Significant Upward Shift Research Articles

Structural basis of the bacterial flagellar motor rotational switching.

The bacterial flagellar motor is a huge bidirectional rotary nanomachine that drives rotation of the flagellum for bacterial motility. The cytoplasmic C ring of the flagellar motor functions as the switch complex for the rotational direction switching from counterclockwise to clockwise. However, the structural basis of the rotational switching and how the C ring is assembled have long remained elusive. Here, we present two high-resolution cryo-electron microscopy structures of the C ring-containing flagellar basal body-hook complex from Salmonella Typhimurium,which are in the default counterclockwise state and in a constitutively active CheY mutant-induced clockwise state, respectively. In both complexes, the C ring consists of four subrings, but is in two different conformations. The CheY proteins are bound into an open groove between two adjacent protomers on the surface of the middle subring of the C ring and interact with the FliG and FliM subunits. The binding of the CheY protein induces a significant upward shift of the C ring towards the MS ring and inward movements of its protomers towards the motor center, which eventually remodels the structures of the FliG subunits and reverses the orientations and surface electrostatic potential of the αtorque helices to trigger the counterclockwise-to-clockwise rotational switching. The conformational changes of the FliG subunits reveal that the stator units on the motor require a relocation process in the inner membrane during the rotational switching. This study provides unprecedented molecular insights into the rotational switching mechanism and a detailed overall structural view of the bacterial flagellar motors.

Improved Alcohol Oxidation through Combined Effects of Tensile Lattice Strain and Twin Defects in Core-Shell Electrocatalysts.

The direct alcohol fuel cells (DAFCs) rely on alcohol oxidation reactions (AORs) to produce electricity, which require catalysts with optimized electronic structure to accelerate the sluggish AORs. Herein, an epitaxial growth of Pd layer onto the pentatwinned Au@Ag core-shell nanorods (NRs) is reported to synthesize highly strained Au@AgPd core-shell NRs. The tensile strain in the AgPd shell of the Au@AgPd nanorods (NRs) arises not only from the core-shell lattice mismatch but also from twinning and lattice distortion occurring at the five twinned boundaries present in the structure. Theoretical simulations prove that the presence of tensile strains in the AgPd layer leads to a significant upward shift of the d-band center of the Pd site toward the Fermi level which remarkably changes the adsorption energy of alcohols on the surface. Highly strained Au@AgPd NRs show exceptional mass activities in electrochemical oxidation of biomass-derived alcohols (ethylene glycol, ethanol, and glycerol) reaching up to 18.66, 15.6, and 7.90 A mgpd -1, respectively. These values are 23.3, 23.6, and 23.2 times higher than commercial Pd/C catalysts. This strain engineering strategy set the platform for the design and synthesis of highly efficient and versatile catalysts for the construction of high-performance DAFCs.

Identifying potential habitats of Himalayan Red Panda Ailurus fulgens (Cuvier, 1825) (Mammalia: Carnivora: Ailuridae) in Neora Valley National Park, West Bengal, India

The Himalayan Red Panda Ailurus fulgens (Cuvier, 1825) is a globally Endangered species whose population is reported to be declining in the wild. It is a priority species for the Neora Valley National Park (NVNP) since it is the flagship species of this ecosystem. Moreover, this landscape functions as an important connecting link of the Himalayan Red Panda habitat between the state of West Bengal and Sikkim. The spatial habitat of the Himalayan Red Panda in this National Park is little known. Our study attempts to identify the spatial distribution of potential habitats for the Himalayan Red Panda using the maximum entropy algorithm (MaxEnt 3.4.1). The model predicted a 55 km2 of potential habitat with the current climate scenario. With climate change, predicted potential habitats are likely to experience significant loss and upward shift to a relatively higher elevation. Hence, the management of the NVNP should identify the potential habitats and accomplish realistic goals to help conserve the Red Pandas.­­

Analysis of variations and trends of temperature over Niger central hydrological area, Nigeria, 1911–2015

