Field margins as rapidly evolving local diversity hotspots for ground beetles (Coleoptera : Carabidae) in northern China

The diversity of carabid assemblages at newly established field margins was compared to the diversity in surrounding fields and woodland habitats at Dongbeiwang village, Beijing. Carabids were sampled using 6 pitfalls per plot at a total of 12 plots in the year 2000. Although sampled only a year after their establishment, field margins harbored the most abundant and diverse carabids assemblages of all sites. More than a quarter of carabid species encountered were furthermore restricted to catches from field margins. Also woodland and fields under rotational wheat/maize cultivation harbored some unique species. Therefore, a short term establishment of field margins is effective in enhancing diversity and abundance of carabids, an important predator group in the agricultural landscape, while only the preservation of a heterogeneous landscape will enable the conservation of the overall species diversity

Vortex formation processes from an oscillating circular cylinder at high Keulegan-Carpenter numbers

Development of vortex patterns around a circular cylinder oscillating in quiescent water is investigated using time-resolved particle image velocimetry. Experiments are performed at Keulegan–Carpenter (KC) numbers between 8 and 36 with Reynolds number kept constant at 2400. Similar to previous studies, three modes of vortex patterns are identified and denoted as modes I, II, and III. The development of vortices in each mode at successive phases of cylinder oscillation is studied in details. The classification of modes is based on the development mechanism of shear layers around the cylinder, the number of vortices shed in each half cycle, and the characteristics of the vortex street. Modes I, II, and III are characterized by one, two, and three (or more) vortices generated, respectively, in each half cycle. The appropriate vortex formation length is applied to explain the dependence of number of vortices formed in each cylinder cycle on KC. Vortex shedding in mode I occurs only on one side of the line of cylinder motion. This mode, which occurs at KC between 8 and 16, is observed to have two submodes with different orientations of the vortex street to the line of cylinder motion. Mode II occurs at KC between 16 and 24. The vortex street extends to both sides of the line of cylinder motion and lies at about 45° to it. At KC>24, vortices are shed behind the moving cylinder similar to the case of a towed cylinder. The limited-length vortex street in this mode III pattern lies along the line of cylinder motion. Each vortex pattern is associated with a typical secondary flow stream, which affects distinct evolution stages of vortices around the cylinder and hence the unique vortex pattern. The development of vortices is found to involve complex vortex interaction involving migration, stretching, and splitting.published_or_final_versio

Fully-Unintegrated Parton Distribution and Fragmentation Functions at Perturbative k_T

We define and study the properties of generalized beam functions (BFs) and fragmenting jet functions (FJFs), which are fully-unintegrated parton distribution functions (PDFs) and fragmentation functions (FFs) for perturbative k_T. We calculate at one loop the coefficients for matching them onto standard PDFs and FFs, correcting previous results for the BFs in the literature. Technical subtleties when measuring transverse momentum in dimensional regularization are clarified, and this enables us to renormalize in momentum space. Generalized BFs describe the distribution in the full four-momentum k_mu of a colliding parton taken out of an initial-state hadron, and therefore characterize the collinear initial-state radiation. We illustrate their importance through a factorization theorem for pp -> l^+ l^- + 0 jets, where the transverse momentum of the lepton pair is measured. Generalized FJFs are relevant for the analysis of semi-inclusive processes where the full momentum of a hadron, fragmenting from a jet with constrained invariant mass, is measured. Their significance is shown for the example of e^+ e^- -> dijet+h, where the perpendicular momentum of the fragmenting hadron with respect to the thrust axis is measured.Comment: Journal versio

Upper Paleocene radiolarians from DSDP Sites 549 and 550, Goban Spur, NE Atlantic

