The present paper describes fundamentals, advantages and limitations of the Box-Behnken design (BBD) for the optimization of analytical methods. It establishes also a comparison between this design ...and composite central, three-level full factorial and Doehlert designs. A detailed study on factors and responses involved during the optimization of analytical systems is also presented. Functions developed for calculation of multiple responses are discussed, including the desirability function
, which was proposed by Derringer and Suich in 1980. Concept and evaluation of robustness of analytical methods are also discussed. Finally, descriptions of applications of this technique for optimization of analytical methods are presented.
This paper proposes a neural network approach for forecasting short-term electricity prices. Almost until the end of last century, electricity supply was considered a public service and any price ...forecasting which was undertaken tended to be over the longer term, concerning future fuel prices and technical improvements. Nowadays, short-term forecasts have become increasingly important since the rise of the competitive electricity markets. In this new competitive framework, short-term price forecasting is required by producers and consumers to derive their bidding strategies to the electricity market. Accurate forecasting tools are essential for producers to maximize their profits, avowing profit losses over the misjudgement of future price movements, and for consumers to maximize their utilities. A three-layered feedforward neural network, trained by the Levenberg-Marquardt algorithm, is used for forecasting next-week electricity prices. We evaluate the accuracy of the price forecasting attained with the proposed neural network approach, reporting the results from the electricity markets of mainland Spain and California.
In light of recent alarming trends in human population growth, climate change, and other environmental modifications, a “Warning to humanity” manifesto was published in BioScience in 2017. This call ...reiterated most of the ideas originally expressed by the Union of Concerned Scientists in 1992, including the fear that we are “pushing Earth’s ecosystems beyond their capacities to support the web of life.” As subterranean biologists, we take this opportunity to emphasize the global importance and the conservation challenges associated with subterranean ecosystems. They likely represent the most widespread nonmarine environments on Earth, but specialized subterranean organisms remain among the least documented and studied. Largely overlooked in conservation policies, subterranean habitats play a critical role in the function of the web of life and provide important ecosystem services. We highlight the main threats to subterranean ecosystems and propose a set of effective actions to protect this globally important natural heritage.
Here, we investigate the transcriptome profiles of two S. Enteritidis and one S. Schwarzengrund isolates that present different persister levels when exposed to ciprofloxacin or ceftazidime. It was ...possible to note a distinct transcript profile among isolates, time of exposure, and treatment. We could not find a commonly expressed transcript profile that plays a role in persister formation after S. enterica exposure to beta-lactam or fluoroquinolone, as only three DEGs presented the same behavior under the conditions and isolates tested. It appears that the formation of persisters in S. enterica after exposure to ciprofloxacin is linked to the overexpression of genes involved in the SOS response (recA), cell division inhibitor (sulA), iron-sulfur metabolism (hscA and iscS), and type I TA system (tisB). On the other hand, most genes differentially expressed in S. enterica after exposure to ceftazidime appeared to be downregulated and were part of the flagellar assembly apparatus, citrate cycle (TCA cycle), glycolysis/gluconeogenesis, carbon metabolism, bacterial secretion system, quorum sensing, pyruvate metabolism pathway, and biosynthesis of secondary metabolites. The different transcriptome profiles found in S. enterica persisters induced by ciprofloxacin and ceftazidime suggest that these cells modulate their response differently according to each stress.
The Internet of Things (IoT) device scenario has several emerging technologies. Among them, Low-Power Wide-Area Networks (LPWANs) have proven to be efficient connections for smart devices. These ...devices communicate through gateways that exchange points with the central server. This study proposes an empirical and statistical methodology based on measurements carried out in a typical scenario of Amazonian cities composed of forests and buildings on the Campus of the Federal University of Pará (UFPA) to apply an adjustment to the coefficients in the UFPA propagation model. Furthermore, an Evolutionary Particle Swarm Optimization (EPSO) metaheuristic with multi-objective optimization was applied to maximize the coverage area and minimize the number of gateways to assist in the planning of a LoRa network. The results of simulations using the Monte Carlo method show that the EPSO-based gateway placement optimization methodology can be used to plan future LPWAN networks. As reception sensitivity is a decisive factor in the coverage area, with −108 dBm, the optimal solution determined the use of three gateways to cover the smart campus area.