Adequate information about the variations and trends of climatic variables is indispensable for the better management of the water resources and agricultural sectors. In this study, the variability and trends of the monthly, seasonal and annual temperatures ((TMIN, TMAX and TMEAN) time series were studied over Niger Central Hydrological Area, Nigeria (NCHA) during 1911–2015 using the Climate Research Unit (CRU) data. Different statistical operations analysis comprising descriptive statistics, linear regression model, Mann–Kendall test, Pettitt's test and standard normal homogeneity test (SNHT) were employed for the analysis. The tests were used to examine the temperature variability, presence of monotonic trends and change points of the time series. The monthly TMEAN variability over the entire area was between 2.10% and 3.61%. Periods 1914–1925 and 1974–1980 showed cooling trends, while 1930–1935, 1981–1988 and 2001–2015 exhibited warming trends. The annual TMIN and TMEAN showed positive trends across the 33 sub-basins of NCHA, while the TMAX showed mixed trends. The increasing trend was most significant on the monthly, seasonal and annual timescales of the TMIN, followed by TMEAN. In contrast, the mixed trends in TMAX were not significant. The global rate of change trends of TMIN, TMAX and TMEAN are 0.091, −0.007 and 0.043 °C/decade respectively. The overall warming of TMEAN also had a significant upward shift change of 0.43 °C since 1980 and the change spatially is characterized by a SW-NE orientation. There is a need to embrace green settlement and a green economy to reduce the impact of the ever-increasing warming trend over the region.

Experimental Characterization of Hydrodynamic Properties of a Deformable Rock Fracture

Characterization of stress-dependent single-phase and multiphase fluid transport in fractured geo-materials is essential for a wide range of applications, including CO2 sequestration, energy storage, and geo-energy extraction. However, pivotal studies on capillarity and multiphase fluid flow in deformable rock fractures are surprisingly sparse. In this study, we initially investigated the hydro-mechanical properties of an intact mixed-wet Calumet carbonate from the Waterways formation (Alberta) under isothermal conditions (40 °C). Then, we conducted core-flooding experiments using water and N2 to assess changes in the aperture, absolute permeability, relative permeability, and capillary pressure of an artificially fractured Calumet core in response to changes in effective confining stress during loading (0–10 MPa) and unloading (10–3 MPa). We quantified the fracture’s non-linear closure and hysteresis effect during the cyclic loading–unloading processes. We found that porosity and absolute permeability of the fracture decreased from 1.5% and 19.8 D to 1.18% and 0.22 D, respectively, during the loading. We revealed a systematic rightward shift in the relative permeability and a significant upward shift in the dynamic capillary pressure curves as the fracture deformed. This fundamental study demonstrates the critical role of fracture deformation on fluid flow in fractured rocks, which paves the way for future research in geoscience and engineering.

Robust metal-insulator transition in "112″-layered double perovskites Y1−xLnxBaCo2O5.50±δ (Ln = Sm, Eu and Gd; x = 0, 0.5 and 1)

We report the synthesis, structural, magnetic, electrical transport, magnetoelectric and thermoelectric properties of ″112″-layered double perovskite Y1−xLnxCo2O5.5 (Ln = Sm, Eu and Gd; x = 0, 0.5 and 1) cobaltites. YBaCo2O5.50 exhibits simultaneous structural, magnetic and electrical transitions around 300 K. Whereas LnBaCo2O5.50 (Ln = Sm, Eu and Gd) exhibit well separated TC and TIM, respectively, below and above 300 K. It is expected from the chemical viewpoint that the substitution of Ln by Y in LnBaCo2O5.50 should result in proximity of TC and TIM. However, our investigation demonstrates that though TC shows significant upward shift, TIM exhibits robustness. This suggests that the electrical and magnetic transitions are decoupled. The large MR [(ρH-ρ0)/ρ0] values (~50%) at low temperatures are observed for Eu and Gd-phases. The low temperature electrical conduction mechanism is of variable range hopping (VRH) type and the thermoelectric properties suggest the p-type polaronic conductivity or hole like carriers in the samples. The observed results can be understood in the framework of electronic phase separation and the metal-insulator transition from viewpoint of structural transition instead of the spin state transition.

Tetrahydrobiopterin Administration Augments Exercise-Induced Hyperemia and Endothelial Function in Patients With Systemic Sclerosis.

