Logarithmic Scale Research Articles

Fermion Disorder Operator at Gross-Neveu and Deconfined Quantum Criticalities.

The fermion disorder operator has been shown to reveal the entanglement information in 1D Luttinger liquids and 2D free and interacting Fermi and non-Fermi liquids emerging at quantum critical points (QCPs) [W. Jiang etal., arXiv:2209.07103]. Here we study, by means of large-scale quantum MonteCarlo simulation, the scaling behavior of the disorder operator in correlated Dirac systems. We first demonstrate the logarithmic scaling behavior of the disorder operator at the Gross-Neveu (GN) chiral Ising and Heisenberg QCPs, where consistent conformal field theory (CFT) content of the GN-QCP in its coefficient is found. Then we study a 2D monopole-free deconfined quantum critical point (DQCP) realized between a quantum-spin Hall insulator and a superconductor. Our data point to negative values of the logarithmic coefficients such that the DQCP does not correspond to a unitary CFT. Density matrix renormalization group calculations of the disorder operator on a 1D DQCP model also detect emergent continuous symmetries.

Anomalous fractal scaling in two-dimensional electric networks

Much of the qualitative nature of physical systems can be predicted from the way it scales with system size. Contrary to the continuum expectation, we observe a profound deviation from logarithmic scaling in the impedance of a two-dimensional LC circuit network. We find this anomalous impedance contribution to sensitively depend on the number of nodes N in a curious erratic manner and experimentally demonstrate its robustness against perturbations from the contact and parasitic impedance of individual components. This impedance anomaly is traced back to a generalized resonance condition reminiscent of Harper’s equation for electronic lattice transport in a magnetic field, even though our circuit network does not involve magnetic translation symmetry. It exhibits an emergent fractal parametric structure of anomalous impedance peaks for different N that cannot be reconciled with a continuum theory and does not correspond to regular waveguide resonant behavior. This anomalous fractal scaling extends to the transport properties of generic systems described by a network Laplacian whenever a resonance frequency scale is simultaneously present.

Level Of ART Adherence and associated factors among People Living with HIV in the Context of Early Antiretroviral therapy initiation In Wolaita Sodo Town, Ethiopia: Cross-sectional study.

Early antiretroviral therapy initiation is WHO recommendation for fasten viral suppression and for prevention of further viral transmission sexually. There is no evidence showing the level of adherence to antiretroviral therapy (ART) after initiation of the universal test and treat (UTT) strategy in Ethiopia, including study area. This study was aimed to determine the level of ART adherence and associated factors among HIV/AIDS patients in context of Universal test and treat strategy. A Health facility-based study was conducted on 352 people living with HIV who started their ART follow-up after application of universal test and treat strategy in Ethiopia from 15 April to 5 June 2020. Systematic random sampling method was used to select the study participants. Interviewer administered questionnaire was used to collect data and collected data were entered directly in to SPSS version 21 and analyzed. Both bivariate and multivariate logistic regression analyses were done. Strength and direction of association was determined by using AOR with 95%CI. The total 352 participants included the study. The overall level of adherence was 290 (82.4%). Commonly used ART regimen was TDF+3TC+EFV, 201(57.1%). In bivariate analysis, type of health institutions COR 2.934(1.388, 6.200), age level of 18-27 COR .357(.133, .959), current viral load in log scale COR= .357(.133, .959) and change of ART medication COR= 8.088(1.973, 33.165) were associated with medication adherence. Health institution type AOR = 2.615(1.147, 5.9600) and change of ART medication AOR= 7.267 (1.683, 31.384) were independent predictors of ART adherence. Low level of ART adherence was detected in this study. It was below the recommended good adherence standard and 90-90-90 target strategy. Therefore, patients should get adequate and comprehensive ART adherence counseling before initiation ART treatment and during the follow-up time.

