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. However, as physicists Robert Caldwell of Dartmouth College in Hanover, New Hampshire, and Albert Stebbins of Fermilab in Batavia, Illinois, point out, the Copernican principle has never been confirmed as a whole. In a recent paper published in Physical Review Letters called “A Test of the Copernican Principle,” the two researchers set out to prove the 500-year-old principle using observations of the cosmic microwave background (CMB).“The Copernican principle is a cornerstone of most of astronomy, it is assumed without question, and plays an important role in many statistical tests for the viability of cosmological models,” Stebbins told PhysOrg.com. “It is also a necessary consequence of the stronger assumption of the Cosmological Principle: namely, that not only do we not live in a special part of the universe, but there are no special parts of the universe – everything is the same everywhere (up to statistical variation). “It is a very handy principle, since it implies that here and now is the same as there and now, and here and then is the same as there and then. We do not have to look back in time at our current location to see how the universe was in our past – we can just look very far away, and given the large light travel time, we are looking at a distant part of the universe in the distant past. Given the Cosmological Principle, their past is the same as our past.”Cosmic DistortionWhen the universe was just 400,000 years old, matter and radiation decoupled and left a remnant radiation that still pervades the entire universe today. By measuring the tiny temperature fluctuations of this CMB radiation, scientists can learn things about the universe such as its shape, size, and rate of expansion. In the latter case, the observations show that the universe is expanding at an ever-accelerating rate, leading scientists to speculate about the existence of dark energy, new laws of gravity, and other possible – and often exotic – theories.But what if the universe’s accelerating expansion is just an illusion? As Caldwell and Stebbins explained, this scenario is entirely plausible if the Copernican principle is loosened a bit. If, instead of the universe being homogenous and isotropic as the Cosmological Principle states, there is rather “a peculiar distribution of matter centered upon our location,” then the universe would be centered on a low-density, matter-dominated void. Such a universe would be non-accelerating, and there would be no need for dark energy or other similar theories. That’s why it’s important to know if the Copernican principle is correct: it will ensure that CMB observations haven’t been misinterpreted to indicate cosmic acceleration when there is none. To test the principle, Caldwell and Stebbins developed a “CMB-distortion test”: they looked for deviations of the CMB spectrum from a perfect blackbody as might have been caused by a large, local void. A void or other “non-Copernican structure” would cause ionized gas to move relative to the CMB, and the Doppler-shifted CMB scattered toward us could contain detectable deviations from a blackbody. “In essence, we use the reionized Universe as a mirror to look at ourselves in CMB light,” the researchers explained. “If we see ourselves in the mirror, it is because ours is a privileged location. If we see nothing [i.e. no peculiar distortions] in the mirror, then the Copernican principle is upheld.”The Hubble BubbleAs an initial test, Caldwell and Stebbins focused on a universe model consisting of a simple, spherically symmetric void, which is also known as a “Hubble bubble.” This void universe resembles an open (low-density) universe embedded inside a flat (medium-density) universe. The size of the void depends on how gas is distributed throughout the universe. Basically, gas can exist in three zones – neutral, reflection, and Doppler – depending on its redshift. Depending on how these three zones overlap, the void can come in five sizes, from small to “superhorizon,” where the void encompasses the entire observable universe.Using their CMB-distortion test, the researchers calculated that only the smaller void models could lead to the type of distortion associated with a violation of the Copernican principle. Then, by analyzing data for the CMB spectrum, they were able to rule out nearly all of these non-Copernican Hubble bubble void universes – meaning the Copernican principle passed this first test. However, Caldwell and Stebbins also noted that other models – such as those with a higher density or smaller radius – may still exist that evade this test.The researchers added that this is not the first time that bits of the Copernican principle have been tested, but it is one of the first tests of the remaining radial inhomogeneity on very large scales. Caldwell explained that, in 1995, physicist Jeremy Goodman of Princeton proposed a similar test of spectral distortions. Goodman’s implementation resulted in a weaker constraint, or test, of the Copernican principle.