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This article reports GaN super-heterojunction Schottky barrier diodes (SHJ-SBDs) with substantially improved performance. Metal-2DEG sidewall n-ohmic contacts were deployed to achieve low contact resistance of $0.75~\Omega ~ \cdot ~mm$ , avoiding the risk of abnormally high contact resistance caused by inaccurate etch depth control. A pGaN notch formed near the cathode successfully eliminated excessive hole conduction caused by the sidewall n-ohmic contact. Isolation was improved by a high-energy Al implantation step. The resulting SHJ-SBD exhibited a breakdown voltage (BV) of ~12.5 kV and a specific resistance of 100.8 $\text{m}\Omega ~ \cdot ~cm^{2}$ .

Presentamos dos teoremas importantes en la topología algebraica combinatoria y la geometría combinatoria convexa, estos son el teorema del nervio y el teorema de Helly, dando ejemplos de su uso y relevancia. Mostramos que extensores absolutos son equivalentes a retractos absolutos y que son propiedades topológicas lo cual permite, por ejemplo, obtener triangulaciones para espacios topológicos expresados en términos del nervio del complejo simplicial asociado. Así también la estructuras convexas abstractas tienen principal relevancia para espacios metrizables, en particular los conjuntos convexos son extensores absolutos y por tanto retractos, pudiendo así obtenerse cubrimientos regulares y buenos cubrimientos. El patrón de intersección de estos cubrimientos por convexos da lugar a tres números combinatorios importantes, el número de Helly, Radon y Caratheodory. Culminamos haciendo evidente algunas propiedades combinatorias que poseen estos números, en particular que entre los diversos usos del número de Helly.

One of the biggest challenges faced in Brazilian cities is proper solid waste management. The school can be an interlocutor in raising awareness by directing the teaching and learning process in order to change the individual and collective behavior of students. Thematic workshops are characterized as a pedagogical intervention in which environmental education is approached in a dynamic, interactive and creative way. The objective was to identify the perceptions that children from a municipal school in Cambé, PR, have about the solid waste theme, based on drawings made during a workshop called “Composting at school”. The workshop was conducted by 11 undergraduate students attending the Environmental Engineering course at the Federal Technological University of Paraná – accompanied by a professor coordinating the action. As teaching methods, dynamic exercises, games and conversations were used, all with the aim of integrating children and promoting a reflection on the role of each one in proper solid waste management. At the end of the activity, an evaluation questionnaire was proposed to the children, which contained the proposition of a drawing, so that they could portray what they learned and their perceptions about the solid waste theme. From a view guided by Content Analysis, the drawings were classified into three categories: a) workshop stages and dynamic exercises; b) techniques for solid waste management; and c) non-human life forms in solid waste management. The workshop was a promising environmental education strategy, as it was noted that the greater the interaction and the lighter and more pleasant the activity, the greater the learning.

Dysfunctional inflammatory pathways are associated with an increased risk of cancer, including colorectal cancer. We have previously identified and enriched for a self-renewing, colon cancer stem cell (CCSC) subpopulation in primary sporadic colorectal cancers (CRC) and a related subpopulation in ulcerative colitis (UC) patients defined by the stem cell marker, aldehyde dehydrogenase (ALDH). Subsequent work demonstrated that CCSC-initiated tumors are dependent on the inflammatory chemokine, CXCL8, a known inducer of tumor proliferation, angiogenesis and invasion. Here, we use RNA interference to target CXCL8 and its receptor, CXCR1, to establish the existence of a functional signaling pathway promoting tumor growth initiated by sporadic and colitis CCSCs. Knocking down either CXCL8 or CXCR1 had a dramatic effect on inhibiting both in vitro proliferation and angiogenesis. Likewise, tumorigenicity was significantly inhibited due to reduced levels of proliferation and angiogenesis. Decreased expression of cycle cell regulators cyclins D1 and B1 along with increased p21 levels suggested that the reduction in tumor growth is due to dysregulation of cell cycle progression. Therapeutically targeting the CXCL8-CXCR1 signaling pathway has the potential to block sustained tumorigenesis by inhibiting both CCSC- and pCCSC-induced proliferation and angiogenesis.

