Change In Slope Research Articles

The Correlation Between Gender, Age, Curvature, and Symptom-related Changes in C6 and C7 Slope in 10,000 Subjects.

A cross-sectional analysis of 10,000 cervical spine X-rays. This study investigates the variations in C6S and C7S across demographic factors (gender, age, cervical curvature, symptoms) and explores their correlation. Additionally, machine learning models are applied to improve the accuracy of C7S prediction. The C7S is crucial for assessing cervical balance but is often limited by visibility issues. This study uses a large sample to validate the feasibility of the C6S as a substitute for C7S across diverse populations with varying ages, genders, symptoms, and cervical curvatures. A retrospective study was conducted on 10,000 subjects who underwent cervical sagittal X-ray imaging. Four orthopedic specialists labeled key points, which were cross-validated, and an algorithm was then used to measure C6S and C7S. Pearson correlation coefficients were calculated to assess the relationship between C6S and C7S, and linear regression derived a predictive equation for C7S. Various machine learning models were compared to improve C7S prediction accuracy. The average angles for C6S and C7S were 15.4° (16.8° in males, 14.7° in females) and 19.1° (21.1° in males, 18.2° in females), respectively, with C7S generally larger than C6S, except in Sigmoid 1 curvature. Males exhibited higher values for both C6S and C7S, and both slopes increased after age 20. Both angles increased significantly with age from 20 to 90 years. A strong positive correlation was found between C6S and C7S (r>0.75, P<0.001), confirmed by linear regression (R²=0.688). Among the machine learning models, both Ridge Regression and Linear Regression performed better than the others, with R²=0.855 in predicting C7S. The strong correlation between C6S and C7S suggests that C6S can substitute for C7S when visibility is limited. Machine learning models further enhance prediction accuracy, demonstrating promising clinical potential.

The association of public health interventions regarding both infant sleep position and pertussis immunization with sudden infant death syndrome rates: an ecological study.

Infections may play a role in the etiology of sudden infant death syndrome (SIDS), with Bordetella pertussis being a potential agent. The objective was to analyze the association of SIDS and infant pertussis hospitalization rates over time, comparing a previously unvaccinated population (West Germany) versus a predominantly vaccinated population (East Germany). We calculated SIDS rates per 1000 live births per state. Live births and SIDS were available from 1980 onwards for the West German states and from 1991 onwards for the East German states. We applied interrupted time series (ITS) analyses to investigate the role of two public health interventions in 1991 (West Germany) and in 2000 (West and East Germany), respectively. Infant pertussis hospitalizations were available for five West German and three East German states between 1994 and 2019. We used multilayer and multivariate correlation analyses to determine the correlation between SIDS and pertussis hospitalization rates, including Pearson correlation test and vector autoregressive (VAR) analysis. In West Germany, the average annual SIDS rate (per 1000 live births) increased from 1.08 in 1980 to 1.68 in 1991, before declining to 1.18 in 1992 and subsequently to 0.10 in 2020. In East Germany, the average annual SIDS rate (per 1000 live births) decreased from 0.79 in 1991 to 0.12 in 2020. The results of the ITS model indicated a significant change in both level and slope at the 1991 interventions (West Germany) and in slope at the 2000 interventions (West and East Germany). The correlation coefficients between SIDS and infant pertussis hospitalization rates were 0.69 (95% CI [confidence interval]0.41, 0.85; p < 0.001) in West Germany, and 0.41 (95% CI 0.03, 0.69; p = 0.037) in East Germany. The correlation decreased during later periods (2000-2019, 2010-2019), particularly in East Germany. The results of the VAR analysis corroborated the findings of the main analyses. SIDS and infant pertussis hospitalization rates were correlated in both West and East Germany. Further studies - including improved diagnostic assessment of pertussis - seem warranted. Not applicable.

