bluuebunny/crossref_metadata_2025 huggingface dataset:
From fine art to visual culture: assessment and the changing role of art education
Authors: Doug Boughton
Published: May 2006

The influence of digital technology in recent decades has affected all aspects of ordinary visual experience through rapid reproduction and communication of images ultimately contributing to a massive increase in the exposure of children to popular culture. The nature of the fine arts
has also changed in response to the impact of digital technology and the pervasive influence of popular imagery and this has, in turn, affected the ways in which culture is represented. This article discusses ways in which art education is responding to these changes with specific attention
to the relationship of curriculum and assessment. Appropriate portfolio assessment strategies intimately related to curriculum content are described with reference to specific student work
Women: as ‘invisible’ as ever in Nigeria’s news media
Authors: Okunna Chinyere Stella
Published: May 2006

The gender inequality in Nigerian society is reflected in men’srepresentations of women in the news media. Research evidence continues to show that women as journalists are still largely ‘invisible’ in the Nigerian press because the overwhelming majority of people
who report the news are men. Monitoring of the Nigerian press1 shows that very few of the bylines in the news pages belong to women. Thus, the power to define the media agenda in Nigeria is still mainly a male privilege.
The Internet as public sphere or culture industry? From pessimism to hope and back
Authors: Dahlberg Lincoln
Published: May 2006

The vision of communication systems supporting public sphere(s) of discursive contestation has in recent times been embraced by many critical theorists as the ideal democratic role for the media. However, there has also been much pessimism about the realization of this vision. This
pessimism extends from ‘big brother’ fears to hyperrealist scenarios - from the development of a global surveillance society to the implosion of reality in an electronically generated and sustained system of pure fabrication.
Neopian economics of play: children's cyberpets and online communities as immersive advertising in NeoPets.com
Authors: Grimes Sara M. , Shade Leslie Regan
Published: May 2006

This article examines NeoPets, an online community for children where members create or adopt a virtual pet. The NeoPets Corporation is examined, with attention paid to their practice of ‘immersive advertising’ amidst concerns over the increasing commercialization and branding of children's web-based content and culture. Ethical issues explored include privacy and intellectual property.
Regulation of acrosome reaction of fowl spermatozoa: evidence for the involvement of protein kinase C and protein phosphatase-type 1 and/or -type 2A
Authors: Ashizawa K , Wishart G J , Katayama S , Takano D , Ranasinghe A R A H , Narumi K , Tsuzuki Y
Published: May 2006

The signal transduction pathways involved in the regulation of the acrosome reaction and motility of fowl spermatozoa were investigated. The motility and acrosomal integrity of fowl spermatozoa in TES/NaCl buffer, with or without homogenised inner perivitelline layers (IPVL), prepared from laid fowl eggs, was almost negligible at 40 °C. In the presence of 2 mmol CaCl2/l at 40 °C, motility became vigorous and the acrosome reaction was stimulated when IPVL was added. In the absence of Ca2+, motility was stimulated by the addition of calyculin A and okadaic acid, both specific inhibitors of protein phosphatase-type 1 (PP1) and -type 2A (PP2A), but Okadaic acid, which is a weaker inhibitor of PP1, did not completely restore motility at 40 °C. However, the acrosome reaction was significantly and equally stimulated in a dose-dependent manner by both inhibitors in the range of 10–1000 nmol/l, when spermatozoa were incubated with IPVL but without Ca2+. These inhibitors did not stimulate the acrosome reaction in the absence of IPVL. The vigorous motility of spermatozoa, stimulated by the addition of Ca2+, was reduced gradually as the concentrations of SC-9, a selective activator of protein kinase C (PKC), were increased and a similar SC-9-induced inhibition was observed in the acrosome reaction in the presence of Ca2+ and IPVL. These results confirm that IPVL is necessary for the activation of the acrosome reaction in fowl spermatozoa and that Ca2+ plays an important role in the stimulation of motility and acrosomal exocytosis. Furthermore, it appears that the intracellular molecular mechanisms for the regulation of acrosome reaction of fowl spermatozoa are different from those for the restoration of motility, i.e., protein dephosporylation involving PP1 and/or PP2A in the former, and PP1 alone in the latter case. In addition, the activation of PKC may contribute to a decrease in the flagellar movement and acrosome reaction of fowl spermatozoa.
Expression and regulation of stanniocalcin 1 and 2 in rat uterus during embryo implantation and decidualization
Authors: Xiao Li-Juan , Yuan Jin-Xiang , Song Xin-Xin , Li Yin-Chuan , Hu Zhao-Yuan , Liu Yi-Xun
Published: May 2006

