Sign Change Research Articles

Thermodynamic information geometry of criticality, fluctuation anomaly and hyperscaling breakdown in the spin-3/2 chain

Equilibrium state space geometry is worked out for the exactly solved one-dimensional spin-3/2 lattice with a Blume–Emery–Griffiths (BEG) Hamiltonian as well as a more general one with a non-zero field coupled to the octopole moments. The phase behaviour of the spin-3/2 chain is revisited and novel observations of anomaly in the hyperscaling relation and in the decay of fluctuations are reported for the first time. Using the method of constrained fluctuations developed earlier in Sahay (2017); Sanwari and Sahay (2022) three appropriate state space sectional curvatures and a 3d curvature are shown to separately encode dipolar, quadrupolar and octopolar correlations both near and away from pseudo-criticality. In all observations of hyperscaling breakdown the 3d scalar curvature is found to encode the correlation length while the relevant sectional curvature equals the inverse of singular free energy. For parameter values where the order parameter fluctuation anomalously decays despite a divergence in its correlation length the relevant scalar curvature undergoes a sign change to positive values, signalling a possible change in the nature of the underlying statistical interactions.

Framework to elicit consent from lightly sedated mechanically ventilated intensive care patients in nursing practice.

The study aimed to ascertain a framework of nursing practices to elicit consent from lightly sedated ventilated patients. Study participants were nurses working in intensive care and critical care wards, whose observations and semi-structured interviews were assessed using a modified grounded theory approach. A total of 15 concepts were generated, from which three categories and three subcategories were generated. Category 1: Nurses taking the lead in providing assistance by sharing signs of change while continuing the invasive treatment, working to maintain the patient's life, alleviation of pain, promotion of awareness of the current situation, and acclimating them to the treatment environment as the basis for building a relationship between patients and nurses. Category 2: Searching for points of agreement and reaching a compromise involves the nurse drawing out the patient's thoughts, hopes, and expectations, and transforming the relationship into a patient-centered one by sharing goals with the patient in order to achieve them. Category 3: Organizing collaboration within care supported the patient's ability to move safely while maintaining the patient's pace to achieve shared goals, and guided the patient's independent actions. Even when patients recover from an acute life-threatening situation, their physical sensations remain vague and their functional decline continues. Rather than simply eliciting consent from patients, the structure of nursing practice to elicit such response from patients involves drawing out the patient's thoughts, hopes, and expectations, as well as guiding the patient toward goals that they have created together with the nurse and utilizing the patient's strengths to achieve these goals.

Diffusiophoretic Transport of Charged Colloids in Ionic Surfactant Gradients Entirely below versus Entirely above the Critical Micelle Concentration.

When placed in an ionic surfactant gradient, charged colloids will undergo diffusiophoresis at a velocity, uDP = MDP∇ ln S, where MDP is the diffusiophoretic mobility and S is the surfactant concentration. The diffusiophoretic mobility depends in part on the charges and diffusivities of the surfactants and their counterions. Since micellization decreases surfactant diffusivity and alters charge distributions in a surfactant solution, MDP of charged colloids in ionic surfactant gradients may differ significantly when surfactant concentrations are above or below the critical micelle concentration (CMC). The role of micelles in driving diffusiophoresis is unclear, and a previously published model that accounts for micellization suggests the possibility of a change in the sign of MDP above the CMC [Warren, P. B.; . Soft Matter 2019, 15, 278-288]. In the current study, microfluidic channels were used to measure the transport of negatively charged polystyrene colloids in sodium dodecyl sulfate (SDS) surfactant gradients established at SDS concentrations that are either fully above or fully below the CMC. Interpretation of diffusiophoresis was aided by measurements of the colloid electrophoretic mobility as a function of SDS concentration. A numerical transport model incorporating the prior diffusiophoretic mobility model for ionic surfactant gradients was implemented to elucidate signatures of positive and negative diffusiophoretic mobilities and compare with experiments. The theoretically predicted sign of the diffusiophoretic mobility below the CMC was determined to be particularly sensitive to uncertainty in colloid and surfactant properties, while above the CMC, the mobility was consistently predicted to be positive in the SDS concentration range considered in the experiments conducted here. In contrast, experiments only showed signatures of a negative diffusiophoretic mobility for these negatively charged colloids with no change of sign. Colloid diffusiophoretic transport measured in micellar solutions was more extensive than that below the CMC with the same ∇ ln S.

