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1.
Environ Sci Technol ; 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39007544

RESUMO

A stylized macro-scale energy model of least-cost electricity systems relying only on wind and solar generation was used to assess the value of different storage technologies, individually and combined, for the contiguous U.S. as well as for four geographically diverse U.S. load-balancing regions. For the contiguous U.S. system, at current costs, when only one storage technology was deployed, hydrogen energy storage produced the lowest system costs, due to its energy-capacity costs being the lowest of all storage technologies modeled. Additional hypothetical storage technologies were more cost-competitive than hydrogen (long-duration storage) only at very low energy-capacity costs, but they were more cost-competitive than Li-ion batteries (short-duration storage) at relatively high energy- and power-capacity costs. In all load-balancing regions investigated, the least-cost systems that included long-duration storage had sufficient energy and power capacity to also meet short-duration energy and power storage needs, so that the addition of short-duration storage as a second storage technology did not markedly reduce total system costs. Thus, in electricity systems that rely on wind and solar generation, contingent on social and geographic constraints, long-duration storage may cost-effectively provide the services that would otherwise be provided by shorter-duration storage technologies.

2.
Annu Rev Microbiol ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39018471

RESUMO

The micronutrient iron is essential for phytoplankton growth due to its central role in a wide variety of key metabolic processes including photosynthesis and nitrate assimilation. As a result of scarce bioavailable iron in seawater, marine primary productivity is often iron-limited with future iron supplies remaining uncertain. Although evolutionary constraints resulted in high cellular iron requirements, phytoplankton evolved diverse mechanisms that enable uptake of multiple forms of iron, storage of iron over short and long timescales, and modulation of their iron requirement under stress. Genomics continues to increase our understanding of iron-related proteins that are homologous to those characterized in other model organisms, while recently, molecular and cell biology is revealing unique genes and processes with connections to iron acquisition or use. Moreover, there are an increasing number of examples showing the interplay between iron uptake and extracellular processes such as boundary layer chemistry and microbial interactions.

3.
Environ Microbiol Rep ; 16(4): e13312, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39049182

RESUMO

Biological nitrogen fixation provides fixed nitrogen for microbes living in the oligotrophic open ocean. UCYN-A2, the previously known symbiont of Braarudosphaera bigelowii, now believed to be an early-stage B. bigelowii organelle that exchanges fixed nitrogen for fixed carbon, is globally distributed. Indirect evidence suggested that B. bigelowii might be a mixotrophic (phagotrophic) phototrophic flagellate. The goal of this study was to determine if B. bigelowii can graze on bacteria using several independent approaches. The results showed that B. bigelowii grazed on co-occurring bacteria at a rate of 5-7 cells/h/B. bigelowii and that the overall grazing rate was significantly higher at nighttime than at daytime. Bacterial abundance changes, assessed with 16S rRNA gene amplicon sequencing analysis, may have indicated preferential grazing by B. bigelowii on specific bacterial genotypes. In addition, Lysotracker™ staining of B. bigelowii suggested digestive activity inside B. bigelowii. Carbon and nitrogen fixation measurements revealed that the carbon demand of B. bigelowii could not be fulfilled by photosynthesis alone, implying supplementation by heterotrophy. These independent lines of evidence together revealed that B. bigelowii engages in phagotrophy, which, beyond serving as a supplementary source of carbon and energy, may also facilitate the indirect assimilation of inorganic nutrients.


Assuntos
Haptófitas , Fixação de Nitrogênio , Simbiose , Haptófitas/metabolismo , Haptófitas/crescimento & desenvolvimento , Haptófitas/fisiologia , Nitrogênio/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Bactérias/isolamento & purificação , Carbono/metabolismo , RNA Ribossômico 16S/genética , Fagocitose , Filogenia
4.
Microvasc Res ; 155: 104706, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38871050

