Physical Units Research Articles

GaiaData Release 3

GaiaData Release 3 provides novel flux-calibrated low-resolution spectrophotometry for ≃220 million sources in the wavelength range 330 nm ≤λ≤ 1050 nm (XP spectra). Synthetic photometry directly tied to a flux in physical units can be obtained from these spectra for any passband fully enclosed in this wavelength range. We describe how synthetic photometry can be obtained from XP spectra, illustrating the performance that can be achieved under a range of different conditions – for example passband width and wavelength range – as well as the limits and the problems affecting it. Existing top-quality photometry can be reproduced within a few per cent over a wide range of magnitudes and colour, for wide and medium bands, and with up to millimag accuracy when synthetic photometry is standardised with respect to these external sources. Some examples of potential scientific application are presented, including the detection of multiple populations in globular clusters, the estimation of metallicity extended to the very metal-poor regime, and the classification of white dwarfs. A catalogue providing standardised photometry for ≃2.2 × 108sources in several wide bands of widely used photometric systems is provided (GaiaSynthetic Photometry Catalogue; GSPC) as well as a catalogue of ≃105white dwarfs with DA/non-DA classification obtained with a Random Forest algorithm (GaiaSynthetic Photometry Catalogue for White Dwarfs; GSPC-WD).

A study on optimization of polling schedule to minimize the number of frames for in-vehicle UWB wireless network

This paper discusses a polling and scheduling method for UWB-based in-vehicle networks. In IEEE 802.15.4a/z, conveying as much sensor data as possible in a Physical layer Protocol Data Unit (PPDU) is more efficient. Therefore, this paper proposes a scheduling scheme that minimizes the number of frames to be transmitted by adjusting the readout phase of periodic sensor data. Compared to existing methods, our proposed method can aggregate sensor data into fewer frames, resulting in a decreased loss rate in our experiment.

Smart all-time vision: The battery-free video communication for urban administration and law enforcement

The Chinese government is dedicated to enhancing the level of informatization in administrative law enforcement to ensure fairness and increase credibility. Currently, law enforcement has exposed such problems as insufficient force, difficulties in collecting evidence, and low evidential power. These problems contradict the principles of rule of law and standardization. Many local governments have implemented advanced information technologies for urban administration and law enforcement, including big data, artificial intelligence, and IoT. Among these technologies, IoT is the core communication infrastructure for innovative law enforcement platforms. However, traditional video communications rely on batteries or dedicated power sources, leading to maintenance challenges and high power consumption. In this paper, we propose AT-Eye, a new video communication paradigm for all-time law enforcement video monitoring, which is battery-free and high-throughput. The key enabler of AT-Eye is ambient backscatter technology, which enables energy harvesting and video communication simultaneously. Unlike previous methods, our proposal introduces a novel CCK-based modulation for tag cameras and achieves 4-way concurrency. The modulation is simple because it uses phase difference and it is energy-efficient because generating square waves is adequate. Moreover, to ensure full compatibility with COTS WiFi, we modulate the physical service data unit. Therefore, data recovery is possible using only commercial NICs. We conduct comprehensive experiments to examine our proposal and experiment results show that AT-Eye achieves a throughput of 10.8 Mbps with COTS radios. We also simulate a 16-way battery-free tag camera system, demonstrating AT-Eye's feasibility of high-definition video communication.

Printed Metasurface Leaky Wave Antennas Based on Penetrable Aperture Field Synthesis

A design methodology for 1-D modulated printed metasurface leaky-wave antennas (LWAs) with a pattern synthesis capability in 2-D TE polarization is presented. For a desired radiation pattern, complete tangential fields on the surface of a grounded dielectric substrate are constructed and optimized to find a pointwise passive surface impedance distribution. Dielectric and conductor losses are taken into account in the field synthesis process via a design curve obtained using analysis of a physical unit cell with lossy constituents. It enables accurate prediction of the aperture field distribution when practical lossy materials are used. A spatially modulated impedance can be realized using an array of printed copper strips. Three 10-wavelength-long LWA designs are demonstrated numerically for broadside, two-beam, and sector patterns. The LWA for broadside radiation is fabricated and measured, showing a good agreement with the simulation results.

Interrater reproducibility of the Myoton and durometer devices to quantify sclerotic chronic graft-versus-host disease.

