Order Rate Research Articles

An Approximated Collapsed Variational Bayes Approach to Variable Selection in Linear Regression

In this work, we propose a novel approximated collapsed variational Bayes approach to model selection in linear regression. The approximated collapsed variational Bayes algorithm offers improvements over mean field variational Bayes by marginalizing over a subset of parameters and using mean field variational Bayes over the remaining parameters in an analogous fashion to collapsed Gibbs sampling. We have shown that the proposed algorithm, under typical regularity assumptions, (a) includes variables in the true underlying model at an exponential rate in the sample size, or (b) excludes the variables at least at the first order rate in the sample size if the variables are not in the true model. Simulation studies show that the performance of the proposed method is close to that of a particular Markov chain Monte Carlo sampler and a path search based variational Bayes algorithm, but requires an order of magnitude less time. The proposed method is also highly competitive with penalized methods, expectation propagation, stepwise AIC/BIC, BMS, and EMVS under various settings. Supplementary materials for the article are available online.

Table Tennis Track Detection Based on Temporal Feature Multiplexing Network.

Recording the trajectory of table tennis balls in real-time enables the analysis of the opponent's attacking characteristics and weaknesses. The current analysis of the ball paths mainly relied on human viewing, which lacked certain theoretical data support. In order to solve the problem of the lack of objective data analysis in the research of table tennis competition, a target detection algorithm-based table tennis trajectory extraction network was proposed to record the trajectory of the table tennis movement in video. The network improved the feature reuse rate in order to achieve a lightweight network and enhance the detection accuracy. The core of the network was the "feature store & return" module, which could store the output of the current network layer and pass the features to the input of the network layer at the next moment to achieve efficient reuse of the features. In this module, the Transformer model was used to secondarily process the features, build the global association information, and enhance the feature richness of the feature map. According to the designed experiments, the detection accuracy of the network was 96.8% for table tennis and 89.1% for target localization. Moreover, the parameter size of the model was only 7.68 MB, and the detection frame rate could reach 634.19 FPS using the hardware for the tests. In summary, the network designed in this paper has the characteristics of both lightweight and high precision in table tennis detection, and the performance of the proposed model significantly outperforms that of the existing models.

ADI+MDA orthogonal spline collocation for the pressure Poisson reformulation of the Navier–Stokes equation in two space variables

A numerical method for solving a pressure Poisson reformulation of the Navier–Stokes equation in two space variables is presented. The method discretizes in space using orthogonal spline collocation with splines of order r. The velocity terms are obtained through an alternating direction implicit extrapolated Crank –Nicolson scheme applied to a Burgers’ type equation and the pressure term is found by applying a matrix decomposition algorithm to a Poisson equation satisfying non-homogeneous Neumann boundary conditions at each time level. Numerical results suggest that the scheme exhibits convergence rates of order r in space in the H1 norm and semi-norm for the velocity and pressure terms, respectively, and is order 2 in time. Finally, the scheme is applied to the lid-driven cavity problem and is compared to standard benchmark values.

Cobalt Ferrite Incorporated Ocimum sanctum Nanocomposite Matrix as an Interface for Adsorption of Organic Dyes: A Sustainable Alternative

AbstractThe preparation of Cobalt ferrite‐Ocimum sanctum nanocomposite, referred to as CoFe2O4/OS, has been reported along with its application for the treatment of water containing hazardous organic contaminants. A simple co‐precipitation approach was applied for synthesis of magnetic nanocomposite, and a thorough analysis for its characterization was conducted using several spectroscopic and microscopic techniques. The characterization results showed that the magnetic nanocomposite exhibited substantial functional groups of Ocimum sanctum powder and magnetic ferrite part. The adsorption investigation of nanocomposite for removal of two cationic dyes was carried out with varying parameters, such as pH, contact time, temperature, concentration, and composite dosage. The sorption process was proved feasible and exothermic at the tested temperatures (303–323 K). The sorption data followed Freundlich and Temkin isotherms which recommended the physisorption progression. The kinetic study revealed a pseudo‐second order rate of sorption process for both dye molecules. The facile preparation, economical cost, significant magnetic character, and high sorption capacity will surely construct the water treatment system more competent with the use of CoFe2O4/OS.

