Sample records for pigmi

  1. Pigmi mechanical fabrication. [Pion Generator for Medical Irradiations (PIGMI)

    Energy Technology Data Exchange (ETDEWEB)

    Hart, V.E.


    A prime goal of the mechanical design effort associated with the PIGMI (Pion Generator for Medical Irradiations) program is to investigate new materials and fabrication techniques in an effort to obtain increased machine efficiency and reliability at a reasonable cost. A discussion is given dealing with the modeling program that LASL is pursuing for 450-MHz and 1350-MHz PIGMI development.

  2. Optimized design for PIGMI

    Energy Technology Data Exchange (ETDEWEB)

    Hansborough, L.; Hamm, R.; Stovall, J.; Swenson, D.


    PIGMI (Pion Generator for Medical Irradiations) is a compact linear proton accelerator design, optimized for pion production and cancer treatment use in a hospital environment. Technology developed during a four-year PIGMI Prototype experimental program allows the design of smaller, less expensive, and more reliable proton linacs. A new type of low-energy accelerating structure, the radio-frequency quadrupole (RFQ) has been tested; it produces an exceptionally good-quality beam and allows the use of a simple 30-kV injector. Average axial electric-field gradients of over 9 MV/m have been demonstrated in a drift-tube linac (DTL) structure. Experimental work is underway to test the disk-and-washer (DAW) structure, another new type of accelerating structure for use in the high-energy coupled-cavity linac (CCL). Sufficient experimental and developmental progress has been made to closely define an actual PIGMI. It will consist of a 30-kV injector, and RFQ linac to a proton energy of 2.5 MeV, a DTL linac to 125 MeV, and a CCL linac to the final energy of 650 MeV. The total length of the accelerator is 133 meters. The RFQ and DTL will be driven by a single 440-MHz klystron; the CCL will be driven by six 1320-MHz klystrons. The peak beam current is 28 mA. The beam pulse length is 60 at a 60-Hz repetition rate, resulting in a average beam current. The total cost of the accelerator is estimated to be approx. $10 million.

  3. Pigmy resonances, transfer, and separable potentials

    CERN Document Server

    Bertulani, C A; Kruppa, A; Hao, T V Nhan; Mukhamedzhanov, A M; Shubhchintak,


    In this contribution we make a short review of recent progress on topics of current interest in nuclear physics and nuclear astrophysics. In particular, we discuss a re-analysis of the extraction of the dipole response of the pigmy resonance in $^{68}$Ni based on a continuum discretized coupled-channels calculation in relativistic Coulomb excitation experiments. We also discuss the forthcoming progresses made by our group on the Alt-Sandhas-Grassberber approach to (d,p) reactions and future expectations. The role of separable potentials in solving such equations with a test case based on applications of such potentials to phase-shift analysis is also presented.

  4. PIGMI program at the Los Alamos Scientific Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, J.E.


    The PIGMI Program has completed 3-1/2 yr of a project to develop the technology for the optimal pion generator for medical irradiations (PIGMI). The major accomplishments under the program include completion of the injector beam measurements; completion of the 440-MHz radio-frequency (rf) power source; assembly and test of the alternating phase focusing accelerator section; development of the rf-quadrupole (RFQ) beam-dynamics program, PARMTEQ; design, fabrication, assembly, and test of the RFQ accelerator; final decision on low-energy configuration for PIGMI; assembly of the drift-tube linac section of the PIGMI Prototype; completion of sample set of permanent magnet quadrupoles; optimization of the disk-and-washer (DAW) cavity geometry; fabrication of model cavities of the DAW; final decision on DAW support geometry; acquisition of additional laboratory space for the DAW power test; partial assembly of the 1320-MHz rf power source for the DAW test; and pion channel design studies.

  5. Mechanical technologies for PIGMI. [Pion Generator for Medical Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Hansborough, L.D.


