2,712 research outputs found
Changes in women’s facial skin color over the ovulatory cycle are not detectable by the human visual system
Human ovulation is not advertised, as it is in several primate species, by conspicuous sexual swellings. However, there is increasing evidence that the attractiveness of women’s body odor, voice, and facial appearance peak during the fertile phase of their ovulatory cycle. Cycle effects on facial attractiveness may be underpinned by changes in facial skin color, but it is not clear if skin color varies cyclically in humans or if any changes are detectable. To test these questions we photographed women daily for at least one cycle. Changes in facial skin redness and luminance were then quantified by mapping the digital images to human long, medium, and shortwave visual receptors. We find cyclic variation in skin redness, but not luminance. Redness decreases rapidly after menstrual onset, increases in the days before ovulation, and remains high through the luteal phase. However, we also show that this variation is unlikely to be detectable by the human visual system. We conclude that changes in skin color are not responsible for the effects of the ovulatory cycle on women’s attractiveness
Experimental study of beam distortion due to fiducial markers during salvage HIFU in the prostate
BACKGROUND: Prostate cancer is frequently treated using external beam radiation therapy (EBRT). Prior to therapy, the prostate is commonly implanted with a small number of permanent fiducial markers used to monitor the position of the prostate during therapy. In the case of local cancer recurrence, high-intensity focused ultrasound (HIFU) provides a non-invasive salvage treatment option. However, the impact of the fiducial markers on HIFU treatment has not been thoroughly studied to date. The objective of this study was to experimentally investigate the effect of a single EBRT fiducial marker on the efficacy of HIFU treatment delivery using a tissue-mimicking material (TMM).
METHODS: A TMM with the acoustic properties of the prostate was developed based on a polyacrylamide hydrogel containing bovine serum albumin. Each phantom was implanted with a cylindrical fiducial marker and then sonicated using a 3.3 MHz focused bowl HIFU transducer. Two sets of experiments were performed. In the first, a single lesion was created at different positions along either the anteroposterior or left-right axes relative to the marker. In the second, a larger ablation volume was created by raster scanning. The size and position of the ablated volume were assessed using a millimetre grid overlaid on the phantom.
RESULTS: The impact of the marker on the position and size of the HIFU lesion was significant when the transducer focus was positioned within 7 mm anteriorly, 18 mm posteriorly or within 3 mm laterally of the marker. Beyond this, the generated lesion was not affected. When the focus was anterior to the marker, the lesion increased in size due to reflections. When the focus was posterior, the lesion decreased in size or was not present due to shadowing.
CONCLUSIONS: The presence of an EBRT fiducial marker may result in an undertreated region beyond the marker due to reduced energy arriving at the focus, and an overtreated region in front of the marker due to reflections. Depending on the position of the targeted regions and the distribution of the markers, both effects may be undesirable and reduce treatment efficacy. Further work is necessary to investigate whether these results indicate the necessity to reconsider patient selection and treatment planning for prostate salvage HIFU after failed EBRT
Geometrical effects and signal delay in time-dependent transport at the nanoscale
The nonstationary and steady-state transport through a mesoscopic sample
connected to particle reservoirs via time-dependent barriers is investigated
within the reduced density operator method. The generalized Master equation is
solved via the Crank-Nicolson algorithm by taking into account the memory
kernel which embodies the non-Markovian effects that are commonly disregarded.
We propose a physically reasonable model for the lead-sample coupling which
takes into account the match between the energy of the incident electrons and
the levels of the isolated sample, as well as their overlap at the contacts.
