Consistency and sensitivity of stream periphyton community structural and functional responses to nutrient enrichment

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117222/1/eap2013231159.pd

The Phase Structure of Supersymmetric Sp(2N_c) Gauge Theories with an Adjoint

We study the phase structure of N = 1 supersymmetric Sp(2N_c) gauge theories with 2N_f fundamentals, an adjoint, and vanishing superpotential. Using a-maximization, we derive analytic expressions for the values of N_f below which the first several gauge-invariant operators in the chiral ring violate the unitarity bound and become free fields. In doing so we are able to explicitly check previous conjectures about the behavior of this theory made by Luty, Schmaltz, and Terning. We then compare this to an analysis of the first two 'deconfined' dual descriptions based on the gauge groups Sp(2N_f+2) x SO(2N_c+5) and Sp(2N_f+2) x SO(4N_f+4) x Sp(2N_c+2), finding precise agreement. In particular, we find no evidence for non-obvious accidental symmetries or the appearance of a mixed phase in which one of the dual gauge groups becomes free.Comment: 18 pages, 2 figures; v2: added references to match JHEP versio

Accessing monomers, surfactants, and the queen bee substance by acrylate cross-metathesis of long-chain alkenones

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Journal of the American Oil Chemists' Society 94 (2017): 831-840, doi: 10.1007/s11746-017-2997-8.Polyunsaturated long-chain alkenones are a unique class of lipids biosynthesized in significant quantities (up to 20% of cell carbon) by several algae including the industrially grown marine microalgae Isochrysis. Alkenone structures are characterized by a long linear carbon-chain (35-40 carbons) with one to four trans-double bonds and terminating in a methyl or ethyl ketone. Alkenones were extracted and isolated from commercially obtained Isochrysis biomass and then subjected to cross-metathesis (CM) with methyl acrylate or acrylic acid using the Hoveyda-Grubbs metathesis initiator. Within 1 h at room temperature alkenones were consumed, however complete fragmentation (i.e. conversion to the smallest subunits by double bond cleavage) required up to 16 h. Analysis of the reaction mixture by gas chromatography and comprehensive two-dimensional gas chromatography revealed a predictable product mixture consisting primarily of long-chain (mostly C17) acids (or methyl esters from CM with methyl acrylate) and diacids (or diesters), along with smaller amounts (~5%) of the honey bee “queen substance” (E)-9-oxo-decenoic acid. Together, these compounds comprise a diverse mixture of valuable chemicals that includes surfactants, monomers, and an agriculturally relevant bee pheromone.This work was supported by the National Science Foundation (CHE- 1151492) and through a private donation from friends of WHOI

Parental psychological control dimensions: Connections with Russian preschoolers\u27 physical and relational aggression

Parental psychological control generally consists of overinvolved/protective and critical/rejecting elements, both being linked to children\u27s psychosocial maladjustment. The critical/rejecting element is multidimensional in nature, and few studies have explored this conceptual fullness. It is possible that some dimensions, if they can be statistically differentiated, are uniquely tied to various child behaviors. This may help resolve some of the inconsistency apparent across studies, such as studies of relational aggression. Accordingly, we examined the association between parental psychological control and childhood physical and relational aggression using a dimensional approach. Participants were 204 Russian preschoolers and their parents. The results revealed that dimensions of psychosocial control (i.e., shaming/disappointment, constraining verbal expressions, invalidating feelings, love withdrawal, and guilt induction) could be statistically differentiated, even though most dimensions tended to be significantly correlated. Furthermore, all dimensions, except for invalidating feelings, were significantly associated with childhood aggression, but predominantly in same-gender parent-child dyads. © 2012 Elsevier Inc.

Marital satisfaction and depressive symptoms in China

Although there is substantial evidence that low marital satisfaction is a significant risk factor for depression, little research has examined this relationship in cultures outside of the U.S. and Europe. The validity of the marital discord model of depression in Chinese culture was tested by studying 391 couples living in Beijing and Hangzhou, China. Results of structural equation modeling using an actor-partner interdependence model strategy indicated that husbands\u27 and wives\u27 marital satisfaction was significantly predictive of their own depressive symptoms. In addition, wives\u27 marital satisfaction significantly predicted husbands\u27 depressive symptoms. These results provide evidence that the marital discord model of depression is useful in understanding the role of marital dissatisfaction as a risk factor for depressive symptoms in collectivistic societies, such as China. © 2013 American Psychological Association

Correlates of sociometric status in Russian preschoolers: Aggression, victimization, and sociability

© 2016 Elsevier Ltd. Few studies have assessed behavioral correlates of preschool children\u27s peer sociometric status in cultures outside North America. This study focuses on 221 Russian preschoolers (108 boys, 113 girls). Correlates included physical and relational forms of aggression/victimization and sociable behavior. Confirmatory Factor Analyses (CFA) established that study instruments originally developed with U.S. preschoolers worked well in Russia. Findings in regard to aggression, sociability, and victimization were generally consistent with previous research with American and Italian preschoolers, particularly in regard to controversial status children. Our findings further challenge the notion that controversial children are consistently savvy in their social interactions. They and rejected children were most likely to be physically and relationally victimized by their peers

Flavor of quiver-like realizations of effective supersymmetry

We present a class of supersymmetric models which address the flavor puzzle and have an inverted hierarchy of sfermions. Their construction involves quiver-like models with link fields in generic representations. The magnitude of Standard-Model parameters is obtained naturally and a relatively heavy Higgs boson is allowed without fine tuning. Collider signatures of such models are possibly within the reach of LHC in the near future.Comment: LaTeX, 17 pages, 3 figures. V2: reference adde

Tumor necrosis factor-alpha is produced by dying retinal neurons and is required for Müller glia proliferation during zebrafish retinal regeneration

Intense light exposure causes photoreceptor apoptosis in dark-adapted adult albino zebrafish (Danio rerio). Subsequently, Müller glia increase expression of the Achaete-scute complex-like 1a (Ascl1a) and Signal transducer and activator of transcription 3 (Stat3) transcription factors and re-enter the cell cycle to yield undifferentiated neuronal progenitors that continue to proliferate, migrate to the outer nuclear layer, and differentiate into photoreceptors. A proteomic analysis of light-damaged retinal homogenates, which induced Müller glia proliferation when injected into an undamaged eye, revealed increased expression of tumor necrosis factor α (TNFα) signaling proteins relative to undamaged retinal homogenates. TNFα expression initially increased in apoptotic photoreceptors and later in Müller glia. Morpholino-mediated knockdown of TNFα expression before light damage diminished the expression of both Ascl1a and Stat3 in Müller glia and significantly reduced the number of proliferating Müller glia without affecting photoreceptor cell death. Knockdown of TNFα expression in the Müller glia resulted in fewer proliferating Müller glia, suggesting that Müller glial-derived TNFα recruited additional Müller glia to re-enter the cell cycle. While TNFα is required for increased Ascl1a and Stat3 expression, Ascl1a and Stat3 are both necessary for TNFα expression in Müller glia. Apoptotic inner retinal neurons, resulting from intravitreal injection of ouabain, also exhibited increased TNFα expression that was required for Müller glia proliferation. Thus, TNFα is the first molecule identified that is produced by dying retinal neurons and is necessary to induce Müller glia to proliferate in the zebrafish retinal regeneration response. © 2013 the authors