Bias Control Research Articles

Modeling and Analysis of DC Magnetic Bias Effect for 1000kV Ultra-High Voltage Transformer

DC magnetic bias refers to a series of complicated electrical, magnetic, force, sound, heat and other abnormal phenomena caused by DC current intrusion into the transformer winding, which causes half-cycle saturation of core flux, which will seriously endanger the safe and stable operation of the transformer. Since the 1000kV UHV substation is very important in the power system, and the UHV transformer has lower DC current tolerance than the general transformer, it is necessary to accurately evaluate the DC bias risk of the UHV transformer during the design phase. This paper provides a reference for the DC bias magnetization prevention and control of UHV transformers by modelling and analysing the DC bias magnetization of 1000 kV UHV substation in Changsha. .

Effects of contamination and climate in the Pediatric Emergency Department visits for acute respiratory infection in the City of Buenos Aires.

Pollution and climate have an impact on pediatric respiratory diseases; few studies have assessed this in the Autonomous City of Buenos Aires. To assess the impact of the interaction between air pollutants and climate on the Emergency Department visits for acute lower respiratory tract infection (ALRTI) in a children's hospital. Ecological, time-series study with generalized additive models that included total visits and visits for ALRTI to the Emergency Department between 2012 and 2016. A series with 7-day moving averages for ALRTI visits was founded as a bias control measure. Predictors were daily levels of air pollutants (carbon monoxide, nitrous dioxide, particulate matter < 10 μ) and meteorological variables (temperature, humidity). Pollutants were measured at three monitoring stations. Temporal variables (day of the week, warm/cold semester) were controlled. There were 455 256 total visits; 17 298 accounted for visits for ALRTI. A correlation was established only between total visits and day of the week (Mondays and Saturdays, more visits; Thursdays, less visits). Less visits for ALRTI were recorded in the warm semester compared to the cold semester (relative risk = 0.23; 95 % confidence interval: 0.29-0.18; p < 0.001). One monitoring station did not show any correlation; the other two stations showed a weak correlation between carbon monoxide and particulate matter < 10 μ and visits for ALRTI. The season accurately accounts for the increased number of total visits and visits for ALRTI. Although there was a correlation between the level of certain pollutants and the number of visits, its impact was irrelevant.

Does the CEO elite education affect firm hedging policies?

This paper studies the relationship between CEO elite education and firm hedging decisions. It uses the particular specificities of the French post-secondary educational institutions to examine the effect of CEO educational background on the use of foreign currency derivatives. The results show a positive and significant relationship between education quality and derivatives use. Neither the level nor the type of education has any significant effect. The results also show that the use of derivatives enhances firm performance only when CEOs are from elite institutions. These results are robust to a battery of tests that involve alternative estimation techniques, the use of different subsamples, additional control variables, and control for endogeneity and selection bias.

The Nature of Evaluation Part I: Relation to Psychology.

The discipline of evaluation is devoted to the systematic determination of merit, worth, or significance. It is divided into fields according to the type of entity evaluated—for example, program evaluation, or personnel evaluation—and there are more than twenty of these recognized fields of evaluation. Some specific aspects of evaluation methodology have been developed to solve problems of evaluation in only one or a few of these fields (e.g., bias control in panel selection, systematic side-effect identification in program evaluation, road-testing techniques in product evaluation). However, the underlying logic of the process of evaluation—for example, the difference between merit and worth, or between grading and ranking—and a substantial portion of its general methodology (e.g., techniques of measurement, causality determination, applying the requirement of informed consent) are shared across all or many of these fields. Many of these general techniques (the ‘general methodology’) come from the applied social sciences, and are learnt by students in the normal course of education in those fields. But the logic of evaluation has been developed for and applies only to evaluation; and the field-specific methodologies of evaluation must also be mastered in order to deal with evaluation in the fields to which they apply. Teaching evaluation therefore focuses on these evaluation-specific topics, the general logic and the special methodologies.

