Multiple Island Chains in Primary Resonances.

We analyse the dynamics of a relativistic particle moving in a uniform magnetic field and perturbed by a stationary electrostatic wave. We show that a pulsed wave produces an infinite number of perturbing terms with the same winding number. The perturbation coupling alters the number of island chains as a function of the parameters of the wave. We also observe that the number of chains in is always even if the number of islands in each chain is odd.

Tinamous and moa flock together : mitochondrial genome sequence analysis reveals independent losses of flight among ratites

Ratites are large, flightless birds and include the ostrich, rheas, kiwi, emu, and cassowaries, along with extinct members, such as moa and elephant birds. Previous phylogenetic analyses of complete mitochondrial genome sequences have reinforced the traditional belief that ratites are monophyletic and tinamous are their sister group. However, in these studies ratite monophyly was enforced in the analyses that modeled rate heterogeneity among variable sites. Relaxing this topological constraint results in strong support for the tinamous (which fly) nesting within ratites. Furthermore, upon reducing base compositional bias and partitioning models of sequence evolution among protein codon positions and RNA structures, the tinamou–moa clade grouped with kiwi, emu, and cassowaries to the exclusion of the successively more divergent rheas and ostrich. These relationships are consistent with recent results from a large nuclear data set, whereas our strongly supported finding of a tinamou–moa grouping further resolves palaeognath phylogeny. We infer flight to have been lost among ratites multiple times in temporally close association with the Cretaceous–Tertiary extinction event. This circumvents requirements for transient microcontinents and island chains to explain discordance between ratite phylogeny and patterns of continental breakup. Ostriches may have dispersed to Africa from Eurasia, putting in question the status of ratites as an iconic Gondwanan relict taxon. [Base composition; flightless; Gondwana; mitochondrial genome; Palaeognathae; phylogeny; ratites.]

Structural synthesis by transformation of binary chains Strukturelle synthese durch umwandlung binaerer ketten

The paper presents a general method of structural synthesis which can be used to derive all possible simple- and multiple-jointed chains of positive, zero or negative degree-of-freedom. In this method all possible chains with N links and F degrees-of-freedom are derived by the transformation of the corresponding “binary chains” with N binary links and F degrees-of-freedom. The method is illustrated by applying to the case of chains with degrees-of-freedom 1,2,0 and −1.

Mechanical and thermal structure of a cylindrical plume in the earth's mantle

A mantle plume is understood as a hot, narrow, upwelling flow in the earth's mantle and accompanied by an efficient transfer of mass and energy from deep to upper layer of the earth. The cylindrical plume in earth's mantle plays an important role in explaining the origin of the surface hot spots and linear island chains. From the basic hydrodynamical equations, the detailed mechanical and thermal structure of a cylindrical plume of Newtouian fluids with temperature and pressure-dependent viscosity are given in the present paper. For two sets of rheological parameters the radial profiles of upward velocity, temperature and viscosity in the plume and radiuses of the plume at various depths have been calculated.

Topology of toroidal helical fields in non-circular cross-sectional tokamaks

The ordinary differential magnetic field line equations are solved numerically; the tokamak magnetic structure is studied on Hefei Tokamak-7 Upgrade (HT-7U) when the equilibrium field with a monotonic q-profile is perturbed by a helical magnetic field. We find that a single mode (m, n) helical perturbation can cause the formation of islands on rational surfaces with q = m/n and q = (m +/- 1, +/- 2, +/- 3,...)/n due to the toroidicity and plasma shape (i.e. elongation and triangularity), while there are many undestroyed magnetic surfaces called Kolmogorov-Arnold-Moser (KAM) barriers on irrational surfaces. The islands on the same rational surface do not have the same size. When the ratio between the perturbing magnetic field B-r(r) and the toroidal magnetic field amplitude B(phi)0 is large enough, the magnetic island chains on different rational surfaces will overlap and chaotic orbits appear in the overlapping area, and the magnetic field becomes stochastic. It is remarkable that the stochastic layer appears first in the plasma edge region.

