Mixed-phase cloud physics and Southern Ocean cloud feedback in climate models

Increasing optical depth poleward of 45° is a robust response to warming in global climate models. Much of this cloud optical depth increase has been hypothesized to be due to transitions from ice-dominated to liquid-dominated mixed-phase cloud. In this study, the importance of liquid-ice partitioning for the optical depth feedback is quantified for 19 Coupled Model Intercomparison Project Phase 5 models. All models show a monotonic partitioning of ice and liquid as a function of temperature, but the temperature at which ice and liquid are equally mixed (the glaciation temperature) varies by as much as 40 K across models. Models that have a higher glaciation temperature are found to have a smaller climatological liquid water path (LWP) and condensed water path and experience a larger increase in LWP as the climate warms. The ice-liquid partitioning curve of each model may be used to calculate the response of LWP to warming. It is found that the repartitioning between ice and liquid in a warming climate contributes at least 20% to 80% of the increase in LWP as the climate warms, depending on model. Intermodel differences in the climatological partitioning between ice and liquid are estimated to contribute at least 20% to the intermodel spread in the high-latitude LWP response in the mixed-phase region poleward of 45°S. It is hypothesized that a more thorough evaluation and constraint of global climate model mixed-phase cloud parameterizations and validation of the total condensate and ice-liquid apportionment against observations will yield a substantial reduction in model uncertainty in the high-latitude cloud response to warming.

Using problem-based learning in a chemistry practical class for pharmacy students and engaging them with feedback

Objective: To introduce a new approach to problem based learning (PBL) used in the context of medicinal chemistry practical class teaching pharmacy students. Design: The described chemistry practical is based on independent studies by small groups of undergraduate students (4-5), who design their own practical work taking relevant professional standards into account. Students are carefully guided by feedback and acquire a set of skills important to their future profession as healthcare professionals. This model has been tailored to the application of PBL in a chemistry practical class setting for a large student cohort (150 students). Assessment: The achievement of learning outcomes is based on the submission of relevant documentation including a certificate of analysis, in addition to peer assessment. Some of the learning outcomes are also assessed in the final written examination at the end of the academic year. Conclusion: The described design of a novel PBL chemistry laboratory course for pharmacy students has been found to be successful. Self-reflective learning and engagement with feedback were encouraged, and students enjoyed the challenging learning experience. Skills that are highly essential for the students’ future careers as healthcare professionals are promoted.

Plastic and evolutionary responses to heat stress in a temperate dung fly: negative correlation between basal and induced heat tolerance?

Extreme weather events such as heat waves are becoming more frequent and intense. Populations can cope with elevated heat stress by evolving higher basal heat tolerance (evolutionary response) and/or stronger induced heat tolerance (plastic response). However, there is ongoing debate about whether basal and induced heat tolerance are negatively correlated and whether adaptive potential in heat tolerance is sufficient under ongoing climate warming. To evaluate the evolutionary potential of basal and induced heat tolerance, we performed experimental evolution on a temperate source 4 population of the dung fly Sepsis punctum. Offspring of flies adapted to three thermal selection regimes (Hot, Cold and Reference) were subjected to acute heat stress after having been exposed to either a hot-acclimation or non-acclimation pretreatment. As different traits may respond differently to temperature stress, several physiological and life history traits were assessed. Condition dependence of the response was evaluated by exposing juveniles to different levels of developmental (food restriction/rearing density) stress. Heat knockdown times were highest, whereas acclimation effects were lowest in the Hot selection regime, indicating a negative association between basal and induced heat tolerance. However, survival, adult longevity, fecundity and fertility did not show such a pattern. Acclimation had positive effects in heat-shocked flies, but in the absence of heat stress hot-acclimated flies had reduced life spans relative to nonacclimated ones, thereby revealing a potential cost of acclimation. Moreover, body size positively affected heat tolerance and unstressed individuals were less prone to heat stress than stressed flies, offering support for energetic costs associated with heat tolerance. Overall, our results indicate that heat tolerance of temperate insects can evolve under rising temperatures, but this response could be limited by a negative relationship between basal and induced thermotolerance, and may involve some but not other fitness-related traits.