Giant boundary layer induced by nonreciprocal coupling in discrete systems

Nonreciprocally coupled systems present rich dynamical behavior such as unidirectional amplification, fronts, localized states, pattern formation, and chaotic dynamics. Fronts are nonlinear waves that may connect an unstable equilibrium with a stable one and can suffer a convective instability when the coupling is nonreciprocal. Namely, a state invades the other one, and due to boundary conditions, the front stops and creates a boundary layer. Unexpectedly, in nonreciprocal coupled systems, we observe arbitrarily large boundary layers in the convective regime when the condition at the fixed edge does not match the equilibrium value. We analytically determine the boundary layer size using map iterations; these results agree with numerical simulations. On the other hand, if one of the boundary conditions matches the unstable equilibrium state, the boundary layer size diverges; however, due to the computer numerical truncation, it is finite in numerical simulations. Our result shows that, in nonreciprocally coupled systems, this mismatch in the boundary condition is relevant in controlling the boundary layer size, which exhibits a logarithm scaling with the mismatch value.

Global biomarkers of oxidative stress and fractures: a matched case-control study.

Evidence for a relationship between oxidative stress and osteoporotic fractures in humans is limited. Fluorescent oxidation products (FlOPs, excitation/emission wavelengths 320/420nm denoted FlOP_320; 360/420nm [FlOP_360]; and 400/475nm [FlOP_400]) are global biomarkers of oxidative stress, and reflect oxidative damage to proteins, phospholipids, and nucleic acids. We investigated the association between FlOPs and a recent osteoporotic fracture. We conducted a case-control study in a Chinese population aged 50 years or older. A recent osteoporotic fracture in the cases was confirmed by x-ray. Cases were matched with community-based non-fracture controls (1:2 ratio) for age (± 4 years) and sex. In addition, we conducted a sensitivity unmatched case-control study which included all fracture cases and all eligible non-fracture controls prior to matching. Plasma FlOPs were measured with a fluorescent microplate reader. We used unconditional logistic regression to analyze the association between FlOPs (per 1-SD increase in logarithmic scale) and fracture; odds ratios (OR) and 95% confidence intervals (95% CI) were reported. Forty-four cases and 88 matched controls (mean age: 68.2 years) were included. After covariate adjustment (i.e., body mass index, physical activity, and smoking), higher FlOP_360 (OR = 1.85; 95% CI = 1.03 - 3.34) and FlOP_400 (OR = 13.29; 95% CI = 3.48 - 50.69) levels, but not FlOP_320 (OR = 0.56; 95% CI = 0.27 - 1.15), were associated with increased fracture risk. Subgroup analyses by fracture site and unmatched case-control study found comparable associations of FlOP_360 and FlOP_400 with hip and non-hip fractures. Higher FlOP_360 and FlOP_400 levels were associated with increased risk of fracture, and this association was comparable for hip and non-hip fractures. Prospective studies are warranted to confirm this finding.

Channeling Quantum Criticality.

We analyze the effect of decoherence, modeled by local quantum channels, on quantum critical states and we find universal properties of the resulting mixed state's entanglement, both between system and environment and within the system. Renyi entropies exhibit volume law scaling with a subleading constant governed by a "g function" in conformal field theory, allowing us to define a notion of renormalization group (RG) flow (or "phase transitions") between quantum channels. We also find that the entropy of a subsystem in the decohered state has a subleading logarithmic scaling with subsystem size, and we relate it to correlation functions of boundary condition changing operators in the conformal field theory. Finally, we find that the subsystem entanglement negativity, a measure of quantum correlations within mixed states, can exhibit log scaling or area law based on the RG flow. When the channel corresponds to a marginal perturbation, the coefficient of the log scaling can change continuously with decoherence strength. We illustrate all these possibilities for the critical ground state of the transverse-field Ising model, in which we identify four RG fixed points of dephasing channels and verify the RG flow numerically. Our results are relevant to quantum critical states realized on noisy quantum simulators, in which our predicted entanglement scaling can be probed via shadow tomography methods.

Experimental estimates of germline mutation rate in eukaryotes: a phylogenetic meta-analysis.

