845 research outputs found

    Entanglement trapping in a non-stationary structured reservoir

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    We study a single two-level atom interacting with a reservoir of modes defined by a reservoir structure function with a frequency gap. Using the pseudomodes technique, we derive the main features of a trapping state formed in the weak coupling regime. Utilising different entanglement measures we show that strong correlations and entanglement between the atom and the modes are in existence when this state is formed. Furthermore, an unexpected feature for the reservoir is revealed. In the long time limit and for weak coupling the reservoir spectrum is not constant in time.Comment: 10 pages, 16 figure

    Local in time master equations with memory effects: Applicability and interpretation

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    Non-Markovian local in time master equations give a relatively simple way to describe the dynamics of open quantum systems with memory effects. Despite their simple form, there are still many misunderstandings related to the physical applicability and interpretation of these equations. Here we clarify these issues both in the case of quantum and classical master equations. We further introduce the concept of a classical non-Markov chain signified through negative jump rates in the chain configuration.Comment: Special issue on loss of coherence and memory effects in quantum dynamics, J. Phys. B., to appea

    Eight years of sub-micrometre organic aerosol composition data from the boreal forest characterized using a machine-learning approach

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    The Station for Measuring Ecosystem-Atmosphere Relations (SMEAR) II, located within the boreal forest of Finland, is a unique station in the world due to the wide range of long-term measurements tracking the Earth-atmosphere interface. In this study, we characterize the composition of organic aerosol (OA) at SMEAR II by quantifying its driving constituents. We utilize a multi-year data set of OA mass spectra measured in situ with an Aerosol Chemical Speciation Monitor (ACSM) at the station. To our knowledge, this mass spectral time series is the longest of its kind published to date. Similarly to other previously reported efforts in OA source apportionment from multi-seasonal or multi-annual data sets, we approached the OA characterization challenge through positive matrix factorization (PMF) using a rolling window approach. However, the existing methods for extracting minor OA components were found to be insufficient for our rather remote site. To overcome this issue, we tested a new statistical analysis framework. This included unsupervised feature extraction and classification stages to explore a large number of unconstrained PMF runs conducted on the measured OA mass spectra. Anchored by these results, we finally constructed a relaxed chemical mass balance (CMB) run that resolved different OA components from our observations. The presented combination of statistical tools provided a data-driven analysis methodology, which in our case achieved robust solutions with minimal subjectivity. Following the extensive statistical analyses, we were able to divide the 2012-2019 SMEAR II OA data (mass concentration interquartile range (IQR): 0.7, 1.3, and 2.6 mu gm(-3)) into three sub-categories - low-volatility oxygenated OA (LV-OOA), semi-volatile oxygenated OA (SV-OOA), and primary OA (POA) - proving that the tested methodology was able to provide results consistent with literature. LV-OOA was the most dominant OA type (organic mass fraction IQR: 49 %, 62 %, and 73 %). The seasonal cycle of LV-OOA was bimodal, with peaks both in summer and in February. We associated the wintertime LV-OOA with anthropogenic sources and assumed biogenic influence in LV-OOA formation in summer. Through a brief trajectory analysis, we estimated summertime natural LV-OOA formation of tens of ngm 3 h 1 over the boreal forest. SV-OOA was the second highest contributor to OA mass (organic mass fraction IQR: 19 %, 31 %, and 43 %). Due to SV-OOA's clear peak in summer, we estimate biogenic processes as the main drivers in its formation. Unlike for LV-OOA, the highest SV-OOA concentrations were detected in stable summertime nocturnal surface layers. Two nearby sawmills also played a significant role in SV-OOA production as also exemplified by previous studies at SMEAR II. POA, taken as a mix of two different OA types reported previously, hydrocarbon-like OA (HOA) and biomass burning OA (BBOA), made up a minimal OA mass fraction (IQR: 2 %, 6 %, and 13 %). Notably, the quantification of POA at SMEAR II using ACSM data was not possible following existing rolling PMF methodologies. Both POA organic mass fraction and mass concentration peaked in winter. Its appearance at SMEAR II was linked to strong southerly winds. Similar wind direction and speed dependence was not observed among other OA types. The high wind speeds probably enabled the POA transport to SMEAR II from faraway sources in a relatively fresh state. In the event of slower wind speeds, POA likely evaporated and/or aged into oxidized organic aerosol before detection. The POA organic mass fraction was significantly lower than reported by aerosol mass spectrometer (AMS) measurements 2 to 4 years prior to the ACSM measurements. While the co-located long-term measurements of black carbon supported the hypothesis of higher POA loadings prior to year 2012, it is also possible that short-term (POA) pollution plumes were averaged out due to the slow time resolution of the ACSM combined with the further 3 h data averaging needed to ensure good signal-to-noise ratios (SNRs). Despite the length of the ACSM data set, we did not focus on quantifying long-term trends of POA (nor other components) due to the high sensitivity of OA composition to meteorological anomalies, the occurrence of which is likely not normally distributed over the 8-year measurement period. Due to the unique and realistic seasonal cycles and meteorology dependences of the independent OA subtypes complemented by the reasonably low degree of unexplained OA variability, we believe that the presented data analysis approach performs well. Therefore, we hope that these results encourage also other researchers possessing several-yearlong time series of similar data to tackle the data analysis via similar semi- or unsupervised machine-learning approaches. This way the presented method could be further optimized and its usability explored and evaluated also in other environments.Peer reviewe

    Vertical profiles of volatile organic compounds and fine particles in atmospheric air by using an aerial drone with miniaturized samplers and portable devices

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    The increase in volatile organic compound (VOC) emissions released into the atmosphere is one of the main threats to human health and climate. VOCs can adversely affect human life through their contribution to air pollution directly and indirectly by reacting via several mechanisms in the air to form secondary organic aerosols. In this study, an aerial drone equipped with miniaturized air-sampling systems including up to four solid-phase microextraction (SPME) Arrows and four in-tube extraction (ITEX) samplers for the collection of VOCs, along with portable devices for the real-time measurement of black carbon (BC) and total particle numbers at high altitudes was exploited. In total, 135 air samples were collected under optimal sampling conditions from 4 to 14 October 2021 at the boreal forest SMEAR II station, Finland. A total of 48 different VOCs, including nitrogen-containing compounds, alcohols, aldehydes, ketones, organic acids, and hydrocarbons, were detected at different altitudes from 50 to 400 m above ground level with concentrations of up to 6898 ng m−3 in the gas phase and 8613 ng m−3 in the particle phase. Clear differences in VOC distributions were seen in samples collected from different altitudes, depending on the VOC sources. It was also possible to collect aerosol particles by the filter accessory attached on the ITEX sampling system, and five dicarboxylic acids were quantified with concentrations of 0.43 to 10.9 ”g m−3. BC and total particle number measurements provided similar diurnal patterns, indicating their correlation. For spatial distribution, BC concentrations were increased at higher altitudes, being 2278 ng m−3 at 100 m and 3909 ng m−3 at 400 m. The measurements aboard the drone provided insights into horizontal and vertical variability in BC and aerosol number concentrations above the boreal forest.</p

    QTL/microarray approach using pathway information

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    <p>Abstract</p> <p>Background</p> <p>A combined quantitative trait loci (QTL) and microarray-based approach is commonly used to find differentially expressed genes which are then identified based on the known function of a gene in the biological process governing the trait of interest. However, a low cutoff value in individual gene analyses may result in many genes with moderate but meaningful changes in expression being missed.</p> <p>Results</p> <p>We modified a gene set analysis to identify intersection sets with significantly affected expression for which the changes in the individual gene sets are less significant. The gene expression profiles in liver tissues of four strains of mice from publicly available microarray sources were analyzed to detect trait-associated pathways using information on the QTL regions of blood concentrations of high density lipoproteins (HDL) cholesterol and insulin-like growth factor 1 (IGF-1). Several metabolic pathways related to HDL levels, including lipid metabolism, ABC transporters and cytochrome P450 pathways were detected for HDL QTL regions. Most of the pathways identified for the IGF-1 phenotype were signal transduction pathways associated with biological processes for IGF-1's regulation.</p> <p>Conclusion</p> <p>We have developed a method of identifying pathways associated with a quantitative trait using information on QTL. Our approach provides insights into genotype-phenotype relations at the level of biological pathways which may help to elucidate the genetic architecture underlying variation in phenotypic traits.</p

