bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterisation of Black African entrepreneurship in the UK: a pilot study
Authors: Nwankwo Sonny
Published: March 2005

Purpose

The purpose of this paper is to provide a general characterisation of entrepreneurial orientations of Black Africans in the UK.

Design/methodology/approach

Methodological appropriateness rather than orthodoxy was fundamental in the design of this research. A combination of idiosyncratic and multiplicative sampling strategy was applied in a discovery‐oriented context. Research questions were adapted from the attribution questions frequently used in related studies. In consideration of the exploratory nature of this work, a connected narrative approach was used in presenting the results. Data collection was undertaken in London.

Findings

Observes that many Black Africans embarked on entrepreneurship more to escape ethnic penalties than a strategic response to the structure of environmental opportunities. Thus, this “escapist mindset” has meant that inadequate initial preparations have tended to characterise the small businesses they operate. Recognises that whilst a pattern of market concentration is discernible at the co‐ethnic level (i.e. first entry market), there is little evidence of strategic evolution towards mainstreaming or the attainment of sectoral aggregation either at national or regional level.

Research limitations/implications

Data collection was limited to London‐non‐Black African entrepreneurs were excluded. Therefore, care should be taken in making generalisations from the sample.

Practical implications

Many African‐owned businesses are failure‐prone and in need of strategic interventions in order to secure their growth and sustainability.

Originality/value

Highly valuable with very little research completed to date on this topic.
A MAP for the library portal: through the labyrinth of online information sources
Authors: Myhill Martin
Published: March 2005

Purpose

This paper aims to describe the first year of implementation of the Innovative Interfaces Inc. Millennium Access Plus (MAP) portal at the University of Exeter Library, UK.

Design/methodology/approach

The paper provides a description of the features of MAP and a case study

Findings

In as little as 25 years, online information provision has been transformed. This has largely been uncontrolled, yet the resources now available offer rich returns for the data‐hungry end user. Increasingly, many users require their information immediately and really do not care where it is stored. Such demands, coupled with librarians’ natural tendency to apply order, have led to the development of library portals which aim to solve the problems arising from trying to navigate this labyrinth of information. The MAP portal is one such product. Using the NISO OpenURL standard, MAP offers three main elements – contextual linking via WebBridge, one step “multi” searching using MetaFind and resource authentication through Web Access Management (WAM). Use of this portal at the University of Exeter Library has made a considerable, positive impact on the recent use of online full‐text systems and services and the experiences undoubtedly point to a strong future for such interfaces everywhere.

Research limitations/implications

The paper is limited to experiences at the University of Exeter Library.

Practical implications

The paper will inform the information community on the experiences of this innovative product

Originality/value

This is an original description of a new concept and provides evaluative material.
Parasitic isopods (Gnathia sp.) reduce haematocrit in captive blackeye thicklip (Labridae) on the Great Barrier Reef
Authors: Jones C. M. , Grutter A. S.
Published: March 2005

Captive Hemigymnus melapterus exposed to large numbers of cultured juvenile parasitic isopods (Gnathia sp.) had significantly lower haematocrit (median 27·62% ± 5·83% inter‐quartile range) than uninfected, control fish (median 32·73% ± 4·90%). This study is the first to show that juvenile Gnathia sp. reduce total blood volume in H. melapterus. The low haematocrit in infected fish was most likely due to plasma replacing erythrocytes lost as a result of isopods feeding on fish blood.
Evaluating the effect of clustering when monitoring the abundance of sea lice populations on farmed Atlantic salmon
Authors: Revie C. W. , Gettinby G. , Treasurer J. W. , Wallace C.
Published: March 2005

Using cluster random sampling theory and empirical estimates of the intra‐class correlations for sea lice Lepeophtheirus salmonis abundances, methods on how best to sample Atlantic salmon Salmo salar from cages on farms were derived. Estimates of intra‐class correlations for the abundance of the chalimus and mobile sea lice stages on Atlantic salmon in Scottish farms are given. These correlations were higher for mobile stages than for chalimus, and they had a substantive effect on increasing the number of cages and fish to be sampled for all sea lice stages. An important finding is that it is better to have a procedure that randomly samples a large number of cages using a small number of fish from each. This finding and the cluster random sampling approach have relevance to the monitoring of all marine species being farmed in cages or tanks.
Disruption of lipid rafts causes apoptotic cell death in HaCaT keratinocytes
Authors: Bang Bo , Gniadecki Robert , Gajkowska Barbara
Published: March 2005

