Distributed QoS Guarantees for Realtime Traffic in Ad Hoc Networks

In this paper, we propose a new cross-layer framework, named QPART ( QoS br>rotocol for Adhoc Realtime Traffic), which provides QoS guarantees to real-time multimedia applications for wireless ad hoc networks. By adapting the contention window sizes at the MAC layer, QPART schedules packets of flows according to their unique QoS requirements. QPART implements priority-based admission control and conflict resolution to ensure that the requirements of admitted realtime flows is smaller than the network capacity. The novelty of QPART is that it is robust to mobility and variances in channel capacity and imposes no control message overhead on the network

Nonlinear Pricing on Private Roads with Congestion and Toll Collection Costs

Nonlinear pricing (a form of second-degree price discrimination) is widely used in transportation and other industries but it has been largely overlooked in the road-pricing literature. This paper explores the incentives for a profit-maximizing toll-road operator to adopt some simple nonlinear pricing schemes when there is congestion and collecting tolls is costly. Users are assumed to differ in their demands to use the road. Regardless of the severity of congestion, an access fee is always profitable to implement either as part of a two-part tariff or as an alternative to paying a toll. Use of access fees for profit maximization can increase or decrease welfare relative to usage-only pricing. Hence a ban on access fees could reduce welfare.congestion pricing; two-part pricing; private roads; toll collection costs

Time domain simulation of nonlinear acoustic beams generated by rectangular pistons with application to harmonic imaging

This is the published version. Copyright 2005 Acoustical Society of AmericaA time-domain numerical code (the so-called Texas code) that solves the Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation has been extended from an axis-symmetric coordinate system to a three-dimensional (3D) Cartesian coordinate system. The code accounts for diffraction (in the parabolic approximation), nonlinearity and absorption and dispersion associated with thermoviscous and relaxation processes. The 3D time domain code was shown to be in agreement with benchmark solutions for circular and rectangular sources, focused and unfocused beams, and linear and nonlinear propagation. The 3D code was used to model the nonlinear propagation of diagnosticultrasound pulses through tissue. The prediction of the second-harmonic field was sensitive to the choice of frequency-dependent absorption: a frequency squared f2 dependence produced a second-harmonic field which peaked closer to the transducer and had a lower amplitude than that computed for an f1.1 dependence. In comparing spatial maps of the harmonics we found that the second harmonic had dramatically reduced amplitude in the near field and also lower amplitude side lobes in the focal region than the fundamental. These findings were consistent for both uniform and apodized sources and could be contributing factors in the improved imaging reported with clinical scanners using tissue harmonic imaging

Vegetation Mapping of Mammoth Cave National Park using Multi-date Landsat-8 Imagery and Lidar data

Up-to-date and detailed vegetation map provides critical information for habitat management. In addition, a vegetation map is necessary for the Park’s Fire Management, for classification of fuel types, and for delineation of fire management units. There have been several attempts of vegetation mapping in 1934, 1975 and 1997. Recent advancements in mapping technology and the availability of high resolution Lidar data call for a new vegetation map for the Park’s management team. In this study, Landsat-8 Operational Land Imager (OLI) imagery, Lidar and geology dataset were applied to vegetation mapping. Habitat types are determined by a combination of geology, aspect and slope. Coniferous and deciduous trees are distinguished using multi-date Landsat-8 imagery through image classification and NDVI analysis. Habitat type and physical properties derived from Lidar data will be applied to identify specific vegetation species. The research will produce a new vegetation map and a habitat map for the Mammoth Cave National Park. The maps will provide critical information for habitat and fire management. The research method integrating Lidar and Landsat-8 data in digital vegetation and habitat mapping will be valuable for similar projects at other locations

Customer Satisfaction and Behavioral Intentions: The Case of Aruba-- Small Island Nation

