8,663 research outputs found
On electromagnetic interactions for massive mixed symmetry field
In this paper we investigate electromagnetic interactions for simplest
massive mixed symmetry field. Using frame-like gauge invariant formulation we
extend Fradkin-Vasiliev procedure, initially proposed for investigation of
gravitational interactions for massless particles in AdS space, to the case of
electromagnetic interactions for massive particles leaving in (A)dS space with
arbitrary value of cosmological constant including flat Minkowski space. At
first, as an illustration of general procedure, we re-derive our previous
results on massive spin 2 electromagnetic interactions and then we apply this
procedure to massive mixed symmetry field. These two cases are just the
simplest representatives of two general class of fields, namely completely
symmetric and mixed symmetry ones, and it is clear that the results obtained
admit straightforward generalization to higher spins as well.Comment: 17 pages. Some clarifications added. Version to appear in JHE
Spin 3 cubic vertices in a frame-like formalism
Till now most of the results on interaction vertices for massless higher spin
fields were obtained in a metric-like formalism using completely symmetric
(spin-)tensors. In this, the Lagrangians turn out to be very complicated and
the main reason is that the higher the spin one want to consider the more
derivatives one has to introduce. In this paper we show that such
investigations can be greatly simplified if one works in a frame-like
formalism. As an illustration we consider massless spin 3 particle and
reconstruct a number of vertices describing its interactions with lower spin 2,
1 and 0 ones. In all cases considered we give explicit expressions for the
Lagrangians and gauge transformations and check that the algebra of gauge
transformations is indeed closed.Comment: 17 pades, no figure
EFFECT OF POST-WELD HEAT TREATMENT ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ARC WELDED MEDIUM CARBON STEEL
Effect of post- weld heat treatment on the microstructure and mechanical properties of arc welded medium carbon steel was investigated. Medium carbon steel samples were butt- welded by using the shielded metal arc welding technique and, thereafter, heat treated by annealing, normalising and quench hardening in water. The microstructure of the as- welded and post- weld heated samples was characterised by means of optical microscopy while the hardness, toughness and tensile properties of the samples were determined by using Indentec universal hardness testing machine, Izod impact testing machine and Denison tensile testing machine respectively. The results of the optical microscopic test show that fine grains of pearlite in ferrite were obtained in normalized samples and martensite was also observed in quenched samples. On the other hand, mechanical property tests indicated that normalized welded specimens gave good combination of mechanical properties. http://dx.doi.org/10.4314/njt.v35i2.1
Hermite–Hadamard type inequalities for co-ordinated convex and qausi-convex functions and their applications
The effects of task instructions on motor learning of a relaxed phonation task
Abstract no. 3176postprintThe 38th Annual Symposium of the Voice Foundation: Care of the Professional Voice, Philadelphia, PA., 3-7 June 2009
Gauge fields in (A)dS within the unfolded approach: algebraic aspects
It has recently been shown that generalized connections of the (A)dS space
symmetry algebra provide an effective geometric and algebraic framework for all
types of gauge fields in (A)dS, both for massless and partially-massless. The
equations of motion are equipped with a nilpotent operator called
whose cohomology groups correspond to the dynamically relevant quantities like
differential gauge parameters, dynamical fields, gauge invariant field
equations, Bianchi identities etc. In the paper the -cohomology is
computed for all gauge theories of this type and the field-theoretical
interpretation is discussed. In the simplest cases the -cohomology is
equivalent to the ordinary Lie algebra cohomology.Comment: 59 pages, replaced with revised verio
Intelligent spider for Internet searching
As World Wide Web (WWW) based Internet services become more popular, information overload also becomes a pressing research problem. Difficulties with searching on the Internet get worse as the amount of information that is available increases. A scalable approach to support Internet search is critical to the success of Internet services and other current or future national information infrastructure (NII) applications. A new approach to build an intelligent personal spider (agent), which is based on automatic textual analysis of Internet documents, is proposed. Best first search and genetic algorithm have been tested to develop the intelligent spider. These personal spiders are able to dynamically and intelligently analyze the contents of the users' selected homepages as the starting point to search for the most relevant homepages based on the links and indexing. An intelligent spider must have the capability to make adjustments according to progress of searching in order to be an intelligent agent. However, the current searching engines do not have communication between the users and the robots. The spider presented in the paper uses Java to develop the user interface such that the users can adjust the control parameters according to the progress and observe the intermediate results. The performances of the genetic algorithm based and best first search based spiders are also reported.published_or_final_versio
Morphological pattern of endometrial biopsies in southwestern Nigeria
