Relative Importance Research Articles

Understanding earthquake location uncertainties using global sensitivity analysis framework

SUMMARY Earthquake hypocentres are routinely obtained by a common inversion problem of P- and S-phase arrivals observed on a seismological network. Improving our understanding of the uncertainties associated with the hypocentral parameters is crucial for reliable seismological analysis, understanding of tectonic processes and seismic hazard assessment. However, current methods often overlook uncertainties in velocity models and variable trade-offs during inversion. Here, we propose to unravel the effects of the main sources of uncertainty in the location process using techniques derived from the Global Sensitivity Analysis (GSA) framework. These techniques provide a quantification of the effects of selected variables on the variance of the earthquake location using an iterative model that challenges the inversion scheme. Specifically, we consider the main and combined effects of (1) variable network geometry, (2) the presence of errors in the analyst’s observations and (3) errors in velocity parameters from a 1-D velocity model. These multiple sources of uncertainty are described by a dozen of random variables in our model. Using a Monte Carlo sampling approach, we explore the model configurations and analyse the differences between the initial reference location and 100 000 resulting hypocentral locations. The GSA approach using Sobol's variance decomposition allows us to quantify the relative importance of our choice of variables. It highlights the critical importance of the velocity model approximation and provides a new objective and quantitative insight into understanding the sources of uncertainty in the inversion process.

Interactions of Low-Energy Muons with Silicon: Numerical Simulation of Negative Muon Capture and Prospects for Soft Errors

In this paper, the interactions of low-energy muons (E < 10 MeV) with natural silicon, the basic material of microelectronics, are studied by Geant4 and SRIM simulation. The study is circumscribed to muons susceptible to slowdown/stop in the target and able to transfer sufficient energy to the semiconductor to create single events in silicon devices or related circuits. The capture of negative muons by silicon atoms is of particular interest, as the resulting nucleus evaporation and its effects can be catastrophic in terms of the emission of secondary ionizing particles ranging from protons to aluminum ions. We investigate in detail these different nuclear capture reactions in silicon and quantitatively evaluate their relative importance in terms of number of products, energy, linear energy transfer, and range distributions, as well as in terms of charge creation in silicon. Finally, consequences in the domain of soft errors in microelectronics are discussed.

Decadal co‐variation of the aerosols over East Asia and the East Asian jet streams in the boreal winter

AbstractThe changes in the East Asian polar‐front jet (EAPJ) and the East Asian subtropical jet (EASJ) profoundly impact the weather and climate in East Asia. However, the link between aerosols and the jet streams is still unclear. Here, we investigated the decadal co‐variation of aerosols and the East Asian jet streams in the boreal winter during the period of 1980–2019. In synch with a positive change in aerosol optical depth over East Asia, 300‐hPa winds show an equatorward shift of the land branch of the EASJ, and weakened EAPJ and oceanic branch of the EASJ. This can be linked to the enhanced meridional temperature gradient along 30°–50° N but weakened in northern regions and the decreasing synoptic‐scale transient eddy kinetic energy over subtropical Pacific. Relative importance estimation of aerosols and ocean signals emphasized the contributions of aerosols in jet variations. In turn, meteorological conditions related to jet streams also contribute to variations in aerosols, the decadal co‐variations are a result of their interactions, particularly for the oceanic branch of EASJ. The findings would be helpful in providing potential indicators of climate change.

Exploring the Driving Forces of Vegetation Greening on the Loess Plateau at the County Scale

