Arizona’s Petrified Forest National Park is known for its stunning views and beautifully preserved petrified wood. The trees here are Late Triassic in age (230-200 million years ago) and are preserved in agate, an often multicolored form of granular quartz. These fossil trees are what bring people from all over the world to the park each year but the petrified wood is not the only thing of significance to a paleontologist. The park is also an important source of vertebrate fossils from the Triassic.
The bones that are preserved here are weathering out of what’s left of local exposures of the Chinle formation. Most of the fossil-bearing rock here has long ago weathered away leaving the petrified trees scattered around the area. The bones tend to be less resilient than the wood so paleontologists rely primarily on the remaining outcrops of Triassic mudstone to find vertebrate fossils still in place in the mudstone.
As part of a month-long expedition across the Midwest, Virginia Tech’s paleobiology group visited PEFO (Petrified Forest) over the last week in order to collect fossils and/or help out as needed with work in the preparation labs on site. The weather has not been cooperating however (it is monsoon season after all) and this has limited our time in the field. We were only able to spend a few days out on the bone beds but we didn’t come out empty handed!
A day of prospecting in the canyons around our target site yielded lots of phytosaur (large extinct croc-like reptiles) bone fragments too damaged to keep and some teeth and osteoderms (bony armor plates) worth retrieving. Because of the weather during the days leading up to our arrival, we were cut off from the target locality but by the next day, the road out to the site had dried up enough for us to drive all the way in and actually start excavating there. The site, called “the green layer,” is a thin layer of greenish-grey mudstone that contains abundant vertebrate fossils including those of phytosaurs, aetosaurs (large armor plated reptiles), and dinosaurs.
We recovered several bone fragments and osteoderms that had to be jacketed as well as several hundred pounds of sediment from the layer. The extra sediment we collected can be screen washed for microfossils back at Tech. Altogether, it was a productive few days of collecting (despite the weather) and an incredible experience working in the park! Some of the specimens we collected could potentially help with reconstructing the fauna and ecosystems of the Triassic of what is now the American Midwest!
We managed to catch a lizard (Holbrookia maculata). The local wildlife is beautiful and quick!
Some of the crew looking at calcified root casts in the mudstone. These formed as a result of calcium carbonate precipitating inside the voids left by plant roots that, at one point in the distant past, infiltrated the sediment.
Over the past week, the VT Paleobiology group, led by Drs. Michelle Stocker and Sterling Nesbitt, headed out to Wyoming to find fossil bones from the Triassic (~199 to 252 million years ago) as a part of a month-long expedition to do field work across the Midwest. The area around Lander Wyoming is home to several exposures of Triassic sedimentary rocks, exactly the kind of place you want to look to find vertebrate fossils from that time. We spent the week prospecting several localities and weren’t disappointed!
The main focus of the trip has been to uncover a large (~8 foot long) fossil phytosaur that was found in 2015 on a previous expedition. These creatures looked superficially like crocodiles but are distantly related. They had armor plating all over their bodies and long snouts filled to the brim with sharp, serrated teeth. The fossil in question lies on a ridge of exposed sedimentary rock that happens to be incredibly difficult to reach. The hike is roughly a mile from start to finish and the elevation change is over 1000 feet. We had to haul tools, personal supplies, and eventually fossils up and down this path twice a day for 6 days!
The first day on site was mostly spent scoping out the area around the phytosaur fossil which had been capped (coated in plaster and burlap to protect it) and buried at the end of the 2015 expedition. The goal for this day was to prospect for new fossils and new sites in the Chugwater formation, the formation that contains the phytosaur skeleton. We found lots of phytosaur teeth and some small fragments of miscellaneous bone from the first site that was located in 2015 but nothing new.
On the way back from the quarry, we found the bones of a horse that had died shortly before the 2015 expedition. The 2015 team dubbed it DH (dead horse) and left it to skeletonize in the desert. Two years in the elements has certainly done the trick! We collected the skull and lower jaw, the sacrum (fused pelvic vertebrae), half of the pelvis, and some of the limb bones for use as a reference in the paleobiology lab at Tech.
The first hike was a challenge but by the next day we were getting the hang of it. We arrived on site a little earlier and were able to do some more thorough prospecting in a larger area around the phytosaur fossil. A few of us found several large fossil amphibian bones in a productive layer of purplish rock near the phytosaur! These amphibians, called metoposaurids, were enormous, reaching lengths up to 6 feet. In addition to prospecting, we were able to uncover the phytosaur and begin working on excavating it further.
