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Over 50 years ago, a marine estuary was converted to a wastewater stabilization basin for treatment of primarily pulp and paper effluent. As a result, the basin was immediately converted to a 'freshwater' environment and subsequently accumulated a thin layer of black, organic-rich sediment containing varying amounts of dioxins and furans, metals, polycyclic aromatic hydrocarbons, and petroleum hydrocarbons. Previous studies on the site have shown that the majority of this contamination in the basin appears to have been contained within this black sediment layer and not migrated to any significant extent into the original underlying marine sediments. The purpose of this study is to examine sediment porewater chemistry changes that have occurred over 51 years of operation of the stabilization basin with the intent of better understanding why contamination has been minimal into the underlying natural marine sediments. Field and laboratory testing is presented to characterize the physical, chemical, and mineralogical sediments in the basin. Porewater chemistry profiles obtained from this work are then used in combination with a one-dimensional contaminant transport model to examine the role of diffusion, sorption, and upward groundwater flux in the porewater profiles found for the sediments. Key words: contaminant migration, diffusion, sorption, barrier, pulp and paper Il y a plus de 50 ans, un estuaire marin a ete converti en bassin de stabilisation des eaux usees pour le traitement d'effluents principalement issus du secteur de la pate a papier. En consequence, le bassin a ete immediatement converti en un environnement << d'eau douce >> et a ensuite accumule une fine couche de sediments noirs, riches en matieres organiques, contenant des quantites variables de dioxines et de furanes, de metaux, d'hydrocarbures aromatiques polycycliques et d'hydrocarbures petroliers. Des etudes anterieures sur le site ont montre que la majorite de cette contamination dans le bassin semble avoir ete contenue dans cette couche de sediments noirs et n'a pas migre de maniere significative dans les sediments marins sousjacents originaux. Le but de cette etude est d'examiner les changements de la chimie de l'eau interstitielle des sediments qui se sont produits au cours des 51 annees d'exploitation du bassin de stabilisation dans l'intention de mieux comprendre pourquoi la contamination a ete minimale dans les sediments marins naturels sous-jacents. Des essais sur le terrain et en laboratoire sont presentes pour caracteriser les sediments physiques, chimiques et mineralogiques du bassin. Les profils chimiques des eaux interstitielles obtenus a partir de ce travail sont ensuite utilises en combinaison avec un modele unidimensionnel de transport des contaminants pour examiner le role de la diffusion, de la sorption et du flux ascendant des eaux souterraines dans les profils des eaux interstitielles trouves pour les sediments. [Traduit par la Redaction] Mots-cles : migration des contaminants, diffusion, sorption, barriere, pate et papier, 1. Introduction Boat Harbour (BH) is the stabilization basin, which until 2020, comprised part of a wastewater treatment facility located near Pictou, Nova Scotia, Canada. A tidal estuary until 1967, [...]

