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17 pages, 242 KiB  
Article
The Nepalese Diaspora in Canada: History, Diasporic Experiences, and Contemporary Issues
by Subash Giri
Genealogy 2025, 9(1), 16; https://doi.org/10.3390/genealogy9010016 - 12 Feb 2025
Viewed by 2075
Abstract
Despite the Nepalese diaspora being a part of the South Asian diaspora in Canada—the largest fraction of Canadian diasporas—systematic investigations into and knowledge about the Nepalese diaspora is strikingly limited. The existing studies centred on the South Asian diaspora predominantly deal with the [...] Read more.
Despite the Nepalese diaspora being a part of the South Asian diaspora in Canada—the largest fraction of Canadian diasporas—systematic investigations into and knowledge about the Nepalese diaspora is strikingly limited. The existing studies centred on the South Asian diaspora predominantly deal with the Indian, Pakistani, Sri Lankan, and Bangladeshi diasporas and often homogenize the Nepalese diaspora with these diasporic groups. This study, as the first scholarly investigation into this group, examines the emerging and fast-growing Nepalese diasporic community in Canada. Based on government data, reports, and in-depth semi-structured interviews, this article presents the history of the Nepalese diaspora in Canada. It also delineates their diasporic experiences as they arrive and embark on a new journey to Canada and some contemporary socio-cultural and intergenerational issues that have arisen in this diasporic community. The article finds a rapid growth in the Nepalese diaspora in about the last two decades. It identifies the quest for a better life, health care, social security, children’s education, and escape from political turmoil and instability in their native country as the chief reasons for this influx of Nepalese in Canada. The article also uncovers dramatic career shifts, adaptation or settlement-related strains, longing for homeland, cultural decline, and growing intergenerational gaps as the key post-immigration challenges encountered by the Nepalese diaspora in Canada. Full article
(This article belongs to the Special Issue Tracking Asian Diasporic Experiences)
15 pages, 2662 KiB  
Article
The Gender-Biased Differential Effect of KDM6A Mutation on Immune Therapy in Urothelial Carcinoma: A Public Database Study
by Yohei Sekino, Hikaru Nakahara, Kenichiro Ikeda, Kohei Kobatake, Yuki Kohada, Ryo Tasaka, Kenshiro Takemoto, Shunsuke Miyamoto, Hiroyuki Kitano, Keisuke Goto, Akihiro Goriki, Keisuke Hieda and Nobuyuki Hinata
Cancers 2025, 17(3), 356; https://doi.org/10.3390/cancers17030356 - 22 Jan 2025
Viewed by 1147
Abstract
Background/Objectives: It is said that genes that escape from X chromosome inactivation (XCI) contribute to gender differences. We analyzed the prognostic role of these genes and identified a gender-biased difference in prognosis according to KDM6A mutation in the immune therapy cohort (IMvigor [...] Read more.
Background/Objectives: It is said that genes that escape from X chromosome inactivation (XCI) contribute to gender differences. We analyzed the prognostic role of these genes and identified a gender-biased difference in prognosis according to KDM6A mutation in the immune therapy cohort (IMvigor 210). We also investigate the gender-biased differential effect of KDM6A mutation in several public databases of urothelial carcinoma (UC). Methods: We used AACR GENIE, The Cancer Genome Atlas, International Cancer Genome Consortium, several public databases related to immune therapy, chemotherapy, and BCG treatment. We studied the gender-biased prognostic role of KDM6A mutation in several cohorts and the association between KDM6A mutation and immune-related fractions according to gender. Results: The expression of KDM6A was higher in females than in males in several cohorts. Mutation of KDM6A was observed in about 20–25% of the patients. The rate of KDM6A mutation was higher in females than in males in several cohorts. Kaplan–Meier analysis revealed a gender-biased difference in prognosis between patients with KDM6A mutations and those with the