The merger of two-dimensional radially stratified high-Froude-number vortices

We investigate the influence of density inhomogeneities on the merger of two corotating two-dimensional vortices at infinite Froude number. In this situation, buoyancy effects are negligible, yet density variations still affect the flow by pure inertial effects through the baroclinic torque. We first re-address the effects of a finite Reynolds number on the interaction between two identical Gaussian vortices. Then, by means of direct numerical simulations, we show that vortices transporting light fluid in a heavier counterpart merge from further distances than vortices in a uniform density medium. On the other hand, heavy vortices only merge from small separation distances. We measure the critical distance a/b0 of the vortex radii to their initial separation distance. It departs from the homogeneous threshold of 0.22 in response to increasing density contrasts between the vortices and their surroundings. An analysis of the contribution of the baroclinic vorticity to the dynamics of the flow is detailed and explains the observed behaviour. This analysis is completed by a simple model based on point vortices that mimics the flow. It is concluded that vortices carrying light fluid are more likely to generate large-scale structures than heavy ones in an inhomogeneous fluid

Family Business Research: The Evolution of an Academic Field

The establishment of a field of study or a discipline with academic or professional standing requires, among other things, a body of knowledge that expands understanding of that domain. This paper looks at the literature on establishing a unique field of study, reviews the foundational research in family business (1980s) and four recent years (1997-2001) of published family business research found in several outlets. We find that family business research is becoming increasingly sophisticated and rigorous. This bodes well for the development of an independent field for family business. Recommendations are offered to further the professionalization of family business as an academic and professional domain

Deregulation or re-regulation : grower constructions of risks that arise from regulatory change in the New Zealand pipfruit industry : a thesis submitted in partial fulfilment of the requirements for the degree of Masters of Development Studies, School of Global Studies at Massey University

This thesis seeks to combine two political economy of food perspectives stemming from food regimes analysis and concepts of food networks for the purpose of identifying and examining grower constructions of risks arising from regulatory change in the New Zealand pipfruit industry. While the food regimes framework has received some criticism from the post-structuralist camp, it is difficult to conceive how a clear understanding of agri-food networks in New Zealand, particularly post-1984, could be proposed without focusing on the momentous political and economic events associated with the structural adjustment experiment which fundamentally changed the productive, investment, economic and socio-political landscapes. Food regimes analysis, with its focus on investment axes and comparative trends in global food restructuring, represents a powerful theoretical tool in situating historical and current industry challenges and structural conditions. The research uses focus groups as the primary participatory research vehicle and through this has identified grower defined, risk matrices. These matrices have been built in four separate pipfruit growing regions. Each prioritises risk events in terms of likelihood of occurrence and seriousness of consequence, in the orchard business enterprise context. Regionally specific risk construction and definition can assist in the prediction, and analysis, of the effects of deregulation (re-regulation), and influence future development trajectories for the New Zealand pipfruit industry and the regional communities where the industry is a major economic driver. Key Words: food regimes; food networks; qualitative method; focus group; risk; construction

Characterization of a core fragment of the rhesus monkey TRIM5α protein

<p>Abstract</p> <p>Background</p> <p>Like all tripartite motif (TRIM) proteins, the retroviral restriction factor TRIM5α consists of RING, B-box 2 and coiled-coil domains, with a C-terminal B30.2(SPRY) domain. Although structures have been determined for some individual TRIM domains, the structure of an intact TRIM protein is unknown.</p> <p>Results</p> <p>Here, we express and characterize a protease-resistant 29-kD core fragment containing the B-box 2, coiled coil and adjacent linker (L2) region of TRIM5α. This BCCL2 protein formed dimers and higher-order oligomers in solution. Approximately 40% of the BCCL2 secondary structure consisted of alpha helices. Partial loss of alpha-helical content and dissociation of dimers occurred at 42°C, with the residual alpha helices remaining stable up to 80°C.</p> <p>Conclusions</p> <p>These results indicate that the B-box 2, coiled-coil and linker 2 regions of TRIM5α form a core dimerization motif that exhibits a high level of alpha-helical content.</p

Paragneiss Zircon Geochronology and Trace Element Geochemistry, North Qaidam HP/UHP Terrane, Western China

In the southeastern part of the North Qaidam terrane, near Dulan, paragneiss hosts minor peridotite and UHP eclogite. Zircon geochronology and trace element geochemistry of three paragneiss samples (located within a ∼3 km transect) indicates that eclogite-facies metamorphism resulted in variable degrees of zircon growth and recrystallization in the three samples. Inherited zircon core age groups at 1.8 and 2.5 Ga suggest that the protoliths of these rocks may have received sediments from the Yangtze or North China cratons. Mineral inclusions, depletion in HREE, and absence of negative Eu anomalies indicate that zircon U-Pb ages of 431 ± 5 Ma and 426 ± 4 Ma reflect eclogite-facies zircon growth in two of the samples. Ti-in-zircon thermometry results are tightly grouped at ∼660 and ∼600 °C, respectively. Inclusions of metamorphic minerals, scarcity of inherited cores, and lack of isotopic or trace element inheritance demonstrate that significant new metamorphic zircon growth must have occurred. In contrast, zircon in the third sample is dominated by inherited grains, and rims show isotopic and trace element inheritance, suggesting solid-state recrystallization of detrital zircon with only minor new growth

Frame Indifferent Formulation of Maxwell's Elastic Fluid and the Rational Continuum Mechanics of the Electromagnetic Field

