Dissociation between skin conductance orienting and secondary task reaction time: Time course with a visual discrimination task

A dissociation between two putative measures of resource allocation skin conductance responding, and secondary task reaction time (RT), has been observed during auditory discrimination tasks. Four experiments investigated the time course of the dissociation effect with a visual discrimination task. participants were presented with circles and ellipses and instructed to count the number of longer-than-usual presentations of one shape (task-relevant) and to ignore presentations of the other shape (task-irrelevant). Concurrent with this task, participants made a speeded motor response to an auditory probe. Experiment 1 showed that skin conductance responses were larger during task-relevant stimuli than during task-irrelevant stimuli, whereas RT to probes presented at 150 ms following shape onset was slower during task-irrelevant stimuli. Experiments 2 to 4 found slower RT during task-irrelevant stimuli at probes presented at 300 ms before shape onset until 150 ms following shape onset. At probes presented 3,000 and 4,000 ms following shape onset probe RT was slower during task-relevant stimuli. The similarities between the observed time course and the so-called psychological refractory period (PRF) effect are discussed.

A systemic secondary vessel system is present in the teleost fish Tandanus tandanus and absent in the elasmobranchs Carcharhinus melanopterus and Rhinobutos typus and in the dipnoan Neoceratodus forsteri

A system of secondary vessels emerging from the primary vessels as numerous coiled capillaries has been described in numerous teleost and holost fishes. The systemic secondary vessels of the teleost Tandanus tandanus are typical of this system and are described in this study. The existence of a secondary vessel system has been postulated in the elasmobranch group. No secondary vessel origins, as seen in the teleosts, are present in the elasmobranchs Rhinobatos typus and Carcharhinus melanopterus. Vessels with a similar distribution to secondary arteries are observed but these are venous rather than arterial in nature and do not connect with the primary arteries. Like the secondary veins in teleosts, the cutaneous veins in R. typus contain blood with a low haematocrit. There is no morphological evidence for a secondary vessel system in the dipnoan Neoceratodus forsteri.

Determining forest structural attributes using an inverted geometric-optical model in mixed eucalypt forests, Southeast Queensland, Australia

The Montreal Process indicators are intended to provide a common framework for assessing and reviewing progress toward sustainable forest management. The potential of a combined geometrical-optical/spectral mixture analysis model was assessed for mapping the Montreal Process age class and successional age indicators at a regional scale using Landsat Thematic data. The project location is an area of eucalyptus forest in Emu Creek State Forest, Southeast Queensland, Australia. A quantitative model relating the spectral reflectance of a forest to the illumination geometry, slope, and aspect of the terrain surface and the size, shape, and density, and canopy size. Inversion of this model necessitated the use of spectral mixture analysis to recover subpixel information on the fractional extent of ground scene elements (such as sunlit canopy, shaded canopy, sunlit background, and shaded background). Results obtained fron a sensitivity analysis allowed improved allocation of resources to maximize the predictive accuracy of the model. It was found that modeled estimates of crown cover projection, canopy size, and tree densities had significant agreement with field and air photo-interpreted estimates. However, the accuracy of the successional stage classification was limited. The results obtained highlight the potential for future integration of high and moderate spatial resolution-imaging sensors for monitoring forest structure and condition. (C) Elsevier Science Inc., 2000.

Discriminating between task-relevant and task-irrelevant stimuli - The effects on autonomic orienting and secondary task reaction time

The effect that the difficulty of the discrimination between task-relevant and task-irrelevant stimuli has on the relationship between skin conductance orienting and secondary task reaction time (RT) was examined. Participants (N = 72) counted the number of longer-than-usual presentations of one shape (task-relevant) and ignored presentations of another shape (task-irrelevant). The difficulty of discriminating between the two shapes varied across three groups (low, medium, and high difficulty). Simultaneous with the primary counting task, participants performed a secondary RT task to acoustic probes presented 50, 150, and 2000 ms following shape onset. Skin conductance orienting was larger, and secondary RT at the 2000 ms probe position was slower during task-relevant shapes than during task-irrelevant shapes in the low-difficulty group. This difference declined as the discrimination difficulty was increased, such that there was no difference in the high-difficulty group. Secondary RT was slower during task-irrelevant shapes than during task-relevant shapes only in the medium-difficulty group-and only at the 150 ms probe position in the first half of the experiment. The close relationship between autonomic orienting and secondary RT at the 2000 ms probe position suggests that orienting reflects the resource allocation that results from the number of matching features between a stimulus input and a mental representation primed as significant.

