Personal Food Computer: A new device for controlled-environment agriculture

Due to their interdisciplinary nature, devices for controlled-environment agriculture have the possibility to turn into ideal tools not only to conduct research on plant phenology but also to create curricula in a wide range of disciplines. Controlled-environment devices are increasing their functionalities as well as improving their accessibility. Traditionally, building one of these devices from scratch implies knowledge in fields such as mechanical engineering, digital electronics, programming, and energy management. However, the requirements of an effective controlled environment device for personal use brings new constraints and challenges. This paper presents the OpenAg Personal Food Computer (PFC); a low cost desktop size platform, which not only targets plant phenology researchers but also hobbyists, makers, and teachers from elementary to high-school levels (K-12). The PFC is completely open-source and it is intended to become a tool that can be used for collective data sharing and plant growth analysis. Thanks to its modular design, the PFC can be used in a large spectrum of activities.Comment: 9 pages, 11 figures, Accepted at the 2017 Future Technologies Conference (FTC

Individual Oligodendrocytes Have Only a Few Hours in which to Generate New Myelin Sheaths In Vivo

The number of myelin sheaths made by individual oligodendrocytes regulates the extent of myelination, which profoundly affects central nervous system function. It remains unknown when, during their life, individual oligodendrocytes can regulate myelin sheath number in vivo. We show, using live imaging in zebrafish, that oligodendrocytes make new myelin sheaths during a period of just 5 hr, with regulation of sheath number after this time limited to occasional retractions. We also show that activation and reduction of Fyn kinase in oligodendrocytes increases and decreases sheath number per cell, respectively. Interestingly, these oligodendrocytes also generate their new myelin sheaths within the same period, despite having vastly different extents of myelination. Our data demonstrate a restricted time window relative to the lifetime of the individual oligodendrocyte, during which myelin sheath formation occurs and the number of sheaths is determined

Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS-100)

MAGIS-100 is a next-generation quantum sensor under construction at Fermilab that aims to explore fundamental physics with atom interferometry over a 100-meter baseline. This novel detector will search for ultralight dark matter, test quantum mechanics in new regimes, and serve as a technology pathfinder for future gravitational wave detectors in a previously unexplored frequency band. It combines techniques demonstrated in state-of-the-art 10-meter-scale atom interferometers with the latest technological advances of the world's best atomic clocks. MAGIS-100 will provide a development platform for a future kilometer-scale detector that would be sufficiently sensitive to detect gravitational waves from known sources. Here we present the science case for the MAGIS concept, review the operating principles of the detector, describe the instrument design, and study the detector systematics.Comment: 65 pages, 18 figure

Electron Diffraction from Free-Standing, Metal-Coated Transmission Gratings

Electron diffraction from a free-standing nanofabricated transmission grating was demonstrated, with energies ranging from 125 eV to 25 keV. Observation of 21 diffraction orders highlights the quality of the gratings. The image charge potential due to one electron was measured by rotating the grating. These gratings may pave the way to low-energy electron interferometry

Supramolecular Nanostamping: Using DNA as Movable Type

Here we present a novel printing technique (that we call supramolecular nanostamping), based on the replication of single-stranded DNA features through a hybridization-contact-dehybridization cycle. On a surface containing features each made of single-stranded DNA molecules of known sequence, the complementary DNA molecules are hybridized, spontaneously assembling onto the original pattern due to sequence-specific interactions. These complementary DNA strands, on the end that is assembled far from the original surface, are 5' modified with chemical groups ("sticky ends") that can form bonds with a target surface that is brought into contact. Heating induces dehybridization between DNA strands, leaving the original pattern on the original surface and the copied pattern on the secondary substrate, and thus stamping (see Figure 1). Molecular recognition provides the unique and disruptive ability of transferring large amounts of information in a single printing cycle, that is the simultaneous stamping of spatial information (i.e., the patterns) and of chemical information (i.e., the features' DNA sequence - their chemical composition). This method combines high resolution (< 40 nm) with the advantage of an exponential increase in the number of masters; in fact, any printed substrate can be reused as a master. Patterns fabricated via very different lithographic techniques can be replicated

A Kapitza–Dirac–Talbot–Lau interferometer for highly polarizable molecules

Research on matter waves is a thriving field of quantum physics and has recently stimulated many investigations with electrons, neutrons, atoms, Bose-condensed ensembles, cold clusters and hot molecules. Coherence experiments with complex objects are of interest for exploring the transition to classical physics, for measuring molecular properties and they have even been proposed for testing new models of space-time. For matter-wave experiments with complex molecules, the strongly dispersive effect of the interaction between the diffracted molecule and the grating wall is a major challenge because it imposes enormous constraints on the velocity selection of the molecular beam. We here describe the first experimental realization of a new interferometer that solves this problem by combining the advantages of a Talbot-Lau setup with the benefits of an optical phase grating and we show quantum interference with new large molecules.Comment: 13 pages, 4 figure