508 research outputs found
Museum collections: Natural history training bridges time, space, and digital platforms.
Natural history collections offer a number of unique physical and virtual opportunities to create formal and informal progressive learning environments. Collections provide direct interaction with biodiversity as it changes through time and space. Collections-based experiences lead to an increased understanding and substantive interaction with the living world. Recent studies demonstrate how nature and outdoor experiences can improve learning. We discuss how collections, and the data associated with collections, are a critical component linking nature and scientific inquiry. Partnerships that develop around collections and collections-based science can foster innovative educational and research experiences that are enhanced by access to museum specimens. Such collaborations can also facilitate new avenues of learning through not only traditional classroom settings, but also citizen science initiatives, cross-disciplinary field experiences, or other place-based learning environments. We emphasize how the recent surge in specimen-based digitization initiatives has resulted in unprecedented access to a wealth of biodiversity information and how this vastly expands the reach of natural history collections. Natural history collections, the data they contain, and the emergences of digital databases enable scientists and the public to address global, regional, and local issues related to biodiversity that were simply unachievable a decade ago
Natural History Collections: Teaching About Biodiversity Across Time, Space, and Digital Platforms
Natural history collections offer unique physical and virtual opportunities for formal and informal progressive learning. Collections are unique data in that they each represent a biological record at a single place and time that cannot be obtained by any other method. Collections-based experiences lead to an increased understanding of and substantive interaction with the living world. Global biological diversity and changes in that diversity are directly tracked through specimens in collections, regardless of whether changes are ancient or recent. We discuss how collections, specimens, and the data associated with them, can be critical components linking nature and scientific inquiry. Specimens are the basic tools for educating students and interested citizens through direct or virtual contact with the diversity of collections. Such interactions include instruction in a formal classroom setting, volunteering to gather and curate collections, and informal presentations at coffee shops. We emphasize how the recent surge in specimen-based digitization initiatives has resulted in unprecedented access to a wealth of biodiversity information and how this availability vastly expands the reach of natural history collections. The emergence of online databases enables scientists and the public to utilize the specimens and associated data contained in natural history collections to address global, regional, and local issues related to biodiversity in a way that was unachievable a decade ago
Livestock grazing and vegetative filter strip buffer effects on runoff sediment, nitrate, and phosphorus losses
Livestock grazing in the Midwestern United States can result in significant levels of runoff sediment and nutrient losses to surface water resources. Some of these contaminants can increase stream eutrophication and are suspected of contributing to hypoxic conditions in the Gulf of Mexico. This research quantified effects of livestock grazing management practices and vegetative filter strip buffers on runoff depth and mass losses of total solids, nitrate-nitrogen (NO3-N), and ortho-phosphorus (PO4-P) under natural hydrologic conditions. Runoff data were collected from 12 rainfall events during 2001 to 2003 at an Iowa State University research farm in central Iowa, United States. Three vegetative buffers (paddock area:vegetative buffer area ratios of 1:0.2, 1:0.1, and 1:0 no buffer [control]) and three grazing management practices (continuous, rotational, and no grazing [control]) comprised nine treatment combinations (vegetative buffer ratio/grazing management practice) replicated in three 1.35 ha (3.34 ac) plot areas. The total 4.05 ha (10.02 ac) study area also included nine 0.4 ha (1.0 ac) paddocks and 27 vegetative buffer runoff collection units distributed in a randomized complete block design. The study site was established on uneven terrain with a maximum of 15% slopes and consisted of approximately 100% cool-season smooth bromegrass. Average paddock and vegetative buffer plant tiller densities estimated during the 2003 project season were approximately 