Time Estimates Research Articles

Lithium-ion point-of-care ultrasound battery joint state of charge estimation

With recent advances in ultrasound technology, including accessibility and portability, point-of-care ultrasound systems (POCUS) are becoming ubiquitous in urban and rural health services. The efficient use of POCUS battery power is necessary due to the limited access to electricity in rural locations. Accurate estimation of the state-of-charge (SOC) of the onboard lithium-ion battery is crucial in ensuring the safe, efficient, and reliable operation of the battery management system (BMS). This research suggests a novel approach for striking a reasonable balance between the POCUS battery management systems computation time and SOC estimate accuracy. Given that the lithium-ion battery is a non-linear and time-varying system, it is modelled by a second-order RC equivalent circuit model (2-RC ECM). Real-time parametric identification is carried out using the method of recursive least squares with respect to an adaptive forgetting factor (AFFRLS). The joint SOC evaluation technique, ordering the results of real-time identification and the Extended Kalman Filter (EKF) recommended for estimating battery SOC at temperatures between 0 and 45 °C. Simulations were carried out using experimental data from the DST (Dynamic Stress Test), incremental current and, the Federal Urban Driving Program (FUDS) of the CALCE research group to evaluate the proposed approach. Based on the monitoring of dynamic changes in model parameters and the computational complexity of existing algorithms, the results reveal that the joint AFFRLS-EKF estimation proposed for the SOC strategy achieves good accuracy, high adaptability and rapid convergence of SOC estimation.

Debridement for surgical wounds.

Debridement for surgical wounds.

The Significance of Duration Weighted Neighborhood Effects for Violent Behavior and Explanation of Ethnoracial Differences

Abstract Purpose Two important issues constrain the neighborhood effects literature. First, most prior research examining neighborhood effects on aggression and self-reported violence uses a point in time (i.e., cross-sectional) estimate of neighborhood disadvantage even though the duration of exposure to neighborhood disadvantage varies between families. Second, neighborhood effects may be understated due to over-controlling for family socioeconomic conditions. Both limitations suggest that prior research may be underestimating neighborhood effects, which impacts research on the invariance thesis and explanation of ethnoracial differences. Methods The sample is drawn from the restricted use Future of Families and Child Well-being study. Data to measure youth’s exposure to neighborhood disadvantage is drawn from birth through age 9, with dependent variables measured at age 15. We estimate marginal structural models (MSM) with inverse probability of treatment weights (IPTW. Results The results support hypotheses, indicating that the duration weighted measure of neighborhood disadvantage is more strongly associated with aggression and self-reported violence than the point in time, and that it accounts for a larger share of the ethnoracial differences. Conclusions The findings provide a clear image of the consequences of long-term exposure to neighborhood disadvantage for aggression and violence. They suggest that criminologists addressing neighborhood effects should attempt, when feasible, to document and model the duration of exposure to neighborhood disadvantage. They are also consistent with and add to a growing literature addressing MSM modeling with IPTW weights.

Time estimates in prognostic discussions: A conversation analytic study of hospice multidisciplinary team meetings

Background: Recommendations state that multidisciplinary team expertise should be utilised for more accurate survival predictions. How the multidisciplinary team discusses prognoses during meetings and how they reference time, is yet to be explored. Aim: To explore how temporality is conveyed in relation to patients’ prognoses during hospice multidisciplinary team meetings. Design: Video-recordings of 24 hospice multidisciplinary team meetings were transcribed and analysed using Conversation Analysis. Setting/participants: A total of 65 staff participating in multidisciplinary team meetings in a UK hospice from May to December 2021. Results: Team members conveyed temporality in three different ways. (i) Staff stated that a patient was dying as part of the patient’s current health status. These formulations did not include a time reference per se but described the patient’s current situation (as dying) instead. (ii) Staff used specific time period references where another specific reference had been provided previously that somehow constrained the timeframe. In these cases, the prognosis would conflict with other proposed care plans. (iii) Staff members used unspecific time period references where the reference appeared vague and there was greater uncertainty about when the patient was expected to die. Conclusions: Unspecific time period references are sufficient for achieving meaningful prognostic talk in multidisciplinary teams. In-depth discussion and accurate prediction of patient prognoses are not deemed a priority nor a necessity of these meetings. Providing precise predictions may be too difficult due to uncertainty and accountability. The lack of staff pursuing more specific time references implies shared knowledge between staff and a context-specific use of prognostic estimates.

