Author Topic: Episode #593  (Read 1959 times)

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Offline Ah.hell

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Re: Episode #593
« Reply #15 on: November 21, 2016, 10:25:40 AM »
Wiki says the NZ's electricity is 80% renewable, CIA says 29% from Fossil fuels, 55% hydro, and 16% other.  Which isn't surprising really, smallish population with lots of rough geography.  Hydro would seem obvious. 

Offline PsyStat

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Re: Episode #593
« Reply #16 on: November 21, 2016, 10:34:53 AM »
About the p-hacking email: several remarks for anyone wishing to go down that rabbit hole ...

1. In the larger realm of scientific misconduct, some of p-hacking's nearest kin are researcher degrees of freedom (addressed in earlier SGU episodes), HARKing, sigsearch, and data dredging.  As Steve suggested, some variants of these practices may be appropriate (e.g., with proper planning, interpretation, and reporting), but often they're not.

2. How to rigorously manage stopping early (e.g., based on planned "interim looks") in a trial falls under adaptive trial design, a major topic in the science of clinical trials.  Related to Cara's comment about "observational information first," these entail altering the trial based on what we've learned from its previous data.  Besides simply ending a trial early, other adaptive changes include adding or dropping an arm/group or modifying entry criteria or interventions.

3. Steve seemed to suggest that stopping early is largely a statistical matter, though he mentioned cost/risk criteria.  How this is handled varies, but in some (better?) trials an independent data monitoring committee (DMC) makes such decisions.  A DMC may include or use input from one or more statisticians (e.g., via the study's protocol or generic guidelines for trials) but tends to comprise experts in other relevant domains (e.g., focal medical/health topics, ethics).

4. Adaptive trial design relates to more broadly applicable stats problems in sequential analysis as well as value of information.  Both of these can be used to decide whether we have enough data about available options/actions to stop collecting more and choose an option.  For instance, sequential analysis, which may involves things like alpha-spending functions and monitoring boundaries, has historical roots in quality control (e.g., control charts for manufacturing processes) dating back to at least WWII.

5. Stopping early is linked to multiple comparisons, subgroup analyses, and outcome reporting bias, all of which Steve mentioned or alluded to, in that they involve the statistical notion of multiplicity: various ways to draw more than one "inference" (i.e., extrapolation from a data sample to its parent population/universe) from the same data set.  Experts disagree about whether or how to handle multiplicity, and it's one area where classical/frequentist strategies may differ markedly from Bayesian approaches.  To wit, Andrew Gelman's thoughts about multiple comparisons:

  http://andrewgelman.com/2014/10/14/one-lifes-horrible-ironies-wrote-paper-usually-dont-worry-multiple-comparisons-now-spend-lots-time-worrying-multiple-comparisons/

Offline lonely moa

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Re: Episode #593
« Reply #17 on: November 21, 2016, 12:27:50 PM »
... NZ is 95% renewables ...

That's great. I didn't know it. Details, please?

Depends on the wiki you look at, https://en.wikipedia.org/wiki/Renewable_electricity_in_New_Zealand, but if one thinks only of electricity generation and add the local (hydro) systems that aren't factored into the mix it's probably is nearly the 90%, Helen Clarke, goal.  Irrigation schemes in Canterbury, say, have been contributing to the mix since the 1930's (the RDR) and new ones are being addded with every scheme. 

Transpower (the publicly owned national power system) depends on transmitting power from the dams in Te Waipounamu (South Island) to itself and Te Ika-a-Maui (north island).  It uses DC current to decrease loss from the very South of the South Island to distribute it everywhere and buying electrons from homes costs it money.  Home generation is really only economic for the householder if the are off the grid (many rural dwellers do this) or concentrate power use during the day.  Our local provider buys power at less than 25% of what daytime power costs (half that for nighttime rates).

Oh, the geography doesn't lend itself to big hydro in Te Ika-a-Maui but they have all the hydrothermal.
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Offline daniel1948

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Re: Episode #593
« Reply #18 on: November 21, 2016, 06:11:09 PM »
... NZ is 95% renewables ...

That's great. I didn't know it. Details, please?

Depends on the wiki you look at, https://en.wikipedia.org/wiki/Renewable_electricity_in_New_Zealand, but if one thinks only of electricity generation and add the local (hydro) systems that aren't factored into the mix it's probably is nearly the 90%, Helen Clarke, goal.  Irrigation schemes in Canterbury, say, have been contributing to the mix since the 1930's (the RDR) and new ones are being addded with every scheme. 

