Process evaluation of an environmental walking and healthy eating pilot in small rural worksites

Small Steps are Easier Together (SS) was a pilot environmental intervention in small rural worksites in Upstate New York in collaboration with Extension educators. Worksite leaders teamed with co-workers to select and implement environmental changes to increase walking steps over individual baseline and to choose healthy eating options over 10 weeks. Participants were 226 primarily white, women employees in 5 sites. A mixed methods process evaluation, conducted to identify determinants of intervention effectiveness and to explain differences in outcomes across worksites, included surveys, self-reports of walking and eating, interviews, focus groups, and an intervention log. The evaluation assessed reach, characteristics of recruited participants, dose delivered, dose received, and context and compared sites on walking and eating outcomes. Emergent elements of participant-reported dose received included: active leadership, visible environmental changes, critical mass of participants, public display of accomplishments, accountability to co-workers, and group decision making. Participants at sites with high reach and dose were significantly more likely than sites with low reach and dose to achieve intervention goals. Although this small pilot needs replication, these findings describe how these evaluation methods can be applied and analyzed in an environmental intervention and provide information on trends in the data.

Work conditions and the food choice coping strategies of employed parents

OBJECTIVE

How work conditions relate to parents' food choice coping strategies.

DESIGN

Pilot telephone survey.

SETTING

City in the northeastern United States (US).

PARTICIPANTS

Black, white, and Hispanic employed mothers (25) and fathers (25) randomly recruited from low-/moderate-income zip codes; 78% of those reached and eligible participated.

MAIN OUTCOME MEASURES

Sociodemographic characteristics; work conditions (hours, shift, job schedule, security, satisfaction, food access); food choice coping strategies (22 behavioral items for managing food in response to work and family demands (ie, food prepared at/away from home, missing meals, individualizing meals, speeding up, planning).

ANALYSIS

Two-tailed chi-square and Fisher exact tests (P < or = .05, unless noted).

RESULTS

Half or more of respondents often/sometimes used 12 of 22 food choice coping strategies. Long hours and nonstandard hours and schedules were positively associated among fathers with take-out meals, missed family meals, prepared entrees, and eating while working; and among mothers with restaurant meals, missed breakfast, and prepared entrees. Job security, satisfaction, and food access were also associated with gender-specific strategies.

CONCLUSIONS AND IMPLICATIONS

Structural work conditions among parents such as job hours, schedule, satisfaction, and food access are associated with food choice coping strategies with importance for dietary quality. Findings have implications for worksite interventions but need examination in a larger sample.

Bioluminescence imaging of point sources implanted in small animals post mortem: evaluation of a method for estimating source strength and depth

The performance of a simple approach for the in vivo reconstruction of bioluminescent point sources in small animals was evaluated. The method uses the diffusion approximation as a forward model of light propagation from a point source in a homogeneous tissue to find the source depth and power. The optical properties of the tissue are estimated from reflectance images obtained at the same location on the animal. It was possible to localize point sources implanted in mice, 2-8 mm deep, to within 1 mm. The same performance was achieved for sources implanted in rat abdomens when the effects of tissue surface curvature were eliminated. The source power was reconstructed within a factor of 2 of the true power for the given range of depths, even though the apparent brightness of the source varied by several orders of magnitude. The study also showed that reconstructions using optical properties measured in situ were superior to those based on data in the literature.

Trying to find the quickest way: employed mothers' constructions of time for food

OBJECTIVE

The study sought to develop an understanding of how employed mothers constructed time for food provisioning for themselves and their families.

DESIGN

A grounded theory approach and semistructured, in-depth interviews.

SETTING

A metropolitan area of approximately 1 million people in the northeastern United States.

PARTICIPANTS

Thirty-five low-wage employed mothers were purposively recruited to vary in occupation, race/ethnicity, education, household composition, and age using workplace, community, convenience, and snowball sampling.

PHENOMENON OF INTEREST

Low-wage employed mothers' constructions of time for food.