A 10-mA LDO With 16-nA IQ and Operating From 800-mV Supply

A low-dropout (LDO) regulator with a quiescent current in the tens of nanoampere range and operating from 800-mV supply is proposed. A rail-to-rail buffer with zero input–output (I/O) voltage shift and based on the differential flipped voltage follower is used for combined gate and bulk driving of the output device. Therefore, bulk modulation with forward body bias is implemented without any additional amplifier. The proposed buffer is a crucial block for the sub-1-V supply and for limiting the contribution of the output device to the quiescent current. The error amplifier (EA) is adaptively biased with a bias shaper block, which implements a current limiting at high loads and a linear dependence on the output current at moderate loads. The feedback signal for the bias control is the output of the amplifier instead of the gate voltage of the pass device, thus combining a nanoampere bias at light load with the ability to follow a fast output current transient. Finally, a corner-tracking load is used to set the bias current of the output device to the minimum value at the target stability margin over the temperature and process parameters’ space. The LDO was implemented in a 55-nm CMOS technology. The measured quiescent current is 16 nA with a minimum power supply rejection of 42.7 dB up to 50 kHz and a maximum load current of 10 mA. In order to compare the transient behavior of the state-of-the-art designs, a modified figure of merit is proposed, taking into account the penalty caused by the low supply.

Bias Controller of Mach-Zehnder Modulator for Electro-Optic Analog-to-Digital Converter.

As one of the core devices for an electro-optic analog-to-digital converter (ADC), the Mach–Zehnder (MZ) modulator plays an important role, and the output stability of the MZ modulator has a decisive influence on the conversion accuracy of the ADC. This paper proposed a pilot tone-based method to stabilize the bias point of the modulator. This method could obtain the corresponding control voltage of the MZ modulator by adding a KHz-level dither tone to the bias end of the modulator and calculating the ratio of the first and second harmonic components. The experimental results showed that the output optical power of the modulator was stable at 3.2 dB when the bias point of the modulator was set at the orthogonal point. Moreover, the fluctuation range was not more than 0.15 dB, the first harmonic of the output signal was stable at 50.5 dB, and the fluctuation range was not more than 0.6 dB. The proposed bias controller based on the field programmable gate array (FPGA) and digital signal processing (DSP) can stabilize the modulator bias point at the orthogonal point and with a relatively high locking accuracy.

Moffitt Cancer Center 2-Year Single-Institution Experience with Next-Generation Sequencing Minimal Residual Disease Detection: Clinical Utility, Application, and Correlation with Outcomes in Plasma Cell and Lymphoid Malignancies

Moffitt Cancer Center 2-Year Single-Institution Experience with Next-Generation Sequencing Minimal Residual Disease Detection: Clinical Utility, Application, and Correlation with Outcomes in Plasma Cell and Lymphoid Malignancies

TOTAL AND POST-DISCHARGE 30-DAY EPISODE PAYMENTS FOR BENEFICIARIES WITH ALZHEIMER’S AND DEMENTIA

There exists lack of evidence regarding incremental post-discharge cost and utilization of healthcare services for older adults with Alzheimer’s and dementia (AD). We quantified episode payments associated with AD vs. non-AD 30 days after medical or surgical procedures. We utilized administrative claims between January 2012 and June 2017 from the Michigan Value Collaborative (MVC) across 31 different medical and surgical services. We identified all patients with any AD diagnosis code throughout their enrollment using ICD-9-CM, ICD-10-CM codes. We price standardized 30-day episode payments and split them based on patient setting. Payments were risk adjusted and winsorized at the 99th /1st percentile. Propensity score matching using calipers without replacement adjusted for clinically relevant surgical and medical procedures, HCCs, insurance type, and age to control for selection bias. We identified 66,676 AD episodes and 656,235 non-AD episodes. After propensity score matching, there were 58,485 AD and non-AD episodes with significant differences in total episode payments of ($22,378 vs. $19,595, 95% CI Diff: ($2,658, $2,910)). Post-acute care and readmission payments were significant ($4,561 vs. $3,272, 95% CI Diff: ($1,235, $1,342)) and ($1,807 vs. $1,165, 95% CI Diff: ($595, $691)), respectively. AD episodes had a higher readmission rate (21.6% vs. 14.8%, p<0.0001). County variation in payments for AD episodes was substantial (Median: $4,370, Range: $3,881). AD patients are at higher risk of readmission and more resource intensive to hospitals and health systems. Examining drivers of post-discharge cost variation can influence practice pattern changes in management of AD patients.

