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International audience; Aim Climate change is known to be a driver of changes in forest plant communities and to modify disturbance regimes. We investigated whether forest gaps favoured vegetation adaptation to warmer climates by accelerating the shift of plant communities to a warmer-adapted composition independently of canopy closure linked to natural forest dynamics. Location Temperate and mountainous forests of France. Time period 2002-2018. Major taxa studied Vascular plants. Methods Using floristic surveys conducted in 2002 and 2018 in 139 permanent plots set up in unmanaged forest gaps created by windstorms in 1999, we assessed the plant communities' changes in context of global warming. We also compared gap communities to closed communities inventoried in undisturbed forest. A community temperature index (CTI) and a community light index (CLI) were computed for each floristic survey with species temperature optima and Ellenberg light indicator values, respectively. Results CTI increased significantly in the gaps over the 16 years by 0.11 degrees C/decade on average. During the same period, the CLI decreased, indicating that community thermophilization was not the direct result of an increase in solar radiation linked to gap creation. Models showed that, after canopy recovery, thermophilization was stronger in mountains (+0.54 degrees C) than lowland sites (+0.12 degrees C) compared to undisturbed forests. The difference between former gaps and undisturbed forests resulted from the colonization of warm adapted species and the decline of cold adapted species in gaps. Main conclusions For a given canopy closure, our results show that thermophilization of understorey communities is higher in areas with previous disturbances than in undisturbed forests. By increasing the speed of thermophilization, the disturbance regime plays a key role in the adaptation of forest communities to climate warming. The effects of large-scale disturbances on forest plant composition should therefore not be overlooked, especially since disturbance regime tends to intensify with climate change.

Oak (Quercus petraea (Matt.) Liebl. and Quercus robur L. grouped), European beech (Fagus sylvatica L.) and hornbeam (Carpinus betulus L.) are three major species of western and central European forests. When conditions are suitable for the three species, silvicultural management often favours oak because of its greater economic interest. Forest managers know that beech and hornbeam are strong competitors for oak during the regeneration phase, but the conditions that influence the relative success of the regeneration of the three species growing in mixture are still poorly characterised. The natural regeneration of the three species 20 years after canopy openings was studied based on 108 study sites established in 2001 in French forests impacted by the windstorms Lothar and Martin in 1999. In spring and summer 2018 and 2019, all saplings over 0.1 m in height were counted, species were identified and diameter at breast height (DBH) was measured for all saplings over 1.30 m. The height of the saplings with the highest and median DBH in each plot was recorded for each species. Mixed models were used to analyse the combined effects of former stand type, distance from the edge of the gap and soil conditions on species presence, sapling abundance, DBH and height. The modelling approach highlighted the preponderant role of the initial seed rain on the presence and sapling density of the three species compared to interspecific competition or distance from the edge. The two latter factors had a secondary effect on sapling DBH and height. Beech and hornbeam saplings were more abundant than oak saplings regardless of soil conditions (on average, 3097, 3063 and 344 saplings ha−1, respectively), suggesting a strong competitive ability of these two species. Oak was present on 22% (43% for hornbeam and 68% for beech) of the studied plots, at a low density but with a height and DBH similar to that of beech or hornbeam. This result highlights the high dissemination capacity of beech and hornbeam, which prevents the establishment of a stand dominated by oak. When seeking to obtain oak-dominated stands in the lowlands of Europe, the abundance of beech and hornbeam can be a limiting factor that could lead to the disappearance of oak from large areas if no silvicultural operations are performed to promote it.

Women are underrepresented in physician leadership. Exploring the issue, researchers created a study focused on developing successful skills, behaviors and attitudes for 15 first-year female residents. In 2016, the American Association for Physician Leadership* named Advocate Health Care's Resident Leadership Develop- ment Institute the winner of its annual Leape Ahead Award. It recognizes organizations devoted to patient safety, health care improvement and developing future physician leaders. This article summarizes and includes excerpts from the comprehensive presentation that earned the award. Evaluators were impressed by the research focusing on leadership de- velopment for female residents, saying its assessment and metrics, as well as its mentoring of participants, made the program stand out. Learn about the recipient of the 2017 Leape Ahead Award, MUSC Health at Medical University of South Carolina, in our news section, which begins on page 62.

Compare individualized contrast protocol, or weight-based protocol, to standard methodology in evaluating acute pulmonary embolism. Retrospective chart review was performed on patients undergoing computed tomography angiography with standard contrast protocol (n = 50) or individualized protocol (n = 50). Computerized tomography images were assessed for vascular enhancement and image quality. Demographics were comparable, however, more patients in the individualized group were admitted to intensive care unit (48% vs 16%, P = 0.004). Vascular enhancement and image quality were also comparable, although individualized protocol had significantly fewer contrast and motion artifact limitations (28% vs 48%, P = 0.039). Fifteen percent decrease in intravenous contrast volume was identified in individualized group with no compromise in image quality. Individualized contrast protocol provided comparable vascular enhancement and image quality to the standard, yet with fewer limitations and lower intravenous contrast volume. Catheter-gauge flow rate restrictions resulting in inconsistent technologist exam execution were identified, supporting the need for further investigation of this regimen.

