Intermediate Age Research Articles

P46: Subjective cognitive decline and frailty status: results from the Compostela Ageing Study.

Objective:The relationship between objective cognitive performance and physical frailty has been explored in the recent literature and cognitive frailty has emerged as a strong field of study in psychogerontology. However, less is known about the relationship between subjective cognitive status and physical frailty. The aim of this communication is to present the relationships found between subjective cognitive decline and physical frailty in the third wave of the Compostela Aging Study, the first in which frailty status has been studied.Methods:Cognitive and neuropsychological, functional, and affective assessment was conducted with persons over 50 years of age with subjective memory complaints in the health area of Santiago de Compostela. 149 participants who completed the third wave of the study and who did not present dementia or other serious pathologies were selected. Mild Cognitive Impairment (MCI) was diagnosed according to the current criteria in a special meeting of the research team. In the participants without MCI, the intensity and severity of their complaints were assessed according to the Subjective Cognitive Decline (SCD) criteria. Physical frailty was assessed following the frailty phenotype as described by Fried et al.Results:Only 4 participants (2.7%) presented physical frailty (3, 4 or 5 criteria in the frailty phenotype). Of those presenting physical pre-frailty (1 or 2 criteria), 36 were MCI (23.8%), 33 SCD (21.9%) and 36 controls. Finally, 40 participants (26.5%) presented no frailty criteria (8 with MCI, 13 with SCD and 19 controls). Participants with SCD and pre-frailty were of intermediate age and they had more years of education than the group with MCI and pre-frailty, although these differences were not significant. They have significantly more symptoms of depression (GDS) and worse mental health status (GHQ-12) than participants without frailty and pre-frailty controls, and more symptoms of anxiety (GAD-7) than participants without frailty.Conclusion:The relationship between subjective memory complaints and frailty could help to establish groups at special risk of cognitive impairment in phases prior to objective cognitive decline, being these groups particularly optimal targets for preventive intervention. However, a detailed characterization of these subgroups is still required.

Carbon dynamics of prescribed fire in pine- and oak-dominated forests on the mid-Atlantic coastal plain, USA

The use of prescribed fire to reduce the risk of wildfires and maintain or enhance desired ecological conditions is increasing in forests of the Mid-Atlantic region. Accurate estimates of forest carbon (C) dynamics associated with prescribed burning, including net ecosystem productivity (NEP) and time to accumulate the C lost during burns, termed neutral net ecosystem C balance (NECB), as a function of fire intensity and burn intervals would assist fire managers optimize treatment timing while balancing other ecosystem services provided by forests. We quantified forest C dynamics and evapotranspiration in two pine- and oak-dominated forests in the Pinelands National Reserve of southern New Jersey that have been managed using prescribed fire over two decades. Using long-term C flux data, we found that NEP, ecosystem respiration (RE) and gross ecosystem production (GEP) were similar among stands during undisturbed years. Estimated C loss during three prescribed burns at the pine-dominated stand averaged 4.3 ± 0.9 Mg C ha-1, which is equivalent to 2–3 years of NEP during undisturbed years, and consistent with fuel consumption during prescribed burns throughout the Pinelands. Only annual NEP was lower during years when burns were conducted compared to unburned years, while annual RE, GEP, evapotranspiration and ecosystem water use efficiency were similar. Over a two-decade period, NEP totaled 28.3 Mg C ha-1 and NECB was 15.5 Mg C ha-1, indicating that stands managed using repeated prescribed burns still sequester moderate amounts of C. At an oak-dominated stand, a prescribed burn released lower amounts of C (1.7 Mg C ha-1), and annual NEP was greater over the following 3-year period compared to a decade of low annual NEP following severe spongy moth defoliation and associated tree mortality, suggesting that prescribed fires could play a role in the restoration of ecosystem functioning in insect-damaged stands. Patterns of forest C dynamics during and following prescribed burns in these mid-Atlantic forests are similar to intermediate age pine-dominated stands throughout the southeastern USA, which also sequester moderate amounts of C through repeated prescribed burning regimes.

