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Fungal succession, litter decomposition and root nitrogen supply in a tropical oil palm plantation
Get PDFBackground and Aims Industrial oil palm plantation
management degrades tropical soils and disrupts
ecosystem functions. Applying oil palm leaf litter can
help restore soil fertility, but the underlying fungaldriven
decomposition and nitrogen recycling remain
understudied. This study examines fungal succession
in degrading oil palm leaf litter, the fate of litterderived
nitrogen in soil and roots, and the potential
for the restoration of fungal biodiversity.
Methods We produced 15N-labelled oil palms and
exposed dry leaf litter in 2-mm and 37-μm mesh bags within a plantation. The finer mesh allowed microbial
access but restricted roots and most detritivores.
We measured litter mass loss, carbon and nitrogen
dynamics, and fungal communities via ITS barcoding
over six months. Root ingrowth and soil chemistry
were also analyzed.
Results Litter mass decreased by 70% in both mesh
types, with soil accumulating litter-derived 15N. Fine
roots grew into the mesh after three months and took
up 15N, demonstrating nitrogen recycling. Fungal succession
displayed clear temporal patterns: early colonizers
thrived with higher C/N ratios (Hypocreales,
Pleosporales, Chaetothyriales), while late colonisers
(e.g., Sordariales, Pleosporales, Chaetosphaeriales) correlated with C degradation. Arbuscular mycorrhizal
fungi increased with declining C/N ratios and
coincided with root growth.
Conclusions Oil palm litter enhances nitrogen
availability, fosters AMF diversity, and improves
degraded soils. The numerous uncharacterized fungi
in litter decomposition highlight the need for further
research into their functional roles for sustainable soil
restoration
Differential effects of marimastat and prinomastat on the metalloprotease activity of various snake venoms
No full textSnakebite envenoming is a neglected tropical disease, responsible for approximately 140,000 deaths globally each year. Vipers and elapid snakes represent the most significant snake families in medical contexts, exhibiting a variety of venom components and clinical effects in bite victims. Metalloproteases, a primary component of venoms, are mainly accountable for haemotoxic and myotoxic effects. Although predominantly found in viper venoms, these enzymes are also present in varying levels in elapid snake venoms. Marimastat and prinomastat are matrix metalloprotease inhibitors initially developed as cancer therapies. Recently, extensive research has focused on these inhibitors to neutralise venom metalloproteases. However, their effects on different viper and elapid snake venoms remain unclear. Here, we report the sensitivity of seven elapid venoms (specifically, cobras) and 12 viper venoms to marimastat and prinomastat, utilising selective in vitro experiments and molecular docking analyses performed using representative metalloprotease (VAP2, a viper metalloprotease from the venom of Crotalus atrox and an elapid metalloprotease from the venom of Naja atra) structures. Both compounds inhibited the metalloprotease, fibrinogenolytic, and caseinolytic activities of most viper venoms. While prinomastat displayed prominent inhibitory effects on cobra venoms in these assays, marimastat demonstrated limited inhibitory effects on these venoms. These findings illustrate the role of matrix metalloprotease inhibitors in modulating metalloprotease activities across a range of viper and cobra venoms. Collectively, this study establishes the differential effects of marimastat and prinomastat on various levels of metalloproteases present in viper and elapid venoms. This will enhance understanding of the abundance of metalloproteases in snake venoms and their sensitivity to different matrix metalloprotease inhibitors
Exploring Kuwait middle school teachers’ and technical supervisors’ perceptions of in-service training and its effectiveness in developing teachers’ teaching and learning
No full textThis study examined the perceptions of Kuwaiti middle school classroom teachers and
technical supervisors regarding INSET programmes. In doing so it provided insights into the
nature and quality of INSET programmes designed by Kuwait’s Ministry of Education (MoE),
potentially informing strategies and initiatives to enhance the effectiveness of teachers’
professional development in the Kuwaiti context.
The study employed a mixed methods case study approach comprising questionnaires and
semi-structured interviews to investigate perceptions of the effectiveness of these
programmes, the support provided to teachers, teachers’ motivation and engagement, and
challenges hindering programme effectiveness. Its sample was drawn from middle school
mathematics and science teachers and from technical supervisors from multiple schools in one
school district in Kuwait. A total of 139 teachers responded to the questionnaires, while 15
teachers and 10 technical supervisors participated in the semi-structured interviews.
