Authentieke contexten in wiskundemethoden in het vmbo

Centrale vraag Zijn de bestaande wiskundemethoden die gebruikt worden in de beroepsgerichte leerwegen van het vmbo bruikbaar in verband met authentiek leren en wat is daarvoor eventueel nog extra nodig. Belangrijkste conclusies De bestaande wiskundemethoden bevatten enkele authentieke leertaken, maar over het algemeen bevatten de opdrachten weinig kenmerken passend bij authentiek leren. Wel bevatten de boeken diverse aangrijpingspunten om, dicht bij de methode, meer authentieke leertaken te ontwikkelen. In deze publicatie worden aanbevelingen gedaan en enkele mogelijkheden daartoe beschreven. Dit is een Ico-Isor rapport

Effect multifasenvoedering op fosforuitscheiding en technische resultaten van vleesvarkens

Multifasenvoedering leidt ten opzichte van tweefasenvoedering niet tot slechtere technische resultaten bij vleesvarkens. Door toepassing van multifasenvoedering kan de fosforuitscheiding in het traject van opleg tot afleveren met 17% verminderd wordenten opzichte van tweefasenvoedering

Improving the scalability of cloud-based resilient database servers

Many rely now on public cloud infrastructure-as-a-service for database servers, mainly, by pushing the limits of existing pooling and replication software to operate large shared-nothing virtual server clusters. Yet, it is unclear whether this is still the best architectural choice, namely, when cloud infrastructure provides seamless virtual shared storage and bills clients on actual disk usage. This paper addresses this challenge with Resilient Asynchronous Commit (RAsC), an improvement to awell-known shared-nothing design based on the assumption that a much larger number of servers is required for scale than for resilience. Then we compare this proposal to other database server architectures using an analytical model focused on peak throughput and conclude that it provides the best performance/cost trade-off while at the same time addressing a wide range of fault scenarios

Bis(triphenyl­guanidinium) tetra­chlorido­cuprate(II)

The structure of the title compound, (C19H18N3)2[CuCl4], consists of square-planar [CuCl4]2− anions and triphenyl­guanidinium cations. The CuII ion occupies a crystallographic inversion centre. In the cation, the dihedral angles between the phenyl rings and the plane defined by the central guanidinium fragment are in the range 51.9 (4)–64.4 (3)°. N—H⋯Cl hydrogen bonds assemble the ions into infinite chains running along the b axis

N,N′,N′′-Triphenyl­guanidinium 5-nitro-2,4-dioxo-1,2,3,4-tetra­hydro­pyrimidin-1-ide

In the title compound, C19H18N3 +.C4H2N3O4 −, the dihedral angles between the phenyl rings and the plane defined by the central guanidinium fragment are in the range 41.3 (1)–66.6 (1)°. The pyrimidine ring of the anion is distorted towards a boat conformation and the nitro group is rotated 11.4 (2)° out of the uracil plane. Hydrogen bonds assemble the ions in infinite helical chains along the b axis

A Compact Cold-Atom Interferometer with a High Data-Rate Grating Magneto-Optical Trap and a Photonic-Integrated-Circuit-Compatible Laser System

The extreme miniaturization of a cold-atom interferometer accelerometer requires the development of novel technologies and architectures for the interferometer subsystems. Here we describe several component technologies and a laser system architecture to enable a path to such miniaturization. We developed a custom, compact titanium vacuum package containing a microfabricated grating chip for a tetrahedral grating magneto-optical trap (GMOT) using a single cooling beam. In addition, we designed a multi-channel photonic-integrated-circuit-compatible laser system implemented with a single seed laser and single sideband modulators in a time-multiplexed manner, reducing the number of optical channels connected to the sensor head. In a compact sensor head containing the vacuum package, sub-Doppler cooling in the GMOT produces 15 uK temperatures, and the GMOT can operate at a 20 Hz data rate. We validated the atomic coherence with Ramsey interferometry using microwave spectroscopy, then demonstrated a light-pulse atom interferometer in a gravimeter configuration for a 10 Hz measurement data rate and T = 0 - 4.5 ms interrogation time, resulting in $\Delta$ g / g = 2.0e-6. This work represents a significant step towards deployable cold-atom inertial sensors under large amplitude motional dynamics.Comment: 21 pages, 10 figure

Integration of fluorescence collection optics with a microfabricated surface electrode ion trap

We have successfully demonstrated an integrated optical system for collecting the fluorescence from a trapped ion. The system, consisting of an array of transmissive, dielectric micro-optics and an optical fiber array, has been intimately incorporated into the ion-trapping chip without negatively impacting trapping performance. Epoxies, vacuum feedthrough, and optical component materials were carefully chosen so that they did not degrade the vacuum environment, and we have demonstrated light detection as well as ion trapping and shuttling behavior comparable to trapping chips without integrated optics, with no modification to the control voltages of the trapping chip.Comment: 14 pages, 12 figure