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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.

Source: ScienceDaily

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By Admin (from 29/09/2011 @ 11:00:32, in ro - Observator Global, read 574 times)

 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.

DORIN MARAN - magazin.ro

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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).

Detail-ovociti congelati

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).

Fonte: galileonet.it - Riferimento: "For the first time, the European IVF Monitoring Group reports on cycles using frozen eggs" - Via Tecnobios Procreazione

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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.
 
Source: ScienceDaily

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By Admin (from 28/09/2011 @ 11:00:15, in ro - TV Network, read 658 times)

 Adevarata drama a unui om cu personalitate puternica este incapacitatea de a se pune de acord cu el însusi. Din acest izvor nefericit tasnesc obstacolele pe care le întampina acea personalitate în a accepta ceea ce au facut altii demn de luat în seama, fie ca acei „altii” se numesc Iisus Christos, Dante Alighieri sau Isaac Newton. Analiza moderna a unui artist de mare talent precum englezul William Blake (1757-1827) nu poate exclude o scurta incursiune freudiana în copilaria personajului. Numai ca pustiul Blake nu a fost abuzat în vreun fel de parinti, ci traumatizat de vedenii mistico-religioase.

Atunci cand propriul tau copil îti spune ca a vazut la fereastra „capul lui Dumnezeu” (la patru ani!), iar pe la opt ani a observat ca „albinele dintr-un copac s-au transformat în îngeri stralucitori”, înseamna ca ai de-a face cu o alunecoasa dilema: fie ca este vorba despre o imaginatie superfecunda, fie ca un derapaj psihic este deja instalat, cu o incredibila precocitate. Din tot ceea ce am citit despre interesantul domn Blake reiese ca ambele variante sunt plauzibile...

Poet, gravor, pictor si filosof al religiei, William Blake a fost un fel de extraterestru caruia nu i s-a stabilit planeta de provenienta. „Excesiv de romantic”, „nebun de legat”, „eretic neîmblanzit”, „iluminat glorios”, toate acestea sunt etichetele puse stridentelor manifestari artistico-religioase ale unei personalitati iesite din comun care a vrut sa rescrie Biblia, Infernul lui Dante si conceptiile lui Newton si care „s-a certat cu Iisus Christos”, desi îi recunostea o superioritate dumnezeiasca.

Parea un om care a trecut pe la Judecata de Apoi si prin cele noua cercuri ale Infernului dantesc si s-a întors printre oameni pentru a „retusa” conceptiile eronate sau învechite. Sarmanul domn Blake voia o revolutie spirituala pe care n-a reusit s-o concretizeze decat contrazicandu-i pe altii. Talentul sau de poet si ilustrator de carte (a realizat gravuri pentru toate operele sale) a fost incontestabil, dar singura persoana pe care a convins-o a fost sotia sa, analfabeta Catherine Boucher – care s-a semnat cu un „X” pe certificatul de casatorie.

Rebeliunea din spiritul domnului Blake s-a manifestat si în casnicie. Dansul nu întelegea de ce sotia nu accepta o concubina în caminul conjugal. Dupa aprige si uneori contondente divergente, iubitele lui Blake nu au trecut pragul usii. Consolata, doamna Blake a început treptat sa înteleaga, avea un barbat vizionar si s-a decis sa aiba si ea „unele viziuni”, ba mistice, ba laice, în care sotul ei aparea ca salvator al omenirii. Printre versurile filosofic-înfierbantate care au miscat-o profund au fost si urmatoarele: „Închisorile sunt construite cu pietre ale legii, iar bordelurile cu pietre ale religiei” (din cartea „Proverbele Infernului”).