Systemic sclerosis (SSc) is a rare, auto-immune disease with variably progressive fibrosis of the skin and internal organs, as well as vascular dysfunction. Recently, we demonstrated a decrement in exercising skeletal muscle blood flow and endothelium-dependent vasodilation in SSc, but the mechanisms responsible for these impairments have not been investigated. Thus, we sought to determine if acute administration of tetrahydrobiopterin (BH4), an essential cofactor for endothelial nitric oxide synthase (eNOS), would improve hyperemia and brachial artery vasodilation during progressive handgrip exercise in SSc. Thirteen patients with SSc (63 ± 11 years) participated in this placebo-controlled, randomized, double-blind, crossover study. Tetrahydrobiopterin (10 mg/kg) administration resulted in a ~4-fold increase in circulating BH4 concentrations (P < 0.05). Cardiovascular variables at rest were unaffected by BH4 (P > 0.05). During handgrip exercise, BH4 administration increased brachial artery blood flow (placebo: 200 ± 87; BH4: 261 ± 115 ml/min; P < 0.05) and vascular conductance (placebo: 2.0 ± 0.8; BH4: 2.5 ± 1.0 ml/min/mmHg; P < 0.05), indicating augmented resistance artery vasodilation. Tetrahydrobiopterin administration also increased brachial artery vasodilation in response to exercise (placebo: 12 ± 6; BH4: 17 ± 7%; P < 0.05), resulting in a significant upward shift in the slope relationship between Δ brachial artery vasodilation and Δ shear rate (placebo: 0.030 ± 0.007; BH4: 0.047 ± 0.007; P < 0.05) that indicates augmented sensitivity of the brachial artery to vasodilate to the sustained elevations in shear rate during handgrip exercise. These results demonstrate the efficacy of acute BH4 administration to improve both resistance and conduit vessel endothelial function in SSc, suggesting that eNOS recoupling may be an effective strategy for improving vasodilatory capacity in this patient group.

Importance of vagal tone before atrial fibrillation onset

Neuromodulation is increasingly attempted during ablation procedures for atrial fibrillation (AF). The role of the cardiac autonomic nervous system (CANS) in triggering paroxysmal AF episodes is well-established. Heart rate variability (HRV) provides information on the final output of the influence of the CANS. The high frequency component (HF: 0.15–0.40 Hz) reflects vagal activity, and the low frequency component (LF: 0.04–0.15 Hz) reflects a complex mix of parasympathetic, sympathetic, and other unidentified non-linear factors. Therefore, clinically, the analysis of the temporality of these parameters could be useful for the selection of additional therapy during AF ablation procedures. Study the significance of CANS variations prior to AF onset by tracking the evolution of frequential parameters of HRV and premature atrial contractions (PACs). We screened our ECG Holter monitoring database of more than 20,000 patients to find those with paroxysmal AF episodes recorded. Three hundred analyzable AF onsets from 210 paroxysmal AF patients were labelled. We analyzed HRV frequential parameters by segments every 300 RR intervals, progressing beat by beat to allow the evolution of the spectral parameters of the HRV and count of PACs to be closely monitored. We focused on the evolution of low (LF) and high frequencies (HF), as well as the LF/HF ratio and the number of PACs. We observed several cyclical variations of increasing amplitude in CANS followed by a final significant upward shift in HF and LF preceding the onset of AF. The number of PACs shows a progressive increase in parallel to autonomic changes (see Fig. 1 ). These data suggest that vagal influence is preponderant in the AF onset for most of the patients. This is in favor of a thoracoscopic approach to neuromodulation procedures, as ganglionic plexi contain mainly parasympathetic neurons and are located in epicardial fat pads.

Analysis of a higher-energy structure in nanotip enhanced fields

We investigate strong field ionization of an atomic gas in a plasmonically enhanced field resulting from the illumination of a nanometer-sized structure with ultrafast laser pulse. We use perturbation theory to derive an approximate solution for electron’s motion following ionization. These analytical estimates are corroborated by the time-dependent Schrödinger equation and classical trajectory Monte Carlo simulations. Notably, our approach can be used to obtain electron energy spectra without having to rely on numerical simulations. This allows for a deeper study of the dependence of electron energy spectrum on the properties of the near-field, suggesting electric field sensor applications. We derive an analytical expression for the location of the peak of the higher-energy structure (HES) as a function of laser parameters and near-field decay length. We find a particularly strong dependence of the energy peak on laser frequency, with lower frequencies causing a significant upward shift in the final electron energies. Combined with control of the width of the HES, which can be done by changing the size of the nanostructure, this points to the possibility of using nanotips as sources of ultrashort electron beams of tunable energy.

