bluuebunny/crossref_metadata_2025_split huggingface dataset:
The changing face of the Ethiopian rift lakes and their environs: call of the time
Authors: Ayenew Tenalem , Legesse Dagnachew 
Published: August 2007

AbstractThe Ethiopian rift is characterized by many perennial rivers, and a chain of lakes that vary in size, and hydrological and hydrogeological settings. The water resources of the Rift lakes are one of the focal points for large‐scale development in Ethiopia over the last few decades. Some of the lakes and their influent rivers are used for irrigation, soda abstraction, fish farming and recreation, and also support a wide variety of endemic birds and wild animals. Ethiopia's major mechanized irrigation farms and commercial fishery are confined within the Rift region. A few of the lakes have shrunk in surface area because of excessive water abstractions, while others have expanded because of increased surface run‐off and groundwater inflows from percolated irrigation water. Excessive land degradation, deforestation and over‐irrigation have changed the hydrological setting of a few Rift lakes. Human activities, in combination with changes in climate and geology, have influenced the hydrological setting and the water quality of the lakes, with the salinity and major ion composition dramatically changed in some of them. This study tries to address the challenges associated with development of these surface‐water resources, focusing on environmental problems arising over the past few decades on three lakes (Abiyata, Beseka and Ziway) situated along the tectonically active Rift floor. The methods utilized in this study include field hydrological and hydrogeological mapping, supported by aerial photographs and satellite imagery interpretations, as well as hydrometeorological and hydrochemical data analysis, and catchment hydrological modeling. A converging‐evidence approach was adapted to reconstruct the temporal and spatial variations of the lake water levels and surface areas. The study results revealed that the major changes in the Rift Valley are related primarily to recent improper use of water from the large rivers draining the Rift Valley floor and the lake catchments, and from direct lake water abstractions aggravated intermittently by climatic and land use changes. These changes represent grave environmental consequences on the fragile Rift ecosystem that demands urgent intervention in the context of an integrated, basin‐wide water management approach. This study emphasizes lake water level changes and human influences on these changes. It also assesses human interactions and water quality changes, including land use changes and environmental repercussions on the lakes, as well as providing recommendations on how these issues should be addressed.
Factors influencing primary productivity in Panshet and Ujjani Reservoirs, India
Authors: Vaidya Shanti , Dhilipkumar Radhakrishnan , Swain Kishore Kumar , Prabhakar Vuppati Mark , Basu Apurba Kumar 
Published: August 2007

AbstractNitrogen and phosphorus concentrations and their ratios are important factors influencing the primary productivity of a reservoir. Based on analyses of Panshet and Ujjani Reservoirs in Maharashtra, India, it was observed that, in addition to their nitrogen and phosphorus concentrations and ratios and other chemical constituents, physiographical factors such as geography, catchment land use, water basin morphology, bathymetry and changing water levels or flushing rates also influenced the productivity of these two reservoirs.
Eutrophication, phytoplankton dynamics and nutrient removal in two man‐made urban lakes (Palácio de Cristal and Serralves), Porto, Portugal
Authors: Xavier L. , Vale M. , Vasconcelos V. M. 
Published: August 2007

AbstractUrban lakes are prone to eutrophication because of a number of factors, including a high water residence time (slow flushing rate), and high nutrient loads from artificial feeding of waterfowl and fish by visitors and from waterfowl faeces, falling leaves and nutrient run‐off from adjacent areas. This study focuses on the ecology of two similar‐sized urban lakes in Porto, Portugal, that exhibit some differing characteristics conducive to different trophic states and nutrient removal efficiencies. Although similar in many aspects, the two reservoirs developed quite diverse phytoplankton communities. The higher nitrogen load to Palácio de Cristal Lake could be the result of the higher concentration in its underground influent stream, while a less‐oxidized nitrogen form (ammonia) is higher in Serralves Lake. Nitrate concentrations are higher in Palácio de Cristal Lake than in Serralves as a result mainly of high nitrate loads (maximum values above 80 mg L−1) in its influent stream. Interestingly, however, its nitrate removal efficiency is greater than for Serralves Lake. Cyanobacteria are the dominal phytoplankton In both lakes throughout the year. However, only one genus of this group (Pseudoanabaena mucicola) was the dominant phytoplankton in Palácio de Cristal Lake, while five Cyanobacteria species co‐dominated in Serralves lake. Regular monitoring of Cyanobacteria and their toxins in urban recreation lakes is advised.
Management of metastatic carcinoma of the uveal tract: an evidence‐based analysis
Authors: Kanthan Gowri L , Jayamohan Jay , Yip Desmond , Conway R Max 
Published: August 2007

