Natural Rate Research Articles

Smartphone Evaluation of Dynamic and Static Naturalness After Double-Eyelid Blepharoplasty.

Recent studies on post-operative measurements for upper blepharoplasty utilized static photographs, which fail to accurately reflect the post-surgical dynamic naturalness of the eyelids. This study aimed to analyze dynamic naturalness after double-eyelid blepharoplasty using a simple smartphone method involving slow-motion videos. This prospective observational study enrolled patients who underwent double-eyelid blepharoplasty using the flexible suspension technique (FST) and rigid fixation technique (RFT) and individuals with congenital double-eyelids. Demographic information was collected, and super-slow-motion videos of the eye-opening processes were recorded using a smartphone. Four keyframes were selected from each video, from which several parameters were measured. A third party evaluated the degree of naturalness of the photographs and eye-opening videos. Sixty women (20 per group) were enrolled. The fold-emerging delay (FED) score showed a linear correlation with the mean third-party dynamic naturalness rating (DNR) (R2=0.71, p<0.0001). The Puffy score showed a linear correlation with the mean third-party static naturalness rating (SNR) (R2=0.53, p<0.0001). For the congenital, FST, and RFT groups, respectively, the FED scores were 62.9±18.9, 52.2±17.7, and 26.3±18.3 (all p<0.05), the Puffy scores were 49.8±11.9, 55.9±11.0, and 62.6±12.4 (Congenital vs FST, p=0.055; others p<0.05), the mean third-party DNRs were 3.21±0.67, 2.47±0.62, and 1.78±0.74 (all p<0.0001), and the mean third-party SNRs were 3.01±0.78, 2.61±0.55, and 2.14±0.69 (all p<0.05). The two new indices obtained from the analysis of smartphone-captured super-slow-motion videos are good indicators of dynamic naturalness of double-eyelids created using upper blepharoplasty.

Study on pyrolysis process and mechanism of organic coating of waste polyesterimide enameled wire based on density functional theory

The pyrolysis treatment of waste polyesterimide enameled wire offers significant advantages such as continuous processing, non-hazardous nature, and high resource recovery rate. However, research on its pyrolysis process and mechanism remains insufficiently explored. In this study, techniques including thermogravimetry (TG), Fourier transform infrared spectroscopy(FT-IR), pyrolysis–gas chromatography-mass spectrometry(Py-GC/MS) were employed to investigate pyrolysis temperature, weight loss rate, pyrolysis and kinetic parameters, composition and distribution of pyrolysis products, and changes in functional groups under different temperatures and heating rates. The pyrolysis of polyesterimide enameled wire can be divided into three stages: volatilization of specific components (314.8 °C,1.6 %), rapid decomposition of polyesterimide (435.2 °C, 44.7 %), and generation of small organic molecules with the fixation of pyrolytic carbon (750 °C, 9.0 %). The main components of the pyrolysis gas products include aromatic compounds, ethers, aromatics, ketones, and carbon dioxide. At 400 °C, a substantial amount of pyrolysis gas products and free radicals are produced, with an increase in aromatic hydrocarbons. The carbon distribution in the pyrolysis products mainly focuses on C6-C10 and C11-C15, and many organic compounds such as benzoic acid, phenol, and aniline are generated. Based on density functional theory, the bond dissociation energies in the polyesterimide were calculated. This clarified the possible thermal decomposition pathways of the polyesterimide and provided the energy barrier values, elucidating the generation mechanism of pyrolysis products during thermal decomposition. The copper atom in specific location reduces the negative ESP of O and increases the positive ESP of H in EPI, which makes H more likely to attach to O. The presence of Cu increases the ESP range and promote the pyrolysis process. This study provides a theoretical basis for the high-value recycling of waste polyesterimide enamelled wire.

HIV disease progression among heterosexually-infected individuals before the introduction of universal ART in China: A linear mixed-effects model.

