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Transmission of precise phase coherent optical signals using a VCsEL stabilization system

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Optoelectronics Letters 2019年第3期15卷 200-203页

作者： shukree Wassin george Isoe Andrew Leitch tim Gibbon Centre for Broadband Communication Physics DepartmentNelson Mandela University

To improve the time and frequency reference standards used for radio astronomy and high precision atomic physics applications, we describe a novel stable frequency transmission technique. The approach uses a vertical-cavity surface-emitting laser(VCsEL) based phase correction actuator. Using a frequency mixing process for feedback control, the phase noise induced along the 26 km G.655 optical fibre link was actively reduced. This was achieved by using a 1 310 nm dither controlled VCsEL phase error correction actuator together with the inherent chromatic dispersion properties of the fibre. The technique corrects phase noise and optical signal drift along the fibre at the transmission end. Fractional frequency instabilities across the G.655 fibre link of 4.44×10-12 at 1 s and 4.86×10-14 at 104 s are successfully reported.

关键词： VCsEL Transmission of precise phase coherent optical signals using a VCsEL stabilization system

A new species of smooth skink (squamata： scincidae： scincella) from Cambodia

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Zoological Research 2018年第3期39卷 220-240页

作者： thy Neang somaly Chan Nikolay A. Poyarkov, Jr. Wild Earth Allies Sk. Phnom Penh Thmei Kh. Sen Sok Phnom Penh Cambodia Ministry of Environment Sk. Tonle Bassac Kh. Chamkarmorn Phnom Penh Cambodia Department of Vertebrate Zoology Biological Faculty Lomonosov Moscow State University Moscow 119234 Russia Joint Russian-Vietnamese Tropical Research and Technological Centre Nghia Do Cau Giay Hanoi Vietnam

Based on morphological and genetic evidence we evaluated the taxonomic status of a newly discovered forest-dwelling population of skink （genus scincella） from the Keo selma Wildlife sanctuary, Mondulkiri Province, Cambodia. From phylogenetic analysis of a 668-bp fragment of the mtDNA COl and diagnostic morphological characters we allocate the newly discovered population to the scincella reevesii-s. rufocaudata species complex and describe it as scincella nigrofasciata sp. nov. The new skink species can be distinguished from all other southeast Asian congeners by the following combination of morphological characters： snout-vent length （sVL） 40.0-52.6 mm; relative tail length （TaL/sVL ratio） 1.25-1.94; prefrontals in broad contact; infralabials 6; primary temporals 2; relative forelimb length （FIL/sVL ratio） 0.20-0.22; relative hindlimb length （HIL/sVL ratio） 0.30-0.33; relative forearm length （FoL/sVL ratio） 0.14-0.16; adpressed forelimbs and hind limbs either overlapping （0.4-2.2 mm） or separated （1.9-2.3 mm）; midbody scale rows 32-33, paravertebral scales 69-74, vertebral scales 65-69; dorsal scales between dorsolateral stripes 8; comparatively slender fingers and toes, subdigital lamellae under fourth toe 15-17; dark discontinuous regular dorsal stripes 5-7; distinct black dorsolateral stripes, narrowing to lateral sides and extending to 52%-86% of total tail length. We provide additional information on the holotype of scincella rufocaudata （Darevsky ＆ Nguyen, 1983）, and provide evidence for the species status of scincella rupicola. Our discovery brings the number of scincellaspecies in Cambodia to five and emphasizes the incompleteness of knowledge on the herpetofaunal diversity of this country.

关键词： Mondulkiri Keo seima Wildlifesanctuary Taxonomy mtDNA COl DNA barcoding Phylogenetics

Team Members’ Psychological Contract and Team Performance:the Role of shared Leadership

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Team Members’ Psychological Contract and Team Performance:t...

作者： CHANNAK thy 上海交通大学

学位级别：硕士

Introduction-The study that helps organization discover their employee’s perception and behavior related to a psychological contract（*** 1989;Coyle-shapiro and Parzefall 2008）.Psychological contracts are associated with beliefs of obligation that employees have based upon the exchange agreement between themselves and their foremen（Robinson,Kraatz and Rousseau 1994;*** 1989）.At the mean time,teamwork has increasingly become the great interest of scholars and researchers for its effectiveness in work *** organizations adopt teamwork as a drive to achieve specific organizational ***,leadership behavior such as shared or distributed leadership is considered as the critical factor which could achieve the effectiveness of ***,shared leadership is conceptualized as a more relational process,a shared or distributed phenomenon occurring at different levels and depend on social interactions and networks of influence（Conger and Pearce 2003）.Besides,psychological contract is used to explain the relationship between organizations and employees while shared leadership is associated with the outcome of group performance and improve team’s *** the previous findings,the formation of the psychological contract remains theoretically underdeveloped and receive the limited empirical attention which induces more call for research ***,the shift in organizational leadership has become the focus of many empirical kinds of literature that raised the question what kind of leadership will be appropriate in new team based ***-This research is to provide a new proposed model framework to test the existing concepts of psychological contract and shared leadership by connecting these variables and the consequence of their ***,this study focuses on the psychological contract of team’s *** types of thepsychological contract are investigated as well as team ***,within group process,shared l

