| 1. |
- Abdo, A. A., et al.
(author)
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The second Fermi large area telescope catalog of gamma-ray pulsars
- 2013
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In: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 208:2, s. 17-
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Journal article (peer-reviewed)abstract
- This catalog summarizes 117 high-confidence ≥0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.
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| 2. |
- Di Nuzzo, Daniele, et al.
(author)
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Evidence for space-charge-limited conduction in organic photovoltaic cells at open-circuit conditions
- 2013
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In: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 87:8
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Journal article (peer-reviewed)abstract
- The ac admittance of solar cells under illumination is investigated under open-circuit conditions. Open-circuit conditions are imposed by inserting a probe capacitor into the circuit. The capacitance and conductance of the cells are investigated as function of frequency and continuous illumination intensity. Results are compared with numerical and analytical modeling of charge recombination and transport. In bulk heterojunction solar cells with [6,6]-Phenyl-C-61(C-71)-butyric acid methyl ester as acceptor and poly(3-hexylthiophene) or poly[2-methoxy-5-(2-ethylhexyloxy)-p-phenylene vinylene] as electron donor, the high-frequency capacitance C and conductance G follow a power-law dependence on intensity of white light I, with G(I) proportional to I-3/4 and C(I) proportional to I-1/4. The modeling shows that these dependencies can be explained in terms of space-charge-limited current in combination with Langevin type recombination of carriers. For poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b]dithiophene-2,6-diyl]] the capacitance shows a weaker dependence on intensity, indicating fast recombination of photogenerated carriers. Results indicate that the fill factor of relatively well performing polymer solar cells can still be limited by space charge effects and can be improved by enhancing the charge carrier mobility or by reducing the bimolecular Langevin recombination. DOI: 10.1103/PhysRevB.87.085207
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| 3. |
- Hein, Tobias, 1982, et al.
(author)
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Prospective analysis of intrinsic and extrinsic risk factors on the development of Achilles tendon pain in runners
- 2014
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In: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 24:3
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Journal article (peer-reviewed)abstract
- There are currently no generally accepted, consistent results that clearly characterize factors causing Achilles tendon pain (AT) in runners. Therefore, we carried out a prospective study to evaluate the multifactorial influence of clinical, biomechanical (isometric strength measurements and three-dimensional kinematics) and training-related risk factors on the development of AT. Two hundred sixty-nine uninjured runners were recruited and underwent an initial examination. One hundred forty-two subjects completed their participation by submitting training information on a weekly basis over a maximal period of 1 year. Forty-five subjects developed an overuse injury, with 10 runners suffering from AT. In an uninjured state, AT runners already demonstrated decreased knee flexor strength and abnormal lower leg kinematics (sagittal knee and ankle joint) compared with a matched control group. A relationship between years of running experience or previous overuse injuries and the development of new symptoms could not be established. The interrelationship of biomechanical and training-specific variables on the generation of AT is evident. A combination of alterations in lower leg kinematics and higher impacts caused by fast training sessions might lead to excessive stress on the Achilles tendon during weight bearing and thus to AT in recreational runners.
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| 6. |
- Steinhilber, B., et al.
(author)
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Stiffness, Pain, and Hip Muscle Strength Are Factors Associated With Self-reported Physical Disability in Hip Osteoarthritis
- 2014
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In: Journal of Geriatric Physical Therapy. - 1539-8412. ; 37:3, s. 99-105
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Journal article (peer-reviewed)abstract
- Background: Physical disability (PD) is common among patients with osteoarthritis (OA) of the hip. Exercise therapy is proposed to be a potential intervention to reduce PD. However, the optimal targets of an exercise program are not known. Purpose: The aim of the present study was to identify factors that explain the level of self-reported PD in patients with hip OA. Knowledge of these factors will help develop specific and effective exercise programs. Methods: Data from 149 patients with hip OA (85 men and 64 women) were analyzed. Self-reported PD was quantified using the physical function subscale of the Western Ontario and McMaster index. A stepwise regression analysis was conducted to identify significant factors associated with self-reported PD. Results: Stiffness, pain, and hip muscle strength were found to be significant factors related to the level of self-reported PD in hip OA. These factors explained 59% (r(2) adjusted = 0.59) of the variance. Body mass index, gender, age, and passive internal hip rotation and flexion range of motion explained only minor parts of the dependent variable self-reported PD. Discussion and Conclusion: Stiffness, pain, and hip muscle strength are associated with self-reported PD in hip OA. It is imperative that exercise treatments for hip OA include strategies to modify these factors. Further research should evaluate their role in preventing hip OA.
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| 7. |
- Stenfelt, Stefan, 1969-, et al.
