Acoustic gravity waves: A computational approach

This paper discusses numerical solutions of a hyperbolic initial boundary value problem that arises from acoustic wave propagation in the atmosphere. Field equations are derived from the atmospheric fluid flow governed by the Euler equations. The resulting original problem is nonlinear. A first order linearized version of the problem is used for computational purposes. The main difficulty in the problem as with any open boundary problem is in obtaining stable boundary conditions. Approximate boundary conditions are derived and shown to be stable. Numerical results are presented to verify the effectiveness of these boundary conditions

Persistence of RNAi-Mediated Knockdown in Drosophila Complicates Mosaic Analysis Yet Enables Highly Sensitive Lineage Tracing.

RNA interference (RNAi) has emerged as a powerful way of reducing gene function in Drosophila melanogaster tissues. By expressing synthetic short hairpin RNAs (shRNAs) using the Gal4/UAS system, knockdown is efficiently achieved in specific tissues or in clones of marked cells. Here we show that knockdown by shRNAs is so potent and persistent that even transient exposure of cells to shRNAs can reduce gene function in their descendants. When using the FLP-out Gal4 method, in some instances we observed unmarked "shadow RNAi" clones adjacent to Gal4-expressing clones, which may have resulted from brief Gal4 expression following recombination but prior to cell division. Similarly, Gal4 driver lines with dynamic expression patterns can generate shadow RNAi cells after their activity has ceased in those cells. Importantly, these effects can lead to erroneous conclusions regarding the cell autonomy of knockdown phenotypes. We have investigated the basis of this phenomenon and suggested experimental designs for eliminating ambiguities in interpretation. We have also exploited the persistence of shRNA-mediated knockdown to design a sensitive lineage-tracing method, i-TRACE, which is capable of detecting even low levels of past reporter expression. Using i-TRACE, we demonstrate transient infidelities in the expression of some cell-identity markers near compartment boundaries in the wing imaginal disc

A Methodology for Engineering Collaborative and ad-hoc Mobile Applications using SyD Middleware

Today’s web applications are more collaborative and utilize standard and ubiquitous Internet protocols. We have earlier developed System on Mobile Devices (SyD) middleware to rapidly develop and deploy collaborative applications over heterogeneous and possibly mobile devices hosting web objects. In this paper, we present the software engineering methodology for developing SyD-enabled web applications and illustrate it through a case study on two representative applications: (i) a calendar of meeting application, which is a collaborative application and (ii) a travel application which is an ad-hoc collaborative application. SyD-enabled web objects allow us to create a collaborative application rapidly with limited coding effort. In this case study, the modular software architecture allowed us to hide the inherent heterogeneity among devices, data stores, and networks by presenting a uniform and persistent object view of mobile objects interacting through XML/SOAP requests and responses. The performance results we obtained show that the application scales well as we increase the group size and adapts well within the constraints of mobile devices

A comprehensive approach to quality management of intensive care services

Purpose – The purpose of this paper is to develop a comprehensive framework for improving intensive care unit performance. Design/methodology/approach – The study introduces a quality management framework by combining cause and effect diagram and logical framework. An intensive care unit was identified for the study on the basis of its performance. The reasons for not achieving the desired performance were identified using a cause and effect diagram with the stakeholder involvement. A logical framework was developed using information from the cause and effect diagram and a detailed project plan was developed. The improvement projects were implemented and evaluated. Findings – Stakeholders identified various intensive care unit issues. Managerial performance, organizational processes and insufficient staff were considered major issues. A logical framework was developed to plan an improvement project to resolve issues raised by clinicians and patients. Improved infrastructure, state-of-the-art equipment, well maintained facilities, IT-based communication, motivated doctors, nurses and support staff, improved patient care and improved drug availability were considered the main project outputs for improving performance. The proposed framework is currently being used as a continuous quality improvement tool, providing a planning, implementing, monitoring and evaluating framework for the quality improvement measures on a sustainable basis. Practical implications – The combined cause and effect diagram and logical framework analysis is a novel and effective approach to improving intensive care performance. Similar approaches could be adopted in any intensive care unit. Originality/value – The paper focuses on a uniform model that can be applied to most intensive care units

Core Loaded Thin-walled Sleeved Column System

In conventional columns, the load carrying capacity is governed by the yield strength of the material and its buckling strength. The yield strength of the compression member is governed by the mechanical property of the material and its area of cross section while its elastic buckling strength depends on the least flexural stiffness (EI) ofthe cross section and its effective unsupported length. The elastic flexural buckling strength of a compression member is given by the well known Euler equation. In practice the strength of conventional compression members is less than bot.h the yield strength and Euler buckling strength due to the effects of imperfections, residual stresses etc.(Bjorhovde(1988)). In this paper behaviour of a novel patented concept, referred to as core loaded thin-walled sleeved column system, is discussed

A Feasibility Study of Public Private Partnership in Sustainable Ethiopia’s Coffee Quality Improvement Programme

