Policies on free primary and secondary education in East Africa: a review of the literature

Kenya, Tanzania and Uganda are among the countries in Sub-Saharan Africa which have recently implemented policies for free primary education, motivated in part by renewed democratic accountability following the re-emergence of multi-party politics in the 1990s. However, it is not the first time that the goal of expanding primary education has been pursued by these three neighbouring countries which have much in common. Since the 1960s, they have attempted to expand access at various levels of their education systems albeit with differences in philosophy and in both the modes and successes of implementation. All three countries continue to face the challenges of enrolling every child in school, keeping them in school and ensuring that meaningful learning occurs for all enrolled children. This paper provides an a review of the three countries’ policies for expanding access to education, particularly with regard to equity and the enrolment of excluded groups since their political independence in the 1960s. It considers policies in the light of the countries’ own stated goals alongside the broader international agendas set by the Millennium Development Goals and in particular, ‘Education for All’. It is concerned with the following questions: What led to those policies and how were they funded? What was the role, if any, of the international community in the formulation of those policies? What were the politics and philosophies surrounding the formulation of those policies, have the policies changed over time, and if so how and why? The paper also discusses the range of strategies for implementation adopted. Tremendous growth has occurred in access to primary education since the 1960s, not least in Kenya, Tanzania and Uganda. The challenge of providing equitable access to schooling has been addressed in a series of education drives with varying motivations, modalities and degrees of success, the most recent of which pays attention to the increasingly pressing question of the transition to secondary education. The success of such policy remains to be seen but will be crucial for the widening of access to the benefits of education and to economic opportunity, particularly for those groups which history has so far excluded

A Molecular Spiral Arm in the Far Outer Galaxy

We have identified a spiral arm lying beyond the Outer Arm in the first Galactic quadrant ~15 kpc from the Galactic center. After tracing the arm in existing 21 cm surveys, we searched for molecular gas using the CfA 1.2 meter telescope and detected CO at 10 of 220 positions. The detections are distributed along the arm from l = 13 deg, v = -21 km/s to l = 55 deg, v = -84 km/s and coincide with most of the main H I concentrations. One of the detections was fully mapped to reveal a large molecular cloud with a radius of 47 pc and a molecular mass of ~50,000 Mo. At a mean distance of 21 kpc, the molecular gas in this arm is the most distant yet detected in the Milky Way. The new arm appears to be the continuation of the Scutum-Centaurus Arm in the outer Galaxy, as a symmetric counterpart of the nearby Perseus Arm.Comment: 11 pages, 4 figures, 1 Table, ApJ Letters, in pres

OVI, NV and CIV in the Galactic Halo: II. Velocity-Resolved Observations with Hubble and FUSE

We present a survey of NV and OVI (and where available CIV) in the Galactic halo, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope (HST) along 34 sightlines. These ions are usually produced in nonequilibrium processes such as shocks, evaporative interfaces, or rapidly cooling gas, and thus trace the dynamics of the interstellar medium. Searching for global trends in integrated and velocity-resolved column density ratios, we find large variations in most measures, with some evidence for a systematic trend of higher ionization (lower NV/OVI column density ratio) at larger positive line-of-sight velocities. The slopes of log[N(NV)/N(OVI)] per unit velocity range from -0.015 to +0.005, with a mean of -0.0032+/-0.0022(r)+/-0.0014(sys) dex/(km/s). We compare this dataset with models of velocity-resolved high-ion signatures of several common physical structures. The dispersion of the ratios, OVI/NV/CIV, supports the growing belief that no single model can account for hot halo gas, and in fact some models predict much stronger trends than are observed. It is important to understand the signatures of different physical structures to interpret specific lines of sight and future global surveys.Comment: ApJ in press 43 pages, 22 fig

Deep Near-Infrared Imaging af an Embedded Cluster in the Extreme Outer Galaxy: Census of Supernovae Triggered Star Formation

