Platycorypha nigrivirga Burckhardt (Hemiptera: Sternorrhyncha: Psylloidea), tipu psyllid, new to North America

The tipu psyllid, Platycorypha nigrivirga Burckhardt (Hemiptera: Sternorrhyncha: Psylloidea), is reported for the first time in North America (USA: California). Diagnostic characters for identification of adults and nymphs, host and damage data, and known distribution are given

NMR investigation of the Knight shift anomaly in CeIrIn5 at high magnetic fields

We report nuclear magnetic resonance Knight shift data in the heavy fermion material CeIrIn5 at fields up to 30 T. The Knight shift of the In displays a strong anomaly, and we analyze the results using two different interpretations. We find that the Kondo lattice coherence temperature and the effective mass of the heavy electrons remains largely unaffected by the magnetic field, despite the fact that the Zeeman energy is on the order of the coherence temperature.Comment: 5 pages, 5 figures; to appear in Phys. Rev.

NMR evidence for inhomogeneous glassy behavior driven by nematic fluctuations in iron arsenide superconductors

We present $^{75}$As nuclear magnetic resonance spin-lattice and spin-spin relaxation rate data in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ and Ba(Fe$_{1-x}$Cu$_x$)$_2$As$_2$ as a function of temperature, doping and magnetic field. The relaxation curves exhibit a broad distribution of relaxation rates, consistent with inhomogeneous glassy behavior up to 100 K. The doping and temperature response of the width of the dynamical heterogeneity is similar to that of the nematic susceptibility measured by elastoresistance measurements. We argue that quenched random fields which couple to the nematic order give rise to a nematic glass that is reflected in the spin dynamics.Comment: Accepted to Physical Review

Ezh2-dCas9 and KRAB-dCas9 enable engineering of epigenetic memory in a context-dependent manner.

BackgroundRewriting of the epigenome has risen as a promising alternative to gene editing for precision medicine. In nature, epigenetic silencing can result in complete attenuation of target gene expression over multiple mitotic divisions. However, persistent repression has been difficult to achieve in a predictable manner using targeted systems.ResultsHere, we report that persistent epigenetic memory required both a DNA methyltransferase (DNMT3A-dCas9) and a histone methyltransferase (Ezh2-dCas9 or KRAB-dCas9). We demonstrate that the histone methyltransferase requirement can be locus specific. Co-targeting Ezh2-dCas9, but not KRAB-dCas9, with DNMT3A-dCas9 and DNMT3L induced long-term HER2 repression over at least 50 days (approximately 57 cell divisions) and triggered an epigenetic switch to a heterochromatic environment. An increase in H3K27 trimethylation and DNA methylation was stably maintained and accompanied by a sustained loss of H3K27 acetylation. Interestingly, substitution of Ezh2-dCas9 with KRAB-dCas9 enabled long-term repression at some target genes (e.g., SNURF) but not at HER2, at which H3K9me3 and DNA methylation were transiently acquired and subsequently lost. Off-target DNA hypermethylation occurred at many individual CpG sites but rarely at multiple CpGs in a single promoter, consistent with no detectable effect on transcription at the off-target loci tested. Conversely, robust hypermethylation was observed at HER2. We further demonstrated that Ezh2-dCas9 required full-length DNMT3L for maximal activity and that co-targeting DNMT3L was sufficient for persistent repression by Ezh2-dCas9 or KRAB-dCas9.ConclusionsThese data demonstrate that targeting different combinations of histone and DNA methyltransferases is required to achieve maximal repression at different loci. Fine-tuning of targeting tools is a necessity to engineer epigenetic memory at any given locus in any given cell type

Nuclear magnetic resonance studies of pseudospin fluctuations in URu2_2Si2_2

We report $^{29}$Si NMR measurements in single crystals and aligned powders of URu$_2$Si$_2$ in the hidden order and paramagnetic phases. The spin-lattice-relaxation data reveal evidence of pseudospin fluctuations of U moments in the paramagnetic phase. We find evidence for partial suppression of the density of states below 30 K, and analyze the data in terms of a two component spin-fermion model. We propose that this behavior is a realization of a pseudogap between the hidden order transition $T_{HO}$ and 30 K. This behavior is then compared to other materials that demonstrate precursor fluctuations in a pseudogap regime above a ground state with long-range order.Comment: 5 pages, 3 figure