    PIGMI (Pion Generator for Medical Irradiations) is a compact linear proton accelerator designed for a hospital environment. The prototype of the low energy section of PIGMI has been designed and is being fabricated at the Los Alamos Scientific Laboratory. It is an accelerator design which makes use of several advanced or innovative technologies. The PIGMI Prototype consists of a 250 keV injector, a double harmonic buncher, a tape-wound 13 KG solenoid magnet, and four accelerator tanks with a total of 63 drift tubes of which 18 contain strong focusing quadrupoles of permanent magnets. The accelerator tanks are mild steel, copper-plated using a bright acid leveling technique. Drift tubes are stainless steel, fabricated using electron beam welding, shaped in a lathe and then copper plated. Drift tubes loaded with permanent magnets are sealed using laser welding. The samarium cobalt magnets are shaped by cutting and grinding techniques developed at Los Alamos.

  6. PIGMI: a design report for Pion Generator for Medical Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Hansborough, L.D. (comp.)


    PIGMI (Pion Generator for Medical Irradiations) is an integrated linear accelerator (linac) system developed under the auspices of the National Cancer Institute for specific application to cancer treatment in a hospital environment. In its full configuration, PIGMI is a proton linac that is far smaller, less expensive, and more reliable than previous machines that produce pions. Subsets of PIGMI technology can be used with equal advantage to generate beams of other particles (such as neutrons, protons, or heavy ions) that may be of interest for radiotherapy, radioisotope production, or other applications. The dramatic performance and cost advantages of this new breed of acceleraor result from a number of improvements. In the low-energy portion of the machine, a new type of low-energy linac (the radio-frequency quadrupole(RFQ)) produces an exceptionally good quality beam, and uses a very simple 30-kV injector. In the second part of the machine (the drift-tube linac (DTL)), high accelerating gradients are now achievable with consequent reductions in machine length. Another new structure (the disk and washer (DAW)) will be used in the third and final section of the accelerator; this portion will also be relatively short and require few power amplifiers. The entire machine is designed for ease of operation and high reliability. The pion-production machine, discussed in this report, accelerates a average proton-beam current to 650 MeV; use of an efficient pion-collection channel would result in an average pion flux of over 100 rad/min in a volume of about 1 l. Pion-channel design is not treated in this report. Accelerator construction cost is estimated at $10 million (1980 dollars); site preparation and treatment facility costs would bring the cost of a complete facility to an estimated $25 million.

  7. Initial performance of the PIGMI prototype. [Pion Generator for Medical Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, J.E.


    The PIGMI (Pion Generator for Medical Irradiations) program at LASL is an accelerator development program aimed at completing the design of an accelerator suitable for use as a pion generator in a hospital-based radiotherapy program. The major thrust of the program has been the design of a 7 MeV prototype accelerator which emphasizes compactness, economy of construction, and operation and reliability. To achieve these goals the design of the prototype has exploited a number of innovations in proton linac technology. An overview of the program discussing the major innovative features of the prototype is presented. The initial operating experience is discussed and initial performance measurements are presented.

  8. Data acquisition and command system for use with a microprocessor-based control chassis. [PIGMI-Pion Generation for Medical Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Halbig, J.K.; Klosterbuer, S.F.; Martinez, V.A. Jr.


    The Pion Generation for Medical Irradiations (PIGMI) program at the Los Alamos Scientific Laboratory is developing the technology to build smaller, less expensive, and more reliable proton linear accelerators for medical applications, and has designed a powerful, simple, inexpensive, and reliable control and data acquisition system that is central to the program development. The system is a NOVA-3D minicomputer interfaced to several outlying microprocessor-based controllers, which accomplish control and data acquisition through data I/O chasis. The equipment interface chassis, which can issue binary commands, read binary data, issue analog commands, and read timed and untimed analog data is described.

