Complex loading and simulation of acoustic thickness shear mode resonator

During the last decades thickness shear mode resonators (TSM, QCM) have been object of comprehensive research. Many approaches were made to describe the behavior and physical effects when loaded. We present a physical model that describes the TSM in the full frequency range, including overtones for a large variety of loadings (e.g. gases, liquids or solid materials). By using an automated curve fit algorithm, absolute values for the loaded material (e.g. thickness, viscosity) can be extracted. The model has been validated with a large number of experiments including liquids with complex viscosities, biomolecule interactions, electrochemisty or vacuum deposition techniques. Additionally, the appearance of layer resonances have been predicted and verified. Layer resonances are remarkable because they appear at even-numbered overtones, which have been considered to be impossible

Spectral signatures of excess-proton waiting and transfer-path dynamics in aqueous hydrochloric acid solutions

Signatures of solvated excess protons in infrared difference absorption spectra, such as the continuum band between the water bend and stretch bands, have been experimentally known for a long time, but the theoretical basis for linking spectral signatures with the microscopic proton-transfer mechanism so far relied on normal-mode analysis. We analyze the excess-proton dynamics in ab initio molecular-dynamics simulations of aqueous hydrochloric acid solutions by trajectory-decomposition techniques. The continuum band in the 2000 - 3000 cm$^{-1 }$ range is shown to be due to normal-mode oscillations of temporary H$_3$O$^+$ complexes. An additional prominent peak at 400 cm$^{-1}$ reports on the coupling of excess-proton motion to the relative vibrations of the two flanking water molecules. The actual proton transfer between two water molecules, which for large water separations involves crossing of a barrier and thus is not a normal mode, is characterized by two characteristic time scales: Firstly, the waiting time for transfer to occur in the range of 200 - 300 fs, which leads to a broad weak shoulder around ~100 cm$^{-1}$, consistent with our experimental THz spectra. Secondly, the mean duration of a transfer event of about 14 fs, which produces a rather well-defined spectral contribution around 1200 cm$^{-1}$ and agrees in location and width with previous experimental mid-infrared spectra

Intersectionality as a tool for clinical ethics consultation in mental healthcare.

Bioethics increasingly recognizes the impact of discriminatory practices based on social categories such as race, gender, sexual orientation or ability on clinical practice. Accordingly, major bioethics associations have stressed that identifying and countering structural discrimination in clinical ethics consultations is a professional obligation of clinical ethics consultants. Yet, it is still unclear how clinical ethics consultants can fulfill this obligation. More specifically, clinical ethics needs both theoretical tools to analyze and practical strategies to address structural discrimination within clinical ethics consultations. Intersectionality, a concept developed in Black feminist scholarship, is increasingly considered in bioethical theory. It stresses how social structures and practices determine social positions of privilege and disadvantage in multiple, mutually co-constitutive systems of oppression. This article aims to investigate how intersectionality can contribute to addressing structural discrimination in clinical ethics consultations with a particular focus on mental healthcare. To this end, we critically review existing approaches for clinical ethics consultants to address structural racism in clinical ethics consultations and extend them by intersectional considerations. We argue that intersectionality is a suitable tool to address structural discrimination within clinical ethics consultations and show that it can be practically implemented in two complementary ways: 1) as an analytic approach and 2) as a critical practice

A methodology for collecting donning times of thermal protective immersion suits intended to be worn by passengers on vessels operating in cold environments

Adequate thermal protection for passengers travelling on-board vessels in cold climate regions, such as that provided by thermal protective immersion suits (TPIS), enhances passenger survivability in emergency situations, in particular those requiring the abandonment of the vessel. As emergency abandonment is a time critical process, it is essential to consider the time required to correctly don the TPIS. Testing standards, such as the International Maritime Organization guidelines, require that TPIS must be able to be donned within 2 minutes. Unfortunately, current practices quantifying donning times are questionable and so there is a limited evidence base that reliably quantifies donning times required by typical passengers. This paper presents a test procedure designed to reliably quantify the time required by test subjects to don the TPIS. Furthermore, the procedure assesses the donning correctness – a TPIS that is incorrectly donned is unlikely to offer appropriate thermal protection. The paper will also discuss the deficiencies in current practices to assess required donning time

As above, so below: deposition, modification, and reutilization of human remains at Marmoles cave (Cueva de los Marmoles: Southern Spain, 4000–1000 cal BCE)

The deposition and manipulation of human remains in natural caves are well known for the Neolithic of Southern Iberia. The cultural meaning of these practices is however still largely unclear. Cueva de los Marmoles (CM, Priego-Córdoba) is one of the most important cave contexts from Southern Spain, which returned a large number of commingled skeletal remains suggesting its funerary use from the Neolithic to the Late Bronze Age. Here we discuss CM from a chronological and cultural perspective based on new radiocarbon, anthropological, and taphonomic analyses. These include the estimation of the minimum number of individuals, the exploration of fragmentation patterns characterizing different skeletal regions, and the macroscopic and microscopic analysis of modifications to the remains of possible anthropic origin. Radiocarbon data point at a funerary use of CM between the 5th–2nd millennium cal. BCE. MNI estimates reveal the presence of at least 12 individuals (seven adults and five nonadults). The low representation of elements from hands and feet suggests that individuals were placed in the cave while partially decomposed. Anthropic traces on the remains (fresh fractures, modification of marrow canal, scraping marks) hint at their intentional fragmentation, cleaning from residual soft tissues, and in some cases reutilization. These practices are well-exemplified by the recovery of one «skull cup» and of two long bones used as tools. These data align with those from other cave contexts from the same geographic region, suggesting the presence, especially during the Neolithic period, of shared ideologies centered on the human body

Observation of optical feedback dynamics in single-mode terahertz quantum cascade lasers: Transient instabilities

We provide an experimental evidence of transient instabilities (TIs) in a terahertz (THz) quantum cascade laser (QCL) under optical feedback, in contrast to the widely accepted claim that THz QCLs are ultrastable against feedback. The TIs appear as periodic oscillations in emitted power or terminal voltage of the laser with an increasing oscillation frequency as feedback increases. The absence of relaxation oscillations and low linewidth enhancement factor in THz QCLs makes them a platform uniquely suitable for exploring external-cavity-related dynamics in semiconductor lasers. This work opens a pathway to a THz sensing and imaging modality based on these TIs, which has much reduced complexity compared to existing approaches using laser feedback interferometry