bluuebunny/crossref_metadata_2025 huggingface dataset:
PARENTING PROGRAMMES: Do generalist parenting programmes improve children's behaviour and attendance at school? The parents’ perspective
Authors: Rogers Lynne , Hallam Susan , Shaw Jacquelene
Published: March 2008

Previous research has demonstrated that parenting programmes can be an effective intervention in changing behaviour and parent/child interactions. However, less attention has been given to the impact of these programmes in relation to improving attendance and behaviour at school. Lynne Rogers, lecturer in teacher education specialising in the post‐14 sector, Susan Hallam, Professor of Education and Dean of the Faculty of Policy and Society, and Jacquelene Shaw, educational psychologist, all working in the University of London, set their debate in this article in the context of the Anti‐Social Behaviour Act 2003 and theRespect Action Plan2006. These authors use their article in order to describe parents’ perceptions of the impact of parenting programmes on their own and their children's behaviour, with particular reference to behaviour at home and at school. The perceptions reported here, and enlivened with direct quotes from parents, are based on questionnaire data from 142 parents and interviews with a sample of parents and teachers. Parents were broadly positive about the benefits of parenting programmes. However, where the child's problem was rooted in school‐related issues, some concerns about behaviour and attendance remained. Lynne Rogers, Susan Hallam and Jacquelene Shaw close their article with a call for parenting programmes to be more closely aligned with activities in school and with educational processes.
Prosodic Modification and Vocal Adjustments in Mothers' Speech During Face‐to‐face Interaction with Their Two‐ to Four‐month‐old Infants: A Double Video Study
Authors: Braarud Hanne Cecilie , Stormark Kjell Morten
Published: March 2008

The purpose of this study was to examine 32 mothers' sensitivity to social contingency during face‐to‐face interaction with their two‐ to four‐month‐old infants in a closed circuit TV set‐up. Prosodic qualities and vocal sounds in mother's infant‐directed (ID) speech during sequences of live interaction were compared to sequences where expressive behaviours were decoupled by presenting either the mothers (Replay 2) or the infants (Replay 1) with a replay record of the partners' former behaviour in a Live 1–Replay 1–Live 2–Replay 2–Live 3 design. Overall, the mothers produced significantly higher amount of ID speech during the live sequences. Compared to the Live 1 sequence, there was a significant reduction in mothers' ID speech during both replay sequences. However, the mothers only recovered ID speech after the Replay 2 sequence, not after the Replay 1. These findings suggest that the emotions signalled by the mothers' ID speech is affected by the contingency of the infant responses.
Identifying Critical Locations in a Spatial Network with Graph Theory
Authors: Demšar Urška , Špatenková Olga , Virrantaus Kirsi
Published: March 2008

Effective management of infrastructural networks in the case of a crisis requires a prior analysis of the vulnerability of spatial networks and identification of critical locations where an interdiction would cause damage and disruption. This article presents a mathematical method for modelling the vulnerability risk of network elements which can be used for identification of critical locations in a spatial network. The method combines dual graph modelling with connectivity analysis and topological measures and has been tested on the street network of the Helsinki Metropolitan Area in Finland. Based on the results of this test the vulnerability risk of the network elements was experimentally defined. Further developments are currently under consideration for eventually developing a risk model not only for one but for a group of co‐located spatial networks.
Efficient Approximation of P‐value of the Maximum of Correlated Tests, with Applications to Genome‐Wide Association Studies
Authors: Li Qizhai , Zheng Gang , Li Zhaohai , Yu Kai
Published: March 2008

Genome‐wide association study (GWAS), typically involving 100,000 to 500,000 single‐nucleotide polymorphisms (SNPs), is a powerful approach to identify disease susceptibility loci. In a GWAS, single‐marker analysis, which tests one SNP at a time, is usually used as the first stage to screen SNPs across the genome in order to identify a small fraction of promising SNPs with relatively low p‐values for further and more focused studies. For single‐marker analysis, the trend test derived for an additive genetic model is often used. This may not be robust when the additive assumption is not appropriate for the true underlying disease model. A robust test, MAX, based on the maximum of three trend test statistics derived for recessive, additive, and dominant models, has been proposed recently for GWAS. But its p‐value has to be evaluated through a resampling‐based procedure, which is computationally challenging for the analysis of GWAS. Obtaining the p‐value for MAX with adjustment for the covariates can be even more time‐consuming. In this article, we provide a simple approximation for the p‐value of the MAX test with or without adjusting for the covariates. The new method avoids resampling steps and thus makes the MAX test readily applicable to GWAS. We use simulation studies as well as real datasets on 17 confirmed disease‐associated SNPs to assess the accuracy of the proposed method. We also apply the method to the GWAS of coronary artery disease.
FROM PMTCT TO A MORE COMPREHENSIVE AIDS RESPONSE FOR WOMEN: A MUCH‐NEEDED SHIFT
Authors: EYAKUZE CYNTHIA , JONES DEBRA A. , STARRS ANN M. , SORKIN NAOMI
Published: March 2008

