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Search Results: 1 - 10 of 192706 matches for " Timo D. Stark "
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Ethnopharmacological Survey of Plants Used in the Traditional Treatment of Gastrointestinal Pain, Inflammation and Diarrhea in Africa: Future Perspectives for Integration into Modern Medicine
Timo D. Stark,Dorah J. Mtui,Onesmo B. Balemba
Animals , 2013, DOI: 10.3390/ani3010158
Abstract: There is a growing need to find the most appropriate and effective treatment options for a variety of painful syndromes, including conditions affecting the gastrointestinal tract, for treating both veterinary and human patients. The most successful regimen may come through integrated therapies including combining current and novel western drugs with acupuncture and botanical therapies or their derivatives. There is an extensive history and use of plants in African traditional medicine. In this review, we have highlighted botanical remedies used for treatment of pain, diarrheas and inflammation in traditional veterinary and human health care in Africa. These preparations are promising sources of new compounds comprised of flavonoids, bioflavanones, xanthones, terpenoids, sterols and glycosides as well as compound formulas and supplements for future use in multimodal treatment approaches to chronic pain, gastrointestinal disorders and inflammation. The advancement of plant therapies and their derivative compounds will require the identification and validation of compounds having specific anti-nociceptive neuromodulatory and/or anti-inflammatory effects. In particular, there is need for the identification of the presence of compounds that affect purinergic, GABA, glutamate, TRP, opioid and cannabinoid receptors, serotonergic and chloride channel systems through bioactivity-guided, high-throughput screening and biotesting. This will create new frontiers for obtaining novel compounds and herbal supplements to relieve pain and gastrointestinal disorders, and suppress inflammation.
Class of Service Support Layer for Wireless Mesh Networks  [PDF]
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.32021
Abstract: This paper presents an add-on Class of Service (CoS) layer for wireless mesh networks. The proposed protocol is applicable for contention-based MACs and is therefore compatible with most of the Wireless Local Area Network (WLAN) and Wireless Sensor Network (WSN) protocols. The protocol has a locally centralized control for managing data flows, which either reserve a fixed bandwidth or are weighted by fair scheduling. The protocol reduces transmission collisions, thus improving the overall throughput. IEEE 802.11 adhoc WLAN has been taken as a platform for simulations and prototyping for evaluating the protocol performance. Network Simulator Version 2 (NS2) simulations show that the CoS protocol efficiently differentiates bandwidth, supports bandwidth reservations, and reaches less than 10 ms transfer delay on IEEE 802.11b WLAN. Testing with a full prototype implementation verified the performance of the protocol.
Interaktivit t als Erfolgsfaktor für die Gewinnung von Aufmerksamkeit? Einige Ergebnisse am Beispiel von GIGA TV
Thomas D?bler,Birgit Stark
Kommunikation@gesellschaft , 2001,
Abstract: Was bewegt Personen sich mehrere Stunden t glich an einem nach herk mmlichen Kriterien beurteilten "langweiligen" Programm aktiv zu beteiligen? Ist es die durch Interaktivit t bedingte M glichkeit, das Programm nicht nur mitgestalten, sondern darüber auch Aufmerksamkeit erlangen zu k nnen? Liegt etwa der Erfolg von GIGA, dem "ersten wirklich interaktiven Sender der Welt", so die Eigenwerbung, im Wettbewerb um Aufmerksamkeit begründet? Hat Interaktivit t beim Fernsehen eine Funktion in der Gewinnung von Aufmerksamkeit und vermag unter Rückgriff auf die Aufmerksamkeitshypothese die Nennung des eigenen Nicknames oder auch der von Freunden, den Erfolg von GIGA ganz wesentlich erkl ren? Die Ergebnisse einer Online-Befragung von GIGA-Nutzern zeigen, dass das Interesse an dem interaktiven Programm über den Rückkanal Internet stark von einer gut aufgebauten und funktionierenden Community abh ngt. Je st rker n mlich die Zuschauer sich mit der Sendung identifizieren und je fter sie im Netz an Diskussionen oder Chats teilnehmen, desto st rker wird auch die Motivation zur Interaktion. Allerdings wird die intensive Nutzung der Interaktivit tsoptionen und damit auch die Chance über namentlich genannte Mitgestaltung der Sendung Aufmerksamkeit zu erlangen, letztlich nur von einer Minderheit betrieben. Damit muss die so allgemeingültig und umfassend formulierte Aufmerksamkeitshypothese zumindest für die betrachtete Untersuchungsgruppe in Frage gestellt werden; darüber hinaus erscheint aber auch eine übertragung der interaktiven Erfolgsgeschichte von GIGA auf andere Zuschauergruppen nur deutlich eingeschr nkt m glich.
