Review: A Private Universe online resources

A Private Universe depicts a very familiar situation for teachers worldwide, namely that students do not let go of their misconceptions as easily as might be expected after a detailed and thorough learning process

Is space really expanding? A counterexample

In all Friedman models, the cosmological redshift is widely interpreted as a consequence of the general-relativistic phenomenon of EXPANSION OF SPACE. Other commonly believed consequences of this phenomenon are superluminal recession velocities of distant galaxies and the distance to the particle horizon greater than c*t (where t is the age of the Universe), in apparent conflict with special relativity. Here, we study a particular Friedman model: empty universe. This model exhibits both cosmological redshift, superluminal velocities and infinite distance to the horizon. However, we show that the cosmological redshift is there simply a relativistic Doppler shift. Moreover, apparently superluminal velocities and `acausal' distance to the horizon are in fact a direct consequence of special-relativistic phenomenon of time dilation, as well as of the adopted definition of distance in cosmology. There is no conflict with special relativity, whatsoever. In particular, INERTIAL recession velocities are subluminal. Since in the real Universe, sufficiently distant galaxies recede with relativistic velocities, these special-relativistic effects must be at least partly responsible for the cosmological redshift and the aforementioned `superluminalities', commonly attributed to the expansion of space. Let us finish with a question resembling a Buddhism-Zen `koan': in an empty universe, what is expanding?Comment: 12 pages, no figures; added Appendix with a calculation of the cosmological redshift in `private space

Characteristics of Private Schools in the United States: Results From the 2011-12 Private School Universe Survey

In 1988, the National Center for Education Statistics (NCES) developed a private school data collection that improved on the sporadic collection of private school data dating back to 1890 bydeveloping an alternative to commercially available private school sampling frames. Since 1989, the U.S. Bureau of the Census has conducted the biennial Private School Universe Survey (PSS) for NCES. The PSS is designed to generate biennial data on the total number of private schools, students, and teachers, and to build a universe of private schools to serve as a sampling frame of private schools for NCES sample surveys. For more information about the methodology and design of the PSS, please see the Technical Notes in appendix B of this report. The target population for the PSS is all schools in the 50 states and the District of Columbia that are not supported primarily by public funds, provide classroom instruction for one or more of grades kindergarten through 12 (or comparable ungraded levels), and have one or more teachers. Organizations or institutions that provide support for home schooling, but do not provide classroom instruction, are not included. The 2011 -- 12 PSS data were collected between September 2011 and May 2012. All data are for the 2011 -- 12 school year except the high school graduate data, which are for the 2010 -- 11 school year.Because the purpose of this report is to introduce new NCES survey data through the presentation of tables containing descriptive information, only selected findings are listed below. These findings are purely descriptive in nature and are not meant to imply causality. These findings have been chosen to demonstrate the range of information available from the 2011 -- 12 PSS rather than to discuss all of the observed differences, emphasize any particular issue, or make comparisons over time.The tables in this report contain counts and percentages demonstrating bivariate relationships. All of the results have been weighted to reflect the sample design and to account for nonresponse and other adjustments. Comparisons drawn in the selected findings have been tested for statistical significance at the .05 level using Student's t statistics to ensure that the differences are larger than those that might be expected due to sampling variation. No adjustments were made for multiple comparisons. Many of the variables examined are related to one another, and complex interactions and relationships have not been explored. Statistical Analysis Software (SAS 9.2) and SUDAAN (10.0) were used to compute the statistics for this report

Distributed Private Heavy Hitters

In this paper, we give efficient algorithms and lower bounds for solving the heavy hitters problem while preserving differential privacy in the fully distributed local model. In this model, there are n parties, each of which possesses a single element from a universe of size N. The heavy hitters problem is to find the identity of the most common element shared amongst the n parties. In the local model, there is no trusted database administrator, and so the algorithm must interact with each of the $n$ parties separately, using a differentially private protocol. We give tight information-theoretic upper and lower bounds on the accuracy to which this problem can be solved in the local model (giving a separation between the local model and the more common centralized model of privacy), as well as computationally efficient algorithms even in the case where the data universe N may be exponentially large

