The structural organization and protein composition of lens fiber junctions.

The structural organization and protein composition of lens fiber junctions isolated from adult bovine and calf lenses were studied using combined electron microscopy, immunolocalization with monoclonal and polyclonal anti-MIP and anti-MP70 (two putative gap junction-forming proteins), and freeze-fracture and label-fracture methods. The major intrinsic protein of lens plasma membranes (MIP) was localized in single membranes and in an extensive network of junctions having flat and undulating surface topologies. In wavy junctions, polyclonal and monoclonal anti-MIPs labeled only the cytoplasmic surface of the convex membrane of the junction. Label-fracture experiments demonstrated that the convex membrane contained MIP arranged in tetragonal arrays 6-7 nm in unit cell dimension. The apposing concave membrane of the junction displayed fracture faces without intramembrane particles or pits. Therefore, wavy junctions are asymmetric structures composed of MIP crystals abutted against particle-free membranes. In thin junctions, anti-MIP labeled the cytoplasmic surfaces of both apposing membranes with varying degrees of asymmetry. In thin junctions, MIP was found organized in both small clusters and single membranes. These small clusters also abut against particle-free apposing membranes, probably in a staggered or checkerboard pattern. Thus, the structure of thin and wavy junctions differed only in the extent of crystallization of MIP, a property that can explain why this protein can produce two different antibody-labeling patterns. A conclusion of this study is that wavy and thin junctions do not contain coaxially aligned channels, and, in these junctions, MIP is unlikely to form gap junction-like channels. We suggest MIP may behave as an intercellular adhesion protein which can also act as a volume-regulating channel to collapse the lens extracellular space. Junctions constructed of MP70 have a wider overall thickness (18-20 nm) and are abundant in the cortical regions of the lens. A monoclonal antibody raised against this protein labeled these thicker junctions on the cytoplasmic surfaces of both apposing membranes. Thick junctions also contained isolated clusters of MIP inside the plaques of MP70. The role of thick junctions in lens physiology remains to be determined

Hypertext in the Semantic Web

The Semantic Web extends the current state of the Web with well-defined meaning. We advocate the use of ontological hypertext as an application of the Semantic Web to provide a principled and structured approach to navigating the resources on the Web. This paper demonstrates how we have applied this concept to two real-world scenarios

Hypertext in the Semantic Web

The Semantic Web extends the current state of the Web with well-defined meaning. We advocate the use of ontological hypertext as an application of the Semantic Web to provide a principled and structured approach to navigating the resources on the Web. This paper demonstrates how we have applied this concept to two real-world scenarios

Linking with Meaning: Ontological Hypertext for Scholars

The links in ontological hypermedia are defined according to the relationships between real-world objects. An ontology that models the significant objects in a scholar’s world can be used toward producing a consistently interlinked research literature. Currently the papers that are available online are mainly divided between subject- and publisher-specific archives, with little or no interoperability. This paper addresses the issue of ontological interlinking, presenting two experimental systems whose hypertext links embody ontologies based on the activities of researchers and scholars

The Declining Work Week

Over the past five years average hours per worker, as recorded in the Household Labour Force Survey, have trended downwards. According to the frequently used measure of average hours per worker, total hours divided by total employment, people are now working 5% fewer hours than they were in 2004. This has contributed to weak growth in labour input over recent years. This paper uses data from the Household Labour Force Survey to examine what is behind the recent fall in hours worked per worker. It attempts to answer whether the fall has been due to compositional changes, such as population ageing and increased participation of women, or whether people are just working fewer hours than they used to. This paper estimates that up to 40% of the fall in average hours over the past five years is due to increased annual leave entitlements, while compositional changes are estimated to account for around 11%. The remainder of the fall in average hours appears to be due to a decline in hours worked within jobs. Fewer people working long hours and firms hoarding labour over the recent downturn are identified as two of the key explanations for this

Finding the Balance

Each year the Margaret Chase Smith Library sponsors an essay contest for high school seniors. The essay prompt for 2022 asked students to consider what the proper role of government should be in responding to the current coronavirus pandemic. This is the first-place essay

Underutiilsed Labour: More than the Unemployed?

The official unemployment rate in New Zealand has been below 5%for nearly six years and reached a 22-year low of 3.4% in late 2007. However, official unemployment statistics understate the availability of labour given they do not include an important group of people who want to work - the marginally attached. These are people who want to work, but are either not available or not actively seeking work and therefore are not classified as unemployed. But how different are those people that are marginally attached to the labour force compared to the unemployed? Since 1999, strong employment growth has coincided with a large drop in unemployment but the number of people marginally attached to the labour force has fallen only slightly. Using data from the Household Labour Force Survey, this paper tries to explain the reasons behind this by examining trends in those marginally attached to the labour force and whether this group is significantly different to the officially unemployed. While it is sometimes argued that those marginally attached to the labour force should be combined with the officially unemployed to give a measure of excess supply, this paper investigates whether this is sensible given they appear to be two distinct groups