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According to the current concordance cosmological model, dark matter (DM) particles are collisionless and produce self-gravitating structures with a central cusp, which, generally, is not observed. The observed density tends to a central plateau or core, explained within the cosmological model through the gravitational feedback of baryons on DM. This mechanism becomes inefficient when decreasing the galaxy’s stellar mass so that in the low-mass regime (M ⋆ ≪ 106 M ⊙) the energy provided by the baryons is insufficient to modify cusps into cores. Thus, if cores exist in these galaxies they have to reflect departures from the collisionless nature of DM. Measuring the DM mass distribution in these faint galaxies is extremely challenging; however, their stellar mass distribution can be characterized through deep photometry. Here we provide a way of using only the stellar mass distribution to constrain the underlying DM distribution. The so-called Eddington inversion method allows us to discard pairs of stellar distributions and DM potentials requiring (unphysical) negative distribution functions in the phase space. In particular, cored stellar density profiles are incompatible with the Navarro–Frenk–White (NFW) potential expected from collisionless DM if the velocity distribution is isotropic and the system spherically symmetric. Through a case-by-case analysis, we are able to relax these assumptions to consider anisotropic velocity distributions and systems that do not have exact cores. In general, stellar distributions with radially biased orbits are difficult to reconcile with NFW-like potentials, and cores in the baryon distribution tend to require cores in the DM distribution.

We prepared 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized samples from never-dried Japanese cedar (JC) holocellulose, JC-callus, and bacterial cellulose (BC). The original never-dried samples and their TEMPO-oxidized products were characterized by neutral sugar composition analysis. TEMPO-oxidized cellulose nanofibrils (TEMPO-CNFs) were prepared from the TEMPO-oxidized samples by ultrasonication in water. The carboxy groups in TEMPO-CNFs were position-selectively esterified with 9-anthryl diazomethane (ADAM) to prepare TEMPO-CNF-COOCH2-C14H9 samples, which had UV absorption peak at 365 nm. The mass-average degree of polymerization (DPw) values of 1% lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) solutions of the original samples were determined by size-exclusion chromatography in combination with multi-angle laser-light scattering, ultraviolet absorption, and refractive index detection (SEC/MALLS/UV/RI), and were 5490, 2660, and 2380 for the JC holocellulose, JC-callus, and BC samples, respectively. The TEMPO-CNF-COOCH2-C14H9 sample solutions in 1% LiCl/DMAc were analyzed by SEC/MALLS/UV/RI to obtain SEC elution patterns. The patterns corresponded to the molar mass and carboxy group distributions of the samples, which were detected by RI and UV absorption of anthryl groups, respectively. The carboxy groups existed in the entire molar mass distribution regions of all the TEMPO-CNF samples, although their lower molar mass regions contained higher carboxy group densities. The obtained results indicate that random depolymerization occurred on the cellulose microfibril surfaces at the initial stage of TEMPO-catalyzed oxidation and/or ultrasonication in water. This depolymerization mechanism can explain all the obtained SEC-elution patterns of the TEMPO-CNFs, without considering the presence of periodically disordered regions in the cellulose microfibrils of the never-dried cellulose samples.

With mock strong gravitational lensing images, we investigate the performance of the broken power-law (BPL) model proposed by Du et al. (2020) on the mass reconstruction of galaxy-scale lenses. An end-to-end test is carried out, including the creation of mock strong lensing images, the subtraction of lens light, and the reconstruction of lensed images, where the lenses are selected from the galaxies in the Illustris-1 simulation. We notice that, regardless of the adopted mass models (the BPL model or its special cases), the Einstein radius can be robustly determined from imaging data alone, and the median bias is typically less than 1%. Away from the Einstein radius, the lens mass distribution tends to be harder to measure, especially at radii where there are no lensed images detected. We find that, with rigid priors, the BPL model can clearly outperform the single power-law models by achieving <5% median bias on the radial convergence profile within the Einstein radius. As for the source light reconstructions, they are found to be sensitive to both lens light contamination and lens mass models, where the BPL model with rigid priors still performs best when there is no lens light contamination. We show that, by correcting for the projection effect, the BPL model can estimate the aperture and luminosity weighted line-of-sight velocity dispersions to an accuracy of ∼6% scatter. These results highlight the great potential of the BPL model in strong lensing related studies.