A novel method for positioning of InAs islands on GaAs(110)

A novel method for positioning of InAs islands on GaAs (110) by cleaved edge overgrowth is reported. The first growth sample contains strained InxGa1-xAs/GaAs superlattice (SL) of varying indium fraction, which acts as a strain nanopattern for the cleaved-edge overgrowth. Atoms incident on the cleaved edge will preferentially migrate to InGaAs regions where favorable bonding sites are available. By this method InAs island chains with lateral periodicity defined by the thickness of InGaAs and GaAs of SL have been realized by molecular beam epitaxy (MBE). They are observed by means of atomic force microscopy (AFM). The strain nanopattern's effect is studied by the different indium fraction of SL and MBE growth conditions. (c) 2005 Elsevier B.V. All rights reserved.

Interference of robust tori on the resonance overlap

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The defocusing mechanism of isochronous resonances

We present a numerical study concerning the defocusing mechanism of isochronous resonance island chains in the presence of two permanent robust tori. The process is initialized and concluded through bifurcations of fixed points located on the robust tori. Our approach is based on a Hamiltonian system derived from the resonant normal form. Choosing a convenient parameter in this system, we are able to depict a comprehensive analysis of the dynamics of the problem. (c) 2004 Elsevier B.V. All rights reserved.

Effective transport barriers in nontwist systems

In fluids and plasmas with zonal flow reversed shear, a peculiar kind of transport barrier appears in the shearless region, one that is associated with a proper route of transition to chaos. These barriers have been identified in symplectic nontwist maps that model such zonal flows. We use the so-called standard nontwist map, a paradigmatic example of nontwist systems, to analyze the parameter dependence of the transport through a broken shearless barrier. On varying a proper control parameter, we identify the onset of structures with high stickiness that give rise to an effective barrier near the broken shearless curve. Moreover, we show how these stickiness structures, and the concomitant transport reduction in the shearless region, are determined by a homoclinic tangle of the remaining dominant twin island chains. We use the finite-time rotation number, a recently proposed diagnostic, to identify transport barriers that separate different regions of stickiness. The identified barriers are comparable to those obtained by using finite-time Lyapunov exponents.

Establishment and expansion of Lake Malawi rock fish populations after a dramatic Late Pleistocene lake level rise

Major environmental events that fragment populations among multiple island habitats have potential to drive large-scale episodes of speciation and adaptive radiation. A recent palaeolimnological study of sediment cores indicated that Lake Malawi underwent major climate-driven desiccation events 75 000-135 000 years ago that lowered the water level to at least 580 m below the present state and severely reduced surface area. After this period, lake levels rose and stabilized, creating multiple discontinuous littoral rocky habitats. Here, we present evidence supporting the hypothesis that establishment and expansion of isolated philopatric rock cichlid populations occurred after this rise and stabilization of lake level. We studied the Pseudotropheus (Maylandia) species complex, a group with both allopatric and sympatric populations that differ in male nuptial colour traits and tend to mate assortatively. Using coalescent analyses based on mitochondrial DNA, we found evidence that populations throughout the lake started to expand and accumulate genetic diversity after the lake level rise. Moreover, most haplotypes were geographically restricted, and the greatest genetic similarities were typically among sympatric or neighbouring populations. This is indicative of limited dispersal and establishment of assortative mating among populations following the lake level rise. Together, this evidence is compatible with a single large-scale environmental event being central to evolution of spatial patterns of genetic and species diversity in P. (Maylandia) and perhaps other Lake Malawi rock cichlids. Equivalent climate-driven pulses of habitat formation and fragmentation may similarly have contributed to observed rapid and punctuated cladogenesis in other adaptive radiations.

