bluuebunny/crossref_metadata_2025 huggingface dataset:
Conservation of Pathogenic TCR Homology across Class II Restrictions in Anti-Ribonucleoprotein Autoimmunity: Extended Efficacy of T Cell Vaccine Therapy
Authors: Zang YunJuan , Martinez Laisel , Fernandez Irina , Pignac-Kobinger Judith , Greidinger Eric L.
Published: March 2014

T cells have been shown to mediate aspects of anti-ribonucleoprotein (RNP) autoimmunity, and are a potential target of therapy in lupus and related diseases. In this study, we assessed the relevance of a conserved class of anti-RNP T cells to autoimmune disease expression and therapy. Our data show that anti-RNP T cell selection induced a limited set of homologous CDR3 motifs at high frequency. Homologous CDR3 motifs have been reported in other autoimmune diseases. Vaccination with irradiated anti-RNP (but not anti–tetanus toxoid) CD4+ cells induced remission of anti-RNP–associated nephritis in ≥80% of treated mice, even with donor/recipient MHC class II mismatch, and in both induced and spontaneous autoimmunity. Vaccine responder sera inhibited anti-70k T cell proliferation and bound hybridomas expressing the conserved CDR3 motifs. Our data indicate that a limited set of TCR CDR3 motifs may be important for the pathogenesis of anti-RNP lupus and other autoimmune diseases. The ability to target a consistent set of pathogenic T cells between individuals and across class II restrictions may allow for the more practical development of a standardized anti-RNP T cell vaccine preparation useful for multiple patients.
Regulatory CD4+ T Cells Promote B Cell Anergy in Murine Lupus
Authors: Liu Yaoyang , Liu Aijing , Iikuni Noriko , Xu Huji , Shi Fu-Dong , La Cava Antonio
Published: March 2014

To prevent autoimmunity, anergy of autoreactive B cells needs to be maintained, together with the suppression of hyperactive B cells. We previously reported that CD4+CD25+Foxp3+ regulatory T cells (Tregs) can directly suppress autoantibody-producing autoreactive B cells in systemic lupus erythematosus. In this article, we show that Tregs can also reduce the production of autoantibodies in (NZB × NZW)F1 mouse lupus B cells by promoting B cell anergy, both in vitro and in vivo. This phenomenon associated with a reduction in Ca2+ flux in B cells, and CTLA-4 blockade inhibited the effects of Tregs on anergic lupus B cells. These findings identify a new mechanism by which Tregs can control production of autoantibodies in lupus B cells and, more generally, B cell activity in physiopathological conditions.
A Case of Life-Threatening Obstetrical Hemorrhage Secondary to Placental Abruption at 17 Weeks of Gestation
Authors: Kinoshita Toshihiko , Takeshita Naoki , Takashima Akiko , Yasuda Yutaka , Ishida Hiroaki , Manrai Megumi
Published: March 2014

A 40-year old woman, gravida 4, para 4, presented with sudden lower abdominal pain and severe vaginal bleeding at 17 weeks of gestation. Clinical symptoms and ultrasonographic finding revealed placental abruption. The volume of bleeding was heavy and led to disseminated intravascular coagulation and hypovolemic shock. We performed blood transfusion and therapy to treat the critical condition. However, the mother’s condition continued to worsen. Therefore, we performed a hysterotomy and aborted the pregnancy to save the mother. Since heavy bleeding caused by placental abruption leading to a life-threatening condition for a mother before the 20 weeks of gestation is very rare, the present case is an important case study.
Posterior Reversible Encephalopathy Syndrome Mimicking Cerebral Metastasis: Contraindication for Biopsy
Authors: Morina Dukagjin , Ntoulias Georgios , Maslehaty Homajoun , Scholz Martin , Petridis Athanasios K.
Published: March 2014

The posterior reversible encephalopathy syndrome (PRES) is a well described entity of white matter pathology. PRES is triggered by numerous different factors such as acute elevated arterial hypertension, immunosupressive therapy, chemotherapy, etc. The case of a 67-year old woman is presented. The patient was treated for breast cancer 10 months ago and because of acute disorientation a magnetic resonance imaging (MRI) was performed. In the MRI biparieto-occipital hyperintense lesions were seen. Brain metastases were suspected. After chemothe - rapy and hypertonia and the typical appearance of the lesions in the MRI, PRES was also suspected. Before initializing the surgery for an open biopsy a follow-up MRI had been performed (2 weeks after initial MRI). In follow-up MRI the lesions disappeared completely proving the diagnosis of PRES. PRES can be misdiagnosed as a tumour and surgery could be mistakenly performed. It’s important to keep the differential diagnosis of PRES in mind when radiologic features of the syndrome are present.
Strength Asymmetry of the Shoulders in Elite Volleyball Players
Authors: Hadzic Vedran , Sattler Tine , Veselko Matjaž , Markovic Goran , Dervisevic Edvin
Published: March 2014

Context:

Volleyball players are reported to have shoulder strength imbalances. Previous authors have primarily investigated small samples of male players at a single skill level, without considering playing position, and with inconsistent findings.