AGN feedback and star formation in the peculiar galaxy NGC 232: insights from VLT-MUSE observations

ABSTRACT We use VLT-MUSE integral field unit data to study the ionized gas physical properties and kinematics as well as the stellar populations of the Seyfert 2 galaxy NGC 232 as an opportunity to understand the role of AGN feedback on star formation. The data cover a field of view of 60 × 60 arcsec2 at a spatial resolution of ∼850 pc. The emission-line profiles have been fitted with two Gaussian components, one associated to the emission of the gas in the disc and the other due to a bi-conical outflow. The spectral synthesis suggests a predominantly old stellar population with ages exceeding 2 Gyr, with the largest contributions seen at the nucleus and decreasing outwards. Meanwhile, the young and intermediate age stellar populations exhibit a positive gradient with increasing radius and a circum-nuclear star-forming ring with radius of ∼0.5 kpc traced by stars younger than 20 Myr, is observed. This, along with the fact that AGN and SF dominated regions present similar gaseous oxygen abundances, suggests a shared reservoir feeding both star formation and the AGN. We have estimated a maximum outflow rate in ionized gas of ∼1.26 M⊙ yr−1 observed at a distance of ∼560 pc from the nucleus. The corresponding maximum kinetic power of the outflow is ∼3.4 × 1041 erg s−1. This released energy could be sufficient to suppress star formation within the ionization cone, as evidenced by the lower star formation rates observed in this region.

Identification of biologic-responsive phenotypes in elderly people with eosinophilic asthma

Asthma in the elderly is not as well studied as in younger age groups. Age-related immunosenescence may result in diminished TH2 inflammation, which raises a question about whether asthma in elderly patients responds well to anti-TH2 asthma biologics. We sought to determine whether asthma in elderly people has different TH2 biomarkers and clinical features compared to nonelderly people, and if disease in the 2 age groups responds differently to anti-TH2 biologics. We also aimed to identify treatment-responsive phenotypes with clinical and biomarker features that could be used to predict best response to biologics. A retrospective chart review was conducted for 56 patients (30 elderly [age ≥62 years] and 26 nonelderly [ages 18-59 years] subjects) with severe asthma treated with dupilumab or benralizumab. Differences in baseline characteristics and response to treatment were analyzed. Ahierarchical cluster analysis was also performed to identify treatment-responsive phenotypes. Significance threshold was P= .05 for all analyses. Baseline characteristics and TH2 biomarkers (blood eosinophil level, total IgE, aeroallergen sensitivity) were similar between elderly and nonelderly subjects. The disease in both groups responded well to biologics (improvement in ACT scores, decreased exacerbations, decreased need for prednisone), but no significant response difference was found based on age groups. Cluster analysis identified 3 phenotypes, as follows: cluster 1, youngest age, moderate eosinophil levels, lowest total IgE, few environmental allergies, and least response to biologics; cluster 2, intermediate age, lowest eosinophil level, highest IgE level, many environmental allergies, and an intermediate response to biologics; and cluster 3, oldest ages, highest eosinophil levels, high total IgE, few environmental allergies, and best response to biologics. These results confirm trends seen in another study utilizing cluster analyses showing that subjects with highest levels of IgE and eosinophils responded better to biologic treatment for asthma. Elderly people with asthma should be considered for biologic therapy no differently than younger people. There may be subgroups of patients with different biologic responses based on age, allergenicity, IgE, and eosinophil levels that could be used to predict treatment response.

An ecological study of the spatiotemporal dynamics and drivers of domestically acquired campylobacteriosis in Ireland, 2011-2018.

