bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors influencing population growth in a bobcat population
Authors: Lehman Chadwick P. , Morrison Erin E. , Neiles Brady Y. , Rota Christopher T. 
Published: February 2024

AbstractBobcats (Lynx rufus) are the most broadly distributed native felid in North America and have substantial ecological and economic importance. Despite this importance, little is known about factors influencing population dynamics of this cryptic carnivore. Given recent apparent declines in abundance, we investigated population growth rate (λ) for a bobcat population in the Black Hills, South Dakota, USA, 2016–2022. We constructed and evaluated a females‐only matrix population model. Our estimate of asymptotic λ, derived from estimates of vital rates obtained over 6 years, was 0.85 (95% CI = 0.72, 1.02), which indicates that the vital rates in 2016–2022 were inadequate to sustain the population. Elasticity and sensitivity values were highest for changes in adult survival probability followed by, in order, changes in kitten and juvenile survival and adult reproductive contribution. Life‐stage simulation analysis also supported that adult survival was most important; however, the juvenile survival (91 day–1 year) component of a bobcat's first year of life was also important and a stronger influence on population growth than the kitten survival (first 90 days) component. For the combination of survival and reproductive rates we estimated positive population growth required either annual adult survival >0.85 or 275‐day juvenile survival >0.35, regardless of other vital rates. When assuming a baseline harvest rate of 23.5%, reducing the harvest rate to 9% led to a positive mean growth rate and a >0.50 probability of a growing population. Monitoring juvenile‐to‐adult harvest ratios can provide an indicator of age structure in the population, and we recommend restricting harvest when that ratio falls below 10%, particularly when managers lack research information on population growth.
Knowledge as a capability to make decisions: Experiences with a virtual support context
Authors: Kivijärvi Hannu 
Published: February 2024

AbstractHuman decision making is an act or process that is based on explicit or tacit knowledge, and can be supported in a limitless number of ways. Knowledge is a broad and delicate concept, rich in nuance, a concept that has been interpreted, understood, and categorized in different ways. Even if it may be true that “all knowing is personal knowing,” all knowledge is not inevitably personal knowledge. Organizations have a common capability to act (i.e., knowledge capacity or intellectual capital), the lack of which would inevitably prevent organizational action and would lead to unpredictability, disorder and chaos. Hence, the conversion of personal knowledge to organizational usage has become an important and justified stream of research. However, there are serious conceptual barriers to deriving organizational knowledge directly from personal knowledge. Although the term “conversion” is partly misleading, it is used here in the absence of a better alternative to describe a type of knowledge generation process in which one kind of knowledge is used to create another kind of knowledge. In this paper, we define knowledge as the individual or organizational capability to make decisions. We show that the ability to make decisions is determined not only by the personal dimension but also by the social and material dimensions; knowledge is a triangular model that combines these three worlds. In order to explore and manage the resource of knowledge more effectively in organizational contexts, the key question involves how to support and stimulate the deployment of personal knowledge for common usage in organizational decision making. The contributions of this paper are firstly the provision of a theoretical basis for a virtual support context, and secondly a description of an experience with a concrete virtual context that supports and stimulates the conversion of personal knowledge into strategic, organizational decisions. The support system developed here provides a set of virtual conditions that can be used to exercise organizational skills and capabilities for effective decision making.
Effect of stand age on soil microbial metabolic limitation and enzyme activities in Robinia pseudoacacia L. plantations in the loess hilly‐gully region, China
Authors: Zhao Min , Sun Yarong , Liu Shaohua , Li Yichun , Chen Yunming 
Published: February 2024

