75 research outputs found
An Experimental Platform for Multi-spacecraft Phase-Array Communications
The emergence of small satellites and CubeSats for interplanetary exploration
will mean hundreds if not thousands of spacecraft exploring every corner of the
solar-system. Current methods for communication and tracking of deep space
probes use ground based systems such as the Deep Space Network (DSN). However,
the increased communication demand will require radically new methods to ease
communication congestion. Networks of communication relay satellites located at
strategic locations such as geostationary orbit and Lagrange points are
potential solutions. Instead of one large communication relay satellite, we
could have scores of small satellites that utilize phase arrays to effectively
operate as one large satellite. Excess payload capacity on rockets can be used
to warehouse more small satellites in the communication network. The advantage
of this network is that even if one or a few of the satellites are damaged or
destroyed, the network still operates but with degraded performance. The
satellite network would operate in a distributed architecture and some
satellites maybe dynamically repurposed to split and communicate with multiple
targets at once. The potential for this alternate communication architecture is
significant, but this requires development of satellite formation flying and
networking technologies. Our research has found neural-network control
approaches such as the Artificial Neural Tissue can be effectively used to
control multirobot/multi-spacecraft systems and can produce human competitive
controllers. We have been developing a laboratory experiment platform called
Athena to develop critical spacecraft control algorithms and cognitive
communication methods. We briefly report on the development of the platform and
our plans to gain insight into communication phase arrays for space.Comment: 4 pages, 10 figures, IEEE Cognitive Communications for Aerospace
Applications Worksho
Evaluation of Traditional Indian Antidiabetic Medicinal Plants for Human Pancreatic Amylase Inhibitory Effect In Vitro
Pancreatic α-amylase inhibitors offer an effective strategy to lower the levels of post prandial hyperglycemia via control of starch breakdown. Eleven Ayurvedic Indian medicinal plants with known hypoglycemic properties were subjected to sequential solvent extraction and tested for α-amylase inhibition, in order to assess and evaluate their inhibitory potential on pancreatic α-amylase. Analysis of 91 extracts, showed that 10 exhibited strong Human Pancreatic Amylase (HPA) inhibitory potential. Of these, 6 extracts showed concentration dependent inhibition with IC50 values, namely, cold and hot water extracts from Ficus bengalensis bark (4.4 and 125 μgmL−1), Syzygium cumini seeds (42.1 and 4.1 μgmL−1), isopropanol extracts of Cinnamomum verum leaves (1.0 μgmL−1) and Curcuma longa rhizome (0.16 μgmL−1). The other 4 extracts exhibited concentration independent inhibition, namely, methanol extract of Bixa orellana leaves (49 μgmL−1), isopropanol extract from Murraya koenigii leaves (127 μgmL−1), acetone extracts from C. longa rhizome (7.4 μgmL−1) and Tribulus terrestris seeds (511 μgmL−1). Thus, the probable mechanism of action of the above fractions is due to their inhibitory action on HPA, thereby reducing the rate of starch hydrolysis leading to lowered glucose levels. Phytochemical analysis revealed the presence of alkaloids, proteins, tannins, cardiac glycosides, flavonoids, saponins and steroids as probable inhibitory compounds
BDNF Induced Translation of Limk1 in Developing Neurons Regulates Dendrite Growth by Fine-Tuning Cofilin1 Activity
Dendritic growth and branching are highly regulated processes and are essential for establishing proper neuronal connectivity. There is a critical phase of early dendrite development when these are heavily regulated by external cues such as trophic factors. Brain-derived neurotrophic factor (BDNF) is a major trophic factor known to enhance dendrite growth in cortical neurons, but the molecular underpinnings of this response are not completely understood. We have identified that BDNF induced translational regulation is an important mechanism governing dendrite development in cultured rat cortical neurons. We show that BDNF treatment for 1 h in young neurons leads to translational up-regulation of an important actin regulatory protein LIM domain kinase 1 (Limk1), increasing its level locally in the dendrites. Limk1 is a member of serine/threonine (Ser/Thr) family kinases downstream of the Rho-GTPase pathway. BDNF induced increase in Limk1 levels leads to increased phosphorylation of its target protein cofilin1. We observed that these changes are maintained for long durations of up to 48 h and are mediating increase in number of primary dendrites and total dendrite length. Thus, we show that BDNF induced protein synthesis leads to fine-tuning of the actin cytoskeletal reassembly and thereby mediate dendrite development
Decoupling Information and Connectivity via Information-Centric Transport
The power of Information-Centric Networking (ICN) architectures lies in their abstraction for communication --- the request for named data. This abstraction promises that applications can choose to operate only in the information plane, agnostic to the mechanisms implemented in the connectivity plane. However, despite this powerful promise, the information and connectivity planes are presently coupled in today\u27s incarnations of leading ICNs by a core architectural component, the forwarding strategy. Presently, this component is not sustainable: it implements both the information and connectivity mechanisms without specifying who should choose a forwarding strategy --- an application developer or the network operator. In practice, application developers can specify a strategy only if they understand connectivity details, while network operators can assign strategies only if they understand application expectations.
