Positive Coefficient Research Articles

The Nexus Between Revenue Generation and Economic Growth in Nigeria

The general objective of the study is to examine the relationship between revenue generation and economic growth in Nigeria. Ex-post facto research design was used with secondary data collected from CBN database (2012-2022). The dependent variable was economic growth and measured by gross domestic product GDP while the independent variables was revenue generation and measured by oil and non-oil revenue. The study adopt usage the autoregressive distributed lag ARDL model for the data analysis which shows the long-run relationship between revenue generation and economic growth in Nigeria. It was discovered that oil revenue (OILR) exerts an insignificant positive effect on economic growth in Nigeria in the long run at 5% significant value. It implies that a unit increase in oil revenue will lead to 3.709184 units increase in economic growth in Nigeria. Conversely, non-oil revenue has a positive and significant coefficient of 1.257631 units. This implies that a unit increase in non- oil revenue will bring about 1.257631 units increase in economic growth in Nigeria in the long. The study recommends that effort should be made by the governments to diversify the main revenue source from oil to other sectors of the economy such as agriculture, extractive industries in order to increase revenue generated from other sources

The value of lung ultrasound score in neonatal respiratory distress syndrome: a prospective diagnostic cohort study.

The accurate diagnosis of critically ill patients with respiratory failure can be achieved through lung ultrasound (LUS) score. Considering its characteristics, it is speculated that this technique might also be useful for patients with neonatal respiratory distress syndrome (NRDS). Thus, there is a need for precise imaging tools to monitor such patients. This double-blind randomized cohort study aims to investigate the impact of LUS and related scores on the severity of NRDS patients. This study was conducted as a prospective double-blind randomized study. Bivariate correlation analysis was conducted to investigate the relationship between LUS score and Oxygenation Index (OI), Respiratory Index (RI), and Sequential Organ Failure Assessment (SOFA) score. Spearman's correlation coefficient was used to generate correlation heat maps, elucidating the associations between LUS and respective parameters in different cohorts. Receiver Operating Characteristic (ROC) curves were employed to calculate the predictive values, sensitivity, and specificity of different scores in determining the severity of NRDS. This study ultimately included 134 patients admitted to the intensive care unit (ICU) between December 2020 and June 2022. Among these patients, 72 were included in the NRDS cohort, while 62 were included in the Non-NRDS (N-NRDS) cohort. There were significant differences in the mean LUS scores between NRDS and N-NRDS patients (p < 0.01). The LUS score was significantly negatively correlated with the OI (p < 0.01), while it was significantly positively correlated with the RI and SOFA scores (p < 0.01). The correlation heatmap revealed the highest positive correlation coefficient between LUS and RI (0.82), while the highest negative correlation coefficient was observed between LUS and OI (-0.8). ROC curves for different scores demonstrated that LUS score had the highest area under the curve (0.91, 95% CI: 0.84-0.98) in predicting the severity of patients' conditions. The combination of LUS and other scores can more accurately predict the severity of NRDS patients, with the highest AUC value of 0.93, significantly higher than using a single indicator alone (p < 0.01). Our double-blind randomized cohort study demonstrates that LUS, RI, OI, and SOFA scores can effectively monitor the lung ventilation and function in NRDS. Moreover, these parameters and their combination have significant predictive value in evaluating the severity and prognosis of NRDS patients. Therefore, these results provide crucial insights for future research endeavors.

Analysis of Genetic Diversity in Romanian Carpatina Goats Using SNP Genotyping Data.

Animal husbandry is one of man's oldest occupations. It began with the domestication of animals and developed continuously, in parallel with the evolution of human society. The selection and improvement of goats in Romania was not a clearly defined objective until around 1980. In recent years, with the increasing economic value given to goats, breeding programs are becoming established. In Romania, a few goat genetic studies using microsatellites and mtDNA have been carried out; however, a systematic characterization of the country's goat genomic resources remains missing. In this study, we analyzed the genetic variability of Carpatina goats from four distinct geographical areas (northern, north-eastern, eastern and southern Romania), using the Illumina OvineSNP60 (RefSeq ARS1) high-density chip for 67 goats. Heterozygosity values, inbreeding coefficients and effective population size across all autosomes were calculated for those populations that inhabit high- and low-altitude and high- and low-temperature environments. Diversity, as measured by expected heterozygosity (HE), ranged from 0.413 in the group from a low-temperature environment to 0.420 in the group from a high-temperature environment. Within studied groups, the HT (high temperature) goats were the only group with a positive but low average inbreeding coefficient value, which was 0.009. After quality control (QC) analysis, 46,965 SNPs remained for analysis (MAF < 0.01). LD was calculated for each chromosome separately. The Ne has been declining since the time of domestication, having recently reached 123, 125, 185 and 92 for the HA (high altitude), LA (low altitude), HT (high temperature) and LT (low temperature) group, respectively. Our study revealed a low impact of inbreeding in the Carpatina population, and the Ne trend also indicated a steep decline in the last hundred years. These results will contribute to the genetic improvement of the Carpatina breed.

