Measurements of an ionizable constituent of low ionosphere using a Lyman-alpha source and blunt probe

Ionizable constituent density measurement of D region using Lyman-alpha source and blunt prob

On-board processing satellite network architecture and control study

The market for telecommunications services needs to be segmented into user classes having similar transmission requirements and hence similar network architectures. Use of the following transmission architecture was considered: satellite switched TDMA; TDMA up, TDM down; scanning (hopping) beam TDMA; FDMA up, TDM down; satellite switched MF/TDMA; and switching Hub earth stations with double hop transmission. A candidate network architecture will be selected that: comprises multiple access subnetworks optimized for each user; interconnects the subnetworks by means of a baseband processor; and optimizes the marriage of interconnection and access techniques. An overall network control architecture will be provided that will serve the needs of the baseband and satellite switched RF interconnected subnetworks. The results of the studies shall be used to identify elements of network architecture and control that require the greatest degree of technology development to realize an operational system. This will be specified in terms of: requirements of the enabling technology; difference from the current available technology; and estimate of the development requirements needed to achieve an operational system. The results obtained for each of these tasks are presented

On-board processing satellite network architecture and control study

For satellites to remain a vital part of future national and international communications, system concepts that use their inherent advantages to the fullest must be created. Network architectures that take maximum advantage of satellites equipped with onboard processing are explored. Satellite generations must accommodate various services for which satellites constitute the preferred vehicle of delivery. Such services tend to be those that are widely dispersed and present thin to medium loads to the system. Typical systems considered are thin and medium route telephony, maritime, land and aeronautical radio, VSAT data, low bit rate video teleconferencing, and high bit rate broadcast of high definition video. Delivery of services by TDMA and FDMA multiplexing techniques and combinations of the two for individual and mixed service types are studied. The possibilities offered by onboard circuit switched and packet switched architectures are examined and the results strongly support a preference for the latter. A detailed design architecture encompassing the onboard packet switch and its control, the related demand assigned TDMA burst structures, and destination packet protocols for routing traffic are presented. Fundamental onboard hardware requirements comprising speed, memory size, chip count, and power are estimated. The study concludes with identification of key enabling technologies and identifies a plan to develop a POC model

COMSAT Laboratories' on-board baseband switch development

Work performed at COMSAT Laboratories to develop a prototype on-board baseband switch is summarized. The switch design is modular to accommodate different service types, and the architecture features a high-speed optical ring operating at 1 Gbit/s to route input (up-link) channels to output (down-link) channels. The switch is inherently a packet switch, but can process either circuit-switched or packet-switched traffic. If the traffic arrives at the satellite in a circuit-switched mode, the input processor packetizes it and passes it on to the switch. The main advantage of the packet approach lies in its simplified control structure. Details of the switch architecture and design, and the status of its implementation, are presented

Communications platform payload definition study, executive summary

Large geostationary communications platforms have been investigated in a number of studies since 1974 as a possible means to more effectively utilize the geostationary orbital arc and electromagnetic spectrum and to reduce overall satellite communications system costs. This NASA Lewis sponsored study addresses the commercial feasibility of various communications platform payload concepts circa 1998. It defines promising payload concepts, estimates recurring costs and identifies critical technologies needed to permit eventual commercialization. Ten communications service aggregation scenarios describing potential groupings of services were developed for a range of conditions. Payload concepts were defined for four of these scenarios: (1) Land Mobile Satellite Service (LMSS), meet 100% of CONUS plus Canada demand with a single platform; (2) Fixed Satellite Service (FSS) (Trunking + Customer Premises Service (CPS), meet 20% of CONUS demands; (3) FSS (Trunking + video distribution), 10 to 13% of CONUS demand; and (4) FSS (20% of demand) + Inter Satellite Links (ISL) + TDRSS/TDAS Data Distribution

Hook3 is a scaffold for the opposite-polarity microtubule-based motors cytoplasmic dynein-1 and KIF1C.

The unidirectional and opposite-polarity microtubule-based motors, dynein and kinesin, drive long-distance intracellular cargo transport. Cellular observations suggest that opposite-polarity motors may be coupled. We recently identified an interaction between the cytoplasmic dynein-1 activating adaptor Hook3 and the kinesin-3 KIF1C. Here, using in vitro reconstitutions with purified components, we show that KIF1C and dynein/dynactin can exist in a complex scaffolded by Hook3. Full-length Hook3 binds to and activates dynein/dynactin motility. Hook3 also binds to a short region in the "tail" of KIF1C, but unlike dynein/dynactin, this interaction does not activate KIF1C. Hook3 scaffolding allows dynein to transport KIF1C toward the microtubule minus end, and KIF1C to transport dynein toward the microtubule plus end. In cells, KIF1C can recruit Hook3 to the cell periphery, although the cellular role of the complex containing both motors remains unknown. We propose that Hook3's ability to scaffold dynein/dynactin and KIF1C may regulate bidirectional motility, promote motor recycling, or sequester the pool of available dynein/dynactin activating adaptors

An analysis of high ionosphere positive ion ram probes

Analysis of rocketborne ion probe data from upper ionosphere, for planar and spherical probe geometrie

