Considering Existing Factors That May Cause Radiation Hormesis at <100 mSv and Obey the Linear No-Threshold Theory at ≥100 mSv

The linear no-threshold (LNT) theory describes the linear relationship between a radiation dose and its effects. However, whether the linear relationship is maintained at low radiation doses has yet to be determined. Many previous studies support the radiation hormesis theory, which states that radiation has beneficial effects on health. In this viewpoint, we propose a mathematical function fitted to a model consistent with both the LNT at ≥100 mSv and radiation hormesis theories at <100 mSv, and the model requires a factor whose amount or activity takes a mountain-like shape versus the radiation dose and have one maximum value at 40.9 mSv. We searched a wide range of factors with these features based on searches on PubMed, and then evaluated whether these factors were suitable candidates consistent with both the LNT and radiation hormesis theories. Our consideration indicated that these factors did not completely follow the equation suggested at this time. Of course, other theories do not deny that these factors are involved in hormesis. However, based on our theory, still unknown factors may be involved in radiation hormesis, and then such unknown factors which are activated at <100 mSv should be searched.

Improved Powder Equivalence Model for the Mix Design of Self-Compacting Concrete with Fly Ash and Limestone Powder

The use of fly ash (FA) limestone and powder (LP) in combination with cement in concrete has several practical, ecological, and economic advantages by reducing carbon dioxide emissions, reducing the excessive consumption of natural resources, and contributing to a cleaner production of self-compacting concrete (SCC). A mix design method for SCC based on paste rheological threshold theory can guide the SCC mix design by paste tests. This method can be visualized by the self-compacting paste zone (SCP zone), a plane area where all the mix points meet the paste threshold theory, and SCC zone, a plane area consisting of all the mix points satisfying the criteria of qualified SCC. In the case of cement SCC, the SCP zone coheres with the SCC zone. However, in the case of the addition of FA or LP with different granulometry and shape characteristics from cement, experimental results indicate that the SCP zone is separated from the SCC zone. This work quantitatively studied the influence of FA and LP on the movement of the SCP zone by introducing the improved powder equivalence model. The improved model was obtained by powder equivalence coefficients calculated through the mortar test results with or without FA or LP, instead of SCC tests in the former method. The equivalence coefficients by volume of FA and LP are 0.55 and 0.79, respectively, which means that 1.82 unit volume of FA or 1.27 unit volume of LP is equivalent to one unit volume of cement. The improved powder equivalence model was verified by the successful preparation of SCC incorporating FA or LP simply and effectively. The equivalent SCP zone cohered better with the SCC zone than the former SCP zone, which could guide the quick mix design of SCC without SCC premix tests.

The persistence of family firms: How does performance threshold affect family firm exit?

Research on family firms provides mixed evidence of the effect of family ownership on firm performance and exit outcomes. Drawing on threshold theory and the socioemotional wealth perspective, we argue that family firms have lower performance thresholds than non-family firms, reducing the likelihood of firm exit. Using a longitudinal dataset of 1191 firms over the period 2008–2011, we find support for this contention, suggesting that performance threshold is an important, yet poorly studied, construct for understanding exits of family versus non-family firms.Plain English Summary Why firms with similar economic performance make different exit decisions? We find evidence that family firms have lower “performance thresholds” than non-family firms, reducing family firms’ likelihood of exit. Using a longitudinal dataset, we examine differences in performance threshold between family and non-family firms and help clarify why some firms persist with their ventures even though their performance may indicate they should exit the market. Our theory and related findings suggest that nonfinancial attributes such as identity, the ability to exercise family influence, and to hand the business down to future generations may affect family firms’ attitudes toward exit decisions. Our study contributes to sharpening our understanding of exit in family firms while motivating future work on exit strategies in family firms and other contexts.

