Quantum correlations across two octaves from combined up and down conversion

We propose and analyse a cascaded optical parametric system which involves three interacting modes across two octaves of frequency difference. Our system, combining degenerate optical parametric oscillation (OPO) with second harmonic generation (SHG), promises to be a useful source of squeezed and entangled light at three differing frequencies. We show how changes in damping rates and the ratio of the two concurrent nonlinearities affect the quantum correlations in the output fields. We analyse the threshold behaviour, showing how the normal OPO threshold is changed by the addition of the SHG interactions. We also find that the inclusion of the OPO interaction removes the self-pulsing behaviour found in normal SHG. Finally, we show how the Einstein-Podolsky-Rosen correlations can be controlled by the injection of a coherent seed field at the lower frequency.Comment: 23 pages, 11 figures, theor

Effects of post-abortion family planning services on contraceptive practices in China : protocol for a clustered randomized controlled trial

Study objectives: To determine whether integrating post-abortion services in hospital settings in China will increase the contraceptive use and decrease repeat abortion rates. Study design: Three-arms cluster randomised controlled trial in which the unit of randomisation is hospital. Participants: Women seeking induced abortion within 12 weeks of gestation age. Sites: Ninety hospitals from 30 provinces in China will be randomised to the three arms of the study stratified by province. In each province, eligible hospitals will be matched on the characteristics of abortion departments, especially the volume of abortions in the 2 months in the situation survey. Length of follow up: Six months. Intervention: Multiple interventions that aim to increase the use of more effective contraceptive methods, improve user adherence to reduce the unintended pregnancies and repeat induced abortions. Data collection: Data will be collected at four time points, one at baseline(month 0 at the time of enrolment) and twice during intervention (1st 3rd and 6th month after enrolment, respectively). Primary outcome: Unintended pregnancies or repeated induced abortions; immediate contraceptive uptake and the use of modern effective contraceptive methods

On exponential densities and limit ratios of subsets of N

Funding: National Natural Science Foundation of China (11671189,11971109).Given α,β,γ∈[0,1] with α≤β, we prove that there exists a subset of N such that its lower and upper exponential densities and its lower and upper limit ratios are equal to α, β, γ and 1, respectively. This result provides an affirmative answer to an open problem posed by Grekos et al. (Unif Distrib Theory 6:117–130, 2011).Publisher PDFPeer reviewe

3D-Matched-Filter Galaxy Cluster Finder I: Selection Functions and CFHTLS Deep Clusters

We present an optimised galaxy cluster finder, 3D-Matched-Filter (3D-MF), which utilises galaxy cluster radial profiles, luminosity functions and redshift information to detect galaxy clusters in optical surveys. This method is an improvement over other matched-filter methods, most notably through implementing redshift slicing of the data to significantly reduce line-of-sight projections and related false positives. We apply our method to the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) Deep fields, finding ~170 galaxy clusters per square degree in the 0.2 <= z <= 1.0 redshift range. Future surveys such as LSST and JDEM can exploit 3D-MF's automated methodology to produce complete and reliable galaxy cluster catalogues. We determine the reliability and accuracy of the statistical approach of our method through a thorough analysis of mock data from the Millennium Simulation. We detect clusters with 100% completeness for M_200 >= 3.0x10^(14)M_sun, 88% completeness for M_200 >= 1.0x10^(14)M_sun, and 72% completeness well into the 10^(13)M_sun cluster mass range. We show a 36% multiple detection rate for cluster masses >= 1.5x10^(13)M_sun and a 16% false detection rate for galaxy clusters >~ 5x10^(13)M_sun, reporting that for clusters with masses <~ 5x10^(13)M_sun false detections may increase up to ~24%. Utilising these selection functions we conclude that our galaxy cluster catalogue is the most complete CFHTLS Deep cluster catalogue to date.Comment: 18 pages, 17 figures, 5 tables; v2: added Fig 5, minor edits to match version published in MNRA

Functional analysis of human alpha 1(I) procollagen gene promoter. Differential activity in collagen-producing and -nonproducing cells and response to transforming growth factor beta 1.

