Building Resistance and Resilience: Regeneration Should Not be Left to Chance

Contemporary forest planning has tasked managers with developing goals associated with resistance and resilience. In practice, silviculturists use forest structure and tree species composition to characterize goals and desired future conditions, write prescriptions, and monitor outcomes associated with resistance and resilience. Although rarely discussed in the exploding literature relating to forest resistance and resilience, silvicultural regeneration methods are important and underutilized tools to meet these goals. We propose alternative silvicultural systems for building resistance and resilience to two common large-scale bark beetle disturbance agents in the Intermountain West, United States: mountain pine beetle (Dendroctonus ponderosae Hopkins) and spruce beetle (Dendroctonus rufipennis Kirby). Shelterwood, and shelterwood-with-reserves, silvicultural systems provide the desirable facilitative characteristics of a mature overstory on maintaining advance reproduction and the establishment of new cohorts of desirable tree species. These also allow the timely regeneration of large treatment areas necessary to rapidly promote desired future conditions in the face of inevitable disturbance. When implemented proactively, regeneration treatments allow silviculturists to take advantage of currently existing vegetation for the creation of age class and tree species diversity. In general, these examples illustrate the need for proactive planning for regeneration in response to any disturbance where desired future conditions include particular species. Furthermore, we argue that timely silvicultural interventions that focus on regenerating trees may be a key factor in achieving goals relating to resilience to specific disturbance types. Waiting until after the disturbance has occurred could result in the lost opportunity to establish desired species composition or stand structure—and may well result in a considerable restoration challenge

Landscape-Scale Drivers of Resistance and Resilience to Bark Beetles: A Conceptual Susceptibility Model

Bark beetle (Dendroctonus spp.) outbreaks in the middle latitudes of western North America cause large amounts of tree mortality, outstripping wildfire by an order of magnitude. While temperatures play an important, and direct role in the population dynamics of ectothermic bark beetles, an equally important influence is the nature of the host substrate—the structure and composition of forested communities. For many of the dominant tree species in the western United States, “hazard” indices have been developed for specific bark beetles, which generally include three key variables—host tree size, absolute or relative density of the stand, and percentage of host composition. We provide a conceptual model to apply these three variables across forest ecosystems and bark beetles that shifts the thinking from a species–specific model to a model which focuses on the underlying ecological factors related to bark beetle outbreak susceptibility. We explored the use of our model across multiple scales using the Forest Inventory and Analysis database: Interior West, USA; the states of Colorado and Arizona; and specific national forests within Arizona that are implementing a large-scale restoration effort. We demonstrated that across the Interior West and Colorado, the vast majority of forests have moderate to high susceptibility to bark beetles. Our conceptual model maintains the simplicity of previous “hazard” models but acknowledges the need to consider scale when managing bark beetles. It also shifts the management approach from resistance thinking to the development of “associational resilience”, where the focus is not on any one individual stand or area but the longer-term perspective of forest persistence across the landscape

Active tuning of high-Q dielectric metasurfaces

We demonstrate the active tuning of all-dielectric metasurfaces exhibiting high-quality factor (high-Q) resonances. The active control is provided by embedding the asymmetric silicon meta-atoms with liquid crystals, which allows the relative index of refraction to be controlled through heating. It is found that high quality factor resonances ($Q=270\pm30$) can be tuned over more than three resonance widths. Our results demonstrate the feasibility of using all-dielectric metasurfaces to construct tunable narrow-band filters.Comment: 4 pages, 6 figure

Primary spinel + chlorite inclusions in mantle garnet formed at ultrahigh-pressure

Multiphase inclusions represent microenvironments where the interaction between fluid and host mineral is preserved during the rock geological path. Under its peculiar chemical-physical constraints, the entrapped solute-rich fluid might follow a crystallisation mechanism which is not predictable through simple equilibrium arguments. In this letter, by the modelling of solid-solution equilibrium and the application of principles of mass conservation, we demonstrate that cavities in mantle garnet filled with slab-derived fluids can re-equilibrate to a pyrope + spinel + chlorite assemblage at the same high P-T of their formation. The basis of this occurrence is a dissolution-reprecipitation mechanism, triggered by a dilute, non-equilibrated slab fluid

