Miracle-dz/UniFAR-FTUs huggingface dataset:
The Theory of Matrices

Volume 2: XI. Complex symmetric, skew-symmetric, and orthogonal matrices: 1. Some formulas for complex orthogonal and unitary matrices 2. Polar decomposition of a complex matrix 3. The normal form of a complex symmetric matrix 4. The normal form of a complex skew-symmetric matrix 5. The normal form of a complex orthogonal matrix XII. Singular pencils of matrices: 1. Introduction 2. Regular pencils of matrices 3. Singular pencils. The reduction theorem 4. The canonical form of a singular pencil of matrices 5. The minimal indices of a pencil. Criterion for strong equivalence of pencils 6. Singular pencils of quadratic forms 7. Application to differential equations XIII. Matrices with non-negative elements: 1. General properties 2. Spectral properties of irreducible non-negative matrices 3. Reducible matrices 4. The normal form of a reducible matrix 5. Primitive and imprimitive matrices 6. Stochastic matrices 7. Limiting probabilities for a homogeneous Markov chain with a finite number of states 8. Totally non-negative matrices 9. Oscillatory matrices XIV. Applications of the theory of matrices to the investigation of systems of linear differential equations: 1. Systems of linear differential equations with variable coefficients. General concepts 2. Lyapunov transformations 3. Reducible systems 4. The canonical form of a reducible system. Erugin's theorem 5. The matricant 6. The multiplicative integral. The infinitesimal calculus of Volterra 7. Differential systems in a complex domain. General properties 8. The multiplicative integral in a complex domain 9. Isolated singular points 10. Regular singularities 11. Reducible analytic systems 12. Analytic functions of several matrices and their application to the investigation of differential systems. The papers of Lappo-Danilevskii XV. The problem of Routh-Hurwitz and related questions: 1. Introduction 2. Cauchy indices 3. Routh's algorithm 4. The singular case. Examples 5. Lyapunov's theorem 6. The theorem of Routh-Hurwitz 7. Orlando's formula 8. Singular cases in the Routh-Hurwitz theorem 9. The method of quadratic forms. Determination of the number of distinct real roots of a polynomial 10. Infinite Hankel matrices of finite rank 11. Determination of the index of an arbitrary rational fraction by the coefficients of numerator and denominator 12. Another proof of the Routh-Hurwitz theorem 13. Some supplements to the Routh-Hurwitz theorem. Stability criterion of Lienard and Chipart 14. Some properties of Hurwitz polynomials. Stieltjes' theorem. Representation of Hurwitz polynomials by continued fractions 15. Domain of stability. Markov parameters 16. Connection with the problem of moments 17. Theorems of Markov and Chebyshev 18. The generalized Routh-Hurwitz problem Bibliography Index.
Drag enhancement and drag reduction in viscoelastic fluid flow around a cylinder

We here use direct numerical simulations to describe the flow of a viscoelastic fluid, modeled using the so-called Oldroyd B model, around a cylinder in two dimensions. A wide range of flow parameters is covered in these simulations allowing to draw definitive conclusions as to the effect of viscoelasticity on such a flow situation. Both drag enhancement and drag reduction are observed and a phase diagram is proposed in the parameter space Reynolds number vs. Weissenberg number. While only drag enhancement is observed below a Reynolds number of 40, both drag enhancement and drag reduction are observed for higher Reynolds numbers indicating that drag reduction is a feature associated with the shedding of vortices behind the cylinder. An interesting observation accompanies the onset of drag enhancement in the vortex-shedding regime: the shedding is suppressed.
Intensive Systolic Blood Pressure Treatment Remodels Brain Perivascular Spaces: A Secondary Analysis of SPRINT

BackgroundBrain perivascular spaces (PVS) are part of the glymphatic system and facilitate clearance of metabolic byproducts. Since enlarged PVS are associated with vascular health, we tested whether intensive systolic blood pressure (SBP) treatment affects PVS structure.MethodsThis is a secondary analysis of the Systolic PRessure INTervention (SPRINT) Trial MRI Substudy: a randomized trial of intensive SBP treatment to goal < 120 mm Hg vs. < 140 mm Hg. Participants had increased cardiovascular risk, pre-treatment SBP 130-180, and no clinical stroke, dementia, or diabetes. Brain MRIs acquired at baseline and follow-up were used to automatically segment PVS in the supratentorial white matter and basal ganglia using a Frangi filtering method. PVS volumes were quantified as a fraction of the total tissue volume. The effects of SBP treatment group and major antihypertensive classes on PVS volume fraction were separately tested using linear mixed-effects models while covarying for MRI site, age, sex, black race, baseline SBP, history of cardiovascular disease (CVD), chronic kidney disease, and white matter hyperintensities (WMH). ResultsFor 610 participants with sufficient quality MRI at baseline (mean age 678, 40% female, 32% black), greater PVS volume fraction was associated with older age, male sex, non-Black race, concurrent CVD, WMH, and brain atrophy. For 381 participants with MRI at baseline and at follow-up (median = 3.9 years), intensive treatment was associated with decreased PVS volume fraction relative to standard treatment (interaction coefficient: -0.029 [-0.055 to -0.0029] p=0.029). Reduced PVS volume fraction was also associated with exposure to calcium channel blockers (CCB) and diuretics.ConclusionsIntensive SBP lowering partially reverses PVS enlargement. The effects of CCB use suggests that improved vascular compliance may be partly responsible. Improved vascular health may facilitate glymphatic clearance.
Clinical outcome and outcome prediction of octogenarians with acute basilar artery occlusion and endovascular stroke treatment compared to younger patients

Purpose: Elderly patients, especially octogenarians, are underrepresented in recently published studies, that showed a benefit of endovascular stroke treatment (EST) for patients with acute basilar artery occlusion (BAO). We aimed to compare the clinical outcome of octogenarians with BAO and EST compared to younger patients and to identify independent outcome predictors. Methods: This is a retrospective, single-center analysis of patients treated for BAO with EST from 01/2013 until 06/2021 in a tertiary stroke center. Octogenarians were compared to younger patients. Study endpoint was the clinical outcome as per mRS 90 days after stroke onset. The study groups were compared in univariate analysis and a multivariate logistic regression analysis was performed to define independent predictors for clinical outcome. Results: In this study, 74/191 (38.7%) octogenarians had a higher pre-stroke mRS (median, IQR 2, 1 - 3 vs. 0, 0 - 1 in younger patients, p < 0.001) and a comparable NIHSS before EST (median, IQR 21, 8 - 34 vs. 22, 10 - 38 in younger, p = 0.712). They showed a comparable mRS 90d after stroke onset (median, IQR 5, 3-6 vs. 5, 2-6 in younger), p = 0.194), but less often a good clinical outcome (mRS 0-2: n = 27, 23% younger vs. n = 9, 11.7% octogenarians, p = 0.004). The rate of bad clinical outcome was comparable (mRS 5-6, n = 63, 46.7% younger vs. 39, 50.6% octogenarians, p = 0.194). Baseline NIHSS was a stable independent predictor for clinical outcome in both study groups (e.g. for bad clinical outcome: in octogenarians OR 1.04 CI 100 - 10.85, p = 0.0019, in younger OR 1.061, CI 1.027 - 1.098, p = 0.005) Conclusion: Octogenarians with acute BAO eligible for EST are less likely to be functionally independent at 90 days after stroke onset, but the rate of death or severe handicap is comparable to younger patients. The admission NIHSS predicts clinical outcome in both age groups.
Evidence of Leaky Protection Following COVID-19 Vaccination and SARS-CoV-2 Infection in a US Correctional Facility Population

Whether SARS-CoV-2 infection and COVID-19 vaccines confer exposure-dependent ("leaky") protection remains unknown. We examined the effect of prior infection and vaccination on infection risk among residents of Connecticut correctional facilities during periods of predominant Omicron and Delta transmission. Residents with cell, unit, and no documented exposures to SARS-CoV-2 infected residents were matched by facility and date. During the Omicron period, prior infection and vaccination reduced the infection risk of residents without a documented exposure (Hazards ratio: infection, 0.36 [0.25-0.54]; vaccination, 0.57 [0.42-0.78]) and with cellblock exposures (infection, 0.61 [0.49-0.75]; vaccination, 0.69 [0.58-0.83]) but not with cell exposures (infection, 0.89 [0.58-1.35]; vaccination, 0.96 [0.64-1.46]). Associations were similar during the Delta period and when analyses were restricted to residents who underwent testing. These findings suggest that SARS-CoV-2 infection and COVID-19 vaccination may be leaky, highlighting the potential benefits of pairing vaccination with non-pharmaceutical interventions in densely crowded settings.
TIME-OF-FLIGHT MASS SPECTROMETER WITH IMPROVED RESOLUTION

A new type of ion gun is described which greatly improves the resolution of a nonmagnetic time‐of‐flight mass spectrometer. The focusing action of this gun is discussed and analyzed mathematically. The validity of the analysis and the practicability of the gun are demonstrated by the spectra obtained. The spectrometer is capable of measuring the relative abundance of adjacent masses well beyond 100 amu.
Effect of continuous anesthetic wound infusion on postoperative activity in patients who underwent midline laparotomy for gynecological diseases

Objective This study aimed to assess whether continuous anesthetic wound infusion (CAWI) increases postoperative activity in patients who undergo midline laparotomy for gynecological diseases. Methods This was an unplanned secondary analysis of a randomized controlled trial examining the effect of an activity tracker with feedback on postoperative activity in patients who underwent midline laparotomy for gynecological diseases (NCT02025387). Of the 53 patients included in the trial (12 patients used CAWI and 41 patients did not), 11 patients with CAWI (case group) and 11 without CAWI (control group) were selected by matching the duration of surgery. We compared the postoperative activity and other endpoints between the case and control groups. Results The case and control groups had similar baseline and surgical characteristics. The recovery rate on postoperative day 4 (step counts at day 4/ daily step counts at preoperative baseline) of the case group was numerically higher, but not significantly different from that of the control group (58% vs. 44%; p=0.450). Least, average and present pain on postoperative day 2 were lower in the case group than in the control group. Pain on postoperative day 5, fatigue, gas out, soft blend diet initiation, ileus, and length of hospital stay were similar between the case and control groups. Conclusions In this exploratory analysis, CAWI was not associated with increased postoperative activity in patients who underwent midline laparotomy for gynecological diseases.
Community and health system factors influencing snake envenomation management practices in three districts of Ghana: a qualitative inquiry from health stakeholders and snakebite victims

Introduction Snakebite is a neglected public health issue affecting individuals of all ages in many tropical countries. Venom from snakebite is a potentially life-threatening disease associated with severe morbidities and mortalities. However, literature on snakebite envenoms management practices remains understudied. This study sought to explore community and health system factors influencing snake envenomation management practices in three districts in the Oti region of Ghana. Also, we assessed the current adherence to snakebite treatment protocols to the national and World Health Organization (WHO) recommended protocols. Methods The study adopted an exploratory descriptive qualitative study design. Purposive sampling technique was used to recruit participants for the study. The participants included snakebite victims, traditional healers, and health professionals. In-depth interviews and focused group discussions were used to collect data from the participants. All the interviews were audio recorded and transcribed verbatim and exported to Atlas Ti for data management and analyses. The transcribed data were analyzed using the content analysis method to develop the categories for the study findings Findings Twenty-six (26) participants were recruited including 16 males and 10 females. The study found three main factors that influenced snake envenomation management practices. These factors included health system factors, community-level factors, and adherence to national and WHOrecommended protocols. The health system factors included the unavailability of anti-snake venom, high-cost ASV, and inadequate or no supply of ASV from Ghana Health Service. The community factors included delay in seeking treatment, transportation, and accessibility challenges, and non-community acceptance facility treatment of snakebites. Almost all the health care professional who provide care for snakebite victims adhered to the WHO recommendations. Conclusion The evidence adduced from this study could be used by public health practitioners to empower the community by increasing awareness of the prevention of snakebites, first aid, and appropriate treatment-seeking behavior. Culturally appropriate interventions that seek to increase awareness to improve the acceptability of hospital management and sensitize the community for early referral of snakebite victims to the nearest health facility having anti-venom treatment. Authors summary The negative responses by the communitys acceptance of the kind of treatment given in the health facilities and the unavailability of Anti-snake Venom (ASV) in the study districts' health facilities inhibit the management of snakebites.
Saliva microbiome alterations in dental fluorosis population

ABSTRACT Background We aimed to explore saliva microbiome alterations in dental fluorosis population. Methods The prevalence of dental fluorosis was examined in 957 college students. Dean’s fluorosis index was used to evaluate the dental fluorosis status. Changes in the composition of the salivary microbiome were assessed in a subset of these patients (100 healthy controls, 100 dental fluorosis patients). Results Dental fluorosis affected 47% of the student sample, and incidence was unrelated to gender. Compared with healthy controls, the microbiota of patients with dental fluorosis exhibited increased diversity, with increased abundance of Treponema lecithinolyticum, Vibrio metschnikovii, Cupriavidus pauculus, Pseudomonas, Pseudomonadaceae, Pseudomonadales, and decreased abundance of Streptococcus mutans, Streptococcus sanguinis, Gemella, and Staphylococcales. Function analyses showed increases in arginine biosynthesis in patients affected by dental fluorosis, together with reductions in amino sugar and nucleotide sugar metabolism, fructose and mannose metabolism, and starch and sucrose metabolism. Conclusions These results suggest that there are striking differences in salivary microbiome between healthy controls and dental fluorosis patients. Dental fluorosis may contribute to periodontitis and systemic lung diseases. There is a need for cohort studies to determine whether altering the salivary microbiota in dental fluorosis patients can alter the development of oral or systemic diseases.
Peripheral brain-derived neurotrophic factor (BDNF) and salivary cortisol levels in college students with different levels of academic stress. Study protocol

Introduction Brain-derived neurotrophic factor (BDNF) is essential for brain physiological processes influencing memory and learning. BDNF levels can be affected by many factors, including stress. Stress increase serum and salivary cortisol levels. Academic stress is of the chronic type. BDNF levels can be measure from serum, plasma or platelets, and there is still no standard methodology, which is relevant to ensure reproducibility and comparability between studies. Hypothesis (i) BDNF concentrations in serum show greater variability than in plasma. (ii) In college students with academic stress, peripheral BDNF decreases and salivary cortisol increases. General objective To standardize plasma and serum collection for BDNF levels and to determine whether academic stress affects peripheral BDNF and salivary cortisol levels. Design Quantitative research, with a non-experimental cross-sectional descriptive design. Participants Student volunteers. Under convenience sampling, 20 individuals will be included for standardization of plasma and serum collection and between 70 and 80 individuals to determine the effect of academic stress on BDNF and salivary cortisol. Peripheral blood and salivary cortisol sampling, measurements 12 mL of peripheral blood (with and without anticoagulant) will be drawn per participant, separated from plasma or serum and cryopreserved at -80°C. Additionally, they will be instructed in the collection of 1 mL of saliva samples, which will be centrifuged. Val66Met polymorphism will be performed by allele-specific PCR, while BDNF and salivary cortisol levels will be determined by ELISA. Statistical analysis (i) descriptive analysis of the variables, through measures of central tendency and dispersion, and the categorical variables through their frequency and percentage. (ii) Then a bivariate analysis will be performed comparing groups using each variable separately. Expected results We expect to (i) determine the analytical factors that allow a better reproducibility in the measurement of peripheral BDNF, and (ii) the effect of academic stress on BDNF and salivary cortisol levels.
Serum leucine-rich α2 glycoprotein as a potential biomarker for systemic inflammation in Parkinson’s disease

There is ample epidemiological and animal-model evidence suggesting that intestinal inflammation is associated with the development of Parkinson’s disease (PD). Leucine-rich α2 glycoprotein (LRG) is a serum inflammatory biomarker used to monitor the activity of autoimmune diseases, including inflammatory bowel diseases. In this study, we aimed to investigate whether serum LRG could be used a biomarker of systemic inflammation in PD and to help distinguish disease states. Serum LRG and C-reactive protein (CRP) levels were measured in 66 patients with PD and 31 age-matched controls. We found that serum LRG levels were statistically significantly higher in the PD group than in the control group (PD: 13.9 ± 4.2 ng/mL, control: 12.1 ± 2.7 ng/mL, p = 0.036). LRG levels were also correlated with Charlson comorbidity index (CCI) and CRP levels. LRG levels in the PD group were correlated with Hoehn and Yahr stages (Spearman’s r = 0.40, p = 0.008). LRG levels were statistically significantly elevated in PD patients with dementia as compared to those without dementia (p = 0.0078). Multivariate analysis revealed a statistically significant correlation between PD and serum LRG levels after adjusting for serum CRP levels, and CCI (p = 0.019). We conclude that serum LRG levels could be considered a potential biomarker for systemic inflammation in PD.
When are clients helpful? Capitalising on client involvement in professional service delivery

Professional service firms apply specialist knowledge to create customised solutions to client problems. In their work, teams of professionals undertake projects in which clients may be closely involved in co-creating solutions. However, we know little about the conditions under which client involvement contributes to better performance. We examine the direct and conditional contribution client involvement can make to project success and propose team bonding capital as a moderator. We conduct multi-level analysis of data from 58 project managers and 171 consultants nested in project teams. We find a positive impact of client involvement on both team performance and team member idea creativity. Team bonding capital moderates the relationships client involvement has with both team performance and individual member idea creativity, where the impact of client involvement is greater when team bonding capital is high. Implications for theory and practice are discussed.
Changes in frontal plane kinematics over 12-months in individuals with the Percutaneous Osseointegrated Prosthesis (POP)

Background A bone-anchored prosthesis (BAP) eliminates the need for a conventional socket by attaching a prosthesis directly to the user’s skeleton. Currently, limited research addresses changes in gait mechanics post BAP implantation. Objective Examine changes in frontal plane movement patterns after BAP implantation. Methods Participants were individuals with unilateral transfemoral amputation (TFA) enrolled in the US Food and Drug Administration (FDA) Early Feasibility Study examining the Percutaneous Osseointegrated Prosthesis (POP). The participants completed overground gait assessments using their conventional socket and at 6-weeks, 12-weeks, 6-months, and 12-months following POP implantation. Statistical parameter mapping techniques were used in examining changes in frontal plane kinematics over the 12-months and differences with reference values for individuals without limb loss. Results Statistically significant deviations were found pre-implantation compared to reference values for hip and trunk angles during prosthetic limb stance phase, and for pelvis and trunk relative to the pelvis angles during prosthetic limb swing. At 6-weeks post-implantation, only the trunk angle demonstrated a statistically significant reduction in the percent of gait cycle with deviations relative to reference values. At 12-months post-implantation, results revealed frontal plane movements were no longer statistically different across the gait cycle for the trunk angle compared to reference values, and less of the gait cycle was statistically different compared to reference values for all other frontal plane patterns analyzed. No statistically significant within-participant differences were found for frontal plane movement patterns between pre-implantation and 6-weeks or 12-months post-implantation. Conclusions Deviations from reference values displayed prior to device implantation were reduced or eliminated 12-months post-implantation in all frontal plane patterns analyzed, while within-participant changes over the 12-month period did not reach statistical significance. Overall, the results suggest the transition to a BAP aided in normalizing gait patterns in a sample of relatively high functioning individuals with TFA.