24-h Temperature Research Articles

Combined Analysis to Characterize Yield Pattern of Greenhouse-grown Red Sweet Peppers

Understanding the irregular yield pattern of greenhouse-grown sweet peppers (Capsicum annuum L.) has been a challenge to researchers and greenhouse producers. Experimental data from 4 years, each consisting of 26 production weeks, were used in a time series analysis, neural network (NN) modeling, and regression analysis. Time series analysis revealed that weekly yield was influenced by yields from the preceding 2 weeks (Yd_1 and Yd_2), cumulative light 2 and 4 weeks prior (L_2 and L_4), and average 24-h air temperature 5 weeks prior (T_5). Cumulative light (L) data were transformed into kL by dividing by 1000 for subsequent NN modeling and regression analysis. These five inputs were used to establish a NN model, which illustrated the positive influence of Yd_1, kL_4, and kL_2 and negative influence of Yd_2 and T_5. Again, these five inputs were used in a regression analysis illustrating the positive influence of Yd_1 and the negative influence of Yd_2. Each input was further modified to include its squared value before entering the regression, which resulted in significant inputs of Yd_1, Yd_1 squared, and Yd_2 squared. Among these three analyses, the most consistent parameters were Yd_1 and Yd_2, confirming that the irregular yield pattern of greenhouse-grown peppers is of a biological nature. Environmental factors kL_2, kL_4, and T_5 did not show a consistent effect on yield in all three analyses, indicating yield pattern is less influenced by growing environment.

Effect of an intermediate bonding resin and flowable resin on the compatibility of two-step total etching adhesives with a self-curing composite resin

This study compared the effect of an activator, intermediate bonding resin and low-viscosity flowable resin on the microtensile bond strength of a self-curing composite resin used with two-step total etching adhesives. Twenty extracted permanent molars were used. The teeth were assigned randomly to nine groups (n=10) according to the adhesive system and application of additional methods (activator, intermediate adhesive, flowable resin). The bonding agents and additional applications of each group were applied to the dentin surfaces. Self-curing composite resin buildups were made for each tooth to form a core, 5mm in height. The restored teeth were then stored in distilled water at room temperature for 24h before sectioning. The microtensile bond strength of all specimens was examined. The data was analyzed statistically by one-way ANOVA and a Scheffe’ s test. The application of an intermediate bonding resin (Optibond FL adhesive) and low-viscosity flowable resin (Tetric N-flow) produced higher bond strength than that with the activator in all groups. Regardless of the method selected, Optibond solo plus produced the lowest μ TBS to dentin. The failure modes of the tested dentin bonding agents were mostly adhesive failure but there were some cases showed cohesive failure in the resin. [J Kor Acad Cons Dent 34(5):397-405, 2009]

Detailed energy saving performance analyses on thermal mass walls demonstrated in a zero energy house

An insulated concrete wall system 1 1 T-Mass™ by the Dow Chemical Company. was used on exterior walls of a zero energy house. Its thermal functions were investigated using actual data in comparison to a conventional wood frame system. The internal wall temperature of massive systems changes more slowly than the conventional wall constructions, leading to a more stable indoor temperature. The Energy10 simulated equivalent R-value and DBMS of the mass walls under actual climate conditions are, respectively, 6.98 (m 2 °C)/W and 3.39. However, the simulated heating energy use was much lower for the massive walls while the cooling load was a little higher. Further investigation on the heat flux indicates that the heat actually is transferred inside all day and night, which results in a higher cooling energy consumption. A one-dimensional model further verified these analyses, and the calculated results are in good agreement with the actual data. We conclude that the thermal mass wall does have the ability to store heat during the daytime and release it back at night, but in desert climates with high 24-h ambient temperature and intense sunlight, more heat will be stored than can be transferred back outside at night. As a result, an increased cooling energy will be required.

