OFF-FARM WORK PARTICIPATION, OFF-FARM LABOR SUPPLY AND ON-FARM LABOR DEMAND OF U.S. FARM OPERATORS

The paper presents econometric evidence on off-farm work participation, off-farm hours of work, and on-farm hours of work for U.S. farm operators using a national sample of farmers for the USDA's 1991 Farm Costs and Return Survey.Farm Management, Labor and Human Capital, Research Methods/ Statistical Methods,

Twisted topological structures related to M-branes II: Twisted Wu and Wu^c structures

Studying the topological aspects of M-branes in M-theory leads to various structures related to Wu classes. First we interpret Wu classes themselves as twisted classes and then define twisted notions of Wu structures. These generalize many known structures, including Pin^- structures, twisted Spin structures in the sense of Distler-Freed-Moore, Wu-twisted differential cocycles appearing in the work of Belov-Moore, as well as ones introduced by the author, such as twisted Membrane and twisted String^c structures. In addition, we introduce Wu^c structures, which generalize Pin^c structures, as well as their twisted versions. We show how these structures generalize and encode the usual structures defined via Stiefel-Whitney classes.Comment: 20 page

Study of potential activity of clove oil 10 % emulsifiable concentrate formulation on Two-spotted spider Mite Tetranychus urticae Koch (Acari: Tetranychidae)

Clove oil is reported to have a great range of biological activities against many species of pests; termites, cockroaches, aphids, weevils and moths, and many different usages such as perfume and food flavoring agent. This study aimed to determine the acaricidal activity of clove oil emulsifiable concentrate new formulation against two-spotted spider mites Tetranychus urticae. Clove oil was formulated as 10 % emulsifiable concentrate (EC). The new formula passed successfully all physical and chemical tests reported for emulsifiable concentrates. It was then tested biologically on the individuals of two-spotted spider mite T. urticae Koch (Acari: Tetranychidae) on two host plants beans and squash under laboratory conditions. In both cases, there were a direct relationship between the increase in the concentration of the formulation and the percentage of inhibition on the individuals of the two-spotted spider mite, after 72 hours of treatment, at concentrations of 20, 40, and 80 mg/ml the new formulation showed 10.30, 44.8, and 75 percent inhibition, respectively in case of beans, while squash at the same concentrations and for the same period of treatment showed 33.3, 40.7, and 51.9 percent inhibition, but the effect in case of beans was greater than that in case of squash as its EC50 value was lower than that in case of squash. In the case of the former, it was 39.81 mg/ml, whereas in the case of the latter, it was 79.43 mg/ml. Therefore, the new clove oil formulation can be used to combat the two-spotted spider mite

Simulation of Chlorine Decay in Water Distribution Networks Using EPANET – Case Study

Deterioration of water quality in distribution networks has a great impact on human health and public acceptance of tap water reaching them. Residual chlorine should be maintained through network pipes to prevent contamination and microbial regrowth. This paper investigates the ability of EPANET 2.0, a free software developed by United States Environment Protection Agency (USEPA), to simulate residual chlorine decay through water networks, taking water-age analyses into consideration, and assesses the feasibility of using it as a measuring and controlling tool to estimate and predict chlorine concentration at different water network points. A study was performed on drinking water network of 6th of October city, where field measurements were done, while data required as program inputs were taken from the daily records of the 6th of October and El-Shaikh Zayed WTPs. The network model was calibrated to minimize error in program results. Errors were evaluated using statistical analyses. The calculated concentrations by the calibrated model were very close to the actual concentrations measured in field at different sampling points for different sampling days. Moreover, EPANET showed that for the water network concerned in this study, chlorine concentrations at network extremities did not recede 0.5 mg/l, the minimum allowable limit established in the Egyptian Code of Practice (ECP), even for those points having water age greater than 24 hours. Keywords: chlorine decay, water quality, water distribution networks, EPANET, water-ag

Pyloromyotomy for infantile hypertrophic pyloric stenosis using a modification of the Tan and Bianchi circumumbilical approach

