Slow Shift Research Articles

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.

Asynchronous Prediction of Human Gait Intention in a Pseudo Online Paradigm Using Wavelet Transform.

Prediction of human voluntary gait intention is a very significant task to ensure direct cortical control of real-life assistive technologies for locomotion rehabilitation. Neurophysiological studies provide that human voluntary gait intention is represented by slow DC potentials and power shifts in specific frequency ranges of brain wave, which can be detected 1.5- 2 seconds before the actual onset. The goal of this study was to determine whether it is possible to reliably detect the intention of voluntary gait 'starting' and 'stopping' intention before it takes place. A computational algorithm was designed to implement asynchronous prediction of gait intention in an offline and pseudo-online environment using support vector machine. Six healthy subjects participated in the study and performed self- paced voluntary gait cycles. A combination of advanced wavelet transform algorithms resulted in 88.23± 1.59% accuracy, 85.42± 4.03% sensitivity and 90.24± 2.78% specificity for intention of start detection and 87.04± 1.72% accuracy, 82.69± 4.13% sensitivity and 89.59± 3.04% specificity for intention to stop walking in offline testing. Additionally, the wavelet transform methods accompanied with threshold regulation and majority voting algorithm resulted in a True Positive Rate of 85.5± 5.0% and 81.2± 3.3% for 'start' and 'stop' prediction with 6.8± 0.7 and 9.4± 1.0 False Positives per Minute respectively in pseudo online testing. The average detection latencies were -1002 ± 603 ms and -943 ± 603 ms, respectively, for 'start' and 'stop' prediction. The study provides promising outcomes in terms of TPR, FP/min, and detection latency, which suggests that human voluntary gait intention can be predicted before the onset of movement.

Secondary somatosensory area is involved in vibrotactile temporal-structure processing: MEG analysis of slow cortical potential shifts in humans

Purpose: Temporal-structure discrimination is an essential dimension of tactile processing. Exploring object surface by touch generates vibrotactile input with various temporal dynamics, which gives diversity to tactile percepts. Here, we examined whether slow cortical potential shifts (SCPs) (<1 Hz) evoked by long vibrotactile stimuli can reflect active temporal-structure processing.Materials and methods: Vibrotactile-evoked magnetic brain responses were recorded in 10 right-handed healthy volunteers using a piezoelectric-based stimulator and whole-head magnetoencephalography. A series of vibrotactile train stimuli with various temporal structures were delivered to the right index finger. While all trains consisted of identical number (15) of stimuli delivered within a fixed duration (1500 ms), temporal structures were varied by modulating inter-stimulus intervals (ISIs). Participants judged regularity/irregularity of ISI for each train in the active condition, whereas they ignored the stimuli while performing a visual distraction task in the passive condition. We analysed the spatiotemporal features of SCPs and their behaviour using the minimum norm estimates with the dynamic statistical parametric mapping.Results: SCPs were localized to contralateral primary somatosensory area (S1), contralateral superior temporal gyrus, and contralateral as well as ipsilateral secondary somatosensory areas (S2). A significant enhancement of SCPs was observed in the ipsilateral S2 (S2i) in the active condition, whereas such effects were absent in the other regions. We also found a significant larger amplitude difference between the regular- and irregular-stimulus evoked S2i responses during the active condition than during the passive condition.Conclusions: This study suggests that S2 subserves the temporal dimension of vibrotactile processing.

MUHAMMADIYAH URBAN: AKSELERASI GERAKAN MUHAMMADIYAH GRESIK KOTA BARU

This paper reveals the phenomenon that occurred in Muhammadiyah Gresik Kota Baru which, where there is a close relationship between Muhammadiyah and the middle class as the backbone of its movement. It is suspected that an accelerating move occurred in a relatively short time, Muhammadiyah Gresik Kota Baru increased rapid progress. One of the dynamics of Indonesian society that is considered important to be observed is the existence of a slow but sure shift to the sociological conditions and the religiosity of the community. Then created a group of people who came to be called the middle class. This middle class is knowledgeable, highly educated, well-established and open-minded. The next stage, they are determined as: Urban society. Since its inception, Muhammadiyah as a religiously based community organization has ties for the whole community. Muhammadiyah always undertakes multi-step revitalization of its dakwah. These efforts have so far been carried out regularly and regularly and touches almost all layers of society as objects (and subjects) of their missionary movements. This group of people is no exception: Urban society.