62 million and 93 million tillers ha−1 (153 million and 230 million tillers ac−1), respectively. Runoff sample collection pipe leakage discovered and corrected during 2001 possibly reduced runoff depth and affected runoff contaminant mass losses data values. Consequently, 2001 runoff analysis results were limited to treatment comparisons within the 2001 season and were not compared with 2002 and 2003 data. Analysis results from 2001 showed no significant differences in average losses of runoff, total solids, NO3-N, and PO4-P among the nine vegetative buffer/grazing practice treatment combinations. Results from 2002 indicated significantly higher losses of runoff and total solids from 1:0 no buffer/rotational grazing and 1:0 no buffer/continuous grazing treatment combination plots, respectively, compared among other 2002 season treatment combinations. The 2003 results showed significantly higher runoff and total solids losses from 1:0 no buffer/no grazing treatment combination plots compared among all 2003 treatment combinations and from 1:0.1 vegetative buffer/no grazing treatment combination plots compared among all 2003 treatment combinations and with respective 2002 treatment combinations. However, the 2003 results indicated effective vegetative buffer performance with significantly lower runoff, total solids, and NO3-N losses from the larger 1:0.2 buffer area compared among the smaller 1:0.1 buffer area and 1:0 no buffer treatment combinations. The 2003 results also indicated a highly significant increase in losses of NO3-N from 1:0.1 buffer/no grazing treatment combination plots compared among other 2003 season treatment combinations and with respective 2002 treatment combinations. Overall results from this study suggest a shift from significantly higher 2002 season plot losses of continuous and rotational grazing treatment combinations to significantly higher 2003 season losses of no grazing treatment combinations. We speculate this shift to significantly higher runoff and contaminant losses from no grazing treatment combination plots during 2003 reflects the variability inherent to a complex and dynamic soil-water environment of livestock grazing areas. However, we also hypothesize the environmental conditions that largely consisted of a dense perennial cool-season grass type, high-relief landscape, and relatively high total rainfall depth may not necessarily include livestock grazing activities
Phosphorylation State of Olig2 Regulates Proliferation of Neural Progenitors
SummaryThe bHLH transcription factors that regulate early development of the central nervous system can generally be classified as either antineural or proneural. Initial expression of antineural factors prevents cell cycle exit and thereby expands the pool of neural progenitors. Subsequent (and typically transient) expression of proneural factors promotes cell cycle exit, subtype specification, and differentiation. Against this backdrop, the bHLH transcription factor Olig2 in the oligodendrocyte lineage is unorthodox, showing antineural functions in multipotent CNS progenitor cells but also sustained expression and proneural functions in the formation of oligodendrocytes. We show here that the proliferative function of Olig2 is controlled by developmentally regulated phosphorylation of a conserved triple serine motif within the amino-terminal domain. In the phosphorylated state, Olig2 maintains antineural (i.e., promitotic) functions that are reflected in human glioma cells and in a genetically defined murine model of primary glioma
Safety and Feasibility of High-pressure Transvenous Limb Perfusion With 0.9% Saline in Human Muscular Dystrophy
We evaluated safety and feasibility of the transvenous limb perfusion gene delivery method in muscular dystrophy. A dose escalation study of single limb perfusion with 0.9% saline starting with 5% of limb volume was carried out in adults with muscular dystrophies under intravenous analgesia/anesthesia. Cardiac, vascular, renal, muscle, and nerve functions were monitored. A tourniquet was placed above the knee with inflated pressure of 310 mm Hg. Infusion was carried out with a clinically approved infuser via an intravenous catheter inserted in the saphenous vein with a goal infusion rate of 80 ml/minute. Infusion volume was escalated stepwise to 20% limb volume in seven subjects. No subject complained of any post procedure pain other than due to needle punctures. Safety warning boundaries were exceeded only for transient depression of limb tissue oximetry and transient elevation of muscle compartment pressures; these were not associated with nerve, muscle, or vascular damage. Muscle magnetic resonant imaging (MRI) demonstrated fluid accumulation in muscles of the perfused lower extremity. High-pressure retrograde transvenous limb perfusion with saline up to 20% of limb volume at above infusion parameters is safe and feasible in adult human muscular dystrophy. This study will serve as a basis for future gene transfer clinical trials
