Leptodactylus bufonius

Number of Pages: 22Integrative BiologyGeological Science

Brief Monocular Deprivation as an Assay of Short-Term Visual Sensory Plasticity in Schizophrenia - The Binocular Effect

Background: Visual sensory processing deficits are consistently observed in schizophrenia, with clear amplitude reduction of the visual evoked potential (VEP) during the initial 50-150 of processing. Similar deficits are seen in unaffected first-degree relatives and drug-naïve first-episode patients, pointing to these deficits as potential endophenotypic markers. Schizophrenia is also associated with deficits in neural plasticity, implicating dysfunction of both glutamatergic and GABAergic systems. Here, we sought to understand the intersection of these two domains, asking whether short-term plasticity during early visual processing is specifically affected in schizophrenia. Methods: Brief periods of monocular deprivation (MD) induce relatively rapid changes in the amplitude of the early VEP - i.e., short-term plasticity. Twenty patients and 20 non-psychiatric controls participated. VEPs were recorded during binocular viewing, and were compared to the sum of VEP responses during brief monocular viewing periods (i.e., Left-eye + Right-eye viewing). Results: Under monocular conditions, neurotypical controls exhibited an effect that patients failed to demonstrate. That is, the amplitude of the summed monocular VEPs was robustly greater than the amplitude elicited binocularly during the initial sensory processing period. In patients, this binocular effect was absent. Limitations: Patients were all medicated. Ideally, this study would also include first-episode unmedicated patients. Conclusion: These results suggest that short-term compensatory mechanisms that allow healthy individuals to generate robust VEPs in the context of MD are not effectively activated in patients with schizophrenia. This simple assay may provide a useful biomarker of short-term plasticity in the psychotic disorders and a target endophenotype for therapeutic interventions

“What” and “Where” in Auditory Sensory Processing: A High-Density Electrical Mapping Study of Distinct Neural Processes Underlying Sound Object Recognition and Sound Localization

Functionally distinct dorsal and ventral auditory pathways for sound localization (WHERE) and sound object recognition (WHAT) have been described in non-human primates. A handful of studies have explored differential processing within these streams in humans, with highly inconsistent findings. Stimuli employed have included simple tones, noise bursts, and speech sounds, with simulated left–right spatial manipulations, and in some cases participants were not required to actively discriminate the stimuli. Our contention is that these paradigms were not well suited to dissociating processing within the two streams. Our aim here was to determine how early in processing we could find evidence for dissociable pathways using better titrated WHAT and WHERE task conditions. The use of more compelling tasks should allow us to amplify differential processing within the dorsal and ventral pathways. We employed high-density electrical mapping using a relatively large and environmentally realistic stimulus set (seven animal calls) delivered from seven free-field spatial locations; with stimulus configuration identical across the “WHERE” and “WHAT” tasks. Topographic analysis revealed distinct dorsal and ventral auditory processing networks during the WHERE and WHAT tasks with the earliest point of divergence seen during the N1 component of the auditory evoked response, beginning at approximately 100 ms. While this difference occurred during the N1 timeframe, it was not a simple modulation of N1 amplitude as it displayed a wholly different topographic distribution to that of the N1. Global dissimilarity measures using topographic modulation analysis confirmed that this difference between tasks was driven by a shift in the underlying generator configuration. Minimum-norm source reconstruction revealed distinct activations that corresponded well with activity within putative dorsal and ventral auditory structures

Chemical impacts in fish and shellfish from Cape Cod and Massachusetts Bays

This paper is not subject to U.S. copyright. The definitive version was published in Environment Cape Cod 1, no. 3 (1998): 68-85.Mununichogs, soft shell clams, and blue mussels from some or all of 10 sites in Boston Harbor and Massachusetts and Cape Cod Bays were examined histologically: a suite of pathological changes previously known to be associated with chemical contamination were found in animals from the more contaminated sites. In particular, liver tumors were evident in 14% of the adult mununichogs from the Island End River, a tributary of the Mystic River in Boston Harbor. Additionally, a number of pathologies previously shown to be associated with chemical exposure were seen in the two bivalve species at a number of contaminated sites. Induction of cytochrome P45() IA (CYPIA) was also seen in muntntichogs from the more contaminated sites: CYPIA induction is a biochemical change associated with exposure to dioxin and other planar halogenated and aromatic hydrocarbons. These findings suggest that there are measurable biochemical and pathological changes in intertidal fish and shellfish from the more contaminated parts of the Massachusetts Bays system. These types of changes were less evident in the two reference sites in Cape Cod Bay

Hybrid-learning for social design

Underlying causes of conflict, inequity, and injustice remain deeply entrenched in the lives of people ranging from impoverished villages to overpopulated megalopolises. To help address these complex issues, social design brings together designers from varying disciplines to address the needs of the community. While universities across the world recognize the need to introduce social design pedagogy into their curriculum, many programs remain confined within Western post-graduate education. In response, two multidisciplinary professors initiated a team-taught \u27Design for Social Change\u27 course in an undergraduate design program in Dubai, UAE. Open to students across disciplines, the course followed a hybrid-learning approach to planning, conducting, and evaluating learning activities. The methodology empowered students to determine their project interest, cooperatively build research, and value their diverse skills. This paper introduces the notion of hybrid-learning, collabor-active team-teaching in an interdisciplinary classroom, and applies the methodology to a social design course in the MENA region. This paper has been presented as part of the Tasmeem Exploration Platform during Tasmeem Conference, Doha, 2013

