The School of Social Welfare Ph.D. Curriculum
The curriculum is designed to accomplish three objectives:
- To enable students to acquire a core of advanced knowledge of social work practice theory, social policy, research methods, and statistics,
- To permit students to obtain specialized knowledge in areas of their own choosing, and
- To facilitate the contribution of students to knowledge-building and education in social work and social welfare.
The program of study for the doctoral degree consists of 36 credit hours. It can be completed within three years although most students take longer because they wish (or need) to remain employed while completing their academic requirements and the dissertation. Students have eight years to complete the degree.
Students who do not have the M.S.W. degree will be required to successfully complete two courses in the School's M.S.W. program, SSW 620 Micro Practice in Social Work I and SSW 600 Social Welfare Policy and Services, as prerequisites to the two doctoral proseminars on social welfare policy and practice. Credit for these master's level courses will not count for the 36 required credits for the Ph.D. degree. Students can be excused from taking SSW 600 upon successful completion of a place out examination.
Required courses include four proseminars and two statistics courses. Students with the M.S.W. must also take two courses outside the School of Social Welfare, which along with electives and optional internships in teaching, practice, and research, enable students to develop further their own individualized interests. Other requirements include proficiency in a foreign language or in computer skills, a qualifying examination, a doctoral essay, a predissertation research requirement, and a dissertation.
These requirements provide a base and framework for an individualized program of study. Students are encouraged to build their programs around their dissertation interests, beginning with proseminars. For example, a students interested in prevention of adolescent pregnancy may use written assignments and class presentations in each of the proseminars to advance his or her interest in the topic to analyze social policies relating to adolescent pregnancy, to learn about prevention theory and approaches, and to develop a research proposal relating to adolescent pregnancy or its prevention.
The proseminars are designed to provide students with knowledge and skill in specified areas as well as to facilitate their pursuit of individual interests through selection of topics for presentations, exercises, and term papers. Normally, two proseminars (823 and 862) are offered in the fall semester and the other two (826 and 863) in the spring semester.
The proseminars are:
Social Work Practice Theory (3)
Social Welfare Policy (3)
Social Welfare Research (3)
SSW 863 Applications of Advanced Methods in Social Welfare Research (3)
The statistics requirement is met by successfully completing two approved courses. It is recommended, but not required, that students complete both statistics courses in the same department or school, preferably in the School of Social Welfare. Students may choose one of the following four 2-course sequences to fulfill the statistics requirement.
(School of Social Welfare)
SSW 679 Statistics and Data Analysis I (4)
SSW 687 Statistics and Data Analysis II (4)
Department of Biometry and Statistics
(School of Public Health)
STA 552 Principles of Statistical Inference I (3)
STA 553 Principles of Statistical Inference II (3)
School of Criminal Justice
CRJ 681 Statistical Techniques in Criminal Justice Research
CRJ 687 Statistical Techniques in Criminal Justice Research II (4)
Department of Educational and Counseling Psychology and Statistics
(School of Education)
PSY 530 Statistical Methods I (3)
PSY 630 Statistical Methods II (3)
Department of Sociology
(College of Arts and Sciences)
SOC 522 Intermediate Statistics for Sociologists (3)
SOC 622 Advanced Statistics for Sociologists (3)
Students may meet the statistics requirement through completion of two equivalent courses at another university and may apply up to six credits for these courses to the 36 required for the degree. The courses must be approved in advance by the Chair of the Ph.D. Program.
Advanced Data Analysis
The two-semester sequence in statistics provides doctoral
students with a strong foundation in statistics. To
build on this foundation and to provide students with
greater depth in data analysis that is relevant to their
scholarly research, students are required to complete
a third course in data analysis methods. This third
data analysis course must be in advanced data analysis,
covering topics not covered in the required statistics
course sequence or covering topics in greater depth.
Examples of appropriate courses include those on regression,
structural equation modeling, and non-parametric statistics
as well as those addressing data analysis techniques
for qualitative methods such as narrative analysis,
ethnography, case studies, and focus groups. This course
must be approved by the student's advisor. (Requirement
effective Fall 2005.)
Advanced Research Course
The two proseminars in research provide doctoral students
with a strong foundation in research methodology. To
build on this foundation and to provide students with
greater depth in research methods that are relevant
to their scholarly research, students are required to
complete a third research course. This third research
course must be on a specific research topic or methodology
that is not covered or not covered in depth in SSW 862
(Social Welfare Research) and SSW 863 (Application of
Advanced Methods). Examples of appropriate courses include
those in qualitative research, survey research, and
epidemiology. This course must be approved by the student's
advisor. (Requirement effective Fall 2005.)
Language or Computer Proficiency
Students must also show proficiency in computer skills or a foreign language. These requirements may be demonstrated in any of the following four ways:
1) Successful completion of courses SSW 679 and SSW 687
Students will usually complete this requirement by taking the above courses, which also meet the student's statistics requirement. Learning a standard computer program and practice in its application has been built into these courses
2) Approved Computer Course
Students satisfactorily complete (B or better) a course approved by the Ph.D. Program Committee that requires the student to become proficient in the use of a social science statistical package on the computer. In accordance with University regulations, credit for this course cannot be counted toward the 36 credits required for graduation. In addition, the following regular University courses have been approved:
EPI 514 Computer Programming and Data Management (3)
CPY 720 Computer Applications in Counseling Psychology (3)
3) Performance Examination on Computer Skills
After receiving a set of raw data, students show they are able to put these data into the computer and are able to write and run a series of statistical procedures using a social science statistical package.
4) Oral Examination on Computer Skills
The examination is based on a sample of the student's
computer work. The student explains procedures used
and answers questions relating to these procedures.
5) Certification in a Foreign Language
Students must submit a letter signed by an official of a foreign language department of an accredited university certifying that the student has reading facility in the language.
Students may take as electives any graduate course offered within the School or elsewhere in the University that is relevant to the student's program of study (that does not repeat previous course work) with the approval of their adviser. An elective may also be taken at another university.
Internships, in which students advance knowledge and skill through application, can be arranged in such areas as teaching, research, management, and direct practice. In teaching internships, students work with faculty members, usually in relation to one of the faulty member's courses. Supervised classroom instruction is normally included as part of the internship. In research internships students may participate in research conducted by a faculty member or in agency-based research. In agency-based internships students must have an agency supervisor in addition to a supervising faculty member.
Students may do an internship at their place of employment (if other than the University at Albany) and be paid for their work by their employers, providing that the internship: 1) enables students to enhance their research knowledge or skill, and 2) involves activities that are not part of their regular jobs.
Students may apply two three-credit internships toward the 36 credits required for graduation. Tasks and responsibilities for which students are being financially compensated by the University at Albany may not be used as a significant part of an internship.
Courses Outside the School
Students are encouraged to enroll in substantive courses outside the School to achieve specific learning objectives and to acquire new perspectives that bear upon their developing knowledge of social work and social welfare. A minimum of six credit hours (exclusive of the required statistics courses) must be taken outside the School. Students whose master's degree is in a field other than social work are not required to take courses outside the School of Social Welfare. Students may receive credit for any graduate course in the University for which they have received prior approval from their adviser. Of the 36 credits of graduate study required beyond the master's degree, no more than three credits may be earned at another University. (An exception is made for statistics courses, see Statistics.) Applicants to the doctoral program must request transfer of credit at the doctoral level earned at another university as part of their application. Students already enrolled in the program must obtain prior approval to take a course at another university. The standard transfer of credit form should be used for this purpose.
The qualifying examinations covers subjects defined generally by the content of the required proseminars and are intended to measure the students' mastery of that content. Examination questions are drawn from a reading list compiled from the proseminar bibliographies. The examinations normally take place the Thursdays and Friday of the week preceding the Fall semester and Thursday and Friday of the first week of the Spring semester. Students wishing to take an examination should notify the Ph.D. Program assistant at least one month in advance. Examinations are given in each of the following subjects: 1) Social Policy; 2) Research; and 3) Social Work Practice. Examinations are graded pass/fail. Students must pass all three examinations.
Predissertation Research Requirement
School of Social Welfare has added a predissertation research requirement for all Ph.D. students, effective with the Spring 02 entering class. The requirement will be met by production of a paper that includes a research problem, study plan, analysis and a report of the findings. This paper must be approved as meeting the requirement by the student's advisor.
Doctoral students need research experience in order to complete high quality dissertations. In the current program students may or may not get this experience, depending on whether they have a fellowship or assistantship that allows them to work in a mentored role with faculty, whether they are able to devote full-time to their studies, and whether their student experience allows them to be involved in a research project from start to finish (often a one-year assistantship does not provide this complete experience). The predissertation research requirement will give the student research experience and will provide an opportunity to conduct independent research. This requirement will help focus the student's individualized study, will result in higher quality dissertations, and will give the student publication possibility.
This requirement will be applied flexibly in conjunction with the student's research assistantships or fellowships, research practica, or course work in SSW or another department (proseminar, applied research, data analysis courses, or independent studies). To fulfill the requirement must be enrolled in or have completed a required research course, although it may be advantageous for most students to complete both research and statistics course requirements before undertaking the predissertation requirement.
It is highly desirable for the student to use the requirement in a way that will advance their dissertation research. Examples of acceptable projects include: 1) pilot study for the dissertation (e.g., measurement development, piloting research methods), 2) secondary analysis of existing data set, or 3) work with a faculty member on an aspect of the faculty's research (may be funded by the faculty member's project.)This requirement will focus the student's work while fulfilling course and other program requirements. The study is not a duplication of the essay or the dissertation. The student will prepare a report that is 10-15 pages long. The paper need not be published.
The requirement may be waived by the advisor if the student can present evidence that he or she has met the essentials of the requirement through prior research experience and writing. A note detailing reasons for the waiver should be placed in the student's folder.
The following competencies are to be used both for the evaluation of student projects completed while in the program as well as for granting waivers for students who have met the requirement prior to entering the program. The competencies can be met through either quantitative and qualitative studies. However, it is recognized that the predissertation project is a pilot research study and that the competencies must be seen in that light.
Not all projects will enable the student to demonstrate all competencies. For example, competencies 4 and 5 may not be relevant to a project making use of existing data. Generally the student will be able to meet the requirement through a demonstration of at least 5 of the competencies, which should include competencies 6 and 7.
To conceptualize a research problem and to operationalize it in the form of specific questions or hypotheses.
- To develop a research design to answer the questions or test the hypotheses posed in the research problem.
- To develop and implement a sampling plan.
- To develop or select instruments appropriate to the research problem.
To use the instruments developed or selected to collect data.
- To analyze the data collected to satisfactorily address the research problem.
- To report the results in a coherent fashion with attention to limitations of the study.
The doctoral essay, a 20-25 page paper, is intended to serve three main purposes: 1) to further the student's potential for scholarly work, 2) to move students along in the development of a dissertation topic, and 3) to enable the student to complete a review of the literature relevant to his or her topic. The essay or portions of it can be incorporated into the student's proposal and dissertation.
Students should exhibit a mastery of knowledge in their selected area, and the paper should reflect a high level of integrative and conceptual ability. While publication is not a requirement, the essay should be of publishable quality. The essay should conclude with questions for further study. Ideally the questions should include those to be addressed in the dissertation.
Students submit a brief prospectus stating the purpose and scope of the essay for review and approval by their Doctoral Committee, usually after successfully completing the qualifying examination. Once the prospectus has been approved, students have 15 weeks to complete the essay. In completing the essay, the student is encouraged to consult with his or her chair or submit a draft of the essay to the chair or other committee members for their reactions.
The essay is graded satisfactory/unsatisfactory by members of the committee and must receive a grade of satisfactory from each member to be considered acceptable. At its discretion, the Doctoral Committee may meet (with or without the student) to discuss the essay before reaching a final decision about its acceptability. If an essay is found to be unsatisfactory, the student in consultation with the committee will develop a plan for the completion of the essay within a specified time period.
Admission to Candidacy
Admission to candidacy requires that in addition to the general University requirements students have met the following requirements:
- Satisfactory record in course and seminar study;
- Satisfactory completion of the language or computer proficiency;
- Satisfactory completion of the predissertation research requirement;
- Satisfactory completion of the qualifying examinations;
- Satisfactory completion of the doctoral essay;
Once admitted to candidacy, students need to take only one dissertation credit to maintain continous registration.
The dissertation advances the knowledge base of social work practice or the field of social welfare. Students are encouraged to begin to develop dissertation ideas and to do preliminary work on a potential dissertation topic during their first year of study.
The development of a formal dissertation proposal and the bulk of the student's dissertation research generally takes place at some point following successful completion of the qualifying examination.
A single Doctoral Committee will oversee both the writing of the essay and all subsequent work on the dissertation. The student's Doctoral Committee will consist of at least three members: a chair and one other faculty member from the School of Social Welfare and one member from outside the School. For oversight of the doctoral essay only, all members may be from within the School. Prior to the approval of the dissertation proposal, however, an outside member must join the Committee, either to replace one of the members from the school or as a fourth member. Outside members of the three-person Doctoral Committee may be from outside the University provided that they have an earned doctorate or hold the rank of full professor at an accredited University. Names of prospective committee members are proposed by the student to the Ph.D. Program Chair who appoints the Committee.
An individual without an earned doctorate or full professorship may serve as one member of the three-person committee if he or she possesses expert knowledge needed by the student that would not otherwise be available. The student must petition the Ph.D. Program Committee to have such an exception made.
To the extent possible, Doctoral Committee membership should remain constant. If changes in membership become necessary for a reason such as departure of a faculty member to another institution, the Ph.D. Chair will appoint a replacement suggested by the student. The chair of the Doctoral Committee may continue to serve as chair of the committee after leaving the university by mutual agreement of the faculty member and the student. If the Doctoral Committee chair must be off campus for an extended period (e.g. sabbatical leave abroad), arrangements should be made for an interim chair from among the Committee members.
Forming a Committee
The student normally begins to form a Doctoral Committee after successfully completing the Qualifying Examination. In setting up their Committees, students may want to consult with their Academic Adviser or the Program Chair in order to get ideas about which faculty members might serve on their on their Committees. (The Academic Adviser or the Program Chair themselves may, of course, be potential Committee members.) The student first obtains the agreement of a faculty member to serve as Chair of the Doctoral Committee. In consultation with the Doctoral Committee Chair, the student then selects the remaining members and obtains agreements from them to serve on the Committee. The Doctoral Committee Chair then becomes the student's Academic Adviser.
The three Committee members must normally be present, although an outside member living at a distance from the campus may participate by speaker phone. Two faculty members (nonvoting), from in or outside the school, may be added to the committee. Approval of the proposal will be by consensus.
Criteria of Approval of Dissertation Topics
In considering proposed dissertation topics, attention is given to the following three criteria:
- The dissertation topic must have significant implications for social work or social welfare and must address a problem that has not been satisfactorily resolved by existing knowledge. This criterion permits many different forms of contribution to knowledge, to theory, to improvements of practice, to research methodology, and to new syntheses or analyses of existing knowledge. This criterion prescribes no single type of investigation, methodology, or source material. It permits qualitative or quantitative studies. It permits use of library, field-simulated, or experimental approaches. Exemptions for topics not meeting this criterion may be granted by the Ph.D. Program Committee.
- If the collection of data for the dissertation requires agency cooperation, students should present evidence of commitment of agencies for access to data sources. If students propose a dissertation that is part of a larger project, they need to make clear how their study will constitute an independent research undertaking.
- Approval by the Doctoral Committee is contingent upon approval of the proposal by the University Institutional Review Board or other IRBs that may be relevant.
Students are responsible for securing necessary IRB clearance.
The proposal shall include statement of problem, research
questions or hypotheses, study rationale or justification,
literature review, description of methodology, subject
cooperation and human subjects issues, analysis plan,
potential applications, and relevance to social welfare.
The doctoral essay (or portions thereof) that may provide
a review of literature, elaboration of problems, etc.,
can be appended to the proposal. Students are responsible
for providing all committee members with copies of all
More specifically, students should outline clearly the method to be used in the investigation in relation to the concepts, variables, sampling, instrumentation, data collection, organization, processing and analysis of data, including statistical procedures when appropriate. The guiding analytic scheme should be made operational for the major steps of the research. This outline may be considerably modified, or an alternative developed, for some types of dissertations e.g., qualitative investigations and library studies.
Students will usually work primarily with the chair of the Doctoral Committee in conducting the research. Students are responsible for keeping the chair informed of progress being made or obstacles being encountered. The chair is responsible for being accessible to the candidate and arranging for ongoing evaluation of the candidate's work at those points of completion which in the chair's judgment, require evaluation. Serious objections should be raised and communicated to the candidate in the early stages of research, if possible.
Students may enroll for 1 dissertation credit per semester to maintain registration while working on the dissertation. To be eligible for dissertation credit, students must be admitted to candidacy
The organization and length of the dissertation report will vary depending on the nature of the research on which the dissertation is based. Below is a brief chapter outline for reports of quantitative research. This outline, which assumes a report in a range of 100-125 pages plus appendices, is offered as only on possible model.
- Statement of Problem. The problem
to which the study was addressed is set forth, usually
in the form of questions or hypotheses. The importance
of the problem to social welfare should be discussed,
but very briefly, if the problem is of obvious importance.
A review of prior work on the problem should be
presented, but limited to prior work of direct relevance
to the study problem. Work less directly relevant,
possibly excerpted from the doctoral essay, can
be included as an appendix.
- Method. In this chapter the plan
of the study is presented: the research design,
sampling plan, descriptions of data collection instruments,
etc. The actual instruments can be included as appendices.
- Findings. The results of the study
are presented, usually with minimal interpretation.
Key tables are incorporated into the text. Additional
tables may be appended. An alternative is to discuss
findings as they are presented. Chapter 4 can then
present a summary of the study and its conclusions.
- Discussion. The findings of the
study are interpreted. What conclusions can be drawn
from them? How do they add to existing knowledge?
What implications do they have for theory, practice,
and research relevant to social welfare? What are
The three Committee members must participate in the defense. Normally all Committee members must be present. However, the outside member may participate through a speaker phone if he or she resides outside the Capital District. (The student is responsible for arranging to have a speaker phone available and for the cost of the call.) The defense is open to other members of the University community. Although they will not participate in the examination, attendees may be invited to ask questions following the conclusion of the defense. Final approval and required revisions will be decided by consensus of the voting members. The Committee Chair is responsible for integrating the suggestions for revision made by all three Committee members and communicating these to the student. The Committee may choose either to review and approve the revisions or to delegate this responsibility to the Chair.
Guidelines for Defense
- Prior to the defense, all members of the Committee should read the student's complete dissertation draft and make whatever suggestions for revisions they think are needed. Members may or may not request to see the revisions prior to the defense. If revisions desired by a member other than the Chair are substantial, he or she should consult with the Chair prior to discussing them with the student. A member approves the draft, for purposes of the defense, when he or she is satisfied with revisions the student has made or has agreed to make. All members should agree that the draft is ready for defense.
Additional revisions may be requested as one outcome of the defense. These may include revisions that the student agreed to make prior to the defense but may not have satisfactorily made in the Committee's judgment or revision identified during the process of conducting the defense. For example, during the examination, the Committee may raise questions about the draft that may not have occurred to individual members when they gave their prior approval. However, it is expected that revisions will be minor in the usual case.
- Prior to the defense the student should prepare a memorandum inviting faculty and other doctoral students to attend. The memo should include the date, time, and place of the defense and should indicate that abstracts of the dissertation will be available in the Doctoral Program Office. The memo and abstract should be given to the Program Assistant at least on week prior to the defense.
Appointment and Monitoring
- The student is responsible for obtaining agreements from faculty members to serve on Ph.D. committees. The chairs of these committees send Agreement-to-serve forms to the Chair, Ph.D. Program Committee, for approval.
- The Chair of the Ph.D. Program Committee will be responsible for obtaining and safekeeping of documents showing completion of requirements or having appropriate completions recorded on the student's transcript, for processing the admission to candidacy forms, and for forwarding folders for degree clearance.
- Students are responsible for informing themselves of program requirements they have met or need to meet. The student will not be given reminders regarding requirements not completed.
Joint M.S.W./Ph.D. Program
The School offers a joint M.S.W./Ph.D. program, that enables students to obtain both degrees in approximately one less semester than would be required if the degrees were pursued independently. The student receives the M.S.W. and can complete the Ph.D. with an additional 24 hours of course work plus other requirements outlined for the Ph.D. program. Students can apply to both programs simultaneously or they may enter the Ph.D. program after acceptance into the M.S.W. program. Students must be accepted into the Ph.D. program no later than the semester prior to receiving the M.S.W. degree. Students currently enrolled in a joint program at the master's level, including advanced standing students, should consult with the Program Chair regarding their eligibility before applying. Requirements for the joint program are outlined below.
M.S.W./Ph.D. Joint Program -- 84 credits (minimum)
- 1. All students are expected to enroll in
the following required courses (46 credits):
- SSW 600 Social Welfare Policy and Services (3)
- SSW 610 Human Behavior and Social Environment I (3)
- SSW 611 Human Behavior and Social Environment II (3)
- SSW 620 Micro Practice in Social Work I (3)
- SSW 621 Micro Practice in Social Work II (3)
- SSW 630 Macro Practice in Social Work I (3)
- SSW 631 Macro Practice in Social Work II (3)
- SSW 650 Field Instruction I (3)
- SSW 651 Field Instruction II (4)
- SSW 823 Social Welfare Practice Theory (Proseminar) (3)
- SSW 826 Social Welfare Policy (Proseminar) (3)
- SSW 862 Social Welfare Research (Proseminar) (3)
- SSW 863 Application of Advanced Methods in Social Welfare Research (Proseminar) (3)
- Plus two courses in Statistics (6)
Exemption examinations may be taken for the courses SSW 600, 610, 611, and 660. Passing of these exams exempts the student from taking the course, but no credit is given. In place of the exempted course(s), electives must be taken to fulfill the required amount of credits. Exemption examinations are given prior to the start of the fall semester.
- 2a. Additional Required Courses for Students
in MACRO Concentration (20 credits):
- SSW 753 Field Instruction III (4)
SSW 754 Field Instruction IV (4)
SSW 790 Human Service Organizations in a Changing Environment (3)
SSW 791 Managing Systems in Human Services Organizations (3)
SSW 792 Community Building (3)
- One elective (3)
- 2b. Additional Required Courses for Students
in Direct Practice Concentration (20 credits):
- SSW 752 Field Instruction III (4)
SSW 753 Field Instruction IV (4)
One course designated as Advanced Behavior (3)
Two courses designated as Advanced Practice (6)
- Plus a minimum of 3 credits of elective graduate courses related to direct practice
- 3. You select your second-year concentration
(direct practice or MACRO) during your first year of
enrollment in the MSW Program.
- 4. Supporting and Elective Courses required
for all students are appropriate courses totaling at
least 18 graduate credits to complete the master's concentration
and to develop the doctoral social welfare problem and
practice intervention area of study.
- 5. Additionally, all students must:
- a. Have a satisfactory record in all course and seminar study;
b. Complete satisfactorily the research tool requirement;
c. Complete satisfactorily the qualifying examination;
- d. Complete satisfactorily the predissertation requirement;
e. Complete satisfactorily the doctoral essay;
- f. Submit an acceptable dissertation based on independent
- g. Complete at least two acceptable substantive courses
outside of the School of Social Welfare.
Guidelines for Outside Members of Doctoral Committees
Below are summarized some key points that doctoral committee members from outside our department might find helpful in working with our students. The rules relating to the doctoral essay and dissertation are appended below.
- Usually the student's initial step is to complete the Doctoral Essay, a review of the literature which will become part of the dissertation. The student will first circulate for the Committee's approval a prospectus for the essay. When that is approved the student will complete the essay and submit that to the Committee. Your responsibility is to review the prospectus and subsequently the essay. The Chair will advise you about whatever specific procedure he or she wishes to be used in the Committee's review of the essay and in providing feedback to the student.
- The student will then prepare a Dissertation Proposal, which will be circulated to the Committee. (The student may wish to consult with you prior to completing the proposal.) If you think the proposal needs further work, communicate your thoughts directly to the student. When the proposal seems to be reasonably satisfactory to each Committee member, a Proposal Defense is held. The main purposes of the defense are to provide additional guidance to the student and to grant formal approval of the proposal. Additional revisions may be required before approval is given. All Committee members participate. (This is usually the first meeting of the Committee as a whole).
- The student may or may not consult with you while carrying out the dissertation but should keep you informed of progress from time to time.
- As the dissertation nears completion the student should work out with you a plan for your review of the document -- e.g. whether chapter by chapter or as a whole. Indicate to the student what additional work you think might be needed to make the dissertation acceptable from you viewpoint. You do not need to communicate your ideas about revisions to the Chair, unless you think that there are major deficiencies in the student's work. When each Committee member thinks the dissertation is generally acceptable, the student is given permission to set up the Final Defense.
- All members participate in the Final Defense. Approval of the dissertation is by consensus. Approval may be contingent on further revisions in the dissertation.