Evolution of local recruitment and its consequences for marine populations

Advantages of dispersal on the scales that are possible in a long pelagic larval period are not apparent, even for benthic species. An alternative hypothesis is that wide dispersal may be an incidental byproduct of an ontogenetic migration from and then back to the parental habitat. Under this hypothesis, the water column is a better habitat than the bottom for early development. Because the parental area is often an especially favorable habitat for juveniles and adults, selection may even favor larval retention or larval return rather than dispersal. Where larval capabilities and currents permit, a high percentage of recruits may then be produced from local adults. Expected consequences of a high proportion of local recruitment are stronger links between stock and recruitment, greater vulnerability to recruitment overfishing and local modifications of habitat, greater local benefits from fishery reserves, and possibly more localized adaptation within populations. Export of some larvae is consistent with a high proportion of retained or returning larvae, could stabilize populations linked by larval exchange, and provide connectivity between marine reserves. Even a small amount of larval export could account for the greater gene flow, large ranges, and long evolutionary durations seen in species with long pelagic larval stages.

Program sustainability of a community-based intervention to prevent falls among older Australians

Multi-strategy interventions have been demonstrated to prevent falls among older people, but studies have not explored their sustainability. This paper investigates program sustainability of Stay on Your Feet (SOYF), an Australian multi-strategy falls prevention program (1992-1996) that achieved a significant reduction in falls-related hospital admissions. A series of surveys assessed recall, involvement and current falls prevention activities, 5 years post-SOYF in multiple original SOYF stakeholder groups within the study area [general practitioners (GPs), pharmacists, community health (CH) staff shire councils (SCs) and access committees (ACs)]. Focus groups explored possible behavioural changes in the target group. Surveys were mailed, except to CH staff and ACs. who participated in guided group sessions and were contacted via the telephone, respectively. Response rates were: GPs. 67% (139/209); pharmacists, 79% (53/67); CH staff, 63% (129/204); SCs, 90% (9/10); ACs, 80% (8/10). There were 73 older people in eight focus groups. Of 117 GPs who were practising during SOYF 80% recalled SOYF and 74% of these reported an influence on their practice. Of 46 pharmacists operating a business during SOYF, 45% had heard of SOYF and 79% of these reported being 'somewhat' influenced. Of 76 community health staff (59%) in the area at that time, 99% had heard of SOYF and 82% reported involvement. Four SCs retained a SOYF resource, but none thought current activities were related. Seven ACs reported involvement, but no activities were sustained. Thirty-five focus group participants (48%) remembered SOYF and reported a variety of SOYF-initiated behaviour changes. Program sustainability was clearly demonstrated among health practitioners. Further research is required to assess long-term effect sustainability.

Local inflammation is crucial for T cell mediated rejection of skin graft expressing foreign antigen

Most of the skin grafts from (K14hGH.FVB C57BL/6) F1 mice, which express foreign antigen (human growth hormone, hGH) in skin keratinocytes driven by keratin 14 promoter, were spontaneously rejected by syngeneic wild type F1 recipients and hGH-specific immune responses such as antibody and hGHspecific T cells were generated in these recipients. Interestingly, a 2nd F1 hGH-expressing skin graft was rejected by graft primed recipients, but was not rejected from such recipients if CD4+ or CD8+ T cells were depleted prior to the placement of the 2nd graft. Surprisingly, this 2nd graft retained healthy even after CD4+ or CD8+ T cells were allowed to recover so that the animal could reject a freshly placed 3rd F1 hGH-expressing graft. Furthermore, inflammatory response induced by topical treatment with imiquimod could lead to the rejection of some well-healed 2nd grafts. This result indicates that both CD4+ and CD8+ T cells are required for the rejection and the ability of effector T cells to reject a graft is determined by local factors in the graft which are presumably determined by inflammation induced by surgery or imiquimod treatment. Taken together, our results suggest that in addition to CD4+ and CD8+ T cells, local environmental factors induced by inflammation are also crucial for effector T cell functions leading to graft destruction. The understanding of these local factors will lead to more effective immunotherapy for established, epithelial cancer in the future.

State sector reform and agriculture in China

China's state sector reform process is examined through the key sector of agriculture. A preview of aggregate statistics and broader reform measures indicate the declining role of the state. However, a systematic analysis of administrative, service and enterprise structures reveal the nuances of how the state has retained strong capacity to guide development of the agricultural sector. State and Party policy makers aim not only to support the livelihoods of hundreds of millions of farmers, but also to pursue agricultural modernization in the context of rapid industrialization. These goals are unlikely to be achieved through a wholesale transfer of functions to the private sector, so the state has maintained or developed new mechanisms of influence, particularly in the areas of service provision and enterprise development.

