Spatial Pressure Variations Research Articles

Disentangling the influence of reservoir abundance and pathogen shedding on zoonotic spillover of the Leptospira agent in urban informal settlements.

Rats are major reservoirs for pathogenic Leptospira, the bacteria causing leptospirosis, particularly in urban informal settlements. However, the impact of variation in rat abundance and pathogen shedding rates on spillover transmission to humans remains unclear. This study aimed to investigate how spatial variation in reservoir abundance and pathogen pressure affect Leptospira spillover transmission to humans in a Brazilian urban informal settlement. A longitudinal eco-epidemiological study was conducted from 2013 to 2014 to characterize the spatial distribution of rat abundance and Leptospira shedding rates in rats and determine the association with human infection risk in a cohort of 2,206 community residents. Tracking plates and live-trapping were used to measure rat abundance and quantify rat shedding status and load. In parallel, four sequential biannual serosurveys were used to identify human Leptospira infections. To evaluate the role of shedding on human risk, we built three statistical models for: (1) the relative abundance of rats, (2) the shedding rate by individual rats, and (3) human Leptospira infection, in which "total shedding", obtained by multiplying the predictions from those two models, was used as a risk factor. We found that Leptospira shedding was associated with older and sexually mature rats and varied spatially and temporally-higher at valley bottoms and with seasonal rainfall (December to March). The point estimate for "total shedding" by rat populations was positive, i.e., Leptospira infection risk increased with total shedding, but the association was not significant [odds ratio (OR) = 1.1; 95% confidence interval (CI): 0.9, 1.4]. This positive trend was mainly driven by rat abundance, rather than individual rat shedding (OR = 1.8; 95% CI: 0.6, 5.4 vs. OR = 1.0; 95% CI: 0.7, 1.4]. Infection risk was higher in areas with more vegetative land cover (OR = 2.4; 95% CI: 1.2, 4.8), and when floodwater entered the house (OR = 2.4; 95% CI: 1.6, 3.4). Our findings indicate that environmental and hydrological factors play a more significant role in Leptospira spillover than rat associated factors. Furthermore, we developed a novel approach combining several models to elucidate complex links between animal reservoir abundance, pathogen shedding and environmental factors on zoonotic spillover in humans that can be extended to other environmentally transmitted diseases.

Assessing Impacts of Atmospheric Conditions on Efficiency and Siting of Large-Scale Direct Air Capture Facilities.

The cost and efficiency of direct air capture (DAC) of carbon dioxide (CO2) will be decisive in determining whether this technology can play a large role in decarbonization. To probe the role of meteorological conditions on DAC we examine, at 1 × 1° resolution for the continental United States (U.S.), the impacts of temperature, humidity, atmospheric pressure, and CO2 concentration for a representative amine-based adsorption process. Spatial and temporal variations in atmospheric pressure and CO2 concentration lead to strong variations in the CO2 available in ambient air across the U.S. The specific DAC process that we examine is described by a process model that accounts for both temperature and humidity. A process that assumes the same operating choices at all locations in the continental U.S. shows strong variations in performance, with the most influential variables being the H2O gas phase volume fraction and temperature, both of which are negatively correlated with DAC productivity for the specific process that we consider. The process also shows a moderate positive correlation of ambient CO2 with productivity and recovery. We show that optimizing the DAC process at seven representative locations to reflect temporal and spatial variations in ambient conditions significantly improves the process performance and, more importantly, would lead to different choices in the sites for the best performance than models based on a single set of process conditions. Our work provides a framework for assessing spatial variations in DAC performance that could be applied to any DAC process and indicates that these variations will have important implications in optimizing and siting DAC facilities.

Plantar pressure gradient and pressure gradient angle are affected by inner pressure of air insole.