The rainforests of the south western Ethiopian highlands are recognised asthe birthplace of Coffea arabica. Ethiopia is the only country in the worldwhere Coffea Arabica (L.) can be found in the wild. The forests that oncedominated the highlands are considerably diminished during the lastdecades. This poses a massive threat to the survival of the genetic resources of Coffea Arabica, 99.8% of the genetic diversity of which is in Ethiopia. As a result, the diversity at origin of some 2,000 or more coffee varieties – unique in the world – is in danger of being irretrievably lost. The monastery islands and environ of Lake Tana had coffee from the South west forests planted 400 years ago by King Fassil of Gonder. This has created a natural ex-situ gene bank in an area otherwise covered with forest. Civilian population pressure since 1974 has reduced the forest for firewood and timber incomes and coffee has been neglected especially during the low price periods. In order to address these issues with sustainable livelihoods, the feasibility of a PPP programme is being studied, incorporating the governments with NGOs and private partners. This paper comprehensively analyses the approaches to study the feasibility and status of Public Private Partnerships (PPPs) in Amhara region specially Zegey peninsula and Lake Tana Island coffee quality improvement. To collect the required information interviews were conducted with concerned stakeholders and a simple questionnaire also prepared and distributed to coffee producing farmers in Amharic language.Key words: Quality Coffee Berries, Pre & Post Harvesting method, Amhararegion- Zegey Peninsula, Feasibility of PPP assistanc

Polynomial disaggregation procedures

January 1991.Includes bibliographical references.In air quality monitoring, often aerosol samples are collected using various filter methods in regular sampling cycles. Some aerosol species samples may be collected at 12 hour cycles while others may be collected at 6 hour cycles or 24 hour cycles, etc. If some species are collected at 6 hour intervals and others at 12 hour intervals, then a statistical analysis of these data are often carried out after aggregating the 6 hour data to produce 12 hour data so that all data correspond to the same time cycle. It is of some interest to investigate the alternative possibility of disaggregating the 12 hour data to obtain "6 hour (pseudo) data" and then performing statistical analyses on the 6 hour scale. In this report we investigate this possibility by studying how well a certain class of disaggregation procedures is able to disaggregate aggregated data. The performance of the methods considered are evaluated using real data collected as part of the WHITEX study.Research supported by the National Oceanic Atmospheric Administration under Grant no. NA90RAH00077

Retinoids Regulate a Developmental Checkpoint for Tissue Regeneration in Drosophila

SummaryDamage to Drosophila imaginal discs elicits a robust regenerative response from the surviving tissue [1–4]. However, as in other organisms, developmental progression and differentiation can restrict the regenerative capacity of Drosophila tissues. Experiments in Drosophila and other holometabolous insects have demonstrated that either damage to imaginal tissues [5, 6] or transplantation of a damaged imaginal disc [7, 8] delays the onset of metamorphosis. Therefore, in Drosophila there appears to be a mechanism that senses tissue damage and extends the larval phase to coordinate tissue regeneration with the overall developmental program of the organism. However, how such a pathway functions remains unknown. Here we demonstrate that a developmental checkpoint extends larval growth after imaginal disc damage by inhibiting the transcription of the gene encoding PTTH, a neuropeptide that promotes the release of the steroid hormone ecdysone. Using a genetic screen, we identify a previously unsuspected role for retinoid biosynthesis in regulating PTTH expression and delaying development in response to tissue damage. Retinoid signaling plays an important but poorly defined role in several vertebrate regeneration models [9–11]. Our findings demonstrate that retinoid biosynthesis in Drosophila is important for the maintenance of a condition that is permissive for regenerative growth

Assembling kidney tissues from cells: the long road from organoids to organs

The field of regenerative medicine has witnessed significant advances that can pave the way to creating de novo organs. Organoids of brain, heart, intestine, liver, lung and also kidney have been developed by directed differentiation of pluripotent stem cells. While the success in producing tissue-specific units and organoids has been remarkable, the maintenance of an aggregation of such units in vitro is still a major challenge. While cell cultures are maintained by diffusion of oxygen and nutrients, three- dimensional in vitro organoids are generally limited in lifespan, size, and maturation due to the lack of a vascular system. Several groups have attempted to improve vascularization of organoids. Upon transplantation into a host, ramification of blood supply of host origin was observed within these organoids. Moreover, sustained circulation allows cells of an in vitro established renal organoid to mature and gain functionality in terms of absorption, secretion and filtration. Thus, the coordination of tissue differentiation and vascularization within developing organoids is an impending necessity to ensure survival, maturation, and functionality in vitro and tissue integration in vivo. In this review, we inquire how the foundation of circulation is laid down during the course of organogenesis, with special focus on the kidney. We will discuss whether nature offers a clue to assist the generation of a nephro-vascular unit that can attain functionality even prior to receiving external blood supply from a host. We revisit the steps that have been taken to induce nephrons and provide vascularity in lab grown tissues. We also discuss the possibilities offered by advancements in the field of vascular biology and developmental nephrology in order to achieve the long-term goal of producing transplantable kidneys in vitro

dbSMR: a novel resource of genome-wide SNPs affecting microRNA mediated regulation

Background: MicroRNAs (miRNAs) regulate several biological processes through post-transcriptional gene silencing. The efficiency of binding of miRNAs to target transcripts depends on the sequence as well as intramolecular structure of the transcript. Single Nucleotide Polymorphisms (SNPs) can contribute to alterations in the structure of regions flanking them, thereby influencing the accessibility for miRNA binding. Description: The entire human genome was analyzed for SNPs in and around predicted miRNA target sites. Polymorphisms within 200 nucleotides that could alter the intramolecular structure at the target site, thereby altering regulation were annotated. Collated information was ported in a MySQL database with a user-friendly interface accessible through the URL: http://miracle.igib.res.in/ dbSMR. Conclusion: The database has a user-friendly interface where the information can be queried using either the gene name, microRNA name, polymorphism ID or transcript ID. Combination queries using 'AND' or 'OR' is also possible along with specifying the degree of change of intramolecular bonding with and without the polymorphism. Such a resource would enable researchers address questions like the role of regulatory SNPs in the 3' UTRs and population specific regulatory modulations in the context of microRNA targets