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EcologicalNetworksDynamics.jl: a Julia package to simulate the temporal dynamics of complex ecological networks
Get PDFSpecies interactions play a crucial role in shaping biodiversity, species coexistence, population dynamics, community stability and ecosystem functioning. Our understanding of the role of the diversity of species interactions driving these species, community and ecosystem features is limited because current approaches often focus only on trophic interactions. This is why a new modelling framework that includes a greater diversity of interactions between species is crucially needed.
We developed a modular, user-friendly, and extensible Julia package that delivers the core functionality of the bio-energetic food web model. Moreover, it embeds several ecological interaction types alongside the capacity to manipulate external drivers of ecological dynamics. These new features represent important processes known to influence biodiversity, coexistence, functioning and stability in natural communities. Specifically, they include: (a) an explicit multiple nutrient intake model for producers, (b) competition among producers, (c) temperature dependence implemented via the Boltzmann-Arhennius rule, and (d) the ability to model several non-trophic interactions including competition for space, plant facilitation, predator interference and refuge provisioning.
The inclusion of the various features provides users with the ability to ask questions about multiple simultaneous processes and stressor impacts, and thus develop theory relevant to real world scenarios facing complex ecological communities in the Anthropocene. It will allow researchers to quantify the relative importance of different mechanisms to stability and functioning of complex communities.
The package was build for theoreticians seeking to explore the effects of different types of species interactions on the dynamics of complex ecological communities, but also for empiricists seeking to confront their empirical findings with theoretical expectations. The package provides a straightforward framework to model explicitly complex ecological communities or provide tools to generate those communities from few parameters
Neutrino cosmology after DESI: tightest mass upper limits, preference for the normal ordering, and tension with terrestrial observations
Get PDFThe recent DESI Baryon Acoustic Oscillation measurements have led to tight upper limits on the neutrino mass sum, potentially in tension with oscillation constraints requiring ∑ mν ≳ 0.06 eV. Under the physically motivated assumption of positive ∑ mν, we study the extent to which these limits are tightened by adding other available cosmological probes, and robustly quantify the preference for the normal mass ordering over the inverted one, as well as the tension between cosmological and terrestrial data. Combining DESI data with Cosmic Microwave Background measurements and several late-time background probes, the tightest 2σ limit we find without including a local H0 prior is ∑ mν < 0.05 eV. This leads to a strong preference for the normal ordering, with Bayes factor relative to the inverted one of 46.5. Depending on the dataset combination and tension metric adopted, we quantify the tension between cosmological and terrestrial observations as ranging between 2.5σ and 5σ. These results are strenghtened when allowing for a time-varying dark energy component with equation of state lying in the physically motivated non-phantom regime, w(z) ≥ -1, highlighting an interesting synergy between the nature of dark energy and laboratory probes of the mass ordering. If these tensions persist and cannot be attributed to systematics, either or both standard neutrino (particle) physics or the underlying cosmological model will have to be questioned
Highly Efficient and Stable CsPbI3 Perovskite Quantum Dots Light-Emitting Diodes Through Synergistic Effect of Halide-Rich Modulation and Lattice Repair
No full textCurrently, CsPbI3 quantum dots (QDs) based light-emitting diodes (LEDs) are not well suited for achieving high efficiency and operational stability due to the binary-precursor method and purification process, which often results in the nonstoichiometric ratio of Cs/Pb/I. This imbalance leads to amounts of iodine vacancies, inducing severe non-radiative recombination processes and phase transitions of QDs. Herein, red-emitting CsPbI3 QDs are reported with excellent optoelectronic properties and stability based on the synergistic effects of halide-rich modulation passivation and lattice repair. First, a ternary-precursor method is employed to better control the feed ratio of Cs/Pb/I and create a halide-rich environment. Second a solvent-free solid–liquid reaction employing a multifunctional guanidinium iodide (GAI) additive is used after purification to repair iodine vacancies and partially replace surface Cs atoms, thereby effectively modifying its tolerance factor. Additionally, this short-chain GA+ can be used as the surface ligand to improve the conductivity of the QDs and suppress trap-assisted non-radiative Auger recombination. Consequently, PeLEDs based on GAI-QDs exhibit a great maximum external quantum efficiency (EQE) of 27.1% and an operational half-lifetime (T50) of 1001.1 min at an initial luminance of 100 cd m−2
SERS aptasensor detection of aflatoxin B1 based on silicon-au-ag Janus nanocomposites
Get PDFAflatoxin B1 (AFB1) is a prevalent contaminant in maize, posing significant threats to human health. This study designed Au[sbnd]Ag Janus NPs with intrinsic Raman signals as signal probes and SiO2@AgNPs as capture probes. The two were coupled through complementary base pairing to ensure the ordered, controlled distribution of noble metal nanoparticles. The Au[sbnd]Ag Janus NPs and the highly stable SiO2 carrier is expected to avoid the adverse effects on stability caused by using signal molecules and the formation of random aggregates when using the noble metal nanoparticle gap effect to concentrate on the electromagnetic field. This study improved the negative impact of AgNPs' high surface energy on their uniformity, while enhancing the pH adaptability of Au[sbnd]Ag Janus NPs. In the presence of AFB1, the composite disintegrates, and the SERS intensity showed a negative correlation with AFB1 concentration, enabling highly sensitive and stable detection of AFB1
Exploring the experiences of cognitive symptoms in Long COVID: a mixed-methods study in the UK.
