Sparse logistic principal components analysis for binary data

We develop a new principal components analysis (PCA) type dimension reduction method for binary data. Different from the standard PCA which is defined on the observed data, the proposed PCA is defined on the logit transform of the success probabilities of the binary observations. Sparsity is introduced to the principal component (PC) loading vectors for enhanced interpretability and more stable extraction of the principal components. Our sparse PCA is formulated as solving an optimization problem with a criterion function motivated from a penalized Bernoulli likelihood. A Majorization--Minimization algorithm is developed to efficiently solve the optimization problem. The effectiveness of the proposed sparse logistic PCA method is illustrated by application to a single nucleotide polymorphism data set and a simulation study.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS327 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Conflict: Conflicting images in Tallinn

“Conflict” is an artistic project that reconstructs conflicting images between the Soviet reality and tourism fantasy in Tallinn, the Estonian capital. In the city, images of the Old Town are represented as a national symbol and landmark in the context of global tourism. Different architecture, constructed since medieval period, is symbolized as authentic medievalness or Estonianness in consumer culture. Tourism marketing presents the architecture and the town itself as romantic and nostalgic signs. These signs of the city make it an exotic representation of Estonian city, which present a fantasy for foreign tourists. This routine to produce illusional images has been repeated within the tourist market system throughout the gradual transformation of the city. However, the remaining former Soviet architecture and Soviet minorities are situated in a crisis of disappearing. The architecture is gradually vanishing, along with the past memory of collectivity in Tallinn, because the city is transforming by converting the traces of the Soviet Union into a commercial context. Unlike the romantic city landscape of the Old Town, in reality the Soviet minorities suffer from the loss of memory, through the historical decay of Soviet architecture brought about due to nationalism and capitalism. In this city, the remaining Soviet and consumer culture are in conflict. After the Soviet Union collapsed, Linnahall, a public space constructed during the Soviet period, has been in semi-ruin. Some industrial factories which evoke memories of communal production have also been ruined or transformed to commercial places as Estonian land property shifted from state-owned land to privatization. Currently, both the remaining Soviet material traces and minorities in Tallinn are neglected by dominant ideologies of nationalism and capitalism. This contradictory situation between the Soviet and medieval traces occurs in conflicting social space between collectivity and privatization. Following this context of cultural conflict on specific sites and reflecting on my personal experience as a temporary outsider and a traveler, this project aims to reveal a contradiction of Tallinn landscape through a work of film. It asks: How are Soviet traces transformed and how do they disappear in conflicting social space? How can contradictory images from the space be presented through film? This thesis is composed of two parts: cultural research and artistic practice. The cultural research part investigates the socio political collision arising from historical and spatial transition as a research context through interviews, filming images and literature review. In other words, this part discusses ruined Soviet traces, such as Linnahall, factories and excluded soviet minorities as well as commercial tourism places, such as Old Town and churches in Old Town. In the artistic research part, the concept of conflict is based on Sergei Eisenstein’s film theory of montage. Eisenstein defined montage as a conflict to create new meaning through a dialectic approach of a film form. The conflict as montage uses the dialectic principle for creating dynamics. As the fundamental condition to create dynamics, different film elements need to be superimposed in contradictory relation. Following this sense, this principle of conflict is applied and extended to creating a film work through superimposing different moving images. The moving images used as elements for montage are created through two approaches, that are a departure from the theatrical approach of filmmaking used by Eisenstein. The first approach is improvisational shooting, without plot or planning. The second is to reuse existing film elements by detouring. Both ways intend to change the natural original context to another through montage. This extended montage is used as a tool for revealing conflicting images from the cultural research part: old and new, insider and outsider, local and global in contradictory relation between Soviet traces and current transformed landscape, which is superimposed to create new meaning

