Data-driven modeling for drop size distributions

The prediction of the drop size distribution (DSD) resulting from liquid atomization is key to the optimization of multiphase flows from gas-turbine propulsion through agriculture to healthcare. Obtaining high-fidelity data of liquid atomization, either experimentally or numerically, is expensive, which makes the exploration of the design space difficult. First, to tackle these challenges, we propose a framework to predict the DSD of a liquid spray based on data as a function of the spray angle, the Reynolds number, and the Weber number. Second, to guide the design of liquid atomizers, the model accurately predicts the volume of fluid contained in drops of specific sizes while providing uncertainty estimation. To do so, we propose a Gaussian process regression (GPR) model, which infers the DSD and its uncertainty form the knowledge of its integrals and of its first moment, i.e., the mean drop diameter. Third, we deploy multiple GPR models to estimate these quantities at arbitrary points of the design space from data obtained from a large number of numerical simulations of a flat fan spray. The kernel used for reconstructing the DSD incorporates prior physical knowledge, which enables the prediction of sharply peaked and heavy-tailed distributions. Fourth, we compare our method with a benchmark approach, which estimates the DSD by interpolating the frequency polygon of the binned drops with a GPR. We show that our integral approach is significantly more accurate, especially in the tail of the distribution (i.e., large, rare drops), and it reduces the bias of the density estimator by up to 10 times. Finally, we discuss physical aspects of the model's predictions and interpret them against experimental results from the literature. This work opens opportunities for modeling drop size distribution in multiphase flows from data

Cambios paleoambientales desde el Pleistoceno tardío hasta el Holoceno medio basados en el registro de diatomeas en la Salina del Bebedero (San Luis, Argentina)

This study analyzes the environmental changes that occurred in the western sector of the San Luis province (Argentina) during the Late Pleistocene to Middle Holocene period (approximately 12,600 to 3,600 years BP). The information provided by diatoms as paleobiological indicators is used for this analysis. We examined the lower 5 meters of the 10-meter-long SBIII core, which was recovered from the endorheic and hypersaline shallow lake known as Salina del Bebedero (33°20’S-66°45’W, 380 m a.s.l.). The observed peaks of relative abundance of the planktonic diatom Cyclotella choctawhatcheeana suggest episodes of substantial water supply to the shallow lake from the Andes mountains via the Desaguadero river. These episodes were interspersed with periods of low water levels, resulting in very shallow to marsh environments characterized by the presence of epiphytic and benthic diatoms. Furthermore, we discuss and integrate the inferred paleoenvironmental information obtained from the diatom records, along with data from other proxies such as pollen and sedimentology. This integration aims to enhance the previously developed paleoenvironmental model for the region, covering the period between approximately 12,600 and 3,600 years BP. Overall, this research significantly contributes to the understanding of diatom assemblages in hypersaline lacustrine systems of the eastern Andes throughout the studied period, revealing the importance of certain taxa as indicators of wetter conditions during the early Holocene and in more recent stages within this timeframe. Additionally, this study aims to expand our existing knowledge of diatoms biodiversity in this province.Este trabajo aporta herramientas de análisis para la comprensión de los cambios ambientales ocurridos en el sector occidental de la provincia de San Luis (Argentina) entre el periodo del Pleistoceno tardío y el Holoceno medio (ca. 12.600 a ca. 3.600 años AP), utilizando la información provista por diatomeas, como indicadores paleobiológicos. Se analizó la mitad inferior del testigo SBIII (10 a 5 m) obtenido en la cuenca endorreica salino-lacustre Salina del Bebedero (33° 20′ S; 66° 45′ O; 380 (m s.n.m.). Los picos de mayor abundancia relativa de la especie planctónica Cyclotella choctawhatcheeana sugieren episodios de gran aporte de agua a la laguna, procedente de la Cordillera de los Andes a través del río Desaguadero. Estos episodios estuvieron intercalados por periodos con bajos niveles lacustres (ambientes someros o palustres) caracterizados por la presencia de diatomeas epifíticas y bentónicas y se identificaron intervalos donde no se encontraron diatomeas. También discutimos y articulamos la información paleoambiental inferida para el período comprendido entre ca. 12.600 y 3.600 años AP, a partir de los registros de diatomeas, con la información disponible de otros proxies (polen y sedimentología), con el fin de mejorar el modelo paleoambiental generado previamente para la región. Este trabajo amplía el conocimiento de ensambles de diatomeas en sistemas lacustres hipersalinos de los Andes orientales durante el periodo estudiado, revelando la importancia de algunos taxones como indicadores de condiciones más húmedas durante el inicio del Holoceno y en etapas más recientes dentro de este periodo y, además, este estudio, profundiza los conocimientos existentes sobre la biodiversidad diatomológica en esta provincia

Amplitude concentration in a phase-modulated spectrum due to femtosecond filamentation

