5,833 research outputs found
Numerical semigroups problem list
We propose a list of open problems in numerical semigroups.Comment: To appear in the CIM Bulletin, number 33. (http://www.cim.pt/) 13
page
Recommended from our members
Emotion processing in infancy: specificity in risk for social anxiety and associations with two year outcomes
The current study examined the specificity of patterns of responding to high and low intensity negative emotional expressions of infants of mothers with social phobia, and their association with child outcomes at two years of age. Infants of mothers with social phobia, generalised anxiety disorder (GAD) or no history of anxiety were shown pairs of angry and fearful emotional expressions at 10 weeks of age. Symptoms of social withdrawal, anxiety and sleep problems were assessed at two years of age. Only infants of mothers with social phobia showed a tendency to look away from high intensity fear faces; however infants of mothers with both social phobia and GAD showed a bias towards high intensity angry faces. Among the offspring of mothers with social phobia, anxiety symptoms at two years of age were associated with a preference for high intensity fear faces in infancy. The reverse pattern was found amongst the offspring of non-anxious mothers. These findings suggest a possible specific response to emotional expressions among the children of mothers with social phobia
Increased plasticity of the bodily self in eating disorders
Background: The rubber hand illusion (RHI) has been widely used to investigate the bodily self in healthy individuals. The aim of the present study was to extend the use of the RHI to examine the bodily self in eating disorders. Methods: The RHI and self-report measures of eating disorder psychopathology (EDI-3 subscales of Drive for Thinness, Bulimia, Body Dissatisfaction, Interoceptive Deficits, and Emotional Dysregulation; DASS-21; and the Self-Objectification Questionnaire) were administered to 78 individuals with an eating disorder and 61 healthy controls. Results: Individuals with an eating disorder experienced the RHI significantly more strongly than healthy controls on both perceptual (i.e., proprioceptive drift) and subjective (self-report questionnaire) measures. Furthermore, both the subjective experience of the RHI and associated proprioceptive biases were correlated with eating disorder psychopathology. Approximately 20% of the variance for embodiment of the fake hand was accounted for by eating disorder psychopathology, with interoceptive deficits and self-objectification significant predictors of embodiment. Conclusions: These results indicate that the bodily self is more plastic in people with an eating disorder. These findings may shed light on both aetiological and maintenance factors involved in eating disorders, particularly visual processing of the body, interoceptive deficits, and self-objectification
Is faunal diversity on Maltese sandy beaches related to intensity of human use?
Sandy beaches are rare in the Maltese Islands where only some 2.4% of the ca 271km coastline is
sedimentary; yet such beaches are much sought after for their amenity value by tourists and locals
alike. Carrying capacity studies conducted by the Malta tourism authorities have shown that most
beaches are under very heavy use while a study by Deidun et al. (2003) has indicated that the fauna of
Maltese sandy beaches tends to be impoverished compared to other Mediterranean beaches and has
hinted that this may be a result of lack of recruitment due to the relative isolation of these beaches.
Therefore human use of Maltese sandy beaches may potentially be a key factor affecting faunal
diversity of these beaches.
We explored this hypothesis by sampling the faunal assemblages of four Maltese beaches (Gnejna and
White Tower Bay on Malta, and Xatt l-Ahmar and Ramla l-Hamra on Gozo) using pitfall traps set up
in the wet and dry zones of each beach during the summer, when human use is expected to be highest.
Human use of these beaches was assessed by estimating human occupancy of the beaches from
standardised photographs. Beach occupancy values of 2400, 5700, 6700, and 12300 persons per square
km were estimated for Ramla, White Tower Bay, Xatt l-Ahmar and Gnejna, respectively, establishing a
gradient of anthropogenic impact with Gnejna as the most impacted beach and Ramla the least.
Three components of faunal diversity were considered: population size (number of individuals), species
richness, and taxonomic composition. Faunal population size ranged from 7 individuals/trap/hour for
Xatt l-Ahmar to 199 individuals/trap/hour for Ramla in the wet zone, and from 22 individuals/trap/hour
for White Tower Bay to 87.33 individuals/trap/hour for Gnejna in the dry zone. The species richness
ranged from 7 species (Xatt l-Ahmar) to 17 species (White Tower Bay). Between them, Amphipoda,
Isopoda, Coleoptera Dermaptera and Hymenoptera accounted for the bulk of both species and
individuals collected. There were no statistically significant correlations between population size,
species richness and taxonomic composition.
The species collected from the four beaches was categorized into psammophiles, coastal species
(occurring in coastal habitats but not restricted to sandy beaches) and euryoecious (ubiquitous) species.
