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Causal Link (causal + link)
Selected AbstractsDO THE 10 UK SUICIDES AMONG THOSE TAKING THE SMOKING CESSATION DRUG VARENICLINE SUGGEST A CAUSAL LINK?ADDICTION, Issue 5 2009JOHN STAPLETON No abstract is available for this article. [source] Causal Links between Brain Cytokines and Experimental Febrile Convulsions in the RatEPILEPSIA, Issue 12 2005James G. Heida Summary:,Purpose: Despite the prevalence of febrile convulsions (FCs), their pathophysiology has remained elusive. We tested the hypothesis that components of the immune response, particularly the proinflammatory cytokine interleukin-1, (IL-1,) and its naturally occurring antagonist interleukin-1 receptor antagonist (IL-1ra) may play a role in the genesis of FC. Methods: Postnatal day 14 rats were treated with lipopolysaccharide (LPS; 200 ,g/kg, i.p.) followed by a subconvulsant dose of kainic acid (1.75 mg/kg, i.p.). Brains were harvested at and 2 h after onset of FCs to measure brain levels of IL-1, and IL-1ra. Separate groups of animals were given intracerebroventricular (ICV) injections of IL-1,, or IL-1ra in an attempt to establish a causal relation between the IL-1,/IL-1ra system and FCs. Results: Animals with FCs showed increased IL-1, in the hypothalamus and hippocampus but not in the cortex compared with noFC animals that also received LPS and kainic acid. This increase was first detected in the hippocampus at onset of FCs. No detectable difference in IL-1ra was found in brain regions examined in either group. When animals were treated with IL-1, ICV, a dose-dependant increase was noted in the proportion of animals that experienced FCs, whereas increasing doses of IL-1ra, given to separate groups of animals, were anticonvulsant. Conclusions: Our results suggest that excessive amounts of IL-1, may influence the genesis of FCs. This may occur by overproduction of IL-1,, or by alteration in the IL-1,/IL-1ra ratio in the brain after an immune challenge. [source] Causal Links Between Financial Activity and Economic Growth: Empirical Evidence from a Cross,Country Analysis, 1970,1990BULLETIN OF ECONOMIC RESEARCH, Issue 2 2002Michael Graff To clarify the causal links between financial activity and economic growth, a series of path models is estimated. It is shown that during the 1970s and 1980s finance was predominantly a supply,leading determinant of economic growth. The data suggest, however, that there has been a structural change and that from about 1975,80, finance was far less beneficial , and possibly even detrimental , to growth. [source] Causal link between neonatal hydronephrosis and later development of hypertensionCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2 2010Mattias Carlström Summary 1. Although congenital ureteral obstruction is a common disorder in infants, its pathophysiology remains poorly understood and its clinical management continues to be debated. During the past decade, the surgical management of non-symptomatic hydronephrosis in children has become more conservative, but the long-term physiological consequences of this new policy are unclear. 2. In experimental models with complete ureteral obstruction, tubular atrophy and interstitial inflammation occur rapidly. Although this type of obstruction is very rare in clinical practice, it is often referred to in clinical discussions. New studies, using a model with chronic partial ureteral obstruction, have demonstrated that hydronephrosis is associated with renal injuries and is causally related to hypertension. 3. The mechanisms underlying the development of hypertension in experimental hydronephrosis are complex and involve changes in both the renin,angiotensin system and renal sympathetic nerve activity. Furthermore, oxidative stress and nitric oxide deficiency in the diseased kidney, with consequent resetting of the tubuloglomerular feedback mechanism, appear to play a pivotal role in the development and maintenance of hyper-tension. 4. In view of the new knowledge regarding the long-term effects of partial ureteral obstruction, today's non-operative management of hydronephrosis should be reconsidered to prevent obstructive nephropathy and hypertension in later life. [source] Patterns of abundance of fire ants and native ants in a native ecosystemECOLOGICAL ENTOMOLOGY, Issue 4 2009KATHARINE L. STUBLE Abstract 1.,This correlational study examines the relationship between the red imported fire ant (Solenopsis invicta) and native ants in a longleaf pine savanna. Fire ants are frequently associated with a decline in native ants throughout the invaded range, but fire ant invasion is often coupled with habitat disturbance. Invasion of fire ants into the longleaf pine savanna provides an opportunity to examine the structure of the ant community in the absence of habitat disturbance. 2.,Pitfall trapping was conducted within the longleaf pine savanna as well as across a naturally occurring soil moisture gradient, in plots that had been artificially watered. 