In 2016, China introduced universal antiretroviral therapy (ART) for all HIV-infected individuals regardless of CD4 cell count. However, the natural history and rate of CD4 count decline among heterosexually-infected individuals remain uncharacterized. Analyzing national surveillance data can address this gap and shed light on the pathogenesis of HIV in this population. We used a linear mixed-effects model to assess CD4 trajectory over time before ART initiation and estimated the median time from HIV seroconversion to reaching CD4 thresholds of < 500, < 350, and < 200 cell/mm3. From the Chinese HIV/AIDS Comprehensive Response Information Management System, 59,085 eligible individuals were identified, with 113 having data to estimate the date of HIV seroconversion. The linear mixed-effects models estimated an intercept of 23.64 (95% confidence interval [CI]: 22.41 to 24.87) and a slope of -1.32 (95% CI: -1.34 to -1.30) for males, and an intercept of 22.70 (95% CI: 21.00 to 24.40) and a slope of -1.29 (95% CI: -1.31 to -1.27) for females. The estimated median times from HIV seroconversion to reaching CD4 count thresholds of < 500, < 350, < 200 cells/mm3 were 0.97, 3.74, and 7.20 years for males, and 0.26, 3.09, and 6.48 years for females, respectively. Males consistently took longer to reach these CD4 count thresholds compared to females of the same age group. Older individuals (≥ 40 years) reached CD4 thresholds faster than younger individuals (15-29 years), indicating more rapid disease progression in older people living with HIV.

A practical framework for applied forestry assisted migration

Recent and projected changes in climate over this century pose an unprecedented threat to the health, diversity, and productivity of forest ecosystems. Forests have migrated and adapted to long-term changes in climate over thousands to millions of years; however, natural migration rates and adaptive responses of tree populations cannot match the rapid pace of current climate change. Consequently, more climate-informed approaches to reforestation are needed as current reforestation strategies using local seed sources may no longer be adequate to meet forest management objectives. Assisted migration is a climate change adaptation technique that can help maintain the ecosystem services and economic value that forests provide. Forestry assisted migration (FAM) focusses on the movement of populations of widespread, commercially, or ecologically important forest tree species within or just beyond their current ranges as a way to maintain forest productivity and health in the face of climate change. Although the forestry community recognizes FAM as a reforestation tool, guidance for planning and implementation of FAM is lacking and a framework that provides this guidance can prove useful to land managers with limited time and resources available who want to undertake FAM. We developed a practical framework (the FAM Framework) to provide a structured approach to ensure the most important considerations and best available science are utilized by land managers wanting to implement FAM on their land base. The FAM Framework incorporates multiple factors for the application of FAM in four sequential phases: assessment and analysis, climate-based plant material selection, seed procurement and deployment, and documentation and monitoring. The FAM Framework was tested by developing an assisted migration plan for the Superior National Forest, Minnesota (MN), and lessons learned from the development of this specific plan were used to revise and improve the FAM Framework for suitability across all lands. While originally designed to meet the needs of National Forest System land managers, it is relevant and applicable across the spectrum of land ownership because it incorporates consideration of critical elements in planning and implementing FAM on any landscape while facilitating adaptive management for active learning and future implementation.

A case study of consecutive pregnancies in a woman with liver cirrhosis and portal hypertension

Pregnancy in women with liver cirrhosis is a high-risk one that requires multidisciplinary care. Variceal bleeding occurs in up to half of women having associated portal hypertension and confers the greatest risk. Despite advances made in the management of such cases, maternal morbidity remains high. Pregnancy is rare in women with liver cirrhosis due to reduced natural fertility rates. We report a case of two consecutive pregnancies in a woman with liver cirrhosis. A 29-year-old primipara with hepatitis B-related liver cirrhosis with portal hypertension who had been on tenofovir for the past seven years. The first pregnancy was spontaneously conceived but the second was by assisted conception. Both pregnancies were complicated by recurrent episodes of variceal bleeding that necessitated multiple endoscopic variceal band ligation (EVBL) during pregnancy. Medical advancement has enabled women with cirrhosis to have more pregnancies with reduced maternal and perinatal morbidities. Multidisciplinary management is vital to achieving favourable pregnancy outcomes.

Enhancing Cellular and Enzymatic Properties Through In Vivo Continuous Evolution.

