Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 425
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Cell ; 187(14): 3652-3670.e40, 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38843833

RESUMEN

While ultraviolet (UV) radiation damages DNA, eliciting the DNA damage response (DDR), it also damages RNA, triggering transcriptome-wide ribosomal collisions and eliciting a ribotoxic stress response (RSR). However, the relative contributions, timing, and regulation of these pathways in determining cell fate is unclear. Here we use time-resolved phosphoproteomic, chemical-genetic, single-cell imaging, and biochemical approaches to create a chronological atlas of signaling events activated in cells responding to UV damage. We discover that UV-induced apoptosis is mediated by the RSR kinase ZAK and not through the DDR. We identify two negative-feedback modules that regulate ZAK-mediated apoptosis: (1) GCN2 activation limits ribosomal collisions and attenuates ZAK-mediated RSR and (2) ZAK activity leads to phosphodegron autophosphorylation and its subsequent degradation. These events tune ZAK's activity to collision levels to establish regimes of homeostasis, tolerance, and death, revealing its key role as the cellular sentinel for nucleic acid damage.


Asunto(s)
Apoptosis , Daño del ADN , Rayos Ultravioleta , Rayos Ultravioleta/efectos adversos , Apoptosis/efectos de la radiación , Fosforilación/efectos de la radiación , Humanos , Transducción de Señal/efectos de la radiación , Proteínas Serina-Treonina Quinasas/metabolismo , Estrés Fisiológico/efectos de la radiación , Ribosomas/metabolismo , Muerte Celular/efectos de la radiación
2.
Cell ; 182(2): 404-416.e14, 2020 07 23.
Artículo en Inglés | MEDLINE | ID: mdl-32610081

RESUMEN

Problems arising during translation of mRNAs lead to ribosome stalling and collisions that trigger a series of quality control events. However, the global cellular response to ribosome collisions has not been explored. Here, we uncover a function for ribosome collisions in signal transduction. Using translation elongation inhibitors and general cellular stress conditions, including amino acid starvation and UV irradiation, we show that ribosome collisions activate the stress-activated protein kinase (SAPK) and GCN2-mediated stress response pathways. We show that the MAPKKK ZAK functions as the sentinel for ribosome collisions and is required for immediate early activation of both SAPK (p38/JNK) and GCN2 signaling pathways. Selective ribosome profiling and biochemistry demonstrate that although ZAK generally associates with elongating ribosomes on polysomal mRNAs, it specifically auto-phosphorylates on the minimal unit of colliding ribosomes, the disome. Together, these results provide molecular insights into how perturbation of translational homeostasis regulates cell fate.


Asunto(s)
Ribosomas/metabolismo , Estrés Fisiológico , Transportadoras de Casetes de Unión a ATP/metabolismo , Anisomicina/farmacología , Apoptosis/efectos de los fármacos , Daño del ADN/efectos de la radiación , Activación Enzimática , Humanos , Quinasas Quinasa Quinasa PAM/deficiencia , Quinasas Quinasa Quinasa PAM/genética , Quinasas Quinasa Quinasa PAM/metabolismo , Proteína Quinasa 14 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 14 Activada por Mitógenos/metabolismo , Fosforilación , Polirribosomas/metabolismo , Isoformas de Proteínas/deficiencia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Interferencia de ARN , ARN Mensajero/metabolismo , ARN Interferente Pequeño/metabolismo , Transducción de Señal , Rayos Ultravioleta , eIF-2 Quinasa/metabolismo
3.
Mol Cell ; 84(9): 1711-1726.e11, 2024 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-38569554

