Immagine
 Trilingual World Observatory: italiano, english, română. GLOBAL NEWS & more... di Redazione
   
 
Di seguito tutti gli interventi pubblicati sul sito, in ordine cronologico.
 
 
By Admin (from 01/08/2011 @ 14:00:11, in ro - Stiinta si Societate, read 1152 times)

 Nu are in ea nimic neveridic, nimic mistic, acea fraza biblica intrata in mentalul comun, care ne spune ca „din pamant am fost facuti si-n pamant ne vom intoarce”. De fapt, este vorba despre stiinta pura, asezata in tipare filosofice crestine: corpul material al omului e alcatuit din elemente chimice regasite si in natura, iar dupa moarte el se descompune in aceleasi elemente, amestecandu-se la modul cel mai concret cu componentele similare ale taranii. O tulburatoare ipoteza a astrofizicienilor adauga insa un plus de „taina” acestei alcatuiri, plasandu-se intre parametri cosmici, intr-o maniera absolut originala si impresionanta.

Pulbere de stele

Aceasta frumoasa metafora ne-a fost oferita tot de oamenii de stiinta, pe baza constatarii ca stelele sunt cele ce fabrica pretiosul „praf” din care suntem noi insine facuti. Nu orice fel de praf, totusi: intre altele, el contine carbon, oxigen, calciu, magneziu si alte elemente aflate la originea atomilor care alcatuiesc oasele, muschii, pielea, dar si trandafirul, leul, ornitorincul; adica tot ce este viu.

Acest praf stelar, „vagabondand” prin Univers, a fost integrat candva in planeta noastra aflata in curs de formare, apoi a trecut in toate organismele terestre. Numai ca, recent, o „bomba” stiintifica a fost dezamorsata de o echipa de cercetatori ai universitatii din Manchester. Potrivit acestora, stramosii nostri de la inceputuri nu ar fi doar stelele, ci si cei mai cumpliti „pradatori” din Univers cunoscuti pana acum: gaurile negre.

Intuneric si lumina

Totul a inceput prin studierea unui quasar (o galaxie foarte tanara, in centrul careia se afla o gaura vorace, hiperactiva, inconjurata de un imens nor de gaze. Aspirat de gaura neagra, acesta dispare emitand o cantitate de energie fabuloasa, care incalzeste praful cosmic din jur. Totusi, chiar se poate afirma ca la originea acestui praf se afla gaura neagra?

La modul general, ea e prezentata ca un aspirator gigantic: avand o masa colosala (cam de un miliard de ori mai mare decat cea a Soarelui nostru), exercita o atractie gravitationala pe masura, absorbind tot ce ajunge in preajma lor. Nimic nu scapa, nici macar lumina! Insa, in ciuda „lacomiei” sale devoratoare, din cand in cand elimina materie, sub forma de jeturi de particule foarte puternice. Este vorba despre asa-numitul vant de quasar, in compozitia caruia s-ar putea regasi praful generator de viata terestra.

Dizolvarea timpului

Mecanismul nu e cunoscut in detalii, dar se crede ca vanturile de quasari provoaca unde de soc capabile sa comprime gazul, iar atomii se reunesc, formand amintitul praf ce intra in structura noastra intima. Fenomenul a fost atribuit mai intai unor quasari aflati la circa 13 miliarde ani-lumina distanta de noi. Universul ar avea insa varsta de sub un miliard de ani, fapt ce i-a indreptat pe cercetatori catre galaxii mai tinere.

Astfel, ei afirma ca au depistat in vecinatatea gaurilor negre prezenta forsteritei, un mineral ce nu apare in praful galaxiilor batrane si care are nevoie sa fie fabricat permanent, pentru a supravietui, operatiune aflata „la indemana” vanturilor de quasari. Fireste ca ipoteza engleza se loveste de altele, bazate pe originea stelara a prafului vietii. Poate ca, de fapt, ambele sunt valabile. Cert este ca va trebui sa se mai studieze si alti quasari, pentru a se afla daca omul e alcatuit din intunericul si lumina Universului; asadar, daca putem spune ca suntem copii ai stelelor, dar si ai gaurilor negre.

ADRIAN-NICOLAE POPESCU - magazin.ro

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 

A dimostrarlo, applicando allo studio dei fossili tecniche di tomografia computerizzata, è stato un gruppo di ricercatori statunitensi della University of Texas - Austin, del Carnegie Museum of Natural History (Pittsburgh) e della St. Mary's University (San Antonio), il cui lavoro è apparso nella rivista Science.

Detail-premammiferi-cervello-olfatto

Per la prima volta, i paleontologi statunitensi sono riusciti a scannerizzare crani fossili di due mammiferi ancestrali - il morganucodonte e l'adrocodio - così da ricrearne dei modelli interni. “Questi due animali – spiegano gli studiosi – popolavano la Cina durante il Giurassico Inferiore, tra 199 milioni e 175 milioni di anni fa”. Entrambi di piccole dimensioni (soprattutto l'adrocodio, lungo più o meno come una graffetta), sono considerati tra i primi cugini ancestrali dei mammiferi odierni per via della loro capacità cranica, di gran lunga superiore rispetto a quella dei loro contemporanei.