Adolescent Intermittent Ethanol (AIE) Enhances the Dopaminergic Response to Ethanol within the Mesolimbic Pathway during Adulthood: Alterations in Cholinergic/Dopaminergic Genes Expression in the Nucleus Accumbens Shell.

A consistent preclinical finding is that exposure to alcohol during adolescence produces a persistent hyperdopaminergic state during adulthood. The current experiments determine that effects of Adolescent Intermittent Ethanol (AIE) on the adult neurochemical response to EtOH administered directly into the mesolimbic dopamine system, alterations in dendritic spine and gene expression within the nucleus accumbens shell (AcbSh), and if treatment with the HDACII inhibitor TSA could normalize the consequences of AIE. Rats were exposed to the AIE (4 g/kg ig; 3 days a week) or water (CON) during adolescence, and all testing occurred during adulthood. CON and AIE rats were microinjected with EtOH directly into the posterior VTA and dopamine and glutamate levels were recorded in the AcbSh. Separate groups of AIE and CON rats were sacrificed during adulthood and Taqman arrays and dendritic spine morphology assessments were performed. The data indicated that exposure to AIE resulted in a significant leftward and upward shift in the dose-response curve for an increase in dopamine in the AcbSh following EtOH microinjection into the posterior VTA. Taqman array indicated that AIE exposure affected the expression of target genes (Chrna7, Impact, Chrna5). The data indicated no alterations in dendritic spine morphology in the AcbSh or any alteration in AIE effects by TSA administration. Binge-like EtOH exposure during adolescence enhances the response to acute ethanol challenge in adulthood, demonstrating that AIE produces a hyperdopaminergic mesolimbic system in both male and female Wistar rats. The neuroadaptations induced by AIE in the AcbSh could be part of the biological basis of the observed negative consequences of adolescent binge-like alcohol exposure on adult drug self-administration behaviors.

Cryo-EM analysis provides new mechanistic insight into ATP binding to Ca2+ -ATPase SERCA2b.

Sarco/endoplasmic reticulum Ca2+ -ATPase (SERCA) 2b is a ubiquitous SERCA family member that conducts Ca2+ uptake from the cytosol to the ER. Herein, we present a 3.3Å resolution cryo-electron microscopy (cryo-EM) structure of human SERCA2b in the E1·2Ca2+ state, revealing a new conformation for Ca2+ -bound SERCA2b with a much closer arrangement of cytosolic domains than in the previously reported crystal structure of Ca2+ -bound SERCA1a. Multiple conformations generated by 3D classification of cryo-EM maps reflect the intrinsically dynamic nature of the cytosolic domains in this state. Notably, ATP binding residues of SERCA2b in the E1·2Ca2+ state are located at similar positions to those in the E1·2Ca2+ -ATP state; hence, the cryo-EM structure likely represents a preformed state immediately prior to ATP binding. Consistently, a SERCA2b mutant with an interdomain disulfide bridge that locks the closed cytosolic domain arrangement displayed significant autophosphorylation activity in the presence of Ca2+ . We propose a novel mechanism of ATP binding to SERCA2b.

THE INFLUENCE OF DECISIONS ON INCREASING SOCIAL STANDARDS ON MONETARY POLICY

Abstract. Raising social standards is an essential instrument of social policy by the state. However, the decision to raise the minimum wage rather sharply should consider its impact on fiscal and monetary policy. The article aims to study how government decisions on social standards (in particular minimum wages) can influence monetary policy decisions based on inflation targeting. Results of the research. The method of analysis of indicators and consequences of the introduction of inflation targeting in Ukraine, geographical neighbors and countries with similar economies is described. It is determined that the final effect of changes in social standards on inflation depends on the entire transmission mechanism, which includes several interrelated reactions, and maybe stretched over time, depending on both the speed of transmission of the impulse and the specifics of institutional regulation. It is established that the criterion for a dramatic increase in the minimum wage is a significant upward shift of the minimum wage to the average wage ratio curve. In this case, as we have shown, inflation expectations worsen, which modifies somewhat the behaviour of economic agents and is transferred to current inflation rates in the future. Raising social standards is a good decision of the government in order to maintain household incomes. However, to ensure the neutrality of such a decision for fiscal and monetary policy, it needs to be aligned with its objectives and strategies. Keywords: social standards, monetary policy, inflation targeting, minimum wage, GDP, government. JEL Classification Е 600 Formulas: 0; fig.: 3; tabl.: 1; bibl.: 17.