Impacts of waveforms on the fluid flow, wall shear stress, and flow distribution in cerebral aneurysms and the development of a universal reduced pressure  [PDF]
Noel M. Naughton, Brian D. Plourde, John R. Stark, Simona Hodis, John P. Abraham
Journal of Biomedical Science and Engineering (JBiSE) , 2014, DOI: 10.4236/jbise.2014.71002

The hydrodynamics of aneurysm blood flow is thought to be a critical factor in the evolution and potential rupture of blood vessel walls. The ability to predict which aneurysms may grow or rupture has eluded researchers and practicing clinicians. On the other hand, it is expected that local flow patterns, pressures, and wall shear stress play a role in the aneurysm life. In this study, the impact of waveform on these parameters was studied. A baseline waveform, taken from a patient, was applied to an aneurysm geometry. Then the waveform was modified by increasing and decreasing both the flowrates and the cardiac rate. In total, seven cases were investigated. It was found that there were remarkable similarities in the patterns of flow and wall stresses for the cases. These similarities existed throughout the cardiac cycle. It was also found that there was a reduced pressure variable that provides a universal relationship that characterizes all of the cases. It was seen that the maximum wall shear occurs at the neck of the aneurysm and scales with the peak systolic velocity. Finally, it is shown that the flow distribution to the multiple outlets does not appreciably depend on the details of the inlet waveform. All cases had a flow distribution that was within 2%.

Influence of Supporting Tissue on the Deformation and Compliance of Healthy and Diseased Arteries  [PDF]
Biyuan Sun, Lauren J. Vallez, Brian D. Plourde, John P. Abraham, John R. Stark
Journal of Biomedical Science and Engineering (JBiSE) , 2015, DOI: 10.4236/jbise.2015.88046
Abstract: Hemodynamics and the interaction between the components of the cardiovascular system are complex and involve a structural/fluid flow interaction. During the cardiac cycle, changes to vascular pressure induce a compliant response in the vessels as they cyclically stretch and relax. The compliance influences the fluid flow throughout the system. The interaction is influenced by the disease state of the artery, and in particular, a plaque layer can reduce the compliance. In order to properly quantify the fluid-structural response, it is essential to consider whether the tissue surrounding the artery provides a support to the vessel wall. Here, a series of calculations are provided to determine what role the supporting tissue plays in the vessel wall and how much tissue must be included to properly carry out future fluid-structure calculations. Additionally, we calculate the sensitivity of the compliance to material properties such as the Young’s modulus or to the transmural pressure difference.
B Physics at D0
Jan Stark,for the D0 Collaboration
Physics , 2004,
Abstract: The Fermilab Tevatron (p pbar), operating at sqrt(s)=1.96 TeV, is a rich source of B hadrons. The large acceptance in terms of rapidity and transverse momentum of the charged particle tracking system and the muon system make the upgraded Run II D0 detector an excellent tool for B physics. In this article, we report on selected physics results based on the first 250 pb^-1 of Run II data. This includes results on the X(3872) state, semileptonic B decays, B hadron lifetimes, flavour oscillations, and the rare decay B_s -> mu^+ mu^-.
Linear Convergence of the ADMM/Douglas-Rachford Algorithms for Piecewise Linear-Quadratic Functions and Application to Statistical Imaging
Timo Aspelmeier,C. Charitha,D. Russell Luke
Mathematics , 2015,
Abstract: We consider the problem of minimizing the sum of a convex, piecewise linear- quadratic function and a convex piecewise linear-quadratic function composed with an injective linear mapping. We show that, for such problems, iterates of the alternating directions method of multipliers converge linearly to fixed points from which the solution to the original problem can be computed. Our proof strategy uses duality and strong metric subregularity of the Douglas-Rachford fixed point mapping. Our analysis does not require strong convexity and yields error bounds to the set of model solutions. We demonstrate an application of this result to exact penalization for signal deconvolution and denoising with multiresolution statistical constraints.