La microlitiasis testicular (MT) es una patología usualmente diagnosticada de forma incidental; en el país no existen reportes de esta entidad en adultos. La bibliografía informa mayor incidencia en individuos de raza negra, sin precisar la etiología; se asocia a subfertilidad e infertilidad. Es controversial su relación con neoplasias testiculares. Se presenta un caso clínico, se describe diferentes asociaciones clínicas y se plantea una posible conducta terapéutica ante esta enfermedad.

Germanium telluride (GeTe) is a phase change material (PCM) that has gained recent attention because of its incorporation as an active material for radio frequency (RF) switches, as well as memory and novel optoelectronic devices. Considering PCM-based RF switches, parasitic resistances from Ohmic contacts can be a limiting factor in device performance. Reduction of the contact resistance ( Rc) is therefore critical for reducing the on-state resistance to meet the requirements of high-frequency RF applications. To engineer the Schottky barrier between the metal contact and GeTe, Sn was tested as an interesting candidate to alter the composition of the semiconductor near its surface, potentially forming a narrow band gap (0.2 eV) SnTe or a graded alloy with SnTe in GeTe. For this purpose, a novel contact stack of Sn/Fe/Au was employed and compared to a conventional Ti/Pt/Au stack. Two different premetallization surface treatments of HCl and deionized (DI) H2O were employed to make a Te-rich and Ge-rich interface, respectively. Contact resistance values were extracted using the refined transfer length method. The best results were obtained with DI H2O for the Sn-based contacts but HCl treatment for the Ti/Pt/Au contacts. The as-deposited contacts had the Rc (ρc) of 0.006 Ω·mm (8 × 10-9 Ω·cm2) for Sn/Fe/Au and 0.010 Ω·mm (3 × 10-8 Ω·cm2) for Ti/Pt/Au. However, the Sn/Fe/Au contacts were thermally stable, and their resistance decreased further to 0.004 Ω·mm (4 × 10-9 Ω·cm2) after annealing at 200 °C. In contrast, the contact resistance of the Ti/Pt/Au stack increased to 0.012 Ω·mm (4 × 10-8 Ω·cm2). Transmission electron microscopy was used to characterize the interfacial reactions between the metals and GeTe. It was found that formation of SnTe at the interface, in addition to Fe diffusion (doping) into GeTe, is likely responsible for the superior performance of Sn/Fe/Au contacts, resulting in one of the lowest reported contact resistances on GeTe.

Molybdenum carbonitride films prepared by plasma enhanced atomic layer deposition were studied for use as Schottky contacts to n-type gallium nitride. Deposited using bis(tertbutylimino)bis(dimethylamino)molybdenum and a remote plasma N2/H2 plasma, the diodes capped with Ti/Au displayed excellent rectifying behavior with a barrier height of 0.87 ± 0.01 eV and an ideality factor of 1.02 ± 0.01 after annealing at 600 °C in N2. These characteristics surpass those of pure metal nitride Schottky diodes, possibly due to work function engineering due to the incorporation of C and use of a remote plasma to avoid process-induced defects. According to x-ray photoelectron spectroscopy and energy-dispersive x-ray spectroscopy, the film composition is approximately MoC0.3N0.7. Grazing incidence x-ray diffraction and plan-view transmission electron microscopy selected area electron diffraction are consistent with a rock salt structure with a lattice parameter of 0.42 nm.

In this chapter, we report on the findings of our group’s analysis of the Digital Forensic Research Workshop (DFRWS) IoT Forensic Challenge (2018–2019).

