Apex Of Pyramid Research Articles

Supplement to Khan 2012 - Technological enhancements needed in photo-trap approach for forthright use by tiger population managers

2551 The fundamental lesson given to budding Wildlife Managers of 1970s was that if they were sure about the continued existence of a healthy population of predator (tiger) at the apex of the ecological pyramid they may draw a logical conclusion that the herbivore and the vegetative habitat forming the lower strata of the pyramid were also in sound conditions. If correctly implemented the status of large cats can indeed be accurately assessed while it is not within possible reach of such order for herbivores or the vegetation. This is true even today. In the year 1972 the first All India Tiger Census was carried out by pugmark tracking (Choudhury 1970). Thereafter census of tiger has been carried out at intervals and based on the results and experiences of field experts at least 39 areas in India have been identified for conservation of tiger and its habitat. Also in this process, a series of management prescriptions have been implemented because of which tiger still survives in the wild (MOEF-Government of India 2006). ‘Pugmark Tracking’ (Singh 1999, 2000) continued to be the accepted method for studying large cats in India until 2004. It was also used in Bangladesh (MOEF-Bangladesh 2004) and Sri Lanka (Kittle & Watson 2007). There is no disagreement that abundance of large

Selective Growth of Microscale GaN Pyramids on Apex of GaN Pyramids

We report on the growth and characterization of microscale GaN structures selectively grown on the apexes of hexagonal GaN pyramids. SiO2 near the apex of the hexagonal GaN pyramids was removed by an optimized photolithography process and subsequently subjected to selective growth of micro scale GaN structures by metal organic vapor phase epitaxy (MOVPE). The pyramidal GaN microstructures which have semi-polar {11̄01} facets, were formed only on the apexes of lower GaN pyramids. The size of the selectively grown micro GaN structures was easily controlled by the growth time. Reduction of the threading dislocation density was confirmed by transmission electron microscopy (TEM) in the selectively regrown micro GaN structures. However, stacking faults developed near the edge of the SiO2 film because of the roughness and nonuniform thickness of the SiO2 film.

Selective Growth of Microscale GaN Pyramids on Apex of GaN Pyramids

Selective Growth of Microscale GaN Pyramids on Apex of GaN Pyramids

Pnictogen–thiacrown complexes with Pt(ii) and Pd(ii)

Platinum(II) and palladium(II) complexes of the trithiacrown [9]aneS(3) containing a range of Group 15 donors are reviewed. These complexes have the general formula [M([9]aneS(3))(L(2))](n+) where L represents at least one Group 15 donor. Complexes involving pnictogens, with the exception of bismuth, are observed. The complexes generally have an elongated square pyramidal geometry with a long distance interaction to the third sulphur of the [9]aneS(3) which forms the apex of the square pyramid. This axial metal-sulphur distance is quite sensitive to the donor properties of L. Poorer donors such as Sb and As ligands show short axial distances whereas the better N donor ligands show longer distances. Pt(II) complexes of the formula [Pt([9]aneS(3))(EPh(3))(2)](2+) (E = P, As, Sb) show a considerable distortion towards a trigonal bipyramidal geometry due to intramolecular π-π interactions. Over seventy of these types of complexes have been crystallographically characterized and are discussed in this article. Other unique features of the complexes, including NMR spectroscopy, redox chemistry, and electronic spectroscopy, are also discussed.

Immateria Medica: Charmers and their Communities in Newfoundland

This paper offers a typology of charmers in Newfoundland, Canada. The ability to charm may be transmitted, often cross-sex, or may be ascribed by the community and adopted as a role by an individual who falls into the recognized categories of being a posthumous child, or a woman who marries a man who shares her own family name. Seventh sons and priests are ascribed the widest range of healing competency and are at the apex of a conceptual pyramid of power. Material is drawn from fieldwork conducted in 2010 and a review of holdings on charming contained in MUNFLA, the Memorial University Folklore and Language Archive. It is argued that it may be premature to conclude that charmers have lost their healing and social roles in Newfoundland communities and that in the case of wart charming, and blood stopping, the tradition continues.

N'-(3-Eth-oxy-2-oxidobenzyl-idene-κO)-4-methyl-benzohydrazidato-κO,N'](methano-lato-κO)oxidovanadium(V).