International audience; Plant competition and deer browsing are two main factors which limit tree recruitment. We examined natural tree-recruitment processes under continuous-tree-cover management. Changes in plant communities and tree regeneration were monitored over an eight-year period at two different sites in a temperate hardwood forest in the North-East of France. We used paired control plot (unfenced areas, free access to deer) and exclosures (fenced areas, excluding deer) at both sites. Shade-tolerant browsing-tolerant opportunistic species (beech, Fagus sylvatica at site 1 and bramble, Rubus spp. at site 2) were present in low numbers at the beginning of the study. We found that these species used a sit-and-wait strategy, waiting for opportunities to proliferate (thinning and deer exclusion). In the exclosure at site 1, beech proliferate slowly. In the exclosure at site 2, bramble proliferated enough during the first two growing seasons to prevent tree recruitment. Thus, fencing encouraged beech sapling or bramble growth, and this growth in turn was detrimental to the richness and diversity of the plant community. The two study cases presented show that both plant competition and deer browsing can be problematic for tree recruitment. Our results further suggest that excluding deer is not sufficient to enhance the growth of browse-sensitive and moderately shade-tolerant tree species such as oaks (Quercus petraea and Q. robur).

International audience; Ecologists have long argued about the modification of plant competition along abiotic gradients, and particularly along resource gradients. Through simulations, we evaluated the impact of bramble defoliation by roe deer on the response of oak seedlings to bramble presence along two resource gradients. We set up a controlled experiment crossing: (i) two light availabilities (10% and 30% incident radiation), (ii) two water regimes (normal rainfall and a reduced water regime) and (iii) three bramble defoliation modes (non-defoliated brambles, brambles defoliated in June and brambles defoliated in late July). Control plots contained no brambles. We found that, the intensity of the competition remained constant along the gradients, while the importance of the competition significantly increased with increasing resource availability. Our results further show that bramble defoliation causes a significant decrease in both competition intensity and importance and that the effect depends on both the demographic parameter and the defoliation period. Furthermore, defoliation did not change the patterns of competition intensity and importance along the resource gradients. We emphasize the importance of considering both disturbances, such as deer defoliation, and various demographic parameters related to plant phenology and plant response dynamics in the characterization of plant-plant interactions.

Deer populations have dramatically increased over the last decades in Western Europe and their browsing has affected forest vegetation, especially plant community composition. High deer browsing pressure may threaten forest ecosystems and needs to be assessed over the long run. However, few studies to date have addressed the long-term impact of deer on forest regeneration. During one regeneration phase, we assessed the impact of deer ( Cervus elaphus L. and Capreolus capreolus L.) browsing on mixed silver fir ( Abies alba Mill.)/Norway spruce ( Picea abies L. H. Karst.) stands in the Vosges Mountains in North-eastern France. For both tree species, we measured seedling and sapling density, height and diameter in 28 paired fenced – unfenced plots distributed over two sites that had been fenced 27 years ago, for 10 and 23 years respectively. We demonstrated that the presence of deer decreased the density, height and diameter of silver fir saplings, while it increased the height of Norway spruce saplings. We also noticed that the effect of fencing was very different depending on fencing duration, and that even 10 years of fencing led to changes that were still visible 17 years later. Our results confirm that deer browsing has a long-term impact on the regeneration of silver fir. Furthermore, they suggest that deer browsing may cause a species substitution, with Norway spruce gradually replacing silver fir. Such a trend would have an impact on the ecological and economical value of these forests. How browsing impacts the forest’s ability to adapt to global warming should also be considered, since browsing might impede the implementation of management policies designed to address this issue.

Objective The objective of this study was to evaluate whether trimester-specific D-dimer levels or the modified Wells score (MWS) is a useful risk stratification tool to exclude pregnant women at low risk of pulmonary embolism (PE) from diagnostic imaging. Study Design This is a prospective and retrospective cohort study. Pregnant women who underwent diagnostic imaging for suspected PE were prospectively enrolled. D-dimer serum levels were drawn, and a MWS was assigned. Pregnant women diagnosed with a PE before study launch who underwent diagnostic imaging and had a D-dimer level drawn were also evaluated. Results In this study, 17 patients were diagnosed with a PE and 42 patients had no PE on diagnostic imaging. Sixteen out of 17 patients with a PE versus 11 out of 42 without PE had an abnormal D-dimer level (p = 0.001). Four patients with a PE versus zero without a PE had an abnormal MWS (p = 0.005). The combination of a trimester-specific D-dimer level along with the MWS was abnormal in all 17 patients with a documented PE versus 11/42 (26.2%) patients without a documented PE (p = 0.001). Conclusion A combination of trimester-specific D-dimer levels along with a MWS can be used in pregnancy to triage women into a low-risk category for PE and thereby avoid radiation exposure in a majority of pregnant patients.

