bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of invertebrate nervous systems: the Chaetognatha as a case study
Authors: Harzsch Steffen , Wanninger Andreas 
Published: December 2009

AbstractHarzsch, S. and Wanninger, A. 2010. Evolution of invertebrate nervous systems: the Chaetognatha as a case study. —Acta Zoologica(Stockholm)91: 35–43Although recent molecular studies indicate that Chaetognatha may be one of the earliest Bilaterian offshoots, the phylogenetic position of this taxon still is a matter of ongoing debate. In this contribution, we review recent attempts to contribute phylogenetic information on the Chaetognatha by analysing structure and development of their nervous system (neurophylogeny). Analysing this group of organisms also has a major impact on our understanding of nervous system evolution in Bilateria. We review recent evidence from this field and suggest that Urbilateria already was equipped with the genetic toolkit required to build a complex, concentrated central nervous system (CNS), although this was not expressed phenotypically so that Urbilateria was equipped with a nerve plexus and not a CNS. This implies that in the deep metazoan nodes, concentration of the ancestral plexus occurred twice independently, namely once after the protostome–deuterostome split on the branch leading to the protostomes (resulting in a ventrally positioned nerve cord) and once along the chordate line (with a dorsal nerve cord).
The organisation of invertebrate brains: cells, synapses and circuits
Authors: Meinertzhagen Ian A. 
Published: December 2009

AbstractMeinertzhagen, I.A. 2010. The organisation of invertebrate brains: cells, synapses and circuits. —Acta Zoologica (Stockholm) 91: 64–71Invertebrate brains are structurally diverse. Neuron numbers range from ∼102 to 108 in different groups, compared with larger numbers in vertebrate brains, ∼107 to 1014. The underpopulated brains of invertebrates are noted in their extreme cases for having few cells, and neurons that can be identified from animal to animal, many known in great detail. Although few in number, invertebrate neurons nevertheless comprise many classes. Correlated with the paucity of their number they are sparsely connected, many having ∼50 synapses or fewer. Synaptic densities, roughly 1 per μm3 of neuropile, differ little from those for much larger vertebrate neurons. Invertebrate neurons differ from their vertebrate counterparts in the position of their soma, generally in a cortex surrounding the neuropile that consequently occupies a relatively small volume. Their axons typically lack myelin and, supporting a range of conduction velocities, have diameters that differ over a wide range, from 103 to 10−1μm. Nerves with thousands of axons differ from neuropile fascicles, which typically have 20 or less. Unlike most vertebrate synapses, but like those of the vertebrate retina, synapses in many invertebrate groups – probably all ecdysozoans and possibly some lophotrochozoans – have synaptic contacts with multiple postsynaptic elements, dyads, triads and so on.
Palaeomorphology: fossils and the inference of cladistic relationships
Authors: Edgecombe Gregory D. 
Published: December 2009

AbstractEdgecombe, G.D. 2010. Palaeomorphology: fossils and the inference of cladistic relationships. —Acta Zoologica (Stockholm) 91: 72–80Twenty years have passed since it was empirically demonstrated that inclusion of extinct taxa could overturn a phylogenetic hypothesis formulated upon extant taxa alone, challenging Colin Patterson’s bold conjecture that this phenomenon ‘may be non‐existent’. Suppositions and misconceptions about missing data, often couched in terms of ‘wildcard taxa’ and ‘the missing data problem’, continue to cloud the literature on the topic of fossils and phylogenetics. Comparisons of real data sets show that no a priori (or indeed a posteriori) decisions can be made about amounts of missing data and most properties of cladograms, and both simulated and real data sets demonstrate that even highly incomplete taxa can impact on relationships. The exclusion of fossils from phylogenetic analyses is neither theoretically nor empirically defensible.
Resistance and biomass in Arabidopsis: a new model for Salicylic Acid perception
Authors: Canet Juan V. , Dobón Albor , Ibáñez Federico , Perales Lorena , Tornero Pablo 
Published: December 2009

