Coursework Completed at Wharton ('06 to '08)

Note: Adam Powell is on dissertation status and is no longer taking courses.
Areas of Study
Economics
Health Care Systems
Management
Operations & Information Management
Statistics
 

Economics

ECON 681 Microeconomic Theory Basic tools of microeconomic theory: consumer choice, firm behavior, partial and general equilibrium theory.
ECON 682 Game Theory and Applications A graduate level introduction to decision making under uncertainty, applied game theory, and information economics.

Health Care Systems

HCMG 841 Health Services System This course provides an overview of the evolution, structure and current issues in the health care system. It examines the unique features of health care as a product, and the changing relationships between patients, physicians, hospitals, insurers, employers, communities, and government. The course examines three broad segments of the health care industry: payers, providers and suppliers. Within the payer segment, the course examines the sources and destinations of spending, managed care (HMOs, PPOs), employer based health insurance, technology assessment, payer strategy, and efforts to pay for the elderly, the poor & the medically indigent. Within the provider segment, the course examines the impact of cost containment and competition on hospitals and integrated delivery systems, long term care and disease management, and the important role of epidemiology in assessing population health needs and risks. Within the supplier segment, the course will examine developments in the biotechnology, pharmaceutical, medical devices, genomics and IT industries. This is a required course for Wharton Graduate Health Care Management majors; it counts as an elective course for all other Wharton Graduate students.
HCMG 845 Managed Care and Market Structure This course, co-taught by Professor Rob Burns and Brad Fleugel of Aetna, focuses on two interrelated topics: managed care and market structure. The section on managed care covers strategic planning and marketing of managed care services, operational issues in developing a managed care network, actuarial issues, and the management of physician behavior. The section on health care market structure analyzes strategies of vertical integration and horizontal integration (M&As), and their attempt to alter the balance of power in local healthcare markets. The section also analyzes the operational issues in managing cost and quality in an integrated system, integration along the supply chain, and the performance of these systems.
HCMG 859 Comparative Health Care Systems This course examines the structure of health care systems in different countries, focusing on financing, reimbursement, delivery systems and adoption of new technologies. We study the relative roles of private sector and public sector insurance and providers, and the effect of system design on cost, quality, efficiency and equity of medical services. Some issues we address are normative: Which systems and which public/private sector mixes are better at achieving efficiency and equity? Other issues are positive: How do these different systems deal with the touch choices, such as decisions about new technologies? Our main focus is on the systems in four large OECD countries-Germany, Canada, Japan, and the United Kingdom-but we also look at other countries with interesting systems- including Italy, Chile, and Singapore. We will draw lessons for the U.S. from foreign experience and vice versa.
HCMG 900 Proseminar in Health Services Research This seminar will explore the theoretical and the empirical literature on the diffusion of innovation. We will consider innovations of various sorts - those embodied in concrete "products" as well as those that are organizational and/or managerial in nature. The principal objective of the seminar will be to understand those factors that facilitate the diffusion process as well as those that slow it down. We will read work in many fields, including organization theory, consumer psychology, marketing, sociology and geography. Each student will be responsible for designing a study of the diffusion of an innovation or set of innovations of particular interest to him or her. The seminar is offered by the Department of Health Care Systems, and many of the examples of empirical studies will come from health services research.
HCMG 901 Health Care Cost Effectiveness Analysis & Cost Benefit Analysis The purpose of this doctoral level course is to investigate the theory and practice of cost-benefit and cost-effectiveness analysis as applied to health care. The three techniques to be examined are cost-effectiveness analysis with single dimensional outcomes, cost effectiveness analysis with multiple attributes (especially in the form of Quality Adjusted Life Years), and economic cost-benefit analysis. Valuation of mortality and morbidity relative to other goods will be emphasized. Students will be expected to develop written critiques of articles in the literature, and to design a new application of one of the techniques as a term project.
HCMG 903 Economics of Health Cost & Policy This course applies basic economic concepts to analyze the health care market and evaluate health policies. The course begins with an analysis of the demand for health, the derived demand for medical care and the demand for health insurance. The second part of the course examines the supply of medical care by physicians and hospitals, medical technology, and the role of managed care organizations. The implication of adverse selection, moral hazard, externalities, and asymmetric information will be explored. The third part of the course examines the rationale for government intervention in medical markets as well as the effectiveness and efficiency of various health policies, including: Medicare, Medicaid, price regulation of hospitals, physician payment reform, medical malpractice, uncompensated care, and physician manpower planning.

