bluuebunny/crossref_metadata_2025 huggingface dataset:
Berechnungstafeln für den Konstruktiven Glasbau
Authors: Weller Bernhard , Reich Stefan , Wünsch Jan
Published: May 2006

Im Konstruktiven Glasbau werden für Verglasungen zu einem Großteil rechteckige, allseits linienförmig gelagerte Gläser eingebaut. Aufgrund der begrenzten Anzahl von Lastfällen ist es für diese Verglasungen nicht immer erforderlich, numerische Modelle für die Berechnung zu nutzen. Mit Hilfe der linearen Plattentheorie werden Berechnungstafeln für den Konstruk‐tiven Glasbau erstellt, die häufig auftretende Situationen behandeln. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interaction of Alfvén front with the plasma anomalous resistance layer
Authors: MAZUR N. , FEDOROV E. , PILIPENKO V. , LEONOVICH A.
Published: May 2006

The efficiency of the Alfvén impulse excitation in the auroral zone of the terrestrial magnetosphere upon the onset of the anomalous field-aligned resistance has been estimated. The impulsive disturbance excited during the onset of anomalous field-aligned resistance and electric field may signify the transition of a global magnetospheric instability into the explosive phase with positive feedback. We consider the self-consistent problem on excitation of anomalous resistance at the front of field-aligned current and reverse influence upon it from the induced currents. The analytical solution of the self-consistent problem has shown that during the entrance of field-aligned current front into the anomalous resistivity layer (ARL) an Alfvénic impulse is generated. The interaction of the external current with ARL results in the delay of the current growth. The impulse duration and delay time depend on the ratio between the Alfvén damping scale and external current width. The solution obtained indicates the possibility of using the Alfvénic impulse as an indicator of distant occurrence of anomalous resistance.
Older substance misusers still deserve better services – an update (Part 1)
Authors: Crome Ilana , Bloor Roger
Published: May 2006

This review is the first in a three-part series on substance problems in older people. This section reviews terminology, epidemiology, outcome studies and policy directions. Subsequent articles will provide an overview of assessment, physical and psychological co-morbidity, as well as treatment options.
Management and implications of chronic obstructive pulmonary disease (COPD) for older patients
Authors: Ruse Charlotte E , Molyneux Andrew W P
Published: May 2006

Airflow obstruction is common in older persons but frequently under-diagnosed. The term refers to a spectrum of chronic respiratory disorders characterized by cough, dyspnoea, mucus hypersecretion, wheeze and impaired pulmonary function tests. Patients may be diagnosed as having late-onset asthma, chronic obstructive pulmonary disease (COPD), chronic bronchitis, emphysema or fixed airflow obstruction of the elderly.
The Effects of Marginal Deviations on Behavioral Development
Authors: Caprara Gian Vittorio , Dodge Kenneth A. , Pastorelli Concetta , Zelli Arnaldo
Published: May 2006

This investigation was conceptually framed within the theory of marginal deviations ( Caprara & Zimbardo, 1996 ) and sought evidence for the general hypothesis that some children who initially show marginal behavioral problems may, over time, develop more serious problems depending partly on other personal and behavioral characteristics. To this end, the findings of two studies conducted, respectively, with American elementary school children and Italian middle school students are reviewed. These two studies show that hyperactivity, cognitive difficulties, low social preference, and lack of prosocial behavior increase a child's risk for growth in aggressive behavior over several school years. More importantly, they also show that equivalent levels of these risk factors have a greater impact on the development of children who, early on, were marginally aggressive.
ASK-1 (apoptosis signal-regulating kinase 1) is a direct E2F target gene
Authors: Kherrouche Zoulika , Blais Alexandre , Ferreira Elisabeth , De Launoit Yvan , Monté Didier
Published: May 2006

In the present study, we show that E2Fs (E2 promoter-binding factors) regulate the expression of ASK-1 (apoptosis signal-regulating kinase 1), which encodes a mitogen-activated protein kinase kinase kinase, also known as MAP3K5. Its mRNA expression is cell-cycle-regulated in human T98G cells released from serum starvation. Moreover, overexpression and RNA interference experiments support the requirement of endogenous E2F/DP (E2F dimerization partner) activity for ASK-1 expression. Characterization of the human ASK-1 promoter demonstrates that the −95/+11 region is critical for E2F-mediated up-regulation. Chromatin immunoprecipitation assays show that E2F1–E2F4 are bound in vivo to the ASK-1 promoter in cycling cells, probably through a non-consensus E2F-binding site located 12 bp upstream of the transcription start site. Mutation of this site completely abolishes the ASK-1 promoter response to E2Fs as well as the E2F1 binding in electrophoretic mobility-shift experiments. Our results indicate that E2Fs modulate the expression of ASK-1 and suggest that some of the cellular functions of ASK-1 may be under the control of E2F transcription factors. Moreover, the up-regulation of ASK-1 may also favour the p53-independent E2F1 apoptotic activity.
Evaluation of the membrane-spanning domain of ClC-2
Authors: Ramjeesingh Mohabir , Li Canhui , She Yi-Min , Bear Christine E.
Published: May 2006

