A dirlo è Matthew During e il suo gruppo di ricerca presso l’Ohio State University Medical Center, negli Usa, che da tempo indagano sugli effetti della socialità sulla salute. Secondo il loro ultimo studio, pubblicato su Cell Metabolism, un ambiente ricco di stimoli innescherebbe un meccanismo importante per bruciare in maniera efficace le calorie in eccesso: la trasformazione del grasso bianco (che immagazzina i lipidi) in grasso bruno (tipico dei neonati, che brucia i grassi per produrre calore). Finora solo l’esposizione a lunghi periodi di freddo sembrava in grado di attuare lo stesso processo fisiologico.
La ricerca è stata condotta su alcuni topi a cui gli scienziati hanno rivoluzionato l’ambiente: gruppi di 15 o 20 individui sono stati posti in gabbie molto spaziose, attrezzate con ruote girevoli, percorsi con tunnel e labirinti, giochi in legno e materiale per costruire i nidi, oltre che con riserve illimitate di cibo e acqua. Per poter verificare e confrontare gli effetti dell’ambiente sulla salute dei topi, i ricercatori hanno mantenuto dei gruppi di controllo, ognuno costituito da 5 individui posti nelle normali condizioni di laboratorio (piccole gabbie con cibo e acqua a volontà, ma senza giochi).
Dopo quattro settimane, During ha notato che, a parità di cibo ingerito, i topi del primo gruppo non solo avevano preso meno peso rispetto agli animali di controllo – come era logico aspettarsi – ma soprattutto avevano perduto quasi il 50 per cento del tessuto adiposo bianco addominale. Riduzione che non sembrava essere dovuta esclusivamente all’aumento di attività. Questi topi, infatti, presentavano una temperatura corporea più elevata, segnale di una maggiore quantità di energia prodotta e quindi di grasso bruno in aumento: un fattore che evita l’insorgere dell’obesità per eccessiva alimentazione.
Secondo During, l’interruttore biologico in grado di attuare questa conversione del grasso risiederebbe in un circuito neuronale che coinvolge l’ipotalamo. Un ambiente stimolante aumenta infatti la produzione di una proteina chiamata BDNF (brain-derived neurotrophic factor), implicata nel controllo dell’ingestione di cibo e nel bilancio energetico, in questa area cerebrale. L’aumento dei livelli di BDNF fa poi partire alcuni segnali del sistema simpatico diretti alle cellule del grasso bianco. Tali segnali, a loro volta, attivano specifici geni per la produzione di grasso bruno, Prdm16 e Ucp1 (vedi Galileo: “Gli interruttori del grasso buono”).
TheNew York Timesreported Thursday thatTristane Banon, the French journalistwho has accused disgraced ex-IMF chief Dominique Strauss-Kahn of attempting to rape her back in 2003, was questioned jointly with DSK at a Paris police station for over two hours. This, of course, is on the heels of the high-profile rape allegations againstDSK made by a hotel maid in the U.S. According to theTimes, "The joint questioning, a normal part of sexual assault cases in France, could represent a last legal step for prosecutors before either bringing formal charges, or dropping the case." How does this joint questioning work?
Cécile Dehesdin, a reporter atSlate's French sister site,Slate.fr, says that this joint questioning isn't mandatory. If the accused rapist denies the charges, according to a French organization for women devoted to helping rape victims, the alleged victim can accept the joint questioning, refuse it outright, or ask that the face-to-face happen, not with the police, but with the judge who will eventually be in charge of investigating the case. In France, unlike in the U.S., the judge (juge d'instruction) is in charge of investigating for both the alleged victim and the accused. DSK has called Banon's accusations of rape "imaginary and slanderous" in a recent interview. For her part, Banon has always said sherelished the idea of facing DSK in person:
The police asked me if i'd agree to a face to face, of course I said yes. I'd like him to be facing me and telling me to my face that those are imaginary facts. I'd like to see him try and say that.
In this joint questioing, Dehesdin points out, the victim and alleged attacker are in the same room, but they don't address each other directly. They just answer the police or judge's questions. Whoever has conducted the questioning gives the information to the district attorney, who then decides if there is enough evidence to move forward with the case (updated to add: if the juge d'instruction has done the questioning, he doesn't need permission from the DA to pursue the case).