Palynomorphs are one of the few groups of fossils that provide biostratigraphic control in marine to nonmarine rocks and can be applied as proxies for paleoenvironmental and paleoclimatic interpretations. Their utility is enhanced by their microscopic size, which is usually less than 200 micrometres; they are thus easily recovered from small rock samples. They occur throughout the Phanerozoic and are therefore invaluable in refining biostratigraphic control of Arctic successions in Alaska, Arctic Canada, Greenland, northern Europe, and northern Russia. The objective of the Circum-Arctic Palynological Event (CAPE) Stratigraphy series of papers is to integrate data published on Arctic palynomorphs to delineate palynological events (palynoevents) across the Arctic for the Silurian to Cenozoic. Once the series of papers is complete, the data will also be used to compile a TimeScale Creator datapack that can be updated and calibrated on an ongoing basis. Palynoevents include taxon originations (first occurrences or FOs) and extinctions (last occurrences, or I.Os) and some abundance events. The palynoevents are correlated with established chronostratigraphic horizons such as bases of ammonoid zones or stages, and hence their chronostratigraphy is independent of the absolute time scale in millions of years. In addition to the palynostratigraphic papers, the series includes a paper detailing the paleogeography of the circum-Arctic regions, including informative maps, as well as a paper providing a palynological perspective of the Cenozoic shift from greenhouse to icehouse conditions. Les palynomorphes sont l'un des rares groupes de fossiles qui permettent un controle biostratigraphique dans les roches marines et non marines et qui peuvent servir de temoins pour les interpretations paleoenvironnementales et paleoclimatiques. Leur utilite se trouve amelioree par leur taille microscopique, qui est habituellement de moins de 200 micrometres; ils sont ainsi facilement recuperes des petits echantillons de roches. Ils sont presents durant tout le Phanerozoique et sont par consequent d'une valeur inestimable pour le raffinement du controle biostratigraphique des successions arctiques en Alaska, dans l'Arctique canadien, au Groenland, dans le nord de l'Europe et dans le nord de la Russie. La serie d'articles sur la stratigraphie des phenomenes palynologiques circumarctiques (PPC) vise l'integration des donnees publiees sur les palynomorphes arctiques afin de degager les phenomenes palynologiques (palynophenomenes) dans l'Arctique durant la periode du Silurien au Cenozoique. Une fois la serie d'articles terminee, les donnees serviront a la compilation d'un dossier de donnees TimeScale Creator pouvant etre mis a jour et etalonne de facon continue. Les palynophenomenes englobent les apparitions (premieres manifestations ou PM) et les extinctions (dernieres manifestations ou DM) de taxons, et certains phenomenes d'abondance. Les palynophenomenes sont correles avec des horizons chronostratigraphiques etablis comme les bases de zones ou d'etages d'ammonites, et leur chronostratigraphie est done independante de l'echelle chronologique absolue en millions d'annees. Outre les articles palynostratigraphiques, la serie comprend un article detaillant la paleogeographie des regions circumarctiques, y compris des cartes informatives, ainsi qu'un article fournissant une perspective palynologique du passage d'une periode a effet de serre a des conditions a faible effet de serre durant le Cenozoique. [Traduit par la redaction], INTRODUCTION In the Circum-Arctic Palynological Event Stratigraphy project (CAPE), specialists were asked to document selected palynological events (for example taxon originations and extinctions) with correlation potential from the Silurian to [...]

A summer course developed at Purdue University leverages students' intrinsic desire to observe tornadoes as a motivator for learning severe storms forecasting. Relative to previous 'storm chasing' courses, the Students [...]

ABSTRACT Several important developments in the 1960s showed the way to using spectral analysis to identify and describe atmospheric waves predicted by theory. Among these waves were normal-mode Rossby-Haurwitz waves [...]

Schetselaar, A., Andersen, T., and Burn, C.R. Performance of Climate Projections for Yukon and Adjacent Northwest Territories, 1991-2020. Jarstad, E., Felberg, H.A., and Mamen, A. A Case of the Short-term [...]

En aquest article es presenten les activitats i experiències impulsades des de la Cartoteca de Catalunya amb l'objectiu de visibilitzar i reconèixer els treballs de les dones en un camp tradicionalment amb una gran presència d'homes, com són les ciències de la terra. Les dues activitats principals se centren en la celebració d'exposicions per donar difusió al fons propi de la Cartoteca, i a intentar desenvolupar col·leccions més equilibrades des del punt de vista de gènere. This article describes the activities designed by the Map Library of Catalonia to draw attention to the contributions of women to Earth sciences, a field traditionally dominated by men. The Library’s two main lines of action are the organization of exhibitions to bring its holdings to a wider public, and its project to develop more gender-balanced collections.

Strongman, A. The Influence of Butterflies and Bees on the Old Bering Sea Visual Art. Mills, S., Simmons, D., and Williamson, K.J. In Pursuit of 'a Good Life': Inuit Qaujimajatuqangit [...]

