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result(s) for
"Gomez, Edgar"
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Application of data‐driven methods in power systems analysis and control
by
Chamorro, Harold R.
,
Gomez‐Diaz, Edgar O.
,
Ahmed, Shehab
in
Algorithms
,
Artificial intelligence
,
Control methods
2024
The increasing integration of variable renewable energy resources through power electronics has brought about substantial changes in the structure and dynamics of modern power systems. In response to these transformations, there has been a surge in the development of tools and algorithms leveraging real‐time computational power to enhance system operation and stability. Data‐driven methods have emerged as practical approaches for extracting reliable representations from non‐linear system data, enabling the identification of dynamics and system parameters essential for analysing stability and ensuring reliable operation. This study provides a comprehensive review of recent contributions in the literature concerning the application of data‐driven identification, analysis, and control methods in various aspects of power system operation. Specifically, the focus is on frequency support, power oscillation detection, and damping, which play crucial roles in maintaining grid stability. By discussing the challenges posed by parametric uncertainties, load and source variability, and reduced system inertia, this review sheds light on the opportunities for future research endeavours.
Journal Article
Polished diamond X‐ray lenses
by
Gomez, Edgar
,
Zinn, Thomas
,
Barrett, Raymond
in
Beryllium
,
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
,
compound refractive lenses
2022
High‐quality bi‐concave 2D focusing diamond X‐ray lenses of apex‐radius R = 100 µm produced via laser‐ablation and improved via mechanical polishing are presented here. Both for polished and unpolished individual lenses and for stacks of ten lenses, the remaining figure errors determined using X‐ray speckle tracking are shown and these results are compared with those of commercial R = 50 µm beryllium lenses that have similar focusing strength and physical aperture. For two stacks of ten diamond lenses (polished and unpolished) and a stack of eleven beryllium lenses, this paper presents measured 2D beam profiles out of focus and wire scans to obtain the beam size in the focal plane. These results are complemented with small‐angle X‐ray scattering (SAXS) measurements of a polished and an unpolished diamond lens. Again, this is compared with the SAXS of a beryllium lens. The polished X‐ray lenses show similar figure errors to commercially available beryllium lenses. While the beam size in the focal plane is comparable to that of the beryllium lenses, the SAXS signal of the polished diamond lenses is considerably lower. The performance of state‐of‐the‐art bi‐concave 2D focusing diamond X‐ray lenses produced via laser‐ablation and improved via a polishing process is reported.
Journal Article
Power system coherency recognition and islanding: Practical limits and future perspectives
by
Chamorro, Harold R.
,
Barocio, Emilio
,
Rueda, Jose L.
in
Control tasks
,
Damping
,
data analysis
2023
Electrical power systems are continuously upgrading into networks with a higher degree of automation capable of identifying and reacting to different events that may trigger undesirable situations. In power systems with decreasing inertia and damping levels, poorly damped oscillations with sustained or growing amplitudes following a disturbance may eventually lead to instability and provoke a major event such as a blackout. Additionally, with the increasing and considerable share of renewable power generation, unprecedented operational challenges shall be considered when proposing protection schemes against unstable electro‐mechanical (e.g. ringdown) oscillations. In an emergency situation, islanding operations enable splitting a power network into separate smaller networks to prevent a total blackout. Due to such changes, identifying the underlying types of oscillatory coherency and the islanding protocols are necessary for a continuously updating process to be incorporated into the existing power system monitoring and control tasks. This paper examines the existing evaluation methods and the islanding protocols as well as proposes an updated operational guideline based on the latest data‐analytic technologies.
