3,219 research outputs found
Temporal distribution and frequency of explosive volcanism in the Kermadec Arc, SW Pacific: Insights from marine cores
Studies along the Kermadec arc, SW Pacific, over the past two decades have shown the presence of numerous volcanoes with histories of caldera collapse, and abundant evidence of explosive eruptions involving evolved magmas (dacite to rhyodacite). However, as there are only two substantially emergent volcanoes in the arc, Raoul and Macauley, the history of this explosive volcanism is difficult to constrain from subaerial exposures. In contrast, the marine record offers the opportunity to document activity from these volcanoes over a longer time period. This thesis presents stratigraphic and chemical data from sediment cores collected along offshore transects west and east of Raoul and Macauley islands. Individual grain analysis of glass shards from the tephra layers was conducted using electron microprobe and laser ablation inductively coupled plasma mass spectrometry to analyse each shard for major and trace element compositions. These geochemical data allowed for discrimination between successive tephra deposits, and identification of 51 tephra layers in the cores, each of which is interpreted to represent a single eruptive event. The data also addressed the diversity or uniformity of individual eruptions and traced changes in the geochemistry of the eruption units through time. Oxygen isotope analyses of foraminifera were used to construct an age model for the cores, allowing model age estimates of individual tephra units and proving the marine core record extends back to ca. 170 ka. Silicic volcanism from these two volcanoes dates back to at least ca. 166 ka, indicating that it is not a recent development as the onshore record would suggest. Onshore exposures on Macauley Island record only one silicic eruption, the 6.3 ka Sandy Bay Tephra; however, the offshore cores show that Macauley has erupted silicic magmas since 166 ka, and is the dominant source for tephras recorded in the cores.
Construction of a tephrochronology of the cores provides a context as to the eruptive frequency of volcanoes along the arc, indicates apparent fluctuations in the magma supply rate, and also indicates that fractionation is the dominant process by which silicic magmas are generated in the arc. The average eruptive frequency of Raoul and Macauley volcanoes is 1 eruption/kyr. If extrapolated to the other volcanoes along the arc, there are ca. 40 eruptions/kyr of significant size that could be preserved in the marine record. The presence of periods of quiescence in the eruptive history implies that magma supply rates may have a primary control on the frequency of eruptions linked to compositions, such that when supply rates slow, the magmas stall in the crust and fractionate to form silicic magmas
An In-Depth Look at 4-H Enrollment and Retention
The membership of 4-H is a highly fluctuating, variable body, with youth coming and going at all ages. A more complete understanding of this fluctuation can be obtained by examining enrollment and retention trends, allowing agents to identify key strategies to increase membership in their own counties. By using the ES 237 data for Colorado from 2002 and 2003, it was possible to recognize patterns that have implications for the ways agents handle recruitment. Increasing retention in 4-H is most closely linked to enrolling youth at an early age and preventing the loss of first year members
History: The San and Its Mission
This book is a re-telling of the story of the mission of the Sydney Adventist Hospital - even today still known fondly to many as the San - based on the many stories and vignettes shared by people, and about people, who lived the San\u27s mission, contributing to a hospital that has had an impact on many lives.This is not a chronological and systematic historical narrative, but it uses the motivation and inspiration of individuals and events to illustrate how the mission of the hospital has been fulfilled through its healing and restorative ministry since 1903. It also illustrates how mission inspired individuals, decisions, strategies and the pioneering work that remains the hallmark of the San
Bedside Calculation of Energy Expenditure Does Not Guarantee Adequate Caloric Prescription in Long-Term Mechanically Ventilated Critically Ill Patients: A Quality Control Study
Nutrition is essential in critically ill patients, but translating caloric prescriptions into adequate caloric intake remains challenging. Caloric prescriptions (P), effective intake (I), and caloric needs (N), calculated with modified Harris-Benedict formulas, were recorded during seven consecutive days in ventilated patients. Adequacy of prescription was estimated by P/N ratio. I/P ratio assessed accuracy of translating a prescription into administered feeding. I/N ratio compared delivered calories with theoretical caloric needs. Fifty patients were prospectively studied in a mixed medicosurgical ICU in a teaching hospital. Basal and total energy expenditure were, respectively, 1361 ± 171 kcal/d and 1649 ± 233 kcal/d. P and I attained 1536 ± 602 kcal/d and 1424 ± 572 kcal/d, respectively. 24.6% prescriptions were accurate, and 24.3% calories were correctly administered. Excessive calories were prescribed in 35.4% of patients, 27.4% being overfed. Caloric needs were underestimated in 40% prescriptions, with 48.3% patients underfed. Calculating caloric requirements by a modified standard formula covered energy needs in only 25% of long-term mechanically ventilated patients, leaving many over- or underfed. Nutritional imbalance mainly resulted from incorrect prescription. Failure of “simple” calculations to direct caloric prescription in these patients suggests systematic use of more reliable methods, for example, indirect calorimetry
A pilot study of hair and cytokine balance alteration in healthy young women under major exam stress
Mouse models show that experimental stress mimicking prolonged life-stress
exposure enhances neurogenic inflammation, induces adaptive immunity cytokine-
imbalance characterized by a shift to Type 1 T-helper cell cytokines and
increases apoptosis of epithelial cells. This affects hair growth in otherwise
healthy animals. In this study, we investigate whether a prolonged
naturalistic life-stress exposure affects cytokine balance and hair parameters
in healthy humans. 33 (18 exam, 15 comparison) female medical students with
comparable sociobiological status were analyzed during a stressful final
examination period, at three points in time (T) 12 weeks apart. T1 was before
start of the learning period, T2 between the three-day written exam and an
oral examination, and T3 after a 12 week rest and recovery from the stress of
the examination period. Assessments included: self-reported distress and
coping strategies (Perceived Stress Questionnaire [PSQ], Trier Inventory for
the Assessment of Chronic Stress [TICS]), COPE), cytokines in supernatants of
stimulated peripheral blood mononucleocytes (PBMCs), and trichogram (hair
cycle and pigmentation analysis). Comparison between students participating in
the final medical exam at T2 and non-exam students, revealed significantly
higher stress perception in exam students. Time-wise comparison revealed that
stress level, TH1/TH2 cytokine balance and hair parameters changed
significantly from T1 to T2 in the exam group, but not the control. However,
no group differences were found for cytokine balance or hair parameters at T2.
