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Ep. 555: Satellite Constellations and the Future of Astronomy

The other big issue at the AAS was the challenge that astronomy is going to face from all the new satellite constellations coming shortly. There are already 180 Starlinks in orbit, and thousands more are coming, not to mention the other constellations in the works. What will be the impact on astronomy, and what can we do about it?

Researchers flouting clinical reporting rules, and linking gut microbes to heart disease and diabetes

Though a law requiring clinical trial results reporting has been on the books for decades, many researchers have been slow to comply. Now, 2 years after the law was sharpened with higher penalties for noncompliance, investigative correspondent Charles Piller took a look at the results. He talks with host Sarah Crespi about the investigation and a surprising lack of compliance and enforcement. Also this week, Sarah talks with Brett Finlay, a microbiologist at the University Of British Columbia, Vancouver, about an Insight in this week’s issue that aims to connect the dots between noncommunicable diseases like heart disease, diabetes, and cancer and the microbes that live in our guts. Could these diseases actually spread through our microbiomes? This week’s episode was edited by Podigy. Listen to previous podcasts. About the Science Podcast Download a transcript (PDF). [Image: stu_spivack/Flickr; Music: Jeffrey Cook]

16 January 2020: Strange objects at the centre of the galaxy, and improving measurements of online activity

Strange objects at the centre of the galaxy, and improving measurements of online activity. For information regarding your data privacy, visit acast.com/privacy

Ep. 554: Big Telescope Controversy in Hawai'i

This week we're live at the American Astronomical Society's 235th meeting in Honolulu, Hawai'i. We learned about new planets, black holes and star formation, but the big issue hanging over the whole conference is the protests and politics over the new Thirty Meter Telescope due for construction on Mauna Kea.

Squeezing two people into an MRI machine, and deciding between what’s reasonable and what’s rational

Getting into an MRI machine can be a tight fit for just one person. Now, researchers interested in studying face-to-face interactions are attempting to squeeze a whole other person into the same tube, while taking functional MRI (fMRI) measurements. Staff Writer Kelly Servick joins host Sarah Crespi to talk about the kinds of questions simultaneous fMRIs might answer. Also this week, Sarah talks with Igor Grossman, director of the Wisdom and Culture Lab at the University of Waterloo, about his group’s Science Advances paper on public perceptions of the difference between something being rational and something being reasonable. This week’s episode was edited by Podigy. Read a transcript (PDF) Listen to previous podcasts. About the Science Podcast

09 January 2020: A look ahead at science in 2020

In this episode of the podcast, Nature reporter Davide Castelvecchi joins us to talk about the big science events to look out for in 2020. For information regarding your data privacy, visit acast.com/privacy

Areas to watch in 2020, and how carnivorous plants evolved impressive traps

We start our first episode of the new year looking at future trends in policy and research with host Joel Goldberg and several Science News writers. Jeffrey Mervis discusses upcoming policy changes, Kelly Servick gives a rundown of areas to watch in the life sciences, and Ann Gibbons talks about potential advances in ancient proteins and DNA. In research news, host Meagan Cantwell talks with Beatriz Pinto-Goncalves, a postdoctoral researcher at the John Innes Centre, about carnivorous plant traps. Through understanding the mechanisms that create these traps, Pinto-Goncalves and colleagues elucidate what this could mean for how they emerged in the evolutionary history of plants. This week’s episode was edited by Podigy. Ads on this week’s show: KiwiCo Download a transcript (PDF) Listen to previous podcasts. About the Science Podcast  

01 January 2020: Our reporters’ top picks of 2019

In this special round-up episode of the Nature Podcast, our reporters choose their favourite podcast piece of 2019. In this episode: 00:33 A sole sensation A study of people who do and don't wear shoes looks into whether calluses make feet less sensitive. Nature Podcast: 26 June 2019; Research article: Holowka et al.; News and Views: Your sensitive sole 08:56 The make up of the far side of the Moon Initial observations from the first lander to touch down on the far side of the Moon. Nature Podcast: 15 May 2019; Research article: Li et al. 15:43 Growth Mindset How a one hour course could improve academic achievement. Nature Podcast: 07 August 2019; Research article: Yeager et al. 27:44 ‘Manferences’ Nature investigates the prevalence of conferences where most of the speakers are male. Nature Podcast: 11 September 2019; News Feature: How to banish manels and manferences from scientific meetings 34:02 Q&A with Nobel Prize winner John Goodenough We talk to John Goodenough, who was jointly awarded the 2019 Nobel Prize in Chemistry for his role in the development of the lithium-ion battery. Podcast Extra: 09 October 2019 For information regarding your data privacy, visit acast.com/privacy

Ep. 553: What To Look Forward To In 2020

It's hard to believe it, but we survived another trip around the Sun. Now it's time to take the whole journey all over again, but with new news. Let's take a look at some of the space and astronomy stories we're looking forward to in 2020.

