PALMER: Perception-Action Loop with Memory for Long-Horizon Planning

To achieve autonomy in a priori unknown real-world scenarios, agents should be able to: i) act from high-dimensional sensory observations (e.g., images), ii) learn from past experience to adapt and improve, and iii) be capable of long horizon planning. Classical planning algorithms (e.g. PRM, RRT) are proficient at handling long-horizon planning. Deep learning based methods in turn can provide the necessary representations to address the others, by modeling statistical contingencies between observations. In this direction, we introduce a general-purpose planning algorithm called PALMER that combines classical sampling-based planning algorithms with learning-based perceptual representations. For training these perceptual representations, we combine Q-learning with contrastive representation learning to create a latent space where the distance between the embeddings of two states captures how easily an optimal policy can traverse between them. For planning with these perceptual representations, we re-purpose classical sampling-based planning algorithms to retrieve previously observed trajectory segments from a replay buffer and restitch them into approximately optimal paths that connect any given pair of start and goal states. This creates a tight feedback loop between representation learning, memory, reinforcement learning, and sampling-based planning. The end result is an experiential framework for long-horizon planning that is significantly more robust and sample efficient compared to existing methods.Comment: Website: https://palmer.epfl.c

Yield quantitative trait loci from wild tomato are predominately expressed by the shoot

Plant yield is the integrated outcome of processes taking place above and below ground. To explore genetic, environmental and developmental aspects of fruit yield in tomato, we phenotyped an introgression line (IL) population derived from a cross between the cultivated tomato (Solanum lycopersicum) and a wild species (Solanum pennellii). Both homozygous and heterozygous ILs were grown in irrigated and non-irrigated fields and evaluated for six yield components. Thirteen lines displayed transgressive segregation that increased agronomic yield consistently over 2 years and defined at least 11 independent yield-improving QTL. To determine if these QTL were expressed in the shoots or the roots of the plants, we conducted field trials of reciprocally grafted ILs; out of 13 lines with an effect on yield, 10 QTL were active in the shoot and only IL8-3 showed a consistent root effect. To further examine this unusual case, we evaluated the metabolic profiles of fruits from both the homo- and heterozygous lines for IL8-3 and compared these to those obtained from the fruit of their equivalent genotypes in the root effect population. We observed that several of these metabolic QTL, like the yield QTL, were root determined; however, further studies will be required to delineate the exact mechanism mediating this effect in this specific line. The results presented here suggest that genetic variation for root traits, in comparison to that present in the shoot, represents only a minor component in the determination of tomato fruit yield. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00122-010-1456-9) contains supplementary material, which is available to authorized users

Yield quantitative trait loci from wild tomato are predominately expressed by the shoot

Plant yield is the integrated outcome of processes taking place above and below ground. To explore genetic, environmental and developmental aspects of fruit yield in tomato, we phenotyped an introgression line (IL) population derived from a cross between the cultivated tomato (Solanum lycopersicum) and a wild species (Solanum pennellii). Both homozygous and heterozygous ILs were grown in irrigated and non-irrigated fields and evaluated for six yield components. Thirteen lines displayed transgressive segregation that increased agronomic yield consistently over 2 years and defined at least 11 independent yield-improving QTL. To determine if these QTL were expressed in the shoots or the roots of the plants, we conducted field trials of reciprocally grafted ILs; out of 13 lines with an effect on yield, 10 QTL were active in the shoot and only IL8-3 showed a consistent root effect. To further examine this unusual case, we evaluated the metabolic profiles of fruits from both the homo- and heterozygous lines for IL8-3 and compared these to those obtained from the fruit of their equivalent genotypes in the root effect population. We observed that several of these metabolic QTL, like the yield QTL, were root determined; however, further studies will be required to delineate the exact mechanism mediating this effect in this specific line. The results presented here suggest that genetic variation for root traits, in comparison to that present in the shoot, represents only a minor component in the determination of tomato fruit yield

Participation in Daily Activities and Quality of Life among Individuals with Paraplegic Spinal Cord Injury in Pakistan

Individuals with paraplegic Spinal Cord Injury (SCI) face various difficulties that limit participation in daily activities and lowered Quality of Life (QOL) after hospital discharge. This cross-sectional study aimed to investigate the level of participation in daily activities and QOL among individuals with paraplegic SCI and to examine the relationship between these two variables. The results revealed that individuals with paraplegic SCI faced significant challenges in social participation, life activities, mobility, getting along, self-care, and cognition, leading to a reduction in overall QOL. Occupational therapists prioritize post-discharge interventions targeting to improve participation and QOL for successful rehabilitation and community reintegration

Part I. The structure of lyconnotine. Part II. Studies of some derivatives of cyclohexane. Part III. Studies of some derivatives of bicyclo[2.2.1]heptane.

