Nutritional symbionts confer structural defence against predation and fungal infection in a grain pest beetle

Many insects benefit from bacterial symbionts that provide essential nutrients and thereby extend the hosts’ adaptive potential and their ability to cope with challenging environments. However, the implications of nutritional symbioses for the hosts’ defence against natural enemies remain largely unstudied. Here, we investigated if the cuticle-enhancing nutritional symbiosis of the saw-toothed grain beetle Oryzaephilus surinamensis confers protection against predation and fungal infection. We exposed age-defined symbiotic and symbiont-depleted (aposymbiotic) beetles to two antagonists that must actively penetrate the cuticle for a successful attack: wolf spiders (Lycosidae) and the fungal entomopathogen Beauveria bassiana. While young beetles suffered from high predation and fungal infection rates regardless of symbiont presence, symbiotic beetles were able to escape this period of vulnerability and reach high survival probabilities significantly faster than aposymbiotic beetles. To understand the mechanistic basis underlying these differences, we conducted a time-series analysis of cuticle development in symbiotic and aposymbiotic beetles by measuring cuticular melanisation and thickness. The results reveal that the symbionts accelerate their host's cuticle formation and thereby enable it to quickly reach a cuticle quality threshold that confers structural protection against predation and fungal infection. Considering the widespread occurrence of cuticle enhancement via symbiont-mediated tyrosine supplementation in beetles and other insects, our findings demonstrate how nutritional symbioses can have important ecological implications reaching beyond the immediate nutrient provisioning benefits.

Paper-Based Vapor Detection of Formaldehyde: Colorimetric Sensing with High Sensitivity

We report on a novel colorimetric sensor system for highly sensitive detection of formaldehyde (FA) in the gas phase. The sensor is constructed with paper towel as a substrate coated with the sulfuric acid salt of hydroxylamine ((NH2OH)2·H2SO4) together with two pH indicators, bromophenol blue and thymol blue. Upon exposure to FA, the hydroxylamine will react with the absorbed FA to form a Schiff base (H2C=N-OH), thus releasing a stoichiometric amount of sulfuric acid, which in turn induces a color change of the pH indicator. Such a color change was significantly enriched by incorporating two pH indicators in the system. With the optimized molar ratio of the two pH indicators, the color change (from brown to yellow, and to red) could become so dramatic as to be visible to the eye depending on the concentration of FA. In particular, under 80 ppb of FA (the air quality threshold set by WHO) the color of the sensor substrate changes from brown to yellow, which can even be envisioned clearly by the naked eyes. By using a color reader, the observed color change can be measured quantitatively as a function of the vapor concentration of FA, which produces a linear relationship as fitted with the data points. This helps estimate the limit of detection (LOD), to be 10 ppb under an exposure time of 10 min, which is much lower than the air quality threshold set by WHO. The reported sensor also demonstrates high selectivity towards FA with no color change observed when exposed to other common chemicals, including solvents and volatile organic compounds. With its high sensitivity and selectivity, the proposed paper-based colorimetric sensor thus developed can potentially be employed as a low-cost and disposable detection kit that may find broad application in detecting FA in indoor air and many other environments.

P.169 Reduced radiation CT imaging for augmented reality spinal surgery applications

Background: There is growing evidence for the use of augmented reality (AR) in pedicle screw placement in spinal surgery to increase surgical accuracy, improve clinical outcomes and reduce the radiation exposure required for intraoperative navigation. Auto-segmentation is the cornerstone of AR applications because it correlates patient-specific anatomy to structures segmented from preoperative computed tomography (pCT) images. These AR techniques allow for a reduction in the radiation dose required to acquire CT images while maintaining accurate segmentation. Methods: In this study, we methodically increase the noise that is introduced into CT images to determine the image quality threshold that is required for auto-segmentation on pCT. We then enhance the images with denoising algorithms to evaluate the effect on the segmentation. Results: The pCT radiation dose is decreased to below the current lowest clinical threshold and the resulting images still produce segmentations that are appropriate for input into AR applications. The application of denoising algorithms to the images resulted in increased artifacts and decreased bone density. Conclusions: The CT image quality that is required for successful AR auto-segmentation is lower than that which is currently employed in spine surgery. Future research is required to identify the specific, clinically relevant radiation dose thresholds.

