Domestic tourist travel patterns in New Zealand

Recent emphasis on the growth in overseas arrivals has overshadowed domestic tourism which, nevertheless, remains a very significant social and economic activity in New Zealand. This paper analyses the geographical dimensions of tourist travel using data from the Domestic Travel Study. Once broad national trends are identified, inter-regional travel patterns are examined using dominant flow analysis and regional profiles are established by means of ternary graphs. This analysis shows the dominance of the major metropolitan markets, the regionalized nature of much domestic tourism and regional variations in visitor profiles. Regional population size plays a major role in determining overall flows but what appears to make the difference between a net loss or gain in total bednights is a region's ability to attract holiday visitors. This underscores the value which the promotion of domestic tourism may have in regional development.     

Natural resource management and anti-desertification policy in the Sahel-Sudan zone: A case study of gum arabic

The philosophy of sustainable development argues that environmental conservation and economic development are complementary objectives in national economic planning. This contrasts with the more traditional view that development leads to inevitable sacrifies in envitronmental quality. This case study investigates a clear example of complementary in the Sahel-Sudan zone through an analysis of the economics of planting Acacia senegal to produce gum hashab (gum arabic). A. senegal has many environmentally benign functions besides producing gum as a cash crop. It is leguminous, stabilises soils, provides fodder and firewood and effevtively provides a buffer against desertification. Nonetheless, the gum arabic belt is suffering increased degradation due to drought, population movement and, in the past, wrong economic incentives to farmers. Economic incentives have recently improved and the paper offers a partial cost-benefit analysis of A. senegal production to show that planting can achieve high economic rates of return.This paper was presented to the International Task Force on Human Investment and Resource Use, UNESCO, Paris, March 1988, under the UNESCO Man and the Biosphere (MAB) programme.     

On the applicability of lunar breccias for paleomagnetic interpretations

Many of the breccias returned by the Apollo missions are capable of acquiring a substantial viscous remanent magnetization (VRM) which is of two forms. The first one has an upper limit to the relaxation times of about 100 to 1000min which corresponds to a grain diameter of about 145 Å. This suggests that the maximum relaxation time is determined by the transition from superparamagnetic to stable single domain particles. The second form of VRM follows the classical logt dependence typical for multidomain grains with a wide distribution of relaxation times. Hysteresis loop measurements yield the same kind of grain size distributions. In addition the analysis shows a fivefold enrichment of native iron in the breccias and soils as compared to the igneous rocks. In spite of a large VRM some breccias contain a stable remanent magnetization. Its intensity is typically 10^–6emu/gm, the same value found for igneous rocks. It is possible, therefore, to use some of the breccias to reconstruct the history of the lunar magnetic field.     

The violent past of Cygnus X-2

Cygnus X-2 appears to be the descendant of an intermediate-mass X-ray binary (IMXB). Using Mazzitelli's stellar code we compute detailed evolutionary sequences for the system and find that its prehistory is sensitive to stellar input parameters, in particular the amount of core overshooting during the main-sequence phase. With standard assumptions for convective overshooting a case B mass transfer starting with a 3.5-M_⊙ donor star is the most likely evolutionary solution for Cygnus X-2. This makes the currently observed state rather short-lived, of order 3 Myr, and requires a formation rate > 10⁻⁷–10⁻⁶ yr⁻¹ of such systems in the Galaxy. Our calculations show that neutron star IMXBs with initially more massive donors (≳4 M_⊙) encounter a delayed dynamical instability; they are unlikely to survive this rapid mass transfer phase. We determine limits for the age and initial parameters of Cygnus X-2 and calculate possible dynamical orbits of the system in a realistic Galactic potential, given its observed radial velocity. We find trajectories which are consistent with a progenitor binary on a circular orbit in the Galactic plane inside the solar circle that received a kick velocity ≤200 km s⁻¹ at the birth of the neutron star. The simulations suggest that about 7 per cent of IMXBs receiving an arbitrary kick velocity from a standard kick velocity spectrum would end up in an orbit similar to Cygnus X-2, while about 10 per cent of them reach yet larger Galactocentric distances.