Abstract:  Lipid rafts are cholesterol‐enriched microdomains in plasma membranes. The functional activity of many membrane proteins, including death and growth factor receptors, depends on their insertion in lipid rafts. We have previously demonstrated the presence of lipid rafts in keratinocytes and shown that lipid rafts are involved in the control of keratinocyte proliferation and metabolic activity. In this work, we investigated the effect of lipid‐raft disruption on HaCaT keratinocyte survival. Lipid rafts could be disrupted or rearranged with cholesterol‐targeting detergents: methyl‐β‐cyclodextrin and filipin III. Moreover, cholesterol oxidation by a specific oxidase or blocking of cholesterol synthesis by mevastatin had a similar effect on lipid rafts. All cholesterol‐modifying substances caused cell death in a concentration‐dependent manner. More detailed studies on the effects of cyclodextrin revealed apoptotic cell death at concentrations ≥0.5% (w/v). The molecular mechanism of apoptosis precipitated by raft disruption remains unknown but does not seem to be dependent of either membrane permeabilization or cell‐cycle arrest imposed by cholesterol‐modifying compounds.
Long‐term succession in a Danish temperate deciduous forest
Authors: H. W. Bradshaw Richard , Wolf Annett , Friis Møller Peter
Published: March 2005

Forest successional trajectories covering the last 2000 yr from a mixed deciduous forest in Denmark show a gradual shift in dominance from Tilia cordata to Fagus sylvatica and a recent increase in total forest basal area since direct management ceased in 1948. The successions are reconstructed by combining a fifty‐year record of direct tree observations with local pollen diagrams from Draved Forest, Denmark. Five of the seven successions record a heathland phase of Viking Age dating from 830 AD. The anthropogenic influence is considerable throughout the period of study even though Draved contains some of the most pristine forest stands in Denmark. Anthropogenic influence including felling masks the underlying natural dynamics, with the least disturbed sites showing the smallest compositional change. Some effects of former management, such as loss of Tilia cordata dominance, are irreversible. Artificial disturbance, particularly drainage, has accelerated and amplified the shift towards Fagus dominance that would have occurred on a smaller scale and at a slower rate in the absence of human intervention.
Implications of Liebig's law of the minimum for the use of ecological indicators based on abundance
Authors: Hiddink J. G. , Kaiser M. J.
Published: March 2005

Many ecological responses to environmental variables or anthropogenic agents are difficult and expensive to measure. Therefore it is attractive to describe such responses in terms of indicators that are easier to measure. In ecosystem management, indicators can be used to monitor spatial and temporal changes in an environmental feature. The aim of this paper is to show that it is important to take Liebig's law of the minimum into consideration to understand when it is appropriate or inappropriate to use ecological indicators based on abundance. When developing indicators that relate the abundance of an organism to an environmental factor, it is likely that this relationship will be polygonal rather than a simple linear relationship. The upper boundary of the distribution describes how abundance is limited by this factor, while the variation below the upper boundary is explained by situations when factors other than the factor of interest limit abundance. The variation below the upper boundary of the distribution means that the use of indicators to examine spatial patterns in the response of abundance to an environmental factor can be problematic. Thus, while abundance‐based indicators can identify sites that are in a good condition, they are less useful to detect those affected by environmental degradation. In contrast, abundance‐based ecological indicators may enable temporal monitoring of the impact of environmental factors, as it is expected that limiting factors are less variable in time than in space. In conclusion, when multiple factors are limiting, a significant correlation between an indicator and a variable is not enough to validate the status of a factor as an indicator.
Disease and the devil: density‐dependent epidemiological processes explain historical population fluctuations in the Tasmanian devil
Authors: Bradshaw Corey J. A. , Brook Barry W.
Published: March 2005

Australia's last mega‐carnivore marsupial, the Tasmanian devil Sarcophilusharrisii, Dasyuridae is endemic to the island state of Tasmania. The recent appearance and rapid spread of a debilitating and usually lethal, cancer‐like disease has raised concerns regarding the species’ future. We used a demographic matrix modelling approach to evaluate the potential long‐term implications of epidemics on this population. Both adult survival and temporally autocorrelated re‐occurrence of disease were expressed as a function of female abundance. Large fluctuations in abundance resulted when disease outbreaks were conditioned to be density‐dependent; however, this resulted in a low probability of quasi‐extinction due to the dissipation of disease transmission at low densities. Epidemic stochasticity alone in an otherwise deterministic model resulted in major population cycles occurring every 77–146 yr, consistent with historical reports. Although epidemics in this species may not result in extinction directly, the contemporary presence of additional mortality sources during periods of low abundance may increase extinction risk.
Endemic plants of the arid succulent karoo in Namibia: towards hypotheses for their evolution
Authors: Burke Antje
Published: March 2005

This study investigated endemic plants in the Sperrgebiet in the succulent karoo – a global biodiversity hotspot in southern Africa. In order to develop hypotheses regarding the evolution of this endemic flora, the following questions were posed: 1) Are taxonomic patterns similar at different levels of taxonomic order? 2) Are adaptations of Sperrgebiet endemic taxa different from the overall flora? 3) Are adaptations different in related endemic and non‐endemic taxa?

There is an over‐representation of species of Mesembryanthemaceae in the endemic flora, which is in accordance with patterns in the succulent karoo biome overall. The nearly 37% contribution of Mesembryanthemaceae to the endemic flora is, however, remarkably higher than elsewhere in the biome. The over‐representation of this family is not maintained at a higher level of taxonomic order, supporting the notion of recent speciation in this family. Regarding plant functional attributes, major differences between the endemic and non‐endemic flora exist. Compact leaf‐succulents with canopy stored, water‐dispersed seeds, as well as bulbs and shrubby leaf‐succulents predominate the endemic flora. Differences in reproductive (seed storage and dispersal distance) and growth form attributes between the endemic and non‐endemic flora were largely influenced by phylogenetic history. Minutism (plant height <10 cm) was favoured by many endemic plants, but this was not only influenced by phylogenetic factors.

