Variable Resistance Research Articles

A new method for current–voltage curve prediction in photovoltaic modules

In this work, a new method for obtaining the current–voltage curve for crystalline silicon and thin-film flat panels is presented. It is based on the single-diode model, with a variable shunt resistance and series resistance. New expressions for the shunt resistance and open circuit voltage as a function of the temperature and irradiance are deduced. Besides, a procedure to translate the series resistance to arbitrary conditions is proposed. The diode ideality factor and shunt resistance are obtained by optimization. The rest of the parameters that appear in the current–voltage curve are obtained from the module measurements by means of theoretical expressions. The procedure for obtaining the current–voltage curve under arbitrary operating conditions is also described. The results obtained with the developed model are compared with experimental measurements in cadmium telluride and amorphous silicon modules, and with results published in the literature for other technologies. The model faithfully reproduces the experimental values. For all the modules, the root mean square error for the maximum power is lower than 2% (below 1.5% in most cases). These errors are lower than those reported in the literature for other models. In particular, the results are significantly more exact in the case of thin-film modules.

Performance evaluation of LoRa technology for agricultural applications in rural areas

This article presents the results obtained in the evaluation of the LoRa technology as an alternative communication protocol for agricultural applications, by making measurements in situ in a rural area between the municipalities of Sibaté and Granada in Cundinamarca, Colombia. The device for testing was selected using a document search, thus choosing the TTGO esp32 board. Additionally, a temperature sensor and a variable resistance were included to obtain measurements from a transmitter node whose data was sent using the LoRa protocol to a receiver node with a distance of 500 meters between them and an approximate elevation gradient of 4° difference between the points. Finally, the information collected in the tests was subjected to a descriptive statistical analysis that allowed establishing the most reliable parameters of the protocol and identifying the appropriate spreading factor and bandwidth.

Evidence for selection of multi-resistant E. coli by hospital effluent

There is a risk that residues of antibiotics and other antimicrobials in hospital and municipal wastewaters could select for resistant bacteria. Still, direct experimental evidence for selection is lacking. Here, we investigated if effluent from a large Swedish hospital, as well as influent and effluent from the connected municipal wastewater treatment plant (WWTP) select for antibiotic resistant Escherichia coli in three controlled experimental setups. Exposure of sterile-filtered hospital effluent to a planktonic mix of 149 different E. coli wastewater isolates showed a strong selection of multi-resistant strains. Accordingly, exposure to a complex wastewater community selected for strains resistant to several antibiotic classes. Exposing individual strains with variable resistance patterns revealed a rapid bactericidal effect of hospital effluent on susceptible, but not multi-resistant E. coli. No selection was observed after exposure to WWTP effluent, while exposure to WWTP influent indicated a small selective effect for ceftazidime and cefadroxil resistant strains, and only in the E. coli mix assay. An analysis of commonly used antibiotics and non-antibiotic pharmaceuticals in combination with growth and resistance pattern of individual E. coli isolates suggested a possible contribution of ciprofloxacin and β-lactams to the selection by hospital effluent. However, more research is needed to clarify the contribution from different selective agents. While this study does not indicate selection by the studied WWTP effluent, there is some indications of selective effects by municipal influent on β-lactam-resistant strains. Such effects may be more pronounced in countries with higher antibiotic use than Sweden. Despite the limited antibiotic use in Sweden, the hospital effluent strongly and consistently selected for multi-resistance, indicating widespread risks. Hence, there is an urgent need for further evaluation of risks for resistance selection in hospital sewers, as well as for strategies to remove selective agents and resistant bacteria.

Distinct properties and functions of CTCF revealed by a rapidly inducible degron system

SUMMARYCCCTC-binding factor (CTCF) is a conserved zinc finger transcription factor implicated in a wide range of functions, including genome organization, transcription activation, and elongation. To explore the basis for CTCF functional diversity, we coupled an auxin-induced degron system with precision nuclear run-on. Unexpectedly, oriented CTCF motifs in gene bodies are associated with transcriptional stalling in a manner independent of bound CTCF. Moreover, CTCF at different binding sites (CBSs) displays highly variable resistance to degradation. Motif sequence does not significantly predict degradation behavior, but location at chromatin boundaries and chromatin loop anchors, as well as co-occupancy with cohesin, are associated with delayed degradation. Single-molecule tracking experiments link chromatin residence time to CTCF degradation kinetics, which has ramifications regarding architectural CTCF functions. Our study highlights the heterogeneity of CBSs, uncovers properties specific to architecturally important CBSs, and provides insights into the basic processes of genome organization and transcription regulation.