Aceeasi doamna Blake si-a încurajat barbatul sa dea de pamant cu profetiile biblice si sa elaboreze propriile sale viziuni, intitulate „Casatoria Infernului cu Paradisul”. Curajul novator al domnului Blake a atins apogeul cand a scris „Evanghelia nemuritoare” (The Everlasting Gospel), în care Christos nu este o prezenta mesianica si nici filosofica, ci doar o „creatie suprema”. Nu e de mirare ca domnul si doamna Blake au comunicat fecund si dupa moarte, dand un bobarnac constructiv celor care s-au îndoit vreodata de autenticitatea revolutiei spirituale promovate de neîntelesul poet lumilor profunde. Atat de profunde, încat de mormantul sau s-a ales praful si se cauta si acum un loc pentru piatra sa tombala.

Autor: PAUL IOAN - magazin.ro

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L’iniziativa, che prende il nome di TRY, è frutto della collaborazione di 106 istituti di ricerca ed è stata promossa dall’Istituto di Biogeochimica Max Planck di Jena in Germania con la collaborazione dell’Università di Leipzig (Germania), l’IMBIV-CONICET (Argentina), l’Università di Macquarine (Australia), il CNRS e l’Università di Parigi-Sud (Francia).

Detail-try

Le proprietà morfologiche e fisiologiche delle piante permettono di comprendere il modo in cui esse riescono a sfruttare le risorse naturali quali l’acqua, la luce e le varie sostanze nutrienti della terra per regolare il loro sviluppo. Ma la vera innovazione sta nel prevedere, a seconda delle loro caratteristiche, il modo in cui influenzeranno l’ecosistema stesso, per esempio calcolando quanta CO2 riescono ad assorbire.
Finora, infatti, gli studi sul cambiamento climatico non avevano potuto contare su una larga mole di dati a proposito delle specie vegetali. Una lacuna che la prima versione del database aiuta in parte a colmare: la classificazione creata, infatti, permette non solo di immaginare quale potrà essere l’effetto sul cambiamento climatico del futuro, ma dà anche gli strumenti per trovare, già da adesso, accorgimenti che possono contenere e limitare in modo mirato le alterazioni del clima.

“La possibilità di avere a disposizione una così vasta banca dati consentirà di fare delle previsioni più accurate su come la vegetazione e le proprietà degli ecosistemi muteranno in conseguenza dei cambiamenti futuri del clima e dello sfruttamento del suolo”, ha spiegato Ian Wright della Macquarie University. Per questo i ricercatori, come scrivono sulle pagine di Global Change Biology, sono convinti che il database TRY rivoluzionerà la ricerca nel campo della biodiversità.

Fonte: galileonet.it - Riferimenti: Global Change Biology DOI: 10.1111/j.1365-2486.2011.02451.x

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By Admin (from 27/09/2011 @ 14:00:02, in it - Scienze e Societa, read 580 times)

Le isole Andamane, in India, sono una meta sempre più popolare. Spiagge bianche, mare cristallino, barriere coralline. Ma il turismo, in questa parte di mondo, ha un che di kafkiano. Ogni mese, migliaia di visitatori non solo indiani, ma provenienti da tutto il mondo, percorrono la Andaman Trunk Road attratti dalla possibilità di vedere la tribù dei Jarawa, in quello che somiglia molto a uno zoo safari umano. I tour operator locali, infatti, attirano fuori dalla foresta i Jarawa con biscotti e dolciumi, per permettere ai turisti di vederli e fotografarli. Con il risultato di esporre la popolazione, che conta solo 365 individui, al rischio di malattie e di incidenti stradali.

Detail-andaman trunk

Contro l’assurdità di queste escursioni organizzate, Survival International ha lanciato una campagna di boicottaggio.
Da quando fu realizzata negli anni Settanta, la superstrada Andaman Trunk ha semplificato la vita di bracconieri, coloni e taglialegna che depredano la selvaggina della tribù e ne minacciano la sopravvivenza. I cacciatori-raccoglitori Jarawa, infatti, sono in contatto con l’esterno solo dal 1998 e hanno poche difese immunitarie contro le malattie più comuni, a causa del lungo isolamento. Non è tutto: come sottolinea Survival, nella riserva sono stati denunciati anche casi di abuso sessuale e il safari è l’ultimo di una serie di affronti inumani a questa popolazione.