3.,Species richness did not vary as a function of fire ant density. There was an inverse relationship between native ant density and fire ant density, but this abundance pattern does not necessarily imply a causal link between fire ant invasion and native ant decline. For individual species, fire ant densities were negatively correlated with the densities of only two native ant species, including Solenopsis carolinensis, a native species that potentially limits the invasion of fire ants. Additionally, fire ants and native ants respond differently to soil moisture, with native ants favouring drier conditions than fire ants. 4.,The possible exclusion of fire ants by some native ants, as well as differences in habitat preferences, provide alternative explanations for the frequently observed negative correlation between fire ants and native ants. [source] Human sewage identified as likely source of white pox disease of the threatened Caribbean elkhorn coral, Acropora palmataENVIRONMENTAL MICROBIOLOGY, Issue 5 2010Kathryn Patterson Sutherland Summary Caribbean elkhorn coral, Acropora palmata, has been decimated in recent years, resulting in the listing of this species as threatened under the United States Endangered Species Act. A major contributing factor in the decline of this iconic species is white pox disease. In 2002, we identified the faecal enterobacterium, Serratia marcescens, as an etiological agent for white pox. During outbreaks in 2003 a unique strain of S. marcescens was identified in both human sewage and white pox lesions. This strain (PDR60) was also identified from corallivorious snails (Coralliophila abbreviata), reef water, and two non-acroporid coral species, Siderastrea siderea and Solenastrea bournoni. Identification of PDR60 in sewage, diseased Acropora palmata and other reef invertebrates within a discrete time frame suggests a causal link between white pox and sewage contamination on reefs and supports the conclusion that humans are a likely source of this disease. [source] Attention Deficit Hyperactivity Disorder and substance use disorders: is there a causal link?ADDICTION, Issue 6 2001Michael T. Lynskey Attention-deficit hyperactivity disorder (ADHD), characterized by restless, inattentive and hyperactive behaviours, is a relatively common childhood disorder that affects approximately 5% of the general population. There has been controversy about whether ADHD increases risks of developing substance use disorders. The available evidence suggests that, in the absence of conduct disorder, ADHD is not associated with an increased risk of substance use problems in males. There is only limited evidence on the role of ADHD in the aetiology of substance use disorders among females. While ADHD has traditionally been considered as a childhood disorder, it may also occur in adults; research needs to examine the extent to which ADHD in adulthood increases the risk of substance use disorders. [source] Genetic determinants of adult hippocampal neurogenesis correlate with acquisition, but not probe trial performance, in the water maze taskEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2002G. Kempermann Abstract A number of reports have indicated that adult neurogenesis might be involved in hippocampal function. While increases in adult neurogenesis are paralleled by improvements on learning tasks and learning itself can promote the survival of newly generated neurons in the hippocampus, a causal link between learning processes and adult hippocampal neurogenesis is difficult to prove. Here, we addressed the related question of whether the baseline level of adult neurogenesis is predictive of performance on the water maze task as a test of hippocampal function. We used ten strains of recombinant inbred mice, based on C57BL/6, which are good learners and show high baseline levels of neurogenesis, and DBA/2, which are known to be poor learners and which exhibit low levels of adult neurogenesis. Two of these strains, BXD-2 and BXD-8, showed a 26-fold difference in the number of newly generated neurons per hippocampus. Over all strains, including the parental strains, there was a significant correlation between the number of new neurons generated in the dentate gyrus and parameters describing the acquisition of the water maze task (slope of the learning curves). Similar results were seen when the parental strains were not included in the analysis. There was no correlation between adult hippocampal neurogenesis and probe trial performance, performance on the rotarod, overall locomotor activity, and baseline serum corticosterone levels. This result supports the hypothesis that adult neurogenesis is involved in specific aspects of hippocampal function, particularly the acquisition of new information. [source] Asset Opaqueness and Split Bond RatingsFINANCIAL MANAGEMENT, Issue 3 2007Miles Livingston Professor of Finance We examine the relation between asset opaqueness and split ratings. We find that firms with asset opaqueness problems are more likely to receive split bond ratings from Moody s and S&P rating agencies. Our results suggest that there is a causal link between asset opaqueness and split ratings. [source] Does female nuptial coloration reflect egg carotenoids and clutch quality in the Two-Spotted Goby (Gobiusculus flavescens, Gobiidae)?FUNCTIONAL ECOLOGY, Issue 4 2006P. A. SVENSSON Summary 1Carotenoid-based ornamentation has often been suggested to signal mate quality, and species with such ornaments have frequently been used in studies of sexual selection. 