  9. Development of the new gamma-ray calorimeter for the measurement of Pigmy Dipole Resonance (United States)

    Shikata, Mizuki; Nakamura, Takashi; Togano, Yasuhiro; Kondo, Yosuke


    A new γ-ray calorimeter CATANA (CAlorimeter for gamma γ-ray Transition in Atomic Nuclei at high isospin Asynmetry) has been developed to measure highly excited states like the pygmy dipole resonance and the giant dipole resonance. CATANA will be used with the SAMURAI spectrometer at RIBF. The excitation energy spectrum will be reconstructed combining the invariant mass of the reaction products measured by SAMURAI and γ-ray energies from CATANA. CATANA has focused on achieving a high detection efficiency. It is calculated as 56% for 1 MeV γ-rays from beam with a velocity of β = 0.6. The CATANA array consists of 200 CsI(Na) crystals and covers angles from 10 to 120 degrees along the beam axis. In this study, we have tested prototype crystals of CATANA to evaluate their performance. A position dependence of the light input have been measured and compared with a Monte-Carlo simulation based on GEANT4. In this talk, we will report the design of CATANA and the result of the tests and the simulation.

  10. Shell Model Study on the Proton Pigmy Dipole Resonances in ~(17, 18)Ne

    Institute of Scientific and Technical Information of China (English)


    The proton pygmy dipole resonances (PDRs) in proton rich nuclei 17, 18Ne have been investigated in the framework of interacting shell model. The shell model with the self-consistent Skyrme-Hartree-Fock wave functions has well reproduced

  11. New record on Pigmy Field Mouse (muridae, rodentia from northeast Iran

    Directory of Open Access Journals (Sweden)

    Jamshid Darvish


    Full Text Available

    In this study the field mice of eastern Elborz in Golestan province were examined using molecular, morphologic and morphometric characters. RFLP analysis indicates the presence of three different haplotypes called as A, B and C. Taxonomic determination of the specimens of the haplotyes shows that haplotypes A, B and C represents three different species, A. cf. uralensis, A. cf. hyrcanicus and A. witherbeyi, respectively. Two latter species were previously reported from the studied area. However, the discovery of A. cf. uralensis in this region extends the eastern border of the distribution of this species up to eastern Elbruz and confirms the sympatric occurrence of A. uralensis and A. hyrcanicus in the Golestan province. 

  12. Draft Environmental Impact Statement. MX Deployment Area Selection and Land Withdrawal/Acquisition DEIS. Volume 3, Part II. Affected Environment. (United States)


    Astraglus geyeri var. triquetrus) and Nye milkvetch (A. yensis) occur within 2 mi of Moapa. The pigmy agave ( Agave utahensis var. eborispin ) occurs 5 mi...and green molly (Kochia americana ). Alkali sink scrub and shadscale are the predominant vegetation types in the Sevier Desert watershed. These two

  13. Environmental Impact Analysis Process. Deployment Area Selection and Land Withdrawal/Acquisition DEIS. Chapter III. Part II. Affected Environment. (United States)


    The pigmy agave ( Agave utahensis var. e-orispina) occurs 5 mi west of the OB, within the boundary of the Desert Game Range. Wilderness and...type are greasewood (Sarcobatus vermiculatus), and green molly (Kochia americana ). Alkali sink scrub and shadscale are the predominant vegetation types

  14. Do Invasive Fire Ants Affect Habitat Selection within a Small Mammal Community?

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    Wendee N. Holtcamp


    Full Text Available Animals must balance foraging with the need to avoid predators and risky habitats that decrease their fitness, and at the same time they must cope with competitors vying for habitat and resources. We examined how habitat selection and population density of four native small mammals were altered by the presence of red imported fire ants (Solenopsis invicta. When population size was low, hispid cotton rats (Sigmodon hispidus and pigmy mice (Baiomys taylori as well as white-footed mice (Peromyscus leucopus used the “safe”, low fire ant habitat, as predicted by theories of density-dependent habitat selection. However, as fire ant population sizes expanded, cotton rats appeared to displace pigmy mice into the fire ant-dense grassland drainage while white-footed mice (Peromyscus leucopus displaced all the other small mammals from low fire ant forest/brushland habitat.

