1,113 research outputs found

    Randomizer for High Data Rates

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    NASA as well as a number of other space agencies now recognize that the current recommended CCSDS randomizer used for telemetry (TM) is too short. When multiple applications of the PN8 Maximal Length Sequence (MLS) are required in order to fully cover a channel access data unit (CADU), spectral problems in the form of elevated spurious discretes (spurs) appear. Originally the randomizer was called a bit transition generator (BTG) precisely because it was thought that its primary value was to insure sufficient bit transitions to allow the bit/symbol synchronizer to lock and remain locked. We, NASA, have shown that the old BTG concept is a limited view of the real value of the randomizer sequence and that the randomizer also aids in signal acquisition as well as minimizing the potential for false decoder lock. Under the guidelines we considered here there are multiple maximal length sequences under GF(2) which appear attractive in this application. Although there may be mitigating reasons why another MLS sequence could be selected, one sequence in particular possesses a combination of desired properties which offsets it from the others

    Understanding early inhibitory development : distinguishing two ways that children use inhibitory control

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    Inhibitory control is the capacity to suppress inappropriate responses. It is regarded as a unitary construct, central to executive function and effortful control, as well as many aspects of child development. There are, nevertheless, significant gaps in our understanding of inhibition’s early development, and several robust findings that remain hard to explain. These findings are outlined, and a new perspective on inhibitory control presented, which explains them by distinguishing between two ways that inhibitory control is used. According to the ‘strength/endurance account’, responses which are highly prepotent tax inhibitory strength; whereas, those which remain active for a long time tax inhibitory endurance. The review considers when and how these aspects of inhibition mature, before discussing their impact on development

    Landsat Data Continuity Mission (LDCM) - Optimizing X-Band Usage

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    The NASA version of the low-density parity check (LDPC) 7/8-rate code, shortened to the dimensions of (8160, 7136), has been implemented as the forward error correction (FEC) schema for the Landsat Data Continuity Mission (LDCM). This is the first flight application of this code. In order to place a 440 Msps link within the 375 MHz wide X band we found it necessary to heavily bandpass filter the satellite transmitter output . Despite the significant amplitude and phase distortions that accompanied the spectral truncation, the mission required BER is maintained at < 10(exp -12) with less than 2 dB of implementation loss. We utilized a band-pass filter designed ostensibly to replicate the link distortions to demonstrate link design viability. The same filter was then used to optimize the adaptive equalizer in the receiver employed at the terminus of the downlink. The excellent results we obtained could be directly attributed to the implementation of the LDPC code and the amplitude and phase compensation provided in the receiver. Similar results were obtained with receivers from several vendors

    Use of archival versus newly collected tumor samples for assessing PD-L1 expression and overall survival : an updated analysis of KEYNOTE-010 trial

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    Background: In KEYNOTE-010, pembrolizumab versus docetaxel improved overall survival (OS) in patients with programmed death-1 protein (PD)-L1-positive advanced non-small-cell lung cancer (NSCLC). A prespecified exploratory analysis compared outcomes in patients based on PD-L1 expression in archival versus newly collected tumor samples using recently updated survival data. Patients and methods: PD-L1 was assessed centrally by immunohistochemistry (22C3 antibody) in archival or newly collected tumor samples. Patients received pembrolizumab 2 or 10 mg/kg Q3W or docetaxel 75 mg/m2 Q3W for 24 months or until progression/intolerable toxicity/other reason. Response was assessed by RECIST v1.1 every 9 weeks, survival every 2 months. Primary end points were OS and progression-free survival (PFS) in tumor proportion score (TPS) 50% and 1%; pembrolizumab doses were pooled in this analysis. Results: At date cut-off of 24 March 2017, median follow-up was 31 months (range 23-41) representing 18 additional months of follow-up from the primary analysis. Pembrolizumab versus docetaxel continued to improve OS in patients with previously treated, PD-L1-expressing advanced NSCLC; hazard ratio (HR) was 0.66 [95% confidence interval (CI): 0.57, 0.77]. Of 1033 patients analyzed, 455(44%) were enrolled based on archival samples and 578 (56%) on newly collected tumor samples. Approximately 40% of archival samples and 45% of newly collected tumor samples were PD-L1 TPS 50%. For TPS 50%, the OS HRs were 0.64 (95% CI: 0.45, 0.91) and 0.40 (95% CI: 0.28, 0.56) for archival and newly collected samples, respectively. In patients with TPS 1%, OS HRs were 0.74 (95% CI: 0.59, 0.93) and 0.59 (95% CI: 0.48, 0.73) for archival and newly collected samples, respectively. In TPS 50%, PFS HRs were similar across archival [0.63 (95% CI: 0.45, 0.89)] and newly collected samples [0.53 (95% CI: 0.38, 0.72)]. In patients with TPS 1%, PFS HRs were similar across archival [0.82 (95% CI: 0.66, 1.02)] and newly collected samples [0.83 (95% CI: 0.68, 1.02)]. Conclusion: Pembrolizumab continued to improve OS over docetaxel in intention to treat population and in subsets of patients with newly collected and archival samples

