222 research outputs found
Comment on Y. Couder and E. Fort: "Single-Particle Diffraction and Interference at a Macroscopic Scale", Phys. Rev. Lett. (2006)
In a paper from 2006, Couder and Fort [1] describe a version of the famous
double slit experiment performed with drops bouncing on a vibrated fluid
surface, where interference in the particle statistics is found even though it
is possible to determine unambiguously which slit the "walking" drop passes. It
is one of the first papers in an impressive series, showing that such walking
drops closely resemble de Broglie waves and can reproduce typical quantum
phenomena like tunneling and quantized states [2-13]. The double slit
experiment is, however, a more stringent test of quantum mechanics, because it
relies upon superposition and phase coherence. In the present comment we first
point out that the experimental data presented in [1] are not convincing, and
secondly we argue that it is not possible in general to capture quantum
mechanical results in a system, where the trajectory of the particle is
well-defined.Comment: 4 pages, 1 figur
From Burdens To Benefits: The Societal Impact Of PDL-Enriched, Efficacy-Enhanced Educators
Societies continue to absorb increased burdens in cost for helping citizens unable to achieve at optimal levels. Building on past research, we project educational benefits to offset current societal burdens through enhanced educator capabilities. Studies reviewed show participation in a high-impact professional development and learning solution resulted in improved student performance and reduced dropout rates, reduced disciplinary rates and increased rates for college-bound, along with lower teacher turnover. Computations show that generalization of such impacts should trade societal burdens for benefits at between 6.9 billion within the first year. Cumulatively within 20 years the burdens converted to benefits are projected to exceed $85 billion. Enhanced educator capabilities will substantively reduce needs and costs for societal programs, replaced with tangible benefits to all
Spin excitations and quantum criticality in the quasi-one-dimensional Ising-like ferromagnet CoCl2·2D2O in a transverse field
Individual Exposure to NO2 in Relation to Spatial and Temporal Exposure Indices in Stockholm, Sweden: The INDEX Study
Epidemiology studies of health effects from air pollution, as well as impact assessments, typically rely on ambient monitoring data or modelled residential levels. The relationship between these and personal exposure is not clear. To investigate personal exposure to NO2 and its relationship with other exposure metrics and time-activity patterns in a randomly selected sample of healthy working adults (20–59 years) living and working in Stockholm. Personal exposure to NO2 was measured with diffusive samplers in sample of 247 individuals. The 7-day average personal exposure was 14.3 µg/m3 and 12.5 µg/m3 for the study population and the inhabitants of Stockholm County, respectively. The personal exposure was significantly lower than the urban background level (20.3 µg/m3). In the univariate analyses the most influential determinants of individual exposure were long-term high-resolution dispersion-modelled levels of NO2 outdoors at home and work, and concurrent NO2 levels measured at a rural location, difference between those measured at an urban background and rural location and difference between those measured in busy street and at an urban background location, explaining 20, 16, 1, 2 and 4% (R2) of the 7-day personal NO2 variation, respectively. A regression model including these variables explained 38% of the variation in personal NO2 exposure. We found a small improvement by adding time-activity variables to the latter model (R2 = 0.44). The results adds credibility primarily to long-term epidemiology studies that utilise long-term indices of NO2 exposure at home or work, but also indicates that such studies may still suffer from exposure misclassification and dilution of any true effects. In contrast, urban background levels of NO2 are poorly related to individual exposure
Anbefaling på valg av standarder/rammeverk for velferdsteknologi
Velferdsteknologi kan gi mange, uansett alder, mulighet for å bo hjemme under trygge forhold dersom man blir syk, behøver omsorg eller bare ønsker mulighet til å bo hjemme i en sen fase i livet
Structural Alterations from Multiple Displacement Amplification of a Human Genome Revealed by Mate-Pair Sequencing
Comprehensive identification of the acquired mutations that cause common cancers will require genomic analyses of large sets of tumor samples. Typically, the tissue material available from tumor specimens is limited, which creates a demand for accurate template amplification. We therefore evaluated whether phi29-mediated whole genome amplification introduces false positive structural mutations by massive mate-pair sequencing of a normal human genome before and after such amplification. Multiple displacement amplification led to a decrease in clone coverage and an increase by two orders of magnitude in the prevalence of inversions, but did not increase the prevalence of translocations. While multiple strand displacement amplification may find uses in translocation analyses, it is likely that alternative amplification strategies need to be developed to meet the demands of cancer genomics
Long term effects of micro-surgical testicular sperm extraction on androgen status in patients with non obstructive azoospermia
BACKGROUND: The aim of our study was to review the results of microsurgically performed testicular sperm extraction (TESE) and to evaluate its possible long term effects on serum testosterone (T). METHODS: We operated on 48 men (35 +/- 8 years) with non-obstructive azoospermia (NOA). If no spermatozoa were found following a micro epididymal sperm extraction (Silber et al., 1994) and testicular biopsy, testicular microdissection was performed or multiple microsurgical testicular biopsies were taken. The mean follow-up of the serum T was 2.4 +/- 1.1 years. RESULTS: Sperm was retrieved in 17/48 (35%) of the men. The per couple take home baby rate if sperm was retrieved was 4/17 (24%). Serum T decreased significantly at follow-up (p < 0.05) and 5/31 (16%) de novo androgen deficiencies developed CONCLUSION: In patients with non-obstructive azoospermia in whom no spermatozoa were found following a micro epididymal sperm aspiration and a simple testicular biopsy, we were able to retrieve spermatozoa in 35% of the men. The take home baby rate was 24% among couples with spermatozoa present upon TESE. De novo androgen deficiency occurred in 16% of the male patients following TESE indicating that, in men with NOA, long term hormonal follow up is recommended after TESE
Long-term particulate matter exposure and mortality: a review of European epidemiological studies
<p>Abstract</p> <p>Background</p> <p>Several studies considered the relation between long-term exposure to particulate matter (PM) and total mortality, as well as mortality from cardiovascular and respiratory diseases. Our aim was to provide a comprehensive review of European epidemiological studies on the issue.</p> <p>Methods</p> <p>We searched the Medline database for epidemiological studies on air pollution and health outcomes published between January 2002 and December 2007. We also examined the reference lists of individual papers and reviews. Two independent reviewers classified the studies according to type of air pollutant, duration of exposure and health outcome considered. Among European investigations that examined long-term PM exposure we found 4 cohort studies (considering total and cardiopulmonary mortality), 1 case-control study (considering mortality from myocardial infarction), and 4 ecologic studies (2 studies considering total and cardiopulmonary mortality and 2 studies focused on cardiovascular mortality).</p> <p>Results</p> <p>Measurement indicators of PM exposure used in European studies, including PM10, PM2.5, total suspended particulate and black smoke, were heterogeneous. This notwithstanding, in all analytic studies total mortality was directly associated with long-term exposure to PM. The excesses in mortality were mainly due to cardiovascular and respiratory causes. Three out of 4 ecologic studies found significant direct associations between PM indexes and mortality.</p> <p>Conclusion</p> <p>European studies on long-term exposure to PM indicate a direct association with mortality, particularly from cardiovascular and respiratory diseases.</p
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