The emergence of lithic technology by ∼2.6 million years ago (Ma) is often interpreted as a correlate of increasingly recurrent hominin acquisition and consumption of animal remains. Associated faunal evidence, however, is poorly preserved prior to ∼1.8 Ma, limiting our understanding of early archaeological (Oldowan) hominin carnivory. Here, we detail three large well-preserved zooarchaeological assemblages from Kanjera South, Kenya. The assemblages date to ∼2.0 Ma, pre-dating all previously published archaeofaunas of appreciable size. At Kanjera, there is clear evidence that Oldowan hominins acquired and processed numerous, relatively complete, small ungulate carcasses. Moreover, they had at least occasional access to the fleshed remains of larger, wildebeest-sized animals. The overall record of hominin activities is consistent through the stratified sequence – spanning hundreds to thousands of years – and provides the earliest archaeological evidence of sustained hominin involvement with fleshed animal remains (i.e., persistent carnivory), a foraging adaptation central to many models of hominin evolution.
OBJECTIVE -To evaluate the probability of wound healing based on percentage of wound area reduction (PWAR) at 1 and 4 weeks in individuals with large, chronic, nonischemic diabetic foot wounds following partial foot amputation.METHODS -Data from a 16-week randomized clinical trial (RCT) of 162 patients were analyzed to compare outcomes associated with negative-pressure wound therapy (NPWT) delivered through the V.A.C. Therapy System (Kinetic Concepts, San Antonio, TX) (n ϭ 77) versus standard moist wound therapy (MWT) (n ϭ 85). The 1-and 4-week regression models included 153 and 129 of the RCT patients, respectively.RESULTS -Early changes in PWAR were predictive of final healing at 16 weeks. Specifically, wounds that reached Ն15% PWAR at 1 week or Ն60% PWAR at 4 weeks had a 68 and 77% (respectively) probability of healing vs. a 31 and 30% probability if these wound area reductions were not achieved. Patients receiving NPWT were 2.5 times more likely to achieve both a 15% PWAR at 1 week and a 60% area reduction at 1 month (odds ratios 2.51 and 2.49, respectively) compared with those receiving MWT.CONCLUSION -Results of this study suggest that clinicians can calculate the PWAR of a wound as early as 1 week into treatment to predict the likelihood of healing at 16 weeks. This might also assist in identifying a rationale to reevaluate the wound and change wound therapies.
Diabetes Care 31:26-29, 2008
Clinical trials allow researchers to draw conclusions about the effectiveness of a treatment. However, the statistical analysis used to draw these conclusions will inevitably be complicated by the common problem of attrition. Resorting to ad hoc methods such as case deletion or mean imputation can lead to biased results, especially if the amount of missing data is high. Multiple imputation, on the other hand, provides the researcher with an approximate solution that can be generalized to a number of different data sets and statistical problems. Multiple imputation is known to be statistically valid when n is large. However, questions still remain about the validity of multiple imputation for small samples in clinical trials. In this paper we investigate the small-sample performance of several multiple imputation methods, as well as the last observation carried forward method.
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