bluuebunny/crossref_metadata_2025 huggingface dataset:
Stratification for the propensity score compared with linear regression techniques to assess the effect of treatment or exposure
Authors: Senn Stephen , Graf Erika , Caputo Angelika
Published: December 2007

Stratifying and matching by the propensity score are increasingly popular approaches to deal with confounding in medical studies investigating effects of a treatment or exposure. A more traditional alternative technique is the direct adjustment for confounding in regression models.

This paper discusses fundamental differences between the two approaches, with a focus on linear regression and propensity score stratification, and identifies points to be considered for an adequate comparison. The treatment estimators are examined for unbiasedness and efficiency. This is illustrated in an application to real data and supplemented by an investigation on properties of the estimators for a range of underlying linear models. We demonstrate that in specific circumstances the propensity score estimator is identical to the effect estimated from a full linear model, even if it is built on coarser covariate strata than the linear model. As a consequence the coarsening property of the propensity score—adjustment for a one‐dimensional confounder instead of a high‐dimensional covariate—may be viewed as a way to implement a pre‐specified, richly parametrized linear model. We conclude that the propensity score estimator inherits the potential for overfitting and that care should be taken to restrict covariates to those relevant for outcome. Copyright © 2007 John Wiley & Sons, Ltd.
Assessing surrogacy from the joint modelling of multivariate longitudinal data and survival: Application to clinical trial data on chronic lymphocytic leukaemia
Authors: Deslandes Emmanuelle , Chevret Sylvie
Published: December 2007

In clinical research, we are often interested in assessing how a biomarker changes with time, and whether it could be used as a surrogate marker when evaluating the efficacy of a new drug. However, when the longitudinal marker is correlated with survival, linear mixed models for longitudinal data may be inappropriate. By contrast, it may be possible to recover information from the so‐called informative censoring by modelling both the longitudinal information and the survival process. The objective of this work is to jointly model longitudinal and survival data to assess surrogacy. Two competitive modelling strategies were used, either a multistate model summarizing the course of longitudinal data and occurrence of disease progression or death, or a joint longitudinal‐survival model. We present both analyses based on a case study from two randomized clinical trials that enrolled patients with stage A chronic lymphocytic leukaemia (CLL) in order to obtain further insights into these different approaches. Copyright © 2007 John Wiley & Sons, Ltd.
Robustness of a parametric model for informatively censored bivariate longitudinal data under misspecification of its distributional assumptions: A simulation study
Authors: Pantazis Nikos , Touloumi Giota
Published: December 2007

Repeated measurements of surrogate markers are frequently used to track disease progression, but these series are often prematurely terminated due to disease progression or death. Analysing such data through standard likelihood‐based approaches can yield severely biased estimates if the censoring mechanism is non‐ignorable. Motivated by this problem, we have proposed the bivariate joint multivariate random effects (JMRE) model, which has shown that when correctly specified it performs well in terms of bias reduction and precision.

The bivariate JMRE model is fully parametric and belongs to the class of shared parameters joint models where a survival model for the dropouts and a mixed model for the markers' evolution are linked through a multivariate normal distribution of random effects. As in every parametric model, robustness under violations of its distributional assumptions is of great importance. In this study we generated 500 simulated data sets assuming that random effects jointly follow a heavy‐tailed distribution, two skewed distributions or a mixture of two normal distributions. Moreover, we generated data where level‐1 errors or residuals in the survival part of the model follow a skewed distribution. Further sensitivity analysis on the effects of reduced sample size, increased level‐1 variances and altered fixed effects values was also performed.

We found that fixed effects estimates are almost unaffected, but their standard errors (SEs) may be underestimated especially under heavily skewed distributions. The proposed model seems robust enough, but its performance on smaller data sets or under more extreme departures of its assumptions needs further investigation. Copyright © 2007 John Wiley & Sons, Ltd.
Properties of Cast Films Made of HCl‐Methanol Modified Corn Starch
Authors: Chung Yi‐Lin , Lai Hsi‐Mei
Published: December 2007

The molecular and physicochemical properties of the studied starches modified with 0.36% HCl in methanol at 25 °C and 45 °C were related to the film properties of these starches. The weight‐averaged molecular weight (Mw) and the number of long‐chain branches (DP 13‐36) of HCl‐methanol modified starch decreased with increasing degree of acid modification, but the number of short‐chain branches (DP < 6) increased. HCl‐methanol modification significantly decreased the ghost formation in gelatinized starch dispersions and the viscosity of starch film‐forming dispersions. Thus, the homogeneity of the produced starch films was improved and their opacity reduced. Proper HCl‐methanol modification produced corn starch films with lower moisture absorption rate and maximum moisture content under high relative humidity (RH = 97%) condition.
Effects of Soy Protein on Physical and Rheological Properties of Wheat Starch
Authors: Ribotta Pablo D. , Colombo Andrés , León Alberto E. , Añón M. Cristina
Published: December 2007

