Photodiode amplifier noise

Some areas here have had success with a strategy of painting over it within 24 hours. If it's done aggressively and consistently, they mostly stop doing it (and go elsewhere?).

Clifford Heath.

Other option: Hang a web cam and when you see a guy doing it remotely open a nozzle above that releases a skunk spray. Should also make it really easy to identify the suspect, for days, and I am pretty sure they won't be back within the next 20 years ;-)

My Hispanic son-in-law speaks no Spanish, my oldest son is fluent in (Mexican) Spanish and Portuguese ;-)

...Jim Thompson

Does he also have an accent?

Same with a neighbor of ours. But it really becomes sad with Laotians where the kids speak English with an accent yet cannot communicate with their parents who only understand Laotian :-(

I sure wish I was. It would make life a lot easier out here. I wanted to take Spanish in high school but was told that Latin was mandatory and with all my elected math and physics courses there weren't enough hours left to sign up for one more language. That really ticked me off, having to learn a dead language. A class which I promptly flunked. Talking about motivation ...

Accents can become really messy when you move around a lot. Most people cannot figure out where I came from unless they are from there.

In the little dorf where I lived in Germany, two local teens thought it would be neat to tag a bridge. Absolutely unheard of, IME. Someone called the Polizei, but not to report them, to save them.

The villagers, you see, didn't appreciate their town being defaced. A crowd gathered 'round the teens and proceeded to beat the living daylight out of 'em. The Polizei hauled the kids off, saving their teen-age tails.

Said teens, black and blue, were later seen on the same bridge, scrubbing it clean.

They don't stand with that there.

James Arthur

Wow. :-)

Realistically you probably can't let the crowd get off without charging them with assault too (well, OK, MAYBE JUST ONCE you might :-) ), as police departments can't allow vigilantism on a recurring basis either.

Of course these days the kids' parents would sue anyone they could identify for millions in damages for touching their precious little darlings.

Anyone have a link to Sheriff Joe's rebuttal of the ASU study that purportedly found the recidivism rate to be no different with prisoners in his system vs. those in "traditional" prisons? (Wikipedia just says Joe said the study was flawed.) I'm not leading into suggesting that Sheriff Joe ought to change his ways here, I'm just curious to read the rebuttal since I'm incredulous that "Joe's way" *wouldn't* result in lesser crime. But perhaps I just don't understand the hooligan mindset well enough...

---Joel

Rodger, I'll pass that along, & hope it's fun.

Cheers, James

Well, I figure there are maybe three Types...

1. The real "honest" criminals (well, probably quite dishonest..): murders, rapists...Enron execs...
2. The "situational" criminals, put there by culture (or rather, the subculture they belong to), of which these hooligans are a subset, and
3. The non-criminal criminals, including drug offenders and music pirates (victims of unjust laws -- depending on your meaning of "just"...)

And intersecting these classes, there are also a few Mindsets:

1. The "I didn't mean to" type. Something like an everyday shmoe, caught in a bad situation, of which s/he has acknowledged his/her fault and learned his/her lesson. These are the people who might be considered "prison successes", in the sense of prison as a reform institution.
2. The "natural born killer" sort. These include hard core serial killers, the kind of people who (by nature or nurture) have a magnet sitting next to their moral compass. This especially goes by degree, ranging from normal to homicidal. Presumably, most inmates have some of this characteristic, since they willingly did something which went against the law as we know it. One could argue that the "non-criminal criminals" (NCC) class follows the same pattern, but in that case I draw the distinction that 1. most people don't think the NCCs are all that bad (they aren't arrested for violent crimes, for example), and
3. there is a tremendous quantity of NCCs.
4. Those who recognize that there are laws against their behavior, and may even be morally opposed to it themselves, but who nonetheless commit criminal acts out of survival. These include petty theft and gang activity (and related enterprises, like drug supply). If the conditions leading to these subcultures didn't exist (mainly, low socioeconomic status), the people born into those conditions also would be different. These people will tend to be repeat offenders, because, even though they may recognize the law of the land, that law is not the law of their environment, and it's not how they were raised.

I recognize there may be considerable overlap in these six categories. I haven't made a special analytical effort to seperate them into an optimal, linearly independent set of attributes.

Now, as far as prison as a reform institution:

Those of Type #1 and Mindset #2 in particular represent the hardened criminals, the kind which either don't want to change (prison is a setback, regardless of any opportunities -- reform -- it may offer), or cannot change (I suppose that, just like you "can't fix stupid", you "can't fix Jeffrey Dahmer", for example). These prisoners represent a baseline which cannot be reformed and will continue to commit crimes, regardless of attempts to pacify them.

Mindset #1 prisoners (spanning all three Types) will almost always return to society peacefully. They know what happened, and they know better. Only if prison changed them for the worse (maybe they accidentially dropped the soap?) might they start a criminal career. With a fairly high reform rate regardless of prison style, this type represents a baseline in reformability.

Those of Mindset #3 are the big variable which the prisons can (maybe) control. If the prisons do nothing, these types will probably return to the same city, same family and same friends which got them into this problem in the first place. If the prisons were extremely effective at reform (friendly atmosphere, heavy social, education and work programs, etc.), most of these people would return with a new look on life, seek out new friends and start anew.

So as far as prison success goes, I think there are a few levels to the inmates. Many don't belong; some will (most likely) continue to commit crimes; some will (most likely) never again commit a crime; and many will either return, time and again, or start a new life, escaping the evil cycle. It is the duty of the prisons (and/or legislators) to minimize the first population, and reform the fourth as best they can.