In 2021, Campylobacteriosis was the main gastrointestinal disease in the European Union since 2007 according to the European Centre for Disease Prevention and Control. In the Republic of Ireland, the incidence of the disease is particularly high with approximately 3,000 cases per annum, raising significant concerns for national health authorities with an expected increase in the number of cases in the light of climate change. The current study sought to assess the spatio-temporal patterns of campylobacteriosis in the Republic of Ireland using 20,391 cases from January 2011 to December 2018. An ensemble of spatial statistics techniques including seasonal decomposition, spatial clustering and space-time scanning, were used to elucidate the main individual and spatio-temporal characteristics of the disease in the country. Findings revealed that cases from the paediatric age group (i.e., under 5 years old) were more likely to occur in rural areas (aOR: 1.1.27, CI 95% 1.14-1.41) while cases from the intermediate age group (i.e., >5 & <65 years old) were associated with urban living (aOR: 1.30, CI 95% 1.21-1.4). The disease exhibited a peak during Irish summer, with a stronger seasonal signal reported in counties located on the Western part of the country. Infection hotspots were more likely to occur in urban areas, and more particularly on the Southern part of the island and around the main metropolitan areas. Overall, research findings pointed out the influence of local and spatio-temporally specific socio-demographic and environmental risk factors (i.e., cooking habits, local weather, dietary types) therefore highlighting the need for initiating spatio-temporally targeted health management and surveillance strategies.

Scaling K2. VII. Evidence For a High Occurrence Rate of Hot Sub-Neptunes at Intermediate Ages

The NASA K2 mission obtained high-precision time-series photometry for four young clusters, including the near-twin 600–800 Myr old Praesepe and Hyades clusters. Hot sub-Neptunes are highly prone to mass-loss mechanisms, given their proximity to the host star and the weakly bound gaseous envelopes, and analyzing this population at young ages can provide strong constraints on planetary evolution models. Using our automated transit detection pipeline, we recover 15 planet candidates across the two clusters, including 10 previously confirmed planets. We find a hot sub-Neptune occurrence rate of 79%–107% for GKM stars in the Praesepe cluster. This is 2.5–3.5σ higher than the occurrence rate of % for the same planets orbiting the ∼3–9 Gyr old GKM field stars observed by K2, even after accounting for the slightly supersolar metallicity ([Fe/H] ∼ 0.2 dex) of the Praesepe cluster. We examine the effect of adding ∼100 targets from the Hyades cluster and extending the planet parameter space under examination, and we find similarly high occurrence rates in both cases. The high occurrence rate of young, hot sub-Neptunes could indicate either that these planets are undergoing atmospheric evolution as they age, or that planetary systems that formed when the Galaxy was much younger are substantially different than from today. Under the assumption of the atmospheric mass-loss scenario, a significantly higher occurrence rate of these planets at the intermediate ages of Praesepe and Hyades appears more consistent with the core-powered mass-loss scenario for the origin of the planet radius valley, compared to the photoevaporation scenario.

Vascular risk, gait, behavioral, and plasma indicators of VCID.

Cost-effective screening tools for vascular contributions to cognitive impairment and dementia (VCID) has significant implications. We evaluated non-imaging indicators of VCID using magnetic resonance imaging (MRI)-measured white matter (WM) damage and hypothesized that these indicators differ based on age. In 745 participants from the Mayo Clinic Study of Aging (≥50 years of age) with serial WM assessments from diffusion MRI and fluid-attenuated inversion recovery (FLAIR)-MRI, we examined associations between baseline non-imaging indicators (demographics, vascular risk factors [VRFs], gait, behavioral, plasma glial fibrillary acidic protein [GFAP], and plasma neurofilament light chain [NfL]) and WM damage across three age tertiles. VRFs and gait were associated with diffusion changes even in low age strata. All measures (VRFs, gait, behavioral, plasma GFAP, plasma NfL) were associated with white matter hyperintensities (WMHs) but mainly in intermediate and high age strata. Non-imaging indicators of VCID were related to WM damage and may aid in screening participants and assessing outcomes for VCID. Non-imaging indicators of VCID can aid in prediction of MRI-measured WM damage but their importance differed by age. Vascular risk and gait measures were associated with early VCID changes measured using diffusion MRI. Plasma markers explained variability in WMH across age strata. Most non-imaging measures explained variability in WMH and vascular WM scores in intermediate and older age groups. The framework developed here can be used to evaluate new non-imaging VCID indicators proposed in the future.