Il gruppo di ricerca, guidato da Tim Rowe, direttore del Laboratorio di Paleontologia dei Vertebrati dell'Università del Texas, ha trascorso diversi anni a scannerizzare più di una dozzina di crani fossili di pre-mammiferi con una tecnica chiamata tomografia computerizzata (CT) a raggi X, di solito utilizzata in ambito medico. “La tecnologia CT è indispensabile per l'analisi di fossili così fragili, poiché consente di ricreare immagini precise e tridimensionali di una cavità cranica fossilizzata senza il rischio di danneggiare il reperto”, precisano gli studiosi. Le immagini, ottenute presso la High-Resolution X-ray Computed Tomography Facility di Austin, sono state archiviate online e possono essere consultate al sito http://www.digimorph.org/.

Questi modelli tridimensionali hanno permesso ai ricercatori di osservare dall'interno il cervello e le cavità nasali di questi fossili e riscontrare un allargamento della cavità nasale e delle regioni legate all'olfatto, così come delle aree del cervello deputate a processare le informazioni olfattive. “Entrambe le caratteristiche – spiegano nell'articolo – indicano un miglioramento della capacità olfattiva nei pre-mammiferi”.

Lo studio, tuttavia, non si limita a esplorare il ruolo dell'olfatto nell'evoluzione cerebrale dei mammiferi, ma cerca anche di ricostruirne una storia “a puntate”. Secondo Rowe e colleghi, infatti, il cervello dei mammiferi si sarebbe evoluto in almeno tre fasi, di cui il miglioramento del senso dell'olfatto non è che la prima e la più significativa. Gli altri due momenti di sviluppo, spiegano i ricercatori, sarebbero correlati all'aumento della sensibilità tattile dovuta ai peli corporei e al miglioramento della coordinazione neuromuscolare o dell'abilità di produrre movimenti muscolari più precisi utilizzando i sensi.

Gli autori, infatti, ipotizzano che il pelo (di cui erano dotati sia l'adrocodio che il morganucodonte) servisse originariamente a “guidare” gli animali e ad aiutarli a muoversi all'interno di piccole fessure senza farsi del male. Questa accentuata sensibilità tattile avrebbe favorito la formazione di intricati campi sensoriali nella neocorteccia del cervello mammifero. Infine, poiché la neocorteccia è coinvolta sia nella percezione sensoriale sia nella produzione dei comandi del movimento, il suo sviluppo avrebbe contribuito alla messa a punto delle capacità motorie e della coordinazione neuromuscolare dei pre-mammiferi.

“Grazie a questo studio disponiamo ora di un quadro generale del cervello mammifero ancestrale”, precisano i ricercatori. “Ora siamo in grado di elaborare ipotesi più dettagliate sulla sequenza di eventi che ha portato all'evoluzione cerebrale dei mammiferi e sull'importanza dei diversi sistemi sensoriali”. “Prossimamente – ha concluso Rowe – esploreremo la successiva diversificazione del cervello e dei sistemi sensoriali. Questo ci permetterà di scoprire nuovi segreti su come abbiano fatto i mammiferi a sviluppare cervelli molto grandi e capacità sensoriali estremamente specifiche, come ad esempio l'elettrorecezione negli ornitorinchi e i sonar biologici di balene e pipistrelli”.

Fonte: GalileoNet.it - Riferimenti: Science DOI: 10.1126/science.1206915 - Credits: Mark A. Klingler/Carnegie Museum of Natural History

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 

The advance, featured this week in the early online edition of the journal Proceedings of the National Academy of Sciences, represents the first demonstration of lens-free optical tomographic imaging on a chip, a technique capable of producing high-resolution 3-D images of large volumes of microscopic objects.

Optical microscope without lenses produces high-resolution 3-D images on a chip

"This research clearly shows the potential of lens-free computational microscopy," said Aydogan Ozcan, senior author of the research and an associate professor of electrical engineering at UCLA's Henry Samueli School of Engineering and Applied Science. "Wonderful progress has been made in recent years to miniaturize life-sciences tools with microfluidic and lab-on-a-chip technologies, but until now optical microscopy has not kept pace with the miniaturization trend."

An optical imaging system small enough to fit onto an opto-electronic chip provides a variety of benefits. Because of the automation involved in on-chip systems, scientific work could be sped up significantly, which might have a great impact in the fields of cell and developmental biology. In addition, the small size not only has great potential for miniaturizing systems but also leads to cost savings on equipment.

The optical microscope, invented more than 400 years ago, has tended to grow larger and more complex as it has been modified to image ever-smaller objects with better resolution. To address this lack of progress in miniaturization, Ozcan's research group — with graduate student Serhan Isikman and postdoctoral scholar Waheb Bishara as lead researchers — developed the new tomographic microscopy platform through the next evolution of a lens-free imaging technology the group created and has been improving for years.

Ozcan, a researcher at the California NanoSystems Institute at UCLA, makes the analogy that a traditional optical microscope is like a huge set of pipes delivering content, in the form of images, to the user. Over years of development, bottlenecks occur that impede further improvement. Even if one part of the system — that is, one bottleneck — is improved, other bottlenecks keep that improvement from being fully realized. Not so with the lens-free system, according to Ozcan.


"Lens-free imaging removes the pipes altogether by utilizing an entirely new design," he said.

The system takes advantage of the fact that organic structures, such as cells, are partially transparent. So by shining a light on a sample of cells, the shadows created reveal not only the cells' outlines but details about their sub-cellular structures as well.

"These details can be captured and analyzed if the shadow is directed onto a digital sensor array," Isikman said. "The end result of this process is an image taken without using a lens."

