Crystal structure of 3-benzoyl-2-[(5-bromo-2-Hydroxy-3-methoxybenzylidene)amino]-4,5,6,7-tetrahydrobenzo[b]thiophene

In the cyclo­hexene ring of the title compound, C23H20BrNO3S, the -(CH2)4- atoms are positionally disordered [occupancy ratio = 0.753 (6):0.247 (6)]. The ring has a half-chair conformation for both the major and minor components. The dihedral angles between the mean plane of the thio­phene ring and those of the benzene and phenyl rings are 35.2 (4) and 57.7 (3)°, respectively. The planes of the two aryl rings are twisted with respect to each other by 86.4 (6)°. In the mol­ecule, there is an O-H...N hydrogen bond forming an S(6) ring motif. In the crystal, mol­ecules are linked via C-H...O hydrogen bonds, forming chains parallel to [100].Publisher PDFPeer reviewe

Phosphorus recovery: a need for an integrated approach

Increasing cost of phosphate fertilizer, a scarcity of high quality phosphate rock (PR)and increasing surface water pollution are driving aneed to accelerate the recovery and re-use ofphosphorus (P) from various waste sectors. Options to recover P occur all along the open P cycle from mining to households to oceans. However, P recovery as a regional and global strategy towards P sustainability and future food, bio energy and water security is in its infancy because of a number of technological, socio-economic and institutional constraints. There is no single solution and resolving these constraints requires concerted collaboration betweenrelevant stakeholders and an integrated approach combiningsuccessful business models withsocio-economic and institutional change. We suggest that an operational framework is developed for fast tracking cost-effective recovery options

Acoustic Liner Drag: Further Measurements on Novel Facesheet Perforate Geometries

Over the past several years, the NASA Langley Liner Physics Team has worked to develop methods capable of characterizing the aerodynamic drag of acoustic liners in addition to their acoustic performance. For a given liner, one can compute its resistance factor, , based on static pressure drop measurements. The current study details experiments in the NASA Langley Grazing Flow Impedance Tube to quantify the relative drag of several perforate-over-honeycomb liner configurations at flow speeds of Mach 0.3 and 0.5. The liner facesheets incorporate novel perforate geometries rather than the conventional, round hole designs typically used. Measurements of the resistance factor for each liner are made with and without acoustic excitation. A tonal acoustic source is used at sound pressure levels of 140 and 150 dB over a frequency range of 400 to 3000 Hz when performing acoustic measurements. Educed impedance spectra are calculated to determine the impact of variations in perforate geometry on acoustic performance and the relationship between acoustic and drag performance

Time resolved spectroscopic investigation of SiD2 + D2: kinetic study

Silylenes (silanediyls) have made an important impact on organosilicon chemistry even if it is of more recent foundation than carbenes in organic chemistry and much less complete. These species are highly reactive intermediates. They play a central role in the chemical vapour deposition (CVD) of various silicon-containing thin films which have a technological importance in microelectronics as well as in the dry etching processes of silicon wafers. Spectroscopic methods have been developed to observe these species, a necessary pre-requisite to their direct monitoring. In this work, deuterated phenylsilane precursor, PhSiD3 was chosen for SiD2 because its analogue phenylsilane, PhSiH3 proved to be a good precursor for SiH2 and the high quality decay signals observed revealed that SiD2 be readily detected from PhSiD3 and that if other decomposition pathways (e.g. PhSiD + D2) are occurring, they do not effect measurements of the rate constants for SiD2. The absorption spectrum of SiD2 formed from the flash photolysis of a mixture of PhSiD3 and SF6 at 193nm were found in the region 17384-17391 cm-1 with strong band at 17387.07 cm-1. This single rotational line of pQ1 was chosen to monitor SiD2 removal. Time-resolved studies of SiD2 have been carried out to obtain rate constants for its bimolecular reactions with D2. The reactions were studied over the pressure range 5-100 Torr (in SF6 bath gas) at four temperatures in the range 298-498K. Single decay from 10 photolysis laser shots were averaged and found to give reasonable first-order kinetics fits. Second order kinetics were obtained by pressure dependence of the pseudo first order decay constants and substance D2 pressures within experimental error. The reaction was found to be weakly pressure dependent at all temperatures, consistent with a third-body mediated association process. In addition, SiH2+ H2 reaction is approximately ca. 60% faster than SiD2+D2 reaction. Theoretical extrapolations (using Lindemann-Hinshelwood model and Rice, Ramsperger, Kassel and Marcus (RRKM) theory) were also carried out and obtained data fitted the Arrhenius equations

Dimensional Effects on Solitonic Matter and Optical Waves with Normal and Anomalous Dispersion

