47 research outputs found
The Expression Problem Revisited — Four new solutions using generics
No full textAbstract. The expression problem (aka the extensibility problem) refers to a fundamental dilemma of programming: To which degree can your application be structured in such a way that both the data model and the set of virtual operations over it can be extended without the need to modify existing code, without the need for code repetition and without runtime type errors. Over the years, many approaches to this problem have been proposed, each having different characteristics of type safety and reusability. While many of these rely on exotic or problem specific language extensions, this paper investigates the solution space within the framework of the soonto-be mainstream generic extensions of C # and the Java programming language. Four new solutions are presented which, though quite different, all rely on techniques that can be used in everyday programming.
The Tale of Two research Communities: The Diffusion of Research on Productive Efficiency
No full textThe field of theoretical and applied efficiency analysis is pursued both by economists and people from operational research and management science. Each group tends to cite a different paper as the seminal one. Recent availability of extensive electronically accessible databases of journal articles makes studies of the diffusion of papers through citations possible. Research strands inspired by the seminal paper within economics are identified and followed by citation analysis during the 20 year period before the operations research paper was published. The first decade of the operations research paper is studied in a similar way and emerging differences in diffusion patterns are pointed out. Main factors influencing citations apart from the quality of the research contribution are reputation of journal, reputation of author, number of close followers; colleagues, “cadres of protégés”, Ph.D. students, and extent of network (“invisible college”). Such factors are revealed by the citing papers. In spite of increasing cross contacts between economics and operations research the last decades co-citation analysis reveals a relative constant tendency to stick to “own camp” references.Farrell efficiency measures, data envelopment analysis, DEA, bibliometry
Comparing physiologically relevant corrosion performances of Mg AZ31 alloy protected by ALD and sputter coated TiO2
No full textThe utilization of Mg alloys for biomedical applications is so far underexplored due to the accelerated corrosion hampering patient recovery post implantation. Here, we explore the effectiveness of corrosion reduction of an AZ31 alloy in Simulated Body Fluid when coated with a 40 nm sputtered TiO2 layer and compare it to a similar coating made by Atomic Layer Deposition (ALD). Potentiodynamic polarization and hydrogen evolution experiments were performed on coated samples having different surface roughness and 3D topologies. Interestingly, ALD layers reduce corrosion current density by 94% on Ra = 118.6 ± 5.1 nm and 93% on Ra = 4794.3 ± 49.4 nm, whereas sputtered only by 84% on Ra = 118.6 ± 5.1 nm and 60% on Ra = 4794.3 ± 49.4 nm. Particularly on 3D aspects, the ALD coatings are superior, where a scaffold of 85% porosity with 1 mm pore sizes released 68% lower hydrogen compared to the sputtered counterparts. We relate these observations to the higher surface integrity, adhesion strength and lower line-of-sight restrictions of ALD compared to sputter deposition. The results can be interesting for researchers and practitioners aiming to make Mg alloys more commonplace as temporary metallic implant materials. © 2020 The Author
Arthur O. and Selma ?Sally? Eide Knold Letters, 1940
No full textThis collection contains letters mostly between Arthur and Sally, though there are a handful of letters to other people. The collection is in date order by the postmark on the envelopes. Many of the letters are written Hotel Fargoan stationary. These letters were used to write the three-book series, Hotel Fargoan by Eileen Torgersen-Smith
ADHD in adults; comorbidity and long-term central stimulant treatment: A retrospective, naturalistic study
No full textADHD hos voksne; samsykelighet og behandling med sentralstimulerende legemidler
ADHD er en tilstand som oppstår i barndommen og preges av hyperaktivitet, impulsivitet og oppmerksomhetssvikt. Symptomene på ADHD vedvarer inn i voksen alder hos mange pasienter, og er forbundet med funksjonssvikt på områder som utdannelse og arbeidsliv. Forekomst av andre psykiske lidelser samtidig (samsykelighet) er stor gjennom hele livsløpet. Sentralstimulerende legemidler (SSL) er godt dokumentert behandling av symptomene ved ADHD. Til tross for god symptomatisk effekt slutter mange pasienter tidlig med behandlingen, og mye er uavklart når det gjelder hvordan SSL behandling fungerer i vanlig klinisk praksis hos voksne.
Vi ønsket å beskrive forekomst av samsykelighet og funksjonssvikt hos voksne pasienter med ADHD. Videre ønsket vi å se på behandlingsforløp og identifisere variabler som predikerte behandlingsvarighet > 3 år. Det tredje målet med studien var å undersøke forekomsten av rusmisbruk i løpet av behandlingsforløpet og identifisere variabler knyttet til eventuelt misbruk. Vi ønsket også å identifisere kliniske og behandlingsmessige variabler relatert til yrkesmessig fungering i voksen alder.
Dette er en retrospektiv, naturalistisk studie på 3 utvalg av voksne pasienter med diagnosen ADHD. Den primære utredningen av pasientene ble gjort i henhold til prosedyrer bestemt av de Sakkyndige team for hyperkinetisk forstyrrelse i perioden 1997-2005. Hovedmengden av data til studien ble retrospektivt hentet fra den psykiatriske journalen. I Paper IV brukte vi i tillegg et spørreskjema.
Vi fant at voksne med ADHD hadde lavere utdanningsnivå og yrkesdeltagelse enn den generelle befolkningen. Mange pasienter hadde samsykelighet som rusmisbruk og personlighetsforstyrrelse. Til tross for de høye nivåene av samsykelighet og funksjonssvikt fikk de fleste pasientene behandling med SSL i lang tid (median varighet var 33 måneder). Behandlingsvarighet mer enn 3 år ble positivt predikert av om pasienten brukte langtidsvirkende SSL, og negativt predikert av om pasienten hadde personlighetsforstyrrelse. Hos pasienter uten tidligere rusmisbruk fant vi at behandling med SSL ikke førte til rusmisbruk. Pasienter som tidligere hadde hatt rusmisbruk hadde ikke høyere tilbakefall enn i grupper av voksne pasienter med rusmisbruk alene. Høy alder ved første SSL behandling og høyere grad av oppmerksomhetssvikt var assosiert med redusert yrkesdeltagelse i voksen alder.