Even if the D.A. decides not to pursue the case, Banon has some recourse. Since she was questioned by police, she could refile the criminal complaint along with a civil complaint, and at that point the juge d'instruction would have to investigate. According topress reports in France, DSK did admit that he made a pass at her.
When fully developed as a hand-held, portable sensor, like something you might see in a science fiction movie, it will provide a whole diagnostic laboratory on a single chip.
The research could revolutionize the size, speed and accuracy of chemical detection systems around the world.
New findings on this "microfluidic sensor" were recently reported inSensors and Actuators B: Chemical, a professional journal, and the university is pursuing a patent on related technologies. The collaborative studies were led by Vincent Remcho, an OSU professor of chemistry, and Pallavi Dhagat, an assistant professor in the OSU School of Electrical Engineering and Computer Science.
The key, scientists say, is tapping into the capability of ferromagnetic iron oxide nanoparticles -extraordinarily tiny pieces of rust. The use of such particles in the new system can not only detect chemicals with sensitivity and selectivity, but they can be incorporated into a system of integrated circuits to instantly display the findings.
This diagram illustrates how a new sensor technology developed at Oregon State University might work using magnetic beads. (Credit: Graphic courtesy of Oregon State University)
"The particles we're using are 1,000 times smaller than those now being used in common diagnostic tests, allowing a device to be portable and used in the field," said Remcho, who is also associate dean for research and graduate programs in the OSU College of Science.
"Just as important, however, is that these nanoparticles are made of iron," he said. "Because of that, we can use magnetism and electronics to make them also function as a signaling device, to give us immediate access to the information available."
According to Dhagat, this should result in a powerful sensing technology that is fast, accurate, inexpensive, mass-producible, and small enough to hold in your hand.
"This could completely change the world of chemical assays," Dhagat said.
Existing assays are often cumbersome and time consuming, using biochemical probes that require expensive equipment, expert personnel or a complex laboratory to detect or interpret.
In the new approach, tiny nanoparticles could be attached to these biochemical probes, tagging along to see what they find. When a chemical of interest is detected, a "ferromagnetic resonance" is used to relay the information electronically to a tiny computer and the information immediately displayed to the user. No special thin films or complex processing is required, but the detection capability is still extremely sensitive and accurate.
Essentially, the system might be used to detect almost anything of interest in air or water. And the use of what is ordinary, rusty iron should help address issues of safety in the resulting nanotechnology product.
Rapid detection of chemical toxins used in bioterrorism would be possible, including such concerns as anthrax, ricin or smallpox, where immediate, accurate and highly sensitive tests would be needed. Partly for that reason, the work has been supported by a four-year grant from the Army Research Laboratory, in collaboration with the Oregon Nanoscience and Microtechnologies Institute.
However, routine and improved monitoring of commercial water treatment and supplies could be pursued, along with other needs in environmental monitoring, cargo inspections, biomedical applications in research or medical care, pharmaceutical drug testing, or even more common uses in food safety.
Other OSU researchers working on this project include Tim Marr, a graduate student in electrical engineering, and Esha Chatterjee, a graduate chemistry student.
The concept has been proven in the latest study, scientists say, and work is continuing with microfluidics research to make the technology robust and durable for extended use in the field.
Cel mai cunoscut pictor norvegian, Edvard Munch (1863-1944), a fost un monument de anxietate, un simbol al suferintelor psihice transpuse într-o opera care graviteaza în jurul unei lucrari excesiv mediatizate. Biografia acestui artist, care admitea înca din tinerete ca a mostenit „semintele nebuniei” de la tatal sau, este tipica unui om bolnav care încearca sa-si gaseasca o identitate artistica si o liniste interioara care sa-l departeze de ganduri suicidale. Considerat un simbolist si un premergator al expresionismului, Edvard Munch este mereu în actualitate datorita lucrarii intitulate „Strigatul”, care continua sa intrige si sa farmece prin disperarea mesajului sau.