Ozcan envisions this lens-free imaging system as one component in a lab-on-a-chip platform. It could potentially fit beneath a microfluidic chip, a tool for the precise control and manipulation of sub-millimeter biological samples and fluids, and the two tools would operate in tandem, with the microfluidic chip depositing and subsequently removing a sample from the lens-free imager in an automated, or high-throughput, process.

The platform's 3-D images are created by rotating the light source to illuminate the samples from multiple angles. These multiple angles also allow the system to utilize tomography, a powerful imaging technique. Through the use of tomography, the system is able to produce 3-D images without sacrificing resolution.

"The field of view of lens-based microscopes is limited because the lens focuses on a narrow area of a sample," Bishara said. "A lens-free microscope has both a much larger field of view and depth of field because the imaging is done by the digital sensor array and is not constrained by a lens."

Source: PhysOrg

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 
By Admin (from 31/07/2011 @ 14:00:33, in ro - Stiinta si Societate, read 1631 times)

 Daca pentru multi dintre noi fericirea este doar o notiune fara corespondent in viata reala, budistii o considera un deziderat la care se poate ajunge prin meditatii intense. De altfel, multi intelepti apartinand acestei religii cu milioane de adepti in intreaga lume, sustin ca ar fi gasit fericirea in starile de extaz mistic, obtinute prin meditatie. Oamenii de stiinta au stabilit de altfel ca prin antrenamente intense, budistii reusesc stimularea permanenta a regiunii cerebrale situate in lobul prefrontal stang si  asociate, de obicei, cu emotiile pozitive si starea de „bine”, resimtita uneori de oricare dintre noi, astfel incat viata lor devine un lung sir de momente de extaz si fericire.  Din acest punct de vedere, „campion absolut” la fericire se poate considera francezul Matthieu Ricard, ce traieste de o buna bucata de timp intr-un permanent extaz...

Fuga de „civilizatie”

 Matthieu Ricard a vazut lumina zilei in anul 1946, la Paris, intr-o Franta devastata de razboi si macinata de conflicte fratricide. Tatal sau, filosoful, eseistul si ziaristul Jean-Francois Ricard a adoptat ulterior ca nume pseudonimul sub care fusese cunoscut in miscarea de Rezistenta, Revel, devenind celebru astfel; mama lui Matthieu, pictorita Yahne Le Toumelin, i-a insuflat inca de mic dragostea de frumos, in vreme ce parintele sau l-a invatat sa iubeasca intelepciunea.

In plina perioada „flower-power”, cu un an inainte ca Franta sa fie cuprinsa de o furtunoasa revolta a studentimii impotriva politicianismului burghez, tanarul de 21 de ani pleaca in India, pentru a cunoaste stilul de viata si credintele oamenilor de aici. Revine apoi la Paris si isi da teza de doctorat in genetica moleculara, sub indrumarea faimosului profesor Francois Jacob, laureat al Premiului Nobel pentru Medicina si este angajat apoi la Institutul Pasteur. Se parea ca genialul tanar era destinat unei stralucite cariere in domeniul cercetarii dar spre surprinderea tuturor, inclusiv a familiei sale, in 1972, Matthieu abandoneaza civilizatia spre a se retrage intr-o manastire din muntii Himalaya. De atunci, practica asiduu budismul, peregrinand prin mai multe manastiri apartinand acestei religii si stabilindu-se, in momentul de fata, la Shenchen, in Nepal.

Traind printre Iluminati

De-a lungul anilor, pe langa preocuparile sale religioase, Matthieu Ricard a ramas atras de arta, in special de fotografie. Imaginile surprinse de el reprezinta o veritabila cronica pictata a frumusetilor Tibetului, a manastirilor, calugarilor si maestrilor spirituali de aici. Ricard i-a cunoscut practic pe toti iluminatii budisti, oameni care au trait o viata intreaga in manastire, departe de lume, si care au capatat astfel fabuloase puteri ale spiritului. De altfel, mentorul sau a fost Dilgo Khyentse Rinpoche, considerat cel mai mare initiat budist al secolului trecut, care a murit in anul 1991.

Dupa anul 2000, Ricard s-a implicat activ in infiintarea Institutului pentru Minte si Viata, care are ca scop „impacarea” stiintei si religiei, pe baze logice. Totodata, a participat activ la studiile vizand antrenamentul creierului pentru atingerea starilor de extaz (un exemplu de plasticitate neuronala), studii desfasurate intre 2001 si 2003 la universitatile americane Madison-Wisconsin, Princeton si Berkeley. Absolut toti banii proveniti din drepturile sale de autor au fost donati de Matthieu pentru construirea de clinici, scoli, orfelinate in Nepal si India. Pentru activitatile sale umanitare, calugarul-savant a primit Ordinul National de Merit al Republicii Franceze.

„Este cu siguranta un fenomen”

In urma cu cativa ani, Matthieu Ricard s-a lasat testat de savantii americani, scanarea creierului sau cu ajutorul unui computer tomograf lasandu-i perplecsi pe acestia. Astfel, ei au depistat o activitate neobisnuit de intensa in cortexul pre-frontal al creierului lui Ricard, nivelele acestei activitati fiind neatinse de nici o alta fiinta umana! Rezultatul analizei i-a atras, cum era si firesc, supranumele de „cel mai fericit om din lume”. „Este cu siguranta un fenomen si din pacate, chiar daca avem aceste rezultate uluitoare, nu stim inca sa le interpretam. Tot ceea ce putem face este sa reflectam la uimitoarele puteri ale creierului uman”, spune Antoine Lutz, savantul care l-a studiat pe Ricard in iunie 2002, pozitionandu-i pe cap nu mai putin de 128 de electrozi.