Spatial Dimension of Unemployment: Space-Time Analysis Using Real-Time Accessibility in Czechia

This paper focuses on the analysis of unemployment data in Czechia on a very detailed spatial structure and yearly, extended time series (2002–2019). The main goal of the study was to examine the spatial dimension of disparities in regional unemployment and its evolutionary tendencies on a municipal level. To achieve this goal, global and local spatial autocorrelation methods were used. Besides spatial and space-time analyses, special attention was given to spatial weight matrix selection. The spatial weights were created according to real-time accessibilities between the municipalities based on the Czech road network. The results of spatial autocorrelation analyses based on network spatial weights were compared to the traditional distance-based spatial weights. Despite significant methodological differences between applied spatial weights, the resulting spatial pattern of unemployment proved to be very similar. Empirically, relative stability of spatial patterns of unemployment with only slow shift of differentiation from macro- to microlevels could be observed.

Realist avenues to global International Relations

Realism has long been criticized by global IR, but the former can contribute to the latter and thereby improve explanations of international relations. Global IR criticizes that realism supposedly applies universally, sidelines non-Western perspectives, and misunderstands much of foreign policy, grand strategy, and international affairs. Reviewing global IR’s case against realism, however, exposes avenues for realism to complement global IR. Realism can contribute to a more global understanding of international relations through its most recent variant: neoclassical realism (NCR). This newest realism allows for contextualization and historicization of drivers of state behavior. It can embrace and has already been engaging global questions and cases; global thought and concepts; and global perspectives and scholarship. Mapping 149 NCR publications produced by 96 scholars reveals a slow shift in knowledge production away from North America toward Europe and to a lesser extent Asia and Africa. Creative research designs and scholarly collaboration can put realism in fruitful conversation with global IR. This has implications for theory building and inclusive knowledge production in realism, global IR, and the wider discipline. Only when we discover new avenues for realists to travel can they contribute to a more global IR. In turn, when global IR scholars engage realism, they may be better able to address the Western versus non-Western dichotomies they challenge.

The changing roles and qualifications of Canadian university presidents and provosts

This paper examines how the stated roles and qualifications of Canadian university presidents and provosts have evolved over the past thirty years and the growing presence of recruiting firms. The study analysed 153 job advertisements published by 22 universities between 1987 and 2017. Roles were categorized according to aspects of organizational life: human resource, political, structural, and symbolic, while we distinguished qualifications as involving traits as well as cultural, human, and social “capitals.” Overall, the expected qualifications for presidential and provostial candidates have increased consistently and their roles have expanded in scope. Trait qualifications and symbolic roles, while mostly absent in 1987, became prevalent by 2017, suggesting a slow but clear shift towards managerialist and charismatic depictions of leadership. This increase took place concurrently with universities’ increasing reliance on recruiting firms.

Information gain modulates brain activity evoked by reading

The human brain processes language to optimise efficient communication. Studies have shown extensive evidence that the brain’s response to language is affected both by lower-level features, such as word-length and frequency, and syntactic and semantic violations within sentences. However, our understanding on cognitive processes at discourse level remains limited: How does the relationship between words and the wider topic one is reading about affect language processing? We propose an information theoretic model to explain cognitive resourcing. In a study in which participants read sentences from Wikipedia entries, we show information gain, an information theoretic measure that quantifies the specificity of a word given its topic context, modulates word-synchronised brain activity in the EEG. Words with high information gain amplified a slow positive shift in the event related potential. To show that the effect persists for individual and unseen brain responses, we furthermore show that a classifier trained on EEG data can successfully predict information gain from previously unseen EEG. The findings suggest that biological information processing seeks to maximise performance subject to constraints on information capacity.

DEVELOPMENT OF E-HEALTH IN AUSTRIA, BULGARIA, CROATIA, ESTONIA AND SLOVAKIA

Electronic health services (e-Health) are now a fixed element of the health care system and cover a wide range of applications, such as the electronic health insurance card, the health record and an overview of medications, plus telemedicine. A prerequisite for this is the secure transmission of medical data for preventive medicine, diagnosis, treatment and the ongoing support of patients in the form of text, sound recordings and/or images.&#x0D; Uneven development of eHealth solutions within the EU27 remains a major obstacle in providing European citizens with a satisfying access to cross-border healthcare and the main challenge for the EU is harmonizing the systems. The slow shift of the paradigm centralizing the role of the patient will become more rapid making our assumptions about the savings thanks to the technology even more conservative than they are. Building on the trust that Europeans have in health institutions and the way they convey themselves is essential.

