Effects of Staggering Formation Maneuvers on the Magnetospheric Multi-Scale Mission Trajectories

Formation maneuvering for the MMS mission is accomplished by executing a two-burn transfer for each spacecraft to achieve a set of desired states. Because the same radio frequency is shared by all four spacecraft, only one spacecraft can execute a maneuver at any given time. Therefore, the maneuver execution epochs for the MMS spacecraft must be staggered. The selection of the staggered maneuver sequence has a significant effect on the propellant usage and the spacecraft close-approach profile. A method for selecting a favorable maneuver sequence is proposed and measured in terms of propellant and safety

Alvarado vs. Pediatric Appendicitis Score (PAS) in Acute Appendicitis of Children

Introduction: Acute appendicitis in children is associated with morbidity and mortality due to late diagnosis. Several scoring systems, such as Alvarado and PAS have been developed to help diagnose acute appendicitis in children to make the most accurate and prompt decision. The purpose of this study was to compare the efficacy and diagnostic value of these scoring systems. Materials and Methods: In this cross-sectional study, 130 children aged 5-14 with suspected acute appendicitis were included. After the collection of demographic data, all patients were scored by Alvarado and PAS systems. The decision for surgery was made by a surgeon, independently of these scores. The diagnosis of acute appendicitis was affirmed by surgical and pathologic findings. Results: Male: Female ratio was 1.32:1, and the average age of the patients were 9.2±2.7 years. The mean Alvarado and PAS scores were higher in patients with positive pathologic findings. Neutrophilia >75% and RLQ tenderness had the highest relationship with the diagnosis of the disease. The diagnostic value of Alvarado was higher than PAS concerning the area under the ROC curve. The cutoff point of 7 was associated with a sensitivity of 74.5% and specificity of 66.7% for the Alvarado score, and a sensitivity of 58.5% and specificity of 79.2% for the PAS score. Conclusions: The results showed the high sensitivity of Alvarado and the high specificity of PAS. However, the sensitivity, specificity, PPV, and NPV of these criteria were not satisfactory for the confirmation of the diagnosis

Comparison of Magnetospheric MultiScale (MMS) Formation Design Algorithms

The MMS mission consists of four identical spinning spacecraft in a tetrahedron-like formation during predefined orbital regions-of-interest [1]. The MMS formation will fly about a highly eccentric orbit to study magnetic reconnection in the Earth.s magnetosphere. The mission is divided in two main science phases of markedly different orbit size. Phase 1 is a 1.2 R(sub E) x 12 R(sub E) (R(sub E) equals one Earth radius) orbit phase where science will be performed on the day-side of the magnetosphere, and Phase 2 is a 1.2 R(sub E) x 25 R(sub E) orbit phase where science will be performed on the night-side of the magnetosphere. For each phase, the MMS formation initially will fly a series of tetrahedron sizes ranging between 10-km and 400-km to assist the science team in determining the best value for the remainder of the phase. This paper presents a preliminary comparison of the algorithms currently available to determine desired MMS formation states. After a brief description of the MMS formation flying metrics and associated requirements, the five formation design algorithm combinations considered here are presented. Monte Carlo simulations determine the performance of each algorithm defined in terms of formation lifetime and fuel consumption. Preliminary results focusing on the smaller formation size for Phase 1 are discussed and the conclusions are presented along with indications for future work

Statistical Studies of Fading in Underwater Wireless Optical Channels in the Presence of Air Bubble, Temperature, and Salinity Random Variations (Long Version)

Optical signal propagation through underwater channels is affected by three main degrading phenomena, namely absorption, scattering, and fading. In this paper, we experimentally study the statistical distribution of intensity fluctuations in underwater wireless optical channels with random temperature and salinity variations as well as the presence of air bubbles. In particular, we define different scenarios to produce random fluctuations on the water refractive index across the propagation path, and then examine the accuracy of various statistical distributions in terms of their goodness of fit to the experimental data. We also obtain the channel coherence time to address the average period of fading temporal variations. The scenarios under consideration cover a wide range of scintillation index from weak to strong turbulence. Moreover, the effects of beam-collimator at the transmitter side and aperture averaging lens at the receiver side are experimentally investigated. We show that the use of a transmitter beam-collimator and/or a receiver aperture averaging lens suits single-lobe distributions such that the generalized Gamma and exponential Weibull distributions can excellently match the histograms of the acquired data. Our experimental results further reveal that the channel coherence time is on the order of $10^{-3}$ seconds and larger which implies to the slow fading turbulent channels

