Advances in optical engineering for future telescopes

Significant optical engineering advances at the University of Arizona are being made for design,fabrication,and con-struction of next generation astronomical te...     

The comparative value of serum thyroglobulin measurements and iodine 131 total body scans in the follow-up study of patients with treated differentiated thyroid cancer

This study is an attempt to unify the evaluation of patients with well-differentiated thyroid cancer after ablative therapy. As such serum thyroglobulin determinations on and off thyroid hormone (T4) therapy and iodine 131 total body scans were examined in 53 patient studies. No metastases were found in patients whose thyroglobulin value was undetectable (less than 1 ng/ml). Values during T4 therapy that were detectable, even as low as 4.2 ng/ml, were occasionally associated with metastases. After T4 withdrawal, thyroglobulin value and scan were obtained. Neither metastasis nor clinically detectable cancer was found in patients whose thyroglobulin value was less than 10 ng/ml while off T4. Conversely, a value greater than 10 ng/ml was often associated with documented metastases even when the scan was negative. In summary, a thyroglobulin value less than 1 ng/ml during T4 therapy or less than 10 ng/ml off T4 therapy suggests successful therapy and a routine scan could be avoided unless clinically indicated. However, a value greater than 10 ng/ml suggests the presence of metastasis despite a negative scan. Thyroglobulin determination substantially improves the management of these patients.     

Ping-pong ball plombage for right postpneumonectomy syndrome in children

BACKGROUND/PURPOSE: Right postpneumonectomy syndrome is a rare complication of pneumonectomy characterized by exertional dyspnea resulting from mediastinal shift into the empty hemithorax. Historically, this problem has been treated with thoracoplasty, muscle flap transposition, pericardial fixation, and plombage using a variety of materials. Significant postoperative complications have been reported with each of these methods. In an effort to avoid the problems known to be associated with other plombage materials, we have used sterilized ping-pong balls as plombage to treat the postpneumonectomy syndrome. METHODS: Two children with pneumonectomy syndrome were treated with ping-pong ball plombage. RESULTS: Symptoms improved immediately in both patients and postoperative chest x-rays in each showed a normal cardiac position. Neither child had a postoperative complication. Six-year follow-up chest films in both children have demonstrated some fluid filling of the ping-pong balls, but no clinical problems attributable to them have been noted. CONCLUSION: The authors conclude that ping-pong ball plombage appears to be a viable management option in children with right postpneumonectomy syndrome.     

Elementary Subtraction.

Four experiments examined performance on the 100 "basic facts" of subtraction and found a discontinuous "stair step" function for reaction times and errors beginning with 11 - n facts. Participants' immediate retrospective reports of nonretrieval showed the same pattern in Experiment 3. The degree to which elementary subtraction depends on working memory (WM) was examined in a dual-task paradigm in Experiment 4. The reconstructive processing used with larger basic facts was strongly associated with greater WM disruption, as evidenced by errors in the secondary task: this was especially the case for participants with lower WM spans. The results support the R. S. Siegler and E. Jenkins (1989) distribution of associations model, although discriminating among the alternative solution processes appears to be a serious challenge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differentiation between melt and freeze stages of the melt cycle using SSM/I channel ratios

Microwave remote sensing detection of snow melt and ablation generally focuses on the detection of liquid moisture in the snow-pack. For ablation estimation, it is important to determine if wet snow is in the process of melting or freezing. The different stages of the melt cycle are observed in the diurnal variation of T/sub b/ measurements from the Special Sensor Microwave Imager (SSM/I) over Greenland. SSM/I channel ratios exhibit patterns indicating that they are sensitive to melt and freeze stages of the daily melt cycle. The horizontal to vertical polarization ratio is sensitive to surface wetness associated with melting. The 19-37-GHz frequency ratio is sensitive to a frozen surface layer over wet snow which is associated with the freeze stage of the melt cycle. These observations are supported by conceptual models presented here and in in situ measurements from other investigators.     

Telling stories: The perils and promise of using verbal reports to study math strategies.