Pare incredibil, dar Strigatul lui Munch a starnit mai multe controverse decat opera de o viata a unor pictori contemporani. Uluitoare este si comparatia cu Mona Lisa a lui Leonardo da Vinci – din punct de vedere al notorietatii. Atat de obsedat a fost Munch de importanta mesajului transmis de chipul distorsionat care îsi striga disperarea, în timp ce soarele apune, încat a creat mai multe versiuni, toate la fel de pretioase.
Cele patru variante, în ulei pe panza si tempera, sunt detinute de Munch Museum, Galeria Nationala Norvegiana si de catre un colectionar particular norvegian. Prima realizare dateaza din 1893 si a fost intitulata „Strigatul naturii”. Acest titlu avea sa fie premonitoriu pentru ceea ce a urmat în legatura cu ecourile mereu inflamate ale operei. Nu vreau sa fiu malitios – nefiind decat un consumator de arta –, dar lucrarea este departe de a fi o capodopera a frumosului.
A epatat însa prin hidosenia personajului din prim-plan si prin sinceritatea dezarmanta a gestului: urletul acelei fiinte este autentic si parca îl si auzim. Este reactia unui om care este martorul unui cataclism si care, cu acea ocazie, îsi descopera vulnerabilitatea si iminenta mortii. În urma faimei dobandite, Munch a considerat necesar sa se explice. Pe scurt, pictorul spunea ca, aflat pe un pod, a vazut cum soarele apunand devine rosu si trimite „limbi de foc amenintatoare” pe cer. Instantaneu, lui i s-a parut ca sunt „fasii de sange ale naturii”, care-si striga astfel disperarea. Asa se face ca ceea ce era în sufletul unui om chinuit de angoasa se raspandea în mediul considerat ostil existentei sale.
De la aceasta metafora s-a ajuns la niste interpretari fabuloase, care merita mentionate, chiar daca eu personal cred ca sunt comentarii menite sa umfle notorietatea lucrarii. Astfel, am gasit comparatii cu exceptionala eruptie vulcanica din Krakatoa, petrecuta cu zece ani înainte. Norii de cenusa rezultati au colindat prin atmosfera terestra aproape un an si i-ar fi vazut si Munch. Fiinta schimonosita de groaza ar fi rezultatul inspiratiei pictorului din imaginea mumiilor peruviene pe care Munch le-a vazut la Expozitia Universala de la Paris, din 1889 (socanta fizionomie apare si în unele lucrari ale lui Paul Gauguin, un amic al norvegianului). Mai nou, unii critici spun ca o alta mumie a fost sursa, si anume una din Muzeul de istorie naturala din Florenta... Pardon de expresie, cam asa cresc preturile unor lucrari importante. Numai ca în posteritatea autorului maniaco-depresiv s-au petrecut si alte fapte care au atras atentia asupra Strigatului.
Doua variante ale sale au fost furate si s-a facut, evident, mare tam-tam în jurul disparitiilor. Mai mult, primul furt s-a petrecut chiar în ziua deschiderii Jocurilor Olimpice de iarna de la Lillehammer (Norvegia), la 12 februarie 1994! Sportivii au fost uitati, dar recuperarea tabloului a întarziat cu doi ani. În 2004, Strigatul a fost din nou furat si recuperat dupa un an. Prima oara, hotii au lasat la muzeu un biletel pe care scria: „Multumim pentru proasta securitate”.
Ricreare in laboratorio il tessuto nervoso danneggiato dal morbo di Parkinson: un obiettivo che potrebbe essere possibile a partire dalle cellule somatiche. Gli scienziati dell'Istituto Scientifico Universitario San Raffaele hanno infatti identificato tre geni che se attivati trasformano i fibroblasti, le cellule che forniscono fibre e collagene ai tessuti e ne garantiscono la struttura, in neuroni dopaminergici indotti (iDA). Questi ultimi hanno funzionalità del tutto simili a quelle delle cellule cerebrali che si trovano nella zona dell'encefalo colpita dalla malattia, chiamate per l'appunto neuroni dopaminergici. Lo studio è stato pubblicato su Nature. Era già noto ai ricercatori che il trapianto di neuroni potesse essere parte del trattamento della malattia neurodegenerativa, ma finora l'unica sorgente utilizzabile a scopo clinico per la produzione di tessuto cerebrale era quella delle cellule staminali embrionali. Oltre a sollevare questioni etiche, in questo caso l'uso di cellule pluripotenti - se non controllato correttamente - potrebbe anche portare, secondo gli scienziati, all’insorgenza di tumori.