Outpatient Versus Inpatient Surgical Fixation of Isolated Ankle Fractures: An Analysis of 90-Day Complications, Readmissions, and Costs

Despite increasing interest toward managing isolated ankle fractures in an outpatient setting, evidence of its safety remains largely limited. The 2007 to 2014 Humana Administrative Claims database was queried to identify patients undergoing open reduction internal fixation for unimalleolar, bimalleolar, or trimalleolar isolated closed ankle fractures. Two cohorts (outpatient versus inpatient) were then matched on the basis of age, sex, race, region, fracture type (uni-/bi-/trimalleolar) and Elixhauser Comorbidity Index to control for selection bias. Multivariate regression analyses were performed to report independent impact of outpatient-treated ankle fracture surgery on 90-day complications, readmission, and emergency department visit rates. Independent-samples t test was used to compare global 90-day costs between cohorts. A total of 5317 inpatient-treated and 6941 outpatient-treated closed ankle fractures were included in the final cohort. After matching and multivariate analyses, patients with outpatient ankle fractures, compared with patients with inpatient ankle fractures, had statistically lower rates of pneumonia (2.3% versus 4.0%; p < .001), myocardial infarction (0.9% versus 1.8%; p = .005), acute renal failure (2.2% versus 5.3%; p < .001), urinary tract infections (7.4% versus 12.3%; p < .001), and pressure ulcers (0.9% versus 2.0%; p = .001). Outpatient ankle fractures also had lower rates of 90-day readmissions (9.7% versus 14.1%; p < .001) and emergency department visits (13.8% versus 16.2%; p = .028). Last, overall 90-day costs for outpatient ankle fractures were nearly $9000 lower than costs for inpatient ankle fractures ($12,923 versus $21,866; p < .001). Based on our findings, it appears that outpatient treatment of ankle fractures can be deemed safe and feasible in a select cohort of patients.

Profiling Green Consumers

Many studies have tried using demographics and other measures to improve our understanding of prospective green buyers and to learn how to encourage more green behaviors. This study employed two online surveys of U.S. adults (total of 1,330 respondents) to examine the contribution of demographic, psychographic, and other variables for describing consumers with environment-friendly attitudes. The results confirmed the limited value of demographics (e.g., age was not related to green attitudes). New variables tested included impulsiveness behavior, privacy concerns, religiosity, spirituality, risk and time preferences, handedness, and political orientation. Although most green studies have not included social desirability bias controls, this measure appeared to be important. Other variables that were positively linked to green attitudes include hedonic consumption, privacy concerns, spirituality measures, risk preferences, and liberal political preferences. These results offer new insights for building segments of green consumers, for developing messages for these consumers, and for efficiently communicating with consumers who have environment-friendly attitudes.

Neglog: Homology-Based Negative Data Sampling Method for Genome-Scale Reconstruction of Human Protein-Protein Interaction Networks.

Rapid reconstruction of genome-scale protein–protein interaction (PPI) networks is instrumental in understanding the cellular processes and disease pathogenesis and drug reactions. However, lack of experimentally verified negative data (i.e., pairs of proteins that do not interact) is still a major issue that needs to be properly addressed in computational modeling. In this study, we take advantage of the very limited experimentally verified negative data from Negatome to infer more negative data for computational modeling. We assume that the paralogs or orthologs of two non-interacting proteins also do not interact with high probability. We coin an assumption as “Neglog” this assumption is to some extent supported by paralogous/orthologous structure conservation. To reduce the risk of bias toward the negative data from Negatome, we combine Neglog with less biased random sampling according to a certain ratio to construct training data. L2-regularized logistic regression is used as the base classifier to counteract noise and train on a large dataset. Computational results show that the proposed Neglog method outperforms pure random sampling method with sound biological interpretability. In addition, we find that independent test on negative data is indispensable for bias control, which is usually neglected by existing studies. Lastly, we use the Neglog method to validate the PPIs in STRING, which are supported by gene ontology (GO) enrichment analyses.

