• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 161
  • 95
  • 44
  • 14
  • 8
  • 7
  • 7
  • 7
  • 7
  • 7
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 403
  • 66
  • 56
  • 44
  • 42
  • 33
  • 33
  • 32
  • 27
  • 26
  • 25
  • 23
  • 23
  • 21
  • 21
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Bat use of old growth redwood basal hollows with increasing isolation in contiguous, remnant, and legacy forest stands /

Roberts, Amy L. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2008. / Includes bibliographical references (leaves 61-67). Also available via Humboldt Digital Scholar.
42

The ecological and evolutionary implications of genetic structure and diet in the pallid bat (Antrozous pallidus)

Ingram, Katherine P. January 2007 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2007. / "December, 2007." Includes bibliographical references. Online version available on the World Wide Web.
43

The potential of using insectivorous bats (Microchiroptera) as a means of insect pest control in agricultural areas

Marais, Werner Christiaan 03 June 2010 (has links)
M.Sc. / Members of the Suborder Microchiroptera consume large numbers of insects. When large enough numbers of these bats are present in agricultural areas, the need for insecticides can be reduced significantly. The ZZ2 Tomato Farms in Mooketsi and the Secrabje Farm in Waterpoort, in the Limpopo Province were chosen as study sites. Although ZZ2 focuses on the production of tomatoes, both farms produce a variety of vegetables and fruit. These farms were chosen because the management of both have shown a commitment to conservation and attempt to minimise their impact on the environment. Bat species indigenous to the study areas were captured by means of mist nets for identification purposes. Basic morphological data of captured specimens were collected and recorded. Their roosting behaviour and preferences were studied by visiting diurnal roosts in the two study sites. Microclimatic measurements were taken in roosts occupied by Chaerephon pumilus, Mops condylurus and Taedarida aegyptiaca. Microclimatic measurements were also done in bat houses designed for the housing of bats in agricultural areas. Results suggest that other factors, additional to temperature and relative humidity, contribute to the success and probability of bat house occupancy by bats. Existing roosts in man-made structures such as roofs, can successfully be enhanced to stimulate increase in colony size. Bat activities were determined in agricultural areas and adjacent natural habitats by means of recordings of the echolocation calls of the different bat Families. These were compared to the occurrence of nocturnal flying insect orders that were captured in light traps at the same localities. Of the bat species studied, a positive correlation between increased bat activity and higher number of insects, including pest species, was found. It seems as if the Molossidae has the greatest potential to be utilised in the control of insect pests of agricultural areas in the Limpopo of the bat species studied. A holistic approach favouring insectivorous bats on farms is recommended. This can be done i.a. through the conservation of abundant areas of natural vegetation adjacent to the agricultural areas which would provide foraging for bats during winter, periods of drought or when the lands lie fallow. The excessive and injudicious use of insecticides, which has a negative effect on bats, counteracts the beneficial and cheap alternative of natural insect pest control provided by insectivorous bats.
44

PHYSIOLOGICAL ADAPTATIONS IN THE SYNDROME OF CHIROPTEROPHILY WITH EMPHASIS ON THE BAT, LEPTONYCTERIS, LYDEKKER

Howell, Donna Jeanne, 1944- January 1972 (has links)
No description available.
45

Bat Problem Management

Sullivan, Lawrence 02 1900 (has links)
5 pp. / Withdrawn 7/09
46

Batty About Bats

Gouge, Dawn, Lawaczeck, E., Snyder, J., Renison, Nancy 11 1900 (has links)
16 pp. / Bat IPM / Bats, order Chiroptera, have traditionally been maligned and misunderstood by the general public. Bats are, however, important components of the natural and urban landscape; they provide valuable pest control of public health and nuisance insects, and they serve an important role in the pollination of several of Arizona's native columnar cacti. In urban environments, particularly schools, bats are of concern due to their ability to vector the rabies virus. Consequently, the status of bats of bats in schools has become that of a pest. Integrated pest management (IPM) methods have traditionally been reserved for managing arthropods; however, the fundamental principles of urban IPM may be just as easily applied to mammals with equal success. The ecologically sensitive aspects of IPM make this a highly preferred approach in managing bats as an organism of considerable conservation concern.
47

Selected aspects of the ecology of the big brown bat (Eptesicus fuscus) in Grant County, Indiana

Landrum, Thomas W. January 1971 (has links)
Maternal colonies of the Big Brown Bat (Eptesicus fuscus) were located and studied in Delaware, Grant, Hamilton and Madison Counties, Indiana, from March 1, 1970 to June 1, 1971. A total of 602 bats was captured. These banded bats provided data on intercolony movements and longevity. Three intercolony movements were recorded, all of short distances. Two bats were recaptured which had attained a minimum age of 12 years. Further detailed data regarding population levels; age as determined by canine tooth year and wing bone ossification; sex ratios; reproductive characteristics and body weight are discussed. / Department of Biology
48

