Open Thread Feb 16 - Feb 23, 2016

Clarity's bitching and moaning containment comment

No other top level comment by Clarity will be made in this Open Thread will be made because a considerable portion of LW voters don't give a shit

1. Windows 7 phones are problematic

There is currently no way to remove the auto-fill terms you have accumulated over time asides from hard reseting the phone.

-Windows 7 phone search history can't be deleted...

Seriously, Microsoft? People could find I eschew porn to instead listen to songs that remix in or mashup sounds from porn while going about my daily activities.

2. Can your genes exempt you from an altruistic imperative to donate your organs?

Do our SNP's indicate any exceptions to the duty to donate one's organs? rs17319721(A)'s and Rs429... are associated with kidney related issues. It doesn't appear any others are known to. The implications are unclear.

3. El Chapo's getting desperate.

What would you do in his situation? How does me manage to get to cartel to do his bidding when he's on the run when they could usurp him instead? I assume that other high up Sinoloa cartel people just appreciate his intelligence in planning their operations. And, that incidental helpers opportunistically solicit his favour, bribes and fear his influence without actively making them because of his reputation. Maybe there are some interesting mechanisms in there too, like people he's earmarked as having to die if he is ever caught, or doesn't escape by a certain time, or dies*, like a kind of prediction market. I would imagine such criminals have sophisticated prediction market-esque trustless systems to protect them. I mean, I wouldn't otherwise count on the loyalty or trustworthiness of other criminals...I mean, it would be a lot harder to replicate his actions in more Western countries because of greater structural integrity of social institutions and norms, but I can't help but be in awe of the guy's intelligence and ruthless pursuit of his ends and means.

4. Interesting takeaways from Tim Ferriss’s productivity interview of a former four star US special forces and joint coalition forces general

• High peer ratings have the highest predictive validity for top-level military leadership appointments and advancement

• After ww2 they asked combat organisations what was most useful from their training and people said: distance running and pack marches (explained as: because it pushed them) and live fire exercises (he adds, dealing with uncertainty too but that wasn't found from the ww2 survey). I noted that this was said around 48 mins 40 seconds in.

• watch 3 people - someone senior who you admire, a peer who is doing what you are doing better than you and someone junior who is doing the job you were doing better than you did

5. My sister is such c-word

I wish there were psychologist/therapist gift vouchers for frenemies or people you have to stay in contact with for a long time due to work or familial obligation...

6. Karma pattern analysis

a graph of my karma: Increasingly volatility and controversiality (high scores and low scores). Seems to be alternating clusters of high and low karma. Is that attributable to global variation in sentiment of lesswrong voters or to temporal variation in the karma attractiveness of my posts?

7. Why is psychiatry so weird?

• What accounts for the discrepancy between reports of suffering by the mentally and neurologically ill, and the sympathy afforded to them? Do estimates for disability or quality of life by mental health patients systematically deviate from observer or physiologically revealed estimates? How about addicts or pain patients?

• Smoking and schizphrenia confounded by weight control beliefs? If so sz without antipsychotic would smoke less

8. How am I supposed to follow the law if I don't know what the law is?

The AI control problem is a principal-agent problem, just like theattorney problem. Thoughts on radically simplifying the law to re-emphasise personal responsibility, promote leadership against paralysis and law anxiety?

9. How’s democratic information asymmetry working out?

Not too bad.

Ballot papers present a handful of names, a handful of labels and voting process ensues. Why aren’t there more random incompetents elected to public office? This is not to say that they aren’t there, but this system of appearingly intense information asymmetry seems to work out okay.

To be an independent candidate requires lots of voters to nominate you and therefore substantive mass (even if minority(appeal), to be a party candidate requires winning an internal preselection election (by people who tend to vote for people they have existing, long standing elections with) and to win council generally requires a racially appropriate name for the area’s demographic who are like to know you.

This screening process may separate the wheat from the chaff early-on.

10. A movie about an internet drug dealer from da hood gives a lesson in enthusiastic consent

"I'm bored as fuck, how about we play? Lets play mother may I. Do you remember how to play that?... May I take off my clothes?... May I walk over to you?... May I touch you?"