Effects of Production Parameters and Conditioning upon Ballistic Characteristics of Para Aramid Light Armors

Composite materials are increasingly used in armors design due to their high strength to weight ratios and energy absorption capacities. It is very important to determine the best production parameters for armor production. On the other hand, the armors must show superior durability against harsh working conditions. So it is crucial to know the ballistic characteristics of such composite armors. In this study the effect of production parameters upon the terminal ballistic properties of para-aramid composite armor were examined under different conditionings. The composite armor plates were produced by hot pressing with four different pressing times. Before ballistic test, the armor plates conditioned at +21, +63, and -35°C at 50% of relative humidity and +21°C immersed into water temperature for 24h, in which weapons, ammunition, and equipment designed for use in the battlefield, are expected to fully operate.

Neural network modelling to predict weekly yields of sweet peppers in a commercial greenhouse

The production of greenhouse-grown sweet pepper (Capsicum annuum L.) is irregular with a peak-and-valley pattern of weekly yields. We monitored the yields and environment in a commercial greenhouse in British Columbia over six (2000–2005) growing seasons. Light was defined as cumulative light over the current week, with L_1, L_2, L_3, L_4, L _ 5 and L_6 representing light over previous weeks. Temperature (AvgT) was defined as the current weekly average of 24-h air temperatures, with T_1, T_2 and T_3 representing temperatures over previous weeks. Inputs were also created for the current weekly yield (Y) and previous weekly yields (Y_1, Y_2, Y_3 and Y_4). Neural network (NN) modelling with up to 21 inputs was used to predict yields 1 wk (Y + 1) and 2 wk (Y + 2) in advance of the actual fruit harvest. Data for five different years were combined for model training with the year to be predicted held separate as a validation set. The best models used 13 inputs to predict Y + 1 with an average R2 of 0.66 over the 6 yr. Y_4, Y-Y_1, Y_1, L_1, Y, Y_3, Y-Y_3 and wk (of the year) were important inputs. The environmental inputs were of lesser importance, which suggests that the cyclic nature of pepper yields is inherent in the pepper biology. Predicting Y + 2 was more difficult with an average R2 of 0.59 over the 6 yr. NN have good potential for predicting pepper yields. Key words: Capsicum annuum L., flushing, fruit, greenhouse production, neural networks

Synthesis of Si-MCM-48 membrane by solvent extraction of the surfactant template

Mesoporous MCM-48 silica membranes have been synthesized on porous supports under hydrothermal conditions, using tetraethyl orthosilicate (TEOS) as silica source, cetyltrimethylammonium bromide (CTAB) as template surfactant. And then the templates were removed by solvent extraction instead of calcination. The results of the TG and FT-IR showed that the solvent of 1M HCl/EtOH solution was feasible to extract the templates in the MCM-48 materials and over 90% of the templates were extracted at room temperature for 24h. The results of XRD, SEM indicated that the MCM-48 membranes were prepared on the porous supports and extraction did not destroy the mesostructure of the MCM-48. The compactness of the extracted MCM-48 membrane was evaluated by the permeation of single gas (N2 and H2) with transmembrane pressure of 60–220kPa. The permeance of N2 was independent of the transmembrane pressure and the ideal separation factor was about 3.45. All the results demonstrate that the method, solvent extraction to remove surfactant template, is more effective to synthesize high quality MCM-48 membranes than calcination.

Antibrowning activity of MRPs in enzyme and fresh-cut apple slice models

The present study examined various types of Maillard reaction products (MRPs) for their inhibitory effect on mushroom tyrosinase. Results showed that monosaccharide–GSH (glutathione) but not polysaccharide–GSH derived MRPs were more active than GSH in inhibiting mushroom tyrosinase. However, in fresh-cut apple slice model, surprisingly GSH performed much better than sucrose–GSH derived MRPs when the apple slices were stored at room temperature for 24h. Further time-course study did find deterioration in tyrosinase mushroom inhibitory activity of sugar–GSH derived MRPs over time, suggesting the formed tyrosinase inhibitors in MRPs are unstable. Different combinations of chemical agents with sucrose–GSH derived MRPs were also investigated on apple slices. A synergistic effect was observed when sucrose–GSH derived MRPs (3.125mM) were applied in combination with 0.5% ascorbic acid. Apart from instability of principal inhibitors, observation of an unpleasant odor from apple slices treated with MRPs raised another concern about the probable negative impact of these inhibitors on the sensory quality of food products. Our research indicates the limited application of MRPs as antibrowning agents for food products.

