Some results on the structure and spectra of matrix-products

We consider certain matrix-products where successive matrices in the product belong alternately to a particular qualitative class or its transpose. The main theorems relate structural and spectral properties of these matrix-products to the structure of underlying bipartite graphs. One consequence is a characterisation of caterpillars: a graph is a caterpillar if and only if all matrix-products associated with it have real nonnegative spectrum. Several other equivalences of this kind are proved. The work is inspired by certain questions in dynamical systems where such products arise naturally as Jacobian matrices, and the results have implications for the existence and stability of equilibria in these systems

Reexamining the Impact of Employee Relocation Assistance on Housing Prices

In this paper, we reexamine the issue of whether corporate relocation assistance programs for transferred employees significantly affect sale prices of single-family homes. We estimate a hedonic price equation that includes physical housing characteristics, location factors, occupancy status, and type of seller for a sample of 2,441 transactions. Seller types include (a) transferred employees who were given direct relocation assistance, (b) transferred employees who were not given direct relocation assistance, and (c) sellers who were not facing an employment transfer. After controlling for vacancy and tenant occupancy, we find that houses sold by transferred employees who receive direct relocation assistance exhibit no significant price differential, but that houses sold by transferred employees who do not receive direct relocation assistance sell at a discount of approximately 3%.

Assembly flow simulation of a radar

A discrete event simulation model has been developed to predict the assembly flow time of a new radar product. The simulation was the key tool employed to identify flow constraints. The radar, production facility, and equipment complement were designed, arranged, and selected to provide the most manufacturable assembly possible. A goal was to reduce the assembly and testing cycle time from twenty-six weeks. A computer software simulation package (SLAM 2) was utilized as the foundation for simulating the assembly flow time. FORTRAN subroutines were incorporated into the software to deal with unique flow circumstances that were not accommodated by the software. Detailed information relating to the assembly operations was provided by a team selected from the engineering, manufacturing management, inspection, and production assembly staff. The simulation verified that it would be possible to achieve the cycle time goal of six weeks. Equipment and manpower constraints were identified during the simulation process and adjusted as required to achieve the flow with a given monthly production requirement. The simulation is being maintained as a planning tool to be used to identify constraints in the event that monthly output is increased. 'What-if' studies have been conducted to identify the cost of reducing constraints caused by increases in output requirement

The Land and the brand

The Agribusiness and Economics Research Unit at Lincoln University was commissioned to prepare this report assessing the contributions that the agri‐food sector has made to the wellbeing of New Zealanders over the decades and in the present day. The purpose of this research is to indicate how industry‐led initiatives and private‐public partnerships might build on the sector’s historical successes for ongoing economic prosperity into the future. The agri‐food sector continues to dominate the country’s merchandise exports. The dairy sector in 2013/14 generated export revenue of just over $18 billion, followed by meat and wool (more than$8 billion), forestry (more than $5.1 billion), horticulture (nearly$3.8 billion) and seafood (more than $1.7 billion)

Beijing beef consumer consumption behaviours and product preferences: A Latent Class Analysis of New Zealand beef tenderloin

This study is part of a research programme entitled Unlocking Export Prosperity from the Agri-food Values of Aotearoa New Zealand. It is funded by the Ministry of Business, Innovation and Employment (MBIE) Endeavour Fund for science research programmes. The research aims to provide new knowledge on how local enterprises can achieve higher returns by ensuring global consumers understand the distinctive qualities of the physical, credence and cultural attributes of agri-food products that are “Made in New Zealand”. Agricultural exports are an important contributor to the New Zealand (NZ) economy. While NZ historically relied on key markets such as the United Kingdom for export trade, NZ has more recently significantly expanded its export markets and China has become established as an important beef product destination. It is critically important for NZ exporters to understand export markets and the different cultures and preferences of those consumers to safeguard market access, and for realising potential premiums. This report describes the application of a survey of Beijing beef tenderloin consumers that is designed to examine consumption behaviour and consumer willingness-to-Pay (WTP) for credence attributes. While search attributes such as price or colour can be observed directly, and experience attributes such as flavour can be assessed when consumed, credence attributes such as environmental sustainability cannot be immediately seen or experienced at the point of sale. For products promoting credence attributes, the role of verification, including labelling, is of significant importance. Our approach is to apply a Discrete Choice Experiment economic valuation method, analysed using a statistical approach called Latent Class Modelling that describes profiles for different consumer segments identified in the data and provides estimates of attribute WTP across these segments

Japanese kiwifruit consumer consumption behaviours and product preferences: A Latent Class Analysis of New Zealand kiwifruit

