Stability bound analysis of singularly perturbed systems with time-delay

This paper considers the stability bound problem of singularly perturbed systems with time-delay. Some stability criteria are derived by constructing appropriate Lyapunov-Krasovskii functionals. The proposed criteria are less conservative than the existing ones. Two numerical examples are given to illustrate the advantages and effectiveness of the proposed methods

Multi-epoch analysis of the X-ray spectrum of the active galactic nucleus in NGC 5506

We present a multi-epoch X-ray spectroscopy analysis of the nearby narrow-line Seyfert I galaxy NGC 5506. For the first time, spectra taken by Chandra, XMM-Newton, Suzaku, and NuSTAR - covering the 2000-2014 time span - are analyzed simultaneously, using state-of-the-art models to describe reprocessing of the primary continuum by optical thick matter in the AGN environment. The main goal of our study is determining the spin of the supermassive black hole (SMBH). The nuclear X-ray spectrum is photoelectrically absorbed by matter with column density $\simeq 3 \times 10^{22}$ cm$^{-2}$. A soft excess is present at energies lower than the photoelectric cut-off. Both photo-ionized and collisionally ionized components are required to fit it. This component is constant over the time-scales probed by our data. The spectrum at energies higher than 2 keV is variable. We propose that its evolution could be driven by flux-dependent changes in the geometry of the innermost regions of the accretion disk. The black hole spin in NGC 5506 is constrained to be 0.93$\pm _{ 0.04 }^{0.04}$ at 90% confidence level for one interesting parameter.Comment: 13 pages, 9 figures. v2: refereed versio

Speckle reducing bilateral filter for cattle follicle segmentation

<p>Abstract</p> <p>Background</p> <p>Ultrasound imaging technology has wide applications in cattle reproduction and has been used to monitor individual follicles and determine the patterns of follicular development. However, the speckles in ultrasound images affect the post-processing, such as follicle segmentation and finally affect the measurement of the follicles. In order to reduce the effect of speckles, a bilateral filter is developed in this paper.</p> <p>Results</p> <p>We develop a new bilateral filter for speckle reduction in ultrasound images for follicle segmentation and measurement. Different from the previous bilateral filters, the proposed bilateral filter uses normalized difference in the computation of the Gaussian intensity difference. We also present the results of follicle segmentation after speckle reduction. Experimental results on both synthetic images and real ultrasound images demonstrate the effectiveness of the proposed filter.</p> <p>Conclusions</p> <p>Compared with the previous bilateral filters, the proposed bilateral filter can reduce speckles in both high-intensity regions and low intensity regions in ultrasound images. The segmentation of the follicles in the speckle reduced images by the proposed method has higher performance than the segmentation in the original ultrasound image, and the images filtered by Gaussian filter, the conventional bilateral filter respectively.</p

A Novel method for monitoring urban dew condensation and its application

Rosa predstavlja unos vlage bitan za održavanje razine vode gradskih ekosustava. Rosu, koja je važan ekološki faktor gradskih ekosustava, lišće biljaka lako apsorbira i tako se opskrbljuje hranjivim tvarima (N, P i K). Osim toga, stvaranje rose važno je u pročišćavanju zraka. Ipak, ima malo internacionalno prihvaćenih standardnih metoda ili instrumenata trenutačno raspoloživih za mjerenje količine rose u urbanim ekosustavima, zbog male količine rose. U svrhu točnog mjerenja kondenzacije vodene pare noću i procjene učinaka stvrdnjavanja površine na tokove vode blizu površine, u radu se prati kondenzacija rose i kombinira rosa s indeksom površine lista te se predlaže nova metoda za praćenje i izračunavanje količine rose u različitim površinama urbanih ekoloških sustava. Grad Changchun u Kini uzet je kao primjer i predloženom metodom se promatrala kondenzacija rose u njegovim različitim funkcionalnim područjima u razdoblju u kojem nema smrzavanja (travanj 2016. do listopada 2016.). Konačno su se analizirali glavni meteorološki faktori koji utječu na kondenzaciju rose sumirajući pravilo kondenzacije vlage; uz to, dobio se intenzitet rose i njezina godišnja količina u različitim krajolicima. Rezultati pokazuju da su područja zelenog pojasa važna mjesta za nakupljanje rose. Redosljed krajolika po intenzitetu rose: područje zelenog pojasa, goli krajolik i krajolik s cestom (P < 0.01). Relativna vlažnost je glavni čimbenik od utjecaja na promjenu količine vodene pare. Količine rose se smanjuju idući od zelenog pojasa do golog krajolika i ceste i iznose 61.43, 0.56, i 1.23 mm. Prema omjeru za svaki krajolik godišnja količina rose je u Changchunu 22.98 mm. Sustav za mjerenje količine rose poboljšan je u urbanim dijelovima i dodana mu je količina dobivena kondenzacijom pare noću s različitih površina. Metoda daje teoretske reference za dalje istraživanje o vodenim tokovima blizu površine.Dew is crucial moisture input for the water balance of urban ecosystems. Dew, which is an important environmental factor of urban ecosystem, can be easily absorbed by plant leaves and provide nutrients (N, P, and K) to plants. Moreover, dew formation is important in air purification. However, few internationally accepted standard methods or instruments are currently available for measuring dew amount in urban ecosystems because of the small dew amount. In order to accurately measure the night water vapour condensation and evaluate the effects of surface hardening to near-surface water cycle, this study monitored dew condensation and combined dew with leaf area index, and a novel method was proposed for monitoring and calculating dew amount in different underlying surfaces in urban ecosystems. The Changchun City in China was considered as an example and the proposed method was used to observe dew condensation in different functional areas of the city during the frost-free period (April 2016 to October 2016). Finally, the main meteorological factors affecting dew condensation were analyzed by summarizing the rule of vapour condensation; moreover, dew intensity and annual dewfall of different landscapes were obtained. Results indicate that greenbelt landscapes are important sites for dew deposition. The landscapes of dew intensity, in descending order, are greenbelt landscape, bare landscape, and road landscape (P < 0.01). Relative humidity is the main factor affecting water vapour migration. Dewfall amounts in the greenbelt, road, and bare landscapes are 61.43, 0.56, and 1.23 mm, respectively. The annual dewfall is 22.98 mm in Changchun according to the proportion of each landscape. The dew-monitoring method system in urban area is improved and the wet deposition from vapour condensation of different surfaces underlying at night is added. The method provides theoretical reference for further research on revealing the near-surface water cycle

The Use of Nanoscaled Fibers or Tubes to Improve Biocompatibility and Bioactivity of Biomedical Materials

Nanofibers and nanotubes have recently gained substantial interest for potential applications in tissue engineering due to their large ratio of surface area to volume and unique microstructure. It has been well proved that the mechanical property of matrix could be largely enhanced by the addition of nanoscaled fibers or tubes. At present, more and more researches have shown that the biocompatibility and bioactivity of biomedical materials could be improved by the addition of nanofibers or nanotubes. In this review, the efforts using nanofibers and nanotubes to improve biocompatibility and bioactivity of biomedical materials, including polymeric nanofibers/nanotubes, metallic nanofibers/nanotubes, and inorganic nanofibers/nanotubes, as well as their researches related, are demonstrated in sequence. Furthermore, the possible mechanism of improving biocompatibility and bioactivity of biomedical materials by nanofibers or nanotubes has been speculated to be that the specific protein absorption on the nanoscaled fibers or tubes plays important roles

Effect of BMI on the value of serum progesterone to predict clinical pregnancy outcome in IVF/ICSI cycles: a retrospective cohort study