Per proteggere gli Jarawa, nel 2002 la Corte Suprema dell’India ha ordinato la chiusura della strada, che però risulta tuttora aperta illegalmente, e rappresenta una meta ambita per i villeggianti. “Il viaggio nella riserva tribale era come un vero e proprio safari: stavamo nel mezzo della foresta tropicale in attesa di vedere gli animali selvatici o, per essere precisi, i Jarawa”, ha riportato un turista. I più attratti dal cibo lanciato dai passeggeri dei veicoli in marcia sulla strada sono i bambini, che spesso restano coinvolti in incidenti stradali. Per questo Survival, insieme all’associazione locale Search, chiede ai turisti di boicottare queste escursioni.

La campagna, lanciata già lo scorso anno, finora ha ottenuto un discreto successo e diversi tour operator hanno smesso di promuovere gite nella riserva degli Jarawa; autisti indipendenti e altre compagnie, però, continuano a usare la terra nativa di questa tribù come un parco safari. “Oggi chiediamo a tutti i turisti di rifiutarsi di percorrere la strada delle Andamane, tenuta aperta dall’amministrazione locale in palese sprezzo dell’ordine della Corte Suprema dell’India”, ha dichiarato Stephen Corry, direttore generale di Survival. “Nonostante le direttive, i turisti continuano a invadere il territorio dei Jarawa mettendo a rischio le loro vite e trattandoli come animali. Se la situazione non cambierà, promuoveremo un boicottaggio del turismo in tutte le Isole Andamane”, ha aggiunto Corry.

Fonte: Survival International

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The question they may want to ask instead is how can they prevent their child from becoming a bully.

New research to be presented on Sunday, May 1, at the Pediatric Academic Societies (PAS) annual meeting in Denver shows that parents can play a key role in decreasing the chances that their son or daughter will harass or intimidate other children.

Researchers, led by Rashmi Shetgiri, MD, FAAP, examined the prevalence of bullying reported by parents who took part in the National Survey of Children's Health from 2003-2007. They also looked at factors that were associated with an increased or decreased risk that a child bullied others.

The survey showed nearly one in six youths 10-17 years old bullied others frequently in 2007, according to Dr. Shetgiri, assistant professor of pediatrics at University of Texas Southwestern Medical Center and Children's Medical Center, Dallas. While the rates of parents who reported that their children harassed others frequently (defined as sometimes, usually or always) decreased from 2003 to 2007, these rates remain high, Dr. Shetgiri said.

Survey results also showed that 23 percent of children had bullied another youngster in 2003 compared to 35 percent in 2007.

Some factors that increase the likelihood that a child will bully others have persisted from 2003 to 2007. For example, children are more likely to be bullies if their parents frequently feel angry with them or feel their child bothers them a lot. In addition, children with an emotional, developmental or behavioral problem and those whose mothers report less than very good mental health also are more likely to be bullies. In fact, about one in five bullies has an emotional, developmental or behavioral problem, more than three times the rate in non-bullies, Dr. Shetgiri noted.

Other factors that seem to protect a child from becoming a bully also have persisted from 2003 to 2007. Parents who share ideas and talk with their child, and who have met most or all of their child's friends are less likely to have children who bully, Dr. Shetgiri said.

"Targeting interventions to decrease these persistent risk factors and increase the persistent protective factors could lead to decreased bullying," she said.

For example, parents can increase involvement with their children by meeting their friends and by spending time talking and sharing ideas with their children, Dr. Shetgiri suggested. "They also can find effective ways to manage any feelings of anger toward their child and can work with health care providers to make sure any emotional or behavioral concerns they have about their child, as well as their own mental health, are addressed."