ANALYSIS

Interview transcripts were analyzed using the constant comparative method.

RESULTS

Most mothers expressed feelings of time scarcity. Mothers described 3 timestyles that reflected how they constructed time. Timestyles reflected mothers' experiences of strain and time scarcity, usual time management strategies, and sense of control over time. Mothers prioritized feeding their children but wanted to complete meals quickly in order to move on to other tasks.

CONCLUSIONS AND IMPLICATIONS

Recognizing issues of time scarcity and individual differences of timestyles and time management strategies can help researchers better understand food choice practices and assist practitioners in identifying practical food provisioning strategies for low-wage employed mothers. Food policies and recommendations should be evaluated for their relevance to the time scarcity and work strain issues that these mothers faced.

"A lot of sacrifices:" work-family spillover and the food choice coping strategies of low-wage employed parents

Integrating their work and family lives is an everyday challenge for employed parents. Competing demands for parents' time and energy may contribute to fewer meals prepared or eaten at home and poorer nutritional quality of meals. Thus, work-family spillover (feelings, attitudes, and behaviors carried over from one role to another) is a phenomenon with implications for nutrition and health. The aim of this theory-guided constructivist research was to understand how low-wage employed parents' experiences of work-family spillover affected their food choice coping strategies. Participants were 69 black, white and Latino mothers and fathers in a Northeastern US city. We explored participants' understandings of family and work roles, spillover, and food choice strategies using open-ended qualitative interviews. Data analysis was based on the constant comparative method. These parents described affective, evaluative, and behavioral instances of work-family spillover and role overload as normative parts of everyday life and dominant influences on their food choices. They used food choice coping strategies to: (1) manage feelings of stress and fatigue, (2) reduce the time and effort for meals, (3) redefine meanings and reduce expectations for food and eating, and (4) set priorities and trade off food and eating against other family needs. Only a few parents used adaptive strategies that changed work or family conditions to reduce the experience of conflict. Most coping strategies were aimed at managing feelings and redefining meanings, and were inadequate for reducing the everyday hardships from spillover and role overload. Some coping strategies exacerbated feelings of stress. These findings have implications for family nutrition, food expenditures, nutritional self-efficacy, social connections, food assistance policy, and work place strategies.

Quantification of bioluminescence images of point source objects using diffusion theory models

A simple approach for estimating the location and power of a bioluminescent point source inside tissue is reported. The strategy consists of using a diffuse reflectance image at the emission wavelength to determine the optical properties of the tissue. Following this, bioluminescence images are modelled using a single point source and the optical properties from the reflectance image, and the depth and power are iteratively adjusted to find the best agreement with the experimental image. The forward models for light propagation are based on the diffusion approximation, with appropriate boundary conditions. The method was tested using Monte Carlo simulations, Intralipid tissue-simulating phantoms and ex vivo chicken muscle. Monte Carlo data showed that depth could be recovered within 6% for depth 4-12 mm, and the corresponding relative source power within 12%. In Intralipid, the depth could be estimated within 8% for depth 4-12 mm, and the relative source power, within 20%. For ex vivo tissue samples, source depths of 4.5 and 10 mm and their relative powers were correctly identified.

Sisters in health: experiential program emphasizing social interaction increases fruit and vegetable intake among low-income adults

Sisters in Health, a nutrition education program aimed at increasing fruit and vegetable consumption among low-income women, includes active food experiences, positive social settings, a flexible meeting series, and small-group facilitation by paraprofessionals. The program's impact was evaluated in a nonrandom sample of 269 low-income adults in 32 intervention and 10 control groups in New York State using a quasi-experimental, pre-/postprogram evaluation design. Intervention groups reported increased fruit and vegetable consumption, measured by a brief screener, of 1.6 times a day (versus 0.8 times in the control groups) and were 0.44 times more likely to be eating fruits and vegetables 5 or more times a day (P < .05) than control groups. Group support, taste, and food skill experiences can be effective for increasing fruit and vegetable consumption.

