251 research outputs found
On the equivalence between hierarchical segmentations and ultrametric watersheds
We study hierarchical segmentation in the framework of edge-weighted graphs.
We define ultrametric watersheds as topological watersheds null on the minima.
We prove that there exists a bijection between the set of ultrametric
watersheds and the set of hierarchical segmentations. We end this paper by
showing how to use the proposed framework in practice in the example of
constrained connectivity; in particular it allows to compute such a hierarchy
following a classical watershed-based morphological scheme, which provides an
efficient algorithm to compute the whole hierarchy.Comment: 19 pages, double-colum
On morphological hierarchical representations for image processing and spatial data clustering
Hierarchical data representations in the context of classi cation and data
clustering were put forward during the fties. Recently, hierarchical image
representations have gained renewed interest for segmentation purposes. In this
paper, we briefly survey fundamental results on hierarchical clustering and
then detail recent paradigms developed for the hierarchical representation of
images in the framework of mathematical morphology: constrained connectivity
and ultrametric watersheds. Constrained connectivity can be viewed as a way to
constrain an initial hierarchy in such a way that a set of desired constraints
are satis ed. The framework of ultrametric watersheds provides a generic scheme
for computing any hierarchical connected clustering, in particular when such a
hierarchy is constrained. The suitability of this framework for solving
practical problems is illustrated with applications in remote sensing
Freeze-out configuration properties in the 197Au + 197Au reaction at 23 AMeV
Data from the experiment on the 197Au + 197Au reaction at 23 AMeV are
analyzed with an aim to find signatures of exotic nuclear configurations such
as toroid-shaped objects. The experimental data are compared with predictions
of the ETNA code dedicated to look for such configurations and with the QMD
model. A novel criterion of selecting events possibly resulting from the
formation of exotic freeze-out configurations, "the efficiency factor", is
tested. Comparison between experimental data and model predictions may indicate
for the formation of flat/toroidal nuclear systems
Scattering theory for Klein-Gordon equations with non-positive energy
We study the scattering theory for charged Klein-Gordon equations:
\{{array}{l} (\p_{t}- \i v(x))^{2}\phi(t,x) \epsilon^{2}(x,
D_{x})\phi(t,x)=0,[2mm] \phi(0, x)= f_{0}, [2mm] \i^{-1} \p_{t}\phi(0, x)=
f_{1}, {array}. where: \epsilon^{2}(x, D_{x})= \sum_{1\leq j, k\leq
n}(\p_{x_{j}} \i b_{j}(x))A^{jk}(x)(\p_{x_{k}} \i b_{k}(x))+ m^{2}(x),
describing a Klein-Gordon field minimally coupled to an external
electromagnetic field described by the electric potential and magnetic
potential . The flow of the Klein-Gordon equation preserves the
energy: h[f, f]:= \int_{\rr^{n}}\bar{f}_{1}(x) f_{1}(x)+
\bar{f}_{0}(x)\epsilon^{2}(x, D_{x})f_{0}(x) - \bar{f}_{0}(x) v^{2}(x) f_{0}(x)
\d x. We consider the situation when the energy is not positive. In this
case the flow cannot be written as a unitary group on a Hilbert space, and the
Klein-Gordon equation may have complex eigenfrequencies. Using the theory of
definitizable operators on Krein spaces and time-dependent methods, we prove
the existence and completeness of wave operators, both in the short- and
long-range cases. The range of the wave operators are characterized in terms of
the spectral theory of the generator, as in the usual Hilbert space case
Parental supply of alcohol and alcohol consumption in adolescence: prospective cohort study
Background: Parents are a major supplier of alcohol to adolescents, yet there is limited research examining the impact of this on adolescent alcohol use. This study investigates associations between parental supply of alcohol, supply from other sources, and adolescent drinking, adjusting for child, parent, family and peer variables. Method: A cohort of 1927 adolescents was surveyed annually from 2010 to 2014. Measures include: consumption of whole drinks; binge drinking (>4 standard drinks on any occasion); parental supply of alcohol; supply from other sources; child, parent, family and peer covariates. Results: After adjustment, adolescents supplied alcohol by parents had higher odds of drinking whole beverages [odds ratio (OR) 1.80, 95% confidence interval (CI) 1.33–2.45] than those not supplied by parents. However, parental supply was not associated with bingeing, and those supplied alcohol by parents typically consumed fewer drinks per occasion (incidence rate ratio 0.86, 95% CI 0.77–0.96) than adolescents supplied only from other sources. Adolescents obtaining alcohol from non-parental sources had increased odds of drinking whole beverages (OR 2.53, 95% CI 1.86–3.45) and bingeing (OR 3.51, 95% CI 2.53–4.87). Conclusions: Parental supply of alcohol to adolescents was associated with increased risk of drinking, but not bingeing. These parentally-supplied children also consumed fewer drinks on a typical drinking occasion. Adolescents supplied alcohol from non-parental sources had greater odds of drinking and bingeing. Further follow-up is necessary to determine whether these patterns continue, and to examine alcohol-related harm trajectories. Parents should be advised that supply of alcohol may increase children's drinking
A Mother's Attitude Towards Her Infant and Child Behaviour Five Years Later
Objective The relationship between maternal attitude to the infant at 6 months of age and behavioural outcomes at 5 years is explored, controlling for numerous demographic, child and psychosocial family factors. Method Data was used from the Mater-University Study of Pregnancy, an Australian longitudinal study of over 7000 mothers and children followed from pregnancy to when the children were 5 years. Measures ranging from the key variables of maternal attitude and child behaviour as well as numerous confounders were dichotomised. Logistic regression analyses were performed to examine the relationship between maternal negative attitude toward the infant and clinically significant levels of child behaviour problems and other infant risks, early social risks, and concurrent social risks. Results The results suggest that maternal negative attitude towards the infant at 6 months is an independent predictor of child behaviour problems at 5 years. This association remained significant for boys' externalizing behaviours and girls' internalizing behaviours. Conclusions The findings lend support to the concept of a sensitive period in early infancy; the need for a broad perspective in the assessment of the mother-infant relationship and the need for early intervention with dysfunctional mother-infant dyads
