| 1. |
- Bertilsson, Johan, et al.
(författare)
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Stress Levels Escalate When Repeatedly Performing Tasks Involving Threats
- 2019
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Ingår i: Frontiers in Psychology. - : Frontiers Media SA. - 1664-1078. ; 10, s. 1562-1562
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Tidskriftsartikel (refereegranskat)abstract
- Police work may include performing repeated tasks under the influence of psychological stress, which can affect perceptual, cognitive and motor performance. However, it is largely unknown how repeatedly performing stressful tasks physically affect police officers in terms of heart rate and pupil diameter properties. Psychological stress is commonly assessed by monitoring the changes in these biomarkers. Heart rate and pupil diameter was measured in 12 male police officers when performing a sequence of four stressful tasks, each lasting between 20 and 130 s. The participants were first placed in a dimly illuminated anteroom before allowed to enter a brightly lit room where a scenario was played out. After each task was performed, the participants returned to the anteroom for about 30 s before performing the next sequential task. Performing a repeated sequence of stressful tasks caused a significant increase in heart rate (p = 0.005). The heart rate started to increase already before entering the scenario room and was significantly larger just after starting the task than just before starting the task (p < 0.001). This pattern was more marked during the first tasks (p < 0.001). Issuance of a verbal "abort" command which terminated the tasks led to a significant increase of heart rate (p = 0.002), especially when performing the first tasks (p = 0.002). The pupil diameter changed significantly during the repeated tasks during all phases but in a complex pattern where the pupil diameter reached a minimum during task 2 followed by an increase during tasks 3 and 4 (p ≤ 0.020). During the initial tasks, the pupil size (p = 0.014) increased significantly. The results suggest that being repeatedly exposed to stressful tasks can produce in itself an escalation of psychological stress, this even prior to being exposed to the task. However, the characteristics of both the heart rate and pupil diameter were complex, thus, the findings highlight the importance of studying the effects and dynamics of different stress-generating factors. Monitoring heart rate was found useful to screen for stress responses, and thus, to be a vehicle for indication if and when rotation of deployed personnel is necessary to avoid sustained high stress exposures.
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| 2. |
- Bertilsson, Ulf, 1948, et al.
(författare)
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The Kivik tomb: Bredarör enters into the digital arena - documented with OLS, SfM and RTI
- 2017
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Ingår i: New Perspectives on the Bronze Age : proceedings of the 13th Nordic Bronze Age Symposium held in Gothenburg 9th to 13th June 2015 / edited by Sophie Bergerbrant and Anna Wessman. - Oxford : Archaeopress. - 9781784915988
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Konferensbidrag (refereegranskat)abstract
- The Bredarör cairn in Kivik sparked the interest of researchers by presenting the rare combination of rock art within a burial con- text. A recent documentation project that employed the traditional tracing method has sparked a new debate about the precision of older tracings and frottages. This paper presents the results of a holistic recording of the slabs in the Bredarör cairn using three modern methods: Structure from Motion (SfM), Optical Laser Scanning (OLS) and Reflectance Transformation Imaging (RTI). In discussing SfM, OLS and RTI, the paper demonstrates the power of these tools to expand the capabilities to record rock art in an unbiased fashion and in greater detail. In contrast to older methods, the depth and texture of features on the rock are documented and human error is reduced, because everything is recorded. Some observations of the earlier documentation efforts were confirmed, and more details added, such as information on ship prows and horse design. This allowed an in-depth discussion of the dating and use of rock art in the Bredarör cairn. It is argued that although there is evidence that the slabs were transformed several times, the majority of the carving activity was carried out during Period II of the Nordic Bronze Age. It suggests that an important individual, possibly connected to long-distance trade, was interred in the cairn that subsequently served as a necropolis until the Late Bronze Age.
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| 3. |
- Persson, Johan, et al.
(författare)
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Geometrical Optimization of Jetting Duct
- 2020
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Ingår i: 2020 8th International Electrical Engineering Congress (iEECON). - : IEEE. - 9781728130767 ; , s. 1-3
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Konferensbidrag (refereegranskat)abstract
- This paper presents and evaluates three new designs of fibre optic cable ducts for jetting. The three designs are longitudinal ridges with square, triangular and semicircular geometries. The effects of the geometries are evaluated with regards to electrostatic force, fluid drag force and jetting length with limited push force. An optimal design is suggested, with triangular longitudinal ridges on the inner surface of the duct.
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| 4. |
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| 5. |
- Akram, Shazad, et al.