Although silicon (Si) currently dominates the semiconductor industry, its small 1.1 eV band gap limits its maximum operating temperature, which restricts its use in high-temperature, high-power devices. Gallium nitride (GaN) is an attractive semiconductor with its wide bandgap (3.4 eV), high electron mobility (1700 cm2/Vs), high electron saturation velocity (3 x 107 cm/s), large critical breakdown field (2 MV/cm), and thermal stability. The high-power capabilities of GaN allow for a reduction in device size, which can conserve physical space if used to replace conventional Si power devices. While the semiconductor itself can endure harsh operating conditions, the reliability of the metal/semiconductor contacts can be a limiting factor for its use. Schottky contacts should provide a high barrier height and low reverse leakage current, and they must be electrically stable over the lifetime of the device. In this study, three materials reported to have high work functions are compared as Schottky diodes to n-type GaN, each selected for its anticipated thermodynamic stability with GaN1 or the potential to minimize process-induced defects in the diodes or both. Rhenium (Re) diodes fabricated via electron beam deposition, molybdenum nitride (MoNx) diodes via remote plasma atomic layer deposition (ALD), and palladium (Pd) diodes via electroless deposition were investigated. Ti/Al-based ohmic contacts were employed. The Re/n-GaN Schottky diode was chosen for study because of its thermodynamic stability against metallurgical reactions1 and high work function (4.96 eV)2. The barrier heights were investigated by current–voltage (I-V) and capacitance–voltage (C-V) measurements at room temperature. Both techniques demonstrated that the barrier height increased after an anneal at 400°C for 5 min, yielding a barrier height of 0.88 eV and ideality factor of 1.02 from by I-V measurements, while the C-V measurements revealed a barrier height of 0.91 eV. These barrier heights and reverse leakage currents remained stable upon annealing in N2 at 600°C. The MoNx/n-GaN Schottky diode was chosen for study because of the reported high work function of MoNx (5.33 eV)3, its conductive and refractory nature, and its thermodynamic equilibrium with GaN4. Films were deposited with bis (tert-butylimido)-bis (dimethylamido) molybdenum and a 300 W remote N2/H2 plasma. Four-point probe measurements and x-ray photoelectron spectroscopy (XPS) were used to measure sheet resistance and composition. Barrier heights from the I-V measurements were 0.41 eV, and ideality factors were 1.4, with good stability upon annealing at 600°C. The Pd/n-GaN Schottky diode was chosen because of its high work function (5.12 eV)2 and its potential to be electrolessly deposited, offering a gentle technique to minimize process-induced defects in the GaN, although Pd is not expected to be in thermodynamic equilibrium with GaN. A new method for electroless deposition of Pd films onto GaN surfaces used palladium dichloride with sodium L-ascorbate as the reducing agent was developed. Profilometry, four-point probe measurements, energy dispersive x-ray spectroscopy, and XPS were used to measure film thickness, sheet resistance, resistivity, morphology, and composition. The process provided conductive and pure Pd films, but some challenges with nucleation of the film on GaN makes the process less robust. Barrier heights from the I-V measurements were 1.13–1.26 eV, and ideality factors were 1.02–1.05. However, Pd is not in thermodynamic equilibrium with GaN. Among the candidates tested so far, the Re diodes were overall the strongest candidate. Future work will involve stress testing followed by materials characterization to provide more information on stable metallizations for high-power GaN devices. The authors are grateful to Sandia National Laboratories (Andrew Allerman) for providing GaN epilayers. This work was funded by the Office of Naval Research under Grant N000141812360, distribution A, approved for public release, distribution is unlimited (DCN# 43-7434-20). S. E. Mohney and X. Lin, J. Electron. Mater, 25, 811–818 (1996). H. Michaelson, J. Appl. Phys. 48, 4729-4733, (1977): H. Matsuhashi and S. Nishikawa, Jpn. J. Appl. Phys., 33, 1293, (1994). H. S. Venugopalan and S. E. Mohney, Z Metallkd., 89, 184-186, (1998).

Hydrobromic acid (HBr) vapor was used to remove native oxide from an undoped (100) germanium (Ge) wafer with n-type conductivity and to passivate its surface against reoxidation. The Ge surfaces, examined by x-ray photoelectron spectroscopy, were suspended above a 48% HBr solution for 1, 10, 20, 60 min, and 24 h. A steady decrease in oxide thickness was observed for up to 60 min of HBr exposure time. Beyond this time, little or no difference was observed, and the wafers maintained subnanometer levels of oxidation. The stability of the passivated surface was then measured with each treated sample exposed to ambient air for 19 h. The samples exposed to HBr for 60 min or less reoxidized when exposed to air, while the sample previously exposed to HBr for 24 h showed levels of oxidation similar to the freshly passivated wafer, thereby demonstrating HBr vapor-phase treatment as a simple method for passivating Ge.