    Evaluating the effects of bilingual traffic signs on driver performance and safety

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    Variable Message Signs (VMS) can provide immediate and relevant information to road users and bilingual VMS can provide great flexibility in countries where a significant proportion of the population speak an alternative language to the majority. The study reported here evaluates the effect of various bilingual VMS configurations on driver behaviour and safety. The aim of the study was to determine whether or not the visual distraction associated with bilingual VMS signs of different configurations (length, complexity) impacted on driving performance. A driving simulator was used to allow full control over the scenarios, road environment and sign configuration and both longitudinal and lateral driver performance was assessed. Drivers were able to read one and two-line monolingual signs and two-line bilingual signs without disruption to their driving behaviour. However, drivers significantly reduced their speed in order to read four-line monolingual and four-line bilingual signs, accompanied by an increase in headway to the vehicle in front. This implies that drivers are possibly reading the irrelevant text on the bilingual sign and various methods for reducing this effect are discussed

    APOE Genotypes, Lipid Profiles, and Associated Clinical Markers in a Finnish Population with Cardiovascular Disease Risk Factors

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    Introduction: The APOE Δ4 allele predisposes to high cholesterol and increases the risk for lifestyle-related diseases such as Alzheimer’s disease and cardiovascular diseases (CVDs). The aim of this study was to analyse interrelationships of APOE genotypes with lipid metabolism and lifestyle factors in middle-aged Finns among whom the CVD risk factors are common. Methods: Participants (n = 211) were analysed for APOE Δ genotypes, physiological parameters, and health- and diet-related plasma markers. Lifestyle choices were determined by a questionnaire. Results: APOE genotypes Δ3/Δ4 and Δ4/Δ4 (Δ4 group) represented 34.1% of the participants. Genotype Δ3/Δ3 (Δ3 group) frequency was 54.5%. Carriers of Δ2 (Δ2 group; Δ2/Δ2, Δ2/Δ3 and Δ2/Δ4) represented 11.4%; 1.9% were of the genotype Δ2/Δ4. LDL and total cholesterol levels were lower (p < 0.05) in the Δ2 carriers than in the Δ3 or Δ4 groups, while the Δ3 and Δ4 groups did not differ. Proportions of plasma saturated fatty acids (SFAs) were higher (p < 0.01), and omega-6 fatty acids lower (p = 0.01) in the Δ2 carriers compared with the Δ4 group. The Δ2 carriers had a higher (p < 0.05) percentage of 22:4n-6 and 22:5n-6 and a lower (p < 0.05) percentage of 24:5n-3 and 24:6n-3 than individuals without the Δ2 allele. Conclusions: The plasma fatty-acid profiles in the Δ2 group were characterized by higher SFA and lower omega-6 fatty-acid proportions. Their lower cholesterol values indicated a lower risk for CVD compared with the Δ4 group. A novel finding was that the Δ2 carriers had different proportions of 22:4n-6, 22:5n-6, 24:5n-3, and 24:6n-3 than individuals without the Δ2 allele. The significance of the differences in fatty-acid composition remains to be studied.Peer reviewe

    Developing a digital intervention for cancer survivors: an evidence-, theory- and person-based approach

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    This paper illustrates a rigorous approach to developing digital interventions using an evidence-, theory- and person-based approach. Intervention planning included a rapid scoping review which identified cancer survivors’ needs, including barriers and facilitators to intervention success. Review evidence (N=49 papers) informed the intervention’s Guiding Principles, theory-based behavioural analysis and logic model. The intervention was optimised based on feedback on a prototype intervention through interviews (N=96) with cancer survivors and focus groups with NHS staff and cancer charity workers (N=31). Interviews with cancer survivors highlighted barriers to engagement, such as concerns about physical activity worsening fatigue. Focus groups highlighted concerns about support appointment length and how to support distressed participants. Feedback informed intervention modifications, to maximise acceptability, feasibility and likelihood of behaviour change. Our systematic method for understanding user views enabled us to anticipate and address important barriers to engagement. This methodology may be useful to others developing digital interventions

    Nuorten avomuotoinen OPI-mielenterveyskuntoutus : Koettu hyöty ja vaikuttavuus sekÀ kuntoutusmallin soveltuvuus

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    OPI-hankkeen tarkoituksena oli kehittÀÀ avomuotoista kuntoutusmallia ammatillisessa koulutuksessa oleville 16–25-vuotiaille opiskelijoille, joilla oli diagnosoitu masennus- ja/tai ahdistuneisuushĂ€iriö. Kuntoutusmallilla pyrittiin tukemaan nuoria elĂ€mĂ€nhallinnassa ja opiskelussa, vahvistamaan nuoren toimintakykyĂ€ ja hyvinvointia sekĂ€ vĂ€hentĂ€mÀÀn mielenterveysongelmiin liittyviĂ€ haittoja. Vuosina 2011–2013 toteutettiin yhteensĂ€ kahdeksan avomuotoista ryhmĂ€kuntoutuskurssia, joihin kuului myös yksilökĂ€yntejĂ€ sekĂ€ verkostotapaamisia. Kurssit kestivĂ€t seurantoineen noin 1,5 vuotta ja ne toteutettiin lukukausien aikana. OPI-hankkeen yhteydessĂ€ toteutettiin arviointitutkimus, jonka tavoite oli selvittÀÀ kuntoutusmallin koettua hyötyĂ€ ja vaikuttavuutta, sidosryhmĂ€yhteistyötĂ€ sekĂ€ kuntoutusmallin soveltuvuutta vakiintuneeksi toiminnaksi. Tutkimukseen osallistui 70 kuntoutujaa. Aineistoa kerĂ€ttiin kyselylomakkeilla sekĂ€ eri tahojen haastatteluilla (kuntoutujat, projektiryhmĂ€t). Kuntoutuksen ja opiskelujen yhteen nivominen onnistui enimmĂ€kseen hyvin. RyhmĂ€ssĂ€ saatu vertaistuki koettiin kuntoutuksen suurimmaksi anniksi. Seuranta-aikana nuorten masennusoireet vĂ€henivĂ€t, elĂ€mĂ€nlaatu, itse arvioitu terveydentila sekĂ€ opiskelukyky ja kognitiivinen toimintakyky kohentuivat. Nuoret olisivat kuitenkin tarvinneet kuntoutusta jo varhaisemmassa vaiheessa. Noin kolme nuorta neljĂ€stĂ€ arvioi, ettĂ€ oli saavuttanut kuntoutukselle asettamansa tavoitteet vĂ€hintÀÀn melko hyvin. Tavoitteiden saavuttaminen ja kuntoutuksen koettu vaikuttavuus olivat yhteydessĂ€ kuntoutuksen oikea-aikaisuuteen, yhteistyöhön hoitavan tahon sekĂ€ opiskeluterveydenhuollon kanssa sekĂ€ vuorovaikutuksen onnistumiseen ohjaajan ja nuoren vĂ€lillĂ€. Tutkimuksen tulokset antavat varsin rohkaisevan kuvan oppilaitoksen kanssa yhteistyössĂ€ toimivan ja opintojen kanssa yhteen sovitetun kuntoutuksen mahdollisuuksista nuorten syrjĂ€ytymisen ehkĂ€isemisessĂ€

    The JUROGAM 3 spectrometer

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    The jurogam 3 spectrometer has been constructed for in-beam gamma-ray spectroscopy experiments in the Accelerator Laboratory of the University of Jyvaskyla, Finland. jurogam 3 consists of germanium-detector modules in a compact geometry surrounding a target to measure. rays emitted from radioactive nuclei. jurogam 3 can be employed in conjunction with one of two recoil separators, the mara vacuum-mode separator or the ritu gas-filled separator, and other ancillary devices.Peer reviewe
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