Part I. Lyconnotine, an alkaloid of Lycopodium annotinum L. has been isolated by an improved method. Isolation of a derivative of lyconnotine has also been accomplished. The structure and stereochemistry of these alkaloids have been established on the basis of chemical and spectral evidence. Attempts to interrelate acrifoline and dihydro-acrifoline to lyconnotine by photochemical cleavage of the former two alkaloids have been unsuccessful. On photolysis, a complicated mixture of a number of components is obtained. It has been shown that the major photoproducts cannot be readily converted to lyconnotine. Part II. The preparation of (i) cyclohexane- cis-3,3,4,5,6,6-d6, (ii) cis-1,2-dicarbomethoxy cyclohexane-cis-3,3,4,5,6,6-d6, and (iii) cyclohexane-3,3,6,6-d 4 has been achieved. The N.M.R. spectra of these compounds at ambient and lower temperatures are discussed and various kinetic parameters for conformational changes in cyclohexene have been obtained. Values of the coupling constants in cyclohexane are furnished. Part III. The syntheses of a number of 7-substituted bicyclo[2.2.1]heptane derivatives are described. Representative compounds include 7-isopropylidene bicyclo[2.2.1]hept-5-ene-exo-2,3-diol carbonate Ia, the corresponding endo isomer Ib, exo-2,3-dihydroxy-7-isopropylidene bicyclo[2.2.1]hept-5-ene IIa, the corresponding endo diol IIb, 7-isopropylidene bicyclo[2.2.1]hept-5-ene- exo-2,3-diol thionocarbonate, IIIa and its endo counterpart IIIb. Products of catalytic reduction of compounds Ia, IIa and IIIa have also been obtained. Configurations of these compounds have been established on the basis of their N.M.R. spectra. Attempts to obtain 7-isopropylidene bicyclo[2.2.1]hepta-2,5-diene have been unsuccessful. The anisotropic effect of the double bond in the above series and in the 7,7-dimethylene bicyclo[2.2.1]heptane derivatives is discussed and compared with the previous results in the literature

Part I. The structure of lyconnotine. Part II. Studies of some derivatives of cyclohexane. Part III. Studies of some derivatives of bicyclo[2.2.1]heptane.

Part I. Lyconnotine, an alkaloid of Lycopodium annotinum L. has been isolated by an improved method. Isolation of a derivative of lyconnotine has also been accomplished. The structure and stereochemistry of these alkaloids have been established on the basis of chemical and spectral evidence. Attempts to interrelate acrifoline and dihydro-acrifoline to lyconnotine by photochemical cleavage of the former two alkaloids have been unsuccessful. On photolysis, a complicated mixture of a number of components is obtained. It has been shown that the major photoproducts cannot be readily converted to lyconnotine. Part II. The preparation of (i) cyclohexane- cis-3,3,4,5,6,6-d6, (ii) cis-1,2-dicarbomethoxy cyclohexane-cis-3,3,4,5,6,6-d6, and (iii) cyclohexane-3,3,6,6-d 4 has been achieved. The N.M.R. spectra of these compounds at ambient and lower temperatures are discussed and various kinetic parameters for conformational changes in cyclohexene have been obtained. Values of the coupling constants in cyclohexane are furnished. Part III. The syntheses of a number of 7-substituted bicyclo[2.2.1]heptane derivatives are described. Representative compounds include 7-isopropylidene bicyclo[2.2.1]hept-5-ene-exo-2,3-diol carbonate Ia, the corresponding endo isomer Ib, exo-2,3-dihydroxy-7-isopropylidene bicyclo[2.2.1]hept-5-ene IIa, the corresponding endo diol IIb, 7-isopropylidene bicyclo[2.2.1]hept-5-ene- exo-2,3-diol thionocarbonate, IIIa and its endo counterpart IIIb. Products of catalytic reduction of compounds Ia, IIa and IIIa have also been obtained. Configurations of these compounds have been established on the basis of their N.M.R. spectra. Attempts to obtain 7-isopropylidene bicyclo[2.2.1]hepta-2,5-diene have been unsuccessful. The anisotropic effect of the double bond in the above series and in the 7,7-dimethylene bicyclo[2.2.1]heptane derivatives is discussed and compared with the previous results in the literature