Low-mass dilepton production in pppp and AAAA collisions

We adopt a factorized QCD formalism to describe the transverse momentum distribution of low-mass lepton pairs produced in $pp$ collisions, when the pair transverse momentum $Q_T \gg Q$, with the pair's invariant mass $Q$ as low as $Q \sim \Lambda_{\mathrm{QCD}}$. We extend this formalism to dilepton production in $AA$ collisions by including the nuclear-dependent power correction due to parton multiple scattering.Comment: 4 pages, 1 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

Test of the Universality of Naive-time-reversal-odd Fragmentation Functions

We investigate the ''spontaneous'' hyperon transverse polarization in $e^+e^-$ annihilation and semi-inclusive deep inelastic scattering processes as a test of the universality of the naive-time-reversal-odd transverse momentum dependent fragmentation functions. We find that universality implies definite sign relations among various observables. This provides a unique opportunity to study initial/final state interaction effects in the fragmentation process and test the associated factorization.Comment: 4 pages, 3 figure

Comparison of Online 6 Degree-of-Freedom Image Registration of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac X-Ray for Intracranial Radiosurgery.

PURPOSE: The study was aimed to compare online 6 degree-of-freedom image registrations of TrueBeam cone-beam computed tomography and BrainLab ExacTrac X-ray imaging systems for intracranial radiosurgery. METHODS: Phantom and patient studies were performed on a Varian TrueBeam STx linear accelerator (version 2.5), which is integrated with a BrainLab ExacTrac imaging system (version 6.1.1). The phantom study was based on a Rando head phantom and was designed to evaluate isocenter location dependence of the image registrations. Ten isocenters at various locations representing clinical treatment sites were selected in the phantom. Cone-beam computed tomography and ExacTrac X-ray images were taken when the phantom was located at each isocenter. The patient study included 34 patients. Cone-beam computed tomography and ExacTrac X-ray images were taken at each patient\u27s treatment position. The 6 degree-of-freedom image registrations were performed on cone-beam computed tomography and ExacTrac, and residual errors calculated from cone-beam computed tomography and ExacTrac were compared. RESULTS: In the phantom study, the average residual error differences (absolute values) between cone-beam computed tomography and ExacTrac image registrations were 0.17 ± 0.11 mm, 0.36 ± 0.20 mm, and 0.25 ± 0.11 mm in the vertical, longitudinal, and lateral directions, respectively. The average residual error differences in the rotation, roll, and pitch were 0.34° ± 0.08°, 0.13° ± 0.09°, and 0.12° ± 0.10°, respectively. In the patient study, the average residual error differences in the vertical, longitudinal, and lateral directions were 0.20 ± 0.16 mm, 0.30 ± 0.18 mm, 0.21 ± 0.18 mm, respectively. The average residual error differences in the rotation, roll, and pitch were 0.40°± 0.16°, 0.17° ± 0.13°, and 0.20° ± 0.14°, respectively. Overall, the average residual error differences wer

Low-mass lepton pair production at large transverse momentum

We study the transverse momentum distribution of low-mass lepton pairs produced in hadronic scattering, using the perturbative QCD factorization approach. We argue that the distribution at large transverse momentum, $Q_T \gg Q$, with the pair's invariant mass $Q$ as low as $Q \sim \Lambda_{\mathrm{QCD}}$, can be systematically factorized into universal parton-to-lepton pair fragmentation functions, parton distributions, and perturbatively calculable partonic hard parts evaluated at a short distance scale $\sim {\cal O}(1/Q_T)$. We introduce a model for the input lepton pair fragmentation functions at a scale $\mu_0\sim 1$ GeV, which are then evolved perturbatively to scales relevant at RHIC. Using the evolved fragmentation functions, we calculate the transverse momentum distributions in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions at RHIC. We also discuss the sensitivity of the transverse momentum distribution of low-mass lepton pairs to the gluon distribution.Comment: 16 pages, 11 figures, revised version to appear in Phys. Rev.

Capacity development platform for promoting efficient urban water management: Event Report