Objective:

To evaluate shoulder strength asymmetry and a history of shoulder injury in a large sample of professional volleyball players of both sexes across different playing positions and skill levels.

Design:

Descriptive laboratory study.

Patients or Other Participants:

A sample of 183 volleyball players (99 men, 84 women).

Main Outcome Measure(s):

We assessed shoulder internal-rotator and external-rotator concentric strength at 60°/s using an isokinetic dynamometer and dominant-nondominant differences in shoulder strength and strength ratios using repeated-measures analyses of variance. Peak torque was normalized for body mass and external-rotation/internal-rotation concentric strength.

Results:

Internal-rotation strength was asymmetric in favor of the dominant side in both sexes, regardless of previous shoulder injury status. Male volleyball players had a lower shoulder strength ratio on the dominant side, regardless of previous shoulder injury status. However, this finding was valid only when hand dominance was taken into account. Female volleyball players playing at a higher level (ie, first versus second division) were 3.43 times more likely to have an abnormal strength ratio. Playing position was not associated with an abnormal shoulder strength ratio or strength asymmetry.

Conclusions:

In male volleyball players, the external-rotation/internal-rotation strength ratio of the dominant shoulder was lower, regardless of playing position, skill level, or a previous shoulder injury. In female players, the ratio was less only in those at a higher skill level. Although speculative, these findings generally suggest that female volleyball players could have a lower risk of developing shoulder-related problems than male volleyball players. Isokinetic shoulder testing may reveal important information about the possible risk factors for shoulder injuries, so we recommend including it in the functional screening of volleyball players.
Postinjury Anxiety and Social Support Among Collegiate Athletes: A Comparison Between Orthopaedic Injuries and Concussions
Authors: Covassin Tracey , Crutcher Bryan , Bleecker Alisha , Heiden Erin O. , Dailey Alexander , Yang Jingzhen
Published: March 2014

Context:

When an athlete is injured, the primary focus of the sports medicine team is to treat the physical effects of the injury. However, many injured athletes experience negative psychological responses, including anxiety, regarding their injury.

Objective:

To compare the anxiety and social support of athletes with concussions and a matched group of athletes with orthopaedic injuries.

Design:

Cross-sectional study.

Setting:

Athletic training room.

Patients or Other Participants:

A total of 525 injuries among athletes from 2 Big Ten universities were observed. Of these, 63 concussion injuries were matched with 63 orthopaedic injuries for the athlete's sex, sport, and time loss due to injury.

Main Outcome Measure(s):

Clinical measures included the State-Trait Anxiety Inventory (which measures both state and trait anxiety) and the modified 6-item Social Support Questionnaire.

Results:

The group with concussions relied on their family for social support 89% of the time, followed by friends (78%), teammates (65%), athletic trainers (48%), coaches (47%), and physicians (35%). The group with orthopaedic injuries relied on their family for social support 87% of the time, followed by friends (84%), teammates (65%), athletic trainers (57%), coaches (51%), and physicians (36%). We found no differences for the State-Trait Anxiety Inventory (t = −1.38, P = .193) between the concussed and orthopaedic-injury groups. Social Support Questionnaire scores were significant predictors for postinjury state anxiety. Specifically, increased scores were associated with decreased postinjury state anxiety (β = −4.21, P = .0001).

Conclusions:

Both the concussed athletes and those with orthopaedic injuries experienced similar state and trait anxiety and relied on similar sources of social support postinjury. However, athletes with orthopaedic injuries reported greater satisfaction with support from all sources compared with concussed athletes. In contrast, concussed athletes showed more significant predictor models of social support on state anxiety at return to play.
Practice Effects Associated With Repeated Assessment of a Clinical Test of Reaction Time
Authors: Del Rossi Gianluca , Malaguti Alfonso , Del Rossi Samanta
Published: March 2014

Context:

Researchers have confirmed that the ruler-drop test could be included as part of a multifaceted concussion-assessment battery and potentially as a way to track recovery from head injury. However, it is unclear if this clinical test of reaction time would be characterized by inconsistent performance because of practice effects.

Objective:

To determine if the ruler-drop test is susceptible to practice effects after serial administration.

Design:

Descriptive laboratory study.

Setting:

Sports medicine research laboratory.

Patients or Other Participants:

Forty-three persons (age = 21.8 ± 2.6 years).

Intervention(s):

Ten sessions were completed over 5 weeks. Participants completed 10 trials of the ruler-drop test during each session.

Main Outcome Measure(s):

The mean reaction times calculated for all participants from each test session were analyzed to determine if there was any meaningful change (ie, improvement) in reaction time over the course of the investigation.

