Interferometric gravitational-wave detectors are complex instruments comprised of a Michelson interferometer enhanced by multiple coupled cavities. Active feedback control is required to operate ...these instruments and keep the cavities locked on resonance. The optical response is highly nonlinear until a good operating point is reached. The linear operating range is between and 1% of a fringe for each degree of freedom. The resonance lock has to be achieved in all five degrees of freedom simultaneously, making the acquisition difficult. Furthermore, the cavity linewidth seen by the laser is only Hz, which is four orders of magnitude smaller than the linewidth of the free running laser. The arm length stabilization system is a new technique used for arm cavity locking in Advanced LIGO. Together with a modulation technique utilizing third harmonics to lock the central Michelson interferometer, the Advanced LIGO detector has been successfully locked and brought to an operating point where detecting gravitational-waves becomes feasible.
Squeezed states of light are an important tool for optical measurements below the shot noise limit and for optical realizations of quantum information systems. Recently, squeezed vacuum states were ...deployed to enhance the shot noise limited performance of gravitational wave detectors. In most practical implementations of squeezing enhancement, relative fluctuations between the squeezed quadrature angle and the measured quadrature (sometimes called squeezing angle jitter or phase noise) are one limit to the noise reduction that can be achieved. We present calculations of several effects that lead to quadrature fluctuations, and use these estimates to account for the observed quadrature fluctuations in a LIGO gravitational wave detector. We discuss the implications of this work for quantum enhanced advanced detectors and even more sensitive third generation detectors.
Bridged or caged polycyclic hydrocarbons have rigid structures that project substituents into precise regions of 3D space, making them attractive as linking groups in materials science and as ...building blocks for medicinal chemistry. The efficient synthesis of new or underexplored classes of such compounds is, therefore, an important objective. Herein, we describe the silver(I)-catalyzed rearrangement of 1,4-disubstituted cubanes to cuneanes, which are strained hydrocarbons that have not received much attention since they were first described in 1970. The synthesis of 2,6-disubstituted or 1,3-disubstituted cuneanes can be achieved with high regioselectivities, with the regioselectivity being dependent on the electronic character of the cubane substituents. A preliminary assessment of cuneanes as scaffolds for medicinal chemistry suggests cuneanes could serve as isosteric replacements of trans-1,4-disubstituted cyclohexanes and 1,3-disubstituted benzenes. An analogue of the anticancer drug sonidegib was synthesized, in which the 1,2,3-trisubstituted benzene was replaced with a 1,3-disubstituted cuneane.
Squeezed states of light have been recently used to improve the sensitivity of laser-interferometric gravitational-wave detectors beyond the quantum limit. To completely establish quantum engineering ...as a realistic option for the next generation of detectors, it is crucial to study and quantify the noise coupling mechanisms which injection of squeezed states could potentially introduce. We present a direct measurement of the impact of backscattered light from a squeezed-light source deployed on one of the 4 km long detectors of the laser interferometric gravitational wave observatory (LIGO). We also show how our measurements inform the design of squeezed-light sources compatible with the even more sensitive advanced detectors currently under construction, such as Advanced LIGO.
Relative brain sizes in birds can rival those of primates, but large-scale patterns and drivers of avian brain evolution remain elusive. Here, we explore the evolution of the fundamental brain-body ...scaling relationship across the origin and evolution of birds. Using a comprehensive dataset sampling> 2,000 modern birds, fossil birds, and theropod dinosaurs, we infer patterns of brain-body co-variation in deep time. Our study confirms that no significant increase in relative brain size accompanied the trend toward miniaturization or evolution of flight during the theropod-bird transition. Critically, however, theropods and basal birds show weaker integration between brain size and body size, allowing for rapid changes in the brain-body relationship that set the stage for dramatic shifts in early crown birds. We infer that major shifts occurred rapidly in the aftermath of the Cretaceous-Paleogene mass extinction within Neoaves, in which multiple clades achieved higher relative brain sizes because of a reduction in body size. Parrots and corvids achieved the largest brains observed in birds via markedly different patterns. Parrots primarily reduced their body size, whereas corvids increased body and brain size simultaneously (with rates of brain size evolution outpacing rates of body size evolution). Collectively, these patterns suggest that an early adaptive radiation in brain size laid the foundation for subsequent selection and stabilization.
•Dinosaurs and early birds had similar relative brain sizes•Major shifts in brain-body integration occur in the aftermath of the K-Pg extinction•Rates of brain-body evolution are highest in non-avian dinosaurs, early-diverging birds, parrots, and crows•Corvids, like hominins, evolved larger relative brains and bodies simultaneously
Ksepka et al. reconstruct brain-body scaling in a study of >2,000 birds and non-avian dinosaurs. Their results show that avian brain size evolution was profoundly impacted by the K-Pg mass extinction, in the aftermath of which many clades achieved larger relative brain sizes via body size reduction.
The objective of this study was to analyse an association between nailfold capillary abnormalities and the presence and severity of erectile dysfunction (ED) in men with SSc.
A cross-sectional ...analysis of the prospective European League Against Rheumatism (EULAR) Scleroderma Trial and Research database was performed. Men with SSc were included if they had undergone nailfold capillaroscopy and simultaneous ED assessment with the 5-item International Index for Erectile Function (IIEF-5).
