Locally Adaptive Products for Genuine Spherical Harmonic Lighting

Precomputed radiance transfer techniques have been broadly used for supporting complex illumination effects on diffuse and glossy objects. Although working with the wavelet domain is efficient in handling all-frequency illumination, the spherical harmonics domain is more convenient for interactively changing lights and views on the fly due to the rotational invariant nature of the spherical harmonic domain. For interactive lighting, however, the number of coefficients must be limited and the high orders of coefficients have to be eliminated. Therefore spherical harmonic lighting has been preferred and practiced only for interactive soft-diffuse lighting. In this paper, we propose a simple but practical filtering solution using locally adaptive products of high-order harmonic coefficients within the genuine spherical harmonic lighting framework. Our approach works out on the fly in two folds. We first conduct multi-level filtering on vertices in order to determine regions of interests, where the high orders of harmonics are necessary for high frequency lighting. The initially determined regions of interests are then refined through filling in the incomplete regions by traveling the neighboring vertices. Even not relying on graphics hardware, the proposed method allows to compute high order products of spherical harmonic lighting for both diffuse and specular lighting

Local Hall effect in hybrid ferromagnetic/semiconductor devices

We have investigated the magnetoresistance of ferromagnet-semiconductor devices in an InAs two-dimensional electron gas system in which the magnetic field has a sinusoidal profile. The magnetoresistance of our device is large. The longitudinal resistance has an additional contribution which is odd in applied magnetic field. It becomes even negative at low temperature where the transport is ballistic. Based on the numerical analysis, we confirmed that our data can be explained in terms of the local Hall effect due to the profile of negative and positive field regions. This device may be useful for future spintronic applications.Comment: 4 pages with 4 fugures. Accepted for publication in Applied Physics Letter

Technical efficiency of small-scale honey producers in Ethiopia: A stochastic frontier analysis

In this paper, a study is presented of the dynamic behavior of an automatic transmit power control (ATPC) loop in a single fixed wireless system (FWS) link subject to multipath fading and an uncorrelated co-channel interferer that does not use ATPC (this represents a so-called non-ATPC FWS link or a fixed satellite link). Fundamental questions include the sensitivity of an ATPC link to multipath interference and the co-channel interference that may be caused by a non-ATPC interferer. In the context of the present project, a good example of a non-ATPC interferer is a fixed satellite to which one antenna in a fixed microwave link has partial view. A computer model was developed that constitutes a useful tool in describing; simulating and analyzing an ATPC loop in a single FWS link. With the aid of this model, results are presented on the sensitivity of an ATPC loop in a FWS link with respect to channel conditions, non-ATPC interference and parameter settings

Inhaled corticosteroids and risk of pneumonia in newly diagnosed COPD

SummaryIntroductionThe use of inhaled corticosteroids (ICS) in COPD may be associated with an increased risk of pneumonia. Little is known of this risk in newly diagnosed COPD patients. The objective of this study was to determine if the use of ICS among newly diagnosed COPD patients is associated with an increased risk of pneumonia hospitalizations.MethodsUsing data from the Department of Veterans Affairs and Centers for Medicare and Medicaid Services, a nested case–control study was performed. We identified patients 65 years of age or older with a new diagnosis of COPD from 1998 to 2002. A total of 145,586 patients were identified. Cases were defined based on hospitalization for pneumonia and exposure was prior use of ICS. Up to 10 controls were matched for each case based on age, sex, month and year of the case. The association between ICS use and pneumonia was evaluated with conditional logistic regression controlling for age, comorbidities, medication classes associated with the risk of pneumonia, and markers of COPD severity.ResultsThere were 13,995 cases of pneumonia. The cohort was predominantly male with an average age of 75.1 (SD=5.4) years. The rate of pneumonia was 6.4 per 100 person-years. After adjustment for covariates, patients with current use of ICS were 1.38 (95% CI, 1.31–1.45) times more likely to have a hospitalization for pneumonia than those without current use of ICS.ConclusionsThe use of ICS among patients with newly diagnosed COPD is associated with an increased risk of hospitalization for pneumonia