Source: MedicalXpress.com

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 O echipa de cercetatori francezi de la Institutul Pasteur a demonstrat faptul ca numeroase zone ale creierului sunt capabile sa produca noi neuroni cu ajutorul celulelor gliale. Celulele gliale au fost descoperite in 1891 de medicul spaniol Santiago Ramon Y Cajal. Acest cercetator deosebit de prolific a pus in evidenta caracterul celular al neuronilor. Studiile sale, recompensate cu Premiul Nobel pentru Medicina in 1906, au scos in evidenta existenta celulelor gliale, de 9 ori mai numeroase decat neuronii, care joaca un rol important in transmisia influxului nervos si care, contrar neuronilor, sunt capabile sa se reproduca. Proportia dintre celulele gliale si neuroni a dat nastere, in urma unei erori jurnalistice, ideii care s-a infiltrat in opinia publica, conform careia oamenii folosesc doar 10% din creier.

Functiile celulelor gliale sunt putin cunoscute. Li se atribuie rolul organizarii conexiunilor neuronale, adica, facultatii neuronilor de a produce noi sinapse. In acest sens s-a demonstrat recent ca practica intensiva a jocului la micile mamifere duce la o crestere a numarului celulelor gliale in raport cu subiectii care nu practica acest „sport”. Cat priveste fiintele umane, e de semnalat faptul ca creierul lui Einstein avea un numar anormal de mare de celule gliale la nivelul lobilor parietali.

Prabusirea unei dogme

 Cercetatorii (neurobiologi) erau convinsi ca neuronii creierului uman sunt capabili sa se multiplice. Pana in 2003, cand o echipa de cercetatori francezi a descoperit faptul ca unele categorii de celule gliale se puteau transforma in neuroni capabili sa se insereze in tesutul neuronal existent. In 2004, aceeasi echipa, in colaborare cu specialisti germani, a demonstrat ca o molecula secretata de bulbul olfactiv (tenascina) are facultatea de a atrage neuronii imaturi, care se transforma in veritabili neuroni.

Dispozitive de regenerare

O noua etapa in descifrarea activitatii cerebrale a fost astfel parcursa. Aceeasi echipa de cercetatori a mai demonstrat faptul ca celulele suse (stem) gliale se repartizeaza nu doar in zona de formare ci si de-a lungul unui tunel prin care migreaza noii neuroni si in bulbul olfactiv. Demonstratia a fost facuta utilizandu-se un marcator fluorescent vehiculat de un vector viral capabil sa vizeze celulele gliale. Transformarea acestora in neuroni era intensificata in urma unei leziuni care ducea la pierderea simturilor olfactive, o dovada clara a capacitatii de autoreparare a creierului. Deturnandu-se neuronii nou formati din zona lor germinativa spre regiunile lezate, constituie o strategie terapeutica extraordinara si o speranta pentru tratarea unor patologii neurodegenerative ale sistemului nervos central.

Brate miscate prin puterea gandului

In urma realizarii unei conexiuni artificiale intre creier si mana, o maimuta macac afectata de o paralizie temporara a unui brat, a reusit intr-un timp foarte scurt sa-si reia miscarea bratului. Pentru a conferi mobilitate unui brat paralizat in urma sectiunii unei legaturi nervoase sau dupa un soc care a atins coloana vertebrala, se poate imagina o noua conexiune intre zona motrice a creierului (legata de maduva spinarii) si muschi, asa cum un electrician ar instala un nou fir electric. Deocamdata medicii sunt departe de a realiza aceasta minune. Primele incercari in acest sens au fost insa facute. Acum e posibil, de pilda, sa se detecteze semnalul care parcurge o legatura nervoasa sau care parvine din activitatea neuronilor creierului.