Abstract SP080: Hidden clues in the mammogram: How AI can improve early breast cancer detection

Abstract Innovative methods of risk assessment that leverage the strength of Artificial Intelligence (AI) are essential to propel the goals of precision prevention forward. Since the creation of the Gail model in 1989, risk models have supported risk-adjusted screening and prevention, and their continued evolution has been a central pillar of breast cancer research. Prior research has explored multiple risk factors related to hormonal and genetic information. One factor that has received substantial attention is mammographic breast density. Incorporating mammographic breast density into clinically used models such as the Gail and Tyrer-Cuzick risk models significantly improves prediction and discrimination. However, current risk models are limited in that they incorporate only a small fraction of data available on any given patient. Using breast density as a proxy for the detailed information embedded in the mammogram is extremely limited, as breast density assessment is subjective, varies widely across radiologists, and restricts the rich information contained in the digital images to a single crude value. Patients of the same age assigned the same density score can have mammogram images that appear drastically different and can have very different future risk profiles. While previous studies have explored automated methods to assess breast density, these efforts reduce the complex data contained in the mammogram into a few statistics, which are not sufficiently rich to distinguish patients who will and will not develop breast cancer. Deep learning models can operate over full resolution mammogram images to assess a patient’s future breast cancer risk. Rather than manually identifying discriminative image patterns, machine learning models can discover these patterns directly from the data. Specifically, models are trained with full resolution mammograms and the outcome of interest, namely whether the patient developed breast cancer within five years from the date of the examination. Our recent work demonstrates that application of novel artificial intelligence applications to imaging data can significantly improve breast cancer risk prediction. In addition, unlike traditional models, our DL model performs equally well across varied races, ages, and family histories and we have built a clinical platform which is currently in use to support implementation of our risk model into clinical care. The COVID-19 pandemic has revealed severe inequities in healthcare while providing opportunities for essential reform. In breast cancer care, preliminary, conservative estimates predict the disruption of breast cancer screening due to the COVID-19 pandemic will result in a significant upward stage shift of cancers diagnosed and more than 5,000 breast cancer deaths in the U.S. alone. Due to severely limited healthcare resources during pandemics, and to protect patients and healthcare workers, state governments urge providers to focus cancer screening efforts on those patients at higher risk. These mandates are necessary responses to support fair allocation of scarce resources to maximize benefits for all patients across the full spectrum of healthcare needs. AI-based breast cancer risk models have the potential to support more effective and more equitable mammographic screening for breast cancer during these times of severely restricted access to screening. ROC Area Under the Curve Analyses of Traditional vs AI Risk Models Risk ModelTyrer-Cuzick version 8 AUCAI Image Only AUCRaceAfrican American0.58 (0.39, 0.79)0.74 (0.60, 0.90)Asian0.53 (0.35, 0.74)0.79 (0.68, 0.94)White0.64 (0.60, 0.68)0.77 (0.73, 0.80)Age&amp;lt;500.65 (0.57, 0.72)0.75 (0.68, 0.82)50-700.64 (0.60, 0.69)0.76 (0.72, 0.79)&amp;gt;700.52 (0.43, 0.60)0.77 (0.70, 0.84)DensityNon-Dense0.63 (0.58, 0.68)0.77 (0.73, 0.81)Dense0.63 (0.58, 0.69)0.77 (0.73, 0.81) Citation Format: C Lehman, A Yala, L Lamb, R Barzilay. Hidden clues in the mammogram: How AI can improve early breast cancer detection [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP080.

Electrophysiological investigation of motor axonal excitability in a mouse model of nerve constriction injury.

