Development and application of a sensitive, high precision weighing lysimeter for use in greenhouses

A high precision weighing lysimeter for measuring evapotranspiration in greenhouses was developed. The instrument has a measurement of sensitivity of one part in 106, that is one order of magnitude better than any other so far described in the literature. With it, evaporation rates in a greenhouse, even at night, can be measured on a one minute time scale. Development and construction of the instrument are described and measurements of the transpiration of a tomato crop in a greenhouse are used to demonstrate its capabilities

Solving the stationary Liouville equation via a boundary element method

Intensity distributions of linear wave fields are, in the high frequency limit, often approximated in terms of flow or transport equations in phase space. Common techniques for solving the flow equations for both time dependent and stationary problems are ray tracing or level set methods. In the context of predicting the vibro-acoustic response of complex engineering structures, reduced ray tracing methods such as Statistical Energy Analysis or variants thereof have found widespread applications. Starting directly from the stationary Liouville equation, we develop a boundary element method for solving the transport equations for complex multi-component structures. The method, which is an improved version of the Dynamical Energy Analysis technique introduced recently by the authors, interpolates between standard statistical energy analysis and full ray tracing, containing both of these methods as limiting cases. We demonstrate that the method can be used to efficiently deal with complex large scale problems giving good approximations of the energy distribution when compared to exact solutions of the underlying wave equation

Correcting the polarization effect in low frequency Dielectric Spectroscopy

We demonstrate a simple and robust methodology for measuring and analyzing the polarization impedance appearing at interface between electrodes and ionic solutions, in the frequency range from 1 to $10^6$ Hz. The method assumes no particular behavior of the electrode polarization impedance and it only makes use of the fact that the polarization effect dies out with frequency. The method allows a direct and un-biased measurement of the polarization impedance, whose behavior with the applied voltages and ionic concentration is methodically investigated. Furthermore, based on the previous findings, we propose a protocol for correcting the polarization effect in low frequency Dielectric Spectroscopy measurements of colloids. This could potentially lead to the quantitative resolution of the $\alpha$-dispersion regime of live cells in suspension

Traumatic infratentorial epidural haematoma: presentation and treatment outcome at the Jos University Teaching Hospital, North Central Nigeria

Background: Traumatic infratentorial epidural haematoma (TIEH), also called posterior fossa epidural haematomas when compared to their supratentorial counterparts, are very rare and their presentation nonspecific, accounting for 0.1-0.3% of all head trauma. Data on TIEH in our environment is very scanty. Our objective was to document the different presentations of TIEH and the outcome of management of these patients in our setting.Methods: This was a retrospective study of consecutive patients with head injury in whom non contrast cranial CT scan showed the presence of an infratentorial epidural haematoma and who presented to the Jos university teaching hospital between January 2012 to December 2020. The patients’ demographics, aetiology, clinical features, CT scan findings and outcome of treatment were extracted from the case folders and analysed using simple proportions.Results: There was a total of seven patients with TIEH out of a total of 308 patients with traumatic epidural haematoma, thus accounting for 2.3% of epidural haematomas in our series. All the TIEH were caused by road traffic collisions, all but one (85.7%) occurred in adults. Six (85.7%) of the patients had occipital skull fractures detected with cranial CT scan or at surgery. Two (28.6%) of the patients were managed non-operatively under close monitoring and did well. Five (71.4%) of the patients were managed surgically. There was one death, giving an overall mortality of (14.3%).Conclusions: TIEH is rare, the presentation is non-specific and early surgical decompression is lifesaving in selected patients

Intracranial suppurations surgically managed at Jos, North Central Nigeria: a nine-years retrospective review

Background: Intracranial suppurations are rare but can be fatal entities consisting of pus collection within the intracranial cavity.  The aim of the study was to document the clinical and radiological findings in our patients and the outcome of treatment.Methods: A retrospective analysis of all consecutive patients presenting to the Jos University Teaching Hospital from January 2012 to December 2019. Data of interest were retrieved from their folders and entered into SPSS version 22 and descriptive statistics run on the variables.Results: There were 33 patients within this period, but only 21 had complete records and thus used for the analysis. The median age was 18 years (IQR=29), males accounted for 81% of the patients. The median time to presentation was 14 days (IQR=23). The most common cause of abscess in our series was trauma (surgical and non-surgical) in 38.1%, followed by contiguous spread from the ear or paranasal sinuses (23.8%). The most common symptom was fever occurring in 61.9%, followed by headache 42.8%. In two thirds of the patients, the abscess was intra-axial (the frontal lobe being the most common site). Patients were managed surgically with either a craniotomy (28.6%) or a burr whole (71.4%). A positive culture was obtained in 33.3% of cases.Conclusions: Intracranial suppurations are uncommon, but can occur in the setting of predisposing factors. A high index of suspicion is required to clinch the diagnosis

