More information: Laser ablation isotope ratio mass spectrometry for enhanced sensitivity and spatial resolution in stable isotope analysis, James J. Moran, Matt K. Newburn, M. Lizabeth Alexander, Robert L. Sams, James F. Kelly, Helen W. Kreuzer, Rapid Communications in Mass Spectrometry, Article first published online: 12 APR 2011 DOI:10.1002/rcm.4985DOI: 10.1002/rcm.4985AbstractStable isotope analysis permits the tracking of physical, chemical, and biological reactions and source materials at a wide variety of spatial scales. We present a laser ablation isotope ratio mass spectrometry (LA-IRMS) method that enables δ13C measurement of solid samples at 50 µm spatial resolution. The method does not require sample pre-treatment to physically separate spatial zones. We use laser ablation of solid samples followed by quantitative combustion of the ablated particulates to convert sample carbon into CO2. Cryofocusing of the resulting CO2 coupled with modulation in the carrier flow rate permits coherent peak introduction into an isotope ratio mass spectrometer, with only 65 ng carbon required per measurement. We conclusively demonstrate that the measured CO2 is produced by combustion of laser-ablated aerosols from the sample surface. We measured δ13C for a series of solid compounds using laser ablation and traditional solid sample analysis techniques. Both techniques produced consistent isotopic results but the laser ablation method required over two orders of magnitude less sample. We demonstrated that LA-IRMS sensitivity coupled with its 50 µm spatial resolution could be used to measure δ13C values along a length of hair, making multiple sample measurements over distances corresponding to a single day’s growth. This method will be highly valuable in cases where the δ13C analysis of small samples over prescribed spatial distances is required. Suitable applications include forensic analysis of hair samples, investigations of tightly woven microbial systems, and cases of surface analysis where there is a sharp delineation between different components of a sample. © 2010 PhysOrg.com In their paper, published in Rapid Communications in Mass Spectrometry, they describe a process they’ve devised whereby hair samples are pulled apart, rather than burned as a whole before being measured by a mass spectrometer. Such a process could be used to reveal personal details about someone, such as what they eaten recently; clues that might provide forensic scientists insight into the behavior of victims of foul play for example, or reveal information as the whereabouts of the accused during the time frame surrounding a crime.Because traditional laser analysis techniques tended to obliterate entire samples as they burned all of its parts together as a whole (leaving their gases to be released and measured in a spectrometer) Moran and his team chose to use a less destructive type of laser that uses only ultraviolet light (similar to the kind used for LASIK eye corrective surgery). They discovered that by doing so they could essentially break apart the individual pieces and parts of the hair as a hole was bored, which could then be burned separately and tested with the spectrometer; sort of like burning the filings left over when drilling into a piece of wood with an iron bit. Because hair grows slowly over time, it creates a timeline of sorts, with different stages representing differing days, weeks or even months The new technique allows for dozens of such holes up to be burned up and down the length of a single strand of hair, retrieving different samples that represent different points in time. Then, by studying the different stages of that timeline, analysts are able to piece together a historical picture of what someone has been eating during different times in the past.Currently the technique only looks at carbon isotopes released when hair is burned, which is how a historical diet is put together; subsequent experiments however will look at oxygen and nitrogen isotopes as well, to get a better picture of water, sulfur and other mineral intakes which could help identify other environmental circumstances prior to the sample being taken. Laser hair removal: No training required? Citation: New forensic laser technique for hair analysis can reveal historical data (2011, April 29) retrieved 18 August 2019 from https://phys.org/news/2011-04-forensic-laser-technique-hair-analysis.html Explore further Image: Wiley/Rapid Communications in Mass Spectrometry, DOI:10.1002/rcm.4985 (PhysOrg.com) — Using a new laser technique, Jim Moran and his colleagues at Pacific Northwest National Laboratory, have devised a method of separating out the parts of hair samples that can reveal details about the recent history of the person to whom it belongs. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
