Factor demand linkages, technology shocks, and the business cycle

This paper argues that factor demand linkages can be important for the transmission of both sectoral and aggregate shocks. We show this using a panel of highly disaggregated manufacturing sectors together with sectoral structural VARs. When sectoral interactions are explicitly accounted for, a contemporaneous technology shock to all manufacturing sectors implies a positive response in both output and hours at the aggregate level. Otherwise there is a negative correlation, as in much of the existing literature. Furthermore, we find that technology shocks are important drivers of the business cycle

SynGAP Regulates Steady-State and Activity-Dependent Phosphorylation of Cofilin

SynGAP, a prominent Ras/Rap GTPase-activating protein in the postsynaptic density, regulates the timing of spine formation and trafficking of glutamate receptors in cultured neurons. However, the molecular mechanisms by which it does this are unknown. Here, we show that synGAP is a key regulator of spine morphology in adult mice. Heterozygous deletion of synGAP was sufficient to cause an excess of mushroom spines in adult brains, indicating that synGAP is involved in steady-state regulation of actin in mature spines. Both Ras- and Rac-GTP levels were elevated in forebrains from adult synGAP+/- mice. Rac is a well known regulator of actin polymerization and spine morphology. The steady-state level of phosphorylation of cofilin was also elevated in synGAP+/- mice. Cofilin, an F-actin severing protein that is inactivated by phosphorylation, is a downstream target of a pathway regulated by Rac. We show that transient regulation of cofilin by treatment with NMDA is also disrupted in synGAP mutant neurons. Treatment of wild-type neurons with 25 µM NMDA triggered transient dephosphorylation and activation of cofilin within 15 s. In contrast, neurons cultured from mice with a homozygous or heterozygous deletion of synGAP lacked the transient regulation by the NMDA receptor. Depression of EPSPs induced by a similar treatment of hippocampal slices with NMDA was disrupted in slices from synGAP+/- mice. Our data show that synGAP mediates a rate-limiting step in steady-state regulation of spine morphology and in transient NMDA-receptor-dependent regulation of the spine cytoskeleton

Design of a metrology and characterization system for a compliant mechanisms course

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2008.Includes bibliographical references (leaf 34).The purpose of this thesis was to learn about creating an educational kit as a tool for teaching professional engineers in industry about the theory of Freedom and Constraint Topology (FACT), and the new types of flexures that can be designed using this process. The importance of this thesis lies in the benefits compliant mechanisms give to precision engineering. The impact, by improving the quality of designs capable by professional engineers by teaching them about using FACT to design flexures, will contribute to higher quality, more agile, and more reliable technology worldwide. The metrological systems designed for the kit were comprised of a system of sensors and data collection apparati to analyze the physical characteristics of a particular type of flexure known as a "screw flexure", a compliant mechanism that has a single degree of freedom with coupled translational and rotational motion. Using lead weights of V4 to 2 pounds and two Mitutoyo #ID-S1012E digital Dial Indicators, measurements were taken for the translational and rotational deflection of the screw flexure. The pitch of the screw flexure was found to be 10.512 in/rad, which was a 9.4% error from the expected value of 11.5 in/rad. The experimental setup was a successful tool for teaching FACT methodology in the specific case of the screw flexure.by Holly B. Laird.S.B

Invasive Species Management: Importers, Border Enforcement, and Risk

Invasive species are a negative externality associated with imported goods. Policies aimed at excluding pests associated with imports include pre-shipment treatment requirements, varied inspection schemes, treatment at the border, penalties, and import bans or restrictions. Existing policies are based on the reasoning that increased enforcement effort will result in higher detection levels, or more specifically, that increased inspection will result in a higher number of interceptions and in turn, higher compliance. In addition to a deterrence effect, however, under which importers respond to increased enforcement with increased due care with respect to pest control, importers may respond in ways that regulators do not intend. For example, importers may choose to not bring goods into the country, may ship a reduced amount, or may switch ports-of-entry. Moreover, different types of firms are likely to respond to enforcement in different ways. In this paper, we present a framework to analyze invasive species border enforcement given heterogeneous importers and ports. We develop a theoretical model of firm response to border enforcement, analyze both the intended and unintended effects of this enforcement for different types of firms, and evaluate the tradeoffs associated with location. Firms not only consider the changes in the levels of enforcement and other conditions at a single port, they consider the cost and benefit tradeoffs associated with location e.g., differences in inspection intensity or port-entry fees versus distance to port-of-entry and final market across ports and may switch ports. The result is that increased inspection intensity may not result the overall damages from invasive species introductions.Resource /Energy Economics and Policy,

A Follow-up of Job-Entry Training Completors at Madison Secondary School 1978-84

The research objectives for this study were: 1. To determine Job-entry training completors\u27 status, i.e., employment and/or continued education; 2. To evaluate the attainment of specific program goals; 3. To make recommendations for program/curriculum change

Photography: A Communication Tool

There are limited resources available for art teachers wishing to implement a photography curriculum that focus on social justice. Since the camera is a highly effective communicative tool, students should be encouraged to vocalize their understanding of how to better society through visual images. This research highlights the significance of photography and its ability to change the manner in which people view the world. The culminating product of this research is a downloadable PDF that features both contemporary and historical artists and organizations that have used photography to express social justice. The aim of this research is to promote photography to administrators, supporters, local communities, and students. Art teachers are encouraged to use the advocacy resource provided to promote social justice in their photography program

Toward an Expanded Conception of Law Reform: Sexual Harassment Law and the Reconstruction of Facts

This Note uses feminist reform of sexual harassment law to show how the reconstruction of factual descriptions can lead to change in the law. Part I describes the feminist methodology of consciousness raising and analyzes Catharine MacKinnon\u27s Sexual Harassment of Working Women as an example of a successful consciousness-raising tool. Part II discusses sexual harassment doctrine and presents a case study illustrating how changing the way legal decision makers think about facts can lead to law reform. Part III discusses how social construction theory aids understanding of changes in sexual harassment law