Journal Article
The First Peopling of South America: New Evidence from Y-Chromosome Haplogroup Q
by
Battaglia, Vincenza
,
Woodward, Scott Ray
,
Angerhofer, Norman
in
Agriculture
,
Algorithms
,
Archaeology
2013
Recent progress in the phylogenetic resolution of the Y-chromosome phylogeny permits the male demographic dynamics and migratory events that occurred in Central and Southern America after the initial human spread into the Americas to be investigated at the regional level. To delve further into this issue, we examined more than 400 Native American Y chromosomes (collected in the region ranging from Mexico to South America) belonging to haplogroup Q - virtually the only branch of the Y phylogeny observed in modern-day Amerindians of Central and South America - together with 27 from Mongolia and Kamchatka. Two main founding lineages, Q1a3a1a-M3 and Q1a3a1-L54(xM3), were detected along with novel sub-clades of younger age and more restricted geographic distributions. The first was also observed in Far East Asia while no Q1a3a1-L54(xM3) Y chromosome was found in Asia except the southern Siberian-specific sub-clade Q1a3a1c-L330. Our data not only confirm a southern Siberian origin of ancestral populations that gave rise to Paleo-Indians and the differentiation of both Native American Q founding lineages in Beringia, but support their concomitant arrival in Mesoamerica, where Mexico acted as recipient for the first wave of migration, followed by a rapid southward migration, along the Pacific coast, into the Andean region. Although Q1a3a1a-M3 and Q1a3a1-L54(xM3) display overlapping general distributions, they show different patterns of evolution in the Mexican plateau and the Andean area, which can be explained by local differentiations due to demographic events triggered by the introduction of agriculture and associated with the flourishing of the Great Empires.
Journal Article
Characterization of the rat pituitary capsule: Evidence that the cerebrospinal fluid filled the pituitary cleft and the inner side of the capsule
by
Pérez-Torres, Armando
,
García-Godínez, Alejandro
,
González-del-Pliego, Margarita
in
Animals
,
Biology and Life Sciences
,
Blood vessels
2023
In humans, the pituitary gland is covered by a fibrous capsule and is considered a continuation of the meningeal sheath. However, in rodents some studies concluded that only the pars tuberalis (PT) and pars nervosa (PN) are enwrapped by the pia mater, while others showed that the whole gland is covered by this sheath. At PT the median eminence subarachnoid drains cerebrospinal fluid (CSF) to its cisternal system representing a pathway to the hypothalamus. In the present study we examined the rat pituitary capsule to elucidate its configuration, its physical interaction with the pituitary border and its relationship with the CSF. Furthermore, we also revisited the histology of the pituitary cleft and looked whether CSF drained in it. To answer such questions, we used scanning and transmission electron microscopy, intracerebroventricular infusion of Evan´s blue, fluorescent beads, and sodium fluorescein. The latter was measured in the pars distalis (PD) and various intracranial tissues. We found a pituitary capsule resembling leptomeninges, thick at the dorsal side of the pars intermedia (PI) and PD, thicker at the level of PI in contiguity with the PN and thinner at the rostro-ventral side as a thin membrane of fibroblast-like cells embedded in a fibrous layer. The capsule has abundant capillaries on all sides. Our results showed that the CSFs bathe between the capsule and the surface of the whole gland, and ciliate cells are present in the pituitary border. Our data suggest that the pituitary gland intercommunicates with the central nervous system (CNS) through the CSF.
Journal Article
“Wawa Pampay”: Andean Ritual for the Emotional Transformation of Grief in an Andean Community
by
Gutiérrez-Gómez, Edgar
,
Tristan-Quispe, Yanina Marleni
,
Andía-Ayme, Vidalina
in
Andes
,
Babies
,
Baptism
2025
The “Wawa Pampay” is an Andean funeral ritual that allows Quechua-speaking communities to collectively process grief over the death of a child, integrating ancestral beliefs and symbolic practices that have been passed down over generations. This study aimed to understand the cultural and emotional significance of this ritual, as well as to document its symbolic elements in light of the risk of its disappearance due to sociocultural changes. A qualitative approach integrating ethnographic methodology was used, combining participant observation, in-depth interviews in the Quechua language, and photographic and audiovisual recording, while always respecting the beliefs and privacy of the participants. The fieldwork was carried out in a rural community in the Peruvian Andes, with extended visits and cohabitation with the families. The findings show that the “Wawa Pampay” not only bids farewell to the deceased child but also reaffirms social cohesion and strengthens collective memory. Its preservation is key to keeping local cultural identity alive.
Journal Article
The Sacredness of Pampapu as a Religious Healing Ritual in the Andean Worldview
by
Gutiérrez-Gómez, Edgar
,
Auccatoma-Tinco, Roly
,
Quispe-Flores, Nilda
in
Ethnography
,
Interviews
,
offering
2026
This work focuses on the study of traditional Andean therapeutic knowledge of spirituality, understood as current practices that articulate health, territory, and sacredness. In a setting invaded by modernity and conventional medicine, Pampapu survives as a healing ritual that expresses a symbolic and spiritual relationship with the Earth and Andean deities. The objective is to understand the religious, cultural, and symbolic meanings that the inhabitants attribute to this ritual. It was carried out using qualitative research methods with an ethnographic and interpretive approach, based on participant observation and in-depth interviews with traditional healers, older adults, and patients’ families. Thematic and hermeneutic analysis confirmed categories such as sacredness, illness of the Earth, generational transmission, and religious syncretism. The results show that the ritual fulfills therapeutic functions, identity, and social cohesion, and is transmitted through generations. It is concluded that this practice constitutes a living expression of the Andean religious worldview and an essential component of intangible cultural heritage.