The ClC family of chloride channels and transporters includes several members in which mutations have been associated with human disease. An understanding of the structure–function relationships of these proteins is essential for defining the molecular mechanisms underlying pathogenesis. To date, the X-ray crystal structures of prokaryotic ClC transporter proteins have been used to model the membrane domains of eukaryotic ClC channel-forming proteins. Clearly, the fidelity of these models must be evaluated empirically. In the present study, biochemical tools were used to define the membrane domain boundaries of the eukaryotic protein, ClC-2, a chloride channel mutated in cases of idiopathic epilepsy. The membrane domain boundaries of purified ClC-2 and accessible cysteine residues were determined after its functional reconstitution into proteoliposomes, labelling using a thiol reagent and proteolytic digestion. Subsequently, the lipid-embedded and soluble fragments generated by trypsin-mediated proteolysis were studied by MS and coverage of approx. 71% of the full-length protein was determined. Analysis of these results revealed that the membrane-delimited boundaries of the N- and C-termini of ClC-2 and the position of several extramembrane loops determined by these methods are largely similar to those predicted on the basis of the prokaryotic protein [ecClC (Escherichia coli ClC)] structures. These studies provide direct biochemical evidence supporting the relevance of the prokaryotic ClC protein structures towards understanding the structure of mammalian ClC channel-forming proteins.
Ammonium ion transport by the AMT/Rh homologue LeAMT1;1
Authors: Mayer Maria , Dynowski Marek , Ludewig Uwe
Published: May 2006

AMT (ammonium transporter)/Rh (Rhesus) ammonium transporters/channels are identified in all domains of life and fulfil contrasting functions related either to ammonium acquisition or excretion. Based on functional and crystallographic high-resolution structural data, it was recently proposed that the bacterial AmtB (ammonium transporter B) is a gas channel for NH3 [Khademi, O'Connell, III, Remis, Robles-Colmenares, Miercke and Stroud (2004) Science 305, 1587–1594; Zheng, Kostrewa, Berneche, Winkler and Li (2004) Proc. Natl. Acad. Sci. U.S.A. 101, 17090–17095]. Key residues, proposed to be crucial for NH3 conduction, and the hydrophobic, but obstructed, pore were conserved in a homology model of LeAMT1;1 from tomato. Transport by LeAMT1;1 was affected by mutations of residues that were predicted to constitute the aromatic recruitment site for NH4+ at the external pore entrance. Despite the structural similarities, LeAMT1;1 was shown to transport only the ion; each transported 14C-methylammonium molecule carried a single positive elementary charge. Similarly, NH4+ (or H+/NH3) was transported, but NH3 conduction was excluded. It is concluded that related proteins and a similar molecular architecture can apparently support contrasting transport mechanisms.
Molecular cloning, expression and characterization of pyridoxamine–pyruvate aminotransferase
Authors: Yoshikane Yu , Yokochi Nana , Ohnishi Kouhei , Hayashi Hideyuki , Yagi Toshiharu
Published: May 2006

Pyridoxamine–pyruvate aminotransferase is a PLP (pyridoxal 5′-phosphate) (a coenzyme form of vitamin B6)-independent aminotransferase which catalyses a reversible transamination reaction between pyridoxamine and pyruvate to form pyridoxal and L-alanine. The gene encoding the enzyme has been identified, cloned and overexpressed for the first time. The mlr6806 gene on the chromosome of a symbiotic nitrogen-fixing bacterium, Mesorhizobium loti, encoded the enzyme, which consists of 393 amino acid residues. The primary sequence was identical with those of archaeal aspartate aminotransferase and rat serine–pyruvate aminotransferase, which are PLP-dependent aminotransferases. The results of fold-type analysis and the consensus amino acid residues found around the active-site lysine residue identified in the present study showed that the enzyme could be classified into class V aminotransferases of fold type I or the AT IV subfamily of the α family of the PLP-dependent enzymes. Analyses of the absorption and CD spectra of the wild-type and point-mutated enzymes showed that Lys197 was essential for the enzyme activity, and was the active-site lysine residue that corresponded to that found in the PLP-dependent aminotransferases, as had been suggested previously [Hodsdon, Kolb, Snell and Cole (1978) Biochem. J. 169, 429–432]. The Kd value for pyridoxal determined by means of CD was 100-fold lower than the Km value for it, suggesting that Schiff base formation between pyridoxal and the active-site lysine residue is partially rate determining in the catalysis of pyridoxal. The active-site structure and evolutionary aspects of the enzyme are discussed.
Subcellular targeting and trafficking of nitric oxide synthases
Authors: Oess Stefanie , Icking Ann , Fulton David , Govers Roland , Müller-Esterl Werner
Published: May 2006

