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1.
Sci Total Environ ; 932: 173103, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38729358

RESUMO

Excessive synthetic nitrogen (N) inputs in intensive orchard agrosystems of developing countries are a growing concern regarding their adverse impacts on fruit production and the environment. Quantifying the distribution and contribution of fertilizer N is essential for increasing N use efficiency and minimizing N loss in orchards. A 15N tracer experiment was performed in a young dwarf apple orchard over two growing seasons to determine the fertilizer N transformation and fate. Fertilizer N primarily contributed to 25 % to 75 % of soil nitrate in the top 60 cm, but the contribution to soil microbial biomass N and fixed ammonium was <8 %, with the contribution to plant N ranging from 9 % to 19 %. In most growth periods, soil nitrate and fixed ammonium contents derived from native soil with N fertilization were higher than those not receiving N fertilizer. The N use efficiency of plants was only 2.6 % and 4.9 % in the first and second seasons, respectively, in contrast to 56.6 % and 54.0 % of N recovered in soil. Meanwhile, N assimilated into microbial biomass accounted for 0.8 %, and the proportion fixed by clay minerals was 3.5 %-5.2 %. One season after N fertilization, the nitrate below the 1 m soil layers accounted for 4.6 % of the applied N fertilizer, and the proportion increased to 22.5 % after two seasons. The N loss rate via N2O emission was 0.4 % over two years. The application of N fertilizer facilitated indigenous soil N mineralization, and abiotic ammonium fixation more efficiently retained synthetic N than microbial immobilization. These findings provide new insight into orchard N cycling, and attention should be given to the improvement of soil N retention and turnover capacity regulated by soil microbial and abiotic processes, as well as the potential environmental impacts of additional soil N mineralization resulting from prolonged chemical N fertilization.

2.
Sleep Breath ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38730204

RESUMO

STUDY OBJECTIVES: Artificial intelligence (AI) is quickly advancing in the field of sleep medicine, which bodes well for the potential of actual clinical use. In this study, an analysis of the 2nd China Intelligent Sleep Staging Competition was conducted to gain insights into the general level and constraints of AI-assisted sleep staging in China. METHODS: The outcomes of 10 teams from the children's track and 13 teams from the adult track were investigated in this study. The analysis included overall performance, differences between five different sleep stages, variations across subjects, and performance during stage transitions. RESULTS: The adult track's accuracy peaked at 80.46%, while the children's track's accuracy peaked at 88.96%. On average, accuracy rates stood at 71.43% for children and 68.40% for adults. All results were produced within a mere 5-min timeframe. The N1 stage was prone to misclassification as W, N2, and R stages. In the adult track, significant differences were apparent among subjects (p < 0.05), whereas in the children's track, such differences were not observed. Nonetheless, both tracks experienced a performance decline during stage transitions. CONCLUSIONS: The computational speed of AI is remarkably fast, simultaneously holding the potential to surpass the accuracy of physicians. Improving the machine learning model's classification of the N1 stage and transitional periods between stages, along with bolstering its robustness to individual subject variations, is imperative for maximizing its ability in assisting clinical scoring.

3.
J Exp Child Psychol ; 244: 105953, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38714153

RESUMO

This study investigated the role of dual- and single-language input in bilingual children's word learning. In Experiment 1, 26 Spanish-English bilingual children aged 4 and 5 years (9 girls; 73% Latino; 65% White) learned novel words in single- and dual-language conditions. In the single-language condition, children learned English-like labels for novel objects. In the dual-language condition, the same children learned Spanish- and English-like labels for a different set of objects; all labels were produced by the same bilingual speaker, creating competition between the two languages. A second group of bilingual children (N = 25; 14 girls; 72% Latino; 40% White) participated in Experiment 2, which tested whether tagging language by speaker in the dual-language condition (mimicking the one person-one language input strategy) would influence performance. In both experiments, participants learned novel English words above chance (ps < .05) in both conditions, with better performance in the single-language condition. These results indicate an advantage for single-language learning contexts, but the theoretical roots and the practical value of this advantage are unclear.