The buck passing account of value: assessing the negative thesis

The buck-passing account of value involves a positive and a negative claim. The positive claim is that to be good is to have reasons for a pro-attitude. The negative claim is that goodness itself is not a reason for a pro-attitude. Unlike Scanlon, Parfit rejects the negative claim. He maintains that goodness is reason-providing, but that the reason provided is not an additional reason, additional, that is, to the reason provided by the good-making property. I consider various ways in which this may be understood and reject all of them. So I conclude that buck-passers cannot reject the negative claim.

Promoting behaviour change through personalized energy feedback in offices

A body of research suggests that the provision of energy feedback information to building users can elicit significant energy reductions through behaviour change. However, most studies have focused on energy use in homes and the assessment of interventions and technologies, to the neglect of the non-domestic context and broader issues arising from the introduction of feedback technologies. To address this gap, a non-domestic case study explores the delivery of personalized energy feedback to office workers through a novel system utilizing wireless technologies. The research demonstrates advantages of monitoring occupancy and quantifying energy use from specific behaviours as a basis for effective energy feedback; this is particularly important where there are highly disaggregated forms of energy use and a range of locations for that activity to take place. Quantitative and qualitative data show that personalized feedback can help individuals identify energy reduction opportunities. However, the analysis also highlights important contextual barriers and issues that need to be addressed when utilizing feedback technologies in the workplace. If neglected, these issues may limit the effective take-up of feedback interventions.

Closed-loop feedback computation model of dynamical reputation based on the local trust evaluation in business-to-consumer e-commerce

Trust and reputation are important factors that influence the success of both traditional transactions in physical social networks and modern e-commerce in virtual Internet environments. It is difficult to define the concept of trust and quantify it because trust has both subjective and objective characteristics at the same time. A well-reported issue with reputation management system in business-to-consumer (BtoC) e-commerce is the “all good reputation” problem. In order to deal with the confusion, a new computational model of reputation is proposed in this paper. The ratings of each customer are set as basic trust score events. In addition, the time series of massive ratings are aggregated to formulate the sellers’ local temporal trust scores by Beta distribution. A logical model of trust and reputation is established based on the analysis of the dynamical relationship between trust and reputation. As for single goods with repeat transactions, an iterative mathematical model of trust and reputation is established with a closed-loop feedback mechanism. Numerical experiments on repeated transactions recorded over a period of 24 months are performed. The experimental results show that the proposed method plays guiding roles for both theoretical research into trust and reputation and the practical design of reputation systems in BtoC e-commerce.

The effect of targeting tolerance of children's negative emotions among anxious parents of children with anxiety disorders: a pilot randomised controlled trial

Following cognitive behavioural therapy for child anxiety a significant minority of children fail to lose their diagnosis status. One potential barrier is high parental anxiety. We designed a pilot RCT to test claims that parental intolerance of the child’s negative emotions may impact treatment outcomes. Parents of 60 children with an anxiety disorder, who were themselves highly anxious, received either brief parent-delivered treatment for child anxiety or the same treatment with strategies specifically targeting parental tolerance of their child’s negative emotions. Consistent with predictions, parental tolerance of the child’s negative emotions significantly improved from pre- to post-treatment. However, there was no evidence to inform the direction of this association as improvements were substantial in both groups. Moreover, while there were significant improvements in child anxiety in both conditions, there was little evidence that this was associated with the improvement in parental tolerance. Nevertheless, findings provide important clinical insight, including that parent-led treatments are appropriate even when the parent is highly anxious and that it may not be necessary to adjust interventions for many families.

Revascularization and periapical repair after endodontic treatment using apical negative pressure irrigation versus conventional irrigation plus triantibiotic intracanal dressing in dogs` teeth with apical periodontitis

Objective. The objective of this study was to evaluate in vivo the revascularization and the apical and periapical repair after endodontic treatment using 2 techniques for root canal disinfection (apical negative pressure irrigation versus apical positive pressure irrigation plus triantibiotic intracanal dressing) in immature dogs` teeth with apical periodontitis. Study design. Two test groups of canals with experimentally induced apical periodontitis were evaluated according to the disinfection technique: Group 1, apical negative pressure irrigation (EndoVac system), and Group 2, apical positive pressure irrigation (conventional irrigation) plus triantibiotic intracanal dressing. In Group 3 (positive control), periapical lesions were induced, but no endodontic treatment was done. Group 4 (negative control) was composed of sound teeth. The animals were killed after 90 days and the maxillas and mandibles were subjected to histological processing. The sections were stained with hematoxylin and eosin and Mallory Trichrome and examined under light microscopy. A description of the apical and periapical features was done and scores were attributed to the following histopathological parameters: newly formed mineralized apical tissue, periapical inflammatory infiltrate, apical periodontal ligament thickness, dentin resorption, and bone tissue resorption. Intergroup comparisons were done by the Kruskal-Wallis and Dunn`s tests (alpha = 0.05). Results. Although statistically significant difference was found only for the inflammatory infiltrate (P < .05), Group 1 presented more exuberant mineralized formations, more structured apical and periapical connective tissue, and a more advanced repair process than Group 2. Conclusion. From the histological observations, sodium hypochlorite irrigation with the EndoVac system can be considered as a promising disinfection protocol in immature teeth with apical periodontitis, suggesting that the use of intracanal antibiotics might not be necessary. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: 779-787)