Results:

Simple reaction time improved (ie, decreased) after repeated administration of the ruler-drop test, and the most pronounced improvement occurred between the first 2 test sessions. Between the first and second test sessions, reaction time decreased by almost 7 milliseconds, and there was an overall improvement of almost 13 milliseconds between the first and tenth sessions. Although the pairwise comparisons between the first and second and the first and third sessions were not significant, the change in mean reaction time between the first session and most of the other sessions was significant. We noted no differences when successive sessions were compared.

Conclusions:

To prevent practice-related improvements in reaction time, practitioners should allow at least 1 practice session before recording baseline results on the ruler-drop test.
Lower and Middle Pennsylvanian conodonts from the Canadian Arctic Archipelago
Authors: Bender K P
Published: March 2014

Eleven stratigraphic sections of the Otto Fiord Formation and lower parts of the Hare Fiord and Nansen Formations were sampled on northern Ellesmere Island. Samples from these sections yielded 7789 conodont specimens which are assignable to 27 form-species (19
platform and 8 ramiform elements) and 3 multielement species. An informal zonation based on four distinct faunas is established. In ascending order, the faunal units are: Adetognathus lautus, Idiognathoides lateralis-I. noduliferus, Idiognathoides sinuatus, and Idiognathoides opimus. Correlation of
these units with Upper Carboniferous zonations established elsewhere is made difficult because some species appear to have a slightly different stratigraphic range in Arctic regions than they do elsewhere.
Quaternary geology of central Melville Island, Northwest Territories
Authors: Hodgson D A ,   Geological Survey of Canada, Vincent J -S , Fyles J G
Published: March 2014

Moderately to completely weathered Devonian clastic rocks caver much of central Melville Island, including Dundas Peninsula. The principal Quaternary deposits are till and ice contact gravels, which occur in central and southeastern Dundas Peninsula. Deltaic and
marine nearshore and beach sediments are scattered along lowland coasts. Continental ice sheets, dispersing from the south, reached their maximum limits on central Melville Island during at least three episodes; only the age of the last advance has been determined. The oldest and most extensive
glaciation recognized covered at least southern Dundas Peninsula up to 300 m a.s.l. and deposited Dundas Till plus a major belt of ice contact deposits. During a subsequent glaciation, ice from Parry Channel overlapped the south-central coast of Dundas Peninsula up to 100 m a.s.l. and deposited
Bolduc Till. This deposition may have occurred at the same time that ice entered Liddon Gulf from the south, depositing Liddon Till to 100 m a.s.l. on the outer gulf coast. At 11 700 ± 100 BP, all coasts were rising after crustal depression by ice assumed to have occupied Parry Channel and
possibly covered the central Queen Elizabeth Islands. Maximum emergence on the south coast is at least 90 m; on all coasts farther north a prominent (and highest) water plane is recorded at about 55 m a.s.l. Subsequent to this initial emergence, ice from Parry Channel readvanced over, and retreated
from, the south coast of Dundas Peninsula probably between 10 340 ± 150 and 9670 ± 150 BP, depositing Winter Harbour Till up to 120 m a.s.l. Because shoreline emergence was not significantly interrupted by this readvance, it is concluded that off shore this ice sheet was probably floating.
Local ice caps existed at undetermined times on the uplands of Melville Island, north of Dundas Peninsula.
Current Research, Part E
Authors:   Geological Survey of Canada
Published: March 2014

About 450 bulk stream silt samples were collected from 1985 to 1987 for a resource assessment of proposed extensions of the Nahanni National Park Reserve. For the study reported here, 211 of these samples were passed on a water1ed concentrating table to
recuperate heavy mineral concentrates (HM Cs) for neutron activation analysis. Results were compared with previous analyses of standard stream silts and HMCs prepared from sandy gravels taken at the same sites. The HMCs from silts confirmed a gold anomaly at Wretched Creek which had been identified
by the HMCs from sandy gravels but missed by standard silt samples. The HMCs from silts also identified 6 new placer gold anomalies: Jackfish River, Windy Creek in Liard Range, a small tributary to Nahanni River at the south end of Nahanni Karst, and 3 tributaries in Ram Plateau. Base metal values
from the two different sets of HM Cs parallel those of the standard silt samples and spring waters.
Le GeoHashTree, une structure de données multirésolution pour la gestion des nuages de points
Authors: Sabo N , Beaulieu A , Bélanger D , Belzile Y , Piché B
Published: March 2014

Over a number of years, LiDAR has become one of the major elevation data acquisition technologies. However, the management of LiDAR data is extremely complex due to the phenomenal amount of data generated by the technology. To facilitate LiDAR data management,
this article proposes a GeoHashTree, which is a multi-resolution data structure for managing different types of point clouds. GeoHashTree is a hierarchical structure which can present irregular data with various levels of abstraction. In addition to facilitating the management of point clouds, the
structure minimizes data storage space considerably, while also facilitating data access and handling. In this article we present this structure. In addition to introducing the GeoHashTree, the article also describes a prototype based on the structure.
Koolstofisotoopsamestelling van Plantproteïene
Authors: Vogel J. C.
Published: March 2014