Oxygen-minimum zones (OMZs) play an important role in the global oceanic nitrogen cycle because they account for 20 % to 40 % of the global loss of bioavailable nitrogen despite covering only about 1 % of the global ocean volume. The intermediate waters of the Bay of Bengal (BoB) host one of the most pronounced OMZs with near-anoxic conditions. However, it has not yet been recognized as a site with significant nitrate reduction. In this study, we examined the nitrogen-cycling processes in the East Equatorial Indian Ocean (EEIO) and the BoB by measuring water column properties, including temperature, salinity, oxygen, and nutrient concentrations, as well as nitrate isotope signatures, collected during the SO305 BIOCAT-IIOE2 cruise in April and May 2024. Potential temperature and salinity profiles showed distinct water masses and limited mixing between the BoB and the EEIO at 5° N. Nitrate stable isotope depth profiles varied significantly, driven by water mass distribution below 300 m and in situ fractionation above 300 m. Phytoplankton uptake acts as a nitrate sink in the surface waters, showing a significant isotopic enrichment and nitrogen deficit. In subsurface waters, nitrification was observed, primarily through regenerative production using previously assimilated biomass rather than newly fixed nitrogen from N2 fixation. Within the OMZ of the BoB, we identified a persistent nitrogen deficit and slightly enriched nitrate isotopes between 100 and 300 m, indicating nitrogen loss, which we attributed to anammox as the dominant nitrogen loss pathway in the BoB.

Background To investigate the effects of increased weight-loading on body weight, body composition, fat mass distribution, physical activity and energy balance in individuals with obesity. Methods This single-centre non-blinded randomised controlled trial was conducted from August 1, 2021, through February 28, 2022. Adults with obesity class 1 (body mass index, BMI 30–35 kg/m 2 ) were assigned to wear either a heavy (high load; 11% of body weight, n  = 28) or light (low load; 1% of body weight, n  = 30) weight vest for 8 h per day over 5 weeks. Results High-load treatment reduced fat mass (mean difference − 2.60%; 95% CI − 3.79, − 1.41) and increased lean mass (mean difference 1.40%; 95% CI 0.37, 2.42), with no significant effect on body weight. Fat mass reductions were primarily observed in weight-loaded regions but not in the non-weight-bearing regions such as the arms. Waist circumference decreased (mean difference − 2.26%; 95% CI − 3.81, − 0.71) in the high-load group compared to the low-load group. Despite these beneficial changes, sedentary time was higher in the high-load group (mean difference 4.69%; 95% CI 0.98, 8.39) compared to the low-load group, while energy expenditure and energy intake remained unchanged. Conclusions Increased weight-loading reduced fat mass and increased lean mass, resulting in a healthier body composition. These effects were achieved despite no increase in physical activity. The fat mass-reducing effect was primarily seen in weight-loaded regions, implying local adaptation to the increased loading. Trial registration Registered at ClinicalTrials.gov (NCT04697238) in 2021.

[Display omitted] •Model muscle strength personalized using maximum voluntary isometric contractions.•Model segmental mass personalized using dual-energy x-ray absorptiometry.•Personalization of biomechanical models affects simulation joint contact forces.•Changes in internal forces due to load carriage varied across the cohort. Military overuse injuries are associated with greater internal loads during load carriage and cause decreased readiness and increased costs. Low physical fitness, including low muscle strength, is a modifiable injury risk factor, making it an important focus for injury prevention. Evaluating potential injury mechanisms from biomechanical modeling and simulation may be useful, particularly for individuals who have unique muscle strengths and body segment mass distributions. However, modeled muscle strength from average adults is likely underestimated for trained, active-duty military personnel, which may influence internal load calculations. Thus, we evaluated the effects of muscle strength and segment mass distribution personalization on joint contact impulses and peak forces, and muscle force impulses from musculoskeletal simulations. Full-body kinematics, ground reaction forces, and electromyography were collected from 16 active-duty participants under two walking conditions: 1) no-pack and 2) pack (posteriorly added load, total 46 kg). These data drove and validated simulations of models with different types of personalization. Modeled segment masses were scaled using measured regional masses from dual-energy x-ray absorptiometry. Modeled muscle strengths were scaled from eight maximum voluntary isometric contractions measured using an instrumented dynamometer including the lumbar, hip, knee, and ankle. Personalized mass-distribution scaling had 6% greater lumbar joint contact impulses in walking compared to not personalized (p = .006). Personalized muscle strength scaling had greater joint contact impulses at the lumbar (42%), hip (25%), and knee (8%) (p < .001), and smaller impulses at the ankle (−4%) (p = .048) compared to not personalized. Results were similar for peak joint contact forces. Model personalization is beneficial to quantify internal loading and evaluate training interventions.

Interannual variability in the volumetric water mass distribution within the North Atlantic Subtropical Gyre is described in relation to variability in the Atlantic meridional overturning circulation. The relative roles of diabatic and adiabatic processes in the volume and heat budgets of the subtropical gyre are investigated by projecting data into temperature coordinates as volumes of water using an Argo-based climatology and an ocean state estimate (ECCO version 4). This highlights that variations in the subtropical gyre volume budget are predominantly set by transport divergence in the gyre. A strong correlation between the volume anomaly due to transport divergence and the variability of both thermocline depth and Ekman pumping over the gyre suggests that wind-driven heave drives transport anomalies at the gyre boundaries. This wind-driven heaving contributes significantly to variations in the heat content of the gyre, as do anomalies in the air–sea fluxes. The analysis presented suggests that wind forcing plays an important role in driving interannual variability in the Atlantic meridional overturning circulation and that this variability can be unraveled from spatially distributed hydrographic observations using the framework presented here.

