Sensitive Dependence Research Articles

Time- and temperature-dependent dynamics of prothoracicotropic hormone and ecdysone sensitivity co-regulate pupal diapause in the green-veined white butterfly Pieris napi

Diapause, a general shutdown of developmental pathways, is a vital adaptation allowing insects to adjust their life cycle to adverse environmental conditions such as winter. Diapause in the pupal stage is regulated by the major developmental hormones prothoracicotropic hormone (PTTH) and ecdysone. Termination of pupal diapause in the butterfly Pieris napi depends on low temperatures; therefore, we study the temperature-dependence of PTTH secretion and ecdysone sensitivity dynamics throughout diapause, with a focus on diapause termination. While PTTH is present throughout diapause in the cell bodies of two pairs of neurosecretory cells in the brain, it is absent in the axons, and the PTTH concentration in the haemolymph is significantly lower during diapause than during post diapause development, indicating that the PTTH signaling is reduced during diapause. The sensitivity of pupae to ecdysone injections is dependent on diapause stage. While pupae are sensitive to ecdysone during early diapause initiation, they gradually lose this sensitivity and become insensitive to non-lethal concentrations of ecdysone about 30 days into diapause. At low temperatures, reflecting natural overwintering conditions, diapause termination propensity after ecdysone injection is precocious compared to controls. In stark contrast, at high temperatures reflecting late summer and early autumn conditions, sensitivity to ecdysone does not return. Thus, here we show that PTTH secretion is reduced during diapause, and additionally, that the low ecdysone sensitivity of early diapause maintenance is lost during termination in a temperature dependent manner. The link between ecdysone sensitivity and low-temperature dependence reveals a putative mechanism of how diapause termination operates in insects that is in line with adaptive expectations for diapause.

How Manipulation Arguments Mischaracterize Determinism

I outline a heretofore neglected difference between manipulation scenarios and merely deterministic ones. Plausible scientific determinism does not imply that the relevant prior history of the universe is independent of us, while manipulation does. Owing to sensitive dependence of physical outcomes upon initial conditions, in order to trace a deterministic history, a microphysical level of analysis is required. But on this level physical laws are time-symmetrically deterministic, and causality, conceived asymmetrically, disappears. I then consider a revised scenario to resurrect the threat of manipulation even in the presence of time-symmetry and sensitive dependence upon initial conditions. To do so we posit a Designer-manipulator containing all the information of the manipulated and time-symmetrically related to him. The new scenario violates special relativity, but even waiving that objection, the scenario cannot meet its requirements. I argue that the Designer lacks agency enough to manipulate the target, both because her information lacks the robustness required to constitute knowledge of what she does, and because it leaves no room for desires for specific results.

The Influence of Pine Island Ice Shelf Calving on Basal Melting

AbstractThe combination of the Pine Island Ice Shelf (PIIS) draft and a seabed ridge beneath it form a topographic barrier, restricting access of warm Circumpolar Deep Water to a cavity inshore of the ridge, thus exerting an important control on PIIS basal ablation. In addition, PIIS has recently experienced several large calving events and further calving could significantly alter the cavity geometry. Changes in the ice front location, together with changes in ice thickness, might relax the topographic barrier and thus significantly change basal melt rates. Here, we consider the impact of past, and possible future, calving events on PIIS melt rates. We use a high‐resolution ocean model to simulate melt rates in both an idealized domain whose geometry captures the salient features of Pine Island Glacier, and a realistic geometry accurately resembling it, to explore how calving affects melt rates. The idealized simulations reveal that the melt response to calving has a sensitive dependence on the thickness of the gap between PIIS and the seabed ridge and inform our interpretation of the realistic simulations, which suggest that PIIS melt rates did not respond significantly to recent calving. However, the mean melt rate increases approximately linearly with further calving, and is amplified by approximately 10% relative to present day once the ice front reaches the ridge‐crest, taking less than one decade if calving maintains its present rate. This provides strong evidence that calving may represent an important, but as yet unexplored, contribution to the ice‐ocean sensitivity of the West Antarctic Ice Sheet.

