A Review of the Interstate Park, Wisconsin Bison Find

In the fall of 1936, members of a C.C.C. Company engaged in excavating a ditch, uncovered the partial remains of several extinct bison in Interstate Park in Northwestern Wisconsin, about 40 miles northeast of St. Paul. The site, located in Polk County and known locally as Mountain Meadow, was a former peat bog situated in an area of drift deposited by the Grantsburg sublobe of the Keewatin ice sheet. The drift has been mapped as Mankato. The find was reported immediately to Dr. Alonzo Pond, an archeologist formerly of Beloit College, who at the time was connected with the National Park Service. Recognizing the possible importance of the discovery, Dr. Pond established an archeological dig under very difficult field conditions. The site was subject to an inflow of water which required the use of hip boots and pumps. Approximately 300 odd bones were discovered at a depth of three to four feet in the peat and close to the bottom of the bog. Three artifacts were also uncovered during the excavation. Unfortunately, they were discovered and removed during Dr. Pond\u27s absence and against his standing orders, apparently to save them from abnormal floodwater conditions

Ibex lowensis, First Evidence of Fossil Goat in North America

One of the problems dealing with the migration of Quaternary Bovid stocks from Eurasia to North America via the Bering Straits, is the extreme fragmentary nature of the fossil record. A number of the dozen or so genera now recognized have been established on the basis of single fragmentary specimens. Many times these consist of isolated bone fragments such as horncores, partial crania, dentitions and even less diagnostic elements of the axial skeleton. As recently as 193 7 species of two genera mw to the North American continent were identified from Alaskan deposits on the basis of similar fragmentary remains ( l) . It is with considerable interest, therefore, that the occurrence of a member of the goat group (genus Capra), previously unknown to the American scene, is described from the Quaternary of Iowa. The specimen in question, represented by a partial cranium with horncores, appears to be that of a fossil Ibex

Photocurrent response from vertically aligned single-walled carbon nanotube arrays

Vertically-aligned arrays of single walled carbon nanotubes were created on an optically transparent electrode (FTO glass) these arrays were found to exhibit a prompt current and voltage when exposed to light. These cells were then investigated by electrochemical impedance spectroscopy and found to exhibit a dampening of the recombination reaction over the first 24 hours. Symmetrical cell modeling was successful in simulating the behavior of normal cell architecture

On the Spatial Distribution of Stellar Populations in the Large Magellanic Cloud

We measure the angular correlation function of stars in a region of the Large Magellanic Cloud (LMC) that spans 2 degrees by 1.5 degrees. We find that the correlation functions of stellar populations are represented well by exponential functions of the angular separation for separations between 2 and 40 arcmin (corresponding to ~ 30 pc and 550 pc for an LMC distance of 50 kpc). The inner boundary is set by the presence of distinct, highly correlated structures, which are the more familiar stellar clusters, and the outer boundary is set by the observed region's size and the presence of two principal centers of star formation within the region. We also find that the normalization and scale length of the correlation function changes systematically with the mean age of the stellar population. The existence of positive correlation at large separations (~300 pc), even in the youngest population, argues for large-scale hierarchical structure in current star formation. The evolution of the angular correlation toward lower normalizations and longer scale lengths with stellar age argues for the dispersion of stars with time. We show that a simple, stochastic, self-propagating star formation model is qualitatively consistent with this behavior of the correlation function.Comment: 30 pages, 13 Figures. Scheduled for publication in AJ in June 199

A UK survey exploring the assistant practitioner role across diagnostic imaging: current practice, relationships and challenges to progression

YesObjective: Skill mix has been established as one method of maintaining imaging service delivery, with vertical and horizontal substitution of roles and tasks. Assistant practitioners (APs) have been undertaking limited imaging practice for almost two decades, but there remains a paucity of evidence related to the impact of their roles. Methods: This article reports on an electronic survey of individual APs within the NHS in the UK to explore utilisation, role scope and aspirations. Results: Responses were analysed from APs (n = 193) employed in 97 different organisations across the UK. The majority work in general radiography or mammography, with very few responses from other imaging modalities. Training routes varied across modalities, with most achieving Band 4 under Agenda for Change on completion of education. Limitations on practice vary between organisations and modalities, with many reporting blurring of the radiographer-AP boundary. Many aspire to continue their training to achieve registrant radiographer status, although there were clear frustrations from respondents over the lack of overt career prospects. Conclusion: Integration of the role into imaging department practice does not appear to be universal or consistent and further research is required to examine the optimal skill mix composition. Advances in knowledge: Skill mix implementation is inconsistent across modalities and geography in the UK. Opportunities for further workforce utilisation and expansion are evident

Assistant radiographer practitioners: Creating capacity or challenging professional boundaries?