Half of the 33.2 million people living with HIV today are women. Yet, responses to the epidemic are not adequately meeting the needs of women. This article critically evaluates how prevention of mother‐to‐child transmission (PMTCT) programs, the principal framework under which women's health is currently addressed in the global response to AIDS, have tended to focus on the prevention of HIV transmission from HIV‐positive women to their infants. This paper concludes that more than ten years after their inception, PMTCT programs still do not successfully ensure the adequate treatment, care and support of HIV‐infected women. Of particular concern is the continued widespread use of single‐dose nevirapine despite World Health Organization recommendations to employ more effective combination therapies that do not potentially jeopardize women's future treatment outcomes. In response, the article calls for a more comprehensive approach that places women's health needs at the centre of AIDS responses. This is critical in settings where the pandemic is generalized and there is a push to greatly expand PMTCT programs, as a more effective and equitable way of meeting the needs of women in the context of HIV. Without such a comprehensive approach, women will continue to be impacted disproportionately by the pandemic, and current strategies for prevention, including PMTCT, and treatment will not be as effective and responsive as they need to be.
Singing strategies among male Black‐browed Reed Warblers Acrocephalus bistrigiceps during the post‐fertile period of their mates
Authors: HAMAO SHOJI
Published: March 2008

Bird song is critical to mate attraction. Because singing involves fitness costs, males that sing vigorous and complex songs are thought to be of high quality. Males of the Black‐browed Reed Warbler Acrocephalus bistrigiceps sang actively when they were solitary, but stopped singing as soon as they had attracted a female. Males exhibited two distinct patterns of singing behaviour after the fertile period of their mates: some resumed singing, whereas others did not. Males that resumed singing acquired secondary females more frequently than those that did not sing, suggesting that resuming males seek polygynous mating. The occurrence of extra‐pair fertilization was rare (6.4%) in the study population, and extra‐pair young were sired by both resuming and non‐resuming males. There is no strong evidence that non‐resuming males compensate for their disadvantage in social mate acquisition by extra‐pair paternity. Resuming males arrived at the breeding ground earlier, suggesting that they were high‐quality males.
Excision of Intralaryngeal Granulation Tissue in 25 Horses Using a Neodymium:YAG Laser (1986 to 1991)
Authors: HAY WILLIAM P. , TULLENERS ERIC
Published: March 2008

Granulation tissue masses arising from the axial surface of the arytenoid cartilage in 25 horses were excised using a contact neodymium:yttrium aluminum garnet laser. A technique that eliminated the need for general anesthesia or laryngotomy was developed for transen‐doscopic removal of the masses in standing horses. Nineteen racehorses made abnormal upper respiratory tract noises or their performance was decreased, whereas six horses not used for racing had a history of stertor (five horses) or epistaxis after nasogastric intubation (one horse). Thoroughbreds were significantly (p = .0126) overrepresented compared with the hospital population. The granulation tissue masses were successfully excised and the defect healed in all 25 horses, although a second excision of granulation tissue regrowth was necessary in four horses. In 21 horses, the underlying chondrosis did not progress appreciably. In four horses with preexisting moderate arytenoid cartilage thickening and concurrent laryn‐geal abnormalities, the surgery site healed but the underlying chondrosis progressed substantially. Twelve of 19 (63%) racehorses returned to race at least three times after the surgery. Of the 19 racehorses, five had only slight arytenoid cartilage involvement whereas 14 had moderate cartilage thickening or concurrent laryngeal pathology. All five horses with slight apparent arytenoid cartilage involvement and no concurrent laryngeal pathology returned to racing. Seven of the 14 horses (50%) with moderate underlying cartilage thickening or concurrent laryngeal pathology returned to racing. The six horses not used for racing returned to their previous activity without further respiratory problems.
Effects of Carbon Dioxide Insufflation Combined With Changes in Body Position on Blood Gas and Acid‐Base Status in Anesthetized Llamas(Llama glama)
Authors: LIN HUI‐CHU , BAIRD AUBREY N. , PUGH DAVID G. , ANDERSON DAVID E. , GAUGHAN EARL M.
Published: March 2008

Objective—To study the combined effects of intra‐abdominal CO2insufflation with changes in body position during laparoscopy in xylazine‐ketamine‐halothane anesthetized llamas.

Study Design—Prospective, controlled study.

Animals—Nine castrated, male llamas weighing 114 ± 23 kg, 3 to 13 years old.

Methods—Three llamas (preliminary study [PS] group) were used to study the effect of right lateral, dorsal, and left lateral recumbency on gas exchange and acid‐base status. The other six (experimental study [ES] group) were used to study the combined effects of changes in body position and CO2insufflation to an intraabdominal pressure of 10 to 12 mm Hg. Heart rate, respiratory rate, and indirect arterial blood pressures (systolic [SAP], mean [MAP], and diastolic [DAP]) were recorded every 5 minutes during anesthesia. Arterial blood gases (PaO2and PaCO2) and acid‐base status (pHa and HCO3) were measured immediately after induction of anesthesia and before each change of position.

Results—In the PS group, significant decreases in SAP, MAP and PaCO2and increases in PaO2and pHa were observed when the llamas were turned from right lateral to dorsal recumbency. Values for HCO‐3were lower than the postinduction values, but they remained unaffected by the changes in position. In the ES group, values for MAP were significantly lower when the llamas were placed in dorsal and left lateral recumbency than those observed during right lateral recumbency. Arterial O2tension during right lateral recumbency was lower but returned to preinsufflation values when the llamas were placed in the dorsal position. All llamas recovered uneventfully within 30 minutes after termination of anesthesia.