Unele experimente realizate au avut ca scop controlul unor proteze sau a calculatorului prin forta gandului. Pe acest drum extrem de dificil s-a inscris cu succes o echipa de cercetatori americani de la Universitatea din Washington care a pus la punct un dispozitiv ce conecteaza prin intermediul calculatorului, cortexul motor al creierului de muschii mainii. Realizata in cazul a doua maimute cu un brat temporar paralizat (sub anestezie locala), experienta le-a permis, dupa mai multe incercari, ca muschii mainii sa fie comandati de creier.

Electrozii au fost bransati pe neuroni izolati din cortexul maimutelor care nu aveau functia de a comanda muschii! Pentru a verifica functionarea acestora, cercetatorii au cuplat sistemul la un monitor. Prin semnalele trimise de electrozi, detectate de calculator, a fost posibila deplasarea cursorului pe ecran. Experimentul a fost transformat intr-un joc in care maimutele trebuiau sa dirijeze cursorul spre un patrat, reusita fiind recompensata cu dulciuri.

Dependenta de droguri

Mecanismele cerebrale ale dependentei nu sunt, probabil, cele stiute. Recentele studii ale unui specialist francez (Jean-Paul Tassin) repun in discutie aceasta problema. Este vorba de o noua viziune care permite reconsiderarea procesului de dependenta de tutun, alcool, droguri, jocuri de noroc etc. In 1998, in urma studiilor a doi cercetatori italieni, s-a ajuns la concluzia ca toate drogurile provoaca eliberarea de dopamina intr-o regiune a creierului denumita nucleu acumbens. Dependenta era pusa pe seama faptului ca circuitul cerebral asa zis „al recompensei”, care gestioneaza satisfacerea nevoilor noastre vitale, e total perturbat de eliberarea masiva a mesagerului ei principal, dopamina. In acest caz, creierul nostru considera drogul ca fiind esential in satisfacerea nevoilor.

Echipa de cercetatori francezi propune o alta teorie care ar putea revolutiona acest domeniu permitand totodata sa rezolve „fragilitatea” modelului „oficial” al dopaminei. Tassin considera ca toate drogurile – alcool, morfina, amfetamine, cocaina etc. – distrug legatura intre cei doi neurotransmitatori, noradrenalina si serotonina, doua molecule care se gasesc din abundenta in cortex si in sistemul limbic, perturband activitatea acestora, ceea ce face ca orice emotie traita de toxicoman sa fie foarte puternica. Cand noradrenalina se epuizeaza in urma nevoii de drog, moralul toxicomanului se prabuseste iar interesul social dispare.

Dependenta apare in momentul in care se produce o decuplare intre acesti doi neurotransmitatori. Decuplat, sistemul nu mai poate asigura controlul emotiilor, provocand o hiperemotivitate care il impinge pe subiect spre drog.

DORIN MARAN - magazin.ro

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Overview of the theory

One theory of the origin of AIDS is that it developed from contaminated vaccines used in the world's first mass immunisation for polio. There are a number of reasons why this theory is plausible enough to be worthy of further investigation.

  • The location coincides dramatically. The earliest known cases of AIDS occurred in central Africa, in the same regions where Koprowski's polio vaccine was given to over a million people in 1957-1960.
  • The timing coincides. There is no documented case of HIV infection or AIDS before 1959. Centuries of the slave trade and European exploitation of Africa exposed Africans and others to all other diseases then known; it is implausible that HIV could have been present and spreading in Africa without being recognised.
  • Polio vaccines are grown (cultured) on monkey kidneys which could have been contaminated by SIVs. Polio vaccines could not be screened for SIV contamination before 1985.
  • Another monkey virus, SV-40, is known to have been passed to humans through polio vaccines. A specific pool of Koprowski's vaccine was later shown to have been contaminated by an unknown virus.
  • In order for a virus to infect a different species, it is helpful to reduce the resistance of the new host's immune system. Koprowski's polio vaccine was given to many children less than one month old, before their immune systems were fully developed. Indeed, in one trial, infants were given 15 times the standard dose in order to ensure effective immunisation.