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Pharmacological activity,phytochemical analysis and toxicity of methanol extract of Etlingera elatior(torch ginger) flowers

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Asian Pacific Journal of Tropical Medicine 2010年第10期3卷 769-774页

作者： subramanion Jo thy Lachumy sreenivasan sasidharan Velio sumathy Zakaria Zuraini school of Distance Education Universiti Sains MalaysiaMinden 11800Pulau PinangMalaysia Institute for Research in Molecular Medicine(INFORMM) Universiti Sains MalaysiaMinden 11800Pulau PinangMalaysia

Objective:To elucidate its pharmacological activities and medicinal potential of extract of Etlingera elatior（***）.Methods:Phytochemical screening of the flower extract was done to determine the phytochemical in the *** pharmacological study included the determination of antimicrobial activity and minimum inhibitory concentration（MIC） of metabolic flower *** antimicrobial activity of the extract was tested against medically important bacterial,yeast and fungal *** from that,the methanolic extract of *** flower was further tested in vivo toxicity using the brine shrimp lethality ***,the flower extract was qualitatively screened for their free radical scavenging activity by 2,2-diphenyl-1- picrylhydrazyl radical（DPPH） ***:The extract was effective on tested microorganisms and MIC values were in the range of 1.563-50.000 mg/*** brine shrimp lethality test exhibited no significant toxicity(LCsub>50sub>= 2.52 mg/mL) against Artemia *** *** flower extract with high LCsub>50sub> value signified that this plant is not toxic to *** the phytochemical screening of the flower extract revealed the presence of the following compounds: flavonoids,terpenoids,saponin,tannins and carbohydrates whereas,alkaloids,anthraquinone and reducing sugars were *** concentration of the flower extract required for 50% inhibition of DPPH radical scavenging effect(ICsub>50sub>) were 9.14 mg/mL and 8.08 mg/mL for butylated hydroxytoluene 8.08 mg/***:These findings indicate that the extract of *** flower possesses pharmacological properties and potential to develop natural products based pharmaceuticals products.

关键词： Etlingera elatior Pharmacological activity Phytochemical analysis Artemia salina

False codling moth Thaumatotibia leucotreta （Lepidoptera, Tortricidae） larvae are chill-susceptible

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Insect science 2012年第3期19卷 315-328页

作者： Leigh Boardman tim G. Grout John s. Terblanche Department of Conservation Ecology and Entomology Faculty of Agrisciences Stellenbosch University Stellenbosch South Africa Citrus Research International Nelspruit South Africa

This study reports on the low temperature tolerance and cold hardiness of larvae of false codling moth, Thaumatotibia leucotreta. We found that larvae have mean critical thermal minima （lower limits of activity） of 6.7℃ which was influenced by feeding status. The effects of low temperature exposure and duration of exposure on larval survival were assessed and showed that the temperature at which 50% of the population survives is -11.5 ± 0.3℃ after 2 h exposure. The supercooling point （sCP, i.e., freezing temperature） was investigated using a range of cooling rates and under different conditions （feeding and hydration status） and using inoculative freezing treatments （in contact with water or orange juice）. The sCP decreased significantly from -15.6℃ to -17.4℃ after larvae were fasted for 24 h. Twenty-four hour treatments at either high or low relative humidity （95.9% or 2.4%） also significantly decreased sCP to -17.2℃ and -18.2℃ respectively. Inoculative freezing （by water contact） raised sCP from -15.6℃ to -6.8℃ which could have important implications for post-harvest sterilization. Cooling rates did not affect sCP which suggests that there is limited phenotypic plasticity of sCP during the larval life-stage, at least over the short time-scales investigated here. In conclusion, larvae of T. leucotreta are chill-susceptible and die upon freezing. These results are important in understanding this pest＇s response to temperature variation, understanding pest risk status and improving post-harvest sterilization efficacy

关键词： behavior chill injury cold hardiness disinfestations extracellular freezing,lethal limits life-stage

Effect of Baroclinicity on Vortex Axisymmetrization. Part Ⅱ:Baroclinic Basic Vortex

