bluuebunny/crossref_metadata_2025 huggingface dataset:
Librarian office hours in a family practice unit
Authors: Orchanian-Cheff Ani
Published: April 2011

Objective – To determine if the implementation of well-advertised "librarian office hours" in a busy clinical department of a teaching hospital would increase utilization of library services. Setting – The open-concept office of the Department of Family and Community Medicine at the Toronto Western Hospital site of the University Health Network. Program – As of June 2004, a librarian provided monthly office hours during the lunch hour in the Department of Family and Community Medicine. Staff were encouraged to e-mail any specific issues or questions to the librarian in advance of consultation, if possible, but all consultations were otherwise provided on a first-come, first-served basis. Results – In the 7-month period since the librarian office hours were initiated, 21 separate training sessions or consultations were provided to this department. This constitutes 15 sessions more than the number of sessions provided to this group in the same 7-month period in the previous year. Concurrently, the number of literature search requests made by this department has doubled compared with the same 7-month period in the previous year. Conclusion – User-centered information services for primary care professionals need to be mindful of clients' information-seeking preferences and lack of time. While providing librarian visits to individual hospital departments may not be the best use of a librarian's limited time and resources, in the drive to meet the unique needs of general practice, such an approach may be an advantageous way of librarians meeting client needs in the context of their own environment. Further examination of the benefits of approaches similar to this concept, for both librarians and hospital staff, is warranted.
Evaluating learning in library training workshops: using the retrospective pretest design
Authors: McDiarmid Mary , Binns Malcolm
Published: April 2011

The aim of this study was to assess the effectiveness of an evaluation instrument using the retrospective pretest design to measure changes in participants' behaviour after library training. This article focuses on the measurement component of training evaluation  the process of answering the question of how much change has occurred. Participants, who were from a large, public academic geriatric care centre in Toronto, included administrators, researchers, clinical and other staff, and university students doing field placements at the hospital. Participants attended one of four 1-hour sessions on the topic of Effectively Searching Google and Google Scholar that were held over a 3-month period. Sixty days post training, a self-administered retrospective pretest questionnaire, consisting of 10 searching behaviour statements developed using the learning objectives for the training session, was used to measure the impact of library training on participants' behaviour. Participants were asked to indicate their level of frequency of performing a searching behaviour described in the statement before and after training using a five-point, Likert-type scale ranging from 1, almost never; 2, seldom; 3, about half the time; 4, often; to 5, almost always. Summary baseline statistics are reported for respondents who never or rarely exhibited the behaviour prior to training. For the change measure, we report the simple percentage of respondents who improved. The findings of this study showed the potential of using the retrospective pretest to help librarians document the outcomes of library training. The benefits of gathering data using the retrospective pretest are discussed.
Consumer health information services in public libraries in Canada and the US
Authors: Murray Susan
Published: April 2011

In response to a growing demand from the public for health information resources, North American public libraries have provided varying levels of consumer health information (CHI) services since the 1970s. Due to the availability of funding in the US, many American public libraries have provided CHI services, although the majority of these have been as partnerships with health sciences libraries or via the “Go Local” programs. In Canada, where no specific funding has been available for CHI services, few public libraries have set up CHI services; health information has generally been provided by augmenting health collections or “virtually,” i.e., by providing links to recommended electronic resources via the library’s Web site.
Importance of human environmental exposure to hazardous air pollutants from gas flares
Authors: Kindzierski Warren B
Published: April 2011

Flaring is an accepted practice in the oil and gas industry to dispose of waste gases in Alberta. However, incomplete combustion of these gases produces a variety of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). Public health concerns about gas flaring have existed for a number of years. Several facts are notable in attempting to understand what importance VOCs and PAHs from flare gas emissions have in contributing to adverse health effects in humans. Most flare stacks are located in rural areas. Current time-activity studies of humans are lacking in that they have not emphasized characterization of time-activity behavior of rural populations, who would be most susceptible to exposure from these pollutants. Available time-activity studies of primarily urban populations indicate that people spend a majority of time indoors. Numerous VOCs and PAHs measured in gas flare emissions are already present indoors, originating from indoor sources, and almost always at higher levels than outdoors. As humans inhale a majority of air indoors, inhalation exposure would be influenced to a much greater extent from being indoors than outdoors in these instances. Human health risk assessment of hazardous air pollutants emitted from burning flares must take into account indoor and other background exposures to provide useful information for public health decision-makers.Key words: flaring, air pollutants, exposure, hazardous
Use and limitations of microbial bioassays for assessing copper bioavailability in the aquatic environment
Authors: Stauber J L , Davies C M
Published: April 2011