There have been reports of unscrupulous journals printing research papers without proper vetting, and other reports suggesting that there exists a black market in paper authorship. This new investigation by Science, is the first to publish direct evidence of such a black market operating in China. Hvistendahl reports on one instance where a suspected black-marketeer was contacted to inquire about having a name applied to an existing research paper. The contact quoted different prices for having a name included, depending on whether the person paying wished to be listed as the primary writer, or as merely a co-author, or even as just one of the team members. No money changed hands, as that would have been unethical for a Science reporter, but Hvistendahl reports that the paper that had been part of the earlier investigation showed up at a later date published in a reputable journal, along with different names attributed to the research effort—names of people that had all bought their way on.Hvistendahl notes that such a black market has arisen in China due to the enormous pressure Chinese researchers are feeling to publish something. In that country, it appears having one’s name attached to a research paper, matters more than actually conducting research. Hvistendahl also reports that people in China are willing to pay tens of thousands of dollars for the “honor” of having their name printed as an author on a research paper.Hvistendahl writes that Science’s undercover investigation revealed a thriving black market in China for paper authorization, which includes “shady agencies, corrupt scientists, and compromised editors.” The undercover operation was conducted over a five month period and resulted in numerous examples of people at all levels of research in China participating in the black market in one way or another. They also found that it was possible to pay for someone to write a paper, attach a name and then submit and have it published in a reputable international journal—so long as the research it described passed a traditional vetting process.The investigative team also found doctors and others engaged in medical research that were willing to openly admit that the black market for research papers is thriving in China. All in all, the investigative team contacted 27 agencies involved in helping researchers get their work published—only five of them refused an offer to pay for adding a name to a research paper. Research paper publishing sting reveals lax standards of many open-access journals Citation: Investigation reveals black market in China for research paper authoring (2013, November 29) retrieved 18 August 2019 from https://phys.org/news/2013-11-reveals-black-china-paper-authoring.html Journal information: Science More information: China’s Publication Bazaar, Science 29 November 2013: Vol. 342 no. 6162 pp. 1035-1039. DOI: 10.1126/science.342.6162.1035 © 2013 Phys.org (Phys.org) —The journal Science has uncovered, via investigation, a thriving black market in science paper authoring—people are paying to have their names added to papers that have been written to describe research efforts. Mara Hvistendahl was the lead investigator and author of a paper published by Science, describing the operation and what was found. Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Explore further Secure information transmission over 500m fiber links based on quantum technologies In a recent study now published in Light: Science & Applications, Ming Zhang, Lan-Tian Feng and an interdisciplinary team of researchers at the departments of quantum information, quantum physics and modern optical instrumentation in China, detailed a new technique to generate photon-pairs for use in quantum devices. In the study, they used a method known as four-wave mixing to allow three electromagnetic fields to interact and produce a fourth field. The team created the quantum states in a silicon nanophotonic spiral waveguide to produce bright, tunable, stable and scalable multiphoton quantum states. The technology is comparable with the existing fiber and integrated circuit manufacturing processes to pave the way to engineer a range of new generation photonic quantum technologies for applications in quantum communication, computation and imaging. The multiphoton quantum sources detailed in the work will play a critical role to improve the existing understanding of quantum information. Characterization of biphoton polarization-entangled states. (a) and (b) are twofold coincidences as a function of the idler polarizer angle when the signal polarizer angle was kept at 0° (red) and 45° (black), respectively. The error bar was obtained from the square root of the experimental data. (c) and (d) give the real (Re) and imaginary (Im) parts of the ideal density matrix and the measured density matrix of the biphoton entangled state from frequency channels ±5, respectively. The fidelity was 0.95 ± 0.01, confirming that the generated biphoton quantum state was of high quality and very close to the ideal maximally entangled states. Credit: Light: Science & Applications, doi: 10.1038/s41377-019-0153-y Schematic configuration of the experimental system to generate and characterize the multiphoton quantum state with a silicon nanophotonic waveguide. A pulse erbium-doped fiber laser with a repetition rate of 100 MHz was used as the pump light. After a VOA and a prefilter with a bandwidth of 100 GHz, the pump light was input into a Sagnac loop to generate the polarization-encoding quantum state. A postfilter with a bandwidth of 200 GHz was used to block the pump light. A DWDM filter was used to demultiplex photon pairs into the corresponding frequency channels, and a normal architecture for polarization state tomography was used to ascertain the quality of the entangled states. VOA variable optical attenuator, HWP half waveplate, PBS polarization beam splitter, QWP quarter waveplate, PC polarization controller, SNSPD superconducting nanowire single-photon