Comparing real-time coupled cluster methods through simulation of collective Rabi oscillations

The time-dependent equation-of-motion coupled cluster (TD-EOM-CC) and time-dependent coupled cluster (TDCC) methods are compared by simulating Rabi oscillations for different numbers of non-interacting atoms in a classical electromagnetic field. While the TD-EOM-CC simulations are numerically stable, the oscillating time-dependent energy scales unreasonably with the number of subsystems resonant with the field. The TDCC simulations give the correct scaling of the time-dependent energy in the initial stages of the Rabi cycle, but the numerical solution breaks down when the multi-atom system approaches complete population inversion. We present a general theoretical framework in which the two methods can be described, where the cluster amplitude time derivatives are taken as auxiliary conditions, leading to a shifted time-dependent Hamiltonian matrix. In this framework, TDCC has a shifted Hamiltonian with a block upper triangular structure, explaining the correct scaling properties of the method.Comment: 9 pages and 4 figure

Coupled cluster simulation of impulsive stimulated X-ray Raman scattering

Time-dependent equation-of-motion coupled cluster (TD-EOM-CC) is used to simulate impulsive stimulated x-ray Raman scattering (ISXRS) of ultrashort laser pulses by neon, carbon monoxide, pyrrole, and p-aminophenol. The TD-EOM-CC equations are expressed in the basis of field-free EOM-CC states, where the calculation of the core-excited states is simplified through the use of the core-valence separation (CVS) approximation. The transfer of electronic population from the ground state to the core- and valence-excited states is calculated for different numbers of included core- and valence-excited states, as well as for electric field pulses with different polarizations and carrier frequencies. The results indicate that Gaussian pulses can transfer significant electronic populations to the valence states through the Raman process. The sensitivity of this population transfer to the model parameters is analyzed. The time-dependent electronic density for p-aminophenol is also showcased, supporting the interpretation that ISXRS involves localized core excitations and can be used to rapidly generate valence wavepackets.Comment: 10 pages, 5 figure

Information models properties in learning health systems : A literature review

publishedVersio

Monitoring Insulin Aggregation via Capillary Electrophoresis

Early stages of insulin aggregation, which involve the transient formation of oligomeric aggregates, are an important aspect in the progression of Type II diabetes and in the quality control of pharmaceutical insulin production. This study is the first to utilize capillary electrophoresis (CE) with ultraviolet (UV) detection to monitor insulin oligomer formation at pH 8.0 and physiological ionic strength. The lag time to formation of the first detected species in the aggregation process was evaluated by UV-CE and thioflavin T (ThT) binding for salt concentrations from 100 mM to 250 mM. UV-CE had a significantly shorter (5–8 h) lag time than ThT binding (15–19 h). In addition, the lag time to detection of the first aggregated species via UV-CE was unaffected by salt concentration, while a trend toward an increased lag time with increased salt concentration was observed with ThT binding. This result indicates that solution ionic strength impacts early stages of aggregation and β-sheet aggregate formation differently. To observe whether CE may be applied for the analysis of biological samples containing low insulin concentrations, the limit of detection using UV and laser induced fluorescence (LIF) detection modes was determined. The limit of detection using LIF-CE, 48.4 pM, was lower than the physiological insulin concentration, verifying the utility of this technique for monitoring biological samples. LIF-CE was subsequently used to analyze the time course for fluorescein isothiocyanate (FITC)-labeled insulin oligomer formation. This study is the first to report that the FITC label prevented incorporation of insulin into oligomers, cautioning against the use of this fluorescent label as a tag for following early stages of insulin aggregation

Secondary mineral formation associated with respiration of nontronite, NAu-1 by iron reducing bacteria

Experimental batch and miscible-flow cultures were studied in order to determine the mechanistic pathways of microbial Fe(III) respiration in ferruginous smectite clay, NAu-1. The primary purpose was to resolve if alteration of smectite and release of Fe precedes microbial respiration. Alteration of NAu-1, represented by the morphological and mineralogical changes, occurred regardless of the extent of microbial Fe(III) reduction in all of our experimental systems, including those that contained heat-killed bacteria and those in which O(2), rather than Fe(III), was the primary terminal electron acceptor. The solid alteration products observed under transmission electron microscopy included poorly crystalline smectite with diffuse electron diffraction signals, discrete grains of Fe-free amorphous aluminosilicate with increased Al/Si ratio, Fe-rich grains, and amorphous Si globules in the immediate vicinity of bacterial cells and extracellular polymeric substances. In reducing systems, Fe was also found as siderite. The small amount of Fe partitioned to the aqueous phase was primarily in the form of dissolved Fe(III) species even in the systems in which Fe(III) was the primary terminal electron acceptor for microbial respiration. From these observations, we conclude that microbial respiration of Fe(III) in our laboratory systems proceeded through the following: (1) alteration of NAu-1 and concurrent release of Fe(III) from the octahedral sheets of NAu-1; and (2) subsequent microbial respiration of Fe(III)