Unlike most other endogenous messengers that are deposited in vesicles, processed on demand and/or secreted in a regulated fashion, NO (nitric oxide) is a highly active molecule that readily diffuses through cell membranes and thus cannot be stored inside the producing cell. Rather, its signalling capacity must be controlled at the levels of biosynthesis and local availability. The importance of temporal and spatial control of NO production is highlighted by the finding that differential localization of NO synthases in cardiomyocytes translates into distinct effects of NO in the heart. Thus NO synthases belong to the most tightly controlled enzymes, being regulated at transcriptional and translational levels, through co- and post-translational modifications, by substrate availability and not least via specific sorting to subcellular compartments, where they are in close proximity to their target proteins. Considerable efforts have been made to elucidate the molecular mechanisms that underlie the intracellular targeting and trafficking of NO synthases, to ultimately understand the cellular pathways controlling the formation and function of this powerful signalling molecule. In the present review, we discuss the mechanisms and triggers for subcellular routing and dynamic redistribution of NO synthases and the ensuing consequences for NO production and action.
Governing Space: Planning Reform and the Politics of Sustainability
Authors: Cowell Richard , Owens Susan
Published: May 2006

The authors explore the relationship between land-use, or spatial, planning and the environmental sustainability of major areas of public policy. First, the planning–public policy relationship is conceptualised within a framework that challenges narrowly instrumental accounts of the role of planning in the promotion of environmental sustainability, emphasising instead how the exploitation of opportunity structures in planning has impinged over time on dominant sectoral objectives. This framework is then used to analyse reformist pressures on planning, with particular reference to England's ‘modernising planning’ agenda. The argument is developed through a critical analysis of how, in the light of key components of this agenda—rescaling, streamlining, and the introduction of a statutory purpose—planning, public policy, and environmental sustainability might be expected to interact in future. Early signs suggest that the initial reform proposals—to accelerate the delivery of development by restructuring opportunities for participation—were diluted (but not displaced) by strong opposition. Tracing the long-term impacts of the reforms will require research into the relations between the reconstituted tiers of planning and the ability of interest groups to use the new opportunity structures effectively—tasks that should interest analysts of the greening of the state as much as planning researchers.
When Water Management Meets Spatial Planning: A Policy-Arrangements Perspective
Authors: Wiering Mark , Immink Irene
Published: May 2006

In water management and in spatial planning there is a debate on the fundamental underlying discourses of the policy domains. In Dutch water management an emergent discourse of ‘accommodating water’, which is competing with the traditional ‘battle against water’ discourse, can be seen. In Dutch spatial planning there is a debate on new practices of area-specific development planning, which are considered to reflect new ideas on spatiality better than the traditional Dutch planning doctrine. The authors discuss these recent developments, and attempt to analyse institutional changes with the help of the perspective of policy arrangements. The analysis is focused on the interrelations between the two policy arrangements, and both new ‘rules of the game’ and new policy practices are considered. The question is posed as to whether these practices are forerunners of new arrangements or do they merely reflect a revised policy and planning agenda of the existing institutional order?
Green Niches in Sustainable Development: The Case of Organic Food in the United Kingdom
Authors: Smith Adrian
Published: May 2006

Strategic niche management is a recently developed policy approach which advocates claim, is important in seeding radical transformations in sociotechnical regimes, and transitions to environmentally sustainable regimes in particular. This paper examines a critically important aspect of this approach: the relationship between radically novel sociotechnical practices in niches and the mainstream social–technical regimes they seek to influence. Although the literature notes the significance of this relationship, it does so in a paradoxical way. It is argued that niches are more likely to influence mainstream change when they show a degree of compatibility with the incumbent regime. Yet this compatibility criterion blunts the scope for niches to be radically innovative, thereby undermining the degree of regime transformation being sought. The case of organic food is used to explore this paradox empirically. The history of the organic niche, and its engagement and entanglement with the mainstream food regime, suggests a dialectical relationship between sociotechnical niches and regimes.
Developing Leisure and Cultural Attractions in the Regional City Centre: A Policy Perspective
Authors: Tallon Andrew R , Bromley Rosemary D F , Reynolds Ben , Thomas Colin J
Published: May 2006

Smaller regional cities and former industrial cities throughout North America and Europe have experienced fundamental transformations of their economies over recent decades, and authorities have continually sought new functions for the postindustrial era. Following on from retail, office, and residential regeneration within many city centres, leisure and cultural policies have also been adopted. The British city of Swansea, which has developed such policies since the 1990s, is a regional city which typifies these processes. Drawing on large-scale surveys and in-depth interviews, the authors argue that four policy challenges are facing the development of a thriving leisure and cultural economy in smaller regional cities across Europe and North America. These challenges involve creating a leisure and cultural economy which: embraces a wide range and variety of attractions; appeals to a broad spectrum of social groups; adopts an appropriate spatial strategy; and overcomes friction between the different component parts of the leisure and cultural economy.
The Institutional Limits to Multifunctional Agriculture: Subnational Governance and Regional Systems of Innovation
Authors: Clark Julian
Published: May 2006

The author adopts a regional innovation systems approach to examine how subnational governance is implicated in the promotion of multifunctional agricultural strategies in England. Multifunctionality has been advocated as a pivotal concept for orchestrating the promotion of so-called ‘postproductivist’ agricultural policies, with researchers identifying different interpretations in European states based upon national political priorities and production structures. However, to date no attempt has been made to conceptualise the institutional capacities required to deliver this innovative policy mandate, or to assess the challenges confronting regional governance in the translation of opaque multifunctional discourses into concrete, implementable, policies. These critically important research issues are examined with the aid of primary and secondary datasets derived from the English East Midlands.
Dancing Shapes: A Comparison of Luminance-Induced Distortions
Authors: van Lier Rob , Csathó Árpád
Published: May 2006