Two hypotheses emerged from these observations: 1) the evolution of minutism is largely driven by external factors in the Sperrgebiet, and 2) external factors and phylogenetic history are likely of equal importance in the development of the Sperrgebiet endemic flora.
B‐domain deleted recombinant factor VIII preparations are bioequivalent to a monoclonal antibody purified plasma‐derived factor VIII concentrate: a randomized, three‐way crossover study
Authors: Kessler C. M. , Gill J. C. , White G. C. , Shapiro A. , Arkin S. , Roth D. A. , Meng X. , Lusher J. M.
Published: March 2005

Summary.  Background:  Deletion of the B‐domain of recombinant blood coagulation factor VIII (BDDrFVIII) increases the manufacturing yield of the product but does not impair in vitro or in vivo functionality. BDDrFVIII (ReFacto®) has been developed with the additional benefit of being formulated without human albumin.

Objective:  The primary objective of this three‐way crossover‐design study was to compare the pharmacokinetic (PK) parameters of two BDDrFVIII formulations (one reconstituted with 5 mL of sterile water, the other reconstituted with 4 mL sodium chloride 0.9% USP) with those of a plasma‐derived, full‐length FVIII preparation (Hemofil® M) in patients with haemophilia A to determine bioequivalence.

Methods:  A series of blood samples were collected over a period of 48 h after i.v. administration of each of the FVIII preparations. Plasma FVIII activity was determined using a validated chromogenic substrate assay. Plasma FVIII activity vs. time curves was characterized for a standard set of PK parameter estimates. Two parameter estimates, the maximum plasma concentration (Cmax) and the area under plasma concentration vs. time curves (AUCs), were used to evaluate bioequivalence. The two preparations were considered bioequivalent if the 90% confidence intervals for the ratio of geometric means for Cmax and AUCs fell within the bioequivalence window of 80% to 125%.

Results/Conclusion:  Results show that each BDDrFVIII formulation is bioequivalent to Hemofil M and the two formulations of BDDrFVIII are bioequivalent to each other.
Changing pattern of care of boys with haemophilia in western European centres
Authors: Chambost H. , Ljung R. ,   on behalf of the Pednet Group
Published: March 2005

Summary.  Haemophilia management is not uniform among countries, even within western Europe, that have close economic, social and cultural relationship. The European Paediatric Network PedNet aims to share experiences in the field of the care of boys with haemophilia. In 1998, a PedNet survey has shown significant disparities in 20 centres from 16 countries, particularly as regards the implementation of prophylaxis regimen. This survey has been updated in 2003 to describe the current status of haemophilia management in 22 centres and the changing pattern of care of boys with severe haemophilia in western Europe. Regular, continuous long‐term prophylaxis is provided in all PedNet centres, more than 50% and 80–100% of boys being treated this way in 20/22 and 15/22 centres respectively. Twenty of the 22 centres (91%) recommend continuous prophylaxis (primary or secondary A) for a new patient. The use of recombinant factor VIII concentrates was already widespread in 1998 and a further expansion of recombinant products has been observed over the last 5 years. Recombinant FVIII is now used exclusively in nine centres and for more than 80% of boys with haemophilia A in nine other centres. The use of recombinant and plasma derived FIX is more balanced: among 18 centres where boys with haemophilia B are treated, 14 use recombinant FIX, and nine administer it to a majority of patients. Other modifications of practice have been stressed in this survey, such as more targeted use of central venous devices in the youngest boys and more extensive characterisation of genetic mutations.
Pressure‐relieving equipment: promoting its correct use amongst nurses via differing modes of educational delivery
Authors: Wedge Claire , Gosney Margot
Published: March 2005

Aims and objectives.  To examine the impact of written and verbal education on bed‐making practices, in an attempt to reduce the prevalence of pressure ulcers.

Background.  The Department of Health has set targets for a 5% reduction per annum in the incidence of pressure ulcers. Electric profiling beds with a visco‐elastic polymer mattress are a new innovation in pressure ulcer prevention; however, mattress efficacy is reduced by tightly tucking sheets around the mattress.

Design.  A prospective randomized pre/post‐test experimental design.

Methods.  Ward managers at a teaching hospital were approached to participate in the study. Two researchers independently examined the tightness of the sheets around the mattresses. Wards were randomized to one of two groups. Groups A and B received written education. In addition, group B received verbal education on alternate days for one week. Beds were re‐examined one month later. One researcher was blinded to the educational delivery received by the wards.

Results.  Twelve wards agreed to participate in the study and 245 beds were examined. Before education, 113 beds (46%) had sheets tucked correctly around the mattresses. Following education, this increased to 215 beds (87.8%) (χ2 = 68.03, P < 0.001). There was no significant difference in the number of correctly made beds between the two different education groups: 100 (87.72%) beds correctly made in group A vs. 115 (87.79%) beds in group B (χ2 = 0, P = 0.987).