Lutz i-a cerut calugarului budist sa mediteze la „iubirea neconditionata si la compasiunea fata de semeni” si imediat a observat o puternica activitate in sfera undelor cerebrale gamma, de circa 40 cicli pe secunda, indicand o gandire intensa. Dar savantii au ramas stupefiati de cele observate, intrucat de obicei undele gama sunt foarte slabe si dificil de observat, in timp ce acelea emanate de creierul lui Ricard erau vizibile chiar si pe o banala electroencefalograma! Mai mult, oscilatiile intre diverse parti ale cortexului erau sincronizate – fenomen remarcat doar la pacientii aflati sub anestezie – semn ca initiatul de origine franceza isi putea controla singur centrii durerii.

Crezand ca instrumentele lor ar putea fi defecte, oamenii de stiinta au repetat experimentul pe cinci calugari budisti si pe cinci studenti. S-a observat ca undele gama produse de calugari erau de 30 de ori mai puternice decat cele emise de creierele studentilor, dar nu se puteau compara totusi cu cele produse de creierul lui Matthieu Ricard. A fost o demonstratie practica venind in sprijinul cuvintelor calugarului budist, care spunea, inca din 1989: „Mintea este un instrument minunat, ea poate fi antrenata asemenea unor muschi sa se dezvolte, iar meditatia este cea care guverneaza acest antrenament. In toti acesti ani de cand practic meditatia am observat ca mintea este foarte maleabila. Vietile noastre se pot transforma miraculos fie si daca ne schimbam doar putin modul de a gandi, percepe si interpreta lumea. Fericirea este o calitate care poate fi dobandita prin munca si rabdare”.

GABRIEL TUDOR - magazin.ro

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 

Il progetto che ci vede coinvolti in prima fila si chiama Thebera ed è stato presentato lo scorso 17 maggio a Milano. Perché l’Egitto e perché l’Italia? Il primo detiene il triste primato mondiale di diffusione di epatite C (causa del 40% circa di tutti i trapianti di fegato), mentre noi abbiamo una delle reti trapiantologiche migliori d’Europa, oltre alle competenze e l’esperienza che mancano ai medici nordafricani.
Lo scorso giugno è stata varata la prima direttiva europea in ambito trapiantologico che esorta alla cooperazione internazionale per la diffusione delle competenze medico-scientifiche nel bacino del Mediterraneo. E Thebera è il primo programma con cui si passa dalle parole ai fatti, con l’Italia a fare da apripista. Il progetto, finanziato con 1.200.000 euro (600.000 a partner) dal VII Programma Quadro, è partito nel novembre 2010 e durerà due anni. “Durante questo periodo verranno formati gruppi da 20 operatori ciascuno - già selezionati – che partiranno dal Theodor Bilharz Research Institute, a Giza, alla volta dell’Italia; qui saranno accolti nelle unità trapiantologiche di vari ospedali”, spiega Franco Filippini direttore del Dipartimento di trapiantologia epatica, epatologia dell'Azienda Ospedaliero Universitaria Pisana, e presidente del Sisqt (Società per la sicurezza e qualità dei trapianti). Pisa è infatti capofila ma, oltre la Toscana, sono coinvolte altre regioni, tra cui Emilia Romagna, Lazio, Campania, Veneto, Marche e Piemonte.

Detail-europa_2020

Nella seconda fase del progetto, invece, saranno i medici italiani ad andare in Egitto, per continuare la formazione. Le équipe multidisciplinari dovranno essere preparate su tutti gli aspetti delle malattie epatiche, dal loro riconoscimento fino al trapianto del fegato: saranno quindi coinvolte diverse figure professionali, dai radiologi agli epidemiologi ai chirurghi, e verranno fornite le strumentazioni necessarie per la diagnosi. “È un progetto innovativo e pilota – sottolinea Alessandro Stefani, del consiglio scientifico del progetto – e si sta anche testando la tipologia di approccio a questi paesi”.

Ma perché l’Eu si preoccupa del Nord Africa? “La nuova politica europea non vuole più soltanto esportare i modelli di eccellenza, ma condividerli e integrare i paesi del Mediterraneo – risponde Stefani – e creare reti”. Inoltre si tratta di fare prevenzione, anche economica: “Il problema in Egitto è grave e investe la sfera sociale. Queste persone verranno a curarsi anche da noi. Invece di aspettare, possiamo pensarci prima, fare prevenzione, aiutarli a sondare la gravità della malattia epatica e a curarsi”, continua Stefani.

L’Italia non solo è il paese ideale per il know-how e le somiglianze con l'Egitto (eseguiamo circa mille trapianti di fegato l’anno e abbiamo un tasso di diffusione del virus dell’epatite C molto elevato), ma anche per la vicinanza geografica: siamo la porta dell’Unione verso il Nord Africa, in vista di altri progetti di cooperazione internazionale nell’ambito delle politiche sanitarie della strategia Europa 2020. In questi due anni dovremo fornire la prova dell’importanza e della validità di tali programmi.