Die klein verskuiwings wat in die verhouding van die stabiele (nie-radioaktiewe) koolstofisotope wat in die natuur gevind word, kan inligting verskaf oor die fisiese en chemiese prosesse waarby die isotoopmolekule betrokke is.
Moral and ethical dilemmas relating to hitman genetics
Authors: Gericke G. S.
Published: March 2014

Moral and ethical dilemmas relating to therapeutic abortion for genetic indications and to modification of human genetic material are discussed. Due to an increasing gap between advances in clinical genetics and every day clinical practice, it is feared that not all practitioners are able to participate in the discussion of these sensitive issues.
Plantolie as dieselbrandstof: (i) Stabiliteitstoetse en spesifikasies vir verskillende grade plantolies
Authors: Du Plessis L. M.
Published: March 2014

Aanvanklike korttermyn proefnemings met plantolie as dieselbrandstof deur die Nasionale Meganiese Navorsingsinstituut (WNNR) is deur langtermynstudies by die Afdeling Landbouingenieurswese (Departement Landbou) opgevolg. Die Nasionale Voedselnavorsingsinstituut is genader om hulp t.o.v. die chemiese samestelling en stabiliteitseienskappe van die plantolies te verleen.
The thermal environment required by patients and nursing staff in general wards
Authors: Wentzel J. D.
Published: March 2014

Often it is accepted and believed that all areas in hospitals should be air-conditioned. In view of the current high cost of installing and operating air-conditioning units, an objective study of the real needs in this regard was proposed. Whereas the need for air-conditioning in operating theatres, intensive care units and other rather specialised areas is accepted in principle, it is an open question whether all rooms need such treatment. The question could be answered only after a thorough investigation into the actual thermal environmental requirements of patients and nursing staff in general wards. Some 1 300 patients and 60 nurses were interviewed in six local hospitals and their subjective reactions to the various thermal environments to which they were exposed were analysed in terms of three different comfort indices. Air temperature was found to be a good comfort index when the humidity is relatively low.
Satellite observation of ocean colour off the South African West Coast
Authors: Walters N. M.
Published: March 2014

The Coastal Zone Colour Scanner (CZCS) on board of the Nimbus-7 satellite measures ocean radiance at different wavelengths in order to map phytoplankton pigment distributions and sediment distributions as well as temperature patterns in the coastal zone. A series of optical and biological measurements were carried out along the Cape West Coast to determine the relationship between ocean colour and phytoplankton pigment concentration. This paper presents a brief description of the algorithm used to determine phytoplankton pigment from satellite data, which is then compared with sea data collected during February 1979 off the West Coast. Results indicate that the pigments can be determined with a accuracy of factor 2, which compares favourably with the results obtained by other investigators. It appears that this new method of pigment determination on a global scale will provide an important tool in the study of upwelling processes and in a more efficient management of fish resources.
Prostaglandins and thrombosis formation
Authors: Verstraete M.
Published: March 2014

As a group, postaglandins (PG) are composed of a pentagonal carbonring with oxygensubstitutes and two long parallel carbonchains. According to the precise composition of the pentane ring, they are called by the letters A until I (for instance: prostaglandin F), the subscript numeral points to the number of double bonds in the side chain (for instance: F1) and a Grecian letter shows there exist isomers (for instance: Prostaglandin F1), All prostaglandins proceed from essential fatty acids with 20 carbon atoms.
A procedure for the calculation of flow through axisymmetric ducts
Authors: Heyns P. S.
Published: March 2014

A procedure for the calculation of flow through axisymmetric ducts as are typically found in turbomachines, is presented. The procedure is based on a streamline curvature method with the governing equations formulated along quasi-orthogonals in the flow field. This formulation allows the procedure to be used for segments of a duct wherein the flow direction is predominantly radial. It is assumed that the flow on specific stream surfaces is isentropic, but normal entropy gradients may exist because of processes which took place upstream of the duct.
Pollutant concentrations predicted by a steady state Gaussian plume model
Authors: Fourie O. L. , Venter J. C. , Vleggaar C. M.
Published: March 2014

This article describes a computer program that estimates air pollutant concentrations in the vicinity of an elevated point source. The program is intended to be used in screening applications, i.e. applications where it is necessary to make a rapid analysis of a number of scenarios in order to identify situations where there may be cause for concern. The program uses a steady state Gaussian plume model and is based, with a number of exceptions, on Turner’s workbook. It is capable of calculating concentrations in cases of straightforward advection-diffusion, i.e. with a very high mixing layer, as well as in cases of fumigation or multiple reflections. The atmospheric stability classification is done with a scheme which applies to Highveld conditions. Both plume rise and plume spread are calculated using formulas established by Briggs. The effect of topography on the plume trajectory is taken into account in a rudimentary manner.
Semi-projective modules
Authors: Döman D.
Published: March 2014