  15. Novel 12S mtDNA findings in sloths (Pilosa, Folivora and anteaters (Pilosa, Vermilingua suggest a true case of long branch attraction

    Directory of Open Access Journals (Sweden)

    Maria Claudene Barros


    Full Text Available We sequenced 12S RNA mtDNA for the majority of the extant species of sloths and anteaters and compared our results with previous data obtained by our group using 16S RNA mtDNA in the same specimens and to GenBank sequences of the extinct giant sloth Mylodon. Our results suggest that pigmy-anteaters may be a case of the long-branch attraction phenomenon and also show the large genetic difference between the Amazonian and Atlantic forest three-toed sloths, contrasting with the small differences observed between the two non-Atlantic forest forms of sloths. These results have important implications for the taxonomy of sloths and anteaters and strongly suggest the placement of pigmy anteaters in their own family (Cyclopidae and raising the taxonomic status of Bradypus torquatus to a genus.

  16. サバ州キナバタンガン川流域におけるエコツーリズムの背景と実態 : 持続可能な自然保護・地域社会・観光の融合への模索 (研究ノート)


    海津, ゆりえ


    This research note aims to review of the background of Borneo study-eco tour by World Wildlife Foundation (WWF) since late 1990s at Kinabatangan river basin, Saba, Malaysia. Kinabatangan basin area is the place where is developed since 18th century by Asian countries, such as China and Japan. Most of wild forest are cut down and transferred into plantation under the development and it causes reduce of number of wild mammals such as Oran-Utang, Pigmy Elephant and other monkeys. WWF focused on ...

  17. Medium-energy physics program. Progress report, November 1, 1976--January 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, E. (comp.)


    Operations and research programs at the LAMPF Linac are reported for the period from November 1, 1976 through January 31, 1977. The contents include: (1) a summary and a list of recent publications; (2) engineering support; (3) accelerator support; (4) accelerator systems development; (5) injector systems; (6) electronic instrumentation and computer systems; (7) accelerator operations; (8) experimental areas; (9) beam line development; (10) large-spectrometer systems; (11) research; (12) nuclear chemistry; (13) practical applications of LAMPF; (14) the PIGMI program (Pion Generator for Medical Irradiations); and (15) management. (PMA)

  18. Cetacean diversity on the Parnaiba Delta, Maranhão state, northeastern Brazil. (United States)

    Magalhães, F A; Tosi, C H; Garri, R G; Chellappa, S; Silva, F L


    The increase in the research of cetacean surveys on the Brazilian coast has brought new data on the distribution of species never reported before. The present work reviews the current knowledge on cetaceans species and extends this knowledge with an analysis of cetaceans stranded in the Parnaiba Delta, on the coast of Maranhão State, Brazil. The studies on cetacean diversity on the coast of the Parnaíba Delta were made from August 2004 to August 2006. Fourteen strandings were reported, representing six distinct species, such as the estuarine dolphin (Sotalia guianensis), humpback whale (Megaptera novaeangliae), Bryde's whales (Balaenoptera edeni), dwarf minke whale (Balaenoptera acutorostrata), pigmy killer whale (Feresa attenuata), sperm whale (Physeter macrocephalus) and two specimens which have not yet been identified. The significant degree of cetacean diversity in the region shows that the Parnaíba Delta is, possibly, of an important area for cetacean studies in Brasil.