Holism and non-separability applied to quantum mechanics

Einstein was never satisfied with quantum mechanics. He argued that quantum mechanics was incomplete for two main reasons; it violated the locality principle and the separability principle. The violation of separability is an unavoidable consequence of quantum interactions. Non-separability can be seen in quantum entanglement. Non-locality, however, is more controversial. Einstein and his associates published the EPR paper in order to argue for the incompleteness of quantum mechanics. Years later, John Bell formulated what became known as the Bell Inequalities in response to the EPR paper. The Bell Inequalities are seen as a major obstacle for quantum locality. I will argue that non-locality is not a necessary implication of the Bell Inequalities. The Bell Inequalities were developed using Bell’s locality requirement as a major premise. Bell’s locality requirement can be described in terms of two conditions, parameter independence and outcome independence. A violation of either condition will lead to a violation of the Bell inequalities. Parameter independence is not violated by the results of experimental quantum physics. So, it can be argued that violations of the Bell inequalities are caused by the violation of outcome independence. Such a violation of outcome independence does not imply non-locality if we accept some form of holism or non-separability. Thus, by including some form of holism or non-separability into our picture of the quantum realm we can develop a theory that does not conflict with locality. This paper will discuss different types of holism and non-separability and how they can be used to help understand quantum phenomena

Long range order and two-fluid behavior in heavy electron materials

The heavy electron Kondo liquid is an emergent state of condensed matter that displays universal behavior independent of material details. Properties of the heavy electron liquid are best probed by NMR Knight shift measurements, which provide a direct measure of the behavior of the heavy electron liquid that emerges below the Kondo lattice coherence temperature as the lattice of local moments hybridizes with the background conduction electrons. Because the transfer of spectral weight between the localized and itinerant electronic degrees of freedom is gradual, the Kondo liquid typically coexists with the local moment component until the material orders at low temperatures. The two-fluid formula captures this behavior in a broad range of materials in the paramagnetic state. In order to investigate two-fluid behavior and the onset and physical origin of different long range ordered ground states in heavy electron materials, we have extended Knight shift measurements to URu$_2$Si$_2$, CeIrIn$_5$ and CeRhIn$_5$. In CeRhIn$_5$ we find that the antiferromagnetic order is preceded by a relocalization of the Kondo liquid, providing independent evidence for a local moment origin of antiferromagnetism. In URu$_2$Si$_2$ the hidden order is shown to emerge directly from the Kondo liquid and so is not associated with local moment physics. Our results imply that the nature of the ground state is strongly coupled with the hybridization in the Kondo lattice in agreement with phase diagram proposed by Yang and Pines.Comment: 9 pages, 13 figure

The environmental impact of climate change adaptation on land use and water quality

Encouraging adaptation is an essential aspect of the policy response to climate change1. Adaptation seeks to reduce the harmful consequences and harness any beneficial opportunities arising from the changing climate. However, given that human activities are the main cause of environmental transformations worldwide2, it follows that adaptation itself also has the potential to generate further pressures, creating new threats for both local and global ecosystems. From this perspective, policies designed to encourage adaptation may conflict with regulation aimed at preserving or enhancing environmental quality. This aspect of adaptation has received relatively little consideration in either policy design or academic debate. To highlight this issue, we analyse the trade-offs between two fundamental ecosystem services that will be impacted by climate change: provisioning services derived from agriculture and regulating services in the form of freshwater quality. Results indicate that climate adaptation in the farming sector will generate fundamental changes in river water quality. In some areas, policies that encourage adaptation are expected to be in conflict with existing regulations aimed at improving freshwater ecosystems. These findings illustrate the importance of anticipating the wider impacts of human adaptation to climate change when designing environmental policies

Investigating the mechanisms and functional consequences of DNA damage response engagement by the lentiviral accessory gene Vpr

Diverse viruses modulate the host DNA damage response (DDR) to enhance viral replication or evade innate immune surveillance. Among primate lentiviruses, the conserved and essential accessory gene Vpr engages the DDR at multiple, potentially unique steps: Vpr induces DNA damage, activates and represses the DDR, and causes cell cycle arrest at the G2/M checkpoint. Of the three major DDR signaling kinases, DNA-dependent protein kinase (DNA-PK), ataxia telangiectasia mutated (ATM), and ataxia telangiectasia and Rad3 (ATR), Vpr activates ATM and ATR. The precise nature of this activation remains unclear, however, as do the downstream pathways triggered as a consequence. In this dissertation, I investigate Vpr-mediated ATM and ATR signaling and explore how each might remodel the cell in favor of lentiviral replication. In Chapter 2, I determine that Vpr activates canonical ATM signaling and triggers ATM-NEMO dependent NF-KB/ RelA transcription to remodel the host transcriptome. In Chapter 3, I determine that Vpr-induced ATR activation causes a novel phenotype, nucleolar stress, and characterize the Vpr host target CCDC137 as an important nucleolar stress sensor. Overall, this work encompasses many foundational discoveries that will have important implications for diverse fields, including HIV, nucleolar stress, genome integrity and cancer biology