Evaluasi Penerapan Manajemen Waktu Dan Biaya Pada Proyek Pembagunan Puskesmas Jawakisa Kecamatan Aesesa Selatan Kabupaten Nagekeo

The construction of the Jawakisa Health Center is located in Tengatiba Village, South Aesesa District, Nagekeo Regency, in the implementation process did not meet the planned time, so the development project experienced delays. The purpose of this research is to evaluate the estimated costs and completion time for the construction of the project. This research uses quantitative methods by evaluated cost and time estimates for work that has been completed, and that has not been completed. The results of analysis using the value of results method are very effective in evaluating costs and time on the project. With the BCWS value for week 21 amounting to IDR 1,727,185,767.85, BCWP value for week 24 IDR 1,527,868,528.23, ACWP week 24 amounting to IDR 1,419,717,920.89, SV value – IDR 199,317.23, indicating the actual schedule is behind the planned schedule, CV value IDR 108,150.60, indicating the costs obtained is greater than the costs incurred, the SPI value for the 24th week is 0.88 indicating poor cost performance and wasteful compared to the planned schedule, the CPI value = 1.07 which means good and economical cost performance and shows the time needed for work that has not yet been completed. completed was 4.54 weeks while the total time to complete the entire project was 28.5 weeks and the estimated cost for the remaining work was Rp. 186,277,791.91 and the estimated total cost to complete all the work was Rp. early to optimize project results to the maximum.

Revisiting the Thornthwaite Mather procedure for baseflow and groundwater storage predictions in sloping and mountainous regions

Hillslope aquifers regulate streamflow and are a critical potable and irrigation water source, especially in developing countries. Knowing recharge and baseflow is essential for managing these aquifers. Methods using available data to calculate recharge and baseflow from aquifers are not valid for uplands. This paper adapts the Thornthwaite and Mather (T-M) procedure from plains to sloping and mountainous regions by replacing the linear reservoir with a zero-order aquifer. The revised T-M procedure was tested over four years in two contrasting watersheds in the humid Ethiopian highlands: the 57 km2 Dangishta with a perennial stream and the nine km2 Robit Bata, where the flow ceased four months after the end of the rain phase. The monthly average groundwater tables were predicted with an accuracy ranging from satisfactory to good for both watersheds. Baseflow predictions were “very good” after considering the evaporation from shallow groundwater in the valley bottom during the dry phase in Dangishta. We conclude that the T-M procedure is ideally suited for calculating recharge, baseflow and groundwater storage in upland regions with sparse hydrological data since the procedure uses as input only rainfall and potential evaporation data that are readily available together with an estimate of the aquifer travel time.

Insights into comparative genomics, structural features, and phylogenetic relationship of species from Eurasian Aster and its related genera (Asteraceae: Astereae) based on complete chloroplast genome.

Aster L. is an economically and phylogenetically important genus in the tribe Astereae. Here, the complete plastomes of the eight Aster species were assembled and characterized using next-generation sequencing datasets. The results indicated the complete plastomes of Aster had a quadripartite structure. These genomes were 152,045-152,729 bp in length and contained 132-133 genes, including 87 protein-coding genes, 37-38 tRNA genes, and eight rRNA genes. Expansion or contraction of inverted repeat regions and forward, palindromic, complement, and reverse repeats were detected in the eight Aster species. Additionally, our analyses showed the richest type of simple sequence repeats was A/T mononucleotides, and 14 highly variable regions were discovered by analyzing the border regions, sequence divergence, and hotspots. Phylogenetic analyses indicated that 27 species in Astereae were clustered into six clades, i.e., A to D, North American, and outgroup clades, and supported that the genera Heteropappus, Kalimeris, and Heteroplexis are nested within Aster. The results indicated the clades B to D might be considered as genera. Divergence time estimate showed the clades A, B, C, and D diverged at 23.15 Mya, 15.13 Mya, 24.29 Mya, and 21.66 Mya, respectively. These results shed light on the phylogenetic relationships of Aster and provided new information on species identification of Aster and its related genera.

