Marmoset
Michelle Lemay
The marmosets (/ˈmɑːrməˌzɛts, -ˌsɛts/),[3][4] also known as zaris or sagoin, are twenty-two New World monkey species of the genera Callithrix, Cebuella, Callibella, and Mico. All four genera are part of the biological family Callitrichidae. The term "marmoset" is also used in reference to Goeldi's marmoset, Callimico goeldii, which is closely related.
Most marmosets are about 20 cm (8 in) long. Relative to other monkeys, they show some apparently primitive features; they have claws rather than nails, and tactile hairs on their wrists. They lack wisdom teeth, and their brain layout seems to be relatively primitive. Their body temperature is unusually variable, changing by up to 4C (7F) in a day.[5] Marmosets are native to South America and have been found in Bolivia, Brazil, Colombia, Ecuador, Paraguay, and Peru.[6] They have also been occasionally spotted in Central America and southern Mexico.[7] They are sometimes kept as pets, though they have specific dietary and habitat needs that require consideration.[8]
According to recent research, marmosets exhibit germline chimerism, which is not known to occur in nature in any primates other than callitrichids.[9] 95% of marmoset fraternal twins trade blood through chorionic fusions, making them hematopoietic chimeras.[10][11]
Marmosets live in family groups of three to 15, consisting of one or two breeding females, an unrelated male, their offspring, and occasionally extended family members and unrelated individuals. Their mating systems are highly variable and can include monogamy, polygyny, and polyandry. In most species, fraternal twins are usually born, but triplets are not unknown. Like other callitrichines, marmosets are characterized by a high degree of cooperative care of the young and some food sharing and tolerated theft. Adult males, females other than the mother, and older offspring participate in carrying infants. Father marmosets are an exceptionally attentive example of fathers within the animal kingdom, going as far as assisting their mates in giving birth, cleaning up afterbirth, and even biting the umbilical cords attaching their newborn offspring to their mothers. Most groups scent mark and defend the edges of their ranges, but whether they are truly territorial is unclear, as group home ranges greatly overlap.
The favorite food of marmosets is carbohydrate-rich tree sap, which they reach by gnawing holes in trunks. Their territories are centered on the trees that they regularly exploit in this way. The smaller marmosets venture into the very top of forest canopies to hunt insects that are abundant there.[7]
Males and females look similar; Geoffroy's marmosets have a blackish-brown coat with elongated black ear tufts. They have a white forehead, cheeks and throat, with dark brown under parts and a black tail that is lightly ringed.
Marmosets also eat the gum of trees, produced by trees' defense system against damage to its bark. These monkeys are the only primates that regularly gouge their own holes to tap this gum (often gum is produced as a response to insect boring). Marmosets have relatively large incisors that they use as a chisel to collect the gum. The marmosets anchor their upper incisors in the bark and gouge upwards with the lower incisors. The amount of gum recovered is usually quite small and marmosets only spend about two minutes at any one hole.
Geoffroy's marmosets live in large social groups that can include as many as 20 individuals (more commonly groups of eight to 10) in which fathers, as well as other group members, provide extensive care for the young. Adult offspring may remain in the group and help care for their younger siblings.
The primary threat to Geoffroy's marmosets is habitat loss. There has been widespread destruction of the Atlantic forest, resulting in a patchy distribution, though population numbers are still abundant. Like many other small primates, they are occasionally collected for the pet trade.
