Colloquium on Solid State Devices

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Machine Learning in Automated Text Categorization

The automated categorization (or classification) of texts into predefined categories has witnessed a booming interest in the last ten years, due to the increased availability of documents in digital form and the ensuing need to organize them. In the research community the dominant approach to this problem is based on machine learning techniques: a general inductive process automatically builds a classifier by learning, from a set of preclassified documents, the characteristics of the categories. The advantages of this approach over the knowledge engineering approach (consisting in the manual definition of a classifier by domain experts) are a very good effectiveness, considerable savings in terms of expert manpower, and straightforward portability to different domains. This survey discusses the main approaches to text categorization that fall within the machine learning paradigm. We will discuss in detail issues pertaining to three different problems, namely document representation, classifier construction, and classifier evaluation.Comment: Accepted for publication on ACM Computing Survey

In vivo bioimaging with tissue-specific transcription factor activated luciferase reporters.

The application of transcription factor activated luciferase reporter cassettes in vitro is widespread but potential for in vivo application has not yet been realized. Bioluminescence imaging enables non-invasive tracking of gene expression in transfected tissues of living rodents. However the mature immune response limits luciferase expression when delivered in adulthood. We present a novel approach of tissue-targeted delivery of transcription factor activated luciferase reporter lentiviruses to neonatal rodents as an alternative to the existing technology of generating germline transgenic light producing rodents. At this age, neonates acquire immune tolerance to the conditionally responsive luciferase reporter. This simple and transferrable procedure permits surrogate quantitation of transcription factor activity over the lifetime of the animal. We show principal efficacy by temporally quantifying NFκB activity in the brain, liver and lungs of somatotransgenic reporter mice subjected to lipopolysaccharide (LPS)-induced inflammation. This response is ablated in Tlr4(-/-) mice or when co-administered with the anti-inflammatory glucocorticoid analogue dexamethasone. Furthermore, we show the malleability of this technology by quantifying NFκB-mediated luciferase expression in outbred rats. Finally, we use somatotransgenic bioimaging to longitudinally quantify LPS- and ActivinA-induced upregulation of liver specific glucocorticoid receptor and Smad2/3 reporter constructs in somatotransgenic mice, respectively

The multiplicity of performance management systems:Heterogeneity in multinational corporations and management sense-making

This field study examines the workings of multiple performance measurement systems (PMSs) used within and between a division and Headquarters (HQ) of a large European corporation. We explore how multiple PMSs arose within the multinational corporation. We first provide a first‐order analysis which explains how managers make sense of the multiplicity and show how an organization's PMSs may be subject to competing processes for control that result in varied systems, all seemingly functioning, but with different rationales and effects. We then provide a second‐order analysis based on a sense‐making perspective that highlights the importance of retrospective understandings of the organization's history and the importance of various legitimacy expectations to different parts of the multinational. Finally, we emphasize the role of social skill in sense‐making that enables the persistence of multiple systems and the absence of overt tensions and conflict within organizations

The Influence of a Firms\u27 Business Strategy on the Downside Risk of Earnings, Accruals and Cash Flow

This study examines whether a firm\u27s business strategy is an underlying determinant of downside risk in accounting earnings and its components. Based on organizational theory we predict that firms following an innovative prospector strategy exhibit lower profitability tendencies than firms following a cost-oriented defender strategy. Further, we anticipate that these strategies are asymmetrically positioned towards environmental uncertainty, with defenders focusing their efforts to efficiency, cost control, and minimizing exposure to downside risk, whereas prospectors direct their resources to flexibility, innovation, and maximizing the growth potential through aggressive expansion to new product markets. We find that prospectors are indeed less profitable than defenders. We also demonstrate that prospectors have greater total and downside earnings risk. Finally, we decompose earnings into accruals and cash flow and show that the higher exposure of prospectors to earnings downside risk is driven by the cash flow component rather than the accrual component. Collectively, our results suggest that considering how strategy interacts with financial reporting attributes is a useful way for evaluating a firms\u27 risk profile

Pseudohyperphosphorylation has differential effects on polymerization and function of tau isoforms

The microtubule-associated protein tau exists as six isoforms created through the splicing of the second, third, and tenth exons. The isoforms are classified by their number of N-terminal exons (0N, 1N or 2N) and by their number of microtubule-binding repeat regions (3R or 4R). Hyperphosphorylated isoforms accumulate in insoluble aggregates in Alzheimer’s disease and other tauopathies. These neurodegenerative diseases can be categorized based on the isoform content of the aggregates they contain. Hyperphosphorylated tau has the general characteristics of an upward electrophoretic shift, decreased microtubule binding, and an association with aggregation. Previously we have shown that a combination of seven pseudophosphorylation mutations at sites phosphorylated by GSK-3β, referred to as 7-Phos, induced several of these characteristics in full-length 2N4R tau and led to the formation of fewer but longer filaments. We sought to determine whether the same phosphorylation pattern could cause differential effects in the other tau isoforms, possibly through varied conformational effects. Using in vitro techniques, we examined the electrophoretic mobility, aggregation properties and microtubule stabilization of all isoforms and their pseudophosphorylated counterparts. We found that pseudophosphorylation affected each isoform, but in several cases certain isoforms were affected more than others. These results suggest that hyperphosphorylation of tau isoforms could play a major role in determining the isoform composition of tau aggregates in disease