36 research outputs found
An Exploratory Survey of Self-Reported Joint Pain Among College Students
Topics in Exercise Science and Kinesiology Volume 4: Issue 1, Article 13, 2023. Prior research has shown that college students are a unique subset of our global population that commonly experience stresses and strains to their musculoskeletal system as they complete their traditional coursework. Most of this population is viewed as healthy since their joints and skeletal systems have yet to be subjected to the levels of wear and tear of their elder constituents. However, there are still individuals within this population that often report experiencing some level of joint pain or discomfort that would not fall underneath the classic diagnoses of arthritis or other severe joint-related pathologies. The purpose of this descriptive study was to examine joint pain in non-clinical college students and some of the potential contributions to that pain. An email was sent to the entire current student population at a southeastern university in the United States inviting them to complete an online questionnaire about joint pain. Prior to its distribution, a pilot version of the questionnaire was distributed and tested to ensure readability and to establish content validity. The final version of the questionnaire was distributed twice during the fall 2021 semester. From the total number of students who may have received the email invitation (n = 18,985), 211 students completed the survey for a response rate of 1.11%. Of the 116 respondents who had never seen a healthcare professional for a joint injury or joint surgery, 72 reported current joint pain (62%). Thirty participants (47.6%) reported that the duration of their pain has lasted longer than three months. Participants reported cervical pain (76%), lumbar spine pain (84.8%), knee pain (65.1%), and hip or pelvis pain (76.2%) as the most frequent joints being affected. While typically considered healthy, college students are experiencing joint health-related pain and discomfort. Due to lack of past and current research on joint health in college students, the results of this exploratory study may begin to shed light on the need to implement and fund more proactive methods to best address this emerging issue
Limitations on the principle of stationary phase when it is applied to tunneling analysis
Using a recently developed procedure - multiple wave packet decomposition -
here we study the phase time formulation for tunneling/reflecting particles
colliding with a potential barrier. To partially overcome the analytical
difficulties which frequently arise when the stationary phase method is
employed for deriving phase (tunneling) time expressions, we present a
theoretical exercise involving a symmetrical collision between two identical
wave packets and an one-dimensional rectangular potential barrier. Summing the
amplitudes of the reflected and transmitted waves - using a method we call
multiple peak decomposition - is shown to allow reconstruction of the scattered
wave packets in a way which allows the stationary phase principle to be
recovered.Comment: 17 pages, 2 figure
Multi-proxy inferred hydroclimatic conditions at Bęczkowice fen (central Poland); the influence of fluvial processes and human activity in the stone age
Fens have been forming in the river valleys of central Poland since the Bølling and went through a transformation from fully aquatic to semiterrestrial habitats during the Younger Dryas/Holocene transition. This drove plant and invertebrate communities and left a distinct pattern in chemical sediment composition, which is why river valley peatlands are sensitive palaeo-archives of climatic, hydrological and edaphic changes. Here we reconstruct the Late Weichselian history of the Bęczkowice fen in the upper Luciąża River valley using geochemical, pollen, Cladocera and Chironomidae proxies. Pollen-based age estimation indicates that the analysed peat sequence dates from the Bølling to Early Holocene. The layers 190-170 cm and 125-105 cm of the studied core were reworked by fluvial processes. Chironomidae and Cladocera communities indicate mostly limnetic conditions during the Allerød and early Younger Dryas. Peatland pools were supplied mostly by Luciąża River floods, but also by groundwater. Since the onset of the Holocene, the water level has dropped, eliminating aquatic midges and water fleas, and supporting taxa typical of astatic waters and wet soil.Peer reviewe
The stationary phase condition applicability to the study of tunnel effect
Some recent theoretical studies have tended to employ analytically-continuous
{\em gaussian}, or infinite-bandwidth step pulses to examine tunneling process.
The stationary phase method is often employed to this aim. However, {\em
gaussian} functions do not have a well-defined front, such that their speed of
propagation becomes ambiguous. Also, infinite bandwidth signals cannot
propagate through any real physical medium (whose transfer function is
therefore finite) without pulse distortion, which also leads to ambiguities in
determining propagation velocity during the tunneling process. In this
manuscript, we appoint some incompatibilities with the application of the
method of stationary phase in deriving tunneling times which, eventually, can
ruin the {\em superluminal} interpretation of transition times.Comment: 6 pages, 1 figur
On Superluminal motions in photon and particle tunnelings
It is shown that the Hartman-Fletcher effect is valid for all the known
expressions of the mean tunnelling time, in various nonrelativistic approaches,
for the case of finite width barriers without absorption. Then, we show that
the same effect is not valid for the tunnelling time mean-square fluctuations.
On the basis of the Hartman-Fletcher effect and the known analogy between
photon and nonrelativistic-particle tunnelling, one can explain the
Superluminal group-velocities observed in various photon tunnelling experiments
(without violation of the so-called "Einstein causality").Comment: standard LaTeX file; accepted for publication in Phys. Lett.