Equivalence between two charged black holes in dynamics of orbits outside the event horizons

Using the Fermi–Dirac distribution function, Balart and Vagenas gave a charged spherically symmetric regular black hole, which is a solution of Einstein field equations coupled to a nonlinear electrodynamics. In fact, the regular black hole is a Reissner–Nordström (RN) black hole when a metric function is given a Taylor expansion to first order approximations. It does not have a curvature singularity at the origin, but the RN black hole does. Both black hole metrics have horizons and similar asymptotic behaviors, and satisfy the weak energy conditions everywhere. They are almost the same in photon effective potentials, photon circular orbits and photon spheres outside the event horizons. Due to the approximately same photon spheres, the two black holes have no explicit differences in the black hole shadows and constraints of the black hole charges based on the First Image of Sagittarius A $$^{*}$$ . There are relatively minor differences between effective potentials, stable circular orbits and innermost stable circular orbits of charged particles outside the event horizons of the two black holes immersed in external magnetic fields. Although the two magnetized black holes allow different construction methods of explicit symplectic integrators, they exhibit approximately consistent results in the regular and chaotic dynamics of charged particles outside the event horizons. Chaos gets strong as the magnetic field parameter or the magnitude of negative Coulomb parameter increases, but becomes weak when the black hole charge or the positive Coulomb parameter increases. A variation of dynamical properties is not sensitive dependence on an appropriate increase of the black hole charge. The basic equivalence between the two black hole gravitational systems in the dynamics of orbits outside the event horizons is due to the two metric functions having an extremely small difference. This implies that the RN black hole is reasonably replaced by the regular black hole without curvature singularity in many situations.

Recent advances in clustered regularly interspaced short palindromic repeats-based detection of severe acute respiratory syndrome coronavirus 2

严重急性呼吸综合征冠状病毒2(SARS-CoV-2)导致的新冠肺炎(COVID-19)迅速蔓延全球,给全球公共卫生系统带来了挑战。由于逆转录-定量聚合酶链反应(RT-qPCR)和抗原测试的普遍适用性和灵敏度较差,并且具有不同突变的SARS-CoV-2变体持续的出现,给疫情防控带来了更大的挑战,因此,高灵敏度、无需设备并且能够区分SARS-CoV-2变体的诊断方法亟须发展。基于成簇的规则间隔短回文重复序列(CRISPR)的诊断对设备要求低,具有可编程性、灵敏性和易用性,已经发展出多种核酸检测工具用于传染病的诊断,其在临床上具有巨大的应用潜力。文章聚焦于近期发表的基于CRISPR实现SARS-CoV-2检测和变体区分的最新技术,总结其特点并对其发展进行了展望。

An Axial Airgap Eddy Current Speed Sensor

This article presents a novel configuration of the eddy current speed sensor to measure the rotating speed of iron rods and shafts up to 3000 r/min. The proposed eddy current speed sensor has an axial airgap structure with one excitation coil and two antiserially connected pick up coils. The speed sensor is mounted in the end shaft part region. Different solid iron materials for rotating shaft are considered in the measurements and calculations to evaluate solid iron material effect on the eddy current speed sensor performance. Two-dimensional (2-D) and 3-D finite element method is utilized for the performance analysis of the speed sensor. Also, a 2-D analytical method is developed for parametric analysis. A copper rod is also used to compare the speed sensor with the rotating iron shaft and copper shaft. Finally, two thin copper discs with different diameters are mounted on the solid iron shaft and their influences on the eddy current speed sensor were evaluated and measured to increase sensitivity and decrease sensor dependency on the permeability of the solid iron shaft. The achieved nonlinearity errors are about ±0.2%.