Mutation is the ultimate source of all genetic variation, and over the last 10 years the ready availability of whole-genome sequencing has permitted direct estimation of mutation rate for many non-model species across the tree of life. In this meta-analysis, we make a comprehensive search of the literature for mutation rate estimates in eukaryotes, identifying 140 mutation accumulation (MA) and parent-offspring (PO) sequencing studies covering 134 species. Based on these data, we revisit differences in the single-nucleotide mutation (SNM) rate between different phylogenetic lineages and update the known relationships between mutation rate and generation time, genome size, and nucleotide diversity-while accounting for phylogenetic nonindependence. We do not find a significant difference between MA and PO in estimated mutation rates, but we confirm that mammal and plant lineages have higher mutation rates than arthropods and that unicellular eukaryotes have the lowest mutation rates. We find that mutation rates are higher in species with longer generation times and larger genome sizes, even when accounting for phylogenetic relationships. Moreover, although nucleotide diversity is positively correlated with mutation rate, the gradient of the relationship is significantly less than one (on a logarithmic scale), consistent with higher mutation rates in populations with smaller effective size. For the 29 species for which data are available, we find that indel mutation rates are positively correlated with nucleotide mutation rates and that short deletions are generally more common than short insertions. Nevertheless, despite recent progress, no estimates of either SNM or indel mutation rates are available for the majority of deeply branching eukaryotic lineages-or even for most animal phyla. Even among charismatic megafauna, experimental mutation rate estimates remain unknown for amphibia and scarce for reptiles and fish.

Association between sarcopenia and frailty in elderly patients with chronic kidney disease.

Frailty and sarcopenia are prevalent in chronic kidney disease (CKD) populations and could increase the risk for adverse health outcomes. Few studies assess the correlation between frailty, sarcopenia and CKD in non-dialysis patients. Therefore, this study aimed to determine frailty-associated factors in elderly CKD stage I-IV patients, expected to early identify and intervene in the frailty of elderly CKD patients. A total of 774 elderly CKD I-IV patients (>60years of age) recruited from 29 clinical centers in China between March 2017 and September 2019 were included in this study. We established a Frailty Index (FI) model to evaluate frailty risk and verified the distributional property of FI in the study population. Sarcopenia was defined according to the criteria of the Asian Working Group for Sarcopenia 2019. Multinomial logistic regression analysis was used to assess the associated factors for frailty. Seven hundred seventy-four patients (median age 67years, 66.0% males) were included in this analysis, with a median estimated glomerular filtration rate of 52.8mL/min/1.73m2 . The prevalence of sarcopenia was 30.6%. The FI exhibited a right-skewed distribution. The age-related slope of FI was 1.4% per year on a logarithmic scale (r2 =0.706, 95% CI 0.9, 1.8, P<0.001). The upper limit of FI was around 0.43. The FI was related to mortality (HR=1.06, 95% CI 1.00, 1.12, P=0.041). Multivariate multinomial logistic regression analysis showed that sarcopenia, advanced age, CKD stage II-IV, low level of serum albumin and increased waist-hip ratio were significantly associated with high FI status, while advanced age and CKD stage III-IV were significantly associated with for median FI status. Moreover, the results from the subgroup were consistent with the leading results. Sarcopenia was independently associated with an increased risk for frailty in elderly CKD I-IV patients. Patients with sarcopenia, advanced age, high CKD stage, high waist-hip ratio and low serum albumin level should be assessed for frailty.

Rock physics and machine learning comparison: elastic properties prediction and scale dependency

Rock physics diagnostics (RPD) established based upon the well data are used to deterministically predict elastic properties of rocks from measured petrophysical rock parameters. However, with the recent advances in statistical methods, machine learning (ML) can help to build a shortcut between raw well data and rock properties of interest. Several studies have reported the comparison of rock physics and machine learning methods for the prediction of rock properties, but the scale dependence of the ML models was never investigated. This study aims at comparing the results from rock physics and machine learning models for predicting elastic properties such as bulk density (ρb), P-wave velocity (Vp), S-wave velocity (Vs), as well as Poisson’s ratio (v) and acoustic impedance (Ip) in a well from the Gulf of Mexico (GOM) in two different scale scenarios: the well log and seismic scales. The well data under examination was split into training and testing subsets to optimize and test the developed ML models. The RPD approach was also used to validate and compare the accuracy of predicted elastic properties. Backus averaging was later applied to upscale the well data to the seismic scale to examine the scale dependence and prediction accuracy of aforementioned physics-driven and data-driven approaches. Results show that RPD and ML methods provided consistent results at both well log and seismic scales, suggesting the scale independence of both approaches. Moreover, ML models showed better estimation of rock properties due to their “apparent” match with measured data at both scales compared to the RPD approach where a significant mismatch between measured and predicted rock properties was found in the reservoir section of the well. However, by conducting further quality control of the sonic data, it was found that the measured Poisson’s ratio was extremely high in the gas-saturated interval. Hence, the prediction from ML models in this particular case cannot be trusted as ML models were trained based on poor-quality well data with non-realistic Vs and v values. Such an issue, however, could be identified and corrected using RPD as presented in this study. We demonstrate the importance of incorporating domain knowledge, i.e., rock physics, to check data quality and validate results from data-driven models.

