New genus of primitive wombat (Vombatidae, Marsupialia) from Miocene deposits in the Riversleigh World Heritage Area (Queensland, Australia)

Copyright Palaeontological Association, March 2015. This is an open access article, available to all readers online, published under a creative commons licensing (https://creativecommons.org/licenses/by/4.0/)

An optical fibre dynamic instrumented palpation sensor for the characterisation of biological tissue

AbstractThe diagnosis of prostate cancer using invasive techniques (such as biopsy and blood tests for prostate-specific antigen) and non-invasive techniques (such as digital rectal examination and trans-rectal ultrasonography) may be enhanced by using an additional dynamic instrumented palpation approach to prostate tissue classification. A dynamically actuated membrane sensor/actuator has been developed that incorporates an optical fibre Fabry–Pérot interferometer to record the displacement of the membrane when it is pressed on to different tissue samples. The membrane sensor was tested on a silicon elastomer prostate model with enlarged and stiffer material on one side to simulate early stage prostate cancer. The interferometer measurement was found to have high dynamic range and accuracy, with a minimum displacement resolution of ±0.4μm over a 721μm measurement range. The dynamic response of the membrane sensor when applied to different tissue types changed depending on the stiffness of the tissue being measured. This demonstrates the feasibility of an optically tracked dynamic palpation technique for classifying tissue type based on the dynamic response of the sensor/actuator

A reinvestigation of the stock price reactions to announcements of Black top executive appointments

We investigate the stock market reactions to the announcements of Black CEO and top management team (TMT) appointments in light of two conflicting studies that advance competing and opposite theories. In 2021, Gligor and colleagues theorized that reactions will be negative due to racial stereotyping, and found negative mean stock price reactions for both Black CEOs and TMTs. Conversely, in 2023, Jeong and colleagues theorized that the stock market will respond positively to the appointment of Black CEOs, because these CEOs have to meet a “higher bar” to be appointed. They reported a positive mean reaction to such appointments. In our quasi-replication of these two prior studies, we find a reliably positive mean reaction for Black CEOs but an immaterial median reaction, and no marginal stock price impact to the announcement of the appointment of a Black CEO and TMT executives after controlling for explanatory factors that go outside the racial bias and higher bar theories. In light of the fragility and lack of robustness in these results, we recommend that future research in the area of Black top executives and the stock market be cautious when presenting and interpreting results

The Parameterized Post-Friedmann Framework for Theories of Modified Gravity: Concepts, Formalism and Examples

A unified framework for theories of modified gravity will be an essential tool for interpreting the forthcoming deluge of cosmological data. We present such a formalism, the Parameterized Post-Friedmann framework (PPF), which parameterizes the cosmological perturbation theory of a wide variety of modified gravity models. PPF is able to handle spin-0 degrees of freedom from new scalar, vector and tensor fields, meaning that it is not restricted to simple models based solely on cosmological scalar fields. A direct correspondence is maintained between the parameterization and the underlying space of theories, which allows us to build up a `dictionary' of modified gravity theories and their PPF correspondences. In this paper we describe the construction of the parameterization and demonstrate its use through a number of worked examples relevant to the current literature. We indicate how the formalism will be implemented numerically, so that the dictionary of modified gravity can be pitted against forthcoming observations.Comment: 24 pages, updated to match version published in PRD. Discussion of section 4 extended. Suggestions for the busy reader are given at the end of section

Distribution of Dendritic Cells in Normal Human Salivary Glands

Dendritic cells (DC) are believed to contribute to development of autoimmune sialadenitis, but little is known about their distribution in normal salivary glands. In this study, DC were identified and their distribution was determined in normal human parotid and submandibular glands. For light microscopy, salivary gland sections were stained with H&E or immunocytochemically using antibodies to DC markers. Transmission electron microscopy (TEM) was used to evaluate the ultrastructural characteristics of DC. In H&E sections, elongated, irregularly shaped nuclei were occasionally seen in the striated and excretory duct epithelium. Immunolabeling with anti-HLA-DR, anti-CD11c and anti-S100 revealed DC with numerous processes extending between ductal epithelial cells, often close to the lumen. Morphometric analyses indicated that HLA-DR-positive DC occupied approximately 4–11% of the duct wall volume. Similar reactive cells were present in acini, intercalated ducts and interstitial tissues. TEM observations revealed cells with indented nuclei containing dense chromatin, pale cytoplasm with few organelles, and lacking junctional attachments to adjacent cells. These results indicate that DC are abundant constituents of normal human salivary glands. Their location within ductal and acinar epithelium suggests a role in responding to foreign antigens and/or maintaining immunological tolerance to salivary proteins

An investigation of gender, perceived gender-barriers to a future occupation, and academic achievement among delinquent adolescents

The current study assesses perceptions of gender-related barriers to a future occupation and its association with academic achievement among delinquent adolescents aged 12-19 years old. It was hypothesized that the perception of gender related barriers to a future occupation would have similar effects on male and female adolescents\u27 academic achievement. Data included self-reported perceived barriers to a future occupation and academic achievement. Results indicated that females and males reported similar amounts of perceived barriers to a future occupation. Regression analysis indicated the relationship between perceived barriers and academic achievement varied across gender. For males, more perceived gender-barriers were associated with lower academic achievement, whereas, for females gender-barriers did not predict academic achievement. Although our hypothesis was not supported, the findings reveal an interesting phenomenon provoking the need for further study of gender, perceived barriers, and academic outcomes in delinquent populations

The oldest fossil record of bandicoots (Marsupialia; Peramelemorphia) from the late Oligocene of Australia

Two new late Oligocene representatives of the marsupial order Peramelemorphia (bandicoots and bilbies) from the Etadunna Formation of South Australia are described here. Bulungu muirheadae sp. nov., from Zone B (Ditjimanka Local Fauna [LF]), is represented by several dentaries and isolated upper and lower molars. Bulungu campbelli sp. nov., from Zone C (Ngapakaldi LF), is represented by a single dentary and maxilla. Together, they represent the oldest fossil bandicoots described to date. Both are small (estimated body mass o

Determinants of the round-to-round returns to pre-IPO venture capital investments in U.S. biotechnology companies

I propose that pre-IPO venture-backed biotech companies offer a useful new setting through which to evaluate the relative merits of theories for why firm size and book-to-market explain variation in stock returns. This is because pre-IPO biotech firms have large and rapidly evolving growth options relative to assets-in-place. Such attributes align closely with the key features of Berk et al.’s (1999) model of the endogenous relations between growth options, optimal investment actions and expected equity returns, where firm size and book-to-market emerge as sufficient statistics for the aggregate risk of a firm’s assets-in-place. Using venture capital investments in pre-IPO U.S. biotech companies during 1992-2001, I find that equity returns between financing rounds (‘round-to-round’ returns) are reliably negatively related to firm size and positively related to book-to-market ratios. I interpret these results as being most consistent with Berk et al.’s theory, and less consistent with alternative explanations such as financial distress, behaviorally biased investors or data snooping