251 research outputs found
The Effects of Centering Prayer on Well-Being in a Sample of Undergraduate Students: A Pilot Study
Contemplative practices have likely been used for self-awareness, concentration, creativity, and well-being since the dawn of time. While practices such as yoga and Buddhist meditation have been extensively studied in recent decades, Christian contemplative practices have received less attention in empirical research. This study aims to investigate the effects of centering prayer, a Christian contemplative practice, on mental health and well-being. The research focuses on college students enrolled in a religious studies course that incorporates centering prayer into the curriculum. It is a pilot study because it is the first to explore centering prayer in an undergraduate setting. Using a comparison group from another religious studies course, the study examines whether practicing centering prayer regularly for seven weeks can lead to changes in anxiety, stress, depression, mindfulness, satisfaction with life, hope, and compassion as assessed by multiple questionnaires. Additionally, the study explores whether religiosity influences the impact of centering prayer on these variables. Participants were recruited through their course enrollment, and data was collected through online surveys administered at three time points during the study. Multivariate analyses of covariance indicated trends suggesting that centering prayer may contribute to decreased anxiety and increased hope and compassion. However, no significant changes in these outcomes were observed (pâ\u3eâ.05). The study highlights the potential therapeutic benefits of centering prayer and the need for further research on Christian contemplative practices
Assessment of the Calibration of Periodontal Diagnosis and Treatment Planning Among Dental Students at Three Dental Schools
Calibration in diagnosis and treatment planning is difficult to achieve due to variations that exist in clinical interpretation. To determine if dental faculty members are consistent in teaching how to diagnose and treat periodontal disease, variations among dental students can be evaluated. A previous study reported high variability in diagnoses and treatment plans of periodontal cases at Indiana University School of Dentistry. This study aimed to build on that one by extending the research to two additional schools: Marquette University School of Dentistry and West Virginia University School of Dentistry. Diagnosis and treatment planning by 40 third- and fourth-year dental students were assessed at each of the schools. Students were asked to select the diagnosis and treatment plans on a questionnaire pertaining to 11 cases. Their responses were compared using chi-square tests, and multirater kappa statistics were used to assess agreement between classes and between schools. Logistic regression models were used to evaluate the effects of school, class year, prior experience, and GPA/class rank on correct responses. One case had a statistically significant difference in responses between third- and fourth-year dental students. Kappas for school agreement and class agreement were low. The students from Indiana University had higher diagnosis and treatment agreements than the Marquette University students, and the Marquette students fared better than the West Virginia University students. This study can help restructure future periodontal courses for a better understanding of periodontal diagnosis and treatment planning
Parametric amplification of magnetoplasmons in semiconductor quantum dots
We show that the magnetoplasmon collective modes in quasi-two-dimensional
semiconductor quantum dots can be parametrically amplified by periodically
modulating the magnetic field perpendicular to the nanostructure. The two
magnetoplasmon modes are excited and amplified simultaneously, leading to an
exponential growth of the number of bosonic excitations in the system. We
further demonstrate that damping mechanisms as well as anharmonicities in the
confinement of the quantum dot lead to a saturation of the parametric
amplification. This work constitutes a first step towards parametric
amplification of collective modes in many-body fermionic systems beyond one
dimension.Comment: 12 pages, 5 figures; published versio
The Asiago-ESO/RASS QSO Survey II. The Southern Sample
This is the second paper of a series describing the Asiago-ESO/RASS QSO survey, a project aimed at the construction of an all-sky statistically well-defined sample of very bright QSOs (B_J 30^{\circ}). The area covered by the survey is 5660 sq. deg. Spectroscopy for the 137 still unidentified objects has been obtained. The total number of AGN turns out to be 111, 63 of which are new identifications. The properties of the selection are discussed. The completeness and the success rate for this survey at the final stage are 63% and 46%, respectively
Spin-pairing instabilities at the coincidence of two Landau levels
The effect of interactions near the coincidence of two Landau levels with
opposite spins at filling factor 1/2 is investigated. By mapping to Composite
Fermions it is shown that the fluctuations of the gauge field induces an
effective attractive Fermion interaction. This can lead to a spin-singlet
ground state that is separated from the excited states by a gap. The magnitude
of the gap is evaluated. The results are consistent with the recently observed
half-polarized states in the FQHE at a fixed filling factor. It is suggested
that similar anomalies exist for other spin configurations in degenerate
spin-up and spin-down Landau levels. An experiment for testing the spin-singlet
state is proposed.Comment: to be published in Physical Review
Implantable Medical Devices; Networking Security Survey
