Based on earlier studies that have shown Saturn's middle magnetosphere to contain turbulent magnetic field fluctuations, we analyze the spatial and temporal variations of the magnetic fluctuations ...and turbulent heating rate as a function of local time and magnetic phase. The region of study is Saturn's plasma sheet at a distance of 6–20 Rs, where Rs is Saturn's equatorial radius. The data set consists of magnetic field data measured during 92 orbits (revolutions) from the equatorial phases of Cassini covering 9 years from 2004 to 2012. We find asymmetries in the magnetosphere with enhanced fluctuations around noon. With respect to longitude we find increased fluctuations at 65° southern and 250° northern magnetic phase. This leads to an increased turbulent heating rate in these regions and is consistent with regions of increased plasma density and maximum downward field‐aligned currents according to the quasi‐dipolar perturbation fields. Analysis of single orbits reveals that the heating rate of 79% of all analyzed inbound and outbound legs is significantly (statistical error less than 1%) sinusoidally modulated. The modulation of the turbulent heating rate is predominantly observed during times when Cassini is located between dusk and midnight and additionally at dawn.
Key Points
Magnetic fluctuations and turbulence in Saturn's plasma sheet are modulated by the magnetic phase
Turbulent heating peaks at 65°/250° for southern/northern magnetic phase, respectively
Peak turbulence coincides with maximum downward field‐aligned currents and enhanced plasma density
ABSTRACT We present results from a numerical forward model to evaluate one-dimensional reduced power spectral densities (PSDs) from arbitrary energy distributions in -space. In this model, we can ...separately calculate the diagonal elements of the spectral tensor for incompressible axisymmetric turbulence with vanishing helicity. Given a critically balanced turbulent cascade with and , we explore the implications on the reduced PSD as a function of frequency. The spectra are obtained under the assumption of Taylor's hypothesis. We further investigate the functional dependence of the spectral index κ on the field-to-flow angle θ between plasma flow and background magnetic field from MHD to electron kinetic scales. We show that critically balanced turbulence asymptotically develops toward θ-independent spectra with a slope corresponding to the perpendicular cascade. This occurs at a transition frequency , which is analytically estimated and depends on outer scale L, critical balance exponent , and field-to-flow angle θ. We discuss anisotropic damping terms acting on the -space distribution of energy and their effects on the PSD. Further, we show that the spectral anisotropies as found by Horbury et al. and Chen et al. in the solar wind are in accordance with a damped critically balanced cascade of kinetic Alfvén waves. We also model power spectra obtained by Papen et al. in Saturn's plasma sheet and find that the change of spectral indices inside can be explained by damping on electron scales.
Modern electrophysiological recordings simultaneously capture single-unit spiking activities of hundreds of neurons spread across large cortical distances. Yet, this parallel activity is often ...confined to relatively low-dimensional manifolds. This implies strong coordination also among neurons that are most likely not even connected. Here, we combine in vivo recordings with network models and theory to characterize the nature of mesoscopic coordination patterns in macaque motor cortex and to expose their origin: We find that heterogeneity in local connectivity supports network states with complex long-range cooperation between neurons that arises from multi-synaptic, short-range connections. Our theory explains the experimentally observed spatial organization of covariances in resting state recordings as well as the behaviorally related modulation of covariance patterns during a reach-to-grasp task. The ubiquity of heterogeneity in local cortical circuits suggests that the brain uses the described mechanism to flexibly adapt neuronal coordination to momentary demands.
Patients with chronic lung disease (CLD) have an increased risk for severe coronavirus disease-19 (COVID-19) and poor outcomes. Here, we analyze the transcriptomes of 611,398 single cells isolated ...from healthy and CLD lungs to identify molecular characteristics of lung cells that may account for worse COVID-19 outcomes in patients with chronic lung diseases. We observe a similar cellular distribution and relative expression of SARS-CoV-2 entry factors in control and CLD lungs. CLD AT2 cells express higher levels of genes linked directly to the efficiency of viral replication and the innate immune response. Additionally, we identify basal differences in inflammatory gene expression programs that highlight how CLD alters the inflammatory microenvironment encountered upon viral exposure to the peripheral lung. Our study indicates that CLD is accompanied by changes in cell-type-specific gene expression programs that prime the lung epithelium for and influence the innate and adaptive immune responses to SARS-CoV-2 infection.
Background
Diverting ileostomy is utilized to protect high‐risk anastomoses, though it is not shown to reduce the leak rate it may reduce the severe consequences of an anastamotic leak. In recent ...years mesh development has advanced to allow placement of meshes into potentially contaminated fields, such as an ostomy closure site.
Method
A retrospective review of all ileostomy closure procedures in Gold Coast from 1st January 2011 until 31st December 2018 were included. Patient demographics and surgical outcomes and follow up reviewed to identify any cases of incisional hernia relating to ostomy closure.
Results
A total of 193 patients were identified, after exclusions 171 were suitable for analysis within the study, a total of 25 incisional hernia detected radiologically or clinically. Two independent risk factors were identified BMI >30 and ASA 3–4. Both had significant association with development of incisional hernia with a 3‐ and 2‐fold RR increase, respectively. This was also reflected in a subset analysis of BMI ranges demonstrating increased risk in the obese and severely obese group.
Discussion
The high‐risk group in our population was elevated BMI and ASA, these are the patients we would expect to benefit the most from targeted therapy to reduce the incidence of incisional hernia. Future studies to look at whether reducing BMI or prophylactic mesh placement are effective.
Transfer entropy (TE) provides a generalized and model-free framework to study Wiener-Granger causality between brain regions. Because of its nonparametric character, TE can infer directed ...information flow also from nonlinear systems. Despite its increasing number of applications in neuroscience, not much is known regarding the influence of common electrophysiological preprocessing on its estimation. We test the influence of filtering and downsampling on a recently proposed nearest neighborhood based TE estimator. Different filter settings and downsampling factors were tested in a simulation framework using a model with a linear coupling function and two nonlinear models with sigmoid and logistic coupling functions. For nonlinear coupling and progressively lower low-pass filter cut-off frequencies up to 72% false negative direct connections and up to 26% false positive connections were identified. In contrast, for the linear model, a monotonic increase was only observed for missed indirect connections (up to 86%). High-pass filtering (1 Hz, 2 Hz) had no impact on TE estimation. After low-pass filtering interaction delays were significantly underestimated. Downsampling the data by a factor greater than the assumed interaction delay erased most of the transmitted information and thus led to a very high percentage (67-100%) of false negative direct connections. Low-pass filtering increases the number of missed connections depending on the filters cut-off frequency. Downsampling should only be done if the sampling factor is smaller than the smallest assumed interaction delay of the analyzed network.
Despite advances in symptomatic treatment options the pathomechanism of idiopathic Parkinson’s disease (PD) remains poorly understood. Animal studies from recent years suggest pathological ...information processing in the basal ganglia network to be responsible for major movement deficits observed in patients, which, according to the information lesion hypothesis, might also explain the mechanism of action of deep brain stimulation (DBS). Using novel measures from information theory we characterize the information content, storage and transfer of intraoperatively recorded local field potentials (LFP) from the subthalamic area of n = 19 PD patients undergoing surgery for implantation of electrodes for deep brain stimulation. In agreement with recent animal studies we demonstrate a significant positive correlation of subthalamic information content and movement deficits (ρ > 0.48). Analysis of information storage reveals a larger processing memory in the zona incerta (ZI) than in the subthalamic nucleus (STN). We discuss possible implications for the efficiency of high frequency DBS. Further, we estimate the information transfer between forearm muscles and ZI/STN. Here, we show that the bidirectional information flow with respect to the STN is larger compared to the ZI. In contrast to the STN, however, the bidirectional information flow in the ZI is modulated, namely increased, by movement. The results of our study may help to understand the mechanism of action of deep brain stimulation and further explain recent studies claiming efficiency of ZI stimulation for certain motor symptoms.
Background
Anastomotic leaks (AL) remain a devastating complication following intestinal anastomoses resulting in increased morbidity and mortality. Wrapping the anastomosis with omentum may be ...protective although data are conflicting. We performed a meta‐analysis to assess the effect of omentoplasty on colorectal anastomoses.
Methods
PubMed, EMBASE and Cochrane databases were searched for relevant articles from inception until August 2021. All randomized controlled trials (RCT) that reported on the use of omentoplasty in colon and rectal surgery were included. The primary outcome was rate of overall AL while secondary outcomes included clinical and radiological AL, overall reoperation and mortality. Random effects models were used to calculate pooled effect size estimates. Sensitivity analyses were also performed.
Results
Four RCTs were included capturing 1067 patients. The mean (SD) age of the cohort was 61.5 (±14.8) years. On random effects analysis, omentoplasty reduced rate of overall (OR 0.43, 95% CI = 0.21–0.87, p = 0.02) and clinical AL (OR = 0.35, 95% CI = 0.15–0.81, p = 0.01). However, there was no difference in radiological AL (OR = 0.77, 95% CI = 0.40–1.47, p = 0.42), overall reoperations (OR 0.48, 95% CI = 0.18–1.32, p = 0.16) or mortality (OR 0.52, 95% CI = 0.12 to–2.18, p = 0.37). On sensitivity analysis, assessing rectal anastomoses only, the results for overall AL remained similar (OR 0.28, 95% CI = 0.12–0.61, p = 0.002).
Conclusion
Although omentoplasty appears to reduce the rate of overall and clinical AL, the heterogeneity in the data prevents definitive recommendations from being made. Further well‐designed trials are needed to investigate this technique.
Covering a colorectal anastomosis with omentum may be beneficial although it is not standard practice due to conflicting data. The current study summarizes all the available evidence on omentoplasty in colorectal surgery and demonstrates that it reduces overall and clinical leak rates. Further studies are needed to confirm these findings.
Abstract
Background
A large evidence-practice gap exists regarding provision of nutrition to patients following surgery. The aim of this study was to evaluate the processes supporting the ...implementation of an intervention designed to improve the timing and adequacy of nutrition following bowel surgery.
Methods
A mixed-method pilot study, using an integrated knowledge translation (iKT) approach, was undertaken at a tertiary teaching hospital in Australia. A tailored, multifaceted intervention including ten strategies targeted at staff or patients were co-developed with knowledge users at the hospital and implemented in practice. Process evaluation outcomes included reach, intervention delivery and staffs’ responses to the intervention. Quantitative data, including patient demographics and surgical characteristics, intervention reach, and intervention delivery were collected via chart review and direct observation. Qualitative data (responses to the intervention) were sequentially collected from staff during one-on-one, semi-structured interviews. Quantitative data were summarized using median (IQR), mean (SD) or frequency(%), while qualitative data were analysed using content analysis.
Results
The intervention reached 34 patients. Eighty-four percent of nursing staff received an awareness and education session, while 0% of medical staff received a formal orientation or awareness and education session, despite the original intention to deliver these sessions. Several strategies targeted at patients had high fidelity, including delivery of nutrition education (92%); and prescription of oral nutrition supplements (100%) and free fluids immediately post-surgery (79%). Prescription of a high energy high protein diet on postoperative day one (0%) and oral nutrition supplements on postoperative day zero (62%); and delivery of preoperative nutrition handout (74%) and meal ordering education (50%) were not as well implemented. Interview data indicated that staff regard nutrition-related messages as important, however, their acceptance, awareness and perceptions of the intervention were mixed.
Conclusions
Approximately half the patient-related strategies were implemented well, which is likely attributed to the medical and nursing staff involved in intervention design championing these strategies. However, some strategies had low delivery, which was likely due to the varied awareness and acceptance of the intervention among staff on the ward. These findings suggest the importance of having buy-in from all staff when using an iKT approach to design and implement interventions.
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