Greatest Changes (greatest + change)

Distribution by Scientific Domains


Selected Abstracts


The relation of personality types to physiological, behavioural, and cognitive processes

EUROPEAN JOURNAL OF PERSONALITY, Issue 5 2005
Daniel Hart
Three personality types, labeled resilient, over-controlled, and under-controlled, were identified through cluster analysis of classroom observations of 63 children, and used to understand biological, cognitive, and behavioural processes that influence academic achievement and aggression. Resilient children were found to be high in trait cortisol and high in academic achievement. Under-controlled and over-controlled children showed the greatest change in cortisol levels under stress, low levels of academic achievement, and attributed hostility to others in ambiguous situations. Under-controlled children also exhibited high levels of externalizing behaviour in the classroom. The findings suggest that the single processes or traits assessed in this study do not mediate the associations of personality types to academic achievement and behaviour. The implications of the findings for the personality type construct and for personality processes are discussed. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Seasonal variation in ,13C and ,18O of cellulose from growth rings of Pinus radiata

PLANT CELL & ENVIRONMENT, Issue 11 2002
M. M. Barbour
Abstract Seasonal variation in ,13C and ,18O of cellulose (,13Cc and ,18Oc) was measured within two annual rings of Pinus radiata growing at three sites in New Zealand. In general, both ,13Cc and ,18Oc increased to a peak over summer. The three sites differed markedly in annual water balance, and these differences were reflected in ,13Cc and ,18Oc. Average ,13Cc and ,18Oc from each site were positively related, so that the driest site had the most enriched cellulose. ,13Cc and ,18Oc were also related within each site, although both the slope and the closeness of fit of the relationship varied between sites. Supporting the theory, the site with the lowest average relative humidity also had the greatest change in ,18Oc, change in ,13Cc. Specific climatic events, such as drought or high rainfall, were recorded as a peak or a trough in enrichment, respectively. These results suggest that seasonal and between-site variation in ,13Cc and ,18Oc are driven by the interaction between variation in climatic conditions and soil water availability, and plant response to this variation. [source]


Influence of initial mixing methods on melt-extruded single-walled carbon nanotube,polypropylene nanocomposites

POLYMER ENGINEERING & SCIENCE, Issue 9 2010
Vinod K. Radhakrishnan
We report the first direct comparison of melt-extruded polypropylene,single-walled carbon nanotube (PP/SWNT) nanocomposites prepared by three different initial mixing methods. The standard deviation of the G-band intensity obtained using Raman mapping was found to be the best measure of dispersion uniformity in the extruded composites, and dispersion uniformity was found to generally correlate with rheological and thermal properties. For all three initial mixing methods, both unmodified and sidewall-functionalized purified SWNTs were evaluated. Surprisingly, in all cases, dodecylated SWNTs prepared using the reductive alkylation method were less uniformly dispersed in the final composite than the unmodified SWNTs. The simplest process, dry blending, resulted in poor nanotube dispersion and only polymer crystallization was significantly affected by the presence of the nanotubes. A slightly more complex rotary evaporation process resulted in significantly more uniform dispersion and significant changes in rheological properties, polymer crystallization, and thermal stability. The most elaborate process tested, hot coagulation, enabled the most uniform dispersion and the greatest change in properties but also resulted in some polymer degradation. POLYM. ENG. SCI., 50:1831,1842, 2010. © 2010 Society of Plastics Engineers [source]


Impact of freezing on pH of buffered solutions and consequences for monoclonal antibody aggregation

BIOTECHNOLOGY PROGRESS, Issue 3 2010
Parag Kolhe
Abstract Freezing of biologic drug substance at large scale is an important unit operation that enables manufacturing flexibility and increased use-period for the material. Stability of the biologic in frozen solutions is associated with a number of issues including potentially destabilizing pH changes. The pH changes arise from temperature-associated change in the pKas, solubility limitations, eutectic crystallization, and cryoconcentration. The pH changes for most of the common protein formulation buffers in the frozen state have not been systematically measured. Sodium phosphate buffer, a well-studied system, shows the greatest change in pH when going from +25 to ,30°C. Among the other buffers, histidine hydrochloride, sodium acetate, histidine acetate, citrate, and succinate, less than 1 pH unit change (increase) was observed over the temperature range from +25 to ,30°C, whereas Tris-hydrochloride had an ,1.2 pH unit increase. In general, a steady increase in pH was observed for all these buffers once cooled below 0°C. A formulated IgG2 monoclonal antibody in histidine buffer with added trehalose showed the same pH behavior as the buffer itself. This antibody in various formulations was subject to freeze/thaw cycling representing a wide process (phase transition) time range, reflective of practical situations. Measurement of soluble aggregates after repeated freeze,thaw cycles shows that the change in pH was not a factor for aggregate formation in this case, which instead is governed by the presence or absence of noncrystallizing cryoprotective excipients. In the absence of a cryoprotectant, longer phase transition times lead to higher aggregation. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source]