RESUMEN

N6-methyladenosine (m6A) is a crucial RNA modification that regulates diverse biological processes in human cells, but its co-transcriptional deposition and functions remain poorly understood. Here, we identified the RNA helicase DDX21 with a previously unrecognized role in directing m6A modification on nascent RNA for co-transcriptional regulation. DDX21 interacts with METTL3 for co-recruitment to chromatin through its recognition of R-loops, which can be formed co-transcriptionally as nascent transcripts hybridize onto the template DNA strand. Moreover, DDX21's helicase activity is needed for METTL3-mediated m6A deposition onto nascent RNA following recruitment. At transcription termination regions, this nexus of actions promotes XRN2-mediated termination of RNAPII transcription. Disruption of any of these steps, including the loss of DDX21, METTL3, or their enzymatic activities, leads to defective termination that can induce DNA damage. Therefore, we propose that the R-loop-DDX21-METTL3 nexus forges the missing link for co-transcriptional modification of m6A, coordinating transcription termination and genome stability.


Asunto(s)
Adenosina , Adenosina/análogos & derivados , ARN Helicasas DEAD-box , Exorribonucleasas , Inestabilidad Genómica , Metiltransferasas , Estructuras R-Loop , ARN Polimerasa II , Terminación de la Transcripción Genética , Humanos , ARN Helicasas DEAD-box/metabolismo , ARN Helicasas DEAD-box/genética , Metiltransferasas/metabolismo , Metiltransferasas/genética , Adenosina/metabolismo , Adenosina/genética , Exorribonucleasas/metabolismo , Exorribonucleasas/genética , ARN Polimerasa II/metabolismo , ARN Polimerasa II/genética , Células HEK293 , Cromatina/metabolismo , Cromatina/genética , Daño del ADN , Células HeLa , ARN/metabolismo , ARN/genética , Transcripción Genética , Metilación de ARN
4.
EMBO J ; 43(4): 484-506, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38177497

RESUMEN

Stalled ribosomes are rescued by pathways that recycle the ribosome and target the nascent polypeptide for degradation. In E. coli, these pathways are triggered by ribosome collisions through the recruitment of SmrB, a nuclease that cleaves the mRNA. In B. subtilis, the related protein MutS2 was recently implicated in ribosome rescue. Here we show that MutS2 is recruited to collisions by its SMR and KOW domains, and we reveal the interaction of these domains with collided ribosomes by cryo-EM. Using a combination of in vivo and in vitro approaches, we show that MutS2 uses its ABC ATPase activity to split ribosomes, targeting the nascent peptide for degradation through the ribosome quality control pathway. However, unlike SmrB, which cleaves mRNA in E. coli, we see no evidence that MutS2 mediates mRNA cleavage or promotes ribosome rescue by tmRNA. These findings clarify the biochemical and cellular roles of MutS2 in ribosome rescue in B. subtilis and raise questions about how these pathways function differently in diverse bacteria.


Asunto(s)
Bacillus subtilis , Biosíntesis de Proteínas , ARN Mensajero/metabolismo , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Ribosomas/metabolismo , Péptidos/metabolismo
5.
Trends Biochem Sci ; 47(1): 82-97, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34607755

RESUMEN

The recent discovery that collision of ribosomes triggers quality control and stress responses in eukaryotes has shifted the perspective of the field. Collided eukaryotic ribosomes adopt a unique structure, acting as a ubiquitin signaling platform for various response factors. While several of the signals that determine which downstream pathways are activated have been uncovered, we are only beginning to learn how the specificity for the activation of each process is achieved during collisions. This review will summarize those findings and how ribosome-associated factors act as molecular sentinels, linking aberrations in translation to the overall cellular state. Insights into how cells respond to ribosome collision events will provide greater understanding of the role of the ribosome in the maintenance of cellular homeostasis.


