80 research outputs found

    Sistema automatizado de riego y fertilización controlado por PLC LOGO 230RC para el cultivo de Maní en el Municipio de Managua, Comarca San Isidro Libertador, Comunidad Los Picones, Finca Santa Juana

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    Un sistema de fertilización e irrigación es la combinación de la automatización de procesos basada en un dispositivo Controlador Lógico Programable, con la agronomía, para solucionar problemas del productor, en el control de los recursos hídricos y de fertilización de cultivos. El sistema establece la unión de componentes físicos y lógicos que combinados proporcionan la posibilidad de irrigar y fertilizar los cultivos simultáneamente. Sus características se afectan por las necesidades del cultivo existente; y son las que condicionan el funcionamiento del sistema en todas las etapas. La programación se desarrolló en SIEMEN LOGO SOFT, en lenguaje diagrama de funciones, que permite programar de tal forma que las partes están interconectadas como un circuito eléctrico. El dispositivo controlará la activación de una electroválvula que accionará una bomba de riego que llevará el agua hasta la zona de acción y la activación de una segunda electroválvula que acciona el ingreso de un soluble fertilizante en el flujo de agua para riego. El costo del proyecto asciende a siete mil, seiscientos noventa y cuatro dólares con ochenta centavos (US$7,694.8) equivalente al tipo oficial de cambio dado por el Banco Central de 191,601.3 córdoba

    Spatial characterization of interictal high frequency oscillations in epileptic neocortex

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    Interictal high frequency oscillations (HFOs), in particular those with frequency components in excess of 200 Hz, have been proposed as important biomarkers of epileptic cortex as well as the genesis of seizures. We investigated the spatial extent, classification and distribution of HFOs using a dense 4 × 4 mm2 two dimensional microelectrode array implanted in the neocortex of four patients undergoing epilepsy surgery. The majority (97%) of oscillations detected included fast ripples and were concentrated in relatively few recording sites. While most HFOs were limited to single channels, ∼10% occurred on a larger spatial scale with simultaneous but morphologically distinct detections in multiple channels. Eighty per cent of these large-scale events were associated with interictal epileptiform discharges. We propose that large-scale HFOs, rather than the more frequent highly focal events, are the substrates of the HFOs detected by clinical depth electrodes. This feature was prominent in three patients but rarely seen in only one patient recorded outside epileptogenic cortex. Additionally, we found that HFOs were commonly associated with widespread interictal epileptiform discharges but not with locally generated ‘microdischarges’. Our observations raise the possibility that, rather than being initiators of epileptiform activity, fast ripples may be markers of a secondary local response

    Nuclear envelope protein Lem2 is required for mouse development and regulates MAP and AKT kinases

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    The nuclear lamina, along with associated nuclear membrane proteins, is a nexus for regulating signaling in the nucleus. Numerous human diseases arise from mutations in lamina proteins, and experimental models for these disorders have revealed aberrant regulation of various signaling pathways. Previously, we reported that the inner nuclear membrane protein Lem2, which is expressed at high levels in muscle, promotes the differentiation of cultured myoblasts by attenuating ERK signaling. Here, we have analyzed mice harboring a disrupted allele for the Lem2 gene (Lemd2). No gross phenotypic defects were seen in heterozygotes, although muscle regeneration induced by cardiotoxin was delayed. By contrast, homozygous Lemd2 knockout mice died by E11.5. Although many normal morphogenetic hallmarks were observed in E10.5 knockout embryos, most tissues were substantially reduced in size. This was accompanied by activation of multiple MAP kinases (ERK1/2, JNK, p38) and AKT. Knockdown of Lem2 expression in C2C12 myoblasts also led to activation of MAP kinases and AKT. These findings indicate that Lemd2 plays an essential role in mouse embryonic development and that it is involved in regulating several signaling pathways. Since increased MAP kinase and AKT/mTORC signaling is found in other animal models for diseases linked to nuclear lamina proteins, LEMD2 should be considered to be another candidate gene for human disease

    Time Multiplexed Active Neural Probe with 1356 Parallel Recording Sites

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    We present a high electrode density and high channel count CMOS (complementary metal-oxide-semiconductor) active neural probe containing 1344 neuron sized recording pixels (20 µm × 20 µm) and 12 reference pixels (20 µm × 80 µm), densely packed on a 50 µm thick, 100 µm wide, and 8 mm long shank. The active electrodes or pixels consist of dedicated in-situ circuits for signal source amplification, which are directly located under each electrode. The probe supports the simultaneous recording of all 1356 electrodes with sufficient signal to noise ratio for typical neuroscience applications. For enhanced performance, further noise reduction can be achieved while using half of the electrodes (678). Both of these numbers considerably surpass the state-of-the art active neural probes in both electrode count and number of recording channels. The measured input referred noise in the action potential band is 12.4 µVrms, while using 678 electrodes, with just 3 µW power dissipation per pixel and 45 µW per read-out channel (including data transmission)

    Emergence of polarized opinions from free association networks

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    We developed a method that can identify polarized public opinions by finding modules in a network of statistically related free word associations. Associations to the cue “migrant” were collected from two independent and comprehensive samples in Hungary (N1 = 505, N2 = 505). The co-occurrence-based relations of the free word associations reflected emotional similarity, and the modules of the association network were validated with well-established measures. The positive pole of the associations was gathered around the concept of “Refugees” who need help, whereas the negative pole associated asylum seekers with “Violence”. The results were relatively consistent in the two independent samples. We demonstrated that analyzing the modular organization of association networks can be a tool for identifying the most important dimensions of public opinion about a relevant social issue without using predefined constructs
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