We present an illusory display in which a grid of outlined squares is positioned in front of a moving luminance gradient. Observers perceive a strong, illusory, ‘wavelike’ motion of the superimposed squares. We compared luminance effects on dynamic and static aspects of this illusion. The dynamic aspect was investigated by means of a temporal gradient, which induced an illusory pulsing of the outlined squares. The static aspect was investigated in two different ways. In one experiment, the outlined squares were positioned on a spatial gradient, which caused the squares to look like trapezoid shapes. In another experiment, the squares were positioned on different luminance fields, which affected their apparent size. In all experiments, luminance settings were the same, and observers were asked to indicate the direction and strength of the induced distortions. The overall results show large agreements between the dynamic distortion and the first-mentioned static distortion, whereas different tendencies emerged for the second static distortion. In a second series of experiments, we examined these distortions for various ranges of the luminance gradient and for border gradients as well. On the basis of these data, we explored how the directions of the perceived distortions of the single-gradient displays examined in this paper could be related to each other.
The Evolution of Explanations of a Perceptual Phenomenon: A Case History Using the Ternus Effect
Authors: Petersik J Timothy , Rice Curran M
Published: May 2006

The Ternus effect involves a multi-element stimulus that can lead to either of two different percepts of apparent movement depending upon a variety of stimulus conditions. Since Ternus's 1926 discussion of this phenomenon, many researchers have attempted to explain it. We examine the history of explanations of the Ternus effect and show that they have evolved to contemporary theoretical positions that are very similar to Ternus's own ideas. Additionally, we describe a new experiment showing that theoretical positions that emphasize element grouping and element identity within groups can predict the effects of certain stimulus manipulations on the Ternus effect.
Savant-like Numerosity Skills Revealed in Normal People by Magnetic Pulses
Authors: Snyder Allan , Bahramali Homayoun , Hawker Tobias , Mitchell D John
Published: May 2006

Oliver Sacks observed autistic twins who instantly guessed the exact number of match-sticks that had just fallen on the floor, saying in unison “111”. To test the suggestion that normal individuals have the capacity for savant numerosity, we temporarily simulated the savant condition in normal people by inhibiting the left anterior temporal lobe of twelve participants with repetitive transcranial magnetic stimulation (rTMS). This site has been implicated in the savant condition. Ten participants improved their ability to accurately guess the number of discrete items immediately following rTMS and, of these, eight became worse at guessing as the effects of the pulses receded. The probability of as many as eight out of twelve people doing best just after rTMS and not after sham stimulation by chance alone is less than one in one thousand.
Expression of barley BAX Inhibitor‐1 in carrots confers resistance to Botrytis cinerea
Authors: IMANI JAFARGHOLI , BALTRUSCHAT HELMUT , STEIN ELKE , JIA GENGXIANG , VOGELSBERG JÖRG , KOGEL KARL‐HEINZ , HÜCKELHOVEN RALPH
Published: May 2006

BAX Inhibitor‐1 (BI‐1) is a protein that controls heterologous BAX‐induced cell death, the hypersensitive reaction and abiotic stress‐induced cell death in plants. When over‐expressed in epidermal cells of barley, barley BI‐1 induces susceptibility to the biotrophic fungal pathogen Blumeria graminis. When we expressed barley BI‐1 in carrot susceptible to the necrotrophic fungus Botrytis cinerea, we obtained BI‐1‐mediated resistance to fungus‐induced leaf cell death and less fungal spreading on the leaves. Barley BI‐1 also mediated resistance to Chalara elegans in carrot roots. The results support the idea that cell death inhibition is an applicable approach to control cell‐death‐inducing pathogens in crop plants.
The potential impacts of the arrival of the harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in Britain
Authors: Majerus Michael , Strawson Vicky , Roy Helen
Published: May 2006

Abstract.  1. The harlequin ladybird, Harmonia axyridis, has recently arrived in Britain.

2. This species has been introduced from Asia into many parts of the world for biological control purposes.

3. In many parts of North America it has become the predominant aphidophagous coccinellid in less than 20 years, and in north‐western Europe it is spreading and increasing in number rapidly.

4. Since establishment in North America and continental Europe, reports of its effectiveness as a biological control agent of aphids and coccids have been accompanied by accounts of negative effects on other aphidophagous species and humans.

5. Here the potential impacts of the arrival of the harlequin ladybird in Britain are assessed.
Trade‐off in oviposition strategy: choosing poor quality host plants reduces mortality from natural enemies for a salt marsh planthopper
Authors: MOON DANIEL C. , STILING PETER
Published: May 2006

Abstract 1. Both host plant nutrition and mortality from natural enemies have been predicted to significantly impact host plant selection and oviposition behaviour of phytophagous insects. It is unclear, however, if oviposition decisions maximise fitness.

2. This study examined whether the salt marsh planthopper Pissonotus quadripustulatus prefers higher quality host plants for oviposition, and if oviposition decisions are made so as to minimise mortality at the egg stage.

3. A controlled laboratory experiment and 4 years of field data were used to assess the rates of planthopper oviposition on higher quality ‘green’ and lower quality ‘woody’ stems of the host plant Borrichia frutescens. The numbers and percentages of healthy eggs and eggs that were killed by parasitoids or the host plant were recorded.

