Monocular and Binocular Contributions to Oculomotor Plasticity

Most eye movements in the real-world redirect the foveae to objects at a new depth and thus require the co-ordination of monocular saccade amplitudes and binocular vergence eye movements. Additionally to maintain the accuracy of these oculomotor control processes across the lifespan, ongoing calibration is required to compensate for errors in foveal landing positions. Such oculomotor plasticity has generally been studied under conditions in which both eyes receive a common error signal, which cannot resolve the long-standing debate regarding whether both eyes are innervated by a common cortical signal or by a separate signal for each eye. Here we examine oculomotor plasticity when error signals are independently manipulated in each eye, which can occur naturally owing to aging changes in each eye’s orbit and extra-ocular muscles, or in oculomotor dysfunctions. We find that both rapid saccades and slow vergence eye movements are continuously recalibrated independently of one another and corrections can occur in opposite directions in each eye. Whereas existing models assume a single cortical representation of space employed for the control of both eyes, our findings provide evidence for independent monoculomotor and binoculomotor plasticities and dissociable spatial mapping for each eye

Long-term and seasonal changes in nutrients, phytoplankton biomass, and dissolved oxygen in deep bay, Hong Kong

Deep Bay is a semienclosed bay that receives sewage from Shenzhen, a fast-growing city in China. NH 4 is the main N component of the sewage (>50% of total N) in the inner bay, and a twofold increase in NH 4 and PO 4 concentrations is attributed to increased sewage loading over the 21-year period (1986-2006). During this time series, the maximum annual average NH 4 and PO 4 concentrations exceeded 500 and 39 μM, respectively. The inner bay (Stns DM1 and DM2) has a long residence time and very high nutrient loads and yet much lower phytoplankton biomass (chlorophyll (Chl) 2 mg L -1) than expected. Because it is shallow (̃2 m), phytoplankton growth is likely limited by light due to mixing and suspended sediments, as well as by ammonium toxicity, and biomass accumulation is reduced by grazing, which may reduce the occurrence of hypoxia. Since nutrients were not limiting in the inner bay, the significant long-term increase in Chl a (0. 52-0. 57 μg L -1 year -1) was attributed to climatic effects in which the significant increase in rainfall (11 mm year -1) decreased salinity, increased stratification, and improved water stability. The outer bay (DM3 to DM5) has a high flushing rate (0. 2 day -1), is deeper (3 to 5 m), and has summer stratification, yet there are few large algal blooms and hypoxic events since dilution by the Pearl River discharge in summer, and the invasion of coastal water in winter is likely greater than the phytoplankton growth rate. A significant long-term increase in NO 3 (0. 45-0. 94 μM year -1) occurred in the outer bay, but no increasing trend was observed for SiO 4 or PO 4, and these long-term trends in NO 3, PO 4, and SiO 4 in the outer bay agreed with those long-term trends in the Pearl River discharge. Dissolved inorganic nitrogen (DIN) has approximately doubled from 35-62 to 68-107 μM in the outer bay during the last two decades, and consequently DIN to PO 4 molar ratios have also increased over twofold since there was no change in PO 4. The rapid increase in salinity and DO and the decrease in nutrients and suspended solids from the inner to the outer bay suggest that the sewage effluent from the inner bay is rapidly diluted and appears to have a limited effect on the phytoplankton of the adjacent waters beyond Deep Bay. Therefore, physical processes play a key role in reducing the risk of algal blooms and hypoxic events in Deep Bay. © 2009 Coastal and Estuarine Research Federation.published_or_final_versionSpringer Open Choice, 01 Dec 201

Gaussian-process-based demand forecasting for predictive control of drinking water networks

