Testing stability in a spatial unilateral autoregressive model

ABSTRACT

Least squares estimator of the stability parameter ? ? |α| + |β| for a spatial unilateral autoregressive process X_{k, ?} = αX_{k ? 1, ?} + βX_{k, ? ? 1} + ?_{k, ?} is investigated and asymptotic normality with a scaling factor n^5/4 is shown in the unstable case ? = 1. The result is in contrast to the unit root case of the AR(p) model X_k = α₁X_{k ? 1} + ??? + α_pX_{k ? p} + ?_k, where the limiting distribution of the least squares estimator of the unit root parameter ? ? α₁ + ??? + α_p is not normal.     

Branded Solidarity in Fair Trade Communication on Facebook

The objective of fair trade to achieve economic justice through markets depends on establishing, via moral education, bonds of solidarity between Northern consumers and impoverished Southern producers. Moral education is increasingly realised by commercial brands who take advantage of the opportunities offered by social media. This article analyses the discursive construction of solidarity in the brand communication of Pukka (UK) and Pizca del Mundo (Poland) on Facebook. It identifies 3 discourses of solidarity: ‘solidarity through legitimation’, which presents the rationale for solidarity with Southern producers; ‘solidarity through affinity’, which constructs a moral economy between Southern producers and Northern consumers; and ‘solidarity through lifestyle’, which proposes everyday actions that can be undertaken by consumers to support Southern producers. These discourses are employed by the brands to different extents, with Pizca del Mundo attempting to establish a fair trade market in Poland and Pukka with an aim to increase sales of their fair trade products. The article concludes that primarily the discourses of ‘solidarity through legitimation’ and ‘solidarity through affinity’ serve moral education whose objective is to generate sustained commitment towards Southern producers as distant others.     

Estimating the Risk of a Down's Syndrome Term Pregnancy Using Age and Serum Markers: Comparison of Various Methods

The risk of an individual woman having a pregnancy associated with Down's syndrome is estimated given her age, α-fetoprotein, human chorionic gonadotropin, and pregnancy-specific β1-glycoprotein levels. The classical estimation method is based on discriminant analysis under the assumption of lognormality of the marker values, but logistic regression is also applied for data classification. In the present work, we compare the performance of the two methods using a dataset containing the data of almost 89,000 unaffected and 333 affected pregnancies. Assuming lognormality of the marker values, we also calculate the theoretical detection and false positive rates for both the methods.     

Intonation,identity and contact‐induced change among Polish‐speaking migrants in the U.K.

This article examines intonational variation in a language contact situation. The study contributes to sociolinguistic research on the social meaning of intonational variation (Podesva 2006 ; Levon 2014 ). Intonation is studied in a multilingual context of global mobility: within a group of Polish‐speaking migrants in Britain who, thanks to cheap transportation and new channels of communication, could make use of linguistic resources unlimited by territorial boundaries from the beginning of their transnational experience. The study shows that speakers with seemingly similar linguistic and cultural profiles make use of intonation patterns in different ways in the context of the narrative of the self: speakers oriented towards the global economy and the English‐speaking world incorporate a mainly English intonational pattern, the fall‐rise, with increased frequency to do interactional work that it does in English, while other groups maintain Standard Polish norms. As shown, intonational variation participates in the creation of fluid identities that blur linguistic and sociocultural boundaries.