Asunto(s)
Biosíntesis de Proteínas , ARN Mensajero/metabolismo , Ribosomas/metabolismo
6.
RNA ; 2024 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-39293933

RESUMEN

Translation elongation inhibitors are commonly used to study different cellular processes. Yet, their specific impact on transcription and mRNA decay has not been thoroughly assessed. Here we use TimeLapse sequencing to investigate how translational stress impacts mRNA dynamics in human cells. Our results reveal that a distinct group of transcripts is stabilized in response to the translation elongation inhibitor emetine. These stabilized mRNAs are short-lived at steady state and many of them encode C2H2 zinc finger proteins. The codon usage of these stabilized transcripts is suboptimal compared to other expressed transcripts, including other short-lived mRNAs that are not stabilized after emetine treatment. Finally, we show that stabilization of these transcripts is independent of ribosome quality control factors and signaling pathways activated by ribosome collisions. Our data describe a group of short-lived transcripts whose degradation is particularly sensitive to the inhibition of translation elongation.

7.
Trends Biochem Sci ; 46(9): 731-743, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33966939

RESUMEN

Ribosomes that stall inappropriately during protein synthesis harbor proteotoxic components linked to cellular stress and neurodegenerative diseases. Molecular mechanisms that rescue stalled ribosomes must selectively detect rare aberrant translational complexes and process the heterogeneous components. Ribosome-associated quality control pathways eliminate problematic messenger RNAs and nascent proteins on stalled translational complexes. In addition, recent studies have uncovered general principles of stall recognition upstream of quality control pathways and fail-safe mechanisms that ensure nascent proteome integrity. Here, we discuss developments in our mechanistic understanding of the detection and rescue of stalled ribosomal complexes in eukaryotes.


Asunto(s)
Biosíntesis de Proteínas , Ribosomas , Procesamiento Proteico-Postraduccional , Proteínas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ribosomas/metabolismo
8.
Conserv Biol ; 38(4): e14255, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38488338

RESUMEN

Bird collisions with buildings are responsible for a large number of bird deaths in cities around the world, yet they remain poorly studied outside North America. We conducted one of the first citywide fine-scale and landscape-scale analyses of bird-building collisions in Asia and used maximum entropy modeling (as commonly applied to species distribution modeling) in a novel way to assess the drivers of bird-building collisions in the tropical city-state of Singapore. We combined 7 years of community science observations with publicly available building and remote sensing data. Drivers of bird-building collisions varied among taxa. Some migratory taxa had a higher relative collision risk that was linked to areas with high building densities and high levels of nocturnal blue light pollution. Nonmigratory taxa had a higher collision risk in areas near forest cover. Projecting our results onto official long-term land-use plans, we predicted that future increases in bird-building collision risk stemmed from increases in blue light pollution and encroachment of buildings into forested areas and identified 6 potential collision hotspots linked to future developments. Our results suggest that bird-building collision mitigation measures need to account for the different drivers of collision for resident and migratory species and show that combining community science and ecological modeling can be a powerful approach for analyzing bird-building collision data.


Modelos de nicho ecológico para esclarecer los causantes bióticos y abióticos de las colisiones entre aves y edificios en una ciudad tropical asiática Resumen Las colisiones entre aves y edificios son causa de un gran número de muertes en todas las ciudades del mundo, y aun así se estudian muy poco fuera de América del Norte. Realizamos uno de los primeros análisis a escala fina y a escala de paisaje en una ciudad asiática y usamos el modelo de entropía máxima (como se aplica con frecuencia a los modelos de distribución de especies) de manera novedosa para analizar los causantes de estas colisiones en Singapur, una ciudad­estado tropical. Combinamos siete años de observaciones de ciencia comunitaria con los datos públicos de teledetección y construcción. Los causantes de las colisiones entre aves y edificios variaron entre taxones. Algunos taxones migratorios tuvieron un riesgo de colisión relativamente más alto relacionado con áreas de alta densidad de edificios y niveles elevados de contaminación lumínica de luz azul nocturna. Los taxones no migratorios tuvieron un riesgo de colisión más elevado en las áreas cercanas a la cobertura forestal. Con la proyección de nuestros resultados sobre los planes oficiales de uso de suelo a largo plazo, pronosticamos que el incremento en el futuro de colisiones entre aves y edificios vendrá del incremento en la contaminación de luz azul y la invasión de edificios en las áreas forestales; también identificamos seis potenciales puntos calientes de colisión relacionados a futuros desarrollos inmobiliarios. Nuestros resultados sugieren que para mitigar estas colisiones se necesita considerar los diferentes causantes de dichas colisiones para las especies migratorias y residentes y también muestran que la combinación de la ciencia comunitaria y los modelos ecológicos puede ser una estrategia poderosa para analizar los datos de colisiones entre aves y edificios.