4. In all years, including the laboratory experiment, Pissonotus planthoppers laid more eggs on lower quality woody stems than on higher quality green stems. While host plant related egg mortality was higher in woody stems, the percentage of eggs parasitised was much greater in green stems. This resulted in a lower total mortality of eggs on woody stems.

5. The results of this study demonstrate that, although Pissonotus prefers lower quality host plants for oviposition, this actually increases fitness. These data seem to support the enemy free space hypothesis, and suggest that for phytophagous insects that experience the majority of mortality in the egg stage, oviposition choices may be made such that mortality is minimised.
Helminth parasite populations in newts and their tadpoles
Authors: AVERY R. A.
Published: May 2006

Five species of helminth parasites were found in adults and tadpoles of the newts Triturus helveticus, T. vulgaris, and T. cristatus, caught at eight different localities in Somerset. These parasites were Acanthocephalus anthuris, A. ranae, Megalobatra‐chonema terdentatum, Thominx filiformis and Oswaldocruzia molgeta. Mean worm burdens did not change through the year, and egg‐producing females of Acantho‐cephalus anthuris and Megalobatrachonema terdentatum were found throughout. There was no difference in the level of infection of male and female newts.
The autecology of the chub, Squalius cephalus (L.), of the River Lugg and the Afon Llynfi
Authors: HELLAWELL J. M.
Published: May 2006

(1) The pattern of absolute atid relative gonad growth during the life‐span and the seasonal gotiad cycle were determined from monthly samples of chub taken from two tributaries of the Herefordshire Wye.

(2) A marked change in the pattern of absolute gonad growth was thought to indicate the attainment of sexual maturity. This was found to occur synchronously with corresponding changes in the pattern of body growth described previously and was in agreement with the age at which a seasonal gonad cycle was detectable.

(3) Sexual maturity was attained during the eighth year of life (7+) in female chub and in males from the Afon Llynfi, but most males from the River Lugg matured a year earlier.

(4) The chub gonads continued to increase in relative size after the attainment of sexual maturity. This was more evident in female chub.

(5) Seasonal changes in the gonad condition and weight were followed. Gonad maturation occurred during spring and the gonad mass increased rapidly just prior to spawning.

(6) Spawning occurred during June.
Primary production and respiration of the phytoplankton of the Rivers Thames and Kennet at Reading
Authors: KOWALCZEWSKI A. , LACK T. J.
Published: May 2006

During the period April 1967‐ApriI 1968 the phytoplankton production and respiration of the River Thames and its tributary, the River Kennet, were measured at approxi‐mately 2‐week intervals using the light and dark bottle technique. Concentrations of chlorophyll and pheopigment were determined weekly. On fourteen occasions sets of light and dark bottles were rotated in a specially designed apparatus, and production and respiration values obtained were found to be 1·38 ± 0·31 times higher than in stationary bottles at identical depths over the same period. There was little horizontal, vertical or diurnal variation in chlorophyll concentration showing that the water was well mixed. Peaks of chlorophyll were found in spring, summer and autumn in the Thames (max. 219 mg/m3) but there was very little variation in the Kennet (max. 38·2 mg/m3). In both rivers lowest concentrations were found during winter. Pheo‐pigment concentration was low in both rivers for most of the period although in the Kennet this represented on average 50% of the pigments present. In the Thames a peak of pheopigments(1·33–5 mg/m3) was associated with the autumnal bloom and repre‐sented 61 % of the total pigments. No pheopigments were detected during the spring bloom. The average concentration of suspended organic matter was identical in both rivers but in the Thames over 25 % was due to phytoplankton and in the Kennet almost 95 % was non‐algal.

In the Thames, net oxygen production reached a peak in May (10·81 gO2/m2/day) and was negative from November to February (min. −0·45 gO2/m2/day). In the Kennet, maximum production also occurred in May (0·85 gO2/m2) but was negative from the middle of May until the following March. The average annual net production was 1250 and −78 g O2/m2 in the Thames and Kennet respectively.

Respiration rates showed similar fluctuations being 4·59 g O2/m2/day in spring in the Thames to 0·09 g O2/m2/day in November. The Kennet was almost always lower (1·05–0·34 g O2/m2/day. The average annual respiration was almost three times higher in the Thames than in the Kennet (641–228 g O2/m2).

Various factors which might influence production are discussed. The average net efficiency ofthe Thames phytoplankton fell within ranges described from other rivers. Net efficiencies ofthe Kennet were almost always negative.

In the Thames it appeared that net production could be explained as a function of solar radiation, chlorophyll concentration and euphotic depth.
A survey of the macro‐fauna of the River Cynon, a polluted tributary of the River Taff (South Wales)
Authors: LEARNER M. A. , WILLIAMS R. , HARCUP M. , HUGHES B. D.
Published: May 2006

(1) A survey of the macro‐invertebrates and fish in the River Cynon, a trout stream in south‐east Wales receiving industrial and domestic wastes, and nine of its tributaries, was carried out in the summer of 1970. Its principal purpose was to describe the structure of these communities before waste treatment facilities, in course of construction, reduce the degree of pollution.