Intraoperative Surgical Navigation Reduces the Surgical Time Required to Treat Acute Major Facial Fractures.

Assessing bone reduction and implant placement in facial fractures is time-consuming because of limited visibility. An intraoperative navigation system allows real-time confirmation of bone positioning and implant placement on the patient's computed tomographic scan. This circumvents the visibility problem and therefore appears to shorten the surgery time. The goal of this study was therefore to determine whether intraoperative navigation reduces the surgical time required to treat patients with acute major facial fractures. In this retrospective quasi-experimental study, 50 patients with major facial fractures were identified and randomly assigned to treatment groups. Twenty-two were treated without the use of a navigation system, and 28 were treated using navigation. The Facial frActure Severity Score (FASS) was devised to better assess and control for complexity of cases and control for possible selection bias. The FASS was directly linked to surgery time, whether or not navigation was used. An analysis of covariance demonstrated that the surgical time required to treat major facial fractures, taking into account the FASS, was reduced by 36.1 percent (124.8 minutes) when navigation was used. This study compared the surgical time required to treat patients with major facial fractures, with and without a navigation system. The use of a navigation system reduced the surgical time by 36.1 percent. This is a significant improvement in reducing the length of craniomaxillofacial procedures. Therapeutic, III.

YI02.03 Statistical Pitfalls in Clinical Trial Design

YI02.03 Statistical Pitfalls in Clinical Trial Design

THE BENCHMARK OF INVESTOR DECISIONS TO INVEST IN THE INITIAL PUBLIC OFFERING (IPO)

This study aims to examine how the influence of benchmarks used by investors in the process of making investment decisions during the IPO. The dependent variable in this study is the investment decision while the independent variable is financial behavior bias consisting of reputation underwriter, CEO reputation, financial statements, representativeness bias, availability bias, overconfidence bias and self control bias. In research using primary data by providing questionnaires to investors who invest during the IPO. The population is investors in Yogyakarta with a sample of 100 respondents taken by purposive sampling method according to the specified criteria. Questionnaires were tested with validity and reliability tests. To test the hypothesis multiple regression analysis is used. The results of this study indicate that reputation underwriters, CEO reputation, financial statements, representativeness bias and availability bias do not affect investment decision making during the IPO process. While overconfidence bias and self control bias have a significant positive effect on investment decision making during the IPO process.

Bi-Level Model Predictive Control for Optimal Coordination of Multi-Area Automatic Generation Control Units under Wind Power Integration

With the high degree of wind power penetration integrated into multi-area AC/DC interconnected power grids, the frequency regulation capacity of automatic generation control (AGC) units is not sufficient in the wind power-penetrated area, making it difficult to effectively suppress the frequency stability caused by the fluctuation of wind power. Therefore, a coordinated control strategy for AGC units across areas based on bi-level model predictive control is proposed in this paper to achieve resource sharing. The control scheme uses economic model predictive control to realize steady power optimal allocation of the AGC units across areas in the upper layer and distributed model predictive control to realize dynamic frequency optimization control of the multi-area AGC units in the lower layer. Taking a three-area AC/DC interconnected power grid with a wind farm as an example, the simulation results show that, compared with model predictive control using tie-line frequency bias control (TBC) mode, the proposed control strategy can not only effectively maintain tie-line safety and frequency stability, but can also reduce the regulation cost of multi-area AGC units.