The title oxidovanadium(V) complex, [V(C17H16N2O3)(CH3O)O], was obtained by the reaction of 3-eth­oxy-2-hy­droxy­benzaldehyde, 4-methyl­benzohydrazide and vanadyl sulfate in methanol. The VV atom is coordinated by the O,N,O′-tridentate Schiff base ligand, one methano­late O atom and one oxide O atom, forming a distorted VO4N square-pyramidal coordination geometry. The oxide O atom lies at the apex of the square pyramid and the N atom of the ligand and the methano­late O atom are trans. The dihedral angle between the benzene rings of the ligand is 1.8 (3)°.

Synthesis, crystal structure, spectroscopic and photoluminescence studies of manganese(II), cobalt(II), cadmium(II), zinc(II) and copper(II) complexes with a pyrazole derived Schiff base ligand

Varying coordination modes of the Schiff base ligand H 2L [5-methyl-1- H-pyrazole-3-carboxylic acid (1-pyridin-2-yl-ethylidene)-hydrazide] towards different metal centers are reported with the syntheses and characterization of four mononuclear Mn(II), Co(II), Cd(II) and Zn(II) complexes, [Mn(H 2L)(H 2O) 2](ClO 4) 2(MeOH) ( 1), [Co(H 2L)(NCS) 2] ( 2), [Cd(H 2L)(H 2O) 2](ClO 4) 2 ( 3) and [Zn(H 2L)(H 2O) 2](ClO 4) 2 ( 4), and a binuclear Cu(II) complex, [Cu 2(L) 2](ClO 4) 2 ( 5). In the complexes 1– 4 the neutral ligand serves as a 3N,2O donor where the pyridine ring N, two azomethine N and two carbohydrazine oxygen atoms are coordinatively active, leaving the pyrazole-N atoms inactive. In the case of complex 5, each ligand molecule behaves as a 4N,O donor utilizing the pyridine N, one azomethine N, the nitrogen atom proximal to the azomethine of the remaining pendant arm and one pyrazole-N atom to one metal center and the carbohydrazide oxygen atom to the second metal center. The complexes 1– 4 are pentagonal bipyramidal in geometry. In each case, the ligand molecule spans the equatorial plane while the apical positions are occupied by water molecules in 1, 3 and 4 and two N bonded thiocyanate ions in 2. In complex 5, the two Cu(II) centers have almost square pyramidal geometry ( τ = 0.05 for Cu1 and 0.013 for Cu2). Four N atoms from a ligand molecule form the basal plane and the carbohydrazide oxygen atom of a second ligand molecule sits in the apex of the square pyramid. All the complexes have been X-ray crystallographically characterized. The Zn(II) and Cd(II) complexes show considerable fluorescence emission while the remaining complexes and the ligand molecule are fluorescent silent.

Modeling of Fabric Impact With High Speed Imaging and Nickel-Chromium Wires Validation

Ballistic tests were performed on single-yarn, single-layer and ten-layer targets of Kevlar® KM2 (600 and 850 denier), Dyneema® SK-65 and PBO® (500 denier). The objective was to develop data for validation of numerical models so, multiple diagnostic techniques were used: (1) ultra-high speed photography, (2) high-speed video and (3) nickel-chromium wire technique. These techniques allowed thorough validation of the numerical models through five different paths. The first validation set was at the yarn level, where the transverse wave propagation obtained with analytical and numerical simulations was compared to that obtained in the experiments. The second validation path was at the single-layer level: the propagation of the pyramidal wave observed with the high speed camera was compared to the numerical simulations. The third validation consisted of comparing, for the targets with ten layers, the pyramid apex and diagonal positions from tests and simulations. The fourth validation, which is probably the most relevant, consisted of comparing the numerical and experimental ballistic limits. Finally for the fifth validation set, nickel-chromium wires were used to record electronically the waves propagating in the fabrics. It is shown that for the three materials the waves recorded during the tests match well the waves predicted by the numerical model.