detector. Credit: Light: Science & Applications, doi: 10.1038/s41377-019-0153-y Zhang et al. constructed the experimental setup in three parts to contain the (1) pump-laser modulator, (2) the photon source and (3) the state analyzer. In the pump-laser modulator they introduced a linearly polarized pulse erbium-doped fiber laser as the pump source with a repetition frequency of 100 MHz and a pulse duration time of 90 femtoseconds (fs). The scientists coordinated the pump light to pass through a 100 GHz bandwidth pre-filter, followed by a polarization controller (PC) and an optical circulator to finally couple into the photon source. They calculated the coherence time of the pulse laser light to be 20 picoseconds (ps) after going through the 100 GHz bandwidth prefilter and the propagation loss in the silicon spiral waveguide was approximately 1 dB/cm. Compared to multiphoton quantum states proposed with previous Spontaneous Four Wave Mixing (SFWM) processes, the present work used a silicon nanowire source with near-zero broadband dispersion. The experimental setup with the silicon nanowire did not demonstrate Raman scattering noise, which therefore greatly enhanced the number of photon pairs generated. Unlike with microresonators, Zhang et al. did not need to tune the operation wavelength in the experimental setup since they used silicon spiral waveguides instead. The scientists used grating couplers to couple-in the pump light and couple-out the generated photon pairs in the setup. As part of the photon source, Zhang et al. used a configuration with a Sagnac interferometer – a popular and self-stabilized scheme to generate polarization-entangled states. The experimental Sagnac interferometer contained two half-wave plates (HWPs), two quarter wave plates (QWPs), a polarization beam splitter (PBS) and the silicon spiral waveguide approximating a length of 1 cm to form a simple structure and compact footprint (170 x 170 µm2). The scientists used the combined HWP and QWP inserted between the PBS and the chip to control optical polarization and maximize the coupling efficiency of a photon pair. In the experiment, the on-chip generated photon pairs (idler and signal photons) could be superposed together in both directions (clockwise and counterclockwise) for output from the Sagnac loop. At this point, the scientists used a dense wavelength-division-multiplexing (DWDM) filter (fiber-optic transmission technique) to separate the signal and idler photons, or demultiplex them. They were thus able to freely select the photon pairs of any combined frequency channel via frequency detuning. The scientists noted that after going through the DWDM filters, the polarization and quantum states of the photon-pairs were unchanged. More information: Ming Zhang et al. Generation of multiphoton quantum states on silicon, Light: Science & Applications (2019). DOI: 10.1038/s41377-019-0153-y Lucia Caspani et al. Integrated sources of photon quantum states based on nonlinear optics, Light: Science & Applications (2017). DOI: 10.1038/lsa.2017.100 Alán Aspuru-Guzik et al. Photonic quantum simulators, Nature Physics (2012). DOI: 10.1038/nphys2253 Yin-Hai Li et al. On-Chip Multiplexed Multiple Entanglement Sources in a Single Silicon Nanowire, Physical Review Applied (2017). DOI: 10.1103/PhysRevApplied.7.064005 In the present work, Zhang et al. generated four-photon polarization encoding quantum states using degenerated spontaneous four-wave mixing (SFWM) in a silicon spiral waveguide. The scientists first demonstrated biphoton Bell entanglement quantum states with high brightness (270 kHz) and a high coincidence to accidental ratio (CAR, approximating 230) at a low pump power (120 µW). Thereafter, using the two biphoton Bell entangled states, Zhang et al generated the four-photon quantum state (with a pump power as low as 600 µW). The scientists projected this quantum product state to form a Greenberger-Horne-Zeilinger (GHz) state (i.e. a state in quantum information theory with at least three subsystems or particles) with 50 percent probability for further use in quantum information applications. Experiment results of two-photon coincidences between different combinations of the selected five pairs of signal-idler channels. Here the pump power injected to the Sagnac loop is 120 μW. The two-photon coincidences were measured for the selected five pairs of signal-idler channels. Credit: Light: Science & Applications, doi: 10.1038/s41377-019-0153-y Schematic diagram of the experimental system to generate and characterize the multiphoton quantum states with a silicon nanophotonic waveguide. The experimental setup contains a (1) pump laser modulator, (2) the photon source and (3) the state analyzer. The scientists used the combined HWP (half-wave plates, red) and QWP (quarter-wave plates, blue) inserted between the PBS (polarization beam splitter, green) and the chip to control optical polarization and maximize the coupling efficiency of a photon pair. Credit: Light: Science & Applications, doi: 10.1038/s41377-019-0153-y Citation: Generating multiphoton quantum states on silicon (2019, May 9) retrieved 18 August 2019 from https://phys.org/news/2019-05-multiphoton-quantum-states-silicon.html The scientists generated multiphoton quantum states using a single-silicon nanophotonic waveguide and detected four-photon states with a low pump power of 600 µW to achieve experimental multiphoton