Statistical Methods and Analysis of Environmental Health Data

The following was written by SukhDev Mishra,Ph.D., Division of Bio-Statistics, National Institute of Occupational Health, Indian Council of Medical Research, Ahmedabad(India)

group shot

Statistical Methods and Analysis of Environmental Health Data Workshop group.

I was fortunate to attend the SAMSI workshop on Statistical Methods and Analysis of Environmental Health Data last week in Mumbai. It focused on various topics related to the statistical analysis of environmental health data, some of which discussed latest methodological development in this field, particularly during the first day’s opening lecture from Professor Joel Schwartz.

Time series data has proven to be critical in the assessment of systematic impact of environmental factors on human health. Professor Francesca Dominici, a researcher with significant contributions in this area was a very dynamic and enthusiastic co-leader for this workshop. She discussed in length the statistical principles and assumptions of multi-site time series analysis along with careful interpretation of such data. Due to technological advances and regular measurement availability, time series data could be accessed and easily analyzed with the techniques elaborated by Professor Dominici, which will be integral to the success of my future studies.

Working Group 5 - Gene x Environment Interactions

Working Group 5 – Gene x Environment Interactions

The Gene x Environment Analysis & Epigenetics lecture taken by Professor Bhramar Mukherjee provided very useful information on interaction/additive and multiplicative models citing practical applications in area of environmental health that she developed. Her very creative way of teaching, blended with great sense of humor, kept us engaged so much so that we wouldn’t blink for a second.

Spatial statistics is a critical part for environmental health data, so it was helpful to have the basics covered by Dr. Safraj Shahul Hameed and Dr. Brian Reich well. Professor Donna Spiegelman presented a wonderful talk on measurement error starting from statistical notations to complete logit function (being a statistician ….I always love this part J ). She put great effort explaining Regression calibration method for MS/EVS and algorithms. Interesting talk!

Working groups were engaged in different exercises that included working on different problems/real data sets generated through various participants and coming up with new analysis and interpretation of data. I worked on Exposure Modelling of Ambient and Household Air Pollution for Acute and Chronic Health Effects. I enjoyed working with my fellow WG colleagues- Kalpana Balakrishnan, Santu Ghosh, Donna Spiegelman, Kevin Lane, Joel Schwartz, Sourangsu Chowdhury , and Poonam Rathi. Fine scientific arguments during the process of analysis were the crux of our exercise; thanks to Joel, Kalpana, Donna and Kevin especially.

This is no way a comprehensive description of this workshop, just my thoughts. I would also like to record here that I learned from each and every speaker and fellow participant. It was a gathering of great scientific minds and very inquisitive researchers. My understanding is that one of SAMSI’s objectives is to foster a culture of collaborative research among Indo-US researcher in area of public health; and I could see that coming true as we collectively discussed ideas on how to continue our work in mutual scientific engagement. I hope these efforts result in great scientific endeavors in coming time for environmental health priorities.

People drinking tea during a break

Enjoying afternoon tea.

One of the unique features of this workshop was meticulous planning by the team of organizers, be it scientific contents or overall execution by Professor Richard Smith, Professor Sujit Ghosh, Professor Francesca Dominici, and Ms. Krista Coleman whose scientific management and interaction with participants was very encouraging.

My working experience mainly includes working in pharmaceutical industry earlier, as biostatistician, and I consider myself a beginner in environmental health. This workshop has helped me to gain more scientific perspectives in this area by leaps and bounds.

This kind of knowledge sharing exercises may prove very helpful for researchers in the area of statistics and epidemiology to address India’s most pressing public health needs. Thank you SAMSI, Harvard, ISI-Kolkata and all of the other participating organizations for such a wonderful experience!

 

 

Advertisements

Op-Ed in Post-Gazette: Why Forensic Analysis of Crime Scenes is not as Reliable as you Think

SAMSI was featured in an op-ed piece in the Post-Gazette that was written by Lucas Mentch, Maria Cuellar, William C. Thompson and Clifford Spiegelman, all whom are participating in the SAMSI program on forensics this year.