Perceptual adaptation, a fundamental property of all sensory systems, functions to attenuate neural and perceptual responses to sustained or redundant stimulation as a means of limiting neural saturation and of enhancing the detection of new transient stimuli. While our understanding of the complex physiological mechanisms underlying adaptation has grown in recent years, how these processes are affected by individual odorant properties remains unclear. Recent data from our laboratory demonstrate that the onset time course of perceptual odor adaptation can be estimated by use of a simultaneous-odorant-stimulus paradigm, where the delay from the onset of a relatively long-duration adapting odorant to the onset of a brief target odorant is varied. Adaptation was observed as an increase in threshold with increasing adapting-to-target-odorant onset delay. Using this technique, we compared the estimated onset time course for four common odorants (vanilla extract, coconut extract, vinegar and propanol). Thresholds were estimated for a brief target odorant presented during a simultaneous adapting odorant in a group of college-aged student volunteers (n = 124; 88 females). Onset of adaptation for the vanilla and coconut mixtures was more rapid than for vinegar and propanol, though the asymptotic levels (approximately 400 ms) of adaptation were similar for coconut extract, vanilla extract and vinegar. In contrast, propanol did not reach asymptotic levels within the 1,000-ms timeframe. Considering propanol is a pure alcohol, relative differences in trigeminal reactivity may partially explain this variance in adaptation contours. Practical Applications A method for capturing rapid changes in response to odor adaptation is described. The automated method can be reliably used to compare both the magnitude and time course for a wide range of stimuli. The technique may be reproduced to evaluate how individual olfactory sensitivity changes in response to prolonged stimulation. Importantly, this procedure can be used to assess shifts in odor perception on rapid timescales – in the 50–100-ms range, rather than seconds or minutes.

De diciembre 2009 a julio del 2010, se realizaron muestreos con el método de atarraya en la cuenca del río Reventazón, Costa Rica, con el propósito de analizar las especies presentes de pez diablo de la familia Loricariidae. Del trabajo de campo se capturaron 63 especímenes en la cuenca baja. La mayoría de los peces capturados fueron de la especie Hypostomus panamensis, seguidos por Pterygoplichthys sp. Por su parte, Hypostomus panamensis, se considera de origen panameño y con distribución en Costa Rica, en el Pacífico sur, por lo que se cree fue introducido en la cuenca del río Reventazón. Se considera oportuno implementar monitoreos de estas especies, para determinar su impacto en la fauna íctica autóctona.

// Sugong Chen 1, * , Robert C. Fisher 1, 2, * , Steven Signs 2 , L. Alex Molina 2 , Anitha K. Shenoy 3 , Maria-Cecilia Lopez 3 , Henry V. Baker 3 , John M. Koomen 4 , Yi Chen 4 , Haley Gittleman 5 , Jill Barnholtz-Sloan 5 , Annamarie Berg 2 , Henry D. Appelman 6 and Emina H. Huang 1, 2 1 Department of Surgery, University of Florida, Gainesville, Florida 32610, USA 2 Department of Stem Cell Biology and Regenerative Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio 44195, USA 3 Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32610, USA 4 Molecular Oncology and Proteomics, SRB3, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida 33612, USA 5 Bioinformatics, Case Comprehensive Cancer Center, Cleveland, Ohio 44106, USA 6 Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA * These authors have contributed equally to this work Correspondence to: Emina H. Huang, email: huange2@ccf.org Keywords: colon cancer stem cells, ALDEFLUOR, tumorigenesis, PI3K/Akt/mTOR signaling, apoptosis Received: February 05, 2016 Accepted: May 19, 2016 Published: June 8, 2016 ABSTRACT In sporadic colon cancer, colon cancer stem cells (CCSCs) initiate tumorigenesis and may contribute to late disease recurrences and metastases. We previously showed that aldehyde dehydrogenase (ALDH) activity (as indicated by the ALDEFLUOR ® assay) is an effective marker for highly enriching CCSCs for further evaluation. Here, we used comparative transcriptome and proteome approaches to identify signaling pathways overrepresented in the CCSC population. We found overexpression of several components of the phosphoinositide 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) signaling pathway, including PI3KR2, a regulatory subunit of PI3K. LY294002, a PI3K inhibitor, defined the contribution of the PI3K/Akt/mTOR signaling pathway in CCSCs. LY294002-treated CCSCs showed decreases in proliferation, sphere formation and self-renewal, in phosphorylation-dependent activation of Akt, and in expression of cyclin D1. Inhibition of PI3K in vivo reduced tumorigenicity, increased detection of cleaved caspase 3, an indicator of apoptosis, and elevated expression of the inflammatory chemokine, CXCL8. Collectively, these results indicate that PI3K/Akt/mTOR signaling controls CCSC proliferation and CCSC survival, and suggests that it would be useful to develop therapeutic agents that target this signaling pathway.

