732 research outputs found
Warmte-koude opslag en duurzaam gebruik van de ondergrond
Warmte koude opslag (WKO) is een energie en kostenbesparende methode voor het verwarmen en koelen van gebouwen. Open WKO systemen pompen het grondwater heen en weer om het gebouw te koelen of te verwarmen. Gesloten WKO systemen gebruiken alleen de warmte van het grondwater om huizen te verwarmen of te koelen. In Nederland is er de laatste jaren een sterke en door de overheid gestimuleerde groei van het aantal WKO systemen. Gesloten WKO systemen zouden een risico kunnen vormen voor de kwaliteit van het grondwater door het groot aantal perforaties van de ondergrond en door het mogelijke lekken van koelvloeistof. Bij open WKO systemen moet voorkomen worden dat verschillende grondwaterlagen gemengd worden waardoor ongewenste geochemische en microbiologische processen optreden. In principe kan een open WKO systeem wel op een vervuilde locatie worden toegepast, maar er is specifiek maatwerk nodig om de verspreiding van de vervuiling te beperken. De bescheiden temperatuursveranderingen die door WKO systemen worden opgewekt in het grondwater vormen slechts een gering risico voor geochemische processen. Deze temperatuursveranderingen zouden in principe wel aanleiding kunnen geven tot een toename van het aantal ziektekiemen in het grondwater. Daarom is het belangrijk dat er voldoende afstand is tussen een drinkwaterwinning en de omringende WKO installaties. Verder onderzoek is nodig om vast te stellen welke invloed WKO installaties hebben op de bacteriën in het grondwater. Het opslaan van heet (90 °C) grondwater heeft een groot aantal milieubezwaren. De Europese kaderrichtlijn water ziet ook de inbreng van warmte in het grondwater als een mogelijke verontreiniging wanneer daar nadelige gevolgen voor mensen of ecosystemen aan verbonden zijn. Het toezicht van de provincies op het groeiende aantal WKO systemen in de praktijk verdient nadere aandacht
Influence of aging and dilution on the crystallization of silicate-1
The correlation between the formation of colloidal aggregates and the crystallization of silicalite-l from a clear solution has been investigated with in situ combined small-angle X-ray scattering and wide-angle X-ray scattering, and in situ ultra- small-angle X-ray scattering using synchrotron radiation. Increasing the aging time at room temperature of the synthesis mixture prior to heating to the reaction temperature reduced the induction period and increased the crystal growth rate without affecting the formation of colloidal aggregates. Dilution of the synthesis mixtures did not influence the nucleation and crystal growth rate, and did not affect the formation of colloidal aggregate
First-Time Parents Are Not Well Enough Prepared for the Safety of Their Infant
Background: Unintentional falls and poisonings are major causes of death and disability among infants. Although guidelines are available to prevent these injuries, safety behaviours are not performed by parents, causing unnecessary risks. Little is known about safety behaviours of first-time parents and whether they behave according to these guidelines. Aims/Objectives/Purpose: The objective of this study was to compare safety behaviours of first-time parents with those of non-first-time parents and to determine correlates of unsafe behaviour of parents of infants. We used self-report questionnaires to assess safety behaviours in a cross-sectional study sample. Methods: A total of 1439 parents visiting a preventive youth healthcare centre in the Netherlands were invited to complete a questionnaire with regard to the prevention of falls and poisonings. Parents were categorized into first-time parents and non-first-time parents. Correlates of parents' child safety behaviours were determined using multiple logistic regression analyses. Results/Outcome: Most respondents were mothers (93.2%); 48.2% of families were first-time parents. The mean age of the infants was 7.2 months (SD 1.1; range 4-12), 51.8% were boys, and 34.5% of infants could crawl. First-time parents were more likely not to have a stair gate installed (OR 16.46; 95% CI 12.36-21.93); were more likely to store cleaning products unsafely (OR 4.55; 95% CI 3.59-5.76); and were more likely to store medicines unsafely (OR 2.90; 95% CI 2.31-3.63) than non-first-time parents. First-time parents were more likely to not have a window guard installed (OR 1.52; 95% CI 1.08-2.15) (all P<0.05). Discussion/Conclusion: First-time parents are not well prepared for the safety of their infant, causing unnecessary risks. The various parents' safety behaviours were influenced by different variables, for example, age of the infant, crawling of the infant, mother's educational level, mother's ethnicity, self-efficacy, vulnerability, severity
Estimation of aerosol water and chemical composition from AERONET Sun–sky radiometer measurements at Cabauw, the Netherlands
Remote sensing of aerosols provides important information on atmospheric
aerosol abundance. However, due to the hygroscopic nature of aerosol
particles observed aerosol optical properties are influenced by atmospheric
humidity, and the measurements do not unambiguously characterize the aerosol
dry mass and composition, which complicates the comparison with aerosol
models. In this study we derive aerosol water and chemical composition by a
modeling approach that combines individual measurements of remotely sensed
aerosol properties (e.g., optical thickness, single-scattering albedo,
refractive index and size distribution) from an AERONET (Aerosol Robotic
Network) Sun–sky radiometer with radiosonde measurements of relative
humidity. The model simulates water uptake by aerosols based on the chemical
composition (e.g., sulfates, ammonium, nitrate, organic matter and black
carbon) and size distribution. A minimization method is used to calculate
aerosol composition and concentration, which are then compared to in situ
measurements from the Intensive Measurement Campaign At the Cabauw Tower
(IMPACT, May 2008, the Netherlands). Computed concentrations show good
agreement with campaign-average (i.e., 1–14 May) surface observations (mean
bias is 3% for PM<sub>10</sub> and 4–25% for the individual compounds). They
follow the day-to-day (synoptic) variability in the observations and are in
reasonable agreement for daily average concentrations (i.e., mean bias is
5% for PM<sub>10</sub> and black carbon, 10% for the inorganic salts and
18% for organic matter; root-mean-squared deviations are 26% for
PM<sub>10</sub> and 35–45% for the individual compounds). The modeled water
volume fraction is highly variable and strongly dependent on composition.