The Use of Compressor Cycle Patterns: The Ability to Predict Freezer Failure

Biorepositories are tasked with the care and storage of priceless collections of biological specimens. Critical to the success of biorepository operations is the safe, secure, viable storage of the specimens entrusted to its care. The primary means by which this is accomplished is to ensure proper function of ultralow freezers. For a large biorepository this involves the tracking and monitoring of hundreds of freezers. Biorepository procedures typically require recording of the temperature of each freezer on a daily basis. At the Central Repository of the National Cancer Institute in Frederick, Maryland, temperature monitoring has been taken one step further. New procedures utilize the in-house 24-h temperature monitoring system to produce daily printouts of the fluctuation of temperature with time. These graphs are reviewed, and based upon an understanding of freezer compressor cycles are used to identify potential problems with freezer function. These new procedures, which can be used to predict failure, have identified specific types of temperature traces that are indicative of a failure rate 2.9 times greater than normal.

Osteoblastic Cell Differentiation on BMP-2 Pre-Adsorbed Octacalcium Phosphate and Hydroxyapatite

The present study was designed to investigate whether bone morphogenetic protein-2 (BMP-2) adsorbed onto octacalcium phosphate (OCP) and hydroxyapatite (HA) surfaces influences osteoblastic cell differentiation. Osteoblastic cell line, UAMS32, were cultured on plastic plate that was coated of synthetic OCP and HA. BMP-2 was pre-adsorbed on these calcium phosphates at 4°C or room temperature for 24h. The cells more proliferated on the BMP-2 pre-adsorbed OCP and HA than that of the controls (OCP and HA coating without BMP-2). ALP activities were higher on HA than on OCP when BMP-2 were pre-adsorbed at 4°C than at room temperature. The results suggest that pre-adsorption of BMP-2 in different temperature affects osteoblastic cell differentiation, most probably through different adsorption state of BMP-2 on this calcium phosphate.

Fever and sickness behavior during an opportunistic infection in a free-living antelope, the greater kudu (Tragelaphus strepsiceros)

To study their thermal responses to climatic stress, we implanted seven greater kudu (Tragelaphus strepsiceros) with intra-abdominal, brain, carotid, and subcutaneous temperature data loggers, as well as an activity logger. Each animal was also equipped with a collar holding a miniature black globe thermometer, which we used to assess thermoregulatory behavior. The kudu ranged freely within succulent thicket vegetation of the Eastern Cape Province, South Africa. The kudu spontaneously developed a bacterial pneumonia and consequent fever that lasted between 6 and 10 days. The fever was characterized by a significant increase in mean 24-h abdominal temperature from 38.9 +/- 0.2 degrees C to 40.2 +/- 0.4 degrees C (means +/- SD, t(6) = 11.01, P < 0.0001), although the amplitude of body temperature rhythm remained unchanged (t(6) = 1.18, P = 0.28). Six of the kudu chose warmer microclimates during the fever than when afebrile (P < 0.0001). Despite the selection of a warmer environment, on the first day of fever, the abdominal-subcutaneous temperature difference was significantly higher than on afebrile days (t(5) = 3.06, P = 0.028), indicating vasoconstriction. Some kudu displayed increased frequency of selective brain cooling during the fever, which would have inhibited evaporative heat loss and increased febrile body temperatures, without increasing the metabolic maintenance costs of high body temperatures. Average daily activity during the fever decreased to 60% of afebrile activity (t(6) = 3.46, P = 0.014). We therefore have recorded quantitative evidence for autonomic and behavioral fever, as well as sickness behavior, in the form of decreased activity, in a free-living ungulate species.