SummarySalicylic acid (SA) is an essential hormone for plant defence and development. SA perception is usually measured by counting the number of pathogens that grow in planta upon an exogenous application of the hormone. A biological SA perception model based on plant fresh weight reduction caused by disease resistance in Arabidopsis thaliana is proposed. This effect is more noticeable when a chemical analogue of SA is used, like Benzothiadiazole (BTH). By spraying BTH several times, a substantial difference in plant biomass is observed when compared with the mock treatment. Such difference is dose‐dependent and does not require pathogen inoculation. The model is robust and allows for the comparison of different Arabidopsis ecotypes, recombinant inbreed lines, and mutants. Our results show that two mutants, non‐expresser of pathogenesis‐related genes 1 (npr1) and auxin resistant 3 (axr3), fail to lose biomass when BTH is applied to them. Further experiments show that axr3 responds to SA and BTH in terms of defence induction. NPR1‐related genotypes also confirm the pivotal role of NPR1 in SA perception, and suggest an active program of depletion of resources in the infected tissues.
Learning as immersive experiences: Using the four‐dimensional framework for designing and evaluating immersive learning experiences in a virtual world
Authors: De Freitas Sara , Rebolledo‐Mendez Genaro , Liarokapis Fotis , Magoulas George , Poulovassilis Alexandra 
Published: December 2009

AbstractTraditional approaches to learning have often focused upon knowledge transfer strategies that have centred on textually‐based engagements with learners, and dialogic methods of interaction with tutors. The use of virtual worlds, with text‐based, voice‐based and a feeling of ‘presence’ naturally is allowing for more complex social interactions and designed learning experiences and role plays, as well as encouraging learner empowerment through increased interactivity. To unpick these complex social interactions and more interactive designed experiences, this paper considers the use of virtual worlds in relation to structured learning activities for college and lifelong learners. This consideration necessarily has implications upon learning theories adopted and practices taken up, with real implications for tutors and learners alike. Alongside this is the notion of learning as an ongoing set of processes mediated via social interactions and experiential learning circumstances within designed virtual and hybrid spaces. This implies the need for new methodologies for evaluating the efficacy, benefits and challenges of learning in these new ways. Towards this aim, this paper proposes an evaluation methodology for supporting the development of specified learning activities in virtual worlds, based upon inductive methods and augmented by the four‐dimensional framework reported in a previous study.The study undertaken aimed to test the efficacy of the proposed evaluation methodology and framework, and to evaluate the broader uses of a virtual world for supporting lifelong learners specifically in their educational choices and career decisions. The paper presents the findings of the study and considers that virtual worlds are reorganising significantly how we relate to the design and delivery of learning. This is opening up a transition in learning predicated upon the notion of learning design through the lens of ‘immersive learning experiences’ rather than sets of knowledge to be transferred between tutor and learner. The challenges that remain for tutors rest with the design and delivery of these activities and experiences. The approach advocated here builds upon an incremental testing and evaluation of virtual world learning experiences.
A multi‐user virtual environment for building and assessing higher order inquiry skills in science
Authors: Ketelhut Diane Jass , Nelson Brian C. , Clarke Jody , Dede Chris 
Published: December 2009

AbstractThis study investigated novel pedagogies for helping teachers infuse inquiry into a standards‐based science curriculum. Using a multi‐user virtual environment (MUVE) as a pedagogical vehicle, teams of middle‐school students collaboratively solved problems around disease in a virtual town called River City. The students interacted with ‘avatars’ of other students, digital artefacts and computer‐based ‘agents’ acting as mentors and colleagues in a virtual community of practice set during the time period when bacteria were just being discovered. This paper describes the results from three implementations of the River City virtual environment in 2004–05 with approximately 2000 students from geographically diverse urban areas. The results indicated that students were able to conduct inquiry in virtual worlds and were motivated by that process. However, the results from the assessments varied depending on the assessment strategy employed.
Multi‐Perspective Modelling, Rendering and Imaging
Authors: Yu J. , McMillan L. , Sturm P. 
Published: December 2009