Inequalities in SARS-CoV-2 case rates by ethnicity, religion, measures of socioeconomic position, English proficiency, and self-reported disability: cohort study of 39 million people in England during the alpha and delta waves

ObjectiveTo examine sociodemographic inequalities in people with SARS-CoV-2 during the second (alpha) and third (delta) waves of the covid-19 pandemic.DesignRetrospective, population based cohort study.SettingResident population of England.Participants39 006 194 people...

Impact of Multidisciplinary Collaborative Intervention on Isolation Implementation in Prevention and Control of Multi-drug Resistance Infection.

Contact precautions, especially the initiation of isolation, are important measures to prevent and control multidrug-resistant organisms (MDROs). However, the implementation in clinical practice remains weak. This study aimed to analyze the impact of multidisciplinary collaborative intervention on isolation implementation in multidrug-resistant infection, and determine the factors that affect the implementation of isolation measures. A multidisciplinary collaborative intervention related to isolation was conducted at a teaching tertiary hospital in central China on November 1, 2018. The information of 1338 patients with MDRO infection and colonization at 10 months before and after the intervention was collected. Then, the issuance of isolation orders was retrospectively analyzed. Univariate analysis and multivariate logistic regression analysis were performed to analyze the factors that affected the isolation implementation. The overall issuance rate of isolation orders was 61.21%, which increased from 33.12% to 75.88% (P<0.001) after the implementation of the multidisciplinary collaborative intervention. The intervention (P<0.001, OR=0.166) was a promoting factor for the issuance of isolation orders, in addition to the length of stay (P=0.004, OR=0.991), department (P=0.004), and microorganism (P=0.038). The isolation implementation remains far lower than policy standards. Multidisciplinary collaborative interventions can effectively improve the compliance to isolation measures implemented by doctors, thereby promoting the standardized management of MDROs, and providing reference for further improving the quality of hospital infection management.

Dark Comets? Unexpectedly Large Nongravitational Accelerations on a Sample of Small Asteroids

We report statistically significant detections of nonradial, nongravitational accelerations based on astrometric data in the photometrically inactive objects 1998 KY26, 2005 VL1, 2016 NJ33, 2010 VL65, 2016 RH120, and 2010 RF12. The magnitudes of the nongravitational accelerations are greater than those typically induced by the Yarkovsky effect, and there is no radiation-based, nonradial effect that can be so large. Therefore, we hypothesize that the accelerations are driven by outgassing and calculate implied H2O production rates for each object. We attempt to reconcile outgassing-induced acceleration with the lack of visible comae or photometric activity via the absence of surface dust and low levels of gas production. Although these objects are small, and some are rapidly rotating, the surface cohesive forces are stronger than the rotational forces, and rapid rotation alone cannot explain the lack of surface debris. It is possible that surface dust was removed previously, perhaps via outgassing activity that increased the rotation rates to their present-day value. We calculate dust production rates of order ∼10−4 g s−1 in each object, assuming that the nuclei are bare, within the upper limits of dust production from a sample stacked image of 1998 KY26 of g s−1. This production corresponds to brightness variations of order ∼0.0025%, which are undetectable in extant photometric data. We assess the future observability of each of these targets and find that the orbit of 1998 KY26—which is also the target of the extended Hayabusa2 mission—exhibits favorable viewing geometry before 2025.

Abiotic transformations of sulfamethoxazole by hydroxylamine, nitrite and nitric oxide during wastewater treatment: Kinetics, mechanisms and pH effects.

