Velocity, energy and helicity of vortex knots and unknots

In this paper we determine the velocity, the energy and estimate writhe and twist helicity contributions of vortex filaments in the shape of torus knots and unknots (toroidal and poloidal coils) in a perfect fluid. Calculations are performed by numerical integration of the Biot-Savart law. Vortex complexity is parametrized by the winding number $w$, given by the ratio of the number of meridian wraps to that of the longitudinal wraps. We find that for $w<1$ vortex knots and toroidal coils move faster and carry more energy than a reference vortex ring of same size and circulation, whereas for $w>1$ knots and poloidal coils have approximately same speed and energy of the reference vortex ring. Helicity is dominated by the writhe contribution. Finally, we confirm the stabilizing effect of the Biot-Savart law for all knots and unknots tested, that are found to be structurally stable over a distance of several diameters. Our results also apply to quantized vortices in superfluid $^4$He.Comment: 17 pages, 8 figures, 2 table

Kelvin Wave Cascade and Decay of Superfluid Turbulence

Kelvin waves (kelvons)--the distortion waves on vortex lines--play a key part in the relaxation of superfluid turbulence at low temperatures. We present a weak-turbulence theory of kelvons. We show that non-trivial kinetics arises only beyond the local-induction approximation and is governed by three-kelvon collisions; corresponding kinetic equation is derived. On the basis of the kinetic equation, we prove the existence of Kolmogorov cascade and find its spectrum. The qualitative analysis is corroborated by numeric study of the kinetic equation. The application of the results to the theory of superfluid turbulence is discussed.Comment: 4 pages, RevTe

Perbedaan Kompetensi Sosial Anak Berdasarkan Tipe Pendidikan Prasekolah

Penelitian ini bertujuan untuk mengetahui peran tipe pendidikan prasekolah dalam kompetensi sosial anak. Dua hipotesis diajukan untuk menguji perbedaan kompetensi sosial anak dengan tipe pendidikan prasekolah penuh waktu dan paruh waktu. Subjek penelitian ini adalah 209 orang anak usia lima sampai dengan enam tahun yang mengikuti salah satu tipe pendidikan prasekolah (paruh waktu atau penuh waktu) yang berasal dari enam Taman Kanak-kanak di Yogyakarta (Budi Mulia I Kaliurang, Primagama Kaliurang, ABA Purwodiningratan, Nurul Islam Ringroad Barat, BIAS Kaliurang, dan Budi Mulia Dua Seturan). Data penelitian diperoleh dengan menggunaka skala kompetensi sosial, kuesioner keluarga dan dokumentasi sekolah. Skala kompetensi sosial dinilai oleh guru kelas dengan menggunakan teknik interrater. Jumlah item pada skala kompetensi sosial adalah 30 item. Setelah uji coba terdapat 4 item yang gugur. Daya beda item berkisar dari 0,303-0,581 dengan angka reliabilitas 0,890. Sedangkan nilai reliabilitas antar rater berkisar antara 0,867-0,998. Hasil ANCOVA, diperoleh kesimpulan hasil penelitian bahwa: (1) ada perbedaan kompetensi sosial anak dengan tipe pendidikan prasekolah paruh waktu dan penuh waktu. Kompetensi sosial anak dengan tipe pendidikan prasekolah penuh waktu lebih tinggi daripada kompetensi sosial anak dengan tipe pendidikan prasekolah paruh waktu (F = 21,612; p = 0,000). (2) tidak ada korelasi antara kompetensi sosial anak yang berusia lima tahun sampai dengan enam tahun (F = 1,781; p = 0,184)

De novo 1q21.3q22 duplication revaluation in a “cold” complex neuropsychiatric case with syndromic intellectual disability

Syndromic intellectual disability often obtains a genetic diagnosis due to the combination of first and next generation sequencing techniques, although their interpretation may require revaluation over the years. Here we report on a composite neuropsychiatric case whose phenotype includes moderate intellectual disability, spastic paraparesis, movement disorder, and bipolar disorder, harboring a 1.802 Mb de novo 1q21.3q22 duplication. The role of this duplication has been reconsidered in the light of negativity of many other genetic exams, and of the possible pathogenic role of many genes included in this duplication, potentially configuring a contiguous gene-duplication syndrome

The integrability of Lie-invariant geometric objects generated by ideals in the Grassmann algebra