If this theory is correct, it has serious ethical, health and policy implications. In particular, it points to the danger of interspecies transfer of material through vaccinations, organ transplants, etc., which could lead to new variants of AIDS as well as other new diseases. As well, studying the theory may lead to insights about responding to AIDS and preventing new diseases.

On several occasions, critics have claimed that the theory has been refuted. The Wistar Committee in 1992 said the death of a British sailor in 1959, whose tissues later tested positive for HIV, made the theory implausible. However, several years later, more sensitive tests showed no HIV in the tissues.

In 2001, reports were published that polio vaccine samples held in Philadelphia from the 1950s showed no immunodeficiency viruses. This was trumpeted as a refutation of the theory. Edward Hooper later produced evidence that US-produced vaccines had been amplified in Africa using chimpanzees as a substrate, thus showing the theory could be correct.

Scientists have spent a lot of effort trying to refute the polio-vaccine theory of the origin of AIDS, but very little trying to refute the conventional view, that blood from an SIV-infected chimpanzee got into humans via hunting or eating. There is very little direct evidence to support the conventional view, which explains neither the timing nor the location of the origin.

Scientific journals have been reluctant to publish articles about the polio-vaccine theory. For example, Nature has received substantial submissions about the theory from at least six scholars but has not published any of them. Opponents of the theory have used defamation threats and legal actions to discourage publication. The result is that editorial prerogative and legal action have given the false impression that critics of the theory have been unanswered.

To help rectify this situation, key documents presenting the theory and commenting on it are provided here. Also given is a list of publications about the theory. This material is provided by Brian Martin who as a social scientist has been following the origins debate since 1991. It is part of a page on suppression of dissent. Comments and additional contributions are welcome.

 

Some key publications about the theory
(in reverse chronological order) 

 

BOOKS

Edward Hooper, The River: A Journey Back to the Source of HIV and AIDS (Harmondsworth: Penguin; Boston: Little, Brown, 1999; revised edition, Penguin, 2000). This is an enormous but highly readable scientific blockbuster, providing the most detailed examination of the polio vaccine theory yet available, including many new findings. It has generated widespread discussion and debate and has established the polio-vaccine theory of the origin of AIDS as by far the strongest contender to the cut-hunter orthodoxy.

The River is available in a CD-ROM edition: see http://www.aidsorigins.com/content/view/206/28/

Omar Bagasra, HIV and Molecular Immunity: Prospects for the AIDS Vaccine (Natick, MA: Biotechniques Books, 1999). This technical scientific book presents a new theory of molecular immunity for the origin and history of HIV-1, which, it is argued, most likely derived from polio vaccinations in Africa.
Kiley R. Prilliman reviews the book in the prestigious journal Cell. Julian Cribb has provided insightful comments on the book for nonspecialists. The author, Omar Bagasra, can be contacted at omarb@sc.rr.com. The book is available from Eaton Publishing, 154 East Central Street, Natick MA 01760, USA, phone 508-653 6272, fax 508-653 2706.

Julian Cribb, The White Death (Sydney: Angus & Robertson, 1996). An engaging book focussing on both the polio-vaccine-AIDS theory and its reception by the scientific community. Full text available.

 

ARTICLES

Edward Hooper has his own website, http://www.aidsorigins.com/. See it for his latest contributions. March 2008: two articles on Michael Worobey's research.

Brian Martin, "Contested testimony in scientific disputes: the case of the origins of AIDS", The Skeptic, Vol. 13, No. 3, 2007, pp. 52-58.

Christian Biasco has written a predoctoral thesis analysing the origin-of-AIDS controversy: The origin of AIDS: an hermeneutical analysis of the scientific publications. University of Geneva, July 2006. He has also written a play about the origin of AIDS titled The Seeds of Doom. You can read the text of the play in Italian and English and see the play in Italian with subtitles.

Edward Hooper, commentaries, February-August 2006

New material about the origin of AIDS published in November 2005 in Narrow Roads of Gene Land: The Collected Papers of W. D. Hamilton, Volume 3: Last Words, edited by Mark Ridley, Oxford University Press.

