A circadian clock regulates rod and cone input to fish retinal cone horizontal cells.

In the vertebrate retina, the light responses of post-receptor neurons depend on the ambient or background illumination. Using intracellular recording, we have found that a circadian clock regulates the light responses of dark-adapted fish cone horizontal cells. Goldfish were maintained on a 12-hr light/12-hr dark cycle. At different times of the day or night, retinas were superfused in darkness for 90 min ("prolonged darkness"), following which horizontal cells were impaled without the aid of any light flashes. In some of the experiments, fish were kept in constant darkness for 3-48 hr prior to surgery. After prolonged darkness during the night, but not during the day, the light responses of L-type cone horizontal cells resembled those of rod horizontal cells with respect to threshold, waveform, intensity-response functions, and spectral sensitivity. Following light sensitization during the night and day, the light responses of rod and cone horizontal cells were clearly different with respect to threshold, waveform, intensity-response functions, and spectral sensitivity. Under conditions of constant darkness for two full light/dark cycles, average responses of cone horizontal cells to a bright light stimulus during the subjective day were greater than during the subjective night. Prior reversal of the light/dark cycle reversed the 24-hr rhythm of cone horizontal cell responses to bright lights. In addition, following one full cycle of constant darkness, average cone horizontal cell spectral sensitivity during the subjective night closely matched that of rod horizontal cells, whereas average cone horizontal cell spectral sensitivity during the subjective day was similar to that of red (625 nm) cones. These results indicate that the effects of dark adaptation depend on the time of day and are regulated by a circadian clock so that cone input to cone horizontal cells predominates in the day and rod input predominates in the night.

Low-calcium-induced enhancement of chemical synaptic transmission from photoreceptors to horizontal cells in the vertebrate retina.

According to the classical calcium hypothesis of synaptic transmission, the release of neurotransmitter from presynaptic terminals occurs through an exocytotic process triggered by depolarization-induced presynaptic calcium influx. However, evidence has been accumulating in the last two decades indicating that, in many preparations, synaptic transmitter release can persist or even increase when calcium is omitted from the perfusing saline, leading to the notion of a "calcium-independent release" mechanism. Our study shows that the enhancement of synaptic transmission between photoreceptors and horizontal cells of the vertebrate retina induced by low-calcium media is caused by an increase of calcium influx into presynaptic terminals. This paradoxical effect is accounted for by modifications of surface potential on the photoreceptor membrane. Since lowering extracellular calcium concentration may likewise enhance calcium influx into other nerve cells, other experimental observations of "calcium-independent" release may be reaccommodated within the framework of the classical calcium hypothesis without invoking unconventional processes.

Feedback from luminosity horizontal cells mediates depolarizing responses of chromaticity horizontal cells in the Xenopus retina.

It has been proposed that the depolarizing responses of chromaticity horizontal cells (C-HCs) to red light depend on a feedback signal from luminosity horizontal cells (L-HCs) to short-wavelength-sensitive cones in the retinas of lower vertebrates. In this regard we studied the C-HCs of the Xenopus retina. C-HCs and L-HCs were identified by physiological criteria and then injected with neurobiotin. The retina then was incubated with peanut agglutinin, which stains red-but not blue-sensitive cones. Electron microscopic examination revealed that L-HCs contact all cone classes, whereas C-HCs contact only blue-sensitive cones. Simultaneous recordings from C-HC/L-HC pairs established that when the L-HC was saturated by a steady bright red light, C-HCs alone responded to a superimposed blue stimulus. In response to red test flashes, the C-HC response was delayed by approximately 30 msec with respect to the L-HC response. Isolated HCs of both subtypes were examined by whole-cell patch clamp. Both responded to kainate with sustained inward currents and to quisqualate or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) with desensitizing currents from a negative holding potential; i.e., both have AMPA-type glutamate receptors. gamma-Aminobutyric acid or glycine opened a chloride channel in the L-HC, whereas the C-HC was unresponsive to either inhibitory amino acid. Since glycine has been shown to abolish selectively the depolarizing response of the C-HC, this finding and other pharmacological data strongly implicate the L-HC in the underlying circuit. Moreover, because the C-HC does not respond to gamma-aminobutyric acid, the neurotransmitter of the L-HC, by elimination, a feedback synapse from L-HC to blue cone is the most plausible mechanism for the creation of depolarizing responses in C-HCs.

Tratamento de esgoto sanitário em reator anaeróbio horizontal de leito fixo (RAHLF): escala piloto

Este trabalho apresenta as avaliações de desempenho, das demandas operacionais e dos fatores intervenientes no aumento da escala da unidade piloto do Reator anaeróbio Horizontal de Leito Fixo (RAHLF) no tratamento de esgoto sanitário após passagem por peneira com malha de 1 mm, durante dois anos de operação. O reator dispunha de volume total de 237,5 1, construídos com tubos comerciais de PVC de 14,5 cm de diâmetro (D), dispostos em cinco módulos horizontais em série de 2,88 m, perfazendo um comprimento total de (L) de 14,4 m e relação de total de L/D de 100. O suporte de imobilização de biomassa, espuma de poliuretano em matrizes cúbicas de 1 cm de aresta, mostrou-se adequado ao desenvolvimento do biofilme. Em partida, sem inoculação prévia, ocorreu a sua consolidação a partir de 70 dias, com predominância de morfologia semelhante a Methanosaeta sp. em relação a da Methanosarcina. Em torno de 90 dias com afluente de 350 mg/l de DQO, observe-se a melhor qualidade do efluente, com valor de 100 mg/l de DQO. Em longa operação ocorreu queda de rendimento e menor reprodutibilidade das previsões do projeto, atribuída aos constantes entupimentos e ineficácia das operações de limpeza, com o comprometimento de volume reacional verificados por estudos de hidrodinâmica. Da investigação das origens dos equipamentos observou-se tratar mais de um efeito local e qualitativamente relacionado à biomassa retida que propriamente quantitativo e extensivo ao longo de todo reator, com produção continuada de polímeros extracelulares, promovendo um efeito sinérgico com os predominantes organismos filamentosos e com os sólidos particulados retidos no leito. Diante das potencialidades desta configuração de reator apontam-se alternativas de mitigação dos entupimentos e o direcionamento dos estudos necessários para novo aumento de escala para o tratamento de esgoto sanitário.