Clinically, air insoles may be applied to shoes to decrease plantar pressure gradient (PPG) and increase plantar gradient angle (PGA) to reduce foot ulcers. PPG and PGA may cause skin breakdown. The effects of different inner pressures of inflatable air insoles on dynamic PPG and PGA distributions are largely unknown in non-diabetics and people with diabetes. This study aimed to explore the impact of varying inner air insole pressures on PPG and PGA to establish early mitigation strategies for people at risk of foot ulcers. A repeated measures study design, including three air insoles (80mmHg, 160mmHg, and 240mmHg) and two walking durations (10 and 20min) for a total of six walking protocols, was tested on 13 healthy participants (height, 165.8 ± 8.4cm; age, 27.0 ± 7.3years; and weight, 56.0 ± 7.9kg, BMI: 20.3 ± 1.7kg/m^2) over three consecutive weeks. PPG, a measurement of the spatial variation in plantar pressure around the peak plantar pressure (PPP) and PGA, a variation in the gradient direction values at the three plantar regions, big toe (T1), first metatarsal head (M1), and second metatarsal head (M2), were calculated. This study indicated that PPG was lower at 80mmHg air insoles after 20min of walking in the M1 region (p = 0.010). The PGA in the M2 increased at an air insole of 80mmHg compared to 240mmHg (p = 0.015). Compared to 20min, the 10min walking duration at 240mmHg of air insole had the lowest PPG in the M1 (p = 0.015) and M2 (p = 0.034) regions. The 80mmHg air insole significantly lowered the PPG compared to a 160mmHg and 240mmHg air insole. Moreover, the 80mmHg air insole significantly decreased PPP and increased PGA compared to the 160mmHg and 240mmHg air insole. A shorter walking period (10min) significantly lowered PPG. The findings of this study suggest that people with a higher risk of foot ulcers should wear softer air insoles to have a lower PPG, as well as an increased PGA.

Asynchronous Holocene human population changes in north and south China as related to animal resource utilization

During the Holocene, rich Neolithic and Bronze cultures developed in the middle and lower reaches of Yellow River valley (north China) and Yangtze River valley (south China), making them the core areas of past human activities. Thus, it is important to reveal the process and driving mechanism of regional population change. Agriculture development has always been taken as the key driver of population changes, and current studies mainly focus on the role that cultivation played, however, it is still unclear if animal resource utilization also contributed to regional population changes. Here, the spatiotemporal changes of population and domestic animal utilization levels in north and south China from 10 to 2 ka BP have been reconstructed based on 27,935 archaeological sites and faunal remains data from 94 sites, respectively, and the change in potential wild animal resources has been simulated by the Minimum Terrestrial Resource Model (MTRM). The results show asynchronous changes of population occurred in north and south China during 10–2 ka BP, which were correlated with regional domestic and potential wild animal resource utilization. In north China, more significant population growth corresponded to a greater increase of domestic animal ratios and a sharp decline of potential wild animal resources after 8 ka BP. In south China, less significant population growth was accompanied by a slower increase of domestic animal ratios and stable variations of potential wild animal resources. This research suggests that different changes of potential wild animal resources in north and south China contributed to spatial variations in survival pressure, utilization level of domestic animals, and population growth, which was further determined by asynchronous changes of precipitation in the two regions. This study explains the impact of climate changes on population from a new perspective.

Genetic variation at innate and adaptive immune genes - contrasting patterns of differentiation and local adaptation in a wild gull.

Immunogenetic variation in natural vertebrate populations is expected to respond to spatial and temporal fluctuations in pathogen assemblages. While spatial heterogeneity in pathogen-driven selection enhances local immunogenetic adaptations and population divergence, different immune genes may yield contrasting responses to the environment. Here, we investigated population differentiation at the key pathogen recognition genes of the innate and adaptive immune system in a colonial bird species, the black-headed gull Chroicocephalus ridibundus. We assessed genetic variation at three toll-like receptor (TLR) genes (innate immunity) and the major histocompatibility complex (MHC) class I and II genes (adaptive immunity) in gulls from seven colonies scattered across Poland. As expected, we found much greater polymorphism at the MHC than TLRs. Population differentiation at the MHC class II, but not MHC-I, was significantly stronger than at neutral microsatellite loci, suggesting local adaptation. This could reflect spatial variation in the composition of extracellular parasite communities (e.g., helminths), possibly driven by sharp differences in habitat structure between colonies. Despite contrasting patterns of population differentiation, both MHC classes showed similar regimes of diversifying selection. Some significant population differentiation was also observed at TLRs, suggesting that innate immune receptors may respond to fine-scale spatial variation in pathogen pressure, although this pattern could have been enhanced by drift. Our results suggested that local adaptation at the pathogen recognition immune genes can be maintained at relatively small or moderate spatial scales in species with high dispersal potential and they highlighted the complexity of immunogenetic responses of animals to heterogeneous environments.