wild-type KDM6A in several cohorts, including the immune therapy cohort. The rate of immune-inflamed type was higher in males than in females in the patients with KDM6A mutation in the IMvigor 210 and UC-GENOME studies. Single-sample Gene Set Enrichment Analysis showed that CD8+ cells and type 1 IFN response fractions and APC co-inhibition fraction were higher in the male than female patients with KDM6A mutation. Similar findings were observed in other immune-related studies (UC-GENOME). Conclusions: The effect of KDM6A mutation on immune therapy varied according to gender, and the status of KDM6A mutation may be a promising biomarker in immune therapy in UC. Full article
(This article belongs to the Special Issue Clinical Treatment and Prognostic Factors of Urologic Cancer)
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15 pages, 2091 KiB  
Article
High-Throughput Screening System Evaluation of Andrographis paniculata (Burm.f.) Extracts and Their Fractions against Mosquito Vectors
by Patcharawan Sirisopa, Theerachart Leepasert, Thitinun Karpkird, Jirod Nararak, Kanutcharee Thanispong, Alex Ahebwa and Theeraphap Chareonviriyaphap
Insects 2024, 15(9), 712; https://doi.org/10.3390/insects15090712 - 18 Sep 2024
Cited by 1 | Viewed by 1542
Abstract
Infectious diseases that cause illness and/or death in humans can be contracted from mosquito bites. A viable and alternate method of personal protection that can lower the danger of human exposure to mosquito-borne diseases is the use of plant-based repellents. Using a high-throughput [...] Read more.
Infectious diseases that cause illness and/or death in humans can be contracted from mosquito bites. A viable and alternate method of personal protection that can lower the danger of human exposure to mosquito-borne diseases is the use of plant-based repellents. Using a high-throughput screening system, the current work examined the toxicity, contact irritancy, and spatial repellency of Andrographis paniculata crude extract and its fractions against Aedes aegypti, Anopheles minimus, and An. dirus. Five fractions (i.e., F1, F2, F3, F4, and F5) were separated from the crude extract by column and thin layer chromatography and analyzed using high-performance liquid chromatography and mass spectrometry. The major active compounds identified from F3 and F5 were 4-deoxy-11,12-didehydroandrographolide and andrographolide. Three concentrations (1.0, 2.5, and 5.0%) for each of the crude extracts and the five fractions were individually impregnated on nylon netting strips and evaluated against the three mosquito species. Results showed that the highest contact irritancy was elicited by the crude extract at 5% concentration against Ae. aegypti (43.70% escaped). Results of the spatial activity index (SAI) showed that fractions F3 and F5 at 2.5% demonstrated the strongest repellency against Ae. aegypti (SAI = 0.84) and An. minimus (SAI = 0.83), respectively. Both the crude extract and its components did not cause any knockdown or mortality. These findings suggest that fractionation of A. paniculata extracts is valuable in assessing their spatial repellent efficacy against mosquitoes. Fractions F3 and F5 hold promise as natural mosquito repellents and could contribute to developing effective mosquito control strategies. Full article
(This article belongs to the Section Medical and Livestock Entomology)
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15 pages, 9688 KiB  
Article
Effect of Vibration Pretreatment–Microwave Curing Process Parameters on the Mechanical Performance of Resin-Based Composites
by Dechao Zhang, Lihua Zhan, Bolin Ma, Jinzhan Guo, Wentao Jin, Xin Hu, Shunming Yao and Guangming Dai
Polymers 2024, 16(17), 2518; https://doi.org/10.3390/polym16172518 - 4 Sep 2024
Cited by 3 | Viewed by 1354
Abstract
The vibration pretreatment–microwave curing process can achieve high-quality molding under low-pressure conditions and is widely used in the curing of resin-based composites. This study investigated the effects of the vibration pretreatment process parameters on the void content and the fiber weight fraction of [...] Read more.