Entangling Interactions Between Artificial Atoms Mediated by a Multimode Left-Handed Superconducting Ring Resonator

Superconducting metamaterial transmission lines implemented with lumped circuit elements can exhibit left-handed dispersion, where the group and phase velocity have opposite sign, in a frequency range relevant for superconducting artificial atoms. Forming such a metamaterial transmission line into a ring and coupling it to qubits at different points around the ring results in a multimode bus resonator with a compact footprint. Using flux-tunable qubits, we characterize and theoretically model the variation in the coupling strength between the two qubits and each of the ring-resonator modes. Although the qubits have negligible direct coupling between them, their interactions with the multimode ring resonator result in both a transverse exchange coupling and a higher-order ZZ interaction between the qubits. As we vary the detuning between the qubits and their frequency relative to the ring-resonator modes, we observe significant variations in both of these interqubit interactions, including zero crossings and changes of sign. The ability to modulate interaction terms such as the ZZ scale between zero and large values for small changes in qubit frequency provides a promising pathway for implementing entangling gates in a system capable of hosting many qubits. Published by the American Physical Society 2024

A modified orthotopic left lung transplantation model in rats

To enhance the operability of the rat orthotopic left lung transplantation model, we implemented several improvements and meticulously detailed the procedure. One hundred and thirty-one healthy male Sprague Dawley rats, weighing between 250 and 300 g, were utilized, with 64 serving as donors, 64 as recipients, and 3 as sham controls. We employed a modified three-cuff technique for the orthotopic left lung transplantation. Notably, our modified perfusion method could prevent donor lung edema, while waist-shaped cuffs minimized suture slippage during anastomosis. Additionally, positioning the recipient rat in a slightly left-elevated supine position during anastomosis reduced tension on the lung hilum, thus mitigating the risk of vascular laceration. The introduction of a unique two-person anastomosis technique significantly reduced operation time and substantially improved success rates. Furthermore, maximizing inflation of donor lungs both during preservation and surgery minimized the occurrence of postoperative atelectasis. Various other procedural refinements contributed to the enhanced operability of our model. Sixty-four rat orthotopic left lung transplantations were performed with only one surgical failure observed. The acquisition time for donor lungs averaged (19 ± 4) minutes, while (11 ± 1) minutes were allocated for donor lung hilum anatomy and cuff installation. Recipient thoracotomy and left lung hilar anatomy before anastomosis required (24 ± 8) minutes, with anastomosis itself taking (31 ± 6) minutes. Remarkably, the survival rate at the 4-h postoperative mark stood at 96.7 %. Even six months post-operation, transplanted left rat lungs continued to exhibit proper inflation and contraction rhythms, displaying signs of chronic pathological changes. In summary, our modified rat model of orthotopic left lung transplantation demonstrates robust operability, significantly reducing surgical duration, improving operation success rates, and enhancing postoperative survival rates. Furthermore, its long-term survival capacity enables the simulation of acute and chronic disease processes following lung transplantation.

Exploring the challenges of interpreting near-surface towed transient electromagnetic data on saline permafrost