A novel hydro‐mechanical coupled multiphysics model for slurry penetration in sand with application to face stability analysis of shield tunnel

AbstractThe slurry penetration in tunnels driven by the slurry TBM in the highly permeable water‐bearing ground is a complicated multiphysics process, which significantly affects the stability of the excavation face but has not been fully modelled. This study establishes a novel hydro‐mechanical coupled multiphysics modelling approach for face stability analysis. Different from existing methods, the proposed one is able to quantify simultaneously the spatial and temporal variation of slurry concentration, viscosity, stagnation gradient, soil porosity and pore pressure, as well as the soil skeleton deformation induced by the transferred slurry pressure in two or three‐dimension. The spatial and temporal pressure transfer from slurry suspension to soil skeleton during slurry penetration can be obtained. The coupled formulations are implemented into a finite element package for initial and boundary value problems at the engineering scale and enhanced by the Petrov‐Galerkin weighted residual stabilisation technique. After being validated through the experimental slurry infiltration tests, it is applied to a field case analysis to predict the excess pore pressure in front of the tunnel face, which shows good agreement with the field measurement. The efficiency of the applied slurry pressure and the pressure transfer mechanism are thus verified. Comparative calculations about the influence of the pressure transfer model are presented to further improve the understanding of the pressure transfer mechanism. The proposed approach is also verified applicable to estimate the optimum slurry pressure.

CFD simulation of the hydrodynamics within an RVF module in laminar regime

The dynamic filtration module called Rotating and Vibrating Filtration (RVF) is a performant device for membrane fouling control and limiting the formation of cake layer. Indeed, it can generate strong shear stress at the membrane surface decoupled from the feeding flowrate. Moreover, the pressure fluctuation that takes place in the device is also beneficial to control membrane fouling. A CFD model has been validated in laminar regime from experimental measurements of velocity fields and pressure distribution inside the RVF. The boundary layer development at the walls were carefully studied to better explain the effects of the rotation speed and the viscosity on the spatial distribution and time variations of pressure and shear stress at the membrane surface. It appears that shear stress is more efficient than pressure to control membrane performances in laminar regime.

A liquid-free conducting ionoelastomer for 3D printable multifunctional self-healing electronic skin with tactile sensing capabilities.

Conductive elastomers with both softness and conductivity are widely used in the field of flexible electronics. Nonetheless, conductive elastomers typically exhibit prominent problems such as solvent volatilization and leakage, and poor mechanical and conductive properties, which limit their applications in electronic skin (e-skin). In this work, a liquid-free conductive ionogel (LFCIg) with excellent performance was fabricated by utilizing the innovative double network design approach based on a deep eutectic solvent (DES). The double-network LFCIg is cross-linked by dynamic non-covalent bonds, which exhibit excellent mechanical properties (2100% strain while sustaining a fracture strength of 1.23 MPa) and >90% self-healing efficiency, and a superb electrical conductivity of 23.3 mS m-1 and 3D printability. Moreover, the conductive elastomer based on LFCIg has been developed into a stretchable strain sensor that achieves accurate response recognition, classification, and identification of different robot gestures. More impressively, an e-skin with tactile sensing functions is produced by in situ 3D printing of sensor arrays on flexible electrodes to detect light weight objects and recognize the resulting spatial pressure variations. Collectively, the results demonstrate that the designed LFCIg has unparalleled advantages and presents wide application potential in flexible robotics, e-skin and physiological signal monitoring.