Journal Article
The Mitochondrial DNA Landscape of Modern Mexico
by
Perego, Ugo A.
,
Gomez, J. Edgar
,
Parson, Walther
in
American Indians or Alaska Natives - genetics
,
Blacks - genetics
,
Colonization
2021
Mexico is a rich source for anthropological and population genetic studies with high diversity in ethnic and linguistic groups. The country witnessed the rise and fall of major civilizations, including the Maya and Aztec, but resulting from European colonization, the population landscape has dramatically changed. Today, the majority of Mexicans do not identify themselves as Indigenous but as admixed, and appear to have very little in common with their pre-Columbian predecessors. However, when the maternally inherited mitochondrial (mt)DNA is investigated in the modern Mexican population, this is not the case. Control region sequences of 2021 samples deriving from all over the country revealed an overwhelming Indigenous American legacy, with almost 90% of mtDNAs belonging to the four major pan-American haplogroups A2, B2, C1, and D1. This finding supports a very low European contribution to the Mexican gene pool by female colonizers and confirms the effectiveness of employing uniparental markers as a tool to reconstruct a country’s history. In addition, the distinct frequency and dispersal patterns of Indigenous American and West Eurasian clades highlight the benefit such large and country-wide databases provide for studying the impact of colonialism from a female perspective and population stratification. The importance of geographical database subsets not only for forensic application is clearly demonstrated.
Journal Article
Nanoencapsulation of Phenolic Extracts from Native Potato Clones (Solanum tuberosum spp. andigena) by Spray Drying
by
Huamán-Carrión, Mary L.
,
Aguirre Landa, John Peter Aguirre
,
Moscoso-Moscoso, Elibet
in
Analysis
,
antioxidant capacity
,
Antioxidants
2023
Native potato clones grown in Peru contain bioactive compounds beneficial to human health. This study aimed to optimize the spray-drying nanoencapsulation of native potato phenolic extracts utilizing a central composite design and response surface methodology, obtaining the optimal treatment to an inlet temperature of 120 °C and an airflow of 141 L/h in the nano spray dryer B-90, which allowed maximizing the yield of encapsulation, antioxidant capacity (DPPH), encapsulation efficiency (EE), total phenolic compounds, and total flavonoids; on the other hand, it allowed minimizing hygroscopicity, water activity (Aw), and moisture. Instrumental characterization of the nanocapsules was also carried out, observing a gain in lightness, reddening of the color, and spherical nanoparticles of heterogeneous size (133.09–165.13 nm) with a negative ζ potential. Thermal, infrared, and morphological analyses confirmed the encapsulation of the core in the wall materials. Furthermore, an in vitro release study of phenolic compounds in an aqueous solution achieved a maximum value of 9.86 mg GAE/g after 12 h. Finally, the obtained nanocapsules could be used in the food and pharmaceutical industry.
Journal Article
Perceptions of City Managers About Open Government Policies: Concepts, Development, and Implementation in the Local Level of Government in Spain
by
Ruvalcaba-Gomez, Edgar Alejandro
,
Criado, J Ignacio
in
Access to information
,
Cities
,
City managers
2018
At this point, the role of the concept Open Government (OG) has been key promoting transparency, participation and collaboration in public administration worldwide. This article presents research about the open government (OG) phenomena in Spanish municipalities over 50,000 inhabitants (146 municipalities), using a questionnaire. Particularly, the research objective of this article is looking at the perceptions of city managers responsible for OG policies in order to understand more about this emergent public policy in the local layer of government. The results are consistent with a notion of OG associated to terms like transparency or access to information, and less to collaboration, co-production, of technologies or electronic government. In addition, the results confirm the intention of city managers to promote transparency or access to information with OG policies, while other possible outcomes (collaboration, managerial improvements or reduction of management costs) are less popular. Finally, the implementation of OG policies remains in its initial stages, whereas they are much expanded in strategic plans or units/departments at the local level of government in Spain.
Journal Article