We spent the whole rest of the week excavating the phytosaur but it just keeps getting bigger! There’s no sign of it ending so we couldn’t get it out this trip but hey, plans change. After capping what we uncovered, the whole fossil was then buried just like last time. It’s too big to move at this point and still well encased in rock. We’ll have to come back next year!
We finished off our stay in Wyoming with some prospecting at different sites down the road from the phytosaur locality. We ended up finding a crazy new locality that’s just overflowing with fossil bones! This could be another place to quarry in the future.
By Gifty Anane-Taabeah, a Ph.D. student in fish and wildlife conservation, College of Natural Resources and Environment, and an Interfaces of Global Change Fellow with the Global Change Center at Virginia Tech
[About the blogger: My Ph.D. research focuses on quantifying the genetic variability within and differentiation between natural populations of Nile tilapia Oreochromis niloticus in different river basins in Ghana. We have very little information on the genetic diversity of O. niloticus outside the Volta system. Furthermore, O. niloticus populations in major river basins in Ghana including the Pra, Ankobra, and Tano currently face diverse threats including habitat destruction from illegal small-scale gold mining activities, overfishing, and pollution. Using a population genetics approach, my research seeks to generate baseline data that will aid in conserving the species’ genetic diversity and local adaptation.]
Today is Wednesday June 7, 2017. I am currently lodging in Half-Assini, a border town between Ghana and our western neighboring country, Ivory Coast. I spent most of my day at Elubo, another border town about 45 minutes-drive from Half-Assini, in search of O. niloticus samples. Wednesdays are market days in Elubo and an opportune time to scout for wild-caught O. niloticus. This is especially important because Ghana shares the Tano River with Ivory Coast and the data generated will be useful for conserving the species in both countries.
I have successfully collected samples from the Pra and Ankobra Rivers, and I am amazed about the morphological differences I have observed among individuals within each river. I am already excited about what I will discover after my genetic analysis. I am hopeful that my research will provide the much needed baseline information about O. niloticus genetic diversity in Ghana, and add to the body of knowledge on the population genetics of O. niloticus in West Africa.
My research also seeks to identify wild populations of O. niloticus with a natural local adaptation to future climate conditions in Ghana. The average water temperatures in rivers vary along the latitudinal gradient of Ghana. Our previous experimental studies using different populations from the Volta River basin have revealed that some northern populations of O. niloticus may already be adapted to high temperature conditions, similar to the future climate conditions expected for southern Ghana.
Given this background, I have spent the last four months setting up and running three separate experiments to quantify the adaptation of different wild populations to varying temperature conditions both under laboratory and outdoor conditions, as well as to quantify the heritability of the growth rate trait from parents to their young.
I have a great local team comprising local fishers, government scientists and graduate students who have helped me with the collection of adult fish, monitoring of their growth and reproduction, and selection of their young for the experiments. I am hopeful that the data obtained from this research will be useful in selecting suitable populations and developing them for aquaculture in Ghana and sub-Saharan Africa.
I am chugging café con leche and downing a whole plate of fresh papaya and pineapple while I wait for Dani to pick me up at the hotel. It was a late night, with a delayed flight from Atlanta to Panama City, but I am anxious to get out to the field with Dani and Angie today. Dani arrives and we weave our way through crazy traffic heading east out of the city. Every bus stop has a fruit stand and I implore Dani to stop for guanabana, my favorite tropical fruit, but he says it is too dangerous to pull over at the bus stops, and after watching a few buses pull in and out, I have to admit he is probably right.* We eventually leave the highway at a small town and stop to buy a few giant avocados en route to the field station. A few river and stream crossings later, and we arrive in a tropical paradise.
Dani and I are waiting in the open air “comedor” for Angie to return from scouting out a field site. When she gets there, she immediately starts cooking. We have a great lunch of tortillas and chorizo, with some of our recently acquired avocado. After lunch, Dani and Angie start packing for the hike to the field site. They are doing an important conservation project here—seeing if endangered toads that have been raised in captivity can survive at a site where they used to live. The hardest part of the project, hauling all the enclosures to the site (one per toad) and putting in the toads, was done a few days ago. Today we are going to go check on the toads and swab them, so we can monitor potential infection by chytrid fungus, the skin pathogen that likely drove this species to the brink of extinction in the first place. That swab will also allow us to assess the other microbes on their skin, so we can see how their symbiotic skin microbes change following re-introduction. We think these microbes might play a role in disease resistance, and so we want to track how they might change over time in the field in these toads that are so susceptible to chytrid fungus.