Evaluating Diffusion Models for the Automation of Ultrasonic Nondestructive Evaluation Data Analysis

We develop decision support and automation for the task of ultrasonic non-destructive evaluation data analysis. First, we develop a probabilistic model for the task and then implement the model as a series of neural networks based on Conditional Score-Based Diffusion and Denoising Diffusion Probabilistic Model architectures. We use the neural networks to generate estimates for peak amplitude response time of flight and perform a series of tests probing their behavior, capacity, and characteristics in terms of the probabilistic model. We train the neural networks on a series of datasets constructed from ultrasonic non-destructive evaluation data acquired during an inspection at a nuclear power generation facility. We modulate the partition classifying nominal and anomalous data in the dataset and observe that the probabilistic model predicts trends in neural network model performance, thereby demonstrating a principled basis for explainability. We improve on previous related work as our methods are self-supervised and require no data annotation or pre-processing, and we train on a per-dataset basis, meaning we do not rely on out-of-distribution generalization. The capacity of the probabilistic model to predict trends in neural network performance, as well as the quality of the estimates sampled from the neural networks, support the development of a technical justification for usage of the method in safety-critical contexts such as nuclear applications. The method may provide a basis or template for extension into similar non-destructive evaluation tasks in other industrial contexts.

Lower bounds for the rank of a matrix with zeros and ones outside the leading diagonal

We have found a lower bound on the rank of a square matrix, where every entry in the leading diagonal is neither zero nor one, but every entry outside the leading diagonal is either zero or one. The rank of such a matrix is at least half the order of the matrix. Under an additional condition, the lower bound is one higher. This condition means that some auxiliary system of linear equations has no binary solution. Examples are given showing the achievability of the lower bound. This lower bound on the rank allows us to reduce the problem of finding a binary solution to a system of linear equations, where the number of linearly independent equations is sufficiently large, to a similar problem in a smaller number of variables. Restrictions on the existence of a large set of solutions are found, each of which differs from binary one by the value of one variable. In addition, we discuss the possibility of certifying the absence of a binary solution to a system of a large set of linear algebraic equations. Estimates of the running time for calculating the rank of a matrix with the SymPy computer algebra system are also given. It is shown that the matrix rank over the field of residues modulo a prime number is calculated in less time than is usually required to calculate the rank of a matrix of the same order over the field of rational numbers.

Do weighted blankets improve sleep among children with a history of maltreatment? A randomized controlled crossover trial.

Sleep disruption is prevalent and persistent among children who experience maltreatment/interpersonal trauma. Weighted blankets have gained popularity in recent years as a potential nonpharmacological intervention for improving sleep in various populations, but their efficacy has not been examined among maltreated children. The current study used a randomized, within-subjects, crossover design to examine whether the use of a weighted blanket improves objective and/or subjective indices of sleep among 30 children, ages 6-15 years (mean = 9.7, standard deviation = 2.9) adopted from foster care. Participants used a weighted blanket for 2 weeks and their usual (unweighted) blanket for 2 weeks in a counterbalanced order. Sleep outcomes were measured using actigraphy and subjective sleep diaries. No differences in actigraphy-based or subjective estimates of total sleep time, sleep onset latency, wake after sleep onset, or sleep quality ratings were found based on blanket type. Child age, biological sex, timing of participation (school year vs summer months), and maltreatment/trauma history did not impact outcomes. Although we did not find evidence that weighted blankets improve sleep among children with a history of maltreatment/interpersonal trauma, additional well-controlled studies using larger samples of children are needed. Cifre AB, Vieira A, Baker C, etal. Do weighted blankets improve sleep among children with a history of maltreatment? A randomized controlled crossover trial. J Clin Sleep Med. 2024;20(9):1405-1413.

Herbarium data accurately predict the timing and duration of population‐level flowering displays

Forecasting the impacts of changing climate on the phenology of plant populations is essential for anticipating and managing potential ecological disruptions to biotic communities. Herbarium specimens enable assessments of plant phenology across broad spatiotemporal scales. However, specimens are collected opportunistically, and it is unclear whether their collection dates – used as proxies of phenological stages – are closest to the onset, peak, or termination of a phenophase, or whether sampled individuals represent early, average, or late occurrences in their populations. Despite this, no studies have assessed whether these uncertainties limit the utility of herbarium specimens for estimating the onset and termination of a phenophase. Using simulated data mimicking such uncertainties, we evaluated the accuracy with which the onset and termination of population‐level phenological displays (in this case, of flowering) can be predicted from natural‐history collections data (controlling for biases in collector behavior), and how the duration, variability, and responsiveness to climate of the flowering period of a species and temporal collection biases influence model accuracy. Estimates of population‐level onset and termination were highly accurate for a wide range of simulated species' attributes, but accuracy declined among species with longer individual‐level flowering duration and when there were temporal biases in sample collection, as is common among the earliest and latest‐flowering species. The amount of data required to model population‐level phenological displays is not impractical to obtain; model accuracy declined by less than 1 day as sample sizes rose from 300 to 1000 specimens. Our analyses of simulated data indicate that, absent pervasive biases in collection and if the climate conditions that affect phenological timing are correctly identified, specimen data can predict the onset, termination, and duration of a population's flowering period with similar accuracy to estimates of median flowering time that are commonplace in the literature.

