Potential Source Of Disturbance Research Articles

Face Mask Wastes as Cementitious Materials: A Possible Solution to a Big Concern.

After more than two years wearing surgical masks due to the COVID-19 pandemic, used masks have become a significant risk for ecosystems, as they are producing wastes in huge amounts. They are a potential source of disturbance by themselves and as microplastic contamination in the water system. As 5500 tons of face masks are estimated to be used each year, there is an urgent need to manage them according to the circular economy principles and avoid their inadequate disposal. In this paper, surgical wear masks (WM), without any further pretreatment, have been introduced as addition to mortars up to 5% in the weight of cement. Mechanical and microstructural characterization have been carried out. The results indicate that adding MW to the cement supposes a decrease in the properties of the material, concerning both strength and durability behavior. However, even adding a 5% of WM in weight of cement, the aspect of the mortars is quite good, the flexural strength is not significantly affected, and the strength and durability parameters are maintained at levels that—even lower than the reference—are quite reasonable for use. Provided that the worldwide production of cement is around 4.1 Bt/year, the introduction of a 5% of WM in less than 1% of the cement produced, would make it possible to get rid of the mask waste being produced.

Species, tree size, and overstory environment affect likelihood of ice storm damage to understory trees in a mature Douglas-fir forest

Abstract Glaze events (i.e., ice storms) are a potential source of disturbance whose effects have not been heavily researched in forests in the Pacific Northwest. This study examines the effects of species, size, and overstory environment on occurrence, source, and severity of damage sustained by planted understory trees in a mature Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) forest as a result of the glaze event that struck the central Oregon Coast Range in November 2014. Understory tree species were Douglas-fir, grand fir ( Abies grandis (Douglas ex D. Don) Lindl.), western hemlock ( Tsuga heterophylla (Raf.) Sarg.), and western redcedar ( Thuja plicata Donn ex D. Don). Overall, western redcedar was damaged least frequently, and western hemlock was damaged most frequently. Redcedar was less susceptible to crown damage and more susceptible to bending damage than the other three species, while hemlock showed the opposite trend. We found significantly lower (P

The modelling and assessment of whale-watching impacts

In recent years there has been significant interest in modelling cumulative effects and the population consequences of individual changes in cetacean behaviour and physiology due to disturbance. One potential source of disturbance that has garnered particular interest is whale-watching. Though perceived as ‘green’ or eco-friendly tourism, there is evidence that whale-watching can result in statistically significant and biologically meaningful changes in cetacean behaviour, raising the question whether whale-watching is in fact a long term sustainable activity. However, an assessment of the impacts of whale-watching on cetaceans requires an understanding of the potential behavioural and physiological effects, data to effectively address the question and suitable modelling techniques. Here, we review the current state of knowledge on the viability of long-term whale-watching, as well as logistical limitations and potential opportunities. We conclude that an integrated, coordinated approach will be needed to further understanding of the possible effects of whale-watching on cetaceans.

Spatial genetic structure of dusky dolphin, Lagenorhynchus obscurus, along the argentine coast: preserve what scale?

Abstract The dusky dolphin (Lagenorhynchus obscurus) represents one of the most abundant species of small cetacean in Argentine waters. During the 1980s and 1990s, high levels of incidental mortality in purse and trawl fisheries were documented, and in recent decades tourism activities have been added as a potential source of disturbance. The study objectives were to identify spatial genetic structure and regional genetic patterns of dusky dolphins along the Argentine coast. The variation of 413bp of the control region of 119 individuals over six locations spread along 2800 km (38°40'S to 54°30'S) was examined. Spatial genetic analyses, SAMOVA, genetic landscape shapes and autocorrelation analyses were conducted. The most probable configuration was K=2, island population vs. continental populations (FCT = 0.774) and the spatial autocorrelation analysis showed a strong regional genetic structure, defining an operational unit at < 50 km. The results provide valuable information that should be taken into account in the development of conservation strategies and management of the species; making the efforts focus on conserving vulnerable dusky dolphin groups by protecting their preferred coastal shallow habitat and by monitoring and regulating the dolphin watching and fishing activities, acting upon local populations along the Argentine coast. Copyright © 2015 John Wiley & Sons, Ltd.

