Restarting Automata with Auxiliary Symbols and Small Lookahead

We present a study on lookahead hierarchies for restarting automata with auxiliary symbols and small lookahead. In particular, we show that there are just two different classes of languages recognised RRWW automata, through the restriction of lookahead size. We also show that the respective (left-) monotone restarting automaton models characterise the context-free languages and that the respective right-left-monotone restarting automata characterise the linear languages both with just lookahead length 2.Comment: Full version of the paper accepted to LATA 201

Age at first dose of measles vaccination in Ethiopia

Background: Although measles vaccination is recommended to be given at nine months of age in Ethiopia and in most of sub-Saharan Africa, no information is available about the age at which children actually receive their first dose of measles vaccine. This has important implications in terms of preventing infection and averting epidemics of measles. Objective: To determine the age at which Ethiopian children actually receive their first dose of measles vaccine. Design: Cross sectional study. Setting: All major vaccination facilities including private and non-governmental health facilities that were registered with the Addis Ababa city Administration Health Bureau. Subjects: A total of 17,674 records of children who received measles vaccination in health facilities were reviewed and in rural areas 615 children were surveyed over one year period September 2004 to August 2005. Results: In both the urban and the rural settings the median age of children at first dose of measles vaccination was nine months. In the rural areas only 19.8% of children had vaccination cards. Measles coverage by card and history in rural areas was 84.4%. Many children from the rural site received measles vaccination during supplemental immunisation activities (SIAs) rather than from routine vaccination programmes. Measles coverage significantly varies among sub-cities in Addis Ababa. Conclusion: Vaccination practices and measles coverage levels do not support delaying the first measles vaccine dose. Strengthening the routine vaccination programmes must receive priority before changing recommended age for the first dose of measles vaccine

Serum Amyloid P Component (SAP)-Like Protein From Botryllid Ascidians Provides a Clue to Amyloid Function

The HA-1 lectin isolated from Botrylloides leachii has an amino acid composition similar to that of mammalian serum amyloid protein (SAP). SAP is a universal component of mammalian amyloid deposits. Like SAP, HA-1 has a disc ultrastructure, and antibody to HA-1 binds both (a) to amyloidlike fibers deposited between rejected Botrylloides colonies and (b) to cerebral amyloid deposits in Alzheimer's disease brains. Deposition of protochordate amyloid within rejection sites and surrounding fouling organisms implies that these fibers function as barriers to allogeneic and infectious challenge. Similarly, mammalian amyloid may also function to contain inflammatory lesions and to limit the spread of certain infections. Pathological amyloidotic conditions in humans, such as Alzheimer's disease, may result from unregulated expression of this primitive encapsulation response

Electronic interactions in fullerene spheres

The electron-phonon and Coulomb interactions inC$_{60}$, and larger fullerene spheres are analyzed. The coupling between electrons and intramolecular vibrations give corrections $\sim 1 - 10$ meV to the electronic energies for C$_{60}$, and scales as $R^{-4}$ in larger molecules. The energies associated with electrostatic interactions are of order $\sim 1 - 4$ eV, in C$_{60}$ and scale as $R^{-1}$. Charged fullerenes show enhanced electron-phonon coupling, $\sim 10$ meV, which scales as $R^{-2}$. Finally, it is argued that non only C$_{60}^{-}$, but also C$_{60}^{--}$ are highly polarizable molecules. The polarizabilities scale as $R^3$ and $R^4$, respectively. The role of this large polarizability in mediating intermolecular interactions is also discussed.Comment: 12 pages. No figure

The Role of Rab3a in Secretory Vesicle Docking Requires Association/Dissociation of Guanidine Phosphates and Munc18-1

Rab3a is a small GTPase that binds selectively to secretory vesicles and switches between active, GTP-bound and inactive, GDP-bound conformations. In yeast, Rab and SM-genes interact genetically to promote vesicle targeting/fusion. We tested different Rab3a conformations and genetic interactions with the SM-gene munc18-1 on the docking function of Rab3a in mammalian chromaffin cells. We expressed Rab3a mutants locked in the GTP- or GDP-bound form in wild-type and munc18-1 null mutant cells and analyzed secretory vesicle distribution. We confirmed that wild-type Rab3a promotes vesicle docking in wild-type cells. Unexpectedly, both GTP- and GDP-locked Rab3a mutants did not promote docking. Furthermore, wild-type Rab3a did not promote docking in munc18-1 null cells and GTP- and GDP-Rab3a both decreased the amount of docked vesicles. The results show that GTP- and GDP-locked conformations do not support a Munc18-1 dependent role of Rab3a in docking. This suggests that nucleotide cycling is required to support docking and that this action of Rab3a is upstream of Munc18-1

