Tyrimo tikslas - nustatyti paros laiko įtaką trumpųjų nuotolių bėgikų reakcijos trukmei. Tyrimo uždaviniai: 1. Ištirti ir palyginti 2009 m. Universiados vyrų 100 m. bėgimo rezultatų ir reakcijos trukmių kaitą nuo parengiamojo iki finalinio bėgimų. 2. Ištirti ir palyginti 2011 m. Universiados vyrų 100 m. bėgimo rezultatų ir reakcijos trukmių kaitą nuo parengiamojo iki finalinio bėgimų. 3. Ištirti ir palyginti 2009 m. ir 2011 m. Universiadų vyrų 100 m. bėgimo rezultatų ir reakcijos trukmių kaitą nuo parengiamojo iki finalinio bėgimų. 4. Ištirti ir palyginti kaip kinta trumpųjų nuotolių bėgikų bei nesportuojančių asmenų reakcijos trukmės, atliekant ranka skirtingu paros laiku (ryte, diena, vakare). 5. Ištirti ir palyginti kaip kinta trumpųjų nuotolių bėgikų bei nesportuojančių asmenų reakcijos trukmės, atliekant koja skirtingu paros laiku (ryte, diena, vakare). Tyrimo organizavimas: Reakcijos trukmė nustatoma naudojant reakciometrą RA-1. Reakcijos trukmės nustatymui tiriamasis atliko po 10 judesių dešine ranka, po to dešine koja. Trumpųjų nuotolių bėgikai buvo testuojami poilsio dieną, ryte (8:00 – 9:00) per pietus (14:00 – 15:00) ir vakare (21:00 – 22:00). Rezultatai: Išanalizavus 2009 m. pasaulio universiados vyrų 100 m bėgimo rezultatus, pastebėjome, kad prasčiausi rezultatai demonstruojami parengiamuosiuose bėgimuose. Taip pat nustatėme, kad statistiškai reikšmingai rezultatai skyrėsi tik iki pusfinalio (p < 0,05), o finale sportininkų vidutinis bėgimo rezultatas nesiskyrė... [toliau žr. visą tekstą] / The aim of the study: to establish the effects of time of day on reaction times in short distance runners. The goals of the study: 1. To examine and compare men’s 100 meters running performance and reaction times from race preparation to final race in Universiade 2009. 2. To examine and compare men’s 100 meters running performance and reaction times from race preparation to final race in Universiade 2011. 3. To examine and compare men’s 100 meters running performance and reaction times from race preparation to final race in Universiade 2009 and 2011. 4. To examine reaction times in short distance runners and compare the results with reaction times in non-athletes, in the hand test during the different times of the day (morning, afternoon, evening). 5. To examine reaction times in short distance runners and compare the results with reaction times in non-athletes, in the foot test during the different times of the day (morning, afternoon, evening). The organization of research: Reaction time measurement device RA-1 was used to measure reaction time. The subjects had to do 10 hand movements, then 10 foot movements. The sprinters were tested on their day-off, in the morning (8:00-9:00), in the afternoon (14:00-15:00) and in the evening (21:00-22:00). Results: After the analysis of men‘s race results in the Universiade, 2009 it was obvious that the worst results were in race preparation stage. We also found out that the differences according to statistics were significant only... [to full text]

Polyhomologation is a powerful method to prepare polyethylene-based materials with controlled molecular weight, topology and composition. This dissertation focuses on the discovery of new synthetic routes to prepare polyethylene-based macromolecular architectures by combining polyhomologation with highly orthogonal and efficient linking reactions such as Diels Alder, copper-catalyzed azide-alkyne cycloaddition (CuAAC), and Glaser. Taking advantage of functionalized polyhomologation initiators, as well as of the efficient coupling chemistry, we were able to synthesize various types of polymethylene (polyethylene)-based materials with complex architectures including linear co/terpolymers, graft terpolymers, and tadpole copolymers. In the first project, a facile synthetic