Directed evolution seeks to evolve target genes at a rate far exceeding the natural mutation rate, thereby endowing cellular and enzymatic properties with desired traits. In vivo continuous directed evolution achieves these purposes by generating libraries within living cells, enabling a continuous cycle of mutant generation and selection, enhancing the exploration of gene variants. Continuous evolution has become powerful tools for unraveling evolution mechanism and improving cellular and enzymatic properties. This review categorizes current continuous evolution into three distinct classes: non-targeted chromosomal, targeted chromosomal, and extra-chromosomal hypermutation approaches. It also compares various continuous evolution strategies based on different principles, providing a reference for selecting suitable methods for specific evolutionary goals. Furthermore, this review discusses the two primary limitations for further widespread application of in vivo continuous evolution, which are lack of general applicability and insufficient mutagenic capability. We envision that developing generally applicable mutagenic components and methods to enhance mutation rates for in vivo continuous evolution are promising future directions for wide range applications of continuous evolution.

Peripheral immune landscape of pediatric fulminant myocarditis revealed by single-cell sequencing

Abstract Fulminant myocarditis (FM) is one of the most feared diseases in children because of its fulminant nature and high mortality rate. However, the precise pathological immune subsets and molecular changes in FM are unknown. Here, we present the first comprehensive cellular and transcriptomic profiling of the peripheral blood mononuclear cells of children in FM acute and recovery phases using Single-cell RNA sequencing. 21 cell clusters are identified among 79542 cells. The proportion of T cells and NK cells increase, while myeloid cells and B cells reduce in acute phase, which were consistent with our flow cytometry data of 35 FM patients. Several unique cell types in peripheral blood are identified, including regulatory B cells, MAIT cells, adaptive NK cells and CD8+Tpex cells. The transcriptomic analysis exhibited elevated expression levels of chemokine receptor CXCR4 and S100A family genes almost in all cell types in FM acute phase, as well as MHC-II molecules in antigen-presenting cells. TCR and BCR exhibit remarkable amplification and obvious skewed usages of V genes in FM. Ligand receptor analysis show myeloid cells maintained active communication with other immune cells. Considering that CXCR4 may play an important role in myocarditis, we designed experiments to explore its function in mouse model. Vital myocarditis (VMC) mouse model was constructed using Coxsackie virus type3（CVB3）.We found that myocardial inflammation and myocardial injury of VMC mice were alleviated when treated with CXCR4 blocker. CXCR4 may be a potential therapeutic target for myocarditis. Our study will provide useful insights into key immune cell subsets and transcriptomic profiles implicated in pediatric fulminant myocarditis acute phase and recovery phase, thus providing several potential diagnostic and therapeutic targets for this disease.

The effects of fresh embryo transfer and frozen-thawed embryo transfer on the perinatal outcomes of single fetuses from mothers with PCOS.

To investigate the effects of fresh embryo transfer and frozen-thawed embryo transfer on perinatal outcomes among patients with PCOS. Patients who underwent in vitro fertilization and embryo transfer at the reproductive medicine center of the Affiliated Hospital of Guangdong Medical University from February 2013 to March 2021 were retrospectively analyzed. Patients were divided into the fresh embryo transfer group and frozen-thawed embryo transfer group according to whether fresh embryo transfer was performed. According to their conditions, patients were further classified into the ET-PCOS group (group A, n = 104), ET-non-PCOS group (group B, n = 212), FET-PCOS group (group C, n = 102), or FET-non-PCOS group (group D, n = 148); the general data, laboratory indicators and pregnancy outcomes of the patients were statistically analyzed, and the perinatal outcomes and related factors between the groups were compared and analyzed. The level of E2 on the HCG test day in the ET group was lower than that in the FET group. The natural birth rate of group D was lower than that of group A and group B, and the cesarean section rate was higher than that of group A and group B; the clinical pregnancy rate of group A was higher than that of group B and group D, and the difference was statistically significant (P < 0.05). There was no significant difference in the total abortion rate, early abortion rate or late abortion rate between the groups (P > 0.05). There was no significant difference in gestational age, neonatal sex or neonatal weight between the groups (P > 0.05). The incidence of placenta previa in Group B was significantly lower than that in Group D, and the difference was significant (P < 0.05). The incidence of fetal distress in Group B was significantly lower than that in Groups C and D, and the incidence of neonatal jaundice in Group D was significantly higher than that in Groups A and B (P < 0.05). In the multivariate analysis, the number of high-quality embryos was independent factors affecting clinical pregnancy, and the embryo transfer method was an independent factor affecting fetal distress and neonatal jaundice. Young PCOS patients without risk of OHSS have a high clinical pregnancy rate with fresh transplant cycles. PCOS disease itself has no significant effect on the perinatal outcomes of the mother or singleton infant. Frozen-thawed embryo transfer may increase the incidence of low placenta, fetal distress and neonatal jaundice.

