Production Threshold Research Articles

Factors driving antimony accumulation in soil-pakchoi and wheat agroecosystems: Insights and predictive models

The accumulation of antimony (Sb) in plants and its potential effects on human health are of increasing concern. Nevertheless, only a few countries or regions have established soil Sb thresholds for agricultural purposes, and soil properties have not been taken into account. This study investigated the accumulation of Sb in the edible parts of pakchoi and wheat grain by adding exogenous Sb to 21 soils with varying properties. The results revealed a positive correlation between bioavailable Sb (Sbava, extracted by 0.1 M K2HPO4) in soil and Sb in the edible parts of pakchoi (R2 = 0.77, p < 0.05) and wheat grain (R2 = 0.54, p < 0.05). Both machine learning and traditional multiple regression analysis indicated Sbava was the most critical feature and the main soil properties that contributed to Sb uptake by pakchoi and wheat were CaCO3 and clay, respectively. The advisory food limits for Sb in pakchoi and wheat were estimated based on health risk assessment, and used to derive soil thresholds for safe pakchoi and wheat production based on Sbtot and Sbava, respectively. These findings hold potential for predicting Sb uptake by crops with different soil properties and informing safe production management strategies.

The impact of willingness-to-pay threshold on price reduction recommendations for oncology drugs: a review of assessments conducted by the Canadian Agency for Drugs and Technologies in Health.

Since late 2020, the Canadian Agency of Drugs and Technologies in Health (CADTH) has been using a threshold of $50,000(CAD)per quality-adjusted life-year (QALY) for both oncology and non-oncology drugs. When used for oncology products, this threshold is hypothesized to have a higher impact on the time to access these drugs in Canada. We studied the impact of price reductions on time to engagement and negotiation with the pan-Canadian Pharmaceutical Alliance for oncology drugs reviewed by CADTH between January 2020 and December 2022. Overall, 103 assessments reported data on price reductions recommended by CADTH to meet the cost-effectiveness threshold for reimbursement. Of these assessments, 57% (59/103) recommendations included a price reduction of greater than 70% off the list price. Eight percent (8/103) were not cost-effective even at a 100% price reduction. Of the 47 assessments that had a clear benefit, in 21 (45%) CADTH recommended a price reduction of at least 70%. The median time to price negotiation (not including time to engagement) for assessments that received at least 70% vs >70% price reduction was 2.6vs 4.8months. This study showed that there is a divergence between drug sponsor's incremental cost-effectiveness ratio (ICER) and CADTH revised ICER leading to a price reduction to meet the $50,000/QALY threshold. For the submissions with clear clinical benefit the median length of engagement (2.5 vs 3.3months) and median length of negotiation (3.1 vs 3.6months) were slightly shorter compared with the submissions where uncertainties were noted in the clinical benefit according to CADTH. This study shows that using a $50,000 per QALY threshold for oncology products potentially impacts timely access to life saving medications.

Phosphorus applications adjusted to optimal crop yields can help sustain global phosphorus reserves

With the longevity of phosphorus reserves uncertain, distributing phosphorus to meet food production needs is a global challenge. Here we match plant-available soil Olsen phosphorus concentrations to thresholds for optimal productivity of improved grassland and 28 of the world’s most widely grown and valuable crops. We find more land (73%) below optimal production thresholds than above. We calculate that an initial capital application of 56,954 kt could boost soil Olsen phosphorus to their threshold concentrations and that 28,067 kt yr−1 (17,500 kt yr−1 to cropland) could maintain these thresholds. Without additional reserves becoming available, it would take 454 years at the current rate of application (20,500 kt yr−1) to exhaust estimated reserves (2020 value), compared with 531 years at our estimated maintenance rate and 469 years if phosphorus deficits were alleviated. More judicious use of phosphorus fertilizers to account for soil Olsen phosphorus can help achieve optimal production without accelerating the depletion of phosphorus reserves.