Per questo il gruppo di ricerca milanese ha sviluppato una nuova tecnica che si basa sulla conversione diretta di cellule del tessuto connettivo provenienti da donatori sani o dagli stessi malati di Parkinson. Tramite l'attivazione di tre geni (Mash1, Nurr1, Lmx1a) vengono codificate tre proteine che inducono i fibroblasti a differenziarsi in neuroni iDA direttamente funzionali: le cellule così ottenute presentano un'attività elettrica spontanea e rilasciano dopamina, il neurotrasmettitore la cui riduzione è responsabile dei disturbi di chi soffre della malattia.
Serviranno ulteriori ricerche per capire se questo nuovo metodo possa essere applicato nel trattamento della malattia: “I neuroni iDA presentano importanti vantaggi, come quello di poter essere generati dal paziente stesso in maniera riproducibile, in un tempo relativamente breve e senza nessun rischio di tumori - ha detto Vania Broccoli, direttore dell'Unità di Cellule Staminali e Neurogenesi del San Raffaele e coordinatore dello studio - comunque solo i prossimi studi, in via di progettazione direttamente in modelli animali della malattia di Parkinson, accerteranno se i neuroni iDA possano diventare una fonte adatta per questo tipo di utilizzo in clinica”.
Gli scienziati sono convinti che la generazione diretta di neuroni dopaminergici a partire da cellule somatiche potrebbe avere implicazioni importanti non solo nel trattamento del morbo, ma anche nella comprensione dei processi di sviluppo cerebrale, nella modellizzazione in vitro delle patologie neurodegenerative e nella creazione di terapie sostitutive per malattie simili al Parkinson.
A continuous and repetitive thread in the commentary on the decade since 9/11 — one might almost call it an endless and open-ended theme — was the plaintive observation that the struggle against al-Qaeda and its surrogates is somehow a “war without end.” (This is variously rendered as “perpetual war” or “endless war,” just as anti-war articles about the commitment to Iraq used to relentlessly stress the idea that there was “no end in sight.”)
I find it rather hard to see the force of this objection, or indeed this description. Was there ever a time when we involved ourselves in combat, or found ourselves involved, with any certain advance knowledge about the timeline and duration of hostilities? Are there two kinds of war, one of them term-limited? A bit like that other tempting but misleading separation of categories — between “wars of choice” and “wars of necessity” — this proves upon closer scrutiny to be a distinction without much difference.
In order even to aspire to such a nebulous timeline, there would first have to be consensus on when the war actually started. For example, I would say that hostilities between the United States and Saddam Hussein began in the early 1990s, if only at a relatively low level, after he had violated all the conditions of the cease-fire that had allowed him to retain power in 1991, and after he had begun regularly firing upon the planes that patrolled and enforced the cease-fire and the “no-fly” zones. For more than a decade, the only response to this was more air patrols and a reliance on a crumbling regime of sanctions. That really was a case of “no end in sight.” But something tells me that this is not the sort of example that my opponents have in mind.
Then again, one might ask how long we have been at war with al-Qaeda or its equivalents. Since the attack on the World Trade Center in 1993? Since the destruction of the U.S. embassies in Africa? Since the near-sinking of the USS Cole in Aden harbor in 2000? Even to invite these questions is to arouse the unnerving suspicion that there was quite a long period during which al-Qaeda was at war with us, but we did not understand that we were at war with it. It was precisely that queasy feeling that was beginning to creep over some of us a while before the events of a decade ago dispelled most doubts. And it would have been just as true to say “no end in sight” on Sept. 12, 2001, as it would be to say it today — more true, if anything. So once again, those who want to set the clock must be crystal clear about when they think the confrontation started running.
