Ten polymorphic microsatellite primers in the tropical tree caimito, Chrysophyllum cainito (Sapotaceae).

UnlabelledPremise of the studyWe developed microsatellite primers for the tropical tree Chrysophyllum cainito (Sapotaceae) to determine the native range of the species, investigate the origin of cultivated populations, and examine the partitioning of genetic diversity in wild and cultivated populations. •Methods and resultsWe developed 10 polymorphic primers from C. cainito genomic DNA libraries enriched for di-, tri-, and tetranucleotide repeat motifs. The loci amplified were polymorphic in samples collected from Jamaica and Panama. The number of alleles per locus ranged from two to 10 and three to 12, while observed heterozygosities ranged from 0.074 to 0.704 and 0.407 to 0.852 in Jamaica and Panama, respectively. •ConclusionsThe microsatellite primers will be useful in future population genetic studies as well as those aimed at understanding the geographic origin(s) of wild and cultivated populations

Ethical Issues Arising When a Lawyer Leaves a Firm: Restrictions on Practice

Restriction on covenants not to compete have been a long-time feature of legal practice. Rules prohibiting law firms from restricting lawyers\u27 ability to practice or imposing penalties on lawyers that leave a firm attempt to balance the law firm\u27s interest in survival in a competitive market with the countervailing interests of attorney mobility, and protecting clients\u27 choice of counsel. Restrictions on covenants not to compete should be vigorously enforced, and the exception that allows for the forfeiture of retirement benefits by attorneys that choose to leave a firm should be narrowly applied to only those funds to which the departing attorney is not already entitled

Ethical Issues Arising When a Lawyer Leaves a Firm: Restrictions on Practice

Restriction on covenants not to compete have been a long-time feature of legal practice. Rules prohibiting law firms from restricting lawyers\u27 ability to practice or imposing penalties on lawyers that leave a firm attempt to balance the law firm\u27s interest in survival in a competitive market with the countervailing interests of attorney mobility, and protecting clients\u27 choice of counsel. Restrictions on covenants not to compete should be vigorously enforced, and the exception that allows for the forfeiture of retirement benefits by attorneys that choose to leave a firm should be narrowly applied to only those funds to which the departing attorney is not already entitled

Terrace grading of SiGe for high-quality virtual substrates

Silicon germanium (SiGe) virtual substrates of final germanium composition x = 0.50 have been fabricated using solid-source molecular beam epitaxy with a thickness of 2 µm. A layer structure that helps limit the size of dislocation pileups associated with the modified Frank–Read dislocation multiplication mechanism has been studied. It is shown that this structure can produce lower threading dislocation densities than conventional linearly graded virtual substrates. Cross-sectional transmission electron microscopy shows the superior quality of the dislocation network in the graded regions with a lower rms roughness shown by atomic force microscopy. X-ray diffractometry shows these layers to be highly relaxed. This method of Ge grading suggests that high-quality virtual substrates can be grown considerably thinner than with conventional grading methods

Misfit strain relaxation and dislocation formation in supercritical strained silicon on virtual substrates

Relaxation of strained silicon on 20% linear graded virtual substrates was quantified using high resolution x-ray diffraction and a defect etching technique. The thickness of strained silicon was varied between 10 and 180 nm. Relaxation was observed in layers below the critical thickness but increased to only 2% relaxation in the thickest layers even with annealings up to 950 °C. Cross-sectional transmission electron microscopy revealed stacking faults present in layers thicker than 25 nm, and nucleated 90° Shockley partial dislocations forming microtwins in the thickest layer. These features are implicated in the impediment of the relaxation process

Vortexability: A Unifying Criterion for Ideal Fractional Chern Insulators

Fractional Chern insulators realize the remarkable physics of the fractional quantum Hall effect (FQHE) in crystalline systems with Chern bands. The lowest Landau level (LLL) is known to host the FQHE, but not all Chern bands are suitable for realizing fractional Chern insulators (FCI). Previous approaches to stabilizing FCIs focused on mimicking the LLL through momentum space criteria. Here instead we take a real-space perspective by introducing the notion of vortexability. Vortexable Chern bands admit a fixed operator that introduces vortices into any band wavefunction while keeping the state entirely within the same band. Vortexable bands admit trial wavefunctions for FCI states, akin to Laughlin states. In the absence of dispersion and for sufficiently short ranged interactions, these FCI states are the ground state -- independent of the distribution of Berry curvature. Vortexable bands are much more general than the LLL, and we showcase a recipe for constructing them. We exhibit diverse examples in graphene-based systems with or without magnetic field, and with any Chern number. A special class of vortexable bands is shown to be equivalent to the momentum space ``trace condition" or ``ideal band condition". In addition, we also identify a more general form of vortexability that goes beyond this criterion. We introduce a modified measure that quantifies deviations from general vortexability which can be applied to generic Chern bands to identify promising FCI platforms.Comment: 9 pages, 3 figures main text. 26 pages, 4 figures including supplement. Corrections to example E2 of V

Acceleration of the universe, vacuum metamorphosis, and the large-time asymptotic form of the heat kernel

We investigate the possibility that the late acceleration observed in the rate of expansion of the universe is due to vacuum quantum effects arising in curved spacetime. The theoretical basis of the vacuum cold dark matter (VCDM), or vacuum metamorphosis, cosmological model of Parker and Raval is revisited and improved. We show, by means of a manifestly nonperturbative approach, how the infrared behavior of the propagator (related to the large-time asymptotic form of the heat kernel) of a free scalar field in curved spacetime causes the vacuum expectation value of its energy-momentum tensor to exhibit a resonance effect when the scalar curvature R of the spacetime reaches a particular value related to the mass of the field. we show that the back reaction caused by this resonance drives the universe through a transition to an accelerating expansion phase, very much in the same way as originally proposed by Parker and Raval. Our analysis includes higher derivatives that were neglected in the earlier analysis, and takes into account the possible runaway solutions that can follow from these higher-derivative terms. We find that the runaway solutions do not occur if the universe was described by the usual classical FRW solution prior to the growth of vacuum energy-density and negative pressure (i.e., vacuum metamorphosis) that causes the transition to an accelerating expansion of the universe in this theory.Comment: 33 pages, 3 figures. Submitted to Physical Review D15 (Dec 23, 2003). v2: 1 reference added. No other change

Protein Kinase Cε Is Required for Macrophage Activation and Defense Against Bacterial Infection

To assess directly the role of protein kinase C (PKC)ε in the immune system, we generated mice that carried a homozygous disruption of the PKCε locus. PKCε−/− animals appeared normal and were generally healthy, although female mice frequently developed a bacterial infection of the uterus. Macrophages from PKCε−/− animals demonstrated a severely attenuated response to lipopolysaccharide (LPS) and interferon (IFN)γ, characterized by a dramatic reduction in the generation of NO, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β. Further analysis revealed that LPS-stimulated macrophages from PKCε−/− mice were deficient in the induction of nitric oxide synthase (NOS)-2, demonstrating a decrease in the activation of IκB kinase, a reduction in IκB degradation, and a decrease in nuclear factor (NF)κB nuclear translocation. After intravenous administration of Gram-negative or Gram-positive bacteria, PKCε−/− mice demonstrated a significantly decreased period of survival. This study provides direct evidence that PKCε is critically involved at an early stage of LPS-mediated signaling in activated macrophages. Furthermore, we demonstrate that in the absence of PKCε, host defense against bacterial infection is severely compromised, resulting in an increased incidence of mortality