96 research outputs found

    Mission Planning for Close-Proximity Satellites

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    Given an initial orbit and a set of other orbits of interest, the lowest change in velocity path between them is of high value. Software was developed to visualize the change in velocity required from a user defined window of burn to a user defined window of intercept. The time between burn and intercept is unrestricted. Multiple intercepts require searching an n! solution space, research then is focused on ways to pick optimal choices without fully calculating out the cost of doing all possible combinations. Some code was translated from BASIC and the rest was newly developed in MATLAB. The code was validated using orbits with known intercept solutions

    Day 6 estradiol level predicts cycle cancellation among poor responder patients undergoing in vitro fertilization - Embryo transfer cycles using a gonadotropin-releasing hormone agonist flare regimen

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    Purpose: To compare two GnRHa flare protocols among poor responders undergoing IVF-ET and to evaluate if a Day 6 estradiol level can predict outcome. Methods: Retrospective analyses of GnRHa flare IVF cycles among poor responders. Group A ("miniflare," N = 36) 40 mug GnRHa s.c. b.i.d. from Day 3; Group B ("standard flare," N = 24) 1 mg GnRHa on Days 2-3; 0.5 mg GnRHa from Day 4. ROC analysis was performed to find a Day 6 estradiol value that is predictive of cycle outcome. Results: With the standard flare, patients required less gonadotropins and tended to have fewer cancellations and higher pregnancy rates. A Day 6 estradiol level less than or equal to75 pg/mL was predictive of cycle cancellation, but not of pregnancy outcome. Conclusions: Standard GnRHa flare offers some advantages over the miniflare. Day 6 estradiol less than or equal to75 pg/mL is predictive of cycle cancellation. When the estradiol level is low on Day 6 (no flare), early cancellation should be considered

    Hypothalamic-pituitary suppression with oral contraceptive pills does not improve outcome in poor responder patients undergoing in vitro fertilization-embryo transfer cycles

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    Purpose: To evaluate and compare the use of OCP with GnRHa for hypothalamic Pituitary suppression in poor responder IVF patients.Methods: Retrospective analysis of IVF-ET cycles of poor responders. Hypothalamic-pituitary suppression with OCP (Group I, n = 29) or GnRHa (Group II, n = 52), followed by stimulation with gonadotropin, oocyte retrieval, and embryo transfer. Baseline characteristics and cycle outcomes were compared.Results: 73 women underwent 81 cycles from 1/1/1999 to 1/1/2000. Baseline characteristics were similar. 31/81 (38%) cycles were cancelled (Group I, 14/29 (48%) vs. Group II, 17/52 (33%), NS). Cycle outcomes including amount of gonadotropin, number of eggs retrieved, number of embryos transferred, and embryo quality were similar. Patients in Group I required fewer days of stimulation to reach oocyte retrieval. Pregnancy outcomes were similar in the two groups.Conclusion: Our retrospective analysis revealed no improvement in IVF cycle outcomes in poor responders who received OCPs to achieve hypothalamic-pituitary suppression instead of GnRHa

    Atmospheric trace metal concentrations, solubility and deposition fluxes in remote marine air over the south-east Atlantic

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    Total and soluble trace metal concentrations were determined in atmospheric aerosol and rainwater samples collected during seven cruises in the south-east Atlantic. Back trajectories indicated the samples all represented remote marine air masses, consistent with climatological expectations. Aerosol trace metal loadings were similar to previous measurements in clean, marine air masses. Median total Fe, Al, Mn, V, Co and Zn concentrations were 206, 346, 5, 3, 0.7 and 11 pmol m-3 respectively. Solubility was operationally defined as the fraction extractable using a pH4.7 ammonium acetate leach. Median soluble Fe, Al, Mn, V, Co, Zn, Cu, Ni, Cd and Pb concentrations were 6, 55, 1, 0.7, 0.06, 24, 2, 1, 0.05 and 0.3 pmol m-3 respectively. Large ranges in fractional solubility were observed for all elements except Co; median solubility values for Fe, Al and Mn were below 20% while the median for Zn was 74%. Volume weighted mean rainwater concentrations were 704, 792, 32, 10, 3, 686, 25, 0.02, 0.3 and 10 nmol L-1 for Fe, Al, Mn, V, Co, Zn, Cu, Ni, Cd and Pb respectively (n = 6). Wet deposition fluxes calculated from these values suggest rain makes a significant contribution to total deposition in the study area for all elements except perhaps Ni

    Psychological experience and coping strategies of patients in the Northeast US delaying care for infertility during the COVID-19 pandemic.

