New constraints from zircon, monazite and uraninite dating on the commencement of sedimentation in the Cuddapah basin, India

2017 ◽  
Vol 155 (6) ◽  
pp. 1230-1246 ◽  
Author(s):  
DEBIDARSANI SAHOO ◽  
KAMAL LOCHAN PRUSETH ◽  
DEWASHISH UPADHYAY ◽  
SAMEER RANJAN ◽  
DIPAK C. PAL ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Hydrothermal Activity ◽  
Time Span ◽  
Detrital Zircons ◽  
Cuddapah Basin ◽  
Relative Timing ◽  
Considerable Time ◽  
Long Span ◽  
Considerable Confusion ◽  
Age Constraints

AbstractThe Cuddapah basin in southern India, consisting of the Palnad, Srisailam, Kurnool and Papaghni sub-basins, contains unmetamorphosed and undeformed sediments deposited during a long span of time in the Proterozoic. In the absence of robust age constraints, there is considerable confusion regarding the relative timing of sedimentation in these sub-basins. In this study, U–Pb isotopic dating of zircon and U–Th–Pbtotaldating of monazite and uraninite from the gritty quartzite that supposedly belongs to the formation Banganapalle Quartzite have been used to constrain the beginning of sedimentation in the Palnad sub-basin. Magmatic and detrital zircons recording an age of 2.53 Ga indicate that the sediments were derived from the granitic basement or similar sources and were deposited after 2.53 Ga. Hydrothermally altered zircons both in the basement and the cover provide concordant ages of 2.32 and 2.12 Ga and date two major hydrothermal events. Thus, the gritty quartzite must have been deposited sometime between 2.53 and 2.12 Ga and represents the earliest sediments in the Cuddapah basin. Monazite and uraninite give a wide spectrum of ages between 2.5 Ga and 150 Ma, which indicates several pulses of hydrothermal activity over a considerable time span, both in the basement granite and the overlying quartzite. The new age constraints suggest that the gritty quartzite may be stratigraphically equivalent to the Gulcheru Quartzite that is the oldest unit in the Cuddapah basin, and that a sedimentary/erosional hiatus exists above it.

Perception of Terminal Fall Contours in Speech Produced by Deaf Persons

1990 ◽  
Vol 33 (1) ◽  
pp. 174-180 ◽  
Author(s):  
Judith Rubin-Spitz ◽  
Nancy S. McGarr
Keyword(s):  
Regression Analysis ◽  
Significant Contribution ◽  
Linear Regression Analysis ◽  
Regression Function ◽  
Multiple Linear Regression Analysis ◽  
Deaf Children ◽  
Relative Timing ◽  
Acoustic Measures ◽  
Final Syllable ◽  
Deaf Persons

Eight deaf children produced each of nine sentences. F 0 measures were obtained at several locations within each utterance (starting F 0 , peak F 0 , peak F 0 in the final syllable, and final F 0 ). The relative timing of each F 0 measure (ms from onset of the utterance) was also determined. In addition, several difference measures were derived. Listeners experienced with the speech of the deaf were asked to judge whether they heard a terminal fall, rise, or a flat final intonation contour in each utterance. A multiple linear regression analysis was used to determine if any combination of the acoustic measures could predict listeners’ responses. The only variable that made a significant contribution to the regression function was the temporal interval between the terminal peak F 0 and the final F 0 . That is, the more slowly the contour fell the more likely listeners were to perceive the contour as flat, regardless of the amount (in Hz or percentage F 0 ) by which it fell. The regression equation accounted for a statistically significant but not large proportion of the total variance. This suggests that other variables, not measured in this study, play an important role in the perception of utterance final intonation contours in the speech of the deaf.

New highlights of gamma-ray observations by ASIM

2021 ◽  
Author(s):  
Nikolai Ostgaard ◽  
Andrey Mezentsev ◽  
Martino Marisaldi ◽  
Pavlo Kochkin ◽  
Torsten Neubert ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Optical Measurements ◽  
High Flux ◽  
Relative Timing ◽  
Optical Pulses ◽  
Timing Accuracy ◽  
New Science ◽  
Radio Measurements

<p><span>ASIM has now observed several hundreds of TGFs since the launch in 2018. Highlights and new science from the first ten months of observations were presented in Østgaard et al. (2019) paper. In this presentation we will present observational highlights from the last 1.5 year, when the relative timing accuracy between the TGF observations and the optical measurements is +/- 5 us (compared to +/- 80 us before march 2019). This includes many more simultaneous TGF and Elve observations, high flux TGFs, double TGFs simultaneous with double optical pulses and many TGFs with good radio measurements.<span>  </span>ASIM has also observed several Gamma Ray Bursts.<span> </span></span></p>

scholarly journals The relative timing of Lunar Magma Ocean solidification and the Late Heavy Bombardment inferred from highly degraded impact basin structures

Icarus ◽  
2015 ◽  
Vol 250 ◽  
pp. 492-503 ◽  
Author(s):  
Shunichi Kamata ◽  
Seiji Sugita ◽  
Yutaka Abe ◽  
Yoshiaki Ishihara ◽  
Yuji Harada ◽  
...  
Keyword(s):  
Relative Timing ◽  
Magma Ocean ◽  
Late Heavy Bombardment

