PDDL2.1: An Extension to PDDL for Expressing Temporal Planning Domains

In recent years research in the planning community has moved increasingly toward s application of planners to realistic problems involving both time and many typ es of resources. For example, interest in planning demonstrated by the space res earch community has inspired work in observation scheduling, planetary rover ex ploration and spacecraft control domains. Other temporal and resource-intensive domains including logistics planning, plant control and manufacturing have also helped to focus the community on the modelling and reasoning issues that must be confronted to make planning technology meet the challenges of application. The International Planning Competitions have acted as an important motivating fo rce behind the progress that has been made in planning since 1998. The third com petition (held in 2002) set the planning community the challenge of handling tim e and numeric resources. This necessitated the development of a modelling langua ge capable of expressing temporal and numeric properties of planning domains. In this paper we describe the language, PDDL2.1, that was used in the competition. We describe the syntax of the language, its formal semantics and the validation of concurrent plans. We observe that PDDL2.1 has considerable modelling power --- exceeding the capabilities of current planning technology --- and presents a number of important challenges to the research community.

The 3rd International Planning Competition: Results and Analysis

This paper reports the outcome of the third in the series of biennial international planning competitions, held in association with the International Conference on AI Planning and Scheduling (AIPS) in 2002. In addition to describing the domains, the planners and the objectives of the competition, the paper includes analysis of the results. The results are analysed from several perspectives, in order to address the questions of comparative performance between planners, comparative difficulty of domains, the degree of agreement between planners about the relative difficulty of individual problem instances and the question of how well planners scale relative to one another over increasingly difficult problems. The paper addresses these questions through statistical analysis of the raw results of the competition, in order to determine which results can be considered to be adequately supported by the data. The paper concludes with a discussion of some challenges for the future of the competition series.

Dexamphetamine treatment in stroke

Reducing disability and dependency after a stroke is an important clinical objective. We examine what is known about the use of dexamphetamine in patients recovering from an acute stroke, and consider whether further clinical studies should be undertaken. Dexamphetamine has repeatedly been shown to enhance recovery after experimental brain injury in animals, the best effects being seen when dexamphetamine is combined with lesion-specific motor training or sensory stimulation. Postulated mechanisms for these beneficial effects in animals are in keeping with contemporary theories of neurophysiological rehabilitation in man. There have been few clinical studies of dexamphetamine during rehabilitation after an acute stroke. Four controlled trials demonstrated a tendency to an improved outcome when dexamphetamine was paired with therapy and administered 3-30 days after an ischaemic stroke. However, clinical studies to date have been small, included only highly selected patients, and have not addressed possible confounding effects of the drug on mood and untreated depression. Dexamphetamine has previously been used under supervision in medically ill patients and appears to be safe and well-tolerated. There is a need for well-designed studies to assess further the safety and efficacy of dexamphetamine in rehabilitation after stroke.

The crossover from 2D to 3D percolation: theory and numerical simulations

We describe here the crossover between 2D and 3D percolation, which we do on cubic and square lattices. As in all problems of critical phenomena, the quantities of interest can be expressed as power laws of /p-pc(h)/, where pc(h) and h are the percolation threshold and the thickness of the film, respectively. When these quantities are considered on the scale of the thickness h of the films, the corresponding numerical prefactors are of order one. However, for many problems, the scale of interest is the elementary one. The corresponding expressions contain then prefactors in power of h which we calculate. For instance, we show that the mass distribution n(m) of the clusters is given by a master function of h(-D+1/sigma2nu3)/p-pc(h)/1/sigma2(m), where h is the thickness of the film and D, nu3, sigma2 are tabulated 2D and 3D critical exponents. We consider also the size R2( m) of the clusters as a function of their mass m, for which we provide both scaling laws and numerical data. Therefore, any property corresponding to a given moment of mass and size can be obtained from our results. These results might be useful for describing transport properties, such as electric conductivity, or the mechanical properties of thin films made of disordered materials.

The cold-water coral Lophelia pertusa (Scleractinia) and enigmatic seabed mounds along the north-east Atlantic margin: are they related?

