Dense medium separation circuits use a dense medium to separate low density waste material from high density valuable minerals. Since the dense medium is an expensive consumable, it is recovered ...after separation of the valuable minerals from waste. A dynamic nonlinear model of a dense medium separation circuit of an iron ore plant in South Africa is developed to track the flow of medium in the circuit. An extended Kalman filter is designed for estimating observable but unmeasured states. The model is validated using online plant data. This paper serves as a precursor for further work to detect and mitigate expensive medium losses in the circuit.
•A dense medium separation circuit is modelled from first principles.•Each unit process model is evaluated for state observability.•The states are estimated from industrial data using an extended Kalman filter.•The results indicate how the estimates can be used to detect medium losses.
Whereas dendritic cells (DC) are known to be potent activators of T cells both in vitro and in vivo, the critical costimulatory molecules expressed on DC are not well characterized. Using ...immunocytochemical and molecular techniques we find that splenic DC express B7/BB1, the counter-receptor for CD28. Moreover, expression of B7/BB1 is upregulated on epidermal Langerhans cells (LC) during their functional maturation into potent T cell stimulators. In blocking experiments, we find that participation of B7/BB1 is required for optimal proliferation of unprimed, allogeneic T cells in DC-driven, primary mixed leukocyte reactions. These data demonstrate that the regulated expression of B7/BB1 on DC may be important in the initiation of a primary T cell response.
We present new, near-aphelion, time series of photometry of Comet 2P/Encke in Cousins-R band. With these light curves we find that the dominant, synodic rotational periodicity is either
P
0
=
11.079
...±
0.009
h
or
2
P
0
=
22.158
±
0.012
h
. This is in contrast to data from the 1980s published by others that are consistent with 15.08- and 22.6-h periods. Those periods do not satisfy our phased light curves, and also the 1980s data are not easily reconciled with our periods. This could be due to P/Encke having non-principal axis rotation or due to a drift in the rotation period caused by outgassing torques. We observed the comet at five epochs: July, August, September, and October 2001, and September 2002, and the comet was at times intrinsically brighter than expected for a bare nucleus, due to an apparent contribution from an unresolved coma. Three-quarters of the data were obtained in the second and fifth epochs, and we analyzed these two time series using both the phase-dispersion minimization and “WindowCLEAN” techniques. At both epochs and with both techniques strong periodicities were found near frequencies
f
0
=
2.16
d
−1
and
f
1
=
4.35
d
−1
. By then using visual inspection of the phased light curves to corroborate these frequencies, and by using the data from the other three epochs to properly align light curve features, we were able to derive
P
0
and
2
P
0
as the only solutions that satisfy all our observations. The periodicity due to
f
1
is clearly seen in our data, but we cannot tell from our data alone whether it is a manifestation of the nucleus's shape, non-principal axis rotation, or both.
In March 2001, the Hayabusa spacecraft target, Asteroid 25143 Itokawa, made its final close approach to Earth prior to the spacecraft's launch. We carried out an extensive observing campaign from ...January to September 2001 to better characterize this near-Earth asteroid. Global physical properties of the surface of Itokawa were characterized by analyzing its photometric properties and behavior. Results included here capitalize on analysis of broadband photometric observations taken with a number of telescopes, instruments, and observers. We employed a Hapke model to estimate the surface roughness, single particle scattering albedo, single particle scattering characteristics, phase integral, and geometric and bond albedo. We find that this asteroid has a higher geometric albedo than average main belt S-class asteroids; this is consistent with results from other observers. The broadband colors of Itokawa further support evidence that this is an atypical S-class asteroid. Broadband colors show spectral characteristics more typically found on large-diameter main-belt asteroids believed to be space-weathered, suggesting the surface of this small diameter, near-Earth asteroid could likewise be space-weathered.
