1,221 research outputs found
Cross-coupling effects in circuit-QED stimulated Raman adiabatic passage
Stimulated Raman adiabatic passage is a quantum protocol that can be used for
robust state preparation in a three-level system. It has been commonly employed
in quantum optics, but recently this technique has drawn attention also in
circuit quantum electrodynamics. The protocol relies on two slowly varying
drive pulses that couple the initial and the target state via an intermediate
state, which remains unpopulated. Here we study the detrimental effect of the
parasitic couplings of the drives into transitions other than those required by
the protocol. The effect is most prominent in systems with almost harmonic
energy level structure, such as the transmon. We show that under these
conditions in the presence of decoherence there exists an optimal STIRAP
amplitude for population transfer.Comment: Will be published in proceedings for 28th International Conference
for Low Temperature Physic
Experimental state control by fast non-Abelian holonomic gates with a superconducting qutrit
Quantum state manipulation with gates based on geometric phases acquired
during cyclic operations promises inherent fault-tolerance and resilience to
local fluctuations in the control parameters. Here we create a general
non-Abelian and non-adiabatic holonomic gate acting in the
subspace of a three-level transmon fabricated in a fully coplanar design.
Experimentally, this is realized by simultaneously coupling the first two
transitions by microwave pulses with amplitudes and phases defined such that
the condition of parallel transport is fulfilled. We demonstrate the creation
of arbitrary superpositions in this subspace by changing the amplitudes of the
pulses and the relative phase between them. We use two-photon pulses acting in
the holonomic subspace to reveal the coherence of the state created by the
geometric gate pulses and to prepare different superposition states. We also
test the action of holonomic NOT and Hadamard gates on superpositions in the
subspace
ECMAScript -- The journey of a programming language from an idea to a standard
A significant portion of the web is powered by ECMAScript. As a web
technology, it is ubiquitous and available on most platforms natively or
through a web browser. ECMAScript is the dominant language of the web, but at
the same time, it was not designed as such. The story of ECMAScript is a story
of the impact of standardization on the popularity of technology.
Simultaneously, the story shows how external pressures can shape a programming
language and how politics can mar the evolution of a standard. In this article,
we will go through the movements that led to the dominant position of
ECMAScript, evaluate the factors leading to it, and consider its evolution
using the Futures Triangle framework and the theory of standards wars.Comment: 20 pages, 2 figures, 2 tables, EURAS 2023, preprint of an accepted
full pape
Factors predicting mortality in type 2 diabetes. With special reference to physical exercise, blood pressure, proteinuria, inflammation and P wave duration
Background: Type 2 diabetes patients have a 2-4 fold risk of cardiovascular disease (CVD) compared to the general population. In type 2 diabetes, several CVD risk factors have been identified, including obesity, hypertension, hyperglycemia, proteinuria, sedentary lifestyle and dyslipidemia. Although much of the excess CVD risk can be attributed to these risk factors, a significant proportion is still unknown.
Aims: To assess in middle-aged type 2 diabetic subjects the joint relations of several conventional and non-conventional CVD risk factors with respect to cardiovascular and total mortality.
Subjects and methods: This thesis is part of a large prospective, population based East-West type 2 diabetes study that was launched in 1982-1984. It includes 1,059 middle-aged (45-64 years old) participants. At baseline, a thorough clinical examination and laboratory measurements were performed and an ECG was recorded. The latest follow-up study was performed 18 years later in January 2001 (when the subjects were 63-81 years old). The study endpoints were total mortality and mortality due to CVD, coronary heart disease (CHD) and stroke.
Results: Physically more active patients had significantly reduced total, CVD and CHD mortality independent of high-sensitivity C-reactive protein (hs-CRP) levels unless proteinuria was present. Among physically active patients with a hs-CRP level >3 mg/L, the prognosis of CVD mortality was similar to patients with hs-CRP levels ≤3 mg/L. The worst prognosis was among physically inactive patients with hs-CRP levels >3 mg/L. Physically active patients with proteinuria had significantly increased total and CVD mortality by multivariate analyses. After adjustment for confounding factors, patients with proteinuria and a systolic BP <130 mmHg had a significant increase in total and CVD mortality compared to those with a systolic BP between 130 and 160 mmHg. The prognosis was similar in patients with a systolic BP <130 mmHg and ≥160 mmHg. Among patients without proteinuria, a systolic BP <130 mmHg was associated with a non-significant reduction in mortality. A P wave duration ≥114 ms was associated with a 2.5-fold increase in stroke mortality among patients with prevalent CHD or claudication. This finding persisted in multivariable analyses. Among patients with no comorbidities, there was no relationship between P wave duration and stroke mortality.