Geographical accessibility to functional emergency obstetric care facilities in urban Nigeria using closer-to-reality travel time estimates: a population-based spatial analysis

Better accessibility for emergency obstetric care facilities can substantially reduce maternal and perinatal deaths. However, pregnant women and girls living in urban settings face additional complex challenges travelling to facilities. We aimed to assess the geographical accessibility of the three nearest functional public and private comprehensive emergency obstetric care facilities in the 15 largest Nigerian cities via a novel approach that uses closer-to-reality travel time estimates than traditional model-based approaches. In this population-based spatial analysis, we mapped city boundaries, verified and geocoded functional comprehensive emergency obstetric care facilities, and mapped the population distribution for girls and women aged 15-49 years (ie, of childbearing age). We used the Google Maps Platform's internal Directions Application Programming Interface to derive driving times to public and private facilities. Median travel time and the percentage of women aged 15-49 years able to reach care were summarised for eight traffic scenarios (peak and non-peak hours on weekdays and weekends) by city and within city under different travel time thresholds (≤15 min, ≤30 min, ≤60 min). As of 2022, there were 11·5 million girls and women aged 15-49 years living in the 15 studied cities, and we identified the location and functionality of 2020 comprehensive emergency obstetric care facilities. City-level median travel time to the nearest comprehensive emergency obstetric care facility ranged from 18 min in Maiduguri to 46 min in Kaduna. Median travel time varied by location within a city. The between-ward IQR of median travel time to the nearest public comprehensive emergency obstetric care varied from the narrowest in Maiduguri (10 min) to the widest in Benin City (41 min). Informal settlements and peripheral areas tended to be worse off compared to the inner city. The percentages of girls and women aged 15-49 years within 60 min of their nearest public comprehensive emergency obstetric care ranged from 83% in Aba to 100% in Maiduguri, while the percentage within 30 min ranged from 33% in Aba to over 95% in Ilorin and Maiduguri. During peak traffic times, the median number of public comprehensive emergency obstetric care facilities reachable by women aged 15-49 years under 30 min was zero in eight (53%) of 15 cities. Better access to comprehensive emergency obstetric care is needed in Nigerian cities and solutions need to be tailored to context. The innovative approach used in this study provides more context-specific, finer, and policy-relevant evidence to support targeted efforts aimed at improving comprehensive emergency obstetric care geographical accessibility in urban Africa. Google.

Design and economic implications of using steel fibers in elevated slabs of multi‐story buildings

AbstractThis paper presents a comprehensive comparison between conventional reinforced concrete (RC) and steel fiber‐reinforced concrete (SFRC) slabs. Twenty‐two‐way rectangular RC and SFRC slabs are designed with varying dimensions, aspect ratios, and boundary conditions, following verified international standards to compare the steel quantities in a unique study. SFRC slabs with larger aspect ratios and discontinuous edges required significantly higher steel percentages than square slabs, as the random three‐dimensional distribution of steel fibers suited the load distribution pattern of square slabs. To further conduct a detailed design and economic feasibility case study on a realistic building model, two 12‐story buildings are computationally designed with RC and SFRC alternatives. The results indicate that SFRC slabs required approximately 25% more steel than RC slabs due to the uniform distribution of steel fibers throughout the section. Project cost and time estimates were conducted based on standard productivity manuals and cost databases in two distinct economies, India and the USA. Despite the higher steel requirements, the 12‐story SFRC building showed time savings of 34.1 days (5.44%) and cost savings of 4.88% and 1.27% when constructed in the USA and India, respectively. The results are compared with limited available data in literature. In conclusion, the study suggests that SFRC slabs in multi‐story buildings could be more economically favorable in countries with higher labor costs.

Fossil-calibrated molecular clock data enable reconstruction of steps leading to differentiated multicellularity and anisogamy in the Volvocine algae.