Marmoset demo serverA demo marmoset server, currently available at -demo.cs.umd.edu:8080/.Anyone can sign up, and try to complete the provided exercises. More projects will be coming shortly,and we'll be allowing people to set up their own demo courses and define their own projects on our demo server. There is a web page and a piazza page for using the marmoset demo server and demo course. Marmoset Open source project, now on Google codewith a GIT repositoryThe Marmoset source code repository. Marmoset is opensource under the Apache 2.0 license. Survey on collection and grading of student programming projectsA survey about to assess current practices in the collection and grading of student programming projects. Results as of May 7thMarmosetPublications Links to Marmoset papers and bibtex entries.What is Marmoset?Marmoset is a system for handling student programming project submission, testing and code review. We've been developing it at the University of Maryland for over 5 years, Last fall, we handled 74,000 submissions for a total of 172 different projects from 1,700 students in 27 different courses. It works in all different programming languages, and is designed to work well with both very small and very large projects, such as our OS course in which a submission consists of tens of thousands of lines of code. Marmoset is described as part of a talk given by Professor William Pughon Innovation in teaching software development skills Dec 2nd, 2011 at SUNY Stony Brook. How most CS departments handle programming projectsThe faculty/instructor posts a project description, along with some sample input and the expected output, and are told that the project is due in 1-2 weeks (depending on the size of the project). Students start work on the project, ask questionsand get help in class and office hours. When they are ready, they submit the project, where it goes into some kind of electronicdrop box. No one looks at the submissions until after the project deadline, at which point a TA is given all the submissions and runs them against both the test data they were provided with and some additional secret test cases, which sometimes isn't made up until after the project deadline. Some submissions won't compile or run at all when the TA tests them, and the TA will have to determine if the submission wascompletely broken, or if it had some kind of platform or system dependence which keeps the code from working on the test machine. Perhaps one or two weeks after the project deadline, students get their grades back.How programming projects work with MarmosetThe faculty/instructor posts a project description, along with some sample input and the expected output (typically formulated asunit tests). Students work on the project, and whenever they want, they submit the project. Within minutes after submitting the project,they can go to a web page where they can see the results of testing their code against the tests they were provided and any tests they wrote. The results shouldn't be surprising, but the server testing will catch problems such as platform dependencies. For some languageswe also run tools such as static analysis and code coverage.If the submission passes all of the public test cases, the student is given an optionto perform a release test of the submission. Perhaps this is the poker game project, and the student performs a release test.They might be told:There are 12 release tests. This submission passed 7 release tests, and failed 5. The names of the first two failed tests are "full_house" and "4_of_a_kind"(the names of only the first two failed release tests are revealed).Now, a student can think "oh, I think I know what I did wrong," change their code and resubmit. But performing a release testrequires using a release token. Students are given some number of tokens (typically 2 or 3) and they regenerate 24 hours after being used.This has many repercussions.
- Students have an incentive to start early: the earlier they start, the more opportunities they have toperform release tests.
- Students are told that when they learn that they failed a release test, they shouldn't try to first fix their code.Instead, that should try to write a test case that replicates that failure, so that when they next performa release test they have some confidence that they will actually pass the release test.
- If students make an incorrect assumption that causes them to fail many of the instructor's test cases, they find outbefore the project deadline and have a chance to ask questions and try to fix their code.
- When it gets down to the last day and the last two release tokens, it replicates much of the pressure that real softwaredevelopers feel to ensure the qualify of their code, and helps them develop good software development skills.
- in-progress reviews, done by an instructor or TA before the project deadline. This can either be initiated by a student request for help (via a submission help-desk system handledby Marmoset) or by a TA.
- An instructional code review after the project deadline. In this case, student submissionsare assigned to instructional staff.
- Peer reviews, where each student might be assigned to review the submissions of two other students.
- A J2EE webserver (we've used Tomcat in our deployments), using servlets, jsp,GWT, and javascript. We can use either LDAP or open-id for authentication.
- An SQL database (we've used MySQL in out deployments).
- One or more buildservers. For various reasons, we never run student code on the machine thathosts the submit server and the database. Instead, build servers connect to the submit server,and present credentials for the courses they are authorized to build projects for.If there are any appropriate submissions, the build server downloads them, disconnectsfrom the submit server, builds and tests the submission and then uploads the results to the submit server.We can run multiple build servers for a course to provide both redundancy and quick turn aroundtime for project testing.