route towards well-defined polymethylene-based co/terpolymers, by combining the anthracene/maleimide Diels–Alder reaction with polyhomologation, is presented. For the synthesis of diblock copolymers the following approach was applied: (a) synthesis of α-anthracene-ω-hydroxy-polymethylene by polyhomologation using tri (9 anthracene-methyl propyl ether) borane as the initiator, (b) synthesis of furan-protected-maleimide-terminated poly(ε-caprolactone) or polyethylene glycol and (c) Diels–Alder reaction between anthracene and maleimide-terminated polymers. In the case of triblock terpolymers, the α-anthracene-ω-hydroxy polymethylene was used as a macroinitiator for the ring-opening polymerization of D, L-lactide to afford an anthracene-terminated PM-b-PLA copolymer, followed by the Diels–Alder reaction with furan-protected maleimide-terminated poly (ε-caprolactone) or polyethylene glycol to give the triblock terpolymers. The synthetic methodology is general and potentially applicable to a range of polymers. The coupling reaction applied in the second project of this dissertation was copper-catalyzed “click” cycloaddition of azides and alkynes (CuAAC). Novel well-defined polyethylene-based graft terpolymers were synthesized via the “grafting onto” strategy by combining nitroxide-mediated radical polymerization (NMP), polyhomologation and copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC). Three steps were involved in this approach: (a) synthesis of alkyne-terminated polyethylene-b-poly(ε-caprolactone) (PE-b-PCL-alkyne) block copolymers (branches) by esterification of PE-b-PCL-OH with 4-pentynoic acid; the PE-b-PCL-OH was obtained by polyhomologation of dimethylsulfoxonium methylide to afford PE-OH, followed by ring opening polymerization of ε-caprolactone using PE-OH as a macroinitiator (b) synthesis of random copolymers of styrene (St) and 4-chloromethylstyrene (4-CMS) with various CMS contents, by nitroxide-mediated radical copolymerization (NMP), and conversion of chloride to azide groups by reaction with sodium azide (NaN3) (backbone) and (c) “click” linking reaction to afford the PE-based graft terpolymers. This method opens up new routes for the creation of polyethylene-based graft terpolymers by a combination of polyhomologation, NMP and CuAAC. The third project deals with the synthesis of polyethylene-based tadpole copolymer (c-PE)-b-PSt. Cyclic polymers represent a class of understudied polymer architecture mainly due to the synthetic challenges. Within this dissertation, a new method was reported for the synthesis of cyclic polymers in exceptionally high purity and yield. The main approaches to synthesize macrocycles are based on the end-to-end ring-closure (coupling) of homo difunctional linear precursors under high dilution. Our process relies on the preparation of well-defined linear α, ω-dihydroxy polyethylene and a bromide group at the middle of the chain through polyhomologation of ylide using functionalized initiator, followed by ATRP of styrene monomer. The two hydroxyl groups were transformed into alkyne groups, via esterification reaction, followed by Glaser reaction between terminal alkynes to afford the tadpole-shaped copolymers with PE ring and PSt tail. In Our PhD research, we also studied the self-assembly properties of the amphiphilic copolymers PM-b-PEG in aqueous solution by DLS, Cryo-TEM, and AFM. Furthermore, the critical micelle concentration (CMC) was estimated from the intensity of the pyrene emissions by the fluorescence technique. All the findings presented in this dissertation are emphasizing the utility of polyhomologation for the synthesis of well-defined polyethylene-based complex macromolecular architectures, almost impossible through other kind of polymerization including the catalytic polymerization of ethylene.

