184,566 research outputs found
GRAPE-5: A Special-Purpose Computer for N-body Simulation
We have developed a special-purpose computer for gravitational many-body
simulations, GRAPE-5. GRAPE-5 is the successor of GRAPE-3. Both consist of
eight custom pipeline chips (G5 chip and GRAPE chip). The difference between
GRAPE-5 and GRAPE-3 are: (1) The G5 chip contains two pipelines operating at 80
MHz, while the GRAPE chip had one at 20 MHz. Thus, the calculation speed of the
G5 chip and that of GRAPE-5 board are 8 times faster than that of GRAPE chip
and GRAPE-3 board. (2) The GRAPE-5 board adopted PCI bus as the interface to
the host computer instead of VME of GRAPE-3, resulting in the communication
speed one order of magnitude faster. (3) In addition to the pure 1/r potential,
the G5 chip can calculate forces with arbitrary cutoff functions, so that it
can be applied to Ewald or P^3M methods. (4) The pairwise force calculated on
GRAPE-5 is about 10 times more accurate than that on GRAPE-3. On one GRAPE-5
board, one timestep of 128k-body simulation with direct summation algorithm
takes 14 seconds. With Barnes-Hut tree algorithm (theta = 0.75), one timestep
of 10^6-body simulation can be done in 16 seconds.Comment: 19 pages, 24 Postscript figures, 3 tables, Latex, submitted to
Publications of the Astronomical Society of Japa
GRAPE-6: The massively-parallel special-purpose computer for astrophysical particle simulation
In this paper, we describe the architecture and performance of the GRAPE-6
system, a massively-parallel special-purpose computer for astrophysical
-body simulations. GRAPE-6 is the successor of GRAPE-4, which was completed
in 1995 and achieved the theoretical peak speed of 1.08 Tflops. As was the case
with GRAPE-4, the primary application of GRAPE-6 is simulation of collisional
systems, though it can be used for collisionless systems. The main differences
between GRAPE-4 and GRAPE-6 are (a) The processor chip of GRAPE-6 integrates 6
force-calculation pipelines, compared to one pipeline of GRAPE-4 (which needed
3 clock cycles to calculate one interaction), (b) the clock speed is increased
from 32 to 90 MHz, and (c) the total number of processor chips is increased
from 1728 to 2048. These improvements resulted in the peak speed of 64 Tflops.
We also discuss the design of the successor of GRAPE-6.Comment: Accepted for publication in PASJ, scheduled to appear in Vol. 55, No.
The application of pesticides to grape bunches
The application of pesticides to grape bunches is complicated by the different shapes and forms of the grape bunch during growth. Initially the grape bunch has a very porous structure, while in later stages the grapes are closely packed. We consider estimates of the flow velocity through the grape bunch, droplet density within the spray, probability of droplet impaction on a bunch or individual grape and the maximum size of drop that can adhere to a grape surface
Direct Simulation of Dense Stellar Systems with GRAPE-6
In this paper we describe the current status of the GRAPE-6 project to
develop a special-purpose computer with a peak speed exceeding 100 Tflops for
the simulation of astrophysical N-body problems. One of the main targets of the
GRAPE-6 project is the simulation of dense stellar systems. In this paper,
therefore, we overview the basic algorithms we use for the simulation of dense
stellar systems and their characteristics. We then describe how we designed
GRAPE hardwares to meet the requirements of these algorithms. GRAPE-6 will be
completed by the year 2001. As an example of what science can be done on
GRAPE-6, we describe our work on the galactic center with massive black holes
performed on GRAPE-4, the predecessor of GRAPE-6.Comment: 12 pages, to appear in Dynamics of Star Clusters and the Milky Way,
eds. R. Spurzem et al. (ASP Conference Series
Pseudoparticle Multipole Method: A Simple Method to Implement High-Accuracy Treecode
In this letter we describe the pseudoparticle multipole method (P2M2), a new
method to express multipole expansion by a distribution of pseudoparticles. We
can use this distribution of particles to calculate high order terms in both
the Barnes-Hut treecode and FMM. The primary advantage of P2M2 is that it works
on GRAPE. GRAPE is a special-purpose hardware for the calculation of
gravitational force between particles. Although the treecode has been
implemented on GRAPE, we could handle terms only up to dipole, since GRAPE can
calculate forces from point-mass particles only. Thus the calculation cost
grows quickly when high accuracy is required. With P2M2, the multipole
expansion is expressed by particles, and thus GRAPE can calculate high order
terms. Using P2M2, we implemented an arbitrary-order treecode on GRAPE-4.
