Using Different Methods to Access the Difficult Task of Delimiting Species in a Complex Neotropical Hyperdiverse Group

The genus Rineloricaria is a Neotropical freshwater fish group with a long and problematic taxonomic history, attributed to the large number of species and the pronounced similarity among them. In the present work, taxonomic information and different molecular approaches were used to identify species boundaries and characterize independent evolutionary units. We analyzed 228 samples assembled in 53 distinct morphospecies. A general mixed yule-coalescent (GMYC) analysis indicated the existence of 70 entities, while BOLD system analyses showed the existence of 56 distinct BINs. When we used a new proposed integrative taxonomy approach, mixing the results obtained by each analysis, we identified 73 OTUs. We suggest that Rineloricaria probably has some complexity in the known species and several species not formally described yet. Our data suggested that other hyperdiverse fish groups with wide distributions can be further split into many new evolutionary taxonomic units.     

Motor Imagery in Asperger Syndrome: Testing Action Simulation by the Hand Laterality Task

Asperger syndrome (AS) is a neurodevelopmental condition within the Autism Spectrum Disorders (ASD) characterized by specific difficulties in social interaction, communication and behavioural control. In recent years, it has been suggested that ASD is related to a dysfunction of action simulation processes, but studies employing imitation or action observation tasks provided mixed results. Here, we addressed action simulation processes in adolescents with AS by means of a motor imagery task, the classical hand laterality task (to decide whether a rotated hand image is left or right); mental rotation of letters was also evaluated. As a specific marker of action simulation in hand rotation, we assessed the so-called biomechanical effect, that is the advantage for judging hand pictures showing physically comfortable versus physically awkward positions. We found the biomechanical effect in typically-developing participants but not in participants with AS. Overall performance on both hand laterality and letter rotation tasks, instead, did not differ in the two groups. These findings demonstrated a specific alteration of motor imagery skills in AS. We suggest that impaired mental simulation and imitation of goal-less movements in ASD could be related to shared cognitive mechanisms.     

Very Slow Search and Reach: Failure to Maximize Expected Gain in an Eye-Hand Coordination Task

We examined an eye-hand coordination task where optimal visual search and hand movement strategies were inter-related. Observers were asked to find and touch a target among five distractors on a touch screen. Their reward for touching the target was reduced by an amount proportional to how long they took to locate and reach to it. Coordinating the eye and the hand appropriately would markedly reduce the search-reach time. Using statistical decision theory we derived the sequence of interrelated eye and hand movements that would maximize expected gain and we predicted how hand movements should change as the eye gathered further information about target location. We recorded human observers'' eye movements and hand movements and compared them with the optimal strategy that would have maximized expected gain. We found that most observers failed to adopt the optimal search-reach strategy. We analyze and describe the strategies they did adopt.     

Using Fiction to Assess Mental State Understanding: A New Task for Assessing Theory of Mind in Adults

Social functioning depends on the ability to attribute and reason about the mental states of others – an ability known as theory of mind (ToM). Research in this field is limited by the use of tasks in which ceiling effects are ubiquitous, rendering them insensitive to individual differences in ToM ability and instances of subtle ToM impairment. Here, we present data from a new ToM task – the Short Story Task (SST) - intended to improve upon many aspects of existing ToM measures. More specifically, the SST was designed to: (a) assess the full range of individual differences in ToM ability without suffering from ceiling effects; (b) incorporate a range of mental states of differing complexity, including epistemic states, affective states, and intentions to be inferred from a first- and second-order level; (c) use ToM stimuli representative of real-world social interactions; (d) require participants to utilize social context when making mental state inferences; (e) exhibit adequate psychometric properties; and (f) be quick and easy to administer and score. In the task, participants read a short story and were asked questions that assessed explicit mental state reasoning, spontaneous mental state inference, and comprehension of the non-mental aspects of the story. Responses were scored according to a rubric that assigned greater points for accurate mental state attributions that included multiple characters’ mental states. Results demonstrate that the SST is sensitive to variation in ToM ability, can be accurately scored by multiple raters, and exhibits concurrent validity with other social cognitive tasks. The results support the effectiveness of this new measure of ToM in the study of social cognition. The findings are also consistent with studies demonstrating significant relationships among narrative transportation, ToM, and the reading of fiction. Together, the data indicate that reading fiction may be an avenue for improving ToM ability.     

