Facile oxidation of aldehydes to carboxylic acids with chromium(V) reagents

Recently we reported a convenient method of oxidation of alcohols to carbonyl compounds using chromium(V) reagents. Although a variety of reagents are available for effecting this transformation, there are only a few reagents which have been successfully used for the oxidation of aldehydes to carboxyllc adds. Chromic acid, silver oxide and potassium permanganate are commonly employed for this purpose and reactions are performed in protic media under conditions which are not that mild. The "non-aqueous" chromium(VI) reagent, pyridinium dichromate, recently reported by Corey oxidises alcohols and aldehydes to carboxylic acids in DMF at room temperature. Although Cr(V) species is postulated as an intermediate in all oxidations with Cr(VI), no systematic oxidation studies have been reported with these reagents. This note reports the results of some fruitful investigations on aldehyde → carboxylic acid conversion involving some "non-aqueous" chromium (V) complexes 1̲, 2̲, 3̲ and 5̲ under anhydrous conditions

Topics, trends, and sentiments of Tweets about the COVID-19 pandemic: temporal infoveillance study

With restricted movements and stay-at-home orders due to COVID-19 pandemic, social media platforms like Twitter have become an outlet for users to express their concerns, opinions and feelings about the pandemic. Individuals, health agencies and governments are using Twitter to communicate about COVID-19. This research builds on the emergent stream of studies to examine COVID-19 related English tweets covering a time period from Jan 1, 2020 to May 9, 2020. We perform a temporal assessment and examine variations in the topics and sentiment-scores to uncover key trends. To examine key themes and topics from COVID-19 related English tweets posted by individuals, and to explore the trends and variations in how the COVID-19 related tweets, key topics and associated sentiments changed over a period of time before and after the disease was declared as pandemic. Combining data from two publicly available COVID-19 tweet datasets with our own search, we compiled a dataset of 13.9 million COVID-19 related English tweets made by individuals. We use Guided latent Dirichlet allocation (LDA) to infer themes and topics underlying the tweets, and use VADER sentiment analysis to compute sentiment scores and examine weekly trends for 17 weeks. Topic modelling yielded 26 topics, grouped into 10 broader themes underlying the COVID-19 tweets. 20.51% of tweets were about COVID-19's impact of economy and markets, followed by spread and growth in cases (15.45%), treatment and recovery (13.14%), impact on healthcare sector (11.40%), and governments' response (11.19%). Average compound sentiment scores were found to be negative throughout the time period of our examination for spread and growth of cases, symptoms, racism, source of the outbreak and political impacts of COVID-19. In contrast, we saw a reversal of sentiments from negative to positive for prevention, impact on economy and market, governments' response, impact on healthcare industry, treatment and recovery. Identification of dominant themes, topics, sentiments and changing trends about COVID-19 pandemic can help governments, healthcare agencies and policy makers to frame appropriate responses to prevent and control the spread of pandemic

The QUIC Fix for Optimal Video Streaming

Within a few years of its introduction, QUIC has gained traction: a significant chunk of traffic is now delivered over QUIC. The networking community is actively engaged in debating the fairness, performance, and applicability of QUIC for various use cases, but these debates are centered around a narrow, common theme: how does the new reliable transport built on top of UDP fare in different scenarios? Support for unreliable delivery in QUIC remains largely unexplored. The option for delivering content unreliably, as in a best-effort model, deserves the QUIC designers' and community's attention. We propose extending QUIC to support unreliable streams and present a simple approach for implementation. We discuss a simple use case of video streaming---an application that dominates the overall Internet traffic---that can leverage the unreliable streams and potentially bring immense benefits to network operators and content providers. To this end, we present a prototype implementation that, by using both the reliable and unreliable streams in QUIC, outperforms both TCP and QUIC in our evaluations