It is well-known that the submodules of a projective module need not be projective. In this article we investigate a certain projectivity which is preserved under the taking of submodules. This property is used to characterize hereditary rings and QF rings.
A review of the preparation methods of heterogenized catalysts
Authors: Du Plessis J. A. K. , Pienaar J. J.
Published: March 2014

Heterogenized catalytic systems consist of compounds which act as catalysts and carriers onto which these compounds are attached. A review of the methods to prepare heterogenized catalysts is discussed under the headings: a. organic carriers which contain organic, halide, phosphinic or amine groups onto which the catalyst compound is attached; and b. inorganic carriers.
Different approximation for regionalized variables
Authors: Van Tonder G. J. , Botha J. F.
Published: March 2014

A regionalized variable is any numerical function with a spatial distribution which varies from one place to another with apparent continuity. Least squares, distance weighted averaging and kriging can be used to approximate these regionalized variables, this paper presents an overview of these methods and shows how Chebychev polynomials are used in conjunction with simple kriging for the approximation of regionalized variables.
Statistical analysis based on quaternion normal random variables
Authors: Rautenbach H. M. , Roux J. J. J.
Published: March 2014

The quaternion normal distribution is derived and a number of characteristics are highlighted. The maximum likelihood estimation procedure in the quaternion case is examined and the conclusion is reached that the estimation procedure is simplified if the unknown parameters of the associated real probability density function are estimated. The quaternion estimator is then obtained by regarding these estimators as the components of the quaternion estimator. By means of a example attention is given to a test criterium which can be used in the quaternion model.
Nuclear energy: today and tomorrow in the RSA
Authors: Schumann W. A.
Published: March 2014

The energy content of relevant materials and world energy resources are briefly discussed. A short review is given of fundamental aspects of uranium enrichment and the disposal of radio-active material as part of the conventional nuclear fuel cycle. Alternative energy production systems for the RSA are suggested. These are based on the spectrum of choices presented by the nuclear energy continuum of nuclear fission, fusion and spallation particle accelerator systems.
Electricity supply in South Africa
Authors: De Villiers J. W. L.
Published: March 2014

ESCOM, at present providing for some 95% of the electricity demand, has grown from a relatively small undertaking with a total installed capacity of less than 30 MW(e) in 1922 and a capital expenditure of R15 million during the period 1923 -1930, to a gigantic undertaking with a fixed-asset value of nearly R16 billion in 1984, a staff complement of more than 60 000 and an income of over R3 billion p.a. With an estimated capital-expansion programme of between 4 and 5 billion rand p.a., ESCOM is the largest single borrower on the local capital market and it exercises a strong influence on the economy.
The unique requirements of primary health care in Southern Africa
Authors: Knobel D. P.
Published: March 2014

The critical need for primary health care in Southern Africa with special reference to the demands of the heterogenous population is measured against the background of the declaration of Alma Ata at the WHO/UNICEF conference in 1978. In particular the provision of primary health care to the Third World communities of the RSA as an essential part of the security power base of the State is underlined and it is analised in terms of how shortcomings in this service can be exploited in a subversive revolutionary onslaught.
An evaluation of the microhistological technique in the determination of food preferences of game
Authors: Botha R. , Kok P. D. F. , Ellis R. P.
Published: March 2014

During the past ten years much research on the identification of especially grass species in the stomach content and faeces of herbivores has been undertaken. This has contributed significantly towards the knowledge of which plant species are being eaten by animals. In spite of these successful investigations, many problems are still experienced. This caused some research workers to reject the method completely, while others are of the opinion that the method has merits. A survey of the literature as well as research indicate that there are especially three aspects that may influence the results, but that they are ignored by most authors. These include the variation in the epidermis of the grass species, the digestibility of the grass species and the methods used in the investigations.
The importance of water as a basic need for economic development in Region 23
Authors: Van Wyk L. A. , Viviers W.
Published: March 2014

The economic developmental potential of region 23 is to be found mainly in the field of the primary sector. Future development in the agricultural sector is dependent upon large volumes of water. To realise the developmental potential of Region 23 is essential that a reconciliation be affected between the demand for water by the various consumers, and the availability of groundwater and surface water resources. From the balance sheets compiled for the years 1970, 1980 and 2000, it appears that Region 23 already experienced water shortages in 1970. Should supplementation from local sources not take place, more water will have to be withdrawn from the Vaal River, which can present serious problems. As a result of water shortages in Region 23 priorities have to be determined according to how much water will be allocated to various consumers with due regard being given to the strategic value of certain products. Economic development in Region 23 demands large volumes of water as a basic need, and measures to create a reconciliation between supply and demand should receive urgent attention.
The anthropic principle
Authors: Boeyens J. C. A.
Published: March 2014

The fundamental constants of nature are tuned so delicately to support biological life and the coincidence is statistically so improbable that accidental origin of the known universe can be ruled out with certainty. The anthropic principle explains this contingency. The relationship with many-world holistic models is discussed.
The World Ocean Circulation Experiment (WOCE)
Authors: Lutjeharms J. R. E. , Gründlingh M. L.
Published: March 2014