Apical negative pressure irrigation versus conventional irrigation plus triantibiotic intracanal dressing on root canal disinfection in dog teeth

Objective. The aim of this study was to compare in vivo the efficacy of 2 root canal disinfection techniques (apical negative pressure irrigation versus apical positive pressure irrigation plus triantibiotic intracanal dressing) in immature dog teeth with apical periodontitis. Study design. Two groups of root canals with pulp necrosis and apical periodontitis were evaluated according to the disinfection technique: group 1: apical negative pressure irrigation (EndoVac system); and group 2: apical positive pressure irrigation (conventional irrigation) plus triantibiotic intracanal dressing. The first sample (S1) was collected after lesions were radiographically visible, and the second sample (S2) was collected after apical negative pressure irrigation (group 1) or conventional irrigation/triantibiotic dressing (group 2). All samples were seeded in a culture medium for anaerobic bacteria. Colony-forming unit counts were analyzed statistically by the Mann-Whitney test (alpha = .05). Results. Microorganisms were present in 100% of canals of both groups in S1. In S2, microorganisms were absent in 88.6% of group 1`s canals and 78.28% of group 2`s canals. There was no significant difference between the groups in either S1 (P = .0963) or S2 (P = .0566). There was significant (P < .05) bacterial reduction from S1 to S2 in both groups. Conclusion. In immature teeth with apical periodontitis, use of the EndoVac system can be considered to be a promising disinfection protocol, because it provided similar bacterial reduction to that of apical positive pressure irrigation (conventional irrigation) plus intracanal dressing with the triantibiotic paste, and the use of intracanal antibiotics might not be necessary. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109:e42-e46)

Lineage-Negative Bone Marrow Cells Protect Against Chronic Renal Failure

Progressive renal failure continues to be a challenge. The use of bone marrow cells represents a means of meeting that challenge. We used lineage-negative (Lin(-)) cells to test the hypothesis that Lin(-) cell treatment decreases renal injury. Syngeneic Fischer 344 rats were divided into four groups: sham ( laparotomy only, untreated); Nx (five-sixth nephrectomy and untreated); NxLC1 (five-sixth nephrectomy and receiving 2 x 10(6) Lin(-) cells on postnephrectomy day 15); and NxLC3 (five-sixth nephrectomy and receiving 2 x 10(6) Lin(-) cells on postnephrectomy days 15, 30, and 45). On postoperative day 16, renal mRNA expression of interleukin (IL)-1 beta, tumor necrosis factor-alpha, and IL-6 was lower in NxLC rats than in Nx rats. On postnephrectomy day 60, NxLC rats presented less proteinuria, glomerulosclerosis, anemia, renal infiltration of immune cells, and protein expression of monocyte chemoattractant protein-1, as well as decreased interstitial area. Immunostaining for proliferating cell nuclear antigen showed that, in comparison with sham rats, Nx rats presented greater cell proliferation, whereas NxLC1 rats and NxLC3 rats presented less cell proliferation than did Nx rats. Protein expression of the cyclin-dependent kinase inhibitor p21 and of vascular endothelial growth factor increased after nephrectomy and decreased after Lin(-) cell treatment. On postnephrectomy day 120, renal function (inulin clearance) was significantly better in Lin(-) cell-treated rats than in untreated rats. Lin(-) cell treatment significantly improved survival. These data suggest that Lin(-) cell treatment protects against chronic renal failure. STEM CELLS 2009; 27: 682-692

Negative anticipatory contrast: Does it involve anticipation of an impending reward?