Conclusions—Insufflation of CO2and changing body position induce minor and transient changes in cardiovascular and respiratory function.

Clinical Relevance—Laparoscopy with mild intra‐abdominal CO2insufflation (10 to 12 mm Hg) can be used safely in spontaneously breathing llamas anesthetized with xylazine, ketamine, and halothane.
Consumption of functional fermented milk containing borage oil, green tea and vitamin E enhances skin barrier function
Authors: Puch Florence , Samson‐Villeger Sandrine , Guyonnet Denis , Blachon Jean‐Luc , Rawlings Anthony Vincent , Lassel Taous
Published: March 2008

Abstract:  As emerging studies show that skin functioning can be improved with orally imbibed ingredients, we decided to investigate a mixture of borage oil, catechins, vitamin E and probiotics, all known for their reported effects on epidermal function, in a fermented dairy product, for the first time. Gamma‐linolenic acid (GLA) and catechins bioavailability and their effects on skin functionality have not been previously investigated from a fermented dairy product. Firstly, we assessed the bioavailability of GLA and catechins mixed in a fermented dairy matrix by measuring their levels in chylomicrons and plasma samples respectively. For the GLA contained in the dairy matrix, the area under the curve and time for maximal absorption were significantly different to the same kinetic parameters compared with absorption from the free oil indicating improved oral bioavailability. However, the overall absorption of catechins over the 6‐h period was identical for both product forms. These results were sufficiently promising to warrant a 24 week skin nutrition intervention study in female volunteers having dry and sensitive skin. The product improved stratum corneum barrier function compared with a control product as early as 6 weeks after the consumption which continued throughout the rest of the study. The reduction in transepidermal water loss relative to control was maintained throughout the trial despite seasonal changes. Moreover, as a result of the enhanced bioavailability, a much greater effect on skin barrier function occurred than reported previously for the individual ingredients. Nevertheless, body mass index significantly influenced various outcome measurements of this study.
Identification of heat shock protein 70 genes HSPA2, HSPA5 and HSPA8 from the Japanese quail, Coturnix japonica
Authors: IWAMOTO Shigehisa , SATO Shinya , HOSOMICHI Kazuyoshi , TAWEETUNGTRAGOON Autthaporn , SHIINA Takashi , MATSUBAYASHI Hisashi , HARA Hiromi , YOSHIDA Yutaka , HANZAWA Kei
Published: March 2008

We have identified three members of the heat shock protein (HSP) 70 family from the Japanese quail, Coturnix japonica. The coding regions of the genes, CjHSPA2, CjHSPA5 and CjHSPA8, exhibit more than 96% similarity to related genes in the chicken, GgHSP70, GgHSPA5 and GgHSC70. The putative proteins encoded by the quail genes contain motifs considered essential for HSP70 family members. In addition, the predicted proteins are more similar to HSPA2, HSPA5, and HSPA8 proteins from vertebrates than they are to other members of the HSP70 family. As is true for orthologs from chicken and mammals, the quail genomic loci consist of a single exon (CjHSPA2) or eight exons (CjHSPA5 and CjHSPA8). The promoter regions of the genes also contain conserved motifs and are similar in structure to promoter regions of related genes in other species. Furthermore, gene order in the regions surrounding the quail HSP70 has been preserved, providing evidence that the genomic regions are orthologous to HSP70‐containing regions in the chicken genome. One of the quail HSP70‐related genes, CjHSPA2, exhibited a robust response to heat shock treatment and transcription of CjHSPA8 mRNA was weakly induced by heat treatment. Taken together, the data suggest that CjHSPA2, CjHSPA5 and CjHSPA8 encode orthologs of HSPA2, HSPA5 and HSPA8 with the notable difference that CjHSPA2 and CjHSPA8 are heat shock‐inducible genes, whereas HSPA2 and HSPA8 are constitutively expressed in a heat shock‐independent manner.
Spatially Periodic Disturbance Rejection With Spatially Sampled Robust Repetitive Control
Authors: Chen Cheng-Lun , Chiu George T.-C.
Published: March 2008

Repetitive controllers have been shown to be effective for tracking periodic reference commands or for rejecting periodic disturbances. Typical repetitive controllers are synthesized in temporal domain where the periods of the reference or disturbance signals are assumed to be known and stationary. For periodic references and disturbances with varying periods, researchers usually resort to adaptive and robust control approaches. For rotational motion systems where the disturbances or reference signals are spatially periodic (i.e., periodic with respect to angular displacement), the temporal period of the disturbance and reference signals will be inversely proportional to the rotational speed and vary accordingly. Motivating by reducing halftone banding for laser printers, we propose a design framework for synthesizing spatially sampled repetitive controller by reformulating a linear time-invariant system subject to spatially periodic disturbances using angular displacement as the independent variable. The resulting nonlinear system can be represented as a quasi-linear parameter-varying (quasi-LPV) system with the angular velocity as one of the varying state-dependent parameters. An LPV self-gain–scheduling controller that includes a spatially sampled repetitive control can be designed to take into consideration bounded model uncertainty and input nonlinearity, such as actuator saturation. Using the signal from an optical encoder pulse as a triggering interrupt, experimental results verified the effectiveness of the proposed approach in rejecting spatially periodic disturbances that cannot be compensated with fixed period temporal repetitive controllers.
Adaptive Observer for Fault Diagnosis in Nonlinear Discrete-Time Systems
Authors: Caccavale F. , Pierri F. , Villani L.
Published: March 2008