An international research programme of enormous scope, WOCE (World Ocean Circulation Experiment), is being planned for the last decade of this century. It is aimed at increasing our knowledge and understanding of the world ocean circulation by a quantum leap, thereby contributing to a better understanding of world climate changes. This programme is of great interest to South Africa and, while lacking the resources of the larger countries. South Africans can make key contributions in certain specific areas and have started preparing to do so.
An experimental investigation of a new multiplex method for linear programming
Authors: Snyman J. A. , Van Rooyen M.
Published: March 2014

Karmarkar’s recent internal and iterative method for linear programming problems has resulted in a renewed interest in some older alternatives, other than the simplex method. Here a new multiplex and geometric method, which has some features in common with the older methods, is proposed and implemented. In this method the solution is found by following a gradient path through the interior of the feasible region and through subspaces of reduced dimension corresponding to the bounding hyper-surfaces of the feasible region. The path moves from an initial feasible point through a sequence of linear steps to a vertex of the polytope defined by the constraints. Although similar, the current method differs fundamentally from Rosen’s gradient projection method in that the successive search directions are obtained from the gradients of reduced problems of lesser dimension. These directions, when translated to the original space, do not necessarily correspond to the gradient projection directions. Once a vertex has been reached the new algorithm determines whether or not it is optimal by applying a simple perturbation procedure for which the perturbed points are generated as a by-product of the computed path to the vertex. If not optimal the algorithm proceeds by restarting from a perturbed point (on a suitable edge) with increased function value and the path is continued until the next vertex is reached. It is shown that the results of this experimental investigation of this method is promising since it has successfully been applied to a variety of test problems.
Economic exploitation of the photosynthetic process: the basis of agricultural production
Authors: Hammes P. S.
Published: March 2014

Crop production is based on the photosynthetic process. Effective cropping systems are only attainable by optimising the size, active duration and effectivity of the photosynthesizing leaf canopy in the field. The extent of photosynthesis on a farm scale is impressive. A typical maize crop on one hectare of land utilises approximately 20 t. carbon dioxide, which is recovered from as much as 60 000 t. of air. Even highly productive cropping systems convert available radiation from the sun into chemical energy with an efficiency of less than 5%. Dramatic increases in crop yields may be attained in future, as has been the case in the past, as the process of photosynthesis is exploited with increasing skill.
The mushrooms of Pretoria and surroundings
Authors: Van der Westhuizen G. C. A. , Eicker A.
Published: March 2014

As a result of an increasing interest in mushrooms and demand for information on South African species, a list is provided of 106 species of the Order Agaricales, excluding the Polyporaceae, that have been recorded to date in the municipal areas of Pretoria, Pretoria North and Verwoerdburg. Twenty of the most common species are briefly described and illustrated. The occurence of mushrooms in this area is compared with their occurrence and distribution in other regions of South Africa. It is hoped that this information may serve as a basis for similar studies of the mushroom floras of other regions in order to extend the knowledge of the mushroom flora of South Africa.
Successful transcervical embryo transfer in two strains of mice
Authors: De Milander C. , Wimmers M. S. E. , Van der Merwe J. V. , Fourie F. Le R.
Published: March 2014

Two strains of mice (a black Balb/C x C5 BL and a white NMRI strain) were stimulated to superovulate and allowed to copulate with males of a similar strain. Blastocysts were obtained from black donor animals after cervical dislocation and flushing of the fallopian tubes 3,5 days after copulation. A total of 460 blastocysts were flushed and 6 blastocysts were transfered to each of the 71 white surrogate individuals which had copulated 2,5 days previously. A total of 51 births were documented with a 31,4% occurrence of black phenotypic animals in the litter.
Summary on Bayes estimation and hypothesis testing
Authors: De Waal D. J.
Published: March 2014

Although Bayes’ theorem was published in 1764, it is only recently that Bayesian procedures were used in practice in statistical analyses. Many developments have taken place and are still taking place in the areas of decision theory and group decision making. Two aspects, namely that of estimation and tests of hypotheses, will be looked into. This is the area of statistical inference mainly concerned with Mathematical Statistics.
The origin of life
Authors: Van Hoven W.
Published: March 2014

For many centuries scientists have been debating the question of how life on earth originated. With the increase in knowledge and technology in the twentieth century, realistic explanations are around with regard to the nature of life and its origin. One thought is that life has always existed, while a thought which is discussed deals with life originating as a slow and natural process following the big bang. Long after the big bang primitive earth formed, followed by the formation of prebiotic organic compounds. As these compounds became more concentrated they reacted spontaneously into elementary precursors of life such as amino acids and proteins.
Water availability and demand in the development regions of South Africa
Authors: De Villiers A. B. , Viviers W. , Van Wyk L. A.
Published: March 2014

