Pairs Of Units Research Articles

Pliocene hyperpycnal flow and its sedimentary pattern in D block of Rakhine Basin in Bay of Bengal

Abstract Based on core, logging, lab test and seismic data, sedimentary characteristics and pattern of marine hyperpycnal flow, the distribution rules of hyperpycnal flow reservoir, prediction method of favorable hyperpycnal flow reservoir zones, hydrocarbon accumulation model in hyperpycnal flow reservoir in D block of Bay of Bengal were investigated, and the favorable exploration zone and well sites were predicted. Pliocene in D block has typical hyperpycnal flow sediment, which is a set of fine-medium sandstone held between thick layers of marine mudstone and features a series of reverse grading unit and normal grading unit pairs. The hyperpycnal flow sediment appears as heavily jagged box shape, bell shape and tongue shape facies on log curves with linear gradient, and corresponds to multiple phases of deep channels on the seismic section and high sinuous channel on stratal slices. The sedimentary bodies formed by a single phase hyperpycnal flow which include five types of microfacies, namely, supply channel (valley), channel complex, branch channel, levee and sheet sand. The hyperpycnal flow sediments appear in multiple branches, multiple generations and stages in space, forming high-quality reservoirs in strips on the plane and superposition vertically, with fairly good physical properties. The channel complex sandstone, with large thickness, coarse particle size and good physical properties, is the most favorable exploration facies. Based on the guidance of the sedimentary model, distribution of the channel complex microfacies was delineated in detail by seismic reflection structure analysis, spectrum waveform characteristic analysis, slice and attribute fusion, and combined with the structural feature analysis, the favorable drilling zone was sorted out, effectively guiding the exploration deployment of the block.

BN‐Embedded Polycyclic Aromatic Hydrocarbon Oligomers: Synthesis, Aromaticity, and Reactivity

AbstractBN‐embedded oligomers with different pairs of BN units were synthesized by electrophilic borylation. Up to four pairs of BN units were incorporated in the large polycyclic aromatic hydrocarbons (PAHs). Their geometric, photophysical, electrochemical, and Lewis acidic properties were investigated by X‐ray crystallography, optical spectroscopy, and cyclic voltammetry. The B−N bonds show delocalized double‐bond characteristics and the conjugation can be extended through the trans‐orientated aromatic azaborine units. Calculations reveal the relatively lower aromaticity for the inner azaborine rings in the BN‐embedded PAH oligomers. The frontier orbitals of the longer oligomers are delocalized over the inner aromatic rings. Consequently, the inner moieties of the BN‐embedded PAH oligomers are more active than the outer parts. This is confirmed by a simple oxidation reaction, which has significant effects on the aromaticity and the intramolecular charge‐transfer interactions.

BN-Embedded Polycyclic Aromatic Hydrocarbon Oligomers: Synthesis, Aromaticity, and Reactivity.

BN-embedded oligomers with different pairs of BN units were synthesized by electrophilic borylation. Up to four pairs of BN units were incorporated in the large polycyclic aromatic hydrocarbons (PAHs). Their geometric, photophysical, electrochemical, and Lewis acidic properties were investigated by X-ray crystallography, optical spectroscopy, and cyclic voltammetry. The B-N bonds show delocalized double-bond characteristics and the conjugation can be extended through the trans-orientated aromatic azaborine units. Calculations reveal the relatively lower aromaticity for the inner azaborine rings in the BN-embedded PAH oligomers. The frontier orbitals of the longer oligomers are delocalized over the inner aromatic rings. Consequently, the inner moieties of the BN-embedded PAH oligomers are more active than the outer parts. This is confirmed by a simple oxidation reaction, which has significant effects on the aromaticity and the intramolecular charge-transfer interactions.

On the use of adaptive spatial weight matrices from disease mapping multivariate analyses

Conditional autoregressive distributions are commonly used to model spatial dependence between nearby geographic units in disease mapping studies. These distributions induce spatial dependence by means of a spatial weights matrix that quantifies the strength of dependence between any two neighboring spatial units. The most common procedure for defining that spatial weights matrix is using an adjacency criterion. In that case, all pairs of spatial units with adjacent borders are given the same weight (typically 1) and the remaining non-adjacent units are assigned a weight of 0. However, assuming all spatial neighbors in a model to be equally influential could be possibly a too rigid or inappropriate assumption. In this paper, we propose several adaptive conditional autoregressive distributions in which the spatial weights for adjacent areas are random variables, and we discuss their use in spatial disease mapping models. We will introduce our proposal in a multivariate context so that the spatial dependence structure between spatial units is shared and estimated from a sufficiently large set of mortality causes. As we will see, this is a key aspect for making inference on the spatial dependence structure. We show that our adaptive modeling proposal provides more flexible and accurate mortality risk estimates than traditional proposals in which spatial weights for neighboring areas are fixed to a common value.

