On two species of cichlid fishes from the Malagarazi River (Tanganyika), with notes on the pharyngeal apophysis in species of the Haplochromis group

The material described in this paper was collected during a survey of the fish and fisheries of the Malagarazi River and swamps carried out in August and September, 1952, by members of the East African Fisheries Research Organisation and the Inland Fisheries Officer (Kigoma). Previous records of Cichlid fishes from the Malagarazi River have been published by David (1937) and Poll (1946 and 1948). These included Haplochromis burtoni (Ganither)'and H. malagaraziensis David from the upper reaches of the river, and Tilapia karomo Poll from the delta. The present collection was made at Uvinza and Iragala on the open river and at Katare on one of the numerous swamps. Besides the one new species described below, Horei burtoni and H. horei were collected at Irangala, and a species of Serranochromis at Uvinza and Katare. Two apparently new species of Haplochromis were collected in all three areas and will be described at a later date

The fishes of Uganda

The fishes of Uganda have been subject to considerable study. Apart from many purely descriptive studies of the fishes themselves, three reports have been published which deal with the ecology of the lakes in relation to fish and fisheries (Worthington (1929a, 1932b): Graham (1929)). Much of the literature is scattered in various scientific journals, dating back to the early part of the century and is difficult to obtain in Uganda. The more recent reports also are out of print and virtually un obtainable. The purpose of this present survey is to bring together the results of these many researches and to present, in the light of recent unpublished information, an account of the taxonomy and biology of the many fish species which are to be found in the lakes and rivers of Uganda. Particular attention has been paid to the provision of keys, so that most of the Fishes may be easily identified

Quaternary Fish-Fossils

Fish-remains collected from deposits at Ishango (Lake Edward) and the Semliki valley by Dr. J. DE HEINZELIN'S 1960 expedition, have increased considerably our historical knowledge of East African fishes. The collections are of especial value since their temporal range extends over the entire Pleistocene period, a time when the great lakes of Africa were undergoing extensive topographical changes and their faunae were subject to the vicissitudes of changing climate and hydrography. Indeed, the Pleistocene may be looked upon as a critical phase in the evolution of the present-day East African fish-fauna from an earlier and possibly pan-African type. Many taxonomists and evolutionists have been attracted by the biogeographical problems which these lakes present. But, attempts to explain the often curious distribution of families and genera within the area have been hampered by the lack of an adequate palaeontological background

Evolution and speciation in the Haplochromis (Pisces, Cichlidae) of Lake Victoria

The species flock of cichlid fishes in Lake Victoria comprises two endemic Tilapia, about seventy endemic Haplochromis and four endemic monotypic genera with strong aplochromis affinities. In addition there are six Haplochromis and one monotypic genus with a somewhat wider distribution; however, only one of these species, the nilotic H. multicolor, extends beyond the Edward-Victoria drainage basins. The smaller Haplochromis species flocks in Lakes Edward and Kivu are closely related to that of Victoria, but even including these species the whole complex shows less taxonomic, morphological and ecological diversity than the flocks of Haplochromis and Haplochromis-like species in Lake Nyasa

Fish remains from the Mumba Cave, Lake Eyasi

Through the courtesy of Dr. U. LEHMANN of the Geologisches Staatsinstitut, Hamburg, I have been able to examine the fish remains collected froPl the Mumba Cave by Professor KOHL-LARSEN'S 1938 expedition. Fish remains were obtained from the third (Homo sapiens; late Stone Age) and fifth ('Africanthropus'; Stillbay) strata, and comprise vertebrae, neurocranial fragments and fin spines. The majority are slightly mineralized (as measured by their hardness and weight) and are lightly coloured, but a small proportion are dark brown in colour and are more heavily mineralized. Fossils from anyone depth usually show some intergradation in hardness and coloration, but specimens in the "pale-soft" category predominate. In general, the bones are well preserved and consequently a high proportion (over 98%) can be identified generically. But, since specific characters are not clearly reflected in any of the elements preserved, it is impossible to name the species present

The role of geometry changes and debris formation associated with wear on the temperature field in fretting contacts

