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If it sputters, this is caused by the thermal motions of the smallest particles, which interfere with its running. Researchers at the University of Stuttgart and the Stuttgart-based Max Planck Institute for Intelligent Systems have now observed this with a heat engine on the micrometre scale. They have also determined that the machine does actually perform work, all things considered. Although this cannot be used as yet, the experiment carried out by the researchers in Stuttgart shows that an engine does basically work, even if it is on the microscale. This means that there is nothing, in principle, to prevent the construction of highly efficient, small heat engines.

A technology which works on a large scale can cause unexpected problems on a small one. And these can be of a fundamental nature. This is because different laws prevail in the micro- and the macroworld. Despite the different laws, some physical processes are surprisingly similar on both large and small scales. Clemens Bechinger, Professor at the University of Stuttgart and Fellow of the Max Planck Institute for Intelligent Systems, and his colleague Valentin Blickle have now observed one of these similarities.

A Stirling engine in the microworld: In a normal-sized engine, a gas expands and contracts at different temperature and thus moves a piston in a cylinder. Physicists in Stuttgart have created this work cycle with a tiny plastic bead that they trapped in the focus of a laser field. Credit: Fritz Höffeler / Art For Science

"We've developed the world's smallest steam engine, or to be more precise the smallest Stirling engine, and found that the machine really does perform work," says Clemens Bechinger. "This was not necessarily to be expected, because the machine is so small that its motion is hindered by microscopic processes which are of no consequence in the macroworld." The disturbances cause the micromachine to run rough and, in a sense, sputter.

The laws of the microworld dictated that the researchers were not able to construct the tiny engine according to the blueprint of a normal-sized one. In the heat engine invented almost 200 years ago by Robert Stirling, a gas-filled cylinder is periodically heated and cooled so that the gas expands and contracts. This makes a piston execute a motion with which it can drive a wheel, for example.

"We successfully decreased the size of the essential parts of a heat engine, such as the working gas and piston, to only a few micrometres and then assembled them to a machine," says Valentin Blickle. The working gas in the Stuttgart-based experiment thus no longer consists of countless molecules, but of only one individual plastic bead measuring a mere three micrometres (one micrometre corresponds to one thousandth of a millimetre) which floats in water. Since the colloid particle is around 10,000 times larger than an atom, researchers can observe its motion directly in a microscope.

The physicists replaced the piston, which moves periodically up and down in a cylinder, by a focused laser beam whose intensity is periodically varied. The optical forces of the laser limit the motion of the plastic particle to a greater and a lesser degree, like the compression and expansion of the gas in the cylinder of a large heat engine. The particle then does work on the optical laser field. In order for the contributions to the work not to cancel each other out during compression and expansion, these must take place at different temperatures. This is done by heating the system from the outside during the expansion process, just like the boiler of a steam engine. The researchers replaced the coal fire of an old-fashioned steam engine with a further laser beam that heats the water suddenly, but also lets it cool down as soon as it is switched off.

The fact that the Stuttgart machine runs rough is down to the water molecules which surround the plastic bead. The water molecules are in constant motion due to their temperature and continually collide with the microparticle. In these random collisions, the plastic particle constantly exchanges energy with its surroundings on the same order of magnitude as the micromachine converts energy into work. "This effect means that the amount of energy gained varies greatly from cycle to cycle, and even brings the machine to a standstill in the extreme case," explains Valentin Blickle. Since macroscopic machines convert around 20 orders of magnitude more energy, the tiny collision energies of the smallest particles in them are not important.

The physicists are all the more astonished that the machine converts as much energy per cycle on average despite the varying power, and even runs with the same efficiency as its macroscopic counterpart under full load. "Our experiments provide us with an initial insight into the energy balance of a heat engine operating in microscopic dimensions. Although our machine does not provide any useful work as yet, there are no thermodynamic obstacles, in principle, which prohibit this in small dimensions," says Clemens Bechinger. This is surely good news for the design of reliable, highly efficient micromachines.