Extended-Range Forecast of Winter Rainfall in the Yangtze River Delta Based on Intra-Seasonal Oscillation of Atmospheric Circulations

The Yangtze River Delta (YRD) is an important economic region in China. Heavy winter rainfall may pose serious threats to city operations. To ensure the safe operation of the city, meteorological departments need to provide forecast results for the Spring Festival travel rush weather service. Therefore, the extended-range forecast of winter rainfall is of considerable importance. To solve this problem, based on the analysis of low-frequency rainfall and the intra-seasonal oscillation of atmospheric circulation, an extended-range forecast model for winter rainfall is developed using spatiotemporal projection methods and is applied to a case study from 2020. The results show that: (1) The precipitation in the YRD during the winter has a significant intra-seasonal oscillation (ISO) with a periodicity of 10–30 d. (2) The atmospheric circulations associated with winter rainfall in the YRD have a significant characteristic of low-frequency oscillation. From a 30-day to a 0-day lead, large modifications appear in the low-frequency atmospheric circulations at low, mid, and high latitudes. At low latitudes, strong wet convective activity characterized by a negative OLR combined with a positive RH700 correlation coefficient moves northwestward and covers the entire YRD. Meanwhile, the Western Pacific subtropical high (WPSH) characterized by a positive Z500 anomaly enhances and lifts northward. At mid and high latitudes, the signal of negatively correlated Z500 northwest of Lake Balkhash propagates southeastward, indicating the cold is air moving southward. Multiple circulation factors combine together and lead to the precipitation process in the YRD. (3) Taking the intra-seasonal dynamical evolution process of the atmospheric circulation as the prediction factor, the spatiotemporal method is used to build the model for winter mean extended-range precipitation anomaly tendency in the YRD. The hindcast for the recent 10 years shows that the ensemble model has a higher skill that can reach up to 20 days. In particular, the skill of the eastern part of the YRD can reach 25 days. (4) The rainfall in the 2019/2020 winter has a significant ISO. The ensemble model could forecast the most extreme precipitation for 20 days ahead.

Pengaruh Profitabilitas, Likuiditas, Dan Leverage Terhadap Keputusan Hedging

International trade is mostly carried out by companies in Indonesia. International trade obviously related with foreign currency exchange rates. This exchange rate is fluctuating that can cause company has a financial risk such as declining company profit, increasing corporate debt, and weakening financial performance. To conques this problem, hedging decisions are one way to maintain exchange rates and minimize financial risks that may occur. Therefore, this study aims to determine the effect of profitability, liquidity, and leverage on hedging decision. This study used secondary data with a quantitative approach, where the sample selected in this study used purposive sampling techniques. The population of non primary consumer goods sector company listed on the IDX is 136 companies to 16 companies selected by criteria, so there are 64 samples. The data analysis method that used in this study is logistic regression analysis. Research data is processed using SPSS software. The result of this study showed that profitability had a positive regression coefficient with a significance value of 0,001 &lt; 0,05, indicating that profitability had a positive and significant effect on hedging decision. Liquidity had a significance value of 0,003 &lt; 0,05, indicating that liquidity had a negative effect and significant effect on hedging decision. Leverage had a significance value of 0,642 &gt; 0,05, indicating that leverage had no effect on hedging decision. Profitability, liquidity, and leverage simultancously had a significance value of 0,000 &lt; 0,05, indicating that profitability, liquidity, and leverage simultancously had a significant effect on hedging decision in non primary consumer goods sector company listed on the Indonesia Stock Exchange for the period 2018-2021. Keywords: Profitability, Liquidity, Leverage, Hedging Decision

The Intricate Impression of Tourism, Patent, And Renewable Energy on Environmental Sustainability

The growing global attention to indicating climate conversion and plummeting carbon dioxide (CO2) emanations has spurred researchers to examine the influence of several factors on promoting environmental sustainability. This research examines the intricate role of tourism, patent applications, rent from natural resources, and utilization of renewable power in carbon dioxide secretions in Bangladesh. For this purpose, data has been collected from 1995 to 2019 from World Development Indicators (WDI). Augmented Dickey-Fuller (ADF) and the Phillips-Perron (PP) and the ARDL bound cointegration procedures are employed to determine the existence of stationary data and cointegration among variables respectively. The Autoregressive Distributive Lag (ARDL) procedure is used to consider the effects of the chosen variables on CO2 emissions over the short and long run. VIF test, White's test, and the Breusch-Godfrey test are employed to check multicolinearity, homoscedasticity, and autocorrelation respectively. The research discloses that it is vital to expand the usage of renewable energy sources while simultaneously decreasing natural resource rent by limiting natural resource extraction for a sustainable environment. Although the statistical insignificance of the long-term coefficient of tourism has been observed, the study reveals a negative coefficient for tourism, suggesting the possible efficacy of sustainable tourism practices for mitigating CO2 emissions. The findings also demonstrate the long-term contribution of innovation activities to environmental degradation through the positive coefficient of patent applications. The research results offer significant insights for policymakers and stakeholders involved in the pursuit of a sustainable and ecologically conscious future in Bangladesh.

Construction of an evaluation index system for the capability of comprehensive control of mountain - type zoonotic visceral leishmaniasis based on the One Health concept

To construct an evaluation index system for the capability of comprehensive control of mountain-type zoonotic visceral leishmaniasis based on the One Health concept, so as to provide insights into the control and elimination of mountain-type zoonotic visceral leishmaniasis using the One Health approach. A preliminary evaluation index system was constructed based on literature review, panel discussions and field surveys. Thirty-three experts were selected from 7 provincial disease control and prevention centers in Beijing Municipality, Hebei Province, Shanxi Province, Henan Province, Sichuan Province, Shaanxi Province and Gansu Province where mountain-type zoonotic visceral leishmaniasis was endemic, and two rounds of expert consultations were conducted to screen the indicators. The positive coefficient, degree of concentration, degree of coordination, and authority of the experts were calculated, and the normalized weights of each index were calculated with the analytic hierarchy process. The response rates of questionnaires during two rounds of expert consultation were both 100.00% (33/33), and the authority coefficients of the experts were 0.86 and 0.88, respectively. The coefficients of coordination among experts on the rationality, importance, and operability of the indicators were 0.392, 0.437, 0.258, and 0.364, 0.335, 0.263, respectively (all P values < 0.05). Following screening, the final evaluation index system included 3 primary indicators, 17 secondary indicators, and 50 tertiary indicators. The normalized weights of primary indicators "external environment", "internal support" and "comprehensive control" were 16.98%, 38.73% and 44.29%, respectively. Among the secondary indicators of the primary indicator "external environment", the highest weight was seen for natural environment (66.67%), and among the secondary indicators of the primary indicator "internal support", the lowest weight was seen for the scientific research for visceral leishmaniasis control (8.26%), while other indicators had weights of 12.42% to 13.38%. Among the secondary indicators of the primary indicator "comprehensive control", the weight was 16.67% for each indicator. An evaluation index system has been constructed for the capability of comprehensive control of mountain-type zoonotic visceral leishmaniasis based on the One Health concept. In addition to assessment of the effect of conventional mountain-type zoonotic visceral leishmaniasis control measures, this index system integrates the importance of top-level design, organizational management, and implementation of control measures, and includes indicators related to multi-sectoral cooperation.

How close are the classical two-body potentials to abinitio calculations? Insights from linear machine learning based force matching.

In this work, we propose a linear machine learning force matching approach that can directly extract pair atomic interactions from abinitio calculations in amorphous structures. The local feature representation is specifically chosen to make the linear weights a force field as a force/potential function of the atom pair distance. Consequently, this set of functions is the closest representation of the abinitio forces, given the two-body approximation and finite scanning in the configurational space. We validate this approach in amorphous silica. Potentials in the new force field (consisting of tabulated Si-Si, Si-O, and O-O potentials) are significantly different than existing potentials that are commonly used for silica, even though all of them produce the tetrahedral network structure and roughly similar glass properties. This suggests that the commonly used classical force fields do not offer fundamentally accurate representations of the atomic interaction in silica. The new force field furthermore produces a lower glass transition temperature (Tg ∼ 1800K) and a positive liquid thermal expansion coefficient, suggesting the extraordinarily high Tg and negative liquid thermal expansion of simulated silica could be artifacts of previously developed classical potentials. Overall, the proposed approach provides a fundamental yet intuitive way to evaluate two-body potentials against abinitio calculations, thereby offering an efficient way to guide the development of classical force fields.