Management

MGMT 900 The Economic Foundations of Management Research This seminar explores the foundation questions of the strategy field-the questions that keep reappearing in ever-changing guises when specific strategic issues are confronted in a variety of contexts. There are substantial social science literatures dealing with most of these questions. The major purpose of the seminar is to expose students to samples of these literatures and to point out their relevance to strategy. The contributions of economic thinking to the strategy field receive disproportionate attention, but not to the point where they crowd other disciplines or strategy itself off the stage.
MGMT 925 Corporate Strategy The seminar is built around published empirical research in corporate strategy. Articles for discussion will be drawn from journals in several fields, including economics, the behavioral sciences, management science, business administration, and elsewhere. Students will take turns leading the seminar discussion (with the help of the instructor).
MGMT 933 The Psychological and Sociological Foundations of Research in Management Management 933 provides students with discipline-based "foundations of" theory and research. Specifically, this course will explore the intellectual history of psychology and sociology in management beginning in the early 1900s to the 1970's. Topics include: the social context of individual behavior, motivation and job satisfaction, organizational context and bureaupathology, industrial and organizational selection, training and development.
MGMT 937 PhD Seminar on Entrepreneurship The seminar seeks to expose students to theoretical and empirical perspectives on entrepreneurship research. We will focus on the main questions that define the field and attempt to critically examine how, using a range of methodologies, researchers have approached these questions. As we review the literature, we will seek to identify promising research areas, which may be of interest to you in the context of your dissertation research. In addition to addressing the content of the received literature, we will examine the process of crafting research papers and getting them published in top tier journals. Towards that end we will characterize the key elements of high impact papers and review the development process of such studies.
MGMT 951 Micro-Organizational Behavior This course is a research seminar on micro and meso theories of organizational behavior. The main objective of this seminar is to examine theoretical statements of individual and group behavior in organizations, to examine how organizational variables affect such behavior, to discuss and evaluate critically some empirical studies based on these theories, and finally, to understand the emerging general direction of the area.
MGMT 953 Research Methods in Management This seminar introduces the doctoral student to the ways & means of doing research and delivering it in the form of papers and/or monographs. The course offers an overview of theory development, the logic of research, the relationship between theoretical & empirical constructs, a wide variety of specific research methodologies, and the scholarly publication process.

Operations & Information Management

OPIM 900 Decision Processes Normative and descriptive models of decision making, including expected utility theory, behavioral models of choice and related empirical and experimental evidence. Intertemporal choice models, ambiguity and uncertainty. Applications in contracting/incentive design, consumer choice, finance, and public policy.
OPIM 940 Operations Management Introduction to concepts, models, and theories relevant to the management of the processes required to provide goods or services to consumers. Includes, production, inventory and distribution functions, supply chain management, scheduling of service or manufacturing activities, facility capacity planning and design, product design. The methodological basis for the course includes management science, economic theory, organization theory.

Statistics

STAT 500 Applied Regression & ANOVA An applied graduate level course in multiple regression and analysis of variance for students who have completed an undergraduate course in basic statistical methods. Emphasis is on practical methods of data analysis and their interpretation. Covers model building, general linear hypothesis, residual analysis, leverage and influence, one-way ANOVA, two-way ANOVA, and factorial ANOVA. Primarily for doctoral students in the managerial, behavioral, social and health sciences.
STAT 501 Introduction to Nonparametric Methods and Log-linear Models An applied graduate level course for students who have completed an undergraduate course in basic statistical methods. Covers two unrelated topics: log linear and logit models for discrete data and nonparametric methods for non normal data. Emphasis is on practical methods of data analysis and their interpretation.

Coursework Completed at MIT ('02 to '06)

Areas of Study
Chemistry
Computer Science
Economics
Foreign Languages and Literatures
Linguistics & Philosophy
Management Science
Mathematics
Physics
Writing
 

Chemistry

5.111 Principles of Chemical Science Introduction to chemistry, with emphasis on basic principles of atomic and molecular electronic structure, thermodynamics, acid-base and redox equilibria, chemical kinetics, and catalysis. Introduction to the chemistry of biological, inorganic, and organic molecules.