We are hiking up a very steep trail, just outside of the station. I stop to look at a frog (or maybe just to catch my breath). There is so much life in the lowland tropics– so many things to see. Hiking in a tropical forest, as a lover of biodiversity, is like no other experience. Every step brings something new to see… a frog leaping from underfoot, a giant caterpillar, a gorgeous orchid on a branch overhead, an amazing mushroom growing out of a stump, a flock of birds that make a ridiculous amount of noise but can’t be seen, the slightly eery sound of howler monkeys in the distance. We stop to watch two pied puff birds that look like small black and white kingfishers. They are sitting on a branch right next to the trail, near a termite mound and they seem as curious about us as we are about them. We keep moving and are headed downhill now, to a stream. We walk down this stream, on slippery boulders and large cobbles. Dani points out a small frog carrying tadpoles on her back, looking for a place to put them in the stream. It seems a precarious venture for such a small creature in a big stream, and I wish her well. We climb down the edge of a small waterfall that looks like it should be on a postcard, and soon we arrive at a larger stream, where the enclosures are, and the toads. It took an hour to get here and we have a lot to do, so we find the first enclosure downstream and get to work. Dani and Angie carefully check and swab each toad. Most are hiding in the leaf litter inside the enclosures, which is damp to the touch. I watch my students, trying to help a little where I can, and listen to the sounds of the forest—I am reminded of how much I love being in the field, and how that used to be a much bigger part of my job.
“Does everyone have extra batteries for their headlamps?” Angie asks. Dusk is rapidly approaching and we still have about 10 frogs left to swab. We are walking upstream to the next set of enclosures, which are spaced out along the banks as the stream topography allows. I pause momentarily, and Angie says, “Keep walking, please”, with a bit of urgency. I move forward as my brain ticks off the things that might have produced that tone in her voice. Fer-de-lance, bullet ants, jaguar…That is as far as I get on my list before Angie points out the coral snake climbing through some short palms to our right at about shoulder height. It is beautiful with its bands of red, yellow and black, and they aren’t aggressive snakes, so I stop to enjoy it for a moment.** When we arrive at the next enclosure it is nearly dark, and the loud squawking of blue-headed parrots is filling the dusky jungle. Soon it is completely dark, and we are working by headlamp to the plinking calls of hopeful male glassfrogs. The toads are sleeping on top of the palm fronds in their enclosures now that it is dark, so they are easier to find as we finish up our work.
It took us 90 minutes to get back to the field station from the end of the enclosure transect. We walked very carefully, eyes staring for vipers in the leaf litter on the trail as if it was a magic eyes illusion that would spring to life at any instant. At one point, Angie stopped to point out a large tree with a sparse line of bullet ants climbing it, and a few seconds later we all skirted around a bullet ant crossing the trail. We have nothing but respect for the insects given a “4+” for the pain of their sting on a 4-point scale. After shockingly cold showers, we had peanut butter, bananas and crackers for dinner, and maybe a little rum. I climb into my hammock for the night, feeling grateful that I have the opportunity to be here for a few days with these two amazing graduate students in this incredible forest.
*A few days later, Dani found me a guanabana at a city market, and I ate the whole thing, essentially all by myself. It was so good.
**We saw the snake again on the way out, and Dani determined it was a false coral snake, actually a colubrid, but still beautiful.
By Casey Lowe, a Virginia Tech senior majoring in Humanities, Science, and the Environment in the College of Liberal Arts and Human Sciences
Between 1845 and 1849, the Irish Potato Famine destroyed crops and ultimately killed more than 2 million people in Ireland. The culprit? A highly destructive oomycete pathogen called Phytophthora infestans. Oomycete pathogens are a class of eukaryotic microbes that are similar to fungi and are well known for their destructive history.
Relatives of the oomycete pathogen that destroyed Ireland’s main food source in the 19th century are being studied at Virginia Tech today. Unlocking their genetic secrets could provide powerful benefits to agriculture worldwide. Plant disease causes a 15-20% yearly reduction in global crop productivity, and in today’s growing world food stability is volatile. By 2050 the world’s population is projected to have risen by 30% indicating the rising importance of food production efficiency and stability. That’s where plant pathologists come in.
Kasia Dinkeloo of Delaware, a fourth-year Ph.D. student in the department of plant pathology, physiology, and weed science in the College of Agriculture and Life Sciences, is working with John McDowell and Guillaume Pilot, both professors in the department, as well as four fellow graduate students, to analyze the manner in which oomycete plant pathogens invade plant hosts and extract nutrients.
Kasia found her interest in plants as a high school student. Her original plan was to attend art school, but after reading many books on plants for an art project she found a new passion to become a scientist, a route she also believed would be much more beneficial for her life. While completing her undergrad at the University of Delaware, Kasia took a class on plant pathology and immediately knew it was the direction she wanted to take.
She and her team, directed by McDowell and Pilot, operate in two different labs in Latham Hall investigating the mechanisms by which oomycetes alter the host plants metabolism to fit their nutrient requirements. Some oomycetes are challenging to study because they are biotrophic, meaning the organism must remain in the living host to complete its life cycle, and therefore cannot be cultured or grown away from the plant in order to be studied.
Much like humans, plants have complex and efficient immune systems consisting of a network of thousands of proteins working together. However, plant pathogens can still successfully invade and extract resources from the host plant by overcoming the plants immune responses. The mechanism by which oomycetes suppress plant immune responses is well studied and increasingly understood, but little research or knowledge exists that explains how pathogens trick the plant into giving away its nutrients. For Kasia, this unknown is the most exciting part of her graduate research, but also the most challenging.
For the past three years, Kasia has been developing a method which will eventually allow the team to isolate the specific cells that contain the oomycetes feeding structures from the bulk plant tissue. Once Kasia’s molecular technology is complete, the team will have access to RNA data that should contain genetic evidence of how oomycetes are capable of their takeovers. This information will bring the team much closer to their end goal: to create genetically modified versions of these plants that will resist nutrient extraction by the pathogen.
The test subject is a plant known as Arabidopsis thaliana, a commonly used model organism for pathology studies. The oomycete Hyaloperonospora arabidopsidis is a natural pathogen to Arabidopsis thaliana, making it a perfect candidate for the studies. By understanding how oomycetes successfully hijack nutrients from Arabidopsis, Kasia will be able to isolate the enabling traits and then create modified plants that suppress or are unaffected by the pathogen interference. This will help create plants that won’t give up their nutrient sources, cutting the supply line to the pathogen.
Kasia is well aware of the economic value of her research beyond its scientific implementations. “The value of our science is a dollar value,” said Kasia. “If we can create healthier plants with a higher yield, it will decrease food prices, something the consumer will see in the grocery store and directly benefit from.”
Using pesticides for the chemical control of pathogens has been successful in some ways, but they have caused irreversible environmental damage as well as generated new pathogens resistant to pesticides. By creating modified plants with a genetic defense against oomycetes, the need for pesticides could be eliminated altogether.
According to Kasia, genetically modified plants will be essential for feeding our growing population. She believes creating more food on less land will only be accomplished by working on the plants themselves, not just the environments in which they are grown and produced.
“I’m going to feed the world, that’s the dream! Food is security,” she said.
Q&A: Meet Kasia
Hometown: Wilmington, Delaware
Major/Year: Fourth-year Ph.D. student
Fralin Advisors: John McDowell and Guillaume Pilot
Other Degrees: Bachelor of Science from the University of Delaware
Why do you want to be a scientist?
I really enjoy plant science because it’s a really beautiful way to see the world. I like knowing that the work I do is not only very fulfilling to me as a person, but can be used to help feed our population.
What created your interest in plant pathology?
I knew that plant science/plant pathology was for me after a freshman year course at U.D. called “People and plants: feast or famine.” I loved learning about how plant pathogens and plant growth shaped so much of history, and how understanding plant disease is a key part of food security for the future. After that class, I guess I was hooked.
Career goals after graduate school?
As far as ultimate career goals after the Ph.D., it’s hard to give a clear answer since I am so undecided. But whether I am in academia or industry, I would really love to keep exploring different aspects of plant-pathogen interactions and stay as close to a research lab setting as possible.
