Understanding the saturation power of Josephson Parametric Amplifiers made from SQUIDs arrays

We report on the implementation and detailed modelling of a Josephson Parametric Amplifier (JPA) made from an array of eighty Superconducting QUantum Interference Devices (SQUIDs), forming a non-linear quarter-wave resonator. This device was fabricated using a very simple single step fabrication process. It shows a large bandwidth (45 MHz), an operating frequency tunable between 5.9 GHz and 6.8 GHz and a large input saturation power (-117 dBm) when biased to obtain 20 dB of gain. Despite the length of the SQUID array being comparable to the wavelength, we present a model based on an effective non-linear LC series resonator that quantitatively describes these figures of merit without fitting parameters. Our work illustrates the advantage of using array-based JPA since a single-SQUID device showing the same bandwidth and resonant frequency would display a saturation power 15 dB lower.Comment: 12 pages, 9 figures, Appendices include

Stochastic energetics of a colloidal particle trapped in a viscoelastic bath

We investigate the statistics of the fluctuations of the energy transfer between an overdamped Brownian particle, whose motion is confined by a stationary harmonic potential, and a surrounding viscoelastic fluid at constant temperature. We derive an analytical expression for the probability density function of the energy exchanged with the fluid over a finite time interval, which implicitly involves the friction memory kernel that encodes the coupling with such a non-Markovian environment, and reduces to the well known expression for the heat distribution in a viscous fluid. We show that, while the odd moments of this distribution are zero, the even moments can be explicitly expressed in terms of the auto-correlation function of the particle position, which generally exhibits a non-mono-exponential decay when the fluid bath is viscoelastic. Our results are verified by experimental measurements for an optically-trapped colloidal bead in semidilute micellar and polymer solutions, finding and excellent agreement for all time intervals over which the energy exchange takes place.Comment: 3 figure

Typing methods used in the molecular epidemiology of microbial pathogens: a how-to guide

Microbial typing is often employed to determine the source and routes of infections, confirm or rule out outbreaks, trace cross-transmission of healthcare-associated pathogens, recognize virulent strains and evaluate the effectiveness of control measures. Conventional microbial typing methods have occasionally been useful in describing the epidemiology of infectious diseases. However, these methods are generally considered too variable, labour intensive and time-consuming to be of practical value in epidemiological investigations. Moreover, these approaches have proved to be insufficiently discriminatory and poorly reproducible. DNA-based typing methods rely on the analysis of the genetic material of a microorganism. In recent years, several methods have been introduced and developed for investigation of the molecular epidemiology of microbial pathogens. Each of them has advantages and limitations that make them useful in some studies and restrictive in others. The choice of a molecular typing method therefore will depend on the skill level and resources of the laboratory and the aim and scale of the investigation. This study reviews the most popular DNA-based molecular typing methods used in the epidemiology of bacterial pathogens together with their advantages and limitations

Compliance with wearing a thoracolumbar orthosis in nonoperative treatment of osteoporotic vertebral fractures: A prospective sensor-controlled study

BACKGROUND CONTEXT Hyperextension orthoses (HOs) for non-operative treatment of osteoporotic vertebral fractures (OVFs) are widely prescribed. However, the compliance, how much an HO is worn after it has been prescribed, is widely unknown. PURPOSE This study was performed to assess the wearing time of HOs for OVFs in a prospective blinded, sensor-controlled manner. STUDY DESIGN / SETTING A prospective, single blinded observational study was performed. PATIENT SAMPLE This study prospectively included 18 patients who were treated non-operatively with an HO for OVFs. OUTCOME MEASURES The true wearing time was measured using a hidden temperature-based sensor. The patients were invited to return for regular follow-up every 2 weeks for 6 weeks, at which time clinical evaluation (including a visual analog scale for pain and the Oswestry disability questionnaire) and radiographs of the spine were performed. METHODS Full compliance was defined as a wearing time of 15 hours per day. Correlation between compliance and demographic differences, patient reported outcomes and radiographic changes of the vertebral structures were calculated. RESULTS The mean HO wearing time was 5.5±3.3 hours (37%±22% compliance). Female patients used the HO significantly longer per day than did male patients (6.5±3.2 vs 2.9±2.0 hours, p=.039). Age and body mass index had no influence on wearing behavior. CONCLUSIONS Overall, compliance with wearing HOs is poor and shows great variability with significant gender-dependency but not associated with BMI, age, or pain-level. Further studies are required to confirm our results that the wearing time does not have an influence on kyphotic progression of the osteoporotic fractured segment, nor on clinical outcome at short term. LEVEL OF EVIDENCE I

Effect of travelling fire on structural response of a generic steel fire protected moment resisting frame