Highly Bright Fluorescence from Dispersed Dimers: Deep‐Red Polymorphs and Wide‐Range Piezochromism

AbstractNear‐infrared piezochromic materials (PCMs), which show a fluorescence response with a clear color difference and strong penetrability, have important potential applications, but few such organic luminophores have been reported. High‐brightness donor (D)–acceptor (A) luminophores present great potential for preparing near‐IR PCMs with clear color differences. However, the intermolecular π–π interactions are sharply enhanced at high pressures, which is not beneficial for the improvement of the piezochromic properties. Herein, two crystalline polymorphs (TPEB‐α and TPEB‐γ) of a D–π–A‐type dye is presented, which emits deep‐red fluorescence with a high emission efficiency (53.2% and 28.1%, respectively). In crystalline state, dispersed dimers are observed and arranged in a herringbone pattern. Interestingly, each dimer is surrounded by four pairs of twisted tetraphenyl ethylene units, which could disrupt the π–π interactions between adjacent dimers during compression. As a result, this luminophor with dispersed dimeric stacking demonstrates the deep‐red to near‐infrared piezochromic behavior with a remarkable redshift (212 nm) and high sensitivity (19.8 nm GPa−1).

Electropermanent magnet blank holder technique in sheet metal deep drawing

A novel blank holder technique based on electropermanent magnet (EPM) technology is proposed, in which independent loading of blank holding force (BHF) can be realized in sheet metal forming process. The magnetic force and the resulting BHF are applied by permanent magnets rather than electromagnets, and the current is only required at the moment of loading or unloading the BHF. The BHF is convenient in control, low in energy consumption, and without overheating problem using this technique. In this paper, an experimental setup consisting of magnetic cushion, die, punch, and other components is designed based on the characteristics of EPM and requirements of deep drawing process. The magnetic cushion including blank holder and magnetic pole units is used to generate magnetic force and realize loading and unloading of BHF. Then, magnetic field analyses of a pair of magnetic pole units and the designed cushion are carried out by FEM. Also, the coupling problem involving magnetic field and stress field is further analyzed and solved by means of theoretical method and FEM, and the BHF and the blank holding pressure on the sheet using the new technique can be obtained. The deformation of the designed setup is small, and the stiffness can satisfy the requirements. The deep drawing processes of cylindrical cup of 08Al sheet with 0.98 mm thickness are simulated by using conventional blank holder and the new technique, respectively, and there are small differences of the strain distributions of the drawn parts with the two techniques. The experiments of cylindrical cup deep drawing applied four different BHFs, respectively, are carried out using EPM bank holder technique. The results indicate that the BHF applied by the designed cushion is large enough for the deep drawing process of the selected sheet.

Impact of parameter selection on estimates of motoneuron excitability using paired motor unit analysis

Objective. Noninvasive estimation of motoneuron excitability in human motoneurons is achieved through a paired motor unit analysis (ΔF) that quantifies hysteresis in the instantaneous firing rates at motor unit recruitment and de-recruitment. The ΔF technique provides insight into the magnitude of neuromodulatory synaptic input and persistent inward currents (PICs). While the ΔF technique is commonly used for estimating motoneuron excitability during voluntary contractions, computational parameters used for the technique vary across studies. A systematic investigation into the relationship between these parameters and ΔF values is necessary. Approach. We assessed the sensitivity of the ΔF technique with several criteria commonly used in selecting motor unit pairs for analysis and methods used for smoothing the instantaneous motor unit firing rates. Using high-density surface EMG and convolutive blind source separation, we obtained a large number of motor unit pairs (5409) from the triceps brachii of ten healthy individuals during triangular isometric contractions. Main results. We found an exponential plateau relationship between ΔF and the recruitment time difference between the motor unit pairs and an exponential decay relationship between ΔF and the de-recruitment time difference between the motor unit pairs, with the plateaus occurring at approximately 1 s and 1.5 s, respectively. Reduction or removal of the minimum threshold for rate–rate correlation of the two units did not affect ΔF values or variance. Removing motor unit pairs in which the firing rate of the control unit was saturated had no significant effect on ΔF. Smoothing the filter selection had no substantial effect on ΔF values and ΔF variance; however, filter selection affected the minimum recruitment and de-recruitment time differences. Significance. Our results offer recommendations for standardized parameters for the ΔF approach and facilitate the interpretation of findings from studies that implement the ΔF analysis but use different computational parameters.

