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The final effort of the CLIMAP project was a study of the last interglaciation, a time of minimum ice volume some 122,000 yr ago coincident with the Substage 5e oxygen isotopic minimum. Based on detailed oxygen isotope analyses and biotic census counts in 52 cores across the world ocean, last interglacial sea-surface temperatures (SST) were compared with those today. There are small SST departures in the mid-latitude North Atlantic (warmer) and the Gulf of Mexico (cooler). The eastern boundary currents of the South Atlantic and Pacific oceans are marked by large SST anomalies in individual cores, but their interpretations are precluded by no-analog problems and by discordancies among estimates from different biotic groups. In general, the last interglacial ocean was not significantly different from the modern ocean. The relative sequencing of ice decay versus oceanic warming on the Stage 6/5 oxygen isotopic transition and of ice growth versus oceanic cooling on the Stage 5e/5d transition was also studied. In most of the Southern Hemisphere, the oceanic response marked by the biotic census counts preceded (led) the global ice-volume response marked by the oxygen-isotope signal by several thousand years. The reverse pattern is evident in the North Atlantic Ocean and the Gulf of Mexico, where the oceanic response lagged that of global ice volume by several thousand years. As a result, the very warm temperatures associated with the last interglaciation were regionally diachronous by several thousand years. These regional lead-lag relationships agree with those observed on other transitions and in long-term phase relationships; they cannot be explained simply as artifacts of bioturbational translations of the original signals.
Skin care practices for radiotherapy patients are complicated by dosimetric concerns. This study measures the effect on skin dose of various topical agents and dressings.
Materials and methods
Superficial doses were measured under 17 topical agents and dressings and three clinical materials for reference. Dose was measured using a MOSFET detector under a 1 mm polymethyl methacrylate slab, with 6 MV photon beams at 100 cm source to surface distance.
Results
Relative skin dose under reference materials was 128% (thermoplastic mask), 158% (5 mm bolus) and 171% (10 mm bolus). Under a realistic application of topical agent (0·5 mm), relative skin doses were 106–111%. All dry dressings yielded relative dose of ≤111%; two wet dressings yielded higher relative doses (133 and 141%).
Conclusions
Under clinically relevant conditions, no cream, gel or dry dressing increased the skin dose beyond that seen with a thermoplastic mask. Dressings soaked with water produced less skin dose than 5 mm bolus. This may be unacceptable if wet dressings are in place for the majority of the treatment course. Our results suggest that skin care practices should not be limited by dosimetric concerns when using a 6 MV photon beam.
Determine whether daily bathing with chlorhexidine-based soap decreased methicillin-resistant Staphylococcus aureus (MRSA) transmission and intensive care unit (ICU)-acquired S. aureus infection among ICU patients.
Design.
Prospective pre-post-intervention study with control unit.
Setting.
A 1,250-bed tertiary care teaching hospital.
Patients.
Medical and surgical ICU patients.
Methods.
Active surveillance for MRSA colonization was performed in both ICUs. In June 2005, a chlorhexidine bathing protocol was implemented in the surgical ICU. Changes in S. aureus transmission and infection rate before and after implementation were analyzed using time-series methodology.
Results.
The intervention unit had a 20.68% decrease in MRSA acquisition after institution of the bathing protocol (12.64 cases per 1,000 patient-days at risk before the intervention vs 10.03 cases per 1,000 patient-days at risk after the intervention; β, −2.62 [95% confidence interval (CI), −5.19 to −0.04]; P = .046). There was no significant change in MRSA acquisition in the control ICU during the study period (10.97 cases per 1,000 patient-days at risk before June 2005 vs 11.33 cases per 1,000 patient-days at risk after June 2005; β, −11.10 [95% CI, −37.40 to 15.19]; P = .40). There was a 20.77% decrease in all S. aureus (including MRSA) acquisition in the intervention ICU from 2002 through 2007 (19.73 cases per 1,000 patient-days at risk before the intervention to 15.63 cases per 1,000 patient-days at risk after the intervention [95% CI, −7.25 to −0.95]; P = .012)]. The incidence of ICU-acquired MRSA infections decreased by 41.37% in the intervention ICU (1.96 infections per 1,000 patient-days at risk before the intervention vs 1.15 infections per 1,000 patient-days at risk after the intervention; P = .001).