Optimization of the technology for designing sensitive gas sensors based on zinc oxide using a sol-gel method

This paper has investigated the nanostructured samples of zinc oxide intended for use as a gas sensor. Experimental samples were obtained by the economical sol-gel method, suitable for large-scale production. The dependence of the efficiency of gas sensors based on zinc oxide on temperature was established. The electrical properties of experimental samples were investigated in the air in the range of values of the initial voltage of 5–30 V and at temperatures of 320, 370, and 450 K. It was established that the current-voltage characteristic for nanosized zinc oxide is non-ohmic, but the nature of the curves can change due to an increase in the operating temperature. The obtained experimental dependences are explained by the peculiarities of the morphology of the obtained nanostructured zinc oxide, which affects the value of the contact resistance in the structure. A large number of nanoscale particles leads to an increase in the number of energy barriers, which negatively affects the sensitivity of experimental samples to the gaseous medium. The study of the sensitivity of samples to the established gaseous medium, namely 100 ppm CO, was carried out. The electrical conductivity of zinc oxide is determined by oxygen vacancies that are electron donors, and, accordingly, the conductivity activation energy is determined by the donor levels formed by vacancies in the ZnO forbidden zone. During heating, there is a decrease in the resistance of the sample with increasing temperature; electrical conductivity is determined by the thermal generation of electrons. Understanding the dependence of the sensor sensitivity on temperature and the use of sensitive ZnO layers of different morphology will make it possible to recognize gaseous components in a complex mixture.

Penetration of linear chains into semiflexible knotted rings in linear-ring blends

Threading of ring chains by linear chains has a great effect on the long-time dynamics of the ring chains in linear-ring blends. In this paper, we performed coarse-grained molecular dynamics simulations on the mixtures of linear and ring chains to investigate the effects of chain rigidity on the penetration of knotted rings threaded by linear chains. As the chain rigidity Kb of rings increases, non-trivial rings exhibit a non-monotonous dependence of the chain-penetration on chain rigidity Kb, and the semiflexible knotted rings with Kb = 10 have the maximum chain-penetration ability. This anomalous result is due to the two competing effects: As the chain rigidity of rings increases, one is that the swollen of rings can create more free space in favour of chain penetration, and another is that the formation of ordered clusters for rings in which rings tend to get parallel to each other can strongly hinder linear chains to penetrate into rings. Meanwhile, the transition from disordered to ordered phase for the trivial rings in linear-ring blends is a quite sensitive dependence on the chain rigidity of rings, resulting in a sudden transition at Kb = 12.

Indentation creep deformation behavior of local zones for X70 girth weld

Creep failure of in-service pipes is a fundamental engineering issue. Since the girth weld joint is a weak link in the pipeline, the creep deformation behavior of the girth weld must be carefully researched. This research sheds light on determining the local creep properties of girth welds. The creep deformation behavior of local zones for the X70 girth weld was studied using nanoindentation creep experiments with maximum nano-indenter loads of 10 mN, 50 mN, and 100 mN. The load dependency and creep mechanism of local zones for the X70 girth weld were investigated through creep properties such as creep strain rate, creep stress, creep stress index, and strain rate sensitivity index. In addition, the microstructures of base material (BM), root welding zone (RWZ), and heat-affected zone (HAZ) were studied to determine the differences in creep properties for the girth weld's local zones. The creep displacement of BM, RWZ, and HAZ follow the RWZ > BM > HAZ sequence as the maximum load increases. The creep stress, on the other hand, exhibits HAZ > RWZ > BM sequence. Furthermore, RWZ and HAZ have a higher load dependency of creep stress index and strain rate sensitivity than BM.

Unravelling the Size‐Dependent Mechanical Properties of Nanocrystalline Face‐Centered‐Cubic Metals: From the Dislocation Point of View

The grain size dependence of strain rate sensitivity, apparent activation volume, and yield stress of nanocrystalline (NC) face‐centered‐cubic metals (FCC) are modeled based on the bow‐out model of single dislocation. It is found that the grain size limitation on the dislocation length gives rise to the grain size effects on the mechanical properties. The model gives predictions that when temperature is at or below room temperature and the strain rate is in the quasistatic range, dislocation‐mediated mechanisms play a dominant role in the plastic deformations of FCC NC metals even for the grain size of several nanometers, which is consistent with known experimental and simulation results. Based on the model, abnormal mechanical phenomena of nanostructured metals, such as the appearance of the inverse Hall–Petch relationship, the existence of the critical grain size, and its strain rate dependence, are well predicted and interpreted.