Peripheral nerve injuries caused by focal constriction are characterised by local nerve ischaemia, axonal degeneration, demyelination, and neuroinflammation. The aim of this study was to understand temporal changes in the excitability properties of injured motor axons in a mouse model of nerve constriction injury (NCI). The excitability of motor axons following unilateral sciatic NCI was studied in male C57BL/6J mice distal to the site of injury at the acute (6 hours-1 week) and chronic (up to 20 weeks) phases of injury, using threshold tracking. Multiple measures of nerve excitability, including strength-duration properties, threshold electrotonus, current-threshold relationship, and recovery cycle were examined using the automated nerve excitability protocol (TRONDNF). Acutely, injured motor axons developed a pattern of excitability characteristic of ischemic depolarisation. In most cases, the sciatic nerve became transiently inexcitable. When a liminal compound muscle action potential could again be recorded, it had an increase in threshold and latency, compared to both pre-injury baseline and sham-injured groups. These axons showed a greater threshold change in response to hyperpolarising threshold electrotonus and a significant upward shift in the recovery cycle. Mathematical modelling suggested that the changes seen in chronically injured axons involve shortened internodes, reduced myelination, and exposed juxtaparanodal fast K+ conductances. The findings of this study demonstrate long-term changes in motor excitability following NCI (involving alterations in axonal properties and ion channel activity) and are important for understanding the mechanisms of neurapraxic injuries and traumatic mononeuropathies.

The upward elevational shifts of pond breeding amphibians following climate warming

While poorly dispersing taxa such as amphibians may have limited scope to track recent and rapid climate change by means of large range shifts, they may follow their climate envelope with short elevational shifts in mountain areas. Such elevational shifts are poorly documented by empirical data for amphibians. In this study, we analysed a 15-year data series on the distribution of three amphibian species (Bufo bufo, Triturus carnifex and Rana temporaria) inhabiting a mountain pond network in the southern Italian Alps, where temperatures have increased significantly over the last decades. By using multi-season occupancy models, we estimated the occupancy trend of each species over the study period and tested the occurrence of an actual elevational shift after accounting for the probability of false absence. The upper elevational limit of the two eurythermal species (B. bufo and T. carnifex) underwent a significant and progressive upward shift of ca. 200 m. Our results provide evidence of the ability of amphibians to perform rapid elevational shifts, great enough to track predicted rates of climate warming. Preserving and improving habitat connectivity between lowlands and highlands could safeguard the opportunity for such elevational migrations, but mountain aquatic habitats must be preserved in order to provide a safe refuge for amphibians escaping climate warming.

Structural change to the persistence of the urban heat island

The term urban heat island (UHI) is used to describe the effect of urban temperatures rising several degrees above concurrent temperatures in surrounding suburban or rural areas. This is typically assessed through records of daily extreme temperatures. However, on a hot day the temperature can exceed an extreme threshold for several consecutive hours, forming a cluster of extremes. We use the statistical theory of extreme values combined with a model that allows structural breaks to show that there has been a significant upward shift in the length of clusters in New York City. No such shift is found at a Connecticut location where the usual UHI assessment indicates that the two sites are comparable. Our study is the first to highlight this danger of the UHI. Prolonged exposure to extreme temperatures has deleterious effects on both health and the environment.

Competition and demography rather than dispersal limitation slow down upward shifts of trees’ upper elevation limits in the Alps

Abstract Species range limits are expected to be dramatically altered under future climate change and many species are predicted to shift their distribution upslope to track their suitable conditions (i.e. based on their niche). However, there might be large discrepancies between the speed of the upward shift of the climatic niche and the actual migration velocity of the species, especially in long‐lived organisms such as trees. In fact, most studies did not find any significant upward shift of the distributional limits of temperate forest trees over the last decades. It therefore beckons the questions why trees are moving upslope much slower than their bioclimatic envelope and what are the implications for ecosystem functioning. Here, we compared the simulations of the upslope displacement of the bioclimatic envelope of 16 tree species inhabiting temperate mountain forests under ongoing and future climate change obtained by correlative species distribution models (SDMs) to those from a dynamic forest model accounting for dispersal, competition and demography. We then partitioned the discrepancy in upslope migration velocity between the SDMs and the dynamic forest model into different components by manipulating dispersal limitation, interspecific competition and demography. Tree species in the dynamic forest model migrated only slowly upslope in contrast to the SDMs. Most of the difference in migration velocity can directly be attributed to tree's demography (long life cycle), followed by effects of competition and only a marginal contribution of dispersal limitation. Additionally, lower elevation species (‘non‐treeline’) shifted slower upslope than high elevation species (‘treeline’) indicating a strong effect of interspecific competition at their leading edge. Synthesis. Forests have a high inertia to climate change because of their longevity and ability to acclimatize to high climatic fluctuations. Lower elevation tree species (deciduous) only slowly establish in stands at higher elevation where coniferous species dominate and likely profit from facilitation by disturbance events. Therefore, forest ecosystems seem to persist, even if climate becomes unfavourable, until they approach a tipping point at which an extreme event (e.g. drought, storm or insect attack) leads to a large dieback and resource change enabling new suitable species to spread and establish.