4.
Heliyon ; 10(9): e30341, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38707286

RESUMO

Emerging countries usually rely on the innovation of enterprises within the regional innovation ecosystem to enhance the national innovation level. However, existing literature lacks insight into how antitrust policies might influence innovation within them. We estimate the impact of the implementation of the Anti-Monopoly Law on enterprise innovation within Zhongguancun Science and Technology Park, China's prominentregional innovation ecosystem. Using a cross-industry difference-in-difference design, we show that greater exposure to competition shock materially boosted enterprise innovation. Antitrust policy promotes enterprise innovation by increasing the R&D investment, human capital, and export. The promotion effect of antitrust is relatively strong in the sample of electronic information industry, firms with low levels of financing constraints, and those that undertake open innovation. Our findings elucidate the nexus between competition and innovation in regional innovation ecosystems and underscore the pivotal role of antitrust policies in the development of Zhongguancun Science and Technology Park.

5.
Cancer Cell ; 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38729160

RESUMO

p53 was discovered 45 years ago as an SV40 large T antigen binding protein, coded by the most frequently mutated TP53 gene in human cancers. As a transcription factor, p53 is tightly regulated by a rich network of post-translational modifications to execute its diverse functions in tumor suppression. Although early studies established p53-mediated cell-cycle arrest, apoptosis, and senescence as the classic barriers in cancer development, a growing number of new functions of p53 have been discovered and the scope of p53-mediated anti-tumor activity is largely expanded. Here, we review the complexity of different layers of p53 regulation, and the recent advance of the p53 pathway in metabolism, ferroptosis, immunity, and others that contribute to tumor suppression. We also discuss the challenge regarding how to activate p53 function specifically effective in inhibiting tumor growth without harming normal homeostasis for cancer therapy.

6.
Harmful Algae ; 134: 102606, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38705611

RESUMO

Summer cyanobacterial blooms exhibit a dynamic interplay between toxic and non-toxic genotypes, significantly influencing the cyanotoxin levels within a lake. The challenge lies in accurately predicting these toxin concentrations due to the significant temporal fluctuations in the proportions of toxic and non-toxic genotypes. Typically, the toxic genotypes dominate during the early and late summer periods, while the non-toxic variants prevail in mid-summer. To dissect this phenomenon, we propose a model that accounts for the competitive interaction between toxic and non-toxic genotypes, as well as seasonal temperature variations. Our numerical simulations suggest that the optimal temperature of the toxic genotypes is lower than that of the optimal temperatures of the non-toxic counterparts. This difference of optimal temperature may potentially contribute to explain the dominance of toxic genotypes at the early and late summer periods, situation often observed in the field. Experimental data from the laboratory align qualitatively with our simulation results, enabling a better understanding of complex interplays between toxic and non-toxic cyanobacteria.


Assuntos
Cianobactérias , Estações do Ano , Temperatura , Cianobactérias/fisiologia , Proliferação Nociva de Algas , Lagos/microbiologia , Lagos/química , Modelos Biológicos
7.
Sci Rep ; 14(1): 10447, 2024 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-38714726

RESUMO

Polyandry, the practice of females mating with multiple males, is a strategy found in many insect groups. Whether it increases the likelihood of receiving beneficial genes from male partners and other potential benefits for females is controversial. Strepsiptera are generally considered monandrous, but in a few species females have been observed copulating serially with multiple males. Here we show that the offspring of a single female can have multiple fathers in two Strepsiptera species: Stylops ovinae (Stylopidae) and Xenos vesparum (Xenidae). We studied female polyandry in natural populations of these two species by analysis of polymorphic microsatellite loci. Our results showed that several fathers can be involved in both species, in some cases up to four. Mating experiments with S. ovinae have shown that the first male to mates with a given female contributes to a higher percentage of the offspring than subsequent males. In X. vesparum, however, we found no significant correlation between mating duration and offspring contribution. The prolonged copulation observed in S. ovinae may have the advantage of reducing competition with sperm from other males. Our results show that monandry may not be the general pattern of reproduction in the insect order Strepsiptera.