quantum interference verified with quantum state tomography. Zhang and Feng et al. recorded the quantum interference visibilities at a value greater than 95 percent with high fidelity. The multiphoton quantum source is fully compatible with on-chip processes of quantum manipulation and quantum detection to form large-scale quantum photonic integrated circuits (QPICs). The work has significant potential for multiphoton quantum research. Multiphoton quantum sources are critical to build several practical platforms for quantum communication, computation, simulation and metrology. Physicists have made great efforts to realize high quality, bright and scalable multiphoton quantum states in previous work, to activate powerful quantum technologies by multiplexing several biphoton sources to generate eight-photon and 10-photon entanglement. However, the efficacy of such multiplexing systems decreased with the number of entangled photons. At present, quantum photonic integrated circuits (QPCIs) and silicon-on-insulator (SOI) technology remain promising to realize high quality photon-pair sources. Silicon has several advantages as a substrate to implement QPICs, which include third-order optical nonlinearity of the material and ultra-high refraction index contrast for applications as SOI nanophotonic waveguides. Silicon is also compatible with complementary metal-oxide semiconductor (CMOS) processes—attractive for large-scale photonic integration. While these advantages have allowed physicists to experimentally realize biphoton quantum sources, multiphoton quantum states on silicon still remain to be generated and reported. Zhang et al. then characterized the quality of the biphoton state generated in the experiment. For this, they selected five pairs of frequency channels used in the study to generate the signal and idler photons, to test the stability of the system. They measured the two-photon coincidences between different combinations of signal and idler channels and showed that the crosstalk was negligible for most frequency channels. After calculating the maximal polarization-entangled Bell state, they confirmed the existence of entanglement and high fidelity of the biphoton state. They credited the high coincidence-to-accidental ratio (CAR) observed to the ultralow nonlinear noise in the setup; necessary to generate multiphoton entanglement for further quantum information applications. For complete characterization, the scientists connducted quantum state tomography to reconstruct the experimental state density matrix architecture by completing multiple measurements of the relevant quantum state. The results confirmed that the generated biphoton quantum states are of high quality to approach the ideal maximally entangled states. The scientists then conveniently generated multiphoton entangled states by multiplexing the biphoton states in different frequency channels. They obtained a fourfold coincidence rate and showed the observed four-photon state as the tensor product of two biphoton entangled Bell states. The four-photon interference patterns agreed with the theoretical prediction, to unfold differently from the previously observed biphoton entangled states. Based on the outcomes of a clear interference pattern and high interference visibilities, Zhang et al. verified the feasibility of the experimental technique to establish on-chip multiphoton quantum states. As before, the scientists obtained quantum state tomography of the four-photon quantum states to reconstruct the density matrix, yielding satisfactory results for further quantum information applications. In this way, the scientists experimentally demonstrated the generation of four-photon quantum states using a silicon nanophotonic spiral waveguide. Zhang et al. aim to improve the photon collection efficiency to increase the number of entangled photons in the system in the future. The multiphoton quantum state source developed in the study is compatible with contemporary fiber and chip-scale architectures for large scale production. Zhang et al. therefore propose the integration of the attractive features as a scalable and practical platform for future quantum processing applications. Characterization of four-photon polarization-encoding quantum states. (a) and (b) are fourfold coincidences as a function of the idler polarizer angles when the signal polarizer angles were kept at 0° (red) and 45° (black), respectively. The error bar was obtained from the square root of the experimental data. (c) and (d) give the real (Re) and imaginary (Im) parts of the ideal density matrix and the measured density matrix of the four-photon quantum states, respectively. The fidelity was 0.78 ± 0.02, which is completely satisfactory for further quantum information processing. Credit: Light: Science & Applications, doi: 10.1038/s41377-019-0153-y Journal information: Light: Science & Applications © 2019 Science X Network , Nature Physics This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Kolkata: Following the carcass meat case that has already triggered a flutter in the state, various medical colleges and hospitals in the city have decided not to serve chicken among the patients as a precautionary measure.Most of the medical college and hospital authorities in the city have issued instructions to keep chicken out of the menu, in view of the rotten meat row. It has been learnt that top medical colleges in the city, including the multi super-speciality SSKM and the Calcutta Medical College and Hospital, have decided not to serve chicken among the patients, as it might create confusion among them. Also Read – Heavy rain hits traffic, flightsAccording to sources, patients in the government hospitals or medical colleges get chicken once or twice a week. But for the last few days, the hospital authorities have asked the catering companies to not provide chicken to the patients, until the dead meat debacle gets sorted. Instead of chicken, the patients are getting fish or egg curry, depending on their choice.It may be mentioned here that in SSKM Hospital, patients get chicken once in a week during lunch. If any patient is willing to have vegetarian dishes, they can easily opt for them. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedAccording to a senior official of SSKM, ever since the matter came to light, there has been an impact of the incident on the patients as well. Many patients have also become unwilling to have chicken. “There is no point in serving chicken at a time when a huge amount of rotten meat has been recovered from various parts of the state and the matter is still under investigation,” he said.The other list of food items on offer remains unchanged. Like usual, the patients are getting milk, bread and banana for breakfast. On some days of the week, the patients the getting vegetable dishes, while on the other days they can opt for fish or egg. A senior official of Calcutta Medical College and Hospital said that the revised menu will continue till further order issued in this regard.
Taking Prime Minister Narendra Modi’s recently launched “Make in India” forward, Intimate Apparel Association of India (IAAI) organised a 2-day trade fair which focussed on intimate wear manufacturing in India. Santosh Kumar Gangwar, Minister of State for Textiles (Independent Charge) inaugurated the exhibition on Wednesday. The Joint Secretary for Textile Exports, Sunaina Tomar was also present. A white paper on ‘Make in India, Make for the World: Developing India as a quality intimate supplier for global markets’ was also simultaneously released by the Textile Minister. Also Read – ‘Playing Jojo was emotionally exhausting’This year, in the fourth edition of India’s biggest intimate apparel trade fair, Galleria Intima will be in focus in order to to transform it as the next major hub of intimate wear manufacturing. The exhibition showcased everything from fibres to
Kolkata: West Bengal Chief Minister Mamata Banerjee Thursday said that unity in diversity is India’s strength, and asked people to uphold the spirit and remain united. Referring to a Sanskrit phrase found in Maha Upanishad, ‘Vasudhaiva Kutumbakam’, meaning, “the world is one family”, the chief minister, on International Human Solidarity Day, urged everybody to stay united and fight the divisive forces. “On International Human Solidarity Day, let us pledge to uphold the spirit of ‘Vasudhaiva Kutumbakam’ in truest sense. Unity in diversity is India’s strength,” Banerjee tweeted. “We must all be united and fight against the forces which seek to divide us for selfish reasons,” she added. The United Nations’ (UN) International Human Solidarity Day is annually held on December 20 to celebrate unity in diversity. It also aims to remind people on the importance of solidarity in working towards eradicating poverty.
“I like my money right where I can see it: hanging in my closet.” – Carrie Bradshaw Fashionistas in town had a lovely time recently as they could feast their eyes upon a fabulous new collection launched. There could not be more perfect timing to launch the New Spring Summer Collection at Agashe, this year marking the celebration of their one year anniversary. They launched yet another fabulous spring summer collection with select prêt designers, new and old. Sheena Agarwal the owner and curator of Agashe is an image consultant and offers her expert guidance based on the look one aims. Also Read – Add new books to your shelfThey launched yet another fabulous spring summer collection with select prêt designers, new and old. Sheena Agarwal the owner and curator of Agashe is an image consultant and offers her expert guidance based on the look one aims.Agashe is an up market, multi designer Fashion and lifestyle store that offers both tradition and style infused with a breathe of modernity. The store hosts and offers over 60 of India’s luxury prêt fashion designers with varied options ranging from Rs 5,000 to 50,000. Agashe offers both Western as well as Indian garments, and accessories for fashion enthusiasts under one roof. This is the perfect spot for all avid shoppers to stop by browse and pick from the latest collections of designers like Pallavi Mohan, GARO, HUEMN, Urvashi Joneja, Duett Luxury, Fadh.K, Sumaan Natwani, and many others. Recently they unveiled their Spring Summer line (SS’17) with the fashion show as it celebrated the first year anniversary. Some of the city’s famous and stylish diva’s like Dimple Fouzdar, Sanjana Thandani, Rachna Sandhu, Lupita Saluja, Mallika Jain were part of the celebration. Shopaholics who like to keep themselves updated about the current fashion and trends would find good company in here surrounded by the latest designs in the SS’17 collection. The pret store in MG road, Gurgaon has launched about 30 new designers’ Spring Summer collection.
