The Relocation Problem of Field Calibrated Low-Cost Sensor Systems in Air Quality Monitoring: A Sampling Bias.

This publication revises the deteriorated performance of field calibrated low-cost sensor systems after spatial and temporal relocation, which is often reported for air quality monitoring devices that use machine learning models as part of their software to compensate for cross-sensitivities or interferences with environmental parameters. The cause of this relocation problem and its relationship to the chosen algorithm is elucidated using published experimental data in combination with techniques from data science. Thus, the origin is traced back to insufficient sampling of data that is used for calibration followed by the incorporation of bias into models. Biases often stem from non-representative data and are a common problem in machine learning, and more generally in artificial intelligence, and as such a rising concern. Finally, bias is believed to be partly reducible in this specific application by using balanced data sets generated in well-controlled laboratory experiments, although not trivial due to the need for infrastructure and professional competence.

Juniper Subtle Energy Healing: A Case Study.

OBJECTIVES: This pilot case study sought to examine the efficacy of subtle energy treatments as conducted by Buddhist healing master Segyu Rinpoche at his Juniper Integrative Clinic in Northern California. DESIGN: Over the course of a year, this study followed two patients with terminal diagnoses, their treating physicians, and Segyu Rinpoche as the patients underwent treatment at the Juniper Clinic. The patients entering the study had exhausted all known medical options. One patient suffered from chronic lymphocytic leukemia [CLL] and the other from bronchiolitis obliterans [BOS] brought about by graft versus host disease following a bone marrow transplant for leukemia. Their treating physicians are prominent members of two different teaching/research hospitals. This was an IRB approved study conducted in conformity with HIPAA standards. SETTING: The patients participated in treatments with Segyu Rinpoche twice a month at his clinic and engaged in daily meditation as instructed by Rinpoche. The study followed both patients through in-depth, face-to-face interviews, wellness surveys, weekly journal entries, and medical records. The study also followed the physicians and Segyu Rinpoche through face-to-face interviews. RESULTS: Both patients and physicians identified significant shifts in patient wellbeing, including less pain, greater happiness and more ease. In addition, both physicians and patients reported a reduced need for medication. Some aspects of the design were more or less successful in tracking patient experience (i.e., health and wellness survey vs. personal journals). The success of the pilot indicates that more qualitative case studies are needed. CONCLUSIONS: Patients and physicians identified a significant increase in overall patient wellbeing. Hence, on an anecdotal level, the study demonstrated the usefulness of subtle energy healing as practiced by Segyu Rinpoche and the Juniper Clinic. The success of the pilot indicates the potential value of full qualitative studies for this modality.

Compact devices for generation of reference trace VOC mixtures: a new concept in assuring quality at chemical and biochemical laboratories.

Volatile organic compounds (VOCs) in gas mixtures at trace level (nmol/mol) are routinely measured by chemical and biochemical laboratories as climate indicators, indoor air quality pollutants from building materials emissions, contaminants in food and beverages, and biomarkers in body fluids (blood, urine, breath) of occupational exposure or human diseases. Current analytical instruments used for measurements are gas chromatographs equipped with various injector and detector configurations. The assurance of measurement quality is done by using a huge amount of certified liquid VOC standard solutions (or gaseous VOC standard cylinders) with multiple dilutions to reach the required trace level. This causes high standard uncertainty in instrument calibrations, high cost, and high consumption of analysis and laboratory personal time. In this paper, we present the implementation of portable generators producing VOC gas standards at trace level for automatic and direct calibration of VOC detectors employed in various contexts, removing the need for preparation of matrix calibration standards in cylinders. Two compact devices in-house developed by two national metrology institutes-the Istituto Nazionale di Ricerca Metrologica (INRIM) and the Federal Institute of Metrology (METAS)-are here used to dynamically generate reference gas mixtures in an SI traceable way. The two devices are based on different technologies: diffusion and permeation, for INRIM and METAS, respectively. A metrological characterization is given and the practical implementation at chemical and biochemical laboratories is discussed. Graphical abstract Onsite calibration with transportable generation system with similar performances to primary laboratory devices.