The piece focuses on the Netflix mini-series, “Making a Murderer,” that raised questions about the actions and motives of law enforcement. Read their piece here.

Postdoc Profile – Benjamin Risk

Ben on top of a mountain in the Galapagos

Benjamin Risk traveling in the Galapagos Islands.

As Ben Risk was growing up in Northbrook, Illinois, (a suburb of Chicago) he always liked to look out in the yard and see the birds soaring above. “As a kid, I was really interested in biology and ecology and birds,” said Ben.

He went to Dartmouth for his undergraduate work where he decided to major in environmental and evolutionary biology. He collected data on the breeding demography of a songbird called the black-throated blue warbler, which got him interested in statistics. “As an undergraduate I had to do a lot of statistical analysis and I had to get help on that because I didn’t have the training. That was the first exposure I had to the importance of statistics,” Ben commented.

Ben writing notes in a notebook on a mountain

Ben in Wrangell St. Elias National Park in Alaska.

After graduating, he moved to Oakland, California, and worked for a few years for an economic consulting firm, Charles River Associates, where he applied statistical methods to anti-trust litigation and environmental economics. “We would come up with a dollar value for how much companies had increased prices through collusion and things like that,” Ben explained, “I was following the instructions of the statisticians, and that also motivated me to consider becoming one of those statisticians.”

He then went to graduate school and received a Master’s degree in environmental science from the University of California, Berkeley. His thesis developed a Bayesian formulation of a metapopulation model. “I was realizing that by specializing in statistics I could be involved in many different fields. I also wanted to be involved in research that would have applications to human health, so I decided I wanted to pursue biostatistics research,” said Ben. It was at that point that Ben enrolled in the Ph.D. program in statistics at Cornell University.

A lot of people at Cornell have been involved with SAMSI, and Ben’s advisors, David Ruppert and David Matteson, also mentioned SAMSI as a place to apply to after he finished his degree. The program on computational challenges in cognitive neuroscience was also announced at JSM 2014, which prompted him to email Haipeng Shen.

Ben is currently researching statistical methods for the analysis of MRI. He is working on one project with Hongtu Zhu, where they are developing a spatial model of the heritability of cortical attributes that are correlated with intelligence. “We are looking at cortical thickness and volume to assess the degree of nature versus nurture,” he explained. He is also working with Daniel Rowe to examine how image processing may affect the conclusions people make regarding which parts of the brain are connected.

Ben typing in his computer on a rock in the Galapagos

Taking measurements of a tortoise in the Galapagos Islands.

Ben is involved in three working groups. He is in the Functional Imaging Methods and Functional Connectivity working group with Jon Aston and Hernando Ombao. He is in the Big Data Integration in Neuroimaging working group with Martin Lindquist and Timothy Johnson. He is also in the Acquisition, Reconstruction, and Processing of MRI Data working group with Dan Rowe.

Ben is an NIH trainee, so will continue his research at SAMSI next year. He is also associated with UNC’s biostatistics department, so will spend time there as well.

When Ben has time, he likes to go cycling and to play guitar. Of course, he still loves birds, so he also likes to go birding when he has time.

Taking a Different Road – Being a Statistics Major

The following is written by Sarah Lotspeich, University of Florida who attended the SAMSI Undergraduate Workshop focusing on Computational Neuroscience.

I declared my Statistics major in the eleventh grade, approximately halfway through my AP Statistics course. As everyone around me pondered medical school and the many types of engineering, I knew that my choice seemed unconventional. Now three years into my undergraduate degree, I have met only a handful of fellow Statistics majors to date. During the third week of October, however, this changed forever as I attended the SAMSI Undergraduate Workshop.

Duke Chapel

Duke Chapel.

