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The Lawson's Classroom Test of Scientific Reasoning (LCTSR) is a popular instrument that measures the development of students' scientific reasoning skills. The instrument has a two-tier question design, which has led to multiple ways of scoring and interpretation. In this research, a method of pattern analysis was proposed and applied to analyze two-tier item pairs on the subskill of Control-of-Variable (COV) of LCTSR. The data were collected from students in grade 4 through college in both the United States and China. Students' response patterns to two combined item pairs were analyzed and compared against students at different grade levels and reasoning development levels. Six performance levels were established based on students' response patterns, serving as indicators of COV reasoning development levels. With the new method, a relation was obtained between students' level of COV skills and grade level, as well as their level of overall reasoning development. It can provide useful information on the possible developmental levels of students' reasoning skills.

Simple Summary: Leptotrombidium imphalum (a chigger species) can serve as a transmitting vector of scrub typhus. Based on the field investigation in southwest China from 2001 to 2022, this article presents the first report on the distribution and infestation of L. imphalum on small mammals in the region. A total of 2161 L. imphalum were identified from 218 small mammal hosts that crossed three orders, and the majority of the mites were found on the order Rodentia (rodents). Different host species had different susceptibility to the infestation of L. imphalum, and the shrew gymnure (Neotetracus sinensis) was much more susceptible to the infestation than other host species. Leptotrombidium imphalum exhibited an aggregated distribution among different individuals of its hosts. The positive correlation between the infestation indices for L. imphalum on small mammals and the occurrence of scrub typhus, together with the low host specificity of the mite, indicates the potential risk of the mite. Leptotrombidium imphalum is a species of chigger mites, and it can serve as a transmitting vector of scrub typhus. Southwest China is an important focus of scrub typhus. Based on the field investigation in southwest China from 2001 to 2022, this article presents the first report on the distribution and infestation of L. imphalum on rodents and other sympatric small mammals in the region. A total of 2161 L. imphalum were identified from 218 small mammal hosts in 21 of 114 survey sites. The 17 host species of L. imphalum crossed 13 genera and 5 families in 3 orders (Rodentia, Eulipotyphla, and Scandentia), indicating the low host specificity of the mite. The Asian house rat (Rattus tanezumi) was the dominant host species in the 21 sites where L. imphalum were collected, and 49.38% of mites were found on R. tanezumi. Different small mammals had different susceptibility to the infestation of L. imphalum. The prevalence (PM = 27.66%), infestation mean abundance (MA = 6 mites/per examined host), and mean intensity (MI = 21.69 mites/per infested host) for L. imphalum on the shrew gymnure (Neotetracus sinensis) were much higher than those on other host species (p < 0.05), indicating N. sinensis had a high susceptibility to the infestation of L. imphalum. The infestation indices for L. imphalum on small mammal hosts varied along different altitude and latitude gradients (p < 0.05), indicating the environmental heterogeneity of the mite infestation. Leptotrombidium imphalum exhibited an aggregated distribution among different individuals of its hosts. Besides the low host specificity of L. imphalum, the prevalence of the mite was positively correlated with the occurrence of scrub typhus, indicating the potential risk of the mite. [ABSTRACT FROM AUTHOR]