446 research outputs found

    Exploring the potential for adopting alternative materials to reduce marine plastic litter

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    The ocean has become a repository for an increasing quantity of plastics and microplastics. This has been matched, in recent years, by growing awareness of the social, economic and environmental impacts that this phenomenon is causing. There is widespread recognition that urgent action is required to reduce the leakage of plastics to the ocean, but that there is no simple solution. It is clear that the traditional linear production, use and disposal model for conventional plastics is not sustainable and results in unacceptable harm. This requires the development and implementation of more closed-loop, or circular, production models. But there is scope for assessing whether there are alternative solutions that minimise the use of conventional plastics for applications in which they are not essential. The purpose of this study was to assess the potential of replacing conventional plastics with alternative materials in certain applications, as part of a wider strategy of reducing marine plastic litter and microplastics. The target audience is governments and businesses. This may appear a daunting task, given the ubiquity of plastics in our daily lives, described in Chapter 2, so it seemed sensible to identify certain categories of plastics that may prove more amenable to reduction or replacement. Following an assessment of the most common items reported in field surveys (Chapter 3) it was decided to focus part of the study on 'single-use' plastic waste from single-use packaging and consumer products intended for short-term use, such as food and drink containers, given the preponderance of these categories in surveys of ocean plastics, especially in shoreline debris. Another common feature of microplastics identifed in surveys of biota, sediments and seawater is the abundance of micro-fbres. Micro-fibres on shorelines, especially near urban centres, consist mostly of textile fibres and this provided a second focus for the study

    Movement of Crude Oil in an Experimental Spill on the SEEDS Simulated Pipeline Right-of-way, Fort Norman, N.W.T.

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    The Studies of the Environmental Effects of Disturbances in the Subarctic (SEEDS) experimental spill was conducted on a simulated pipeline right-of-way and trench. A total of 3273 L of Norman Wells crude oil was released over a 24 h period at a depth of 100 cm in a simulation of a rupture from a subsurface pipeline. Absorptive qualities of the surface vegetation and organic soil layers in an undisturbed forest produce rates of flow and area of contamination values much lower than the SEEDS experiment. Furthermore, the area of contamination (672.75 sq m) was greater than experiments in which the amount of oil and rates of pumping were larger. This resulted from the presence of surface water, a depressed mineral soil-dominated simulated pipeline trench, a cleared right-of-way and slow pumping rates. The SEEDS experiment was a more valid analogue of crude-oil spills associated with a buried pipeline in a subarctic environment.

    The complications of alcoholism: an epidemiological, statistical and nutritional study on alcoholics admitted to a general hospital psychiatric unit

