A metafrontier approach to measuring technical efficiencies across the UK dairy sector

A regional approach is applied to measure technical efficiencies on dairy farms which employs the deterministic metafrontier approach. We construct six super regions for the UK, i.e. Eastern, Western, Northern England, Wales, Scotland and Northern Ireland. Data are collected through three different administrative systems, all be it under the same FADN guidance. We find for dairy farming comparative indicators of performance in all three data sets. The stochastic frontier approach is applied to construct 6 regional frontiers and a pooled (UK) dataset for comparison. A likelihood ratio test rejects the null hypothesis that these regions operate under a common frontier which may indicate bias in previous attempts to measure dairying efficiency at the country level. Mean technical efficiencies are high for the period 2005 to 2008, though there is some indication that little technical progress has occurred since decoupling of CAP payments from production in all regions. The metafrontier presents estimates against a common technology and mean scores range from below 0.50 for the English regions and Northern Ireland, 0.52 for Wales and 0.56 for Scotland. This paper promotes the application of the deterministic metafrontier approach for similar sub-country studies.Stochastic Production Frontiers, Metafrontiers, UK Farm Account Data, Dairy farming., Agricultural and Food Policy, Q12, D24, C23, C51,

New hybrid quadrature schemes for weakly singular kernels applied to isogeometric boundary elements for 3D Stokes flow

This work proposes four novel hybrid quadrature schemes for the efficient and accurate evaluation of weakly singular boundary integrals (1/r kernel) on arbitrary smooth surfaces. Such integrals appear in boundary element analysis for several partial differential equations including the Stokes equation for viscous flow and the Helmholtz equation for acoustics. The proposed quadrature schemes apply a Duffy transform-based quadrature rule to surface elements containing the singularity and classical Gaussian quadrature to the remaining elements. Two of the four schemes additionally consider a special treatment for elements near to the singularity, where refined Gaussian quadrature and a new moment-fitting quadrature rule are used. The hybrid quadrature schemes are systematically studied on flat B-spline patches and on NURBS spheres considering two different sphere discretizations: An exact single-patch sphere with degenerate control points at the poles and an approximate discretization that consist of six patches with regular elements. The efficiency of the quadrature schemes is further demonstrated in boundary element analysis for Stokes flow, where steady problems with rotating and translating curved objects are investigated in convergence studies for both, mesh and quadrature refinement. Much higher convergence rates are observed for the proposed new schemes in comparison to classical schemes

Non-stationary Gaussian Process Surrogates

We provide a survey of non-stationary surrogate models which utilize Gaussian processes (GPs) or variations thereof, including non-stationary kernel adaptations, partition and local GPs, and spatial warpings through deep Gaussian processes. We also overview publicly available software implementations and conclude with a bake-off involving an 8-dimensional satellite drag computer experiment. Code for this example is provided in a public git repository.Comment: 13 pages, 5 figure

Stepwise Unfolding of a β Barrel Protein by the AAA+ ClpXP Protease

In the AAA+ ClpXP protease, ClpX uses the energy of ATP binding and hydrolysis to unfold proteins before translocating them into ClpP for degradation. For proteins with C-terminal ssrA tags, ClpXP pulls on the tag to initiate unfolding and subsequent degradation. Here, we demonstrate that an initial step in ClpXP unfolding of the 11-stranded β barrel of superfolder GFP-ssrA involves extraction of the C-terminal β strand. The resulting 10-stranded intermediate is populated at low ATP concentrations, which stall ClpXP unfolding, and at high ATP concentrations, which support robust degradation. To determine if stable unfolding intermediates cause low-ATP stalling, we designed and characterized circularly permuted GFP variants. Notably, stalling was observed for a variant that formed a stable 10-stranded intermediate but not for one in which this intermediate was unstable. A stepwise degradation model in which the rates of terminal-strand extraction, strand refolding or recapture, and unfolding of the 10-stranded intermediate all depend on the rate of ATP hydrolysis by ClpXP accounts for the observed changes in degradation kinetics over a broad range of ATP concentrations. Our results suggest that the presence or absence of unfolding intermediates will play important roles in determining whether forced enzymatic unfolding requires a minimum rate of ATP hydrolysis.National Institutes of Health (U.S.) (Grant AI-15706

A general isogeometric finite element formulation for rotation-free shells with embedded fibers and in-plane bending

This paper presents a general, nonlinear finite element formulation for rotation-free shells with embedded fibers that captures anisotropy in stretching, shearing, twisting and bending -- both in-plane and out-of-plane. These capabilities allow for the simulation of large sheets of heterogeneous and fibrous materials either with or without matrix, such as textiles, composites, and pantographic structures. The work is a computational extension of our earlier theoretical work (Duong et al., 2021) that extends existing Kirchhoff-Love shell theory to incorporate the in-plane bending resistance of initially straight or curved fibers. The formulation requires only displacement degrees-of-freedom to capture all mentioned modes of deformation. To this end, isogeometric shape functions are used in order to satisfy the required $C^1$-continuity for bending across element boundaries. The proposed formulation can admit a wide range of material models, such as surface hyperelasticity that does not require any explicit thickness integration. To deal with possible material instability due to fiber compression, a stabilization scheme is added. Several benchmark examples are used to demonstrate the robustness and accuracy of the proposed computational formulation.Comment: This version updates the paper format and adjust the units in figure axes, results unchange

Soybean Marketing Methods and Characteristics of Arkansas Grain Handlers

Arkansas producers should acquaint themselves with all marketing methods available to them. Of particular importance is the pervasiveness of price risk within the current economic climate. This bulletin provides insights into the current structure of the grain marketing industry, soybean handler characteristics, and the availability and use of marketing alternatives in Arkansas. Arkansas soybean handlers were surveyed in 1998 to determine the marketing practices of both handlers and producers for the 1996 crop year. Particular emphasis was placed on the types of contracting methods offered by these handlers. Both facility size and corporate structure were found to play a significant role in determining the types of marketing contracts offered as well as the frequency of usage by producers

Relation extraction with automatic ontonotes annotation and ETC

Intuitively, it seems as though natural language processing tasks might benefit from explicit representations of the syntactic and semantic properties of text. Ontonotes is a dataset which attempts to annotate texts, to represent as much as possible of the meaning of the text explicitly within the annotation. Many tools exist for automatic annotation of various semantic features of raw text. This project uses these tools to annotate text from DocRED(Document Level Relation Extraction Dataset) with Ontonotes-style structured data, which is then used to train ETC, an extended transformer architecture for working with structured data, on the task of document-level relation extraction. We evaluate the hypothesis that ETC will perform better on this semantically-annotated dataset than the base DocRED dataset.Keywords: NLP, Relation Extraction, Ontonotes, ETC, DocRE

An improved synthesis of (2E,4Z)-6-(benzyloxy)-4-bromohexa-2,4-dien-1-ol

An improved synthesis of (2E,4Z)-6-(benzyloxy)-4-bromohexa-2,4-dien-1-ol has been devised. This new route increases the throughput and yield of the diene product by circumventing a low yielding preparation of boronic acid intermediate as well as removing the need to use multi-gram quantities of highly toxic thallium salts. In the process of developing this new route, a higher yielding preparation of ( E)-3-hydroxyprop-1-enylboronic acid was also achieved. (c) 2007 Elsevier Ltd. All rights reserved