On the Evolvability of Monotone Conjunctions with an Evolutionary Mutation Mechanism

A Bernoulli(p)n distribution Bn,p over {0, 1}n is a product distribution where each variable is satisfied with the same constant probability p. Diochnos (2016) showed that Valiant's swapping algorithm for monotone conjunctions converges efficiently under Bn,p distributions over {0, 1}n for any 0 < p < 1. We continue the study of monotone conjunctions in Valiant's framework of evolvability. In particular, we prove that given a Bn,p distribution characterized by some p ∈ (0, 1/3] ∪ {1/2}, then an evolutionary mechanism that relies on the basic mutation mechanism of a (1+1) evolutionary algorithm converges efficiently, with high probability, to an ε-optimal hypothesis. Furthermore, for 0 < α ≤ 3/13, a slight modification of the algorithm, with a uniform setup this time, evolves with high probability an ε-optimal hypothesis, for every Bn,p distribution such that p ∈ [α, 1/3 - 4α/9] ∪ {1/3} ∪ {1/2}.

The MOSDEF survey: an improved Voronoi binning technique on spatially resolved stellar populations at z ∼ 2

ABSTRACT We use a sample of 350 star-forming galaxies at 1.25 &lt; z &lt; 2.66 from the Multi-Object Spectrograph For Infra-Red Exploration (MOSFIRE) Deep Evolution Field survey to demonstrate an improved Voronoi binning technique that we use to study the properties of resolved stellar populations in z ∼ 2 galaxies. Stellar population and dust maps are constructed from the high-resolution CANDELS/3D-HST multiband imaging. Rather than constructing the layout of resolved elements (i.e. Voronoi bins) from the signal-to-noise (S/N) distribution of the H160-band alone, we introduce a modified Voronoi binning method that additionally incorporates the S/N distribution of several resolved filters. The spectral energy distribution (SED)-derived resolved E(B − V)stars, stellar population ages, star-formation rates (SFRs), and stellar masses that are inferred from the Voronoi bins constructed from multiple filters are generally consistent with the properties inferred from the integrated photometry within the uncertainties, with the exception of the inferred E(B − V)stars from our z ∼ 1.5 sample due to their UV slopes being unconstrained by the resolved photometry. The results from our multifilter Voronoi binning technique are compared to those derived from a ‘traditional’ single-filter Voronoi binning approach. We find that single-filter binning produces inferred E(B − V)stars that are systematically redder by 0.02 mag, on average, but could differ by up to 0.20 mag and could be attributed to poorly constrained resolved photometry covering the UV slope. Overall, we advocate that our methodology produces more reliable SED-derived parameters due to the best-fitting resolved SEDs being better constrained at all resolved wavelengths – particularly those covering the UV slope.

A functional–structural plant model that simulates whole- canopy gas exchange of grapevine plants (Vitis vinifera L.) under different training systems

Background and Aims Scaling from single-leaf to whole-canopy photosynthesis faces several complexities related to variations in light interception and leaf properties. To evaluate the impact of canopy strucuture on gas exchange, we developed a functional–structural plant model to upscale leaf processes to the whole canopy based on leaf N content. The model integrates different models that calculate intercepted radiation, leaf traits and gas exchange for each leaf in the canopy. Our main objectives were (1) to introduce the gas exchange model developed at the plant level by integrating the leaf-level responses related to canopy structure, (2) to test the model against an independent canopy gas exchange dataset recorded on different plant architectures, and (3) to quantify the impact of intra-canopy N distribution on crop photosynthesis. Methods The model combined a 3D reconstruction of grapevine (Vitis vinifera) canopy architecture, a light interception model, and a coupled photosynthesis and stomatal conductance model that considers light-driven variations in N distribution. A portable chamber device was constructed to measure whole-plant gas exchange to validate the model outputs with data collected on different training systems. Finally, a sensitivity analysis was performed to evaluate the impact on C assimilation of different N content distributions within the canopy. Key Results By considering a non-uniform leaf N distribution within the canopy, our model accurately reproduced the daily pattern of gas exchange of different canopy architectures. The gain in photosynthesis permitted by the non-uniform compared with a theoretical uniform N distribution was about 18 %, thereby contributing to the maximization of C assimilation. By contrast, considering a maximal N content for all leaves in the canopy overestimated net CO2 exchange by 28 % when compared with the non-uniform distribution. Conclusions The model reproduced the gas exchange of plants under different training systems with a low error (10 %). It appears to be a reliable tool to evaluate the impact of a grapevine training system on water use efficiency at the plant level.