Experimental verification of the effect of refractive index mismatch on the light fluence in a turbid medium

Diffusion theory is often used to model the transport of light within tissue. It can be used to calculate the light fluence rate in tissue, for example, during photodynamic therapy, or to measure the absorption and scattering properties of tissue. For both of these applications, the influence of the interface between the tissue and the exterior medium on the fluence rate inside the tissue must be known in order to make accurate calculations. We present an experimental investigation of the effect of the refractive index mismatch at the tissue interface on the internal light fluence rate and on the spatially resolved diffuse reflectance as the boundary conditions of the tissue/external medium are changed. The effects of changing the relative refractive index at the boundary are compared to predictions of diffusion theory. The effect of the refractive index mismatch is predicted correctly by diffusion theory.

A diffusion theory model of spatially resolved fluorescence from depth-dependent fluorophore concentrations

A photon diffusion model has been developed to calculate the steady-state spatially resolved fluorescence from pencil beam excitation in layered tissue. The model allows the calculation of both the excitation reflectance and the fluorescence escape for an arbitrary continuous depth distribution of tissue optical properties and fluorophore concentration. The validity of this model was verified by comparison with Monte Carlo simulations and experimental measurements using phantoms with tissue-like optical properties. The potential usefulness of the spatially resolved fluorescence was explored using the model and simulations of realistic drug distributions. It was shown that using this technique it may be possible to quantify the diffusion of a topically administered drug into the skin, or the photobleaching of a sensitizer during photodynamic therapy.

Anisotropy of light propagation in human skin

Using spatially resolved, steady state diffuse reflectometry, a directional dependence was found in the propagation of visible and near infrared light through human skin in vivo. The skin's reduced scattering coefficient mu(s)' varies by up to a factor of two between different directions of propagation at the same position. This anisotropy is believed to be caused by the preferential orientation of collagen fibres in the dermis, as described by Langer's skin tension lines. Monte Carlo simulations that examine the effect of partial collagen fibre orientation support this hypothesis. The observation has consequences for non-invasive diagnostic methods relying on skin optical properties, and it could be used non-invasively to determine the direction of lines of cleavage in order to minimize scars due to surgical incisions.

Monte carlo diffusion hybrid model for photon migration in a two-layer turbid medium in the frequency domain

We propose a hybrid Monte Carlo (MC) diffusion model for calculating the spatially resolved reflectance amplitude and phase delay resulting from an intensity-modulated pencil beam vertically incident on a two-layer turbid medium. The model combines the accuracy of MC at radial distances near the incident beam with the computational efficiency afforded by a diffusion calculation at further distances. This results in a single forward calculation several hundred times faster than pure MC, depending primarily on model parameters. Model predictions are compared with MC data for two cases that span the extremes of physiologically relevant optical properties: skin overlying fat and skin overlying muscle, both in the presence of an exogenous absorber. It is shown that good agreement can be achieved for radial distances from 0.5 to 20 mm in both cases. However, in the skin-on-muscle case the choice of model parameters and the definition of the diffusion coefficient can lead to some interesting discrepancies.

Modeling of photosensitizer fluorescence emission and photobleaching for photodynamic therapy dosimetry

Photon diffusion theory was used to model photobleaching and tissue necrosis resulting from broad-beam therapeutic light irradiation of tissue containing a photosensitizer. The photosensitizer fluorescence signal at the tissue surface was simulated with both broad-beam and pencil-beam excitation. The relationship between the decreasing fluorescence signal and the increasing depth of tissue photodynamic damage during treatment was examined. By analyzing spatially resolved fluorescence measured at the tissue surface in terms of an equivalent virtual point or planar source of fluorescence within the tissue, predictions of necrosis depth that are insensitive to a range of initial treatment parameters were shown to be possible. Preliminary measurements in tissue-simulating phantoms supported the main theoretical findings. The potential value and feasibility of this technique for photodynamic therapy dosimetry are discussed.