Sensory System Affects Orientational Strategy in a Short-Range Spatial Task in Blind and Eyed Morphs of the Fish, Astyanax fasciatus

In the concerted effort to discover the mechanisms that animals use to orient through space, little attention has been given to the role of the sensory system on shaping orientational strategy. This study tests whether animals with different sensory systems use different mechanisms to orient. The characin fish Astyanax fasciatus (Cuvier, 1819) exists in two morphs in the same species – a number of populations of blind cave fish that rely on their lateral line to gain fine-scale information from their surroundings, and eyed surface populations that can also use visual cues. Both forms of the species were trained to orient to a goal signalled by landmarks and by egocentrically based cues (turn left or right) in a T-maze. When these cues were placed in conflict by switching the landmark position, only the eyed fish used the landmarks to orient, reflecting a difference in the way that the two sensory systems of these animals operate. Our results have implications for the evolution of the mechanisms of orientation, suggesting that these mechanisms may be constrained by the sensory cues that are available and hence the type of information that animals are able to glean from their surroundings.     

Moving from Complaints to Action: Oppositional Consciousness and Collective Action in a Political Community

This article analyzes the process of youth political activism and development by drawing on ethnographic research on Asian and Pacific Islander youth activists. Young people revealed that collective action begins with a critical analysis of their lived experiences with inequalities. Their actions also involved oppositional consciousness that was nurtured in social justice-oriented community organizations. Tracking youth's successful efforts for school reform, I show how oppositional consciousness is realized and what activism looks like in practice.  [youth activism, oppositional consciousness, social–educational change, Asian and Pacific Islanders]     

Bacterial Cooperation Causes Systematic Errors in Pathogen Risk Assessment due to the Failure of the Independent Action Hypothesis

The Independent Action Hypothesis (IAH) states that pathogenic individuals (cells, spores, virus particles etc.) behave independently of each other, so that each has an independent probability of causing systemic infection or death. The IAH is not just of basic scientific interest; it forms the basis of our current estimates of infectious disease risk in humans. Despite the important role of the IAH in managing disease interventions for food and water-borne pathogens, experimental support for the IAH in bacterial pathogens is indirect at best. Moreover since the IAH was first proposed, cooperative behaviors have been discovered in a wide range of microorganisms, including many pathogens. A fundamental principle of cooperation is that the fitness of individuals is affected by the presence and behaviors of others, which is contrary to the assumption of independent action. In this paper, we test the IAH in Bacillus thuringiensis (B.t), a widely occurring insect pathogen that releases toxins that benefit others in the inoculum, infecting the diamondback moth, Plutella xylostella. By experimentally separating B.t. spores from their toxins, we demonstrate that the IAH fails because there is an interaction between toxin and spore effects on mortality, where the toxin effect is synergistic and cannot be accommodated by independence assumptions. Finally, we show that applying recommended IAH dose-response models to high dose data leads to systematic overestimation of mortality risks at low doses, due to the presence of synergistic pathogen interactions. Our results show that cooperative secretions can easily invalidate the IAH, and that such mechanistic details should be incorporated into pathogen risk analysis.     