Evaluation of seismic demand for substandard reinforced concrete structures

Background: Reinforced Concrete (RC) buildings with no seismic design exhibit degrading behaviour under severe seismic loading due to non-ductile brittle failure modes. The seismic performance of such substandard structures can be predicted using existing capacity demand diagram methods through the idealization of the non-linear capacity curve of the degrading system, and its comparison with a reduced earthquake demand spectrum. Objective: Modern non-linear static methods for derivation of capacity curves incorporate idealization assumptions that are too simplistic and do not apply for sub-standard buildings. The conventional idealisation procedures cannot maintain the true strength degradation behaviour of such structures in the post-peak part, and thus may lead to significant errors in seismic performance prediction especially in the cases of brittle failure modes dominating the response. Method: In order to increase the accuracy of the prediction, an alternative idealisation procedure using equivalent elastic perfectly plastic systems is proposed herein that can be used in conjunction with any capacity demand diagram method. Results: Moreover, the performance of this improved equivalent linearization procedure in predicting the response of an RC frame is assessed herein. Conclusion: This improved idealization procedure has been proven to reduce the error in the seismic performance prediction as compared to seismic shaking table test results [1] and will be further investigated probabilistically herein

Motor-based bodily self is selectively impaired in eating disorders

BACKGROUND: Body representation disturbances in body schema (i.e. unconscious sensorimotor body representations for action) have been frequently reported in eating disorders. Recently, it has been proposed that body schema relies on adequate functioning of the motor system, which is strongly implicated in discriminating between one’s own and someone else’s body. The present study aimed to investigate the motor-based bodily self in eating disorders and controls, in order to examine the role of the motor system in body representation disturbances at the body schema level. METHODS: Female outpatients diagnosed with eating disorders (N = 15), and healthy controls (N = 18) underwent a hand laterality task, in which their own (self-stimuli) and someone else’s hands (other-stimuli) were displayed at different orientations. Participants had to mentally rotate their own hand in order to provide a laterality judgement. Group differences in motor-based bodily self-recognition—i.e. whether a general advantage occurred when implicitly processing self- vs. other-stimuli − were evaluated, by analyzing response times and accuracy by means of mixed ANOVAs. RESULTS: Patients with eating disorders did not show a temporal advantage when mentally rotating self-stimuli compared to other-stimuli, as opposed to controls (F(1, 31) = 5.6, p = 0.02; eating disorders-other = 1092 ±256 msec, eating disorders-self = 1097±254 msec; healthy controls-other = 1239±233 msec, healthy controls -self = 1192±232 msec). CONCLUSIONS: This study provides initial indication that high-level motor functions might be compromised as part of body schema disturbances in eating disorders. Further larger investigations are required to test motor system abnormalities in the context of body schema disturbance in eating disorders

Tildrakizumab in moderate-to-severe plaque psoriasis: A multicenter, retrospective, real-life study

New biologic agents targeting interleukin (IL)23/T-helper17 axis, such as tildrakizumab, have been developed for the treatment of plaque psoriasis. To analyze the efficacy and safety of tildrakizumab in a real life setting of patients affected by moderate-to-severe psoriasis over a 28-week treatment period. A multicentric retrospective study was conducted in patients who initiated tildrakizumab between February 2020 and March 2021. Psoriasis Area and Severity Index-PASI was measured at baseline and after 4, 16 and 28 weeks. The percentage change in PASI value from baseline to the considered time-points, proportion of patients with absolute PASI <3 at week 28 and the percentages of achieving a PASI75 or PASI90 response were assessed. Data about potential safety issues and adverse events (AEs) were collected. Statistical analysis were performed for establish clinical efficacy and for variables predicting clinical response. Fifty nine patients with psoriasis were included. Overall mean PASI percentage reduction was of 88% from baseline to week 28 and 47 out of 59 patients (79.7%) at week 28 had an absolute PASI <3. PASI75 and PASI90 responses at week 28 were achieved by 48 (81.40%) patients and 38 (64.4.0%) patients, respectively. No substantial associations between gender, body mass index - BMI, PASI at baseline and prior exposition to biological therapies and the efficacy endpoints were retrieved. No serious safety issues or discontinuations related to adverse events were reported. In our real-life study, tildrakizumab showed high efficacy and a favorable safety profile, regardless of patient- and disease-related factors

