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A study was designed to determine the effect of feeding yeast cell wall (YCW) on performance of newly received crossbred heifers (n = 140; 225 ± 9.4 kg). Heifers were sorted by source (n = 2) and arranged in a completely randomized block design (35 pens; 7 pens per treatment; 4 heifers per pen). Heifers were separated into treatments [control (CON), YCW A (2.5 g/d per head), YCW AA (5.0 g/d per head), YCW B (2.5 g/d per head), or YCW C (2.5 g/d per head)] and fed for 56 d. Daily DMI and individual BW (every 14 d) were collected. On d 56, cattle from treatments CON, YCW A, and YCW C (21 pens; 7 pens per treatment; 4 heifers per pen) were fitted with vaginal temperature (VT) recording devices. On d 63 cattle were weighed and challenged with a s.c. dose (0.5 μg/kg of BW) of lipopolysaccharide (LPS). A final BW was collected and VT devices were removed after 14 d. A significant source × treatment interaction was detected, and data were separated accordingly. In source 1, YCW C heifers exhibited greater BW at d 42 and ADG from 0 to 42 d compared with all other treatments (P = 0.02 and P 0.62). There was an increase in VT in all treatments after LPS (P

The objectives were to evaluate the interaction of ractopamine hydrochloride (Optaflexx, OPT) and terminal implant (TI) on growth performance, carcass characteristics, and meat quality of finishing beef heifers. A 3 × 2 factorial randomized complete block design was used with 2 levels of OPT and 3 durations of TI. British × Continental heifers (n = 216; 341.6 kg) were blocked by BW and randomly allotted to 54 pens (9 pens per treatment; 6 pens per block; 4 heifers per pen). The main treatment effects were implant [TE-200 with Tylan (tylosin phosphate; 200 mg of trenbolone acetate + 24 mg of estradiol-17β) administered 140, 100, or 60 d from slaughter] and OPT (0 or 200 mg per head per day). No implant × OPT interactions were detected, so only main effects are reported. Average daily gain (0.14 kg difference), predicted carcass ADG (0.24 kg difference), and HCW (5.6 kg difference) were increased (P 0.10) in Warner-Bratzler shear force were detected at d 3, 7, and 21 aging postmortem, although the shear force values of the OPT steaks at d 14 were higher (0.45 kg; P < 0.05). Results from this experiment demonstrated that OPT, when fed to heifers, increased ADG, calculated carcass ADG, and HCW with minimal effect on carcass quality. Furthermore, this experiment indicated that the duration of the TI window did not affect overall performance, final BW, or carcass quality.

English × Continental heifers ( = 180) were sourced in 2 loads (219.3 ± 16.0 and 221.4 ± 16.4 kg, respectively) from commercial auction barns to study the effects of feeding dehydrated citrus pulp (DCP) on feedlot performance of newly received heifers. A completely randomized block design was used with BW nested within arrival load and blocked by BW into 3 dietary treatments (36 pens, 5 heifers/pen, 12 blocks, 3 pens/block, and 12 pens/treatment). Treatment diets contained 1) 0% DCP (control diet [CON]), 2) 10% DCP, or 3) 20% DCP on a DM basis. Diets containing DCP were exchanged with steam-flaked corn on a 1:1 basis. Cattle were fed a 63, 73, and 83% concentrate diet from d 0 to 28, d 28 to 42, and d 42 to 56, respectively. Over the 56-d trial period, as the amount of dietary DCP increased, DMI decreased ( = 0.01), ADG decreased ( < 0.01), and G:F decreased ( = 0.02). From d 0 to 28, there was no difference in the observed minus the predicted NEg of the diet ( = 0.73); from d 28 to 42, there was a linear increase in NEg favoring DCP treatments ( < 0.01); and from d 42 to 56, there was a linear decrease in NEg against the DCP treatments ( < 0.01). At the conclusion of the trial, a subset of heifers ( = 22; 307.89 ± 3.32 kg on d 63) were used to evaluate blood metabolite concentrations before and after a lipopolysaccharide (LPS) challenge. On d 63, heifers were fitted with jugular catheters and moved into individual stalls. On d 64, heifers were intravenously challenged with LPS (0.5 μg/kg BW), and blood samples were collected every 0.5 h from -2 to 8 h and at 24 h relative to the LPS challenge (0 h). Serum glucose, serum urea nitrogen (SUN), and NEFA concentrations were determined. Cattle lost less weight at both 24 and 72 h after the LPS challenge with increasing DCP percentage ( < 0.01). Glucose ( = 0.12) and NEFA ( = 0.13) concentrations did not differ before the LPS challenge; however, there was a treatment effect for SUN, with elevated concentrations of SUN in CON cattle ( < 0.01). After the LPS challenge, DCP-fed cattle had reduced glucose, elevated NEFA, and reduced SUN concentrations ( ≤ 0.01). Results indicate that dietary DCP modulated metabolite concentrations in heifers following an endotoxin challenge and affected feedlot performance when incorporated in receiving diets in replacement of corn. Future studies will need to address strategies to increase DMI or explore levels of DCP less than 10% in the diet of newly received heifer calves.

The objective of this experiment was to determine the effect of yeast supplementation on the performance and health of newly weaned receiving cattle. Weaned crossbred steers (n = 184; initial BW = 203 ± 1 kg) were blocked by BW and randomly assigned to pen (4 pens/block; 5 to 6 animal/pen). Pens within a block were assigned randomly to 1 of 4 treatments (9 pens/treatment): 1) control (CON; no yeast); 2) live yeast (LY; 5 g/d per animal live yeast), 3) yeast cell wall (YCW; 5 g/d per animal yeast cell wall); 4) LY + YCW (5 g/d per animal LY and 5 g/d per animal YCW). Daily DMI was recorded and individual BW was collected every 14 d for 56 d. Data were analyzed using a randomized complete block design with the fixed effect of treatment and random effect of block. A subset of 24 steers (n = 6/treatment) was used on d 38 for a lipopolysaccharide challenge. Calves were fitted with jugular catheters and indwelling rectal-temperature measuring devices that measured rectal temperature. Cumulative DMI increased (P = 0.05) for the LY, YCW, and LY + YCW treatments compared with CON (6.02, 5.96, 5.89, and 5.47, kg/d, respectively). Before lipopolysaccharide challenge, CON calves had higher rectal temperature compared with LY + YCW (P ≤ 0.01) and LY (P ≤ 0.04) calves. Peak cortisol concentrations after lipopolysaccharide challenge were 26.5 ng/mL greater (P ≤ 0.04) in CON calves compared with LY + YCW calves. Results indicate that yeast supplements increased DMI and could improve cattle health during the receiving period.

