729 research outputs found
Infrared catastrophe in two-quasiparticle collision integral
Relaxation of a non-equilibrium state in a disordered metal with a
spin-dependent electron energy distribution is considered. The collision
integral due to the electron-electron interaction is computed within the
approximation of a two-quasiparticle scattering. We show that the spin-flip
scattering processes with a small energy transfer may lead to the divergence of
the collision integral for a quasi one-dimensional wire. This divergence is
present only for a spin-dependent electron energy distribution which
corresponds to the total electron spin magnetization M=0 and only for non-zero
interaction in the triplet channel. In this case a non-perturbative treatment
of the electron-electron interaction is needed to provide an effective infrared
cut-off.Comment: 6 pages, 3 figure
Enhancement of Tc in the Superconductor-Insulator Phase Transition on Scale-Free Networks
A road map to understand the relation between the onset of the
superconducting state with the particular optimum heterogeneity in granular
superconductors is to study a Random Tranverse Ising Model on complex networks
with a scale-free degree distribution regularized by and exponential cutoff
p(k) \propto k^{-\gamma}\exp[-k/\xi]. In this paper we characterize in detail
the phase diagram of this model and its critical indices both on annealed and
quenched networks. To uncover the phase diagram of the model we use the tools
of heterogeneous mean-field calculations for the annealed networks and the most
advanced techniques of quantum cavity methods for the quenched networks. The
phase diagram of the dynamical process depends on the temperature T, the
coupling constant J and on the value of the branching ratio / where
k is the degree of the nodes in the network. For fixed value of the coupling
the critical temperature increases linearly with the branching ration which
diverges with the increasing cutoff value \xi or value of the \gamma exponent
\gamma< 3. This result suggests that the fractal disorder of the
superconducting material can be responsible for an enhancement of the
superconducting critical temperature. At low temperature and low couplings T<<1
and J<<1, instead, we observe a different behavior for annealed and quenched
networks. In the annealed networks there is no phase transition at zero
temperature while on quenched network we observe a Griffith phase dominated by
extremely rare events and a phase transition at zero temperature. The Griffiths
critical region, nevertheless, is decreasing in size with increasing value of
the cutoff \xi of the degree distribution for values of the \gamma exponents
\gamma< 3.Comment: (17 pages, 3 figures
