66 research outputs found

    800nm fiber Bragg Grating sensing interrogation system using TFBG and CCD array

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    An 800nm band fiber Bragg grating sensing interrogation system using TFBG as the core wavelength division component is presented. A charge coupled device (CCD) linear array is put on the focal plane of the lens to detect the light. TFBG is used to tap light out of the fiber core to fiber cladding. The sensing wavelength is 795 to 830nm, with accuracy of 20pm and scan speed 100Hz. Using FBG sensor, we achieve the temperature sensitivity as 1.8°C and strain sensitivity as 18με

    Properties and structural features of iron doped BABAL glasses

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    Temporal-Spatial of dengue virus (DENV) analyses have been performed in previous epidemiological studies in mainland China, but few studies have examined the whole genome of the DENV. Herein, 40 whole genome sequences of DENVs isolated from mainland China were downloaded from GenBank. Phylogenetic analyses and evolutionary distances of the dengue serotypes 1 and 2 were calculated using 14 maximum likelihood trees created from individual genes and whole genome. Amino acid variations were also analyzed in the 40 sequences that included dengue serotypes 1, 2, 3 and 4, and they were grouped according to temporal and spatial differences. The results showed that none of the phylogenetic trees created from each individual gene were similar to the trees created using the complete genome and the evolutionary distances were variable with each individual gene. The number of amino acid variations was significantly different (p = 0.015) between DENV-1 and DENV-2 after 2001; seven mutations, the N290D, L402F and A473T mutations in the E gene region and the R101K, G105R, D340E and L349M mutations in the NS1 region of DENV-1, had significant substitutions, compared to the amino acids of DENV-2. Based on the spatial distribution using Guangzhou, including Foshan, as the indigenous area and the other regions as expanding areas, significant differences in the number of amino acid variations in the NS3 (p = 0.03) and NS1 (p = 0.024) regions and the NS2B (p = 0.016) and NS3 (p = 0.042) regions were found in DENV-1 and DENV-2. Recombination analysis showed no inter-serotype recombination events between the DENV-1 and DENV-2, while six and seven breakpoints were found in DENV-1 and DENV-2. Conclusively, the individual genes might not be suitable to analyze the evolution and selection pressure isolated in mainland China; the mutations in the amino acid residues in the E, NS1 and NS3 regions may play important roles in DENV-1 and DENV-2 epidemics

    A Wireless Transient Attenuated-exponential Overpressure Beamforming with for Far-field Blast Source Localization

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    Time-domain beamforming is more suitable for blast wave transient signal than frequency-domain beamformer because wide-band spectrum of noise makes the beamforming image less clear. To avoid the gust effects and enable the location of blast source accurately, this paper proposes a new one-dimensional Far-field delay-and-sum (DAS) beamforming method with an attenuate exponential function model for wireless overpressure transient signal. In addition, we also design wireless overpressure peak and root-mean-square (RMS) directional estimators to assess the performance of the proposed new DAS beamforming method. Furthermore, the effects of the wireless pressure sensor node (WPSL) spacing, the number of WPSLs and side lobe level brought from noise on the beam width are investigated in the two estimators. The proposed formula is verified by a uniformly spaced linear sensing array, and the results verify the feasibility of the proposed method in blast source localization. This paper is conducted to provide new insight into blast source localization algorithm, and further open a door for transient blast overpressure source localization scenarios in future

    Journey to the east: Diverse routes and variable flowering times for wheat and barley en route to prehistoric China.

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    Today, farmers in many regions of eastern Asia sow their barley grains in the spring and harvest them in the autumn of the same year (spring barley). However, when it was first domesticated in southwest Asia, barley was grown between the autumn and subsequent spring (winter barley), to complete their life cycles before the summer drought. The question of when the eastern barley shifted from the original winter habit to flexible growing schedules is of significance in terms of understanding its spread. This article investigates when barley cultivation dispersed from southwest Asia to regions of eastern Asia and how the eastern spring barley evolved in this context. We report 70 new radiocarbon measurements obtained directly from barley grains recovered from archaeological sites in eastern Eurasia. Our results indicate that the eastern dispersals of wheat and barley were distinct in both space and time. We infer that barley had been cultivated in a range of markedly contrasting environments by the second millennium BC. In this context, we consider the distribution of known haplotypes of a flowering-time gene in barley, Ppd-H1, and infer that the distributions of those haplotypes may reflect the early dispersal of barley. These patterns of dispersal resonate with the second and first millennia BC textual records documenting sowing and harvesting times for barley in central/eastern China