China has implemented several ecological projects in the Loess Plateau region to address severe land degradation and soil erosion. Accurately assessing ecological restoration and its driving factors remains challenging. Previous studies in this area concentrated on driving factors have mainly focused on natural factors at the regional or watershed scale, with limited consideration of socioeconomic factors at the county scale. In this study conducted in Huanglong County on the Loess Plateau, the focus was to fill the gaps in previous research and provide insights into the socioeconomic driving forces behind vegetation greening. Remote sensing image data (NDVI) from 1999 to 2019 were used to analyze vegetation greenness dynamics in the region. Five socioeconomic variables were considered, including afforestation intensity, deforestation intensity, agricultural intensity, village intensity, and road intensity layers, to characterize the impact of afforestation, agriculture, and urbanization policies. The RESTREND (residual trends) method was employed to assess the relative importance of climate and human activities on vegetation dynamics. This study found that temperature–NDVI relationships are more suitable for building RESTREND models than precipitation–NDVI relationships. Human activity was the main driver of vegetation dynamics, contributing 62% compared to 38% from climate change. Agricultural practices and afforestation were found to have a positive impact on ecological restoration, while deforestation and urbanization had no significant impact. These findings highlight a conceptual framework for understanding the intricate relationship between ecological restoration, climatic factors, and human activity on the Loess Plateau. This study suggests that significant progress has been made in ecological restoration through human efforts in combating land degradation. However, it emphasizes the need to strengthen natural conservation efforts and gradually transition toward restoration processes driven by natural forces for sustainable socioeconomic development. The methodology used in this study can be applied to explore the driving forces of ecological restoration in other regions facing human-driven land degradation.

Comparison of macrozoobenthic communities and environmental variables in the subtidal zones between a nearly closed bay and an open bay

To compare the impact of human activities and geographical environment on macrozoobenthic communities in bays, four season surveys of macrozoobenthos and environmental variables in Kaozhou Bay (a nearly closed bay) and Honghai Bay (an open bay) were conducted. CLUSTER, non-metric multi-dimensional scaling (NMDS) and the relative importance index (IRI) showed that the macrozoobenthic communities were different between Kaozhou Bay and Honghai Bay. The top three dominant species in Kaozhou Bay are brackish species, including Dendronereis pinnaticirris, Euclymene annandalei and Neanthes glandicincta, while the top three dominant species in Honghai Bay are hyperhaline species, including Paraprionospio pinnata, Amphioplus laevis and Aglaophamus dibranchis. Two-way Analysis of Variance (ANOVA) showed that the species number, Shannon-Wiener diversity index, evenness index, richness index, AMBI, M-AMBI, water depth, salinity, and dissolved oxygen in Kaozhou Bay were significantly lower than those in Honghai Bay, while the concentrations of total nitrogen, total phosphorus, silicate, and mercury in Kaozhou Bay were significantly higher than those in Honghai Bay. Principal components analysis (PCA) showed that Kaozhou Bay was associated with higher concentration of total nitrogen, total phosphorus, and silicate, and Honghai Bay was characterized by deeper water, higher salinity, and higher concentration of dissolved oxygen. BIO-ENV analysis showed that water depth was the most important environmental factor affecting macrozoobenthic community in two bays. The above results showed that the species diversity index and richness index of Kaozhou Bay were lower than those of Honghai Bay because of the geographical environment difference between the two bays.

On the potential use of highly oxygenated organic molecules (HOMs) as indicators for ozone formation sensitivity

Abstract. Ozone (O3), an important and ubiquitous trace gas, protects lives from harmful solar ultraviolet (UV) radiation in the stratosphere but is toxic to living organisms in the troposphere. Additionally, tropospheric O3 is a key oxidant and a source of other oxidants (e.g., OH and NO3 radicals) for various volatile organic compounds (VOCs). Recently, highly oxygenated organic molecules (HOMs) were identified as a new compound group formed from the oxidation of many VOCs, making up a significant source of secondary organic aerosol (SOA). The pathways forming HOMs from VOCs involve autoxidation of peroxy radicals (RO2), formed ubiquitously in many VOC oxidation reactions. The main sink for RO2 is bimolecular reactions with other radicals, such as HO2, NO, or other RO2, and this largely determines the structure of the end products. Organic nitrates form solely from RO2 + NO reactions, while accretion products (“dimers”) form solely from RO2 + RO2 reactions. The RO2 + NO reaction also converts NO into NO2, making it a net source for O3 through NO2 photolysis. There is a highly nonlinear relationship between O3, NOx, and VOCs. Understanding the O3 formation sensitivity to changes in VOCs and NOx is crucial for making optimal mitigation policies to control O3 concentrations. However, determining the specific O3 formation regimes (either VOC-limited or NOx-limited) remains challenging in diverse environmental conditions. In this work we assessed whether HOM measurements can function as a real-time indicator for the O3 formation sensitivity based on the hypothesis that HOM compositions can describe the relative importance of NO as a terminator for RO2. Given the fast formation and short lifetimes of low-volatility HOMs (timescale of minutes), they describe the instantaneous chemical regime of the atmosphere. In this work, we conducted a series of monoterpene oxidation experiments in our chamber while varying the concentrations of NOx and VOCs under different NO2 photolysis rates. We also measured the relative concentrations of HOMs of different types (dimers, nitrate-containing monomers, and non-nitrate monomers) and used ratios between these to estimate the O3 formation sensitivity. We find that for this simple system, the O3 sensitivity could be described very well based on the HOM measurements. Future work will focus on determining to what extent this approach can be applied in more complex atmospheric environments. Ambient measurements of HOMs have become increasingly common during the last decade, and therefore we expect that there are already a large number of groups with available data for testing this approach.

