Interstitial water chemsitry at DSDP Leg 60 Holes

Interstitial water data obtained during Leg 60 show complex gradients at Site 453 in a sediment pond on the west side of the Mariana Trough. Concentrations of Ca, Mg, Sr, as well as of K and Li, suggest that slightly altered sea water penetrates below the sediments, most likely through brecciated igneous and metamorphic rocks, mainly gabbros, lying at the base of the pond. Interstitial water concentration gradients suggest that reactions involving igneous matter lead to increases in calcium and strontium in the pore fluids and to decreases in magnesium. Upward advection of water through the sediments does not appear to occur, so that the advected sea water most likely penetrates deeper into the breccias, perhaps leading to further hydrothermal activity elsewhere in this area. Interstitial water gradients at Sites 458 (conservative) and 459 suggest that reactions in the sediments and underlying basalts are responsible for increases in dissolved calcium and decreases in magnesium and potassium.

(Table 1) Sample description and tetrapyrrole pigment yield at DSDP Leg 60 Holes

In order to provide a better understanding of the fate of sedimentary chlorophyll and chlorophyll degradation products in all kinds of environments, we have recently expanded our studies to include examination of sediments returned from Legs which are not rich in organic matter, nor are even primarily biogenic. Eight core samples from the Mariana Basin and Trench, obtained from DSDP Leg 60, were analyzed for products of chlorophyll diagenesis. To date, the sediment samples from the South Philippine Sea have been the most organically barren examined. Through elimination of the bias of examining only sediments rich in organic matter, we hope that the fate of chlorophyllous material on a more global scale will eventually be elucidated.

Calcium carbonate global LGM Burial rate data

Global databases of calcium carbonate concentrations and mass accumulation rates in Holocene and last glacial maximum sediments were used to estimate the deep-sea sedimentary calcium carbonate burial rate during these two time intervals. Sparse calcite mass accumulation rate data were extrapolated across regions of varying calcium carbonate concentration using a gridded map of calcium carbonate concentrations and the assumption that accumulation of noncarbonate material is uncorrelated with calcite concentration within some geographical region. Mean noncarbonate accumulation rates were estimated within each of nine regions, determined by the distribution and nature of the accumulation rate data. For core-top sediments the regions of reasonable data coverage encompass 67% of the high-calcite (>75%) sediments globally, and within these regions we estimate an accumulation rate of 55.9 ± 3.6 x 10**11 mol/yr. The same regions cover 48% of glacial high-CaCO3 sediments (the smaller fraction is due to a shift of calcite deposition to the poorly sampled South Pacific) and total 44.1 ± 6.0 x 10**11 mol/yr. Projecting both estimates to 100 % coverage yields accumulation estimates of 8.3 x 10**12 mol/yr today and 9.2 x 10**12 mol/yr during glacial time. This is little better than a guess given the incomplete data coverage, but it suggests that glacial deep sea calcite burial rate was probably not considerably faster than today in spite of a presumed decrease in shallow water burial during glacial time.

Anxiety among high school students in India : comparisons across gender, school type, social strata, and perceptions of quality time with parents

The broad objective of the study was to better understand anxiety among adolescents in Kolkata city, India. Specifically, the study compared anxiety across gender, school type, socio-economic background and mothers’ employment status. The study also examined adolescents’ perceptions of quality time with their parents. A group of 460 adolescents (220 boys and 240 girls), aged 13-17 years were recruited to participate in the study via a multi-stage sampling technique. The data were collected using a self-report semi-structured questionnaire and a standardized psychological test, the State-Trait Anxiety Inventory. Results show that anxiety was prevalent in the sample with 20.1% of boys and 17.9% of girls found to be suffering from high anxiety. More boys were anxious than girls (p<0.01). Adolescents from Bengali medium schools were more anxious than adolescents from English medium schools (p<0.01). Adolescents belonging to the middle class (middle socio-economic group) suffered more anxiety than those from both high and low socio-economic groups (p<0.01). Adolescents with working mothers were found to be more anxious (p<0.01). Results also show that a substantial proportion of the adolescents perceived they did not receive quality time from fathers (32.1%) and mothers (21.3%). A large number of them also did not feel comfortable to share their personal issues with their parents (60.0% for fathers and 40.0% for mothers).

Colin Marsh (2008) Becoming a Teacher: Knowledge, Skills and Issues. 4th edition, Frenchs Forrest: Pearson Education Australia, 460 pages

Becoming a Teacher is structured in five very readable sections. The introductory section addresses the nature of teaching and the importance of developing a sense of purpose for teaching in a 21st century classroom. It also introduces some key concepts that are explored throughout the volume according to the particular chapter focus of each part. For example, the chapters in Part 2 explore aspects of student learning and the learning environment and focus on how students develop and learn, learner motivation, developing self esteem and learning environments. The concepts developed in this section, such as human development, stages of learning, motivation, and self-concept are contextualised in terms of theories of cognitive development and theories of social, emotional and moral development. The author, Colin Marsh, draws on his extensive experience as an educator to structure the narrative of chapters in this part via checklists for observation, summary tables, sample strategies for teaching at specific stages of student development, and questions under the heading ‘your turn’. Case studies such as ‘How I use Piaget in my teaching’ make that essential link between theory and practice, something which pre-service teachers struggle with in the early phases of their university course. I was pleased to see that Marsh also explores the contentious and debated aspects of these theoretical frameworks to demonstrate that pre-service teachers must engage with and critique the ways in which theories about teaching and learning are applied. Marsh weaves in key quotations and important references into each chapter’s narrative and concludes every chapter with summary comments, reflection activities, lists of important references and useful web sources. As one would expect of a book published in 2008, Becoming a Teacher is informed by the most recent reports of classroom practice, current policy initiatives and research.

Exploring health information use by older Australians within everyday life

Exploring information use within everyday or community contexts is a recent area of interest for information literacy research endeavors. Within this domain, health information literacy (HIL) has emerged as a focus of interest due to identified synergies between information use and health status. However, while HIL has been acknowledged as a core ingredient that can assist people to take responsibility for managing and improving their own health, limited research has explored how HIL is experienced in everyday community life. This article will present the findings of ongoing research undertaken using phenomenography to explore how HIL is experienced among older Australians within everyday contexts. It will also discuss how these findings may be used to inform policy formulation in health communication and as an evidence base for the design and delivery of consumer health information resources and services.

Revision total hip replacement using the cement-in-cement technique for the acetabular component : technique and results for 60 hips

The technique of femoral cement-in-cement revision is well established, but there are no previous series reporting its use on the acetabular side at the time of revision total hip arthroplasty. We describe the surgical technique and report the outcome of 60 consecutive cement-in-cement revisions of the acetabular component at a mean follow-up of 8.5 years (range 5-12 years). All had a radiologically and clinically well fixed acetabular cement mantle at the time of revision. 29 patients died. No case was lost to follow-up. The 2 most common indications for acetabular revision were recurrent dislocation (77%) and to compliment a femoral revision (20%). There were 2 cases of aseptic cup loosening (3.3%) requiring re-revision. No other hip was clinically or radiologically loose (96.7%) at latest follow-up. One case was re-revised for infection, 4 for recurrent dislocation and 1 for disarticulation of a constrained component. At 5 years, the Kaplan-Meier survival rate was 100% for aseptic loosening and 92.2% (95% CI; 84.8-99.6%) with revision for all causes as the endpoint. These results support the use of the cement-in-cement revision technique in appropriate cases on the acetabular side. Theoretical advantages include preservation of bone stock, reduced operating time, reduced risk of complications and durable fixation.

Rate of torque and electromyographic development during anticipated eccentric contraction is lower in previously strained hamstrings

Background: Hamstring strain injuries are prevalent in sport and re-injury rates have been high for many years. Whilst much focus has centred on the impact of previous hamstring strain injury on maximal eccentric strength, high rates of torque development is also of interest, given the important role of the hamstrings during the terminal swing phase of running. The impact of prior strain injury on myoelectrical activity of the hamstrings during tasks requiring high rates of torque development has received little attention. Purpose: To determine if recreational athletes with a history of unilateral hamstring strain injury, who have returned to training and competition, will exhibit lower levels of myoelectrical activity during eccentric contraction, rate of torque development and impulse 30, 50 and 100ms after the onset of myoelectrical activity or torque development in the previously injured limb compared to the uninjured limb. Study design: Case-control study Methods: Twenty-six recreational athletes were recruited. Of these, 13 athletes had a history of unilateral hamstring strain injury (all confined to biceps femoris long head) and 13 had no history of hamstring strain injury. Following familiarisation, all athletes undertook isokinetic dynamometry testing and surface electromyography assessment of the biceps femoris long head and medial hamstrings during eccentric contractions at -60 and -1800.s-1. Results: In the injured limb of the injured group, compared to the contralateral uninjured limb rate of torque development and impulse was lower during -600.s-1 eccentric contractions at 50 (RTD, injured limb = 312.27 ± 191.78Nm.s-1 vs. uninjured limb = 518.54 ± 172.81Nm.s-1, p=0.008; IMP, injured limb = 0.73 ± 0.30 Nm.s vs. uninjured limb = 0.97 ± 0.23 Nm.s, p=0.005) and 100ms (RTD, injured limb = 280.03 ± 131.42Nm.s-1 vs. uninjured limb = 460.54.54 ± 152.94Nm.s-1,p=0.001; IMP, injured limb = 2.15 ± 0.89 Nm.s vs. uninjured limb = 3.07 ± 0.63 Nm.s, p<0.001) after the onset of contraction. Biceps femoris long head muscle activation was lower at 100ms at both contraction speeds (-600.s-1, normalised iEMG activity (x1000), injured limb = 26.25 ± 10.11 vs. uninjured limb 33.57 ± 8.29, p=0.009; -1800.s-1, normalised iEMG activity (x1000), injured limb = 31.16 ± 10.01 vs. uninjured limb 39.64 ± 8.36, p=0.009). Medial hamstring activation did not differ between limbs in the injured group. Comparisons in the uninjured group showed no significant between limbs difference for any variables. Conclusion: Previously injured hamstrings displayed lower rate of torque development and impulse during slow maximal eccentric contraction compared to the contralateral uninjured limb. Lower myoelectrical activity was confined to the biceps femoris long head. Regardless of whether these deficits are the cause of or the result of injury, these findings could have important implications for hamstring strain injury and re-injury. Particularly, given the importance of high levels of muscle activity to bring about specific muscular adaptations, lower levels of myoelectrical activity may limit the adaptive response to rehabilitation interventions and suggest greater attention be given to neural function of the knee flexors following hamstring strain injury.