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4 | NewScientist | 21 May 2011 SHOULD a propensity to commit rape be considered a mental illness? Debate has been raging, and now it seems that “paraphilic coercive disorder” will not make its debut in the next edition of psychiatry’s diagnostic handbook. In February 2010, PCD was proposed for inclusion in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), scheduled for publication in 2013. An expert group convened by the American Psychiatric Association (APA) argued that PCD was distinct from sexual sadism, and applied to men who experienced intense fantasies or urges involving sexual coercion over a period of at least six months, if this caused them significant distress or impairment or had led them to force sex on “three or more non-consenting persons on separate occasions”. Medicalising rape Critics disputed evidence that PCD is a distinct mental disorder. It’s a “wastebasket category”, argues psychologist Raymond Knight at Brandeis University in Waltham, Massachusetts. The debate became highly charged, because many US states have laws that allow sex offenders who have served prison sentences to be detained indefinitely in a secure hospital if they are deemed dangerous “sexual predators”. A ruling from the US Supreme Court states that this can be done only if they have a mental disorder that makes them likely to commit further sexually violent acts. At present, many of those held under these laws have a vague diagnosis of “paraphilia (not otherwise specified)”, which is coming under legal challenge. The DSM-5 website now says PCD is being considered for inclusion in the manual’s appendix, rather than as a new diagnosis – a designation intended for conditions that need more research. The APA had not responded to requests for a rationale behind the change of plan as New Scientist went to press. Galaxy Idol results WHAT does the public want from a galaxy? As with rising pop stars, a complicated past can be an asset, according to an online survey that invited people to vote for their preferred definition. There is no formal definition of a galaxy. Most astronomers agree that it’s a massive bunch of stars bound by gravity. But what differentiates a galaxy from a large star cluster remains murky. Earlier this year, Duncan Forbes of Swinburne University of Technology in Hawthorn, Victoria, Australia, and Pavel Kroupa of the University of Bonn in Germany offered five possible criteria, including the presence of dark matter and multiple generations of stars. The pair then launched their voting website. Several months and 1638 votes later, 68 per cent say that a galaxy requires the “presence of complex stellar populations”. So a galaxy would boast an array of stars with different ages or chemical properties, while a cluster’s stars all formed around the same time. –Memphis inundated– A slow-motion disaster SMALL towns, farmland and wildlife refuges have been sacrificed in an attempt to save New Orleans and Baton Rouge from the massive flood of water that is rolling down the Mississippi river. Heavy rain and snowmelt are responsible for weeks of devastating floods in southern US. The water is predicted to take another couple weeks to reach the Gulf of Mexico. In a bid to avoid massive flooding in New Orleans and Baton Rouge, on 17 May the US Army Corps of Engineers decided for the first time since 1973 to open part of the Morganza Spillway, a huge flood- control structure in Louisiana. As New Scientist went to press, 11 of the 125 spillway gates had been opened, releasing the water to pour across the Atchafalaya basin, where up to 25,000 people are evacuating their homes. The hope is that this will reduce the burden on New Orleans’s levees. But David Rogers at the Missouri University of Science and Technology in Rolla warns: “If the river drops rapidly then comes back up again, that’s when all hell breaks loose – that’s when all the levees fail.” This was the outcome the last time the spillway was opened, in 1973. An overly fast drop in water levels causes a pressure change that weakens the soil in the levees, which may then fail if the water levels should quickly rise again. And when – like this year – heavy floods have already saturated the ground and filled up lakes, heavy rain could cause such rapid rises, says Rogers. “Many US states allow sex offenders to be detained indefinitely if they are deemed sexual predators” FOR the first time, the smell of human remains could be used as evidence in court. If the evidence is accepted, Arpad Vass from Oak Ridge National Laboratory in Tennessee will testify in the trial of Casey Anthony, who is accused of murdering her 2-year-old daughter. Vass will say that an air sample contains key chemicals given off by a decomposing body. Vass tested air taken from the trunk of Anthony’s car, and concluded Smell of death ‘in air from car’ MIKE BROWN/THE COMMERCIAL APPEAL/ZUMAPRESS.COM that it contained five of eight “signature” chemical compounds given off by a dead body. Prior to the case, Vass had collected air samples from human cadavers as they decomposed over four years, to build a database of the key chemicals they contain (Journal of Forensic Science, DOI: 10.1520/ JFS2003434). Comparing the air sample from the car to this database suggests it contained traces of human remains, Vass claims. UPFRONT