De Principe

[Italiano]: Nella presente edizione il lavoro di filologia si intreccia con quello di edizione digitale, creando un testo consultabile a più livelli. Nel testo digitale (digitalhumanities.unior.it) si trova l’apparato critico dell’edizione che dà conto delle varianti, la cui stratificazione è chiarita nella Nota al Testo. In entrambe le edizioni è possibile leggere la traduzione in italiano della precedente porzione testuale; nel testo digitale alcune note filologiche sono accompagnate da una nota critica che commenta le varianti. Con questa pubblicazione digitale, si dà inizio alla collana Unior Digital Humanities, diretta da Carlo Vecce, con la speranza che l’esperienza della filologia insieme alle nuove acquisizioni metodologiche offerte dal digitale possa offrire nuovi spunti alla ricerca umanistica./[English]: In this edition the philology’s work is intertwined with the digital edition, creating a text that can be consulted on several levels. In the digital text (available at digitalhumanities.unior.it) the reader can find the critical apparatus of the edition, whic describes the variants and the stratification of the text. Is possibile to read the italian translation and, in the digital text, some philological notes are accompanied by a critical note wich comments the variants. With this book, begins the Unior Digital Humanities Series, directed by Carlo Vecce

Speeding through cell cycle roadblocks: Nuclear cyclin D1-dependent kinase and neoplastic transformation

Mitogenic induction of cyclin D1, the allosteric regulator of CDK4/6, is a key regulatory event contributing to G1 phase progression. Following the G1/S transition, cyclin D1 activation is antagonized by GSK3β-dependent threonine-286 (Thr-286) phosphorylation, triggering nuclear export and subsequent cytoplasmic degradation mediated by the SCFFbx4-αBcrystallin E3 ubiquitin ligase. Although cyclin D1 overexpression occurs in numerous malignancies, overexpression of cyclin D1 alone is insufficient to drive transformation. In contrast, cyclin D1 mutants refractory to phosphorylation-dependent nuclear export and degradation are acutely transforming. This raises the question of whether overexpression of cyclin D1 is a significant contributor to tumorigenesis or an effect of neoplastic transformation. Significantly, recent work strongly supports a model wherein nuclear accumulation of cyclin D1-dependent kinase during S-phase is a critical event with regard to transformation. The identification of mutations within SCFFbx4-αBcrystallin ligase in primary tumors provides mechanistic insight into cyclin D1 accumulation in human cancer. Furthermore, analysis of mouse models expressing cyclin D1 mutants refractory to degradation indicate that nuclear cyclin D1/CDK4 kinase triggers DNA re-replication and genomic instability. Collectively, these new findings provide a mechanism whereby aberrations in post-translational regulation of cyclin D1 establish a cellular environment conducive to mutations that favor neoplastic growth

Carmen Virgini Matri sacrum

Kotorski pjesnik Ludovik Paskalić (o. 1500-1551) napisao je pet soneta i jednu latinsku eklogu povodom smrti svojega prijatelja Ludovika Pontana, kojemu, prema njegovim riječima, među suvremenicima nije bilo ravna umom, umijećima i krepostima. Juraj Bizanti (o. 1490-1560) posvjedočio je kako je Pontano pisao prozu i stihove, a pjesma Carmen Virgini Matri sacrum, duga 107 elegijskih distiha, koju je upravo Bizanti objavio u svojoj zbirci Rime amorose 1532, jedino je Pontanovo djelo koje nam je ostalo sačuvano. U pokušajima da se identificira ovoga književnika događale su se od početka devetnaestoga stoljeća naovamo višestruke zabune i pogrešna tumačenja, koja su dovela do toga da se i danas o njemu govori s nesigurnošću. Pozornost na Pontana svratila nam je novootkrivena zbirka talijanskih pjesama Hanibala Lucića, odnosno Lucićev sonet Paskaliću iz kojega se može iščitati da se Pontano rodio u Kotoru, što pobija pretpostavku da je riječ o humanistu rođenu u Italiji. Ovaj rad donosi prikaz dosadašnjih istraživanja, a potom utvrđuje pouzdane činjenice o Pontanovu identitetu, za koji se može dokazati da zapravo nije sporan, i dodaje također nove pojedinosti za njegov životopis. Napokon, ukazuje na neka dosad neuočena mjesta u Pontanovoj latinskoj pjesmi posvećenoj Djevici Mariji.The Kotor poet Ludovik Paskalić (Lodovico Pascale, Ludovicus Pascalis) (about 1500-1551) wrote five sonnets and a Latin eclogue marking the death of his friend Ludovik Pontano, who, in Paskalić’s words, had no equals among contemporaries for his intelligence, skills and virtues. Juraj Bizanti (Georgio Bizanti, about 1490-1560) tells us that Pontano wrote prose and verse; but the poem Carmen Virgini Matri sacrum, 107 elegiac couplets long, which Bizanti published in his collection Rime amorose, 1532, is the only Pontano work that has come down to us. There have been, in the efforts to identify this writer since the beginning of the 19th century, numerous confusions and erroneous interpretations, to such an extent that even today discussion of him is only tentative. A newly discovered collection of Italian poems written by Hanibal Lucić has directed our attention to Pontano once again; a sonnet addressed to Paskalić reveals that Pontano was born in Kotor, which refutes the claim that he was a humanist born in Italy. After critically reviewing the relevant research, this paper isolates the reliable historical facts relating to Pontano and proceeds to show that his identity is beyond dispute. It also supplies new biographical information, which is combined with a new reading of Pontano’s Latin poem devoted to the Virgin Mary as firmly rooted in the religious traditons of Kotor