756 research outputs found

    Donald Redfield Griffin: the discovery of echolocation

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    The puzzle as to how bats navigate without colliding with obstacles and hunt tiny mosquitoes in complete darkness remained unanswered for nearly 140 years after Lazzaro Spallanzani, who proposed at the close of the 18th century that bats possess a 'sixth sense' for orientation. Donald Griffin solved the puzzle in 1938 with the help of world's first ultrasound microphone devised by the American physicist G W Pierce. Griffin called this sixth sense 'echolocation', which enables bats and marine mammals such as whales, dolphins and porpoises to lead active lives under the cover of darkness. In this article we describe the life of Donald Griffin and how he proved the existence of echolocation in bats

    Does Function Follow Organizational Form? Evidence From the Lending Practices of Large and Small Banks

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    Theories based on incomplete contracting suggest that small organizations may do better than large organizations in activities that require the processing of soft information. We explore this idea in the context of bank lending to small firms, an activity that is typically thought of as relying heavily on soft information. We find that large banks are less willing than small banks to lend to informationally 'difficult' credits, such as firms that do not keep formal financial records. Moreover, controlling for the endogeneity of bank-firm matching, large banks lend at a greater distance, interact more impersonally with their borrowers, have shorter and less exclusive relationships, and do not alleviate credit constraints as effectively. All of this is consistent with small banks being better able to collect and act on soft information than large banks.

    Does Function Follow Organzizational Form? Evidence From the Lending Practices of Large and Small Banks

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    Theories based on incomplete contracting suggest that small organizations may do better than large organizations in activities that require the processing of soft information. We explore this idea in the context of bank lending to small firms, an activity that is typically thought of as relying heavily on soft information. We find that large banks are less willing than small banks to lend to informationally “difficult†credits, such as firms that do not keep formal financial records. Moreover, controlling for the endogeneity of bank-firm matching, large banks lend at a greater distance, interact more impersonally with their borrowers, have shorter and less exclusive relationships, and do not alleviate credit constraints as effectively. All of this is consistent with small banks being better able to collect and act on soft information than large banks. The opinions in this paper do not necessarily reflect those of the Federal Reserve Board or its staff. This work has been supported by the National Science Foundation (Rajan, Stein), and the George J. Stigler Center for Study of the State and Economy (Rajan). Thanks also to seminar participants at Yale, the Federal Reserve Bank of New York, Tulane, Babson, the University of Illinois, the Federal Reserve Bank of Chicago Bank Structure Conference, the NBER and the Western Finance Association meetings, as well as to Abhijit Banerjee, Michael Kremer, David Scharfstein, Andrei Shleifer, Greg Udell, Christopher Udry and James Weston for helpful comments and suggestions.

    Postnatal growth, age estimation and development of foraging behaviour in the fulvous fruit bat Rousettus leschenaulti

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    This study documents the postnatal growth, age estimation and development of the foraging behaviour of the fulvous fruit batRousettus leschenaulti under captive conditions. At birth, the young were naked and pink with closed eyes and folded pinnae. By day four of age, their eyes had opened and the pups began to move. The mean length of forearm in 5-day-old pups was 24.9 mm and body mass was 10.8 g, equivalent to 32.3% and 14.2% of the values from postpartum females. The length of forearm and body mass increased linearly until 45 and 50 days, respectively, and thereafter maintained an apparent stability. The epiphyseal gap of the fourth metacarpal-phalangeal joint increased until 15 days, then decreased linearly until 75 days and thereafter closed. Age was estimated quantitatively, based on linear changes observed in the length of the forearm and epiphyseal gap. Pups began to roost separately, but adjacent to their mothers when 30 days old and flew clumsily when they were about 40 days old. After attaining clumsy flight, the young bats made independent foraging attempts feebly by biting and licking small fruit pieces. Young bats were engaged in suckling as well as ingesting fruits when they were about 50 days old. Between 55 and 65 days, they flew well and fed on fruits. At the age of 75 days, the young bats were completely weaned and at two months, their foraging behaviour was similar to that of their mothers. There was no significant difference in the growth pattern of the young maintained in captivity compared with those under natural conditions

    Bat pollination of kapok tree, Ceiba pentandra

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    Two species of pteropodid bats Cynopterus sphinx and Pteropus giganteus visited inflorescences of kapok trees, Ceiba pentandra through the night. A third species, Rousettus leschenaulti infrequently visited the inflorescences. Both C. sphinx and P. giganteus foraged in groups and there were temporal variations in their visits to the trees. The ventral body surfaces of the bats were covered with pollen grains when they landed on the inflorescences to lap up the nectar. In addition to bats, moths also visited the inflorescences. Bat and insectexclusion experiments were performed to study their pollination efficiency. Bats were more efficient in pollinating flowers of C. pentandra than other pollinators like insects

    Focal Epithelial Hyperplasia: A Rare Case Report

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    Focal epithelial hyperplasia is a rare entity of oral mucosa induced by Human Papilloma virus type 13 and 32. It was described by Estrada in 1956 within a group of Colombian Caramanda Indians. In Latin America it is called Multifocal Papilloma virus induced epithelial hyperplasia. It is common in younger age groups. Generally it is very rare in Asia. Here we report a case of 32 year old male who came with a complaint of burning sensation for past 6 months. The lesion was diagnosed as Focal epithelial hyperplasia according to clinical and Histopathological features. Dental clinicians should be aware of these lesions with a careful clinical and Histopathological observation under definitive diagnosis

    Feeling our way: academia, emotions and a politics of care

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    This paper aims to better understand the role of emotions in academia, and their part in producing, and challenging, an increasingly normalized neoliberal academy. It unfolds from two narratives that foreground emotions in and across academic spaces and practices, to critically explore how knowledges and positions are constructed and circulated. It then moves to consider these issues through the lens of care as a political stance towards being and becoming academics in neoliberal times. Our aim is to contribute to the burgeoning literature on emotional geographies, explicitly bringing this work into conversation with resurgent debates surrounding an ethic of care, as part of a politic of critiquing individualism and managerialism in (and beyond) the academy. We consider the ways in which neoliberal university structures circulate particular affects, prompting emotions such as desire and anxiety, and the internalisation of competition and audit as embodied scholars. Our narratives exemplify how attendant emotions and affect can reverberate and be further reproduced through university cultures, and diffuse across personal and professional lives. We argue that emotions in academia matter, mutually co-producing everyday social relations and practices at and across all levels. We are interested in their political implications, and how neoliberal norms can be shifted through practices of caring-with
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