AbstractUveal metastasis from carcinoma is the most common cause of ocular malignancy in adults and represents an increasing problem in the context of an ageing population and enhanced survival of stage IV cancer patients. The reported prevalence of clinically evident uveal metastases in carcinoma patients ranges from 2% to 9%, with breast and lung cancer together accounting for between 71% and 92% of cases. Most patients (66–97%) have a known history of cancer and, although the majority have metastatic lesions elsewhere, up to 33% may present with an isolated ocular metastasis. These lesions may progress rapidly and are potentially sight‐threatening. Early diagnosis and appropriate timely treatment are therefore of paramount importance to maintain patients' quality of life. The diagnosis is usually clinical and detailed descriptions of symptomatology and physical characteristics are provided. In 21–50% of patients, involvement is bilateral. External beam radiotherapy (EBRT), chemotherapy, hormone and biological therapies, brachytherapy, transpupillary thermotherapy, laser photocoagulation/photodynamic therapy and enucleation are therapeutic modalities described in the literature for the management of uveal metastases. The strongest evidence favours timely EBRT for the management of sight‐threatening uveal metastases. The published evidence supporting EBRT for sight‐threatening uveal metastases was given a grade B (strong support for recommendation). Newer alternative therapies are emerging and may have a role in selected patients; however, there are unfortunately few large studies examining such treatments for carcinoma metastatic to the eye. The role of these modalities will be further clarified with the results of larger comparative trials.
Peripheral ulcerative keratitis due to a ‘long lost’ hard contact lens
Authors: Bhatt Priya R , Lam Fook C , Roberts Fiona , Ramaesh Kanna 
Published: August 2007

AbstractPeripheral ulcerative keratitis (PUK) is a disorder consisting of a crescent‐shaped destructive inflammation of the perilimbal corneal stroma. PUK can occur in a variety of ocular and systemic conditions including infections, lid abnormalities, dermatological disorders and connective tissue disorders. We present a case of PUK associated with a hard contact lens (CL) retained in the superior fornix for over 16 years. After removal of the embedded CL, a superior forniceal conjunctival pedicle graft was performed to prevent corneal perforation. The patient was managed postoperatively with a combination of topical steroids and antibiotics. The use of systemic immunosuppressive therapy was not necessary. Micro‐trauma and micro‐keratitis may have occurred as a result of the mechanical effect of the CL but if this was the sole mechanism, one would expect presentation at a much earlier date. We discuss the pathogenetic mechanisms which may have contributed to the development of this ulceration. This report highlights the importance of lid eversion when examining patients with anterior segment pathology.
Influence of unilateral disc displacement on the stress response of the temporomandibular joint discs during opening and mastication
Authors: Pérez del Palomar A. , Doblaré M. 
Published: August 2007

AbstractThe temporomandibular joint plays a crucial role in human mastication acting as a guide of jaw movements. During these movements, the joint is subjected to loads which cause stresses and deformations in its cartilaginous structures. A perfect balance between the two sides of the joint is essential to maintain the physiological stress level within the tissues. Therefore, it has been suggested that a derangement of the joint is a contributing factor in the development of mandibular asymmetry, especially if problems of the temporomandibular joint start in childhood or adolescence. To analyze the movement of the mandible and the stresses undergone by the discs, two finite element models of the human temporomandibular joint including the masticatory system were developed, one corresponding to a healthy joint and the other with a unilateral anterior disc displacement with their movement controlled by muscle activation. A fibre‐reinforced porohyperelastic model was used to simulate the behaviour of the articular discs. The stress distribution was analyzed in both models during free opening and closing, and during the introduction of a resistant force between incisors or molars. It was found that a slight unilateral anterior disc displacement does not lead to mandibular asymmetry but to a slight decrease of the maximum gape. With the introduction of a restriction between incisors, the maximum stresses moved to the anterior band in contrast to what happened if the restriction was imposed between molars where maximum stresses were located more posteriorly. Finally, the presence of a unilateral displacement of the disc involved a strong change in the overall behaviour of the joint including also the healthy side, where the maximum stresses moved to the posterior part.
Antipodean Myths Transformed: The Evolution of Australian Identity
Authors: Arthur Paul 
Published: August 2007