We investigate closed ideals in the Grassmann algebra serving as bases of Lie-invariant geometric objects studied before by E. Cartan. Especially, the E. Cartan theory is enlarged for Lax integrable nonlinear dynamical systems to be treated in the frame work of the Wahlquist Estabrook prolongation structures on jet-manifolds and Cartan-Ehresmann connection theory on fibered spaces. General structure of integrable one-forms augmenting the two-forms associated with a closed ideal in the Grassmann algebra is studied in great detail. An effective Maurer-Cartan one-forms construction is suggested that is very useful for applications. As an example of application the developed Lie-invariant geometric object theory for the Burgers nonlinear dynamical system is considered having given rise to finding an explicit form of the associated Lax type representation

Physical Activity, Obesity, Family History, and their Associations with Hypertension among The Elderly in Aceh Singkil, Aceh

Background: Hypertension is an important global health challenge due to its high prevalence and resulting cardiovascular disease and chronic kidney disease. This study aimed to examine the associations of physical activity, obesity, family history, with hypertension among the elderly in Aceh Singkil, Aceh. Subjects and Method: This was a case control study carried out in Aceh Singkil, Aceh. A sample of 132 elderly was selected for this study, consisting 66 elderly with hypertension and 66 elderly without hypertension. The dependent variable was hypertension. The independent variables were physical activity, obesity, and family history. Hypertension data was measured by sphygmomanometer. The other data were collected by questionnaire. The data were analyzed by a multiple logistic regression model. Results: Hypertension was associated with physical inactivity (OR= 5.12; 95% CI= 2.41 to 10.86; p<0.001), obesity (OR= 3.30; 95% CI= 1.61 to 6.74; p<0.001), and family history (OR= 7.73; 95% CI= 3.56 to 16.78; p<0.001). Conclusion: Physical inactivity, obesity, and family history, are associated with an increased risk of hypertension. Keywords: physical activity, obesity, family history, hypertensio

A selected ion flow tube study of the reactions of gas-phase cations with PSCl3

A selected ion flow tube was used to investigate the positive ion chemistry of thiophosphoryl chloride, PSCl$_3$. Rate coefficients and ion product branching ratios have been determined at room temperature for reactions with nineteen cations ; H$_3$O$^+$, CF$_3^+$, CF$^+$, NO$^+$, NO$_2^+$, SF$_2^+$, SF$^+$, CF$_2^+$, O$_2^+$, H$_2$O$^+$, N$_2$O$^+$, O$^+$, CO$_2^+$, CO$^+$, N$^+$, N$_2^+$, Ar$^+$, F$^+$ and Ne$^+$ (in order of increasing recombination energy). Complementary data described in the previous paper have been obtained for this molecule via the observation of threshold photoelectron photoion coincidences. For ions whose recombination energies are in the range 10-22 eV, comparisons are made between the product ion branching rations of PSCl$_3$ from photoionisation and from ion-molecule reactions. In most instances, the data from the two experiments are well correlated, suggesting that long-range charge transfer is the dominant mechanism for these ion-molecule reactions ; the agreement is particularly good for the atomic ions Ar$^+$, F$^+$ and Ne$^+$. Some reactions (e.g. O$_2^+$ + PSCl$_3$), however, exhibit significant differences; short-range charge transfer must then be occurring following the formation of an ion-molecule complex. For ions whose recombination energies are less than 10 eV (i.e. H$_3$O$^+$, CF$_3^+$, CF$^+$ and NO$^+$), reactions can only occur via a chemical process in which bonds are broken and formed, because the recombination energy of the cation is less than the ionisation energy of PSCl$_3$

Lie group analysis of a generalized Krichever-Novikov differential-difference equation

The symmetry algebra of the differential--difference equation $$\dot u_n = [P(u_n)u_{n+1}u_{n-1} + Q(u_n)(u_{n+1}+u_{n-1})+ R(u_n)]/(u_{n+1}-u_{n-1}),$$ where $P$, $Q$ and $R$ are arbitrary analytic functions is shown to have the dimension 1 \le \mbox{dim}L \le 5. When $P$, $Q$ and $R$ are specific second order polynomials in $u_n$ (depending on 6 constants) this is the integrable discretization of the Krichever--Novikov equation. We find 3 cases when the arbitrary functions are not polynomials and the symmetry algebra satisfies \mbox{dim}L=2. These cases are shown not to be integrable. The symmetry algebras are used to reduce the equations to purely difference ones. The symmetry group is also used to impose periodicity $u_{n+N}=u_n$ and thus to reduce the differential--difference equation to a system of $N$ coupled ordinary three points difference equations