A transformation toughening white cast iron

An experimental white cast iron with the unprecedented fracture tough ness of 40 MPa m(1/2) is currently being studied to determine the mechanisms of toughening. This paper reports the investigation of the role of strain-induced martensitic (SIM) transformation. The dendritic microconstituent in the toughened alloy consists primarily of retained austenite, with precipitated M(7)C(3) carbides and some martensite. Refrigeration experiments and differential scanning calorimetry (DSC) were used to demonstrate, firstly, that this retained austenite has an ''effective'' sub-ambient M(S) temperature and, secondly, that SIM transformation can occur at ambient temperatures. Comparison between room temperature and elevated temperature K-Ic tests showed that the observed SIM produces a transformation toughening response in the alloy, contributing to, but not fully accounting for, its high tough ness. SIM as a mechanism for transformation toughening has not previously been reported for white cast irons. Microhardness traverses on crack paths and X-ray diffraction (XRD) on fracture surfaces confirmed the interpretation of the K-Ic experiments. Further DSC and quantitative XRD showed that, as heat-treatment temperature is varied, there is a correlation between fracture toughness and the volume fraction of unstable retained austenite.

The subfamily Aephnidiogeninae Yamaguti, 1934 (Digenea: Lepocreadiidae), its status and that of the genera Aephnidiogenes Nicoll, 1915, Holorchis Stossich, 1901, Austroholorchis n g, Pseudaephnidiogenes Yamaguti, 1971, Pseudoholorchis Yamaguti, 1958 and N

The status of all of the putative member genera of the subfamily Aephnidiogeninae is reconsidered, based mainly on the morphology of the terminal genitalia, Aephnidiogenes Nicoll, 1915 is the only genus retained in the Aaephnidiogeninae. Aephnidiogenes major Yamaguti, 1934 from Diagramma labiosum from the southern Great Barrier Reef is redescribed with particular reference to the terminal genitalia, and is shown to lack a true cirrussac, a condition considered to be diagnostic of the Aephnidiogeninae. Holorchis Stossich, 1901 is placed in the subfamily Lepidapedinae. Holorchis pycnoporus Stossich, 1901 from Pagellus acarne from off Spanish Sahara and from Diplodus vulgaris from off Italy and H. legendrei Dollfus, 1946 from Sparodon durbanensis and D. sargus from off eastern Cape Province, South Africa and from Pagellus erythrinus from the Adriatic Sea and Italy are studied and illustrated. The terminal genitalia of H. pycnoporus are found to be enigmatic, but those of H. legendrei are found to fit clearly into the 'Lepidapedon-like' pattern. A new genus Austroholorchis is erected in the Lepidapedinae, with A. sprenti (Gibson, 1987) n. comb. as the type-species. Its diagnostic features are its ani, infundibuliform oral sucker and the position of the ovary at about mid-level of the uterus. A. sprenti is illustrated, its hosts in Queensland waters being Sillago maculata, S, analis and S. ciliata. A, levis n. sp. is described from Sillago bassensis from south-western Western Australia. The genus Pseudaephnidiogenes Yamaguti, 1971 is placed in the Lepidapedinae. P. rhabdosargi (Prudhoe, 1956) from Rhabdosargus sarba from off Natal, South Africa is illustrated and the terminal genitalia of P. rhabdosargi from R. sarba and from R. holubi from off eastern Cape Province and Pseudaephnidiogenes vossi Bray, 1985 from Caffrogobius nudiceps from off eastern Cape Province, South Africa are illustrated. The genus Pseudoholorchis Yamaguti, 1958 is placed in the subfamily Lepocreadiinae. The terminal genitalia of P. pulcher (Manter, 1954) from Latridopsis ciliaris from New Zealand are illustrated, The genus Neolepocreadium Thomas, 1960 is placed in the Lepocreadiidae.

Structure of TcpG, the DsbA protein folding catalyst from Vibrio cholerae

The efficient and correct folding of bacterial disulfide bonded proteins in vivo is dependent upon a class of periplasmic oxidoreductase proteins called DsbA, after the Escherichia coli enzyme. In the pathogenic bacterium Vibrio cholerae, the DsbA homolog (TcpG) is responsible for the folding, maturation and secretion of virulence factors. Mutants in which the tcpg gene has been inactivated are avirulent; they no longer produce functional colonisation pill and they no longer secrete cholera toxin. TcpG is thus a suitable target for inhibitors that could counteract the virulence of this organism, thereby preventing the symptoms of cholera. The crystal structure of oxidized TcpG (refined at a resolution of 2.1 Angstrom) serves as a starting point for the rational design of such inhibitors. As expected, TcpG has the same fold as E. coli DsbA, with which it shares similar to 40% sequence identity. Ln addition, the characteristic surface features of DsbA are present in TcpG, supporting the notion that these features play a functional role. While the overall architecture of TcpG and DsbA is similar and the surface features are retained in TcpG, there are significant differences. For example, the kinked active site helix results from a three-residue loop in DsbA, but is caused by a proline in TcpG (making TcpG more similar to thioredoxin in this respect). Furthermore, the proposed peptide binding groove of TcpG is substantially shortened compared with that of DsbA due to a six-residue deletion. Also, the hydrophobic pocket of TcpG is more shallow and the acidic patch is much less extensive than that of E. coli DsbA. The identification of the structural and surface features that are retained or are divergent in TcpG provides a useful assessment of their functional importance in these protein folding catalysts and is an important prerequisite for the design of TcpG inhibitors. (C) 1997 Academic Press Limited.

