157 research outputs found
Interview with Paul Krassner
In his July 1992 interview with Ron Chepesiuk, Paul Krassner described his time as an anti-war activist during the 1960s and his current work. Krassner covered topics of satire, drugs, other activists, the Chicago Conspiracy Trial, the FBI and its involvement, Groucho Marx, and other conspiracies. He also detailed events like the levitating of the Pentagon and America’s Youth March on the Democratic Convention. Krassner, known as being the father of the Underground Press, was then continuing his satirical writing, critiquing the world. This interview was conducted for inclusion into the Louise Pettus Archives and Special Collections Oral History Program.https://digitalcommons.winthrop.edu/oralhistoryprogram/1140/thumbnail.jp
3 MHz Space Observatory
Little is known about the radio astronomical universe at frequencies below 10
MHz because such radiation does not penetrate the ionosphere. A cubesat-based
telescope for the 1--10 MHz band could be rapidly and economically deployed in
low earth orbit. We consider possible transient and steady sources, and
application to study of the ionosphere itself.Comment: 5 pp., 1 fi
Postmortem changes in brain cell structure: a review
Brain cell structure is a key determinant of neural function that is frequently altered in neurobiological disorders. Following the global loss of blood flow to the brain that initiates the postmortem interval (PMI), cells rapidly become depleted of energy and begin to decompose. To ensure that our methods for studying the brain using autopsy tissue are robust and reproducible, there is a critical need to delineate the expected changes in brain cell morphometry during the PMI. We searched multiple databases to identify studies measuring the effects of PMI on the morphometry (i.e. external dimensions) of brain cells. We screened 2119 abstracts, 361 full texts, and included 172 studies. Mechanistically, fluid shifts causing cell volume alterations and vacuolization are an early event in the PMI, while the loss of the ability to visualize cell membranes altogether is a later event. Decomposition rates are highly heterogenous and depend on the methods for visualization, the structural feature of interest, and modifying variables such as the storage temperature or the species. Geometrically, deformations of cell membranes are common early events that initiate within minutes. On the other hand, topological relationships between cellular features appear to remain intact for more extended periods. Taken together, there is an uncertain period of time, usually ranging from several hours to several days, over which cell membrane structure is progressively lost. This review may be helpful for investigators studying human postmortem brain tissue, wherein the PMI is an unavoidable aspect of the research
Infrared photometric study of the massive star forming region S235 using Spitzer-IRAC and JHK observations
We present the {\it Spitzer}-IRAC images of the S235 star forming complex
that includes the East~1 & 2, Central and S235 A & B regions. In addition, we
present the near-infrared images of the S235 A & B regions. The IRAC photometry
reveals on-going star formation, with 86 Class 0/I and 144 Class II YSOs in the
entire S235 complex. Nearly 73% of these YSOs are present in clusters with a
maximum surface density of 120 YSOs/pc (in the vicinity of S235A & B
regions). A few YSOs, possibly in an arc-like formation, are identified towards
the south of S235A region, which may be speculated as an evidence for
magnetically super-critical collapse. One of the sources in the arc-like
formation, namely S235AB-MIR, seems to be a young, massive star that is still
accreting matter. SED modeling of some of the newly identified YSOs confirms
the classification made on the basis of IRAC colours. The IRAC ratio map of
Ch2/Ch4 traces clearly the Br emission associated with the HII region
of S235A within the horse-shoe envelope. Outside the horse-shoe structure, the
ratio map indicates shock-excited H emission. Br emission is also
seen around S235B (from the ratio map). The ratio map of Ch2/Ch4 reveals that
the source "e2s3" in the East~2 region may be associated with shock-excited
H emission outflow or jet. The SED modeling of this new source indicates
that it is a very young massive star that is not yet able to drive an HII
region.Comment: 19 pages; 13 figures; 8 tables. Accepted in MNRAS, Feb 201
A multi-transition molecular line study of inward motions towards massive star-forming cores
A multi-transition 3mm molecular line single-pointing and mapping survey
was carried out towards 29 massive star-forming cores in order to search for
the signature of inward motions. Up to seven different transitions, optically
thick lines HCO(1-0), CS(2-1), HNC(1-0), HCN(1-0), CO(1-0) and
optically thin lines CO(1-0), CO(1-0) were observed towards each
source. The normalized velocity differences (V,
V) between the peak velocities of optically thick lines
and optically thin line CO(1-0) for each source were derived. Prominent
inward motions are probably present in either HCO(1-0) or CS(2-1) or
HNC(1-0) observations in most sources. Our observations show that there is a
significant difference in the incidence of blue shifted line asymmetric line
profiles between CS(2-1) and HCO(1-0). The HCO(1-0) shows the highest
occurrence of obvious asymmetric feature, perhaps owing to different optical
depth between CS(2-1) and HCO(1-0). HCO(1-0) appears to be the best
inward motion tracer. The mapping observations of multiple line transitions
enable us to identify six strong infall candidates G123.07-6.31, W75(OH),
S235N, CEP-A, W3(OH), NGC7538. The infall signature is extended up to a linear
scale pc.Comment: 11 pages, 10 figures, 3 tables, accepted for publication in MNRA
New signposts of massive star formation in the S235A-B region
We report on new aspects of the star-forming region S235AB revealed through