2Female Gobiusculus flavescens (Two-Spotted Goby) develop colourful orange bellies during the breeding season. Belly coloration varies among mature females, and previous work has shown that nest-holding males prefer females with more colourful bellies. Because males invest heavily in offspring during incubation, the evolution of this preference can be explained if colourful females provide males with eggs of higher quality. 3We tested this hypothesis by allowing males to spawn with ,colourful' and ,drab' females and comparing parameters including egg carotenoid concentration, clutch size, hatchability and larval viability between groups. We also investigated relationships between egg carotenoid concentration and clutch quality parameters. 4Eggs from colourful females had significantly higher concentrations of total carotenoids than drab females, and photographically quantified belly coloration was a good predictor of egg carotenoid concentration. 5Colourful females produced slightly larger clutches, but female belly coloration was not related to any measure of clutch quality. In addition, there were no significant relationships between egg carotenoids and clutch quality. Females with high levels of egg carotenoids spawned slightly earlier, however, possibly because they were more ready to spawn or because of male mate choice. 6Our results call into question the generality of a causal link between egg carotenoids and offspring quality. [source] The fate of the homoctenids (Tentaculitoidea) during the Frasnian,Famennian mass extinction (Late Devonian)GEOBIOLOGY, Issue 3 2006DAVID BONDArticle first published online: 18 AUG 200 ABSTRACT The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals that are among the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian,Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian,Famennian boundary sections have been studied, in Poland, Germany, France, and the USA. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian ,Upper Kellwasser Event'. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F-F extinction. Most notable is the sudden demise of a group, which had been present in rock-forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here. [source] Job displacement and stress-related health outcomesHEALTH ECONOMICS, Issue 10 2006Martin Browning Abstract We investigate whether job loss as the result of displacement causes hospitalization for stress-related diseases which are widely thought to be associated with unemployment. In doing this, we use much better data than any previous investigators. Our data are a random 10% sample of the male population of Denmark for the years 1981,1999 with full records on demographics, health and work status for each person, and with a link from every working person to a plant. We use the method of ,matching on observables' to estimate the counter-factual of what would have happened to the health of a particular group of displaced workers if they had not in fact been displaced. Our results indicate unequivocally that being displaced in Denmark does not cause hospitalization for stress-related disease. An analysis of the power of our test suggests that even though we are looking for a relatively rare outcome, our data set is large enough to show even quite small an effect if there were any. Supplementary analyses do not show any causal link from displacement or unemployment to our health outcomes for particular groups that might be thought to be more susceptible. Copyright © 2006 John Wiley & Sons, Ltd. [source] Is there a causal link between currency and debt crises?INTERNATIONAL JOURNAL OF FINANCE & ECONOMICS, Issue 4 2006Axel Dreher Abstract Though currency and debt crises quite often occur simultaneously, the links between these two types of crises are not well understood. We review how currency and debt crises could be related due to common causes, contagion effects from one crisis to the other, and complementary budget financing aspects. In an empirical analysis based on a panel of 80 countries over the period 1975,2000, we first investigate the determinants of each crisis separately. Then we estimate links between both crises employing instrumental variables techniques. We find that, while there is a negative lagged influence of currency crises on debt crises, currency crises significantly increase the risk of contemporaneous debt crises and vice versa. Copyright © 2006 John Wiley & Sons, Ltd. [source] A sceptical view of climate change and water resources planningIRRIGATION AND DRAINAGE, Issue 3 2001Geoff Kite changement du climat; l'aménagement des ressources en eau