Trapping Potential Research Articles

Snapshot of the Atlantic Forest canopy: surveying arboreal mammals in a biodiversity hotspot

AbstractThe Atlantic Forest of South America supports a rich terrestrial biodiversity but has been reduced to only a small extent of its original forest cover. It hosts a large number of endemic mammalian species but our knowledge of arboreal mammal ecology and conservation has been limited because of the challenges of observing arboreal species from ground level. Camera trapping has proven to be an effective tool in terrestrial mammal monitoring but the technique has rarely been used for arboreal species. For the first time in the Atlantic Forest, we obtained data on the arboreal mammal community using arboreal camera trapping, focusing on Caparaó National Park, Brazil. We placed 24 infrared camera traps in the forest canopy in seven areas within the Park, operating them continuously during January 2017–June 2019. During this period the camera traps accumulated 4,736 camera-days of footage and generated a total of 2,256 photographs and 30-s videos of vertebrates. The arboreal camera traps were able to detect arboreal mammals of a range of body sizes. The mammal assemblage comprised 15 identifiable species, including the Critically Endangered northern muriqui Brachyteles hypoxanthus and buffy-headed marmoset Callithrix flaviceps as well as other rare, nocturnal and inconspicuous species. We confirmed for the first time the occurrence of the thin-spined porcupine Chaetomys subspinosus in the Park. Species richness varied across survey areas and forest types. Our findings demonstrate the potential of arboreal camera trapping to inform conservation strategies.

Preferences of Lygus pratensis (Hemiptera: Miridae) for Four Potential Trap Crop Plants

Abstract The mirid, Lygus pratensis (L.) (Hemiptera: Miridae), is a major pest of cotton (Gossypium spp.) in Xinjiang Uyghur Autonomous Region, China. In this study, we aimed to reveal the preferences of L. pratensis toward four potential trap crop plants for use in controlling this pest. The population densities of L. pratensis on five host plants were investigated by visual observation, and the behavioral responses of L. pratensis to the five host plants were determined by Y-type olfactory assays and laboratory selectivity assays. The results showed significant differences in host preferences in the field. The average numbers of adults on the five host plants are in the following order, from high to low: Lepidium latifolium (L.), Kochia prostrata (L.) Schrad, Chenopodium glaucum (L.), Medicago sativa (L.), and Gossypium spp. Laboratory selectivity assays found that K. prostrata had the highest number of adults at 5 min, but L. latifolium had the highest number of adults from 1.5 to 4.5 h. The Y-tube olfactometer assays found no significant evidence for selection of L. pratensis between the volatiles of M. sativa and pure air, but did for the other four plants. In conclusion, the blooming stage of L. latifolium was the most attractive to L. pratensis in the field and is, thus, a potential trap crop plant for L. pratensis.

Quantum sensing with sub-Planck structures for the dynamics of Bose-Einstein condensate in presence of engineered potential barriers inside a harmonic trap

We report a scheme for quantum sensing in ultracold atoms by utilizing an atom-interferometer producing sub-Planck scale structures. The condensate is trapped in a hybrid potential, comprising of an overall harmonic trap and sharp potential barriers which are designed as 50-50 atomic beam-splitters. A scaling law for quantum sensing is established for ultracold atoms and the maximum limit of quantum sensing is identified. Quantum sensing for position, momentum and temperature are demonstrated with a sufficiently stable condensate. The present scheme reveals maximum limit of quantum sensitivity for ultracold atoms against infinitesimal external perturbations. With a designable time sequence for the trapping potential, our results provide a promising scheme for quantum sensing with Bose-Einstein condensate in atomic chips.