Three essays on Renewable Portfolio Standards

The first essay investigates the technical efficiencies of South Korean solar photovoltaic (PV) power plants by type: ground-mounted PV (GPV) and rooftop PV (BPV). The two-step stochastic frontier analysis (SFA) of the true-random effects model is used to capture heterogeneity. In the results, the first-order input parameters are positive and significant, satisfying the monotonicity condition for valid production functions, except for the daily sunshine hours. The average technical efficiency (TE) scores for BPV and GPV are 0.995 and 0.991, respectively, it can be concluded that there is no evidence that many plants of these types are significantly lagging behind the most efficient producers of the type. The estimates of mean technology gap ratio (TGR) values are very close to 1, and the meta-technology efficiency (MTE) scores are 0.991 for the BPV and 0.985 for the GPV. There is a small difference in TEs, TGRs, and input use. The second essay examines how the Renewable Portfolio Standards (RPS) policy influences the decision-making process of manufacturers regarding the choice between staying in their current country or relocating to a foreign country in response to initiatives such as RE100. Three-stage game is considered in which three player groups participate: the social net benefit maximizing government sets the RPS target in the first stage, the profit maximizing RPS obligors (utilities) makes decisions regarding the amount of renewable electricity they will provide in the second stage, and the profit maximizing firms supplying RE100 companies determine to remain in their current country or relocate to another country offering cheaper renewable electricity in the third stage. The findings indicate that a rational government will choose a target share that maintains employment as long as it brings a non-negative net benefit. Moreover, there exists a range where between domestic and foreign renewable energy prices to determine domestic production, even when domestic prices are higher. By increasing the price of non-renewable electricity, it is possible to subsidize renewable electricity depending on cost transparency. The exogenous variables determine the subgame perfect equilibrium. The third essay investigates the impact of RPS policies on total primary crop acreage in the United States. Our empirical framework is based on the premise that acreage is influenced by climatic factors, farmers' crop management practices, and land allocation decisions, while considering input and expected production prices. We extend the framework to incorporate the influence of renewable electricity policy (RPS) and other agricultural policy (CRP). The coefficients of the composite price index are positively related to acreage, while the coefficients of the fertilizer price index exhibit a negative relationship. The estimated output price elasticities range from 0.297 to 0.329, and the elasticities from the models considering electricity market characteristics show similar magnitudes, approximately 0.30. The RPS electricity supply target is found to significantly reduce acreage, although the actual magnitude of reduction is relatively modest, estimated at around 24 to 26 acres per 1000 MWh. Crop acreage changes by target level of renewable electricity is similar to STRATA's data, however it can be seen as overestimated based on the National Renewable Energy Laboratory (NREL)'s data.Includes bibliographical references

Phospholipase Cγ1 (PLCγ1) controls osteoclast numbers via colony-stimulating factor 1 (CSF-1)-dependent diacylglycerol/β-catenin/cyclinD1 pathway

Phospholipases Cγ (PLCγ) 1 and 2 are a class of highly homologous enzymes modulating a variety of cellular pathways through production of inositol 1,4,5-trisphosphate and diacylglycerol (DAG). Our previous studies demonstrated the importance of PLCγ2 in osteoclast (OC) differentiation by modulating inositol 1,4,5-trisphosphate-mediated calcium oscillations and the up-regulation of the transcription factor NFATc1. Surprisingly, despite being expressed throughout osteoclastogenesis, PLCγ1 did not compensate for PLCγ2 deficiency. Because both isoforms are activated during osteoclastogenesis, it is plausible that PLCγ1 modulates OC development independently of PLCγ2. Here, we utilized PLCγ1-specific shRNAs to delete PLCγ1 in OC precursors derived from wild type (WT) mice. Differently from PLCγ2, we found that PLCγ1 shRNA significantly suppresses OC differentiation by limiting colony-stimulating factor 1 (CSF-1)-dependent proliferation and β-catenin/cyclinD1 levels. Confirming the specificity toward CSF-1 signaling, PLCγ1 is recruited to the CSF-1 receptor following exposure to the cytokine. To understand how PLCγ1 controls cell proliferation, we turned to its downstream effector, DAG. By utilizing cells lacking the DAG kinase ζ, which have increased DAG levels, we demonstrate that DAG modulates CSF-1-dependent proliferation and β-catenin/cyclinD1 levels in OC precursors. Most importantly, the proliferation and osteoclastogenesis defects observed in the absence of PLCγ1 are normalized in PLCγ1/DAG kinase ζ double null cells. Taken together, our study shows that PLCγ1 controls OC numbers via a CSF-1-dependent DAG/β-catenin/cyclinD1 pathway