In this paper, we define the role of forwarding strategies, and we introduce Information-Centric Transport (ICT) as an abstraction for cleanly decoupling the information plane from the connectivity plane. We discuss how ICTs allow applications to operate in the information plane, concerned only with namespaces and trust identities, leaving network node operators free to deploy whatever strategy mechanisms make sense for the connectivity that they manage. To illustrate the ICT concept, we demonstrate ICT-Sync and ICT-Notify. We show how these ICTs 1) enable applications to operate regardless of connectivity details, 2) are designed to satisfy a predefined set of application requirements and are free from application-specifics, and 3) can be deployed by network operators where needed, without requiring any change to the application logic
2,4,6-Tris(1-oxo-2-pyridylsulfanylmethyl)mesitylene methanol solvate
In the title compound, C27H27N3O3S3·CH4O, the dihedral angles formed by the mesitylene ring with the three oxopyridyl rings are 89.6 (1), 75.5 (1) and 80.69 (1)°, indicating that all three are nearly perpendicular to the mesitylene ring. Intramolecular C—H⋯S hydrogen bonds generate S(6) ring motifs. The crystal structure is stabilized by intramolecular C—H⋯S and intermolecular C—H⋯O hydrogen bonds and weak C—H⋯π interactions
Electronic structure, phase stability and chemical bonding in ThAl and ThAlH
We present the results of theoretical investigation on the electronic
structure, bonding nature and ground state properties of ThAl and
ThAlH using generalized-gradient-corrected first-principles
full-potential density-functional calculations. ThAlH has been reported
to violate the "2 \AA rule" of H-H separation in hydrides. From our total
energy as well as force-minimization calculations, we found a shortest H-H
separation of 1.95 {\AA} in accordance with recent high resolution powder
neutron diffraction experiments. When the ThAl matrix is hydrogenated, the
volume expansion is highly anisotropic, which is quite opposite to other
hydrides having the same crystal structure. The bonding nature of these
materials are analyzed from the density of states, crystal-orbital Hamiltonian
population and valence-charge-density analyses. Our calculation predicts
different nature of bonding for the H atoms along and . The strongest
bonding in ThAlH is between Th and H along which form dumb-bell
shaped H-Th-H subunits. Due to this strong covalent interaction there is very
small amount of electrons present between H atoms along which makes
repulsive interaction between the H atoms smaller and this is the precise
reason why the 2 {\AA} rule is violated. The large difference in the
interatomic distances between the interstitial region where one can accommodate
H in the and planes along with the strong covalent interaction
between Th and H are the main reasons for highly anisotropic volume expansion
on hydrogenation of ThAl.Comment: 14 pages, 9 figure
Crop physiology of elephant foot yam (Amorphophallus paeoniifolius (Dennst. Nicolson)
Amorphophallus paeoniifolius (Dennst. Nicolson), syn. A. campanulatus (Roxb.) BL. exDence (also elephant foot yam) is largely cultivated in the Philippines, Java, Indonesia, Sumatra, Malaysia, Bangladesh, India and China. In India, it is cultivated in the states of Andhra Pradesh, West Bengal, Gujarat, Kerala, Tamil Nadu, Maharashtra, Uttar Pradesh and Jarkhand. Sree Padma, Gajendra, Sree Athira (a hybrid), Bidhan Kusum and NDA-9 are some of the high yielding Amorphophallus varieties released for cultivation. The corm production potential of this crop is 50-80 t ha-1 and net economic return is about 2000 – 3000 US$ per ha. Plant growth and corm yield is influenced by the size of planting material (corms/cormels/corm pieces), plant spacing, nutrient management and water availability. Nevertheless, the production aspect of this crop is less understood as scanty research has been conducted in this crop. The available literature on growth and productivity of elephant foot yam is briefly described in this article
17th IEEE Real-Time Systems Symposium: Work in Progress Sessions
The Table of Contents for the workshop is contained in 1996-027-00main.pdfDear Colleagues:
This year marks the beginning of a new tradition within the Real-Time Systems Symposium, that of holding special sessions for the presentation of new and on-going projects in real-time systems. The prime purpose of these Work In Progress (WIP) sessions is to provide researchers in Academia and Industry an opportunity to discuss their evolving ideas and gather feedback thereon from the real-time community at large. The idea of holding these sessions is timely, and I am pleased to report that this year RTSS'96 WIP received 22 submissions, of which 14 have been accepted for presentation during the symposium and for inclusion in RTSS'96 WIP proceedings.
Many people worked hard to make the idea of holding the WIP sessions a reality. In particular, I would like to thank Sang Son for his hard work in accommodating the WIP sessions within the busy schedule of RTSS'96. Also, I would like to thank all members of the RTSS'96 Program Committee, Al Mok and Doug Locke in particular, for their encouragement and constructive feedback regarding the organization of these sessions. Finally, I would like to thank all those who submitted their work to RTSS'96 WIP and those from RTSS'96 program committee who helped review these submissions.
I hope these sessions will prove beneficial, both to the WIP presenters and to RTSS'96 attendees.
Azer Bestavros
RTSS'96 WIP Chair December 1996.IEEE-CS TC-RT
Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study
PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks
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