It is necessary to understand the interaction phenomena between proteins and polysaccharides for the development of starch‐based products with better physical and sensory properties. A simplified model system was chosen to study the influence of soy protein on physical and rheological properties of wheat starch and the possible interactions between them. Thermal and pasting behaviors of the slurries and texture properties, water retention capacity and ultra structure of soy protein‐wheat starch gels were analyzed. While soy protein isolate increased the viscosity of starch suspension during and after heating, gels with soy protein presented a weaker structure than wheat starch gels. Results suggested association between leached out material and swollen granule surface of starch with soy protein. Scanning electron microscopy reflected these changes in the gel ultrastructure.
A wideband MIMO channel model derived from the geometric elliptical scattering model
Authors: Pätzold Matthias , Hogstad Bjørn Olav
Published: December 2007

In this paper, we present a reference model for a wideband multiple‐input multiple‐output (MIMO) channel based on the geometric elliptical scattering model. The model takes into account the exact relationship between the angle of departure (AOD) and the angle of arrival (AOA). Based on this relationship, the statistical properties of the reference model are studied. Analytical solutions are presented for the three‐dimensional (3D) space‐time cross‐correlation function (CCF), the temporal autocorrelation function (ACF), the 2D space CCF, and finally the frequency correlation function (FCF). The correlation properties are studied and visualized under the assumption of isotropic as well as non‐isotropic scattering conditions. The proposed reference model can be used as a starting point for the derivation of a frequency‐selective space‐time MIMO channel simulator enabling the performance evaluation of multi‐antenna wideband communication systems. The reference model is also quite useful for studying the MIMO channel capacity under various propagation conditions imposed by the geometry of the underlying scattering model. Copyright © 2007 John Wiley & Sons, Ltd.
Mitigating the impact of node mobility on ad hoc clustering
Authors: Ghosh Rituparna , Basagni Stefano
Published: December 2007

This paper explores the impact of node mobility on distributed and mobility adaptive clustering (DMAC), a typical clustering protocol for mobile ad hoc networks. In particular, in this paper we evaluate the cost of maintaining the DMAC clustering structures when the nodes move according to three different mobility models, namely, the random way point model, the Brownian motion and the Manhattan mobility model. Via ns2‐based simulations, we have observed that the mobility models have different impact on protocol performance. The general trend, however, appears to be the same for networks of increasing size. The second contribution of this paper concerns investigating ways of mitigating the impact of mobility on the clustering structure and hence over the overall network performance. We consider a generalization of DMAC (GDMAC) where rules are established to decrease the number of cluster updates. Via simulation we have observed that GDMAC is effective in reducing the clustering overhead imposed by mobility, and the corresponding maintenance cost. Copyright © 2007 John Wiley & Sons, Ltd.
A modified hopfield network for mobility management
Authors: Taheri Javid , Zomaya Albert Y.
Published: December 2007

This paper presents a new approach to solving the mobile location management problem using the Paging Cells (PCs) scheme. In this approach (HNN‐BDT‐PC), a combination of the Hopfield Neural Network (HNN) and the author's Ball Dropping Technique (BDT) is used to solve the problem. To this end, the location management cost of a network is embedded in the HNN parameters, and by iteration, the mobile network gradually moves toward an optimal state. The approach is inspired by the phenomenon that results from the natural movement of balls when they are dropped onto a non‐even plate (a plate with troughs and crests). Each trough of the plate corresponds to a PC, and the network corresponds to the whole plate. The aim is to find optimal PC configuration (i.e., the troughs) of the network. Three main procedures are used in the optimization process; in each optimization cycle, the HNN is launched to move the balls around the plate, and, by analogy, to move the PCs around the network to find the best configuration. Copyright © 2007 John Wiley & Sons, Ltd.
A UTP semantics for
Circus
Authors: Oliveira Marcel , Cavalcanti Ana , Woodcock Jim
Published: December 2007

Circus specifications define both data and behavioural aspects of systems using a combination of Z and CSP constructs. Previously, a denotational semantics has been given to Circus; however, a shallow embedding of Circus in Z, in which the mapping from Circus constructs to their semantic representation as a Z specification, with yet another language being used as a meta-language, was not useful for proving properties like the refinement laws that justify the distinguishing development technique associated with Circus. This work presents a final reference for the Circus denotational semantics based on Hoare and He’s
Unifying Theories of Programming
(UTP); as such, it allows the proof of meta-theorems about Circus including the refinement laws in which we are interested. Its correspondence with the CSP semantics is illustrated with some examples. We also discuss the library of lemmas and theorems used in the proofs of the refinement laws. Finally, we give an account of the mechanisation of the Circus semantics and of the mechanical proofs of the refinement laws.
An Improved Method for Preparing Dimethyl Disulfide Adducts for GC/MS Analysis
Authors: Shibahara Akira , Yamamoto Kouhei , Kinoshita Akemi , Anderson Barbara L.
Published: December 2007

Dimethyl disulfide (DMDS) adducts are prepared from fatty acid methyl esters to locate the double‐bond position in monoenoic fatty acids by gas chromatography/mass spectrometry. We improved our original procedure for preparing DMDS adducts with a simple device that can be made in any laboratory using a glass pipette and silica based packing material, Extelut NT.
Priapism in a castrated cat associated with feline infectious peritonitis
Authors: Rota Ada , Paltrinieri Saverio , Jussich Selina , Ubertalli Giuseppe , Appino Simonetta
Published: December 2007

