Alternate assembly sequence databook for the Tier 2 Bus-1 option of the International Space Station

The JSC International Space Station program office requested that SSB prepare a databook to document the alternate space station assembly sequence known as Tier 2, which assumes that the Russian participation has been eliminated and that the functions that were supplied by the Russians (propulsion, resupply, initial attitude control, communications, etc.) are now supplied by the U.S. Tier 2 utilizes the Lockheed Bus-l to replace much of the missing Russian functionality. The space station at each stage of its buildup during the Tier 2 assembly sequence is characterized in terms of of properties, functionality, resource balances, operations, logistics, attitude control, microgravity environment and propellant usage. The assembly sequence as analyzed was defined by JSC as a first iteration, with subsequent iterations required to address some of the issues that the analysis in this databook identified. Several significant issues were identified, including: less than desirable orbit lifetimes, shortage of EVA, large flight attitudes, poor microgravity environments, and reboost propellant shortages. Many of these issues can be resolved but at the cost of possible baseline modifications and revisions in the proposed Tier 2 assembly sequence

Characterization of Cell Division in the Tissues of the Calanoid Copepod, Neocalanus flemingeri from Diapause through Early Oogenesis

Unlike most calanoid copepods, females of the diapausing copepod, Neocalanus flemingeri (Miller, 1988) fuel oogenesis entirely through stored energy. Due to the reliance on stored energy, N. flemingeri females manage their internal lipid stores to maximize oocyte production which differs from the reproductive program of most calanoids that couple food availability with oogenesis. In this study, both lipid content and cell division within the reproductive structures in females were examined as diapause was terminated and oogenesis began. In June and September 2019, diapausing females were collected from depth in Prince William Sound, Alaska. Incubation experiments in 5-Ethynyl-2´-deoxyuridine (EdU) were conducted to quantify and pinpoint the location of cell division within the body from diapause through early oogenesis. Imaging of EdU-treated females using confocal microscopy revealed evidence of cell division in the ovary within 24 hours after collection. Both oogonia and oocytes incorporated EdU based on the location of cells in the posterior end of the ovary. Dividing cells in the ovary peaked in number at 72 hours, remained high over two weeks, and decreased thereafter with no staining detected at four weeks after collection. Thus, the production of new oocytes stopped two to four weeks before females release their first clutch of eggs. The pattern of cell division in the ovary parallels the up- and down-regulation of early germline development genes reported in an earlier transcriptomics study. These results suggest that oogenesis is sequential in N. flemingeri which synchronizes egg maturation, unlike other calanoid copepods where most oocyte stages are observed concurrently within the ovary. The magnitude of cell division in the ovary of individual females were compared with their respective total lipid contents and prosome lengths. Numbers of dividing cells in the ovaries were positively correlated with both prosome length and lipid content, suggesting that total fecundity is higher in copepods with longer prosome lengths and more lipid. In this study, duration of the period of active cell division appeared to be similar in all females independent of prosome size or lipid content. Understanding the internal physiological process of reproduction in lipid-rich copepods like N. flemingeri is an important step in knowing how and to what magnitude egg production can be affected by climate change. This is the first study that tracked cell division in post-diapause N. flemingeri. This capital breeder meters its energy sources by varying the number of dividing cells and limiting cell division in the ovary to the first three to four weeks post-diapause. As waters continue to warm, predictions of shorter diapause lengths, and both smaller lipid reserves and prosome lengths have been hypothesized. Negative impacts on egg production in this species could lead to a decrease in population numbers and thus a decrease in a vital food source for many birds and fishes

A NEW GENUS OF APHIDÆ

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Letter from John J. Monell to Nehemiah Denton, 1839-08-22

This item is from the Nehemiah Denton Papers. The collection includes letters and other materials of this Brooklyn, New York resident with business interests in Mobile, Alabama. Aside from an extensive business correspondence, it includes detailed descriptions of Mobile's antebellum social life, and accounts of yellow fever epidemics and fires

Letter from John J. Monell to Nehemiah Denton, 1839-08-23

This item is from the Nehemiah Denton Papers. The collection includes letters and other materials of this Brooklyn, New York resident with business interests in Mobile, Alabama. Aside from an extensive business correspondence, it includes detailed descriptions of Mobile's antebellum social life, and accounts of yellow fever epidemics and fires

Satellite Systems Design/Simulation Environment: A Systems Approach to Pre-Phase A Design