Tourism studies related to small island destinations have become a research stream amongst many academics in recent years. The current study investigates tourist satisfaction related to a tour operator on the island of Aruba that specializes in jeep and bus tours. As there is an increased expenditure pattern for these types of activities, companies are looking for ways to improve customer satisfaction and behavioral intentions. Results indicate that tourists are generally satisfied with the tour company; however a difference in satisfaction ratings was obtained for respondents 61 years old or above. Four factors were extracted from tourists’ satisfaction attributes and three of these factors, including the overall tour value, tour guide, and sound systems used during these tours, were found to be strong predictors of behavioral intentions measured by the likelihood to rebook and the likelihood to recommend the tour company to family and friends. Operational and marketing strategies were suggested based on the findings of the study

Radiation therapy combined with intracerebral administration of carboplatin for the treatment of brain tumors

Background: In this study we determined if treatment combining radiation therapy (RT) with intracerebral (i.c.) administration of carboplatin to F98 glioma bearing rats could improve survival over that previously reported by us with a 15 Gy dose (5 Gy × 3) of 6 MV photons.Methods: First, in order to reduce tumor interstitial pressure, a biodistribution study was carried out to determine if pretreatment with dexamethasone alone or in combination with mannitol and furosemide (DMF) would increase carboplatin uptake following convection enhanced delivery (CED). Next, therapy studies were carried out in rats that had received carboplatin either by CED over 30 min (20 μg) or by Alzet pumps over 7 d (84 μg), followed by RT using a LINAC to deliver either 20 Gy (5 Gy × 4) or 15 Gy (7.5 Gy × 2) dose at 6 or 24 hrs after drug administration. Finally, a study was carried out to determine if efficacy could be improved by decreasing the time interval between drug administration and RT.Results: Tumor carboplatin values for D and DMF-treated rats were 9.4 ±4.4 and 12.4 ±3.2 μg/g, respectively, which were not significantly different (P = 0.14). The best survival data were obtained by combining pump delivery with 5 Gy × 4 of X-irradiation with a mean survival time (MST) of 107.7 d and a 43% cure rate vs. 83.6 d with CED vs. 30-35 d for RT alone and 24.6 d for untreated controls. Treatment-related mortality was observed when RT was initiated 6 h after CED of carboplatin and RT was started 7 d after tumor implantation. Dividing carboplatin into two 10 μg doses and RT into two 7.5 Gy fractions, administered 24 hrs later, yielded survival data (MST 82.1 d with a 25% cure rate) equivalent to that previously reported with 5 Gy × 3 and 20 μg of carboplatin.Conclusions: Although the best survival data were obtained by pump delivery, CED was highly effective in combination with 20 Gy, or as previously reported, 15 Gy, and the latter would be preferable since it would produce less late tissue effects.peer-reviewe

The Way to Spray: Modeling Nasal Spray Deposition

Intranasal drug delivery is an alternative method in addition to traditional oral and intravenous doses. Nasal drug delivery has proven to be a very effective technique for nicotine cessation (Hjalmarson et al., 1994), the influenza vaccine (Jackson et al. 1999), and drugs that need to be take continuously, such as insulin (Dondeti et al., 1995). Studies have found that for effective fast-acting body response, the drug needs to be deposited in the highly vascularized mucosal tissue lining the bony turbinates in the nasal cavity. Commercial nasal sprays are continuously optimizing parameters to develop the most effective deposition patterns. In this project, drug deposition is modeled using a simplified 2D depiction of the nasal passageway with uniformly-shaped, spherical spray particles. This problem is implemented in COMSOL by using 2D Navier Stokes fluid flow equations to model the airflow through the nose, and the Particle Tracing module to model the spray trajectory and deposition. The model output was validated by determining the percentages of particles in each region of the nasal passage - anterior, turbinate, posterior, and outlet - and comparing with published experimental data by Cheng et al (2001). A sensitivity analysis was done on the following parameters: particle density, particle size, nozzle spray angle, and nozzle penetration depth. It was found that this model was sensitive to only penetration depth. As penetration depth through the nostril increased, there was a decrease in the particle deposition in the anterior region of the nasal cavity and an increase in the percentage of particles that exited through the outlet. Deposition in the middle and posterior regions was not affected by variation in penetration depth. Our sensitivity analysis demonstrated that variations in spray angle, particle size, and density of the nasal spray fluid do not significantly affect deposition pattern. Therefore, when designing nasal sprays, as long as these parameters remain within the specified ranges, consistent deposition patterns will be achieved. This result also allows for further research on creating sprays that are more concentrated and have encapsulated drugs

Expression of glypican 3 in placental site trophoblastic tumor

<p>Abstract</p> <p>Background</p> <p>Glypican-3 (GPC3) is a membrane-bound heparan sulfate proteoglycan that functions in embryonic cell growth and differentiation and is highly expressed in the placenta. GPC3 is mutated in Simpson-Golabi-Behmel syndrome, which is characterized by tissue overgrowth and an increased risk of embryonal malignancies. GPC3 has also been implicated in sporadic cancer, particularly hepatocellular carcinoma, for which it has been shown to be a useful diagnostic marker. Although GPC3 expression has been studied in non-neoplastic placental tissue, its presence in gestational trophoblastic diseases has not been previously explored. The purpose of this study was to investigate the immunohistochemical expression of GPC3 in placental site trophoblastic tumor (PSTT), a very rare gestational trophoblastic neoplasm which may be morphologically confused with non-trophoblastic tumors, and to assess its possible utility as a diagnostic marker.</p> <p>Methods</p> <p>Fifteen cases of PSTT, as well as samples from placental site nodule (PSN) (n = 2), leiomyosarcoma (n = 1), leiomyoma (n = 1), invasive cervical squamous cell carcinoma (n = 7) and endometrial adenocarcinoma (n = 11) were examined. Immunoreactivity was semi-quantitatively evaluated as negative (0, < 5% of cells stained), focally positive (1+, 5-10% of cells stained), positive (2+, 11-50% of cells stained) or diffusely positive (3+, > 50% of cells stained). Staining intensity for each subtype was graded from 0 to 3 and a mean intensity was calculated.</p> <p>Results</p> <p>Eighty percent of PSTT (12/15) were immunoreactive for GPC3 (0, 20; 1+, 20%; 2+, 40%; 3+, 20%) with a mean intensity of 1.3. Stronger, predominately cytoplasmic staining was seen in larger multi- and mononucleated cells with smaller mononucleate cells showing weak muddy cytoplasmic staining. Both PSN cases were positive (1+, 50%; 2+, 50%) and two of nine invasive cervical squamous cell carcinomas showed staining (0, 57%; 1+, 29%; 2+, 14%), predominately in a basal distribution. Other uterine tumors and non-neoplastic tissues were negative.</p> <p>Conclusions</p> <p>Identification of GPC3 in PSTT and PSN is consistent with the derivation of these lesions from intermediate trophoblasts, which have been described to express GPC3. GPC3 may be a useful adjunct immunohistochemical marker in differentiating PSTT from non-trophoblastic tumors.</p

Deposit Insurance and Discretion in Loan Loss Provisioning

Deposit insurance (DI) shifts claims on bank liabilities from depositors to the insurer. It also induces moral hazard, leading banks to take more risks. Both forces affect stakeholder incentives and, consequently, should influence bank accounting. This paper studies how a recent, substantial expansion in DI coverage impacts a key accounting policy: discretion in banks’ loan loss provision (LLP). We compare affected and exogenously unaffected banks using propensity-score-matched difference-in-differences. Banks that experience an increased DI ceiling post more positive discretionary LLP, suggesting a capital-reducing or conservative bent. Results are strongest for banks most exposed to the shock, those subject to the most regulatory scrutiny, and those that increase risk most. Our findings are consistent with regulatory pressure to recognize losses proactively, suggesting regulatory preferences shape financial reporting. We are the first to estimate how DI impacts bank accounting