Source: Max-Planck-Gesellschaft via ZeitNews.org

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Cercetatorii americani sunt cu un pas mai aproape de crearea insectelor-cyborg destinate spionajului, dupa ce o echipa de oameni de stiinta finantata de armata SUA a conceput o baterie speciala, care se alimenteaza cu ajutorul proceselor chimice ce au loc în corpul insectelor.

Bateria atasata permite alimentarea atasamentelor robotice ce au fost fixate pe corpul insectelor.

Armata americană a conceput gândaci-cyborg dotaţi cu baterii (FOTO)

Reusita a fost finantata de aripa de cercetare a armatei americane, DARPA, constituind un pas înainte spre ziua în care insectele vor putea fi dotate cu aparate de înregistrare, senzori si alte dispozitive electronice ce vor permite folosirea acestora ca mini-spioni.

"Albinele au fost folosite pentru detectarea minelor si a armelor de distrugere în masa. Programul nostru are ca scop conceperea de tehnologii care sa permita preluarea controlului asupra locomotiei insectelor, asa cum haturile sunt necesare pentru a controla locomotia cailor", se explica pe site-ul DARPA.

Noua tehnologie, prin care insectele alimenteaza atasamentele electronice folosind procesele chimice din propriul corp, ar putea constitui un pas crucial spre transformarea lor în mini-spioni. Spre deosebire de realizarile de pâna acum, aceasta permite alimentarea atasamentelor pentru o durata lunga de timp, uneori chiar pâna la moartea insectelor.

Daniel Scherson, profesor de chimie la Universitatea Case Western si conducatorul acestei cercetari, spune ca aplicatiile practice sunt nelimitate.

"O insecta dotata cu un senzor ar putea patrunde într-o camera pentru a masura cantitatea de gaz otravitor din aer, ar putea transmite wireless masuratoarea, iar apoi bateria s-ar putea reîncarca de-a lungul unei ore, ca apoi sa reia acest proces de la început", a explicat Scherson.

Cercetatorii încearca acum sa faca bateria cât mai mica, pentru ca insectele sa se poata deplasa si chiar sa zboare, fara a fi incomodate. Calculele oamenilor de stiinta arata ca bateria poate produce 100 de microwati pe centrimetru patrat la 0,2 volti.

Sursa: Daily Mail - via descopera.ro

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MONACO - L’ acquisto di Summify da parte di Twitter è forse la risposta di Jack Dorsey all’ integrazione di Google+ in Google Search da parte di Mountain View, con relativa esclusione di Twitter (e Facebook) dal nuovo motore di social-ricerca. Il co-fondatore di Twitter è stato ospite alla Digital Life Design conference di Monaco, dove ha spiegato che la propria creatura non è (più) un social network, ma uno strumento di informazione.

“Il nostro servizio è incentrato su semplicità e informazione in real time . Vogliamo aiutare l’utente a scoprire cosa sta succedendo ora, mentre negli altri social network - Dorsey dice proprio così -  non hai bisogno di questa immediatezza”. Intervistato sul palco della Dld, Dorsey si toglie un sassolino: “Non siamo focalizzati sul social, come invece Google. Che ha un sacco di evoluzioni da affrontare ancora, con la ricerca che lentamente comincia a essere rimpiazzata dalle applicazioni”.

“Ci stiamo concentrando sulla crescita di Twitter”, ribadisce il presidente della compagnia quando si tratta di spiegare l’acquisizione di Summify, web app e iOS app che crea un sommario degli argomenti più twittati dai nostri contatti. “Vogliamo consegnare ai nostri utenti i contenuti più rilevanti istantaneamente - spiega il co-fondatore di Twitter - e oggi non ci sono più solo twit da 140 caratteri, ma anche foto, video e link ad articoli. Già con l’ultima versione di Twitter abbiamo fatto un passo in questa direzione”. Il destino di Summify, che già pareva segnato, resta dubbio, visto che alla domanda circa eventuali nuove acquisizioni Dorsey risponde: “Siamo sempre in cerca di team in gamba e dato che li possiamo avere acquistando aziende, perché no?”