Quality Regulation on Two-Sided Platforms: Exclusion, Subsidization, and First-Party Applications

Managing the quality of complementary applications is vital to the success of a two-sided platform. While prior research has focused solely on restricting platform access based on a quality threshold, we compare three quality regulation strategies: (1) the platform excludes access to low-quality complementors, (2) it provides a fixed amount of subsidy to high-quality complementors, and (3) it develops its own high-quality applications in addition to those from third-party complementors. Our analyses reveal that the widely adopted exclusion strategy is a special case of the subsidization strategy, and it does not always benefit the platform. In contrast, both subsidization and first-party applications strategies render the platform owner better off, with higher profits, higher average quality, and a larger consumer network, but only subsidization always improves social welfare. In addition, the trade-off between subsidization and first-party applications strategies depends on the development cost of first-party applications and the fraction of high-quality complementors, but the relationship is not monotonic. Our results demonstrate that the platform does not have to sacrifice application quantity for higher application quality. With the right choices, it can profitably improve both measures simultaneously. This research provides concrete guidelines to help platform managers make decisions about regulating the quality of complementary applications. This paper was accepted by Anandhi Bharadwaj, information systems.

Swertianolin ameliorates immune dysfunction in sepsis via blocking the immunosuppressive function of myeloid- derived suppressor cells

In this study, we studied the long-term proliferation trajectory of myeloid-derived suppressor cells (MDSCs) in murine sepsis model and investigated whether swertianolin could modulate the immunosuppressive function of MDSCs. A murine sepsis model was established by cecal ligation and perforation (CLP), according to the Minimum Quality Threshold in Pre-Clinical Sepsis Studies (MQTiPSS) guidelines. The bone marrow and spleen of the mice were collected at 24 h, 72 h, 7 and 15 d after sepsis induction. The proportions of monocytic-MDSCs (M-MDSCs; CD11b+LY6G-LY6Chi) and granulocytic-MDSCs (G-MDSC, CD11b+ Ly6G+ Ly6Clow) were analyzed by flow cytometry. Then, we have investigated whether swertianolin could modulate the immunosuppressive function of MDSCs in in vitro experiments. G-MDSCs and M-MDSCs increased acutely after sepsis with high levels sustained over a long period of time. G-MDSCs were the main subtype identified in the murine model of sepsis with polymicrobial peritonitis. Furthermore, it was found that swertianolin reduced significantly interleukin-10 (IL-10), nitric oxide (NO), reactive oxygen species (ROS), and arginase production in MDSCs, while reducing MDSC proliferation and promoting MDSC differentiation into dendritic cells. Swertianolin also improved T-cell activity by blocking the immunosuppressive effect of MDSCs. Both subsets of MDSCs significantly increased in the bone marrow and spleen of the mice with sepsis, with G-MDSCs being the main subtype identified. Swertianolin effectively regulated the functions of MDSCs and reduced immune suppression.

Computer Prompt Software to Reduce Sedentary Behavior and Promote Physical Activity Among Desk-Based Workers: A Systematic Review

Objective Do computer prompt software programs at the workplace reduce sitting time and/or increase physical activity at work? Background Many products are promoted and being used in the workplace; however, their effectiveness and use are unknown or the evidence base that they work to change behavior is lacking. Method We searched for relevant papers published between 2005 and 2020. The inclusion criteria were computer prompt software programs installed as behavioral change interventions; interventions implemented during work hours and delivered through a work personal computer or laptop; and measures of sedentary behavior and/or physical activity. To minimize risk of bias, three recommended best-evidence synthesis criteria were used: random assignment, sample size, and external validity. Based on these criteria, articles were selected and evaluated. Results Six publications met the quality threshold for review. Seven articles did not meet the quality threshold. Four of the six included publications found that computer prompt software programs decreased sedentary behavior and/or increased physical activity. Two publications reported inconsistent results. Conclusions The promising results from this systematic review indicate that there is potential for computer prompt software programs to improve the health of desk-based workers. For conclusive findings, more high-quality, scientific studies are needed. Application The best-evidence publications in this review can serve as a guide in selecting and implementing computer prompt software programs at the workplace to decrease sedentary behavior and increase physical activity.