Ramla exhibited the highest proportion of psammophiles (98.4% of all species collected at Ramla) and
the lowest proportion of ubiquitous ones (1.5% of all species), whilst for Xatt L-Ahmar the equivalent
figures were 31.8% and 61.8% for ubiquitous and psammophilic species respectively
From the present study it results that there is no trend between any of the three components of faunal
diversity analysed and the degree of human occupancy of the beaches, and the only tangible human
impact was related to faunal habitat–use specificity. This suggests that human use of the beaches has no
direct impact on the faunal assemblages of the mediolittoral and supralittoral zone of the beaches
studied but that high levels of human disturbance result in generalists displacing specialist
psammophilic species. In spite of these results, intense human use of Maltese sandy beaches is of conservation concern since
previous work has indicated a high degree of ‘compartmentalisation’ with different beaches harbouring
distinct faunal assemblages either due to natural inter-beach barriers to dispersal, or due to unique
environmental conditions present on the different beaches, including the nature and intensity of
anthropogenic pressures. In addition, the present study addresses only the direct effect of trampling by
beach visitors; indirect negative impacts, such as those of beach cleaning, have been well documented
in other studies.peer-reviewe
The impact of the Val158Met catechol-O-methyltransferase genotype on neural correlates of sad facial affect processing in patients with bipolar disorder and their relatives
Background - The Met allele of the catechol-O-methyltransferase (COMT) valine-to-methionine (Val158Met) polymorphism is known to affect dopamine-dependent affective regulation within amygdala-prefrontal cortical (PFC) networks. It is also thought to increase the risk of a number of disorders characterized by affective morbidity including bipolar disorder (BD), major depressive disorder (MDD) and anxiety disorders. The disease risk conferred is small, suggesting that this polymorphism represents a modifier locus. Therefore our aim was to investigate how the COMT Val158Met may contribute to phenotypic variation in clinical diagnosis using sad facial affect processing as a probe for its neural action. Method - We employed functional magnetic resonance imaging to measure activation in the amygdala, ventromedial PFC (vmPFC) and ventrolateral PFC (vlPFC) during sad facial affect processing in family members with BD (n=40), MDD and anxiety disorders (n=22) or no psychiatric diagnosis (n=25) and 50 healthy controls. Results - Irrespective of clinical phenotype, the Val158 allele was associated with greater amygdala activation and the Met allele with greater signal change in the vmPFC and vlPFC. Signal changes in the amygdala and vmPFC were not associated with disease expression. However, in the right vlPFC the Met158 allele was associated with greater activation in all family members with affective morbidity compared with relatives without a psychiatric diagnosis and healthy controls. Conclusions - Our results suggest that the COMT Val158Met polymorphism has a pleiotropic effect within the neural networks subserving emotional processing. Furthermore the Met158 allele further reduces cortical efficiency in the vlPFC in individuals with affective morbidity
A Clinical Investigation of Motivation to Change Standards and Cognitions about Failure in Perfectionism
Background: Clinical perfectionism is a transdiagnostic process that has been found to maintain eating disorders, anxiety disorders and depression. Cognitive behavioural models explaining the maintenance of clinical perfectionism emphasize the contribution of dichotomous thinking and resetting standards higher following both success and failure in meeting their goals. There has been a paucity of research examining the predictions of the models and motivation to change perfectionism. Motivation to change is important as individuals with clinical perfectionism often report many perceived benefits of their perfectionism; they are, therefore, likely to be ambivalent regarding changing perfectionism. Aims: The aim was to compare qualitative responses regarding questions about motivation to change standards and cognitions regarding failure to meet a personal standard in two contrasting groups with high and low negative perfectionism. Negative perfectionism refers to concern over not meeting personal standards. Method: A clinical group with a range of axis 1 diagnoses who were elevated on negative perfectionism were compared to a group of athletes who were low on negative perfectionism. Results: Results indicated that the clinical group perceived many negative consequences of their perfectionism. They also, however, reported numerous benefits and the majority stated that they would prefer not to change their perfectionism. The clinical group also reported dichotomous thinking and preferring to either keep standards the same or reset standards higher following failure, whilst the athlete group reported they would keep standards the same or set them lower. Conclusions: The findings support predictions of the cognitive behavioural model of clinical perfectionism
Evidence for Interlayer Electronic Coupling in Multilayer Epitaxial Graphene from Polarization Dependent Coherently Controlled Photocurrent Generation
Most experimental studies to date of multilayer epitaxial graphene on C-face
SiC have indicated that the electronic states of different layers are decoupled
as a consequence of rotational stacking. We have measured the third order
nonlinear tensor in epitaxial graphene as a novel approach to probe interlayer
electronic coupling, by studying THz emission from coherently controlled
photocurrents as a function of the optical pump and THz beam polarizations. We
find that the polarization dependence of the coherently controlled THz emission
expected from perfectly uncoupled layers, i.e. a single graphene sheet, is not
observed. We hypothesize that the observed angular dependence arises from weak
coupling between the layers; a model calculation of the angular dependence
treating the multilayer structure as a stack of independent bilayers with
variable interlayer coupling qualitatively reproduces the polarization
dependence, providing evidence for coupling.Comment: submitted to Nano Letter
- …