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    1) A study of alcoholics admitted to a general hospital psychiatric unit over a period of 4 years (527 males and 148 females) is presented. The various demographic, social and drinking characteristics are given and the male and female alcoholics are compared. The complications and associated physical conditions were studied epidemiologically and with special reference to blood vitamin levels in an attempt to elucidate their aetiology. A follow-up study was carried out to find the causes of death in these patients and at the same time the prognosis studied to ascertain its relationship to these complications.2) There were more alcoholics in social classes I, II and 7 and in the widowed and divorced. The age pattern of alcoholics was similar to other studios with an almost normal distribution curve around the mean of 43.7 years in males and 45.4 years in females. The religion of the patients was similar to that of the surrounding area.3) Over half of the alcoholics were admitted as emergencies} a quarter did not finish the course of in-patient treatment and one-fifth of the total were re-admitted during the four year period.4) Whisky was the preferred drink among male alcoholics and "fortified wine" among females. The former had been drinking for considerably longer than the latter (a mean of 16.2 years compared to 9.9 years) and they drank, on average, much more, (the equivalent of a bottle of whisky a day compared to the equivalent of a bottle of sherry per day).5) A quarter of all the patients were given an associated psychiatric diagnosis of which most were in the personality disorder group.6) There was a large incidence of behavioural disturbance, so that only one-third of men, but two-thirds of women, had no previous convictions. However more women (33%) than men (18%) had previous suicide attempts and more abused drugs than men (25% compared to 11%.7) Male and female alcoholics were shown to have a number of differences especially in drinking habits noted above. Female alcoholics were older, and they were admitted via other hospital wards or by Alcoholics Anonymous, They stayed longer in hospital and were admitted more frequently. They had more spouses who were alcoholic than males. They showed more evidence of malnutrition in the form of weight loss and clinical signs of nutritional disease and they had a higher incidence of alcoholic dementia and of the "rare" neuropsychiatric disorders. They had a lower incidence of alcoholic epilepsy, delirium tremens, alcoholic hallucinosis and E.E.G. abnormalities, as well as hepatitis and previous gastric operations, but similar incidences of cirrhosis, neuropathy and anaemia8) Only 18% of patients had no associated physical condition. Almost one-fifth of the patients had each of the following: anaemia, peripheral neuropathy, gastritis, hepatitis, severe withdrawal signs and E.C.G. abnormalities and one-tenth had cirrhosis. These results are very similar to other studies despite differences in drinking habits and social class. There were only 8 patients who had had previous venereal disease and 4 who had previous pancreatic disease.9) There was no objective evidence of withdrawal in 40% of the patients, on the other hand 20% had severe effects including delirium tremens. Alcoholics with delirium tremens tended to have associated cirrhosis, anaemia, peripheral neuropathy and epilepsy, as well as abnormal levels of whole blood thiamine and serum folate.More female patients had alcoholic dementia which was related to increased age, increased length of excess drinking and peripheral neuropathy as well as subnormal whole blood thiamine and nicotinic acid levels.Alcoholic epilepsy was associated with delirium tremens and with drug abuse, abnormal levels of S.G.O.T., S.G.P.T., serum proteins, whole blood thiamine and serum folate levels.Alcoholic hallucinosis was associated only with paranoid psychosis though there were more patients in this group with raised S.G.O.T. levels and low whole blood thiamine levels.Thus the alcoholic psychoses as a whole appear to have a relationship to nutritional factors.10) Peripheral neuropathy was associated with delirium tremens, cirrhosis and dementia. Food intake was poorer in these patients and on admission they had more evidence of wight loss, whole blood thiamine levels were low in 70% of the patients and there was an increase of abnormal protein levels. These findings confirm that nutritional factors are of importance in the condition, but there was also a relationship with the increased daily amount of alcohol, especially of fortified wine, and with the length of time of excess alcohol intake .`11) Whereas cirrhosis was related to delirium tremens, peripheral neuropathy, alcoholic cardiomyopathy and E.C.G. abnormalities, acute liver disease was related to no other physical condition. Similarly an increased number of cirrhotics load abnormal whole blood thiamine levels which were not found in patients with acute liver disease. Patients with cirrhosis were older and had been drinking for longer than other alcoholic patients.12) Gastritis, diagnosed on clinical grounds, was found in 17% of these alcoholics, was only related in male patients to various behavioral abnormalities. Most patients with gastric operations, found in 11% of male alcoholics and 4.5% of female alcoholics had their operations years after the start of heavy drinking. There was evidence of an increased incidence of peptic ulceration in these alcoholics.15) Alcoholic cardiomyopathy was present in only nine male alcoholics, all of whom had been drinking to excess for over 20 years and had a heavy daily intake of alcohol. However 113 patients were shown to have E.C.G. abnormalities usually of a minor degree.14) Anaemia was found in one-fifth of the patients, but was varied in nature, though in two-thirds of female alcoholics and a half of male alcoholics it was iron deficient in type. It was associated with increased alcohol intake, especially "crude spirits". Nutritional factors were important and there was an association with cirrhosis and delirium tremens.15) Female alcoholics were shown to have more evidence of nutritional deficiencies on most of the parameters utilised than male alcoholics. It would seem that nutritional deficiency is important in delirium tremens, alcoholic dementia, alcoholic epilepsy, cirrhosis and peripheral neuropathy.16) The average length of follow-up was four years, 10% of patients were untraced. Twenty-five per cent of patients were found to be improved, 20% worsened and 10% had died. The indicators of good prognosis were those in social classes I and II compared to social class V, decreased length of drinking and absence of behavioral abnormalities. Female patients did no better than male patients.17) Hale patients died mainly from cirrhosis, cardiovascular or respiratory disorders, including carcinoma of the bronchus, whereas females were much more likely to commit suicide.18) There were many associated physical and behavioral abnormalities in this group of alcoholic in-patients. No clear pattern as to exact aetiology of the different conditions emerged though nutritional factors appear to play a part in the conditions which are classically considered to be the "complications" of alcoholism

