289 research outputs found
Reconfigurable quadruple quantum dots in a silicon nanowire transistor
We present a novel reconfigurable metal-oxide-semiconductor multi-gate
transistor that can host a quadruple quantum dot in silicon. The device consist
of an industrial quadruple-gate silicon nanowire field-effect transistor.
Exploiting the corner effect, we study the versatility of the structure in the
single quantum dot and the serial double quantum dot regimes and extract the
relevant capacitance parameters. We address the fabrication variability of the
quadruple-gate approach which, paired with improved silicon fabrication
techniques, makes the corner state quantum dot approach a promising candidate
for a scalable quantum information architecture
Usefulness of high resolution coastal models for operational oil spill forecast: the "Full City" accident
Oil spill modeling is considered to be an important part of a decision support system (DeSS) for oil spill combatment and is useful for remedial action in case of accidents, as well as for designing the environmental monitoring system that is frequently set up after major accidents. Many accidents take place in coastal areas, implying that low resolution basin scale ocean models are of limited use for predicting the trajectories of an oil spill. In this study, we target the oil spill in connection with the "Full City" accident on the Norwegian south coast and compare operational simulations from three different oil spill models for the area. The result of the analysis is that all models do a satisfactory job. The "standard" operational model for the area is shown to have severe flaws, but by applying ocean forcing data of higher resolution (1.5 km resolution), the model system shows results that compare well with observations. The study also shows that an ensemble of results from the three different models is useful when predicting/analyzing oil spill in coastal areas
Measurement of isotope shift in Eu II
The isotope shift between singly-charged ^Eu and ^Eu in the
4f^7(^8S^o)6s^9S_4-4f^7(^8S^o)6p_1/2>(J=4) transition at 4129 A has been
measured using fast ion beam-laser technique. This Eu line has attracted
interest in connection with efforts of obtaining a cosmochronometer based on
observed Th/Eu abundance ratios. Knowledge of the isotope shift is of
importance in order to check that contaminations from line blends do not
contribute to the line intensity of Eu II. The measured value of the isotope
shift -0.1527(2) cm-1 (= -4578 MHz) is consistent with the old spectroscopic
value of Krebs and Winkler -0.1503(25) cm-1 using a Fabry Perot interferometer,
while the accuracy is improved substantially.Comment: 12 pages, in press for Physica Scripta, in swete
Anthropogenic and climatic impacts on a coastal environment in the Baltic Sea over the last 1000 years
Coastal environments have experienced large ecological changes as a result of human activities over the last 100-200 years. To understand the severity and potential consequences of such changes, paleoenvironmental records provide important contextual information. The Baltic Sea coastal zone is naturally a vulnerable system and subject to significant human-induced impacts. To put the recent environmental degradation in the Baltic coastal zone into a long-term perspective, and to assess the natural and anthropogenic drivers of environmental change, we present sedimentary records covering the last 1000 years obtained from a coastal inlet (Gasfjarden) and a nearby lake (Lake Storsjon) in Sweden. We investigate the links between a pollen-based land cover reconstruction from Lake Storsjon and paleoenvironmental variables from Gasfjarden itself, including diatom assemblages, organic carbon (C) and nitrogen (N) contents, stable C and N isotopic ratios, and biogenic silica contents. The Lake Storsjon record shows that regional land use was characterized by small-scale agricultural activity between 900 and 1400 CE, which slightly intensified between 1400 and 1800 CE. Substantial expansion of cropland was observed between 1800 and 1950 CE, before afforestation between 1950 and 2010 CE. From the Gasfjarden record, prior to 1800 CE, relatively minor changes in the diatom and geochemical proxies were found. The onset of cultural eutrophication in Gasfjarden can be traced to the 1800s and intensified land use is identified as the main driver. Anthropogenic activities in the 20th century have caused unprecedented ecosystem changes in the coastal inlet, as reflected in the diatom composition and geochemical proxies. (c) 2018 Elsevier Ltd. All rights reserved.Peer reviewe
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A qualitative analysis of personal health care challenges experienced by Iranian divorcees
Divorce, nowadays an increasingly more prevalent life event in Iran, can create poor general health among Iranian women, possibly due to bigger challenges for health-related behaviors. The aim was to explore challenges to achieve health-related behaviors as experienced by divorced Iranian women acting as household-heads. An inductive exploratory design based on qualitative content analysis was utilized. Twenty strategically selected divorced women acting as household-heads in Tehran were interviewed between September 2019 and January 2020. The divorced women experienced individual-centered and social and environmental-centered challenges concerning their health-related behaviors. Lack of competence, lack of personal control, and lack of emotional support were described as individual-centered barriers. Lack of community-based support, lack of financial support, and lack of labor market support were described as social and environmental challenges to health-related behaviors. A wide range of individual, social, and environmental-centered factors hindered divorced women acting as household-heads to engage in health-related behaviors. Therefore, person-centered interventions are necessary alongside efforts to develop appropriate policies and amend protection laws to increase the welfare and health of divorced women acting as household-heads
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Internet addiction and sleep disorders: a systematic review and meta-analysis
The pathological use of the internet – conceptualized as 'internet addiction' – might be crucial in initiating and increasing sleep disturbances in the community. While inconsistent evidence is reported regarding the association of internet addiction and sleep disturbances, severity of this association is unclear. This systematic review and meta-analysis were conducted to increase our understanding of the relationship between internet addiction and sleep disturbances. A systematic review was conducted through Scopus, PubMed Central, ProQuest, ISI Web of Knowledge, and EMBASE using keywords related to internet addiction and sleep problems. Observational studies (cohort, case-control or cross-sectional studies) focusing on association between internet addiction and sleep disturbances including sleep problems and sleep duration were selected. A meta-analysis using random-effect model was conducted to calculate the odds ratio (OR) for experiencing sleep problems and standardized mean differences (SMDs) for sleep duration.