Constructing and Disseminating Urban Cultural Tourism Media Image through Short Videos

With the widespread adoption of mobile internet and the rise of short video platforms, the modes of information dissemination are undergoing profound changes. As an emerging content format, short videos, characterized by their intuitiveness, vividness, and fragmented nature, have rapidly occupied a significant amount of user time. This is particularly true for the construction and dissemination of urban cultural tourism media images, where short videos have become an indispensable tool. Urban cultural tourism media images refer to the representation of a city’s culture and tourism through various media means, playing a crucial role in the city’s development and reputation. However, traditional methods of disseminating cultural tourism images have evident shortcomings. With the emergence of short videos, new opportunities have arisen for the construction and dissemination of urban cultural tourism media images. The relatively low production threshold of short videos allows cities to showcase their cultural and tourism resources through various creative means, attracting more visitors and gradually enhancing the city’s competitiveness and local economic development.

Behavior of Amagmatic Orogenic Geothermal Systems: Insights From the Agua Blanca Fault, Baja California, Mexico

AbstractAmagmatic geothermal systems within regional‐scale orogenic faults are promising renewable resources for heat and possibly electricity production. However, their behavior needs to be better understood to improve their exploration and assessment of energy potential. To provide more insight, we report geochemical, geological, and geophysical studies from seven hot spring sites strung along a 90 km segment of the Agua Blanca Fault, which traverses a mountainous region of northern Baja California, Mexico. Our results show that topographic heads drive infiltration of meteoric water deep into basement rocks, where it is heated according to the local geothermal gradients. Long paths lead to long water residence times and high 3He/Hetotal fractions. The hot water ascends along preferentially permeable zones within the ABF, discharging at temperatures from 37°C in inland springs to 102°C on the Pacific coast. Higher discharge temperatures correlate positively with the degree of extensional fault displacement (a proxy for fault permeability). Correlations between hydraulic head gradients, residence times, and 3He/Hetotal of the thermal waters show that the hydraulic head gradient controls the length and depth of the flow paths, whereas the magnitudes and locations of the discharge sites are controlled by fault permeability. Optimal conditions at the coast allow the 120°C temperature threshold for electricity production to be reached at relatively shallow depths (&lt;2 km), demonstrating the potential of orogenic geothermal systems not only for exploitation of hot discharging water but also for EGS exploitation of the hot rocks that surround the water upflow zones.

Estimates of differential toxin expression governing heterogeneous intracellular lifespans of Streptococcus pneumoniae.

Following invasion of the host cell, pore-forming toxins secreted by pathogens compromise vacuole integrity and expose the microbe to diverse intracellular defence mechanisms. However, the quantitative correlation between toxin expression levels and consequent pore dynamics, fostering the intracellular life of pathogens, remains largely unexplored. In this study, using Streptococcus pneumoniae and its secreted pore-forming toxin pneumolysin (Ply) as a model system, we explored various facets of host-pathogen interactions in the host cytosol. Using time-lapse fluorescence imaging, we monitored pore formation dynamics and lifespans of different pneumococcal subpopulations inside host cells. Based on experimental histograms of various event timescales such as pore formation time, vacuolar death or cytosolic escape time and total degradation time, we developed a mathematical model based on first-passage processes that could correlate the event timescales to intravacuolar toxin accumulation. This allowed us to estimate Ply production rate, burst size and threshold Ply quantities that trigger these outcomes. Collectively, we present a general method that illustrates a correlation between toxin expression levels and pore dynamics, dictating intracellular lifespans of pathogens.

A breast milk production model for achieving exclusive breastfeeding in low-risk primiparas who had vaginal births at 4 months postpartum: A prospective cohort study.