We analyze a continuous near-surface transient electromagnetic (TEM) survey on permafrost around Ilulissat in western Greenland, an area characterized by continuous saline permafrost. The TEM data are severely affected by induced polarization (IP) effects, causing a large range of decay shapes. We identify seven unique decay shapes: oversteepened, sign change, all negative, double sign change, no apparent IP, flat spot, and positive nonmonotonic, the last two of which have not previously been identified in the scientific literature. A clear spatial dependency of the decay shapes is observed. Inversion of the data is carried out using a Cole-Cole model that poses a highly nonunique inversion problem with an extreme starting-model dependency. A series of inversion and forward-modeling experiments demonstrate these challenges and indicate that a low-resistivity and highly chargeable layer with time constant ([Formula: see text]) values between [Formula: see text] and [Formula: see text] and frequency exponent ( C) values above 0.74 is needed to fit the data used in the inversion experiment. Forward modeling further indicates that low [Formula: see text] and high C values are needed to reproduce the observed flat-spot and positive-nonmonotonic decay shapes. Based on these observations, we attribute the IP effects to the orientational polarization of ice in the soil column. This mechanism allows for low-resistivity, high-chargeability layers due to partially frozen saline sediments, a combination that is difficult to explain by the IP mechanisms traditionally considered. Based on the forward modeling of a realistic structural model of a layered sediment pack over dipping bedrock, we are able to reproduce all the observed decay shapes. This model provides a consistent framework for qualitative interpretation of the entire data set and evidence for the presence of saline deposits in the central parts of the sedimentary basins.

Giant intraperitoneal non-pancreatic pseudocyst: a case report

IntroductionNon-pancreatic pseudocysts are rare lesions that typically form from the omentum and mesentery. These cysts have a thick fibrotic wall made up of fibrous tissue and may show signs of calcifications and inflammatory changes. The fluid inside them can vary, ranging from hemorrhage and pus to serous or sometimes chylous content. In most cases, these cysts appear as a result of trauma, surgery, or infection.Case presentationA 35-year-old male patient from Ethiopia presented with swelling in his lower abdomen that had been present for 2 years. Initially, the swelling was small but gradually increased in size. The patient experienced frequent urination but no pain or difficulty during urination, urgency, intermittent urination, or blood in the urine. The swelling was initially painless but became painful 2 months prior to his presentation. Abdominal computed tomography scans revealed a well-defined, lobulated peritoneal lesion measuring 16 × 12 × 10 cm, consisting primarily of fluid-filled cysts with a thick, enhancing wall and septa. Additionally, there was a large, heterogeneous enhancing soft tissue component measuring 8 × 6 cm. As a result, the cystic mass was surgically removed in its entirety with partial removal of the bladder wall, and the patient was discharged in an improved condition.ConclusionPrimary non-pancreatic pseudocysts are extremely rare lesions that must be differentiated from other possible causes of cystic lesions within the peritoneal or retroperitoneal regions. Surgeons should be aware of the potential occurrence of these lesions, which may have an unknown origin.

Experimental and numerical investigations on the acoustoelastic effect in hyperelastic waveguides

Guided ultrasonic wave based structural health monitoring has been of interest over decades. However, the influence of prestress states on the propagation of Lamb waves in thin-walled structures is not fully covered yet. So far experimental work presented in the literature only focuses on a few individual frequencies, which does not allow a comprehensive verification of the numerous numerical investigations. Furthermore, most work is based on the strain-energy density function by Murnaghan. To validate the common modeling approach and to investigate the suitability of other nonlinear strain-energy density functions, an extensive experimental and numerical investigation covering a large frequency range is presented here. The numerical simulation comprises the use of the Neo-Hooke as well as the Murnaghan material model. It is found that these two material models show qualitatively similar results. Furthermore, the comparison with the experimental results reveals that the Neo-Hooke material model reproduces the effect of prestress on the difference in the Lamb wave phase velocity very well in most cases. For the [Formula: see text] wave mode at higher frequencies, however, the sign of this difference is only correctly predicted by the Murnaghan model. In contrast to this, the Murnaghan material model fails to predict the sign change for the [Formula: see text] wave mode.

The Impact of Climate Change on Food Security and Natural Resource Management in Smallholder Crop Farming Systems at Mthonjaneni Local Municipality, Kwazulu-Natal, South Africa