Bistability in Coupled Opto-Thermal Micro-Oscillators

In this work, we experimentally investigate the dynamics of pairs of opto-thermally driven, mechanically coupled, doubly clamped, silicon micromechanical oscillators, and numerically investigate the dynamics of the corresponding lumped-parameter model. Coupled limit cycle oscillators exhibit striking nonlinear dynamics and bifurcations in response to variations in system parameters. We show that the input laser power influences the frequency detuning between two non-identical oscillators. As the laser power is varied, different regimes of oscillations such as the synchronized state, the drift state, and the quasi-periodic state are mapped at minimal and high coupling strengths. For non-identical oscillators, coexistence of two states, the synchronized state and the quasi-periodic state, is demonstrated at high coupling and high laser power. Experimentally, this bistability manifests as irregular oscillations as the system rapidly switches between the two states due to the system’s sensitive dependence on initial conditions in the presence of noise. We provide a qualitative comparison of the experimental and numerical results to elucidate the behavior of the system. [2022-0005]

Approximate inversion for Abel integral operators of variable exponent and applications to fractional Cauchy problems

We investigate the variable-exponent Abel integral equations and corresponding fractional Cauchy problems. The main contributions of the work are enumerated as follows: (i) We develop an approximate inversion technique for variable-exponent Abel integral operators, based on which we analyze the corresponding integral and differential equations; (ii) We prove that the sensitive dependence of the well-posedness of classical Riemann-Liouville fractional differential equations on the initial value could be resolved by adjusting the initial value of the variable exponent; (iii) We prove that the singularity of the solutions to the Riemann-Liouville fractional differential equations could also be eliminated by adjusting the variable exponent and its derivatives at the initial time, which, together with (ii), demonstrates the advantages of introducing the variable exponent. The proposed approximate inversion technique provides a potential means to convert the intricate variable-exponent integral and differential problems to feasible forms, and the above findings suggest that the variable-exponent fractional problems may serve as a connection between integer-order and fractional models by adjusting the variable exponent at the initial time.

Preparation and properties of co-mixed crystals of 1,3-di- and 1,3,5-tri-amino-2,4,6-trinitrobenzenes with attractive cyclic nitramines

Co-agglomeration was used to prepare co-mixed crystals of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) with RDX, β-HMX, BCHMX and ε-CL-20. The molecular rearrangements in mixed crystals were verified using Raman, FTIR, and PXRD techniques. The significant stretching vibrations indicated that the resultant co-agglomerates (CACs) are co-crystals (CCs), where HMX appears in its δ-modification and CL-20 in its β-modification. Logical relationships, described already for the 1,3-diamino-2,4,6-trinitrobenzene (DATB) CACs, between some FTIR and Raman vibrational modes and parameters of their initiation and detonation, after extending with the data for the TATB analogues, produced greater predictability. The densities of TATB CACs are higher than those of the pure nitramines (including β-CL-20). An evaluation of the dependence of the impact sensitivity on the performance or energy content in the DATB and TATB CACs is consistent with the Licht’s rule with some exceptions for DATB and an unambiguous relationship for the use of the heat of combustion as a representative of performance for TATB. This sensitivity is quite strongly reduced in the TATB CACs compared to their DATB analogues. The detonation energies of the DATB and TATB CACs are higher than would be expected from the percentage of co-formers in them. Among the CACs studied, the most interesting appears to be HMX/TATB, which has a density slightly greater than pure HMX, with only slightly reduced detonation parameters, while its impact resistance is extremely high.

