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Rate of photosynthetic induction in fluctuating light varies widely among genotypes of wheat.
Crop photosynthesis and yield are limited by slow photosynthetic induction in sunflecks. We quantified variation in induction kinetics across diverse genotypes of wheat for the first time. Following a preliminary study that hinted at wide variation in induction kinetics across 58 genotypes, we grew 10 genotypes with contrasting responses in a controlled environment and quantified induction kinetics of carboxylation capacity (Vcmax) from dynamic A versus ci curves after a shift from low to high light (from 50 µmol m-2 s-1 to 1500 µmol m-2 s-1), in five flag leaves per genotype. Within-genotype median time for 95% induction (t95) of Vcmax varied 1.8-fold, from 5.2 min to 9.5 min. Our simulations suggest that non-instantaneous induction reduces daily net carbon gain by up to 15%, and that breeding to speed up Vcmax induction in the slowest of our 10 genotypes to match that in the fastest genotype could increase daily net carbon gain by up to 3.4%, particularly for leaves in mid-canopy positions (cumulative leaf area index ≤1.5 m2 m-2), those that experience predominantly short-duration sunflecks, and those with high photosynthetic capacities
Optical studies of two LMC X-ray transients : RX J0544.1-7100 and RX J0520.5-6932
We report observations which confirm the identities of the optical
counterpart to the transient sources RX J0544.1-7100 and RX J0520.5-6932. The
counterparts are suggested to be a B-type stars. Optical data from the
observations carried out at ESO and SAAO, together with results from the OGLE
data base, are presented. In addition, X-ray data from the RXTE all-sky monitor
are investigated for long term periodicities. A strong suggestion for a binary
period of 24.4d is seen in RX J0520.5-6932 from the OGLE data.Comment: 6 pages, 7 figure
Exploring emotions and cognitions in hoarding: a Q-methodology analysis
Background:
The cognitions and emotions of people prone to hoarding are key components of the dominant cognitive behavioural model of hoarding disorder.
Aims:
This study sought to use Q-methodology to explore the thoughts and feelings of people that are prone to hoarding, to identify whether distinct clusters of participants could be found.
Method:
A 49-statement Q-set was generated following thematic analysis of initial interviews (n = 2) and a review of relevant measures and literature. Forty-one participants with problematic hoarding met various study inclusion criteria and completed the Q-sort (either online or offline). A by-person factor analysis was conducted and subsequent participant clusters compared on psychometric measures of mood, anxiety, hoarding and time taken on the online task as proxy for impulsivity.
Results:
Four distinct participant clusters were found constituting 34/41 (82.92%) of the participants, as the Q-sorts of n = 7 participants failed to cluster. The four clusters found were ‘overwhelmed’ (n = 11 participants); ‘aware of consequences’ (n = 13 participants); ‘object complexity’ (n = 6 participants) and ‘object–affect fusion’ (n = 4 participants). The clusters did not markedly differ with regard to hoarding severity, anxiety, depression or impulsivity.
Conclusions:
Whilst the participant clusters reflect extant research evidence, they also reveal significant heterogeneity and so prompt the need for further research investigating emotional and cognitive differences between people prone to hoarding
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Attributes of Society of Genitourinary Reconstructive Surgeons Fellows and Early Career Trajectory of the Recent Graduates
The polar ring galaxy AM1934-563 revisited
We report long-slit spectroscopic observations of the dust-lane polar-ring
galaxy AM1934-563 obtained with the Southern African Large Telescope (SALT)
during its performance-verification phase. The observations target the spectral
region of the Ha, [NII] and [SII] emission-lines, but show also deep NaI
stellar absorption lines that we interpret as produced by stars in the galaxy.
We derive rotation curves along the major axis of the galaxy that extend out to
about 8 kpc from the center for both the gaseous and the stellar components,
using the emission and absorption lines. We derive similar rotation curves
along the major axis of the polar ring and point out differences between these
and the ones of the main galaxy. We identify a small diffuse object visible
only in Ha emission and with a low velocity dispersion as a dwarf HII galaxy
and argue that it is probably metal-poor. Its velocity indicates that it is a
fourth member of the galaxy group in which AM1934-563 belongs. We discuss the
observations in the context of the proposal that the object is the result of a
major merger and point out some observational discrepancies from this
explanation. We argue that an alternative scenario that could better fit the
observations may be the slow accretion of cold intergalactic gas, focused by a
dense filament of galaxies in which this object is embedded (abridged).Comment: 19 pages, 13 figures, submitted to MNRAS. Some figures were bitmapped
to reduce the size. Full resolution version is available from
http://www.saao.ac.za/~akniazev/pub/AM1934_563.pd
Enzymatic synthesis of L-pipecolic acid and L-proline
This article does not have an abstract
A population-based approach to background discrimination in particle physics
Background properties in experimental particle physics are typically
estimated using control samples corresponding to large numbers of events. This
can provide precise knowledge of average background distributions, but
typically does not consider the effect of fluctuations in a data set of
interest. A novel approach based on mixture model decomposition is presented as
a way to estimate the effect of fluctuations on the shapes of probability
distributions in a given data set, with a view to improving on the knowledge of
background distributions obtained from control samples. Events are treated as
heterogeneous populations comprising particles originating from different
processes, and individual particles are mapped to a process of interest on a
probabilistic basis. The proposed approach makes it possible to extract from
the data information about the effect of fluctuations that would otherwise be
lost using traditional methods based on high-statistics control samples. A
feasibility study on Monte Carlo is presented, together with a comparison with
existing techniques. Finally, the prospects for the development of tools for
intensive offline analysis of individual events at the Large Hadron Collider
are discussed.Comment: Updated according to the version published in J. Phys.: Conf. Ser.
Minor changes have been made to the text with respect to the published
article with a view to improving readabilit
Coherent Heteroepitaxy of Bi2Se3 on GaAs (111)B
We report the heteroepitaxy of single crystal thin films of Bi2Se3 on the
(111)B surface of GaAs by molecular beam epitaxy. We find that Bi2Se3 grows
highly c-axis oriented, with an atomically sharp interface with the GaAs
substrate. By optimizing the growth of a very thin GaAs buffer layer before
growing the Bi2Se3, we demonstrate the growth of thin films with atomically
flat terraces over hundreds of nanometers. Initial time-resolved Kerr rotation
measurements herald opportunities for probing coherent spin dynamics at the
interface between a candidate topological insulator and a large class of
GaAs-based heterostructures.Comment: To appear in Applied Physics Letter
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