The damage of fiber reinforced polymer matrix composite materials induced by impact load is one of the most critical factors that restrict extensive use of these materials. The behavior of composite ...structures under transient impact loading and the ways to enhance their characteristics to withstand this type of dynamic loading might be of specific significance in the aerospace sector and other applications. This paper critically reviews the important parameters from the published literature influencing the impact resistance and the damage mechanics of fiber-reinforced composite materials. Firstly, the paper reviews the influence of impact velocity on various failure modes. Following this, a comprehensive review on the four key parameters specifically material, geometry, event and the environmental-related conditions that affect the structural behavior of fiber reinforced polymer matrix composites to impact loading is discussed. The review further outlines areas to improve the impact damage characteristics of composites and then conclude with a summary of the discussion on the future work relating to the most influencing parameters.
Marine bivalves include economically highly important aquacultured species worldwide (oysters, mussels, clams, scallops). Although one third of production in Europe is represented by mussels (Mytilus ...edulis, M. galloprovincialis) a significant decline has been observed in the last two decades, whose causes are likely to be multifactorial, from the presence of pathogens to climate change, often exacerbated by local conditions, leading to mortality outbreaks.
Knowledge of the composition of the microbial communities, together with their relationship with the host, represents a primary target for understanding bivalve health in different environmental conditions. The microbiome is strongly influenced by both local environmental factors and endogenous factors, such as the host immune status. However, information on the seasonal fluctuations of microbial communities in mussels, together with immune parameters, is still lacking.
In the present work, M. galloprovincialis cultivated in north-western Italy (La Spezia) were sampled from February to November 2020 and hemolymph microbiome was evaluated using 16S rRNA gene, together with a set of immune biomarkers in hemocytes (lysosomal membrane stability-LMS, phagocytic activity, ROS production) and soluble lysozyme activity, and parameters of general health conditions (gametogenesis, survival in air).
The results show that M. galloprovincialis hemolymph microbiota was characterized by the constant presence of 8 bacterial genera (Vibrio, Pseudoalteromonas, Tenacibaculum, Colwellia, Shewanella, Amphritea, and 2 from the Arcobacteracea family, Halarcobacter and Arcobacter-like). Seasonal changes in their relative abundance were observed, showing a distinct pattern in winter (February–November) and summer (July, September). Water temperature contributed to shaping the microbiota composition, in particular with regards to the abundance of Vibrios, Psychrilobacter and Photobacterium, Halarcobacter and Arcobacter-like, that was favored by higher temperatures. Seasonal variations of LMS and phagocytosis were also observed, indicating a reduced immunocompetence in winter, concomitant with general stressful conditions associated with spawning. In contrast, the main fluctuations in extracellular immune defences (ROS and lysozyme) were apparently independent of temperature or gametogenic stage. Overall, the results confirm the robustness of mussel immune system, at the same time underlying the potential susceptibility to disease at certain times of the year to additional stressful conditions (i.e. pathogen challenge, pollutant exposure, or further changes in water chemico-physical parameters). These data provide background information useful for monitoring local mussel farming and predicting potential impacts of changing environmental conditions.
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•Study on Mytilus galloprovincialis from an aquaculture site in northwestern Italy.•First data on seasonal changes in hemolymph microbiota and host immune defences.•Increased Vibrio abundance with water T, lower immune defences in winter.•Background info on mussel health status in face of future environmental changes.
Entrepreneurship is multifaceted. The purpose of this review is to acknowledge and critically assess the many and varied dependent variables (DVs) of entrepreneurship over the last 17 years. By ...focusing exclusively on systematically reviewing entrepreneurship’s DVs, this paper maps out, classifies, and provides order to the phenomena that scholars consider part of this self-defined field of research. Using a systematic selection process and an inductive approach to categorization, we offer a meta-framework for organizing entrepreneurship’s DVs. On the basis of this meta-framework, entrepreneurship involves the (a) initiation, (b) engagement, and (c) performance of entrepreneurial endeavors embedded in (d) environmental conditions in which an entrepreneurial endeavor is the investment of resources into the pursuit of a potential opportunity. For each category, we offer both a review of the different DVs and opportunities for future research.
A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how ...the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat, by examining the benefits of heat acclimation, cooling strategies and hyperhydration. Finally, contemporary controversies are summarized and future research directions provided.
Our ability to interrogate and manipulate the genome far exceeds our capacity to measure the effects of genetic changes on plant traits. Much effort has been made recently by the plant science ...research community to address this imbalance. The responses of plants to environmental conditions can now be defined using a variety of imaging approaches. Hyperspectral imaging (HSI) has emerged as a promising approach to measure traits using a wide range of wavebands simultaneously in 3D to capture information in lab, glasshouse, or field settings. HSI has been applied to define abiotic, biotic, and quality traits for optimisation of crop management.
Hyperspectral imaging captures both spectral (λ) and spatial (x, y) information and merges these into a 3D data matrix termed a ‘hyperspectral data cube’ (hypercube).A 3D hyperspectral data cube consists of 2D of spatial information plus one spectral dimension that contains information for hundreds of spectral bands.Hyperspectral imaging has been applied to detect abiotic, biotic, and quality traits in plants in indoor and outdoor growing conditions.Hyperspectral imaging can be applied from a cellular to landscape scale to determine plant traits.Data processing and mining tools are still evolving, with machine learning and deep learning algorithms being used in order to assist scientists in predicting traits.