(2) The macro‐invertebrate communities changed dramatically at station C4, there being a very varied fauna upstream and one dominated by chironomids and oligochaetes downstream, principally Nais barbata., Cricotopus bicinctus and Syncricotopus rufiventris. It seems likely that coal particles, influencing the substrate, are largely responsible for this change. Further downstream, and below substantial organic discharges, tubificids and the enchytraeid, Lumbricillus rivalis, became increasingly abundant. The total density of macro‐invertebrates increased from about 2000/m2 in the headwaters to over 20,000/m2 in the lower reaches.

(3) The fauna of the clean tributaries, Hir (C16) and Wenallt (C19) was similar to that ofthe unpolluted upper reaches ofthe Cynon (C1‐C3) whereas that of tributaries affected by coal particles was similar to the fauna of the Cynon downstream of C4.

(4) Six species of fish were recorded (bullhead, eel, minnow, trout, stickleback and stoneloach) of which tbree (bullhead, eel and trout) were confined to reaches upstream (C8 and above) of industrial eflluents at Abercwmboi. For 0–8 km downstream of these effluents the river was fishless and further downstream, to the confluence with the River Taff, fish density and biomass were reduced.

(5) In the upper Cynon and its tributaries the density and biomass of trout were within the range recorded elsewhere in the British Isles. The growth rate of trout in the catchment is low. Diflerences in growth rate and shape of trout in the main river and tributaries suggest that there is little interchange between these areas, except perhaps with very young fish. 0 +* fish were only caught in abundance at two tributary stations and their numbers, even if widely distributed, could not permanently support the current density of older fish throughout the upper catchment.

(6) Stone loach and minnow reached a very large size and individuals caught of the latter species approached the maximum recorded length for the British Isles.
The autecology of the chub, Squalius cephalus (L.), of the River Lugg and the Afon Llynfi
Authors: HELLAWELL J. M.
Published: May 2006

(1) Seasonal variation in the intensity of feeding activity was demonstrated in two chub populations. Feeding activity was higher in summer and more pronounced in the young age‐classes. The intensity of feeding activity was significantly correlated with temperature.

(2) The diet of the total chub populations embraced a wide range of food items but vegetable material predominated. Substrate material was frequently encountered which suggested considerable feeding on the river bed. Fish were the most important animal food, by volume, in the River Lugg but Trichoptera larvae were most important in the Afon Llynfi. No remains of salmon parr or trout were found in chub stomachs but grayling were eaten. The most important prey fish, by volume, was the eel but cyprinids, especially minnows, were most important by frequency of occurrence.

(3) Seasonal variation in the composition of the diet could be related to availability of food organisms but some selection was shown. Vegetable foods were most important in summer; animal foods, Trichoptera larvae in particular, were important in winter.

(4) Analysis of the variation in the composition of the diet with age revealed several trends, notably a decrease in the importance of plant material, aquatic and aerial insects with age and a corresponding increase in the importance of larger prey foods such as fish, frogs and crayfish.

(5) The commonly held view that chub are deleterious to salmonid stocks was examined. The absence of direct predation and the small likelihood of direct competition suggests that this view is incorrect.
Phosphorus availability and nitrogenase activity in aquatic blue‐green algae
Authors: STEWART W. D. P. , ALEXANDER GAIL
Published: May 2006

Metabolically active phosphorus‐starved cultures of blue‐green algae assimilate 32P rapidly in the light and in the dark. The uptake of phosphorus results in a rapid (within 15 min) stimulation in acetylene reduction by Anabaena cylindrica, A. flosaquae, Anabacnopsis circuiaris and Chlorogloea fritschii, with a response being obtained to less than 5 μg/1 of phosphorus. Uptake of phosphorus also causes a rapid increase in respiration in the dark but not in photo respiration, and the size of the cellular ATP pool and the 14CO2 fixation rate both increase more slowly. The metabolism of phosphorus‐sufficient cells, which assimilate phosphorus more slowly, shows little response when phosphorus is provided.

Excess phosphorus is stored in the vegetative cells of blue‐green algae as polyphosphate bodies which may form within 60 min of adding phosphorus to phosphorusstarved cells and which serve as a source of phosphorus for the algae when exogenous phosphorus is limiting. Preliminary results from Scottish waters suggest that urban effluents are important sources of available‐phosphorus for algal growth and that the levels entering fresh waters from agricultural land are, per unit volume, lower. In both types of water the levels of available‐phosphorus are rather similar to the levels of orthophosphate‐phosphorus present. Most detergents tested serve as a source of phosphorus for nitrogen‐fixing blue‐green algae and cause a rapid stimulation in reduction when added to phosphorus‐starved cultures. Of the detergents assayed, the biological types were richest in available phosphorus. The addition of detergents may result in a rapid increase in number of polyphosphate bodies present in the algae. Detergents in general also contain an inhibitor of algal metabolism. Whether a stimu‐lation or an inhibition occurs depends on the quantities of detergent added and on whether or not the alga is phosphorus‐deficient.
The Ephemeroptera of the River Bela, Westmorland
Authors: COLLINS J. M.
Published: May 2006