-Female character from Dope (2016 the movie)

I've omitted the guys response since they were more or less 'yes'.

What great, playful elicitation of enthusiastic consent without an awkward, forward question!

11. Fallacy charlatans

Brendan Moynihan, who the author of the Black Swan said wasn't a charlattan unlike most finance book authors, summarises market participation fallacies as internalising what should be external events here onwards. His thesis perplexis me. It's doesn't seem wrong, it seems wronger than wronger, but his case seems very compelling. I smell some darks arts. I wonder if the Black Swan author spoke too soon...

12. 80K for LMIC's

I wrote a haiku:

Teaching to earn

To earn to give

80,000 Hours 2020

Bridging 80,000 Hours with developing world education will kill 3 birds with one stone: earning to give, developing world education and the problem of bridging between schooling and economic opportunity.

13. EA unicode symbol?

How about 'æ'?

14. Is pedo advocacy an undervalued, neglected social cause?

My heart continues to bleed for virtuous pedophiles and the ostracisation that probably encourages surrepticious, unhealthy sexual and romantic relationships between adults and children. I hope more people will pledge public support for groups trying to fight to treat pedos like people. There seem to be advocacy organisations that are above board and I wouldn't be suprised if an increasingly sex positive future society crowns pedo advocates of today with the glory affored to early LGBTI campaigners. Maybe they'll call them LGBTIP one day. I feel ashamed that I should have to disclaim that I am not at all attracted to children (and barely have a sex drive nowadays in general) in order to give extra credibility to this post. I'm also ashamed that when I'm in IRL company I'm given to joining in the group emotion and condemning pedos when the topic comes up, but at least I'm willing to talk about it more uh 'rationally' here.

15. Siblings of low-functioning autistics can have a lot of carer responsibilities. Do they deserve the baggage of carrier stigma too?

Based on the Wikipedia article on the heritability of autism I have concluded that if you're dating someone who has a sibling that is autistic, other than caring for their sibling you should consider having kids early if you intend to, not having kids if the mother has a psychiatric illness but otherwise no worrying too much about passing on the autism. The rate of autism in the general population is 1.47 percent. Prevalence of autism in siblings of autistic children was found to be 1.76% in 2005 Danish study looked at "data from the Danish Psychiatric Central Register and the Danish Civil Registration System.

The risk was twice as high if the mother had been diagnosed with a psychiatric disorder. The study also found that "the risk of autism was associated with increasing degree of urbanisation of the child's place of birth and with increasing paternal, but not maternal, age.

However, less authoritative (yahoo answers) sources suggests that the specific etyiology of the autism may affect the chance of inheritence. Allegedly if the autistic family carries fragile X then the chance of inheritence is like 10 percent plus or something. They recommended talking to a genetic counsellor so I reckon the best steps are to do that, or do more thorough research than I've done here about where autism has occured in your mate's family!

I've created a cost-benefit analysis of embryo selection for intelligence: http://www.gwern.net/Embryo%20selection

Turns out to be fairly challenging but ultimately delivers sensible results: modestly profitable but nothing special at current prices/polygenic-scores. But things get more interesting once we get scores from n>360k studies, and the multi-generational consequences are very interesting if we can get boosts like +9 points. Of course, it's mostly all a moot point and academic because of...

CRISPR. I've had a hard time getting prices because they all sound too good to be true.

Rationality for managers, part 374:

If your plans are greater than your capacity to do stuff, you need to set priorities. Prioritizing is a way to achieve some of your goals sooner, at the cost of achieving some other goals later (or not at all). Prioritizing is not a magical tool to achieve all of your goals sooner. If you cannot make an explicit decision to postpone some goals, by definition you are unable to set priorities.

Adding the words "priority: urgent" to a task achieves the desired effect only if there are other tasks without the label "priority: urgent". Giving the label to all your tasks is equivalent to giving it to none of them. For example, if you create a planning spreadsheet or configure a planning software with priorities from 1 (highest) to 5 (lowest) only to find later that each task is assigned a priority 1, then the truth is that your company or division does not have priorities.