AbstractA perspective image represents the spatial relationships of objects in a scene as they appear from a single viewpoint. In contrast, a multi‐perspective image combines what is seen from several viewpoints into a single image. Despite their incongruity of view, effective multi‐perspective images are able to preserve spatial coherence and can depict, within a single context, details of a scene that are simultaneously inaccessible from a single view, yet easily interpretable by a viewer. In computer vision, multi‐perspective images have been used for analysing structure revealed via motion and generating panoramic images with a wide field‐of‐view using mirrors.In this STAR, we provide a practical guide on topics in multi‐perspective modelling and rendering methods and multi‐perspective imaging systems. We start with a brief review of multi‐perspective image techniques frequently employed by artists such as the visual paradoxes of Escher, the Cubism of Picasso and Braque and multi‐perspective panoramas in cel animations. We then characterize existing multi‐perspective camera models, with an emphasis on their underlying geometry and image properties. We demonstrate how to use these camera models for creating specific multi‐perspective rendering effects. Furthermore, we show that many of these cameras satisfy the multi‐perspective stereo constraints and we demonstrate several multi‐perspective imaging systems for extracting 3D geometry for computer vision.The participants learn about topics in multi‐perspective modelling and rendering for generating compelling pictures for computer graphics and in multi‐perspective imaging for extracting 3D geometry for computer vision. We hope to provide enough fundamentals to satisfy the technical specialist without intimidating curious digital artists interested in multi‐perspective images.The intended audience includes digital artists, photographers and computer graphics and computer vision researchers using or building multi‐perspective cameras. They will learn about multi‐perspective modelling and rendering, along with many real world multi‐perspective imaging systems.
Animal behaviour and marine protected areas: incorporating behavioural data into the selection of marine protected areas for an endangered killer whale population
Authors: Ashe E. , Noren D. P. , Williams R. 
Published: December 2009

AbstractLike many endangered wildlife populations, the viability and conservation status of ‘southern resident’ killer whalesOrcinus orcain the north‐east Pacific may be affected by prey limitation and repeated disturbance by human activities. Marine protected areas (MPAs) present an attractive option to mitigate impacts of anthropogenic activities, but they run the risk of tokenism if placed arbitrarily. Notwithstanding recreational and industrial marine traffic, the number of commercial vessels in the local whalewatching fleet is approaching the number of killer whales to be watched. Resident killer whales have been shown to be more vulnerable to vessel disturbance while feeding than during resting, travelling or socializing activities, therefore protected‐areas management strategies that target feeding ‘hotspots’ should confer greater conservation benefit than those that protect habitat generically. Classification trees and spatially explicit generalized additive models were used to model killer whale habitat use and whale behaviour in inshore waters of Washington State (USA) and British Columbia (BC, Canada). Here we propose a candidate MPA that is small (i.e. a few square miles), but seemingly important. Killer whales were predicted to be 2.7 times as likely to be engaged in feeding activity in this site than they were in adjacent waters. A recurring challenge for cetacean MPAs is the need to identify areas that are large enough to be biologically meaningful while being small enough to allow effective management of human activities within those boundaries. Our approach prioritizes habitat that animals use primarily for the activity in which they are most responsive to anthropogenic disturbance.
Using probabilistic models to investigate the disappearance of a widespread frog‐species complex in high‐altitude regions of south‐eastern Australia
Authors: Hamer A. J. , Lane S. J. , Mahony M. J. 
Published: December 2009