Spectroscopic X-ray imaging at MHz frame rates — the HEXITECMHz ASIC

The HEXITECMHz ASIC has been developed for the HEXITECMHz Detector System, to deliver spectroscopic x-ray imaging at frame rates up to 1 MHz for future high-flux-rate applications. Optimised for sensing electron signals from detector materials such as CdTe, CdZnTe, GaAs and p-type silicon detectors, the design has an array of 80 × 80 pixels on a pitch of 250 μm, with each pixel capable of measuring single x-ray photons up to energies of 300 keV, with a resolution of 1 keV FWHM. The induced charge signals that are measured by the ASIC will typically be due to the drift of electrons in the sensor material. However, each pixel is also capable of measuring signals of the opposite polarity with magnitudes of up to 20 keV. These events are induced by weighting potential crosstalk and trapping in the sensor and can be exploited in order to provide further improvements in the spatial and spectroscopic performance of the detector. The signals from pixels are digitized every 1 μs by 12-bit time-to-digital converters. This gives a maximum of 107 photons s−1 mm−2 that can be measured. However, for spectroscopic imaging the occupancy should be limited to 10% in each frame to reduce the charge sharing events. This gives a count rate limit of 106 photons s−1 mm−2 which is two orders of magnitude greater than the previous HEXITEC ASICs. To save power, each converter is shared between groups of eight pixels. Each 76.8 kbit data frame is Aurora 64b/66b encoded and serialised over 20 lanes of differential CML, all operating in parallel at 4.1 Gbps. The ASIC can free run with an asynchronous source or can be synchronized with a pulsed source using the SYNC control input. Expected power consumption is 12–15 W from a 1.8 V supply.

Asymmetric vortex dynamics in two-dimensional Bose–Einstein condensate with harmonic trap potential

Based on the two-dimensional Gross–Pitaevskii equation model, we investigated the asymmetric vortex evolution of two-dimensional Bose–Einstein condensates in a harmonic potential trap with polar direction perturbation. This corresponds to the generation of an asymmetric vortex evolution mode under initial vortex light manipulation together with polar direction perturbation. Unlike most of the prior work on this topic that uses a pure numerical method for the system under study, we use an exact analytical method rather than numerical simulation to investigate the key features of the system evolution dynamics in this study. Based on the variational method, and for different system parameter settings including the strength of the harmonic oscillator potential and the nonlinear interaction, we derived two evolution modes, namely, the periodic evolution oscillation mode and the monotonic decay mode, and pictorially demonstrated the evolution patterns of the system. In addition, we investigated the scenario when the system is in the rotating state, which corresponds to the action of the quadratic centrifugal potential. Notably, we also identified the damping effects for the two modes with increasing angular velocity, whose upper limit value corresponds to the constant vortex pattern of the system. Our theoretical results can be used to guide the experimental investigation of asymmetric vortex evolution in two-dimensional Bose–Einstein condensates.

An ultrafast electrochemical synthesis of Au@Ag core-shell nanoflowers as a SERS substrate for thiram detection in milk and juice

An innovative bimetallic gold-silver core–shell nanoflowers (Au@Ag-CSNFs) SERS substrate has been synthesized by a facile electrochemical reduction process on an indium tin oxide (ITO) glass with a total fabrication time of 3 min. The proposed Au@Ag-CSNFs SERS substrate has been distributed evenly with numerous interstices and cavities between each branch, suggesting potential target trap sites and “hot spots”. The Au@Ag-CSNFs administered good reproducibility of SERS signals collected from 140 random spots with a relative standard deviation and an enhancement factor of 13.62 % and 0.9 × 107, respectively. The substrate was further extended for the label-free SERS sensing of thiram residues with an ultra-low detection limit of 7.088 × 10-8 mol/L. The designed probe was further subjected to thiram determination in real milk and juice samples with satisfactory recoveries (91.76–109.40 %). The rapidly synthesized Au@Ag-CSNFs substrate can be extended for SERS sensing in a variety of hazards in food settings.

