Inverse modeling of the global methyl chloride sources

Inverse modeling using the Bayesian least squares method is applied to better constrain the sources and sinks of atmospheric methyl chloride (CH3Cl) using observations from seven surface stations and eight aircraft field experiments. We use a three-dimensional global chemical transport model, the GEOS-Chem, as the forward model. Up to 39 parameters describing the continental/hemispheric and seasonal dependence of the major sources of CH3Cl are used in the inversion. We find that the available surface and aircraft observations cannot constrain all the parameters, resulting in relatively large uncertainties in the inversion results. By examining the degrees of freedom in the inversion Jacobian matrix, we choose a reduced set of parameters that can be constrained by the observations while providing valuable information on the sources and sinks. In particular, we resolve the seasonal dependence of the biogenic and biomass-burning sources for each hemisphere. The in situ aircraft measurements are found to provide better constraints on the emission sources than surface measurements. The a posteriori emissions result in better agreement with the observations, particularly at southern high latitudes. The a posteriori biogenic and biomass-burning sources decrease by 13 and 11% to 2500 and 545 Gg yr-1, respectively, while the a posteriori net ocean source increases by about a factor of 2 to 761 Gg yr-1. The decrease in biomass-burning emissions is largely due to the reduction in the emissions in seasons other than spring in the Northern Hemisphere. The inversion results indicate that the biogenic source has a clear winter minimum in both hemispheres, likely reflecting the decrease of biogenic activity during that season. Copyright 2006 by the American Geophysical Union

Permission form synopses to improve parents' understanding of research: a randomized trial.

ObjectiveWe hypothesized that, among parents of potential neonatal research subjects, an accompanying cover sheet added to the permission form (intervention) would increase understanding of the research, when compared to a standard form (control).Study designThis pilot study enrolled parents approached for one of two index studies: one randomized trial and one observational study. A one-page cover sheet described critical study information. Families were randomized 1:1 to receive the cover sheet or not. Objective and subjective understanding and satisfaction were measured.ResultsThirty-two parents completed all measures (17 control, 15 intervention). There were no differences in comprehension score (16.8±5.7 vs 16.3±3.5), subjective understanding (median 6 vs 6.5), or overall satisfaction with consent (median 7 vs 6.5) between control and intervention groups (all P>0.50).ConclusionA simplified permission form cover sheet had no effect on parents' understanding of studies for which their newborns were being recruited

No Detectable Fertility Benefit from a Single Additional Mating in Wild Stalk-Eyed Flies

Background: Multiple mating by female insects is widespread, and the explanation(s) for repeated mating by females has been the subject of much discussion. Females may profit from mating multiply through direct material benefits that increase their own reproductive output, or indirect genetic benefits that increase offspring fitness. One particular direct benefit that has attracted significant attention is that of fertility assurance, as females often need to mate multiply to achieve high fertility. This hypothesis has never been tested in a wild insect population.Methodology/Principal Findings: Female Malaysian stalk-eyed flies (Teleopsis dalmanni) mate repeatedly during their lifetime, and have been shown to be sperm limited under both laboratory and field conditions. Here we ask whether receiving an additional mating alleviates sperm limitation in wild females. In our experiment one group of females received a single additional mating, while a control group received an interrupted, and therefore unsuccessful, mating. Females that received an additional mating did not lay more fertilised eggs in total, nor did they lay proportionately more fertilised eggs. Female fertility declined significantly through time, demonstrating that females were sperm limited. However, receipt of an additional mating did not significantly alter the rate of this decline.Conclusions/Significance: Our data suggest that the fertility consequences of a single additional mating were small. We discuss this effect (or lack thereof), and suggest that it is likely to be attributed to small ejaculate size, a high proportion of failed copulations, and the presence of X-linked meiotic drive in this species

Current concepts in odontohypophosphatasia form of hypophosphatasia and report of two cases

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Shaping bursting by electrical coupling and noise

Gap-junctional coupling is an important way of communication between neurons and other excitable cells. Strong electrical coupling synchronizes activity across cell ensembles. Surprisingly, in the presence of noise synchronous oscillations generated by an electrically coupled network may differ qualitatively from the oscillations produced by uncoupled individual cells forming the network. A prominent example of such behavior is the synchronized bursting in islets of Langerhans formed by pancreatic \beta-cells, which in isolation are known to exhibit irregular spiking. At the heart of this intriguing phenomenon lies denoising, a remarkable ability of electrical coupling to diminish the effects of noise acting on individual cells. In this paper, we derive quantitative estimates characterizing denoising in electrically coupled networks of conductance-based models of square wave bursting cells. Our analysis reveals the interplay of the intrinsic properties of the individual cells and network topology and their respective contributions to this important effect. In particular, we show that networks on graphs with large algebraic connectivity or small total effective resistance are better equipped for implementing denoising. As a by-product of the analysis of denoising, we analytically estimate the rate with which trajectories converge to the synchronization subspace and the stability of the latter to random perturbations. These estimates reveal the role of the network topology in synchronization. The analysis is complemented by numerical simulations of electrically coupled conductance-based networks. Taken together, these results explain the mechanisms underlying synchronization and denoising in an important class of biological models

