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Positive geometry in the diagonal limit of the conformal bootstrap
No full textWe consider the diagonal limit of the conformal bootstrap in arbitrary dimensions and investigate the question if physical theories are given in terms of cyclic polytopes. Recently, it has been pointed out that in d = 1, the geometric understanding of the boot-strap equations for unitary theories leads to cyclic polytopes for which the faces can all be written down and, in principle, the intersection between the unitarity polytope and the crossing plane can be systematically explored. We find that in higher dimensions, the natural structure that emerges, due to the inclusion of spin, is the weighted Minkowski sum of cyclic polytopes. While it can be explicitly shown that for physical theories, the weighted Minkowski sum of cyclic polytopes is not a cyclic polytope, it also turns out that in the large conformal dimension limit it is indeed a cyclic polytope. We write down several analytic formulae in this limit and show that remarkably, in many cases, this works out to be very good approximation even for O(1) conformal dimensions. Furthermore, we initiate a comparison between usual numerics obtained using linear programming and what arises from positive geometry considerations
Studies of Beauty Suppression via Nonprompt D-0 Mesons in Pb-Pb Collisions at root s(NN)=5.02 TeV
No full textThe transverse momentum spectra of D-0 mesons from b hadron decays are measured at midrapidity (vertical bar y vertical bar < 1) in pp and Pb-Pb collisions at a nucleon-nucleon center of mass energy of 5.02 TeV with the CMS detector at the LHC. The D-0 mesons from b hadron decays are distinguished from prompt D-0 mesons by their decay topologies. In Pb-Pb collisions, the B -> D-0 yield is found to be suppressed in the measured p(T) range from 2 to 100 GeV/c as compared to pp collisions. The suppression is weaker than that of prompt D-0 mesons and charged hadrons for p(T) around 10 GeV/c. While theoretical calculations incorporating partonic energy loss in the quark-gluon plasma can successfully describe the measured B -> D-0 suppression at higher p(T), the data show an indication of larger suppression than the model predictions in the range of 2 < p(T) < 5 GeV/c
FSRQ/BL Lac dichotomy as the magnetized advective accretion process around black holes: a unified classification of blazars
No full textThe Fermi blazar observations show a strong correlation between gamma-ray luminosities and spectral indices. BL Lac objects are less luminous with harder spectra than flat-spectrum radio quasars (FSRQs). Interestingly FSRQs are evident to exhibit a Keplerian disc component along with a powerful jet. We compute the jet intrinsic luminosities by beaming corrections determined by different cooling mechanisms. Observed gamma-ray luminosities and spectroscopic measurements of broad emission lines suggest a correlation of the accretion disc luminosity with the jet intrinsic luminosity. Also, theoretical and observational inferences for these jetted sources indicate a signature of hot advective accretion flow and a dynamically dominant magnetic field at the jet footprint. Indeed it is difficult to imagine the powerful jet launching from a geometrically thin Keplerian disc. We propose a magnetized, advective disc-outflow symbiosis with explicit cooling to address a unified classification of blazars by controlling both the mass accretion rate and magnetic field strength. The large-scale strong magnetic fields influence the accretion dynamics, remove angular momentum from the infalling matter, help in the formation of strong outflows/jets, and lead to synchrotron emissions simultaneously. We suggest that the BL Lacs are more optically thin and magnetically dominated than FSRQs at the jet footprint to explain their intrinsic gamma-ray luminosities
Endoplasmic reticulum targeting tumour selective photocytotoxic oxovanadium(iv) complexes having vitamin-B6 and acridinyl moieties (vol 45, pg 783, 2016)
No full textThe authors apologize that incorrect images were presented in Fig. 7(a) and 10 (complex 4, MCF-7 panels d-f ). The concerned images in Fig. 7(a) and 10 of this paper were adapted from Fig. 3(b) and 4, respectively, of the associated communication previously published by the same research group in Chemical Communications (cited as ref. 25 in the original article). The errors in the communication are also being rectified through publication of a correction notice. The images have been reviewed by an independent expert and this correction does not alter the conclusions presented in this Dalton Transactions article. (Figure Presented). The corrected version of Fig. 7(a) and 10(d-f ) are shown here. In addition, Fig. 12 of this Dalton Transactions paper is adapted from Fig. 5 of ref. 25. Data for complexes 1 and 4 in Table 5 and Fig. 6 were also reproduced from Table 1 and Fig. 3a, respectively, of ref. 25. Ref. 25 is given below as ref. 1. The reproduced data in Fig. 6, 7(a), 10, 12 and Table 5 were provided for reader's information however, the authors apologise for not correctly attributing the data and figures to their original source. The authors would like to apologize for these errors and for any inconvenience caused. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers
Temporal population variability in local forest communities has mixed effects on tree species richness across a latitudinal gradient
No full textAmong the local processes that determine species diversity in ecological communities, fluctuation-dependent mechanisms that are mediated by temporal variability in the abundances of species populations have received significant attention. Higher temporal variability in the abundances of species populations can increase the strength of temporal niche partitioning but can also increase the risk of species extinctions, such that the net effect on species coexistence is not clear. We quantified this temporal population variability for tree species in 21 large forest plots and found much greater variability for higher latitude plots with fewer tree species. A fitted mechanistic model showed that among the forest plots, the net effect of temporal population variability on tree species coexistence was usually negative, but sometimes positive or negligible. Therefore, our results suggest that temporal variability in the abundances of species populations has no clear negative or positive contribution to the latitudinal gradient in tree species richness
Dietary and habitat shifts in relation to climate of Neogene Quaternary proboscideans and associated mammals of the Indian subcontinent
No full textSeveral studies have established that African proboscideans shifted their feeding strategies (browsing vs. grazing) in response to climatic and ecological changes. However, similar studies on their Indian relatives are rare. In this regard, we analysed the stable carbon (delta C-13) and oxygen (delta O-18) isotope composition, hypsodonty indices (HI), and lamellae numbers of both newly recovered and existing fossil material (proboscideans and associated mammals) spanning the last similar to 14 Ma. We also obtained intra-tooth delta C-13 and delta O-18 values of selected extant and extinct proboscideans as well as associated mammals to understand any intra- and inter-annual variation in dietary and water intake behaviour, respectively. Our results reveal that Middle Miocene brachydont deinotheres (ex. Deinotherium indicum) and bunodont gomphotheres (ex. Gomphotherium) with few cusp pairs were browsers living in relatively closed forests under moist conditions. By Late Miocene they continued browsing in relatively open forests. Deinotheres in the subcontinent did not survive the Late Miocene climate change that led to drier conditions and the spread of grasslands. The Late Miocene endemic forms Stegolophodon and Stegodon were browsers while the immigrant Choerolophodon was a mixed feeder. However, Pliocene gomphotheres such as bunodont Anancus and brachydont Stegodon adapted themselves to shrinking forests and spreading grasslands; the former sustained on grazing, whereas the latter showed flexibility in its diet ranging from browsing, mixed-feeding to pure grazing. Associated mammals such as rhinoceratids, giraffids, equids, and bovids responded in a similar manner to this climatic and ecological transition across the Late Miocene to Pliocene by shifting their diets accordingly. The Mid-Pliocene hypsodont elephantid immigrant Elephas planifrons, the Early Pleistocene hypsodont immigrant E. hysudricus, and Elephas platycephalus, with multiple lamellae (10-16) were also essentially grazers. Sometime around Middle Pleistocene, the giant elephantid immigrant Palaeoloxodon namadicus, a pure grazer, appeared on the grasslands of the subcontinent, coinciding with a shift in E. hysudricus diet from pure grazing to browsing. E. hysudricus likely gave rise to the extant E. maximus, a mixed feeder with higher contribution of browse to its diet
Surface Motions and Continental Deformation in the Indian Plate and the India-Eurasia Collision Zone
No full textThe collision of the Indian plate with Eurasia has played a major role in controlling the dynamics of central Asia leading to the world's largest continental deformation zone. In order to study the deformation within the Indian plate as well as the India-Eurasia collision zone, we model the lithospheric stress field by calculating the two primary sources of stress, one arising due to topography and shallow lithospheric structure estimated by gravitational potential energy differences and the other arising from basal tractions derived from density-driven mantle convection. We use several tomography models to calculate horizontal tractions using the convection code HC for two radially varying viscosity structures. We also take into account lateral viscosity variations in the lithosphere model arising from stiff cratons, weak plate boundaries, and strength variations due to old and young oceanic lithosphere. We do a quantitative comparison of our predicted deviatoric stresses, strain rates, and plate velocities with surface observables and find that the regional tomography model of Singh et al. (2014) embedded in the global S wave model S40RTS does a remarkable job of fitting the observations of GPS velocities and strain rates as well as intraplate stress field from the World Stress Map
