30 research outputs found
Properties of C in the {\it ab initio} nuclear shell-model
We obtain properties of C in the {\it ab initio} no-core nuclear
shell-model. The effective Hamiltonians are derived microscopically from the
realistic CD-Bonn and the Argonne V8' nucleon-nucleon (NN) potentials as a
function of the finite harmonic oscillator basis space. Binding energies,
excitation spectra and electromagnetic properties are presented for model
spaces up to . The favorable comparison with available data is a
consequence of the underlying NN interaction rather than a phenomenological
fit.Comment: 9 pages, 2 figure
Giant optical anisotropy in transition metal dichalcogenides for next-generation photonics
Large optical anisotropy observed in a broad spectral range is of paramount
importance for efficient light manipulation in countless devices. Although a
giant anisotropy was recently observed in the mid-infrared wavelength range,
for visible and near-infrared spectral intervals, the problem remains acute
with the highest reported birefringence values of 0.8 in BaTiS3 and h-BN
crystals. This inspired an intensive search for giant optical anisotropy among
natural and artificial materials. Here, we demonstrate that layered transition
metal dichalcogenides (TMDCs) provide an answer to this quest owing to their
fundamental differences between intralayer strong covalent bonding and weak
interlayer van der Walls interaction. To do this, we carried out a correlative
far- and near-field characterization validated by first-principle calculations
that reveals an unprecedented birefringence of 1.5 in the infrared and 3 in the
visible light for MoS2. Our findings demonstrate that this outstanding
anisotropy allows for tackling the diffraction limit enabling an avenue for
on-chip next-generation photonics.Comment: 20 pages, 5 figure
The clinical case of limb-girdle muscle dystrophy 2Q associated with myasthenic syndrome and lung damage
Limb-girdle muscle dystrophy 2Q is one of the rarest forms of plectinopathies and is represented by an isolated muscular dystrophic syndrome, according to two previously described literature reports. There are five forms of plectinopathies, including limb-girdle muscle dystrophy 2Q, are caused by mutations in the PLEC gene, the alternative splicing of which determines the synthesis of 9 isoforms of the plectin protein (1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 3) performing cytolinker function in the neuronal, epithelial and muscle tissue.The article describes the family observation of three sick siblings with the limb-girdle muscle dystrophy 2Q phenotype due to the presence of a new homozygous mutation (NM_201378.3:c.58G>T, NP_958780.1:p.Glu20Ter) in the isoform 1f PLEC revealed by whole-exome sequencing. Clinical, electromyography, visualization and histopathological features of limb-girdle muscle dystrophy 2Q were analyzed in detail. The onset of clinical manifestations in all the described siblings was observed in early childhood with moderate weakness mainly in the pelvic girdle muscles and proximal lower limbs with minimal involvement of the muscles of the shoulder girdle. A distinctive aspect is the stagnation of the myodystrophic process until 20—21 years, followed by the progression and development of episodes of respiratory failure, as well as the formation of rigidity of the cervical, thoracic spine and moderate contracture of the Achilles tendons. Typical features are marked atrophy of paravertebral muscles with the formation of pterygoid scapula and the presence of hypertrophy m. gastrocnemius, m. quadriceps femoris, m. deltoideus and m. triceps brachii. Histopathological examination m. vastus lateralis revealed myodystrophic process without inflammatory infiltration, muscle fiber cytoskeleton disorganization resulted from the plectin loss.Electrocardiography signs of the early repolarization syndrome, focal cardiosclerosis and sinus tachycardia are described. For the first time, involvement in the pathological process of pulmonary tissue in the form of noninfectious bronchiolitis, atelectasis, and the development of the myasthenic syndrome causing episodes of respiratory failure resulted in the death of two described siblings aged 29 and 31 years. Discussed pathogenetic role of PLEC 1f isoform in the development of described syndromes, expands understanding of rare nosology limb-girdle muscle dystrophy 2Q
Three-Nucleon Forces from Chiral Effective Field Theory
We perform the first complete analysis of nd scattering at
