Descent guidance and mission planning for space shuttle

The Space Shuttle descent mission planning, mission design, deorbit targeting, and entry guidance have necessarily become interrelated because of the nature of the Orbiter's design and mission requirements. The desired descent trajectory has been formulated in a drag acceleration/relative velocity state space since nearly all of the vehicle's highly constraining flight limitations can be uniquely represented in this plane. Constraints and flight requirements that affect the descent are described. The guidance logic which allows the Orbiter to follow the designed trajectory, the impacts of contingency aborts and flightcrew interaction are discussed. The mission planning and guidance techniques remain essentially unchanged through the Shuttle flight test program and subsequent operational flights

Effects of single and mixed infections with wild type and genetically modified Helicoverpa armigera nucleopolyhedrovirus on movement behaviour of cotton bollworm larvae

Naturally occurring insect viruses can modify the behaviour of infected insects and thereby modulate virus transmission. Modifications of the virus genome could alter these behavioural effects. We studied the distance moved and the position of virus-killed cadavers of fourth instars of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) infected with a wild-type genotype of H. armigera nucleopolyhedrovirus (HaSNPV) or with one of two recombinant genotypes of this virus on cotton plants. The behavioural effects of virus infection were examined both in larvae infected with a single virus genotype, and in larvae challenged with mixtures of the wild-type and one of the recombinant viruses. An egt-negative virus variant caused more rapid death and lower virus yield in fourth instars, but egt-deletion did not produce consistent behavioural effects over three experiments, two under controlled glasshouse conditions and one in field cages. A recombinant virus containing the AaIT-(Androctonus australis Hector) insect-selective toxin gene, which expresses a neurotoxin derived from a scorpion, caused faster death and cadavers were found lower down the plant than insects infected with unmodified virus. Larvae that died from mixed infections of the AaIT-expressing recombinant and the wild-type virus died at positions significantly lower, compared to infection with the pure wild-type viral strain. The results indicate that transmission of egt-negative variants of HaSNPV are likely to be affected by lower virus yield, but not by behavioural effects of egt gene deletion. By contrast, the AaIT recombinant will produce lower virus yields as well as modified behaviour, which together can contribute to reduced virus transmission under field conditions. In addition, larvae infected with both the wild-type virus and the toxin recombinant behaved as larvae infected with the toxin recombinant only, which might be a positive factor for the risk assessment of such toxin recombinants in the environment

Reply to Comment on "Reevaluation of the parton distribution of strange quarks in the nucleon"

A Comment on the recently published reevaluation of the polarization-averaged parton distribution of strange quarks in the nucleon using final data on the multiplicities of charged kaons in semi-inclusive deep-inelastic scattering is reviewed. Important features of the comparison of one-dimensional projections of the multidimensional HERMES data are pointed out. A test of the leading-order extraction of xS(x) using the difference between charged-kaon multiplicities is repeated. The results are consistent with leading-order predictions within the uncertainties in the input data, and do not invalidate the earlier extraction of xS(x).Comment: Reply Comment to arXiv:1407.372

Association between nutritional status and subjective health status in chronically ill children attending special schools

Purpose: In hospitalized children with a chronic disease, malnutrition was associated with a lower subjective health status. In outpatient children with a chronic disease attending special schools, this association has never been studied. The aim of this study was to assess the association between nutritional status and subjective health status in chronically ill children attending special schools. Methods: Overall, 642 children, median age 9.8 years (IQR 7.7–11.5), 60 % male, 72 % Caucasian, were included in this prospective study in nine special schools for chronically ill children in the Netherlands. Overall malnutrition was assessed as: acute malnutrition (<−2 SDS for weight for height (WFH)) and chronic malnutrition (<−2 SDS for height for age). The malnutrition risk was assessed with the nutritional risk-screening tool STRONGkids. Subjective health status was assessed with EQ-5D. Results: Overall, 16 % of the children had overall malnutrition: 3 % acute and 13 % chronic malnutrition. Nurses reported ‘some/severe problems’ on the health status dimensions mobility (15 %), self-care (17 %), usual activities (19 %), pain/discomfort (22 %), and anxiety/depression (22 %) in chronically ill children. Their mean visual analogue scale score (VAS) was 73.0 (SD 11.1). Malnutrition, medication usage, and younger age explained 38 % of the variance of the VAS score. Conclusions: The presence of overall malnutrition in chronically ill children attending special schools was associated with lower subjective health status, especially in younger children and in those with chronic medication usage. Therefore, it is important to develop and use profile-screening tools to identify these children

Factors associated with laryngeal injury after intubation in children:a systematic review