Effects of Pre-Activation with Variable Intra-Repetition Resistance on Throwing Velocity in Female Handball Players: a Methodological Proposal.

The purpose of this study was to investigate the acute effect of pre-activation with Variable Intra-Repetition Resistance and isometry on the overhead throwing velocity in handball players. Fourteen female handball players took part in the study (age: 21.2 ± 2.7 years, experience: 10.9 ± 3.5 years). For Post-Activation Potentiation, two pre-activation methods were used: (I) Variable Intra-Repetition Resistance: 1 x 5 maximum repetitions at an initial velocity of 0.6 m·s-1 and a final velocity of 0.9 m·s-1; (II) Isometry: 1 x 5 s of maximum voluntary isometric contraction. Both methods were "standing unilateral bench presses" with the dominant arm, using a functional electromechanical dynamometer. The variable analysed was the mean of the three overhead throws. Ball velocity was measured with a radar (Stalker ATS). The statistical analysis was performed using ANOVA with repeated measures. No significant differences were found for either method (variable resistance intra-repetition: p = 0.194, isometry: p = 0.596). Regarding the individual responses, the analysis showed that 86% of the sample increased throwing velocity with the variable resistance intra-repetition method, while 93% of the sample increased throwing velocity with the isometric method. Both the variable intra-repetition resistance and isometric methods show improvements in ball velocity in female handball players. However, the authors recommend checking individual responses, since the results obtained were influenced by the short rest interval between the pre-activation and the experimental sets.

Experimental Assessment of the Lumped Lithium Ion Battery Model at Different Operating Conditions

This study investigates the electrical and thermal characteristics of a cylindrical lithium-ion cell with an axisymmetric two-dimensional lumped model. The cell is completely discharged at 0.5, 1 and 1.5 C rates under 0, 20 and 50 °C operating temperatures. Both the open circuit voltage values and the average specific heat value of the cell are measured and used as an input to the model. The model uses the variable internal resistance approach to evaluate the voltage variation of the cell that is obtained from experimental data. A cylindrical lithium-ion cell has a spiral construction that involves multiple layers. However, these layers are assumed as a uniform material in the lumped model. The lumped model in COMSOL Multiphysics couples the heat transfer and lumped battery interfaces so it allows predicting the surface temperature of the cell during discharging processes. The experimental results point out that the operating temperature inversely affects the internal resistance and the heat generation within the cell during a discharging process. Furthermore, it is found that the capacity of the cell significantly decreases at low operating temperatures. Finally, the predicted temperature profile follows the same trend with the experimental data and is consistent at each operating condition.

Comparison between traditional resistance exercise and variable resistance with elastic bands in acute vertical jump performance

PurposeResistance exercise (RE) with variable resistance (VR) may be an interesting strategy to increase strength and power in several sports activities. The present study aimed to compare the effect of RE vs. VR exercise in the back squat on subsequent jump performance at different time points.MethodsNine male elite handball athletes (age: 21.4 ± 2.1 years; body fat percentage: 10.5 ± 4.2%) undergoing in-season training participated in the study. They randomly completed 3 sets of 5 back squat repetitions at 85% of predicted one-repetition maximum (1RM) with 3-minute rests between sets. They performed RE back squat alone or VR back squat by combining 55% of 1RM using standard weight plates and 29.7 ± 2.0% of the athlete’s 1RM in fully erect position (starting position) with elastic band resistance. Countermovement jump (CMJ) test was applied at baseline, immediately after the conditioning activity (within 15 seconds), and every 2 minutes after the protocols (2, 4, 6, and 8 minutes).ResultsThere was a very large (5.8%, <i>p</i> = 0.02, <i>ES</i> = 1.53) increase in CMJ performance 2 minutes after VR back squat, while no significant changes were observed after the completion of RE back squat. Moreover, there was a large (<i>p</i> = 0.04, <i>ES</i> = 1.27) increase in peak power after VR exercise.ConclusionsCMJ performance and peak power output can be potentiated after 2 minutes of recovery following the completion of back squat exercise combining RE plus elastic bands, reinforcing the practical applicability of VR exercise.