AbstractAustralia and the South Pacific held a special status in the eighteenth century: this was the farthest region from Europe and the last part of the earth remaining for Europeans to explore and chart. In the context of European nations’ own histories of discovering and exploring the world beyond Europe's borders, this region is unique in the sense that no other part of the earth had such a substantial and well‐documented body of European thought devoted to it over such a long period of time prior to its physical discovery. The ‘antipodes’ existed in the European imagination for approximately two thousand years before Europeans set foot on antipodean lands. Myths inspired explorers to go searching for the genuine antipodes, and voyages were often undertaken with the specific aim of finding the uncharted places that punctuated otherwise formless maps. Rival European nations, with different aims and agendas, each had their own specific visions of the antipodes that they sought to fulfil through exploration and conquest. Myths of the antipodes had an important role to play in this. Not only did they have the effect of fuelling the desire to find the antipodes, but they also formed a strong foundation for justifying colonisation, on moral and religious grounds. This article outlines a history of antipodean mythology, tracing its representation in European literature and cartography from the classical period to the nineteenth century. The discussion then investigates how these long established mythologies were transformed to produce a prototypical Australian identity in the early colonial period from Australia's British settlement in 1788 to the 1850s. The article concludes by reflecting on continuities of antipodean imagery in perceptions of Oceania today.
A STUDY OF VACUOLARIA VIRESCENS CIENKOWSKI1
Authors: Spencer Lorraine B. 
Published: August 2007

SUMMARYGood collections of Vacuolaria virescens Cienkowski made from a pond in Forsyth County, North Carolina, marks the first recorded appearance of large numbers of this rare genus in the United States. The abundance of this material permitted a careful study of the gross morphology, nuclear structure, organelles, reproduction, and cyst formation, as well as of the ecology of the flagellates. Definitive descriptions of Vacuolaria virescens and V. viridis (Dang.) Senn by European authors are inconsistent and contradictory. Characteristics earlier attributed to each of these species have been found in the American, taxon. Indications are that the taxa described belong to the same species, V. virescens.
THE NUCLEAR CYTOLOGY OF SIROGONIUM1,2
Authors: Wells Charles V. , Hoshaw Robert W. 
Published: August 2007

SUMMARYThe nuclear cytology of 9 strains of Sirogonium is described. The interphase nucleus contains 1–3 nucleoli, a nucleolar‐organizing track, and many (>100) chromocenters. During the division cycle the nucleoli are transformed into a nucleolar substance which becomes associated with the chromosome and is transported through mitosis on the chromosomes. All strains possess minute dot chromosomes varying in length at metaphase from 0.5 to 1.5 μ; satellite chromosomes are 2.5–3.5 μ long. The number of chromosomes varies from 48 ± 2 to 100 ± 2. No evidence of centromeric activity was observed.
CONJUGATION IN SPIROGYRA1
Authors: Fowke Larry C. , Pickett‐Heaps Jeremy D. 
Published: August 2007

SUMMARYConjugating filaments of Spirogyra were examined with both light and electron microscopes. Initially 2 or more filaments of Spirogyra were attached by mucilagenous material. Papillae appeared first in one filament and then in adjacent positions on the other filament. Subsequent growth of papillae separated the conjugating filaments; wall microtubules disappeared in papillae as they elongated. Golgi activity then increased markedly only in the male filament; mucilage production by these Golgi coincided with contraction of the male gamete from its cell wall and may be responsible for its subsequent migration. The end walls separating papillae dissolved to form the conjugation tube, allowing gamete union. The male protoplast then migrated through the tube and further cytoplasmic condensation formed an elliptical‐shaped zygote. During the migration phase, zygote wall formation was initiated and numerous active Golgi apparently contributed material to it. Early zygote maturation was characterized by rapid wall formation and an increase in lipid droplets.
THE LIFE HISTORY OF PIKEA CALIFORNICA HARV.1
Authors: Scott Joseph L. , Dixon Peter S. 
Published: August 2007