This report describes a case of feline infectious peritonitis (FIP) in a castrated cat which first presented with the unusual sign of priapism. Laboratory examinations showed increased serum protein content and decreased albumin/globulin ratio. Serum electrophoresis revealed increased α2- and γ-globulin content. One month after the first examination, the cat died. At necropsy, histopathological evaluation of organs showed inflammatory granulomatous lesions compatible with non-effusive FIP and coronavirus-specific polymerase chain reaction confirmed the diagnosis. FIP antigen was demonstrated immunohistochemically in penile tissue.
Environmental associations of sponges in the Spermonde Archipelago, Indonesia
Authors: Cleary Daniel F.R. , de Voogd Nicole J.
Published: December 2007

Relatively little is known about spatial turnover of marine benthic taxa in the diverse reef environments of Indonesia and how this is structured by environmental conditions. In the present study the community similarity of sponges was related to environmental and spatial variables. In total, 150 sponge species (N=15,842) were sampled within the Spermonde Archipelago in the Makassar Strait, off south-west Sulawesi. Ordination revealed that sponges are primarily structured by a complex interaction between depth, exposure and on-to-offshore variation in environmental variables. Together, environmental and spatial variables explained 56.9% of the variation in similarity of which 10.9% was due to environmental variables alone, 2.6% due to spatial variables alone and 43.4% due to covariation of environmental and spatial variables. The large amount of variation explained by the spatially structured environmental component is due to a strong on-to-offshore gradient in a number of environmental variables including temperature, velocity, salinity and suspended sediment load. Ordination was also used to identify associations between species and environmental variables.
Coral boring Aka-species (Porifera: Phloeodictyidae) from Mexico with description of Aka cryptica sp. nov.
Authors: Carballo José Luis , Hepburn Leanne , Nava Héctor H. , Cruz-Barraza José Antonio , Bautista-Guerrero Eric
Published: December 2007

This paper focuses on Aka species boring coral of the East Pacific Ocean and the Caribbean Sea (Mexico). The new species Aka cryptica sp. nov. is described from Mexican Pacific coral reefs, which constitutes the first time that a species of the genus Aka is reported from the East Pacific Ocean. The new species lives cryptically boring coral species of the genus Pocillopora. It is characterized by the small size of their papillae (from 1 to 4.5 mm high and from 0.8 to 1.8 mm in diameter), and oxeas (from 67 to 120 μm), and their exposed parts blend in well with background colours which tend to be overlooked during benthic marine surveys. In addition, Aka coralliphaga and Aka brevitubulata from Mexican Caribbean coral reefs are redescribed. The latter species is reported for the first time in Mexico.
Vertical transmission and successive location of symbiotic bacteria during embryo development and larva formation in Corticium candelabrum (Porifera: Demospongiae)
Authors: de Caralt Sònia , Uriz María J. , Wijffels René H.
Published: December 2007

This study reports on the transfer of heterotrophic bacteria from parental tissue to oocytes in the Mediterranean bacteriosponge Corticium candelabrum (Homosclerophorida) and the description of the successive locations of the microsymbionts during embryo development through transmission and scanning electron microscopy. Eight different types of symbiotic bacteria are described morphologically. These eight bacteria morphotypes are found in both adult individuals and larvae. Symbiotic bacteria are transferred to oocytes, but not to spermatocytes. Bacteria are first located at the oocyte periphery below a thick collagen layer and then they migrate to the oocyte cytoplasm, forming spherical clusters. After cleavage, the bacteria can be found in the free space between blastomeres but mainly accumulate at the embryo periphery below the follicular cells that surround the embryo. Once the blastocoel is formed, the symbiotic bacteria move to this central cavity where they actively divide by bipartition, increasing their number considerably. Many examples of phagocytosed bacteria in the proximal zone of the larval cells are observed at this stage. Consequently, bacteria may represent a complementary source of energy for free larvae and settlers before they are able to capture food from the surrounding water.
Calcareous sponges from São Paulo State, Brazil (Porifera: Calcarea: Calcinea) with the description of two new species
Authors: Lanna Emílio , Rossi André Linhares , Cavalcanti Fernanda F. , Hajdu Eduardo , Klautau Michelle
Published: December 2007

Calcareous sponges (Calcarea: Calcinea) are being described, for the first time, from São Paulo State, Brazil. A total of five species are described, two of which are new to science (Clathrina alcatraziensis sp. nov. and Leucascus roseus sp. nov.). The remaining three species have their distribution widened (Clathrina aurea, C. conifera and C. tetractina).
Evaluation of the quality of two commercial sponges by tensile strength measurement
Authors: Castritsi-Catharios J. , Magli M. , Vacelet J.
Published: December 2007

The aim of this study is to investigate the possibility of using the tensile strength and the elasticity as two, among others, objective criteria for the evaluation of the quality and commercial value of two ‘Elephant Ear’ commercial sponges (Mediterranean and Philippine). These criteria could also provide additional taxonomic characters for the distinction of ill-defined species. The average tensile strength of the Mediterranean Elephant Ear was found equal to 2.88 ±0.19 kg cm-2 and that of the Philippine Elephant Ear equal to 6.88 ±0.77 kg cm-2 while the corresponding values for elasticity were 26.1 ±0.79% and 7.8 ±0.6%. This difference is related to the structure and arrangement of the spongin fibres as seen under the scanning electron microscope. The arrangement of the secondary fibres (very compact and regular structure) as well as the abundance and the orientation of the primary fibres (arrangement in the form of bars perpendicular to the external surface) give to the Philippine Elephant Ear a higher tensile strength value, a roughness to the touch and consequently inelasticity and stiffness. In contrast, the large number of smooth secondary fibres in the Mediterranean Elephant Ear, their loose arrangement and the limited number of primary fibres give to this sponge a higher elasticity and a smaller tensile strength value.
An assessment of sponge mariculture potential in the Spermonde Archipelago, Indonesia
Authors: de Voogd Nicole J.
Published: December 2007