Asunto(s)
Aves , Ciudades , Animales , Aves/fisiología , Singapur , Conservación de los Recursos Naturales , Ecosistema , Modelos Teóricos , Modelos Biológicos
9.
Conserv Biol ; 38(2): e14159, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37551769

RESUMEN

Wildlife mortality due to collisions with vehicles (roadkill) is one of the predominant negative effects exerted by roads on many wildlife species. Reducing roadkill is therefore a major component of wildlife conservation. Roadkill is affected by various factors, including road attributes and traffic volume. It is theorized that the effect of traffic volume on roadkill probability should be unimodal. However, empirical evidence for this theory is lacking. Using a large-scale roadkill database of 18 wildlife species in Israel, encompassing 2846 km of roads over 10 years, we explored the effects of traffic volume and road attributes (e.g., road lighting, verge vegetation) on roadkill probability with a multivariate generalized linear mixed model. A unimodal effect of traffic volume was identified for the striped hyena (Hyaena hyaena), whereas 5 species demonstrated a novel quadratic U-shaped effect (e.g., golden jackal [Canis aureus]). Four species showed a negative linear effect (e.g., wild boar [Sus scrofa]). We also identified varying effects of road attributes on roadkill. For instance, road lighting and roadside trees decreased roadkill for several species, whereas bus stops and concrete guardrails led to increased roadkill. The theorized unimodal effect of traffic volume may only apply to large, agile species, and the U-shaped effect could be related to intraspecies variability in traffic avoidance behavior. In general, we found that both high-traffic and low-traffic roads can pose a high mortality risk for wildlife. It is therefore important to monitor roadkill on low-traffic roads and adapt road attributes to mitigate roadkill. Road design for effective roadkill mitigation includes reducing the use of concrete guardrails and median barriers where possible and avoiding dense bushes in verge landscaping. These measures are complemented by employing wildlife detection systems, driver warnings, and seasonal speed reduction measures on low-traffic roads identified as roadkill hotspots.


Riesgo de mortalidad de fauna presentado por las carreteras de mucho y poco tráfico Denneboom et al. 23­229 Resumen La mortalidad de fauna por colisiones con vehículos es uno de los efectos negativos predominantes que tienen las carreteras sobre muchas especies. Por lo tanto, la reducción de esta mortalidad es un componente principal de la conservación de la fauna. Esta mortalidad se ve afectada por varios factores, incluyendo las características de la carretera y el volumen de tráfico. Se piensa que el efecto del volumen de tráfico sobre la probabilidad de las colisiones debería ser unimodal; sin embargo, la evidencia empírica para esta teoría no es suficiente. Usamos una base de datos de colisiones de 18 especies de fauna en Israel que engloba 2,846 km de carreteras durante diez años para explorar con un modelo mixto lineal generalizado multivariado los efectos del volumen de tráfico y las características de la carretera (p. ej., iluminación, vegetación de borde) sobre la probabilidad de colisiones. Identificamos un efecto unimodal del volumen del tráfico para la hiena rayada (Hyaena hyaena), mientras que cinco especies demostraron un efecto cuadrático novedoso en forma de U, como el chacal dorado (Canis aureus). Cuatro especies mostraron un efecto negativo lineal, como el jabalí salvaje (Sus scrofa). También identificamos varios efectos de las características de la carretera sobre las colisiones. Por ejemplo, la iluminación y los árboles en los bordes disminuyeron las colisiones para varias especies, mientras que las paradas de camión y los quitamiedos de concreto resultaron en un incremento de las colisiones. La teoría del efecto unimodal del volumen de tráfico podría aplicar sólo para especies grandes y ágiles, mientras que el efecto en forma de U podría relacionarse con la variabilidad de comportamiento para evitar colisiones que hay entre las especies. En general, descubrimos que tanto las carreteras con poco y mucho tráfico pueden representar un riesgo de mortalidad para la fauna. Por lo tanto, es importante monitorear las colisiones en las carreteras con poco tráfico y adaptar las características de la carretera para mitigar las colisiones. El diseño de las carreteras para una mitigación efectiva incluye reducir el uso de quitamiedos de concreto y barreras centrales en donde sea posible y evitar los arbustos densos en el paisajismo de los bordes. Estas medidas están complementadas con el uso de sistemas de detección de fauna, señalamientos para los conductores y medidas estacionales de reducción de la velocidad en las carreteras de poco tráfico identificadas como puntos calientes de colisiones.


