Visible and near-infrared reflectance spectroscopy of the Yamato 980459 meteorite in comparison with some shergottites

Visible and near-infrared reflectance spectrum of a sample of Yamato (Y) 980459 meteorite has been measured. Preliminary analyses of the spectrum have been performed using the modified Gaussian model, and the results have been compared with those of similar analyses of some shergottites and tricomponent mixtures of olivine, pyroxene, and plagioclase. They suggest that Y980459 has lower Fe and/or Ca concentration in pyroxene phase except its high-Ca pyroxene having similar Fe/Ca concentration to EETA79001 (Lithology A), lower pyroxene abundance, and more glassy phase than those shergottite samples. An estimated pyroxene modal abundance of this Y980459 sample is 36±13%, which is consistent with another estimate of 48% by an independent petrographic study

Reflectance spectra of the Yamato 000593 nakhlite: Spectroscopic similarities to other nakhlites

Y000593 (Y) is a newly found nakhlite and its component minerals are augite (～80 vol% ), olivine (～10 vol% ) and mesostasis (～10 vol% ). We compare the reflectance spectrum of Y000593 with those of two other nakhlites, Nakhla and Lafayette. The reflectance spectrum of Y000593 is similar to that of Nakhla, and is also similar to Lafayette except for differences in slope from 0.6-0.8μm in wavelength. Reflectance spectra of all these nakhlites show two strong absorption bands around 1μm and 2μm due to augite. Their band minimum wavelengths were calculated using the polynomial fitting and the modified Gaussian model (MGM). Almost all of their band centers and band parameters were similar to one another, which is consistent with the mineralogical and petrological study of nakhlites

RESULTS OF EATON AND LITTLER'S LIGAMENT RECONSTRUCTION FOR INSTABILITY OF THE FIRST CARPOMETACARPAL JOINT

This study presents the cases of Eaton and Littler's ligament reconstruction for the treatment of instability of lst CM joint resulting from early stage osteoarthritis (Group OA), trauma (Group T), and a part of generalized joint laxity (Group GJL) in 21 joints of 20 cases. Omitting six cases with less than one year follow-up, 15 joints in 14 cases were analyzed. Clinically, hypermobility pain was improved in all joints. However, eight out of 14 patients felt their joints stretched, but still had the normal range of motion. Grip power and pinch power was significantly improved (P＜0.01, P＜0.05). Comparing each group, only Group T revealed a significant difference between preoperative and postoper- ative grip power (P＜0.01). In increase of grip power, Group T were more significantly improved than Group OA (P＜0.01) and Group GJL (P＜0.05). Radiographically, postoper- ative stages of 4 joints in 4 cases out of 8 cases which felt stretched progressed from their preoperative stages. We assumed that the newly reconstructed ligament may be strong enough to maintain the stability of 1st CM joint and ligament reconstruction is most effective in treating post-traumatic instability

RESULTS OF EATON AND LITTLER'S LIGAMENT RECONSTRUCTION FOR INSTABILITY OF THE FIRST CARPOMETACARPAL JOINT

This study presents the cases of Eaton and Littler's ligament reconstruction for the treatment of instability of lst CM joint resulting from early stage osteoarthritis (Group OA), trauma (Group T), and a part of generalized joint laxity (Group GJL) in 21 joints of 20 cases. Omitting six cases with less than one year follow-up, 15 joints in 14 cases were analyzed. Clinically, hypermobility pain was improved in all joints. However, eight out of 14 patients felt their joints stretched, but still had the normal range of motion. Grip power and pinch power was significantly improved (P＜0.01, P＜0.05). Comparing each group, only Group T revealed a significant difference between preoperative and postoper- ative grip power (P＜0.01). In increase of grip power, Group T were more significantly improved than Group OA (P＜0.01) and Group GJL (P＜0.05). Radiographically, postoper- ative stages of 4 joints in 4 cases out of 8 cases which felt stretched progressed from their preoperative stages. We assumed that the newly reconstructed ligament may be strong enough to maintain the stability of 1st CM joint and ligament reconstruction is most effective in treating post-traumatic instability

Wavefront restoration from lateral shearing data using spectral interpolation

Although a lateral-shear interferometer is robust against optical component vibrations, its interferogram provides information about differential wavefronts rather than the wavefronts themselves, resulting in the loss of specific frequency components. Previous studies have addressed this limitation by measuring four interferograms with different shear amounts to accurately restore the two-dimensional wavefront. This study proposes a technique that employs spectral interpolation to reduce the number of required interferograms. The proposed approach introduces an origin-shift technique for accurate spectral interpolation, which in turn is implemented by combining two methods: natural extension and least-squares determination of ambiguities in uniform biases. Numerical simulations confirmed that the proposed method accurately restored a two-dimensional wavefront from just two interferograms, thereby indicating its potential to address the limitations of the lateral-shear interferometer.Comment: 11 pages, 6 figure

Experimental Studies on an Embedded Structure-Soil Interaction

This paper describes the results of experimental studies performed the evaluation of the embedment effects on the dynamic characteristics of the structure and the correlation anlayses between the test results and the calculated results. The vibration tests of large scale models constructed on actual soil are carried out with the purpose of obtaining the basic data for verification study on analysis codes. In the correlation analyses, the methods used here are the sway-rocking model and the axisymmetric finite element method. These methods are confirmed to be applicable to analyse the response or the embedded structures

Mineralogy and petrology of Yamato 000593: Comparison with other Martian nakhlite meteorites

Yamato (Y) 000593 is a new nakhlite recovered from Antarctica and is composed of roughly 80% augite, 10% olivine and 10% mesostasis. Augite is chemically homogeneous except for Fe-rich rims adjacent to the mesostasis. Olivine has more extensive chemical zoning, but the most Fe-rich part is also near the mesostasis. These observations suggest that chemical zoning of both augite and olivine was produced by interaction with the mesostasis. The crystallization history of Y000593 as deduced from this study is as follows. (1) Crystallization of cumulus augite and olivine and formation of symplectites in olivine. (2) Accumulation of augite and olivine. (3) Mesostasis crystallization and interaction of the augite and olivine rims with the intercumulus melt. (4) Aqueous alteration. The petrography and mineralogy of Y000593 is generally similar to other nakhlites, but minor mineralogical differences are observed. These differences resulted from different thermal histories due to different locations (burial depths) in the same cooling cumulate pile. Y000593 is most similar to Nakhla and both samples experienced similar formation histories. However, later mesostasis crystallization of Y000593 was more rapid than Nakhla due to its faster cooling rate. The burial depth of Y000593 would be shallower than 3 m from the surface, and is intermediate between NWA817 and Nakhla. The abundance and mineralogy of the mesostasis as well as augite and olivine rim compositions are related to the burial depths of nakhlites