Attitudes toward length are often a good clue to attitudes toward outcome. During the Bosnian conflict, those of us who favoured using force to lift the siege of Sarajevo were accused of advocating a tactic that would “lengthen” the war. Even in the trivial sense of being true by definition (anything that denied Gen. Ratko Mladic a cheap, easy and swift victory over civilians was necessarily war-prolonging to some extent), this wasn’t true in any serious way. The relatively brief bombardment of Serbian artillery positions had the effect of exposing the hollowness of Mladic’s military strength: Within an amazingly short time, Slobodan Milosevic himself was at Dayton asking for terms. One might phrase it like this: Intervention slightly lengthened hostilities in the short term, but drastically shortened them in the long term. (Milosevic later misinterpreted the Dayton agreements as lenience and tried to repeat his Bosnian tactics in Kosovo. But even if this could be construed as war-prolonging, it also led to the eventual defeat of his army and overthrow of his regime, and thus to a conclusive finish.)
John Moore/Getty Images
A U.S. Marine runs to avoid sniper fire during an operation in Ramadi on Jan. 17, 2007, in the Anbar province of Iraq.
Arguments about duration are often of great historical significance, going far beyond the battles of mere hindsight. For instance, the conventional wisdom among historians holds that United States military intervention in Europe in 1917 had the salutary effect of persuading the German high command that, with another fresh and well-equipped force deployed against it, it could not hope to prevail against the British and French alliance. But another explanation of the same events shows the war on the Western Front actually being prolonged. Before President Woodrow Wilson abandoned neutrality and committed American forces in strength, the Germans had been fighting with exceptional success. Their prowess had led to calls, especially in London, for a negotiated peace. But the arrival of a new ally dissipated all such talk and compelled the Germans to fight until the bitter end. Not only that, but when peace terms were finally discussed, the French were allowed and enabled to press their most vindictive economic and territorial claims against Germany. That the Versailles Treaty led to the rise of Naziism and thus to the “Second” World War, or rather Part 2 of the first one, is a conclusion that few historians now dispute. So short-war advocates should know to beware of what they ask for.
A final objection to the dogma of brief engagements is more commonsensical. On the whole, perhaps it is best not to tell your opponent in advance of the date when you plan to withdraw your forces. Many American generals, we understand, were critical of the president’s original decision to announce a deadline for the endgame in Afghanistan. Certainly, there seem to be upsetting signs of Afghan national army units, in particular, basing their calculations on who can be counted on to be still present as the months go by. Difficult to blame people for consulting their own self-interest in this blunt way.
Human history seems to register many more years of conflict than of tranquillity. In one sense, then, it is fatuous to whine that war is endless. We do have certain permanent enemies—the totalitarian state; the nihilist/terrorist cell—with which “peace” is neither possible nor desirable. Acknowledging this, and preparing for it, might give us some advantages in a war that seems destined to last as long as civilization is willing to defend itself.
3D printing technology is a fast and affordable way to build 3D models for neurosurgical planning. Radiologists are able to transform ultra high-resolution CT patient images into 3D solid models using a 3D color printer commonly used in architecture, engineering and construction.
An advantage of 3-D models is that they identify defects that 2-D images do not, which helps radiologists view a clearer impression of the image. With increasing frequency, surgeons and other physicians, and patients alike, request assistance from radiologists in order to identify complex morphologies demonstrated on imaging studies.
"We are applying a technique that has many uses in other industries to aid surgeons in planning procedures on complicated anatomy and pathology as well as help them communicate with patients and their families. Tripler doctors were sending data from Hawaii to the mainland US to have models made at great expense and considerable time. Other radiologists may find these resources in an architect's office or at a factory using 3D printing to make prototypes for just about anything you can fit in a shoebox," said Michelle Yoshida, MD, one of the authors of the exhibit.
Numarul exact al speciilor care vietuiesc in mediul marin (oceanic) e necunoscut. Ultimele evaluari se refera la 250.000-300.000 de specii, altele la peste 1 milion. O socanta imprecizie pentru un domeniu stiintific. Lumea vie din adancurile marine e repertoriata de 250 de ani, evident, cu erori de apreciere in ceea ce priveste numarul speciilor cat si descrierea lor, unele dintre ele avand peste 10 nume stiintifice. Au fost repertoriate aproximativ 14.700 de specii de pesti, 110 de mamifere, 40.000 de crustacee, 650.000 de moluste...