Conclusions.  Clear, concise written instruction improved practice but verbal education was not additionally beneficial.

Relevance to clinical practice.  Nurses are receptive to clear, concise written evidence regarding pressure ulcer prevention and incorporate this into clinical practice.
Pressure ulcers: diagnostics and interventions aimed at wound‐related complaints: a review of the literature
Authors: De Laat Erik HEW , Scholte op Reimer Wilma J , Van Achterberg Theo
Published: March 2005

Aims and objectives.  To describe the current scientific evidence in the field of diagnostics and treatment of pain, malodour and exudate from pressure ulcers and to give recommendations for practice, based on these findings.

Background.  Patients with pressure ulcers are confronted with symptoms of chronic wounds and impaired wound healing. Assessment and treatment of these symptoms have received very little attention.

Design.  Systematic literature review.

Methods.  Medline, CINAHL, and Cochrane, were searched for studies on pain, malodour and exudate in patients with pressure ulcers.

Results.  The McGill Pain Questionnaire, the Visual Analogue Scale and the Faces Rating Scale are useful instruments to assess pressure ulcer related pain. Strong evidence was found to support a positive effect of (dia)morphine. Some evidence was found to support a positive effect of benzydamine gel and Eutectic Mixture of Local Anaesthetic‐cream. Wound malodour is subjectively assessed. In a laboratory study, it is proved that activated charcoal is capable of absorbing gas molecules causing malodour. At present, no studies are available on the odour‐absorbing capacity of activated charcoal dressings in pressure ulcer patients. Exudate is a symptom of impaired wound healing. The Pressure Sore Status Tool is a valid and reliable instrument for assessing the wound healing process. There is a possible indication that hydrocolloid positively influences healing time because the absorption of exudates is more effective.

Conclusion.  Little sound research has been performed on wound‐related complaints in patients with pressure ulcers. Nevertheless several recommendations could be made on the present state of the art.

Relevance to clinical pratice.  Regarding pressure ulcer related pain, this review supports the intervention of local pain relieve in patients with pressure ulcers. Regarding pressure ulcer related odour and exudates, this study identifies the gaps in evidence and research.
Scientific evaluation of community‐based Parkinson's disease nurse specialists on patient outcomes and health care costs
Authors: Hurwitz Brian , Jarman Brian , Cook Adrian , Bajekal Madhavi
Published: March 2005

Objective  To determine the effects of community based nurses specialising in Parkinson's disease on health outcomes and healthcare costs.

Design  Two year randomised controlled trial in 438 general practices in nine randomly selected health authority areas of England.

Participants  1859 patients with Parkinson's disease identified by the participating general practices.

Main outcome measures  Survival, stand‐up test, dot in square test, bone fracture, global health question, PDQ‐39, Euroqol, and healthcare costs.

Results  After two years 315 (17.3%) patients had died, although mortality did not differ between those who were attended by nurse specialists and those receiving standard care from their general practitioner (hazard ratio for nurse group v control group 0.91, 95% confidence interval 0.73 to 1.13). No significant differences were found between the two groups for the stand‐up test (odds ratio 1.15, 0.93 to 1.42) and dot in square score (difference −0.7, −3.25 to 1.84). Scores on the global health question were significantly better in patients attended by nurse specialists than in controls (difference −0.23, −0.4 to −0.06), but no difference was observed in the results of the PDQ‐39 or Euroqol questionnaires. Direct costs for patient health care increased by an average of £2658 during the study, although not differentially between groups: the average increase was £266 lower among patients attended by a nurse specialist (−£981 to £449).

Conclusions  Nurse specialists in Parkinson's disease had little effect on the clinical condition of patients, but they did improve their patients’ sense of wellbeing, with no increase in patients’ healthcare costs.
Modernizing UK health services: ‘short‐sharp‐shock’ reform, the NHS subsistence economy, and the spectre of health care famine
Authors: Charlton Bruce G. , Andras Peter
Published: March 2005

Modernization is the trend for societies to grow functionally more complex, efficient and productive. Modernization usually occurs by increased specialization of function (e.g. division of labour, such as the proliferation of specialists  in  medicine),  combined  with  increased  organization  in  order to co‐ordinate the numerous specialized functions (e.g. the increased size of hospitals and specialist teams, including the management of these large groups). There have been many attempts to modernize the National Health Service (NHS) over recent decades, but it seems that none have significantly enhanced either the efficiency or output of the health care system. The reason may be that reforms have been applied as a ‘drip‐drip’ of central regulation, with the consequence that health care has become increasingly dominated by the political system. In contrast, a ‘short‐sharp‐shock’ of radical and rapid modernization seems to be a more successful strategy for reforming social systems – in‐between waves of structural change the system is left to re‐orientate towards its client group. An example was the Flexner‐initiated reform of US medical education which resulted in the closure of nearly half the medical colleges, an immediate enhancement in quality and efficiency of the system and future growth based on best institutional practices. However, short‐sharp‐shock reforms would probably initiate an NHS ‘health care famine’ with acute shortages and a health care crisis, because the NHS constitutes a ‘subsistence economy’ without any significant surplus of health services. The UK health care system must grow to generate a surplus before it can adequately be modernized. Efficient and rapid growth in health services could most easily be generated by stimulating provision outside the NHS, using mainly staff trained abroad and needs‐subsidized ‘item‐of‐service’‐type payment schemes. Once there is a surplus of critically vital health services (e.g. acute and emergency provision), then radical modernization should rapidly improve the health service by a cull of low‐quality and inefficient health care providers.
Comparative analysis of end wall resistivity in xylem conduits
Authors: SPERRY JOHN S. , HACKE UWE G. , WHEELER JAMES K.
Published: March 2005