Dipping vigorous seedling roots in phosphorus-enriched slurry at transplanting efficiently increases lowland rice yields

P-dipping refers to the placement of phosphorus (P) fertilizer at the root system during transplanting of rice by adhering P-enriched slurry to the seedling roots. This approach is beneficial for smallholder farmers in sub-Saharan Africa who apply small amounts of P to highly P-fixing soils. This study aimed to identify the optimum seedling age for maximizing the impact of P-dipping. Pot experiments revealed that the adhered amounts of slurry to the roots with P-dipping increased in a sigmoidal pattern against seedling age. Correspondingly, the effect of P-dipping on the initial biomass was enlarged with older seedlings in a sigmoidal pattern, increasing slowly during the young seedling age (2.9–4.5 leaves), sharply during the intermediate seedling age (4.5–6.3 leaves), and plateauing during the old seedling age (6.3–7.0 leaves). Combining P-dipping with much older seedlings (> 7.0 leaves) resulted in severe transplanting shock and plant death. On-farm trials on 90 fields in Madagascar demonstrated a significant interaction between seedling age and P treatment on grain yield. The highest yield gains over the control from P-dipping were observed in seedlings with intermediate age (1.0 ​t ​ha−1), followed by old (0.7 ​t ​ha−1) and young (0.6 ​t ​ha−1) seedlings. These results suggested that vigorous and intermediate seedlings with higher slurry adherence than young seedlings and a lower risk of transplanting shock than old seedlings benefited most from P-dipping. This finding provides smallholder farmers with practical knowledge on how to apply the P-dipping more efficiently for achieving improved P management for sustainable rice production.

Determination of dynamical ages of open clusters through the A+ parameter – II

ABSTRACT Blue straggler stars (BSS), one of the most massive members of star clusters, have been used for over a decade to investigate mass segregation and estimate the dynamical ages of globular clusters (GCs) and open clusters (OCs). This work is an extension of our previous study, in which we investigated a correlation between theoretically estimated dynamical ages and the observed $A^+_{\mathrm{rh}}$ values, which represent the sedimentation level of BSS with respect to the reference population. Here, we use the ML-MOC algorithm on Gaia EDR3 data to extend this analysis to 23 OCs. Using cluster properties and identified members, we estimate their dynamical and physical parameters. In order to estimate the $A^+_{\mathrm{rh}}$ values, we use the main sequence and main sequence turnoff stars as the reference population. OCs are observed to exhibit a wide range of degrees of dynamical evolution, ranging from dynamically young to late stages of intermediate dynamical age. Hence, we classify OCs into three distinct dynamical stages based on their relationship to $A^+_{\mathrm{rh}}$ and Nrelax. NGC 2682 and King 2 are discovered to be the most evolved OCs, like Family III GCs, while Berkeley 18 is the least evolved OC. Melotte 66 and Berkeley 31 are peculiar OCs because none of their dynamical and physical parameters correlate with their BSS segregation levels.

Non-linear effects on the population performance of Bighead Carp under different maturation schedules

Bighead Carp currently threatens to invade the Laurentian Great Lakes from the Mississippi River, but the novel climatic conditions it will encounter by expanding northwards could affect its population performance. Bighead Carp in colder climates exhibits slower growth and matures later, with later maturation typically leading to larger adult size and increased fecundity and survival. Accordingly, the life-history strategies of Bighead Carp at its northern range limits could differ from those observed in its current invaded range. To explore how population performance could differ across changing environmental conditions, we used a stage- and age-based matrix population model parameterized with values reported for Bighead Carp populations around the world. The model was used to evaluate how different ages of maturity and their resulting impacts to body size, survival, and fecundity could impact rates of population growth and establishment. Age of maturity had a non-linear effect on population growth, with maturation at intermediate ages (4–6 years) resulting in better performance. However, performance differed less between maturation ages when fecundity was allowed to increase disproportionately with body size. Greater population growth at younger ages of maturity suggest that invasion at lower latitudes could enable establishment in fewer years due to faster rates of development in warmer temperatures. Across all maturation schedules, population growth was most sensitive to the recruitment of age-1 individuals and least sensitive to adult survival, and vital rates overall varied more in their contribution to population growth at younger ages of maturity. Thus, understanding the factors that control age-1 recruitment would inform projections of population performance for Bighead Carp in the Laurentian Great Lakes.