In the present study, carried out in the Spermonde Archipelago, south Sulawesi, Indonesia, an assessment is presented of the farming potential of six sponge species (out of nine candidates considered) possessing pharmacologically promising compounds, i.e. Aaptos suberitoides, Amphimedon paraviridis, Callyspongia (Euplacella) biru, Hyrtios reticulatus, Ircinia ramosa and Pseudoceratina cf. verrucosa. A total of 350 cuttings was threaded on a polyethylene rope and attached to horizontal mooring structures at three experimental sites. Growth and survival were monitored for a period of six months and for some explants for an additional period of ten months. All cuttings were photographed at regular time intervals and growth was measured as increase in length and dry weight. With the exception of P. cf. verrucosa, survival rates were high (80–96%) during the mariculture period. Size increases were too little to be measured in A. suberitoides and P. cf. verrucosa cuttings. Significant growth was only observed for C. biru. The high growth potential and high survival rate of this sponge species suggest that it is a promising candidate for further mariculture development.
Sponges: an historical survey of their knowledge in Greek antiquity
Authors: Voultsiadou Eleni
Published: December 2007

A detailed account of sponge knowledge in Greek antiquity is given on the basis of their records in the written documents of the historical periods it comprises. The analysis of the examined material revealed interesting information on various aspects of sponge biology, more or less consistent with their present scientific knowledge. The value of sponges for man at that time was evident in many of his activities, such as household, personal hygiene, pain relief, disease treatment, art and war enterprises. The significant role of sponges in medical practice is illustrated by the high number of their records in the medical works of the studied historical period. Furthermore, sponges appeared in legends, as well as in similes and metaphors that attributed their special qualities to human behaviour, various body parts or objects.
A new species of Phorbas (Porifera: Poecilosclerida) from the Bellingshausen Sea, Antarctica
Authors: Ríos Pilar , Cristobo Javier
Published: December 2007

Phorbas is a common genus with cosmopolitan distribution. A new species of sponge, Phorbas megasigma sp. nov. (Porifera: Poecilosclerida: Hymedesmiidae) is described from material collected during the third Spanish expedition on the study of the Antarctic benthos, ‘Bentart 03’. Phorbas megasigma is closely related to P. nexus but differs in the possession of arcuate chelae and very big sigmata as microscleres.
Esperiopsis koltuni sp. nov. (Demospongiae: Poecilosclerida: Esperiopsidae), a carnivorous sponge from deep water of the Sea of Okhotsk (North Pacific)
Authors: Ereskovsky Alexander V. , Willenz Philippe
Published: December 2007

Esperiopsis koltuni, a new species of the sponge family Esperiopsidae, is described from deep water of the Sea of Okhotsk. The new species has a unique growth form: there is a basal plate with radiating cylindrical branches, whose oval flat distal parts bear filament-like outgrowths. Megascleres are arranged differently in the main part of branches and in their distal flat parts. The dermal membrane contains isochelae with protruding alae and abundant sigmancistras. Microscleres are represented by large anchorate spatuliferous isochelae, small isochelae, sigmas and sigmancistras. Esperiopsis koltuni sp. nov. is hermaphroditic, with parenchymella larva. The larval skeleton consists only of sigmas and sigmancistras. Esperiopsis koltuni sp. nov. can be easily distinguished from other Esperiopsis species by dimensions and combination of spicule types. In particular, it is the only species in the genus with three different size categories of styles. The new species lacks the aquiferous system, has a characteristic body plan with symmetrical lateral expansions, an unusual arrangement of microscleres in the dermal membrane and true sigmancistras. Moreover, prey capture by a filament-like outgrowth of the flat distal part was observed. All of these characteristics indicate that Esperiopsis koltuni sp. nov. is a carnivorous sponge.
Oxygen dynamics and flow patterns of Dysidea avara (Porifera: Demospongiae)
Authors: Schläppy Marie-Lise , Hoffmann Friederike , Røy Hans , Wijffels René H. , Mendola Dominick , Sidri Marzia , de Beer Dirk
Published: December 2007

The present publication presents oxygen properties and pumping behaviour of Dysidea avara. Oxygen profiles were measured near and inside the atrial space of the osculum with a Clark-type micro-electrode. Pumping sponges had profiles with oxygen concentrations marginally lower than that of the aquarium water. In contrast, diffusive profiles, with a clear boundary layer above the sponge surface, and oxygen penetrating only 0.5 mm into the sponge tissue, were typically that of a sponge which was not pumping. Diffusive oxygen flux at the sponge surface was 4.2 μmol O2 cm2 d1 and the calculated volumetric filtration rate was 0.3 cm3 water cm3 sponge min1. The oxygen concentration in the osculum was temporally fluctuating between 95 and 59% saturation at a frequency of approximately once per minute. The combination of static oxygen micro-electrode measurements and particle tracking velocimetry (PTV) allowed us to simultaneously observe fine-scale oxygen fluxes and oscular flow patterns in active sponges, even at extremely low pumping rates. Oscular oxygen concentration and flow were correlated but not always synchronous to the second. Particle tracking velocimetry was used to visualize the flow field around the sponge and to distinguish sponge-generated flow from the unidirectional current in a flow-cell.
Sponge invaders in Dutch coastal waters
Authors: van Soest Rob W.M. , de Kluijver Mario J. , van Bragt Peter H. , Faasse Marco , Nijland Reindert , Beglinger Elly J. , de Weerdt Wallie H. , de Voogd Nicole J.
Published: December 2007