Stanniocalcin-1 (STC-1) is a recently discovered polypeptide hormone, while stanniocalcin-2 (STC-2) is a subsequently identified homologue of stanniocalcin-1. Although previous studies have shown that both STC-1 and -2 are involved in various physiological processes, such as ion transport, reproduction and development, their expression in the uterus and roles in implantation and early pregnancy are unclear. Here we have investigated the expression and regulation of both STC-1 and STC-2 in rat uterus during early pregnancy under various physiological conditions. We show that only basal levels of STC-1 and STC-2 mRNA were detected in the uterus from day one (D1) to day five (D5) of pregnancy. STC-2 immunostaining was gradually increased in the glandular epithelium from day two (D2), with a peak occurring on D5. High levels of both STC-1 and STC-2 mRNA were observed in the stoma cells at the implantation site on day six (D6) of pregnancy, whereas their immunostaining signals were also significant in the luminal epithelium. Basal levels of both STC-1 and STC-2 mRNA and STC-1 immunostaining were detected in the uterus with delayed implantation. After the delayed implantation was terminated by estrogen treatment, both STC-1 and STC-2 mRNA signals were significantly induced in the stroma underlying the luminal epithelium at the implantation site, and STC-2 immunostaining was also observed in the luminal epithelium surrounding the implanting blastocyst. Embryo transfer experiments further confirmed that STC-1 and STC-2 expression at the implantation sites was induced by the implanting blastocyst. Both STC-1 mRNA and immunostaining were seen in the decidualized cells from day seven (D7) to day nine (D9) of pregnancy. STC-2 mRNA was also found in the whole decidua from D7 to D9 of pregnancy; STC-2 protein, however, was strictly localized to the primary deciduas on D7 and D8, with a weak expression in the whole deciduas on D9. Consistent with the normal pregnancy process, strong STC-1 and STC-2 mRNA signals were detected in the decidualized cells under artificial decidualization, whereas only basal levels of STC-1 mRNA and immunostaining were observed in the control horn. These data suggest, for the first time, that STC-1 together with STC-2 may play important roles in the processes of implantation and decidualization in the rat.
Germ cell development in equine testis tissue xenografted into mice
Authors: Rathi R , Honaramooz A , Zeng W , Turner R , Dobrinski I
Published: May 2006

Grafting of testis tissue from immature animals to immunodeficient mice results in complete spermatogenesis, albeit with varying efficiency in different species. The objectives of this study were to investigate if grafting of horse testis tissue would result in spermatogenesis, and to assess the effect of exogenous gonadotropins on xenograft development. Small fragments of testis tissue from 7 colts (2 week to 4 years of age) were grafted under the back skin of castrated male immunodeficient mice. For 2 donor animals, half of the mice were treated with gonadotropins. Xenografts were analyzed at 4 and 8 months post-transplantation. Spermatogenic differentiation following grafting ranged from no differentiation to progression through meiosis with appearance of haploid cells. Administration of exogenous gonadotropins appeared to support post-meiotic differentiation. For more mature donor testis samples where spermatogenesis had progressed into or through meiosis, after grafting an initial loss of differentiated germ cells was observed followed by a resurgence of spermatogenesis. However, if haploid cells had been present prior to grafting, spermatogenesis did not progress beyond meiotic division. In all host mice with spermatogenic differentiation in grafts, increased weight of the seminal vesicles compared to castrated mice showed that xenografts were releasing testosterone. These results indicate that horse spermatogenesis occurs in a mouse host albeit with low efficiency. In most cases, spermatogenesis arrested at meiosis. The underlying mechanisms of this spermatogenic arrest require further investigation.
Fertility Preservation in Young Women Undergoing Breast Cancer Therapy
Authors: Sonmezer Murat , Oktay Kutluk
Published: May 2006

Learning Objectives

After completing this course, the reader will be able to: Explain how chemotherapy for breast cancer impacts ovarian function.Discuss the incidence of ovarian failure after chemotherapy and list the chemotherapeutic agents most likely to cause loss of fertility in breast cancer patients.Describe options for fertility preservation in women undergoing breast cancer therapy.

Access and take the CME test online and receive 1 AMA PRA category 1 credit at CME.TheOncologist.com

Breast cancer accounts for one third of all neoplasms seen in reproductive-age women and affects tens of thousands of women each year in that age group. The adjuvant chemotherapy regimens used for the treatment commonly affect fertility and cause premature ovarian failure. There have been recent advances in the field of fertility preservation, which can allow many of these breast cancer survivors to have children in the future. The most established option is embryo cryopreservation; oocyte cryopreservation can be considered in single women. Both of these approaches require approximately 2 weeks of ovarian stimulation beginning with the onset of the patient's menstrual cycle. Thus, it is crucial that these patients are referred to appropriate assisted reproduction centers as soon as they are diagnosed with breast cancer. Recently developed ovarian stimulation protocols using tamoxifen and letrozole can be used to increase the margin of safety in these patients. When and if a breast cancer patient does not have time to undergo ovarian stimulation prior to chemotherapy, ovarian cryopreservation for future autotransplantation can be offered as the last resort. The benefit of ovarian protection by gonadotropin-releasing hormone analogues is unproven and unlikely, and thus this treatment should not be offered as the sole method of fertility preservation.
Preventing Chemotherapy Errors
Authors: Schulmeister Lisa
Published: May 2006

Learning Objectives

After completing this course, the reader will be able to: Define the extent and scope of chemotherapy errors and their impact on patient care.Describe common types of prescribing errors.Recommend procedures to prevent errors in drug orders, preparation, and identification of patients.Identify reporting and monitoring systems both within your institution and at the government levels.