Abstract The industry of implantable medical devices (IMDs) is constantly evolving, which is dictated by the pressing need to comprehensively address new challenges in the healthcare field. Accordingly, IMDs are becoming more and more sophisticated. Not long ago, the range of IMDs' technical capacities was expanded, making it possible to establish Internet connection in case of necessity and/or emergency situation for the patient. At the same time, while the web connectivity of today's implantable devices is rather advanced, the issue of equipping the IMDs with sufficiently strong security system remains unresolved. In fact, IMDs have relatively weak security mechanisms which render them vulnerable to cyber-attacks that compromise the quality of IMDs' functionalities. This study revolves around the security deficiencies inherent to three types of sensor-based medical devices; biosensors, insulin pump systems and implantable cardioverter defibrillators. Manufacturers of these devices should take into consideration that security and effectiveness of the functionality of implants is highly dependent on the design. In this paper, we present a comprehensive study of IMDs' architecture and specifically investigate their vulnerabilities at networking interface
Photosensitization of pancreatic cancer cells by cationic alkyl-porphyrins in free form or engrafted into POPC liposomes: The relationship between delivery mode and mechanism of cell death
Cationic porphyrins bearing an alkyl side chain of 14 (2b) or 18 (2d) carbons dramatically inhibit proliferation of pancreatic cancer cells following treatment with light. We have compared two different ways of delivering porphyrin 2d: either in free form or engrafted into palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes (L-2d). Cell cytometry shows that while free 2d is taken up by pancreatic cancer cells by active (endocytosis) and passive (membrane fusion) transports, L-2d is internalized solely by endocytosis. Confocal microscopy showed that free 2d co-localizes with the cell membrane and lysosomes, whereas L-2d partly co-localizes with lysosomes and ER. It is found that free 2d inhibits the KRAS-Nrf2-GPX4 axis and strongly triggers lipid peroxidation, resulting in cell death by ferroptosis. By contrast, L-2d does not affect the KRAS-Nrf2-GPX4 axis and activates cell death mainly through apoptosis. Overall, our study demonstrates for the first time that cationic alkyl porphyrins, which have a IC50 ~ 23 nM, activate a dual mechanism of cell death, ferroptosis and apoptosis, where the predominant form depends on the delivery mode
The Asiago-ESO/RASS QSO Survey. III. Clustering analysis and its theoretical interpretation
This is the third paper of a series describing the Asiago-ESO/RASS QSO survey
(AERQS), a project aimed at the construction of an all-sky statistically
well-defined sample of relatively bright QSOs (B<15) at z<0.3. We present here
the clustering analysis of the full spectroscopically identified database (392
AGN). The clustering signal at 0.02<z<0.22 is detected at a 3-4 sigma level and
its amplitude is measured to be r_0=8.6\pm 2.0 h^{-1} Mpc (in a LambdaCDM
model). The comparison with other classes of objects shows that low-redshift
QSOs are clustered in a similar way to Radio Galaxies, EROs and early-type
galaxies in general, although with a marginally smaller amplitude. The
comparison with recent results from the 2QZ shows that the correlation function
of QSOs is constant in redshift or marginally increasing toward low redshift.
We discuss this behavior with physically motivated models, deriving interesting
constraints on the typical mass of the dark matter halos hosting QSOs, M_DMH=
10^{12.7} h^{-1} M_sun (10^{12.0}-10^{13.5}h^{-1} M_sun at 1 sigma confidence
level). Finally, we use the clustering data to infer the physical properties of
local AGN, obtaining M_BH=2 10^8 h^{-1} M_sun (10^7-3 10^9 h^{-1} M_sun) for
the mass of the active black holes, tau_{AGN}= 8 10^6 yr (2 10^{6}-5 10^{7} yr)
for their life-time and eta = 0.14 for their efficiency (always for a LambdaCDM
model).Comment: 37 pages, Astronomical Journal in press. Changes to match the referee
comment
The OGLE View of Microlensing towards the Magellanic Clouds. II. OGLE-II SMC data
The primary goal of this paper is to provide the evidence that can either
prove or falsify the hypothesis that dark matter in the Galactic halo can clump
into stellar-mass compact objects. If such objects existed, they would act as
lenses to external sources in the Magellanic Clouds, giving rise to an
observable effect of microlensing. We present the results of our search for
such events, based on the data from the second phase of the OGLE survey
(1996-2000) towards the SMC. The data set we used is comprised of 2.1 million
monitored sources distributed over an area of 2.4 square degrees. We found only
one microlensing event candidate, however its poor quality light curve limited
our discussion on the exact distance to the lensing object.
Given a single event, taking the blending (crowding of stars) into account
for the detection efficiency simulations, and deriving the HST-corrected number
of monitored stars, the microlensing optical depth is tau=(1.55+-1.55)10e-7.
This result is consistent with the expected SMC self-lensing signal, with no
need of introducing dark matter microlenses. Rejecting the unconvincing event
leads to the upper limit on the fraction of dark matter in the form of MACHOs
to f<20 per cent for deflectors' masses around 0.4 Msun and f<11 per cent for
masses between 0.003 and 0.2 Msun (95 per cent confidence limit). Our result
indicates that the Milky Way's dark matter is unlikely to be clumpy and form
compact objects in the sub-solar-mass range.Comment: Accepted for publication in MNRAS. Data in electronic form are
available on the OGLE's website: http://ogle.astrouw.edu.pl
Elliptic and hyperelliptic magnetohydrodynamic equilibria
The present study is a continuation of a previous one on "hyperelliptic"
axisymmetric equilibria started in [Tasso and Throumoulopoulos, Phys. Plasmas
5, 2378 (1998)].
Specifically, some equilibria with incompressible flow nonaligned with the
magnetic field and restricted by appropriate side conditions like "isothermal"
magnetic surfaces, "isodynamicity" or P + B^2/2 constant on magnetic surfaces
are found to be reducible to elliptic integrals. The third class recovers
recent equilibria found in [Schief, Phys. Plasmas 10, 2677 (2003)]. In contrast
to field aligned flows, all solutions found here have nonzero toroidal magnetic
field on and elliptic surfaces near the magnetic axis.Comment: 9 page
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