Continuous monitoring by scientists and volunteers of the Biological Working Group of the Dutch SubAqua Union and the ‘Anemoon’ Foundation over the past four years, yielded a surprising six new records of sponges for Dutch coastal waters. Oscarella lobularis, Celtodoryx girardae, Suberites virgultosus, Haliclona (Haliclona) simulans, Halisarca aff. dujardini, and a species identified as Leucosolenia somesii were unknown from Dutch coastal waters before 2000. The latter is a giant calcareous sponge, seemingly belonging to the common Leucosolenia variabilis, but here assumed to be an invader as well, as it has spicular characters well outside the variation found in the majority of Dutch L. variabilis specimens. It is likely a member of a ‘forgotten’ species, L. somesii. Habit photographs, SEM images of the spicules, and for O. lobularis and H. aff. dujardini, photographs of histological sections are provided to substantiate these new records. With the exception of C. girardae, most of the species resemble previously described widespread north-east Atlantic species, occurring in the area to the south and west of the Netherlands, so it is assumed pending future genetic research that at least several of the invaders comprise range extensions related to rising winter temperatures. Possibly, recent shellfish imports may be an additional causal agent. We also report the occurrence of unprecedented spicular deviations observed in three sponge species commonly occurring in Dutch waters, Halichondria (Halichondria) panicea, Hymeniacidon perlevis and Haliclona (Soestella) xena, which grew in small inland water bodies. Possibly, the limited space in these inland waters with possible stress factors for sponges such as reduced water exchange, and deviating chemistry, have caused the sponges to form stunted growth in spicules varying from rhabds with rounded endings to silica spheroids. We provide an updated list of sponges found in Dutch waters and a list of suspected or proven invaders of Dutch waters.
The ecology of sponges in Lough Hyne Marine Nature Reserve (south-west Ireland): past, present and future perspectives
Authors: Bell James J.
Published: December 2007

Lough Hyne was Europe's first Marine Nature Reserve and is a well known biodiversity hotspot that supports extensive sponge assemblages. The unusual, but predictable, flow and sedimentation regimes have important impacts on the sponge assemblages at the species and assemblage levels. Here I present a review of recent sponge research at Lough Hyne, which covers: (1) a description of the sponge-dominated habitats; (2) the biological and physical factors controlling sponge biodiversity and abundance; (3) sponge species and assemblage level morphological variability; and (4) the relationship between sponge morphological, species and functional diversity. It appears that physical factors are primarily responsible for the sponge diversity and abundance patterns found in Lough Hyne, although the importance of intra- and interphyletic (particularly with algae) competitive interactions requires further investigation. Although our knowledge of how sponges respond and adapt to environmental variability has increased substantially because of the research conducted at Lough Hyne, I have highlighted a number of future research areas in the context of Lough Hyne sponge assemblages, which are relevant to understanding structuring processes across the globe.
Analysis of evolutionary, biogeographical and taxonomic patterns of nucleotide composition in demosponge rRNA
Authors: Erpenbeck Dirk , Cleary Danny F.R. , Voigt Oliver , Nichols Scott A. , Degnan Bernard M. , Hooper John N.A. , Wörheide Gert
Published: December 2007

The ribosome is the location of protein translation and therefore a pivotal macromolecular complex for all organisms. The RNA molecules involved in the formation and functioning of the ribosome (rRNA) are partially single-stranded (loops) and partially double-stranded (helices or stems) as a result of pairing of complementary regions in either their own or other rRNA subunits. This pattern provides the rRNA with a secondary structure crucial for its functionality. The stability of these secondary structures is mediated by their base compositions: a helix rich in G-C pairs possesses a higher thermodynamic stability than an A-T rich counterpart. However, the base composition of these structures is neither homogeneous throughout the molecule nor throughout the demosponge taxa. Here, we present patterns of biased nucleotide composition in demosponge 28S rDNA. We analyse their correlation in respect to environment and taxonomy. We find significantly higher G+C contents in haplosclerid demosponges compared to other orders and investigate evidence for an association between water temperature and rRNA base composition in demosponges.
Incidence and identity of photosynthetic symbionts in Caribbean coral reef sponge assemblages
Authors: Erwin Patrick M. , Thacker Robert W.
Published: December 2007