  19. Cetacean diversity on the Parnaiba Delta, Maranhão state, northeastern Brazil

    Directory of Open Access Journals (Sweden)

    FA. Magalhães

    Full Text Available The increase in the research of cetacean surveys on the Brazilian coast has brought new data on the distribution of species never reported before. The present work reviews the current knowledge on cetaceans species and extends this knowledge with an analysis of cetaceans stranded in the Parnaiba Delta, on the coast of Maranhão State, Brazil. The studies on cetacean diversity on the coast of the Parnaíba Delta were made from August 2004 to August 2006. Fourteen strandings were reported, representing six distinct species, such as the estuarine dolphin (Sotalia guianensis, humpback whale (Megaptera novaeangliae, Bryde's whales (Balaenoptera edeni, dwarf minke whale (Balaenoptera acutorostrata, pigmy killer whale (Feresa attenuata, sperm whale (Physeter macrocephalus and two specimens which have not yet been identified. The significant degree of cetacean diversity in the region shows that the Parnaíba Delta is, possibly, of an important area for cetacean studies in Brasil.

  20. Long-term complications of snake bites to the upper extremity. (United States)

    Cowin, D J; Wright, T; Cowin, J A


    The purpose of this study was to determine long-term complications of upper-extremity snake envenomations. The records of 73 patients, who were seen for snake bites were obtained; 46 of these patients had bites to the upper extremity, and 27 had bites to the lower extremity. These patients were graded according to the severity of the bite. The snakes involved were eastern diamondback rattlesnake, coral snake, pigmy rattlesnake, water moccasin, and unknown. Fourteen of the 46 patients receiving upper extremity bites were examined by a hand surgeon and an occupational hand therapist 1 to 3.2 years after their bite. Subjective pain data, range-of-motion, intrinsic, extrinsic, finger-flexion tightness, grip strength, pinch strength and objective sensory data were collected. Four patients had continued pain and tissue atrophy at the bite site. There were no long-term sequelae from a missed compartment syndrome.

  1. Beta Decay Half-lives and Delayed Neutron Emission of r-process Neutron-Rich nuclei in the vicinity of 78Ni (United States)

    Madurga, M.


    The region of neutron rich isotopes at and beyond the N=50 shell closure in the vicinity of ^78Ni has recently attracted major interest from experimental and theoretical nuclear physics community [1-4]. Moreover, as many nuclei in the region are predicted precursors of r-process nucleosynthesis, their most basic nuclear properties such as mass and beta decay half-life are required parameters in abundance calculations. The availability of hight purity and high quality radioactive beams of nuclei in this region at the Holifield Radioactive Ion Beam Facility has spurred a systematic campaign to study their properties through beta decay. Four new half-lives of ^82,83Zn, ^85Ga and ^86Ge were measured for the first time. The resulting values differ from the predictions of the Finite Range Droplet Model used in r-process abundance calculations. We presented a new model based on Density Functional Theory that correctly reproduced the new half-lives. The revised analysis of the rapid neutron capture process in low entropy environments with our new set of measured and calculated half-lives shows a significant redistribution of predicted isobaric abundances strengthening the yield of A > 140 nuclei. Continuing our effort to systematically understand decay properties in the region of beta-delayed neutron emission, 30 nuclei in the region were studied using the neutron energy Time-of-Flight detector VANDLE. Due to the shell structure in the region, most of the decay strength is expected to concentrate in states above neutron separation energy, in the so-called Pigmy Giant resonance. Precise knowledge of the position and strength of the resonance may help fine tune and develop existing models, with the aim of increasing their reliability beyond what can be experimentally measured. The data resulting from the experimental campaign at Holifield are still being analyzed. In a few species strong shell effects have already been identified and they will be presented. In particular