Coagulase-negative Staphylococci And their pathogenic role: A focus on nosocomial infections

Staphylococci, involved in many human diseases, are present on human and animal body surfaces as well as in air, food and water. The general classification of staphylococci divides them in two major groups; coagulase positive and negative staphylococci. Coagulase-negative staphylococci (CoNS) are present as a part of normal skin and mucous membrane flora in humans. CoNS have long been considered as non-pathogenic organism but now they are considered pathogenic involved in infections related to prosthetic materials particularly in surgical wounds. Virulence factors in CoNS are not very clearly established. Staphylococcus epidermidis is evolving as a resistant and powerful microbe related to nosocomial infections. Characteristics like biofilm formation, drug resistance and evolution of genetic variables contribute to its pathogenicity. This review elaborates the evidence of involvement of CoNS in various clinically important infections from recent and past literature.

Farmers’ preference on the characteristics of improved variety and prospective lines of soybean seed in acidic dry-land (a case study in South Kalimantan and East Lampung)

National soybean consumption in 2018 was not in balance with its production. One of factors affecting soybean production is location-specific improved varieties utilization. The research aimed to identify farmers’ considerations in responding improved soybean varieties and prospective lines. The research was conducted in KP Taman Bogo, East Lampung and BP3T at Tambak Ulang, South Kalimantan. Data collected presented into tables. A descriptive analysis used by calculating means and percentage value. The results showed that crop height, seed shape, drought resistance, and fall resistance were the dominant considerations for East Lampung farmers. South Kalimantan farmers chose growth type, flowering age, harvest age, pod color, non-breaking pod, leaf shape, seed color, wilting symptoms, pests and diseases resistance, fall resistance, and ease of sale variables. Of the ten lines and four Iletri’s improved soybean varieties, East Lampung farmers chose Grobogan for crop phisycal performance as priority I (37.9%) and II Tgm/933 (24,2%); while South Kalimantan farmers chose Tanggamus (23.3%), Tgm/Anj-910 (26,7%) and Tgm/Anj-933 lines (30%). For seed characteristics, 51.7% of East Lampung farmers chose Grobogan as priority I, while South Kalimantan farmers chose Tgm/Anj-931 line (30.0%). It is expected that by selecting location-specific improved varieties, farmers can increase soybean production, thereby increasing their income.

Effectiveness of mantra meditation as a neurophysiological phenomenon for stress management in undergraduate medical students

Background: Meditation has widely been used to combat stress and its effects, yet the universality of its effectiveness and duration remains unclear. Aim and Objectives: This study aimed to evaluate differences in its effectiveness among individuals with different baseline stress levels and recommend duration of practice to produce constructive outcomes. Materials and Methods: A total of 30 undergraduate medical students (15 males and 15 females) with a mean age of 21 (±0.95) years volunteered for the study. Preliminarily, using the perceived stress scale (PSS), they were categorized into high (0), moderate (25), and low (5) stress groups; following which they were pre-tested for heart rate (HR), HR variability, and galvanic skin resistance (GSR), subject to a computer game stressor. Students were then instructed to undertake meditation sessions and were tested for the same parameters at intervals of 3 and 6 weeks from the pre-test. Results: Moderate stress individuals showed a significant (P ≤ 0.05) increase in high frequency band, GSR, RMSSD (square root of the mean of the sum of the squares of the differences between adjacent RR intervals) and the percentage of RR 50 counts; accompanied with a significant decrease in PSS score, low frequency to high frequency ratio and HR; with parameters becoming significant within 3 weeks of practice, and no further significant changes in the 3–6 weeks period. None of the parameters were significant for the low stress group, although similar trends were observed. Conclusion: The study indicated the usefulness of a 3-week meditation program for individuals with moderate or high stress, and recommendation to include a meditation program into the undergraduate medical curriculum. Positive effects were attributed to a shift of sympathovagal balance to parasympathetic dominance.