General Strategy for Broadband Coherent Perfect Absorption and Multi-wavelength All-optical Switching Based on Epsilon-Near-Zero Multilayer Films

We propose a general, easy-to-implement scheme for broadband coherent perfect absorption (CPA) using epsilon-near-zero (ENZ) multilayer films. Specifically, we employ indium tin oxide (ITO) as a tunable ENZ material, and theoretically investigate CPA in the near-infrared region. We first derive general CPA conditions using the scattering matrix and the admittance matching methods. Then, by combining these two methods, we extract analytic expressions for all relevant parameters for CPA. Based on this theoretical framework, we proceed to study ENZ CPA in a single layer ITO film and apply it to all-optical switching. Finally, using an ITO multilayer of different ENZ wavelengths, we implement broadband ENZ CPA structures and investigate multi-wavelength all-optical switching in the technologically important telecommunication window. In our design, the admittance matching diagram was employed to graphically extract not only the structural parameters (the film thicknesses and incident angles), but also the input beam parameters (the irradiance ratio and phase difference between two input beams). We find that the multi-wavelength all-optical switching in our broadband ENZ CPA system can be fully controlled by the phase difference between two input beams. The simple but general design principles and analyses in this work can be widely used in various thin-film devicesopen

Large optical nonlinearity of nanoantennas coupled to an epsilon-near-zero material

The size and operating energy of a nonlinear optical device are fundamentally constrained by the weakness of the nonlinear optical response of common materials1. Here, we report that a 50-nm-thick optical metasurface made of optical dipole antennas coupled to an epsilon-near-zero material exhibits a broadband (∼400 nm bandwidth) and ultrafast (recovery time less than 1 ps) intensity-dependent refractive index n2 as large as −3.73 ± 0.56 cm2 GW−1. Furthermore, the metasurface exhibits a maximum optically induced refractive index change of ±2.5 over a spectral range of ∼200 nm. The inclusion of low-Q nanoantennas on an epsilon-near-zero thin film not only allows the design of a metasurface with an unprecedentedly large nonlinear optical response, but also offers the flexibility to tailor the sign of the response. Our technique removes a longstanding obstacle in nonlinear optics: the lack of materials with an ultrafast nonlinear contribution to refractive index on the order of unity. It consequently offers the possibility to design low-power nonlinear nano-optical devices with orders-of-magnitude smaller footprints.PostprintPeer reviewe

Congenital cardiovascular defects in children with intestinal malrotation

Intestinal malrotation (IM) and cardiovascular defects (CCVD) are both common congenital defects. We investigated the prevalence and types of CCVD in a 25-year IM population, and its association with post-IM-operative morbidity and mortality. Data on the type of CCVD, other congenital defects, syndromes, associations, post-IM-operative morbidity and mortality were retrospectively reviewed from the records of IM patients born between 1980 and 2005. Data were analyzed on (significant) differences between CCVD subgroups, and risk factors for both morbidity and mortality were calculated. Seventy-seven of 284 IM patients (27.1%) were diagnosed with a major or minor CCVD (37 and 40 patients, respectively). Syndromes and associations were more frequently diagnosed in patients with major than with a minor CCVD (67.6 vs. 40%, respectively). Post-IM-operative complications, although frequently observed (61%), did not differ between patients with major and minor CCVD. Physical CCVD signs before IM surgery increased post-IM-operative morbidity significantly (OR 4.0, 95% CI 1.4–11.0). Fifteen patients died (19.5%), seven due to cardiovascular cause. Mortality risk was increased by intestinal ischemia and post-IM-operative complications and by major CCVD after correction for age at weight at the time of IM operation. Congenital cardiovascular defects in children with intestinal malrotation are common, with high morbidity and mortality rates after IM operation. Elective IM surgery in young patients with CCVD should be performed in a centre with adequate paediatric cardiac care. Benefits of laparoscopic intervention need further study