Evidence that Aurora B is implicated in spindle checkpoint signalling independently of error correction

Fidelity of chromosome segregation is ensured by a tension-dependent error correction system that prevents stabilization of incorrect chromosome-microtubule attachments. Unattached or incorrectly attached chromosomes also activate the spindle assembly checkpoint, thus delaying mitotic exit until all chromosomes are bioriented. The Aurora B kinase is widely recognized as a component of error correction. Conversely, its role in the checkpoint is controversial. Here, we report an analysis of the role of Aurora B in the spindle checkpoint under conditions believed to uncouple the effects of Aurora B inhibition on the checkpoint from those on error correction. Partial inhibition of several checkpoint and kinetochore components, including Mps1 and Ndc80, strongly synergizes with inhibition of Aurora B activity and dramatically affects the ability of cells to arrest in mitosis in the presence of spindle poisons. Thus, Aurora B might contribute to spindle checkpoint signalling independently of error correction. Our results support a model in which Aurora B is at the apex of a signalling pyramid whose sensory apparatus promotes the concomitant activation of error correction and checkpoint signalling pathways.

Hydrogen bonded networks and a self-assembled 1D water cluster in nickel(II) and copper(II)-orotate complexes

Three Ni(II) and Cu(II)-orotate complexes with 1,3-propanediamine (pen) and N-methylethylenediamine (nmen), [Ni(HOr)(H 2O) 2(pen)] ( 1), [Cu 2(μ-HOr) 2(pen) 2] (2) and {[Cu(μ-HOr)(nmen)]·3H 2O} n ( 3) (H 3Or = orotic acid) have been synthesized and characterized by thermal analysis, IR spectroscopy and single crystal X-ray diffraction techniques. In complex 1, the Ni(II) ion has a distorted octahedral geometry. The hydrogen bonds play an important role in the formation of the 3D polymeric structure of complex 1. The carboxylate groups interact with NH 2 groups of pen ligands, and HOr ligands are mutually hydrogen bonded to each other through the pyrimidine N and exocyclic O atoms, giving rise to R 2 2 ( 12 ) and R 2 2 ( 8 ) ring motives, respectively. Complex 2 consists of dimeric [Cu 2( μ-HOr) 2(pen) 2] units in which the Cu(II) ions have square pyramidal coordination geometries with bridging oxygen atoms at the pyramid apex. The HOr ligands, linked by N–H···O hydrogen bonds, constitute centrosymmetric R 2 2 ( 8 ) rings through the plane (1 0 1). The hydrogen bonds between pen and HOr ligands result in R 2 2 ( 8 ) rings centered at ( n + 1, 0, 1/2) ( n = zero or integer). Complex 3 is a 1D coordination polymer, in which the orotate moiety acts as a bridging ligand in the structure. The [Cu(HOr)(nmen)] units are linked by carboxylate oxygen atoms of HOr, which result in a zigzag chain structure along the a axis. Two adjacent 1D coordination polymers are connected through π···π interactions. The lattice water molecules, forming a 1D water cluster, function as a glue to form a 3D supramolecular network through extended hydrogen bonding.

Free Standing AlN Single Crystal Grown on Pre-Patterned and <i>In Situ</i> Patterned 4H-SiC Substrates

Free standing AlN wafers were grown on pre-patterned and in situ patterned 4H-SiC substrates by a physical vapor transport method. It is based on the coalescence of AlN microrods, which evolve from the apex of SiC pyramids grown on the SiC substrate during a temperature ramp up for in situ patterned substrate and SiC pyramids formed by reactive ion etching (RIE). This process yields stress-free (according XRD and Raman results) AlN single crystals with a thickness up to 400 µm and low dislocation density.

Bis(μ-5-hydroxy-2-{[2-(N-phenylthiocarbamoyl)hydrazin-1-ylidene]methyl}phenolato)bis[chloridozinc(II)]N,N-dimethylformamide tetrasolvate

In the dinuclear title compound, [Zn2(C14H12N3O2S)2Cl2]·4C3H7NO, the two monodeprotonated Schiff base ligands N,O,S:O-chelate to Zn atoms. The formally negatively charged O atom involved in chelation also serves as a bridge. The O, O′, N and S atoms comprise a square, and the Cl atom the apex of a square pyramid surrounding each metal atom. The solvate dimethyl­formamide mol­ecules, one of which is disordered over two positions in a 3:1 ratio, are hydrogen bonded to the dinuclear mol­ecule.