Validity and Utility of the Test of Creative Thinking Drawing Production for Dutch Adolescents

We examined the divergent validity and utility of the Test for Creative Thinking–Drawing Production (TCT-DP) in an identification protocol for high-ability students that included measures of intelligence, school motivation, inquisitiveness, creativity, and academic achievement. Data were collected from seventh-grade students across 6 years ( n = 710). Small significant correlations between the different measures indicated that the TCT-DP did measure a construct separate from intelligence, school motivation, inquisitiveness, and academic achievement. Furthermore, creativity did not significantly affect academic achievement when controlling for intelligence, school motivation, and inquisitiveness. We did not find support for threshold theory. Finally, we concluded that the TCT-DP provides useful additional information on creativity for high-ability identification in which measures of intelligence, school motivation, and inquisitiveness are already included. Thus, this study’s findings provide evidence for the utility and divergent validity of the TCT-DP when used with a Dutch population.

Coupling threshold theory and satellite-derived channel width to estimate the formative discharge of Himalayan foreland rivers

We propose an innovative methodology to estimate the formative discharge of alluvial rivers from remote sensing images. This procedure involves automatic extraction of the width of a channel from Landsat Thematic Mapper, Landsat 8, and Sentinel-1 satellite images. We translate the channel width extracted from satellite images to discharge using a width–discharge regime curve established previously by us for the Himalayan rivers. This regime curve is based on the threshold theory, a simple physical force balance that explains the first-order geometry of alluvial channels. Using this procedure, we estimate the formative discharge of six major rivers of the Himalayan foreland: the Brahmaputra, Chenab, Ganga, Indus, Kosi, and Teesta rivers. Except highly regulated rivers (Indus and Chenab), our estimates of the discharge from satellite images can be compared with the mean annual discharge obtained from historical records of gauging stations. We have shown that this procedure applies both to braided and single-thread rivers over a large territory. Furthermore, our methodology to estimate discharge from remote sensing images does not rely on continuous ground calibration.

The Half Life of Stress: Caregiver Stress Increases Next-Day Severity of Behavioral Symptoms of Dementia

The progressively lowered stress threshold theory posits that behavioral symptoms of dementia (BSD) are reactions to environmental and care related stressors. In line with this theory, this study tests whether the stress experienced the caregiver impacts BSD expression. Caregivers to persons with dementia recruited online completed daily diary surveys for 21 days reporting on daily contextual and environmental factors of caregiving life. Using multi-level modeling of diaries (n=911) nested within participants (N=51), two daily caregiver stressors (conflict with someone other than the person with dementia, stress about own personal health) were examined as predictors of BSD. The outcome of BSD was measured as severity (a rating on a Likert scale of 1-5 that was then person-centered to represent deviations from average severity). Covariates in the model included relationship type, caregiver age, as well as stressors to the care recipient known to increase BSD. On days when a caregiver had a conflict with others the severity of the care recipient’s BSD increased by 1.44 points from average (p&lt;.001, CI 1.05-1.75). In a time-lagged model, we observe that a caregiver having a conflict yesterday impacts today’s BSD severity by an increase of 0.43 points from average (p = 0.027, CI 0.05-0.81). Caregivers’ stress about their own health did not have a significant impact on the same day or next day BSD severity rating. These findings demonstrate that the well-being of the caregiver has measurable immediate impacts on the well-being of the person living with dementia, and suggests not all stress is equal.

Coupling threshold theory and satellite image derived channel width to estimate the formative discharge of Himalayan Foreland rivers

We propose an innovative methodology to estimate the formative discharge of alluvial rivers from remote sensing images. This procedure involves automatic extraction of the width of a channel from Landsat Thematic Mapper, Landsat 8, and Sentinel-1 satellite images. We translate the channel width extracted from satellite images to discharge by using a widthdischarge regime curve established previously by us for the Himalayan Rivers. This regime curve is based on the threshold theory, a simple physical force balance that explains the first-order geometry of alluvial channels. Using this procedure, we estimate the discharge of six major rivers of the Himalayan Foreland: the Brahmaputra, Chenab, Ganga, Indus, Kosi, and Teesta rivers. Except highly regulated rivers (Indus and Chenab), our estimates of the discharge from satellite images can be compared with the mean annual discharge obtained from historical records of gauging stations. We have shown that this procedure applies both to braided and single-thread rivers over a large territory. Further our methodology to estimate discharge from remote sensing images does not rely on continuous ground calibration.