Temperature-dependent sensitivity of iodide chemical ionization mass spectrometers

Abstract. Iodide chemical ionization mass spectrometry (CIMS) is a common analytical tool used in both laboratory and field experiments to measure a large suite of atmospherically relevant compounds. Here, we describe a systematic ion molecule reactor (IMR) temperature dependence of iodide CIMS analyte sensitivity for a wide range of analytes in laboratory experiments. Weakly bound iodide clusters, such as HCl, HONO, HCOOH, HCN, phenol, 2-nitrophenol, and acyl peroxynitrate (PAN) detected via the peroxy radical cluster, all exhibit strong IMR temperature dependence of sensitivity ranging from −3.4 % ∘C−1 to 5.9 % ∘C−1 (from 37 to 47 ∘C). Strongly bound iodide clusters, such as Br2, N2O5, ClNO2, and PAN detected via the carboxylate anion, all exhibit little to no IMR temperature dependence ranging from 0.2 % ∘C−1 to −0.9 % ∘C−1 (from 37 to 47 ∘C). The IMR temperature relationships of weakly bound clusters provide an estimate of net reaction enthalpy, and comparison with database values indicates that these clusters are in thermal equilibrium. Ground site HCOOH data collected in the summer of 2021 in Pasadena (CA) are corrected and show a reversal in the diel cycle, emphasizing the importance of this correction (35±6 % during the day, -26±2 % at night). Finally, we recommend two approaches to minimize this effect in the field, namely heating or cooling the IMR; the latter technique has the added benefit of improving absolute sensitivity.

Nanopore sequencing technology and its application in plant virus diagnostics.

Plant viruses threaten crop yield and quality; thus, efficient and accurate pathogen diagnostics are critical for crop disease management and control. Recent advances in sequencing technology have revolutionized plant virus research. Metagenomics sequencing technology, represented by next-generation sequencing (NGS), has greatly enhanced the development of virus diagnostics research because of its high sensitivity, high throughput and non-sequence dependence. However, NGS-based virus identification protocols are limited by their high cost, labor intensiveness, and bulky equipment. In recent years, Oxford Nanopore Technologies and advances in third-generation sequencing technology have enabled direct, real-time sequencing of long DNA or RNA reads. Oxford Nanopore Technologies exhibit versatility in plant virus detection through their portable sequencers and flexible data analyses, thus are wildly used in plant virus surveillance, identification of new viruses, viral genome assembly, and evolution research. In this review, we discuss the applications of nanopore sequencing in plant virus diagnostics, as well as their limitations.

First-principles calculation of gate-tunable ferromagnetism in magic-angle twisted bilayer graphene under pressure

Magic-angle twisted bilayer graphene (MATBG) is notable as a highly tunable platform for investigating strongly correlated phenomena such as unconventional superconductivity and quantum spin liquids, due to easy control of doping level through gating and sensitive dependence of the magic angle on hydrostatic pressure. Experimental observations of correlated insulating states, unconventional superconductivity and ferromagnetism in MATBG indicate that this system exhibits rich exotic phases. In this work, using density functional theory calculations in conjunction with the effective screening medium method, we find the MATBG under pressure at a twisting angle of 2.88∘ and simulate how its electronic states evolve when doping level and electric field perpendicular to plane are tuned by gating. Our calculations show that, at doping levels between two electrons and four holes per moiré unit cell, a ferromagnetic (FM) solution with spin density localized at AA stacking sites is lower in energy than the nonmagnetic solution. The magnetic moment of this FM state decreases with both electron and hole doping and vanishes at four electrons/holes doped per moiré unit cell. Hybridization between the flat bands at the Fermi level and the surrounding dispersive bands can take place at finite doping. On increasing the out-of-plane electric field at zero doping, a transition from the FM state to the nonmagnetic one is seen. An investigation of impurity effects shows that both absorption of molecules and occurrence of Stone–Wales impurities suppress the FM state, and the mechanisms are understood from our calculations. We also analyze the interlayer bonding character due to flat bands via Wannier functions. Finally, we report trivial band topology of the flat bands in the FM state at a certain doping level.

