Compounds Of Formula Research Articles

Radiation attenuation and photoluminescence properties of host tellurite glasses doped with Er3+ ions

The application of shielding is one of the main protective measures in ionizing radiation safety. This paper addresses the influence of erbium oxide (Er2O3) amount fraction on shielding properties of the glass system with compound formula 75TeO2-10Nb2O5-10ZnO-5PbO (TNZP). Addition of Er2O3portions increased samples densities from 5.57 to 5.65 g/cm3. The attenuation properties for the different TNZP-Er2O3samples were simulated using Phy-X/PSD software at vary wide energy ranged from 0.015 to 15 MeV . Various radiation shielding parameters were evaluated including; linear (LAC) and mass (MAC) attenuation coefficients, the half (HVL)- and tenth (TVL)-value layers, the mean (MFP) free path, the total atomic (ACS) and electronic (ECS) cross-sections and fast (FNRCS) neutron-removal cross-section. These parameters were also verified by a comparison with the currently available shielding materials such as RS-253-G18, RS-360, RS-520 and, Chromite, Ferrite, Magnetite, and Barite. Morover the strong green and weak red emission estimated in the prepared glasses under excited 980 nm. Results show that TNZP with high Er2O3constituents is not merely an effective shield for photons but also a good candidate for neutrons protection and theraputic surgery for medical diagnostic applications. The provided esults showed lower FNRCS values compared to the Chromite, Ferrite, and Magnetite. Nevertheless, it can be noticed that the partially added density of Er2O3enhanced FNRCS.

Interview with Dr. Liu Qingquan: Traditional Chinese Medicine for COVID-19 Diagnosis and Treatment

Interview with Dr. Liu Qingquan: Traditional Chinese Medicine for COVID-19 Diagnosis and Treatment

Halogen bonding in uranyl and neptunyl trichloroacetates with alkali metals and improved crystal chemical formulae for coordination compounds.

The structures of the single crystals of compounds K2UO2(tca)4(tcaH)2 (I), K4NpO2(tca)6(tcaH)(H2O)3 (II), Rb4UO2(tca)6(tcaH)(H2O)3 (III), and Cs3UO2(tca)5(tcaH)2·H2O (IV), where tca is the trichloroacetate ion, were established by X-ray diffraction analysis. The crystals of II-IV have a framework structure, whereas in the layered crystals of I, neighboring layers are connected to each other via halogen bonds. In this regard, the crystals of I possess perfect cleavage along the (001) plane: the crystals are easily cut into stacks of very thin layers. Halogen bonds in the structures of all title compounds were characterized using the method of molecular Voronoi-Dirichlet polyhedra. The donor-acceptor halogen bond synthon, where the same halogen atom is both the donor towards one halogen atom and the acceptor from the second halogen atom, is recognized for its usefulness in the crystal design. The description of the ligand coordination modes and crystal chemical formulae of complexes is adapted for cases when ligands have chemically non-equivalent and unobvious donor atoms (for example, oxygen and halogen atoms in halogen-substituted carboxylate anions).

Synthesis, complexation properties, antimicrobial and anticoagulant activity of 2-{3-[4-(dimethylamino)phenyl]-1-hydroxyprop-2-en-1-ylidene}-4-nitro-1H-indene-1,3(2H)-dione

This article presents the synthesis of a new 4-nitro-cinnamoyl derivative of 2-acyl-1,3-indandione. The resulting compound was subjected to interaction with ErCl3x6H2O, which was obtained from Er2O3 and HCl. The synthesized compounds were proven by IR and NMR spectroscopy. The spectral data clearly proves the formation of a chelate complex. A probable structural formula of the coordination compound is also proposed. The obtained compounds were used for analysis of their antimicrobial and anticoagulant activity.