Nature PastCast, December 1920: The Quantum Theory

In this episode, we’re heading back to the early twentieth century, when physicists had become deeply entangled in the implications of the quantum theory. Was the world at its smallest scales continuous, or built of discrete units? It all began with Max Planck. His Nobel Prize was the subject of a Nature news article in 1920. In this episode, we’re heading back to the early twentieth century, when physicists had become deeply entangled in the implications of the quantum theory. Was the world at its smallest scales continuous, or built of discrete units? It all began with Max Planck. His Nobel Prize was the subject of a Nature news article in 1920. This episode was first broadcast in December 2013. From the archive Nature 16 December 1920 For information regarding your data privacy, visit acast.com/privacy

Basic Procedure and Cautions of Analog Circuit Design

An analog signal is an electrical signal that changes continuously. And analog circuit refers to a circuit used to transmit, transform, process, amplify, measure, and display analog signals, which are the basis of electronic circuits. They mainly include amplifier circuits, signal operation and processing circuits, oscillator circuits, modulation and demodulation circuits, and power supplies.

I Basic Procedure of Analog Circuit Design

1. System Definition

System definition is the basic premise of analog circuit design. According to the design requirements, the analog circuit design engineer needs to make corresponding function definitions for the circuit systems and subsystems, and determine the parameter range of related performances such as area and power consumption.

2. Circuit Design

The choice of circuit structure is an important part of circuit design. Analog circuit design engineers need to select the appropriate circuit structure according to the functional requirements, design specifications and corresponding parameter indicators that the analog circuit needs to implement, and then determine the combination of components.

For the design of analog electronic circuits, there is currently no mature design software available. Therefore, it can only be done manually by engineers based on their own experience. This increases the difficulty of analog circuit design to a certain extent and limits the development of analog circuits.

3. Circuit Simulation

Circuit simulation is an indispensable link in the design process of analog circuits, and it is an important basis for analog engineers to judge whether analog circuits can meet the design requirements.

The engineer continues to modify and adjust the circuit according to the simulation results until it can meet the given indicators and corresponding functional requirements. Commonly used methods are parameter scanning method, DC and AC analysis method, Monte Carlo analysis, etc.

4. Layout Implementation

The layout implementation is an important bridge for transforming circuit design into production. After the structure and related parameters of the analog circuit were determined from the previous design and simulation results, the design engineer described the physical and geometrical features of the designed analog circuit and converted it into graphic format to facilitate subsequent processing and production.

5. Physical Verification

During the physical verification phase, a design rule check (DRC) of the designed analog circuit is required. Design rule check is based on the given design rules to check the minimum line width, hole size, minimum pattern spacing and other limiting processes to measure the feasibility of layout process. In addition, the consistency of layout and circuit diagrams is checked. You can use the layout versus schematic (LVS) tool to extract the layout parameters and compare the obtained circuit diagram with the original circuit design diagram to ensure the consistency of the layout and the original circuit design.

6. Simulation after Extraction of Parasitic Parameters

The simulation of the circuit design before the layout is called "pre-simulation", and the "pre-simulation" is an ideal simulation without considering the parasitic parameters such as the resistance and capacitance of the wires. The circuit simulation performed after adding parasitic parameters to the layout is called "post-simulation". Only when the simulation results of the post-simulation meet the design specifications and system function requirements can the circuit design work be completed. The parasitic parameters have a great influence on the analog circuits. If the simulation results of the previous simulation are satisfied, the results of the post simulation may not meet the requirements. Therefore, design engineers need to continuously modify the transistor parameters based on the post-simulation results, and sometimes even adjust the circuit structure until the post-simulation results meet the system design requirements.

At present, the design of analog circuits is difficult and complicated, and the functions and system compatibility of the EDA tools are relatively backward. Besides, frequent manual intervention is required in the design process. These factors, to a certain extent, restrict the development of analog circuits.

 

II Cautions of Analog Circuit Design

1. In order to obtain a feedback circuit with good stability, it is usually required to use a small resistor or choking coil outside the feedback loop to provide a buffer for the capacitive load.

2. The integral feedback circuit usually needs a small resistor (approximately 560 ohms) in series with each integral capacitor larger than 10pF.

3. Do not use active circuits outside the feedback loop to filter or control the RF bandwidth of the EMC, instead, use only passive components (preferably RC circuits). The integral feedback method is effective only at frequencies where the open-loop gain of the op amp is greater than the closed-loop gain. At higher frequencies, the integrating circuit cannot control the frequency response.

