81 research outputs found
A within-attribute model of variety-seeking behavior
Existing models view variety seeking as the result of differences in the level of attribute satiation across attributes. An alternative within-attribute variety-seeking (WAVS) model is proposed. The model posits that variety seeking occurs among the nested features, or meaningful value ranges, of an underlying dimension. The resulting pattern of consumption is represented as an oscillation about a consumer's ideal point on the dimension. An empirical study that illustrates different oscillation patterns is reported.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47181/1/11002_2004_Article_BF00995114.pd
BioGPS: an extensible and customizable portal for querying and organizing gene annotation resources
BioGPS is a community based customisable gene annotation portal bringing together gene annotation resources on to a single platform
Distribution of misfolded prion protein seeding activity alone does not predict regions of neurodegeneration
Protein misfolding is common across many neurodegenerative diseases, with misfolded proteins acting as seeds for "prion-like" conversion of normally folded protein to abnormal conformations. A central hypothesis is that misfolded protein accumulation, spread and distribution is restricted to specific neuronal populations of the central nervous system and thus predict regions of neurodegeneration. We examined this hypothesis using a highly sensitive assay system for detection of misfolded protein seeds in a murine model of prion disease. Misfolded prion protein seeds were observed widespread throughout the brain accumulating in all brain regions examined irrespective of neurodegeneration. Importantly neither time of exposure nor amount of misfolded protein seeds present determined regions of neurodegeneration. We further demonstrate two distinct microglia responses in prion infected brains, a 11 novel homeostatic response in all regions and an innate immune response restricted to sites of 12 neurodegeneration. Therefore accumulation of misfolded prion protein alone does not define targeting 13 of neurodegeneration which instead results only when misfolded prion protein accompanies a specific 14 innate immune response
A large-scale study across the avian clade identifies ecological drivers of neophobia
Neophobia, or aversion to novelty, is important for adaptability and survival as it influences the ways in which animals navigate risk and interact with their environments. Across individuals, species and other taxonomic levels, neophobia is known to vary considerably, but our understanding of the wider ecological drivers of neophobia is hampered by a lack of comparative multispecies studies using standardized methods. Here, we utilized the ManyBirds Project, a Big Team Science large-scale collaborative open science framework, to pool efforts and resources of 129 collaborators at 77 institutions from 24 countries worldwide across six continents. We examined both difference scores (between novel object test and control conditions) and raw data of latency to touch familiar food in the presence (test) and absence (control) of a novel object among 1,439 subjects from 136 bird species across 25 taxonomic orders incorporating lab, field, and zoo sites. We first demonstrated that consistent differences in neophobia existed among individuals, among species, and among other taxonomic levels in our dataset, rejecting the null hypothesis that neophobia is highly plastic at all taxonomic levels with no evidence for evolutionary divergence. We then tested for effects of ecological factors on neophobia, including diet, sociality, habitat, and range, while accounting for phylogeny. We found that (i) species with more specialist diets were more neophobic than those with more generalist diets, providing support for the Neophobia Threshold Hypothesis; (ii) migratory species were also more neophobic than nonmigratory species, which supports the Dangerous Niche Hypothesis. Our study shows that the evolution of avian neophobia has been shaped by ecological drivers and demonstrates the potential of Big Team Science to advance our understanding of animal behavior
A Model of Balanced Choice Behavior
In some product categories, consumers appear to alternate among items in a consistent and purposeful, though not entirely deterministic, fashion. Such alternation occurs even in the absence of any apparent external influences on choice. To explain such balanced choice behavior, we present a model based upon the premise that past consumption influences the utility of items on subsequent choice occasions. Individuals may seek variety on certain product attributes and exhibit loyalty toward others. The model specification yields a logit choice model which may be calibrated using consumption diary panel data at the individual or cross-sectional level.variety seeking, brand loyalty, logit
- …