It was a gorgeous fall day (a pleasant surprise for me, as my typical “fall” in Gainesville, Florida includes a few fallen leaves and a high temperature in the 80s) in Research Triangle Park, North Carolina. Budding statistics and mathematics students from across the country gathered to explore computational neuroscience, and to enjoy fantastic food. Always eager for an adventure, I flew in as early as possible the day before the workshop to get maximum exploring time in Durham. Perhaps a bit TOO eager, I walked over eight miles through Downtown Durham and to both edges of Duke University’s gorgeous gothic campus.

Dame's Chicken and Waffles

Excellent chicken and waffles place!

Fret not, however, as I was well fueled by Dame’s Chicken and Waffles and fondue from the Little Dipper. Needless to say the local area surpassed my every expectation and left me excited to wear scarves and learn more about statistics the following day. The mingling began at approximately 7:30am the next morning, as over thirty of my fellow “numbers people” bonded over bagels and oatmeal. I was so excited to hear from people who care as much about significance tests and p-values as I do!

The presentations commenced with an absolute bang as Dr. Ciprian Crainiceanu of Johns Hopkins University immersed us in “Neurohacking”. He outlined the basic principles of converting MRI images from picture to a system of numbers, and by the end of the hour left us with a data set and the necessary code to explore it independently. One of my favorite components of the workshop, actually, was the interactive nature of each presentation with the integration of R or Matlab code.

Guest lecturers introduced many fascinating facets of computational neuroscience, and I especially enjoyed how my knowledge on the subject compounded with each additional lecture. As the workshop progressed I found that I was relating information from one speaker’s presentation back to material I learned even hours previously, and even today I walked away with a nice basis on the topic. It very much feels as if I went from zero to one hundred with this material, and I appreciate the challenges posed to us by the complicated subject matter.

Beyond the presentations, the field trip to the laboratory for psychiatric neuroengineering at Duke University provided a “behind-the-scenes” glimpse at the processes of data collection that create the massive sets we dealt with during lecture. I was also just happy for any excuse to ogle the beautiful campus once more. Each new speaker and opportunity brought about new questions to ask and facts to learn, so I was happy for the constantly changing environment of the workshop from lecture to lecture, or even breaks for the field trip or panel.

students by SAMSI sign

From left to right: Jordan Zeldin, Eion Blanchard, Sarah Lotspeich, Michelle Zamperlini.

The many bus rides provided unexpectedly pleasant opportunities to meet new people, as well, as I was shuffled into new groups with each trip. I thoroughly enjoyed swapping stories about my university – about the weather, everyday dress code, the statistics department – with people from other schools! And I was even lucky enough to give suggestions about things to do and places to eat in Florida, as one of my new friends is planning a trip to the Sunshine State soon. Perhaps the most unexpected bonus to this experience was the people.

This was honestly one of the most incredible groups of students, and upon learning more about each person and their involvement I am absolutely honored to have been selected among them for the 2015 SAMSI Undergraduate Workshop. Though the workshop lasted only two day, the people I met and research I was immersed in will carry through my entire career. I cannot emphasize enough the importance of this experience and how strongly I recommend it.

There is a 100% probability that I would love to return to SAMSI sometime in the future.

Learning about the challenges of computational neuroscience

The following was written by Thomas Witelski, Associate Director at SAMSI and Professor at Duke University in the Mathematics Department.

At some level, everyone is aware of the pressing medical and societal
challenges of neuroscience from media coverage of the growing impact of
neurological diseases like Alzheimer’s and Parkinson’s. Understanding the
brain at a scientific level has been identified as one of the central
challenges for this century’s research, as reflected in the magnitude of
resources invested in the NIH’s BRAIN initiative and the European Union’s
Human Brain Project.

attendees sitting in the auditorium

The opening workshop for CCNS was held at the NC Biotech Center.

In August, a diverse community of researchers converged at the NC
Biotechnology Center for SAMSI’s opening workshop for the Challenges in
Computational Neuroscience (CCNS) program. The presentations by leading
researchers on clinical, cognitive, computational and theoretical aspects of
brain research yielded many very lively discussions. Some talks addressed
technical issues, but many pointed to big fundamental questions on
exploring what might be nature’s most intricate black box.