Marine sponges are abundant and diverse components of coral reefs and commonly harbour photosynthetic symbionts in these environments. The most prevalent symbiont is the cyanobacterium, Synechococcus spongiarum, isolated from taxonomically diverse hosts from geographically distant regions. We combined analyses of chlorophyll-a (chl-a) concentrations with line-intercept transect surveys to assess the abundance and diversity of reef sponges hosting photosymbionts on Caribbean coral reefs in the Bocas del Toro Archipelago, Panamá. To identify symbionts, we designed PCR primers that specifically amplify a fragment of the 16S ribosomal RNA gene from S. spongiarum and used these primers to screen potential host sponges for the presence of this symbiont. Chlorophyll-a data divided the sponge community into two disparate groups, species with high (>125 μg/g, N=20) and low (<50 μg/g, N=38) chl-a concentrations. Only two species exhibited intermediate (50–125 μg/g) chl-a concentrations; these species represented hosts with reduced symbiont populations, including bleached Xestospongia muta and the mangrove form of Chondrilla nucula (C. nucula f. hermatypica). Sponges with high and intermediate chl-a concentrations accounted for over one-third of the species diversity and abundance of sponges in these communities. Most (85%) of these sponges harboured S. spongiarum. Molecular phylogenies reveal that S. spongiarum represents a sponge-specific Synechococcus lineage, distinct from free-living cyanobacteria. The prevalence of sponge–photosymbiont associations and dominance of symbiont communities by S. spongiarum suggest a major role of this cyanobacterium in sponge ecology and primary productivity on coral reefs.
On the phylogenetic relationships of hadromerid and poecilosclerid sponges
Authors: Kober Kord M. , Nichols Scott A.
Published: December 2007

Recent phylogenetic analyses of demosponges have suggested that the order Poecilosclerida is monophyletic and nested within the paraphyletic ‘order’ Hadromerida. Until now, this result has rested upon very limited taxon sampling of SSU sequences and partial LSU sequences. We collected and analysed additional full-length SSU and LSU sequences to test the validity and position of the poecilosclerid/hadromerid clade within demosponges, and we sampled a short segment of the LSU from diverse hadromerids to explore the internal relationships of Hadromerida. Our data strongly support the existence of a hadromerid/poecilosclerid clade that is sister to a poorly characterized group of halichondrid and agelasid species (‘Clade C’). We find support for the monophyly of the hadromerid families Polymastiidae, Placospongiidae and Timeidae, and conditional support for the family Suberitidae. Furthermore, both LSU and SSU data support a clade that includes a mixture of species assigned to the families Tethyidae and Hemiasterellidae (TETH/HEM) and a mixed clade including members of the families Clionaidae and Spirastrellidae (CLIO/SPIR). The family Placospongiidae is reconstructed as sister to the clade CLIO/SPIR and the family Timeidae is supported as sister to the clade TETH/HEM. The order Poecilosclerida is most closely allied with the Placospongiidae/CLIO/SPIR clade.
Where Topsent went wrong: Aka infesta a.k.a. Aka labyrinthica (Demospongiae: Phloeodictyidae) and implications for other Aka spp.
Authors: Schönberg Christine Hanna Lydia , Beuck Lydia
Published: December 2007

Early descriptions for species of Aka were poor in detail, and the only spicule type that occurs in this genus does not vary much between species, which led to taxonomic confusion. Moreover, the type specimens of five species of Aka are lost, causing considerable problems. Mediterranean specimens of Aka were identified as Aka labyrinthica (Hancock, 1849) by Topsent (1900), even though this species was originally described from the Indo-Pacific. All following publications on Mediterranean Aka accepted Topsent's decision. We assessed this problem with new samples from the Ionian Sea. Our material consisted of only one specimen of Aka, and we had to rely mainly on spicule characters for comparison with other species. We developed a system for species recognition solely based on spicular characters and biometry, involving a combination of the parameters oxea length, width, tip form and angle of curvature. This approach was surprisingly accurate. Forming ratios of the above parameters was less helpful, but can sometimes provide additional information. We identified our sample as Aka infesta (Johnson, 1899), and describe it as a minute-fistulate species with large, multicamerate erosion traces and stout, smooth oxeas. Our data further imply that A. labyrinthica sensu Hancock has not yet been found in the Mediterranean. Aka labyrinthica sensu Topsent is a collection of different species not including A. labyrinthica sensu Hancock.
DNA taxonomy of sponges—progress and perspectives
Authors: Wörheide Gert , Erpenbeck Dirk
Published: December 2007

Sponges (Phylum Porifera) are among the most ancestral metazoans and are frequently difficult to identify, even by taxonomic experts, due to their lack of complex morphological characters. However, poriferans are highly diverse, ecologically important and of significant importance to pharmaceutical and biomaterials industries. Therefore, means of unambiguous identification are urgently needed. A DNA taxonomic system, and in particular sponge DNA barcodes, will provide a set of indispensable tools to aid taxonomists and ecologists in the rapid identification of sponge species, which will enhance the discovery of drug-producing species. Here, we will argue for the implementation of a DNA supported taxonomic system and introduce the Sponge Barcoding Project.
Redescription and resurrection of Pachymatisma normani (Demospongiae: Geodiidae), with remarks on the genus Pachymatisma
Authors: Cárdenas Paco , Xavier Joana , Tendal Ole Secher , Schander Christoffer , Rapp Hans Tore
Published: December 2007