Though larger and more calcareous than a Lake District Beck, the River Bela now harbours a similar community of Ephemeroptera. Three species characteristic of small rivers were not recorded after the sides had been straightened and cleared of emergent vegetation and the bottom had been levelled.
The effects of sand deposition upon the macroinvertebrate fauna of the River Camel, Cornwall
Authors: NUTTALL P. M.
Published: May 2006

Erosion from a tributary of the River Camel deposited an estimated 10,000 m3 of sand in the main river over a period of 2 years. The poor incidence of plants and macro‐invertebrates from the river was associated with the unstable shifting nature of the sand deposits, rather than turbidity or abrasion caused by particles in suspension. Sand deposition accounted for the low diversity of invertebrate species below the tributary, and resulted in the elimination of several species which were frequent upstream. Baetis rhodani, Rhithrogena semicolorata, and Tubificidae were abundant where sand deposition had occurred.
An examination of subspecific differences in the merus of the fifth walking leg of the amphipod Gammarus duebeni Lilljeborg
Authors: SUTCLIFFE D. W.
Published: May 2006

Stock SL Pinkster (1970) erected two subspecies of Gammarus duebeni primarily on the basis of a difference in the relative dimensions of the merus on the fifth walking leg. The diagnostic feature was given as the ratio of merus length/width, with ratio < 2 in G. duebeni duebeni and ratio > 2 in G. duebeni celticus. It is shown here that the ratio varies with the size of the animal, and this particular ratio is therefore not valid as a taxonomic character.

Regressions of log merus width on log merus length were made on large samples of G. duebeni assumed to belong to subspecies celticus and duebeni respectively. The regressions were significantly diiferent and were used to predict that the ratio log merus width/log merus length is relatively constant in both subspecies. Diagnostic values for this ratio were 0.71–0.73 in celticus and 0.74–0.77 in duebeni. The ratio was also determined in small samples of G. duebeni from other localities in western Britain.

The morphological difference which characterizes celticus and duebeni was not associated with habitat salinity or with previously determined physiological characteristics. It may be an instance of cHnal variation reinforced by geographical isolation.

Regressions of merus length against cephalic length suggest that the relative growth rates of the merus may also differ in the two subspecies.
Assessment of two mesh sizes for interpreting life cycles, standing crop, and percentage composition of stream insects
Authors: ZELT KENNETH A. , CLIFFORD HUGH F.
Published: May 2006

Using Surber‐type samplers and dip‐net samplers, we assessed the efficiency of nets having pore sizes of 720 μm and 320 μm for determining standing crop and percentage composition of the stream fauna, and for collecting representative size‐class specimens of Ephemeroptera and Plecoptera to be used in life‐cycle studies. Except for one species, samples collected with either the 720‐μm or 320‐μm dip‐net led to the same general inferences about the species' life cycle. Of fifty possible sample comparisons, there were twelve samples where the size‐class frequencies of particular species collected in the 720‐μm dip‐net were significantly different from the size‐class frequencies of the 320‐μm dip‐net; for five of these samples a deficit of large nymphs (> 5.0 mm) in the 320‐μm net mainly contributed to the significant χ2 values. On one date, we used double‐bag samplers with both th e 720‐μm and 320‐μm nets attached to either the Surber or dip‐net sampler. Approximately 50% of the insects by numbers passed through the 720 fxm mesh ofeach sampler, but only 5% by volume‐biomass. Shape of the insect as well as body length was important in assessing mesh‐size efficiencies. The 720‐μm mesh of the double‐bag dip‐net sampler retained most of the Nemoura dnctipes (having stout appendages) and Epeorus longimanus (flattened) nymphs 2.0 mm in body length and larger; whereas most Baetis (streamlined) nymphs smaller than 3.0 mm and all Paraleuctra (needle‐like shape) nymphs passed through the 720‐μm mesh.
The life cycles of Leptophlebia vespertina (L.) and L. marginata (L.) (Ephemeroptera) in Llyn Dinas, North Wales
Authors: BRITTAIN J. E.
Published: May 2006

Data is presented on the life cycles of Leptopblehia vespertina (L.) and L. marginata (L.) in Llyn Dinas, an oligotrophic North Wales lake. Both species are univoltine and growth continues throughout the winter although somewhat retarded. Except during July and August there is a clear size separation of the two species, L. marginata being larger and emerging earlier. The egg incubation period was determined directly from laboratory studies. The results are discussed in relation to previous research in the English Lake District.
A simple portable field nephelometer
Authors: MOORE W. H.
Published: May 2006

A portable field nephelometer is described, capable of indicating in situ differing layers of suspended material in a body of water to a depth of 30 m. Results were compared with those from a standard transparency meter, and a laboratory nephelo‐meter.
Studies on Gull Lake, Michigan
Authors: MOSS BRIAN
Published: May 2006

The seasonal and depth distribution of phytoplankton in Gull Lake, a moderately large, temperate, dimictic, recreational lake in southern Michigan, U.S.A., is described and discussed. Diatoms (Fragilaria crotonensis, Cyclotella michiganiana, Asterionella formosa, and Synechococcus) grow mainly in summer. Diatoms grew under the winter ice, and objections are lodged to the classic explanation of seasonal growth in temperate lakes, and to a recent hypothesis concerning the `paradox of the plankton'. Two raphe‐bearing large diatom species were considered to be truly planktonic. A Synechococcus species was similar to that described previously only from Loch Leven.
A relative growth index of hybridization in sunfishes (genus Lepomis, Centrarchidae)
Authors: MISRA R. K. , HOLDSWORTH C.
Published: May 2006