Fonte: galileonet.it

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 

Viewers, for instance, can use the system to focus in on the details of a booth within a panorama of a carnival midway, but also reverse time to see how the booth was constructed. Or they can watch a group of plants sprout, grow and flower, shifting perspective to watch some plants move wildly as they grow while others get eaten by caterpillars. Or, they can view a computer simulation of the early universe, watching as gravity works across 600 million light-years to condense matter into filaments and finally into stars that can be seen by zooming in for a close up.

"With GigaPan Time Machine, you can simultaneously explore space and time at extremely high resolutions," said Illah Nourbakhsh, associate professor of robotics and head of the CREATE Lab. "Science has always been about narrowing your point of view — selecting a particular experiment or observation that you think might provide insight. But this system enables what we call exhaustive science, capturing huge amounts of data that can then be explored in amazing ways."

The system is an extension of the GigaPan technology developed by the CREATE Lab and NASA, which can capture a mosaic of hundreds or thousands of digital pictures and stitch those frames into a panorama that be interactively explored via computer. To extend GigaPan into the time dimension, image mosaics are repeatedly captured at set intervals, and then stitched across both space and time to create a video in which each frame can be hundreds of millions, or even billions of pixels.

An enabling technology for time-lapse GigaPans is a feature of the HTML5 language that has been incorporated into such browsers as Google's Chrome and Apple's Safari. HTML5, the latest revision of the HyperText Markup Language (HTML) standard that is at the core of the Internet, makes browsers capable of presenting video content without use of plug-ins such as Adobe Flash or Quicktime.

Using HTML5, CREATE Lab computer scientists Randy Sargent, Chris Bartley and Paul Dille developed algorithms and software architecture that make it possible to shift seamlessly from one video portion to another as viewers zoom in and out of Time Machine imagery. To keep bandwidth manageable, the GigaPan site streams only those video fragments that pertain to the segment and/or time frame being viewed.

"We were crashing the browsers early on," Sargent recalled. "We're really pushing the browser technology to the limits."

Guidelines on how individuals can capture time-lapse images using GigaPan cameras are included on the site created for hosting the new imagery's large data files, http://timemachine.gigapan.org/wiki/Main_Page . Sargent explained the CREATE Lab is eager to work with people who want to capture Time Machine imagery with GigaPan, or use the visualization technology for other applications.

Once a Time Machine GigaPan has been created, viewers can annotate and save their explorations of it in the form of video "Time Warps."

Though the time-lapse mode is an extension of the original GigaPan concept, scientists already are applying the visualization techniques to other types of Big Data. Carnegie Mellon's Bruce and Astrid McWilliams Center for Cosmology, for instance, has used it to visualize a simulation of the early universe performed at the Pittsburgh Supercomputing Center by Tiziana Di Matteo, associate professor of physics.

"Simulations are a huge bunch of numbers, ugly numbers," Di Matteo said. "Visualizing even a portion of a simulation requires a huge amount of computing itself." Visualization of these large data sets is crucial to the science, however. "Discoveries often come from just looking at it," she explained.

Rupert Croft, associate professor of physics, said cosmological simulations are so massive that only a segment can be visualized at a time using usual techniques. Yet whatever is happening within that segment is being affected by forces elsewhere in the simulation that cannot be readily accessed. By converting the entire simulation into a time-lapse GigaPan, however, Croft and his Ph.D. student, Yu Feng, were able to create an image that provided both the big picture of what was happening in the early universe and the ability to look in detail at any region of interest.

Using a conventional GigaPan camera, Janet Steven, an assistant professor of biology at Sweet Briar College in Virginia, has created time-lapse imagery of rapid-growing brassicas, known as Wisconsin Fast Plants. "This is such an incredible tool for plant biology," she said. "It gives you the advantage of observing individual plants, groups of plants and parts of plants, all at once."

Steven, who has received GigaPan training through the Fine Outreach for Science program, said time-lapse photography has long been used in biology, but the GigaPan technology makes it possible to observe a number of plants in detail without having separate cameras for each plant. Even as one plant is studied in detail, it's possible to also see what neighboring plants are doing and how that might affect the subject plant, she added.

Steven said creating time-lapse GigaPans of entire landscapes could be a powerful tool for studying seasonal change in plants and ecosystems, an area of increasing interest for understanding climate change. Time-lapse GigaPan imagery of biological experiments also could be an educational tool, allowing students to make independent observations and develop their own hypotheses.

Source: PhysOrg - Provided by Carnegie Mellon University

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 
By Admin (from 30/07/2011 @ 14:00:20, in ro - Stiinta si Societate, read 1433 times)

 Pana in 2030 e nevoie de o crestere cu 40 milioane tone a efectivelor de peste de acvacultura pentru a raspunde nevoilor umanitatii.  In 2005 au fost capturate 85 milioane de tone de pesti marini si 9,6 milioane tone de peste de apa dulce. Din pescuit si acvacultura s-au obtinut 141,6 milioane de tone. 107,2 milioane de tone au fost consumate de oameni, restul in scopuri non-alimentare. Fiecare om mananca in medie 16,6 kg de peste pe an. 2,6 miliarde de oameni sunt dependenti de peste, ca sursa de proteine. In fiecare an pier 300.000 de mamifere marine, ramanand captive in plase si sfarsind prin asfixiere.

