β-diversity in temperate grasslands is driven by stronger environmental filtering of plant species with large genomes

Elucidating mechanisms underlying community assembly and biodiversity patterns is central to ecology and evolution. Genome size (GS) has long been hypothesized to potentially affect species' capacity to tolerate environmental stress and might therefore help drive community assembly. However, its role in driving β-diversity (i.e., spatial variability in species composition) remains unclear. We measured GS for 161 plant species and community composition across 52 sites spanning a 3200-km transect in the temperate grasslands of China. By correlating the turnover of species composition with environmental dissimilarity, we found that resource filtering (i.e., environmental dissimilarity that includes precipitation, and soil nitrogen and phosphorus concentrations) affected β-diversity patterns of large-GS species more than small-GS species. By contrast, geographical distance explained more variation of β-diversity for small-GS than for large-GS species. In a 10-year experiment manipulating levels of water, nitrogen, and phosphorus, adding resources increased plant biomass in species with large GS, suggesting that large-GS species are more sensitive to the changes in resource availability. These findings highlight the role of GS in driving community assembly and predicting species responses to global change

Honeycomb-Patterned Hybrid Films and Their Template Applications via A Tunable Amphiphilic Block Polymer/Inorganic Precursor System

通讯作者地址: Li,L(通讯作者),Xiamen Univ,Coll Mat, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Coll Mat, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 3. Chinese Acad Sci, Shanghai Inst Organ Chem, Shanghai 200032, Peoples R China 电子邮件地址: [email protected], we show a facile and versatile method-prepare highly ordered inorganic patterns on solid substrates by pyrolyzing UV cross-linked polymr/functional. precursor hybrid films. The crosslinked polymer matrix acted as structure-directing agent in a pyrolyzing process, whereas the functional precursor was converted into the skeleton of the micropatterns. The inorganic micropatterns could be further catalytically functionalized to grow CNT and ZnO nanorod arrays by simply changing different functional precursors. This simple technique offers new prospects in the field of micropatterns, nanolithography, and template.National Natural Science Foundation of China,50703032,20974089;Natural Science Foundation of Fujian Province,2009J06029; Ministry of Education of Chin

Meta-analysis of genome-wide association studies in East Asian-ancestry populations identifies four new loci for body mass index

Recent genetic association studies have identified 55 genetic loci associated with obesity or body mass index (BMI). The vast majority, 51 loci, however, were identified in European-ancestry populations. We conducted a meta-analysis of associations between BMI and ∼2.5 million genotyped or imputed single nucleotide polymorphisms among 86 757 individuals of Asian ancestry, followed by in silico and de novo replication among 7488–47 352 additional Asian-ancestry individuals. We identified four novel BMI-associated loci near the KCNQ1 (rs2237892, P = 9.29 × 10−13), ALDH2/MYL2 (rs671, P = 3.40 × 10−11; rs12229654, P = 4.56 × 10−9), ITIH4 (rs2535633, P = 1.77 × 10−10) and NT5C2 (rs11191580, P = 3.83 × 10−8) genes. The association of BMI with rs2237892, rs671 and rs12229654 was significantly stronger among men than among women. Of the 51 BMI-associated loci initially identified in European-ancestry populations, we confirmed eight loci at the genome-wide significance level (P < 5.0 × 10−8) and an additional 14 at P < 1.0 × 10−3 with the same direction of effect as reported previously. Findings from this analysis expand our knowledge of the genetic basis of obesity

A study of bandwidth allocation mechanisms on sonet-ring-based transport networks

A new SONET-based network simulator was designed and implemented to study the performance of different routing mechanisms on transport networks based on the SONET ring architecture. The simulator incorporates some unique features of the SONET technology. Three static routing schemes were evaluated on the simulator at different levels of traffic load. The hop-by-hop routing (HHR) scheme uses the physical network as a fat bit pipe to transport the data traffic from one node to its neighboring node. Utilizing the Digital Cross-connect System in the SONET technology, virtual topology routing (VTR) schemes establish the multiple-hop point-to-point links across a SONET ring in order to reduce overall nodal processing time. The simulation results show that virtual topology routing schemes have advantage of low network latency over the hop-by-hop routing scheme only when the bursty traffic load is well below the network capacity. In medium to high traffic load conditions, increased queuing delay counteracts the reduced overall nodal processing time in the VTR schemes, resulting in high network latency, while the HHR scheme have the advantage of high bandwidth utilization and low packet-drop rates. To overcome the drawbacks of the static routing schemes, dynamic bandwidth-allocation mechanisms combining VTR and HHR principles were suggested. The mechanisms allocate bandwidth dynamically between VTR and HHR regions in response to the changes in traffic patterns on a SONET ring. Both centralized model and distributed model were proposed. For the centralized model, the problem of optimal effective bandwidth allocation on the Unidirectional Path Switched Ring (UPSR) architecture was formulated and a solution based on a Greedy algorithm with cost of 0(n²m + mlogm) was provided for UPSR architecture with n nodes and m flows. A heuristic bandwidth optimization algorithm based on the solution for UPSR was developed and evaluated numerically for Bidirectional Path Switched Ring (BPSR) architecture. The possibilities of extending the heuristic algorithms to other SONET-ring-based architectures were also explored. For the distributed model, a mechanism was proposed to maintain the tension between bandwidth utilization and network latency in local scope rather than in global scope. By resolving problem early and locally, intensive computation of global bandwidth optimization and synchronization of global reconfiguration may be avoided.Science, Faculty ofComputer Science, Department ofGraduat