This study aimed to investigate the thresholds of milk production for predicting the achievement of exclusive breastfeeding (EBF) at 4 months postpartum. The inclusion criteria were singleton, low-risk primiparas, non-cesarean section, and healthy mothers and infants. Temporary feeding of artificial milk in the past was included. Women who could be judged to have intentionally used artificial milk were excluded from the analysis. Measurements of the 24-h milk production by test weights were obtained at early postpartum (days 3-4) and at 1 month postpartum. To predict the achievement of EBF at 4 months postpartum, the area under the receiver operating characteristic (ROC) curve was calculated for early postpartum and 1 month milk production. There were 80 eligible participants analyzed. ROC analysis of milk production for achieving EBF at 4 months revealed an area under the curve (AUC) of 0.736 (95% CI: [0.625, 0.848]) for early postpartum and an AUC of 0.854 (95% CI: [0.772, 0.936]) for 1 month postpartum. The proposed thresholds are 102 g/day (higher sensitivity) and 161 g/day (higher specificity) at early postpartum, and 527 g/day (higher sensitivity) at 1 month postpartum. In low-risk primiparas, the milk production models at early postpartum and 1 month postpartum showed a high accuracy for predicting the achievement of EBF at 4 months postpartum. The present study indicates that even when formula milk is temporarily used, it is still possible to reach the goal of achieving EBF.

Hyperon production and interaction studies in protonproton scattering with HADES

Hyperons and their interactions with baryonic matter may play a key role in our understanding of the core of neutron stars. Moreover, the internal structure of hyperons and their excitations are of great interest. Their structure can be probed by exploiting their couplings to radiative probes such as by measuring electromagnetic transition form factors. HADES (High-Acceptance Di-Electron Spectrometer) at GSI collected high-statistics proton-proton scattering data in 2022 at √s = 3.48 GeV. The Λ - Λ interaction is currently being studied in this data along with production of Σ states where the Dalitz decay of hyperons might be observed for the first time. In addition, the reaction pp → pK+K+Ξ−[π−Λ[pπ−]] has been studied to probe the production mechanism of double strangeness near its production threshold. This proceeding addresses the hyperon physics case and discusses the ongoing Ξ− analysis. A preliminary upper limit for the cross section at √s = 3.48 GeV is presented taking into account only statistical uncertainties.

Assessment of DP Threshold and its Test–Retest Reliability in Normal Hearing Individuals

Purpose: Distortion Product (DP) threshold test has been recently introduced as a clinical tool that provides frequency specific quantitative information on hearing sensitivity in dB HL. However, due to the dearth of literature in determining its degree of reliability, the extent of confidence in the test results has not been estimated. Therefore, the present study aimed at establishing the normative of DP threshold values across test frequencies in normal hearing individuals and check for its test-retest reliability.Methods: Purposive sampling was utilized in the study wherein fifty normal hearing individuals in the age range of 18 to 30 years (x̅=24, σ=2.1) were considered. DP threshold test was carried out across test frequencies from 1 kHz to 8 kHz in measurement window of 50 dB HL and was re-examined after 15 days.Results: The range of DP threshold level was -5 to 20 dB HL in right ear and -5 to 25 dB HL in left ear across the test frequencies. It was found to have the mean difference ranging -0.02 to 1.06 dB HL across test frequencies between the two sessions. Non-parametric Wilcoxon Signed Ranks test was performed to assess test-retest reliability which revealed no statistically significant difference for both ears (&lt;i&gt;p&lt;/i&gt;&gt;0.05).Conclusions: Hence, the current study presents normative of DP threshold test along with variance, beyond which the fluctuations in outer hair cell functioning can be expected to have occurred. Moreover, it is found to have good test retest reliability between the two sessions suggesting good potentiality of the test in assessing outer hair cells functioning.

Impact of firefighter hood design on range of motion, noise production and hearing

Firefighter hoods must provide protection from elevated temperatures and products of combustion while simultaneously being comfortable and limiting interference with firefighting movement or completion of fireground activities. This study was to quantify the impact of hood design (traditional knit hood vs. several models of particulate-blocking hoods) on wearability measures such as range of motion, noise production and hearing threshold. Firefighters’ perceptions of wearability were also collected. In a controlled laboratory environment, 24 firefighters performed movement and hearing tests. Wearing particulate-blocking hoods resulted in decreased rotational range of motion, and thicker hoods reduced hearing ability. Design, but not necessarily the number of layers, affected noise production by the hood during head movement. Practitioner summary: Particulate-blocking hoods resulted in reduced rotational range of motion relative to the traditional design and the no-hood condition. Hoods with additional layers resulted in decreased hearing ability. Noise production was increased in designs of particulate-blocking hoods with a membrane-based blocking layer independent of the number of layers.