Un raport al Programului Natiunilor Unite pentru mediu stipuleaza faptul ca actiunea combinata a schimbarilor climatice, pescuitul in exces si poluarea mondiala ar putea compromite drastic rezervele de peste in deceniile urmatoare. Schimbarile climatice agraveaza situatia, distrugand recifele coraliene si siturile de reproducere a unor specii de pesti (in special ton). In acelasi timp, modifica curentii marini care transporta plancton si pesti mici, ce constituie baza lantului alimentar al oceanelor. O incetinire a vitezei curentilor marini, consecinta posibila a incalzirii climatice, poate intrerupe timp de un secol deplasarile de substante nutritive spre zonele de pescuit cele mai importante.

Tonul, pescuit in exces

 Tonul rosu isi traieste probabil ultimii sai ani in Mediterana si Atlantic. Si asta datorita autorizarii, de catre Comisia pentru conservarea tonului, a pescuitului acestei specii in exces, adica 29.500 tone de ton pe an (specia Thunnus thynnus). O cantitate dubla decat cea recomandata de comitetul stiintific din cadrul aceleiasi comisii. Daca se pescuiesc peste 15.000 tone pe an in aceste regiuni, reinnoirea stocului nu mai poate fi asigurata.

Exploatarea tonului a atins un nivel niciodata egalat. Daca se adauga si cantitatile de ton pescuit ilegal, cifrele ajung la 50.000 tone anual. Singura consolare o constituie faptul ca nu pot fi pescuiti pesti care au o greutate mai mica de 30 kg. Pe de alta parte pescuitul nu e limitat in luna iunie, perioada in care populatiile de ton isi depun icrele si in care acesti pesti sunt extrem de vulnerabili.

Cetacee amenintate

 Delfinii si marsuinii ar putea disparea in unele mari si zone oceanice, datorita utilizarii anumitor plase de pescuit. In special in Marea Neagra, in care aceste animale sunt ucise anual cu miile, in largul coastelor Africii de Vest sau ale Americii de Sud. Aproape 1.000 de balene au aceeasi soarta. In 2002 Uniunea Europeana a interzis folosirea plaselor aflate in deriva, o decizie respectata partial.

DORIN MARAN - magazin.ro

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 
By Admin (from 30/07/2011 @ 11:00:25, in it - Video Alerta, read 1668 times)

Costruire un elicottero a propulsione umana. Era il sogno più grande di Leonardo da Vinci, che alla fine del '400 provò a far volare la sua “vite aerea”. Ma ancora oggi c'è chi tenta di realizzarlo: tutti i partecipanti al Premio Sikorsky, istituito nel 1980 dall'American Helicopter Society e ancora senza un vincitore. Gli ultimi a cimentarsi nell'impresa sono stati gli studenti della  A. James Clark School of Engineering, dell'Università del Maryland (MD, USA) che lo scorso 11 maggio hanno messo alla prova il loro velivolo a pedali, Gamera.

Durante il test, l'elicottero pilotato da Judy Wexler si è alzato davvero in volo, ma solo per quattro secondi: un tempo insufficiente ad aggiudicarsi il premio. Infatti, le regole ferree della gara prevedono che, per vincere, il velivolo alimentato a pedali debba restare in aria per almeno 60 secondi a un'altezza di tre metri da terra. Un obiettivo difficile da raggiungere, ed è forse per questo che in trent'anni ci avevano provato solo altre due squadre: nel 1989 gli studenti della California Polytechnic State University (San Louis Obipso, USA), con Da Vinci III, e nel 1994 quelli della Nihon University (Tokyo, Giappone), con Yuri I.

Fonte: galileonet.it

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 

Concrete pavements are made by mixing cement with water, sand, and "virgin aggregates" obtained from rock quarries located in the proximity of the construction site. In Indiana most of these aggregates are quarried limestone.

"Some parts of Indiana have plenty of quarries near highway construction sites," said Nancy Whiting, a scientist with the Applied Concrete Research Initiative at Purdue's School of Civil Engineering. "In other places, it's more difficult to find quality aggregate. If you have to drive 50 or 100 miles to get a good quality aggregate, it's going to be much more cost effective to use recycled materials by crushing the concrete you have in place."

Concrete recycling may cut highway construction cost, landfill use

Whiting is leading the concrete recycling project funded by INDOT through the Joint Transportation Research Program with Jan Olek, a Purdue professor of civil engineering, postdoctoral research associate Jitendra Jain and graduate research assistant Kho Pin Verian.

"If you are going to pave, you may have to remove the old concrete and break it into pieces anyway, so recycling makes sense," Olek said. "And you avoid putting it in landfills."

Jain gave a research presentation about the work earlier this month during a meeting of the American Concrete Institute in Tampa, Fla.

The researchers are testing concrete mixtures that contain varying percentages of recycled concrete. They also are developing cost-analysis software that will enable the state and construction contractors to estimate how much they could save by using recycled concrete. Crushing old concrete pavements into aggregate that can be recycled in new concrete can potentially reduce materials costs by 10 percent to 20 percent, depending on whether any quarries are located near construction sites.

"Whether that would mean a comparable reduction in overall construction costs is part of what our research will determine," Whiting said.

Also involved in the work are Mark Snyder, an engineering consultant based in Pittsburgh, and Tommy Nantung, a project administrator at INDOT. Indiana currently allows the use of "recycled concrete as aggregate," or RCA, as a base layer to support new pavements. However, no existing specifications allow for use of this material in new concrete mixtures. The goal of the research project is to extend the use of the crushed concrete for manufacturing of mixtures that can be used to construct the pavement itself.