Access and take the CME test online and receive 1 AMA PRA category 1 credit at CME.TheOncologist.com

A large amount of information on chemotherapy error prevention is available to the practicing oncologist. However, few oncologists have the time and resources to obtain the information and evaluate the evidence. Further, much of the information is generic and does not provide specific direction on how the information can be applied in clinical practice. This manuscript reviews principles of safe chemotherapy administration, identifies key actions to prevent chemotherapy errors, and provides suggestions on how the information can be incorporated into daily practice.
Teams: Communication in Multidisciplinary Care
Authors: Penson Richard T. , Kyriakou Helena , Zuckerman Dan , Chabner Bruce A. , Lynch Thomas J.
Published: May 2006

Learning Objectives

After completing this course, the reader will be able to: Describe the roles of teams in multidisciplinary cancer care.Discuss the strengths, weaknesses, and opportunities of team-based care.Describe the historical and cultural context of modern medical team-based care.

Access and take the CME test online and receive 1 AMA PRA category 1 credit at CME.TheOncologist.com

Shortly before his death in 1995, Kenneth B. Schwartz, a cancer patient at Massachusetts General Hospital (MGH), founded The Kenneth B. Schwartz Center at MGH. The Schwartz Center is a nonprofit organization dedicated to supporting and advancing compassionate health care delivery that provides hope to the patient and support to caregivers, and encourages the healing process. The Center sponsors the Schwartz Center Rounds, a monthly multidisciplinary forum where caregivers reflect on important psychosocial issues faced by patients, their families, and their caregivers, and gain insight and support from fellow staff members.

The evolving field of oncology increasingly requires a team of medical specialists working in unison to deliver optimal medical care. While this coordination may maximize the technical synergy of care, it can challenge interprofessional and interdisciplinary connections. Poor and miscommunication and conflicts between staff and between the family and providers adversely affect patient care and quality of life. Furthermore, lack of communication leaves a vacuum that sucks in fear. A recent Newsweek article highlighted the challenges of practicing in the age of high-tech medicine. The author had to beg for a prognosis for her critically ill and dying husband, with unhelpful subspecialists failing to communicate the bigger picture. This article explores the tough issue of how teams handle uncertainty and bad news and how patients and families can be better supported in the multifaceted paradigm of modern care.
Cycling and early pregnant endometrium as a site of regulated expression of the vitamin D system
Authors: Viganò P , Lattuada D , Mangioni S , Ermellino L , Vignali M , Caporizzo E , Panina-Bordignon P , Besozzi M , Di Blasio A M
Published: May 2006

In addition to its calciotropic function, the secosteroid 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), has potent anti-proliferative/immunomodulatory effects on various tissues. Consistently, the enzyme that catalyzes the synthesis of 1,25(OH)2D3, 1α-hydroxylase (1α-OHase) and the vitamin D receptor have a widespread tissue distribution. Among site-specific functions, the hormone has been suggested to be involved in uterine physiology. However, molecular analysis of the vitamin D system in normal endometrium throughout the menstrual cycle as well as its regulation in the context of endometrial physiological and pathological events have received very limited attention. Thus, we have studied expression, localization and regulation of 1α-OHase in human cycling and early pregnant endometrium. The capacity for 1α-hydroxylation and the presence of vitamin D receptor in endometrial cells have also been evaluated. The functional significance of these findings has been tested by evaluating gene expression of the catabolic enzyme, vitamin D 24-hydroxylase, and of the adhesion protein, osteopontin. Finally, to verify any potential dysfunction of the vitamin D system in endometriosis, a reproductive disease characterized by immune-mediated anomalies, we have analyzed expression of 1α-OHase in both eutopic and ectopic endometrium of affected patients. Results obtained showed that the active form of the 1α-OHase gene was expressed in human endometrial stromal cells independent of the cycle phase but with a significant increase in early pregnant decidua. A similar profile was observed for the protein, which was abundantly expressed in the cytoplasm of both endometrial stroma and epithelial glands. Both cycling and early pregnant endometrial cells also expressed the vitamin D receptor. In the same cells, 1α-OHase mRNA levels were significantly stimulated by the pro-inflammatory cytokine interleukin (IL)-1β (50 and 500 pg/ml) while addition of the active form of the hormone could modulate both CYP24 and osteopontin gene expression. The 1α-OHase gene was also expressed in ectopic endometrium and its levels were increased in proliferative phase cultures derived from patients with endometriosis. Human cycling endometrium may be included among the extrarenal sites able to synthesize vitamin D. The IL-1β-mediated induction of 1α-OHase gene and the hormonal modulation of osteopontin support a role for the hormone in the immunological mechanisms underlying uterine function. Abnormalities of this system are present in endometriosis.
Overview of Pharmacogenetics
Authors: Katz David A.
Published: May 2006

Pharmacogenetics is the study of relationships between genetic variation and inter‐individual differences with respect to drug response. As the field has matured over the past 15 years, a remarkable diversity of pathways, variation types, and mechanisms have been found to be relevant pharmacogenetic factors. Today, pharmacogenetics is becoming more important in pharmacology for target validation, lead optimization, and understanding of idiosyncratic toxicity. This unit provides an overview of the history of pharmacogenetics and current research applications in drug discovery, as well as a discussion of research quality issues relevant for human subjects research in the pharmacogenetics laboratory.
Techniques for Mammalian Cell Tissue Culture
Authors: Phelan Mary C.
Published: May 2006

