The SFM is unique in the Torridonian, being characterized by the presence of greenish altered glass clasts. Its origin has been debated for decades with several hypotheses being proposed but all invoking some connection with volcanic activity in the region. More recently, Amor et al. suggested that the SFM represents “a chord section through the continuous ejecta blanket surrounding an impact crater”. Here, we confirm the presence of shocked material within the SFM and then discuss its origin
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