287 research outputs found
Context-Driven Tour Planning Service: An Approach Based on Synthetic Coordinates Recommendation
The paper presents a hybrid context/model-based tour planning service aimed at recommendation generation by providing the tourists the sequence of attractions that are more interesting for him/her based on previous activity with the service. The service is developed based on SCoR recommender system that is aimed at recommendation generation based on calculating the synthetic coordinate between tourists of the service in according with their ratings. SCoR is a model-based collaborative filtering algorithm, constructing a model based on the user's personal ratings as well as exploiting collaborative information from the ratings of the rest of the users. One of the main advantages of SCoR's model is its ability to incorporate additional training information (new ratings) without having to perform the training process from the beginning. The prototype has been implemented for Android-based smartphone and has been evaluated for St. Petersburg city. For the evaluation the attraction database has been formed that includes attraction location information from OpenStreeMaps platform, location description and media from Wikipedia, and ratings from Google Place
Cardiovascular Remodeling Experienced by Real-World, Unsupervised, Young Novice Marathon Runners.
Aims: Marathon running is a popular ambition in modern societies inclusive of non-athletes. Previous studies have highlighted concerning transient myocardial dysfunction and biomarker release immediately after the race. Whether this method of increasing physical activity is beneficial or harmful remains a matter of debate. We examine in detail the real-world cardiovascular remodeling response following competition in a first marathon. Methods: Sixty-eight novice marathon runners (36 men and 32 women) aged 30 ± 3 years were investigated 6 months before and 2 weeks after the 2016 London Marathon race in a prospective observational study. Evaluation included electrocardiography, cardiopulmonary exercise testing, echocardiography, and cardiovascular magnetic resonance imaging. Results: After 17 weeks unsupervised marathon training, runners revealed a symmetrical, eccentric remodeling response with 3-5% increases in left and right ventricular cavity sizes, respectively. Blood pressure (BP) fell by 4/2 mmHg (P < 0.01) with reduction in arterial stiffness, despite only 11% demonstrating a clinically meaningful improvement in peak oxygen consumption with an overall non-significant 0.4 ml/min/kg increase in peak oxygen consumption (P = 0.14). Conclusion: In the absence of supervised training, exercise-induced cardiovascular remodeling in real-world novice marathon runners is more modest than previously described and occurs even without improvement in cardiorespiratory fitness. The responses are similar in men and women, who experience a beneficial BP reduction and no evidence of myocardial fibrosis or persistent edema, when achieving average finishing times
The distance to galactic globular clusters through RR Lyrae pulsational properties
By adopting the same approach outlined in De Santis & Cassisi (1999), we
evaluate the absolute bolometric magnitude of the Zero Age Horizontal Branch
(ZAHB) at the level of the RR Lyrae variable instability strip in selected
galactic globular clusters. This allows us to estimate the ZAHB absolute visual
magnitude for these clusters and to investigate its dependence on the cluster
metallicity. The derived relation, corrected in order to
account for the luminosity difference between the ZAHB and the mean RR Lyrae
magnitude, has been compared with some of the most recent empirical
determinations in this field, as the one provided by Baade-Wesselink analyses,
RR Lyrae periods, Hipparcos data for field variables and Main Sequence fitting
based on Hipparcos parallaxes for field subdwarfs. As a result, our relation
provides a clear support to the "long" distance scale. We discuss also another
method for measuring the distance to galactic globular clusters. This method is
quite similar to the one adopted for estimating the absolute bolometric
magnitude of the ZAHB but it relies only on the pulsational properties of the
Lyrae variables in each cluster. The reliability and accuracy of this method
has been tested by applying it to a sample of globulars for which, due to the
morphology of their horizontal branch (HB), the use of the commonly adopted
ZAHB fitting is a risky procedure.Comment: 7 pages, 2 postscript figures, accepted for publication on MNRA
Examining the Relationship Between Trait Energy and Fatigue and Feelings of Depression in Young Healthy Adults
Depression is usually co-morbid with fatigue. However, we are unaware of studies exploring the relationship between trait energy and fatigue and feelings of depression. Recent evidence suggests that energy and fatigue are two distinct moods. PURPOSE: To examine the association between trait mental and physical energy and fatigue and feelings of depression, within an otherwise healthy young adult cohort. METHODS: Using a cross-sectional design, healthy respondents (n=495) completed a series of self-reported surveys measuring depression, lifestyle factors (sleep, diet, physical activity), and trait mental and physical energy and fatigue. Using a step-wise regression, we controlled for demographics and lifestyle and added trait mental and physical energy and fatigue to the second model. RESULTS: When trait mental and physical energy and fatigue were added to the models, the adjusted R2 increased by 5% (R2 = .112, F(13, 457) = 4.455, p \u3c .001). In our second model, trait mental fatigue was the only significant predictor of depressive mood states (Β = .159, t (457) = 2.512, p = 0.01). CONCLUSION: Young adults, who struggle with high mental fatigue, may also be more likely to report feeling depressed suggesting that fatigue and depression are co-morbid, while low energy and depression are not. Future research should aim to identify epigenetic/genetic factors that influence mental fatigue and how those may be associated with feelings of depression
Landau Level Crossings and Extended-State Mapping in Magnetic Two-dimensional Electron Gases
We present longitudinal and Hall magneto-resistance measurements of a
``magnetic'' two-dimensional electron gas (2DEG) formed in modulation-doped
ZnCdMnSe quantum wells. The electron spin splitting is
temperature and magnetic field dependent, resulting in striking features as
Landau levels of opposite spin cross near the Fermi level. Magnetization
measurements on the same sample probe the total density of states and Fermi
energy, allowing us to fit the transport data using a model involving extended
states centered at each Landau level and two-channel conduction for spin-up and
spin-down electrons. A mapping of the extended states over the whole quantum
Hall effect regime shows no floating of extended states as Landau levels cross
near the Fermi level.Comment: 10 pages, 4 figures, submitted to Phys. Rev.
Landmine injuries at the Emergency Management Center in Erbil, Iraq
<p>Abstract</p> <p>Background</p> <p>Landmines can cause death, injury and disability in addition to many indirect public health consequences. This study aimed at understanding the trends, demography and other epidemiological characteristics of hospitalized landmine injured patients in Erbil governorate.</p> <p>Methods</p> <p>The case records of landmine injured patients who had been admitted to the Emergency Management Centre in Erbil city from July 1998 to July 2007 were reviewed and descriptively analyzed.</p> <p>Results</p> <p>Two hundred eighty five landmine injured patients were admitted to the center, their mean ± SD age was 26.5 ± 13.2 years (range 6-71 years), 95.1% were males, nearly 50% were between 19 to 35 years of age and 96.8% were civilians. Around 72% of victims sustained limb amputations; 58.6% lower limb and 13.3% upper limb out of the total. The hospital mortality rate was 2.1%. The number of admissions for landmine injury was steadily decreasing between July 1998 and July 2001, followed by prominent increase between July 2002 and July 2003. The highest proportion of admissions occurred in summer (35.4%) and majority of incidents occurred along the borders with Iran and Turkey (61.8%).</p> <p>Conclusion</p> <p>Civilian male adolescents and young adults constituted the majority of hospitalized landmine victims in Erbil governorate. While a high proportion of victims sustained lower limb amputations, upper limb amputations particularly among children and injury to head and face were relatively common which might be attributed to handling explosives. This emphasizes the need to examine the reasons behind handling explosives.</p
Endoscopic treatment of prepatellar bursitis
Operative treatment of prepatellar bursitis is indicated in intractable bursitis. The most common complication of surgical treatment for prepatellar bursitis is skin problems. For traumatic prepatellar bursitis, we propose a protocol of outpatient endoscopic surgery under local anaesthesia. From September 1996 to February 2001, 60 cases of failed nonoperative treatment for prepatellar bursitis were included. The average age was 33.5 ± 11.1 years (range 21–55). The average operation duration was 18 minutes. Two to three mini-arthroscopic portals were used in our series. No sutures or a simple suture was needed for the portals after operation. After follow-up for an average of 36.3 months, all patients are were symptom-free and had regained knee function. None of the population had local tenderness or hypo-aesthesia around their wound. Their radiographic and sonographic examinations showed no recurrence of bursitis. Outpatient arthroscopic bursectomy under local anaesthesia is an effective procedure for the treatment of post-traumatic prepatellar bursitis after failed conservative treatments. Both the cosmetic results and functional results were satisfactory