Measurement of Superluminal optical tunneling times in double-barrier photonic bandgaps
Tunneling of optical pulses at 1.5 micron wavelength through double-barrier
periodic fiber Bragg gratings is experimentally investigated. Tunneling time
measurements as a function of barrier distance show that, far from the
resonances of the structure, the transit time is paradoxically short, implying
Superluminal propagation, and almost independent of the distance between the
barriers. These results are in agreement with theoretical predictions based on
phase time analysis and also provide an experimental evidence, in the optical
context, of the analogous phenomenon expected in Quantum Mechanics for
non-resonant superluminal tunneling of particles across two successive
potential barriers. [Attention is called, in particular, to our last Figure].
PACS nos.: 42.50.Wm, 03.65.Xp, 42.70.Qs, 03.50.De, 03.65.-w, 73.40.GkComment: LaTeX file (8 pages), plus 5 figure
The Exact Correspondence between Phase Times and Dwell Times in a Symmetrical Quantum Tunneling Configuration
The general and explicit relation between the phase time and the dwell time
for quantum tunneling or scattering is investigated. Considering a symmetrical
collision of two identical wave packets with an one-dimensional barrier, here
we demonstrate that these two distinct transit time definitions give connected
results where, however, the phase time (group delay) accurately describes the
exact position of the scattered particles. The analytical difficulties that
arise when the stationary phase method is employed for obtaining phase
(traversal) times are all overcome. Multiple wave packet decomposition allows
us to recover the exact position of the reflected and transmitted waves in
terms of the phase time, which, in addition to the exact relation between the
phase time and the dwell time, leads to right interpretation for both of them.Comment: 11 pages, 2 figure
Small Corrections to the Tunneling Phase Time Formulation
After reexamining the above barrier diffusion problem where we notice that
the wave packet collision implies the existence of {\em multiple} reflected and
transmitted wave packets, we analyze the way of obtaining phase times for
tunneling/reflecting particles in a particular colliding configuration where
the idea of multiple peak decomposition is recovered. To partially overcome the
analytical incongruities which frequently rise up when the stationary phase
method is adopted for computing the (tunneling) phase time expressions, we
present a theoretical exercise involving a symmetrical collision between two
identical wave packets and a unidimensional squared potential barrier where the
scattered wave packets can be recomposed by summing the amplitudes of
simultaneously reflected and transmitted wave components so that the conditions
for applying the stationary phase principle are totally recovered. Lessons
concerning the use of the stationary phase method are drawn.Comment: 14 pages, 3 figure
Frequency of Chlamydia trachomatis in Ureaplasma-positive healthy women attending their first prenatal visit in a community hospital in Sapporo, Japan
<p>Abstract</p> <p>Background</p> <p>Although <it>Chlamydia trachomatis </it>is the most commonly reported pathogen that causes urogenital infection such as urethritis or cervicitis, <it>Ureaplasma parvum </it>and <it>Ureaplasma urealyticum</it>, which are commensals in the genital tract, have also now been recognized as contributors to urogenital infection. However, whether the presence of either <it>U. parvum </it>or <it>U. urealyticum </it>is related to that of <it>C. trachomatis </it>in the urogenital tract remains unknown. We therefore attempted to estimate by PCR the prevalence of <it>C. trachomatis, U. parvum </it>and <it>U. urealyticum </it>in endocervical samples obtained from healthy women attending their first prenatal visit in Sapporo, Japan.</p> <p>Methods</p> <p>The samples were taken from 303 apparently healthy women, and the extracted DNAs (<it>n </it>= 280) were used for PCR detection targeting <it>C. trachomatis, U. parvum </it>and <it>U. urealyticum</it>. Statistical analysis of the data was performed by Fisher's exact test.</p> <p>Results</p> <p>PCR detection revealed that the prevalence of <it>C. trachomatis, U. parvum </it>and <it>U. urealyticum </it>was 14.3% (40/280), 41.7% (117/280) and 8.9% (25/280), respectively. <it>C. trachomatis ompA </it>genotype D was most frequently identified. Surprisingly, either <it>C. trachomatis </it>or <it>Ureaplasma </it>spp. was detected in almost half of the healthy women. Mixed infection of <it>C. trachomatis </it>with either <it>U. parvum </it>or <it>U. urealyticum </it>was also observed in 9.2% (26/280) of the women. There was a significant association between <it>C. trachomatis </it>and either <it>U. parvum </it>(<it>p </it>= 0.023) or <it>Ureaplasma </it>total (<it>p </it>= 0.013), but not <it>U. urealyticum </it>(<it>p </it>= 0.275).</p> <p>Conclusion</p> <p>This study demonstrated that the presence of <it>Ureaplasma </it>had a significant effect on the presence of <it>C. trachomatis </it>in the genital tract of healthy women, suggesting that mixed infection is an important factor in bacterial pathogenesis in the genital tract.</p