Abstract Journals, both academic and otherwise, are full of papers describing in detail the impacts of climate change, and a presumed causal link to man's activities, especially the contribution of "greenhouse gases". Despite the abundance of funding to study the hypothesised anthropogenic link, it has yet to be demonstrated, while evidence to the contrary can readily be derived from available data. This brief paper summarises some information that may give cause for thought and suggests that environmental degradation should be of more concern than an imaginary climate change. Copyright © 2001 John Wiley & Sons, Ltd. Aujourd'hui les journaux (scientifiques inclus) sont pleins d'articles qui décrivent en détail les effets du changement du climat et qui présentent ses effets comme un résultat des activités anthromorphiques, en particulier notre effet sur les "greenhouse gases". Même avec tout l'argent dépensé de ces études, il n'y a aucune évidence pour cette hypothèse. Au contraire, les données suggèrent que le changement actuel du climat est, pour la grande plupart, naturel. Cet article bref donne un point de vue un peu différent qui constate, en bréf, que bien sûr il y a toujours des changements du climat mais pour l'aménagement des ressources en eau il y a, au moins, un problème plus important. Copyright © 2001 John Wiley & Sons, Ltd. [source] Diversity,stability relationships in multitrophic systems: an empirical explorationJOURNAL OF ANIMAL ECOLOGY, Issue 5 2003Priyanga Amarasekare Summary 1The relationship between diversity and stability is crucial in understanding the dynamics of multitrophic interactions. There are two basic hypotheses about the causal link between diversity and stability. The first is that fluctuations in resource abundance allow consumer coexistence, thus increasing diversity at the consumer trophic level (resource variability hypothesis). The second is that interactions between coexisting consumer species reduce consumer efficiency and dampen population fluctuations, thus increasing consumer,resource stability (consumer efficiency hypothesis). 2The two hypotheses lead to three comparative predictions: (i) fluctuations should be greater (resource variability) or smaller (consumer efficiency) in resource populations with coexisting consumer species, compared to those invaded only by the consumer species superior at resource exploitation; (ii) average resource abundance should be greater (resource variability) or smaller (consumer efficiency) in resource populations with greater fluctuations; and (iii) removal of the consumer species inferior at resource exploitation should increase or not affect resource population fluctuations (resource variability), or always increase them (consumer efficiency). 3I tested these predictions with data from a host,multiparasitoid community: the harlequin bug (Murgantia histrionica) and two specialist parasitoids (Trissolcus murgantiae and Ooencyrtus johnsonii) that attack the bug's eggs. 4Local host populations with coexisting parasitoids exhibited smaller fluctuations and greater average abundance compared to those with just Trissolcus, the species superior at host exploitation. Local populations that lost Ooencyrtus, the species inferior at host exploitation, exhibited an increase in host population fluctuations compared to those that did not. 5The results contradict the expectations of the resource variability hypothesis, suggesting that host population fluctuations are unlikely to be driving parasitoid coexistence. They are consistent with the consumer efficiency hypothesis, that interactions between coexisting parasitoid species dampens host population fluctuations. I discuss the implications of these results as well as possible caveats. [source] Could mindfulness decrease anger, hostility, and aggression by decreasing rumination?AGGRESSIVE BEHAVIOR, Issue 1 2010Ashley Borders Abstract Research suggests that rumination increases anger and aggression. Mindfulness, or present-focused and intentional awareness, may counteract rumination. Using structural equation modeling, we examined the relations between mindfulness, rumination, and aggression. In a pair of studies, we found a pattern of correlations consistent with rumination partially mediating a causal link between mindfulness and hostility, anger, and verbal aggression. The pattern was not consistent with rumination mediating the association between mindfulness and physical aggression. Although it is impossible with the current nonexperimental data to test causal mediation, these correlations support the idea that mindfulness could reduce rumination, which in turn could reduce aggression. These results suggest that longitudinal work and experimental manipulations mindfulness would be worthwhile approaches for further study of rumination and aggression. We discuss possible implications of these results. Aggr. Behav. 