Chronic graft-versus-host disease (cGVHD) is a severe complication in long-term survivors of allogeneic hematopoietic stem cell transplantation. This disease is challenging to manage clinically due to a lack of validated tools to quantitatively measure skin sclerosis. The current gold standard for measuring skin sclerosis is the NIH Skin Score which has only moderate agreement among clinicians and experts. To more accurately assess skin sclerosis in cGVHD, the Myoton and durometer devices can be used to directly measure biomechanical parameters of the skin. However, the reproducibility of these devices is not known in patients with cGVHD. To determine this reproducibility, three observers independently measured 10 anatomic sites in each of seven patients with sclerotic cGVHD using the Myoton and durometer. Clinical reproducibility was measured by mean pairwise differences (U-statistic) and intraclass correlation coefficients (ICCs) with 95% confidence intervals (CIs). Mean pairwise differences, expressed in true physical units, were used to report typical errors for each anatomic site and device. Mean pairwise differences were less than 11% of the average overall values for all five Myoton parameters and durometer hardness. These were lower for Myoton creep (4.1%), relaxation time (4.7%), and frequency (5.1%) than decrement (9.0%), stiffness (10.4%), and durometer hardness (9.0%). Myoton parameters creep, relaxation time, and frequency showed promise for capturing skin biomechanics more accurately than Myoton stiffness, decrement, or durometer hardness. Mean pairwise differences trended highest in the shin and volar forearm and lowest in the dorsal forearm. The interobserver ICC for overall (averaged across all measured body sites of a patient) creep (0.94; 95% CI 0.87-1.00), relaxation time (0.96; 95% CI 0.90-1.00), and frequency (0.95; 95% CI 0.88-1.00), trended higher than that for decrement (0.43; 95% CI 0.00-0.88), stiffness (0.92; 95% CI 0.81-1.00), and durometer hardness (0.82; 95% CI 0.61-1.00). Similar trends were observed in healthy participants. These findings can help clinicians design better studies to assess therapeutic response to new cGVHD treatments and support the interpretation of future measurements.

Design, realization and characterization of a free-floating platform for flexible satellite control experiments

Experimental verification of numerical models is a key aspect in all scientific and technological disciplines, yet space systems can be particularly hard to test on ground: in fact, a terrestrial mock-up replicating the orbital dynamics should be in a microgravity environment. One of the most common approaches to (at least partially) realize this condition, consists in free-floating systems, in which the friction between an experimental platform and the working surface is almost completely removed. The vertical axis is still subject to gravity, and only 3° of freedom (two horizontal translations and one rotation about the vertical axis) are available to replicate the orbital behavior.Our research group had been developing since 2012 a free-floating platform named PINOCCHIO (Platform Integrating Navigation and Orbital Control Capabilities Hosting Intelligent Onboard). The need to investigate with higher accuracy the attitude control problem for flexible satellites called for the design, realization and characterization of a new platform with enhanced performance.This paper describes the main components of the system, including the pressure air system, the navigation and communication system, the Guidance, Navigation and Control (GNC) architecture and relevant hardware. The attention is specifically on the characterization of the subsystems' performance. The physical (mass, moment of inertia), control (thrusters’ torque and force) and Inertial Measurement Unit (IMU) characteristics are experimentally measured with the associated uncertainty level. The accuracy of the external metrology system in static and dynamic conditions is also characterized, obtaining a 100 μm-level resolution for external measurement of rigid and elastic displacements; this information is fundamental for performing tests of fine pointing control algorithms for flexible and agile satellites.The proposed characterization methodology and associated results could be of interest for university and industry laboratories intended to develop new free-floating platforms.

Predicting article quality scores with machine learning: The U.K. Research Excellence Framework

AbstractNational research evaluation initiatives and incentive schemes choose between simplistic quantitative indicators and time-consuming peer/expert review, sometimes supported by bibliometrics. Here we assess whether machine learning could provide a third alternative, estimating article quality using more multiple bibliometric and metadata inputs. We investigated this using provisional three-level REF2021 peer review scores for 84,966 articles submitted to the U.K. Research Excellence Framework 2021, matching a Scopus record 2014–18 and with a substantial abstract. We found that accuracy is highest in the medical and physical sciences Units of Assessment (UoAs) and economics, reaching 42% above the baseline (72% overall) in the best case. This is based on 1,000 bibliometric inputs and half of the articles used for training in each UoA. Prediction accuracies above the baseline for the social science, mathematics, engineering, arts, and humanities UoAs were much lower or close to zero. The Random Forest Classifier (standard or ordinal) and Extreme Gradient Boosting Classifier algorithms performed best from the 32 tested. Accuracy was lower if UoAs were merged or replaced by Scopus broad categories. We increased accuracy with an active learning strategy and by selecting articles with higher prediction probabilities, but this substantially reduced the number of scores predicted.

