151 research outputs found
The impact of COVID-19 on research
This article is made available for unrestricted research re-use and secondary analysis in any form or be any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Coronavirus disease 2019 (COVID-19) has swept across the globe causing hundreds of thousands of deaths, shutting down economies, closing borders and wreaking havoc on an unprecedented scale. It has strained healthcare services and personnel to the brink in many regions and will certainly deeply mark medical research both in the short and long-term
Background due to stored electrons following nuclear decays in the KATRIN spectrometers and its impact on the neutrino mass sensitivity
The KATRIN experiment is designed to measure the absolute neutrino mass scale
with a sensitivity of 200 meV at 90% C.L. by high resolution tritium
beta-spectroscopy. A low background level of 10 mHz at the beta-decay endpoint
is required in order to achieve the design sensitivity. In this paper we
discuss a novel background source arising from magnetically trapped keV
electrons in electrostatic retarding spectrometers. The main sources of these
electrons are alpha-decays of the radon isotopes (219,220)Rn as well as
beta-decays of tritium in the volume of the spectrometers. We characterize the
expected background signal by extensive MC simulations and investigate the
impact on the KATRIN neutrino mass sensitivity. From these results we refine
design parameters for the spectrometer vacuum system and propose active
background reduction methods to meet the stringent design limits for the
overall background rate
Intakes of culinary herbs and spices from a food frequency questionnaire evaluated against 28-days estimated records
<p>Abstract</p> <p>Background</p> <p>Worldwide, herbs and spices are much used food flavourings. However, little data exist regarding actual dietary intake of culinary herbs and spices. We developed a food frequency questionnaire (FFQ) for the assessment of habitual diet the preceding year, with focus on phytochemical rich food, including herbs and spices. The aim of the present study was to evaluate the intakes of herbs and spices from the FFQ with estimates of intake from another dietary assessment method. Thus we compared the intake estimates from the FFQ with 28 days of estimated records of herb and spice consumption as a reference method.</p> <p>Methods</p> <p>The evaluation study was conducted among 146 free living adults, who filled in the FFQ and 2-4 weeks later carried out 28 days recording of herb and spice consumption. The FFQ included a section with questions about 27 individual culinary herbs and spices, while the records were open ended records for recording of herbs and spice consumption exclusively.</p> <p>Results</p> <p>Our study showed that the FFQ obtained slightly higher estimates of total intake of herbs and spices than the total intake assessed by the Herbs and Spice Records (HSR). The correlation between the two assessment methods with regard to total intake was good (r = 0.5), and the cross-classification suggests that the FFQ may be used to classify subjects according to total herb and spice intake. For the 8 most frequently consumed individual herbs and spices, the FFQ obtained good estimates of median frequency of intake for 2 herbs/spices, while good estimates of portion sizes were obtained for 4 out of 8 herbs/spices.</p> <p>Conclusions</p> <p>Our results suggested that the FFQ was able to give good estimates of frequency of intake and portion sizes on group level for several of the most frequently used herbs and spices. The FFQ was only able to fairly rank subjects according to frequency of intake of the 8 most frequently consumed herbs and spices. Other studies are warranted to further explore the intakes of culinary spices and herbs.</p
How to more effectively determine what is true: The limits of intuition
The plethora of scientific data and explosion of published materials often leave it challenging to develop a clear and concise overview of many scientific topics. A number of factors may contribute to our misunderstanding. It is the focus of this article to describe primary reasons for failure to establish a clear, factual and functional understanding regarding scientific areas of inquiry
The battle between fake news and science
Fake news is fabricated information that mimics news media content yet lacks the editorial norms and processes that ensure accuracy and credibility [ [1] ]. This includes misinformation (misleading information) and disinformation (false information purposely spread to deceive people)
Manual versus automatic bladder wall thickness measurements: a method comparison study
Purpose
To compare repeatability and agreement of conventional ultrasound bladder wall thickness (BWT) measurements with automatically obtained BWT measurements by the BVM 6500 device.
Methods
Adult patients with lower urinary tract symptoms, urinary incontinence, or postvoid residual urine were urodynamically assessed. During two subsequent cystometry sessions the infusion pump was temporarily stopped at 150 and 250 ml bladder filling to measure BWT with conventional ultrasound and the BVM 6500 device. For each method and each bladder filling, repeatability and variation was assessed by the method of Bland and Altman.
Results
Fifty unselected patients (30 men, 20 women) aged 21â86 years (median 62.5 years) were prospectively evaluated. Invalid BWT measurements were encountered in 2.1â14% of patients when using the BVM 6500 versus 0% with conventional ultrasound (significant only during the second measurement at 150 ml bladder filling). Mean difference in BWT values between the measurements of one technique was -0.1 to +0.01 mm. Measurement variation between replicate measurements was smaller for conventional ultrasound and the smallest for 250 ml bladder filling. Mean difference between the two techniques was 0.11â0.23 mm and did not differ significantly. The BVM 6500 device was not able to correctly measure BWTs above 4 mm.
Conclusions
Both BWT measurements are repeatable and agree with each other. However, conventional ultrasound measurements have a smaller measurement variance, can measure BWT in all patients, and BWTs above 4 mm
Linkage study of 14 candidate genes and loci in four large Dutch families with vesico-ureteral reflux
Vesico-ureteral reflux (VUR) is a major contributing factor to end-stage renal disease in paediatric patients. Primary VUR is a familial disorder, but little is known about its genetic causes. To investigate the involvement of 12 functional candidate genes and two reported loci in VUR, we performed a linkage study in four large, Dutch, multi-generational families with multiple affected individuals. We were unable to detect linkage to any of the genes and loci and could exclude the GDNF, RET, SLIT2, SPRY1, PAX2, AGTR2, UPK1A and UPK3A genes and the 1p13 and 20p13 loci from linkage to VUR. Our results provide further evidence that there appears to be genetic heterogeneity in VUR
Search for R-parity violating supersymmetry via the LLE couplings lambda_{121}, lambda_{122} or lambda_{133} in ppbar collisions at sqrt(s)=1.96 TeV
A search for gaugino pair production with a trilepton signature in the
framework of R-parity violating supersymmetry via the couplings lambda_121,
lambda_122, or lambda_133 is presented. The data, corresponding to an
integrated luminosity of L~360/pb, were collected from April 2002 to August
2004 with the D0 detector at the Fermilab Tevatron Collider, at a
center-of-mass energy of sqrt(s)=1.96 TeV. This analysis considers final states
with three charged leptons with the flavor combinations eel, mumul, and eetau
(l=e or mu). No evidence for supersymmetry is found and limits at the 95%
confidence level are set on the gaugino pair production cross section and lower
bounds on the masses of the lightest neutralino and chargino are derived in two
supersymmetric models.Comment: 9 pages, 4 figures (fig2 includes 3 subfigures
Measurement of the ppbar to ttbar production cross section at sqrt(s)=1.96 TeV in the fully hadronic decay channel
A measurement of the top quark pair production cross section in proton
anti-proton collisions at an interaction energy of sqrt(s)=1.96 TeV is
presented. This analysis uses 405 pb-1 of data collected with the D0 detector
at the Fermilab Tevatron Collider. Fully hadronic ttbar decays with final
states of six or more jets are separated from the multijet background using
secondary vertex tagging and a neural network. The ttbar cross section is
measured as sigma(ttbar)=4.5 -1.9 +2.0 (stat) -1.1 +1.4 (syst) +/- 0.3 (lumi)
pb for a top quark mass of m(t) = 175 GeV/c^2.Comment: 10 pages, 10 figures, submitted to Phys. Rev.
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