Accuracy of the diffusion approximation in determining the optical properties of a two-layer turbid medium

We have examined the possibility of determining the optical properties of a two-layer medium by using a diffusion approximation radiation transport model [Appl. Opt. 37, 779 (1998)]. Continuous-wave and frequency-domain (FD) low-noise Monte Carlo (MC) data were fitted to the model. Marquardt-Levenberg and a simulated annealing algorithm were used and compared as optimization techniques. Our particular choice of optical properties for the two-layer model was consistent with skin and underlying fat in the presence of an exogenous chromophore [Appl. Opt. 37, 1958 (1998)]. The results are therefore specific to this set of optical properties. It was found that the cw diffusion solution could never be used to estimate all optical properties reliably. The combined cw and FD solutions could not be used to estimate some of the top-layer optical properties to an accuracy of better than 10%, although the absorption and the transport scattering coefficients of the bottom layer could be estimated to within 7% and 0.5%, respectively. No improvement was found from simultaneously fitting MC data at three different modulation frequencies. These results point to the need for a more accurate radiation transfer model at small source-detector separations.

Comparison of the in vivo photodynamic threshold dose for photofrin, mono- and tetrasulfonated aluminum phthalocyanine using a rat liver model

The photodynamic threshold dose in normal rat liver was determined from the measured depth of necrosis following surface irradiation. The threshold was determined for the photosensitizing drugs Photofrin and monosulfonated aluminum chlorophthalocyanine, AlPcS1, at 24 h postinjection and was found to be (3.4 x/divided by 1.3) x 10(18) and (8.2 x/divided by 1.5) x 10(18) photons cm-3, respectively, compared with the previously reported value of (38 +/- 2) x 10(18) photons cm-3 for the tri/tetrasulfonated phthalocyanine, AlPcS4. These values were independent of drug concentration or total light fluence. For all three drugs the depth of tissue necrosis decreased as the time between drug and light administration increased from 10 min to 72 h. This decrease can be attributed both to the change in the tissue drug concentration as well as to changes in the efficiency of photodynamic therapy for producing tissue damage, related to the photodynamic necrosis threshold. The threshold values for all three photosensitizers were lowest at 10 min post injection: (1.4 x/divided by 1.4) x 10(18), (1.6 x/divided by 1.3) x 10(18) and (23 x/divided by 1.3) x 10(18) photons cm-3 for Photofrin, AlPcS1 and AlPcS4, respectively. The changes in necrosis threshold with time may be due to an initial change from entirely vascular to a combination of vascular and cellular damage, with later redistribution of the photosensitizer to targets at the subcellular level.

Influence of layered tissue architecture on estimates of tissue optical properties obtained from spatially resolved diffuse reflectometry

Most instruments used to measure tissue optical properties noninvasively employ data-analysis algorithms that rely on the simplifying assumption that the tissue is semi-infinite and homogeneous. The influence of a layered tissue architecture on the determination of the scattering and absorption coefficients has been investigated in this study. Reflectance as a function of distance from a point source for a two-layered tissue architecture that simulates skin overlying fat was calculated by using a Monte Carlocode. These data were analyzed by using a diffusion theory modelfor a homogeneous semi-infinite medium to calculate the scatter and absorption coefficients. Depending on the algorithm and the radial distance, the estimated tissue optical properties were different from those of either layer, and under some circumstances, physically impossible. In addition, the sensitivity and cross talk of the estimated optical properties to changes in input optical properties were calculated for different layered geometries. For typical optical properties of skin, the sensitivity to changes in optical properties is highly dependent on the layered architecture, the measurement distance, and the fitting algorithm. Furthermore, a change in the input absorption coefficient may result in an apparent change in the measured scatter coefficient, and a change in the in put scatter coefficient may result in an apparent change in the measured absorption coefficient.