Leptonic Model for Neutrino Emission from Active Galactic Nuclei.

It is often stated that the observation of high-energy neutrinos from an astrophysical source would constitute indisputable proof for the acceleration of hadronic cosmic rays. Here, we point out that there exists a purely leptonic mechanism to produce TeV-scale neutrinos in astrophysical environments. In particular, very high-energy synchrotron photons can scatter with x rays, exceeding the threshold for muon-antimuon pair production. When these muons decay, they produce neutrinos without any cosmic-ray protons or nuclei being involved. In order for this mechanism to be efficient, the source in question must produce very high-energy photons which interact in an environment that is dominated by keV-scale radiation. We find that such a source could potentially generate an observable neutrino flux through muon pair production for reasonable choices of physical parameters.

Thallium content in vegetables and derivation of threshold for safe food production in soil: A meta-analysis

Soil thallium (Tl) pollution is a serious environmental problem, and vegetables are the primary pathway for human exposure to Tl. Therefore, it is important to investigate the characteristics of soil Tl uptake by vegetables. In this study, the meta-analysis approach was first applied to explore the relationship between Tl content in vegetables and soil environment, as well as key factors influencing soil physical–chemical properties, and to derive soil thresholds for Tl. The results indicated that various types of vegetables have different capabilities for Tl accumulation. Vegetables from contaminated areas showed high Tl accumulation, and the geomean Tl content in different types of vegetables was in the following order: leafy > root–stalk > solanaceous vegetables. Taro and kale had significantly higher capability to accumulate soil Tl among the 35 species studied, with Tl bioconcentration factor values of 0.060 and 0.133, respectively. Pearson correlation analysis and meta-analysis revealed that the Tl content in vegetables was significantly correlated with soil pH and Tl content in soil. The linear predictive model for Tl accumulation in vegetables based on soil Tl content described the data well, and the fitting coefficient R2 increased with soil pH value. According to potential dietary toxicity, the derived soil Tl thresholds for all, leafy and root–stalk vegetables increased with an increase in soil pH, and were in the range of 1.46–6.72, 1.74–5.26 and 0.92–6.06 mg/kg, respectively. The soil Tl thresholds for kale, lettuce and carrot were in the range of 0.24–4.89, 2.94–3.32 and 3.77–14.43 mg/kg, respectively. Ingestion of kale, beet, sweet potato, potato, taro, pepper, turnip, Chinese cabbage, eggplant and carrot poses potential health risks. The study provides scientific guidance for vegetable production in Tl-contaminated areas and can help with the selection of vegetable species suitable for avoiding the absorption of Tl from contaminated soil.

Delbrück Scattering above the Pair Production Threshold: Going beyond the Born Approximation

AbstractA theoretical method to calculate Delbrück scattering amplitudes for photon energies above the electron‐positron () pair production threshold is presented. The method is based on the application of the relativistic Dirac–Coulomb Green function and describes the interaction of the virtual pair with the Coulomb field of a target to all orders in the coupling strength parameter . To illustrate the application of the developed approach, detailed calculations have been performed for the scattering of 2.754 MeV photons off bare ions with a wide range of nuclear charge numbers. Results of these calculations clearly indicate that the higher‐order terms beyond the Born approximation lead to a strong enhancement of the imaginary part of the Delbrück amplitude and have to be taken into account for the analysis and guidance of gamma‐ray scattering experiments.