36:28,44, 2010. © 2009 Wiley-Liss, Inc. [source] Predation by brown trout: a major mortality factor for sexually mature European minnowsJOURNAL OF FISH BIOLOGY, Issue 3 2003J. Museth Brown trout Salmo trutta in the subalpine lake, Øvre Heimdalsvatn, showed large temporal variation in the rate of predation on the introduced minnow Phoxinus phoxinus population. Minnows were found in the stomachs of brown trout between 16 and 38 cm LT. Significantly greater predation was recorded shortly after ice break at the end of June 1999, with frequencies of 9 and 20% within the LT classes 16,29·9 cm and ,30 cm, respectively. Predation on minnows was only occasionally detected during July, August and September. The high level of predation coincided with minnow spawning, and lengths of consumed minnows were equal to those of sexually mature individuals. Accepting a causal link between minnow spawning, which lasted c. 3 weeks, and the contemporary high rate of predation, the estimated annual consumption of minnows by the brown trout population would be 138 kg wet mass. Although most of the annual consumption of minnows by brown trout (90%) occurred within a very short period (3 weeks), it accounted for a significant proportion (60%) of the annual loss in biomass of the sexually mature part of the population. [source] The emergence period of sea trout fry in a Lake District stream correlates with the North Atlantic OscillationJOURNAL OF FISH BIOLOGY, Issue 1 2000J.M. Elliott The date of fry emergence over 30 years in a sea trout nursery stream, predicted by an individual-based model, correlated significantly (r=0·660, P<0·001) with an index of the North Atlantic Oscillation. Water temperature is the main driving variable in the model and stream temperature also correlated significantly (r=0·662, P<0·001) with the index, providing a probable causal link. Therefore, the inter-annual variations in emergence may not be unique to this one stream, but may be typical of other trout streams with similar climatic conditions. [source] Children at Risk: Legal and Societal Perceptions of the Potential Threat that the Possession of Child Pornography Poses to SocietyJOURNAL OF LAW AND SOCIETY, Issue 3 2002Suzanne Ost This article examines legal and social discourses surrounding the phenomenon of child pornography, considering the legal responses to child pornography (particularly when an individual is found to be in possession of such material), and the way in which such material, the child, and the possessor of child pornography are socially constructed. The article raises the question of whether there has been a moral panic regarding child pornography and the possession of such material, but also considers whether there are real reasons to consider that the possession of child pornography should remain illegal. Research studies which aim to establish the existence of a causal link between possessing child pornography and the act of committing child sexual abuse are examined, as is the argument that criminalizing the possession of child pornography reduces the market for such material. Finally, there is an analysis of the possible impact of social constructions of the child as innocent. [source] Outcome of pregnancy after laser conization: Implications for infection as a causal link with preterm birthJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 5 2008Hitoshi Masamoto Abstract Objective:, To investigate a causal link between infection and preterm birth in women with a shortened cervix induced by prior laser conization. Methods:, We conducted a retrospective review of the outcomes of 47 singleton pregnancies with a history of laser conization. Cervical length was measured between 17 and 23 weeks of gestation. Receiver-operating characteristic curves were used to determine the best cut-off point for the cervical length for predicting spontaneous preterm birth. We measured infectious markers in 12 women who had experienced preterm labor. Results:, Nine women had had premature labors and three had had late abortions. The mean ± SD cervical length was 33.1 ± 9.1 mm. The optimal cut-off for predicting preterm delivery was 25 mm with a sensitivity and specificity of 75.0% and 97.1%, respectively. Concentrations of granulocyte elastase were positive in five of the six samples determined. The white blood cell count and C-reactive protein levels were elevated in four out of the six patients. Sixty-seven percent of the vaginal cultures were positive for bacteria. Chorioamnionitis was present in seven women. Conclusions:, For the prediction of preterm birth in patients with a history of conization, it is helpful to look for signs of local infection when the cervical length is less than 25 mm. [source] Evidence for a causal association between oral polio vaccine and transverse myelitis: A case history and review of the LiteratureJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 4 2006Heath Kelly Abstract: A 6-month-old boy developed transverse myelitis 7 days after the receipt of oral polio vaccine (OPV). A paediatric neurologist confirmed the diagnosis when the boy was aged 9 years. The boy had received his first scheduled OPV at the age of 4 months and had developed immunity to serotypes 