A Case of Giant Gastric Trichobezoar

Trichobezoar is an unusual form of bezoar found in the digestive tract, mostly in the stomach. The patient is often a female in her adolescence who pulls out and swallows her hair. This habit could stem from anxiety and the trichotillomania disorder. These hairs accumulate in the stomach and cause gastrointestinal symptoms. Our patient is a 14-year-old girl who came to us complaining of abdominal pain. Upon further evaluation by ultrasonography and endoscopy, trichobezoar was diagnosed. Laparotomy and gastrotomy were performed,and a large bezoar was removed. Although the occurrence of trichobezoar is rare, surgeons should always consider the situation in patients with vague gastrointestinal symptoms and psychological problems, especially in young female individuals

Mothers’ Experiences of the Strategies Used to Gain Successful Exclusive Breastfeeding: A Qualitative Study

Introduction: Effective and appropriate interventions used by nursing mothers in exclusive breast feeding, in accordance with existing conditions, can have a great effect on the maintenance, continuity and promotion of breastfeeding. So, identifying these successful strategies is essential to make future breast feeding health plans for mothers and infants, and to ensure exclusive breastfeeding. Method: This was a qualitative study of conventional content analysis conducted in the year 2014. Participants included sixteen lactating mothers of kids up to one year old, and of successful experience in exclusive breastfeeding, who have refereed to health centers in Golestan and Mazandaran universities of medical sciences, Iran. Their experiences on the strategies used successfully in the first six months of exclusive breastfeeding were collected through unstructured and in-depth interviews. Sampling was purposive and was continued until reaching data saturation. The study data were analyzed using constant comparison analysis technique. Results: Eight main themes related to the nature and dimensions of mothers’ understanding of the strategies used to gain successful exclusive breastfeeding were extracted. These themes were as “comfortable and pleasant preparation before breastfeeding”, “information from reliable sources”, “lifestyle adjustment to breastfeeding”, “intelligent resiliency”, “resolutions for infant’s reluctance in breastfeeding”, “strengthening and ensuring the adequacy of milk and lactation”, “breast care during breastfeeding”, and “the use of religious instructions”. Conclusion: It is recommended to consider the role and eminence of mothers, and their successful strategies and guidelines related to successful exclusive breastfeeding seriously in codification of health care policies. Keywords: Breastfeeding, Exclusive breastfeeding, Empowerment, Mothers, Strategies, Qualitative researc

Relation of intelligence quotient and body mass index in preschool children: a community-based cross-sectional study

Objective:Overweight and obesity in children is a global problem. Besides physical effects, obesity has harmful psychological effects on children.Methods:We carried out cross-sectional community-based study to investigate the relation between body mass index (BMI) and cognitive functioning in preschool children. Thirteen socioeconomical elements of 1151 children were measured and analyzed based on their intelligence quotient (IQ) test results. Thirteen out of 33 provinces were selected randomly, and schools were selected as clusters in rural and urban areas. Descriptive statistics, t-test, analysis of variance and regression were used when appropriate.Results:Our analysis showed that IQ was associated with household income, place of residence, delivery type, type of infant feeding and father's and mother's education level (P<0.001 for all). Using penalized linear regression for eliminating the impact of confounding factor, our study shows that, living in metropolitan (β=2.411) and urban areas (β=2.761), the level of participants' father's education (β=5.251) was positively and BMI (β=−0.594) was negatively related with IQ test results.ConclusionsThe findings of the present study showed that a lower IQ score is associated with higher BMI. However, this relation appears to be largely mediated when the socioeconomic status was considered

Postnatal quality of life in women after normal vaginal delivery and caesarean section

<p>Abstract</p> <p>Background</p> <p>Caesarean section might increase the incidence of surgical interventions and problems resulting from hospitalization and thus affecting quality of life in women after delivery. This study aimed to compare quality of life in women after normal delivery and caesarean section.</p> <p>Methods</p> <p>This was a prospective study. A sample of women with normal delivery and caesarean section from 5 health care centers in Isfahan, Iran were entered into the study. Quality of life was measured using the SF-36 at two points in time (time 1: 6 to 8 weeks after delivery; time 2: 12 to 14 weeks after delivery). Data were analyzed to compare quality of life in the two study groups.</p> <p>Results</p> <p>In all 100 women were interviewed (50 with normal delivery and 50 with caesarean section). Postnatal quality of life in both groups was improved from time1 to time 2. However, comparing the mean scores between the normal and caesarean delivery groups the results showed that in general the normal vaginal delivery group had a better quality of life for almost all subscales in both assessment times. The differences were significant for vitality (mean score 62.9 vs. 54.4 P = 0.03) and mental health (mean score 75.1 vs. 66.7, P = 0.03) at first assessment and for physical functioning (mean score 88.4 vs. 81.5, P = 0.03) at second evaluation. However, comparing the findings within each group the analysis showed that the normal vaginal delivery group improved more on physical health related quality of life while the caesarean section group improved more on mental health related quality of life.</p> <p>Conclusion</p> <p>Although the study did not show a clear cut benefit in favor of either methods of delivery that are normal vaginal delivery or caesarean section, the findings suggest that normal vaginal delivery might lead to a better quality of life especially resulting in a superior physical health. Indeed in the absence of medical indications normal vaginal delivery might be better to be considered as the first priority in term pregnancy.</p