Optimal Membrane-Process Design (OMPD): A software product for optimal design of membrane gas separation processes

The optimal design of a membrane gas separation process requires minimizing several objective functions subject to nonlinear relationships among the optimizing variables. This article describes a novel software product, named Optimal Membrane-Process Design (OMPD), for the optimal design of membrane gas separation processes. The product generates several potential process design configurations and then searches the process design parameters and operating conditions spaces to arrive at optimal design specifications and operating conditions. It is able to consider every type and any number of operational, compositional, and economical objective functions in a computationally cost-effective manner. It calculates all Pareto optimal solutions in a single trial. It can optimize any number of membrane units arranged in multi-step and/or multi-stage configurations. It optimally places pairs of adjacent membrane units, either two-step or two-stage, while simultaneously considering several membrane types.

Passive muscle stretching reduces estimates of persistent inward current strength in soleus motor units.

Prolonged (≥60 s) passive muscle stretching acutely reduces maximal force production at least partly through a suppression of efferent neural drive. The origin of this neural suppression has not been determined; however, some evidence suggests that reductions in the amplitude of persistent inward currents (PICs) in the motoneurons may be important. The aim of the present study was to determine whether acute passive (static) muscle stretching affects PIC strength in gastrocnemius medialis (GM) and soleus (SOL) motor units. We calculated the difference in instantaneous discharge rates at recruitment and de-recruitment (ΔF) for pairs of motor units in GM and SOL during triangular isometric plantar flexor contractions (20% maximum) both before and immediately after a 5min control period and immediately after five 1min passive plantar flexor stretches. After stretching, there was a significant reduction in SOL ΔF (-25.6%; 95% confidence interval, CI=-45.1% to -9.1%, P=0.002) but not GM ΔF These data suggest passive muscle stretching can reduce the intrinsic excitability, via PICs, of SOL motor units. These findings (1) suggest that PIC strength might be reduced after passive stretching, (2) are consistent with previously established post-stretch decreases in SOL but not GM EMG amplitude during contraction, and (3) indicate that reductions in PIC strength could underpin the stretch-induced force loss.

Long-Term Hypoxic/Hypocapnic Storage of Red Blood Cells Results in Amelioration of Lesion Hallmarks and Increased In Vivorecovery at 24 Hours Post-Transfusion

Oxidative damage, dysmetabolism and decreased levels of 2, 3-diphosphoglycerate (2,3-DPG) affect red blood cell (RBC) survival and the affinity of Hemoglobin for oxygen are relevant hallmarks of RBC storage lesion, especially in specific clinical contexts. We hypothesized that oxygen and carbon dioxide reduction followed by hypoxic/hypocapnic storage would result in amelioration of RBC lesion assessed at the end of their shelf-life and at the shelf-life mode (21 days).To determine the relevance of hypoxic/hypocapnic storage in humans, a pivotal, prospective, randomized, two‐arm, crossover, three‐center trial was conducted to evaluate [Hemanext®] hypoxic/hypocapnic processing system and was used to assess whether this process and storage method met standard FDA acceptability criteria for long-term RBC storage. The Test arm consisted of whole blood (WB)‐derived, leukoreduced RBC in AS-3 additive processed at room temperature with the Hemanext system for 3 hours to achieve hypoxic/hypocapnic state within 12 hours of phlebotomy which was maintained hypoxic during storage for up to 43 days at 1‐6°C (Test).Unprocessed units (Control) were stored within 8 hours under conventional storage conditions. Subjects (N=100) donated CP2D WB (500 ± 50 mL) and a minimum of 93 pairs of RBC units per arm were analyzed for in vitroquality parameters. For in vivo analysis at end of storage, RBCs from 19 test subjects and 21 control subjects (14 paired) from two sites were radiolabeled with 51‐Cr/99‐Tc(m), autologously transfused, and analyzed for 24-hour recovery. Differences between the Test and Control groups were analyzed using the paired t-test (Wilcoxon test where necessary). Paired analyses of 24-hour in vivorecoveries on day 43 was 89.3±4.5% and 84.8±6.2% for the test and control, respectively; p<0.01). Significantly higher levels of 2,3-DPG and adenosine 5'-triphosphate (ATP) were maintained for the Test group by days 21 and 42/43 of storage (Table 1). Percentage of hemolysis was similar in both groups. In summary, these data demonstrate that RBCs preserved in a user-friendly, self-contained hypoxic storage system are superior than the conventionally stored RBCs and may provide more viable RBCs for transfusion at 6 weeks of storage. Disclaimer: The51‐Cr/99‐Tc(m)labeling at one of the three sites occurred without prior RDRC approval and did not meet GMP standards. Disclosures Cancelas: Fresenius-Kabi: Research Funding; Cerus Co.: Research Funding; TerumoBCT: Consultancy, Research Funding; Hemanext: Consultancy, Research Funding; Macopharma Inc: Research Funding; Cytosorbents: Research Funding; Cellphire: Research Funding; Velico: Consultancy, Research Funding. Yoshida:New Health Sciences Inc.: Employment, Equity Ownership. Dioguardi:Hemanext: Employment. Iselin:Hemanext: Employment. Dunham:Hemanext: Employment.