Martin Lindquist speaking at the podium

Martin Lindquist, Johns Hopkins, speaking at the opening workshop.

A long history of anatomical studies has established the general features
comprising the human brain, but great challenges lie ahead in making clear
how the structure and functions of the brain relate to each other. Many of
the talks in the CCNS workshop addressed methods in neuroimaging. Martin
Lindquist (Johns Hopkins Univ) gave a lecture over viewing the various
modalities for functional imaging of brains in vivo, including functional
magnetic resonance imaging (fMRI), positron emission tomography (PET), and
electro/magneto-encephalography (EEG/MEG). These techniques differ in the
technologies used to collect data, but more importantly, they fundamentally
differ in the physiological types of behavior they monitor — in terms of
either blood flow, metabolic activity or electrical activity in the brain.
The methods have different limitations and trades-off in terms of spatial
and temporal resolutions, and represent the current state-of-the art in
clinical methods of collecting neuroimaging data.

Several talks in the meeting addressed fundamental statistical and
mathematical questions on image processing and how to use collected data
(possibly coming from multiple scans) to obtain the most accurate possible
maps of the brain’s structure. Of particular interest is the use of
neuroimaging data to infer the networks of connections among parts of the
brain, called the field of connectomics. In this direction, Max Descoteaux
(Univ of Sherbrooke) showed how diffusion in MRI images could be used to
identify structural connections within the white matter of the brain.

Another major branch of neuroscience research explored in the workshop is
based on “bottom-up” modeling of time series of neural activity in networks
of connected neurons. Physiologically-based models of chemical/electrical
activity like the Hodgkin-Huxley equations can effectively reproduce the
dynamics observed in individual neurons. Equivalent reduced models, like
the “leaky-integrate-and-fire” neuron, can then be used to give statistical
descriptions for the patterns of spikes typically recorded in EEG data.
Workshop presentations in this area included talks by Robert Kass (Carnegie
Mellon), Kenneth Miller (Columbia) and Uri Eden (Boston Univ).

Returning to studies at the “whole-brain” level, many speakers touched on
the computational challenges involved in analyzing the huge datasets that
have been collected in connection with some clinical studies. The importance
of using mathematical and statistical methods to interpret clinical
neuroscience was also highlighted in talks on neurodevelopment by Raquel Gur
(Univ Pennsylvania), behavioral studies by Ruben Gur (Univ Pennsylvania)
and the influence of anesthesia on brain activity by Emery Brown (Harvard).

two people looking at the poster

Looking at a poster during the CCNS Opening Workshop.

Many of the advanced topics addressed in the workshop were also introduced
in a Neuroscience Summer School that was held in connection with the CCNS
program in July. The research focuses begun in the workshop are being
carried forward in several working groups, two graduate courses and further
workshops

Five things I learned at the Forensics Tutorial

fingerprint analysis lab

Participants got to try their hand at doing a fingerprint analysis.

I don’t know about you, but I am fascinated by forensics. Crime scenes are puzzles waiting for someone to solve. So, I, along with some other staff members, sat in on part of the Forensics tutorial held in August.

Here are five things I learned while I listened in on the tutorial:

1)Unlike “CSI” or whatever your favorite cop show might be (mine is “Dexter”), the methods used at the crime scene are not nearly as scientific as you would expect. That’s where statisticians and applied mathematicians come in. There is a plethora of areas where adding statistical or mathematical methodologies to the field of forensics can make a tremendous impact in helping law enforcement catch the right people.

2)A lot of forensic evidence comes from inductive inferential processes, which is not a very good/reproducible way to gather evidence. Bill Tobin, from Forensic Engineering International, told us that they do not share error rates and there is no “peer review” for the evidence.See one of his presentations here.