Sunfish specimens (genus Lepomis) collected from Pinehurst Lake, Ontario, Canada, were identified as bluegill (L. macrochirus), pumpkinseed (L. gibbosus) and their hybrids. Hybridization was studied on the basis of the constants of cross‐sectional allometry as, to the best of our knowledge, no attempt has ever been made to study hybridization quantitatively from the relative growth aspect. Two sets of data‐‐‐one on the pair Y1/X (head length/standard length) and the other on the pair Y2/X (body depth/standard length)‐‐‐ were analysed, with the following objectives: (i)A statistical method of analysing hybrid index based on cross‐sectional allometry was first presented and then Y1/X‐data analysed by this method, and (ii)data Y2/X were analysed to show that in some particular situations analysis for hybridization by methods other than the hybrid index appraoch may be more appropriate. Results of the analyses were discussed.
Further studies on the occurrence of freshwater Microturbellaria in the British Isles
Authors: YOUNG JOHNSTONE O.
Published: May 2006

Five new British records of freshwater Microturbellaria are illustrated: Gieysztoria infundibuliformis, Castrada lanceola, Castrada neocomensis, Castrada viridis and Strongylostoma elongatum. These species together with a new species, Macrostomum johni described by Young (1972), are woven into the fabric of the existing key for the group (Young, 1970). All six species were recorded from the littoral zone of lakes in Caernarvonshire, N. Wales. The times of the recordings are indicated.
Effects of the herbicide paraquat on the ecology of a reservoir
Authors: BROOKER M. P. , EDWARDS R. W.
Published: May 2006

The application of paraquat (1.0 mg/l) to a fishing reservoir was successful in controlling the angiosperms, Potamogeton pectinatus and Myriophyllum spicatum, but a second application (0.6 mg/l) failed to control a replacement growth of the macro‐phytic alga, Chara globularis.

Paraquat was quickly lost from the water after each application and was largely taken up by the sediments, never more than 6% ofthe initial dose being recorded from the macrophytes. Final analysis of the sediments indicated that about 36% of the total amount of paraquat applied to the reservoir was not recovered.

Some changes in the chemistry ofthe water after the first application of paraquat were consistent with the death of the plants (e.g. alkalinity), but there was no evidence that the subsequent decay ofthe plants produced large increases in the concentrations of major nutrients in the water. Although there was no gross deoxygenation there were changes in the oxygen status of the water following the herbicide‐induced death ofthe angiosperms.

Estimates of the biomass and net productivity of the macrophytes were made.
The biology and life cycle of Nemoura avicularis Morton (Plecoptera)
Authors: BRITTAIN JOHN E.
Published: May 2006

Data are presented on the biology and life cycle of Nemoura avicularis Morton in a North Wales lake, Llyn Dinas, and in the laboratory. Aspects of egg, nymphal and adult biology are described and discussed. Special attention is given to the early instars. The life cycle in the field was followed for a 2‐year period. Eggs hatched during April, May and the first half of June, and growth then continued more or less continuously until late January when the nymphs were fully grown. Emergence, however, did not begin until March, reaching a peak in April and continuing into the early part of May. In the laboratory N avicularis was reared through its life cycle from egg to adult. The results of the present study are discussed in relation to previous research on the biology and life cycle of N. avicularis.
Studies on mountain streams in the English Lake District
Authors: SUTCLIFFE D. W. , CARRICK T. R.
Published: May 2006

Comparisons are made of pH and the concentrations of major ions in streamwater from Brownrigg Well (the source of Whelpside Ghyll) and from the River Duddon. pH in Brownrigg Well is usually >5.7, but the concentrations of sodium, potassium and possibly calcium are near to the minima required to support the amphipod Gammarus pulex. In contrast most insect taxa are not affected by low ionic concentrations. It is postulated that these had a wider distribution in mountain streams prior to the acidification of poorly buffered waters by acid rainfall resulting from large‐scale combustion of fossil fuels.
Numerical indices applied to the results of a survey of the macro‐invertebrate fauna ofthe Tamar catchment (southwest England)
Authors: NUTTALL P.M. , PURVES J.B.
Published: May 2006

A survey ofthe macro‐invertebrate fauna in the River Tamar revealed that a division ofthe catchment can be made which separates an organically enriched upper region from a more stable environment in the lower tributaries and reaches. Invertebrate species normally associated with organic pollution were found immediately downstream from farm waste and sewage effluent outfalls. Invertebrate species normally associated with an unpolluted condition were widely distributed throughout the catchment, and revealed that the Tamar is essentially free from gross pollution causing the continuous elimination of stream fauna. Systems used by pollution control organizations to codify biological results are reviewed and applied comparatively to the results. The Diversity index was found to be the most consistent method in assessing the biological state of the river. The Trent, Lothian, Chandler and Carpenter indices were found to give either anomalous figures or proved insensitive to conditions beyond a certain quality.