495 research outputs found

    Short guide to lunar sample information

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    Data pertaining to the collection, processing, and study of lunar samples, and the ways to gain access to that data are described. Data pertaining to the samples includes not only the normally published literature but also NASA and USGS interagency documents, sample processing information, and photography taken from lunar orbit, on the lunar surface, and of samples in the Lunar Receiving Laboratory

    Lunar highland rock types: Their implications for impact induced fractionation

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    The first step in a petrologic study must be a classification based on observed textures and mineralogy. Lunar rocks, may be classified into three major groups: (1) coarse-grained igneous rocks, (2) fine-grained igneous rocks and (3) breccias. Group 1 is interpreted as primitive lunar crustal rocks that display various degrees of crushing and/or annealing. Group 2 is interpreted as volcanic rocks. Group 3 is interpreted as resulting from impacts on the lunar surface and is subdivided on the basis of matrix textures into fragmental breccias, crystalline breccias that have been annealed, and crystalline breccias with igneous matrices. A synthesis of the relevant data concerning lunar highlands polymict breccias from the fields of petrography, chemistry, photogeology, and impact studies compels the prediction that the breccias should have homogeneous matrices from rock to rock within regions of the highlands of limited size where impact mixing has been efficient and extensive

    Introduction to the Apollo collections: Part 2: Lunar breccias

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    Basic petrographic, chemical and age data for a representative suite of lunar breccias are presented for students and potential lunar sample investigators. Emphasis is on sample description and data presentation. Samples are listed, together with a classification scheme based on matrix texture and mineralogy and the nature and abundance of glass present both in the matrix and as clasts. A calculus of the classification scheme, describes the characteristic features of each of the breccia groups. The cratering process which describes the sequence of events immediately following an impact event is discussed, especially the thermal and material transport processes affecting the two major components of lunar breccias (clastic debris and fused material)

    Preliminary data on boulders at station 6, Apollo 17 landing site

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    A cluster of boulders at Station 6 (Apollo 17 landing site) consists of breccias derived from the North Massif. Three preliminary lithologic units were established, on the basis of photogeologic interpretations; all lithologies identified photogeologically were sampled. Breccia clasts and matrices studied petrographically and chemically fall into two groups by modal mineralogy: (1) low-K Fra Mauro or high basalt composition, consisting of 50-60% modal feldspar, approximately 45% orthopyroxene and 1-7% Fe-Ti oxide; (2) clasts consisting of highland basalt composition, consisting of 70% feldspar, 30% orthopyroxene and olivine and a trace of Fe-Ti oxide

    Lunar highland rock types: Their implications for impact-induced fractionation

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    Lunar rocks may be classified into three major groups: (1) coarse-grained igneous rocks, (2) fine-grained igneous rocks, and (3) breccias. Group 1 is interpreted as primitive lunar crustal rocks that display various degrees of crushing and/or annealing. Group 2 is interpreted as volcanic rocks. Group 3 is interpreted as resulting from impacts on the lunar surface and is subdivided on the basis of matrix textures into fragmental breccias, crystalline breccias that have been annealed, and crystalline breccias with igneous matrices. A synthesis of the data concerning lunar highlands polymict breccias compels the prediction that the breccias should have homogeneous matrices from rock to rock within regions of the highlands of limited size where impact mixing has been efficient and extensive. But the returned breccias, even from one landing site, display a wide range in composition. This incompatibility between prediction and observation is a paradox that may be resolved by a process that acts after impact mixing to cause a differentiation of the breccia compositions. Partial melting of the local average crustal composition (as modeled by the average soil composition for each site) and separation of melt and residue in ejecta and/or fall-back blankets are compatible with the reviewed data and may resolve the paradox

    Lunar highland rock types : their implications for impact-induced fractionation

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    Lunar rocks may be classified into three major groups: (1) coarse-grained igneous rocks, (2) fine-grained igneous rocks, and (3) breccias. Group 1 is interpreted as primitive lunar crustal rocks that display various degrees of crushing and/or annealing. Group 2 is interpreted as volcanic rocks. Group 3 is interpreted as resulting from impacts on the lunar surface and is subdivided on the basis of matrix textures into fragmental breccias, crystalline breccias that have been annealed, and crystalline breccias with igneous matrices. A synthesis of the data concerning lunar highlands polymict breccias compels the prediction that the breccias should have homogeneous matrices from rock to rock within regions of the highlands of limited size where impact mixing has been efficient and extensive. But the returned breccias, even from one landing site, display a wide range in composition. This incompatibility between prediction and observation is a paradox that may be resolved by a process that acts after impact mixing to cause a differentiation of the breccia compositions. Partial melting of the local average crustal composition (as modeled by the average soil composition for each site) and separation of melt and residue in ejecta and/or fall-back blankets are compatible with the reviewed data and may resolve the paradox.W. C. Phinney and J. L. Warner, NASA/ Johnson Space Center, Houston, Texas, C. H. Simonds, Lunar Science Institute, Houston, Texa

