Length sensing and control for Einstein Telescope Low Frequency

In this paper we describe a feasible length sensing and control scheme for the low frequency interferometers of the Einstein Telescope (ET-LF) along with the techniques used to optimise several optical parameters, including the length of the recycling cavities and the modulation frequencies, using two numerical interferometer simulation packages: Optickle and Finesse. The investigations have suggested the use of certain combinations of sidebands to obtain independent information about the different degrees of freedom

A new type of quantum speed meter interferometer: measuring speed to search for intermediate mass black holes

The recent discovery of gravitational waves (GW) by LIGO has impressively launched the novel field of gravitational astronomy and it allowed us to glimpse at exciting objects we could so far only speculate about. Further sensitivity improvements at the low frequency end of the detection band of future GW observatories rely on quantum non-demolition (QND) methods to suppress fundamental quantum fluctuations of the light fields used to readout the GW signal. Here we invent a novel concept of how to turn a conventional Michelson interferometer into a QND speed meter interferometer with coherently suppressed quantum back-action noise by using two orthogonal polarisations of light and an optical circulator to couple them. We carry out a detailed analysis of how imperfections and optical loss influence the achievable sensitivity and find that the configuration proposed here would significantly enhance the low frequency sensitivity and increase the observable event rate of binary black hole coalescences in the range of $10^2-10^3 M_\odot$ by a factor of up to $\sim300$.Comment: 8 pages, 5 figures. Modified figures and text in v

Genome-wide identification and characterisation of human DNA replication origins by initiation site sequencing (ini-seq).

Next-generation sequencing has enabled the genome-wide identification of human DNA replication origins. However, different approaches to mapping replication origins, namely (i) sequencing isolated small nascent DNA strands (SNS-seq); (ii) sequencing replication bubbles (bubble-seq) and (iii) sequencing Okazaki fragments (OK-seq), show only limited concordance. To address this controversy, we describe here an independent high-resolution origin mapping technique that we call initiation site sequencing (ini-seq). In this approach, newly replicated DNA is directly labelled with digoxigenin-dUTP near the sites of its initiation in a cell-free system. The labelled DNA is then immunoprecipitated and genomic locations are determined by DNA sequencing. Using this technique we identify >25,000 discrete origin sites at sub-kilobase resolution on the human genome, with high concordance between biological replicates. Most activated origins identified by ini-seq are found at transcriptional start sites and contain G-quadruplex (G4) motifs. They tend to cluster in early-replicating domains, providing a correlation between early replication timing and local density of activated origins. Origins identified by ini-seq show highest concordance with sites identified by SNS-seq, followed by OK-seq and bubble-seq. Furthermore, germline origins identified by positive nucleotide distribution skew jumps overlap with origins identified by ini-seq and OK-seq more frequently and more specifically than do sites identified by either SNS-seq or bubble-seq.Francis Crick Institute, which receives its core funding from Cancer Research UK [FC001-157]; Medical Research Council [FC001-157]; Wellcome Trust [FC001-157]; National Institute for Health Research; Biotechnology and Biological Sciences Research Council [BB/K013378/1]This is the final version of the article. It first appeared from Oxford University Press via http://dx.doi.org/10.1093/nar/gkw76

Umkämpfte Globalisierung: Amerikanische und europäische Reaktionen auf Chinas Aufstieg im Hochtechnologiebereich

Der Aufstieg Chinas hat zu einer Reihe von Konflikten mit den führenden westlichen Ländern geführt. Der Hintergrund dieser Auseinandersetzungen besteht darin, dass chinesische Konzerne zu ernsthaften Konkurrenten US-amerikanischer und europäischer Unternehmen geworden sind und die Ordnungsvorstellungen von US- und EU-Machteliten auf der einen und jene Chinas auf der anderen Seite auseinanderdriften. Denn in China sind politische und wirtschaftliche Macht anders organisiert als in den westlichen Marktwirtschaften: Der Parteistaat ist (Teil‑)Eigentümer wichtiger Unternehmen und interveniert offen mit Fünfjahresplänen in die Volkswirtschaft. Die Kommunistische Partei Chinas ist als Regulationsinstanz in Unternehmen präsent. Gleichzeitig organisiert der Parteistaat seine Herrschaft durch Output-Legitimität und funktioniert vielerorts als kennziffergesteuertes, meritokratisches System. Die Expansion des hybriden chinesischen Parteistaatskapitalismus führt deshalb zu einem neuen Systemkonflikt: Wirtschaftlich werden aufstrebende chinesische (Staats‑)Unternehmen zu Konkurrenten, politisch wird die Kontrolle von sensiblen Datenströmen und Infrastrukturnetzwerken zum Streitpunkt. In dem Artikel werden aktuelle Konfliktdynamiken zwischen den USA und China einerseits und der EU und China andererseits in den Bereichen Außenhandel, Investitionen, Hochtechnologie und Industriepolitik aus der Perspektive der Vergleichenden Politischen Ökonomie und des Weltsystemansatzes untersucht. Es werden jeweils Unterschiede in den Reaktionen herausgearbeitet: Die USA setzten auf eine aggressive Handels- und Sanktionspolitik, während die EU mit defensiveren Maßnahmen reagiert hat. Es wird gezeigt, wie diese Konflikte Chinas staatsgetriebene Globalisierungsstrategie verändern und zur Restrukturierung der Weltwirtschaft beitragen.The rise of China has led to a series of conflicts with the leading Western countries. The reasons for these disputes are that Chinese corporations have become serious competitors for US and European companies and that there are diverging approaches of governing the market between Western and Chinese power elites. In China, political and economic power are organized differently than in the US and the EU. The party-state is the (partial) owner of important companies and openly intervenes in the national economy by five-year plans. Furthermore, the Communist Party of China is engaged in companies as a regulatory authority. At the same time, the party-state organizes its rule through output legitimacy and functions in many respects as an indicator-driven, meritocratic system. The expansion of hybrid Chinese party-state capitalism is therefore leading to a new system conflict. Economically, emerging Chinese (state-owned) enterprises are becoming competitors. Politically, the control of sensitive data flows and infrastructure networks is resulting in contention. The article analyzes current conflict dynamics between the US resp. the EU and China in the areas of foreign trade, investment, high technology, and industrial policy. Comparative political economy and world-system analysis guide the analysis. In each case, there are differences in the policy responses: The US has relied on aggressive trade and sanctions policies, while the EU has reacted more defensively. It is shown how these conflicts could change China's state-driven globalization strategy and contribute to the restructuring of the world economy