Invariant Solar Sail Formations in Elliptical Sun-Synchronous Orbits

Current and past missions that study the Earth\u27s geomagnetic tail require multiple spacecraft to fly in formation about a highly eccentric Keplerian reference orbit that has its apogee inside a predefined science region of interest. Because the geomagnetic tail is directed along the Sun-Earth line and therefore rotates annually, inertially fixed Keplerian orbits are only aligned with the geomagnetic tail once per year. This limitation reduces the duration of the science phase to less than a few months annually. Solar sails are capable of creating non-Keplerian, Sun-synchronous orbits that rotate with the geomagnetic tail. A solar sail flying in a Sun-synchronous orbit will have a continuous presence in the geomagnetic tail throughout the entire year, which significantly improves the in situ observations of the magnetosphere. To achieve a Sun-synchronous orbit, a solar sail is required to maintain a Sun-pointing attitude, which leads to the artificial precession of the orbit apse line in a Sun-synchronous manner, leaving the orbit apogee inside the science region of interest throughout entire the year. To study the spatial and temporal variations of plasma in the highly dynamic environment of the magnetosphere, multiple spacecraft must fly in a formation. The objective for this dissertation is to investigate the feasibility of solar sail formation flying in the Earth-centered, Sun-synchronous orbit regime. The focus of this effort is to enable formation flying for a group of solar sails that maintain a nominally fixed Sun-pointing attitude during formation flight, solely for the purpose of precessing their orbit apse lines Sun-synchronously. A fixed-attitude solar sail formation is motivated by the difficulties in the simultaneous control of orbit and attitude in flying solar sails. First, the secular rates of the orbital elements resulting from the effects of solar radiation pressure (SRP) are determined using averaging theory for a Sun-pointing attitude sail. These averaged rates are used to analytically derive the necessary conditions for a drift-free solar sail formation in Sun-synchronous orbits, assuming a fixed Sun-pointing orientation for each sail in formation. Next, the problem of formation design is solved using nonlinear programming for optimal two-craft, three-craft, and four-craft solar sail formations, in terms of formation quality and stability. Finally, the problem of formation establishment is addressed using optimal control theory, assuming that the sails are capable of making small changes to their orientations with respect to the Sun. These studies demonstrate the feasibility of solar sail formation flying for exploring the geomagnetic tail and improve upon previous work, which only considered unnatural relative motions that require continuous use of active control to remain in formation

Corresponding Author Effects of Creatine and Glutamine Supplements in Comparison with Proper Nutrition on Performance Factors of Wrestlers 1 Glutamine Supplements in Comparison with Proper Nutrition on Performance Factors of Wrestlers

ABSTRACT Aim; The aim of this study was to investigate the effects of glutamine and creatine supplements and proper nutrition on hand grip strength and agility of athletes. Materials and Methods: The samples for this study consisted of 28 elite wrestlers of Mazandaran province, aged 18 to 25 years old. They were randomly divided into four groups. Proper nutrition with carbohydrate solution made of 5% honey instead of water, creatine supplement group (0.3 g/Kg/ for 15 days), glutamine group (0.3 g/kg for 15 days), control group. After a usual warm-up exercises for 15 minutes, for the agility test, 9x4 agility test was performed and following a 10-min rest period, subjects used hand grip for the grip strength test; after 15 days of glutamine and creatine supplements and proper nutrition consumptions, the physical performance tests were conducted in the same condition. Statistical analyses were performed using SPSS software. Results: Statistical analysis of the grip strength and agility in post test showed significant difference between the proper nutrition, in comparison with the control group (p&lt;0.05). Therefore, it seems that through proper nutrition (which provides all necessary substances for an elite athlete) there is no need for these supplementation agents and the proper nutrition can be used as an alternative for these supplements. Conclusion: Our current investigation showed that proper nutrition can be used as a competent alternative for the common supplements such a creatine and glutamine