Overcoming the adverse effects of substrate on the waveguiding properties of plasmonic nanoparticle chains

International audienceWe have studied numerically the propagation of surface plasmon polaritons (SPPs) in linear periodic chains of plasmonic nanoparticles of different shapes. The chains are deposited on top of a thick dielectric substrate. While in many commonly considered cases the substrate tends to suppress the SPP propagation, we have found that this adverse effect is practically absent in the case when the nanoparticles have the shape of oblate spheroids with sufficiently small aspect ratio (e.g., nanodisks) whose axis of symmetry coincides with the axis of the chain

Revisiting Block-based Quantisation: What is Important for Sub-8-bit LLM Inference?

The inference of Large language models (LLMs) requires immense computation and memory resources. To curtail these costs, quantisation has merged as a promising solution, but existing LLM quantisation mainly focuses on 8-bit. In this work, we explore the statistical and learning properties of the LLM layer and attribute the bottleneck of LLM quantisation to numerical scaling offsets. To address this, we adapt block quantisations for LLMs, a family of methods that share scaling factors across packed numbers. Block quantisations efficiently reduce the numerical scaling offsets solely from an arithmetic perspective, without additional treatments in the computational path. Our nearly-lossless quantised 6-bit LLMs achieve a $19\times$ higher arithmetic density and $5\times$ memory density than the float32 baseline, surpassing the prior art 8-bit quantisation by $2.5\times$ in arithmetic density and $1.2\times$ in memory density, without requiring any data calibration or re-training. We also share our insights into sub-8-bit LLM quantisation, including the mismatch between activation and weight distributions, optimal fine-tuning strategies, and a lower quantisation granularity inherent in the statistical properties of LLMs. The latter two tricks enable nearly-lossless 4-bit LLMs on downstream tasks. Our code is open-sourced.Comment: Accepted by EMNLP202

Excessive number of high asperities for sputtered rough films

The roughness of solids is crucial for interactions between bodies at short separations due to capillary or van der Waals-Casimir forces and for contact mechanics. Specifically, it is critical for the fabrication and operation of microelectromechanical systems, for which functional materials are deposited using thin film coating technologies. Here, it is demonstrated that the materials deposited by magnetron sputtering or thermally evaporated on a cold Si substrate reveal a significantly larger number of high asperities than that predicted by the normal distribution. Such asperities define the distance between the solids in contact that is the key parameter for many problems. The effect is related to the nonequilibrium deposition conditions and is suppressed if the material is deposited on a hot substrate or annealed. The high asperity tails can be described by the extreme value distribution or in some cases by the exponential distribution

Explosion of microbubbles generated by the alternating polarity water electrolysis

Water electrolysis with a fast change of polarity generates a high concentration of bulk nanobubbles containing H2 and O2 gases. When this concentration reaches a critical value, a microbubble pops up, which is terminated quickly in an explosion process. In this paper, we provide experimental information on the phenomenon concentrating on the dynamics of exploding microbubble observed from the top and from the side. An initial bubble with a size of 150 μm expands to a maximum size of 1200 μm for 150 μs and then shrinks in the cavitation process. The sound produced by the event is coming from two sources separated in time: exploding bubble and cavitating bubble. The observed dynamics supports expansion of the bubble with steam but not with H2 and O2 mixture. A qualitative model of this puzzling phenomenon proposed earlier is refined. It is demonstrated that the pressure and temperature in the initial bubble can be evaluated using only the energy conservation law for which the driving energy is the energy of the combusted gas. The temperature in the bubble reaches 200 °C that shows that the process cannot be ignited by standard combustion, but the surface-assisted spontaneous combustion agrees well with the observations and theoretical estimates. The pressure in the microbubble varies with the size of the merging nanobubbles and is evaluated as 10-20 bar. Large pressure difference between the bubble and liquid drives the bubble expansion, and is the source of the sound produced by the process. Exploding microbubbles are a promising principle to drive fast and strong micropumps for microfluidic and other applications