The hydraulic resistivity (R, pressure gradient/flow rate) through end walls of xylem conduits was estimated in seven species of diverse anatomy and affinity including a vessel‐bearing fern, a tracheid‐bearing gymnosperm, and angiosperms with versus without vessels. Conduit lengths were measured with a silicone injection method which was easier and more accurate than the usual paint injection. The R declined linearly with the removal of end walls as stems were shortened from 10 to 0.3 cm. This relationship gave the minimum R with no end walls present, or the lumen resistivity (RL). This was indistinguishable from the Hagen–Poiseuille value. The maximum R with all end walls present gave RC, the resistivity of end wall and lumen in series. Average end‐wall resistivity (RW) was the difference RC − RL and the ‘wall fraction’ was RW/RC. Wall fraction was approximately constant, averaging 0.54 ± 0.07. This suggests that end wall and lumen resistivities are nearly co‐limiting in vascular plants. Average conduit length was proportional to the diameter squared across species (r2 = 0.94). Together with a constant wall fraction, this was consistent with the end wall resistance (rw, pressure difference/flow rate) being inversely proportional to conduit length. Lower rw in longer conduits is consistent with their having more end wall pits than shorter conduits.
Relationship between total transit time and faecal quality in adult dogs differing in body size
Authors: Hernot D. C. , Biourge V. C. , Martin L. J. , Dumon H. J. , Nguyen P. G.
Published: March 2005

Fed the same diet, large and giant‐breed dogs have higher faecal moisture and increased frequency of soft stools than small ones. This could be the result of physiological differences, such as a different gastrointestinal transit time. In this study, we have correlated mean total transit time (MTT) with body size and faecal consistency in dogs varying in body size. Fifty dogs from 13 different breeds were used, from a Dachshund to a Great Dane. The MTT was determined using coloured plastic beads [Cummings and Wiggins, Gut, Vol. 17 (1976), p. 219], and faecal consistency was scored daily during the study. We confirmed the strong correlation between height at the shoulder (body size) and faecal score (r = 0.76; p < 0.0001). The MTT increased with body size, from 22 h for a Miniature Poodle to 59 h for a Giant Schnauzer. We found significant positive correlations (p < 0.0001) between MTT and body size as well as faecal scores (r = 0.71 and 0.70 respectively). In the present study, we observed an effect of body size on MTT. In our 50 healthy dogs a longer MTT was related to a poorer faecal quality. Previous studies reported no relationship between body size and the upper gastrointestinal transit time in healthy dogs. So, we hypothesized that body size would mainly affect colonic transit time and that a longer colonic residence time would be related to a poorer faecal quality by promoting fermentation activity.
Beet‐vinasse (condensed molasses solubles) as an ingredient in diets for cattle and pigs – nutritive value and limitations
Authors: Stemme K. , Gerdes B. , Harms A. , Kamphues J.
Published: March 2005

Sugar beet vinasse, originating as the condensed molasses residue from yeast production, was fed to bulls and pigs to determine the feed value. It contained, per kg dry matter (DM content 66.8%), 293 g crude protein, 305 g N‐free extract (therefrom 34.4 g total sugar), and 395 g crude ash. The experiment was carried out with three fattening bulls (German Holstein) and four adult pigs (Göttingen Minipig). In bulls, two balance trials lasting 20 days each (10 days adaptation; 10 days collection) were conducted in which subsequently a basal ration without and with vinasse (14% in DM) was fed. In pigs, the experiment consisted of three 12‐day balance trials with the final 5 days as collection period. In the first trial, pigs received a basal diet without vinasse and in the following, a mixed diet with 16 and 43% vinasse (in DM) respectively. Digestibilities of components in vinasse in bulls were: organic matter 73.5%, crude protein 72.6%, and N‐free extract 52.3%. In bulls, no influence on faeces quality could be detected while feeding 14% vinasse in DM. While feeding 16% vinasse in DM to pigs, the digestibility of organic matter amounted to 72.3% (crude protein 71.8%; NfE 74.6%). Feeding higher amounts of vinasse (43% in DM) in the diet of pigs, digestibilities were reduced (organic matter: 61.6%), which might be a result of a reduced retention time of the chyme as a result of an osmotically driven diarrhoea because of unexpectedly high sulphate (136 g/kg DM) content in the vinasse. It is concluded that because of organic matter digestibility >70% for cattle and pigs, the use of vinasse in these species in small proportions is reasonable.
Antifungal Activity of the Essential Oil of Basil (Ocimum basilicum)
Authors: Oxenham S. K. , Svoboda K. P. , Walters D. R.
Published: March 2005