While conducting a near-infrared (NIR) survey of ``Digel Clouds'', which are thought to be located in the extreme outer Galaxy (EOG), Kobayashi & Tokunaga found star formation activity in ``Cloud 2'', a giant molecular cloud at the Galactic radius of ~ 20 kpc. Additional infrared imaging showed two embedded young clusters at the densest regions of the molecular cloud. Because the molecular cloud is located in the vicinity of a supernova remnant (SNR) HI shell, GSH 138-01-94, it was suggested that the star formation activity in Cloud 2 was triggered by this expanding HI shell. We obtained deep J (1.25 um), H (1.65 um) and K (2.2 um) images of one of the embedded clusters in Cloud 2 with high spatial resolution (FWHM ~0".3) and high sensitivity (K ~ 20 mag, 10 sigma). We identified 52 cluster members. The estimated stellar density (~ 10 pc^{-2}) suggests that the cluster is a T-association. This is the deepest NIR imaging of an embedded cluster in the EOG. The observed K-band luminosity function (KLF) suggests that the underlying initial mass function (IMF) of the cluster down to the detection limit of ~ 0.1 M_sun is not significantly different from the typical IMFs in the field and in the near-by star clusters. The overall characteristics of this cluster appears to be similar to those of other embedded clusters in the far outer Galaxy. The estimated age of the cluster from the KLF, which is less than 1 Myr, is consistent with the view that the star formation was triggered by the HI shell whose age was estimated at 4.3 Myr (Stil & Irwin). The 3-dimensional geometry of SNR shell, molecular cloud and the embedded cluster, which is inferred from our data, as well as the cluster age strongly suggest that the star formation in Cloud 2 was triggered by the SNR shell.Comment: 19pages, 8 figures, 1 table, accepted to ApJ. Full paper (pdf) with high resolution figures available at http://www.ioa.s.u-tokyo.ac.jp/~ck_yasui/papers/Cloud2N_1.pd

Hydrogen and helium line formation in OB dwarfs and giants. A hybrid non-LTE approach

Aims: Hydrogen and helium line spectra are crucial diagnostic features for the quantitative analysis of OB stars. We compute synthetic spectra based on a hybrid non-LTE approach in order to test the ability of these models to reproduce high-resolution and high-S/N spectra of dwarf and giant stars and also to compare them with published grids of non-LTE (OSTAR2002) and LTE (Padova) models. Methods: Our approach solves the restricted non-LTE problem based on classical line-blanketed LTE model atmospheres. State-of-the-art model atoms and line-broadening theories are employed to model the H and He I/II spectra over the entire optical range and in the near-IR. Results: The synthetic spectra match almost all measurable hydrogen and helium lines observed in six test stars over a wide spectral range from the Balmer limit to the NIR, except for only a few well-understood cases. Our approach reproduces other published non-LTE calculations, however avoids inconsistencies with the modelling of the He I singlets recently discussed in the literature. It improves on the published LTE models in many aspects: non-LTE strengthening and the use of improved line-broadening data result in overall significant differences in the line profiles and equivalent widths of the Balmer and helium lines. Where possible, systematic effects on the stellar parameter determination are quantified, e.g. gravities derived from the Hgamma wings may be overestimated by up to ~0.2 dex at our upper temperature boundary in LTE. (abridged)Comment: 25 pages, 19 figures. Modified according to suggestions of the referee. Accepted for publication in A&A. Several figures in low resolution. A high-resolution pdf version of the preprint can be downloaded from http://www.sternwarte.uni-erlangen.de/~ai97/preprints/HHe_nieva.pd

Discovery of an Unbound Hyper-Velocity Star in the Milky Way Halo

We have discovered a star, SDSS J090745.0+024507, leaving the Galaxy with a heliocentric radial velocity of +853+-12 km/s, the largest velocity ever observed in the Milky Way halo. The star is either a hot blue horizontal branch star or a B9 main sequence star with a heliocentric distance ~55 kpc. Corrected for the solar reflex motion and to the local standard of rest, the Galactic rest-frame velocity is +709 km/s. Because its radial velocity vector points 173.8 deg from the Galactic center, we suggest that this star is the first example of a hyper-velocity star ejected from the Galactic center as predicted by Hills and later discussed by Yu & Tremaine. The star has [Fe/H]~0, consistent with a Galactic center origin, and a travel time of <80 Myr from the Galactic center, consistent with its stellar lifetime. If the star is indeed traveling from the Galactic center, it should have a proper motion of 0.3 mas/yr observable with GAIA. Identifying additional hyper-velocity stars throughout the halo will constrain the production rate history of hyper-velocity stars at the Galactic center.Comment: 4 pages, submitted to ApJ Letter

Numerical Testing of The Rare Earth Hypothesis using Monte Carlo Realisation Techniques