Cavity length dependence on strain sensitivity for Fabry–Perot sensors

This study presents the dependence of strain sensitivity on cavity length in conventional Fabry–Perot (F-P) sensors. A high number of F-P sensors were required and to ensure their reproducibility, a manufacturing process was developed to obtain similar sensors but with different types of lengths. A hollow-core silica tube was used to fabricate several F-P cavities by fusion splicing it between two sections of SMF28 fiber. The fabricated F-P has a varying length ranging from 15 to 2500 μm. The cavities were measured under a microscope and the reflected spectrum was acquired for each one. Strain measurements were performed for a maximum strain of 1000 με. The strain sensitivity showed a highly linear correlation with ∆λFSR. Small length variations for short cavities heavily affect the FSR value. The smallest and longest cavities present sensitivities of 8.71 and 2.68 pm/με, respectively. Thermal characterization for low- and high-temperature regimes was also performed and is constant for tested sensors.

Three Kinds of Butterfly Effects within Lorenz Models

Within Lorenz models, the three major kinds of butterfly effects (BEs) are the sensitive dependence on initial conditions (SDIC), the ability of a tiny perturbation to create an organized circulation at large distances, and the hypothetical role of small-scale processes in contributing to finite predictability, referred to as the first, second, and third kinds of butterfly effects (BE1, BE2, and BE3), respectively. A well-accepted definition of the butterfly effect is the BE1 with SDIC, which was rediscovered by Lorenz in 1963. In fact, the use of the term “butterfly” appeared in a conference presentation by Lorenz in 1972, when Lorenz introduced the BE2 as the metaphorical butterfly effect. In 2014, the so-called “real butterfly effect”, which is based on the features of Lorenz’s study in 1969, was introduced as the BE3.

Increasing model vertical resolution may not necessarily lead to improved atmospheric predictability.

The widely accepted existence of an inherent limit of atmospheric predictability is usually attributed to weather's sensitive dependence on initial conditions. This signature feature of chaos was first discovered in the Lorenz system, initially derived as a simplified model of thermal convection. In a recent study of a high-dimensional generalization of the Lorenz system, it was reported that the predictability of its chaotic solutions exhibits a non-monotonic dimensional dependence. Since raising the dimension of the Lorenz system is analogous to refining the model vertical resolution when viewed as a thermal convection model, it is questioned whether this non-monotonicity is also found in numerical weather prediction models. Predictability in the sense of sensitive dependence on initial conditions can be measured based on deviation time, that is, the time of threshold-exceeding deviations between the solutions with minute differences in initial conditions. Through ensemble experiments involving both the high-dimensional generalizations of the Lorenz system and real-case simulations by a numerical weather prediction model, this study demonstrates that predictability can depend non-monotonically on model vertical resolution. Further analysis shows that the spatial distribution of deviation time strongly contributes to this non-monotonicity. It is suggested that chaos, or sensitive dependence on initial conditions, leads to non-monotonic dependence on model vertical resolution of deviation time and, by extension, atmospheric predictability.

Al2O3:C and LiF: Mg, Ti characterisations at 100–150 kV energy range for computed tomography dose measurement

Performance characterisation has been carried out of nanoDot™ OSLDs and TLD-100™, validating their use for diagnostic x-ray dose profile assessments. Investigations include optical annealing, signal depletion, signal fading, dose-response, sensitivity, and energy dependence. Both dosimeter types were exposed using the Constant Potential Industrial X-ray (Model Philips MG 165) in Standard Radiation Qualities (RQT) procedure located in Nuclear Malaysia, Bangi. OSLD annealing using a 14 W compact fluorescent lamp showed an average signal loss of ∼93% as a result of 60 min of illumination. For dosimetric signal depletion, screened nanoDot™ OSLDs gave rise to the most favorable performance, with a mean signal loss of 1.0% per reading. In respect of signal fading, similar favorable performance was found for the screened nanoDot™ OSLDs, after a stabilisation period of 11–12 days post-irradiation, the average reading decreased by ∼1% over a further 17 days. For doses up to 500 mGy the TLD-100™ and screened nanoDot™ OSLDs both provide a highly linear response, with a regression coefficient of 0.999 in both cases. Linear energy dependence was found for RQT spectra from 100 to 150 kV.