Although chemical measurement techniques and geochemical speciation modelling may detect and predict the different forms of copper in aquatic systems and hence provide some information about the likely toxicity of the water to aquatic organisms, they do not give direct quantitative data on adverse biological effects. Bioassays or toxicity tests are generic tests that use living organisms as indicators of contaminant bioavailability in aquatic systems. The microbial community, including protozoa, algae, bacteria, and fungi, provides a useful tool for directly assessing the hazard of copper in natural ecosystems. Most of our information on copper toxicity in aquatic systems comes from single-species tests using cultured organisms. However, whole community bioassays with natural phytoplankton and bacterial populations are finding increasing use. Although laboratory toxicity tests using ionic copper spiked into pristine seawater or synthetic softwater provide information on copper toxicity under controlled conditions, their usefulness for estimating bioavailable copper is limited in natural waters, where copper toxicity is ameliorated by complexation and adsorption. Careful selection of appropriately sensitive test species, bioassay endpoints, and test protocols is necessary to ensure the environmental relevance of the bioassays used. An understanding of metal speciation, metal-cell binding, mechanisms of toxicity, and limitations of the bioassays is required to understand copper bioavailability in natural waters and sediments. In this review, the use of bioassays with bacteria and microalgae for assessing copper bioavailability in marine and fresh waters and sediments is discussed, with particular emphasis on the limitations of current techniques. There is an urgent need for more environmentally relevant tests with sufficient sensitivity to detect bioavailable copper at concentrations close to water and sediment quality guideline values. Key words: bioassay, copper, metal, bioavailability, toxicity, bacteria, algae.
Canadian Wildlife Service's Herring Gull Monitoring Program: Importance to the development of environmental policy on organohalogens
Authors: Gilbertson M
Published: April 2011

The biological context for the selection of the herring gull (Larus argentatus), from a long list of candidate species, as an indicator of the restoration of Great Lakes water quality is further elaborated. Embryo mortality and deformities in herring gull chicks led to the hypothesis that the Lake Ontario population was exhibiting chick edema disease. Subsequent observation of the suite of lesions associated with chick edema disease in herring gull chicks led to the hypothesis that the Great Lakes were contaminated with polychlorinated dibenzo-p-dioxins. Forensic toxicology, as a collaboration of environmental chemistry, biology and pathology, could form a rational basis for policy decisions about remedial actions to restore extirpated fish and wildlife populations and to protect public health. Key words: indicator, restoration, diagnosis, forensic toxicology, public health.
Historical reconstruction of the earth's past atmospheric environment from Greenland and Antarctic snow and ice cores
Authors: Boutron Claude F.
Published: April 2011

During the past decades, the investigation of various elements, species, and isotopes in the frozen atmospheric archives stored in the Greenland and Antarctic ice caps for several hundred thousand years has provided a wealth of fascinating information on past and recent changes in the atmospheric environment of our planet. After a brief description of the Antarctic and Greenland ice caps, we give an overview of the procedures that are used in the field for collecting snow and ice from the surface down to great depths. We discuss the techniques used to date and analyse the samples. The main results obtained to date are then presented, with special emphasis on the very recent. The analysis of the snow and ice layers deposited during the past few centuries, especially since the Industrial Revolution, has allowed us to assess clearly the impact human activity has had on the atmosphere, for important constituents such as heavy metals, sulfur and nitrogen compounds, greenhouse gases, carbon and organic compounds, and artificial radionuclides. The analysis of ancient ice up to several hundred thousand years old has provided unique insight on the past natural changes that affected our atmosphere during glacial–interglacial transitions, especially the temperature, greenhouse gases, soil- and sea-derived aerosols, and heavy metals.Key words: Greenland, Antarctica, ice, global pollution, climate change, heavy metals.
Lake restoration by biomanipulation—a personal view
Authors: Shapiro Joseph
Published: April 2011

Restoration of over-fertilized, algae-laden lakes and reservoirs has generally been based on removal or reduction of phosphorus inputs and concentrations. However, this approach frequently is not feasible. An alternative is biomanipulation, in which the biota of the water body, particularly the fish population, is manipulated so as to reduce predation on small herbivorous zooplankters. This results in increases in body size of the zooplankters with consequent great increases in grazing rates on the algae. The process, though controversial, has worked in many lakes and offers promise to many more.Key words: biomanipulation, trophic cascade, lake restoration.
Common loon mortality in marine habitats
Authors: Spitzer Paul R.
Published: April 2011

The common loon remains remarkably anonymous and biologically little-known during its winter season. A major portion of the breeding population winters off coasts of the United States: Atlantic, Gulf, and Pacific. Adult common loons are flightless for a few weeks in midwinter during a simultaneous molt of their wing feathers. This apparently makes loons especially sensitive to environmental disturbance, because they are among the most commonly recorded dead and dying birds on coastal beaches from winter through spring. Loons' large size, slowness to die, and tendency to beach themselves as a last resort also render their mortality more visible. Contributing causes of mortality include storms, food limitation, entanglement in fishing nets, oil, and possibly, other toxic substances. Occasional, unpredictable die-offs of many hundreds (1993) or even thousands (1983) of emaciated loons have occurred in southeastern U.S. waters. Loons offer a prime opportunity for study of this unexplained marine mortality. In the 1980s, neurotoxic bioaccumulated mercury was hypothesized as a cause of mass mortality, but data on the mercury and selenium loading of loons and other long-lived marine carnivores, and on the marine mortality patterns of loons and other seabirds, indicate that mercury is not the cause. Algal neurotoxins in marine food chains have caused some seabird die-offs and are one useful hypothesis for future research. Interdisciplinary study of unusual seabird mortality events can provide a major paradigm for the study of marine environmental health.Key words: common loon, mortality, mercury, biotoxin, bioindicator, marine environment.
Environmental degradation and rehabilitation of the landscape around Sudbury, a major mining and smelting area
Authors: Winterhalder Keith
Published: April 2011