A Statistical Graphical Model of the California Reservoir System

The recent California drought has highlighted the potential vulnerability of the state's water management infrastructure to multiyear dry intervals. Due to the high complexity of the network, dynamic storage changes in California reservoirs on a state-wide scale have previously been difficult to model using either traditional statistical or physical approaches. Indeed, although there is a significant line of research on exploring models for single (or a small number of) reservoirs, these approaches are not amenable to a system-wide modeling of the California reservoir network due to the spatial and hydrological heterogeneities of the system. In this work, we develop a state-wide statistical graphical model to characterize the dependencies among a collection of 55 major California reservoirs across the state; this model is defined with respect to a graph in which the nodes index reservoirs and the edges specify the relationships or dependencies between reservoirs. We obtain and validate this model in a data-driven manner based on reservoir volumes over the period 2003–2016. A key feature of our framework is a quantification of the effects of external phenomena that influence the entire reservoir network. We further characterize the degree to which physical factors (e.g., state-wide Palmer Drought Severity Index (PDSI), average temperature, snow pack) and economic factors (e.g., consumer price index, number of agricultural workers) explain these external influences. As a consequence of this analysis, we obtain a system-wide health diagnosis of the reservoir network as a function of PDSI

Characteristics of patients with organic brain syndromes : A cross-sectional 2-year follow-up study in Kuala Lumpur, Malaysia

BACKGROUND: Organic Brain Syndromes (OBS) are often missed in clinical practice. Determining their varied presentations may help in earlier detection, better management, and, assessing prognosis and outcome. We described the in-patient referrals of patients suffering from the psychiatric effects of organic states and compared the symptomatology and mortality between those with the Acute and Chronic varieties. METHODS: 59 patients referred to our Consultation-Liaison (C-L) Psychiatry services and given a clinical diagnosis of OBS were selected over a 6-month period. Psychiatric and cognitive abnormalities and treatment regimes were recorded and fatality rates determined. Information regarding their condition 24 months after their index hospitalization was recorded. All data were entered into a proforma and analyzed after exclusion. RESULTS: The mean duration of detecting the symptoms by the physician was 3.52 days. The presence of a premorbid psychiatric illness had no influence on the clinical presentation but did on the mortality of patients with OBS (p = 0.029). Patients with the Acute syndrome had significantly more symptom resolution as compared to those with the Chronic syndrome (p = 0.001) but mortalityrates did not differ. Elderly patients and those with symptom resolution upon discharge did not show statistically significant higher mortality rates. The most popular combination of treatment was that of a low-dose neuroleptic and a benzodiazepine (34.7%). The need for maintenance treatment was not significantly different in any group, even in those with a past history of a functional disorder. CONCLUSION: Other than the Acute group having a significantly better outcome in terms of symptom resolution, our findings suggest that there was no significant difference in the clinical presentation between those with Acute or Chronic OBS. Mortality-wise, there was also no difference between the Acute and Chronic syndromes, nor was there any difference between the elderly and the younger group. There was also no significant difference in the need for continued treatment in both groups

Best assessment practices of final year engineering projects in Australia

Purpose:The focus of the paper is to explore the best practices for the delivery of final year engineering project. Students use their own initiatives to accomplish practical design projects in their final year of engineering. Each academia proposes different ways of project approaches that should satisfy engineering accreditation requirements for capstone projects. This paper analyses and compares various undergraduate final year engineering project approaches of different universities in Australia. From this case study analysis, this research will explore the best assessment practice for the delivery of final year project. Design/Methodology: Through desktop analysis methodology, this paper will analyse six universities in Australia who are practicing different approaches in their undergraduate final year engineering project. This analysis will look in to the various types of final year projects undertaken, their learning outcomes, teaching methods and assessment measures. Findings: From these 6 case studies, this paper will provide a report on its implementation and assessment impact on final year projects based on the analysed results of qualitative review of course units in undergraduate programs. Conclusions: This paper shows the desktop analysis data and compared the six case studies of Australian universities. The above-summarized different final year engineering project approaches were extremely successful in identifying and promoting creativity and innovation through final year projects. From the comparison, it is clearly shown that Deakin University practices one of best assessment methods for the delivery of final year engineering project