Timing result shows GRAPE-4 accelerates the calculation by a factor between 10
(for low accuracy) to 150 (for high accuracy). Even on general-purpose
programmable computers, our method offers the advantage that the mathematical
formulae and therefore the actual program is much simpler than that of the
direct implementation of multipole expansion.Comment: 6 pages, 4 figures, latex, submitted to ApJ Letter
Lewiston Journal Article, Meat Inspection
Letter on the debate to regulate meat production under current state or federal inspection regulations.https://digitalcommons.usm.maine.edu/michaud-mailhot/1002/thumbnail.jp
Perineal hernia : retrospective study of contralateral hernia after unilateral surgery
Bakgrund: Det har föreslagits att perinealbrÄck hos hundar möjligtvis ska betraktas som en bilateral
företeelse istÀllet för unilateral. Det finns dock endast begrÀnsad mÀngd data med avseende pÄ risk
för kontralateral operation efter ÄtgÀrd av unilateralt brÄck.
Syfte: Hypotesen var att behov av operation pÄ kontralateral sida var sÀllsynt. MÄlet med studien
var att undersöka förekomsten av kontralateral operation efter ett unilateralt ingrepp hos hund diagnostiserad med och behandlad för unilateralt perinealbrÄck.
Metod och Material: En retrospektiv kohortstudie genomfördes dÀr en sökning gjordes pÄ debiteringskoder för operation av perinealbrÄck omfattande en period över tio Är. Journaler som identifierades i sökningen analyserades. Sökningen avgrÀnsades till operationer genomförda under Ären
2009â2018 vid universitetsdjursjukhuset i Uppsala, Sverige. Gruppering av hundarna genomfördes
frÄn grupp ett till fem, dÀr grupp ett bestod av de hundar med initialt enkelsidigt brÄck, grupp tvÄ
bestod av de initialt dubbelsidiga hundarna, grupp tre bestod av de hundar med tydligt brÄck pÄ ena
sidan och med mÄttligt brÄck pÄ motsatta sidan, grupp fyra bestod av de hundar med tydligt brÄck
pÄ ena sidan och ett lindrigt brÄck pÄ den motsatta sidan och grupp fem bestod av de hundar som
hade tydligt brÄck pÄ ena sidan men motsatta sidan hade inget utvecklat brÄck utan endast kommentar om bland annat försvagad muskulatur.
I en fördjupad analys kontaktades vissa av djurÀgarna till grupp ett, alltsÄ de hundarna med
endast initialt enkelsidigt perinealbrÄck, som inte hade nÄgon notering om försvagning i muskelvÀggen eller ett ytterligare brÄck pÄ den kontralaterala sidan. De djurÀgare dÀr informationen saknades,
om deras hund hade behövt uppsöka veterinÀrvÄrd pÄ grund av att ett kontralateralt brÄck uppstÄtt
eller ej, kontaktades. Metoderna som anvÀndes vid kontaktande av djurÀgarna var telefonsamtal och
SMS. FrÄgor som stÀlldes var bland annat om hunden hade utvecklat problem med den kontralaterala sidan och om det i sÄ fall hade behövts ÄtgÀrdas kirurgiskt samt Älder pÄ hunden vid uppkomst
av eventuella problem. Om hunden var avliden stÀlldes frÄgan om hunden avlidit till följd av perinealbrÄcket eller av annan orsak.