Conclusions.
Institution of daily chlorhexidine bathing in an ICU resulted in a decrease in the transmission of S. aureus, including MRSA. These data support the use of routine daily chlorhexidine baths to decrease rates of S. aureus transmission and infection.
Patient teaching in radiation therapy may include restrictions on applying skin products owing to concerns that the presence of such materials may increase skin dose. These restrictions may create unnecessarily complicated and conflicting self-care instructions.
Purpose
To determine what thickness of skin product is necessary to produce a clinically meaningful dose increase to the skin, and provide recommendations for evidence-based patient instructions.
Methods
Dosimetric measurements and Monte Carlo simulations were used to calculate skin dose under 0–1·5 mm thicknesses of two common classes of skin product for a variety of treatment geometries. The thickness of product required to produce a clinically significant dose increase to the skin was determined.
Results
The thickness of product required to create a clinically meaningful dose increase was >0·7 mm for 10 × 10 cm2 fields and >1·5 mm for 1 × 1 cm2 fields. A typical application of product would be only 0·3 mm.
Conclusion
It seems unrealistic to anticipate patients using sufficiently large quantities of skin product to be of clinical concern. We therefore recommend that there are no dosimetric reasons to restrict the use of these types of skin products during radiation therapy for common treatment scenarios.
Limited data on the risk of peripherally inserted central venous catheter-associated bloodstream infections (PICC BSIs) in hospitalized patients are available. In 2007, dedicated intravenous therapy nurses were no longer available to place difficult peripheral intravenous catheters or provide PICC care Barnes-Jewish Hospital.
Objectives.
To determine the hospital-wide incidence of PICC BSIs and to assess the effect of discontinuing intravenous therapy service on PICC use and PICC BSI rates.
Setting.
A 1,252-bed tertiary care teaching hospital.
Methods.
A 31-month retrospective cohort study was performed. PICC BSIs were defined using National Healthcare Safety Network criteria.
Results.
In total, 163 PICC BSIs were identified (3.13 BSIs per 1,000 catheter-days). PICC use was higher in intensive care units (ICUs) than non-ICU areas (PICC utilization ratio, 0.109 vs 0.059 catheter-days per patient-day for ICU vs non-ICU; rate ratio [RR], 1.84 [95% confidence interval {CI}, 1.78-1.91]). PICC BSI rates were higher in ICUs (4.79 vs 2.79 episodes per 1,000 catheter-days; RR, 1.7 [95% CI, 1.10-2.61]). PICC use increased hospital-wide after the intravenous therapy service was discontinued (0.049 vs 0.097 catheter-days per patient-day; P = .01), but PICC BSI rates did not change (2.68 vs 3.63 episodes per 1,000 catheter-days; P = .06). Of PICC BSIs, 73% occurred in non-ICU patients.
Conclusions.
PICC use and PICC BSI rates were higher in ICUs; however, most of the PICC BSIs occurred in non-ICU areas. Reduction in intravenous therapy services was associated with increased PICC use across the hospital, but PICC BSI rates did not increase.
The Beveridge–Nelson decomposition calculates trend and cycle for an integrated time series. However, there are two ways to interpret the results from the decomposition. One interpretation is that the optimal long-run forecast (minus any deterministic drift) used to calculate the Beveridge–Nelson trend corresponds to an estimate of an unobserved permanent component. The other interpretation is that the optimal long-run forecast defines an observable permanent component. This paper examines some issues surrounding these two interpretations and provides empirical support for interpreting the Beveridge–Nelson trend as an estimate when considering macroeconomic data.
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