Learning to Attend: Modeling the Shaping of Selectivity in Infero-temporal Cortex in a Categorization Task

Recent experiments on behaving monkeys have shown that learning a visual categorization task makes the neurons in infero-temporal cortex (ITC) more selective to the task-relevant features of the stimuli (Sigala and Logothetis in Nature 415 318–320, 2002). We hypothesize that such a selectivity modulation emerges from the interaction between ITC and other cortical area, presumably the prefrontal cortex (PFC), where the previously learned stimulus categories are encoded. We propose a biologically inspired model of excitatory and inhibitory spiking neurons with plastic synapses, modified according to a reward based Hebbian learning rule, to explain the experimental results and test the validity of our hypothesis. We assume that the ITC neurons, receiving feature selective inputs, form stronger connections with the category specific neurons to which they are consistently associated in rewarded trials. After learning, the top-down influence of PFC neurons enhances the selectivity of the ITC neurons encoding the behaviorally relevant features of the stimuli, as observed in the experiments. We conclude that the perceptual representation in visual areas like ITC can be strongly affected by the interaction with other areas which are devoted to higher cognitive functions. Electronic Supplementary Material: Supplementary material is available in the online: version of this article at http://dx.doi.org/10.007/s00422-006-0054-z     

The Failure in the Stabilization of Glioblastoma-Derived Cell Lines: Spontaneous In Vitro Senescence as the Main Culprit

Cell line analysis is an important element of cancer research. Despite the progress in glioblastoma cell culturing, the cells isolated from the majority of specimens cannot be propagated infinitely in vitro. The aim of this study was to identify the processes responsible for the stabilization failure. Therefore, we analyzed 56 primary GB cultures, 7 of which were stabilized. Our results indicate that senescence is primarily responsible for the glioblastoma cell line stabilization failure, while mitotic catastrophe and apoptosis play a minor role. Moreover, a new technical approach allowed for a more profound analysis of the senescent cells in primary cultures, including the distinction between tumor and normal cells. In addition, we observed that glioblastoma cells in primary cultures have a varied potential to undergo spontaneous in vitro senescence, which is often higher than that of the normal cells infiltrating the tumor. Thus, this is the first report of GB cells in primary cell cultures (including both monolayer and spheroid conditions) rapidly and spontaneously becoming senescent. Intriguingly, our data also suggest that nearly half of GB cell lines have a combination of TP53 mutation and CDKN2A homozygous deletion, which are considered as mutually exclusive in glioblastoma. Moreover, recognition of the mechanisms of senescence and mitotic catastrophe in glioblastoma cells may be a step towards a potential new therapeutic approach.     

A Place Containing Many Places: Museums and the Use of Objects to Represent Place in Melanesia

In this paper I discuss a number of incompatible ways of comprehending object meanings, contrasting western ethnographic museum practice with indigenous, specifically ni-Vanuatu, understandings. I discuss these differences as a way of looking analytically at some of the practices of museum ethnography and material culture studies. There are several aspects to this contrast: here I concentrate on ideas about place. Place is a centrally important concept in Vanuatu, but is not privileged in relation to objects. Western museums, however, use provenance as any ethnographic object's defining characteristic, and have developed a sophisticated, though largely unexamined, set of principles and practices for the attribution of provenance on stylistic grounds. On the basis of provenance identification, museums attribute meaning to objects. When enshrined as professional museum practice, such approaches pose dilemmas for Melanesian museums, and are the subject of debate among Pacific region museum professionals. For ni-Vanuatu, the significance of objects on display may represent not places, but the performance of the skills that reveal the maker's place-based identity.     

Task partitioning in a robot swarm: a study on the effect of communication

Task partitioning consists in dividing a task into sub-tasks that can be tackled separately. Partitioning a task might have both positive and negative effects: On the one hand, partitioning might reduce physical interference between workers, enhance exploitation of specialization, and increase efficiency. On the other hand, partitioning may introduce overheads due to coordination requirements. As a result, whether partitioning is advantageous or not has to be evaluated on a case-by-case basis. In this paper we consider the case in which a swarm of robots must decide whether to complete a given task as an unpartitioned task, or utilize task partitioning and tackle it as a sequence of two sub-tasks. We show that the problem of selecting between the two options can be formulated as a multi-armed bandit problem and tackled with algorithms that have been proposed in the reinforcement learning literature. Additionally, we study the implications of using explicit communication between the robots to tackle the studied task partitioning problem. We consider a foraging scenario as a testbed and we perform simulation-based experiments to evaluate the behavior of the system. The results confirm that existing multi-armed bandit algorithms can be employed in the context of task partitioning. The use of communication can result in better performance, but in may also hinder the flexibility of the system.     