The vibration pretreatment–microwave curing process can achieve high-quality molding under low-pressure conditions and is widely used in the curing of resin-based composites. This study investigated the effects of the vibration pretreatment process parameters on the void content and the fiber weight fraction of T700/TRE231; specifically, their influence on the interlaminar shear strength and impact strength of the composite. Initially, an orthogonal experimental design was employed with interlaminar shear strength as the optimization target, where vibration acceleration was determined as the primary factor and dwell time as the secondary factor. Concurrently, thermogravimetric analysis (TGA) was performed based on process parameters that corresponded to the extremum of interlaminar shear strength, revealing a 2.17% difference in fiber weight fraction among specimens with varying parameters, indicating a minimal effect of fiber weight fraction on mechanical properties. Optical digital microscope (ODM) analysis identified interlaminar large-size voids in specimens treated with vibration energy of 5 g and 15 g, while specimens subjected to a vibration energy of 10 g exhibited numerous small-sized voids within layers, suggesting that vibration acceleration influences void escape pathways. Finally, impact testing revealed the effect of the vibration pretreatment process parameters on the impact strength, implying a positive correlation between interlaminar shear strength and impact strength. Full article
(This article belongs to the Special Issue Advances in Functional Polymers and Composites)
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19 pages, 2402 KiB  
Article
Dynamical Properties of Perturbed Hill’s System
by Mohammed K. Ibrahim, Taha Rabeh and Elbaz I. Abouelmagd
Math. Comput. Appl. 2024, 29(4), 66; https://doi.org/10.3390/mca29040066 - 19 Aug 2024
Cited by 4 | Viewed by 1873
Abstract
In this work, some dynamical properties of Hill’s system are studied under the effect of continued fraction perturbation. The locations and kinds of equilibrium points are identified, and it is demonstrated that these points are saddle points and the general motion in their [...] Read more.
In this work, some dynamical properties of Hill’s system are studied under the effect of continued fraction perturbation. The locations and kinds of equilibrium points are identified, and it is demonstrated that these points are saddle points and the general motion in their proximity is unstable. Furthermore, the curves of zero velocity and the regions of possible motion are defined at different Jacobian constant values. It is shown that the regions of forbidden motion increase with increasing Jacobian constant values and there is a noticeable decrease in the permissible regions of motion, leading to the possibility that the body takes a path far away from the primary body and escapes to take an unknown trajectory. Furthermore, the stability of perturbed motion is analyzed from the perspective of a linear sense, and it is observed that the linear motion is also unstable. Full article
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20 pages, 2254 KiB  
Article
Monitoring of Wheat Stripe Rust Using Red SIF Modified by Pseudokurtosis
by Xia Jing, Qixing Ye, Bing Chen, Bingyu Li, Kaiqi Du and Yiyang Xue
Agronomy 2024, 14(8), 1698; https://doi.org/10.3390/agronomy14081698 - 1 Aug 2024
Viewed by 1114
Abstract
Red solar-induced chlorophyll fluorescence (SIFB) is closely related to the photosynthetically active radiation absorbed by chlorophyll. The scattering and reabsorption of SIFB by the vegetation canopy significantly change the spectral intensity and shape of SIF, which affects the relationship between [...] Read more.
Red solar-induced chlorophyll fluorescence (SIFB) is closely related to the photosynthetically active radiation absorbed by chlorophyll. The scattering and reabsorption of SIFB by the vegetation canopy significantly change the spectral intensity and shape of SIF, which affects the relationship between SIF and crop stress. To address this, we propose a method of modifying SIFB using SIF spectral shape characteristic parameters to reduce this influence. A red pseudokurtosis (PKB) parameter that can characterize spectral shape features was calculated using full-spectrum SIF data. On this basis, we analyzed the photosynthetic physiological mechanism of PKB and found that it significantly correlates with both the fraction of photosynthetically active radiation absorbed by chlorophyll(fPARchl) and the red SIF escape rate (fesc680); thus, it