Improvement of the Zienkiewicz–Zhu Error Recovery Technique Using a Patch Configuration

The Zienkiewicz–Zhu (ZZ) super-convergent patch recovery technique based on a node neighborhood patch configuration is used most widely for recovery of the stress field of a finite element analysis. In this study, an improved ZZ recovery technique using element neighborhood patch configuration is proposed. The improved recovery procedure is based on recovery of the stress field in the least-squares sense over an element patch that consists of the union of the elements surrounding the element under consideration. The proposed patch configuration provides more sampling points and improves the performance of the standard ZZ recovery technique. The effectiveness and reliability of the improved ZZ recovery approach is demonstrated through plane elastic and plastic plate problems. The problem domain is discretized with triangular and quadrilateral elements of different sizes. A comparison of the quality of error estimation using the ZZ recovery of derivative field and recovery of the displacement field using similar element neighborhood patch configurations is also presented. The numerical results show that the ZZ recovery technique and the displacement recovery technique, using a modified patch configuration, yield better results, convergence rate, and effectivity as compared with the standard ZZ super-convergent patch recovery technique. It is concluded that the improved ZZ recovery technique-based adaptive finite element analysis is very effective for converging a predefined accuracy with a significantly smaller number of degrees of freedom, especially in an elastic problem. It is also concluded that the improved ZZ recovery technique captures the plastic deformation problem solution errors more reliably than the standard ZZ recovery technique.

Landscape configuration affects probability of apex predator presence and community structure in experimental metacommunities

Biodiversity is declining at an unprecedented rate, highlighting the urgent requirement for well-designed protected areas. Design tactics previously proposed to promote biodiversity include enhancing the number, connectivity, and heterogeneity of reserve patches. However, how the importance of these features changes depending on what the conservation objective is remains poorly understood. Here we use experimental landscapes containing ciliate protozoa to investigate how the number and heterogeneity in size of habitat patches, rates of dispersal between neighbouring patches, and mortality risk of dispersal across the nonhabitat ‘matrix’ interact to affect a number of diversity measures. We show that increasing the number of patches significantly increases γ diversity and reduces the overall number of extinctions, whilst landscapes with heterogeneous patch sizes have significantly higher γ diversity than those with homogeneous patch sizes. Furthermore, the responses of predators depended on their feeding specialism, with generalist predator presence being highest in a single large patch, whilst specialist predator presence was highest in several-small patches with matrix dispersal. Our evidence emphasises the importance of considering how top-down effects can drive community responses to patch configuration.

Design of Circular Microstrip Patch Antenna for WLAN Application

A roundabout microstrip fixes receiving wire is planned in this paper. The recommended receiving wire for remote neighborhood [WLAN] utilizes a 2.4GHz resounding recurrence. There are numerous different sorts of receiving wires, however, we'll zero in on roundabout radio wires, which are worked to support the resounding recurrence referenced previously. As a result of this recurrence determination, the radio wire is ideal for utilization in a remote Local Area Network [WLAN]. The High-Frequency Structure Simulator programming HFSS's optometric is used to make the proposed receiving wire more exact and proficient. Receiving wire plan enhancement is a term used to depict the way toward further developing the radio wire Model of a microstrip line. The HFSS programming was utilized to imitate the technique. This radio wire is made out of FR4 material, and the conditions for roundabout Patch configuration are presented and approved by all-around reproduced results. This radio wire has a 50-ohm input impedance and is based on an FR4 Epoxy dielectric substrate with a general permittivity of 4.4, a thickness of 1.60mm, and an overall permittivity of 4.4. The fundamental design and low profile characteristics of the recommended radio wire simplify it to deliver and are ideal for use in Wi-Fi organizations.

The Integrated Effects of Brivaracetam, a Selective Analog of Levetiracetam, on Ionic Currents and Neuronal Excitability

Brivaracetam (BRV) is recognized as a novel third-generation antiepileptic drug approved for the treatment of epilepsy. Emerging evidence has demonstrated that it has potentially better efficacy and tolerability than its analog, Levetiracetam (LEV). This, however, cannot be explained by their common synaptic vesicle-binding mechanism. Whether BRV can affect different ionic currents and concert these effects to alter neuronal excitability remains unclear. With the aid of patch clamp technology, we found that BRV concentration dependently inhibited the depolarization-induced M-type K+ current (IK(M)), decreased the delayed-rectifier K+ current (IK(DR)), and decreased the hyperpolarization-activated cation current in GH3 neurons. However, it had a concentration-dependent inhibition on voltage-gated Na+ current (INa). Under an inside-out patch configuration, a bath application of BRV increased the open probability of large-conductance Ca2+-activated K+ channels. Furthermore, in mHippoE-14 hippocampal neurons, the whole-cell INa was effectively depressed by BRV. In simulated modeling of hippocampal neurons, BRV was observed to reduce the firing of the action potentials (APs) concurrently with decreases in the AP amplitude. In animal models, BRV ameliorated acute seizures in both OD-1 and lithium-pilocarpine epilepsy models. However, LEV had effects in the latter only. Collectively, our study demonstrated BRV’s multiple ionic mechanism in electrically excitable cells and a potential concerted effect on neuronal excitability and hyperexcitability disorders.

Muskrat distributions in a changing Arctic delta are explained by patch composition and configuration

Climate change is altering Canada’s western Arctic, including hydrology in the heterogeneous environment of the Mackenzie Delta, and these changes are impacting biotic communities. Muskrats are culturally important semi-aquatic rodents whose populations may respond to changing water levels in this region. We investigated the importance of patch configuration and patch composition — two properties affected by climate change — on muskrat presence and distribution in the Mackenzie Delta, using remote sensing and field-based surveys of lakes with and without muskrats. We tested multiple hypotheses about predictors of muskrat and forage biomass presence using a model-selection approach. We found that configuration and patch composition explained muskrat distribution in the Mackenzie Delta, with composition being of greater importance. Muskrats were more likely to occur in lakes with longer perimeters, higher amounts of forage biomass, and sediment characteristics that supported macrophyte growth. The latter two conditions are related to spring flooding regimes, which will likely be altered by climate change. This may result in a decrease in muskrat habitat in the Mackenzie Delta. Our research indicates that both patch composition and configuration are important for understanding species distributions in heterogeneous environments.

Disentangling the Roles of Topography, Patch, and Land Use on Conservation Trait Status of Specialist Birds in Marginal Forest Land Use Types

One of the main questions in ecology and conservation is how organisms are governed and affected by their traits within the context of abiotic gradients. The main question of our study addresses how patch, topography, and land use influence conservation trait status (rarity and red-list index) of birds generally, and of farmland and woodland specialists specifically, in marginal forest landscape types. We sampled birds from 68 traditional fruit orchards existing as remnants of agroforestry within the Pardubice Region of the Czech Republic during two consecutive years. We recorded 57 bird species, of which 31 species were forest dwellers and 16 farmland dwellers. Topographical predictors played the most significant role in influencing traits of the bird community as a whole. Farmland bird traits indicated the most balanced values, as they were significantly influenced by all studied predictor sets. Their responses nevertheless differed among the studied traits and also showed a more complex pattern because the values of interaction between some predictor categories were relatively high. Traits of woodland birds were most influenced by the patch configuration. We found that a structurally diversified marginal habitat type of traditional fruit orchards is able to promote a number of specialist species and also reveals important relationships between bird conservation traits and different predictor sets. Researchers should pay more attention to the conservation traits of birds and their interactions with environmental predictors. Furthermore, conservationists should be more attentive to the biodiversity value and sustainable management of traditional fruit orchards.

Nest site selection and nest survival of Black-backed Woodpeckers after wildfire

Recently burned coniferous forests host wildlife communities that respond to variation in burn severity, post-fire habitat structure, and patch configuration. Habitat selection theory predicts that birds inhabiting these variable post-fire landscapes will select nesting locations that confer an adaptive advantage through increased fitness and reproductive success. Understanding the effect of post-fire habitat on avian nesting ecology can provide valuable information to guide restoration and management after wildfire. The Black-backed Woodpecker (Picoides arcticus) is strongly associated with recently burned forests in the western United States, where it is used as an indicator species for the effects of post-fire forest management. Between 2011 and 2018, we located and monitored 118 Black-backed Woodpecker nests in burned forests of northern California. We evaluated the influence of habitat and nest characteristics on nest site selection and daily nest survival. Our results demonstrate a pattern of neutral congruence between habitat selection and fitness. Black-backed Woodpeckers showed strong selection for each of the nest habitat variables that we measured: woodpeckers selected moderately sized trees in areas of high snag density burned at high severity, but also in areas relatively close to low-severity or unburned edges. However, only nest initiation date affected nest survival, with decreased survival in late-season nests. Our results suggest that management actions aimed at maintaining breeding habitat for Black-backed Woodpeckers should prioritize retention and creation of pyrodiverse landscapes that include dense stands of snags (>5 snags per 100 m2) within ~500 m of forest that burned at low severity or remained unburned.

