253 research outputs found
Estimating nonresponse bias and mode effects in a mixed mode survey
In mixed-mode surveys, it is difficult to separate sample selection differences from mode-effects that can occur when respondents respond in different interview settings. This paper provides a framework for separating mode-effects from selection effects by matching very similar respondents from different survey modes using propensity score matching. The answer patterns of the matched respondents are subsequently compared. We show that matching can explain differences in nonresponse and coverage in two Internet-samples. When we repeat this procedure for a telephone and Internet-sample however, differences persist between the samples after matching. This indicates the occurrence of mode-effects in telephone and Internet surveys. Mode-effects can be problematic; hence we conclude with a discussion of designs that can be used to explicitly study mode-effects
Emulating interviewers in an online survey: Experimental manipulation of 'do-not-know' over the phone and on the web.
[Dataset available: http://hdl.handle.net/10411/17676]
Mode effect or question wording? Measurement error in mixed mode surveys.
[Dataset available: http://hdl.handle.net/10411/17672]
Stability of scale quality under various data collection procedures: A mode comparison on the 'de Jong Gierveld Loneliness Scale'
Emulating interviewers in an online survey:Experimental manipulation of 'do-not-know' over the phone and on the web
Considerazioni sulla necessita di un approccio integrato tra medicina veterinaria e medicina umana nelle strategie di prevenzione della West Nile Disease in Regione Toscana.
La West Nile Disease (WND) Ăš una zoonosi causata dal West Nile Virus (WNV), un Arbovirus neuropatogeno trasmesso principalmente da zanzare ornitofile isolato per la prima volta in Uganda nel 1937 e responsabile di meningo-encefalite nell'uomo e negli equidi. Il primo focolaio italiano di WND si Ăš manifestato in Regione Toscana nel 1998 nell'area lacustre del Padule di Fucecchio nella quale si verificarono casi clinici in 14 cavalli, 6 dei quali con esito mortale, ma senza interessare l'uomo. A distanza di 10 anni dalla prima notifica, nell'agosto 2008, la WND Ăš ricomparsa in Italia nell'area del delta del Po ma, al contrario di quanto avvenne in Toscana, l'infezione del 2008 ha causato sintomatologia clinica, oltre che nei cavalli, anche in 8 persone. Nel 2009 l'infezione si Ăš ripresentata di nuovo in Regione Toscana con 10 cavalli risultati positivi al WNV confinati nella Provincia di Arezzo: sempre nel 2009, nell'area del delta del Po si verificarono 18 casi clinici nell'uomo 4 dei quali con esito mortale.
A fronte della diffusione del virus e del cambiamento della situazione epidemiologica nel territorio toscano, si rende necessaria un'analisi delle azioni di controllo che si stanno attuando da alcuni anni, sia in medicina veterinaria che umana, per ridefinire in maniera integrata le strategie di controllo nei confronti di questa malattia (e anche di altre zoonosi) in una prospettiva âOne Healthâ. Tale esigenza nasce dalla necessitĂ di superare il concetto di malattia âesoticaâ perchĂ©, a fronte dell'aumento della popolazione umana, della globalizzazione, degli scambi commerciali e dei cambiamenti climatici, malattie come la WND, oggi âesoticheâ non lo sono piĂč. In un mondo ormai sempre piĂč globalizzato nelle sue manifestazioni, nessuna singola disciplina o settore della societĂ ha conoscenze o risorse sufficienti per affrontare da sola i problemi legati alla salute delle persone e degli animali od allâintegritĂ degli ecosistemi. L''iniziativa âOne Medicine â One Healthâ, termine coniato dal medico veterinario e parassitologo Calvin W. Schwabe (1927â2006), Ăš una cornice logica che promuove la collaborazione tra diverse discipline affinchĂ© lavorino insieme stabilendo un approccio integrato (olistico) alla prevenzione della salute.