is closely related to the scattering and reabsorption of SIFB by the vegetation canopy. Consequently, we constructed an expression of PKB to modify SIFB. To evaluate the modified SIFB (MSIFB) in monitoring the severity of wheat stripe rust, we analyzed the correlations between SIFB, MSIFB, SIFB-VIs (a fusion of the vegetation index and SIFB), and MSIFB-VIs (a fusion of the vegetation index and MSIFB) with the severity level (SL), respectively. The results show that the correlation between MSIFB and the severity of wheat stripe rust increased by an average of 25.6% and at least 16.95% compared with that for SIFB. In addition, we constructed remote sensing monitoring models for wheat stripe rust using linear regression methods, with SIFB, MSIFB, SIFB-VIs, and MSIFB-VIs as independent variables. PKB significantly improves the accuracy and robustness of models based on SIFB and its fusion index SIFB-VIs in the constructed testing set. The R-value between the predicted SL and the measured SL of the remote sensing monitoring model for wheat stripe rust was established using MSIFB-VIs as the independent variable, and it was improved by an average of 39.49% compared with the model using SIFB-VIs. The RMSE was reduced by an average of 18.22%. Therefore, the SIFB modified by PKB can weaken the effects of chlorophyll reabsorption and canopy architecture on SIFB and improve the ability of SIFB to detect stress information. Full article
(This article belongs to the Section Pest and Disease Management)
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19 pages, 6530 KiB  
Article
Visualization and Quantification of Facemask Leakage Flows and Interpersonal Transmission with Varying Face Coverings
by Xiuhua Si, Jensen S. Xi, Mohamed Talaat, Jay Hoon Park, Ramaswamy Nagarajan, Michael Rein and Jinxiang Xi
Fluids 2024, 9(7), 166; https://doi.org/10.3390/fluids9070166 - 22 Jul 2024
Cited by 3 | Viewed by 1557
Abstract
Although mask-wearing is now widespread, the knowledge of how to quantify or improve their performance remains surprisingly limited and is largely based on empirical evidence. The objective of this study was to visualize the expiratory airflows from facemasks and evaluate aerosol transmission between [...] Read more.
Although mask-wearing is now widespread, the knowledge of how to quantify or improve their performance remains surprisingly limited and is largely based on empirical evidence. The objective of this study was to visualize the expiratory airflows from facemasks and evaluate aerosol transmission between two persons. Different visualization methods were explored, including the Schlieren optical system, laser/LED-particle imaging system, thermal camera, and vapor–SarGel system. The leakage flows and escaped aerosols were quantified using a hotwire anemometer and a particle counter, respectively. The results show that mask-wearing reduces the exhaled flow velocity from 2~4 m/s (with no facemask) to around 0.1 m/s, thus decreasing droplet transmission speeds. Cloth, surgical, and KN95 masks showed varying leakage flows at the nose top, sides, and chin. The leakage rate also differed between inhalation and exhalation. The neck gaiter has low filtration efficiency and high leakage fractions, providing low protection efficiency. There was considerable deposition in the mouth–nose area, as well as the neck, chin, and jaw, which heightened the risk of self-inoculation through spontaneous face-touching. A face shield plus surgical mask greatly reduced droplets on the head, neck, and face, indicating that double face coverings can be highly effective when a single mask is insufficient. The vapor–SarGel system provided a practical approach to study interpersonal transmission under varying close contact scenarios or with different face coverings. Full article
(This article belongs to the Special Issue Flow Visualization: Experiments and Techniques)
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10 pages, 267 KiB  
Article
Estimate for the Neutrino Magnetic Moment from Pulsar Kick Velocities Induced at the Birth of Strange Quark Matter Neutron Stars
by Alejandro Ayala, Santiago Bernal-Langarica and Daryel Manreza-Paret
Universe 2024, 10(7), 301; https://doi.org/10.3390/universe10070301 - 20 Jul 2024
Cited by 4 | Viewed by 1273
Abstract
We estimate the magnetic moment of electron neutrinos by computing the neutrino chirality flip rate that can occur in the core of a strange quark matter neutron star at birth. We show that this process allows neutrinos to anisotropically escape, thus inducing the [...] Read more.