Favorite hobby outside of school?
I have a dog; he’s the best ever. I really like having a dog because it reminds me to go home and not spend all day in the lab. I love hiking and outdoor activities as well as powerlifting.
Favorite thing about Blacksburg?
People here are so nice! I thought I was nice when I moved here, but I was just nice for Delaware. There is such a good sense of community here.
I’m currently writing this at 2:30 am, Madagascar time, as I wait for the local taxi brousse (or bush taxi) to take me from the small town of Daraina to the coastal cities of Vohemar and Sambava where I can finalize my research permits. Let’s just say that things here don’t always go according to a western schedule, as my ride is already half an hour late and there’s no sign of car, driver, or even other passengers! Fortunately, music from the town’s only discothèque is loud enough to keep even the drowsiest of travelers wide awake.
For the past two months, I’ve been in and out of Daraina and its surrounding forest fragments conducting surveys to estimate population sizes of several lemur species. The focus of my study is on the critically endangered golden crowned sifaka, which is found only within about a 40 mile radius of town. But, as lemurs are earth’s most threatened group of mammals and are endemic to (or found only on) the island of Madagascar, we’re keeping records of the six other lemur species also found in the area.
Golden-crowned sifakas are definitely among the most charismatic of the lemurs, with their long legs and tail that help them to leap 20-30 feet between tree trunks, bright white bodies accented by a crown of golden hair (thus the name!), and mellow disposition expressed by bright, orange eyes. Unlike other lemurs in the region, they’re protected from hunters by local taboos. However, as people from other regions come here to try their luck at finding gold, and law enforcement is still recovering from a recent coup d’état, this protection may be short-lived. Perhaps an even greater threat is the continued loss of habitat due to slash-and-burn agriculture, logging, and ever-expanding cattle pasture that are a direct result of Madagascar’s rapidly growing human population.
Thanks to conservation efforts by the Malagasy NGO, Fanamby, I have some hope for the region’s incredible biodiversity. But long-term protection can only be guaranteed if local people embrace the importance of conserving their few remaining natural resources. As one of the poorest countries in the world, Madagascar’s rich biodiversity has significant potential to bring in much needed international tourist and research dollars. Hopefully the continued presence of researchers, such as myself, not only will improve our understanding of how species are responding to ongoing global change, but also will impress upon the locals the international significance of their natural heritage.
Well, finally! It’s 4 am and we’re about to see just how many people, mattresses, sacs of rice, and live chickens can be squeezed into what should be a 12 passenger van (right now I count at least 20, 1, 10, 9, plus luggage). It’s going to be a long, bumpy ride!
Guest blogger Brandon Semel
Ph.D. student, Department of Fish and Wildlife Conservation, Virginia Tech
The wind whipped tiny mist droplets across our faces as we zipped up our jackets against the chilly air. It was unusually quiet, a surprisingly stark contrast to the constant drum of life in the lowlands.
The vegetation consisted of pale shades of tan and grey green, colors seemingly faded by the thick glaucous coating and fine hair like structures covering the stems and leaves of the succulent plants.
Rudy, our guide, explained how the fuzzy wool like fibers on the puya plant, a high altitude bromeliad, is used by hummingbirds to build nests to protect growing nestlings against the frigid year round temperatures.
Carpets of fine long grass waved back and forth like a horses mane against the fog shrouded peak of Pichincha. The city of Quito spanned the valley below, nestled between the volcanic Andean mountains.
It was a breathtaking experience to conclude our visit to Quito!
What initially motivated me to go on this trip was my fascination with herpetology. Reptiles and amphibians are often misunderstood and underappreciated creatures, and the opportunity to visit the Ecuadorian rain forest where biodiversity of these creatures is abundant has been incredible to say the least.
It rained all night and sporadically during the day, so that special day at Shiripuno was an especially lucky one for finding frogs and snakes. On our day hike we saw two crested forest toads that camouflage so well they’re easily mistaken for fallen leaves, and a red backed dendrobatid (poison dart frog). When Erin Dailey and I were setting up our research project we saw an Amazon horned frog, also known as a pacman frog, that can grow so large it will feed on mice! It had beautiful markings on its back to help it camouflage with the leaf litter around it, so it can sit and wait for prey instead of searching it out. The yellow lines curving throughout its face looked electric and mesmerizing.