Beta2-microglobulin in hypertensive pregnancies

Beta2-Microglobulin (beta2-m) is a polypeptide that is freely filtered and then mostly reabsorbed and degraded in the proximal renal tubule. Beta2-m is a marker of glomerular filtration (GFR) in renal failure, whereas urinary beta2-m is a marker of proximal renal tubular dysfunction. Preeclampsia (PE) (ie, de novo hypertension in pregnancy with accompanying renal, cerebral, or liver disease or thrombocytopenia) often has renal involvement characterized by proteinuria, decreasing glomerular filtration, or renal tubular dysfunction. The aim of this study was to determine whether serum beta2-m concentration or urinary beta2-m excretion were greater in women with PE than in women with gestational hypertension (GH) (ie, isolated de novo hypertension in the second half of pregnancy) and normal pregnant women. Seventy-five pregnant women (35 with PE, 22 with GH, and 18 normotensives) were studied prospectively. Serum creatinine and beta2-m concentrations, 24-hour proteinuria, and fractional excretion (FE) of beta2-m were measured. Preeclamptics had similar serum creatinine but higher serum beta2-m (3.26+/-0.99 mg/L) than gestational hypertensives (2.44+/-0.77 mg/L; P = 0.016), and both groups had higher serum beta2-m than controls (1.62+/-0.54 mg/L; P = 0.001). FE of beta2-m was similar amongst groups (PE: 0.27%; interquartile range [IQR]: 0.20-0.86; GH: 0.21%; IQR: 0.11-0.40; controls: 0.26%, IQR: 0.12-0.69). PE is characterized by higher serum beta2-m but similar serum creatinine to GH. Because FE beta2-m is similar in these groups, this implies reduced filtering of beta2-m in PE rather than altered tubular handling of beta2-m. Further studies are now necessary to assess whether measurement of serum beta2-m is helpful in the clinical management of the hypertensive disorders of pregnancy.

The expression of acylphosphatase is associated with the metastatic phenotype in human colorectal tumors

We have performed differential display comparing gene expression from cell lines derived from human colorectal tumors. The cell lines were selected for study based on their ability to form metastases following injection into athymic mice. One gene which was expressed exclusively by the metastatic lines was identified as human acylphosphatase (e.c. 3.6.1.7, acylphosphate phosphohydrolase). The expression of this gene was confirmed by RT-PCR using gene-specific primers. This gene product catalyzes the hydrolysis of phosphorylated intermediates of Na+/K(+)-ATPase and of Ca(2+)-ATPases of mammalian cells. Changes in the activity of the Na+/K(+)-ATPase pump, regulated by acylphosphatase, have been previously reported in chemically-induced colonic tumors. The differential expression of this gene in the human metastatic colorectal lines suggests it may be involved in the metastatic phenotype.

Pancreatic resection combined with intraoperative radiation therapy for pancreatic cancer

OBJECTIVE

The objective of the study was to analyze a single center's experience in the treatment of pancreatic carcinoma with a combination of pancreatic resection and intraoperative radiation therapy (IORT).

SUMMARY BACKGROUND DATA

Pancreatic cancer is the most lethal form of gastrointestinal malignancy. Historically, it carries a 20% 1-year survival and a 5-year survival of 3% to 5%. Since 1987, patients at Thomas Jefferson University Hospital have been offered IORT in an attempt to improve their survival.

METHODS

The authors reviewed all patients treated at Thomas Jefferson University Hospital with pancreatic adenocarcinoma from 1987 to 1994. From this population, 14 patients were identified who received IORT in conjunction with curative surgery. Duration of hospital stay, perioperative complications, duration of postoperative ileus, and survival were assessed by retrospective review.

RESULTS

Of the 14 patients, 6 were male and 8 were female. Patient median age was 61. Six patients had stage I disease, 2 had stage II, 6 had stage III. Two patients had total pancreatectomy, 2 had distal pancreatectomy, and the remaining had pancreaticoduodenectomy (Whipple resection). Median survival was 16 months with a 15.5% 5-year survival. Postoperative complications, duration of hospital stay, and duration of postoperative ileus were not adversely affected by the addition of IORT when compared to in-house control subjects.