“This [large-scale testing] is not easy to do because, when we look far away, we are looking back in time, and it is difficult to say whether what we see is due to changes with time, which does not violate the Copernican principle, or changes with distance, which does,” Stebbins explained. “Thus, it is a hard question to answer, which is why it has not been done.”More TestsIn the future, the scientists plan to further pinpoint the CMB distortions that could be caused by a local non-Copernican structure, and also apply the test to other more general universe models. These tests should be useful in potentially ruling out alternative hypotheses for dark energy, as Caldwell explained. More fundamentally, the tests could either verify the foundation of centuries of astronomical work, or – and the chance is slim – suggest that the Copernican principle may not be as certain as we think.“If our test of the Copernican principle were to fail, it would probably not be believed, and a variety of other observations would be required to test it,” Stebbins said. “If all these further tests confirmed the large void, then we would have to rethink our ideas about dark energy, or, namely, unthink them. “I think the scientific community would not be too unhappy with the idea of a large under-dense region – it is not hard to think of ideas of how they might come to be, even in the context of a hot big bang model. What is hard to understand is why we would be so close to the center of one. No doubt someone would come up with an ‘anthropic’ argument for it – but I’ve thought a bit about that, and don’t really think there is a salable anthropic explanation. (By the way, I don’t think there is a salable intelligent design reason, either.) In the end, we might have to live with the Walter Cronkite explanation ‘… and that’s the way it is …. ’”More information: Caldwell, R. R. and Stebbins, A. “A Test of the Copernican Principle.” Physical Review Letters 100, 191302 (2008). Copyright 2008 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. This image shows a cross-section of a void universe with an observer (O) in the center, in violation of the Copernican principle. CMB photons (yellow lines) can scatter off reionized gas, and some may lead to CMB distortions. Credit: Caldwell, R. R. and Stebbins, A. ©2008 APS. Explore further Earth not center of the universe, surrounded by ‘dark energy’: cosmologists report Citation: A Test of the Copernican Principle (2008, May 22) retrieved 18 August 2019 from https://phys.org/news/2008-05-copernican-principle.html The Copernican principle states that the Earth is not the center of the universe, and that, as observers, we don’t occupy a special place. First stated by Copernicus in the 16th century, today the idea is wholly accepted by scientists, and is an assumed concept in many astronomical theories.
Captive Zebra Finch Taeniopygia guttata at Bodelwyddan Castle Aviary, Denbighshire, Wales. Image: Arpingstone/Wikipedia. (PhysOrg.com) — In a recent study, in what is likely to stir some controversy, researchers from the Max Planck Institute in Germany have shown that finches in the wild, normally a monogamous type of bird, tend to cheat on their “spouses” and what’s more, it appears to be an inherited trait; but that’s not the end of it, the researchers also suggest in their paper, published in the Proceedings of the National Academy of Sciences, that such inherited traits may also exist in other species, including man. It has actually been known for quite some time that finches tend to stray, and while the male behavior seemed clear and well understood, the female behavior was somewhat of a puzzle. The males, by straying were spreading their seed around, thus keeping things in the finch world, richly diversified. But why would the females go along with the whole game, as there didn’t seem any reward for them?To find out, the team, led by Wolfgang Forstmeier, studied 1,554 zebra finches over five generations; taking DNA samples along the way. In addition to studying their natural behavior, they also swiped the eggs from some nests and deposited them in others to make sure the birds weren’t learning their errant behavior from a parent.What they found was that male finches with a father that strayed, were more likely to stray themselves, regardless of whether that father was around to help raise them. They also found the same was true for the females, a surprising result, but one that makes sense when you consider that if birds in any given area are to remain diversified, at least some of the females are going to have to stray as well; but not all, as clearly finches benefit from having nearly monogamous mates to help raise their young.The authors, even as they step out on a limb to suggest the same traits may hold true for human beings as well as for birds, immediately backtrack, making it clear they realized that there is far more going on when people stray, than when birds do so. Even so, it’s an interesting idea; one some people might use after learning about the results of this study, when looking for a rationale to excuse their behavior. More information: Female extrapair mating behavior can evolve via indirect selection on males, PNAS, Published online before print June 13, 2011, doi: 10.1073/pnas.1103195108AbstractIn many species that form socially monogamous pair bonds, a considerable proportion of the offspring is sired by extrapair males. This observation has remained a puzzle for evolutionary biologists: although mating outside the pair bond can obviously increase the offspring production of males, the benefits of such behavior to females are less clear, yet females are known to actively solicit extrapair copulations. For more than two decades adaptionist explanations have dominated the discussions, yet remain controversial, and genetic constraint arguments