Signaling the trustworthiness of science

Trust in science increases when scientists and the outlets certifying their work honor science’s norms. Scientists often fail to signal to other scientists and, perhaps more importantly, the public that these norms are being upheld. They could do so as they generate, certify, and react to each other’s findings: for example, by promoting the use and value of evidence, transparent reporting, self-correction, replication, a culture of critique, and controls for bias. A number of approaches for authors and journals would lead to more effective signals of trustworthiness at the article level. These include article badging, checklists, a more extensive withdrawal ontology, identity verification, better forward linking, and greater transparency.

Optimal automatic generation controllers in a multi‐area interconnected power system with utility‐scale PV plants

The centralised utility-scale photovoltaic (PV) plants installation has greatly enlarged their percentage in the bulk power systems, along with the nature uncertainty for the balance of system power and loads. Consequently, the successful integration of solar PV power in large-scale power systems requires a reliable and efficient multi-area automatic generation control (AGC) system within the control centre. Specifically, area-AGCs that perform tie-line bias control, in which the area frequency regulates the tie-line power flow, must balance the operational control area supply power-and-demand loads within a pre-tuned parameter set. Traditional AGC control systems have area linear controllers that must be periodically tuned to manage the high fluctuation of PV power. A practical two-step tuning method to determine the optimal parameters of existing multi-area AGCs is presented. The proposed method is demonstrated on a five-area multi-machine power system with two large PV plants. The power system was equipped with the synchrophasor-based monitoring system, with a real-time simulation platform serving as the application host. Results indicated that the two-step tuning method provides optimal parameters for all the system AGCs over a wide range of PV penetration levels. Typical results demonstrated the effectiveness of the tuned multi-area AGCs under dynamic conditions and disturbances.

P: 9 Pharmacotherapies that Specifically Target Ammonia for the Prevention and Treatment of Hepatic Encephalopathy in Adults With Crrhosis

BACKGROUND: Ammonia plays a key role in the genesis of hepatic encephalopathy (HE). Recent interest has focused on drugs which specifically target ammonia, e.g. sodium benzoate (SB), glycerol phenylbutyrate (GPB), ornithine phenylacetate (OP), AST-120, and polyethylene glycol (PEG). This study aims to evaluate the utility of these pharmacotherapies vs. placebo or non-absorbable disaccharides (NAD), for the management of HE in people with cirrhosis. L-ornithine L-aspartate is not included. METHODS: Electronic/manual searches of the literature were undertaken for relevant RCTs. The results of the meta-analyses are presented as risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CIs). Bias control was assessed using the CHBG domains and the certainty of the evidence using GRADE. RESULTS: Eleven RCTs were identified involving SB (n = 1), GPB (n = 1), OA (n = 2), AST-120 (n = 2) and PEG (n = 3). Treatment periods ranged from five days to 16 weeks. All but one trial was at “high risk of bias”; the certainty of the evidence was very low for all outcomes. Nine trials, with 733 participants, reported blood ammonia concentrations. Significant reductions were observed in placebo-controlled trials evaluating SB (MD −32.00, 95% CI −46.85 to −17.15); GPB (MD −12.00, 95% CI −23.37 to −0.63); OP (MD −27.10, 95% CI −48.55 to −5.65) and AST-120 (MD −22.00, 95% CI −26.75 to −17.25). No significant differences in blood ammonia concentrations were observed when compared to NADs. Eleven trials, with 943 participants, reported mortality data, although there were no events in five trials. No beneficial or harmful effects were found in any of the trials. Seven trials, with 521 participants reported data on HE. Beneficial effects were identified for GPB vs. placebo (RR 0.57, 95% CI 0.36 to 0.90; 178 participants; 1 trial; NNTB = 6) and for PEG vs. lactulose (RR 0.19, 95% CI 0.08 to 0.44; 190 participants; 3 trials; NNTB = 4); no beneficial effects were observed in the remaining three trials with extractable data (Figure 1). Ten trials, with 790 participants, reported a total of 130 serious adverse events. There was no evidence of beneficial or harmful effects of the five agents when compared to placebo or NADs. CONCLUSIONS: These agents generally reduce blood ammonia concentrations, when compared to placebo, but not when compared to NADs. Their overall effects on clinical outcomes of interest and the potential harms associated with their use remain uncertain. Further evidence is needed to fully evaluate their utility in this clinical setting.