The availability of water data in the development regions is at present insufficient. This is due to the fact that water supply and demand is calculated for the physical drainage regions (watersheds), while the development regions do not correspond with the drainage regions. The necessary calculations can accordingly presently not be made. In this paper this problem is addressed.
Erosion hazard in the Tugela Basin
Authors: Pretorius J. R. , Cooks J. , Marais D. W.
Published: March 2014

The extent of the soil erosion problem in South Africa as well as the various models which have been used in other parts of the world to quantify the problem are mentioned. It is indicated that these models are not designed to determine the potential danger of erosion. The model suggested in this study can be used to determine the potential danger of erosion in any area using only four variables, viz, erosivity, gradient, soil erodibility and plant cover.
A review of the mechanisms of the olefin metathesis reaction
Authors: Vosloo H. C. M. , Du Plessis J. A. K.
Published: March 2014

During the olefin metathesis reaction carbon-carbon double bonds are broken and rearranged to give a redistribution of alkilydene groups. A review of the different mechanistic approaches is given under the headings: The pairwise mechanism; The metal carbene chain mechanism with reference to the formation of the carbene and metallacyclobutane intermediate; The reactions of the olefins; and The degradation of unsaturated polymers.
The present status of organ transplantation
Authors: Mieny C. J.
Published: March 2014

Organ transplantation has improved dramatically during the last decade. In spite of this a worldwide lack of donors still exists. There are sufficient numbers of potential donors available, but only 10% are utilised in practice. Investigations have shown that the main reason for this state of affairs is not reluctance of relatives to give permission for donation, but rather reluctance or even resistance from attending physicians to request permission. The reasons for this are complex and include such factors as ignorance, lack of commitment and reluctance to accept the greater workload that such involvement would demand. To combat this problem, a number of countries have passed legislation to compel doctors to ask permission for donation in every instance of brain death in suitable patients. The reasons for the greater success with organ transplantation are varied. Surgical techniques, especially in such technically difficult procedures as liver transplantation and heart-lung transplantations have shown considerable progress.
The importance of the magnitude and duration of the polarizing magnetic field in the sensor of the proton magnetometer
Authors: Hancke G. P.
Published: March 2014

The most important factors affecting this free precession of protons in the earth’s magnetic field are examined. It is shown that when designing a proton magnetometer sensor, the polarization time and the magnitude of the polarization field must be kept in mind.
Water availability and demand in the humid and arid regions within development regions of South Africa
Authors: De Villiers A. B. , Van Wyk L. A. , Viviers W.
Published: March 2014

A method has been developed to distinguish between water supply and demand in individual development regions which contain distinct humid and arid to subarid areas. Development regions A and D have heterogeneous climatic distributions within their borders and are dealt with in this regard. These regions can be divided into arid and humid areas. A magisterial district was considered to be humid when the average annual rainfall is more than 400 mm over more than 50 percent of its total area. The water availability and demand for each of the districts (whether humid or arid) were calculated on a pro rata basis according to the area each district occupies within the various secondary drainage basins. The results obtained in this study show great promise to divide the regions into arid and humid areas for more accurate and detailed planning within the development regions.
Mass transfer parameters in spray columns
Authors: Rautenbach A. J. , Kornelius G.
Published: March 2014

To determine mass transfer parameters in spray columns the spray characteristics are required. A photographic technique that allows determination of these characteristics of wash oil sprayed through solid nozzles is described. Special precautions had to be taken because wash oil rendered the column walls opaque. Results are given for a specific nozzle as function of liquid and countercurrent gas flow rate.
Weakly-projective covers for left R-modules
Authors: Esterhuyse A.
Published: March 2014

All the necessary definitions are given in the introduction. Since it is not true that every left R-module possesses a projective cover, as is the case with injective hulls, it is the aim of this paper to consider a weakened form of a projective cover. In section 2 the concept of a weakly-projective cover is defined and developed. In section 3 this concept is compared with that of a quasi-projective cover. For example it is shown that in the case where a quasi-projective cover can he obtained from an existing projective cover, this quasi-projective cover is nothing more than a weakly-projective cover [Theorem 3.4].
Aspects of the moult, morphology and anatomy of rock pigeons
Authors: Kok A. C. , Kok O. B.
Published: March 2014

Aspects of the morphology and anatomy of rock pigeons (Columba guinea) were investigated. Moulting apparently takes place throughout the year at a relatively low intensity. Marked peaks in moulting could only be distinguished for the primaries, secondaries and tail feathers of males. The renewal process for females takes place more irregularly. Apart from the bill dimensions, all standard body measurements of adult males are significantly larger than those of females. The opposite tendency occurs in immatures. Seasonal variation in liver and body mass as well as visible fat content of adult individuals can probably be related to breeding activities and the availability of seasonally abundant food sources. In comparison to the other populations sampled, considerable differences in body mass and fat content were noted for the pigeons from South West Africa.
Economic evaluation of resonable nutrition support
Authors: Hu Wen , Yu Feng-mei
Published: March 2014