The study concludes that in humans, naturalistic stress, as perceived during
participation in a major medical exam, has the potential to shift the immune
response to TH1 and transiently hamper hair growth, but these changes stay
within a physiological range. Findings are instructive for patients suffering
from hair loss in times of high stress. Replication in larger and more diverse
sample populations is required, to assess suitability of trichogram analysis
as biological outcome for stress studies
Does acute passive stretching increase muscle length in children with cerebral palsy?
This article has been made available through the Brunel Open Access Publishing Fund. Copyright @ The Authors. This article is distributed under the terms of the Creative Commons Attribution
Noncommercial License which permits any noncommercial use, distribution, and
reproduction in anymedium, provided the original author(s) and the source are credited.Background: Children with spastic cerebral palsy experience increased muscle stiffness and reduced muscle length, which may prevent elongation of the muscle during stretch. Stretching performed either by the clinician, or children themselves is used as a treatment modality to increase/maintain joint range of motion. It is not clear whether the associated increases in muscle–tendon unit length are due to increases in muscle or tendon length. The purpose was to determine whether alterations in ankle range of motion in response to acute stretching were accompanied by increases in muscle length, and whether any effects would be dependent upon stretch technique. Methods: Eight children (6–14 y) with cerebral palsy received a passive dorsiflexion stretch for 5 × 20 s to each leg, which was applied by a physiotherapist or the children themselves. Maximum dorsiflexion angle, medial gastrocnemius muscle and fascicle lengths, and Achilles tendon length were calculated at a reference angle of 10° plantarflexion, and at maximum dorsiflexion in the pre- and post-stretch trials. Findings: All variables were significantly greater during pre- and post-stretch trials compared to the resting angle, and were independent of stretch technique. There was an approximate 10° increase in maximum dorsiflexion post-stretch, and this was accounted for by elongation of both muscle (0.8 cm) and tendon (1.0 cm). Muscle fascicle length increased significantly (0.6 cm) from pre- to post-stretch. Interpretation: The results provide evidence that commonly used stretching techniques can increase overall muscle, and fascicle lengths immediately post-stretch in children with cerebral palsy
Halogenation for improvement of seed yield and quality in chilli (Capsicum annuum L.)
Freshly harvested seeds of chilli variety Anugraha were treated with halogens namely Calcium oxy chloride (CaOCl2) and Iodine crystal (I2) indirectly through a carrier Calcium carbonate (CaCO3). The treatments included Control (Untreated), CaOCl2 + CaCO3 (2g each/kg seed), CaOCl2 + CaCO3 (4g each/kg seed), Iodine crystal + CaCO3 (50mg each/kg seed) and Iodine crystal + CaCO3 (100mg each/kg seed). Seed treatment with CaOCl2 + CaCO3 @2g each/kg seed registered significantly higher values for fruits per plant, fruit weight, seed yield per plant and hundred seed weight followed by CaOCl2 + CaCO3 @4g each/kg seed. The treatments, CaOCl2 + CaCO3 @2 g each/kg seed and Iodine crystal + CaCO3 @100mg each/kg seed performed superior in seed quality with higher seedling vigour and lower electrical conductivity of seed leachates over other treatments, while untreated control recorded least seedling vigour indices and highest electrical conductivity
Effect of seed invigoration with inorganic nanoparticles on seed yield in chilli (Capsicum annum)
An experiment was conducted to study the effect of seed invigoration with inorganic nanoparticles on plant growth and seed yield of chilli. Seed invigoration with nano particles of ZnO and TiO2 was found to be beneficial in improving yield and yield attributes. Seed treatment with nano ZnO @ 1300 mg kg-1 of seed and nano TiO2 @ 900 mg kg-1 exhibited increased plant height, fruits per plant, fruit length, fruit yield, number of seeds per fruit and seed yield
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