This study assessed the impact of climate change on food security and natural resource management on crop farming systems. Forty-five respondents were interviewed using an open-ended, and structured questionnaire. The open-ended questions allowed respondents to share their thoughts and experiences in their own words, while the structured questions helped to ensure that all respondents were asked the same questions and that the data collected was consistent. The results of this study showed that smallholder farmers perceived an increase in hot days (51.1%), a decrease in rainfall (51.1%), and a decrease in flood occurrence (71.1%). In addition, 95.2% of the respondents indicated that climatic conditions have influenced their farming systems. Natural resource changes noticed by farmers because of climate change include reduced grazing feedlot for livestock farmers (85%), reduced herbaceous cover (80%), decline in volume of water (57.8%), and increased tree damage and land degradation (11.1%). Increased soil erosion (6.7%) and increased bush encroachment (2.2%) were some of the natural resource challenges facing smallholder farmers. Some signs of climate change experienced by farmers included increases in crop pests (71%) and crop disease (8,9%). The adaptation strategies applied included the following: use of water harvesting, use of little soil disturbance techniques, adjusted fertiliser use, application of different planting dates techniques, use of different crop varieties, use of drought tolerant seeds, applied crop diversification, use of techniques that shortened growth length, planting new trees and avoiding planting on sloppy areas, and applied soil conservation techniques. Agriculture extension advisors should address vulnerable systems, including agricultural water and natural resources. In addition, it is important for agriculture extension advisors to strengthen the link between climate change adaptation and key climate change policy processesto improve their effectiveness and ability to deal with the effects of climate change. This will help overcome shortcomings along the food value chain and ensure food security.

A challenging case of severe bilateral septic arthritis with osteomyelitis of the sternoclavicular joint in a patient with end-stage renal disease.

Septic arthritis of the sternoclavicular joint (SCJ) is a rare condition that comprises <1% of all joint infections. We report a case of severe bilateral septic arthritis of the SCJ in a patient with end-stage renal disease on peritoneal dialysis. A 44-year-old female presented with right SCJ infection 1 month after recovering from a tenckhoff catheter exit-site infection. She completed 6 weeks of antibiotics however this progressed to bilateral SCJ septic arthritis with osteomyelitis necessitating multiple surgical debridement and excision of bilateral clavicular heads. Further imaging showed signs of renal osteodystrophy and degenerative joint changes resembling calcium pyrophosphate deposition. Patients with end-stage renal disease have multiple risk factors including immune system dysfunction, renal osteodystrophy and dialysis access sites that increase susceptibility to bacteraemia and seeding. Therefore in such patients, prompt assessment is necessary to ensure expeditious diagnosis and treatment of this potentially debilitating condition. A multidisciplinary team involving various specialties is crucial for the holistic care for such patients and to reduce the risk of recurrence.

Determining the Optimal Dosage of Dexmedetomidine for Smooth Emergence in Older Patients Undergoing Spinal Surgery: A Study of 44 Cases.

BACKGROUND Emergence agitation, or delirium, occurs during early recovery from general anesthesia and involves disorientation, excitation, and uncontrolled physical movements. Dexmedetomidine is an alpha agonist that has sedative, anxiolytic, analgesic, and sympatholytic activities and is used as a continuous infusion to prevent emergence agitation. This study aimed to evaluate patients aged 65 years and older undergoing general anesthesia to determine the 90% effective dose (ED90) of dexmedetomidine continuous intraoperative infusion to prevent emergence agitation. MATERIAL AND METHODS We enrolled 44 patients aged 65 years and older undergoing spinal surgery under general anesthesia. Dexmedetomidine administration commenced 30 minutes before surgery completion, with a predetermined infusion dose (μg/kg/h), without a loading dose. The initial dose was 0.2 μg/kg/h, and subsequent step size was ±0.05 μg/kg/h. We tried to find ED90 of dexmedetomidine using the biased-coin design. Vital signs, extubation quality scores, extubation-related complications, and postoperative outcomes were monitored. RESULTS Dexmedetomidine ED₉₀ for smooth emergence in older patients was 0.34 μg/kg/h. Peri-extubation vital signs remained within 20% of baseline values, without requiring pharmacological intervention. No hypoxia, hypoventilation, or post-extubation agitation occurred. In the recovery room, 1 patient briefly exhibited excitement but quickly calmed. Nine patients initially unresponsive in the recovery room fully awoke and were promptly discharged. CONCLUSIONS For older patients who are vulnerable to adverse effects of anesthetics and opioids, dexmedetomidine enables gentle awakening without adverse vital sign changes, respiratory depression, excessive sedation, or emergence agitation (ED₉₀=0.34 μg/kg/h). Further studies should involve a larger patient cohort, considering diverse medical conditions in older individuals.