Challenges and Strategies in the Industrial Application of Dendrobium officinale

Dendrobium officinale Kimura &amp; Migo (D. officinale) is a well-recognized traditional Chinese medicinal herb that is both medicinal and edible. Contemporary pharmacological studies have revealed that D. officinale contains abundant bioactive compounds, including polysaccharides, flavonoids, alkaloids, and dendrobine, exhibiting diverse pharmacological properties such as antioxidant, anti-inflammatory, and immunomodulatory effects. However, the industrial application of D. officinale faces many problems, such as the scarcity of wild resources, low natural reproduction rate, and slow growth rate as well as the lack of relevant industrial standards. Nevertheless, substantial advancements, including the exploitation of artificial propagation techniques and breeding of new varieties, have been achieved in recent years. These developments have effectively addressed the challenges associated with its low natural reproduction rate and the scarcity of wild resources. This review summarizes the progress in the industrial development, seedling cultivation, and pharmacological exploration of D. officinale in recent years. Furthermore, it analyzes current research inadequacies and offers strategic solutions to enhance its application in healthcare and medicine.

Microwave-treated layered graphite for highly efficient solar-powered seawater desalination and wastewater treatment

In the midst of the global water crisis, the ‘waste-to-treasure’ strategy, which includes desalination and wastewater recycling, is proving to be a promising approach. However, existing solar evaporators are hampered by challenges such as low photothermal conversion efficiency and significant heat losses. Here, we present an innovative solution that reduces the band gap of the material and improves the efficiency of light recycling. As a result, the microwave-treated graphite achieves a 15 % reduction in reflectivity and a 9 °C increase in surface temperature. In addition, the integration of this graphite with a hydrogel to modulate the interfacial wettability further optimizes the evaporation efficiency. When exposed to sunlight, the developed cone column evaporator achieves an impressive evaporation rate of 2.91 kg m−2 h−1, which is a significant increase of 663 % over the natural evaporation rate of a 3.5 wt% NaCl solution. Remarkably, no salt deposits were observed on the surface of the evaporator during the tests and the material exhibited excellent adsorption and desorption properties for pollutants, highlighting its potential for sustainable applications. These results provide valuable theoretical and practical insights for the design and development of high-efficiency solar evaporators.

The Impact of Different Thinning Regimes on the Growth Dynamics of Pure Norway Spruce Stands in Lithuania

Forest growth under changing environmental conditions has been a major concern worldwide. The estimations of forests’ growth trends may provide significant insight on changing the value of Norway spruce (Picea abies (L.) H. Karst.) forests. The purpose of this study was to estimate the growth dynamics of thinned and un-thinned spruce stands in Lithuania by assessing their standing volume, gross volume yield, and stand density. For this purpose, two pure Norway spruce sites, established in 1990 and 1992, were selected. The thinning treatment scheme for each trial, comprised of five distinct stand density variants and eight different yield parameters, were analysed for each plot. Control plots exhibited the smallest growth in diameter, whereas stands that had been thinned once at a young age displayed the largest diameter increment (peak—1.4 cm/year). An increasing trend in tree stem volume was registered in all thinning treatment plots. The greatest competition index was found in the control plots, indicating an exceptionally high competition (peak—4.6–5.1) between trees for growth space. The competition index was four times smaller (2.0) in the moderately thinned stand. Intensifying natural mortality rate and signs of growth stabilization in the control plots (un-thinned) cannot guarantee them the positions of the highest productivity and accumulated stand volume in the future compared with thinned spruce stands.