Transmission electron microscopy of a transformation toughened white cast iron

Transmission electron microscopy has been used to study the microstructure of an experimental white cast iran, in which a combination of modified alloy composition and unconventional heat treatment has resulted in a fracture toughness of 40 MPa m(-1/2). Microstructural features of the alloy that contribute to the toughness improvement and hence distinguish it from conventional white irons have been investigated. In the as-cast condition the dendrites are fully austenitic and the eutectic consists of M7C3 carbides and martensite. During heat treatment at 1130 degrees C the austenite is partially destabilized by precipitation of chromium-rich M7C3 carbides. This results in a dendritic microconstituent consisting of bulk retained austenite and secondary carbides which are sheathed with martensite. The martensite sheaths, which contain interlath films of retained austenite, are irregular in shape with some laths extending into the bulk retained austenite. Emphasis has been placed on the morphology, distribution, and stability of the retained austenite and its transformation products in the dendrites. The implications of these findings on the transformation toughening mechanism in this alloy are discussed.

Consequences of traumatic injury in fossil and recent dipnoan dentitions

Traumatic injury to the dentition of dipnoans, indirectly as a result of jaw fracture, or directly from damage to the tooth tissues, is present throughout the history of this group, in fossil and in Recent material. Bones heal, but traces of the injury are retained in the tooth tissues, permanently if the proliferative regions of the tooth plate are injured, or until the damaged dentines are removed by wear if the growing regions are left intact. Lack of resorption and repair of damaged dental hard tissues in dipnoans has implications for some models of tooth plate growth in lungfish with a permanent dentition, because this indicates that lungfish tooth plates may not have the capacity to form reparative dentine as part of the normal growth processes.

Distribution of C-14 Cylindrospermopsin in vivo in the mouse

Radiolabelled C-14 cylindrospermopsin (CYN) has been prepared and used to investigate the distribution and excretion of CYN in vivo in male Quackenbush mice. At a dose of 0.2 mg/kg (i.e., approx. median lethal dose) the following mean (SID) urinary and faecal recoveries (cumulative) were obtained, respectively: (0-6 hours, n = 4) 48.2 (29.3)%, 11.9 (21.4)%; (0-12 hours, n = 12) 66.0 (27.1)%, 5.7 (5.6)%; (0-24 hours, n = 12) 68.4 (26.7)%, 8.5 (8.1)%. Mean (SD) recoveries from livers at 6 hours were 20.6 (6.4)% (n = 4), at 48 hours 13.1 (7.7)% (n = 8), and 5-7 days were 2.1 (2.1)% (n = 8). A substantial amount (up to 23%) can be retained in the liver for up to 48 hours with a lesser amount retained in the kidneys. The excretion patterns show substantial interindividual variability between predominantly faecal or urinary excretion, but these patterns are not related in any simple manner to the outcome in terms of toxicity. There is at least one methanol-extractable metabolite as well as a nonmethanol-extractable metabolite in the liver. The methanol-extractable metabolite was not found in the kidney and is more hydrophilic than CYN itself on reverse phase. (C) 2001 by John Wiley & Sons, Inc.

Tidal effects on groundwater dynamics in unconfined aquifers

The variation of seawater level resulting from tidal fluctuations is usually neglected in regional groundwater flow studies. Although the tidal oscillation is damped near the shoreline, there is a quasi-steady-slate rise in the mean water-table position, which may have an influence on regional groundwater flow. In this paper the effects of tidal fluctuations on groundwater hydraulics are investigated using a variably saturated numerical model that includes the effects of a realistic mild beach slope, seepage face and the unsaturated zone. In particular the impact of these factors on the velocity field in the aquifer is assessed. Simulations show that the tidal fluctuation has substantial consequences for the local velocity field in the vicinity of the exit face, which affects the nearshore migration of contaminant in coastal aquifers. An overheight in the water table as a result of the tidal fluctuation is observed anti this has a significant effect on groundwater discharge to the sea when the landward boundary condition is a constant water level. The effect of beach slope is very significant and simplifying the problem by considering a vertical beach face causes serious errors in predicting the water-table position and the groundwater flux. For media with a high effective capillary fringe, the moisture retained above the water table is important in determining the effects of the tidal fluctuations. Copyright (C) 2001 John Wiley & Sons, Ltd.