high-resolution observations at radio and mid-infrared wavelengths. Using the
Very Large Array, we carried out sensitive observations of S235AB in the cm
continuum (6, 3.6, 1.3, and 0.7) and in the 22 GHz water maser line. These were
complemented with Spitzer Space Telescope Infrared Array Camera archive data to
clarify the correspondence between radio and IR sources. We made also use of
newly presented data from the Medicina water maser patrol, started in 1987, to
study the variability of the water masers found in the region. S235A is a
classical HII region whose structure is now well resolved. To the south, no
radio continuum emission is detected either from the compact molecular core or
from the jet-like structure observed at 3.3 mm, suggesting emission from dust
in both cases. We find two new compact radio continuum sources (VLA-1 and
VLA-2) and three separate maser spots. VLA-1 coincides with one of the maser
spots and with a previously identified IR source (M1). VLA-2 lies towards S235B
and represents the first radio detection from this peculiar nebula that may
represent an ionized wind from a more evolved star. The two other maser spots
coincide with an elongated structure previously observed within the molecular
core in the C34S line. This structure is perpendicular to a bipolar molecular
outflow observed in HCO+(1-0) and may trace the associated equatorial disk. The
Spitzer images reveal a red object towards the molecular core. This is the most
viable candidate for the embedded source originating the outflow and maser
phenomenology. The picture emerging from these and previous data shows the
extreme complexity of a small (< 0.5 pc) star-forming region where widely
different stages of stellar evolution are present.Comment: 15 pages, 16 figures, to be published in Astronomy & Astrophysic
New light on the S235A-B star forming region
The S235A-B star forming region has been extensively observed in the past
from the radio to the near-IR, but what was happening in the immediate
surroundings of the water maser, placed in between the two nebulosities, was
still unclear because of insufficient resolution especially in the spectral
range from the Far-IR to the mm, even though there were sound indications that
new young stellar objects (YSOs) are being formed there. We present here new
high resolution maps at mm wavelengths in different molecules (HCO+, C34S,
H2CS, SO2 and CH3CN), as well as in the 1.2 and 3.3 mm continuum obtained with
the Plateau de Bure interferometer, and JCMT observations at 450 micron and 850
micron that unambiguously reveal the presence of new YSOs placed in between the
two HII regions S235A and S235B and associated with the water maser. A
molecular core and an unresolved source in the mm and in the sub-mm are centred
on the maser, with indication of mass infall onto the core. Two molecular
bipolar outflows and a jet originate from the same position. Weak evidence is
found for a molecular rotating disk perpendicular to the direction of the main
bipolar outflow. The derived parameters indicate that one of the YSOs is an
intermediate luminosity object (L~1000 Lsun) in a very early evolutionary
phase, embedded in a molecular core of ~100 Msun, with a temperature of 30 K.
The main source of energy for the YSO could come from gravitational infall,
thus making of this YSO a rare example of intermediate luminosity protostar
representing a link between the earliest evolutionary phases of massive stars
and low mass protostars of class 0-I.Comment: 19 pages, 22 figures, to be published in Astronomy & Astrophysic
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Rio das Pedras. A Toolbox for Community Improvement
This report is the product of a semester-long urban planning studio focused on the informal settlement of Rio das Pedras in Rio de Janeiro, Brazil. Our client, Studio-X Rio commissioned this studio as part a 'Rio das Pedras Initiative' to examine and characterize this community and put forth proposals for its advancement within the realm of urban planning. The result is an extensive exploration of the present economy, living conditions, and culture of Rio das Pedras and its role within the city of Rio de Janeiro, through the eyes of the stakeholders involved in shaping the community
Perinatal and Socioeconomic Risk Factors for Variable and Persistent Cognitive Delay at 24 and 48 Months of Age in a National Sample
The objective of this paper is to examine patterns of cognitive delay at 24 and 48 months and quantify the effects of perinatal and sociodemographic risk factors on persistent and variable cognitive delay. Using data from 7,200 children in the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), multiple logistic regression models identified significant predictors of low cognitive functioning at 24 and 48 months. Additional multiple logistic models predicting cognitive delay at 48 months were estimated separately for children with and without delay at 24 months. Of the nearly 1,000 children delayed at 24 months, 24.2% remained delayed by 48 months; 7.9% of the children not delayed at 24 months exhibited delay at 48 months. Low and very low birthweight increased cognitive delay risk at 24, but not 48 months. Low maternal education had a strongly increasing effect (OR = 2.3 at 24 months, OR = 13.7 at 48 months), as did low family income (OR = 1.4 at 24 months, OR = 7.0 at 48 months). Among children delayed at 24 months, low maternal education predicted delay even more strongly at 48 months (OR = 30.5). Low cognitive functioning is highly dynamic from 24 to 48 months. Although gestational factors including low birthweight increase children’s risk of cognitive delay at 24 months, low maternal education and family income are more prevalent in the pediatric population and are much stronger predictors of both persistent and emerging delay between ages 24 and 48 months
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