In this study, an updated distribution of Lophelia pertusa between the Porcupine Seabight and Norwegian shelf is presented. It seems unlikely that enigmatic mound structures observed at water depths of more than 570 m during acoustic seabed surveys, particularly to the west of the Shetland Islands, are related to the occurrence of L. pertusa. At these depths in the Faroe-Shetland Channel, the predominant influence of cold Arctic water precludes its growth. Iceberg dumpsites are also considered unlikely explanations for the origin of these mounds, and they are interpreted as most likely to be related to the release of fluids at the seabed. When mound structures were investigated, no scleractinian corals were recovered at water depths >500 m. This study shows the importance of seabed temperature as an environmental control on cold-water coral distribution. The significance of cold-water coral habitats in sustaining high levels of local-scale biodiversity is now becoming apparent in parallel with increased hydrocarbon extraction and fishing activity beyond the shelf edge. There is growing evidence that these areas have been marked by the passage of deep-water trawls. It seems likely that trawling activity has already reduced the extent of cold-water coral distribution in this region of the north-east Atlantic.

Heterogeneous dynamics at the glass transition in van der Waals liquids: determination of the characteristic scale

Recent experiments have demonstrated that the dynamics in liquids close to the glass transition temperature is strongly heterogeneous. The characteristic size of these heterogeneities has been measured to be a few nanometers at Tg. We extend here a recent model for describing the heterogeneous nature of the dynamics which allows both to derive this length scale and the right orders of magnitude of the heterogeneities of the dynamics close to the glass transition. Our model allows then to interpret quantitatively small probes diffusion experiments.

Possible roles for corticosterone and critical size in the fledging of nestling pied flycatchers

Our study was designed to see whether corticosterone (B) rises abruptly in the blood of nestling pied flycatchers (Ficedula hypoleuca) at the time they fledge, as reported recently for kestrels, and if so, why. We measured the growth and blood levels of B and selected nutrients of nestlings in broods of five, seven, and nine chicks during 1998 and 1999. In half of the broods, we clipped selected wing and tail feathers of both parents with the intention of making it more difficult for them to provide their chicks with food. We collected blood samples when the chicks were six to 10 d old (period of rapid growth) and 15 d of age or older (0-5 d before fledging). B increased substantially several days before the chicks left the nest and then declined somewhat. We found no differences in rates of growth or blood levels of B, nutrients, and hematocrit as a function of either brood size or parental handicapping. Nestlings within a day of fledging appear to have been food deprived in 1998; their glucose was significantly reduced, and B, free fatty acids, and glycerol were significantly elevated compared to levels in chicks 1-4 d younger. Such changes did not occur in 1999. Blood levels of B were significantly correlated with brood size near the day of fledging, but not earlier, in both years of the study. It was possible to predict the day on which chicks would leave the nest, using their wing length when 12 d old. These results suggest that high blood levels of B associated with food restriction and sibling competition induce chicks to fledge, provided they have reached a critical size, and that the importance of fasting, sibling competition, and B may vary from year to year.

ACAULIS5, an Arabidopsis gene required for stem elongation, encodes a spermine synthase

Polyamines have been implicated in a wide range of biological processes, including growth and development in bacteria and animals, but their function in higher plants is unclear. Here we show that the Arabidopsis: ACAULIS5 (ACL5) gene, whose inactivation causes a defect in the elongation of stem internodes by reducing cell expansion, encodes a protein that shares sequence similarity with the polyamine biosynthetic enzymes spermidine synthase and spermine synthase. Expression of the recombinant ACL5 protein in Escherichia coli showed that ACL5 possesses spermine synthase activity. Restoration of the acl5 mutant phenotype by somatic reversion of a transposon-induced allele suggests a non-cell-autonomous function for the ACL5 gene product. We also found that expression of the ACL5 cDNA under the control of a heat shock gene promoter in acl5 mutant plants restores the phenotype in a heat shock-dependent manner. The results of the experiments showed that polyamines play an essential role in promotion of internode elongation through cell expansion in Arabidopsis: We discuss the relationships to plant growth regulators such as auxin and gibberellins that have related functions.

[Determination of scalp ER and AR of patients with male pattern baldness and the effects of hair transplantation on them]

OBJECTIVE

To study the role of sex hormone receptor capacity of the scalp in male pattern baldness(MPB).

METHODS

Estrogen receptor(ER) and androgen receptor(AR) assays were performed using fluorescent steroid hormone conjugate technique (FSHCT) in hairness and bald scalp in 8 patients with MPB. Changes of ER and AR capacity in recipient and donor sites of hair transplantation in MPB scalps were examined.

RESULTS

The percentage of AR staining cells in the outer root sheath, sebaceous gland and bulb papilla of the lesional scalps was significantly higher than that of hairness scalps (P < 0.01). The percentage of ER positive cells in the outer root sheath of lesional scalps increased significantly (P < 0.01).

CONCLUSION

Changes of contents of sex hormone receptors(SHR) in some sensitive area of the scalp induce MPB.