The Search for Extraterrestrial Intelligence (SETI) has thus far failed to provide a convincing detection of intelligent life. In the wake of this null signal, many "contact pessimistic" hypotheses have been formulated, the most famous of which is the Rare Earth Hypothesis. It postulates that although terrestrial planets may be common, the exact environmental conditions that Earth enjoys are rare, perhaps unique. As a result, simple microbial life may be common, but complex metazoans (and hence intelligence) will be rare. This paper uses Monte Carlo Realisation Techniques to investigate the Rare Earth Hypothesis, in particular the environmental criteria considered imperative to the existence of intelligence on Earth. By comparing with a less restrictive, more optimistic hypothesis, the data indicates that if the Rare Earth hypothesis is correct, intelligent civilisation will indeed be relatively rare. Studying the separations of pairs of civilisations shows that most intelligent civilisation pairs (ICPs) are unconnected: that is, they will not be able to exchange signals at lightspeed in the limited time that both are extant. However, the few ICPs that are connected are strongly connected, being able to participate in numerous exchanges of signals. This may provide encouragement for SETI researchers: although the Rare Earth Hypothesis is in general a contact-pessimistic hypothesis, it may be a "soft" or "exclusive" hypothesis, i.e. it may contain facets that are latently contact-optimistic.Comment: 13 pages, 10 figures, accepted for publication in the International Journal of Astrobiolog

The spatial distribution of O-B5 stars in the solar neighborhood as measured by Hipparcos

We have developed a method to calculate the fundamental parameters of the vertical structure of the Galaxy in the solar neighborhood from trigonometric parallaxes alone. The method takes into account Lutz-Kelker-type biases in a self-consistent way and has been applied to a sample of O-B5 stars obtained from the Hipparcos catalog. We find that the Sun is located 24.2 +/- 1.7 (random) +/- 0.4 (systematic) pc above the galactic plane and that the disk O-B5 stellar population is distributed with a scale height of 34.2 +/- 0.8 (random) +/- 2.5 (systematic) pc and an integrated surface density of (1.62 +/- 0.04 (random) +/- 0.14 (systematic)) 10^{-3} stars pc^{-2}. A halo component is also detected in the distribution and constitutes at least ~5% of the total O-B5 population. The O-B5 stellar population within ~100 pc of the Sun has an anomalous spatial distribution, with a less-than-average number density. This local disturbance is probably associated with the expansion of Gould's belt.Comment: 14 pages, 3 figures, to appear in the May 2001 issue of the Astronomical Journa

Metallicity in the Galactic Center: The Arches cluster

We present a quantitative spectral analysis of five very massive stars in the Arches cluster, located near the Galactic center, to determine stellar parameters, stellar wind properties and, most importantly, metallicity content. The analysis uses a new technique, presented here for the first time, and uses line-blanketed NLTE wind/atmosphere models fit to high-resolution near-infrared spectra of late-type nitrogen-rich Wolf-Rayet stars and OfI+ stars in the cluster. It relies on the fact that massive stars reach a maximum nitrogen abundance that is related to initial metallicity when they are in the WNL phase. We determine the present-day nitrogen abundance of the WNL stars in the Arches cluster to be 1.6% (mass fraction) and constrain the stellar metallicity in the cluster to be solar. This result is invariant to assumptions about the mass-luminosity relationship, the mass-loss rates, and rotation speeds. In addition, from this analysis, we find the age of the Arches cluster to be 2-2.5Myr, assuming coeval formation

Iron abundances from optical Fe III absorption lines in B-type stellar spectra

The role of optical Fe III absorption lines in B-type stars as iron abundance diagnostics is considered. To date, ultraviolet Fe lines have been widely used in B-type stars, although line blending can severely hinder their diagnostic power. Using optical spectra, covering a wavelength range ~ 3560 - 9200 A, a sample of Galactic B-type main-sequence and supergiant stars of spectral types B0.5 to B7 are investigated. A comparison of the observed Fe III spectra of supergiants, and those predicted from the model atmosphere codes TLUSTY (plane-parallel, non-LTE), with spectra generated using SYNSPEC (LTE), and CMFGEN (spherical, non-LTE), reveal that non-LTE effects appear small. In addition, a sample of main-sequence and supergiant objects, observed with FEROS, reveal LTE abundance estimates consistent with the Galactic environment and previous optical studies. Based on the present study, we list a number of Fe III transitions which we recommend for estimating the iron abundance from early B-type stellar spectra.Comment: 3 figures and 8 tables. Table 3 is to be published online only (included here on last page). Accepted for publication in MNRA