Brian Martin, "The Politics of a Scientific Meeting: the Origin-of-AIDS Debate at the Royal Society", Politics and the Life Sciences, Vol. 20, No. 2, September 2001, pp. 119-130 [published 2005]. Also available in pdf.

Edward Hooper, commentaries, October-November 2004

 

April 2004: Is the contaminated polio vaccine theory refuted?

Yes: Michael Worobey et al., "Contaminated polio vaccine theory refuted", Nature, Vol. 428, 22 April 2004, p. 820. 
No: a reply by Edward Hooper, "Contaminated polio vaccine theory not refuted", April 2004. 
Worobey et al. supplementary information and map. Hooper's comments. 
Hooper gives further comments, and a short version of further comments.

Edward Hooper, "The dirty side of the origin-of-AIDS debate": a series of commentaries, February-March 2004.

 Stanley A. Plotkin, "Chimpanzees and journalists" (editorial), Vaccine, Vol. 22, 2004, pp. 1829-1830. Introduction to Osterrieth's article.

Paul Osterrieth, "Oral polio vaccine: fact versus fiction", Vaccine, Vol. 22, 2004, pp. 1831-1835. Denial of Hooper's claims about production of polio vaccine in Africa.


Lincei meeting papers
Origin of HIV and Emerging Persistent Viruses,
Rome, 28-29 September 2001
Published as Atti dei Convegni Lincei, 2003, Vol. 187, ISBN 88-218-0885-8

Maria Luisa Bozzi, "Truth and science: Bill Hamilton's legacy", pp. 21-26.

Edward Hooper, "Dephlogistication, Imperial Display, Apes, Angels, and the Return of Monsieur Émile Zola", pp. 27-230. This massive paper is a response to criticisms of The River, plus new evidence.

Mikkel H. Schierup and Roald Forsberg, "Recombination and phylogenetic analysis of HIV-1" (in pdf), pp. 231-245.

R A Weiss, "Concluding remarks: emerging persistent infections, family heirlooms and new acquisitions" (in pdf), pp. 305-314.


 

Brian Martin, Investigating the origin of AIDS: some ethical dimensions, Journal of Medical Ethics, Vol. 29, No. 4, August 2003, pp. 253-256.

Edward Hooper, "The Story of a Man-Made Disease", April 2003. A shortened version appeared in the London Review of Books, followed by a series of letters to the editor.

Edward Hooper deals with "Opposition to the OPV theory"

Robin Weiss, "Reflections on the origin of human immunodeficiency viruses", AIDS & Hepatitis Digest, January 2002. Critical commentary on the polio-vaccine theory. Robin Weiss can be contacted at <r.weiss@ucl.ac.uk>.


Royal Society Discussion Meeting (and subsequent events)
Origins of HIV and the AIDS Epidemic, London, 11-12 September 2000
Papers, press releases, media stories and responses



Stanley A. Plotkin, 
"CHAT oral polio vaccine was not the source of Human Immunodeficiency Virus Type 1 Group M for humans", Clinical Infectious Diseases, Vol. 32, 2001, pp. 1068-1984. A detailed rebuttal of the claims in Edward Hooper's The River. This is almost the same paper as published in the Royal Society meeting proceedings.

Billi Goldberg and Raphael B. Stricker, "Bridging the gap: human diploid cell strains and the origin of AIDS",Journal of Theoretical Biology, Vol. 204, 2000, pp. 497-503. The hypothesis that polio vaccine produced using human cells was responsible for AIDS.

Brian Martin, "Political refutation of a scientific theory: the case of polio vaccines and the origin of AIDS", Health Care Analysis, Vol. 6, 1998, pp. 175-179. How legal action and editorial decisions mean that the published record gives the misleading impression that the polio-vaccine-AIDS theory has been refuted.