Hydroxylamine (NH2OH), nitrite (NO2-) and nitric oxide (NO), intermediates enzymatically formed during biological nitrogen removal processes, can engage in chemical (abiotic) transformations of antibiotics. This study determined the kinetics, mechanisms and pathways of abiotic transformations of the antibiotic sulfamethoxazole (SMX) by NH2OH, NO2- and NO in a series of batch tests under different pH and oxygen conditions. While NH2OH was not able to directly transform SMX, NO2- (with HNO2 as the actual reactant) and NO can chemically transform SMX primarily through hydroxylation, nitration, deamination, nitrosation, cleavage of S-N, N-C and C-S bonds, and coupling reactions. There were substantial overlaps in transformation product formations during abiotic transformations by HNO2- and NO. The second order rate constants of SMX with NO2- and NO were determined in the range of 1.5×10-1 -4.8×103 M-1 s-1 and 1.0×102 -3.1×104 M-1 s-1, respectively, under varying pH (4-9) and anoxic or oxic conditions. Acidic pH significantly enhanced abiotic transformation kinetics, and facilitated nitration, nitrosation, and cleavage of S-N and N-C bonds. The findings advance our understanding of the fate of antibiotics during biological nitrogen removal, and highlight the role of enzymatically formed reactive nitrogen species in the antibiotic degradation.

Design, synthesis, and stability of (1-amino-4-(3-bromopropoxy)anthracene-9,10‑dione)pentacarbonylrhenium(I) triflate: first X-ray crystallographic structure of a Re(CO)5(N-donor)

In a bid to functionalise doxorubicin with rhenium carbonyl, we designed and synthesized two doxorubicin analogues, 1-(3-trimethylammoniumpropoxy)-4-hydroxyanthraquinone triflate (A1) and 1-amino-4-(3-trimethylammoniumpropoxy) anthraquinone triflate (A2), via a simple 3-step procedure, and obtained X-ray crystal structures for them. Reaction of A1 with Re(CO)5(OTf) afforded complex 1 in 40% yield. Based on a combination of ultraviolet/visible, proton nuclear magnetic resonance spectroscopies, density functional theory calculations, and, in particular, infrared spectroscopy and electrospray ionization mass spectrometry, complex 1 was deduced to be [{fac-Re(CO)3(κ2-deproto-A1)}2(μ2OTf)]OTf, in which A1 coordinates to Re in a bidentate fashion and a triflate anion bridges two Re(CO)3 moieties. Reaction of A2 with various rhenium carbonyl synthons was intractable, but 1-amino-4-(3-bromopropoxy)anthraquinone (A2-a), a precursor of A2, reacted with Re(CO)5(OTf) to yield complex 2 in 65% yield. A single crystal X-ray crystallographic study established complex 2 to be [Re(CO)5(A2-a)]OTf, in which the -NH2 of A2-a coordinates to Re in a monodentate fashion. Complex 2 crystallized in the P21/n monoclinic space group and packs by vertically stacking on top of each other and with a horizontal displacement of 49° from the neighbouring pairs of molecules. This is similar to the crystal packing of A1, but not A2. We observed that complexes 1 and 2 are unstable in solution, and dissociated in dimethylsulfoxide with first order rate constants of 0.029 ± 0.001 h−1 and 18 ± 2 h−1 respectively; in water, complex 1 dissociated almost immediately. Molecular orbital analysis indicated that the low bonding interaction between the coordinating atoms and Re for complex 1 and high energy of the bonding molecular orbital for complex 2 are likely to be the basis of weak coordination of the anthraquinones to rhenium carbonyl. Thus, with regard to the intended objective to modulate the pharmacological profile of doxorubicin, direct coordination of rhenium carbonyl is certainly not feasible.