An increasing number of cryptic species are being discovered within sponges with assumed wide geographical distribution. Pachymatisma johnstonia (Bowerbank in Johnston, 1842) (Astrophorida: Geodiidae) is one of the most common and known sponges throughout the north-east Atlantic coasts. Pachymatisma normani Sollas, 1888 is a northern species previously synonymized with P. johnstonia by Topsent. It is here redescribed on the basis of fresh material from the type locality, the Korsfjord in the Bergen area (Norway). Spicules are shown to be reliable characters to distinguish the species investigated. Pachymatisma normani is characterized by larger spicules, most markedly in the sterrasters. Our observations also suggest that habitat and gross morphology distinguish P. johnstonia from P. normani. Furthermore, using a partial sequence of the cytochrome c oxidase subunit I (COI) and an ITS1-5.8-ITS2 nuclear fragment, we show that consistent genetic differences exist between the two species. A brief overview of the genus and a key to the known species are also given.
A new species of Stoeba (Demospongiae: Astrophorida) from oceanic islands off north-eastern Brazil
Authors: Moraes Fernando , Muricy Guilherme
Published: December 2007

The genus Stoeba has 11 recognized species. Herein we describe a new species of Stoeba endemic from two oceanic archipelagoes off north-eastern Brazil (Fernando de Noronha and São Pedro e São Paulo), constituting the first record of this genus for the western Atlantic. Stoeba latex sp. nov. is characterized by its thickly encrusting to massive shape, stretched surface, brownish-red colour, and spiculation of calthrops and sanidasters with well developed spines; dichotriaenes and oxeas are absent. Stoeba and Dercitus are very closely related genera, and should probably be merged. The genus Stoeba now contains the following valid species: S. dissimilis, S. exostotica, S. extensa, S. lesinensis, S. natalensis, S. occulta, S. pauper, S. plicata, S. reptans, S. simplex, S. syrmatita and S. latex sp. nov. Several other species still await description. A key to the valid species of Stoeba is given.
Mitochondrial Cytochrome oxidase 1 phylogeny supports alternative taxonomic scheme for the marine Haplosclerida
Authors: Raleigh Jean , Redmond Niamh E. , Delahan Emma , Torpey Seamus , van Soest Rob W.M. , Kelly Michelle , McCormack Grace P.
Published: December 2007

Recent molecular studies have shown that the sponge order Haploslcerida is polyphyletic as the freshwater sponges appear to be more closely related to other demosponges than they are to the marine haplosclerids. Within the marine haplosclerid clade relationships viewed via 18S and 28S rRNA gene phylogenies suggest that the suborders and many families and genera are also polyphyletic. However, both of these genes are on the same locus and do not evolve completely independently. We have analysed mitochondrial Cytochrome oxidase 1 gene fragments from 44 species of marine Haplosclerida and show conclusively that the classification of this group needs complete revision. Molecular data show a very complicated phylogeny supporting very few morphological hypotheses and little geographical pattern. However, the molecular data contain a great deal of phylogenetic signal at many taxonomic levels and support phylogenies drawn from the other genes.
Three new species and one re-description of Aka
Authors: Calcinai Barbara , Cerrano Carlo , Bavestrello Giorgio
Published: December 2007

Three new species of the boring genus Aka, A. coralliirubri, A. microterebrans and A. ruetzleri are described respectively from the Mediterranean Sea, Celebes Sea and Caribbean Sea. The Indo-Pacific A. maldiviensis, known only for the structure of its epilithic fistules, is here described in more detail. The new species confirm that the sponges comprising the genus Aka are able to bore in biogenic substrata only, in particular coral rock, bivalve shells and the scleraxis of the precious coral Corallium. The study of the macroscopic excavation shows that three different patterns can be described: producing discrete boring chambers, large undivided cavities and interconnecting microtunnels giving rise to a spongious aspect of the substratum.
Analysis of intragenomic variation of the rDNA internal transcribed spacers (ITS) in Halichondrida (Porifera: Demospongiae)
Authors: Alvarez Belinda , Krishnan Mahima , Gibb Karen
Published: December 2007

Three species of sponges, Axinella aruensis, Phakellia sp. and Acanthella cavernosa, were selected to investigate the extent of intragenomic variation (IGV) in the internal transcribed spacers (ITS-1 and ITS-2) of the ribosomal DNA within the order Halichondrida. The IGV was detected in both the spacers and in the three species. At least three non-identical sequences were found in any single individual with the number of polymorphic sites within species ranging from 6 to 77. Uncorrected distance values up to 29% were observed in the ITS-2 of Axinella aruensis. The levels of polymorphism found in this species are the highest reported for Porifera and comparable to those observed in hybrid species of scleractinean corals. Analyses of ITS sequences from multiple clones from individuals of Halichondrida are strongly recommended if these genetic markers are to be used to depict phylogenetic and/or phylogeographic relationships of closely related species and their populations. Data from other nuclear and mitochondrial markers should be used to complement conclusions derived from studies based on ITS sequences.
Predation on copepods by an Alaskan cladorhizid sponge
Authors: Watling Les
Published: December 2007

