Finding co-solvers on Twitter, with a little help from Linked Data

In this paper we propose a method for suggesting potential collaborators for solving innovation challenges online, based on their competence, similarity of interests and social proximity with the user. We rely on Linked Data to derive a measure of semantic relatedness that we use to enrich both user profiles and innovation problems with additional relevant topics, thereby improving the performance of co-solver recommendation. We evaluate this approach against state of the art methods for query enrichment based on the distribution of topics in user profiles, and demonstrate its usefulness in recommending collaborators that are both complementary in competence and compatible with the user. Our experiments are grounded using data from the social networking service Twitter.com

All-sky search for long-duration gravitational wave transients with initial LIGO

We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

All-sky search for long-duration gravitational wave transients with initial LIGO

We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

SARS-CoV-2 infects the human kidney and drives fibrosis in kidney organoids

Kidney failure is frequently observed during and after COVID-19, but it remains elusive whether this is a direct effect of the virus. Here, we report that SARS-CoV-2 directly infects kidney cells and is associated with increased tubule-interstitial kidney fibrosis in patient autopsy samples. To study direct effects of the virus on the kidney independent of systemic effects of COVID-19, we infected human-induced pluripotent stem-cell-derived kidney organoids with SARS-CoV-2. Single-cell RNA sequencing indicated injury and dedifferentiation of infected cells with activation of profibrotic signaling pathways. Importantly, SARS-CoV-2 infection also led to increased collagen 1 protein expression in organoids. A SARS-CoV-2 protease inhibitor was able to ameliorate the infection of kidney cells by SARS-CoV-2. Our results suggest that SARS-CoV-2 can directly infect kidney cells and induce cell injury with subsequent fibrosis. These data could explain both acute kidney injury in COVID-19 patients and the development of chronic kidney disease in long COVID

Variation in neurosurgical management of traumatic brain injury

Background: Neurosurgical management of traumatic brain injury (TBI) is challenging, with only low-quality evidence. We aimed to explore differences in neurosurgical strategies for TBI across Europe. Methods: A survey was sent to 68 centers participating in the Collaborative European Neurotrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study. The questionnaire contained 21 questions, including the decision when to operate (or not) on traumatic acute subdural hematoma (ASDH) and intracerebral hematoma (ICH), and when to perform a decompressive craniectomy (DC) in raised intracranial pressure (ICP). Results: The survey was completed by 68 centers (100%). On average, 10 neurosurgeons work in each trauma center. In all centers, a neurosurgeon was available within 30 min. Forty percent of responders reported a thickness or volume threshold for evacuation of an ASDH. Most responders (78%) decide on a primary DC in evacuating an ASDH during the operation, when swelling is present. For ICH, 3% would perform an evacuation directly to prevent secondary deterioration and 66% only in case of clinical deterioration. Most respondents (91%) reported to consider a DC for refractory high ICP. The reported cut-off ICP for DC in refractory high ICP, however, differed: 60% uses 25 mmHg, 18% 30 mmHg, and 17% 20 mmHg. Treatment strategies varied substantially between regions, specifically for the threshold for ASDH surgery and DC for refractory raised ICP. Also within center variation was present: 31% reported variation within the hospital for inserting an ICP monitor and 43% for evacuating mass lesions. Conclusion: Despite a homogeneous organization, considerable practice variation exists of neurosurgical strategies for TBI in Europe. These results provide an incentive for comparative effectiveness research to determine elements of effective neurosurgical care

Nanowatt photonics of structural transformations in a single nanoparticle

Metallic nanoparticles have the potential to play a key role in future, highly-integrated photonic devices, not only as elements of waveguiding structures; (in plasmonic wave-guiding chains, or as scattering centres in band-gap structures), but also as active all-optical switching elements operating at very low power levels. We show that this functionality can be achieved by reversibly controlling the phase composition, and thereby the optical properties, of a nanoparticle with optical excitation at nanowatt power levels. For the first time, phase transition phenomena and associated optical effects have been studied in a single gallium nanoparticle, i.e. without the inhomogeneous broadening associated with size and shape distributions in nanoparticle films. We have been able to dynamically control coexistences between various combinations of galliums crystalline and disordered phases in very narrow temperature intervals and to detect substantial changes in optical properties at very low power levels. The nanoparticle was grown on the aperture at the tip of a gold-coated, tapered silica optical fibre. Its optical characteristics were then studied, at temperatures between 80 and 300 K, using low power infrared diode lasers. Power levels as low as 5 nW were found to be sufficient to substantially alter the particles reflectivity and transmission. The light-induced changes are fully reversible, with relaxation times in the microsecond range, and are critically enhanced near the transition temperatures between gallium’s metastable crystalline phases and the liquid. Such behaviour indicates that structural transformations, including solid-solid transitions between different crystalline forms, occur continuously, through the dynamic coexistence of phases

Controlling the optical properties of a single nanoparticle at nanowatt power levels

The phase composition and optical properties of a nanoparticle can be controlled with light. This effect has been studied, without inhomogeneous broadening, in a single gallium nanoparticle on the tip of a tapered optical fiber

All-optical phase-change memory in a single nanoparticle

Conventional electronic memories face a challenge in the reduction of size and power consumption as required for meeting the future demand on data storage and access. Phase-change memories have been suggested as candidates for solving this issue, with data recording done by switching the material between an amorphous and a crystalline phase, much in line with today's DVD/DVR technology for optical recording, and even the writing of individual dislocations has been reported. However, polymorphic systems exist in which other crystalline-to-crystalline transitions can provide for higher base logics. Here we demonstrate the principle of a four-level optical memory element obtained by using the phase of a single gallium nanoparticle of 80 nm size, with the four logical states of the memory written by optical pulses of a few pJ energy. The quaternary-logical memory element we demonstrate is comparable in size with the next-generation data storage elements and radically smaller than previously employed diffraction-limited optical memory elements. In addition, the energy required for switching the logical state of the nanoparticle is found to be one order of magnitude less than that of writing a bit in today's DVD/DVR or hard disk technology. This novel principle of operation has implications not only to optical memories and switching, but equally well applies as a key element for achieving plasmonic switching