(författare)
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Battery powered inductive welding system for electrofusion joints in optical fiber microducts
- 2021
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Ingår i: Electronics. - : MDPI AG. - 2079-9292. ; 10:6
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Tidskriftsartikel (refereegranskat)abstract
- Optical fiber microducts are joined together by mechanical joints. These mechanical joints are bulky, require more space per joint, and are prone to air pressure leakage and water seepage during service. A battery powered electrofusion welding system with a resistive-type joint has been recently developed to replace mechanical joints. These resistive-type electrofusion joints require physical connectors for power input. Due to a different installation environment, the power input connectors of resistive optical fiber microduct joints may corrode over time. This corrosion of connectors will eventually cause water seepage or air pressure leakage in the long run. Moreover, due to connector corrosion, resistive-type optical fiber microduct joints cannot be re-heated in future if the need arises. In this study, an inductively coupled electrofusion-type joint was proposed and investigated. This inductive-type electrofusion joint is not prone to long-term corrosion risk, due to the absence of power connectors. Inductive-type electrofusion joints can be re-heated again for resealing or removal in the long run, as no metal part is exposed to the environment. The battery powered inductive welding system can be easily powered with a 38 volts 160 watt-hour battery. The inductive-type electrofusion joint was welded within one second, and passed a 300-newton pull strength test and a 10-bar air pressure leakage test. It was demonstrated that the power input requirement for inductive electrofusion joints is 64% higher than that of resistive electrofusion joints. However, these inductive joints are relatively easy to manufacture, inexpensive, have no air leakage, and no water seepage risk in highly corrosive environments.
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| 6. |
- Akram, Shazad, et al.
(författare)
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Capacitive and optical sensing for automatic detection and characterization of cleaning sponges in fiber optic microduct installations
- 2019
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Ingår i: Proceedings - 2019 8th International Workshop on Advances in Sensors and Interfaces, IWASI 2019. - : IEEE. - 9781728105574 ; , s. 274-278
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Konferensbidrag (refereegranskat)abstract
- Optical fiber duct installation requires blowing of cleaning sponges for dirt and moisture removal before blowing the fiber cables. The traditional method requires one operator that blows the sponge and one operator in the receiving end that manually evaluate the sponges until a dry sponge is received. The proposed system eliminates the need of a second operator by introducing a solution for automatic sponge detection and characterization of moisture in sponges at the receiving end. An optical sensor is used for detection and a capacitive sensor is developed to measure the sponge's wetness. Sensor data is automatically transmitted back to the operator at the feeding end via a mobile phone. The system is characterized to work with sponges ranging from saturated with wetness to what is deemed as dry.
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| 7. |
- Akram, Shazad, et al.
(författare)
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Design and Development of a Battery Powered Electrofusion Welding System for Optical Fiber Microducts
- 2020
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Ingår i: IEEE Access. - 2169-3536. ; 8, s. 173024-173043
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Tidskriftsartikel (refereegranskat)abstract
- At present, optical fiber microducts are coupled together by mechanical types of joints. Mechanical joints are thick, require a large space, and reduce the installation distance in multi-microduct installation. They may leak or explode in the blown fiber installation process. Mechanical joints are subjected to time dependent deterioration under long service times beneath the earth's surface. It may start with a small leakage, followed by damage due to water freezing inside the optical fiber microduct. Optical fiber microducts are made up of high-density polyethylene, which is considered most suitable for thermoelectric welding. For thermoelectric welding of two optical fiber microducts, the welding time should be one second, and should not cause any damage to the inner structure of the microducts that are being coupled. To fulfill these requirements, an LTspice simulation model for the welding system was developed and validated. The developed LTspice model has two parts. The first part models the power input to joule heating wire and the second part models the heat propagation inside the different layers of the optical fiber microduct and surrounding joint by using electro-thermal analogy. In order to validate the simulation results, a battery powered prototype welding system was developed and tested. The prototype welding system consists of a custom-built electrofusion joint and a controller board. A 40 volt 4 ampere-hour Li-Ion battery was used to power the complete system. The power drawn from the battery was controlled by charging and discharging of a capacitor bank, which makes sure that the battery is not overloaded. After successful welding, a pull strength test and an air pressure leakage test were performed to ensure that the welded joints met the requirements set by the mechanical joints. The results show that this new kind of joint and welding system can effectively replace mechanical joints in future optical fiber duct installations.
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| 8. |
- Akram, Shazad, et al.
(författare)
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LTspice electro-thermal model of joule heating in high density polyethylene optical fiber microducts
- 2019
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Ingår i: Electronics. - : MDPI AG. - 2079-9292. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- At present, optical fiber microducts are joined together by mechanical type joints. Mechanical joints are bulky, require more space in multiple duct installations, and have poor water sealing capability. Optical fiber microducts are made of high-density polyethylene which is considered best for welding by remelting. Mechanical joints can be replaced with welded joints if the outer surface layer of the optical fiber microduct is remelted within one second and without thermal damage to the inner surface of the optical fiber duct. To fulfill these requirements, an electro-thermal model of Joule heat generation using a copper coil and heat propagation inside different layers of optical fiber microducts was developed and validated. The electro-thermal model is based on electro-thermal analogy that uses the electrical equivalent to thermal parameters. Depending upon the geometric shape and material properties of the high-density polyethylene, low-density polyethylene, and copper coil, the thermal resistance and thermal capacitance values were calculated and connected to the Cauer RC-ladder configuration. The power input to Joule heating coil and thermal convection resistance to surrounding air were also calculated and modelled. The calculated thermal model was then simulated in LTspice, and real measurements with 50 µm K-type thermocouples were conducted to check the validity of the model. Due to the non-linear transient thermal behavior of polyethylene and variations in the convection resistance values, the calculated thermal model was then optimized for best curve fitting. Optimizations were conducted for convection resistance and the power input model only. The calculated thermal parameters of the polyethylene layers were kept intact to preserve the thermal model to physical structure relationship. Simulation of the optimized electro-thermal model and actual measurements showed to be in good agreement.