Negative anticipatory contrast (NAC) corresponds to the suppression in consumption of a first rewarding substance (e.g., saccharin 0.15%) when it is followed daily by a second preferred substance (e.g., sucrose 32%). The NAC has been interpreted as resulting from anticipation of the impending preferred reward and its comparison with the currently available first reward [Flaherty, CF., Rowan, G.A., 1985. Anticipatory contrast: within-subjects analysis. Anim. Learn. Behav. 13, 2-5]. In this context, one should expect that devaluation of the preferred substance after the establishment of the NAC would either reduce or abolish the contrast effect. However, contrary to this prediction, the results of the present study show that the NAC is insensitive to devaluation of the second, preferred, substance. This allows one to question that interpretation. The results reported in this study support the view that the NAC effect is controlled by memory of the relative value of the first solution, which is updated daily by means of both a gustatory and/or post-ingestive comparison of the first and second solutions, and memory of past pairings. (C) 2010 Elsevier B.V. All rights reserved.

The Ventral Premammillary Nucleus Links Fasting-Induced Changes in Leptin Levels and Coordinated Luteinizing Hormone Secretion

Physiological conditions of low leptin levels like those observed during negative energy balance are usually characterized by the suppression of luteinizing hormone (LH) secretion and fertility. Leptin administration restores LH levels and reproductive function. Leptin action on LH secretion is thought to be mediated by the brain. However, the neuronal population that mediates this effect is still undefined. The hypothalamic ventral premammillary nucleus (PMV) neurons express a dense concentration of leptin receptors and project to brain areas related to reproductive control. Therefore, we hypothesized that the PMV is well located to mediate leptin action on LH secretion. To test our hypothesis, we performed bilateral excitotoxic lesions of the PMV in adult female rats. PMV-lesioned animals displayed a clear disruption of the estrous cycle, remaining in anestrus for 15-20 d. After apparent recovery of cyclicity, animals perfused in the afternoon of proestrus showed decreased Fos immunoreactivity in the anteroventral periventricular nucleus and in gonadotropin releasing hormone neurons. PMV-lesioned animals also displayed decreased estrogen and LH secretion on proestrus. Lesions caused no changes in mean food intake and body weight up to 7 weeks after surgery. We further tested the ability of leptin to induce LH secretion in PMV-lesioned fasted animals. We found that complete lesions of the PMV precluded leptin stimulation of LH secretion on fasting. Our findings demonstrate that the PMV is a key site linking changing levels of leptin and coordinated control of reproduction.

Arachidonic acid actions on functional integrity and attenuation of the negative effects of palmitic acid in a clonal pancreatic beta-cell line

Chronic exposure of pancreatic beta-cells to saturated non-esterified fatty acids can lead to inhibition of insulin secretion and apoptosis. Several previous studies have demonstrated that saturated fatty acids such as PA (palmitic acid) are detrimental to beta-cell function compared with unsaturated fatty acids. In the present study, we describe the effect of the polyunsaturated AA (arachidonic acid) on the function of the clonal pancreatic beta-cell line BRIN-BD11 and demonstrate AA-dependent attenuation of PA effects. When added to beta-cell incubations at 100 mu M, AA can stimulate cell proliferation and chronic (24 h) basal insulin secretion. Microarray analysis and/or real-time PCR indicated significant AA-dependent up-regulation of genes involved in proliferation and fatty acid metabolism [e.g. Angptl (angiopoietin-like protein 4), Ech1 (peroxisomal Delta(3.5),Delta(2.4)-dienoyl-CoA isomerase), Cox-1 (cyclo-oxygenase-1) and Cox-2, P < 0.05]. Experiments using specific COX and LOX (lipoxygenase) inhibitors demonstrated the importance of COX-1 activity for acute (20 min) stimulation of insulin secretion, suggesting that AA metabolites may be responsible for the insulinotropic effects. Moreover, concomitant incubation of AA with PA dose-dependently attenuated the detrimental effects of the saturated fatty acid, so reducing apoptosis and decreasing parameters of oxidative stress [ROS (reactive oxygen species) and NO levels] while improving the GSH/GSSG ratio. AA decreased the protein expression of iNOS (inducible NO synthase), the p65 subunit of NF-kappa B (nuclear factor kappa B) and the p47 subunit of NADPH oxidase in PA-treated cells. These findings indicate that AA has an important regulatory and protective beta-cell action, which may be beneficial to function and survival in the `lipotoxic` environment commonly associated with Type 2 diabetes mellitus.