Het veranderen van opvattingen van chemiedocenten door partici-patie in een ontwikkelnetwerk

Opvattingen over leren en onderwijzen spelen bij het handelen van docenten een grote rol. Omdat opvattingen diep geworteld zijn in de ervaringen van docenten blijken ze moeilijk te veranderen. Wil een curriculumverandering succesvol zijn dan moeten de opvattingen van docenten erbij worden betrokken.\ud Het invoeren van een vernieuwing kan gezien worden als een leerproces van docenten, waarin aandacht is voor vakinhoud en didactiek maar ook voor opvattingen. Een van de manieren om dit leerproces vorm en inhoud te geven is door het opzetten van netwerken van docenten. De netwerken ontwikkelen leermaterialen voor leerlingen en de deelnemers gebruiken deze materialen in hun onderwijs. Het netwerk kan worden gezien als een leergemeenschap.\ud De vraag in dit onderzoek is hoe de opvattingen van docenten door participatie in een ontwikkelnetwerk veranderen. De opvattingen van de docenten zijn daarvoor op drie momenten tijdens het ontwikkelproces vastgelegd, waarbij gebruik gemaakt is van meerdere instrumenten

Fast adiabatic transport of single laser-cooled 9^9Be+^+ ions in a cryogenic Penning trap stack

High precision mass and $g$-factor measurements in Penning traps have enabled groundbreaking tests of fundamental physics. The most advanced setups use multi-trap methods, which employ transport of particles between specialized trap zones. Present developments focused on the implementation of sympathetic laser cooling will enable significantly shorter duty cycles and better accuracies in many of these scenarios. To take full advantage of these increased capabilities, we implement fast adiabatic transport concepts developed in the context of trapped-ion quantum information processing in a cryogenic Penning trap system. We show adiabatic transport of a single $^9\mathrm{Be}^+$ ion initially cooled to 2 mK over a 2.2 cm distance within 15 ms and with less than 10\,mK energy gain at a peak velocity of 3 m/s. These results represent an important step towards the implementation of quantum logic spectroscopy in the \ppbar system. Applying these developments to other multi-trap systems has the potential to considerably increase the data-sampling rate in these experiments.Comment: 15 pages, 7 figure

Rainfall interception and redistribution by a common North American understory and pasture forb, \u3cem\u3eEupatorium capillifolium\u3c/em\u3e (Lam. dogfennel)

In vegetated landscapes, rain must pass through plant canopies and litter to enter soils. As a result, some rainwater is returned to the atmosphere (i.e., interception, I) and the remainder is partitioned into a canopy (and gap) drip flux (i.e., throughfall) or drained down the stem (i.e., stemflow). Current theoretical and numerical modeling frameworks for this process are almost exclusively based on data from woody overstory plants. However, herbaceous plants often populate the understory and are the primary cover for important ecosystems (e.g., grasslands and croplands). This study investigates how overstory throughfall (PT,o) is partitioned into understory I, throughfall (PT) and stemflow (PS) by a dominant forb in disturbed urban forests (as well as grasslands and pasturelands), Eupatorium capillifolium (Lam., dogfennel). Dogfennel density at the site was 56 770 stems ha−1, enabling water storage capacities for leaves and stems of 0.90±0.04 and 0.43±0.02 mm, respectively. As direct measurement of PT,o (using methods such as tipping buckets or bottles) would remove PT,o or disturb the understory partitioning of PT,o, overstory throughfall was modeled (PT,o′ role= presentation \u3eP′T,o) using on-site observations of PT,o from a previous field campaign. Relying on modeled PT,o′ role= presentation \u3eP′T,o, rather than on observations of PT,o directly above individual plants means that significant uncertainty remains with respect to (i) small-scale relative values of PT and PS and (ii) factors driving PS variability among individual dogfennel plants. Indeed, PS data from individual plants were highly skewed, where the mean PS:PT,o′ role= presentation \u3ePS:P′T,o per plant was 36.8 %, but the median was 7.6 % (2.8 %–27.2 % interquartile range) and the total over the study period was 7.9 %. PS variability (n=30 plants) was high (CV \u3e 200 %) and may hypothetically be explained by fine-scale spatiotemporal patterns in actual overstory throughfall (as no plant structural factors explained the variability). The total PT:PT,o′ role= presentation \u3ePT:P′T,o was 71 % (median PT:PT,o′ role= presentation \u3ePT:P′T,o per gauge was 72 %, with a 59 %–91 % interquartile range). Occult precipitation (mixed dew and light rain events) occurred during the study period, revealing that dogfennel can capture and drain dew to their stem base as PS. Dew-induced PS may help explain dogfennel\u27s improved invasion efficacy during droughts (as it tends to be one of the most problematic weeds in the improved grazing systems in the southeastern US). Overall, dogfennel\u27s precipitation partitioning differed markedly from the site\u27s overstory trees (Pinus palustris), and a discussion of the limited literature suggests that these differences may exist across vegetated ecosystems. Thus, more research on herbaceous plant canopy interactions with precipitation is merited