What matters most to people with metastatic uveal melanoma? A qualitative study to inform future measurement of health-related quality of life.

Metastatic uveal melanoma (mUM) is a rare cancer with poor prognosis, but novel treatments are emerging. Currently, there are no mUM-specific health-related quality of life (HRQL) questionnaires available for clinical research. We aimed to explore how mUM and its treatment affect HRQL and assess the content validity of existing questionnaires. Participants were patients with mUM and healthcare professionals involved in their care. Qualitative data were collected using semi-structured interviews and focus groups. Data collection and analysis used an integrative approach involving inductive questions/coding to elicit new concepts and deductive questions/coding based on domains of existing HRQL questionnaires. Initial interviews/focus groups focussed on HRQL questionnaires designed for patients with uveal melanoma or liver metastases. As new concepts were elicited, domains and items from other questionnaires were subsequently added. Seventeen patients and 16 clinicians participated. HRQL concerns assessed by uveal melanoma-specific questionnaires were largely resolved by the time of metastasis. The Functional Assessment of Cancer Therapy - Immunotherapy Module (FACT-ICM) adequately captured most immunotherapy-related side effects during initial treatment cycles. However, most patients emphasised emotional impacts over physical ones, focussing on the existential threat posed by disease amidst uncertainty about treatment accessibility and effectiveness. Patients were also concerned with treatment burden, including time commitment, travel, need for hospitalisation, and expenses. The relative importance of HRQL issues varied over time and across treatment modalities, with no single questionnaire being sufficient. Pending further development and psychometric testing, clinical researchers may need to take a modular approach to measuring the HRQL impacts of mUM.

Experimenting the influence of corncob ash on the mechanical strength of slag-based geopolymer concrete

Abstract The construction sector has been under growing public attention recently as one of the leading causes of climate change and its detrimental effects on local communities. In this regard, geopolymer concrete (GPC) has been proposed as a replacement for conventional concrete. Predicting the concrete’s strength before pouring is, therefore, quite useful. The mechanical strength of slag and corncob ash (SCA–GPC), a GPC made from slag and corncob ash, was predicted utilizing multi-expression programming (MEP). Modeling parameters’ relative importance was determined using sensitivity analysis. When estimating the compressive, flexural, and split tensile strengths of SCA–GPC with MEP, 0.95, 0.93, and 0.92 R 2-values were noted between the target and predicted results. The developed models were validated using statistical tests for error and efficiency. The sensitivity analysis revealed that within the mix proportions, the slag quantity (65%), curing age (25%), and fine aggregate (3.30%) quantity significantly influenced the mechanical strength of SCA–GPC. The MEP models result in distinct empirical equations for the strength characteristics of SCA–GPC, unlike Python-based models, which might aid industry and researchers worldwide in determining optimal mix design proportions, thus eliminating unneeded test repetitions in the laboratory.

Comparative evaluation of lateral flow assays to diagnose chronic Trypanosoma cruzi infection in Bolivia.