Trabajo presentado a la 9th International Conference on Critical Information Infrastructures Security, celebrada en Limassol (Chipre) del 13 al 15 de octubre de 2014.This paper focuses on short-term water demand forecasting for predictive control of DrinkingWater Networks (DWN) by using Gaussian Process (GP). For the predictive control strategy, system state prediction in a nite horizon are generated by a DWN model and demands are regarded as system disturbances. The goal is to provide a demand estimation within a given condence interval. For the sake of obtaining a desired forecasting performance, the forecasting process is carried out in two parts: the expected part is forecasted by Double-Seasonal Holt-Winters (DSHW) method and the stochastic part is forecasted by GP method. The mean value of water demand is rstly estimated by DSHW while GP provides estimations within a condence interval. GP is applied with random inputs to propagate uncertainty at each step. Results of the application of the proposed approach to a real case study based on the Barcelona DWN have shown that the general goal has been successfully reached.This work is partially supported by the research projects SHERECS DPI-2011-26243 and ECOCIS DPI-2013-48243-C2-1-R, both of the Spanish Ministry of Education, by EFFINET grant FP7-ICT-2012-318556 of the European Commission and by AGAUR Doctorat Industrial 2013-DI-041. Ye Wang also thanks China Scholarship Council for providing postgraduate scholarship.Peer Reviewe

The "Artificial Mathematician" Objection: Exploring the (Im)possibility of Automating Mathematical Understanding

Reuben Hersh confided to us that, about forty years ago, the late Paul Cohen predicted to him that at some unspecified point in the future, mathematicians would be replaced by computers. Rather than focus on computers replacing mathematicians, however, our aim is to consider the (im)possibility of human mathematicians being joined by “artificial mathematicians” in the proving practice—not just as a method of inquiry but as a fellow inquirer

Survival of dental implants in patients with oral cancer treated by surgery and radiotherapy: a retrospective study

BACKGROUND: The aim of this retrospective study was to evaluate the survival of dental implants placed after ablative surgery, in patients affected by oral cancer treated with or without radiotherapy. METHODS: We collected data for 34 subjects (22 females, 12 males; mean age: 51 ± 19) with malignant oral tumors who had been treated with ablative surgery and received dental implant rehabilitation between 2007 and 2012. Postoperative radiation therapy (less than 50 Gy) was delivered before implant placement in 12 patients. A total of 144 titanium implants were placed, at a minimum interval of 12 months, in irradiated and non-irradiated residual bone. RESULTS: Implant loss was dependent on the position and location of the implants (P = 0.05-0.1). Moreover, implant survival was dependent on whether the patient had received radiotherapy. This result was highly statistically significant (P < 0.01). Whether the implant was loaded is another highly significant (P < 0.01) factor determinin

Structure of a Model Dye/Titania Interface: Geometry of Benzoate on Rutile-TiO2 (110)(1 x 1)

Scanned-energy mode photoelectron diffraction (PhD) and ab initio density functional theory calculations have been employed to investigate the adsorption geometry of benzoate ([C6H5COO]−) on rutile-TiO2(110)(1 × 1). PhD data indicate that the benzoate moiety binds to the surface through both of its oxygen atoms to two adjacent fivefold surface titanium atoms in an essentially upright geometry. Moreover, its phenyl (C6H5−) and carboxylate ([−COO]−) groups are determined to be coplanar, being aligned along the [001] azimuth. This experimental result is consistent with the benzoate geometry emerging from DFT calculations conducted for laterally rather well-separated adsorbates. At shorter interadsorbate distances, the theoretical modeling predicts a more tilted and twisted adsorption geometry, where the phenyl and carboxylate groups are no longer coplanar; i.e., interadsorbate interactions influence the configuration of adsorbed benzoate

A novel pathway producing dimethylsulphide in bacteria is widespread in soil environments