3)There are many factors that are often overlooked or are not explored in firearm toolmark evidence (Firearm toolmarks are used to associate or eliminate a particular firearm as a murder weapon comparing characteristics imported to bullets and cartridge cases when it cycles through a gun.) but there are ways that forensic experts could use a more scientific approach to make this a more credible piece of evidence. See Cliff Spiegelman’s talk for more information about this.

Andy Parker dusting for fingerprints

Andy Parker shows the group how he dusts for footprints.

4)Andy Parker from the Wake County Crime Bureau Investigation team is awesome! He talked about what his job entailed and showed us several slides (sorry, they cannot be shared) of dead bodies and had us guess if it was a murder, suicide or death by accident. Then he explained how one could conclude which was correct. Later, he had us all gather around and showed us how they dust for prints, including footprints. It was really neat!

Herbert David Sheets

Herbert David Sheets, Canisius College and University at Buffalo, talks about bitemarks.

5)The uniqueness of bite marks is not been scientifically established, and the uniqueness of a bite mark to make a unique pattern in someone’s skin has also not been scientifically established. See Herbert David Sheets’ presentation for more info.

Overall, this is a fascinating topic that applied mathematicians and statisticians have traditionally not been involved with, but that needs your attention. Saving an innocent person from being in prison and/or catching a criminal who may still be free is vital to keeping our society whole. You can still get involved by attending one of SAMSI’s subsequent workshops which will be posted on the SAMSI website sometime in the near future.

Postdoc Profile – Christopher Strickland

Christopher Strickland on a hill with the ocean in the background

Christopher Strickland hiking in New Zealand.

SAMSI postdoctoral fellow, Christopher Strickland was born in Houston, Texas and lived briefly there and in Dallas before he could really remember either place. He grew up in Oxford, Mississippi. His grandfather was Chair of Modern Languages at the University of Mississippi and helped to establish a study abroad program, and his grandmother was originally from France, so many summers his father and grandfather traveled to France. When Christopher went to ” Ole Miss,” in the honors college, he minored in physics before switching degrees and getting a double degree in Mathematics and French.

At first he was following a more pure math route. He went to the University of Florida in Gainesville for his Master’s degree and was studying logic, but after about a year and a half, he realized this was not the area he preferred. After changing his focus to dynamical systems and defending his Master’s thesis, he stayed in Gainesville for a year as he tried to figure out what to do next and taught mathematics at Santa Fe Community College. He knew he would prefer to get into an area that involved applied math instead of pure math. He became interested in mathematical ecology and had heard that Colorado State University had a great program in ecology and the natural sciences, so he applied there to get his mathematics Ph.D.

Christopher considers Patrick Shipman, who was a new faculty member at Colorado State at the time, and Gerhard Dangelmayr, who is the Chair of the department, to be his mentors. They were also his co-advisors. Christopher and Patrick started collaborating on projects right away.

“I was headed toward dynamical systems which is really related to mathematical ecology, so I worked with Patrick and Gerhard for the next six years,” Christopher said, “I still collaborate with both of them, and we are currently applying for a research grant to work with the U.S. Fish and Wildlife Commission.” Christopher has also collaborated with Patrick Shipman and Snehal Shetye at Colorado State on a project modeling the mechanical properties of spinal cords.

Nate Burch told me about SAMSI originally,” said Christopher. “Nate and I were colleagues at Colorado State.” So, when the Ecology program was announced, he applied and was accepted.

Christopher Strickland standing on a rocky edge

Christopher Strickland hiking in Australia.

While he’s been at SAMSI, Christopher has worked on getting various parts of his dissertation re-written into smaller parts so that he can publish each part in various journals. He has three of the four published. The manuscript of the fourth one is completed, and has been submitted as of June 2015.

Christopher has been participating in two working groups this year: The Tipping Point group and the Physical Ecology group. The Physical Ecology group led by Laura Miller, has been particularly interesting for him. “We recently had this really great workshop at SAMSI, which was for the people participating in the working group. We invited Nadia Kristensen from the University of Queensland who brought in all this great data from parasitoid wasp release and spread. That’s been really nice because I mostly do modeling of dynamic systems and the model that she had with this data could be something I could help her improve,” he commented.