At dinner I showed Dr. Moore the pictures of the pacman frog, and he just about jumped out of his seat from excitement and jealousy. We went out for a night hike to look for it and other critters lurking in the night. We didn’t find the pacman frog again, but found other amazing amphibians and reptiles. First we saw a caecilians (the third and often forgotten group of amphibians after frogs and salamanders) feasting on a large earthworm in the middle of the trail. It was one of the strangest and most interesting things I’ve seen on this trip. It resembled a snake but was more tubular and very slimy. Those who tried to grasp it couldn’t hold it in their hands for longer than a few seconds. As we continued, we found 3 giant monkey tree frogs, bright green frogs with serrated-like sides and pale gray eyes with a prominent black slit. We were extremely lucky and got to watch it wax itself with its legs for a moment. As we approached a stream filled with fallen leaves, we began to search for Pipa pipa (an aquatic frog) and Mata mata (an aquatic turtle). Dr. Hopkins amazingly enough was able to find a Pipa pipa within all the leaf litter underwater. I could hardly even see it before he pulled it out from its hiding place. It still baffles me that he even spotted it in the first place. Under the leaf litter it resembled a brown crab, but once it was brought to the surface it looked prehistoric. It had a flattened head as if it had been stepped on and very long slender front toes. Last time Dr. Hopkins visited the lowland rainforest finding a Pipa pipa was his goal and now I can see why.
Walking back from the stream we saw two snail eating snakes, one of which was a banded calico snake with a beautiful pattern of white and black bands that faded into a browner banded pattern. This was one of my favorite night hikes yet due to the diversity of herps we saw. It’s amazing how these animals have these perfect adaptations to blend in in their special niche within the rainforest. With these incredible features that allow them to camouflage so well, it makes me wonder what other creatures are looking back on us as we venture through their home.
~ Virginia Tech student Caroline Tribble
Follow the Adventure! You are invited to follow the VT Ecuador students as they report back from South America during their 3-week journey, May 16-June 7. They will be blogging @VTResearch and posting to Facebook, Twitter, and Instagram using the hashtag #VTEcuador. – See more at: http://blogs.lt.vt.edu/ResearchBlog/#sthash.g5Fc56wz.dpuf
Arrived at Yanayacu last night after a long 14 hr travel day. Rough weather conditions with many inches of rain made the long canoe ride out of the jungle and later bus transfers quite the adventure. As we ascended from the lowlands into the mountains we passed more than a dozen mud slides that had been cleared the same day. We are lucky that we made it in at a good hour…Could have been a very long night waiting for roads to be cleared. Still dumping rain now.
A bit hypnotizing on the tin roof of the biological station. Enjoying a coffee in the cold cloud forest at first light, watching a trogon (pictured left) about 5 meters away (or it’s watching me). Hummingbirds are starting their morning feeding frenzy. Life is good and the students are starting to rise. It is going to be another great day.
~ Dr. Bill Hopkins, trip co-leader and professor of fish and wildlife conservation at Virginia Tech
Throughout this trip, Matthew Lacey and I have been setting out camera traps, hoping to catch glimpses of the wild cats of the Amazon. We’ve been placing them on game trails and near locations where the local guides have seen tracks. At Sani Lodge, we were lucky enough to get a picture of an ocelot on the first night they were set. Unfortunately we haven’t gotten any more cat pictures, but we have collected pictures of lots of other jungle wildlife. Through these cameras, we’ve seen red brocket deer picking their way through the undergrowth, agouti shuffling past, and a Grey-Winged Trumpeter investigating the novelty in this strange object on its territory. We’re looking forward to setting the cameras out again now that we’re in the cloud forest, and getting candid snapshots of wildlife.
~ Virginia Tech student Elizabeth Zadnick
Follow the Adventure! You are invited to follow the VT Ecuador students as they report back from South America during their 3-week journey, May 16-June 7. They will be blogging @VTResearch and posting to Facebook, Twitter, and Instagram using the hashtag #VTEcuador. – See more at: http://blogs.lt.vt.edu/ResearchBlog/#sthash.ZgBtKYWz.dpuf – See more at: http://blogs.lt.vt.edu/ResearchBlog/#sthash.q8nNKmH3.dpuf