<p>Automated reaction prediction has the potential to elucidate complex reaction networks for many applications in chemical engineering, including materials degradation, drug design, combustion chemistry and biomass conversion. Unlike traditional reaction mechanism elucidation methods that rely on manual setup of quantum chemistry calculations, automated reaction prediction avoids tedious trial-and-error learning processes and greatly reduces the risk of leaving out important reactions. Despite these promising advantages, the potential of automated reaction prediction as a general-purpose tool is still largely unrealized, due to high computational cost and inconsistent reaction coverage. Therefore, this dissertation develops methods to simultaneously reduce the computational cost and increase the reaction coverage. Specifically, the computational cost is reduced by the development of more efficient transition state (TS) localization workflows and fast molecular and reaction property prediction packages, while the reaction coverage is increased by a comprehensive reaction space exploration based on mathematically defined elementary reaction steps. These components are implemented in two open-source packages, one is TAFFI (Topology Automated Force-Field Interactions) component increment theory (TCIT) and the other is Yet Another Reaction Program (YARP).</p> <p><br></p> <p>The first package, TCIT, is the first component increment theory based molecular property prediction package. TCIT is based on the locality assumption, which decomposes molecular thermochemistry properties into the summation of the contributions of each subgraph. In contrast to the traditional "group" increment theory, TCIT treats each subgraph as the central atom plus its nearest and next-nearest neighboring atoms, and consistently parameterizes the contribution of each component according to purely quantum chemistry calculations. Although all parameterizations are based on quantum chemical calculations, when benchmarked against experimental data, TCIT provides more accurate predictions compared to traditional methods using the same experimental dataset for parameterization. With TCIT, the molecular properties (e.g., enthalpy of formation) and reaction properties (e.g., enthalpy of reaction) can be accurately predicted in an on-the-fly manner. The second package, YARP, is developed for automated reaction space exploration and deep reaction network prediction. By optimizing the reaction enumeration, geometry initialization, and transition state convergence algorithms that are common to many prediction methodologies, YARP (re)discovers both established and unreported reaction pathways and products while simultaneously reducing the cost of reaction characterization nearly 100-fold and increasing convergence of transition states, comparing with recent benchmarks. In addition, an updated version of YARP, YARP v2.0, further reduces the cost of reaction characterization from 100-fold to 300-fold, while increasing the reaction coverage beyond the scope of elementary reaction steps. This combination of ultra-low cost and high reaction-coverage creates opportunities to explore the reactivity of larger systems and more complex reaction networks for applications like chemical degradation, where computational cost is a bottleneck.</p> <p><br></p> <p>The power of TCIT and YARP has been demonstrated by a broad range of applications. In the first application, YARP was used to explore the reactivity of unimolecular and bimolecular reactants, comprising a total of 581 reactions involving 51 distinct reactants. The algorithm discovered all established reaction pathways, where such comparisons are possible, while also revealing a much richer reactivity landscape, including lower barrier reaction pathways and a strong dependence of reaction conformation in the apparent barriers of the reported reactions. Secondly, YARP was applied to the search for prebiotic chemical pathways, which is a long-standing puzzle that has generated a menagerie of competing hypotheses with limited experimental prospects for falsification. With YARP, the space of organic molecules that can be formed within four polar or pericyclic reactions from water and hydrogen cyanide (HCN) was comprehensively explored. A surprisingly diverse reactivity landscape was revealed within just a few steps of these simple molecules and reaction pathways to several biologically relevant molecules were discovered involving lower activation energies and fewer reaction steps compared with recently proposed alternatives. In the third application, predicting the reaction network of glucose pyrolysis, YARP generated by far the largest and most complex reaction network in the domain of biomass pyrolysis and discovered many unexpected reaction mechanisms. Further, motivated by the fact that existing reaction transition state (TS) databases are comparatively small and lack chemical diversity, YARP, together with the concept of a graphically defined model reaction, were utilized to address the data gap by comprehensively characterizing a reaction space associated with C, H, O, and N containing molecules with up to 10 heavy (non-hydrogen) atoms. The resulting dataset, namely Reaction Graph Depth 1 (RGD1) dataset, is composed of 176,992 organic reactions possessing at least one validated TS, activation energy, enthalpy of reaction, reactant and product geometries, frequencies, and atom-mapping. The RGD1 dataset represents the largest and most chemically diverse TS dataset published to date and should find immediate use in developing novel machine learning models for predicting reaction properties. In addition to exploring the molecular reaction space, YARP was also extended to explore and characterize reaction networks in heterogeneous catalysis systems. With ethylene oligomerization on silica-supported single site Ga catalysts as a model system, YARP illustrates how a comprehensive reaction network can be generated by using only graph-based rules for exploring the network and elementary constraints based on activation energy and system size for identifying network terminations. The automated reaction exploration (re)discovered the Ga-alkyl-centered Cossee-Arlman mechanism that is hypothesized to drive major product formation while also predicting several new pathways for producing alkanes and coke precursors. The diverse scope of these applications and milestone quality of many of the reaction networks produced by YARP  illustrate that automated reaction prediction is approaching a general-purpose capability.</p>

No description available.

