462 research outputs found
North American Natural Gas Model Impact of Cross-Border Trade with Mexico
Natural gas as a source of energy has attracted a lot of interest as its emissions rate and price are lower than other fossil fuel energy sources. In the U.S., natural gas-fired power generation has been rising, as coal has declined as a share of the fuel mix. Likewise, Mexico recently launched its energy reform with focus on greatly expanding use of natural gas over other fossil fuels, primarily in the energy sector, by opening the market to private investors. These recent economic and policy changes, along with increasing gas production in the U.S. (shale gas boom) are likely to drive the natural gas market in North America in a new direction. For instance, the Annual Energy Outlook 2015 describes the U.S. for the first time as a net exporter of natural gas (via pipelines and LNG) by 2017. In order to study the current North American gas market with its new regulations like the Mexican energy reform, this paper presents the North American Natural Gas Market Model(NANGAM). We propose a long-term partial-equilibrium model of the United States, Mexican, and Canadian gas markets. NANGAM considers more granular details regarding market regions and pipelines in Mexico than other existing models, allows for endogenous infrastructure expansion, and is built in five year time-steps up to 2040, considering three seasons (low, high, and peak demand) for each time-step. NANGAM is calibrated using up-to-date data, which reflects current gas market trends, such as the increasing U.S. shale gas production. Using NANGAM, we assess the implications of the Mexican energy reform using a set of ad-hoc future scenarios. Results from the model show that, in the case of disappointing development of natural gas production in Mexico, the census region US7 (Texas and adjacent states) is the most affected, reaching an increase of natural gas production of up to 12% by 2040 compared to baseline projections
Analyzing the impact of demand response and reserves in islands energy planning
Small Islands usually rely on fossil fuels for their energy supply and face common challenges such as high energy costs and carbon dioxide emissions. For these reasons they represent interesting cases for analysing the transition towards a clean and secure energy system. Nevertheless, integrating non-dispatchable Renewable Energy Sources in the power grid causes stability issues and this is particularly true for island grids. Such issue is not fully considered in long-term energy planning; indeed, an important factor that should be considered in order to ensure the reliability of the grid are Reserves. There are different types of Reserves depending on the reactiveness/response time and the duration of the service. In this paper, primary and secondary reserves have been analysed in order to plan the long-term energy transition of the small island of Favignana, Italy by means of the new version of H2RES, a Linear Programming single-objective optimisation model able to provide a long-term capacity investment and dispatching optimisation. It has been found that biomass generators are favoured to both photovoltaic and wind turbines for their ability to provide reserves and also decrease the unpredictability of the supply. Batteries and Electrolysers are also used mostly for reserve provision
Remote ischemic preconditioning (RIPC) protects against endothelial dysfunction in a human model of systemic inflammation: a randomized clinical trial
Objective:
Inflammation, oxidative stress, and endothelial dysfunction are known to contribute to ischemia-reperfusion injury. Remote ischemic preconditioning (RIPC) protects from endothelial dysfunction and the damage induced by ischemia-reperfusion. Using intensive periodontal treatment (IPT), an established human model of acute systemic inflammation, we investigated whether RIPC prevents endothelial dysfunction and modulates systemic levels of inflammation and oxidative stress.
Approach and Results:
Forty-nine participants with periodontitis were randomly allocated to receive either 3 cycles of ischemia-reperfusion on the upper limb (N=24, RIPC) or a sham procedure (N=25, control) before IPT. Endothelial function assessed by flow-mediated dilatation of the brachial artery, inflammatory cytokines, markers of vascular injury, and oxidative stress were evaluated at baseline, day 1, and day 7 after IPT. Twenty-four hours post-IPT, the RIPC group had lower levels of IL-10 (interleukin-10) and IL-12 (interleukin-12) compared with the control group (P<0.05). RIPC attenuated the IPT-induced increase in IL-1β (interleukin-1β), E-selectin, sICAM-3 (soluble intercellular adhesion molecule 3), and sTM (soluble thrombomodulin) levels between the baseline and day 1 (P for interaction <0.1). Conversely, oxidative stress was differentially increased at day1 in the RIPC group compared with the control group (P for interaction <0.1). This was accompanied by a better flow-mediated dilatation (mean difference 1.75% [95% CI, 0.428–3.07], P=0.011). After 7 days from IPT, most of the inflammatory markers, endothelial-dependent and -independent vasodilation, were similar between groups.
Conclusions:
RIPC prevented acute endothelial dysfunction by modulation of inflammation and oxidation processes in patients with periodontitis following exposure to an acute inflammatory stimulus
Functional consequences of seven novel mutations in the CYP11B1 Gene: four mutations associated with nonclassic and three mutations causing classic 11 -Hydroxylase Deficiency
Context: Steroid 11β-hydroxylase (CYP11B1) deficiency (11OHD) is the second most common form of congenital adrenal hyperplasia (CAH). Cases of nonclassic 11OHD are rare compared with the incidence of nonclassic 21-hydroxylase deficiency.
Objective: The aim of the study was to analyze the functional consequences of seven novel CYP11B1 mutations (p.M88I, p.W116G, p.P159L, p.A165D, p.K254_A259del, p.R366C, p.T401A) found in three patients with classic 11OHD, two patients with nonclassic 11OHD, and three heterozygous carriers for CYP11B1 mutations.
Methods: We conducted functional studies employing a COS7 cell in vitro expression system comparing wild-type (WT) and mutant CYP11B1 activity. Mutants were examined in a computational three-dimensional model of the CYP11B1 protein.