This paper deals with the problem of fault diagnosis (FD) for a class of nonlinear systems. The scheme is based on a discrete-time diagnostic observer that computes a prediction of the system’s state. Compensation of the fault effect on the state prediction is achieved via an adaptive discrete-time approach, based on a parametric model of the faults. A stability proof is developed to prove the global exponential stability of the state estimates. A solution for fault isolation and identification is also proposed, based on a postfault analysis. The proposed FD approach is applied and experimentally tested on a conventional industrial robot manipulator.
Optimal Control of Tandem Cold Rolling Using A Pointwise Linear Quadratic Technique With Trims
Authors: Pittner John , Simaan Marwan A.
Published: March 2008

The tandem cold rolling of metal strip is a complex multivariable process whose control presents a significant engineering challenge because of the complex interaction between the process variables, the nonlinearities (which change with operating conditions), and the interstand time delays (which change significantly with the mill speed). The present technology generally relies on a control structure that has been successful in producing an acceptable output, but has limited capability for improvement in performance. This paper describes a new strategy for control of the mill that overcomes many limitations of the present controllers. The new strategy is based on a pointwise linear quadratic technique wherein a state-dependent algebraic Riccati equation is solved pointwise to establish a control law for a multiinput–multioutput controller, with appropriate trimming functions. For this application, the features of this novel strategy compare favorably to those of other techniques for control of nonlinear systems in the areas of simplicity of implementation, provision for the use of physical intuition in the design process, and strong robustness to disturbances and uncertainties. During simulations using the new controller coupled to a nonlinear model of the process, the tolerance in mill exit thickness was ∼0.2% for several rolling schedules using mild steel during operations at steady speed and during speed changes, and in the presence of typical disturbances with uncertainties in modeling and measurement. This offers the potential for improvement over present industrial controllers, which typically hold the tolerance in mill exit thickness to within 0.5–0.8%. In addition, excursions in the individual mill stand output thicknesses and interstand tensions are reduced, which contributes to the stability of the rolling process.
A New Tracking Controller Design for Underwater Vehicles Using Quadratic Stabilization
Authors: Kumar R. Prasanth , Dasgupta Anirvan , Kumar C. S.
Published: March 2008

This paper proposes a new tracking controller for autonomous underwater vehicles (AUVs) using the concept of simultaneous quadratic stabilization. The nonlinear underwater vehicle system is viewed as a set of locally linear time invariant systems obtained by linearizing the system equations on the reference trajectory about some discrete points. A single stabilizing controller is then designed for the set of systems so obtained. However, this controller requires the exact parameters of the system. Since the hydrodynamic parameters of AUVs are generally not known with sufficient accuracy, the proposed controller is used for the known part of the dynamics and an adaptation algorithm is used to estimate the unknown parameters online and compensate for the rest of the plant dynamics. The proposed controller can thus adaptively handle the complete nonlinear uncertain dynamics of the plant. Simulation results are presented and discussed for a typical AUV.
Understanding the Knowledge Needs of Designers During Design Process in Industry
Authors: Vijaykumar Gokula , Chakrabarti Amaresh
Published: March 2008

Product success is substantially influenced by satisfaction of knowledge needs of designers, and many tools and methods have been proposed to support these needs. However, adoption of these methods in industry is minimal. This may be due to an inadequate understanding of the knowledge needs of designers in industry. This research attempts to develop a better understanding of these needs by undertaking descriptive studies in an industry. We propose a taxonomy of knowledge, and evaluate this by analyzing the questions asked by the designers involved in the study during their interactions. Using the taxonomy, we converted the questions asked into a generic form. The generic questions provide an understanding about what knowledge must be captured during design, and what its structure should be.
Autonomy and negatively informed consent
Authors: Kihlbom U
Published: March 2008

The requirement of informed consent (IC) to medical treatments is almost invariably justified with appeal to patient autonomy. Indeed, it is common to assume that there is a conceptual link between the principle of respect for autonomy and the requirement of IC, as in the influential work of Beauchamp and Childress.

In this paper I will argue that the possible relation between the norm of respecting (or promoting) patient autonomy and IC is much weaker than conventionally conceived. One consequence of this is that it is possible toexerciseyour autonomy without having the amount of and the kind of information that are assumed in the standard requirement of IC to medical treatments. In particular, I will argue that with a plausible conception of patient autonomy, the respect for and the promotion of patient autonomy are in certain circumstances better protected by giving patients the right to give theirnegatively informedconsent to medical treatments.
Research ethics and lessons from Hwanggate: what can we learn from the Korean cloning fraud?
Authors: Saunders R , Savulescu J
Published: March 2008

