129 research outputs found
Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory
The combined fit of the measured energy spectrum and shower maximum depth distributions of ultra-high-energy cosmic rays is known to constrain the parameters of astrophysical models with homogeneous source distributions. Studies of the distribution of the cosmic-ray arrival directions show a better agreement with models in which a fraction of the flux is non-isotropic and associated with the nearby radio galaxy Centaurus A or with catalogs such as that of starburst galaxies. Here, we present a novel combination of both analyses by a simultaneous fit of arrival directions, energy spectrum, and composition data measured at the Pierre Auger Observatory. The model takes into account a rigidity-dependent magnetic field blurring and an energy-dependent evolution of the catalog contribution shaped by interactions during propagation. We find that a model containing a flux contribution from the starburst galaxy catalog of around 20% at 40 EeV with a magnetic field blurring of around 20° for a rigidity of 10 EV provides a fair simultaneous description of all three observables. The starburst galaxy model is favored with a significance of 4.5σ (considering experimental systematic effects) compared to a reference model with only homogeneously distributed background sources. By investigating a scenario with Centaurus A as a single source in combination with the homogeneous background, we confirm that this region of the sky provides the dominant contribution to the observed anisotropy signal. Models containing a catalog of jetted active galactic nuclei whose flux scales with the γ-ray emission are, however, disfavored as they cannot adequately describe the measured arrival directions
Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field
Search for pair-produced resonances decaying to quark pairs in proton-proton collisions at root s=13 TeV
A general search for the pair production of resonances, each decaying to two quarks, is reported. The search is conducted separately for heavier resonances (masses above 400 GeV), where each of the four final-state quarks generates a hadronic jet resulting in a four-jet signature, and for lighter resonances (masses between 80 and 400 GeV), where the pair of quarks from each resonance is collimated and reconstructed as a single jet resulting in a two-jet signature. In addition, a b-tagged selection is applied to target resonances with a bottom quark in the final state. The analysis uses data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 35.9 fb(-1), from proton-proton collisions at a center-of-mass energy of 13 TeV. The mass spectra are analyzed for the presence of new resonances, and are found to be consistent with standard model expectations. The results are interpreted in the framework of R-parity-violating supersymmetry assuming the pair production of scalar top quarks decaying via the hadronic coupling lambda ''(312) or lambda ''(323) and upper limits on the cross section as a function of the top squark mass are set. These results probe a wider range of masses than previously explored at the LHC, and extend the top squark mass limits in the (t) over tilde -> qq' scenario.Peer reviewe
Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults
Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We
estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from
1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories.
Methods We used data from 3663 population-based studies with 222 million participants that measured height and
weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate
trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children
and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the
individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For schoolaged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference)
and obesity (BMI >2 SD above the median).
Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in
11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed
changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and
140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of
underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and
countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior
probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse
was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of
thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a
posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%)
with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and
obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for
both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such
as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged
children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls
in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and
42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents,
the increases in double burden were driven by increases in obesity, and decreases in double burden by declining
underweight or thinness.
Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an
increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy
nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of
underweight while curbing and reversing the increase in obesit
Kringloopwijzer Akkerbouw : rekenmodel versie ‘april 2018’
De KringloopWijzer Akkerbouw is een rekeninstrument voor gebruik op PC’s dat op basis van ingevoerde bedrijfsgegevens van, onder meer, de bouwplansamenstelling en (kunst)mestgiften, een schatting maakt van de tekorten dan wel overschotten van stikstof, fosfaat en organische stof en de emissies die daarmee verbonden zijn. Om die schatting te kunnen maken, kan de KringloopWijzer gebruik maken van gedocumenteerde opbrengstgegevens en forfaitaire nutriëntengehaltes of, naar wens, de afvoer van nutriënten schatten op basis van de omvang, aard en methode van bemesting. Dit rapport beschrijft de aanleiding voor het ontwikkelen van de KringloopWijzer, de opbouw van de invoer- en uitvoerschermen en de achterliggende rekenregels tussen die beide. Het rapport eindigt met een inventarisatie van denkbare verbeterpunten en schetst op welke wijze de KringloopWijzer in de praktijk stap voor stap getest kan worden
Insights into the Chemical Nature and Formation Mechanisms of Discharge Products in Na–O<sub>2</sub> Batteries by Means of <i>Operando</i> X‑ray Diffraction
The chemical nature of discharge
products in nonaqueous Na–O<sub>2</sub> batteries attracts
attention due to the differing electrochemical
behavior of seemingly similar battery cells forming either sodium
peroxide (Na<sub>2</sub>O<sub>2</sub>) or sodium superoxide (NaO<sub>2</sub>). The experimental control parameters for the exclusive formation
of one or the other phase during discharge are still unknown. In this
paper, the important role of gas phase moisture on the chemical nature
of these products is demonstrated by means of <i>operando</i> XRD. <i>Operando</i> XRD is rarely reported for alkali-O<sub>2</sub> systems but provides valuable real time information about
the solid discharge products, growth/decomposition rates, and side
reactions in the cell. In addition, the discharge/charge mechanisms
of Na<sub>2</sub>O<sub>2</sub>·2H<sub>2</sub>O are monitored
in detail evidencing important differences from the cell reactions
forming NaO<sub>2</sub> and Li<sub>2</sub>O<sub>2</sub> and refuting
previous incorrect conclusions. Moreover, the effect of the applied
potential window during cycling is discussed, as it provides valuable
information for the future development of Na–O<sub>2</sub> batteries
as electrochemical energy stores
Metal Exposure and Sex Shape the Fatty Acid Profile of Midges and Reduce the Aquatic Subsidy to Terrestrial Food Webs
Aquatic micropollutants
can be transported to terrestrial
systems
and their consumers by emergent aquatic insects. However, micropollutants,
such as metals, may also affect the flux of physiologically important
polyunsaturated fatty acids (PUFAs). As certain PUFAs have been linked
to physiological fitness and breeding success of terrestrial consumers,
reduced fluxes from aquatic systems could affect terrestrial populations
and food webs. We chronically exposed larvae of the aquatic insect Chironomus riparius to a range of environmentally
relevant sediment contents of cadmium (Cd) or copper (Cu) in a 28-day
microcosm study. Since elevated water temperatures can enhance metals’
toxic effects, we used two temperature regimes, control and periodically
elevated temperatures (heat waves) reflecting an aspect of climate
change. Cd and Cu significantly reduced adult emergence by up to 95%
and 45%, respectively, while elevated temperatures had negligible
effects. Both metal contents were strongly reduced (∼90%) during
metamorphosis. Furthermore, the chironomid FA profile was significantly
altered during metamorphosis with the factors sex and metal exposure
being relevant predictors. Consequently, fluxes of physiologically
important PUFAs by emergent adults were reduced by up to ∼80%.
Our results suggest that considering fluxes of physiologically important
compounds, such as PUFAs, by emergent aquatic insects is important
to understand the implications of aquatic micropollutants on aquatic-terrestrial
meta-ecosystems
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