Low-temperature thermochronology of the Indus Basin in central Ladakh, northwest India: implications of Miocene–Pliocene cooling in the India-Asia collision zone
The India‐Asia collision zone in Ladakh, northwest India, records a sequence of tectono‐thermal events in the interior of the Himalayan orogen following the intercontinental collision between India and Asia in early Cenozoic time. We present zircon fission‐track, and zircon and apatite (U‐Th)/He thermochronometric data from the Indus Basin sedimentary rocks that are exposed along the strike of the collision zone in central Ladakh. These data reveal a post‐depositional Miocene–Pliocene (~22–4 Ma) cooling signal along the India‐Asia collision zone in northwest India. Our ZFT cooling ages indicate that maximum basin temperatures exceeded 200 °C but stayed below 280–300 °C in the stratigraphically deeper marine and continental strata. Thermal modeling of zircon and apatite (U‐Th)/He cooling ages suggests post‐depositional basin cooling initiated in Early Miocene time by ~22–20 Ma, occurred throughout the basin across zircon (U‐Th)/He partial retention temperatures from ~20–10 Ma, and continued in the Pliocene time until at least ~4 Ma. We attribute the burial of the Indus Basin to sedimentation and movement along the regional Great Counter thrust. The ensuing Miocene–Pliocene cooling resulted from erosion by the Indus River that transects the basin. An approximately coeval cooling signal is well documented east of the study area, along the collision zone in south Tibet. Our new data provide a regional framework upon which future studies can explore the possible interrelationships between tectonic, geodynamic and geomorphologic factors contributing to Miocene–Pliocene cooling along the India‐Asia collision zone from NW India to south Tibet
Change in maternal body mass index is associated with offspring body mass index: a 21-year prospective study
High body-mass index (BMI; defined as 25 kg/m(2) or greater) is associated with increased risk of cancer. To inform public health policy and future research, we estimated the global burden of cancer attributable to high BMI in 2012
Income differences in food consumption in the 1995 Australian national nutrition survey
Objective: To assess the relationships between an index of per capita income and the intake of a variety of individual foods as well as groups of food for men and women in different age groups. Design: Cross-sectional national survey of free-living men and women. Subjects: A sample of 5053 males and 5701 females aged 18 y and over who completed the Australian National Nutrition Survey 1995. Methods: Information about the frequency of consumption of 88 food items was obtained. On the basis of scores on the Food Frequency Questionnaire, regular and irregular consumers of single foods were identified. The relationships between regularity of consumption of individual foods and per capita income were analysed via contingency tables. Food variety scores were derived by assigning individual foods to conventional food group taxonomies, and then summing up the dichotomised intake scores for individual foods within each food group. Two-way ANOVA (income age group) were performed on the food variety scores for males and females, respectively. Results: Per capita income was extensively related to the reported consumption of individual foods and to total and food group variety indices. Generally, both men and women in low income households had less varied diets than those in higher-income households. However, several traditional foods were consumed less often by young high-income respondents, especially young women. Conclusions: Major income differentials in food variety occur in Australia but they are moderated by age and gender. Younger high-income women, in particular, appear to have rejected a number of traditional foods, possibly on the basis of health beliefs. The findings also suggest that data aggregation has marked effects on income and food consumption relationships.<br /
How Mistimed and Unwanted Pregnancies Affect Timing of Antenatal Care Initiation in three Districts in Tanzania
Early antenatal care (ANC) initiation is a doorway to early detection and management of potential complications associated with pregnancy. Although the literature reports various factors associated with ANC initiation such as parity and age, pregnancy intentions is yet to be recognized as a possible predictor of timing of ANC initiation. Data originate from a cross-sectional household survey on health behaviour and service utilization patterns. The survey was conducted in 2011 in Rufiji, Kilombero and Ulanga districts in Tanzania on 910 women of reproductive age who had given birth in the past two years. ANC initiation was considered to be early only if it occurred in the first trimester of pregnancy gestation. A recently completed pregnancy was defined as mistimed if a woman wanted it later, and if she did not want it at all the pregnancy was termed as unwanted. Chisquare was used to test for associations and multinomial logistic regression was conducted to examine how mistimed and unwanted pregnancies affect timing of ANC initiation. Although 49.3% of the women intended to become pregnant, 50.7% (34.9% mistimed and 15.8% unwanted) became pregnant unintentionally. While ANC initiation in the 1st trimester was 18.5%, so was 71.7% and 9.9% in the 2nd and 3rd trimesters respectively. Multivariate analysis revealed that ANC initiation in the 2nd trimester was 1.68 (95% CI 1.10‒2.58) and 2.00 (95% CI 1.05‒3.82) times more likely for mistimed and unwanted pregnancies respectively compared to intended pregnancies. These estimates rose to 2.81 (95% CI 1.41‒5.59) and 4.10 (95% CI 1.68‒10.00) respectively in the 3rd trimester. We controlled for gravidity, age, education, household wealth, marital status, religion, district of residence and travel time to a health facility. Late ANC initiation is a significant maternal and child health consequence of mistimed and unwanted pregnancies in Tanzania. Women should be empowered to delay or avoid pregnancies whenever they need to do so. Appropriate counseling to women, especially those who happen to conceive unintentionally is needed to minimize the possibility of delaying ANC initiation.\u
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