Status and distribution of wild turkeys in the United States in 2019

AbstractAfter increases following restoration efforts, the wild turkey (Meleagris gallopavo) population appeared to decline during the early 2000s in many areas of the species' range. The 2014 status assessment indicated that estimated population size, harvest, and hunter numbers had declined since at least 2009. Several studies concurrently detailed regional declines in productivity of wild turkey populations. During 2019, we continued to monitor status of wild turkey populations in the United States by surveying state agency biologists charged with overseeing wild turkey management programs. We asked biologists to provide estimates of population abundance and distribution within their state. We also requested that each biologist provide data on turkey hunter numbers and harvest for both spring and fall hunting seasons, if those data were available. Based on agency biologist responses, wild turkey population size declined by ~3% across states that contributed data to both the 2014 and 2019 status updates. However, during our 2019 survey, abundance data were unavailable for 12 states that reported estimates for the 2014 assessment. We estimated that the number of wild turkey hunters declined by 18% between the 2014 and 2019 assessments, but note the 2019 estimate was confounded by missing data from 8 states that provided data during 2014. Across all reporting states, fall and spring harvests decreased by 31 and 12%, respectively, between the 2014 and 2019 assessments. Despite widespread recognition that standardization of monitoring methods across states would facilitate more consistent inferences about wild turkey abundance, further progress towards regional or national standardization is needed. Furthermore, the approach of converting harvest data to a population estimate by dividing harvest estimates by a constant percentage of estimated take should be revisited to ensure accuracy, especially given known spatial and temporal variation in harvest pressure, hunting activity, and hunter behavior. We encourage continued development of improved techniques to estimate wild turkey abundance and distribution, and recommend that all states and provinces consider standardized methods to accurately monitor and report harvest and hunter effort.

Simplified CFD Model for Perforated Tile with Distorted Outflow

Most of the perforated tile flow CFD models in the literature so far assume the air velocity coming out of the tile openings (pores) is uniform. However, in typical applications, such as data centers and indoor environments, perforated tile or diffuser outflow can be highly non-uniform due to many reasons (e.g., spatial variation of plenum pressure or varying local tile geometrical patterns). For an ideal (uniform) tile flow velocity that has the same flow rate as the non-uniform tile flow velocity, the tile flow momentum of the latter will always be greater because momentum scales with velocity squared. To illustrate the effect of tile flow velocity distortion, two generic CFD cases (one with uniform velocity and the other with non-uniform velocity) with multiple openings model are presented here. Their CFD results are compared to the momentum source model results and validated against previously published data of an isolated tile flow measurement. The momentum source model is one of the simplest/most practical CFD models that uses a body-force value for correcting the momentum deficit between perforated and fully open areas. Initially, the momentum source model results show good agreement with results of the uniform velocity case only. Thus, due to velocity distortion (non-uniform velocity) in the tile flow, the CFD results presented in this paper show a potential reason to modify the body-force value in the momentum source model with an adjustment factor (C). Several values of C factor are numerically investigated for the present distorted tile flow CFD case, and the best match is found to be at C, equaling approximately 1.6.

PVD-Aided Consolidation with Spatial Variations in Soil Properties and Initial Excess Pore Pressure

PVD-Aided Consolidation with Spatial Variations in Soil Properties and Initial Excess Pore Pressure

The relationships between toad behaviour, antipredator defences, and spatial and sexual variation in predation pressure.

BackgroundAnimal behaviour is under strong selection. Selection on behaviour, however, might not act in isolation from other fitness-related traits. Since predators represent outstanding selective forces, animal behaviour could covary with antipredator defences, such that individuals better suited against predators could afford facing the costs of riskier behaviours. Moreover, not all individuals undergo equivalent degrees of predation pressure, which can vary across sexes or habitats. Individuals under lower predation pressure might also exhibit riskier behaviours.MethodsIn this work, I tested these hypotheses on natterjack toads (Epidalea calamita). Specifically, I gauged activity time, exploratory behaviour and boldness in standard laboratory conditions, and assessed whether they correlated with body size and antipredator strategies, namely sprint speed, parotoid gland area and parotoid gland colour contrast. Additionally, I compared these traits between sexes and individuals from an agrosystem and pine grove, since there is evidence that males and agrosystem individuals are subjected to greater predation pressure.ResultsSprint speed as well as parotoid gland contrast and size appeared unrelated to the behavioural traits studied. In turn, body mass was negatively related to activity time, boldness and exploration. This trend is consistent with the fact that larger toads could be more detectable to their predators, which are mostly gape unconstrained and could easily consume them. As predicted, females exhibited riskier behaviours. Nonetheless, agrosystem toads did not differ from pine grove toads in the behavioural traits measured, despite being under stronger predation pressure.