Background: Endometrium remains the most sensitive indicator of ovarian function and endometrial biopsy is one of the diagnostic procedures in endometrial pathology. The current study was carried out to examine the morphological pattern of endometrial biopsies in Ibadan, South-western Nigeria and compare the results with similar studies.Method: A retrospective study was undertaken to review all cases of endometrial biopsies received in the Department of Pathology, University College Hospital, Ibadan between January 1999 and December 2008. The patients’ data were retrieved from the surgical pathology daybooks and Histology Request forms. The neoplastic lesions were classified according to 2003 World Health Organization classification for endometrial neoplasms.Results: A total of 2,444 cases of endometrial biopsies were received during the 10-year study period. The functional endometrial changes were the most common histopathological diagnostic category, accounting for 53.8% (1035) of cases. Other pathological diagnoses included endometritis (7.8%), simple endometrial hyperplasia (5.8%), partial hydatidiform mole (2.3%), complete hydatidiform mole (2.1%) and malignant neoplastic lesions (3.9%). Infertility was the most common (57%) indication for endometrial biopsies followed by uterine bleeding (33%) while the least common clinical indication were the menstrual disorders (10%).Conclusion: The functional endometrial changes account for the highest morphological patterns while malignant lesions account for the least pattern of the endometrial biopsies evaluated for etiological basis of infertility, uterine bleeding and menstrual disorders in Ibadan. Infertility was the commonest indication for endometrial biopsies while the least common clinical indication was menstrual disorders.Keywords: Endometrium, Biopsies, Morphology, Ibada
Availability of adequately iodized salt at the household level in Ethiopia: A systematic review and meta-analysis
BackgroundIodine deficiency disorder (IDD) is a global, regional, and national public health problem that is preventable. Universal salt iodization is a worldwide accepted strategy to prevent IDD. The level of iodine in the salt should be adequate at the household level (≥15ppm). Though there was fragmented evidence on the proportion of adequately iodized salt at the household level in Ethiopia, the national level proportion of adequately iodized salt at the household level was remaining unknown. Therefore, this systematic review and meta-analysis estimated the pooled proportion of adequately iodized salt at the household level in Ethiopia from 2013-2020.MethodWe systematically searched the databases: PubMed/MEDLINE, Google Scholar, and Science Direct for studies conducted in Ethiopia on the availability of adequately iodized salt at the household level since 2013. We have included observational studies, which were published between January first, 2013, and 10 August 2020. The report was compiled according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The quality of included studies was scored based on the Newcastle Ottawa quality assessment scale adapted for cross-sectional studies. The data were extracted in Microsoft excel and analyzed using Stata version 14.1 software. We employed a random-effects model to estimate the pooled proportion of adequately iodized salt at the household level in Ethiopia. The presence of statistical heterogeneity within the included studies was evaluated using the I-squared statistic. We used Egger's regression test to identify evidence of publication bias. The pooled proportion with a 95% confidence interval (CI) was presented using tables and forest plots.ResultsWe screened a total of 195 articles. Of these, 28 studies (with 15561 households) were included in the final systematic review and meta-analysis. In Ethiopia, the pooled proportion of adequately iodized salt at the household level was 37% (95% CI: 28, 46%). The subgroup analyses of 28 studies by residence revealed that the pooled proportion of adequately iodized salt at the household level was 32% (95% CI: 29, 35%) and 48% (95% CI: 31, 66%) in rural and urban areas, respectively. Based on geographic location, the highest proportion was found in Addis Ababa (81%; 95%CI: 78, 83), and the lowest proportion found in Dire Dawa (20%; 95%CI: 17, 22). Besides, the proportion of adequately iodized salt at the household level was significantly increased during 2017-2020 (42%; 95% CI: 30, 53%) as compared with 2013-2016 (27%; 95% CI: 17, 39%).ConclusionsIn Ethiopia, the pooled proportion of adequately iodized salt at the household level was very low as compared to the world health organization's recommendation. Thus, the Federal Ministry of Health of Ethiopia and different stakeholders should give more attention to improve the proportion of adequately iodized salt at the household level
Parent formulation at the Lagrangian level
The recently proposed first-order parent formalism at the level of equations
of motion is specialized to the case of Lagrangian systems. It is shown that
for diffeomorphism-invariant theories the parent formulation takes the form of
an AKSZ-type sigma model. The proposed formulation can be also seen as a
Lagrangian version of the BV-BRST extension of the Vasiliev unfolded approach.
We also discuss its possible interpretation as a multidimensional
generalization of the Hamiltonian BFV--BRST formalism. The general construction
is illustrated by examples of (parametrized) mechanics, relativistic particle,
Yang--Mills theory, and gravity.Comment: 26 pages, discussion of the truncation extended, typos corrected,
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