GEOPHYSICAL INVESTIGATIONS OF A POTENTIAL LANDSLIDE AREA IN MAYOON, HUNZA DISTRICT, GILGIT-BALTISTAN, PAKISTAN

The Mayoon landslide in the Hunza District is a slowly developed, non-catastrophic landslide that has gained its importance in the last few years after its rapid activation and fast slip rate. The area is characterized by high earthquake hazards (zone 3 with a peak ground acceleration value of 2.4–3.2 m/s2) by the Building Code of Pakistan due to frequent earth quakes. The past high earthquake activity in the area has displaced the foliated rocks towards the south and is responsible for opening the bedrock joints. The head and body of the landslide are covered by unconsolidated material and have fractures of varying lengths and widths. The non-invasive geophysical techniques, including Ground Penetrating Radar (GPR) and Electrical Resistivity Soundings (ERS), are deployed to evaluate the Mayoon landslide subsurface. The subsurface is interpreted into a two-layer model. Bright reflectors and highly variable resistivity characterize the top layer (Layer-1). This layer is associated with a loose, highly heterogeneous, fragmented material deposited under glacial settings over the existing bedrock. Hyperbolic reflections and intermediate resistivity characterize the bottom layer (Layer-2). This layer is associated with foliated metamorphic bedrock. The hyperbolic reflections show faults/fractures within the bedrock. The extension of these fractures/faults with depth is uncertain due to decay in the GPR signal with depth. The intermediate resistivity shows the bedrock is weathered and foliated. Reflections within Layer-1 have disrupted directly above the fractures/faults suggesting a possible movement. A bright reflection between the two layers highlights the presence of the debonded surface. Loose material within Layer-1 coupled with debonding possesses a significant hazard to generate a landslide under unfavourable conditions, such as an intense rainstorm or earthquake activity.

Epidemiological and Microbiological Study of Onychomycosis

Introduction: Onychomycosis is a common fungal infection of nail. It may be caused by dermatophytes, non-dermatophytic moulds or yeasts involving nail bed, nail plate or matrix of nail. As the fungi show variable susceptibility to antifungal drugs and treatment requires long duration of antifungal therapy, so it’s prevalence as well as proper laboratory diagnosis and antifungal susceptibility testing is essential for effective therapy. Aim: To find the prevalence of onychomycosis with demography along with various aetiology and the suitable antifungal drugs used for treatment. Materials and Methods: For this prospective study, over a period of two years a total of 300 nail samples were processed in the Department of Microbiology at IMS and SUM Hospital, Bhubaneswar, Odisha, India. The wet mount for microscopic examination was prepared using 20% Potassium Hydroxide (KOH) and examined after overnight incubation. Culture was done in duplicate in Sabouraud’s Dextrose Agar (SDA) tubes; one with actidione and another without it and both were incubated at 25°C in Biological Oxygen Demand (BOD) incubator. Culture tubes growing yeasts were further subjected to speciation by germ tube test, culture on Chromogenic (CHROM) agar and on cornmeal agar. In-vitro antifungal susceptibility testing was performed against Candida species using disc diffusion method on Muller Hinton agar. Chi-square test was used for statistical analysis of the results. Results: Onychomycosis can affect a wide age group though seen commonly at 31-40 years equally in both male and females. Fingernail infection was observed mostly in female cases. It was caused by Candida species (66%), moulds (24%) and dermatophytes (10%) and out of Candida sp. C.albicans was the main culprit. Although all the Candida strains were susceptible to amphotericin B, still some of them showed resistance to the commonly used antifungals like fluconazole and itraconazole. Conclusion:Candida albicans was the most common aetiological agent which contributed for onychomycosis and showed a variable resistance pattern to the commonly used antifungals. Proper laboratory diagnosis and selection of antifungal drug is essential prior to institution of therapy for successful treatment of this disease.