Computer Science

6.001 Structure and Interpretation of Computer Programs Control of complexity in large programming systems. Building abstractions: computational processes; higher-order procedures; compound data; and data abstractions. Controlling interactions: generic operations; self-describing data; message passing; streams and infinite data structures; and object-oriented programming. Meta-linguistic abstraction: interpretation of programming languages; machine model; compilation; and embedded languages. Substantial weekly programming assignments are an integral part of the subject.
6.034 Artificial Intelligence Introduces representations, techniques, and architectures used to build applied systems and to account for intelligence from a computational point of view. Applications of rule chaining, heuristic search, constraint propagation, constrained search, inheritance, and other problem-solving paradigms. Applications of identification trees, neural nets, genetic algorithms, and other learning paradigms. Speculations on the contributions of human vision and language systems to human intelligence.
6.041 Probabilistic Systems Analysis Modeling, quantification, and analysis of uncertainty. Formulation and solution in sample space. Random variables, transform techniques, simple random processes and their probability distributions, Markov processes, limit theorems, and elements of statistical inference. Interpretations, applications, and lecture demonstrations.

Physics

8.01X Physics I Introduces classical mechanics. Space and time: straight-line kinematics; motion in a plane; forces and equilibrium; experimental basis of Newton's laws; particle dynamics; universal gravitation; collisions and conservation laws; work and potential energy; vibrational motion; conservative forces; inertial forces and non-inertial frames; central force motions; rigid bodies and rotational dynamics
8.02X Physics II Main emphasis on electricity and magnetism. Topics include currents and DC circuits; capacitance, resistance, and nonsteady currents; Coulomb's Law and electrostatic fields; Gauss's Law; electric potential; magnetic fields of currents; electromagnetic induction; magnetism and matter; AC circuits and resonance; Maxwell's equations; electromagnetic fields in space; electromagnetism and relativity; electromagnetic radiation as waves and photons. Kits of equipment are provided for the performance of a relevant take-home experiment as part of the homework each week.

Economics

14.01 Principles of Microeconomics  Introduces microeconomic concepts and analysis, supply and demand analysis, theories of the firm and individual behavior, competition and monopoly, and welfare economics. Applications to problems of current economic policy.
14.02 Principles of Macroeconomics Provides an overview of macroeconomic issues: the determination of output, employment, unemployment, interest rates, and inflation. Monetary and fiscal policies are discussed. Important current policy debates such as social security, the public debt, and international economic issues are critically explored. Introduces basic models of macroeconomics and illustrates principles with the experience of the US and foreign economies.
14.03 Intermediate Applied Microeconomics Presents basic theory and applications of consumer and producer behavior and welfare analysis at an intermediate level. Emphasizes applications, including the measurement of productivity, rationing, insurance markets, and intertemporal behavior.
14.20 Industrial Organization and Public Policy Analyzes the structure, behavior, and performance of industrial markets in the US economy. Topics include the measurement of monopoly power, behavior of firms in oligopoly markets, static and dynamic measures of market performance, antitrust, research and development, and theory of the firm.
14.21J Health Economics Applies theoretical and empirical tools of economics to problems of health and medical care delivery. Concentrates on selected problems such as the welfare economics of "health" as a commodity, hospitals and the nonprofit sector, human capital and medical manpower, and innovation in medicine.
14.286J Health Economics Seminar Advanced subject in economics of health care sector. Considers selected topics in depth, such as design and financing of health insurance, behavior of nonprofit hospitals, role of competition in the medical care market, determinants of technological change, and effects of government regulations.