ABSTRACTS The 2016/17 wildfire season in Chile was the worst on record, burning more than 600,000 ha. While wildfires are an important natural process in some areas of Chile, supporting [...]

The Madden-Julian oscillation (MJO) identified by Madden and Julian in the early 1970s has been well recognized as the most prominent intraseasonal signal in the tropics. Its discovery and its [...]

The Semi-Arid Land-Surface-Atmosphere Program (SALSA) is a multi-agency, multi-national research effort that seeks to evaluate the consequences of natural and human-induced environmental change in semi-arid regions. The ultimate goal of SALSA is to advance scientific understanding of the semi-arid portion of the hydrosphere-biosphere interface in order to provide reliable information for environmental decision making. SALSA approaches this goal through a program of long-term, integrated observations, process research, modeling, assessment, and information management that is sustained by cooperation among scientists and information users. In this preface to the SALSA special issue, general program background information and the critical nature of semi-arid regions is presented. A brief description of the Upper San Pedro River Basin, the initial location for focused SALSA research follows. Several overarching research objectives under which much of the interdisciplinary research contained in the special issue was undertaken are discussed. Principal methods, primary research sites and data collection used by numerous investigators during 1997-1999 are then presented. Scientists from about 20 US, five European (four French and one Dutch), and three Mexican agencies and institutions have collaborated closely to make the research leading to this special issue a reality. The SALSA Program has served as a model of interagency cooperation by breaking new ground in the approach to large scale interdisciplinary science with relatively limited resources.

R.M. QUIGLEY AWARDThe R.M. Quigley Award is given out each year to the best paper published in Canadian Geotechnical Journal (CGJ) in the previous year. Bob Quigley was one of [...]

Zeolites were synthesized from paper-sludge ash in different alkali solutions. The ash used in this study has a high-Ca content and a low abundance of Si, in part due to the presence of calcite that is used as a paper filler. The major minerals present in the ash are gehlenite ([Ca.sub.2][Al.sub.2]Si[O.sub.7]) and anorthite (Ca[Al.sub.2][Si.sub.2][O.sub.8]). Three kinds of alkali solutions (NaOH, KOH, and LiOH) at four different concentrations (1, 2, 3, and 4 M) were reacted with paper-sludge ash at 90[degrees]C for 24 h. Powder X-ray diffraction showed that hydroxysodalite ([Na.sub.6][Al.sub.6][Si.sub.6][O.sub.24] x [8H.sub.2]O and zeolite Linde F (KAlSi[O.sub.4] x [1.5H.sub.2]O) had formed in NaOH and KOH solutions, respectively, and that anorthite had dissolved in these alkaline solutions, whereas gehlenite had remained unaffected. In the LiOH solution, both anorthite and gehlenite dissolved, and various minerals, including Li-ABW zeolite ([Li.sub.4][Al.sub.6][Si.sub.6][O.sub.16] x [4H.sub.2]O), hydrocalumite [[Ca.sub.2]Al[(OH).sub.6](Cl, OH) x [3H.sub.2]O], tobermorite [Ca.sub.5][Si.sub.6][O.sub.16][(OH).sub.2] x [4H.sub.2]O], katoite [[Ca.sub.3][Al.sub.2](Si[O.sub.4])[(OH).sub.8]], and portlandite [Ca[(OH).sub.2]] formed. The products of mineral synthesis from paper-sludge ash by reaction in alkaline solutions strongly depend on the specific alkali present. Keywords: Paper-sludge ash, hydroxysodalite, zeolite Linde F, Li-ABW, hydrocalumite, tubermorite, katoite, portlandite

Crawford, A., and Mueller, D. Assessing Ice Island Drift Patterns, Ice Island Grounding Locations, and Gridded Bathymetry Products between Nares Strait and the North Atlantic. Parrett, J.P., Prichard, A.K., Johnson, [...]

New York City College of Technology has created a year-round geoscience workforce preparation and geoscience career mentoring program for nongeoscience, minority science, technology, engineering, and math (STEM) students beginning at [...]