Chemical abundances of metal-poor RR Lyrae stars in the Magellanic Clouds
We present for the first time a detailed spectroscopic study of chemical
element abundances of metal-poor RR Lyrae stars in the Large and Small
Magellanic Cloud (LMC and SMC). Using the MagE echelle spectrograph at the 6.5m
Magellan telescopes, we obtain medium resolution (R ~ 2000 - 6000) spectra of
six RR Lyrae stars in the LMC and three RR Lyrae stars in the SMC. These stars
were chosen because their previously determined photometric metallicities were
among the lowest metallicities found for stars belonging to the old populations
in the Magellanic Clouds. We find the spectroscopic metallicities of these
stars to be as low as [Fe/H]_{spec} = -2.7dex, the lowest metallicity yet
measured for any star in the Magellanic Clouds. We confirm that for metal-poor
stars, the photometric metallicities from the Fourier decomposition of the
lightcurves are systematically too high compared to their spectroscopic
counterparts. However, for even more metal-poor stars below [Fe/H]_{phot} <
-2.8dex this trend is reversed and the spectroscopic metallicities are
systematically higher than the photometric estimates. We are able to determine
abundance ratios for ten chemical elements, which extend the abundance
measurements of chemical elements for RR Lyrae stars in the Clouds beyond
[Fe/H] for the first time. For the overall [alpha/Fe] ratio, we obtain an
overabundance of 0.36dex, which is in very good agreement with results from
metal-poor stars in the Milky Way halo as well as from the metal-poor tail in
dwarf spheroidal galaxies. Comparing the abundances with those of the stars in
the Milky Way halo we find that the abundance ratios of stars of both
populations are consistent with another. Therefore we conclude that from a
chemical point of view early contributions from Magellanic-type galaxies to the
formation of the Galactic halo as claimed in cosmological models are plausible.Comment: accepted for publication in AJ, 19 pages, 12 figure
An overview of the reproductive cycle of cultured specimens of a potential candidate for Mediterranean aquaculture, Umbrina cirrosa
The shi drum (Umbrina cirrosa), belonging to the Sciaenidae family of fish (Nelson et al., 2016) has attracted attention as it is an excellent diversification species in Mediterranean aquaculture to combat the low prices of the most cultured species due to the appearance of new producing countries in the Mediterranean area. In this manuscript we describe for the first time the reproductive cycle of captive shi drum specimens that are able to spontaneously spawn in captivity. Our data show that spermatogenesis started in one year old shi drum spe- cimens, although the fish were not mature enough to complete the reproductive cycle. Thus, three year old specimens showed multiple spawns with around 65% of the eggs fertilized. In mature males, levels of 11-ke- totestosterone (11KT), testosterone (T) and progesterone (P) were detected in serum and gonad, while 17β- estradiol (E2) was only detected in gonad. Testicular levels of E2 and P suggest that these hormones might have a role in spawning and in the subsequent spermatogonial proliferation. In mature females, however, P and E2 were detected in serum and gonad, while T and 11KT were only detected in gonad. The pattern shown by P in the ovary indicates a link between this hormone and ovarian renewal and a delay in vitellogenesis, which would explain why the vitellogenic stage of shi drum is quite short. The level of T and 11KT in the ovary suggests a role in oocyte maturation and spawning. The differences observed between sexes in the prevalence of some infection and the important economic losses produced by some vertically transmitted pathogens; have increase the at- tention to the interactions between the immune and reproductive systems. In this study we observed differences between sexes in the protease and bactericide activity levels. Thus, this manuscript represents the most complete overview to date of the shi drum reproductive cycle.Versión del editor2,04
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