Spectrum and Antibiotic Resistance Pattern of Uropathogens Causing Urinary Tract Infection Among Inpatients and Outpatients: An Experience of a Tertiary Care Hospital in Karachi, Pakistan

Objective: To determine the spectrum and antibiotic resistance pattern of uropathogens causing urinary tract infection among inpatients and outpatients in a tertiary care hospital in Karachi Methods: This descriptive cross-sectional study was conducted in the Department of Microbiology, Sindh Institute of Urology and Transplant, Karachi, The study was conducted from March 2016 to March 2017 after taking approval from the Hospital Ethics Committee. Urine specimens were analyzed to establish a diagnosis of UTI and identify uropahtogens. The antibiotic susceptibility pattern of uropathogens was studied using disc diffusion method against the following antibiotics; fosfomycin, ampicillin, amoxicillin-clavulanate, nitrofurantoin, cefotaxime, ceftazidime, amikacin, cefoxitin, imipenem and vancomycin. Results: A total of 480 samples of UTI were received during the study period. The average age of patients was 54.79±12.09 years. The majority of samples came out positive from the male gender (65%) and in-patient department (n=400, 83.3%). The highest prevalent microorganism was E.coli (82.1%) followed by Klebsiella spp (14%), Pseudomonas aeruginosa (1%), Proteus mirabilis (1%), Morganella morgannii (1%) and Staphylococcus aureus (0.8%). All microorganisms were highly resistant to augmentin, cefoxitin, cefotaxime, ceftazidime. Only pseudomonas aeruginosa was highly resistant to imipenem (60%). Pseudomonas aeruginosa (100%), E.coli (86.8%) and Klebsiella spp (71.6%) were highly sensitive for Amikacin (100%). Morganella morgannii (80%) and Proteus Mirabilis (40%) were mainly resistant to Fosfomycin. Only E.coli was sensitive to nitrofurantoin (74.1%). Conclusion: The presented study demonstrated that gram-negative bacteria was the most frequent cause of urinary tract infection. Microorganisms showed variable resistance to different antibiotics. The first line of antibiotics should be rationally selected by physicians to treat urinary tract infections.

Evaluation of preoperative naso-alveolar molding in correction of unilateral complete cleft lip and palate associated with nasal deformity

Background Deviated nasal septum causes variable resistance to inspired air currents, which directly and indirectly influences the efficiency of pulmonary functions. Aim To compare pulmonary function tests performed before and following septoplasty with turbinectomy in patients complaining of nasal obstruction caused by a deviated septum with hypertrophic inferior turbinate. Patients and methods The study was conducted on 60 patients diagnosed with deviated nasal septum with hypertrophied inferior turbinate. All were subjected to complete history taking, external nasal examination, and anterior rhinoscopy, which was performed with a nasal speculum. Additionally, all patients in this study underwent a nasal endoscopy, computed tomography, and spirometry. Septoplasty and turbinectomy were performed for all cases with regular follow‑up, and the spirometry was repeated after 3 months. Results After surgery, the preoperative forced vital capacity (FVC) of 3.14±0.70 increased to 4.43±1.01, with a highly statistically significant difference (P<0.001). Forced expiratory volume in the first second (FEV1) was significantly greater postoperatively (2.66±0.55) than preoperatively (3.96±0.81) (P<0.001). The preoperative FEV1/FVC ratio of 85.08±5.47% improved to 90.39±8.75% after surgery, with a statistically significant increase (P=0.001). The preoperative peak expiratory flow rate of 5.57±1.47 increased to 7.07±2.26 following surgery, a difference that was highly statistically significant (P<0.001). The preoperative forced expiratory flow of 25–75% of vital capacity of 2.73±1.13 increased to 3.73±1.28 after surgery, a change that was highly statistically significant (P<0.001). Conclusion FVC, FEV1, FEV1/FVC, PEF, and forced expiratory flow of 25–75% showed a significant increase after operation. Keywords: pulmonary function, septoplasty, turbinectomy.