Assuntos
Insetos , Repetições de Microssatélites , Comportamento Sexual Animal , Espermatozoides , Animais , Masculino , Feminino , Comportamento Sexual Animal/fisiologia , Espermatozoides/fisiologia , Insetos/fisiologia , Repetições de Microssatélites/genética , Reprodução/fisiologia
8.
Ecol Evol ; 14(5): e11425, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38746546

RESUMO

Understanding the relationship between plant diversity and invasibility is essential in invasion ecology. Species-rich communities are hypothesized to be more resistant to invasions than species-poor communities. However, while soil microorganisms play a crucial role in regulating this diversity-invasibility relationship, the effects of plant competition mode and soil nutrient status on their role remain unclear. To address this, we conducted a two-stage greenhouse experiment. Soils were first conditioned by growing nine native species separately in them for 1 year, then mixed in various configurations with soils conditioned using one, three, or six species, respectively. Next, we inoculated the mixed soil into sterilized substrate soil and planted the alien species Rhus typhina and native species Ailanthus altissima as test plants. We set up two competition modes (intraspecific and interspecific) and two nutrient levels (fertilization using slow-release fertilizer and nonfertilization). Under intraspecific competition, regardless of fertilization, the biomass of the alien species was higher in soil conditioned by six native species. By contrast, under interspecific competition, the biomass increased without fertilization but remained stable with fertilization in soil conditioned by six native species. Analysis of soil microbes suggests that pathogens and symbiotic fungi in diverse plant communities influenced R. typhina growth, which varied with competition mode and nutrient status. Our findings suggest that the soil microbiome is pivotal in mediating the diversity-invasibility relationship, and this influence varies according to competition mode and nutrient status.

9.
Sci Total Environ ; : 172956, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38719036

RESUMO

Paddy soil, as an ecosystem with alternating drained and flooded conditions, microorganisms in it can maintain the stability of the ecosystem by regulating the composition and diversity of its species when disturbed by external biotic or abiotic factors, and the regulatory mechanism in this process is a controversial topic in ecological research. In this study, we investigate the effects of pigeon feces addition on bacterial communities in three textured soils, two conditions (drained and flooded) based on microcosm experiment using high-throughput sequencing techniques. Our results show that pigeon feces addition reduced environmental heterogeneity and community diversity, both under flooded and drained conditions and in all textured soils, thereby decreasing the effectiveness of environmental selection and increasing diffusion limitations among bacterial communities. Bacterial communities are altered by environmental factors including total organic carbon, available nitrogen, total phosphorus, available phosphorus and available potassium, resulting in the formation of new community structures and dominant genera. Bacteria from pigeon feces did not colonize the original soil in large numbers, and the soil bacterial community structure changed, with some species replaced the indigenous ones as new dominant genera. As nutrient diffusion increases the nutrient content of the soil, this does not lead to species extinction; however, nutrient diffusion creates new nutrient preferences of the bacterial community, which causes direct competition between species, and contributes to the extinction and immigration species. Our results suggest that species replacement is an adaptive strategy of soil bacterial community in response to dispersal of pigeon feces, and that bacterial community regulate diversity and abundance of the community by enhancing species extinction and immigration, thereby preventing bacteria in pigeon feces from colonizing paddy soils and maintaining ecosystem stability.