The data revealed that participants’ perceptions of the effectiveness of INSET programme
content were based on content focus, active learning, coherence, duration, and collective
participation. Study findings also highlighted that while several forms of support – namely
administrative support, resource accessibility, follow-up, and the soliciting of feedback and
evaluation – are provided for middle school teachers' professional development in Kuwait, the
amount of support given and its contribution to teachers' learning and practice is often
variable. The findings further indicated that the main factors affecting middle school teachers’
motivation to engage in INSET were personal factors, and environmental/contextual factors
(including, school factors, relevance and impact, and learning environment). The most
prominent challenges that participants perceived to the effectiveness of INSET programmes
related to programme design and delivery, motivation and engagement, and post-training
follow-up. Additionally, the study findings indicated a clear failure on the part of the MoE to
prioritise teachers’ professional development and the need for it to create standardised
frameworks for conducting and evaluating INSET and other professional development
initiatives for teachers. Addressing these problematic areas could render INSET programmes
more responsive to teachers’ needs, thereby improving teachers’ professional development in
Kuwaiti middle schools and enhancing overall teaching and learning outcomes
Risk storylines: a community-led discussion between disaster and climate science
Get PDFAn international workshop brought together researchers and practitioners to exchange experiences in developing and applying climate and disaster risk storylines. Discussions focused on integrating quantitative and qualitative evidence and on expanding storylines to include nonclimatic risk drivers such as exposure, vulnerability, and their underlying drivers. The event featured a dynamic blend of high-level keynote talks, case studies, practical sessions, and poster presentations. Participants engaged in lively discussions, shared insights, and collaborated on hands-on activities aimed at developing actionable risk storylines
EEGAP: ECC-based Efficient Group Authentication Protocol for dynamic vehicular platoon
No full text— Vehicular platooning has emerged as a promising paradigm in intelligent transportation, offering significant
benefits such as reduced energy consumption, improved road
throughput and mitigated traffic congestion. However, the open
nature of vehicular communication channels exposes platoons
to a wide range of security and privacy threats. Although
existing group key-based protocols provide foundational security
services, they often incur substantial computation overhead and
insufficiently address vehicle privacy, making them unsuitable
for dynamic vehicular platoon. Therefore, this paper introduces
an efficient group authentication protocol (EEGAP) for dynamic
vehicular platoons, which ensures privacy-preserving and secure
communication during platoon restructuring operations, such as
merging and splitting, by integrating anonymous authentication,
fog computing, and group key agreement mechanisms. Leveraging Elliptic Curve Cryptography (ECC) and secret sharing
mechanisms, EEGAP enables lightweight yet robust group key
negotiation, reducing computation overhead by 7.08% and communication overhead by 6.85% compared to existing schemes.
Both formal security proofs and informal analysis confirm that
EEGAP satisfies the stringent security requirements of vehicular
platoon communication systems
The impacts of climate change on aircraft noise near European airports
No full textThe warmer air resulting from climate change reduces the lift force on a departing aircraft, potentially reducing its climb angle and causing more engine noise near the airport. Here, we study this phenomenon at a selection of 30 European airports in northern hemisphere summer (June–July–August). We first formulate and verify a low-complexity model of noise propagation around airports, although we emphasise that our high-level results do not explicitly depend on this agreement. The model includes anisotropic noise propagation, atmospheric absorption, and the ability to model the noise emissions from multiple engines. We study the Airbus A320, but the method could be straightforwardly generalised to other aircraft. We refer to the model as an emulator since (using Latin hypercube parameter sampling) it mimics a more comprehensive model against which it is verified. The model is used to calculate the area enclosed by the 50 dB SPL (sound pressure level) contour, A50, which agrees well with a similar metric (using the day–evening–night sound level, Lden) from the verification target, A. Using temperature and pressure data from IPCC simulations of future climate, and using a straightforward relation between climb angle and air density, we assess how climate change could affect climb angles by mid-century (2035–2064). The value of A50 is obtained by efficiently covarying (1) the engine noise at 10 m from the engines and (2) the climb angle under ‘historical’ conditions (1985–2014). The median values (across 10 climate models) of climb angle reduction in the future warmer climate are around 1–3% (depending on the airport and climate model used), but individual days can show values as high as 7.5% for the most extreme warming scenarios. By considering the variation in the absorption coefficient of the air with frequency, we find that the number of people affected by noise pollution could increase by up to 4%—as much as 2500 people for the most highly populated areas—by mid-century and that these changes are maximised for the most damaging and psychologically ‘annoying’ (low) frequencies