Planetary entropy production as a thermodynamic constraint for exoplanet habitability

ABSTRACT Any biosphere emerges, lives, and grows producing entropy. Entropy production is a thermodynamic function crucial in the framework of non-equilibrium thermodynamics as it is directly related to the dynamical behaviour of far-from equilibrium systems. The extent of entropy production is proportional to the ability of such systems to dissipate free energy and thus to ‘live’, to evolve, to grow in complexity. Generally, a certain threshold of entropy production must be exceeded for the emergence of complex self-organizing structures. Thus, the entropy production can be considered as the thermodynamic thrust that drives life emergence and evolution. In this perspective, we propose that the value of the planetary entropy production (PEP) can provide a first order estimate of the thermodynamic potential of planetary environment to sustain a complex biosphere. Here we use a simplified approach to evaluate the upper limit to the PEP and to the corresponding free energy as function of stellar temperature and orbital parameters of the planet. We found that only Earth-like planets in the circumstellar habitable zone (CHZ) of G and F stars can have a PEP value higher than the Earth value. Further significant thermodynamic differences exist between the inner and outer edge of the CHZ, with the inner edge being thermodynamically more advantageous for the development of complex biospheres. Interestingly, among the recently proposed habitable exoplanets, the ones belonging to the Hycean planets appear the thermodynamically best candidates.

The threshold of rule productivity in infants.

Most learning theories agree that the productivity of a rule or a pattern relies on regular exemplars being dominant over exceptions; the threshold for productivity is, however, unclear; moreover, gradient productivity levels are assumed for different rules/patterns, regular or irregular. One theory by Yang, the Tolerance Principle (TP), specified a productivity threshold applicable to all rules, calculated by the numbers of total exemplars and exceptions of a rule; furthermore, rules are viewed as quantal, either productive or unproductive, with no gradient levels. We evaluated the threshold and gradience-quantalness questions by investigating infants' generalization. In an implicit learning task, 14-month-olds heard exemplars of an artificial word-order rule and exceptions; their distributions were set closed to the TP-threshold (5.77) on both sides: 11 regular exemplars vs. 5 exceptions in Condition 1 (productiveness predicted), and 10 regular exemplars vs. 6 exceptions in Condition 2 (unproductiveness predicted). These predictions were pitted against those of the statistical majority threshold (50%), a common assumption which would predict generalization in both conditions (68.75, 62.5%). Infants were tested on the trained rule with new exemplars. Results revealed generalization in Condition 1, but not in Condition 2, supporting the TP-threshold, not the statistical majority threshold. Gradience-quantalness was assessed by combined analyses of Conditions 1-2 and previous experiments by Koulaguina and Shi. The training across the conditions contained gradually decreasing regular exemplars (100, 80, 68.75, 62.5, 50%) relative to exceptions. Results of test trials showed evidence for quantalness in infants (productive: 100, 80, 68.75%; unproductive: 62.5, 50%), with no gradient levels of productivity.

Next-to-leading power resummed rapidity distributions near threshold for Drell-Yan and diphoton production

We consider Drell-Yan production and QCD-induced diphoton production and compute their rapidity distributions up to next-to-leading power (NLP) in the threshold variable. We give results for rapidity distributions of the Drell-Yan process up to NNLO accuracy and show that a factorised structure occurs for the leading logarithms (LL) at NLP, generalising the result at leading power. For diphoton production, we generalise methods based on kinematical shifts to find the NLO cross section up to NLP for rapidity distributions. From the results for these two processes, we derive resummed cross sections at NLP LL accuracy that are double differential in the threshold variable and the rapidity variable, which generalise results for single differential resummed cross sections.

An improved random forest based on the classification accuracy and correlation measurement of decision trees

Random forest is one of the most widely used machine learning algorithms. Decision trees used to construct the random forest may have low classification accuracies or high correlations, which affects the comprehensive performance of the random forest. Aiming at these problems, the authors proposed an improved random forest based on the classification accuracy and correlation measurement of decision trees in this paper. Its main idea includes two parts, one is retaining the classification and regression trees (CARTs) with better classification effects, the other is reducing the correlations between the CARTs. Specifically, in the classification effect evaluation part, each CART was applied to make predictions on three reserved data sets, then the average classification accuracies were achieved, respectively. Thus, all the CARTs were sorted in descending order according to their achieved average classification accuracies. In the correlation measurement part, the improved dot product method was proposed to calculate the cosine similarity, i.e., the correlation, between CARTs in the feature space. By using the achieved average classification accuracy as reference, the grid search method was used to find the inner product threshold. On this basis, the CARTs with low average classification accuracy among CART pairs whose inner product values are higher than the inner product threshold were marked as deletable. The achieved average classification accuracies and correlations of CARTs were comprehensively considered, those with high correlation and weak classification effect were deleted, and those with better quality were retained to construct the random forest. Multiple experiments show that, the proposed improved random forest achieved higher average classification accuracy than the five random forests used for comparison, and the lead was stable. The G-means and out-of-bag data (OBD) score obtained by the proposed improved random forest were also higher than the five random forests, and the lead was more obvious. In addition, the test results of three non-parametric tests show that, there were significant diversities between the proposed improved random forest and the other five random forests. This effectively proves the superiority and practicability of the proposed improved random forest.