AbstractAmphibian populations have suffered declines and disappearances around the world. It is now recognized that many of the disappearances were the result of infection by the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). Most global declines were first observed in the 1980s. Here, we used information from museum collections, natural‐history databases and the literature to quantitatively assess the disappearance of the bell frog species complex (Litoria aurea, Litoria castanea and Litoria raniformis) in high‐altitude Tableland regions of the Great Dividing Range, south‐eastern Australia. Based on the sighting record, we estimated that Li. castanea disappeared on the Northern Tablelands in 1979, then from the Southern and Central Tablelands in 1984. Estimated dates of disappearance of Li. aurea and Li. raniformis from the Southern and Central Tablelands were 1981 and 1982, respectively. The Northern Tablelands populations of Li. castanea may have been one of the first high‐altitude populations of frogs to disappear from Australasia and perhaps one of the first globally. We documented targeted searches of suitable habitat within the historic range of the three species in these Tableland regions since 1985, noting that only one bell frog population was discovered (Li. aurea, Southern Tablelands, 2000). Our Solow equation estimate of the probability of extant populations of bell frogs persisting up to the year 2000 was <0.001, so the rediscovery of Li. aurea was mathematically exceptional. Although the cause of these declines remains unknown, the latitudinal (i.e. north to south) and rapid pattern of disappearance of Li. castanea, and the rapid contraction in the range of Li. aurea and Li. raniformis from high‐altitude regions, strongly suggests a pathogen such as Bd was responsible. We recommend further surveys for bell frogs on the Tablelands, as the rediscovery of Li. aurea provides faint hope of finding other extant populations.
Deep evolutionary roots of strepsirrhine primate labyrinthine morphology
Authors: Lebrun Renaud , De León Marcia P. , Tafforeau Paul , Zollikofer Christoph 
Published: December 2009

AbstractThe cavity system of the inner ear of mammals is a complex three‐dimensional structure that houses the organs of equilibrium and hearing. Morphological variation of the inner ear across mammals reflects differences in locomotor behaviour and hearing performance, and the good preservation of this structure in many fossil specimens permits analogous inferences. However, it is less well known to what extent the morphology of the bony labyrinth conveys information about the evolutionary history of primate taxa. We studied this question in strepsirrhine primates with the aim to assess the potential and limitations of using the inner ear as a phylogenetic marker. Geometric morphometric analysis showed that the labyrinthine morphology of extant strepsirrhines contains a mixed locomotor, allometric and phylogenetic signal. Discriminant analysis at the family level confirmed that labyrinthine shape is a good taxonomic marker. Our results support the hypothesis that evolutionary change in labyrinthine morphology is adequately described with a random walk model, i.e. random phenotypic dispersal in morphospace. Under this hypothesis, average shapes calculated for each node of the phylogenetic tree give an estimate of inner ear shapes of the respective last common ancestors (LCAs), and this information can be used to infer character state polarity. The labyrinthine morphology of the fossil Adapinae is close to the inferred basal morphology of the strepsirrhines. The inner ear of Daubentonia, one of the most derived extant strepsirrhines, is autapomorphic in many respects, but also presents unique similarities with adapine labyrinths.
Utilization of medical healthcare among people receiving long‐term care at home or in special accommodation
Authors: Condelius Anna , Edberg Anna‐Karin , Hallberg Ingalill Rahm , Jakobsson Ulf 
Published: December 2009

Scand J Caring Sci; 2010; 24; 404–413 Utilization of medical healthcare among people receiving long‐term care at home or in special accommodationAim: To investigate the utilization of medical healthcare, hospital care and outpatient care, during a 1‐year period in relation to informal care, multimorbidity, functional status and health complaints and to long‐term care at home or in special accommodation among people aged 65+, with one or more hospital admissions and receiving long‐term care.Method: A total of 694 people receiving long‐term care during the year 2001 were studied. Data were collected by means of the administrative registers Patient Administrative Support in Skåne and PrivaStat and through the study Good Ageing in Skåne. Those at home and those in special accommodation were compared regarding utilization of medical healthcare, informal care, multimorbidity, functional status and health complaints. Multiple logistic regression analysis was performed using at home vs. in special accommodation as the dependent variable and also two multiple linear regression analyses using the number of hospital stays and the number of contacts with the physician in outpatient care separately as dependent variables.Findings: Those at home were significantly younger (mean age: 81 vs. 84 years) and less dependent in personal and instrumental activities of daily living (PADL/IADL) than those in special accommodation. A larger proportion of those at home was admitted to hospital three times or more (21 vs. 14%) and they had significantly more contacts with physicians in outpatient care (md: 10 vs. md: 7). Informal care was associated with care at home (OR = 0.074) and with utilization of outpatient care (B = 2.045). Dependency in PADL was associated with care in special accommodation (OR = 1.375) and with utilization of hospital care (B = −0.060) and outpatient care (B = −0.581).Conclusion: Medical healthcare seems more accessible to those who live at home are younger, less dependent and who have access to informal caregivers.
The Primary Headaches as a Reflection of Genetic Darwinian Adaptive Behavioral Responses
Authors: Montagna Pasquale , Pierangeli Giulia , Cortelli Pietro 
Published: December 2009