BackgroundNumerous research have investigated the predictor role of progesterone (P) level on the human Chorionic Gonadotropin (hCG) trigger day of assisted reproductive technology (ART) outcomes. However, the relationship of progesterone levels on hCG day to clinical pregnancy outcomes in IVF/ICSI cycles for patients with different BMI groups is still elusive. This study aimed to investigate the effects of progesterone elevation on triggering day on clinical pregnancy rate (CPR) of IVF/ICSI cycles in patients with different female BMI.MethodsWe conducted a retrospective cohort study included 6982 normal-weight parents (18.5Kg/m2≤BMI&lt;25Kg/m2) and 2628 overweight/obese patients (BMI≥25Kg/m2) who underwent fresh day 3 cleavage embryo transfer (ET) in IVF/ICSI cycles utilizing GnRH agonist to control ovarian stimulation.ResultsThe interaction between BMI and P level on triggering day on CPRs was significant (p&lt;0.001). The average level of serum P was reduced with the increase in maternal BMI. Serum P adversely affected CPR in distinct BMI groups. In the normal weight group, CPRs were decreasedas serum P concentrations gradually increased (p&lt;0.001 for overall trend). The CPRs (lower than 65.8%) of progesterone level &gt; 1.00 ng/ml on triggering day were significantly lower than that (72.4%) of progesterone level &lt;0.5 ng/ml. In the overweight/obese group, CPRs showed a decrease statistically with progesterone levels of ≥2.00 ng/ml compared to progesterone levels of &lt;0.5 ng/ml (51.0% VS. 64.9%, p=0.016). After adjusting for confounders, progesterone elevation (PE) negatively correlated with CPRs only in the normal weight group (OR: 0.755 [0.677–0.841], p&lt;0.001), not in the overweight/obese group (p=0.063).ConclusionWomen with higher BMI exhibited a lower progesterone level on triggering day. Additionally, PE on hCG day is related to decreased CPRs in GnRH agonist IVF/ICSI cycles with cleavage embryo transfers regardless of women’s BMI level (normal weight VS. overweight/obesity)

Identification and Characterization of a Large Sample of Distant Active Dwarf Galaxies in XMM-SERVS

Active dwarf galaxies are important because they contribute to the evolution of dwarf galaxies and can reveal their hosted massive black holes. However, the sample size of such sources beyond the local universe is still highly limited. In this work, we search for active dwarf galaxies in the recently completed XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS). XMM-SERVS is currently the largest medium-depth X-ray survey covering 13 $\mathrm{deg}^2$ in three extragalactic fields, which all have well-characterized multi-wavelength information. After considering several factors that may lead to misidentifications, we identify 73 active dwarf galaxies at $z<1$, which constitutes the currently largest X-ray-selected sample beyond the local universe. Our sources are generally less obscured than predictions based on the massive-AGN (active galactic nucleus) X-ray luminosity function and have a low radio-excess fraction. We find that our sources reside in similar environments to inactive dwarf galaxies. We further quantify the accretion distribution of the dwarf-galaxy population after considering various selection effects and find that it decreases with X-ray luminosity, but redshift evolution cannot be statistically confirmed. Depending upon how we define an AGN, the active fraction may or may not show a strong dependence on stellar mass. Their Eddington ratios and X-ray bolometric corrections significantly deviate from the expected relation, which is likely caused by several large underlying systematic biases when estimating the relevant parameters for dwarf galaxies. Throughout this work, we also highlight problems in reliably measuring photometric redshifts and overcoming strong selection effects for distant active dwarf galaxies.Comment: 34 pages, 21 figures, 6 tables, accepted for publication in Ap

Synapsis and Meiotic Recombination in Male Chinese Muntjac (Muntiacus reevesi)

The muntjacs (Muntiacus, Cervidae) have been extensively studied in terms of chromosomal and karyotypic evolution. However, little is known about their meiotic chromosomes particularly the recombination patterns of homologous chromosomes. We used immunostained surface spreads to visualise synaptonemal complexes (SCs), recombination foci and kinetochores with antibodies against marker proteins. As in other mammals pachytene was the longest stage of meiotic prophase. 39.4% of XY bivalents lacked MLH1 foci compared to less than 0.5% of autosomes. The average number of MLH1 foci per pachytene cell in M. reevesi was 29.8. The distribution of MLH1 foci differed from other mammals. On SCs with one focus, the distribution was more even in M. reevesi than in other mammals; for SCs that have two or more MLH1 foci, usually there was a larger peak in the sub-centromere region than other regions on SC in M. reevesi. Additionally, there was a lower level of interference between foci in M. reevesi than in mouse or human. These observations may suggest that the regulation of homologous recombination in M. reevesi is slightly different from other mammals and will improve our understanding of the regulation of meiotic recombination, with respect to recombination frequency and position