Eligible studies (N=23) included 35,684 participants. The overall pooled OR of having sleep problems if addicted to the internet was 2.20 (95% CI: 1.77–2.74). Additionally, the overall pooled SMDs for sleep duration for the IA group compared to normal internet users was -0.24 (95% CI: -0.38, -0.10).
Results of the meta-analysis revealed a significant OR for sleep problems and a significant reduced sleep duration among individuals addicted to the internet
Abundances of Mn, Co and Eu in a sample of 20 F-G disk stars: the influence of hyperfine structure splitting
We present Mn, Co and Eu abundances for a sample of 20 disk F and G dwarfs
and subgiants with metallicities in the range -0.8 <= [Fe/H] <= +0.3. We
investigate the influence of hyperfine structure (HFS) on the derived
abundances of Mn and Co by using HFS data from different sources in the
literature, as well as calculated HFS from interaction factors A and B. Eu
abundances were obtained from spectral synthesis of one Eu II line that takes
into account HFS from a series of recent laboratory measurements. For the lines
analyzed in this study, we find that for manganese, the differences between
abundances obtained with different HFSs are no larger than 0.10 dex. Our cobalt
abundances are even less sensitive to the choice of HFS than Mn, presenting a
0.07 dex maximum difference between determinations with different HFSs.
However, the cobalt HFS data from different sources are significantly
different. Our abundance results for Mn offer an independent confirmation of
the results from Prochaska & McWilliam (2000), who favour type Ia supernovae as
the main nucleosynthesis site of Mn production, in contrast to trends of Mn
versus metallicity previously reported in the literature. For Co, we obtain
[Co/Fe] ~ 0.0 in the range -0.3 < [Fe/H] < +0.3 and [Co/Fe] rising to a level
of +0.2 when [Fe/H] decreases from -0.3 to -0.8, in disagreement with recent
results in the literature. The observed discrepancies may be attributed to the
lack of HFS in the works we used for comparison. Our results for Eu are in
accordance with low-mass type II supernovae being the main site of the
r-process nucleosynthesis.Comment: 8 pages, 6 Postscript figures, accepted for publication in Astronomy
& Astrophysic
Europe's lost forests: a pollen-based synthesis for the last 11,000 years
8000 years ago, prior to Neolithic agriculture, Europe was mostly a wooded continent. Since then, its forest cover has been progressively fragmented, so that today it covers less than half of Europe’s land area, in many cases having been cleared to make way for fields and pasture-land. Establishing the origin of Europe’s current, more open land-cover mosaic requires a long-term perspective, for which pollen analysis offers a key tool. In this study we utilise and compare three numerical approaches to transforming pollen data into past forest cover, drawing on >1000 14C-dated site records. All reconstructions highlight the different histories of the mixed temperate and the northern boreal forests, with the former declining progressively since ~6000 years ago, linked to forest clearance for agriculture in later prehistory (especially in northwest Europe) and early historic times (e.g. in north central Europe). In contrast, extensive human impact on the needle-leaf forests of northern Europe only becomes detectable in the last two millennia and has left a larger area of forest in place. Forest loss has been a dominant feature of Europe’s landscape ecology in the second half of the current interglacial, with consequences for carbon cycling, ecosystem functioning and biodiversity
Bleeding from gastrointestinal angioectasias is not related to bleeding disorders - a case control study
n/aOriginal Publication:Charlotte M Hoog, Olle Brostrom, Tomas Lindahl, Andreas Hillarp, Gerd Larfars and Urban Sjoqvist, Bleeding from gastrointestinal angioectasias is not related to bleeding disorders - a case control study, 2010, BMC GASTROENTEROLOGY, (10), 113.http://dx.doi.org/10.1186/1471-230X-10-113Licensee: BioMed Centralhttp://www.biomedcentral.com
Long-term land-cover/use change in a traditional farming landscape in Romania inferred from pollen data, historical maps and satellite images
Traditional farming landscapes in the temperate
zone that have persisted for millennia can be exceptionally species-rich and are therefore key conservation targets. In contrast to Europe’s West, Eastern Europe harbours widespread traditional farming landscapes, but drastic socio-economic and political changes in the twentieth century are likely to have impacted these landscapes profoundly. We reconstructed long-term land-use/cover and biodiversity changes over the last 150 years in a traditional farming landscape of outstanding species diversity in Transylvania. We used the Regional Estimates of Vegetation Abundance from Large Sites model applied to a pollen record from the Transylvanian Plain and a suite of historical and satellite-based maps. We documented widespread changes in the extent and location of grassland and cropland, a loss of wood pastures as well as a gradual increase in forest extent. Land management in the socialist period (1947–1989) led to grassland expansion, but grassland diversity decreased due to intensive production. Land-use intensity has declined since the collapse of socialism in 1989, resulting in widespread cropland abandonment and conversion to grassland. However, these trends may be
temporary due to both ongoing woody encroachment as
well as grassland management intensification in productive areas. Remarkably, only 8% of all grasslands existed throughout the entire time period (1860–2010), highlighting the importance of land-use history when identifying target areas for conservation, given that old-growth grasslands are most valuable in terms of biodiversity. Combining datasets from different disciplines can yield important additional insights into dynamic landscape and biodiversity changes, informing conservation actions to maintain these species-rich landscapes in the longer term
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