Bolivia has the highest incidence of Chagas disease (CD) worldwide. Caused by the parasite Trypanasoma cruzi, CD is generally a chronic condition. Diagnosis is logistically and financially challenging, requiring at least two different laboratory-based serological tests. Many CD cases are missed; in Bolivia it is estimated just 6% of individuals chronically infected with T. cruzi get diagnosed. Achieving control on the way to elimination of CD requires a radical simplification of the current CD testing pathways, to overcome the barriers to accessing CD treatment. We aimed to generate unbiased performance data of lateral flow assays (LFAs) for T. cruzi infection in Bolivia, to evaluate their usefulness for improving T. cruzi diagnosis rates in a precise and efficient manner. This retrospective, laboratory-based, diagnostic evaluation study sought to estimate the sensitivity/specificity of 10 commercially available LFAs for T. cruzi, using the current CD diagnostic algorithm employed in Bolivia as the reference test method. All tests were blinded at the study site and performed by three operators. In total, 470 serum samples were tested, including 221 and 249 characterized as CD-positive/-negative, respectively. The LFAs were scored according to their relative importance using a decision-tree-based algorithm, with the mean decrease in Gini index as the scoring metric. The estimates of sensitivities ranged from 62.2-97.7% (95% confidence interval (CI) lower bound 55.0-94.7%); for specificities the range was 78.6-100% (95% CI lower bound 72.0-97.5%); 5/10 and 6/10 tests had sensitivity >90% and specificity >95%, respectively. Four LFAs showed high values of both sensitivity (93-95%) and specificity (97-99%). The agreement between 6 LFAs and the reference tests was almost perfect (Kappa 0.83-0.94). Most LFAs evaluated thus showed performances comparable with current laboratory-based diagnostic methods.

An enhanced decision making model for industrial robotic selection using three factors: Positive, abstained, and negative grades of membership

Traditional packaging industries that lack automation often grapple with a spectrum of challenges that impede operational efficiency, productivity and overall competitiveness. To maintain quality and safety, the food industry must transition from manual to robotic packaging processes. The most suitable robot for executing such task is identified via a new hybrid fuzzy Stratified Multi-Attribute Decision-Making (S-MADM). This model comprises Fuzzy-PIvot Pairwise RElative Criteria Importance Assessment (F-PIPRECIA) and Stratified Network Mapping (SNM). The Hesitant T-Spherical Fuzzy (HT-SF) set effectively tackles the uncertainty associated with the selection process by introducing three factors, namely, positive, abstained, and negative grades of membership. A case study is presented to demonstrate the novel fusion model and determine the optimal food packaging robot. A total of twelve criteria are selected from the literature based on the decision-maker’s judgment. Among the seven industrial robots, the ”Delta robot” gained the highest ranking (71%), followed by the ”Scara robot” (56%), and the ”Multi-Axis Gantry” (49%). Delta robots, with spider-like limbs, can move gently and accurately at fast speeds, with heavy motors fixed on the frame, allowing for lightweight moving parts. The proposed SNM technique helps to enhance the effectiveness of these alternatives by analyzing the possible, inefficient, and highly influential states of the system. The sensitivity study confirms this analysis and the system’s durability while the comparative study verifies the effectiveness and feasibility of the proposed technique than existing MADM models. This paradigm enables company stakeholders to invest in an industrial robot that not only delivers better results but also efficiently overcome barriers associated with manual packaging procedures.

How to Make a Zaydi Iman


 
 
 This article examines the Zaydi doctrine of the imamate through an analysis of historical depictions of the 169/786 revolt of Ḥusayn b. ʿAlī at Fakhkh by three different authors: Aḥmad b. Sahl al-Rāzī (d. late third/ninth century), al-Nāṭiq Yaḥyā b. al-Ḥusayn (d. 424/1033), and ʿAlī b. Bilāl al-Āmulī (d. fifth/eleventh century). The classical model of the Zaydi imamate holds that a descendant of ʿAlī b. Abī Ṭālib (through either Ḥasan or Ḥusayn) with the proper qualities becomes Imam by summoning supporters (daʿwa), administering the oath of allegiance (bayʿa), and rising up in rebellion (khurūj) against a tyrant. This article investigates the relative importance of these components in historical accounts composed after the establishment of Zaydi political power in Yemen and the Caspian region. It argues that the emergence of dynastic rule may have lessened the importance of rebellion while elevating a candidate’s exemplary personal qualities and political skill. This change is potentially embedded in narrative differences between the three sources.
 
