1,746 research outputs found
Rotating solenoidal perfect fluids of Petrov type D
We prove that aligned Petrov type D perfect fluids for which the vorticity
vector is not orthogonal to the plane of repeated principal null directions and
for which the magnetic part of the Weyl tensor with respect to the fluid
velocity has vanishing divergence, are necessarily purely electric or locally
rotationally symmetric. The LRS metrics are presented explicitly.Comment: 6 pages, no figure
Purely radiative irrotational dust spacetimes
We consider irrotational dust spacetimes in the full non-linear regime which
are "purely radiative" in the sense that the gravitational field satisfies the
covariant transverse conditions div(H) = div(E) = 0. Within this family we show
that the Bianchi class A spatially homogeneous dust models are uniquely
characterised by the condition that is diagonal in the shear-eigenframe.Comment: 6 pages, ERE 2006 conference, minor correction
Purely radiative perfect fluids
We study `purely radiative' (div E = div H = 0) and geodesic perfect fluids
with non-constant pressure and show that the Bianchi class A perfect fluids can
be uniquely characterized --modulo the class of purely electric and
(pseudo-)spherically symmetric universes-- as those models for which the
magnetic and electric part of the Weyl tensor and the shear are simultaneously
diagonalizable. For the case of constant pressure the same conclusion holds
provided one also assumes that the fluid is irrotational.Comment: 12 pages, minor grammatical change
Shearfree perfect fluids with solenoidal magnetic curvature and a gamma-law equation of state
We show that shearfree perfect fluids obeying an equation of state p=(gamma
-1) mu are non-rotating or non-expanding under the assumption that the spatial
divergence of the magnetic part of the Weyl tensor is zero.Comment: 11 page
Complete invasion of <i>Impatiens glandulifera</i> in the Scheldt basin - prospects for 'hydrological control'
Symptoms and functional status of patients with disseminated cancer visiting outpatient departments
Considerable research has focused on pain and other symptoms in terminal cancer patients referred to hospices and palliative care services. These patients differ from Dutch cancer patients in the palliative stage of their disease because the latter are cared for by general practitioners at home and medical specialists in outpatient departments. To clarify the experience of these Dutch patients, a study was started to investigate the prevalence and severity of pain and other symptoms as well as the functional status of consecutive patients visiting oncology outpatient departments for follow-up. After randomization, one group (I) of patients was interviewed at home by a general practitioner using structured questionnaires. The other group (II) received the questionnaires by mail, and scored the symptoms independently. The results of the symptom assessment show that patients in groups I and II suffered 2.4 (SD = 1.7) and 2.8 (SD = 2.0) symptoms, respectively. Between 30% and 40% of all patients reported constipation, nausea, loss of appetite, coughing, and dyspnea. These percentages were 50% lower when only moderate, severe, or extremely distressing symptoms were included. Sixty percent of all patients had pain, and 20% indicated a daytime pain score of 5 or greater on a scale of 0 to 10. Functional status was measured by the COOPWONCA charts; the mean score for the charts "physical fitness" and "daily activities" was 1.5 points lower for cancer patients than a random sample from the community of the same age and gender. The findings of this study should motivate doctors to put more energy in symptom assessment and interventions in palliative care. Record 29 of 32 - SilverPlatter MEDLINE(R)
Does mindful parenting mediate the association between maternal anxiety during pregnancy and child behavioral/emotional problems?
Objectives Maternal anxiety during pregnancy is a risk factor for child behavioral/emotional problems. Knowledge about explanatory factors mediating this link is scarce. Maternal anxiety during pregnancy may be an indicator of adverse postnatal environmental conditions, including maternal anxiety and poor parenting, possibly affecting child behavior. This study investigated whether maternal anxiety and mindful parenting in early childhood mediate the association between maternal anxiety during pregnancy and child behavioral/emotional problems. Methods This study was based on a sample of 118 mother-child dyads who participated in a cohort study that followed participants from pregnancy until 4 years after birth. At 21 weeks’ gestation and when the child was 4 years old, mothers completed questionnaires to assess state anxiety (State-Trait Anxiety Inventory) and general anxiety (Symptom Checklist-90 anxiety subscale). At age 4 years, mothers reported mindful parenting (Interpersonal Mindfulness in Parenting Scale) and child behavioral/emotional problems (Child Behavior Checklist). Results Maternal state anxiety during pregnancy was positively associated with child internalizing problems and negatively with mindful parenting. Maternal general anxiety during pregnancy was related with more child internalizing and externalizing problems but not with mindful parenting. The association between maternal state anxiety during pregnancy and child internalizing problems was sequentially mediated via concurrent maternal general anxiety and mindful parenting. Conclusions These findings suggest that maternal anxiety during pregnancy continues into early childhood and, because of this, it subsequently affects child internalizing behavior via poor mindful parenting. Replication studies are needed before developing interventions for tackling maternal anxiety during pregnancy and promoting mindful parenting
Non-commutative desingularization of determinantal varieties, I
We show that determinantal varieties defined by maximal minors of a generic
matrix have a non-commutative desingularization, in that we construct a maximal
Cohen-Macaulay module over such a variety whose endomorphism ring is
Cohen-Macaulay and has finite global dimension. In the case of the determinant
of a square matrix, this gives a non-commutative crepant resolution.Comment: 52 pages, 3 figures, all comments welcom
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