1,408 research outputs found
Independence of hyperlogarithms over function fields via algebraic combinatorics
We obtain a necessary and sufficient condition for the linear independence of
solutions of differential equations for hyperlogarithms. The key fact is that
the multiplier (i.e. the factor in the differential equation ) has
only singularities of first order (Fuchsian-type equations) and this implies
that they freely span a space which contains no primitive. We give direct
applications where we extend the property of linear independence to the largest
known ring of coefficients
A multipurpose Hopf deformation of the Algebra of Feynman-like Diagrams
We construct a three parameter deformation of the Hopf algebra
. This new algebra is a true Hopf deformation which reduces to
on one hand and to on the other, relating
to other Hopf algebras of interest in contemporary physics.
Further, its product law reproduces that of the algebra of polyzeta functions.Comment: 5 page
A Three Parameter Hopf Deformation of the Algebra of Feynman-like Diagrams
We construct a three-parameter deformation of the Hopf algebra \LDIAG. This
is the algebra that appears in an expansion in terms of Feynman-like diagrams
of the {\em product formula} in a simplified version of Quantum Field Theory.
This new algebra is a true Hopf deformation which reduces to \LDIAG for some
parameter values and to the algebra of Matrix Quasi-Symmetric Functions
(\MQS) for others, and thus relates \LDIAG to other Hopf algebras of
contemporary physics. Moreover, there is an onto linear mapping preserving
products from our algebra to the algebra of Euler-Zagier sums
Reproductive ecology of mangrove trees Ceriops decandra (Griff.) Ding Hou and Ceriops tagal (Perr.) C.B. Robinson (Rhizophoraceae)
Ceriops decandra and C. tagal are evergreen trees in the inner mangrove forests in Andhra Pradesh, India. Ceriops decandra is primarily a landward species whereas C. tagal is a seaward and highly salt tolerant species. Ceriops decandra produces flowers
and fruits continuously throughout the year while C. tagal produces flowers and fruits during winter only. Both species have amixed mating system with cross-pollination as the principal system and self-pollination, which is primarily vector-dependent. Ceriops
decandra flowers have a simple pollination mechanism that is adapted for pollination by daytime foragers, Nomia bees and Odynerus wasps. In contrast, C. tagal flowers have an elaborate and explosive pollination mechanism. Flies and honey bees trip the flowers and contribute to explosive pollen release and subsequent self- and cross-pollination.Wind is also effective in tripping the pollination mechanism but it largely contributes to self-pollination.
Bud abortion occurs only in C. decandra. Flower and fruit abortion occurs in both the species of Ceriops. Abortion at different stages of the reproductive unit has been considered to be a strategy by the plants to adjust the available maternal resources to the growing fruits and propagules. The paper provides the basis for further study for the conservation and management of Ceriops species in the study areas
Depression and PTSD Co-Morbidity: What are We Missing?
Background: Posttraumatic stress disorder (PTSD) and depression comorbidity is highly common. Many hypotheses concerning this relation have been raised but the pertinent issues, including the wide clinical picture of this comorbidity, are still not clear. The current study aims to bridge these gaps.
Method: We assessed PTSD, depression and comorbid indicators including dissociation, somatization, self- destructive behavior and suicidality among Israeli Yom Kippur war veterans at three time points (N = 349, 287, 301).
Results: Dissociation, somatization, self-destructive behavior and suicidality were predicted separately by group (PTSD, depression and comorbidity) and time of measurement using ANOVA and Chi squared analyses. The ‘comorbidity’ group expressed significantly higher dissociation, somatization, self-destructive behavior and suicidality, revealing high vulnerability of this group. Somatization presented a curvilinear-like development, increasing between T1 and T2 and slightly declining at T3, especially among the ‘comorbidity’ group. Suicidality showed a constant increase along the three measurements, especially among the comorbidity group.
Conclusions: A PTSD/depression comorbidity is both highly prevalent and long lasting and is often expressed concurrently with other related symptomatology, which causes further suffering and makes it more complicated for treatment. Implications for policy makers are briefly discussed
Current Practice Patterns Regarding the Conduct of Thyroidectomy and Parathyroidectomy amongst Surgeons - A Survey Study
Background: Heterogeneity of surgical care exists among surgeons regarding the conduct of thyroidectomy and parathyroidectomy
An interface between physics and number theory
We extend the Hopf algebra description of a simple quantum system given previously, to a more elaborate Hopf algebra, which is rich enough to encompass that related to a description of perturbative quantum field theory (pQFT). This provides a {\em mathematical} route from an algebraic description of non-relativistic, non-field theoretic quantum statistical mechanics to one of relativistic quantum field theory. Such a description necessarily involves treating the algebra of polyzeta functions, extensions of the Riemann Zeta function, since these occur naturally in pQFT. This provides a link between physics, algebra and number theory. As a by-product of this approach, we are led to indicate {\it inter alia} a basis for concluding that the Euler gamma constant may be rational
Endothelial dysfunction and carotid atherosclerosis in Malawian adults: A cross-sectional study
Background and objective
In sub-Saharan Africa, data on prevalence, risk factors and pathobiology of carotid atherosclerosis are scarce. We aimed to investigate the relationship between biomarkers of endothelial dysfunction and carotid atherosclerosis.
Methods
Carotid ultrasound was performed in 66 patients. Plasma concentration of ICAM-1, PAI-1, VEGF, and soluble thrombomodulin were measured by ELISA. A univariable logistic regression analysis was performed to study the relationship between carotid atherosclerosis, biomarkers of endothelial dysfunction, and various demographic and clinical parameters of the participants.
Results
The mean age of the participants was 58.7 years (95% CI: 54.4–63.1). Carotid atherosclerosis was diagnosed in 39.4% (95% CI: 27.6–52.2). In the univariable logistic regression, the following factors were associated with carotid atherosclerosis: age > 45 years (OR = 12.0, 95% CI: 1.4–98.8, p = .02), hypertension (OR = 3.8, 95% CI: 1.2–12.1, p = .02), and high-level of soluble thrombomodulin (OR = 3.4, 95% CI: 1.2–10.0, p = .02).
Conclusions
There is an association between high levels of soluble thrombomodulin and carotid atherosclerosis in Malawian adults. Further studies with a larger sample size are needed to confirm our findings in other African populations
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