Conclusions: Physical activity reduces total and CVD mortality in patients with type 2 diabetes without proteinuria or with elevated levels of hs-CRP, suggesting that the anti-inflammatory effect of physical activity can counteract increased CVD morbidity and mortality associated with a high CRP level. In patients with proteinuria the protective effect was not, however, present. Among patients with proteinuria, systolic BP <130 mmHg may increase mortality due to CVD. These results demonstrate the importance of early intervention to prevent CVD and to control all-cause mortality among patients with type 2 diabetes. The presence of proteinuria should be taken into account when defining the target systolic BP level for prevention of CVD deaths. A prolongation of the duration of the P wave was associated with increased stroke mortality among high-risk patients with type 2 diabetes. P wave duration is easy to measure and merits further examination to evaluate its importance for estimation of the risk of stroke among patients with type 2 diabetes.Siirretty Doriast
Farmland birds and habitat heterogeneity in intensively cultivated boreal agricultural landscapes
The biodiversity of farmland ecosystems has decreased remarkably during the latter half of the 20th century, and this development is due to intensive farming with its various environmental effects. In the countries of the EU the Common Agricultural Policy (CAP) is the main determinant affecting farmland biodiversity, since the agricultural policy defines guidelines of agricultural practices. In addition to policies promoting intensive farming, CAP also includes national agri-environment schemes (AES), in which a part of subsidies paid to farmers is directed to acts that are presumed to promote environmental protection and biodiversity. In order to shape AES into relevant and powerful tools for biodiversity protection, detailed studies on the effects of agriculture on species and species assemblages are needed.
In my thesis I investigated the importance of habitat heterogeneity and effects of different habitat and landscape characteristics on farmland bird abundance and diversity in typical cereal cultivation-dominated southern Finnish agricultural environments. The extensive data used were collected by territory mapping. My two main study species were the drastically declined ortolan bunting (Emberiza hortulana) and the phenomenally increased tree sparrow (Passer montanus); in addition I studied assemblages of 20 species breeding in open arable and edge/bush habitats. In light of my results I discuss whether the Finnish AES take into account the habitat needs of farmland birds, and I provide suggestions for improvement of the future AES.
My results show that heterogeneity of both uncultivated and cultivated habitats increases abundance and species richness among farmland birds, but in this respect the amount and diversity of uncultivated habitats are essential. Ditches in particular are a keystone structure for farmland birds in boreal landscapes. Ditches lined by trees or bushes increased ortolan bunting abundance. Loss of that kind of ditches (and clearance of forest and bush patches), reduced breeding ortolan buntings, mainly by decreasing availability of song-posts that are important for the breeding groups of the species. Heterogeneity of uncultivated habitats, most importantly open ditches and the habitat patch richness, increased densities and species richnesses of species assemblages of open arable and edge/bush habitats. Human impact (winter-feeding, nest-boxes) affected favourably the tree sparrow s rapid range expansion in southern Finland, but any habitat types had no significant effects.
At the moment the Finnish agri-environmental policy does not conserve farmland ditches as a habitat type. Instead, sub-surface drainage is financially promoted. This is a fatal mistake as far as farmland biodiversity is concerned. In addition to the maintenance of ditches, at least the following aspects should be included more than is done previously in the measures of the future AES: 1) promotion of diverse crop rotation (especially by promoting animal husbandry), 2) maintenance of tree and bush vegetation in islets and along ditches, 3) promotion of organic farming.Maatalousympäristömme luonnon monimuotoisuus on tehomaatalouden myötä köyhtynyt huomattavasti viimeisen 50 vuoden aikana. Eurooppalaisen maatalousluonnon monimuotoisuuteen voimakkaimmin vaikuttava tekijä on EU-maiden yhteinen maatalouspolitiikka (YMP), joka asettaa suuntaviivat sille miten maataloutta harjoitetaan. Valtaosa YMP:n budjetista kohdistuu tuotannon tehostamiseen, mutta YMP:n sisältyvät myös kansalliset maatalouden ympäristöohjelmat (agri-environment schemes = AES), joissa osa viljelijöille maksettavista tukiaista suunnataan ympäristöä ja luonnon monimuotoisuutta suojeleviin toimenpiteisiin. Jotta AES:t voitaisiin tulevaisuudessa muokata mahdollisimman tehokkaiksi luonnon monimuotoisuutta ajatellen, tarvitaan tutkimusta maatalouden vaikutuksista eliölajeihin.