This study examined the effect of feeding yeast cell wall (YCW) products on the metabolic responses of newly-received feedlot cattle to an endotoxin challenge. Heifers were separated into treatment groups receiving either a Control diet, YCW-A or YCW-C, and were fed for 52 d. Heifers were weighed on d 0, 14, 36, 38 and 52. On d 37 heifers were challenged i.v. with LPS [0.5 µg/kg body weight (BW)] and blood samples were collected relative to LPS challenge. Heifer BW increased from d 0 to 36 and from d 38 to 52, but was not affected by treatment. Post-LPS, glucose concentrations increased and were less in YCW-A than Control and YCW-C heifers. Pre-LPS, insulin concentrations were greater in YCW-A and YCW-C than Control heifers. Post-LPS, insulin concentrations increased with YCW-C having greater insulin than Control heifers. Pre-LPS, NEFA concentrations tended to be less in YCW-C than Control heifers. Post-LPS non-esterified fatty acids (NEFA) concentrations were less in YCW-C than Control and YCW-A heifers. Post-LPS, blood urea nitrogen (BUN) concentrations were greater in YCW-A than Control and YCW-C. These data indicate, based on NEFA and BUN data, that certain YCW products can enhance energy metabolism during an immune challenge without causing lipolysis or muscle catabolism.

A study was conducted to determine the effect of feeding yeast cell wall (YCW) products on the physiological and acute phase responses of crossbred, newly-received feedlot heifers to an endotoxin challenge. Heifers ( n = 24; 219 ± 2.4 kg) were separated into treatment groups receiving either a control diet ( n = 8), YCW-A (2.5 g/heifer/d; n = 8) or YCW-C (2.5 g/heifer/d; n = 8) and were fed for 52 d. On d 37 heifers were challenged i.v. with LPS (0.5 µg/kg body mass) and blood samples were collected from −2 h to 8 h and again at 24 h relative to LPS challenge. There was an increase in vaginal temperature in all heifers post-LPS, with YCW-C maintaining a lower vaginal temperature post-LPS than control and YCW-A heifers. Sickness behavior scores increased post-LPS in all heifers, but were not affected by treatment. Cortisol concentrations were greatest in control heifers post-LPS compared with YCW-A or YCW-C heifers. Concentrations of IFN-γ and TNF-α increased post-LPS, but were not affected by treatment. Serum IL-6 concentrations increased post-LPS and were greater in control heifers than YCW-A and YCW-C heifers. These data indicate that YCW supplementation can decrease the physiological and acute phase responses of newly-received heifers following an endotoxin challenge.

Crossbred steers (n = 20; 235 ± 4 kg) were fed for 53 d during a receiving period to determine if supplementing chromium (Cr; KemTRACE Chromium Propionate 0.04%, Kemin Industries, Des Moines, IA) would alter glucose or lipid metabolism of newly received cattle. Chromium premixes were supplemented to add 0 (Con) or 0.2 mg/kg of Cr to the total diet on a DM basis. Cattle were fi tted with jugular catheters on d 52. A glucose tolerance test (GTT) and an insulin sensitivity test (IST) were conducted on d 53. Blood samples were collected from -60 to 150 min relative to each infusion. Serum was isolated to determine glucose, insulin, and NEFA concentrations. Throughout GTT, no differences were detected in glucose concentrations, glucose clearance rates (k), or preinfusion insulin concentrations (P > 0.50), but insulin concentrations postinfusion tended (P = 0.06) to be greater for the Cr-supplemented steers. This caused an increase in the insulin to glucose ratio (I:G) from 0 to 150 min postinfusion for the Cr-supplemented steers (P = 0.03). In addition, NEFA concentrations during GTT were lower (P ≤ 0.01) for Cr-supplemented steers both preinfusion and postinfusion. During IST, there was no treatment effect on glucose concentrations preinfusion (P = 0.38), but postinfusion glucose concentrations were greater (P 0.33). The I:G were not affected by treatment (P > 0.40).Concentrations of NEFA were reduced (P < 0.01) both preinfusion and postinfusion during IST for Cr-supplemented steers. Results of this study indicate that supplementation of Cr can signifi cantly alter lipid metabolism. This suggests that these steers had less dependence on lipid metabolism for energy or sensitivity of adipose tissue to antilipolytic signals was reduced. Results of glucose and insulin metabolism were inconsistently modifi ed after a GTT and an IST.