In this review of the Korean cloning scandal involving Woo-Suk Hwang, the nature of the disaster is documented and reasons why it occurred are suggested. The general problems it raises for scientific research are highlighted and six possible ways of improving practice are offered in the light of this case: (1) better education of science students; (2) independent monitoring and validation; (3) guidelines for tissue donation for research; (4) fostering of debate about ethically contentious research in science journals; (5) development of an international code of ethical research practice; (6) fostering of public involvement in ethical review and debate through the web.
A synoptic key to the genus Eupenicillium and to sclerotigenic Penicillium species
Authors: Pitt John I.
Published: March 2008

A synoptic key to Eupenicillium and sclerotigenic Penicillium species is presented. Based on cultural characters and the imperfect state, it enables identifications to be made after 7 days incubation, avoiding the necessity of awaiting maturation of the perfect state.
Inheritance of buff spore color and of virulence on the cultivar Warrior in loose smut of barley, Ustilago nuda
Authors: Fullerton R. A. , Nielsen J.
Published: March 2008

A technique to perform intraspecific crosses in Ustilago nuda (Jens.) Rostr. was developed and applied to study the inheritance of buff spore color and the inheritance of virulence on the cultivar Warrior. The buff spore color of an albino strain was recessive to the brown color of the wild type. Virulence on Warrior was also recessive. This virulence and that on the cultivar Titan has been transferred from a wild-type strain into the buff strain.
Karyology of conidiogenesis and endoconidium germination in Thielaviopsis basicola
Authors: Huang H. C. , Patrick Z. A.
Published: March 2008

Cytological studies on Thielaviopsis basicola revealed that other than a low frequency of multinucleate endoconidia in some isolates the uninucleate condition prevailed. Of the six isolates that were studied, three possessed some multinucleate spores. The nuclei in a multinucleate endoconidium were all derived by successive mitotic divisions of the single generative nucleus in the conidiophore. The nuclei in the multinucleate endoconidium divided independently and segregated into uninucleate and (or) multinucleate components during the course of endoconidial germination and subsequent hyphal development. The implications of the results are discussed with regard to the occurrence of cultural variability in this fungus.
Colleter anatomy in red mangrove, Rhizophora mangle (Rhizophoraceae)
Authors: Lersten Nels R. , Curtis John D.
Published: March 2008

A mass of colleters occurs at the base of each of the large paired stipules, which form a sealed cone around the bud. Each colleter is a finger-like protuberance about 1 mm in height, with a relatively massive axis of elongate cells surrounded by epidermal cells elongated perpendicular to the axis. No special association of vascular bundles with colleters was observed, nor were any transfer cells seen. Rhizophora colleters are remarkably similar to those found in several other families.
Characteristics of two fungi producing ectendomycorrhizae in Pinus resinosa
Authors: Wilcox Hugh E. , Ganmore-Neumann Ruth , Wang C. J. K.
Published: March 2008

Two unidentified, imperfect fungi were isolated from 3-year-old nursery seedlings of red pine. One, referred to as BDG-58, appears to be very similar to the E-strain fungus isolated by Mikola in Finland. It is light brown in culture with septate, smooth to verrucose hyphae, 4.4–8.8 microns (μ) in diameter. It produces large spherical chlamydospores, 45–100 μ in diameter, in a peat moss – vermiculite – nutrient medium substrate used in mycorrhizal synthesis experiments with red pine. Chlamydospores are terminal on chains of 3–15 supporting cells. Associated with the roots, chlamydospores are more variable in form, being terminal and solitary, occasionally sessile, or intercalary. The intercalary may be either solitary or in chains. This fungus forms ectendomycorrhizae which possess a coarse Hartig net and coarse, heavily branched intracellular hyphae.The second fungus, referred to as BDD-22, is black in culture with smooth or minutely echinulate hyphae mostly 3 μ in diameter and torulous (or moniliform) hyphae 6.6 μ in diameter. Conidiophores and conidia are abundant in modified Hagem's liquid medium at 6 months. Conidiophores are semimacronematous, solitary or branched, 20–70 μ long, greenish-black and smooth. Conidiogenous cells are phialidic and collarettes are readily discernible. Chlamydospore-like cells are common, solitary or in chains. The fungus, tentatively identified as a Chloridium, forms ectendomycorrhizae which possess fine intercellular hyphae and masses of spherical intracellular bodies which are spore-like in appearance.
Ecological strategy and tactics of Equisetum sylvaticum during a postfire succession
Authors: Beasleigh W. J. , Yarranton G. A.
Published: March 2008

The proportion of the total aerial dry weight of Equisetum sylvaticum devoted to spore producing and supporting structures does not change in the first 6 years of postfire succession: the ecological strategy remains constant. However, the stem and branch lengths of sterile shoots, their time of appearance, and the distribution of dry weight between sterile shoots do vary during the same period, indicating changes in ecological tactics. The tactical changes appear to be a response to increasing competition. Clones of E. sylvaticum survive repeated fires by means of the deeply buried rhizomes and are evidently very long-lived.
Heterotrophic potential of Phormidium and other blue-green algae
Authors: Pope Daniel H.
Published: March 2008