La sintesi estrema del Dorsey-pensiero è in una frase all’apparenza banale: “Io non controllo più le news, apro Twitter”. Per presentare (l’ex) sito di microblogging come strumento d’informazione il presidente ricorda l’episodio dell’ammaraggio di un aereo nell’Hudson: “La notizia l’ha data su Twitter una persona con venti follower e da lì è arrivata ai media”. Molti, spiega Dorsey, usano Twitter proprio così: per leggere le notizie. Tanto più che “per usare Twitter non è necessario un account”. Visto che “ogni singolo dispositivo sul pianeta è connesso con Twitter” e che “chiunque può partecipare, anche semplicemente mandando un sms”, ecco che ritorna il lato social del sistema, che si configura come un luogo pubblico in cui si trovano le notizie e “dove avvengono conversazioni pubbliche in tempo reale”. Nulla a che fare con Facebook e Google.

L’operazione di ri-posizionamento del prodotto è completata da Dorsey con l’aggiunta di qualche numero (140 milioni di dollari di ricavi nel 2011) e l’assicurazione che il business model basato sui “tweet sponsorizzati”, capaci di coinvolgere gli utenti con una percentuale che varia del 3 al 5%, funziona: “Gli inserzionisti stanno tornando indietro e il fatto che questo abbia un mercato dimostra che la gente è interessata a queste cose”.

(Nella foto: Jack Dorsey al Dld di Monaco. Credit: Johannes Simon/Getty Images)

Fonte: Wired.it - Licenza Creative Commons
This opera is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

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These findings break new ground in the field of biomedicine because they identify an entirely new control mechanism that can be used to induce the formation of complex organs for transplantation or regenerative medicine applications, according to Michael Levin, Ph.D., professor of biology and director of the Center for Regenerative and Developmental Biology at Tufts University’s School of Arts and Sciences.

What’s especially interesting about this is that in research starting in 1937, Dr. Harold S. Burr, Professor Emeritus, Anatomy at Yale University School of Medicine, discovered that abnormal growth (such as cancer) was preceded by the appearance of abnormal voltage gradients in an organ. In a related discovery, Tufts biologists were able to control the incidence of abnormal eyes by manipulating the voltage gradient in the embryo.

The researchers achieved the most surprising results when they manipulated membrane voltage of cells in the tadpole’s back and tail, well outside of where the eyes could normally form. “The hypothesis is that for every structure in the body there is a specific membrane voltage range that drives organogenesis,” said Tufts post-doctoral fellow Vaibhav P. Pai, Ph.D.

Pai noted, “These were cells in regions that were never thought to be able to form eyes. This suggests that cells from anywhere in the body can be driven to form an eye.” To do this, they changed the voltage gradient of cells in the tadpoles’ back and tail to match that of normal eye cells. The eye-specific gradient drove the cells in the back and tail — which would normally develop into other organs — to develop into eyes.

“These results reveal a new regulator of eye formation during development, and suggest novel approaches for the detection and repair of birth defects affecting the visual system,” he said. “Aside from the regenerative medicine applications of this new technique for eyes, this is a first step to cracking the bioelectric code.”

Signals Turn On Eye Genes

From the outset of their research, the Tufts’ biologists wanted to understand how cells use natural electrical signals to communicate in their task of creating and placing body organs. In recent research, Tufts biologist Dany S. Adams showed that bioelectrical signals are necessary for normal face formation in the Xenopus (frog) embryos. In the current set of experiments, the Levin lab identified and marked hyperpolarized (more negatively charged) cell clusters located in the head region of the frog embryo.

They found that these cells expressed genes that are involved in building the eye called Eye Field Transcription Factors (EFTFs). Sectioning of the embryo through the developed eye and analyzing the eye regions under fluorescence microscopy showed that the hyperpolarized cells contributed to development of the lens and retina. The researchers hypothesized that these cells turned on genes that are necessary for building the eye.

Electric Properties of Cells Can Be Manipulated to Generate Specific Organs

The researchers achieved most surprising results when they manipulated membrane voltage of cells in the tadpole’s back and tail, well outside of where the eyes could normally form.

“The hypothesis is that for every structure in the body there is a specific membrane voltage range that drives organogenesis,” said Pai. “By using a specific membrane voltage, we were able to generate normal eyes in regions that were never thought to be able to form eyes. This suggests that cells from anywhere in the body can be driven to form an eye.”