SEAMS

Memory approximation techniques are commonly limited in scope, targeting individual levels of the memory hierarchy. Existing approximation techniques for a full memory hierarchy determine optimal configurations at design-time provided a goal and application. Such policies are rigid: they cannot adapt to unknown workloads and must be redesigned for different memory configurations and technologies. We propose SEAMS: the first self-optimizing runtime manager for coordinating configurable approximation knobs across all levels of the memory hierarchy. SEAMS continuously updates and optimizes its approximation management policy throughout runtime for diverse workloads. SEAMS optimizes the approximate memory configuration to minimize energy consumption without compromising the quality threshold specified by application developers. SEAMS can (1) learn a policy at runtime to manage variable application quality of service ( QoS ) constraints, (2) automatically optimize for a target metric within those constraints, and (3) coordinate runtime decisions for interdependent knobs and subsystems. We demonstrate SEAMS’ ability to efficiently provide functions (1)–(3) on a RISC-V Linux platform with approximate memory segments in the on-chip cache and main memory. We demonstrate SEAMS’ ability to save up to 37% energy in the memory subsystem without any design-time overhead. We show SEAMS’ ability to reduce QoS violations by 75% with < 5% additional energy.

Catchment water quality in the year preceding and immediately following restoration of a drained afforested blanket bog

The restoration of drained afforested peatlands, through drain blocking and tree removal, is increasing in response to peatland restoration targets and policy incentives. In the short term, these intensive restoration operations may affect receiving watercourses and the biota that depend upon them. This study assessed the immediate effect of ‘forest-to-bog’ restoration by measuring stream and river water quality for a 15 month period pre- and post-restoration, in the Flow Country peatlands of northern Scotland. We found that the chemistry of streams draining restoration areas differed from that of control streams following restoration, with phosphate concentrations significantly higher (1.7–6.2 fold, mean 4.4) in restoration streams compared to the pre-restoration period. This led to a decrease in the pass rate (from 100 to 75%) for the target “good” quality threshold (based on EU Water Framework Directive guidelines) in rivers in this immediate post-restoration period, when compared to unaffected river baseline sites (which fell from 100 to 90% post-restoration). While overall increases in turbidity, dissolved organic carbon, iron, potassium and manganese were not significant post-restoration, they exhibited an exaggerated seasonal cycle, peaking in summer months in restoration streams. We attribute these relatively limited, minor short-term impacts to the fact that relatively small percentages of the catchment area (3–23%), in our study catchments were felled, and that drain blocking and silt traps, put in place as part of restoration management, were likely effective in mitigating negative effects. Looking ahead, we suggest that future research should investigate longer term water quality effects and compare different ways of potentially controlling nutrient release.

Balancing rules in postmortem sperm donation

Postmortem sperm donation implies the acceptance of a very low sperm quality threshold. This threshold has two important consequences: recipients will have to submit to burdensome and expensive in vitro fertilisation/intracytoplasmic sperm injection, and many more living donors will be accepted, thus making postmortem donors largely superfluous. Given these strong arguments against the use of postmortem collected sperm, a good alternative to enlarge the donor pool would be men who stored sperm for self-use and no longer have the intention to use it.

Single-Pass UAV-Borne GatorEye LiDAR Sampling as a Rapid Assessment Method for Surveying Forest Structure

Unmanned aerial vehicles (UAV) allow efficient acquisition of forest data at very high resolution at relatively low cost, making it useful for multi-temporal assessment of detailed tree crowns and forest structure. Single-pass flight plans provide rapid surveys for key selected high-priority areas, but their accuracy is still unexplored. We compared aircraft-borne LiDAR with GatorEye UAV-borne LiDAR in the Apalachicola National Forest, USA. The single-pass approach produced digital terrain models (DTMs), with less than 1 m differences compared to the aircraft-derived DTM within a 145° field of view (FOV). Canopy height models (CHM) provided reliable information from the top layer of the forest, allowing reliable treetop detection up to wide angles; however, underestimations of tree heights were detected at 175 m from the flightline, with an error of 2.57 ± 1.57. Crown segmentation was reliable only within a 60° FOV, from which the shadowing effect made it unviable. Reasonable quality threshold values for LiDAR products were: 195 m (145° FOV) for DTMs, 95 m (110° FOV) for CHM, 160 to 180 m (~140° FOV) for ITD and tree heights, and 40 to 60 m (~60° FOV) for crown delineation. These findings also support the definition of mission parameters for standard grid-based flight plans under similar forest types and flight parameters.