Feasibility and efficacy of a new non-invasive surface cooling device in post-resuscitation intensive care medicine

There is sufficient evidence that therapeutic hypothermia after non-traumatic cardiac arrest improves neurological outcome and reduces mortality. Many different invasive and non-invasive cooling devices are currently available. Our purpose was to show the efficacy, safety and feasibility using a non-invasive cooling device to control patient temperature within a range of 33-37 degrees C. A convenience sample of patients who have been resuscitated successfully from cardiac arrest and were intended for mild hypothermia therapy according to the guidelines and inclusion criteria were studied in a prospective observational case series at an emergency department of a tertiary care university hospital. The Medivance Arctic Sun System provides a new, non-invasive approach to reach a target temperature of 33 degrees C quickly, to maintain the target temperature for 24h, and then to actively re-warm at 0.4 degrees C/h to normothermia. Cooling was applied using the Arctic Sun in 27 patients. Data are presented as median and the interquartile range (25, 75%). Median age was 58 (49.5, 70) years. Time from cooling start to target temperature was 137 (96, 168)min, cooling rate was 1.2 degrees C/h (0.8, 1.5), stability of target temperature during hypothermia maintenance phase was satisfactory at 33.0 degrees C (32.9, 33.1), and duration of re-warming was 428 (394, 452)min. Using the Arctic Sun System in post-resuscitation care medicine for cooling cardiac arrest survivors is feasible and has proven to be highly effective in lowering patients' temperature rapidly without inducing skin irritations.

Development of Two Stages Cock's Semen Extender for Room Temperature Storage at Laboratory

A simple cock’s semen dilutor (two-stage) with minimum ingredients was developed in the present study. The stage-1dilutor was aimed to reduce the motility and metabolism during storage and the stage-2 dilutor was to be added just prior to insemination to revive the motility to facilitate the entry of spermatozoa into sperm host gland. Initially, the semen was diluted 1 : 1 with the stage-1 dilutor having lower pH that reduced the motility and metabolism. Subsequently, after 24h, the diluted semen was mixed slowly with another dilutor stage-2 at 1 : 2 ratios to revive the motility of the spermatozoa to normal level. Phosphate buffer was the base for both storage (stage-1) and recovery (stage-2) dilutors with a pH of 6.5 and 7.5, respectively. In stage-1 dilutor sodium glutamate to minimize metabolism of spermatozoa and antibiotics to check bacterial growth were used whereas these were absent in stage-2 dilutor. Glucose was added as energy source in the dilutor of both stages. The osmolarity of stage-1 and stage-2 dilutors was 346 and 327Osm/kg H20, respectively. This dilutor can be used to store the cock’s semen at room temperature (17-21°C) for 24h with sustained motility. This new approach for two-stage dilutor of cock’s semen storage at room temperature for extended period could be a useful A.I. tool under farm condition.

Prediction of Clouds and Rain Using a z-Coordinate Nonhydrostatic Model

Abstract The most common option for numerical models of the atmosphere is to use model layers following the surface of the earth, using a terrain-following vertical coordinate. The present paper investigates the forecast of clouds and precipitation using the z-coordinate nonhydrostatic version of the Lokalmodell (LM-z). This model uses model layers that are parallel to the surface of the sphere and consequently intersect the orography. Physical processes are computed on a special grid, allowing adequate grid spacing even over high mountains. In other respects the model is identical to the nonhydrostatic terrain-following version of the LM, which in a number of European countries is used for operational mesoscale forecasting. The terrain-following version of the LM (LM-tf) is used for comparison with the forecasts of the LM-z. Terrain-following coordinates are accurate when the orography is shallow and smooth, while z-coordinate models need not satisfy this condition. Because the condition of smooth orography is rarely satisfied in reality, z-coordinate models should lead to a better representation of the atmospheric flow near mountains and consequently to a better representation of fog, low stratus, and precipitation. A number of real-data cases, computed with a grid spacing of 7 and 14 km, are investigated. A total of 39 real-data cases have been used to evaluate forecast scores. A rather systematic improvement of precipitation forecasts resulted in a substantial increase of threat scores. Furthermore, RMS verification against radiosondes showed an improvement of the 24-h forecast, both for wind and temperature. To investigate the possibility of flow separation at mountain tops, the flow in the lee of southern Italy was investigated.