  2. Vasotocin receptor blockade disrupts maternal care of offspring in a viviparous snake, Sistrurus miliarius

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    Craig M. Lind


    Full Text Available Parental care is a complex social behavior that is widespread among vertebrates. The neuroendocrine regulation of parent-offspring social behavior has been well-described in mammals, and to a lesser extent, in birds and fish. However, little is known regarding the underlying mechanisms that mediate the expression of care behaviors in squamate reptiles. In mammalian model species and humans, posterior pituitary hormones of the oxytocin and vasopressin families mediate parental care behaviors. To test the hypothesis that the regulatory role of posterior pituitary neuropeptides is conserved in a viviparous squamate reptile, we pharmacologically blocked the vasotocin receptor in post-parturient pigmy rattlesnakes, Sistrurus miliarius, and monitored the spatial relationship between mothers and offspring relative to controls. Mothers in the control group demonstrated spatial aggregation with offspring, with mothers having greater post-parturient energy stores aggregating more closely with their offspring. Blockade of vasotocin receptors eliminated evidence of spatial aggregation between mothers and offspring and eliminated the relationship between maternal energetic status and spatial aggregation. Our results are the first to implicate posterior pituitary neuropeptides in the regulation of maternal behavior in a squamate reptile and are consistent with the hypothesis that the neuroendocrine mechanisms underlying social behaviors are broadly conserved among vertebrates.

  3. Distribution and coexistence of shrews in patchy landscapes: A field test of multiple hypotheses (United States)

    Mortelliti, Alessio; Boitani, Luigi


    Despite the important role of shrews (Soricomorpha: Soricidae) in the functioning of ecosystems, as predators and prey, the effects of habitat loss and fragmentation on this guild of mammals are still unclear. We studied the distribution of 5 species (the greater white toothed shrew Crocidura leucodon; the lesser white toothed shrew Crocidura suaveolens; the pigmy shrew Sorex minutus; the Appennine shrew Sorex samniticus and the Etruscan shrew Suncus etruscus) in a fragmented landscape in central Italy. Shrews were trapped with pitfall traps made from plastic water bottles, the number of traps increased with patch size. A total of 170 individuals, of 5 species of shrews were captured. Shrews were widely distributed in our study area, however patch occupancy was determined mainly by vegetation and geometrical characteristics of the patches. Our data supports the hypotheses that patterns of habitat selection and the dynamics of seasonal abundance (habitat and temporal partitioning between similarly sized species) reduce competitive pressure, thus allowing coexistence of shrews in relatively species-rich assemblages, for such small amounts of habitat. The most important outcome of our results is the crucial role played by vegetation structure in determining distribution patterns. These results strongly suggest that measurements of the vegetation structure of habitat patches should always be included as explanatory variables when studying the distribution of shrews in fragmented landscapes.

  4. Exotic Structure of Carbon Isotopes

    CERN Document Server

    Suzuki, T; Hagino, K; Suzuki, Toshio; Sagawa, Hiroyuki; Hagino, Kouichi


    We studied firstly the ground state properties of C-isotopes using a deformed Hartree-Fock (HF)+ BCS model with Skyrme interactions. Shallow deformation minima are found in several neutron$-$rich C-isotopes. It is shown also that the deformation minima appear in both the oblate and the prolate sides in $^{17}$C and $^{19}$C having almost the same binding energies. Secondly, we carried out shell model calculations to study electromagnetic moments and electric dipole transitions of the C-isotopes. We point out the clear configuration dependence of the quadrupole and magnetic moments in the odd C-isotopes, which will be useful to find out the deformations and the spin-parities of the ground states of these nuclei. We studied electric dipole states of C-isotopes focusing on the interplay between low energy Pigmy strength and giant dipole resonances. Reasonable agreement is obtained with available experimental data for the photoreaction cross sections both in the low energy region below $\\hbar \\omega $=14 MeV and ...