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    BACKGROUND: On March 17, 2020 an expert ASRM task force recommended the temporary suspension of new, non-urgent fertility treatments during an ongoing world-wide pandemic of Covid-19. We surveyed at the time of resumption of fertility care the psychological experience and coping strategies of patients pausing their care due to Covid-19 and examined which factors were associated and predictive of resilience, anxiety, stress and hopefulness. METHODS: Cross sectional cohort patient survey using an anonymous, self-reported, single time, web-based, HIPPA compliant platform (REDCap). Survey sampled two Northeast academic fertility practices (Yale Medicine Fertility Center in CT and Montefiore\u27s Institute for Reproductive Medicine and Health in NY). Data from multiple choice and open response questions collected demographic, reproductive history, experience and attitudes about Covid-19, prior infertility treatment, sense of hopefulness and stress, coping strategies for mitigating stress and two validated psychological surveys to assess anxiety (six-item short-form State Trait Anxiety Inventory (STAl-6)) and resilience (10-item Connor-Davidson Resilience Scale, (CD-RISC-10). RESULTS: Seven hundred thirty-four patients were sent invitations to participate. Two hundred fourteen of 734 (29.2%) completed the survey. Patients reported their fertility journey had been delayed a mean of 10 weeks while 60% had been actively trying to conceive \u3e 1.5 years. The top 5 ranked coping skills from a choice of 19 were establishing a daily routine, going outside regularly, exercising, maintaining social connection via phone, social media or Zoom and continuing to work. Having a history of anxiety (p \u3c 0.0001) and having received oral medication as prior infertility treatment (p \u3c 0.0001) were associated with lower resilience. Increased hopefulness about having a child at the time of completing the survey (p \u3c 0.0001) and higher resilience scores (p \u3c 0.0001) were associated with decreased anxiety. Higher reported stress scores (p \u3c 0.0001) were associated with increased anxiety. Multiple multivariate regression showed being non-Hispanic black (p = 0.035) to be predictive of more resilience while variables predictive of less resilience were being a full-time homemaker (p = 0.03), having received oral medication as prior infertility treatment (p = 0.003) and having higher scores on the STAI-6 (\u3c 0.0001). CONCLUSIONS: Prior to and in anticipation of further pauses in treatment the clinical staff should consider pretreatment screening for psychological distress and provide referral sources. In addition, utilization of a patient centered approach to care should be employed

    The structure of Chariklo's rings from stellar occultations

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    Two narrow and dense rings (called C1R and C2R) were discovered around the Centaur object (10199) Chariklo during a stellar occultation observed on 2013 June 3. Following this discovery, we planned observations of several occultations by Chariklo's system in order to better characterize the physical properties of the ring and main body. Here, we use 12 successful occulations by Chariklo observed between 2014 and 2016. They provide ring profiles (physical width, opacity, edge structure) and constraints on the radii and pole position. Our new observations are currently consistent with the circular ring solution and pole position, to within the ±3.3\pm 3.3 km formal uncertainty for the ring radii derived by Braga-Ribas et al. The six resolved C1R profiles reveal significant width variations from ∼5\sim 5 to 7.5 km. The width of the fainter ring C2R is less constrained, and may vary between 0.1 and 1 km. The inner and outer edges of C1R are consistent with infinitely sharp boundaries, with typical upper limits of one kilometer for the transition zone between the ring and empty space. No constraint on the sharpness of C2R's edges is available. A 1σ\sigma upper limit of ∼20\sim 20 m is derived for the equivalent width of narrow (physical width <4 km) rings up to distances of 12,000 km, counted in the ring plane

    Using Satellite Tracking to Optimize Protection of Long-Lived Marine Species: Olive Ridley Sea Turtle Conservation in Central Africa

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    Tractable conservation measures for long-lived species require the intersection between protection of biologically relevant life history stages and a socioeconomically feasible setting. To protect breeding adults, we require knowledge of animal movements, how movement relates to political boundaries, and our confidence in spatial analyses of movement. We used satellite tracking and a switching state-space model to determine the internesting movements of olive ridley sea turtles (Lepidochelys olivacea) (n = 18) in Central Africa during two breeding seasons (2007-08, 2008-09). These movements were analyzed in relation to current park boundaries and a proposed transboundary park between Gabon and the Republic of Congo, both created to reduce unintentional bycatch of sea turtles in marine fisheries. We additionally determined confidence intervals surrounding home range calculations. Turtles remained largely within a 30 km radius from the original nesting site before departing for distant foraging grounds. Only 44.6 percent of high-density areas were found within the current park but the proposed transboundary park would incorporate 97.6 percent of high-density areas. Though tagged individuals originated in Gabon, turtles were found in Congolese waters during greater than half of the internesting period (53.7 percent), highlighting the need for international cooperation and offering scientific support for a proposed transboundary park. This is the first comprehensive study on the internesting movements of solitary nesting olive ridley sea turtles, and it suggests the opportunity for tractable conservation measures for female nesting olive ridleys at this and other solitary nesting sites around the world. We draw from our results a framework for cost-effective protection of long-lived species using satellite telemetry as a primary tool

