Can the states of the W-class be suitable for teleportation

Entangled states of the W-class are considered as a quantum channel for teleportation or the states to be sent. The protocols have been found by unitary transformation of the schemes, based on the multiuser GHZ channel. The main feature of the W-quantum channels is a set of non-local operators, that allow receivers recovering unknown state.Comment: 4 pages, revtex4, no figure

On preparation of the W-states from atomic ensembles

A scheme, where three atomic ensembles can be prepared in the states of the W-class via Raman type interaction of strong classical field and a projection measurement involved three single-photon detectors and two beamsplitters, are considered. The obtained atomic entanglement consists of the Dicke or W-states of each of the ensembles.Comment: 4 pages, 1 figure, minor correction

Did Household Consumption Become More Volatile?

We show that volatility of household consumption, after accounting for predictable variation arising from movements in real interest rates, preferences and income shocks, increased between 1970 and 2002. For single parent households, and households headed by nonwhite or poorly educated individuals, this rise was signi¯cantly larger. This stands in sharp contrast with the dramatic fall in aggregate volatility of the US economy, and may have significant welfare implications. A spectacular fall in average covariances of consumption growth rates across households over this period accounts for the diverging paths of aggregate and household level volatilities.consumption risk, volatility decomposition, aggregate volatility, panel data.

Russia (2008): HIV/AIDS TRaC Study of Risk, Health-seeking Behaviors, and Their Determinants, Among Men Who Have Sex with Men in Eight Regions of the Russian Federation. Second Round.

Description of Intervention: PSI's LaSky program targeting MSM combines the distribution of informational and motivational materials to the target group with outreach activities, "edutainment" group sessions and inter-personal communications delivered by trained peer educators and opinion leaders. LaSky also supports an internet site with information, and a counseling telephone hotline.Methodology: The baseline survey in 2006 used time-location sampling; due to low response rates the follow-up in 2008 used respondent-driven sampling (RDS). Sample size was calculated for all the regions together. The baseline was a single-stage cluster sample, with locations where MSM congregate defined as clusters. The number of respondents to be selected was proportionate to cluster size. In every region the estimates of the number of MSM per cluster were calculated as a part of mapping exercise conducted prior to data collection. The follow-up in 2008 used the clusters defined in 2006 to select seeds (initial respondents). In large metropolitan centers (where the estimated number of total MSM in more than 20,000) four recruitment waves were completed. In smaller locations the estimated number of MSM is below 10,000, and three recruitment waves were completed. A total of 539 and 1113 interviews respectively were completed for the baseline and follow-up studies. Analyses consisted of logistic regression and anovas to examine trends over time, to ascertain which determinants are correlated with key behaviors, and to examine the association between program exposure and changes in health behaviors and determinants. Socio-demographic characteristics and geographic location were controlled for in the analyses.Main FindingsThe monitoring table highlights that:The share of respondents who report having relationships with a permanent partner has reached 82.0%, up from 68.3% two years ago (p value less than .001). Yet the number of respondents reporting having casual partners has also increased (p value less than .05), which suggests that MSM tend to maintain multiple sexual relationships at any given time.Condom use is far from being universal and varies by type of partner. In 2008, condom use at last sex with casual partners was 66.8%, and it was only 44.1% with permanent partners. The findings show a significant improvement in condom use among casual partners over time, but no change in condom use with permanent partners.The results of segmentation analysis indicate that the probability of MSM using condom during last contact with male partner increases with availability of free condoms. Almost 85% of those practicing safe sex report having received condoms for free, the respective figure for non-users is 77% (p value less than .01). Thus, the availability of free condoms encourages MSM to use condoms.Self-efficacy to discuss condom use. MSM who are confident in their ability to discuss condom use with different types of partners are more likely to use condoms at last sex with a male partner. The respective means are 2.86 for users and 2.58 for non-users (p value less than .001).Perception of condoms making sex less pleasant. Predictably, respondents who disagree with the statement "condoms make sex less pleasant" are more likely to use condoms than those who subscribe to this notion (45% vs. 30.2%, respectively, p value less than .001).The results of evaluation analysis reveal that PSI program exposure is associated with:An increase in condom use with casual partners as well as commercial partners (p value less than .05).A greater likelihood of being tested for STIs (p value less than .05).Increased confidence to negotiate condom use with different types of partners, being better informed about the requirement for HIV test being accompanied by pre-and post-test counseling, and knowing that it is not possible to tell by looking if a person has an STI (p value less than .05).A higher perception of being at risk for HIV (p value less than .05).There was no effect on the perception that condoms make sex less pleasant

"Evolution of Consumption Volatility for the Liquidity Constrained Households over 1983 to 2004"

We study whether the increased income uncertainty in the US over the last quarter-century had a negative impact on household welfare by looking at variability of household consumption growth. We are particularly interested in understanding the effect of greater uncertainty on the liquidity constrained households. We study the evolution of liquidity constraints in the US in the Panel Study of Income Dynamics, extending Jappelli et al. [1998] methodology using information from the Survey of Consumer Finances. We find that although household indebtedness increased substantially, reflecting greater availability of credit, there was no decline in the proportion of liquidity constrained households between 1983 and 2007. Applying methodology developed in Gorbachev [2009], we find that the evolution of consumption volatility for the liquidity constrained households increased by economically and statistically more than for the unconstrained households. This increase was lower than that of family income volatility for these groups. Nevertheless, the welfare cost to society is substantial: we estimate that an average household would be willing to sacrifice 4.7 percent of nondurable consumption per year to lower consumption risk to its 1984 levels.panel data, Euler estimation, racial divide, uncertainty, credit