Synchronous solutions and their stability in nonlocally coupled phase oscillators with propagation delays

We study the existence and stability of synchronous solutions in a continuum field of non-locally coupled identical phase oscillators with distance-dependent propagation delays. We present a comprehensive stability diagram in the parameter space of the system. From the numerical results a heuristic synchronization condition is suggested, and an analytic relation for the marginal stability curve is obtained. We also provide an expression in the form of a scaling relation that closely follows the marginal stability curve over the complete range of the non-locality parameter.Comment: accepted in Phys. Rev. E (2010

Dirac nodal line metal for topological antiferromagnetic spintronics

Topological antiferromagnetic (AFM) spintronics is an emerging field of research, which exploits the N\'eel vector to control the topological electronic states and the associated spin-dependent transport properties. A recently discovered N\'eel spin-orbit torque has been proposed to electrically manipulate Dirac band crossings in antiferromagnets; however, a reliable AFM material to realize these properties in practice is missing. Here, we predict that room temperature AFM metal MnPd$_{2}$ allows the electrical control of the Dirac nodal line by the N\'eel spin-orbit torque. Based on first-principles density functional theory calculations, we show that reorientation of the N\'eel vector leads to switching between the symmetry-protected degenerate state and the gapped state associated with the dispersive Dirac nodal line at the Fermi energy. The calculated spin Hall conductivity strongly depends on the N\'eel vector orientation and can be used to experimentally detect the predicted effect using a proposed spin-orbit torque device. Our results indicate that AFM Dirac nodal line metal MnPd$_{2}$ represents a promising material for topological AFM spintronics

Spin-torque switching of noncollinear antiferromagnetic antiperovskites

Antiferromagnetic (AFM) spintronics exploits the Néel vector as a state variable for novel electronic devices. Recent studies have demonstrated that the Néel vector can be switched by a spin-orbit torque. These studies however are largely limited to collinear antiferromagnets of proper magnetic space-group symmetry. There is, however, a large group of high-temperature noncollinear antiferromagnets, which are suitable for such switching. Here, we predict that spin torque can be efficiently used to switch a noncollinear AFM order in antiperovskite materials. Based on first-principles calculations and atomistic spin-dynamics modeling, we show that in antiperovskites ANMn3 (A = Ga, Ni, etc.) with the AFM Γ4g ground state, the AFM order can be switched on the picosecond timescale using a spin torque generated by a spin current. The threshold switching current density can be tuned by the ANMn3 stoichiometry engineering, changing the magnetocrystalline anisotropy. The Γ4g AFM phase supports a sizable anomalous Hall effect, which can be used to detect the spin-torque switching of the AFM order. The predicted ultrafast switching dynamics and the efficient detection of the AFM order state make noncollinear magnetic antiperovskites a promising material platform for AFM spintronics

Neuroimaging in paediatric patients with developmental delay

Background: Aim and objectives of the study were to radiologically evaluate paediatric patients with developmental delay (DD), assess the relative prevalence of abnormal brain MRI, further categorize them based on the abnormal imaging findings and structures affected. The purpose of this study is to diagnose the underlying etiology that helps in early treatment and amelioration of the condition, parental counselling regarding the outcome of the child, providing an estimate of child’s developmental potential and the recurrence risk in siblings.Methods: 135 paediatric patients of the age 3 months to 15 years with DD referred to department of radiology were investigated with MRI scans of the brain via 1.5T Siemens scanner after making the child sleep or sedated. The sequences used were: axial T1, axial T2, axial FLAIR, axial DWI, axial ADC, axial SWI, axial PHASE, sagittal T1 and coronal FLAIR. CT scan of the brain was done only when indicated on 128 slice Siemens Somatom perspective scanner. Informed consent shall be taken from patient’s parents. Clinical and demographic details of the enrolled patients were noted in the Performa. Data collected was analysed using descriptive and inferential statistics.Results: Out of 135 children with DD, 69.1% (n=92) were male and 31.9% (n=43) were female. Majority of these children belonged to 3 months to 1 year and 2 to 5 years of age group. About 81.4% (n=110) of children with DD had abnormal findings in MRI. Among children with abnormal MRI findings, 42.9% had hypoxic ischemic changes, 6.6% had congenital malformations and non-specific causes, respectively 4.4% had neurodegenerative and occlusive neurovascular conditions, respectively 3.7% had CSF disorders and neoplasms, respectively 2.9% had infection associated changes and non-traumatic intracranial bleed, respectively 2.2% had metabolic disorders and 0.7% had demyelination. Majority of cases had ventricular abnormality, followed by the corpus callosum.Conclusions: DD presents with a wide spectrum of etiologies, clinical findings and MRI features ranging from completely normal to abnormal. The present study could establish the various morphological appearances of DD on MRI and further categorize them into various subgroups be effective in diagnosis, management and prognosis determination processes