We present a method by which the spectral intensity of an ultrafast laser pulse can be accumulated at selected frequencies by a controllable amount. Using a 4-f pulse shaper we modulate the phase of the frequency components of a femtosecond laser. By inducing femtosecond filamentation with the modulated pulse, we can concentrate the spectral amplitude of the pulse at various frequencies. The phase mask applied by the pulse shaper determines the frequencies for which accumulation occurs, as well as the intensity of the spectral concentration. This technique provides a way to obtain pulses with adjustable amplitude using only phase modulation and the nonlinear response of a medium. This provides a means whereby information which is encoded into spectral phase jumps may be decoded into measurable spectral intensity spikes

Next big challenges in core AI technology

Algorithms and the Foundations of Software technolog

Minimally invasive strabismus surgery (MISS) for inferior obliquus recession

PURPOSE: To present a novel, minimally invasive strabismus surgery (MISS) technique for inferior obliquus recessions. METHODS: Graded MISS inferior obliquus recessions were performed in 20 eyes of 15 patients by applying two small conjunctival cuts, one at the insertion of inferior obliquus and another where the scleral anchoring of the muscle occurred. RESULTS: The amount of recession was 12.2 +/- 2.3 mm (range 6 to 14 mm). The vertical deviation, which was measured in 25 degrees of adduction, decreased from preoperatively 12.8 degrees +/- 5.6 degrees to 2.7 degrees +/- 2.2 degrees (p 0.1). In one eye (2.5%) the two cuts had to be joined because of excessive bleeding. Binocular vision improved in eight patients, remained unchanged in six patients, and decreased from 30 to 60 arcsec in one patient (p > 0.1). Conjunctival and lid swelling were hardly visible on the first postoperative day in primary gaze position in 10/20 (50%) of eyes. Five of the eyes (25%) had mild and five (25%) moderate visibility of surgery. One patient out of 15 (7%) needed repeat surgery because of insufficient reduction of the sursoadduction within the first 6 months. The dose-effect relationship 6 months postoperatively for an accommodative near target at 25 degrees adduction was 0.83 degrees +/- 0.43 degrees per mm of recession. CONCLUSIONS: This study demonstrates that small-incision, minimal dissection inferior obliquus graded recessions are feasible and effective to improve ocular alignment in patients with strabismus sursoadductorius

Rpgrip1 is required for rod outer segment development and ciliary protein trafficking in zebrafish

The authors would like to thank the Royal Society of London, the National Eye Research Centre, the Visual Research Trust, Fight for Sight, the W.H. Ross Foundation, the Rosetrees Trust, and the Glasgow Children’s Hospital Charity for supporting this work. This work was also supported by the Deanship of Scientific Research at King Saud University for funding this research (Research Project) grant number ‘RGP – VPP – 219’.Mutations in the RPGR-interacting protein 1 (RPGRIP1) gene cause recessive Leber congenital amaurosis (LCA), juvenile retinitis pigmentosa (RP) and cone-rod dystrophy. RPGRIP1 interacts with other retinal disease-causing proteins and has been proposed to have a role in ciliary protein transport; however, its function remains elusive. Here, we describe a new zebrafish model carrying a nonsense mutation in the rpgrip1 gene. Rpgrip1homozygous mutants do not form rod outer segments and display mislocalization of rhodopsin, suggesting a role for RPGRIP1 in rhodopsin-bearing vesicle trafficking. Furthermore, Rab8, the key regulator of rhodopsin ciliary trafficking, was mislocalized in photoreceptor cells of rpgrip1 mutants. The degeneration of rod cells is early onset, followed by the death of cone cells. These phenotypes are similar to that observed in LCA and juvenile RP patients. Our data indicate RPGRIP1 is necessary for rod outer segment development through regulating ciliary protein trafficking. The rpgrip1 mutant zebrafish may provide a platform for developing therapeutic treatments for RP patients.Publisher PDFPeer reviewe

Quantum Computing and Quantum Simulation with Group-II Atoms

Recent experimental progress in controlling neutral group-II atoms for optical clocks, and in the production of degenerate gases with group-II atoms has given rise to novel opportunities to address challenges in quantum computing and quantum simulation. In these systems, it is possible to encode qubits in nuclear spin states, which are decoupled from the electronic state in the $^1$S$_0$ ground state and the long-lived $^3$P$_0$ metastable state on the clock transition. This leads to quantum computing scenarios where qubits are stored in long lived nuclear spin states, while electronic states can be accessed independently, for cooling of the atoms, as well as manipulation and readout of the qubits. The high nuclear spin in some fermionic isotopes also offers opportunities for the encoding of multiple qubits on a single atom, as well as providing an opportunity for studying many-body physics in systems with a high spin symmetry. Here we review recent experimental and theoretical progress in these areas, and summarise the advantages and challenges for quantum computing and quantum simulation with group-II atoms.Comment: 11 pages, 7 figures, review for special issue of "Quantum Information Processing" on "Quantum Information with Neutral Particles