ГОМОЛОГИЧЕСКИЕ СЕРИИ ХИМИЧЕСКИХ СОЕДИНЕНИЙ: ТРЕХ КОМПОНЕНТНЫЕ СИСТЕМЫ (Li+ – Ti4+ – O2–), (Na+ – Ti4+ – O2–), (K+ – V5+ – O2–), (Ba2+ – Cu2+ – O2–) И ЧЕТЫРЕХ КОМПОНЕНТНАЯ СИСТЕМА {Li+ – Fe2+ – (PO4)3–}

The paper presents for the first time a method for calculating the formulas of homological series of chemical compounds of systems (Li+ – Ti4+ – O2–), (Na+ – Ti4+ – O2–), (K+ – V5+ – O2–), {Li+ – Fe2+ – (PO4)3–}, (Ba2+ – Cu2+ – O2). The calculation method is confirmed by a sufficiently large number of experimentally obtained (taken from literature) formulas of chemical compounds: 7 compounds – in the system (Li+ – Ti4+ – O2–), 11 compounds – in the system (Na+ – Ti4+ – O2–), 5 compounds – in the system (K+ – V5+ – O2–), 8 compounds – in the system (Ba2+ – Cu2+ – O2). The formulas of the branches of chemical compounds of the homological series of the corresponding systems have the form: Li4Ti4+nO2(n + 1) (homologues are enriched with TiO2), Na4Ti4+nO2(n + 1) (homologues are enriched with TiO2), K10V5+2nO5(n + 1) (homologues are enriched with V2O5), Li6Fe3n(PO4)2(n + 1) { homologues are enriched with Fe3(PO4)2}, BaCunOn + 1 (homologues are enriched with CuO) и BanCuOn + 1 (homologues are enriched with BaO).

Effectiveness of the Enrichment Activity in Naming and Writing Chemical Formulas Among Grade 10 Students of Bilaran National High School

This study aimed to assess the effectiveness of the enrichment activity in naming and writing chemical formulas among Grade 10 students of Bilaran Natonal High School. Chemical compound names and formulas can be very complex. This competency is a pre-requisite topic to comprehend chemical reactions. Students experience difficulty in dealing with balancing equation without this knowledge. The researcher used the descriptive and the quasi-experimental method of research. A 50-item adapted examination for pre-test and post-test were utilized to determine the effectiveness of enrichment activity. Descriptive evaluation of the Chemistry Name Game Card was employed to identify how the activity impart knowledge to the students through a questionnaire.The outcome reveals that there is an increase and improvement in the mastery of the topic using the enrichment activity. The respondents strongly agree about the effectiveness of the enrichment activity in terms of it’s goal and objective, components and organization, playability and playfulness and usefulness. An action plan was proposed for the continuous improvement in the academic performance of students in naming and writing chemical formulas prior discussing chemical reaction.

Comparison of the Bifidogenic Effects of Goat and Cow Milk-Based Infant Formulas to Human Breast Milk in an in vitro Gut Model for 3-Month-Old Infants.

Human milk contains prebiotic components, such as human milk oligosaccharides (HMOs), which stimulate the growth of specific members of the infant gut microbiota (e.g., Bifidobacteria). Plant-based or synthetic oligosaccharides are often added to infant formulas to simulate the bifidogenic effect of HMOs. Cow milk, the most common source of protein in infant formula, and goat milk, used increasingly in the manufacture of infant formula, contain naturally-occurring prebiotics. This study compared the upper gastrointestinal digestion and subsequent colonic fermentation of human milk vs. goat and cow milk-based infant formulas (goat IF and cow IF, respectively), without additional oligosaccharides using an in vitro model for 3-month-old infants based on the Simulator of the Human Intestinal Microbial Ecosystem (SHIME®). First, a dialysis approach using 3.5 kDa membranes was demonstrated to simulate small intestinal absorption of carbohydrates in conditions similar to those in vivo. During the in vitro digestion experiment, oligosaccharides were detected in human milk and goat IF but barely detected in the cow IF. Further, all three milk matrices decreased colonic pH by boosting acetate, lactate, and propionate production, which related to increased abundances of acetate/lactate-producing Bifidobacteriaceae for human milk (+25.7%) and especially goat IF (33.8%) and cow IF (37.7%). Only cow IF stimulated butyrate production which correlated with an increase in Lachnospiraceae and Clostridiaceae. Finally, Enterobacteriaceae and Acidaminococcaceae also increased with all three milk matrices, while production of proteolytic metabolites (branched-chain fatty acids) was only detected for the cow IF. Overall, goat and cow milk-based formulas without added oligosaccharides impacted gut microbial activity and composition similarly to human milk. This suggests that even without supplementation of formula with oligosaccharides, whole goat milk, whole cow milk and cow milk ingredients already supply compounds in formulas that exert beneficial bifidogenic effects. Further clinical research is warranted to elucidate the effect of whole goat milk-based formulas on the infant gut microbiome.