Background: Paper mulberry (Broussonetia papyrifera (L.) L'Hér. ex Vent) is a dioecious tree native to East Asia and mainland Southeast-Asia, introduced prehistorically to Polynesia as a source of bark fiber by Austronesian-speaking voyagers. In Oceania, trees are coppiced and harvested for production of bark-cloth, so flowering is generally unknown. A survey of botanical records of paper mulberry revealed a distributional disjunction: the tree is apparently absent in Borneo and the Philippines. A subsequent study of chloroplast haplotypes linked paper mulberry of Remote Oceania directly to a population in southern Taiwan, distinct from known populations in mainland Southeast-Asia. Methodology: We describe the optimization and use of a DNA marker designed to identify sex in paper mulberry. We used this marker to determine the sex distribution in selected localities across Asia, Near and Remote Oceania. We also characterized all samples using the ribosomal internal transcribed spacer sequence (ITS) in order to relate results to a previous survey of ITS diversity. Results: In Near and Remote Oceania, contemporary paper mulberry plants are all female with the exception of Hawaii, where plants of both sexes are found. In its natural range in Asia, male and female plants are found, as expected. Male plants in Hawaii display an East Asian ITS genotype, consistent with modern introduction, while females in Remote Oceania share a distinctive variant. Conclusions: Most paper mulberry plants now present in the Pacific appear to be descended from female clones introduced prehistorically. In Hawaii, the presence of male and female plants is thought to reflect a dual origin, one a prehistoric female introduction and the other a modern male introduction by Japanese/Chinese immigrants. If only female clones were dispersed from a source-region in Taiwan, this may explain the absence of botanical records and breeding populations in the Philippines and Borneo, and Remote Oceania. [ABSTRACT FROM AUTHOR]

Stirling, I., Regehr, E.V., Spencer, C., Burns, L.E., and Laidre, K.L. Using Visual Observations to Compare the Behavior of Previously Immobilized and Non-Immobilized Wild Polar Bear. Dawson, J., Cook, A., [...]

Glass, T.W., Breed, G.A., Laird, C.R., Magoun, A.J., Robards, M.D., Williams, C.T., and Kielland, K. Terrain Features and Architecture of Wolverine (Gulo gulo) Resting Burrows and Reproductive Dens on Arctic [...]

Kvern, M., Fitzpatrick, P., and Fishback, L.A. Empowering Churchill: Exploring Energy Security in Northern Manitoba. Pigford, A.-A.E., Hickey, G.M., and Klerkx, L. Networked Relationships for Science-Informed Innovation in the Arctic: [...]

Prichard, A.K., Welch, J.H., and Lawhead, B.E. The Effect of Traffic Levels on the Distribution and Behavior of Calving Caribou in an Arctic Oilfield. Seguin, R., Lefsrud, M.G., Delormier, T., [...]

Aagard, Troels Aitken, Alec Akoglu, Ahmet Allard, Michel Ansdell, Kevin Archibald, Donnelly Arnaud, Emmanuelle Atkinson, Gail Averianov, Alexander Azizi, Hossain Baird, Graham Barendregt, Rene Barr, Sandra Bauer, Bernard Bedard, Jean [...]

The action required to stem the environmental and social implications of climate change depends crucially on how humankind shapes technology, economy, lifestyle and policy. With transport CO2 emissions accounting for about a quarter of the total, we examine the contribution of CO2 output by scientific travel. Thankfully for the reputation of the scientific community, CO2 emissions associated with the trips required to present a paper at a scientific conference account for just 0.003% of the yearly total. However, with CO2 emissions for a single conference trip amounting to 7% of an average individual’s total CO2 emissions, scientists should lead by example by demonstrating leadership in addressing the issue. [ABSTRACT FROM AUTHOR]

