One factor was product of aridification, others groups responded to favorable climatic periods and expanded across the available habitat, occur as opportunistic species across wide distribution other groups diverged in long time isolated areas.

An opportunistic disease requires impairment of host defenses, which may occur as a result of genetic defects ( such as Chronic granulomatous disease ), exposure to antimicrobial drugs or immunosuppressive chemicals ( as might occur following poisoning or cancer chemotherapy ), exposure to ionizing radiation, or as a result of an infectious disease with immunosuppressive activity ( such as with measles, malaria or HIV disease ).

In HIV-positive people, AIDS is officially diagnosed when the count drops below 200 cells / μL or when certain opportunistic infections occur.

The epidemic of AIDS, characterized by the occurrence of formerly rare opportunistic infections such as Pneumocystis carinii pneumonia ( PCP ) did not occur in the United States until a previously unknown human retrovirus — HIV — spread through certain communities.

Laurus genus responded to favourable climatic periods and expanded across the available habitat, occur as opportunistic species across wide distribution with close relatives and few species, indicating the recent divergence of this species.

COCOM models human performance as a set of control modes — strategic ( based on long-term planning ), tactical ( based on procedures ), opportunistic ( based on present context ), and scrambled ( random )-and proposes a model of how transitions between these control modes occur.

Nocardia asteroides is the species of Nocardia most frequently infecting humans, and most cases occur as an opportunistic infection in immunocompromised patients.

NetworkManager takes an opportunistic approach to network selection, attempting to use the best available connection as outages occur, or as the user roams between wireless networks.

The species does not occur in the intermediary miombo forests.

One seed-to-seed life cycle for an annual can occur in as little as a month in some species, though most last several months.

The ornithology of northern Africa presents a close resemblance to that of southern Europe, scarcely a species being found which does not also occur in the other countries bordering the Mediterranean.

Diynes and triynes, species with the linkage RC ≡ C-C ≡ CR ' and RC ≡ C-C ≡ C-C ≡ CR ' respectively, occur in certain plants ( Ichthyothere, Chrysanthemum, Cicuta, Oenanthe and other members of the Asteraceae and Apiaceae families ).

Most marine species live in tropical waters, but a few occur in oceanic trenches, and others are found in polar waters.

They can explain why chemistry is so prevalent in the interstellar medium, where many different polyatomic species have been detected ( by radio astronomy ), but where temperatures are so low that conventional wisdom might suggest that chemical reactions do not occur.

Other early ethologists, such as Oskar Heinroth and Julian Huxley, instead concentrated on behaviours that can be called instinctive, or natural, in that they occur in all members of a species under specified circumstances.

Oxidation and reduction always occur in a paired fashion such that one species is oxidized when another is reduced.

The habitat of a species describes the environment over which a species is known to occur and the type of community that is formed as a result.

Von Baer ’ s embryo drawings display that individual development proceeds from general features of the developing embryo in early stages through differentiation into special features specific to the species, establishing that linear evolution could not occur.

In the Southern Hemisphere, most coniferous trees ( members of the Araucariaceae and Podocarpaceae ) occur in mixtures with broadleaf species that are classed as broadleaf and mixed forests.

# Native species plantation – Intensively managed forests with > 30 % canopy cover, which have been planted by people with species that occur naturally in that country.

# Native species plantation – Intensively managed forests with > 30 % canopy cover, which have been planted by people with species that occur naturally in that country.

In most cases the aim is to introduce a new trait to the plant which does not occur naturally in this species.

This single ovulation event is believed to coincide with the species ’ annual migration patterns, when births can occur in warmer waters.

The latter cation is written as though composed of a bare proton, but in reality, hydrogen cations in ionic compounds always occur as more complex species.

Concealed ovulation and menopause in women both also occur in a few other primates however, but are uncommon in other species.

Both species have much grey in their wings in males, which does not occur in the Common Kestrel or its close living relatives but does in almost all other falcons.

Mutagenesis may occur endogenously, for example through spontaneous hydrolysis, or through normal cellular processes that can generate reactive oxygen species and DNA adducts, or through error in replication and repair.

Close to 70 % of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central America, and one in North America, north of Mexico.

However, some species exhibit sex-role reversed behavior in which it is males that are most selective in mate choice ; the best-known examples of this pattern occur in some fishes of the family Syngnathidae, though likely examples have also been found in amphibian and bird species.

Communication requires a sender, a message, and a recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication ; thus communication can occur across vast distances in time and space.

In light of the physical interpretation, a vector field with constant zero divergence is called incompressible or solenoidal – in this case, no net flow can occur across any closed surface.

The facilitated diffusion may occur either across biological membranes or through aqueous compartments of an organism.

This was supposed to occur across a migrating front.

Communications in Jordan occur across many media, including telephone, radio, television, and internet.

Generally, monsoons occur at the same time across the country, although that time may vary significantly from one year to the next.

Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication ; thus communication can occur across vast distances in time and space.

The 19th century saw breakthroughs occur after observing networks developed across several countries.

Similar actions, with similar results, occur when the vocal cords are contracted or relaxed across the larynx.

RVF outbreaks occur across sub-Saharan Africa, with outbreaks occurring elsewhere infrequently, but sometimes severely.

This is because if the pressure rises high enough, a compressor stall will occur, where the stored pressurized air decompresses backward across the impeller and out the inlet.

This experience can occur in different ways ; it can be one transforming moment, such as an altar call experience, or it may involve a series of decisions across a period of time.

Why emergent behaviours occur include: intricate causal relations across different scales and feedback, known as interconnectivity.

Tornadoes also occur across northeastern Mexico.

They occur all across the world except for Antarctica, Australia, and neighbouring islands.

They occur across East Asia, from 50 ° N latitude in Sakhalin through to Northern Australia, and west to India and the Himalayas.

* Floods can occur if water accumulates across an impermeable surface ( e. g. from rainfall ) and cannot rapidly dissipate ( i. e. gentle orientation or low evaporation ).

If the flash controller does not track the total number of reads across the whole storage device and rewrite the surrounding data periodically as a precaution, a read disturb error will likely occur, with data loss as a result.

Giant dust storms that sweep across the world's deserts contribute 8 % of the mineral dust in the atmosphere each year during the handful of storms that occur.

Like in triboluminescence, if the charge separation results in a large enough electric potential, a discharge across the gap and through the bath gas between the interfaces can occur.

Juneteenth Flag raisings occur in cities across America, including Boston, MA, Dallas, TX, Omaha, NE and Fort Smith, AR.

The most frequently suggested of these reasons is to avoid blurring of the image, which would occur if the response time of a photoreceptor is longer than the time a given portion of the image is stimulating that photoreceptor as the image drifts across the eye.

Although there is a general movement of material from uplands to lowlands, erosion, transport, and deposition often occur in closely spaced tandem all across the landscape.