Search

In view of the fact that the point cloud 3D model will be interfered by environmental factors, measurement methods and other random factors in the process of data scanning and acquisition, there will be some invalid points, outliers and internal noise points. In this paper, a point cloud denoising method based on adaptive density clustering and statistical filtering is proposed to process vehicle point cloud data. which can effectively preserve vehicle features while obtaining optimal denoising effect. Compared with the existing point cloud noise processing algorithms, this algorithm can remove noise better, and has shorter time-consuming and good applicability.

Quasi-periodic eruptions (QPEs), which are a new kind of X-ray bursts with a recurrence time of several hours, have been detected from supermassive black holes (SMBHs) in galactic nuclei. Recently, the two QPEs discovered by the \textit{eROSITA} show asymmetric light curves with a fast rise and a slow decline. Current models cannot explain the observational characteristics of QPEs. Here we show that QPEs can be generated from the Roche lobe overflows at each periapsis passage of an evolved star orbiting an SMBH. The properties of the companion stars are constrained via analytic estimations. We find that hydrogen-deficient post-AGB stars are promising candidates. Modules for Experiments in Stellar Astrophysics (MESA) stellar evolution code is used to construct the hydrogen-deficient stars which can fulfill the requirements, as obtained through analytical estimates, to produce the properties of QPEs, including the fast-rise and slow-decay light curves, periods, energetics, and rates. Furthermore, the extreme mass ratio $\sim 10^5$ between the SMBH and the donor will lead to a phenomenon called extreme mass-ratio inspiral (EMRI), producing millihertz gravitational waves. These QPEs would be detected as EMRI sources with electromagnetic counterparts for space-based GW detectors, such as Laser Interferometer Space Antenna (LISA) and Tianqin. They would provide a new way to measure the Hubble constant and further test the Hubble constant tension., 9 pages, 6 figures, 3 tables, accepted for publication in A&A

Summary At the end of 2012 and beginning of 2013, the authors conducted a nationwide survey of sturgeon aquaculture in China from 2010 to 2012. The survey results, combined with previous data, show that the dominant cultured species are Acipenser baerii, Huso dauricus♀ × A. schrenckii♂, A. baerii♀ × A. schrenckii♂, A. schrenckii, and A. gueldenstaedtii, accounting for 90% of the total production. Sturgeon farms have grown to include almost all provinces except Xizang, and are grouped principally in Shandong, Hubei, Sichuan and Chongqing, Beijing. The main culture systems are cage culture, and cement pond culture with running water. Sturgeon production rose from 34800 tonnes (t) in 2010 to 44500 t in 2012. The commercial sturgeon price dropped from 45 yuan per kg (5.5€/7.3$) in 2010 to 25 yuan per kg (3€/4$) in 2012. Nine caviar-processing enterprises qualified for or were striving to process caviar, for a total production of 56.6 t caviar in 2012, of which 90% was exported. Major problems were also identified during the survey, including: disorderly hybridization and germplasm degradation; a stagnant domestic consumption demand; dramatic price fluctuations in different regions and at different times. Specialized sturgeon cooperatives had obtained government support to a certain extent, but did not use this to their advantage because of a lack of policy guidance and technical support. The processing of sturgeon products developed slowly. In view of the existing problems, certain proposals are discussed: publication of propagation standards, culture and processing to define the parental source of the commercial sturgeon and their by-products; promulgate sturgeon consumption to expand market demand; establish a ‘Sturgeon Industry Association’ to constrain bad competition and cultivate good competitive mechanisms; build a protective pricing system to secure effectively the interests of some of the weaker farms; and conduct professional technical training courses on culture improvement and deep processing technology.

Summary A protocol for gynogenesis of P. spathula was developed in order to produce inbred lines and to develop a technique to preserve the endangered Chinese paddlefish (Psephurus gladius). Diploid gynogenesis was induced in P. spathula using ultraviolet (UV)-irradiated Amur sturgeon (Acipenser schrenckii) sperm for 4.5-min, 5-min or 5.5-min and subsequent heat shock treatment. UV irradiation of sperm for 5 min at a UV intensity (254 nm) of 863 l wc m )2 was the optimum dose to achieve diploid gynogenesis on the basis of observations on hatching rate of eggs. Three microsatellite loci were used to monitor exclusive maternal inheritance of gynogenetic progenies. The results showed all maternal genome among offspring with no paternal genome. The cytogenetic analysis showed that meiotic gynogenetic diploids possessed 120 chromosomes in metaphase plates, while haploid control groups N1–3 possessed 60 chromosomes.

