Executing matrix multiply on a process oriented data flow machine

The Process-Oriented Dataflow System (PODS) is an execution model that combines the von Neumann and dataflow models of computation to gain the benefits of each. Central to PODS is the concept of array distribution and its effects on partitioning and mapping of processes.In PODS arrays are partitioned by simply assigning consecutive elements to each processing element (PE) equally. Since PODS uses single assignment, there will be only one producer of each element. This producing PE owns that element and will perform the necessary computations to assign it. Using this approach the filling loop is distributed across the PEs. This simple partitioning and mapping scheme provides excellent results for executing scientific code on MIMD machines. In this way PODS allows MIMD machines to exploit vector and data parallelism easily while still providing the flexibility of MIMD over SIMD for multi-user systems.In this paper, the classic matrix multiply algorithm, with 1024 data points, is executed on a PODS simulator and the results are presented and discussed. Matrix multiply is a good example because it has several interesting properties: there are multiple code-blocks; a new array must be dynamically allocated and distributed; there is a loop-carried dependency in the innermost loop; the two input arrays have different access patterns; and the sizes of the input arrays are not known at compile time. Matrix multiply also forms the basis for many important scientific algorithms such as: LU decomposition, convolution, and the Fast-Fourier Transform.The results show that PODS is comparable to both Iannucci's Hybrid Architecture and MIT's TTDA in terms of overhead and instruction power. They also show that PODS easily distributes the work load evenly across the PEs. The key result is that PODS can scale matrix multiply in a near linear fashion until there is little or no work to be performed for each PE. Then overhead and message passing become a major component of the execution time. With larger problems (e.g., >/=16k data points) this limit would be reached at around 256 PEs

Winter Canola Variety Trial

In 2012, the University of Vermont Extension Northwest Crops and Soils Program initiated a winter canola variety trial in Alburgh, VT as part of the 2011-2012 National Winter Canola Variety Trial. In the past few years, many farms in the Northeast have been engaged in on-farm fuel production; farmers must be able to reliably produce a high-yielding crop in order for this to be economically feasible. Growing winter canola holds many possible advantages for Vermont farms since it is sown in the early fall, allowing it to easily fit into rotations following short-season grain or corn. Winter canola is a relatively new crop for the Northeast, and varietal selection is one of the most important aspects of production since it significantly influences seed and oil yield potential. The goal of this trial was to evaluate varieties that can survive the harsh winters of our region and ultimately produce high yields

Using citizen science to monitor pollination services

1. Pollination by insects is a vital ecosystem service and the need for its assessment is increasing in recognition and political pressure, but there are currently no large-scale systematic monitoring schemes in place to measure the direct provision of this service. 2. This study tested a protocol for using a citizen science approach to quantify pollination service provision in gardens and allotments, requiring participants to grow Vica faba L. plants and carry out some simple manipulations of the pollination environment (flowers with bees excluded, flowers hand-pollinated, or flowers left for local pollinators to visit). Volunteers assessed yield in the three treatments. 3. Eighty participants from across the U.K. successfully completed all parts of the protocol; a further 93 participants were unsuccessful but actively engaged with the project. 4. Overall, the present results suggest that pollination services for V. faba are currently not limiting in gardens or allotments in the U.K. It is possible and cost-effective to recruit volunteers to collect data on pollination deficits using this protocol. 5. The approach used in this paper, which could readily be extended to incorporate other plant species reliant on different guilds of pollinators, is feasible for adoption as a national monitoring scheme for pollination services. Key words. Bees, bumblebees, crop yield, ecosystem services, pollinator, urban, Viciafab

Effect of Acacia tortilis pods on intake, digestibility and nutritive quality of goat diets in southwestern Eritrea

Fresh Acacia tortilis pods were mixed with low quality native grass hay to form the following five rations: 100% hay (T 1), 25% pods and 75% hay (T 2), 50% pods and 50% hay (T 3), 75% pods and 25% hay (T 4) and 100% pods (T 5) on ‘as fed’weight basis. Fifteen male Barka goats, approximately one year old and 10–15kg body weight, were randomly assigned to the five rations and fed in individual pens. Chemical composition, dry matter intake (DMI), in vitro dry and organic matter digestibility and body weight changes of the animals were evaluated. The average crude protein content of the pods was about 47% higher than the 7% minimum required for normal rumen function, while that of the hay was about 13% below. Percent ash, neutral detergent fibre (NDF), acid detergent fibre (ADF), hemi-cellulose (HC), cellulose (CL) and acid detergent lignin (ADL) contents were higher in the hay than in the pods. The pods were, however, generally higher in Ca, P, Mg and Na than the hay. Average DMI (g d -1 and g kg-1 LBW), percent in vitro dry and organic matter digestibility and body weight gains (total kg and gd -1) increased with an increase in A. tortilis pods, up to 75% level and then begun to decline. However, despite the decrease, T 5 still had significantly (P< 0.05) higher feed digestibility and body weight gains than T 2 and T3. Thus, supplementing low quality range herbage with Acacia pods can considerably improve the nutritive value of range livestock diets, particularly during the dry season when other types of fodder are of extremely low quality

Evaluation of oilseed rape seed yield losses caused by Leptosphaeria biglobosa in central China

This document is the Accepted Manuscript version of the following article: Xiang Cai, Yongju Huang, Daohong Jiang, Bruce D. L. Fitt, Guoqing Li, and Long Yang, "Evaluation of oilseed rape seed yield losses caused by Leptosphaeria biglobosa in central China", European Journal of Plant Pathology, first published 9 June 2017. Under embargo. Embargo end date: 9 June 2018. The final publication is available at Springer via: http://dx.doi.org/10.1007/s10658-017-1266-x.Phoma stem canker of oilseed rape (Brassica napus), caused by Leptosphaeria maculans/L. biglobosa is a globally important disease. Severe phoma stem canker symptoms have been observed on winter oilseed rape in China but the seed yield loss caused by this disease remains unknown. In May 2012 and May 2013, 17 and 13 crops were surveyed, respectively, in seven counties of Hubei Province, central China. Stems with phoma stem canker disease symptoms were sampled for pathogen isolation and identification. Only L. biglobosa was identified by culture morphology and species-specific PCR; no L. maculans was found. To evaluate the yield losses, yield components (number of branches per plant, number of pods per plant, 1000-seed weight, number of seeds per pod) were assessed on healthy and diseased plants sampled from crops in four counties and on plants from inoculated pot experiments (plants of three cultivars were inoculated at the green bud stage by injecting L. biglobosa conidia into the stem between the first and second leaf scars). Results of the field surveys showed that diseased plants had 14–61% less branches and 32–83% less pods than healthy plants, respectively. The estimated seed yield loss varied from 10% to 21% and from 13% to 37% in 2012 and 2013, respectively. In the pot experiments, there were no differences in numbers of branches or pods but there were differences in number of seeds per pod between inoculated and control plants. For the three cultivars tested, the inoculated plants had yield losses of 29–56% compared with the control. This study indicates that L. biglobosa could cause substantial seed yield loss in China.Peer reviewedFinal Accepted Versio