Amorphous Blobs Research Articles

What We Understand

What We Understand Gloria L. Huang (bio) When the rooms were empty and the halls were dark, the lights on the machines still flickered like silent Morse codes communicating together. She was present when the noise transformed from loud chatter to muffled quiet, she was there when bags were slung over shoulders and phones were picked up for the long journey home. Unseen and invisible, she was the sentinel who watched over the change from day to night. During work hours, the offices were alive with color and purpose. Posters plastered across the walls encouraged the reader to take risks, move fast, break things. She could never understand this urge to stir the water, to cause waves. This craving to break things and start anew. The vast office spaces were filled with chairs that existed in different shapes, some of them soft amorphous blobs, others upside-down tops that rotated dizzily. The people who came to work reminded her of children playing dress-up. Arriving on bicycles and scooters, backpacks strapped over both shoulders, they were young and fresh-faced. They spoke to computer screens while walking nowhere on treadmills, holding expensive cups of coffees in their hands. One time, she unlocked a door to discover that the floor was a pit filled with plastic balls. On her good days, the place reminded her of the night markets from her youth. The same bustle and color, the same business frenzy unfolding around her. Yet the vendors at the night markets had a hunger in their eyes they couldn't hide, no matter how casually they pretended they didn't need the sale. The children in these offices – they were well-fed and soft, had known nothing of true hardship or struggle. Every evening, Rose – the name she placed on her job applications in brackets to appear more "American" – arrived to clean up after these working children. She would swipe through the turnstile with the identity card attached to her waistband. Though her identity card was meant to provide proof of her membership, she couldn't help feeling that it repeatedly failed at its task. She did not belong to this place, this life. Pushing her janitorial cart from space to space, Rose's mind would wander as she emptied plastic trash containers tucked under desks. Sometimes she would marvel at how much food was thrown away as she wiped counters in kitchens dotted around the offices, her mouth watering at the selection of organic snacks but knowing the treats were not for her. Sometimes she would glance at the computer screens, the ones that hadn't turned black. The screens were often filled with letters and numbers that made no sense to her, as though a child had mashed the buttons on the keyboard until the screen filled up. The fact that these combinations of symbols meant something, created something – it astonished her. Most of the time, she thought about Julia. Rose would move silently between the desks, leaving a trail of cleanliness in her wake like a tornado in reverse. Occasionally someone would look up from [End Page 44] packing away their belongings and flash a smile in Rose's direction. She would nod silently, avoiding direct eye contact unless they looked like Julia. So many of these young girls looked like Julia, with their silky black hair tied into ponytails, their tilted eyes magnified behind thick glasses. She often thought of Julia's childhood, when she was round-cheeked and still adoring of everything Rose did. "Mommy, look at me!" "Mommy, watch this!" Her childish voice repeated requests for attention until the sweetness became grating, a sugary treat that became sickly. Rose regretted her feelings of annoyance now, wished she could go back and kneel before Julia, giving her all the attention she craved. Sometimes she remembered Julia as a teenager, and the cold feeling that descended between them as Julia grew distant and scornful. Rose could never figure out how to reach her, didn't know how to traverse the choppy seas of age and language to bring her sarcastic American daughter back to shore. So she did the only thing she could think of to keep...

First Report of Endolithic Members of Rhodosorus marinus (Stylonematales, Rhodophyta) Growing Inside Rhodoliths Offshore Louisiana, Northwestern Gulf of Mexico

Endolithic, red unicells residing in the interior of Lithothamnion rhodoliths, collected offshore the NW Gulf of Mexico in mesophotic rhodolith beds at ~54-55 m depth and maintained in closed microcosms, were used to establish cultures following their isolation. These endolithic unicells subsequently developed into amorphous blobs of palmelloid cell colonies. Each cell contains unstacked, 2-5 lobed parietal chloroplasts, one prominent central pyrenoid, and have a thin or thick cell wall. Single cells, or cell clusters (in pairs, tetrads, or up to 12) are embedded inside an extracellular matrix whose boundaries remain closely appressed to neighboring cell clusters. Cell division by concavo-convex division resulted in hemispherical cells subsequently expanding in size. Plastid tufA, psbA and 16S rDNA sequence analyses confirmed that the colonies are Rhodosorus marinus Geitler. This is the first report of a red alga spending part of its life history endolithically inside biogenic rhodoliths.

Transparent Exopolymer Particles (TEP): an overlooked factor in the process of biofilm formation in aquatic environments

We hypothesize that transparent exopolymer particles (TEP), present in high concentrations in most sea and freshwaters, are critical agents for biofilm initiation and development in many natural and anthropogenic aquatic environments. These gel-like particles appear in many forms; amorphous blobs, clouds, sheets, filaments or clumps ranging in size from ~2 to ~200 µm. TEP are mostly polysaccharide, negatively charged, very sticky and are frequently colonized by bacteria. TEP may be considered a "planktonic" subgroup of exopolymeric substances (EPS), widely studied in biofilm research. Recognition of TEP involvement in biofilm formation has important implications for a comprehensive understanding of the complexities of this process in aquatic environments and may also contribute to the considerable efforts being made in the global water industry to mitigate the harmful effects of biofouling in water treatment and desalination plants.