We estimate the magnetic moment of electron neutrinos by computing the neutrino chirality flip rate that can occur in the core of a strange quark matter neutron star at birth. We show that this process allows neutrinos to anisotropically escape, thus inducing the star kick velocity. Although the flip from left- to right-handed neutrinos is assumed to happen in equilibrium, the no-go theorem does not apply because right-handed neutrinos do not interact with matter and the reverse process does not happen, producing the loss of detailed balance. For simplicity, we model the star core as consisting of strange quark matter. We find that even when the energy released in right-handed neutrinos is a small fraction of the total energy released in left-handed neutrinos, the process describes kick velocities for natal conditions, which are consistent with the observed ones and span the correct range of radii, temperatures and chemical potentials for typical magnetic field intensities. The neutrino magnetic moment is estimated to be μν3.6×1018μB, where μB is the Bohr magneton. This value is more stringent than the bound found for massive neutrinos in a minimal extension of the standard model. Full article
(This article belongs to the Special Issue Studies in Neutron Stars)
28 pages, 5481 KiB  
Article
A Proportional-Integral-One Plus Double Derivative Controller-Based Fractional-Order Kepler Optimizer for Frequency Stability in Multi-Area Power Systems with Wind Integration
by Mohammed H. Alqahtani, Sulaiman Z. Almutairi, Ali S. Aljumah, Abdullah M. Shaheen, Ghareeb Moustafa and Attia A. El-Fergany
Fractal Fract. 2024, 8(6), 323; https://doi.org/10.3390/fractalfract8060323 - 29 May 2024
Cited by 7 | Viewed by 1396
Abstract
This study proposes an enhanced Kepler Optimization (EKO) algorithm, incorporating fractional-order components to develop a Proportional-Integral-First-Order Double Derivative (PI–(1+DD)) controller for frequency stability control in multi-area power systems with wind power integration. The fractional-order element facilitates efficient information and past experience sharing among [...] Read more.
This study proposes an enhanced Kepler Optimization (EKO) algorithm, incorporating fractional-order components to develop a Proportional-Integral-First-Order Double Derivative (PI–(1+DD)) controller for frequency stability control in multi-area power systems with wind power integration. The fractional-order element facilitates efficient information and past experience sharing among participants, hence increasing the search efficiency of the EKO algorithm. Furthermore, a local escaping approach is included to improve the search process for avoiding local optimization. Applications were performed through comparisons with the 2020 IEEE Congress on Evolutionary Computation (CEC 2020) benchmark tests and applications in a two-area system, including thermal and wind power. In this regard, comparisons were implemented considering three different controllers of PI, PID, and PI–(1+DD) designs. The simulations show that the EKO algorithm demonstrates superior performance in optimizing load frequency control (LFC), significantly improving the stability of power systems with renewable energy systems (RES) integration. Full article
(This article belongs to the Special Issue Fractional Modelling, Analysis and Control for Power System)
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19 pages, 5128 KiB  
Article
A Comprehensive Description of the Anatomy and Histochemistry of Psychotria capillacea (Müll. Arg.) Standl. and an Investigation into Its Anti-Inflammatory Effects in Mice and Role in Scopolamine-Induced Memory Impairment
by Anelise Samara Nazari Formagio, Wagner Vilegas, Cândida Aparecida Leite Kassuya, Valter Paes De Almeida, Jane Manfron, Elisabete Castelon Konkiewitz, Edward Benjamin Ziff, Janaine Alberto Marangoni Faoro, Jessica Maurino Dos Santos, Ana Julia Cecatto, Maria Helena Sarragiotto and Rosilda Mara Mussury
Pharmaceuticals 2024, 17(5), 564; https://doi.org/10.3390/ph17050564 - 28 Apr 2024
Viewed by 1825
Abstract
Species of the genus Psychotria are used in popular medicine for pain, inflammatory symptoms, and mental disorders. Psychotria capillacea (Müll. Arg.) Standl. (Rubiaceae) is commonly known as coffee and some scientific studies have demonstrated its therapeutic potential. The goal of this study was [...] Read more.