Extreme environmental conditions, such as heat, salinity, and decreased water availability, can have a devastating impact on plant growth and productivity, potentially resulting in the collapse of ...entire ecosystems. Stress-induced systemic signaling and systemic acquired acclimation play canonical roles in plant survival during episodes of environmental stress. Recent studies revealed that in response to a single abiotic stress, applied to a single leaf, plants mount a comprehensive stress-specific systemic response that includes the accumulation of many different stress-specific transcripts and metabolites, as well as a coordinated stress-specific whole-plant stomatal response. However, in nature plants are routinely subjected to a combination of two or more different abiotic stresses, each potentially triggering its own stress-specific systemic response, highlighting a new fundamental question in plant biology: are plants capable of integrating two different systemic signals simultaneously generated during conditions of stress combination? Here we show that plants can integrate two different systemic signals simultaneously generated during stress combination, and that the manner in which plants sense the different stresses that trigger these signals (i.e., at the same or different parts of the plant) makes a significant difference in how fast and efficient they induce systemic reactive oxygen species (ROS) signals; transcriptomic, hormonal, and stomatal responses; as well as plant acclimation. Our results shed light on how plants acclimate to their environment and survive a combination of different abiotic stresses. In addition, they highlight a key role for systemic ROS signals in coordinating the response of different leaves to stress.
•The initial moisture content in CFRP tendons affects significantly the Tg values.•CFRP specimens without initial moisture content should be used for quality control.•Plasticisation effects in CFRP ...tendons due to exposure in water are reversible.•The fire performance of CFRP tendons can be affected by the initial moisture content.•The magnitude of static flexural strain and specimen geometry do not affect the Tg.
The high temperature and long-term performance of uni-directional pultruded carbon fibre reinforced polymer (CFRP) tendons in prestressed concrete relies on the integrity of the epoxy matrix and the degree of crosslinking. The dynamic glass transition temperature (Tg) obtained using Dynamic Mechanical Analysis (DMA) can be a useful indicator of the degree of cross-linking. However, variations in the epoxy plasticisation due to different initial hygrothermal equilibrium conditions in CFRP tendons can influence the measured Tg leading to inconsistent results. The dependency of Tg on the initial CFRP moisture content, and also DMA test parameters including the thermocouple position, the magnitude of static flexural strain, the static to dynamic strain ratio and the specimen geometry were investigated. Whereas the selected DMA test parameters had only a small influence on the Tg values, the initial moisture content of the CFRP tendon had a significant effect. A decrease in Tg of up to 38 °C was observed with an increase in average moisture content of up to 2.46%. Knowledge of the initial moisture content and the establishment of a comparative baseline are necessary to more accurately infer the crosslinking density and degree of cure of a resin from dynamic Tg results.
For centuries, bird guano has played a pivotal role in the agricultural and economic development of Latin America, East Asia and Oceania. As their populations ballooned during the Industrial ...Revolution, North American and European powers came to depend on this unique resource as well, helping them meet their ever-increasing farming needs. This book explores how the production and commodification of guano has shaped the modern Pacific Basin and the world's relationship to the region. Marrying traditional methods of historical analysis with a broad interdisciplinary approach, Gregory T. Cushman casts this once little-known commodity as an engine of Western industrialization, offering new insight into uniquely modern developments such as environmental consciousness and conservation movements; the ascendance of science, technology and expertise; international relations; and world war.
Using specially trained canines in forensic analysis to identify individual human scents is a well-established method, capitalizing on dogs' exceptional olfactory abilities. This study investigates ...the survival of human scent under extreme weather conditions in the Kingdom of Bahrain. Five experienced German Shepherd police dogs, trained for human scent tracking, participated in the experiments. The study was conducted during Bahrain's hot summer season, characterized by high temperatures, high humidity, and occasional strong winds. Three common surfaces—sand, grass, and asphalt—were selected to represent scenarios where human scent might be detected.
The findings revealed that human scent persisted for approximately 8–11 hours on sand and grass but only 1–3 hours on asphalt, highlighting the impact of surface type on scent survival. The research also examined the effect of temperature on scent survival, testing at three different temperatures: 30°C, 40°C, and 50°C. The results demonstrated that scent durability varied across types of articles and temperature conditions. For instance, at 30°C, human scent remained detectable for up to 93 days on leather but only 27–28 days on silk cloth. At 40°C, leather allowed the scent to last 64–65 days, while wood surfaces had the shortest duration. The scent lasted 37–39 days on jeans cloth at a temperature of 50°C but only 3–4 days on wood. The data gathered can be beneficial for forensic investigations in semi-desert areas involving canine olfaction, offering guidance on the timing and likelihood of scent detection.
•The human scent dynamics for forensic canine analysis in Bahrain’s weather is studied.•Human scent lasted for 8–11 h on sand and grass but 1–3 hours on asphalt.•Temperature had impacted human scent survival on different articles.•Timing and probability of scent detection vary with the environmental conditions.•Evidence supports the role of canine scent detection in forensic investigations within semi-desert areas.
Rise of Turfs FILBEE-DEXTER, KAREN; WERNBERG, THOMAS
BioScience/Bioscience,
02/2018, Letnik:
68, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Kelp forests are structurally complex habitats, which provide valuable services along 25% of the world’s coastlines. Globally, many kelp forests have disappeared and been replaced by turf algae over ...the last decade. Evidence that environmental conditions are becoming less favorable for kelps, combined with a lack of observed recovery, raises concern that these changes represent persistent regime shifts. Here, we show that human activities mediate turf transitions through geographically disparate abiotic (warming and eutrophication) and biotic (herbivory and epiphytism) drivers of kelp loss. Evidence suggests kelp forests are pushed beyond tipping points where new, stabilizing feedback systems (sedimentation, competition, and Allee effects) reinforce turf dominance. Although these new locks on the degraded ecosystems are strong, a mechanistic understanding of feedback systems and interactions between global and local drivers of kelp loss will expose which processes are easier to control. This should provide management solutions to curb the pervasive trend of the flattening of kelp forests globally.
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