FLASC: A Flare-Sensitive Clustering Algorithm: Extending HDBSCAN* for Detecting Branches in Clusters

We present FLASC, an algorithm for flare-sensitive clustering. Our algorithm builds upon HDBSCAN* -- which provides high-quality density-based clustering performance -- through a post-processing step that differentiates branches within the detected clusters' manifold, adding a type of pattern that can be discovered. Two variants of the algorithm are presented, which trade computational cost for noise robustness. We show that both variants scale similarly to HDBSCAN* in terms of computational cost and provide stable outputs using synthetic data sets, resulting in an efficient flare-sensitive clustering algorithm. In addition, we demonstrate the algorithm's benefit in data exploration over HDBSCAN* clustering on two real-world data sets.Comment: 20 pages, 11 figures, submitted to ACM TKD

Expansion and Hadronization of a Chirally Symmetric Quark--Meson Plasma

Using a chirally symmetric Lagrangian, which contains quarks as elementary degrees of freedom and mesons as bound states, we investigate the expansion and hadronization of a fireball, which initially contains only quarks and produces mesons by collisions. For this model, we study the time scales of expansion and thermal and chemical equilibration. We find that the expansion progresses relatively fast, leaving not necessarily enough time to establish thermal and chemical equilibrium. Mesons are produced in the bulk of the fireball rather than at a surface, at a temperature below the Mott temperature. Initial density fluctuations become amplified during the expansion. These observations challenge the applicability of hydrodynamical approaches to the expansion of a quark-gluon plasma

Inter-relationships between composition, physicochemical properties and functionality of lecithin ingredients

Background: Lecithin is widely used as an ingredient in the food industry due to its diverse functionality, mainly attributed to phospholipids (PL), the principal constituents. However, a systematic understanding of the functional properties of lecithin ingredients is missing in the literature. Scope and approach: This review outlines recent developments in lecithin from botanical origin and reviews the complex inter-relationships between physicochemical properties of PL in lecithin and selected techno-functional properties in micelles, liposomes and oil-in-water emulsions. Key findings and conclusions: Attributed to their polar phosphatide group and non-polar fatty acids, PL have specific molecular geometries, dissociation constants and charge, which strongly influence their functional properties in micelles, liposomes and oil-in-water emulsions. The PL profile and extrinsic factors (e.g., water, oil, hexane) influence the formation of micelles during separation of lecithin from oil using membrane filtration. In liposomes, PL profile and the presence of surface modifiers (i.e., sterols) affect the particle size and encapsulation efficiency. In emulsion systems, PL and their interaction with minerals and other functional ingredients (e.g., proteins), influence the particle size and physical stability of the oil droplets. This work provides an integrated review of the links between the composition and physicochemical properties of PL, and in turn, scientifically underpins the links between physicochemical and functional properties of lecithin

The Influence of Concentration and Temperature on the Formation of γ-Oryzanol + β-Sitosterol Tubules in Edible Oil Organogels

The gelation process of mixtures of γ-oryzanol and sitosterol structurants in sunflower oil was studied using light scattering, rheology, and micro-scanning calorimetry (Micro-DSC). The relation between temperature and the critical aggregation concentration (CAC) of tubule formation of γ-oryzanol and sitosterol was determined using these techniques. The temperature dependence of the CAC was used to estimate the binding energy and enthalpic and entropic contribution to the tubular formation process. The binding energy calculated at the corresponding temperatures and CACs were relatively low, in order of 2 RT (4.5 kJ mol−1), which is in accord with the reversibility of the tubular formation process. The formation of the tubules was associated with negative (exothermic) enthalpy change (ΔH0) compared with positive entropy term (−T ΔS0 >0), indicating that the aggregation into tubules is an enthalpy-driven process. The oryzanol–sitosterol ratio affected the aggregation process; solutions with ratio of (60 oryzanol–40 sitosterol) started aggregation at higher temperature compared with other ratios