The Quasi-Biennial Oscillation in atmospheric ozone

Examination of the relationship between tropical stratosphere zonal wind and ozone indicate a variable response in latitude with Northern Hemisphere tropics and polar regions and Southern Hemisphere mid-latitudes showing the strongest response with relatively weaker response at Northern Hemisphere mid-latitudes and the Southern Hemisphere tropics. In tropical regions, the west winds and ozone maxima are in phase while at higher latitudes, a more nearly out-of-phase relationship prevails. At subtropical and middle latitudes, the QBO in ozone does not appear to change phases with altitude. These features are suggestive of an interaction between the tropical zonal winds and poleward transport of horizontal eddies in conjunction with the annual poleward transport of ozone

The Power of the Pill for the Next Generation

In this paper we ask how the diffusion of oral contraception to young unmarried women affected the number and maternal characteristics of children born to these women. Using census data, we find that early pill access led to an increase in the share of children whose mothers were married, college-educated, and had professional occupations. The pill's effects on the average mother are different from the pill's effects on the average woman, and the effects of the pill on maternal characteristics are in some instances different from the effects of abortion. We investigate the mechanisms by which the pill led to these differential effects and find that access to the pill led to falls in short-term fertility rates for young women and led to decreases in lifetime fertility at the intensive and extensive margins. The impacts of the pill on household characteristics are thus associated with retiming of births, changes in the characteristics of potential mothers, changes in which women become mothers, and by reductions in completed family size. Finally, while the pill affected maternal characteristics differently than abortion, we find suggestive results that availability of the pill lowered abortions among young women.

Cost models in digital archiving : an overview of life cycle management at the National Library of the Netherlands

The number of institutions that are either considering the implementation of a digital archive or already started with an operational digital archive service is increasing. While technological and organisational challenges are well-studied and in few cases even welldefined, the subject of costs often remains untouched, which in many cases prevent organisations from new initiatives. In this paper two leading digital preservation techniques – migration and emulation - will be discussed in terms of life cycle management and associated cost models. Both techniques are studied and considered for implementation at the Koninklijke Bibliotheek, National Library of the Netherlands

Matched Thermistors for Microwave Power Meters-Patent

Matched thermistors for microwave power meters with compensation for temperature change

Legal deposit of digital materials

Results of scientific research are nowadays as a rule published digitally. It is almost inconceivable that any scientist would not present the results of his or her work in digital form, even if it is in parallel to a physical copy delivered by a publisher. This is certainly the case for Science, Technology and Medicine, the research fields that produce over 80% of all scientific publications. Traditionally academic libraries have contributed to the keeping of the output of science through time. For deposit libraries - mostly the national libraries - the maintenance of the Record of Science is even a key task. The maintenance of collections by libraries is under pressure as more publications turn digitally. One reason is the change of policy of publishers who preferably do no longer sell but rather license their publications, offering them through sophisticated search and retrieval services. Another reason is that handling and maintaining digital publications requires new skills and a different infrastructure than for printed publications. And complicating matters even further is the fact that great research and development efforts are required, as no best practices on the issues are yet available

Segregation and Black Political Efficacy

The impact of segregation on Black political efficacy is theoretically ambiguous. On one hand, increased contact among Blacks in more segregated areas may mean that Blacks are better able to coordinate political behavior. On the other hand, lesser contact with non-Blacks may mean that Blacks have less political influence over voters of other races. As for non-Blacks, inter-group conflict theory suggests that greater contact yields greater conflict between the groups while inter-group contact theory suggests exactly the reverse. We investigate this question empirically. We find that exogenous increases in segregation lead to decreases in Black civic efficacy, as measured by an ability to elect Representatives who vote liberally and more specifically in favor of legislation that is favored by Blacks. This tendency for Representatives from more segregated MSAs to vote more conservatively arises in spite of the fact that Blacks in more segregated areas hold more liberal political views than do Blacks in less segregated locales. We find evidence that this decrease in efficacy is driven by more conservative attitudes amongst non-Blacks in more segregated areas.

Mm-wave power meter mount

E-band thermistor mount and a technique for adjusting a temperature compensating thermistor to provide an electrically balanced bridge are used for measuring RF power in the mm-wavelength. The mount is relatively insensitive to temperature effects that cause measurement errors in single ended circuits

Cost Models in Digital Archiving

Intervention à la 33e conférence générale annuelle de la Ligue des bibliothèques européennes de recherche (Liber)

Abortion and Selection

The introduction of legalized abortion in the early 1970s led to dramatic changes in fertility behavior. Some research has suggested as well that there were important impacts on cohort outcomes, but this literature has been limited and controversial. In this paper, we provide a framework for understanding the mechanisms through which abortion access affects cohort outcomes, and use that framework to both address inconsistent past methodological approaches, and provide evidence on the long-run impact on cohort characteristics. Our results provide convincing evidence that abortion legalization altered young adult outcomes through selection. In particular, we find evidence that lower costs of abortion led to improved outcomes in the birth cohort in the form of an increased likelihood of college graduation, lower rates of welfare use, and lower odds of being a single parent. We also find that our empirical innovations do not substantially alter earlier results regarding the relationship between abortion and crime, although most of that relationship appears to reflect cohort size effects rather than selection.