Genome-wide association study reveals the genetic basis of amino acids contents variations in Peanut (Arachis hypogaea L.).

Peanut is a significant source of protein for human consumption. One of the primary objectives in peanut breeding is the development of new cultivars with enhanced nutritional values. To further this goal, a genome-wide association study (GWAS) was conducted to analyze seed amino acids contents in 390 diverse peanut accessions collected worldwide, mainly from China, India, and the United States, in 2017 and 2018. These accessions were assessed for their content of 10 different amino acids. Variations in amino acids contents were observed, and arginine (Arg) was found to have the highest average value among all the amino acids quantified. The geographical distribution of the accessions also revealed variations in amino acids contents. High and positive correlation coefficients were observed among the amino acids, suggesting linked metabolic pathways or genetic regulation. A total of 88 single nucleotide polymorphisms (SNPs) spanning various chromosomes were identified, each associated with different amino acids. By using a combination of GWAS, expression anlaysis, and genomic polymorphisim comparisions, theAhy_A09g041582 (LAC15) gene located on chromrosome A09 was identified as the key candidate which might be involved in plant growth and regulation and may alter amino acids levels. Expression analysis indicated that Ahy_A09g041582 has higher expressions in the shells and seeds than other genes located in the candidate region. This study may help with marker-based breeding of peanuts with higher nutritional value and offers fresh insights into the genetic basis of the amino acids contents of peanuts.

Simultaneous Occurrence of Traveling Ionospheric Disturbances, Farley Buneman and Gradient Drift Instabilities Observed by the Zhongshan SuperDARN HF Radar

AbstractWe show that Traveling Ionospheric Disturbances (TIDs) may affect the Farley Buneman Instability (FBI) and Gradient Drift Instability (GDI) echoes referred to as the Near Range Echoes (NREs) in the SuperDARN radar backscatter from the lower part of the E‐region. TIDs and NREs are observed concomitantly by the Zhongshan SuperDARN radar (69.38°S, 76.38°E) in the far and near ranges, respectively. At the moment, there is no study about the effects of TIDs on the NREs caused by the FBI using the SuperDARN radars. The GDI are more likely to occur at a lower altitude while FBI occurs at a slightly higher altitude in the lower part of the ionospheric E‐region. We use the Spearman Correlation Coefficient (SCC) to show that a part of the NREs backscatter power could be statistically explained by the MSTIDs backscatter power received by the same radar. We also investigate the simultaneous occurrence rate of the NREs and MSTIDs during the 24th solar cycle. Seasonal variability shows that MSTIDs‐NREs events over Zhongshan mostly occur in summer and equinoxes during local night and morning. The majority of these events lasted between ∼4 and ∼8 hr. Most events disappeared early in the morning. Statistics of the Spearman correlation coefficient values show that ∼9% of NRE amplitude modulation could be due to the MSTIDs. There are almost equal numbers of negative and positive Spearman correlation coefficient values. The relative velocity between the E‐region NREs and the F‐region MSTIDs switching the electric field polarities between the crests and troughs could be the cause of those equal number of the Spearman correlation coefficient values. The orientation of the ionospheric current relative to the MSTID polarization electric field may also play a significant role in the reported Spearman correlation coefficient values. We argue that in some cases, the TIDs might have been close enough to the NREs altitude to modulate them directly by transporting the plasma up and down through shear or compression.

Exploring the complex dynamics of a diffusive epidemic model: Stability and bifurcation analysis.