An integrated data management and video system for sampling aquatic benthos

Remote video systems can be expensive, slow to deploy and the data recorded may not be available until the system has been retrieved. To overcome these issues, a rapid, non-destructive and cost-effective remote video and data management system was developed to record benthic habitats in Shark Bay, Western Australia. This system comprises a downward-oriented video camera, linked to a laptop computer, attached to the apex of a stainless steel pyramid to film a 1-m2 area of benthos. The video image of the substratum, spatial coordinates, depth and temperature are recorded in a database at the time of deployment. A web interface was developed to manage the database and examine the video images to determine the percentage cover of seagrass, sponge type (conical/non-conical) and the total number of sponges in the quadrat. Using this system, 1380 video quadrats were collected from a study area of ∼248 km2, ranging in water depth from 2 m to 16 m. An average of 16.4 (±1.3 s.e.) samples was recorded every hour during 15 days. This system could be modified to quantify substratum components at a greater taxonomic resolution or to record details of the mobile fauna.

Cu(I), Ag(I) complexes containing (η 5-cyclopentadienyl) [η 5-1-(diphenylphosphino) cyclopentadienyl] cobaltocenium

{Cu4Br5[(η 5-C5H4PPh2)(η 5-C5H5)Co]4}[PF6]3, [(η 5-C5H4PPh2)(η 5-C5H5)Co]+ = ((η 5-cyclopentadienyl)[η 5-1-(diphenylphosphino) cyclopentadienyl] cobaltocenium) and {Ag(NO3)(CH3COCH3)[(η 5-C5H4PPh2)(η 5-C5H5)Co]} n [PF6] n have been synthesized and characterized by elemental analyses, infrared spectroscopy, X-ray diffraction techniques, and by cyclic voltammetry. {Cu4Br5[(η 5-C5H4PPh2)(η 5-C5H5)Co]4}[PF6]3 contains four coplanar copper atoms bridged by four μ-Br and one central μ 4-Br occupying the apex of a square pyramid, and {Ag(NO3)(CH3COCH3)[(η 5-C5H4PPh2)(η 5-C5H5)Co]} n [PF6] n affording a 1-D coordination zigzag polymer.

Microfabricated magnetic bead polydimethylsiloxane microarrays

Bead-based technologies are an attractive alternative to classical microarrays due to the high surface area of the beads which enables the immobilization of large numbers of probe molecules leading to increased kinetics and improved signal/noise ratios. A simple, versatile and inexpensive method for the fabrication of magnetic bead arrays is presented. The beads are first assembled into silicon pyramidal wells that have been fabricated by established microfabrication techniques and then mounted onto the apex of PDMS pyramids that replicate the silicon substrates by replica moulding. The bead arrays were used to detect oligonucleotide target sequences for the pathogenic avian H5N1 flu virus and results indicated that superior signal/noise ratios could be achieved compared to those from a classical microarray format.

Superoxidedismutase-mimetic copper(II) complexes containing saccharinate and 4-aminopyridine/4-cyanopyridine

Two copper(II) complexes, [Cu(sac) 2(4-cypy) 2(H 2O)], 1 and [Cu(sac) 2(4-Ampy) 2(H 2O)], 2 (4-cypy: 4-cyanopyridine; 4-Ampy: 4-aminopyridine) were prepared. Physicochemical properties of the complexes were studied by spectroscopic (solution UV–vis, diffuse reflectance and IR) techniques. Structural X-ray diffraction data could be obtained only for [Cu(sac) 2(4-cypy) 2(H 2O)] that it crystallized in the tetragonal space group P4cc with a= b=15.313(1), c=13.240(1) Å, and Z=4 molecules per unit cell. The complex was cited on a crystallographic C 2-axis with the Cu(II) ion in a square–pyramidal environment, coordinated at the pyramid basis to the nitrogen atom of two saccharine anions [d(Cu–N)=2.011(3) Å] and the pyridine N-atom of two 4-cyanopyridine ligands [d(Cu–N)=2.038(4) Å]. The coordination was completed by a water molecule at the pyramid apex [d(Cu–Ow)=2.189(5) Å]. Elemental and spectroscopic analyses revealed an O-saccharinate coordination mode for complex 2 and a square–pyramidal structure. Only complex 2 retained its structure in methanolic solution. However, both complexes were able to catalyze the dismutation of superoxide anion (O 2 −) (pH 7.5) at micromolar concentrations. Therefore, these complexes behaved as useful SOD-mimetic compounds.

