Crustal deformation at the Sumatran Subduction Zone revealed by coral rings

Analyses of coral rings grown in the interval 1970–1997 reveal a geographically distinct pattern of interseismic uplift off Sumatra's western coast. At distances less than 110 km from the Sumatran trench, coral reefs are submerging as fast as 5 mm/y. At 130 and 180 km distance from the trench, they are emerging at similar rates. We suggest that a locked, or partially locked patch, located above 30 km depth on the upper surface of the subducting oceanic plate, generates this pattern

Perturbation theory for anisotropic dielectric interfaces, and application to sub-pixel smoothing of discretized numerical methods

We derive a correct first-order perturbation theory in electromagnetism for cases where an interface between two anisotropic dielectric materials is slightly shifted. Most previous perturbative methods give incorrect results for this case, even to lowest order, because of the complicated discontinuous boundary conditions on the electric field at such an interface. Our final expression is simply a surface integral, over the material interface, of the continuous field components from the unperturbed structure. The derivation is based on a "localized" coordinate-transformation technique, which avoids both the problem of field discontinuities and the challenge of constructing an explicit coordinate transformation by taking a limit in which a coordinate perturbation is infinitesimally localized around the boundary. Not only is our result potentially useful in evaluating boundary perturbations, e.g. from fabrication imperfections, in highly anisotropic media such as many metamaterials, but it also has a direct application in numerical electromagnetism. In particular, we show how it leads to a sub-pixel smoothing scheme to ameliorate staircasing effects in discretized simulations of anisotropic media, in such a way as to greatly reduce the numerical errors compared to other proposed smoothing schemes.Comment: 10 page

Gene Sequencing-Based Analysis of Microbial-Mat Morphotypes, Caicos Platform, British West Indies

Active carbonate platforms provide modern analogs to study microbial-mat development and taphonomy in the sedimentary record. Microbial-mat descriptions and classifications for tropical tidal-flat environments have focused predominantly on morphological observations. This is exemplified by flat and biscuit-shaped mats, where the mat morphotypes are postulated to reflect different Cyanobacteria communities as the main mat-building taxa. To compare the total microbial communities of these two mat types and test this Cyanobacteria hypothesis, we applied optical microscopy and gene sequencing methods using samples from a tidal algal marsh on Little Ambergris Cay, Turks and Caicos, B.W.I. With gene sequencing we find that total diversity and community composition differs significantly between morphotypes; the biscuit mat is more diverse than the flat mat. Microscopy results support that Cyanobacteria populations colonizing the surface layer of these two mat types are responsible for much of the mat's structural elements; however, genetic data find the Cyanobacteria population is indistinguishable between the two mat types. The recovered Cyanobacteria populations fall predominantly into three taxa: Scytonema, Halomicronema, and Crinalium. We propose that the morphology of these two mat types is not controlled by the Cyanobacteria, but instead reflects a time-integrated microbial response to environmental factors, where the microbial community becomes more diverse with time since environmental disturbance

Agreed definitions and a shared vision for new standards in stroke recovery research: The Stroke Recovery and Rehabilitation Roundtable taskforce.

The first Stroke Recovery and Rehabilitation Roundtable established a game changing set of new standards for stroke recovery research. Common language and definitions were required to develop an agreed framework spanning the four working groups: translation of basic science, biomarkers of stroke recovery, measurement in clinical trials and intervention development and reporting. This paper outlines the working definitions established by our group and an agreed vision for accelerating progress in stroke recovery research

A molecular communication channel consisting of a single reversible chain of hydrogen bonds in a conformationally flexible oligomer

Communication of information through the global switching of conformation in synthetic molecules has hitherto entailed the inversion of chirality. Here, we report a class of oligomer through which information may be communicated through a global reversal of polarity. Ethylene-bridged oligoureas are constitutionally symmetrical, conformationally flexible molecules organized by a single chain of hydrogen bonds running the full length of the oligomer. NMR reveals that this hydrogen-bonded chain may undergo a coherent reversal of directionality. The directional uniformity of the hydrogen-bond chain allows it to act as a channel for the spatial communication of information on a molecular scale. A binding site at the terminus of an oligomer detects local information about changes in pH or anion concentration and transmits that information—in the form of a directionality switch in the hydrogen-bond chain—to a remote polarity-sensitive fluorophore. This propagation of polarity-encoded information provides a new mechanism for molecular communication

Proteomic profiling of urine for the detection of colon cancer.