Species of the genus Psychotria are used in popular medicine for pain, inflammatory symptoms, and mental disorders. Psychotria capillacea (Müll. Arg.) Standl. (Rubiaceae) is commonly known as coffee and some scientific studies have demonstrated its therapeutic potential. The goal of this study was to investigate the anti-inflammatory and neuroprotective effects, and acetylcholinesterase (AChE) inhibitory activity of a methanolic extract obtained from leaves of P. capillacea (MEPC), as well as the micromorphology and histochemistry of the leaves and stems of this plant. In addition, the MEPC was analyzed by UHPLC-MS/MS and the alkaloidal fraction (AF) obtained from the MEPC was tested in a mouse model of inflammation. MEPC contained three indole alkaloids, one sesquiterpene (megastigmane-type) and two terpene lactones. MEPC (3, 30 and 100 mg/kg) and AF (3 and 30 mg/kg) were evaluated in inflammation models and significantly inhibited edema at 2 h and 4 h, mechanical hyperalgesia after 4 h and the response to cold 3 h and 4 h after carrageenan injection. Scopolamine significantly increased the escape latency, and reduced the swimming time and number of crossings in the target quadrant and distance, while MEPC (3, 30 and 100 mg/kg), due to its neuroprotective actions, reversed these effects. AChE activity was significantly decreased in the cerebral cortex (52 ± 3%) and hippocampus (60 ± 3%), after MEPC administration. Moreover, micromorphological and histochemical information was presented, to aid in species identification and quality control of P. capillacea. The results of this study demonstrated that P. capillacea is an anti-inflammatory and antihyperalgesic agent that can treat acute disease and enhance memory functions in mouse models. Full article
(This article belongs to the Section Natural Products)
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16 pages, 8033 KiB  
Article
Thermo-Mechano-Chemical Processing of Printed Circuit Boards for Organic Fraction Removal
by Sergey M. Frolov, Viktor A. Smetanyuk, Anton S. Silantiev, Ilias A. Sadykov, Fedor S. Frolov, Jaroslav K. Hasiak, Alexey A. Shiryaev and Vladimir E. Sitnikov
Waste 2024, 2(2), 153-168; https://doi.org/10.3390/waste2020009 - 15 Apr 2024
Cited by 1 | Viewed by 2007
Abstract
Printed circuit boards (PCBs) are the main components of e-waste. In order to reduce the negative impact of waste PCBs on human health and the environment, they must be properly disposed of. A new method is demonstrated for recycling waste PCBs. It is [...] Read more.
Printed circuit boards (PCBs) are the main components of e-waste. In order to reduce the negative impact of waste PCBs on human health and the environment, they must be properly disposed of. A new method is demonstrated for recycling waste PCBs. It is referred to as the high-temperature thermo-mechano-chemical gasification (TMCG) of PCBs by the detonation-born gasification agent (GA), which is a blend of H2O and CO2 heated to a temperature above 2000 °C. The GA is produced in a pulsed detonation gun (PDG) operating on a near-stoichiometric methane–oxygen mixture. The PDG operates in a pulsed mode producing pulsed supersonic jets of GA and pulsed shock waves possessing a huge destructive power. When the PDG is attached to a compact flow reactor filled with waste PCBs, the PCBs are subject to the intense thermo-mechano-chemical action of both strong shock waves and high-temperature supersonic jets of GA in powerful vortical structures established in the flow reactor. The shock waves grind waste PCBs into fine particles, which undergo repeated involvement and gasification in the high-temperature vortical structures of the GA. Demonstration experiments show full (above 98%) gasification of the 1 kg batch of organic matter in a setup operation time of less than 350 s. The gaseous products of PCB gasification are mainly composed of CO2, CO, H2, N2, and CH4, with the share of flammable gas components reaching about 45 vol%. The solid residues appear in the form of fine powder with visible metal inclusions of different sizes. All particles in the powder freed from the visible metal inclusions possess a size less than 300–400 μm, including a large fraction of sizes less than 100 μm. The powder contains Sn, Pb, Cu, Ni, Fe, In, Cd, Zn, Ca, Si, Al, Ti, Ni, and Cl. Among these substances, Sn (10–20 wt%), Pb (5–10 wt%), and Cu (up to 1.5 wt%) are detected in the maximum amounts. In the powder submitted for analysis, precious elements Ag, Au, and Pt are not detected. Some solid mass (about 20 wt% of the processed PCBs) is removed from the flow reactor with the escaping gas and is partly (about 10 wt%) trapped by the cyclones in the exhaust cleaning system. Metal inclusions of all visible sizes accumulate only in the flow reactor and are not detected in powder samples extracted from the cyclones. The gasification degree of the solid residues extracted from the cyclones ranges from 76 to 91 wt%, i.e., they are gasified only partly. This problem will be eliminated in future work. Full article
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15 pages, 5180 KiB  
Article
Insights into Canopy Escape Ratio from Canopy Structures: Correlations Uncovered through Sentinel-2 and Field Observation
by Junghee Lee, Jungho Im, Joongbin Lim and Kyungmin Kim
Forests 2024, 15(4), 665; https://doi.org/10.3390/f15040665 - 7 Apr 2024
Cited by 1 | Viewed by 1456
Abstract
This study explores the quantitative relationship between canopy structure and the canopy escape ratio (fesc), measured as the ratio of near-infrared reflectance of vegetation (NIRv) to the fraction of absorbed photosynthetically active radiation (fAPAR). We analyzed the correlation between fesc [...] Read more.