Resultat: Studien identifierade totalt 80 hanhundar. Grupp ett, initialt enkelsidigt brÄck, bestod
av 30 hundar. Grupp tvÄ, initialt dubbelsidiga brÄck, konstaterades hos 24 hundar. Grupp tre bestod
av tvÄ hundar som registrerades med tydligt brÄck pÄ ena sidan och mÄttligt brÄck pÄ den motsatta
sidan. Grupp fyra bestod av fem hundar som registrerades med tydligt brÄck pÄ ena sidan och lindrigt
brÄck pÄ motsatta sidan. Grupp fem bestod av 19 hundar som registrerades med tydligt brÄck pÄ ena
sidan och en journalanteckning att motsatta sidans muskulatur uppfattades som slapp eller mer eftergivlig, utifrÄn en subjektiv bedömning vid rektalpalpation. Totala antalet registrerade operationer
blev 98 varav 33 exklusive kastration och 65 inklusive kastration. 15 hundar opererades bilateralt i
tvÄ steg varav 14 av dem var registrerade som grupp 2, initial som dubbelsidiga brÄck, och en hund
registrerades i grupp 5, slapp muskulatur pĂ„ den motsatta sidan. MedelĂ„ldern vid operation av perinealbrĂ„ck var 8,3 Ă„r (3,9â14,8 Ă„r) och medelvikten var 18,2 kg (3,5â49 kg). Utvecklande av kontralaterala perinealbrĂ„ck hos initialt unilaterala brĂ„ck, grupp ett, sĂ„gs hos fem av 30 hundar. TvĂ„ av de
fem hundarna ÄtgÀrdades kirurgiskt och en hund behandlades konservativt och tvÄ avlivades pÄ
grund av det kontralaterala brÄcket. Av de i grupp ett, initialt enkelsidigt brÄck, som ej utvecklade
brÄck pÄ kontralaterala sidan blev tvÄ avlivade under operation, en hund avlivades efter tvÄ mÄnader
pÄ grund av Äterfall av brÄck pÄ samma sida och en hund avlivades fem mÄnader efter operationen
pÄ grund av annan orsak som inte hade med perinealbrÄcket att göra. Utöver dessa fyra hundar var
tiden frÄn operation till uppföljning angÄende kontralateralt brÄck hos grupp ett, initialt enkelsidiga,
Sammanfattning
mellan 11 mĂ„naderâ11,8 Ă„r och ett medelvĂ€rde pĂ„ fyra Ă„r efter operation. De fyra hundarna som
avlivades i samband med operation eller kort tid efter genomförd kirurgi valdes att i denna studie
exkluderas. Totalt kontaktades 19 djurÀgare via telefon och/eller med sms med standardiserade frÄgor varav 15 djurÀgare svarade via telefonsamtal, tvÄ djurÀgare endast via sms och tvÄ djurÀgare
svarade aldrig. Genom denna intervju identifierades tvÄ av de fem hundarna som utvecklade kontralateralt brÄck. De tvÄ hundar vars djurÀgare inte lyckades kontaktas exkluderades. Detta medförde
att fem hundar av de 24 hundar med initialt enkelsidigt perinealbrÄck, 20,8 %, utvecklade ett kontralateralt brÄck pÄ den motsatta sidan. Hos de hundar som hade brÄck pÄ ena sidan samt notering
om försvagad muskulatur pÄ motsatta sidan, grupp fem, behövde en hund uppsöka veterinÀrvÄrd
samt ÄtgÀrdas kirurgiskt pÄ grund av att ha utvecklat perinealbrÄck pÄ den motsatta sidan. Av de
hundar som var registrerade som grupp 2â5, avlivades tvĂ„ i samband med operation pĂ„ grund av
dÄlig prognos och en strax efter operation pÄ grund av komplikationer som krÀvde en ny operation.
Dessa tre hundar valdes Àven de att exkluderas dÄ de inte bedömdes ha chansen att kunna utveckla
ett kontralateralt perinealbrÄck. Ytterligare tvÄ hundar avlivades 2,3 Är och 4 Är efter operationen pÄ
grund av problem med den genomförda brÄckoperationen. Ytterligare fem hundar registrerades som
avlidna pĂ„ grund av annan orsak. En hund med initialt dubbelsidigt perinealbrĂ„ck, grupp tvĂ„, rekommenderades avlivning pĂ„ grund av tumörsjukdom. 23 hundar, i grupperna 2â5, hade ingen journalanteckning varken om avlivning eller om en ny operation hade genomförts pĂ„ den icke opererade
sidan.
Det medförde att i grupp 2â5 behövde en hund av 32 (50 hundar minus de 15 hundar som opererades i tvĂ„ steg, minus de tre avlidna hundarna som inte hade en chans att utveckla problem pĂ„
motsatta sidan, dÄ de avlivades under operation eller precis efter operationen) behövde uppsöka
veterinÀrvÄrd och ÄtgÀrdas kirurgiskt pÄ grund av problem med den motsatta sidan.
Det medför att av totalt 56 (24+32) enkelsidigt ÄtgÀrdade hundar sÄgs kontralateralt brÄck sammanlagt hos sex hundar, 10,7 %.
Diskussion: Resultaten av denna studie gav svagt eller inget stöd för rekommendationen att
perinealbrÄck bör opereras bilateralt, om hunden har enkelsidigt brÄck vid den kliniska undersökningen. Indikation gavs Àven att hundar som opererats enkelsidigt Àven fast de har lindrigt, mÄttligt
eller pÄbörjan till perinealbrÄck kontralateralt, inte behöver opereras bilateralt rutinmÀssigt. I denna
studie hittades fall dÀr operation senare utfördes pÄ den kontralaterala sidan, bÄde nÀr diagnosen
initialt var enkelsidigt brÄck eller en journalanteckning angÄende tecken pÄ försvagad muskelvÀgg
kontralateralt.
Studiens huvudbegrÀnsningar: Studien var retrospektiv och begrÀnsad till endast patientjournaler frÄn universitetsdjursjukhuset i Uppsala. Olika veterinÀrer gjorde undersökningarna och bedömningen om muskelvÀggen var intakt, eller försvagad, om förÀndringen klassades som lindrigt
brÄck eller fullt utvecklat brÄck var subjektiv. Retrospektiv klassificering och gradering av brÄckets
omfattning baserat pÄ journalanteckningar Àr mycket begrÀnsad. Viss information var inhÀmtad genom telefonkontakt med djurÀgare som kan minnas fel.
Vetenskaplig eller klinisk relevans: Denna studie visade inget stöd för att kontralateral operation rutinmÀssigt ska rekommenderas efter diagnostisering av ett enkelsidigt perinealbrÄck.Reasons for performing the study: It has been discussed whether perineal hernia in dogs should
possibly be considered a bilateral phenomenon instead of unilateral. However, evidence is limited
regarding the risk of the need of contralateral surgery after unilateral hernia.
Purpose: The hypothesis was that the need for surgery on the contralateral side was rare. The
aim of the study was to investigate the prevalence of contralateral surgery after unilateral procedure
in dogs diagnosed with and treated for unilateral perineal hernia.
Methods: A retrospective cohort study was conducted where a search was made in the medical
record database for dogs subjected to surgery due to perineal hernia covering a period over ten years.
The identified patient records were analysed. The dogs were operated during the years 2009-2018
at the University Animal Hospital in Uppsala, Sweden.
The patients were divided in groups from one to five, where group one consisted of the dogs
with initially single-sided hernia, group two consisted of the initially double-sided dogs, group three
consisted of those dogs with clear hernia on one side and with moderate hernia on the opposite side,
group four consisted of the dogs with clear hernia on one side and a mild hernia on the opposite side
and group five consisted of the dogs that had clear hernia on one side but the opposite side had no
developed hernia but patient record comments about weakened muscles.
In an in-depth analysis, some of the animal owners of dogs in group one was contacted, i.e. the
dogs with only initial unilateral perineal hernia, who had no note of weakness in the muscle wall or
a further hernia on the contralateral side. The pet owners where the information was missing,
whether their dog had had to seek veterinary care due to a contralateral hernia or not, were contacted.
The methods used when contacting the animal owners were telephone calls and text message. Questions that were asked included whether the dog had developed problems with the contralateral side
and whether in that case surgical action had been needed as well as the age of the dog when any
problems arose. If the dog had died, the question was asked whether the dog had died as a result of
perineal hernia or for some other reason.
Results: The study identified a total of 80 male dogs. Group one, initially unilateral hernia consisted of 30 dogs. Group two, initially bilateral hernia was found in 24 dogs. Group three consisted
of two dogs. Group four consisted of five dogs registered with clear hernia on one side and mild
hernia on the opposite side. Group five consisted of 19 dogs that were registered with a clear hernia
on one side and a note that the opposite muscle wall was perceives as flaccid, based on subjective
assessment at rectal palpation. The total number of registered operations was 98, of which were 33
excluding castration and 65 including castration. 15 dogs were bilaterally operated on in two stages,
of which 14 were initially registered as group two, initial as bilateral hernias, and one dog was
registered in group five, loose muscle on the opposite side. The mean age at perineal hernia surgery
was 8.3 years (3.9â14.8 years) and the average weight was 18.2 kg (3.5â49 kg). Development of
contralateral perineal hernia in initially unilateral hernia, group one, was seen in five of 30 dogs.