BACKGROUND: Colorectal cancer is the second most common cause of cancer related death in the developed world. To date, no blood or stool biomarkers with both high sensitivity and specificity for potentially curable early stage disease have been validated for clinical use. SELDI and MALDI profiling are being used increasingly to search for biomarkers in both blood and urine. Both techniques provide information predominantly on the low molecular weight proteome (<15 kDa). There have been several reports that colorectal cancer is associated with changes in the serum proteome that are detectable by SELDI and we hypothesised that proteomic changes would also be detectable in urine. RESULTS: We collected urine from 67 patients with colorectal cancer and 72 non-cancer control subjects, diluted to a constant protein concentration and generated MALDI and SELDI spectra. The intensities of 19 peaks differed significantly between cancer and non-cancer patients by both t-tests and after adjusting for confounders using multiple linear regressions. Logistic regression classifiers based on peak intensities identified colorectal cancer with up to 78% sensitivity at 87% specificity. We identified and independently quantified 3 of the discriminatory peaks using synthetic stable isotope peptides (an 1885 Da fragment of fibrinogen and hepcidin-20) or ELISA (beta2-microglobulin). CONCLUSION: Changes in the urine proteome may aid in the early detection of colorectal cancer

Reverse Biomimetic’ Synthesis of L-Arogenate and its Stabilized Analogues from L-Tyrosine

l-Arogenate (also known as l-pretyrosine) is a primary metabolite on a branch of the shikimate biosynthetic pathway to aromatic amino acids. It plays a key role in the synthesis of plant secondary metabolites including alkaloids and the phenylpropanoids that are the key to carbon fixation. Yet understanding the control of arogenate metabolism has been hampered by its extreme instability and the lack of a versatile synthetic route to arogenate and its analogues. We now report a practical synthesis of l-arogenate in seven steps from O-benzyl l-tyrosine methyl ester in an overall yield of 20%. The synthetic route also delivers the fungal metabolite spiroarogenate, as well as a range of stable saturated and substituted analogues of arogenate. The key step in the synthesis is a carboxylative dearomatization by intramolecular electrophilic capture of tyrosine's phenolic ring using an N-chloroformylimidazolidinone moiety, generating a versatile, functionalizable spirodienone intermediate

The Ionized Gas and Nuclear Environment in NGC 3783 V. Variability and Modeling of the Intrinsic Ultraviolet Absorption

We present results on the location, physical conditions, and geometry of the outflow in the Seyfert 1 galaxy NGC 3783 from a study of the variable intrinsic UV absorption. Based on 18 observations with HST/STIS and 6 observations with FUSE, we find: 1) The absorption from the lowest-ionization species in each of the three strong kinematic components varied inversely with the continuum flux, indicating the ionization structure responded to changes in the photoionizing flux over the weekly timescales sampled by our observations. 2) A multi- component model with an unocculted NLR and separate BLR and continuum line-of-sight covering factors predicts saturation in several lines, consistent with the lack of observed variability. 3) Column densities for the individual metastable levels are measured from the resolved C III *1175 absorption complex observed in one component. Based on our computed metastable level populations, the electron density of this absorber is ~3x10^4 cm^-3. Photoionization modeling results place it at ~25 pc from the central source. 4) Using time-dependent calculations, we are able to reproduce the detailed variability observed in this absorber, and derive upper limits on the distances for the other components of 25-50 pc. 5) The ionization parameters derived for the higher ionization UV absorbers are consistent with the modeling results for the lowest-ionization X-ray component, but with smaller total column density. They have similar pressures as the three X-ray ionization components. These results are consistent with an inhomogeneous wind model for the outflow in NGC 3783. 6) Based on the predicted emission-line luminosities, global covering factor constraints, and distances derived for the UV absorbers, they may be identified with emission- line gas observed in the inner NLR of AGNs. (abridged)Comment: 30 pages, 18 figures (7 color), emulateapj, accepted for publication in The Astrophysical Journa