We show that the linearized equations of the incompressible elastic medium admit a `Maxwell form' in which the shear component of the stress vector plays the role of the electric field, and the vorticity plays the role of the magnetic field. Conversely, the set of dynamic Maxwell equations are strict mathematical corollaries from the governing equations of the incompressible elastic medium. This suggests that the nature of `electromagnetic field' may actually be related to an elastic continuous medium. The analogy is complete if the medium is assumed to behave as fluid in shear motions, while it may still behave as elastic solid under compressional motions. Then the governing equations of the elastic fluid are re-derived in the Eulerian frame by replacing the partial time derivatives by the properly invariant (frame indifferent) time rates. The `Maxwell from' of the frame indifferent formulation gives the frame indifferent system that is to replace the Maxwell system. This new system comprises terms already present in the classical Maxwell equations, alongside terms that are the progenitors of the Biot--Savart, Oersted--Ampere's, and Lorentz--force laws. Thus a frame indifferent (truly covariant) formulation of electromagnetism is achieved from a single postulate that the electromagnetic field is a kind of elastic (partly liquid partly solid) continuum.Comment: accepte

Stretching of polymers in a turbulent environment

The interaction of polymers with small-scale velocity gradients can trigger a coil-stretch transition in the polymers. We analyze this transition within a direct numerical simulation of shear turbulence with an Oldroyd-B model for the polymer. In the coiled state the lengths of polymers are distributed algebraically with an exponent alpha=2 gamma-1/De, where gamma is a characteristic stretching rate of the flow and De the Deborah number. In the stretched state we demonstrate that the length distribution of the polymers is limited by the feedback to the flow

The major human and mouse granzymes are structurally and functionally divergent

Approximately 2% of mammalian genes encode proteases. Comparative genomics reveals that those involved in immunity and reproduction show the most interspecies diversity and evidence of positive selection during evolution. This is particularly true of granzymes, the cytotoxic proteases of natural killer cells and CD8+ T cells. There are 5 granzyme genes in humans and 10 in mice, and it is suggested that granzymes evolve to meet species-specific immune challenge through gene duplication and more subtle alterations to substrate specificity. We show that mouse and human granzyme B have distinct structural and functional characteristics. Specifically, mouse granzyme B is 30 times less cytotoxic than human granzyme B and does not require Bid for killing but regains cytotoxicity on engineering of its active site cleft. We also show that mouse granzyme A is considerably more cytotoxic than human granzyme A. These results demonstrate that even “orthologous” granzymes have species-specific functions, having evolved in distinct environments that pose different challenges

Geochronology and Tectonic Significance of Middle Proterozoic Granitic Orthogneiss, North Qaidam HP/UHP Terrane, Western China

Amphibolite-facies para- and orthogneisses near Dulan, in the southeast part of the North Qaidam terrane, enclose minor ultra-high pressure (UHP) eclogite and peridotite. Field relations and coesite inclusions in zircons from paragneiss suggest that felsic, mafic, and ultramafic rocks all experienced UHP metamorphism and a common amphibolite-facies retrogression. Ion microprobe U–Pb and REE analyses of zircons from two granitic orthogneisses indicate magmatic crystallization at 927 ± Ma and 921 ± 7 Ma. Zircon rims in one of these samples yield younger ages (397–618 Ma) compatible with partial zircon recrystallization during in-situ Ordovician-Silurian eclogite-facies metamorphism previously determined from eclogite and paragneiss in this area. The similarity between a 2496 ± 18 Ma xenocrystic core and 2.4–2.5 Ga zircon cores in the surrounding paragneiss suggests that the granites intruded the sediments or that the granite is a melt of the older basement which supplied detritus to the sediments. The magmatic ages of the granitic orthogneisses are similar to 920–930 Ma ages of (meta)granitoids described further northwest in the North Qaidam terrane and its correlative west of the Altyn Tagh fault, suggesting that these areas formed a coherent block prior to widespread Mid Proterozoic granitic magmatism. Included here is the post-print copy of this article. The final publication is available at Springer via http://dx.doi.org/10.1007/s00710-006-0149-1

2017 Final Evaluation Report for Better Together

Program DescriptionHeartland Family Service (HFS) partnered with Nebraska Families Collaborative (NFC) and the Nebraska Department of Health and Human Services (NDHHS) to begin Better Together, a comprehensive support service program for families affected by substance abuse in Omaha, Nebraska. Better Together seeks to prevent infant abandonment by increasing wellbeing, improving permanency, and enhancing the safety of infants and young children who have been exposed to dangerous drugs. Utilizing a community-based treatment setting, Better Together provides intensive outpatient and outpatient substance abuse treatment to families impacted by substance abuse. NDHHS and NFC identify families as being at risk for out-of-home placement of their children and recommend the appropriate services. The target population is families in which the mother is pregnant and using drugs and/or alcohol, families where infants screen positive for illegal substances, or families with young children who are at risk for placement due to parental substance abuse. HFS treats each family as a unit, providing comprehensive treatment and support services for the parents, infants, young children, older children, and any self-identified family members. Better Together services include the following: Intensive outpatient and outpatient substance abuse treatment. Mental health treatment. Case management. Parenting education. Peer support. Family therapy. Housing assistance. Infant and child developmental screening and intervention. Physical health care coordination and support. Transportation assistance. Families live in a community-based treatment setting, in individually-leased apartments, for up to two years. As they move through the program, their treatment becomes progressively less intensive. Better Together outcomes include improved child well-being, sustained parental recovery from substance abuse, and reunification of families