142 research outputs found
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Enabling Geographic Research Across Disciplines: Building an Institutional Infrastructure for Geographic Analysis at Harvard University
Founded in 1818, the Harvard Map Collection (HMC) is the oldest map collection in America, holding 400,000 maps, more than 6,000 atlases and thousands of reference books. HMC has a strong commitment to digital resources and manages the Harvard Geospatial Library, a foundation for geospatial data service at Harvard. The Center for Geographic Analysis at Harvard University (CGA) was founded in 2006, independent of the library system, to serve the entire university. This article presents the history, organizational structure, and operational model of CGA and HMC, reviews achievements, lessons learned, suggests future improvements, and reviews GIS-related medical research at Harvard.Other Research Uni
miR-200a Prevents Renal Fibrogenesis Through Repression of TGF-β2 Expression
OBJECTIVE: Progressive fibrosis in the diabetic kidney is driven and sustained by a diverse range of profibrotic factors. This study examines the critical role of microRNAs (miRNAs) in the regulation of the key fibrotic mediators, TGF-β1 and TGF-β2. RESEARCH DESIGN AND METHODS: Rat proximal-tubular epithelial cells (NRK52E) were treated with TGF-β1 and TGF-β2 for 3 days, and expression of markers of epithelial-to-mesenchymal transition (EMT) and fibrogenesis were assessed by RT-PCR and Western blotting. The expression of miR-141 and miR-200a was also assessed, as was their role as translational repressors of TGF-β signaling. Finally, these pathways were explored in two different mouse models, representing early and advanced diabetic nephropathy. RESULTS: Both TGF-β1 and TGF-β2 induced EMT and fibrogenesis in NRK52E cells. TGF-β1 and TGF-β2 also downregulated expression of miR-200a. The importance of these changes was demonstrated by the finding that ectopic expression miR-200a downregulated smad-3 activity and the expression of matrix proteins and prevented TGF-β-dependent EMT. miR-200a also downregulated the expression of TGF-β2, via direct interaction with the 3' untranslated region of TGF-β2. The renal expression of miR-141 and miR-200a was also reduced in mouse models representing early and advanced kidney disease. CONCLUSIONS: miR-200a and miR-141 significantly impact on the development and progression of TGF-β-dependent EMT and fibrosis in vitro and in vivo. These miRNAs appear to be intricately involved in fibrogenesis, both as downstream mediators of TGF-β signaling and as components of feedback regulation, and as such represent important new targets for the prevention of progressive kidney disease in the context of diabetes
Advanced Glycation End Product Interventions Reduce Diabetes-Accelerated Atherosclerosis
Advanced glycation end product (AGE) formation may contribute to the progression of atherosclerosis, particularly in diabetes. The present study explored atherosclerosis in streptozotocin-induced diabetic apolipoprotein E–deficient (apoE�/�) mice that were randomized (n � 20) to receive for 20 weeks no treatment, the AGE cross-link breaker ALT-711, or the inhibitor of AGE formation aminoguanidine (AG). A sixfold increase in plaque area with diabetes was attenuated by 30 % with ALT-711 and by 40 % in AG-treated mice. Regional distribution of plaque demonstrated no reduction in plaque area or complexity within the aortic arch with treatment, in contrast to the thoracic and abdominal aortas, where significant attenuation was seen. Diabetes-associated accumulation of AGEs in aorta
Carnegie Supernova Project-II: The Near-infrared Spectroscopy Program
Shifting the focus of Type Ia supernova (SN Ia) cosmology to the
near-infrared (NIR) is a promising way to significantly reduce the systematic
errors, as the strategy minimizes our reliance on the empirical
width-luminosity relation and uncertain dust laws. Observations in the NIR are
also crucial for our understanding of the origins and evolution of these
events, further improving their cosmological utility. Any future experiments in
the rest-frame NIR will require knowledge of the SN Ia NIR spectroscopic
diversity, which is currently based on a small sample of observed spectra.