    Homeopathy – what are the active ingredients? An exploratory study using the UK Medical Research Council's framework for the evaluation of complex interventions

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    BACKGROUND: Research in homeopathy has traditionally addressed itself to defining the effectiveness of homeopathic potencies in comparison to placebo medication. There is now increasing awareness that the homeopathic consultation is in itself a therapeutic intervention working independently or synergistically with the prescribed remedy. Our objective was to identify and evalute potential "active ingredients" of the homeopathic approach as a whole, in a prospective formal case series, which draws on actual consultation data, and is based on the MRC framework for the evaluation of complex interventions. METHODS: Following on from a theoretical review of how homeopathic care might mediate its effects, 18 patients were prospectively recruited to a case series based at Bristol Homeopathic Hospital. Patients, who lived with one of three index conditions, were interviewed before and after a five visit "package of care". All consultations were recorded and transcribed verbatim. Additional data, including generic and condition-specific questionnaires, artwork and "significant other" reports were collected. Textual data was subject to thematic analysis and triangulated with other sources. RESULTS: We judged that around one third of patients had experienced a major improvement in their health over the study period, a third had some improvement and a third had no improvement. Putative active ingredients included the patients' "openness to the mind-body connection", consultational empathy, in-depth enquiry into bodily complaints, disclosure, the remedy matching process and, potentially, the homeopathic remedies themselves. CONCLUSION: This study has has identified, using primary consultation and other data, a range of factors that might account for the effectiveness of homeopathic care. Some of these, such as empathy, are non-specific. Others, such as the remedy matching process, are specific to homeopathy. These findings counsel against the use of placebo-controlled RCT designs in which both arms would potentially be receiving specific active ingredients. Future research in homeopathy should focus on pragmatic trials and seek to confirm or refute the therapeutic role of constructs such as patient "openness", disclosure and homeopathicity

    Analysis of FOXP3+ Regulatory T Cells That Display Apparent Viral Antigen Specificity during Chronic Hepatitis C Virus Infection

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    We reported previously that a proportion of natural CD25+ cells isolated from the PBMC of HCV patients can further upregulate CD25 expression in response to HCV peptide stimulation in vitro, and proposed that virus-specific regulatory T cells (Treg) were primed and expanded during the disease. Here we describe epigenetic analysis of the FOXP3 locus in HCV-responsive natural CD25+ cells and show that these cells are not activated conventional T cells expressing FOXP3, but hard-wired Treg with a stable FOXP3 phenotype and function. Of ∼46,000 genes analyzed in genome wide transcription profiling, about 1% were differentially expressed between HCV-responsive Treg, HCV-non-responsive natural CD25+ cells and conventional T cells. Expression profiles, including cell death, activation, proliferation and transcriptional regulation, suggest a survival advantage of HCV-responsive Treg over the other cell populations. Since no Treg-specific activation marker is known, we tested 97 NS3-derived peptides for their ability to elicit CD25 response (assuming it is a surrogate marker), accompanied by high resolution HLA typing of the patients. Some reactive peptides overlapped with previously described effector T cell epitopes. Our data offers new insights into HCV immune evasion and tolerance, and highlights the non-self specific nature of Treg during infection

    Building sensory receptors on the tongue

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    Neurotrophins, neurotrophin receptors and sensory neurons are required for the development of lingual sense organs. For example, neurotrophin 3 sustains lingual somatosensory neurons. In the traditional view, sensory axons will terminate where neurotrophin expression is most pronounced. Yet, lingual somatosensory axons characteristically terminate in each filiform papilla and in each somatosensory prominence within a cluster of cells expressing the p75 neurotrophin receptor (p75NTR), rather than terminating among the adjacent cells that secrete neurotrophin 3. The p75NTR on special specialized clusters of epithelial cells may promote axonal arborization in vivo since its over-expression by fibroblasts enhances neurite outgrowth from overlying somatosensory neurons in vitro . Two classical observations have implicated gustatory neurons in the development and maintenance of mammalian taste buds—the early arrival times of embryonic innervation and the loss of taste buds after their denervation in adults. In the modern era more than a dozen experimental studies have used early denervation or neurotrophin gene mutations to evaluate mammalian gustatory organ development. Necessary for taste organ development, brain-derived neurotrophic factor sustains developing gustatory neurons. The cardinal conclusion is readily summarized: taste buds in the palate and tongue are induced by innervation. Taste buds are unstable: the death and birth of taste receptor cells relentlessly remodels synaptic connections. As receptor cells turn over, the sensory code for taste quality is probably stabilized by selective synapse formation between each type of gustatory axon and its matching taste receptor cell. We anticipate important new discoveries of molecular interactions among the epithelium, the underlying mesenchyme and gustatory innervation that build the gustatory papillae, their specialized epithelial cells, and the resulting taste buds.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47466/1/11068_2005_Article_3332.pd
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