Quantifying the impact of a scholarly paper is of great significance, yet the effect of geographical distance of cited papers has not been explored. In this paper, we examine 30,596 papers published in Physical Review C, and identify the relationship between citations and geographical distances between author affiliations. Subsequently, a relative citation weight is applied to assess the impact of a scholarly paper. A higher-order weighted quantum PageRank algorithm is also developed to address the behavior of multiple step citation flow. Capturing the citation dynamics with higher-order dependencies reveals the actual impact of papers, including necessary self-citations that are sometimes excluded in prior studies. Quantum PageRank is utilized in this paper to help differentiating nodes whose PageRank values are identical. [ABSTRACT FROM AUTHOR]

This section is placed at the beginning of a manuscript and must convey everything presented: what the research was about, where, why, and how it was conducted, and what it means relative to the current state of knowledge. It should consist of one paragraph of 250 or fewer words (i.e., no more than 3% of length of manuscript). Abstracts always are written in the past tense, thus, the best quality abstracts are written after the remainder of the manuscript is finished. Bibliographic services publish only the title and abstract of manuscripts. When conducting a literature search, researchers may read abstracts of perhaps 100 s of papers in which the titles possibly have bearing on an aspect of their work. Only if the content of the abstract seems relevant, will researchers progress to reading the article from which the abstract was derived. Therefore, great care must be used to write an abstract so it correctly reflects the contents of the manuscript in a precise and concise manner that can stand alone. Furthermore, it must contain no figures, tables, or references to them, or material not presented in the body of the manuscript; except for critique papers, no literature citations should be included. Also, it should not contain acronyms or jargon, even with definitions, not readily known to the general reading audience of the publication in which the manuscript will be published., INTRODUCTION This section should include a well-ordered compilation of published information, with necessary literature citations that lead to the 'why' of the research being conducted and reported to the scientific [...]

This section is placed at the beginning of a manuscript and must convey everything presented: what the research was about, where, why and how it was conducted and what it means relative to the current state of knowledge. It should consist of one paragraph of 250 or fewer words (i.e., no more than 3% of length of manuscript). Abstracts always are written in the past tense, thus, the best quality, abstracts are written after the remainder of the manuscript is finished. Bibliographic services publish only the title and abstract of manuscripts. When conducting a literature search, researchers may read abstracts of perhaps 100s of papers in which the titles possibly have bearing on an aspect of their work. Only if the content of the abstract seems relevant will researchers progress to reading the article from which the abstract was derived. Therefore, great care must be used to write an abstract so it correctly reflects the contents of the manuscript in a precise and concise manner that can stand alone. Furthermore, it must contain no figures, tables or references to them, or material not presented in the body of the manuscript; except for critique papers, no literature citations should be included. Also, it should not contain acronyms or jargon, even with definitions, not readily known to the general reading audience of the publication in which the manuscript will be published.

R.M. QUIGLEY AWARD The R.M. Quigley Award is given out each year to the best paper published in Canadian Geotechnical Journal (CGJ) in the previous year. Bob Quigley was one [...]

Paper mulberry, Broussonetia papyrifera (L.) L’Hér. ex Vent. (Moraceae), a dioecious species, was transported by humans from Taiwan to the islands of Remote Oceania. Its introduction and cultivation in Remote Oceania was intentional due to its cultural importance as a fiber source for barkcloth textiles. The aim of this study was to explore the genetic diversity and structure of paper mulberry populations within Remote Oceania in order to infer dispersal patterns that may reflect past human interaction among island groups. We present the integrated analysis of 380 samples (313 contemporary and 67 herbarium specimens) collected in Near and Remote Oceania. Genetic characterization was based on a set of ten microsatellites developed for B. papyrifera and complemented with the analysis of the ribosomal internal transcribed spacer ITS-1 sequence, a sex marker and the chloroplast ndhF–rpl32 intergenic spacer. Microsatellite data identify a total of 64 genotypes, despite this being a clonally propagated crop, and show three major dispersal hubs within Remote Oceania, centered on the islands of Fiji, Tonga, and Pitcairn. Of 64 genotypes identified, 55 correspond to genotypes associated to female-sexed plants that probably descend from plants introduced by the prehistoric Austronesian-speaking voyagers. The ratio of accessions to genotypes between herbarium and contemporary samples, suggests recent loss of genetic diversity. In addition to the chloroplast haplotypes described previously, we detected two new haplotypes within Remote Oceania both originating in Taiwan. This is the first study of a commensal species to show genetic structuring within Remote Oceania. In spite of the genetic bottleneck, the presence of only one sex, a timespan of less than 5000 years, and asexual propagation of this crop in Remote Oceania, we detect genetic diversity and regional structuring. These observations suggest specific migration routes between island groups within Remote Oceania. [ABSTRACT FROM AUTHOR]