During this campaign we find that it is >0.5 at approximately 80% relative humidity
(RH) when the aerosol composition is dominated by hygroscopic inorganic salts, and
<0.1 when RH is below 40%, especially when the composition is
dominated by less hygroscopic compounds such as organic matter. The
scattering enhancement factor (f(RH), the ratio of the scattering coefficient
at 85% RH and its dry value at 676 nm) during 1–14 May is
2.6 ± 0.5. The uncertainty in AERONET (real) refractive index
(0.025–0.05) is the largest source of uncertainty in the modeled aerosol
composition and leads to an uncertainty of 0.1–0.25 (50–100%) in aerosol
water volume fraction. Our methodology performs relatively well at Cabauw,
but a better performance may be expected for regions with higher aerosol
loading where the uncertainties in the AERONET inversions are smaller
Ecological quality assessment of Dutch surface waters using a new bioassay with the cladoceran Chydorus sphaericus
Study of the Quantum Efficiency of CsI Photocathodes Exposed to Oxygen and Water Vapour
The operation of CsI photocathodes in gaseous detectors requires special attention to the purity of the applied gas mixtures.We have studied the influence of oxygen and water vapour contaminations on the performance of CsI photocathodes for theALICE HMPID RICH prototype. Measurements were done through comparison of Cherenkov rings obtained from beamtests. Increased levels of oxygen and water vapour did not show any effect on the performance. The results of this studyfound a direct application in the way of storing CsI photocathodes over long periods nad in particular in the shipment of theHMPID prototype from CERN to the STAR experiment at BNL. (Abstract only available,full text to follow
Effectiveness of web-based tailored advice on parents' child safety behaviors: Randomized controlled trial
Background: Injuries at home are a major cause of death, disability, and loss of quality of life among young children. Despite
current safety education, required safety behavior of parents is often lacking. To prevent various childhood disorders, the application
of Web-based tools has increased the effectiveness of health promotion efforts. Therefore, an intervention with Web-based,
tailored, safety advice combined with personal counseling (E-Health4Uth home safety) was developed and applied.
Objective: To evaluate the effect of E-Health4Uth home safety on parents’ safety behaviors with regard to the prevention of
falls, poisoning, drowning, and burns.
Methods: A randomized controlled trial was conducted (2009-2011) among parents visiting well-baby clinics in the Netherlands.
Parents were randomly assigned to the intervention group (E-Health4Uth home safety intervention) or to the control condition
consisting of usual care. Parents in the intervention condition completed a Web-based safety behavior assessment questionnaire;
the resulting tailored safety advice was discussed with their child health care professional at a well-baby visit (age approximately
11 months). Parents in the control condition received counseling using generic safety information leaflets at this well-baby visit.
Parents’ child safety behaviors were derived from self-report questionnaires at baseline (age 7 months) and at follow-up (age 17
months). Each specific safety behavior was classified as safe/unsafe and a total risk score was calculated. Logistic and linear
regression analyses were used to reveal differences in safety behavior between the intervention and the control condition at
follow-up.