Impact of Stray Voltage on Renewable Energy-based Farm in Pacific Island Country

Recent advancements in solar technology offer an enormous opportunity for the people of Pacific Islands to use electricity from the off-grid solar system for both their energy needs and farming activities. However, a farm’s productivity and animal health might be seriously threatened if it experiences stray voltages caused by the improper grounding of its installed electrical systems. As a shift in the neutral point of an electrical system creates a current flow to the ground through conducting elements, the impacts of stray voltages need to be addressed from both technical and economic viewpoints. In this research, the effects of stray voltages passing through animals are explored using circuit designs for solar sources considering variable grounding resistances due to the different body resistances of various types of animals, and environmental and grounding design issues. A comparison of the stray voltages of two different sources (off-grid solar and traditional grid) with various configurations are conducted to determine their effects on a farm. Finally, their economic impacts together with possible techniques for mitigating them are explained.

1275. Evaluation of in vitro activity of manogepix against multidrug-resistant and pan-resistant Candida auris from the New York Outbreak

BackgroundAn ongoing Candida auris outbreak in the New York metropolitan area is the largest recorded to date in North America. NY C. auris isolates demonstrate resistance to fluconazole and variable resistance to other antifungals. Thus, there is an urgent need for new drugs with a novel mechanism of action to combat the resistance challenge. Manogepix (MGX) is a first-in-class agent that targets the fungal Gwt1 enzyme. The prodrug, fosmanogepix, is in clinical development for the treatment of invasive fungal infections.MethodsWe evaluated the susceptibility of 200 NY C. auris isolates (2017-2020) to MGX and 10 comparators. Testing was performed using TREK frozen broth microdilution panels for FLC, VRC, ITC, ISA, POS, AFG, CAS, and MFG. MGX MICs were evaluated (CLSI M27-A3 guidelines) using a 50% reduction in fungal growth endpoint at 24 h. MICs were determined by ETEST® at 24 h for AMB and FLC. We defined pan-resistant C. auris as isolates with in vitro resistance to two or more azoles, all echinocandins, and AMB. The epidemiological cutoff values (ECVs, ECOFFs) for MGX were estimated using the Microsoft Excel spreadsheet calculator ECOFFinder.ResultsMGX demonstrated lower MICs than comparators (MIC50 and MIC90 0.03 mg/L; range 0.004-0.06 mg/L). MGX was 8-32-fold more active that the echinocandins, 16-64-fold more active than the azoles, and 64-fold more active than AMB. No differences were found in the MGX or comparators’ MIC50, MIC90, or GEOMEAN values when subsets of clinical, surveillance, and environmental isolates were evaluated. The range of MGX MIC values for six C. auris pan-resistant isolates was 0.008-0.015 mg/L, and the median and mode MIC values were 0.015 mg/L, demonstrating that MGX retains activity against these isolates. The MGX epidemiological cutoff value (ECV, 99% cutoff) was 0.06 mg/L.ConclusionMGX MICs were low against C. auris isolates including those with variable patterns of resistance to AMB, azoles, and echinocandins. In addition, MGX retained potent activity against six pan-resistant isolates. These data support the continued clinical evaluation of fosmanogepix for the treatment of C. auris infections, including highly resistant isolates.DisclosuresKaren J. Shaw, PhD, Amplyx (Consultant)Forge Therapeutics (Consultant) Vishnu Chaturvedi, PhD, Amplyx (Grant/Research Support)

Study of the Quaternary Deposits at the East and West Shoulders of Mosul Dam Using Azimuthal 2D Resistivity Imaging

The field survey included three geoelectric traverses on the eastern side of the Tigris River parallel and perpendicular on the axis of the Tairah anticline consisting of seven sites of ( Azimuthal Resistivity Tomography; ART) located above the Quaternary depositions in the southern flank. Two traverses were also conducted in the western side of the river parallel and perpendicular on the east Butmah anticline consisting of four sites located above the recent sediments in the southern flank of it. The sites are chosen taking into account the consideration of the geological, tectonic and topographic data of previous studies and current field reconnaissance trips. A sympathetic analysis of the resistivity tomography is performed in nine azimuths of the above mentioned locations using fifteen repetitive processing attempts and the mean root squares ranged between 5.8% -11.7%. The eastern side of the study area with different directions indicates electrical horizons, the first reflects a variable resistivity which represents accumulations of top soil, the second band of high resistivity which reflects the river terraces constitutes, while the third horizon represents the clear extension of the mud and limestone deposits of Fatha Formation with a vertical conductive zones in the rock layers at some traverses. As well as the ART on the western side of the study region identified three electric horizons: the first with high resistivity reflecting the surface soil layer, and the second domain of low resistivity representing the sediments of the valley slopes and concentrating on the southern limb of Butmah anticline. The third of heterogeneous resistivity values reflects Fatha Formation deposits covering its exposures at the core of the two anticlines and locating beneath the research traverses. Using the technology of 2D resistivity imaging reveals that the nine orientations around a central point in eleven locations above recent sediments are represented by river terraces and alluvial deposits on the shoulders of the Mosul Dam. The current study concludes the ability to capture fractures, which is of great importance due to their effect on the displacements of the dam's body and Fatha sediments surrounding it.

