Category: Uncategorized

Nolisting

Nolisting is a spam fighting technique that works by listing an unavailable MX as the highest priority (lowest MX value) mail server. The idea is that any proper mailer will detect the unavailable MX and automatically retry the next highest priority MX record.

On Feb 7th, 2012, I dedicated one of my IPs to the job of not listening for SMTP traffic, set up a host record, and then configured a few mail domains with my faux MX as the highest priority.

On March 5, I removed the faux MX records. Over the course of a month, the half dozen users of these mail domains had all experienced the loss of valid mail and noticed. Undoubtably, they lost more valid messages than they noticed.

Before I removed the faux MX records, I did some sniffing of the SMTP traffic hitting my faux MX. During observation, most of the failures I witnessed were being sent by an application written using JavaMail. Apparently it’s popular with banks (for sending account notifications), news organizations, and online photo processors.

Systemizing Quotient

Dr. Simon Baron-Cohen’s Systemizing Quotient, Revised.

Scale: 0-150. Male average: 61. Female average: 52. Me: 101. I’m sure Jen also scores well above average on this assessment as well.

I recall taking a similar test years ago, and the results were comparable. Clichés like, “a place for everything, and everything in its place” were made for those of us that suffer from a high systemizing quotient.

Restless Genes

This explains a few things:

Researchers have repeatedly tied the [genetic] variant, known as DRD4-7R and carried by roughly 20% of all humans, to curiosity and restlessness. Dozens of human studies have found that 7R makes people more likely to take risks; explore new places, ideas, foods, relationships, drugs, or sexual opportunities; and generally embrace movement, change, and adventure. Studies in animals simulating 7R’s actions suggest it increases their taste for both movement and novelty. (Not coincidentally, it is also closely associated with ADHD.) — Restless Genes, National Geographic, Jan 2013, pg 44

I’ve always wondered why so many of the people I grew up don’t travel and are content to never leave the area in which they were born. The genetic difference is why it’s just not possible to explain to them why I did, why I climb mountains, why I’m restless, and why I thirst for adventure.

EditGrid

Apparently EditGrid let their domain name (editgrid.com) expire, and at present, anyone using their excellent shared spreadsheets is without access to them. What gets returned when someone currently visits www.EditGrid.com has been a 403, a parking page, and a 404 in the past 24 hours.

This morning, I did some sleuthing and found the working IP address of the www.editgrid.com web site. I have regained access to my spreadsheets by adding this little tidbit to my /etc/hosts file:

209.157.66.183 www.editgrid.com

 

Measures of Effective Teaching

http://www.metproject.org/

Of the 36 items included in the Gates Foundation study, the five that most correlated with student learning were very straightforward:

  1. Students in this class treat the teacher with respect.
  2. My classmates behave the way my teacher wants them to.
  3. Our class stays busy and doesn’t waste time.
  4. In this class, we learn a lot almost every day.
  5. In this class, we learn to correct our mistakes.

When Ferguson and Kane shared these five statements at conferences, teachers were surprised. They had typically thought it most important to care about kids, but what mattered more, according to the study, was whether teachers had control over the classroom and made it a challenging place to be. As most of us remember from our own school days, those two conditions did not always coexist: some teachers had high levels of control, but low levels of rigor.

From the Atlantic article, Why Kids Should Grade Teachers.

Which mobile phone carrier?

I have 4 lines with AT&T and am less than pleased. While data speeds are excellent, any call longer than 20 minutes will drop at least once. Coverage at my house is poor. AT&T’s voice quality is poor and has been for years.

My other major objection is their unlock policy. While AT&T will finally unlock iPhones after their contract is up, that still requires that I keep a 2-year old phone around for international travel. While exploring my options, I put together this TCO (total cost of ownership) comparison chart of the major US carriers (AT&T, Verizon, Sprint, T-Mobile) and a few resellers.

Mobile Phone Plans

The larger PDF also compares plans from Cricket, Virgin, and Ting. Pricing is shown for each plan with 1, 2, 3, or 4 phones.

Notes:

  • The One Time Net value assumes the value of an iPhone 5 in two years is $250. If you purchased an iPhone 4 two years ago, that’s about what your handset is worth today.
  • Ting with 3,000 minutes looks outlandish, compared to 1200-1,600 for everyone other plan. That’s because Ting and Virgin have no nights-and-weekends, or mobile-to-mobile. I looked at my past 12-months phone bills to determine how many minutes we’d need.
  • An excellent related post, Which iPhone 5 for a Global Traveller

Are charter schools good public policy?

From the paper How the worlds best performing schools come out on top by McKinsey:

Though the best charter schools demonstrated significant improvements in student outcomes were possible, and certain chains of charter schools showed that reliable models could consistently deliver improvements in a succession of schools, in the aggregate, the results of the charter schools did not significantly outperform those of other schools. The National Assessment of Educational Progress (NAEP) went so far as to suggest that students in charter schools slightly underperformed their counterparts in public schools, even after allowing for student background (Exhibit 4).

The most compelling argument against charter schools is that they don’t deliver better outcomes. Even after cherry picking the best (or as often, wealthiest) students out of the public school system.

They also measured the effect of simple fixes like throwing money at the problem (in the form of teachers) to reduce student teacher ratios.

Education spending versus student performance

Reduced student teacher ratios didn’t help. Other attempts at decentralizing educational policy ranged from ineffective to disastrous. So what does wok?

The highlights of the study are that, “To improve instruction, these high-performing school systems consistently do three things well:”

  • They get the right people to become teachers (the quality of an education system cannot exceed the quality of its teachers).
  • They develop those people into effective instructors (the only way to improve outcomes is to improve instruction).
  • They put in place systems and targeted support to ensure that every child is able to benefit from excellent instruction (the only way for the system to reach the highest performance is to raise the standard of every student).

This paper highlights findings I’ve read elsewhere–Finland and Singapore didn’t create the best educational systems in the world by segregating the students. They focused on improving the quality of instruction for every student. The difference between the best performing students in Finland and any OECD nation are comparable. The top systems are better because of how far up they bring their lowest performing students.