Effect of drying methods on essential oil content and composition of wormwood (Artemisia absinthium L.)

The aerial parts of wormwood (Artemisia absinthium L.) were harvested in full blooming stage in September 2005 from an area between Deylaman and Asiabar villages, around the Siahkal city in Gilan province in north of Iran. In order to complete drying, a sample of aerial parts was placed at shade (room temperature) for several days and a sample placed in ventilated oven at 35oC temperature for 24h. The aerial parts essential oil was extracted by hydrodistillation in a Clevenger apparatus and analyzed by GC/MS. Results showed that essential oil yields in shade condition and oven condition were 1.3 and 1.1 percent respectively. Also number of chemical components of the essential oil in shade drying and oven drying methods were 28 and 33 components respectively, which were mostly monoterpenes. β- pinene and β- thujone were main components of the both drying methods, which their contents in shade drying and oven drying methods were (23.8 and 18.6%) and (18.7 and 27.9%) respectively. Hydrocarbon monoterpenes content in shade drying method were higher than the other method but in case of oxygenated monoterpenes vice versa. There was not significant difference with respect to sesquiterpenes content between the drying methods. The results proved that chemo type of the studied wormwood essential oil was specific and different from other wormwood essential oil chemotypes, which have been reported.

Dietary tryptophan effects on plasma and salivary cortisol and meat quality in pigs1,2

Four experiments were conducted to determine the effects of supplemental Trp on meat quality, plasma and salivary cortisol, and plasma lactate. Experiment 1 was a preliminary study to measure plasma cortisol concentrations in 4 barrows (50 kg of BW) that were snared for 30 s at time 0 min. Pigs were bled at -60, -30, -15, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min. Plasma cortisol was near maximum 10 min after the pigs were snared. In Exp. 2, 20 barrows (50 kg of BW) were allotted to a basal corn-soybean meal diet or the basal diet with 0.5% supplemental l-Trp for 5 d. After the 5-d feeding period, pigs were snared for 30 s and bled at -10, 0, 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min after snaring. Pigs fed the diet with supplemental Trp had a lower (P < 0.01) mean plasma cortisol than pigs fed the basal diet. Plasma lactate also was decreased (P < 0.07) by supplemental Trp. In Exp. 3, the same pigs and treatments were used as in Exp. 2, but 5 pigs were snared and 15 pigs adjacent to those being snared were bled to determine if pigs are stressed when they are adjacent to pigs being snared. For pigs adjacent to snared pigs, the area under the curve (P < 0.06) and mean for plasma cortisol was lower (P < 0.01) in pigs fed Trp relative to those fed the basal diet. In Exp. 4, 90 barrows (initial BW of 106 kg) were allotted to 6 treatments in a 3 x 2 factorial arrangement. Three diets with Trp (basal diet, basal supplemented with 0.5% Trp for 5 d, or pigs fed the basal diet with a 0.1 g/kg of BW Trp bolus given 2 h before slaughter) were combined with 2 handling methods (minimal and normal handling). Dressing percent, 24-h pH, and 24-h temperature were reduced in the minimally handled pigs (P < 0.10) compared with the normally handled pigs. Pigs fed Trp in the diet relative to those fed the basal diet had increased 45-min temperature, Commission Internationale de l'Eclairage (CIE) redness (a*) and yellowness (b*) values, and drip and total losses (P < 0.10). Tryptophan in bolus form decreased 45-min pH in the minimally handled pigs but increased 45-min pH in the normally handled pigs (handling x Trp bolus interaction, P = 0.08). Tryptophan in the diet increased CIE lightness (L*) in minimally handled pigs but decreased CIE L* in the normally handled pigs (handling x Trp diet interaction, P = 06). No other response variables were affected by handling method or Trp. Results indicate that Trp decreases plasma cortisol but has no positive effect on meat quality.

