2,889 research outputs found
Judicial deference at work: Some reflections on Chan Kin Sum and Kong Yun Ming
No full text"Due deference" - the giving of appropriate weight to the government's judgment in the court's reasoning - is a tool that courts use to maintain the separation of powers in constitutional rights review. This note aims to provide a theoretical framework for understanding the issue of deference, and to analyse the Court of First Instance (CFI)'s approach to deference in two recent cases, Chan Kin Sum and Kong Yun Ming. The author argues that the CFI has adopted a spatial approach that failed to specify the contested issues that called for deference, inappropriately considered democratic legitimacy as a factor for deference and made broad presumptions about the democratic character of primary decisions. This approach may lead to an over-deferential attitude that threatens the separation of powers, and the malleability of the approach may be subject to courts' manipulation. The author argues for a more context-sensitive approach based purely on institutional factors.published_or_final_versio
Resting-State Network Topology Differentiates Task Signals across the Adult Life Span
No full textBrain network connectivity differs across individuals. For example, older adults exhibit less segregated resting-state subnetworks relative to younger adults (Chan et al., 2014). It has been hypothesized that individual differences in network connectivity impact the recruitment of brain areas during task execution. While recent studies have described the spatial overlap between resting-state functional correlation (RSFC) subnetworks and task-evoked activity, it is unclear whether individual variations in the connectivity pattern of a brain area (topology) relates to its activity during task execution. We report data from 238 cognitively normal participants (humans), sampled across the adult life span (20–89 years), to reveal that RSFC-based network organization systematically relates to the recruitment of brain areas across two functionally distinct tasks (visual and semantic). The functional activity of brain areas (network nodes) were characterized according to their patterns of RSFC: nodes with relatively greater connections to nodes in their own functional system (“non-connector” nodes) exhibited greater activity than nodes with relatively greater connections to nodes in other systems (“connector” nodes). This “activation selectivity” was specific to those brain systems that were central to each of the tasks. Increasing age was accompanied by less differentiated network topology and a corresponding reduction in activation selectivity (or differentiation) across relevant network nodes. The results provide evidence that connectional topology of brain areas quantified at rest relates to the functional activity of those areas during task. Based on these findings, we propose a novel network-based theory for previous reports of the “dedifferentiation” in brain activity observed in aging.SIGNIFICANCE STATEMENTSimilar to other real-world networks, the organization of brain networks impacts their function. As brain network connectivity patterns differ across individuals, we hypothesized that individual differences in network connectivity would relate to differences in brain activity. Using functional MRI in a group of individuals sampled across the adult life span (20–89 years), we measured correlations at rest and related the functional connectivity patterns to measurements of functional activity during two independent tasks. Brain activity varied in relation to connectivity patterns revealed by large-scale network analysis. This relationship tracked the differences in connectivity patterns accompanied by older age, providing important evidence for a link between the topology of areal connectivity measured at rest and the functional recruitment of these areas during task performance.</jats:p
Differences in Radiative Forcing, Not Sensitivity, Explain Differences in Summertime Land Temperature Variance Change Between CMIP5 and CMIP6
No full text© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chan, D., Rigden, A., Proctor, J., Chan, P. W., & Huybers, P. Differences in radiative forcing, not sensitivity, explain differences in summertime land temperature variance change between CMIP5 and CMIP6. Earth’s Future, 10(2), (2022): e2021EF002402, https://doi.org/10.1029/2021EF002402.How summertime temperature variability will change with warming has important implications for climate adaptation and mitigation. CMIP5 simulations indicate a compound risk of extreme hot temperatures in western Europe from both warming and increasing temperature variance. CMIP6 simulations, however, indicate only a moderate increase in temperature variance that does not covary with warming. To explore this intergenerational discrepancy in CMIP results, we decompose changes in monthly temperature variance into those arising from changes in sensitivity to forcing and changes in forcing variance. Across models, sensitivity increases with local warming in both CMIP5 and CMIP6 at an average rate of 5.7 ([3.7, 7.9]; 95% c.i.) × 10−3°C per W m−2 per °C warming. We use a simple model of moist surface energetics to explain increased sensitivity as a consequence of greater atmospheric demand (∼70%) and drier soil (∼40%) that is partially offset by the Planck feedback (∼−10%). Conversely, forcing variance is stable in CMIP5 but decreases with warming in CMIP6 at an average rate of −21 ([−28, −15]; 95% c.i.) W2 m−4 per °C warming. We examine scaling relationships with mean cloud fraction and find that mean forcing variance decreases with decreasing cloud fraction at twice the rate in CMIP6 than CMIP5. The stability of CMIP6 temperature variance is, thus, a consequence of offsetting changes in sensitivity and forcing variance. Further work to determine which models and generations of CMIP simulations better represent changes in cloud radiative forcing is important for assessing risks associated with increased temperature variance.This study was supported by the Harvard Global Institute and NSF (Award 1903657). D. Chan was also supported by the Woods Hole Oceanographic Institute Weston Howland Jr. Postdoctoral Fellowship
Socioeconomic status moderates age-related differences in the brain’s functional network organization and anatomy across the adult lifespan
No full textSignificance
An individual’s socioeconomic status (SES) is a central feature of their environmental surroundings and has been shown to relate to the development and maturation of their brain in childhood. Here, we demonstrate that an individual’s present (adult) SES relates to their brain function and anatomy across a broad range of middle-age adulthood. In middle-aged adults (35–64 years), lower SES individuals exhibit less organized functional brain networks and reduced cortical thickness compared with higher SES individuals. These relationships cannot be fully explained by differences in health, demographics, or cognition. Additionally, childhood SES does not explain the relation between SES and brain network organization. These observations provide support for a powerful relationship between the environment and the brain that is evident in adult middle age.</jats:p