We are conducting a ground-based observational study of distant cometary nuclei with the aim of increasing the current database of physical parameters of individual objects, and to estimate the ...overall distributions of size, rotation period, axial ratio, and color indices. Additionally, we are obtaining CCD spectroscopy and photometry of established and potential targets of current and future spacecraft missions. The results presented here are derived from CCD imaging obtained using the 2.3-m Bok telescope of Steward Observatory (Arizona), obtained in May 2001, and the 5-m Hale telescope at Palomar Observatory (California), obtained in May 2000 and March 2001. Comets observed include 4P/Faye, 6P/d'Arrest, 22P/Kopff, 36P/Whipple, 50P/Arend, 78P/Gehrels 2, 92P/Sanguin, 107P/Wilson–Harrington, and 128P/Shoemaker–Holt 1-A. Of the nine comets observed, only Comets 4P/Faye and 50P/Arend displayed visible coma activity. We have performed either single
R filter or multi-filter (
BVRI) measurements on these comets, from which we obtain radius and broadband color estimates as well as
Afρ values for the active comets. For selected objects we have performed time-series
R filter imaging from which we have derived the rotation period and lower limits on the nuclear axial ratio and density. The radius results obtained are included in the cometary nucleus size distribution estimate by Weissman and Lowry (2003).
The use of narcotics has been found to be a modifiable risk factor for success of arthroplasty. We sought to determine the risk factors leading to increased narcotic use after total hip arthroplasty ...and total knee arthroplasty.
A retrospective chart review was performed on new patients presenting to an orthopedic reconstructive-service clinic. New patients aged 18 years or older with osteoarthritis of the hip or knee who presented over a 1-year period and underwent total knee arthroplasty or total hip arthroplasty were included. The Arkansas prescription monitoring program was then used to determine recent narcotic and benzodiazepine prescriptions filled within 3 months of surgery, and this was converted into morphine milligram equivalents (MME).
One hundred seventy-nine patients met the inclusion criteria. When compared with patients who did not take any preoperative opioids, narcotic- and tramadol-only users filled an average of 86% and 38% more MME, respectively. Benzodiazepine users required an average of 81% more MME postoperative than nonusers, and smokers required an average of 90% more MME postoperative than nonsmokers. Subjects with body mass index >40 kg/m2 had 82% higher average postoperative MME than subjects with body mass index <25 kg/m2. Age and sex had no significant correlation with postoperative narcotic use.
This study suggests that a patient's preoperative narcotic, tramadol, benzodiazepine, and tobacco use are correlated to the amount of postoperative narcotic prescriptions filled in the 3 months following surgery. Predisposition to substance abuse may be a characteristic which leads to increased postoperative narcotic use.
The surgical treatment of fistula-in-ano frequently results in recurrence of the fistula or postoperative anal incontinence. Despite these problems, most patients are satisfied with the results of ...their surgery. To clarify this apparent discrepancy, we attempted to identify factors that affect patient's lifestyles and may contribute to their satisfaction.
A questionnaire was mailed to 624 patients surgically treated for cryptoglandular fistula-in-ano at the University of Minnesota during a five-year period. Three hundred seventy-five patients returned their questionnaires. Patients who were followed up for a minimum of one year were included in this retrospective study. Associations between postoperative complications and patient satisfaction were identified by chi-squared tests and multiple logistic regression. Attributable fractions for patient dissatisfaction were calculated using study population dissatisfaction rates.
Patient satisfaction was strongly associated with fistula recurrence, difficulty holding gas, soiling of undergarment, and accidental bowel movements. Effects of incontinence on patient quality of life were also significantly associated with patient satisfaction as was the number of lifestyle activities affected by incontinence. Patients with fistula recurrence reported a higher dissatisfaction rate (61 percent) than did patients with anal incontinence (24 percent), but the attributable fraction of dissatisfaction for incontinence (84 percent) was greater than that for fistula recurrence (33 percent). Patient satisfaction was not significantly associated with age, gender, history of previous fistula surgery, type of fistula, surgical procedure, time since surgery, or operating surgeon.