Wireless sensor networks for pharmaceutical lyophilization: Quantification of local gas pressure and temperature in primary drying

Wireless sensor networks have become prolific in a wide range of industrial processes and offer several key advantages over their wired counterparts in terms of positioning flexibility, modularity, interconnectivity, and data routing. We demonstrate their utility in pharmaceutical lyophilization by developing a series of wireless devices to measure spatial variations in gas pressure and temperature during primary drying. The influence of shelf temperature, chamber pressure, excipient concentration, and dryer configuration are explored for various representative cycles using a laboratory-scale pharmaceutical lyophilizer. Pressure and temperature variations across the shelf for these cases are shown to vary up to 1.2 Pa and 10 °C, respectively. Experimental measurements are supported by computational fluid dynamics simulations to reveal the mechanisms driving the vapor flow. The measurements and simulation data are then combined to estimate the shelf-wise sublimation rate in the inverse sense to within a deviation of 3% based on comparison with gravimetric data. We then apply the sublimation rate profile to obtain the vial heat transfer coefficient and product mass transfer resistance for a 5% w/v mannitol formulation. Finally, these parameters are applied to a one-dimensional quasi-steady heat transfer model to predict the evolution of the product temperature over the course of primary drying. Thermocouple measurements of product temperature are compared directly to the simulated data and demonstrate accuracy comparable to existing published one-dimensional models.

Spherical cavity expansion in porous rock considering plasticity and damage

AbstractIn rock engineering, damage evolution upon loading imposes significant impacts on the stiffness of rock mass and its deformation characteristics. In order to investigate the influence of both damage and plasticity on cavity expansion, a plastic damage solution is derived for undrained spherical cavity expansion in rock medium. For the consideration of plasticity‐damage, Modified Cam‐Clay (MCC) model is selected as the plasticity driver, a damage evolution criterion is adopted and coupled with MCC. The coupled damage MCC model is validated against experimental data in the literature. The proposed cavity expansion solution with the consideration of plasticity damage is verified through a classic solution in literature. The role of damage in undrained spherical cavity expansion is investigated by studying the spatial variations of effective stress, pore pressure and damage for cases with different stress ratios. Distribution of cavity expansion induced plastic and damage zones for cases with different stress ratios are also reproduced and discussed. Cavity expansion results show that, the damage zone should be considered for engineering application as the plastic zone is affected due to the damage evolution. In addition, the stability (e.g., radial stress) of rock mass is overestimated in classical solution without the consideration of damage zone.

Tropospheric Correction of Sentinel-1 Synthetic Aperture Radar Interferograms Using a High-Resolution Weather Model Validated by GNSS Measurements

Synthetic Aperture Radar Interferometry (InSAR) is a space geodetic technique used for mapping deformations of the Earth’s surface. It has been developed and used increasingly during the last thirty years to measure displacements produced by earthquakes, volcanic activity and other crustal deformations. A limiting factor to this technique is the effect of the troposphere, as spatial and temporal variations in temperature, pressure, and relative humidity introduce significant phase delays in the microwave imagery, thus “masking” surface displacements due to tectonic or other geophysical processes. The use of Numerical Weather Prediction (NWP) models as a tropospheric correction method in InSAR can tackle several of the problems faced with other correction techniques (such as timing, spatial coverage and data availability issues). High-resolution tropospheric modelling is particularly useful in the case of single interferograms, where the removal of the atmospheric phase screen (and especially the highly variable turbulent component) can reveal large-amplitude deformation signals (as in the case of an earthquake). In the western Gulf of Corinth, prominent topography makes the removal of both the stratified and turbulent atmospheric phase screens a challenging task. Here, we investigate the extent to which a high-resolution WRF 1-km re-analysis can produce detailed tropospheric delay maps of the required accuracy by coupling its output (in terms of Zenith Total Delay or ZTD) with the vertical delay component in GNSS measurements. The model is operated with varying physical parameterization in order to identify the best configuration, and validated with GNSS zenithal tropospheric delays, providing a benchmark of real atmospheric conditions. We correct sixteen Sentinel-1A interferograms with differential delay maps at the line-of-sight (LOS) produced by WRF re-analysis. In most cases, corrections lead to a decrease in the phase gradient, with average root-mean-square (RMS) and standard deviation (SD) reductions in the wrapped phase of 6.0% and 19.3%, respectively. Results suggest a high potential of the model to reproduce both the long-wavelength stratified atmospheric signal and the short-wave turbulent atmospheric component which are evident in the interferograms.