The recent pandemic has highlighted the need to understand how we resist infections and their causes, which may differ from the ways we often think about treating epidemic diseases. The current study presents an improved version of the susceptible-infected-recovered (SIR) epidemic model, to better comprehend the community's overall dynamics of diseases, involving numerous infectious agents. The model deals with a non-monotone incidence rate that exhibits psychological or inhibitory influence and a saturation treatment rate. It has been identified that depending on the measure of medical resources and the effectiveness of their supply, the model exposes both forward and backward bifurcations where two endemic equilibria coexist with infection-free equilibrium. The model also experiences local and global bifurcations of codimension two, including saddle-node, Hopf, and Bogdanov-Takens bifurcations. Additionally, the stability of equilibrium points is investigated. For a spatially extended SIR model system, we have shown that cross-diffusion allows S and I populations to coexist in a habitat. Also, the Turing instability requirements and Turing bifurcation regime are derived. The relationship between distinct role-playing model parameters and various pattern formations like spot and stripe patterns is validated by carrying out in-depth numerical simulations. The findings in the vicinity of the endemic equilibrium solution demonstrate the significance of positive and negative valued cross-diffusion coefficients in regulating the genesis of spatial patterns in susceptible as well as diseased individuals. The discussion of the findings of epidemiological ramifications concludes the manuscript.

Redefining Employability Skills in the Fourth Industrial Revolution: A Comparative Analysis with Nyerere's Second and Third Industrial Revolutions

The late Mwalimu Julius Nyerere is considered as one of the pioneers of the African revolution, his struggles entailed the economic change that embodied the employability transformations in order to increase production and enhance growth. However, changes in the industrial revolution as the result of technological changes resulted in the shift of employment patterns across generations from the Nyerere generation which represent the second and third industrial generation to the new fourth industrial revolution (4IR) which is characterized by high technological innovations. These innovations have led to the change in the government policies in order to equip youths especially university graduates with relevant skills to cope with the speed of 4IR. Despite the efforts undertaken by governments to address and enhance soft and technical skills development most graduates have been fearing of losing chances before these technological innovations, therefore the current study explores youth perception on the employability status in the face of 4IR in Tanzania using probit model from 100 students at Mzumbe university who were randomly sampled. The results reveal that there is a positive relationship between life/soft skills, technological/hard skills, awareness of 4IR, preparation for self-employment, and graduate’s employability in 4IR, shown by positive coefficients of 0.514, 0.337, 0.976 and 1.038 respectively. Life/soft skills, technological/hard skills, awareness of industry 4.0, and preparation for self-employment were found significant at a 5% significance level with p-values of 0.000, 0.034, 0.033, and 0.029 respectively. Simply the findings suggest that a graduate (finalist) who is aware of industry 4.0, is prepared for self-employment, and have soft/life skills and technological/hard skills. Therefore, the study recommends that higher learning institutions and government authorities governing higher learning should be investment in the soft skills among youths, and enhance entrepreneurial course that constitutes innovation and creativity components in order to enable graduates and youths be able to cope with the speed of the technological and industrial demands for employability.

). The competitiveness disparity between core and peripheral EU countries: an empirical analysis with panel ARDL approach

Purpose- This study empirically investigates whether there is an asymmetry between the competitiveness of the core and peripheral EU countries in the post-monetary union period, which includes the public debt crisis. Methodology- This paper analyzes the long and short-term effects of the interest rate for public bond yields and real effective exchange rate on public debt in core (Germany, Austria, Belgium, Denmark, and the Netherlands) and peripheral (Greece, Ireland, Italy, Portugal, and Spain) EU countries using the panel linear Autoregressive Distributive Lag model. In the study, second-generation unit root tests, Westerlund's (2007) cointegration test, and short and long-term MG, PMG, and DFE panel econometric methods are employed. Findings- According to the primary findings of the study: (i) while the interest rate for public bond yields is not effective on public debt in core EU countries, it has an increasing effect on public debt with a high positive coefficient in peripheral EU countries. (ii) The long-term coefficient of the real effective exchange rate in the peripheral EU countries is higher than in the core EU countries. According to this conclusion, the increase in the real effective exchange rate augments the public debt of the peripheral EU countries at a higher level than the core EU countries. Conclusion- Contrary to the monetarist approach that relies on the role of one last funder, these findings contribute to the literature by supporting the first two conditions of the Optimum Currency Area, the Varieties of Capitalism, Comparative Political Economy, and Fundamentalist approaches, which reveal the asymmetrical structure between the competitiveness of the core and peripheral EU countries. Keywords: EMU public debt crisis, core EU countries, peripheral EU countries, panel ARDL model, competitiveness differences JEL Codes: C45, F45, N14, N24