10.
Data Brief ; 54: 110443, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38708298

RESUMO

In recent years, both in the world of research and consulting, the concept of innovation in the business model has been gaining a lot of interest. As a result, an incipient number of scientific and popular publications are being generated, which try to delimit and explain this term, as well as work methodologies for its application in the business world. The family business field can benefit from the application of this approach. But, at the same time, it can also serve as an object of study since its special idiosyncrasy will allow to deepen the analysis of successful business models. To illustrate innovation in business models, data from 112 family firms representative of the regional economy are presented. The companies are also associated with the Murcian Association of Family Businesses (Amefmur). The collaboration with this organization has made it possible to obtain very valuable and representative information thanks to the support provided. The collection of information was carried out through an electronic survey. These data could be especially useful for establishing business recommendations for this type of companies and for analyzing other possible interrelationships of the variables available in the database.

11.
Front Plant Sci ; 15: 1342512, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38708395

RESUMO

Carrot (Daucus carota L.) is a high value, nutritious, and colorful crop, but delivering carrots from seed to table can be a struggle for carrot growers. Weed competitive ability is a critical trait for crop success that carrot and its apiaceous relatives often lack owing to their characteristic slow shoot growth and erratic seedling emergence, even among genetically uniform lines. This study is the first field-based, multi-year experiment to evaluate shoot-growth trait variation over a 100-day growing season in a carrot diversity panel (N=695) that includes genetically diverse carrot accessions from the United States Department of Agriculture National Plant Germplasm System. We report phenotypic variability for shoot-growth characteristics, the first broad-sense heritability estimates for seedling emergence (0.68 < H2 < 0.80) and early-season canopy coverage ( 0.61 < H2 < 0.65), and consistent broad-sense heritability for late-season canopy height (0.76 < H2 < 0.82), indicating quantitative inheritance and potential for improvement through plant breeding. Strong correlation between emergence and canopy coverage (0.62 < r < 0.72) suggests that improvement of seedling emergence has great potential to increase yield and weed competitive ability. Accessions with high emergence and vigorous canopy growth are of immediate use to breeders targeting stand establishment, weed-tolerance, or weed-suppressant carrots, which is of particular advantage to the organic carrot production sector, reducing the costs and labor associated with herbicide application and weeding. We developed a standardized vocabulary and protocol to describe shoot-growth and facilitate collaboration and communication across carrot research groups. Our study facilitates identification and utilization of carrot genetic resources, conservation of agrobiodiversity, and development of breeding stocks for weed-competitive ability, with the long-term goal of delivering improved carrot cultivars to breeders, growers, and consumers. Accession selection can be further optimized for efficient breeding by combining shoot growth data with phenological data in this study's companion paper to identify ideotypes based on global market needs.

12.
J Child Lang ; : 1-34, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38712583

RESUMO

We assess the feasibility of conducting web-based eye-tracking experiments with children using two methods of webcam-based eye-tracking: automatic gaze estimation with the WebGazer.js algorithm and hand annotation of gaze direction from recorded webcam videos. Experiment 1 directly compares the two methods in a visual-world language task with five to six year-old children. Experiment 2 more precisely investigates WebGazer.js' spatiotemporal resolution with four to twelve year-old children in a visual-fixation task. We find that it is possible to conduct web-based eye-tracking experiments with children in both supervised (Experiment 1) and unsupervised (Experiment 2) settings - however, the webcam eye-tracking methods differ in their sensitivity and accuracy. Webcam video annotation is well-suited to detecting fine-grained looking effects relevant to child language researchers. In contrast, WebGazer.js gaze estimates appear noisier and less temporally precise. We discuss the advantages and disadvantages of each method and provide recommendations for researchers conducting child eye-tracking studies online.