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2016. O presente trabalho reporta as reações de desfosforilação dos triésteres dietil 2,4-dinitrofenil fosfato (DEDNPP) e dimetil 4-nitrofenil fosfato (Paraoxon metílico) pela oxima 2-hidróxi-N-fenilacetamida (8), pralidoxima (2-PAM), diacetilmonoxima (DAM) e dimetilglioxima (DMG) em meio aquoso e meio micelar catiônico, utilizando-se o surfactante brometo de cetiltrimetilamônio (CTAB) como agente tensoativo. Um aumento de cerca de 10 milhões de vezes para a desfosforilação do DEDNPP e Paraoxon foi obtido na presença da oxima (8) em meio aquoso, em comparação com a reação dos triésteres somente em água, e seus principais produtos de reação foram identificados por meio de diferentes técnicas. Além disso, as micelas de CTAB facilitam o encontro dos reagentes e promovem um aumento significativo da velocidade de reação, devido principalmente ao seu caráter hidrofóbico em conjunto com o efeito eletrostático entre a interface catiônica micelar e o ânion oximato. As constantes de velocidade e de ligação entre os reagentes e a micela foram determinadas com êxito por meio do modelo da pseudofase e troca iônica, elucidando os conhecimentos dos efeitos hidrofóbicos e eletrostáticos no planejamento de nanoreatores para a efetiva decomposição de compostos organofosforados tóxicos na presença de alfa-nucleófilos, assim como na elaboração de novos antídotos contra a intoxicação por agentes neurotóxicos. Abstract: The present work reports the dephosphorylation reactions of the triesters diethyl 2,4-dinitrophenyl phosphate (DEDNPP) and dimethyl 4-nitrophenyl phosphate (methyl Paraoxon) by the oxime 2-hydroxyimino-N-phenylacetamide (8), pralidoxime (2-PAM), diacetylmonoxime (DAM), dimethylglyoxime (DMG) in aqueous and cationic micellar media, using cetyltrimethylammonium bromide (CTAB) as a surfactant. A rate enhancement of 10 million-fold in the dephosphorylation of DEDNPP and Paraoxon was obtained in the presence of the oxime (8) in aqueous medium, in comparison to the spontaneous hydrolysis of the triesters, and the key products of the reactions were identified by various techniques. Besides, the micelles of CTAB show to facilitate the encounter of the reactants and promote a significant rate enhancement of the reactions, due to their hydrophobic characters in addition to the electrostatic effect between the cationic surfactant and the anionic oximate. The reactions rate and binding constants of the reactants in the micelle were obtained using the pseudophase and ionic exchange model, enlightening the exploitation of hydrophobic and electrostatic effects in the planning of nanoreactors for the effective decomposition of organophosphates by alpha-nucleophiles, as well as into the development of more generally applicable antidotes for human poisoning by neurotoxic agents.