Temperature and hydrostatic pressure effects on the electronic structure, optical properties of spherical segment quantum dot/wetting layer and group velocity of light

To investigate hydrostatic pressure and temperature effects on electron energy levels of an InAs spherical segment quantum dot with wetting layer embedded in GaAs barrier, we use the finite element method to solve the Schrödinger equation in the effective mass approximation. Results show that the ground, the first and the second excited state energies decrease (increase) as the hydrostatic pressure (temperature) increases for the constant temperature (pressure). Moreover, given the optical properties of the system interacting with two laser fields, red (blue) shifts are observed in the linear and nonlinear absorptions and dispersions for the probe pulse as the hydrostatic pressure (temperature) increases. Furthermore, as the hydrostatic pressure increases, the maximum of the group velocity of light inside the slow light frequency range increases and the slow light frequency range shifts to the lower probe frequencies.

Tree‐to‐tree interactions slow down Himalayan treeline shifts as inferred from tree spatial patterns

AbstractAimThe spatial patterns of tree populations reflect multiple ecological processes. However, little is known on whether these patterns mediate responses to climate in marginal tree populations such as those forming alpine tree lines. We examined the influence of tree‐to‐tree interactions on the responsiveness of tree lines to climate warming.LocationCentral Himalayas.TaxonBetula utilis; Abies spectabilis.MethodsWe analysed a network of 17 tree line sites located across the central Himalayas, encompassing a wide longitudinal gradient characterized by increasing precipitation eastwards. We quantified the changes in density and the spatial patterns of three 50‐year age classes of the two main tree species found at the tree line (Betula utilis and Abies spectabilis), and related them to reconstructed shifts in tree line elevation.ResultsYounger trees showed clustering near the tree line, while older trees tended to show random spatial distribution. Clustering decreased as climate conditions ameliorated, that is, in the wetter eastern sites. Lower rate of tree line elevation change was observed at the sites with higher clustering intensity.Main ConclusionsOur study indicates that tree aggregation weakens tree line responsiveness to climate warming, and thus warming‐induced drought stress tends to lower tree line shift rates by enhancing clustering. It also highlights the complexity and contingency of site‐dependent tree line responses to climate. Hence, to advance our understanding of tree line processes, we should consider both direct and indirect influences of relevant biotic (tree‐to‐tree interactions) and abiotic (climate) drivers of tree line dynamics.

Investigations on structural and optical properties of Al-modified ZnO nanoparticles

The current studies are concentrated on the synthesis of Al-modified ZnO nanoparticles prepared through sol–gel method for their structural and optical properties. The wurtzite structure with single phase formation for all the samples was confirmed from the Rietveld analysis on XRD data. Nano-crystalline nature (having particle size (~ 10 to 30 nm)) of all the synthesized samples have been examined by XRD and TEM data. Optical properties were carried out from UV–Vis, FTIR and Raman spectroscopy techniques. FTIR and Raman analysis also confirms the wurtzite structure and tetrahedral configuration with coordination of oxygen ions nearby the zinc ions. The UV–Vis measurement confirms that the bandgap is blue-shifted and slow red shift for lower and higher Al-concentrations in ZnO, respectively. Visible emission spectra of PL confirms the photo generated holes with deep-level emission, which is ascribed to recombination of electrons intensely spellbound in oxygen vacancies and zinc interstitials.

Pattern Recognition in Epileptic EEG Signals via Dynamic Mode Decomposition

In this paper, we propose a new method based on the dynamic mode decomposition (DMD) to find a distinctive contrast between the ictal and interictal patterns in epileptic electroencephalography (EEG) data. The features extracted from the method of DMD clearly capture the phase transition of a specific frequency among the channels corresponding to the ictal state and the channel corresponding to the interictal state, such as direct current shift (DC-shift or ictal slow shifts) and high-frequency oscillation (HFO). By performing classification tests with Electrocorticography (ECoG) recordings of one patient measured at different timings, it is shown that the captured phenomenon is the unique pattern that occurs in the ictal onset zone of the patient. We eventually explain how advantageously the DMD captures some specific characteristics to distinguish the ictal state and the interictal state. The method presented in this study allows simultaneous interpretation of changes in the channel correlation and particular information for activity related to an epileptic seizure so that it can be applied to identification and prediction of the ictal state and analysis of the mechanism on its dynamics.