Changes in a murine leukemia virus (MLV) receptor encoded by an alphavirus vector during passage in cells expressing the MLV envelope

We constructed alphavirus vectors encoding the ecotropic murine leukemia virus (MLV) receptor mCAT1. Cells electroporated with these vector RNAs expressed mCAT1 protein and fused with cells that expressed a fusogenic form of the MLV envelope on the cell surface. Electroporated cells also released submicron particles that were infectious in envelope-expressing cells. Infection resulted in giant syncytia that could be enumerated by plaque assay. Cell-free supernatants could be serially passaged and contained up to 10(4) infectious units/ml. To determine whether repeated passage would select for functional variants of the receptor, we analyzed mCAT1 amplified by RT-PCR after 12 serial passages. Several amino acid substitutions were identified that encoded functional receptor variants. In independent experiments, variants containing an isoleucine or a leucine instead of a phenylalanine at position 224 in the third extracellular domain of the receptor arose spontaneously and outgrew the parental vector, indicating that mutations at this site are highly selected in this system. This region of the receptor has previously been implicated in the envelope-receptor interaction. This alphavirus vector system provides a novel method for generating and selecting functional variants of viral receptors

[The value of anesthesia consultation in relation to the single preanesthetic visit]

OBJECTIVE

In France, a preanaesthetic assessment (PAA) several days prior to hospital admission for a scheduled surgical or diagnostic procedure under anaesthesia, associated with a preanaesthetic visit (PAV) the day before, are compulsory. This study aimed at comparing the benefits of PAA with those of a PAV not preceded by a PAA.

STUDY DESIGN

Prospective, controlled, randomized study.

PATIENTS

The study included 296 patients undergoing either a urologic, or ophthalmologic, or ENT procedure, randomly allocated either to a PAA (followed by a PAV) group or a PAV (without previous PAA) group.

METHODS

The main criterion of comparison was the duration of preanaesthetic hospital stay and the secondary criteria were the incidence of procedure postponements and patients' satisfaction respectively.

RESULTS

In the PAA group, the preanaesthetic hospital stay was shorter by 0.4 days (P = 0.001). Out of the 19 postponed procedures (7%), the cause of postponement was a medical one in 15 patients: 13 in the PAV group and 2 in the PAA group respectively (P = 0.009). The PAA was not considered as a constraint by most patients.

CONCLUSION

The PAA shortens the duration of preanaesthetic hospital stay and decreases the incidence of procedures postponed for a medical cause.

The heat moisture exchange device (HME) in neonatal ventilation

The objective of this study was to compare the safety and efficacy of the Heat Moisture Exchange (HME) device with conventional humidification in neonates. Sixty-four neonates were randomized at intubation to receive conventional humidification (CH) (n = 34) or HME, via a Neoaid device (n = 30). Groups were compared for intrinsic characteristics and outcome variables. Data were assumed nonparametric and analyzed by Mann-Whitney and Fisher's Exact test. No significant differences were found in group characteristics or outcome variables. Trends were noted for documented patent ductus arteriosus (PDA), endotracheal tube blockage, and positive endotracheal aspirate culture. Rate of pneumothorax 2/34 (CH) versus 4/30 (HME) (p = 0.4); rate of tube blockage 3/34 (CH) versus 2/30 (HME) (p = 1.0); rate of PDA 8/34 (CH) versus 14/30 (HME) (p = 0.093) and rate of endotracheal colonisation 1 7/34 (CH) versus 9/30 (HME) (p = 0.17). No significant difference was found for duration of ventilation or period in greater than 40% oxygen between the two groups. There were no significant outcome differences between CH and HME. The HME device was cost-effective and simple to use. A larger multicenter trial is warranted to confirm the efficacy of HME.

Electroosmotic Flows Created by Surface Defects in Capillary Electrophoresis

We compute the electroosmotic flow in nonuniformly charged planar and cylindrical capillaries for the limit of low-Reynolds-number flows and thin Debye layers. Analytical formulae for the velocity field are provided for the general case of an arbitrary surface inhomogeneity but we also focus on various specific defect geometries. Many important features can be obtained from the simple lubrication approximation. The pressure jump induced by the presence of such surface defects is calculated and the possible occurrence of recirculating flows is discussed, as are effects of the flow perturbations on dispersion in capillary electrophoresis. Copyright 1999 Academic Press.

Chemotherapy-induced inflammation in seborrheic keratoses mimicking disseminated herpes zoster

We report a rare instance of chemotherapy-induced seborrheic keratoses of Leser-Trelat in a patient with acute leukemia. In addition, this is the first known case to mimic disseminated herpes zoster.