Tropical tree community shifts: Implications for wildlife conservation

In tropical forest systems tree community change after initial succession (approximately 50–100 years) is very difficult to detect because of the very slow pace of transformation. Since the mid 1980s, there has been an accumulation of evidence that many forests traditionally considered old growth or mature forests have been disturbed. Using 18 years of data on forest change in Kibale National Park, Uganda, we tested the following hypotheses. Species that frequently recruit only into areas of large-scale disturbance (e.g., conversion to agriculture) (1) have a more strongly negative annualized rate of population change (i.e., recruitment is less than mortality) than trees recruiting into the understory or canopy treefall gaps and (2) these species are declining in their average cumulative diameter at breast height (DBH). Both hypotheses were verified. We then examined relationships between forest change and diets of the five diurnal primates in Kibale. The emergent patterns suggest that forest change will lead to declines in some species, particularly the black-and-white colobus ( Colobus guereza). We concluded that what was considered mature forest in Kibale has actually been disturbed in the recent past, and we discuss how potential sources of disturbance (dry-periods, elephant population fluctuations, and human disturbance) may affect both forest change and animal populations. We assess how such information might be useful in forest management.

Non-indigenous marine macroalgae in native communities: a case study in the British Isles

It has traditionally been considered that areas with high natural species richness are likely to be more resistant to non-indigenous species than those with lower numbers of species. However, this theory has been the subject of a debate over the last decade, since some studies have shown the opposite trend. In the present study, a macroalgal survey was carried out at 24 localities in Northern Ireland and southern England, using a quadrat approach in the lower littoral. The two opposing hypotheses were tested (negative versus positive relationship between native and non-indigenous species richness) in this marine environment. The effect of the presence of ‘impacts’, potential sources of disturbance and species introduction (e.g. marina, harbour or aquaculture), was also tested. A positive relationship was found between the number of non-indigenous species and the native species richness at the three different scales tested (quadrats, sites and localities). At no scale did a richer native assemblage appear to restrict the establishment of introduced species. The analyses revealed greater species richness and different community composition, as well as more non-indigenous species, in southern England relative to Northern Ireland. The presence of the considered impacts had an effect on the community composition and species richness in southern England but not in Northern Ireland. Such impacts had no effect on the non-indigenous species richness in either area.

Towards a New Philosophy in the Prevention Strategy on Health and Safety at Work

The current prevention policy continues to be reactive. It is even negative and demotivating. This atmosphere is destroying the working conditions we need in our new social-economic environment. Quality of work has become top of the agenda together with creativity, personal development and involvement. The human being is transformed from a potential source of disturbance into an essential success factor. A new approach to prevention policy is imposing itself in this context. Caring for safety, health and well-being of the employees at the same time means caring for the well-being and the future of the organization. The great challenge now becomes the development of the human potential. In that perspective a real proactive prevention policy is needed. Proactivity implies prevention but goes much further. Real proactivity refers to the dreams and positive objectives people wish to see realised. Well-being, participation and empowerment of all participants are important targets while the expected implications for culture are commitment, trust and open communication. This approach is very close to the conditional factors of social quality as described in the report of the European Foundation on the European Network Indicators of Social Quality.