Asunto(s)
Animales Salvajes , Conservación de los Recursos Naturales , Animales , Probabilidad , Accidentes de Tránsito/prevención & control
10.
Proc Natl Acad Sci U S A ; 118(51)2021 12 21.
Artículo en Inglés | MEDLINE | ID: mdl-34911752

RESUMEN

The presence of a single cluster of nonoptimal codons was found to decrease a transcript's half-life through the interaction of the ribosome-associated quality control machinery with stalled ribosomes in Saccharomyces cerevisiae The impact of multiple nonoptimal codon clusters on a transcript's half-life, however, is unknown. Using a kinetic model, we predict that inserting a second nonoptimal cluster near the 5' end can lead to synergistic effects that increase a messenger RNA's (mRNA's) half-life in S. cerevisiae Specifically, the 5' end cluster suppresses the formation of ribosome queues, reducing the interaction of ribosome-associated quality control factors with stalled ribosomes. We experimentally validate this prediction by introducing two nonoptimal clusters into three different genes and find that their mRNA half-life increases up to fourfold. The model also predicts that in the presence of two clusters, the cluster closest to the 5' end is the primary determinant of mRNA half-life. These results suggest the "translational ramp," in which nonoptimal codons are located near the start codon and increase translational efficiency, may have the additional biological benefit of allowing downstream slow-codon clusters to be present without decreasing mRNA half-life. These results indicate that codon usage bias plays a more nuanced role in controlling cellular protein levels than previously thought.


Asunto(s)
Biosíntesis de Proteínas , ARN Mensajero/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas Fúngicas/biosíntesis , Semivida , Modelos Genéticos
11.
Proc Natl Acad Sci U S A ; 118(43)2021 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-34686598

RESUMEN

Phase transitions are emergent phenomena where microscopic interactions drive a disordered system into a collectively ordered phase. Near the boundary between two phases, the system can exhibit critical, scale-invariant behavior. Here, we report on a second-order phase transition accompanied by critical behavior in a system of warm cesium spins driven by linearly polarized light. The ordered phase exhibits macroscopic magnetization when the interactions between the spins become dominant. We measure the phase diagram of the system and observe the collective behavior near the phase boundaries, including power-law dependence of the magnetization and divergence of the susceptibility. Out of equilibrium, we observe a critical slowdown of the spin response time by two orders of magnitude, exceeding 5 s near the phase boundary. This work establishes a controlled platform for investigating equilibrium and nonequilibrium properties of magnetic phases.