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Advances in Atmospheric sciences 2014年第6期31卷 1267-1278页

作者： Jiayi PENG Melinda s.PENG tim LI Eric HENDRICKs IMsG at Environmental Modeling Center NCEP/NOAA College Park Maryland USA Naval Research Laboratory Monterey California USA Department of Meteorology and IPRC University of Hawaii at Manoa Honolulu Hawaii USA

The effect of baroclinicity on vortex axisymmetrization is examined within a two-layer dynamical *** basic state vortices are constructed with varying degrees of baroclinicity：（i） barotropic,（ii） weak baroclinic,and （iii） strong *** linear and nonlinear evolution of wavenumber-2 baroclinic disturbances are examined in each of the three basic state *** results show that the radial propagating speed of the vortex Rossby wave at the lower level is larger with the stronger baroclinicity,resulting in a faster linear axisymmetrization process in the stronger baroclinic *** is found that the nonlinear axisymmetrization process takes the longest time in the strongest baroclinic vortex among the three different basic vortices due to the weaker kinetic energy transfer from asymmetric to symmetric circulations at the lower level.A major finding in this study is that the same initial asymmetric perturbation can have different effects on symmetric vortices depending on the initial vortex *** numerical weather prediction models,this implies that there exists a sensitivity of the subsequent structural and intensity change solely due to the specification of the initial vertical shear of the tropical cyclone vortex.

关键词： vortex axisymmetrization asymmetry baroclinicity

Effect of Baroclinicity on Vortex Axisymmetrization. Part Ⅰ:Barotropic Basic Vortex

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Advances in Atmospheric sciences 2014年第6期31卷 1256-1266页

作者： Melinda s.PENG Jiayi PENG tim LI Eric HENDRICKs Naval Research Laboratory Monterey California USA IMsG at Environmental Modeling Center NCEP/NOAA College Park Maryland USA Department of Meteorology and IPRC University of Hawaii at Manoa Honolulu Hawaii USA

The barotropic and baroclinic disturbances axisymmetrized by the barotropic basic vortex are examined in an idealized modeling framework consisting of two *** a Wentzel-Kramers-Brillouin approach,the radial propagation of a baroclinic disturbance is shown to be slower than a barotropic disturbance,resulting in a slower linear axisymmetrization for baroclinic *** slower-propagating baroclinic waves also cause more baroclinic asymmetric kinetic energy to be transferred directly to the barotropic symmetric vortex than from barotropic disturbances,resulting in a faster axisymmetrization process in the nonlinear baroclinic wave case than in the nonlinear barotropic wave case.

关键词： vortex axisymmetrization asymmetry baroclinicity

solvable base change and Rankin-selberg convolutions

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science China Mathematics 2017年第1期60卷 99-112页

作者： GILLEsPIE tim Department of Mathematics St. Ambrose University Davenport IA 52803 USA

Let π and π′ be unitary automorphic cuspidal representations of GL_n(A_E) and GL_m(A_F), and let E and F be solvable Galois extensions of Q of degrees ? and ?′, respectively. Using the fact that the automorphic induction and base change maps exist for E and F, and assuming an invariance condition under the actions of the Galois groups, we attach to the pair(π, π′) a Rankin-selberg L-function L(s, π×E,Fπ′) for which we prove a prime number theorem. This gives a method for comparing two representations that could be defined over completely different extensions, and the main results give a measure of how many cuspidal components the two representations π and π′ have in common when automorphically induced down to the rational numbers. The proof uses the structure of the Galois group of the composite extension EF and the character groups attached to the fields via class field theory. The second main theorem also gives an indication of when the base change of π up to the composite extension EF remains cuspidal.

关键词： automorphic L-function base change automorphic induction

Antipredator deception in terrestrial vertebrates

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Current Zoology 2014年第1期60卷 16-25页

作者： tim CARO Department of Wildlife Fish and Conservation Biology and Center of Population Biology University of California Davis CA95616 USA

Abstract Deceptive antipredator defense mechanisms fall into three categories： depriving predators of knowledge of prey＇s presence, providing cues that deceive predators about prey handling, and dishonest signaling. Deceptive defenses in terrestrial vertebrates include aspects of crypsis such as background matching and countershading, visual and acoustic Batesian mimicry, active defenses that make animals seem more difficult to handle such as increase in apparent size and threats, feigning injury and death, distractive behaviours, and aspects of flight. After reviewing these defenses, I attempt a preliminary evaluation of which aspects of antipredator deception are most widespread in amphibians, reptiles, mammals and birds

关键词： Amphibians Birds Defenses Dishonesty Mammals Prey Reptiles