Bat assemblages in Vietnamese karst : diversity, reproduction, echolocation and ecomorphology

Furey, Neil M. January 2009 (has links)
Bat assemblages inhabiting two discrete karst areas in north Vietnam were sampled from 2006-2008.  Inventory studies indicate that Vietnamese karst areas with intact primary forest harbour a large proportion of the national bat fauna with levels of species richness which may greatly exceed those of other forest types in-country.  Forests on karst ridgetops in degraded areas are capable of supporting high bat species richness at low abundances and their persistence as linear tracts and latticeworks of forest in anthropogenic landscapes may provide corridors for the movement of forest-dependent bats.  Reproductive studies demonstrate that the timing of major reproductive events (pregnancy, lactation and weaning) coincide for two pteropodids and for 26 species in three insectivorous bat families.  The high temporal congruence in reproduction and climatic homogeneity of north Vietnam (18-23°N) suggests that these results may have wider applicability.  Echolocation studies involving 30 insectivorous species indicate that correct acoustic identification of free-flying bats is feasible.  Comparisons of conventional capture methods with simultaneous acoustic sampling in a variety of karst habitats demonstrate that acoustic methods are indispensable in maximising inventory completeness in assemblage studies.  Ecomorphological studies of 37 bat species indicate that analysis of wing morphology is useful in predicting foraging habitats.  Results support the hypothesis that bat species highly adapted to foraging in the forest interior are negatively affected by forest degradation.  Three bat species new to science are described.  Factors associated with extinction risk in bats are reviewed and recommendations for conservation management and further research are provided.
49

Finding the sweet-spot of a cricket bat using a mathematical approach

Rogers, Langton 13 September 2016 (has links)
University Of The Witwatersrand Department Of Computational And Applied Mathematics Masters’ Dissertation 2015 / The ideal hitting location on a cricket bat, the ‘sweet-spot’, is taken to be defined in two parts: 1) the Location of Impact on a cricket bat that transfers the maximum amount of energy into the batted ball and 2) the Location of Impact that transfers the least amount of energy to the batsman’s hands post-impact with the ball; minimizing the unpleasant stinging sensation felt by the batsman in his hands. An analysis of di↵erent hitting locations on a cricket bat is presented with the cricket bat modelled as a one dimensional beam which is approximated by the Euler-Lagrange Beam Equation. The beam is assumed to have uniform density and constant flexural rigidity. These assumptions allow for the Euler-Lagrange Beam Equation to be simplified considerably and hence solved numerically. The solution is presented via both a Central Time, Central Space finite di↵erence scheme and a Crank-Nicolson scheme. Further, the simplified Euler-Lagrange Beam Equation is solved analytically using a Separation of Variables approach. Boundary conditions, initial conditions and the framework of various collision scenarios between the bat and ball are structured in such a way that the model approximates a batsman playing a defensive cricket shot in the first two collision scenarios and an aggressive shot in the third collision scenario. The first collision scenario models a point-like, impulsive, perpendicular collision between the bat and ball. A circular Hertzian pressure distribution is used to model an elastic, perpendicular collision between the bat and ball in the second collision scenario, and an elliptical Hertzian pressure distribution does similarly for an elastic, oblique collision in the third collision scenario. The pressure distributions are converted into initial velocity distributions through the use of the Lagrange Field Equation. The numerical solution via the Crank-Nicolson scheme and the analytical solution via the Separation of Variables approach are analysed. For di↵erent Locations of Impact along the length on a cricket bat, a post-impact analysis of the displacement of points along the bat and the strain energy in the bat is conducted. Further, through the use of a Fourier Transform, a post-impact frequency analysis of the signals travelling in the cricket bat is performed. Combining the results of these analyses and the two-part definition of a ‘sweet-spot’ allows for the conclusion to be drawn that a Location of Impact as close as possible to the fixed-end of the cricket bat (a point just below the handle of the bat) results in minimum amount of energy transferred to the hands of the batsman. This minimizes the ‘stinging’ sensation felt by the batsman in his hands and satisfies the second part of the definition of a sweet-spot. Due to the heavy emphasis of the frequency analysis in this study, the conclusion is drawn that bat manufacturers should consider the vibrational properties of bats more thoroughly in bat manufacturing. Further, it is concluded that the solutions from the numerical Crank-Nicolson scheme and the analytical Separation of Variables approach are in close agreement.
50

THE NATURAL HISTORY OF THE CAVE BAT, MYOTIS VELIFER

Hayward, Bruce J. (Bruce Jolliffe), 1928- January 1961 (has links)
No description available.

Page generated in 0.0475 seconds