Along with the accompanying paper, Phillips et al. (2018), we introduce the
Carnegie Supernova Project-II (CSP-II), to follow up nearby SNe Ia in both the
optical and the NIR. In particular, this paper focuses on the CSP-II NIR
spectroscopy program, describing the survey strategy, instrumental setups, data
reduction, sample characteristics, and future analyses on the data set. In
collaboration with the Harvard-Smithsonian Center for Astrophysics (CfA)
Supernova Group, we obtained 661 NIR spectra of 157 SNe Ia. Within this sample,
451 NIR spectra of 90 SNe Ia have corresponding CSP-II follow-up light curves.
Such a sample will allow detailed studies of the NIR spectroscopic properties
of SNe Ia, providing a different perspective on the properties of the unburned
material, radioactive and stable nickel produced, progenitor magnetic fields,
and searches for possible signatures of companion stars.Comment: 20 pages, 7 figures, accepted for publication in PAS
Carnegie Supernova Project-II: Extending the Near-Infrared Hubble Diagram for Type Ia Supernovae to
The Carnegie Supernova Project-II (CSP-II) was an NSF-funded, four-year
program to obtain optical and near-infrared observations of a "Cosmology"
sample of Type Ia supernovae located in the smooth Hubble flow (). Light curves were also obtained of a "Physics"
sample composed of 90 nearby Type Ia supernovae at selected for
near-infrared spectroscopic time-series observations. The primary emphasis of
the CSP-II is to use the combination of optical and near-infrared photometry to
achieve a distance precision of better than 5%. In this paper, details of the
supernova sample, the observational strategy, and the characteristics of the
photometric data are provided. In a companion paper, the near-infrared
spectroscopy component of the project is presented.Comment: 43 pages, 10 figures, accepted for publication in PAS
The Carnegie Supernova Project: First Near-Infrared Hubble Diagram to z~0.7
The Carnegie Supernova Project (CSP) is designed to measure the luminosity
distance for Type Ia supernovae (SNe Ia) as a function of redshift, and to set
observational constraints on the dark energy contribution to the total energy
content of the Universe. The CSP differs from other projects to date in its
goal of providing an I-band {rest-frame} Hubble diagram. Here we present the
first results from near-infrared (NIR) observations obtained using the Magellan
Baade telescope for SNe Ia with 0.1 < z < 0.7. We combine these results with
those from the low-redshift CSP at z <0.1 (Folatelli et al. 2009). We present
light curves and an I-band Hubble diagram for this first sample of 35 SNe Ia
and we compare these data to 21 new SNe Ia at low redshift. These data support
the conclusion that the expansion of the Universe is accelerating. When
combined with independent results from baryon acoustic oscillations (Eisenstein
et al. 2005), these data yield Omega_m = 0.27 +/- 0.0 (statistical), and
Omega_DE = 0.76 +/- 0.13 (statistical) +/- 0.09 (systematic), for the matter
and dark energy densities, respectively. If we parameterize the data in terms
of an equation of state, w, assume a flat geometry, and combine with baryon
acoustic oscillations, we find that w = -1.05 +/- 0.13 (statistical) +/- 0.09
(systematic). The largest source of systematic uncertainty on w arises from
uncertainties in the photometric calibration, signaling the importance of
securing more accurate photometric calibrations for future supernova cosmology
programs. Finally, we conclude that either the dust affecting the luminosities
of SNe Ia has a different extinction law (R_V = 1.8) than that in the Milky Way
(where R_V = 3.1), or that there is an additional intrinsic color term with
luminosity for SNe Ia independent of the decline rate.Comment: 44 pages, 23 figures, 9 tables; Accepted for publication in the
Astrophysical Journa
Carnegie Supernova Project II: The slowest rising Type Ia supernova LSQ14fmg and clues to the origin of super-Chandrasekhar/03fg-like events
The Type Ia supernova (SN Ia) LSQ14fmg exhibits exaggerated properties which
may help to reveal the origin of the "super-Chandrasekhar" (or 03fg-like)
group. The optical spectrum is typical of a 03fg-like SN Ia, but the light
curves are unlike those of any SNe Ia observed. The light curves of LSQ14fmg
rise extremely slowly. At -23 rest-frame days relative to B-band maximum,
LSQ14fmg is already brighter than =-19 mag before host extinction
correction. The observed color curves show a flat evolution from the earliest