Advancing 3D shaping of vectorial light by counter-propagation of self-healing scalar and vector Bessel–Gaussian beams

It is well known that counter-propagation of structured light fields allows shaping of three-dimensional (3D) structures in amplitude, phase, or polarization. Here, we numerically demonstrate the potential of implementing non-diffracting Bessel–Gaussian (BG) beams for advancing this approach by taking advantage of its characteristic propagation behavior. In this context, we investigate the self-healing property in this counter-propagating configuration, observing a spin angular momentum (SAM) variation and the formation of a continuous orbital angular momentum (OAM) gradient in longitudinal direction. Additionally, by counter-propagation of BG beams of different types, namely, scalar and vector BG beams, we are able to increase the complexity of accessible 3D structured fields, revealing combined amplitude, phase, and polarization modulation in all spatial dimensions. Thereby, the SAM and OAM of the input light fields can be used to design the resulting 3D structure and its angular momenta. The presented light fields open new possibilities for customized optical trapping potentials and allow new insights into fundamental spin–orbit interaction in counter-propagating superpositions of structured fields.

An Evaluation of Snail Immobilization and Mortality Effects Using Selected Chemical Treatments for Potential Trapping Apparatuses

This study evaluated the immobilization and mortality effects of selected wet and dry chemical treatments on the giant African snail. The chemical treatments used were 5 g and 10 g respectively of sodium chloride, calcium hydroxide and copper sulphate. Distilled water was used as a control in the wet phase evaluation of the study. In the first phase, each treatment was dissolved in 1000 ml of water. A total of ten (10) snails were submerged into each treatment and this was replicated ten (10) times. In the second phase of the study, 5 g and 10 g respectively of each dry treatment was evenly sprinkled over ten (10) snails within a confined area. This was replicated ten (10) times. It was concluded that the submergence effects of the wet treatment resulted in 100 percent immobilization and mortality for both the calcium hydroxide and copper sulphate treatment at six (6) hours post submergence. The dry treatments had no effect on immobilization and mortality up to six (6) hours post treatment. There was no treatment effect of sodium chloride for both the wet and dry treatments. The study concludes that low cost solutions such as calcium hydroxide can have an effect on the immobilization of the giant African snail. This finding can enable the development of trap designs which could eliminate the one-way door design and enable multiple entrances. Although both calcium hydroxide and copper sulphate solutions were effective for the immobilization and death of the snails, calcium hydroxide is the recommended option given its low toxicological profile when compared to copper sulphate.

On the existence and limit behavior of ground states for two coupled Hartree equations

We study the ground states for a system of two coupled Hartree equations with both attractive intraspecies and attractive interspecies interactions in RN (N≥3), which can also be described by L2-constraint minimizers of mass critical Hartree energy functionals with trapping potentials. The existence and nonexistence of minimizers are classified completely by establishing the refined Gagliardo-Nirenberg type inequality. Based on some delicate estimates of the Hartree energy functional, the limit behavior of minimizers is also analyzed as the interspecies interaction strength goes to a critical value, where each component of minimizers blows up and concentrates at a flattest common minimum point of trapping potentials. An optimal blow-up rate of minimizers for the Hartree energy functional is concomitantly obtained.

When to stop searching in a highly uncertain world? A theoretical and experimental investigation of “two-way” sequential search tasks

When to stop exploring is crucial in contexts where learning to manage time and uncertainty is critical for carrying out successful initiatives (e.g., innovation, personnel recruitment, vaccine discovery). We investigate analytically and experimentally the exploration-exploitation trade-offs in such contexts. A “two-way” sequential search task is proposed, where the classical exploration-exploitation trade-off in sequential decisions with finite-horizon is coupled with a further one about discovering the real value of each alternative. The longer the time spent on a specific alternative, the higher the certainty about its expected value but at the higher cost of an under-exploitation of the best alternative so far explored. People learn better when to stop the more certain the information is. A potential behavioral trap in the exploration of “two-way” search tasks is identified that brings towards local optima. We recommend policies that induce people to reduce the time spent exploring the alternatives.