Effect of straight riblets of the underlying surface on wall bounded flow drag

Direct numerical simulations of thin, straight riblets were conducted to investigate the physical mechanisms involved when the inertial effects within the ribs become important. The main parameter that we assess here is the ribs’ height to spacing ratio (a=h/s). In all cases, ‘k’-type behaviour was observed despite the absence of the pressure drag component. This trend also refers to the destruction of the near-wall cycles and was indicated by the shortening of Reynolds stress structures, mimicking the flows over rough walls. Closely-packed ribs with large h/s have a tendency to generate Kelvin–Helmholtz (KH) like structures at the tips, inducing large pressure fluctuations. Conversely, sparser ribs with low h/s trigger the formation of large mean secondary flows that suppress the pressure fluctuations. We further split the drag contribution of these distinct flow features by decomposing the roughness function into the dispersive and the Reynolds-stress terms. This analysis concludes that the fully-rough (logarithmic) scaling within the drag-increasing regime is transitional, and as the Reynolds number increases, deviates to a more gradual power-law scaling due to the drag increasing mechanism of streamwise aligned secondary motions.

Incorrect use of meta-analytic procedures.

Sir, Maggu, et al.[1] described a systematic review and meta-analysis of the prevalence of depression and anxiety in children and adolescents during the COVID-19 pandemic. They stated in their abstract and text that the pooled prevalence of depression and anxiety was 27% and 25%, respectively. Given the importance of the subject, the paper was taken up for discussion in eJCIndia, a national network of nearly 900 psychiatric faculty, residents, and practitioners across the country.[2] The discussion in eJCIndia centered around one critical and other lesser points; these are briefly presented. The critical point is that the forest plots, which are key to the meta-analysis, were generated for rate ratios. The rate ratio is the wrong choice of the statistic when the outcome of interest is a prevalence because a rate ratio compares prevalences in two groups; in this meta-analysis, no groups were intended to be compared. If the wrong method was employed for meta-analysis, the results and hence the conclusions may be wrong. Other issues also need to be considered. For example, the horizontal axis in the forest plots was constructed along a logarithmic scale; more correctly, when the outcome is a prevalence, it should have been constructed along an arithmetic scale. Finally, there are discrepancies between the pooled values stated in the abstract and text (27% and 25%) and those evident in the forest plot (26% and 23%). Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Probing the energy levels of organic bulk heterojunctions by varying the donor content

The performance of organic solar cells is strongly governed by the properties of the photovoltaic active layer. In particular, the energetics at the donor (D)–acceptor (A) interface dictate the properties of charge transfer (CT) states and limit the open-circuit voltage. More generally, energetic landscapes in thin films are affected by intermolecular, e.g., van der Waals, dipole, and quadrupole, interactions that vary with D:A mixing ratio and impact energy levels of free charges (ionization energy, electron affinity) and excitons (singlet, CT states). Disentangling how different intermolecular interactions impact energy levels and support or hinder free charge generation is still a major challenge. In this work, we investigate interface energetics of bulk heterojunctions via sensitive external quantum efficiency measurements and by varying the D:A mixing ratios of ZnPc or its fluorinated derivatives and C60. With increasing donor fluorination, the energetic offset between FxZnPc and C60 reduces. Moving from large to low offset systems, we find qualitatively different trends in device performances with D:C60 mixing ratios. We rationalize the performance trends via changes in the energy levels that govern exciton separation and voltage losses. We do so by carefully analyzing shifts and broadening sEQE spectra on a linear and logarithmic scale. Linking this analysis with molecular properties and device performance, we comment on the impact of charge–quadrupole interactions for CT dissociation and free charge generation in our D:C60 blends. With this, our work (1) demonstrates how relatively accessible characterization techniques can be used to probe energy levels and (2) addresses ongoing discussions on future molecular design and optimal D–A pairing for efficient CT formation and dissociation.