Controlling factors of seasonal and spatial variation of riverine CO2 partial pressure and its implication for riverine carbon flux

Global carbon cycle is closely related to the earth's energy budget, because CO2 plays an active role in the global climate change. The higher CO2 partial pressure (pCO2) in inland water in comparison with atmosphere, causing a CO2 evasion from water to the air. However, the relationship between CO2 evasion, riverine carbon export, and hydrochemistry in watershed has remained largely unknown. This study collected 84 river water samples in Jiulongjiang River, to further address this subject on a small watershed scale. Water temperature fluctuation, riverine photosynthesis, and acidic matter input could not account for the seasonal variation of pCO2 in Jiulongjiang River. The spatial shifts of pCO2 were derived from the mixing process between headwater and soil influx. The soil influx with high pCO2 compensated the CO2 lost from evasion and caused pCO2 in Jiulongjiang River higher than the atmospheric level. The seasonal variation of pCO2 was caused by the precipitation difference between the wet season and dry season. The addition of rainwater significantly decreased the riverine pCO2 and HCO3− concentration in the wet season. The CO2 evasion rate in Jiulongjiang River was clearly higher than that in most worldwide large rivers. The annual CO2 evasion flux in Jiulongjiang River Basin was estimated about 2.48 × 105 T C/year, which was higher than the riverine total carbon export. The CO2 evasion rate exhibited significantly positive relationship with water surface area, indicating that the global CO2 evasion flux may be roughly estimated based on the observed regression relationship. Overall, our study indicated that it still requires collaborative effects to investigate the carbon dynamics in river water, more estimations of CO2 outgassing flux from river water under different hydrologic and geologic conditions are necessary.

Role of hydro-mechanical coupling in excavation-induced damage propagation, fracture deformation and microseismicity evolution in naturally fractured rocks

We present a numerical study of spatio-temporal damage evolution and fracture displacements around underground excavation in fractured rock masses. We conduct a comparative analysis of this problem based on a mechanical (M) model by assuming an invariant pore pressure and a hydro-mechanical (HM) model by solving the coupling between the fluid and solid fields. In both models, an elasto-brittle constitutive law is employed to mimic the deformational and failure behavior of intact rocks, while a non-linear stress-displacement relationship is used to account for the normal compression and shear dislocation of natural fractures. In the HM model, we simulate excavation-induced transient groundwater flow in fractured porous rocks based on Darcy's law. The hydraulic and mechanical fields are linked based on the coupling mechanisms of poroelasticity (direct HM coupling) and stress-dependent material properties (indirect HM coupling). Many important HM phenomena such as stress perturbation, pore pressure fluctuation, damage evolution and fracture deformation are realistically captured in our simulation. We find that both direct and indirect couplings play important roles, and the excavation-induced disturbance in rock varies with the coupling degree characterized by the Biot coefficient. One interesting observation is that excavation-induced stress redistribution around the tunnel instantly causes perturbed pore pressure in low-permeability matrix, which gradually becomes dissipated during the post-excavation drainage. We also highlight the role of natural fractures in the tunnel inflow process and elucidate the consequences of spatial and temporal pressure variations. In addition, we analyze the microseismicity occurrence during and after the excavation to gain insights into excavation and drainage-induced responses in the fractured rock. The results of our simulation and analysis have important implications for underground excavation involved in many geoengineering applications such as civil infrastructure, nuclear waste repository and oil/gas/geothermal wellbore systems.