12.
J Sports Sci ; 42(15): 1421-1431, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39258624

RESUMEN

The aims were to determine the relationship(s) between match-play external load and post-match neuromuscular fatigue as latent constructs, the contribution of the specific measured variables to these latent constructs, and how these differ between forwards and backs in elite rugby union. Forty-one elite male rugby union players (22 forwards and 19 backs) from the same international rugby union team were tested, with data included from the 2020 and 2021 international seasons (11 matches; 146 player appearances). Player's match-play external loads were quantified using microtechnology (for locomotor activities) and video analysis (for collision actions). Neuromuscular fatigue was quantified using countermovement jump tests on force plates which were conducted ~ 24 to 48 hours pre- and post-match. Partial least squares correlation (PLSC) leave one variable out (LOVO) procedure established the relative variable contribution to both external load (X matrix) and neuromuscular fatigue (Y matrix) constructs. Linear mixed-effects models were then constructed to determine the variance explained by the latent scores applied to the variables representing these constructs. For external load, both locomotor and collision variables were identified for the forwards and the backs, although the identified variables differed between groups. For neuromuscular fatigue, jump height was identified as a high contributor for the forwards and the backs, with concentric impulse and reactive strength index high contributors only for the backs. The explained variance between the external load and neuromuscular fatigue latent constructs at the individual player level was 4.4% and 32.2% in the forwards and the backs models, respectively. This discrepancy may be explained by differences in match-play external loads and/or the specificity of the tests to measure indicators of fatigue. These may differ due to, for example, the activities undertaken in the different positional groups.


Asunto(s)
Fútbol Americano , Fatiga Muscular , Humanos , Masculino , Fatiga Muscular/fisiología , Fútbol Americano/fisiología , Análisis de los Mínimos Cuadrados , Adulto Joven , Conducta Competitiva/fisiología , Rendimiento Atlético/fisiología , Adulto , Grabación en Video
13.
Sensors (Basel) ; 24(19)2024 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-39409231

RESUMEN

Collisions of over-height vehicles with low clearance bridges is commonly encountered worldwide. They have caused damage to bridge structures, interruption to traffic, injuries or even fatalities to road users. To mitigate such risks, passive systems that involve warning gantries, flashing lights and illuminated signage are commonly installed. Semi-active systems using laser- or infrared-based detection systems in conjunction with visual warnings have been implemented. Nevertheless, some drivers ignore these visual warnings and collisions continue to occur. This paper presents a novel concept for a collision prevention system, which makes use of a series of sensor-activated, motorized rumble strips. These rumble strips span across a certain distance ahead of a low clearance bridge. When an over-height vehicle is detected, a mechanism is triggered which elevates the rumble strips. The noise and vibrations produce a vigorous alert to the offending driver. They also increase effective friction of the road surface, thus assisting to slow down the vehicle and shorten the stopping distance. The strips will be lowered after a certain time has elapsed, thus minimizing their effects on other vehicles. This article presents a conceptual framework and quantifies the vibration and noise caused by rumble strips in road tests. Road tests indicated that the vibration level typically exceeded 1 g and noise level reached approximately 90 dB in the cabin of a 3.5-ton truck. Fabrication of a proof-of-concept mechanized rumble strip model was presented and verified in an outdoor environment. The circuitry and mechanical design, and requirements in actual implementation, are discussed. The proposed event-triggered rumble strip system could significantly mitigate over-height vehicle collisions that cause major disruptions and injuries worldwide. Further works, including a comprehensive road test involving various types of vehicles, are envisaged.