Management Science

15.053 Optimization Methods in Management Science Introduces students to the theory, algorithms, and applications of optimization. The optimization methodologies include linear programming, network optimization, integer programming, and decision trees. Applications to logistics, manufacturing, transportation, marketing, project management, and finance.
15.075 Statistical Thinking and Data Analysis Introduces statistical data analysis, concentrating on techniques used in management science and finance. Topics chosen from: statistical graphics; sampling; estimation; hypothesis testing; linear and logistic regression; analysis of variance; categorical data analysis; and classification. SAS, S+ or similar statistics package used for computing.
15.141J Economics of the Health Care Industries Focuses on economic issues in various health care industries, such as the pharmaceutical, biotech and medical device industries. Differences between health care and other industries, regulatory issues involving establishing efficacy and cost-effectiveness of treatments, strategic issues in global marketing and pricing, use of e-commerce and information technology, and formation and management of various alliances, are addressed. Visiting speakers come from academia, government and industry.
15.279 Management Communication for Undergraduates Required seminar for Management Science majors to develop the writing, speaking, teamwork, and interpersonal communication skills necessary for managers. Students learn communication principles, strategies, and methods through discussions, exercises, examples, and cases. Assignments include writing memos and business letters, and giving oral presentations in labs outside of class. A major project is the production of a team report and presentation on a topic of interest to a managerial audience.
15.390 New Enterprises Covers the process of identifying and quantifying market opportunities, then conceptualizing, planning, and starting a new, technology-based enterprise. Topics include: opportunity assessment, the value proposition, the entrepreneur, legal issues, entrepreneurial ethics, the business plan, the founding team, seeking customers and raising funds. Students develop detailed business plans for a startup. Intended for students who want to start their own business, further develop an existing business, be a member of a management team in a new enterprise, or better understand the entrepreneur and the entrepreneurial process.
15.301 Managerial Psychology Laboratory  Core subject for students majoring in management science. Surveys individual and social psychology and organization theory interpreted in the context of the managerial environment. Laboratory involves projects of an applied nature in behavioral science. Emphasizes use of behavioral science research methods to test hypotheses concerning decision making, group behavior and organizational behavior. Instruction and practice in communication include report writing, team projects, and oral and visual presentation.
15.358 The Software Business Seminar-style subject for those interested in founding or growing an enterprise or consumer software company (products, services or both), or working as a software company manager, product or program manager, or industry analyst. Examine approaches used for organization and product development at successful companies ranging from Microsoft and IBM to a variety of relatively new companies. History of software as a business as well as key trends in different software markets. Student-teams help teach weekly sessions and analyze "interesting companies" selected by students which form the basis for team projects.
15.401 Finance Theory I Core theory of modern financial economics and financial management, concentrating on capital markets and investments. Required for most finance electives and for the Financial Management and Financial Engineering tracks. Topics: functions of capital markets and financial intermediaries; fixed income investments; diversification and portfolio selection; valuation theory and equilibrium pricing of risky assets; the theory of efficient markets; and an introduction to derivatives.
15.501 Introduction to Financial and Managerial Accounting Studies basic concepts of financial and managerial reporting. Viewpoint is that of readers of financial and managerial reports rather than the accountants who prepare them.
15.561 Information Technology Essentials Subject covers technology concepts and trends underlying current and future developments in information technology, and fundamental principles for the effective use of computer-based information systems. Special emphasis on networks and distributed computing, including the web. Other topics include: hardware and operating systems, software development tools and processes, relational databases, security and cryptography, enterprise applications and business process redesign, and electronic commerce. Hands-on exposure to web, database, and graphical user interface (GUI) tools.
15.564 IT Essentials II: Advanced Technologies for Digital Business in the Knowledge Economy Advanced information technologies for digital business in the era of the knowledge economy, combining depth and breadth. Particular technologies, their central underlying concepts, and discussion of their functional applications. Technologies emphasis on second generation of fundamental Web technologies, including XML, services, and automated knowledge bases such as semantic web. Applications emphasis is on intra- and inter- enterprise business process automation across numerous areas of business and management, including B2B, supply chain, finance, marketing, and customer/partner relationships. Considers strategic impacts, industry standards, and entrepreneurial opportunities. Draws upon artificial intelligence and distributed systems theory. Second-term half subject.
15.565J Integrating Information Systems: Technical, Strategic, and Organizational Factors Emphasis on modern communications and Internet technologies and database and web technologies, and their role in supporting the integration of information systems. Presents frameworks for understanding integrating concepts and the strategic and organizational factors impacting success of IT in business. Issues addressed include technical factors: local-area, wide-area, and Internet communications networks, distributed databases, data extraction from web sites, semantic web, semantic reconciliation among heterogeneous sources; strategic factors: globalization and integration of information, competitive forces, interlinked value chains; organizational factors: loosely coupled organizations, development of standards, motivating strategic alliances.
15.568 Management Information Systems Concepts, frameworks, tools, techniques, and processes that assist management in its interaction with and direction of computer-based information systems today. Discusses the impact of the Internet, changes in the IT industry, and changes in other industries as a result of IT. Also notes the redesign of information flows to meet the needs of both control and empowerment in the era of the global information infrastructure and networked organizations. Emphasizes managerial point of view and organizational issues involved in managing a firm's information resources.
15.665 Power and Negotiation Provides understanding of the theory and processes of negotiation as practiced in a variety of settings. Designed for relevance to the broad spectrum of bargaining problems faced by the manager and professional. Allows students an opportunity to develop negotiation skills experientially and to understand negotiation in useful analytical frameworks. Emphasizes simulations, exercises, role playing, and cases.
15.812 Marketing Management Provides an overview of the major areas in marketing, including the assessment of consumer needs, market segmentation, targeting and positioning, product design and branding, pricing, advertising, forecasting demand, survey design, and consumer psychology. Coverage includes lectures, case studies, and class demonstrations.
15.843 Special Seminar in Marketing: Advertising Provides a managerial perspective on making marketing communications decisions. Promotes understanding of the issues in planning and evaluating marketing communication
campaigns. Introduces theories necessary for understanding marketing communications.
15.966 Special Seminar in Management: Managing in Adversity Consists of a series of guest lectures by CEOs of companies that have experienced adversity. Uses the case method.
15.970 Special Seminar in Management: Digital Innovations This applied social science and media arts seminar surveys the blossoming arena of digital-artifact enabled experimental sociology. It emphasizes both (a) Technology Testbeds – experimenting with research lab prototypes and corporate pre-production products in a sample human organizational population and carefully observing the social consequences, and (b) Sociometrics – using digital artifacts to better observe and measure the complex social reality of interesting human systems.
15.971 Special Seminar in Management: Developmental Entrepreneurship & Social Innovation Developmental Entrepreneurship & Social Innovation (DESI) is a Fall semester seminar on building entrepreneurial ventures, especially using the new generation of mobile information and communications technologies, with particular emphasis on those exponential technologies and ventures which can cause major positive social change throughout the world.

