Skin impressions from the tail region of an indeterminate hadrosaur recently excavated from the Upper Cretaceous Ringbone Formation, southwest New Mexico represent the first known dinosaur specimen ...from New Mexico with impressions of the integument preserved in association with skeletal remains. The mid- to distal-caudal region is represented by 20 articulated centra, other disarticulated centra, a single chevron, ossified tendons and fragmentary bone, including poorly preserved neural spines. The skin impressions are preserved in negative and positive relief between two very fine-grained sandstone beds, interpreted as part of a fluvio-lacustrine facies package. The impression surface is directly below the ossified tendons, and 2.5 m from the articulated vertebral column.
The skin impressions are six discrete patches characterized by predominantly apical, circular to ovate tubercles. Measurements of the long and short axes of individual tubercles demonstrate that a distribution of relatively homogenous tubercle sizes occur along the tail section. The tubercles range from 3 to 12 mm and 10 to 16 mm on the short and long axes, respectively. All tubercles examined are ornamented with radiating ridges and grooves that converge at their apex. Presently, the material cannot be identified below the level of Hadrosauridae; however, a comparison of tubercle size, shape and ornamentation described previously from hadrosaur skin impressions indicates the integument morphology of the Ringbone hadrosaur has some similarities to that of the gryposaurs.
In general, the complexity of the radial sculpturing, specifically the number of ridges and rugosity, increases with increasing tubercle size. This specific type of ornamentation is not known from modern reptiles or birds; however, the tubercular morphology is similar to that of the lizard Heloderma. Although it is impossible to determine whether the ridges and grooves may have had a physiologic function, these features would increase the surface area of the skin, and therefore may have afforded more efficient heat exchange across the skin, or possibly provided added resistance to tearing and puncturing.
The GIOS program has conducted HF scatter and ionosphere propagation tests to show that a single HF transmitter can illuminate greater than 1000 km of ocean surface and scatter waves to single ...satellite in low earth orbit. The receiver in orbit samples the HF illuminated area to measure Brag scatter from the ocean with signals that pass through the ionosphere. The Doppler shifts and group delays map to specific points on the ocean surface at each point in the satellite orbit. Using the theory of ocean scatter, both coherent (specular) and incoherent (Bragg) scatter components at HF frequency provides bistatic sampling of global ocean surface. Data based models of the waveheight spectrum have been used in simulations to validate this concept. Experimental tests with the HF transmitter of ROTHR/VA and space based receiver of ePOP/RRI have provided data that were collected in April 2015. Actual interpretation in of the satellite measurements in terms of ocean surface parameters is in progress. A practical GIOS system will require measurements from a spacecraft flying below the ionosphere. For this purpose, the Naval Research Laboratory has designed a satellite called CARINA which will orbit the earth at an altitude of 200 to 250 km for 60 days.
The Body Temperature of Tyrannosaurus rex Millard, Andrew R.; Barrick, Reese E.; Showers, William J. ...
Science,
03/1995, Letnik:
267, Številka:
5204
Journal Article
Recenzirano
Odprti dostop
Millard comments on the research of the body temperature of Tyrannosaurus rex, conducted by Barrick et al, and concludes that T. rex is an ectotherm. Barrick et al voice their disagreement with ...Millard's conclusion.
HIV Protocols Michael, Nelson; Kim, Jerome H
1999, 1999., Letnik:
17
eBook
In HIV Protocols, Nelson Michael and Jerome Kim have organized a collection of cutting-edge techniques essential for studying the molecular biology, virology, and immunology of the HIV virus. The ...methods cover a broad range of research interests, including quantitation of viral genomes, HIV promoter function, B-cell epitope mapping, viral coreceptor usage, and measurements of T-cell function. Special emphasis is accorded to the study of those viral and host immune responses to infection that will be critical to the design of effective preventive vaccines. HIV Protocols is the first HIV methods book to concentrate equally on virology, molecular biology, and immunology, as well as to incorporate methods on chemokine receptor structure and function. Comprehensive and state-of-the-art, the techniques detailed here provide an indispensable framework for unraveling the molecular and immunological aspects of HIV infection.
The observation of sub-grained cellular features in additively manufactured (AM)/selectively laser melted (SLM) 316L stainless steel components has remained an interesting, though incompletely ...understood phenomenon. However, the recently observed correlation linking the presence of these features with significantly enhanced mechanical strength in SLM 316L materials has driven a renewed interest and effort toward elucidating the mechanism(s) by which they are formed. To date, the dominant hypothesis, cellular solidification followed by dislocation-solute entanglement, remains incompatible with the ensemble of reported observations from multiple independent studies. This effort offers direct evidence of a previously unrecognized interaction of phenomena, that, when acting in concert, give rise to this commonly observed substructure. These phenomena include SLM-induced intrinsic strain-aging, Cottrell atmosphere formation, and twin-boundary enhanced mass diffusion to structural defects.
Satellite ammonia (NH3) observations provide unprecedented insights into NH3 emissions, spatiotemporal variabilities and trends, but validation with in-situ measurements remains lacking. Here, total ...columns from the Infrared Atmospheric Sounding Interferometer (IASI) were intercompared to boundary layer NH3 profiles derived from aircraft- and surface-based measurements primarily in Colorado, USA, in the summer of 2014. IASI-NH3 version 3 near real-time dataset compared well to in-situ derived columns (windows ±15 km around centroid, ±1 hour around overpass time) with a correlation of 0.58, a slope of 0.78±0.14, and an intercept of 2.1×10(exp 15)±1.5×10(exp 15) molecules cm(exp -2) . Agreement degrades at larger spatiotemporal windows, consistent with the short atmospheric lifetime of NH3. We also examined IASI version 3R data, which relies on temperature retrievals from the ERA Reanalysis, and a third product generated using aircraft-measured temperature profiles. The overall agreement improves slightly for both cases, and neither is biased within their combined measurement errors. Thus, spatiotemporal averaging of IASI over large windows can be used to reduce retrieval noise. Nonetheless, sampling artifacts of airborne NH3 instruments result in significant uncertainties of the in-situ-derived columns. For example, large validation differences exist between ascent and descent profiles, and the assumptions of the free tropospheric NH3 profiles used above the aircraft ceiling significantly impact the validation. Because short-lived species like NH3 largely reside within the boundary layer with complex vertical structures, more comprehensive validation is needed across a wide range of environments. More accurate and widespread in-situ NH3 datasets are therefore required for improved validations of satellite products.
The Agricultural Technical Schools (ATS) of Egypt were designed to prepare skilled workers for the agricultural economy. A project funded by USAID through the Midwest Universities Consortium for ...International Activities (MUCIA) was designed to prepare ATS instructors for incorporating supervised agricultural internships and agribusiness decision–making skills into their curricula. Workshops were presented, with assistance from university faculty in Egypt, on topics including planning, conducting and evaluating internships, and on selected agribusiness competencies that were relevant to ATS programs. Workshop participants rated the workshops and materials very highly. The ATS instructors also indicated that their competency in teaching the topics had increased as a result of the workshops. The instructors indicated other topics that future workshops could address. The researchers identified a series of lessons learned about conducting workshops in a foreign country and offered recommendations to assist other U.S. faculty in getting involved in international development projects.
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