Horizontal Innovation and Interface Patents

Scholars understandably devote a great deal of effort to studying how well patent law works to incentive the most important inventions. After all, these inventions form the foundation of our new technological age. But very little time is spent focusing on the other end of the spectrum, inventions that are no better than what the public already has. At first blush, studying such “horizontal” innovation seems pointless. But this inquiry actually reveals much about how patents can be used in unintended, and arguably, anticompetitive ways. This issue has roots in one unintuitive aspect of patent law. Despite the law’s goal of promoting innovation, patents can be obtained on inventions that are no better than existing technology. Such patents might appear worthless, but companies regularly obtain these patents to cover interfaces. That is because interface patents actually derive value from two distinct characteristics. First, they can have “innovation value” that is based on how much better the patentedinterface is than existing technology. Second, interface patents can also have “compatibility value.” In other words, the patented technology is often essential to make products operate (i.e. compatible) with a particular interface. In practical terms, this means that an interface patent that covers little or no meaningful advance can give a company the ability to extract rents and foreclose competition. This undesirable result is a consequence of how patent law has structured its remedies. For years patent law has implicitly awarded both innovation and compatibility values. Recently, the courts have taken a sensible first step and excluded compatibility value from reasonable royalty recoveries for standard essential patents. This Article argues that the law needs to go further and do the same for all essential interface patents. Additionally, patent law should reform the way it awards injunctions and lost profits to also exclude compatibility value. This proposal has two benefits. It would eliminate the incentives for wasteful patents on horizontal technology. Second, and more importantly, the value of all interfacepatents would be better aligned with the goals of the patent system.

Horizontal and Vertical Interdependence in the Multinational Subsidiary Networks. ACES Working Paper No. 7, July 2008

Existing theoretical studies have predicted that a multinational firm's location choices are interdependent across countries. Little has, however, been done to test the hypothesis at individual subsidiary level. This paper uses a detailed French multinational subsidiary dataset and estimates how a firm's decision to invest in a foreign country is not only conditional on the characteristics of that country but also the firm's existing subsidiary network Using a structural spatial econometric model, the paper finds evidence of both horizontal and vertical interdependence in multinationals' location decisions. The results indicate that while multinational firms have little incentive to duplicate their production in countries with low bilateral trade costs, they are motivated to build a vertical subsidiary network in these countries ~ especially when the countries have complementary comparative advantages.

Adaptation of yeasts to fructose rich environments: a role for horizontal gene transfer of a fructose transporter

Abstract of the poster presented 33rd Small Meeting on Yeast Transport and Energetics, 21-24 July 2015, Lisbon, Portugal.

Beyond a logic of effectiveness: Horizontal coordination, democratic legitimacy and accountability

Horizontal coordination, where actors join together to accomplish a common task, has been applauded for its output legitimacy. However, such processes often face challenges due to opposition from local actors who raise concerns about democratic legitimacy and accountability. Moving beyond a logic of effectiveness, we aim to show how and why other forms of legitimacy such as input and throughput dimensions also affect horizontal coordination, in addition to output criteria. Beyond the assumed positive relationship between coordination and effectiveness, we additionally expect horizontal coordination to be (a) impeded by local actors' fear of losing democratic legitimacy; and (b) fostered by accountability in terms of the steering capacity of the state. A comparative case study analysis of water supply structures at the regional level in Switzerland shows, in contrast to our expectation, that effectiveness has mixed impacts on horizontal coordination. Rather than being solely a positive factor for horizontal coordination, certain output criteria such as financial redistribution are found to be a key hindrance. We also find that democratic legitimacy may, indeed, impede horizontal coordination whereas increased accountability positively affects such coordination.

Data compilation of ESOP

The work in this sub-project of ESOP focuses on the advective and convective transforma-tion of water masses in the Greenland Sea and its neighbouring areas. It includes observational work on the sub-mesoscale and analysis of hydrographic data up to the gyre-scale. Observations of active convective plumes were made with a towed chain equipped with up to 80 CTD sensors, giving a horizontal and vertical resolution of the hydrographic fields of a few metres. The observed scales of the penetrative convective plumes compare well with those given by theory. On the mesoscale the structure of homogeneous eddies formed as a result of deep convection was observed and the associated mixing and renewal of the intermediate layers quantified. The relative importance and efficiency of thermal and haline penetrative convection in relation to the surface boundary conditions (heat and salt fluxes and ice cover) and the ambient stratification are studied using the multi year time series of hydro-graphic data in the central Greenland Sea. The modification of the water column of the Greenland Sea gyre through advection from and mixing with water at its rim is assessed on longer time scales. The relative contributions are quantified using modern water mass analysis methods based on inverse techniques. Likewise the convective renewal and the spreading of the Arctic Intermediate Water from its formation area is quantified. The aim is to budget the heat and salt content of the water column, in particular of the low salinity surface layer, and to relate its seasonal and interannual variability to the lateral fluxes and the fluxes at the air-sea-ice interface. This will allow to estimate residence times for the different layers of the Greenland Sea gyre, a quantity important for the description of the Polar Ocean carbon cycle.