(Headache2010;50:273‐289)Objective.—The objective of this study is to present a view of the primary headaches as genetically determined behavioral responses consistent with sickness behavior and defense reaction, respectively.Background and Design.—A review of the literature bearing on the behavioral, humoral, and functional imaging aspects of the primary headaches shows that migraine and cluster headache (CH) are pain conditions characterized by different behaviors during the attacks. Here it is postulated that the behavioral responses to migraine and CH are evolutionary conserved reactions consistent with sickness behavior and defense reaction.Results.—The sickness behavior observed during migraine attacks is a pan‐mammalian adaptive response to internal and external stressors, characterized by withdrawal and motor quiescence, sympatho‐inhibition and lethargy, in which visceral pain signals a homeostatic imbalance of the body and/or brain. In contrast, the defense reaction in CH consists of a fight‐or‐flight reaction, with motor restlessness and agitation, in which pain is exteroceptive in kind.Conclusion.—These different behavioral responses are thus specific to different kinds of pain, distinguished by the behavioral significance of the pain (visceral pain in migraine vs exteroceptive pain in CH), and imply brain matrices involving different networks in the brainstem, hypothalamus, and forebrain regions that engender evolutionarily conserved adaptive genetic responses. Cytokines play an important role in their development. Predictions and limitations of the hypothesis are discussed together with implications for genetic studies on headaches.
The “Repeater” Phenomenon in Migraine Patients: A Clinical and Psychometric study
Authors: Villani Veronica , Di Stani Fabrizio , Vanacore Nicola , Scattoni Lorena , Cerbo Rosanna , Bruti Gianluca 
Published: December 2009

(Headache 2010;50:348‐356)Background.— Headache is one of the most common symptoms in an emergency department (ED), while migraine is the most frequently observed headache in this setting. The aim of our study was to evaluate the influence of clinical and psychometric variables on the repeater phenomenon, ie, patients who make at least 3 visits to the ED at least 1 week apart during a 6‐month period.Methods.— According to the International Classification of Headache Disorders, 2nd edition (ICHD‐II) criteria, we consecutively recruited Italian‐speaking migraine subjects who came to the ED or outpatient service. All the patients underwent the Migraine Disability Assessment Scale for the evaluation of migraine disability. We also administered the Beck Depression Inventory, State and Trait Anxiety Inventory, and Toronto Alexithymia Scale‐20 for the evaluation of depressive, anxiety, and alexithymic symptoms, respectively. A personality profile was also obtained by means of the Tridimensional Personality Questionnaire (TPQ).Results.— We consecutively enrolled 465 migraine patients, diagnosed according to the ICHD‐II criteria. Seventy (15%) of these patients met the repeater definition. The repeater group had more severe disability and was affected to a greater degree by chronic migraine, regardless of symptomatic drug overuse, than the non‐repeater group. As regards the psychometric variables, repeaters were more alexithymic, anxious, and depressed than non‐repeaters. The personality profile, as measured by the TPQ, revealed that the repeater patients scored higher on the harm avoidance scale and their subscales than the non‐repeater patients.Conclusions.— According to the findings of our study, the repeater migraineur is typically triptan‐naïve, more alexithymic, and more depressed than the non‐repeater migraineur. A clinical and psychometric evaluation of repeater patients who go to the ED because of migraine attacks may help to understand this epidemiological and clinical phenomenon. From a clinical point of view, these psychometric findings may not only shed light on the epidemiology of migraine in the ED, but may also help to design a specific therapeutic protocol for this subgroup of migraine patients.