Väitöskirjassani olen tutkinut elinympäristöjen monimuotoisuuden merkitystä ja erilaisten yksittäisten elinympäristötyyppien vaikutuksia pesivän peltolinnuston runsauteen ja lajirikkauteen. Ajallisesti ja maantieteellisesti mittava aineisto kerättiin kartoituslaskentamenetelmää käyttäen Etelä-Suomesta, joissa kevätkylvöisten viljojen viljely on vallitseva viljelytyyppi. Päätutkimuslajini olivat voimakkaasti vähentynyt peltosirkku sekä voimakkaasti runsastunut pikkuvarpunen; lisäksi tutkin lintuyhteisöjä, jotka koostuivat 20 lajista, jotka pesivät avoimessa peltoympäristössä ja reuna- tai pusikko-elinympäristöissä. Tulosteni valossa tarkastelen sisältääkö Suomen AES toimenpiteitä, jotka ottavat huomioon peltolinnuston elinympäristövaatimukset. Lisäksi tarjoan parannusehdotuksia tulevaisuuden AES:a varten.
Tulokseni osoittavat että sekä viljelemättömien että viljeltyjen elinympäristöjen monimuotoisuus lisää peltolintujen runsautta ja lajirikkautta, ja ennen kaikkea viljelemättömien elinympäristöjen runsaus ja monipuolisuus on tärkeää. Ojat sekä avoimet että puiden tai pensaiden reunustamat tarjoavat suojaa, pesäpaikkoja ja ruokaa peltolinnuille ja ovat erityisen tärkeä elinympäristö peltoaukeillamme. Puiden ja pensaiden reunustamien ojien, sekä puu- ja pensassaarekkeiden, häviäminen peltomaisemasta vähensi peltosirkun runsautta, ennen kaikkea vähentämällä laulupaikkoja jotka ovat tärkeitä lajin pesimäryhmille. Avo-ojat lisäsivät lintuyhteisöjen runsautta ja lajirikkautta. Ihmisen vaikutuksella (talviruokinta, linnunpöntöt) oli myönteinen vaikutus pikkuvarpusen levinneisyysalueen laajenemiseen peltoympäristössä, kun taas erilaisilla elinympäristötyypeillä ei ollut siihen merkitsevää vaikutusta.
Tällä hetkellä suomalainen maatalouspolitiikka ei tue ojien säilyttämistä maatalousympäristössä. Päinvastoin, salaojitusta tuetaan rahallisesti, ilman että kunnollista tarkastelua ojien merkityksestä luonnon monimuotoisuudelle on tehty. Tämä on mielestäni väärä kehityssuunta, sillä omien ja aiemmin julkaistujen eurooppalaisten tutkimusten valossa ojien tärkeys on selvä. Sen lisäksi että ojien säilyttäminen sisällytettäisiin tulevaisuuden AES:n, ehdotan että seuraavia asioita tulisi jatkossa tukea enemmän kuin aiemmin on tehty: 1) monipuolinen viljelykierto (ennen kaikkea karjataloutta tukemalla), 2) puu- ja pensaselinympäristöjen säilyttäminen, 3) luomuviljely (tukee myös kohtaa 1)
Applications of dimensional reduction to electroweak and QCD matter
When heated to high temperatures, the behavior of matter changes dramatically. The standard model fields go through phase transitions, where the strongly interacting quarks and gluons are liberated from their confinement to hadrons, and the Higgs field condensate melts, restoring the electroweak symmetry. The theoretical framework for describing matter at these extreme conditions is thermal field theory, combining relativistic field theory and quantum statistical mechanics.
For static observables the physics is simplified at very high temperatures, and an effective three-dimensional theory can be used instead of the full four-dimensional one via a method called dimensional reduction. In this thesis dimensional reduction is applied to two distinct problems, the pressure of electroweak theory and the screening masses of mesonic operators in quantum chromodynamics (QCD). The introductory part contains a brief review of finite-temperature field theory, dimensional reduction and the central results, while the details of the computations are contained in the original research papers. The electroweak pressure is shown to converge well to a value slightly below the ideal gas result, whereas the pressure of the full standard model is dominated by the QCD pressure with worse convergence properties. For the mesonic screening masses a small positive perturbative correction is found, and the interpretation of dimensional reduction on the fermionic sector is discussed.Hyvin korkeassa lämpötilassa aineen ominaisuudet muuttuvat huomattavasti. Sen pienimpienkin rakenneosien väliset sidokset särkyvät, ja muodostuu alkeishiukkasista koostuva plasma, jonka käyttäytymisen ennustamiseen tarvitaan sähkömagnetismin lisäksi vahvan ja heikon ydinvuorovaikutuksen teorioita.
Erityisen mielenkiintoinen on vahvasti vuorovaikuttavassa aineessa korkeassa lämpötilassa tapahtuva olomuodon muutos, jonka seurauksena tavallisesti toisiinsa kahlittujen hiukkasten voidaan havaita käyttäytyvän riippumattomasti. Tällaista ainetta on vasta hiljattain onnistuttu tuottamaan hiukkaskiihdyttimissä. Vielä korkeammassa lämpötilassa myös heikosti vuorovaikuttavan aineen olomuoto muuttuu tilaan, jossa alkeishiukkasista tulee massattomia ja sähkömagneettinen ja heikko voima yhdistyvät. Riittävän korkeita lämpötiloja on luonnossa esiintynyt vain varhaisessa maailmankaikkeudessa, mutta sähköheikkojen vuorovaikutusten vaikutukset maailmankaikkeuden laajenemiseen voitaneen havaita tulevissa taustasäteilymittauksissa.