Patient satisfaction after surgical treatment for fistula-in-ano is associated with recurrence of the fistula, the development of anal incontinence, and with the effects of anal incontinence on patient lifestyle. In our series of patients treated mainly with laying open of the fistula tract, patients with fistula recurrence had a higher dissatisfaction rate than did patients with anal incontinence. However, because anal incontinence was more prevalent than fistula recurrence, a higher fraction of dissatisfaction was attributable to anal incontinence.
Tumor necrosis factor α (TNFα), a primary mediator of systemic responses to sepsis and infection, can be injurious to the organism when present in excessive quantities. Here we report that two types ...of naturally occurring soluble TNF receptors (sTNFR-I and sTNFR-II) circulate in human experimental endotoxemia and in critically ill patients and demonstrate that they neutralize TNFα-induced cytotoxicity and immunoreactivity in vitro. Utilizing immunoassays that discriminate between total sTNFR-I and sTNFR-I not bound to TNFα, we show that sTNFR-I-TNFα complexes may circulate even in the absence of detectable free TNFα. To investigate the therapeutic possibilities of sTNFR-I, recombinant protein was administered to nonhuman primates with lethal bacteremia and found to attenuate hemodynamic collapse and cytokine induction. We conclude that soluble receptors for TNFα are inducible in inflammation and circulate at levels sufficient to block the in vitro cytotoxicity associated with TNFα levels observed in nonlethal infection. Administration of sTNFR-I can prevent the adverse pathologic sequelae caused by the exaggerated TNFα production observed in lethal sepsis.
Context. In 2004 asteroid (2867) Steins has been selected as a flyby target for the Rosetta mission. Determination of its spin period and the orientation of its rotation axis are essential for ...optimization of the flyby planning. Aims. Measurement of the rotation period and light curve of asteroid (2867) Steins at a phase angle larger than achievable from ground based observations, providing a high quality data set to contribute to the determination of the orientation of the spin axis and of the pole direction. Methods. On March 11, 2006, asteroid (2867) Steins was observed continuously for 24 h with the scientific camera system OSIRIS onboard Rosetta. The phase angle was 41.7 degrees, larger than the maximum phase angle of 30 degrees when Steins is observed from Earth. A total of 238 images, covering four rotation periods without interruption, were acquired. Results. The light curve of (2867) Steins is double peaked with an amplitude of \approx0.23 mag. The rotation period is 6.052 similar to \pm\,\,0.007 h. The continuous observations over four rotation periods exclude the possibility of period ambiguities. There is no indication of deviation from a principal axis rotation state. Assuming a slope parameter of G = 0.15, the absolute visual magnitude of Steins is 13.05 \pm 0.03.
Quantitative MR imaging differences in an elderly population of subjects with various clinical disorders (including dementia, particularly Alzheimer's disease and vascular dementia) and disorders of ...mild cognitive impairment were examined. Potential quantitative MR differences were assessed by presence or absence of the apolipoprotein E (APOE) epsilon4 allele and by level of cognitive deficit.
One hundred eighty subjects with a diagnosis of dementia or other clinical disorders were identified from an eligible population of 5,677 elderly individuals. Age, duration of disease, and head size (where appropriate) were considered as covariates. APOE genotype was determined by polymerase chain reaction using buccal material. Axial and coronal intermediate- and T2-weighted MR images were quantified using a multispectral segmentation algorithm. Cognitive status was assessed by means of a modified Mini-Mental Status Examination.
All types of dementing illness showed significant volume reductions in the majority of structures examined, particularly in the total brain, hippocampus, and white and gray matter, and increased CSF and ventricular volumes. Subjects with mild cognitive impairment showed fewer atrophic changes but were still distinguishable from the 24 control subjects. Presence of an epsilon4 allele was associated with smaller hippocampal volume in subjects with Alzheimer's disease and vascular dementia within just 1 year of disease onset. For other analyses, atrophy related to the presence of the epsilon4 allele disappeared after controlling for age and length of disease.
The effects of the epsilon4 allele on brain morphology may be subtly expressed early in the development of dementia, but do not specifically affect cerebral atrophy thereafter. Cognitive impairment is associated with atrophy irrespective of diagnosis and presence of epsilon4.
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