Mid-crustal deformation of the Annapurna-Dhaulagiri Himalaya, central Nepal: An atypical example of channel flow during the Himalayan orogeny

The channel-flow model for the Greater Himalayan Sequence (GHS) of the Himalayan orogen involves a partially molten, rheologically weak, mid-crustal layer “flowing” southward relative to the upper and lower crust during late Oligocene–Miocene. Flow was driven by topographic overburden, underthrusting, and focused erosion. We present new structural and thermobarometric analyses from the GHS in the Annapurna-Dhaulagiri Hima­laya, central Nepal; these data suggest that during exhumation, the GHS cooled, strengthened, and transformed from a weak “active channel” to a strong “channel plug” at greater depths than elsewhere in the Himalaya. After strengthening, continued convergence resulted in localized top-southwest (top-SW) shortening on the South Tibetan detachment system (STDS). The GHS in the Annapurna-Dhaulagiri Himalaya displays several geological features that distinguish it from other Himalayan regions. These include reduced volumes of leucogranite and migmatite, no evidence for partial melting within the sillimanite stability field, reduced structural thickness, and late-stage top-southwest shortening in the STDS. New and previously published structural and thermobarometric constraints suggest that the channel-flow model can be applied to mid-Eocene–early Miocene mid-crustal evolution of the GHS in the Annapurna-Dhaulagiri Himalaya. However, pressure-temperature-time (PTt) constraints indicate that following peak conditions, the GHS in this region did not undergo rapid isothermal exhumation and widespread sillima­nite-grade decompression melting, as commonly recorded elsewhere in the Hima­laya. Instead, lower-than-typical structural thickness and melt volumes suggest that the upper part of the GHS (Upper Greater Himalayan Sequence [UGHS]—the proposed channel) had a greater viscosity than in other Hima­layan regions. We suggest that viscosity-limited, subdued channel flow prevented exhumation on an isothermal trajectory and forced the UGHS to exhume slowly. These findings are distinct from other regions in the Himalaya. As such, we describe the mid-crustal evolution of the GHS in the Annapurna-­Dhaulagiri Himalaya as an atypical example of channel flow during the Himalayan orogeny

Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy

We review HB stars in a broad astrophysical context, including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy is presented, which provides unprecedented detail regarding its origin and systematics. We show that the Oosterhoff dichotomy and the distribution of globular clusters (GCs) in the HB morphology-metallicity plane both exclude, with high statistical significance, the possibility that the Galactic halo may have formed from the accretion of dwarf galaxies resembling present-day Milky Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the second-parameter problem is presented. A technique is proposed to estimate the HB types of extragalactic GCs on the basis of integrated far-UV photometry. The relationship between the absolute V magnitude of the HB at the RR Lyrae level and metallicity, as obtained on the basis of trigonometric parallax measurements for the star RR Lyrae, is also revisited, giving a distance modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are studied. Finally, the conductive opacities used in evolutionary calculations of low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and Space Scienc

Cation activation of pyrophosphatases from soil microorganisms

The intracellular inorganic pyrophosphatases obtained from mixed cultures of soil microorganisms were characterised in terms of the activating cation and pH-activity profile. Microorganisms were grown in an initial culture 10 mm in tetrasodium pyrophosphate, a nutritionally non-specific aqueous medium, buffered at pH 7.0 with an organic buffer and inoculated with soil. The intracellular pyrophosphatases in a desalted, cell-free enzyme preparation were examined for activity in assays using 1 mM tetrasodium pyrophosphate and nine cations (Mg, Zn, Co, Mn, Fe, Ca, Cu, Al and Fe) over the pH range 2-10, with appropriate buffers. Only the first 5 cations activated the enzymes. The pH-activity profiles for each cation were different and each displayed only one pH optimum. The pH optima were not greatly affected by cation concentration or kind of buffer. The specific activities at the optimum pH and cation concentration for each culture decreased in order Mg > Zn > Co > Mn > Fe. The results indicate the production of functionally similar enzymes by diverse microorganisms

Histologic grading of primary prostatic carcinoma--study of Gleason histologic grading

1973年1月から13年間に, 経験した未治療の前立腺癌98症例について, 取扱い規約およびGleasonの分類に基づいて組織学的に分類し, 予後との関係について検討した.1) Gleason分類のscoreは取扱い規約の分類とよい相関を示した.2) Gleason分類のscoreは臨床病期が進むにつれて高くなる傾向を示したが, stage Aでscoreが10の症例が1例認められ, stage Dでscoreが3の症例を認めた.3) Gleason分類のscoreが低い症例の生存率は最もよかったが, 各scoreの群間では必ずしも生存率に有意差を認めなかったGleason histologic grading for prostatic carcinoma was evaluated in a retrospective analysis. The present study comprises 98 cases of prostatic adenocarcinoma followed from January, 1973 to December, 1985. Histological materials were obtained by needle biopsy, transurethral resection or by suprapubic prostatectomy. Such slides were examined by a pathologist without previous knowledge of the patients and were assigned according to the General Rules for Clinical and Pathological Studies on Prostatic Cancer (1985) or Gleason system. Most patients fell within a Gleason score of 6, 7 and 8, and had a correspondingly high stage tumors. The survival rate for the patients was analyzed according to Gleason score. Because of the small numbers of patients some scores were combined. There were no cancer deaths for the 15 patient with a Gleason score under 5. Patients with a higher score (9-10) had a poorer prognosis (32% of survival rate at 2, 234 days), but there was no significant correlation between a Gleason score of 6, 7 or 8, or that of a higher score (9-10) and survival rate