Randomized controlled trial of two cigarette quit programmes in coronary care patients after acute myocardial infarction

Background: Tobacco cessation after acute myocardial infarction (AMI) substantially improves outcome but how effective individual programmes are needs to be established. To date, few studies have examined this factor. Aims: To assess the outcome of two smoking cessation programmes after AMI. Methods: One hundred and ninety-eight current smokers admitted to coronary care with an AMI participated in a randomized controlled study comparing two outpatient tobacco interventions, the Stanford Heart Attack Staying Free (SF) programme and a Usual Care (UC) programme. Results: Log-rank analyses revealed that patients in the SF programme were retained longer (P < 0.001) and had higher cotinine validated abstinence rates (P < 0.001) compared with patients in the UC programme. Twelve months after intervention, 39% of the SF programme compared with 2% of the UC programme demonstrated cotinine validated tobacco cessation, representing a significant reduced relapse rate in the SF programme (chi (2), P < 0.001). Conclusions: The SF smoking cessation programme initiated in hospital can significantly reduce smoking rates at 12 months after myocardial infarction. Although superior to the UC quit programme, Australian outcomes were lower than the American programme originators' published outcomes.

Antigenicity and immunogenicity of novel chimeric hepatitis B surface antigen particles with exposed hepatitis C virus epitopes

The small envelope protein of hepatitis B virus (HBsAg-S) can self-assemble into highly organized virus like particles (VLPs) and induce an effective immune response. In this study, a restriction enzyme site was engineered into the cDNA of HBsAg-S at a position corresponding to the exposed site within the hydrophilic a determinant region (amino acid [aa] 127-128) to create a novel HBsAg vaccine vector allowing surface orientation of the inserted sequence. We inserted sequences of various lengths from hypervariable region 1 (HVR1) of the hepatitis C virus (HCV) E2 protein containing immunodominant epitopes and demonstrated secretion of the recombinant HBsAg VLPs from transfected mammalian cells. A number of different recombinant proteins were synthesized, and HBsAg VLPs containing inserts up to 36 aa were secreted with an efficiency similar to that of wild-type HBsAg. The HVR1 region exposed on the particles retained an antigenic structure similar to that recognized immunologically during natural infection. VLPs containing epitopes from either HCV-1a or -1b strains were produced that induced strain-specific antibody responses in immunized mice. Injection of a combination of these VLPs induced antibodies against both HVR1 epitopes that resulted in higher titers than were achieved by vaccination with the individual VLPs, suggesting a synergistic effect. This may lead to the development of recombinant particles which are able to induce a broad anti-HCV immune response against the HCV quasispecies or other quasispecies-like infectious agents.

The effect of heat treatment on the toughness, hardness and microstructure of low carbon white cast irons

The effect of destabilisation and subcritical heat treatment on the impact toughness, hardness, and the amount and mechanical stability of retained austenite in a low carbon white cast iron have been investigated. The experimental results show that the impact energy constantly increases when the destabilisation temperature is raised from 950 degreesC to 1200 degreesC. Although the hardness decreases, the heat-treated hardness is still greater than the as-cast state. After destabilisation treatment at 1130 degreesC, tempering at 200 to 250 degreesC for 3 hours leads to the highest impact toughness, and secondary hardening was observed when tempering over 400 degreesC. The amount of retained austenite increased with the increase in the destabilisation temperature, and the treatment significantly improves the mechanical stability of the retained austenite compared with the as-cast state. Tempering below 400 degreesC does not affect the amount of retained austenite and its mechanical stability. But the amount of retained austenite is dramatically reduced when tempered above 400 degreesC. The relationship between the mechanical properties and the microstructure changes was discussed. (C) 2001 Kluwer Academic Publishers.

Freeform fabrication of aluminum metal-matrix composites

A series of metal-matrix composites were formed by extrusion freeform, fabrication of a sinterable aluminum alloy in combination with silicon carbide particles and whiskers, carbon fibers, alumina particles, and hollow flyash cenospheres. Silicon carbide particles were most successful in that the composites retained high density with up to 20 vol% of reinforcement and the strength approximately doubles over the strength of the metal matrix alone. Comparison with simple models suggests that this unexpectedly high degree of reinforcement can be attributed to the concentration of small silicon carbide particles around the larger metal powder. This fabrication method also allows composites to be formed with hollow spheres that cannot be formed by other powder or melt methods.