A propositionalization method of multi-relational data based on Grammar-Guided Genetic Programming

The propositionalization process tries to find distinctive features of the examples in a database to transform such relational data into a simpler representation. More informative features have a positive impact on the classification capabilities of the learning algorithms. In this work, we propose a new propositionalization method, which generates complex Boolean attributes using Grammar-Guided Genetic Programming (G3P). The generated attributes are compound formulas that combine word items coming from a Bag-of-Words (BoW) representation using Boolean operators. The proposal was assessed against three state-of-the-art simple-instance and multiple-instance propositionalization methods. The experimental results show that the proposed method achieves an improvement in terms of classification accuracy and a considerable reduction in the dimensionality of the resulting datasets.

MATCOR, a program for the cross-validation of material properties between databases

Data analytics approaches are increasingly often used to facilitate property-specific materials discovery. The uncertainties in these approaches can be greatly affected by the fidelity of the data sets that are used to train the data models. Therefore, data curation is an essential step for obtaining well-constrained model predictions. This can be a challenging task, especially for data sets that are too large for human quality control. We developed MATCOR, an open source, user-friendly, easily adaptable software to facilitate the data curation process. MATCOR processes lists of material identifiers in either AFLOW or Materials Project format and searches for the best matching materials entry in the other database. This is a non-trivial task due to differences in labeling and/or non-unique usage of material labels. MATCOR uses a combination of characteristics such space group, compound formula, crystal structure and use of Hubbard-U to provide the best possible comparison between databases. The capabilities of MATCOR are demonstrated for density, elastic properties, magnetic properties, and band gap correlations between AFLOW and Materials Project. We find that density shows the highest correlation among the tested properties, 93% of verified densities agree to within ±2%. Bulk- and shear-moduli showed deviations of less than ±10% for 80.6% and 65.1% of the materials, respectively. The classification of materials as non-magnetic/paramagnetic and metallic/gapped are consistent among the two databases for 91% and 69% of the materials, respectively. These examples show that MATCOR can be used to automate and thereby accelerate the data curation process prior to materials discovery through data analytical models.

A simplified strategy for molecular formula determination of chemical constituents in traditional Chinese medicines based on accurate mass, A + 1 and A + 2 isotopic peaks using Fourier transform ion cyclotron resonance mass spectrometry.

Recently, isotopic fine structures derived from Fourier transform ion cyclotron resonance mass spectrometry have been used to determine the molecular formula for unknown compounds in many complex systems. However, a simplified strategy for molecular formula determination of chemical constituents in traditional Chinese medicines (TCMs) based on accurate mass, A + 1 and A + 2 isotopic peaks is necessary. Salviae miltiorrhizae was selected as a representative species. First, the chemical constituents were chromatographically separated and their accurate masses were obtained. The A + 1 and A + 2 isotopic peaks of all chemical constituents were then also acquired. Finally, the chemical formulae of the chemical constituents were determined. In the sample of Salviae miltiorrhizae, the formulae of 38 CHO-containing chemical constituents were quickly determined, and all chemical constituents were identified using their tandem mass spectrometric data. Moreover, the method was validated by comparison of the A + 1 and A + 2 isotopic peaks, their fragmentation patterns and the retention times of six selected standard substances. The results demonstrate that the described strategy performs well for molecular formula determination of chemical constituents in TCMs. This also indicates that this method will be meaningful for the structural identification of chemical constituents of TCMs.

Effects of non-stoichiometry on the microstructure and microwave dielectric properties of Ba1+xCu2V2O8 (x = 0.15, 0.25, 0.35) ceramics

The Ba1+xCu2V2O8 (x = 0.15, 0.25, 0.35) ceramics were synthesized using the conventional solid-state reaction sintering method. The effects of the non-stoichiometry on the crystalline phases, densification sintering, microtopography, and microwave dielectric properties of the Ba1+xCu2V2O8 (x = 0.15, 0.25, 0.35) ceramics were studied. In the sample (x = 1) prepared according to the stoichiometry, only the single crystalline phase of BaCu2V2O8 existed. The excess of Ba2+ ions directly led to the precipitation of a new Ba2V2O7 phase. The detection of element composition using EDS also confirmed the results of the phase composition. The SEM results indicated that the microstructure of the ceramics became loose with the increase of Ba2+ ion content. The theoretical microwave dielectric properties were calculated according to the general formula of compounds. The results of the calculation showed that the precipitation of the Ba2V2O7 phase was the main factor affecting the microwave dielectric properties of the ceramics. The measured results of microwave dielectric properties were consistent with the calculated results. The microwave dielectric properties of the Ba1.35Cu2V2O8 sample calcined at 725 °C for 6 h were shown as follow: er = 12.25, Qf = 46,320 GHz, τf = − 35.3 ppm/°C.