(author)
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e-Health technologies for adult hearing screening
- 2011
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In: Audiology Research. - : PAGEPress. - 2039-4349. ; 1, s. 55-57
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Journal article (peer-reviewed)abstract
- The development of hearing diagnosis methods and hearing screeningmethods are not isolated phenomena: they are intimately relatedto changes in the cultural background and to advances in fields of medicineand engineering. In the recent years, there has been a rapid evolutionin the development of fast, easy and reliable techniques for lowcosthearing screening initiatives. Since adults and elderly people typicallyexperience a reduced hearing ability in challenging listening situations[e.g., in background noise, in reverberation, or with competingspeech (Pichora‑Fuller & Souza, 2003)], these newly developedscreening tests mainly rely on the recognition of speech stimuli innoise, so that the real experienced listening difficulties can be effectivelytargeted (Killion & Niquette, 2000). New tests based on therecognition of speech in noise are being developed on portable, battery-operated devices (see, for example, Paglialonga et al., 2011), ordistributed diffusely using information and communication technologies.The evolutions of e-Health and telemedicine have shifted focusfrom patients coming to the hearing clinic for hearing health evaluationtowards the possibility of evaluating the hearing status remotelyat home. So far, two ways of distributing the hearing test have primarilybeen used: ordinary telephone networks (excluding mobile networks)and the internet. When using the telephone network for hearingscreening, the predominantly test is a speech-in-noise test oftenreferred to as the digit triplet test where the subjects hearing status isevaluated as the speech-to-noise threshold for spoken digits. This testis today available in some ten countries in Europe, North America andAustralia. The use of internet as testing platform allows several differenttypes of hearing assessment tests such as questionnaires, differenttypes of speech in noise tests, temporal gap detection, sound localization(minimum audible angle), and spectral (un)masking tests.Also, the use of the internet allows audiovisual presentations as wellas visual interaction and cues in the tests for a more ecologicalapproach. Even if several new and novel approaches for hearingassessment using the internet are surfacing, the validated tests arebased on questionnaires or speech-in-noise. Although the internetallows for a broader flora of pure auditory and audiovisual tests forhearing health assessment, calibration problems such as timinguncertainty, output levels and modes of presentation (speakers or earphones)limits the usability at present.
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| 9. |
- Thodi, Chryssola, et al.
(author)
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Adult Hearing Screening : Follow-Up and Outcomes
- 2013
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In: American Journal of Audiology. - : American Speech-Language-Hearing Association. - 1059-0889 .- 1558-9137. ; 22, s. 183-185
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Journal article (peer-reviewed)abstract
- PURPOSE:To screen hearing and evaluate outcomes in community-dwelling older adults.METHOD:Three thousand and twenty-five adults responded to an invitation to be screened by questionnaire, otoscopy, and pure-tone audiometry. Pure-tone average (PTA) >35 dB HL in the worse ear, unilateral hearing loss, or otoscopic findings were the criteria for referral for services. A questionnaire related to compliance with referral recommendations was completed by telephone interview for 160 randomly selected participants after 1-2 years from referral.RESULTS:The referral rate for audiologic/hearing aid evaluation was 46%, and referral for cerumen removal/medical evaluation was 17%. Of the people referred for audiologic/hearing aid evaluation, 18% tried a hearing aid; 2 years later, 11% were using a hearing aid. Screening recommendations affected participants' decision to seek help. Study participants stated that the screening was helpful, it should be offered to everybody, and they would participate in future screenings.CONCLUSION:Although adult hearing screening offered timely identification of hearing loss for adults seeking help, follow-up with hearing aid treatment was low.
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| 10. |
- Thodi, Chryssola, et al.
(author)
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Adult hearing screening: the Cyprus Pilot Program
- 2011
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In: Audiology Research. - : PAGEPress. - 2039-4349. ; 1, s. 69-70
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Journal article (peer-reviewed)abstract
- Hearing loss is the third most common condition affecting adults over 65 (Cruickshanks et al., 1998). It can affect quality of life, limiting the ability to communicate efficiently, and leading to isolation, psychological strain, and functional decline (LaForge, Spector, Sternberg, 1992; Yueh, Shapiro, MacLean, Shekelle, 2003). Communication limitations impinge on the person directly, as well as the family, friends, and social circle. Reports on hearing loss among adults indicate that less than 25% of people who can benefit from amplification are actually using hearing aids, and that people diagnosed with a hearing loss delay seeking amplification by about seven years (Kochkin, 1997). Often, family members are the driving force behind a person with a hearing loss who decides to seek help. Adult hearing screening programs might have a positive effect on raising public awareness on hearing loss and its implications, and shortening delay time for intervention. There is no routine hearing screening for the adult population in Cyprus. The health system provides hearing tests for beneficiaries upon physician recommendation or self-referral. The Cyprus pilot adult hearing screening program (ΑΠΑΣ- EVERYONE- Greek acronym for Screening- Intervention-Hearing-Participation to Life) screened hearing in retired adults.
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| 11. |
- van der Hofstad, Tom G. J., et al.
(author)
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Carrier Recombination in Polymer Fullerene Solar Cells Probed by Reversible Exchange of Charge between the Active Layer and Electrodes Induced by a Linearly Varying Voltage
- 2013
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In: The Journal of Physical Chemistry C. - : American Chemical Society. - 1932-7447 .- 1932-7455. ; 117:7, s. 3210-3220
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Journal article (peer-reviewed)abstract
- The use of a voltage pulse that varies linearly with time and that is symmetric in time around t = 0 allows for simultaneous determination of (photo)capacitance and (photo)conductance of polymer solar cells. From the measured capacitance, an average density of reversibly extractable carriers is determined, and the result is compared to numerical drift-diffusion simulations. Results are in agreement with large charge densities near the contacts that can be exchanged with the electrode in a thermodynamically reversible manner upon changing the voltage. The combined determination of capacitance and conductance yields a relaxation time tau(rel) for photogenerated charge carriers. Results on thermally annealed poly(3-hexylthiopene):fullerene bulk heterojunction solar cells indicate tau(rel) similar to 2 mu s, limited by extraction and not significantly affected by bimolecular recombination under intensities up to 1 sun. In contrast, for small bandgap poly(diketopyrrolopyrrole-alt-quinquethiophene)-fullerene solar cells with similar to 5% power conversion efficiency, tau(rel) is limited by bimolecular recombination. This illustrates the need for very fast charge transport rates to avoid losses due to bimolecular recombination in solar cells with high charge generation rates. Conclusions from the charge exchange experiments are confirmed by time domain measurements using pulsed illumination.
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