Crossbred steers (n = 180; 230 ± 6 kg) were fed during a 56-d receiving period to determine if supplementing chromium (Cr; KemTRACE Chromium Propionate 0.04%, Kemin Industries) would improve feedlot performance and health of newly-received cattle. A completely randomized block design (36 pens; 9 pens/treatment; 5 steers/pen) was used. Chromium premixes were supplemented to add 0 (Con), 0.1, 0.2, or 0.3 mg/kg of Cr to the total diet on a DM basis. No differences were detected on d 0 or after the first 14 d on feed. From d 0 to d 28, DMI (P = 0.07) and ADG increased linearly (P = 0.04) as Cr concentrations increased. From d 0 to d 56, BW (P = 0.08) displayed a tendency to increase linearly, and consequently ADG and G:F increased linearly (P ≤ 0.05) as Cr concentrations increased. The number of steers treated at least once for respiratory symptoms tended (P = 0.07) to linearly decrease as Cr concentrations increased. Twenty additional steers (235 ± 4 kg) were fed 56 d to determine if supplementing Cr (Con or 0.2 mg/kg Cr) would alter the metabolic response of newly-received cattle to a lipopolysaccharide (LPS) challenge. Cattle were fitted with jugular catheters on d 52. On d 55, blood samples were collected at 0.5-h intervals from -2 to 8 h, and again at 24 h relative to a LPS challenge (0.5 μg/kg BW) at 0 h. Serum glucose, insulin, and NEFA concentrations were determined from blood samples. Steer BW was also measured at cannulation, and 24 h and 8 d post-LPS. Steer BW did not differ at cannulation (P = 0.37), but 24 h post-LPS, Cr-supplemented steers had lost less BW (P = 0.03). Pre-LPS glucose concentration did not differ (P = 0.97). Post-LPS, there was a time × treatment interaction (P 0.13). Concentration of NEFA did not differ pre-LPS (P = 0.54); but 0.5 h post-LPS Cr-treated steers produced a greater peak NEFA concentration (P < 0.04). Results of this study indicate that supplementation of Cr to the basal diet can have beneficial effects on the performance and health of newly-received steers. These data also suggest that supplementation of Cr attenuated BW loss and allowed for a quicker recovery after a LPS challenge.

Airborne contaminant transport in cities presents challenging new requirements for computational fluid dynamics. The unsteady flow involves very complex geometry and insufficiently characterized boundary conditions, and yet the challenging and timely nature of the overall problem demands that the turbulence be included efficiently with an absolute minimum of extra memory and computing time requirements. This paper describes the monotone integrated large eddy simulation methodology used in NRL’s FAST3D-CT (CT is contaminant transport) simulation model for urban CT and focuses on critical validation issues that need to be addressed to achieve practical predictability. Progress in validation studies benchmarking with flow data from wind-tunnel urban model simulations and actual urban field studies are reported. Despite inherent physical uncertainties and current model tradeoffs, it is clearly possible to achieve some degree of reliable prediction.

This paper quantitatively assesses the spatial extent of modeled contaminated regions resulting from hypothetical airborne agent releases in major urban areas. We compare statistics from a release at several different sites in Washington DC and Chicago using a Gaussian puff model (SCIPUFF, version 1.3, with urban parameter settings) and a building-resolving computational fluid dynamics (CFD) model (FAST3D-CT). For a neutrally buoyant gas source term with urban meteorology, we compare near-surface dosage values within several kilometers of the release during the first half hour, before the gas is dispersed beyond the critical lethal level. In particular, using “fine-grain” point-wise statistics such as fractional bias, spatial correlations and the percentage of points lying within a factor of two, we find that dosage distributions from the Gaussian puff and CFD model share few features in common. Yet the “coarse-grain” statistic that compares areas contained within a given contour level reveals that the differences between the models are less pronounced. Most significant among these distinctions is the rapid lofting, leading to enhanced vertical mixing, and projection downwind of the contaminant by the interaction of the winds with the urban landscape in the CFD model. This model-to-model discrepancy is partially ameliorated by supplying the puff model with more detailed information about the urban boundary layer that evolves on the CFD grid. While improving the correspondence of the models when using the “coarse-grain” statistic, the additional information does not lead to quite as substantial an overall agreement between the models when the “fine-grain” statistics are compared. The taller, denser and more variable building landscape of Chicago created increased sensitivity to release site and led to greater divergence in FAST3D-CT and SCIPUFF results relative to the flatter, sparser and more uniform urban morphology of Washington DC.

Background: Patients treated with total knee arthroplasty are at high risk for the development of venous thromboembolism postoperatively. This study compared the efficacy and safety of two common thromboprophylactic agents, enoxaparin (a low‐molecular-weight heparin) and warfarin. Methods: Three hundred and forty‐nine patients were included in a prospective, randomized, multicenter, open-label, parallel-group clinical trial. Treatment with enoxaparin (30 mg, administered subcutaneously twice daily) or warfarin (adjusted to an international normalized ratio of 2 to 3) was initiated during the immediate postoperative period, within eight hours after the surgery, and was continued for four to fourteen days. Venous thromboembolism was defined as deep‐vein thrombosis documented by contrast venography, symptomatic deep‐vein thrombosis documented by lower-extremity ultrasonography, or symptomatic pulmonary embolism confirmed by a positive lung scan or pulmonary angiography. Results: In the all‐treated-patients group, eighty (45%) of the 176 warfarin‐treated patients had venous thromboembolism: fifty‐nine (34%) had distal deep‐vein thrombosis; twenty (11%), proximal deep‐vein thrombosis; and one (0.6%), pulmonary embolism. Venous thromboembolism developed in significantly fewer (p = 0.0001) enoxaparin‐treated patients (forty-four of 173; 25%): forty‐one (24%) had distal deep‐vein thrombosis, three (2%) had proximal deep‐vein thrombosis, and none had pulmonary embolism. The enoxaparin‐treated patients also had a significantly lower prevalence of proximal deep‐vein thrombosis (p = 0.002). The estimated odds for the development of venous thromboembolism were 2.52 times greater (95% confidence interval, 2.00 to 3.19) with warfarin than they were with enoxaparin. Major hemorrhage occurred in four warfarin‐treated patients and nine enoxaparin‐treated patients; with the numbers available, this difference was not significant (p = 0.17). Clinically important operative‐site hemorrhage occurred in six (3%) of the warfarin-treated patients and twelve (7%) of the enoxaparin-treated patients (p = 0.15). Conclusions: A fixed 30-mg subcutaneous dose of enoxaparin, administered twice daily, with the first dose administered within eight hours after the completion of surgery, was significantly more effective than adjusted‐dose warfarin in reducing the occurrence of asymptomatic venous thromboembolism, including proximal deep‐vein thrombosis, in patients undergoing total knee arthroplasty. With the numbers available, there was no significant difference between groups with regard to the occurrence of major hemorrhagic complications; however, the rate of overall hemorrhagic complications was higher in the enoxaparin group.

