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Selected AbstractsAtlantic salmon Salmo salar L., brown trout Salmo trutta L. and Arctic charr Salvelinus alpinus (L.): a review of aspects of their life historiesECOLOGY OF FRESHWATER FISH, Issue 1 2003A. Klemetsen Abstract ,,,Among the species in the family Salmonidae, those represented by the genera Salmo, Salvelinus, and Oncorhynchus (subfamily Salmoninae) are the most studied. Here, various aspects of phenotypic and life-history variation of Atlantic salmon Salmo salar L., brown trout Salmo trutta L., and Arctic charr Salvelinus alpinus (L.) are reviewed. While many strategies and tactics are commonly used by these species, there are also differences in their ecology and population dynamics that result in a variety of interesting and diverse topics that are challenging for future research. Atlantic salmon display considerable phenotypic plasticity and variability in life-history characters ranging from fully freshwater resident forms, where females can mature at approximately 10 cm in length, to anadromous populations characterised by 3,5 sea-winter (5SW) salmon. Even within simple 1SW populations, 20 or more spawning life-history types can be identified. Juveniles in freshwater can use both fluvial and lacustrine habitats for rearing, and while most smolts migrate to sea during the spring, fall migrations occur in some populations. At sea, some salmon undertake extensive oceanic migrations while other populations stay within the geographical confines of areas such as the Baltic Sea. At the other extreme are those that reside in estuaries and return to freshwater to spawn after spending only a few months at sea. The review of information on the diversity of life-history forms is related to conservation aspects associated with Atlantic salmon populations and current trends in abundance and survival. Brown trout is indigenous to Europe, North Africa and western Asia, but was introduced into at least 24 countries outside Europe and now has a world-wide distribution. It exploits both fresh and salt waters for feeding and spawning (brackish), and populations are often partially migratory. One part of the population leaves and feeds elsewhere, while another part stays as residents. In large, complex systems, the species is polymorphic with different size morphs in the various parts of the habitat. Brown trout feed close to the surface and near shore, but large individuals may move far offshore. The species exhibits ontogenetic niche shifts partly related to size and partly to developmental rate. They switch when the amount of surplus energy available for growth becomes small with fast growers being younger and smaller fish than slow growers. Brown trout is an opportunistic carnivore, but individuals specialise at least temporarily on particular food items; insect larvae are important for the young in streams, while littoral epibenthos in lakes and fish are most important for large trout. The sexes differ in resource use and size. Females are more inclined than males to become migratory and feed in pelagic waters. Males exploit running water, near-shore and surface waters more than females. Therefore, females feed more on zooplankton and exhibit a more uniform phenotype than males. The Arctic charr is the northernmost freshwater fish on earth, with a circumpolar distribution in the Holarctic that matches the last glaciation. Recent mtDNA studies indicate that there are five phylogeographic lineages (Atlantic, Arctic, Bering, Siberian and Acadian) that may be of Pleistocene origin. Phenotypic expression and ecology are more variable in charr than in most fish. Weights at maturation range from 3 g to 12 kg. Population differences in morphology and coloration are large and can have some genetic basis. Charr live in streams, at sea and in all habitats of oligotrophic lakes, including very deep areas. Ontogenetic habitat shifts between lacustrine habitats are common. The charr feed on all major prey types of streams, lakes and near-shore marine habitats, but has high niche flexibility in competition. Cannibalism is expressed in several cases, and can be important for developing and maintaining bimodal size distributions. Anadromy is found in the northern part of its range and involves about 40, but sometimes more days in the sea. All charr overwinter in freshwater. Partial migration is common, but the degree of anadromy varies greatly among populations. The food at sea includes zooplankton and pelagic fish, but also epibenthos. Polymorphism and sympatric morphs are much studied. As a prominent fish of glaciated lakes, charr is an important species for studying ecological speciation by the combination of field studies and experiments, particularly in the fields of morphometric heterochrony and comparative behaviour. [source] Selenium Deficiency Associated with Cardiomyopathy: A Complication of the Ketogenic DietEPILEPSIA, Issue 4 2003A. G. Christina Bergqvist Summary: ,Purpose: The ketogenic diet (KD) is an efficacious treatment for intractable epilepsy, associated with infrequent side effects. The KD is known to be deficient in most vitamins and minerals and may be deficient in trace minerals. We report biochemical selenium deficiency in nine patients on the KD, including one who developed cardiomyopathy. Methods: A whole-blood selenium level was obtained on the symptomatic patient after noting the patient's poor appearance on physical examination. Children already treated and children beginning the KD were then evaluated