Gemini-Based Lipoplexes Complement the Mitochondrial Phenotype in MFN1-Knockout Mouse Embryonic Fibroblasts
No full textMitochondria form a dynamic network of constantly dividing and fusing organelles. The balance between these antagonistic processes is crucial for normal cellular function and requires the action of specialized proteins. The mitochondrial membrane proteins mitofusin 1 (Mfnl) and mitofusin 2 (Mfn2) are responsible for the fusion of the outer membrane of adjacent mitochondria. Mutations within Mfnl or Mfn2 impair mitochondrial fusion and lead to some severe mitochondrial dysfunctions and mitochondrial diseases (MDs). A characteristic phenotype of cells carrying defective Mfnl or Mfn2 is the presence of a highly fragmented mitochondrial network. Here, we use a biocompatible mixture of lipids, consisting on synthetic gemini cationic lipids (GCLs) and the zwitterionic phospholipid (DOPE), to complex, transport, and deliver intact copies of MFN1 gene into MFN1-Knockout mouse embryonic fibroblasts (MFN1-KO MEFs). We demonstrate that the GCL/DOPE-DNA lipoplexes are able to introduce the intact MFN1 gene into the cells and ectopically produce functional Mfnl. A four-fold increase of the Mfnl levels is necessary to revert the MFN1-KO phenotype and to partially restore a mitochondrial network. This phenotype complementation was correlated with the transfection of GCL/DOPE-MFN1 lipoplexes that exhibited a high proportion of highly packaged hexagonal phase. GCL/DOPE-DNA lipoplexes are formulated as efficient therapeutic agents against MDs
Stabilization of Classical B2H5](-): Structure and Bonding of (Cp*Ta)(2)(B2H5)(mu-H)L-2] (Cp*=eta(5)-C5Me5; L=SCH2S)
No full textThe room-temperature reaction of Cp*TaCl4] with LiBH4.THF followed by addition of S2CPPh3 results in pentahydridodiborate species (Cp*Ta)(2)(mu,eta(2):eta(2)-B2H5)(mu-H)(kappa(2),mu-S2CH2)(2)] (1), a classical B2H5](-) ion stabilized by the binuclear tantalum template. Theoretical studies and bonding analysis established that the unusual stability of B2H5](-) in 1 is mainly due to the stabilization of sp(2)-B center by electron donation from tantalum. Reactions to replace the hydrogens attached to the diborane moiety in 1 with a 2 e {M(CO)(4)} fragment (M=Mo or W) resulted in simple adducts, {(Cp*Ta)(CH2S2)}(2)(B2H5)(H){M(CO)(3)}] (6: M=Mo and 7: M=W), that retained the diborane(5) unit
Simultaneous retrieval of global scale Vegetation Optical Depth, surface roughness, and soil moisture using X-band AMSR-E observations
No full textThe radiative transfer scheme implemented for the retrieval of soil moisture from passive microwaves is a function of scattering, polarization mixing and attenuation effects of soil and vegetation. Theses factors are usually represented by Vegetation Optical Depth (VOD), vegetation scattering albedo, and surface roughness parameter, along with soil moisture. The VOD is the degree to which vegetation attenuates the microwave radiation. It has generally the dominant effect from vegetation, whereas scattering is negligible and close to zero. The surface roughness (which varies in space but not much in time) is until recently, often assumed to be a global constant. In this work, we attempted to simultaneously retrieve the VOD, the surface roughness parameter, and the soil moisture at the global scale using the Level 3 daily 0.25 degrees X-band brightness temperatures of the Advanced Microwave Scanning Radiometer Earth Observing System (AMSR-E) sensor. The methodology, coined as the Simultaneous Parameter Retrieval Algorithm (SPRA), is based on the premise that the vegetation dynamics undergo slower temporal changes than the soil moisture-an assumption, which is successfully used in the past for microwave radiometric retrievals at lower frequencies. Results indicate that the SPRA produces the VOD retrievals with reduced high-frequency noise when compared to the baseline Land Parameter Retrieval Algorithm (LPRM) retrievals. This effect assisted in identifying the influence of precipitation and cropping patterns on the temporal dynamics of the VOD. Good agreement is observed between the mean SPRA VOD and canopy height data (global correlation = 0.75). The spatial patterns of surface roughness parameter agree well with the roughness product (HR map) developed using Soil Moisture Ocean Salinity (SMOS) sensor based data (global correlation = 0.57). Validation of SPRA and LPRM soil moisture products with in-situ observations over the Contiguous United States (CONUS) indicated an improvement in mean ubRMSE with SPRA product (SPRA-0.11 m(3)/m(3) and LPRM-0.18 m(3)/m(3)) and comparable mean Pearson correlations between the two products (SPRA-0.36 and LPRM-0.38). Further, a precipitation based consistency evaluation of SPRA and LPRM soil moisture retrievals indicated better skill of the SPRA product over India