Freshwater Fisheries Research Center, Chinese Academy of Fishery Science, Wuxi, Jiangsu, ChinaSummaryChinese sturgeon (Acipenser sinensis Gray), a species withimportant scientific and economic values, has been listed as aFirst Class Protected Animal by the China Government in1989. Due to the effects of human activities, the wildpopulation of A. sinensis has declined drastically in the past30 years. Though a series of policies and protective measureshave been implemented, the number of A. sinensis continues todrop. Considering the declining trend of A. sinensis populationresource, some new conservation strategies are presented. Onthe one hand, some measures should be taken on themanagement side: (i) fishing should be prohibited in theYangtze River, (ii) a solid plan on A. sinensis resourcesconservation should be identified based on scientific criteriafor which research should be completed, and (iii) managementof the water environment in the Yangtze River system shouldbe enhanced. On the other hand, a lot of emphasis should beplaced on studies of the natural population, including theexisting and remaining core natural spawning grounds andhabitats of A. sinensis. Additionlly, cryopreservation ofgametes for gene banking and constructing aritificial spawninggrounds for broodstock management are highly necessary,while also the establishment of closed-cycle systems formaintaining captive broodstock is needed in order to providethe quality control needed for the foundation of sustainablefarming while at the same time serving as a tool for thepreservation of the gene pool of A. sinensis species.IntroductionChinese sturgeon (Acipenser sinensis Gray) is a large andtypically anadromous species, which is mainly distributed inthe Yangtze River system and along the continental shelf areasof the East China Sea and Yellow Sea (YARSG, 1988). It wasalso listed as a Critical Endangered species in the IUCN RedList (IUCN, 2010). In the late 20th century, due to increasedhuman activities, such as hydroelectric projects, overfishing,water pollution, heavy shipping, dredging of navigationchannels and quarrying have altered the river system, blockedthe migration route, changed the spwaning grounds, alteredthe river bed morphology and substrate types of the habitatsfor A. sinensis. Meanwhile, the`se human activities have alsochanged the hydrogeology, and the water quality as well asspatial distribution of natural runoff of the Yangtze River (Huet al., 1985). All of these changes have failed to satisfy theconditions (habitats and hydrologic and water quality) neededfor natural reproduction of A. sinensis (Hu et al., 1992; Yanget al., 2006; Zhang et al., 2007). It was reported that thespawning grounds have been limited to

Summary The authors examined the current status of sturgeon aquaculture in China, including its geographic distribution, an account on farmed species, overall production trends, state of controlled reproduction, seedling output and export. The study is based on a nationwide survey of 125 farms undertaken July and August 2009 together with data from previous studies. The census shows that: (i) the main provinces in increasing order of production are Sichuan (including Chongqing), Beijing, Hubei, Shandong and Hunan, (ii) Acipenser baerii, (and its hybrids) and A. schrenckii are the dominant cultured species, accounting for 95% of the total production, (iii) the production of farmed sturgeon has experienced a steady increase, from 17 424 t in 2006 to 21 000 t in 2009, (iv) the total reserves of captive stocks have continuously increased, reaching at present an estimated 1.22 million individuals, (v) the total supply of fertilized eggs or larvae from farmed broodstocks in China has gone up during the past 3 years, and can now basically meet the domestic demand for farming, while the number of seedlings obtained from the wild and imported from other countries gradually declined, and (vi) since 2006, China has started to export farmed caviar and the exports have been increasing year by year, meanwhile, the number of caviar processing factories has also increased. Moreover, other valueadded products derived from farmed sturgeon (e.g. medical and health products, cosmetics, leather etc.) appeared in recent years on China markets. Corresponding to the sturgeon aquaculture development in China, some additional future aquaculture strategies are discussed: (i) make full use of the resources, (ii) strengthen management strategies and upgrade the culture techniques, (iii) develop and implement labeling systems for good quality control, (iv) foster deep-processing (value added products) in sturgeon farming to widen market options, (v) enhance extensive genetic studies and research on gynogenesis and cryopreservation of gametes for better resource management, (vi) improve the knowledge on early sex-differentiation in sturgeon, and (vii) prepare standards for management of sustainable sturgeon aquaculture. Considering the current progress of sturgeon aquaculture, the prospects of future sturgeon farming are assessed: (i) there will be a potential for considerable aquaculture to serve the caviar market, and farmed caviar may replace wild products, (ii) product diversification will increase and target for export markets, (iii) hatchery operations to produce juveniles from controlled reproduction will completely replace supply from wild and imported resources, and (iv) an industry chain will be gradually established to ensure sustainable sturgeon aquaculture production in China.