 

Enabling knowledge sharing in a production context in China

AbstractThere is limited research on the cultural influence on knowledge sharing in production contexts. In view of the gap in literature, this study draws on a multi‐criteria decision‐making approach, the analytic hierarchy process (AHP), to identify and rank different enabling factors of knowledge sharing in the workplace of a Chinese electronics plant on the basis of the relative importance ascribed to them by operators, leaders, and managers. The fieldwork research was conducted in a Chinese electronic plant, considering the judgment of 121 operators (blue‐collar workers), 56 production leaders, and 9 managers selected by convenience. The findings reinforce the understanding about the importance of integrating factors related to people, process, and knowledge to enable knowledge management in different cultural contexts, which may support managers' needs for lessons learned from other organizations in the areas of knowledge management, organizational learning, and process management.

Chronic Active Lesions and Larger Choroid Plexus Explain Cognition and Fatigue in Multiple Sclerosis.

Chronic inflammation may contribute to cognitive dysfunction and fatigue in patients with multiple sclerosis (MS). Paramagnetic rim lesions (PRLs) and choroid plexus (CP) enlargement have been proposed as markers of chronic inflammation in MS being associated with a more severe disease course. However, their relation with cognitive impairment and fatigue has not been fully explored yet. Here, we investigated the contribution of PRL number and volume and CP enlargement to cognitive impairment and fatigue in patients with MS. Brain 3T MRI, neurologic evaluation, and neuropsychological assessment, including the Brief Repeatable Battery of Neuropsychological Tests and Modified Fatigue Impact Scale, were obtained from 129 patients with MS and 73 age-matched and sex-matched healthy controls (HC). PRLs were identified on phase images of susceptibility-weighted imaging, whereas CP volume was quantified using a fully automatic method on brain three-dimensional T1-weighted and fluid-attenuated inversion recovery MRI sequences. Predictors of cognitive impairment and fatigue were identified using random forest. Thirty-six (27.9%) patients with MS were cognitively impaired, and 31/113 (27.4%) patients had fatigue. Fifty-nine (45.7%) patients with MS had ≥1 PRLs (median = 0, interquartile range = 0;2). Compared with HC, patients with MS showed significantly higher T2-hyperintense white matter lesion (WM) volume; lower normalized brain, thalamic, hippocampal, caudate, cortical, and WM volumes; and higher normalized CP volume (p from <0.001 to 0.040). The predictors of cognitive impairment (relative importance) (out-of-bag area under the curve [OOB-AUC] = 0.707) were normalized brain volume (100%), normalized caudate volume (89.1%), normalized CP volume (80.3%), normalized cortical volume (70.3%), number (67.3%) and volume (66.7%) of PRLs, and T2-hyperintense WM lesion volume (64.0%). Normalized CP volume was the only predictor of the presence of fatigue (OOB-AUC = 0.563). Chronic inflammation, with higher number and volume of PRLs and enlarged CP, may contribute to cognitive impairment in MS in addition to gray matter atrophy. The contribution of enlarged CP in explaining fatigue supports the relevance of immune-related processes in determining this manifestation independently of disease severity. PRLs and CP enlargement may contribute to the pathophysiology of cognitive impairment and fatigue in MS, and they may represent clinically relevant therapeutic targets to limit the impact of these clinical manifestations in MS.

Key Factors Determining Nightside Energetic Electron Losses Driven by Whistler‐Mode Waves

AbstractEnergetic electron losses by pitch‐angle scattering and precipitation to the atmosphere from the radiation belts are controlled, to a great extent, by resonant wave particle interactions with whistler‐mode waves. The efficacy of such precipitation is primarily modulated by wave intensity, although its relative importance, compared to other wave and plasma parameters, remains unclear. Precipitation spectra from the low‐altitude, polar‐orbiting ELFIN mission have previously been demonstrated to be consistent with energetic precipitation modeling derived from empirical models of field‐aligned wave power across a wide swath of local‐time sectors. However, such modeling could not explain the intense, relativistic electron precipitation observed on the nightside. Therefore, this study aims to additionally consider the contributions of three modifications—wave obliquity, frequency spectrum, and local plasma density—to explain this discrepancy on the nightside. By incorporating these effects into both test particle simulations and quasi‐linear diffusion modeling, we find that realistic implementations of each individual modification result in only slight changes to the electron precipitation spectrum. However, these modifications, when combined, enable more accurate modeling of ELFIN‐observed spectra. In particular, a significant reduction in plasma density enables lower frequency waves, oblique, or even quasi field‐aligned waves to resonate with near ∼1 MeV electrons closer to the equator. We demonstrate that the levels of modification required to accurately reproduce the nightside spectra of whistler‐mode wave‐driven relativistic electron precipitation match empirical expectations and should therefore be included in future radiation belt modeling.