Recovery of function after a stroke is determined by a balance of activity in the neural network involving both the affected and the unaffected brain hemispheres. Increased activity in the affected ...hemisphere can promote recovery, while excessive activity in the unaffected hemisphere may represent a maladaptive strategy. We therefore investigated whether reduction of the excitability in the unaffected hemisphere by cathodal transcranial direct current stimulation could result in motor performance improvement in stroke patients. We compared these results with excitability-enhancing anodal transcranial direct current stimulation of the affected hemisphere and sham transcranial direct current stimulation. Both cathodal stimulation of the unaffected hemisphere and anodal stimulation of the affected hemisphere (but not sham transcranial direct current stimulation) improved motor performance significantly. These results suggest that the appropriate modulation of bihemispheric brain structures can promote motor function recovery.
Abstract
Background
This exploratory study aimed to investigate the extent to which mechanical properties of the plantar skin and superficial soft tissue (hardness, stiffness, and thickness) and ...vibration perception thresholds (VPTs) predict plantar pressure loading during gait in people with diabetes compared to healthy controls.
Methods
Mechanical properties, VPTs, and plantar loadings during gait at the heel and first metatarsal head (MTH) of 20 subjects with diabetes, 13 with DPN, and 33 healthy controls were acquired. Multiple regression analyses were used to predict plantar pressure peaks and pressure-time integrals at both locations based on the mechanical properties of the skin and superficial soft tissues and VPTs.
Results
In the diabetes group at the MTH, skin hardness associated with 30-Hz (R
2
= 0.343) and 200-Hz (R
2
= 0.314) VPTs predicted peak pressure at the forefoot. In the controls at the heel, peak pressure was predicted by the skin thickness, hardness, and stiffness associated with 30-Hz (R
2
= 0.269, 0.268, and 0.267, respectively) and 200-Hz (R
2
= 0.214, 0.247, and 0.265, respectively) VPTs.
Conclusion
The forefoot loading of people with diabetes can be predicted by the hardness of the skin when combined with loss of vibration perception at low (30-Hz) and high (200-Hz) frequencies. Further data from larger sample sizes are needed to confirm the current findings.
Abstract The effect of environmental gradients on the remarkable diversity of mountain‐associated plants and on the species' abilities to cope with climate change transcends species‐specific ...strategies. For instance, our understanding of the impact of thermal gradients on ecological divergences in populations of widely distributed species is limited, although it could provide important insights regarding species' response to climate change. Here, we investigated whether populations of an endemic species broadly distributed across an elevation gradient employ unique or multiple divergent ecological strategies according to specific environmental conditions. We hypothesised that populations employ distinct strategies, producing a tolerance‐avoidance trade‐off related to the thermal conditions they experience across elevations. We conducted our research with 125 individuals of Pitcairnia flammea (Bromeliaceae) sampled from various elevations spanning from sea level to ~2200 m and cultivated under the same conditions. To assess specific ecological strategies of P. flammea populations across elevations, we examined leaf temperature, heat and cold tolerances, as well as other structural/morphological, optical, physiological and biochemical leaf traits. We majorly observed that water‐saving traits diminish as elevation increases while membrane fluidity, majorly associated with unsaturated and very‐long‐chain lipids, enhances. Low‐elevation individuals of P. flammea invest in water storage tissues, which likely prevent excessive water loss through the intense transpiration rates under warming periods. Conversely, high‐elevation plants exhibit increased membrane fluidity, a possible response to the stiffening induced by low temperature. Our results revealed a tolerance‐avoidance trade‐off related to thermal strategies of populations distributed across an elevation gradient. Low‐elevation plants avoid excessive leaf temperature by investing in water‐saving traits to maintain transpiration rates. High‐elevation individuals, in turn, tend to invest in membrane properties to tolerate thermal variations, particularly cold events. Our findings challenge the conventional notion that plants' vulnerability to warming depends on species‐specific thermal tolerance by showing diverse thermal strategies on populations across an elevation gradient. Read the free Plain Language Summary for this article on the Journal blog.