We investigate bright and dark solitons with anomalous or normal dispersion and under transverse harmonic confinement. In matter waves, positive atomic mass implies anomalous dispersion (kinetic spreading) while negative mass gives normal dispersion (kinetic shrinking). We find that, contrary to the strictly one-dimensional case, the axial and transverse profiles of these solitons crucially depend on the strength of the nonlinearity and on their dispersive properties. In particular, we show that, like bright solitons with anomalous dispersion, also dark solitons with normal dispersion disappear at a critical axial density. Our predictions are useful for the study of atomic matter waves in Bose-Einstein condensates and also for optical bullets in inhomogeneous Kerr media.Comment: To be published in Journal of Physics B: At. Mol. Opt. Phy

Multiple feedback loops through cytokinin signaling control stem cell number within the Arabidopsis shoot meristem

A central unanswered question in stem cell biology, both in plants and in animals, is how the spatial organization of stem cell niches are maintained as cells move through them. We address this question for the shoot apical meristem (SAM) which harbors pluripotent stem cells responsible for growth of above-ground tissues in flowering plants. We find that localized perception of the plant hormone cytokinin establishes a spatial domain in which cell fate is respecified through induction of the master regulator WUSCHEL as cells are displaced during growth. Cytokinin-induced WUSCHEL expression occurs through both CLAVATA-dependent and CLAVATA-independent pathways. Computational analysis shows that feedback between cytokinin response and genetic regulators predicts their relative patterning, which we confirm experimentally. Our results also may explain how increasing cytokinin concentration leads to the first steps in reestablishing the shoot stem cell niche in vitro

Cassini plasma observations of Saturn's magnetospheric cusp

The magnetospheric cusp is a funnel-shaped region where shocked solar wind plasma is able to enter the high latitude magnetosphere via the process of magnetic reconnection. The plasma observations include various cusp signatures such as ion energy dispersions as well as diamagnetic effects. We present an overview analysis of the cusp plasma observations at the Saturnian magnetosphere from the Cassini spacecraft era. A comparison of the observations is made as well as classification into groups due to varying characteristics. The locations of the reconnection site are calculated and shown to vary along the subsolar magnetopause. We show the first in situ evidence for lobe reconnection that occurred at nearly the same time as dayside reconnection for one of the cusp crossings. Evidence for 'bursty' and more 'continous' reconnection signatures are observed in different cusp events. The events are compared to solar wind propagation models and it is shown that magnetic reconnection and plasma injection into the cusp can occur for a variety of upstream conditions. These are important results because they show that Saturn's magnetospheric interaction with the solar wind and the resulting cusp signatures are dynamic, and that plasma injection in the cusp occurs due to a variety of solar wind conditions. Furthermore, reconnection can proceed at a variety of locations along the magnetopause

Measurement of the charged-pion polarisability

The COMPASS collaboration at CERN has investigated pion Compton scattering, $\pi^-\gamma\rightarrow \pi^-\gamma$, at centre-of-mass energy below 3.5 pion masses. The process is embedded in the reaction $\pi^-\mathrm{Ni}\rightarrow\pi^-\gamma\;\mathrm{Ni}$, which is initiated by 190\,GeV pions impinging on a nickel target. The exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, $Q^2<0.0015$\,(GeV/$c$)$^2$. From a sample of 63\,000 events the pion electric polarisability is determined to be $\alpha_\pi\ =\ (\,2.0\ \pm\ 0.6_{\mbox{\scriptsize stat}}\ \pm\ 0.7_{\mbox{\scriptsize syst}}\,) \times 10^{-4}\,\mbox{fm}^3$under the assumption$\alpha_\pi=-\beta_\pi$, which relates the electric and magnetic dipole polarisabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction, that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is found in agreement with the expectation from chiral perturbation theory. An additional measurement replacing pions by muons, for which the cross-section behavior is unambigiously known, was performed for an independent estimate of the systematic uncertainty.Comment: Published version: 9 pages, 3 figures, 1 tabl

Measurement of the Longitudinal Spin Transfer to Lambda and Anti-Lambda Hyperons in Polarised Muon DIS

The longitudinal polarisation transfer from muons to lambda and anti-lambda hyperons, D_LL, has been studied in deep inelastic scattering off an unpolarised isoscalar target at the COMPASS experiment at CERN. The spin transfers to lambda and anti-lambda produced in the current fragmentation region exhibit different behaviours as a function of x and xF . The measured x and xF dependences of D^lambda_LL are compatible with zero, while D^anti-lambda_LL tends to increase with xF, reaching values of 0.4 - 0.5. The resulting average values are D^lambda_LL = -0.012 +- 0.047 +- 0.024 and D^anti-lambda_LL = 0.249 +- 0.056 +- 0.049. These results are discussed in the frame of recent model calculations.Comment: 13 pages, 7 figure