The temperature profile needed to complete the reaction between the sodium-diamine complex and the isocyanate terminated prepolymer has been established. The sodium diamine complex has the advantage of blocking the nearly instantaneous reaction between the diamine and isocyanate from taking place until it is released at elevated temperatures. Because of its low melting temperature (~40 °C) and its low molecular weight (low viscosity), this chain extension reaction is not dependent on the participation of the prepolymer. Instead, the rate of reaction is dependent on the dissolution of the 4,4’-methylenedianiline (MDA) complex into the system. The dissolution of the MDA complex has been demonstrated to be strongly dependent on particle size. Both the plasticizer Bis(2-ethylhexyl) adipate and the quaternary ammonium compound found in soy lecithin play crucial roles for this reaction. The quaternary ammonium compound is crucial in the dissolution of the complexes. Although the plasticizer has been shown to dissolve the complex to a small extent, the principal role of the plasticizer is to disperse the complexes and to prevent their agglomeration. Other additives such as Dimethyl Sulfoxide (DMSO) have demonstrated to be highly efficient in dissolving the complex. However its effectiveness limits the mixing window needed before reaction take place, resulting in a disadvantage.

" Hydrodechlorination is the reaction of a chlorinated organic compound (R-Cl) with hydrogen to form a carbon-hydrogen bond and HCl: R-Cl + H2 = R-H + HCl. This reaction is used in refrigerant manufacturing, industrial by-product reclamation and waste management. These practical applications require in-depth understanding of hydrodechlorination reaction. In this research work, we studied four families of chlorinated compounds; CF3CF3-xClx(x=1-3), CH4-xClx (x=1-4), CF4-xClx (x=1-4) and dichloropropanes (1,1-, 1,2-, 1,3-, 2,2-), on supported palladium catalysts to create a theory capable of predicting the hydrodechlorination rate on chlorinated compounds and to explore the reaction mechanism. A possible set of elementary reaction steps of hydrodechlorination reaction was proposed from our kinetics study of all these compounds. In this set of reaction steps, the irreversible scission of the first C-Cl bond in a chlorinated compound was proposed to be the rate-determining step; gas phase H2 and HCl were suggested to be in equilibrium with surface H and Cl species; adsorbed Cl was assumed to be the most abundant surface intermediate. The overall rate of hydrodechlorination reaction could be derived from these reaction steps as r=k'[R-Cl]/(1+K'[HCl]/[H2]0.5). In this rate equation, k'is the product of the adsorption equilibrium constant of the chlorinated compound on catalyst surface times the rate constant for the scission of the first C-Cl bond scission step, and K'is the square root of the equilibrium constant for the equilibrium between H2, HCl and their corresponding surface species: 2HCl + 2* = H2 + 2Cl*. The hydrodechlorination reaction of CF3CFCl2 was performed in the presence of H37Cl to study the reversibility of C-Cl bond scission, and the removal of the first Cl atom from CF3CFCl2 was found to be an irreversible step. Hydrodechlorination experiments of CF3CFCl2 with D2 and HCl mixture revealed that D2 and HCl were in equilibrium with surface adsorbed hydrogen and chlorine during reaction. The forward rate and reverse rate of this equilibrium were at least 400 times higher than the overall hydrodechlorination rate. This result supported the assumption of equilibrium for 2HCl + 2* = H2 + 2Cl*. Additionally, the activation energy for the rate determining step was extracted from hydrodechlorination reaction kinetics results of CH4-xClx (x=1-4), CF4-xClx (x=1-4) and dichloropropanes (1,1-, 1,2-, 1,3-, 2,2-) compounds. It was found that for each of the series compounds, a linear relationship existed between C-Cl bond scission activation energy and gas phase C-Cl bond strength. This observation corroborates our assumption that the removal of the first Cl atom from a chlorinated compound is the rate-determining step in the hydrodechlorination reaction. Thus, all kinetic and isotope experimental results obtained from this study are consistent with the proposed reaction steps for the chlorinated compounds tested. This set of reaction steps can also be used to predict the hydrodechlorination reaction rate of a chlorinated compound, once its gas phase C-Cl bond energy is calculated and the turnover rate of a reference chlorinated compound with similar structure is known. Some work has been done to study hydrodechlorination reaction steps and reaction intermediates beyond the rate-limiting step. Isotope tracing experiments with D2 indicated that CH3-, CH2- groups adjacent to a C-Cl bond could undergo deuterium exchange. The study of reactions steps using ab initio methods, including calculation of rate constants, is also under way. Calculations for the CH4-xClx (x=1-4) family showed that the heat of adsorption and C-Cl bond dissociation energy on a Pd surface were linearly related to their gas phase C-Cl bond strength."