Brian Martin, "Sticking a needle into science: the case of polio vaccines and the origin of AIDS", Social Studies of Science, Vol. 26, No. 2, May 1996, pp. 245-276. A personal account of how the author as a social scientist intervened in the debate over the polio-vaccine-AIDS theory.

Blaine F. Elswood and Raphael B. Stricker, "Polio vaccines and the origins of AIDS", Medical Hypotheses, vol. 42, 1994, pp. 347-354 and Correspondence, vol. 44, 1995, p. 226. This is the first major paper in the scientific literature presenting the theory. Blaine Elswood can be contacted at Blaine.Elswood@snow.edu.

W. D. Hamilton, unpublished letter to Science, 27 January 1994. Hamilton attempted to publish a letter inScience responding to Koprowski's 1992 letter. Included here is both the letter itself and Hamilton's correspondence with Science.

Brian Martin, "Polio vaccines and the origin of AIDS: the career of a threatening idea", Townsend Letter for Doctors, #126, January 1994, pp. 97-100. An account of the theory and its implications.

Rolling Stone, "'Origin of AIDS' update", 9 December 1993, p. 39. Publication of this "Clarification" was part of the settlement of Koprowski's defamation action against Rolling Stone and Tom Curtis.

Brian Martin, "Peer review and the origin of AIDS -- a case study in rejected ideas", BioScience, vol. 43, no. 9, October 1993, pp. 624-627. An account of the theory and the response to it.

B. F. Elswood and R. B. Stricker, "Polio vaccines and the origin of AIDS", Research in Virology, vol. 144, 1993, pp. 175-177. A letter to the editor presenting the theory plus a critical reply from the editorial board. Blaine Elswood can be contacted at Blaine.Elswood@snow.edu.

Louis Pascal, "Preliminary notes concerning shortcomings of a correspondence by Y. Ohta, et al.", 8 May 1993 (previously unpublished). A critique of a scientific paper cited by Koprowski and by Basilico et al. in the case against the polio-vaccine theory.

Tom Curtis, unpublished letter to Science, 30 September 1992. This letter rejected by Science was a response to Koprowski's letter in Science attacking the polio-vaccine theory.

Claudio Basilico et al., Report from the AIDS/Poliovirus Advisory Committee, 18 September 1992. Stimulated by Curtis's article in Rolling Stone, the Wistar Institute set up an independent committee to examine the theory. This is its report, which was never formally published.

Hilary Koprowski, "AIDS and the polio vaccine" (letter), Science, vol. 257, 21 August 1992, pp. 1024, 1026-1027; correction, 11 September 1992, p. 1463. This is a reply to Tom Curtis's article in Rolling Stone and is one of the few published critiques of the theory.

Raanan Gillon, "A startling 19,000-word thesis on the origin of AIDS: should the JME have published it?",Journal of Medical Ethics, vol. 18, 1992, pp. 3-4. The editor of the Journal of Medical Ethics summarises Pascal's argument, explains why JME rejected it, and notes its importance and availability.

Tom Curtis, "The origin of AIDS", Rolling Stone, Issue 626, 19 March 1992, pp. 54-59, 61, 106, 108. This article gave the theory its first wide visibility. Based on a version of the theory developed independently by Blaine Elswood, it was investigated and reported on by Tom Curtis. Tom Curtis can be contacted at tcurtis@utmb.edu.

Louis Pascal, "What happens when science goes bad", Science and Technology Analysis Working Paper #9, University of Wollongong, December 1991. This was the first major published account of the theory. Hard copies are available free from Brian Martin, bmartin@uow.edu.au, on request. Please include your postal address.

Source: uow.edu.au

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Asta e marihoana nu?ei cine te poate opri so faci ,eu nu prefer astfel de fistractie deoarece am vazut ca dupa nu mai faci altceva fecit ca dormi bine,nu am incercat nu incerc dar nu opresc pe nimeni ...
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