Occurrence and effect of dwarf mistletoe (Arceuthobium globosum and A. vaginatum) in high-elevation forests in México

Climate change has very important effects on high mountain forests (>3500 masl), which face various ecological problems associated with global change including the proliferation of pests and parasitic plants. These sensitive ecological systems cover approximately 39,000 ha of Mexican territory and occur around some of the highest volcanoes in the country. The objective of this research was to determine the spatial distribution and infestation levels of dwarf mistletoe (Arceuthobium spp.) in the main populations of Pinus hartwegii in five mountains of the Trans-Mexican Volcanic System (Pico de Orizaba, Nevado de Toluca, Cofre de Perote, Nevado de Colima and Monte Tláloc) and identify infestation patterns in relation to the structure of the forest. In the study, 2658 sampling sites (1000 m² each) were installed using the contour lines as access transects to the forest, distributed at every 100 of altitude, between 3500 and 4000 masl. Approximately 32 % of the sampled area had some level of attack by dwarf mistletoe, distributed across all diameter categories of the trees. The infestations affected the establishment of natural regeneration and rates of tree mortality.

Assessing the multifaceted repercussions of chemical insecticides on vegetable yield and human population: A modeling study

Vegetables stand out as invaluable reservoirs of essential vitamins, minerals, antioxidants, and vital dietary elements, yet their production faces a considerable threat due to insects. To tackle this challenge, farmers spray chemical insecticides to enhance vegetable yields by controlling the insect population. Nevertheless, the presence of insecticide residues in vegetables stands as a primary contributor to acute illnesses and chronic health conditions in humans. In the present research work, we formulate a novel nonlinear mathematical model meticulously designed to scrutinize the multifaceted repercussions of chemical insecticides on vegetable yield and the human population. In our model formulation, we adopt a dynamic approach where insecticide application on vegetables in agricultural fields correlates with the insect population. However, we acknowledge the consequential impact of insecticide usage on human health, which in turn reduces the growth rate of the human population. This study determines the critical value of the spraying rate of insecticide at which the human population reaches its maximum, ensuring that human needs for vegetables are met while minimizing the adverse effects of insecticide. Since various species of insects attack vegetables in the field and different insect species have different natural mortality rates, therefore we also identify the range of natural mortality rates of insects for which vegetable yield is minimal and fluctuates with time. Further, our research reveals that if the natural mortality rate of insects in a certain crop field lies within this identified range, then farmers should increase the insecticide spraying rate to avoid this upheaval situation and stabilize vegetable yield at a higher level.

Land Transformations in Irpinia (Southern Italy): A Tale on the Socio-Economic Dynamics Acting in a Marginal Area of the Mediterranean Europe

Marginal areas in economically advanced countries are a critical issue that European and national policies have been addressing for some time. These areas are affected by depopulation, infrastructural gaps and labor systems that do not reach the corresponding national levels and where often agriculture still plays a critical role. In Italy, despite the fact that the National Strategy for Inner Areas (SNAI) has been active for about a decade with the aim of increasing the territorial cohesion of these fragile areas, rather limited results have been achieved in terms of halting economic marginalization and demographic decline. In this specific context, our work is aimed at analyzing land use changes, the loss of ecosystem services and demographic trends in a Mediterranean region (Irpinia—Southern Italy) on district and municipal scales in the last 30 years (1990–2018) to capture current, subtle socio-economic dynamics. The analysis carried out has indicated a substantial increase in urban areas due to the development of new industrial areas and discontinuous urban fabric (urban sprawl) at the expense of natural areas (mainly meadows and shrublands). The agricultural areas have remained substantially unchanged in terms of extension, with a slight increase in heterogeneous agricultural areas and an expansion of high-value crops (vineyards), that are the most suitable for multifunctional agriculture activities (experiential and rural tourism). The analysis of the demographic trend has highlighted a widespread phenomenon of depopulation, with the exception of those municipalities who economically orbit around the provincial capital of Avellino. The municipalities in depopulation are mostly located in the inner areas characterized by a more rugged morphology and infrastructural gaps. Unexpectedly, most of municipalities show a significant anticorrelation among the population and agricultural areas which is an indicator of social and economic phenomena as complex as they are underestimated. As a final step, this analysis highlights also a loss of carbon storage mainly attributable to the soil sealing of large areas. This study can help to comprehensively understand the conditions of marginal areas in Mediterranean Europe over recent decades in the light of the main socio-economic dynamics to better direct efforts towards the containment of the human capital hemorrhage, consisting of persistently negative natural and migratory rates, and the sustainable empowerment of these geo-economic peripheries.