RESUMO

Prior work has yet to determine whether the reduction of dietary nitrate (NO3-) to NO, via the enterosalivary pathway, may modify cutaneous vascular conductance (CVC) responses to local heating in older women. Changes occurring with the transition to menopause related to hormonal flux, increased adiposity, and/or decreased physical activity may further compound the negative influence of aging on nitric oxide (NO)-dependent CVC. Herein, we characterized changes in NO-dependent CVC following acute ingestion of 140 mL of NO3--rich beetroot juice in 24 older women (age: 65 ± 5 y, BMI: 31.2 ± 3.7 kg/m2). Red blood cell (RBC) flux was measured continuously via laser-Doppler flowmetry on the dorsal aspect of the forearm during local skin heating to 39 °C/44 °C before and 3 h after NO3- ingestion. NO-dependent changes in CVC were calculated as RBC flux/mean arterial blood pressure at 39 °C and normalized as a proportion of maximal CVC at 44 °C (%CVCmax). Changes (Δ) in fractional exhaled NO (FeNO) following NO3- ingestion were used an index of NO bioavailability. Despite increased FeNO (+81 ± 70 %, P < 0.001), %CVCmax at 39 °C was reduced (-16 ± 10 %, P < 0.001) following NO3- ingestion. A greater reduction in %CVCmax was weakly to moderately associated with higher body fat% (r = 0.45 [0.05-0.72], P = 0.029), central adiposity% (r = 0.50 [0.13-0.75], P = 0.012), neutrophil% (r = 0.42 [0.02-0.70], P = 0.041), and higher neutrophil to lymphocyte ratio (r = 0.49 [0.11-0.75], P = 0.016). These findings demonstrate a single dose of dietary NO3- does not promote CVC responses to local heating in sedentary older women with overweight and obesity. Correlation with multiple biomarkers suggest systemic inflammation may be involved.

5.
EMBO J ; 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38907032

RESUMO

Dynamin 1 mediates fission of endocytic synaptic vesicles in the brain and has two major splice variants, Dyn1xA and Dyn1xB, which are nearly identical apart from the extended C-terminal region of Dyn1xA. Despite a similar set of binding partners, only Dyn1xA is enriched at endocytic zones and accelerates vesicle fission during ultrafast endocytosis. Here, we report that Dyn1xA achieves this localization by preferentially binding to Endophilin A1 through a newly defined binding site within its long C-terminal tail extension. Endophilin A1 binds this site at higher affinity than the previously reported site, and the affinity is determined by amino acids within the Dyn1xA tail but outside the binding site. This interaction is regulated by the phosphorylation state of two serine residues specific to the Dyn1xA variant. Dyn1xA and Endophilin A1 colocalize in patches near the active zone, and mutations disrupting Endophilin A binding to the long tail cause Dyn1xA mislocalization and stalled endocytic pits on the plasma membrane during ultrafast endocytosis. Together, these data suggest that the specificity for ultrafast endocytosis is defined by the phosphorylation-regulated interaction of Endophilin A1 with the C-terminal extension of Dyn1xA.

6.
J Surg Orthop Adv ; 33(1): 49-52, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38815079

RESUMO

Children with cerebral palsy (CP) and those with avascular necosis (AVN) after treatment of developmental hip dysplasia (DDH) are at risk of developing coxa valga. Proximal femur guided growth is a minimally invasive option to correct this deformity. A systematic review of articles that described treatment of coxa valga with proximal femur guided growth (PFGG) and reporting on primary radiographic outcomes, demographic variables, surgical variables and complications. One hundred and seventy-nine hips underwent PFGG (117 with CP and 62 with lateral overgrowth). Average age at surgery was 8.1 years; average follow-up was 52.5 months. Migration percentage improved from 11.2% (p < 0.0001). Neck-shaft angle improved by 11.9° (p < 0.0001). The most common complication was screw growth out of the physis (30% of cases). PFGG can correct coxa valga, improve radiographic parameters, and in children with CP prevent further subluxation. This technique modulates proximal femur growth, induces changes to the acetabulum and can correct valgus deformity. Evidence Level III. (Journal of Surgical Orthopaedic Advances 32(4):049-052, 2024).