Unraveling the Early Events of Amyloid-β Protein (Aβ) Aggregation: Techniques for the Determination of Aβ Aggregate Size

The aggregation of proteins into insoluble amyloid fibrils coincides with the onset of numerous diseases. An array of techniques is available to study the different stages of the amyloid aggregation process. Recently, emphasis has been placed upon the analysis of oligomeric amyloid species, which have been hypothesized to play a key role in disease progression. This paper reviews techniques utilized to study aggregation of the amyloid-β protein (Aβ) associated with Alzheimer’s disease. In particular, the review focuses on techniques that provide information about the size or quantity of oligomeric Aβ species formed during the early stages of aggregation, including native-PAGE, SDS-PAGE, Western blotting, capillary electrophoresis, mass spectrometry, fluorescence correlation spectroscopy, light scattering, size exclusion chromatography, centrifugation, enzyme-linked immunosorbent assay, and dot blotting

The Palliative Radiotherapy and Inflammation Study (PRAIS) - protocol for a longitudinal observational multicenter study on patients with cancer induced bone pain

BackgroundRadiation therapy (RT) results in pain relief for about 6 of 10 patients with cancer induced bone pain (CIBP) caused by bone metastases. The high number of non-responders, the long median time from RT to pain response and the risk of adverse effects, makes it important to determine predictors of treatment response. Clinical features such as cancer type, performance status and pain intensity, and biomarkers for osteoclast activity are proposed as predictors of response to RT. However, results are inconsistent and there is a need for better predictors of RT response. A similar argument can be stated for the development of cachexia; there are currently no predictors that can identify patients who will develop cachexia later in the cancer disease trajectory. Experimental and preclinical studies show that pain, depression and cachexia are related to inflammation. However, it is not known if inflammatory biomarkers can predict CIBP, depression or development of cachexia.MethodsThis multicenter, multinational longitudinal observational study will include 600 adult patients receiving RT for CIBP. Demographic data, clinical variables, osteoclast and inflammatory biomarkers will be assessed before start of RT, and 3, 8, 16, 24 and 52 weeks after last course of RT. The primary aim of the study is to identify potential predictors for pain relief from RT. Secondary aims are to explore potential predictors for development of cachexia, the longitudinal relationship between pain intensity and depression, and if inflammatory biomarkers are associated with changes in pain intensity, cachexia and depression during one-year follow up.DiscussionThe immediate clinical implication of the PRAIS study is to identify potential predictive factors for a RT response on CIBP, and thereby reduce non-efficacious RT. Patient benefits are fewer hospital visits, reduced risk of adverse effects and more individualized pain treatment. The long-term clinical implication of the PRAIS study is to improve the knowledge about inflammation in relation to CIBP, cachexia and depression and potentially identify associations and mechanisms that can be targeted for treatment.Trial registrationClinicalTrials.gov NCT02107664, date of registration April 8, 2014 (retrospectively registered).Trial sponsorThe European Palliative Care Research Centre (PRC), Department of Clinical and Molecular Medicine, NTNU, Faculty of medicine and Health Sciences, Trondheim, N-7491, Norway

Modeling interactions between hydrogen-like atoms and intense laser pulses with the Dirac equation

In this thesis, a model to describe the interactions between hydrogen-like atoms and intense laser pulses using the Dirac equation is developed. The modeling of these interactions can be motivated by the advances in laser technology through the last decades, which have increased the peak intensities of laser pulses by many orders of magnitude. Improved understanding of how the pulses from the new lasers affect hydrogen-like atoms might transmit to improved understanding of, and control over, various states of matter exposed to intense electromagnetic radiation. The Dirac equation for the isolated hydrogen-like atom, before interacting with the laser pulse, was solved numerically through the expansion of the solution in both the dual kinetic balance basis set and in the ideal basis set. Both basis sets were based on B-splines. The ideal basis set was chosen as the preferred one, since the solutions from the dual kinetic basis set displayed an oscillatory behavior at the boundary of the domain. A small relativistic shift in the bound states and in the positive continuum was identified. The interaction matrix between the hydrogen-like atom and the laser pulse was then calculated by expanding the time dependent solution of the system in the eigenstates of the hydrogen-like atom. This was done both in the dipole approximation, and in an approximation that goes beyond the dipole approximation. The effect of the interaction with the laser pulse was calculated for both laser pulse approximations using a short-time propagator with the Lanczos algorithm. The total and energy differential photoionization probabilities were then calculated, and compared with results from the Schrödinger equation with and without relativistic corrections. A relativistic shift in both the total photoionization probability and in the locations of the peaks in the energy differential probability plot for the dipole approximation was identified. The transmission to the negative energy continuum states during the time of propagation was shown to be the primary cause of the relativistic effects in the model

"Stoler vi på dem?" : en studie av politisk tillit i lokalt perspektiv cAudun Skeidsvoll