A century of sulphur dioxide fumigation, copper and nickel particulate deposition, fire, soil erosion, and enhanced frost action has created 10 000 ha of barren land and 36 000 ha of stunted, open birch–maple woodland in the Sudbury area. The primary factor limiting plant colonization is the acidic and aluminum-, copper-, and nickel-toxic properties of the soils, although certain plant species survive the challenges through genetically based metal tolerance. In revegetation programs, the soil can be detoxified sufficiently to initiate colonization by the surface application of ground limestone. The drought vulnerability of seedlings, resulting from soil toxicity limiting root growth, is exacerbated by enhanced frost action resulting from the lack of leaf litter. Manual surface application of ground limestone, with or without an accompanying fertilizer and (or) grass–legume seed application, leads to immediate colonization by woody species including birch, aspen, and willows, and more than 3000 ha have been treated in this way by the Regional Municipality of Sudbury since 1978. Native coniferous species have also been planted in groups to form a seed source for future colonization. Most barren soils contain a substantial reservoir of phosphorus and nitrogen in the form of residual organic matter, but both rhizobial and actinorhizal species play an important role in dynamics, and the role of mycorrhizae is probably critical. The seed availability factor is rarely limiting; while the seed bank is small, in most sites the seed rain of light, wind-dispersed seeds is adequate to colonize soil detoxified by liming.Key words: Sudbury, pollution, revegetation, copper, nickel, toxicity.
Bioavailability and toxicokinetics of hydrophobic aromatic compounds in benthic and terrestrial invertebrates
Authors: Belfroid A. C. , Sijm D. T. H. M. , Gestel C. A. M. Van
Published: April 2011

Uptake and accumulation of persistent hydrophobic chemicals by benthic and terrestrial invertebrates in water, sediment, and soil depends on the hydrophobicity of the compound (log Kow) and the lipid content of the organism. Several methods exist to determine the route of uptake. Their advantages and drawbacks are discussed. The route of uptake of hydrophobic contaminants is mainly via interstitial water, but for compounds with log Kow > 5 uptake from soil and sediment particles becomes important. In the presence of sediment or soil, the bulk of hydrophobic contaminants is sorbed to sediment/soil particles. Accumulation is, therefore, also controlled by sorption-related factors, such as the organic matter content and composition of sediment/soil, the presence of oil, particle size distribution, and the residence time of the contaminant. Other factors may be clay content and the presence of metals. It is shown that organic matter is the most important factor controlling accumulation in benthic and terrestrial organisms, while residence time of the contaminant and composition of organic matter seem to be of next importance. Also animal behaviour influences uptake and accumulation, such as size of the organism, avoidance of highly contaminated sites, burrowing behaviour, biotransformation, density of the organism population, and bioturbation. The influence of above mentioned factors on the equilibrium partitioning theory and related models for estimating accumulation levels was examined. The omittance of uptake from soil and sediment particles, the normalization on lipid content irrespective of other animal characteristics, biotransformation, organic matter composition, residence time of the contaminant, and the presence of oil are major factors interfering. As a result, a discrepancy between equilibrium partitioning theory estimated and actual accumulation levels of persistent hydrophobic compounds in benthic and terrestrial organisms exist.Key words: hydrophobic chemicals, accumulation, bioavailability, terrestrial organisms, benthic organisms, equilibrium partitioning theory.
Atmospheric emissions and depositions of cadmium, lead, and zinc in Europe during the period 1955–1987
Authors: Olendrzyński Krzysztof , Anderberg Stefan , Stigliani William , Bartnicki Jerzy , Pacyna Józef
Published: April 2011

This paper presents a preliminary estimate of atmospheric emissions of cadmium, lead, and zinc in Europe during the period 1955–1987. The emission data were used as input to the atmospheric transport model TRACE (trace toxic air concentrations in Europe) of the International Institute for Applied Systems Analysis, to compute cumulative deposition loads of heavy metals onto European soils during the investigated time period. The maxima of cumulative depositions computed with the TRACE model over the entire period were approximately 60 mg/m2 for cadmium, 1450 mg/m2 for lead, and 2600 mg/m2 in the case of zinc. The results presented should be considered first-order approximations. Major uncertainties embedded in such calculations are discussed. Heavy metals enter the soils from atmospheric load and with the application of fertilizers and sewage sludge. Once in the soil the metals can be mobilized, leading to plant and groundwater contamination. This threat is particularly valid for heavily polluted regions in Central Europe. The results of this study can be applied in assessing environmental and health effects of heavy metals and, therefore, are important for scientists as well as policy makers.Key words: trace elements, heavy metals, historical emission, cumulative deposition.
Large-scale impacts of hydroelectric development
Authors: Rosenberg D M , Berkes F , Bodaly R A , Hecky R E , Kelly C A , Rudd J WM
Published: April 2011