Adipose energy stores, physical work, and the metabolic syndrome: lessons from hummingbirds
Hummingbirds and other nectar-feeding, migratory birds possess unusual adaptive traits that offer important lessons concerning obesity, diabetes and the metabolic syndrome. Hummingbirds consume a high sugar diet and have fasting glucose levels that would be severely hyperglycemic in humans, yet these nectar-fed birds recover most glucose that is filtered into the urine. Hummingbirds accumulate over 40% body fat shortly before migrations in the spring and autumn. Despite hyperglycemia and seasonally elevated body fat, the birds are not known to become diabetic in the sense of developing polyuria (glucosuria), polydipsia and polyphagia. The tiny (3–4 g) Ruby-throated hummingbird has among the highest mass-specific metabolic rates known, and loses most of its stored fat in 20 h by flying up to 600 miles across the Gulf of Mexico. During the breeding season, it becomes lean and maintains an extremely accurate energy balance. In addition, hummingbirds can quickly enter torpor and reduce resting metabolic rates by 10-fold. Thus, hummingbirds are wonderful examples of the adaptive nature of fat tissue, and may offer lessons concerning prevention of metabolic syndrome in humans
High-Pressure Transvenous Perfusion of the Upper Extremity in Human Muscular Dystrophy: A Safety Study with 0.9% Saline
We evaluated safety and feasibility of high-pressure transvenous limb perfusion in an upper extremity of adult patients with muscular dystrophy, after completing a similar study in a lower extremity. A dose escalation study of single-limb perfusion with 0.9% saline was carried out in nine adults with muscular dystrophies under intravenous analgesia. Our study demonstrates that it is feasible and definitely safe to perform high-pressure transvenous perfusion with 0.9% saline up to 35% of limb volume in the upper extremities of young adults with muscular dystrophy. Perfusion at 40% limb volume is associated with short-lived physiological changes in peripheral nerves without clinical correlates in one subject. This study provides the basis for a phase 1/2 clinical trial using pressurized transvenous delivery into upper limbs of nonambulatory patients with Duchenne muscular dystrophy. Furthermore, our results are applicable to other conditions such as limb girdle muscular dystrophy as a method for delivering regional macromolecular therapeutics in high dose to skeletal muscles of the upper extremity
Changes in reflectin protein phosphorylation are associated with dynamic iridescence in squid
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of The Royal Society for personal use, not for redistribution. The definitive version was published in Journal of The Royal Society Interface 6 (2010): 549-560, doi:10.1098/rsif.2009.0299.Many cephalopods exhibit remarkable dermal iridescence, a component of their complex,
dynamic camouflage and communication. In the species Euprymna scolopes, the light-organ iridescence
is static and is due to reflectin protein-based platelets assembled into lamellar thin-film
reflectors called iridosomes, contained within iridescent cells called iridocytes. Squid in the
family Loliginidae appear to be unique in that the dermis possesses a dynamic iridescent component,
with reflective, colored structures that are assembled and disassembled under the control of
the muscarinic cholinergic system and the associated neurotransmitter acetylcholine (Mathger et
al. 2004). Here we present the sequences and characterization of three new members of the reflectin
family associated with the dynamically changeable iridescence in Loligo and not found in
static Euprymna iridophores. In addition, we show that application of genistein, a protein tyrosine
kinase inhibitor, suppresses acetylcholine- and calcium-induced iridescence in Loligo. We
further demonstrate that two of these novel reflectins are extensively phosphorylated in concert
with the activation of iridescence by exogenous acetylcholine. This phosphorylation and the correlated
iridescence can be blocked with genistein. Our results suggest that tyrosine phosphorylation
of reflectin proteins is involved in the regulation of dynamic iridescence in Loligo.We gratefully acknowledge support from Anteon contract F33615-03-D-5408 to the Marine
Biological Laboratory, Woods Hole, MA and grant # W911NF-06-1-0285 from the Army
Research Office to D.E.M
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