This study explores the quantitative relationship between canopy structure and the canopy escape ratio (fesc), measured as the ratio of near-infrared reflectance of vegetation (NIRv) to the fraction of absorbed photosynthetically active radiation (fAPAR). We analyzed the correlation between fesc and key indicators of canopy structure—specifically, leaf area index (LAI) and clumping index (CI)—utilizing both Sentinel-2 satellite data and in situ observations. Our analysis revealed a moderate correlation between fesc and LAI, evidenced by an R2 value of 0.37 for satellite-derived LAI, which contrasts with the lower correlation (R2 of 0.15) observed with field-measured LAI. Conversely, the relationship between fesc and CI proved to be significantly weaker (R2 < 0.1), indicating minimal interaction between foliage distribution and light escape at the canopy level. This disparity in correlation strength was further evidenced in time series analysis, which showed little phenological variation in fesc compared to LAI. Our findings elucidate the complexities of estimating fesc based on the NIRv to fAPAR ratio and underscore the need for advanced methodologies in future research to enhance the accuracy of canopy escape models. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
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21 pages, 2026 KiB  
Article
Constraining the Initial Mass Function in the Epoch of Reionization from Astrophysical and Cosmological Data
by Andrea Lapi, Giovanni Gandolfi, Lumen Boco, Francesco Gabrielli, Marcella Massardi, Balakrishna S. Haridasu, Carlo Baccigalupi, Alessandro Bressan and Luigi Danese
Universe 2024, 10(3), 141; https://doi.org/10.3390/universe10030141 - 13 Mar 2024
Cited by 4 | Viewed by 1997
Abstract
We aim to constrain the stellar initial mass function (IMF) during the epoch of reionization. To this purpose, we build up a semi-empirical model for the reionization history of the Universe based on various ingredients: the latest determination of the UV galaxy luminosity [...] Read more.
We aim to constrain the stellar initial mass function (IMF) during the epoch of reionization. To this purpose, we build up a semi-empirical model for the reionization history of the Universe based on various ingredients: the latest determination of the UV galaxy luminosity function from JWST out to redshift z12; data-inferred and simulation-driven assumptions on the redshift-dependent escape fraction of ionizing photons from primordial galaxies; a simple yet flexible parameterization of the IMF ϕ(m)mξem,c/m in terms of a high-mass end slope ξ<0 and a characteristic mass m,c, below which a flattening or a bending sets in (allowing description of a variety of IMF shapes from the classic Salpeter to top-heavy ones); the PARSEC stellar evolution code to compute the UV and ionizing emission from different stars’ masses as a function of age and metallicity; and a few physical constraints related to stellar and galaxy formation in faint galaxies at the reionization redshifts. We then compare our model outcomes with the reionization observables from different astrophysical and cosmological probes and perform Bayesian inference on the IMF parameters via a standard MCMC technique. We find that the IMF slope ξ is within the range from 2.8 to 2.3, consistent with direct determination from star counts in the Milky Way, while appreciably flatter slopes are excluded at great significance. However, the bestfit value of the IMF characteristic mass m,c∼a few M implies a suppression in the formation of small stellar masses at variance with the IMF in the local Universe. This may be induced by the thermal background of ∼20–30 K provided by CMB photons at the reionization redshifts. We check that our results are robust against different parameterizations for the redshift evolution of the escape fraction. Finally, we investigate the implications of our reconstructed IMF for the recent JWST detections of massive galaxies at and beyond the reionization epoch, showing that any putative tension with the standard cosmological framework is substantially alleviated. Full article
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15 pages, 2756 KiB  
Article
Epigenetic and Transcriptional Shifts in Human Neural Stem Cells after Reprogramming into Induced Pluripotent Stem Cells and Subsequent Redifferentiation
by Carolin Haubenreich, Michael Lenz, Andreas Schuppert, Michael Peitz, Philipp Koch, Martin Zenke and Oliver Brüstle
Int. J. Mol. Sci. 2024, 25(6), 3214; https://doi.org/10.3390/ijms25063214 - 12 Mar 2024
Viewed by 2184
Abstract
Induced pluripotent stem cells (iPSCs) and their derivatives have been described to display epigenetic memory of their founder cells, as well as de novo reprogramming-associated alterations. In order to selectively explore changes due to the reprogramming process and not to heterologous somatic memory, [...] Read more.