Modelling spiral growth at dislocations and determination of critical step lengths from pyramid geometries on calcite {} surfaces

To visualise the morphologic changes of a growing spiral pyramid, a mathematical model was developed and implemented in an algorithm that can loop through the sequential time-frames in a growth sequence. The algorithm simulates growth of spiral pyramids with geometries reflecting variation in the step velocity ratio and critical lengths of inequivalent steps. We have developed a new mathematical model that implements a set of equations describing the relationship between time-dependent change of step length and orientation around dislocation sources. These step length relationships can be used for extracting the critical step lengths that restrict step growth at dislocations. This allows determination of the critical thermodynamic parameters from post-growth AFM images that do not rely on real-time AFM fluid-flow experiments. The model was tested on experimental results obtained from calcite {101¯4} surfaces. A shift in pyramid apex geometry resulting from velocity anisotropy for the obtuse and acute steps was observed for pyramids grown from solutions of variable Ca2+ to CO32− activity ratio. Relative step velocity and pyramid apex angle were correlated with activity ratio. AFM images of rhombic spiral pyramids on calcite surfaces were used for measuring the length of sequential steps for the four step orientations. Step length plots show the same trend in the experimental data as was predicted by the theoretical model. Critical step lengths were determined using linear regression analysis of the experimental results. The step edge energy was calculated to be 3.6 · 10−19 J nm−1 for obtuse step edges and 1.3 · 10−19 J nm−1 for acute edges. These values are consistent with previous experimental and computational studies.

Conductive diamond tips with sub‐nanometer electrical resolution for characterization of nanoelectronics device structures

AbstractOver the past decade, boron‐doped diamond tips have become the ultimate choice for electrically characterizing microelectronics devices using scanning probe methods such as scanning spreading resistance microscopy (SSRM). Although nanometer‐scale electrical resolution has been demonstrated, the development of a reliable probe process remained a challenge. Therefore, we did develop in this work solid diamond tips with sub‐nanometer electrical resolution and integrated them into metal cantilevers using a peel‐off approach. It is shown that the ultra‐high tip resolution is achieved by diamond nanocrystals protruding from the apex of the diamond pyramid. The yield for sub‐nanometer probes is 20–30% in air and 40–60% in vacuum. This paper describes the fabrication scheme, discusses probe characterization, and shows SSRM measurements obtained with these probes. Our probes are routinely used for SSRM measurements and current efforts are focusing on increasing the yield for sub‐nanometer tips further.

Single-laser, one beam, tetrahedral magneto-optical trap

We have realized a 4-beam pyramidal magneto-optical trap ideally suited for future microfabrication. Three mirrors split and steer a single incoming beam into a tripod of reflected beams, allowing trapping in the four-beam overlap volume. We discuss the influence of mirror angle on cooling and trapping, finding optimum efficiency in a tetrahedral configuration. We demonstrate the technique using an ex-vacuo mirror system to illustrate the previously inaccessible supra-plane pyramid MOT configuration. Unlike standard pyramidal MOTs both the pyramid apex and its mirror angle are non-critical and our MOT offers improved molasses free from atomic shadows in the laser beams. The MOT scheme naturally extends to a 2-beam refractive version with high optical access. For quantum gas experiments, the mirror system could also be used for a stable 3D tetrahedral optical lattice.

The Penal State in an Age of Crisis

As a rule, crime and social protest rise in periods of economic crisis in capitalist society. During times of economic and social instability, the well-to-do become increasingly fearful of the general population, more disposed to adopt harsh measures to safeguard their positions at the apex of the social pyramid. The slowdown in the economic growth rate of U.S. capitalism beginning in the late 1960s and early 1970s—converging with the emergence of radical social protest around the same period—was accompanied by a rapid rise in public safety spending as a share of civilian government expenditures. So significant was this shift that we can speak of a crowding out of welfare state spending (health, education, social services) by penal state spending (law enforcement, courts, and prisons) in the United States during the last third of a century.This article can also be found at the Monthly Review website, where most recent articles are published in full.Click here to purchase a PDF version of this article at the Monthly Review website.