Impact of dark matter subhalos on extended HI disks of galaxies: Possible formation of HI fine structures and stars

Recent observations have discovered star formation activities in the extreme outer regions of disk galaxies. However it remains unclear what physical mechanisms are responsible for triggering star formation in such low-density gaseous environments of galaxies. In order to understand the origin of these outer star-forming regions, we numerically investigate how the impact of dark matter subhalos orbiting a gas-rich disk galaxy embedded in a massive dark matter halo influences the dynamical evolution of outer HI gas disk of the galaxy. We find that if the masses of the subhalos ($M_{\rm sb}$) in a galaxy with an extended HI gas disk are as large as $10^{-3} \times M_{\rm h}$, where $M_{\rm h}$ is the total mass of the galaxy's dark halo, local fine structures can be formed in the extended HI disk. We also find that the gas densities of some apparently filamentary structures can exceed a threshold gas density for star formation and thus be likely to be converted into new stars in the outer part of the HI disk in some models with larger $M_{\rm sb}$. These results thus imply that the impact of dark matter subhalos (``dark impact'') can be important for better understanding the origin of recent star formation discovered in the extreme outer regions of disk galaxies. We also suggest that characteristic morphologies of local gaseous structures formed by the dark impact can indirectly prove the existence of dark matter subhalos in galaxies. We discuss the origin of giant HI holes observed in some gas-rich galaxies (e.g., NGC 6822) in the context of the dark impact.Comment: 8 pages, 4 figures, accepted by ApJ

Tenth-Order QED Contribution to the Electron g-2 and an Improved Value of the Fine Structure Constant

This paper presents the complete QED contribution to the electron g-2 up to the tenth order. With the help of the automatic code generator, we have evaluated all 12672 diagrams of the tenth-order diagrams and obtained 9.16 (58)(\alpha/\pi)^5. We have also improved the eighth-order contribution obtaining -1.9097(20)(\alpha/\pi)^4, which includes the mass-dependent contributions. These results lead to a_e(theory)=1 159 652 181.78 (77) \times 10^{-12}. The improved value of the fine-structure constant \alpha^{-1} = 137.035 999 174 (35) [0.25 ppb] is also derived from the theory and measurement of a_e.Comment: 4 pages, 2 figures. Some numbers are slightly change

The Degrees of Freedom of Partial Least Squares Regression

The derivation of statistical properties for Partial Least Squares regression can be a challenging task. The reason is that the construction of latent components from the predictor variables also depends on the response variable. While this typically leads to good performance and interpretable models in practice, it makes the statistical analysis more involved. In this work, we study the intrinsic complexity of Partial Least Squares Regression. Our contribution is an unbiased estimate of its Degrees of Freedom. It is defined as the trace of the first derivative of the fitted values, seen as a function of the response. We establish two equivalent representations that rely on the close connection of Partial Least Squares to matrix decompositions and Krylov subspace techniques. We show that the Degrees of Freedom depend on the collinearity of the predictor variables: The lower the collinearity is, the higher the Degrees of Freedom are. In particular, they are typically higher than the naive approach that defines the Degrees of Freedom as the number of components. Further, we illustrate how the Degrees of Freedom approach can be used for the comparison of different regression methods. In the experimental section, we show that our Degrees of Freedom estimate in combination with information criteria is useful for model selection.Comment: to appear in the Journal of the American Statistical Associatio

Convergence of the Allen-Cahn equation with Neumann boundary conditions

We study a singular limit problem of the Allen-Cahn equation with Neumann boundary conditions and general initial data of uniformly bounded energy. We prove that the time-parametrized family of limit energy measures is Brakke's mean curvature flow with a generalized right angle condition on the boundary.Comment: 26 pages, 1 figur

On the Ecology and Distribution of \u3ci\u3eEchinococcus\u3c/i\u3e spp. (Cestoda: Taeniidae), and Characteristics of Their Development in the Intermediate Host. II. Comparative Studies on the Development of Larval \u3ci\u3eE. multilocularis\u3c/i\u3e Leuckart, 1863, in the Intermediate Host

This paper reports the results of a comparative study of the development of the larval Echinococcus multilocularis Leuckart, 1863), and associated tissue reaction in naturally and experimentally infected mammals representing 31 species. The histogenesis of the larval cestode was traced in detail in arvicoline rodents of several species, and interspecific differences were defined. In arvicoline rodents, the developing larva exhibited host-specific characteristics within about a month after infection was established. The tissue reaction in Microtus oeconomus was characterized by the production of a large quantity of detritus around the larva, and by the formation of a thick epithelioid zone. In one subspecies, M. oeconomus innuitus, development of the larva was retarded, and the detrital mass was often calcified; in another, M. oeconomus operarius, the detritus rarely became calcified and the larva proliferated more rapidly. In M. pennsylvanicus, the tissue reaction was minimal, and little detritus was present. The characteristics of the tissue reaction in M. montebelli placed it in an intermediate position between the aforementioned species. In Clethrionomys rutilus, a thin epithelioid zone and an outer zone of loose collagenous fibers composed the adventitial layer; exogenous budding was retarded in this vole. A minimal tissue reaction occurred in Lagurus curtatus. In Lemmus spp., larger cysts were characteristic, but areas of small-cystic proliferation were always present. Similar differences in species or subspecies of Citellus and Dicrostonyx were described. Lesions of alveolar bydatid disease in man also were studied. The invasive growth of the larval cestode in the human liver involves a process comparable to small-cystic proliferation in the natural intermediate hosts. Although the later stages of development of the larval cestode are inhibited in man, exogenous proliferation of vesicles continues for the life of the host. The lesion in man was compared with a morphologically similar formation produced by anomalous development of the larval E. granulosus in the bovine liver. The latter is distinguished by the absence of areas of small-cystic proliferation. Non-echinococcal lesions found in the tissues studied, some of which resembled foci caused by the larval E. multilocularis, were briefly discussed

Kaluza-Klein Multi-Black Holes in Five-Dimensional Einstein-Maxwell Theory

We construct the Kaluza-Klein multi-black hole solutions on the Gibbons-Hawking multi-instanton space in the five-dimensional Einstein-Maxwell theory. We study geometric properties of the multi-black hole solutions. In particular, unlike the Gibbons-Hawking multi-instanton solutions, each nut-charge is able to take a different value due to the existence of black hole on it. The spatial cross section of each horizon can be admitted to have the topology of a different lens space L(n;1)=S^3/Z_n addition to S^3.Comment: 8 pages, to be published in Classical and Quantum Gravit

d-like Symmetry of the Order Parameter and Intrinsic Josephson Effects in Bi2212 Cross-Whisker Junctions

An intrinsic tunnel junction was made using two Bi-2212 single crystal whiskers. The two whiskers with a cross-angle were overlaid at their c-planes and connected by annealing. The angular dependence of the critical current density along the c-axis is of the d-wave symmetry. However, the angular dependence is much stronger than that of the conventional d-wave. Furthermore, the current vs. voltage characteristics of the cross-whiskers junctions show a multiple-branch structure at any cross-angle, indicating the formation of the intrinsic Josephson junction array.Comment: 4 pages PDF fil

Histologic Alterations Produced by Chrysarobin (1,8-dihydroxy-3-methyl-9-anthrone) in SENCAR Mouse Skin: Relationship to Skin Tumor Promoting Activity

Histologic changes induced in SENCAR skin following a single treatment with chrysarobin (1,8-dihydroxy-3-methyl-9-anthrone) exhibited differences in time course from that observed with 12-O-tetradecanoylphorbol-13-acetate (TPA). Although not significantly different, maximum elevations in epidermal thickness, total number of nucleated epidermal cells, and dark basal keratinocytes (DCs) induced by 220nmol chrysarobin occurred at 96h after treatment, while those induced by 3.4nmol TPA occurred at 48h. Both compounds elicited comparable inflammatory responses. Twice-weekly applications of chrysarobin for 2.5 weeks induced a moderate hyperplasia, increase in total nucleated epidermal cells, and increased DCs at 48 and 96h after the last treatment, with a higher value for these parameters occurring at 48h. Interestingly, the magnitude of these changes was similar to that observed after a single application. In contrast, twice-weekly applications of TPA induced a dramatic, potentiated induction of epidermal hyperplasia and DCs. Once-weekly applications of chrysarobin led to a potentiated induction of both hyperplasia and DCs compared to the twice-weekly treatment regimen and also more effectively promoted epidermal papillomas in previously initiated SENCAR mice. Skin sections from mice treated with chrysarobin displayed overt signs of epidermal toxicity including altered basal cell morphology and a decreased number of basal cells per 125μm of basement membrane. Hyperplasia induced by multiple but not single treatments with chrysarobin and TPA correlated quantitatively with their papilloma promoting activity. In addition, the data suggest that epidermal toxicity may play a role in tumor promotion by anthrones

A method of enciphering quantum states

In this paper, we propose a method of enciphering quantum states of two-state systems (qubits) for sending them in secrecy without entangled qubits shared by two legitimate users (Alice and Bob). This method has the following two properties. First, even if an eavesdropper (Eve) steals qubits, she can extract information from them with certain probability at most. Second, Alice and Bob can confirm that the qubits are transmitted between them correctly by measuring a signature. If Eve measures m qubits one by one from n enciphered qubits and sends alternative ones (the Intercept/Resend attack), a probability that Alice and Bob do not notice Eve's action is equal to (3/4)^m or less. Passwords for decryption and the signature are given by classical binary strings and they are disclosed through a public channel. Enciphering classical information by this method is equivalent to the one-time pad method with distributing a classical key (random binary string) by the BB84 protocol. If Eve takes away qubits, Alice and Bob lose the original quantum information. If we apply our method to a state in iteration, Eve's success probability decreases exponentially. We cannot examine security against the case that Eve makes an attack with using entanglement. This remains to be solved in the future.Comment: 21 pages, Latex2e, 10 epsf figures. v2: 22 pages, added two references, several clarifying sentences are added in Sec. 5, typos corrected, a new proof is provided in Appendix A and it is shorter than the old one. v3: 23 pages, one section is adde