Remote Sensing Supported Sea Surface pCO2 Estimation and Variable Analysis in the Baltic Sea

Marginal seas are a dynamic and still to large extent uncertain component of the global carbon cycle. The large temporal and spatial variations of sea-surface partial pressure of carbon dioxide (pCO2) in these areas are driven by multiple complex mechanisms. In this study, we analyzed the variable importance for the sea surface pCO2 estimation in the Baltic Sea and derived monthly pCO2 maps for the marginal sea during the period of July 2002–October 2011. We used variables obtained from remote sensing images and numerical models. The random forest algorithm was employed to construct regression models for pCO2 estimation and produce the importance of different input variables. The study found that photosynthetically available radiation (PAR) was the most important variable for the pCO2 estimation across the entire Baltic Sea, followed by sea surface temperature (SST), absorption of colored dissolved organic matter (aCDOM), and mixed layer depth (MLD). Interestingly, Chlorophyll-a concentration (Chl-a) and the diffuse attenuation coefficient for downwelling irradiance at 490 nm (Kd_490nm) showed relatively low importance for the pCO2 estimation. This was mainly attributed to the high correlation of Chl-a and Kd_490nm to other pCO2-relevant variables (e.g., aCDOM), particularly in the summer months. In addition, the variables’ importance for pCO2 estimation varied between seasons and sub-basins. For example, the importance of aCDOM were large in the Gulf of Finland but marginal in other sub-basins. The model for pCO2 estimate in the entire Baltic Sea explained 63% of the variation and had a root of mean squared error (RMSE) of 47.8 µatm. The pCO2 maps derived with this model displayed realistic seasonal variations and spatial features of sea surface pCO2 in the Baltic Sea. The spatially and seasonally varying variables’ importance for the pCO2 estimation shed light on the heterogeneities in the biogeochemical and physical processes driving the carbon cycling in the Baltic Sea and can serve as an important basis for future pCO2 estimation in marginal seas using remote sensing techniques. The pCO2 maps derived in this study provided a robust benchmark for understanding the spatiotemporal patterns of CO2 air-sea exchange in the Baltic Sea.

Spatial variation in propagule pressure and establishment of zebra mussels (Dreissena polymorpha) within a subtropical reservoir

This work was funded in part by grants from the Oklahoma Department of Wildlife Conservation, through the Sport Fish Restoration Program, Grant F-61-R, and the National Science Foundation (Grant numbers NSF-IOS 1712936 and NSF DEB 1831061) to KDH, the University of Oklahoma Biological Station (through Graduate Research Fellowships to TCH and JEB) and the University of Oklahoma Department of Biology (through Adams Fellowships to TCH and JEB), the Graduate Student Senate at the University of Oklahoma (through a research grant to TCH), and by Sigma Xi through a grant in aid of research to TCH. Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.

Hunting quotas, selectivity and stochastic population dynamics challenge the management of wild reindeer

Wildlife managers adjust harvest quotas based on population changes and specific management goals, like controlling population size and demography or minimizing human-�wildlife interactions. However, establishing quotas that best meet these goals can be challenging due to e.g. population fluctuations, climate change, and bias or variation in harvest effort. High-Arctic Svalbard reindeer Rangifer tarandus platyrhynchus experience strong interannual variation in population size and demographic structure due to environmental stochasticity. Here, we analyzed the demographic and spatial bias of reindeer harvest in relation to quota regulations, hunter preferences, and population dynamics. Despite the protective management goal to avoid demographic impacts, 30 yr of data revealed that the harvest was consistently biased towards yearlings and male adults. This hunting selectivity resulted from both hunter preferences and the coarse license categories separating ‘calf’, ‘yearling or female adult’, and ‘free choice’ licenses. We developed Bayesian multinomial likelihood models to account for hunting selectivity and optimize annual quota distributions among license categories using population monitoring data. Optimized annual quota distributions varied strongly due to demographic fluctuations associated with strong climate variability, whereas simulated harvest offtakes showed that the protective management goal is inherently challenged by the coarse license categories. Although on average, only 7% of the hunted population was harvested annually, we found strong spatial variation in harvest pressure, with potential implications for spatial population dynamics. Our adaptive management approach accounting for hunting selectivity and demographic fluctuations can be of general relevance for harvested species in stochastic environments.