next-to-next-to-leading order in chiral effective field theory including the
corresponding three-nucleon force and extending our previous work, where only
the two-nucleon interaction has been taken into account. The three-nucleon
force appears first at this order in the chiral expansion and depends on two
unknown parameters. These two parameters are determined from the triton binding
energy and the nd doublet scattering length. We find an improved description of
various scattering observables in relation to the next-to-leading order results
especially at moderate energies (E_lab = 65 MeV). It is demonstrated that the
long-standing A_y-problem in nd elastic scattering is still not solved by the
leading 3NF, although some visible improvement is observed. We discuss
possibilities of solving this puzzle. The predicted binding energy for the
alpha-particle agrees with the empirical value.Comment: 36 pp, 20 figure
The Hyperspherical Four-Fermion Problem
The problem of a few interacting fermions in quantum physics has sparked
intense interest, particularly in recent years owing to connections with the
behavior of superconductors, fermionic superfluids, and finite nuclei. This
review addresses recent developments in the theoretical description of four
fermions having finite-range interactions, stressing insights that have emerged
from a hyperspherical coordinate perspective. The subject is complicated, so we
have included many detailed formulas that will hopefully make these methods
accessible to others interested in using them. The universality regime, where
the dominant length scale in the problem is the two-body scattering length, is
particularly stressed, including its implications for the famous BCS-BEC
crossover problem Derivations and relevant formulas are also included for the
calculation of challenging few-body processes such as recombination.Comment: 66 pages, 33 figure
Клинический случай поясно-конечностной мышечной дистрофии 2Q, ассоциированной с миастеническим синдромом и поражением легких
Limb-girdle muscle dystrophy 2Q is one of the rarest forms of plectinopathies and is represented by an isolated muscular dystrophic syndrome, according to two previously described literature reports. There are five forms of plectinopathies, including limb-girdle muscle dystrophy 2Q, are caused by mutations in the PLEC gene, the alternative splicing of which determines the synthesis of 9 isoforms of the plectin protein (1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 3) performing cytolinker function in the neuronal, epithelial and muscle tissue.The article describes the family observation of three sick siblings with the limb-girdle muscle dystrophy 2Q phenotype due to the presence of a new homozygous mutation (NM_201378.3:c.58G>T, NP_958780.1:p.Glu20Ter) in the isoform 1f PLEC revealed by whole-exome sequencing. Clinical, electromyography, visualization and histopathological features of limb-girdle muscle dystrophy 2Q were analyzed in detail. The onset of clinical manifestations in all the described siblings was observed in early childhood with moderate weakness mainly in the pelvic girdle muscles and proximal lower limbs with minimal involvement of the muscles of the shoulder girdle. A distinctive aspect is the stagnation of the myodystrophic process until 20—21 years, followed by the progression and development of episodes of respiratory failure, as well as the formation of rigidity of the cervical, thoracic spine and moderate contracture of the Achilles tendons. Typical features are marked atrophy of paravertebral muscles with the formation of pterygoid scapula and the presence of hypertrophy m. gastrocnemius, m. quadriceps femoris, m. deltoideus and m. triceps brachii. Histopathological examination m. vastus lateralis revealed myodystrophic process without inflammatory infiltration, muscle fiber cytoskeleton disorganization resulted from the plectin loss.Electrocardiography signs of the early repolarization syndrome, focal cardiosclerosis and sinus tachycardia are described. For the first time, involvement in the pathological process of pulmonary tissue in the form of noninfectious bronchiolitis, atelectasis, and the development of the myasthenic syndrome causing episodes of respiratory failure resulted in the death of two described siblings aged 29 and 31 years. Discussed pathogenetic role of PLEC 1f isoform in the development of described syndromes, expands understanding of rare nosology limb-girdle muscle dystrophy 2Q.