A Unified Software Architecture to Enable Cross-Layer Design in the Future Internet

Abstract—While research on cross-layer network optimization has been progressing, useful implementations have been lagging because the current Internet architecture does not accommodate cross-layering gracefully. As part of our FIND project, we propose a software architecture for the future Internet that is designed to accommodate such interactions. We present a conceptual overview as well as high level software design and an early prototype implementation, and point out the strengths of our architecture. I

Unusual exanthema combined with cerebral vasculitis in pneumococcal meningitis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Bacterial meningitis is a complex, rapidly progressive disease in which neurological injury is caused in part by the causative organism and in part by the host's own inflammatory responses.</p> <p>Case presentation</p> <p>We present the case of a two-year-old Greek girl with pneumococcal meningitis and an atypical curvilinear-like skin eruption, chronologically associated with cerebral vasculitis. A diffusion-weighted MRI scan showed lesions with restricted diffusion, reflecting local areas of immunologically mediated necrotizing vasculitis.</p> <p>Conclusions</p> <p>Atypical presentations of bacterial meningitis may occur, and they can be accompanied by serious unexpected complications.</p

Epidemiology and Outcomes of Critically Ill Children at Risk for Pediatric Acute Respiratory Distress Syndrome:A Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology Study

OBJECTIVES: Interventional trials aimed at pediatric acute respiratory distress syndrome prevention require accurate identification of high-risk patients. In this study, we aimed to characterize the frequency and outcomes of children meeting "at risk for pediatric acute respiratory distress syndrome" criteria as defined by the Pediatric Acute Lung Injury Consensus Conference. DESIGN: Planned substudy of the prospective multicenter, international Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology study conducted during 10 nonconsecutive weeks (May 2016-June 2017). SETTING: Thirty-seven international PICUs. PATIENTS: Three-hundred ten critically ill children meeting Pediatric Acute Lung Injury Consensus Conference "at-risk for pediatric acute respiratory distress syndrome" criteria. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We evaluated the frequency of children at risk for pediatric acute respiratory distress syndrome and rate of subsequent pediatric acute respiratory distress syndrome diagnosis and used multivariable logistic regression to identify factors associated with subsequent pediatric acute respiratory distress syndrome. Frequency of at risk for pediatric acute respiratory distress syndrome was 3.8% (95% CI, 3.4-5.2%) among the 8,122 critically ill children who were screened and 5.8% (95% CI, 5.2-6.4%) among the 5,334 screened children on positive pressure ventilation or high-flow oxygen. Among the 310 at-risk children, median age was 2.1 years (interquartile range, 0.5-7.3 yr). Sixty-six children (21.3%) were subsequently diagnosed with pediatric acute respiratory distress syndrome, a median of 22.6 hours (interquartile range, 9.8-41.0 hr) later. Subsequent pediatric acute respiratory distress syndrome was associated with increased mortality (21.2% vs 3.3%; p < 0.001) and longer durations of invasive ventilation and PICU care. Subsequent pediatric acute respiratory distress syndrome rate did not differ by respiratory support modality at the time of meeting at risk criteria but was independently associated with lower initial saturation:FIO2 ratio, progressive tachycardia, and early diuretic administration. CONCLUSIONS: The Pediatric Acute Lung Injury Consensus Conference "at-risk for pediatric acute respiratory distress syndrome" criteria identify critically ill children at high risk of pediatric acute respiratory distress syndrome and poor outcomes. Interventional trials aimed at pediatric acute respiratory distress syndrome prevention should target patients early in their illness course and include patients on high-flow oxygen and positive pressure ventilation