Bring in the Clowns

There is no unique definition of circus pedagogy; however, “scholars agree that such a discipline could provide a valid alternative to learn and deepen various mobility contents”. This article aims to provide strategies for implementing an elementary physical education Circus Unit. An overview of how to design three basic routines of a circus program (balances, manipulatives, and clowning) is included, along with a description of how to execute a final performance. Lastly, a description of how the unit aligns with National Standard goals is provided. Now is the time for you to dip your foot into the circus world and make it come alive for your students.

On the concepts and correct use of radiometric quantities for assessing the light environment and their application to plant research.

Light is one of the most important factors for photosynthetic organisms to grow. Historically, the amount of light in plant sciences has been referred to as light intensity, irradiance, photosynthetic active radiation, photon flux, photon flux density, etc. On occasion, all these terms are used interchangeably, yet they refer to different physical units and each metric offers distinct information. Even for experts in the fields of plant photobiology, the use of these terms is confusing, and there is a loose implementation of each concept. This makes the use of radiometric units even more confusing to non-experts when looking for ways to measure light, since they could easily feel overwhelmed by the specialized literature. The use of scientific concepts must be accurate, as ambiguity in the use of radiometric quantities can lead to inconsistencies in analysis, thus decreasing the comparability between experiments and to the formulation of incorrect experimental designs. In this review, we provide a simple yet comprehensive view of the use of radiometric quantities in an effort to clarify their meaning and applications. To facilitate understanding, we adopt a minimum amount of mathematical expressions and provide a historical summary of the use of radiometry (with emphasis on plant sciences), examples of uses, and a review of the available instrumentation for radiometric measurements.

Historical geomagnetic observations from Prague observatory (since 1839) and their contribution to geomagnetic research

Abstract. Shortly after the introduction of the physical unit for the magnetic field in 1832 and the invention of the bifilar apparatus in 1837, both being extraordinary scientific achievements that took place in Göttingen, the Clementinum observatory in Prague became one of the first places where systematic observations of the horizontal intensity of the geomagnetic field began. Karl Kreil was decisively responsible for this. In this paper, we focus on the very beginnings of geomagnetic observations in Prague, dating from the middle of 1839. We describe the archival materials with data that exist from that time, how the main instrument for observing magnetic storms – the bifilar magnetometer – worked and how it was calibrated, and the first magnetic survey in Bohemia. This study indicates the importance of historical geomagnetic observation materials to modern science, such as space weather research.

Reacondicionamiento de la Atención Primaria de Salud para enfrentar la pandemia COVID 19 y percepción de los profesionales sobre las medidas emprendidas en un municipio brasileño

Objective: to describe the Primary Care (PC) scenario regarding reconditioning, equipment and organization of services in order to face the pandemic and to measure the perception by professionals regarding these adaptations. Method: a research with mixed method in a city of the San Pablo state (Brazil). In the quantitative stage, a descriptive cross-sectional study was conducted in 222 PC professionals; the adapted Risk assessment and management of exposure of health care workers in the context of COVID-19 questionnaire by the World Health Organization was implemented. This was followed by the qualitative approach, which consisted in field observation in four PC units. Results: out of the total, 86.94% (n= 193) mentioned that there was an assessment of the signs and symptoms of the users before consultation; 63.96% (n=142) stated that a daily cleaning routine was followed in the waiting room; 92.34% (n= 205) claimed that there were methods available for hand hygiene; 77.48% (n= 172) said that appointments were scheduled in order to maintain physical distancing; 80.12% (n= 178) had not conducted any reconditioning work, and 45.95% (n=102) provided educational materials to users. Conclusions: during field observation, some assessments for signs and symptoms in users were detected; no cleaning actions were observed in the units, it was perceived that there was not enough alcohol gel in the dispenser, there were no marks on the floor to keep distancing, there was a lack of educational materials, and it was not verified that any reconditioning work had been conducted. During data integration, there was convergence regarding physical structure and unit reconditioning.