Kolkata: The Kolkata Municipal Corporation (KMC) launched its first phase of anti-dengue drives in the city ahead of the summer season on Saturday. About thousand people took part in the central rally, which was taken out from the KMC headquarters on S N Banerjee Road, to create awareness about the disease. Another couple of thousands took part in various rallies organised by 144 ward councillors as part of the first phase of the city’s battle against dengue. Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseThe central rally, which was attended by Deputy Mayor Atin Ghosh, the state Power minister Sobhandeb Chattopadhyay, special municipal commissioners Tapas Chowdhury and Shahzad Shibli, administrative officials of various departments, also had film actors, including Deb and Mimi, and former Indian Olympian Gurbux Singh and poet Chandril Bhattacharya. Deb and Mimi urged local residents not to allow water-logging in front of their homes and emphasised on preventive measures to control the disease. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataPeople were accompanied by a musical band, Chhau dancers and a group of musicians with dhol kartaal, who performed on various folk tunes of Bengal. Some of them held placards with thought-provoking messages aimed to create awareness about the disease donning costumes of Doraemon, Motu Patlu and Mickey Mouse. Lauding the initiative by the deputy mayor for organising such drives and bringing down the number of dengue cases last year, Hakim said the chances of dengue and malaria breakouts seemed bleak this year. But it is better to take precautionary measures, he said. Citing a recent incident, in which a few KMC workers were attacked by members of a household during a dengue drive, Hakim said: “Do not assault or attack civic workers who visit your home for inspection. I request your cooperation in this regard.” The second phase of the drive is scheduled to commence from July and continue till October.
New York: Most parents believe that an excessive late night use of gadgets has significantly hampered the sleep patterns of their teenaged children, leading to poor academic performance, researchers warn. According to them, 56 per cent of parents fall in this category. In the study, published by C.S. Mott Children’s Hospital National Poll on Children’s Health at the University of Michigan, 43 per cent of parents said their teenage children are struggling to fall asleep or wake up. Also Read – Add new books to your shelf’The poll suggests that sleep problems are common among teenagers and parents believe late-night use of electronics are a main contributor,’ said Sarah Clark, poll co-director at M.P.H. For the study, the researchers included responses from 1,018 parents with at least one child who are aged between 13 –18 years of age. Teenagers’ hectic schedules and homework load – as well as anxiety about school performance and peer relationships – are also seen by parents as contributing to sleep problems. Also Read – Over 2 hours screen time daily will make your kids impulsiveSome parents also reported that their child experienced occasional sleep problems (one to two nights per week) while 18 percent believe their teenage kids struggle with sleep three or more nights per week. In addition, 10 per cent of parents believe their teenage kids’ sleep problems are associated with their health conditions or medication. Other reasons of sleep disturbances included irregular sleep patterns due to homework or activities which accounted for 43 per cent, worries about school (31 per cent) and concerns about social life (23 per cent), the study noted. The parents have encouraged their children to try different strategies at home to help them cope up with sleep problems, including limiting caffeine in the evening (54 per cent), turning off electronics and cell phones at bedtime (53 per cent), having a snack before bed (44 per cent) and natural or herbal remedies, such as melatonin (36 per cent). Twenty-eight per cent of parents said their kids have also tried some type of medication to address sleep problems. “Parents whose teen continue to have frequent sleep problems, despite following recommendations for healthy sleep hygiene, may want to talk to a health care provider, for the well being of their kid,” said Clark.