Inelastic Diffraction and Spectroscopy of Very Weakly Bound Clusters

We study the coherent inelastic diffraction of very weakly bound two body clusters from a material transmission grating. We show that internal transitions of the clusters can lead to new separate peaks in the diffraction pattern whose angular positions determine the excitation energies. Using a quantum mechanical approach to few body scattering theory we determine the relative peak intensities for the diffraction of the van der Waals dimers (D_2)_2 and H_2-D_2. Based on the results for these realistic examples we discuss the possible applications and experimental challenges of this coherent inelastic diffraction technique.Comment: 15 pages + 5 figures. J. Phys. B (in press

A Very Low Resource Language Speech Corpus for Computational Language Documentation Experiments

Most speech and language technologies are trained with massive amounts of speech and text information. However, most of the world languages do not have such resources or stable orthography. Systems constructed under these almost zero resource conditions are not only promising for speech technology but also for computational language documentation. The goal of computational language documentation is to help field linguists to (semi-)automatically analyze and annotate audio recordings of endangered and unwritten languages. Example tasks are automatic phoneme discovery or lexicon discovery from the speech signal. This paper presents a speech corpus collected during a realistic language documentation process. It is made up of 5k speech utterances in Mboshi (Bantu C25) aligned to French text translations. Speech transcriptions are also made available: they correspond to a non-standard graphemic form close to the language phonology. We present how the data was collected, cleaned and processed and we illustrate its use through a zero-resource task: spoken term discovery. The dataset is made available to the community for reproducible computational language documentation experiments and their evaluation.Comment: accepted to LREC 201

Addition of H_2O and O_2 to Acetone and Dimethylsulfoxide Ligated Uranyl(V) Dioxocations

Gas-phase complexes of the formula [UO_2(lig)]^+ (lig = acetone (aco) or dimethylsulfoxide (dmso)) were generated by electrospray ionization (ESI) and studied by tandem ion-trap mass spectrometry to determine the general effect of ligand charge donation on the reactivity of UO_2^+ with respect to water and dioxygen. The original hypothesis that addition of O_2 is enhanced by strong σ-donor ligands bound to UO_2^+ is supported by results from competitive collision-induced dissociation (CID) experiments, which show near exclusive loss of H_2O from [UO_2(dmso)(H_2O)(O_2)]^+, whereas both H_2O and O_2 are eliminated from the corresponding [UO_2(aco)(H_2O)(O_2)]^+ species. Ligand-addition reaction rates were investigated by monitoring precursor and product ion intensities as a function of ion storage time in the ion-trap mass spectrometer: these experiments suggest that the association of dioxygen to the UO_2^+ complex is enhanced when the more basic dmso ligand was coordinated to the metal complex. Conversely, addition of H_2O is favored for the analogous complex ion that contains an aco ligand. Experimental rate measurements are supported by density function theory calculations of relative energies, which show stronger bonds between UO_2^+ and O_2 when dmso is the coordinating ligand, whereas bonds to H_2O are stronger for the aco complex

Two-Photon Spectroscopy Between States of Opposite Parities

Magnetic- and electric-dipole two-photon absorption (MED-TPA), recently introduced as a new spectroscopic technique for studying transitions between states of opposite parities, is investigated from a theoretical point of view. A new approximation, referred to as {\it weak quasi-closure approximation}, is used together with symmetry adaptation techniques to calculate the transition amplitude between states having well-defined symmetry properties. Selection rules for MED-TPA are derived and compared to selection rules for parity-forbidden electric-dipole two-photon absorption (ED-TPA).Comment: 7 pages, Revtex File, to be published in Physical Review

Variability of Luminous Stars in the Large Magellanic Cloud Using 10 Years of ASAS Data

Motivated by the detection of a recent outburst of the massive luminous blue variable LMC-R71, which reached an absolute magnitude M_V = -9.3 mag, we undertook a systematic study of the optical variability of 1268 massive stars in the Large Magellanic Cloud, using a recent catalog by Bonanos et al. (2009) as the input. The ASAS All Star Catalog (Pojmanski 2002) provided well-sampled light curves of these bright stars spanning 10 years. Combining the two catalogs resulted in 599 matches, on which we performed a variability search. We identified 117 variable stars, 38 of which were not known before, despite their brightness and large amplitude of variation. We found 13 periodic stars that we classify as eclipsing binary (EB) stars, eight of which are newly discovered bright, massive eclipsing binaries composed of OB type stars. The remaining 104 variables are either semi- or non-periodic, the majority (85) being red supergiants. Most (26) of the newly discovered variables in this category are also red supergiants with only three B and four O stars.Comment: 23 pages, 10 figures and 3 tables; published in A