Magnetically frustrated synthetic end member Mn2(PO4)OH in the triplite-triploidite family
The manganese end member of triplite-triploidite series of compounds, Mn2(PO4)OH, is synthesized by a hydrothermal method. Its crystal structure is refined in the space group P21/c with a = 12.411(1) Γ
, b = 13.323(1) Γ
, c = 10.014(1) Γ
, Ξ² = 108.16(1), V = 1573.3 Γ
3, Z = 8, and R = 0.0375. Evidenced in measurements of magnetization M and specific heat Cp, Mn2(PO4)OH reaches a long range antiferromagnetic order at TN = 4.6 K. As opposed to both triplite Mn2(PO4)F and triploidite-type Co2(PO4)F, the title compound is magnetically frustrated being characterized by the ratio of Curie-Weiss temperature Ξ to NΓ©el temperature TN of about 20. The large value of frustration strength Ξ/TN stems from the twisted saw tooth chain geometry of corner sharing triangles of Mn polyhedra, which may be isolated within tubular fragments of a triploidite crystal structure. Β© 2017 The Royal Society of Chemistry.We thank E. V. Guseva for the X-ray spectral analysis of the sample and N. V. Zubkova for her help in the X-ray experiment. This work was supported by the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST "MISiS" project K2-2016-066 and by RFBR projects 15-05-06742, 16-02-00021 and 17-02-00211. The work was supported by Act 211 Government of the Russian Federation, contracts 02.A03.21.0004, 02.A03.21.0006 and 02.A03.21.0011
Laser therapy in ROP: a literature review and our experience
Introduction: Retinopathy of prematurity (ROP) is a serious, vision threatening disease and among the leading causes of irreversible loss of vision. It affects prematurely born children, predominantly prior to the 32nd GW or with a body weight at birth below 1500 g. The highest risk for the development of ROP includes the time period of two weeks before to two weeks after the supposed due date. Materials and Methods: We included 10 prematurely born children with ROP requiring therapy. All of the children were screened by indirect ophthalmoscopy and the condition was documented by RetCam imaging. The treatment was conducted by the application of 810 nm diode laser. Results: Nine out of the 10 children were born before 32 GW and were with a body weight at birth below 1500 g. The disease was bilateral in 9 of the children. Laser therapy was applied to all 10 children and 18 eyes. Discussion and Conclusion: The active ophthalmological screening of all children born before 32 GW and with a body weight at birth below 1500 g, including all new-born children at risk, and the application of early laser treatment are the basis for the prevention of the development of irreversible visual loss