Nitrogen addition affected the root competition in Cunninghamia lanceolata-Phoebe chekiangensis mixed plantation.

Little is known about below-ground competition in mixed-species plantations under increasing nitrogen (N) deposition. This study aims to determine the effects of N addition on root competition in coniferous and broad-leaved species mixed plantations. A pot experiment was conducted using the coniferous species Cunninghamia lanceolata and the broad-leaved species Phoebe chekiangensis planted in mixed plantations with different competition intensities under N addition (0 or 45 kg N ha-1 yr-1). Biomass allocation, root morphology, root growth level, and competitive ability were determined after five months of treatment. Our findings indicated that root interactions in mixed plantations did not influence biomass allocation in either C. lanceolata or P. chekiangensis but promoted growth in C. lanceolata when no N was added. However, N addition decreased biomass accumulation in both species in the mixed plantation and had a negative effect on the root growth of C. lanceolata due to intensified competition. Addition of N increased the relative importance of root predatory competition in P. chekiangensis, and increased the allelopathic competitive advantage in C. lanceolata. This suggests that N addition causes a shift in the root competitive strategy from tolerance to competition. Overall, these findings highlight the significant impact that the addition of N can have on plant interactions in mixed plantations. Our results provide implications for the mechanisms of root competition in response to increasing atmospheric N deposition in mixed plantations.

The Magnetic Field in the Colliding Filaments G202.3+2.5

We observe the magnetic field morphology toward a nearby star-forming filamentary cloud, G202.3+2.5, using James Clerk Maxwell Telescope/POL-2 850 μm thermal dust polarization observations with an angular resolution of 14.″4 (∼0.053 pc). The average magnetic field orientation is found to be perpendicular to the filaments, while showing different behaviors in the four subregions, suggesting various effects from the filaments’ collision in these subregions. With the kinematics obtained by the N2H+ observation by IRAM, we estimate the plane-of-sky magnetic field strength by two methods, the classical Davis–Chandrasekhar–Fermi (DCF) method and the angular dispersion function (ADF) method, giving B pos,dcf and B pos,adf of ∼90 and ∼53 μG. We study the relative importance between the gravity (G), magnetic field (B), and turbulence (T) in the four subregions, and find G > T > B, G ≥ T > B, G ∼ T > B, and T > G > B in the north tail, west trunk, south root, and east wing, respectively. In addition, we investigate the projection effects on the DCF and ADF methods, based on a similar simulation case, and find the 3D magnetic field strength may be underestimated by a factor of ∼3 if applying the widely used statistical B pos-to-B 3D factor when using the DCF or ADF methods, which may further underestimate/overestimate the related parameters.

Expectation versus reality: How crisis statement essentials are evaluated by Gen Z stakeholders and crisis communication practitioners

AbstractAt the onset of a crisis, an initial organizational statement sets the tone for subsequent discussion. While existing literature provides strategic guidance, it offers limited insight into the message‐level execution of such statements. This study synthesizes insights from literature and trade publications to complement strategic literature by proposing a practical set of ‘crisis essentials’ which practitioners can leverage in composing an initial crisis statement. Upon identification of these elements from scholarly and industry literature, two online surveys presenting a hypothetical crisis scenario are released to Gen Z stakeholders and crisis communication practitioners in the United States; respondents rate the relative importance of each element. Gen Z was selected as the stakeholder population of interest due to their high activity on social media, their role as the talent which will be entering the workforce and eventually leadership roles, and the more limited existing analysis of this segment. Comparative analysis is conducted, based on two online surveys among adult individuals from these two populations, to evaluate whether gaps exist in stakeholder expectations and practitioner approaches. Findings reveal: the proposed elements (e.g., statement of the crisis, attribution, expert quote; 11 in total) were of nonzero importance to both Gen Z stakeholder respondents and crisis communication practitioner respondents, essentials related to the assuring stakeholders (e.g., action steps) were rated more highly than informational essentials (e.g., timeline), and importance ratings across survey samples were generally consistent. Practitioners should consider each of these proposed essentials when developing communication materials, and that while stakeholders expect sufficient information to understand a crisis event, they ultimately care about what the crisis means for the future of the organization. This study, grounded in crisis communication theory, provides a relevant, practical contribution to the implementation of effective strategic crisis communication in situations concerning Gen Z stakeholders.