On the Factors Controlling the Snow Surface and 2-m Air Temperatures Over the Arctic Sea Ice in Winter

Factors controlling the magnitudes of, and short-term variations in, the potential temperatures of the snow surface and the air at the height of 2 m θS and θ2 m over Arctic sea ice in winter are analysed. The study addresses the winters of 1986–1987 and 1987–1988, and is based on the temperature, wind, and cloud observations made by Russian drifting ice stations. It also relies on the ERA40 re-analyses of the European Centre for Medium-Range Weather Forecasts, which were utilised to calculate the lateral heat advection at the sites of the ice stations. The cloud cover and wind speed were more important than the heat advection in controlling the magnitudes of θ2 m and θS, while on a time scale of 24 h, during steady forcing conditions, the heat advection was the most important factor affecting the changes in θS and θ2 m. During changing conditions, and considering individual factors separately, the monthly mean 24-h temperature changes were less than ± 5 °C: the effect of the cloud cover was the largest, and that of the heat advection was the smallest. When simultaneous changes in the three factors were analysed, the seasonal mean temperature changes were even of the order of ±15 °C, with the strongest warming events exceeding 35 K in a single day. The difference θS − θ2 m reached its lowest seasonal mean values during conditions of clear skies (−1.3 °C), light winds (−1.3 °C) and warm-air advection (−0.8 °C). θS and θ2 m followed each other closely, even during major synoptic-scale temperature variations.

Estimating average daytime and daily temperature profiles within Europe

We present a methodology for estimating the average profiles of daytime and daily ambient temperature from a spatially-continuous database for any location within Europe. The primary database with 1-km grid resolution was developed by interpolation of monthly averages of 7 daily values of temperature: minimum and maximum and 5 measurements at 3-h intervals from 6:00 to 18:00 hours Greenwich Mean Time. With a little over 800 meteorological stations available, we obtained a cross-validation root mean square error of 1.0–1.2 °C, while the interpolation error is lower, at 0.5–0.7 °C. A polynomial fit was applied to estimate the daytime temperature profile (assuming only time from sunrise to sunset) from the interpolated 3-h measurements for each month. The curve fit coefficients make it possible to calculate a number of derived data, such as average daytime temperature, maximum daytime temperature and time of its occurrence within the region. An example demonstrates the coupling of the simulated daytime temperature profile with a model for assessing the relative efficiency of electricity generation by crystalline silicon photovoltaic modules. As an alternative to the polynomial fitting, a double-cosine method was applied to enable calculation of daily (24-h) temperature profiles for each month using interpolated minimum and maximum temperatures. Compared to the polynomial curve-fitting, this method does not offer lower errors, but it provides data which are more suitable for estimation of solar thermal heating or calculation of degree days for building heating/cooling.

The Combined Effects of Gulf Stream–Induced Baroclinicity and Upper-Level Vorticity on U.S. East Coast Extratropical Cyclogenesis

Abstract The Atlantic Surface Cyclone Intensification Index (ASCII) is a forecast index that quantifies the strength of low-level baroclinicity in the coastal region of the Carolinas. It is based on the gradient between the coldest 24-h average air temperature at Cape Hatteras and Wilmington, North Carolina, and the temperature at the western boundary of the Gulf Stream. The resulting prestorm baroclinic index (PSBI) is used to forecast the probability that a cyclone in the domain will exhibit rapid cyclogenesis. The initial ASCII study covered the years 1982–90. This dataset was recently expanded to cover the years 1991–2002, which doubled the number of cyclone events in the sample. These additional data provide similar position and slope of the linear regression fits to the previous values, and explain as much as 30% of the variance in cyclone deepening rate. Despite operational value, the neglect of upper-tropospheric forcing as a predictor in the original ASCII formulation precludes explanation of a large fraction of the deepening rate variance. Here, a modified index is derived in which an approximate measure of upper-level forcing is included. The 1991–2002 cyclone events were separated into bins of “strongly forced,” “moderately forced,” and “weakly forced” based on the strength of the nearest upstream maximum of 500-mb absolute vorticity associated with the surface low. This separation method reduced the scatter and further isolated the contributions of surface forcing versus upper-level forcing on extratropical cyclogenesis. Results of the combined upper-level index and surface PSBI demonstrate that as much as 74% of the deepening rate variance can be explained for cases with stronger upper-level forcing.