This unit opens with detailed discussions on the latest principles of sterile technique and preparation of culture media. Step‐by‐step protocols describe trypsinizing and subculturing monolayer cultures, passaging suspension cultures, freezing and thawing cells, counting cells using a hemacytometer, and preparing cells for transport.
Diastereoselective Ethynylation of Chiral α‐(Dibenzylamino) Aldehydes: Synthesis of meso‐ and Homochiral C2‐Symmetrical 1,6‐Diamino‐2,5‐diols
Authors: Andrés José M. , Pedrosa Rafael , Pérez‐Encabo Alfonso
Published: May 2006

Homochiral α‐(dibenzylamino) aldehydes, prepared from the corresponding α‐amino acids, react with ethynylmagnesium bromide in THF/Et2O at 0 °C to afford, in good yields and dr, propargylic 1,2‐amino alcohols; anti diastereomers were always formed as the major products in this reaction. These compounds are versatile intermediates in the synthesis of meso‐ and enantiopure 1,6‐diamino‐2,5‐diols with C2 symmetry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Development of a capillary electrophoresis‐mass spectrometry method for the determination of formaldehyde releasers as their hydrolysis products and amino alcohols from metal working fluids
Authors: Fekete Agnes , Hertkorn Norbert , Frommberger Moritz , Lahaniatis Majlinda R. , Kettrup Antonius , Schmitt‐Kopplin Philippe
Published: May 2006

Metal working fluids (MWFs) are widely used as lubricants and coolants for different industrial operations. Biocides are ingredients of MWFs to control the microbial growth; derivatives of hexahydrotriazines and oxazolidines are generally used. Because of the lack of appropriate characterization, an existing capillary electrophoretic method for their quantification was improved. During the process of optimization, it became clear that hydrolysis products, derivatives of amino alcohols, severely interfere with the separation procedure. Since indirect‐UV detection lacked the required selectivity, mass‐selective detection was employed. NMR and MS established the absence of amino alcohols in the original educts. The aqueous solutions of the biocides stored for extended time remained amino alcohol‐free, suggesting that these amino alcohols are formed from the biocides during the capillary electrophoretic separation. The observation of narrow and symmetric peaks indicated hydrolysis, and the polarity of the products implied favorable conditions for capillary electrophoretic separation. Methods were optimized for the analysis of the amino alcohols, the hydrolytic products of the formaldehyde releasers, using indirect‐UV and MS detection. This method was extended to other likely solutes used as alkaline‐reserve ingredients. The analytes were separated within 9 min with a high precision of migration times (the RSDs were below 1.5%). When quantifying from mobility scale, the calibration curves produced linearity with regression coefficients in the range of 0.990–0.999. The detection limit was lower than 1 mg/L in the case of MS detection. The influence of water‐based MWF was also investigated, and no matrix effect on the migration of the analytes and on the peak areas was observed.
The long‐run impact of coups on Fiji's economy: evidence from a computable general equilibrium model
Authors: Narayan Paresh Kumar , Prasad Biman Chand
Published: May 2006

Coups have been used as a weapon to overthrow democratic governments in Fiji since 1987. The post‐1987 period has been one of the most volatile ones in Fiji's history, in that it has undergone 15 changes in government. In this paper, we analyse the long run economy‐wide impact of the May 2000 coup on Fiji's economy. This goal is achieved by using the computable general equilibrium model, which is at the forefront of ‘impact studies’. We find that coups will have an adverse impact on the Fijian economy: real GDP will fall by around 8 per cent, real national welfare will fall by around 7 per cent and real consumption will fall by around 2 per cent in the long‐run. Copyright © 2006 John Wiley & Sons, Ltd.
ABCA1-dependent but apoA-I-independent cholesterol efflux mediated by fatty acid–bile acid conjugates (FABACs)
Authors: Goldiner Ilana , van der Velde Astrid E. , Vandenberghe Kristin E. , van Wijland Michel A. , Halpern Zamir , Gilat Tuvia , Konikoff Fred M. , Veldman Robert Jan , Groen Albert K.
Published: May 2006

FABACs (fatty acid–bile acid conjugates) are synthetic molecules that are designed to treat a range of lipid disorders. The compounds prevent cholesterol gallstone formation and diet-induced fatty liver, and increase reverse cholesterol transport in rodents. The aim of the present study was to investigate the effect of FABACs on cholesterol efflux in human cells. Aramchol (3β-arachidylamido-7α,12α,5β-cholan-24-oic acid) increased cholesterol efflux from human skin fibroblasts in a dose-dependent manner in the absence of known efflux mediators such as apoA-I (apolipoprotein A-I), but had little effect on phospholipid efflux. An LXR (liver X receptor) agonist strongly increased Aramchol-induced cholesterol efflux; however, in ABCA1 (ATP-binding cassette transporter A1)-deficient cells from Tangier disease patients, the Aramchol effect was absent, indicating that activity of ABCA1 was required. Aramchol did not affect ABCA1 expression, but plasma membrane levels of the transporter increased 2-fold. Aramchol is the first small molecule that induces ABCA1-dependent cholesterol efflux without affecting transcriptional control. These findings may explain the beneficial effect of the compound on atherosclerosis.
Is Pigmentation Important for Face Recognition? Evidence from Contrast Negation
Authors: Russell Richard , Sinha Pawan , Biederman Irving , Nederhouser Marissa
Published: May 2006