An Analysis of Meteorological Data in Sumatra and Nearby using Agglomerative Clustering

Sumatra is one of the biggest and the second most crowded islands in Indonesia. Sumatra is also a place of abundance of tropical flora and fauna. This paper aims to cluster the cities in Sumatra and nearby based on the meteorology data. It implements Agglomerative hierarchical clustering and uses a daily time series dataset from 17 cities from 1 January 2010 to 31 December 2023. The dataset contains variables minimum temperature, maximum temperature, average temperature, humidity, sunshine duration, and average wind speed. The preprocessing data was dedicated to managing the missing values and data aggregation to create single-form data. The single-form data contains cities and meteorological variables used as an input for the clustering algorithm, i.e. K-Means, Fuzzy C-Means, K-Medoid, intelligent K-KMeans, and Agglomerative clustering. The Agglomerative clustering outperforms other methods (i.e. K-Means, Fuzzy C-Means, K-Medoid, and intelligent K-KMeans) and produces Silhouette scores of 0.11. The clusters are then analyzed to find their unique pattern. The cut-off when the number cluster is two, Agglomerative hierarchical clustering gathers Aceh, Sabang, Pekanbaru, Padang, and Padang Lawas in Cluster 1. Other cities, i.e., Nagan Raya, Batam, Jambi, Bandar Lampung, Medan, Pangkalpinang, Palembang, Bengkulu, Belitung, Tapanuli, Deli Serdang, and Nias are in Cluster 2. The results can be briefly explained that the characteristic of Cluster 1 has a higher average temperature, lower humidity, and lower sunshine duration than cities in Cluster 2. However, Cluster 1 has a lower average minimum temperature than Cluster 2. The pairs of cities which have the most similarities are (Aceh, Sabang), (Pekanbaru, Padang Lawas), (Nagan Raya, Nias), (Jambi, Palembang), (Bengkulu, Tapanuli), and (Medan, Deli Serdang). The annual trend in several cities shows that there exists an increasing trend in minimum temperature, rising sunshine duration, and decreasing wind speed. These are signs of climate change that need a proper handling.

Modeling of polarization reversal-induced interface sheet charge in wurtzite-type AlScN/GaN heterostructures

In this work, the value and the polarity of the spontaneous and piezoelectric polarization have been investigated, as the use of two different reference structures for wurtzite-type group-III nitrides, namely, the zinc-blende and the layered-hexagonal crystal lattice, have resulted in different predictions. It was found that although the differences in value and polarity of the polarization for heterostructures such as wurtzite Al1−xScxN/GaN lead to similar interface sheet charges, a significant mismatch is observed when polarization reversal is considered. The interface sheet charge predicted before and after the polarization reversal in the wurtzite Al1−xScxN layer on GaN using the zinc-blende lattice as a reference predominantly shows a change in sign. When using the layered-hexagonal lattice as a reference, not only is the same polarity of the interface sheet charge maintained after polarization reversal, but it is even 30 times larger. In this case, the giant and positive spontaneous polarization values for metal-polar Al1−xScxN extracted from the ferroelectric switching, as well as the alignment of the piezoelectric polarization to it, were observed to be consistent with the predictions referenced to the layered-hexagonal lattice. Thus, it is concluded that the layered-hexagonal reference is not only more suitable for predicting the ferroelectric properties of wurtzite Al1−xScxN but should also be the correct reference when considering polarization reversal in heterostructures. If the significant increase in the interface sheet charge after polarization reversal is experimentally detected, it will allow the design and fabrication of novel devices for future high-frequency and power electronics applications.

Shape Sensing of Cantilever Column Using Hybrid Frenet-Serret Homogeneous Transformation Matrix Method.