Can Quality Assurance Survive the Market? Accreditation and Audit at the Crossroads

This article provides a comparative analysis of the systems used for the ‘accreditation’ of degree-granting institutions in the USA (accreditation) and the UK (audit). The authors begin by outlining the similarities and differences between the two processes. They point out that audit is not the subject of political controversy in the way that accreditation currently is. However, they add that this does not necessarily mean that all is set fair and potential sources of disturbance are highlighted. The article then considers what changes can be expected in the two processes as a result of increased market pressures, and whether such changes will make them more effective vehicles for quality improvement. An alternative approach, which would involve merging the regulatory role of the QAA with the regulatory functions of the Funding Councils, as part of a complete scheme of risk assessment, is suggested. The article also asks to whom the accrediting agencies in both countries are accountable for their work. According to the authors, neither process is foolproof; both can be manipulated and are open to abuse. In addition, it is argued that on neither side of the Atlantic are there currently adequte arrangements to “inspect the inspectors”. The authors conclude by warning that with the growing tendency to resort to the legal process, more questions will be asked about the accountability of those whose judgements are being questioned. In their view, the stronger the market pressures, the greater will be the recourse to legal process in both countries.

Sediment disturbance off the Tagus Estuary, Western Portugal: chronic contamination, sewage outfall operation and runoff events

Sediment disturbance patterns in the coastal area off the Tagus Estuary (Portugal) have been assessed using a set of combined techniques. The potential sources of disturbance in the area include chronic contamination of the fine sediments originating from the estuary, a local input from a long-sea sewage outfall and occasional high runoff episodes following torrential rain. The Sediment Quality Triad approach, combining environmental chemistry (namely organic contaminants), macrofaunal benthic communities and laboratory sediment toxicity assays, was performed on sediment samples from 20 sites. The samples were collected before the outfall commenced operation and four years after commissioning, in order to evaluate the relative magnitudes of the three potential sources of disturbance. The sediment contamination created by the estuary was identified as the most important cause of reduced sediment quality, as disturbance in all three components of the Sediment Quality Triad were only found in a site located near the estuary.

A review of the distribution and status of Pygmy Palm-Swift Micropanyptila furcata in Venezuela

Pygmy Palm-Swift Micropanyptila furcata is endemic to the Maracaibo Basin of Venezuela and Colombia. Described by Sutton in 1928, it is still known only from < 30 museum specimens from seven localities, leading it to be included in the first edition of the bird Red Data Book, but not subsequent editions. During a field survey in January 1995 we regularly encountered this species throughout the south-eastern Maracaibo Basin in Venezuela, at elevations from 30 m to 800 m. We found them in a variety of habitats including cleared pastures, cropland, open forest and rural towns, and observed them near mature cultivated palms, which represented nesting and roosting substrates. Pygmy Palm-Swifts foraged in small groups immediately above the treetops and over grass savannah. As we recorded them at nearly all previously known sites and many additional ones, often in close proximity to human activities and potential sources of disturbance, we suggest that it is not a rare bird and currently does not require special status or conservation efforts.

Experiments on effects of sampling biota under intertidal and shallow subtidal boulders

Diverse assemblages of sessile and mobile fauna live under intertidal and subtidal boulders. When these biota are sampled, it is necessary temporarily to overturn the boulders. Many mobile species respond to overturning by moving onto the other side of the boulder or moving off the boulder into the surrounding area. Overturning without replacing a boulder has been shown to affect abundances and diversity of its sessile and mobile organisms. Overturning when sampling has, however, not previously been examined as a potential source of disturbance, because replacement of the boulders has been assumed not to disturb the organisms. These experiments were designed to test the hypothesis that sampling is a measurable disturbance to the mobile fauna and groups of sessile biota living under boulders. The sessile organisms were mainly encrusting algae, encrusting tubeworms and bryozoans, with smaller amounts of foliose algae, other colonial animals, bivalves and cnidarians. The mobile fauna were primarily large (> 5 mm long) chitons, gastropods and echinoderms. Assemblages on boulders that had been previously sampled were compared to those on undisturbed boulders. Effects of sampling on temporal changes in abundances were also compared to similar changes on sets of undisturbed boulders. There were no or very few differences in assemblages, mean densities of selected species or the proportions of boulders occupied by selected species among undisturbed boulders and boulders subjected to different frequencies of prior sampling when there were 3–4 month intervals between samples. There were, however, short-term responses to disturbance associated with sampling. These were measured as differences in densities and the proportion of boulders occupied by some species of molluscs and echinoderms and differences in the molluscan assemblage between undisturbed and disturbed, i.e. previously sampled, boulders. These differences disappeared during the following month. These data suggest that organisms on boulders are disturbed by careful sampling, but that they rapidly recover during the following few weeks. Thus, sampling is possible without altering the abundances of the target species if there is long enough between samples for the densities under the disturbed boulders to recover.