Insley, S.J., Tauzer, L.M., Halliday, W.D., Illasiak, J., Green, R., Kudlak, A., and Kuptana, J. Ringed Seal Diet and Body Condition in the Amundsen Gulf Region, Eastern Beaufort Sea. Kaltenborn, [...]

Typically, the ash from incineration of paper sludge contains a high percentage of Ca in the form of anorthite (Ca[Al.sub.2][Si.sub.2] [O.sub.8]) and gehlenite ([Ca.sub.2][Al.sub.2]Si[O.sub.7]). The Ca in the sludge originates from calcite that is included in paper as fillers. We applied acid leaching with HCl on the ash to reduce its Ca content. Zeolite was then synthesized from the leached ash through reaction with 2.5 M NaOH solution at 80 [degrees]C for 24 hours. The fraction of Ca and Al extracted from the ash correlates with the pH of the leachant. We determined the leachant pH (after 24 hours of leaching) associated with the Ca:Al:Si ratio in the leached ash that provided optimal production of zeolites with high cation-exchange capacity. During acid leaching, gehlenite dissolved out at higher pH than anorthite. In the case of pH > 5. both gehlenite and anorthite remained m the ash, and hydroxysodalite and LTA (Linde Type A) were synthesized in the product. In the case of pH = 1-5 in the leachant, gehlenite dissolved out but anorthite remained in the ash, and LTA and Na-P1 (zeolite-P) were produced. In the case of pH < 1, both gehlenite and anorthite dissolved out, and only Na-P1 was produced. The cation-exchange capacities of the products that contained hydroxysodalite, LTA, and Na-P1 were approximately 130, 200, and 120 cmol/kg, respectively. We conclude that acid leaching of paper sludge ash controls which of the three zeolite phases form, and that LTA and Na-P1 exhibit a higher cation-exchange capacity than hydroxysodalite. The most efficient production of zeolites with high cation-exchange capacity (about 220 cmol/kg) is obtained after leaching the sludge ash in solutions of around pH = 3. At this low pH, gehlenite has already dissolved out of the sludge ash, half the Ca content of the ash has been leached out, Si has not yet been leached, but Al has begun to be leached. After ash zeolitization, LTA coexists with Na-P1 in the product.

Byline: F. Corfu (1) Author Affiliation: (1) Department of Geosciences, University of Oslo, PB 1047, Blindern, 0316, Oslo, Norway Article History: Registration Date: 27/10/2006 Received Date: 17/02/2005 Accepted Date: 24/10/2006 Online Date: 18/11/2006 Article note: Communicated by I. Parsons.

Unsuccessful oak (Quercus spp.) regeneration could result in losses of the rarer portions of the midwestern North American oak savanna region, including the tall grass oak savannas. We undertook this study to understand the effects of restoration on promoting growth of naturally occurring Q. alba seedlings in a degraded tall grass oak savanna in Iowa, USA. Initial restoration efforts, which involved mechanical removal of encroaching overstory trees, promoted positive increases in height and basal diameter of Q. alba seedlings in canopy gaps. Conversely, seedlings growing under Q. alba tree canopies in restoration areas and seedlings in control areas failed to display height and diameter increases. As seedlings were most abundant beneath Q. alba canopy trees, this created a dichotomy whereby seedling source (beneath canopies) and proper conditions for growth (in canopy gaps) were not one in the same. Although this restoration is still in its early stages, these results suggest that Q. alba regeneration may be successfully promoted at this site.

