Allowing for intra-respondent variations in coefficients estimated on repeated choice data

Partly as a result of the increasing reliance on Stated Choice (SC) data, the vast majority of discrete choice modelling applications are now estimated on data containing multiple observations for each respondent. At the same time there has been growing interest in the representation of unexplained heterogeneity in choice data, using random coefficients models such as Mixed Multinomial Logit (MMNL). The presence of multiple observations for each respondent can indeed be a great asset in the identification of such variations in tastes. However, in this paper, we question the validity of the common assumption that tastes vary across respondents but stay constant across repeated choices for the same respondent. We extend the existing framework for the MMNL analysis of panel data by allowing for intra-respondent heterogeneity on top of inter-respondent heterogeneity. An empirical analysis making use of a SC dataset for route choice confirms our hypotheses and shows that superior performance is obtained by our more general model

LET-99 functions in the astral furrowing pathway, where it is required for myosin enrichment in the contractile ring.

The anaphase spindle determines the position of the cytokinesis furrow, such that the contractile ring assembles in an equatorial zone between the two spindle poles. Contractile ring formation is mediated by RhoA activation at the equator by the centralspindlin complex and midzone microtubules. Astral microtubules also inhibit RhoA accumulation at the poles. In the Caenorhabditis elegans one-cell embryo, the astral microtubule-dependent pathway requires anillin, NOP-1, and LET-99. LET-99 is well characterized for generating the asymmetric cortical localization of the Gα-dependent force-generating complex that positions the spindle during asymmetric division. However, whether the role of LET-99 in cytokinesis is specific to asymmetric division and whether it acts through Gα to promote furrowing are unclear. Here we show that LET-99 contributes to furrowing in both asymmetrically and symmetrically dividing cells, independent of its function in spindle positioning and Gα regulation. LET-99 acts in a pathway parallel to anillin and is required for myosin enrichment into the contractile ring. These and other results suggest a positive feedback model in which LET-99 localizes to the presumptive cleavage furrow in response to the spindle and myosin. Once positioned there, LET-99 enhances myosin accumulation to promote furrowing in both symmetrically and asymmetrically dividing cells

Selling Ice in Alaska: Employment Preferences and Statutory Exemptions for Alaska Native Corporations 40 Years After ANCSA

In 1971, Congress enacted the Alaska Native Claims Settlement Act (ANCSA) in order to settle land disputes between Alaska Natives and the federal government. ANCSA established Alaska Native Corporations (ANCs), which were tasked with managing settlement funds to provide for the health, education, and economic welfare of Alaska Natives. To enable the ANCs to promote the interests of their shareholders, Congress exempted ANCs from certain employment restrictions contained in Title VII of the Civil Rights Act, but did not exempt ANCs from other worker-protective legislation. In subsequent decades, courts reviewing the preferential practices of ANCs have often construed these statutory exemptions narrowly, thus exposing ANCs to liability under various anti-discrimination statutes. This Article argues that Congress never intended to subject ANCs to these pieces of worker-protective legislation, despite court holdings to the contrary. The Article proposes two possible solutions to this discrepancy: (1) congressional amendment of ANCSA to clarify and further limit the extent of ANC liability; and (2) judicial adoption of a two-part test which would consider employment policies giving preference to Alaska Native shareholders in light of Congress\u27s intent to protect such preferences

Effectiveness of a Rigid Grate for Excluding Pacific Halibut, Hippoglossus stenolepis, From Groundfish Trawl Catches

A rigid grate was installed in a groundfish trawl to test its effectiveness in excluding Pacific halibut, Hippoglossus stenolepis, from commercial flatfish catches in the Gulf of Alaska. The grate was located ahead of the trawl codend to direct halibut toward an escape opening while allowing target species to pass through toward the codend. In an experimental fishery, the escape rate of halibut was estimated at 94%, while 72% of the Dover sole, Microstomas pacificus, 67% of the rex sole, Glyptocephalus zachirus, and 79% of the flathead sole, Hippoglossoides elassodon, were retained

Becoming a Child Care Provider

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Seasonal labour is the most profitable use of labour in broadacre crop dominant farms

Labour scarcity and affordability have encouraged many farmers in Western Australia to focus more on cropping than sheep production. Many farmers are opting to run low input livestock systems. This paper examines labour demand for sheep and cropping during the production year, combined with various scenarios of labour availability and cost. The implications for farm profitability and enterprise selection are examined using the bio-economic farming systems model MIDAS (Model of an Integrated Dryland Agricultural System). Labour requirements for sheep are far greater than those for cropping. Additionally the labour requirements for sheep are high in all production periods whilst the seasonal nature of cropping means more time is required only at certain times of the year, particularly at seeding and harvest. This means that the most profitable labour option is employing casual labour during periods of peak demand for cropping. The lesser relative profitability of the sheep enterprise makes employing a permanent worker the least profitable labour option. By contrast, employing casual labour during busy periods for cropping is more profitable but it is also associated with only small areas of perennial pastures being sown which has environmental implications. The logistics of employing labour at only certain times of the year compared to employing a full time worker means that farmers need to pay more per week to employ these workers or do the extra work themselves.agriculture, labour, farm modelling, cropping, sheep,