AbstractSoil heterotrophic microorganisms play crucial roles in soil biogeochemical cycles by secreting extracellular enzymes, but their metabolism is often limited by resource availability. Identifying major resources that limit soil microbial metabolism could help to create reasonable management practices for the maintenance of ecosystem function. Robinia pseudoacacia plantations perform crucial functions in reconstituting the ecological integrity of disturbed ecosystems; however, soil microbial metabolic limitations in R. pseudoacacia plantations remain poorly understood. Herein, R. pseudoacacia plantations of four age classes (10, 22, 37, and 47 years old) were sampled in the loess hilly‐gully region of northern Shaanxi Province in China. This study analyzed the effects of stand age on soil extracellular enzyme activities and soil microbial metabolic limitation. It also determined the main factor driving soil microbial metabolic limitation and extracellular enzyme activities. The results of ecoenzymatic stoichiometry showed that nitrogen (N) limited soil microbial metabolism in R. pseudoacacia plantations. Soil microbial metabolism at 10 and 22 years old were more carbon (C)‐ and N‐limited than that at 37 and 47 years old. Except for N‐ and phosphorus (P)‐acquiring enzyme activities at 10–20 cm, soil C‐, N‐, and P‐acquiring enzyme activities (in 0–10 and 10–20 cm of soil) at 10 and 22 years old were significantly higher than those at 37 and 47 years old. The enzymatic ratio of C:N:phosphorus(P) acquisition in all R. pseudoacacia plantations, regardless of stand age and soil depth, deviated from 1:1:1. Soil nutrients explained most of the variation (90.80%) in soil extracellular enzyme activities based on variation‐partitioning analysis. The partial least squares path model showed that soil nutrients had the highest total negative effect on microbial C limitation and microbial N/P limitation. Our results confirmed that microbial metabolic limitation was induced by soil resource deficits. The findings provide another visual that increases our understanding of soil microbial metabolic limitation in R. pseudoacacia plantations.
Isotope effects of O2 consumption in a deep lake as means for understanding partitioning of O2 demand among microorganisms, particles, and sediment
Authors: Musan Israela , Gildor Hezi , Gonsiorczyk Thomas , Grossart Hans‐Peter , Luz Boaz 
Published: February 2024

AbstractThe isotopic ratio 18O/16O of dissolved O2 in aquatic systems is affected by the preferential biological uptake of 16O (ε). Studies over the past six decades reveal that during incubation experiments, the isotopic effect of microorganism respiration (εorganism) varies in the range of −18‰ to −22‰. In contrast, natural variations in the deep‐ocean O2 concentration and δ18O levels show a considerably weaker effect (~ −10‰). The differences between these observations have been explained to result from either O2 uptake by sediments or organic particles that, due to diffusion‐limited respiration, are expected to weakly fractionate oxygen isotopes, by mixing processes or by weak fractionation at low temperatures. To gain better insight, we studied oxygen demand and δ18O in the deep, cold hypolimnion of Lake Stechlin between 2018 and 2021 as well as in various laboratory incubations. Our incubation results demonstrate an εorganism of about −24‰. Simple model calculations demonstrate a sediment O2 demand isotope effect (εSOD) of about −8.4‰, and a variated water‐column O2 demand isotope effect (εWOD) which is lower than εorganism, ranging from −13.9‰ in 2019 to −23‰ in 2021. Accompanying experiments indicate that the lower magnitude of εWOD may be related to respiration at organic particles lending to a weaker fractionation effect. Thus, variations in εWOD may reflect a changing partitioning of hypolimnion oxygen uptake between suspended particles and their containing microorganisms. Based on own incubation experiments with Daphnia carcasses, we discuss how possible changes of particle rigidity might influence εWOD.
The small nucleolar RNA SNORA51 enhances breast cancer stem cell‐like properties via the RPL3/NPM1/c‐MYC pathway
Authors: Li Shan , Jin Zining , Song Xinyue , Ma Jinfei , Peng Ziqi , Yu Hao , Song Jian , Zhang Yiqi , Sun Xiaoyu , He Miao , Yu Xinmiao , Jin Feng , Zheng Ang 
Published: February 2024

