722 research outputs found
The Fine Line Between Normal and Starburst Galaxies
Recent literature suggests that there are two modes through which galaxies
grow their stellar mass - a normal mode characterized by quasi-steady star
formation, and a highly efficient starburst mode possibly triggered by
stochastic events such as galaxy mergers. While these differences are
established for extreme cases, the population of galaxies in-between these two
regimes is poorly studied and it is not clear where the transition between
these two modes of star formation occurs. We utilize ALMA observations of the
CO J=3-2 line luminosity in a sample of 20 infrared luminous galaxies that lie
in the intermediate range between normal and starburst galaxies at z ~ 0.25-0.6
in the COSMOS field to examine the gas content and star formation efficiency of
these galaxies. We compare these quantities to the galaxies' deviation from the
well-studied "main sequence" correlation between star formation rate and
stellar mass (MS) and find that at log() < 0.6, a galaxy's
distance to the main sequence is mostly driven by increased gas content, and
not a more efficient star formation process.Comment: 21 pages, 10 figure
Emerging approaches to measure photosynthesis from the leaf to the ecosystem
Measuring photosynthesis is critical for quantifying and modeling leaf to regional scale productivity of managed and natural ecosystems. This review explores existing and novel advances in photosynthesis measurements that are certain to provide innovative directions in plant science research. First, we address gas exchange approaches from leaf to ecosystem scales. Leaf level gas exchange is a mature method but recent improvements to the user interface and environmental controls of commercial systems have resulted in faster and higher quality data collection. Canopy chamber and micrometeorological methods have also become more standardized tools and have an advanced understanding of ecosystem functioning under a changing environment and through long time series data coupled with community data sharing. Second, we review proximal and remote sensing approaches to measure photosynthesis, including hyperspectral reflectance- A nd fluorescence-based techniques. These techniques have long been used with aircraft and orbiting satellites, but lower-cost sensors and improved statistical analyses are allowing these techniques to become applicable at smaller scales to quantify changes in the underlying biochemistry of photosynthesis. Within the past decade measurements of chlorophyll fluorescence from earth-orbiting satellites have measured Solar Induced Fluorescence (SIF) enabling estimates of global ecosystem productivity. Finally, we highlight that stronger interactions of scientists across disciplines will benefit our capacity to accurately estimate productivity at regional and global scales. Applying the multiple techniques outlined in this review at scales from the leaf to the globe are likely to advance understanding of plant functioning from the organelle to the ecosystem
Sea Star Wasting Disease in \u3cem\u3eAsterias forbesi\u3c/em\u3e along the Atlantic Coast of North America
As keystone species, sea stars serve to maintain biodiversity and species distribution through trophic level interactions in marine ecosystems. Recently, Sea Star Wasting Disease (SSWD) has caused widespread mass mortality in several sea star species from the Pacific Coast of the United States of America (USA) and Asterias forbesi on the Atlantic Coast. A densovirus, named Sea Star associated Densovirus (SSaDV), has been associated with the wasting disease in Pacific Coast sea stars, and limited samples of A. forbesi. The goal of this research is to examine the pathogenesis of SSWD in A. forbesi on the Atlantic Coast of the USA and to determine if SSaDV is associated with the wasting disease in this species. Histological examination of A. forbesi tissues affected with SSWD showed cuticle loss, vacuolation and necrosis of epidermal cells, and oedema of the dermis, but no consistent evidence indicating the cause of the lesions. Challenge experiments by cohabitation and immersion in infected water suggest that the cause of SSWD is viral in nature, as filtration (0.22 μm) of water from tanks with sea stars exhibiting SSWD did not prevent the transmission and progression of the disease. Death of challenged sea stars occurred 7–10 d after exposure to infected water or sea stars, and the infectivity crossed species (A. forbesi and Pateria miniata) with equal penetrance. Of the 48 stars tested by quantitative real time PCR, 29 (60%) were positive for the SSaDV VP1 gene. These stars represent field-collected sea stars from all geographical regions (South Carolina to Maine) in 2012–2015, as well as stars exposed to infected stars or water from affected tanks. However, a clear association between the presence of SSaDV and SSWD signs in experimental and field-collected A. forbesi was not found in this study
A review of transformative strategies for climate mitigation by grasslands