The evolution of the Milky Way’s thin disc radial metallicity gradient with K2 asteroseismic ages

ABSTRACT The radial metallicity distribution of the Milky Way’s disc is an important observational constraint for models of the formation and evolution of our Galaxy. It informs our understanding of the chemical enrichment of the Galactic disc and the dynamical processes therein, particularly radial migration. We investigate how the metallicity changes with guiding radius in the thin disc using a sample of red giant stars with robust astrometric, spectroscopic, and asteroseismic parameters. Our sample contains 668 stars with guiding radii 4 &amp;lt; Rg &amp;lt; 11 kpc and asteroseismic ages covering the whole history of the thin disc with precision ${\approx} 25 {{\, \rm per\ cent}}$. We use MCMC analysis to measure the gradient and its intrinsic spread in bins of age and construct a hierarchical Bayesian model to investigate the evolution of these parameters independently of the bins. We find a smooth evolution of the gradient from ≈−0.07 dex kpc−1 in the youngest stars to ≈−0.04 dex kpc−1 in stars older than 10 Gyr, with no break at intermediate ages. Our results are consistent with those based on asteroseismic ages from CoRoT, with that found in Cepheid variables for stars younger than 1 Gyr, and with open clusters for stars younger than 6 Gyr. For older stars we find a significantly lower metallicity in our sample than in the clusters, suggesting a survival bias favouring more metal-rich clusters. We also find that the chemical evolution model of Chiappini '09 is too metal poor in the early stages of disc formation. Our results provide strong new constraints for the growth and enrichment of the thin disc and radial migration, which will facilitate new tests of model conditions and physics.

Using the Gaia Excess Uncertainty as a Proxy for Stellar Variability and Age

Stars are known to be more active when they are young, resulting in a strong correlation between age and photometric variability. The amplitude variation between stars of a given age is large, but the age–variability relation becomes strong over large groups of stars. We explore this relation using the excess photometric uncertainty in Gaia photometry (VarG, VarBP, and VarRP) as a proxy for variability. The metrics follow a Skumanich-like relation, scaling as ≃t −0.4. By calibrating against a set of associations with known ages, we show how the Var of population members can predict group ages within 10%–20% for associations younger than ≃2.5 Gyr. In practice, age uncertainties are larger, primarily due to the finite group size. The index is most useful at the youngest ages (<100 Myr), where the uncertainties are comparable to or better than those derived from a color–magnitude diagram (CMD). The index is also widely available, easy to calculate, and can be used at intermediate ages where there are few or no pre- or post-main-sequence stars. We further show how Var can be used to find new associations and test if a group of comoving stars is a real coeval population. We apply our methods to Theia groups within 350 pc and find ≳90% are inconsistent with drawing stars from the field and ≃80% have variability ages consistent with those derived from the CMD. Our findings suggest the great majority of these groups contain real populations.

Faktor determinan kematian ibu di Kabupaten Sintang periode Agustus 2021 – 2022

Background: indicators of maternal health in a country can be seen through the high and low Maternal Mortality Rate (MMR). Sintang District in 2021 will be the second highest contributor to MMR in West Kalimantan Province. The determinants of maternal mortality are inconclusive and show different results in each region according to the method of collecting maternal mortality data.Objectives: the general objective of this research is to find out the Determinant Factors for Maternal Mortality in Sintang District for the period August 2021 – August 2022.Methods: using a mix of quantitative and qualitative methods with sequential explanatory. Quantitative research samples totaled 16 cases and qualitative informants amounted to 40 informants with indepth interview method. .Results: quantitative proxy determinant of maternal death caused by complications of childbirth (37.5%) 6 cases, determinant intermediate age &gt; 35 years (68.75%) 11 cases and ANC examination (68.75%) 11 cases, contextual determinant geographical area (75%) 12 cases. The qualitative results of the proxy determinants of maternal death were cases of retained placenta bleeding, the determinant intermediate the risk factors for maternal age &gt; 35 years, high maternal parity ≥ 3 times giving birth and incomplete ANC examinations &lt; 6 times. The determinant is far because it is in a rural area.Conclusion: the causes of maternal death in Sintang district are very complex and multifactor. Assistance for high-risk pregnant women by health personnel and monitoring periodic evaluations of the Program Birth Planning and Complication Prevention (P4K) must be carried out to reduce MMR in Sintang District.