Geese as keystone species in the Low Arctic of central Canada: the Karrak Lake Research Station

True abundance of lesser snow ( Anser caerulescens caerulescens, Linnaeus 1758) and Ross's geese ( Anser rossii, Cassin 1861, collectively referred to as “light geese”, in North America had been unknown in the 1980s. However, different indices of abundance suggested steady increases at the time. The Karrak Lake Research Station (KLRS) was established partly because it was not known if the breeding biology from more southern latitudes (the only information available at the time) was representative of more northern colonies where 90% of the midcontinent population of lesser snow geese nested. Visits in 1990 confirmed the continued importance of Karrak Lake and surrounding areas in Canada’s central Arctic to a large nesting concentration of both snow and Ross's geese documented previously. Key activities at KLRS were (1) colony-wide annual monitoring of nesting goose abundance and nesting performance and (2) large-scale marking efforts to monitor survival, range-wide abundance, distribution, and exploitation rate from hunter harvest and natural mortality rate. The scope of research expanded to include their interaction with local vegetation and other sympatric wildlife, including Arctic foxes ( Vulpes lagopus, Linnaeus 1758), king eiders ( Somateria spectabilis, Linnaeus 1758), long-tailed ducks ( Clangula hyemalis, Linnaeus 1758), and cackling geese ( Branta hutchinsii). Following exponential growth in the 1990s and 2000s, nesting populations of light geese at Karrak lake collapsed since 2012, presenting a unique opportunity to examine how local ecosystems recover and revert from heavy grazing by hyperabundant geese.

Body composition and muscle composition phenotypes in patients on waitlist and shortly after liver transplant – results from a pilot study

BackgroundSarcopenia is common in end-stage liver disease and negatively impacts patients awaiting or undergoing liver transplantation (LT). Magnetic resonance imaging (MRI) may be used to measure body composition and sarcopenia. We aimed to evaluate the feasibility of MRI-based LT body composition profiling, describe waitlist body composition, and assess the natural rate of change in body composition while on the waitlist and post-LT.MethodsThis prospective pilot study recruited adults listed for LT at an urban, tertiary care facility. Eighteen participants were scanned at time of waitlisting and 15 had follow-up MRIs (waitlist and/or post-LT). An 8-min MRI was used to measure body composition (AMRA® Researcher) including thigh fat-free muscle volume (FFMV) and fat infiltration (MFI), visceral (VAT) and abdominal subcutaneous (ASAT) adipose tissue volumes, and liver fat. A sex- and BMI invariant FFMV z-score (z-FFMV) was calculated, and muscle composition (MC) phenotypes were defined using the muscle assessment score (consisting of the FFMV z-score and sex-adjusted MFI). Rate of body composition change was calculated using mixed-effect modelling and is presented as rate per 30 days.ResultsAt time of waitlisting, 73% of the 18 participants had high MFI and 39% had the adverse MC (low FFMV z-score and high MFI) phenotype. Seven participants received an LT. Post-LT serial MRIs, at a median of 147 days apart within the first 200 days post-LT, demonstrated increased z-FFMV 0.22 SDs/(30 days) (p = 0.002), VAT 0.23 (p < 0.001), and ASAT 0.52 (p = 0.001) L/(30 days), but no change in MFI (p = 0.200) nor liver fat (p = 0.232).ConclusionMRI-based body composition profiling is feasible in LT patients and shortly after LT. This can be amended to routine clinical scans and may help in early identification of patients who may benefit from interventions to improve body composition. In addition, body composition changes significantly over time after LT.

Mathematical Modelling of Spatially Inhomogeneous Non-Stationary Interaction of Pests with Transgenic and Non-Modified Crops Considering Taxis