Aromatic hydrocarbons as ozone precursors before and after outbreak of the 2008 financial crisis in the Pearl River Delta region, south China
No full textAuthor name used in this publication: Chan, LoyinAuthor name used in this publication: Frank S. C. Lee2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishedVoR allowe
C∞-Invariants on the Space of Loops
No full textWe compute all C∞-invariants on the space of imbeddings C∞(S¹, S), where S is a connected orientable surface. [ABSTRACT FROM AUTHOR
Stretchable electronics on another level
No full textA multifunctional stretchable electronic system, which can be used to monitor vital signs and build human?machine interfaces, can be created through the vertical stacking of highly integrated layers of soft electronics. (c) 2018, The Author(s)11scopu
The in vivo characterisation of a C-domain specific ACE inhibitor
No full textIncludes bibliographical references.The ACE protein is a zinc-dependent dipeptidyl carboxypeptidase comprised of two homologous domains termed the C- and N-domain. The C-domain is primarily responsible for the catalytic production of Ang II, while the tetrapeptide acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) is predominantly cleaved by the N-domain, and both domains play a role in the metabolism of vasodilatory peptide bradykinin. In the event of myocardial infarction (MI), cardiac output and blood pressure decreases, resulting in activation of the RAS and an increase in both Ang II production and bradykinin metabolism. While initially compensatory, prolonged RAS activation has been shown to have long-term detrimental effects, and pharmaceutical intervention in the form of ACE inhibition is the first line treatment following an MI event. The ACE inhibitors currently in clinical use target both domains equally, and it has been suggested that the major side-effects of this drug class are largely attributable to the inhibition of bradykinin breakdown. A novel C-domain selective ACE inhibitor lisinopril-Trp (lisW-S) incorporates a tryptophan moiety into the P2' position of the clinically available ACE inhibitor lisinopril
The kinetics and mechanisms of destabilisation and aggregation of microcolloidal iron and associated phosphate during simulated estuarine mixing
No full textThe removal of iron from the <0.45µm fraction of Tamar River water on addition of both calcium chloride solution and sea water was studied using a continuous autoanalytical system. The addition of increasing concentrations of either calcium ions or sea water caused increased iron removal, but at all of the concentrations studied a fraction of iron was found to remain within the <0.45µm fraction (termed the residualor unreactive fraction). Storage time was shown to have a marked effect on the residual concentration. Kinetic analysis of the experimental results showed that when a residual fraction was taken into account, the data could be described by either a first or second order kinetic model. The first order model gave an approximately linear increase in rate constant with increasing concentrations of calcium ions or sea water, ranging from 1.02 x 10-3 to 6.14 x 10-3 s-1 for the addition of calcium ions and from 3.97 x 10-3 to 6.95 x 10-3 s-1 for the addition of seawater. The second order rate constant also showed an increase with increasing calcium concentration, from 3.95 x 10-5 to 3.02 x 10-4 l mol-1 s-1 . When the first and second order profiles were studied and the fit of the model to the experimental residual values was considered, the first order was shown to be a better descriptor ofthe observed removal of microcolloidal iron. A comparative study was made of iron removal under different conditions of simulated estuarine mixing, following the procedures of Fox & Wofsy (Geochim. Cosmochim. Acta, 1983, vol 47 p211), Mayer (Geochim. Cosmochim. Acta, 1982, vol 46 p2527), Hunter & Leonard (Geochim. Cosmochim. Acta, 1988, vol 52 pi 123) - all using 'discrete sampling during mixing and Duffy (PhD Thesis, University of Southampton) - using continuous sampling with more rapid mixing. Variations among the 'discrete' methods are small relative to those between them and the method of Duffy (1985) e.g. 65 % for the 'continuous' method as compared with 36%, at a salinity of 5, and the first order rate constant was seen to be about an order of magnitude greater for the 'continuous' method e.g. 3.97 x 10-3 s-1 as compared with 1.97 x 10-4 s-1, at a salinity of 5. Further experiments looking specifically at the effect of stirring rate on a 'discrete' sampling method concurred with these observations. In experiments carried out at a salinity of 8, the iron removal increased from 44% to 55% and the first order rate constant increased from 2.96 x 10-3 to 3.58 x 10-3 s-1 as a result of a relative increase in stirring rate from 1 to 5. The fact that the first order rate constant for iron removal varied with the energy of the system, even in the least energetic system studied, and that under all conditions the first order model provided the best descriptor of the observed process, showed that the mechanism of microcolloidal aggregation under all these conditions could not be accounted for by Brownian Motion. Shear must therefore be a significant factor and it was concluded that none of the systems studied could afford a test of kinetic order under conditions where Brownian Motion dominantly accounts for particle collisions. The experiments, however, are still of relevance to environmental conditions, since estuarine mixing is greatly influenced by turbulence due to tidal energy and wind stress. Phosphate behaviour was studied concurrently with that of iron and both the percentage removal and kinetic rate constants showed comparable dependence on calcium ion / sea water concentration, although the percentage phosphate removal was consistently lower than that observed for iron. Kinetic rate constants ranged from 0.0019 to 0.0179 s-1 for the first order model and 0.29 x 10-4 to 5.3 x 10-4 1 mol-1 s-1 for second order. When the removal profiles were studied and the fit of the first and second order models to the experimental residual values was considered, the first order model was again shown to be a better descriptor of the observed removal. Phosphate behaviour remained essentially unaffected by changes in experimental methodologies or stirring rate. The factor which most affected iron (stirring) had no major systematic effect on phosphate and therefore it must be concluded that the results indicate a co-removal of phosphate during iron colloid aggregation rather than removal of a common colloidal population containing both constituents
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