Local-Oscillator Noise Coupling in Balanced Homodyne Readout for Advanced Gravitational Wave Detectors

The second generation of interferometric gravitational wave detectors are quickly approaching their design sensitivity. For the first time these detectors will become limited by quantum back-action noise. Several back-action evasion techniques have been proposed to further increase the detector sensitivity. Since most proposals rely on a flexible readout of the full amplitude- and phase-quadrature space of the output light field, balanced homodyne detection is generally expected to replace the currently used DC readout. Up to now, little investigation has been undertaken into how balanced homodyne detection can be successfully transferred from its ubiquitous application in table-top quantum optics experiments to large-scale interferometers with suspended optics. Here we derive implementation requirements with respect to local oscillator noise couplings and highlight potential issues with the example of the Glasgow Sagnac Speed Meter experiment, as well as for a future upgrade to the Advanced LIGO detectors.Comment: 7 pages, 5 figure

'There and Back Again'-Forward Genetics and Reverse Phenotyping in Pulmonary Arterial Hypertension.

Although the invention of right heart catheterisation in the 1950s enabled accurate clinical diagnosis of pulmonary arterial hypertension (PAH), it was not until 2000 when the landmark discovery of the causative role of bone morphogenetic protein receptor type II (BMPR2) mutations shed new light on the pathogenesis of PAH. Since then several genes have been discovered, which now account for around 25% of cases with the clinical diagnosis of idiopathic PAH. Despite the ongoing efforts, in the majority of patients the cause of the disease remains elusive, a phenomenon often referred to as "missing heritability". In this review, we discuss research approaches to uncover the genetic architecture of PAH starting with forward phenotyping, which in a research setting should focus on stable intermediate phenotypes, forward and reverse genetics, and finally reverse phenotyping. We then discuss potential sources of "missing heritability" and how functional genomics and multi-omics methods are employed to tackle this problem

Demonstration of a switchable damping system to allow low-noise operation of high-Q low-mass suspension systems

Low mass suspension systems with high-Q pendulum stages are used to enable quantum radiation pressure noise limited experiments. Utilising multiple pendulum stages with vertical blade springs and materials with high quality factors provides attenuation of seismic and thermal noise, however damping of these high-Q pendulum systems in multiple degrees of freedom is essential for practical implementation. Viscous damping such as eddy-current damping can be employed but introduces displacement noise from force noise due to thermal fluctuations in the damping system. In this paper we demonstrate a passive damping system with adjustable damping strength as a solution for this problem that can be used for low mass suspension systems without adding additional displacement noise in science mode. We show a reduction of the damping factor by a factor of 8 on a test suspension and provide a general optimisation for this system.Comment: 5 pages, 5 figure

Effects of static and dynamic higher-order optical modes in balanced homodyne readout for future gravitational waves detectors

With the recent detection of Gravitational waves (GW), marking the start of the new field of GW astronomy, the push for building more sensitive laser-interferometric gravitational wave detectors (GWD) has never been stronger. Balanced homodyne detection (BHD) allows for a quantum noise (QN) limited readout of arbitrary light field quadratures, and has therefore been suggested as a vital building block for upgrades to Advanced LIGO and third generation observatories. In terms of the practical implementation of BHD, we develop a full framework for analyzing the static optical high order modes (HOMs) occurring in the BHD paths related to the misalignment or mode matching at the input and output ports of the laser interferometer. We find the effects of HOMs on the quantum noise limited sensitivity is independent of the actual interferometer configuration, e.g. Michelson and Sagnac interferometers are effected in the same way. We show that misalignment of the output ports of the interferometer (output misalignment) only effects the high frequency part of the quantum noise limited sensitivity (detection noise). However, at low frequencies, HOMs reduce the interferometer response and the radiation pressure noise (back action noise) by the same amount and hence the quantum noise limited sensitivity is not negatively effected in that frequency range. We show that the misalignment of laser into the interferometer (input misalignment) produces the same effect as output misalignment and additionally decreases the power inside the interferometer. We also analyze dynamic HOM effects, such as beam jitter created by the suspended mirrors of the BHD. Our analyses can be directly applied to any BHD implementation in a future GWD. Moreover, we apply our analytical techniques to the example of the speed meter proof of concept experiment under construction in Glasgow. We find that for our experimental parameters, the performance of our seismic isolation system in the BHD paths is compatible with the design sensitivity of the experiment

A pilot study to examine association of BMI with functional class and six minute walk distance in idiopathic and heritable PAH : possible association with estrogen metabolism

Abstract: The hypothesis that a relationship exists between body mass index (BMI), functional class, and 6 min walk distance (6MWD) in Group 1‐pulmonary arterial hypertension (PAH) was examined. Analysis of data from the UK National Cohort Study for heritable pulmonary arterial/idiopathic PAH suggests increased BMI is a predictor of worse functional class and shorter 6MWD; increased body‐weight in mice and man may be associated with increased estrogen metabolism