Get PDFObjective
To explore the lived experiences and extent of cognitive symptoms in Long COVID (LC) in a UK-based sample.
Design
This study implemented a mixed-methods design. Eight focus groups were conducted to collect qualitative data, and the Framework Analysis was used to reveal the experiences and impact of cognitive symptoms. A self-report questionnaire was used to collect the quantitative data to assess the perceived change and extent of symptomology post COVID-19.
Setting
Focus groups were conducted in April 2023 online via Zoom and in-person at the University of Leeds, UK.
Participants 25 people with LC living in the UK participated in the study. Participants were aged 19–76 years (M=43.6 years, SD=14.7) and included 17 women and 8 men.
Results
Reduced cognitive ability was among the most prevalent symptoms reported by the study participants. Three key themes were identified from the qualitative data: (1) rich accounts of cognitive symptoms; (2) the impact on physical function and psychological well-being and (3) symptom management. Descriptions of cognitive symptoms included impairments in memory, attention, language, executive function and processing speed. Cognitive symptoms had a profound impact on physical functioning and psychological well-being, including reduced ability to work and complete activities of daily living. Strategies used for symptom management varied in effectiveness.
Conclusion
Cognitive dysfunction in LC appears to be exacerbated by vicious cycle of withdrawal from daily life including loss of employment, physical inactivity and social isolation driving low mood, anxiety and poor cognitive functioning. Previous evidence has revealed the anatomical and physiological biomarkers in the brain affecting cognition in LC. To synthesise these contributing factors, we propose the Long-COVID Interacting Network of factors affecting Cognitive Symptoms. This framework is designed to inform clinicians and researchers to take a comprehensive approach towards LC rehabilitation, targeting the neural, individual and lifestyle factors
The Value of Whole-Face Procedures for the Construction and Naming of Identifiable Likenesses for Recall-Based Methods of Facial-Composite Construction
Get PDFTraditional methods of facial-composite construction rely on an eyewitness recalling features of an offender's face. We assess the value of the addition of a trait–recall mnemonic to a cognitive-type interview, and perceptually stretching presented composites, to aid image recognition. Participant-constructors intentionally or incidentally encoded a target face, were interviewed about its facial features 3–4 h or 2 days later, made a series of trait attributions (or not) about the face and constructed a feature-based composite. Regardless of encoding manipulation, faces constructed after 3–4 h were twice as likely to be correctly named (cf. after 2 days) both when the trait–recall mnemonic was applied and composites were viewed stretched. Thus, the research indicates that benefit should be afforded when trait–recall mnemonics are employed for feature composites constructed on the same day as the crime and when composites are presented to potential recognisers with instruction to view the face as a perceptual stretch
Identifying the Public's Beliefs about Generative Artificial Intelligence: A Big Data Approach
Get PDFIn an era where generative AI (GenAI) is reshaping industries, public understanding of this phenomenon remains limited. This study addresses this gap by analysing public beliefs about GenAI using the Technology Acceptance Model (TAM) and Diffusion of Innovations Theory (DOI) as frameworks. We adopted a big-data approach, utilising machine-learning techniques to analyse 21,817 public comments extracted from an initial set of 32,707 on 44 YouTube videos discussing GenAI. Our investigation surfaced six pivotal themes: concerns over job and economic impacts, GenAI's potential to revolutionise problem-solving, its perceived shortcomings in creativity and emotional intelligence, the proliferation of misinformation, existential risks, and privacy decay. Emotion analysis showed that negative emotions dominated at 58.46%, including anger (22.85%) and disgust (17.26%). Sentiment analysis echoed this negativity, with 70% negative. The triangulation of thematic, emotional, and sentiment analyses highlighted a polarised public stance: recognition of GenAI's transformative potential is tempered by significant concerns about its implications. The findings offer actionable insights for engineering managers and policymakers. Strategies such as awareness-building, transparency, public engagement, balanced communication, governance, and human-centred development can address polarisation and build trust. Ongoing research into public opinion remains essential for aligning technological advancements with societal expectations and acceptance
Urban vertical farming:innovation for food security and social impact?