    Cumulative childhood trauma and complex psychiatric symptoms in pregnant women and expecting men

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    Background: Women and men having been exposed to childhood trauma would be at high risk of various mental health symptoms while awaiting a child. This study aimed to evaluate the association between cumulative childhood trauma and the accumulation of symptoms belonging to different psychiatric problems in pregnant women and expecting men. Methods: We first examined prevalence rates of childhood trauma across our samples of 2853 pregnant women and 561 expecting men from the community. Second, we evaluated the association between cumulative childhood trauma and symptom complexity (i.e., the simultaneous presentation of symptoms belonging to multiple psychiatric problems) using subsamples of 1779 pregnant women and 118 expecting men. Participants completed self-reported measures of trauma (Childhood Trauma Questionnaire) and psychiatric symptoms (PTSD Checklist for DSM-5; Kessler Psychological Distress Scale; State-Trait Anger Expression Inventory-2; Self and Interpersonal Functioning Scale). Results: Trauma was more frequent in pregnant women than in expecting men and in participants reporting sociodemographic risk factors than in those not reporting any. A dose-response relationship was observed between the number of different traumas reported by pregnant women and expecting men and the complexity of their psychiatric symptoms, even when controlling for the variance explained by other risk factors. Women having been exposed to cumulative childhood trauma were 4.95 times more at risk of presenting comorbid psychiatric problems during pregnancy than non-exposed women. Conclusions: Childhood trauma is frequent in the general population of pregnant women and expecting men and is associated with symptom complexity during the antenatal period. These findings call for delivering and evaluating innovative trauma-informed antenatal programs to support mental health and adaptation to parenthood in adults having been exposed to childhood trauma. © 2021, The Author(s)

    A deeper look at the association between childhood maltreatment and reflective functioning

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    Childhood maltreatment is theorized as impeding the development of reflective functioning (RF; ability to perceive and interpret oneself and others in terms of mental states). However, previous research typically failed to support this association or yielded small sized and mixed associations. This study aims to provide a deeper look at the association between childhood maltreatment and RF by characterizing two non-mentalizing categories. One-hundred-and-sixteen pregnant women (mean age = 27.62, SD = 4.52) from the community (48.3% with a university degree, 96.5% in a relationship with the other parent) retrospectively reported on childhood abuse and neglect using the Childhood Trauma Questionnaire. They also participated in the Adult Attachment Interview subsequently coded using the Reflective Functioning Scale. Participants with poor to low RF were allocated to one of two groups (disavowal-distancing or distorted-inconsistent) using indicators provided in the RF Scale. No association was found between childhood maltreatment and overall RF when controlling for education level. A multinomial logistic regression revealed that childhood maltreatment was strongly predictive of a disrupted, over-analytical and inconsistent reflection about mental states but not of a tendency to discourse little about mental states. This tendency was rather only predicted by education level. Findings suggest that childhood maltreatment would lead to specific impairments in RF and that not considering how individuals fail to mentalize about attachment relationships may mask strong associations between RF and its determinants and correlates, including childhood maltreatment

    A systematic practice review: providing palliative care for people with Parkinson's disease and their caregivers

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    Background: People with Parkinson’s disease has significant and increasing physical, psychosocial and spiritual needs, as well as problems with coordination and continuity of care. Despite the benefits that palliative care could offer, there is no consensus on how it should be delivered. Aim: The aim of this study is to provide a pragmatic overview of the evidence to make clinical recommendations to improve palliative care for people with Parkinson’s disease and their caregivers. Design:A systematic review method was adopted to determine the strength of evidence, supported by feedback from an expert panel, to generate the ‘do’, ‘do not do’ and ‘do not know’ recommendations for palliative care. Data sources: Searches were conducted via OVID to access CINAHL, MEDLINE, EMBASE and the Cochrane Library from 01/01/2006 to 31/05/2021. An additional search was conducted in December 2022. The search was limited to articles that included empirical studies of approaches to enabling palliative care. Results: A total of 62 studies met inclusion criteria. There is evidence that education about palliative care and movement disorders is essential. palliative care should be multi-disciplinary, individualised and coordinated. Proactive involvement and support of caregivers throughout the illness is recommended. Limited data provide referral indicators for palliative care integration. Discussions about advance care planning should be held early.Conclusions: Consideration of palliative care integration based on symptom burden and personal preferences, coordination and continuity of care are needed to maintain the quality of life of people with Parkinson’s disease and their caregivers.info:eu-repo/semantics/publishedVersio
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