Research on robot motion control and trajectory tracking based on agricultural seeding

With the development of science and technology, agricultural production has been gradually industrialized, and the use of robots instead of humans for seeding is one of the agricultural industrializations. This paper studied the seeding path planning and path tracking algorithms of the seeding robot, carried out experiments, and compared the improved proportion, integral, differential (PID) algorithm with the traditional PID control algorithm. The results demonstrated that both the improved and non-improved control algorithms played a good role in tracking on the straight path, but the improved control algorithm had a better tracking effect on the turning path; the displacement deviation and angle deviation of the tracking trajectory of the improved PID algorithm were reduced faster and more stable than the traditional PID algorithm; the tracking trajectory was shorter and the operation time of the robot was less under the improved PID algorithm than the traditional one

Characterization of a wheat HSP70 gene and its expression in response to stripe rust infection and abiotic stresses

Members of the family of 70-kD heat shock proteins (HSP70 s) play various stress-protective roles in plants. In this study, a wheat HSP70 gene was isolated from a suppression subtractive hybridization (SSH) cDNA library of wheat leaves infected by Puccinia striiformis f. sp. tritici. The gene, that was designated as TaHSC70, was predicted to encode a protein of 690 amino acids, with a molecular mass of 73.54 KDa and a pI of 5.01. Further analysis revealed the presence of a conserved signature that is characteristic for HSP70s and phylogenetic analysis demonstrated that TaHSC70 is a homolog of chloroplast HSP70s. TaHSC70 mRNA was present in leaves of both green and etiolated wheat seedlings and in stems and roots. The transcript level in roots was approximately threefold less than in leaves but light–dark treatment did not charge TaHSC70 expression. Following heat shock of wheat seedlings at 40°C, TaHSC70 expression increased in leaves of etiolated seedlings but remained stable at the same level in green seedlings. In addition, TaHSC70 was differentially expressed during an incompatible and compatible interaction with wheat-stripe rust, and there was a transient increase in expression upon treatment with methyl jasmonate (MeJA) treatment. Salicylic acid (SA), ethylene (ET) and abscisic acid (ABA) treatments had no influence on TaHSC70 expression. These results suggest that TaHSC70 plays a role in stress-related responses, and in defense responses elicited by infection with stripe rust fungus and does so via a JA-dependent signal transduction pathway

SMA Observations on faint submillimeter galaxies with S 850 < 2 mJy: ultra dusty low-luminosity galaxies at high redshift

We obtained Submillimeter Array (SMA) observations of eight faint (intrinsic 850 μm fluxes < 2 mJy) submillimeter galaxies (SMGs) discovered in SCUBA images of the massive lensing cluster fields A370, A2390, and A1689 and detected five. In total, we obtain five SMA detections, all of which have de-lensed fluxes <1 mJy with estimated total infrared luminosities 1010-1012 L ☉, comparable to luminous infrared galaxies and normal star-forming galaxies. Based on the latest number counts, these galaxies contribute ~70% of the 850 μm extragalactic background light and represent the dominant star-forming galaxy population in the dusty universe. However, only 40$^{+30}_{-16}$% of our faint SMGs would be detected in deep optical or near-infrared surveys, which suggests many of these sources are at high redshifts (z gsim 3) or extremely dusty, and they are not included in current star formation history estimates

Tracing the Mass-Assembly History of Galaxies with Deep Surveys

We use the optical and near-infrared galaxy samples from the Munich Near-Infrared Cluster Survey (MUNICS), the FORS Deep Field (FDF) and GOODS-S to probe the stellar mass assembly history of field galaxies out to z ~ 5. Combining information on the galaxies' stellar mass with their star-formation rate and the age of the stellar population, we can draw important conclusions on the assembly of the most massive galaxies in the universe: These objects contain the oldest stellar populations at all redshifts probed. Furthermore, we show that with increasing redshift the contribution of star-formation to the mass assembly for massive galaxies increases dramatically, reaching the era of their formation at z ~ 2 and beyond. These findings can be interpreted as evidence for an early epoch of star formation in the most massive galaxies in the universe.Comment: 3 pages, 2 figures; published in B. Aschenbach, V. Burwitz, G. Hasinger, B. Leibundgut (eds.): "Relativistic Astrophysics and Cosmology - Einstein's Legacy. Proceedings of the Conference held in Munich, 2006", ESO Astrophysics Symposia, Springer Verlag, 2007, p. 310. Replaced to match final published versio

Properties and Performance of Two Wide Field of View Cherenkov/Fluorescence Telescope Array Prototypes

A wide field of view Cherenkov/fluorescence telescope array is one of the main components of the Large High Altitude Air Shower Observatory project. To serve as Cherenkov and fluorescence detectors, a flexible and mobile design is adopted for easy reconfiguring of the telescope array. Two prototype telescopes have been constructed and successfully run at the site of the ARGO-YBJ experiment in Tibet. The features and performance of the telescopes are presented

Expression of Pseudomonas amyloderamosa isoamylase gene in Saccharomyces cerevisiae

Isoamylase gene (iso) of Pseudomonas amyloderamosa was amplified by polymerase chain reaction and cloned into Saccharomyces cerevisiae vectors under the control of alcohol dehydrogenase gene and glyceraldehyde-3-phosphate dehydrogenase gene promoters. The signal sequence of iso gene was also replaced with that of Schwanniomyces occidentalis alpha-amylase gene. The extracellular isoamylase activity of transformed Sacc. cerevisiae could reach 86 U ml(-1) after a 4-days cultivation