observation to approximately one week after maximum. The near-infrared light
curves peak brighter than -20.5 mag in the J and H bands, far more luminous
than any 03fg-like SNe Ia with near-infrared observations. At one month past
maximum, the optical light curves decline rapidly. The early, slow rise and
flat color evolution are interpreted to result from an additional excess flux
from a power source other than the radioactive decay of the synthesized
. The excess flux matches the interaction with a typical superwind of
an asymptotic giant branch (AGB) star in density structure, mass-loss rate, and
duration. The rapid decline starting at around one month past B-band maximum
may be an indication of rapid cooling by active carbon monoxide (CO) formation,
which requires a low temperature and high density environment. These
peculiarities point to an AGB progenitor near the end of its evolution and the
core degenerate scenario as the likely explosion mechanism for LSQ14fmg.Comment: 22 pages, 15 figures, accepted for publication in Ap
SN 2012fr: Ultraviolet, Optical, and Near-infrared Light Curves of a Type Ia Supernova Observed within a Day of Explosion
We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from −12 to +140 days with respect to the epoch of B-band maximum (tBmax). Supplementary imaging at the earliest epochs reveals an initial slow and nearly linear rise in luminosity with a duration of ∼2.5 days, followed by a faster rising phase that is well reproduced by an explosion model with a moderate amount of 56Ni mixing in the ejecta. From our analysis of the light curves, we conclude that: (i) the explosion occurred 1800 Å) luminosity was 16.5 ± 0.6 days, (iii) the supernova suffered little or no host-galaxy dust reddening, (iv) the peak luminosity in both the optical and near-infrared was consistent with the bright end of normal Type Ia diversity, and (v) 0.60 ± 0.15 M⊙ of 56Ni was synthesized in the explosion. Despite its normal luminosity, SN 2012fr displayed unusually prevalent high-velocity Ca II and Si II absorption features, and a nearly constant photospheric velocity of the Si II λ6355 line at ∼12,000 km s-1 that began ∼5 days before tBmax. We also highlight some of the other peculiarities in the early phase photometry and the spectral evolution. SN 2012fr also adds to a growing number of Type Ia supernovae that are hosted by galaxies with direct Cepheid distance measurements.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat
Fertility preservation for female patients with childhood, adolescent, and young adult cancer:recommendations from the PanCareLIFE Consortium and the International Late Effects of Childhood Cancer Guideline Harmonization Group
Female patients with childhood, adolescent, and young adult cancer are at increased risk for fertility impairment when treatment adversely affects the function of reproductive organs. Patients and their families desire biological children but substantial variations in clinical practice guidelines reduce consistent and timely implementation of effective interventions for fertility preservation across institutions. As part of the PanCareLIFE Consortium, and in collaboration with the International Late Effects of Childhood Cancer Guideline Harmonization Group, we reviewed the current literature and developed a clinical practice guideline for fertility preservation in female patients who were diagnosed with childhood, adolescent, and young adult cancer at age 25 years or younger, including guidance on risk assessment and available methods for fertility preservation. The Grading of Recommendations Assessment, Development and Evaluation methodology was used to grade the available evidence and to form the recommendations. This clinical practice guideline leverages existing evidence and international expertise to develop transparent recommendations that are easy to use to facilitate the care of female patients with childhood, adolescent, and young adult cancer who are at high risk for fertility impairment. A complete review of the existing evidence, including a quality assessment, transparent reporting of the guideline panel's decisions, and achievement of global interdisciplinary consensus, is an important result of this intensive collaboration.info:eu-repo/semantics/publishe
A cross-sectional study of early identification of postpartum depression: Implications for primary care providers from The Ontario Mother & Infant Survey
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