Yield and photosynthetic rate of wheat under continuously high temperature

In tropical regions high temperature occurs throughout wheat growth cycle and is a major factor influencing growth and yield in this area. The aim of this work is to describe the responses to continuously-high temperatures on growth, photosynthesis and yield of wheat, under controlled conditions. Nias and Dewata (Indonesian wheat varieties) and Axe and Gladius (Australian varieties) were tested in growth room experiment with temperature and photoperiod chosen to simulate conditions on Lombok Island, at lowland (32/23°C) and highland (28/20°C) sites. The third temperature (25/15°C) was selected to represent temperature in a more temperate wheat-producing area. High temperature reduced yield and dry matter accumulation which was associated with a reduction in photosynthetic rate and stomata conductance and an increase in respiration rate. The reduction in photosynthetic rate at high temperature was not only due to lower stomatal conductance but also non-stomatal effects as mesophyll conductance and quantum yield were lower. Genetic variability in response to heat stress was evident with the Indonesian varieties being more tolerant to high temperatures than Australian varieties. Nias and Dewata produced higher yield and biomass and maintaining higher rates of photosynthesis. Maintaining high photosynthetic rate and high stomata conductance, are important characters in adapting wheat into tropical environment such as Lombok Island.A Zubaidi, D R Anugrahwati, G K McDonald and G Gil

Water use, water use efficiency, water soluble carbohydrate and yield of four varieties of wheat in continuously high temperatures

High temperatures are a common feature of the environment of tropical regions such as Lombok Island and although the effect can be alleviated by altitude, heat stress will be an important limitation to the productivity of wheat in this environment. The objectives of the experiment were to observe the responses of water use (WU), water use efficiency (WUE) and water soluble carbohydrate (WSC) to high temperatures on growth and yield of wheat under controlled conditions. In this experiment plants were grown under growth chambers at temperatures to simulate low and high elevation locations on Lombok Island. Water use, water use efficiency, WSC and yield of 4 wheat genotypes (2 Australian and 2 Indonesian varieties) grown at 3 temperatures (32°/23°C, 28°/20ºC, and 25°/15ºC day/night) were compared. Variation in water use, water use efficiency, and the concentration of water soluble carbohydrate was found. Indonesian wheat varieties, Nias and Dewata produced higher yield and biomass and maintaining higher rates of water use and remobilisation of water soluble carbohydrate from vegetative tissues to grain. The accumulation of water soluble carbohydrates was an important adaptive characteristic that was strongly associated with grain weight and grains per spikelet and maintained better yield.A Zubaidi, D R Anugrahwati, G Gill and G K McDonal

Feeding and Distribution of Porosity in Cast Al-Si Alloys as Function of Alloy Composition and Modification

Unmodified, Na-modified, and Sr-modified castings of Al-7 pct Si and Al-12.5 pct Si alloys were cast in molds in which it was possible to create different cooling conditions. It is shown how solidification influences the distribution of porosity at the surface and the center of the castings as a function of modification and Si content in sand- and chill-cast samples. Eutectic modification, Si content, and cooling conditions have a great impact on the distribution of porosity. Unmodified and Na-modified castings are more easily fed with porosity tending to congregate near the centerline of the casting, while Sr-modified castings solidify in a mushy manner that creates a more homogeneous distribution of porosity in the casting. The amount of porosity was highest in the Sr-modified alloys, lower in the Na-modified alloys, and lowest in the unmodified alloys. The size of the porosity-free layer and the effectiveness of the feeders were greater in the castings made with the steel chills due to the increased thermal gradients and consequent increase in the directionality of solidification

Constrained Supersymmetric Flipped SU(5) GUT Phenomenology

We explore the phenomenology of the minimal supersymmetric flipped SU(5) GUT model (CFSU(5)), whose soft supersymmetry-breaking (SSB) mass parameters are constrained to be universal at some input scale, $M_{in}$, above the GUT scale, $M_{GUT}$. We analyze the parameter space of CFSU(5) assuming that the lightest supersymmetric particle (LSP) provides the cosmological cold dark matter, paying careful attention to the matching of parameters at the GUT scale. We first display some specific examples of the evolutions of the SSB parameters that exhibit some generic features. Specifically, we note that the relationship between the masses of the lightest neutralino and the lighter stau is sensitive to $M_{in}$, as is the relationship between the neutralino mass and the masses of the heavier Higgs bosons. For these reasons, prominent features in generic $(m_{1/2}, m_0)$ planes such as coannihilation strips and rapid-annihilation funnels are also sensitive to $M_{in}$, as we illustrate for several cases with tan(beta)=10 and 55. However, these features do not necessarily disappear at large $M_{in}$, unlike the case in the minimal conventional SU(5) GUT. Our results are relatively insensitive to neutrino masses.Comment: 23 pages, 8 figures; (v2) added explanations and corrected typos, version to appear in EPJ

Non-crossing dependencies: Least effort, not grammar

The use of null hypotheses (in a statistical sense) is common in hard sciences but not in theoretical linguistics. Here the null hypothesis that the low frequency of syntactic dependency crossings is expected by an arbitrary ordering of words is rejected. It is shown that this would require star dependency structures, which are both unrealistic and too restrictive. The hypothesis of the limited resources of the human brain is revisited. Stronger null hypotheses taking into account actual dependency lengths for the likelihood of crossings are presented. Those hypotheses suggests that crossings are likely to reduce when dependencies are shortened. A hypothesis based on pressure to reduce dependency lengths is more parsimonious than a principle of minimization of crossings or a grammatical ban that is totally dissociated from the general and non-linguistic principle of economy.Postprint (author's final draft

Sensitivity projections for a dual-phase argon TPC optimized for light dark matter searches through the ionization channel

Dark matter lighter than 10  GeV/c2 encompasses a promising range of candidates. A conceptual design for a new detector, DarkSide-LowMass, is presented, based on the DarkSide-50 detector and progress toward DarkSide-20k, optimized for a low-threshold electron-counting measurement. Sensitivity to light dark matter is explored for various potential energy thresholds and background rates. These studies show that DarkSide-LowMass can achieve sensitivity to light dark matter down to the solar neutrino fog for GeV-scale masses and significant sensitivity down to 10  MeV/c2 considering the Migdal effect or interactions with electrons. Requirements for optimizing the detector’s sensitivity are explored, as are potential sensitivity gains from modeling and mitigating spurious electron backgrounds that may dominate the signal at the lowest energies