Several algal types were tested for the ability to assimilate a variety of organic compounds including glucose, sucrose, glycerol, acetate, and a variety of amino acids. Axenic cultures of Phaeodactylum tricornutum, Cricosphaera sp., and Dunaliella tertiolecta failed to take up any of the compounds tested. Axenic cultures of the filamentous blue-green algae Phormidium sp. and Lyngbya sp. took up all of the test substrates, as did the "olive-green cells" (a non-bacteria-free sample of marine algal cells described as olive-green cells by other workers). The results of experiments to determine uptake rates over the range 10−7 to 10−3 molar substrate, rates of uptake at 18, 24, and 32C, and rates of uptake in the presence of the metabolic inhibitors dinitrophenol (DNP) and carbanyl cyanide m-chlorophenylhydrazone (CCCP) indicated that uptake of the organic compounds tested by the filamentous blue-green algae tested is not by an active transport mechanism.
Cytological study of the introduction of Agrobacterium tumefaciens spheroplasts into Vinca rosea protoplasts
Authors: Hasezawa Seiichiro , Matsui Chiaki , Nagata Toshiyuki , Syono Kunihiko
Published: March 2008

The process of the introduction of Agrobacterium tumefaciens spheroplasts into Vinca rosea protoplasts was examined by transmission electron microscopy. Shortly after the addition of polyethylene glycol (PEG) or polyvinyl alcohol (PVA) the spheroplasts adhered tightly to the surface of the protoplasts and after 10 min they were engulfed by endocytosis. The engulfed spheroplasts then lost their integrity and their components seemed to disperse into the cytoplasm of the protoplasts. Although the treatment with PEG or PVA was indispensable in this process, these polymers had slightly different effects. The cytoplasm of the protoplasts treated with PEG looked darker and thinner than that treated with PVA. The uptake of spheroplasts by protoplasts was also examined quantitatively by 4,6-diamidino-2-phenylindole (DAPI) staining and fluorescence microscopy. About 70–80% of protoplasts incorporated the spheroplasts after PEG or PVA treatment. Usually about 10 DAPI-stained spheroplasts were observed in a protoplast. These observations are discussed in relation to our previous report on the transformation of V. rosea protoplasts by A. tumefaciens spheroplasts.
Polarity of regeneration in excised leaves of Crassula argentea. I. A role of auxin
Authors: Paterson Karol E.
Published: March 2008

High concentrations of four auxins, naphthalene acetic acid, indole 3-acetic acid, 2,4-dichlorophenoxyacetic acid, and indole 3-butyric acid, added to leaf segments of Crassula argentea in agar culture eliminate the strong polarity of the regeneration by inducing the formation of distal plantlets. The auxins also changed the normal wound response by inducing the formation of callus on the cut surfaces. All of the auxins increased the numbers of roots formed and inhibited the number of shoots. Unlike cytokinin, which had no effect on the polarity but altered the developmental sequence of regeneration, none of the auxins had any effect on the normal developmental sequence of regeneration, but did affect the morphology of the newly formed roots. There were differential concentration responses for each of the four auxins.
Pollination of northeastern North American Spiranthes (Orchidaceae)
Authors: Catling Paul M.
Published: March 2008

Most northeastern North American Spiranthes are adapted to pollination by long-tongued bees (e.g., Bombus spp. and Megachilidae). The salient features of this adaptation are (i) a long, flat viscidium which attaches the pollinia readily to the flat rigid galea of the insect's proboscis, (ii) the nectar secreted into the base of the floral tube, (iii) the flowers are protandrous and sequential beginning at the base. In contrast, Spiranthes lucida apparently is pollinated largely by halictine bees. It differs from other northeastern taxa of Spiranthes in (i) having an oval viscidium which attaches the pollinia to the clypeus below the antennae, (ii) having the nectar available on the under side of the column behind the stigmatic surface, and (iii) in lacking protandry. In the characteristically Bombus-pollinated taxa, protandry is accomplished by a change in the position of the terminal portion of the column with respect to the lip, apparently due to cell elongation in both the column and the lip. The present investigation documents protandry in S. cernua var. cernua, S. lacera var. lacera, S. lacera var. gracilis, S. laciniata, S. magnicamporum, S. ochroleuca, S. romanzoffiana, S. tuberosa, and S. vernalis. Bees moving up the spike from the older female flowers to the younger male flowers act initially as pollen donors and later as pollen receivers; thus cross-fertilization is enhanced. Halictines occasionally act as pollinators of characteristically Bombus-pollinated taxa by visiting the flowers upside down so that the pollinia are inconspicuously attached to the lower side of the prementum. Data presently available for northeastern North American Spiranthes fail to establish pollinator specificity as significant in speciation except perhaps with respect to the separation of S. lucida from the other 14 northeastern taxa.
Levels of maturation of protoxylem and protophloem elements in aerial roots of Cissus and Ficus
Authors: Sivaramakrishna D. , Vijayaraghavan Prabha
Published: March 2008

The levels of maturation of protophloem and protoxylem elements in the adventitious aerial roots of Cissus quadrangularis and Ficus benghalensis are reported on the basis of serial sections of a large number of root apices. The aerial roots of Cissus resemble the roots of other taxa that have been studied in having the mature protophloem elements at a level distal to that where maturation of protoxylem elements occurs; those of Ficus show an inverse order, protophloem elements occurring proximal to protoxylem elements. In both the species studied, wide variations in levels of maturation of protophloem elements are noted in some roots, while others show a wide variation in levels of protoxylem elements. It is suggested that rates of growth and rates of the maturation process operating independently are involved.
Nectria haematococca mating population. VI. Cultural parameters affecting growth, conidiation, and perithecial formation
Authors: Dietert Margaret F. , VanEtten Hans D. , Matthews Patty S.
Published: March 2008