Compound Formulas and Expressions From Sumerian and Akkadian In Modern Languages

سنين طويلة مرت على تأليف الاستاذ الجليل طه باقر كتابه القيم ’من تراثنا اللغوي القديم،(باقر،2010) [i] ذكر فيه العديد من الكلمات، في غالبيتها العظمى اسماء اشياء ونباتات ومعادن واطعمة وادوات وغيرها، تستعمل في اللغات واللهجات العراقية الحديثة وهى من التراث اللغوي لبلاد الرافدين القديم، السومرية والأكدية على وجه التخصيص، وبعضها من الآرامية. ورغم أن ما يحويه الكتاب القيّم المذكور ليس كله موروثا، بل فيه ما هو مشترك بين اللغات السامية، فان محتواه لا يزال من الغنى بحيث يسمح للباحث التوسع والتعمق في اغلب مواده. ومن الملفت ايضا ان الدراسة في حقل هذه اللغات القديمة وما تكشفه من خفاياها، تضيف جديدا كل يوم الى الخزين الكبير من الموروث والى اكتشاف المزيد من المشتركات. وقد اظهرت الدراسات ان السومرية تكاد تكون المصدر الرئيس الذي استعارت منه اللغات الاخرى في بلاد الرافدين وما جاورها وذلك بحكم أنها لغة المؤسسين الرئيسين لحضارة بلاد الرافدين الى جانب مساهمات لا نعرف لحد الآن مداها وحجمها بالضبط من قبل ما يصطلح عليهم باسم ’الفراتيون الاوائل (علي ، 1989 ، ص 30-33 ؛ Rubio , 1999 , p.1-16)،
 
 [i] انظر الطبعة التي صدرت حديثا للكتاب: باقر، طه، من تراثنا اللغوي القديم، لندن (الوراق)، 2010.

A Comparison Between Two Shape Parameters Estimators for (Burr-XII) Distribution

This paper deals with defining Burr-XII, and how to obtain its p.d.f., and CDF, since this distribution is one of failure distribution which is compound distribution from two failure models which are Gamma model and weibull model. Some equipment may have many important parts and the probability distributions representing which may be of different types, so found that Burr by its different compound formulas is the best model to be studied, and estimated its parameter to compute the mean time to failure rate. Here Burr-XII rather than other models is consider because it is used to model a wide variety of phenomena including crop prices, household income, option market price distributions, risk and travel time. It has two shape-parameters (α, r) and one scale parameter (λ) which is considered known. So, this paper defines the p.d.f. and CDF and derives its Moments formula about origin, and also derive the Moments estimators of two shapes parameters (α, r) in addition to maximum likelihood estimators as well as percentile estimators, the scale parameter (λ) is not estimated (as it is considered known). The comparison between three methods is done through simulation procedure taking different sample size (n=30, 60, 90) and different sets of initial values for (α, r, λ).It is observed that the moment estimators are the best estimator with percentage (46%) ,(42%) respectively compared with other estimators.

Dimethyl Ether (DME) and DME/LPG mixtures resistance characteristics of modified natural rubber compounds

The use of Liquified Petroleum Gas (LPG) in Indonesia is quite high, the volume reaches 6.7 million tons per year. Indonesia currently still imports 70% of its domestic consumption of LPG, or about IDR 40 trillion. Imports of Liquid Petroleum Gas (LPG) continues to increase every year. Dimethyl ether (DME) is one alternative to renewable fuels because its availability in the country is quite abundant. When DME applied as household fuels, some components such as metals and rubber should include resistance to DME, such as stoves, rubber hoses, rubber components in regulators and tube valves. Lemigas has succeeded in developing a DME resistant stove but still not found a rubber that is resistant to DME. This research aims to find a natural rubber formula that is resistant to DME and DME / LPG mixture. The study was conducted by varying the dose of sulphur (0.5, 1.5, and 3.5 phr) using 2 types of elastomer, Natural Rubber (NR) and Nitrile Butadiene Rubber (NBR). Immersion was carried out in DME and 3 variations of the DME/LPG mixture (10/90, 20/80, 30/70). The results showed that the compound formula using natural rubber with a sulphur dose of 1.5 phr has the best resistance to DME and DME/LPG mixtures.

Role of Cr doping in tuning the optical and dielectric properties of TiO2 nanostructures

A series of chromium doped titania samples having compound formula Ti1-xCrxO2 (0≤ x ≤ 0.2) were synthesized through cost-effective acid modified sol-gel process. These samples are characterized through several analytical techniques to explore their microstructural phase, optical and dielectric properties. Rietveld refined x-ray diffraction (XRD) patterns confirm the monophase nature with tetragonal crystal structure in anatase phase having I41/amd space group. The average crystallite size as estimated by the Scherrer's equation varies in the range of ~9–14 nm on doping of Cr ions in TiO2. Structural parameters such as lattice constants, bond length (Ti–O), bond angle <Ti–O–Ti> and x-ray density are found to change as a function of Cr doping. The infrared spectroscopy ensures bending/stretching vibrational modes associated with the functional groups at different wavenumbers. Energy bandgap (Eg) as determined using Tauc's relation varies from 3.10 to 3.75 eV with Cr ions substitution in TiO2 matrix that can be ascribed to the creation of oxygen vacancies/defects in the host lattice. However, a fall in the intensity of photoluminescence as observed on doping of Cr ions is associated with the alteration in oxygen vacancies which are directly responsible for the electron-hole recombination rate. The values of Eg indicate inverse dependence with the Urbach energy (Eu) with the increase in dopant ions. The dielectric measurements as a function of frequency exhibit enhancement in the real and imaginary parts of dielectric constant for the same compositions. A deviation from the universal dielectric response (UDR) mechanism is observed at the lower frequencies for all the samples. Additionally, Cole-Cole plots divulge the non-Debye type of relaxation mechanism and ac conductivity follows the Jonscher power law.

An Innovative Method to Understanding Empirical and Molecular Formula of the Chemical Compounds in Numerical Problems

An Innovative Method to Understanding Empirical and Molecular Formula of the Chemical Compounds in Numerical Problems

Study on the mechanism of Gegen Qinlian Decoction for treating type II diabetes mellitus by integrating network pharmacology and pharmacological evaluation

Ethnopharmacological relevanceGegen Qinlian Decoction (GQD) is a classic traditional Chinese medicine prescription that is widely used to clinically treat diabetes mellitus. It is composed of Pueraria lobata (Willd.) Ohwi (ge gen), Scutellaria baicalensis Georgi (huang qin), Coptidis chinensis Franch. (huang lian), and Glycyrrhiza uralensis Fisch. (gan cao). However, the active ingredients in GQD and their mechanism of action are unclear. Aim of the studyIn this study, we aimed to verify the efficacy of GQD in improving insulin resistance (IR) in diabetic mice and used network pharmacology to identify potential targets and pathways underlying its mechanism of action. Materials and methodsA mouse model of diabetes was created by feeding mice a high-fat diet followed by an intraperitoneal injection of streptozotocin. These type II diabetic mice were administered either a clinical dose or a high dose of GQD, after which blood glucose and serum insulin levels were measured to assess its effects on IR. Network pharmacology was used to construct a ‘component-pathway-target’ network to elucidate the likely targets and pathways modulated in common by GQD components. Furthermore, mRNA transcript levels and protein expression levels of oestrogen receptor alpha (ESR1) were determined. ResultsThe in vivo experiment showed that GQD markedly decreased blood glucose and increased serum insulin levels in type II diabetic mice. Network pharmacology and bioinformatics analysis indicated that GQD regulated 82 corresponding proteins and 59 relevant biological pathways associated with diabetes. One such target was ESR1, which was significantly decreased at both the mRNA and protein levels in diabetic mice, but whose levels were significantly increased by GQD treatment. ConclusionsThis project provides a scientific basis for understanding the effectiveness of multi-component, multi-target compound formulas, as well as a new strategy for investigating therapeutic drugs for type II diabetes and other diseases.

Epigastric pain syndrome: What can traditional Chinese medicine do? A randomized controlled trial of Biling Weitong Granules.

