Improving competitive ability of chickpea with sowthistle

An experiment was conducted to examine the extent of root and canopy interference of chickpea (Cicer arietinum L.) with sowthistle (Sonchus oleraceus L.). Sowthistle was surrounded with either two or eight chickpea plants. There were different types of competition: no competition, shoot competition, root competition and full competition (root and shoot). The performance of sowthistle grown in full competition with two chickpea plants was the same as that grown with root competition only. Also, there were no significant differences between sowthistle grown with chickpea canopy shade and the control, where there was no competition. On the other hand sowthistle grown with eight neighbours was significantly suppressed in full, canopy or root competition

The Eclipsing δ\delta Scuti Star EPIC 245932119

We present the physical properties of EPIC 245932119 ($K_{\rm p}$ = $+$9.82) exhibiting both eclipses and pulsations from the {\it K{\rm 2}} photometry. The binary modeling indicates that the eclipsing system is in detached or semi-detached configurations with a mass ratio of 0.283 or 0.245, respectively, and that its light-curve parameters are almost unaffected by pulsations. Multiple frequency analyses were performed for the light residuals in the outside-primary eclipsing phase after subtracting the binarity effects from the observed data. We detected 35 frequencies with signal to noise amplitude ratios larger than 4.0 in two regions of 0.62$-$6.28 day$^{-1}$ and 19.36$-$24.07 day$^{-1}$. Among these, it is possible that some high signals close to the Nyquist limit $f_{\rm Ny}$ may be reflections of real pulsation frequencies (2$f_{\rm Ny}-f_i$). All frequencies ($f_8$, $f_9$, $f_{14}$, $f_{18}$, $f_{24}$, $f_{32}$) in the lower frequency region are orbital harmonics, and three high frequencies ($f_{19}$, $f_{20}$, $f_{22}$) appear to be sidelobes split from the main frequency of $f_1$ = 22.77503 day$^{-1}$. Most of them are thought to be alias effects caused by the orbital frequency. For the 26 other frequencies, the pulsation periods and pulsation constants are in the ranges of 0.041$-$0.052 days and 0.013$-$0.016 days, respectively. These values and the position in the Hertzsprung-Russell diagram reveal that the primary component is a $\delta$ Sct pulsator. The observational properties of EPIC 245932119 are in good agreement with those for eclipsing binaries with $\delta$ Sct-type pulsating components.Comment: 17 pages, including 5 figures and 3 tables, accepted for publication in A

"Et problembarn?" : når politiet kommer på banen! : en teoretisk oppgave

Bachelor i politiutdannin

On a tropicalization of planar polynomial ODEs with finitely many structurally stable phase portraits

Recently, concepts from the emerging field of tropical geometry have been used to identify different scaling regimes in chemical reaction networks where dimension reduction may take place. In this paper, we try to formalize these ideas further in the context of planar polynomial ODEs. In particular, we develop a theory of a tropical dynamical system, based upon a differential inclusion, that has a set of discontinuities on a subset of the associated tropical curve. The development is inspired by an approach of Peter Szmolyan that uses the connection of tropical geometry with logarithmic paper. In this paper, we define a phaseportrait, a notion of equivalence and characterize structural stability. Furthermore, we demonstrate the results on several examples, including a(n) (generalized) autocatalator model. Our main result is that there are finitely many equivalence classes of structurally stable phase portraits and we enumerate these ($15$ in total) in the context of the generalized autocatalator model. We believe that the property of finitely many structurally stable phase portraits underlines the potential of the tropical approach, also in higher dimension, as a method to obtain and identify skeleton models in chemical reaction networks in extreme parameter regimes

Theory and applications of supercycled symmetry-based recoupling sequences in solid-state NMR

We present the theoretical principles of supercycled symmetry-based recoupling sequences in solid-state magic-angle-spinning NMR. We discuss the construction procedure of the SR26 pulse sequence, which is a particularly robust sequence for double-quantum homonuclear dipole-dipole recoupling. The supercycle removes destructive higher-order average Hamiltonian terms and renders the sequence robust over long time intervals. We demonstrate applications of the SR26 sequence to double-quantum spectroscopy, homonuclear spin counting, and determination of the relative orientations of chemical shift anisotropy tensors

Burnout and Its Antecedents:Considering Both Work and Household Time Claims, and Flexibility in Relation to Burnout

This study contributes to the previous literature by examining how flexible work arrangements interact with work and family time claims to affect burnout. It does so by providing a theoretical framework and empirical test of the interaction of flexibility with the effect of work and family time claims on burnout. Hypotheses and predictions based on previous literature are tested by Ordinary Least Squared regression models using data from the Time Competition Survey, constituting a sample of 1,058 employees of 89 function groups within 30 organizations. We found no main effects of work and family time claims or flexible work arrangements on burnout. However, the results do show an interaction of flexible working hours with the effect of work and family time claims on burnout. Specifically, the higher an individual's work and family time claims, the more this person benefits from having flexible working hours. In general, the results support the proposition that the relationship between work and family time claims and burnout differs for individuals with different levels of flexible work arrangements.</p

Thermal and electrical modelling of polymer cored BGA interconnects

Polymer cored BGA/CSP balls have been proposed as a more reliable alternative to solid solder balls for demanding application environments. Their potential advantages are dependant on their increased compliance compared with a solid solder ball, thereby reducing the level of stress imposed on the solder joints during exposure to cyclic thermal loads and impacts. The latter is of particular importance for hand held products assembled using lead free solders, which are much more brittle than traditional tin-lead alloys, but this may also be important for harsh environment applications where tinlead solders are still being used, such as in aerospace and defence electronics applications. The increased compliance of a polymer cored ball may reduce the requirement for underfilling of components in hand held products, and allow adoption of BGA/CSP for safety critical applications in harsh environments. Such polymer cored interconnects are however likely to provide a reduced thermal and electrical conductivity and it is important to ensure any such effects do not impact upon the thermal and electrical performance of the product. This paper utilises analytical and computational modelling techniques to achieve an understanding of the effect of conductor particle geometry and properties on thermal and electrical performance. Such models offer a route to appropriate materials selection for the polymer spheres and their conductive coatings, and for establishing optimum design parameters such as ball diameter, conductive coating thickness, solder pad diameter, and solder volumes. The results confirm that the introduction of polymer cored BGA balls will result in some increases in thermal and electrical resistance, but that these changes will have minor impacts on the overall performance of products