Avhandlingen understreker det høye nivået av samsykelighet og funksjonssvikt ved ADHD hos voksne. Det viser seg allikevel mulig å behandle pasientene med SSL over lang tid, men det må undersøkes nærmere hvordan behandlingen skal gjennomføres hos pasienter med stor samsykelighet. En lengre periode med rusfrihet før SSL behandling kan redusere risiko for tilbakefall, men dette må undersøkes med kontrollerte studier. Studien antyder at tidlig behandling av ADHD er relatert til bedre yrkesmessig fungering i voksen alder, men i likhet med andre naturalistiske studier er det store metodologiske begrensninger. Vitenskapelig mer robuste studier bør gjøres for å undersøke effekten av SSL behandling av barn og unge på funksjonsnivå og samsykelighet i voksen alder.Background: Attention Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental condition of childhood onset characterised by hyperactivity, impulsivity and attention deficit. The condition persists into adulthood in a significant number of patients, and is clinically heterogeneous in terms of symptoms, comorbidity, functional impairment and clinical course. There is a considerable presence of comorbid psychiatric disorders throughout the lifespan. ADHD in adults is associated with poor functional outcome in important life domains like educational and occupational achievement. Research indicates that especially substance use disorders (SUD) and antisocial personality disorder (ASPD) are linked to adult ADHD. Central stimulant (CS) drugs are considered to be the cornerstone of pharmacological treatment in ADHD. Several clinically important effectiveness variables were understudied when the present studies started; like continuity of CS treatment in ordinary clinical practice, predictors for continuity and reasons for discontinuation of CS treatment, and the impact of comorbid disorders on aspects of CS treatment.
Objectives: The first main objective was to describe psychiatric comorbidity and functional impairment in 3 samples of clinical adult ADHD patients. The second objective was to to investigate CS treatment in a sample of adult ADHD and identify variables predicting longterm (> 3 years) CS treatment. The third objective was to investigate the prevalence of SUD during long-term CS treatment in a sample of adult ADHD and identify variables associated with SUD during treatment, and the fourth was to identify variables predicting occupational outcome in adult ADHD.
Methods: The present study is based on a retrospective, naturalistic design of 3 samples of adults diagnosed with ADHD in North-Trøndelag County in the period 1997 to 2009. The primary assessment of the patients was done according to procedures published by Expert Committees of Hyperkinetic Disorders/ADHD, as part of ordinary hospital routines. In a second step a report with all information gathered in the first step was sent to the Expert Committee of Hyperkinetic Disorders/ADHD for a definitive recommendation. The majority of data for the present study was retrospectively collected from the medical records by an experienced psychiatrist (the author). Paper IV additionally includes a cross-sectional questionnaire. The main measures were sociodemographic variables, baseline psychiatric comorbidity and the prevalence of SUD during long-term CS treatment, duration of abstinence from SUD before CS treatment started, and several CS treatment variables.
Results: We found that Norwegian adults with ADHD had far lower levels of education and employment compared to the general population, and the patients had high levels of psychiatric comorbidity like SUD and ASPD. Despite the high levels of comorbidity and functional impairment most adults with ADHD received CS treatment for several years (mean duration was 33 months). Treatment duration for more than 3 years was predicted positively by the use of extended release (ER) formulations of methylphenidate (MPH), and negatively by comorbid ASPD. In adult ADHD patients without previous comorbid SUD we found that CS treatment did not precipitate new onset of SUD. In patients with previous SUD the relapse rate during CS treatment was not higher than in adult patients with SUD alone. We also found that later age of first CS treatment and higher inattentiveness ratings were associated with lower level of employment in adulthood.
Conclusions: The present thesis emphasizes the high rates of comorbidity between adult ADHD and other psychiatric disorders like SUD and ASPD. In addition to a further emphasis on the impact of comorbidity on the course of ADHD future research should explore the functional impairment following ADHD in all ages, and identify treatment which is capable of reducing impairment. Further research should also focus on the treatment providing systems and investigate factors that could enhance CS treatment effectiveness such as compliance. A longer period of abstinence from SUD before CS treatment may reduce the risk for relapse. However, trial derived evidence is lacking and it needs to be examined in a study with a prospective, controlled design. Early treatment of ADHD is shown in the present and some other long-term studies to be related to better adult functioning. However, most long-term studies are open-label extensions or naturalistic studies, with several methodological limitations. Efforts should be made to initiate larger, scientifically more stringent and multisite naturalistic studies to investigate the impact of different treatments on adult functional outcomes.PhD i klinisk medisinPhD in Clinical Medicin
Unifying Genericity: Combining the Benefits of Virtual Types and Parameterized Classes
No full text. Generic types in programming languages are most often supported with various forms of parametric polymorphism, i.e. functions on types. Within the framework of object-oriented languages, virtual types present an alternative where specic types are derived from generic ones using inheritance rather than function application. While both mechanisms are statically safe and support basic genericity, they have very dierent typing properties, each of them providing for the description of useful relationships, which are not expressible with the other. In this paper we present, through the use of examples, a mechanism for describing generic classes: structural virtual types. This mechanism is essentially a merger of parameterized classes and virtual types and includes the bene ts of both, in particular retaining mutual recursion and covariance of virtual types as well as the function-like nature of parameterized classes. 1 Introduction The term genericity in our use covers the ..