The secondary vascular system of Actinopterygii: interspecific variation in origins and investment

Vascular casts of 3 species of Chondrichthyes, 1 of Dipnoi, 1 of Chondrostei and 14 species of the Teleostei were examined by light and scanning electron microscopy in order to give a qualitative and quantitative analysis of interarterial anastomoses (iaas) that indicate the presence (or absence) of a secondary vascular system (SVS). Anastomoses were found to originate from a variety of different primary blood vessels, many of which have not been previously identified as giving rise to secondary vessels. Segmental arteries derived from the dorsal aorta and supplying body musculature were major sites of origin of the SVS, although there was considerable variation in where, in the hierarchy of arterial branching, the anastomoses occurred. The degree of investment in a SVS was species specific, with more active species having a higher degree of secondary vascularisation. This difference was quantified using an absolute count of iaas between Anguilla reinhardtii and Trachinotus baillonii. A range of general features of the SVS is also described. No evidence of iaas was found on the coeliac, mesenteric or renal circulation in any species. Evidence of iaas was lacking in the dipnoan and chondrichthyan species examined, suggesting that a SVS is restricted to Actinopterygii. The presence and distribution of a SVS does not appear to be exclusively linked to phylogenetic position, but rather to the physiological adaptation of the species.

Equine laminitis: loss of hemidesmosomes in hoof secondary epidermal lamellae correlates to dose in an oligofructose induction model: an ultrastructural study

Reasons for performing study: Light microscopical studies show that the key lesion of laminitis is separation at the hoof lamellar dermal-epidermal interface. More precise knowledge of the damage occurring in the lamellar basement membrane zone may result if laminitis affected tissue is examined with the transmission electron microscope. This could lead to better understanding of the pathogenesis of lesions and the means of treatment or prevention. Objectives: To investigate the ultrastructure of acute laminitis as disease of greater severity is induced by increasing oligofructose (OF) dosage. Methods: Three pairs of normal horses, dosed with OF at 7.5, 10 and 12.5 g/kg bwt via nasogastric intubation, developed laminitis 48 h later. Following euthanasia, their forefeet were processed for transmission electron microscopy. Lamellar basal cell hemidesmosome (HD) numbers and the distance between the basal cell plasmalemma and the lamina densa of the basement membrane were estimated and compared to control tissue. Results: Increasing OF dosage caused greater HD loss and more severe laminitis. The characteristic separation of the basement membrane, cytoskeleton failure and rounded basal cell nuclei results from combined HD dysassembly and anchoring filament failure. Conclusions: Without properly assembled HDs, dysadhesion between the lamina densa of the basement membrane (BM) and epidermal basal cells occurs, emphasising the fundamental importance of HDs in maintaining attachment at the lamellar interface. Medical conditions that trigger lamellar matrix metalloproteinase (MMP) activation and/or compromise entry of glucose into lamellar basal cells appear to promote loss and failure of HDs and, therefore, laminitis development. Potential relevance: A correlation between lameness severity and escalating loss of lamellar HDs now exists. Therapy aimed at protecting the lamellar environment from haematogenous delivery of MMP activators or from glucose deprivation may control laminitis development.