Contextual factors and prejudice at the beginning of the migrant influx: The Moroccan case in Seville, Spain

Studies addressing contextual factors associated with anti‐immigrant prejudice have focused on out‐group size and rapid demographic changes in receiving locations. However, the territorial concentration and distribution of ethnic minorities at a local and intraurban level has received little attention. We analyse the relationship between emerging territorial concentration points—alongside other contextual variables—by Moroccans and receiving society's growing prejudice towards them in a city experiencing the start of a migrant influx. We combine survey and census data from five Seville districts (southern Spain). Our results show how rapid changes in the general population's ethnic composition, coupled with Moroccan and economic migrants' territorial concentration, correlate strongly with negative attitudes towards Moroccans at this early stage. However, a weaker relationship between the immigrant percentage and degree of prejudice by the receiving group is observed. We also discuss guidelines for ensuring good, local diversity management to prevent socioterritorial fragmentation in multicultural cities.Ministerio de Economía, Industria y Competitividad de España CSO2014‐55780‐C3‐1‐PMinisterio de Economía, Industria y Competitividad de España SEJ2006-14470Junta de Andalucí

Search for non-relativistic Magnetic Monopoles with IceCube

The IceCube Neutrino Observatory is a large Cherenkov detector instrumenting $1\,\mathrm{km}^3$ of Antarctic ice. The detector can be used to search for signatures of particle physics beyond the Standard Model. Here, we describe the search for non-relativistic, magnetic monopoles as remnants of the GUT (Grand Unified Theory) era shortly after the Big Bang. These monopoles may catalyze the decay of nucleons via the Rubakov-Callan effect with a cross section suggested to be in the range of $10^{-27}\,\mathrm{cm^2}$ to $10^{-21}\,\mathrm{cm^2}$. In IceCube, the Cherenkov light from nucleon decays along the monopole trajectory would produce a characteristic hit pattern. This paper presents the results of an analysis of first data taken from May 2011 until May 2012 with a dedicated slow-particle trigger for DeepCore, a subdetector of IceCube. A second analysis provides better sensitivity for the brightest non-relativistic monopoles using data taken from May 2009 until May 2010. In both analyses no monopole signal was observed. For catalysis cross sections of $10^{-22}\,(10^{-24})\,\mathrm{cm^2}$ the flux of non-relativistic GUT monopoles is constrained up to a level of $\Phi_{90} \le 10^{-18}\,(10^{-17})\,\mathrm{cm^{-2}s^{-1}sr^{-1}}$ at a 90% confidence level, which is three orders of magnitude below the Parker bound. The limits assume a dominant decay of the proton into a positron and a neutral pion. These results improve the current best experimental limits by one to two orders of magnitude, for a wide range of assumed speeds and catalysis cross sections.Comment: 20 pages, 20 figure

All-sky search for time-integrated neutrino emission from astrophysical sources with 7 years of IceCube data

Since the recent detection of an astrophysical flux of high energy neutrinos, the question of its origin has not yet fully been answered. Much of what is known about this flux comes from a small event sample of high neutrino purity, good energy resolution, but large angular uncertainties. In searches for point-like sources, on the other hand, the best performance is given by using large statistics and good angular reconstructions. Track-like muon events produced in neutrino interactions satisfy these requirements. We present here the results of searches for point-like sources with neutrinos using data acquired by the IceCube detector over seven years from 2008--2015. The discovery potential of the analysis in the northern sky is now significantly below $E_\nu^2d\phi/dE_\nu=10^{-12}\:\mathrm{TeV\,cm^{-2}\,s^{-1}}$, on average $38\%$ lower than the sensitivity of the previously published analysis of four years exposure. No significant clustering of neutrinos above background expectation was observed, and implications for prominent neutrino source candidates are discussed.Comment: 19 pages, 17 figures, 3 tables; ; submitted to The Astrophysical Journa

The IceCube Neutrino Observatory: Instrumentation and Online Systems

The IceCube Neutrino Observatory is a cubic-kilometer-scale high-energy neutrino detector built into the ice at the South Pole. Construction of IceCube, the largest neutrino detector built to date, was completed in 2011 and enabled the discovery of high-energy astrophysical neutrinos. We describe here the design, production, and calibration of the IceCube digital optical module (DOM), the cable systems, computing hardware, and our methodology for drilling and deployment. We also describe the online triggering and data filtering systems that select candidate neutrino and cosmic ray events for analysis. Due to a rigorous pre-deployment protocol, 98.4% of the DOMs in the deep ice are operating and collecting data. IceCube routinely achieves a detector uptime of 99% by emphasizing software stability and monitoring. Detector operations have been stable since construction was completed, and the detector is expected to operate at least until the end of the next decade.Comment: 83 pages, 50 figures; updated with minor changes from journal review and proofin