CONCLUSIONS

Intraoperative radiation therapy is a useful adjunct to surgical resection as treatment of pancreatic cancer. The authors' data suggested it can prolong median survival and long-term survival without adding significant morbidity.

Correlation between blood glucose concentration in diabetics and noninvasively measured tissue optical scattering coefficient

Diabetics would benefit greatly from a device capable of providing continuous noninvasive monitoring of their blood glucose levels. The optical scattering coefficient of tissue depends on the concentration of glucose in the extracellular fluid. A feasibility study was performed to evaluate the sensitivity of the tissue reduced scattering coefficient in response to step changes in the blood glucose levels of diabetic volunteers. Estimates of the scattering coefficient were based on measurements of the diffuse reflectance on the skin at distances of 1-10 mm from a point source. A correlation was observed between step changes in blood glucose concentration and tissue reduced scattering coefficient in 30 out of 41 subjects measured.

Diaspirin cross-linked hemoglobin resuscitation of hemorrhage: comparison of a blood substitute with hypertonic saline and isotonic saline

Resuscitation with tiny volumes of hypertonic solutions rapidly restores tissue perfusion while minimizing edema after hemorrhage and tissue trauma.

METHODS

We compared an O2-carrying fluid, Diaspirin Cross-Linked Hemoglobin (DCLHb), to 7.5% NS/Dextran-70 (HTS) or 0.9% saline (NS) in a trauma (celiotomy) hemorrhage model. Anesthetized rats (n = 10/group) underwent a tracheotomy, placement of jugular vein and carotid artery catheters, and placement of an abdominal aortic flow probe. Rats were hemorrhaged (20 mL/kg) from t = 0-15 minutes, and were given NS (group I), 60 mL/kg, HTS (group II), 4 mL/kg, or DCLHb (group III), 4 mL/kg, from t = 15-30 minutes. Sampling mandated removal of an additional 10 mL/kg of blood during the 2-hour experiment.

RESULTS

Mean arterial pressure was restored after hemorrhage in all groups. Oxygen delivery, which diminished dramatically after hemorrhage, was less than baseline in all groups after resuscitation. Oxygen consumption was restored in all groups after a sharp decrease during hemorrhage. Base deficit increased in the all groups but was greatest after normal saline or hypertonic saline resuscitation (t = 120 minutes; I = 12 +/- 0.4*, II = 13 +/- 0.5* c, III = 10 +/- 0.1*; * = p < 0.05 versus baseline value within group for groups I, II, and III; c = p < 0.05 group versus DCLHb (group II), by ANOVA).

CONCLUSION

DCLHb restored mean arterial pressure and ameliorated the development of flow-dependent oxygen consumption. Base deficit, a reflection of systemic oxygen debt, was minimized with this blood substitute. DCLHb may represent a superior small volume resuscitative fluid after trauma and hemorrhage.

A diffusion theory model of spatially resolved, steady-state diffuse reflectance for the noninvasive determination of tissue optical properties in vivo

A model based upon steady-state diffusion theory which describes the radial dependence of diffuse reflectance of light from tissues is developed. This model incorporates a photon dipole source in order to satisfy the tissue boundary conditions and is suitable for either refractive index matched or mismatched surfaces. The predictions of the model were compared with Monte Carlo simulations as well as experimental measurements made with tissue simulating phantoms. The model describes the reflectance data accurately to radial distances as small as 0.5 mm when compared to Monte Carlo simulations and agrees with experimental measurements to distances as small as 1 mm. A nonlinear least-squares fitting procedure has been used to determine the tissue optical properties from the radial reflectance data in both phantoms and tissues in vivo. The optical properties derived for the phantoms are within 5%-10% of those determined by other established techniques. The in vivo values are also consistent with those reported by other investigators.