Introduction. This paper addresses a unified spatially inhomogeneous, non-stationary model of interaction between genetically modified crop resources (corn) and the corn borer pest, which is also present on a relatively small section of non-modified corn. The model assumes that insect pests influence both types of crops and are capable of independent movement (taxis) towards the gradient of plant resources. It also considers diffusion processes in the dynamics of all components of the unified model, biomass growth, genetic characteristics of both types of plant resources, processes of crop consumption, phenomena of growth and degradation, diffusion, and mutation of pests. The model allows for predictive calculations aimed at reducing crop losses and increasing the resistance of transgenic crops to pests by slowing down the natural mutation rate of the pest. Materials and Methods. The mathematical model is an extension of Kostitsin’s model and is formulated as an initial-boundary value problem for a nonlinear system of convection-diffusion equations. These equations describe the spatiotemporal dynamics of biomass density changes in two types of crops — transgenic and non-modified — as well as the specific populations (densities) of three genotypes of pests (the corn borer) resulting from mutations. The authors linearized the convection-diffusion equations by applying a time-lag method on the time grid, with nonlinear terms from eachequation taken from the previous time layer. The terms describing taxis are presented in a symmetric form, ensuring the skew-symmetry of the corresponding continuous operator and, in the case of spatial grid approximation, the finite-difference operator. Results. A stable monotonic finite-difference scheme is developed, approximating the original problem with second-order accuracy on a uniform 2D spatial grid. Numerical solutions of model problems are provided, qualitatively corresponding to observed processes. Solutions are obtained for various ratios of modified and non-modified sections of the field. Discussion and Conclusion. The obtained results regarding pest behavior, depending on the type of taxis, could significantly extend the time for pests to acquire Bt resistance. The concentration dynamics of pests moving in the direction of the food gradient differs markedly from the concentration of pests moving towards a mate for reproduction.

Effect of rain shelter installation on the natural ventilation performance of monitor roofs

As a common means of building ventilation, monitor roofs have been employed to introduce indoor airflow via thermal buoyancy and/or wind. However, preventing rainwater from entering the room via the monitor roof has become an important practical issue. In this study, the effect of installing a rain shelter on the natural ventilation performance of a monitor roof was studied via computational fluid dynamics (CFD). The experimental monitor roof was 1.2 m in width and 1.2 m in height, with/without eave overhang. The results revealed that after rain shelter installation, a rain protection effect was achieved, and the ventilation rate increased because of flow structure conformity, with an overall average effectiveness of 1.02. The ventilation potential and the basic flow patterns corresponding to different design schemes were described in detail. Moreover, a correlation equation for the hybrid natural ventilation rate under the recommended design schemes was provided.

Night cooling by hybrid supply ventilation – analytical predictions of airflow rates and the ‘hybrid ventilation triangles’

Overheating in buildings can be mitigated during periods of excessively warm weather through the application of a night purge ventilation strategy. Building on the mathematical model of Waterson and Hunt (2024), we investigate the emerging field of hybrid ventilation – specifically the rates of airflow achieved by the simultaneous combination of ‘stack-driven’ natural displacement ventilation and a mechanical supply. Whilst the focus of Waterson and Hunt (2024) was specifically on predicting the time taken to complete a purge, herein we focus on airflow rates and in doing so elucidate the somewhat counter intuitive role that the mechanical supply has on the natural ventilation flow rates. Our results challenge the perception that a hybrid approach must be superior to both solely natural and mechanical strategies. Focusing on the variation in airflow rates during a hybrid purge, our model reveals: (i) a hybrid purge offers an improvement over a solely mechanical purge only during one of the two distinct flow regimes identified; and (ii) the manner in which the stack-driven and mechanical components combine is highly nuanced and cannot be predicted by the linear superposition of the constituent stack-driven and mechanical contributions.

Labour market skills, endogenous productivity and business cycles

This paper analyses how labour market heterogeneity affects unemployment, productivity and business cycle dynamics. To this aim, we set up a model with asymmetric search and matching frictions across skilled and unskilled workers, and endogenous productivity through R&D investment and intangible capital accumulation. Skill mismatch and skill-specific labour market institutions have three main effects on business cycles and growth dynamics. First, the relative scarcity of skilled workers increases the natural rate of unemployment and reduces total factor productivity with long-run effects on the growth rate of output. Second, skill heterogeneity in the labour market generates asymmetric outcomes and amplifies measures of employment, wages and consumption inequality. Finally, the model provides important insights for the Phillips and Beveridge curves. Incorporating skill heterogeneity leads to a flattening of the Phillips curve as wages and unemployment respond unevenly across skill types. Also, the model generates sideward shifts of the Beveridge curve following business cycle shocks, with the extent of these shifts depending on the degree of skill heterogeneity.