A toolset for the rapid development of small satellite systems has been created. The objective of this tool is to support the definition of spacecraft mission concepts to satisfy a given set of mission and instrument requirements. The objective of this report is to provide an introduction to understanding and using the SMALLSAT Model. SMALLSAT is a computer-aided Phase A design and technology evaluation tool for small satellites. SMALLSAT enables satellite designers, mission planners, and technology program managers to observe the likely consequences of their decisions in terms of satellite configuration, non-recurring and recurring cost, and mission life cycle costs and availability statistics. It was developed by Princeton Synergetic, Inc. and User Systems, Inc. as a revision of the previous TECHSAT Phase A design tool, which modeled medium-sized Earth observation satellites. Both TECHSAT and SMALLSAT were developed for NASA

Baja tasa de infarto cerebral, infarto de miocardio y muerte vascular con el diagnóstico y tratamiento etiológico rápido del ataque isquémico transitorio

Resumen: Introducción: El riesgo de infarto cerebral dentro de los primeros 90 días tras un ataque isquémico transitorio (AIT) se estima entre un 8-20%. Existe escaso consenso sobre cuál es la estrategia diagnóstica más eficaz. Nuestro objetivo fue evaluar del beneficio del estudio precoz con ecocardiografía transtorácica (ETT) y ultrasonografía carotídea y transcraneal (DTSA/TC) en los pacientes con AIT. Métodos: Evaluamos de forma prospectiva todos los pacientes con AIT atendidos en urgencias durante 24 meses. Recogimos variables demográficas, factores de riesgo vascular y escala ABCD2. La etiología del AIT fue clasificada según criterios TOAST. En todos los pacientes se realizó el estudio vascular precoz (< 72 h) con ETT y DTSA/TC. Los objetivos primarios fueron la recurrencia vascular cerebral, infarto de miocardio (IAM) o muerte vascular durante el primer año. Resultados: Evaluamos 92 pacientes con una edad media de 68,3 ± 13 años y el 61% fueron hombres. La media de la escala ABCD2 fue de 3 puntos (≥ 5 en un 30%). La distribución etiológica fue la siguiente: aterotrombótico de gran vaso 12%; cardioembólico 30%; pequeño vaso 10%; indeterminado 40% e inhabitual 8%. Los hallazgos de la ETT cambiaron el tratamiento en 6 pacientes (6,5%) con exploración física y ECG normal. Al año de seguimiento 3 pacientes (3,2%) sufrieron un infarto cerebral, uno (1%) un IAM y no detectamos ninguna muerte vascular. Conclusiones: El estudio etiológico precoz en los pacientes con AIT y la detección de pacientes con cardiopatía silente puede haber contribuido a la baja tasa de recurrencia vascular. Abstract: Introduction: The 90-day risk of cerebral infarction in patients with transient ischaemic attack (TIA) is estimated at between 8% and 20%. There is little consensus as to which diagnostic strategy is most effective. This study evaluates the benefits of early transthoracic echocardiography (TTE) with carotid and transcranial Doppler ultrasound in patients with TIA. Methods: Prospective study of patients with TIA in an emergency department setting. Demographic data, vascular risk factors, and ABCD2 score were analysed. TIA aetiology was classified according to TOAST criteria. All patients underwent early vascular studies (< 72 hours), including TTE, carotid ultrasound, and transcranial Doppler. Primary endpoints were recurrence of stroke or TIA, myocardial infarction (MI), or vascular death during the first year. Results: We evaluated 92 patients enrolled over 24 months. Mean age was 68.3 ± 13 years and 61% were male. The mean ABCD2 score was 3 points (≥ 5 in 30%). The distribution of TIA subtypes was as follows: 12% large-artery atherosclerosis; 30% cardioembolism; 10% small-vessel occlusion; 40% undetermined cause; and 8% rare causes. Findings from the early TTE led to a change in treatment strategy in 6 patients (6.5%) who displayed normal physical examination and ECG findings. At one year of follow-up, 3 patients had experienced stroke (3.2%) and 1 patient experienced MI (1%); no vascular deaths were identified. Conclusions: In our TIA patients, early vascular study and detecting patients with silent cardiomyopathy may have contributed to the low rate of vascular disease recurrence. Palabras clave: Infarto cerebral, Ataque isquémico transitorio, Ecocardiografía, Keywords: Stroke, Transient ischaemic attack, Echocardiograph