Functional Outcome of Pediatric Subtrochanteric Fractures Treated With a Titanium Elastic Nailing System (TENS) Versus Plating.

Introduction Uncertainty exists regarding the ideal course of therapy for subtrochanteric fractures in children of intermediate age. These fractures arechallenging to treat, with scarce literature-based evidence to support a definitive implant. The ideal course of treatment should consider the patient's weight, age, femoral canal size, associated injuries, fracture stability, and surgeon's experience. A subtrochanteric femoral fracture in a child between the age of 5-12 is difficult to treat. For these patients, there is debate concerning the optimal internal fixation, hence this study was conducted to try and determine the superior mode of treatment for these fractures. The objective of this study is to compare functional outcomes of subtrochanteric fractures in the paediatric age group operated on with titanium elastic nail and plate fixation and the complications associated with both treatment modalities. Materials and methods Thisis a retrospective observational study of 40 cases that were admitted and operated on in the hospital of the current study from May 2007 to November 2021. Twenty patients underwent titanium elastic nailing system (TENS)nailing and the other 20 patients underwent plating for subtrochanteric fractures. The surgeries were conducted at our institute and patients were followed up at one-, three-, and six-month intervals. The final functional results were calculated with the help of the Flynn scoring system. Results Out of 40 patients involved in the present study, 17 were female while 23 were male. Twenty patients received treatment with titanium elastic nails, and the remaining twenty received plating. The majority of the patients were males around 9.6 years of age on average in the plating group and 8.9 years in the nailing group. In comparison to 75% of participants in the plating group, 40% of patients who received nailing showed excellent results. Results were satisfactory for five patients who received titanium elastic nails and one who received plating. The only poor outcomes were noticed in six people (30%) in TENS and three people (15%) in the plating group who went through unplanned surgery for complications. In comparison to the plating group, the overall rate of complication was much greater in the TENS group. Conclusion We would like to conclude our study that, in accordance with Flynn's score, both elastic nailing and plating stabilization can produce positive functional outcomes. Both groups have a similar percentage of excellent and good results.We also conclude that the overall complication rate is slightly higher for patients treated with TENSwhen compared to plating for subtrochanteric fractures.

Praecarbo strigoniensis, a new genus and species of Cormorants (Phalacrocoracinae) from the Late Oligocene of Hungary

Abstract The authors describe a fossil avian distal tibiotarsal epiphysis, remains of a cormorant (Phalacrociracinae), differing in age and morphological characters from other fossil cormorants. The fossil material comes from sandy marine deposits from the village of Máriahalom in north-western Hungary, together with the remains of 26 other vertebrate species, mostly marine. The age of the fossiliferous deposit is established in the Late Oligocene, at the beginning of the Chattian stage (MP25–30). The earliest fossil specimens of the subfamily Phalacrocoracinae are known from the Early-Middle Oligocene of North America and Northeast Africa, respectively. The rest of the known specimens are dated to the Late-Upper Oligocene and Lower Miocene. Thus, the fossil described here represents an intermediate age and it is less specialised in morphological characteristics. A new genus and species of cormorants, Praecarbo strigoniensisis described here based on the distal epiphysis of a fossil tibiotarsus.

Environment, subsistence strategies and settlement seasonality in the Negev Highlands (Israel) during the Bronze and Iron Ages: The palynological evidence.