    Adaptive servo-ventilation for central sleep apnea in heart failure

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    Background Central sleep apnea is associated with poor prognosis and death in patients with heart failure. Adaptive servo-ventilation is a therapy that uses a noninvasive ventilator to treat central sleep apnea by delivering servo-controlled inspiratory pressure support on top of expiratory positive airway pressure. We investigated the effects of adaptive servo-ventilation in patients who had heart failure with reduced ejection fraction and predominantly central sleep apnea. Methods We randomly assigned 1325 patients with a left ventricular ejection fraction of 45% or less, an apnea–hypopnea index (AHI) of 15 or more events (occurrences of apnea or hypopnea) per hour, and a predominance of central events to receive guideline-based medical treatment with adaptive servo-ventilation or guideline-based medical treatment alone (control). The primary end point in the time-to-event analysis was the first event of death from any cause, lifesaving cardiovascular intervention (cardiac transplantation, implantation of a ventricular assist device, resuscitation after sudden cardiac arrest, or appropriate lifesaving shock), or unplanned hospitalization for worsening heart failure. Results In the adaptive servo-ventilation group, the mean AHI at 12 months was 6.6 events per hour. The incidence of the primary end point did not differ significantly between the adaptive servo-ventilation group and the control group (54.1% and 50.8%, respectively; hazard ratio, 1.13; 95% confidence interval [CI], 0.97 to 1.31; P=0.10). All-cause mortality and cardiovascular mortality were significantly higher in the adaptive servo-ventilation group than in the control group (hazard ratio for death from any cause, 1.28; 95% CI, 1.06 to 1.55; P=0.01; and hazard ratio for cardiovascular death, 1.34; 95% CI, 1.09 to 1.65; P=0.006). Conclusions Adaptive servo-ventilation had no significant effect on the primary end point in patients who had heart failure with reduced ejection fraction and predominantly central sleep apnea, but all-cause and cardiovascular mortality were both increased with this therapy. (Funded by ResMed and others; SERVE-HF ClinicalTrials.gov number, NCT00733343. opens in new tab.

    The initial impact of the COVID-19 pandemic on the diagnosis of new cancers at a large pathology laboratory in the public health sector, Western Cape Province, South Africa

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    Background. The COVID-19 pandemic has disrupted cancer diagnostic services. A decline in the number of new cancers being diagnosed over a relatively short term implies a delay in diagnosis and subsequent treatment. This delay is expected to have a negative effect on cancerrelated morbidity and mortality. The impact of the pandemic on the number of new cancer diagnoses in our setting is unknown.Objectives. To assess the impact of COVID-19 on the number of new cancers diagnosed at our institution in the first 3 months following the implementation of lockdown restrictions, by focusing on common non-cutaneous cancers.Methods. A retrospective laboratory-based audit was performed at a large anatomical pathology laboratory in Western Cape Province, South Africa. The numbers of new diagnoses for six common cancers (breast, prostate, cervix, large bowel, oesophagus and stomach) from 1 April 2020 to 30 June 2020 were compared with the corresponding period in 2019.Results. Histopathological diagnoses for the six cancers combined decreased by 193 (–36.3%), from 532 new cases in the 2019 study period to 339 in the corresponding period in 2020. Substantial declines were seen for prostate (–58.2%), oesophageal (–44.1%), breast (–32.9%), gastric (–32.6%) and colorectal cancer (–29.2%). The smallest decline was seen in cervical cancer (–7%). New breast cancers diagnosed by cytopathology declined by 61.1%.Conclusions. The first wave of the COVID-19 pandemic and the associated response resulted in a substantial decline in the number of new cancer diagnoses, implying a delay in diagnosis. Cancer-related morbidity and mortality is expected to rise as a result, with the greatest increase in mortality expected from breast and colorectal cancer

    Development and validation of a novel non-contact monitor of nocturnal respiration for identifying sleep-disordered breathing in patients with heart failure

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    © 2016 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology. Aims: At least 50% of patients with heart failure (HF) may have sleep-disordered breathing (SDB). Overnight in-hospital polysomnography (PSG) is considered the gold standard for diagnosis, but a lack of access to such testing contributes to under-diagnosis of SDB. Therefore, there is a need for simple and reliable validated methods to aid diagnosis in patients with HF. The aim of this study was to investigate the accuracy of a non-contact type IV screening device, SleepMinderTM (SM), compared with in-hospital PSG for detecting SDB in patients with HF. Methods and results: The study included 75 adult patients with systolic HF and suspected SDB who underwent simultaneous PSG and SM recordings. An algorithm was developed from the SM signals, using digital signal processing and pattern recognition techniques to calculate the SM apnoea-hypopnoea index (AHI). This was then compared with expert-scored PSGAHI. The SM algorithm had 70% sensitivity and 89% specificity for identifying patients with clinically significant SDB (AHI ≥ 15/h). At this threshold, it had a positive likelihood ratio of 6.3 and a negative likelihood ratio of 0.16. The overall accuracy of the SMAHI algorithm was 85.8% as shown by the area under a receiver operator characteristic curve. The mean AHI with SM was 3.8/h (95% confidence interval 0.5–7.1) lower than that with PSG. Conclusions: The accuracy of the non-contact type IV screening device SM is good for clinically significant SDB in patients with systolic HF and could be considered as a simple first step in the diagnostic pathway

    Introducing a core curriculum for respiratory sleep practitioners

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    The background and purpose of the HERMES (Harmonising Education in Respiratory Medicine for European Specialists) initiative has been discussed at length in previous articles [1-3]. This article aims to provide more detailed and specific insight into the process and methodology of the Sleep HERMES Task Force in developing a core curriculum in respiratory sleep medicine
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