There are roughly 175 miles between Pembrokeshire in Wales and the Salisbury Plain in England. The first represents the location of neolithic quarries from which stone was extracted some 5,000 years ago. The second is the famous Stonehenge ― a prehistoric shrine whose origins remain a subject of heated debate between scholars. The relation between the two places ― besides the distance ― has long been a subject of extensive research. While the ancient world was no stranger to monolithic structures which would be difficult to construct even by today’s standards, the difference between Stonehenge and other structures lies in a choice to neglect local stones and, shall we say, rather “import” them from a great distance.Long shadows from the early morning sun at StonehengeWith a number of questions still open, scientists on the Stonehenge case announced in February 2019, that they just might be one step closer to solving the mystery.A discovery by an archaeology team led by Professor Mike Parker Pearson of University College London’s Institute of Archaeology of massive stone-cutting tools found in Pembrokeshire has shed new light on this complex debate.Archaeologists claim to have found the prehistoric tools used to quarry the original standing stones that date from the earliest phases of Stonehenge, just after the religious site adopted its monumental stone features.View of the western half of the Preseli Hills taken from 1/2 mile north of Crymych on A478. Photo by Tony Holkham CC BY 3.0The tools were found on the northern slopes of the Preseli Hills in Pembrokeshire, southwestern Wales, where two former quarries were located.Experts who had used chemical analysis to track the bluestone from Stonehenge to Pembrokeshire claim that there are at least three more locations that were used to quarry stones for the sacred site in Salisbury Plain.View from Carn Menyn eastwards towards Foel Drygarn (centre-left) and Y Frenni (centre-right) in the distance. Photo by Tony Holkham CC BY SA 3.0The discovery includes several hammerstones used for inserting and forcing in the wedges, which would, in return, cause for the large parts of the stone to detach from the rock. The wedges were made from sandstone, and 15 of them have been discovered during this particular excavation.Related Video: Hunger Stone Warnings – Haunting past messages revealed on stones from droughtApart from the tools, traces of V-shaped slots were also discovered in two columns of what was once the Pembrokeshire quarry. The slots seem to have been fitted, but for some unknown reason, never used. It was as if the ancient stonemasons had left it there as evidence of their methods and work.StonehengeRegarding the discovery, as well as the implications it presents, Pearson gave a statement for the British archaeological journal Antiquity soon after they went public with the excavation results:Every other Neolithic monument in Europe was built of megaliths brought from no more than 10 miles away. We’re now looking to find out just what was so special about the Preseli Hills 5,000 years ago, and whether there were any important stone circles here, built before the bluestones were moved to Stonehenge.A standing stone in the Preseli Hills mountain range, Pembrokeshire, Wales. This stone is one of the bluestones from this area which were used to construct the inner circle of Stonehenge.Theories are currently being spawned on how and why were these prehistoric men so keen on crossing such a distance while transporting stones that weighed up to 4 tons each.As for transport, there are two dominant options. First of them ― and perhaps the most logical ― was that the stones were carried on rafts, or catamaran-like boats along the coast, and then transported via the Avon river to within 20 miles of Stonehenge’s location.The prehistoric monument of Stonehenge in England. Focus is on the grass.The second theory is presumed to be dominantly by land. The idea of transporting 79 huge pieces of stone across the country by land must have been a very strong demonstration of might ― one that could have symbolically consolidated a power struggle between rival tribes and clans that inhabited Britain in the third millennium B.C.In such case, they would probably be carried by stretchers, sleds or rollers facing an unforgiving terrain, besides the long distance. The use of rivers would be fairly limited in this case, therefore demanding tons of manpower to be employed constantly.These two options offer a solution on how the bluestones of Stonehenge were transported. However, “why” is an entirely different issue.Rare and beautifully executed Engraved illustration of Druids Worshiping at Stonehenge, England in Ancient Times Engraving from The Popular Pictorial Bible,By analyzing the bones excavated in the vicinity of the site, the scientists have determined that a number of them originated from the very area where the stones can be traced. Therefore, it is possible that the community that built Stonehenge had migrated from southwestern Wales, and possibly even brought the stones that hold such great cultural influence with them.Photography of Stonehenge at the sunsetSome scientists argue that perhaps the first stones that form the foundation of the Salisbury Plain might have served earlier as part of a similar structure, somewhere around Pembrokeshire.Read another story from us: Conservationists Aren’t Happy About New Spielberg Production Near StonehengeThis would mean that there was an original, proto-Stonehenge in Wales, before the one in England. If true, this theory could easily shake many notions regarding the origins, the culture and the ritual role of Stonehenge. However, evidence for such groundbreaking claims is yet to be found.