S-scheme AgIO4/CeO2 heterojunction nanocomposite photocatalyst for degradation of rhodamine B dye

Photocatalysis is auspicious technology for transferring inexhaustible solar energy into storable chemical energy. In this novel research, an auspicious S-scheme heterojunction is constructed by hybridizing CeO2 nanoparticles with band gap energy [2.9 eV], surface area [75 m2/g], and negative conduction band potential (ECB = -0.38 eV) with AgIO4 nanorods with 22 m2/g surface area, band gap energy of 1.98 eV and valence band potential of + 3.27 eV. The novel AgIO4/CeO2 heterojunctions containing different compositions of CeO2 and AgIO4 are fabricated through coupled sol–gel and sonochemical route. SEM, XRD, BET, XPS, DRS, PL and HRTEM investigate the morphological, structural, textural and optical features of the solid specimens. Combined PL and DRS analysis have pointed out that AgIO4 prohibit the as-synthesized heterojunctions with strong visible light absorbability and highly separation efficiency of photogenerated electrons and holes. CeAg15 optimal catalyst decompose RhB dye with pseudo-first order rate of 0.024 min−1 which is tenfold higher than that of pristine CeO2. In the light of scrubber experimental results and PL analysis of terephthalic acid, S-scheme is proposed for analyzing the route of charge transportation and generation of charge carriers with strong redox power. The construction of S-scheme mechanism reveal the preservation of the positive holes of AgIO4 oxidative photocatalyst and negative electrons of CeO2 reductive photocatalyst for consuming in destruction of RhB dye into eco-friendly species as manifested from TOC analysis. This novel research work provide a clear insight on fabrication of S-scheme heterojunction with strong oxidative and reductive power for eradicate water pollutants.

Numerical Modeling of Flow Pattern at a Right-angled River Bend Using CCHE2D Model

In this study, the CCHE2D model is used to analyse the flow pattern in a meander reach of the Gomati River. The finite volume method is used by the numerical model to solve the depth-averaged two-dimensional equations with 𝑘−𝜀turbulence closure. The numerical findings were compared with field data for two different flow rates in order to calibrate the CCHE2D model using various Manning's roughness coefficients. The results show that for the minimum and maximum discharges, a smaller Manning's roughness factor (0.015≥𝑛≥0.025)is more favorableto a higher Manning's roughness factor(0.030≤𝑛≤0.040). The results of the numerical model demonstrated that fluctuations in hydraulic parameters including shear stress, velocity, flow depth, and Froude number in the river bend are greatly influenced by the existence of centrifugal force and helical cells. The linear relationship between velocity and shear stress is presented across the whole study reach, as indicated by the R-squareand linear correlation coefficient (r) components. The results of the model show that the flow field within the river bend can be accurately simulated by the computational model.

Modeling of the mass flow rate of natural gas flow stream using genetic/decision tree/kernel-based data-intelligent approaches

The large consumption of natural gas, one of the most important energy sources in the world, necessitates reliable, precise, and accurate calculation of gas flow rate and amount in order to use this resource in an efficient and sustainable way. The present computational study investigates the possibilities of several soft-computing strategies in estimating the mass flow rate of natural gas flow stream (kg/h) (output variable) based on four input variables of orifice plate diameter ratio, differential pressure of orifice plate (kPa), operating pressure of the natural gas (bar), and operating temperature of the natural gas (°C). A genotype/phenotype genetic algorithm (gene expression programming (GEP) technique), two decision tree-based methods (random forest (RF), random tree (RT) models), and two kernel-based approaches (Gaussian process regression (GPR) and support vector machines (SVM) methods) were applied for the first time to predict gas mass flow rate. Coefficient of correlation (CC), mean absolute error (MAE), root mean square error (RMSE), Scattering index (SI), Nash–Sutcliffe efficiency (NSE), and mean absolute relative error (MARE) were computed as the statistical performance evaluators to determine of the best-performing soft-computing approach. The performance assessment indices corroborated the superiority of the Pearson VII universal kernel function-based GPR model (GPR-PUKF) model (CC = 0.9997, MAE = 64.8091 kg/h, RMSE = 248.7584 kg/h, SI = 0.0237, and NSE = 0.9993 for the testing dataset) over other data-intelligent models in predicting the gas mass flow rate. In addition, statistical results revealed that the predictions of the RF method were better than those of the GEP- and RT-based models, but the GEP approach showed the lowest performance among all applied models. Although the CC values of all models were satisfactory (>0.993), the percentile deviation of GPR model (1.7325%) from the actual values showed competitive lower values, indicating its superior performance than other models (GEP = 15.1436%, RF = 6.5403%, RT = 9.5576%, and SVM = 3.2107%). This study highlighted the significance of employing advanced soft-computing approaches in determining the mass flow rate of natural gas, a vital source of energy, as well as its value to the gas sector.