have been dismissed without much consideration. An intriguing but still untested hypothesis states that extrapair mating behavior by females may be affected by the same genetic variants (alleles) as extrapair mating behavior by males, such that the female behavior could evolve through indirect selection on the male behavior. Here we show that in the socially monogamous zebra finch, individual differences in extrapair mating behavior have a hereditary component. Intriguingly, this genetic basis is shared between the sexes, as shown by a strong genetic correlation between male and female measurements of extrapair mating behavior. Hence, positive selection on males to sire extrapair young will lead to increased extrapair mating by females as a correlated evolutionary response. This behavior leads to a fundamentally different view of female extrapair mating: it may exist even if females obtain no net benefit from it, simply because the corresponding alleles were positively selected in the male ancestors. Explore further Citation: Study shows genes may play a role in promiscuity (2011, June 14) retrieved 18 August 2019 from https://phys.org/news/2011-06-genes-role-promiscuity.html © 2010 PhysOrg.com Infidelity pays off for female Gouldian finches 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.
© 2015 Phys.org New form of sulfur discovered in geological fluids A conglomerate of researchers hailing from the CNRS and several universities, and organizations in France has found a possible cause for the higher concentrations of gold. They propose that under hydrothermal conditions, the trisulfur ion (S3-) plays a key role in the deposition of gold. Their findings have implications for the way scientists predict the location of gold deposits and may lead to as-yet-discovered sites. Using x-ray absorption spectroscopy, hydrothermal reactor measurements coupled with first-principle molecular dynamics, and thermodynamic modeling, they provide quantitative data for the effect of the trisulfur ion in hydrothermal conditions. Their work appears in the Proceedings of the National Academy of Sciences. According to Pokrovski et al., existing gold speciation studies ignore the trisulfur anion, S3-. Prior studies by this group and others have shown that the trisulfur ion exists in aqueous environments at high temperatures and pressures. For example, in previous research using in situ Raman spectroscopy, Pokrovski’s group demonstrated that this form of sulfur is stable in aqueous solutions in a temperature range of at least 200oC to ~700oC and 30bar. Trisulfur had been difficult to identify because at cooler temperatures S3- breaks down to sufate and sulfide in aqueous solutions. Their prior work provided an impetus for considering more than hydrogen sulfide and chloride, the trisulfur anion in analyzing gold transport and deposition.In an effort to quantify how S3- affects the concentration and precipitation of gold from aqueous hydrothermal fluids, Pokrovski et al. used model fluid systems comprised of gold metal and hydrogen sulfide, sulfate, and S3- and varied many of the system parameters such as temperature, pressure, redox potential, and acidity. Their data is from in situ X-ray absorption spectroscopy (XAS) and hydrothermal reactor measurements assisted by first-principles molecular dynamics (FPMD) and thermodynamic modeling.Their study reveals that while Au(HS)2- is the most stable species in aqueous solutions at moderate temperatures (<250oC), as the concentration of S3- increases with increasing temperature, the measured gold concentrations became significantly greater than in hydrogen sulfide solutions alone. Of the possible S3- ion complexes, Au(HS)S3- was found to be the most stable. They point out that their estimates are likely lower than the reality because in addition to Au(HS)S3- other gold-trisulfur species may be stable beyond the temperature and pressure conditions of their experiments.Their studies demonstrate three properties of S3- that could explain observations at certain gold deposit sites. These observations strongly argue for a change in the way ore deposition is modeled. First, the trisulfur ion serves to enhance gold extraction from deep seated magma or rocks. The trisulfur complex is stable and highly soluble, meaning that more gold can be found in a small amount of aqueous fluid compared to hydrogen sulfide and chloride complexes. Indeed, their data show gold concentration levels that coincide with some of the highest gold concentrations found in natural fluid inclusions trapped in minerals in gold ore deposit systems. These concentrations are much higher than what would be predicted with traditional modeling.Additionally, the S3- ion is sensitive to temperature, pressure, redox potential, pH as well as sulfur concentration. Their data demonstrate that only small changes in any one of these variables can result in a significant amount of gold from Au(HS)S3- precipitating in a very short amount of time. This may account for certain isolated locations containing an unusually large gold grades.Finally, S3- is highly selective for gold and, possibly, some other sulfur-loving metals (e.g., platinoids, molybdenum, rhenium). This kind of selectivity may account for the high concentration of gold in aqueous solutions as well as the metal signatures found in particular deposit sites. This may also account for oddities, such as the elevated molybdenum concentrations in