BACKGROUNDRecent research suggests that although prokinetic agents, acid suppressors, and radical treatment for Helicobacter pylori infection may be effective in patients with functional dyspepsia (FD), a large proportion of patients still fail to respond to these treatments or may suffer from severe adverse reactions. Many traditional Chinese medicinal herbs can regulate the status of the entire body and have special advantages in the treatment of functional diseases. The present study was designed to verify the efficacy of Biling Weitong Granules (BLWTG), a traditional Chinese medicinal herbal compound formula, in alleviating epigastric pain syndrome (EPS) in FD patients, in an attempt to provide an effective prescription for the clinical treatment of this disease.AIMTo evaluate the clinical efficacy and safety of BLWTG in treating EPS in patients with FD.METHODSIn this multicenter, stratified, randomized, double-blind, placebo-controlled, parallel group clinical trial, eligible patients were randomized into the BLWTG and placebo groups who were treated for 6 wk. Efficacy indicators including the severity and frequency of EPS and the time to pain resolution and safety indicators including adverse events were observed and compared.RESULTSThe baseline demographic data and clinical characteristics, such as epigastric pain symptoms, pain intensity, and frequency of attacks, were matched between the two groups before randomization. After 6 wk of treatment and after the center effect was eliminated, the epigastric pain was significantly improved in 28.33% and 85.59% of the patients in the placebo and BLWTG groups, respectively (P < 0.05). At 6 wk, the resolution rate of epigastric pain was 15% and 69.49% in the placebo and BLWTG groups, respectively (P < 0.05). The differences of total FD clinical score between these two groups were significant (P < 0.05) at 2, 4, and 6 wk (P < 0.05). The scores of each item and the total score in the Functional Digestive Disorders Quality of Life Questionnaire showed significant differences between the two groups at 6 wk after both the center and interaction effects were eliminated (P < 0.05). There was no significant difference in the incidence of adverse events between the two groups, and no serious adverse event was noted during the observation.CONCLUSIONCompared with placebo, BLWTG markedly improved EPS in FD patients without causing serious adverse reactions.

POTENTIAL TRACKING OF CYTOTOXIC ACTIVITIES OF MANGROVE PEREPATE (Sonneratia alba) ROOT EXTRACT AS AN ANTICANCER CANDIDATE

Mangrove plants are one of the most extensive biodiversity in Jambi. Besides functioning as a coastal ecosystem protector, it also has any potential of its chemical content. The study of mangrove’s bioactive compound is important to generate a new therapeutic agent. This study aims to obtain chemical compounds that have cytotoxic activity, reveal the chemical formula and molecular structure of that active compound, and determine the cytotoxic activity level of active compound from perepat (Sonneratia alba) root extract. The extract was isolated and purified using Liquid Vacuum Chromatography, Graphitation Column Chromatography, and Thin Layer Chromatography. The isolate was characterized using FT-IR spectrophotometry. Our result found that it corresponds to the β-sitosterol compound group with a high similarly chromophore. Furthermore, both of the extract and isolate was tested for toxicity activity using the Brine Shrimp Lethality Test (BSLT) method using Artemia salina shrimp larvae. Herein, we reported that acetone isolated extract possesses lower cell death average 100% (start 200 μg/ml) than isolate extract 80% (50μg/ml). Furthermore the toxicity of total extract has LC50 23,98 (μg/ml), while Isolate 10,04 (μg/ml). From the LC50 value, it can be concluded that the toxicity of the extract lower than the isolate, and both were classified as very toxic compounds, and very potential to be developed into anti-cancer drug compounds.

Estimating Population Growth Rates and Instantaneous Population from Periodized Settlement Data

Settlement surveys that yield counts of the number of houses or rooms dated to a chronological period can be used to indicate population and to estimate rates of population growth or decline. Population estimates and population growth rates are, of course, interpretively critical for describing and explaining many aspects of social dynamics. For this sort of survey data, population growth rates can be estimated by applying an ordinary, compound interest formula to room counts, standardized by period length, for successive time periods. This article offers a more nuanced approach that simulates a continuous process of room construction and abandonment, yielding a total number of rooms occupied during a period. The modeled growth rate is the value at which the model total most closely matches the value observed in the settlement data, given the set of model parameters. The model results are sensitive to both structure use-life and the founding room count. This sensitivity does not reflect a defect of the model. Instead it points to a major problem of equifinality—a great variety of different processes could account for the observed data. Exploration of three cases shows that reviewing the model results for a range of combinations of reasonable parameter values can provide demographic insights that are more informative—and can be markedly different—than those provided by the standard formula.