Syntheses, vibrational and solution studies of niobium(V) and tantalum(V) fluoride fluorosulfates

A one-step metal oxidation/ligand redistribution reaction was developed to synthesize niobium(V) and tantalum(V) fluoride fluorosulfates according to the equation: (5-n)M + nMF₅ + excess S₂0₆F₂ ⇢ 5MF[formula omitted](S0₃F)₅-[formula omitted] Five compounds, Nb₂F₉(S0₃F), NbF₄(S0₃F), NbF₃(S0₃F)₂, TaF₄(S0₃F), and TaF₃(S0₃F)₂, were isolated as colorless viscous liquids in pure form. Nb₂F₉(S0₃F) appears to be unstable, and disproportionates into solid [NbF₅]₄ and liquid NbF₄(S0₃F) on long standing. Ta₂F₉(S0₃F) cannot be synthesized in this manner. The attempted isolation of compounds with higher fluorosulfate content, MF[formula omitted](S0₃F)₅-[formula omitted] (M=Nb, Ta; n<3), was not successful. Raman and infrared spectra of the isolated compounds, MF[formula omitted](S0₃F)₅-[formula omitted] (M=Nb, Ta; n≥3), are interpreted in terms of associated structures with approximately octahedral coordination of niobium or tantalum by fluorides and fluorosulfate groups. Bidentate fluorosulfate groups, presumably bridging, are found in all these derivatives. In NbF₃(S0₃F)₂ and TaF₃(S0₃F)₂ both monodentate and bidentate fluorosulfate groups are found. Bridging fluorines are suggested for liquid Nb₂F₉(S0₉F) and, to a lesser extent, NbF₄(S0₃F) and TaF₄(S0₃F) as well. Tentative assignments of the vibrational bands are discussed. The behavior of the stable compounds, MFn(S0₃F)₅-[formula omitted] (M=Nb, Ta; n=2, 3), in HS0₃F was investigated by conductometric studies. At low Lewis acid concentrations, the results show that TaF₃(S0₃F)₂ is a weak Lewis acid in HS0₃F and that NbF₃(S0₃F)₂, NbF₄(S0₃F) and TaF₄(S0₃F) behave as very weak electrolytes and poor S0₃Fˉ acceptors. Conductivities of these solutions in HS0₃F follow the order: TaF₃(S0₃F)₂ » NbF₃(S0₃F)₂ > TaF₄(S0₃F) > NbF₄(S0₃F) . The general trend previously reported for HS0₃F/SbF₅/S0₃ and HS0₃F/AsF₅/S0₃ systems is valid for HS0₃F/NbF[formula omitted](S0₃F)₅-[formula omitted] and HS0₃F/TaF[formula omitted](S0₃F)₅-[fomula omitted] systems, i.e., the more fluorines replaced by fluorosulfate groups, the stronger the resulting superacid. At high Lewis acid concentrations, viscous and highly conducting liquids are present. For the conductivities of the neat liquids, the following order was observed: NbF₃(S0₃F)₂ > TaF₃(S0₃F)₂ > NbF₄(S0₃F) > TaF₄(S0₃F).Science, Faculty ofChemistry, Department ofGraduat

Superacid studies : syntheses, structures and solution studies of Sb(III) and Sb(V) fluoro fluorosulfato derivatives

