Particle (ecology)

In marine and freshwater ecology, a particle is a small object. Particles can remain in suspension in the ocean or freshwater. However, they eventually settle (rate determined by Stokes' law) and accumulate as sediment. Some can enter the atmosphere through wave action where they can act as cloud condensation nuclei (CCN). Many organisms filter particles out of the water with unique filtration mechanisms (filter feeders). Particles are often associated with high loads of toxins which attach to the surface. As these toxins are passed up the food chain they accumulate in fatty tissue and become increasingly concentrated in predators (see bioaccumulation). Very little is known about the dynamics of particles, especially when they are re-suspended by dredging. They can remain floating in the water and drift over long distances. The decomposition of some particles by bacteria consumes a lot of oxygen and can cause the water to become hypoxic.

Particle analysis

Particle levels in water (or air) can be measured with a turbidity meter and analyzed with a particle counter. They can also be scanned with an underwater microscope, such as ecoSCOPE. Collected particles of size 20 - 200 micrometers hovering in the free water in the vicinity of a harbor had the following contaminant levels (table). Many of those contaminants are carcinogenic.

Particle

A particle is a minute fragment or quantity of matter. In the physical sciences, the word is used to describe a small localized object to which can be ascribed several physical or chemical properties such as volume or mass; subatomic particles such as protons or neutrons; and other elementary particles. The word is rather general in meaning, and is refined as needed by various scientific fields. Something that is composed of particles may be referred to as being particulate. However, the term particulate is most frequently used to refer to pollutants in the Earth's atmosphere, which are a suspension of unconnected particles, rather than a connected particle aggregation.

Conceptual properties

The concept of particles is particularly useful when modelling nature, as the full treatment of many phenomena is complex. It can be used to make simplifying assumptions concerning the processes involved. Francis Sears and Mark Zemansky, in University Physics, give the example of calculating the landing location and speed of a baseball thrown in the air. They gradually strip the baseball of most of its properties, by first idealizing it as a rigid smooth sphere, then by neglecting rotation, buoyancy and friction, ultimately reducing the problem to the ballistics of a classical point particle. The treatment of large numbers of particles is the realm of statistical physics.

Ecology

Ecology (from Greek: οἶκος, "house", or "environment"; -λογία, "study of") is the scientific analysis and study of interactions among organisms and their environment. It is an interdisciplinary field that includes biology, geography and Earth science. Ecology includes the study of interactions organisms have with each other, other organisms, and with abiotic components of their environment. Topics of interest to ecologists include the diversity, distribution, amount (biomass), and number (population) of particular organisms, as well as cooperation and competition between organisms, both within and among ecosystems. Ecosystems are composed of dynamically interacting parts including organisms, the communities they make up, and the non-living components of their environment. Ecosystem processes, such as primary production, pedogenesis, nutrient cycling, and various niche construction activities, regulate the flux of energy and matter through an environment. These processes are sustained by organisms with specific life history traits, and the variety of organisms is called biodiversity. Biodiversity, which refers to the varieties of species, genes, and ecosystems, enhances certain ecosystem services.

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photo: WN

A man holding Islamic State Militant's flag

'British' boy in Islamic State group execution video

Edit BBC News 27 Aug 2016

The Islamic State group has released footage showing five boys, including one it identifies as British, carrying out the killing of prisoners in Syria ... The video shows the children shooting dead five men identified as captured Kurdish fighters who are kneeling ... ....

photo: Creative Commons / Gage Skidmore

Donald Trump speaking with supporters at a campaign rally at Veterans Memorial Coliseum at the Arizona State Fairgrounds in Phoenix, Arizona, 18 June 2016

Trump: African-Americans will vote for me after Dwyane Wade's cousin killed in shooting

Edit Politico 27 Aug 2016

Donald Trump on Saturday tweeted that the fatal shooting of professional basketball star Dwyane Wade's cousin in Chicago is a reason why African-Americans will support his candidacy. "Dwayne Wade's cousin was just shot and killed walking her baby in Chicago ... — Donald J ... ....

photo: US Navy / Navy Petty Officer 2nd Class Dominique A. Pineiro

File - U.S. Marine Corps Gen. Joseph F. Dunford Jr., chairman of the Joint Chiefs of Staff, receives a briefing from U.S. Army Col. James Minnich during a visit to the Demilitarized Zone dividing the two Koreas, Nov. 2, 2015.