Resumo O efeito dos gradientes ambientais na grande diversidade de plantas associadas a montanhas transcende as estratégias específicas de cada espécie. Nosso entendimento sobre o impacto dos gradientes térmicos nas divergências ecológicas em populações de espécies amplamente distribuídas, por exemplo, é limitado, embora possa fornecer informações importantes sobre a resposta das espécies às mudanças climáticas. Aqui, investigamos se populações de uma espécie endêmica e amplamente distribuída em um gradiente altitudinal, empregam estratégias ecológicas únicas ou múltiplas de acordo com condições ambientais específicas. Nossa hipótese é que as populações empregam estratégias que resultam em um equilíbrio entre tolerância e evitação relacionado às condições térmicas que experimentam em diferentes altitudes. Analisamos 125 indivíduos de Pitcairnia flammea (Bromeliaceae) amostrados em diversas altitudes, desde o nível do mar até cerca de 2.200 metros, e cultivados nas mesmas condições. Para avaliar as estratégias ecológicas específicas das populações de P. flammea , examinamos temperatura foliar, tolerâncias ao calor e ao frio, além de outros traços foliares estruturais/morfológicos, óticos, fisiológicos e bioquímicos. Vimos que características de economia de água diminuem à medida que a altitude aumenta, enquanto a fluidez da membrana, associada principalmente a lipídios insaturados e de cadeia muito longa, aumenta. Indivíduos de baixa altitude investem em tecidos de armazenamento de água, provavelmente prevenindo a perda excessiva de água durante períodos de aquecimento e com taxas intensas de transpiração. Por outro lado, plantas de altas altitudes possuem maior fluidez de membrana, uma possível resposta ao enrijecimento induzido por baixas temperaturas. Nossos resultados revelaram um equilíbrio entre tolerância e evitação relacionado às estratégias térmicas de populações distribuídas ao longo de um gradiente de altitude. Plantas de baixa altitude evitam temperaturas foliares excessivas investindo em características de economia de água para manter as taxas de transpiração. Indivíduos de alta altitude, por sua vez, tendem a investir em membranas que toleram variações térmicas, especialmente eventos frios. Nossas descobertas desafiam a noção convencional de que a vulnerabilidade das plantas ao aquecimento depende da tolerância térmica específica da espécie, mostrando estratégias térmicas diversas em populações ao longo de um gradiente de altitude.
Capsule endoscopy (CE) is an important tool in the management of patients with known or suspected inflammatory bowel disease. Ulcers and erosions of the enteric mucosa are prevalent findings in these ...patients. They frequently occur together, and their identification in CE is crucial for an accurate evaluation of disease severity. Nevertheless, reviewing CE images is a time-consuming task, and the risk of overlooking lesions is significant.
Over the last decade, artificial intelligence (AI) has emerged as a means for overcoming these pitfalls. Of all AI methods, convolutional neural networks (CNN), due to their complex multilayer architecture present the best results in medical image analysis, particularly capsule endoscopy. Therefore, we aimed to develop a CNN for the automatic identification of ulcers and erosions in the small bowel mucosa. A total of 1483 CE exams (PillCam SB3®) performed at a single center between 2015 and 2020 were analysed. From these exams, a total of 6130 frames of the enteric mucosa were obtained, 4233 containing enteric ulcers and erosions, and the remaining containing normal mucosa or other findings. Ulcers and erosions were stratified according to Saurin’s classification for bleeding potential: P1E—erosions with intermediate bleeding risk; P1U—ulcers with intermediate bleeding risk; P2U—ulcers with high bleeding risk. For automatic identification of these lesions, these images were inserted into a CNN model with transfer learning. The pool of images was divided for constitution of training and validation datasets, comprising 80% and 20% of the total number of images, respectively. The output provided by the CNN was compared to the classification provided by a consensus of specialists. After optimizing the neural architecture of the algorithm, our model was able to automatically detect and distinguish ulcers and erosions (any bleeding potential) in the small intestine mucosa with an accuracy of 95.6%, sensitivity of 90.8%, and a specificity of 97.1%. We believe that our study lays the foundation for the development and application of effective AI tools to CE. These techniques should improve diagnostic accuracy and reading efficiency.
Graphic abstract
Schematic representation of the workflow and summary of the results.
We report a genome-wide association study to iron status. We identify an association of SNPs in TPMRSS6 to serum iron (rs855791, combined P = 1.5 × 10−20), transferrin saturation (combined P = 2.2 × ...10−23) and erythrocyte mean cell volume (MCV, combined P = 1.1 × 10−10). We also find suggestive evidence of association with blood hemoglobin levels (combined P = 5.3 × 10−7). These findings demonstrate the involvement of TMPRSS6 in control of iron homeostasis and in normal erythropoiesis.
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