Progresele inregistrate in genetica moleculara au permis, in unele cazuri, corectarea confuziilor. Dincolo de lumea (cvasi) cunoscuta, se profileaza cea care urmeaza sa fie descoperita, de la vertebrate la microorganisme. In 1992, cercetatorii americani au descoperit 798 de animale diferite la o adancime de 2100 metri in largul coastelor statului New Jersey. Prin extrapolare, se deduce faptul ca la adancimi mai mari, pot exista milioane de specii (doar nematodele ajung la 1 milion de specii).
O „bormasina” unica in lume
In momentul in care balenele mor, corpurile lor coboara in abisuri fiind devorate de pesti. Cand nu mai raman decat oasele, apare... osedax, un vierme in forma de tub de 2-5 milimetri care are capacitatea de a perfora osul, deschizand portile bacteriilor specializate in degradarea compusilor organici complecsi. Microorganisme ce constituie hrana viermilor. Aceasta asociatie simbiotica intr-un mediu sulfurat, fara oxigen, e unica in lumea animala. Oamenii de stiinta sunt interesati de misteriosul osedax (au fost identificate pana acum 4 specii) care apare in toate oceanele si la toate adancimile. Nu se stie cum se deplaseaza, dar apare intotdeauna cand e un os de ros.
Ucigasi virali
„Invizibilii” virusi marini (50-200 de nanometri) sunt, de departe, cele mai numeroase vietuitoare ale oceanului planetar, cu o concentratie la 1 litru de apa de 5-25 de ori mai mare decat cea a bacteriilor. Date recente atesta faptul ca infectiile virale ucid 80% din organismele celulare, asigurand o doza semnificativa de nutrimente organice. Virusii au, deopotriva, un rol important in asigurarea diversitatii biologice a planctonului.
Fascinantul creuzet din adancuri
Marea Iroise, limitata la nord de insula Ouesand si arhipelagul Molene iar la sud de insula Sein, e un spatiu aparte, cu un relief submarin accidentat ce ofera o fauna acvatica bogata si o diversitate de habitate unica in Europa. Un loc de care marinarii se tem. Platoul marin cu formatiuni de granit ascutite, cu o suprafata de 135 km2, e acoperit de ape adanci de 5-50 metri. Printre stancile de granit se deplaseaza cei mai violenti curenti din Europa. (Fluxul si refluxul apelor ating 15 km/h.) In acest creuzet marin apele sunt atat de rascolite incat nu se incalzesc niciodata. Intre fundurile sedimentare si stancoase traiesc 350 de specii de alge, 300 de specii de moluste si 126 de specii (cunoscute) de pesti si zece specii de mamifere.
O picatura dintr-un ocean
Sute de specii de vietuitoare marine necunoscute (corali moi, crustacee, amfipode, viermi) au fost descoperite recent in Marea Bariera de Corali din largul coastelor australiene, in cadrul unui program international de recensamant al vietii submarine. O mare varietate a viului, niciodata descrisa de biologi si asta in ape accesibile. Inca un prilej de a constata ca ceea ce se stie despre viata din adancurile apelor reprezinta o picatura dintr-un ocean. Printre animalele descoperite figureaza creveti cu clesti mai mari decat corpul lor si cateva specii de izopode care se hranesc cu pesti morti, denumite si „vulturi de mare”, unele dintre ele hranindu-se in special cu... limba pestilor vii.
Nel 2008, infatti, sono stati ben 3.284 i cicli eseguiti con gameti femminili crioconservati. A decretare il primato è il primo rapporto sull’impiego degli ovociti scongelati condotto dallo European IVF Monitoring Group (Eim) dell’Eshre (European Society of Human Reproduction and Embryology).
I dati sono stati presentati oggi, durante il 27esimo meeting annuale dell’Eshre, in corso a Stoccolma, e mostrano un enorme divario tra la nostra esperienza e quella degli altri paesi. Dopo l’Italia, infatti, seguono la Finlandia con appena 325 cicli, la Russia con 220 e la Spagna con 199 (dati sempre riferiti al 2008).