The substantial size of some hydroelectric projects and the extensive total surface area covered by reservoirs globally require that research determining the impacts of these developments be done at ever-increasing spatial and temporal scales. As a consequence of this research, new views are emerging about the spatial extent and longevity of the environmental and social impacts of such developments. New findings challenge the notion of hydroelectric development as a benign alternative to other forms of power generation. This review examines the intertwined environmental and social effects of methylmercury bioaccumulation in the food web, emission of greenhouse gases from reservoirs, downstream effects of altered flows, and impacts on biodiversity, each of which operates at its own unique spatial and temporal scales. Methylmercury bioaccumulation occurs at the smallest spatial and temporal scales of the four impacts reviewed, whereas downstream effects usually occur at the largest scales. Greenhouse gas emissions, the newest surprise connected with large-scale hydroelectric development, are relatively short term but eventually may have important global-scale consequences. Limitation of biodiversity by hydroelectric development usually occurs at intermediate spatial and temporal scales. Knowledge developed from working at expanded spatial and temporal scales should be an important part of future decision making for large-scale hydroelectric development.
The importance of buried seeds and vegetative propagation in the development of postfire plant communities
Authors: Whittle C A , Duchesne L C , Needham T
Published: April 2011

Understorey vegetation in boreal and subboreal ecosystems is critical to ecosystem dynamics by contributing to nutrient cycling, soil aggregation, and soil fertility. As well, it provides habitat for animals and microorganisms and creates suitable microsites for the regeneration of tree species. Within a context of holistic or ecological management, it is important to understand the dynamics of understorey vegetation after disturbance. However, there is a lack of information on the effect of disturbance on plant diversity. Regeneration of plant communities in postdisturbance boreal and subboreal ecosystems is discussed with particular reference to (i) current knowledge of buried seeds (soil seed banks) and vegetative propagation, and (ii) the importance of the fire regime on plant regeneration. In future, research should emphasize new methods to measure fire behaviour to predict the effect of fire on plant diversity. As well, a good understanding of plant succession should help the implementation of ecological management of industrial forests.
The radiological consequences of the Chernobyl accident
Authors: Voice Eric
Published: April 2011

The human health consequences of the Chernobyl accident in 1986 have been the subject of a great many studies. Many of the findings and opinions were brought together at a major international conference held in Minsk in 1996. The overall findings from this workshop are discussed with particular focus on thyroid cancers and exposures to iodine-131.
Review of status and threats to river cetaceans and recommendations for their conservation
Authors: Smith Alison M , Smith Brian D
Published: April 2011

River dolphins are among the world's most seriously endangered species, and the baiji (Lipotes vexillifer), endemic to the Yangtze River, China, is likely to become extinct in the near future. Here we review the status of the obligate river dolphins (baiji, bhulan, Platanista minor, susu, Platanista gangetica, and boto, Inia geoffrensis), discuss the threats they face, and present recommendations for their conservation. River dolphins are particularly vulnerable to the activities of humans because of their restricted habitat. Threats vary geographically in their importance, but generally include accidental killing during fishing operations, depletion of prey from over-exploitation, and habitat loss and population fragmentation from water development. Deliberate killing for dolphin products also threatens the animals in some areas. Recommendations include (among others) the following: (i) establishing meaningful protected areas, (ii) raising public awareness on the ecological and cultural value of river dolphins, (iii) training local workers in conservation techniques, (iv) managing fisheries to reduce accidental killing and ensure the sustainability of prey, and (v) adopting conservation strategies that incorporate the ecological integrity of riverine environments.Key words: River dolphins, Platanista, Lipotes, Inia, Orcaella, Neophocaena, Sotalia, water development, river ecosystems.
The role of environmental science and politics in identifying persistent organic pollutants for international regulatory actions
Authors: Selin Henrik , Hjelm Olof
Published: April 2011

The aim of the present study is to describe and analyze the character of the interplay between environmental science and policy-making in the process of identifying persistent organic pollutants (POPs) for initial inclusion in the POPs Protocol under the Convention on Long-Range Transboundary Air Pollution (CLRTAP). The objective of the CLRTAP POPs Protocol is to control, reduce, or eliminate discharges, emissions, and losses of organic compounds that are toxic, persistent, bioaccumulative, and prone to long-range atmospheric transport and deposition within the CLRTAP region, which covers North America and Europe, including the European region of the former Soviet Union. The empirical materials used were documents underlying decisions and personal observations at seven CLRTAP POPs meetings. In order to describe and analyze the role of environmental science and politics in identifying an initial list of regulated substances, we have chronologically recapitulated the CLRTAP POPs process leading up to the adoption of the POPs Protocol. Our work was guided by two research questions: What was the strength of the interplay and were there any key events of interplay? Our analysis revealed a strong interplay between environmental science and policy-making throughout the process, mutually (but not always equally) affecting each other. We have identified four events of interplay that were of significance for the final outcome: the initial problem identification, the selection of CLRTAP as a forum for cooperative actions, the screening of possible protocol POPs, and finally, the concluding protocol negotiations.Key words: Convention on Long-Range Transboundary Air Pollution, negotiations, persistent organic pollutants, risk assessment.
Analyse de la variabilité morphologique chez huit populations spontanées dePistacia atlanticaen Algérie
Authors: Belhadj Safia , Derridj Arezki , Auda Yves , Gers Charles , Gauquelin Thierry
Published: April 2011