This paper reports analysis obtained from 200 implant cases retrieved from humans and submitted to the American Academy of Implant Dentistry Research Foundation, Medical College of Georgia implant retrieval center. The samples that were not decalcified were embedded in polymethylmethacrylate and examined with scanning electron microscopy and routine light, polarized, or Nomarski microscopy. Cases included both orthopedic and dental implants, as well as entire mandibles and portions of maxillae obtained at autopsy. A significant number of submitted implants had substantial amounts of adhered bone, which permitted evaluation of human bone remodeling to osseointegrated implants. These implants failed because of implant fracture. As was observed with animal studies, healthy bone supported these implants, with the bone containing an interdigitating canaliculi network that provided communication between interfacial osteocytes and osteocytes deeper within the remodeled osteonal and trabecular bone. Earl...

We report analyses obtained from 135 implant cases retrieved from humans and submitted to the American Academy of Implant Dentistry Research Foundation–Medical College of Georgia Implant R...

Ultrastructural examination of the morphology and morphometry of the bone supporting uncoated titanium and ceramic implants was assessed in an experimental animal model involving 120 implants placed into the mandibles of 30 adult mongrel dogs. Further, preliminary morphologic and morphometric observations of the bone supporting uncoated and hydroxylapatite-coated endosteal titanium implants was evaluated in a second investigation involving 72 implants placed into the mandibles and maxillae of 6 additional dogs. A densely mineralized collagen fiber matrix was observed directly interfacing with uncoated implants. The only material interposed between the implant and bone matrix was a 20- to 50-nm electron-dense material suggestive of a proteoglycan. Also seen in these same osseointegrated implants were narrow unmineralized zones interposed between the implant and bone matrix. In these zones of remodeling bone, numerous osteoblasts were observed interacting with the collagen fiber matrix. It was shown that a normal homeostasis of anabolic osteoblastic activity and catabolic osteoclastic activity resulted in bone remodeling and the resultant osseointegration of the implants. Hydroxylapatite-coated implants intimately interfaced with healthy bone. The mineralized matrix extended into the microporosity of the HA coating. This matrix contained viable osteocytes.

SN 1997D in NGC 1536 is possibly the least luminous and energetic Type II supernova discovered to date. The entire light curve is subluminous, never reaching $M_V = -14.65$. The radioactive tail follows the 56Co decay slope. In the case of nearly complete trapping of the $\gamma$-rays, the 56Ni mass derived from the tail brightness is extremely small, $\sim 0.002$ \M. At discovery the spectra showed a red continuum and line velocities of the order of 1000 \kms. The luminosity and the photospheric expansion velocity suggest that the explosion occurred about 50 days before discovery, and that a plateau probably followed. Model light curves and spectra of the explosion of a 26 \M\ star successfully fit the observations. Low mass models are inconsistent with the observations. The radius of the progenitor, constrained by the prediscovery upper limits, is \r0 \ltsim 300 \R. A low explosion energy of $\sim 4 \times 10^{50}$ ergs is then required in the modeling. The strong \ion{Ba}{2} lines in the photospheric spectra are reproduced with a solar abundance and low $T_{eff}$. A scenario in which the low 56Ni mass observed in SN 1997D is due to fall--back of material onto the collapsed remnant of the explosion of a 25--40 \M star appears to be favored over the case of the explosion of an 8--10 \M\ star with low 56Ni production.

Social science scholarship is increasingly addressing the dynamics of gender, race and class in various institutional contexts. Criminological research is no exception to this trend. Within the criminological sciences, postmodern research is also gaining greater attention and respectability. Notwithstanding the discipline's recent emphasis on postmodernity and cultural plurality, little attention has been given to criminological theory and how the voice of and way of knowing for women, minorities and the poor are represented within its own discourse. This article represents one preliminary step in that direction. At issue is the psychic configuration of criminological reality. Our method of analysis incorporates the conceptual tools of Jacques Lacan's psychoanalytic theory, especially his reliance on several topological constructs. We argue that Lacan's complex social system provides us with the interpretative tools necessary to examine theories of crime as a manifestation of culture and the psychological roots of cultural inclusivity embedded within its discourse. Our provisional assessment suggests that while criminology offers important insights relevant to gender, race and class, it has essentially failed to make sense of these differences within its own theoretical language. We argue that this is because the language of modernist (and premodernist) criminology is already prestructured (psychically encoded) to exclude these differences.

This report presents transmission electron and high voltage transmission electron microscopic observations of bone and associated remodeling tissues directly interfacing with endosteal dental implants. Undecalcified interfacial tissues were serially sectioned from mandibular samples encasing 60 implants placed into 30 dogs. Two-dimensional ultrastructural analyses and three-dimensional stereology showed that osteogenesis adjacent to dental implants is a dynamic interaction of osseous cells and a collagenous fiber matrix. This study showed that the interfacial bone consists of a mineralized collagen fiber matrix associated with an inorganic (hydroxylapatite) matrix. This study suggested that an unmineralized collagen fiber matrix initially is laid down directly at the implant surface, and that this matrix then is mineralized. Osteoblasts interacted with this matrix, eventually becoming encased within developing lacunae during the remodeling process. This process formed the cellular (osteocyte) aspects of the developed bone. Osteocyte processes extended through canaliculi directly to the implant surface. Apparently, these processes also were entrapped within canaliculi during the mineralization events. At times, these processes paralleled the implant surface. The bone-implant interfacial zone was primarily fibrillar (both mineralized and unmineralized) in morphology, with an electron-dense, ruthenium positive deposition. This electron-dense material was approximately 20 to 50 nanometers in thickness, and only this thin layer separated the remodeled mineralized bone from the implant.