Field and ascospore isolates of Nectria haematococca mating population VI were examined to determine the influence of culture conditions on growth of the sexual and asexual forms of the organism. A broad pH tolerance was noted for both mycelial growth and sexual fertility. Photoperiod did not affect mycelial growth, but strongly influenced the number and type of conidia and macroconidial size. The size, type, and number of conidia produced were also isolate and temperature dependent. The temperature optimum for mycelial radial growth was 27–30 °C for all of the isolates. Temperatures of 18–24 °C before and 21–24 °C after spermatization were most favorable for perithecium production and ascospore formation. A light requirement for perithecium and ascospore production could be satisfied by exposing the fungus to light either before or after spermatization. Light intensities from 120 to 3800 lx were sufficient to induce perithecium and ascospore formation, but at temperatures above or below the optimum for perithecia formation, a higher light intensity enhanced the fertility of the cross. Of the various media tested, a complex medium (V-8 agar medium) and a simple medium (Czapek–Dox) served best for production of the sexual stage.
Radioautographic visualization of β-glucans formed by pea membranes from UDP-glucose
Authors: Mueller Susette C. , Maclachlan Gordon A.
Published: March 2008

Radioautographic experiments were carried out using pea stem slices to determine the site of glucose incorporation from UDP-glucose. Cut or damaged pea stem cells were the only cells to incorporate [3H]glucose from UDP-[3H]glucose. The product formed at 20 μM UDP-glucose was observed in electron microscope thin sections in patches on the plasma membrane and the cell wall. The product formed at 5 mM UDP-glucose occurred in fibrillar bundles that stretched between the plasma membrane and the cell wall. This periplasmic material fluoresced when stained with aniline blue. Experiments in which slices were subjected to sequential incubations in radioactive 5 mM UDP-glucose followed by unlabelled 5 mM UDP-glucose, or incubations in the reverse order, indicated that incorporation of [3H]glucose into products insoluble in chloroform:methanol:water or hot water occurs at the plasma membrane, and radioactivity is displaced from the membrane by subsequent incubations. A similar experiment, in which slices were first incubated in radioactive 20 μM UDP-glucose followed by unlabelled 5 mM UDP-glucose, indicated that the synthesis of fibrillar material from 5 mM UDP-glucose displaces the labelled product that had been formed from 20 μM UDP-glucose. It is concluded that only cut or damaged pea stem cells utilize UDP-glucose and the plasma membrane enzymes that incorporate [3H]glucose from 20 μM or 5 mM UDP-[3H]glucose are in close physical proximity.
Arachnoxylon from the Middle Devonian of southwestern Virginia
Authors: Stein Jr. William E. , Wight David C. , Beck Charles B.
Published: March 2008

Eight specimens from the Middle Devonian Purcell Member of the Millboro Shale Formation in southwestern Virginia conform to a recent definition of the previously monotypic genus Arachnoxylon. The new material provides supplementary information on several tissue regions of the main axis, including evidence on variability in the structure of the protoxylem, and on departure of the large, or "major" traces. In addition, evidence is provided here for the first time on a discrete region, immediately adjacent to the primary xylem, containing probable conducting elements of the primary phloem, on the structure of the epidermis, and on the presence of multicellular superficial emergences. Although clearly assignable to Arachnoxylon, all but one of our specimens vary significantly from previous specimens in the genus in several features which may be interpreted as relating directly or indirectly to size. It is possible that all specimens in Arachnoxylon represent portions of a single kind of plant. However, organic connection between the large and small forms has not been demonstrated. We elect, therefore, to establish A. minor sp. n. for the smaller specimens.
Changes in water relations and cell permeability in relation to ageing of excised squash hypocotyls: a reappraisal
Authors: Hancock J. G.
Published: March 2008

Osmotic potentials (ψs) of squash hypocotyl sections increased when sections were aged in water. On the other hand, the ψs of sections aged in moist air or 0.15 M mannitol did not differ significantly from freshly excised tissues. The influence of the manner of ageing of hypocotyl tissues on urea uptake found in a previous study was possibly related to the effects of these treatments on ψs. For example, urea uptake was affected most strongly by the same ageing procedures that caused the greatest changes in ψs, especially incubation of hypocotyl sections in water. Because of greater losses of cellular solutes, the turgor pressures developed by tissues aged in water would have been lower than in other tissues when urea uptake was measured under standard hypotonic conditions. The present investigation supports the interpretation by a number of workers that turgor pressure may directly or indirectly modify permeability characteristics of plant cell membranes.
Geochemistry of Sainte-Marguerite volcanic rocks: implications for the evolution of Silurian–Devonian volcanism in the Gaspé Peninsula
Authors: D’hulst Alan , Beaudoin Georges , Malo Michel , Constantin Marc , Pilote Pierre
Published: March 2008