To study the morphological variability within and among Pistacia atlantica Desf. populations, a comparative analysis was undertaken in eight wild populations grown under different climatic conditions in Algeria. This study addresses the morpho-biometrical aspect of the leaves and the fruits, as well as the micromorphological aspect of leaves. ANOVA as well as mean comparison of the morphological traits revealed a significant diversity within and among the populations. Furthermore, in the multivariate analysis, the populations were separated into four different groups through the discriminating variables: leaf and leaflet dimensions, number of pairs of leaflets, leaf wings, leaf smell and colour, terminal leaflet size and apex, and finally fruit colour and shape. These results showed the originality of the Algerian populations as compared with those commonly described for this species in the literature, in particular by the occurrence of wax on the leaves. The morphological variability exhibited by the Algerian populations of P. atlantica may be interpreted as relevant to the ecological plasticity and the physiological mechanisms discussed in this article.
Pollen limitation and cleistogamy in subalpine Viola praemorsa
Authors: Forrest Jessica , Thomson James D.
Published: April 2011

Early-flowering species may be especially susceptible to occasional pollen limitation and, therefore, may benefit from a mixed-mating strategy that provides reproductive assurance. We studied cleistogamous (CL) and chasmogamous (CH) fruit set of spring-flowering Viola praemorsa Dougl. ex Lindl. along an elevational gradient in the Rocky Mountains, testing whether pollen limitation or allocation to CL reproduction covaried with timing of flowering onset, within and across sites. Contrary to predictions, we found no pollen limitation of reproduction at any site, and variation among sites in the pattern of allocation to cleistogamy was not related to growing season length. Differences in reproductive strategy between early- and late-flowering plants within sites were attributable to differences in plant size, with relative allocation to cleistogamy increasing with size. This pattern has been found in some other cleistogamous species, and may indicate a cost of large CH floral displays, perhaps associated with geitonogamy or herbivory. We found no experimental evidence for resource reallocation in response to CH reproductive output, although a weak negative relationship between CH and CL fruit set across a larger sample of unmanipulated plants suggests such a trade-off. The significance of cleistogamy may be clarified by studying how pollinator visitation, self-pollination, and herbivore damage vary temporally and with floral display size.
Field-based effects of allelopathy in invaded tallgrass prairie
Authors: Harnden Jesse , MacDougall Andrew S. , Sikes Benjamin A.
Published: April 2011

Allelopathic phytochemicals have been linked to invasion success, but their role in the invasion process remains unclear. Toxicity effects demonstrated with lab bioassays may be neutralized in soils, and their role in population expansion can be intertwined with nonallelopathic processes that also influence dispersal and establishment. Here, we use greenhouse experiments to test the soil-based impacts of invasive fine fescue ( Festuca rubra L.) on recruitment in tallgrass prairie. Fescue roots release the growth inhibitor m-tyrosine. Using root washes and fescue-conditioned soils to mimic field potency, we determined allelopathic impacts on recruitment, including intraspecific limitation. We also tested whether nonallelopathic factors (propagule pressure, disturbance, and fertility) influence invasion into constructed fescue and prairie mesocosms, and whether root washes inhibit arbuscular mycorrhizal (AM) fungi. We observed significant negative effects of fescue soils and root washes on germination and seedling survival, including on fescue itself. Mesocosm invasion, however, was determined more by nonallelopathic mechanisms (propagule pressure and rapid growth). In prairie mesocosms, fescue invasion was higher than its own understory, with no effects of disturbance or fertility. Tallgrass species had difficulty establishing in all environments, regardless of propagule pressure. Impacts on AM fungal hyphal length and spore production were insignificant. Our results suggest that nonallelopathic traits may be sufficient to explain fescue invasion, with allelopathy likely emerging as a final "coup de grâce" for recruiting native grasses once dominance has been attained. Allelopathic species, including fine fescue, may thus not necessarily be invasive unless nonallelopathic traits facilitate establishment prior to the accumulation of soil-based toxins.
Post-transplant reactions of mycorrhizal and mycorrhiza-free seedlings of Leucaena leucocephala to pH changes in an Oxisol and Ultisol of Hawaii
Authors: Habte M. , Diarra G. , Scowcroft P.G.
Published: April 2011