The team will finalize a report early next year, providing guidelines and recommendations to help create design and material standards. Standards are needed to control the quality of RCA and its proper use in creating the new concrete.

"Various other states have used crushed concrete as aggregate, but there has been no standardization, so the end result hasn't always been good," Whiting said. "We are trying to show INDOT that it can work and how to be consistent about getting a good product."

One aim is to ensure resistance of the RCA to cracking due to freezing and thawing cycles the pavements are exposed to during winter. Some aggregates are more susceptible to cracking than others. The focus of the standards will be on test methods for freeze-thaw durability and absorption of water and deicing chemicals.

The researchers are working with industry to produce nearly 400 test specimens of varying sizes and shapes containing different percentages of recycled aggregate. Concrete taken from State Route 26 when it was recently repaved in Lafayette has been crushed for use as RCA for the project.

"Slabs of concrete have been crushed into aggregate by Milestone Contractors LP under the direction of J. Beland," said Whiting.

A commercial concrete plant in Lafayette operated by Irving Materials Inc. is mixing the material. In addition, Jay Snider and Calvin Kingery of Irving Materials as well as Dick Newell of Milestone Contractors are working alongside the researchers, helping with issues ranging from adjusting mixture proportions to placement of trial slabs in the field.

Industry partners helped found the Applied Concrete Research Initiative in 2008 along with INDOT and academia, and are providing their services free of charge.

"They are doing this as a courtesy to us," Olek said. "This type of collaboration with practitioners is critical with respect to implementation of laboratory derived materials and technologies in the field."

More information: Predicting Long Term Durability of Concretes with Recycled Concrete as Coarse Aggregates

ABSTRACT:
 
The use of recycled concrete (RCA) as coarse aggregates in concrete is a sustainable, cost-effective alternative to disposing the old concrete pavements. Previous studies indicated that replacing up to 30% of the original (virgin) coarse aggregate in the mixture with RCA will have no negative effects on the freeze-thaw (F/T) resistance and mechanical properties of hardened concretes. In the present study, RCA was used in both plain and fly ash (20% of Class C fly ash) concretes to substitute for crushed limestone coarse virgin aggregates at four different replacement levels (0%, 30%, 50%, and 100%). The long-term durability of all concrete mixtures was evaluated by determining the F/T resistance (ASTM C666 procedure A), scaling resistance (ASTM C672), and rapid chloride penetration (RCP) resistance (ASTM C1202). In addition, the electrical impedance spectroscopy (EIS) measurements were performed on the same concrete specimens that were used for RCP test. EIS spectra were obtained using a Solartron™ 1260 gain-phase analyzer. A frequency range of 1 Hz–10 MHz using a 250 mV AC signal was employed, with 10 measurements per decade. The relationship between the values of final charge passed and bulk resistance obtained from EIS will be used to evaluate the effects of increase in temperature on charge passed during RCP for concretes with RCA. The different test results from this study would be useful to optimize the replacement levels as well as preferred tests to predict long-term durability of concretes with RCA.

Source: Physorg - Research Provided by Purdue University

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 

We all make sure we've got our keys, wallet and phone before we head out the door, but more often than not, we are carrying around things that are better left at home. Some items we carry on a daily basis can be virtually impossible to replace, and others may leave us at risk for identity theft in the event of loss. We checked in with the personal finance experts at LearnVest to find the top 10 things you shouldn't carry in your purse or wallet.

Social Security Card

"You may carry it around thinking you need a back-up source of ID, but these days you don't really need it," says Maria Lin, editor in chief at Learnvest. If your Social Security card gets in the wrong hands, someone could open a credit card, apply for a loan, or even buy a car with the information. It's nine digits, just memorize it.

Your Passport

If you're traveling internationally, of course you can't leave your passport at home, but you can leave it in the hotel safe. When you are abroad, make a photocopy of your passport to have in your wallet for identification along with your driver's license. "If you lose your passport or get mugged in a foreign country, it's such a horrible hassle," says Lin. "You have to go to the embassy, and it's a vacation nightmare." If you're traveling in the U.S., use your driver's license instead. "Your passport is such a primo document for your identity, if someone gets a hold of it, you can really put yourself at risk for identity theft," says Lin.

Passwords/Pass codes

Although most PIN numbers are only four digits long, some people still write them down so they don't forget. "If you store any type of ATM password or even a code for your home alarm in your wallet, you have basically gifted a thief with access to your life," says Lin. If you absolutely can't remember important pass codes, store them digitally on a password-protected phone, but never write them down and leave them in your wallet or purse

A Non-Password Protected Phone

Today, many people have smart phones that allow them instant access to bank accounts, PayPal accounts, medical records, and more. Even if your phone only accesses e-mail, a thief could easily search for banking or ATM passwords or addresses, according to Lin. "Think about all the things you have digitally stored on your phone. You have to have it behind password protection. This way a thief can still erase your phone's memory and use it for themselves, but they won't have access to your data."

Your Checkbook

"As innocuous as it seems, your checkbook has your bank account number and routing number on it, your address, and possibly imprints of your signature," says Lin. Lin says that if you know you're going to need to write a check one day, peel off one check out of your book and take it with you. If you know you're going to need to write multiple checks in one day, go ahead and take your checkbook, but don't get into the habit of carrying it around with you all the time, Lin says. "You want to prevent someone's ability to just start writing out your blank checks and cashing them."