Commentary on a method for testing resistance to shocks

This note tours the Narayan (2020a: Has COVID-19 Changed Exchange Rate Resistance to Shocks?) approach to testing for resistance of a time-series variable to shocks. We take a step-by-step account of this approach and demonstrate its applicability with respect to the crude oil price.•The approach entails steps (1) to (8), as outline in the paper.•Future researchers will find this method useful in evaluating the resistance of variables to not only COVID-19 shocks but to any shock which has had a sufficiently long life.

Adaptive Energy Estimation for Supercapacitor Based on a Real-Time Voltage State Observer in Electric Vehicle Applications

As an energy storage or power buffering device, supercapacitor (SC) has incomparable advantages in terms of charging-discharging efficiency, response speed, and durability. Generally, a simplified energy estimation method based on a constant or rated capacitance can be used to evaluate the state-of-energy (SoE) of SCs. However, using a constant capacitance to evaluate the SoE of SC is very imprecise. Indeed, the SC internal parameters would change in accordance with the operating current and voltage such that the actual capacitance is far from the rated capacitance. This letter presents: a variable first-order resistance-capacitance equivalent circuit for dynamic modeling of the SC; a real-time voltage state observer used to estimate the variable internal capacitance and resistances of the SC; three different energy estimation methods; and simulated and experimental validations of the adaptive energy estimation method based on a 3000 F SC in electric vehicle applications. By using the SoE based on an experiment calibration as a reference standard, the proposed adaptive energy estimation method can improve over 0.75% of the estimated SoE error for the SC compared with the conventional estimation method.

Pregnancy and asymptomatic bacteriuria- A study from a tertiary care teaching hospital, Hyderabad

Introduction: Asymptomatic bacteriuria is found in 2 to 10% of pregnant women. Complications like acute pyelonephritis, postpartum UTI, hypertension, anemia, prematurity, low birth weight babies and prenatal death may occur if untreated. Hence early detection and treatment are of considerable importance. Materials and Methods: A crosssectional study was conducted for a period of one year. A clean catch midstream urine sample was collected from pregnant women as a part of routine antenatal screening. The samples were processed according to standard microbiological techniques –wet mount examination, gram staining, glucose test paper, culture and antibiotic susceptibility testing. Results: Of the 200 samples received from the study group, 28(14%) were culture positive. The prevalence of culture positivity was more in the third trimester (19.4%).The predominant organisms isolated were gram negative bacteria like Escherichia coli (35.7%) and Klebsiella spp (28.5%). E.coli and Klebsiella showed variable resistance to fluoroquinolones, cephalosporins, aminoglycosides, betalactam and betalactam inhibitor combination. However the isolates of E.coli were sensitive to carbapenams and polymixins. Isolates of Klebsiella spp were sensitive to Polymixins. The predictive accuracy of different screening tests with culture was calculated. The sensitivity, specificity, positive predictive value, negative predictive value of grams staining is more compared to urine wet mount examination and urine test paper method in early detection of bacteruria. Conclusion: Early detection and treatment for asymptomatic bacteriuria is of considerable importance as 40% of asymptomatic cases develop into pyelonephritis The choice of antibiotic should be based on urine culture, stage of gestation, clinical data and the characteristics of the antibiotic. Keywords: Asymptomatic bacteriuria, Antenatal women, prevalence, Glucose test paper, Urine culture, Wetmount examination, Gram staining, Perinat