Grasslands can significantly contribute to climate mitigation. However, recent trends indicate that human activities have switched their net cooling effect to a warming effect due to management intensification and land conversion. This indicates an urgent need for strategies directed to mitigate climate warming while enhancing productivity and efficiency in the use of land and natural (nutrients, water) resources. Here, we examine the potential of four innovative strategies to slow climate change including: 1) Adaptive multi-paddock grazing that consists of mimicking how ancestral herds roamed the Earth; 2) Agrivoltaics that consists of simultaneously producing food and energy from solar panels on the same land area; 3) Agroforestry with a reverse phenology tree species, Faidherbia (Acacia) albida, that has the unique trait of being photosynthetically active when intercropped herbaceous plants are dormant; and, 4) Enhanced Weathering, a negative emission technology that removes atmospheric CO2 from the atmosphere. Further, we speculate about potential unknown consequences of these different management strategies and identify gaps in knowledge. We find that all these strategies could promote at least some of the following benefits of grasslands: CO2 sequestration, non-CO2 GHG mitigation, productivity, resilience to climate change, and an efficient use of natural resources. However, there are obstacles to be overcome. Mechanistic assessment of the ecological, environmental, and socio-economic consequences of adopting these strategies at large scale are urgently needed to fully assess the potential of grasslands to provide food, energy and environmental security
Pineocytoma with diffuse dissemination to the leptomeninges
Pineal parenchymal tumors are rare. Of the three types of pineal parenchymal tumors, pineocytomas are the least aggressive and are not known to diffusely disseminate. In this paper, we report the successful treatment of a case of pineocytoma with diffuse leptomeningeal relapse following initial stereotactic radiotherapy. A 39-year-old female presented with headaches, balance impairment, urinary incontinence, and blunted affect. A pineal mass was discovered on magnetic resonance imaging (MRI). A diagnosis of pineocytoma was established with an endoscopic pineal gland biopsy, and the patient received stereotactic radiotherapy. Ten years later, she developed diffuse leptomeningeal dissemination. The patient was then successfully treated with craniospinal radiation therapy. Leptomeningeal spread may develop as late as 10 years after initial presentation of pineocytoma. Our case demonstrates the importance of long-term follow-up of patients with pineal parenchymal tumors following radiation therapy, and the efficacy of craniospinal radiation in the treatment of leptomeningeal dissemination
A collaborative approach to combining service, teaching, and research
Objective. To describe a faculty-student collaborative model and its outcomes on teaching, service, and scholarship.
Design. A Medicare Part D elective course was offered that consisted of classroom and experiential learning where pharmacy students participated in community outreach events to assist Medicare beneficiaries with Part D plan selection. The course training was expanded to include medication therapy management (MTM) and the administration of immunizations. At the completion of the course, students collaborated with faculty members on research endeavors.
Evaluation. During the first 6 years of this course, the class size more than doubled from 20 to 42 students, and all students participating in the course met the IPPE requirements for community outreach. Over that same period, the number of beneficiaries receiving assistance with their Part D plan grew from 72 to 610; and with the help of students starting in 2011, faculty members had 28 poster presentations at national conferences, 7 invited podium presentations at national/international meetings, and published 8 manuscripts in peer-reviewed journals.
Conclusion. Through collaborative efforts, this model took an elective course and provided classroom and experiential learning for students, needed health services for the community, and opportunities to pursue wide ranging research projects for faculty members and students
Selective inhibition of protein secretion by abrogating receptor–coat interactions during ER export
Protein secretion is an essential process that drives cell growth, movement, and commu-nication. Protein traffic within the secretory pathway occurs via transport intermediatesthat bud from one compartment and fuse with a downstream compartment to delivertheir contents. Here, we explore the possibility that protein secretion can be selectivelyinhibited by perturbing protein–protein interactions that drive capture into transportvesicles. Human proprotein convertase subtilisin/kexin type 9 (PCSK9) is a determi-nant of cholesterol metabolism whose secretion is mediated by a specific cargo adaptorprotein, SEC24A. We map a series of protein–protein interactions between PCSK9, itsendoplasmic reticulum (ER) export receptor SURF4, and SEC24A that mediate secre-tion of PCSK9. We show that the interaction between SURF4 and SEC24A can beinhibited by 4-phenylbutyrate (4-PBA), a small molecule that occludes a cargo-bindingdomain of SEC24. This inhibition reduces secretion of PCSK9 and additional SURF4clients that we identify by mass spectrometry, leaving other secreted cargoes unaffected.We propose that selective small-molecule inhibition of cargo recognition by SEC24 is apotential therapeutic intervention for atherosclerosis and other diseases that are modu-lated by secreted proteins
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