“We are also working on a review paper, which is something the working group conceived of sometime around December. The entire working group and even some other people, including some ecologists and my advisor from Colorado State, Patrick, is working on this review,” Christopher said. He believes the review will be completed by the end of this summer.

Much of Christopher’s research focuses on networks, specifically looking at spread and control of contagions on the network. One example would be to look at container shipping networks or airline networks. He is working on a grant that is looking at white nose bat syndrome that involves a network of caves. While bats could spread the disease themselves from cave to cave, there is also the concern that hikers or cavers could get the fungus on their boots and spread the disease when they hike in a different cave. By figuring out how these networks work, it may help ecologists figure out where the disease might spread next, or help them to get a disease under control.

Christopher Strickland makes a kick

Christopher practicing Cuong Nhu.

When Christopher is not at work, he is either playing a game of soccer (he used to be on a math league!) or he is practicing the art of Cuong Nhu, (meaning hard/soft in Vietnamese) a type of martial arts that was brought to the United States in Gainesville, Florida. Christopher is on target to get his black belt, probably in about a year. “A lot of scholarly people actually do this type of martial arts. It has been a good way to network,” quipped Christopher. He also spends time with his girlfriend, Anne Ho, who is a theoretical mathematician. They like to travel a lot, many times to national parks or overseas.

In the fall, Christopher will be teaching at the University of North Carolina at Chapel Hill while he completes his second year as a postdoctoral fellow for SAMSI.

Exploring the dispersal patterns of insects at the SAMSI Ecology Transition workshop

Erin Schliep

Erin Schliep attended the SAMSI Ecology Transition workshop and wrote this blog post.

The following was written by Erin M. Schliep, PhD, Postdoctoral Fellow, Department of Statistical Science at Duke University

During the first week of May, the Ecology Transition Workshop was held at SAMSI, once again bringing together statisticians, mathematicians, and ecologists from around the country. This workshop marked the conclusion of the the Statistical/Mathematical Ecology Program that began in August, 2014.

At the beginning of the program, interdisciplinary working groups were established, each focusing on a different research area within mathematical and statistical ecology. The working groups held both in-person and virtual group research meetings throughout the year. At the Transition Workshop, members of the different working groups presented on current research projects that stemmed from the year-long program as well as exciting directions for on-going collaborations. Some of the main themes from the workshop included networks, infectious disease, dispersal patterns of insects, joint species modeling, and data fusion of multiple data sources.

woman checking her cell phone

Checking messages during a break.

As a statistician focusing on ecological and environmental applications, I thoroughly enjoyed the meeting that combined technical statistical methodology and detailed information on the ecological processes of interest. The diverse scientific backgrounds of participants in the program led to interesting discussions, including the behavior of ant colonies, the distance at which scientists aboard ships can accurately identify birds, and the polygamous mating patterns of the North American barn swallow.

Speaking on behalf of the multivariate models working group focusing predominantly on statistical methodology, the workshop was a great opportunity for us to present our current research and to learn of new and exciting ecological datasets to apply our new methods. Our current aim is developing computationally feasible joint models for species distributions that allow for multiple types of data, such as continuous, count, or composition data. Even though the program is completed, our group continues to meet and has established research goals for the coming months.  I know that many of the other working groups within the Statistical/Mathematical Ecology Program also have on-going research and I am excited to learn of their future progress.

 

Recovering from the Epigenetics Workshop

three people talking at the meeting

Michael Zhang (UT Dallas), Zhaohui (Steve) Qin and Shili Lin (Ohio State, co-organizer)

The following is from Zhaohui (Steve) Qin, Associate Professor, Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, who attended the SAMSI Epigenetics Workshop March 9-11, 2015.