As an indispensable part of modern clinical therapeutics, nutrition support plays an important role in improving quality of life and prognosis for patients. In this paper, economic evaluation of practicing nutrition support as well as different ways and administrative patterns of nutrition support was provided to clarify how to obtain the optimal economic benefit during practicing nutrition support.
Effectiveness and safety of nicotine replacement therapy: A systematic review
Authors: Verma Kanika Gupta , Verma Pradhuman , Basavaraju Suman
Published: March 2014

Nicotine replacement therapy (NRT) is the use of various forms of nicotine delivery methods intended to replace the nicotine obtained from smoking or other tobacco usage. This reduces the withdrawal symptoms associated with smoking cessation and helps resist the urge to smoke cigarettes. The aim of this review is to determine the effectiveness of the different forms of NRT (chewing gum, transdermal patches, nasal spray, inhalers, and tablets) in achieving asceticism from cigarettes. As a method of delivering nicotine into the bloodstream, NRT is thought to be a comparatively less-dangerous method than tobacco smoking.
Effect of smoke and non-smoke tobacco on nitric oxide levels in diabetic patients
Authors: Das Liza , Mishra Arvind , Mahdi Abbas Ali , Shankar Singh Amit
Published: March 2014

Objective: Diabetes mellitus confers an increased cardiometabolic risk in affected individuals. Several mechanisms underlie this equation, but endothelial dysfunction has been implicated as the final common pathway by several studies. Endogenous nitric oxide (NO) is one of the principal molecules mediating normal endothelial vasodilation. This study was aimed at ascertaining the effects of smoke and non-smoke tobacco, both of which are commonly used by Indians, on the serum NO levels. Materials and Methods: A total of 208 type 2 diabetic patients attending the diabetes clinic were enrolled in this study. Data on age, gender, smoking, and tobacco chewing were collected, and the serum levels of NO determined using nitrate reductase and Griess Reagent which converts nitrite to a deep purple azo compound. The amount of the azochromophore accurately reflected the amount of NO in the samples. Results: The mean value of serum NO in smokers was 54.92 μmol/L, as compared to 60.60 μmol/L in non-smokers. The mean value of serum NO in tobacco chewers was 57.32 μmol/L and in tobacco non-chewers was 60.61 μmol/L. In this study, a near-significant association was found between the low serum levels of NO in smokers as compared to nonsmokers. But there was no significant association of serum NO levels in tobacco chewers and non-tobacco chewers. Conclusion: In this study, the difference in effects of different forms of nicotine usage on the NO levels was assessed, as it provides an insight into the mechanism of the effects of oral versus inhaled forms of nicotine use. In conclusion, new facts have been elucidated in this study, and to the best of our knowledge, this is the first comparison of smoke and nonsmoke tobacco in relation to the serum levels of NO for estimating the burden of vascular risk with various forms of tobacco use in diabetes.
Virulence Factors of Helicobacter pylori: A Review
Authors: Roesler Bruna M. , Rabelo-Gonçalves Elizabeth M.A. , Zeitune José M.R.
Published: March 2014

Helicobacter pylori is a spiral-shaped Gram-negative bacterium that colonizes the human stomach and can establish a long-term infection of the gastric mucosa, a condition that affects the relative risk of developing various clinical disorders of the upper gastrointestinal tract, such as chronic gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. H. pylori presents a high-level of genetic diversity, which can be an important factor in its adaptation to the host stomach and also for the clinical outcome of infection. There are important H. pylori virulence factors that, along with host characteristics and the external environment, have been associated with the different occurrences of diseases. This review is aimed to analyzing and summarizing the main of them and possible associations with the clinical outcome.
Sharpening 'Manin-Mumford' for certain algebraic groups in dimension 2
Authors: Corvaja Pietro , Masser David , Zannier Umberto
Published: March 2014

The present paper arises from the extensions of the Manin-Mumford conjecture, where we shall focus on the case of (complex connected) commutative algebraic groups

G

of dimension

2

. This context predicts finiteness for the set of torsion points in an algebraic curve inside

G

, unless the curve is 'special', i.e. a translate of an algebraic subgroup of

G

. Here we shall consider not merely the set of torsion points, but its topological closure in

G

(which equals the maximal compact subgroup). In the case of abelian varieties this closure is the whole space, but this is not so for other groups

G

; actually, we shall prove that in certain cases (where a natural dimensional condition is fulfilled) the intersection of this larger set with a non-special curve must still be a finite set. Beyond this, in the paper we shall briefly review some of the basic algebraic theory of group extensions of an elliptic curve by the additive group

\mathbb G_{\rm a}

, which are especially relevant in the said result. We shall conclude by stating some general questions in the same direction and discussing some simple examples. The paper concludes with the reproduction of a letter of Serre (whom we thank for his permission) to the second author, explaining how to obtain explicit projective embeddings of the said group extensions.