Age At First Dose Of Measles Vaccination In Ethiopia

Background: Although measles vaccination is recommended to be given at nine months ofage in Ethiopia and in most of sub-Saharan Africa, no information is available about theage at which children actually receive their first dose of measles vaccine. This has importantimplications in terms of preventing infection and averting epidemics of measles.Objective: To determine the age at which Ethiopian children actually receive their first doseof measles vaccine.Design: Cross sectional study.Setting: All major vaccination facilities including private and non-governmental healthfacilities that were registered with the Addis Ababa city Administration Health Bureau.Subjects: A total of 17,674 records of children who received measles vaccination in healthfacilities were reviewed and in rural areas 615 children were surveyed over one year periodSeptember 2004 to August 2005.Results: In both the urban and the rural settings the median age of children at first dose ofmeasles vaccination was nine months. In the rural areas only 19.8% of children had vaccinationcards. Measles coverage by card and history in rural areas was 84.4%. Many children from therural site received measles vaccination during supplemental immunisation activities (SIAs)rather than from routine vaccination programmes. Measles coverage significantly variesamong sub-cities in Addis Ababa.Conclusion: Vaccination practices and measles coverage levels do not support delaying thefirst measles vaccine dose. Strengthening the routine vaccination programmes must receivepriority before changing recommended age for the first dose of measles vaccine

V(D)J Recombination and the Evolution of the Adaptive Immune System

In order for the immune system to generate its vast numbers of receptors, B- and T-cell receptor genes are created by recombining preexisting gene segments. This well- coordinated set of reactions is explaine

Nonperturbative approach to the Hubbard model in C60 cluster

We propose a computational scheme for the Hubbard model in the C60 cluster in which the interaction with the Fermi sea of charges added to the neutral molecule is switched on sequentially. This is applied to the calculation of the balance of charging energies, within a low-energy truncation of the space of states which produces moderate errors for an intermediate range of the interaction strength.Comment: 5 pages, Revtex, 2 figure

The genetic architecture of divergence between threespine stickleback species.

The genetic and molecular basis of morphological evolution is poorly understood, particularly in vertebrates. Genetic studies of the differences between naturally occurring vertebrate species have been limited by the expense and difficulty of raising large numbers of animals and the absence of molecular linkage maps for all but a handful of laboratory and domesticated animals. We have developed a genome-wide linkage map for the three-spined stickleback (Gasterosteus aculeatus), an extensively studied teleost fish that has undergone rapid divergence and speciation since the melting of glaciers 15,000 years ago. Here we use this map to analyse the genetic basis of recently evolved changes in skeletal armour and feeding morphologies seen in the benthic and limnetic stickleback species from Priest Lake, British Columbia. Substantial alterations in spine length, armour plate number, and gill raker number are controlled by genetic factors that map to independent chromosome regions. Further study of these regions will help to define the number and type of genetic changes that underlie morphological diversification during vertebrate evolution

Temporally consistent species differences in parasite infection but no evidence for rapid parasite-mediated speciation in Lake Victoria cichlid fish

Abstract Parasites may have strong eco-evolutionary interactions with their hosts. Consequently, they may contribute to host diversification. The radiation of cichlid fish in Lake Victoria provides a good model to study the role of parasites in the early stages of speciation. We investigated patterns of macroparasite infection in a community of 17 sympatric cichlids from a recent radiation and 2 older species from 2 non-radiating lineages, to explore the opportunity for parasite-mediated speciation. Host species had different parasite infection profiles, which were only partially explained by ecological factors (diet, water depth). This may indicate that differences in infection are not simply the result of differences in exposure, but that hosts evolved species-specific resistance, consistent with parasite-mediated divergent selection. Infection was similar between sampling years, indicating that the direction of parasite-mediated selection is stable through time. We morphologically identified 6 Cichlidogyrus species, a gill parasite that is considered a good candidate for driving parasite-mediated speciation, because it is host species-specific and has radiated elsewhere in Africa. Species composition of Cichlidogyrus infection was similar among the most closely related host species (members of the Lake Victoria radiation), but two more distantly related species (belonging to non-radiating sister lineages) showed distinct infection profiles. This is inconsistent with a role for Cichlidogyrus in the early stages of divergence. To conclude, we find significant interspecific variation in parasite infection profiles, which is temporally consistent. We found no evidence that Cichlidogyrus-mediated selection contributes to the early stages of speciation. Instead, our findings indicate that species differences in infection accumulate after speciation.Peer reviewe