A q-binomial extension of the CRR asset pricing model

We propose an extension of the Cox-Ross-Rubinstein (CRR) model based on q-binomial (or Kemp) random walks, with application to default with logistic failure rates. This model allows us to consider time-dependent switching probabilities varying according to a trend parameter on a non-self-similar binomial tree. In particular, it includes tilt and stretch parameters that control increment sizes. Option pricing formulas are written using q-binomial coefficients, and we study the convergence of this model to a Black-Scholes type formula in continuous time. A convergence rate of order is obtained.

An adaptive splitting method for the Cox-Ingersoll-Ross process

We propose a new splitting method for strong numerical solution of the Cox-Ingersoll-Ross model. For this method, applied over both deterministic and adaptive random meshes, we prove a uniform moment bound and strong error results of order 1/4 in L1 and L2 for the parameter regime κθ>σ2. We then extend the new method to cover all parameter values by introducing a soft zero region (where the deterministic flow determines the approximation) giving a hybrid type method to deal with the reflecting boundary. From numerical simulations we observe a rate of order 1 when κθ>σ2 rather than 1/4. Asymptotically, for large noise, we observe that the rates of convergence decrease similarly to those of other schemes but that the proposed method making use of adaptive timestepping displays smaller error constants.

Overcultured? Blood cultures on discharged ED patients were ordered more frequently after the SEP-1 bundle initiation

IntroductionIn 2015, the Severe Sepsis and Early Septic Shock Management Bundle (SEP-1) tied hospital reimbursement to performance on a series of time sensitive indicators, including ordering blood cultures on patients with severe sepsis or septic shock. This metric could have broadly shaped ordering practices in the Emergency Department (ED), including for patients who did not have severe sepsis or septic shock. In this study, we sought to evaluate whether the frequency of blood culture orders on adult patients discharged from the ED changed after the SEP-1 metric, whether the rates of positivity for pathogens or contaminants changed after the SEP-1 metric, and whether similar changes were seen in orders for other laboratory tests. MethodsThis was a retrospective evaluation of blood culture orders from discharged adult ED patients from a suburban academic hospital between January 1, 2012 and June 30, 2019. We compared the number of blood cultures per discharged adult patient before and after the SEP-1 metric. We categorized each culture that grew an organism as a pathogen or a contaminant, and we compared rates of pathogen and contaminant growth before and after SEP-1. We compared rates of orders of blood cultures and lactates as labs related to SEP-1 with rates of orders of D-dimers, lipases, human chorionic gonadotropins (HCGs), and brain natriuretic peptides (BNPs) as labs unrelated to SEP-1 before and after the implementation of the SEP-1 metric. ResultsThere were 144,343 adult patients discharged from the ED during the study period. A total of 6754 blood cultures were drawn from 3827 of those patient visits. The rate increased from 43.1 cultures per 1000 discharged patients before the SEP-1 metric to 75.9 blood cultures per 1000 discharged patients, an increase of 76.2% (p < 0.001). The cultures had a decreased rate of positivity (from 3.93% before SEP-1 to 3.03% after SEP-1, p = 0.044) and an unchanged rate of blood cultures resulting in a contaminant (2.49% to 1.85%, p = 0.071). Overall, orders of the labs unrelated to SEP-1 increased by an average of 16.8% after the SEP-1 metric and orders of the labs related to SEP-1 increased by an average of 81.0%. ConclusionAfter the SEP-1 bundle, blood cultures were ordered more frequently on discharged ED patients. These cultures had a lower rate of positivity for pathogens and an unchanged rate of growth of contaminants. This increase was not matched by a similar increase in other labs. Taken together, these findings suggest that the SEP-1 metric had the unintended consequence of increasing orders of blood cultures on patients healthy enough to be discharged from the ED.