The temperature of a fretting contact is known to be a key factor in its development. However, as a test proceeds, the wear scar changes, both geometrically and through the formation of oxide-based debris-beds. Accordingly, the effects of these on the near-surface temperature field resulting from frictional heating in fretting has been analysed via numerical modelling. Under the test conditions examined, it was predicted that (i) the development of the wear scar geometry would result in a significant (up to ~ 25%) reduction in the mean-surface temperature rise, and (ii) the formation of a typical oxide debris bed would result in a significant (up to ~ 80%) increase in the mean-surface temperature rise

A solution of the coincidence problem based on the recent galactic core black hole mass density increase

A mechanism capable to provide a natural solution to two major cosmological problems, i.e. the cosmic acceleration and the coincidence problem, is proposed. A specific brane-bulk energy exchange mechanism produces a total dark pressure, arising when adding all normal to the brane negative pressures in the interior of galactic core black holes. This astrophysically produced negative dark pressure explains cosmic acceleration and why the dark energy today is of the same order to the matter density for a wide range of the involved parameters. An exciting result of the analysis is that the recent rise of the galactic core black hole mass density causes the recent passage from cosmic deceleration to acceleration. Finally, it is worth mentioning that this work corrects a wide spread fallacy among brane cosmologists, i.e. that escaping gravitons result to positive dark pressure.Comment: 14 pages, 3 figure

The role of frictional power dissipation (as a function of frequency) and test temperature on contact temperature and the subsequent wear behaviour in a stainless steel contact in fretting

Temperature is known to affect the fretting wear behaviour of metals; generally, a critical temperature is observed, above which there are substantial reductions in wear rate, with these being associated with the development of protective oxide beds in the fretting contact. This work has examined the gross sliding fretting behaviour of a stainless steel as a function of bulk temperature and fretting frequency(with changes in the fretting frequency altering the frictional power dissipated in the contact amongst other things). An analytical model has been developed which has suggested that at 200 Hz, an increase in the contact temperature of more than 70°C can be expected, associated with the high frictional power dissipation at this frequency (compared to that dissipated at a fretting frequency of 20 Hz). With the bulk temperature at either room temperature or 275°C, the increase in contact temperature does not result in a transition across the critical temperature (and thus fretting behaviour at these temperatures is relatively insensitive to fretting frequency). However, with a bulk temperature of 150°C, the increase in temperature associated with the increased frictional power dissipation at the higher frequency results in the critical temperature being exceeded, and in significant differences in fretting behaviour

A multilevel neo-institutional analysis of infection prevention and control in English hospitals: coerced safety culture change?

Despite committed policy, regulative and professional efforts on healthcare safety, little is known about how such macro-interventions permeate organisations and shape culture over time. Informed by neo-institutional theory, we examined how inter-organisational influences shaped safety practices and inter-subjective meanings following efforts for coerced culture change. We traced macro-influences from 2000 to 2015 in infection prevention and control (IPC). Safety perceptions and meanings were inductively analysed from 130 in-depth qualitative interviews with senior- and middle-level managers from 30 English hospitals. A total of 869 institutional interventions were identified; 69% had a regulative component. In this context of forced implementation of safety practices, staff experienced inherent tensions concerning the scope of safety, their ability to be open and prioritisation of external mandates over local need. These tensions stemmed from conflicts among three co-existing institutional logics prevalent in the NHS. In response to requests for change, staff flexibly drew from a repertoire of cognitive, material and symbolic resources within and outside their organisations. They crafted 'strategies of action', guided by a situated assessment of first-hand practice experiences complementing collective evaluations of interventions such as 'pragmatic', 'sensible' and also 'legitimate'. Macro-institutional forces exerted influence either directly on individuals or indirectly by enriching the organisational cultural repertoire

Search for the standard model Higgs boson decaying to a bbˉb\bar{b} pair in events with no charged leptons and large missing transverse energy using the full CDF data set

We report on a search for the standard model Higgs boson produced in association with a vector boson in the full data set of proton-antiproton collisions at $\sqrt{s} = 1.96$ TeV recorded by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45 fb$^{-1}$. We consider events having no identified charged lepton, a transverse energy imbalance, and two or three jets, of which at least one is consistent with originating from the decay of a $b$ quark. We place 95% credibility level upper limits on the production cross section times standard model branching fraction for several mass hypotheses between 90 and $150 \mathrm{GeV}/c^2$. For a Higgs boson mass of $125 \mathrm{GeV}/c^2$, the observed (expected) limit is 6.7 (3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let