Levin and his colleagues are pursuing further research, additionally targeting the brain, spinal cord, and limbs. The findings, he said “will allow us to have much better control of tissue and organ pattern formation in general. We are developing new applications of molecular bioelectricity in limb regeneration, brain repair, and synthetic biology.”

Changing the Signals Lead to Defects

Changing the bioelectric code, or depolarizing these cells, also affected normal eye formation. They injected the cells with mRNA encoding ion channels, which are a class of gating proteins embedded in the membranes of the cell. Like gates, each ion channel protein selectively allows a charged particle to pass in and out of the cell.

Using individual ion channels, the researchers changed the membrane potential of these cells. This affected expression of EFTF genes, causing abnormalities to occur: Tadpoles from these experiments were normal except that they had deformed or no eyes at all.

Further, the Tufts biologists were also able to show that they could control the incidence of abnormal eyes by manipulating the voltage gradient in the embryo. “Abnormalities were proportional to the extent of disruptive depolarization,” said Pai. “We developed techniques to raise or lower voltage potential to control gene expression.”

Source: Kurzweil Accelerating Intelligence via ZeitNews.org

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"Avem în prezent 12 cazuri de persoane infestate, dintre care 3 au decedat deja", declara Zarir Uwadia, conducatorul echipei de medici din cadrul Hinduja National Hospital and Medical Research Center din Mumbai, care a descoperit noua tulpina de tuberculoza.

Pe lânga faptul ca noua tuberculoza nu poate fi tratata, exista riscul pierderii controlului raspândirii bolii în cadrul unei populatii umane extrem de dense si aglomerate cum este cea din India.

În India a apărut tuberculoza rezistentă la orice fel de antibiotice

Organizatia Mondiala a Sanatatii a convocat urgent o întâlnire la cel mai înalt nivel, pentru a decide cele mai eficiente masuri de contracarare a unei posibile epidemii cu repercusiuni greu de anticipat.

Tuberculoza rezistenta la medicatie, sau Multidrug-resistant tuberculosis (MDR-TB), care este rezistenta la tratamentul pe baza de isoniazida si rifampina, a aparut pentru prima data în anul 2006.

În prezent, atentia lumii medicale internationale este îndreptata asupra tuberculozei total-rezistenta (TDR-Tuberculosis). Primele cazuri au fost înregistrate în anul 2007 în Italia, apoi, în anul 2009, au mai fost descoperite 15 cazuri de infestare în Iran.

Daca în cazul infestarii cu tuberculoza obisnuita costurile tratamentului sunt de doar 20$, iar în cazurile de MDTR-TB costurile sunt între 2.000-12.000$, ultima tulpina de tuberculoza nu poate fi tratata cu niciun fel de medicamente.

Sursa: New Scientist - via descopera.ro

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Cercetatorii din cadrul Universitatii Yamazaki Gakuen din Tokyo au descoperit ca talpile si degetele câinilor sunt prevazute cu o retea de glande care elimina o secretie foarte bogata în grasimi, care împiedica degerarea.

De ce căţeilor nu le îngheaţă picioarele?

Daca oamenii sunt expusi la temperaturi foarte scazute, vasoconstrictia vaselor de sânge din extremitatile corpului duce la reducerea fluxului sangvin din acele zone.

Echipa de cercetatori condusa de dr. Hiroyoshi Ninomya s-a folosit de un scaner atasat unui microscop electronic pentru a studia labele a 4 câini maturi. Oamenii de stiinta au descoperit astfel ca arterele care trimit sângele spre picioarele câinilor sunt cuplate cu o retea de vene mici, întregul sistem actionând ca un schimbator de caldura., având rolul de a încalzi sângele rece provenit din zona talpilor înainte de a-l trimite înapoi în restul corpului.

Acest tip de adaptare extrema a fost identificat la vulpile polare, precum si în picioarele pingunilor si înotatoarele delfinilor. Descoperirea sugereaza ca specia câinilor ar fi originara din regiunile reci, unde o astfel de adaptare ar fi fost esentiala pentru supravietuire.