Decline in a dominant invertebrate species contributes to altered carbon cycling in a low-diversity soil ecosystem

GLOBAL CHANGE BIOLOGY, Issue 8 2008
J. E. BARRETT
Abstract Low-diversity ecosystems cover large portions of the Earth's land surface, yet studies of climate change on ecosystem functioning typically focus on temperate ecosystems, where diversity is high and the effects of individual species on ecosystem functioning are difficult to determine. We show that a climate-induced decline of an invertebrate species in a low-diversity ecosystem could contribute to significant changes in carbon (C) cycling. Recent climate variability in the McMurdo Dry Valleys of Antarctica is associated with changes in hydrology, biological productivity, and community composition of terrestrial and aquatic ecosystems. One of the greatest changes documented in the dry valleys is a 65% decrease in the abundance of the dominant soil invertebrate (Scottnema lindsayae, Nematoda) between 1993 and 2005, illustrating sensitivity of biota in this ecosystem to small changes in temperature. Globally, such declines are expected to have significant influences over ecosystem processes such as C cycling. To determine the implications of this climate-induced decline in nematode abundance on soil C cycling we followed the fate of a 13C tracer added to soils in Taylor Valley, Antarctica. Carbon assimilation by the dry valley nematode community contributed significantly to soil C cycling (2,7% of the heterotrophic C flux). Thus, the influence of a climate-induced decline in abundance of a dominant species may have a significant effect on ecosystem functioning in a low-diversity ecosystem. [source]


Kinematics of the ACL-deficient canine knee during gait: Serial changes over two years

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2004
Scott Tashman
Abstract The ACL-deficient dog is a model for investigating the development and progression of mechanically driven osteoarthrosis of the knee. ACL loss creates dynamic instability in the ACL-deficient knee which presumably leads to progressive joint degeneration, but the nature of this instability over the time course of disease development is not well understood. The goal of this study was to characterize three-dimensional motion of the canine knee during gait, before and serially for two years after ACL transection. Canine tibial-femoral kinematics were assessed during treadmill gait before and serially for two years after ACL transection (ACL-D group; 18 dogs) or sham transection (ACL-I group; five dogs). Kinematic data was collected at 250 frames/s using a biplane video-radiographic system. Six degree-of-freedom motions of the tibia relative to the femur were calculated, and values immediately prior to pawstrike as well as the maximum, minimum, midpoint and range of motion during early/mid stance were extracted. Between-group differences relative to baseline (pre-transection) values, as well as changes over time post-transection, were determined with a repeated-measures ANCOVA. In the ACL-D group, peak anterior tibial translation (ATT) increased by 10 mm (p < 0.001), and did not change over time (p = 0.76). Pre-pawstrike ATT was similar to ACL-intact values early on (2,4 months) but then increased significantly over time, by 3.5 mm (p < 0.001). The range of ab/adduction motion nearly doubled after ACL loss (from 3.3° to 6.1°). The magnitude (midpoint) of knee adduction also increased significantly over time (mean increase 3.0°; p = 0.036). All changes occurred primarily between 6 and 12 months. There were no significant differences between groups in the transverse plane, and no significant changes over time in the ACL-I group. In summary, peak anterior tibial translation and coronal-plane instability increased immediately after ACL loss, and did not improve with time. ATT just prior to pawstrike and mean knee adduction throughout stance became progressively more abnormal with time, with the greatest changes occurring between 6 and 12 months after ACL transection. This may be due to overload failure of secondary restraints such as the medial meniscus, which has been reported to fail in a similar timeframe in the ACL-deficient dog. The relationships between these complex mechanical alterations and the rate of OA development/progression are currently under investigation. © 2004 Published by Elsevier Ltd. on behalf of Orthopaedic Research Society. [source]


Changes in plant communities over three decades on two disturbed bogs in southeastern Québec