Ultrafast carrier relaxation dynamics of photoexcited GaAs and GaAs/AlGaAs nanowire array.

Femtosecond optical pump-probe spectroscopy is employed to elucidate the ultrafast carrier nonradiative relaxation dynamics of bare GaAs and a core-shell GaAs/AlGaAs semiconductor nanowire array. Different from the single nanowire conventionally used for the study of ultrafast dynamics, a simple spin coating and peeling off method was performed to prepare transparent organic films containing a vertical oriented nanowire array for transient absorption measurement. The transient experiment provides the direct observation of carrier thermalization, carrier cooling, thermal dissipation and band-gap energy evolutions along with the carrier relaxations. Carrier thermalization occurs within sub-0.5 ps and proceeds almost independently on the AlGaAs-coating, while the time constants of carrier cooling and thermal dissipation are increased by an order of magnitude due to the AlGaAs-coating effect. The concomitant band-gap evolutions in GaAs and GaAs/AlGaAs include an initial rapid red-shift in thermalization period, followed by a slow blue and/or red shift in carrier cooling, and then by an even slower blue shift in thermal dissipation. The evolution is explained by the competition of band-gap renormalization, plasma screening and band-filling. These findings are significant for understanding the basic physics of carrier scattering, and also for the development of flexible optoelectronic devices.

When is the brain ready for mental actions? Readiness potential for mental calculations

While the preparatory neural mechanisms of real and imagined body movements have been extensively studied, the underpinnings of self‑initiated, voluntary mental acts are largely unknown. Therefore, using electroencephalography (EEG), we studied the time course and patterns of changes in brain activity associated with purely mental processes which start on their own, without an external or interoceptive stimulation. We compared EEG recordings for decisions to perform mental operations on numbers, imagined finger movements, and actual finger movements. In all three cases, we found striking similarities in slow negative shifts of brain electrical activity lasting around 1 s and, therefore, characteristic for readiness potential. These results show that the brain not only needs time to be ready for a purely mental task but also that a required preparatory interval involves neural changes analogical to the ones observed before intentional body movements. As such, the readiness potential represents a universal process of unconscious preparatory brain activity preceding any, including purely mental, voluntary action.

Computational Implementation and Asymptotic Statistical Performance Analysis of Range Frequency Autocorrelation Function for Radar High-Speed Target Detection

The range frequency autocorrelation function (RFAF) based algorithm is proposed for radar target detection and motion parameter estimation in our previous work. In the RFAF-based method, the symmetric autocorrelation function (SAF) is constructed with respect to the range frequency, and three dimensional (slow time, range frequency, and shift frequency) energy accumulation can be completed coherently. In this article, as a further study of the RFAF-based method, the fast implementation and detailed asymptotic statistical performance analyses of RFAF are studied. First, on the basis of the frequency circular convolution theorem, the fast implementation is proposed. Then, to evaluate the anti-noise performance and estimation accuracy, the output signal to noise ratio (SNR) and asymptotic mean square errors (AMSEs) of estimated parameters are derived in closed forms. Theoretical analyses and numerical simulation results reveal that the RFAF-based method outperforms several state-of-the-art algorithms in terms of anti-noise performance and parameter estimation accuracy, and its computational efficiency is high.

Ammonia Induces a Myostatin-Mediated Atrophy in Mammalian Myotubes, but Induces Hypertrophy in Avian Myotubes