"STOLER VI PÅ DEM?" EN STUDIE AV POLITISK TILLIT I LOKALT PERSPEKTIV. Oppgavens empiriske grunnlag er hovedsakelig en større landsomfattende survey-undersøkelse gjennomført i 1993. "Brukere, Betalere, Borgere"-prosjektets formål er å belyse den enkeltes rolle som samfunnsmedlem, og da spesielt i forhold til kommunen og kommunalpolitikk i dagens Norge. Oppgaven er en kvantitativ analyse som drar nytte av bivariat, multivariat og kausal tilnærming til påvirkningsforholdet mellom uavhengige variable på den avhengige -- pluss en dimensjonsanalyse av tillitsbegrepet. Den avhengige variabel er lokal politisk tillit. I statsvitenskapelig sammenheng er mye arbeid lagt ned i analyser av politisk tillit på nasjonalt eller transnasjonalt styringsnivå. Innsatsen på subnasjonalt styringsnivå har derimot vært langt mindre. Oppgaven er et forsøk på å avdekke om kjennetegn ved enkeltindivid og lokalsamfunn påvirker holdningene til lokalpolitikerne. For det første bekrefter analysen at politisk betinget misnøye spiller en sentral rolle for utviklingen av positive/negative holdninger til lokalpolitikerne -- i likhet med funn på nasjonalt styringsnivå. Også enkeltmenneskets personlige egenskaper (politisk kompetanse/interesse) og sider ved bostedskommunen slår ut på den lokale politikertillit. Derimot spiller sosiale bakgrunnsforhold -- deriblant oppvekstvilkår -- en mer beskjeden rolle for den lokale politiske tillit og i en viss utstrekning kun indirekte gjennom personlige egenskaper. Av de sosiale bakgrunnsmål varierer først og fremst tillit til lokale folkevalgte i forhold til det en kan definere som ressursmål: Husholdnings inntekt, utdanning og politisk aktive i familien i oppveksten. Det er ingen tendens til at kvinner har mindre tillit til lokale politikere enn menn. Forøvrig avdekker analysen også effekt av alder. De eldre har i større grad enn yngre tillit til lokale politikere -- dessuten tyder funn på at antall respondenten som gir uttrykk for "ekstremverdier" på den lokalpolitiske tillitsindeksen øker med økende alder. Alt i alt bekrefter analysen av sosiale bakgrunnsmål det lite kontroversielle funn at sosiale ressurser teller -- regnet både i fortid og nåtid. Et annet viktig funn er en påvisning av flere skinnsammenhenger. Sterkest peker enkelte av målene blant de sosiale bakgrunnsforhold og mål inkludert i den lokale kontekst seg ut. De sosiale bakgrunnsmålene inntekt, utdanning, politisk aktive og sosioøkonomisk status reduseres ved introduksjon av målene inkludert i forklaringsperspektivet personlige egenskaper. Flere tidligere studier på nasjonalt styringsnivå peker på en lignende sammenheng mellom sosiale bakgrunnsmål og personlige egenskaper. Selv om også denne studien avdekker flere indirekte påvirkningsforhold er det viktig å påpeke at flere av de sosiale bakgrunnsforholdene også avdekker relativt sterke direkte effekter på den avhengige (f.eks. alder og yrkessektor). Uansett -- analysen avdekker at flertallet av de sosiale bakgrunnsmålene taper effekt etter kontroll for mellomliggende variable på den avhengige. En mulig substansiell tolkning er at en del av de ressurssvake gruppenes manglende tillit kan forklares med at de finner den lokale politikk komplisert og at de mangler kunnskap om det lokale forvaltningsnivå. En annen tolkning er at økende sosial status gir selvtillit, eventuelt at utdanning gir kunnskaper og innsikt som er viktig for tro på egen kompetanse -- og dermed indirekte påvirker den politiske tillit. Tidligere funn på nasjonalt styringsnivå som viser til at inntekt og utdanning spiller en viktig rolle for egen politisk kompetanse -- og dermed den politiske tillit -- ser ut til å holde stikk også på lokalt styringsnivå (Converse 1972; Martinussen 1977) Avslutningsvis spesifiseres at deler av effekten av kommunestørrelse på lokal politisk tillit egentlig er uttrykk for god tilgjengelighet i små kommuner. Interessant, men ikke overraskende avdekkes også at påvirkningsforholdet mellom kommuneøkonomi og tillit til lokalpolitikerne preges av at respondenten i velstående kommuner er bedre fornøyd med det kommunale tjenestetilbud enn respondenten i mindre velstående kommuner. Men først og fremst bekreftes at kommunestørrelse og kommuneøkonomi på tross av kontroll for mellomliggende mål har genuin direkte påvirkning på den lokale politiske tillit I et kortfattet sammendrag passer det godt å avslutte med et funn som indirekte indikerer at kommunen nok i stor grad oppfattes som en serviceinstitusjon av innbyggerne. Tilfredshet/utilfredshet med tjenestetilbud og tilgjengelighet (politisk betinget misnøye) er hver for seg og tilsammen de faktorer som i størst grad forklarer eventuell variasjon i politisk tillit på lokalt styringsnivå i dagens Norge. Når ikke servicefunksjonene er på plass lar vi det gå ut over politikerne -- vi taper tillit