THE ENVIRONMENTAL MONITORING OF NATURAL EVENTS AND INDUSTRY ACTIVITY IN MERMAID SOUND, DAMPIER ARCHIPELAGO

Various events, both natural and man-induced, have been identified as potential sources of disturbance to corals adjacent to the North West Shelf Project's Onshore Gas Treatment Plant on the Burrup Peninsula in the Dampier Archipelago. These events include cyclones, dredging and dredge spoil dumping operations, shipping activities, effluent discharge and oil spills.Environmental monitoring has indicated that the coral assemblages near the Onshore Gas Treatment Plant have been adversely affected by Project-related operations and tropical cyclones. The effects on corals due to dredging and spoil dumping activities have been shown to be localised and limited to a distance of 1.5 km from the nearest point of operation.Cyclone Ilona (1988) and Cyclone Orson (1989) were amongst the strongest recorded in the Dampier Archipelago. These cyclones caused extensive coral damage throughout the Archipelago, especially on the eastern side of Mermaid Sound. By 1990, recruitment of corals was observed at many of the sites indicating that corals were beginning to recover.

Reevaluation of the conventional triaxial test methods : Baldi, G; Hight, D W; Thomas, G E Proc Symposium on Advanced Triaxial Testing of Soil and Rock, Louisville, 19–20 June 1986P219–263. Publ Philadelphia: ASTM, 1988 (ASTM Special Technical Publication 977)

A practical reevaluation of some aspects of conventional triaxial test methods is made, based on Bishop and Henkel's book The Measurement of Soil Properties in the Triaxial Test (2nd ed., Edward Arnold, London, 1962). Some advances in measurement techniques, methods of preparing, installing and saturating specimens, and the measurement of the initial effective stress are discussed, with particular emphasis on potential sources of disturbance and methods to reduce this. The use of unconsolidated undrained tests and various stress paths in relation to current needs is represented.

A new method for using fluorescein to demonstrate oto- and rhinoliquorrhea. I. Sample preparation by electrophoresis and photometric identification of fluorescein.

We have described a new method for the identification of sodium fluorescein in cases of cerebrospinal fluid (CSF) leakage. To take samples, small sponges of Merocel are placed into the nostrils or external auditory canal, as indicated. They are left in situ for 12h after intrathecal injection of 5% sodium fluorescein. Fluorescein is identified by electrophoretic separation on 1% agarose gel and demonstration with the fluorescence photometer. This method of testing has various advantages: the use of small sponges enables collections of minimal amounts of CSF; potential sources of disturbance (e.g. hemoglobin, etc.) are eliminated; false-positive results are avoided; the time needed for sample analysis lasts only 10 min. All necessary materials and equipment, as well as the taking and analysis of samples, are described in detail. The method used was tested both clinically on patients and in the laboratory and its sensitivity is clearly illustrated.

THE PROBLEM OF THE THYMUS IN CHILDREN

The thymus gland has for a long time been a subject for study by physiologists.1It appears to many clinicians, however, that this organ is cited only when convenient to account for an otherwise inexplicable symptom, or even death. Thus the critical physician frequently wishes there were no such thing as the thymus and denies that it has any clinical implications. The thymus exists, however, and it cannot be entirely disregarded as a potential source of disturbance in early life, even though it has been too often incriminated by uncritical diagnosticians and too frequently treated by enthusiastic therapeutists. There will be considered in this presentation three ways in which the pediatrician meets the problem of the thymus, the type of encounter varying at the different stages of the child's development. THYMIC HYPERPLASIA The pediatrician may be called to see a young infant suffering from such symptoms as respiratory stridor,