Sursa: Physorg.com - via descopera.ro

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Monopolio Siae abolito, anzi no. I minuti successivi alla conferenza stampa di presentazione del decreto liberalizzazioni del governo di Mario Monti hanno fatto (ben) sperare in merito a un rivoluzionario cambiamento della gestione dei diritti d'autore, tradizionalmente nelle esclusive (quantomeno entro i confini nazionali) mani della Società Italiana degli Autori ed Editori. Ulteriori verifiche e analisi di quanto previsto dal comma 2 dell'articolo 39 del decreto, che ricordiamo deve ancora passare al vaglio del Parlamento, hanno permesso di dare una chiave di lettura più precisa.

A venire toccati " al fine di favorire la creazione di nuove imprese nel settore della tutela dei diritti degli artisti interpreti ed esecutori" sono " i diritti connessi al diritto d'autore", la cui " attività di amministrazione e intermediazione" diventa " libera". Monti & Co. sono quindi intervenuti nel campo d'azione del Nuovo IMAIE, che si occupa appunto della riscossione e tutela dei diritti spettanti - ad esempio - ad artisti che effettuano registrazioni o legati all'immagine dei titolari delle opere, e hanno imposto la concorrenza all'interno dello stesso. Si tratta, come spiega a Wired.it il segretario di Agorà Digitale Luca Nicotra, comunque " di un successo enorme, che apre ad altre modifiche del settore: se passa l'idea che una competizione tra enti commerciali o cooperative di autori è vantaggiosa e utile ulteriori aperture sono possibili". Il capitolo IMAIE, aggiunge Nicotra, " era intoccabile" alla stessa stregua di quello Siae, non a caso il commissario straordinario Gian Luigi Rondi ha sentito il bisogno di ribadire l'importanza del ruolo della Società Autori ed Editori nel giorno dell'approvazione da parte del Cdm del decreto.

In Parlamento, aggiunge l'avvocato Guido Scorza, sono già presenti 6 o 7 disegni di legge atti ad abolire il famoso articolo 180 della legge 633 del 1941, che tiene da anni sotto scacco chiunque voglia accedere a materiale con il bollino Siae. Scorza cita, per rendersi conto degli effetti di una gestione monopolistica del settore, lo studio dell'istituto Bruno Leoni, secondo il quale fatto 7 il costo di una serata musicale in termini di diritti in Italia, in Inghilterra bisogna sborsare solo 1. La medesima analisi evidenzia come l'attuale regolamentazione costi ai soggetti coinvolti (autori, discografici e fruitori) 13,5 milioni di euro all'anno.

Fonte: Wired.it

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But in second place, at over 17 billion tons consumed each year, comes concrete made with Portland cement. Portland cement provides the essential binder for strong, versatile concrete; its basic materials are found in many places around the globe; and, at about $100 a ton, it's relatively cheap. Making it, however, releases massive amounts of carbon dioxide, accounting for more than five percent of the total CO2 emissions from human activity.

"Portland cement is the most important building material in the world," says Paulo Monteiro, a professor of civil and environmental engineering at the University of California at Berkeley, "but if we are going to find ways to use it more efficiently – or just as important, search for practical alternatives – we need a full understanding of its structure on the nanoscale." To this end Monteiro has teamed with researchers at the U.S. Department of Energy's Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory.

In nanoscale studies of calcium-silicate-hydrate, a binder critical to the strength and durability of Portland cement, the mineral tobermorite is a perfect stand-in for determining the crystal structure of this extraordinarily complex material. Highly structured layers of calcium and oxygen atoms alternate with "interlayers" of silicon, oxygen, calcium, and water molecules, where disorder may occur and adversely affect the material's properties.

Most recently, at ALS beamline 12.2.2, Monteiro and his colleagues gradually squeezed specks of fine dust of the mineral tobermorite between faces of two diamonds in a diamond anvil cell, until they achieved pressures like those 100 miles below the surface of Earth. This was the first experiment to determine tobermorite's bulk modulus – its "stiffness" – from diffraction patterns obtained by sending a bright beam of x rays through the sample, revealing how its structure changed as the pressure increased.