Pseudostrabismus, masking manifest strabismus
ΠΡΠ²Π΅Π΄Π΅Π½ΠΈΠ΅: Π§Π΅ΡΡΠΎ Π΄ΠΈΠ°Π³Π½ΠΎΠ·Π°ΡΠ° ΡΡΡΠ°Π±ΠΈΠ·ΡΠΌ Π΅ "ΠΈΠ·ΠΏΠΈΡΠ°Π½Π° Π½Π° Π»ΠΈΡΠ΅ΡΠΎ", ΠΎΡΠΎΠ±Π΅Π½ΠΎ ΠΏΡΠΈ Π³ΠΎΠ»ΡΠΌ ΡΠ³ΡΠ» Π½Π° ΠΎΡΠΊΠ»ΠΎΠ½Π΅Π½ΠΈΠ΅.ΠΡΠΏΡΠ΅ΠΊΠΈ ΡΠΎΠ²Π° Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΡΠ½Π°ΡΠ° Π΄ΠΈΠ»Π΅ΠΌΠ° Ρ ΡΠΈΡΠΊ ΠΎΡ Ρ
ΠΈΠΏΠ΅ΡΠ΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠ° Π΅ Π½Π°Π»ΠΈΡΠ΅, ΠΎΡΠΎΠ±Π΅Π½ΠΎ ΠΏΡΠΈ Π΄Π΅ΡΠ° Ρ Π΅ΠΏΠΈΠΊΠ°Π½ΡΡΡ, ΡΠ΅Π»Π΅ΠΊΠ°Π½ΡΡΡ, ΠΏΠΎΠ»ΠΎΠΆΠΈΡΠ΅Π»Π΅Π½ ΠΈΠ»ΠΈ ΠΎΡΡΠΈΡΠ°ΡΠ΅Π»Π΅Π½ ΡΠ³ΡΠ» ΠΊΠ°ΠΏΠ°. ΠΠ±ΡΠ°ΡΠ½ΠΎ, Π² Π½ΡΠΊΠΎΠΈ ΡΠ»ΡΡΠ°ΠΈ Π±Π΅Π· ΠΊΠΎΠ·ΠΌΠ΅ΡΠΈΡΠ΅Π½ Π²ΠΈΠ΄ Π½Π° ΠΊΡΠΈΠ²ΠΎΠ³Π»Π΅Π΄ΡΡΠ²ΠΎ, ΡΠ΅ ΡΡΡΠ°Π½ΠΎΠ²ΡΠ²Π° Π΄ΡΠ»Π±ΠΎΠΊΠΎ ΡΠ°Π·ΡΡΡΠΎΠΉΡΡΠ²ΠΎ Π½Π° Π±ΠΈΠ½ΠΎΠΊΡΠ»ΡΡΠ½ΠΎΡΠΎ Π·ΡΠ΅Π½ΠΈΠ΅ (Π°Π½ΠΎΡΠΌΠ°Π»Π½Π° ΡΠ΅ΡΠΈΠ½Π΅Π½Π° ΠΊΠΎΡΠ΅ΡΠΏΠΎΠ½Π΄Π΅Π½ΡΠΈΡ, Π°ΠΌΠ±Π»ΠΈΠΎΠΏΠΈΡ, ΡΠ΅Π½ΡΡΠ°Π»Π΅Π½ ΡΠΊΠΎΡΠΎΠΌ, ΡΠ΅Π΄ΡΡΠΈΡΠ°Π½Π° ΡΡΠ΅ΡΠ΅ΠΎ ΠΎΡΡΡΠΎΡΠ°) - ΠΌΠΈΠΊΡΠΎΡΡΡΠ°Π±ΠΈΠ·ΡΠΌ.ΠΡΠ΅Π²Π΄ΠΎΡΡΡΠ°Π±ΠΈΠ·ΠΌΡΡ ΠΌΠΎΠΆΠ΅ Π΄Π° ΡΡΡΠ΅ΡΡΠ²ΡΠ²Π° Π΅Π΄Π½ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎ Ρ ΠΈΡΡΠΈΠ½ΡΠΊΠΈ ΡΡΡΠ°Π±ΠΈΠ·ΡΠΌ, ΠΊΠ°ΡΠΎ ΠΊΠΎΠ·ΠΌΠ΅ΡΠΈΡΠ½ΠΎ Π³ΠΎ Π½Π΅ΡΡΡΠ°Π»ΠΈΠ·ΠΈΡΠ°, ΠΏΡΠ΅ΡΠ²Π΅Π»ΠΈΡΠ°Π²Π° ΠΈΠ»ΠΈ Π΄ΠΎΡΠΈ ΡΡΠ·Π΄Π°Π²Π° ΠΈΠ»ΡΠ·ΠΈΡ Π·Π° ΠΊΡΠΈΠ²Π΅Π½Π΅ Π² ΠΎΠ±ΡΠ°ΡΠ½Π° ΠΏΠΎΡΠΎΠΊΠ°.Π¦Π΅Π»: ΠΠ° ΠΏΠΎΠΊΠ°ΠΆΠ΅ΠΌ ΠΈΠ½ΡΠ΅ΡΠ΅ΡΠ½ΠΈ ΡΠ»ΡΡΠ°ΠΈ Ρ ΠΏΡΠ΅Π²Π΄ΠΎΡΡΡΠ°Π±ΠΈΠ·ΡΠΌ, ΡΡΡΠ΅ΡΡΠ²ΡΠ²Π°Ρ Π΅Π΄Π½ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎ Ρ ΠΈΡΡΠΈΠ½ΡΠΊΠΈ ΡΡΡΠ°Π±ΠΈΠ·ΡΠΌ.ΠΠ°ΡΠ΅ΡΠΈΠ°Π» ΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΈ: ΠΡΠ΅Π΄ΡΡΠ°Π²Π΅Π½ΠΈ ΡΠ° Π΄Π²Π° ΠΊΠ»ΠΈΠ½ΠΈΡΠ½ΠΈ ΡΠ»ΡΡΠ°ΠΈ Π½Π° Π΄Π΅ΡΠ° Ρ ΡΠ΅Π³ΡΠ΅ΡΠΈΡΠ°Π»Π° ΡΠΎΡΠΌΠ° Π½Π° ΡΠ΅ΡΠΈΠ½ΠΎΠΏΠ°ΡΠΈΡ Π½Π° Π½Π΅Π΄ΠΎΠ½ΠΎΡΠ΅Π½ΠΈΡΠ΅ (Π Π, ROP) ΠΈ ΠΏΠΎΠ»ΠΎΠΆΠΈΡΠ΅Π»Π΅Π½ ΡΠ³ΡΠ» ΠΊΠ°ΠΏΠ° Π² ΡΠ΅Π·ΡΠ»ΡΠ°Ρ ΠΎΡ Π΅ΠΊΡΠΎΠΏΠΈΡ Π½Π° ΠΌΠ°ΠΊΡΠ»Π°ΡΠ°. ΠΠ·ΠΏΠΎΠ»Π·Π²Π°Π½ΠΈ ΡΠ° ΠΎΡΡΠ°Π»ΠΌΠΎΠ»ΠΎΠ³ΠΈΡΠ½ΠΈ ΠΈ Π°ΡΡΠΎΠΏΡΠΈΡΠ½ΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΈ.Π Π΅Π·ΡΠ»ΡΠ°ΡΠΈ: Π Π΅Π΄ΠΈΠ½ΠΈΡ ΡΠ»ΡΡΠ°ΠΉ ΠΏΡΠ΅Π²Π΄ΠΎΠ΅ΠΊΠ·ΠΎΡΡΠΎΠΏΠΈΡΡΠ° ΠΊΠΎΠ·ΠΌΠ΅ΡΠΈΡΠ½ΠΎ ΠΊΠΎΠΌΠΏΠ΅Π½ΡΠΈΡΠ° Π½Π°ΠΏΡΠ»Π½ΠΎ ΡΡΡΠ΅ΡΡΠ²ΡΠ²Π°ΡΠ°ΡΠ° ΠΈΡΡΠΈΠ½ΡΠΊΠ° Π΅ΡΠΎΡΡΠΎΠΏΠΈΡ, a Π² Π΄ΡΡΠ³ΠΈΡ ΡΠ»ΡΡΠ°ΠΉ ΠΏΡΠΈ Π½Π°Π»ΠΈΡΠΈΠ΅ Π½Π° Π³ΠΎΠ»ΡΠΌ ΡΠ³ΡΠ» Π΅ΡΠΎΡΡΠΎΠΏΠΈΡ, ΠΊΠΎΠ·ΠΌΠ΅ΡΠΈΡΠ½ΠΈΡΡ Π²ΠΈΠ΄ Π΅ Π½Π° Π΅ΠΊΠ·ΠΎΡΡΠΎΠΏΠΈΡ.ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅: ΠΠ΅ΡΠ΅Π½ΡΡΠ°ΡΠΈΡΡΠ° Π½Π° ΠΊΠΎΡΠ½Π΅ΠΎ-ΡΠΎΠ²Π΅ΠΎΠ»Π°ΡΠ½ΠΈΡΡ ΡΠ΅ΡΠ»Π΅ΠΊΡ ΠΏΠΎ Π₯ΠΈΡΡΠ±Π΅ΡΠ³ Π½Π΅ Π΄ΠΎΠΊΠ°Π·Π²Π° ΡΡΡΠ°Π±ΠΈΠ·ΡΠΌ, Π½ΠΈΡΠΎ ΠΈΠ·ΠΌΠ΅ΡΠ²Π° ΡΠ³ΡΠ»Π° Π½Π° ΠΊΡΠΈΠ²Π΅Π½Π΅. ΠΠΈΠ°Π³Π½ΠΎΠ·Π°ΡΠ° Π·Π° ΠΈΡΡΠΈΠ½ΡΠΊΠ° Ρ
Π΅ΡΠ΅ΡΠΎΡΡΠΎΠΏΠΈΡ ΠΈΠ»ΠΈ Ρ
Π΅ΡΠ΅ΡΠΎΡΠΎΡΠΈΡ ΡΠ΅ ΠΏΠΎΡΡΠ°Π²Ρ ΡΠ»Π΅Π΄ cover/uncover ΡΠ΅ΡΡ. Π’Π°ΠΊΠ° ΠΌΠΎΠΆΠ΅ Π΄Π° ΡΠ΅ Π½Π°ΡΡΠΊΠ½Π΅ΠΌ Π½Π° ΡΡΡΠ΅ΡΡΠ²Π΅Π½ΠΈ ΡΠ°Π·Π»ΠΈΠΊΠΈ ΠΌΠ΅ΠΆΠ΄Ρ Π²ΠΈΠ΄ΠΈΠΌΠΎΡΠΎ ΠΈ ΠΈΡΡΠΈΠ½ΡΠΊΠΎ ΠΊΡΠΈΠ²Π΅Π½Π΅. ΠΡΠ°Π²ΠΈΠ»Π½Π°ΡΠ° Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠ° Π΅ Π²Π°ΠΆΠ½Π° Π·Π° ΠΏΡΠ°Π²ΠΈΠ»Π½ΠΎΡΠΎ ΠΎΡΡΠΎΠΏΡΠΈΡΠ½ΠΎ ΠΈ Ρ