Ammonia, a byproduct of protein catabolism that is generally regarded as toxic, is processed by the liver for excretion. In diseases resulting in hepatic insufficiency, circulating ammonia levels increase dramatically, ensuing secondary disorders. Sarcopenia, or loss of muscle mass, is commonly associated with hyperammonemia. In mammalian models of cirrhosis, increased myostatin is consistent, contributes to muscle autophagy, and reduces satellite cell activation and differentiation, whereas, avian species show a positive myogenic response to ammonia. The objective of the study was to elucidate the effect of ammonia in chicken, mouse, and rat derived myotubes. Primary myoblasts were isolated from the pectoralis major (breast) and biceps femoris (thigh) of embryonic day 17 chicken embryos, and from the hindlimbs of 3-day-old rat pups. C2C12 cells were used for mouse myoblasts. Myotubes were exposed to 10mM ammonium acetate (AA) or 10mM sodium acetate (SA) for 24 hours to determine myogenic response to ammonia. Relative expression of myostatin mRNA, determined by quantitative real-time PCR, was significantly higher in mammalian myotubes compared to chicken myotubes (P < 0.001). Western blot analysis of myostatin protein confirmed a significant increase in ammonia treated rat myotubes, while chicken breast myotubes showed a significant decrease in myostatin (P < 0.05). Myotube diameter significantly increased in chicken breast and thigh cultures treated with ammonia, while diameter was significantly reduced in mouse and rat myotubes (P < 0.05). Intracellular glutamine is significantly higher in chicken thigh, but not breast, myotubes treated with AA compared to SA treated myotubes (P < 0.05). To investigate fiber type differences in ammonia metabolism, Western blot analysis of protein from AA and SA treated myotubes was examined for fast and slow myosin heavy chain isoforms. AA treatment resulted in a higher ratio of fast to slow isoforms of myosin heavy chain in both types of chicken myotubes, while fast isoforms were decreased in AA treated mouse and rat myotubes. These data demonstrate that chicken myotubes respond positively to ammonia while rodent myotubes respond negatively. Further, there is evidence that ammonia induces a fast fiber type shift in avian muscle, but a slow phenotype shift in mammalian muscle.

The Rise of Transportation Electrification

In the United States, where transportation accounts for 29 percent of total energy use per year, the country is witnessing a slow but steady shift from gasoline and diesel fuel to electricity—with electric vehicles (EVs) now forecast to become 11 percent of all passenger vehicle sales by 2025, and 55 percent by 2040. At this rate, the sector is expected to reach a $567 billion market size by 2026—a nearly $500 billion increase from 2017. Signs of this growth abound, from the many Teslas, Chevrolet Bolts, and Nissan Leafs on the roads to the charging stations sprouting up in public and commercial parking lots. Most automakers are planning for EVs to eclipse conventional vehicle manufacturing within the decade.

Fast and Slow Electromagnetic Waves in a Longitudinally Magnetized Thin-Film Ferromagnetic Metamaterial

We present the results of a theoretical study of the electrodynamic characteristics of fast and slow electromagnetic waves (EMWs) propagating in a metamaterial consisting of a ferromagnetic film inside which there is a periodic lattice of thin metal wires. The ferromagnetic thin-film metamaterial possesses the properties of a left-handed medium at frequencies of slow electromagnetic waves. In a ferromagnetic metamaterial, in comparison with a conventional ferromagnetic film, the cutoff frequencies of fast and slow electromagnetic waves shift to a higher frequency range and the electromagnetic waves themselves become very slow.

A score to map the lateral nonprimary motor area: Multispectrum intrinsic brain activity versus cortical stimulation.

Multispectrum electrocorticographic components are critical for mapping the nonprimary motor area (NPMA). The objective of this study was to derive and validate a reliable scoring system for electrocorticography-based NPMA mapping (NPMA score) to replace electrical cortical stimulation (ECS) during brain surgery. We analyzed 14 consecutive epilepsy patients with subdural electrodes implanted in the frontal lobe at Kyoto University Hospital. The NPMA score was retrospectively derived from multivariate analysis in the derivation group (patients=7, electrodes=713, during 2010-2013) and validated in the validation group (patients=7, electrodes=772, during 2014-2017). We assessed the accuracy and reliability of the score relative to ECS in determining the NPMA and predicting postoperative functional outcomes. Multivariate analysis in the derivation group led to an 8-point score for predicting ECS-based NPMA (1 point for anatomical localization of the electrode and 1 or 2 points for movement-related electrocorticographic components regardless of somatotopy in very slow cortical potential shifts [<0.5Hz], 40-80-Hz band power increase, and 8-24-Hz band power decrease), which was validated in the validation group. The area under the receiver operating characteristic curve (AUC) was 0.89 in the derivation group. Good prediction (specificity = 94%, sensitivity = 100%) and discrimination (AUC=0.87) were reproduced in the validation group. Overall, higher NPMA scores identified 2 patients with postoperative deficits after frontal lobe resection. The NPMA score is reliable for NPMA mapping, potentially replacing ECS. It is a potential prognostic marker for postoperative functional deficits.