An improved single-cell photonic band-gap (PBG) structure with an inner row of elliptical rods (PBG-E) was tested with high power at a 60 Hz repetition rate at X-band (11.424 GHz), achieving a gradient of 128 MV/m at a breakdown probability of 3.6×10-3 per pulse per meter at a pulse length of 150 ns. The tested standing-wave structure was a single high-gradient cell with an inner row of elliptical rods and an outer row of round rods; the elliptical rods reduce the peak surface magnetic field by 20% and reduce the temperature rise of the rods during the pulse by several tens of degrees, while maintaining good damping and suppression of high order modes. When compared with a single-cell standing-wave undamped disk-loaded waveguide structure with the same iris geometry under test at the same conditions, the PBG-E structure yielded the same breakdown rate within measurement error. The PBG-E structure showed a greatly reduced breakdown rate compared with earlier tests of a PBG structure with round rods, presumably due to the reduced magnetic fields at the elliptical rods vs the fields at the round rods, as well as use of an improved testing methodology. A post-testing autopsy of the PBG-E structure showed some damage on the surfaces exposed to the highest surface magnetic and electric fields. Despite these changes in surface appearance, no significant change in the breakdown rate was observed in testing. These results demonstrate that PBG structures, when designed with reduced surface magnetic fields and operated to avoid extremely high pulsed heating, can operate at breakdown probabilities comparable to undamped disk-loaded waveguide structures and are thus viable for high-gradient accelerator applications., United States. Dept. of Energy. High Energy Physics Division (Contract DEFG02-91ER40648)

In order to understand the performance of photonic band-gap (PBG) structures under realistic high gradient, high power, high repetition rate operation, a PBG accelerator structure was designed and tested at X band (11.424 GHz). The structure consisted of a single test cell with matching cells before and after the structure. The design followed principles previously established in testing a series of conventional pillbox structures. The PBG structure was tested at an accelerating gradient of 65 MV/m yielding a breakdown rate of two breakdowns per hour at 60 Hz. An accelerating gradient above 110 MV/m was demonstrated at a higher breakdown rate. Significant pulsed heating occurred on the surface of the inner rods of the PBG structure, with a temperature rise of 85 K estimated when operating in 100 ns pulses at a gradient of 100 MV/m and a surface magnetic field of 890 kA/m. A temperature rise of up to 250 K was estimated for some shots. The iris surfaces, the location of peak electric field, surprisingly had no damage, but the inner rods, the location of the peak magnetic fields and a large temperature rise, had significant damage. Breakdown in accelerator structures is generally understood in terms of electricmore » field effects. These PBG structure results highlight the unexpected role of magnetic fields in breakdown. The hypothesis is presented that the moderate level electric field on the inner rods, about 14 MV/m, is enhanced at small tips and projections caused by pulsed heating, leading to breakdown. Future PBG structures should be built to minimize pulsed surface heating and temperature rise.« less

SUMMARY We compared the effects of epidural and intravenous morphine on analgesic effectiveness, vital signs, cortisol and catecholamine concentrations in dogs. Twelve healthy mongrel dogs undergoing experimental thora-cotomy under non-opioid general anaesthesia were randomly assigned to two groups: group A (n=6) received 0.15 mg/kg morphine epidurally, and group B (n=6) received 0.15 mg/kg morphine IV. Postoperatively, animals were observed hourly for the first 10 hours, then at 18 and 24 hours, and heart rate, systolic and diastolic blood pressure, respiratory rate and pain score were measured. Serum cortisol and plasma catecholamines were measured at 0, 2, 4, 8 and 24 hours postoperatively. Epidural morphine was associated with a significant reduction in pain, cortisol levels, systolic blood pressure (all p

A series of experiments have been conducted to investigate the critical mechanisms involved in pulsed rf breakdown. This research has examined fundamental issues such as microparticle contamination, grain boundaries, residual gas, pulse duration, field emission, and the spatial distribution of plasma during a breakdown event. The motivation of this research is to gain a clearer understanding of the processes involved in breakdown and to determine methods to increase the breakdown threshold thereby increasing the available power in high power microwave sources and accelerator components.

The efficacy of using unenhanced head computed tomography (CT scans) as a routine screening procedure prior to lumbar puncture in the emergency department is studied retrospectively by comparing opening pressure during lumbar puncture to CT scan diagnosis in 42 patients. No correlation was found between CT scan findings and opening pressure.

This paper defines a Maximum Likelihood Estimator (MLE) for the admittance matrix estimation of distribution grids, utilising voltage magnitude and power measurements collected only from common, unsychronised measuring devices (Smart Meters). First, we present a model of the grid, as well as the existing MLE based on voltage and current phasor measurements. Then, this problem formulation is adjusted for phase-less measurements using common assumptions. The effect of these assumptions is compared to the initial problem in various scenarios. Finally, numerical experiments on a popular IEEE benchmark network indicate promising results. Missing data can greatly disrupt estimation methods. Not measuring the voltage phase only adds 30\% of error to the admittance matrix estimate in realistic conditions. Moreover, the sensitivity to measurement noise is similar with and without the phase., Comment: 5 pages, Grid Edge 2023 conference