Kun lämpötila on erittäin korkea, voidaan ajasta riippumattomia suureita laskea käyttäen hyväksi alkuperäistä teoriaa yksinkertaisempaa, karkeistettua kolmiulotteista kenttäteoriaa. Tässä väitöstutkimuksessa menetelmää on sovellettu kahteen toisistaan riippumattomaan ongelmaan. Kuuman sähköheikon aineen paine, eräs tärkeimmistä lämpöopin suureista, on laskettu hyvin tarkasti ja yhdistetty aiemmin toisaalla laskettuun vahvan vuorovaikutuksen paineeseen, jolloin tunnetaan koko hiukkasfysiikan standardimallin paine korkeassa lämpötilassa. Lisäksi on tutkittu kuumassa ja tiheässä vahvasti vuorovaikuttavassa plasmassa mesonien varjostuspituuksia, jotka kuvaavat tasapainotilasta poikkeavien häiriöiden heikkenemistä plasmassa
Functional biodiversity in soils. Development and applicability of an enzyme activity pattern measurement method
Soil microorganisms mediate central reactions of element cycles in a heterogenic environment characterized by discontinuity of energy, nutrients, and water together with sharp pH gradients. They are diverse in species, numerous in quantity and possess a multitude of functions. One gram of soil may contain 10x109 microbial cells; for comparison, the Earth has only 7x109 human inhabitants. Species richness, evenness and composition in soils is impossible to measure, and therefore a convenient means of characterising soil microorganisms is to measure the type and rate of reactions occurring.The aim of this work was to develop a rapid, sensitive method to measure the activities of a set of soil enzymes simultaneously in a small scale. In the method, homogenized soil suspensions are investigated using fluorescent substrate analogues freeze-dried onto multiwall plates. It was shown that extraction of enzymes from soils produced inconsistent and unpredictable yields of the various activities and was therefore not applied as a pretreatment. Applicability of the method was evaluated by characterising soils treated with different agricultural practices, supporting a variety of crop plants and with fluctuating seasonal attributes. Bulk samples from experimental sites established both in agricultural and forest soils were utilized. Details of method development and of the effects of different treatments on enzyme activity pattern and on individual enzyme activities are discussed.The effects of eight crop plants, peat amendment and two consecutive sampling years yielded significant differences in soil extracellular enzyme activities. The effect of crop plants was most pronounced: eight of the measured ten activities yielded statistically significant differences in both years. The activities differed between years for six enzymes. The effect of peat was slight and was observed only two years after the addition. In another experiment, green or composted plant residues tended to enhance the activities of enzymes compared with chemical fertilizers, although the effect was not consistent. Forest soils usually yielded higher specific activities than field soils and the enzymes showed higher potential activities under alder than under pine. Temporal fluctuations of enzyme activities were also studied.Cluster analysis was utilized for data analysis in order to combine all measured attributes and to reveal the differences in the entire pattern, even though the differences in individual enzyme level were not statistically significant and the enzyme activities often correlated with each other.Due to the multitude of processes and functions, together with the wide taxonomic diversity in soils, method development in soil microbiology is still a major challenge. Interpretation of results usually requires a reference comparison. The method developed in the present study is proposed to be used as a sensitive measure of soil functional activity
Pressure of the Standard Model Near the Electroweak Phase Transition
We extend our previous determination of the thermodynamic pressure of the
Standard Model so that the result can be applied down to temperatures
corresponding to the electroweak crossover. This requires a further resummation
which can be cleanly organised within the effective theory framework. The
result allows for a precise determination of the expansion rate of the Universe
for temperatures around the electroweak crossover.Comment: 16 pages, 6 figures. v2: published versio
Responses to advice-seeking on Reddit that do not give advice
Previous studies have observed that asynchronous online interaction relies on sequence organization in the same way as spoken interaction, but that its sequential implicativeness might sometimes become looser. This means that advice-seeking may be followed by something other than advice, without it being treated as problematic. This study in-vestigates such instances on Reddit, utilizing the Conversation Analytic concepts of affiliative stance and action alignment. The analysis led to two major observations. First, based on the affiliative stance, there are three ways of reacting to an advice-seeking post: accepting, negotiating, and denying the validity of the advice-seeking. Second, most re-sponses that did not align with the action did align with the overall activity or another action made relevant by the preceding message. Based on the analysis, this article offers a system for classifying responses to advice-seeking that do not give advice. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe
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