Eighty-six men met the inclusion criteria. Eight men (9.3%) had not had sexual intercourse and could not be assigned an IIEF-5 score. Sixty-nine of the 78 men (88.5%) with an IIEF-5 score had nailfold capillary abnormalities, of whom 54 (78.3%) suffered from ED. Nine men (11.5%) had no nailfold capillary abnormalities, of whom six (66.7%) had ED (P = 0.44). ED was more frequent in older men (P = 0.002) and in men with diffuse disease (P = 0.06). Men with abnormal capillaroscopy had a higher median EULAR disease activity than men without (P = 0.02), a lower diffusing capacity of the lung (P = 0.001) and a higher modified Rodnan skin score (P = 0.04), but mean IIEF-5 scores did not differ 15.7 (S.D. 6.2) vs 15.7 (S.D. 6.3). IIEF-5 scores did not differ between men with early (n = 12), active (n = 27) or late (n = 27) patterns (IIEF-5 scores of 17.9, 16.3 and 14.7, respectively). There were no differences in the prevalence of early, active and late capillaroscopy patterns between men with or without ED.
Neither the presence or absence of abnormal capillaroscopy findings nor the subdivision into early, active and late patterns is associated with coexistent ED in SSc.
The early trajectory of skin fibrosis provides insights into the disease course of systemic sclerosis (SSc) including mortality; however, little is known about late skin fibrosis. The aims of our ...study were to ascertain the prevalence and characteristics of late skin fibrosis in SSc.
We developed and tested three conceptual scenarios of late (>5 years after first non-RP feature) skin fibrosis including new worsening of skin disease, and failure to improve after worsening within 5-year window. We defined skin worsening as change in modified Rodnan skin score (mRSS) ≥5 units or ≥25%. Using strict inclusion criteria including complete mRSS, we identified 1,043 (out of 19 115) patients within the EUSTAR database for our analysis. We further restricted analysis within 887 (out of 1043) patients who had lcSSc or dcSSc at baseline.
One-fifth of patients among the whole cohort (n = 208/1043, 19.9%) experienced mRSS worsening, including in patients with lcSSc or dcSSc at baseline (n = 193/887, 21.8%). This was largely due to new skin worsening after the 5-year window or failure to improve with worsening within the 5-year window. Patients with lower baseline mRSS and lcSSc were more likely to develop late skin fibrosis. Anti-Scl-70 was associated with progression from baseline lcSSc to dcSSc, and anticentromere was protective.
Late skin fibrosis is not uncommon in SSc. We have identified different patterns relevant to clinical practice and trial design. Late skin fibrosis is a neglected manifestation of SSc and warrants further investigation including to determine clinical outcomes and optimal therapeutic strategy.
The direction of individual B 8 solar neutrinos has been reconstructed using the SNO + liquid scintillator detector. Prompt, directional Cherenkov light was separated from the slower, isotropic ...scintillation light using time information, and a maximum likelihood method was used to reconstruct the direction of individual scattered electrons. A clear directional signal was observed, correlated with the solar angle. The observation was aided by a period of low primary fluor concentration that resulted in a slower scintillator decay time. This is the first time that event-by-event direction reconstruction in high light-yield liquid scintillator has been demonstrated in a large-scale detector. Published by the American Physical Society 2024
The proportion of patients with ischaemic stroke treated by intravenous (i.v.) recombinant tissue plasminogen activator (rt-PA) is an indicator of quality of stroke care. The objective of the study ...is to evaluate the rate of i.v. thrombolysis in the North-of-France region and its evolution over time. We determined the proportion of inhabitants treated by i.v. rt-PA in 2009–2010 (period A; 8 stroke units, no telemedicine) and 2012 (period B; population campaigns, 12 stroke units with telemedicine in 5). We used hospital registries from the 12 stroke units, and population-based data were collected in a subpopulation of 226,827 inhabitants (5.6 % of the whole population). 1,563 inhabitants received i.v. rt-PA for stroke (period A: 835 in 24 months; period B: 728 in 12 months). Hospital and population data were similar. Annual rates of thrombolysis increased from 103 per million inhabitants 95 % confidence interval (CI) 85–125 to 181 (95 % CI 157–209; relative increase 76 %, 95 % CI 67–83 %). This rate increased in 12 districts (significantly in 6), but the increase was greater in districts where new stroke units, telemedicine, or both were implemented. In conclusion, although the proportion of patients treated was already high in period A, there was still place for improvement. Implementation of new stroke units, extension of the telemedicine network and new population campaigns are necessary to improve the rate of thrombolysis in several areas, to ensure an equal access to treatment over the whole territory. The next step is now to determine whether this high rate of i.v. rt-PA delivery at the population level translates into clinical results.
The Laser Interferometer Gravitational Wave Observatory (LIGO) consists of two widely separated 4 km laser interferometers designed to detect gravitational waves from distant astrophysical sources in ...the frequency range from 10 Hz to 10 kHz. The first observation run of the Advanced LIGO detectors started in September 2015 and ended in January 2016. A strain sensitivity of better than \(10^{-23}/\sqrt{\text{Hz}}\) was achieved around 100 Hz. Understanding both the fundamental and the technical noise sources was critical for increasing the observable volume in the universe. The average distance at which coalescing binary black hole systems with individual masses of 30 \(M_\odot\) could be detected was 1.3 Gpc. Similarly, the range for binary neutron star inspirals was about 75 Mpc. With respect to the initial detectors, the observable volume of Universe increased respectively by a factor 69 and 43. These improvements allowed Advanced LIGO to detect the gravitational wave signal from the binary black hole coalescence, known as GW150914.
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