Uncultivated plants growing on disturbed sites may be useful for assessing the bioavailability of some metals in soils, and thus the potential for metal mobilization up the terrestrial food chain, an important element in ecological risk assessment. A planted chicory cultivar (Cichorium intybus L. var. foliosum Hegi.) and the uncultivated plants horseweed (Canada fleabane) (Erigeron canadensis L.) and dogfennel (Eupatorium capillifolium (Lam.) Small) were evaluated for their ability to act as index plant species for soil Cd, Cr, Ni, and V at two field sites where these metals had been applied five yr previously to two highly weathered sandy Ultisols. Soil Cd was available to all analyzed plant tissues of all three plant species at both sites, particularly on the sandier Blanton soil. Chicory was an effective index plant for Cd on the finer textured Orangeburg soil but functioned as an indicator plant (toxicity symptoms were observed) on the sandier Blanton soil. Horseweed and dogfennel were effective index plants for Cd in both contaminated soils. Soil Cr, Ni, and V were less bioavailable than soil Cd and plant metal uptake was more sensitive to residual soil Cr, Ni, and V than was soil extraction with double acid. Horseweed and chicory may have potential as index plants for soil Cr. Chicory may have potential as a Ni index plant. Chicory and dogfennel may have potential as V index plants.

Numerical simulations have been performed to study the flowfield and near-field noise of a supersonic rectangular jet with two paddles inserted into the flow. The paddles cause a strong flapping motion to develop that enhances mixing of the jet with the surroundings. These simulations have been used to determine the flapping motion's frequency, the mixing enhancement, the near-field noise, and the thrust loss associated with the paddles and to study the acoustic feedback mechanism that modulates the flapping motion. The flapping frequency has been estimated using the pitot pressure distributions at a sequence of times and Fourier analysis of the local pressure and z component of velocity. For paddles located x/h = 7.3 from the nozzle, where h is the narrow dimension of the nozzle, a frequency of 4700 Hz [St(h) = 0.136] with an amplitude of 157.5 dB at the nozzle lip has been predicted and is in agreement with experimental results. The pitot pressure drop, the mass, and the x-momentum fluxes along the flow direction have been used as a measure of jet mixing for jets with and without paddles inserted into the flow. In our numerical simulations, a control volume approach was used to estimate the thrust loss caused by the insertion of the paddles. The computational value of 13% is close to the experimental value of 14.4%, considering that the physical support for the paddles in the experiments is not included in the simulations. A special sequence of local pressure distribution plots, which highlight the acoustic waves, has been used to study the feedback mechanism that modulates the flapping motion.

Crossbred steers (n = 20; 235 ± 4 kg) were fed for 53 d during a receiving period to determine if supplementing chromium (Cr; KemTRACE Chromium Propionate 0.04%, Kemin Industries, Des Moines, IA) would alter glucose or lipid metabolism of newly received cattle. Chromium premixes were supplemented to add 0 (Con) or 0.2 mg/kg of Cr to the total diet on a DM basis. Cattle were fitted with jugular catheters on d 52. A glucose tolerance test (GTT) and an insulin sensitivity test (IST) were conducted on d 53. Blood samples were collected from -60 to 150 min relative to each infusion. Serum was isolated to determine glucose, insulin, and NEFA concentrations. Throughout GTT, no differences were detected in glucose concentrations, glucose clearance rates (k), or preinfusion insulin concentrations (P0.50), but insulin concentrations postinfusion tended (P = 0.06) to be greater for the Cr-supplemented steers. This caused an increase in the insulin to glucose ratio (I:G) from 0 to 150 min postinfusion for the Cr-supplemented steers (P = 0.03). In addition, NEFA concentrations during GTT were lower (P ≤ 0.01) for Cr-supplemented steers both preinfusion and postinfusion. During IST, there was no treatment effect on glucose concentrations preinfusion (P = 0.38), but postinfusion glucose concentrations were greater (P0.01) in the Cr-supplemented steers. The k of Cr-supplemented steers tended (P = 0.06) to be faster than Con steers from 30 to 45 min postinfusion. During the same test, there was no treatment effect detected for insulin concentrations (P0.33). The I:G were not affected by treatment (P0.40).Concentrations of NEFA were reduced (P0.01) both preinfusion and postinfusion during IST for Cr-supplemented steers. Results of this study indicate that supplementation of Cr can significantly alter lipid metabolism. This suggests that these steers had less dependence on lipid metabolism for energy or sensitivity of adipose tissue to antilipolytic signals was reduced. Results of glucose and insulin metabolism were inconsistently modified after a GTT and an IST.

Crossbred steers (n = 180; 230 ± 6 kg) were fed during a 56-d receiving period to determine if supplementing chromium (Cr; KemTRACE Chromium Propionate 0.04%, Kemin Industries) would improve feedlot performance and health of newly-received cattle. A completely randomized block design (36 pens; 9 pens/treatment; 5 steers/pen) was used. Chromium premixes were supplemented to add 0 (Con), 0.1, 0.2, or 0.3 mg/kg of Cr to the total diet on a DM basis. No differences were detected on d 0 or after the first 14 d on feed. From d 0 to d 28, DMI (P = 0.07) and ADG increased linearly (P = 0.04) as Cr concentrations increased. From d 0 to d 56, BW (P = 0.08) displayed a tendency to increase linearly, and consequently ADG and G:F increased linearly (P ≤ 0.05) as Cr concentrations increased. The number of steers treated at least once for respiratory symptoms tended (P = 0.07) to linearly decrease as Cr concentrations increased. Twenty additional steers (235 ± 4 kg) were fed 56 d to determine if supplementing Cr (Con or 0.2 mg/kg Cr) would alter the metabolic response of newly-received cattle to a lipopolysaccharide (LPS) challenge. Cattle were fitted with jugular catheters on d 52. On d 55, blood samples were collected at 0.5-h intervals from -2 to 8 h, and again at 24 h relative to a LPS challenge (0.5 μg/kg BW) at 0 h. Serum glucose, insulin, and NEFA concentrations were determined from blood samples. Steer BW was also measured at cannulation, and 24 h and 8 d post-LPS. Steer BW did not differ at cannulation (P = 0.37), but 24 h post-LPS, Cr-supplemented steers had lost less BW (P = 0.03). Pre-LPS glucose concentration did not differ (P = 0.97). Post-LPS, there was a time × treatment interaction (P0.01) such that glucose concentration peaked earlier (0.5 h) and at a greater concentrations in Cr-supplemented steers (P0.01). Insulin concentration did not differ between treatments pre- or post-LPS (P0.13). Concentration of NEFA did not differ pre-LPS (P = 0.54); but 0.5 h post-LPS Cr-treated steers produced a greater peak NEFA concentration (P0.04). Results of this study indicate that supplementation of Cr to the basal diet can have beneficial effects on the performance and health of newly-received steers. These data also suggest that supplementation of Cr attenuated BW loss and allowed for a quicker recovery after a LPS challenge.