4. In order to obtain a stable linear circuit, all connections must be protected withpassive filters or other suppression methods such as optical isolation.

5. Use EMC filters, and all IC-related filters should be connected to the local 0V reference plane.

6. The input and output filters should be placed at the connection of the external cables. Any connection ofthe wires inside the unshielded system needs to be filtered because of the antenna effect. In addition, filtering is also required at the wire connections inside the shielding system of a converter with digital signal processing or switch mode.

7. The powersupply of analog IC and ground reference pins require high-quality RF decoupling just like digital IC. However, analog IC usually requireslow-frequency power supply decoupling because the power supply noise rejection ratio (PSRR) of analog components increases very little when it’s above 1KHz. RC or LC filtering should be used on the analog power traces of each op amp, comparator, and data converter. The corner frequency of the power filter should compensate for the PSRR corner frequency and slope of the device to obtain the desired PSRR in the entire operating frequency range.

8. For high-speed analog signals, transmission line technology is very necessarybased on its connection length and the highest frequency of communication. Even for low-frequency signals, the use of transmission line technology can improve its anti-jammingperformance, but transmission lines that are not properly matched will produce antenna effects.

9. Avoid using high impedance inputs or outputsbecause theyare very sensitive to electric fields.

10. Since most of the radiation is generated by common-mode voltage and current, and most of the electromagnetic interference is caused by common-mode problems, using balanced transmit and receive (differential mode) technology in analog circuits will havea good EMC effect and can reduce crosstalk. The balanced circuit (differential circuit) driver does not use a 0V reference system as the return current loop, so it can avoid large current loops and reduce RF radiations.

11. The comparator must have positive feedback to preventincorrectoutput transitions due to noise and interference, and to prevent oscillation at the open-circuit contact. Don't use a comparator that is faster than needed speed(keep dV / dt within the required range, which is as low as possible).

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Related Source:

Introduction of Simple Analog Circuits

Reposted fromRachelAnne RachelAnne

Ep. 552: Boyajian's star (and other strange stars)

Huge surveys of the sky are finding more and more planets, stars and galaxies. But they're also turning up strange objects astronomers have never seen before, like Boyajian's star. Today we're going to talk about some unusual objects astronomers have discovered, and why this number is only going to go way way up.

Podcast Extra: From climate lawyer to climate activist

In this Podcast Extra, Nature's Chief Opinion Editor Sara Abdulla meets with Farhana Yamin to discuss why she ditched resolutions in favour of activism. This is an extended version of an interview originally broadcast in September. In this Podcast Extra, Nature's Chief Opinion Editor Sara Abdulla meets with Farhana to discuss why she ditched resolutions in favour of activism. This is an extended version of an interview originally broadcast in September. Comment: Why I broke the law for climate change For information regarding your data privacy, visit acast.com/privacy

CosmoQuest Hangoutathon Promo

Hi everyone, Producer Susie here. This weekend, December 21-23, 2019, we will be having our CosmoQuest Hangoutathon.  For 40 straight hours, our team will be bringing you guests, science and fun live on our channel. We are raising money to pay for our team to continue to bring you science, and for us to continue our citizen science programs, like the extremely successful Bennu Mappers from this past year, where over 3500 of you wonderful volunteers mapped over 14 million rocks on the asteroid Bennu, looking for a safe place for the OSIRIS-REx mission to grab samples to return to earth.  We want to keep doing projects like this - and we need your help to continue doing the science.  Please join us at starting 9am EST / 6am PST / 1400UTC. If you can’t tune in live, you can catch the replays on Twitch, and we’ll be trying our best to archive all of the content on YouTube after this weekend. We’re accepting donations at As part of the Planetary Science Institute, we are a 501c3 non-profit, so all of your donations are tax deductible where the law allows.  Please watch, share and donate if you can, so we can keep bringing the science to you! Thank you for listening!

Podcast Extra: Epigenetics

As part of Nature's 150th anniversary celebrations, Nick Howe dives into the topic of epigenetics. Since its origin in 1942, the term 'epigenetics' has been repeatedly defined and redefined. There's always been hype around the field, but what actually is epigenetics and how much does it influence our genes? In this Podcast Extra, Nick Howe speaks to Edith Heard, Director General of the EMBL, and Giacomo Cavalli, from the Institute of Human Genetics, to guide us through these questions and find out about the history and future of epigenetics. For information regarding your data privacy, visit acast.com/privacy

Breakthrough of the Year, our favorite online news stories, and the year in books