Tim

P.S. I originally wanted this post fairly short, to complement your brief comment. But since it's late, it seems to have turned into a long expression of personal speculation. I really should find something more useful to write about when I get all "writey" like this.

Any leftist analysis of Joe's Tent City is bound to be "flawed".

There have been repeated investigations of Tent City by the Feds. NO indictments.

...Jim Thompson

the capacitance matching is almost a fluke, a quick rule of thumb, and it happens to be because IIRC : the FET gain (gm) is function among other things of the device geometry , the FET input capacitance is also function of the device size, while the output noise is function of the detector and fet input capacitances.

Then , the S/N just "happens" to be maximised close to the capacitance matching point. Actually , the optimal detector to FET input capacitance ratio may be 1:0.6 , or something not equal , but close to 1:1.

Jure Z.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Joe wasn't the first to use tents either, which I would think he probably knew when he made his own tent city and thus correctly figured he was on solid footing.

It is a little odd that he closed down one level his of jail just to "populate" tent city though. Seems like a bit of showmanship there?

I do have to admit I like his flashing "Vacancy" sign. :-)

The wikipedia article has a long list of the lawsuits again the MCSO, and notes that to date the county has paid out ~$50M in settlements (although it doesn't break down how much of that came from the county's insurance vs. directly out of their budget). Do you think you're getting your money's worth? ;-) They tend to imply that this is somehow directly Joe's fault, and while having a sheriff like Joe probably makes it more challenging to find officers who aren't just "good old boys" (a lot of morons figure that "tough on crime" equates to "no holds barred" when it comes to the treatment of prisoners), I don't see compelling evidence that having someone other than Joe around would have clearly been any better.

As they say... If you can't do the time, don't do the crime!

---Joel

How interesting. Here in Providence, RI all you have to do is pickup the phone and call the Graffiti Control hotline. A week or so later a crew comes out and scrubs, paints and gets rid of the graffiti.

Our town has that policy, and it helps, but it sure hasn't stopped it

We had one idiot that kept at it for years, always signing the same handle. One local motel owner had put up video cameras, and caught this guy tagging his sign (He had to climb a wall, walk along it (12 foot drop!) and shimmy along the roof to reach it. Motel owner is also the head of the public safety commision...

One less tagger!

Charlie

Huh? I know of no such closing. The main jail is full of the hard-ball types, so misdemeanors and DUI's are in he tents.

Yes ;-)

None of those (IIRC) are from the tents, they come from druggies and "restraint chairs", suffocations, etc, in the main jail.

Of course the ACLU sues and the county pays rather than fighting the lawsuits... bunch a fairies ;-)

The leftist weenie newspapers (the kind that think Napolitano has a half-a-brain... that's all we have now) are constantly on Joe's case. But they're failing as subscriptions drop... good riddance ;-)

Likewise... Bye! Bye!, Boston Globe ;-)

(BTW, Beware, another storm just passed over, heading East. Didn't even sprinkle here... "decimation" when it reaches NY ;-)

...Jim Thompson

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Wikipedia sources it from this article:

Anti-Joe sites such as arpaio.com have this to say: "Sheriff Joe Arpaio: He built the tent city jail because of overcrowding in the regular jails.

Truth: To insure there were enough inmates for the much publicized tent city jail he closed an entire floor of the First Avenue Jail."

I of course don't know at all one way or the other.

But clearly a lot of people support Joe, and I'd definitely think twice before committing a crime if I lived in his county!

---Joel

Ever know of an honest leftist weenie ?:-)

...Jim Thompson

Joerg writes

Me too, (substitute German for Spanish). But returning to photodiodes...

I've studied this circuit and I'm quite confused by it. Apart from the issue of resistances being higher than they need to be, surely this topology is not using the JFETs to their best advantage. According to Phil Hobbs' excellent article hither -

the point of adding a cascode front end is to isolate the photodiode from the summing junction. (I think J2A/J1A form a cascode current source.) But these Korean researchers are connecting it to the opamp-created virtual earth (ie where the feedback resistor goes back to). I suppose they isolate the photodiode's capacitance from the actual inverting input of the op amp and thus stop it oscillating, and the input bias current of their chosen amp (OPA27) is tens of pA so the differential JFET front end maybe compensates for thermal drift etc, but they don't seem to be taking full advantage of the possibility of buffering the photodiode from the op amp. They'll lose bandwidth...?!

It's kind of like they've taken the photodiode input to the wrong node. They've added a bunch of components to the front end... and then overlooked the advantages of bootstrapping.

Hmm.

Concerning criminal mentalities, the most interesting studies I've come across have been by economists and psychologists morethan sociologists. They ask questions like "why" and discover that young folk have different perceptions of risk / reward to older people; that people who are denied opportunities by society - say, because they have a criminal record already - don't feel like stakeholders, etc. One study found that gang members in New York's most violent areas figured they weren't going to live to age 20 anyhow, so it made little difference how they lived their lives.

They do lose BW but it seems they were only interested in single-digit Hertz regions. What surprised me was the total absence of any input protection. Exceed a few volts from an ever so slight charge ... poof ... JFET gone.

It looks like they didn't have the help of a hardcore hardware engineer. And they haven't read Phil's book :-)

My opinion is that people who have done their time they should be taken off the "stigma list", except maybe for sensitive jobs such as law enforcement. Similar to the driving record in many states where an xyz violation is removed from the database after x years but it remains on the "hidden side" so a judge could still see it. Otherwise they'll remain pariahs almost for the rest of their lives and that can turn folks willing to become good citizens into desperados. And it does.

Absolutely. People change. I'm not the same person I was 10 years ago; and major life experiences such as becoming a parent (and presumably, going to jail) can be personality-altering.