The antifungal and fungicidal effects of two chemotypes of basil (Ocimum basilicum) oil and its major individual components were studied in a series of in vitro and in vivo experiments. Mycelial growth of the plant pathogenic fungus Botrytis fabae was reduced significantly by both the methyl chavicol chemotype oil and the linalol chemotype oil, and the major individual components of the oils all reduced fungal growth, with methyl chavicol, linalol, eugenol and eucalyptol reducing growth significantly. Combining the pure oil components in the same proportions as found in the whole oil led to very similar reductions in fungal growth, suggesting that the antifungal effects of the whole oils were due primarily to the major components. When the fungus was exposed to the oils in liquid culture, growth was reduced by concentrations considerably smaller than those used in the Petri dish studies. Botrytis fabae and the rust fungus Uromyces fabae were also controlled in vivo, with the whole oils of both chemotypes, as well as pure methyl chavicol and linalol, reducing infection of broad bean leaves significantly. Most effective control of fungal infection was achieved if the treatments were applied 3 h postinoculation.
Ordered progress of spermiogenesis to the fertilizable sperm of the medaka fish, Oryzias latipes, in cell culture
Authors: Sasaki Takahiro , Watanabe Akihiko , Takayama‐Watanabe Eriko , Suzuki Makoto , Abe Hiroyuki , Onitake Kazuo
Published: March 2005

Spermiogenesis is significant for producing sperm with equipment for achieving fertilization. Although multiple events occur in a particular order during spermiogenesis, it is unclear how the timing of those events is controlled. In the present study, we found that primary spermatocytes obtained from the spermatogenic testes of Oryzias latipes synchronously differentiated into sperm without contact with somatic cells in culture. Because those sperm can fertilize with mature eggs (Saiki et al., 1997), any events of spermiogenesis that are essential for achieving fertilization are completed in the in vitro spermiogenesis. In the in vitro spermiogenesis, the protamine gene expression was observed in the early period and mitochondrion localization was established in the same period. Those results suggest that both nuclear remodeling and organelle replacement begin in the early period of spermiogenesis. The cytoplasmic lobe was formed after the mitochondrion localization had been established. In most spermatids differentiated in cell culture, a flagellum began to elongate during the early period and continued to elongate up to 3 days. These results revealed the timings of the spermiogenetic events under the intrinsic control of the cultured spermatids toward the formation of fertilizable sperm in O. latipes.
Policy Failure and Petroleum Predation: The Economics of Civil War Debate Viewed ‘From the War-Zone’
Authors: Pearce Jenny
Published: March 2005

The analysis of armed conflict in the post Cold War era has been profoundly influenced by neoclassical economists. Statistical approaches have generated important propositions, but there is a danger when these feed into policy prescriptions. This paper first compares the economics of civil war literature with the social movement literature which has also tried to explain collective action problems. It argues that the latter has a much more sophisticated set of conceptual tools, enriched by empirical study. The paper then uses the case of multipolar militarization in oil-rich Casanare, Colombia, to demonstrate complexity and contingency in civil war trajectories. State policy failure and civil actors can be an important source of explanation alongside the economic agendas of armed actors.
Testing the Focal Point Theory of Legal Compliance: The Effect of Third‐Party Expression in an Experimental Hawk/Dove Game
Authors: McAdams Richard H. , Nadler Janice
Published: March 2005

Economic theories of legal compliance emphasize legal sanctions, whereas psychological and sociological theories stress the perceived legitimacy of law. Without disputing the importance of either mechanism, we test a third way that law affects behavior, an expressive theory that claims law influences behavior by creating a focal point around which individuals coordinate. We investigated how various forms of third‐party “cheap talk” influence the behavior of subjects in a Hawk/Dove or Chicken game. Despite the players’ conflicting interests, we found that messages highlighting an equilibrium tend to produce that outcome. Most striking, this result emerged even when the message was selected by an overtly random, mechanical process. We obtained a similar result when the message was delivered by a third‐party subject; the latter effect was significantly stronger than the former only when the subject speaker was selected by a merit‐based process. These results suggest that, in certain circumstances, law generates compliance not only by sanctions and legitimacy, but also by facilitating coordination around a focal outcome.
An optimal speed for traversing a constant rain
Authors: Stern S. A.
Published: March 2005

Whether it is better to walk or run through a rain shower is a question often posed by adult and child alike. The answer to this question requires careful physical analysis and provides an instructive, even illuminating exercise for high school as well as undergraduate introductory physics classes. In this paper, we will derive a rule for the optimal travel speed which minimizes the number of rainstrikes on a given surface element over a given course. We shall also investigate the speed versus intensity relationship. Methods of extending these results to include rainfalls with horizontal velocity relative to the travel path and for surfaces of arbitrary geometry are presented in Sec. VI.
A spherical viewing screen for diffraction patterns
Authors: Ayers R. Dean
Published: March 2005