It is extraordinarily difficult to recognize a face in an image with negated contrast, as in a photographic negative. The variation among faces can be partitioned into two general sources: (a) shape and (b) surface reflectance, here termed ‘pigmentation’. To determine whether negation differentially affects the processing of shape or pigmentation, we made two sets of faces where the individual faces differed only in shape in one set and only in pigmentation in the other. Surprisingly, matching performance was significantly impaired by contrast negation only when the faces varied in pigmentation. This provides evidence that the perception of pigmentation, not shape, is selectively disrupted by negation and, by extension, that pigmentation contributes to the neural representation of face identity.
The upper limit of photosynthetic productivity by phytoplankton: evidence from Ethiopian soda lakes
Authors: TALLING J. F. , WOOD R. B. , PROSSER M. V. , BAXTER R. M.
Published: May 2006

Photosynthetic production by phytoplankton was studied in two Ethiopian soda lakes, alkalinity 51‐67 m‐equiv./l, with abundant blue‐green algae. The deeper lake, L. Aranguadi, contained extremely dense crops composed almost entirely of SpiruUna (Oscillatoria, Arthrospira) platensis. Measurements of the spectral attenuation of light showed that the most penetrating component was displaced to the red spectral region, and estimates of the chlorophyll a content in umt area of the euphotic zone were often similar to the highest values (∼200‐300 mg/m2) expected on theoretical grounds.

The vertical distribution of photosynthetic activity per unit water volume was of a typical pattern for phytoplankton, with light‐inhibition often present, although the euphotic zones did not exceed 0.6 m in depth. From these profiles, computed rates of gross photosynthesis per unit area of lake surface reached a magnitude of 1.4–2.4 g O2/m2.h in both lakes. They were obviously severely limited by self‐shading behaviour i n the algal populations. An appreciable inverse relationship between photosynthetic capacity and population density was only found in the densest populations of L. Aranguadi, with chlorophyll a content > 2000 mg/m3, where depressed rates might result from experimental artefacts in closed bottles. In this lake, two independent estimates of gross production, based on the analysis of diurnal changes in the open water, were as high as 43 and 57 g O2/m2. day.

Diurnal changes of stratification in the two lakes are described and related to the controlling temperature (density) stratification. They include occasionally complete nocturnal deoxygenation in the deeper lake, evidence of heavy respiratory uptake.

The high photosynthetic productivity is interpreted as dependent upon the coupling of high algal contents in the euphotic zone (^S) with high values of photosynthetic capacity (^max)‐ It is probably favoured by the tropical situation affecting temperature and illumination, by a surplus of dissolved inorganic phosphate, and especially by the considerable reserves of carbon dioxide in these soda lakes.
Algal nitrogen fixation in Californian streams: diel cycles and nocturnal fixation
Authors: HORNE ALEXANDER J.
Published: May 2006

Thirty‐six hour diurnal studies of Ng‐fixation by Nostoc in a rocky‐bedded stream were carried out during the peak of the seasonal cycle of growth on clear and cloudy days in 1971 and 1972. On both occasions an unexpected pattern of N2‐fixation occurred with maximum fixation rates in the light but also in the dark portion of the day, with lowest fixation periods in the early evening. I postulate that competition for reductant between nitrogenase and other processes, especially photorespiration, controls this unusual diel cycle rather than variations in the intracellular N‐pool. N2‐fixation rates on a cloudless May day in 1971 ranged from 0.2 to 4.8 nmoles C2H4 cm−2 h−1 and from 0.3 to 3.3 nmoles C2H4 mg−1 h−1 dry weight of Nostoc, depending on time of day and favourableness of site. On the same site on a cloudy, rainy May day in 1972 fixation ranged from 0.5 to 3.1 nmoles C2H4 mg−1 h−1 dry weight, and from 1 to 4.5 nmoles C2H4 mg−1 h−1 ash‐free dry weight of Nostoc. Since Nostoc is most abundant in unshaded areas, and since one‐third of each day's nitrogen i s fixed in the dark, future studies should take dark fixation into account.
A pumping system for collecting horizontal plankton samples and recording continuously sampling depth, water temperature, turbidity and in vivo chlorophyll
Authors: GEORGE D. G.
Published: May 2006

This paper describes a deck‐mounted pumping system developed for collecting discrete, sequential plankton and water samples while also providing a continuous record of sampling depth, water temperature, turbidity and in vivo chlorophyll. It includes some results obtained with the equipment during a study of factors influencing the horizontal distribution of crustacean plankton in the lake Windermere.
Notes on the ecology of fishes of the genus Aphanius and Gambusia affinis in Southern Iraq
Authors: AL‐DAHAM N. K. , HUQ M. F. , SHARMA K. P.
Published: May 2006

SUMMARY. The ecology of three commonly occurring cyprinodonts, Aphanius dispar (Ruppell), A. sophiae (Heckel) and A. mento (Heckel) was studied in the Lower Mesopotamian Plain of Iraq. These fishes are chiefly herbivorous, live in the same habitat and generally take the same food, although the dentition of the jaw and pharynx in A. dispar differs from that of A. mento and A. sophiae. The gut contents were mostly filamentous algae. In laboratory experiments all three species ate Gambusia embryos. A. dispar and A. sophiae ate mosquito larvae whereas A. mento did not. All three species were infected with a cestode parasite which prevented development of female ovaries. The behaviour of the three species was different. Both A. dispar and A. sophiae form schools, swimming and feeding together. In their natural habitat, males and females of A. dispar were in separate schools. A. mento did not form schools; the males of this species displayed aggressive behaviour. Some observations were also made on Gambusia affinis (Baird & Girard).
The food and feeding habits of young perch, Perca fluviatilis, in Windermere
Authors: GUMA'A S. A.
Published: May 2006