The miniJPAS survey: AGN and host galaxy coevolution of X-ray-selected sources

Studies indicate strong evidence of a scaling relation in the local Universe between the supermassive black hole mass (MBH) and the stellar mass of their host galaxies (M⋆). They even show similar histories across cosmic times of their differential terms: the star formation rate (SFR) and black hole accretion rate (BHAR). However, a clear picture of this coevolution is far from being understood. We selected an X-ray sample of active galactic nuclei (AGN) up to z = 2.5 in the miniJPAS footprint. Their X-ray to infrared spectral energy distributions (SEDs) have been modeled with the CIGALE code, constraining the emission to 68 bands, from which 54 are the narrow filters from the miniJPAS survey. For a final sample of 308 galaxies, we derived their physical properties, such as their M⋆, SFR, star formation history (SFH), and the luminosity produced by the accretion process of the central BH (LAGN). For a subsample of 113 sources, we also fit their optical spectra to obtain the gas velocity dispersion from the broad emission lines and estimated the MBH. We calculated the BHAR in physical units depending on two radiative efficiency regimes. We find that the Eddington ratios (λEdd) and its popular proxy (LX/M⋆) have a difference of 0.6 dex, on average, and a KS test indicates that they come from different distributions. Our sources exhibit a considerable scatter on the MBH − M⋆ scaling relation, which can explain the difference between λEdd and its proxy. We also modeled three evolution scenarios for each source to recover the integral properties at z = 0. Using the SFR and BHAR, we show a notable diminution in the scattering between MBH − M⋆. For the last scenario, we considered the SFH and a simple energy budget for the AGN accretion, and we retrieved a relation similar to the calibrations known for the local Universe. Our study covers ∼1 deg2 in the sky and is sensitive to biases in luminosity. Nevertheless, we show that, for bright sources, the link between the differential values (SFR and BHAR) and their decoupling based on an energy limit is the key that leads to the local MBH − M⋆ scaling relation. In the future, we plan to extend this methodology to a thousand degrees of the sky using JPAS with an X-ray selection from eROSITA, to obtain an unbiased distribution of BHAR and Eddington ratios.

Butterfly-Inspired Tri-State Photonic Crystal Composite Film for Multilevel Information Encryption and Anti-Counterfeiting.

Counterfeiting is a worldwide issue and has long troubled legitimate businesses, while nowadays anti-counterfeiting materials and technology are still insufficient to combat the escalating counterfeit behaviors. Inspired by hindwing structure of Troides magellanus, a new kind of anti-counterfeiting material taking advantage of both physical and chemical structures to display multiple optical states is prepared. The chemical units (luminescent lanthanide) are blended with physical units (monodispersed colloidal particles) and mediating molecules, which are then assembled into a photonic crystal structure at room temperature in less than 10s through a new assembly technique called molecule-mediated shear-induced assembly technique (MSAT). The as-prepared photonic crystal films feature three unique optical states, each displaying structural, fluorescent, and phosphorescent color under different lighting conditions, which integrates colors from both physical and chemical origins. Furthermore, by incorporating different luminescent materials into different parts of the photonic crystal pattern, a high-level information encryption system is designed to be capable of carrying three distinct types of information. Thanks to this powerful tool of MSAT, it is now possible to assemble different-sized, even irregular non-spherical units with monodispersed spherical units into high-quality photonic crystal films, which provides easy access to incorporating new features into photonic crystal systems.

Learning Outcomes of Particle Physics

In recent years, many researches and experiments have been carried out in the field of particle physics in our world, and important results have been achieved. The results of the research are transferred to the field of education, the curricula and the books taught are updated. The subject of particle physics is given in the 4th unit of the High School Physics Curriculum. In the study, particle physics learning outcomes given in the Introduction to Atomic Physics and Radioactivity unit were examined scientifically and educationally. With the document analysis method, one of the qualitative research methods, the subjects and achievements given in the relevant unit were determined first. Then, the quantitative and qualitative status, scientific and educational features and actuality of the learning outcomes were evaluated. Then, it was compared whether the achievements were compatible with the program objectives. At the end of the research, it was seen that the learning outcomes were aimed at teaching knowledge, scientific skills and competencies were secondary, the suggested teaching methods and techniques were inadequate, and the outcomes met the program objectives at a limited level. For an effective particle physics teaching in our country, it has been suggested that the high school physics curriculum should be updated, the learning outcomes should be compatible with the program, and the numerical, scientific and educational aspects should be determined well. In addition, it is recommended to focus on skills such as research, experiment, observation, classification, comparison and questioning in the teaching process, and to benefit from information and communication technologies with current methods and techniques.