This study is part of a research programme entitled Unlocking Export Prosperity from the Agri-food Values of Aotearoa New Zealand. It is funded by the Ministry of Business, Innovation and Employment (MBIE) Endeavour Fund for science research programmes. Information on this research programme including reports of other surveys is available from the AERU website https://www.aeru.co.nz/projects/uep. The research aims to provide new knowledge on how local enterprises can achieve higher returns by ensuring global consumers understand the distinctive qualities of the physical, credence and cultural attributes of agri-food products that are “Made in New Zealand”. Agricultural exports are an important contributor to the New Zealand (NZ) economy. While NZ historically relied on key markets such as the United Kingdom for export trade, NZ has more recently significantly expanded its export markets and Japan has become established as an important kiwifruit destination. It is critically important for NZ exporters to understand export markets and the different cultures and preferences of those consumers to safeguard market access, and for realising potential premiums. This report describes the application of a survey of Japanese kiwifruit consumers that is designed to examine consumption behaviour and consumer Willingness-to-Pay (WTP) for credence attributes. While search attributes such as price or colour can be observed directly, and experience attributes such as flavour or texture can be assessed when consumed, credence attributes such as environmental sustainability cannot be immediately seen or experienced at the point of sale. For products promoting credence attributes, the role of verification including labelling is of significant importance. Our approach is to apply a Discrete Choice Experiment economic valuation method, analysed using a statistical approach called Latent Class Modelling that describes profiles for different consumer segments identified in the data and provides estimates of attribute WTP across these segments

Sampling a Littoral Fish Assemblage: Comparison of Small-Mesh Fyke Netting and Boat Electrofishing

We compared small-mesh (4-mm) fyke netting and boat electrofishing for sampling a littoral fish assemblage in Muskegon Lake, Michigan. We hypothesized that fyke netting selects for small-bodied fishes and electrofishing selects for large-bodied fishes. Three sites were sampled during May (2004 and 2005), July (2005 only), and September (2004 and 2005). We found that the species composition of captured fish differed considerably between fyke netting and electrofishing based on nonmetric multidimensional scaling (NMDS). Species strongly associated with fyke netting (based on NMDS and relative abundance) included the brook silverside Labidesthes sicculus, banded killifish Fundulus diaphanus, round goby Neogobius melanostomus, mimic shiner Notropis volucellus, and bluntnose minnow Pimephales notatus, whereas species associated with electrofishing included the Chinook salmon Oncorhynchus tshawytscha, catostomids (Moxostoma spp. and Catostomus spp.), freshwater drum Aplodinotus grunniens, walleye Sander vitreus, gizzard shad Dorosoma cepedianum, and common carp Cyprinus carpio. The total length of fish captured by electrofishing was 12.8 cm (95% confidence interval ¼ 5.5– 17.2 cm) greater than that of fish captured by fyke netting. Size selectivity of the gears contributed to differences in species composition of the fish captured, supporting our initial hypothesis. Thus, small-mesh fyke nets and boat electrofishers provided complementary information on a littoral fish assemblage. Our results support use of multiple gear types in monitoring and research surveys of fish assemblages. Copyright by the American Fisheries Society 2007, Originally published in the North American Journal of Fisheries Management 27: 825-831, 2007

Facial recognition during early motherhood: Investigating the persistence of age and affect biases

Converging evidence demonstrates increased levels of sensitivity to infant faces in mothers. This may be reflective of a series of psychological and neurobiological changes that occur in the transition to, and during early, parenthood for the purpose of appropriate caregiving; however, this enhanced infant facial recognition is in contrast with the general adult literature regarding facial processing. In the current study, we aimed to replicate a prior study of emotion facial recognition in pregnant women in a sample of mothers with children under a year old, utilizing a paradigm in which adult and infant faces gradually changed from neutral expressions to either happy or sad expressions. Mothers were faster at the recognition of adult faces in comparison to infant faces, and were also faster at happy faces in comparison to sad faces. Results are discussed in context of the current processing literature regarding the perinatal period, and implications for the persistence of the own-age bias and happy face advantage are considered

Modularity and Intrinsic Evolvability of Hsp90-Buffered Change

Hsp90 controls dramatic phenotypic transitions in a wide array of morphological features of many organisms. The genetic-background dependence of specific abnormalities and their response to laboratory selection suggested Hsp90 could be an ‘evolutionary capacitor’, allowing developmental variation to accumulate as neutral alleles under normal conditions and manifest selectable morphological differences during environmental stress. The relevance of Hsp90-buffered variation for evolution has been most often challenged by the idea that large morphological changes controlled by Hsp90 are unconditionally deleterious. To address this issue, we tested an Hsp90-buffered abnormality in Drosophila for unselected pleiotropic effects and correlated fitness costs. Up to 120-fold differences in penetrance among six highly related selection lines, started from an initially small number of flies and rapidly selected for and against a deformed eye trait (dfe), did not translate into measurable differences in any of several tests of viability, lifespan or competitive fitness. Nor were 17 dfe Quantitative Trait Loci (QTL) associated with fitness effects in over 1,400 recombinant lines. Our ability to detect measurable effects of inbreeding, media environment and the white mutation in the selection line backgrounds independent of dfe penetrance suggests that, within the limitations of laboratory tests of fitness, this large morphological change controlled by Hsp90 was selectable independent of strong, correlated and unconditionally deleterious effects—abundant, polygenic variation hidden by Hsp90 allows potentially deleterious alleles to be readily replaced during selection by less deleterious alleles with similar phenotypic effects. Hsp90 links environmental stress with the expression of developmental variation controlling unprecedented morphological plasticity. As outlined here and in the companion paper of this issue, the complex genetic architecture of Hsp90-buffered variation supports a remarkable modularity of Hsp90 effects on quantitative and qualitative phenotypes, consistent with the ‘Hsp90 capacitor hypothesis’ and standard quantitative genetic models of threshold traits