domenica 16 giugno 2013

L'importanza della stupidità nella ricerca scientifica parte II

Continuando la raccolta degli articoli a prima svista inutili e scellerati (se non erro questa è la quarta puntata) non dobbiamo dimenticare di dare un posticino ai capolavori dedicati alle scienze sociali, come per esempio: "The Effect of Country Music on Suicide" - Social Forces
Vol. 71, No. 1 (Sep., 1992), pp. 211-218 - .
www.oddee.com
Secondo gli autori, Steven Stack and Jim Gundlach, il papero "assesses the link between country music and metropolitan suicide rates. Country music is hypothesized to nurture a suicidal mood through its concerns with problems common in the suicidal population, such as marital discord, alcohol abuse, and alienation from work. The results of a multiple regression analysis of 49 metropolitan areas show that the greater the airtime devoted to country music, the greater the white suicide rate. The effect is independent of divorce, southernness, poverty, and gun availability. The existence of a country music subculture is thought to reinforce the link between country music and suicide. Our model explains 51% of the variance in urban white suicide rates." 

E che dire di questa perla interdisciplinare proveniente dall'Università di Stoccolma? Il titolo la dice tutta: "Chickens prefer beautiful humans" (trad. appr. "i galli preferiscono le belle donne") - Human Nature September 2002, Volume 13, Issue 3, pp 383-389; premio Ig-Nobel 2003 -.
Stefano Ghirlanda, Liselotte Jansson e Magnus Enquist, "trained chickens to react to an average human female face but not to an average male face (or vice versa). In a subsequent test, the animals showed preferences for faces consistent with human sexual preferences (obtained from university students). This suggests that human preferences arise from general properties of nervous systems, rather than from face-specific adaptations. We discuss this result in the light of current debate on the meaning of sexual signals and suggest further tests of existing hypotheses about the origin of sexual preferences". A proposito di Stefano Ghirlanda vi dirò che possiede un blog, drghirlanda, dedicato alle neuroscienze, all'evoluzione e alla cultura e che, tra le altre cose, è stato coautore di un articolo molto interessante: "Shared Culture Needs Large Social Networks". 

Dall'abstract: "We report on a model for the emergence of shared cultural traits in a large group of individuals that imitate each other and interact in random social networks. The average size of the social network is shown to be a crucial variable ruling the emergence of a prevalent cultural trait shared by a majority of individuals. We distinguish between the case of a social network that changes while individuals develop their culture through the influence of others and the case of social networks which change slowly so that individuals reach a stable trait value before their social network changes appreciably. In both cases, no shared cultural trait emerges unless social network size is larger than a critical value. We also discuss how the formation of a shared cultural trait depends on the strength of mutual imitation, random factors that affect individuals’ decisions, and external influences such as social institutions." In quest'ottica, presto o tardi, perfino i blogger e i divulgatori di scienza finiranno per scrivere e dire sempre le stesse cose, nella condivisione di un'unica forma mentis (e i primi esempi a quanto pare non mancano).

Ma cambiamo tematica. I seguenti articoli riguardano un argomento delicatissimo, tristemente noto a tutti quei genitori che sono soliti vestire in fretta e furia i loro figli prima di portarli all'asilo e, in modo particolare, agli imbranati patologici che godono di un tormentato rapporto con le zip...e non solo:

Management of penile zipper injury - J Urol. 1977 May;117(5):671.
A novel method for removal of penile zipper entrapment Pediatr Emerg Care. 1999 Dec;15(6):412-3 - "Penile entrapment in a zipper is a presentation that may be seen in any emergency department. A method of release is presented that has not been previously described in the literature."
Extrication of penile entrapment in a polyethylene terephthalate (PET) bottle: a technique of suture traction and Dundee and literature review Int Urol Nephrol. 2012 Oct;44(5):1335-40 - "The PET bottle neck was removed intact successfully in 50 min. Follow-up revealed he got full recovery without any complications. Literature review shows that penile incarceration in PET bottle is frequently described as an isolated case report or small series, the approach for dealing with these problems are often described using cutting instruments, the PET bottle could produce a fatal harm in extreme situation."
- ecc. ecc. ecc.