Balanced sampling plans excluding adjacent units for linear ordering of population units

Balanced sampling plans excluding adjacent units or BSA (α) plans are useful where any pair of units which are separated by a distance of α units are called adjacent units and the adjacent pairs of units never appear together in a sample in the plan. In BSA (α) plans, first order inclusion probabilities are constant and second order inclusion probabilities are zero for pairs of adjacent units and constant for all other pairs of units. In this article, we present 66 new balanced sampling plans excluding adjacent units for one dimensional population linear ordering of units in the parametric range N ≤ 60, n ≤ 7, λ ≤ 10, α ≤ 7. An algorithm based on linear integer programming is used for development of these plans.

Bilingual lexical extraction based on word alignment for improving corpus search

Purpose This paper aims to describe the structure of an aligned Serbian-German literary corpus (SrpNemKor) contained in a digital library Bibliša. The goal of the research was to create a benchmark Serbian-German annotated corpus searchable with various query expansions. Design/methodology/approach The presented research is particularly focused on the enhancement of bilingual search queries in a full-text search of aligned SrpNemKor collection. The enhancement is based on using existing lexical resources such as Serbian morphological electronic dictionaries and the bilingual lexical database Termi. Findings For the purpose of this research, the lexical database Termi is enriched with a bilingual list of German-Serbian translated pairs of lexical units. The list of correct translation pairs was extracted from SrpNemKor, evaluated and integrated into Termi. Also, Serbian morphological e-dictionaries are updated with new entries extracted from the Serbian part of the corpus. Originality/value A bilingual search of SrpNemKor in Bibliša is available within the user-friendly platform. The enriched database Termi enables semantic enhancement and refinement of user’s search query based on synonyms both in Serbian and German at a very high level. Serbian morphological e-dictionaries facilitate the morphological expansion of search queries in Serbian, thereby enabling the analysis of concepts and concept structures by identifying terms assigned to the concept, and by establishing relations between terms in Serbian and German which makes Bibliša a valuable Web tool that can support research and analysis of SrpNemKor.

Rank-one basis made from matrix-product states for a low-rank approximation of molecular aggregates.

An efficient low-rank approximation to complete active space (CAS) wavefunctions for molecular aggregates is presented. Molecular aggregates usually involve two different characteristic entanglement structures: strong intramolecular entanglement and weak intermolecular entanglement. In the method, low-lying electronic states of molecular aggregates are efficiently expanded by a small number of rank-one basis states that are direct products of monomolecular wavefunctions, each of which is written as a highly entangled state such as the matrix product state (MPS). The complexities raised by strong intramolecular entanglement are therefore encapsulated by the MPS and eliminated from the degree of freedom of the effective Hamiltonian of molecular aggregates. It is demonstrated that the excitation energies of low-lying excited states of a pair of bacteriochlorophyll units with CAS(52e, 50o) are accurately reproduced by only five rank-one basis states. Because the rank-one basis states naturally have diabatic character and reproduce the low-lying spectrum of the CAS space, off-diagonal elements of the Hamiltonian are expected to give accurate diabatic couplings. It is also demonstrated that the energy splitting and the diabatic couplings in anthracene dimer systems are improved by augmenting with additional rank-one basis states.