10-15 January 2021, Virtual Meeting The 2021 AMS Annual Meeting theme is 'Strengthening Engagement with Communities through our Science and Services'. For the full description of the theme, please visit [...]

Olnes, J., Citta, J.J., Quakenbush, L., George, C., Harwood, L., Lea, E., and Heide-Jorgensen, M.P. Use of the Alaskan Beaufort Sea by Bowhead Whales (Balaena mysticetus) Tagged with Satellite Transmitters, [...]

Rathwell, K.J. 'She is Transforming ...': Inuit Artworks Reflect a Cultural Response to Arctic Sea Ice and Climate Change. Melnikov, V.V. Observations of Annual Walrus (Odobenus rosmarus divergens) Migrations in [...]

R.M. QUIGLEY AWARD The R.M. Quigley Award is given out each year to the best paper published in Canadian Geotechnical Journal (CGJ) in the previous year. Bob Quigley was one [...]

Anders K. Angstrom was known primarily for his contributions to the field of atmospheric radiation. However, his scientific interests encompassed many diverse topics. This paper describes the contents of two early, remarkable, and, until recently, largely unknown papers by Angstrom on probability forecasting and the use/value of weather forecasts. These papers, entitled 'Sannolikhet och Praktisk Vaderleksprognos' ('Probability and Practical Weather Forecasting') and 'On the Effectivity of Weather Warnings,' were published in 1919 and 1922, respectively. Noteworthy features of these two papers include 1) a discussion of the sources of uncertainty in weather forecasting, 2) discourses on the problems of estimating probabilities by means of empirical relative frequencies and forecasters' subjective judgments, 3) the use of a Gaussian model to describe the accuracy of minimum temperature forecasts, 4) the identification of the ratio of the protection cost a to the 'risked value' if protective action is not taken b as a characteristic of users of forecasts, 5) analytical expressions for the economic value of weather warnings, 6) quantitative analysis of the problems faced by forecasters in deciding whether or not to issue weather warnings when they are uncertain about future weather conditions, and 7) arguments concerning the need to obtain estimates of the costs and losses that may be incurred by potential users in order to assess economic effectiveness. The contents of Angstrom's two papers are reviewed and summarized, making extensive use of quotations from the texts. An effort is made to place the papers and their contents in proper historical context. Two topics of current interest, namely, ensemble forecasting and the provision of specialized weather services, are discussed briefly in light of the results presented and issues raised in these papers.

Hydraulic conductivities of three compacted paper mill sludges were measured in various ways to assess their viability for use in barrier layers in landfill final covers. Compaction tests showed that the sludges have compaction curves similar to those for clays, albeit with lower maximum dry unit weights and higher optimum water contents. Hydraulic conductivities less than 1 x [10.sup.-9] m/s can be attained for these sludges at low effective stresses (20 kPa), hydraulic conductivities less than 1 x [10.sup.-9] m/s can be achieved at higher molding water contents. Field tests conducted on barrier layers constructed with two of the sludges showed that field hydraulic conductivities can be obtained that are similar to those measured on laboratory compacted specimens prepared at the same molding water content. Laboratory tests on large and small undisturbed specimens removed from the field showed that no scale dependence existed in the hydraulic conductivity of the field compacted sludge. Additional tests showed that freezing increased the hydraulic conductivity of two of the sludges, regardless of whether the sludges were permeated between freeze-thaw cycles or only after the last thaw. In contrast, for the third sludge, increases in hydraulic conductivity only occurred if the sludge was not permeated between freeze-thaw cycles. Significant shrinkage and cracking of the sludges occurred when they were dried, suggesting that barrier layers constructed with sludge should not be permitted to desiccate. Long-term tests showed that the hydraulic conductivity remains stable or decreases slowly if permeation is continued over an extended period of time.