    Plant Diversity and Cover after Wildfire on Anthropogenically Disturbed and Undisturbed Sites in Subarctic Upland Picea mariana Forest

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    Postfire development of cover and diversity was studied in an upland Picea mariana-dominated forest in the Canadian Subarctic. Short-term vegetation responses of 10- and 22-year-old cleared rights-of-way and a forest site were investigated two and three growing seasons after a wildfire. Prefire and postfire investigation of the study site allowed direct comparison of species cover and frequency values, as well as the Shannon-Wiener diversity index, before and after the fire. The fire considerably reduced diversity on all sites. Species diversity increased with the level of prefire disturbance. Prefire disturbance influenced the fire's characteristics by altering the fuel load and soil moisture, which in turn affected the postfire revegetation through different soil and microclimatic conditions. The sites that were most severely disturbed before the fire experienced the most rapid revegetation, including the highest diversity index and highest plant cover. Of the sites that were undisturbed before the fire, the natural drainage swales offered the best growing conditions after the burn. Furthermore, prefire disturbance increased the patchiness of the burned area, and the residual flora of unburned patches added to postfire floristic diversity.On a étudié le développement du couvert et de la diversité après un incendie dans une forêt de haute terre dominée par Picea mariana, au Canada subarctique. Les réactions à court terme des plantes poussant dans les emprises dégagées vieilles de 10 et 22 ans, ainsi qu'un site forestier ont été l'objet de recherches deux et trois saisons de croissance après un incendie de forêt. Les travaux réalisés sur le site de l'étude avant et après le feu ont permis une comparaison directe du couvert et de la fréquence des espèces ainsi que de l'index de diversité Shannon-Wiener avant et après le feu. L'incendie a considérablement réduit la diversité sur tous les sites. La diversité des espèces augmentait avec le niveau de perturbation existant avant l'incendie. La perturbation pré-incendie a influencé la nature du feu en modifiant la masse de combustible et l'humidité du sol, qui, à leur tour, ont affecté le reverdissement post-incendie en modifiant l'état du sol et les conditions microclimatiques. Les sites qui avaient été le plus perturbés avant le feu ont connu le reverdissement le plus rapide, y compris l'index de diversité et le couvert végétal les plus élevés. Parmi les sites qui n'avaient pas été perturbés avant l'incendie, les dépressions de drainage naturelles offraient les meilleures conditions de croissance après le feu. De plus, la perturbation pré-incendie a intensifié le morcellement de la surface brûlée, et la flore résiduelle des parcelles non brûlées a ajouté à la diversité floristique présente après l'incendie

    Vegetation Response to a Subsurface Crude Oil Spill on a Subarctic Right-of-way, Tulita (Fort Norman), Northwest Territories, Canada

