Comparison between two mobile absolute gravimeters: optical versus atomic interferometers

We report a comparison between two absolute gravimeters: the LNE-SYRTE cold atoms gravimeter and FG5#220 of Leibniz Universit\"at of Hannover. They rely on different principles of operation: atomic and optical interferometry. Both are movable which enabled them to participated to the last International Comparison of Absolute Gravimeters (ICAG'09) at BIPM. Immediately after, their bilateral comparison took place in the LNE watt balance laboratory and showed an agreement of 4.3 +/- 6.4 {\mu}Gal

A surface-patterned chip as a strong source of ultracold atoms for quantum technologies

Laser-cooled atoms are central to modern precision measurements. They are also increasingly important as an enabling technology for experimental cavity quantum electrodynamics, quantum information processing and matter–wave interferometry. Although significant progress has been made in miniaturizing atomic metrological devices, these are limited in accuracy by their use of hot atomic ensembles and buffer gases. Advances have also been made in producing portable apparatus that benefits from the advantages of atoms in the microkelvin regime. However, simplifying atomic cooling and loading using microfabrication technology has proved difficult. In this Letter we address this problem, realizing an atom chip that enables the integration of laser cooling and trapping into a compact apparatus. Our source delivers ten thousand times more atoms than previous magneto-optical traps with microfabricated optics and, for the first time, can reach sub-Doppler temperatures. Moreover, the same chip design offers a simple way to form stable optical lattices. These features, combined with simplicity of fabrication and ease of operation, make these new traps a key advance in the development of cold-atom technology for high-accuracy, portable measurement devices

Dual-wavelength laser source for onboard atom interferometry

We present a compact and stable dual-wavelength laser source for onboard atom interferometry with two different atomic species. It is based on frequency-doubled telecom lasers locked on a femtosecond optical frequency comb. We take advantage of the maturity of fiber telecom technology to reduce the number of free-space optical components which are intrinsically less stable, and to make the setup immune to vibrations and thermal fluctuations. The source provides the frequency agility and phase stability required for atom interferometry and can easily be adapted to other cold atom experiments. We have shown its robustness by achieving the first dual-species K-Rb magneto optical trap in microgravity during parabolic flights

A radiofrequency heated reactor system for post-combustion carbon capture

Several problems with stabilization of electricity grid system are related to the time lag between the electricity supply and demand of the end users. Many power plants run for a limited period of time to compensate for increased electricity demand during peak hours. The amount of CO2 generated by these power installations can be substantially reduced via the development of new demand side management strategies utilizing CO2 absorption units with a short start-up time. The sorbent can be discharged using radiofrequency (RF) heating to fill the night-time valley in electricity demand helping in the stabilization of electricity grid. Herein a concept of RF heated fixed bed reactor has been demonstrated to remove CO2 from a flue gas using a CaCO3 sorbent. A very stable and reproducible operation has been observed over twenty absorption-desorption cycles. The application of RF heating significantly reduced the transition time required for temperature excursions between the absorption and desorption cycles. The effect of flow reversal during desorption on desorption time has been investigated. The desorption time was reduced by 1.5 times in the revered flow mode and the total duration of a single absorption-desorption cycle was reduced by 20%. A reactor model describing the reduced desorption time has been developed

Dynamics of global forest area: Results from the FAO Global Forest Resources Assessment 2015

The area of land covered by forest and trees is an important indicator of environmental condition. This study presents and analyses results from the Global Forest Resources Assessment 2015 (FRA 2015) of the Food and Agriculture Organization of the United Nations. FRA 2015 was based on responses to surveys by individual countries using a common reporting framework, agreed definitions and reporting standards. Results indicated that total forest area declined by 3%, from 4128 M ha in 1990 to 3999 M ha in 2015. The annual rate of net forest loss halved from 7.3 M ha y−1 in the 1990s to 3.3 M ha y−1 between 2010 and 2015. Natural forest area declined from 3961 M ha to 3721 M ha between 1990 and 2015, while planted forest (including rubber plantations) increased from 168 M ha to 278 M ha. From 2010 to 2015, tropical forest area declined at a rate of 5.5 M ha y−1 – only 58% of the rate in the 1990s – while temperate forest area expanded at a rate of 2.2 M ha y−1. Boreal and sub-tropical forest areas showed little net change. Forest area expanded in Europe, North America, the Caribbean, East Asia, and Western-Central Asia, but declined in Central America, South America, South and Southeast Asia and all three regions in Africa. Analysis indicates that, between 1990 and 2015, 13 tropical countries may have either passed through their forest transitions from net forest loss to net forest expansion, or continued along the path of forest expansion that follows these transitions. Comparing FRA 2015 statistics with the findings of global and pan-tropical remote-sensing forest area surveys was challenging, due to differences in assessment periods, the definitions of forest and remote sensing methods. More investment in national and global forest monitoring is needed to provide better support for international initiatives to increase sustainable forest management and reduce forest loss, particularly in tropical countries