Influence of environmental conditions on accumulated polyhydroxybutyrate in municipal activated sludge

Poly(3-hydroxybutyrate) (PHB) was accumulated in full-scale municipal waste activated sludge at pilot scale. After accumulation, the fate of the PHB-rich biomass was evaluated over two weeks as a function of initial pH (5.5, 7.0 and 10), and incubation temperature (25, 37 and 55°C), with or without aeration. PHB became consumed under aerobic conditions as expected with first order rate constants in the range of 0.19 to 0.55 d−1. Under anaerobic conditions, up to 63 percent of the PHB became consumed within the first day (initial pH 7, 55°C). Subsequently, with continued anaerobic conditions, the polymer content remained stable in the biomass. Degradation rates were lower for acidic anaerobic incubation conditions at a lower temperature (25°C). Polymer thermal properties were measured in the dried PHB-rich biomass and for the polymer recovered by solvent extraction using dimethyl carbonate. PHB quality changes in dried biomass, indicated by differences in polymer melt enthalpy, correlated to differences in the extent of PHB extractability. Differences in the expressed PHB-in-biomass melt enthalpy that correlated to the polymer extractability suggested that yields of polymer recovery by extraction can be influenced by the state or quality of the polymer generated during downstream processing. Different post-accumulation process biomass management environments were found to influence the polymer quality and can also influence the extraction of non-polymer biomass. An acidic post-accumulation environment resulted in higher melt enthalpies in the biomass and, consequently, higher extraction efficiencies. Overall, acidic environmental conditions were found to be favourable for preserving both quantity and quality after PHB accumulation in activated sludge.

Impact on Emergency Department Interventions After Implementing a Guideline Based on the Pediatric Emergency Care Applied Research Network Prediction Rule for Identifying Low-Risk Febrile Infants 29 to 60 Days Old.

The Pediatric Emergency Care Applied Research Network (PECARN) prediction rule identifies febrile infants at low risk for serious bacterial infection (SBI). However, its impact on avoidable interventions in the emergency department remains unknown. To study the impact on lumbar puncture (LP) performance, empiric antibiotic use, and admissions after implementing a febrile infant clinical practice guideline for infants aged 29 to 60 days based on the PECARN prediction rule in the pediatric emergency department. This single center preintervention to postintervention study included infants 29 to 60 days old who presented with a chief complaint of fever from November 2018 to November 2021 and were assessed for SBI via blood culture and either urinalysis or urine culture. A new clinical practice guideline based on the PECARN prediction rule was implemented on December 2019. Lumbar puncture attempts, antibiotic administration, and admissions were compared preimplementation and postimplementation and in subgroups of low- and high-risk patients. Of 1597 (PRE: 785, POST: 812) infants presenting with fever, 1032 (PRE: 500, POST: 532) met inclusion criteria. Adoption of guideline recommendations (measured as procalcitonin order rate) was 89.7% in eligible infants postimplementation. Overall, there was a significant decrease in LPs (PRE: 30.6%, POST: 22.6%, P < 0.05) and no significant change in antibiotics or admissions. Among low-risk infants, there was a significant reduction in LPs (PRE: 17.2%, POST: 4.4%, P < 0.05) and antibiotics (PRE: 14.5%, POST: 4.1%; P < 0.05). There was no change in missed SBI (PRE: 3, POST: 2, P = 0.65). No cases of missed meningitis preimplementation or postimplementation were observed. After implementation of a guideline based on the PECARN prediction rule, we observed a reduction of LPs and antibiotics in low-risk infants. Overall, a decrease in LPs was observed, whereas antibiotic use and admissions remained unchanged.