The problem size effect in adult arithmetic performance is generally attributed to direct retrieval processes operating on a network representation in long-term memory. J. LeFevre and her colleagues (J. LeFevre, J.Bisanz, et al, see record 1996-05632-004; J. LeFevre, G. S. Sadesky, and J. Bisanz, see record 1996-02680-013) challenged this explanation using verbal report evidence that adults also use time consuming nonretrieval strategies to solve simple addition and multiplication. The authors replicated J. LeFevre and colleagues' methods, but added instructional biasing and silent control conditions to test these methods. Both reaction time and report results suggest that LeFevre and colleagues' conclusions about nonretrieval frequency may have been influenced by instructions that revealed the experimental hypothesis and affected participants' strategy reports. Obtaining evidence about adult strategy use in simple arithmetic will require understanding instructional demand and appropriate report methodology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Balloon extraction of esophageal foreign bodies in children

A study to determine the sensitivity, specificity, and positive and negative predictive values of several clinical diagnostic tests of subcutaneous Achilles tendon rupture was performed during a 13-year period. There were 174 patients with clinical diagnosis of unilateral complete subcutaneous Achilles tendon tear and 28 patients with unilateral suspected but no actual Achilles tendon tear. The following tests were used: palpation, calf squeeze, Matles, Copeland, and O'Brien. Palpation of the gap was the least sensitive clinical test with the patient awake (0.73), increasing to 0.81 when the test was performed under anesthesia; the Copeland and O'Brien tests showed a sensitivity of 0.8. Both the calf squeeze and Matles tests were significantly more sensitive than the other tests (0.96 and 0.88, respectively; 0.022 < P < 0.05). All tests showed a high positive predictive value, with no statistically significant difference between the various tests. In the 28 patients with no evidence of a subcutaneous Achilles tendon tear on imaging, the tests showed a high capability to detect that the Achilles tendon was intact (gap palpation specificity, 0.89; calf squeeze test specificity, 0.93; Matles test specificity, 0.85). Whichever tests were performed, at least two of them were positive for a subcutaneous tear of the Achilles tendon in all patients in this study.     

Survival after necrotizing enterocolitis in infants weighing less than 1,000 g: 25 years' experience at a single institution

Necrotizing enterocolitis (NEC) primarily affects premature newborns. Regional and national decreases in the mean birthweight and gestational age of neonatal intensive care unit (NICU) admissions prompted a review of NEC in VLBW (very low birth weight, defined as < 1,000 g) infants in our institution over a 25-year period. There were 266 patients treated for NEC during the study interval. We compared 71 VLBW with 195 non-VLBW infants and found that VLBW infants were: fed later (6.4 days v 4.1 days, P = .009), developed NEC later (20.8 days v 13.1 days, P = .002), had significantly lower 1- and 5-minute Apgar scores, were more likely to require surgery (51% v 34%, P = .016), more often had panintestinal (defined as > 75% of intestinal length) involvement (10% v 4%, P = .043), and had poorer survival (56% v 72%, P = .013). Overall survival after NEC has improved over the study interval, both in our series and in other reports. However, the increasing number of VLBW infants who have NEC represent a subgroup who appear to be generally more ill, develop NEC later, require surgery with greater frequency than their non-VLBW counterparts, and are less likely to survive.     

Effects of in vivo cocaine administration on human platelet aggregation

Tc-99m-DTPA captopril scintigraphy was performed in a patient with suspected renovascular hypertension. Markedly impaired right renal function (Glomerular filtration rate (GFR) values for the right kidney = 14 ml/min, left kidney = 79 ml/min) was detected in the initial captopril study. Only lower pole activity of the right kidney was observed during the whole study. Since prior ultrasonographic examinations have shown bilateral normal kidney parenchyma, branch stenosis of the right upper pole was suspected. Besides significant function improvement in the following baseline study (GFR values for the right kidney = 59 ml/min, left kidney = 79 ml/min), the right kidney, this time normally shaped, was visibly higher positioned. Because of the possibility of mobile kidney and/or branch stenosis, the patient underwent selective renal angiography. A long pediculed right kidney without renal artery stenosis was found. The final diagnosis was essential hypertension. Kidney position anomalies could influence the reliability of the captopril scintigraphy, particularly when a theoretical kidney depth formula is employed for the attenuation correction.