Throughout its nearly four-billion-year history, life has undergone evolutionary transitions in which simpler subunits have become integrated to form a more complex whole. Many of these transitions opened the door to innovations that resulted in increased biodiversity and/or organismal efficiency. The evolution of multicellularity from unicellular forms represents one such transition, one that paved the way for cellular differentiation, including differentiation of male and female gametes. A useful model for studying the evolution of multicellularity and cellular differentiation is the volvocine algae, a clade of freshwater green algae whose members range from unicellular to colonial, from undifferentiated to completely differentiated, and whose gamete types can be isogamous, anisogamous, or oogamous. To better understand how multicellularity, differentiation, and gametes evolved in this group, we used comparative genomics and fossil data to establish a geologically calibrated roadmap of when these innovations occurred. Our ancestral-state reconstructions, show that multicellularity arose independently twice in the volvocine algae. Our chronograms indicate multicellularity evolved during the Carboniferous-Triassic periods in Goniaceae + Volvocaceae, and possibly as early as the Cretaceous in Tetrabaenaceae. Using divergence time estimates we inferred when, and in what order, specific developmental changes occurred that led to differentiated multicellularity and oogamy. We find that in the volvocine algae the temporal sequence of developmental changes leading to differentiated multicellularity is much as proposed by David Kirk, and that multicellularity is correlated with the acquisition of anisogamy and oogamy. Lastly, morphological, molecular, and divergence time data suggest the possibility of cryptic species in Tetrabaenaceae. Large molecular datasets and robust phylogenetic methods are bringing the evolutionary history of the volvocine algae more sharply into focus. Mounting evidence suggests that extant species in this group are the result of two independent origins of multicellularity and multiple independent origins of cell differentiation. Also, the origin of the Tetrabaenaceae-Goniaceae-Volvocaceae clade may be much older than previously thought. Finally, the possibility of cryptic species in the Tetrabaenaceae provides an exciting opportunity to study the recent divergence of lineages adapted to live in very different thermal environments.

Blocked versus interleaved: How range contexts modulate time perception and its EEG signatures.

Accurate time perception is a crucial element in a wide range of cognitive tasks, including decision-making, memory, and motor control. One commonly observed phenomenon is that when given a range of time intervals to consider, people's estimates often cluster around the midpoint of those intervals. Previous studies have suggested that the range of these intervals can also influence our judgments, but the neural mechanisms behind this "range effect" are not yet understood. We used both behavioral tests and electroencephalographic (EEG) measures to understand how the range of sample time intervals affects the accuracy of people's subsequent time estimates. Study participants were exposed to two different setups: In the "blocked-range" (BR) session, short and long intervals were presented in separate blocks, whereas in the "interleaved-range" (IR) session, intervals of various lengths were presented randomly. Our findings indicated that the BR context led to more accurate time estimates compared to the IR context. In terms of EEG data, the BR context resulted in quicker buildup of contingent negative variation (CNV), which also reached higher amplitude levels and dissolved more rapidly during the encoding stage. We also observed an enhanced amplitude in the offset P2 component of the EEG signal. Overall, our results suggest that the variability in time intervals, as defined by their range, influences the neural processes that underlie time estimation.

Evidence that Eddington ratio depends upon a supermassive black hole's mass and redshift: Implications for radiative efficiency

Abstract Presently, it is unclear whether the Eddington ratio (λ) and radiative efficiency (ε) depend on a supermassive black hole's (SMBH's) redshift z and mass MBH. We attempt to resolve this issue using published data for 132,000 SMBHs with MBH ≥107 Msun (solar masses) at ∼ 0.1< z <2.4 covering ∼10 billion years of cosmic time, with MBH determined using Mg-II lines and bolometric luminosities Lbol based on a weighted mean of Lbol from 2 or more monochromatic luminosities and a single uniformly applied correction factor. The SMBHs are sorted into 7 MBH bins separated from each other by half an order of magnitude. The λ and z data in each bin are subjected to spline regression analysis. The results unambiguously show that for similar-size SMBHs, λ decreases as z decreases and that for a given redshift, larger SMBHs have a lower λ. These findings require that either a SMBH's accretion rate and/or its radiative efficiency be a function of z and MBH and, in the context of the Bondi accretion model, imply that radiative efficiency is an inverse function of z and MBH. These findings suggest that SMBHs become less efficient (higher ε) in accreting gases as the ambient gas density decreases with z and that larger SMBHs are more efficient (lower ε) than smaller ones. The results leave little doubt that the current widespread practice of assigning ε a standard value is untenable and gives erroneous estimates of accretion rates and growth times of SMBHs.