Get PDFUrban vertical farming (VF) has emerged as a potential solution to improve food security and safety for urban populations, as well as to transform wider food systems (FS) to ensure greater sustainability. Existing literature has highlighted both direct and indirect benefits from VF to individuals and communities through novel technology alongside social entrepreneurial innovation. These include the creation of green jobs, and greater access to fresh, healthy food produced locally, as well as community development programmes and avenues for civic participation. We explore relevant literature to critically examine the socio-economic impact of VF, drawing out key issues of debate, while identifying areas of future research and recommendations for practice. We draw attention to critical accounts that have highlighted a need to consider the role of technology within social and political processes. Studies have noted key challenges to VF in achieving social and economic benefits to urban populations, as well as in contributing to food security. Examining VF as an intervention within a wider political economy enables a more rigorous exploration of social impact. A research, policy and practice focus beyond production and business model design is needed to situate VF within broader efforts to transform FS . This article is part of the theme issue ‘Transforming terrestrial food systems for human and planetary health
A new method for concomitant evaluation of drug combinations for their antimicrobial properties
Get PDFMicrobial pathogens have developed resistance mechanisms to almost every antibiotic available. There is a need to synthesize or screen new natural compounds to combat the development of drug-resistant pathogens. One of the commonly used methods to evaluate the antimicrobial activity of two or more antibiotics involves a checkerboard assay, which is cumbersome, time-consuming, and expensive. We have developed a quick, reliable, and cost-effective method to evaluate the antimicrobial effect of two or more antibiotics at fixed doses with different concentrations of a novel natural ingredient or test compound.
The technique involves the following steps:
• Preparation of a bacterial culture of the test strain at 0.5 McFarland standard (0.1 OD at 600 nm), and preparation of stock solutions for the chemical of interest and standard drugs.
• The required amount of all three components can be dispensed into respective wells of a microplate using multichannel pipette.
• Optical density (OD) values obtained would be directly related to the individual as well as combined effect of compounds on the given bacterial strain
An Operationally Unsaturated Iridium-Pincer Complex That C-H Activates Methane and Ethane in the Crystalline Solid-State
Get PDFThe known complex [Ir( t Bu-PONOP)MeH][BAr F 4], 1[BAr F 4 ] [ t Bu-PONOP = κ 3-2,6-( t Bu 2PO) 2C 5H 3N); Ar F = 3,5-(CF 3) 2(C 6H 3); J. Am. Chem. Soc. 2009, 131, 8603], is a robust precursor for in crystallo single-crystal to single-crystal (SC-SC) C-H activation of methane and ethane at 80 °C. This contrasts with the reported solution (CD 2Cl 2) behavior, where 1[BAr F 4 ] decomposes by methane loss. Crystalline 1[BAr F 4 ] is accessed as a single polymorph on a gram scale. A single-crystal neutron diffraction study locates the hydride. 13C{ 1H} SSNMR experiments on 1[BAr F 4 ], and its isotopologue [Ir( t Bu-PONOP)(CD 3)D][BAr F 4], d 4 -1[BAr F 4 ], suggest a rapid and reversible endergonic reductive bond formation is occurring in crystallo to access an Ir(I) σ-methane complex. Heating 1[BAr F 4 ] to 80 °C under high vacuum results in loss of methane and intramolecular C-H activation to form cyclometalated [Ir(cyclo- t Bu-PONOP')H][BAr F 4], 2[BAr F 4 ], in a SC-SC reaction. This is reversible, and the addition of CH 4 or CD 4 to 2[BAr F 4 ] at 80 °C results in an equilibrium with 1[BAr F 4 ] or d 4 -1[BAr F 4 ], respectively. Complex 2[BAr F 4 ] is thus an operationally unsaturated source of 14-electron [Ir( tBu-PONOP)][BAr F 4], III, that undergoes C-H activation with methane. Periodic DFT studies, alongside isotope labeling experiments, link 1[BAr F 4 ] and 2[BAr F 4 ]/CH 4 via a reductive elimination/oxidative addition pathway. Heating 2[BAr F 4 ] to 80 °C under N 2 forms [Ir( t Bu-PONOP)(κ 1-N 2)][BAr F 4], in a SC-SC transformation. Reaction with CO forms [Ir( t Bu-PONOP)(CO)][BAr F 4] at room temperature. Calculations suggest reaction with N 2 occurs via an associative process or competitively through III, while with CO only an associative process operates. Heating 2[BAr F 4 ] to 80 °C under an ethane atmosphere results in alkane dehydrogenation, via a SC-SC reaction, forming a ∼1:1 mixture of [Ir( t Bu-PONOP)(η 2-H 2C═CH 2)][BAr F 4], and [Ir( t Bu-PONOP)H 2][BAr F 4]
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