Mathematics

18.023 Calculus with Applications Calculus of several variables, emphasizing applications. Vector algebra, partial differentiation, multiple integrals, and vector calculus. Asymptotic and numerical methods.
18.03 Differential Equations Study of ODE's, including modeling physical systems. Solution of first-order ODE's by analytical, graphical and numerical methods. Linear ODE's, especially second order with constant coefficients. Undetermined coefficients and variation of parameters. Sinusoidal and exponential signals: oscillations, damping, resonance. Complex numbers and exponentials. Fourier series, periodic solutions. Delta functions, convolution, and Laplace transform methods. Matrix and first order linear systems: eigenvalues and eigenvectors. Non-linear autonomous systems: critical point analysis and phase plane diagrams.
18.06 Linear Algebra Basic subject on matrix theory and linear algebra, emphasizing topics useful in other disciplines, including systems of equations, vector spaces, determinants, eigenvalues, similarity, and positive definite matrices. Applications to least-squares approximations, stability of differential equations, networks, Fourier transforms, and Markov processes. Uses MATLAB.

Foreign Languages and Literatures

21F.027J Visualizing Cultures Examines how visual images shape the identity of peoples and cultures. A prototype digital project looking at American and Japanese graphics depicting the opening of Japan to the outside world in the 1850s is used as a case study to introduce the conceptual and practical issues involved in visualizing cultures. Guest lecturers include professionals engaged in various aspects of collecting, analyzing, and presenting graphic images. Students create and present a project involving visualized cultures.
21F.035 Topics in Culture and Globalization The concept of globalization fosters the understanding of the interconnectedness of cultures and societies geographically wide apart such as America, Europe, Asia, and Africa. Subject scans existing debates over globalization. Explores how globalization impacts everyday life in the First and Third World; how globalization leads to a common cosmopolitan culture; the emergence of a global youth culture; and religious, social, and political movements that challenge globalization.
21F.036 Advertising and Popular Culture: East Asian Perspectives Examines modern advertising culture in East Asia (with a week devoted to India) with an emphasis on post-socialist China. Topics include the rise of transnational advertising agencies in East Asia since the 1980s; advertising and identity formation; the production of brand culture and its impact on youth culture; music marketing; the new paradigm of neo neo-tribes; media and advertising, and mobile culture and branding. Case studies of famous advertising campaigns for beer and beverage brands, clothing brands, and Internet portal brands. Lab sessions on how to brand your own imaginary product step by step. View award-winning ads presented at the Asia/Pacific Advertising Festivals and Chinese television commercials.
21F.067J Cultural Performances of Asia Topics include the all-female Takarazuka Revue, all-male Kabuki, high fashion of Comme Des Garcons, samurai masculinity in film, Asian representations online. Emphasis on Japan, but other Asian cultures considered. Examines cultural performances of Asia, including both traditional and contemporary forms, in a variety of genres, with particular attention to gender issues. Explores the communicative power of performances with attention to the ways performers, media, cultural settings, and audiences interact. Considers ways representation of cultural difference is altered through processes of globalization. Performances viewed live when possible, but also relies on video, audio, and online materials.