Upper Paleocene-lower Eocene sequences of mainly pelagic sediments in DSDP Sites 549 and 550 of Goban Spur, NE Atlantic, representing time periods of 10 and 6. m.y. respectively, were examined to investigate the biotic response of radiolarians to the PETM. The preservation of radiolarians in the lower Eocene sequences for both sites is poor. Upper Paleocene radiolarian assemblages, representing a time interval of ~59-56. Ma at Site 549 and a much shorter period at Site 550, are generally moderately well-preserved. Fifty-four species were identified. Four species occur significantly earlier in the middle high latitude NE Atlantic than in New Zealand, where the sudden appearance during the PETM has been taken as evidence of global pole-ward migration of warm-water radiolarians. Available model shows that the Goban Spur area should belong to the subpolar surface ocean gyre in the early Paleogene. Thus, our investigation questions the validity of the previously used index species of subtropical warm water masses. High-latitude offshore sections across the P/E boundary with well preserved radiolarians are needed to test the hypothesis of pole-ward migration of warm-water radiolarians during this geologically transient global warming period. © 2011 Elsevier Ltd and Nanjing Institute of Geology and Palaeontology, CAS.postprin

Computational Complexity of interacting electrons and fundamental limitations of Density Functional Theory

One of the central problems in quantum mechanics is to determine the ground state properties of a system of electrons interacting via the Coulomb potential. Since its introduction by Hohenberg, Kohn, and Sham, Density Functional Theory (DFT) has become the most widely used and successful method for simulating systems of interacting electrons, making their original work one of the most cited in physics. In this letter, we show that the field of computational complexity imposes fundamental limitations on DFT, as an efficient description of the associated universal functional would allow to solve any problem in the class QMA (the quantum version of NP) and thus particularly any problem in NP in polynomial time. This follows from the fact that finding the ground state energy of the Hubbard model in an external magnetic field is a hard problem even for a quantum computer, while given the universal functional it can be computed efficiently using DFT. This provides a clear illustration how the field of quantum computing is useful even if quantum computers would never be built.Comment: 8 pages, 3 figures. v2: Version accepted at Nature Physics; differs significantly from v1 (including new title). Includes an extra appendix (not contained in the journal version) on the NP-completeness of Hartree-Fock, which is taken from v

Targeting Btk/Etk of prostate cancer cells by a novel dual inhibitor.

Btk and Etk/BMX are Tec-family non-receptor tyrosine kinases. Btk has previously been reported to be expressed primarily in B cells and has an important role in immune responses and B-cell malignancies. Etk has been shown previously to provide a strong survival and metastasis signal in human prostate cancer cells, and to confer androgen independence and drug resistance. While the role of Etk in prostate carcinogenesis is well established, the functions of Btk in prostate cancer have never been investigated, likely due to the perception that Btk is a hematopoietic, but not epithelial, kinase. Herein, we found that Btk is overexpressed in prostate cancer tissues and prostate cancer cells. The level of Btk in prostate cancer tissues correlates with cancer grades. Knockdown of Btk expression selectively inhibits the growth of prostate cancer cells, but not that of the normal prostate epithelial cells, which express very little Btk. Dual inhibition of Btk and Etk has an additive inhibitory effect on prostate cancer cell growth. To explore Btk and Etk as targets for prostate cancer, we developed a small molecule dual inhibitor of Btk and Etk, CTN06. Treatment of PC3 and other prostate cancer cells, but not immortalized prostate epithelial cells with CTN06 resulted in effective cell killing, accompanied by the attenuation of Btk/Etk signals. The killing effect of CTN06 is more potent than that of commonly used inhibitors against Src, Raf/VEGFR and EGFR. CTN06 induces apoptosis as well as autophagy in human prostate cancer cells, and is a chemo-sensitizer for docetaxel (DTX), a standard of care for metastatic prostate cancer patients. CTN06 also impeded the migration of human prostate cancer cells based on a 'wound healing' assay. The anti-cancer effect of CTN06 was further validated in vivo in a PC3 xenograft mouse model

Ion-beam-induced bending of freestanding amorphous nanowires: The importance of the substrate material and charging

Ion-beam irradiation offers great flexibility and controllability in the construction of freestanding nanostructures with multiple advanced functionalities. Here, we present and discuss the bending of free-standing nanowires, against, towards, and ultimately parallel to a flux of directional ion irradiation. Bending components both along and perpendicular to the incident ion beam were observed, and the bending behavior was found to depend both on the ion beam scanning strategy and on the conductivity of the supporting substrate. This behavior is explained by an ion-irradiation-related electrostatic interaction. Our findings suggest the prospect of exploiting this technique to engineer 3D nanostructures for advanced applications

Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles

High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments