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Sample records for pigmi

  1. PIGMI technology

    International Nuclear Information System (INIS)

    Swenson, D.A.

    1980-01-01

    The accelerator technologies relevant to the design of a medically practical pion generator for medical irradiations (PIGMI) have been identified and developed. A base-case design for PIGMI is presented here. The accelerator portion of the PIGMI facility consists of an injector, an rf quadrupole linac structure, a drift-tube linac structure, a coupled-cavity linac structure, 1 440-MHz rf system, six 1320-MHz rf systems, and a control and instrumentation system. Each of these components is described in some detail. A 100-μA, 650-MeV proton beam is anticipated. 24 figures, 2 tables

  2. PIGMI mechanical fabrication

    International Nuclear Information System (INIS)

    Hart, V.E.

    1976-01-01

    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. The following discussion deals with the modeling program that LASL is pursuing for 450-MHz and 1350-MHz PIGMI development. (author)

  3. Low-energy linac structure for PIGMI

    International Nuclear Information System (INIS)

    Swenson, D.A.; Stovall, J.E.

    1977-01-01

    The higher radio frequency (450 MHz) and lower injection energy (250 keV) of the PIGMI (Pion Generator for Medical Irradiations) linac design seriously compound the problem of beam containment in the first few meters of the structure. The conventional quadrupole-focused, drift-tube linac represents the best solution for beam energies above 8 MeV, but because of the small space available for quadrupoles in the PIGMI designs, cannot provide the required focusing at lower energies. A satisfactory solution to this focusing problem has been found based on pure alternating phase focusing for the first few MeV, followed by a smooth transition to a pure permanent magnet quadrupole-focused structure at 8 MeV. The structure and its calculated performance are described

  4. Initial performance of the PIGMI prototype

    International Nuclear Information System (INIS)

    Stovall, J.E.

    1979-01-01

    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

  5. Accelerating and focusing structures for PIGMI

    International Nuclear Information System (INIS)

    Swenson, D.A.; Bush, E.D. Jr.; Holsinger, R.F.; Manca, J.J.; Saito, N.; Stovall, J.E.

    1977-01-01

    The National Cancer Institute is supporting a program of accelerator development at the Los Alamos Scientific Laboratory aimed at the extension of proton linac technologies to produce the most suitable Pion Generator for Medical Irradiations (PIGMI). An optimized design of a pion generator suitable for a radiotherapy program at a major medical center has been established, consisting of a 250-keV injector, followed by a 35-meter-long drift-tube linac that accelerates the proton beam to 150 MeV, and an 85-meter-long coupled-cavity linac that accelerates the beam to its final energy of 650 MeV, where the average beam current of 100 microamperes impinges on one or more targets producing abundant quantities of π - mesons for radiotherapeutic applications. A number of extensions to proton linac technology are being pursued under the PIGMI program at LASL. A discussion is given of recent developments in three areas relevant to the acceleration and focusing of proton beams, namely, the alternating phase focused (APF) linac structure, the disk and washer linac structure, and small permanent magnet quadrupole lenses. The APF linac structure is being developed for the acceleration and focusing role from the injection energy of 250 keV to a few MeV, where a transition is made to a permanent magnet quadrupole focused linac structure. The disk and washer linac structure is under consideration for the high velocity portion of the design

  6. PIGMI program at the Los Alamos Scientific Laboratory

    International Nuclear Information System (INIS)

    Stovall, J.E.

    1980-09-01

    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

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

    International Nuclear Information System (INIS)

    Hansborough, L.D.

    1981-09-01

    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 100-μA 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

  8. Advantages of combining an EBIS with the PIGMI technology

    International Nuclear Information System (INIS)

    Hamm, R.W.

    1980-01-01

    The Electron Beam Ion Source (EBIS) produces highly charged heavy ions by electron impact ionization of ions electrostatically trapped within a dense energetic electron beam. Because of its pulsed operation and the highly charged ions produced, the EBIS is ideally suited as an injector for a high-gradient, low duty-cycle linac such as that being developed at the Los Alamos Scientific Laboratory (LASL) in the program to design a Pion Generator for Medical Irradiation (PIGMI). This combination of new technologies would produce an efficient, small heavy ion linac useful in a variety of research and practical applications

  9. PIGMI linear-accelerator technology

    International Nuclear Information System (INIS)

    Boyd, T.J.; Crandall, K.R.; Hamm, R.W.

    1981-01-01

    A new linear-accelerator technology has been developed that makes pi-meson (pion) generation possible for cancer therapy in the setting of a major hospital center. This technology uses several new major inventions in particle accelerator science-such as a new accelerator system called the radio-frequency quadrupole (RFQ), and permanent-magnet drift-tube focusing-to substantially reduce the size, cost, and complexity of a meson factory for this use. This paper describes this technology, discusses other possible uses for these new developments, and finally discusses possible costs for such installations

  10. Compact 250-kV injector system for PIGMI

    International Nuclear Information System (INIS)

    Hamm, R.W.; Stevens, R.R. Jr.; Mueller, D.W.; Lederer, H.M.

    1978-01-01

    A 250-kV proton injector to be used in the development of a linac suitable for medical applications has been constructed. This injector utilizes a spherical Pierce geometry to produce a converging beam. A gas insulated accelerating column is cantilevered on a grounded vacuum system, with a separate high voltage equipment dome connected to a 300-kV Cockcroft-Walton power supply. The injector can be operated locally or remotely, with the remote control accomplished by a microprocessor system linked to a central control minicomputer. This injector has been designed as a low-cost compact system. The design details and the data obtained during initial operation are presented

  11. Development of the new gamma-ray calorimeter for the measurement of Pigmy Dipole Resonance

    Science.gov (United States)

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

    2014-09-01

    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.

  12. 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

    2008-01-01

    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.

  13. Microprocessor-based stepping motor driver

    International Nuclear Information System (INIS)

    Halbig, J.K.; Klosterbuer, S.F.

    1979-09-01

    The Pion Generation for Medical Irradiations (PIGMI) program at the Los Alamos Scientific Laboratory requires a versatile stepping motor driver to do beam diagnostic measurements. A driver controlled by a microprocessor that can move eight stepping motors simultaneously was designed. The driver can monitor and respond to clockwise- and counterclockwise-limit switches, and it can monitor a 0- to 10-V dc position signal. The software controls start and stop ramping and maximum stepping rates. 2 figures, 1 table

  14. Vacuum design for the disk-and-washer accelerator structure

    International Nuclear Information System (INIS)

    Ruhe, J.R.; Hansborough, L.D.

    1982-02-01

    The disk-and-washer (DAW) accelerator structure is being developed for several applications. Because of its complicated geometry and newness, vacuum calculations for the DAW accelerator structure are not yet formalized. The applicable vacuum equations for this structure are presented and correlations for it have been made with the vacuum data from the Clinton P. Anderson Meson Physics Facility side-coupled accelerator structure. A calculation is presented for the DAW structure proposed for the Pion Generator for Medical Irradiations (PIGMI) accelerator

  15. Data acquisition and command system for use with a microprocessor-based control chassis

    International Nuclear Information System (INIS)

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

    1980-01-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, E. (comp.)

    1977-06-01

    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)

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

    International Nuclear Information System (INIS)

    Dunn, E.

    1977-06-01

    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

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

    OpenAIRE

    Barros, Maria Claudene; Sampaio, Iracilda; Schneider, Horacio

    2008-01-01

    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...

  19. Accelerator technology program. Progress report, July-December 1980

    International Nuclear Information System (INIS)

    Knapp, E.A.; Jameson, R.A.

    1982-01-01

    The activities of Los Alamos National Laboratory's Accelerator Technology Division are discussed. This report covers the last six months of calendar 1980 and is organized around the Division's major projects. These projects reflect a wide variety of applications and sponsors. The major technological innovations promoted by the Pion Generator for Medical Irradiation (PIGMI) program have been developed; accelerator technologies relevant to the design of a medically practical PIGMI have been identified. A new group in AT Division deals with microwave and magnet studies; we describe the status of some of their projects. We discuss the prototype gyrocon, which has been completed, and the development of the radio-frequency quadrupole linear accelerator, which continues to stimulate interest for many possible applications. One section of this report briefly describes the results of a design study for an electron beam ion source that is ideally suited as an injector for a heavy ion linac; another section reports on a turbine engine test facility that will expose operating turbine engines to simulated maneuver forces. In other sections we discuss various activities: the Fusion Materials Irradiation Test program, the free-electron laser program, the racetrack microtron project, the Proton Storage ring, and H - ion sources and injectors

  20. Long-pulse applications of pulse-forming lines for high-power linac application

    International Nuclear Information System (INIS)

    Hoeberling, R.F.; Tallerico, P.J.

