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Dan Lentz
Works at Dean & Company
Lives in Greenwich, CT
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Software Engineer: Clojure + Scala, Elmar Reizen
Amsterdam, NL

Elmar Reizen is one of the largest online travel agents of the Netherlands selling package holidays via our website www.vakantiediscounter.nl. We build all our systems in house with our own development team of full stack developers. We do that by leveraging new technologies like:

- Apache Spark for distributed data processing
- Play & Akka for a scalable back-end
- Ruby on Rails plus React with ClojureScript for our Response website

Elmar Reizen is an informal company where we use Agile development and best practices to deliver with little overhead, fast time to market, and high quality. We do this all from our beautifully situated office at the canals in the center of Amsterdam.

What you will be doing

You will join our Product Team where you will be:

- Sharing your expert knowledge on the above technologies
- Gaining knowledge on the above technologies from your expert colleagues
- Writing lots of (clean) code that goes to production continuously
- Spent 10 percent on private projects to find the next big thing

Your Skills

- 5+ years as a professional software developer
- Solid experience with one of the technologies we use
- A strong interest in functional programming
- A passion for learning and sharing knowledge
- Experience with Big Data, Spark, Hadoop is a plus
- Experience with Solr or Elastic Search is a plus
- Experience with React, Scalaz, Play framework is a plus

What we offer

- A good salary
- 30 paid holidays days
- Opportunities to attend conferences, trainings, workshops, etc.
- Discount on your holiday trips (of course :)
- Vibrant company culture
- Support with relocation (visa, housing)
- Support with 30% ruling
- Get information on how to apply for this position.
Elmar Reizen is hiring a Software Developer | Scala, Clojure | Spark, Solr, Agile for a full-time vacancy located in Amsterdam.
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My programming music this week has been heavy on Shatter Me by dubstep violinist +Lindsey Stirling
Really cool stuff.
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Wish me luck...
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:P
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#nanoreef vibrant and healthy this Saturday. 🐠
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*Envy*
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Here's another one, +Mark Derricutt +Jimmy Arogén +Nick Alcock -- have you seen Mr. Robot ? I'm reserving judgement (the plot seems to get a little hazy during some of his opioid binges) but this show is not the typical USA network pulp-scifi. I've actually been reasonably comfortable with the show's depiction of a programmer and "hacker culture". 
Created by Sam Esmail. With Rami Malek, Carly Chaikin, Portia Doubleday, Martin Wallström. Follows ...
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/me wonders if Ghost in the Shell counts. Probably not: present-day hackers can't hack your senses, thank goodness :)
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So, the two anemones in my #nanoreef swapped places last night.  The behavior and motivations of anemones remain a mystery to me.
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Oh, man do I want one, and blue blubbers :-D 
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ClojureScript REPL for iOS now available in the App Store.

Replete by FikesFarm, LLC
https://appsto.re/us/NieA8.i
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Blue Blubber #Jellyfish Catostylus Mosaicus

#nanoreef
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May/Jun 2015 Edition of Coral Magazine has lots of good info on Jellyfish, if anyone is looking.

#jellyfish #nanoreef
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So, blue blubber jellyfish are very beautiful and (relatively) tough as far as jellyfish go. The only issue I have run into so far is feeding. Blubbers can't eat fish food, obviously. They also can't eat "jellyfish food" which is fine for moon jellies and those that eat larger particles, but way too big to be caught by a the fine oral net of a blubber. So what do they eat? Zooplankton. The first attached picture shows a blubber as it is feeding on zooplankton, and I was not seeing this from my blubbers.

My first course of action was to seed a natural population of (mostly) tropical Copepoda in the kreisel's refugium: pseudopsyclops, tisbe, tigriopus, and rotifers. These act like a microscopic cleanup crew among the live rock, and will become established in the tank. To feed Copepoda and help this process along, I have been adding 2ml per day of concentrated phytoplankton, which also will live in the water column There are always a few copepods that wind up getting sucked into the main tank, so the idea is that these jellies will have natural feeding opportunities throughout the day.

But this will likely not be sufficient for the jellies main diet, as they will require a bit more food than the tank can likely produce sustainably on its own -- and exotic live zooplankton are not available cheaply or easily enough to simply keep the jelly's area filled with floating dinner.

So, the solution is to hatch fresh artemia, which is available in (dry) egg form, very very inexpensive, and hatches overnight. So, problem solved, right? Well, almost...

My first attempt to hatch artemia was a bit of a dud. I put the eggs in some water with table salt (I don't know why. I had perfect seawater available. I was just following the directions...). The yield from this approach was negligible. There were a few artemia among the millions of unhatched eggs, but the product was unusable.

Next, I tried adding an airstone to a small bucket of eggs and salt water, which did produce a few more live artemia over the course of the next day or so, but very few of the eggs actually wound up staying in suspension. 95% sat on the bottom and didn't hatch.

The next thing I tried was an actual hatchery, you can see in the photo below. The shape of the soda bottle is perfect to allow bubbles of air to rise from the narrow base and keep nearly all of the eggs in suspension. I was hatching zooplankton by the millions!

However this was not exactly the end of my problem. See, the issue is that while freshly hatched artemia is extremely nutritious, the husks of the egg shells they hatch from are not. In fact, it's not good for them at all. So, I naturally tried every bone-headed approach to this problem that occurred to me, including a few frustrating hours trying to suck out individual artemia one at a time with a pipette. I also considered some approaches I read about online: apparently, the correct combination of acids will melt the husks, leaving only the outer membrane. Most will still hatch. Oh geez...

So, finally I stumbled onto this other idea online. It is actually marketed as a children's school-age experiment to hatch brine shrimp. It has a simple, unaerated black box, and a clear collection cup separated from the dark box by a lid with a small aperture the creatures can swim through, as they are attracted to light. So, alone this device winds up with a very very low density of product -- a fraction of a percent of the total eggs I put in. But the result is pure! Only live brine shrimp will swim upward through the aperture to get to the light. Husks remain below.

So, what I discovered is that by combining these two techniques I now have an unbelievable production pipeline of fresh artemia, perfectly sorted from their husks. The soda bottle bubbler produces live artemia/egg husks by the millions. To produce a final product, I simply squirt a turkey baster full of this artemia soup into the black box, wait an hour, and the collection cup is absolutely brimming.

At this point I'm producing about 10x the artemia I would need to just jellies, so my nano-reef and pipefish get the leftovers. Adding zooplankton to my reef has also had noticibly beneficial results. The corals just seem absolutely vibrant. And the fish are having a ball, since they now have little snacks to chase around all day. And it's an extremely clean form of nutrition since it basically stays alive in the water column, rather than settling and decaying.

I've got jellies with full bellies!


#nanoreef #jellyfish
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We get them on northern beaches, I have only run into them twice after a storm and they were washed up.
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Got a couple of nice #nanoreef shots this morning. The interesting red dragonette near that purple-tip Sebae anemone is Synchiropus Moyeri -- a relative of the mandarin fairly new to the trade which is reef-safe, nano-friendly, and amenable to conspecifics.
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Currently
Greenwich, CT
Previously
New Castle, DE - Newark, DE - Pennsville, NJ - Dallas, PA
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Alpha Nerd in Beta Test
Work
Occupation
Consultant / Software Developer
Skills
Clojure, Common-Lisp, Graph Database, Datomic, Software Development
Employment
  • Dean & Company
    Senior Software Engineer, 2015 - present
  • Consumer Reports Magazine
    Software Engineer, Graph Database, 2014 - 2014
  • Bridgewater Associates
    Software Engineer, Research Technology, 2014 - 2014
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Male
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