X-ray diffraction, iodometric titration, resistivity and SQUID magnetometry measurements have been performed on samples of YSrBaCu2.6Fe0.4O6+z in which yttrium has been partially replaced by calcium. The calcium-free compound is semiconducting but superconductivity is restored for x>0.05. The normal-state resistivity decreases and Tc increases with increasing Ca concentration. The effective valence of copper decreases with increasing calcium content and there is also some loss of oxygen. The observed behaviour is quite similar to that previously reported for samples which were doped with Al but values of Tc are generally lower with Fe doping. This is thought to be due primarily to the fact that the Fe partially occupies the Cu(2) sites in the superconducting Cu-O planes.

The discovery of X-ray, optical and radio afterglows of gamma-ray bursts (GRBs) and the measurements of the distances to some of them have established that these events come from Gpc distances and are the most powerful photon emitters known in the Universe, with peak luminosities up to 10^52 erg/s. We here report the discovery of an optical transient, in the BeppoSAX Wide Field Camera error box of GRB980425, which occurred within about a day of the gamma-ray burst. Its optical light curve, spectrum and location in a spiral arm of the galaxy ESO 184-G82, at a redshift z = 0.0085, show that the transient is a very luminous type Ic supernova, SN1998bw. The peculiar nature of SN1998bw is emphasized by its extraordinary radio properties which require that the radio emitter expand at relativistical speed. Since SN1998bw is very different from all previously observed afterglows of GRBs, our discovery raises the possibility that very different mechanisms may give rise to GRBs, which differ little in their gamma-ray properties.

The discovery of the peculiar supernova (SN) 1998bw and its possible association with the gamma-ray burst (GRB) 980425$^{1,2,3}$ provide new clues to the understanding of the explosion mechanism of very massive stars and to the origin of some classes of gamma-ray bursts. Its spectra indicate that SN~1998bw is a type Ic supernova$^{3,4}$, but its peak luminosity is unusually high compared with typical type Ic supernovae$^3$. Here we report our findings that the optical spectra and the light curve of SN 1998bw can be well reproduced by an extremely energetic explosion of a massive carbon+oxygen (C+O) star. The kinetic energy is as large as $\sim 2-5 \times 10^{52}$ ergs, more than ten times the previously known energy of supernovae. For this reason, the explosion may be called a `hypernova'. Such a C+O star is the stripped core of a very massive star that has lost its H and He envelopes. The extremely large energy, suggesting the existence of a new mechanism of massive star explosion, can cause a relativistic shock that may be linked to the gamma-ray burst.

An urban-oriented emergency assessment system for airborne Chemical, Biological, and Radiological (CBR) threats, called CT-Analyst and based on new principles, gives greater accuracy and much greater speed than possible with current alternatives. This paper explains how this has been done. The increased accuracy derives from detailed, three-dimensional CFD computations including, solar heating, buoyancy, complete building geometry specification, trees, wind fluctuations, and particle and droplet distributions (as appropriate). This paper shows how a very finite number of such computations for a given area can be extended to all wind directions and speeds, and all likely sources and source locations using a new data structure called Dispersion Nomographs. Finally, we demonstrate a portable, entirely graphical software tool called CT-Analyst that embodies this entirely new, high-resolution technology and runs effectively on small personal computers. Real-time users don't have to wait for results because accurate answers are available with near zero-latency (that is 10 - 20 scenarios per second). Entire sequences of cases (e.g. a continuously changing source location or wind direction) can be computed and displayed as continuous-action movies. Since the underlying database has been precomputed, the door is wide open for important new real-time, zero-latency functions such as sensor data fusion, backtracking to an unknown source location, and even evacuation route planning. Extensions of the technology to sensor location optimization, buildings, tunnels, and integration with other advanced technologies, e.g. micrometeorology or detailed wind field measurements, will be discussed briefly here.

The standard practice in total joint arthroplasty has included the use of postsurgical drains to minimize perioperative wound complications, particularly infection. This practice is not without cost and potential morbidity. Our recent cemented and cementless total knee arthroplasties (TKAs) have been done without the use of postoperative surgical drains and without any appreciable increase in wound complications. To confirm this, we retrospectively reviewed 227 consecutive TKAs, specifically evaluating perioperative wound complications. No statistical increase in perioperative complications in TKAs without drains was found. A lower percentage of complications was seen in the cementless population when compared with cemented or drained knees. We suggest that surgical drainage is not required in TKA, even when cementless fixation is used.

The extended proximal femoral osteotomy is becoming increasingly popular in revision total hip replacement. Our study was done to determine the femoral stem length required for stable fixation of a cementless femoral component after an extended proximal femoral osteotomy. Three lengths of the S-ROM femoral stem were implanted in paired cadaver femora and tested under torsional and axial loads. The results indicate that the standard (160 mm) and long (215 mm) stems do not provide adequate torsional stability after a 160 mm extended proximal femoral osteotomy. The extra-long (255 to 315 mm) stems provided significantly greater stability, suggesting that the extended proximal femoral osteotomy may need to be bypassed by more than 2 cortical diameters, especially when a flexible stem such as the S-ROM is used.