Solving Data Quality Problems with Desbordante: a Demo

Data profiling is an essential process in modern data-driven industries. One of its critical components is the discovery and validation of complex statistics, including functional dependencies, data constraints, association rules, and others. However, most existing data profiling systems that focus on complex statistics do not provide proper integration with the tools used by contemporary data scientists. This creates a significant barrier to the adoption of these tools in the industry. Moreover, existing systems were not created with industrial-grade workloads in mind. Finally, they do not aim to provide descriptive explanations, i.e. why a given pattern is not found. It is a significant issue as it is essential to understand the underlying reasons for a specific pattern's absence to make informed decisions based on the data. Because of that, these patterns are effectively rest in thin air: their application scope is rather limited, they are rarely used by the broader public. At the same time, as we are going to demonstrate in this presentation, complex statistics can be efficiently used to solve many classic data quality problems. Desbordante is an open-source data profiler that aims to close this gap. It is built with emphasis on industrial application: it is efficient, scalable, resilient to crashes, and provides explanations. Furthermore, it provides seamless Python integration by offloading various costly operations to the C++ core, not only mining. In this demonstration, we show several scenarios that allow end users to solve different data quality problems. Namely, we showcase typo detection, data deduplication, and data anomaly detection scenarios

Adherence to Lung-Protective Ventilation Principles in Pediatric Acute Respiratory Distress Syndrome:A Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology Study

OBJECTIVES: To describe mechanical ventilation management and factors associated with nonadherence to lung-protective ventilation principles in pediatric acute respiratory distress syndrome. DESIGN: A planned ancillary study to a prospective international observational study. Mechanical ventilation management (every 6 hr measurements) during pediatric acute respiratory distress syndrome days 0-3 was described and compared with Pediatric Acute Lung Injury Consensus Conference tidal volume recommendations (< 7 mL/kg in children with impaired respiratory system compliance, < 9 mL/kg in all other children) and the Acute Respiratory Distress Syndrome Network lower positive end-expiratory pressure/higher FIO2 grid recommendations. SETTING: Seventy-one international PICUs. PATIENTS: Children with pediatric acute respiratory distress syndrome. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Analyses included 422 children. On pediatric acute respiratory distress syndrome day 0, median tidal volume was 7.6 mL/kg (interquartile range, 6.3-8.9 mL/kg) and did not differ by pediatric acute respiratory distress syndrome severity. Plateau pressure was not recorded in 97% of measurements. Using delta pressure (peak inspiratory pressure - positive end-expiratory pressure), median tidal volume increased over quartiles of median delta pressure (p = 0.007). Median delta pressure was greater than or equal to 18 cm H2O for all pediatric acute respiratory distress syndrome severity levels. In severe pediatric acute respiratory distress syndrome, tidal volume was greater than or equal to 7 mL/kg 62% of the time, and positive end-expiratory pressure was lower than recommended by the positive end-expiratory pressure/FIO2 grid 70% of the time. In multivariable analysis, tidal volume nonadherence was more common with severe pediatric acute respiratory distress syndrome, fewer PICU admissions/yr, non-European PICUs, higher delta pressure, corticosteroid use, and pressure control mode. Adherence was associated with underweight stature and cuffed endotracheal tubes. In multivariable analysis, positive end-expiratory pressure/FIO2 grid nonadherence was more common with higher pediatric acute respiratory distress syndrome severity, ventilator decisions made primarily by the attending physician, pre-ICU cardiopulmonary resuscitation, underweight stature, and age less than 2 years. Adherence was associated with respiratory therapist involvement in ventilator management and longer time from pediatric acute respiratory distress syndrome diagnosis. Higher nonadherence to tidal volume and positive end-expiratory pressure recommendations were independently associated with higher mortality and longer duration of ventilation after adjustment for confounding variables. In stratified analyses, these associations were primarily influenced by children with severe pediatric acute respiratory distress syndrome. CONCLUSIONS: Nonadherence to lung-protective ventilation principles is common in pediatric acute respiratory distress syndrome and may impact outcome. Modifiable factors exist that may improve adherence