13.
Ann Bot ; 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38712800

RESUMO

The deceptive strategies by which orchids are pollinated and how these are capable of attracting pollinators remain understudied with regard to their implications on plant fitness. Despite its ecological importance, limited investigations have been conducted on sexual deception and shelter mimicry in orchid species, making it a compelling avenue in orchid biology research. To expand the knowledge of these reproductive mechanisms, we studied the pollination of Serapias lingua and S. parviflora, in co-occurring and isolated sites in Balearic Islands (Spain), further accentuated by the presence of a hybrid, indicating shared pollinators. We employed bagging and hand pollination experiments to examine their reproductive biology. Furthermore, we evaluated the influence of phenotypical and ecological factors on reproductive success, including biometric measurements, reproductive performance and neighborhood diversity (co-flowering and pollinator communities). Reproductive mechanisms between these two orchid species exhibit substantial disparities. Serapias lingua relies primarily on insect-mediated pollination, while S. parviflora demonstrates self-reproduction capacity. Although events of open pollination are rare, hybridization occurs predominantly when S. lingua is the pollen donor. Fruit set in S. parviflora was positively correlated with plant height, while in S. lingua it was negatively associated with flower size. The coexistence of both species positively affected pollinia removal in S. parviflora, but did not exert an influence on reproductive traits in S. lingua. Overall, biometric parameters were diminished in isolated compared to co-occurring sites. At the community level, the increased diversity of co-flowering species in the vicinity exhibited an inhibitory effect on pollinia removal in S. parviflora. Under a context of pollinator loss or phenological mismatch between pollinator presence and flowering, the selfing capacity of S. parviflora would guarantee reproduction whereas S. lingua survival would be compromised. Furthers studies are needed to assess the effects of phenotypical and ecological factors on reproductive success of S. lingua in pollinator-decline scenarios.

14.
Microbiol Spectr ; : e0427823, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38712967

RESUMO

Within the realm of Gram-negative bacteria, bacteriocins are secreted almost everywhere, and the most representative are colicin and pyocin, which are secreted by Escherichia coli and Pseudomonas aeruginosa, respectively. Signal peptides at the amino terminus of bacteriocins or ABC transporters can secrete bacteriocins, which then enter bacteria through cell membrane receptors and exert toxicity. In general, the bactericidal spectrum is usually narrow, killing only the kin or closely related species. Our previous research indicates that YPK_0952 is an effector of the third Type VI secretion system (T6SS-3) in Yersinia pseudotuberculosis. Next, we sought to determine its identity and characterize its toxicity. We found that YPK_0952 (a pyocin-like effector) can achieve intra-species and inter-species competitive advantages through both contact-dependent and contact-independent mechanisms mediated by the T6SS-3 while enhancing the intestinal colonization capacity of Y. pseudotuberculosis. We further identified YPK_0952 as a DNase dependent on Mg2+, Ni2+, Mn2+, and Co2+ bivalent metal ions, and the homologous immune protein YPK_0953 can inhibit its activity. In summary, YPK_0952 exerts toxicity by degrading nucleic acids from competing cells, and YPK_0953 prevents self-attack in Y. pseudotuberculosis.IMPORTANCEBacteriocins secreted by Gram-negative bacteria generally enter cells through specific interactions on the cell surface, resulting in a narrow bactericidal spectrum. First, we identified a new pyocin-like effector protein, YPK_0952, in the third Type VI secretion system (T6SS-3) of Yersinia pseudotuberculosis. YPK_0952 is secreted by T6SS-3 and can exert DNase activity through contact-dependent and contact-independent entry into nearby cells of the same and other species (e.g., Escherichia coli) to help Y. pseudotuberculosis to exert a competitive advantage and promote intestinal colonization. This discovery lays the foundation for an in-depth study of the different effector protein types within the T6SS and their complexity in competing interactions. At the same time, this study provides a new development for the toolbox of toxin/immune pairs for studying Gram-negative bacteriocin translocation.