The Lower Devonian Sainte-Marguerite volcanic rocks are part of a Silurian–Devonian volcanic sequence deposited between the Taconian and Acadian orogenies in the Gaspé Peninsula, Quebec, Canada. The Sainte-Marguerite unit includes basaltic and dacitic lava flows with calc-alkaline and volcanic-arc affinities. Such affinities are also recorded by the trace-element signature in Lower Silurian and most Lower Devonian volcanic units of the Gaspé Peninsula. However, most of the other Silurian–Devonian volcanic rocks occurring in the Gaspé Peninsula have been previously interpreted to have erupted in an intracontinental setting. A back-arc setting for the Gaspé Peninsula between the Taconian and Acadian orogenies could account for these subduction volcanic-arc signatures, though a metasomatized lithospheric mantle magma source, unrelated to subduction, cannot be excluded. Lower Silurian and Lower Devonian volcanic rocks in the central part of the Gaspé Peninsula show an arc affinity, whereas Upper Silurian and Lower to Middle Devonian volcanic rocks, located in the south and north of the Gaspé Peninsula, respectively, show a within-plate affinity. The Lower Devonian Archibald Settlement and Boutet volcanic rocks of the southern and northern Gaspé Peninsula, respectively, show a trend toward a within-plate affinity. This suggests that within-plate volcanism migrated from south to north through time in an evolving back-arc environment and that the subduction signature of Lower Silurian and Lower Devonian rocks results from a source that melted only under the central part of the Gaspé Peninsula.
The Eocene–Oligocene magmatic hiatus in the south-central Canadian Cordillera: a capture of the Kula Plate by the Pacific Plate?
Authors: Dostal Jaroslav , Keppie J Duncan , Church B Neil , Reynolds Peter H , Reid Cheryl R
Published: March 2008

The Tertiary (Paleogene and Neogene) geological record in south-central Canadian Cordillera is dominated by the 350–400 km wide, lower Eocene volcanic arc and the overlying Miocene–Recent back-arc lavas that are separated by a hiatus in magmatic activity between 48 and 24 Ma. In the Black Dome area (~240 km north of Vancouver), the Eocene volcanic rocks are mainly continental margin calc-alkaline andesite and dacite, resulting from the melting of a juvenile mafic source at the base of the crust. In contrast, the Miocene volcanic rocks resemble continental flood basalts. Both Eocene and Miocene rocks from the Black Dome volcanic complex have high positive εNd values (+7.2 to +7.4 and +6.4 to +7.6, respectively) and low initial Sr isotopic ratios (0.702 516 – 0.703 528 and 0.703 376 – 0.703 392, respectively) comparable to modern oceanic basalts. The onset of the hiatus in magmatism at 48 Ma coincides with capture of the Kula Plate by the Pacific Plate resulting in a change in convergence direction with the North American Plate from orthogonal to margin-parallel. The margin-parallel motion is inferred to have removed a 50–100 km sliver of the Eocene forearc that formed the boundary between the Pacific and subducted Kula Plate. Reinitiation of arc magmatism at 24 Ma is related to subduction of the Farallon and associated plates and it superimposed back-arc tholeiitic magmatism on top of the Eocene arc.
Internal structure and the thermal and hydrological regime of a typical lithalsa: significance for permafrost growth and decay
Authors: Calmels Fabrice , Delisle Georg , Allard Michel
Published: March 2008

This study presents new knowledge about the ice segregation and frost-heave processes taking place in a typical lithalsa. A tomodensitometric scanner was used to produce high-resolution computer images of ice lenses, soil layers, faults, sedimentary structures, and gas bubbles. Scan-image analysis allowed the interpretation of the ice lenses and soil cryostructures resulting from permafrost aggradation. It also provided an accurate estimation of volumetric contents of ice and gas present in the permafrost. Isotopic analyses on the various phases of the permafrost (i.e., ice, gas, and soil) provided supplementary information. 18O, deuterium, and tritium analyses were undertaken on ground ice and on surface water. Monitoring of the thermal regime of the lithalsa provided clues relative to gradients that drive groundwater movements and ice-lens growth. Compilation and interpretation of the data in a three-dimensional and temporal context suggest that the lithalsa under study grew under climate conditions slightly colder than those of the 20th century. However, post-aggradational water penetrated into the permafrost of the lithalsa. Ground temperatures increased since 2000, most likely because of underground warming owing to groundwater flow around the permafrost body. As a result, the mound has started to settle down, and an incipient thermokarst pond became conspicuous in 2003.
The relative importance of local, lateral, and longitudinal variables on the development of habitat quality models for a river
Authors: Bouchard Judith , Boisclair Daniel
Published: March 2008

Fish habitat quality models (FHQM) developed for rivers consist of relationships between indices of habitat quality and environmental conditions prevailing within sites (local variables). Given the hierarchical structure of these ecosystems, modeling habitat quality over complete rivers may require the inclusion of variables in FHQM that represent the processes operating over a more complete range of spatial scales. The objectives of this study were to quantify the relative importance of local, lateral (characteristics of the shores), and longitudinal (attributes along the upstream–downstream axis of the river) variables on a FHQM developed for parr of Atlantic salmon (Salmo salar). Parr densities (an index of habitat quality) and local, lateral, and longitudinal variables were estimated in 32 reaches of 200 m. FHQM were developed using analytical units (AU) of 50, 100, and 200 m (length of AU in the upstream–downstream axis of the river). The structure and the explanatory power of FHQM were affected by the AU size. In the study river, 98% of the explanatory power of FHQM was imputed to the effect of local variables.