Even if you use different priorities, but the tasks labeled "priority: urgent" exceed your capacity to do stuff, then effectively every other label becomes synonymous to "this will never be done", and the label "priority: urgent" itself will mean "this should be done, but we are unable to set priorities for the stuff that should be done". For example, if your priorities are from 1 (highest) to 5 (lowest), but the number of tasks with priority 1 exceeds the capacity of your team, then the tasks with priority 2 will never get done, despite the impression that the number 2 seems better than average on the scale from 1 to 5. And you still have not set priorities within the set of tasks that have priority 1.

Exercise 1: Your team has two employees, each of them working 8 hours a day. To meet the deadline, you would need on average 24 man-hours of work done each remaining day. Instead of hiring another employee, your colleague in management suggests that it would be better to spend that money instead to pay an external company to install an intranet website where managers will be able to assign a priority to each task. Your colleague shows you a research suggesting that tasks with higher priority statistically get completed sooner than tasks with lower priority. Thus, setting a high priority to all your tasks should solve the problem with the deadline. What could possibly go wrong?

Exercise 2: You have an employee working 8 hours a day on an important continuous task that requires 8 hours of their time every day. There is another, less urgent task that needs to be done, that requires only 20 hours of work, once. You assign the second task to the same employee, but specify that this task has lower priority than the original task, because if the original task gets behind the schedule, there would be bad consequences for the company, and then also for the given employee. How many days on average will it take the employee to complete the second task?

I have 90% credence that Old_Gold is the new account of Eugine.

If we would apply Elon Musk first principle thinking to the problem of building homes in which we live, how would we build homes? Are there any big companies taken up that challenge?

Top rated questions on the new prediction website metaculus:

Fully autonomous self-driving cars by 2018?
Will "Planet Nine" be discovered in 2016?
In 2016, will an AI player beat a professionally ranked human in the ancient game of Go?
Will the cost of sequencing a human genome fall below $500 by mid 2016?
Experimental tests of quantum effects in cognition?

R> genome <- c(9408739,9047003,8927342,7147571,3063820,1352982,752080,342502,232735,154714,108065,70333,46774,
              31512,31125,29092,20963,16712,10497,7743,7666,5901,5985,6618,5671,5826,5550,5096,4008,4920,4905,
              5731,3970,4211,1363,1245,1000)
R> l <- lm(log(I(tail(genome, 3))) ~ I(1:3)); l
# ...Coefficients:
# (Intercept)       I(1:3)  
#  7.3937180   -0.1548441  
R> exp(sapply(1:10, function(t) { 7.3937180 + -0.1548441*t } ))
# [1] 1392.5249652 1192.7654529 1021.6617017  875.1030055  749.5683444  642.0417932  549.9400652
# [8]  471.0504496  403.4776517  345.5982592

Sorry if this is a stupid question *, but is there any not complicated literature about how mass point geometry is related to, or used to teach more efficiently, or something else, probability theory? I used to fantasize about going through a middle-highschool-level book on MPG with my middle-highschool pupils (with added benefits of reinforcing Newtonian mechanics), and to get them into Bayes law (probability masses as masses and odds as lengths:), but... It was hard to imagine, say, triangles formed by probabilities.

I Googled it up, didn't find "exactly the thing" and moved on.

• and on the similar note, do we still have them?

What are the best public places to discuss existential risks?

My list in order of quality:

Useful:

Lesswrong.com

https://www.facebook.com/groups/ExistentialRisk/

Semi useful:

http://www.longecity.org/forum/forum/360-risks-survival/

https://www.facebook.com/groups/lifeboatfoundation

http://effective-altruism.com/r/main/

Almost dead now:

Lifeboat foundation mailing list - almost dead now, but had good discussions before

http://www.forumlog.com/nanobiotechnologyspace/index.php

https://www.reddit.com/r/ExistentialRisk/

Special:

http://forum.arctic-sea-ice.net/index.php/board,25.0.html

flutrackers.com

Is there a term for a generalization of existential risk that includes the extinction of alien intelligences or the drastic decrease of their potential? Existential risk, that is, the extinction of Earth-originating intelligent life or the drastic decrease of its potential, does not sound nearly as harmful if there are alien civilizations that become sufficiently advanced in place of Earth-originating life. However, an existential risk sounds far more harmful if it compromises all intelligent life in the universe, or if there is no other intelligent life in the universe to begin with. Perhaps this would make physics experiments more concerning than other existential risks, as even if their chance of causing the extincion of Earth-originating life is much smaller than other existential risks, their chance of eliminating all life in the universe may be higher.

