Learning what to read: Focused machine reading

Recent efforts in bioinformatics have achieved tremendous progress in the machine reading of biomedical literature, and the assembly of the extracted biochemical interactions into large-scale models such as protein signaling pathways. However, batch machine reading of literature at today's scale (PubMed alone indexes over 1 million papers per year) is unfeasible due to both cost and processing overhead. In this work, we introduce a focused reading approach to guide the machine reading of biomedical literature towards what literature should be read to answer a biomedical query as efficiently as possible. We introduce a family of algorithms for focused reading, including an intuitive, strong baseline, and a second approach which uses a reinforcement learning (RL) framework that learns when to explore (widen the search) or exploit (narrow it). We demonstrate that the RL approach is capable of answering more queries than the baseline, while being more efficient, i.e., reading fewer documents.Comment: 6 pages, 1 figure, 1 algorithm, 2 tables, accepted to EMNLP 201

Observation of the Meissner effect with ultracold atoms in bosonic ladders

We report on the observation of the Meissner effect in bosonic flux ladders of ultracold atoms. Using artificial gauge fields induced by laser-assisted tunneling, we realize arrays of decoupled ladder systems that are exposed to a uniform magnetic field. By suddenly decoupling the ladders and projecting into isolated double wells, we are able to measure the currents on each side of the ladder. For large coupling strengths along the rungs of the ladder, we find a saturated maximum chiral current corresponding to a full screening of the artificial magnetic field. For lower coupling strengths, the chiral current decreases in good agreement with expectations of a vortex lattice phase. Our work marks the first realization of a low-dimensional Meissner effect and, furthermore, it opens the path to exploring interacting particles in low dimensions exposed to a uniform magnetic field

Bilayered constructs aimed at osteochondral strategies : the influence of media supplements in the osteogenic and chondrogenic differentiation of amniotic fluid-derived stem cells

injuries and aging associated diseases that affect joints. This study reports the development of a bilayered scaffold, which consists of both bone and cartilage regions. On the other hand, amniotic fluid-derived stem cells (AFSCs) could be differentiated into either osteogenic or chondrogenic cells, respectively. In this study we have developed a bilayered scaffolding system, which includes a starch/polycaprolactone (SPCL) scaffold for osteogenesis and an agarose hydrogel for chondrogenesis. AFSC-seeded scaffolds were cultured for 1 or 2 weeks in an osteochondral-defined culture medium containing both osteogenic and chondrogenic differentiation factors. Additionally, the effect of the presence or absence of insulin-like growth factor-1 (IGF-1) in the culture medium was assessed. Cell viability and phenotypic expression were assessed within the constructs in order to determine the influence of the osteochondral differentiation medium. The results indicated that, after osteogenic differentiation, AFSCs that had been seeded onto SPCL scaffolds did not require osteochondral medium to maintain their phenotype, and they produced a protein-rich, mineralized extracellular matrix (ECM) for up to 2 weeks. However, AFSCs differentiated into chondrocyte-like cells appeared to require osteochondral medium, but not IGF-1, to synthesize ECM proteins and maintain the chondrogenic phenotype. Thus, although IGF-1 was not essential for creating osteochondral constructs with AFSCs in this study, the osteochondral supplements used appear to be important to generate cartilage in long-term tissue engineering approaches for osteochondral interfaces. In addition, constructs generated from agarose–SPCL bilayered scaffolds containing pre-differentiated AFSCs may be useful for potential applications in regeneration strategies for damaged or diseased joints.Fundação para a Ciência e a Tecnologia (FCT

Direct measurement of the Zak phase in topological Bloch bands

Geometric phases that characterize the topological properties of Bloch bands play a fundamental role in the band theory of solids. Here we report on the measurement of the geometric phase acquired by cold atoms moving in one-dimensional optical lattices. Using a combination of Bloch oscillations and Ramsey interferometry, we extract the Zak phase—the Berry phase gained during the adiabatic motion of a particle across the Brillouin zone—which can be viewed as an invariant characterizing the topological properties of the band. For a dimerized lattice, which models polyacetylene, we measure a difference of the Zak phase δφZak = 0.97(2)π for the two possible polyacetylene phases with different dimerization. The two dimerized phases therefore belong to different topological classes, such that for a filled band, domain walls have fractional quantum numbers. Our work establishes a new general approach for probing the topological structure of Bloch bands inoptical lattices

Tenogenic potential of human stem cells from the amniotic fluid and adipose tissue

Tendons are highly prone to injury and the intrinsic hypocellularity and hypovascularity make their natural healing extremely slow and inefficient when severed damaged. Surgical repair with grafts is common but unsuccessful in a long term basis. The development of tissue engineering strategies based on stem cells explores a natural endogenous system of regeneration with potential for tendon application. We propose to establish biochemical culturing conditions to assess the tenogenic potential of human adipose stem cells (hASCs) and amniotic fluid-derived stem cells (hAFSCs), known for their proliferative and differentiation capacities. Since several growth factors (GFs) participate in tendon formation and ECM synthesis, these GFs were added to the culture medium to stimulate tenogenic differentiation of these cells. This study also envisions the application of hASCs and/or hAFSCs in cell-based strategies for tendon repair

Use of Information and Communication Technologies among Extension Agents In Kano State, Nigeria

The study assessed the use of ICTs among extension agents in Kano State Nigeria. Two hundred and twenty-one (221) extension agents were randomly selected from the 44 local government areas. Data for the study were obtained with the aid of structured questionnaire administered to extension agents. Majority of extension agents were in the age range of 41-50 years. Majority (87.3%) of them were males and married (100%), with family sizes of 5-14 (53.95%). The entire extension agents had formal education including HND (35.8%), OND (33.3%) and secondary school certificate (27.2%). Most of the extension agents had an annual income of N100,000- N300,000, with N376,984 as mean. They were aware and had access to radio, television, telephone, DVD, video, camera, computer, satellite and printer. They however recorded a low usage of the Web, satellite, e-mail, CD-ROM, search engines, scanner, fax and Web publishing. The result also indicates a positive correlation between ICT use and socio-economic characteristics of the agents; including age, work experience, membership of agricultural associations (p<0.05). It was concluded that the benefits of the ICTs were not fully utilized by extension workers in the state due to some factors associated with low income, ICTs training, awareness and access

Use of Information and Communication Technologies among Extension Agents In Kano State, Nigeria

The study assessed the use of ICTs among extension agents in Kano State Nigeria. Two hundred and twenty-one (221) extension agents were randomly selected from the 44 local government areas. Data for the study were obtained with the aid of structured questionnaire administered to extension agents. Majority of extension agents were in the age range of 41-50 years. Majority (87.3%) of them were males and married (100%), with family sizes of 5-14 (53.95%). The entire extension agents had formal education including HND (35.8%), OND (33.3%) and secondary school certificate (27.2%). Most of the extension agents had an annual income of N100,000- N300,000, with N376,984 as mean. They were aware and had access to radio, television, telephone, DVD, video, camera, computer, satellite and printer. They however recorded a low usage of the Web, satellite, e-mail, CD-ROM, search engines, scanner, fax and Web publishing. The result also indicates a positive correlation between ICT use and socio-economic characteristics of the agents; including age, work experience, membership of agricultural associations (p<0.05). It was concluded that the benefits of the ICTs were not fully utilized by extension workers in the state due to some factors associated with low income, ICTs training, awareness and access