Phantom studies of triple photon absorptiometry and bone mineral measurement at a hip prosthesis

The feasibility of using triple photon absorptiometry (TPA) for the measurement of bone mineral mass about a hip prosthesis was examined. A theoretical expression describing the variance of TPA measurements was verified using a triple photon source and phantom materials which simulate the soft tissue-bone mineral-metal prosthesis system. The expression for the variance was used to determine an optimized set of photon energies. It was shown that a precision of 3% could be obtained for reasonable measurement times using this optimized set of energies, and that TPA should be a feasible approach for measurement of bone mineral about a hip prosthesis.

Coherent scattering and bone mineral measurement: the dependence of sensitivity on angle and energy

The sensitivity of a technique for the measurement of trabecular bone mineral concentration has been examined theoretically and experimentally. The technique is based on coherent gamma ray scattering and corrections for attenuation are obtained from transmitted photons rather than Compton scattered photons. For an incident photon energy of 60 keV, the minimum detectable bone mineral difference is practically independent of scattering angle while for an incident energy of 100 or 122 keV the scattering angle must be less than 70 degrees to optimize the minimum detectable difference.

Triple photon absorptiometry cannot correct for fat inhomogeneities in lumbar spine bone mineral measurements

In vivo fat inhomogeneities can cause significant errors in measurements of lumbar spine mineral mass using dual photon absorptiometry. Extension to a triple photon technique to correct for the presence of fat is not possible because of the unacceptable increase of about a factor of 3,000 required in the radiation dose to yield sufficient transmitted photons for adequate precision.

The error due to fat inhomogeneity in lumbar spine bone mineral measurements

Bone mineral mass measurements using dual photon absorptiometry rely on the assumption that fat thickness is constant within the region scanned by the photon beam. This assumption has been tested using both single and multiple slices from archived CT scans. In 26 patients, the difference in fat content between the bone and baseline measurement sites, the fat deviation, was found to vary from -2.7 to 18.7%. The median fat deviation was 4.4% which can lead to errors in measured lumbar spine bone mineral of 6 to 11%. Approximately one third of patients will have errors greater than 10%.

Effect of scintillation camera nonuniformity on ejection fraction measurements

A rotating cardiac phantom with three possible ejection fraction (EF) values was used in conjunction with a scintillation camera employing energy correction and count skim arithmetic for uniformity correction. Studies were collected with and without any correction, with the energy window of the analyzer set properly, and with the camera properly tuned. The uniformity was then degraded in one experiment by off-setting the analyzer window both high and low with respect to the primary photopeak and in another experiment by de-tuning a selected photomultiplier tube. In both experiments studies were taken with no correction enabled, and then with each of the correction options enabled. The results of both experiments show that ejection fraction values could be in error when the differential uniformity using National Electrical Manufacturers Association (NEMA) protocols exceeds 10%. If either energy correction alone, or energy correction combined with count skim correction is used, the ejection fraction values return to more acceptable values. Asymmetric windows, improper setting of the energy window or a badly tuned photomultiplier will likely result in poor analog images before the effect on ejection fraction measurements becomes evident. Uniformity correction devices do not adversely affect the numerical results obtained from these phantom studies, but should, nevertheless, be used with caution.

Open admissions, orality,aand literacy

Open admissions students tend to be highly oral. Their modes of thinking are different from the modes of thinking demanded in the highly literate (i.e., detached, objective, and scientific) world of college. They can learn the more literate modes of thinking, however, but this requires special awareness and effort on the part of their teachers. Some assumptions and instructional approaches made with traditional students cannot be made with highly oral students in a community college. Moreover, the effort to move the students into the more literate modes of thought cannot be limited to a couple of "remedial" courses in reading and writing. The promise of the open door can be realized for highly oral students only as more and more teachers change their assumptions about student learning and modify their instructional practices accordingly.