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    The plant species on a simulated pipeline corridor near Tulita (Fort Norman), Northwest Territories were studied prior to and for three years after an experimental point-spill of 3273 L (20 imperial barrels) of crude oil. Two distinct environments were examined: a cleared right-of-way (ROW) and a simulated pipeline trench. Each environment was subdivided on the basis of oil concentration into heavily oiled, lightly oiled, and unoiled sections. Total plant cover on the heavily oiled ROW declined by 73% in the first growing season; however, significant recovery took place in subsequent years. All other oiled environments had significant increases in total plant cover, but not until at least the second year after the spill. Of the 34 taxa identified, 13 declined significantly in abundance by the third growing season after the oil spill, mainly on the heavily oiled ROW. By the third post-spill growing season, mosses, Carex spp., Eriophorum spp., and agronomic grasses (Alopecurus arundinacea, Phleum pratense, Poa glauca and P. pratensis) had increased in abundance on at least one type of oiled substrate. However, the agronomic grasses, species sown on the Norman Wells pipeline, also declined significantly on the heavily oiled Trench. In contrast, the native grass Arctagrostis latifolia declined only on the heavily oiled ROW.On a étudié les espèces végétales présentes sur un corridor pipelinier simulé près de Tulita (Fort Norman), dans les Territoires du Nord-Ouest, avant un déversement expérimental ponctuel de pétrole brut de 3273 L (soit 20 barils impériaux) et durant les trois années suivantes. On a examiné deux environnements distincts: une emprise dégagée et une tranchée simulée de pipeline. On a divisé chaque environnement en sections en se basant sur la concentration en pétrole: forte, faible et nulle. Durant la première saison de croissance, l'ensemble du couvert végétal a diminué de 73 p. cent sur les sections de l'emprise où existait une forte concentration; un important reverdissement a toutefois pris place durant les années suivantes. Tous les autres endroits qui avaient reçu du pétrole ont connu d'importantes augmentations de l'ensemble du couvert végétal, mais, au plus tôt, à partir de la deuxième année suivant le déversement. Sur les 34 taxons identifiés, 13 avaient largement diminué en abondance à la troisième saison de croissance suivant le déversement, surtout dans les sections de l'emprise à forte concentration de pétrole. À la troisième saison de croissance suivant le déversement, les mousses des espèces Carex et Eriophorum et les herbes agronomiques (Alopecurus arundinacea, Phleum pratense, Poa glauca et P. pratensis) avaient augmenté en abondance à au moins un type de milieu où avait été déversé du pétrole. Toutefois, les herbes agronomiques - espèces semées sur le parcours du pipeline de Norman Wells - avaient aussi diminué de façon significative sur la tranchée où se trouvait une forte concentration de pétrole. Par contre, l'herbe indigène Arctagrostis latifolia n'avait diminué que sur l'emprise à forte concentration

    Pollution in the open oceans: 2009-2013

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    This review of pollution in the open oceans updates a report on this topic prepared by GESAMP five years previously (Reports and Studies No. 79, GESAMP, 2009). The latter report, the first from GESAMP focusing specifically on the oceans beyond the 200 m depth contour, was prepared for purposes of the Assessment of Assessments, the preparatory phase of a regular process for assessing the state of the marine environment, led jointly by the United Nations Environment Programme (UNEP) and the Intergovernmental Oceanographic Commission (UNESCO-IOC)

    Use of summer habitat by caribou on the north slope of a mountain near the Macmillan Pass, N.W.T.

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    Habitat use by woodland caribou was investigated by counting pellet-groups, sampling phytomass, and evaluating topography in nine habitat-types on the north slope of an unnamed mountain near Macmillan Pass, N.W.T. Caribou pellets were most abundant in high elevation habitat-types, and pellet density was greatest in an alpine Lichen-Grass habitat-type with a slope of <1°. The high density of pellets in alpine areas may have resulted from of the use of cool, windy, alpine habitats by caribou seeking relief from insect harassment. There were no apparent relationships between pellet abundance, and phytomass of mosses, lichens, or graminoids, possibly as a result of caribou feeding and defecating in different habitats. The occurrence of pellets with a coalesced morphology in the barren Lichen-Grass habitat-type provided indirect evidence in support of a feeding cycle, whereby caribou visit lush habitats to feed, and return to open, alpine habitats to rest and ruminate

