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"Méndez, F"
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QED-IR as topological quantum theory of dressed states
A
bstract
We investigate quantum electrodynamics in the infrared regime (QED-IR) using the adiabatic approximation and the framework of the functional Berry phase. In this approach, the physical state space is exact, nonperturbatively dressed, and endowed with a topological structure. Electrons do not exist as bare particles, but as topologically protected electron-photon clouds, defining a new kind of “infrared quantum”. These clouds are weakly bound in energy — with a binding scale estimated at Λ
IR
~ 0
.
5 meV — and remain stable provided photon energies remain below this threshold. Crucially, the theory becomes exactly solvable in this regime due to the quantization of the functional Berry flux, which governs the infrared dynamics of the dressed states.
When hard (high-energy) processes are involved, the topological protection of the dressed states is lifted, and the theory smoothly recovers conventional perturbative QED. In contrast, in the deep infrared, the electromagnetic interaction never fully vanishes, leading to observable effects. We argue that the energy required to dissolve the infrared electron-photon cloud in QED is of order meV, comparable to the thermal energy of the cosmic microwave background (CMB),
kT
CMB
≈ 2
.
3 10
−4
eV. However, the observed temperature anisotropies correspond to fluctuations near 10
−9
eV, far too small to destroy the cloud, though potentially capable of perturbing its topological phase structure. This suggests that CMB deviations could reflect residual topological imprints of the functional infrared dynamics. Finally, we propose that analogous cloud-like structures may manifest in other quantum systems governed by low-energy photon dynamics, such as atomic and molecular environments.
Journal Article
Effectiveness of a telerehabilitation intervention using ReCOVery APP of long COVID patients: a randomized, 3-month follow-up clinical trial
The main objective of this study is to analyze the clinical efficacy of telerehabilitation in the recovery of Long COVID patients through ReCOVery APP for 3 months, administered in the Primary Health Care context. The second objective is to identify significant models associated with an improvement in the study variables. An open-label randomized clinical trial was conducted using two parallel groups of a total of 100 Long COVID patients. The first group follows the treatment as usual methods established by their general practitioner (control group) and the second follows the same methods and also uses ReCOVery APP (intervention group). After the intervention, no significant differences were found in favour of the group intervention. Regarding adherence, 25% of the participants made significant use of the APP. Linear regression model establishes that the time of use of ReCOVery APP predicts an improvement in physical function (b = 0.001;
p
= 0.005) and community social support (b = 0.004;
p
= 0.021). In addition, an increase in self-efficacy and health literacy also contribute to improving cognitive function (b = 0.346;
p
= 0.001) and reducing the number of symptoms (b = 0.226;
p
= 0.002), respectively. In conclusion, the significant use of ReCOVery APP can contribute to the recovery of Long COVID patients.
Trial Registration No.: ISRCTN91104012.
Journal Article
The emotional well-being of Long COVID patients in relation to their symptoms, social support and stigmatization in social and health services: a qualitative study
Background
Long COVID patients have experienced a decline in their quality of life due to, in part but not wholly, its negative emotional impact. Some of the most prevalent mental health symptoms presented by long COVID patients are anxiety, depression, and sleep disorders. As such, the need has arisen to analyze the personal experiences of these patients to understand how they are managing their daily lives while dealing with the condition. The objective of this study is to increase understanding about the emotional well-being of people diagnosed with long COVID.
Methods
A qualitative design was created and carried out using 35 patients, with 17 participants being interviewed individually and 18 of them taking part in two focus groups. The participating patients were recruited in November and December 2021 from Primary Health Care (PHC) centers in the city of Zaragoza (Northern Spain) and from the Association of Long COVID Patients in Aragon. The study topics were emotional well-being, social support networks, and experience of discrimination. All an inductive thematic content analyses were performed iteratively using NVivo software.
Results
The Long COVID patients identified low levels of self-perceived well-being due to their persistent symptoms, as well as limitations in their daily lives that had been persistent for many months. Suicidal thoughts were also mentioned by several patients. They referred to anguish and anxiety about the future as well as a fear of reinfection or relapse and returning to work. Many of the participants reported that they have sought the help of a mental health professional. Most participants identified discriminatory situations in health care.