Results: All mutations (p.W116G, p.A165D, p.K254_A259del) found in patients with classic 11OHD have absent or very little 11β-hydroxylase activity relative to WT. The mutations detected in patients with nonclassic 11OHD showed partial functional impairment, with one patient being homozygous (p.P159L; 25% of WT) and the other patient compound heterozygous for a novel mild p.M88I (40% of WT) and the known severe p.R383Q mutation. The two mutations detected in heterozygous carriers (p.R366C, p.T401A) also reduced CYP11B1 activity by 23 to 37%, respectively.
Conclusion: Functional analysis results allow for the classification of novel CYP11B1 mutations as causative for classic and nonclassic 11OHD, respectively. Four partially inactivating mutations are predicted to result in nonclassic 11OHD. These findings double the number of mild CYP11B1 mutations previously described as associated with mild 11OHD. Our data are important to predict phenotypic expression and provide important information for clinical and genetic counseling i
Eficacia del Ăndice de Moyers para predicciĂłn del tamaño mesiodistal de caninos y premolares en adolescentes Tumbes 2022
El objetivo fue determinar la eficacia del Ăndice del análisis Moyers para predicciĂłn
del tamaño mesiodistal de caninos y premolares, evaluó a adolescentes los cuales
cumplieron los criterios de selección de una institución educativa de 13 a 16 años
de edad. En este estudio se utilizaron las mediciones del ancho mesiodistal de los
cuatro incisivos inferiores, caninos y premolares, se obtuvieron las medidas
mediante modelos de estudio comparando al 75% de la tabla de predicciĂłn de
Moyers, para el maxilar superior e inferior y genero se obtuvo los valores
correspondientes. En los resultados no se obtuvo diferencia estadĂsticamente
significativa entre el promedio de la predicciĂłn de Moyers al 75% y el promedio
encontrado en la mediciĂłn de los modelos. El Ăndice de Moyers al 75% es eficaz
para ambos maxilares y no hay diferencia estadĂsticamente significativa de la
predicción del espacio y el género. Se concluye que el análisis de Moyers al 75%
utilizado es eficaz para la predicciĂłn del espacio requerido para caninos y
premolares en adolescentes de Tumbes 2022
Retinal nerve fiber layer thickness in children with primary congenital glaucoma measured by spectral domain optical coherence tomography
Purpose: To evaluate retinal nerve fiber layer (RNFL) thickness using spectral domain optical coherence tomography (SD-OCT) in a population of children diagnosed with primary congenital glaucoma (PCG).
Methods: In this cross-sectional study, 59 eyes of 59 children diagnosed with PCG and 87 eyes of 87 healthy children were evaluated by SD-OCT to measure the RNFL. The global average peripapillary RNFL thickness and sectional RNFL thickness were evaluated in both groups. Differences in global average and sectional thickness were analyzed.
Results: Mean age in the PCG group was 9.61 ± 3.23 years; in the control group, 8.47 ± 2.99 years (P = 0.0516). There were statistically significant differences (P < 0.007) in all sectors between both groups.
Conclusions: SD-OCT is a promising tool for evaluating the eyes of children diagnosed with PCG. Future research should examine the test–retest variability of SD-OCT parameters and their ability to diagnose progression in these children
Modeling Sustainability Reporting with Ternary Attractor Neural Networks
International Conference on Mining Intelligence and Knowledge Exploration. Cluj-Napoca, Romania, December 20–22, 2018This work models the Corporate Sustainability General Reporting
Initiative (GRI) using a ternary attractor network. A dataset of
years evolution of the GRI reports for a world-wide set of companies was
compiled from a recent work and adapted to match the pattern coding for
a ternary attractor network. We compare the performance of the network
with a classical binary attractor network. Two types of criteria were used
for encoding the ternary network, i.e., a simple and weighted threshold,
and the performance retrieval was better for the latter, highlighting the
importance of the real patterns’ transformation to the three-state coding.
The network exceeds the retrieval performance of the binary network for
the chosen correlated patterns (GRI). Finally, the ternary network was
proved to be robust to retrieve the GRI patterns with initial noise.This work has been supported by Spanish grants MINECO
(http://www.mineco.gob.es/) TIN2014-54580-R, TIN2017-84452-R, and by UAMSantander CEAL-AL/2017-08, and UDLA-SIS.MG.17.02
Influence of chronic ocular hypertension on emmetropia: Refractive, structural and functional study in two rat models
Chronic ocular hypertension (OHT) influences on refraction in youth and causes glaucoma in adulthood. However, the origin of the responsible mechanism is unclear. This study analyzes the effect of mild-moderate chronic OHT on refraction and neuroretina (structure and function) in young-adult Long-Evans rats using optical coherence tomography and electroretinography over 24 weeks. Data from 260 eyes were retrospectively analyzed in two cohorts: an ocular normotension (ONT) cohort (20 mmHg), in which OHT was induced either by sclerosing the episcleral veins (ES group) or by injecting microspheres into the anterior chamber. A trend toward emmetropia was found in both cohorts over time, though it was more pronounced in the OHT cohort (p < 0.001), especially in the ES group (p = 0.001) and males. IOP and refraction were negatively correlated at week 24 (p = 0.010). The OHT cohort showed early thickening in outer retinal sectors (p < 0.050) and the retinal nerve fiber layer, which later thinned. Electroretinography demonstrated early supranormal amplitudes and faster latencies that later declined. Chronic OHT accelerates emmetropia in Long–Evans rat eyes towards slowly progressive myopia, with an initial increase in structure and function that reversed over time. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
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