A reduction of the separability problem to SPC states in the filter normal form

It was recently suggested that a solution to the separability problem for states that remain positive under partial transpose composed with realignment (the so-called symmetric with positive coefficients states or simply SPC states) could shed light on entanglement in general. Here we show that such a solution would solve the problem completely.Given a state in $ \mathcal{M}_k\otimes\mathcal{M}_m$, we build a SPC state in $ \mathcal{M}_{k+m}\otimes\mathcal{M}_{k+m}$ with the same Schmidt number. It is known that this type of state can be put in the filter normal form retaining its type. A solution to the separability problem in $\mathcal{M}_k\otimes\mathcal{M}_m$ could be obtained by solving the same problem for SPC states in the filter normal form within $\mathcal{M}_{k+m}\otimes\mathcal{M}_{k+m}$. This SPC state can be built arbitrarily close to the orthogonal projection on the symmetric subspace of $ C^{k+m}\otimes C^{k+m}$. All the information required to understand entanglement in $ \mathcal{M}_s\otimes\mathcal{M}_t$ $(s+t\leq k+m)$ lies inside an arbitrarily small ball around that projection. We also show that the Schmidt number of any state $\gamma\in\mathcal{M}_n\otimes\mathcal{M}_n$ which commutes with the flip operator and lies inside a small ball around that projection cannot exceed $\lfloor\frac{n}{2}\rfloor$.

SOLVING BIPOLAR FULLY FUZZY SYLVESTER MATRIX EQUATIONS WITH NEGATIVE FUZZY NUMBERS

Sylvester matrix equations play a crucial role in control theory for controller design. Bipolar Fully Fuzzy Sylvester Matrix Equations (FFSME), incorporating both positive and negative components, are employed in controller design to address uncertainties that may affect a system’s performance and stability. However, there is not much existing research on combining bipolar fuzzy numbers and FFSME,and most of them mainly deal with positive coefficients. Thus, this paper presents a method that enables solving the negative coefficient of bipolar FFSME in the form of Left-Right (LR) triangular fuzzynumbers using an Associated Bipolar Linear System (ABLS). To obtain the ABLS, bipolar FFSME is transformed into a bipolar Fully Fuzzy Linear System (FFLS) using the Kronecker product and Vecoperator. Subsequently, the solution is derived through the inverse method, and the equation of the ABLS is rearranged as a bipolar fuzzy matrix. Additionally, this paper provides two numerical examples to illustrate the applicability of the constructed method.

THE PROFIT EFFICIENCY OF MORINGA OLEIFERA PRODUCTION IN OSUN STATE, NIGERIA

This study examined the profit efficiency of Moringa oleifera production by farmers in Osun State, Nigeria. Primary data were obtained from 150 respondents. Multistage sampling procedure was used for selecting respondents. The data were analyzed with the aid of descriptive statistics, budgetary analysis and stochastic frontier production function. The findings revealed that male predominate moringa enterprise with about 55.3% male, most producers fall between the age bracket 41-50years with a mean age of 44.92 (± 13.168) years and the average farm size is 0.3 hectares whilst indicating that most producers had less than 0.1 hectares of land. Moringa production had a benefit cost ratio of ₦5.852, profit margin of ₦0.182, expense structure ratio of ₦0.107, net return on investment ₦4.857, rate of return of ₦5.482 and profitability ratio of ₦0.981. The average profit efficiency of moringa producers was 18.73% on the profit frontier. Family labour, hired labour and transport cost were significant and had positive coefficient while the seed cost, pesticide cost, level of education and farm size are also significant but bears negative coefficient. The level of education and farm size are amongst the inefficiency variables considered. This study concludes that Moringa oleifera production is highly profitable but producers have not been able to maximize profit efficiency. It therefore recommends that producers improve on adding value to moringa products and extend their channels of distribution considering the cost incurred on transportation.

Fine-scale genetic structure in the orchid Gymnadenia conopsea is not associated with local density of flowering plants.

