70 research outputs found
Dissipation anomaly and energy cascade in 3D incompressible flows
The purpose of this note is to present a mathematical evidence of dissipation
anomaly in 3D turbulent flows within a general setting for the study of energy
cascade in physical scales of 3D incompressible flows recently introduced by
the authors.Comment: accepted to C. R. Math. Acad. Sci. Paris, final versio
Anomalous dissipation and energy cascade in 3D inviscid flows
Adopting the setting for the study of existence and scale locality of the
energy cascade in 3D viscous flows in physical space recently introduced by the
authors to 3D inviscid flows, it is shown that the anomalous dissipation is --
in the case of decaying turbulence -- indeed capable of triggering the cascade
which then continues ad infinitum, confirming Onsager's predictions.Comment: 14 pages, 1 figure, accepted to Comm. Math. Phy
Coherent vortex structures and 3D enstrophy cascade
Existence of 2D enstrophy cascade in a suitable mathematical setting, and
under suitable conditions compatible with 2D turbulence phenomenology, is known
both in the Fourier and in the physical scales. The goal of this paper is to
show that the same geometric condition preventing the formation of
singularities - 1/2-H\"older coherence of the vorticity direction - coupled
with a suitable condition on a modified Kraichnan scale, and under a certain
modulation assumption on evolution of the vorticity, leads to existence of 3D
enstrophy cascade in physical scales of the flow.Comment: 15 pp; final version -- to appear in CM
Management of the soft tissues of head and neck after dog bites at children
Department of Pediatric Surgery, Orthopedics and Anesthesiology
Nicolae Testemitanu State University of Medicine and Pharmacy, Chisinau, Republic of
Moldova, The 8th International Medical Congress for Students and Young Doctors, September 24-26, 2020Background. Even though the injuries of head and neck are mostly produced after car
accidents( in 80% of cases), dog bites which are 90% of all animal bites are frequent at children.
Bite wounds have always been considered complex injuries contaminated with unique
polymicrobial inoculum. Because wounds of the extremities constitute the majority of bite
cases, most relevant studies have focused on the wound infections rate in these areas. However,
a substantial subset of dog bites are located on the face, where fear of potential disfigurment is
a concern and the associated psychological consequences can be devastating.
(K,Stefanopoulos). 25% of the victims of dog bites are under age 6, and 34% are aged 6 to 17.
In small children, most bite wounds are on the head and neck; in older children and adolescents,
most are on the limbs. There have been estimated a total of 44,000 facial wounds due to dog
bites each year in the USA. In the Republic of Moldova there is also a significant number of
740 to 100,000 persons, which is three times less then the real number of dog bites wounds.
The injuries that result after these bites need a complex treatment and hospitalization. There is
a large range of lesions and infectious complications that can result after dog bites, therefore
studying the surgical methods and the complex pharmaceutical treatment is of a paramount
importance. The interdisciplinary management is recommended in dog bites inflected to the
head and neck at children. The antibiotic prophylaxis is used only in high risk of infection,
depending on the type, localization, animal species and patient characteristics. Many of bites
appear at children that are familiar to the dogs that attack them, therefore knowing the
epidemiology of them(scientific support, provocation, type of injury, risk factors)could help in spreading the information to parents, teachers and the general public to understand the behavior
of dogs over the vulnerable persons.
Case report. Patient X, male, 3 years. Diagnosis: Multiple injuries in the head and neck region
with tissue defect of 2/3 in the skin part of the head in occipital parietal front with cortical
exposure. Treatment: 1. Primary surgical treatment 2. Boring of cortical in the occipital parietal
front for stimulating the granulation tissue 3. Revision and extension of the wholes for
stimulating the granulation tissue 4. Grafting the granulated wounds of the head with split grafts
5. Excision of skin for grafting 6. Split skin grafts on small granulated zones 7. Excision of
skin for grafting 8. Wound dressing 9. Debridement of skin and subcutaneous tissue 10.
Treatment in resuscitation / intensive care the evolution of the disease with improvement. No
particularities. The patient's condition upon discharge is satisfactory. Internment date: 20th of
September 2019 Discharge date: 24th of November 2019
Conclusions. 1. Due to the small stature of the children up to 5 years, most of the injuries
resulting from the aggression of the dogs return to the level of the head and neck. The traumatic
lesions of the given region represent a surgical emergency due to the localization of organs
with vital functions such as the eyes, nose, mouth, ears, etc. but also to the aesthetic aspect of
the Maxillofacial region. 2. One of the most effective methods of restoring the massive defects
of the scalp after dog bites in children is the exposure of the diploid by multiple trepidation of
the scalp. After about 4 weeks the granulation tissue from the holes begins to cover the defect,
forming a favorable vascular bed for the skin grafts. 3. Dog bites management should include
measures to ensure wound care as close as possible to the accident. These actions should be
directed towards identifying and minimizing the risk of infection or other serious
complications. Surgical treatment includes general measures of local therapy, as well as antiinfectious
prophylaxis. Interdisciplinary collaboration is recommended to ensure the best
aesthetic and functional result. 4. Implementing prevention strategies (educating owners and
training dogs, monitoring threatening behavior and tackling future safety measures) can be
helpful in developing policy that can reduce this type of preventable trauma
Backward time behavior of dissipative PDE
We study behavior for negative times t of the 2D periodic Navier-Stokes equations
and Burgers' original model for turbulence. Both systems are proved to have
rich sets of solutions that exist for all t - R and increase exponentially as t -> -(Infinity) However, our study shows that the behavior of these solutions as well as the geometrical
structure of the sets of their initial data are very different. As a consequence,
Burgers original model for turbulence becomes the first known dissipative system that
despite possessing a rich set of backward-time exponentially growing solutions, does
not display any similarities, as t -> -(Infinity), to the linear case
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