Serum vitamin B12 levels and response to immunotherapy.

e14542 Background: Underlying metabolic pathways have a role in regulation of response to cancer immunotherapy. Due to its immunomodulatory properties, we sought to investigate the relationship between elevated serum vitamin B12 (VitB12) and survival among individuals with cancer treated with immune checkpoint inhibitors. Methods: Data from a retrospective chart review were used to identify patients with advanced cancer initiating anti-neoplastic treatment and a concomitant VitB12 measurement (elevated: &gt; 820 ng/L), between 1/2010-1/2022 at our institution. Patients on immunotherapy (IO) and other regimens (control) were compared using Mann-Whitney test for continuous variables, and Chi-square test or Fisher's test for categorical variables. Multivariate Cox regression models were used to assess the effect of VitB12 levels on overall survival (OS) and progression free survival (PFS), with adjustment for potential confounders. Results: A total of 501 patients were included (control, n = 408; IO, n = 93). Groups were well balanced for treatment line (first line, 91.4% vs. 94%), VitB12 levels (elevated, 29.9% vs. 23.7%; mean, 762.4 ng/L vs. 687.6 ng/L) and liver function tests. Cancer diagnoses differed between groups (most common, gastrointestinal vs. lung, p &lt; 0.001). Multivariate analysis revealed that high VitB12 was negatively associated with OS in both groups (control: hazard ratio, HR 1.4, 95% CI 1.01-1.96, p = 0.04; IO: HR 2.74 as sum of linear baseline and interaction effects, in log scale), as were age (HR 1.03, 95% CI 1.02-1.04, p &lt; 0.01), male gender (HR 0.66, 95% CI 0.50-0.88, p &lt; 0.01), and neutrophil to lymphocyte ratio (NLR) (HR 1.05, 95% CI 0.48-0.99, p = 0.01). However, the only negative prognostic factor for PFS was VitB12 in the IO group alone (calculated HR 8.34). No association was observed with patient and cancer characteristics, other laboratory values, chemotherapy (p = 0.3) or biologic therapy (p = 0.8). Mean follow-up in the control and IO groups was 93 vs 54 weeks (OS), and 22 vs 33 weeks (PFS), respectively. Conclusions: Elevated VitB12 levels were negatively associated with response to immune checkpoint inhibitors, independently of other prognostic factors such as age, cancer type, treatment line and NLR. In addition to a direct role in cellular immunity, VitB12 is involved in gut microbiota balance, which in turn affects host immune responses – suggesting a possible immune-metabolic interplay. Further research is needed to elucidate the metabolic regulators of response to immunotherapy and potential strategies of intervention, in order to rationalize and broaden its clinical utility.

Higher-order turbulence statistics and multiscale characterization of morphodynamics in a riverbank section with an upstream mining pit

Channel dredging has become a common phenomenon across several fluvial systems. Pits dredged in the riverbank can influence the downstream turbulence and affect the bank slope and central channel morphodynamics. Erodible bed experiments were conducted in a laboratory flume having a riverbank cross section with three different bank slopes, i.e., 25°, 31°, and 40° with and without a mining pit. Flow over the bank slope and near the bank toe was most affected by the pit excavation at the channel upstream. Turbulence levels were amplified within the flow over the slope and near the bank toe. The logarithmic scaling range of higher-order fluctuations at the bank toe is greater for with pit case. The complex interaction of simultaneous processes like pit migration, sliding failure and bank erosion, and fluvial erosion was studied at multiple length scales and time scales. A wavelet cross correlation analysis was used to calculate the celerity of bedform migration at the bank toe along the flow. Statistical celerity of bedforms with smaller scales (up to 15 mm length scales) is significantly higher due to pit interaction. The study reveals that instream mining has notable effects on the inherent nature of higher-order turbulence statistics, especially near the bank slope and toe, as well as the multiscale morphological structures.