15.
Oecologia ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38727828

RESUMO

Light competition is thought to drive successional shifts in species dominance in closed vegetations, but few studies have assessed this for species-rich and vertically structured tropical forests. We analyzed how light competition drives species replacement during succession, and how cross-species variation in light competition strategies is determined by underlying species traits. To do so, we used chronosequence approach in which we compared 14 Mexican tropical secondary rainforest stands that differ in age (8-32 year-old). For each tree, height and stem diameter were monitored for 2 years to calculate relative biomass growth rate (RGR, the aboveground biomass gain per unit aboveground tree biomass per year). For each stand, 3D light profiles were measured to estimate individuals' light interception to calculate light interception efficiency (LIE, intercepted light per unit biomass per year) and light use efficiency (LUE, biomass growth per intercepted light). Throughout succession, species with higher RGR attained higher changes in species dominance and thus increased their dominance over time. Both light competition strategies (LIE and LUE) increased RGR. In early succession, a high LIE and its associated traits (large crown leaf mass and low wood density) are more important for RGR. During succession, forest structure builds up, leading to lower understory light levels. In later succession, a high LUE and its associated traits (high wood density and leaf mass per area) become more important for RGR. Therefore, successional changes in relative importance of light competition strategies drive shifts in species dominance during tropical rainforest succession.

16.
Int Immunol ; 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38708774

RESUMO

Persistent immunoglobulin G (IgG) production (PIP) provides long-term vaccine protection. While variations in the duration of protection have been observed with vaccines prepared from different pathogens, little is known about the factors that determine PIP. Here, we investigated the impact of three parameters on the duration of anti-peptide IgGs production, namely amino acid sequences, protein carriers, and immunization programs. We show that anti-peptide IgGs production can be transformed from transient IgG production (TIP) to PIP, by placing short peptides (Pi) containing linear B cell epitopes in different competitive environments using bovine serum albumin (BSA) conjugates instead of the original viral particles. When goats were immunized with the peste des petits ruminants (PPR) live-attenuated vaccine (containing Pi as the constitutive component) and BSA-Pi conjugate, anti-Pi IgGs production exhibited TIP (duration <60 days) and PIP (duration >368 days), respectively. Further, this PIP was unaffected by subsequent immunization with the PPR live-attenuated vaccine in the same goat. When goats were co-immunized with PPR live-attenuated vaccine and BSA-Pi, the induced anti-Pi IgGs production showed a slightly extended TIP (from ~60 days to ~100 days). This discovery provides new perspectives for studying the fate of plasma cells in humoral immune responses and developing peptide vaccines related to linear neutralizing epitopes from various viruses.

17.
J Bacteriol ; : e0027323, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38717111

RESUMO

Type VI secretion system (T6SS) is a potent weapon employed by various Pseudomonas species to compete with neighboring microorganisms for limited nutrients and ecological niches. However, the involvement of T6SS effectors in interbacterial competition within the phytopathogen Pseudomonas syringae remains unknown. In this study, we examined two T6SS clusters in a wild-type P. syringae MB03 and verified the involvement of one cluster, namely, T6SS-1, in interbacterial competition. Additionally, our results showed that two T6SS DNase effectors, specifically Tde1 and Tde4, effectively outcompeted antagonistic bacteria, with Tde4 playing a prominent role. Furthermore, we found several cognate immunity proteins, including Tde1ia, Tde1ib, and Tde4i, which are located in the downstream loci of their corresponding effector protein genes and worked synergistically to protect MB03 cells from self-intoxication. Moreover, expression of either Tde1 or C-terminus of Tde4 in Escherichia coli cells induced DNA degradation and changes in cell morphology. Thus, our results provide new insights into the role of the T6SS effectors of P. syringae in the interbacterial competition in the natural environment. IMPORTANCE: The phytopathogen Pseudomonas syringae employs an active type VI secretion system (T6SS) to outcompete other microorganisms in the natural environment, particularly during the epiphytic growth in the phyllosphere. By examining two T6SS clusters in P. syringae MB03, T6SS-1 is found to be effective in killing Escherichia coli cells. We highlight the excellent antibacterial effect of two T6SS DNase effectors, namely, Tde1 and Tde4. Both of them function as nuclease effectors, leading to DNA degradation and cell filamentation in prey cells, ultimately resulting in cell death. Our findings deepen our understanding of the T6SS effector repertoires used in P. syringae and will facilitate the development of effective antibacterial strategies.

