Hydraulic characteristics of pilot distributaries in the Mirpurkhas, Sanghar and Nawabshah districts, Sindh, Pakistan

Discharge frequency / Hydraulics / Flow / Water loss / Seepage / Water distribution / Pakistan / Sindh / Mirpurkhas / Sanghar / Nawabshah

Exploring the differences between forward osmosis and reverse osmosis fouling

A comparison of alginate fouling in forward osmosis (FO) with that in reverse osmosis (RO) was made. A key experimental finding, corroborated by membrane autopsies, was that FO is essentially more prone to fouling than RO, which is opposite to a common claim in the literature where deductions on fouling are often based solely on the water flux profiles. Our theoretical analysis shows that, due to a decrease in the intensity of internal concentration polarization (ICP), and thus an increase in the effective osmotic driving force during FO fouling tests, the similarity of experimental water flux profiles for FO and RO is in accordance with there being greater fouling in FO than RO. The specific foulant resistance for FO was also found to be greater than that for RO. Possible explanations are discussed and these include the influence of reverse solute diffusion from draw solution. Whilst this explanation regarding specific foulant resistance is dependent on the draw solution properties, the finding of greater overall foulant accumulation in FO is considered to be a general finding. Additionally, the present study did not find evidence that hydraulic pressure in RO plays a critical role in foulant layer compaction. Overall this study demonstrated that although FO has higher fouling propensity, it offers superior water flux stability against fouling. For certain practical applications this resilience may be important

The waiting time paradox: population based retrospective study of treatment delay and survival of women with endometrial cancer in Scotland

No abstract available

On-chip spectroscopy with thermally-tuned high-Q photonic crystal cavities

Spectroscopic methods are a sensitive way to determine the chemical composition of potentially hazardous materials. Here, we demonstrate that thermally-tuned high-Q photonic crystal cavities can be used as a compact high-resolution on-chip spectrometer. We have used such a chip-scale spectrometer to measure the absorption spectra of both acetylene and hydrogen cyanide in the 1550 nm spectral band, and show that we can discriminate between the two chemical species even though the two materials have spectral features in the same spectral region. Our results pave the way for the development of chip-size chemical sensors that can detect toxic substances

Asymptotic Behaviour of the Proper Length and Volume of the Schwarzschild Singularity

Though popular presentations give the Schwarzschild singularity as a point it is known that it is spacelike and not timelike. Thus it has a "length" and is not a "point". In fact, its length must necessarily be infinite. It has been proved that the proper length of the Qadir-Wheeler suture model goes to infinity [1], while its proper volume shrinks to zero, and the asymptotic behaviour of the length and volume have been calculated. That model consists of two Friedmann sections connected by a Schwarzschild "suture". The question arises whether a similar analysis could provide the asymptotic behaviour of the Schwarzschild black hole near the singularity. It is proved here that, unlike the behaviour for the suture model, for the Schwarzschild essential singularity $\Delta s$ $\thicksim$ $K^{1/3}\ln K$ and $V\thicksim$ $K^{-1}\ln K$, where $K$ is the mean extrinsic curvature, or the York time.Comment: 13 pages, 1 figur

Guest editorial: Transparency, accountability and the role of control mechanisms during the COVID-19 pandemic: a future research agenda in the context of emerging economies

The rapid spread of the coronavirus (COVID-19) triggered an unprecedented global health crisis. This resulted in governments across the world having to take ‘wartime’ measures in promoting health and safety of their citizens. As a response to the pandemic, governments in different countries, advised by relevant experts, announced countrywide shutdowns, restricting the movement of people, suspending public transportation, and closing most businesses. In many countries, the government also unveiled unprecedented stimulus plans to mitigate the economic impact of the crisis on their citizens. Understandably, due to the nature of the pandemic, much of such public spending had to occur through an expedited process. This, in turn, could potentially create higher risks for corruption and mismanagement (ACCA, 2021). As Transparency International (TI 2020) highlights, extraordinary outbreaks like the COVID19 pandemic also give rise to opportunities for corruption, which might eventually undermine the response to the pandemic. Such corruption can happen in forms, ranging from underreporting of cases to gross irregularities in disbursements of various financial stimulus packages offered by governments

Experience in 118 consecutive patients undergoing CT-guided stereotactic surgery utilizing the cosman-robert-wells (CRW) frame

Aims: To evaluate the efficacy of CT-guided neurosurgical procedures done on patients operated by this modality.Methods: Between January 1997 and March 2000, 118 patients undergoing CT-guided stereotactic procedures were recruited to the study. The CRW III stereotactic system (Radionics, USA) and the TSX-00ZA CT Scanner (Toshiba, Japan) were used for all the procedures in the series. These procedures were directed to symptomatic brain lesions or for the treatment of Parkinsonian tremor.Results: Of 118 patients, 109 had intra-cranial lesions and 9 had Parkinson\u27s Disease. The stereotactic procedures performed on these patients were: biopsies in 62, guided mini-craniotomies in 22, haematoma evacuation in 11 cases, aspiration of abscess in 8 cases, 2 biopsy/aspiration of cysts, 4 placement of catheters and 9 thalamotomies. A histological diagnosis was made in 98.15% while no diagnosis was reached in 1.85%. Morbidity and mortality were 5.92% and 2.55% respectively.Conclusion: CT-guided stereotactic surgery using the CRW frame is accurate, quick, safe and highly effective

Systematic review of prognostic importance of extramural venous invasion in rectal cancer

AIM: To systematically review the survival outcomes relating to extramural venous invasion in rectal cancer. METHODS: A systematic review was conducted using PRISMA guidelines. An electronic search was carried out using MEDLINE, EMBASE, CINAHL, Cochrane library databases, Google scholar and Pubmed until October 2014. Search terms were used in combination to yield articles on extramural venous invasion in rectal cancer. Outcome measures included prevalence and 5-year survival rates. These were graphically displayed using Forest plots. Statistical analysis of the data was carried out. RESULTS: Fourteen studies reported the prevalence of extramural venous invasion (EMVI) positive patients. Prevalence ranged from 9%-61%. The pooled prevalence of EMVI positivity was 26% [Random effects: Event rate 0.26 (0.18, 0.36)]. Most studies showed that EMVI related to worse oncological outcomes. The pooled overall survival was 39.5% [Random effects: Event rate 0.395 (0.29, 0.51)]. CONCLUSION: Historically, there has been huge variation in the prevalence of EMVI through inconsistent reporting. However the presence of EMVI clearly leads to worse survival outcomes. As detection rates become more consistent, EMVI may be considered as part of risk-stratification in rectal cancer. Standardised histopathological definitions and the use of magnetic resonance imaging to identify EMVI will improve detection rates in the future

Phonon runaway in nanotube quantum dots

We explore electronic transport in a nanotube quantum dot strongly coupled with vibrations and weakly with leads and the thermal environment. We show that the recent observation of anomalous conductance signatures in single-walled carbon nanotube (SWCNT) quantum dots can be understood quantitatively in terms of current driven `hot phonons' that are strongly correlated with electrons. Using rate equations in the many-body configuration space for the joint electron-phonon distribution, we argue that the variations are indicative of strong electron-phonon coupling requiring an analysis beyond the traditional uncorrelated phonon-assisted transport (Tien-Gordon) approach.Comment: 8 pages, 6 figure