1 and 2 but not to serotype 3. A poliovirus type 3 was isolated from stool and throat specimens collected from the boy in the first 2 days after symptom onset. This was shown, in a World Health Organization accredited laboratory, to be a vaccine strain by nucleic acid probe hybridiztion and enzyme-linked immunosorbent assay. The boy subsequently developed immunity to poliovirus serotype 3. It is accepted that poliovirus infection can present occasionally as transverse myelitis. This is estimated to occur in 1:125,1:800 cases. It is also accepted that OPV can cause vaccine-associated paralytic polio with a frequency of approximately one case per 2.5 million doses of OPV distributed. It seems feasible therefore that OPV could cause transverse myelitis with a frequency of 1 in 300 million to one in two billion doses distributed. In a 1993 report from the Institute of Medicine of the National Acadamies of the United States pertaining to vaccine safety, theoretical criteria were advanced for the establishment of a causal relationship between a vaccine and a clinical outcome. The clinical history and laboratory results in this case satisfy these criteria, providing plausible evidence for the causal link between OPV and transverse myelitis. [source] Does sex education affect adolescent sexual behaviors and health?JOURNAL OF POLICY ANALYSIS AND MANAGEMENT, Issue 4 2006Joseph J. SabiaArticle first published online: 6 SEP 200 This study examines whether offering sex education to young teenagers affects several measures of adolescent sexual behavior and health: virginity status, contraceptive use, frequency of intercourse, likelihood of pregnancy, and probability of contracting a sexually transmitted disease. Using data from the National Longitudinal Study of Adolescent Health, I find that while sex education is associated with adverse health outcomes, there is little evidence of a causal link after controlling for unobserved heterogeneity via fixed effects and instrumental variables. These findings suggest that those on each side of the ideological debate over sex education are, in a sense, both correct and mistaken. Opponents are correct in observing that sex education is associated with adverse health outcomes, but are generally incorrect in interpreting this relationship causally. Proponents are generally correct in claiming that sex education does not encourage risky sexual activity, but are incorrect in asserting that investments in typical schoolbased sex education programs produce measurable health benefits. © 2006 by the Association for Public Policy Analysis and Management [source] Does early adolescent sex cause depressive symptoms?JOURNAL OF POLICY ANALYSIS AND MANAGEMENT, Issue 4 2006Joseph J. Sabia A recent study by the Heritage Foundation (Rector, Johnson, & Noyes, 2003) found evidence of a positive relationship between early sexual intercourse and depressive symptoms. This finding has been used to bolster support for funding abstinenceonly sex education. However, promoting abstinence will only yield mental health benefits if there is a causal link between sexual intercourse and depression. Using the National Longitudinal Study of Adolescent Health (Add Health), I carefully examine the relationship between early teen sex and several measures of depression. Controlling for a wide set of individuallevel and familylevel observable characteristics, crosssection estimates consistently show a significant positive relationship between early sexual activity for females and three measures of adverse mental health: selfreported depression, a belief that one's life is not worth living, and serious thoughts of suicide. However, differenceindifference estimates reflect no evidence of a significant relationship between early teen sex and depressive symptoms. These findings suggest that the positive association observed by Rector et al. (2003) can be explained by unmeasured heterogeneity. Thus, promoting abstinence among adolescents is unlikely to alleviate depressive symptoms.© 2006 by the Association for Public Policy Analysis and Management. [source] Outcome of patients with hepatocellular carcinoma referred to a tertiary centre with availability of multiple treatment options including cadaveric liver transplantationLIVER INTERNATIONAL, Issue 9 2007John F. Perry Abstract Hepatocellular carcinoma (HCC) is a primary cancer of the liver with an established causal link to viral hepatitis and other forms of chronic liver disease. Aims: The aim of this study was to analyse the determinants of outcome in patients with HCC referred to a tertiary centre for management. Method: Two hundred and thirty-five prospective patients with HCC and minimum 12-month follow-up were studied. Results: The cohort was heterogeneous, with 52% Caucasian, 40% Asian and 5% of Middle-Eastern origin. Independent predictors of outcome included tumour size and number, the presence of ascites or portal vein thrombosis, ,-foetoprotein >50 U/L and an impaired performance status. Treatment was determined on an individual case basis by a