Fraunhofer diffraction from a planar diffracting object is explained in terms of spatial Fourier transforms and the Ewald sphere construction from solid-state physics. It is found that the most meaningful view of such a diffraction pattern is obtained by letting it fall on a spherical screen centered upon the diffracting object and then observing the pattern from a distance along the normal to the plane. This visual projection yields a circular portion of the two-dimensional spatial transform of the diffracting object without any geometrical distortion. A classroom demonstration using a laser and crossed gratings of good quality illustrates clearly the superiority of this viewing technique over the standard procedure of simply allowing the pattern to fall directly on a flat screen.
In Vino Veritas: A study of wineglass acoustics
Authors: French A. P.
Published: March 2005

This paper describes an investigation of the natural resonant frequencies of vessels such as wineglasses. Measurements on a number of glasses are interpreted with the help of theoretical predictions based on the analysis of vibrating systems by means of the energy method. Results and analysis are given for empty glasses and for glasses containing different amounts of liquid. Evidence for vibrational modes above the lowest is presented.
The photoelectric determination of h/e: A new approach to an old problem
Authors: Knudsen Arthur W.
Published: March 2005

A method is described for the photoelectric determination of h/e, based on Fowler’s classic theory of the frequency-dependent photoelectric yield. In this method, the geometrical arrangement of the electrodes in the h/e phototube is found to be of fundamental importance, and great care was taken to ensure that plane-parallel geometry was maintained. This method, which provides a value of h/e to within (2)/(3) % of the accepted value, is objective and accurate and is considered to be a very suitable experiment for an advanced undergraduate physics laboratory.
Zeeman effect in heavy muonic atoms
Authors: Silverman Mark P.
Published: March 2005

The interaction of a heavy muonic atom with an external magetic field is modeled by a quantized oscillator with spin-orbit coupling. Perturbation solutions are obtained which cover the full range of weak- , intermediate- , strong- , and ultrastrong-field cases depending on the relative values of the parameters characterizing the Coulombic, spin-orbit, and magnetic interactions. The effect of symmetry on the choice of a complete set of commuting observables with which to define a basis is discussed; the strong-field diamagnetic interaction is used as a example to demonstrate that the determination of level separations and degeneracies is independent of the choice of basis. The model is applied to the heavy muonic atom 238U to ascertain whether the splitting of degenerate states by an external magnetic field is experimentally observable.
Constructing objective tests
Authors: Aubrecht Gordon J. , Aubrecht Judith D.
Published: March 2005

True–false or multiple-choice tests can be useful instruments for evaluating student progress. We examine strategies for planning objective tests which serve to test the material covered in science (physics) courses. We also examine strategies for writing questions for tests within a test blueprint. The statistical basis for judging the quality of test items are discussed. Reliability, difficulty, and discrimination indices are defined and examples presented. Our recommendation are rather easily put into practice.
A theorem for physicists in the theory of random variables
Authors: Gillespie Daniel T.
Published: March 2005

A theorem is presented which tells how to calculate the joint probability distribution of m random variables that have been defined as functional transformations of n given random variables (m, n≥1). Although the theorem involves Dirac delta functions and therefore has a rather formal appearance, it turns out to be surprisingly useful. It is used here to develop a number of important results in random variable theory, including: the central limit theorem, the density functions of some common probability distributions (lognormal, chi-square, and Student’s-t), the imposition of constraints on random variables, some sampling properties of the normal distribution, and the chi-square goodness-of-fit test. Special attention is given to aspects of these topics that find fruitful application in physics. A broad conclusion seems to be that the theorem presented here provides a systematic way of obtaining many results in random variable theory which, although quite useful in physics, are normally found derived only in moderately advanced mathematics textbooks.
Physicist’s version of traveling salesman problem: statistical analysis
Authors: Armour Rollin S. , Wheeler John A.
Published: March 2005

We report a statistical calculation of the average distance covered by the traveling salesman, per customer visited, in its dependence upon the width of the ‘‘swaths’’ of landscape covered. We find a ‘‘practical person’s minimum of (0.921) (density of points)−1/2 for a swath width of (1.732) (density of points)−1/2. The point of greatest physical interest is the foliation induced in the random pattern of cities to be visited by the ‘‘regulating principle’’ of minimum distance.
A tidal force pendulum
Authors: Gro/n O/.
Published: March 2005

A tidal force pendulum is presented. Its period is calculated in three different ways: (a) by means of the spin equation, (b) using the Lagrangian formalism, and (c) by means of the equation for geodesic deviation. The period of the pendulum is independent of its length. It depends only upon the curvature of space-time at the position of the pendulum.
A new parametrization of the rotation matrix
Authors: Piña E.
Published: March 2005

A new parametrization of the rotation matrix is presented assuming it is known that this matrix transforms a particular vector into another vector. The matrix is expressed as a function of these vectors and of an angle which measures the deviation from the shortest possible rotation. Some applications of this representation to dynamics are also explained.
Double-exposure speckle photography for the measurement of small displacements
Authors: Wu E. S. , Geohegan D. B.
Published: March 2005