  5. Serologic evidence for human hantavirus infection in Peru. (United States)

    Castillo Oré, Roger M; Forshey, Brett M; Huaman, Alfredo; Villaran, Manuel V; Long, Kanya C; Kochel, Tadeusz J; Guevara, Carolina; Montgomery, Joel M; Alvarez, Carlos A; Vilcarromero, Stalin; Morrison, Amy C; Halsey, Eric S


    While human illness associated with hantavirus infection has been documented in many countries of South America, evidence for hantavirus transmission in Peru has been limited to the isolation of Rio Mamore virus from a pigmy mouse rat (Oligoryzomys microtis) in the Amazon city of Iquitos. To address the possibility of human hantavirus exposure in the region, we screened febrile patients reporting to health clinics in Iquitos from 2007 to 2010 for serological evidence of recent hantavirus infection. In addition, we conducted a serological survey for hantavirus-reactive IgG among healthy participants residing in Iquitos and rural areas surrounding the city. Through the febrile surveillance study, we identified 15 participants (0.3%; 15/5174) with IgM reactive to hantavirus (Andes virus) antigen, all with relatively mild, self-limited illness. From the cross-sectional serosurvey we found that 1.7% (36/2063) of residents of the Iquitos area had serum IgG reactive to one or more hantaviruses, with a higher prevalence in the urban population (2.2%, compared to 1.1% in rural areas). These results suggest that human infection with hantavirus has occurred in Peru.

  6. Comparative anatomy of the foramen ovale in the Suina. (United States)

    Macdonald, A A


    The structure of the foramen ovale from six species of Suina was studied using the scanning electron microscope. In each species, the foramen ovale, when viewed from the terminal part of the caudal vena cava had the appearance of a short tunnel. In the domestic pig (Sus scrofa), the wart hog (Phacochoerus aethiopicus) and the bush pig (Potamochoerus porcus) a fold of tissue projected from the caudal edge of the foramen ovale into the lumen of the left atrium. It constituted a large proportion of the tube, and its distal end was generally straight-edged. In some domestic pig hearts small holes were found in the fold, and single threads of tissue arose from its trailing edge. These were not found in specimens from the other pigs or from the collared peccary (Tayassu tajacu), which had a thin unfenestrated tissue fold ending in a straight edge. In both species of hippopotamidae, the hippopotamus (Hippopotamus amphibius) and the pigmy hippopotamus (Choeropsis liberiensis) the fold of tissue was tubular, with strands of tissue extending from the atrial wall to insert on the outer surface of its proximal half. This tube was orientated at an angle of approximately 90 degrees to the caudal vena cava. Its walls were unfenestrated proximally and fenestrated distally, the latter forming a network over the end of the tube. The knotted appearance of the fold after birth suggested that the strands of the network had shortened and coalesced.

  7. Melanophoromas and iridophoromas in reptiles. (United States)

    Heckers, K O; Aupperle, H; Schmidt, V; Pees, M


    Chromatophoromas are tumours of pigment-producing cells of the skin and are rarely reported in reptiles. These tumours are subclassified on the basis of the type of pigment. The present study characterizes chromatophoromas arising in 26 reptiles, including six snakes, 19 lizards and a tortoise. These include the first reports of melanophoromas in a yellow anaconda (Eunectes notaeus), pigmy rattlesnake (Sistrurus spp.), southern water snake (Nerodia fasciata), veiled chameleon (Chamaeleo calyptratus) and leopard gecko (Eublepharis macularius); the first reports of benign iridophoromas in a savannah monitor (Varanus exanthematicus), veiled chameleon and bearded dragon (Pogona vitticeps); and the first description of a malignant iridophoroma in a bearded dragon. Additionally, in three bearded dragons a 'mucinous' type of melanophoroma is described for the first time. Chromatophoromas generally arose from the skin of the body and head and ranged in size from 0.2 to 2.0cm in diameter. In six cases the animals were humanely destroyed immediately after diagnosis. Three further animals were humanely destroyed following recurrence of their tumour. Six of these nine reptiles had visceral metastases. Grossly, melanophoromas (n=20) were grey or black, while iridophoromas (n=6) were white in colour. Microscopically, most of the tumours were composed of spindle cells with varying pigmentation and 0-2 mitoses per 10 high power fields. Six of the 20 melanophoromas were classified as malignant due to the presence of intravascular tumour cells, visceral metastases, high pleomorphism and/or mitotic figures. Five of the six iridophoromas were classified as benign and the one malignant tumour was defined by the presence of intravascular tumour cells and visceral metastases. Immunohistochemically, melan A and S100 were coexpressed by all of the chromatophoromas.