The HSO₃F/SbF₅ system (“Magic Acid”) was investigated by high resolution ¹⁹F 1D and 2D NMR (COSY and J-resolved). Twelve fluoro-fluorosulfato-antimonate(V) species were clearly identified and the relative concentrations of these species were estimated based on the integration of the ¹⁹F NMR signals for the HSO₃F/SbF₅ systems with SbF₅ concentration ranging from X[sub SbF₅]=0.000999 to X[sub SbF₅]=0.342. The 1:1 and 1:2 complexes between HSO₃F and SbF₅, [SbF₅(HSO₃F)]⁻ and [Sb₂F₁₀(μ-SO₃F)⁻, were found to be the principal species in the system. Other constituent species including the monomers, [SbF₆]⁻,[SbF₄(SO₃F)₂], [SbF₃(SO₃F)₃]⁻ as well as the dimers, [Sb₂F₁₁], [Sb₂F₉(μ-SO₃F)₂]⁻, and [Sb₂F₈(μ-SO₃F)(SO₃F)₂]⁻, were also found in the HSO₃F/SbF₅ system. Trimers of the type [SbF₅-(μ-SO₃F)-SbF₄-(μ-SO₃F)-SbF₅]⁻ are present in systems with X[sub SbF₅]≥0.0989. All the oligomeric fluoro-fluorosulfato-antimonate(V) species were found to be SO₃F-bridged rather than F-bridged. Based on the relative concentrations of the species in the HSO₃F/SbF₅ system, it appears that solvolysis of SbF₅ in HSO₃F is likely to occur in addition to the ligand redistribution. The byproduct HF reacts with SiO₂ to produce H₂0, which is protonated to give the oxonium ion H₃O⁺, which was observed in ¹H NMR spectra of the system. An oxonium salt [H₃O][Sb₂F₁₁] was crystallized from the HSO₃F/SbF₅ system with high SbF₅ content (x[sub SbF₅]≥0.342). The structure of[H₃O][Sb₂F₁₁] is determined by single crystal X-ray diffraction. It has a very complex structure and the asymmetrical O-H⋅⋅⋅F hydrogen bonds link H₃O⁺ and [Sb₂F₁₁] ions to form a 3-dimension network. Two new Sb(III) compounds, [SbF₂(SO₃F)][sub x] and [SbF(SO₃F)₂][sub x], as well as [Sb(SO₃F)₃][sub x], were prepared and their polymeric structures were determined to high precision by single crystal X-ray diffraction. A detailed comparison for the series [SbF{sub n}(SO₃F){sub 3-n}][sub x] (n = 0, 1, 2, or 3) provides an insight into the complex coordination chemistry of Sb(III) fluoride fluorosulfates. Fluoride functions as an asymmetrical bridging ligand and fluorosulfate functions as an 0-tridentate asymmetrical bridging ligands. The overall coordination number of antimony depends on the available donor sites of the ligands and accordingly increases gradually from six for SbF₃ to nine for [Sb(SO₃F)₃][sub x].The Sb-O and Sb-F interactions in all four compounds span a wide range from normal covalent bonds (1.9∼2.1 Å) to long intermolecular contact (∼ 3.0 Å). In order to obtain structural information on superacid anions, single crystals of CsSO₃F, Cs[H(SO₃F)₂], Cs[Au(SO₃F)₄],Cs₂[Pt(SO₃F)₆],and Cs[Sb(SO₃F)₆] were prepared and their crystal structures were determined by single crystal X-ray diffraction. The structures of the superacid anions are correlated to the weak nucleophilicity of anions and hence the acid strength of the corresponding conjugate superacids. The new superacid anion [Sb(SO₃F)₆]⁻ is highly symmetric and has exceptionally short S-O and S-F bonds at the periphery of the anion, From the structure of the anion, it is suggested that [Sb(SO₃F)₆]⁻ should be very weakly nucleophilic. The corresponding conjugate superacid, the HSO₃F/Sb(SO₃F)₅ system, should be a very strong superacid system.Science, Faculty ofChemistry, Department ofGraduat

Coat proteins of necroviruses target 14-3-3a to subvert MAPKKKα-mediated antiviral immunity in plants.

Mitogen-activated protein kinase (MAPK) cascades play an important role in innate immunity against various pathogens in plants and animals. However, we know very little about the importance of MAPK cascades in plant defense against viral pathogens. Here, we used a positive-strand RNA necrovirus, beet black scorch virus (BBSV), as a model to investigate the relationship between MAPK signaling and virus infection. Our findings showed that BBSV infection activates MAPK signaling, whereas viral coat protein (CP) counteracts MAPKKKα-mediated antiviral defense. CP does not directly target MAPKKKα, instead it competitively interferes with the binding of 14-3-3a to MAPKKKα in a dose-dependent manner. This results in the instability of MAPKKKα and subversion of MAPKKKα-mediated antiviral defense. Considering the conservation of 14-3-3-binding sites in the CPs of diverse plant viruses, we provide evidence that 14-3-3-MAPKKKα defense signaling module is a target of viral effectors in the ongoing arms race of defense and viral counter-defense