Steady Shear Rheology and Surface Activity of Polymer-Surfactant Mixtures

Understanding the interactions between polymers and surfactants is critical for designing advanced fluid systems used in applications such as enhanced oil recovery, drilling, and chemical processing. This study examines the effects of five surfactants: two anionic (Stepanol WA-100 and Stepwet DF-95), one cationic (HTAB), one zwitterionic (Amphosol CG), and one non-ionic (Alfonic 1412-3 Ethoxylate), on the steady shear rheology and surface activity of two polymers, namely cationic hydroxyethyl cellulose based polymer (LR-400) and anionic polyacrylamide based polymer (Praestol 2540TR). The polymer-surfactant solutions behave as shear-thinning fluids and follow the power-law model. Anionic surfactants exhibit a strong effect on the rheology of cationic polymer LR-400 solution. The consistency index rises sharply with the increase in surfactant concentration. Also, the solutions become highly shear-thinning with the increase in surfactant concentration. The effects of other surfactants on the rheology of cationic polymer solution are small to modest. None of the surfactants investigated exhibit a strong influence on the rheology of anionic polymer Praestol 2540TR. Only weak to modest effects of surfactants are observed on the rheology of anionic polymers. The surface tension of the polymer-surfactant solution decreases with the increase in surfactant concentration. Zwitterionic surfactant Amphosol CG is found to be most effective in reducing the surface tension at a given concentration in ppm. This surfactant also raises the electrical conductivity of the solution to the largest extent. From the changes in slope of surface tension versus surfactant concentration plots, the approximate values of critical aggregation concentration (CAC) and polymer saturation point (PSP) are estimated.

P-1629. Reduction in Clostridioides difficile Over-diagnosis Following Suppression of C. difficile Target from Multiplex Molecular Stool Assay in a Pediatric Healthcare System

Abstract Background Clostridioides difficile testing by polymerase chain reaction (PCR) does not differentiate asymptomatic colonization from infection, and children are frequently colonized with toxigenic strains of C. difficile. Over-diagnosis of C. difficile infections can lead to adverse patient outcomes and poorer quality metrics for hospitals.Figure 1:C. difficile PCR orders following change in GI PCR Panel, Interrupted Time Series Methods In January 2023 our pediatric health system enacted multimodal changes to the electronic ordering of stool tests for C. difficile and other gastrointestinal pathogens. A multiplex PCR test for stool was updated to suppress testing for toxigenic C. difficile. The only remaining method to test for C. difficile by PCR in house was a C. difficile toxin gene specific PCR. Additionally, appropriate clinical criteria with a hard stop were added to the C. difficile PCR order (all of: no laxatives in the past 24 hours, at least 3 liquid stools in the past 24 hours, at least one risk factor for C. difficile infection, and patient at least one year old). If providers still sought C. difficile testing without meeting these criteria, infectious disease specialist approval was required. We analyzed the effect of this intervention using interrupted time series analysis and pre-post aggregate rates from January 2019 through February 2024.Figure 2:C. difficile positive rate following change in GI PCR Panel, Interrupted Time Series Results There were 4426 stool PCR tests performed for C. difficile in the pre-intervention period and 622 in the post-intervention period. The mean (± sd) age of those tested was 7.8 years (± 6.1 years). After the intervention, there was an immediate 61% decrease in C. difficile testing incidence (95% CI [53% - 67%], Figure 1) and 51% decrease in C. difficile diagnosis incidence (95% CI [26% - 67%], Figure 2). There was no significant immediate change or change in slope in the C. difficile antibiotic treatment incidence or HFO C. difficile incidence, but there was a trend towards lower rates of healthcare facility onset C. difficile after the change (aggregate rate 4.13 per 10,000 non-NICU patient-days prior to intervention vs. 3.39 after, P = .28). Conclusion Removing C. difficile from multiplex PCR assays and adding required clinical criteria to the electronic order reduces the number of C. difficile tests and diagnoses in a pediatric health system. Disclosures Laura Filkins, PhD, Avsana Labs: Board Member|Avsana Labs: Stocks/Bonds (Private Company)|Biofire Diagnostics: Grant/Research Support

Association of Menopause With Functional Outcomes and Disease Biomarkers in Women With Multiple Sclerosis.

