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"Laura M."
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Deadly actin collapse by disulfidptosis
Programmed cell death (PCD) enables cells to co-ordinate their exit to benefit the surviving organism. A new study describes how cells can programme their death by inducing extensive disulfide bonding of the actin cytoskeleton in response to an imbalance of cystine, a raw material for glutathione production.
Journal Article
A triple protostar system formed via fragmentation of a gravitationally unstable disk
Observations of the triple protostar system L1448 IRS3B support the hypothesis that companion stars can form because of gravitational instability in a protostellar disk.
Gravitational instability in a triple-star system
Multiple stars that orbit each other, a common occurrence across the Universe, result from the early-stage fragmentation of molecular clouds. John Tobin
et al
. report observations of the triple protostar system L1448 IRS3B, which is in an early phase of the star formation process, making it an ideal candidate for the search for evidence of disk fragmentation. They find dust and molecular gas emissions that indicate a disk with a spiral structure surrounding the three protostars. They demonstrate that this disk is susceptible to fragmentation, supporting the hypothesis that companion stars can form as a result of gravitational instability in a protostellar disk.
Binary and multiple star systems are a frequent outcome of the star formation process
1
,
2
and as a result almost half of all stars with masses similar to that of the Sun have at least one companion star
3
. Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large-scale fragmentation of turbulent gas cores and filaments
4
,
5
or smaller-scale fragmentation of a massive protostellar disk due to gravitational instability
6
,
7
. Observational evidence for turbulent fragmentation on scales of more than 1,000 astronomical units has recently emerged
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,
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. Previous evidence for disk fragmentation was limited to inferences based on the separations of more-evolved pre-main sequence and protostellar multiple systems
10
,
11
,
12
,
13
. The triple protostar system L1448 IRS3B is an ideal system with which to search for evidence of disk fragmentation as it is in an early phase of the star formation process, it is likely to be less than 150,000 years old
14
and all of the protostars in the system are separated by less than 200 astronomical units. Here we report observations of dust and molecular gas emission that reveal a disk with a spiral structure surrounding the three protostars. Two protostars near the centre of the disk are separated by 61 astronomical units and a tertiary protostar is coincident with a spiral arm in the outer disk at a separation of 183 astronomical units
13
. The inferred mass of the central pair of protostellar objects is approximately one solar mass, while the disk surrounding the three protostars has a total mass of around 0.30 solar masses. The tertiary protostar itself has a minimum mass of about 0.085 solar masses. We demonstrate that the disk around L1448 IRS3B appears susceptible to disk fragmentation at radii between 150 and 320 astronomical units, overlapping with the location of the tertiary protostar. This is consistent with models for a protostellar disk that has recently undergone gravitational instability, spawning one or two companion stars.
Journal Article
Indigenous cities : urban Indian fiction and the histories of relocation
\"In Indigenous Cities Laura M. Furlan demonstrates that stories of the urban experience are essential to an understanding of modern Indigeneity. She situates Native identity among theories of diaspora, cosmopolitanism, and transnationalism by examining urban narratives--such as those written by Sherman Alexie, Janet Campbell Hale, Louise Erdrich, and Susan Power--along with the work of filmmakers and artists. In these stories, Native peoples navigate new surroundings, find and reformulate community, and maintain and redefine Indian identity in the postrelocation era. These narratives illuminate the changing relationship between urban Indigenous peoples and theirtribal nations and territories and the ways in which new cosmopolitan bonds both reshape and are interpreted by tribal identities. Though the majority of American Indigenous populations do not reside on reservations, these spaces regularly define discussions and literature about Native citizenship and identity. Meanwhile, conversations about the shift to urban settings often focus on elements of dispossession, subjectivity, and assimilation. Furlan takes a critical look at Indigenous fiction from the last three decades to present a new way of looking at urban experiences that explains mobility and relocation as a form of resistance. In these stories Indian bodies are not bound by state-imposed borders or confined to Indian Country as it is traditionally conceived. Furlan demonstrates that cities have always been Indian land and Indigenous peoples have always been cosmopolitan and urban.\"-- Provided by publisher.
Book
Overview of Extracellular Vesicles, Their Origin, Composition, Purpose, and Methods for Exosome Isolation and Analysis
The use of extracellular vesicles, specifically exosomes, as carriers of biomarkers in extracellular spaces has been well demonstrated. Despite their promising potential, the use of exosomes in the clinical setting is restricted due to the lack of standardization in exosome isolation and analysis methods. The purpose of this review is to not only introduce the different types of extracellular vesicles but also to summarize their differences and similarities, and discuss different methods of exosome isolation and analysis currently used. A thorough understanding of the isolation and analysis methods currently being used could lead to some standardization in the field of exosomal research, allowing the use of exosomes in the clinical setting to become a reality.
Journal Article
Teaching struggling students : lessons learned from both sides of the classroom
\"This text tackles the phenomenon of limited learning on campuses by approaching it from the point of view of the author, an educator who writes about the experience of being, simultaneously, a college student and a college professor. The author lays out her experience as a student struggling in an introductory linguistics class, framing her struggles as sites ripe for autoethnographic interrogation. Throughout the book, the author melds her personal narratives with the extant research on college student learning, college readiness, and the interconnectedness of affect, intellect, and socio-cultural contexts\"-- Provided by publisher.
Book
Spiral density waves in a young protoplanetary disk
Gravitational forces are expected to excite spiral density waves in protoplanetary disks, disks of gas and dust orbiting young stars. However, previous observations that showed spiral structure were not able to probe disk midplanes, where most of the mass is concentrated and where planet formation takes place. Using the Atacama Large Millimeter/submillimeter Array, we detected a pair of trailing symmetric spiral arms in the protoplanetary disk surrounding the young star Elias 2-27. The arms extend to the disk outer regions and can be traced down to the midplane. These millimeter-wave observations also reveal an emission gap closer to the star than the spiral arms. We argue that the observed spirals trace shocks of spiral density waves in the midplane of this young disk.
Journal Article
Slow and steady wins the race: The behaviour and welfare of commercial faster growing broiler breeds compared to a commercial slower growing breed
Broilers have been bred for fast growth which has led to welfare problems such as high mortality, lameness and skin lesions. Slower growing breeds are thought to have better welfare but are not as efficient in production. This study investigated welfare, behaviour, production and meat quality of faster growing broilers from three main commercial broiler companies (breeds FA, FB and FC) with a commercially available slower growing breed (Hubbard JA757, S). Four hundred birds of each breed (total 1600 birds) were reared in pens of 50 birds, 8 per breed (total 32 pens). Home pen behaviour was recorded once a week in hourly scan samples to get behavioural time budgets. Welfare Assessments (WA) were done when the average bird weight per breed was 2.2 and 2.5kg. Birds and feed supplied were regularly weighed by pen and Feed Conversion Ratio (FCR) and Average Daily Gain (ADG) were calculated at 2.2kg. Birds were then slaughtered and meat quality measures were taken. S and FC had lower mortality and culls due to lameness (P<0.05 for both). Breeds FA, FB and FC grew faster, ate less feed and had better FCR and ADG (P<0.05 for all). S had scores indicating higher welfare for the majority of WA measures and spent more time active and less time sitting, feeding and drinking than the other breeds (P<0.05 for all). Faster growing breeds had more breast meat and S had more leg meat; although S had better meat quality scores (P<0.05). Overall, S birds have improved welfare in terms of activity and welfare measure scores compared to the other breeds but take longer to reach slaughter weight and are not as efficient in production measures. However if lower mortality and improved meat quality are taken into account, as well as the premium price paid for these birds, slower growing broilers may be a viable commercial option.
Journal Article