Microfabricated thermal cyclers for nucleic acid amplification by using polymerase chain reaction (PCR) have been demonstrated by several groups over the last decade, with improved cycling speed and smaller volumes when compared to conventional bench-top cyclers. However, high fabrication costs coupled with difficulties in temperature sensing and control remain impediments to commercialization. In this study we have used a silicon-glass device that takes advantage of the high thermal conductivity of silicon but at the same time utilizes minimum number of fabrication steps to make it suitable for disposable applications. The thermal cycler is based on noncontact induction heating developed in this group. The microchip reaction kinetics is studied for the first time in-situ during PCR, using a real-time fluorescence block that is capable of data acquisition every 0.7 s from the microchip. The fluorescence information from SYBR green I dye is used to optimize microchip amplification reactions and confirm the product by melting curve analysis. We have also developed a novel non-contact temperature sensing technique using SYBR green fluorescence that can be used for miniaturized PCR devices. The thesis is organized into the following chapters. In chapter 1 we introduce the basic biology ideas that are required to understand DNA amplification. DNA based analysis requires amplification of low initial concentrations to above detectable limits using a technique known as polymerase chain reaction (PCR). In this process, the sample is cycled through three thermal steps for 3040 times to produce multiple copies of DNA. In microchip PCR, conventional polypropylene tubes using 2050 µL volume are replaced by miniaturized devices using ~1 µL sample volumes. The device response improves in terms of ramp rate and total analysis time due to the small volume and smart design of the materials. In this chapter we summarize some of the issues important for miniaturized PCR devices and compare them with commercial tube PCR systems. In chapter 2 we describe the induction heating technique that was developed by our group for miniaturized devices. Induction heating is a noncontact heating technique unlike resistive heating which has been commonly used for microchip PCR. Though resistive heating is very efficient in terms of heat transfer efficiency, it is not suitable for disposable devices and requires multi-step microfabrication. Other non-contact heating techniques such as hot air and IR heating require larger size arrangements that are not suitable for miniaturized devices. The heating was verified by using a thermocouple soldered at the back of the secondary plate that was also used for feedback to the comparator circuit for control. The simple on-off circuit was able to control within ±0.1 ◦C with heating and cooling ramp rates of 25 ◦C/s and 2.5 ◦C/s respectively. In this chapter, we also describe the design and fabrication of the silicon-glass microchip fabricated in our lab. We have used silicon-glass hybrid device for PCR in which glass with a 2 mm drilled hole is anodically bonded to an oxidized silicon surface. The hole formed the static reservoir for 3 µL volume of amplification solution. During PCR, the solution needs to be cycled to high temperature of ~95 ◦C. Hence it was necessary to seal the tiny droplet of liquid against evaporation at this temperature. The devices after being filled by sample were covered by 4 µL of mineral oil to serve as an evaporation barrier. It was easy to recover the whole sample after amplification for further testing. Chapter 3 describes the development of a fluorescent block for SYBR green I dye (SG) used for real-time monitoring of the amplification. The block contains a blue LED for excitation, a dichroic beamsplitter, and silicon photodiode along with filters and focusing optics. Signal levels being weak, we incorporated lock-in detection technique. A TTL at 190 Hz was used to pulse the excitation source and detect the emission at the same frequency using a commercial lock-in amplifier. The block was first characterized using a commercial thermal cycler and polypropylene tubes with different dilution of initial template copy number, and the results crosschecked with agarose gel electrophoresis. Performing continuous monitoring every 0.7s within cycles, we discovered interesting features during extension which have not been studied previously. During the constant temperature extension step, the fluorescence shows a rise and then saturates until the temperature is cycled to the next set point. We have confirmed the same behavior in single cycle extension control experiments and established its connection with polymerase extension activity. We were thus able to extract the activity rate for two different kinds of polymerase in-situ during PCR. By monitoring PCR reactions with different fixed extension times, we were able to determine the optimum conditions for tube PCR. Chapter 