Decision theory humor, if anyone wants to contribute: https://www.reddit.com/r/DecisionTheory/comments/46ndc0/decision_theory_humor/

Events of recent days have made me suspect that I feel less depressed on days when I have little or no beard. But now that I know this hypothesis, I don't know how to test it without priming myself every time I shave. Suggestions?

[Comment removed because it drew attention to links between online identities of someone who turns out not to want attention drawn to them.]

Prediction Markets Going Wrong?

How many ways are there for a prediction market to go wrong?

In my story's current draft, once my protagonist upload has made a few copies of himself, I have him start up a prediction market to try to improve his decision-making, such as the likelihood any given plan will reach a useful goal. (Using currency created ab nihilo via a Bitcoin-like blockchain.) I have his similar copies end up coming to an overconfident consensus, leading to an explosive disaster, leading to attempts to deliberately diversity his copies' mindstates. Initially by simple psychological priming, later by more potentially dubious experimentation.

I only have an interested amateur's understanding of prediction markets, and have nearly no conception of the complications involved, such as what design choices are available when founding one or how many ways one can go wrong (other than the particular item in the previous paragraph). If there's anything you'd like to see in a story with a prediction market, or if you have any advice or references I can read up on, I'd appreciate your input.

(The idea I'm currently pondering: if it would be feasible to use a prediction market to generate answers to the question, "Which rights (or 'rights') should we include in our constitutional Bill of Rights, and which should we leave out?")

I've been reading HPMOR for the past week (currently at TSPE aftermath) and I'd like to recommend it to anyone who hasn't read it yet.

How good is the case for supplementing Vitamin K2 along with Vitamin D3?

What might be the cause of the perceived difference between the atheists/nontheists in Europe and in the USA?

I have the general feeling that the average atheist in the USA, when asked about religion, will be very open about believing religion to be either evil or ridiculously stupid, and will make at least a few remarks about how idiot those lunatics must be who believe that there are invisible people living on the top of the clouds. On the other hand, in Europe you are more likely to hear that "well, I'm not very religious", but many would culturally still identify as a Christian, and will held marriages, child naming ceremonies, funerals etc. in a church, and might even rarely, but occasionally go to church on a bigger festival (like Christmas) because it looks or feels nice.

I wonder why. I know much more Europeans than Americans, so it might be that the louder voices are better heard from a group I have less contact with, or it might be that because in the USA the Christian fundamentalists are louder than in Europe, so the atheist fundamentalists are also louder.

I'm fully aware that I based this observation mostly on people I have contact with, and in at least a small part being influenced by popular culture, but I don't know of any exhaustive research or survey comparing the cultural standpoint of nontheists specifically regarding the differences between Europe and the USA.

containment thread 2

1. Manipulating financial markets for fun and profit

While emerging market regulators have not identified specific skills sets required of surveillance staff, survey results highlight that the common skills that regulators and exchanges seek in surveillance analysts include data mining and analytical skills and the ability to understand the mechanics of the electronic trading environment, i.e. trade flow and processes and to analyse and evaluate surveillance technology programs and procedures. In addition, maintaining a good contact of networks with the industry in order to draw leads of potential market abuse and facilitate the understanding of market trends and market behaviour is a critical aspect to supplement surveillance efforts.

-Approaches to market surveillance in developing markets by the International Organization of Securities Commissions (IOSCO) who are practically begging for regulatory capture. Wanna fuck a wealthy investor? Become a regulator!