SUMMARYControlled environment culture studies have disclosed that Pikea californica has a life history with morphologically dissimilar gametangial and tetrasporangial phases. The effects of light intensity and photoperiod on tetrasporogenesis, cell division, and, cell elongation in the tetrasporangial phase of P. californica are discussed.
ULTRASTRUCTURAL OBSERVATION OF CROSSWALLS IN THE BLUE‐GREEN ALGA SPIRULINA MAJOR1,2
Authors: Holmgren Paul R. , Hosteller H. P. , Scholes Vernon E. 
Published: August 2007

SUMMARY Spirulina major Kütz. was observed with the electron microscope and compared at the ultrastructural level with a species of Arthrospira. The presence, of crosswalls which develop by progressive ingrowth from peripheral walls was demonstrated in S. major. Since cellular septation is not consistent with the generally accepted characters of the genus Spirulina, a taxonomic shift may be indicated.
CARBON, NITROGEN, AND PHOSPHORUS AND THE EUTROPHICATION OF FRESHWATER LAKES1
Authors: Schindler D. W. 
Published: August 2007

SUMMARYThe question of nutrients responsible for eutrophication of freshwater lakes is reviewed, and recent additions to the literature on nutrient limitation are discussed.The paper by Lange is criticized on several grounds, including the facts that utilization of HCO3− by phytoplankton and the invasion of lake waters by atmospheric CO2 are ignored as sources of photosynthetic carbon. The phosphorus and nitrogen concentrations used in Lange's experiments are far higher than values published by others for Lakes Erie and Ontario.Preliminary results of fertilizing a small oligotrophic lake with nitrogen and phosphorus are described. The standing crop of phytoplankton increased by 30–50 ×, while the P:N:C ratio in seston did not change from ratios found in unfertilized lakes. Other experiments done in water columns isolated with polyethylene film showed that addition of carbon did not increase the phytoplankton standing crop. Since the fertilized lake was initially lower in total CO2 than any other recorded in the literature, it is concluded that carbon is unlikely to limit the standing crop of phytoplankton in almost any situation.Measurements of invasion of atmospheric gases to the fertilized lake by the Rn222 technique were compared with phytoplankton production measurements, revealing that atmospheric invasion of CO2 is sufficient to support the high phytoplankton standing crop in the epilimnion of the lake.Possible errors in interpretation of culture and bottle‐bioassay experiments with respect to eutrophication are discussed.
GROWTH AND THE PRODUCTION OF EXTRACELLULAR SUBSTANCES BY TWO STRAINS OF PHAEOCYSTIS POUCHETI1,2
Authors: Guillard R. R. L. , Hellebust Johan A. 
Published: August 2007

SUMMARYClones of Phaeocystis were isolated from winter surface waters off Woods Hole, Massachusetts, and from the tropical Atlantic near Surinam, South America. Northern strains survived only up to 14 C, while the tropical strain survived only as low as 17 C. Colony shapes of the northern and tropical clones differed somewhat, but the motile and non‐motile single cells of both strains seemed identical in the light microscope. By current taxonomic criteria both strains belong to the species P. poucheti (Hariot) Lagerheim.When growing in the form of colonies, both strains excreted 16–64% of their photoassimilated carbon into the medium, mainly as carbohydrates of varying molecular weights. However, cultures predominantly in the form of single cells released only about 3% of their photoassimilated carbon. The qualitative composition of the carbohydrates released is similar for the 2 strains, consisting of some 8 sugars or sugar derivatives with glucose, mannose, and rhamnose as the dominant components. The production of acrylic acid was confirmed. We estimate that as much as 7 μg/liter of acrylic acid, and at least 0.3 mg/liter of polysaccharides can be liberated in a Phaeocystis bloom.
THE CULTURE COLLECTION OF ALGAE AT INDIANA UNIVERSITY–ADDITIONS TO THE COLLECTION JULY 1966–JULY 19711
Authors: Starr Richard C. 
Published: August 2007