The Effect of Ultraviolet Photon Pumping of H2 in Dust-deficient Protoplanetary Disks

We perform radiation hydrodynamics simulations to study the structure and evolution of a photoevaporating protoplanetary disk. Ultraviolet and X-ray radiation from the host star heats the disk surface, where H2 pumping also operates efficiently. We run a set of simulations in which we varied the number of dust grains or the dust-to-gas mass ratio, which determines the relative importance between photoelectric heating and H2 pumping. We show that H2 pumping and X-ray heating contribute more strongly to the mass loss of the disk when the dust-to-gas mass ratio is D≤10−3 . The disk mass-loss rate decreases with a lower dust amount, but remains around 10−10−11 M ⊙yr−1. In these dust-deficient disks, H2 pumping enhances photoevaporation from the inner disk region and shapes the disk mass-loss profile. We thus argue that the late-stage disk evolution is affected by the ultraviolet H2 pumping effect. The mass-loss rates derived from our simulations can be used in the study of long-term disk evolution.

Bottom-up rather than top-down mechanisms determine mesocarnivore interactions in Norway.

Interactions among coexisting mesocarnivores can be influenced by different factors such as the presence of large carnivores, land-use, environmental productivity, or human disturbance. Disentangling the relative importance of bottom-up and top-down processes can be challenging, but it is important for biodiversity conservation and wildlife management. The aim of this study was to assess how the interactions among mesocarnivores (red fox Vulpes vulpes, badger Meles meles, and pine marten Martes martes) were affected by large carnivores (Eurasian lynx Lynx lynx and wolf Canis lupus), land cover variables (proportion of agricultural land and primary productivity), and human disturbance, as well as how these top-down and bottom-up mechanisms were influenced by season. We analyzed 3 years (2018-2020) of camera trapping observations from Norway and used structural equation models to assess hypothesized networks of causal relationships. Our results showed that land cover variables were more strongly associated with mesocarnivore detection rates than large carnivores in Norway. This might be caused by a combination of low density of large carnivores in an unproductive ecosystem with strong seasonality. Additionally, detection rates of all mesocarnivores showed positive associations among each other, which were stronger in winter. The prevalence of positive interactions among predators might indicate a tendency to use the same areas and resources combined with weak interference competition. Alternatively, it might indicate some kind of facilitative relationship among species. Human disturbance had contrasting effects for different species, benefiting the larger mesocarnivores (red fox and badger) probably through food subsidization, but negatively affecting apex predators (wolf and lynx) and smaller mesocarnivores (pine marten). In a human-dominated world, this highlights the importance of including anthropogenic influences in the study of species interactions.

Immune response in paper wasp workers: Task matters more than age

Workers of social hymenopterans (ants, bees and wasps) display specific tasks depending on whether they are younger or older. The relative importance of behavior and age in modulating immune function has seldom been addressed. We compared the strength of encapsulation-melanization immune response (hereafter melanotic encapsulation) in paper wasps displaying age polyethism or experimentally prevented from behavioral specialization. Foragers of Polybia paulista had higher melanotic encapsulation than guards, regardless of their age. Nevertheless, melanotic encapsulation decreased with age when wasps were prevented from behavioral specialization. Thus, in this species, worker melanotic encapsulation seems more sensitive to task than age. Foraging is considered one of the riskier behaviors in terms of pathogen exposure, so upregulating melanotic encapsulation in foragers can possibly improve both individual and colony-level resistance against infections.