A Practical Approach of Probabilistic Seismic Hazard Analysis for Vector IMs Regarding Mainshock with Potentially Largest Aftershock

ABSTRACT Seismic hazard and risk may be underestimated if aftershocks are ignored within the traditional probabilistic seismic hazard analysis (PSHA). In this study, a practical approach is proposed to calculate the mean annual rate of the joint exceedance of different ground motion vector intensity measures (IMs) for mainshocks and their potentially largest aftershock. The proposed approach is built based on an indirect vector-valued PSHA framework, which was originally used to compute the joint hazard of multiple IMs for mainshocks. Within the proposed approach, the overall hazard caused by mainshock-aftershock scenarios is calculated by including two key components, namely: 1) the occurrence rate of a given hazard level of mainshock as calculated by the standard PSHA; and 2) the occurrence probability of a given hazard level of aftershock conditioned on the mainshock, which is calculated by establishing the joint distribution of the IMs for both mainshocks and aftershocks using the Copula theory. Based on 662 groups of mainshock-aftershock ground motions from 13 earthquake events in the NGA-West2 database, the empirical joint probability distribution model between the peak ground accelerations of mainshocks and aftershocks (i.e. PGA MS and PGA AS) is developed. The Clayton Copula function is calibrated as the optimal choice and the marginal distributions of PGA MS or PGA AS could be properly modelled using the generalized extreme value distributions. The proposed approach is implemented to construct the joint hazard surface regarding both PGA MS and PGA AS for a hypothetical site. The results indicate that using different types of copula functions and marginal distributions of PGA MS and PGA AS has a noticeable impact on the final joint hazard level. Moreover, a coarse assumption that PGA MS and PGA AS follow a joint Gaussian distribution in the logarithm scale would lead to considerable bias in the mainshock-aftershock joint hazard especially at low mean annual rates of exceedance.

A Strong-Type Furstenberg–Sárközy Theorem for Sets of Positive Measure

For every beta in (0,infty ), beta ne 1, we prove that a positive measure subset A of the unit square contains a point (x_0,y_0) such that A nontrivially intersects curves y-y_0 = a (x-x_0)^beta for a whole interval Isubseteq (0,infty ) of parameters ain I. A classical Nikodym set counterexample prevents one to take beta =1, which is the case of straight lines. Moreover, for a planar set A of positive density, we show that the interval I can be arbitrarily large on the logarithmic scale. These results can be thought of as Bourgain-style large-set variants of a recent continuous-parameter Sárközy-type theorem by Kuca, Orponen, and Sahlsten.

Flame Retardancy Index (FRI) for Polymer Materials Ranking.

In 2019, we introduced Flame Retardancy Index (FRI) as a universal dimensionless index for the classification of flame-retardant polymer materials (Polymers, 2019, 11(3), 407). FRI simply takes the peak of Heat Release Rate (pHRR), Total Heat Release (THR), and Time-To-Ignition (ti) from cone calorimetry data and quantifies the flame retardancy performance of polymer composites with respect to the blank polymer (the reference sample) on a logarithmic scale, as of Poor (FRI ˂ 100), Good (100 ≤ FRI ˂ 101), or Excellent (FRI ≥ 101). Although initially applied to categorize thermoplastic composites, the versatility of FRI was later verified upon analyzing several sets of data collected from investigations/reports on thermoset composites. Over four years from the time FRI was introduced, we have adequate proof of FRI reliability for polymer materials ranking in terms of flame retardancy performance. Since the mission of FRI was to roughly classify flame-retardant polymer materials, its simplicity of usage and fast performance quantification were highly valued. Herein, we answered the question "does inclusion of additional cone calorimetry parameters, e.g., the time to pHRR (tp), affect the predictability of FRI?". In this regard, we defined new variants to evaluate classification capability and variation interval of FRI. We also defined the Flammability Index (FI) based on Pyrolysis Combustion Flow Calorimetry (PCFC) data to invite specialists for analysis of the relationship between the FRI and FI, which may deepen our understanding of the flame retardancy mechanisms of the condensed and gas phases.

