One reason why ticks are considered to be arachnids is because they do not have antennae like insects do. Ticks suck blood from animals and are sometimes difficult to remove from the host's skin.
Fly on a leaf
Flies are insects that eat dead plant and animal material. Their ingestion and digestion of detritus leads to respiration and excretion of important nutrients back into the soil and water.
3D Global Methane
An animation of the three-dimensional structure of global methane evolving over time, from a global data assimilation model
Arctic Ozone from February 1, 2003 through March 30, 2003
This visualization shows the northern hemisphere ozone hole from February 1, 2003 through March 30, 2003.
West Africa Dust Storms
On the Coast of West Africa, dust storms are a common occurrence, if you take a look at this one, its about the size of Spain.
Annually Occurring Aerosol Features: Biomass Burning in Southern Africa from July to September 1986
Aerosol index over Africa from July 2, 1986 through September 7, 1986 as measured by the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS)
Annually Occurring Aerosol Features: Biomass Burning in South America from August through September
Aerosol index over South America from August 1, 1987 through September 30, 1987 as measured by the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS)
High Resolution 2-D Numerical Simulation of Emergence of Magnetic Flux Through the Solar Atmosphere
This series of animations (animations 107, 1416, 1417, and 1418) show sheets of magnetic flux undergoing velocity perturbations. The conditions for each simulation are outlined within the video.
A 3-Dimensional Model of the Magnetosphere (WMS)
The earths magnetosphere protects the earth from high-energy charged particles coming from the sun. Some charged particles are deflected by the magnetosphere, while others become trapped and produce the aurora. This presentation shows a 3-dimensional model of the magnetosphere. The features that it highlights are flat ribbons representing the paths of charged particles deflected by the magnetosphere, triangular ribbons representing magnetic field lines, and colored surfaces representing constant
North America NDVI 1993 August
NDVI in North America for August 1993, based off data collected over the 1981-2000 time frame.
Ozone Measurements from 2000 through 2003 (WMS)
This visualization shows the total ozone concentrations for the Earth from January 1, 2000 through December 31, 2003, as measured by the Toms instrument on the Earth Probe satellite. Low ozone (less than 200 Dobson units) is depicted as regions of dark blue, with high ozone (greater that 330 Dobson units) depicted as yellow and red. The most visible and dynamic feature of the ozone distribution is the ozone hole that forms over Antarctica during September of each year. The amount of ozone in the
Ethics of Human Subject Research
Ethics of Human Subject Research (2 credits) is offered by the Department of Health Policy and Management and the Distance Education Division, Johns Hopkins Bloomberg School of Public Health and The Phoebe R. Berman Bioethics Institute, Johns Hopkins University. The course introduces students to the ethics of human subject research. Ethical theory and principles are introduced, followed by a brief history of research ethics. Topics covered in lectures and moderated discussions include informed c
The History of Public Health
In the History of Public Health we will examine the historical experience of health and illness from a population perspective. This material seeks to reveal how the organization of societies facilitates or mitigates the production and transmission of disease. It also asks how do populations and groups of individuals go about securing their health? One key theme is the medical management of space in one form or another - from the public space of the environment through institutional spaces such a
Introduction to Economics
Introduction to Economics is designed to build an understanding of economic institutions, history, and principles. In addition, it will focus on relationship between private and public sectors of the U.S. economy. Also, it will analyze major economic institutions, such as property rights, markets, business organizations, labor unions, money and banking, trade, and taxation.
Space Propulsion, Spring 2004
Reviews rocket propulsion fundamentals. Discusses advanced concepts in rocket propulsion ranging from chemical engines to electrical engines. Topics include: advanced mission analysis, physics and engineering of microthrusters, solid propellant rockets, electrothermal, electrostatic, and electro-magnetic schemes for accelerating propellant. Some coverage is given of satellite power systems and their relation to propulsion systems. Space Propulsion begins with a review of rocket propulsion fundam
4.3 Live fast, die young Both the automobile and PC industries were characterised by a great deal of turbulence in the first 20 to 30 years of their existence. In both cases, many new firms entered the industry, introduced new varieties of the product, and soon left the industry, leaving only a few dozen firms to compete during the growth phase. By 1926 only 33 per cent of the firms that had started producing automobiles during the previous 22 years had survived. In the case of PCs, by 1999 only 20 per cent of the fi
Both the automobile and PC industries were characterised by a great deal of turbulence in the first 20 to 30 years of their existence. In both cases, many new firms entered the industry, introduced new varieties of the product, and soon left the industry, leaving only a few dozen firms to compete during the growth phase. By 1926 only 33 per cent of the firms that had started producing automobiles during the previous 22 years had survived. In the case of PCs, by 1999 only 20 per cent of the fi
Reduce, Reuse, Recycle Campaign
If We Had No Moon - Part 3
The Moon's prominence in the sky and its regular cycle of phases have since ancient times made the Moon an important cultural influence on language, the calendar, art and mythology. The Moon's gravitational influence produces the ocean tides and the minute lengthening of the day. (10:19)