The results, which will appear in Cement and Concrete Research and are now available online to subscribers, led to new insights into calcium-silicate-hydrate (C S H), the material primarily responsible for the strength and durability of concrete made with Portland cement.

Cement on the nanoscale

Portland cement is made by baking limestone (calcium carbonate) and clay (silicates) in a kiln at over 1400 degrees Celsius to make "clinker," which is then ground to a powder. When the powder is mixed with water, calcium-silicate-hydrate (C-S-H) is formed, which, although poorly crystallized, is a binder critical to the strength and durability of the cement paste.

"We and many other groups have developed sophisticated computer models to understand the crystal structure and mechanical behavior of C S H, based on observations of how it performs," says Monteiro. "But we're the only group that uses minerals to validate the results of our models with experimental results."

Despite the many studies and vast literature on cements and their components, the atomic scale structure of C-S-H, owing to its high complexity, is still imperfectly known. While the mineral tobermorite, a calcium silicate hydrate named for a quaint village on the Scottish Isle of Mull, is far less common than the makings of Portland cement, one of its structures, designated 14Ĺ tobermorite, is a perfect stand in for C-S-H in nanoscale studies.

The studies were performed at beamline 12.2.2, the California High-Pressure Science Observatory (Calipso), which is supported by the National Science Foundation. Calipso is equipped with a choice of diamond anvil cells, arranged so the x-ray beam passes through the diamonds and the sample chamber between them. The diffracted x-rays fall on a CCD detector, and the diffraction patterns can be used to determine the structure of the material in the cells.

The tiny sample of tobermorite that Monteiro's team used at the ALS originally came from Southern California and was obtained from the Los Angeles County Museum. The researchers ground it to a fine powder and suspended it in liquid so that the diamond anvil cell would apply even hydrostatic pressure to every grain in the sample chamber – an opening in a metal gasket only 180 millionths of a meter in diameter.

"While it's possible to do x-ray diffraction with diamond anvil cells on a laboratory bench," says ALS beamline scientist Simon Clark, a co-author of the research, "you can't deal with samples this small without the brightness of a synchrotron light source. Even if you could, what takes eight hours in the lab we can do in half a minute – although we usually take at least a minute so the researchers can write everything down in their notebooks."

Putting on the squeeze

As the experiments proceeded, the flattened points of the cell's two diamonds were slowly tightened, concentrating pressure on the gasket and the contents of the sample chamber. The x-ray diffraction patterns revealed any changes in the arrangement of atoms in the crystal structure.

Says Monteiro, "The diffraction patterns give us the lattice parameters of the tobermorite structure." Lattice parameters allow the volume of the unit cells, the material's fundamental atomic arrangements, to be calculated in three directions. "We watch how the lattice parameters change as the pressure changes, using them as a strain gauge. By knowing the applied pressure in the anvil cell, we can compute the bulk modulus."

At Calipso, the California High-Pressure Science Observatory at beamline 12.2.2 of the Advanced Light Source, materials can be squeezed to tremendous pressures in diamond anvil cells, where they are trapped between the two diamonds in a small central chamber. The X-rays from the beamline pass through the diamonds and the sample, throwing diffraction patterns on a CCD detector that reveal the material’s structure. (Signals from diamond and corundum in the anvil cell mechanism must be subtracted from the diffraction patterns.) Credit: Beamline photo by Roy Kaltschmidt, Lawrence Berkeley National Laboratory

In C-S-H the calcium, silicon, and oxygen atoms are arranged in a stack of flat layers. Highly structured layers of calcium and oxygen atoms alternate with "interlayers" of silicon, oxygen, calcium, and water molecules. In the plane of the layers (the a and b directions of the lattice parameters), tobermorite is very stiff indeed, changing very little as pressure increases. Perpendicular to the plane, along the c-axis, tobermorite is more compressible, but not by much.

Even in the c direction, pure tobermorite is stiffer than a synthetic version of C-S-H the Monteiro team also tested, and to which they compared it. The calcium-oxygen layers in the synthetic C-S-H were similar to those in the tobermorite, so when altered silicon chains were deliberately introduced into the synthetic in order to mimic the disorder of natural C S H, it still retained its stiffness in the a-b plane. But along the c-axis, the disordered synthetic C-S-H grew significantly more squeezable.