IOSCO explicitly outlines their recommended investigatory methodology in market manipulation from pg. 12 onwards. This allows for stealth adaptations, and since they also describe their recommended approach to prosecution, dodging the po-lice. Thanks for the how-to guide IOSCO. Oh, did I mention a document on specific technological limitations to policing this kind of thing? Anyone want to rob a banking system?

According to the Australian regulation:

The Market Integrity Enforcement team typically had over 85 matters under investigation at any one time during the relevant period

-report

yet only 3 insider trading, 2 market manipulation, 8 infringment and 2 pecuniary penalty actions where taken overall (table 1). Table 3 shows that 122 inquiries where made into suspicious behaviour. That's a lot of false positives. And this is all really basic stuff. Even batman villain Bane could think of something creative like a terror attack against a stock market to capitalise on it (his client shorted first, presumably). Of course, this doesn't work IRL because terrorists attacks even on the exchange tends to have a rather innocuous short-lived effect, with exceptions like 911. However, an attack on a particular company might be very different.

Insider trading surveillance basically hinges on big money trades (and that's big money from the perspective of hedge funds...) that are subsequently investigated. If you're a regular joe and your friend billy works at the listed company in quesiton and leaks some reliable, market sensitive info to you, you basically get some big wins, pre-empting the market, scot free. What suprises me then is that this not-insignificant profit opportunity doesn't have a bottom-up criminal infrastructure. Where are teh darkweb forums for this kind of deals! Where the stories of shady dealings by your friend Pete! In the meantime, I gotta make me some friends in some listed companies....maybe some biotech peeps working in R&D...

Are 'anonymous' smart contracts, known only by the parties involved plausible? Should they be functional, I envision that insider trading will being unregulatable if conducting via darknet anonymous smartcontracts. Someone could set up a tor site that connects scientists with financiers who then formulate an anonymous smartcontract that binds that scientists to lose $100,000 if the value of a stock is lower after new years day, since the scientist has told the financer (before it has become public knowledge) that the company will announce that they have been granted FDA approval for a drug, or something like that on Christmas. However, if the stock price rises by a threshold amount, they are to receive $1million from the financier. Meanwhile, the financier will invest $2M in the stock and expect an appreciation greater than the amount he will reward the scientist with for his trust. Too easy.

2. Tobacco control undervalued as an opportunity to give?: Only for heretical strands of EA

Tobacco control is undervalued if:

• you are a total utilitarian, rather than favouring the personal-affecting view, since the mortality is humongous for smoking

• you don't factor in 'justice' considerations, where you believe 'choice' to start smoking in spite of public health recommendations should be punished with less altruism than otherwise

• you don't believe GiveWell donors will pay proportional multiplayer game theoretic attention to Development Media International, a standout charity that doesn't make the top 4 cut and promotes avoidance of smoking among other things

• you give extra value to local problems (e.g. for tractability or sustainability reasons), since smoking is a big issue in the developed world too (unlike deworming)

3. Amateur intelligence analysis

Is there a credible risk that terror attacks on underground storm water drains could bring down buildings, or otherwise causing mass casualties (such as by some consequence to critical drainage infrastructure)? Cross posted at: /r/credibledefence

4. The relative value of contributing to LW vs Wikipedia

Would the time you spent posting here in LessWrong have been better spent posting on Wikipedia?

Okay, stupid and off-topic question:

I want to get a tablet for a Small Child so she doesn't keep bugging me for mine. The one I got her for her birthday broke in an unexpected manner: The glass is not damaged but the screen is displaying black lines and similar garbage. (It was also working at the beginning of a car ride and failed at the end of it - it couldn't have fallen onto a hard surface.) So I'm looking for a tablet that 1) has access to the apps on the Google Play store I've already bought for her; 2) can survive a tumble down a flight of stairs or being thrown onto uneven asphalt and 3) is as cheap as possible while still meeting criteria 1 and 2. Suggestions?

(She's managed to crack the glass on my iPad once - an iPad without a rugged case is not sturdy enough to survive the abuse I expect this thing to have to take.)

Marriage: Civilization's BIggest Mistake

Something that bothers me about this is the all-too-common idea that kids are unruly and will cause endless destruction. I remember my parents being anxious to leave me alone at home and me thinking "Umm what? What could I do?" and being proud the house didn't look like whatever's left after a direct hit from a nuke.

