Distribution in SAR palaeodoses due to spatial heterogeniety of natural beta dose

In luminescence dating of sediments, Mayya et al. (2006) pointed out that at single grain level, the beta dose for quartz grains is heterogeneous. This heterogeneity arises due the fact that the total potassium in sediment is contributed by few feldspar grains with up to 11–14% stoichiometric potassium (Huntley and Baril, 1997). Beta particles have a range of ∼2 mm, which is comparable to grain sizes and inter-grain distances. This fact implies that the spatial fluctuation of beta emitters (K-feldspars) around individual quartz grains results in heterogeneous dose deposition. These fluctuations therefore, lead to an inherent spread in palaeodoses received by individual quartz grains.     

Socio-Economic Factors Affecting Marriage Distance in Two Sikh Villages of Punjab

The spatial aspects of marriage in two Sikh villages in the Indian state of Punjab are investigated with the findings compared to earlier sudies in other parts of India. One village had experienced the Green Revolution, hut the second had not. A radius of roughly 25 miles demarcates the limit of over 80% of marriage interaction in both villages, and a “crater effect” was observed in the distance decay of marriages. An expansion of the marriage field had taken place in the village influenced by Green Revolution changes, whereas no similar change occurred in the village practicing traditional agriculture. Both the extent of the marriage field and the variations in the intensity of marriage links within the field were affected by socio-economic factors including level of education, caste and extent of land ownership.     

Anomalous fading and crystalline structure: Studies on individual chondrules from the same parent body

Plagioclase feldspar is the major luminescent mineral in meteorites. Thermoluminescence (TL) characteristics, peak temperature (T_m), full width at half maximum (FWHM), ratio of high (HT) to low temperature (LT) peak, and TL sensitivity (TL/dose/mass) to an extent reflect degree of crystallinity of the mineral. The present study explores and establishes a correlation between quantum mechanical anomalous (athermal) fading and structural state by examining TL of individual chondrules. Chondrules were separated using freeze-thaw technique from a single fragment of Dhajala meteorite. The results show large variation in T_m (155?230°C), FWHM (80?210°C) and HT/LT (0.07–0.47) and seem to be positively correlated. TL sensitivity (ranging from 14 to 554 counts/s/Gy/mg) decreases with increasing T_m and FWHM. Large variations in TL parameters (Tm, FWHM, HT/LT, and Sensitivty) suggest that individual chondrules had different degree of crystallization. Thermal annealing experiments suggest that comparatively ordered form of feldspar can be converted to a disordered form by annealing the sample at high temperatures (1000°C) for long time (10 hr) in vacuum (1 mbar pressure) condition and rapidly cooling it. Measured anomalous fading suggest that fading rate increases as the crystal form changes from an ordered state to a disordered state. However, the fading rate becomes nearly negligible for the most disordered feldspars.     

Aspects of Infrared Radioluminescence dosimetry in K-feldspar

Infrared radioluminescence (IRRL) of K-feldspar, detected at peak wavelength of 865 nm, is emerging as a potential geochronometric tool. The present study explores and attempts to optimize the IRRL dating protocols and proposes a revised protocol for estimation of palaeodose. UV light (395 nm; 700 mW/cm2) bleach of 800 s was optimum to remove the trapped charges responsible for IRRL and, reduced the interference of radio-phosphorescence due to prior irradiations. Validation of the proposed protocol was carried out by dose recovery tests on mineral and sediment K-feldspar samples of different provenances. An overestimation in dose recovery was observed and was attributed to difference in sensitivity of natural IRRL and regenerated IRRL. The sensitivity changes were significant and systematic and were documented by repeating bleach-IRRL cycles. Corrections for sensitivity changes between natural and regenerated IRRL, gave reliable results and, have now been included in the proposed dating protocol.     

Rapid denudation of Higher Himalaya during late Pliestocence, evidence from OSL thermochronology

Optically Stimulated Luminescence (OSL) of quartz, with closure temperatures of 30–35°C in conjunction with Apatite Fission Track (AFT; closure temp. ～120°C) and ⁴⁰Ar-³⁹Ar (biotite closure temperature ～350°C), were used to obtain cooling ages from Higher Himalayan crystalline rocks of Western Arunachal Himalaya (WAH). Cooling age data based on OSL, AFT and Ar-Ar thermochronology provide inference on the exhumation — erosion history for three different time intervals over million to thousand year scale. Steady-state exhumation of ～0.5 mm/yr was observed during Miocene (>7.2 Ma) till Early Pleistocene (1.8 Ma). Onset of Pleistocene glacial/interglacial conditions from ～1.8 Ma formed glaciated valleys and rapid erosion with rivers incising deep valleys along their course. Erosion enables midcrustal partial melts to move beneath the weak zone in the valley and causes an erosion-induced tectonic uplift. This resulted in a rapid increase in exhumation rate. The OSL thermochronology results suggest increased erosion over ～21 ka period from Late Pleistocene (2.5 mm/yr) to Early Holocene (5.5 mm/yr) and these are to be contrasted with pre 1.8 Ma erosion rate of 0.5 mm/yr. Enhanced erosion in the later stage coincides with the periods of deglaciation during Marine Isotope Stages (MIS) 1 and 2. The results of the present study suggest that in the present setting OSL thermochronology informed on the short-term climatic effect on landscape evolution and techniques like the AFT and ⁴⁰Ar-³⁹Ar provided longer-term exhumation histories.     

Neural Network-Based Damage Detection from Transfer Function Changes

This article puts forth the work on a neural network-based approach to determine the degree of damaged floors of the building considering changes in the transfer function. The transfer function is considered for that part of forced vibration in which system vibrates linearly after the structure has been damaged considering the building is instrumented during the earthquake. The results showed that accuracy of degree of damage detected increased with the increase in the number of combination of damages. The instrumentation of the first floor is expected to give best results for damage detection based on the transfer function-based approach.     

Lead concentrations in bones and soil

Lead concentrations were measured in 41 rib samples from the Romano-British cemetery at Poundbury and in two sets of soil samples from the graves yielding up the bones. The levels of lead in the soil were in no way exceptional (means for the two series were 16·7 and 24·8 μg/g dry weight) and there was no correlation between soil lead and bone lead concentrations.Since bone lead concentrations vary independently of those in the soil, it is unlikely that the bones are contaminated by lead in the soil, at least under the conditions prevailing at this particular site.