AbstractBreast cancer stem cells (BCSCs) are key players in carcinogenesis and development. Small nucleolar RNAs (snoRNAs) seem to have a crucial influence on regulating stem cell‐like properties in various cancers, but the underlying mechanism in breast cancer has not been determined. In this study, we first found that the expression of SNORA51 might be strongly and positively related to BCSCs‐like properties. SNORA51 expression was assessed in breast cancer tissues (n = 158 patients) by in situ hybridization. Colony formation, cell counting kit‐8, and sphere formation assays were used to detect cell proliferation and self‐renewal, respectively. Wound healing and transwell assays were used to detect cell migration. Coimmunoprecipitation and molecular docking were used to determine the underlying mechanism through which SNORA51 regulates BCSCs‐like properties. High SNORA51 expression was associated with a worse prognosis, overall survival, and disease‐free survival, in 158 breast cancer patients and was also closely related to lymph node status, ER status, the Ki‐67 index, histological grade, and TNM stage. Further analysis proved that SNORA51 could enhance and maintain stem cell‐like properties, including cell proliferation, self‐renewal, and migration, in breast cancer. Moreover, high SNORA51 expression could reduce nucleolar RPL3 expression, induce changes in the expression of NPM1 in the nucleolus and nucleoplasm, and ultimately increase c‐MYC expression. Taken together, our findings demonstrated that SNORA51 could enhance BCSCs‐like properties via the RPL3/NPM1/c‐MYC pathway both in vitro and in vivo. Therefore, SNORA51 might be a significant biomarker and potential therapeutic target and might even provide a new viewpoint on the regulatory mechanism of snoRNAs in breast cancer or other malignant tumors.
Emerging roles of nerve‐bone axis in modulating skeletal system
Authors: Li Jingya , Zhang Zhuoyuan , Tang Jinru , Hou Zeyu , Li Longjiang , Li Bo 
Published: February 2024

AbstractOver the past decades, emerging evidence in the literature has demonstrated that the innervation of bone is a crucial modulator for skeletal physiology and pathophysiology. The nerve‐bone axis sparked extensive preclinical and clinical investigations aimed at elucidating the contribution of nerve‐bone crosstalks to skeleton metabolism, homeostasis, and injury repair through the perspective of skeletal neurobiology. To date, peripheral nerves have been widely reported to mediate bone growth and development and fracture healing via the secretion of neurotransmitters, neuropeptides, axon guidance factors, and neurotrophins. Relevant studies have further identified several critical neural pathways that stimulate profound alterations in bone cell biology, revealing a complex interplay between the skeleton and nerve systems. In addition, inspired by nerve‐bone crosstalk, novel drug delivery systems and bioactive materials have been developed to emulate and facilitate the process of natural bone repair through neuromodulation, eventually boosting osteogenesis for ideal skeletal tissue regeneration. Overall, this work aims to review the novel research findings that contribute to deepening the current understanding of the nerve‐bone axis, bringing forth some schemas that can be translated into the clinical scenario to highlight the critical roles of neuromodulation in the skeletal system.
An improved gain and directivity design of an antipodal Vivaldi antenna for ultra‐wideband detection
Authors: Wang Jingjing , Li Yongcheng , Liu Jianwei , Fan Yucheng , Hou Kangming , Xu Huaqiang 
Published: February 2024

AbstractA novel antipodal Vivaldi antenna (AVA) is proposed to achieve improved gain and directivity. To enhance the bandwidth of the antenna, a series of equal‐sized slots are etched onto the patch surface. Additionally, a dielectric lens with a fan‐shaped structure is integrated along the patch openings to boost gain. The length of the lens which will affect the radiation characteristics of the antenna in the end‐fire direction will be discussed. Furthermore, three arrays of directors are added to enhance the directivity. The fabricated antenna is then measured using a vector network analyzer in a microwave chamber to assess its performance. The results indicate that the antenna's minimum operating frequency is reduced by 0.5 GHz after etching the slots. Besides, the average gain is improved by 1 dBi after installing the fan‐shaped expansion structure. By introducing the directors, the sidelobe levels decrease and the 3 dB Half‐Power Beamwidth becomes sharper. Finally, an ultra‐wideband (UWB) detection experiment is designed to analyze the detection capability of the fabricated antennas. The results demonstrate that the antenna is well‐suited for UWB applications.
Technical note: Workload and transmission data for mobile C‐arm fluoroscopy in gastrointestinal endoscopy
Authors: Li Xinhua , Marschall Theodore A. , Yang Kai , Liu Bob 
Published: February 2024