North Korea threatens to fire on Demilitarised Zone after 'provocation' by South Korean and US troops

Edit The Independent 27 Aug 2016

North Korea has threatened to aim fire at the lighting equipment used by “provocative” American and South Korean troops at a truce village inside the Demilitarized Zone that divides the two Koreas, Korean People's Army (KPA) announced on Saturday ... and South Korea that Pyongyang says are an invasion rehearsal ... 19 show all ....

photo: AP / Robert F. Bukaty

In a Friday, Jan. 8, 2016 file photo, Gov. Paul LePage speaks at a news conference at the State House, in Augusta, Maine, where he apologized for his remark about out-of-state drug dealers impregnating "young white" girls.

Maine Governor Paul LePage criticised for 'racist' remarks

Edit BBC News 27 Aug 2016

The governor of Maine has said that people of colour were enemies of his state, and appeared to suggest they should be shot. Speaking about Maine's effort to combat drug crime, Paul LePage said that "the enemy right now... are people of colour or people of Hispanic origin". "When you go to war... and the enemy dresses in red and you dress in blue, then you shoot at red," he said. Leading Democrats have urged him to resign ... He said ... ....

photo: WN / Aruna Gilbert

AG2 Dwyane Wade in attendance at the Women's Finals of the Sony Ericsson Open in Key Biscayne, Florida on April 5, 2008

Dwyane Wade's cousin fatally shot pushing baby in stroller

Edit Times Free Press 27 Aug 2016

CHICAGO (AP) - NBA star Dwyane Wade's cousin was shot and killed in Chicago while pushing her baby in a stroller near a school where she intended to register her children. Wade took to Twitter to lament what he called another "act of senseless gun violence.". Her family said Nykea Aldridge, 32, had recently relocated to the area on the city's South Side ... She wasn't the intended target, police said ... "My cousin was killed today in Chicago....

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'Dark twin' of the Milky Way galaxy discovered

Edit CNN 27 Aug 2016

(CNN)Welcome to the dark side of the universe ... Although it's massive and mysterious, Dragonfly 44 is really just misunderstood ... Read More ... "We could be looking for the dark matter particle itself. Currently, people are looking at tiny dwarf galaxies that circle the Milky Way to search for the dark matter particle with X-ray and UV telescopes, but nothing has been found yet ... We don't even know if it is a particle or not ... ....

West Palm Beach police seeing an increase in fentanyl-related drug overdoses

Edit WPTV 27 Aug 2016

WEST PALM BEACH, Fla-- It’s been a sobering 7 months for Richard White. “I’ve been a wreck. I just recently stopped crying every day,” said White. In February, the love of his life, Nicole Smith White, died from a drug overdose. The couple had moved to West Palm Beach to get sober. “For two addicts, it was nearly impossible,” he said ... The equipment sucks up any fumes or particles to avoid any future contamination ... ....

Being stuck in traffic jams may increase cancer risk: study

Edit Deccan Chronicle 27 Aug 2016

London. Apart from wasting your time, long traffic jams may cause exposure to toxic fumes, and potentially increase various health risks, including cancer, say researchers, one of them of Indian origin ... Previous studies have shown that drivers stuck at traffic lights were exposed up to 29 times more harmful pollution particles than those driving in free flowing traffic. The new research, published in the journal Environmental Science ... ....

Astronomers discover 'dark' Milky Way

Edit DNA India 27 Aug 2016

--> Sat, 27 Aug 2016-03.30pm , Washington , PTI. Astronomers discover a galaxy the size of the Milky Way made almost entirely of dark matter ... It is a diffuse "blob" about the size of the Milky Way, but with far fewer stars, researchers said ... The race is on to find massive dark galaxies that are even closer to us than Dragonfly 44, so we can look for feeble signals that may reveal a dark matter particle," said Van Dokkum ... ....

Masks fly off shop shelves as smoke shrouds Singapore

Edit The Jakarta Post 27 Aug 2016

Grey skies and a familiar burning smell greeted Singaporeans on Friday morning as the haze made a return. On the streets, people young and old were seen wearing face masks, while others held cloth over their mouths and noses. The sudden spike in demand for N95 masks on Friday caught retailers by surprise, with some shops running out of stock in the middle of the day. N95 masks can filter out fine particles found in the haze ... ....

Review: When Particles Collide, `Ecotone'

Edit Boston Herald 26 Aug 2016

“Fight,” the lead cut from When Particles Collide’s album “Ecotone,” manages to combine strange bits into a smart, simple jam right for radio. The New Hampshire-via-Maine duo When Particles Collide have filled out 2015 EP ......