Ecosystem process models at multiple scales for mapping tropical forest productivity

Quantifying mass and energy exchanges within tropical forests is essential for understanding their role in the global carbon budget and how they will respond to perturbations in climate. This study reviews ecosystem process models designed to predict the growth and productivity of temperate and tropical forest ecosystems. Temperate forest models were included because of the minimal number of tropical forest models. The review provides a multiscale assessment enabling potential users to select a model suited to the scale and type of information they require in tropical forests. Process models are reviewed in relation to their input and output parameters, minimum spatial and temporal units of operation, maximum spatial extent and time period of application for each organization level of modelling. Organizational levels included leaf-tree, plot-stand, regional and ecosystem levels, with model complexity decreasing as the time-step and spatial extent of model operation increases. All ecosystem models are simplified versions of reality and are typically aspatial. Remotely sensed data sets and derived products may be used to initialize, drive and validate ecosystem process models. At the simplest level, remotely sensed data are used to delimit location, extent and changes over time of vegetation communities. At a more advanced level, remotely sensed data products have been used to estimate key structural and biophysical properties associated with ecosystem processes in tropical and temperate forests. Combining ecological models and image data enables the development of carbon accounting systems that will contribute to understanding greenhouse gas budgets at biome and global scales.

Four new species of Paratrizygia Tonnoir from the Brazilian Atlantic Forest (Diptera, Mycetophilidae, Sciophilinae)

Paratrizygia Tonnoir was originally described for P. conformis, from Australia, and since then only four species have been added to the genus, from Chile and Southern Argentina. We add four new species to the genus Paratrizygia-P. balbii sp. nov., P. alvesi sp. nov., P. camargoi sp. nov., and P. albidens sp.nov.-from the southern part of the Brazilian Atlantic Forest. Comments are made about the possible relationships of the Brazilian and other Neotropical species of the genus. An identification key to the Neotropical species of the genus is provided.

Five new species of Coniceromyia Borgmeier (Diptera: Phoridae) from the Atlantic Forest, Brazil

Five new species of Coniceromyia from the Atlantic Forest in Brazil are herein described-Coniceromyia apechoneura, sp. nov., C. brandaoi, sp. nov., C. diaphaniptera, sp. nov., C. franciscana, sp. nov., and C. sanctaetheresae, sp. nov. Both C. diaphaniptera and C. franciscana have patterned wings. The male foretibia provides important diagnostic features for the species, as well as additional characters to propose clades within the genus. The male hypopygial morphology is described.

A new species of Almeidea (Galipeinae, Galipeeae, Rutaceae) from Eastern Brazil

A new species of Almeidea (Rutaceae) belonging to the neotropical tribe Galipeeae (subtribe Galipeinae) is described and illustrated. This new species, Almeidea albiflora, is known so far only from a few collections made in small disturbed forest remnants in the vicinity of Cachoeiro de Itapemirim, in the state of Espirito Santo, and by a single collection from northern Rio de Janeiro state, both in the domain of the Atlantic Forest, Eastern Brazil. Diagnostic features, like white petals, sericeous ovary and distal secondary axes as long as the proximal ones are identified. Pollen morphology is also described, and brief discussions of the relationships of the new taxon to other species of Almeidea, as well as comments on its conservation status, are provided.

Phylogeography of the cactophilic species Drosophila gouveai: demographic events and divergence timing in dry vegetation enclaves in eastern Brazil

Aim The aim of this study was to assess the causal mechanisms underlying populational subdivision in Drosophila gouveai, a cactophilic species associated with xeric vegetation enclaves in eastern Brazil. A secondary aim was to investigate the genetic effects of Pleistocene climatic fluctuations on these environments. Location Dry vegetation enclaves within the limits of the Cerrado domain in eastern Brazil. Methods We determined the mitochondrial DNA haplotypes of 55 individuals (representing 12 populations) based on sequence data of a 483-bp fragment from the cytochrome c oxidase subunit II (COII) gene. Phylogenetic and coalescent analyses were used to test for the occurrence of demographic events and to infer the time of divergence amongst genetically independent groups. Results Our analyses revealed the existence of two divergent subclades (G1 and G2) plus an introgressed clade restricted to the southernmost range of D. gouveai. Subclades G1 and G2 displayed genetic footprints of range expansion and segregated geographical distributions in south-eastern and some central highland regions, east and west of the Parana River valley. Molecular dating indicated that the main demographic and diversification events occurred in the late to middle Pleistocene. Main conclusions The phylogeographical and genetic patterns observed for D. gouveai in this study are consistent with changes in the distribution of dry vegetation in eastern Brazil. All of the estimates obtained by molecular dating indicate that range expansion and isolation pre-dated the Last Glacial Maximum, occurring during the late to middle Pleistocene, and were probably triggered by climatic changes during the Pleistocene. The current patchy geographical distribution and population subdivision in D. gouveai is apparently closely linked to these past events.