AbstractBackgroundMobile C‐arms may be used in fixed locations, and it is recommended that qualified experts evaluate structural shielding.PurposeTo assess clinical workload distributions for mobile C‐arms used in gastrointestinal endoscopy and determine the Archer equation parameters for the C‐arm beam spectra.MethodsConsecutive (30 months) gastrointestinal endoscopic procedures on two Cios Alpha systems (Siemens) were retrospectively analyzed. X‐ray tube voltage, tube current‐time product, reference point air kerma (Ka,r), air kerma‐area product (PKA), and fluoroscopic time were examined. The primary beam half‐value layer (HVL) was measured with an ionization chamber and aluminum 1100 plates. Stray radiation fraction at 1 m from a scattering source (ACR R/F phantom) was directly measured. Monte Carlo (Geant4) simulation was performed to calculate the transmission of broad X‐ray beams through lead, concrete, gypsum, and steel, with X‐ray HVLs matching those of the C‐arm X‐ray beam. The transmission data were fitted to the Archer equation.ResultsThe number of procedures (3509) was equivalent to 13.48 procedures per room per week. Dose quantities were 54.8 mGy (Ka,r), 18.3 Gy∙cm2 (PKA), and 7.8 min (fluoroscopic time) per procedure. X‐ray beam irradiation events were recorded for 2906 (82.8%) procedures with 160,009 events, whose mA‐minute weighted tube voltage was 91.0 kV and the workload was 0.68 mA‐minute per procedure. The two rooms had a significant difference in the number of procedures per week, 17.3 (29) [mean (maximum)] and 9.6 (16), respectively. The stray radiation fraction was 9.7×10−4 (80 kV) and 1.25×10−3 (120 kV). Transmission fitting parameters were provided for the tube voltage (on average, 90 kV; high end, 120 kV) of the C‐arm.ConclusionsThis work provides workload and transmission data for mobile C‐arm fluoroscopy in gastrointestinal endoscopy, which indicates a need for structural shielding evaluation of the procedure rooms.
Effects of different mass ratios on mechanical properties and impact energy release characteristics of Al/PTFE/W and Al/PTFE/CuO polymer composites
Authors: Xu Xiangchun , Fang Hongjie , Chen Rong , Yu Kun 
Published: February 2024

AbstractAluminum/polytetrafluoroethylene (Al/PTFE) is an impact‐initiated material that is extensively utilized in military and civilian applications due to its insensitivity, high energy density and ease of manufacturing. To increase both its compressive strength and energy density, Al/PTFE was doped with various amounts of W and CuO particles. These polymer composites exhibit elastoplastic properties, as well as significant strain hardening and strain‐rate hardening during compression deformation. At a strain rate of 5000 s−1, the compressive strength of the Al/PTFE/W and Al/PTFE/CuO specimens with an additive content of 30% reaches a peak of 194.1 and 189.2 MPa, which corresponds to an increase of 40.3% and 36.8%, respectively, compared with the compressive strength of Al/PTFE (138.3 MPa). The homogeneous bonding strength between the additives and PTFE and the fact that the elastic PTFE nanofibers inhibit the extension of microcracks are the main mechanical strengthening mechanisms. The reaction of the composites under high‐speed impact is violent and accompanied by sputtering sparks, and the reaction efficiency was determined using an improved drop‐hammer apparatus. As the W content increases, the impact reactivity of Al/PTFE/W decreases monotonically. However, as CuO content increases, the reaction intensity of Al/PTFE/CuO initially increases, and then decreases. At a CuO content of 30%, the energy release efficiency of Al/PTFE/CuO reaches its maximum (10.49%), which is 84.4% higher than that of Al/PTFE. TG‐DSC and XRD tests were performed to analyze the pyrolysis process and elucidate the reaction mechanism. A gas–solid chemical reaction model was developed, and the reactivity arises from multiple factors.Highlights
Typical elastoplastic characteristics as well as strain hardening and strain‐rate hardening were observed.
The mechanical strengthening effect of W particles is higher than that of CuO particles of Al/PTFE specimen.
The addition of W particles decreases the impact reactivity, but the addition of CuO particles improves the energy density of Al/PTFE.
The reaction efficiency of Al/PTFE/CuO reaches a peak of 10.49%, which increased by 84.4% compared with that of Al/PTFE.
Carbon fiber reinforced composites with self‐sensing and self‐healing capabilities enabled by CNT‐modified nanofibers
Authors: Wan Wenhu , Shen Rulin , Tang Juntao , Xu Yangbo , Zou Xiangfu , Guo Haibo 
Published: February 2024