P: 51 Aminoglycosides and Metronidazole for the Prevention and Treatment of Hepatic Encephalopathy in Adults With Cirrhosis

BACKGROUND: The EASL/AASLD guidelines stipulate that both neomycin and metronidazole may be used as alternatives for the treatment of overt HE, whereas the Italian guidelines state that these antibiotics are currently not recommended, mainly because of their potential systemic toxicity. This study aims to evaluate the utility of aminoglycosides and metronidazole vs. placebo, non-absorbable disaccharides (NAD) and other active treatment, for the management of HE in adults with cirrhosis. METHODS: Electronic/manual searches of the literature were undertaken for relevant RCTs. The results of the meta-analyses are presented as risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CIs). Bias control was assessed using the CHBG domains and the certainty of the evidence using GRADE. RESULTS: Twenty RCTs evaluated aminoglycosides including neomycin (n = 15) paromomycin (n = 4), and ribostamycin (n = 1). Treatment periods ranged from 3 to 168 days. Comparators included: placebo (n = 2), NADs (n = 7), other antibiotics viz. rifaximin, erythromycin and ciproxin (n = 9) and BCAAs (n = 2). All but one trial was at 'high risk of bias'; the certainty of the evidence was low or very low for all outcomes. Twenty trials, with 1110 participants, reported mortality data, although there were no events in 12 trials. No differential beneficial or harmful effects were found in any of the trials (RR 1.10, 95% CI 0.89 to 1.42, I2 6%, P = 0.39). Seventeen trials, with 1025 participants reported data on HE. No differential beneficial or harmful effects were found in any of the trials (RR 0.89, 95% CI 0.57 to 1.39, I2 69%, P = 0.62). Twenty trials, with 1110 participants, reported 778 serious adverse events (SAEs), although there were no events in eight trials. Use of the aminoglycosides was associated with more SAEs including pneumonia and renal failure (RR 1.46, 95% CI 0.99 to 2.16, I2 0%, P = 0.06) (Figure 1). One RCT evaluated metronidazole vs. rifaximin. Treatment was administered for three days as an adjunct to oral lactulose, LOLA and thrice daily enemata. Both regimens were equally as effective; no adverse events were reported. CONCLUSIONS: Although no significant differences were observed between the effects of aminoglycosides and other interventions, in relation to death and HE, in patients with cirrhosis, their use may be associated with an increased risk of serous adverse events. The utility of metronidazole for the management of HE can not be evaluated on the basis of the available literature. Neither drug should be used routinely in this setting.

Comprehensive genomic profiling of glioblastoma tumors, BTICs, and xenografts reveals stability and adaptation to growth environments

Glioblastoma multiforme (GBM) is the most deadly brain tumor, and currently lacks effective treatment options. Brain tumor-initiating cells (BTICs) and orthotopic xenografts are widely used in investigating GBM biology and new therapies for this aggressive disease. However, the genomic characteristics and molecular resemblance of these models to GBM tumors remain undetermined. We used massively parallel sequencing technology to decode the genomes and transcriptomes of BTICs and xenografts and their matched tumors in order to delineate the potential impacts of the distinct growth environments. Using data generated from whole-genome sequencing of 201 samples and RNA sequencing of 118 samples, we show that BTICs and xenografts resemble their parental tumor at the genomic level but differ at the mRNA expression and epigenomic levels, likely due to the different growth environment for each sample type. These findings suggest that a comprehensive genomic understanding of in vitro and in vivo GBM model systems is crucial for interpreting data from drug screens, and can help control for biases introduced by cell-culture conditions and the microenvironment in mouse models. We also found that lack of MGMT expression in pretreated GBM is linked to hypermutation, which in turn contributes to increased genomic heterogeneity and requires new strategies for GBM treatment.