Induced pluripotent stem cells (iPSCs) and their derivatives have been described to display epigenetic memory of their founder cells, as well as de novo reprogramming-associated alterations. In order to selectively explore changes due to the reprogramming process and not to heterologous somatic memory, we devised a circular reprogramming approach where somatic stem cells are used to generate iPSCs, which are subsequently re-differentiated into their original fate. As somatic founder cells, we employed human embryonic stem cell-derived neural stem cells (NSCs) and compared them to iPSC-derived NSCs derived thereof. Global transcription profiling of this isogenic circular system revealed remarkably similar transcriptomes of both NSC populations, with the exception of 36 transcripts. Amongst these we detected a disproportionately large fraction of X chromosomal genes, all of which were upregulated in iPSC-NSCs. Concurrently, we detected differential methylation of X chromosomal sites spatially coinciding with regions harboring differentially expressed genes. While our data point to a pronounced overall reinstallation of autosomal transcriptomic and methylation signatures when a defined somatic lineage is propagated through pluripotency, they also indicate that X chromosomal genes may partially escape this reinstallation process. Considering the broad application of iPSCs in disease modeling and regenerative approaches, such reprogramming-associated alterations in X chromosomal gene expression and DNA methylation deserve particular attention. Full article
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18 pages, 3411 KiB  
Article
Oxygen Isotope Fractionation Due to Non-Thermal Escape of Hot O from the Atmosphere of Mars
by James R. Lyons
Atmosphere 2024, 15(3), 292; https://doi.org/10.3390/atmos15030292 - 27 Feb 2024
Viewed by 1529
Abstract
Secondary minerals in SNC meteorites from Mars exhibit O isotope ratios believed to be consistent with the non-thermal escape of O from the atmosphere. The primary source of the non-thermal O is the dissociative- recombination of O2+ in the ionosphere. I [...] Read more.
Secondary minerals in SNC meteorites from Mars exhibit O isotope ratios believed to be consistent with the non-thermal escape of O from the atmosphere. The primary source of the non-thermal O is the dissociative- recombination of O2+ in the ionosphere. I present here the results of a model that accounts for the probability of escape of non-thermal O isotopes due to collisions with overlying CO2, combined with a model for Rayleigh fractionation of the atmosphere remaining as a result of O escape. Previous analyses of MAVEN number density data have shown a strong variability with latitude and season of the heights of the homopause and exobase, with a mean homopause at 110 km and a mean difference of about 60 km. Rayleigh model results demonstrate a dependence on homopause height and on temperature profile and require a more accurate calculation of fractionation factors for the Rayleigh equation. Isothermal temperature profiles yield much smaller variation in 17O with homopause height. These results demonstrate the need for a careful assessment of O isotope enrichment due to non-thermal escape both for the modern atmosphere and for the evolution of the atmosphere over the age of the planet. Full article
(This article belongs to the Section Planetary Atmospheres)
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