Using a tight-binding description of the system we investigate the effects
induced in the transient current by the spectral structure of the sample and by
the localization properties of its eigenfunctions. In strong magnetic fields
the transient currents propagate along edge states. The behavior of populations
and coherences is discussed, as well as their connection to the tunneling
processes that are relevant for transport.Comment: 26 pages, 13 figures. To appear in New Journal of Physic
Evaluation of a Command-line Parser-based Order Entry Pathway for the Department of Veterans Affairs Electronic Patient Record
Objective: To improve and simplify electronic order entry in an existing electronic patient record, the authors developed an alternative system for entering orders, which is based on a command- interface using robust and simple natural-language techniques. Design: The authors conducted a randomized evaluation of the new entry pathway, measuring time to complete a standard set of orders, and users' satisfaction measured by questionnaire. A group of 16 physician volunteers from the staff of the Department of Veterans Affairs Puget Sound Health Care System-Seattle Division participated in the evaluation. Results: Thirteen of the 16 physicians (81%) were able to enter medical orders more quickly using the natural-language-based entry system than the standard graphical user interface that uses menus and dialogs (mean time spared, 16.06 ± 4.52 minutes; P=0.029). Compared with the graphical user interface, the command--based pathway was perceived as easier to learn (P<0.01), was considered easier to use and faster (P<0.01), and was rated better overall (P<0.05). Conclusion: Physicians found the command- interface easier to learn and faster to use than the usual menu-driven system. The major advantage of the system is that it combines an intuitive graphical user interface with the power and speed of a natural-language analyze
Topographic controls on post-Oligocene changes in ice-sheet dynamics, Prydz Bay region, East Antarctica
Optical properties of the vibrations in charged C molecules
The transition strengths for the four infrared-active vibrations of charged
C molecules are evaluated in self-consistent density functional theory
using the local density approximation. The oscillator strengths for the second
and fourth modes are strongly enhanced relative to the neutral C
molecule, in good agreement with the experimental observation of ``giant
resonances'' for those two modes. Previous theory, based on a ``charged
phonon'' model, predicted a quadratic dependence of the oscillator strength on
doping, but this is not borne out in our calculations.Comment: 10 pages, RevTeX3.
How do people with diabetes describe their experiences in primary care? Evidence from 85,760 patients with self-reported diabetes from the English General Practice Patient Survey.
OBJECTIVE: Developing primary care is an important current health policy goal in the U.S. and England. Information on patients' experience can help to improve the care of people with diabetes. We describe the experiences of people with diabetes in primary care and examine how these experiences vary with increasing comorbidity. RESEARCH DESIGN AND METHODS: Using data from 906,578 responders to the 2012 General Practice Patient Survey (England), including 85,760 with self-reported diabetes, we used logistic regressions controlling for age, sex, ethnicity, and socioeconomic status to analyze patient experience using seven items covering three domains of primary care: access, continuity, and communication. RESULTS: People with diabetes were significantly more likely to report better experience on six out of seven primary care items than people without diabetes after adjusting for age, sex, ethnicity, and socioeconomic status (adjusted differences 0.88-3.20%; odds ratios [ORs] 1.07-1.18; P < 0.001). Those with diabetes and additional comorbid long-term conditions were more likely to report worse experiences, particularly for access to primary care appointments (patients with diabetes alone compared with patients without diabetes: OR 1.22 [95% CI 1.17-1.28] and patients with diabetes plus three or more conditions compared with patients without diabetes: OR 0.87 [95% CI 0.83-0.91]). CONCLUSIONS: People with diabetes in England report primary care experiences that are at least as good as those without diabetes for most domains of care. However, improvements in primary care are needed for diabetes patients with comorbid long-term conditions, including better access to appointments and improved communication.Diabetes UKThis is the author accepted manuscript. The final version is available from the American Diabetes Association via http://dx.doi.org/10.2337/dc14-109
Single-mode sapphire fiber Bragg grating
We present here the inscription of single-mode waveguides with Bragg gratings
in sapphire. The waveguide Bragg gratings have a novel multi-layer depressed
cladding design in the 1550 nm telecommunications waveband. The Bragg gratings
have a narrow bandwidth (<0.5 nm) and have survived annealing at 1000{\deg}C.
The structures are inscribed with femtosecond laser direct writing, using
adaptive beam shaping with a non-immersion objective. A single-mode sapphire
fiber Bragg grating is created by writing a waveguide with a Bragg grating
within a 425 {\mu}m diameter sapphire optical fiber, providing significant
potential for accurate remote sensing in ultra-extreme environments.Comment: Submitted to Optica 12 November 202
Charge-Induced Fragmentation of Sodium Clusters
The fission of highly charged sodium clusters with fissilities X>1 is studied
by {\em ab initio} molecular dynamics. Na_{24}^{4+} is found to undergo
predominantly sequential Na_{3}^{+} emission on a time scale of 1 ps, while
Na_{24}^{Q+} (5 \leq Q \leq 8) undergoes multifragmentation on a time scale
\geq 0.1 ps, with Na^{+} increasingly the dominant fragment as Q increases. All
singly-charged fragments Na_{n}^{+} up to size n=6 are observed. The observed
fragment spectrum is, within statistical error, independent of the temperature
T of the parent cluster for T \leq 1500 K. These findings are consistent with
and explain recent trends observed experimentally.Comment: To appear in Physical Review Letter
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