We observe a signal for the doubly charmed baryon Xi(+)(cc) in the charged decay mode Xi(+)(cc)-->Lambda(+)(c)K-pi(+) in data from SELEX, the charm hadroproduction experiment at Fermilab. We observe an excess of 15.9 events over an expected background of 6.1+/-0.5 events, a statistical significance of 6.3sigma. The observed mass of this state is 3519+/-1 MeV/c(2). The Gaussian mass width of this state is 3 MeV/c(2), consistent with resolution; its lifetime is less than 33 fs at 90% confidence.

Ultrasmall biocompatible WO3 - x nanodots with an outstanding X-ray radiation sensitization effect are prepared, and demonstrated to be applicable for multi-modality tumor imaging through computed tomography and photoacoustic imaging (PAI), and effective cancer treatment combining both photothermal therapy and radiation therapy.

We observe a signal for the doubly charmed baryon Ξ + cc in the decay mode Ξ + cc → pD + K − to complement the previous reported decay Ξ + cc → Λ + c K − π + in data from SELEX, the charm hadroproduction experiment at Fermilab. In this new decay mode we observe an excess of 5.62 events over a combinatoric background estimated by event mixing to be 1.38 ± 0.13 events. The mixed background has Gaussian statistics, giving a signal significance of 4.8σ. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4 × 10 −4. The observed mass of this state is 3518 ± 3 MeV/c 2 , consistent with the published result. Averaging the two results gives a mass of 3518.7 ± 1.7 MeV/c 2. The observation of this new weak decay mode confirms the previous SELEX suggestion that this state is a double charm baryon. The relative branching ratio for these two modes is 0.36 ± 0.21.

The Σ − mean squared charge radius has been measured in the space-like Q 2 range 0.035-0.105 GeV 2 /c 2 by elastic scattering of a Σ − beam off atomic electrons. The measurement was performed with the SELEX (E781) spectrometer using the Fermilab hyperon beam at a mean energy of 610 GeV/c. We obtain r 2 ch Σ − = (0.61 ± 0.12 (stat.) ± 0.09 (syst.)) fm 2 . The proton and π − charge radii were measured as well and are consistent with results of other experiments. Our result agrees with the recently measured strong interaction radius of the Σ − .

In this paper, we study the parabolic-elliptic Keller-Segel system with singular sensitivity and logistic-type source: u t = ∆u − χ∇·( u v ∇v)+ ru − µu k , 0 = ∆v − v + u under the non-flux boundary conditions in a smooth bounded convex domain Ω ⊂ R n , χ, r, µ > 0, k > 1 and n ≥ 2. It is shown that the system possesses a globally bounded classical solution if k > 3n−2 n , and r > χ 2 4 for 0 < χ ≤ 2, or r > χ − 1 for χ > 2. In addition, under the same condition for r, χ, the system admits a global generalized solution when k ∈ (2 − 1 n , 3n−2 n ], moreover this global generalized solution should be globally bounded provided r µ and the initial data u 0 suitably small.

This paper deals with the higher dimension quasilinear parabolic-parabolic Keller-Segel system involving a source term of logistic typein Ω × (0, T ), subject to nonnegative initial data and homogeneous Neumann boundary condition, where Ω is smooth and bounded domain in R n , n ≥ 2, φ and g are smooth and positive functions satisfyingIt was known that the model without the logistic source admits both bounded and unbounded solutions, identified via the critical exponent 2 n . On the other hand, the model is just a critical case with the balance of logistic damping and aggregation effects, for which the property of solutions should be determined by the coefficients involved. In the present paper it is proved that there is θ 0 > 0 such that the problem admits global bounded classical solutions, regardless of the size of initial data and diffusion whenever χ µ < θ 0 . This shows the substantial effect of the logistic source to the behavior of solutions.

We get simple conditions under which the elliptic system y⌬u s u p 1¨q1 , y⌬s u p 2¨q 2 in R n , n G 3 with p q q ) 1, i s 1, 2 has no positive radially symmetric i i solutions. Then by using this nonexistence result, we establish blow-up estimates for reaction-diffusion system of Fujita type u s ⌬ u q u p 1¨q1 ,¨s ⌬¨q u p 2¨q 2 t t with the homogeneous Dirichlet boundary value condition. ᮊ

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