Four new species of Paraclius Loew (Diptera: Dolichopodidae) from the Brazilian Atlantic Forest, and notes on the systematic position of Cheiromyia Dyte

Four new species of Paraclius Loew from the Brazilian Atlantic Forest are described and illustrated: P. amphiatheratus, sp. nov., P. parenti, sp. nov., P. sagittatus, sp. nov., and P. dicrophallus, sp. nov. The condition of their enlarged sperm pump, also seen in the Neotropical genus Cheiromyia Dyte, is briefly discussed. Comments on the phylogenetic position of Cheiromyia are presented in light of new data from female terminalia of that genus.

Morphological and morphometric appraisal of the spermatophore of the southern hermit crab Isocheles sawayai Forest and Saint Laurent, 1968 (Anomura: Diogenidae), with comments on gonopores in both sexes

The spermatophore morphology of the hermit crab Isocheles sawayai from Southwestern Atlantic (Brazil) is described. The spermatophores show similarities with those described for other members of the family Diogenidae, especially with the recently described Loxopagurus loxochelis. The spermatophore is composed of three major regions: a sperm filled head or ampulla, a columnar stalk and a foot or pedestal. The spermatophores show specific morphology in having a circular ampulla, and a constriction or neck between the ampulla (100 mu m) and the thin (27 mu m), long stalk (500 mu m). The stalk penetrates less than half way into the spermatophore head. Most spermatophores show one or the small posterior projections on the underside of the ampulla as being bigger than the other, making it asymmetrical. The size of the spermatophore is related to hermit crab size with direct relationships found between spermatophore ampulla width, total length, and peduncle length with shield length of the hermit crab. The morphological characteristics of the spermatophore of L sawayai. are species-specific distinguishing it from other members of the family, and are useful to infer further phylogenetic relationships. (C) 2008 Elsevier GmbH. All rights reserved.

Eleven new species of the genus Cluzobra Edwards (Diptera, Mycetophilidae, Sciophilinae) from the Atlantic Forest of Brazil

Eleven new species of the sciophiline genus Cluzobra Edwards are described and illustrated - Cluzobra triocellata, sp.n., Cluzobra accola, sp.n., Cluzobra claripennis, sp.n., Cluzobra papaveroi, sp.n., Cluzobra coptolithus, sp.n., Cluzobra vockerothi, sp.n., Cluzobra sapiranga, sp.n., Cluzobra fluminense, sp.n., Cluzobra fritzmuelleri, sp.n., Cluzobra spinata, sp.n., Cluzobra elpidia, sp.n. Additional specimens of C. fuscipennis Edwards, C. plaumanni Edwards, and C. binocellaris (Edwards) have been identified, extending the distribution range of these species. The species were identified and described based on 173 specimens at different latitudes along the Atlantic Forest in eastern Brazil and northern Argentina. The position of the new species in the groups of species proposed for the genus in the literature is considered. Three areas of endemism are identified for the group, one from southern Brazil, northern Argentina and Paraguay northwards to areas at higher altitudes in the States of Minas Gerais and Rio de Janeiro, one from southern Bahia to the extreme north of the Atlantic Forest, in the State of Rio Grande do Norte, and one in west State of Sao Paulo, extending west and northwards into the states of Mato Grosso do Sul and Goias. This paper raises the number of known Cluzobra to 41 species.