On Bootstrap Coverage Probability with Dependent Data

This paper establishes the optimal bootstrap block lengths for coverage probabilities when the bootstrap is applied to covariance stationary ergodic dependent data. It is shown that the block lengths that minimize the error in coverage probabilities of one- and two-sided block bootstrap confidence intervals of normalized and studentized smooth functions of sample averages are proportional to $n^{1/4}$. The minimum error rates in coverage probabilities of one- and two-sided block bootstrap confidence intervals are of order O($n^{-3/2}$) and O($n^{-5/4}$), respectively, for normalized and studentized statistics. This constitutes a refinement over the asymptotic confidence intervals.

Density and current response functions in strongly disordered electron systems: Diffusion, electrical conductivity and Einstein relation

We study consequences of gauge invariance and charge conservation of an electron gas in a strong random potential perturbed by a weak electromagnetic field. We use quantum equations of motion and Ward identities for one- and two-particle averaged Green functions to establish exact relations between density and current response functions. In particular we find precise conditions under which we can extract the current-current correlation function from the density-density correlation function and vice versa. We use these results in two different ways to extend validity of a formula associating the density response function with the electrical conductivity from semiclassical equilibrium to quantum nonequilibrium systems. Finally we introduce quantum diffusion via a response relating the current with the negative gradient of the charge density. With the aid of this response function we derive a quantum version of the Einstein relation and prove the existence of the diffusion pole in the zero-temperature electron-hole correlation function with the the long-range spatial fluctuations controlled by the static diffusion constant.Comment: 16 pages, REVTeX4, 6 EPS figure

Internet Sex Crimes Against Minors: The Response of Law Enforcement.

The Internet1 and computers have come to play a growing role in sex crimes that are committed against children and youth.2 Since the mid-1990s these developing technologies have posed challenges for law enforcement requiring them to confront situations not anticipated in criminal statutes, master technical advances, develop new investigative techniques, and handle criminal cases that often span multiple jurisdictions. To assist, legislators have acted on a number of fronts creating new statutes that encompass Internet offenses, stiffening penalties, and creating a national clearinghouse for reports of Internet-related crimes against children and the CyberTipline® operated by the National Center for Missing & Exploited Children. In addition the federal government has increased funding in this area creating Internet Crimes Against Children Task Forces to support state and local law enforcement and specialized Internet, child-exploitation units in federal, law-enforcement agencies. Unfortunately the results of these initiatives are difficult to track. Criminaljustice authorities do not collect information specifically about Internet-related crimes. The National Juvenile Online Victimization (N-JOV) Study was undertaken to get a sense of the scope and types of law-enforcement activity in this area and serve as a baseline for monitoring the growth of Internet sex crimes against minors and related law-enforcement activities

Sex trafficking cases involving minors.

This bulletin summarizes findings from the National Juvenile Prostitution Study (N‐JPS). It describes the prevalence and types of sex trafficking cases that ended in arrests or detentions by U.S. law enforcement agencies in 2005 and explores the characteristics of youth involved in sex trafficking, the characteristics of the cases themselves, and how police view these juveniles—as victims or as delinquents. The bulletin also covers policy and practice implica‐ tions and recommends several next steps for advancing the handling of these cases. Some findings include the fol‐ lowing: • There were an estimated 1,450 arrests and detentions for sex trafficking crimes involving youth in the United States in 2005. • Sex trafficking cases involving minors fell into three groups: (1) Third‐party exploiter cases, (2) Solo juvenile cases, and (3) Child sexual abuse cases involving payment. • Police treated 69% of juveniles as victims and 31% as delinquents. • Findings indicate a strong relationship between a case originating with an outside report to police and the juvenile being treated as a victim

National Juvenile Online Victimization Study (N-JOV): Methodology Report.

The National Juvenile Online Victimization Study (N-JOV Study) was conducted by the Crimes against Children Research Center at the University of New Hampshire, under grants from the National Center for Missing & Exploited Children and the Office of Juvenile Justice and Delinquency Prevention, U.S. Department of Justice. The N-JOV study collected information from a national sample of law enforcement agencies about the characteristics of Internet sex crimes against minors and the numbers of arrests for these crimes during a one-year period. The goals of our methodology were to 1) design a representative national sample of law enforcement agencies that would give us an overall picture of these crimes in the U.S., 2) understand how these cases emerged and were handled in a diverse group of agencies, and 3) get detailed data about the characteristics of these crimes from well-informed, reliable sources. We used a two-phase process to collect data from a national sample of local, county, state and federal law enforcement agencies. In Phase 1, we sent a mail survey to a national sample of law enforcement agencies asking if they had made arrests in Internet-related child pornography or sexual exploitation cases between July 1, 2000 and June 30, 2001. In Phase 2, we conducted telephone interviews with law enforcement investigators about a sample of the cases reported in the mail survey. The final data set, weighted to account for sampling procedures and other factors, includes data from 612 completed interviews

Trends in Law Enforcement Responses toTechnology‐facilitated Child Sexual Exploitation Crimes: TheThird National Juvenile OnlineVictimization Study (NJOV‐3)

Abstract Overall arrests for technology‐facilitated child sexual exploita‐ tion crimes did not continue to increase from 2006 to 2009 as they had earlier in the decade. However, arrests for child por‐ nography possession increased by about 50% from 2006 to 2009. In addition, arrests for technology‐facilitated sex crimes with identified victims doubled, but the increase was in cases where offenders knew their victims in person, not cases in which they met online. Arrests of offenders who solicited undercover police posing as minors declined between 2006 and 2009, after rising earlier in the decade. The decline may be because of shifts in law enforcement strategies that included more focus on child pornography offenses

Highlights of the Youth Internet Safety Survey.

This fact sheet reports on the findings of the Youth Internet Safety Survey, which collected information about incidents of possible online victimization of youth