Cannabis varies considerably in levels of its two major constituent cannabinoids - (delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Recently, we found evidence that those who smoked ...cannabis containing detectable levels of CBD had fewer psychotic-like symptoms than those whose cannabis had no CBD. The present study aimed, first, to replicate those findings and, second, to determine whether protective effects of CBD may extend to other harms of cannabis, such as memory impairment and reduced psychological well-being.
A total of 120 current cannabis smokers, 66 daily users and 54 recreational users were classified into groups according to whether analysis of their hair revealed the presence or absence of CBD and high versus low levels of THC. All were assessed on measures of psychosis-like symptoms, memory (prose recall; source memory) and depression/anxiety.
Lower psychosis-like symptoms were found in those whose hair had CBD compared with those without. However, this was seen only in recreational users, who had higher levels of THC in their hair. Higher THC levels in hair were associated with increased depression and anxiety. Prose recall and source memory were poorer in daily users with high THC levels in hair while recognition memory was better in individuals with CBD present in hair.
CBD attenuates the psychotic-like effects of cannabis over time in recreational users. Higher THC negatively impacts on memory and psychological well-being. These findings raise concerns for the harms stemming from use of varieties such as 'skunk' (sensimillia), which lack any CBD but currently dominate the supply of cannabis in many countries.
Persecutory delusions are a key psychotic experience. A reasoning style known as 'jumping to conclusions' (JTC) - limited information gathering before reaching certainty in decision making - has been ...identified as a contributory factor in the occurrence of delusions. The cognitive processes that underpin JTC need to be determined in order to develop effective interventions for delusions. In the current study two alternative perspectives were tested: that JTC partially results from impairment in information-processing capabilities and that JTC is a motivated strategy to avoid uncertainty.
A group of 123 patients with persistent persecutory delusions completed assessments of JTC (the 60:40 beads task), IQ, working memory, intolerance of uncertainty, and psychiatric symptoms. Patients showing JTC were compared with patients not showing JTC.
A total of 30 (24%) patients with delusions showed JTC. There were no differences between patients who did and did not jump to conclusions in overall psychopathology. Patients who jumped to conclusions had poorer working memory performance, lower IQ, lower intolerance of uncertainty and lower levels of worry. Working memory and worry independently predicted the presence of JTC.
Hasty decision making in patients with delusions may partly arise from difficulties in keeping information in mind. Interventions for JTC are likely to benefit from addressing working memory performance, while in vivo techniques for patients with delusions will benefit from limiting the demands on working memory. The study provides little evidence for a contribution to JTC from top-down motivational beliefs about uncertainty.
We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ...ultra-short-period Jupiter orbiting a bright (V = 11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 ± 0.078 MJ planet in a grazing transit configuration with an impact parameter of b = 1.17−0.08+0.10. As a result the radius is poorly constrained, 2.03−0.49+0.61RJ. The planet’s distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Qs′ = 107 − 109. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 ± 0.13 MJ and a radius of 1.29 ± 0.02 RJ. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V = 12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V = 12.4 G-type star. It has a mass of 0.79 ±0.06 MJ and a radius of 1.09−0.05+0.08RJ. Despite having the longest orbital period (P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with Fe / H ranging from 0.18 to0.24.
Three short-period Jupiters from TESS Nielsen, L. D.; Brahm, R.; Bouchy, F. ...
Astronomy and astrophysics (Berlin),
07/2020, Letnik:
639
Journal Article, Web Resource
Recenzirano
Odprti dostop
We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ...ultra-short-period Jupiter orbiting a bright (
V
= 11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 ± 0.078
M
J
planet in a grazing transit configuration with an impact parameter of
b
= 1.17
−0.08
+0.10
. As a result the radius is poorly constrained, 2.03
−0.49
+0.61
R
J
. The planet’s distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of
Q
s
′
= 10
7
− 10
9
. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 ± 0.13
M
J
and a radius of 1.29 ± 0.02
R
J
. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (
V
= 12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a
V
= 12.4 G-type star. It has a mass of 0.79 ±0.06
M
J
and a radius of 1.09
−0.05
+0.08
R
J
. Despite having the longest orbital period (
P
= 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with Fe / H ranging from 0.18 to0.24.
Aims: Research into interpersonal processes involved in paranoia remains limited. This study aimed to assess the feasibility of using interactive virtual reality in a clinical sample with psychosis ...and persecutory delusions. The study aimed to replicate an experiment which found healthy individuals high in paranoia showed a hypersensitivity to contingent behaviour which increased their perceived trust towards the avatar. A further aim was to investigate the impact of self-focused attention on the perception of interpersonal contingency and trust. Method: Eighteen male participants with psychosis and paranoia completed the virtual reality exercise. Participants entered a virtual flat and interviewed a virtual flatmate whose non-verbal responses were either high or low in contingency in relation to the participant. Trust towards the avatar was measured by self-report and behaviour towards the virtual flatmate, operationalised as interpersonal distance. Focus of attention, affect and immersion in the virtual reality scenario were assessed. Results: Overall, participants enjoyed and were immersed in the interactive virtual reality environment. Interpersonal distance was predicted by severity of persecutory delusions and negative affect. Exploratory graphic analyses showed no evidence of hypersensitivity to avatar contingency or moderating effect of self-focus attention. Persecutory delusion severity was associated with other-focus attention, which in turn, unexpectedly, predicted higher self-focused attention. Conclusions: Interactive virtual reality is a safe and feasibility research tool for individuals with clinical paranoia. Severity of persecutory delusions, rather than environmental manipulation, predicted trust. However, the lack of power in the current study prevents clear conclusions about the impact of interpersonal contingency on trust in clinical paranoia from being drawn. Replication is required with a larger sample and a more ambiguous scenario.