Assuntos
Paralisia Cerebral , Fêmur , Humanos , Criança , Fêmur/diagnóstico por imagem , Coxa Valga/diagnóstico por imagem , Coxa Valga/etiologia , Displasia do Desenvolvimento do Quadril/cirurgia , Displasia do Desenvolvimento do Quadril/diagnóstico por imagem , Luxação Congênita de Quadril/cirurgia , Luxação Congênita de Quadril/diagnóstico por imagem
7.
Ergonomics ; : 1-10, 2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38613402

RESUMO

Head-up displays (HUDs) have the potential to change work in operation environments by providing hands-free information to wearers. However, these benefits may be accompanied by trade-offs, primarily by increasing cognitive load due to dividing attention. Previous studies have attempted to understand the trade-offs of HUD usage; however, all of which were focused on land-based tasks. A gap in understanding exists when examining HUD use in aquatic environments as immersion introduces unique environmental and physiological factors that could affect multitasking. In this study, we investigated multitasking performance associated with swimming with a HUD. Eighteen participants completed three tasks: swimming only, a HUD-administered word recall task, and a dual-task combining both tasks. Results revealed significant dual-task interference in both tasks, though possibly less pronounced than in land-based tasks. These findings enhance not only help characterise dual-task performance, but also offer valuable insights for HUD design for aquatic settings.


HUDs have become an increasingly popular tool to present information to users in complex working environments. However, past research examining HUD task performance has been restricted to land-based contexts. The current study examines HUD use while swimming and provides characterisation of multitasking performance within aquatic environments.

8.
Science ; 384(6692): 217-222, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38603509

RESUMO

Symbiotic interactions were key to the evolution of chloroplast and mitochondria organelles, which mediate carbon and energy metabolism in eukaryotes. Biological nitrogen fixation, the reduction of abundant atmospheric nitrogen gas (N2) to biologically available ammonia, is a key metabolic process performed exclusively by prokaryotes. Candidatus Atelocyanobacterium thalassa, or UCYN-A, is a metabolically streamlined N2-fixing cyanobacterium previously reported to be an endosymbiont of a marine unicellular alga. Here we show that UCYN-A has been tightly integrated into algal cell architecture and organellar division and that it imports proteins encoded by the algal genome. These are characteristics of organelles and show that UCYN-A has evolved beyond endosymbiosis and functions as an early evolutionary stage N2-fixing organelle, or "nitroplast."


Assuntos
Cianobactérias , Haptófitas , Mitocôndrias , Fixação de Nitrogênio , Nitrogênio , Cianobactérias/genética , Cianobactérias/metabolismo , Haptófitas/microbiologia , Nitrogênio/metabolismo , Fixação de Nitrogênio/genética , Água do Mar/microbiologia , Simbiose , Mitocôndrias/metabolismo , Cloroplastos/metabolismo
9.
ISME J ; 18(1)2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38624181

RESUMO

Iron is an essential nutrient for all microorganisms of the marine environment. Iron limitation of primary production has been well documented across a significant portion of the global surface ocean, but much less is known regarding the potential for iron limitation of the marine heterotrophic microbial community. In this work, we characterize the transcriptomic response of the heterotrophic bacterial community to iron additions in the California Current System, an eastern boundary upwelling system, to detect in situ iron stress of heterotrophic bacteria. Changes in gene expression in response to iron availability by heterotrophic bacteria were detected under conditions of high productivity when carbon limitation was relieved but when iron availability remained low. The ratio of particulate organic carbon to dissolved iron emerged as a biogeochemical proxy for iron limitation of heterotrophic bacteria in this system. Iron stress was characterized by high expression levels of iron transport pathways and decreased expression of iron-containing enzymes involved in carbon metabolism, where a majority of the heterotrophic bacterial iron requirement resides. Expression of iron stress biomarkers, as identified in the iron-addition experiments, was also detected insitu. These results suggest iron availability will impact the processing of organic matter by heterotrophic bacteria with potential consequences for the marine biological carbon pump.


Assuntos
Bactérias , Carbono , Processos Heterotróficos , Ferro , Água do Mar , Ferro/metabolismo , Carbono/metabolismo , Bactérias/metabolismo , Bactérias/genética , Bactérias/classificação , Bactérias/isolamento & purificação , Água do Mar/microbiologia , California , Microbiota
10.
Environ Microbiol ; 26(3): e16616, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38517638