"It's the interlayers that compress, and only along the c-axis," says Monteiro. "Differences in interlayer spacing, degrees of disorder in the silicon chains, additional calcium ions, and water molecules all make the bulk modulus of the two materials virtually the same in the a-b plane, but different along the c axis. The discovery suggests a number of possibilities for improving the performance of cement – for example, one might introduce special polymers into the C-S-H interlayers to shape its behavior. This will certainly be an area for our future research."

Source: Lawrence Berkeley National Laboratory via ZeitNews.org

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În ciuda acestei vesti bune, specialistii spun ca fenomenul nu va fi de lunga durata daca încalzirea globala va continua si daca viteza vântului va înregistra fluctuatii în urmatorul deceniu.

Studiul s-a bazat pe analizarea datelor, adunate de-a lungul a 4 decenii, ale unei populatii de albatrosi din insulele Crozet. Colectarea datelor a început în 1966, dar abia în 1989 albatrosii au fost dotati cu transmitatoare ale caror semnale au putut fi înregistrate prin satelit.

Albatroşii prosperă datorită curenţilor de aer

De-a lungul timpului, specialistii au observat ca o crestere a presiunii atmosferice, provocata probabil de încalzirea globala, a facut ca viteza vântului sa sporeasca în vestul Oceanului Indian, zona pe care albatrosii o strabat cel mai des.

Ca urmare a acestei schimbari din mediu, albatrosii zboara mai repede, parcurgând distante mai mari spre sud, iau mai mult în greutate, petrec mai putin timp cautând hrana si au mai multi pui.

Vântul puternic le permite sa zboare pe suprafete mai mari si sa gaseasca hrana mult mai repede. Astfel, o femela poate ajunge sa cântareasca 8 kilograme, iar un mascul 10.

Cresterea în greutate se poate datora usurintei cu care gasesc hrana, dar specialistii spun ca poate fi vorba si de o adaptare a pasarilor pentru a maximiza capacitatea de a zbura pe distante lungi.

Cu toate acestea, daca fenomenul va continua sa ia amploare, pâna în 2080, viteza vântului va fi atât de mare, încât albatrosii nu vor mai putea sa ajunga pe insulele Crozet.

Sursa: AFP - via descopera.ro

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Non più braccia rubate all'agricoltura. Beh, quasi. Per rivalutare i terreni, richiamare i giovani da zone di emigrazione e non disperdere la coltivazione secolare degli ulivi, gli abitanti di Rasquera, hanno deciso di affittare alcuni appezzamenti di terreno per la coltivazione della cannabis il cui consumo personale, in Spagna è considerato legale.

In tempo di crisi ogni soluzione può essere buona per fare cassa o alimentare un sistema economico in difficoltà. La novità, se così si può chiamare, arriva dalla Spagna, per la precisione a Rasquera, neanche 900 abitanti nella provincia di Terragona, dove il Consiglio Comunale ha deciso la destinazione di alcuni terreni. Tutto normale se non fosse che la coltivazione decisa è quella di marijuana, con un ritorno previsto di 1,336 milioni di euro in due anni.

La volontà della giunta di sinistra sarebbe quella di fronteggiare la crisi (e in questo ci sono roiusciti visto che almeno quaranta persone avranno da lavorare) affiancando alla produzione di ulivi, quella di piante alternative. In tutti i sensi.

Con un debito di 1,3 milioni di euro non bisogna andare troppo per il sottile e allora ci si risolve ad accettare l'offerta di nuovi partner. In questo caso quella arrivata dall' Asociacion Barcelonesa Cannabica de Autoconsumo (Abcda), un club «con fini ludico-terapeutici» con 5mila soci, creato per gestire il consumo individuale di cannabis che, in Spagna è consentito.

In cifre la Abcda offrirebbe al comune 36 mila euro per l'autorizzazione alla coltivazione non lucrativa della pianta e 550 mila euro annui per la gestione dei terreni. Per la serie: fare di necessità virtù.

Fonte: trend-online.com - Autore: ROSSANA PREZIOSO

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