1,473 research outputs found
The plant-louse Leuronota calycophylli sp. n. (Homoptera, Psylloidea), a pest on the timber species Calycophyllum spruceanum (Rubiaceae) in Peru
An annotated checklist of the psyllids of New Zealand (Hemiptera: Psylloidea)
A checklist of extant species of Psylloidea in New Zealand is presented. The list is structured according to the latest taxonomic classification of families, subfamilies and genera. It includes 99 species, 71 of which are formally described and named, along with information on the host plants and the natural enemies as aspects that are either species-specific or assist in their recognition. An updated distribution of each species is given based on literature records and material held in the major New Zealand entomological collections and databases, including from very recent field surveys. A new record for New Zealand is Phellopsylla formicosa
Psilídeos no Brasil: 8 - Mastigimas anjosi (Hemiptera, Psylloidea), nova praga da Toona ciliata no Brasil.
bitstream/item/82815/1/CT-313-Dalva-final.pd
Mechanical concept of the neurosurgical robot ‘Minerva'
We describe a robot capable of performing all procedures necessary to carry out a complete stereotactic neurosurgical operation under the control and supervision of a surgeon. The operation consists of the introduction of a small probe with diameter 2-3 mm through a hole without trepanation. The robot has been built and is now being tested and evaluated. The accompanying control software as well as various medical probes are either in development or partially tested. The installation will be able to carry out a complete intervention under the surveillance of a computed tomography scanner. In this article we emphasize the design choices required to eliminate gearing backlash in a crucial degree of freedo
Psilídeos do Brasil (Hemiptera, Psylloidea): surpreendente diversidade de um grupo de insetos fitófagos.
Resumo
Robustness against Power is PSPACE-complete
Power is a RISC architecture developed by IBM, Freescale, and several other
companies and implemented in a series of POWER processors. The architecture
features a relaxed memory model providing very weak guarantees with respect to
the ordering and atomicity of memory accesses.
Due to these weaknesses, some programs that are correct under sequential
consistency (SC) show undesirable effects when run under Power. We call these
programs not robust against the Power memory model. Formally, a program is
robust if every computation under Power has the same data and control
dependencies as some SC computation.
Our contribution is a decision procedure for robustness of concurrent
programs against the Power memory model. It is based on three ideas. First, we
reformulate robustness in terms of the acyclicity of a happens-before relation.
Second, we prove that among the computations with cyclic happens-before
relation there is one in a certain normal form. Finally, we reduce the
existence of such a normal-form computation to a language emptiness problem.
Altogether, this yields a PSPACE algorithm for checking robustness against
Power. We complement it by a matching lower bound to show PSPACE-completeness
Treatment of mitral stenosis
In patients with mitral stenosis the need for therapeutic intervention can be assessed by clinical and non-invasive data. Mitral valve replacement is indicated when marked dyspnoea on mild exertion, dyspnoea at rest or pulmonray oedema, haemoptpis, atrial fibrillation, recurrent systemic emboli or right ventricular failure occur in a patient with a mitral valve area of <1·5cm2, as memured by Doppler echocardiography. This treatment will entail life-long anticoagulation in the majoriv of patients. Closed commissurotomy is no longer considered a valid therapeutic alternative due to its limited success rate but open cormmissurotomy and balloon valvotomy may be performed in patients with no significant calcification of valve cusps and no major concomitant mitral regurgitation. Preservation of the subvalvular apparatus and left ventricular geometry can be comidered the most important advantages of these techniques. More severe chronic symptom are generally required m indication for mitral valve replacement because of the additional long-term imponderabilities imposed by an implanted artrficial device. Therefore, in patienb with mitral stenosis different symptom and clinical findings will eventually lead to different intervention
Primeiro registro de Platycorypha nigrivirga Burckhardt (Hemiptera: Psylloidea), em Tipuana tipu (Benth.), no Brasil.
The occurrence of Platycorypha nigrivirga Burckhardt (Hemiptera: Psyllidae, Acizzinae), is reported for the fi rst time, in Brazil. The psyllid was observed causing injuries on leaves and shoots of Tipuana tipu (Benth.), in urban areas of Paraná State. P. nigrivirga are tiny sap-sucking insects that feed on phloem and cause curling, stains and fall of leaves. The excrements of these insects accumulate on the leaves propitiating fungus growth on the leaves, or they fall in great amount on the cars dirtying them as if they were sparkling of white and sticky ink
Linearizability with Ownership Transfer
Linearizability is a commonly accepted notion of correctness for libraries of
concurrent algorithms. Unfortunately, it assumes a complete isolation between a
library and its client, with interactions limited to passing values of a given
data type. This is inappropriate for common programming languages, where
libraries and their clients can communicate via the heap, transferring the
ownership of data structures, and can even run in a shared address space
without any memory protection. In this paper, we present the first definition
of linearizability that lifts this limitation and establish an Abstraction
Theorem: while proving a property of a client of a concurrent library, we can
soundly replace the library by its abstract implementation related to the
original one by our generalisation of linearizability. This allows abstracting
from the details of the library implementation while reasoning about the
client. We also prove that linearizability with ownership transfer can be
derived from the classical one if the library does not access some of data
structures transferred to it by the client
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