Effects of raspberry leaf tea polyphenols on postprandial glucose and insulin responses in healthy adults
Get PDFBackground: Dietary polyphenols, particularly flavonoids, have been associated with improved glycemic control and reduced risk of type 2 diabetes. Raspberry leaf (RL) is a rich but underexplored source of such bioactives, including ellagitannins, flavonoids, and phenolic acids. While raspberry fruit has received some attention in nutritional science, the metabolic effects of raspberry leaf—especially its influence on postprandial glucose and insulin responses—remain largely unstudied. Objective: This study is the first to investigate the acute effects of RL tea consumption on postprandial blood glucose and insulin levels in healthy individuals following intake of common dietary carbohydrates (sucrose and glucose). Methods: In a randomized crossover study, 22 healthy adults (12 males, 10 females) consumed 50 g of glucose or sucrose with or without 10 g of RL tea in four separate sessions. Blood glucose and insulin levels were measured at fasting and at 15, 30, 60, 90, and 120 min post-ingestion. A total of 37 polyphenolic compounds were identified in the RL infusion using LC–MS, following a 5-minute hot water extraction. The contents of ellagitannins, flavonoids, and phenolic acids were 38 mg, 7 mg, and 4 mg per 10 g of RL, respectively, contributing to a total polyphenol content of 50 mg per 10 g. Results: When RL tea was consumed with sucrose, postprandial blood glucose levels were significantly reduced at 15 and 30 min by 1.19 ± 0.88 mmol/L (25.59% reduction, p = 0.001) and 2.03 ± 1.05 mmol/L (43.57% reduction, p = 0.0004), respectively. Insulin concentrations were also significantly lower at 15 min (113.90 ± 59.58 pmol/L, p = 0.019), 30 min (161.76 ± 91.96 pmol/L, p = 0.0008), and 60 min (139.44 ± 75.96 pmol/L, p = 0.025). No significant differences were observed with glucose ingestion. Conclusions: This study provides the first clinical evidence that RL tea can blunt early postprandial glycemic and insulinemic responses to sucrose in healthy individuals. The data suggest that these effects are likely mediated by relatively low levels of polyphenols—particularly ellagic acid—through inhibition of carbohydrate-digesting enzymes such as α-glucosidase and β-fructofuranosidase. These findings support the potential of RL tea as a simple, dietary approach to modulate glucose metabolism and warrant further investigation in populations at risk for metabolic disorders
Optimal strategies for estimating the parameters of the Baranyi-Ratkowsky model: from (optimal) experiment design to model fitting methods
Get PDFThe Baranyi growth model combined with the Ratkowsky secondary model (Baranyi-Ratkowsky hereafter) has demonstrated their reliability for describing microbial growth as a function of temperature. However, these models are based on empirical parameters that must be estimated from data, so robustness depends on the experimental design and the model fitting approach. This study applies a rigorous statistical analysis based on Information Theory and numerical simulations to provide clear guidelines on the best model fitting approaches and experimental designs for the Baranyi-Ratkowsky model.
First, the study concludes that one-step fitting approaches result in lower parameter dispersion than two-steps approaches (for the simulated conditions: 44 %, 85 % and 96 % lower for
,
and
, respectively, no reduction for
and
). Numerical simulations demonstrate that, unlike for two-steps methods, the error of regression from the one-step approach is a realistic estimate of parameter uncertainty/variability, strengthening the case for this method. This motivates restricting the calculation of Optimal Experiment Designs (OEDs) for this approach only. The study clearly demonstrates that the experimental design has a clear impact on parameter dispersion. However, OEDs tend to be impractical, as they focus on conditions that require long experimental runs. Accordingly, a penalty term is introduced in OED definition, resulting in two strategies: to lower the number of experiments at lower temperatures, and to terminate the experiments at lower temperatures before reaching stationary phase. Based on this result, we propose a staggered experimental design that is updated recursively (storage temperature and position of time points) until convergence. Considering that isothermal experiments are still the gold standard in the field, future studies could greatly benefit from these suggestions by minimizing the experimental effort needed to obtain robust estimates for the Baranyi-Ratkowsky model