Made available in DSpace on 2022-04-28T19:01:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-01 A checklist of the fishes of the Tusubres River basin, Pacific coast of Costa Rica, compiled from field and museum surveys is herein presented. A total of 54 species, representing 47 genera and 27 families, were recorded. Peripheral species were dominant (64.8%), followed by secondary freshwater fishes (20.4%); primary freshwater fishes accounted only for 14.8% of the total fish diversity. Eleotridae (6 spp.), Gobiidae (6 spp.), Poeciliidae (5 spp.) and Characidae (4 spp.) were the most diverse. Two species (Caranx sexfasciatus, Carangidae; and Opisthonema libertate, Clupeidae) were new records for Costa Rican freshwaters, and two species (Gymnotus maculosus, Gymnotidae; and Lebiasina boruca, Lebiasinidae) was found to have expanded ranges. An identification key and a complete photographic album of all fish species recorded in the basin are presented. The results of this investigation provide a framework for future studies on biogeography, ecology and conservation on fishes from this area. Museo de Zoología, Universidad de Costa Rica Centro de Investigación en Ciencias del Mar y Limnologia (CIMAR), Universidad de Costa Rica Laboratório de Ictiologia, Departamento de Zoologia e Botânica, Universidade Estadual Paulista “Júlio de Mesquita Filho”, Rua Cristóvão Colombo, 2265 Centro de Servicio de Gestión Ambiental, NIC, Instituto Costarricense de Electricidad Department of Marine Biology and Environmental Sciences, University of Miyazaki, 1-1 Gakuen-Kibanadai- Nishi Kanagawa Prefectural Museum of Natural History, 499 Iryuda Laboratório de Ictiologia, Departamento de Zoologia e Botânica, Universidade Estadual Paulista “Júlio de Mesquita Filho”, Rua Cristóvão Colombo, 2265

En este artículo examinaremos algunas relaciones existentes entre los ideales principales y los conjuntos Apéry en un semigrupo numérico...

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-graduação em Química Na intenção de se construir modelos bio-inspirados baseados nas características de fosfoesterases, o presente trabalho relata o desenvolvimento de novos modelos teóricos com o intuito de explicar a eficiência catalítica de oximas e de íons Cu2+ nas reações de ésteres de fosfato, principalmente devido à sua importância em sistemas biológicos e também na degradação de compostos organofosforados tóxicos. Nesse sentido, as oximas mostraram ser nucleófilos muito eficientes na reação com o diéster bis(2,4-dinitrofenil) fosfato (BDNPP) quando realizada em meio micelar catiônico (CTABr). Essa reação foi descrita com êxito utilizando-se o modelo de pseudo-fase e troca iônica, e permitiu o ajuste eficiente dos dados experimentais. Tendo em vista a reação de hidrólise espontânea do BDNPP em pH 10, onde o tempo de reação pode chegar a 40 dias, observou-se que a reação é acelerada significativamente e ocorreu em apenas 9 minutos. Avaliou-se também a reação de hidrólise do triéster tris-2-piridil fosfato (2-TPP), na presença de diferentes íons metálicos divalentes, sendo que a reação realizada em meio micelar aniônico (SDS),promoveu um efeito catalítico de até 6400 vezes na presença de íons Cu2+, quando comparado com a reação feita em água. Salienta-se que a reação de hidrólise do tris-3-piridil fosfato (3-TPP) apresentou um efeito catalítico muito inferior ao observado para o isômero 2-TPP, em relação às reações realizadas em água pura. Este resultado indicou que a posição do átomo de nitrogênio no anel aromático possui um papel fundamental como centro de coordenação para os íons Cu2+ no estado de transição. In order to build bio-inspired models based on characteristics of phosphoesterases, the present work reports the development of some new theoretical models in order to explain the catalytic efficiency of oximes and metal ions in the hydrolysis reactions of phosphate esters, mainly due to its importance in biological systems and also in the degradation of toxic organophosphorus compounds. Thus, oximes proved to be very efficient nucleophiles in hydrolysis reaction with the diester bis (2,4-dinitrophenyl) phosphate (BDNPP) when realized in a cationic micellar medium (CTABr). This reaction was successfully described using the pseudo-phase ion exchange model, which allowed to fit the experimental data efficiently. Considering the spontaneous hydrolysis reaction of BDNPP at pH 10, where the reaction time can reach 40 days, the reaction was accelerated significantly and occurred in stunning 9 minutes. In addition, the hydrolysis reaction of the triester tris-2-pyridyl phosphate (2-TPP) was evaluated in the presence of different divalent metal ions, and when an anionic micellar medium (SDS) was used, a catalytic effect up to 6400 times in the presence of Cu2+ ions was observed when compared with the same reaction in water. The hydrolysis reaction of the tris-3-pyridyl phosphate (3-TPP) showed a much lower catalytic effect than that observed for the isomer 2-TPP, for the reactions in pure water. These results indicated that the position of the nitrogen atom in the aromatic ring had a key role as a coordinating center for the Cu2+ ions in the transition state.

