Analytic Examples, Measurement Models and Classical Limit of Quantum Backflow

We investigate the backflow effect in elementary quantum mechanics - the phenomenon in which a state consisting entirely of positive momenta may have negative current and the probability flows in the opposite direction to the momentum. We compute the current and flux for states consisting of superpositions of gaussian wave packets. These are experimentally realizable but the amount of backflow is small. Inspired by the numerical results of Penz et al (M.Penz, G.Gr\"ubl, S.Kreidl and P.Wagner, J.Phys. A39, 423 (2006)), we find two non-trivial wave functions whose current at any time may be computed analytically and which have periods of significant backflow, in one case with a backwards flux equal to about 70 percent of the maximum possible backflow, a dimensionless number $c_{bm} \approx 0.04$, discovered by Bracken and Melloy (A.J.Bracken and G.F.Melloy, J.Phys. A27, 2197 (1994)). This number has the unusual property of being independent of $\hbar$ (and also of all other parameters of the model), despite corresponding to an obviously quantum-mechanical effect, and we shed some light on this surprising property by considering the classical limit of backflow. We discuss some specific measurement models in which backflow may be identified in certain measurable probabilities.Comment: 33 pages, 14 figures. Minor revisions. Published versio

Rapid, single-tube method for quantitative preparation and analysis of RNA and DNA in samples as small as one cell

BACKGROUND: Current methods for accurate quantification of nucleic acids typically begin with a template preparation step in which DNA and/or RNA are freed of bound proteins and are then purified. Isolation of RNA is particularly challenging because this molecule is sensitive to elevated temperatures and is degraded by RNases, which therefore have to be immediately inactivated upon cell lysis. Many protocols for nucleic acids purification, reverse transcription of RNA and/or amplification of DNA require repeated transfers from tube to tube and other manipulations during which materials may be lost. RESULTS: This paper introduces a novel and highly reliable single-tube method for rapid cell lysis, followed by quantitative preparation and analysis of both RNA and/or DNA molecules in small samples. In contrast to previous approaches, this procedure allows all steps to be carried out by sequential dilution in a single tube, without chemical extraction or binding to a matrix. We demonstrate the utility of this method by quantification of four genes, Xist, Sry and the two heat-inducible hsp70i (hsp70.1 and hsp70.3), as well as their RNA transcripts in single mouse embryos and in isolated blastomeres. CONCLUSION: This method virtually eliminates losses of nucleic acids and is sensitive and accurate down to single molecules

Adsorption of CO on Supported Gold Nanoparticle Catalysts: A Comparative Study

The adsorption of CO on three different gold nanoparticle catalysts supported on high surface area TiO2 was studied using infrared transmission spectroscopy at room temperature and CO pressures typically used in CO oxidation reactions. The three, real-world catalysts were Au catalysts synthesized in our laboratory from thiol monolayer protected clusters (MPCs) and two commercial catalysts from the World Gold Council (WGC and AuTEK). Within experimental reproducibility, the adsorption data for the three catalysts are indistinguishable. While showing approximately Langmuir behavior, the adsorption data also show coverage dependence, as others have observed for many catalyst systems. Two approaches were used to fit the data, a two-site model and a variable binding constant model. The two-site Langmuir model yielded strong (36%) and weak (64%) binding constants of 2740 and 146 atm-1, respectively. Alternatively, using a sliding-tangent Langmuir fit gave a variable binding constant of 2670-120 atm-1 at room temperature for coverage θ ) 0-0.8. The heat of adsorption was then extracted from the binding constants using a literature value for -TΔS. These values were determined as ΔH)-64 and -56 kJ/mol for strong and weak binding according to the two-site model and ΔH)-63 to -56 kJ/mol for coverage θ ) 0-0.8 for the variable binding constant model. These values agree well with literature values obtained (i) using supported catalysts under higher pressures and (ii) using model catalysts under higher pressures and ultrahigh vacuum conditions

The Late Quaternary geology of the Housatonic River basin in southwestern Massachusetts and adjacent Connecticut

Guidebook for field trips in western Massachusetts, northern Connecticut and adjacent areas of New York: 67th annual meeting October 10, 11, and 12, 1975: Trip B-7; C-

North American Indigenous Adolescent Substance Use

Objectives—To investigate growth in problem drinking and monthly marijuana use among North American Indigenous adolescents from the upper Midwest and Canada. Methods—Panel data from a community-based participatory research project includes responses from 619 adolescents residing on or near 7 different reservations/reserves. All respondents were members of the same Indigenous cultural group. Results—Rates of problem drinking and monthly marijuana use increased steadily across the adolescent years, with fastest growth occurring in early adolescence (before age 15). In general, female participants reported higher rates of substance use prior to age 15; however, male reports of use surpassed those of females in later adolescence. Conclusions—Results of this study highlight the importance of early adolescent substance use prevention efforts and the possible utility of gender responsive programming

Sedimentation in a proglacial lake: Glacial Lake Hitchcock

Guidebook for field trips in Connecticut and south central Massachusetts: New England Intercollegiate Geological Conference 74th annual meeting, University of Connecticut, Storrs Connecticut , October 2 and 3, 1982: Trip Q-

Correlates of bullying behaviors among a sample of North American Indigenous adolescents

The purpose of this study was to examine the relationship between familial, educational, and psychosocial factors and bullying among 702 North American Indigenous adolescents aged 11–14 years. The study used multinomial logistic regression models to differentiate correlates of bully perpetration and victimization versus being neither and between being a perpetrator versus being a victim. Analyses reveal that being a bully victim had different correlates than being a perpetrator. Perceived discrimination was associated with increased odds of being either a victim or a perpetrator, relative to being neither. Several factors differentiated being a bully perpetrator from being a bully victim: adolescent age, parental warmth and support, depressive symptoms, anger, and school adjustment. These findings expand upon the limited understanding of the factors associated with bullying among North American Indigenous youth. Bullying intervention and prevention programs that target Indigenous adolescents should be culturally grounded and begin early within the family

Factors associated with growth in daily smoking among Indigenous adolescents

North American Indigenous adolescents smoke earlier, smoke more, and are more likely to become regular smokers as adults than youth from any other ethnic group, yet we know very little about their early smoking trajectories. We use multilevel growth modeling across five waves of data from Indigenous adolescents (aged 10-13 years at Wave 1) to investigate factors associated with becoming a daily smoker. Several factors, including number of peers who smoked at Wave 1 and meeting diagnostic criteria for major depressive episode and conduct disorder, were associated with early daily smoking. Only age and increases in the number of smoking peers were associated with increased odds of becoming a daily smoker. © 2012 The Authors. Journal of Research on Adolescence © 2012 Society for Research on Adolescence

Correlates of Homeless Episodes among Indigenous People

This study reports the correlates of homeless episodes among 873 Indigenous adults who are part of an ongoing longitudinal study on four reservations in the Northern Midwest and four Canadian First Nation reserves. Descriptive analyses depict differences between those who have and have not experienced an episode of homelessness in their lifetimes. Multivariate analyses assess factors associated with a history of homeless episodes at the time of their first interview. Results show that individuals with a history of homeless episodes had significantly more individual and family health, mental health, and substance abuse problems. Periods of homelessness also were associated with financial problems. Among the female caretakers who experienced episodes of homelessness over the course of the study, the majority had been homeless at least once prior to the start of the study and approximately one–fifth met criteria for lifetime alcohol dependence, drug abuse, or major depression. Family adversity during childhood was also common for women experiencing homelessness during the study