Conclusions
It is necessary to continue researching the impact that Long COVID has had on mental health, as well as to provide Primary Health Care professionals with evidence that can guide the emotional treatment of these patients
Journal Article
Biomedical Properties of Propolis on Diverse Chronic Diseases and Its Potential Applications and Health Benefits
The use of alternative medicine products has increased tremendously in recent decades and it is estimated that approximately 80% of patients globally depend on them for some part of their primary health care. Propolis is a beekeeping product widely used in alternative medicine. It is a natural resinous product that bees collect from various plants and mix with beeswax and salivary enzymes and comprises a complex mixture of compounds. Various biomedical properties of propolis have been studied and reported in infectious and non-infectious diseases. However, the pharmacological activity and chemical composition of propolis is highly variable depending on its geographical origin, so it is important to describe and study the biomedical properties of propolis from different geographic regions. A number of chronic diseases, such as diabetes, obesity, and cancer, are the leading causes of global mortality, generating significant economic losses in many countries. In this review, we focus on compiling relevant information about propolis research related to diabetes, obesity, and cancer. The study of propolis could generate both new and accessible alternatives for the treatment of various diseases and will help to effectively evaluate the safety of its use.
Journal Article
Modeling Biomass Production in Seasonal Wetlands Using MODIS NDVI Land Surface Phenology
Plant primary production is a key driver of several ecosystem functions in seasonal marshes, such as water purification and secondary production by wildlife and domestic animals. Knowledge of the spatio-temporal dynamics of biomass production is therefore essential for the management of resources—particularly in seasonal wetlands with variable flooding regimes. We propose a method to estimate standing aboveground plant biomass using NDVI Land Surface Phenology (LSP) derived from MODIS, which we calibrate and validate in the Doñana National Park’s marsh vegetation. Out of the different estimators tested, the Land Surface Phenology maximum NDVI (LSP-Maximum-NDVI) correlated best with ground-truth data of biomass production at five locations from 2001–2015 used to calibrate the models (R2 = 0.65). Estimators based on a single MODIS NDVI image performed worse (R2 ≤ 0.41). The LSP-Maximum-NDVI estimator was robust to environmental variation in precipitation and hydroperiod, and to spatial variation in the productivity and composition of the plant community. The determination of plant biomass using remote-sensing techniques, adequately supported by ground-truth data, may represent a key tool for the long-term monitoring and management of seasonal marsh ecosystems.
Journal Article
Explaining path-dependent rigidity traps: increasing returns, power, discourses, and entrepreneurship intertwined in social-ecological systems
The current, unprecedented rate of human development is causing major damages to Earth's life-support systems. Therefore, the need for transitions toward sustainability in the use of natural resources and ecosystems has been extensively advocated. To be successful, such transitions must be guided by a sound understanding of the architecture of the policy and institutional designs of both the process of change and the target outcome. Here, we contribute to current research on the institutional conditions necessary for successful transitions toward sustainability in social-ecological systems, addressing two interrelated theoretic-analytical questions through an in-depth case study focused in the Doñana region (Guadalquivir estuary, southwest Spain). First, we focus on the need for enhanced historical causal explanations of social-ecological systems stuck in maladaptive rigidity traps at present. Second, we focus on the explanatory potential of several factors for shaping maladaptive outcomes, at two different levels of analysis: political-economic interests, prevailing discourses and power, at a contextual level, and institutional entrepreneurship, at an endogenous level. In particular, we address that explanatory potential when the core logic of path dependence fails to predict maladaptive outcomes in a historical, evolutionary perspective. When this occurs, such outcomes are often qualified as unexpected, hence subject to contingency, because of their divergence from purported superior, optimal alternatives. We argue that contingency can be modulated away from randomness and better characterized as unpredictability, through the systematic inclusion of the mentioned factors into analysis. This would, in turn, increase our capacity to inform future policy and institutional transitional designs toward sustainability.
Journal Article
Clinical Presentation of Patients with Ebola Virus Disease in Conakry, Guinea
Ebola virus disease emerged in West Africa in March of 2014. In this report, the clinical presentation of 37 patients with confirmed EVD in Guinea is described during the early stages of the outbreak.
Ebola virus is one of three members of the Filoviridae family and comprises five distinct species. Infection with
Zaire ebolavirus
(EBOV) has historically resulted in the highest case fatality rate — up to 90%.
1
Outbreaks typically originate with introduction of the virus into humans from a wild animal reservoir, with subsequent human-to-human transmission, often fueled by nosocomial amplification in resource-poor settings. Aside from a single infection with
Tai Forest ebolavirus,
West Africa has never had an outbreak of Ebola virus disease (EVD).
2
,
3
The Republic of Guinea, on the west coast of Africa, has a population of approximately 11 million . . .