Objectives - The overall objective of this proposal was to explore the effects of soil properties and management practices on C sequestration in soils and off-site losses of N.The specific objectives were: 1. to investigate and to quantify the effects of soil properties on C transformations that follow OW decomposition, C losses by gaseous emission, and its sequestration by organic and mineral components of the soil; 2. to investigate and to quantify the effects of soil properties on organic N mineralization and transformations in soil, its losses by leaching and gaseous emission; 3. to investigate and to quantify the effects of management practices and plants root activity and decomposition on C and N transformations; and 4. to upgrade the models NCSOIL and NCSWAP to include inorganic C and root exudation dynamics. The last objective has not been fulfilled due to difficulties in experimentally quantification of the effects of soil inorganic component on root exudation dynamics. Objective 4 was modified to explore the ability of NCSOIL to simulate organic matter decomposition and N transformations in non- and calcareous soils. Background - Rates of decomposition of organic plant residues or organic manures in soil determine the amount of carbon (C), which is mineralized and released as CO₂ versus the amount of C that is retained in soil organic matter (SOM). Decomposition rates also greatly influence the amount of nitrogen (N) which becomes available for plant uptake, is leached from the soil or lost as gaseous emission, versus that which is retained in SOM. Microbial decomposition of residues in soil is strongly influenced by soil management as well as soil chemical and physical properties and also by plant roots via the processes of mineral N uptake, respiration, exudation and decay.

ENELVEN, a regional electricity utility in Venezuela, has installed a total of five series capacitors in their grid to increase the capacity of existing overhead transmission lines serving the residential, petroleum and petrochemicals center of Maracaibo. A sixth series capacitor is planned for future extension of the grid in the same area. This paper focuses on the power system engineering efforts that were required in conjunction with the delivery of the five series capacitors banks. In order to assure that grid code criteria was met and that stresses on new and existing equipment was still acceptable, a number of engineering studies were performed. The following subtasks were given the utmost focus in this process: transient stability validation, insulation coordination and switching overvoltage studies, short circuit calculations, line circuit-breaker transient recovery voltage (TRV) determination, line protection coordination and sub synchronous resonance (SSR) studies. When series capacitors are to be introduced, the insulation co-ordination and the line breaker TRV stresses should be examined, as well as the impact the series capacitor will have on the line distance protections. The short circuit calculations are needed as the series capacitors will reduce grid impedances, but also for the rating of the series capacitors themselves. The issue of SSR was apparent in this case, as a thermal power plant was located one bus away from a series capacitor, with a prospective possibility for the grid to be configured in a way known to be prone to SSR. The above-listed engineering efforts are reviewed in the paper. Input conditions, study methodologies and end results are discussed. Overall the paper highlights how the challenges related to series capacitor implementation can be mastered, enabling a critical grid reinforcement to be realized under a fast-track schedule

Sea p un número primo. La construcción más familiar del anillo de los enteros p-ádicos ℤp, es como un límite proyectivo de cocientes de potencias del ideal (p) ◁ ℤ. Existe otra descripción de ℤp como un cociente del anillo de series de potencias ℤ[[X]], que aparece en algunos textos sobre análisis p-ádico (ver por ejemplo [3]). Más específicamente, existe un isomorfismo de anillos. Ψ : ℤ[[X]]/〈p − X〉 → ℤp. Sin embargo, este isomorfismo también es de carácter topológico, pero no existe una demostración de tal hecho en la literatura correspondiente. En este artículo probaremos, con suficiente detalle, que la descripción citada arriba también es válida en el contexto de los anillos topológicos.