Why's that?

Anyone have recommendations of fiction along the lines of Worm and HPMOR that are also very long (>400k words)?

Did someone change the threshold for hiding comments? Didn't it use to be that -4 comments were hidden and now -3 are?

Miniature brains seem like they could become very important.

Can they be kept alive for long? Can they be enlarged? Can they be trained? Is the distinction between human neurons and other mammalian neurons significant?

To prompt some discussion, say someone tried to build "self-driving" cars in the following way: put a big brain full of rat neurons in a vat, hook it up to a car, and then train it to navigate.

How would a Donald Trump presidency effect the probability we achieve friendly AI before Clippy arrives?

Also, it appears OP used Comic Sans. Hm.

Why I don’t want to explore storm water drains

*Or, terrifying excerpts from a how-to guide on exploring drains

If there is a protruding wall and you can't get up a shaft in time, get in close to the downstream side of that wall. This is not very safe but it is better than standing in the path of the oncoming maelstrom. Hanging from a grille is not so good either, you will be dumped on (and may lose your grip) but that might be better than being flushed a few km at high speed. Staying out of the flow is mega-priority... nothing can ruin your day like a derilect lawnmower in the back of the head, and there are nastier things in the feeder canals than old 44 gallon drums; roofing beams, bits of rail track, shopping trolleys. The flow smashes them all along, and they are bad news.

Emergency escape tacticsFirst thing to do is keep cool and rational, don't panic. You are in control. Then leave in a hurry. What if you're 2km from the entrance? Well, use your brain. Water heads for the lowest point... so go to the nearest, preferably downstream manhole shaft and climb up it, and wait for the flood to scream by below you. You need not pop the cover, just stay in the shaft, and climb higher than any `bathtub ring' of polystyrene balls and dead grass you see on the shaft wall. Be warned, you may be up there a long time before the raging torrent desists. It will be loud and frightening, but breathe calmly, conserve your airspace.

Ok, so you're up a drain and notice the side tunnel flow increasing a bit. Check the water. Is it dirty? Is it oily? If yes, it is likely to be raining and you're in something far worse than deep shit if you don't do something about it.

Pay attention to what's going onThings to notice when a drain is filling up: the air currents change, as does the noise level. A quiet drain soon gets noisy as the side tunnels and drop junctions start dumping into the main canal. When lots of water goes into a drain, the air is displaced, and you notice big gusts of wind... this is particularly true if the roads were hot when the rain landed on them; the warm water goes into the drain, heats the air above it, which expands, pushing cold air out in front of it.

Rain and the legendary flash floodThe media and authorities point to the alliterative "flash flood' phenomenon quite a lot. Flash flooding - flooding without warning - is bullshit. It does NOT happen. You have between two and four minutes to get out, up a shaft or on a high ledge before the system is primed... IF you know how to read the signals and don't mess about getting to high ground. You can generally tell if the drain you're in has ever flooded to the top, look for polystyrene bits stuck to the roof or bits of plastic and stick protruding from high stepirons or joints in the pipe or walls.

In theory one could conceivably get anything from a sewage overflow into a drain. Cuts are common when one falls over, and people have occasionally ingested runoff unintentionally. VERY nasty things are more common in sewers than stormwater: Leptospirosis, for instance, is contractable via the skin, and can live for 3 weeks in fresh water (but is killed relatively quickly in salt water). Leptospiria icterohaemorragiae, the causative agent, will kill you in a week or so, or at least damage your hepatic and renal systems. Trouble is, it appears as a cold, rapidly degenerates into pneumonia, and then kills you due to fun things like hepatic failure. You have to smash it with antibiotics during its incubation period, after which time it is too late and you tend to die.

Protozoans are rare, the amebiasis and the Toxoplasmosis Gondii pathogens mainly reside in the sewer system. As for the elusive cryptosporidium... who knows. If it can get in your drinking water, you'll probably find it in stormwater too, and if ingested this protozoan will cause diarrhoea and stomach cramps. Giardia is also occasionally found in stormwater.