Information on recent photosynthetic biomass distribution and biogeography of Arctic marine pico-eukaryotes (0.2-3 μm) is needed to better understand consequences of environmental change for Arctic marine ecosystems. We analysed pico-eukaryote biomass and community composition in Fram Strait and large parts of the Central Arctic Ocean (Nansen Basin, Amundsen Basin) using chlorophyll a (Chl a) measurements, automated ribosomal intergenic spacer analysis (ARISA) and 454-pyrosequencing. Samples were collected during summer 2012, the year with the most recent record sea ice minimum. Chl a concentrations were highest in eastern Fram Strait and pico-plankton accounted for 60-90% of Chl a biomass during the observation period. ARISA-patterns and 454-pyrosequencing revealed that pico-eukaryote distribution is closely related to water mass distribution in the euphotic zone of the Arctic Ocean. Phaeocystaceae, Micromonas sp., Dinophyceae and Syndiniales constitute a high proportion of sequence reads, while sequence abundance of autotrophic Phaeocystaceae and mixotrophic Micromonas sp. was inversely correlated. Highest sequence abundances of Phaeocystaceae were observed in the warm Atlantic Waters in Fram Strait, while Micromonas sp. dominated the abundant biosphere in the arctic halocline. Our results are of particular interest considering existing hypotheses that environmental conditions in Nansen Basin might become more similar to the current conditions in Fram Strait. We propose that in response, biodiversity and biomass of pico-eukaryotes in Nansen Basin could resemble those currently observed in Fram Strait in the future. This would significantly alter biogeochemical cycles in a large part of the Central Arctic Ocean.

The Southern Ocean plays a crucial role in the global carbon cycle, ocean heat transport, and Antarctic ice dynamics. Investigating past variability in the Southern Ocean, including temperature and water mass distribution, can improve understanding of how this system may respond to current climate change. Isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGTs) can be used as an ocean temperature proxy and have been applied to sediments in the Southern Ocean to reconstruct past temperature variability. However, applications of current isoGDGT-based temperature indices are subject to substantial uncertainty in the Antarctic Zone. In this study, we propose a new isoGDGT-based index, the Antarctic IsoGDGT Zonal (AIZ) index, composed of GDGT-0, GDGT-1 and GDGT-2, developed through statistical reanalysis of Southern Ocean core-top data. We interpret that the AIZ index captures shifts in archaeal community composition across the Polar Front (PF). South of the PF, cold-adapted archaea, which are characterized by high relative abundances of GDGT-0, dominate, whereas more diverse archaeal communities occur north of the PF. Because these community shifts are tied to water mass boundaries, the AIZ index serves as an effective tracer for reconstructing past PF movements. Furthermore, the AIZ  index exhibits a significant correlation with subsurface temperature (subST) south of the PF, suggesting that it can be used as a temperature proxy in the Antarctic Zone (subST=24.17×AIZ-1.45 (R2 = 0.81, n = 134, p < 0.0001)). Applying the AIZ index to late Pleistocene sediment cores collected around the ACC confirms its reliability as a water mass tracer and temperature proxy in the Antarctic Zone. Our study highlights the high potential of isoGDGTs for reconstructing palaeoceanographic conditions in the Southern Ocean.

Lignin, a major cell‐wall component of woody biomass, exhibits photoluminescent (PL) properties. Controlling the intensity and colour of the PL is essential for producing lignin‐based value‐added materials. Herein, we modify the PL properties of lignin via genetic engineering of novel luminophore structures. Feruloyl‐CoA 6′‐hydroxylase (F6′H1) is a 2‐oxoglutarate‐dependent dioxygenase that catalyses the conversion of feruloyl‐CoA, an intermediate of the biosynthesis pathway of monolignol, into 6′‐hydroxyferuloyl‐CoA, the precursor of scopoletin. To modify the lignin PL properties, the F6′H1 gene (F6′H1) from Arabidopsis thaliana is overexpressed in the hybrid aspen (Populus tremula × tremuloides T89), incorporating scopoletin into the lignin molecule. Cellulolytic enzyme lignin (CEL) was isolated from transgenic aspens with different overexpression levels of F6′H1 and evaluated for its PL properties. In N.N‐dimethylformamide solution, CEL from the F6′H1‐overexpressed aspen emitted clear PL with higher intensity and a longer wavelength than the wild‐type CEL. Size exclusion chromatography revealed a wide molar mass distribution of the chromophore. Interestingly, the PL of the CEL from the F6′H1 transgenic lines was limitedly quenched in low polar solvents and at high concentrations. The CEL from F6'H1 emitted obvious PL not only in solution but also in polymer film. Furthermore, the CEL of F6′H1 lines exhibited a reversible photodimerisation reaction characteristic of coumarins. These results suggest that genetic engineering can incorporate new luminophores such as scopoletin into lignin, thus producing value‐added materials.