The extent to which pretransplant colonization of seedlings with the arbuscular mycorrhizal fungus (AMF) Glomus aggregatum Schenck and Smith emend. Koske could enhance the post-transplant growth of two cultivars of Leucaena leucocephala (Lam.) de Wit (cv. K-8 and cv. K-636) in Al- and Mn-rich acid soils was evaluated in a greenhouse. Arbuscular mycorrhizal colonization measured at the end of the experiment was significantly stimulated by inoculation in both cultivars at all pH levels tested, although colonization was most stimulated if cv. K-8 was grown in the Al-rich soil at the lowest pH. Symbiotic effectiveness measured as P content of Leucaena pinnules was significantly suppressed in both cultivars if they were grown at the lowest pH. Symbiotic effectiveness measured as pinnule P content and shoot biomass yield was enhanced in both cultivars by liming. The trends in effectiveness were similar in both cultivars, but cultivar effect was significant in the Mn-rich Oxisol (Wahaiawa soil) but not in the Al-rich Ultisol (Leilehua soil). The tolerance of the cultivars to acid soil toxicity in the Wahiawa soil varied with the pretransplant mycorrhizal status of their seedlings. The effect of pretransplant colonization of seedlings was to eliminate the differences in the tolerance of the cultivars to acid soil toxicity. Our data suggest that AMF could offset some of the growth reduction associated with soil acidity and that host genotype could play a role in this regard.
THE HYDRATION OF THE ALUMINATES OF CALCIUM: I. A NEW CRYSTALLINE FORM OF HYDRATED TRICALCIUM ALUMINATE
Authors: Thorvaldson Thorbergur , Grace Norman S.
Published: April 2011

In an investigation of the resistance of Portland cement to sulphate action a new form of hydrated tricalcium aluminate, with six molecules of water, was prepared by treating pure tricalcium aluminate with steam under pressure and drying the product over quicklime. This hydrate is crystalline and isotropic. It is stable at 100 deg. C., but at 275–300 deg. C. it gives up three-quarters of its water, forming a stable 1.5-hydrate. Some water is retained up to 1000 deg. C. Before the last of the water is expelled decomposition of the aluminate takes place. Recombination occurs at 1000–1100 deg. C.
VACCINATION AGAINST TUBERCULOSIS WITH BACILLUS CALMETTE-GUERIN
Authors: Rankin A. C.
Published: April 2011

This paper covers work on B.C.G. vaccine carried on in Alberta over a period of approximately four years, during which time some 250 calves were made the subject of experiments. The vaccine was found to be entirely harmless, vaccinated calves developing normally and showing at autopsy no tuberculous lesions. Vaccinated animals in most cases reacted subsequently to the tuberculin test. Calves vaccinated with B.C.G. and immediately exposed to infection showed moderately increased resistance to tuberculosis over unvaccinated controls. Calves vaccinated with B.C.G. and subsequently kept under sanitary conditions for a period, in order to permit resistance to develop before exposure to infection, showed 80 per cent immunity as compared with 14 per cent for the controls. The tuberculous lesions found in vaccinated calves were in general much less pronounced as well as less numerous than those in unvaccinated animals. (F.E.L.)
THE DISCOLORATION OF HALIBUT
Authors: Harrison F. C.
Published: April 2011

The greenish-yellow discoloration of the ventral side of Hippoglossus hippoglossus (Linn.) is described. This discoloration is often accompanied by softness of the flesh, which greatly reduces the value of the fish. The color-producing organism was isolated and identified as Pseudomonas fluorescens; its characteristics are given. Examination of materials from which the halibut might be infected revealed that the ultimate source of the organism was the fresh-water ice in which the fish were packed after being caught. Some sixteen other organisms, isolated from freshly caught living halibut and from sea water, are fully described.
STUDIES ON THE ACTION OF SULPHATES ON PORTLAND CEMENT: III. THE EFFECT OF THE ADDITION OF SILICA GEL TO PORTLAND CEMENT MORTARS ON THEIR RESISTANCE TO SULPHATE ACTION
Authors: Thorvaldson T. , Vigfusson V. A. , Wolochow D.
Published: April 2011

The effect of substituting silica gel for a portion of the Portland cement in standard and graded-sand mortars on the expansion and loss in strength of the mortars in sulphate solutions was determined. Portland cement silica gel sand mortars were cured in steam at 100 °C. and the effect on their sulphate resistance measured; the behavior of lime-silica gel sand mortar in solutions of sodium and magnesium sulphate was also studied. It was found that the addition of silica gel to the mortar, very effective in preventing expansion and maintaining the tensile strength of the mortar in solutions of sodium, and calcium sulphate, was not so effective in solutions of magnesium sulphate. Steam-cured mortars containing silica gel to the extent of 20% of the cement present showed a slightly greater resistance to the action of solutions of sodium and calcium sulphates, but less resistance in solutions of magnesium sulphate, than similar steam-cured mortars containing no silica gel. Lime-silica gel sand mortars behaved very similarly in sulphate solutions as Portland cement mortars containing silica gel. The possible causes of the effects produced by the addition of silica gel to Portland cement mortars are considered, and several explanations discussed.
DURATION OF META-STABLE STATES
Authors: Anderson J. M.
Published: April 2011