The Frenet-Serret (FS) framework stands as a pivotal tool in shape sensing for various infrastructures. However, this tool suffers from accumulative errors, particularly at inflection points where the normal vector undergoes sign changes. To minimize the error, the traditional FS framework is modified by incorporating the homogeneous matrix transformation (HMT) method for segments containing inflection points. Additionally, inclination information is also used to calculate the unit tangent vector and the unit norm vector at the start point of each segment. This novel approach, termed the FS-HMT method, aims to enhance accuracy. To validate the effectiveness of the proposed method, a simulation of a cantilever column was conducted using finite element software ANSYS 19.2. The numerical results demonstrate the capability of the proposed method to accurately predict curves with inflection points, yielding a maximum error of 1.1%. Subsequently, experimental verification was performed using a 1 m long spring steel sheet, showcasing an error of 4.9%, which is notably lower than that of the traditional FS framework. Our proposed modified FS framework exhibits improved accuracy, especially in scenarios involving inflection points. These findings underscore its potential as a valuable tool for enhanced shape sensing in practical applications.

Band-driven switching of magnetism in a van der Waals magnetic semimetal.

Magnetic semimetals form an attractive class of materials because of the nontrivial contributions of itinerant electrons to magnetism. Because of their relatively low-carrier-density nature, a doping level of those materials could be largely tuned by a gating technique. Here, we demonstrate gate-tunable ferromagnetism in an emergent van der Waals magnetic semimetal Cr3Te4 based on an ion-gating technique. Upon doping electrons into the system, the Curie temperature (TC) sharply increases, approaching near to room temperature, and then decreases to some extent. This non-monotonous variation of TC accompanies the switching of the magnetic anisotropy, synchronously followed by the sign changes of the ordinary and anomalous Hall effects. Those results clearly elucidate that the magnetism in Cr3Te4 should be governed by its semimetallic band nature.

Transverse momentum weighted Sivers asymmetries in SIDIS and Drell-Yan processes at COMPASS

We investigate the transverse momentum weighted Sivers asymmetries in the processes with transversely polarized proton target, including the PhTzMpsin⁡(ϕh−ϕS) weighted asymmetry in charged hadron production in semi-inclusive deeply inelastic scattering (SIDIS) and the qTMpsin⁡(ϕS) weighted asymmetry in π−p Drell-Yan process. These asymmetries can be expressed as the product of the transverse-moments of the transverse momentum dependent (TMD) parton distribution functions (PDFs) and fragmentation functions (FFs). Using the parametrization for the Sivers function of the proton, the unpolarized PDFs of proton and pion, and the unpolarized FF of charged hadron, we present the numerical calculation for weighted Sivers asymmetries in SIDIS and Drell-Yan processes at the kinematics of COMPASS. We find that our prediction for the SIDIS process is in agreement with the recent COMPASS measurement. Recent new high-statistics data of Sivers asymmetry measured in SIDIS process and Drell-Yan process from COMPASS favored the sign change of Sivers function. High-precision experimental data of weighted asymmetries are still needed to test the sign change property of the Sivers function between SIDIS and Drell-Yan processes and to constrain the sea quark Sivers function.

Fully Dynamic G3W2 Self-Energy for Finite Systems: Formulas and Benchmark.

Over the years, Hedin's GW self-energy has been proven to be a rather accurate and simple approximation to evaluate electronic quasiparticle energies in solids and in molecules. Attempts to improve over the simple GW approximation, the so-called vertex corrections, have been constantly proposed in the literature. Here, we derive, analyze, and benchmark the complete second-order term in the screened Coulomb interaction W for finite systems. This self-energy named G3W2 contains all the possible time orderings that combine 3 Green's functions G and 2 dynamic W. We present the analytic formula and its imaginary frequency counterpart, with the latter allowing us to treat larger molecules. The accuracy of the G3W2 self-energy is evaluated on well-established benchmarks (GW100, Acceptor 24, and Core 65) for valence and core quasiparticle energies. Its link with the simpler static approximation, named SOSEX for static screened second-order exchange, is analyzed, which leads us to propose a more consistent approximation named 2SOSEX. In the end, we find that neither the G3W2 self-energy nor any of the investigated approximations to it improve over one-shot G0W0 with a good starting point. Only quasi-particle self-consistent GW HOMO energies are slightly improved by addition of the G3W2 self-energy correction. We show that this is due to the self-consistent update of the screened Coulomb interaction, leading to an overall sign change of the vertex correction to the frontier quasiparticle energies.

