Researchers of time series cross-sectional data regularly face the change-point problem, which requires them to discern between significant parametric shifts that can be deemed structural changes and minor parametric shifts that must be considered noise. In this paper, we develop a general Bayesian method for change-point detection in high-dimensional data and present its application in the context of the fixed-effect model. Our proposed method, hidden Markov Bayesian bridge model, jointly estimates high-dimensional regime-specific parameters and hidden regime transitions in a unified way. We apply our method to Alvarez, Garrett, and Lange’s (1991, American Political Science Review 85, 539–556) study of the relationship between government partisanship and economic growth and Allee and Scalera’s (2012, International Organization 66, 243–276) study of membership effects in international organizations. In both applications, we found that the proposed method successfully identify substantively meaningful temporal heterogeneity in parameters of regression models.

In deep geological repositories, compacted bentonites have been proposed for use as barrier materials for isolating nuclear waste. The prevailing thermo-hydro-mechanical boundary conditions in the repositories may affect the swelling capacity and permeability of the compacted bentonites. In this study, the effect of preliminary desiccation on the subsequent hydro-mechanical behaviour (swelling pressure and hydraulic conductivity) of compacted Calcigel bentonite was investigated experimentally at 22°C and 80°C. In the first stage of the test, the compacted specimens were subjected to suction-controlled desiccation at 22°C and 80°C using the vapour-equilibrium technique. After the water content reached equilibrium at a given suction, the axial, radial and volumetric shrinkage strains were measured. Afterwards, constant-volume swelling-pressure tests were performed on the desiccated specimens (second test stage) by saturating the dried specimens with deionized water at 22°C and 80°C. At the end of the swelling-pressure test, the hydraulic conductivities of four saturated specimens were measured at each temperature. The volumetric shrinkage strain of the compacted bentonite during desiccation is controlled by suction instead of temperature. In addition, the preliminary desiccation increases both the swelling pressure and hydraulic conductivity of compacted bentonite, particularly if compacted bentonite undergoes extreme desiccation at an applied suction of >700 MPa.

The increased accessibility of soft-tissue data through diffusible iodine-based contrast-enhanced computed tomography (diceCT) enables comparative biologists to increase the taxonomic breadth of their studies with museum specimens. However, it is still unclear how soft-tissue measurements from preserved specimens reflect values from freshly collected specimens and whether diceCT preparation may affect these measurements. Here, we document and evaluate the accuracy of diceCT in museum specimens based on the soft-tissue reconstructions of brains and eyes of five bats. Based on proxies, both brains and eyes were roughly 60% of the estimated original sizes when first imaged. However, these structures did not further shrink significantly over a 4-week staining interval, and 1 week in 2.5% iodine-based solution yielded sufficient contrast for differentiating among soft-tissues. Compared to six “fresh” bat specimens imaged shortly after field collection (not fixed in ethanol), the museum specimens had significantly lower relative volumes of the eyes and brains. Variation in field preparation techniques and conditions, and long-term storage in ethanol may be the primary causes of shrinkage in museum specimens rather than diceCT staining methodology. Identifying reliable tissue-specific correction factors to adjust for the shrinkage now documented in museum specimens requires future work with larger samples.

The present study determined the mineralogy and thermal properties of kaolin from Acoculco (Puebla), at the eastern Trans-Mexican Volcanic Belt and compared it with the nearby deposits of Agua Blanca (Hidalgo) and Huayacocotla (Veracruz). The mineralogy of the kaolins was determined by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. Thermal behaviour was studied by differential thermal analysis, dilatometry and hot-stage microscopy. The Acoculco deposit is composed mainly of kaolinite and SiO2 minerals. In the case of Agua Blanca and Huayacocotla, alunite is abundant in places and minor anatase is also present locally. The Acoculco kaolins are Fe-poor and relatively rich in some potentially toxic elements (Zr, Sb, Pb). They undergo a relatively small amount of shrinkage (∼3–4 vol.%), during firing at 20–1300°C and cooling down to 20°C, except when >10 wt.% alunite is present. These kaolins are a suitable raw material for the ceramics industry. Other applications (pharmaceuticals, cosmetics) would require an enrichment process to eliminate impurities such as Fe oxides.

Two methods are especially suited for tomographic imaging with histological detail of macroscopic samples that consist of multiple tissue types (bone, muscle, nerve or fat): Light sheet (based) fluorescence microscopy (LSFM) and micro-computed tomography (micro-CT). Micro-CT requires staining with heavy chemical elements (and thus fixation and sometimes dehydration) in order to make soft tissue imageable when measured alongside denser structures. LSMF requires fixation, decalcification, dehydration, clearing and staining with a fluorescent dye. The specimen preparation of both imaging methods is prone to shrinkage, which is often not mentioned, let alone quantified. In this paper the presence and degree of shrinkage are quantitatively identified for the selected preparation methods/stains. LSFM delivers a volume shrinkage of 17% for bone, 56% for muscle and 62% for brain tissue. The three most popular micro-CT stains (phosphotungstic acid, iodine with potassium iodide, and iodine in absolute ethanol) deliver a volume shrinkage ranging from 10 to 56% for muscle and 27–66% for brain, while bone does not shrink in micro-CT preparation.

Laboratory studies have shown that Antarctic krill (Euphausia superba) shrink if maintained in conditions of low food availability. Recent studies have also demonstrated that E. superba individuals may be shrinking in the field during winter. If krill shrink during the winter, conclusions reached by length-frequency analysis may be unreliable because smaller animals may not necessarily be younger animals. In this study, the correlation between the body-length and the crystalline cone number of the compound eye was examined. Samples collected in the late summer show an apparent linear relationship between crystalline cone number and body-length. From a laboratory population, it appears that when krill shrink the crystalline cone number remains relatively unchanged. If crystalline cone number is little affected by shrinking, then the crystalline cone number may be a more reliable indicator of age than body-length alone. The ratio of crystalline cone number to body-length offers a method for detecting the effect of shrinking in natural populations of krill. On the basis of the crystalline cone number count, it appears from a field collection in early spring that E. superba do shrink during winter.