The half-value time of absorption from meta-stable electronic atomic states is calculated on the hypothesis that the whole decay is due to collision phenomena. Definite assumptions, which include the atomic energy level scheme, are made as to the efficiency of collisions and the interaction of two meta-stable states in these processes. The assumption adopted as the only one producing an approximation to experimental facts shows that the probability of an exchange is dependent on the absolute value of the energy difference between the states concerned. The results calculated from the final formula, for helium, neon and argon at normal and very low temperatures depend on one arbitrary constant, which is the same for all states and gases considered, and show fair agreement with any experimental values so far published. An estimate is made of the energy tolerance of a quantum transition.
THE THEORY OF THE ZONE PLATE DERIVED FROM VOIGT'S INTEGRAL
Authors: Lane C. T.
Published: April 2011

The properties of the zone plate are worked out theoretically, using the method developed by Voigt for diffraction problems. The case treated is the one for which the plate is illuminated by monochromatic plane waves at normal incidence. The various approximations made are clearly indicated and the results obtained are compared with experimental data.
EQUILIBRIA IN SULPHUR DIOXIDE SOLUTIONS
Authors: Campbell W. Boyd , Maass O.
Published: April 2011

The investigation described deals with the equilibria existing in a water solution of sulphur dioxide. The vapor pressures and conductivities of solutions of sulphur dioxide were measured over the temperature range 23° to 135 °C. at various concentrations up to 8%. The densities of the aqueous solutions up to 15% were also measured. A discussion of the various equilibria in the light of these data leads to the conclusion that sulphurous acid is one of considerable strength, its apparent weakness being due to the small amount of H2SO3 actually present. With rise in temperature the free sulphur dioxide increases and the hydrogen-ion concentration of the sulphite liquor used in current practice is so low that it seems highly improbable that the cooking reaction is due essentially to this factor. Apart from the bearing this work may have on the theory of sulphite cooking and the theory of the equilibria existing in the SO2−H2O system, it fills a considerable gap in the data regarding sulphur dioxide.
A COMPARISON OF THE ACTION OF B.WELCHII TOXIN WITH OTHER HAEMOTOXINS ON HUMAN AND RABBIT RED CELLS IN VITRO
Authors: Orr J. H. , Campbell W. A. , Reed G. B.
Published: April 2011

The effect of various representative hæmotoxins on human and rabbit red blood cells in vitro was studied. It was found that as a result of the action of B. welchii toxins produced from a variety of strains of the organism a definite anisocytosis was produced and that the change in size of the cells followed a regular sequence. The first change to be noted was a development of cells having an average diameter less than the normal (microcyte stage). Further action of the toxin resulted in the replacement of these microcytes by cells having an average diameter greater than the normal (macrocyte stage). Following this macrocyte stage it was found that there was a return of the cells to a diameter very closely approximating the normal. This change in the size of the cells did not appear as a result of the action of any of the other hæmotoxins worked with viz., B. tetani, V. septique, Strepto. scarlatinœ, Staph. aureus.
CHROMOSOME CONDITIONS IN THE SECOND AND THIRD GENERATIONS OF PENTAPLOID WHEAT HYBRIDS
Authors: Jenkins J. A. , Thompson W. P.
Published: April 2011

The numbers and mating capabilities of the chromosomes were determined in a good many F2plants and their offspring in two crosses between common (42-chromosome) wheat and emmer (28-chromosome) types. In general the results confirmed those of Kihara and supported his conclusions. Chromosome numbers were much nearer those of the parental types than was to be expected if all germ cells were capable of functioning and all zygotes of developing. A large number of expected chromosome types did not appear at all. A high percentage of F2had only 14 bivalent chromosomes and zero to seven univalents. These tended to revert rapidly to the 14-bivalent condition of emmers. F3in this group did not have more than 14 bivalents nor more univalents than their F2parents. A chromosome formula for all of the group of F2with more than 14 bivalents may be written (14+x) bivalents +(7−x) univalents. Thesetended to revert to the 21-bivalent condition of common wheat. F3in this group did not have fewer bivalents nor more univalents than their F2parents. Occasional plants were exceptions to these rules.
STUDIES ON "BROWNING" ROOT ROT OF CEREALS: I. THE ASSOCIATION OF LAGENA RADICICOLA N.GEN.; N.SP., WITH ROOT INJURY OF WHEAT
Authors: Vanterpool T. C. , Ledingham G. A.
Published: April 2011