The Negev Highlands arid region (southern Levant) shows evidence of sharp settlement fluctuations, with several periods of strong human activity separated by centuries with no evidence of sedentary life. In this study, we used the palynological method in order to shed light on the region's demographic history in the Bronze and Iron Ages. Fifty-four samples of pollen were collected and analyzed from secure archaeological contexts in four Negev Highlands sites: Nahal Boqer 66, dated to the Early Bronze Age and Early Intermediate Bronze Age (ca. 3200-2200 BCE); Ein Ziq, dated to the Early Intermediate Bronze Age (ca. 2500-2200 BCE); Mashabe Sade, dated to the Intermediate Bronze Age (ca. 2500-2000 BCE); and Haroa, dated to the Iron Age IIA (ca. late 10th through 9th centuries BCE). Our study revealed no evidence of cereal cultivation, with some hints that the inhabitants' diets may have included plants gathered from the wild. Only one of the sites, Nahal Boqer 66, showed micro-indicators of animal dung remains, suggesting that the inhabitants herded animals. The palynological evidence did, however, emphasize that the livestock there were not fed or supplemented with agricultural by-products but rather grazed freely on wild vegetation. The pollen data also suggest that all four sites were occupied only during late winter and spring. The activity in the Negev Highlands during the third millennium BCE was probably related to the copper industry in the Arabah and to copper transportation to settled neighboring lands, especially Egypt. A relatively humid climate supported the trade through the Negev Highlands. Deterioration in both climate conditions and settlement activity was documented in the second half of the Intermediate Bronze Age.

Lipofuscin, amyloids, and lipid peroxidation as potential markers of aging in Daphnia.

Accumulation of autofluorescent waste products, amyloids, and products of lipid peroxidation (LPO) are important hallmarks of aging. Until now, these processes have not been documented in Daphnia, a convenient model organism for longevity and senescence studies. We conducted a longitudinal cohort study of autofluorescence and Congo Red (CR) fluorescent staining for amyloids in four clones of D. magna. Additionally, we used a single time point cross-sectional common garden experiment within a single clone in which autofluorescence and BODIPY C11 fluorescence were measured. We observed a robust increase in autofluorescent spots that show diagnostic co-staining by Sudan Black indicating lipofuscin aggregates, particularly in the upper body region. There was also a significant clone-by-age interaction indicating that some genotypes accumulated lipofuscins faster than others. Contrary to predictions, CR fluorescence and lipid peroxidation did not consistently increase with age. CR fluorescence demonstrated a slight non-monotonous relationship with age, achieving the highest values at intermediate ages, possibly due to elimination of physiological heterogeneity in our genetically uniform cohorts. LPO demonstrated a significant ovary status-by-age interaction, decreasing with age when measured in Daphnia with full ovaries (late phase ovarian cycle) and showing no significant trend or slight increase with age when measured during the early phase in the ovarian cycle.

Leaf litter decomposition rates: influence of successional age, topography and microenvironment on six dominant tree species in a tropical dry forest

Litter decomposition is a central process in forest ecosystems because of its role in carbon and nutrient cycling and maintaining soil fertility. Decomposition is affected by plant traits, soil and microenvironmental conditions, topography, and vegetation structure, which varies with successional age. However, it is unclear how all these factors affect leaf decomposition of dominant tree species in tropical dry forests (TDFs). The objective of this study was to compare the decomposition rates of six dominant tree species: three legumes (Caesalpinia gaumeri,Lysiloma latisiliquum,Piscidia piscipula) and three non-legumes (Bursera simaruba,Gymnopodium floribundum,Neomillspaughia emarginata) in five successional age categories (8–10, 15–22, 23–30, 65–84, &amp;gt; 85 years-old) and two topographic conditions (flat and sloping sites) in a TDF, and to analyze the association with leaf traits (toughness, N, C and total phenols content) soil properties (bulk density, organic carbon, pH, clay), microenvironmental (litter and soil moisture, leaf area index), and vegetation variables (basal area, aboveground biomass, tree diameter, tree height). Litterbags were placed in 30–400 m2circular plots distributed in forests of the Yucatan, Mexico, and collected on six occasions spread over 230 days (540 samples per species).L. latisiliquumandC. gaumerihad the highest decomposition rates (as well as leaf nitrogen concentration and the lowest leaf toughness). Conversely,G. floribundumhad the lowest decay rate. Decomposition rate reached high values at intermediate successional ages, suggesting that soil fertility recovers rapidly after disturbance, although onlyL. latisiliquumshowed significant differences among stand age categories. Decomposition rate was consistently higher at flat sites than on slopes but the difference was significant only forL. latisiliquum. The soil, vegetation structure and microenvironmental variables that contributed most to explaining variation in decay rates varied among species. Decomposition tended to increase with soil moisture and clay content, and to decrease with soil organic carbon and pH suggesting susceptibility to climate change and soil erosion, particularly in sloping areas. Our results highlight the importance of analyzing species-specific responses, especially for dominant species, which likely contribute most to leaf litter decomposition, and to consider key ecological factors that influence this key process.

