Impact of URI Canonicalization on Memento Count

Quantifying the captures of a URI over time is useful for researchers to identify the extent to which a Web page has been archived. Memento TimeMaps provide a format to list mementos (URI-Ms) for captures along with brief metadata, like Memento-Datetime, for each URI-M. However, when some URI-Ms are dereferenced, they simply provide a redirect to a different URI-M (instead of a unique representation at the datetime), often also present in the TimeMap. This infers that confidently obtaining an accurate count quantifying the number of non-forwarding captures for a URI-R is not possible using a TimeMap alone and that the magnitude of a TimeMap is not equivalent to the number of representations it identifies. In this work we discuss this particular phenomena in depth. We also perform a breakdown of the dynamics of counting mementos for a particular URI-R (google.com) and quantify the prevalence of the various canonicalization patterns that exacerbate attempts at counting using only a TimeMap. For google.com we found that 84.9% of the URI-Ms result in an HTTP redirect when dereferenced. We expand on and apply this metric to TimeMaps for seven other URI-Rs of large Web sites and thirteen academic institutions. Using a ratio metric DI for the number of URI-Ms without redirects to those requiring a redirect when dereferenced, five of the eight large web sites' and two of the thirteen academic institutions' TimeMaps had a ratio of ratio less than one, indicating that more than half of the URI-Ms in these TimeMaps result in redirects when dereferenced.Comment: 43 pages, 8 figure

INDUCTION OF TOLERANCE TO HETEROLOGOUS PROTEINS AND THEIR CATABOLISM IN C57BL/6 MICE

C57BL/6 mice were rendered tolerant to one or another of 13 soluble protein antigens. Tolerance was induced by a single injection of 20 mg protein within 24 hours after birth. The duration of the unresponsive state was measured and compared with the rates of catabolism of the antigens as determined in adult and new born mice. The data presented fail to show a correlation between the persistence of labeled protein antigen and the duration of tolerance. In several occasions, even an inverse relationship between duration of the unresponsive state and persistence was demonstrated. The results, therefore, strongly indicate that the duration of tolerance is not dependent on the rates of catabolism of the antigens. Several of the commercial protein preparations used in this study contained minor impurities to which the animals were generally not rendered tolerant. By means of diffusion in agar techniques, it was demonstrated that mice injected at birth with a tolerance-inducing dose of antigen would generally not reveal precipitating antibodies to this antigen after the tolerant state had been abolished. A speculative explanation was given in terms of quantitative or qualitative differences of antibodies found in such animals as compared to the immunized control mice. After the 3rd or 4th day of life, newborn mice catabolized I131-labeled heterologous proteins at the same rates as adult mice. The apparent slow elimination during the first days of life was, at least in part, the result of retention of nonprotein-bound I131

Velocity Coefficients of the Reaction between Ethyl Iodide and Silver Nitrate in Ethyl and Methyl Alcohol and Mixtures of These Solvents

The study of chemical reactions in various solvents is one that has been occupying the attention of chemists for a long time, for by this means it is thought that we may in time gain a closer insight into the mechanism of chemical reactions in general. A reaction frequently studied is that between alkyl halides and silver nitrate

TERMINATION OF TOLERANCE TO HUMAN GAMMA GLOBULIN IN MICE BY ANTIGEN AND BACTERIAL LIPOPOLYSACCHARIDE (ENDOTOXIN)

Bacterial lipopolysaccharides (endotoxin) allowed the circumvention of the thymus-derived (T) cell helper function otherwise required for the antibody response in mice to human gamma globulin (HGG). In an analogous fashion, the state of tolerance to HGG, existing at a time when bone marrow-derived (B) cells had lost their unresponsiveness, could be terminated by the injection of both immunogenic HGG and endotoxin, but by neither given alone. However, no effect on tolerance to HGG could be observed when this regimen was followed at a time when B cells were tolerant. After the spontaneous recovery from tolerance in B cells, it seemed that specific priming was occurring in that population. This phenomenon was observed either by the injection of endotoxin and HGG or by the adoptive transfer of cells into irradiated hosts. These data have been discussed in the light of potential autoimmune manifestations that could theoretically follow a simultaneous gram-negative bacterial infection along with a release of self-antigen

Environmental chemical exposures and risk of herpes zoster.

This study investigated whether residence in Aberdeen, North Carolina, the location of the Aberdeen pesticides dumps site (a national priority list Superfund site containing organochlorine pesticides, volatile organic compounds, and metals), is associated with immune suppression as indicated by a higher incidence of herpes zoster and recent occurrences of other common infectious diseases. Study participants included 1,642 residents, 18-64 years of age, who responded to a telephone survey concerning potential occupational and recreational exposures to pesticides and other chemicals, lifetime history of herpes zoster (shingles), and the recent occurrence of other common infectious diseases. Stratified and logistic regression analyses were used to compare the cumulative incidence of herpes zoster among Aberdeen residents and residents of nearby communities. There was little evidence of an overall increased risk of herpes zoster among Aberdeen residents during the period 1951-1994 [relative risk (RR), 1.3; 95% confidence interval (CI), 0.8-2.1]. However, an elevated risk of herpes zoster was noted consistently among Aberdeen residents of younger ages as compared to residents of the nearby communities. The RR was 2.0 (CI, 1.0-4.0) among those 18-40 years of age and was not affected by controlling for potential confounders. The RR of herpes zoster was also consistently elevated in all age groups for the period before 1985. No differences were noted between residents of Aberdeen and those of the nearby communities with respect to the recent occurrence of other common infectious diseases. These results support the plausibility of an association between exposure to the Aberdeen pesticides dumps site and immune suppression and the potential use of herpes zoster as a marker of immune suppression in studies of environmental chemical exposures

The Kv2.1 K+ channel targets to the axon initial segment of hippocampal and cortical neurons in culture and in situ

<p>Abstract</p> <p>Background</p> <p>The Kv2.1 delayed-rectifier K⁺channel regulates membrane excitability in hippocampal neurons where it targets to dynamic cell surface clusters on the soma and proximal dendrites. In the past, Kv2.1 has been assumed to be absent from the axon initial segment.</p> <p>Results</p> <p>Transfected and endogenous Kv2.1 is now demonstrated to preferentially accumulate within the axon initial segment (AIS) over other neurite processes; 87% of 14 DIV hippocampal neurons show endogenous channel concentrated at the AIS relative to the soma and proximal dendrites. In contrast to the localization observed in pyramidal cells, GAD positive inhibitory neurons within the hippocampal cultures did not show AIS targeting. Photoactivable-GFP-Kv2.1-containing clusters at the AIS were stable, moving <1 <it>μ</it>m/hr with no channel turnover. Photobleach studies indicated individual channels within the cluster perimeter were highly mobile (FRAP <it>τ </it>= 10.4 ± 4.8 sec), supporting our model that Kv2.1 clusters are formed by the retention of mobile channels behind a diffusion-limiting perimeter. Demonstrating that the AIS targeting is not a tissue culture artifact, Kv2.1 was found in axon initial segments within both the adult rat hippocampal CA1, CA2, and CA3 layers and cortex.</p> <p>Conclusion</p> <p>In summary, Kv2.1 is associated with the axon initial segment both <it>in vitro </it>and <it>in vivo </it>where it may modulate action potential frequency and back propagation. Since transfected Kv2.1 initially localizes to the AIS before appearing on the soma, it is likely multiple mechanisms regulate Kv2.1 trafficking to the cell surface.</p