YesIntroduction Over the last 2 decades the assistant radiographer practitioner (ARP) role has been introduced into NHS diagnostic imaging departments as a strategy to expand the workforce and create capacity. This skill mix initiative has not been implemented in a standardised way and there is limited knowledge of the current role scope within general radiography (X-Ray). Method An electronic survey of ARPs working within UK diagnostic imaging departments was conducted. Both open and closed questions sought information regarding basic demographic data (age category; gender; geographic region), scope of practice (patient groups; anatomical regions; imaging outside of the diagnostic imaging department), limitations placed on practice, supervision and additional roles. Results A total of 108 responses, including 13 trainees, were received. Most sites employ three or less ARPs in general radiography (n = 43/66; 65.2%), although 11 sites have five (range 1–15). The majority undertake imaging of both adults and children (n = 85/108; 78.7%), although limitations on age were described. Their scope of practice covers a broad anatomical range and included some non-ambulant patients. The level of supervision varied with some sites empowering ARPs to check the referral prior to examination (n = 25) or images post acquisition (n = 32) (both n = 20/66; χ2 = 16.003; 1df; p = 0.000). Conclusion ARPs are helping to maintain capacity in imaging departments but we suggest there is further scope for expansion. The practice described by the post holders suggests that many are working beyond the scope envisaged by the radiography professional body

Transient Gamma Ray Spectrometer Measurements of Gamma-Ray Lines from Novae. II. Constraining the Galactic Nova Rate from a Survey of the Southern Sky during 1995-1997

The good energy resolution (3--4 keV FWHM) of the Transient Gamma Ray Spectrometer (TGRS) on board the WIND spacecraft makes it sensitive to Doppler-shifted outbursts of 511 keV electron-positron annihilation radiation, the reason being that the Doppler shift causes the cosmic line to be slightly offset from a strong instrumental background 511 keV line at rest, which is ubiquitous in space environments. Such a cosmic line (blueshifted) is predicted to arise in classical novae due to the annihilation of positrons from $\beta$-decay on a timescale of a few hours in an expanding envelope. A further advantage of TGRS - its broad field of view, containing the entire southern ecliptic hemisphere - has enabled us to make a virtually complete and unbiased 3-year search for classical novae at distances up to ~1 kpc. We present negative results of this search, and estimate its implications for the highly-uncertain Galactic classical nova rate and for future space missions.Comment: 22 pp. + 3 fig

Order induced by dipolar interactions in a geometrically frustrated antiferromagnet

We study the classical Heisenberg model for spins on a pyrochlore lattice interacting via long range dipole-dipole forces and nearest neighbor exchange. Antiferromagnetic exchange alone is known not to induce ordering in this system. We analyze low temperature order resulting from the combined interactions, both by using a mean-field approach and by examining the energy cost of fluctuations about an ordered state. We discuss behavior as a function of the ratio of the dipolar and exchange interaction strengths and find two types of ordered phase. We relate our results to the recent experimental work and reproduce and extend the theoretical calculations on the pyrochlore compound, Gd$_2$Ti$_2$O$_7$, by Raju \textit{et al.}, Phys. Rev. B {\bf 59}, 14489 (1999).Comment: 5 pages, 5 figures, AMSLaTe

Transient Gamma Ray Spectrometer Measurements of Gamma-Ray Lines from Novae. I. Limits on the Positron Annihilation Line in Five Individual Novae

The Transient Gamma Ray Spectrometer (TGRS) on board the WIND spacecraft has spent most of the interval 1995-1997 in a high-altitude orbit where gamma-ray backgrounds are low. Its high-resolution Ge spectrometer is thus able to detect weak lines which are slightly offset from stronger background features. One such line is predicted from nucleosynthesis in classical novae, where beta-decays on a time-scale of a few hours in an expanding envelope produce positrons that annihilate to generate a line which is blueshifted by a few keV away from the background annihilation line at 511 keV. The broad TGRS field of view contained five known Galactic novae during 1995 January - 1997 June, and we have searched the spectra taken around the times of these events for the blueshifted nova annihilation line. Although no definite detections were made, the method is shown to be sensitive enough to detect novae occurring on ONeMg-rich white dwarfs out to about 2.5 kpc.Comment: 27 pp. + 10 figs., or offprint mailed by request to [email protected]