As the year comes to a close, we review the best science, the best stories, and the best books from 2019. Our end-of-the-year episode kicks off with Host Sarah Crespi and Online News Editor David Grimm talking about the top online stories on things like human self-domestication, the “wood wide web,” and more. News Editor Tim Appenzeller joins Sarah to discuss Science’s 2019 Breakthrough of the Year, some of the contenders for breakthrough, also known as runners-up, and a breakdown—when science and politics just didn’t seem to mix this year. Finally, Science books editor Valerie Thompson brings her favorites from the world of science-inflected media. She and Sarah talk about some of the best books reviewed in Science this year, a food extinction book we should have reviewed, a pair of science-centric films, and even an award-winning birding board game. For more science books, films, and games, visit the books et al blog at blogs.sciencemag.org/books. This week’s episode was edited by Podigy. Ads on this week’s show: Bayer; Lightstream; KiwiCo Listen to previous podcasts. About the Science Podcast

19 December 2019: A solution to the three-body problem, and festive fun

We’ve launched our 2019 listener survey. We want to know what you think of the show to help us make a great podcast. You can find the survey here. Thanks! This week, a solution to a centuries-old physics problem, and holiday shenanigans. In this episode: 00:51 Disentangling three bodies A problem that has stumped scientists since the 1600s has a probabilistic solution. Research Article: Stone and Leigh 08:50 Frosty the Snowman The first of our festive science songs, about how a certain snowman is faring under climate change. Scroll to the transcript section below for the lyrics. 11:00 Festive quiz show Our reporters battle it out to be crowned as this year’s quiz champion. Can they describe some of the top news headlines without saying certain important words? We find out. 19:21 Carol of M87 Our second song is about the Event Horizon Telescope collaboration’s imaging of the supermassive black hole at the centre of the M87 galaxy. Scroll to the transcript section below for the lyrics. 20:33 News Chat We hear about some of the people on Nature’s 10 this year. Feature: Nature’s 10: Ten people who mattered this year 30:00 Rockin’ Around Supremacy For our final song, we hark back to October, when Google claimed to have achieved quantum supremacy. Scroll to the transcript section below for the lyrics. TRANSCRIPT Frosty the Snowman lyrics: Frosty the Snowman was a jolly, happy soul But the smile wore off as the globe got hot ‘Cause the world used too much coal. Frosty the Snowman is a fairy tale they say He was made of snow But the kids won’t know ‘cause it’s them who have to pay. Gonna’ need some magic to Convince the world to stop ‘Cause now we’re running out of time And he’s feeling mighty hot. Oh, Frosty the Snowman, is endangered as could be And the children say they wish he’d stay, But they don’t trust you and me. He led them down the streets of town Right to the climate COP. They gathered there, and Greta stared And together hollered “STOP”. Frosty the Snowman, had to hurry on his way But he said we should do all that we could For to change our dirty ways. Frosty the Snowman, knew the time to act was now So the girls and boys said make some noise And we’ll get a change somehow Carol of M87 lyrics: Hark at the sound Photons abound Radio waves All seem to say Out in the dark This glowing spark We find our goal See a black hole. (M) M Eight-se’en (Eight) As it was then (tee) eons ago (se’en) See it aglow Data from these Observatries Processed to give The first image One seems to see With EHT Fire in a ring Light circling Einstein was right, Warped is the light, See the lensing Bending the ring. Now-we see-a supermassive black hole. (M – eigh-ty- se’en) How-we see-a supermassive black hole. (M – eigh-ty-se’en) (M) Space time is bent (Eight) See this event (tee) Horizon burn (ee) So much to learn (se’en) Out in the dark This glowing spark We find our goal See a black hole. Rockin’ Around Supremacy lyrics: Rockin’ around supremacy With the latest quantum chip Google says it won the race IBM says it’s a blip. Rockin’ around supremacy Would a regular PC Really take 1000 years? There’s no time to wait and see! You will get a futuristic feeling when you hear Voices raised in praise of physics Deck the halls with 54 qubits. Rockin’ around supremacy Is the hype just overblown? There’s more to do but either way It’s quantum milestone! You will get a futuristic feeling when you hear Voices raised in praise of physics Deck the halls with 54 qubits. Rockin’ around supremacy Is the hype just overblown? There’s more to do but either way It’s quantum mi-le-stone! For information regarding your data privacy, visit acast.com/privacy
Reposted by02mydafsoup-01 02mydafsoup-01

Ep. 551: Missing Epochs - Observing before the CMBR

The Cosmic Microwave Background Radiation is the earliest moment in the Universe that we can see with our telescopes, just a few hundred thousand years after the Big Bang itself. What will it take for us to be able to fill in the missing gap? To see closer to the beginning of time itself?
Reposted bysl420 sl420

Long Read Podcast: How to save coral reefs as the world warms

Research groups around the world are exploring new ways of protecting coral reefs from climate change. This is an audio version of our feature: These corals could survive climate change — and help save the world’s reefs. For information regarding your data privacy, visit acast.com/privacy
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