Skateboarding: Relevant, Exciting and Fun

Skateboarding has become a common means of transportation and physical activity among adolescents and adults going to and from work or across college campuses, further highlighting why its implementation as a physical education unit makes sense. This article gives readers a more robust understanding of skateboarding, why it could be advantageous to include in physical education curricula, the general cost of equipment, and an example eight-day skateboarding unit. The aim is to encourage more educators to consider including it in their physical education curriculum.

Absolute Ca II H & K and H-alpha flux measurements of low-mass stars: Extending R′HK to M dwarfs

Context. With the recent surge of planetary surveys focusing on detecting Earth-mass planets around M dwarfs, it is becoming more important to understand chromospheric activity in M dwarfs. Stellar chromospheric calcium emission is typically measured using the R′HK calibrations of Noyes et al. (1984), which are only valid for 0.44 ≤ B – V ≤ 0.82. Measurements of calcium emission for cooler dwarfs B – V ≥ 0.82 are difficult because of their intrinsic dimness in the blue end of the visible spectrum. Aims. We measure the absolute Ca II H & K and Hα flux of a sample of 110 HARPS M dwarfs and also extend the calibration of R′HK to the M dwarf regime using PHOENIX stellar atmosphere models. Methods. We normalized a template spectrum with a high signal-to-noise ratio that was obtained by coadding multiple spectra of the same star to a PHOENIX stellar atmosphere model to measure the chromospheric Ca II H & K and Ha flux in physical units. We used three different Teff calibrations and investigated their effect on Ca II H & K and Hα activity measurements. We performed conversions of the Mount Wilson S index to R′HK as a function of effective temperature for the range 2300 K ≤ Teff ≤ 7200 K. Last, we calculated continuum luminosity χ values for Ca II H & K and Hα in the same manner as West & Hawley (2008) for –1.0 ≤ [Fe/H] ≤ + 1.0 in steps of Δ [Fe/H] = 0.5. Results. We compare different Teff calibrations and find ΔΤeff ~ several 100 K for mid- to late-M dwarfs. Using these different Teff calibrations, we establish a catalog of log R′HK and ℱ′Hα/ℱbol measurements for 110 HARPS M dwarfs. The difference between our results and the calibrations of Noyes et al. (1984) is Δ log R′HK = 0.01 dex for a Sun-like star. Our χ values agree well with those of West & Hawley (2008). We confirm that the lower boundary of chromospheric Ca II H and K activity does not increase toward later-M dwarfs: it either stays constant or decreases, depending on the Teff calibration used. We also confirm that for Ha, the lower boundary of chromospheric flux is in absorption for earlier -M dwarfs and fills into the continuum toward later M dwarfs. Conclusions. We confirm that we can effectively measure R′HK in M dwarfs using template spectra with a high signal-to-noise ratio. We also conclude that our calibrations are a reliable extension of previous R′HK calibrations, and effective temperature calibration is the main source of error in our activity measurements.

Engineering Properties of Cementless Alkali Activated CLSM Using Ferrochrome Slag

This manuscript aims to utilize industrial wastes, i.e., ferrochrome slag (FS), ground granulated blast furnace slag, and fly ash to prepare alkali activated cementless controlled low strength material (CLSM). The physical properties, i.e., flowability, bleeding, unit weight, and mechanical properties such as strength, durability, and settlement were assessed for different CLSM mix designs and compared with cement-based FS-CLSM. The alkali activated FS-based CLSM achieved adequate flowability and unit weight with a strength value of 1.72 to 10.44 MPa for different CLSM mix propotions, with a California bearing ratio (CBR) value of 328% to make the CLSM mix a feasible pavement material. The study concludes that a high molar ratio of potassium hydroxide (KOH) accelerates the alkali activation process which helps in the formation of alkaline alumino/calcium silicate hydrates to bind the FS and produce CLSM with adequate strength. The high durability and low levels of toxic metals in the leachate cause the FS-based CLSM environment to be acceptable. Furthermore, life cycle analysis was carried out to investigate the effects of the FS-based CLSM on the ecosystem and human health.

