A selected ion flow tube study of the reactions of gas-phase cations with PSCl3

A selected ion flow tube was used to investigate the positive ion chemistry of thiophosphoryl chloride, PSCl$_3$. Rate coefficients and ion product branching ratios have been determined at room temperature for reactions with nineteen cations ; H$_3$O$^+$, CF$_3^+$, CF$^+$, NO$^+$, NO$_2^+$, SF$_2^+$, SF$^+$, CF$_2^+$, O$_2^+$, H$_2$O$^+$, N$_2$O$^+$, O$^+$, CO$_2^+$, CO$^+$, N$^+$, N$_2^+$, Ar$^+$, F$^+$ and Ne$^+$ (in order of increasing recombination energy). Complementary data described in the previous paper have been obtained for this molecule via the observation of threshold photoelectron photoion coincidences. For ions whose recombination energies are in the range 10-22 eV, comparisons are made between the product ion branching rations of PSCl$_3$ from photoionisation and from ion-molecule reactions. In most instances, the data from the two experiments are well correlated, suggesting that long-range charge transfer is the dominant mechanism for these ion-molecule reactions ; the agreement is particularly good for the atomic ions Ar$^+$, F$^+$ and Ne$^+$. Some reactions (e.g. O$_2^+$ + PSCl$_3$), however, exhibit significant differences; short-range charge transfer must then be occurring following the formation of an ion-molecule complex. For ions whose recombination energies are less than 10 eV (i.e. H$_3$O$^+$, CF$_3^+$, CF$^+$ and NO$^+$), reactions can only occur via a chemical process in which bonds are broken and formed, because the recombination energy of the cation is less than the ionisation energy of PSCl$_3$

Tillage investigations.

77A16, red/brown sandy loam - York gum. 77WH17, yellow clayey-sand (Wongan loamy sand). 77M13, red sandy clay loam (Salmon Gum, Gimlet). 77Mt15, gravelly loamy sand/sandy loam - forest soil. 77A43 brown loamy sand/sandy loam - jam country. 77WH88, grey loamy sand over gravel at 50 cm - Elphin soil series – Mallee. 77M56, red sandy clay loam - salmon gum, Gimlet. 82M35, Loamy sand/sandy loam – Mallee. 77E52, fine white sand over gravel at 40 cm. 85SG28, grey-brown calcareous Earth - Kumarl – SGRS. 84M064, heavy land management systems - medium rainfall area. 84M063, heavy land management systems - ne wheat belt - continuous wheat additional heavy land long term direct drill trials, 84KA28. Minimum tillage, direct drilling, modified combine investigations. 87E35, White Grey Fleming Sandplain over gravel varying from 20 40 cm. 87E36, Fleming Sandplain Alongside 87E35. 87E37, Fleming Sandplain near E35, 36. 87M76, 87M77 Depth of cultivation with modified combine, and deep ripping. 87WH52 Wongan Loamy Sand - Depth of cultivation during Seeding, and Deep Ripping. 87Na81, 87Na 84 cultivate, direct drill, and speed of seeding. 86SG27, direct drilling, reduced tillage and conventional at two times of seeding with and without flexi coil. 87WH45, direct drill, scarifying, disc ploughing, chisel ploughing at two depths and deep ripping. 79WH6, grey and yellow loamy sand with gravel. 79M7, yellow loamy sand - Mallee scrub 82M34, salmon gum/gimlet clay loam. 84M1, stubble effect on heavy land - salmon gum soil – MRS. 85Ba32, deep ripping yellow sand/yellow loamy sand – BARS. 886LG67, 886LG68, DD scarifying and depth of ripping 2GE37, 82GE38, yellow sandplain - Naraling lupin/wheat rotation (2 blocks). 82M60, Semi Wodgil - MRS old lease block. 87M5, species and cultivar response to deep ripping on acidic yellow sandplain. 87M78, ripping, two times of seeding, three wheat varieties - Mallee soil, MRS. 86Mo28 Cultivation and Gypsum on Hard Setting Clay Loam - A. Tonkin, Coomberdale. 87Mo1, 87Mo2, 87Mo3, deep ripping on sands in the Minyulo Brook catchment west of Moora - Farmers Brennan and Edgar. 87SG31, Circle Valley and over clay. Pasture. 77WH17, yellow clayey sand (Wongan loamy sand). 82WH49, times of ripping in a 2 pasture: 2 wheat rotation - Wongan loamy sand. 84WH39, two machines at two speeds of ripping - Wongan loamy sand. 85WH41, depth of ripping by shank spacing. 85WH62, depth of ripping by shank spacing - Wongan loamy sand. 86WH4, two times of seeding, with and without ripping, 7 rates of nitrogen, one rate N applied late. 86WH43, deep ripping response by wheat and barley varieties - Wongan loamy sand. 86WH66, time of ripping, pre and post seeding - Wongan loamy sand. 87WH55, ripping times pre and post seeding with two seeding rates. MISCELLANEOUS TRIALS. 86M79, fallowing and deep ripping with two times of seeding on sandy clay loam. 87M2, banding superphosphate at depths below the seed - Newland, yellow sandplain, Carrabin - Jarvis and Bolland. 81SG1, Kumarl soil - SGRS - crop/fallow rotation. 87SG32 and 87SG33, rate of seeding-wheat on Kumarl soil