18.
Ecol Evol ; 14(5): e11338, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38698926

RESUMO

Gamete traits can vary widely among species, populations and individuals, influencing fertilisation dynamics and overall reproductive fitness. Sexual selection can play an important role in determining the evolution of gamete traits with local environmental conditions determining the strength and direction of sexual selection. Here, we test for signatures of post-mating selection on gamete traits in relation to population density, and possible interactive effects of population density and sperm concentration on sperm motility and fertilisation rates among natural populations of mussels. Our study shows that males from high-density populations produce smaller sperm compared with males from low-density populations, but we detected no effect of population density on egg size. Our results also reveal that females from low-density populations tended to exhibit lower fertilisation rates across a range of sperm concentrations, although this became less important as sperm concentration increased. Variances in fertilisation success were higher for females than males and the effect of gamete compatibility between males and females increases as sperm concentrations increase. These results suggest that local population density can influence gamete traits and fertilisation dynamics but also highlight the importance of phenotypic plasticity in governing sperm-egg interactions in a highly dynamic selective environment.

19.
Heliyon ; 10(8): e29511, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38699729

RESUMO

In the context of sustainable development, market competition is intensifying, and financial constraints have emerged as a significant hindrance to green project investment. Green Supply Chain Finance (GSCF), characterized by long-term collaboration, has emerged as a crucial financial approach to mitigate corporate financial limitations and channel capital flows into environmentally friendly industries. We propose a two-echelon supply chain with one supplier and two competing retailers over a single period and investigate ordering, sales, and financing decisions simultaneously under competition. Retailers constrained by financial considerations may secure GSCF or traditional bank financing (BF) loans. This study investigates the influence of competition on pricing and sales strategies during the selling season. The results demonstrate that retailers select between clearance and responsive selling strategies based on the level of market competition. During the ordering season, retailers share the product market equally when interest rates are uniform, and the supplier formulates a supply chain contract while considering the financing interest rate. In the presence of differential interest rates, retailers may not always opt for the GSCF, even when they offer an interest rate advantage, due to the comprehensive impacts of operational and financial strategies. Remarkably, competitive retailers do not choose the GSCF when their initial green investment capital surpasses a certain threshold.

20.
Ecol Evol ; 14(5): e11373, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38711489

RESUMO

Megaherbivore carcasses represent sporadic but energetically rewarding resources for carnivores, offering a unique opportunity to study coexistence dynamics between facultative scavengers. South African fenced protected areas, such as Madikwe Game Reserve (Madikwe hereafter), host viable populations of large carnivores and high densities of elephants, Loxodonta africana. However, high carnivore densities can lead to potentially fatal interspecific encounters and increased competition, particularly around high-quality trophic resources. This study explores the temporal partitioning and co-detection strategies of carnivores at six elephant carcasses in Madikwe, aiming to understand how the increased carrion biomass available at elephant carcasses influences coexistence dynamics. Camera traps were deployed to monitor carcasses during two periods (2019 and 2020), revealing occurrences of six carnivore species. Carnivores, particularly black-backed jackals, Lupulella mesomelas, (hereafter jackal), lions, Panthera leo, and spotted hyaenas, Crocuta crocuta, comprised 56.7% of carcass observations, highlighting their pivotal roles in scavenging dynamics. Pairwise co-detection analysis demonstrated consistent association and shared peak activity periods between jackals and spotted hyaenas, indicating potential resource sharing. However, the minimal co-detection rates between lions and other carnivores highlight their resource domination. There was some evidence of temporal partitioning between carnivores, with most species exhibiting earlier peaks in nocturnal activity to avoid temporal overlap with lions. This study emphasises the importance of elephant carcasses in the diet of multiple species and coexistence techniques utilised to exploit this ephemeral resource. As fenced protected areas become crucial for conserving intact carnivore guilds globally, further research into carnivore behavioural adaptations at carcasses is recommended to shed light on their coexistence strategies.

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