Wave phenomena andthe high school AP physics classroom

Though a staple for modeling natural phenomena in much of modern science, oscillatory motion consists of at best 14% of any high school AP Physics exams focus and at most 6% in AP Physics 1. With such a minimal emphasis, wave phenomena can easily be quickly skipped over at the end of the school year for a typical AP Physics classroom rushing to wrap up before the exam in May. This presentation will share fun and simple ways to more fully incorporate major wave phenomena such as sound into an AP Physics curriculum, while supporting the College Board AP Physics units on Simple Harmonic Motion and Oscillations, with interactive demonstrations and hands-on activities. These demonstrations and activities provide for a deeper understanding of major curriculum ideas of oscillations as well as energy transfers in various systems, which the modern high school student can get excited about and easily relate to. With these small changes students have often reported this unit to be the most interesting and easily understood units of the year.

Descriptive analysis of post-stroke patients in a neurological physical therapy unit.

Physical therapy (PT) is the mainstay treatment in functional recovery after suffering a stroke. It is important in the acute phase of hospitalization after a stroke and later in the ambulatory phase. The present study aimed to analyze the data provided by the clinical history (CH) of people with stroke (pwS) who received PT treatment in order to establish a "preferential patient profile" (PPP) that may benefit more from an early PT treatment. This was an observational, descriptive, and cross-sectional study. A total of 137 pwS who had been treated with PT were selected. Information provided age, gender, stroke type and localization, and start and end dates of the different PT treatments. A descriptive analysis of the variables was conducted using absolute frequencies and percentages for the qualitative variables. Student's t-test or the Mann-Whitney U-test was used to determine the relationship between the time and variables "stroke type," "outpatient," and "occupational therapy." The Kruskal-Wallis H-test was applied for the "localization" variable. Of the entire sample, 57.7% were men, 65% had an ischemic stroke, and 48.9% had a stroke on the left side. The patients with hemorrhagic stroke had an increased number of hospital PT sessions (p = 0.01) and were younger (59.58 years) than patients with ischemic stroke (65.90 years) (p = 0.04). Our results do not show significant differences between the persons < 65 years and the number of outpatient physiotherapy sessions performed, although the resulting values are close to significance. Our results suggest that the PPP is a young person, with a hemorrhagic and left or bilateral stroke.

A review of methods to trace material flows into final products in dynamic material flow analysis: Comparative application of six methods to the United States and EXIOBASE3 regions, Part 2

Modeling pathways toward sustainable production and consumption requires improved spatio-temporal and material coverage of end-use product stocks. Momentarily, studies on inflow-driven, dynamic material flow analysis (dMFA) extrapolate scarce information on material end-use shares (i.e., ratios that split economy-wide material consumption to different end-use products) for single countries and years across longer time periods and global regions. Therefore, in part 1 of this work, we reviewed five methods to derive material end-use shares which use industry shipment data in physical units and monetary input–output tables (MIOTs). Herein, we comparatively apply these methods to the United States, drawing on detailed national data, as well as the multi-regional input–output model EXIOBASE3. To better match MIOT and dMFA system definitions, we propose the end-use transfer method, which re-routes specific intermediate outputs to final demand in MIOTs. In closing, we conclude on 12 points for improved end-use shares. We find mixed results regarding the fit between end-use shares derived from industry shipments and MIOTs: for detailed national data, we find good fit for some materials (e.g., aluminum), while others deviate strongly (e.g., steel). In many cases, the temporal trend of MIOT-derived end-use shares roughly agrees with industry shipments. For EXIOBASE3, we find good fit for some countries and materials, but substantial mismatches for others. Despite mixed results, combining MIOT-based end-use shares with industry shipments and auxiliary country-level data could enable improved temporal, geographical, and end-use resolution. However, the scarcity, documentation, and quality of input data are key limitations for more accurate and detailed end-use shares. This article met the requirements for a gold-gold data openness badge described at http://jie.click/badges.