RESUMO

Nitrification is an important control on the form and distribution of nitrogen in freshwater ecosystems. However, the seasonality of nitrogen pools and the diversity of organisms catalyzing this process have not been well documented in oligotrophic lakes. Here, we show that nitrogen pools and nitrifying organisms in Flathead Lake are temporally and vertically dynamic, with nitrifiers displaying specific preferences depending on the season. While the ammonia-oxidizing bacteria (AOB) Nitrosomonadaceae and nitrite-oxidizing bacteria (NOB) Nitrotoga dominate at depth in the summer, the ammonia-oxidizing archaea (AOA) Nitrososphaerota and NOB Nitrospirota become abundant in the winter. Given clear seasonality in ammonium, with higher concentrations during the summer, we hypothesize that the succession between these two nitrifying groups may be due to nitrogen affinity, with AOB more competitive when ammonia concentrations are higher and AOA when they are lower. Nitrifiers in Flathead Lake share more than 99% average nucleotide identity with those reported in other North American lakes but are distinct from those in Europe and Asia, indicating a role for geographic isolation as a factor controlling speciation among nitrifiers. Our study shows there are seasonal shifts in nitrogen pools and nitrifying populations, highlighting the dynamic spatial and temporal nature of nitrogen cycling in freshwater ecosystems.


Assuntos
Lagos , Nitrosomonadaceae , Lagos/microbiologia , Estações do Ano , Ecossistema , Amônia , Oxirredução , Archaea/genética , Nitrificação , Nitritos , Nitrogênio , Dinâmica Populacional , Filogenia
11.
Pediatr Cardiol ; 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38427088

RESUMO

Pediatric cardiology fellows receive limited training on delivering serious news. This is a teachable skill through simulation-based communication. While studies have shown the use of communication courses in pediatrics, there have been none in pediatric cardiology. Pediatric cardiologists recognize the importance of good communication and desire further development of these skills. Based on an internal needs assessment, three cases were developed; fetal hypoplastic left heart syndrome, teenager with new hypertrophic cardiomyopathy, and young-adult with Fontan failure. A 4-h simulation course using evidence-based methods to teach delivering serious news was designed, consisting of a didactic session, case demonstration and small group case-based encounters with simulated patients. Trainees completed standardized pre/post-course surveys to assess perception of skill and preparedness. Paired survey responses were compared. Six pediatric cardiology fellows participated. Only 33% had received formal training in delivering serious news and 17% in techniques of responding to patient's emotions. The proportion of participants who felt good about their ability to deliver serious news and deal with a family's emotions increased from 0 to 83%. The proportion of participants who felt prepared to provide serious news about a patient's illness increased from 17 to 67%. Given the small number of participants, results were not statistically significant. All participants felt that the course was valuable in improving communication skills. A formal communication course increased perception of skill and preparedness among trainees. We provide an evidence-based framework and clinical cases for delivering serious news in pediatric cardiology, which is generalizable to other training programs.

12.
Can J Cardiol ; 40(1): 58-72, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37290536

RESUMO

BACKGROUND: Patients with multisystem inflammatory syndrome in children (MIS-C) and Kawasaki disease (KD) have overlapping clinical features. We compared demographics, clinical presentation, management, and outcomes of patients according to evidence of previous SARS-CoV-2 infection. METHODS: The International Kawasaki Disease Registry (IKDR) enrolled KD and MIS-C patients from sites in North, Central, and South America, Europe, Asia, and the Middle East. Evidence of previous infection was defined as: Positive (household contact or positive polymerase chain reaction [PCR]/serology), Possible (suggestive clinical features of MIS-C and/or KD with negative PCR or serology but not both), Negative (negative PCR and serology and no known exposure), and Unknown (incomplete testing and no known exposure). RESULTS: Of 2345 enrolled patients SARS-CoV-2 status was Positive for 1541 (66%) patients, Possible for 89 (4%), Negative for 404 (17%) and Unknown for 311 (13%). Clinical outcomes varied significantly among the groups, with more patients in the Positive/Possible groups presenting with shock, having admission to intensive care, receiving inotropic support, and having longer hospital stays. Regarding cardiac abnormalities, patients in the Positive/Possible groups had a higher prevalence of left ventricular dysfunction, and patients in the Negative and Unknown groups had more severe coronary artery abnormalities. CONCLUSIONS: There appears to be a spectrum of clinical features from MIS-C to KD with a great deal of heterogeneity, and one primary differentiating factor is evidence for previous acute SARS-CoV-2 infection/exposure. SARS-CoV-2 Positive/Possible patients had more severe presentations and required more intensive management, with a greater likelihood of ventricular dysfunction but less severe coronary artery adverse outcomes, in keeping with MIS-C.