Typology of Public-Private Equity

Private equity, which pools funds for investment in private businesses, is one of the largest and fastest growing investment opportunities in the markets today. Private equity traditionally sought investments exclusively from sophisticated investors such as high net worth individuals and institutional investors. More recently, however, a growing number of private equity businesses have gone public and opened their doors to public investors, who are drawn to these investments because of the possibility of high returns and the opportunity to diversify their investment portfolios. In this Article, I review the universe of public-private equity (or PPE) businesses that are traded on the United States stock exchanges to map out how PPE has engaged with public investors. I find that PPE takes a variety of organizational forms, across different jurisdictions, and seeks investments from public investors at multiple levels within the private equity structure. While this variety expands the menu of options available to public investors, ignoring the fact that there are distinct types within the PPE universe can also be the source of investor and regulatory confusion. In this Article, I organize the PPE universe into three types according to whether the public investor is investing in the private equity adviser, fund, or both. This typology catalogs a complex and heterogeneous universe of firms that are sometimes lumped together as one to provide a deeper understanding of the unique structural and governance features of each type of PPE. And, by taking a segmented view of the company, fund, and securities regulatory regimes which apply, this Article takes the first step towards constructing a clear framework through which to understand and regulate PPE

Irrelevant externality angst.

Due to the high transaction cost that would be necessary for large numbers of people to negotiate with each other, even those who are usually sanguine about private markets become reserved when externalities affect large populations. The distinction between private and societal interest is well understood for pecuniary externalities, but neglect of Buchanan and Stubblebine’s article Externality has left the same distinction widely unrecognized for non-pecuniary ones. If only a few parties on either side experience a relevant externality private interactions can appropriately internalize costs and benefits across the entire population. Regardless of the perceptiveness of legal and cultural institutions in placing entitlements, and regardless of the level of transaction cost among the universe of the affected, a surprising number of externalities will readily fix themselves. The desirability of corrective intervention is much too easily conceded.

U.S.-Based Private Voluntary Organizations: Religious and Secular PVOs Engaged in International Relief & Development

We have constructed a new and substantial data set from 1939 to 2004 on U.S.-based private voluntary organizations (PVOs) engaged in international relief and development. The universe comprises PVOs registered with the federal government (U.S. Agency for International Development since the early 1960s). PVOs are classified by type among secular and 14 types of religious categories. Classifications were made for the date of founding and in 2004 (or last date of existence). We can therefore examine shifts in classification over time%u2014among religion types and between religious and secular. The data set has information on revenue and expenditure for each year. We distinguish revenue by source: federal, international organization, and private. We distinguish within these sources by grants, contracts, in-kind and cash donations, and so on. We break down expenditure into categories, including a division between international and domestic programs. This data set allows us to track trends in the overall universe of PVOs and by type of PVO in terms of numbers registered, income, expenditure, and sub-categories of income and expenditure. Analysis can now be conducted at the individual agency and aggregate levels for PVOs engaged in international relief and development and registered with the U.S. federal government from 1939 to 2004.

Still a Private Universe? Community College Students’ Understanding of Evolution

Background Measuring what students know and retain about evolution is essential to improving our understanding of how students learn evolution. The literature shows that college students appear to have a poor understanding of evolution, answering questions on various instruments correctly only about half of the time. There is little research regarding evolution understanding among community college students and so this study examines if those students who are enrolled in life science classes, who are assessed using questions based on grade eight standards, show a better understanding of evolutionary principles than younger students and if there are differences in knowledge based on course enrollment. The authors utilized a survey of 41 items of the Life Sciences Concept Inventory that were specifically designed to measure knowledge about various aspects of evolution that relate to the 5–8 grade science standards on evolution. They administered it to 191 adult students who were enrolled in nine sections across five life sciences courses at one community college in Southern California. Results Results indicated that the students in this study possessed a fair understanding of evolution, averaging scores of nearly 70%, higher than what other researchers have found (using different instruments). Students enrolled in biology major classes scored significantly higher than those enrolled in non/mixed-major courses. There was a strong relationship between item difficulty and discrimination as well as difficulty and misconception strength. When compared with the 5–8 grade student data, the community college students showed a lower level of difficulty and higher levels of item discrimination, but the proportion choosing the most popular wrong answer (the dominant misconception), was comparable. College students showed similar patterns to the grade 5–8 students in terms of which questions and which material were the most challenging, despite performing better overall. Conclusions In this study, students possessed fair understanding of evolution. However, they were assessed with an instrument designed for 5th through 8th grade students. The results of this study support the need for more research into how community college students understand evolution and which factors impact that understanding