Detection of DC electric forces with zeptonewton sensitivity by single-ion phonon laser

Detecting extremely small forces helps exploring new physics quantitatively. Here we demonstrate that the phonon laser made of a single trapped 40Ca+ ion behaves as an exquisite sensor for small force measurement. We report our successful detection of small electric forces regarding the DC trapping potential with sensitivity of (2.41 ±0.49) \({\rm{zN}}/\sqrt {{\rm{Hz}}}\), with the ion only under Doppler cooling, based on the injection-locking of the oscillation phase of the phonon laser in addition to the classical squeezing applied to suppress the measurement uncertainty. We anticipate that such a single-ion sensor would reach a much better force detection sensitivity in the future once the trapping system is further improved and the fluorescence collection efficiency is further enhanced.

Proposal for low-power atom trapping on a GaN-on-sapphire chip

The hybrid photon-atom integrated circuits, which include photonic microcavities and trapped single neutral atom in their evanescent field, are of great potential for quantum information processing. In this platform, the atoms provide the single-photon nonlinearity and long-lived memory, which are complementary to the excellent passive photonics devices in conventional quantum photonic circuits. In this work, we propose a stable platform for realizing the hybrid photon-atom circuits based on an unsuspended photonic chip. By introducing high-order modes in the microring, a feasible evanescent-field trap potential well $\sim0.3\,\mathrm{mK}$ could be obtained by only $10\,\mathrm{mW}$-level power in the cavity, compared with $100\,\mathrm{mW}$-level power required in the scheme based on fundamental modes. Based on our scheme, stable single atom trapping with relatively low laser power is feasible for future studies on high-fidelity quantum gates, single-photon sources, as well as many-body quantum physics based on a controllable atom array in a microcavity.

On Selection of Standing Wave at Small Energy in the 1D Cubic Schrödinger Equation with a Trapping Potential

Combining virial inequalities by Kowalczyk, Martel and Munoz and Kowalczyk, Martel, Munoz and Van Den Bosch with our theory on how to derive nonlinear induced dissipation on discrete modes, and in particular the notion of Refined Profile, we show how to extend the theory by Kowalczyk, Martel, Munoz and Van Den Bosch to the case when there is a large number of discrete modes in the cubic NLS with a trapping potential which is associated to a repulsive potential by a series of Darboux transformations. Even though, by its non translation invariance, our model avoids some of the difficulties related to the effect that translation has on virial inequalities of the kink stability problem for wave equations, it still is a classical model and it retains some of the main difficulties.

Confinement free energy for a polymer chain: Corrections to scaling.

Spatial confinement of a polymer chain results in a reduction of conformational entropy. For confinement of a flexible N-mer chain in a planar slit or cylindrical pore (confining dimension D), a blob model analysis predicts the asymptotic scaling behavior ΔF/N ∼ D-γ with γ ≈ 1.70, where ΔF is the free energy increase due to confinement. Here, we extend this scaling analysis to include the variation of local monomer density upon confinement giving ΔF/N ∼ D-γ(1 - h(N, D)), where the correction-to-scaling term has the form h ∼ Dy/NΔ with exponents y = 3 - γ ≈ 1.30 and Δ = 3/γ - 1 ≈ 0.76. To test these scaling predictions, we carry out Wang-Landau simulations of confined and unconfined tangent-hard-sphere chains (bead diameter σ) in the presence of a square-well trapping potential. The fully trapped chain provides a common reference state, allowing for an absolute determination of the confinement free energy. Our simulation results for 32 ≤ N ≤ 1024 and 3 ≤ D/σ ≤ 14 are well-described by the extended scaling relation giving exponents of γ = 1.69(1), y = 1.25(2), and Δ = 0.75(6).

Revealing the charge transfer mechanism in magnetically recyclable ternary g-C3N4/BiOBr/Fe3O4 nanocomposite for efficient photocatalytic degradation of tetracycline antibiotics.