Long term minimum tillage investigations, stubble management techniques, deep ripping and seeding machine comparisons.

77 A 16, red/brown sandy loam. 77 WH 17, yellow clayey-sand (Wongan loamy sand). 77 M 13, red sandy clay loam (salmon gum, gimlet). 78 M 25, Yellow acid loamy sand (Wodgil). 77 Mt 15 Gravelly loamy sand/sandy loam - forest soil 77 E 18, fine white sand over fine sandy clay. 77 A 43, Brown loamy sand/sandy loam - Jam country.77 WH 88, Grey loamy sand over gravel at 50 cm - Elphin soil series – Mallee. 77 M 56, Red sandy clay loam - Salmon Gum, Gimlet. 82 M 35, Loamy sand/sandy loam – Mallee. 77 E 52, Fine white sand over gravel at 40 cm. 85 SG 28, Grey-brown calcareous earth - Kumarl – SGRS. 77 Mt 51, Gravelly sandy loam - forest soil. 79 WH 6, Grey and yellow loamy sand with gravel. 79 M 7, Yellow loamy sand - Mallee scrub. 82 M 34, Salmon Gum/Gimlet clay loam. 84 M 1, Stubble effect on heavy land - Salmon Gum soil – MRS. 82 M 35, deep ripping. 82 GE 37, 82 GE 38, Yellow sandplain - Naraling - Lupin/Wheat Rotation. 84 C 72, Eradu Sandplain – ECRS. 85 C 84, Eradu Sandplain ECRS. 77 WH 17, Yellow clayey sand (Wongan loamy sand). 84 WH 2, Species response to ripping - Wongan loamy sand - residual effects. 84 WH 3 - ripping and re-compaction of ripped soil - Wongan loamy sand. 85 WH 36, 85 WH 37, 85 WH 38, 85 WH 39, deep ripping four soil types – WHRS. 85 WH 40, deep ripping and scarifying comparisons with direct drill on four soil types. 85 WH 41, depth of ripping by shank spacing. 82 Mo30, yellow loamy sand - Dalwallinu - Taywood farms. 79 MO 19, deep ripping in a pasture/wheat rotation - heavy land - Nixon, Kalannie. 81 M 53, yellow loamy sand - Mallee/Wodgil – MRS. 82 Me 38, Residual effect of deep ripping in pasture/wheat/lupin rotation, yellow loamy sand – Koorda. 85 Me 57, 85 Me 58, 85 Me 59, 85 Me 60, 85 Me 61, 85 Me 62, ripping responses on paddocks with different cropping histories Crosthwaite, Holleton. 80 NO 46, yellow loamy sand - Tamma - R. Reid, Yorkrakine. 83 NO 69, yellow loamy sand - Tamma - Reid, Yorkrakine. 82 NO 48, 82 NO 49, yellow loamy sand - Tamma – Yorkrakine. 84 Ba 32, deep ripping yellow sand/yellow loamy sand – BARS. 85 Ba 33, deep ripping white sand/pale yellow sand – BARS. 85 Ba 4la, deep ripping and scarifying comparisons with direct drill on different soil types. 85 Ba 4lb, deep ripping and nutrition - deep very poor white sand – BARS. 84 E 24, deep white sand over gravel – EDRS. 85 E 29, cultivation depths and direct drilling machines - deep white sand – EDRS. 85 E 30, deep ripping and scarifying on Caitup soil – EDRS. 85 E 31, deep ripping and scarifying comparison with direct drill on four soil types. 85 TS 39, yellow sand/loamy sand, R and D Nottle, West Three Springs. Deep ripping pasture – Denbarker. 85 WH 42, yellow loamy sand – WHRS. 85 WH 43, yellow loamy sand – WHRS. 85 WH 44, yellow loamy sand – WHRS