porphyry systems below 500oC."Our findings show that one of the oldest metals, known from Antiquity, has yet to divulge all its secrets," says lead author Gleb Pakrovski. "We are just at the beginning of our understanding of geological fluids from the deep." Native gold nugget. Credit: public domain 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. Citation: Trisulfur anion helps explain gold deposits on Earth (2015, October 23) retrieved 18 August 2019 from https://phys.org/news/2015-10-trisulfur-anion-gold-deposits-earth.html Journal information: Proceedings of the National Academy of Sciences Explore further (Phys.org)—People have been excavating gold for thousands of years as a precious rare metal. Gold is in relatively low abundance in the Earth’s crust likely coming from the metallic core and from meteorites. For reasons that are not entirely known, even though the average amount of gold throughout the Earth’s crust is small, there are deposits containing gold in significantly greater concentrations than the crust’s average abundance. These deposits tend to be in locations of geological activity and are likely due to the action of hydrothermal fluids. However, the concentration of gold in deposits is still higher than what would be expected from solutions carrying gold-chloride or gold-hydrogen sulfide. More information: Gleb S. Pokrovski et al. Sulfur radical species form gold deposits on Earth, Proceedings of the National Academy of Sciences (2015). DOI: 10.1073/pnas.1506378112AbstractCurrent models of the formation and distribution of gold deposits on Earth are based on the long-standing paradigm that hydrogen sulfide and chloride are the ligands responsible for gold mobilization and precipitation by fluids across the lithosphere. Here we challenge this view by demonstrating, using in situ X-ray absorption spectroscopy and solubility measurements, coupled with molecular dynamics and thermodynamic simulations, that sulfur radical species, such as the trisulfur ion S−3, form very stable and soluble complexes with Au+ in aqueous solution at elevated temperatures (>250 °C) and pressures (>100 bar). These species enable extraction, transport, and focused precipitation of gold by sulfur-rich fluids 10–100 times more efficiently than sulfide and chloride only. As a result, S−3 exerts an important control on the source, concentration, and distribution of gold in its major economic deposits from magmatic, hydrothermal, and metamorphic settings. The growth and decay of S−3 during the fluid generation and evolution is one of the key factors that determine the fate of gold in the lithosphere.
© 2018 Science X Network 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. A view of the Campi Flegrei caldera from Posillipo hill. Credit: Francesca Forni Journal information: Science Advances Explore further Campi Flegrei volcano eruption possibly closer than thought More information: Francesca Forni et al. Long-term magmatic evolution reveals the beginning of a new caldera cycle at Campi Flegrei, Science Advances (2018). DOI: 10.1126/sciadv.aat9401 A team of researchers from ETH Zürich, Cardiff University, Istituto Nazionale di Geofisica e Vulcanologia and Sapienza-Università di Roma has found evidence that suggests Campi Flegrei could be re-entering a phase of pressure buildup. In their paper published in the journal Science Advances, the group describes their study of rock samples collected from the area and what they found. Citation: Study of rock samples suggests Campi Flegrei could be re-entering a new phase of pressure buildup (2018, November 15) retrieved 18 August 2019 from https://phys.org/news/2018-11-samples-campi-flegrei-re-entering-phase.html The Phlegraean Fields (part of which is known as Campi Flegrei) is an area located near the western coast of Italy that has a long volcanic history—there are 24 craters and other land shapes in the vicinity that have come about due to eruptions. The most recent eruption was not very violent but it did create a mountain in the area back in 1583—it has been named, Monte Nuovo. Notably, Campi Flegrei is also close to Naples—to the west. Vesuvius is to the east. In this new effort, the researchers have been studying rock samples collected in the area to learn more about the history of eruptions. By learning more about the conditions that lead up to eruptions, volcanologists hope one day to figure out how to predict eruptions.Prior research has shown that Campi Flegrei experienced two major eruptions over the past 60,000 years—one approximately 15,000 years ago, and one 39,000 years ago. Both have been described as cataclysmic, offering a hint of what might occur should the volcano erupt similarly today—the area is home to approximately 1.5 million people. There have also been numerous smaller eruptions. What they all have in common are changes to rocks, glass and minerals that are moved from underground to the surface by geologic forces. The researchers studied rocks known to have been blasted or forced from the ground due to multiple eruptions and then compared them to see if they could spot patterns.The researchers found evidence suggesting that Campi Flegrei might be entering a new phase of pressure buildup—one that could potentially precede an eruption. But they also note that they found no evidence that suggests the volcano might erupt any time soon. The type of build-up they describe occurs over hundreds or thousands of years.