Linear sedimentation rates and approximate mass accumulation rates at DSDP Site 61-462

A 560-meter-thick sequence of Cenomanian through Pleistocene sediments cored at DSDP Site 462 in the Nauru Basin overlies a 500-meter-thick complex unit of altered basalt flows, diabase sills, and thin intercalated volcaniclastic sediments. The Upper Cretaceous and Cenozoic sediments contain a high proportion of calcareous fossils, although the site has apparently been below the calcite compensation depth (CCD) from the late Mesozoic to the Pleistocene. This fact and the contemporaneous fluctuations of the calcite and opal accumulation rates suggest an irregular influx of displaced pelagic sediments from the shallow margins of the basin to its center, resulting in unusually high overall sedimentation rates for such a deep (5190 m) site. Shallow-water benthic fossils and planktonic foraminifers both occur as reworked materials, but usually are not found in the same intervals of the sediment section. We interpret this as recording separate erosional interludes in the shallow-water and intermediate-water regimes. Lower and upper Cenozoic hiatuses also are believed to have resulted from mid-water events. High accumulation rates of volcanogenic material during Santonian time suggest a corresponding significant volcanic episode. The coincidence of increased carbonate accumulation rates during the Campanian and displacement of shallow-water fossils during the late Campanian-early Maestrichtian with the volcanic event implies that this early event resulted in formation of the island chains around the Nauru Basin, which then served as platforms for initial carbonate deposition.

Molecular evidence for an African origin of the Hawaiian endemic Hesperomannia (Asteraceae)

Identification of the progenitors of plants endemic to oceanic islands often is complicated by extreme morphological divergence between island and continental taxa. This is especially true for the Hawaiian Islands, which are 3,900 km from any continental source. We examine the origin of Hesperomannia, a genus of three species endemic to Hawaii that always have been placed in the tribe Mutisieae of the sunflower family. Phylogenetic analyses of representatives from all tribes in this family using the chloroplast gene ndhF (where ndhF is the ND5 protein of chloroplast NADH dehydrogenase) indicate that Hesperomannia belongs to the tribe Vernonieae. Phylogenetic comparisons within the Vernonieae using sequences of both ndhF and the internal transcribed spacer regions of nuclear ribosomal DNA reveal that Hesperomannia is sister to African species of Vernonia. Long-distance dispersal northeastward from Africa to southeast Asia and across the many Pacific Ocean island chains is the most likely explanation for this unusual biogeographic connection. The 17- to 26-million-year divergence time between African Vernonia and Hesperomannia estimated by the DNA sequences predates the age of the eight existing Hawaiian Islands. These estimates are consistent with an hypothesis that the progenitor of Hesperomannia arrived at one of the low islands of the Hawaiian-Emperor chain between the late Oligocene and mid-Miocene when these islands were above sea level. Subsequent to its arrival the southeast Pacific island chains served as steppingstones for dispersal to the existing Hawaiian Islands.

Lithology and approximate sub-bottom depths and ages of the transition of soft to firm ooze and of firm ooze to chalk at DSDP Leg 89 and 90 Sites

Leg 90 recovered approximately 3705 m of core at eight sites lying at middle bathyal depths (1000-2200 m) (Sites 587 to 594) in a traverse from subtropical to subantarctic latitudes in the southwest Pacific region, chiefly on Lord Howe Rise in the Tasman Sea. This chapter summarizes some preliminary lithostratigraphic results of the leg and includes data from Site 586, drilled during DSDP Leg 89 on the Ontong-Java Plateau that forms the northern equatorial point of the latitudinal traverse. The lithofacies consist almost exclusively of continuous sections of very pure (>95% CaCO3) pelagic calcareous sediment, typically foraminifer-bearing nannofossil ooze (or chalk) and nannofossil ooze (or chalk), which is mainly of Neogene age but extends back into the Eocene at Sites 588, 592, and 593. Only at Site 594 off southeastern New Zealand is there local development of hemipelagic sediments and several late Neogene unconformities. Increased contents of foraminifers in Leg 90 sediments, notably in the Quaternary interval, correspond to periods of enhanced winnowing by bottom currents. Significant changes in the rates of sediment accumulation and in the character and intensity of sediment bioturbation within and between sites probably reflect changes in calcareous biogenic productivity as a result of fundamental paleoceanographic events in the region during the Neogene. Burial lithification is expressed by a decrease in sediment porosity from about 70 to 45% with depth. Concomitantly, microfossil preservation slowly deteriorates as a result of selective dissolution or recrystallization of some skeletons and the progressive appearance of secondary calcite overgrowths, first about discoasters and sphenoliths, and ultimately on portions of coccoliths. The ooze/chalk transition occurs at about 270 m sub-bottom depth at each of the northern sites (Sites 586 to 592) but is delayed until about twice this depth at the two southern sites (Sites 593 and 594). A possible explanation for this difference between geographic areas is the paucity of discoasters and sphenoliths at the southern sites; these nannofossil elements provide ideal nucleation sites for calcite overgrowths. Toward the bottom of some holes, dissolution seams and flasers appear in recrystallized chalks. The very minor terrigenous fraction of the sediment consists of silt- through clay-sized quartz, feldspar, mica, and clay minerals (smectite, illite, kaolinite, and chlorite), supplied as eolian dust from the Australian continent and by wind and ocean currents from erosion on South Island, New Zealand. Changes in the mass accumulation rates of terrigenous sediment and in clay mineral assemblages through time are related to various external controls, such as the continued northward drift of the Indo-Australian Plate, the development of Antarctic ice sheets, the increased desertification of the Australian continent after 14 m.y. ago, and the progressive increase in tectonic relief of New Zealand through the late Cenozoic. Disseminated glass shards and (altered) tephra layers occur in Leg 90 cores. They were derived from major silicic eruptions in North Island, New Zealand, and from basic to intermediate explosive volcanism along the Melanesian island chains. The tephrostratigraphic record suggests episodes of increased volcanicity in the southwest Pacific centered near 17, 13, 10, 5 and 1 m.y. ago, especially in the middle and early late Miocene. In addition, submarine basaltic volcanism was widespread in the southeast Tasman Sea around the Eocene/Oligocene boundary, possibly related to the propagation of the Southeast Indian Ridge through western New Zealand as a continental rift system.