From the fungi and worm families, one finds the Ctenomyces interdigitalis (tinea) eumycete is uncommon, though the pathogens for ringworm and the favosan tinea dermatomycoses are present usually. Histoplasmosis is a fungi mainly obtained from pigeon shit dust which contains the spores... another reason why these pests are known as the rats of the air. It can become chronic and has permaturely ended lives of cavers, generally knocking the shit out of your lungs first, then ulcerating the respiratory tract, including nose and ears, eventually going for bone marrow.

Faecal Escherichia coli bacterium is common... indeed, most of the waterborne pathogens and parasitic organisms are available to you, including things from the pseudomonas family, the vibrios, the aerobacters, the proteus group, paracolobactrum, salmonella, various tubercelle bacilli... all of these are happy in water and use it as a transmission vector.

Generally it is the microscopic inhabitants which cause trouble. Drains carry significant amounts of sewer overflow, dog shit, rotting plant material and the occasional dead animal. Particularly after rain, drains contain elevated levels of sewer material, since the sewer is built to overflow into the storm drainage system instead of bursting out ino the street where the population can see it and get ill from it. If cut in a drain, attend to it as soon as possible with ethanol or other disinfectant. Deep puncture wounds (stepping on nails, broken glass, etc) are open routes to clostridium tetanii (tetanus).

Occasionally you will meet someone who lives in a drain or abandoned factory and they may consider you a trespasser. Since the economic rationalisation of the mental health system more and more disturbed individuals have been turned loose to fend for themselves. They tend to live in cheap housing such as the places we explore recreationally. When one is a guest, one respects the wishes of the host. If they suggest you should fuck off, don't wait for a stronger invitation. Sometimes, however, they are quite friendly and enjoy a visit.

I have yet to see a saltwater crocodile in a drain but I wouldnt be surprised if such were found in Darwin, where the tides are huge (8 to 10m) and the crocs are plentiful. I could only suggest that you carry a 12-gague shotgun with solid load shells, since crocs are fast, powerful and vicious. They are also patient, and if you go up a shaft will probably wait for you to come down again. These dinosaurs have not lasted for as long as they have by being stupid. Note that discharging a shotgun, pyrotechnic or explosive device in a confined space like a tunnel will significantly damage your hearing if you wear no earplugs, and the smoke from the burnt propellant is a respiratory irritant.

Mosquitoes tend to aggregate in stagnant puddles, they are worth your vigilance due to the pathogens they carry.

Large numbers of hibernating bats are sometimes found on the roof of drains. Some may carry Lyssavirus, which was responsible for a fatality in Queensland in 1996. They will not attack you, just leave them alone. They will do their utmost not to fly into you.

Ok, so you have just popped a cover in the middle of nowhere, and a drain yawns invitingly below you. Now then, is it safe to breathe? You can always lash out on pellistor-detector driven gas analysis systems, (Jaycar sell a kit (KG9178, $35) which picks up carbon monoxide and flammable volatiles, I don't know anything about their accuracy) but usually the average drain explorer will not have these things handy.

Manhole shafts tend to have spiders and cockroaches living in them. These organisms breathe oxygen like us, serving as a useful way to determine if O2 is actually present. Note that they can live on a lot less O2 than we can, and that just because there are a heap of cockies down there it doesn't mean the air is OK. Total lack of it will kill them as well as us, of course.

CockroachesThese guys are pretty tough, and some people are mis-informed as they think when they lift a manhole and see a hundred or so hanging about under the top of the manhole, that the air is OK. The reason they are doing this is because they are trying to get OXYGEN. Don't be conned and think cockroaches mean it is 100% safe.

One of the things the neophyte drainer discovers is that drains are slippery. That is, the surface is either covered in algal slime or is just implicitly smooth due to erosion and wetness. There is a wide variety of conditions, ranging from virgin rough concrete to slimy red brick, cement pipe, plastic, surfaces covered in pebbles, mud, broken glass and assorted members of the slime families. Until one is used to it, one tends to just fall over a lot, usually to the mirth of ones colleagues.

-http://www.infiltration.org/observations-approach.html