A specific root rot of wheat and other cereals is described which is widespread over Saskatchewan, and occasions severe losses in some seasons. In early June, the outer leaves of the young plants become discolored, the number of tillers is reduced, growth delayed, and the yield considerably lessened. One of the chief diagnostic features is the presence of lesioned root tips containing oospores of the Pythium type. Although the disease is worst in a cool, wet spring, followed by warm, dry weather, the plants recover markedly when the remainder of the growing season is favorable. In preliminary work, "isolation strains" of various fungi from lesioned roots of field material collected in mid-summer failed to produce the disease under greenhouse methods of inoculation.A fungus belonging to the lower Phycomycetes, hitherto not described, was found associated with rootlet injury of wheat, barley, rye and maize seedlings grown in Regina clay soil from infested fields of southern Saskatchewan. Its life-history, morphology and physiological characters are given in detail; it is believed to be an obligate parasite which, under conditions favorable to its development, is capable of causing definite injury to wheat. It is not considered one of the major causes of browning root rot, but in the section where it is common it is likely one of the contributing causes in some seasons. It is regarded as belonging to the Ancylistaceæ, close to the genus Lagenidium, but the erection of a new genus Lagena is recommended. The binomial Lagena radicicola has been assigned to the fungus.More recently several "isolation strains" of Pythiaceous fungi have been secured from infected roots of wheat seedlings grown in soil collected from browning root-rot fields. A few of these in pot experiments in the greenhouse are shown to be definitely parasitic on the roots of wheat plants. There is some evidence that the particular root-rot concerned belongs to the Pythium root-rot complex type.
INVESTIGATION OF THE REACTION BETWEEN HYDROGEN CHLORIDE AND THE THREE BUTYLENES
Authors: Coffin C. C. , Sutherland H. S. , Maass O.
Published: April 2011

The reactions between α, β and γ-butylenes and hydrogen chloride are investigated. It is shown that, of the butyl chlorides produced, only the secondary chloride is formed in the reactions with α- and β-compounds, and only the tertiary chloride in the reaction with the γ-compound. In the case of the first two reactions (with α- and β-compounds) it is shown that a secondary product (an octyl chloride) is formed. Its possible structure, 3-methyl-4-chlormethyl hexane for the reaction with the α-compound and 2-chlor-3, 4-dimethyl hexane for the reaction with the β-compound is indicated, and it is shown that these decompose into an octylene and hydrogen chloride. The mechanism of the various reactions and its relation to the rates of reaction is suggested.
THE RELATIONSHIP BETWEEN MORPHOLOGIC CHARACTERS AND RUST RESISTANCE IN A CROSS BETWEEN EMMER, (TRITICUM DICOCCUM) AND COMMON WHEAT, (TRITICUM VULGARE)
Authors: Harrington J. B.
Published: April 2011

A study of morphologic character in relation to field resistance to black stem rust of wheat (Puccinia graminis tritici, Erikss. & Henn) was made on the cross Vernal (Triticum dicoccum, Schubl.) × Marquis (T. vulgare, Host.). Fifteen morphologic characters were used including spike form, spike compactness, stem hollowness, rachis articulation, rachis width, spikelet adherence, glume adherence, keel sharpness and seed character, all of which are of species differentiating importance. A random group of 276 F2plants showed no strong or moderately strong correlations between rust reaction and other characters: the most significant correlation coefficients ranged from.13 to.27. Between any two morphologic characters no strong relationships were found, the highest correlation coefficient obtained being.37. In the entire F2population of 21,480 plants there were 232 vulgare-like hybrids showing the high rust resistance of Vernal, although Marquis had a fairly uniform infection of moderate severity. All of these hybrids proved, upon laboratory examination, to be of vulgare or near-vulgare type in nearly all characters especially the economically important characters spike form, rachis articulation, spikelet adherence and glume adherence. This study, therefore, demonstrates that high rust resistance can be transferred from dicoccum to a vulgare-type wheat without great difficulty. It is concluded that the attainment of desirable combinations of emmer rust resistance with important morphologic characters of vulgare depends primarily upon having a population of many thousands of individuals from which to select.
THE EFFECT OF THE ULTRA-VIOLET COMPONENT OF THE SUN'S RADIATION UPON SOME AQUATIC ORGANISMS
Authors: Klugh A. Brooker
Published: April 2011

Specimens of three species of fresh-water entomostracans—Daphnia pulex, Daphnia magna and Cypris reticulate—were each exposed to sunlight which had passed through filters which transmitted different regions of the solar spectrum. One filter ("Total") transmitted both visible and ultra-violet radiation, a second ("Novial") transmitted the visible only and a third ("U.V.") transmitted only the ultra-violet. By prolonged exposure the animals were killed under the Total and U.V. filters, while under the Novial they lived indefinitely. The chief point of interest lies in the comparison of the results obtained with these entomostracans which live in shallow pools with the results of previous experiments (2) on three marine entomostracans which remain at a considerable depth in the sea when the illumination is at all intense; the comparison shows that the former have a far greater resistance to the lethal effects of the sun's ultraviolet radiation. Developing embryos of the squid, Loligo pealii, were experimented upon in a similar manner; these embryos, which are enclosed in a gelatinous matrix attached to large algae in the intertidal zone, and, at low tide, are exposed to full sunlight, were extremely resistant to ultra-violet radiation.