To simulate a fire inside large compartments, there is a pioneering method called ‘traveling fire’. As steel structures are vulnerable to high temperatures, they are normally fireproofed by insulation materials appropriate for a specific duration of time. An investigation is performed here to examine the robustness of a generic fourstory moment-resisting steel structure, fireproofed to comply with the one-hour standard curve, when it is subjected to traveling fire. The results show that while no collapse occurs during the 12.5%, 50% and 100%, the structure collapses under the 25% fire size at 75 min. This seems to be in contradiction with traditional belief, where it is assumed that taking into consideration a larger-scale fire in a compartment would increase the safety margin. The investigation performed also underlines that the fireproofing of structures does not necessarily provide adequate resistance under traveling fires

Promjena indikatora kvalitete električne energije trošila predstavljanjem adaptivne metode za upravljanje DVR-om zasnovane na Hebbovom algoritmu učenja

Having electricity with high quality is one of the more important aims in electrical systems. Disturbances in distribution systems can change voltage waveform. There are some methods to prepare high power quality for sensitive loads. In this research we use “Dynamic Voltage Restorer” to compensate the harmful effects of disturbances on voltage. Since power systems fundamentally have complicated dynamic behavior, especially during faults, “Hebb” learning self-tuning controller, which is a powerful adaptive controller, has been used. In order to improve the performance of this controller from point of view of power quality’s indices, such as flash and sensitive load voltage THD, a new structure is proposed for this controller with fuzzification method. Simulation results indicate better operation of the system for the case of proposed controller. Voltage sag and harmonics in faulty conditions are both improved by the proposed controller. According to simulation results, it works better than both classical PI controller and conventional Hebb learning controller.Jedan od važnijih ciljeva elektroenergetskog sustava visoka je kvaliteta električne energije. Poremećaji u distribucijskom sustavu mogu neželjeno izmijeniti valni oblik napona. Postoji nekoliko metoda kako osigurati visoku kvalitetu energije za osjetljiva trošila. U istraživanju koristimo "dinamičku obnovu napona" za kompenziranje štetnih efekata poremećaja u naponu. Kako energetski sustavi u osnovi imaju složeno dinamičko ponašanje, posebno tijekom kvarova, korišten je vrlo moćan adaptivni regulator: "Hebbov" samopodešavajući regulator sa sposobnošću učenja. Da bi se unaprijedilo vladanje spomenutog regulatora s aspekta indikatora kvalitete energije kao što su parcijalna izbijanja i THD osjetljivog trošila, predložena je nova struktura regulatora s uključenim metodama neizrazite logike. Simulacijski rezultati pokazuju bolji rad sustava uz korištenje predloženog regulatora. Regulator smanjuje propade napona i poboljšava harmonični sastav sustava u kvarnim uvjetima. Rezultati simulacija također pokazuju bolje ponašanje u odnosu na uobičajeni PI regulator te konvencionalni Hebbov regulator s učenjem

Evaluation of Different Best Management Practices for Erosion Control on Machine Operating Trails

Ground-based mechanized forest operations often lead to increased runoff and soil loss on unbound forest roads and machine operating trails, which in turn can impede the technical trafficability of machines and cause negative impacts on the environment. The aim of this study was to evaluate the effectiveness of three Best Management Practice (BMP) treatments used to control erosion occurring on machine operating trails. The treatments included water bar, water bar and hardwood brush (H-brush), and water bar and softwood brush (S-brush). For a more comprehensive assessment of both brush treatments, two levels of brush thickness were tested; 0.5 m and 1.0 m. Results indicate that the most effective BMP treatments were the water bar and softwood brush followed by the water bar and hardwood brush and finally the least effective was the water bar. The average runoff rates and soil loss from the machine operating trails with the water bar treatment (52.64 l per plot, 8.49 g m-2) were higher than runoff and soil loss at the trails protected with hardwood brush (23.75 l per plot, 4.5 g m-2), and the trails protected by the hardwood brush had higher runoff and soil loss compared to trails covered by softwood brush (15.83 l per plot, 2.98 g m-2). Furthermore, results of this study showed that regardless of the treatment, the amount of runoff and soil loss decreased consistently as the thickness of the brush mat increased. Overall, erosion control techniques similar to either H-brush or S-brush that provide direct soil coverage should be used for erosion control, and final selection should be based on costs, availability of material, or landowner objectives