Logarithmic scaling of higher-order temperature moments in the atmospheric surface layer

A generalized logarithmic law for high-order moments of homogeneous passive scalars is proposed for turbulent boundary layers. This law is analogous to the generalized log law that has been proposed for high-order moments of the turbulent longitudinal velocity and is derived by combining the random sweeping decorrelation hypothesis with a spectral model informed by the attached eddy hypothesis. The proposed theory predicts that the high-order moments of passive scalar fluctuations within the inertial sublayer will vary logarithmically with wall-normal distance (z), and is evaluated using high frequency time-series measurements of temperature and streamwise velocity fluctuations obtained in the first meter of the atmospheric surface layer (ASL) under near-neutral thermal stratification. The logarithmic dependence with z within the inertial sublayer is observed in both the air temperature and velocity moments, with good agreement to the predictions from the proposed theory. Surprisingly, the proposed theory appears to be as, if not more, valid for transported passive scalars than for the longitudinal velocity.

Atmospheric Turbulent Characteristics Under Summer Shamal in Coastal Qatar

AbstractSummer Shamal, a strong low‐level northwesterly wind in the Middle Eastern, is the major trigger for dust storm activity with a broad impact on regional transport and human safety. However, near‐ground turbulent mixing analysis under Shamal is still rare due to the lack of available high frequency data. The present study explores the near‐surface turbulence characteristics under summer Shamal, compared with those of non‐Shamal, in the coastal region of Qatar (26.08°N, 51.36°E). The results show that Shamal prevents the development of summer sea breezes in the Persian Gulf. A “Shamal day” (SD) is commonly defined as a day with a strong, continuous, north‐northwesterly wind. Compared to non‐Shamal days (NSD), SDs are characterized by higher surface sensible heat flux and turbulent kinetic energy (TKE) with lower humidity, especially around noon time. At night, the wind turbulence energy is contained in smaller eddies for SD due to the more stable atmospheric conditions. The streamwise velocity spectra analysis displays a power‐law trend with a coefficient of −1.53 as compared to the traditional Kolmogorov −1.67 (−5/3) power law, indicating a higher TKE dissipation rate for SD. The smaller scatter of the normalized TKE dissipation rate observed for SD is related to lower streamwise turbulence intensity. A Weibull distribution is observed for probability distribution of TKE dissipation rate under SD in log scale for both stable and unstable conditions. This distribution for TKE dissipation rate is different than the results from other field measurements due to Shamal.

Association between Triglyceride-Glucose Index and Early Neurological Outcomes after Thrombolysis in Patients with Acute Ischemic Stroke.

The triglyceride-glucose (TyG) index is a novel biomarker of insulin resistance which might plausibly influence endogenous fibrinolysis and thus early neurological outcomes in patients with acute ischemic stroke (AIS) treated with intravenous thrombolysis using recombinant tissue-plasminogen activator. We included consecutive AIS patients within 4.5 h of symptom onset undergoing intravenous thrombolysis between January 2015 and June 2022 in this multi-center retrospective observational study. Our primary outcome was early neurological deterioration (END), defined as ≥2 (END2) or ≥ 4 (END4) National Institutes of Health Stroke Scale (NIHSS) score worsening compared to the initial NIHSS score within 24 h of intravenous thrombolysis. Our secondary outcome was early neurological improvement (ENI), defined as a lower NIHSS score at discharge. TyG index was calculated using the log scale of fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2. We evaluated the association of END and ENI with TyG index using a logistic regression model. A total of 676 patients with AIS were evaluated. The median age was 68 (Interquartile range, IQR (60-76) years old), and 432 (63.9%) were males. A total of 89 (13.2%) patients developed END2, 61 (9.0%) patients developed END4, and 492 (72.7%) experienced ENI. In multivariable logistic regression analysis, after adjustment for confounding factors, TyG index was significantly associated with increased risks of END2 (categorical variable, vs. lowest tertile, medium tertile odds ratio [OR] 1.05, 95% confidence interval, CI 0.54-2.02, highest tertile OR 2.94, 95%CI 1.64-5.27, overall p < 0.001) and END4 (categorical variable, vs. lowest tertile, medium tertile OR 1.21, 95%CI 0.54-2.74, highest tertile OR 3.80, 95%CI 1.85-7.79, overall p < 0.001), and a lower probability of ENI (categorical variable, vs. lowest tertile, medium tertile OR 1.00, 95%CI 0.63-1.58, highest tertile OR 0.59, 95%CI 0.38-0.93, overall p = 0.022). Increasing TyG index was associated with a higher risk of END and a lower probability of ENI in patients with acute ischemic stroke treated with intravenous thrombolysis.