Transpower (the publicly owned national power system) depends on transmitting power from the dams in Te Waipounamu (South Island) to itself and Te Ika-a-Maui (north island).  It uses DC current to decrease loss from the very South of the South Island to distribute it everywhere and buying electrons from homes costs it money.  Home generation is really only economic for the householder if the are off the grid (many rural dwellers do this) or concentrate power use during the day.  Our local provider buys power at less than 25% of what daytime power costs (half that for nighttime rates).

Oh, the geography doesn't lend itself to big hydro in Te Ika-a-Maui but they have all the hydrothermal.

Thanks for the info. But I thought DC power transmission was only suitable over short distances. Isn't that why AC has become the standard?
Daniel
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Offline lonely moa

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Re: Episode #593
« Reply #19 on: November 21, 2016, 09:27:47 PM »
... NZ is 95% renewables ...

That's great. I didn't know it. Details, please?

Depends on the wiki you look at, https://en.wikipedia.org/wiki/Renewable_electricity_in_New_Zealand, but if one thinks only of electricity generation and add the local (hydro) systems that aren't factored into the mix it's probably is nearly the 90%, Helen Clarke, goal.  Irrigation schemes in Canterbury, say, have been contributing to the mix since the 1930's (the RDR) and new ones are being addded with every scheme. 

Transpower (the publicly owned national power system) depends on transmitting power from the dams in Te Waipounamu (South Island) to itself and Te Ika-a-Maui (north island).  It uses DC current to decrease loss from the very South of the South Island to distribute it everywhere and buying electrons from homes costs it money.  Home generation is really only economic for the householder if the are off the grid (many rural dwellers do this) or concentrate power use during the day.  Our local provider buys power at less than 25% of what daytime power costs (half that for nighttime rates).

Oh, the geography doesn't lend itself to big hydro in Te Ika-a-Maui but they have all the hydrothermal.

Thanks for the info. But I thought DC power transmission was only suitable over short distances. Isn't that why AC has become the standard?

... in the USA

https://www.quora.com/When-and-why-is-DC-used-instead-of-AC-for-long-distance-electric-power-lines

https://en.wikipedia.org/wiki/List_of_HVDC_projects

https://en.wikipedia.org/wiki/War_of_Currents

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Offline amysrevenge

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Re: Episode #593
« Reply #20 on: November 22, 2016, 10:57:27 AM »
The big reasons are DC bypassing synchronicity requirements, the difference between peak and RMS current for AC, skin effect for AC, and you need 2 less wires for DC.
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Re: Episode #593
« Reply #21 on: November 22, 2016, 11:41:25 AM »
My understanding is that AC is still more cost-effective for distribution because it can be distributed at a higher voltage and stepped down at each end point using a simple transformer, something that cannot be accomplished with DC due to the higher cost and complexity of DC voltage conversion equipment.  As one increases distance and voltage, the losses of AC eventually outweigh the upfront costs of DC conversion, such that for transmission there's a break-even point above which DC is definitely the superior choice.
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Offline Ah.hell

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Re: Episode #593
« Reply #22 on: November 22, 2016, 11:48:10 AM »
We've definitely had this conversation before.  IIRC, DC is used for certain high capacity long distance transmission lines or to act as cross ties between grids but not much beyond that.  Something about increased efficiency at high power and easy of converting between grids that aren't synchornized, converting 50hz to 60hs for instance.  ETA, actually seems to be more for connecting asynchronus grids at the same frequency.

https://en.wikipedia.org/wiki/High-voltage_direct_current
« Last Edit: November 22, 2016, 11:51:20 AM by Ah.hell »

Offline AndrewzC

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Re: Episode #593
« Reply #23 on: November 23, 2016, 05:49:42 AM »
Meanwhile, the rest of the world is discussing the most incredibly ginormous news story and its relevance to skepticism, science, critical thinking, and the future of civilisation. That big orange elephant in the room.
Sorry. But thats how I see it.

I posted earlier in the science forum about Trump scrapping NASA's climate research and threatening all 'politicised' research (i.e. any research he and his team don't like because it isn't aligned with his politics). Perhaps the rogues will only discuss issues like this after decisions have been implemented and funding has been pulled. Which is, of course, too late.

https://www.theguardian.com/environment/2016/nov/22/nasa-earth-donald-trump-eliminate-climate-change-research

Online Andrew Clunn

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Re: Episode #593
« Reply #24 on: November 23, 2016, 10:11:50 AM »
It was perhaps too late as of November 9th.