Partendo dai dati fruibili dagli attuali sistemi informativi, l'obiettivo del presente lavoro Ăš stato quello di illustrare considerazioni su vari aspetti relativi alla gestione della WND sia in campo umano che veterinario con l'intento di fornire spunti di riflessione per la costruzione di un sistema di sorveglianza integrato e, sopratutto, interattivo nello scambio delle informazioni in modo tale da essere in grado non solo di individuare tempestivamente la circolazione virale ma sopratutto di prevenire lo stato di malattia nell'uomo e negli animali. In tal senso, la collaborazione tecnico-scientifica tra medico-chirurgo, medico veterinario e altre professioni coinvolte, rappresenta un punto cardine sul quale lavorare per cercare di migliorare significativamente la salute umana e animale
A review of conceptual approaches and empirical evidence on probability and nonprobability sample survey research
There is an ongoing debate in the survey research literature about whether and when probability and nonprobability sample surveys produce accurate estimates of a larger population. Statistical theory provides a justification for confidence in probability sampling as a function of the survey design, whereas inferences based on nonprobability sampling are entirely dependent on models for validity. This article reviews the current debate about probability and nonprobability sample surveys. We describe the conditions under which nonprobability sample surveys may provide accurate results in theory and discuss empirical evidence on which types of samples produce the highest accuracy in practice. From these theoretical and empirical considerations, we derive best-practice recommendations and outline paths for future research
Comprehensive diagnostics of acute myeloid leukemia by whole transcriptome RNA sequencing
Acute myeloid leukemia (AML) is caused by genetic aberrations that also govern the prognosis of patients and guide risk-adapted and targeted therapy. Genetic aberrations in AML are structurally diverse and currently detected by different diagnostic assays. This study sought to establish whole transcriptome RNA sequencing as single, comprehensive, and flexible platform for AML diagnostics. We developed HAMLET (Human AML Expedited Transcriptomics) as bioinformatics pipeline for simultaneous detection of fusion genes, small variants, tandem duplications, and gene expression with all information assembled in an annotated, user-friendly output file. Whole transcriptome RNA sequencing was performed on 100 AML cases and HAMLET results were validated by reference assays and targeted resequencing. The data showed that HAMLET accurately detected all fusion genes and overexpression of EVI1 irrespective of 3q26 aberrations. In addition, small variants in 13 genes that are often mutated in AML were called with 99.2% sensitivity and 100% specificity, and tandem duplications in FLT3 and KMT2A were detected by a novel algorithm based on soft-clipped reads with 100% sensitivity and 97.1% specificity. In conclusion, HAMLET has the potential to provide accurate comprehensive diagnostic information relevant for AML classification, risk assessment and targeted therapy on a single technology platform
Evidence for the charge asymmetry in pp â ttÂŻ production at sâ = 13 TeV with the ATLAS detector
Inclusive and differential measurements of the topâantitop (ttÂŻ) charge asymmetry AttÂŻC and the leptonic asymmetry AââÂŻC are presented in protonâproton collisions at sâ = 13 TeV recorded by the ATLAS experiment at the CERN Large Hadron Collider. The measurement uses the complete Run 2 dataset, corresponding to an integrated luminosity of 139 fbâ1, combines data in the single-lepton and dilepton channels, and employs reconstruction techniques adapted to both the resolved and boosted topologies. A Bayesian unfolding procedure is performed to correct for detector resolution and acceptance effects. The combined inclusive ttÂŻ
charge asymmetry is measured to be Att¯C = 0.0068 ± 0.0015, which differs from zero by 4.7 standard deviations. Differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the tt¯ system. Both the inclusive and differential measurements are found to be compatible with the Standard Model predictions, at next-to-next-to-leading order in quantum chromodynamics perturbation theory with next-to-leading-order electroweak corrections. The measurements are interpreted in the framework of the Standard Model effective field theory, placing competitive bounds on several Wilson coefficients
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