At Rise Productions is back with its 12th stage production, Hors d’ oeuvres. Based on the unique concept of promoting one act plays. Hors d’ oeuvres has taken the onus of promoting talent. Hors d’ oeuvres 2012 was staged at Sri Ram centre and the theme last year was insecurity and was articulated with two humorous yet deep scripts. This year the theme has been picked to be bi-polar and includes a one fall on the ground, slap my face funny adaptation of the famous Broadway show The Foreigner by Larry Shue. And the other is a first of its kind self written horror script about a man’s interaction with heaven. Written and Directed by Archit Kumar, the cast includes Raghav Puri, Sanjana Chopra, Rahul Mudgal, Dhruv Raj Gupta, Ruchi Seth, Shivam Khanna, Namrata Bhatter, and Priya Mudgal.
The party season approaches as the mercury seems to be taking a breather. Adding to the ever expanding list of international DJs visiting the Capital gets one more name added. Here’s Martin Beltek Bijelic, better known simply as Beltek.In just a couple of years since he won Pete Tong’s competition with Copacabana, Beltek’s name regularly pops out on top of EDM music charts and labels such as Dim Mak, Ministry of Sound etc. His versatile production skills and fingerprint mass appealing sound already assured him remixing duties for major artists such as Faithless, Booka Shade, Gareth Emery and others. Also Read – ‘Playing Jojo was emotionally exhausting’In the city for his maiden tour by Kyoas Entertainment, Millennium Post catches up with the artiste. Read on. How do you like the music scene in India?Actually I was really happy to see that a lot of people here in India know my music. So as far as I saw the scene here, I like it big time. When did you start with this career? My career started with my first release, Copacabana on Chris Lake’s label Rising Music in 2008. And the main suspect to blame for my career start was Pete Tong. Since I won his music production contest Bedroom Bedlam back in 2007 with my track Copacabana. Also Read – Leslie doing new comedy special with NetflixHow has the journey been? Tell us about the best and the worst times so far…My journey was most of the time and still is very inspiring, joyful and positive for me. I think if you lose joy and inspiration for whatever is that you are doing, then you should definitely change your job. The only a bit not so cherished moments of my job are the flight and airport waiting moments. Those are the worst. What songs top your own playlist right now? Define your music philosophy for us Mike Hawkins, Pablo Oliveros – Bangover Jacob Plant – Fire and obviously some of my own.My music philosophy is simple – Like, Inhale, Connect and Party.
The six-day exhibition displaying the officers creative works ranging from figurative drawings, photographs capturing the reflections of the world to embroideries using pearls and bead sequins are on show at the Hudco Art Gallery. ‘This exhibition was impromptu. In fact, nobody in our office knew that we are into paintings and craftsmanship,’ said Nirmala Pillai, currently working in the Department of Telecommunications as Advisor. Pillai has painted acrylics of women. Also Read – ‘Playing Jojo was emotionally exhausting’‘I worked on acrylics. I like nature and many other small things which people ignore. I like to highlight them on my paintings,’ says Pillai who claims to be a self-taught artist.‘Painting is my passion…a strees-buster. I can give up anything for it,’ she says.Sumita Purkayastha, who works at the Department of Telecommunications as DG (NICF), has displayed her designs on saris, suits and dupattas in a combination of Mughal motif with material ranging from silk, tussar, crepes and cotton. Also Read – Leslie doing new comedy special with NetflixShowcasing her love for candle-making, Monali P Dhakate, currently on deputation to Staff Selection Commission as Regional Director, has exhibited her collection of handmade candles and chocolates, which she says she had picked up during her days in school.‘The love for candles started in my school days where we were taught of candle making. My mother used to call this craft as mess. She always says to create something exceptional…you need to focus on the smallest details. These words were inspirational for me. The passion and love for the craft developed with time,’ she says.Monali, has showcased her handmade candles for the first time in a public exhibition.‘The idea to exhibit our works was proposed by Nirmala. So we thought let’s come out and show the other side of us which is vibrant and colourful,’ adds Monali.Director (SEA) in the Department of Telecommunications, Yashashri Shukla’s passion for photography is evident with photographs on display at the exhibition giving glimpses of the places she has travelled over the years.The photographs of sunset at Chidiyatapu, Port Blair, a couple walking on the Radhanagar beach at Havelock, Tibetian flags and the ‘Bovine Spa’ are some of her favourite collections.
Contrary to popular assumption — and a talk by actor Arnold Schwarzenegger at the United Nations Paris Climate Change Conference — eating a vegetarian diet could contribute more to climate change than eating a non-vegetarian diet, warns a new study.Schwarzenegger, a former California governor, advised people to go meat-free one or two days a week to help protect the climate.But the new research found that consuming more fruits, vegetables, dairy and seafood is more harmful to the environment because those foods have relatively high resource uses and greenhouse gas (GHG) emissions per calorie. Also Read – ‘Playing Jojo was emotionally exhausting’“Eating lettuce is over three times worse in greenhouse gas emissions than eating bacon,” said one of the researchers Paul Fischbeck, professor at Carnegie Mellon University in the US.“Lots of common vegetables require more resources per calorie than you would think. Eggplant, celery and cucumbers look particularly bad when compared to pork or chicken,” Fischbeck said.The study measured the changes in energy use, blue water footprint and GHG emissions associated with US food consumption patterns. Also Read – Leslie doing new comedy special with NetflixThe researchers studied the food supply chain to determine how the obesity epidemic in the US is affecting the environment.Specifically, they examined how growing, processing and transporting food, food sales and service, and household storage and use take a toll on resources in the form of energy use, water use and GHG emissions. On the one hand, the results showed that getting our weight under control and eating fewer calories, has a positive effect on the environment and reduces energy use, water use and GHG emissions from the food supply chain by approximately nine per cent.However, eating the recommended “healthier” foods — a mix of fruits, vegetables, dairy and seafood — increased the environmental impact in all three categories — energy use went up by 38 per cent, water use by 10 per cent and GHG emissions by six per cent.The findings appeared in the journal Environment Systems and Decisions.
Holidays are happier in the beginning but soon turn out to be a boring routine for kids with each passing day. There are days when children would want to explore outdoor activities with friends; while there are others when they would just want to stay indoors. It is for the parents to ensure that their kids have a gala time during their vacation and simultaneously learn something productive.Keeping this in mind, Delhi Tourism has organised a Summer Craft Workshop in Dilli Haat, Janakpuri, for both children and adults which commenced on May 18 and will continue till June18. Also Read – ‘Playing Jojo was emotionally exhausting’ Pottery, tie and dye, madhubani paintings, clay work and paper craft are some of the creative activities organised by Dilli Haat and the list also has entertaining yet challenging activities like robotics, vedic maths. Observing the overwhelming response of the audience, the organisation has decided to add many more activities very soon.In the rush of tuition, school, hobby classes, there is no time left to do things that kids genuinely enjoy and in the process they don’t even get quality time with their parents. Also Read – Leslie doing new comedy special with NetflixDilli Haat encourages parents to turn up with their kids to the place so that they can have the fun of physical activities and explore their skills, creativity and other natural strengths unknown to them. These qualities only get highlighted when one take part in hands on activities that allow one to showcase their interests.So, get your kids outdoor this summer to experience the joy of learning crafts.When: June, 2016Where: Dilli HaatTimings: 11 am– 1 pm