Non-Central Influences of α2-Adrenergic and Imidazoline Agonist Interactions in Isolated ardiomyocytes Cardiac Cells

Aim: to investigate the functional interaction of α2-adrenergic and imidazoline receptors recently identified on the sarcolemma of isolated cardiomyocytes for regulation of the intracellular calcium and the production of the signal molecule of nitric oxide (NO).Materials and methods:experiments were performed on isolated left ventricular cardiomyocytes of Wistar rats. Potential-dependent Ca2+-currents were measured from the whole-cell by the patch-clamp method in “perforated-patch” configuration. The intracellular calcium and the production of nitric oxide were estimated from the changes in fluorescence intensity of the Ca2+-specific and NO-sensitive dyes at fluorescent or confocal microscope.Results:It has been shown that α2‑adrenergic and imidazoline receptor agonists inhibit L-type Ca2+-currents by themselves, but their effects do not develop against each other’s background. The blockade of key effector molecules: protein kinase B (Akt kinase) for α2‑adrenergic receptors, and protein kinase C for imidazoline receptors causes the action of agonists to become additive. Both the selective α2‑agonist, guanabenz, and the specific agonist of the first type imidazoline receptors, rilmenidine, show an additional inhibition of Ca2+-currents against the basal background already reduced by the activation of one of the two receptor systems. Wherein rilmenidine increases the level of free Ca2+in the cytosol, and guanabenz, on the contrary, decreases it. The action of guanabenz does not develop against the background of rilmenidine, although it, in turn, effectively increases the intracellular level of calcium in guanabenz-pretreated cardiac cells. Activation of α2‑adrenergic receptors leads to significant stimulation of the endothelial isoform of NO-synthase, and as a result to an increase in the NO level. Activation of imidazoline receptors itself does not affect NO synthesis but it prevents the production of NO induced by α2‑agonists.Conclusion:obtained data make it possible to formulate a number of useful recommendations for clinical practice, and also to clarify the non-central peripheral effects arising from the activation of α2‑adrenergic or imidazoline systems under conditions of endogenous hyperactivation on of the two systems.

The effect of some anesthetics and natural venoms on the LCС-channels functioning of the nuclear membrane of cardiomyocytes and cerebellum Purkinje neurons

The investigation of pharmacological sensitivity of the cationic channels in nuclear membrane to the influence of anesthetics and natural venoms is relevant since it was shown that some modulators of N-cholinoreceptors (dithylinum, atracurium) affecting the large conductance cation channels (LCC-channels) functional activity are used in medicine during surgery. In addition, some injectable forms of toxins from the snake venom are used as drugs with an analgesic effect. Therefore, the aim of the study was to investigate the pharmacological sensitivity of the LCC-channels to the muscle relaxants, anaesthetics (mydocalm, diprofol) and natural venoms (neurotoxin II, α-Cobratoxin). The influence of these substances was evaluated based on changes in biophysical parameters of functioning of the LCC-channels of nuclear membrane of the cardiomyocytes and cerebellar Purkinje neurons. Ion currents through these channels were registered in the nucleus-attached or excised patch configuration and the voltage-clamp mode of the patch-clamp technique. We found that mydocalm (2 mM), diprofol (2 mM) and α-Cobratoxin (1 mM) reduced several times the probability of the channels being in the open state. Under the influence of mydocalm and α-Kobratoxin in high concentrations (1-2 mM) the effect of channels flickering was observed which indicates the channel pore blocking in its open state. At the same time, the average amplitude of the K+ current through the LCC-channels decreased by 13 % under the influence of NT II (25 μM). The results will be the basis for identification of new, more effective inhibitors of the LCC-channels that will be promising for the physiological relevance and structure of the channels investigation.