    1981-01-01

    The ever present demands for high efficiency in the RF power stations for particle accelerators have caused increased interest in longer RF pulses (ten's of microseconds) for linacs such as the Pion Generator for Medical Irradiation (PIGMI) and Free Electron Laser (FEL). For either RF power station, a fundamental decision is whether to use a modulating anode/hard-tube driver or pulsed cathode/line-type pulser configuration. The choices in the extremes of low power for very long pulses or for very-high-power, short pulses are, respectively, a modulated anode/hard tube modulator and pulsed cathode/pulse forming line. However, the demarcation between these two extremes is not clearcut. The criteria (cost, flexibility performance, reliability, efficiency) that resulted in the RF station definition of these two specific systems will be described

  1. General-purpose microprocessor-based control chassis

    International Nuclear Information System (INIS)

    Halbig, J.K.; Klosterbuer, S.F.; Swenson, D.A.

    1979-12-01

    The objective of the Pion Generation for Medical Irradiations (PIGMI) program at the Los Alamos Scientific Laboratory is to develop the technology to build smaller, less expensive, and more reliable proton linear accelerators for medical applications. For this program, a powerful, simple, inexpensive, and reliable control and data acquisition system was developed. The system has a NOVA 3D computer with a real time disk-operating system (RDOS) that communicates with distributed microprocessor-based controllers which directly control data input/output chassis. At the heart of the controller is a microprocessor crate which was conceived at the Fermi National Accelerator Laboratory. This idea was applied to the design of the hardware and software of the controller

  2. Particle-beam accelerators for radiotherapy and radioisotopes

    International Nuclear Information System (INIS)

    Boyd, T.J.; Crandall, K.R.; Hamm, R.W.

    1981-01-01

    The philosophy used in developing the new PIGMI technology was that the parameters chosen for physics research machines are not necessarily the right ones for a dedicated therapy or radioisotope machine. In particular, the beam current and energy can be optimized, and the design should emphasize minimum size, simplicity and reliability of operation, and economy in capital and operating costs. A major part of achieving these goals lay in raising the operating frequency and voltage gradient of the accelerator, which shrinks the diameter and length of the components. Several other technical innovations resulted in major system improvements. One of these is a radically new type of accelerator structure named the radio-frequency quadrupole (RFQ) accelerator. This allowed us to eliminate the large, complicated ion source used in previous ion accelerators, and to achieve a very high quality accelerated beam. Also, by using advanced permanent magnet materials to make the focusing elements, the system becomes much simpler. Other improvements have been made in all of the accelerator components and in the methods for operating them. These will be described, and design and costing information examples given for several possible therapy and radioisotope production machines

  3. Electromagnetic moments and electric dipole transitions in carbon isotopes

    International Nuclear Information System (INIS)

    Suzuki, Toshio; Sagawa, Hiroyuki; Hagino, Kouichi

    2003-01-01

    We carry out shell model calculations to study electromagnetic moments and electric dipole transitions of C isotopes. We point out the configuration dependence of the quadrupole and magnetic moments of 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 also study the electric dipole states of C isotopes, focusing on the interplay between low energy pigmy strength and giant dipole resonances. As far as the energies of the resonances are concerned, reasonable agreement is obtained with available experimental data for the photoreaction cross sections in 12 C, 13 C, and 14 C, both in the low energy region below (ℎ/2π)ω=14 MeV and in the high energy giant resonance region (14 MeV 15 C is found to exhaust about 12-16 % of the classical Thomas-Reiche-Kuhn sum rule value and 50-80 % of the cluster sum rule value

  4. Accelerator technology program. Progress report, January-June 1981

    International Nuclear Information System (INIS)

    Knapp, E.A.; Jameson, R.A.

    1982-05-01

    This report covers the activities of Los Alamos National Laboratory's Accelerator Technology Division during the first 6 months of calendar 1981. We discuss the Division's major projects, which reflect a variety of applications and sponsors. The varied technologies concerned with the Proton Storage ring are concerned with the Proton Storage Ring are continuing and are discussed in detail. For the racetrack microtron (RTM) project, the major effort has been the design and construction of the demonstration RTM. Our development of the radio-frequency quadrupole (RFQ) linear accelerator continues to stimulate interest for many possible applications. Frequent contacts from other laboratories have revealed a wide acceptance of the RFQ principle in solving low-velocity acceleration problems. In recent work on heavy ion fusion we have developed ideas for funneling beams from RFQ linacs; the funneling process is explained. To test as many aspects as possible of a fully integrated low-energy portion of a Pion generator for Medical Irradiation (PIGMI) Accelerator, a prototype accelerator was designed to take advantage of several pieces of existing accelerator hardware. The important principles to be tested in this prototype accelerator are detailed. Our prototype gyrocon has been extensively tested and modified; we discuss results from our investigations. Our work with the Fusion Materials Irradiation Test Facility is reviewed in this report

  5. Preliminary study of possible ORELA replacement options

    International Nuclear Information System (INIS)

    Olsen, D.K.; Martin, J.A.; Horen, D.J.