Installation and Hardware commissioning of the Multi-Turn extraction at the CERN proton synchrotron

The implementation of the new Multi-Turn Extraction (MTE) at the CERN Proton Synchrotron required major hardware changes for the nearly 50-year old accelerator. The installation of new Pulse Forming Networks (PFN) and refurbished kicker magnets for the extraction, new sextupole and octupole magnets, new power converters, together with an in-depth review of the machine aperture leading to the design of new vacuum chambers was required. As a result, a heavy programme of interventions had to be scheduled during the winter shut-down 2007-8. The newly installed hardware and its commissioning is presented and discussed in details

Molecular Implication of PP2A and Pin1 in the Alzheimer's Disease Specific Hyperphosphorylation of Tau

Tau phosphorylation and dephosphorylation regulate in a poorly understood manner its physiological role of microtubule stabilization, and equally its integration in Alzheimer disease (AD) related fibrils. A specific phospho-pattern will result from the balance between kinases and phosphatases. The heterotrimeric Protein Phosphatase type 2A encompassing regulatory subunit PR55/Bα (PP2A(T55α)) is a major Tau phosphatase in vivo, which contributes to its final phosphorylation state. We use NMR spectroscopy to determine the dephosphorylation rates of phospho-Tau by this major brain phosphatase, and present site-specific and kinetic data for the individual sites including the pS202/pT205 AT8 and pT231 AT180 phospho-epitopes.We demonstrate the importance of the PR55/Bα regulatory subunit of PP2A within this enzymatic process, and show that, unexpectedly, phosphorylation at the pT231 AT180 site negatively interferes with the dephosphorylation of the pS202/pT205 AT8 site. This inhibitory effect can be released by the phosphorylation dependent prolyl cis/trans isomerase Pin1. Because the stimulatory effect is lost with the dimeric PP2A core enzyme (PP2A(D)) or with a phospho-Tau T231A mutant, we propose that Pin1 regulates the interaction between the PR55/Bα subunit and the AT180 phospho-epitope on Tau.Our results show that phosphorylation of T231 (AT180) can negatively influence the dephosphorylation of the pS202/pT205 AT8 epitope, even without an altered PP2A pool. Thus, a priming dephosphorylation of pT231 AT180 is required for efficient PP2A(T55α)-mediated dephosphorylation of pS202/pT205 AT8. The sophisticated interplay between priming mechanisms reported for certain Tau kinases and the one described here for Tau phosphatase PP2A(T55α) may contribute to the hyperphosphorylation of Tau observed in AD neurons

Growth Hormone Secretagogues Protect Mouse Cardiomyocytes from in vitro Ischemia/Reperfusion Injury through Regulation of Intracellular Calcium

Background: Ischemic heart disease is a leading cause of mortality. To study this disease, ischemia/reperfusion (I/R) models are widely used to mimic the process of transient blockage and subsequent recovery of cardiac coronary blood supply. We aimed to determine whether the presence of the growth hormone secretagogues, ghrelin and hexarelin, would protect/improve the function of heart from I/R injury and to examine the underlying mechanisms. Methodology/Principal Findings: Isolated hearts from adult male mice underwent 20 min global ischemia and 30 min reperfusion using a Langendorff apparatus. Ghrelin (10 nM) or hexarelin (1 nM) was introduced into the perfusion system either 10 min before or after ischemia, termed pre- and post-treatments. In freshly isolated cardiomyocytes from these hearts, single cell shortening, intracellular calcium ([Ca ] ) transients and caffeine-releasable sarcoplasmic reticulum (SR) Ca were measured. In addition, RT-PCR and Western blots were used to examine the expression level of GHS receptor type 1a (GHS-R1a), and phosphorylated phospholamban (p-PLB), respectively. Ghrelin and hexarelin pre- or post-treatments prevented the significant reduction in the cell shortening, [Ca ] transient amplitude and caffeine-releasable SR Ca content after I/R through recovery of p-PLB. GHS-R1a antagonists, [D-Lys3]-GHRP-6 (200 nM) and BIM28163 (100 nM), completely blocked the effects of GHS on both cell shortening and [Ca ] transients. Conclusion/Significance: Through activation of GHS-R1a, ghrelin and hexarelin produced a positive inotropic effect on ischemic cardiomyocytes and protected them from I/R injury probably by protecting or recovering p-PLB (and therefore SR Ca content) to allow the maintenance or recovery of normal cardiac contractility. These observations provide supporting evidence for the potential therapeutic application of ghrelin and hexarelin in patients with cardiac I/R injury