La letteratura medica è piena di articoli e review dedicati a questo pernicioso problema... mi viene da pensare che siamo ben lontani da una soluzione definitiva.

Ma passiamo alle neuroscienze: "Navigation-related structural change in the hippocampi of taxi drivers" - PNAS April 11, 2000 vol. 97 no. 8 - è il titolo, e questo è quanto affermano i ricercatori del Dip. di Neurologia Cognitiva dell'Università di Londra: "Structural MRIs of the brains of humans with extensive navigation experience, licensed London taxi drivers, were analyzed and compared with those of control subjects who did not drive taxis. The posterior hippocampi of taxi drivers were significantly larger relative to those of control subjects. A more anterior hippocampal region was larger in control subjects than in taxi drivers. Hippocampal volume correlated with the amount of time spent as a taxi driver (positively in the posterior and negatively in the anterior hippocampus). These data are in accordance with the idea that the posterior hippocampus stores a spatial representation of the environment and can expand regionally to accommodate elaboration of this representation in people with a high dependence on navigational skills. It seems that there is a capacity for local plastic change in the structure of the healthy adult human brain in response to environmental demands. ...". 

Nel 2006, Antonio Mulet e colleghi dell'Università di Valencia hanno ottenuto il prestigioso Ig-Nobel per la chimica grazie allo studio:   "Ultrasonic Velocity in Cheddar Cheese as Affected by Temperature" - Journal of Food Science Volume 64Issue 6pages 1038–1041, November 1999 -. "The ultrasonic velocity in Cheddar cheese is temperature dependent. This relationship can be used to make corrections when determining ultrasonic texture or to determine mean temperatures in cooling/heating processes. At 0 < T < 35 °C ultrasonic velocity was 1590 to 1696 m/s, at 0 and 35 °C, respectively. Differential Scanning Calorimetry thermograms linked the temperature dependence of ultrasonic velocity to fat melting. Three parts are distinguished in the curve as a consequence of the fat melting and the appearance of free oil. The most reliable temperature interval to carry out ultrasonic measurements in Cheddar cheese is identified as 0 to 17 °C."

Ma al formaggio sono stati dedicati diversi articoli scientifici già a partire dai primi vent'anni del secolo scorso. La formazione dei buchi nel formaggio svizzero è costata più di un secolo di approfondite indagini, iniziate dal biochimico William Mansfield Clark, con il suo "On the formation of "eyes" in Emmental cheese" nel 1917.
L'autore ci spiega come "The quality of a prime Emmental cheese is determined not alone by its sweet, nutty flavor and pliant texture, but also by the character of its holes. Cracks, which frequently mar the appearance of a cheese, are intimately connected with a faulty texture." La qualità dei buchi nel formaggio ha un'importanza enorme ed è per questa ragione che i cheese-bubble researchers sparsi in ogni parte del mondo hanno utilizzato Scanning Electron Microscopes, Computerised Image Analysis, X-rays, Ultrasound e Nuclear Magnetic Resonance techniques per quantificare, misurare, monitorare la formazione dei buchi e capire come si formano. Il compendio "Technology of Cheesemaking" (2010) dedica un intero capitolo al problema, sottolineando però come a tutt'oggi rimangano diversi seri interrogativi: “A nucleus is necessary for the eye formation (Clark, 1917). It could be an air bubble attached to a solid curd particle, but the nucleation is not yet clearly understood.”(vedi: Improbable Research). Per approfondire potrei consigliarvi anche questo libro: Cheese: Chemistry, Physics and Microbiology, giusto per comprendere quanto questa tematica sia di carattere multidisciplinare.

E per oggi direi che basta così. Prossimamente si approfondirà la scienza dei buchi (non solo quelli del formaggio), le rimarchevoli proprietà della birra e molte altre cosette che ho già raccolto e messo da parte. S.T.

Bibliografia
http://www.oddee.com/item_90683.aspx
http://www.improbable.com/2011/12/07/fillable-entities/


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