Background/purpose Different approaches have been advocated for pyloromyotomy.  Since the introduction of umbilical pyloromyotomy, a number of studies have shown that it is as safe as the traditional right upper quadrant approach with superior  cosmetic results. The aim of this study was to assess the feasibility and the safety  of pyloromyotomy for infantile hyprtrophic pyloric stenosis using a modification of the Tan–Bianchi approach.Patients and methods Over a period of 2 years, 20 infants with infantile  hypertrophic pyloric stenosis have been clinically evaluated. The umbilical approach was modified so that a transverse muscle cutting incision rather than a longitudinal midline linea alba incision was performed.Results The total number of cases included in this study was 20 [16 male (80%)  and four female (20%) patients]. Their ages ranged from 23 to 60 days (average  42.6 ±13.54 days), and their weights ranged from 2700 to 4000 g (mean 3605± 437.4 g). Pyloromyotomy was performed safely with negligible blood loss. Four cases of serosal tear occurred, with an incidence of 20%. None of our cases showed significant complications. The mean operating time was 52.5 ± 5.073 min. The postoperative hospital stay ranged from 24 to 72 h. The postoperative course was uneventful in all patients, and, on follow-up, the circumumbilical incision left an almost undetectable scar.Conclusion Pyloromyotomy for infantile hypertrophic pyloric stenosis using the modified Tan and Bianchi technique is feasible and safe, having an accepted operative time, early initiation of postoperative feeding, and short hospital stay. This modification combines the advantage of circumumbilical incision with its better cosmetic results and right transverse upper abdominal approach with its easy and feasible access to the pyloric mass.Keywords: operative intervention, pyloric stenosis, Tan–Bianchi approac

Reduction glossectomy for macroglossia in children

Background/aim: Although several surgical techniques have been described for reduction glossectomy in children, many general pediatric surgeons are still skeptical about the treatment of patients with macroglossia because of potential surgical complications. The aim of this study was to describe our initial surgical experience with reduction glossectomy in a series of eight patients with macroglossia.Materials and methods: A retrospective file review was carried out for all patients who underwent reduction glossectomy during the period from October 2009 to December 2014. Charts were designed to collect the following data from the patients’ files: age; etiology of macroglossia; and full clinical examination including the functional respiration, deglutition, phonation deficit, and dental occlusion alterations.Results: The records of eight patients were retrieved. Five patients, in whom macroglossia affected the tongue width and length, underwent peripheral glossectomy, whereas two patients, in whom macroglossia affected the tongue in all directions, underwent key-hole glossectomy. In one patient in whom only half the tongue was affected, a central longitudinal strip was excised. Motor and sensory  functions, especially taste sensation, were not affected by resection. Speech articulation errors were corrected in cases that stared speech. One complication occurred in one patient who had undergone a key-hole glossectomy: wound infection, followed by partial wound disruption.Conclusion: Partial glossectomy for macroglossia in children is both feasible and safe. It results in minimal complications. Many clinical problems caused by the pathology improve after surgery repair. The recommended surgical technique should be based on the extent of involvement of the tongue.Keywords: Beckwith–Wiedemann syndrome, macroglossia, reduction glossectom

Integral group actions on symmetric spaces and discrete duality symmetries of supergravity theories

For $G(\mathbb{R})$ a split, simply connected, semisimple Lie group of rank $n$ and $K$ the maximal compact subgroup of $G$, we give a method for computing Iwasawa coordinates of $G/K$ using the Chevalley generators and the Steinberg presentation. When $G/K$ is a scalar coset for a supergravity theory in dimensions $\geq 3$, we determine the action of the integral form $G(\mathbb{Z})$ on $G/K$. We give explicit results for the action of the discrete $U$--duality groups $SL_2(\mathbb{Z})$ and $E_7(\mathbb{Z})$ on the scalar cosets $SL_2(\mathbb{R})/SO_2(\mathbb{R})$ and $E_{7(+7)}(\mathbb{R})/[SU(8,\mathbb{R})/\{\pm Id\}]$ for type IIB supergravity in ten dimensions and 11--dimensional supergravity in $D=4$ dimensions, respectively. For the former, we use this to determine the discrete U--duality transformations on the scalar sector in the Borel gauge and we describe the discrete symmetries of the dyonic charge lattice. We determine the spectrum--generating symmetry group for fundamental BPS solitons of type IIB supergravity in $D=10$ dimensions at the classical level and we propose an analog of this symmetry at the quantum level. We indicate how our methods can be used to study the orbits of discrete U--duality groups in general

Duality symmetry and the form fields of M-theory

In previous work we derived the topological terms in the M-theory action in terms of certain characters that we defined. In this paper, we propose the extention of these characters to include the dual fields. The unified treatment of the M-theory four-form field strength and its dual leads to several observations. In particular we elaborate on the possibility of a twisted cohomology theory with a twist given by degrees greater than three.Comment: 12 pages, modified material on the differentia