Convolutional relation network for skeleton-based action recognition

In the skeleton-based action recognition, mining information from the joints and limbs of human skeletons plays a key role. Previous studies treated the skeleton data as vectors and could not explicitly capture the joint interactions (e.g., RNN-based methods), or modeled the joint interactions in a local manner and may lose important cues without global response mapping (e.g., CNN and GCN (Graph Convolution Network) based methods). In this work, we address these problems by considering the potential relations of all the node pairs and edge pairs on the skeleton graphs. A dilation group-specific convolution module is proposed to aggregate relation messages of all the unit pairs on the skeleton graphs. By enumerating all the pair relations, the joint interactions could be learned explicitly and globally. It is then enhanced by introducing the attention pooling including temporal attention, spatial attention and channel attention. By stacking such several blocks, the relation messages of the node pairs are augmented by multi-layer propagation. Finally, the late fusion of four streams is used to combine the predictions of different inputs including node pairs, edge pairs and corresponding frame differences. The proposed method, termed conv-relation network, achieves competitive performance on two large scale datasets, NTU RGB+D and Kinetics.

Single-motor-unit discharge characteristics in lumbar multifidus muscle of acute low back pain patients

Acute low back pain (ALBP) causes rapid deterioration of paraspinal muscle function. The underlying neurophysiology is poorly understood. We therefore carried out this observational study in patients with ALBP to characterize motor unit (MU) activity in deep lumbar multifidus (LM) muscle and compare with our previous findings from pain-free subjects. Nine subjects (1 woman; age 26-59 yr) with ALBP duration of 1-21 days were recruited from outpatient clinics. Fine wire electromyography (EMG) electrodes were implanted bilaterally at the painful spinal level under computer tomography guidance. EMG was recorded during spontaneous sitting and standing, and during voluntary force production. Linear mixed models were utilized to test or control for the effects of a number of predefined variables. Compared with sitting, standing increased total duration of EMG activity, median MU discharge rate, interspike interval variability, and common drive measured as common drive coefficients (CDC) derived from concurrently active MU pairs. Median discharge rate in 73 MUs was 5.5 and 6.6 pulses per second (pps) during spontaneous sitting and standing, and 7.2 pps during voluntary force production. Interspike interval variability was lower during voluntary tasks than during spontaneous force production. Common drive was less pronounced in bilateral vs. unilateral unit pairs, also in spontaneous standing. This difference was not seen in our previous pain-free subjects, suggesting altered bilateral control of the spine in ALBP. The distribution of CDC values was not a homogeneous continuum but could be seen as two partially overlapping populations of CDC distributions.NEW & NOTEWORTHY We implanted fine-wire electrodes in the deepest part of axial postural muscles in patients with acute low back pain and characterized their motor unit activity. We found less pronounced common drive to the two sides of the spine compared with pain-free subjects, suggesting a different postural control strategy in patients with acute low back pain. An unexpected finding was that common drive coefficient values appeared to consist of two partially overlapping populations of normal distributions.

Evaluation of Spike Sorting Algorithms: Application to Human Subthalamic Nucleus Recordings and Simulations

An important prerequisite for the analysis of spike synchrony in extracellular recordings is the extraction of single-unit activity from the multi-unit signal. To identify single units, potential spikes are separated with respect to their potential neuronal origins (‘spike sorting’). However, different sorting algorithms yield inconsistent unit assignments, which seriously influences subsequent spike train analyses. We aim to identify the best sorting algorithm for subthalamic nucleus recordings of patients with Parkinson's disease (experimental data ED). Therefore, we apply various prevalent algorithms offered by the ‘Plexon Offline Sorter’ and evaluate the sorting results. Since this evaluation leaves us unsure about the best algorithm, we apply all methods again to artificial data (AD) with known ground truth. AD consists of pairs of single units with different shape similarity embedded in the background noise of the ED. The sorting evaluation depicts a significant influence of the respective methods on the single unit assignments. We find a high variability in the sortings obtained by different algorithms that increases with single units shape similarity. We also find significant differences in the resulting firing characteristics. We conclude that Valley-Seeking algorithms produce the most accurate result if the exclusion of artifacts as unsorted events is important. If the latter is less important (‘clean’ data) the K-Means algorithm is a better option. Our results strongly argue for the need of standardized validation procedures based on ground truth data. The recipe suggested here is simple enough to become a standard procedure.