Поясно-конечностная мышечная дистрофия 2Q является одной из наиболее редких форм плектинопатий и проявляется изолированным мышечным дистрофическим синдромом согласно двум ранее представленным в литературе описаниям. Пять существующих форм плектинопатий, в том числе поясно-конечностная мышечная дистрофия 2Q, обусловлены мутациями в гене PLEC, альтернативный сплайсинг которого определяет синтез 9 изоформ белка плектина (1, 1а, 1b, 1c, 1d, 1е, 1f,1g, 3), выполняющих цитолинкерную функцию в нейрональной, эпителиальной и мышечной тканях.В статье представлено описание семейного наблюдения 3 больных сибсов с поясно-конечностной мышечной дистрофией 2Q, обусловленного наличием новой гомозиготной мутации (NM_201378.3:c.58G>T, NP_958780.1:p.Glu20Ter) в изоформе 1f гена PLEC, выявленной с помощью полноэкзомного секвенирования. Детально проанализированы клинические, электронейромиографические, визуализационные и патогистологические особенности поясно-конечностной мышечной дистрофии 2Q. Дебют клинических проявлений у всех описанных членов семьи наблюдался в раннем детском возрасте в виде умеренной слабости преимущественно мышц тазового пояса и проксимальных отделов ног с минимальным вовлечением мышц плечевого пояса. Отличительным аспектом является стагнация миодистрофического процесса до 20—21 года с последующим прогрессированием и развитием эпизодов дыхательной недостаточности, а также формированием ригидности шейного, грудного отдела позвоночника и умеренной контрактуры ахилловых сухожилий. Характерными являются выраженная атрофия mm. paravertebralis с формированием крыловидных лопаток и наличие гипертрофии m. gastrocnemius, m. quadriceps femoris, m. deltoideus и m. triceps brachii. Патогистологическое исследование m. vastus lateralis отражает наличие миодистрофического процесса без воспалительной инфильтрации, дезорганизацию цитоскелета мышечных волокон и утрату плектина. Описаны электрокардиографические признаки синдрома ранней реполяризации, очагового кардиосклероза и синусовой тахикардии. Впервые в литературе представлено сочетание пояс-но-конечностной мышечной дистрофии 2Q с поражением легких в виде неинфекционного бронхиолита, ателектазов и развитием миастенического синдрома, обусловливающими эпизоды дыхательной недостаточности и повлекшие смерть 2 описываемых сибсов в возрасте 29 и 31 года. Обсуждаемое патогенетическое значение 1f-изоформы плектина в развитии описанных синдромов позволяет расширить представление о редкой нозологии — поясно-конечностной мышечной дистрофии 2Q
Relativistic five-quark equations and hybrid baryon spectroscopy
The relativistic five-quark equations are found in the framework of the
dispersion relation technique. The behavior of the low-energy five-particle
amplitude is determined by its leading singularities in the pair invariant
masses. The solutions of these equations using the method based on the
extraction leading singularities of the amplitudes are obtained. The mass
spectra of nucleon and delta-isobar hybrid baryons are calculated. The
calculations of hybrid baryon amplitudes estimate the contributions of four
subamplitudes. The main contributions to the hybrid baryon amplitude are
determined by the subamplitudes, which include the excited gluon states.Comment: 22 pages, pdf, minor changes in text and reference
The problems of creating a propulsion system of a new generation supersonic passenger aircraft (review)
The problems of creating a propulsion system for a new generation supersonic passenger aircraft are considered on the basis of a review of the work on the supersonic transport being carried out in the world. It is shown that the desire to achieve high flight performance and commercial effectiveness of a supersonic passenger aircraft while meeting up-to-date environmental requirements leads to contradictory technical solutions regarding the propulsion system: the location and number of engines, the scheme of the air intake and nozzle, the choice of the scheme and design parameters of the engine, the use of new high-temperature materials in the engine hot section, etc. The features of the operating conditions of the engine components of a supersonic passenger aircraft in comparison with the engines of up-to-date subsonic civil aviation aircraft and supersonic military aircraft are indicated. The calculated estimates of the influence of various technical solutions on the parameters of the supersonic passenger aircraft engine are given. Due to the complexity and multi-criterion nature of the task of creating a supersonic passenger aircraft propulsion system, its solution requires an integrated approach based on close cooperation of specialists in airframe aerodynamics, engine, etc