Assuntos
COVID-19 , Síndrome de Linfonodos Mucocutâneos , Síndrome de Resposta Inflamatória Sistêmica , Criança , Humanos , COVID-19/epidemiologia , SARS-CoV-2 , Síndrome de Linfonodos Mucocutâneos/diagnóstico , Síndrome de Linfonodos Mucocutâneos/epidemiologia , Síndrome de Linfonodos Mucocutâneos/terapia , Sistema de Registros
13.
JAMA Netw Open ; 6(12): e2346829, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38064213

RESUMO

Importance: Obesity may affect the clinical course of Kawasaki disease (KD) in children and multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. Objective: To compare the prevalence of obesity and associations with clinical outcomes in patients with KD or MIS-C. Design, Setting, and Participants: In this cohort study, analysis of International Kawasaki Disease Registry (IKDR) data on contemporaneous patients was conducted between January 1, 2020, and July 31, 2022 (42 sites, 8 countries). Patients with MIS-C (defined by Centers for Disease Control and Prevention criteria) and patients with KD (defined by American Heart Association criteria) were included. Patients with KD who had evidence of a recent COVID-19 infection or missing or unknown COVID-19 status were excluded. Main Outcomes and Measures: Patient demographic characteristics, clinical features, disease course, and outcome variables were collected from the IKDR data set. Using body mass index (BMI)/weight z score percentile equivalents, patient weight was categorized as normal weight (BMI <85th percentile), overweight (BMI ≥85th to <95th percentile), and obese (BMI ≥95th percentile). The association between adiposity category and clinical features and outcomes was determined separately for KD and MIS-C patient groups. Results: Of 1767 children, 338 with KD (median age, 2.5 [IQR, 1.2-5.0] years; 60.4% male) and 1429 with MIS-C (median age, 8.7 [IQR, 5.3-12.4] years; 61.4% male) were contemporaneously included in the study. For patients with MIS-C vs KD, the prevalence of overweight (17.1% vs 11.5%) and obesity (23.7% vs 11.5%) was significantly higher (P < .001), with significantly higher adiposity z scores, even after adjustment for age, sex, and race and ethnicity. For patients with KD, apart from intensive care unit admission rate, adiposity category was not associated with laboratory test features or outcomes. For patients with MIS-C, higher adiposity category was associated with worse laboratory test values and outcomes, including a greater likelihood of shock, intensive care unit admission and inotrope requirement, and increased inflammatory markers, creatinine levels, and alanine aminotransferase levels. Adiposity category was not associated with coronary artery abnormalities for either MIS-C or KD. Conclusions and Relevance: In this international cohort study, obesity was more prevalent for patients with MIS-C vs KD, and associated with more severe presentation, laboratory test features, and outcomes. These findings suggest that obesity as a comorbid factor should be considered at the clinical presentation in children with MIS-C.


Assuntos
COVID-19 , Síndrome de Linfonodos Mucocutâneos , Criança , Estados Unidos/epidemiologia , Humanos , Masculino , Pré-Escolar , Feminino , COVID-19/epidemiologia , Síndrome de Linfonodos Mucocutâneos/complicações , Síndrome de Linfonodos Mucocutâneos/epidemiologia , SARS-CoV-2 , Estudos de Coortes , Sobrepeso , Obesidade/complicações , Obesidade/epidemiologia
14.
Pediatr Cardiol ; 2023 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-38157048