Journal Article
Long-term evaluation of surface air pollution in CAMSRA and MERRA-2 global reanalyses over Europe (2003–2020)
Over the last century, our societies have experienced a sharp increase in urban population and fossil-fuelled transportation, turning air pollution into a critical issue. It is therefore key to accurately characterize the spatiotemporal variability of surface air pollution in order to understand its effects upon the environment, knowledge that can then be used to design effective pollution reduction policies. Global atmospheric composition reanalyses offer great capabilities towards this characterization through assimilation of satellite measurements. However, they generally do not integrate surface measurements and thus remain affected by significant biases at ground level. In this study, we thoroughly evaluate two global atmospheric composition reanalyses, the Copernicus Atmosphere Monitoring Service (CAMSRA) and the Modern-Era Retrospective Analysis for Research and Applications v2 (MERRA-2), between 2003 and 2020, against independent surface measurements of O3, NO2, CO, SO2 and particulate matter (PM; both PM10 and PM2.5) over the European continent. Overall, both reanalyses present significant and persistent biases for almost all examined pollutants. CAMSRA clearly outperforms MERRA-2 in capturing the spatiotemporal variability of most pollutants, as shown by generally lower biases (all pollutants except for PM2.5), lower errors (all pollutants) and higher correlations (all pollutants except SO2). CAMSRA also outperforms MERRA-2 in capturing the annual trends found in all pollutants (except for SO2). Overall, CAMSRA tends to perform best for O3 and CO, followed by NO2 and PM10, while poorer results are typically found for SO2 and PM2.5. Higher correlations are generally found in autumn and/or winter for reactive gases. Compared to MERRA-2, CAMSRA assimilates a wider range of satellite products which, while enhancing the performance of the reanalysis in the troposphere (as shown by other studies), has a limited impact on the surface. The biases found in both reanalyses are likely explained by a combination of factors, including errors in emission inventories and/or sinks, a lack of surface data assimilation, and their relatively coarse resolution. Our results highlight the current limitations of reanalyses to represent surface pollution, which limits their applicability for health and environmental impact studies. When applied to reanalysis data, bias-correction methodologies based on surface observations should help to constrain the spatiotemporal variability of surface pollution and its associated impacts.
Journal Article
Transcript profiling of plastid ferrochelatase two mutants reveals that chloroplast singlet oxygen signals lead to global changes in RNA profiles and are mediated by Plant U-Box 4
Background
In response to environmental stresses, chloroplasts generate reactive oxygen species, including singlet oxygen (
1
O
2
), an excited state of oxygen that regulates chloroplast-to-nucleus (retrograde) signaling, chloroplast turnover, and programmed cell death (PCD). Yet, the central signaling mechanisms and downstream responses remain poorly understood. The
Arabidopsis thaliana plastid ferrochelatase two
(
fc2
) mutant conditionally accumulates
1
O
2
, and Plant U-Box 4 (PUB4), a cytoplasmic E3 ubiquitin ligase, is involved in propagating
1
O
2
signals for chloroplast turnover and cellular degradation. Thus, the
fc2
and
fc2 pub4
mutants are useful genetic tools to elucidate these signaling pathways. Previous studies have focused on the role of
1
O
2
in promoting cellular degradation in
fc2
mutants, but its impact on retrograde signaling from mature chloroplasts (the major site of
1
O
2
production) is poorly understood.
Results
To gain mechanistic insights into
1
O
2
signaling pathways, we compared transcriptomes of adult wt,
fc2
, and
fc2 pub4
plants. The accumulation of
1
O
2
in
fc2
plants broadly repressed genes involved in chloroplast function and photosynthesis, while inducing genes and transcription factors involved in abiotic and biotic stress, the biosynthesis of jasmonic acid (JA) and salicylic acid (SA), microautophagy, and senescence. Elevated JA and SA levels were observed in
1
O
2
-stressed
fc2
plants.
pub4
reversed most of this
1
O
2
-induced gene expression and reduced the JA content in
fc2
plants. The
pub4
mutation also blocked JA-induced senescence pathways in the dark. However
, fc2 pub4 plants
maintained constitutively elevated levels of SA even in the absence of bulk
1
O
2
accumulation.
Conclusions
Together, this work demonstrates that in
fc2
plants,
1
O
2
leads to a robust retrograde signal that may protect cells by downregulating photosynthesis and ROS production while simultaneously mounting a stress response involving SA and JA. The induction of microautophagy and senescence pathways indicate that
1
O
2
-induced cellular degradation is a genetic response to this stress, and the bulk of this transcriptional response is modulated by the PUB4 protein. However, the effect of
pub4
on hormone synthesis and signaling is complex and indicates that an intricate interplay of SA and JA are involved in promoting stress responses and programmed cell death during photo-oxidative damage.
Journal Article