Branching rate expansion around annihilating random walks

We present some exact results for branching and annihilating random walks. We compute the nonuniversal threshold value of the annihilation rate for having a phase transition in the simplest reaction-diffusion system belonging to the directed percolation universality class. Also, we show that the accepted scenario for the appearance of a phase transition in the parity conserving universality class must be improved. In order to obtain these results we perform an expansion in the branching rate around pure annihilation, a theory without branching. This expansion is possible because we manage to solve pure annihilation exactly in any dimension.Comment: 5 pages, 5 figure

A Free-Form Lensing Grid Solution for A1689 with New Mutiple Images

Hubble Space Telescope imaging of the galaxy cluster Abell 1689 has revealed an exceptional number of strongly lensed multiply-imaged galaxies, including high-redshift candidates. Previous studies have used this data to obtain the most detailed dark matter reconstructions of any galaxy cluster to date, resolving substructures ~25 kpc across. We examine Abell 1689 (hereafter, A1689) non-parametrically, combining strongly lensed images and weak distortions from wider field Subaru imaging, and we incorporate member galaxies to improve the lens solution. Strongly lensed galaxies are often locally affected by member galaxies, however, these perturbations cannot be recovered in grid based reconstructions because the lensing information is too sparse to resolve member galaxies. By adding luminosity-scaled member galaxy deflections to our smooth grid we can derive meaningful solutions with sufficient accuracy to permit the identification of our own strongly lensed images, so our model becomes self consistent. We identify 11 new multiply lensed system candidates and clarify previously ambiguous cases, in the deepest optical and NIR data to date from Hubble and Subaru. Our improved spatial resolution brings up new features not seen when the weak and strong lensing effects are used separately, including clumps and filamentary dark matter around the main halo. Our treatment means we can obtain an objective mass ratio between the cluster and galaxy components, for examining the extent of tidal stripping of the luminous member galaxies. We find a typical mass-to-light ratios of M/L_B = 21 inside the r<1 arcminute region that drops to M/L_B = 17 inside the r<40 arcsecond region. Our model independence means we can objectively evaluate the competitiveness of stacking cluster lenses for defining the geometric lensing-distance-redshift relation in a model independent way.Comment: 23 pages with 25 figures Replced with MNRAS submitted version. Some figures have been corrected and minor text edit

Participatory Approach to Optimizing Cabbage Fertilization System for Improved Yield, Quality and Shelf Life

Cabbage fertilization system was optimized following the participatory approach by factoring in farmers’ practices, conducting optimization trials on farmers’ field, and employing farmer-researcher co-management of on-farm trials. Five different rates of fertilizer application were documented in the survey of farmers in a vegetable-growing area in Central Philippines. They served as basis for the fertilizer treatments (2 organic fertilizer levels using chicken dung or CD and 5 inorganic fertilizer levels using complete fertilizer 14-14-14 and urea 46-0-0) tested in on-farm trials in the dry season (December to May) and wet season (June to November). Other cultural practices were those employed by farmers with some good practices introduced. Optimum fertilization rate was 2.3 tons CD/ha + 112-47-47 (336 kg 14-14-14 and 141 kg 46-0-0 per hectare) for both dry and wet season crops, giving yields of 29.5 and 10.7 tons/ha, respectively, with net profit-cost ratio of 4.41 and 2.14, respectively, or more than 2-3 times higher than that of unfertilized crops. In addition, the heads produced were flatter and more compact and had longer shelf life due to lower weight loss and trimming loss, particularly for dry-season crop, compared to other fertilizer treatments. The participatory approach equipped farmers with first-hand knowledge and skills on how to improve existing cultural practices to generate high quality yields and farm profits

Fingerprinting the magnetic behavior of antiferromagnetic nanostructures using remanent magnetization curves