Adult beginner distance language learner perceptions and use of assignment feedback

This qualitative study examines perceptions and use of assignment feedback among adult beginner modern foreign language learners on higher education distance learning courses. A survey of responses to feedback on assignments by 43 Open University students on beginner language courses in Spanish, French, and German indicated that respondents can be classified into three groups: those who use feedback strategically by integrating it into the learning process and comparing it with, for example, informal feedback from interaction with native speakers, those who take note of feedback, but seem not to use it strategically, and those who appear to take little account of either marks or feedback. The first group proved to be the most confident and most likely to maintain their motivation in the longer term. The conclusion discusses some of the pedagogical and policy implications of the findings

Constraints on early dark energy from CMB lensing and weak lensing tomography

Dark energy can be studied by its influence on the expansion of the Universe as well as on the growth history of the large-scale structure. In this paper, we follow the growth of the cosmic density field in early dark energy cosmologies by combining observations of the primary CMB temperature and polarisation power spectra at high redshift, of the CMB lensing deflection field at intermediate redshift and of weak cosmic shear at low redshifts for constraining the allowed amount of early dark energy. We present these forecasts using the Fisher-matrix formalism and consider the combination of Planck-data with the weak lensing survey of Euclid. We find that combining these data sets gives powerful constraints on early dark energy and is able to break degeneracies in the parameter set inherent to the various observational channels. The derived statistical 1-sigma-bound on the early dark energy density parameter is sigma(Omega_d^e)=0.0022 which suggests that early dark energy models can be well examined in our approach. In addition, we derive the dark energy figure of merit for the considered dark energy parameterisation and comment on the applicability of the growth index to early dark energy cosmologies.Comment: 25 pages, 14 figures, 3 tables; v2: very minor additions, updated to match version to be published in JCA

Nanoscale Mechanical Characterisation of Amyloid Fibrils Discovered in a Natural Adhesive

Using the atomic force microscope, we have investigated the nanoscale mechanical response of the attachment adhesive of the terrestrial alga Prasiola linearis (Prasiolales, Chlorophyta). We were able to locate and extend highly ordered mechanical structures directly from the natural adhesive matrix of the living plant. The in vivo mechanical response of the structured biopolymer often displayed the repetitive sawtooth force-extension characteristics of a material exhibiting high mechanical strength at the molecular level. Mechanical and histological evidence leads us to propose a mechanism for mechanical strength in our sample based on amyloid fibrils. These proteinaceous, pleated β-sheet complexes are usually associated with neurodegenerative diseases. However, we now conclude that the amyloid protein quaternary structures detected in our material should be considered as a possible generic mechanism for mechanical strength in natural adhesives

Weak lensing, dark matter and dark energy

Weak gravitational lensing is rapidly becoming one of the principal probes of dark matter and dark energy in the universe. In this brief review we outline how weak lensing helps determine the structure of dark matter halos, measure the expansion rate of the universe, and distinguish between modified gravity and dark energy explanations for the acceleration of the universe. We also discuss requirements on the control of systematic errors so that the systematics do not appreciably degrade the power of weak lensing as a cosmological probe.Comment: Invited review article for the GRG special issue on gravitational lensing (P. Jetzer, Y. Mellier and V. Perlick Eds.). V3: subsection on three-point function and some references added. Matches the published versio