The method of double-exposure speckle photography (DESP) has been illustrated in experiments to determine the small displacements of a solid object. The object was illuminated by laser light and the speckle pattern was photographed on a stationary photographic film twice, once before and once after the object was displaced. The doubly exposed film, after being photographically processed, was illuminated by laser light to produce equally spaced Young’s interference fringes on the Fraunhofer diffraction plane. From the spacing and the orientation of these fringes, both the magnitude and the direction of the displacement were determined. We have used the DESP method to measure the small length change of a cadmium tube due to thermal expansion and determined the linear thermal expansion coefficient of cadmium.
Feynman’s disk paradox
Authors: Lombardi Gabriel G.
Published: March 2005

A paradox involving the apparent violation of angular momentum conservation is discussed. Electromagnetic induction is used to impart angular momentum to a disk of charges. The paradox is resolved by finding the origin of the angular momentum.
Experiments with loaded dice
Authors: Levin Eugene M.
Published: March 2005

Plastic cubes (dice) were ‘‘loaded’’ for asymmetric insertion of brass cylinders, thereby displacing the mass center from the geometric center of each cube. The statistics of seven differently ‘‘loaded’’ dice have been studied experimentally, and the results analyzed in terms of a Boltzmann-like model involving gravitational energy differences among the various orientations. ‘‘Loaded dice’’ may provide interesting and easily visualized systems for the introduction of concepts such as activation energy, degeneracy, partition function, and elementary group theory.
Integral equation methods in electrostatics
Authors: Martínez G. , Sancho M.
Published: March 2005

An integral equation approach to the electrostatic problem applied to charged conductors and homogeneous dielectric media is presented for instructional purposes. Several schemes of an approximated solution are obtained by replacing the integral equations with discrete sets of algebraic equations. We study some examples and discuss the advantages of these methods compared with the finite-difference techniques.
Quantum solutions of the damped harmonic oscillator
Authors: Milburn G. J. , Walls D. F.
Published: March 2005

Solutions to the Fokker–Planck equation for a damped harmonic oscillator corresponding to uniquely quantum-mechanical initial states with no classical correspondence are given.
Energy forms or energy carriers?
Authors: Falk G. , Herrmann F. , Schmid G. Bruno
Published: March 2005

It is customary to say that energy exists in different forms which are transformed or converted into one another during physical processes. However, a careful analysis shows that thinking in and speaking of energy forms is inappropriate and conceptually even misleading. Since most textbooks use the term ‘‘energy form’’ without spelling out a clear procedure by which different ‘‘forms’’ of energy can be categorized, rigorous criteria for categorizing flowing and stored energy are discussed in this paper. These criteria show that the term ‘‘energy form’’ for the respective categories is unsatisfactory because it easily leads to the misinterpretation that there are different kinds of energy, rather than emphasizing the simpler and physically more correct picture of energy as an unalterable substance. Taking into account the well-known but little recognized natural law that energy always flows simultaneously with at least one other physical quantity, the concept of energy carrier is introduced. This concept provides a clear picture of how energy is transported, exchanged, and stored. This picture is scientifically accurate, yet simple and easy to present even at an elementary level.
Alternative approach to the concepts of special relativity
Authors: Kannenberg L.
Published: March 2005

Some subtleties in the concept of simultaneity are avoided with a presentation of relativity which emphasizes the importance of the inertial frames as a privileged set for reconciling transit times of signals traversing closed curves in opposite senses.
Hybrid expansion and improved convergence: An example
Authors: Dykla John J.
Published: March 2005

Approximate solutions of algebraic systems using a hybrid of transcendental functions and series expansions are discussed. Convergence comparison of the results of this approach is made with those of the usual series expansion solution for the effect of a linear resisting medium on projectile range in Newtonian dynamics.
Elementary theory of perihelion precession
Authors: Davies B.
Published: March 2005

A simple method is presented for calculating the effect of a perturbing central force on an elliptic Keplerian orbit. It has the advantage of being direct, and along the lines of the conventional canonical perturbation theory of celestial mechanics. It is applied to the problem of Mercury’s perihelion precession using for the averaged radial force an expression derived by Price and Rush [Am. J. Phys. 47, 531 (1979)].
Magnetic behavior of superconductors: An experiment for the advanced laboratory
Authors: Behroozi F.
Published: March 2005

Superconductivity holds a special appeal to undergraduates and can provide fascinating and instructive experiments in the advanced laboratory. Here we discuss a convenient method to obtain the magnetization curves of superconductors and use the method to study the diamagnetic behavior of tin and vanadium as representatives of the two types of superconductors.
Alternative derivation of the electric dipole radiation fields
Authors: Souza J. A.
Published: March 2005

We propose an alterative derivation of the fields of an oscillating electric dipole, which makes explicit reference to the dipole from the beginning, is mathematically simple, and involves no approximations.
Experimental analysis of I–V characteristics of solar cells
Authors: Mialhe P. , Charette J.
Published: March 2005

This paper describes a simple experiment that can be performed by undergraduate students to derive the values of solar cell parameters from the plot of the output load current versus the voltage at the terminals of the cell.