The present paper summarizes the results of an application initiated within the framework of 35 years celebration of diplomatic relations between Germany and Vietnam. Within this context, the Technische Universität Dresden (TUD) and the Academy of Managers for Construction and Cities (AMC) jointly organized in 2010 a series of four thematic workshops. The one-day events have had similar structures and focused on main subjects of interest in the water sectors of both countries. In Vietnam, the workshops took place in Ha Noi, Hai Phong, Nha Trang and Vung Tau. Best practice examples about conceptualization, operation and maintenance of municipal water works provided an insight view into the challenges currently faced by the water service providers. TUD and AMC, together with their German and Vietnamese partners, addressed these issues by organizing the consecutive workshops under the umbrella of Vietnamese Water Supply and Sewerage Association (VWSA) and in coordination with the German Water Partnership (GWP).Bài báo trình bày tóm tắt các kết quả của một đề xuất trong khuôn khổ kỷ niệm 35 năm quan hệ ngoại giao giữa CHLB Đức và Việt Nam. Theo đó, Trường Đại học Tổng hợp Kỹ Thuật Dresden (TUD) và Học viện Quản lý Xây dựng và Đô thị (AMC) đã phối hợp tổ chức một chuỗi bốn hội thảo chuyên đề trong năm 2010. Mỗi hội thảo thực hiện trong một ngày chương trình giống nhau và tập trung vào các chủ đề chính mà cả hai quốc gia đều quan tâm trong lĩnh vực nước. Phía Việt Nam, các hội thảo được tổ chức ở các thành phố Hà Nội, Hải Phòng, Nha Trang và Vũng Tàu. Nhiều bài thuyết trình về khái niệm hóa, vận hành và bảo dưỡng các công trình cấp nước đô thị đã thảo luận sâu về những thách thức mà các dịch vụ cấp nước đang gặp phải. TUD và AMC, kết hợp với các đối tác CHLB Đức và Việt Nam, đã ghi nhận các vấn đề phát sinh thông qua việc tổ chức nhiều hội thảo liên tục dưới sự bảo trợ của Hiệp hội Cấp thoát nước Việt Nam (VWSA) và Hiệp hội nước CHLB Đức (GWP)

Accessing tri-gluon correlations in the nucleon via the single spin asymmetry in open charm production

We calculate the single transverse-spin asymmetry for open charm production in $pp$ collisions within the QCD collinear factorization approach. We include contributions from both twist-three quark-gluon and tri-gluon correlation functions. We find that the quark-gluon correlation functions alone generate only a very small asymmetry for open charm production in the kinematic region of current interest at RHIC, so that the observation of any significant single-spin asymmetry would be a clear indication of the presence of tri-gluon correlations inside a polarized proton. We furthermore demonstrate that the tri-gluon contribution could be very different for the production of $D$ and $\bar{D}$ mesons. These features make the single spin asymmetry in open charm production in polarized $pp$ collisions at RHIC an excellent probe of tri-gluon correlation functions.Comment: 10 pages, 7 figure

Recent Advances in X-Ray Microanalysis in Dermatology

Electron microprobe and proton microprobe X-ray analysis can be used in several areas of dermatological research. With a proton probe, the distribution of trace elements in human hair can be determined. In contrast to sulfur, which is homogeneously distributed, calcium, iron, and zinc appear to be non-homogeneously distributed over the hair cross-section. Electron microprobe analysis on freeze-dried cryosections of guinea-pig and human epidermis shows a marked gradient of Na, P and K over the stratum granulosum. In sections of freeze-substituted human skin this gradient is less steep. This difference is likely to be due to a decrease in water content of the epidermis towards the stratum corneum. Electron microprobe analysis of the epidermis can, for analysis of trace elements, be complemented by the proton microprobe. Quantitative agreement between the two techniques can be obtained by the use of a standard. Proton micro probe analysis was used to determine the distribution of Ni or Cr in human epidermis exposed to nickel or chromate ions. Possible differences in water content between the stratum corneum of patients with atopic eczema and normal stratum corneum was investigated in skin freeze- substituted with Br-doped resin. No significant differences were observed. Proliferative reactions in the epidermis appear to be associated with increased levels of the elements P and K. Such changes were found in guinea-pig skin after exposure to sodium lauryl sulfate, and in plaques of skin from patients with psoriasis

Phenol-rich fulvic acid as a water additive enhances growth, reduces stress, and stimulates the immune system of fish in aquaculture

Aquaculture has become imperative to cover the demands for dietary animal protein. Simultaneously, it has to overcome prejudices from excessive use of antibiotics and environmental impacts. Natural supplements are traditionally applied orally. In this study, we demonstrated another pathway: the gills. Humic substances are immunostimulants and a natural part of every aquatic ecosystem, making them ideal to be used as bath stimulants. Five and 50 mg C/L of a fulvic acid-rich humic substance was added for 28 days to the water of juvenile rainbow trout (Oncorhynchus mykiss). This fulvic acid is characterized by a high content of phenolic moieties with persistent free radicals and a high electron exchange capacity. The high concentration of the fulvic acid significantly increased growth and reduced the food conversion ratio and the response to a handling-stressor. Phagocytosis and potential killing activity of head kidney leukocytes were increased, as well as the total oxyradical scavenging capacity (TOSC) and lysozyme activity in the gills. In conclusion, immunostimulation via gills is possible with our fulvic acid, and the high phenolic content improved overall health and stress resistance of fish.Bundesministerium für Wirtschaft und Energie http://dx.doi.org/10.13039/501100006360Projekt DEALPeer Reviewe