APPLIED VEGETATION SCIENCE, Issue 1 2009
S. Pellerin
Abstract Questions: Have the natural plant communities of two mined bogs experienced changes in composition and richness over a three-decade period, and are these changes associated with anthropogenic disturbances? Location: Bas-Saint-Laurent region, southeastern Québec, Canada. Methods: We monitored three decades of floristic changes in two disturbed bogs by revisiting 57 plots in 1998, which were previously sampled in 1965 and 1966. Changes in species richness and composition were evaluated using Wilcoxon signed rank tests, principal component analysis and partial redundancy analyses (pRDA). We also used pRDA and an indicator species analysis to determine which species had undergone the greatest changes over time. Variation partitioning was used to evaluate the relative influence of human disturbance in compositional change. Results: The main changes in the vegetation of the two bogs were 1) a decrease of overall species diversity, 2) an increase in the percent cover of trees and of species tolerant of shade or drought, and 3) a decrease in the cover of heliophilous species. Picea mariana, Sphagnum fuscum and Pleurozium schreberi increased in percent cover while Chamaedaphne calyculata and Sphagnum rubellum decreased in percent cover. Variation partitioning suggested that human activities had a significant impact on vegetation composition. Conclusion: The results indicated that substantial changes occurred in the vegetation of the natural fragments of these severely disturbed bogs. Although human activities were partially responsible for the changes, our study suggested that the drying of the peat surface due to drought during the 1960s and 1980s may have contributed to the vegetation changes. [source]


Growth performances for monoculture and polyculture of hatchery-reared juvenile spotted babylon, Babylonia areolata Link, 1807, in large-scale earthen ponds

AQUACULTURE RESEARCH, Issue 14 2008
Sirusa Kritsanapuntu
Abstract This study was conducted to determine the feasibility of growing out hatchery-reared spotted babylon juvenile (Babylonia areolata) in earthen ponds. The growth, survival and water quality for monoculture of spotted babylon were compared with the two polyculture trials with sea bass (Lates calcarifer) or milkfish (Chanos chanos). This study provided good results for growth and survival of spotted babylon in earthen ponds. The mean body weight gain of snails held in the monoculture was 5.39±0.08 g, and 4.07±0.16 and 4.25±0.11 g for those held in the polyculture with sea bass or milkfish respectively. Food conversion ratios (FCR) were 2.69, 2.96 and 2.71 for snails held in the monoculture and polyculture with sea bass and milkfish, respectively, and the final survival rates were 84.94%, 74.30% and 81.20% respectively. There were no significant differences in each parameter of water quality among the treatments but significant differences among the culture period were present (P<0.05). Salinity and total alkalinity showed the greatest changes during the culture period for all treatments. Seawater temperature, pH, dissolved oxygen, nitrite,nitrogen and ammonia,nitrogen gradually changed over the culture period for all the treatments. The present study indicated the technical feasibility for monoculture and polyculture of B. areolata to marketable sizes in earthen ponds. [source]


Impacts of formaldehyde photolysis rates on tropospheric chemistry

ATMOSPHERIC SCIENCE LETTERS, Issue 1 2010
M. C. Cooke
Abstract A global chemistry transport model is employed to investigate the impact of recent laboratory determinations of photolysis parameters for formaldehyde on concentrations of tropospheric trace gases. Using the new laboratory data, the photolysis of formaldehyde is a more significant removal pathway. HOx levels are increased with the greatest changes towards the top of the troposphere and the poles, making formaldehyde a more significant source of upper tropospheric HOx than previously thought. Global totals of ozone and secondary organic aerosol increase with the rise in ozone being more significant at higher solar zenith angles. Copyright © 2010 Royal Meteorological Society [source]


Climate-driven fluctuations in surface-water availability and the buffering role of artificial pumping in an African savanna: Potential implication for herbivore dynamics

AUSTRAL ECOLOGY, Issue 7 2007
SIMON CHAMAILLÉ-JAMMES
Abstract In arid and semiarid environments surface-water strongly constrains the distribution and abundance of large herbivores during the dry season. Surprisingly, we know very little about its variability in natural ecosystems. Here we used long-term data on the dry-season occurrence of water at individual waterholes to model the surface-water availability across Hwange National Park, Zimbabwe, under contrasted climatic and management scenarios. Without artificial pumping only 19.6% of the park occurred within 5 km of water under average climatic conditions. However surface-water availability was strongly influenced by annual rainfall, and over 20 years the variability of the surface area of the park occurring within 5 km of water was slightly larger than the variability of rainfall. This contrasts with the usual buffered response of vegetation production to rainfall fluctuations, and suggests that the variability in dry-season foraging range determined by surface-water availability could be the main mechanism regulating the population dynamics of large herbivores in this environment. Artificial pumping increased surface-water availability and reduced its variability over time. Because changes in surface-water availability could cause the greatest changes in forage availability for large herbivores, we urge ecologists to investigate and report on the variability of surface-water in natural ecosystems, particularly where rapid climate changes are expected. [source]


Acidosis and Catecholamine Evaluation Following Simulated Law Enforcement "Use of Force" Encounters