14.
Sensors (Basel) ; 24(2)2024 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-38257547

RESUMEN

This paper uses virtual simulations to examine the interaction between autonomous vehicles (AVs) and their surrounding environment. A framework was developed to estimate the environment's complexity by calculating the real-time data processing requirements for AVs to navigate effectively. The VISTA simulator was used to synthesize viewpoints to replicate the captured environment accurately. With an emphasis on static physical features, roadways were dissected into relevant road features (RRFs) and full environment (FE) to study the impact of roadside features on the scene complexity and demonstrate the gravity of wildlife-vehicle collisions (WVCs) on AVs. The results indicate that roadside features substantially increase environmental complexity by up to 400%. Increasing a single lane to the road was observed to increase the processing requirements by 12.3-16.5%. Crest vertical curves decrease data rates due to occlusion challenges, with a reported average of 4.2% data loss, while sag curves can increase the complexity by 7%. In horizontal curves, roadside occlusion contributed to severe loss in road information, leading to a decrease in data rate requirements by as much as 19%. As for weather conditions, heavy rain increased the AV's processing demands by a staggering 240% when compared to normal weather conditions. AV developers and government agencies can exploit the findings of this study to better tailor AV designs and meet the necessary infrastructure requirements.

15.
J Environ Manage ; 354: 120437, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38402787

RESUMEN

While wind power plants are an important contribution to the production of renewable energy to limit climate change, collision mortality from turbines is a danger for birds, including many protected species. To try to mitigate collision risks, automatic detection systems (ADSs) can be deployed on wind power plants; these work by detecting incoming birds using a detection/classification process and triggering a specific reaction (scaring off the bird or shutting down the turbine). Nonetheless, bird fatalities still occur at ADS-equipped wind power plants, which raises the question of the performance of these tools. To date, the lack of a transparent, peer-reviewed experimental process to compare the performance of types of ADS has meant there is no robust protocol to assess these systems. With the aim of filling this gap, we developed two standardized protocols that provide objective and unbiased assessments of the performance of different types of ADS, based on their probability of detecting/classifying birds at risk of collision. Both protocols rely on precise 3D tracking of wild birds by human observers using a laser rangefinder, and the comparison of these tracks with those detected and recorded by an ADS. The first protocol evaluates a system's general performance, generating comparable data for all types of ADS. In this protocol, detection/classification probability is estimated conditional on several abiotic and biotic environmental factors such as bird size, distance from the target, the flight angle and azimuth of the bird, as well as weather conditions. The second protocol aims to verify that the performance of an ADS installed on a given wind power plant complies with its regulatory requirements. In this protocol, detection/classification probability is specifically estimated for a given target species at a given regulatory detection distance. This protocol also estimates the proportion of time an ADS is functional on site over a year, and the proportion of reaction orders successfully operated by wind turbines. These protocols have been field-tested and made publicly available for use by government agencies and wind power plant operators.


Asunto(s)
Aves , Centrales Eléctricas , Animales , Cambio Climático , Probabilidad , Energía Renovable , Humanos
16.
Environ Manage ; 73(2): 365-377, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37294316

RESUMEN

A critical step to design wildlife mitigating measures is the identification of roadkill hotspots. However, the effectiveness of mitigations based on roadkill hotspots depends on whether spatial aggregations are recurrent over time, spatially restricted, and most importantly, shared by species with diverse ecological and functional characteristics. We used a functional group approach to map roadkill hotspots for mammalian species along the BR-101/North RJ, a major road crossing important remnants of the Brazilian Atlantic Forest. We tested if functional groups present distinct hotspot patterns, and if they converge into the same road sectors, in that case, favoring optimal mitigating actions. Roadkill rates were monitored and recorded between October/2014 and September/2018 and species were classified into six functional groups based on their home range, body size, locomotion mode, diet, and forest-dependency. Hotspots along the roads were mapped for comparison of spatial patterns between functional groups. Results demonstrated that the roadkill index varied idiosyncratically for each functional group throughout the months and that no group presented seasonality. Seven hotspots were shared by two or more functional groups, highlighting the importance of these road stretches to regional mammal fauna. Two of the stretches are associated with aquatic areas extending from one side of the road to the other, and the remaining are connected to patches of native vegetation on both sides. This work brings a promising approach, yet hardly used in ecological studies on roads to analyze roadkill dynamics, assigning more importance to ecological instead of taxonomical characteristics, normally used to identify spatiotemporal patterns.