  8. Ecological controls on the shell geochemistry of pink and white Globigerinoides ruber in the northern Gulf of Mexico: implications for paleoceanographic reconstruction (United States)

    Richey, Julie N.; Poore, Richard Z.; Flower, Benjamin P.; Hollander, David J.


    We evaluate the relationship between foraminiferal test size and shell geochemistry (δ13C, δ18O, and Mg/Ca) for two of the most commonly used planktonic foraminifers for paleoceanographic reconstruction in the subtropical Atlantic Ocean: the pink and white varieties of Globigerinoides ruber. Geochemical analyses were performed on foraminifera from modern core-top samples of high-accumulation rate basins in the northern Gulf of Mexico. Mg/Ca analysis indicates a positive relationship with test size, increasing by 1.1 mmol/mol (~ 2.5 °C) from the smallest (150–212 μm) to largest (> 500 μm) size fractions of G. ruber (pink), but with no significant relationship in G. ruber (white). In comparison, oxygen isotope data indicate a negative relationship with test size, decreasing by 0.6‰ across the size range of both pink and white G. ruber. The observed increase in Mg/Ca and decrease in δ18O are consistent with an increase in calcification temperature of 0.7 °C per 100 μm increase in test size, suggesting differences in the seasonal and/or depth distribution among size fractions. Overall, these results stress the necessity for using a consistent size fraction in downcore paleoceanographic studies. In addition, we compare downcore records of δ18O and Mg/Ca from pink and white G. ruber in a decadal-resolution 1000-year sedimentary record from the Pigmy Basin. Based on this comparison we conclude that pink G. ruber is calcifying in warmer waters than co-occurring white G. ruber, suggesting differences in the relative seasonal distribution and depth habitat of the two varieties.

  9. Atlantic small-mammal: a dataset of communities of rodents and marsupials of the Atlantic forests of South America. (United States)

    Bovendorp, Ricardo S; Villar, Nacho; de Abreu-Junior, Edson F; Bello, Carolina; Regolin, André L; Percequillo, Alexandre R; Galetti, Mauro


    The contribution of small mammal ecology to the understanding of macroecological patterns of biodiversity, population dynamics, and community assembly has been hindered by the absence of large datasets of small mammal communities from tropical regions. Here we compile the largest dataset of inventories of small mammal communities for the Neotropical region. The dataset reviews small mammal communities from the Atlantic forest of South America, one of the regions with the highest diversity of small mammals and a global biodiversity hotspot, though currently covering less than 12% of its original area due to anthropogenic pressures. The dataset comprises 136 references from 300 locations covering seven vegetation types of tropical and subtropical Atlantic forests of South America, and presents data on species composition, richness, and relative abundance (captures/trap-nights). One paper was published more than 70 yr ago, but 80% of them were published after 2000. The dataset comprises 53,518 individuals of 124 species of small mammals, including 30 species of marsupials and 94 species of rodents. Species richness averaged 8.2 species (1-21) per site. Only two species occurred in more than 50% of the sites (the common opossum, Didelphis aurita and black-footed pigmy rice rat Oligoryzomys nigripes). Mean species abundance varied 430-fold, from 4.3 to 0.01 individuals/trap-night. The dataset also revealed a hyper-dominance of 22 species that comprised 78.29% of all individuals captured, with only seven species representing 44% of all captures. The information contained on this dataset can be applied in the study of macroecological patterns of biodiversity, communities, and populations, but also to evaluate the ecological consequences of fragmentation and defaunation, and predict disease outbreaks, trophic interactions and community dynamics in this biodiversity hotspot. © 2017 by the Ecological Society of America.