We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ...ultra-short-period Jupiter orbiting a bright (V=11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 +/- 0.078 Mjup planet in a grazing transit configuration with an impact parameter of b = 1.17 +0.10/-0.08. As a result the radius is poorly constrained, 2.03 +0.61/-0.49 Rjup. The planet's distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Qs' = 10^7 - 10^9. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 +/- 0.13 Mjup and a radius of 1.29 +/- 0.02 Rjup. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V=12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V=12.4 G-type star. It has a mass of 0.79 +/- 0.06 Mjup and a radius of 1.09 +0.08/-0.05 Rjup. Despite having the longest orbital period (P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with Fe/H ranging from 0.18 - 0.24.
Mass balance of the Antarctic ice sheet Wingham, D.J; Shepherd, A; Muir, A ...
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
07/2006, Letnik:
364, Številka:
1844
Journal Article
Recenzirano
The Antarctic contribution to sea-level rise has long been uncertain. While regional variability in ice dynamics has been revealed, a picture of mass changes throughout the continental ice sheet is ...lacking. Here, we use satellite radar altimetry to measure the elevation change of 72% of the grounded ice sheet during the period 1992-2003. Depending on the density of the snow giving rise to the observed elevation fluctuations, the ice sheet mass trend falls in the range −5-+85 Gt yr−1. We find that data from climate model reanalyses are not able to characterise the contemporary snowfall fluctuation with useful accuracy and our best estimate of the overall mass trend-growth of 27±29 Gt yr−1-is based on an assessment of the expected snowfall variability. Mass gains from accumulating snow, particularly on the Antarctic Peninsula and within East Antarctica, exceed the ice dynamic mass loss from West Antarctica. The result exacerbates the difficulty of explaining twentieth century sea-level rise.
This paper describes the CryoSat satellite mission, due for launch in 2005, whose aim is to accurately determine the trends in Earth’s continental and marine ice fields. The paper’s purpose is to ...provide scientific users of the CryoSat data with a description of the design and operation of the SIRAL radar and the CryoSat platform, the data products, and the expected error budget. The ‘low-resolution mode’ (LRM), ‘synthetic aperture mode’ (SARM) and “synthetic aperture interferometric mode’ (SARInM) of the SIRAL radar are described, together with its system parameters, its antenna gain pattern and interferometer phase difference pattern, and its calibration modes. The orbit is described, together with the platform attitude and altitude control law and control systems, and the expected pointing and altitude knowledge. The geographical masks that are used to determine acquisitions in the three SIRAL modes are described. The SIRAL data products, and the processing applied to produce them, are described.
Level 1b,
level 2 and
higher-level products are described in turn, with a particular emphasis on the new procedures applied to the SARInM and SARM processing over ice surfaces. The beam forming and multi-looking is summarised, and a description is given of the behaviour of the SARM and SARInM echoes over idealised surfaces. These inform descriptions of the elevation retrievals of the
level 2 processing, including the SARInM retrieval of interferometric phase. The combination of these data, through cross-over analysis over continental ice sheets, and through averaging over sea-ice, to determine areal averages of ice sheet elevation change or sea-ice thickness, is described. The error budget in these higher-level products is described, together with its breakdown into errors arising from the instrument and errors arising from the retrievals. The importance of the co-variance of these errors in determining the final error is stressed. The description of the errors also includes a summary of the experiments required following the launch to validate the CryoSat mission data. An estimate of the mission performance over ice surfaces is made at various spatial scales, and it is concluded that even the relatively short, three-year duration of the CryoSat mission will allow it to make an important scientific contribution, particularly when combined with results from earlier satellite missions.
We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic ...adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good agreement between different satellite methods—especially in Greenland and West Antarctica—and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by -152 ± 49, +14 ± 43, -65 ± 26, and -20 ± 14 gigatonnes year⁻¹, respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year⁻¹ to the rate of global sea-level rise.
A dense grid of ice‐penetrating radar sections acquired over Pine Island Glacier, West Antarctica has revealed a network of sinuous subglacial channels, typically 500 m to 3 km wide, and up to 200 m ...high, in the ice‐shelf base. These subglacial channels develop while the ice is floating and result from melting at the base of the ice shelf. Above the apex of most channels, the radar shows isolated reflections from within the ice shelf. Comparison of the radar data with acoustic data obtained using an autonomous submersible, confirms that these echoes arise from open basal crevasses 50–100 m wide aligned with the subglacial channels and penetrating up to 1/3 of the ice thickness. Analogous sets of surface crevasses appear on the ridges between the basal channels. We suggest that both sets of crevasses were formed during the melting of the subglacial channels as a response to vertical flexing of the ice shelf toward the hydrostatic condition. Finite element modeling of stresses produced after the formation of idealized basal channels indicates that the stresses generated have the correct pattern and, if the channels were formed sufficiently rapidly, would have sufficient magnitude to explain the formation of the observed basal and surface crevasse sets. We conclude that ice‐shelf basal melting plays a role in determining patterns of surface and basal crevassing. Increased delivery of warm ocean water into the sub‐ice shelf cavity may therefore cause not only thinning but also structural weakening of the ice shelf, perhaps, as a prelude to eventual collapse.
Key Points
Ocean melting from an ice shelf base causes surface and basal crevassing
Basal crevassing can be explained by finite‐element modeling
Increased melting of ice shelves may eventually cause them to collapse
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