Characterization of radio active aerosols in Tehran research reactor containment

The objectives of this research were to determine the levels of radioactivity in the Tehran research reactor containment and to investigate the mass-size distribution, composition, and concentration of radio nuclides during operation of the reactor. A cascade impactor sampler was used to determine the size-activity distributions of radioactive aerosols in each of the sampling stations. Levels of α and β activities were determined based on a counting method using a liquid scintillation counter and smear tests. The total average mass fractions of fine particles (particle diameter dp <1 µm) in all of the sampling stations were approximately 26.75 , with the mean and standard deviation of 52.15 ± 19.75 µg/m3. The total average mass fractions of coarse particles were approximately 73.2, with the mean and standard deviation of 71.34 ± 24.57 µg/m3. In addition to natural radionuclides, artificial radionuclides, such as 24Na,91Sr,131I,133I,103Ru,82Br, and 140La, may be released into the reactor containment structure. Maximum activity was associated with accumulation-mode particles with diameters less than 400 nm. The results obtained from liquid scintillation counting suggested that the mean specific activity of alpha particles in fine and coarse-modes were 89.7 and 10.26 , respectively. The mean specific activity of beta particles in fine and coarse-modes were 81.15 and 18.51 , respectively. A large fraction ofthe radionuclides' mass concentration in the Tehran research reactor containment was associated with coarse-mode particles, in addition, a large fraction of the activity in the aerosol particles was associated with accumulation-mode particles. © 2015, Vinca Inst Nuclear Sci. All rights reserved

The Prevalence of Needle sticks injuries among health care workers at a hospital in Tehran

ABSTRACT Needle stick injuries (NSIs) are one of the most significant and preventable hazards in relation to Healthcare workers (HCWs). Such injuries have been shown to be of high prevalence within developing countries. To determine the prevalence and circumstances pertaining to the occurrence of NSIs among HCWs employed at a special hospital. The study conducted was a cross-sectional study on HCWs and was carried out in one of Tehran's special hospitals in the year 2012. In this study, in order to identify and determine hazardous potential due to needle stick, HFMEA method was chosen. This resulted in the collection of 240 valid and reliable questionnaires. The validity and reliable nature of the questionnaires was confirmed by experts and by means of the test re-test method. The gathered data was analyzed with SPSS software, version 16.From the analysis of the data it was shown that, a total of 97 (40.42%) HCWs had suffered NSIs in the last year. The patient ward showed the highest prevalence of NSIs (47.42%) in the hospital. Nurses had the highest risk of suffering NSIs (56.7%) in comparison with the other occupational groups. All in all 175 NSIs occurred for the 240 HCWs trialed during the selected period of clinical practice. Of those that received injuries, only roughly 1 in 3 (38.14%) reported it to their infection control officer. Just over a quarter (26.80%) of the injured HCWs used post exposure prophylaxis (PEP) against HIV. Almost all (88.75%) of the HCWs had received a safe injection course. In general, NSIs and their subsequent underreporting are commonplace among hospital healthcare professionals. Significantly, more than two-thirds of the injured HCWs did not use post-exposure prophylaxis (PEP) against HIV. Improved prevention and reporting strategies are needed if the occupational health and safety of healthcare workers is to improve

A database and tool, IM Browser, for exploring and integrating emerging gene and protein interaction data for Drosophila

BACKGROUND: Biological processes are mediated by networks of interacting genes and proteins. Efforts to map and understand these networks are resulting in the proliferation of interaction data derived from both experimental and computational techniques for a number of organisms. The volume of this data combined with the variety of specific forms it can take has created a need for comprehensive databases that include all of the available data sets, and for exploration tools to facilitate data integration and analysis. One powerful paradigm for the navigation and analysis of interaction data is an interaction graph or map that represents proteins or genes as nodes linked by interactions. Several programs have been developed for graphical representation and analysis of interaction data, yet there remains a need for alternative programs that can provide casual users with rapid easy access to many existing and emerging data sets. DESCRIPTION: Here we describe a comprehensive database of Drosophila gene and protein interactions collected from a variety of sources, including low and high throughput screens, genetic interactions, and computational predictions. We also present a program for exploring multiple interaction data sets and for combining data from different sources. The program, referred to as the Interaction Map (IM) Browser, is a web-based application for searching and visualizing interaction data stored in a relational database system. Use of the application requires no downloads and minimal user configuration or training, thereby enabling rapid initial access to interaction data. IM Browser was designed to readily accommodate and integrate new types of interaction data as it becomes available. Moreover, all information associated with interaction measurements or predictions and the genes or proteins involved are accessible to the user. This allows combined searches and analyses based on either common or technique-specific attributes. The data can be visualized as an editable graph and all or part of the data can be downloaded for further analysis with other tools for specific applications. The database is available at CONCLUSION: The Drosophila Interactions Database described here places a variety of disparate data into one easily accessible location. The database has a simple structure that maintains all relevant information about how each interaction was determined. The IM Browser provides easy, complete access to this database and could readily be used to publish other sets of interaction data. By providing access to all of the available information from a variety of data types, the program will also facilitate advanced computational analyses