prospectively for selenium status by measuring whole-blood or serum selenium as part of routine laboratory evaluation every 3 months. Results: The index case had no detectable whole-blood selenium. Cardiac physical examination and ECG were normal, but the echocardiogram revealed cardiomyopathy. Thirty-nine additional children had the selenium status evaluated. Eight had selenium levels below the normal range (six initially, and two developed low selenium levels on serial testing). They were referred for cardiology evaluations, which were normal. Selenium supplementation improved levels in all children. Low levels were seen in some children after only a few months of treatment. Conclusions: The nutrient adequacy of the currently used KD has not been fully evaluated. The nutrient content of KD with usual supplements may not meet Recommended Dietary Allowances (RDA) for selenium and may not provide other trace minerals in adequate amounts. At our center, selenium deficiency was found in 20% of the patients evaluated. Screening for selenium deficiency is suggested if the patient KD regimen does not meet ,75% of the RDA or if the child is symptomatic. Nutrient supplementation should provide adequate trace elements for children treated with the KD. The KD requires close monitoring of the overall nutritional status. [source] Long-term monitoring of the intra-day variable quasar PKS 0405,385MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2006L. Kedziora-Chudczer ABSTRACT The quasar PKS 0405,385 is one of three radio sources (the other two are PKS 1257,326 and J1819+385) which exhibit unusually strong and rapid interstellar scintillations at GHz frequencies. Such a behaviour suggests a nearby (<30 pc away) scattering screen along the line of sight to these radio sources. While quasars PKS 1257,326 and J1819+385 scintillate continuously over several years of monitoring, PKS 0405,385 shows episodes of strong scintillations which last only a few months. Here, I present the results of flux-density monitoring of PKS 0405,385 over 6 yr at four Stokes parameters and four frequencies. Two explanations of the episodic behaviour of interstellar scintillation in this source are discussed; morphological evolution of the source and changes in the properties of the interstellar medium along the line of sight. [source] Field Reliability Prediction in Consumer Electronics Using Warranty DataQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 4 2007Roxana A. Ion Abstract In innovative fast product development processes, such as consumer electronics, it is necessary to check as quickly as possible, using field data, whether the product reliability is at the right level. In consumer electronics, some major companies use the Warranty Call Rate (WCR) for this purpose. This paper discusses extensively the theoretical and practical drawbacks of the WCR. Subsequently, it is demonstrated, using a Weibull failure distribution, that only a few months after product launch, say three months, the warranty data offer the opportunity to estimate the parameters of the failure distribution. Of course, this requires that the warranty data are available in the quality department. Unfortunately, for some companies the field feedback information process from the repair centres to the quality department causes a delay of several months. These companies have to speed up their field feedback information process before they can fully take advantage of the proposed estimation procedure. Copyright © 2006 John Wiley & Sons, Ltd. [source] Multi-institutional phase II study of temozolomide administered twice daily in the treatment of recurrent high-grade gliomas,CANCER, Issue 5 2008Casilda Balmaceda MD Abstract BACKGROUND. The prognosis for patients with recurrent high-grade gliomas is poor and treatment options are limited. Current chemotherapeutic regimens can improve clinical outcomes, but extend survival by only a few months. Temozolomide is a methylating agent that is typically administered once daily. Because preclinical studies suggested that a twice-daily dosing schedule might be more effective, the safety and efficacy of twice-daily dosing of temozolomide were studied in patients with recurrent gliomas at their first, second, or third recurrence. METHODS. This multi-institutional trial enrolled 120 patients with recurrent glioblastoma multiforme (GBM), anaplastic astrocytoma (AA), or anaplastic oligodendroglioma (AO). An initial oral dose of 200 mg/m2 of temozolomide was followed by 9 consecutive doses of 90-mg/m2 every 12 hours. Treatment cycles were repeated every 28 days. Doses were escalated to 100 mg/m2 twice daily in the absence of unacceptable toxicity or were reduced if unacceptable toxicity occurred. RESULTS. For GBM, AA, and AO patients, respectively, the median progression-free survival (PFS) was 4.2 months, 5.8 months, and 7.7 months, whereas the median overall survival (OS) was 8.8 months, 14.6 months, and 18 months. The overall response rate (partial and complete) for the GBM, AA, and AO patients was 31%, 46%, and 46%, respectively. Grade 3/4 toxicities included neutropenia (1.1%), thrombocytopenia (3.6%), and anemia (0.3%) (graded according to the World Health Organization grading system). CONCLUSIONS. Twice-daily dosing may enhance the efficacy of temozolomide in the treatment of recurrent gliomas without increasing toxicity. This regimen compares favorably with other dosing schedules of temozolomide reported in the literature. Cancer 2008. © 2008 American Cancer Society. [source] | ||||||||||