ACADEMIC EMERGENCY MEDICINE, Issue 7 2010
Jeffrey D. Ho MD
ACADEMIC EMERGENCY MEDICINE 2010; 17:E60,E68 © 2010 by the Society for Academic Emergency Medicine Abstract Objectives:, Law enforcement authorities are often charged with controlling resisting suspects. These encounters sometimes result in the sudden and unexpected death of the suspect. Drug intoxication, excited delirium syndrome, or excessive uses of force are factors that are often blamed, but sometimes the mechanism of these deaths is not fully understood. It is possible that worsening acidosis or excessive catecholamine release play a part. The objective of this study was to determine the effect on markers of acidosis and catecholamines of various tasks intended to simulate common arrest-related situations. Methods:, Subjects were assigned to one of five task groups: 1) a 150-meter sprint and wall hurdle (simulated flight from arrest); 2) 45 seconds of striking a heavy bag (simulated physical resistance); 3) a 10-second TASER X26 electronic control device exposure; 4) a fleeing and resistance exercise involving a law enforcement dog (K-9); or 5) an oleoresin capsicum (OC) exposure to the face and neck. Baseline serum pH, lactate, potassium, troponin I, catecholamines, and creatine kinase (CK) were evaluated. Serum catecholamines, pH, lactate, and potassium were sampled immediately after the task and every 2 minutes for 10 minutes posttask. Vital signs were repeated immediately after the task. Serum CK and troponin I were evaluated again at 24 hours posttask. Results:, Sixty-six subjects were enrolled; four did not complete their assigned task. One subject lost the intravenous (IV) access after completing the task and did not have data collected, and one subject only received a 5-second TASER device exposure and was excluded from the study, leaving 12 subjects in each task group. The greatest changes in acidosis markers occurred in the sprint and heavy bag groups. Catecholamines increased the most in the heavy bag group and the sprint group and increased to a lesser degree in the TASER, OC, and K-9 groups. Only the sprint group showed an increase in CK at 24 hours. There were no elevations in troponin I in any group, nor any clinically important changes in potassium. Conclusions:, The simulations of physical resistance and fleeing on foot led to the greatest changes in markers of acidosis and catecholamines. These changes may be contributing or causal mechanisms in sudden custodial arrest-related deaths (ARDs). This initial work may have implications in guiding applications of force for law enforcement authorities (LEAs) when apprehending resisting subjects. [source]


2452: Patients in the DARC: drops revealing retinal ganglion cells in vivo

ACTA OPHTHALMOLOGICA, Issue 2010
MF CORDEIRO
Purpose To provide a review of current & future DARC imaging technologies and their application to neuroprotection Methods Currently, lowering IOP remains the only clinical therapy available in the treatment of glaucoma, despite the evidence that vision loss can continue in the presence of "significant" IOP reduction. Neuroprotection has been increasingly recognized as an important alternative treatment approach, but its emergence has also highlighted the need for both better defined end-points in clinical glaucoma research, as well as earlier and better detection and measures of progression. This could have been a factor in the recent memantine trial. A recent FDA/NEI meeting on end-points in glaucoma emphasized the need for new measurements. As the RGC is the primary injured neuron in this disease, it would seem logical that any modality that could directly measure RGC dysfunction and disease would be ideal. Perhaps the greatest changes that we have encountered recently are in the field of imaging technologies, which have only relatively recently been applied to the eye. Results Advances in this area have allowed unprecedented in vivo access to the retinal layers, using many different properties of light to differentiate cellular structures. DARC is a technology shortly to enter clinical trials which allows the visualization of "sick" RGCs. Conclusion Over the next few years, developments in therapy & diagnostic using DARC should offer great potential in glaucoma and other neurodegenerative conditions. Commercial interest [source]


Ophthalmic imaging today: an ophthalmic photographer's viewpoint , a review

CLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 1 2009
Timothy J Bennett FOPS
Abstract Ophthalmic imaging has changed dramatically since the 1960s with increasingly complex technologies now available. Arguably, the greatest changes have been the development of the digital camera and the speed, processing power and storage of electronic data. Already, ophthalmic practices in many major institutions overseas have paperless medium storage and electronically generated reporting from all equipment that use a computer interface. It is hard to remember the widespread use of photographic film with its attendant costs, or even to remember the days before optical coherence tomography (OCT). These latest technical improvements in ophthalmic imaging are now standard in large Australian institutions and becoming more widespread in smaller private practices. The technicians that operate and maintain this ever-increasing plethora of gadgetry have seen their work practices change from the darkroom to the complexities of data-based imaging and storage. It is a fitting time to examine the contemporary state of ophthalmic imaging and what lies on the horizon as we move towards 2020. [source]