    Surgical Outcomes after Total Colectomy with Ileorectal Anastomosis in Patients with Medically Intractable Slow Transit Constipation

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    Purpose: The aim of this study was to evaluate outcomes of a total colectomy with ileorectal anastomosis in patients with slow transit constipation. Methods: A retrospective review of 37 consecutive patients with slow transit constipation who underwent a total colectomy between 1994 and 2008 was undertaken. Preoperative and postoperative Wexner’s constipation scores were collected and used to evaluate the outcomes after surgical treatment. Also patients ’ postoperative satisfaction scores were collected using a 4-point scale. Results: The 37 patients consisted of 31 women and 6 men, with a median age of 41 years (range, 17 to 71 years). Pre- and post-operative Wexner’s scores were collected from 33 patients (89.1%), and the mean preoperative Wexner’s score was 19.3 (range, 11 to 24), which decreased to an average post-operative score of 2.3 (range, 0 to 8). Neither intraoperative complications nor postoperative mortalities were noted. Five patients (13.5%) had early postoperative complications, and the most common complication was postoperative ileus (10.8%). Seven patients (18.9%) had late postoperative complications, and postoperative ileus (10.8%) was also the most common. Twenty seven of 33 patients were satisfied with their surgical outcome (81.8%). Conclusion: A total colectomy with ileorectal anastomosis might be an effective surgical procedure with acceptable morbidity to treat medically intractable slow transit constipation

    Effects of co-habitation between Anopheles gambiae s.s. and Culex quinquefasciatus aquatic stages on life history traits

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    <p>Abstract</p> <p>Background</p> <p>The effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat. To design this strategy, the mechanisms (like biotic interactions with conspecifc and heterospecific larvae) regulating mosquito aquatic stages survivorship, development time and the size of emerging adults should be understood. This study explored the effect of co-habitation between <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>on different life history traits of both species under different densities and constant food supply in the habitats of the same size under semi-natural conditions.</p> <p>Methods</p> <p>Experiments were set up with three combinations; <it>Cx. quinquefasciatus </it>alone (single species treatment), <it>An. gambiae </it>s.s. alone (single species treatment); and <it>An. gambiae </it>s.s. with <it>Cx. quiquefasciatus </it>(co-habitation treatment) in different densities in semi field situation.</p> <p>Results</p> <p>The effect of co-habitation of <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>was found to principally affect three parameters. The wing-lengths (a proxy measure of body size) of <it>An. gambiae </it>s.s. in co-habitation treatments were significantly shorter in both females and males than in <it>An. gambiae </it>s.s single species treatments. In <it>Cx. quinquefasciatus</it>, no significant differences in wing-length were observed between the single species and co-habitation treatments. Daily survival rates were not significantly different between co-habitation and single species treatments for both <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus</it>. Developmental time was found to be significantly different with single species treatments developing better than co-habitation treatments. Sex ratio was found to be significantly different from the proportion of 0.5 among single and co-habitation treatments species at different densities. Single species treatments had more males than females emerging while in co-habitation treatments more females emerged than males. In this study, there was no significant competitive survival advantage in co-habitation.</p> <p>Conclusion</p> <p>These results suggest that co-habitation of <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>in semi-natural conditions affect mostly <it>An. gambiae </it>s.s. body size. Hence, more has to be understood on the effects of co-habitation of <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>in a natural ecology and its possible consequences in malaria and filariasis epidemiology.</p

    Population genetics of the malaria vector Anopheles aconitus in China and Southeast Asia

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    Anopheles aconitus is a well-known vector of malaria and is broadly distributed in the Oriental Region, yet there is no information on its population genetic characteristics. In this study, the genetic differentiation among populations was examined using 140 mtDNA COII sequences from 21 sites throughout southern China, Myanmar, Vietnam, Thailand, Laos and Sri Lanka. The population in Sri Lanka has characteristic rDNA D3 and ITS2, mtDNA COII and ND5 haplotypes, and may be considered a distinct subspecies. Clear genetic structure was observed with highly significant genetic variation present among population groups in Southeast Asia. The greatest genetic diversity exists in Yunnan and Myanmar population groups. All population groups are significantly different from one another in pairwise Fst values, except northern Thailand with central Thailand. Mismatch distributions and extremely significant F(s) values suggest that the populations passed through a recent demographic expansion. These patterns are discussed in relation to the likely biogeographic history of the region and compared to other Anopheles species
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