Density-dependent pollinator visitation can lead to density-dependent mating patterns and within-population genetic structure. In Gymnadenia conopsea, individuals in low-density patches receive more self pollen than individuals in high-density patches, suggesting higher relatedness at low density. Ongoing fragmentation is also expected to cause more local matings, potentially leading to biparental inbreeding depression. To evaluate whether relatedness decreases with local density, we analyzed 1315 SNP loci in 113 individuals within two large populations. We quantified within-population genetic structure in one of the populations, recorded potential habitat barriers, and visualized gene flow using estimated effective migration surfaces (EEMS). We further estimated the magnitude of biparental inbreeding depression that would result from matings restricted to within 5 m. There was no significant relationship between local density and relatedness in any population. We detected significant fine-scale genetic structure consistent with isolation by distance, with positive kinship coefficients at distances below 10 m. Kinship coefficients were low, and predicted biparental inbreeding depression resulting from matings within the closest 5 m was a modest 1-3%. The EEMS suggested that rocks and bushes may act as barriers to gene flow within a population. The results suggest that increased self-pollen deposition in sparse patches does not necessarily cause higher selfing rates or that inbreeding depression results in low establishment success of inbred individuals. The modest relatedness suggests that biparental inbreeding depression is unlikely to be an immediate problem following fragmentation of large populations. The results further indicate that habitat structure may contribute to governing fine-scale genetic structure in G. conopsea.

Electrically induced cancellation and inversion of piezoelectricity in ferroelectric Hf0.5Zr0.5O2

HfO2-based thin films hold huge promise for integrated devices as they show full compatibility with semiconductor technologies and robust ferroelectric properties at nanometer scale. While their polarization switching behavior has been widely investigated, their electromechanical response received much less attention so far. Here, we demonstrate that piezoelectricity in Hf0.5Zr0.5O2 ferroelectric capacitors is not an invariable property but, in fact, can be intrinsically changed by electrical field cycling. Hf0.5Zr0.5O2 capacitors subjected to ac cycling undergo a continuous transition from a positive effective piezoelectric coefficient d33 in the pristine state to a fully inverted negative d33 state, while, in parallel, the polarization monotonically increases. Not only can the sign of d33 be uniformly inverted in the whole capacitor volume, but also, with proper ac training, the net effective piezoresponse can be nullified while the polarization is kept fully switchable. Moreover, the local piezoresponse force microscopy signal also gradually goes through the zero value upon ac cycling. Density functional theory calculations suggest that the observed behavior is a result of a structural transformation from a weakly-developed polar orthorhombic phase towards a well-developed polar orthorhombic phase. The calculations also suggest the possible occurrence of a non-piezoelectric ferroelectric Hf0.5Zr0.5O2. Our experimental findings create an unprecedented potential for tuning the electromechanical functionality of ferroelectric HfO2-based devices.

Evaluating Hydrogen-based Moderators in High-Temperature Gas-cooled Reactors with 5 wt% Enriched Uranium Annular Fuel Rods

Abstract Small Modular Reactors (SMRs) based on high temperature gas-cooled reactor (HTGR) technology are being developed for providing high-temperature process heat and high-efficiency (&amp;amp;gt;40%) electrical power generation. However, most of the HTGR-SMR concepts require high assay low enriched uranium (HALEU) fuel, with enrichments typically above 10 wt% 235U/U, to get sufficiently high burnup levels and fuel lifetime. The need for HALEU is primarily a consequence of the low volumetric density of fissionable material in tri-structural isotropic (TRISO) fuel particles, and also the use of graphite as a moderator/reflector. A previous study has shown that a modified prismatic HTGR fuel assembly with hydrogen-based moderator (7LiH) and cylindrical fuel elements of 5 wt% 235U/U enriched uranium can greatly reduce fuel consumption of a HTGR. However, such a design concept could lead to positive temperature reactivity coefficients (TRCs), making reactor control more challenging, with reduced passive safety. The purpose of this study is to evaluate variations of the hydrogen-based moderator in this alternative fuel assembly concept to identify configurations that achieve negative TRCs, thus improving passive safety characteristics. Calculation results demonstrate that negative TRCs can be achieved with reduced hydrogen mass such that natural uranium consumption is substantially less than that of the TRISO fuel concept, with comparable or higher core life. This study also explores the option of using 7LiOH and NaOH as hydrogen-based moderators, instead of 7LiH, thus allowing operation at higher temperatures, where hydrogen TRCs are lower.

On Global Solutions of Hyperbolic Equations with Positive Coefficients at Nonlocal Potentials

We study hyperbolic equations with positive coefficients at potentials undergoing translations with respect to the spatial independent variable. The qualitative novelty of the investigation is that the real part of the symbol of the differential-difference operator contained in the equation is allowed to change its sign. Earlier, only the case where the said sign is constant was investigated. We find a condition relating the coefficient at the nonlocal term of the investigated equation and the length of the translation, guaranteeing the global solvability of the investigated equation. Under this condition, we explicitly construct a three-parametric family of smooth global solutions of the investigated equation.