SUMMARY.
The food of 0+ perch, Perca fluviatilis L. has been investigated in Windermere, the largest lake in the English Lake District. Whole guts and stomachs from 800 fish were investigated during four 24‐h periods between June and September in 1975 and in 1976. Ciliates, algae, rotifers and cyclopoid nauplii constituted the first food of larval perch in Windermere. Vertical samples were taken from the zooplankton, at the same time and in the same location where the fish were sampled, and the concentration of the different food organisms studied. Electivity of the different food organisms was studied from lvlev's index, which showed positive electivity, or selection for some organisms, e.g. Bosmina obtusirostris (Sars.) and copepods (both cyclopoid and calanoid), and negative for others such as Daphnia hyalina var. galeata (Sars.), Leptodora kindti (Focke) and Bythotrephes longimanus (Leydig). In studying predatorprey relationships, Daphnia hyalina was chosen as the ‘standard prey’, being the most abundant of all food organisms in the diet of young perch, also because its maximum body‐depth (carapace width (mm)) was among the largest of the cladocera and copepods in Windermere. Comparison of the maximum carapace width of Daphnia eaten with that of the plankton revealed that smaller specimens were taken by juvenile perch in July, but they tended to select larger organisms during August and September.
The rate of colonization by macro‐invertebrates on artificial substrate samplers
Authors: MEIER PETER G. , PENROSE DAVID L. , POLAK LOREN
Published: May 2006

SUMMARY.
The influence of exposure time upon macro‐invertebrate colonization on modified Hester‐Dendy substrate samplers was investigated over a 60‐day period. The duration of exposure affected the number of individuals, taxa and community diversity.

The numbers of individuals colonizing the samplers reached a maximum after 39 days and then began to decrease, due to the emergence of adult insects. Coefficients of variation for the four replicate samples retrieved each sampling day fluctuated extensively throughout the study. No tendencies toward increasing or decreasing coefficients of variation were noted with increasing time of sampler exposure.

The number of taxa colonizing the samplers increased throughout the study period. The community diversity index was calculated for each sampling day and this function tended to increase throughout the same period. This supports the hypothesis that an exposure period of 6 weeks, as recommended by the United States Environmental Protection Agency, may not always provide adequate opportunity for a truly representative community of macro‐invertebrates to colonize multiplate samplers.

Many of the taxa were collected in quite substantial proportions after periods of absence or extreme sparseness. This is attributed to the growth of periphyton and the collection of other materials that created food and new habitats suitable for the colonization of new taxa.

Investigation of the relationship between ‘equitability’ and length of exposure revealed that equitability did not vary like diversity with increased time of exposure.
Acidity and species diversity in freshwater crustacean faunas
Authors: FRYER GEOFFREY
Published: May 2006

SUMMARY.
On the basis of material from over seventy acidic water bodies in three different areas a relationship is revealed between pH and the species diversity of their crustacean faunas. With increasing acidity species diversity decreases. No such relationship is shown between calcium concentration and species diversity. The very low calcium levels of such waters may, however, play a part in the exclusion of certain species.
A new sampler for stream benthos, epiphytic macrofauna and aquatic macrophytes
Authors: HILEY P. D. , WRIGHT J. F. , BERRIE A. D.
Published: May 2006

SUMMARY.
A new sampler is described combining the advantages of both box and Surber samplers. The sample area is 200 × 250 mm (0.05 m2) and the device has been used to sample the benthos of rivers to a depth of c. 60 mm where the substratum consists of particles with diameters of 50 mm or less. The basic design may be used in water up to 0.5 m in depth, but with an optional top unit this depth may be increased to 1 m. Aquatic macrophytes can also be sampled either on their own or together with the underlying substratum. Results from sampling programmes designed to estimate macrophyte biomass, the biomass of the macroinvertebrate community and the density of Gammarus pulex are given as examples of the flexibility of the sampler on a variety of biotopes.
Growth and production of five species of Ephemeroptera larvae from an experimental recirculating stream
Authors: WELTON J. S. , LADLE M. , BASS J. A. B.
Published: May 2006

SUMMARY. The production and growth of the larvae of five species of Ephemeroptera in an experimental recirculating stream‐channel are described. The most abundant species were Baetis rhodani, which achieved a maximum population density of c. 29,000 m‐2 in August, and Ephemerella ignita which reached a density of c. 13,000 m‐2 in the spring. Three other common speeies, Paraleptophlebia submarginata, Centroptilum luteolum and Caenis rivulorum were present at lower densities (< 1000 m‐2). B. rhodani had five cohorts in a year whilst C. luteolum had two or possibly three. E. ignita, C. rivulorum and P. submarginata were univoltine. Mean speeifie growth rates were calculated for each species, the maximum being 3.26±0.49% length day‐1 for E. ignita (3 April—15 May). Production of each of these five species of Ephemeroptera was calculated giving a total annual production of 10.2 g dry wt m‐2 (computational method).
Energetics of a population of Asellus aquaticus (Crustacea, Isopoda): respiration and energy budgets
Authors: ADCOCK J. A.
Published: May 2006

SUMMARY. Respiration of Asellus aquaticus was determined on tiine occasions throughout the year using a Gilson differential respirometer. On each occasion the determination was made at the lake temperature, which ranged from 2 to 18°C, Linear regressions were derived for log oxygen uptake against log dry weight. There was a significant difference between mean rates of oxygen uptake at the various temperatures but the slopes of the regression lines, which varied from 0,62 to O.85 with a mean of 0,76, were not significantly different.