AbstractCarbon fiber reinforced polymer (CFRP) composites with self‐sensing and self‐healing capabilities was developed in this work. Uniform dispersion of CNTs within a core‐shell nanofiber structure was achieved through a combination of electrospinning and subsequent surface spraying of CNTs. The resulting core‐shell nanofibers were incorporated into CFRP composites using a vacuum‐assisted resin transfer molding process. Mechanical testing demonstrated improved mechanical properties in the composites treated with CNT spraying. Real‐time, precise monitoring of structural damage was enabled through the measurement of electrical signal changes caused by composite deformation in static loading experiments. Furthermore, self‐healing experiments demonstrated that the thermally conductive network formed by CNTs facilitated more uniform heat transfer within the composites. During the healing process, resistive heating of damaged specimens was applied, resulting in a remarkable healing efficiency of 95.2%. The experiments indicate that the composite developed in this paper possess excellent self‐sensing and self‐healing capabilities.Highlights
Damage self‐sensing and self‐healing CFRP composites were developed.
CNTs‐modified nanofibers were applied to endow the composite specific abilities.
Resistivity signals were collected for real‐time damage monitoring.
The self‐healing efficiency of the designed composite reached up to 95.2%.
Self‐sensing and self‐healing occurred autonomously within closed‐loop structure.
Experimental investigation on the mechanical and acoustic performance of hemp/kenaf hybrid composites: Influence of different stacking sequences
Authors: Arshad Muhammad Nadeem , Thiagamani Senthil Muthu Kumar , Jeyaguru Sangilimuthukumar , Muthukumar Chandrasekar , Krishnasamy Senthilkumar , Subramaniam Jeyanthi , Khan Anish , Althomali Raed H. 
Published: February 2024

AbstractThis study investigated the effect of various stacking sequences on the mechanical and acoustic characteristics of hemp and kenaf fibers reinforced hybrid composites. The mechanical study was done by using universal testing machine and izod imact tester. Further, acoustic study was done by using impendence tube method. Hemp/kenaf/kenaf/hemp hybrid laminates outperformed the other composites in terms of tensile strength, flexural strength and impact strength. In the mono reinforcements, hemp/epoxy composites demonstrated superior mechanical characteristics than the epoxy matrix and kenaf/epoxy composites. However, hybrid composites have superior mechanical behavior compared to pure composites. From the acoustic results revealed that the pure hemp and kenaf/hemp/hemp/kenaf hybrid composites exhibitted highest sound transmission loss level at lowest and highest frequency region. The bestmechanical characteristics of hybrid composites will be suggested for use in automobile door panels. Also, the optimal sound transmission coefficent values signifying their appropriateness for use in applications that encompass many frequency bands.Highlights
Hybridization of kenaf/hemp fibers
Improved mechanical properties over the single fiber composites
Better acoustic properties
The curious case of the colored crystals of N‐substituted 2‐oxo‐1,2‐dihydropyridinyl‐3‐yl amines and amides: Self‐association in the solid state
Authors: Loughlin Wendy A. , Jenkins Ian D. , Healy Peter C. , Karis N. David , Pierens Gregory K. 
Published: February 2024

AbstractDuring a previous investigation of pyridone derivatives as inhibitors of glycogen phosphorylase, we observed that some N‐substituted 2‐oxo‐1,2‐dihydropyridinyl‐3‐yl amines and amides exhibited different colors, ranging from red to green to blue to teal. Remarkably, one compound (compound 8) could be crystallized in both a red form and a green form. To try to understand these observations, we have carried out further spectroscopic studies in the solid state and in solution employing UV‐visible spectroscopy, NMR spectroscopy, and X‐ray crystallography, along with molecular mechanics and DFT calculations on selected compounds. Evidence was obtained in the solid state for the self‐association of pyridones into dimeric complexes or near‐planar dimers induced by intermolecular hydrogen bonding and possible π‐stacking, whereas monomeric structures for two compounds were proposed in chloroform, in agreement with the DFT calculated chemical shifts. In this study, it was determined that the colors observed could not be attributed to hydrogen bonding or possible π‐bond stacking in the novel relatively unconjugated pyridone derivatives. A possible explanation for the colors is suggested: a contaminant formed by aerial oxidation of trace amounts of the 3‐aminopyridone starting material. This result contrasts with existing literature reports of UV and fluorescence spectra, which indicated distinct coloration for conjugated 2‐pyridone compounds. The spectroscopic results, including X‐ray structural data for five pyridones, contribute to a deeper understanding of structural interactions in pyridone derivatives.