multidisciplinary tumour team. Surgical resection was primary treatment in 43 patients, liver transplantation in 40 patients, local ablation (percutaneous radiofrequency ablation or alcohol injection) in 33 patients, transarterial chemoembolisation in 33 patients, chemotherapy or other systemic therapy in 30 patients and no treatment in 56 patients. After adjustment for significant covariates, both liver transplantation (P<0.001) and surgical resection (P=0.029) had a significant effect on patient survival compared with no treatment, but local ablation (P=0.410) and chemoembolisation (P=0.831) did not. Liver transplantation resulted in superior overall and, in particular, disease-free survival compared with surgical resection (disease-free survival 84 vs 15% at 5 years). Conclusion: In conclusion, both surgical resection and liver transplantation significantly improve the survival of patients with HCC, but improvements need to be made to the delivery of loco-regional therapy to enhance its effectiveness. [source] Endogenous Money: What it is and Why it MattersMETROECONOMICA, Issue 2 2002Thomas I. Palley Endogenous money is widespread in economic theory. The post-Keynesian contribution is identification of a causal link between bank lending and the money supply. Though driven by macroeconomic concerns, the post-Keynesian debate has reduced to a microeconomic debate over the role of financial intermediaries in the accommodation process. In the IS,LM model endogenous money flattens the LM. This misses its substantive significance which is the discrediting of monetarist money supply policy rules and monetarist critiques of central banking, its identification of the key role of credit, and its provision of a credit-driven theory of the business cycle. [source] Rhythms of Mental PerformanceMIND, BRAIN, AND EDUCATION, Issue 1 2008Pablo Valdez ABSTRACT, Cognitive performance is affected by an individual's characteristics and the environment, as well as by the nature of the task and the amount of practice at it. Mental performance tests range in complexity and include subjective estimates of mood, simple objective tests (reaction time), and measures of complex performance that require decisions to be made and priorities set. Mental performance tasks show 2 components, a circadian rhythm and the effects of time awake. The circadian rhythm is in phase with the rhythm of core temperature and there is evidence for a causal link. Increasing time awake results in performance deterioration and is attributed to fatigue. The relative contribution of these 2 components depends upon the task under consideration; simple tasks generally show smaller effects due to increasing time awake. These contributions have been assessed by constant routines and forced desynchronization protocols and have formed the basis of several mathematical models that attempt to predict performance in a variety of field conditions. Mental performance is negatively affected by sleep loss; although short naps are beneficial, sleep inertia limits their value immediately after waking. The processes involved in cognition include attention (tonic and phasic alertness, and selective and sustained attention), working memory (phonological, used for speech, reading, and writing; and visuospatial, used for spatial processing, drawing, and mathematics), and executive function (initiative, decision making, and problem solving). These processes are illuminated by analysis of the regions of the brain involved, the presence of circadian rhythmicity, and the effects of sleep loss. The results from such laboratory- and field-based observations are relevant to the issue of learning in schoolchildren and lead to suggestions for improving their performance. [source] F plasmid partition depends on interaction of SopA with non-specific DNAMOLECULAR MICROBIOLOGY, Issue 4 2008Jean-Philippe Castaing Summary Bacterial ATPases belonging to the ParA family assure partition of their replicons by forming dynamic assemblies which move replicon copies into the new cell-halves. The mechanism underlying partition is not understood for the Walker-box ATPase class, which includes most plasmid and all chromosomal ParAs. The ATPases studied both polymerize and interact with non-specific DNA in an ATP-dependent manner. Previous work showed that in vitro, polymerization of one such ATPase, SopA of plasmid F, is inhibited by DNA, suggesting that interaction of SopA with the host nucleoid could regulate partition. In an attempt to identify amino acids in SopA that are needed for interaction with non-specific DNA, we have found that mutation of codon 340 (lysine to alanine) reduces ATP-dependent DNA binding > 100-fold and correspondingly diminishes SopA activities that depend on it: inhibition of polymer formation and persistence, stimulation of basal-level ATP hydrolysis and localization over the nucleoid. The K340A mutant retained all other SopA properties tested except plasmid stabilization; substitution of the mutant SopA for wild-type nearly abolished mini-F partition. The