The temperature of the lake was monitored throughout the year. Using the relationship of oxygen uptake against temperature, and estimates of population density obtained previously, the total annual respiration of the population was calculated as 4571 ml O2 m‐2, equivalent to an energy loss of 92.3 kj m‐2 year‐1 from a mean biomassof 752 mg m‐2.

Consumption of decayed Alnus glutinosa leaves and faecal production rates, and thus assimilation efficiency, were determined by gravimetric methods in the laboratory at 10°C, close to the mean temperature of the lake (10.rC), In the four size classes investigated, larger animals consumed more food per individual, but less on a weight specific basis. However, it was shown that consumption was greater if the leaf material was more highly decomposed, Assimiliation efficiency was calculated as 23%.

Using data for respiration, population density and the assimilation efficiency, the annual population energy budget was estimated as (kJ m‐2year‐1): consumption, 568.9 (100%); production, 38.5 (6.8%); respiration, 92.3 (16.2%); faeces, 438.1 (77%). The significance of these energy values, and the ecological efficiencies calculated from them, are discussed in relation to other published work.
Long‐term and seasonal changes in the chemical composition of precipitation and surface waters of lakes and tarns in the English Lake District
Authors: SUTCLIFFE D. W. , CARRICK T. R. , HERON J. , RIGG E. , TALLING J. F. , WOOF C. , LUND J. W. G.
Published: May 2006

SUMMARY. The composition of bulk (wet and dry) precipitation in 1975 and 1976 was similar to that found 22 years previously. In 1975, mean values for nine precipitation samplers at one site (Wraymires) ranged from pH 4.3 to 4.5; similar values were obtained in 1976. Samplers covered with fine‐mesh plastic gauze caught substantially more Ca2+ and K+ than open samplers, but pH and SO2‐4+ NO3‐ concentrations were similar in open and covered samplers. In precipitation, c. 50% of H+ was balanced by NO3‐ and c. 50% by SOi; 80% of the SO2‐4 was balanced by Ca2+ and Mg2+.

Conccntrations of major cations (H+, Na+, K+,Ca2+, Mg2+) and anions (CI‐, NO3‐ SO2‐4 and alkalinity [Alk—largely HCO3‐]) in upland water‐ bodies were similar to those found in precipitation, but pH levels were generally higher and above 6.0 m some tarns. At lower altitudes, on base‐rich roeks and soils, Ca2+ and Alk become dominant. Results of a survey of lakes and tarns in 1974–78 are compared with a survey in 1953–56 and published data (chiefly for pH and Alk) for 1947–50, 1932 and 1928. Comparisons are also made with other measurements of Alk in three productive lakes (Blelham Tarn, Esthwaite Water and Windermere) for 1936–39 and 1945–80. Winter levels of NO3‐N, PO4‐P and Si are given for these lakes; although the first two have increased during the late 1960s and the 1970s there has been no significant change in the last. NO3‐ and probably some SO2‐4. In productive lakes a substantial (c. 50%) rise in mean Alk occurred during the late 1960s and the 1970s, possibly related to increased winter levels of NO3‐N and PO4‐P derived from sewage and fertilizers. In this period the maximum pH levels reached in summer were notably high, sometimes exceeding pH 10. The rise in Alk, conductivity and pH of surface waters is influenced by climatic factors (a decade of drier years), sewage input and biological productivity within the lakes.

Considerable seasonal fluctuations in the concentrations of major ions, a characteristic feature of surface waters in the English Lake District, are illustrated and some implications for cation‐anion balance briefly discussed. Mid‐winter concentrations are usually high forNa+, K+, Cl‐. NO3‐and low for Ca2+, Mg2+, Alk. SO2‐4.

Alkalinity. pH and conductivity of Lake District tarns and lakes show no signs of acidification during the period 1928–80. On the contrary, productive lakes have become more alkaline and some unproductive low‐alkalinity (< 100 μ‐equiv. 1‐1) lakes also show signs of alkalization, with increased mean concentrations of Na+. Ca2+ and Mg2+, balanced by Alk.
A model relating the results of low pH bioassay experiments to the fishery status of Norwegian lakes
Authors: SADLER K.
Published: May 2006

SUMMARY. 1. Data from the literature concerning several Norwegian brown trout (Salmo trutta) populations are used to construct Leslie matrices in order to estimate their capacity to withstand egg and fry mortalities. These estimates are compared with the results of bioassay studies conducted at pH 4.5 and at various calcium concentrations in order to predict the percentage of trout populations which would be able to survive these conditions.

2. These predictions are in good agreement with the observed fishery status of Norwegian lakes at calcium concentrations <30 /μeq I−1 but above this concentration the recorded status is worse than predicted.

3. Likely causes for this difference are considered to be effects acting on fish older than those used in the bioassay experiments (either mortality or reduction in fecundity possibly due to impaired growth) or the effects of other water quality factors, for example aluminium.

