123 research outputs found
Bistable defect structures in blue phase devices
Blue phases (BPs) are liquid crystals made up by networks of defects, or
disclination lines. While existing phase diagrams show a striking variety of
competing metastable topologies for these networks, very little is known as to
how to kinetically reach a target structure, or how to switch from one to the
other, which is of paramount importance for devices. We theoretically identify
two confined blue phase I systems in which by applying an appropriate series of
electric field it is possible to select one of two bistable defect patterns.
Our results may be used to realise new generation and fast switching
energy-saving bistable devices in ultrathin surface treated BPI wafers.Comment: 4 pages, 3 figures. Accepted for publication in Phys. Rev. Let
A wavelet approach for estimating chlorophyll-a from inland waters with reflectance spectroscopy
Spatio-temporal impact of climate change on the groundwater system
Given the importance of groundwater for food production
and drinking water supply, but also for the survival
of groundwater dependent terrestrial ecosystems (GWDTEs)
it is essential to assess the impact of climate change on this
freshwater resource. In this paper we study with high temporal
and spatial resolution the impact of 28 climate change
scenarios on the groundwater system of a lowland catchment
in Belgium. Our results show for the scenario period
2070–2101 compared with the reference period 1960–
1991, a change in annual groundwater recharge between
−20% and +7%. On average annual groundwater recharge
decreases 7%. In most scenarios the recharge increases during
winter but decreases during summer. The altered recharge
patterns cause the groundwater level to decrease significantly
from September to January. On average the groundwater
level decreases about 7 cm with a standard deviation between
the scenarios of 5 cm. Groundwater levels in interfluves and
upstream areas are more sensitive to climate change than
groundwater levels in the river valley. Groundwater discharge
to GWDTEs is expected to decrease during late summer and
autumn as much as 10%, though the discharge remains at
reference-period level during winter and early spring. As
GWDTEs are strongly influenced by temporal dynamics of
the groundwater system, close monitoring of groundwater
and implementation of adaptive management measures are
required to prevent ecological loss
Simulation des pertes d’eau de pluie liées à l’interception par la végétation urbaine, basée sur l’acquisition de données in situ et de télédétection
Four point function of R-currents in N=4 SYM in the Regge limit at weak coupling
We compute, in N=4 super Yang-Mills theory, the four point correlation
function of R-currents in the Regge limit in the leading logarithmic
approximation at weak coupling. Such a correlator is the closest analog to
photon-photon scattering within QCD, and there is a well-defined procedure to
perform the analogous computation at strong coupling via the AdS/CFT
correspondence. The main result of this paper is, on the gauge theory side, the
proof of Regge factorization and the explicit computation of the R-current
impact factors.Comment: 21 pages, 10 figures, typos correcte
Staging Bipolar Disorder.
The purpose of this study was to analyze the evidence supporting a staging model for bipolar disorder. The authors conducted an extensive Medline and Pubmed search of the published literature using a variety of search terms (staging, bipolar disorder, early intervention) to find relevant articles, which were reviewed in detail. Only recently specific proposals have been made to apply clinical staging to bipolar disorder. The staging model in bipolar disorder suggests a progression from prodromal (at-risk) to more severe and refractory presentations (Stage IV). A staging model implies a longitudinal appraisal of different aspects: clinical variables, such as number of episodes and subsyndromal symptoms, functional and cognitive impairment, comorbidity, biomarkers, and neuroanatomical changes. Staging models are based on the fact that response to treatment is generally better when it is introduced early in the course of the illness. It assumes that earlier stages have better prognosis and require simpler therapeutic regimens. Staging may assist in bipolar disorder treatment planning and prognosis, and emphasize the importance of early intervention. Further research is required in this exciting and novel area
Frontal lobe changes occur early in the course of affective disorders in young people
<p>Abstract</p> <p>Background</p> <p>More severe and persistent forms of affective disorders are accompanied by grey matter loss in key frontal and temporal structures. It is unclear whether such changes precede the onset of illness, occur early in the course or develop gradually with persistence or recurrence of illness. A total of 47 young people presenting with admixtures of depressive and psychotic symptoms were recruited from specialist early intervention services along with 33 age matched healthy control subjects. All participants underwent magnetic resonance imaging and patients were rated clinically as to current stage of illness. Twenty-three patients were identified as being at an early 'attenuated syndrome' stage, while the remaining were rated as having already reached the 'discrete disorder' or 'persistent or recurrent illness' stage. Contrasts were carried out between controls subjects and patients cohorts with attenuated syndromes and discrete disorders, separately.</p> <p>Results</p> <p>The patients that were identified as having a discrete or persisting disorder demonstrated decreased grey matter volumes within distributed frontal brain regions when contrasted to both the control subjects as well as those patients in the attenuated syndrome stage. Overall, patients who were diagnosed as more advanced in terms of the clinical stage of their illness, exhibited the greatest grey matter volume loss of all groups.</p> <p>Conclusions</p> <p>This study suggests that, in terms of frontal grey matter changes, a major transition point may occur in the course of affective illness between early attenuated syndromes and later discrete illness stages.</p
Alcator C-Mod: research in support of ITER and steps beyond
This paper presents an overview of recent highlights from research on Alcator C-Mod. Significant progress has been made across all research areas over the last two years, with particular emphasis on divertor physics and power handling, plasma–material interaction studies, edge localized mode-suppressed pedestal dynamics, core transport and turbulence, and RF heating and current drive utilizing ion cyclotron and lower hybrid tools. Specific results of particular relevance to ITER include: inner wall SOL transport studies that have led, together with results from other experiments, to the change of the detailed shape of the inner wall in ITER; runaway electron studies showing that the critical electric field required for runaway generation is much higher than predicted from collisional theory; core tungsten impurity transport studies reveal that tungsten accumulation is naturally avoided in typical C-Mod conditions.United States. Department of Energy (DE-FC02-99ER54512-CMOD)United States. Department of Energy (DE-AC02-09CH11466)United States. Department of Energy (DE-FG02-96ER-54373)United States. Department of Energy (DE-FG02-94ER54235
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