    1984-06-01

    Based on two conceptual design studies performed by the LANL Accelerator Technology Division, the possibilities in terms of accelerator systems for replacing ORELA with a more intense Maxwellian-type continuous-energy neutron source are summarized and discussed. The neutron intensities from ORELA are compared with those from existing or potential accelerator systems used for cross-section and condensed-matter studies. The best replacement options seem to involve a spallation source from 200- to 400-MeV protons on an ORELA-like target. Pulsing and intensity desiderata with such a source are discussed which correspond to a spectrum-averaged 100-fold improved figure of merit over ORELA for TOF measurements with only a tenfold increased source strength. Existing accelerator designs seem to be inadequate for such a source. Consequently, two conceptual designs were developed for this study by the LANL Accelerator Technology Division. The first conceptual design is for a 200-MeV large linac capable of accelerating 1.3 A during a macropulse; this linac standing alone could serve as an ORELA replacement source. The second conceptual design is for a much smaller 250-MeV PIGMI linac with a 28-mA macropulse current which feeds a proton accumulator ring and bunch-compressor transport line. This linac-ring-compressor (LIRIC) option would give a more cost-effective neutron source for cross-section measurements, whereas the large linac, or a modified version of it, would give a much simpler system more suitable for expansion. In particular, both conceptual designs would incorporate the present ORELA building and would provide approximately 100-fold improved neutron sources over ORELA for cross-section measurements. The total estimated cost of the LIRIC system would be $43M (1984), whereas the cost of the large linac would be about a factor of two more. 55 references, 11 figures, 19 tables

  6. Accelerator technology program. Progress report, July-December 1981

    International Nuclear Information System (INIS)

    Knapp, E.A.; Jameson, R.A.

    1982-08-01

    We report on the major projects of the Los Alamos National Laboratory's Accelerator Technology Division during the last 6 months of calendar year 1981. We have continued work on the radio-frequency quadrupole linear accelerator; we are doing studies of octupole focusing. We have completed the design study on an unusual electron-linear radiographic machine that could obtain x rays of turbine engines operating under simulated flight-maneuver conditions on a centrifuge. In September we completed the 5-y PIon Generator for Medical Irradiation (PIGMI) program to develop the concept and technology for an accelerator-based facility to treat cancer in a hospital environment. The design and construction package for the site, building, and utilities for the Fusion Materials Irradiation Test (FMIT) facility has been completed, and we have begun to concentrate on tests of the rf power equipment and on the design, procurement, and installation of the 2-MeV proto-type accelerator. The Proton Storage Ring project has continued to mature. The main effort on the racetrack microtron (RTM) has been on the design and construction of various components for the demonstration RTM. On the gyrocon radio-frequency generator project, the gyrocon was rebuilt with a new electron gun and new water-cooled gun-focus coil; these new components have performed well. We have initiated a project to produce a klystron analysis code that will be useful in reducing the electrical-energy demand for accelerators. A free-electron laser amplifier experiment to test the performance of a tapered wiggler at high optical power has been successfully completed

  7. Patterns of circulating corticosterone in a population of rattlesnakes afflicted with snake fungal disease: Stress hormones as a potential mediator of seasonal cycles in disease severity and outcomes

    Science.gov (United States)

    Lind, Craig M.; Moore, Ignacio T.; Akçay, Çağlar; Vernasco, Ben J.; Lorch, Jeffrey M.; Farrell, Terence M.