Deep water cladorhizids are now generally thought to be carnivorous. While the methods of prey capture have been established for species of Asbestopluma, and perhaps Chondrocladia, information is sparse for species of Cladorhiza. The external morphology of the deep-sea Alaskan species, Cladorhiza corona, was examined immediately after collection, and then again later using scanning electron microscopy (SEM). All sponges examined had captured, and in most cases, fully encased, prey items which for the most part consisted of planktonic copepods. The hypothesis of this paper is that the primary process of prey capture is by means of a sticky substance and that prey stick to the sponge on contact. The abundant cladorhizid anisochelae do not seem to be arranged in a manner such that they can be used for prey capture as has been seen in Asbestopluma. Digestion of the prey occurs in a temporary cavity created by migrating sponge cells. Within this cavity lipid from the copepod is liberated, then absorbed and transported to the central part of the sponge. It is not known how much of the remaining tissue of the copepod is digested. Copepods have very high lipid content so their capture would provide the sponge with abundant energy from each prey item. The sponges seem to have their highest density in areas where bottom flow and migrating copepod numbers are both high.
Sponge biodiversity
Authors: van Soest R.W.M.
Published: December 2007

Sponges are an integral part of marine benthic communities with a high-impact role in benthic–pelagic coupling processes, as an important source of food for demersal grazers and predators, as hosts of a highly diverse microbial biomass, and as bio-eroders. Sponges provide age-old (hygienic) services to humans and continue to be of interest in modern times as sources of an unprecedented array of useful substances.
Lissodendoryx: rediscovered type and new tropical western Atlantic species (Porifera: Demospongiae: Poecilosclerida: Coelosphaeridae)
Authors: Rützler Klaus , Piantoni Carla , Diaz M. Cristina
Published: December 2007

Seven syntypes of Halichondria isodictyalis, type species of Lissodendoryx, were rediscovered and studied. By choosing a lectotype and studying it along with the paralectotypes, we find that L. isodictyalis, subgenus Lissodendoryx, is a Caribbean sponge characterized by smooth megascleres, ectosomal tylotes and choanosomal styles, and one size-class of microscleres comprising arcuate isochelae and sigmas. Having determined these characteristics, we re-erect Lissodendoryx (Lissodendoryx) carolinensis (previously synonymized with L. isodictyalis), with the same smooth megascleres but two distinct size categories of microscleres, isochelae and sigmas; and we add a new western Atlantic species, Lissodendoryx (L.) spinosa sp. nov., with coarse spines on the megasclere terminals and with two size-classes of isochelae and sigmas. Other species in the region are Lissodendoryx (L.) colombiensis, with smooth tylotes and robust strongyles, and two categories of microscleres (isochelae and sigmas) accompanied by conspicuous raphids arranged in trichodragmas; Lissodendoryx (L.) strongylata, with smooth tylotes and slim strongyles, one size-class each of isochelae and sigmas, rare and very thin raphids. Lissodendoryx sigmata is here assigned to the subgenus Anomodoryx, with smooth tylotes exclusively as megascleres, two size-classes of isochelae, and one or two sizes of sigmas; it may represent a species complex far more diverse than previously thought. To this subgenus we add another species, Lissodendoryx (A.) amphispinulata sp. nov., characterized by fine spines ornamenting both tyles of part of the tylotes. A third subgenus, Ectyodoryx, is represented by Lissodendoryx (E.) acanthostylota sp. nov., with smooth tylotes and finely spined acanthostyles in two size-classes, as well as two size-classes each of isochelae and sigmas as microscleres. All species studied alive occur in shallow lagoon habitats with mangroves and sea grass (Thalassia) but museum specimen records show that some may reach a depth of 60 m.
Five new sponge species (Porifera: Demospongiae) of subtropical or tropical affinities from the coast of Lebanon (eastern Mediterranean)
Authors: Vacelet Jean , Bitar Ghazi , Carteron Sophie , Zibrowius Helmut , Perez Thierry
Published: December 2007

Five new species of sponges are described from the coast of Lebanon in the eastern Mediterranean, Levantine Basin. Euryspongia raouchensis (Dysideidae), Liosina blastifera (Dictyonellidae) and Niphates toxifera (Niphatidae) belong to genera that are new for the Mediterranean but widely distributed in the tropics. Cinachyrella levantinensis (Tetillidae) and Ciocalypta carballoi (Halichondriidae) are described in genera with a restricted distribution in the Mediterranean, which have affinities with species from the Atlantic West African coast. These species do not appear to be lessepsian migrants, but are interpreted as remnants of an ancient thermophilous fauna that survived in the easternmost part of the Mediterranean.
Does sex matter in reintroduction of griffon vulturesGyps fulvus?
Authors: Bosé M. , Le Gouar P. , Arthur C. , Lambourdière J. , Choisy J.P. , Henriquet S. , Lecuyer P. , Richard M. , Tessier C. , Sarrazin F.
Published: December 2007

In small populations of monogamous species sex ratio bias and sex-skewed demographic traits could lead to higher extinction probabilities than in other mating systems. Therefore a knowledge of bias in sex ratio, mortality and movement would be useful to determine the optimal strategy for sampling founders prior to reintroduction. We used molecular sexing to sex wild-hatched cohorts of two colonies (one native and one reintroduced) and four released groups of griffon vulturesGyps fulvusin France. In wild-hatched cohorts the sex ratio was not different from equilibrium whatever the year. Similarly no bias was detected in the sex ratio of founding stocks. Recoveries, recaptures, movements and philopatry were not skewed according to sex in wild-hatched and released groups. Our study revealed that no sex bias occurred during the griffon vulture life cycle (i.e. birth, death and movement). Consequently, random sampling may be appropriate to constitute founding stock in reintroduction programmes for monomorphic vultures.