Too Many Credit Cards

"A lot of people put all their cards in their wallet and carry them with them at all times," says Lin. "But if your wallet gets lost or stolen, that means you're going to have to sit and cancel every single one, and wait a week without any credit cards before you receive a replacement." Only carry the one or two cards you use on a daily basis and a backup, and leave others at home. Also make sure you keep photocopies of the front and back of each card at home, Lin advises. The 1-800 number to call and report a lost or stolen card is very often on the back of your card -- which doesn't do you a lot of good once the card is no longer in your possession.

Too Much Cash

Lin offers the following rule of thumb when it comes to carrying cash: Bring only as much with you as you're willing to lose. "It's good to have a little cash on you at all times for emergencies, but you don't want to carry so much that you're going to feel a real hit if your wallet gets stolen." For people on a "cash diet," Lin recommends bringing only as much cash to cover the day's expenses.

Gift Cards/Certificates

"A lot of people carry these around thinking, 'I never know when I'm going to be passing this store,' but chances are, you're going to forget about it anyway, and if your wallet gets stolen, it's one of the first thing thieves are going to use," Lin says. Gift cards and gift certificates are just like cash -- they don't require ID for use. "Try to leave it at home and take it with you only when you are consciously going to shop at that store," Lin says. "Make it a special excursion; it's a treat to have free money to spend."

Jewelry or USB Devices

"It may sound silly, but if you're changing earrings or heading from a business meeting, it's very possible you may forget and toss these things in the zipper compartment of your wallet," says Lin. USB devices can be bad news in the hands of thieves if they contain confidential files. "It would be horrible to get your wallet stolen any day, but if you're also losing your grandmother's earrings or a presentation you've been working on for months, it's even worse!"

Receipts

Sometimes receipts can have your credit card information on them, as well as your signature, which thieves could do a lot of damage with. Additionally, if you've just purchased a big-ticket item like a new computer or jewelry, you may need that receipt for warranty purposes. "If you're planning to use your receipts for expense purposes at work, those few hundred dollars of business receipts can just vanish and your employer might not be so understanding," says Lin. "Get in the habit of taking out your receipts every night instead of carting them around with you."

Source: finance.yahoo.com - Author: Kathryn Tuggle

Articolo (p)Link Commenti Commenti (0)  Storico Storico  Stampa Stampa
 
Ci sono 5935 persone collegate

< luglio 2019 >
L
M
M
G
V
S
D
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
       
             

Titolo
en - Global Observatory (605)
en - Science and Society (594)
en - Video Alert (346)
it - Osservatorio Globale (503)
it - Scienze e Societa (555)
it - Video Alerta (132)
ro - Observator Global (399)
ro - Stiinta si Societate (467)
ro - TV Network (149)
z - Games Giochi Jocuri (68)

Catalogati per mese - Filed by month - Arhivate pe luni:

Gli interventi piů cliccati

Ultimi commenti - Last comments - Ultimele comentarii:
Hi, it's Nathan!Pretty much everyone is using voice search with their Siri/Google/Alexa to ask for services and products now, and next year, it'll be EVERYONE of your customers. Imagine what you are ...
15/01/2019 @ 17:58:25
By Nathan
Now Colorado is one love, I'm already packing suitcases;)
14/01/2018 @ 16:07:36
By Napasechnik
Nice read, I just passed this onto a friend who was doing some research on that. And he just bought me lunch since I found it for him smile So let me rephrase that Thank you for lunch! Whenever you ha...
21/11/2016 @ 09:41:39
By Anonimo


Titolo

Latest NEWS @
www.TurismoAssociati.it

Non-Hodgkin lymphoma cured by CANNABIS. The video of Stan and Barb Rutner.

Dr. Joycelyn Elders, U.S. surgeon general: Myths About Medical Marijuana in The Providence Journal, 2004.

Marihuana vindeca CANCERUL: marturii despre uleiul de cocos si canabis.

Yahoo Incorporated Mail. My account recovery information is incorrect. The Password Helper says my password can't be reset online. "First time signing in here?" message.

All information in a video about Donatio Mortis Causa and The Venus Project

What is TOR browser?

From Viet Cong to Team USA: Hanoi garment factory's Olympic transformation

Debt and dollar in demand, sterling and stocks stricken on trade war and Brexit

Republican support for Trump rises after racially charged tweets: Reuters/Ipsos poll

As Fed nears rate cut, policymakers debate how deep, and even if

U.S. diplomat vows to help South Korea, Japan resolve worsening dispute

War risk costs drag on UAE marine fuel sales, benefit Singapore: trade sources

Ultimele articole - Antena3.roVeste tragica pentru o familie! Un elev de noua ani a murit la doar doua zile dupa ce a aflat ca avea leucemie

Membru CSM, propunere fara precedent pentru taierea pensiilor magistratilor

Cântare?ul R. Kelly, acuzat de numeroase abuzuri sexuale, a pledat nevinovat. Va ramâne în continuare în arest

La câteva zile dupa ce s-a mutat în casa noua, o femeie a facut o descoperire de-a dreptul bizara în gradina: „Sunt blestemata?” (FOTO)

Sf. Ilie, tradi?ii ?i obiceiuri. Ce este interzis sa faci în aceasta zi

Întâlnire cruciala la Guvern între Eugen Teodorovici ?i primari. Ministrul Finan?elor vrea impozitarea pensiilor de lux





17/07/2019 @ 11:06:47
script eseguito in 959 ms