The volatile compound dimethylsulphide (DMS) is important in climate regulation, the sulphur cycle and signalling to higher organisms. Microbial catabolism of the marine osmolyte dimethylsulphoniopropionate (DMSP) is thought to be the major biological process generating DMS. Here we report the discovery and characterisation of the first gene for DMSP-independent DMS production in any bacterium. This gene, mddA, encodes a methyltransferase that methylates methanethiol (MeSH) and generates DMS. MddA functions in many taxonomically diverse bacteria including sediment-dwelling pseudomonads, nitrogen-fixing bradyrhizobia and cyanobacteria, and mycobacteria, including the pathogen Mycobacterium tuberculosis. The mddA gene is present in metagenomes from varied environments, being particularly abundant in soil environments, where it is predicted to occur in up to 76% of bacteria. This novel pathway may significantly contribute to global DMS emissions, especially in terrestrial environments, and could represent a shift from the notion that DMSP is the only significant precursor of DMS

Gene mobility promotes the spread of resistance in bacterial populations

Theory predicts that horizontal gene transfer (HGT) expands the selective conditions under which genes spread in bacterial populations. Whereas vertically inherited genes can only spread by positively selected clonal expansion, mobile genetic elements can drive fixation of genes by infectious HGT. We tested this using populations of Pseudomonas fluorescens and the conjugative mercury resistance (Hg R) plasmid pQBR57. HGT expanded the selective conditions allowing the spread of Hg R: Chromosomal Hg R only increased in frequency under positive selection, whereas plasmid-encoded Hg R reached fixation with or without positive selection. Tracking plasmid dynamics over time revealed that the mode of Hg R inheritance varied across mercury environments. Under mercury selection, the spread of Hg R was driven primarily by clonal expansion while in the absence of mercury Hg R dynamics were dominated by infectious transfer. Thus, HGT is most likely to drive the spread of resistance genes in environments where resistance is useless

Iron, silicate, and light co-limitation of three Southern Ocean diatom species

The effect of combined iron, silicate, and light co-limitation was investigated in the three diatom species Actinocyclus sp. Ehrenberg, Chaetoceros dichaeta Ehrenberg, and Chaetoceros debilis Cleve, isolated from the Southern Ocean (SO). Growth of all species was co-limited by iron and silicate, reflected in a significant increase in the number of cell divisions compared to the control. Lowest relative Si uptake and drastic frustule malformation was found under iron and silicate co-limitation in C. dichaeta, while Si limitation in general caused cell elongation in both Chaetoceros species. Higher light intensities similar to SO surface conditions showed a negative impact on growth of C. dichaeta and Actinocyclus sp. and no effect on C. debilis. This is in contrast to the assumed light limitation of SO diatoms due to deep wind driven mixing. Our results suggest that growth and species composition of Southern Ocean diatoms is influenced by a sensitive interaction of the abiotic factors, iron, silicate, and light

Effect of parasympathetic stimulation on brain activity during appraisal of fearful expressions

Autonomic nervous system activity is an important component of human emotion. Mental processes influence bodily physiology, which in turn feeds back to influence thoughts and feelings. Afferent cardiovascular signals from arterial baroreceptors in the carotid sinuses are processed within the brain and contribute to this two-way communication with the body. These carotid baroreceptors can be stimulated non-invasively by externally applying focal negative pressure bilaterally to the neck. In an experiment combining functional neuroimaging (fMRI) with carotid stimulation in healthy participants, we tested the hypothesis that manipulating afferent cardiovascular signals alters the central processing of emotional information (fearful and neutral facial expressions). Carotid stimulation, compared with sham stimulation, broadly attenuated activity across cortical and brainstem regions. Modulation of emotional processing was apparent as a significant expression-by-stimulation interaction within left amygdala, where responses during appraisal of fearful faces were selectively reduced by carotid stimulation. Moreover, activity reductions within insula, amygdala, and hippocampus correlated with the degree of stimulation-evoked change in the explicit emotional ratings of fearful faces. Across participants, individual differences in autonomic state (heart rate variability, a proxy measure of autonomic balance toward parasympathetic activity) predicted the extent to which carotid stimulation influenced neural (amygdala) responses during appraisal and subjective rating of fearful faces. Together our results provide mechanistic insight into the visceral component of emotion by identifying the neural substrates mediating cardiovascular influences on the processing of fear signals, potentially implicating central baroreflex mechanisms for anxiolytic treatment targets