568 research outputs found
CO2 sensing with chemoresistive Nd2O2CO3 sensors - Operando insights
AbstractIn this work the sensing of Nd2O2CO3-based chemoresistive CO2 sensor was investigated combining DRIFT and DC-resistance measurements. Besides the already reported effect of CO2 exposure, we found that exposure to CO determines comparable effects and that the presence of oxygen in the background is not important. The humidity significantly influences the response for both gases. The spectroscopic results reveal that the exposure to both CO and CO2 consumes the water-related surface species â the rooted-hydroxyls being the electrically active one â and increases the concentration of carbonates; the decrease of the rooted-hydroxyls is probably the cause of the resistance increase
Rare earth oxycarbonates as a material class for chemoresistive CO2 gas sensors
AbstractIn this work we compare the CO2 gas sensing properties of two new materials synthesized from rare earth hydroxide (La(OH)3,Pr(OH)3) precursors, with the already reported ones for neodymium oxycarbonate, which was synthesized from the corresponding Nd(OH)3 precursor. In-situ XRD measurements show that by following similar thermal treatment, praseodymium hydroxide is transforming to the metal oxide while lanthanum hydroxide forms an oxycarbonate, like in the case of neodymium. The chemoresistive effects we found for the lanthanum oxycarbonate were even higher than the ones recorded for the neodymium oxycarbonate; for the praseodymium metal oxide we could not find any CO2 sensitivity. Accordingly, we think that the condition for CO2 sensing is the formation of the rare earth oxycarbonate
Disorder-Induced Order in Quantum XY Chains
We observe signatures of disorder-induced order in 1D XY spin chains with an
external, site-dependent uni-axial random field within the XY plane. We
numerically investigate signatures of a quantum phase transition at T=0, in
particular an upsurge of the magnetization in the direction orthogonal to the
external magnetic field, and the scaling of the block-entropy with the
amplitude of this field. Also, we discuss possible realizations of this effect
in ultra-cold atom experiments
Microsatellite instability and defects in mismatch repair proteins: a new aetiology for Sertoli cellâonly syndrome
Microsatellite instability is characteristic of certain types of cancer, and is present in rodents lacking specific DNA mismatch repair proteins. These azoospermic mice exhibit spermatogenic defects similar to some human testicular failure patients. Therefore, we hypothesized that microsatellite instability due to deficiencies in mismatch repair genes might be an unrecognized aetiology of human testicular failure. Because these azoospermic patients are candidates for testicular sperm extraction and ICSI, transmission of mismatch repair defects to the offspring is possible. Seven microsatellite loci were analysed for instability in specimens from 41 testicular failure patients and 20 controls. Blood and testicular DNA were extracted from patient and control specimens, and amplified by PCR targeting seven microsatellite loci. DNA fragment length was analysed with an ABI Prism 310 Genotyping Machine and GeneScan software. Immunohistochemistry was performed on paraffinized testis biopsy sections and cultured testicular fibroblasts from each patient to determine if expression of the mismatch repair proteins hMSH2 and hMLH1 was normal in both somatic and germline cells. Results demonstrate that microsatellite instability and DNA mismatch repair protein defects are present in some azoospermic men, predominantly in Sertoli cellâonly patients (P < 0.01 and P < 0.05 respectively). This provides evidence of a previously unrecognized aetiology of testicular failure that may be associated with cancer predispositio
Transport regimes of cold gases in a two-dimensional anisotropic disorder
We numerically study the dynamics of cold atoms in a two-dimensional
disordered potential. We consider an anisotropic speckle potential and focus on
the classical regime, which is relevant to some recent experiments. First, we
study the behavior of particles with a fixed energy and identify different
transport regimes. For low energy, the particles are classically localized due
to the absence of a percolating cluster. For high energy, the particles undergo
normal diffusion and we show that the diffusion constants scale algebraically
with the particle energy, with an anisotropy factor which significantly differs
from that of the disordered potential. For intermediate energy, we find a
transient sub-diffusive regime, which is relevant to the time scale of typical
experiments. Second, we study the behavior of a cold-atomic gas with an
arbitrary energy distribution, using the above results as a groundwork. We show
that the density profile of the atomic cloud in the diffusion regime is
strongly peaked and, in particular, that it is not Gaussian. Its behavior at
large distances allows us to extract the energy-dependent diffusion constants
from experimental density distributions. For a thermal cloud released into the
disordered potential, we show that our numerical predictions are in agreement
with experimental findings. Not only does this work give insights to recent
experimental results, but it may also serve interpretation of future