Patients treated with total knee arthroplasty are at high risk for the development of venous thromboembolism postoperatively. This study compared the efficacy and safety of two common thromboprophylactic agents, enoxaparin (a low-molecular-weight heparin) and warfarin.Three hundred and forty-nine patients were included in a prospective, randomized, multicenter, open-label, parallel-group clinical trial. Treatment with enoxaparin (30 mg, administered subcutaneously twice daily) or warfarin (adjusted to an international normalized ratio of 2 to 3) was initiated during the immediate postoperative period, within eight hours after the surgery, and was continued for four to fourteen days. Venous thromboembolism was defined as deep-vein thrombosis documented by contrast venography, symptomatic deep-vein thrombosis documented by lower-extremity ultrasonography, or symptomatic pulmonary embolism confirmed by a positive lung scan or pulmonary angiography.In the all-treated-patients group, eighty (45%) of the 176 warfarin-treated patients had venous thromboembolism: fifty-nine (34%) had distal deep-vein thrombosis; twenty (11%), proximal deep-vein thrombosis; and one (0.6%), pulmonary embolism. Venous thromboembolism developed in significantly fewer (p = 0.0001) enoxaparin-treated patients (forty-four of 173; 25%): forty-one (24%) had distal deep-vein thrombosis, three (2%) had proximal deep-vein thrombosis, and none had pulmonary embolism. The enoxaparin-treated patients also had a significantly lower prevalence of proximal deep-vein thrombosis (p = 0.002). The estimated odds for the development of venous thromboembolism were 2.52 times greater (95% confidence interval, 2.00 to 3.19) with warfarin than they were with enoxaparin. Major hemorrhage occurred in four warfarin-treated patients and nine enoxaparin-treated patients; with the numbers available, this difference was not significant (p = 0.17). Clinically important operative-site hemorrhage occurred in six (3%) of the warfarin-treated patients and twelve (7%) of the enoxaparin-treated patients (p = 0.15).A fixed 30-mg subcutaneous dose of enoxaparin, administered twice daily, with the first dose administered within eight hours after the completion of surgery, was significantly more effective than adjusted-dose warfarin in reducing the occurrence of asymptomatic venous thromboembolism, including proximal deep-vein thrombosis, in patients undergoing total knee arthroplasty. With the numbers available, there was no significant difference between groups with regard to the occurrence of major hemorrhagic complications; however, the rate of overall hemorrhagic complications was higher in the enoxaparin group.

This paper reports analysis obtained from 200 implant cases retrieved from humans and submitted to the American Academy of Implant Dentistry Research Foundation, Medical College of Georgia implant retrieval center. The samples that were not decalcified were embedded in polymethylmethacrylate and examined with scanning electron microscopy and routine light, polarized, or Nomarski microscopy. Cases included both orthopedic and dental implants, as well as entire mandibles and portions of maxillae obtained at autopsy. A significant number of submitted implants had substantial amounts of adhered bone, which permitted evaluation of human bone remodeling to osseointegrated implants. These implants failed because of implant fracture. As was observed with animal studies, healthy bone supported these implants, with the bone containing an interdigitating canaliculi network that provided communication between interfacial osteocytes and osteocytes deeper within the remodeled osteonal and trabecular bone. Early dental implants containing a coating of beads showed a connective tissue interface, which corresponded to the bead surface of specific orthopedic implants that underwent some degree of micromovement. This is in contrast with the excellent response reported for successful contemporary beaded implants. Significant numbers of osseointegrated fractured hydroxyapatite (HA)-coated dental implants demonstrated the adequate serviceability of these implants before biomaterial fracture. In contrast, the HA coating was dissociated from retrieved orthopedic implants, leading to extensive cup loosening and case failure. This study, therefore, underscores the need for evaluation of failed human dental and orthopedic implants. Correlations can be drawn between human retrieval and experimental animal studies.

The threat of a chemical and/or biological contaminant release in an urban environment is a major concern to both mili tary and civi l ian sectors. Accurate and detailed modeling of contaminant transport in urban environments that accounts for complex physical processes and varying meteorological conditions is central to any consequence management technology aimed at providing a timely, effective response to a chemical or biological threat. To facilitate necessary improvements to contaminant transport models being applied to this class of problems, it is important to assess the ability of a given numerical model to predict atmospheric transport and dispersion around single and multiple complex buildings. Such assessments can be derived from calibration and validation studies that rely on experimental data, and numerical sensitivity studies of computational parameters. In this paper, we present the status of three ongoing Computational Fluid Dynamics modeling init iat ives, supported in part by High Performance Computing Challenge resources, and focus on the important f luid dynamic issues. The threedimensional, time-dependent computational studies are performed using FAST3D-CT, an extension of the Naval Research Laboratory's scalable FAST3D model Research Aerospace Engineer. Code 6410. Senior Member A I A A 'Chief Scientist and Director. Code 6400. Fellow A IA A ' Re search Physicist, Code 6440 'Research Physicist Code 6440 ^Staff Scientist This paper is declared a work of the U.S. Government and is not subject to copyright protection in the Uni ted States. to contaminant transport problems for urban and environmental hazard assessment. The first initiative involves a validation study of flow over a surfacemounted cube using existing wind tunnel and water tank databases. The second investigates the effects of inflow velocity characteristics on flow patterns around a complex full-scale building. This is accomplished through a series of calibration studies using field test data and numerical sensitivity studies. The third initiative focuses on the simulation of single and multiple releases driven by prescribed and forecasted winds through a multi-kilometer section of a model city resembling downtown Washington, DC. This third initiative has led to the development of a zerolatency, model-based approach to sensor integration for the protection of single and/or multiple facilities in high-density urban environments.