Efficient Implementation of the Plan Graph in STAN

STAN is a Graphplan-based planner, so-called because it uses a variety of STate ANalysis techniques to enhance its performance. STAN competed in the AIPS-98 planning competition where it compared well with the other competitors in terms of speed, finding solutions fastest to many of the problems posed. Although the domain analysis techniques STAN exploits are an important factor in its overall performance, we believe that the speed at which STAN solved the competition problems is largely due to the implementation of its plan graph. The implementation is based on two insights: that many of the graph construction operations can be implemented as bit-level logical operations on bit vectors, and that the graph should not be explicitly constructed beyond the fix point. This paper describes the implementation of STAN's plan graph and provides experimental results which demonstrate the circumstances under which advantages can be obtained from using this implementation.

Sweet's syndrome and erythema nodosum: the simultaneous occurrence of 2 reactive dermatoses

BACKGROUND

The simultaneous occurrence of Sweet's syndrome (SS) and erythema nodosum (EN) in 1 patient is rare. Our review of the literature revealed only 11 biopsy-proved cases in which the 2 reactive dermatoses occurred together. None were associated with an underlying malignant neoplasm.

OBSERVATIONS

We report a biopsy-proved case of SS and EN occurring simultaneously in a patient with an underlying malignant neoplasm (specifically, acute myelogenous leukemia). We also report another biopsy-proved case of SS and EN occurring simultaneously in a patient with underlying Crohn's disease.

CONCLUSIONS

The simultaneous occurrence of SS and EN in 1 patient is rarely reported. Both disorders are reactive dermatoses that share many overlapping features. Although individually distinctive, SS and EN are also part of a growing continuum of reactive dermatoses. Our expanded understanding of the similarities and simultaneous manifestation of SS and EN may help us in the future to identify a common underlying mechanism of pathogenesis.

[Prevention and treatment of eyelid retraction and ectropion following lower eyelid blepharoplasty with tarsal tuck procedure]

OBJECTIVE

To prevent or decrease eyelid retraction and ectropion following lower eyelid blepharoplasty.

METHODS

The tarsal tuck procedure was performed during lower eyelid blepharoplasty to tighten the lower eyelid. This method had been used since 1991.

RESULTS

After the operation, the lower eyelid was tensional and steady. The complications of eyelid retraction and ectropion were diminished.

CONCLUSION

The pathologic basis of the eyelid bag is that the supporting tissues become lax so that the lower eyelid and lateral canthus move downwards. The exact aim of the tarsal tuck procedure is to correct these pathologic changes.

The Automatic Inference of State Invariants in TIM

As planning is applied to larger and richer domains the effort involved in constructing domain descriptions increases and becomes a significant burden on the human application designer. If general planners are to be applied successfully to large and complex domains it is necessary to provide the domain designer with some assistance in building correctly encoded domains. One way of doing this is to provide domain-independent techniques for extracting, from a domain description, knowledge that is implicit in that description and that can assist domain designers in debugging domain descriptions. This knowledge can also be exploited to improve the performance of planners: several researchers have explored the potential of state invariants in speeding up the performance of domain-independent planners. In this paper we describe a process by which state invariants can be extracted from the automatically inferred type structure of a domain. These techniques are being developed for exploitation by STAN, a Graphplan based planner that employs state analysis techniques to enhance its performance.

Abuse against women in rural Minnesota

The purpose of this study was to examine the prevalence of physical, emotional, and sexual abuse in women seeking care in rural medical clinics and WIC supplemental food program sites, as well as to examine demographic and health characteristics related to abuse. This was a descriptive, cross-sectional study using a self-administered, anonymous survey. Data were collected in 8 medical clinics and 17 WIC supplemental food program sites in 9 counties of west-central Minnesota during January and February, 1997. The survey instrument asked brief screening questions on physical, emotional, and sexual abuse as well as demographic and health related questions designed to reflect the rural population and characteristics. The survey results showed that in the prior 12 months, 109 (6.6%) of the respondents reported physical abuse, 347 (21.1%) reported emotional/verbal abuse, and 35 (2.1%) reported sexual abuse. Proportional increases in risk of current abuse relative to married women were 2.1 for single, 2.5 for divorced, and 6.5 for separated women, after adjusting for other important variables. Single women with a recent status change had significantly higher risk of current abuse than women with a recent status change at all other marital status levels in adjusted analyses. Women who reported some form of abuse before age 18, and women reporting abuse as an adult prior to the last 12 months, were significantly more likely to report current abuse in all analyses. Prior abuse as an adult was the single best predictor of current abuse in a final logistic regression model.