Purpose: The purpose of this study is to evaluate all potential factors associated with laryngeal injury after endotracheal intubation in the pediatric population. Methods: A systematic literature search was conducted in Medline, Embase, Cochrane, web of science and Google scholar up to 20th of March 2023. We included all unique articles focusing on factors possibly associated with intubation-injury in pediatric patients. Two independent reviewers determined which articles were relevant by coming to a consensus, quality of evidence was rated using GRADE criteria. All articles were critically appraised according to the PRISMA guidelines. The articles were categorized in four outcome measures: post-extubation stridor, post-extubation upper airway obstruction (UAO) necessitating treatment, laryngeal injury found at laryngoscopy and a diagnosed laryngotracheal stenosis (LTS). Results: A total of 24 articles with a total of 15.520 patients were included. The incidence of post-extubation stridor varied between 1.0 and 30.3%, of post-extubation UAO necessitating treatment between 1.2 and 39.6%, of laryngeal injury found at laryngoscopy between 34.9 to 97.0% and of a diagnosed LTS between 0 and 11.1%. Although the literature is limited and quality of evidence very low, the level of sedation and gastro-esophageal reflux are the only confirmed associated factors with post-extubation laryngeal injury. The relation with age, weight, gender, duration of intubation, multiple intubations, traumatic intubation, tube size, absence of air leak and infection remain unresolved. The remaining factors are not associated with intubation injury. Conclusion: We clarify the role of the potential factors associated with laryngeal injury after endotracheal intubation in the pediatric population.</p

Functional consequences of sphingomyelinase-induced changes in erythrocyte membrane structure.

Inflammation enhances the secretion of sphingomyelinases (SMases). SMases catalyze the hydrolysis of sphingomyelin into phosphocholine and ceramide. In erythrocytes, ceramide formation leads to exposure of the removal signal phosphatidylserine (PS), creating a potential link between SMase activity and anemia of inflammation. Therefore, we studied the effects of SMase on various pathophysiologically relevant parameters of erythrocyte homeostasis. Time-lapse confocal microscopy revealed a SMase-induced transition from the discoid to a spherical shape, followed by PS exposure, and finally loss of cytoplasmic content. Also, SMase treatment resulted in ceramide-associated alterations in membrane-cytoskeleton interactions and membrane organization, including microdomain formation. Furthermore, we observed increases in membrane fragility, vesiculation and invagination, and large protein clusters. These changes were associated with enhanced erythrocyte retention in a spleen-mimicking model. Erythrocyte storage under blood bank conditions and during physiological aging increased the sensitivity to SMase. A low SMase activity already induced morphological and structural changes, demonstrating the potential of SMase to disturb erythrocyte homeostasis. Our analyses provide a comprehensive picture in which ceramide-induced changes in membrane microdomain organization disrupt the membrane-cytoskeleton interaction and membrane integrity, leading to vesiculation, reduced deformability, and finally loss of erythrocyte content. Understanding these processes is highly relevant for understanding anemia during chronic inflammation, especially in critically ill patients receiving blood transfusions

The launch of the ESPEN Special Interest Group in Paediatric Clinical Nutrition

Background &amp; aims: At the 37th annual ESPEN congress in Lisbon, a new Special Interest Group (SIG) in Paediatric Clinical Nutrition was formed. As a first activity of this group, a survey was sent out to all ESPEN members to collect opinions about the objectives of this SIG, explore the interest of ESPEN members in paediatric related nutrition research and clinical practice and to offer to the opportunity for a wider future participation. Methods: A web-based questionnaire survey was distributed to all members of ESPEN via the regular society's newsletter. Results: In total, 123/2828 (4.3%) ESPEN members from 50 countries completed the survey. Fifty-nine of the responders were working in paediatric clinical practice and/or research, 42 in adult medicine, and 20 in both. Fifty-seven (51%) respondents agreed that there is inadequate representation of paediatric nutrition in the current ESPEN activities and 90% of all would like to see more paediatric topics at the ESPEN annual congresses. The development of paediatric clinical practice guidelines should be the scope of this SIG, as indicated by 85 (69%) respondents. Seventy-six (69%) believed that the creation of a Paediatric Clinical Nutrition SIG is likely to impact positively on the society's membership. Conclusions: There is an unmet need for more paediatric related topics and representation with the activities of the ESPEN group. The SIG in Paediatrics aspires to foster multicentre research, development of guidelines and provide a hub for interaction and knowledge exchange

Current clinical trials in paediatrics: report of the ESPEN special interest group in paediatrics

Background &amp; aims: At the 38th annual ESPEN congress in The Hague, the Netherlands, the Special Interest Group (SIG) in Paediatrics presented data about current research activities in the field of paediatric nutrition which are performed worldwide and translated this to future research perspectives. Methods: Extensive search of all registered observational and interventional clinical trials in the database ClinicalTrials.gov using the search terms: children nutrition, paediatrics nutrition and children feeding. Results: A total of 717 studies were found; 173 were duplicates and 114 included adult participants and were therefore excluded. Hence, 430 remained for analysis, of which 69% were randomized controlled trials. The most investigated research topic was nutrition in specific diseases (n = 98), followed by obesity (n = 92), and studies including premature infants (n = 48). The overall median estimated enrolment of children in the trials was 150 children [IQR 50–365]. There were 44 studies in which &gt;1000 participants will be enrolled and six studies with &gt;10,000 participants. Studies including &gt;1000 participants were primarily performed in North America (39%), Africa (27%), and Europe (16%). Conclusions: This SIG report showed that 430 clinical nutrition trials in paediatrics are registered and current research focusses primarily on specific diseases and obesity. The SIG paediatrics encourages future research to invest in well-controlled interventional trials