The impact of menopause on the brain is not well understood. Hormonal changes, including puberty and pregnancy, influence the onset and course of multiple sclerosis (MS). After menopause, a worsening of MS disease trajectory measured on the clinician-rated Expanded Disability Status Scale (EDSS) was reported in some, but not all, studies. Evaluating the association between menopause and more objective measures of CNS injury is warranted. This study sought to assess the trajectory of objective functional outcomes and disease biomarkers in women with MS before and after menopause in a longitudinal prospective observational cohort. Data were collected prospectively from a longitudinally followed MS cohort, including the performance-based Multiple Sclerosis Functional Composite (MSFC) as the primary functional outcome and the paraclinical marker of neuronal injury serum neurofilament light chain (sNfL) as the primary biomarker outcome. Outcomes were analyzed using segmented linear mixed model regressions adjusted for age, BMI, and tobacco use, with a change in slope at the time of menopause, as the a priori inflection point. One hundred and eighty-four postmenopausal women met inclusion criteria. Participants were followed for a median of 13 years (interquartile range [IQR] = 4, range: 1-17). The median MS duration was 24 years (IQR = 13, range: 3-64), and the median EDSS score was 2.5 (IQR = 2, range: 0-8). The median age at natural menopause was 50 years (IQR = 5, range: 33-60); 17% of participants used any systemic menopausal hormone therapy. Menopause reflected an inflection point in MSFC worsening (slope difference 0.08, 95% CI 0.01, 0.14, p = 0.0163) and increase in serum neurofilament light chain (slope difference -0.95, 95% CI -1.74 to -0.16, p = 0.0194) while the opposite was found for EDSS (slope difference 0.05, 95% CI 0.01-0.09, p = 0.0200). Findings remained significant after adjustment for multiple covariates. When using additional nonlinear regression modeling, similar inflection points were found (within 3 years of the final menstrual period) for sNfL and EDSS but not MSFC. The menopausal transition may represent an inflection in accumulation of neuronal injury and functional decline in MS.

Effects of Visitation Restriction on Antipsychotic Drug Use Among Nursing Home Residents With ADRD During the COVID-19 Pandemic.

To estimate the immediate and long-term effects of a visitor restriction policy on antipsychotic use in nursing home (NH) residents with Alzheimer's disease and related dementias (ADRD) during COVID-19. A repeated cross-sectional study time series analysis was conducted using NH electronic health records (EHRs) from January 1, 2020, to December 31,2021. A large, multistate sample of NH residents living with ADRD. We calculated weekly changes in facility-level prevalence of antipsychotic use using interrupted time series (ITS) to compare level and slope changes in antipsychotic use before, during, and after NH visitation restrictions. Generalized linear models with generalized estimating equations, logit link, binomial distribution, and AR-1 correlation structure were used for all ITS analyses. Final models were stratified by long- and short-stay residents and adjusted for NH-level covariates including resident demographics, clinical diagnoses, and nurse staffing. We observed more than 8500 long-stay and 2700 short-stay NH residents with ADRD. Among long-stay residents, the weekly prevalence of antipsychotic use increased from 18.9% as of January 7, 2020, to 24.9% by December 31, 2021. For short-stay residents, antipsychotic use increased from 21.1% to 26.6% over this same window. The ITS analysis showed no meaningful changes in the relative rate of change in antipsychotic use during and after visitor restrictions, relative to pre-policy trends. The Centers for Medicare and Medicaid Services visitation restriction policy had no meaningful impact on antipsychotic use among NH residents with ADRD. However, antipsychotic use increased over time for both long- and short-stay residents and remained above pre-pandemic levels by the end of 2021. Our findings emphasize the potential for increased reliance on pharmacotherapy to manage resident symptoms during public health emergencies. Future infection control efforts should prioritize safe interpersonal care delivery and consider policies that improve vigilance of medication utilization changes among high-risk populations.

Prescription Stimulant Dispensing to US Children: 2017-2023.

To evaluate changes in prescription stimulant dispensing to children aged 5to 17years associated with the COVID-19 pandemic and the shortage of immediate-release mixed amphetamine salts (Adderall), which was announced in October 2022. We analyzed the 2017to 2023IQVIA Longitudinal Prescription Database, which captures 92% of US prescriptions. Using an interrupted time series design, we evaluated level and slope changes in the monthly stimulant-dispensing rate (number of children with stimulant dispensing per 100 000children) in March 2020and October 2022. In March 2020, the monthly stimulant-dispensing rate to children declined -454.9children per 100 000 (95%CI, -572.6to -337.2), an 18.8% decrease relative to January 2017. After March 2020, this rate increased to 12.7children per 100 000per month (95%CI, 6.6-18.8). In October 2022, there was no level change (-39.7children per 100 000; 95%CI, -189.9to 110.5) or slope change (-12.1children per 100 000per month; 95%CI, -27.5to 3.3), although estimates were negative. During October 2022, there was a level decrease in the monthly dispensing rate for immediate-release mixed amphetamine salts and a level increase in the monthly dispensing rate for dexmethylphenidate. Stimulant dispensing to children declined after the pandemic began. Dispensing may also have declined after October 2022, but estimates were not significant, partly because decreased dispensing of immediate-release mixed amphetamine salts was offset by increased dispensing of other stimulants. Findings suggest the shortage may have prompted children to switch to alternative stimulants. Future research should evaluate whether any switches led to adverse events.

Distribution of airway pressure opening in the lungs measured with electrical impedance tomography (POET): a prospective physiological study

BackgroundIn patients with acute hypoxemic respiratory failure (AHRF) under mechanical ventilation, the change in pressure slope during a low-flow insufflation indicates a global airway opening pressure (AOP) needed to reopen closed airways and may be used for titration of positive end-expiratory pressure.ObjectivesTo understand 1) if airways open homogeneously inside the lungs or significant regional AOP variations exist; 2) whether the pattern of the pressure slope change during low-flow insufflation can indicate the presence of regional AOP variations.MethodsUsing electrical impedance tomography, we recorded low-flow insufflation maneuvers (< 10 L/min) starting from end-expiratory positive pressure 0–5 cmH2O. We measured global (AOPglobal) and regional AOPs from pressure-impedance curves in the four different lung quadrants, and compared AOPglobal with the highest quadrantal AOP (AOPhighest). We categorized the slope change of the low-flow inflation pressure–time curve into three patterns: no change, progressive change, abrupt change.ResultsAmong the 36 patients analyzed, 9 (25%) had AOPglobal ≥ 5 cmH2O whereas 19 (53%) exhibited regional AOPhighest ≥ 5 cmH2O. AOPglobal was on average similar to AOP of the upper right quadrant (P = 0.182) but was lower than AOPs of the other three quadrants (P < 0.01 of each). AOPglobal was significantly lower than AOPhighest: 3.0 [2.0–4.3] vs. 5.0 [2.8–8.3] cmH2O, P < 0.001. AOP was higher in the dependent than the non-dependent ventilated lung (4.0 [2.0–6.3] vs. 3.0 [2.0–5.0] cmH2O, P < 0.001). Seventeen (47%) patients exhibited a ‘progressive change’ pattern in the pressure–time curve. These patients had a larger difference between AOPhighest and AOPglobal (3.0 [2.0–4.0] cmH2O with a maximum of 8 cmH2O) compared to the other two patterns: 1.0 [0–1.0] cmH2O in ‘no change’ , P < 0.001 and 1.0 [0–2.0] cmH2O in ‘abrupt change’ , P = 0.003.ConclusionAOPglobal mostly reflects the lowest opening pressure in the lung and frequently underestimates the highest regional AOP in mechanically ventilated patients with AHRF. A progressive slope change during the low-flow pressure–time curve indicates the presence of several and higher regional AOPs.Trial registrationClinicaltrials.gov, NCT 05825534 (registered, April 24th, 2023), retrospectively registered.Graphical abstract

Impact of an Oregon health policy aimed at strengthening adolescent linkage to outpatient mental health care from the emergency department.

Oregon introduced a state policy, HB 3090, on October 6, 2017, which increased requirements on emergency departments (EDs) to improve transitions to outpatient mental health care. The objective of this study was to examine the policy's impact among low-income adolescent patients who face severe barriers to follow-up. This was a retrospective cohort study of visits by Medicaid enrollees ages 14-18 presenting to any Oregon ED for a mental health concern between January 1, 2016, and December 31, 2019. We calculated standardized mean differences and used interrupted time series models to evaluate the association of HB 3090 with 14-day mental health follow-up, in-ED services, and inpatient admissions, adjusting for gender, race/ethnicity, primary language, and calendar months. Among 26,071 adolescent mental health-related ED visits, we found an estimated increase of 3.63 percentage points (pp; 95% confidence interval [CI] 0.27 to 6.99) in the adjusted probability of a 14-day outpatient mental health claim postpolicy. However, this effect was attenuated over time, with a slope change of -0.25 pp (95% CI -0.5 to 0) for each month thereafter. The probability of receiving mental health services in the ED or inpatient admission did not change in association with the policy. There was a small increase in short-term outpatient mental health visits after the policy, but the association weakened over time, and other key outcomes did not change. Putting pressure on EDs to perform better in this area is likely to be a minimally effective strategy without accompanying strengthening of mental health resources.

Research on the Correlation Mechanism Between Complex Slopes of Mountain City Roads and the Real Driving Emission of Heavy-Duty Diesel Vehicles

This research proposed the method of using cumulative positive and negative elevation increment indicators based on road segment to identify the slope characteristics of mountain city roads. Furthermore, it proposed the adoption of these indicators, combined with driving dynamics and emission theory, to analyze the correlation mechanism between the road slope and the actual driving fuel consumption and emissions. Three routes with different slope characteristics were selected in the mountain city of Chongqing, and six road driving tests were conducted using a Class N2 heavy-duty diesel vehicle. Finally, a comprehensive and in-depth study on fuel consumption and emission characteristics was carried out. The results show that the cumulative positive and negative elevation increment indicators based on road segment can correctly identify the complex slope characteristics of mountain city roads. Moreover, using the above indicators, the research method based on the theory of driving dynamics and emission successfully revealed the correlation mechanism between the slope of mountain city roads and the fuel consumption and emissions. Overall, the changes in fuel consumption factor and pollutants CO, NOX, and PN are positively correlated with the change in slope. The increase in slope leads to a rise in load, thereby increasing the required power, fuel consumption, and rich combustion conditions, ultimately leading to an increase in pollutants. It should be noted that driving dynamics also affect fuel consumption and emissions, leading to the specific rate of change between slope and fuel consumption not being consistent and a significant increase in the PN (Particulate Number) on some road sections. In addition, exhaust gas temperature may have a certain impact on emissions.

Exploring Outcomes of Tibial Rigid Intramedullary Nailing in Adolescent Patients.

To explore outcomes after tibial rigid intramedullary nailing (RIMN) in skeletally immature patients, with a focus on post-operative complications and iatrogenic changes in tibial slope due to anterior physeal arrest. Design: Retrospective case series. A large, tertiary care health system in the rural Mid-Atlantic United States, including two Level 1 trauma centers and one Level 2 trauma center. Included were skeletally immature patients within 2 years of skeletal maturity undergoing tibial RIMN for OTA/AO 42 A to C fractures between March 2009 and January 2024 with post-operative follow-up more than 1-year. The primary outcome was change in tibial slope after RIMN. Secondary outcomes included post-operative weight-bearing status and complications. Thirty-seven skeletally immature patients were included (mean age 15.2 ± 1.3 years, 76% male). For 22 patients with minimum 6-month post-operative radiographs (mean 18.4 ± 12.7 months), there was no significant change from pre- to post-operative tibial slope (80.0 ± 1.9° vs 80.1 ± 1.6°, p=0.86). Time to achievement of full weightbearing across the series averaged 45.4 ± 35.6 days. Five (14%) of patients necessitated hardware removal, and 89% of patients reported they had returned to "normal" activity at latest follow-up (mean 56.2 ± 42.5 months). This study demonstrated that RIMN for tibial shaft fractures in skeletally immature pediatric patients within 2 years of maturity was not associated with iatrogenic physeal injury and resultant changes in tibial slope. Additional favorable clinical outcomes, the potential for early weight-bearing, and few associated post-operative complications, indicate that RIMN is a safe option for skeletally immature patients with tibial shaft fractures. Caution should be exercised when extrapolating these results to younger pediatric patients with >2 years of skeletal growth remaining. IV.

Effect of a Financial Incentive Scheme for Medication Review on Polypharmacy in Elderly Inpatients With Dementia: A Retrospective Before-and-After Study.

Polypharmacy is an important healthcare issue, especially in elderly patients with dementia. As an incentive to reduce polypharmacy, a health insurance reimbursement scheme was introduced in 2016 for medication review and the reduction of medications for inpatients in Japan. However, the effects of these incentive schemes were not evaluated. We identified 1,465,881 inpatients aged ≥65 years with dementia. An interrupted time-series analysis was conducted by fitting a Prais-Winsten linear regression model. The outcome measure was the number of classes of medications prescribed during discharge. No significant changes were observed in the average number of medication classes at discharge immediately after the introduction of the scheme (coefficient: -0.022, 95% confidence interval [CI]: -0.17 to 0.13). The slope change, representing the effect of the intervention over time, was also not significant (coefficient: -0.00053, 95% confidence interval: -0.0012 to 0.00018). The incentive scheme was not associated with a reduction in the number of medication classes at discharge among older inpatients with dementia.

Changes in Dispensing of Acid Blockers to US Children: 2016–2023

OBJECTIVE To evaluate changes in the dispensing of acid blockers, defined as H2 receptor antagonists and proton pump inhibitors, to US children aged 0 to 18 years after ranitidine was recalled in late September 2019 and after the COVID-19 pandemic began. METHODS We analyzed the 2016–2023 IQVIA Longitudinal Prescription Database, which includes prescriptions dispensed from 92% of US retail pharmacies. Using an interrupted time series design, we assessed for level and slope changes in the monthly number of dispensed acid blocker prescriptions to children in October 2019 (month after ranitidine recall) and April 2020 (month after pandemic began). We repeated analyses among infants aged 0 to 1 year and older children aged 2 to 18 years. RESULTS In October 2019, there was a level decrease of 55 809 acid blocker prescriptions (95% CI, −92 038 to −19 580), representing a 11.0% decline relative to the predicted value in January 2016 (intercept). There was no level change in April 2020, but there was a slope increase (11 749 prescriptions/month, 95% CI, 595 to 22 903). Despite this increase, acid blocker dispensing in December 2023 was 10.9% lower than predicted had pre-October 2019 trends continued. Among infants and older children, dispensing was 25.5% and 4.7% lower than predicted, respectively. CONCLUSIONS Acid blocker dispensing to US children declined sharply after the ranitidine recall, illustrating the power of drug recalls to affect prescribing decisions in children. After the COVID-19 pandemic began, acid blocker dispensing recovered to a greater degree in older children compared to infants. Future research should investigate the reasons for these diverging trends.

Swash Zone Response to the Tsunami Triggered by the 2024 Noto Peninsula Earthquake

AbstractOn January 1, 2024, a destructive earthquake struck the Noto Peninsula in Japan, triggering a tsunami in the Sea of Japan. A 3D lidar, which was installed on a gravel beach 150 km from the epicenter before the earthquake, successfully measured nearshore waves and topographic changes during the tsunami event. This study is focused on the analysis of a novel data set to elucidate the swash zone processes caused by the tsunami, with a particular focus on the combined effects of the tsunami and wind waves on high wave runup and morphological changes. The observation data show that the mean sea level was elevated by 1 m when the largest tsunami arrived at the beach. In addition to the tsunami, wind waves reaching a height of 2 m induced wave setup of approximately 1 m and swash exceeding a height of 2 m. The empirical formulas considering the observed change in foreshore slope reasonably reproduced the observed runup heights, suggesting that an increase in the tsunami water level indirectly amplified wind wave runup by increasing the foreshore slope on the concave profile beach. High wind wave runup largely eroded the gravel beach, with the elevation of the upper beach face decreasing by 0.5 m during the tsunami event. We found that the area on the beach face affected by wind waves expanded in response to changes in the tsunami water level.

Observable and ionizing properties of star-forming galaxies with very massive stars and different initial mass functions

Context. The presence of very massive stars (VMS) with masses &gt; 100 M⊙ is now firmly established in the Local Group, nearby galaxies, and out to cosmological distances. If present, these stars could boost the UV luminosity and ionizing photon production of galaxies, helping to alleviate the overabundance of UV-bright galaxies found with JWST at high redshift. Aims. To examine these questions, we quantify the impact of VMS on properties of integrated stellar populations, exploring different stellar initial mass functions (IMFs) extending up to 400 M⊙, and with slopes between standard (Salpeter-like) and flatter, more top-heavy IMFs. Methods. Combing consistent stellar evolution and atmosphere models tailored to VMS at 1/2.5 Z⊙ metallicity with BPASS evolutionary synthesis models and including nebular emission, we computed integrated spectral energy distributions (SEDs) and derived quantities for a large set of models. Results. We find that VMS contribute significantly to the UV luminosity and Lyman continuum emission of young stellar populations, and they are characterized by strong stellar He II emission, with EW(He IIλ1640) up to 4–8 Å at young ages or ∼2.5 − 4 Å for a constant star formation rate (SFR) (for the IMFs considered here). For IMFs with a Salpeter slope, the boost of the UV luminosity is relatively modest (up to a factor of ∼1.6). However, small changes in the IMF slope (e.g., from α2 = −2.35 to −2) lead to large increases in LUV and the ionizing photon production, Q. The ionizing photon efficiency, ξion, is also increased with VMS, by typically 0.14–0.2 dex for a Salpeter slope, and by up to ∼0.4 dex when the IMF is extended up to 400 M⊙. Stronger H recombination lines are also predicted in the presence of VMS. Interestingly, SEDs including VMS show smaller Lyman breaks, and the shape of the ionizing spectra remain essentially unaltered up to ∼35 eV, but become softer at higher energies. We derive and discuss the maximum values that quantities such as LUV per stellar mass or unit SFR, ξion, Q, and others can reach when VMS are included, and we show that these values become essentially independent of the IMF. We propose observational methods to test for the presence of VMS and constrain the IMF in star-forming galaxies. Finally, using published JWST observations, we examine if high redshift (z ≳ 5 − 6) galaxies show some evidence of the presence of VMS and/or signs of non-standard IMFs. Very top-heavy IMFs can be excluded on average, but we find that the IMF could well extend into the regime of VMS and be flatter than Salpeter in the bulk of high-z galaxies. Conclusions. The predictions should improve our understanding of the stellar content and IMF of the most distant galaxies and allow us to establish if “extreme” or “unusual” populations extending well beyond 100 M⊙ existed in the early Universe.

Periodic and Aperiodic Components of Subthalamic Nucleus Activity Reflect Different Aspects of Motor Impairment in Parkinson's Disease.

Excessive beta oscillations in the subthalamic nucleus are established as a primary electrophysiological biomarker for motor impairment in Parkinson's disease and are currently used as feedback signals in adaptive deep brain stimulation systems. However, there is still a need for optimization of stimulation parameters and the identification of optimal biomarkers that can accommodate varying patient conditions, such as ON and OFF levodopa medication. The precise boundaries of 'pathological' oscillatory ranges, associated with different aspects of motor impairment, are still not fully clarified. In this study, we hypothesized that analysing periodic and aperiodic components of subthalamic nucleus activity separately and identifying functionally distinct subranges within 8-35 Hz based on oscillatory properties may reveal robust biomarkers for specific aspects of motor impairment. We analysed subthalamic nucleus activity of 14 patients with Parkinson's disease. Local field potentials were recorded at rest from externalized electrodes postoperatively, both before and after levodopa administration. We showed that levodopa administration suppressed oscillations across a broad frequency range (11-32 Hz) and increased the slope of the aperiodic component. Changes in the aperiodic slope correlated with motor symptom alleviation. Periodic activity was linked to motor symptom severity: Peak amplitude within the 14- to 20-Hz range correlated with overall motor impairment in the OFF state, whereas the 7- to 11-Hz range was associated with bradykinesia in the ON state. Our findings suggest that, in addition to low beta, alpha oscillations and the aperiodic component may serve as promising biomarkers for motor impairment and potential feedback signals in adaptive DBS systems.

Assessing microbial risks of Escherichia coli: A spatial and temporal study of virulence and resistance genes in surface water in resource-limited regions.

Environmental microbial pollution can potentially cause illnesses and deaths among human populations. Environmental factors such as geomorphology, land use, human activities, and seasonality could influence pathogen dissemination. This study performed a space-temporal analysis of Escherichia coli concentrations, virulence (eaeA, bfpA, stx2, aatA, and st), and resistance (tetA, blaTEM, blaOXA, Intl-1, Intl-2, sul-1, and sul-2) genes in surface water within the Virilla sub-watershed, Costa Rica. The research employs microbiological, geostatistical, and quantitative microbial risk assessment (QMRA) techniques to evaluate the health risks associated with diarrheagenic E. coli. Samples collected monthly over a year were analyzed for fecal coliforms, E. coli, Enterococcus faecalis, physicochemical parameters, and the presence of virulence and resistance genes. The geographically weighted regression model identified significant associations between the virulence and resistance genes presence and environmental factors influence such as land use, slope, altitude, and seasonal changes. The results show that urban and grazing land use significantly influence the presence of resistance genes, while human fecal pollution is associated with higher concentrations of virulence genes. Seasonal variations showed that wet seasons contributed to increased gene presence (number of positive samples) and diversity (variety of virulence and resistance genes) compared with dry season. The QMRA results indicated that the total health disease burden was higher than the benchmark for drinking water recommended by WHO (1.00×10-6 DALY - Disability-Adjusted Life Years - per person per year) by between one and four magnitudes orders, particularly in regions with urban and grazing land use, human fecal pollution class, and lower altitudes. This study highlights the relevance of integrating environmental and microbial data to enhance water quality management and public health strategies in resource-limited regions. It underscores the need for targeted interventions, such as improved wastewater treatment and establishing buffer zones, to mitigate the risks associated with microbial pollution in surface waters.

Evolution of Shoulder Type Escarpments Through Feedback Between Knickpoint and Windgap Migration

AbstractEscarpments and cliffs (hereafter termed escarpments) form topographic barriers that influence the spatial patterns of climate and biodiversity. The inherent extreme slope change across the escarpment edge promotes escarpment retreat over time. Typically, escarpments are divided into arch‐ and shoulder‐types. In arch‐type, the drainage divide is located inland, and knickpoints, located where channels flow across the escarpment, can retreat and embay the escarpment. In shoulder‐type, the divide aligns with the escarpment edge, a setting expected to cause a slow and uniform escarpment retreat, preserving their integrity as barriers through time. However, observations from around the globe reveal shoulder‐type escarpments are associated with deep embayments (i.e., alcoves) that destroy the linear appearance of the escarpment front. Yet, the processes that produce and sustain these embayments remain largely unexplored. Embayments of shoulder‐type escarpments typically occur along reversed channels which were part of the antecedent drainage that used to flow away from the escarpment but now flow toward it, often resulting in a valley confined drainage divide called a windgap. Here, we hypothesize that feedback between knickpoint retreat and windgap migration away from the escarpment along reversed channels can sustain escarpment embayments, and use topographic analyses and numerical simulations to explore this hypothesis. Our analyses, focused on field sites in the Negev Desert, show that embayments of shoulder‐type escarpments can be sustained through the hypothesized feedback, and quantify the sensitivity of this feedback to geomorphologic and lithologic parameters. Results suggest that this feedback may explain some of the global variability of escarpment morphologies.

Revisiting two thousand hinge fractures in open wedge high tibial osteotomy with a fifty years review: the oscillating saw cannot replace the traditional "ear-hand" dialogue between osteotome and hammer to estimate the elastic modulus of bone.

Hinge fracture on the lateral part of the tibia (LHF) is a common complication of medial Open Wedge High Tibial Osteotomy (OWHTO). Many factors have been described as risks for these fractures, but no study has compared an osteotome or an oscillating saw to prevent LHF following OWHTO. This "propensity-score-matched" (PSM) study was conducted from data obtained in the literature from 1974 to November 2024. A total of 10,368 knees with OWHTO were identified. After 1:1 matching based on correction amount, posterior slope change, surgeon's experience, the osteotome and oscillating groups comprised 2760 knees each. Among the 5520 knees of the PSM population, the prevalence of LHF was 6.1% in the osteotome alone group (168 cases), and 22% in the oscillating saw group (607 cases). The osteotome group had a significant lower prevalence of hinge fracture than the oscillating saw group (OR, 0.23; 95% CI, 0.19 to 0.27; p<0.0001) and a lower rate of clinically relevant hinge fractures with revision (OR, 0.34; 95% CI, 0.25 to 0.45; p<0.001. The osteotome may be an appropriate method for preventing hinge fractures following OWHTO.

Impact of magnetorheological fluid composition on their behaviour in gradient pinch mode

Magnetorheological (MR) fluids can be utilized in one of the fundamental operating modes of which the gradient pinch mode has been the least explored. In this unique mode non-uniform magnetic field distributions are taken advantage of to develop a so-called Venturi-like contraction in MR fluids. By adequately directing magnetic flux the material can be made solidified in the regions near the flow channel wall, thus creating a passage in the middle of the channel for the fluid to pass through. This leads to unique variations of the slope in the pressure-flow rate characteristics. It can be stated that the effect of the MR fluid composition on the behaviour of the MR fluid in gradient pinch mode has not been thoroughly investigated yet. In this study, the behaviour of MR fluids was assessed with a dedicated pinch mode MR valve that provided a valuable insight into the contraction mechanism using fluorescence microscopy. Briefly, seven MR fluid samples were prepared with different particle concentrations (10%, 22% and 32 vol%) and mean particle sizes (2, 4.5 and 8.2 μm). It was found that the MR fluid sample with the larger particle size exhibits a significantly larger slope change observed in the pressure-flow rate characteristics. Increasing the particle size from 2 μm (base) to 8 μm resulted in the slope increase by a factor of 2.6 compared to the base sample. Increasing the particle concentration has a negligible effect on the pinch mode effect. Finally, these results were analysed using the modified Wuest equation, which is commonly used for characterizing sharp-edged orifices in low Reynolds number flow regimes. The simple equation was determined to describe the behaviour of MR fluids in gradient pinch mode with adequate accuracy.