Transparent Exopolymer Particles (TEP): an overlooked factor in the process of biofilm formation in aquatic environments

AbstractWe hypothesize that transparent exopolymer particles (TEP), present in high concentrations in most sea and freshwaters, are critical agents for biofilm initiation and development in many natural and anthropogenic aquatic environments. These gel-like particles appear in many forms; amorphous blobs, clouds, sheets, filaments or clumps ranging in size from ~2 to ~200 µm. TEP are mostly polysaccharide, negatively charged, very sticky and are frequently colonized by bacteria. TEP may be considered a "planktonic" subgroup of exopolymeric substances (EPS), widely studied in biofilm research. Recognition of TEP involvement in biofilm formation has important implications for a comprehensive understanding of the complexities of this process in aquatic environments and may also contribute to the considerable efforts being made in the global water industry to mitigate the harmful effects of biofouling in water treatment and desalination plants.

SPONGES RELY ON SILICATE FOR SUPPORT

![Figure][1] Listening to Werner Muller talk about sponges, there's no doubt about his boundless enthusiasm for these primitive creatures. Sponges may look simple, but Muller explains that they are not amorphous blobs of cells; like other creatures, sponges have a `Bauplan' or body design.

Mass transfer correlations for nonaqueous phase liquid dissolution from regions with high initial saturations

The application of existing correlations for nonaqueous phase liquid (NAPL) dissolution, which were developed in small, one‐dimensional columns, to larger‐scale, heterogeneous or multidimensional systems has shown the predicted dissolution behavior depends greatly on the correlation used. Variation among existing correlations is due to the system scale, NAPL‐water interfacial area, and the nature of mass transfer or hydrodynamic mechanisms that are lumped in the correlation. In this paper, new mass transfer correlation is developed using NAPL dissolution data from a small 2‐D experimental cell that contained a well‐characterized heterogeneous distribution of grain sizes. The new correlation can be used for quantifying NAPL dissolution rates over a wide range of NAPL saturations and aqueous phase velocities within the NAPL source zone. When incorporated in a finite difference transport model, the correlation provides reasonably good predictions for systems with initially high NAPL saturations that are then reduced through the dissolution process. It is shown that NAPL dissolution is slower in this case due to the larger amorphous blobs that result from preferential flow and dissolution pathways. These large blobs have significantly less surface area in comparison with small discrete blobs that result from capillary entrapment. In comparison with other published dissolution correlations, the slower mass transfer rate is characterized with a significantly higher exponent on the NAPL saturation term.

Shapes, surfaces and saccades

Saccadic localization of spatially extended objects requires the computation of a single saccadic landing position. What representation of the target guides saccades? Saccades were examined for various targets composed of dots to determine whether landing position corresponded to the center-of-gravity (average location) of the dots, the center-of-area of the shape, or the symmetric axis. Targets were composed of dots configured as outline drawings of circles, ellipses, cardioids, wiggly lines, or amorphous blobs. In some cases, dot spacing was varied, extraneous dot clusters were superimposed, or different distributions of dots inside the boundary were added. Quasi-random dot clusters without a well-defined contour were also studied. Instructions were to look at the target as a whole, and keep latency long enough to avoid compromising accuracy. Saccades landed with a high level of precision (S.D.s 7–10% of target eccentricity) near the center-of-area of the target shape, rather than at the center-of-gravity of the dots or on the symmetric axis. Landing position was unaffected by the spacing of dots along the boundary, the addition of dots within the boundary, or the addition of the extraneous dot clusters. When the target was a cluster of quasi-random dots, saccades landed closer to the center-of-area of the implied surface than to the average location of the dots. Overall, the positions of individual dots were important only insofar as the dots affected overall target shape. The results show that a representation of target shape guides saccades, rather than a more primitive representation of individual elements within the attended region.

Multiple Resolution Skeletons

This paper presents a new algorithm to compute skeletons of noisy images of objects which can be described as ``amorphous blobs.'' Such a requirement arose from our research to obtain a better understanding of the role of the pseudopod in leukocyte locomotion. It involves the modeling and detection of pseudopods which are by their nature nonrigid bodies appearing on the cell's surface membrane. By computing skeletons at different resolutions, a filtered version can be produced without violating the constraints imposed by the semantic knowledge of pseudopod morphology. The filtered version incorporates all the significant ``events'' that occur at the different resolutions. The resolution at which the shape is examined is related to the degree of smoothing, in that the lower the resolution gets, the higher the degree of smoothing. Skeleton branches that persist over several scales arise from convexities that are locally as well as globally significant. Their stability is related to their perceptual significance. Our approach is to combine an initial region centered description (skeleton) with a boundary analysis executed at different resolutions. Having computed the skeleton at different scales, we then use those computed at the lower resolutions as a measure of how global the underlying convexity is. Clearly the skeletons computed at higher resolutions represent the exact location and orientation of the underlying convexities.