Effects of feedback on galaxies in the VELA simulations: elongation, clumps, and compaction

ABSTRACT The evolution of star-forming galaxies at high redshifts is very sensitive to the strength and nature of stellar feedback. Using two sets of cosmological, zoom-in simulations from the VELA suite, we compare the effects of two different models of feedback: with and without kinetic feedback from the expansion of supernovae shells and stellar winds. At a fixed halo mass and redshift, the stellar mass is reduced by a factor of ∼1–3 in the models with stronger feedback, so the stellar mass–halo mass relation is in better agreement with abundance matching results. On the other hand, the three-dimensional shape of low-mass galaxies is elongated along a major axis in both models. At a fixed stellar mass, M* &amp;lt; 1010 M⊙, galaxies are more elongated in the strong-feedback case. More massive, star-forming discs with high surface densities form giant clumps. However, the population of round, compact, old (agec &amp;gt; 300 Myr), quenched, stellar (or gas-poor) clumps is absent in the model with strong feedback. On the other hand, giant star-forming clumps with intermediate ages (agec = 100–300 Myr) can survive for several disc dynamical times, independently of feedback strength. The evolution through compaction followed by quenching in the plane of central surface density and specific star formation rate is similar under the two feedback models.

Aboveground live tree carbon stock and change in forests of conterminous United States: influence of stand age

BackgroundSequestration of carbon on forest land is a common and practical component within many climate action plans developed by state or municipal governments. Initial planning often identifies the general magnitude of sequestration expected given the scope of the project. Because age plays a key role in forest carbon dynamics, we summarize both the carbon stock and accumulation rates in live trees by age class and region, allowing managers and policymakers to assess the influence of forest age class structure on forest carbon storage as represented in current inventories. State-level information is provided in supplementary tables.ResultsAverage regional aboveground live tree carbon stocks (represented on a per area basis) range from 11.6 tC/ha in the Great Plains to 130 tC/ha in the Pacific Northwest West (west-side of Cascades) and increase with age in all regions, although in three regions carbon stock declined in the oldest age class. Regional average annual net change in live aboveground tree carbon varies from a low of − 0.18 tC /ha/yr in the Rocky Mountain South region to a high value of 1.74 tC/ha/yr in Pacific Northwest West. In all regions except Rocky Mountain South, accumulation rates are highest in the younger age classes and decline with age, with older age classes in several western regions showing negative rates. In the Southeast and Pacific Northwest West, intermediate age classes exhibit lower rates, likely due to harvesting activity.ConclusionsAboveground live tree carbon stocks increase and rates of average change decrease with age with few exceptions; this pattern holds when examining hardwood and softwood types individually. Because multiple forest management objectives are often considered and tradeoffs need to be assessed, we recommend considering both measures—standing stock and average annual change—of carbon storage. The relative importance of each component depends on management and policy objectives and the time frame related to those objectives. Harvesting and natural disturbance also affect forest carbon stock and change and may need to be considered if developing projections of potential carbon storage. We present forest carbon summaries at a scale and scope to meet information needs of managers and policymakers.