A Closer Look at Nonparticipants during and after the Great Recession

This paper uses matched individual-level data from the Current Population Survey to determine that around the 2008 recession, there was a significant upward shift in trend of the share of labor force leavers giving Schooling and Other as the reason for absence from the labor market. This trend shift is observed primarily among workers between the ages of 25 and 54 and is widespread across all educational groups with at least a high school degree. In addition, the upward shift in the trend of the schooling reason share occurred among workers previously employed in occupations and industries with varying degrees of job losses during the recession. This shift suggests it was a widespread phenomenon and not isolated among sectors or occupations that suffered the most during the recession. The implication is that the upward shift in the schooling reason share has more likely been a response to lower opportunity costs of schooling during economic downturns rather than the result of workers trying to overcome skill mismatch in the labor market. In addition, since transition rates to the labor force are highest among those giving Schooling and Other as reasons for absence, the decline in labor force participation since 2008 is likely more transitory than permanent.

Potential Elevation Shift of the European Beech Stands (Fagus sylvatica L.) in Serbia.

According to climate projection models, the global temperature is expected to rise by at least 1.5°C by the end of this century. According to some studies the expected rise in Serbia is even higher. Global warming may result in creating new areas for forest growth. Although creating new forests would be a positive outcome in some areas, global warming can cause negative impacts in other areas, and this can lead to forest loss and the shift of geographical ranges, or even extinction, of plant species. The European beech is the dominant forest tree species in Serbia, featuring high ecological importance and economic value. In mixed or pure stands, beech forests cover approximately 660,400 ha, accounting for 29.3% of the total Serbian forest area. In the present study, the effects of climate change on the distribution of the European beech stands in Serbia, with an emphasis on their elevation shifts, were examined using species distribution models (SDMs). Data for the present tree cover in Serbia, climate projections, and environmental data were used for model building. The models were first tested against present inventory data. In these tests, the models were found to provide accurate projections, as shown by their true skills statistics (TSS) values ranging from 0.652 to 0.736 and area under the curve (AUC) values ranging from 0.868 to 0.937. The potential distribution patterns predicted by the models indicate that the European beech elevational distribution in Serbia would decrease, exhibiting a significant upward shift in elevation during the first part of this century. Current beech stand locations could be changed, and other areas at higher elevations may be more suitable for beech growth. After 2071, European beech stands at elevations below 500 m would be even smaller. This change is caused by temperature rise and occurrence of climate extremes. However, on the highest elevations, further upward shift of the species is not expected.

The stability of spruce treelines on the eastern Tibetan Plateau over the last century is explained by pastoral disturbance

Most Tibetan people make their living through pastoralism, with livestock grazing being widespread throughout the Tibetan Plateau. The Tibetan Plateau is also home to the northern hemisphere’s highest treelines but the effects of human activities, in particular pastoralism, on these treelines and their influence on the treeline responses to climate change remain unclear. To disentangle the effects of pastoral disturbances and climate on treeline dynamics, we surveyed three plots at grazing-disturbed Balfour spruce (Picea likiangensis var. balfouriana) treelines in the Yushu region (eastern Tibetan Plateau) and compared this data with published results of five undisturbed spruce treeline sites. Spatiotemporal changes in the position and structure of treelines during the past 400 years were reconstructed using dendrochronology. Tree recruitment was significantly linked to long-term summer and winter temperature. Under low local population densities and grazing pressure but consistent climate warming, disturbed treelines shifted upwards by 23.9–82.6 m during the 1611–1910 period. However, under higher local population densities, increased grazing pressure and climate warming over the last century, disturbed treelines showed no significant upward shift. In contrast, undisturbed treelines shifted upward by 25–68.5 m over the last century, thus implying that pastoralism was suppressing treeline expansion in disturbed sites. Together, these results underscore the importance of anthropogenic disturbances in influencing the structure and position of alpine treelines on the Tibetan Plateau. The role played by human disturbance should be carefully considered when evaluating the potential for treeline advance under future climate warming.