Asunto(s)
Animales Salvajes , Mamíferos , Animales , Brasil , Bosques
17.
Chimia (Aarau) ; 78(1-2): 40-44, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38430062

RESUMEN

The addition of individual quanta of rotational excitation to a molecule has been shown to markedly change its reactivity by significantly modifying the intermolecular interactions. So far, it has only been possible to observe these rotational effects in a very limited number of systems due to lack of rotational selectivity in chemical reaction experiments. The recent development of rotationally controlled molecular beams now makes such investigations possible for a wide range of systems. This is particularly crucial in order to understand the chemistry occurring in the interstellar medium, such as exploring the formation of carbon-based astrochemical molecules and the emergence of molecular complexity in interstellar space from the reaction of small atomic and molecular fragments.

18.
Entropy (Basel) ; 26(2)2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38392422

RESUMEN

We investigate the effects of boost invariance breaking on the isotropization of pressure in the glasma, using a 3+1D glasma simulation. The breaking is attributed to spatial fluctuations in the classical color charge density along the collision axis. We present numerical results for pressure and energy density at mid-rapidity and across a wider rapidity region. It is found that, despite varying longitudinal correlation lengths, the behaviors of the pressure isotropizations are qualitatively similar. The numerical results suggest that, in the initial stage, longitudinal color electromagnetic fields develop, similar to those in the boost invariant glasma. Subsequently, these fields evolve into a dilute glasma, expanding longitudinally in a manner akin to a dilute gas. We also show that the energy density at mid-rapidity exhibits a 1/τ decay in the dilute glasma stage.

19.
Wiad Lek ; 77(1): 126-134, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38431817

RESUMEN

OBJECTIVE: Aim: To determine the problematic issues of ensuring the rights and freedoms of persons suffering from mental disorders and to whom CMM are applied in criminal proceedings under the legislation of Ukraine and the legislation of the states that adhere to the modern concepts of international standards of human rights ensuring to a person the CMM are applied to. PATIENTS AND METHODS: Materials and Methods: Legal positions of the ECHR, criminal procedural legislation of a number of states, and a survey of scientists and practitioners conducted by the authors are used in this paper (total number of respondents was 168). A set of general scientific and special methods are used to achieve the aim of the study. CONCLUSION: Conclusions: The practice of applying СMM to persons suffering from mental disorders in criminal proceedings in Ukraine and other states does not fully meet international standards and needs improvement. It was suggested to make changes to the legal acts on the use of CMM in criminal proceedings.


Asunto(s)
Criminales , Trastornos Mentales , Médicos , Humanos , Derechos Humanos , Ucrania , Trastornos Mentales/terapia
20.
Angew Chem Int Ed Engl ; 63(39): e202405371, 2024 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-38965044

RESUMEN

Spillover of adsorbed species from one active site to another is a key step in heterogeneous catalysis. However, the factors controlling this step, particularly the spillover of polyatomic species, have rarely been studied. Herein, we investigate the spillover dynamics of H* and CH3* species on a single-atom alloy surface (Rh/Cu(111)) upon the dissociative chemisorption of methane (CH4), using molecular dynamics that considers both surface phonons and electron-hole pairs. These dynamical calculations are made possible by a high-dimensional potential energy surface machine learned from density functional theory data. Our results provide compelling evidence that the H* and CH3* can spill over on the metal surface at experimental temperatures and reveal novel dynamical features involving an internal motion during diffusion for CH3*. Increasing surface temperature has a minor effect on promoting spillover, as geminate recombinative desorption becomes more prevalent. However, the poisoning of the active site can be mitigated by the frequent gaseous molecular collisions that occur under ambient pressure in real-world catalysis, which transfer energy to the trapped adsorbates. Interestingly, the bulky CH3* exhibits a significant spillover advantage over the light H* due to its larger size, which facilitates energy acquisition. These insights help to advance our understanding of spillover in heterogeneous catalysis.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA