Variation In Leakage Research Articles

OCT Macular Volume as a Predictor of Vascular Leakage in Uveitis.

IntroductionThis study aimed to evaluate the optical coherence tomography (OCT) macular volume as a marker for active vascular leakage in patients with intermediate and pan uveitis.MethodsIn this single-center prospective longitudinal study, patients were included under three criteria: diagnosed with noninfectious intermediate or pan uveitis; presented vascular leakage at their initial visit; and were imaged with concurrent wide-field fluorescein angiography (FA) and OCT. A scoring system was employed to measure vascular leakage. OCT volume scans were performed on the patients to produce the corresponding thickness map. The central subfield thickness (CST) and macular volume (MV) were calculated. CST is defined as the average thickness within the 1-mm fovea circle, while MV includes the 3-mm and 6-mm circles on the thickness map. Mixed-effects models were applied to analyze the correlation between each patient’s OCT and FA imaging results.ResultsA total of 72 patients (115 eyes) were included. The median follow-up time was 11 months (interquartile range 1.8–16.1 months). A total of 679 observations across all time points were analyzed. Both CST and MV were found to be positively associated with the leakage scores (p < 0.001). In the mixed-effects models, MV in the 6-mm circle presented the strongest correlation with leakage scores, which explained 57% of the variation in leakage (p < 0.001). MV in the 3-mm circle and CST explained 45.8% and 39.5%, respectively.ConclusionCST and MV in both the 6-mm and the 3-mm circles demonstrated significant correlations with angiographic inflammatory activity. Among those imaging parameters, MV in the 6-mm circle has the highest correlation. The study results suggest that this parameter can be considered a quantitative and non-invasive alternative to FA for monitoring vasculitic inflammation in uveitis.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40123-022-00558-z.

Nitrogen rich PECVD silicon nitride for passivation of Si and AlGaN/GaN HEMT devices

In this work, we have investigated the material properties of PECVD (Plasma Enhanced Chemical Vapor Deposition) amorphous Silicon nitride (SiN) films and the influence of deposition conditions on gate-leakage increase of AlGaN/GaN HEMT’s (High Electron Mobility Transistor) after passivation. We have studied the effect of gas flow ratio (SiH4/NH3) on the structural and compositional properties of SiNx deposited on crystalline Silicon (Si). Based on the inference, electrical properties of the SiNx films were examined by depositing on AlGaN/GaN HEMT as a passivation layer. The optimized SiNx which is N-rich with a refractive index of 1.83, tensile stress of 681 MPa and NH3/SiH4 ratio of 18 shows only a 1.2x variation in gate leakage, 1.4x increase in gm, minimum left shift of 0.03 V in Vth and 1.26x increase Ion/Ioff ratio after passivation. We believe that the 3x reduction in Si-H bonds resulting in reduced interface traps at SiN/AlGaN interface is the reason for the minimal increase in gate leakage after passivation.

COVID-19: mask efficacy is dependent on both fabric and fit.

Aim: Face masks are an important addition to our arsenal in the fight against COVID-19. The aim of this study is to present a novel method of measuring mask performance which can simultaneously assess both fabric penetration and leakage due to poor fit. Materials & methods: A synthetic aerosol is introduced into the lung of a medical dummy. A conical laser sheet surrounds the face of the dummy where it illuminates the aerosol emitted during a simulated breath. The system is demonstrated with five mask types. Conclusions: The curved laser sheet highlights both penetration through the mask fabric and leakage around the edges of the mask. A large variation in both material penetration and leakage was observed.

Information leakage of ADRs Prior to company issued guidance

We examine whether the degree of selective disclosure (as measured by information leakage prior to managerial earnings guidance) of foreign firms with ADRs is different from that of U.S. firms. We find that there is no variation of leakage before earning guidance between ADRs and U.S. firms. This result is consistent with the prediction that, despite being exempt from Regulation FD, ADRs have sufficient incentives to avoid selective disclosure even without the regulatory enforcement. In addition, we attempt to determine whether the variation in selective disclosure among the foreign firms with ADRs is conditioned on the respective home country transparency and governance standards. We find that country-specific characteristics, such as corruption perception, economic freedom and the legal system origin, explain the variation in information leakage of ADRs.

Vertical Current Transport in AlGaN/GaN HEMTs on Silicon: Experimental Investigation and Analytical Model

We investigate the vertical leakage mechanism in metal–organic chemical vapor deposition-grown carbon (C)-doped AlGaN/GaN High Electron Mobility Transistors (HEMTs) on 6-in silicon wafer. Substrate bias polarity-dependent ${I}$ – ${V}_{s}$ , temperature-dependent fitting, and band diagram analysis pointed to the Poole–Frenkel (P–F) type of conduction mechanism for vertical transport in the devices with breakdown as high as 580 V for a buffer of $\textsf {4}~\mu \text{m}$ . Trap activation energy of 0.61 eV was estimated from the P–F fitting which matches well with values reported in the literature. We propose that higher dislocation density leads to shallower traps in the buffer and build an analytical model of dislocation-mediated vertical leakage around this. The variation in leakage as a function of dislocation density at a given field is predicted and is found to be the most abrupt in the range from $\sim 10^{\textsf {7}}$ to $\sim 10^{\textsf {9}}$ cm $^{-\textsf {2}}$ of dislocation density. This can be attributed to a sharp decrease in trap activation energy in the above range of dislocation density, possibly due to complex formation between point defects and dislocations.

A Study on the Policies Concerning the Management of Employment Leak Age in Three Star Hotels in the Greater Cairo Region

Employee leakage is achieving basic levels for some Hotels chain, which battle to keep up legitimate staffing levels in a tight labour market (WeiBo et al. 2010). Leakage has been a measure of performance in hotels that is costs lots of money related to financial and operational effectiveness. Organizational stability is known to have a high level of relationship with low leakage. Signs are that employees will probably stay when there is an anticipated and stable workplace (Zuber, 2001). The current study conducted through cross-sectional design to gather primary data in order to determine causes for the high employee leakage in three-star hotels. Data were collected from the professional, supervisory, and managerial staff in these hotels in greater Cairo. Using regression analysis, it was determined that the individual leakage causes and satisfaction was a statistically significant variable when analyzing leakage causes in the current study. Over 25% of the variation in leakage causes was explained by the components of the survey. This research is important to industry professionals as well as academics to help estimate and decrease staffs’ leakage in various sectors of the hospitality industry. Based on the results obtained, the study showed a set of recommendations such as implementing a career development plan and acknowledging the talents and abilities gained by the hotel workers. Human resource management should offer support to employees and a stable and healthy work environment. One-on-one conferences should be scheduled between workers and their managers. Key words : leakage, retention, three-star hotels.

Surface water leakage, sedimentation and evaporation in arid regions: A case study of the Gargar dam, Algeria

AbstractThis study was carried out in order to assess the total capacity loss in Gargar dam, third-largest in Algeria, due to the mudding of the reservoir, intense evaporation and water leaks. We analysed the variation in leakage as a function of the reservoir level, and quantify losses due to leaks, sedimentation and evaporation. We relied on site visits and data obtained from the Algerian Agency for Dams and Transfers to assess the leakage volume; reservoir level; sedimentation and evaporation levels for the period 1988–2015. We present an updated report of this problem through the dam. We estimated total average losses of 23 million m3·year−1 for the period 1988–2015, made up of leakage (0.3 million m3·year−1), evaporation (18 million m3·year−1) and dead storage for 4.6 million m3·year−1. However, total losses for 2004 were estimated at 113.9 million m3, which increased to the alarming value of 166.8 million m3 in 2015. We suggest improving the waterproofness by a concrete screen, and reducing mudding and evaporation by reforestation, to increase the storage capacity of the dam.

The surface water storage problem in arid regions: a case study of the Gargar Dam, Algeria

Most dams lose capacity as a result of three principal phenomena: leakage, sedimentation and evaporation. The study of these phenomena is particularly important as they can also endanger the dam’s stability. Here, we examine the case of the Gargar dam in western Algeria. This dam is located in an arid zone where water resources are becoming increasingly scarce. It is situated 5 km from the city of Ghelizane and is subject to considerable water loss. It has never been filled to capacity, and is now threatened by leakages that are clearly evolving over time. This article extends our earlier studies of the dam. Our work has estimated total average losses of 25 million m 3 /year for the period 1988–2015, made up of leakage (0.3 million m 3 /year) and evaporation (18 million m 3 /year), while dead storage accounts for 4.6 million m 3 /year. However, total losses for 2004 were estimated at 113.9 million m 3 , which increased to the alarming value of 166.8 million m 3 in 2015. We analyze variation in leakage as a function of the reservoir level, and quantify losses due to leaks, sedimentation and evaporation. Keywords: Gargar Dam; Leakage; Sedimentation; Evaporation; Arid areas; Algeria

Hospital Variation in Anastomotic Leakage After Rectal Cancer Surgery in the Spanish Association of Surgeons Project: The Contribution of Hospital Volume

ObjectiveThis multicentre observational study aimed to determine the anastomotic leak rate in the hospitals included in the Rectal Cancer Project of the Spanish Society of Surgeons and examine whether hospital volume may contribute to any variation between hospitals. MethodsHospital variation was quantified using a multilevel approach on prospective data derived from the multicentre database of all adenocarcinomas of the rectum operated by an anterior resection at 84 surgical departments from 2006 to 2013. The following variables were included in the analysis; demographics, American Society of Anaesthesiologists classification, use of defunctioning stoma, tumour location and stage, administration of neoadjuvant treatment, and annual volume of elective surgical procedures. ResultsA total of 7231 consecutive patients were included. The rate of anastomotic leak was 10.0%. Stratified by annual surgical volume hospitals varied from 9.9% to 11.3%. In multilevel regression analysis, the risk of anastomotic leak increased in male patients, in patients with tumours located below 12cm from the anal verge, and advanced tumour stages. However, a defunctioning stoma seemed to prevent this complication. Hospital surgical volume was not associated with anastomotic leak (OR: 0.852, [0.487–1.518]; P=.577). Furthermore, there was a statistically significant variation in anastomotic leak between all departments (MOR: 1.475; [1.321–1.681]; P<.001). ConclusionAnastomotic leak varies significantly among hospitals included in the project and this difference cannot be attributed to the annual surgical volume.

ポータブル機器における半導体リーク電流特性のばらつきを考慮したシステムモデルの生産システムへの応用

ポータブル機器における半導体リーク電流特性のばらつきを考慮したシステムモデルの生産システムへの応用

Impact of Regulatory Enforcement on Leakages Prior to Analyst Recommendations

AbstractThe financial press suggests that information is commonly leaked prior to analyst recommendations. We examine the impact that three regulatory actions (Regulation Fair Disclosure, Global Analysts Research Settlement, and the legal case against Galleon Group) have on information leakage prior to analyst recommendations. We find that all three regulatory actions have significantly reduced the leakage of information prior to analyst recommendations, even after controlling for several characteristics that explain the variation in information leakage. Our results are robust when applying an alternative method of measuring information leakage, and when forming various samples of analyst recommendations based on different criteria.

Reproducibility of a cough and jump stress test for the evaluation of urinary incontinence

The study seeks to determine whether a urinary cough and jump stress test is reproducible and whether there is a relationship between a stress test and a 24-h pad test and our subjective Stress Incontinence Index. Multicenter prospective cohort study of women with subjective stress incontinence. Each patient completed a validated Stress and Urge Incontinence Questionnaire and a 24-h pad test and performed two standardized cough and jump stress tests. All 108 women were incontinent during both the first and second stress tests. There was a large variation in leakage and the leakage was significantly larger during stress test 2 than during stress test 1 (P < 0.02). Correlations found between the stress test and the 24 hour pad test and between the stress test and the Stress Incontinence Index were poor. The cough and jump stress test is reproducible and able to document stress leakage.

Variation in Transistor Performance and Leakage in Nanometer-Scale Technologies

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Variation in transistor characteristics is increasing as CMOS transistors are scaled to nanometer feature sizes. This increase in transistor variability poses a serious challenge to the cost-effective utilization of scaled technologies. Meeting this challenge requires comprehensive and efficient approaches for variability characterization, minimization, and mitigation. This paper describes an efficient infrastructure for characterizing the various types of variation in transistor characteristics. A sample of results obtained from applying this infrastructure to a number of technologies at the 90-, 65-, and 45-nm nodes is presented. This paper then illustrates the impact of the observed variability on SRAM, analog and digital circuit blocks used in system-on-chip designs. Different approaches for minimizing transistor variation and mitigating its impact on product performance and yield are also described. </para>

MLC dosimetric characteristics for small field and IMRT applications

The objective of this work was to measure the performance characteristics of a double-focus multileaf collimator (MLC) for intensity modulated radiation therapy (IMRT), specifically the variation in penumbra and leakage for narrow fields as a function of field position over a 20x27 cm space available for segmented MLC IMRT. Measurements were made with 6 MV x rays through a MLC containing 29 leaf pairs (27 pairs of 1 cm width), and EDR2 film at 10 cm depth in solid water at 100 cm SAD. Films were digitized with 0.17 mm resolution and converted to dose. Interleaf and intraleaf transmission were measured along 11 vertical profile locations. Leaf-end transmission was measured along horizontal profiles for each of 9 different leaf abutments, traveling over a 20 cm range. In-plane penumbra measurements were made through a single leaf retracted, for 7 different leaves. Cross-plane penumbra (leaf-end) measurements were made for all 27 leaf pairs, where the 1 cm field width was placed in 11 different off-axis positions (20 cm range). Interleaf leakage (range 1.0%-1.5%), intraleaf transmission (range 0.6%-0.8%), and leaf-end transmission (range 0.8%-2.7%) were consistent for all leaf pairs at a given abutment position. The penumbra for these 1-cm-wide fields was measured to be 0.36 cm+/-0.03 cm for 99% of the measurements. In conclusion, the penumbra and leakage of the double-focus MLC were remarkably consistent for the range of leaf positions studied, producing dosimetric characteristics that are well suited for IMRT segments where opposing leaf pairs are often separated by 10 mm or less.

Light Leakage Effects with Different Sample Holder Geometries in Quantitative Near-Infrared Transmission Spectroscopy of Pharmaceutical Tablets

Transmission geometry is becoming an alternative to the conventional reflectance geometry in near-infrared (NIR) spectroscopy of pharmaceuticals. An advantage of transmission NIR is that it samples a volume whereas reflectance NIR merely samples the surface region of solid preparations. This leads to more representative measurements on complex matrices, such as some types of tablets. However, more attention must be paid to sample presentation with respect to light leakage. An investigation of the effects of the light leakage obtained with different sample holder geometries on content calibrations for transmission NIR on tablets was performed. Two different model samples, a composite and a compact tablet, were measured in sample wells in which the diameters and heights were varied according to a multivariate design. This was done in order to simulate a mismatch between the tablet and the sample well. Partial least-squares (PLS) models were built and used to evaluate the significance of the sample well geometry. Liquid chromatography was used as a reference method. As expected, for both types of tablets it was found that a small mismatch in tablet-to-well diameter deteriorated the repeatability of the NIR spectra, although, unexpectedly, this gave the best predictions and more robust models. In all, this indicates that light leakage should not be minimized at calibration, but included as a factor in the multivariate model that spans the future expected variation in light leakage.

Imaging of Ca2+ transients in endothelial cells of single perfused capillaries: correlation of peak [Ca2+]i with sites of macromolecule leakage.

To investigate the mechanisms responsible for variation in the macromolecular leakage (formation of localized leaky sites) in venular microvessels with increased permeability, we examined the hypothesis that cytoplasmic calcium concentration [Ca2+]i, does not increase uniformly within microvessel endothelial cells. We loaded the endothelial cells forming the walls of venular microvessels in frog mesentery with fura-2, and imaged [Ca2+]i using a cooled CCD camera. Control [Ca2+]i was close to 60 nM in all regions. Control permeability was uniformly low in all microvessels. Exposure to ionomycin (5 mM) increased [Ca2+]i in a biphasic manner, but not uniformly. There was variation in both time to peak (bimodal distribution) and peak [Ca2+]i (274 +/- 13 nM; mean variation above or below the peak value was 110 nM). Raising extracellular calcium from 1.1 to 5 mM increased the mean variation of [Ca2+]i about peak values. Extravascular leakage of fluorescently labeled albumin or low-density lipoproteins was most prominent at sites where increase in [Ca2+]i were largest. These data indicate that variation in [Ca2+]i within individual endothelial cells or groups of cells could account, at least in part, for the distribution of localized leakage sites for macromolecules in venular microvessels in the high-permeability state.

Genotypic Variation in Chilling-induced Leakage of Electrolytes from Leaf Tissue of Tomato ( Lycopersicon esculentum Mill.) in Relation to Growth under Low-energy Conditions

Summary Differences between 10 genotypes of tomato ( Lycopersicon esculentum Mill.) with respect to electrolyte leakage from leaf tissue after a chilling treatment (EL) were demonstrated. Effects of growing temperature and light intensity on EL were also observed. The inheritance of EL was studied. The variation in this membrane character was controlled by additive gene action. Comparison between EL data and literature data on the growth of the different genotypes indicated an effect of membrane characters related to EL in plant performance.

Variation in Germination and Amino Acid Leakage of Seeds with Temperature Related to Membrane Phase Change

Leakages of amino acids and/or fluorescent material as functions of temperature between 15 and 40 C are reported for imbibed seeds of Avena fatua L., Lactuca sativa L., Barbarea vulgaris R. Br., Amaranthus albus L., Abutilon theophrasti Medic., Lychnis alba Mill., Daucus carota L., Setaria faberi Herrm., Setaria viridis (L.) Beauv., and Datura stramonium L. The leakage indicates prominent increase in permeability of the plasmalemma in the 30 to 35 C range for 8 of the 10 kinds of seeds studied. Germination of the seeds at constant temperatures or with daily shifts in temperature is related to the membrane transition temperature for permeation by amino acids. Seeds of A. albus and A. theophrasti, which did not show membrane changes in the 25 to 40 C range, germinated best at 35 to 40 C; the other seeds germinated best below 30 C. Seeds of B. vulgaris showed rapid permeation of limiting membranes upon initial wetting with water, which was indicative of membrane disorder when dry. Leakage under anaerobiosis was observed for S. faberi seeds.

Investigations into rhizosphere microflora

Effect of light and dark treatments on rhizosphere and rhizoplane microflora of two crops,viz Triticum aestivum. Linn. andHordeum vulgare Linn. has been investigated. Higher microbial population was recorded from the rhizosphere of plants exposed to continuous light while continuous dark set harboured lesser microflora. The microflora in 12 hours alternate light and dark set exhibited an intermediate condition. Amino acids (both qualitatively and quantitatively) in root extracts were the least in continuous dark and the maximum in continuous light set. The variation in root leakage, physiological and morphological condition of the plants was thought to be the cause for change in microbial activity.