behaviour of this mutant indicates a causal link between interaction with the cell's non-specific DNA and promotion of the dynamic behaviour that ensures F plasmid partition. [source] Sensory functions in dystonia: Insights from behavioral studies,,MOVEMENT DISORDERS, Issue 10 2009Michele Tinazzi MD Abstract The pathophysiology of primary dystonia is thought to involve dysfunction of the basal ganglia cortico-striatal-thalamo-cortical motor circuits. In the past, emphasis was placed on the role of the basal ganglia in controlling movements; in more recent times, however, it has also become clear that they play an important part in sensory as well as cognitive functions. Here, we review evidence for dysfunction of sensory processing in patients with dystonia, and speculate that this may lead to abnormalities in a crucial role of the basal ganglia that links sensory information to appropriate motor output. Sensory function, particularly in the somatosensory domain, has been shown to be compromised in patients with primary dystonia, both in adult onset focal dystonia and in genetically characterized DYT1 dystonia. Given that nonaffected DYT1 gene carriers may show similar abnormalities to clinically affected individuals, sensory deficits could constitute a subclinical endophenotypic trait of disease that precedes overt clinical manifestations. Whether they can trigger primary dystonia or are an epiphenomenon is an issue warranting further study, but the fact that a number of different neurorehabilitative approaches explicitly manipulate somatosensory inputs to improve motor function suggests there may be a causal link between them. We believe that in future, randomized, blind and controlled studies in large patient populations should address this issue, providing efficient strategies to aid functional recovery, particularly in focal hand dystonia, where the available medical treatments offer little benefit. © 2009 Movement Disorder Society [source] Gadolinium and nephrogenic systemic fibrosis: Association or causation (Review Article)NEPHROLOGY, Issue 3 2008JAGADEESH KURTKOTI SUMMARY: With widespread availability of magnetic resonance imaging (MRI), it has become standard practice for patients with severe renal impairment or previous severe reactions to iodine-containing contrast media to receive gadolinium-based MRI contrast agents instead of traditional radiographic contrast agents, particularly for magnetic resonance angiography. However, there is growing concern about the use of gadolinium contrast agents in the presence of severe renal insufficiency, because of increasing reports of nephrogenic fibrosing dermopathy (NFD)/nephrogenic systemic fibrosis (NSF), associated with the exposure to certain gadolinium-containing contrast agents. In this review we explore the causal link between gadolinium exposure and NSF, using an established system of epidemiological criteria proposed by Bradford Hill. Though the current evidence makes gadolinium a strong suspect as an aetiologic agent for NSF in the presence of severe renal failure, the die is not cast yet. At this stage there needs to be cautious approach to the use of gadolinium-containing contrast agents in the presence of severe renal failure (glomerular filtration rate <30 mL/min per 1.73 m2). [source] Alpine flora dynamics , a critical review of responses to climate change in the Swedish Scandes since the early 1950sNORDIC JOURNAL OF BOTANY, Issue 4 2010Leif Kullman Reports about changes of alpine plant species richness over the past 60 years in the Swedish Scandes are reviewed, synthesized and updated with data from recent reinventories. Methodologically, this endeavour is based on resurveys of the floristic composition on the uppermost 20 m of four high-mountain summits. The key finding is that the species pool has increased by 60,170% since the 1950s and later. Some of the invading species are new to the alpine tundra, with more silvine and thermophilic properties than the extant alpine flora. Not a single species of the original flora has disappeared from any of the summits. This circumstance is discussed in perspective of widespread expectations of pending temperature-driven extinction of alpine species in an alleged future warmer climate. These progressive changes coincided with distinct warming (summer and winter) since the late 1980s. During a short cooler period (1974,1994), the species numbers decreased and the upper elevational limits of some ground cover species descended. Thus, discernible responses, concurrent with both warming and cooling intervals, sustain a strong causal link between climate variability and alpine plant species richness. Methodologically, plot-less revisitation studies of the present kind are beset with substantial uncertainties, which may overstate floristic changes over time. However, it is argued here that carefully executed and critically interpreted, no other method can equally effectively sense the earliest phases of plant invasions into alpine vegetation. [source] | ||||||||||||||||||||||||||||||||||||||||