Methylene blue removal from aqueous solutions using a biochar/gellan gum hydrogel composite: Effect of agitation mode on sorption kinetics

Hydrogel membranes are prepared by casting a mixture of gellan gum (associated with PVA) and biochar produced from a local Egyptian plant. The mesoporous material is characterized by a specific surface area close to 134 m2 g−1, a residue of 28 % (at 800 °C), and a pHPZC close to 6.43. After grinding, the material is tested for Methylene Blue sorption at pH 10.5: sorption capacity reaches 1.70 mmol MB g−1 (synergistic effect of the precursors). The sorption isotherms are fitted by both Langmuir and Sips eqs. MB sorption increases with temperature: the sorption is endothermic (∆H°: 12.9 kJ mol−1), with positive entropy (∆S°: 125 J mol−1 K−1). Uptake kinetics are controlled by agitation speed (optimum ≈200 rpm) and resistance to intraparticle diffusion. The profiles are strongly affected by the mode of agitation: the equilibrium time (≈180 min) is reduced to 20–30 min under sonication (especially at frequency: 80 kHz). The mode of agitation controls the best fitting equation: pseudo-first order rate agitation for mechanical agitation contrary to pseudo-second order rate under sonication. The sorption of MB is poorly affected by ionic strength (loss <6 % in 45 g L−1 NaCl solution). Desorption (faster than sorption) is completely achieved using 0.7 M HCl solution. At the sixth recycling, the loss in sorption is close to 5 % (≈ decrease in desorption efficiency). The process is successfully applied for the treatment of MB-spiked industrial solution: the color index decreases by >97 % with a sorbent dose close to 1 g L−1; a higher dose is required for maximum reduction of the COD (60 % at 3 g L−1).

Development of Three˗Tier Diagnostic Test Instrument to Measure Misconceptions of Class XI Students on Reaction Rate Materials

This study aims to measure and detect student misconceptions that occur in the concept of reaction rate based on the diagnosis results of Grade XI Negeri 2 Kabanjahe students and to show subconceptions that experienced both high and low misconceptions. The study was conducted in March–April 2022. The type of research used is Research and Development with ADDIE development. Methods used are tests, anchors, interviews and documentation. The diagnostic test developed is a threetitier multiple choice diagnostic test consisting of an answer choice, reason and confidence level. Validation result by validator indicates the developed instrument is valid. The validity of the developed test is 20 valid problems and 10 invalid problems. Reliability test results show a reliability figure of 0.85. The highest percentage of misconceptions in collision theory is 51.5% and the lowest percentage of misconceptions in reaction order and reaction rate equations is 26.72%. The percentage of students who understand the concept of reaction rate is 35%. The percentage of categories did not understand the concept of reaction rate by 27% and the percentage of misconceptions of reaction rate by 38%.

Suitability Assessment of Two Different Culture Systems for the Rearing of Clarias gariepinus Fingerlings

This paper presents an experiment in which two different fish culture system types were evaluated for the short-term commercial culture of fingerlings of Clarias gariepinus maintained at half the recommended stocking rate; 82.5/m3 in 2 m3 water volume in indoor blue fiber-glass tanks (IFT) and outdoor black plastic tanks (OPT). The research objectives were to assess the suitability and commercial viability of the tanks. Initial mean body weight of graded fingerlings of C. gariepinus for IFT and OPT were 11.32±2.25 g and 10.92±2.44 g (mean±standard deviation) respectively. The study lasted for eight weeks with the fish attaining post-juvenile sizes of 174.95±74.30 g and 178.84±52.04 g (mean±standard deviation) in the IFT and OPT respectively which were not significantly different at p &gt; 0.05. Survival at termination was 81.21±0.0% and 81.21±2.5% for IFT and OPT respectively. As fish attained larger sizes of 100 g and above between weeks 6 and 8, skin lesions and frayed fins were observed in comparatively more of the indoor reared fish than the outdoor reared fish. It may be concluded that the systems are not vastly different in terms of resultant survival and growth performance of the African catfish, however, the culture duration may be halved when maintaining the reported stocking rate in order to prevent distress as a fallout of aggression as they increase in size.