Structural studies of 1:1 quinone-hydroquinone complexes

The structures of the 1:1 quinone-hydroquinone complexes of 2-phenyl and of 2-(4'-chloro) phenylbenzoquinone have been studied by X-ray methods. A superficial study would indicate that the quinhydrones are centrosymmetric and belong to the space group P21/c. However, other evidence indicates that the true crystal structure may belong to either the space group P21 or to Pc, or that the crystal may contain regions that would coresspond to each of these two non-centrosymmetric space groups. Some possible consequences of such a structural arrangement are briefly discussed

Mass independence and asymmetry of the reaction: Multi-fragmentation as an example

We present our recent results on the fragmentation by varying the mass asymmetry of the reaction between 0.2 and 0.7 at an incident energy of 250 MeV/nucleon. For the present study, the total mass of the system is kept constant (ATOT = 152) and mass asymmetry of the reaction is defined by the asymmetry parameter (? = | (AT - AP)/(AT + AP) |). The measured distributions are shown as a function of the total charge of all projectile fragments, Zbound. We see an interesting outcome for rise and fall in the production of intermediate mass fragments (IMFs) for large asymmetric colliding nuclei. This trend, however, is completely missing for large asymmetric nuclei. Therefore, experiments are needed to verify this prediction

Multidetector computed tomographic urography for evaluation of vascular and ureteric anomalies associated with ectopic kidneys

Background: The purpose of this study is to evaluate the vascular and ureteric anomalies associated with ectopic kidneys with multidetector computed tomography (MDCT). Methods: The 40 patients with pre-diagnosed ectopic kidney undergoing MDCT urography (Contrast study) and KUB (Plain study) were included in this cross-sectional observational study. The location and number of bilateral kidneys were assessed. The number and origin of the renal arteries and renal veins were noted. Their relationship with each other and possible complications in surgical handling analysed. Data collected was analysed using descriptive and inferential statistics.Results: The renal artery originated from suprarenal aorta in 2 cases, normal origin in 10 cases, infrarenal aorta in 12 cases, aortic bifurcation in 19 cases, common iliac artery in 6 cases and iliac artery bifurcation in 2 cases. The renal vein was of normal origin in 8 cases, originated from infrarenal inferior vena cava (IVC) in 16 cases, IVC bifurcation in 14 cases, common iliac vein in 9 cases, internal iliac vein in 2 cases and external iliac vein in 1 case. There was a significant correlation between the level of ectopic kidneys (abdominal, iliac and pelvis) and level of origin of arteries (p<0.001) and veins (p<0.001). In addition, significant correlation was found between the origins of arteries and veins of ectopic kidneys (p<0.001).Conclusions: A knowledge of the possible variations in renal vasculature and ureter associated with ectopic kidneys can play a key role in preventing iatrogenic hemorrhage during surgery

Radiative correction to the lightest neutral Higgs mass in warped supersymmetry

We compute radiative correction to the lightest neutral Higgs mass ($m_h$) induced by the Kaluza-Klein (KK) towers of fermions and sfermions in a minimal supersymmetric scenario embeded in a 5-dimensional warped space. The Higgs is confined to the TeV brane. The KK spectra of matter supermultiplets is tied to the explanation of the fermion mass hierarchy problem. We demonstrate that for a reasonable choice of extra-dimensional parameters, the KK-induced radiative correction can enhance the upper limit on $m_h$ by as much as 100 GeV beyond the 4d limit of 135 GeV.Comment: 6 pages, 2 figures; v2: comments on dark matter added, to appear in Physical Review D (Rapid Communication