Antiferromagnetic (AF) nanostructures from Co3O4, CoO and Cr2O3 were prepared by the nanocasting method and were characterized magnetometrically. The field and temperature dependent magnetization data suggests that the nanostructures consist of a core-shell structure. The core behaves as a regular antiferromagnet and the shell as a two-dimensional diluted antiferromagnet in a field (2d DAFF) as previously shown on Co3O4 nanowires [Benitez et al., Phys. Rev. Lett. 101, 097206 (2008)]. Here we present a more general picture on three different material systems, i.e. Co3O4, CoO and Cr2O3. In particular we consider the thermoremanent (TRM) and the isothermoremanent (IRM) magnetization curves as "fingerprints" in order to identify the irreversible magnetization contribution originating from the shells. The TRM/IRM fingerprints are compared to those of superparamagnetic systems, superspin glasses and 3d DAFFs. We demonstrate that TRM/IRM vs. H plots are generally useful fingerprints to identify irreversible magnetization contributions encountered in particular in nanomagnets.Comment: submitted to PR

A Monolithic Time Stretcher for Precision Time Recording

Identifying light mesons which contain only up/down quarks (pions) from those containing a strange quark (kaons) over the typical meter length scales of a particle physics detector requires instrumentation capable of measuring flight times with a resolution on the order of 20ps. In the last few years a large number of inexpensive, multi-channel Time-to-Digital Converter (TDC) chips have become available. These devices typically have timing resolution performance in the hundreds of ps regime. A technique is presented that is a monolithic version of ``time stretcher'' solution adopted for the Belle Time-Of-Flight system to address this gap between resolution need and intrinsic multi-hit TDC performance.Comment: 9 pages, 15 figures, minor corrections made, to appear as JINST_008

Assessing the reliability of species distribution projections in climate change research

Aim: Forecasting changes in species distribution under future scenarios is one of the most prolific areas of application for species distribution models (SDMs). However, no consensus yet exists on the reliability of such models for drawing conclusions on species’ distribution response to changing climate. In this study, we provide an overview of common modelling practices in the field and assess the reliability of model predictions using a virtual species approach. Location: Global. Methods: We first review papers published between 2015 and 2019. Then, we use a virtual species approach and three commonly applied SDM algorithms (GLM, MaxEnt and random forest) to assess the estimated and actual predictive performance of models parameterized with different modelling settings and violations of modelling assumptions. Results: Most SDM papers relied on single models (65%) and small samples (N&nbsp;&lt;&nbsp;50, 62%), used presence-only data (85%), binarized models' output (74%) and used a split-sample validation (94%). Our simulation reveals that the split-sample validation tends to be over-optimistic compared to the real performance, whereas spatial block validation provides a more honest estimate, except when datasets are environmentally biased. The binarization of predicted probabilities of presence reduces models’ predictive ability considerably. Sample size is one of the main predictors of the real model accuracy, but has little influence on estimated accuracy. Finally, the inclusion of ecologically irrelevant predictors and the violation of modelling assumptions increases estimated accuracy but decreases real accuracy of model projections, leading to biased estimates of range contraction and expansion. Main conclusions: Our ability to predict future species distribution is low on average, particularly when models’ predictions are binarized. A robust validation by spatially independent samples is required, but does not rule out inflation of model accuracy by assumption violation. Our findings call for caution in the application and interpretation of SDM projections under different climates

General framework of the non-perturbative renormalization group for non-equilibrium steady states

This paper is devoted to presenting in detail the non-perturbative renormalization group (NPRG) formalism to investigate out-of-equilibrium systems and critical dynamics in statistical physics. The general NPRG framework for studying non-equilibrium steady states in stochastic models is expounded and fundamental technicalities are stressed, mainly regarding the role of causality and of Ito's discretization. We analyze the consequences of Ito's prescription in the NPRG framework and eventually provide an adequate regularization to encode them automatically. Besides, we show how to build a supersymmetric NPRG formalism with emphasis on time-reversal symmetric problems, whose supersymmetric structure allows for a particularly simple implementation of NPRG in which causality issues are transparent. We illustrate the two approaches on the example of Model A within the derivative expansion approximation at order two, and check that they yield identical results.Comment: 28 pages, 1 figure, minor corrections prior to publicatio