    2018-01-01

    Snake fungal disease (SFD) is an emerging threat to snake populations in the United States. Fungal pathogens are often associated with a physiological stress response mediated by the hypothalamo-pituitary-adrenal axis (HPA), and afflicted individuals may incur steep coping costs. The severity of SFD can vary seasonally; however, little is known regarding (1) how SFD infection relates to HPA activity and (2) how seasonal shifts in environment, life history, or HPA activity may interact to drive seasonal patterns of infection severity and outcomes. To test the hypothesis that SFD is associated with increased HPA activity and to identify potential environmental or physiological drivers of seasonal infection, we monitored baseline corticosterone, SFD infection severity, foraging success, body condition, and reproductive status in a field-active population of pigmy rattlesnakes. Both plasma corticosterone and the severity of clinical signs of SFD peaked in the winter. Corticosterone levels were also elevated in the fall before the seasonal rise in SFD severity. Severely symptomatic snakes were in low body condition and had elevated corticosterone levels compared to moderately infected and uninfected snakes. The monthly mean severity of SFD in the population was negatively related to population-wide estimates of body condition and temperature measured in the precedent month and positively correlated with corticosterone levels measured in the precedent month. Symptomatic females were less likely to enter reproductive bouts compared to asymptomatic females. We propose the hypothesis that the seasonal interplay among environment, host energetics, and HPA activity initiates trade-offs in the fall that drive the increase in SFD prevalence, symptom severity, and decline in condition observed in the population through winter.

  8. Radio-frequency quadrupole: a new linear accelerator

    International Nuclear Information System (INIS)

    Stokes, R.H.; Wangler, T.P.; Crandall, K.R.

    1981-01-01

    In many Laboratories, great emphasis now is placed on the development of linear accelerators with very large ion currents. To achieve this goal, a primary concern must be the low-velocity part of the accelerator, where the current limit is determined and where most of the emittance growth occurs. The use of magnetic focusing, the conflicting requirements in the choice of linac frequency, and the limitations of high-voltage dc injectors, have tended to produce low-velocity designs that limit overall performance. The radio-frequency quadrupole (RFQ) linear accelerator, invented in the Soviet Union and developed at Los Alamos, offers an attractive solution to many of these low-velocity problems. In the RFQ, the use of RF electric fields for radial focusing, combined with special programming of the bunching, allows high-current dc beams to be captured and accelerated with only small beam loss and low radial emittance growth. Advantages of the RFQ linac include a low injection energy (20 to 50 keV for protons) and a final energy high enough so the beam can be further accelerated with high efficiency in a Wideroee or Alvarez linac. These properties have been confirmed at Los Alamos in a highly successful experimental test performed during the past year. The success of this test and the advances in RFQ design procedures have led to the adoption of this linac for a wide range of applications. The beam-dynamics parameters of three RFQ systems are described. These are the final design for the protytype test of the Fusion Materials Irradiation Test (FMIT) accelerator, the final design for the prototype test of the Pion Generator for Medical Irradiations (PIGMI), and an improved low-velocity linac for heavy ion fusion

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

    Science.gov (United States)

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

    2017-08-01

    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.

  10. Ocorrência de Giardia, Cryptosporidium e microsporídios em animais silvestres em área de desmatamento no Estado de São Paulo, Brasil Occurrence of Giardia, Cryptosporidium and microsporidia in wild animals from a deforestation area in the state of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Maria Anete Lallo

    2009-08-01

    municipalities of Mogi das Cruzes, Salesópolis and Biritiba-Mirim, in the state of São Paulo (Brazil. Samples were obtained from 46 rodents, 21 marsupials, 16 frogs, 9 bats, 3 tamarins and 3 lizards. For the detection of Giardia, Cryptosporidium and microsporidia it was used, respectively, the floatation technique with lead sulphate, the Kinyoun method and the Gram-Chromotrope staining. The total number of parasitized animals by one of these protozoans was 17.35% (17/98. Cysts of Giardia were found in faecal samples from 2 prehensile-tailed porcupines (Coendou villosus. The three positive animals for Cryptoporidium were rodents - 1 montane akodont (Akodon montensis, 1 ebony akodont (Thaptomyces nigrita and 1 guainan squirrel (Sciurus aestuans. Microporidia spores were seen in the stools of 12 animals - 6 small rodents, including 3 montane akodonts, 1 prehensile-tailed porcupine and 2 pigmy rice rats (Oligoryzomys sp.; 3 marsupials, including 1 gray slender mouse opossum (Marmosops incanus and 2 big eared opossums (Didelphis aurita; 3 hairy-legged vampire bats (Diphylla ecaudata. This is the first description of microsporidiosis in wildlife animals in Brazil. The present study emphasizes the importance of these animals, particularly small mammals, as potential sources of protozoan infection to other animal populations, including man, in areas of deforestation.