Offline smudge

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Re: Episode #593
« Reply #25 on: November 27, 2016, 08:18:19 AM »
It was perhaps too late as of November 9th.

Nope.
We keep on making the arguments and promoting evidence based policies, right?
In the same way we would if a homeopathy nut were put in charge of a health authority. In the same way we would if an astrologer was put in charge of an effin' sharp stick. Thats the entire point of skepticism, surely? We argue against this sh*t. Whenever and wherever anti science, anti evidence, and flawed logic is to be found.

Hence my serious frustration with the SGU crew over Trump. The stated position makes no sense. It is counter productive. It is self destructive. It contradicts their stated mission. It's just.....BS.
And yes, it pains me to say that. But if skeptics stand for ANYTHING it is for calling out BS WHEREVER we see it. ESPECIALLY in our own movement. ESPECIALLY when it comes from those we admire.
Not to do so is cowardly. Its not skepticism. Its group think. It's bowing to authority in the form of hero's. Its not what skeptics do.



« Last Edit: November 27, 2016, 08:21:02 AM by smudge »

Offline AndrewzC

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Re: Episode #593
« Reply #26 on: November 27, 2016, 04:05:57 PM »
I hope they're staying schtum on Trump because he isn't President yet, even though his 100 day plan and emerging cabinet appointments are horrific from the point of view of the skeptical community. I fear that rogues' desire to remain apolitical is going to kill the SGU. Surely they'll have to respond.

Offline daniel1948

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Re: Episode #593
« Reply #27 on: November 27, 2016, 07:26:10 PM »
I hope they're staying schtum on Trump because he isn't President yet, even though his 100 day plan and emerging cabinet appointments are horrific from the point of view of the skeptical community. I fear that rogues' desire to remain apolitical is going to kill the SGU. Surely they'll have to respond.

I don't think it will kill the SGU, but I do think it is a mistake. However, I can understand it. Trump has shown himself to be so vindictive and so litigious that they might be genuinely afraid of calling him out. They fought off the lawsuit from that scam artist only with difficulty. If Trump decided to get serious about going after them, they would be ruined. They may just be too visible to risk taking him on directly. Easier to talk about the bad policy decisions that are sure to come.

I'm disappointed they are not calling him out. But I cannot fault them for trying to stay below the radar.
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Online lubbarin

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Re: Episode #593
« Reply #28 on: November 27, 2016, 07:37:02 PM »
Me in 3 1/2 years
(Reading yet another story on the corrupt multi-billion dollar boondoggle of the Trump Resort hosted Sochi style Olympic games, huddled behind a dumpster)
"If only the SGU had called Trump a pos..."
I am in favor of killing all whales on principle. Where is my avalanche of 'provocateur' money?

Online werecow

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Re: Episode #593
« Reply #29 on: November 27, 2016, 07:57:04 PM »
I hope they're staying schtum on Trump because he isn't President yet, even though his 100 day plan and emerging cabinet appointments are horrific from the point of view of the skeptical community. I fear that rogues' desire to remain apolitical is going to kill the SGU. Surely they'll have to respond.

I don't think it will kill the SGU, but I do think it is a mistake. However, I can understand it. Trump has shown himself to be so vindictive and so litigious that they might be genuinely afraid of calling him out. They fought off the lawsuit from that scam artist only with difficulty. If Trump decided to get serious about going after them, they would be ruined. They may just be too visible to risk taking him on directly. Easier to talk about the bad policy decisions that are sure to come.

I'm disappointed they are not calling him out. But I cannot fault them for trying to stay below the radar.

Me in 3 1/2 years
(Reading yet another story on the corrupt multi-billion dollar boondoggle of the Trump Resort hosted Sochi style Olympic games, huddled behind a dumpster)
"If only the SGU had called Trump a pos..."

Yeah, some perspective is in order here... I'm sure I made it very clear in the #592 thread that I was annoyed that they barely discussed the elections and what came after, but I doubt that it would have actually changed anything significant on a societal scale if they had, since most of the people listening to the SGU probably already agree with them on most of the issues related to science and skepticism. And given that a lot of people felt that not discussing the elections was a good thing, I highly doubt it will kill the SGU (and there is plenty of reason to keep listening to the podcast). I also have little doubt that they'll discuss the relevant things like policy related to climate change or vaccinations or what have you as they occur.

(I also highly doubt that they're not discussing it because Trump might sue them, but in fairness, I'm not a very good mind reader.)
Mooohn!

 

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