SUMMARYOver 250 new strains of algae have been added to the Collection since the latest supplementary list was published in 1966. The formulae for additional maintenance media and for useful experimental media are included. Reprints of this supplementary list and both previous listings are available without charge from the Collection.
OBSERVATIONS ON SNOW ALGAE IN CALIFORNIA1,2
Authors: Thomas William H. 
Published: August 2007

SUMMARYAlgae that impart a red color to snowfields are rather common in California. Red snow occurs mainly in the Sierra Nevada at altitudes of 10,000–12,000 ft (3050–3600 in) and can occur at high altitudes where snow persists in other parts of the state. The distribution in the Sierra was similar in 1969 and 1970, contrasting snowfall years. Colored snow was found from May to October in old, wet snow‐fields. The predominant color was red and occurred as surface patches in depressions in the snow. The color could extend as deep as 30 cm below the snow surface.Algae in the snowfields of the Tioga Pass area (Sierra Nevada) were large, red, spherical cells of Chlamydomonas nivalis. No other algae were seen. Their distribution, as measured by cell numbers and chlorophyll a, was patchy. Algal cells and chlorophyll a were mainly distributed at or near the snow surface but extended down to a depth of 10 cm. Light intensity was greatly attenuated by snow, but enough light for photosynthesis was found at 50 cm below the surface. Nutrient content of one snow sample was very low. The populations were very actively photosynthetic and took up as much as 65% of added 14CO2 in only 3 hr. It was tentatively concluded that CO2 limits in situ photosynthesis. Photosynthesis was inhibited by melting snow samples. Rough calculations of the growth rate suggested in situ generation times of only a few days for these algae.
A QUALITATIVE AND QUANTITATIVE STUDY OF PLASTOQUINONE A IN TWO THERMOPHILIC BLUE‐GREEN ALGAE1
Authors: Sheridan Richard P. 
Published: August 2007

SUMMARYThe thermophilic blue‐green alga Synechococcus lividus strain Y52 was shown to have plastoquinone (PQ) types A, B, and C. The values PQA per cell and chlorophyll a per cell are presented with the changes in the ratio of PQA to chlorophyll a for cells grown at different light intensities.
COMPARATIVE CYTOLOGY OF ULOTHRIX AND STIGEOCLONIUM1
Authors: Floyd Gary L. , Stewart Kenneth D. , Mattox Karl R. 
Published: August 2007

SUMMARYThis investigation describes the cytology of the ulotrichalean genera Ulothrix and Stigeoclonium. Cellular organization is similar to the degree that interphase cells of the 2 genera cannot be distinguished with certainly. In Stigeoclonium, the nuclear envelope becomes disrupted at the end of prophase, and centrioles enter the nucleoplasm. At metaphase the nuclear envelope is again intact, and some of the spindle tubules appear to be contiguous with the nuclear envelope. The spindle in Ulothrix is essentially open with, no attachment of spindle tubules to the nuclear envelope and with, centrioles on the spindle‐cytoplasm interface at the spindle poles. Spindle poles are blunt in Stigeoclonium and pointed in Ulothrix. Cytokinesis is by cell plate formation in both genera, but there is no phragmoplast.
STUDIES ON THE BIOLOGY OF BROWN ALGAE ON THE ATLANTIC COAST OF VIRGINIA. I. PORTERINEMA FLUVIATILE (PORTER) WAERN1,2
Authors: Rhodes Russell G. 
Published: August 2007

SUMMARY Porterinema fluviatile (Porter) Waern has been found, as a microscopic filament on a culm of Spartina from a tidal marsh on the Atlantic coast of Virginia. This represents the first report for Porterinema from a marine site in North, America.
VIRUSLIKE PARTICLES IN THE MARINE ALGA CHORDA TOMENTOSA LYNGBYE (PHAEOPHYCEAE)1
Authors: Toth Ronald , Wilce R. T. 
Published: August 2007

SUMMARYPolyhedral viruslike particles 170 nm in diameter were found in 3‐day‐old spores of the brown alga Chorda tomentosa Lyngbye grown in unsterilized seawater. In sterile seawater, spores of the same species were free of these particles and cell wall development around naked settled, zoospores and subsequent spore germination proceeded, normally. Spores containing the putative virus particles did not develop cell walls or show signs of germination. Severe lysis of cell organelles always accompanied, the presence of these particles.