4. These effects need only be fairly slow acting as compared with the egg and fry mortalities so far studied in detail. Thus the discrepancy between predicted and observed results at pH 4.5 and 50μeq 1‐−1 calcium could be caused by an additional 80% mortality acting over the 4–8 year period before maturation.

5. An additional factor which could result in the observed fishery status being worse than predicted is temporal variation in water chemistry which is not assessed in the survey of Norwegian lakes. In particular, the adverse conditions occurring at time of snowmelt could be critically important.
On the habitats of three species of the genus Hygrotus Stephens (Coleoptera: Dytiscidae)
Authors: CUPPEN J. G. M.
Published: May 2006

SUMMARY. 1. Adult Hygrotus beetles were collected from about 400 localities out of 621 sampled in the Netherlands. Distribution of the three Dutch species of this genus has been related to different environmental variables, principally by use of the Index of Representation (I.R.).

2. Hygrotus decoratus is an acidophilous and haloxenous species. It inhabits small water bodies such as peat‐ditches, reed‐lands and overgrown ditches where emergent plants are abundant. Hygrotus inaequalis occurs in all of the habitats studied and has no clear preferences or aversions with respect to the environmental variables examined. Hygrotus versicolor inhabits permanent water bodies such as clay‐ and sand‐canals which have a rich growth of submerged plants and a weak current. The species has a significant preference for waters with a pH between 7.1 and 8.0 and a chlorinity between 60 and 200 mg 1‐−1.

3. H. decoratus and H. versicolor rarely co‐exist because of their different environmental requirements, but both species often co‐exist with H. inaequalis. Structural environmental variables such as water depth and abundance and growth‐form of the aquatic plants play a greater role than chemical factors in habitat selection by Hygrotus spp.
The formation, structure and utilization of stone surface organic layers in two New Zealand streams
Authors: ROUNICK J. S. , WINTERBOURN M. J.
Published: May 2006

SUMMARY.

 The development of stone surface organic layers was investigated in dark and light experimental channels at two field sites. Layer formation was monitored by measuring organic carbon, chlorophyll‐a, ATP and rates of oxygen consumption, and using scanning electron microscopy.

 In the darkened forest stream channel an organic layer consisting of slime, fine particles, bacteria and fungi developed and attained maximum biomass (=0.08 mg cm‐2) in about 2 months. At the second site, channels were fed by spring water low in dissolved and particulate organic matter (DOC < 0.5 g m‐3) and no organic layer developed on stones in the dark. Organic layers grown in channels subject to natural light intensities and photoperiods were dominated by diatoms and/or filamentous algae at both sites.

 Laboratory experiments carried out in enclosed, recirculating stream channels demonstrated the importance of dissolved organic matter (DOM) as a prerequisite for layer formation. Also. DOM additions in the form of leaf leachates stimulated oxygen consumption by preformed layers. Uptake by microorganisms accounted for most of the reduction in water‐column DOM.

 Radiotracer experiments (14C and 144Ce) showed that several common stream invertebrates could feed on ‘heterotrophic’ layers. Calculated assimilation efficiencies ranged from 18% to 74% and imply that nonautotrophic components of stone surface organic layers are likely to play a significant role in carbon transfer to the benthos, particularly in small, shaded streams.
Diel food habits of two species of setipalpian stoneflies (Plecoptera) in tributaries of the Clearwater River, Idaho
Authors: JOHNSON JAMES H.
Published: May 2006

SUMMARY. The foreguts of two setipalpian stonefly nymphs, Skwala parallela and Hesperoperla pacifica, from tributaries of the Clearwater River, Idaho, were examined in terms of composition and fullness. A total of 736 nymphs were collected at 06.00,12.00,18.00 and 24.00 hours during a 1‐week period in August in order to examine diel variation in both diet composition and feeding periodicity. Substantial diel variation in diet composition and Electivity Indices (E) occurred. No single prey taxon was consistently the principal component in the diet of either stonefly species during all 6‐h sampling intervals. Overall, hydropsychids (15.3–60.6%) were the major food of H. pacifica in Mission Creek whereas chironomid larvae were the chief prey of S. parallela in Mission (10.0–47.2%) and Lapwai (14.9–28.0%) Creeks. Nymphs were nocturnal feeders with feeding increasing from 18.00 to 06.00 hours and with peak feeding occurring from 24.00 to 06.00 hours.
The behavioural basis of prey selection by underyearling bream (Abramis brama (L.)) and roach (Rutilus rutilus (L.))
Authors: WINFIELD IAN J. , PEIRSON GRAEME , CRYER MARTIN , TOWNSEND COLIN R.
Published: May 2006

SUMMARY. A clear difference in the ability lo escape from fish predators exists between members of the Cladocera and Copepoda. The results of our laboratory studies have shown that underyearling roach and bream both found copepods more difficult to capture than cladocerans. However, bream were far more efficient than roach at catching the more elusive copepod prey. The basis for this difference was the greater strike ability of bream, most likely related to its more protrusible mouth. In their natural environment the two species of fish exhibited food resource partitioning with planktonic Cladocera predominating in roach guts and copepods and non‐planktonic Cladocera composing the vast majority of the gut contents of bream. Differences in diet are partly due to their contrasting attack abilities. Additional variation may arise because of subtle differences in the timing and location of foraging.