Fino a oggi il recupero di ovociti congelati non era stato monitorato a livello europeo perché, come dimostrano chiaramente i numeri, si tratta di una tecnica poco diffusa a livello globale. Da qualche tempo a questa parte, però, se ne parla sempre più: il congelamento degli ovociti, infatti, rappresenta oggi una chance di conservare la fertilità per le donne che devono sottoporsi a terapie (come quelle oncologiche) e per quelle che - per scelta personale o motivi socio-economici - decidono di ritardare il momento in cui avere un bambino.
“In Italia siamo ben consapevoli di questo primato e di questi numeri, visti gli obblighi della legge 40, che dal 2004 ha vietato la crioconservazione degli embrioni”, ha commentato Andrea Borini, direttore scientifico del centro di fecondazione assistita Tecnobios Procreazione. “In cinque anni – ha continuato Borini – il congelamento e il recupero degli ovociti crioconservati sono diventate tecniche di routine, tanto che i bambini nati in Italia da ovociti congelati dal 2005 al 2009 sono circa 1.170. Va però sottolineato che le cose stanno già cambiando. Dalla sentenza della Corte Costituzionale 151 del 2009, infatti, il numero di ovociti congelati si è ridotto a favore della crioconservazione degli embrioni, come ha rilevato anche il Registro Nazionale Pma (Vedi Galileo, "Quanti sono i figli della provetta").
Al convegno dell’Eshre sono stati anche presentati gli ultimi dati raccolti a livello mondiale (questa volta per il 2007) dall’International Committee for Monitoring Assisted Reproductive Technologies (Icmart). Ed emergono altri due primati: quello della Spagna per la sua quota del 30% delle ovodonazioni europee, e quello della Svezia per la più bassa frequenza di parti multipli (non solo in Europa, ma nel mondo, con il 7% di parti gemellari e lo 0,1% di trigemini).
“Anche per quanto riguarda le gravidanze e i parti multipli abbiamo risentito molto della legge 40”, commenta ancora Borini: “L’obbligo a impiantare contemporaneamente nell’utero tutti gli embrioni formatisi, per un numero massimo di tre, non poteva certo portare a una diminuzione delle gravidanze trigemine. La sentenza della Consulta ha però eliminato anche questo vincolo e, come conseguenza, la nostra media di parti trigemini si sta avvicinando a quella europea”.
Alla Svezia tengono testa anche la Finlandia e l’Austrialia. Nel 2007, in Spagna, l’incidenza di parti gemellari toccava il 23,8% e in Italia il 21,1%. La media europea per i parti gemellari risulta del 20,6% e per i trigemini dell’1,1%.
Ultimo sguardo all’accesso alla Pma nei vari paesi. Secondo il rapporto, i cicli che si eseguono in Francia (5.464), Italia (4.015), Spagna (3.845), Paesi Bassi (6.382), Germania (4.810) e Gran Bretagna (4.066) sono ancora bassi rispetto a quelli delle nazioni del Nord Europa, come la Svezia (9.228), la Norvegia (9.287), la Danimarca (12.712) e la Finlandia (9.291).
A new analysis by researchers at Lawrence Berkeley National Laboratory (Berkeley Lab) now is challenging that notion, one widely held in both the United States and China.
Well before mid-century, according to a new study by Berkeley Lab's China Energy Group, that nation's energy use will level off, even as its population edges past 1.4 billion. "I think this is very good news,'' says Mark Levine, co-author of the report, "China's Energy and Carbon Emissions Outlook to 2050," and director of the group. "There's been a perception that China's rising prosperity means runaway growth in energy consumption. Our study shows this won't be the case." Along with China's rise as a world economic power have come a rapid climb in energy use and a related boost in human-made carbon dioxide emissions. In fact, China overtook the United States in 2007 as the world's leading emitter of greenhouse gases.