Summary When paddlefish, Polyodon spathula, eggs were fertilized with UV irradiated (863 l Wc m )2 ) sperm of Amur sturgeon, Acipenser schrenckii, viable gynogenetic diploid progeny with approximately 120 chromosomes occurred due to spontaneous diploidization of the maternal set of chromosomes (SDM). Distant hybridization of P. spathula eggs by A. schrenckii sperm induced inviable gynogenetic haploid progeny with approximately 60 chromosomes. When eggs gynogenetically activated by heterospecific sperm were heatshocked with 37� C for 2 min at 18 min post-fertilization, a small proportion (7.8%) of viable gynogenetic diploid progeny appeared. The female inheritance of these gynogenetic diploid progeny was verified by chromosome analyses and microsatellite genotyping.

Similar to the pulsar, the magnetic axis and the spin axis of the gamma-ray burst source may not lie on the same line. This may cause a ring-like jet due to collimation of the precessing magnetic axis. We analyze the tail emission from such a jet, and find that it has a shallow decay phase with temporal index equal to -1/2 if the Lorentz factor of the ejecta is not very high. This phase is consistent with the shallow decay phase of some early X-ray afterglow detected by {\it{swift}}. The ring-like jet has a tail cusp with sharp rising and very sharp decay. This effect can provide an explanation for the re-brightening and sharp decay of the X-ray afterglow of GRB 050709., 6 pages, 2 figures. Accepted by ChJAA

A total of 166 cases were divided into 3 groups: group A comprised 55, group B 54 and group C 57 cases. Group A received ivermectin 0.1 mg/kg orally at a single dose, the cure rates were 100%, 3.8% and 50% for ascaris, hookworm and trichuris, infections respectively: group B received ivermectin 0.2 mg/kg orally at a single dose, the corresponding cure rates were 95.5%, 11.8% and 76.5% respectively; group C received pyrantel pamoate 10 mg/kg orally at a single dose, the corresponding cure rates were 95.5%, 29.6% and 31.6% respectively. Although the cure rates were very low for hookworm infection in both group A and B, however, a number of adult worms of Ancylostoma duodenale and Necator americanus were expelled aster medication; It indicates that ivermectin has some effects on these two species of human hookworm. Side effects were mild and transient in all groups.

A chamber filled with salt solution and separated into two compartments by a Teflon partition with a pore of 700 microns diameter was used to investigate the action of aureofuscin, a polyene antibiotics, on a planar lipid bilayer. The pore was covered with a bilayer formed by a N-decane solution of lecithin and cholesterol (20 mg/ml and 5 mg/ml). The electrical property and ionic permeability of the bilayer were studied by using voltage clamp method. Decrease of the bilayer resistance and the channel-like activity could be observed 20 min after the addition of aureofuscin (10-20 micrograms/ml) to one compartment. The existence of a transmembrane voltage and ionic gradient were not necessary for the channel-forming activity of aureofuscin. Discrete current steps were recorded at a concentration of 1.4 micrograms/ml aureofuscin, with a predominant unit conductance of 4-6 pS in a symmetric KCl, solution of 100 mmol/L. By using Goldmann-Hodgkin-Katz voltage equation the ionic selectivity of the channel formed by aureofuscin was estimated by the reversal potential measured in the asymmetrical solution system. The results showed that aureofuscin channels were more permeable to potassium ion than to chloride ion (PK/PCl approximately 5.2). These data may be used to explain the action of aureofuscin on neurotransmitter release and muscle membrane potential in addition to providing some explanation on its curing effect in clinical use.