    Radial-Growth Response of Forest-Tundra Trees to Climate in the Western Hudson Bay Lowlands

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    The effects of climate on radial growth of Larix laricina (Du Roi) K. Koch, Picea glauca (Moench) Voss, and Picea mariana (Mill) BSP were investigated in the Hudson Bay Lowlands of northern Manitoba. The objective was to characterize spatial and temporal variations in growth of trees across the forest-tundra ecotone. Along a 250 km transect, 299 trees were sampled in three zones: northern forest, central tundra, and southern forest. Ring-width indices were compared with climate through correlation- and response-function analyses. Numerous years of suppressed growth at the three locales resulted from cooling that followed major volcanic eruptions at much lower latitudes. Temperatures during July of the current year and autumn of the previous year were most limiting, particularly for L. laricina, which was temperature-sensitive across the region. A weakened growth response to temperature during the 1940–60 period was likely due to atmospheric circulation shifts. Most chronologies were intercorrelated, which suggests common environmental forcing, though environmental influences differed in the southern forest (particularly for P. mariana). The source of this disparity has yet to be determined.Les effets du climat sur la croissance radiale de Larix laricina (Du Roi) K. Koch, de Picea glauca (Moench) Voss et de Picea mariana (Mill) BSP ont fait l’objet d’une étude dans les basses-terres de la baie d’Hudson, au nord du Manitoba. L’objectif de cette étude consistait à caractériser les variations spatiales et temporelles en matière de croissance des arbres à l’échelle de l’écotone de la toundra forestière. Le long d’un transect de 250 km, 299 arbres ont été échantillonnés dans trois zones : la forêt septentrionale, la toundra centrale et la forêt méridionale. Les indices de la largeur des cernes ont été comparés aux données climatiques au moyen d’analyses de corrélation et de fonction de réponse. De nombreuses années de croissance affaiblie aux trois endroits découlaient du refroidissement ayant suivi d’importantes éruptions volcaniques à des latitudes beaucoup moins élevées. Les températures enregistrées en juillet de l’année courante et à l’automne de l’année précédente étaient plus restrictives, particulièrement dans le cas de L. laricina, qui était sensible aux températures dans toute la région. La réponse de croissance affaiblie enregistrée par rapport aux températures au cours de la période allant de 1940 à 1960 était vraisemblablement attribuable aux décalages de circulation atmosphérique. La plupart des chronologies ont fait l’objet d’inter-corrélations, et celles-ci laissent entrevoir un forçage environnemental courant, bien que les influences environnementales différaient dans la forêt méridionale (particulièrement dans le cas de P. mariana). La source de cette disparité n’a toujours pas été déterminée. Mots clés : dendroclimatologie, toundra forestière, Churchill, largeur des cernes, Picea glauca, Picea mariana, Larix laricina, parc national Wapusk, fonction de réponse, basses-terres de la baie d’Hudso