Two of the five dogs were treated surgically, and one dog was treated conservatively and two were
euthanized due to the contralateral hernia. Of those in group one, initially unilateral hernia, who did
not develop hernia on the contralateral side, two were euthanized during surgery, one dog was euthanized after two months due to recurrence of hernia on the same side and one dog was euthanized
five months after surgery for another cause not related to the perineal hernia. In addition to these
four dogs, the time from surgery to follow-up regarding contralateral hernia in group one, initially
unilateral, was between 11 months â 11.8 years and an average of four years after surgery. The four
dogs that were euthanized in connection with surgery or shortly after surgery were excluded in this
Abstract
study. A total of 19 pet owners were contacted by telephone and/or by text message with standardized questions, of which 15 pet owners answered via telephone calls, two pet owners only via text
message and two pet owners never answered. Through this interview, two of five dogs that developed contralateral hernia were identified. The two dogs whose pet owners failed to be contacted
were chosen to be excluded as well. This resulted in five dogs out of the 24 dogs with initially
unilateral perineal hernia, 20.8 %, developed a contralateral hernia on the opposite side. In those
dogs that had hernias on one side and a comment regarding weakened muscles on the opposite side,
group five, only one dog needed to seek veterinary care and was treated surgically due to having
developed perineal hernias on the opposite side. Of the dogs that were registered as groups 2-5, two
were euthanized in connection with surgery due to a poor prognosis and one shortly after surgery
due to complications that required a new operation. These three dogs were also chosen to be excluded as they were not judged to have the chance of developing a contralateral perineal hernia.
Another two dogs were killed 2.3 years and four years after the operation due to problems with the
hernia operation. Another five dogs were registered as dead due to another cause. A dog with initial
bilateral perineal hernia, group two, was recommended for euthanasia due to tumour disease. 23
dogs, in group 2-5, had no medical record either about if the dogs had been euthanized or if a new
operation had been performed on the non-operated side. This meant that in group 2-5, one dog of 32
(50 dogs minus the 15 dogs that were operated in two steps, minus the three deceased dogs that did
not have a chance to develop problems on the opposite side, when they were euthanized during
surgery or shortly after surgery) needed to seek veterinary care and be treated surgically due to
problems with the opposite side. In summary, out of a total of 56 (24+32) unilaterally treated dogs,
a total of contralateral hernia was seen in six dogs, 10.7 %.
Discussion: Based on the result of this study there is little or no support to give a recommendation that dogs with a unilateral perineal hernia should be subjected to a bilateral surgery. Based on
the results of this study, the recommendation is not to surgically treat a mild perineal hernia on the
contralateral side beyond the side where the main hernia is located. This study indicates that these
hernias usually do not need any form of surgical treatment.
Main study Limitations: The study was retrospective and limited to the patient records from
the University Animal Hospital in Uppsala, Sweden. Some information was obtained through telephone contact with pet owners who could remember incorrectly. Due to the retrospective nature of
the study, the level of evidence regarding grading or scoring of hernia was considered low.
Scientific or Clinical relevance: This study showed no support for contralateral surgery on a
routine basis after diagnosis of unilateral perineal hernia
Lewiston Journal Article, Meat Petition
Newspaper article on meat processing as it pertains to Mailhot\u27s Sausage. (photocopy)https://digitalcommons.usm.maine.edu/michaud-mailhot/1001/thumbnail.jp
The Dream of Coming Home
In the Margaret Chase Smith Essay, Nancy Grape, retired editorial writer for the Portland Press Herald and Maine Sunday Telegram, reflects on the meaning of retirement, and how it is changing in Maine and elsewhere
High Performance Direct Gravitational N-body Simulations on Graphics Processing Units
We present the results of gravitational direct -body simulations using the
commercial graphics processing units (GPU) NVIDIA Quadro FX1400 and GeForce
8800GTX, and compare the results with GRAPE-6Af special purpose hardware. The
force evaluation of the -body problem was implemented in Cg using the GPU
directly to speed-up the calculations. The integration of the equations of
motions were, running on the host computer, implemented in C using the 4th
order predictor-corrector Hermite integrator with block time steps. We find
that for a large number of particles (N \apgt 10^4) modern graphics
processing units offer an attractive low cost alternative to GRAPE special
purpose hardware. A modern GPU continues to give a relatively flat scaling with
the number of particles, comparable to that of the GRAPE. Using the same time
step criterion the total energy of the -body system was conserved better
than to one in on the GPU, which is only about an order of magnitude
worse than obtained with GRAPE. For N\apgt 10^6 the GeForce 8800GTX was about
20 times faster than the host computer. Though still about an order of
magnitude slower than GRAPE, modern GPU's outperform GRAPE in their low cost,
long mean time between failure and the much larger onboard memory; the
GRAPE-6Af holds at most 256k particles whereas the GeForce 8800GTF can hold 9
million particles in memory.Comment: Submitted to New Astronom
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