Terahertz diffuse reflectors and their effects on group delay dispersion and communication performance

Engineered terahertz diffuse reflectors were created using mixtures of paint and varying amounts of aluminum powder to improve the reflectivity and scattering properties of surfaces. The performance of these reflectors is measured and analyzed using broadband terahertz spectroscopy. The effects of temporal dispersion caused by rough surface reflections on wireless terahertz communication is quantified and predicted using communication simulations. A scattering model using stochastic methods is used to describe rough surfaces, including the effects group delay dispersion caused by rough surface reflections. This model was validated using broadband terahertz spectroscopy to compare measured and simulated results. The modeled channel transfer function was used in a quadrature phase shift keyed (QPSK) communication simulation to find the expected symbol error rate with respect to surface roughness. Based on these simulations, a distinct dispersion limit in which group delay dispersion from rough surface reflections begins to cause symbol errors is found

Robertson-Walker fluid sources endowed with rotation characterised by quadratic terms in angular velocity parameter

Einstein's equations for a Robertson-Walker fluid source endowed with rotation Einstein's equations for a Robertson-Walker fluid source endowed with rotation are presented upto and including quadratic terms in angular velocity parameter. A family of analytic solutions are obtained for the case in which the source angular velocity is purely time-dependent. A subclass of solutions is presented which merge smoothly to homogeneous rotating and non-rotating central sources. The particular solution for dust endowed with rotation is presented. In all cases explicit expressions, depending sinusoidally on polar angle, are given for the density and internal supporting pressure of the rotating source. In addition to the non-zero axial velocity of the fluid particles it is shown that there is also a radial component of velocity which vanishes only at the poles. The velocity four-vector has a zero component between poles

Soil moisture monitoring with LoRa radios and UAVs

Oklahoma Established Program to Stimulate Competitive Research (National Science Foundation). Research Experiences for UndergraduatesGeological Survey (U.S.)Electrical Engineerin

Eomesodermin Requires Transforming Growth Factor-β/Activin Signaling and Binds Smad2 to Activate Mesodermal Genes*

The T-box gene Eomesodermin (Eomes) is required for early embryonic mesoderm differentiation in mouse, frog (Xenopus laevis), and zebrafish, is important in late cardiac development in Xenopus, and for CD8+ T effector cell function in mouse. Eomes can ectopically activate many mesodermal genes. However, the mechanism by which Eomes activates transcription of these genes is poorly understood. We report that Eomes protein interacts with Smad2 and is capable of working in a non-cell autonomous manner via transfer of Eomes protein between adjacent embryonic cells. Blocking of Eomes protein transfer using a farnesylated red fluorescent protein (CherryF) also prevents Eomes nuclear accumulation. Transfer of Eomes protein between cells is mediated by the Eomes carboxyl terminus (456-692). A carbohydrate binding domain within the Eomes carboxyl-terminal region is sufficient for transfer and important for gene activation. We propose a novel mechanism by which Eomes helps effect a cellular response to a morphogen gradient

Isotopic compositions of cometary matter returned by Stardust

Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme isotopic anomalies are rare, indicating that the comet is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen and neon isotope ratios suggest that indigenous organic matter and highly volatile materials were successfully collected. Except for a single O-17-enriched circumstellar stardust grain, silicate and oxide minerals have oxygen isotopic compositions consistent with solar system origin. One refractory grain is O-16-enriched, like refractory inclusions in meteorites, suggesting that Wild 2 contains material formed at high temperature in the inner solar system and transported to the Kuiper belt before comet accretion

Isotopic Compositions of Comentary Matter Returned by Stardust

Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme isotopic anomalies are rare, indicating that the comet is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen and neon isotope ratios suggest that indigenous organic matter and highly volatile materials were successfully collected. Except for a single17O-enriched circumstellar stardust grain, silicate and oxide minerals have oxygen isotopic compositions consistent with solar system origin. One refractory grain is16O-enriched, like refractory inclusions in meteorites, suggesting that Wild 2 contains material formed at high temperature in the inner solar system and transported to the Kuiper belt before comet accretion

Brachyury and SMAD signalling collaboratively orchestrate distinct mesoderm and endoderm gene regulatory networks in differentiating human embryonic stem cells

The transcription factor brachyury (T, BRA) is one of the first markers of gastrulation and lineage specification in vertebrates. Despite its wide use and importance in stem cell and developmental biology, its functional genomic targets in human cells are largely unknown. Here, we use differentiating human embryonic stem cells to study the role of BRA in activin A-induced endoderm and BMP4-induced mesoderm progenitors. We show that BRA has distinct genome-wide binding landscapes in these two cell populations, and that BRA interacts and collaborates with SMAD1 or SMAD2/3 signalling to regulate the expression of its target genes in a cell-specific manner. Importantly, by manipulating the levels of BRA in cells exposed to different signalling environments, we demonstrate that BRA is essential for mesoderm but not for endoderm formation. Together, our data illuminate the function of BRA in the context of human embryonic development and show that the regulatory role of BRA is context dependent. Our study reinforces the importance of analysing the functions of a transcription factor in different cellular and signalling environments

Cantu syndrome is caused by mutations in ABCC9

Item does not contain fulltextCantu syndrome is a rare disorder characterized by congenital hypertrichosis, neonatal macrosomia, a distinct osteochondrodysplasia, and cardiomegaly. Using an exome-sequencing approach applied to one proband-parent trio and three unrelated single cases, we identified heterozygous mutations in ABCC9 in all probands. With the inclusion of the remaining cohort of ten individuals with Cantu syndrome, a total of eleven mutations in ABCC9 were found. The de novo occurrence in all six simplex cases in our cohort substantiates the presence of a dominant disease mechanism. All mutations were missense, and several mutations affect Arg1154. This mutation hot spot lies within the second type 1 transmembrane region of this ATP-binding cassette transporter protein, which may suggest an activating mutation. ABCC9 encodes the sulfonylurea receptor (SUR) that forms ATP-sensitive potassium channels (K(ATP) channels) originally shown in cardiac, skeletal, and smooth muscle. Previously, loss-of-function mutations in this gene have been associated with idiopathic dilated cardiomyopathy type 10 (CMD10). These findings identify the genetic basis of Cantu syndrome and suggest that this is a new member of the potassium channelopathies