Results: A total of 1292 parents (response rate 44.79%) were analyzed. At follow-up, parents in the intervention condition
(n=643) showed significantly less unsafe behavior compared to parents in the control condition (n=649): top of staircase (23.91%
vs 32.19%; OR 0.65, 95% CI 0.50-0.85); bottom of staircase (63.53% vs 71.94%; OR 0.69, 95% CI 0.53-0.88); top and bottom
of staircase (68.94% vs 78.28%; OR 0.62, 95% CI 0.48-0.81); storage of cleaning products (30.33% vs 39.91%; OR 0.67, 95%
CI 0.53-0.85); bathing of the child (23.46% vs 32.25%; OR 0.65, 95% CI 0.51-0.84); drinking hot fluids (34.84% vs 41.73%;
OR 0.76, 95% CI 0.61-0.96); using rear hotplates (79.34% vs 85.27%; OR 0.67, 95% CI 0.50-0.90); and the total risk score in
which a higher score indicates more unsafe behavior (mean 13.63, SD 6.12 vs mean 15.34, SD 6.07; beta –1.59, 95% CI –2.26
to –0.93). There were no significant differences for other specific behaviors between the two study conditions.
Conclusions: Compared to generic written materials, the E-Health
First detection of [CII]158um at high redshift: vigorous star formation in the early universe
We report the detection of the 2P_3/2 -> 2P_1/2 fine-structure line of C+ at
157.74 micron in SDSSJ114816.64+525150.3 (hereafter J1148+5251), the most
distant known quasar, at z=6.42, using the IRAM 30-meter telescope. This is the
first detection of the [CII] line at high redshift, and also the first
detection in a Hyperluminous Infrared Galaxy (L_FIR > 10^13 Lsun). The [CII]
line is detected at a significance level of 8 sigma and has a luminosity of 4.4
x 10^9 Lsun. The L_[CII]/L_FIR ratio is 2 x 10^-4, about an order of magnitude
smaller than observed in local normal galaxies and similar to the ratio
observed in local Ultraluminous Infrared Galaxies. The [CII] line luminosity
indicates that the host galaxy of this quasar is undergoing an intense burst of
star formation with an estimated rate of ~3000 Msun/yr. The detection of C+ in
SDSS J1148+5251 suggests a significant enrichment of metals at z ~ 6 (age of
the universe ~870 Myr), although the data are consistent with a reduced carbon
to oxygen ratio as expected from chemical evolutionary models of the early
phases of galaxy formation.Comment: 5 pages, 2 figures, accepted by A&A Letter
Gas and dust in a submillimeter galaxy at z = 4.24 from the Herschel ATLAS
We report ground-based follow-up observations of the exceptional source,
ID141, one the brightest sources detected so far in the H-ATLAS cosmological
survey. ID141 was observed using the IRAM 30-meter telescope and Plateau de
Bure interferometer (PdBI), the Submillimeter Array (SMA) and the Atacama
Pathfinder Experiment (APEX) submillimeter telescope to measure the dust
continuum and emission lines of the main isotope of carbon monoxide and carbon
([C I] and [C II]). The detection of strong CO emission lines with the PdBI
confirms that ID141 is at high redshift (z=4.243 +/- 0.001). The strength of
the continuum and emission lines suggests that ID141 is gravitationally lensed.
The width (Delta V (FWHM) ~ 800 km/s}) and asymmetric profiles of the CO and
carbon lines indicate orbital motion in a disc or a merger. The properties
derived for ID141 are compatible with a ultraluminous (L_FIR ~ 8.5 +/- 0.3 x
10^13/mu_L Lsun, where mu_L is the amplification factor, dense (n ~ 10^4 cm^-3)
and warm (T_kin ~ 40K) starburst galaxy, with an estimated star-formation rate
of (0.7 to 1.7) x 10^4/mu_L Msun/yr. The carbon emission lines indicate a dense
(n ~ 10^4 cm^-3) Photo-Dominated Region, illuminated by a far-UV radiation
field a few thousand times more intense than that in our Galaxy. In conclusion,
the physical properties of the high-z galaxy, ID141, are remarkably similar to
those of local ultraluminous infrared galaxies.Comment: To appear in Ap
Pattern of muscle strength improvement after intravenous immunoglobulin therapy in multifocal motor neuropathy
INTRODUCTION: In multifocal motor neuropathy (MMN), knowledge about the pattern of treatment response in a wide spectrum of muscle groups, distal as well as proximal, after intravenous immunoglobulin (IVIg) initiation is lacking. METHODS: Hand-held dynamometry data of 11 upper and lower limb muscles, from 47 patients with MMN was reviewed. Linear mixed models were used to determine the treatment response after IVIg initiation and its relationship with initial muscle weakness. RESULTS: All muscle groups showed a positive treatment response after IVIg initiation. Changes in SD scores ranged from +0.1 to +0.95. A strong association between weakness at baseline and the magnitude of the treatment response was found. DISCUSSION: Improved muscle strength in response to IVIg appears not only in distal, but to a similar degree also in proximal muscle groups in MMN, with the largest response in muscle groups that show the greatest initial weakness
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