Writing

21W.735 Writing and Reading the Essay Exploration of formal and informal modes of writing nonfiction prose. Extensive practice in composition, revision, and editing. Reading in the literature of the essay from the Renaissance to the present, with an emphasis on modern writers. Classes alternate between discussion of published readings and workshops on student work.
21W.749 Documentary Photography and Photojournalism: Still Images of a World in Motion Designed to increase students' understanding of, appreciation for, and ability to do documentary photography and photojournalism. Each three-hour class is divided between a discussion of issues and readings, and a group critique of students' projects. Students must have their own photographic equipment and be responsible for processing and printing: either by student or commercial lab. Students must show basic proficiency with their equipment. Readings include Susan Sontag, Robert Coles, Ken Light, Eugene Richards, and others. Previous photographic experience required.
21W.765J Interactive and Non-Linear Narrative: Theory and Practice
 
Techniques of creating narratives that take advantage of the flexibility of form offered by the computer. Study of the structural properties of book-based narratives that experiment with digression, multiple points of view, disruptions of time and of storyline. Analysis of the structure and evaluation of the literary qualities of computer-based narratives including hypertexts, adventure games, and classic artificial intelligence programs like Eliza. With this base, students use authoring systems to model a variety of narrative techniques and to create their own fictions.
21W.778 Science Journalism An introduction to print daily journalism and news writing, focusing on science news writing in general, and medical writing in particular. Emphasis is on writing clearly and accurately under deadline pressure. Class discussions involve the realities of modern journalism, how newsrooms function, and the science news coverage in daily publications. Discussions of, and practice in, interviewing and various modes of reporting. In class, students write numerous science news stories on-deadline. There are additional longer writing assignments outside of class.
21W.784 Becoming Digital: Writing about Media Change Explores ramifications of the changing way we communicate, do business, gather information, and find entertainment. Problems that arise in the transition from pre-digital to digital media. Topics include manipulation of digital images, the ethics of anonymity on the Internet, the social repercussions of the computer, and the allure of computer gaming. Sources include readings and film. Frequent writing and revision, an oral presentation, and intensive class participation are required.
21W.785 Communicating in Cyberspace Subject covers the analysis, design, implementation, and testing of various forms of digital communication based on group collaboration. Students are encouraged to think about the Web and other new digital interactive media not just in terms of technology but also broader issues such as language (verbal and visual), design, information architecture, communication and community. Students work in small groups on a semester-long project of their choice. Various written and oral presentations document project development.
21W.ThT Writing and Humanistic Studies Pre-Thesis Tutorial Definition of and early stage work on a thesis project leading to 21W.ThU Undergraduate Thesis in Writing. Taken during the first term of a student's two-term commitment to the thesis project. Student works closely with an individual faculty tutor. Required of all students pursuing a full major in Course XXIW.
21W.ThU Writing and Humanistic Studies Thesis Completion of work on the senior major thesis under the supervision of a faculty tutor. Includes oral presentation of the thesis progress early in the term, assembling and revising the final text, and a final meeting with a committee of faculty evaluators to discuss the successes and limitations of the project. Required of students pursuing a full major in Course XXIW.

Linguistics & Philosophy

24.04J Justice An examination of alternative theories of justice—utilitarianism, rights theories, social contract theory, and communitarianism—and the implications of those theories for problems of liberty, equality, and community. Readings drawn principally from the work of contemporary political philosophers, including Rawls, Nozick, Dworkin, Walzer, MacIntyre, and Buchanan.