Wipe and flexion reflexes of the frog. II. Response to perturbations

1993 ◽  
Vol 69 (5) ◽  
pp. 1736-1748 ◽  
Author(s):  
J. L. Schotland ◽  
W. Z. Rymer
Keyword(s):  
External Load ◽  
Hind Limb ◽  
Joint Angle ◽  
Activity Level ◽  
Temporal Organization ◽  
Emg Activity ◽  
Relative Timing ◽  
Before And After ◽  
Movement Segment ◽  
Initial Movement

1. To evaluate the hypothesis that the neural control of sensorimotor transformations may be simplified by using a single control variable, we compared the movement kinematics and muscle activity patterns [electromyograms (EMGs)] of the frog during flexion withdrawal and the hind limb-hind limb wipe reflex before and after adding an external load. In addition, the flexibility of spinal cord circuitry underlying the hind limb-hind limb wipe reflex was evaluated by comparing wipes before and after removal of one of the contributing muscles by cutting a muscle nerve. 2. The kinematics of the movements were recorded using a WATSMART infrared emitter-detector system and quantified using principal-components analysis to provide a measure of the shape (eigenvalues) and orientation (eigenvector coefficients) of the movement trajectories. The neural pattern coordinating the movements was characterized by the latencies and magnitudes of EMGs of seven muscles acting at the hip, knee, and ankle. These variables were compared 1) during flexion withdrawal and the initial movement segment of the limb during the hind limb-hind limb wipe reflex in both unrestrained movements and in movements executed when a load equal to approximately 10% of the animal's body weight was attached to a distal limb segment and 2) during the initial movement segment of the wipe reflex before and after cutting the nerve to the knee flexor-hip extensor, iliofibularis. 3. Addition of the load had no discernible effect on the end-point position of the foot during either reflex. However, during the loaded flexion reflex, the ankle joint did not move until after the hip and knee joints had moved to their normal positions. This delayed flexion of the ankle was accompanied by large increases in the magnitude of EMG activity in two ankle muscles that exceeded the levels found during unrestrained movements. Significant changes in the temporal organization of the EMG pattern accompanied the change in joint angle relations during flexion withdrawal. 4. Despite the addition of an external load, all animals successfully and reliably removed the stimulus during the wipe reflex, and the relative timing of both the EMG pattern and joint angle motion was preserved. 5. Immediately after section of the nerve to a single muscle (iliofibularis), all animals successfully and reliably removed the stimulus during the wipe reflex. The relative timing of muscle activation was preserved, accompanied by a reduction in the activity level of gluteus magnus, a muscle with action reciprocal to iliofibularis.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals The last deglaciation of Peru and Bolivia

2017 ◽  
Vol 43 (2) ◽  
pp. 591 ◽  
Author(s):  
B. Mark ◽  
N. Stansell ◽  
G. Zeballos
Keyword(s):  
General Pattern ◽  
Late Glacial ◽  
Relative Timing ◽  
Last Deglaciation ◽  
Tropical Andes ◽  
Mountain Ranges ◽  
Tropical Glaciers ◽  
Sedimentary Records ◽  
The Last Deglaciation ◽  
The Antarctic

The tropical Andes of Peru and Bolivia are important for preserving geomorphic evidence of multiple glaciations, allowing for refinements of chronology to aid in understanding climate dynamics at a key location between hemispheres. This review focuses on the deglaciation from Late-Pleistocene maximum positions near the global Last Glacial Maximum (LGM). We synthesize the results of the most recent published glacial geologic studies from 12 mountain ranges or regions within Peru and Bolivia where glacial moraines and drift are dated with terrestrial cosmogenic nuclides (TCN), as well as maximum and minimum limiting ages based on radiocarbon in proximal sediments. Special consideration is given to document paleoglacier valley localities with topographic information given the strong vertical mass balance sensitivity of tropical glaciers. Specific valley localities show variable and heterogeneous sequences ages and extensions of paleoglaciers, but conform to a generally cogent regional sequence revealed by more continuous lake sedimentary records. There are clear distributions of stratigraphically older and younger moraine ages that we group and discuss chronologically. The timing of the local LGM based on average TCN ages of moraine groups is 25.1 ka, but there are large uncertainties (up to 7 ka) making the relative timing with the global LGM elusive. There are a significant number of post-LGM moraines that date to 18.9 (± 0.5) ka. During the Oldest Dryas (18.0 to 14.6 ka), moraine boulders date to 16.1 (± 1.1) ka, suggesting that glaciers either experienced stillstands or readvances during this interval. The Antarctic Cold Reversal (ACR; 14.6 to 12.6 ka) is another phase of stillstanding or readvancing glaciers with moraine groups dating to 13.7 (± 0.8) ka, followed by retreating ice margins through most of the Younger Dryas (YD; 12.9 to 11.8 ka). During the early Holocene, groups of moraines in multiple valleys date to 11.0 (± 0.4) ka, marking a period when glaciers either readvanced or paused from the overall trend of deglaciation. The pattern of glacial variability during the Late Glacial after ~14.6 ka appears to be more synchronous with periods of cooling in the southern high latitudes, and out-of-phase with the overall deglacial trend in the Northern Hemisphere. While insolation and CO2 forcing likely drove the general pattern of deglaciation in the southern tropical Andes, regional ocean-atmospheric and hypsometric controls must have contributed to the full pattern of glacial variability.

Sign in / Sign up

Export Citation Format

Share Document