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| 9. |
- Alassaad, Anna, 1977-, et al.
(författare)
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A tool for prediction of risk of rehospitalisation and mortality in the hospitalised elderly : secondary analysis of clinical trial data
- 2015
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To construct and internally validate a risk score, the '80+ score', for revisits to hospital and mortality for older patients, incorporating aspects of pharmacotherapy. Our secondary aim was to compare the discriminatory ability of the score with that of three validated tools for measuring inappropriate prescribing: Screening Tool of Older Person's Prescriptions (STOPP), Screening Tool to Alert doctors to Right Treatment (START) and Medication Appropriateness Index (MAI). Setting: Two acute internal medicine wards at Uppsala University hospital. Patient data were used from a randomised controlled trial investigating the effects of a comprehensive clinical pharmacist intervention. Participants: Data from 368 patients, aged 80 years and older, admitted to one of the study wards. Primary outcome measure: Time to rehospitalisation or death during the year after discharge from hospital. Candidate variables were selected among a large number of clinical and drug-specific variables. After a selection process, a score for risk estimation was constructed. The 80+ score was internally validated, and the discriminatory ability of the score and of STOPP, START and MAI was assessed using C-statistics. Results: Seven variables were selected. Impaired renal function, pulmonary disease, malignant disease, living in a nursing home, being prescribed an opioid or being prescribed a drug for peptic ulcer or gastroesophageal reflux disease were associated with an increased risk, while being prescribed an antidepressant drug (tricyclic antidepressants not included) was linked to a lower risk of the outcome. These variables made up the components of the 80+ score. The C-statistics were 0.71 (80+), 0.57 (STOPP), 0.54 (START) and 0.63 (MAI). Conclusions: We developed and internally validated a score for prediction of risk of rehospitalisation and mortality in hospitalised older people. The score discriminated risk better than available tools for inappropriate prescribing. Pending external validation, this score can aid in clinical identification of high-risk patients and targeting of interventions.
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| 10. |
- Alassaad, Anna, 1977-, et al.
(författare)
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A tool for prediction of risk of rehospitalization and mortality in hospitalized elderly
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Older patients with multiple co-morbidities and multi-drug use are at high risk of revisits to hospital and mortality, which poses an increasing health economic burden.Objective: To construct and internally validate a risk score, the “80+ score”, for revisits to hospital and mortality for older patients, incorporating aspects of pharmacotherapy. Our secondary aim was to compare the discriminatory ability of the score with that of three validated tools for measuring inappropriate prescribing: Screening Tool of Older Person’s Prescriptions (STOPP), Screening Tool to Alert doctors to Right Treatment (START) and Medication Appropriateness Index (MAI).Design: Secondary use of data from a randomized controlled trial investigating effects of a comprehensive pharmacist intervention, conducted in 2005-2006.Setting: Two acute internal medicine wards at Uppsala University hospital.Participants: Data from 368 patients, 80 years and older, admitted to one of the study wards.Main outcomes and measures: Time to rehospitalization or death during the year after discharge from hospital. Candidate variables were selected among a large number of clinical and drug-specific variables. After a selection process, a score for risk-estimation was constructed. The score was internally validated, and the discriminatory ability of the new score and of STOPP, START and MAI was assessed using C-statistics. Results: Seven variables were selected for the 80+ score. Impaired renal function, pulmonary disease (chronic obstructive pulmonary disease [COPD or asthma]), malignant disease (past or present), living in nursing home, being prescribed an opioid or being prescribed a drug for peptic ulcer or gastroesophageal reflux disease was associated with an increased risk, while being prescribed an antidepressant drug (tricyclic antidepressants not included) was linked to a lower risk of the outcome. These variables made up the components of the 80+ score. The C-statistics were 0.71 (80+ score), 0.57 (STOPP), 0.54 (START) and 0.63 (MAI). Conclusion and Relevance: We developed and internally validated a score for prediction of risk of rehospitalization and mortality in hospitalized older people. The score discriminated risk considerably better than available tools for inappropriate prescribing. Pending external validation, this score can aid in clinical identification of high-risk patients and targeting of interventions.
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