Pharmaceutical compounds in water bodies pose hazards to the ecosystem because of their biotoxicity potency. To eradicate such pharmaceutical compounds, a novel g-CN/BiOBr/Fe3O4 nanocomposites was prepared using a simplistic route and appraised for photodegradation of model tetracycline antibiotics. The g-CN/BiOBr/Fe3O4 nanocomposites exhibited complete tetracycline degradation in just 60min exposure of simulated light irradiation, which is 6 times higher than the g-CN. Under the analogous condition, the tetracycline mineralization ability of the g-CN/BiOBr/Fe3O4 nanocomposites was evaluated to be 78% of total organic carbon removal. The superior photocatalytic performance is ascribed to the extended visible light harvesting ability and enhanced charge carrier separation/transfer with impeded recombination rate in light of effective indirect Z-scheme heterojunction construction. Based on band-edge potential and radical trapping studies indicate that h+>•O2->•OH are the active species responsible for photodegradation. Furthermore, the ternary nanocomposites are magnetically retrievable and recyclable while retaining their stable photocatalytic performance. This work endows a new perspective on the rational design and construction of magnetically recoverable ternary nanocomposite for environmental remediation.

Active impedance matching of a cryogenic radio frequency resonator for ion traps.

A combination of direct current (DC) fields and high amplitude radio frequency (RF) fields is necessary to trap ions in a Paul trap. Such high electric RF fields are usually reached with the help of a resonator in close proximity to the ion trap. Ion trap based quantum computers profit from good vacuum conditions and low heating rates that cryogenic environments provide. However, an impedance matching network between the resonator and its RF source is necessary, as an unmatched resonator would require higher input power due to power reflection. The reflected power would not contribute to the RF trapping potential, and the losses in the cable induce additional heat into the system. The electrical properties of the matching network components change during cooling, and a cryogenic setup usually prohibits physical access to integrated components while the experiment is running. This circumstance leads to either several cooling cycles to improve the matching at cryogenic temperatures or the operation of poorly matched resonators. In this work, we demonstrate an RF resonator that is actively matched to the wave impedance of coaxial cables and the signal source. The active part of the matching circuit consists of a varactor diode array. Its capacitance depends on the DC voltage applied from outside the cryostat. We present measurements of the power reflection, the Q-factor, and higher harmonic signals resulting from the nonlinearity of the varactor diodes. The RF resonator is tested in a cryostat at room temperature and cryogenic temperatures, down to 4.3K. A superior impedance matching for different ion traps can be achieved with this type of resonator.

ERO1 alpha deficiency impairs angiogenesis by increasing N-glycosylation of a proangiogenic VEGFA

N-glycosylation and disulfide bond formation are two essential steps in protein folding that occur in the endoplasmic reticulum (ER) and reciprocally influence each other. Here, to analyze crosstalk between N-glycosylation and oxidation, we investigated how the protein disulfide oxidase ERO1-alpha affects glycosylation of the angiogenic VEGF121, a key regulator of vascular homeostasis. ERO1 deficiency, while retarding disulfide bond formation in VEGF121, increased utilization of its single N-glycosylation sequon, which lies close to an intra-polypeptide disulfide bridge, and concomitantly slowed its secretion. Unbiased mass-spectrometric analysis revealed interactions between VEGF121 and N-glycosylation pathway proteins in ERO1-knockout (KO), but not wild-type cells. Notably, MAGT1, a thioredoxin-containing component of the post-translational oligosaccharyltransferase complex, was a major hit exclusive to ERO1-deficient cells. Thus, both a reduced rate of formation of disulfide bridges, and the increased trapping potential of MAGT1 may increase N-glycosylation of VEGF121. Extending our investigation to tissues, we observed altered lectin staining of ERO1 KO breast tumor xenografts, implicating ERO1 as a physiologic regulator of protein N-glycosylation. Our study, highlighting the effect of ERO1 loss on N-glycosylation of proteins, is particularly relevant not only to angiogenesis but also to other cancer patho-mechanisms in light of recent findings suggesting a close causal link between alterations in protein glycosylation and cancer development.