Secure optical communication using symbol-by-symbol time-domain spectral phase encoding with QPSK modulation

© Asia Communications and Photonics Conference (ACP) OSA 2019 We report the experimental demonstration of a secure optical communication system using 40 Gbps coherent quadrature phase shift keying modulation. The security is implemented in physical layer using symbol-by-symbol time domain spectral phase encoding.EPSRC Quantum Technology Hub in Quantum Communications (reference EP/M013472/1)

Long-time Low-latency Quantum Memory by Dynamical Decoupling

Quantum memory is a central component for quantum information processing devices, and will be required to provide high-fidelity storage of arbitrary states, long storage times and small access latencies. Despite growing interest in applying physical-layer error-suppression strategies to boost fidelities, it has not previously been possible to meet such competing demands with a single approach. Here we use an experimentally validated theoretical framework to identify periodic repetition of a high-order dynamical decoupling sequence as a systematic strategy to meet these challenges. We provide analytic bounds-validated by numerical calculations-on the characteristics of the relevant control sequences and show that a "stroboscopic saturation" of coherence, or coherence plateau, can be engineered, even in the presence of experimental imperfection. This permits high-fidelity storage for times that can be exceptionally long, meaning that our device-independent results should prove instrumental in producing practically useful quantum technologies.Comment: abstract and authors list fixe

Quadratic Word Equations with Length Constraints, Counter Systems, and Presburger Arithmetic with Divisibility

Word equations are a crucial element in the theoretical foundation of constraint solving over strings, which have received a lot of attention in recent years. A word equation relates two words over string variables and constants. Its solution amounts to a function mapping variables to constant strings that equate the left and right hand sides of the equation. While the problem of solving word equations is decidable, the decidability of the problem of solving a word equation with a length constraint (i.e., a constraint relating the lengths of words in the word equation) has remained a long-standing open problem. In this paper, we focus on the subclass of quadratic word equations, i.e., in which each variable occurs at most twice. We first show that the length abstractions of solutions to quadratic word equations are in general not Presburger-definable. We then describe a class of counter systems with Presburger transition relations which capture the length abstraction of a quadratic word equation with regular constraints. We provide an encoding of the effect of a simple loop of the counter systems in the theory of existential Presburger Arithmetic with divisibility (PAD). Since PAD is decidable, we get a decision procedure for quadratic words equations with length constraints for which the associated counter system is \emph{flat} (i.e., all nodes belong to at most one cycle). We show a decidability result (in fact, also an NP algorithm with a PAD oracle) for a recently proposed NP-complete fragment of word equations called regular-oriented word equations, together with length constraints. Decidability holds when the constraints are additionally extended with regular constraints with a 1-weak control structure.Comment: 18 page

Serum levels of WNT1-inducible signaling pathway protein-1 (WISP-1): a noninvasive biomarker of renal fibrosis in subjects with chronic kidney disease

WNT1-inducible signaling pathway protein-1 (WISP-1) is an extracellular matrix-related protein that plays multiple roles in cellular physiology and pathology. Accumulating evidence shows that WISP-1 is involved in the process underlying fibrotic diseases. However, the correlation between WISP-1 and renal fibrosis is unknown. In this study, we hypothesized that WISP-1 levels might be correlated with renal fibrosis and could be used as a noninvasive biomarker to screen for renal fibrosis in patients with chronic kidney disease (CKD). We first measured the WISP-1 expression levels using a transforming growth factor-β (TGF-β)-induced renal fibrosis tubular epithelial cell (TEC) model and a mouse model of obstructive nephropathy. We then evaluated the correlation between serum WISP-1 levels and fibrosis scores in biopsy-proven renal fibrosis of patients with CKD. Based on the findings from both in vivo and in vitro studies, the levels of WISP-1 and fibrotic parameters (collagen I, fibronectin and α-smooth muscle actin) were significantly increased in the fibrotic models. Consistently, patients with focal proliferative IgA nephropathy, focal segmental glomerular sclerosis and diabetic nephropathy displayed markedly elevated serum WISP-1 levels and fibrosis scores of renal biopsies compared with normal subjects and patients with minimal change disease (P<0.05). Importantly, the serum WISP-1 levels were positively correlated with fibrosis scores in the renal biopsies of these patients (r=0.475, P=0.0001). Thus, serum WISP-1 levels may be used as a potential noninvasive biomarker of renal fibrosis in patients with CKD.published_or_final_versio