Phytoalexin and the resistance and susceptibility of red clover toSclerotinia and Botrytis Spp.

Imperial Users onl

“We need to talk about what race feels like!” Using memory work to analyse the production of race and ethnicity in research encounters

This article is about the production of race and ethnicity in research encounters. It is based on a type of retrospective, comparative memory work, through which we analyse, compare and contrast our respective experiences of moments when race and ethnicity have been produced during our interactions with research participants. We suggest that adding memory work to the analysis of research experiences is one way of exposing the production of race and ethnicity in research interactions, and that a comparative approach to memory work can help clarify how positionalities may not always be good predictors of processes of racialisation in research situations. We also suggest that by looking for instances in which we have felt (or been made to feel) our own ‘difference’ or ‘sameness’, power or a sense disorientation, we may contribute to destabilising the categories and categorisations, which might otherwise go unquestioned in research encounters. Our analysis makes clear how we cannot assume any fixation of where, in whom, or in which topics race or ethnicity is located. We suggest that memory work is a useful tool for learning about the production of race and ethnicity, and comparative or contrastive memory work in collaboration with other researchers differently positioned from oneself is a useful approach when engaging in ‘researching differences’

Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO’s second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h95%0=3.47×10−25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering

Optically targeted search for gravitational waves emitted by core-collapse supernovae during the first and second observing runs of advanced LIGO and advanced Virgo

We present the results from a search for gravitational-wave transients associated with core-collapse supernovae observed within a source distance of approximately 20 Mpc during the first and second observing runs of Advanced LIGO and Advanced Virgo. No significant gravitational-wave candidate was detected. We report the detection efficiencies as a function of the distance for waveforms derived from multidimensional numerical simulations and phenomenological extreme emission models. The sources with neutrino-driven explosions are detectable at the distances approaching 5 kpc, and for magnetorotationally driven explosions the distances are up to 54 kpc. However, waveforms for extreme emission models are detectable up to 28 Mpc. For the first time, the gravitational-wave data enabled us to exclude part of the parameter spaces of two extreme emission models with confidence up to 83%, limited by coincident data coverage. Besides, using ad hoc harmonic signals windowed with Gaussian envelopes, we constrained the gravitational-wave energy emitted during core collapse at the levels of 4.27×10-4 M·c2 and 1.28×10-1 M·c2 for emissions at 235 and 1304 Hz, respectively. These constraints are 2 orders of magnitude more stringent than previously derived in the corresponding analysis using initial LIGO, initial Virgo, and GEO 600 data

Methyl 5,7-dihydr­oxy-2,2,9-trimethyl-6,11-dioxo-6,11-dihydro-2H-anthra[2,3-b]pyran-8-carboxyl­ate

The title compound, C22H18O7, also known as laurentiquinone B, is a new anthraquinone which was isolated from Vismia laurentii, a Cameroonian medicinal plant. The asymmetric unit contains two independent mol­ecules. Each of them contains four fused rings, three of which are coplanar and typical of anthracene, while the heterocyclic rings adopt envelope conformations. Intra­molecular O—H⋯O hydrogen bonds result in the formation of two planar rings, which are also almost coplanar with the adjacent rings. In the crystal structure, inter­molecular O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules and a π–π contact is also present [centroid-centroid distance = 3.967 (3) Å]

An exploration of HBCU first-generation and low-income student experience through the eyes of young alumni

First-generation and low-income (FGLI) college student enrollment numbers are steadily increasing among American colleges and universities. The nation's Historically Black Colleges and Universities (HBCUs) continue to enroll and educate the largest number of African American first-generation and low-income students. As greater access to a college education becomes available, first-generation and low-income students from minoritized backgrounds are taking the opportunity to shift the trajectory of their lives and become the first persons in their families to attend and graduate from college. However, the experiences of these students as they matriculate through college are highly variable as compared to non-first-generation and low-income students. African American FGLI HBCU students require additional targeted student support services and depend heavily on their enrolling institution for basic needs. When basic needs are unmet, this increases the students' chances of facing challenges and barriers that impede their success, achievement, and college completion. Life After College is a qualitative study that examines how ten former first-generation and low-income students from six North Carolina HBCUs navigated college, their college experience as FGLI students, and which challenges they faced in college while striving to reach success. Yosso’s (2005) Community Cultural Wealth framework was used to understand how participants navigated their undergraduate academic progress from a strengths-based perspective. Findings from this study suggest that some African American FGLI HBCU students are extremely dependent on their HBCUs to provide basic needs as they attend college due to their families' inability to do so. In addition, they rely more heavily, than previously thought, on campus and student support services to help them matriculate through college. Findings also reveal that FGLI students can be low-income or very-low-income with very-low-income students being “extremely impoverished”. It is recommended that colleges and universities acknowledge these two very different levels of financial constraints and hardship and consider how to provide extra supports for very-low-income students

Search for subsolar-mass binaries in the first half of advanced LIGO's and advanced virgo's third observing run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M⊙ and 1.0  M⊙ in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr−1. This implies an upper limit on the merger rate of subsolar binaries in the range [220−24200]  Gpc−3 yr−1, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M

Search for intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network

Gravitational-wave astronomy has been firmly established with the detection of gravitational waves from the merger of ten stellar-mass binary black holes and a neutron star binary. This paper reports on the all-sky search for gravitational waves from intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network. The search uses three independent algorithms: two based on matched filtering of the data with waveform templates of gravitational-wave signals from compact binaries, and a third, model-independent algorithm that employs no signal model for the incoming signal. No intermediate mass black hole binary event is detected in this search. Consequently, we place upper limits on the merger rate density for a family of intermediate mass black hole binaries. In particular, we choose sources with total masses M=m1+m2∈[120,800]  M⊙ and mass ratios q=m2/m1∈[0.1,1.0]. For the first time, this calculation is done using numerical relativity waveforms (which include higher modes) as models of the real emitted signal. We place a most stringent upper limit of 0.20  Gpc−3 yr−1 (in comoving units at the 90% confidence level) for equal-mass binaries with individual masses m1,2=100  M⊙ and dimensionless spins χ1,2=0.8 aligned with the orbital angular momentum of the binary. This improves by a factor of ∼5 that reported after Advanced LIGO’s first observing run