RESUMO

Kawasaki disease (KD) and Multisystem Inflammatory Syndrome in Children (MIS-C) associated with COVID-19 show clinical overlap and both lack definitive diagnostic testing, making differentiation challenging. We sought to determine how cardiac biomarkers might differentiate KD from MIS-C. The International Kawasaki Disease Registry enrolled contemporaneous KD and MIS-C pediatric patients from 42 sites from January 2020 through June 2022. The study population included 118 KD patients who met American Heart Association KD criteria and compared them to 946 MIS-C patients who met 2020 Centers for Disease Control and Prevention case definition. All included patients had at least one measurement of amino-terminal prohormone brain natriuretic peptide (NTproBNP) or cardiac troponin I (TnI), and echocardiography. Regression analyses were used to determine associations between cardiac biomarker levels, diagnosis, and cardiac involvement. Higher NTproBNP (≥ 1500 ng/L) and TnI (≥ 20 ng/L) at presentation were associated with MIS-C versus KD with specificity of 77 and 89%, respectively. Higher biomarker levels were associated with shock and intensive care unit admission; higher NTproBNP was associated with longer hospital length of stay. Lower left ventricular ejection fraction, more pronounced for MIS-C, was also associated with higher biomarker levels. Coronary artery involvement was not associated with either biomarker. Higher NTproBNP and TnI levels are suggestive of MIS-C versus KD and may be clinically useful in their differentiation. Consideration might be given to their inclusion in the routine evaluation of both conditions.

15.
Hum Factors ; : 187208231209151, 2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-37956865

RESUMO

OBJECTIVE: This study aimed to assess the plausibility of self-control depletion, or ego-depletion, as the underlying cognitive resource responsible for performance decrements on the sustained attention to response task. BACKGROUND: Researchers suggested that self-control is a limited cognitive resource used to complete a myriad of processes, including sustained attention. Past research showed that trait self-control affects some sustained attention tasks. However, little research has investigated the effect of self-control as a limited cognitive resource that varies over time (i.e., as a state-dependent variable). METHODS: This experiment investigated the effect of self-control (trait and state) on a sustained motor-inhibition task (e.g., sustained attention to response task; SART). State self-control was manipulated using a between-subjects design-participants in the experimental condition completed a task designed to deplete state self-control prior to performing the SART while the control condition completed a modified version that did not deplete self-control. RESULTS: Trait self-control predicted performance on the SART, but the depletion task (state self-control) had no detectable effect. CONCLUSION: Given the evidence, it is unlikely that state self-control plays a causal role in performance decrements in the SART, but there appears to be some association between performance on the SART and trait self-control. APPLICATION: Trait self-control ought to be considered in future work for personnel selection in real-world tasks that the SART models such as long-distance driving, air traffic control, and TSA operations.

16.
Nat Commun ; 14(1): 7215, 2023 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-37940668

RESUMO

Coastal upwelling regions are among the most productive marine ecosystems but may be threatened by amplified ocean acidification. Increased acidification is hypothesized to reduce iron bioavailability for phytoplankton thereby expanding iron limitation and impacting primary production. Here we show from community to molecular levels that phytoplankton in an upwelling region respond to short-term acidification exposure with iron uptake pathways and strategies that reduce cellular iron demand. A combined physiological and multi-omics approach was applied to trace metal clean incubations that introduced 1200 ppm CO2 for up to four days. Although variable, molecular-level responses indicate a prioritization of iron uptake pathways that are less hindered by acidification and reductions in iron utilization. Growth, nutrient uptake, and community compositions remained largely unaffected suggesting that these mechanisms may confer short-term resistance to acidification; however, we speculate that cellular iron demand is only temporarily satisfied, and longer-term acidification exposure without increased iron inputs may result in increased iron stress.


Assuntos
Fitoplâncton , Água do Mar , Fitoplâncton/metabolismo , Ecossistema , Concentração de Íons de Hidrogênio , Ferro/metabolismo
17.
Evol Appl ; 16(8): 1412-1421, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37622094

RESUMO

Polyandrous mating systems result in females mating with multiple males, generating opportunities for strong pre-mating and post-mating sexual selection. Polyandry also creates the potential for unintended matings and subsequent sperm competition with hybridizing species. Cryptic female choice allows females to bias paternity towards preferred males under sperm competition and may include conspecific sperm preference when under hybridization risk. The potential for hybridization becomes particularly important in context of invasive species that can novelly hybridize with natives, and by definition, have evolved allopatrically. We provide the first examination of conspecific sperm preference in a system of three species with the potential to hybridize: North American native Atlantic salmon (Salmo salar) and brook char (Salvelinus fontinalis), and invasive brown trout (Salmo trutta) from Europe. Using naturalized populations on the island of Newfoundland, we measured changes in sperm swimming performance, a known predictor of paternity, to determine the degree of modification in sperm swimming to female cues related to conspecific sperm preference. Compared to water alone, female ovarian fluid in general had a pronounced effect and changed sperm motility (by a mean of 53%) and swimming velocity (mean 30%), but not linearity (mean 6%). However, patterns in the degree of modification suggest there is no conspecific sperm preference in the North American populations. Furthermore, female cues from both native species tended to boost the sperm of invasive males more than their own. We conclude that cryptic female choice via ovarian fluid mediated sperm swimming modification is too weak in this system to prevent invasive hybridization and is likely insufficient to promote or maintain reproductive isolation between the native North American species.

18.
Br J Anaesth ; 131(2): 205-208, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37330308

RESUMO

Postoperative delirium is a particularly debilitating complication of surgery and perioperative care. Although the aetiology of postoperative delirium is not entirely understood, recent evidence suggests that Alzheimer's disease and related dementias pathology plays an important role in the development of postoperative delirium. A recent study evaluating postoperative changes in plasma beta amyloid (Aß) levels found increased Aß across the postoperative period, but the association with postoperative delirium incidence and severity was variable. These findings support the idea that Alzheimer's disease and related dementias pathology in combination with blood-brain barrier dysfunction and neuroinflammation may impart risk for postoperative delirium.


Assuntos
Doença de Alzheimer , Delírio do Despertar , Humanos , Peptídeos beta-Amiloides , Doença de Alzheimer/patologia , Barreira Hematoencefálica , Crime
19.
Nat Commun ; 14(1): 2888, 2023 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-37210439

RESUMO

Compensatory endocytosis keeps the membrane surface area of secretory cells constant following exocytosis. At chemical synapses, clathrin-independent ultrafast endocytosis maintains such homeostasis. This endocytic pathway is temporally and spatially coupled to exocytosis; it initiates within 50 ms at the region immediately next to the active zone where vesicles fuse. However, the coupling mechanism is unknown. Here, we demonstrate that filamentous actin is organized as a ring, surrounding the active zone at mouse hippocampal synapses. Assuming the membrane area conservation is due to this actin ring, our theoretical model suggests that flattening of fused vesicles exerts lateral compression in the plasma membrane, resulting in rapid formation of endocytic pits at the border between the active zone and the surrounding actin-enriched region. Consistent with model predictions, our data show that ultrafast endocytosis requires sufficient compression by exocytosis of multiple vesicles and does not initiate when actin organization is disrupted, either pharmacologically or by ablation of the actin-binding protein Epsin1. Our work suggests that membrane mechanics underlie the rapid coupling of exocytosis to endocytosis at synapses.


Assuntos
Actinas , Vesículas Sinápticas , Animais , Camundongos , Vesículas Sinápticas/metabolismo , Actinas/metabolismo , Sinapses/metabolismo , Endocitose , Membrana Celular/metabolismo , Exocitose
20.
Proc Natl Acad Sci U S A ; 120(21): e2207185120, 2023 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-37192169

RESUMO

Collecting complete network data is expensive, time-consuming, and often infeasible. Aggregated Relational Data (ARD), which ask respondents questions of the form "How many people with trait X do you know?" provide a low-cost option when collecting complete network data is not possible. Rather than asking about connections between each pair of individuals directly, ARD collect the number of contacts the respondent knows with a given trait. Despite widespread use and a growing literature on ARD methodology, there is still no systematic understanding of when and why ARD should accurately recover features of the unobserved network. This paper provides such a characterization by deriving conditions under which statistics about the unobserved network (or functions of these statistics like regression coefficients) can be consistently estimated using ARD. We first provide consistent estimates of network model parameters for three commonly used probabilistic models: the beta-model with node-specific unobserved effects, the stochastic block model with unobserved community structure, and latent geometric space models with unobserved latent locations. A key observation is that cross-group link probabilities for a collection of (possibly unobserved) groups identify the model parameters, meaning ARD are sufficient for parameter estimation. With these estimated parameters, it is possible to simulate graphs from the fitted distribution and analyze the distribution of network statistics. We can then characterize conditions under which the simulated networks based on ARD will allow for consistent estimation of the unobserved network statistics, such as eigenvector centrality, or response functions by or of the unobserved network, such as regression coefficients.

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