The Myth of Superiority of American Encryption Products

Encryption software and hardware use sophisticated mathematical algorithms to encipher a message so that only the intended recipient may read it. Fearing that criminals and terrorists will use encryption to evade authorities, the United States now restricts the export of encryption products with key lengths of more than 56 bits. The controls are futile, because strong encryption products are readily available overseas. Foreign-made encryption products are as good as, or better than, U.S.-made products. U.S. cryptographers have no monopoly on the mathematical knowledge and methods used to create strong encryption. Powerful encryption symmetric-key technologies developed in other countries include IDEA and GOST. Researchers in New Zealand have developed very strong public-key encryption systems. As patents on strong algorithms of U.S. origin expire, researchers in other countries will gain additional opportunities to develop strong encryption technology based on those algorithms

Biogeochemical ecology of six species of Sphagnum in Costa Rica

There is very little information on the biogeochemical ecology of Sphagnum species in tropical regions. The majority of the ecological information on Sphagnum species in the tropics consists of general habitat information and pH values that are reported in new species descriptions and regional floras such as those of Crum (1980, 1989), Crum and Buck (1988), Karlin (1991), and McQueen (1989)

Welfare to Work in the U.S.: A Model for Other Nations?

The 1996 welfare reform legislation establishing the Temporary Assistance for Needy Families (TANF) program marks a significant change in U.S. social and economic policy. This legislation represents the ascendance of the view that individuals and families need to be self-reliant and that collective support for individual well-being should be minimized. We first describe the major provisions of TANF, providing some background on its differences from prior policy targeted at needy families. Then we catalogue the wide variety of economic changes that are implicit in the new law, stressing those related to changed property rights, fiscal relations among jurisdictions, and economic incentives facing families. Third, we illustrate the form of state reforms that are likely to develop in response to the federal policy change by describing the actions of the state of Wisconsin, which has taken the lead in implementing the new policy. We conclude with a list of yet unanswered questions that will ultimately determine just how far this policy change will slide the nation along the efficiency-equity tradeoff function, away from the equity axis. The answer to these questions will influence the attraction the U.S. reform might hold as a model for other nations concerned with their own safety net programs for poor people.

Nonmarket outcomes of schooling

Most studies of the benefits of education focus on market outcomes, particularly labor market returns. But the rewards of education are not limited to success at finding a job and earning money; schooling also affects nonmarket outcomes, such as one's health and the cognitive development of one's children. The authors discuss several nonmarket outcomes of education that have been confirmed by researchers and estimate the value that an additional year of schooling has on some of those outcomes.

The Intergenerational Effects of Early Childbearing

Since World War II, the average age at which women experience their first birth has drifted up, but since 1986 there has been a resurgence of births to teenagers. Just as early fertility appears to adversely affect the life chances of the teen mother, it may also have negative effects on her children. We hypothesize that when the children of teen mothers are young adults, they will tend to have lower education, and will be more likely to be economically inactive, to have children when they are teens, and to have children out of wedlock when they are teens. In this paper, we present several models designed to reveal the impact that being born to a teenage mother has on children's chances for success as young adults. Our findings indicate that the children of mothers who first gave birth as teens are adversely affected as young adults.

The X-ray line and continuum emission from a solar active region

The X-ray spectrum of the quiet sun in the energy range 2.3 - 6.9 keV was observed from an Aerobee rocket using an uncollimated graphite crystal spectrometer. These results and spatial measurements made with an onboard modulation collimator are analyzed using solar models

Uncoupling of p97 ATPase activity has a dominant negative effect on protein extraction

p97 is a highly abundant, homohexameric AAA+ ATPase that performs a variety of essential cellular functions. Characterized as a ubiquitin-selective chaperone, p97 recognizes proteins conjugated to K48-linked polyubiquitin chains and promotes their removal from chromatin and other molecular complexes. Changes in p97 expression or activity are associated with the development of cancer and several related neurodegenerative disorders. Although pathogenic p97 mutations cluster in and around p97's ATPase domains, mutant proteins display normal or elevated ATPase activity. Here, we show that one of the most common p97 mutations (R155C) retains ATPase activity, but is functionally defective. p97-R155C can be recruited to ubiquitinated substrates on chromatin, but is unable to promote substrate removal. As a result, p97-R155C acts as a dominant negative, blocking protein extraction by a similar mechanism to that observed when p97's ATPase activity is inhibited or inactivated. However, unlike ATPase-deficient proteins, p97-R155C consumes excess ATP, which can hinder high-energy processes. Together, our results shed new insight into how pathogenic mutations in p97 alter its cellular function, with implications for understanding the etiology and treatment of p97-associated diseases

Time Use and Population Representation in the Sloan Study of Adolescents

Do studies of time use interfere too much in the lives of the subjects? As a result are those who agree to participate a biased sample of the population? We examine the characteristics of the Experience Sampling Method (ESM) adolescent sample from the Alfred P. Sloan Study of Youth and Social Development in order to detect and quantify instances of sampling and nonresponse bias. According to available proxies for time use and standard demographic variables, the Sloan ESM sample is nearly representative in terms of teen employment rates, parental employment rates, a student's grade point average, and TV watching. Work hours are slightly undercounted in the study because of slightly higher nonresponse rates by teenagers working long hours. The sample is less representative in terms of the time of week and gender; nonresponse is relatively common on school nights and (to a lesser extent) on weekends, and among boys. We offer some suggestions regarding general implications of our findings for the measurement of time use.