3D forward stratigraphic modeling of the Albian succession in a part of the northeastern margin of the Arabian Plate and its implications for exploration of subtle traps

During the Albian age, siliciclastic input in the Arabian carbonate-dominated shelf formed important petroleum system elements. Hence, the Albian Burgan-Kazhdumi succession hosts world-class sandstone reservoirs in some Middle East oil fields. Moreover, stratigraphic traps are possible due to changes in facies and structural dips. Accordingly, we used process-based forward stratigraphy modeling as a powerful tool to predict Burgan-Kazhdumi units and de-risking new exploration prospects. A 3D stratigraphic model was constructed in this study for the first time by integrating multi-disciplines and multi-scales of seismic and well data from several countries. The model (324 km × 264 km, 4 km × 4 km grid size) encompasses NW of the Persian Gulf, Kuwait, south Iraq and SW of Iran and is vertically divided into three units based on Albian regional third-order sequences.Results indicated that the lower unit, unit-1, contains onlapping aggradational-retrogradational stacking compounds, high sand bodies thickness and distribution as well as good reservoir quality. This unit was deposited on a tide-dominated delta system. Gradually, with rising sea level, progradational fine-grain marine sedimentation dominated in units 2 and 3. Hence, intra-formational seal facies formed in the proximal and organic-rich facies in the distal intra-shelf areas. The gentle topography of the basin floor seems responsible for the lack of turbidity lobes. The sand bodies of up-dip arches such as Khafji-Norooz and Kharg-Mish highs and pinched out in fine-grained facies provide a significant potential for stratigraphic traps.The model sensitivity analysis showed eustasy, and water-driven diffusion coefficient (Kw) has the most critical impact on the clastic sedimentation of unit-1 and unit-3. Furthermore, tectonic events have the most significant sedimentation effect in unit-2 sedimentation.The findings of this study can help for better understanding of a more precise regional sequence stratigraphic and stratigraphic architecture of the Albian succession of the study area. This study also helps identify elements of petroleum plays as well as stratigraphic trap potential between mixed siliciclastic-carbonate depositional systems.

Quantum-behaved particle swarm optimization based on solitons

This paper introduces a novel variant of the quantum particle swarm optimization algorithm based on the quantum concept of particle-like solitons as the most common solutions of the quantum nonlinear Schrödinger equation. Soliton adaptation in external potentials is one of their most remarkable features which allows them to be stabilized even without a trapping potential, while the potential must be bounded for quantum particles to be localized. So we consider the motion scenario of the present algorithm based on the corresponding probability density function of quantum solitons. To evaluate the efficiency, we examine the proposed algorithm over a set of known benchmark functions, including a selection of test functions with different modalities and dimensions. Moreover, to achieve a more comprehensive conclusion about the performance, we compare it with the results obtained by particle swarm optimization (PSO), standard quantum-behaved particle swarm optimization QPSO, improved sine cosine Algorithm (ISCA), and JAYA optimization algorithm. The numerical experiments reveal that the proposed algorithm is an effective approach to solving optimization problems that provides promising results in terms of better global search capability, high accuracy, and faster convergence rate.

Probing Transport and Slow Relaxation in the Mass-Imbalanced Fermi-Hubbard Model

Constraints in the dynamics of quantum many-body systems can dramatically alter transport properties and relaxation timescales even in the absence of static disorder. Here, we report on the observation of such constrained dynamics arising from the distinct mobility of two species in the one-dimensional mass-imbalanced Fermi-Hubbard model, realized with ultracold ytterbium atoms in a state-dependent optical lattice. By displacing the trap potential and monitoring the subsequent dynamical response of the system, we identify suppressed transport and slow relaxation with a strong dependence on the mass imbalance and interspecies interaction strength, consistent with eventual thermalization for long times. Our observations demonstrate the potential for quantum simulators to provide insights into unconventional relaxation dynamics arising from constraints.