Layer-dependent properties and noncollinear spin structure of epitaxial antiferromagnetic Mn films on Co/Cu(001)

The surface of expanded face-centered tetragonal antiferromagnetic Mn films of a few atomic monolayers thickness grown epitaxially on Co/Cu(001) was investigated at room temperature by scanning tunneling microscopy and scanning tunneling spectroscopy using a ferromagnetic ring-shaped bulk iron probe. We show that the main contribution to the contrast modulation observed as a function of Mn thickness in differential conductance maps is not due to spin- polarized tunneling from a layerwise antiferromagnetic spin alignment. Instead, it is mainly of electronic origin resulting from layer-dependent electronic properties of the Mn film, probably related to different levels of intermixing with Co atoms.On the atomic scale, theMn surface demonstrates a geometrical reconstruction with a (12 × 2) periodicity in two orthogonal domains on the fourfold symmetric substrate with an apparent surface corrugation of up to 0.3 A° . Simultaneously recorded differential conductance maps show different textures in the two orthogonal domains, providing evidence for noncollinearity in the Mn surface spin structure

The effect of bandwidth in scale-free network traffic

We model information traffic on scale-free networks by introducing the bandwidth as the delivering ability of links. We focus on the effects of bandwidth on the packet delivering ability of the traffic system to better understand traffic dynamic in real network systems. Such ability can be measured by a phase transition from free flow to congestion. Two cases of node capacity C are considered, i.e., C=constant and C is proportional to the node's degree. We figured out the decrease of the handling ability of the system together with the movement of the optimal local routing coefficient $\alpha_c$, induced by the restriction of bandwidth. Interestingly, for low bandwidth, the same optimal value of $\alpha_c$ emerges for both cases of node capacity. We investigate the number of packets of each node in the free flow state and provide analytical explanations for the optimal value of $\alpha_c$. Average packets traveling time is also studied. Our study may be useful for evaluating the overall efficiency of networked traffic systems, and for allevating traffic jam in such systems.Comment: 6 pages, 4 figure

Azimuthal angle for boson-jet production in the back-to-back limit

We show for the first time that the azimuthal angle between a vector boson and a jet, when using the Winner-Take-All recombination scheme, can be predicted at high precision in the back-to-back limit in the transverse plane. Specifically, we present a factorization theorem, and obtain numerical predictions at next-to-next-to-leading logarithmic (NNLL) accuracy. To allow for improved angular resolution, we provide results for track-based jet reconstruction, which only requires minimal changes in the calculation. We also find that linearly-polarized transverse momentum dependent (TMD) beam and jet functions enter at next-to-leading order (NLO) in the factorization theorem, originating from spin superpositions for one gluon, rather than the known case of spin correlations between gluons. We validate the switch from calorimetry to tracks using Pythia, and confirm the presence of linearly-polarized TMD functions using MCFM.Comment: 6 pages, 4 figure

Improving ART Pregnancy Rate with Two Kinds of Media and Two Types of Incubators

Culture media and incubators have played a key role in embryo quality. Here, we observed individual patient’s embryos to have different response for media and incubators. Patient’s 1850 zygotes were divided into two groups randomly and were cultured in Global and in P1 medium. The cleavage rate and embryo quality were recorded. The result showed that the cleavage, top quality embryos on Day 2 and Day 3 were not statistically different between media. However, 45% patient’s embryos grew very well in both Global and P1. 22% patient’s embryos grew well only in Global but poor quality in P1, while 21% grew well in the Global but poorly in the P1. Only 12% patient embryos did not grow well in both. The pregnant rate was only 40% in P1 or 42.5% in Global (P>0.05). However, when two media were used simultaneously, the pregnant rate increased to 70.1%. Also, two incubators showed significant higher pregnant rate than in single incubator (73.2% vs. 60%, P<0.05). In conclusion, the favorable response of individual patient’s embryos to media and incubators suggests that using two media and two incubators for embryo culture could significantly improve embryo quality and pregnant rates

Shock wave collisions in AdS5: approximate numerical solutions

We numerically study the evolution of a boost-invariant N=4 SYM medium using AdS/CFT. We consider a toy model for the collision of gravitational shock waves, finding that the energy density first increases, reaches a maximum and then starts to decrease, matching hydrodynamics for late times. For the initial conditions we consider, the hydrodynamic scale governing the late time behaviour is to very good approximation determined by the area of the black hole horizon at initial times. Our results provide a toy model for the early time evolution of the bulk system in heavy-ion collisions at RHIC and the LHC.Comment: 29 pages, 9 figure

Role of Particle Interactions in the Feshbach Conversion of Fermion Atoms to Bosonic Molecules

We investigate the Feshbach conversion of fermion atomic pairs to condensed boson molecules with a microscopic model that accounts the repulsive interactions among all the particles involved. We find that the conversion efficiency is enhanced by the interaction between boson molecules while suppressed by the interactions between fermion atoms and between atom and molecule. In certain cases, the combined effect of these interactions leads to a ceiling of less than 100% on the conversion efficiency even in the adiabatic limit. Our model predicts a non-monotonic dependence of the efficiency on mean atomic density. Our theory agrees well with recent experiments on $^6$Li and $^{40}$K.Comment: 5 pages, 4 figure

Raman and Infra-red properties and layer dependence of the phonon dispersions in multi-layered graphene

The symmetry group analysis is applied to classify the phonon modes of $N$-stacked graphene layers (NSGL's) with AB- and AA-stacking, particularly their infra-red and Raman properties. The dispersions of various phonon modes are calculated in a multi-layer vibrational model, which is generalized from the lattice vibrational potentials of graphene to including the inter-layer interactions in NSGL's. The experimentally reported red shift phenomena in the layer number dependence of the intra-layer optical C-C stretching mode frequencies are interpreted. An interesting low frequency inter-layer optical mode is revealed to be Raman or Infra-red active in even or odd NSGL's respectively. Its frequency shift is sensitive to the layer number and saturated at about 10 layers.Comment: enlarged versio

Transgenic Mice Convert Carbohydrates to Essential Fatty Acids

Transgenic mice (named “Omega mice”) were engineered to carry both optimized fat-1 and fat-2 genes from the roundworm Caenorhabditis elegans and are capable of producing essential omega-6 and omega-3 fatty acids from saturated fats or carbohydrates. When maintained on a high-saturated fat diet lacking essential fatty acids or a high-carbohydrate, no-fat diet, the Omega mice exhibit high tissue levels of both omega-6 and omega-3 fatty acids, with a ratio of ∼1∶1. This study thus presents an innovative technology for the production of both omega-6 and omega-3 essential fatty acids, as well as a new animal model for understanding the true impact of fat on human health