Cosmological parameters from SDSS and WMAP

We measure cosmological parameters using the three-dimensional power spectrum P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in combination with WMAP and other data. Our results are consistent with a ``vanilla'' flat adiabatic Lambda-CDM model without tilt (n=1), running tilt, tensor modes or massive neutrinos. Adding SDSS information more than halves the WMAP-only error bars on some parameters, tightening 1 sigma constraints on the Hubble parameter from h~0.74+0.18-0.07 to h~0.70+0.04-0.03, on the matter density from Omega_m~0.25+/-0.10 to Omega_m~0.30+/-0.04 (1 sigma) and on neutrino masses from <11 eV to <0.6 eV (95%). SDSS helps even more when dropping prior assumptions about curvature, neutrinos, tensor modes and the equation of state. Our results are in substantial agreement with the joint analysis of WMAP and the 2dF Galaxy Redshift Survey, which is an impressive consistency check with independent redshift survey data and analysis techniques. In this paper, we place particular emphasis on clarifying the physical origin of the constraints, i.e., what we do and do not know when using different data sets and prior assumptions. For instance, dropping the assumption that space is perfectly flat, the WMAP-only constraint on the measured age of the Universe tightens from t0~16.3+2.3-1.8 Gyr to t0~14.1+1.0-0.9 Gyr by adding SDSS and SN Ia data. Including tensors, running tilt, neutrino mass and equation of state in the list of free parameters, many constraints are still quite weak, but future cosmological measurements from SDSS and other sources should allow these to be substantially tightened.Comment: Minor revisions to match accepted PRD version. SDSS data and ppt figures available at http://www.hep.upenn.edu/~max/sdsspars.htm

The Milky Way Bulge: Observed properties and a comparison to external galaxies

The Milky Way bulge offers a unique opportunity to investigate in detail the role that different processes such as dynamical instabilities, hierarchical merging, and dissipational collapse may have played in the history of the Galaxy formation and evolution based on its resolved stellar population properties. Large observation programmes and surveys of the bulge are providing for the first time a look into the global view of the Milky Way bulge that can be compared with the bulges of other galaxies, and be used as a template for detailed comparison with models. The Milky Way has been shown to have a box/peanut (B/P) bulge and recent evidence seems to suggest the presence of an additional spheroidal component. In this review we summarise the global chemical abundances, kinematics and structural properties that allow us to disentangle these multiple components and provide constraints to understand their origin. The investigation of both detailed and global properties of the bulge now provide us with the opportunity to characterise the bulge as observed in models, and to place the mixed component bulge scenario in the general context of external galaxies. When writing this review, we considered the perspectives of researchers working with the Milky Way and researchers working with external galaxies. It is an attempt to approach both communities for a fruitful exchange of ideas.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen E., Peletier R., Gadotti D., Springer Publishing. 36 pages, 10 figure

The LOFAR Two Meter Sky Survey: Deep Fields, I -- Direction-dependent calibration and imaging

The Low Frequency Array (LOFAR) is an ideal instrument to conduct deep extragalactic surveys. It has a large field of view and is sensitive to large-scale and compact emission. It is, however, very challenging to synthesize thermal noise limited maps at full resolution, mainly because of the complexity of the low-frequency sky and the direction dependent effects (phased array beams and ionosphere). In this first paper of a series, we present a new calibration and imaging pipeline that aims at producing high fidelity, high dynamic range images with LOFAR High Band Antenna data, while being computationally efficient and robust against the absorption of unmodeled radio emission. We apply this calibration and imaging strategy to synthesize deep images of the Boötes and Lockman Hole fields at ∼150 MHz, totaling ∼80 and ∼100 h of integration, respectively, and reaching unprecedented noise levels at these low frequencies of .30 and .23 µJy beam−1 in the inner ∼3 deg2 . This approach is also being used to reduce the LOTSS-wide data for the second data release