I was sitting near my departure gate at RDU Wednesday afternoon, waiting for my return flight after attending the SAMSI workshop on Epigenetics. Suddenly I feel so tired. I have good reason for being exhausted. I feel that my brain has been set on high-spin mode all of the last three days. This is so strange. It is supposed to be a low-intensity meeting. Only a handful of talks and just about 50 attendees. It feels so different from attending other conferences such as ENAR, JSM or ASHG.

First, I know almost everyone at the workshop. For the speakers, I either know them personally, or I know their work. At every break, I barely have time to grab a cup of coffee, not mentioning checking emails. There is always someone I want to talk to within five feet of me wherever I go. And not like the massive conferences, there is plenty of space at the corridor in this cozy SAMSI building. So I feel totally comfortable to join in a conversation.

Inkyung Jung (UCSD), Chenchen Zou (Jackson Lab) and Miriam Huntley (Harvard).

Inkyung Jung (UCSD), Chenchen Zou (Jackson Lab) and Miriam Huntley (Harvard).

Second, there is so much to learn, to talk about and to think. Epigenetics is a hot area these days, new technologies and new findings are emerging almost daily. This is a great opportunity to immerse myself in this exciting field, with so many experts in these areas walking around me. Thanks to Dr. Shili Lin, the set of speakers at the workshop is amazing. A few senior and very experienced scientists plus a large cohort of young and energetic young scientists. In the past three days, I learned several new ideas or results/findings. And I am pretty sure my fellow attendees felt the same way. Everyone is asking each other what’s new. I won’t be surprised if new collaborations were started right at the workshop. I wish more conferences I am going to will be like this one. And I am certain that I will come back to this nice little building when the next opportunity arrives.

Group of people sitting looking at laptops during a break

Yongseok Park (U Pittsburgh), Inkyung Jung (UCSD)

I felt so sympathetic towards my colleagues Karen Conneely and Hao Wu, who have to drive six hours back home. How can someone still have the energy to do that after three long days is really beyond me. I am determined that I am going to sleep soundly during my flight back, no matter how bad the turbulence is.

And I did.

My Impressions of the SAMSI Multivariate Modeling in Ecology Workshop

By Andrew Johnson, postbacc at North Carolina State University

group listening to a talk

SAMSI held the Multivariate Models in Ecology Workshop March 2-4.

Folks came in from across the country earlier this week to contribute to SAMSI’s Multivariate Modeling in Ecology workshop. Living in Raleigh, I shared in the excitement but enjoyed a much shorter commute than most. During my drive to SAMSI on the morning of the first day, I must say that I had a few reservations. I was new to the working group and unsure about my ability to contribute to the group’s progress. I was immediately relieved to find that my fears were misplaced. The atmosphere throughout the workshop was warm and industrious, welcoming of all questions and suggestions. Two of my favorite features were the flexibility of the schedule and the fluidity of the subgroups, both being obvious products of our group’s openness to input. There was a predetermined schedule for each day that was quickly adjusted by the group’s suggestions. This was also the case for group sizes. When appropriate, the group would quickly split into smaller, project-based subgroups. These self-guided adaptations made it possible for everyone involved to get the most out of their experience.

Three women discussing a poster

Poster session at the workshop.

The workshop was designed to address a few of the issues that the Multivariate Modeling working group has grappled with in the past. The group has been interested in understanding how the spatial positions of multiple species can be interrelated and co-vary with environmental influences, as well as the best way to model those relationships. Needless to say this poses a few inherent challenges. One of the primary questions that the subgroups focused on was that of dimension reduction for datasets describing the interactions among multiple species and environmental variables. Complementing the efforts on dimensional reduction, the subgroups also worked on developing improved methods for interpreting their computational results. In addition to the questions above, our group discussed strategies for assembling separate datasets into one coherent “picture.” This required consideration of each dataset’s reliability and corresponded to the computational weight placed on each. Fortunately, my favorite question of “where to eat” was answered with ease each day, as the workshop was fully catered with excellent food!

Andrew Johnson

Andrew Johnson at the poster session and reception.

I gained a great deal from this workshop, and had a blast doing it! I am thrilled to have been a part of it.