experiments searching for deviation from classical diffusion and traces of
Anderson localization.Comment: 19 pages, 16 figure
Disorder-Induced Phase Control in Superfluid Fermi-Bose Mixtures
We consider a mixture of a superfluid Fermi gas of ultracold atoms and a
Bose-Einstein condensate of molecules possessing a continuous U(1) (relative
phase) symmetry. We study the effects that a spatially random
photo-associative-dissociative symmetry breaking coupling of the systems. Such
coupling allows to control the relative phase between a superfluid order
parameter of the Fermi system and the condensate wavefunction of molecules for
temperatures below the BCS critical temperature. The presented mechanism of
phase control belongs to the general class of disorder-induced order phenomena
that rely on breaking of continuous symmetry.Comment: 4 pages, 2 figure
Transcendental-Phenomenological Proof and Descriptive Metaphysics
Following P.F. Strawson's reading of Kant, the majority of the literature on transcendental arguments seeks to divorce such arguments from their original Kantian context. This thesis is concerned with Mark Sacks's recent defence of transcendental arguments, which takes a different approach. A critique is given of Sacks's work and extensions and modifications of his approach are recommended. It is proposed that certain difficulties encountered by Kant's transcendentally-ideal approach can be overcome with Hegelian solutions
Novel sulfur-oxidizing streamers thriving in a perennial cold saline springs of the Canadian high Arctic
The perennial springs at Gypsum Hill (GH) and Colour Peak (CP), situated at nearly 80\ub0N on Axel Heiberg Island in the Canadian high Arctic, are one of the few known examples of cold springs in thick permafrost on Earth. The springs emanate from deep saline aquifers and discharge cold anoxic brines rich in both sulfide and sulfate. Grey-coloured microbial streamers form during the winter months in snow-covered regions of the GH spring run-off channels (-1.3\ub0C to 6.9\ub0C, ~7.5% NaCl, 0\u201320 p.p.m. dissolved sulfide, 1 p.p.m. dissolved oxygen) but disappear during the Arctic summer. Culture- and molecular-based analyses of the 16S rRNA gene (FISH, DGGE and clone libraries) indicated that the streamers were uniquely dominated by chemolithoautotrophic sulfur-oxidizing Thiomicrospira species. The streamers oxidized both sulfide and thiosulfate and fixed CO2 under in situ conditions and a Thiomicrospira strain isolated from the streamers also actively oxidized sulfide and thiosulfate and fixed CO2 under cold, saline conditions. Overall, the snow-covered spring channels appear to represent a unique polar saline microhabitat that protects and allows Thiomicrospira streamers to form and flourish via chemolithoautrophic, phototrophicindependent metabolism in a high Arctic winter environment characterized by air temperatures commonly below -40\ub0C and with an annual average air temperature of -15\ub0C. These results broaden our knowledge of the physical and chemical boundaries that define life on Earth and have astrobiological implications for the possibility of life existing under similar Martian conditions.NRC publication: Ye
Standardizing definitions and reporting guidelines for the infertility core outcome set : an international consensus development study
Acknowledgments We would like to thank the consensus development meeting participants and colleagues at the Cochrane Gynaecology and Fertility Group, University of Auckland, New Zealand. Funding This research was funded by the Catalyst Fund, Royal Society of New Zealand, Auckland Medical Research Fund and Maurice and Phyllis Paykel Trust. The funder had no role in the design and conduct of the study, the collection, management, analysis or interpretation of data or manuscript preparation. Siladitya Bhattacharya was supported by the University of Auckland Foundation Seelye Travelling Fellowship. B.W.M. is supported by a National Health and Medical Research Council Practitioner Fellowship (GNT1082548) This article has not been externally peer reviewed. This article has been published simultaneously in Fertility and SterilityPeer reviewedPublisher PD
Assessment of Acceptable Swiss post-2012 Climate Policies
In the framework of the revision of the Swiss CO2-Law and in the preparation of the international negotiations that place at the Conference of the Parties to the United Nations Framework Convention on Climate Change, the Swiss Government has proposed a set of instruments and two levels of abatement to define the Swiss climate policy for the post-2012 period. By 2030, Switzerland would recuce its GHG emission by 30% or 45%, depending on whether or not the rest of the world world would commit to strong emissions reductions. The proposed policies are the result of consultation procedures take into account the views of major stakeholders and lobbies and allow for differienciated carbon prices in different sectors of the Swiss economy. Linking a Cumputable General Equilibrium (CGE) and two sectoral energy models, we evaluate the policies for the two scenarios. We find important disparities in the prices of carbon faced by the different economic sectors and higher welfare costs than those that would be triggered by a uniform carbon tax
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