ΠΈΡΡΡΠ³ΠΈΡΠ½Π° Π»Π΅ΡΠ΅Π½ΠΈΠ΅ Π½Π° ΡΡΡΠ°Π±ΠΈΠ·ΠΌΠ°.Introduction: The diagnosis strabismus is often "written on the face", especially in cases with large angle of deviation. Nevertheless, the diagnostic dilemma with a risk of hyperdiagnosis is present, especially in children with epicanthus, telecanthus, positive or negative kappa angle. Conversely, in some cases without a cosmetic appearance of squinting, there is a severe impairment of binocular vision (abnormal retinal correspondence, amblyopia, central scotoma, reduced stereo vision) - microstrabismus. Pseudostrabismus may coexist with real strabismus, cosmetically neutralizing it, exaggerating it or even creating an illusion of squinting in the opposite direction.Objective: To report interesting cases with pseudostrabismus, coexisting with real manifest strabismus.Material and Methods: We present two clinical cases of children with cicatricial retinopathy of prematurity (ROP) and positive angle kappa, resulting from ectopia of the macula. We use ophthalmic and ortoptic methods.Results: In one case the existing real esotropia is fully cosmetically compensated by pseudoexotropia. The other case has cosmetic appearance of exotropia, while a large angle of esotropic deviation is present on cover/uncover test.Conclusion: Decentration of the corneo-foveal reflex (Hirshberg) does not diagnose strabismus, nor it measures the angle of deviation. Diagnosis for real heterotropia or heterophoria is done only after cover/uncover test. Thus, we may encounter significant differences between visible and real squinting. Correct diagnosis of strabismus is important for the right ortoptic and surgical treatment
Helical vortex phase in the non-centrosymmetric CePt_3Si
We consider the role of magnetic fields on the broken inversion
superconductor CePt_3Si. We show that upper critical field for a field along
the c-axis exhibits a much weaker paramagnetic effect than for a field applied
perpendicular to the c-axis. The in-plane paramagnetic effect is strongly
reduced by the appearance of helical structure in the order parameter. We find
that to get good agreement between theory and recent experimental measurements
of H_{c2}, this helical structure is required. We propose a Josephson junction
experiment that can be used to detect this helical order. In particular, we
predict that Josephson current will exhibit a magnetic interference pattern for
a magnetic field applied perpendicular to the junction normal. We also discuss
unusual magnetic effects associated with the helical order.Comment: 5 pages, 2 figures, Accepted as Phys Rev. Lette
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