Yet according to this new forecast, the steeply rising curve of energy demand in China will begin to moderate between 2030 and 2035 and flatten thereafter. There will come a time -- within the next two decades -- when the number of people in China acquiring cars, larger homes, and other accouterments of industrialized societies will peak. It's a phenomenon known as saturation. "Once nearly every household owns a refrigerator, a washing machine, air conditioners and other appliances, and once housing area per capita has stabilized, per household electricity growth will slow,'' Levine explains.
Similarly, China will reach saturation in road and rail construction before the 2030-2035 time frame, resulting in very large decreases in iron and steel demand. Additionally, other energy-intensive industries will see demand for their products flatten.
The Berkeley Lab report also anticipates the widespread use of electric cars, a significant drop in reliance on coal for electricity generation, and a big expansion in the use of nuclear power -- all helping to drive down China's CO2 emissions. Although China has temporarily suspended approvals of new nuclear power plant construction in the wake of the disaster at Japan's Fukushima Daiichi Nuclear Power Station, the long-range forecast remains unchanged.
Key to the new findings is a deeper look at patterns of energy demand in China: a "bottom-up" modeling system that develops projections of energy use in far greater detail than standard methods and which is much more time- and labor-intensive to undertake. Work on the project has been ongoing for the last four years. "Other studies don't have this kind of detail,'' says Levine. "There's no model outside of China that even comes close to having this kind of information, such as our data on housing stock and appliances." Not only does the report examine demand for appliances such as refrigerators and fans, it also makes predictions about adoption of improvements in the energy efficiency of such equipment -- just as Americans are now buying more efficient washing machines, cars with better gas-mileage, and less power-hungry light bulbs.
Berkeley Lab researchers Nan Zhou, David Fridley, Michael McNeil, Nina Zheng, and Jing Ke co-authored the report with Levine. Their study is a "scenario analysis" that forecasts two possible energy futures for China, one an "accelerated improvement scenario" that assumes success for a very aggressive effort to improve energy efficiency, the other a more conservative "continued improvement scenario" that meets less ambitious targets. Yet both of these scenarios, at a different pace, show similar moderation effects and a flattening of energy consumption well before 2050.
Under the more aggressive scenario, energy consumption begins to flatten in 2025, just 14 years from now. The more conservative scenario sees energy consumption rates beginning to taper in 2030. By the mid-century mark, energy consumption under the "accelerated improvement scenario" will be 20 percent below that of the other.
Scenario analysis is also used in more conventional forecasts, but these are typically based on macroeconomic variables such as gross domestic product and population growth. Such scenarios are developed "without reference to saturation, efficiency, or usage of energy-using devices, e.g., air conditioners,'' says the Berkeley Lab report. "For energy analysts and policymakers, this is a serious omission, in some cases calling into question the very meaning of the scenarios.''
The new Berkeley Lab forecast also uses the two scenarios to examine CO2 emissions anticipated through 2050. Under the more aggressive scenario, China's emissions of the greenhouse gas are predicted to peak in 2027 at 9.7 billion metric tons. From then on, they will fall significantly, to about 7 billion metric tons by 2050. Under the more conservative scenario, CO2 emissions will reach a plateau of 12 billion metric tons by 2033, and then trail down to 11 billion metric tons at mid-century.
Several assumptions about China's efforts to "decarbonize" its energy production and consumption are built into the optimistic forecasts for reductions in the growth of greenhouse gas emissions. They include:
A dramatic reduction in coal's share of energy production, to as low as 30 percent by 2050, compared to 74 percent in 2005
An expansion of nuclear power from 8 gigwatts in 2005 to 86 gigawatts by 2020, followed by a rise to as much as 550 gigawatts in 2050
A switch to electric cars. The assumption is that urban private car ownership will reach 356 million vehicles by 2050. Under the "continued improvement scenario," 30 percent of these will be electric; under the "accelerated improvement scenario," 70 percent will be electric.
The 72-page report by Levine and colleagues at Berkeley Lab's Environmental Energy Technologies Division was summarized in a briefing to U.S. Congressional staffers. The study was carried out under contract with the U.S. Department of Energy, using funding from the China Sustainable Energy Program, a partnership of the David and Lucile Packard Foundation and the Energy Foundation.
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