    The Shelter Characteristics of Traditional-styled Inuit Snow Houses

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    The shelter value of snow iglus at Resolute (74 41 N, 94 54 W) in the Canadian High Arctic was assessed. After a survey of snow conditions, construction sites were chosen and two iglus were built and furnished in a traditional way. A large iglu (4.1 m diameter) contained 72 blocks averaging 23.6 kg and had a surface area-to-volume ratio of 2.21:1. A smaller iglu (3.05 m in diameter) contained 46 blocks averaging 28.2 kg and had a surface area-to-volume ratio of 1.73:1. The smaller iglu provided 75% of the large iglu's space for 76.5% of its mass. Snow hardness averaged 12000 g/sq. cm, and the mean density of the snow was 397 kg per cu m. The energy required to build and heat each iglu was calculated from the snow characteristics, construction activities and microclimate parameters measured during occupancy. Heat flux was calculated for human bodies, kudliks (seal oil lamps), and geothermal sources at temperature differentials as high as 45 C from ambient, for both the unlined large iglu and the small iglu, which was lined with caribou skins on the inside. The smaller iglu was more efficient, requiring the fat of one seal every 6.3 days for heating, while the large iglu required the fat of one seal every 3.7 days. The meat content of each seal would have sustained a family of four for the same time interval, and the resultant body heat would have provided 8% to 14% of the total energy necessary to maintain comfortable temperatures within the iglu.On a évalué la valeur de la protection offerte par les igloos de neige à Resolute (74° 40' de latit. N.) dans l'Extrême-Arctique canadien. On a d'abord procédé à un relevé de l'état de la neige, puis choisi les sites et construit et équipé deux igloos de façon traditionnelle. Soixante-douze blocs de neige pesant en moyenne 23,6 kg ont servi à construire le grand igloo (4,1 m de diamètre) dont le rapport surface:volume était égal à 2,21. Quarante-six blocs pesant en moyenne 28,2 kg ont servi à la construction du petit igloo dont le rapport surface:volume était égal à 1,73. Ce petit igloo représentait 75 p. cent de l'espace du grand igloo pour 76,5 p. cent de sa masse. La dureté de la neige était en moyenne de 12 000 g/cm² et sa densité moyenne de 397 kg/m³. On a calculé l'énergie nécessaire pour construire et chauffer chaque igloo à partir des caractéristiques de la neige, des activités relatives à la construction et des paramètres du microclimat mesurés au cours de l'occupation. On a calculé le flux thermique pour les corps, les kudliks (lampes à l'huile de phoque) et les sources géothermiques à des différences de température allant jusqu'à 45 °C au-dessus de la température ambiante, et ce, pour le grand igloo nu et pour le petit qui, lui, était tapissé de peaux de caribou sur les parois internes. Le petit igloo était le plus éconergétique, ne consommant pour le chauffage que la graisse d'un phoque tous les 6,3 jours alors que le grand igloo en consommait autant tous les 3,7 jours. La viande de chaque phoque aurait assuré la subsistance d'une famille de quatre personnes au cours des mêmes périodes, et la chaleur animale qui en aurait résulté aurait fourni de 8 à 14 p. cent de l'énergie totale nécessaire pour maintenir une température confortable dans l'igloo

    Investigating the Molecular Orientation and Thermal Stability of Spiro‐OMeTAD and its Dopants by Near Edge X‐Ray Absorption Fine Structure

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    This study describes the utilization of near edge X-ray absorption fine structure (NEXAFS) to investigate the hole transporting material (HTM) 2,2ʹ,7,7ʹ-tetrakis(N,N-di-p-methoxyphenylamine)- 9,9ʹ-spirobifluorene (Spiro-OMeTAD) and its most common dopants, lithium bis-(trifluoromethylsulfonyl) imide (LiTFSI), 4-tert-butylpiridine (tBP), and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ). By changing the angle of the sample with respect to the beam, the orientation of the molecules on the surface can be observed. The data suggest that it is difficult to determine any orientational preference for Spiro-OMeTAD deposited on a surface due to the 3D propeller-like geometry of this molecule. Both doped and undoped samples show thermal stability beyond the glass transition temperature of the molecules. Significant changes to the Spiro-OMeTAD spectra are observed with the addition of the dopants, in particular the C K-edge. Differences are also observed in the valence band spectra when dopants are added. It is also demonstrated how the doping combination of LiFTSI with tBP and, F4-TCNQ act as p-type dopants by altering the position of the HOMO levels. The F4-TCNQ induces a larger change in the HOMO levels when compared to the LiTFSI and tBP. These results are important to increase the understanding of Spiro-OMeTAD and the effect dopants have on this material for next generation solar cells
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