Importance Sampling BRDF Derivatives

We propose a set of techniques to efficiently importance sample the derivatives of a wide range of Bidirectional Reflectance Distribution Function (BRDF) models. In differentiable rendering, BRDFs are replaced by their differential BRDF counterparts, which are real-valued and can have negative values. This leads to a new source of variance arising from their change in sign. Real-valued functions cannot be perfectly importance sampled by a positive-valued PDF, and the direct application of BRDF sampling leads to high variance. Previous attempts at antithetic sampling only addressed the derivative with the roughness parameter of isotropic microfacet BRDFs. Our work generalizes BRDF derivative sampling to anisotropic microfacet models, mixture BRDFs, Oren-Nayar, Hanrahan-Krueger, among other analytic BRDFs. Our method first decomposes the real-valued differential BRDF into a sum of single-signed functions, eliminating variance from a change in sign. Next, we importance sample each of the resulting single-signed functions separately. The first decomposition, positivization, partitions the real-valued function based on its sign, and is effective at variance reduction when applicable. However, it requires analytic knowledge of the roots of the differential BRDF, and for it to be analytically integrable too. Our key insight is that the single-signed functions can have overlapping support, which significantly broadens the ways we can decompose a real-valued function. Our product and mixture decompositions exploit this property, and they allow us to support several BRDF derivatives that positivization could not handle. For a wide variety of BRDF derivatives, our method significantly reduces the variance (up to 58× in some cases) at equal computation cost and enables better recovery of spatially varying textures through gradient-descent-based inverse rendering.

Modeling the Inflow of Exposed and Infected Migrants on the Dynamics of Malaria

Malaria is currently a life-threatening vector borne disease which is endemic in most of the developing and underdeveloped countries associated with poor health care systems. In this study, a host-vector mathematical model that takes into account the inflow of human migrants who have been exposed or infected with malaria is formulated and analysed. The reproduction number of the mosquito vector population is derived and used as a threshold quantity for determining the existence of the model trivial and realistic steady states. The Routh-Hurwitz criterion and some stability theorems of Metzler matrices are used to show that the realistic disease free equilibrium is both locally and globally asymptotically stable whenever the disease reproductive number is less than one. We derived an equation for the model endemic condition and used Descartes Rule of Sign Change to established the conditions for the model to admit one or three endemic equilibrium state(s). It is further shown that in the absence of inflow of exposed or infected migrants, the model admits a globally asymptotically unique endemic equilibrium when R0&gt;1 and two endemic equilibria when R0&lt;1. Our local sensitivity analysis revealed that the adults mosquito removal and biting rates were respectively the most significant contributing parameters to the spread of malaria. The numerical simulations results suggested that the exposed and infected immigrants have no significant impact on the dynamical behaviour of the model population sub-classes.

Direction-dependent conductivity in planar Hall set-ups with tilted Weyl/multi-Weyl semimetals.

We compute the magnetoelectric conductivity tensors in planar Hall set-ups, which are built with tilted Weyl semimetals (WSMs) and multi-Weyl semimetals (mWSMs), considering all possible relative orientations of the electromagnetic fields (EandB) and the direction of the tilt. The non-Drude part of the response arises from a nonzero Berry curvature in the vicinity of the WSM/mWSM node under consideration. Only in the presence of a nonzero tilt do we find linear-in-|B|terms in set-ups where the tilt-axis is not perpendicular to the plane spanned byEandB. The advantage of the emergence of the linear-in-|B|terms is that, unlike the various|B|2-dependent terms that can contribute to experimental observations, they have purely a topological origin, and they dominate the overall response-characteristics in the realistic parameter regimes. The important signatures of these terms are that they (1) change the periodicity of the response fromπto 2π, when we consider their dependence on the angleθbetweenEandB; and (2) lead to an overall change in sign of the conductivity depending onθ, when measured with respect to theB=0case.