Long-term Performance of Textured HDPE Geomembranes in Municipal Solid Waste Landfills

The effect of texturing (co-extrusion using a blowing agent) on the long-term performance of geomembranes immersed in synthetic municipal solid waste (MSW) leachate is examined over an approximately 8-year period. Antioxidant depletion of the textured part is shown to be much faster than that of the smooth edge. Likewise, the degradation in the tensile break properties at 85°C is faster for the textured part than for the smooth edge portion and smooth equivalent. The updated estimates for antioxidant depletion time based on data at four different temperatures (40, 55, 75, and 85°C) over 98 months of data collection are compared with predictions based on 34 months of data and the implications are discussed. Nominal failure was reached at 75°C, and this combined with data at 85°C allows prediction of the time between depletion of Std-OIT and nominal failure at lower temperatures. The effect of salt concentration in incubation fluid on the time to degradation is examined. Finally, the paper comments on the uses of textured versus smooth geomembrane.

Denoising Seismic Waveforms Using a Wavelet-Transform-Based Machine-Learning Method

ABSTRACT Seismic waveform data recorded at stations can be thought of as a superposition of the signal from a source of interest and noise from other sources. Frequency-based filtering methods for waveform denoising do not result in desired outcomes when the targeted signal and noise occupy similar frequency bands. Recently, denoising techniques based on deep-learning convolutional neural networks (CNNs), in which a recorded waveform is decomposed into signal and noise components, have led to improved results. These CNN methods, which use short-time Fourier transform representations of the time series, provide signal and noise masks for the input waveform. These masks are used to create denoised signal and designaled noise waveforms, respectively. However, advancements in the field of image denoising have shown the benefits of incorporating discrete wavelet transforms (DWTs) into CNN architectures to create multilevel wavelet CNN (MWCNN) models. The MWCNN model preserves the details of the input due to the good time–frequency localization of the DWT. Here, we use a data set of over 382,000 constructed seismograms recorded by the University of Utah Seismograph Stations network to compare the performance of CNN and MWCNN-based denoising models. Evaluation of both models on constructed test data shows that the MWCNN model outperforms the CNN model in the ability to recover the ground-truth signal component in terms of both waveform similarity and preservation of amplitude information. Model evaluation of real-world data shows that both the CNN and MWCNN models outperform standard band-pass filtering (BPF; average improvement in signal-to-noise ratio of 9.6 and 19.7 dB, respectively, with respect to BPF). Evaluation of continuous data suggests the MWCNN denoiser can improve both signal detection capabilities and phase arrival time estimates.

ASSESSMENT OF THE EFFICIENCY OF FIRE EXTINGUISHING SYSTEMS

As previously shown, many indicators characterise the quality of fire extinguishing systems. The most common quality indicator is fire extinguishing time. For fire extinguishing systems focused on extinguishing Class B fires using sprayed water, the authors have constructed a transcendental equation, the root of which is the fire extinguishing time. We derived the equation provided that the intensity of the sprayed water supply to the combustion centre to be described by the Heaviside function. The dynamic properties of fire are defined using the integral Laplace transform. We obtained the functional dependence of class B fire extinguishing time on fire parameters and showed that this time does not exceed a tenth of the constant fire time. In the first approximation, the inertial properties of the fire extinguishing system can be taken into account by the transfer function of an aperiodic link with a generalised time constant. For this case, we constructed a transcendental equation that determines the fire extinguishing time by the inertial fire extinguishing system. We note that, according to inertial properties, fire extinguishing systems fall into three classes. For each of the three classes, estimates of the extinguishing time of a class B fire were obtained, depending on the dynamic properties of this fire. The results show that this time can change several times. The authors have introduced the criterion for the efficiency of fire extinguishing systems, which characterises the degree of approximation of the speed of the fire extinguishing system to the maximum possible value. This criterion also indicates how much it is necessary to increase the extinguishing agent mass supplied per unit area of the fire relative to the extinguishing agent mass supplied in leaps per unit area of the fire, provided that the extinguishing times are the same. We obtained estimates of the effectiveness of fire extinguishing systems using this criterion. Furthermore, we provided recommendations on the use of the efficiency criterion. Keywords: fire extinguishing system, extinguishing time, efficiency criterion.

Careworn: The Economic History of Caring Labor

Economists ignore caring labor since most is provided unpaid. Disregard is unjust, theoretically indefensible, and probably misleading. Valuation requires estimates of time spent and the replacement or opportunity costs of that time. I use the maintenance costs of British workers, costs which cover both the material inputs into upkeep and the domestic services needed to turn commodities into livings, to isolate the costs of paid domestic labor. I then impute the value of unpaid domestic labor from these market equivalents, and aggregate across households without domestic servants. Historically, unpaid domestic labor represented c. 20 percent of total income, a contribution that suggests the need to revise some standard narratives.