Crystal structure and pseudosymmetry analysis of the triclinic prodrug cloxazolam (Z′ = 4)

The prodrug cloxazolam [systematic name: 13-chloro-2-(2-chlorophenyl)-3-oxa-6,9-diazatricyclo[8.4.0.02,6]tetradeca-1(10),11,13-trien-8-one], C17H14Cl2N2O2, crystallizes in the triclinic space group P-1, with four chemically identical independent molecules in the asymmetric unit. However, in order to facilitate the analysis of the striking pseudosymmetry relating the four independent molecules, the structure has been analysed and reported in the nonconventional centred B-1 space-group setting. Pseudosymmetry is an eminently local property, valid only in the realm of the unit-cell boundary and not propagating to the whole crystal structure. It has been analyzed using the MP procedure described in the preceding article [Baggio (2019). Acta Cryst. C75, 837-850]. The molecules consist of a rigid core made up of three rings (five-, six- and seven-membered) and an extra six-membered ring joined to the latter group by a single C-C bond, together with a clamping intramolecular C-H...O interaction preventing free rotation and providing additional rigidity. The four molecules in the asymmetric unit pair into dimers with almost exact twofold pseudosymmetry, further linked into (001) slabs as the building bricks of the structure. Interpenetration of slabs finally leads to a three-dimensional structure of unusual compactness for an organic structure, with a Kitaigorodskii packing index of ca 0.71.

B2 N2 -Embedded Polycyclic Aromatic Hydrocarbons with Furan and Thiophene Derivatives Functionalized in Crossed Directions.

A series of polycyclic aromatic hydrocarbons (PAHs), consisting of two pairs of BN units, have been designed and their synthesis has been achieved by electrophilic C-H borylation. Two conjugation extension directions can be found in these B2 N2 -embedded PAHs. The B2 N2 -containing backbone with shorter effective conjugation length is isoelectronic with diaryl-fused anthracene, whereas the second derivative, with longer effective conjugation length, is isoelectronic with bis(trans-arylvinyl)benzene. By incorporating different aryl groups, i.e., furyl, thienyl, benzo[b]furyl, and benzo[b]thienyl groups, into the two crossed directions of the B2 N2 -embedded PAHs, their electronic and optical properties have been comparatively investigated by photophysical, electrochemical, and theoretical approaches. It is found that both the substituents and their conjugation extension directions have significant effects on the aromatic and photophysical properties of the B2 N2 -embedded PAHs. The conjugation extension in the shorter backbone is more pronounced on the effective conjugation length than the longer backbone. Moreover, all the B2 N2 -embedded PAHs behave as both Lewis acids and Lewis bases, and reversible photoluminescence switching can be observed by simply neutralizing the added Lewis acid or Lewis base.

An assessment of sperm whale occurrence and social structure off São Miguel Island, Azores using fluke and dorsal identification photographs

AbstractFemale and immature sperm whales form stable social units in tropical to subtropical waters. One such area is the Azores archipelago, where details of their year‐round occurrence and social organization are not well known. We used year‐round sightings data collected from whale watching vessels to assess sperm whale occurrence and social structure off São Miguel Island, Azores from 2010 to 2017. Individuals were photo‐identified by their flukes (n = 393) and dorsal pigmentation marks were examined to explore their use in assisting with reidentifications. Of all cataloged whales, 78.8% were sufficiently distinctive to be reidentified from dorsal pigmentation patterns. Associations between individuals were analyzed to determine social structure and delineate social units. We identified 12 units comprising 2–13 members that had stable, and perhaps preferred associations for periods up to the eight years of the study. Preferences between some pairs of units may exist, but more research is required to better understand dynamics within and between units. This local scale study is an important contributor to our knowledge of geographic variation on a global scale. We recommend making use of all available information from the entire archipelago, to further increase our understanding of sperm social organization in the Azores.

The Influence on the Q Value of the THz Metasurface From the Tip Charge Accumulation Coupling

With the adventure of metamaterials, there has been a tremendous advancement in the manipulation of the terahertz (THz) wave. However, the excitation of high- Q -factor resonance has been a great challenge in traditional metamaterials due to ohmic and radiation losses. In this paper, the influence of the tip charge accumulation effect on the high- Q -value metasurface has been studied within the triangular array metasurface. It is found that when the tip charges accumulation resonance from each pair of triangular units can couple with each other to construct a significant resonant mode which could trap more energy to achieve higher Q value. Moreover, the stacking of the induced charges distributed at the surface of the metaunit making the coupling strength is further increased so that the strong tip charge accumulation effect could also affect the Q value. The experiment verified this phenomenon, which shows the stronger coupling resonance, and tip charge accumulation could result in the enhancement of the Q value. This research has potential applications in high- Q THz devices.