To gain a further understanding of the regulation of human type I collagen gene expression under physiologic and pathologic conditions, we characterized 5.3 kilobase pairs (kb) of the human alpha 1(I) procollagen gene promoter. A series of deletion constructs containing portions of the alpha 1(I) procollagen 5\u27-flanking region (with end points from -5.3 kb to -84 base pairs (bp)) ligated to the chloramphenicol acetyltransferase (CAT) reporter gene were transiently transfected into NIH/3T3 cells. Maximal CAT activity was observed with constructs having 5\u27 end points from -804 to -174 bp. A further 5\u27 deletion to -84 bp caused a marked reduction in CAT activity. Cells transfected with plasmids containing longer 5\u27-flanking fragments of the alpha 1(I) procollagen gene (-2.3 or -5.3 kb) showed reduced CAT activity compared with the -804 bp construct. The activity of the alpha 1(I) procollagen promoter was much lower in cells that do not normally express type I collagen (HeLa cells) compared with collagen-producing NIH/3T3 cells. The CAT activity of deletion constructs containing longer 5\u27 regions than -84 bp was increased by approximately 2-fold in NIH/3T3 cells treated with transforming growth factor beta 1 (TGF beta 1). Electrophoretic mobility shift assays indicated that protein-DNA complex formation with a probe corresponding to the -170 to -80 bp fragment of the alpha 1(I) procollagen promoter was markedly enhanced in nuclear extracts prepared from TGF beta 1-treated fibroblasts as compared with untreated fibroblasts. The DNA binding activity stimulated by TGF beta 1 was specific for an Sp1-like sequence at positions -164 to -142 bp in the promoter. These results demonstrate that 1) there are both positive and negative cis-acting regulatory elements in the human alpha 1(I) procollagen promoter, 2) these regulatory regions function differently in collagen-producing and -nonproducing cells, 3) the alpha 1(I) procollagen promoter contains TGF beta 1-responsive sequences located between -174 and -84 bp from the transcription start site, and 4) TGF beta 1 caused marked stimulation of the DNA binding activity of a nuclear factor interacting with an Sp1-like binding site located within a region encompassing -164 to -142 bp of the alpha 1(I) procollagen promoter

What\u27s in The Bag?

As the bioprocessing industry continues to shift towards single-use systems, there is an increasing need for polymers with improved functionality. This article includes a review of the chemistry and functionality of various polymeric families, and a description of various tools that can be useful. Polyethylene resins are largely used in a variety of single use applications. This paper describes polyethylene chemistry in more detail so that single use system manufacturers and biopharmaceuticals manufacturers can optimize the use of polyethylene polymers in a particular application. The process in which the families of polyethylene polymer resins are manufactured dictates the degree of crystallinity, chain branching of the polymer, and migratory species. These molecular properties determine the physical properties (e.g. strength, flexibility, transparency, etc.) and the processability of the polymer in melt extrusion. The type of polymer can also determine the need for antioxidants and other processing additives which can affect the extractable profile of the contact layer. In addition to polyethylene resins, other polymeric families are known in the industry for providing specific functions such as barrier to moisture or gases, and adhesion. Polyamides, adhesive resins, and EVOH are very well known in the food packaging industry. Extending experience and leveraging tools from food packaging can benefit those who participate in the single use bioprocessing arena. Modeling tools can be used to optimize film structures, relative to cost, thickness, and performance, while minimizing the need for producing numerous test samples. Understanding the properties of the various polymer families allows for the design of the ideal solution for the targeted application(s)

Open charm scenarios

We discuss possibilities of identifying open charm effects in direct production processes, and propose that direct evidence for the open charm effects can be found in $e^+ e^-\to J/\psi\pi^0$. A unique feature with this process is that the $D\bar{D^*}+c.c.$ open channel is located in a relatively isolated energy, i.e. $\sim 3.876$ GeV, which is sufficiently far away from the known charmonia $\psi(3770)$ and $\psi(4040)$. Due to the dominance of the isospin-0 component at the charmonium energy region, an enhanced model-independent cusp effect between the thresholds of $D^0\bar{D^{*0}}+c.c.$ and $D^+ D^{*-}+c.c.$ can be highlighted. An energy scan over this energy region in the $e^+e^-$ annihilation reaction can help us to understand the nature of X(3900) recently observed by Belle Collaboration in $e^+ e^-\to D\bar{D}+c.c.$, and establish the open charm effects as an important non-perturbative mechanism in the charmonium energy region.Comment: 6 pages, Proceeding contribution to the Rutherford Centennial Conference, Aug. 8-12, 2011, Manchester, U.

Attention-deficit/ hyperactivity disorder in the offspring following prenatal maternal bereavement: a nationwide follow-up study in Denmark

Severe prenatal stress exposure has been found to increase the risk of neuropsychiatric conditions like schizophrenia. We examined the risk of attention-deficit/hyperactivity disorder (ADHD) in the offspring following prenatal maternal bereavement, as a potential source of stress exposure. We conducted a nationwide population-based cohort study including all 1,015,912 singletons born in Denmark from 1987 to 2001. A total of 29,094 children were born to women who lost a close relative during pregnancy or up to 1 year before pregnancy. These children were included in the exposed cohort and other children were in the unexposed cohort. We used Cox regression to estimate hazard ratios for ADHD, defined as the first-time ADHD hospitalization or first-time ADHD medication after 3 years of age. Boys born to mothers who were bereaved by unexpected death of a child or a spouse, had a 72% increased risk of ADHD [hazard ratio (HR) 1.72, 95% confidence interval (CI) 1.09–2.73]. Boys born to mothers who lost a child or a spouse during 0–6 months before pregnancy and during pregnancy had a HR of 1.47 (95% CI 1.00–2.16) and 2.10 (95% CI 1.16–3.80), respectively. Our findings suggest that prenatal maternal exposure to severe stress may increase the risk of ADHD in the offspring