Representation of differential expression: a new approach to study differential gene expression in trypanosomatids

During the past five years, several methods have been described that allow the isolation and cloning of stage-specific or cell-specific genes. The characterization of genes expressed at different stages of parasite development is of the utmost importance for the understanding of the mechanisms involved in the regulation of gene expression. Here, Samuel Goldenberg and Marco Aurelio Krieger describe a method for the amplification and cloning of Trypanosoma cruzi genes expressed specifically at different times of the metacyclogenesis process. This method, representation of differential expression (RDE), should be useful for the isolation and cloning of any trypanosomatid gene transcribing differentially expressed messenger RNA.     

Cultivated Grapevines Represent a Symptomless Reservoir for the Transmission of Hop Stunt Viroid to Hop Crops: 15 Years of Evolutionary Analysis

Hop stunt was a mysterious disorder that first emerged in the 1940s in commercial hops in Japan. To investigate the origin of this disorder, we infected hops with natural Hop stunt viroid (HpSVd) isolates derived from four host species (hop, grapevine, plum and citrus), which except for hop represent possible sources of the ancestral viroid. These plants were maintained for 15 years, then analyzed the HpSVd variants present. Here we show that the variant originally found in cultivated grapevines gave rise to various combinations of mutations at positions 25, 26, 54, 193, and 281. However, upon prolonged infection, these variants underwent convergent evolution resulting in a limited number of adapted mutants. Some of them showed nucleotide sequences identical to those currently responsible for hop stunt epidemics in commercial hops in Japan, China, and the United States. Therefore, these results indicate that we have successfully reproduced the original process by which a natural HpSVd variant naturally introduced into cultivated hops was able to mutate into the HpSVd variants that are currently present in commercial hops. Furthermore, and importantly, we have identified cultivated grapevines as a symptomless reservoir in which HSVd can evolve and be transmitted to hop crops to cause epidemics.     

Failure of luteolysis leads to prolonged gestation in a bitch: a case report

A healthy, 5-yr-old rough collie bitch exhibited prolonged gestation, characterized by intrauterine fetal death and plasma progesterone concentrations (PPC) above 6 nmol/L/d until Day 65 or 66 of cytologic diestrus, which then only dropped following treatment with dinoprost tromethamine. The bitch showed no signs of parturition prior to laparotomy and hysterotomy on Day 63, which revealed 5 corpora lutea (CL) on the left ovary and 1 on the right ovary; 5 full-term, dead conceptuses without obvious autolysis but with 4 of the 5 placentas detached; and a tightly closed cervix. All conceptuses were in the left uterine horn. Treatment with dinoprost tromethamine was initiated 1 d after hysterotomy and was continued for IO d (120 microg/kg twice daily for a total dose of 240 microg kg/d). The discharge of lochia through the cervix and lactation started 3 d after the onset of treatment. Plasma progesterone concentration was 14.4, 16.2 and 1.6 nmol/L/d on the day of hysterotomy and at 1 and 3 d after the onset of prostaglandin therapy, respectively. The reason for the failure of luteolysis to occur is not known.     

Failure to Demonstrate Systematic Changes in Olfactory Perception in the Course of Pregnancy: a Longitudinal Study

Olfactory function was assessed in 20 women during each trimesterof pregnancy and post partum, and compared with that of 20 non-pregnantwomen tested in parallel. In contrast to earlier reports, noconsistent differences in olfactory sensitivity or odor evaluationwere found between the two groups. Chem. Senses 21: 567–571,1996.