Firm heterogeneity, financial frictions and ambiguity

This paper studies the effects of ambiguity (Knightian uncertainty) on business cycles and inequality in an economy with heterogeneous agents. Ambiguity-averse entrepreneurs operate in a model with financial frictions and a market-wide source of ambiguous information. Entrepreneurs employ a worst-case criterion to formulate expectations about the total factor productivity and are heterogeneous in terms of assets and productivity. Comparing our economy with one that has the same fundamentals but lacks uncertainty, we observe that ambiguity: (i) raises the productivity threshold to access the market, (ii) does not alter the relative consumption gap between active and inactive entrepreneurs, and (iii) widens the consumption gap between entrepreneurs and workers. We also find that, in the long-run, an economy featuring ambiguity accumulates more assets and produces more. This is the consequence of entrepreneurs' hedging strategy and the wage suppression caused by ambiguity.

First Measurement of the Nuclear-Recoil Ionization Yield in Silicon at 100eV.

We measured the nuclear-recoil ionization yield in silicon with a cryogenic phonon-sensitive gram-scale detector. Neutrons from a monoenergetic beam scatter off of the silicon nuclei at angles corresponding to energy depositions from 4keV down to 100eV, the lowest energy probed so far. The results show no sign of an ionization production threshold above 100eV. These results call for further investigation of the ionization yield theory and a comprehensive determination of the detector response function at energies below the keV scale.

Geo-Based Assessment of Vegetation Health Related to Agroecological Practices in the Southeast of Togo

In the context of climate change, the need to contribute to achieving Sustainable Development Goal (SDG) 2 is no longer in doubt, especially in sub-Saharan Africa. In this study of the landscape within 10 km of the Donomadé model farm, southeastern Togo, researchers sought to assess vegetation health in ecosystems and agrosystems, including their capacity to produce biomass for agroecological practices. Sentinel-2 sensor data from 2015, 2017, 2020, and 2022 were preprocessed and used to calculate the normalized vegetation fire ratio index (NBR), the vegetation fire severity index (dNBR), and CASA-SEBAL models. From these different analyses, it was found that vegetation stress increased across the landscape depending on the year of the time series. The research estimated that 9952.215 ha, 10,397.43 ha, and 9854.90 ha were highly stressed in 2015, 2017, and 2020, respectively. Analysis of the level of interannual severity revealed the existence of highly photosynthetic areas that had experienced stress. These areas, which were likely to have been subjected to agricultural practices, were estimated to be 8704.871 ha (dNBR2017–2015), 8253.17 ha (dNBR2020–2017), and 7513.93 ha (dNBR2022–2020). In 2022, the total available biomass estimated by remote sensing was 3,741,715 ± 119.26 kgC/ha/y. The annual average was 3401.55 ± 119.26 kgC/ha/y. In contrast, the total area of healthy vegetation was estimated to be 4594.43 ha, 4301.30 ha, and 4320.85 ha, in 2015, 2017, and 2022, respectively. The acceptance threshold of the net primary productivity (NPP) of the study area was 96%. The coefficient of skewness (0.81 ± 0.073) indicated a mosaic landscape. Productive and functional ecosystem components were present, but these were highly dispersed. These findings suggest a great opportunity to promote agroecological practices. Mulching may be an excellent technique for enhancing overall ecosystem services as targeted by the SDGs, by means of reconversion of plant biomass consumed by vegetation fires or slash-and-burn agricultural practices.