Clustered Star Formation in W75 N
D. S. Shepherd,L. Testi,D. P. Stark
Physics , 2002, DOI: 10.1086/345743
Abstract: We present 2" to 7" resolution 3 mm continuum and CO(J=1-0) line emission and near infrared Ks, H2, and [FeII] images toward the massive star forming region W75 N. The CO emission uncovers a complex morphology of multiple, overlapping outflows. A total flow mass of greater than 255 Msun extends 3 pc from end-to-end and is being driven by at least four late to early-B protostars. More than 10% of the molecular cloud has been accelerated to high velocities by the molecular flows (> 5.2 km/s relative to v{LSR}) and the mechanical energy in the outflowing gas is roughly half the gravitational binding energy of the cloud. The W75 N cluster members represent a range of evolutionary stages, from stars with no apparent circumstellar material to deeply embedded protostars that are actively powering massive outflows. Nine cores of millimeter-wavelength emission highlight the locations of embedded protostars in W75 N. The total mass of gas & dust associated with the millimeter cores ranges from 340 Msun to 11 Msun. The infrared reflection nebula and shocked H2 emission have multiple peaks and extensions which, again, suggests the presence of several outflows. Diffuse H2 emission extends about 0.6 parsecs beyond the outer boundaries of the CO emission while the [FeII] emission is only detected close to the protostars. The infrared line emission morphology suggests that only slow, non-dissociative J-type shocks exist throughout the pc-scale outflows. Fast, dissociative shocks, common in jet-driven low-mass outflows, are absent in W75 N. Thus, the energetics of the outflows from the late to early B protostars in W75 N differ from their low-mass counterparts -- they do not appear to be simply scaled-up versions of low-mass outflows.
Properties of $z\sim3-6$ Lyman Break Galaxies. II. Impact of nebular emission at high redshift
S. de Barros,D. Schaerer,D. P. Stark
Physics , 2012, DOI: 10.1051/0004-6361/201220026
Abstract: We present a homogeneous, detailed analysis of the spectral energy distribution (SED) of $\sim$ 1700 LBGs from the GOODS-MUSIC catalogue with deep multi-wavelength photometry from $U$ band to 8 $\mu$m to determine stellar mass, age, dust attenuation, and star formation rate. Using our SED fitting tool, which takes into account nebular emission, we explore a wide parameter space. We also explore a set of different star formation histories. Nebular emission is found to significantly affect the determination of the physical parameters for the majority of $z \sim $ 3--6 LBGs. We identify two populations of galaxies by determining the importance of the contribution of emission lines to broadband fluxes. We find that $\sim$ $65\%$ of LBGs show detectable signs of emission lines, whereas $\sim$ $35\%$ show weak or no emission lines. This distribution is found over the entire redshift range. We interpret these groups as actively star forming and more quiescent LBGs, respectively. We find that it is necessary to considerer SED fits with very young ages ($<50$ Myr) to reproduce some colours affected by strong emission lines. Other arguments favouring episodic star formation and relatively short star formation timescales are also discussed. Considering nebular emission generally leads to a younger age, lower stellar mass, higher dust attenuation, higher star formation rate, and a large scatter in the SFR-$M_{\star}$ relation. Our analysis yields a trend of increasing specific star formation rate with redshift, as predicted by recent galaxy evolution models. The physical parameters of approximately two thirds of high redshift galaxies are significantly modified when we account for nebular emission. The SED models which include nebular emission shed new light on the properties of LBGs with numerous important implications.
Effect of Blast Furnace Sludge (BFS) Characteristics on Suitable Recycling Process Determining  [PDF]
Mamdouh Omran, Timo Fabritius, Timo Paananen
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2017, DOI: 10.4236/jmmce.2017.54016
Abstract: The present study aims to give a detailed characterization of blast furnace sludge (BFS) by using different techniques, in order to determine the most effective recycling method to recover valuable metals from this waste. BFS is composed mainly of hematite, as its iron-bearing phase, and carbon, in addition to fractions of silicate and carbonate materials. The studied BFS shows relatively high contents of iron (Fe) (390 g.kg-1), and carbon (C) (290 g.kg-1), due to abundance of hematite and coke, while the concentration of zinc (Zn) (2.5 g.kg-1) is low. The XRD analyses indicated that, hematite is more concentrated in the fine fraction (<20 μm), while the coarser fraction (90 - 250 μm) is dominated by calcite, quartz and X-ray amorphous coke. SEM-EDX analyses confirmed that particles rich in iron and zinc were detected in the fine fraction (<20 μm) of the sludge. Due to high Fe and C content in BFS, it can be utilized as self-reducing material and briquetting represent a potential method for recycling of blast furnace sludge.
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