We report analyses obtained from 135 implant cases retrieved from humans and submitted to the American Academy of Implant Dentistry Research Foundation--Medical College of Georgia Implant Retrieval Center. The undecalcified samples were embedded in polymethyl-methacrylate and examined with scanning electron microscopy and with routine light via polarized or Nomarski microscopy. Cases included both orthopedic and dental implants as well as entire mandibles obtained at autopsy. Significant numbers of submitted implants had substantial amounts of adhered bone, which permitted evaluation of human bone remodeling to osseointegrated implants. These implants failed because of implant fracture. As has been observed in animal studies, an interdigitating canaliculi network provided communication between interfacial osteocytes and osteocytes deeper within the remodeled osteonal and trabecular bone. Significant numbers of osseointegrated fractured hydroxyapatite-coated dental implants demonstrated the adequate serviceability of these implants prior to biomaterial fracture. In contrast, the hydroxyapatite coating was dissociated from retrieved orthopedic implants, leading to extensive cup loosening and case failure. Caution is advised for the use of hydroxyapatite-coated acetabular implants. This study therefore underscores the need for evaluation of failed human dental and orthopedic implants. Correlations can be drawn between human retrieval and experimental animal studies.

Among the major uncertainties involved in the Chandrasekhar mass models for Type Ia supernovae (SNe Ia) are the companion star of the accreting white dwarf (or the accretion rate that determines the carbon ignition density) and the flame speed after ignition. We present several new constraints on the companion star in the progenitor system, which includes: 1) nucleosynthesis results from relatively slow deflagration to constrain the rate of accretion from the companion star, and 2) Galactic chemical evolution models to constrain the main-sequence lifetime of the companion stars.

The origin of an observational diversity of supernova types, namely, Type Ia, Ib, Ic, II-P, II-L, IIb, and IIn, has not been well understood. We propose a new scenario that explains how such a diversity can result from the common envelope evolution of binary stars. The recent nearby supernovae SN 1993J and SN 1994I have provided particularly useful material to clarify the supernova-progenitor connection. For a progenitor of Type IIb supernova 1993J, we propose that merging of two stars in a close binary is responsible for the formation of a thin H-rich envelope. For a progenitor of Type Ic supernova 1994I, we propose a bare C+O star that has lost both H and He envelope after common envelope phase. By generalizing these scenarios, we show that common envelope evolution in massive close binary stars leads to various degree of stripping of the envelope mass of massive star. This can naturally lead to the explanation of the origin of Type II-L, IIn, IIb, Ib, and Ic in a unified manner. The binary hypothesis to explain the diversity of supernovae can be substantiated with new information on SN IIb 1993J and SN Ic 1994I. Hydrodynamical and nucleosynthesis models for these supernovae (including Rayleigh-Taylor instabilities) and their light curves are compared with observations. Based on these modeling, we suggest that the subluminous SN I 1993R might be a SN Ib originating from the smallest mass progenitor. Finally, circumstellar interactions of SN 1993J are examined to compare with X-ray observations and infer the density structure and instabilities of the ejecta.

Avascular necrosis (AVN) of the femoral head has been described in the literature in patients infected with the human immunodeficiency virus. It has been associated with either a hypertriglyceridemic state or the presence of antiphospholipid antibodies. We describe a case of AVN of the medial femoral condyle in an HIV-infected patient associated with a hypertriglyceridemic state.

We report on simple, parallel algorithms designed to compute unsteady shocked flows around complex geometries very efficiently. To resolve dynamic shock phenomena without spuri­ous compressions and rarefactions appearing as a result of unphysical regions of local curvature in the numerical representation of the body or boundary geometry, an accurate method to resolve these surfaces is required. The Virtual Cell Embedding (VCE) method is introduced, an efficient new approach for resolving complex geometries on a structured, orthogonal grid with little sacrifice in speed or memory. Unstructured grid methods and adaptive gridding methods for body-fitted structured grids are common alternative techniques to resolve complex geometries. These methods, however, require large amounts of memory and are computationally expensive. In contrast, the VCE method requires very little extra memory and CPU time to define the shape of a body accurately compared to the simple, orthogonal grid solutions computed as if the body were not there. The VCE method has been combined with a new efficient Flux-Corrected Trans­port (FCT) algorithm in a general simulation program, FAST3D. FAST3D is a three-dimensional unsteady flow solver and runs on vector computers (Convex C210, Cray), modern workstations (IBM RISC 6000, DEC Alpha), and high performance parallel computers (32-node and 512-node Intel iPSC/860) interchangeably. A video has been prepared of several simulations to illustrate this new capability.

The management of ipsilateral fractures of the femoral neck and shaft has proved to be a challenge to the orthopaedist. Most major institutions have treatment protocols that emphasize early rigid stabilization of the femoral-neck fracture to minimize the incidence of avascular necrosis of the femoral head. Since 1985, the authors' protocol has been to reduce and stabilize the femoral-neck fracture anatomically, followed by treatment of the femoral-shaft fracture. In 1990, we began treating this segmental fracture pattern with reconstruction nails. This study reviews the cases of 11 patients treated at the Medical College of Georgia Hospital from November 1985 to March 1992. Nine of the 11 underwent surgery within 12 hours of injury; 4 of these patients were treated with reconstruction nails. The mean follow-up was 2 years. Seven of the 11 had a good functional outcome, whereas 4 had a fair outcome. The results indicate that patients with ipsilateral fractures of the femoral neck and shaft can obtain good results when early (12 hours) rigid anatomic stabilization of the femoral neck is performed. The authors recommend utilizing a reconstruction nail for stabilizing this dual fracture whenever possible.

The bone interface to implanted biomaterials (both orthopaedic and dental implants) is the critical component for initial fixation of these uncemented biomedical devices. The mechanism of osteogenesis at the biomaterial surface after surgical placement is critical to understand to enhance osseointegration , and thereby implant success. The purpose of this paper is to report comprehensive and correlative electron and light microscopic observations from a five-year study involving the bone interface to 120 implants placed into 30 adult animals.As a model system to evaluate bone and associated tissue interfaces to implanted biomaterials, 120 endosteal dental implants were placed into the mandibles of 30 adult mongrel dogs. Premolars were extracted and the sites were allowed to heal for 2 months prior to implantation. Surgery employed low speed drilling, copious internal and external irrigation and followed manufacturer recommendations for these commercially available implants.