A special case of the Buchsbaum-Eisenbud-Horrocks rank conjecture

The Buchsbaum-Eisenbud-Horrocks rank conjecture proposes lower bounds for the Betti numbers of a graded module M based on the codimension of M. We prove a special case of this conjecture via Boij-Soederberg theory. More specifically, we show that the conjecture holds for graded modules where the regularity of M is small relative to the minimal degree of a first syzygy of M. Our approach also yields an asymptotic lower bound for the Betti numbers of powers of an ideal generated in a single degree.Comment: 11 pages, 1 figur

Swimming of onboard-powered autonomous robots in viscous fluid filled channels

Microrobots can make a great impact in medical applications such as minimally-invasive surgery, screening and diagnosis of diseases, targeted therapy and drug delivery. Smallsized bio-inspired robots can mimic flagellar propulsion mechanisms of microorganisms for actuation in microfluidic environments, which are dominated by viscous forces. Microorganisms propel themselves by means of the motion of their flagella such as rotation of rigid helices or travelling planar waves on flexible tails similar to whipping motion. Here, we present characterization of swimming of onboard-powered autonomous robots inside cylindrical tubes. Robots consist of two links, head and tail, connected with a revolute joint. Rigid helical tails of the swimmer robots are made of steel wires with 12 different configurations of helical radius and pitch. From experiments forward linear velocity of robots and angular velocities of the links are measured, and compared with the mathematical model, which is based on the resistive force theory. Results indicate that the motion of the swimmer inside channels can be predicted by means of the resistive force theory reasonably well

Chinese Taukeh, Labourer, and State Control Case Study of Panglong in Eastern Region of Sumatra (1890-1930)

Recently the flow of labour from China to Indonesia has fuelled many discussions but is not a new phenomenon. It can be traced back to the eighteenth century and continued until the twentieth century. In colonial Indonesia, the Chinese labour force was recruited to work in the economic sectors of mining, plantations, fisheries and forestry. Unfortunately, previous studies about Chinese society in Indonesia more focused on economic and political elites rather than the social history of the Chinese contract coolies. This article attempts to look at the labour history of the Chinese coolie in the forest exploitation companies, known as panglong. By focusing on the ways in which they were treated in the recruitment process and workplace, this article shows that changes for the better did take place in the appalling working conditions of the labourers. Until the second decade of the twentieth century, recruitment, food, and health care were rife with manipulations, exacerbated by arduous working conditions and insecurity in the workplace, abuse of power by mandors and forms of non-economic coercion like the use of opium. All these factors were meant to ensure that the Chinese contract labourers could not break loose from their indentures, a modern form of slavery. Hampered by budgetary restrictions, lack of personnel, and marine transport facilities, the state colonial officials were hamstrung. But in the second decade of twentieth century, when the abysmal working conditions of the Chinese coolies were debated on a higher level by politicians and bureauracts state control was tightened. More effectual control by the state had a positive effect on improving of the working and living conditions