The corporatization of community pharmacy:implications for service provision, the public health function, and pharmacy's claims to professional status in the United Kingdom

Background Pharmacy has experienced both incomplete professionalization and deprofessionalization. Since the late 1970s, a concerted attempt has been made to re-professionalize pharmacy in the United Kingdom (UK) through role extension—a key feature of which has been a drive for greater pharmacy involvement in public health. However, the continual corporatization of the UK community pharmacy sector may reduce the professional autonomy of pharmacists and may threaten to constrain attempts at reprofessionalization. Objectives The objectives of the research: to examine the public health activities of community pharmacists in the UK; to explore the attitudes of community pharmacists toward recent relevant UK policy and barriers to the development of their public health function; and, to investigate associations between activity, attitudes, and the type of community pharmacy worked in (eg, supermarket, chain, independent). Methods A self-completion postal questionnaire was sent to a random sample of practicing community pharmacists, stratified for country and sex, within Great Britain (n = 1998), with a follow-up to nonresponders 4 weeks later. Data were analyzed using SPSS (SPSS Inc., Chicago, IL, USA) (v12.0). A final response rate of 51% (n = 1023/1998) was achieved. Results The level of provision of emergency hormonal contraception on a patient group direction, supervised administration of medicines, and needle-exchange schemes was lower in supermarket pharmacies than in the other types of pharmacy. Respondents believed that supermarkets and the major multiple pharmacy chains held an advantageous position in terms of attracting financing for service development despite suggesting that the premises of such pharmacies may not be the most suitable for the provision of such services. Conclusions A mixed market in community pharmacy may be required to maintain a comprehensive range of pharmacy-based public health services and provide maximum benefit to all patients. Longitudinal monitoring is recommended to ensure that service provision is adequate across the pharmacy network.

An island called India: phylogenetic patterns across multiple taxonomic groups reveal endemic radiations

Island systems from around the world have provided fascinating opportunities for studies pertaining to various evolutionary processes. One recurring feature of isolated islands is the presence of endemic radiations. In this regard, the Indian subcontinent is an interesting entity given it has been an island during much of its history following separation from Madagascar and currently is isolated from much of Eurasia by the Himalayas in the north and the Indian Ocean in the south. Not surprisingly, recent molecular studies on a number of endemic taxa from India have reported endemic radiations. These studies suggest that the uniqueness of Indian biota is not just due to its diverse origin, but also due to evolution in isolation. The isolation of India has generated some peculiarities typically seen on oceanic islands. However, these patterns might be confined to, groups with low dispersal ability.