A non-invasive method for gastrointestinal parameter monitoring

To propose a new, non-invasive method for monitoring 24-h pressure, temperature and pH value in gastrointestinal tract. The authors developed a miniature, multi-functional gastrointestinal monitoring system, which comprises a set of indigestible biotelemetry capsules and a data recorder. The capsule, after ingested by patients, could measure pressure, temperature and pH value in the gastrointestinal tract and transmit the data to the data recorder outside the body through a 434 MHz radio frequency data link. After the capsule passed out from the body, the data saved in the recorder were downloaded to a workstation via a special software for further analysis and comparison. Clinical experiments showed that the biotelemetry capsules could be swallowed by volunteers without any difficulties. The data recorder could receive the radio frequency signals transmitted by the biotelemetry in the body. The biotelemetry capsule could pass out from the body without difficulties. No discomfort was reported by any volunteer during the experiment. In vivo pressure and temperature data were acquired. A non-invasive method for monitoring 24-h gastrointestinal parameters was proposed and tested by the authors. The feasibility and functionality of this method are verified by laboratory tests and clinical experiments.

Daily Mortality and Air Pollution in Atlanta: Two Years of Data from ARIES

Associations between daily mortality and air pollution were investigated in Fulton and DeKalb Counties, Georgia, for the 2-yr period beginning in August 1998, as part of the Aerosol Research and Inhalation Epidemiological Study (ARIES). Mortality data were obtained directly from county offices of vital records. Air quality data were obtained from a dedicated research site in central Atlanta; 15 separate air quality indicators (AQIs) were selected from the 70 particulate and gaseous air quality parameters archived in the ARIES ambient air quality database. Daily meteorological parameters, comprising 24-h average temperatures and dewpoints, were obtained from Atlanta's Hartsfield International Airport. Effects were estimated using Poisson regression with daily deaths as the response variable and time, meteorology, AQI, and days of the week as predictor variables. AQI variables entered the model in a linear fashion, while all other continuous predictor variables were smoothed via natural cubic splines using the generalized linear model (GLM) framework in S-PLUS. Knots were spaced either quarterly, monthly, or biweekly for temporal smoothing. A default model using monthly knots and AQIs averaged for lags 0 and 1 was postulated, with other models considered in sensitivity analyses. Lags up to 5 days were considered, and multipollutant models were evaluated, taking care to avoid overlapping (and thus collinear) AQIs. For this reason, PM2.5 was partitioned into its three major constituents: SO42−, carbon (EC + 1.4 OC), and the remainder; sulfate was assumed to be (NH4)2SO4 for this purpose. Initial AQI screening was based on all-cause (ICD-9 codes < 800) mortality for those aged 65 and over. For the (apparently) most important pollutants—PM2.5 and its 3 major constituents, coarse PM mass [CM], 1-h maximum CO, 8-h maximum O3—we investigated 15 mortality categories in detail. (The 15 categories result from three age groups [all ages, < 65, 65+] and five cause-of-death groups [all disease causes, cardiovascular, respiratory, cancer, and other “remainder” disease causes]). The GLM model outputs that were considered included mean AQI effects and their standard errors, and two indicators of relative model performance (deviance and deviance adjusted for the number of observations and model parameters). The latter indicator was considered to account for variations in the number of observations created by varying amounts of missing AQI data, which were not imputed. The single-AQI screening regressions on all-cause 65+ mortality show that CO, NO2, PM2.5, CM, SO2, and O3, followed by EC and OC, consistently have the best model fits, after adjusting for the number of observations. Their relative rankings, however, vary according to the smoothing knots used, and there is no correspondence between mean AQI effect and overall model fit. (Other regression runs often show that the best model fits are obtained with no AQI in the model.) There is no correspondence between mean AQI effect and statistical significance or between mean effect and serial correlation. There is a highly significant (.001 level) relationship between overall model fit and serial correlation; the best fitting models have the most frequent knot spacing and the most negative serial correlation. The regression analyses by cause of death find elderly circulatory deaths to be consistently associated with CO for all models.