4 implements the ideas of fluorescence monitoring from tube that was explained in the previous chapter for the silicon-glass microchip. Since the microchip uses parameters such as sample volume, ramp rates, stay time etc. which are different from tube PCR, we performed several initial test experiments to establish key capabilities such as low volume detection, 3 µL amplification, surface passivation of silicon-glass etc. The same fluorescence block was used to obtain DNA melting point information by continuously monitoring ds-DNA with SG while the temperature is ramped slowly (melting curve analysis). Depending on ds-DNA present, the fluorescence gives a melting temperature (TM ), which was used to calibrate the mix temperature with respect to the thermocouple sensor. After successfully calibrating the microchip, we confirmed complete chip PCR in silicon-glass devices using induction heater. The continuous monitoring of chip PCR gave similar curves as obtained previously for tubes except that the signal level was lower in silicon devices. Extension fluorescence information was used to find an optimum temperature for microchip that shows a maximum activity rate. Similarly the reaction time was optimized in-situ during PCR by using continuous fluorescence data in a feedback experiment. The commercial lock-in amplifier was also replaced by a homemade circuit to successfully pickup fluorescence signal from the microchip during melting curve analysis. In chapter 5, we describe a novel technique to sense the temperature from the microchip without touching the sample volume. Usually the temperature is monitored by a sensor spatially separated from the mix and it has always been challenging to measure the exact temperature accurately. Most of the sensors are not biocompatible and too large in size to be placed inside the small volume of liquid. We have developed a protocol that involves SG fluorescence with addition of excess sensor DNA to the amplification solution. The sensor DNA added into the mix is non specific to the primer used for amplification of the template. It therefore does not participate in the amplification and its number remains unchanged throughout the 3040 cycles of PCR. If the amount of sensor DNA is titrated accurately, it will saturate the fluorescence envelope which then shows very reproducible thermal response with cycling. We have used this thermal response of the fluorescence for feedback as a temperature sensor. The fluorescence feedback was shown to produce identical amount of product in comparison to thermocouple feedback. The product can also be verified by melting curve analysis if the sensor DNA is chosen carefully depending on the product. In this chapter we also discuss some preliminary experiments with smart devices that will use dye based temperature sensor and control along with fluorescence based amplification monitoring. Chapter 6 summarizes the thesis and discusses some of the future areas which can be explored in the field of microchip PCR devices.

Aminoalcohols are very important compounds used in various asymmetric transformations as chiral ligands or chiral auxiliaries. In this thesis, four novel heterocyclic amine substituted chiral 1,4-aminoalcohols were synthesized. In the synthetic strategy, amide esters were synthesized from (2S, 3R)-3-methoxycarbonylbicyclo[2.2.1]hept-5-ene-2-carboxylic acid by DCC coupling method. Subsequent reduction of these amide esters lead to target 1,4-aminoalcohols. The activities of these novel chiral 1,4-aminoalcohols were tested in enantioselective diethylzinc addition, Mukaiyama aldol and Diels-Alder reactions. The enantioselectivities were measured by HPLC. All the products were identified by H NMR and C NMR spectroscopy

M.Sc. (Chemistry) / Please refer to full text to view abstract

The prediction of an atomistic system's macroscopic observables from microscopic physical characteristics is often intractable, either by theory or computation, due to the intrinsic complexity of the underlying dynamical rules. This complexity can be simplified by identifying key mechanisms that drive behavior and considering the system in a reduced representation that captures these mechanisms. Through theory, this thesis examines complex relationships in structured assembly and reaction mechanisms that occur when effective interactions are applied to mesoscale structures. In the first part of this thesis, the structure and assembly of soft matter systems are characterized while varying the interpenetrability of the constituent particles. The nature of the underlying softness allows these systems to be packed at ever higher density, albeit with an increasing penalty in energy. Stochastic equations of motion are developed in which mesoscopic structures are mapped to single degrees of freedom through a coarse-graining procedure. The effective interactions between these coarse-grained sites are modeled using stochastic potentials that capture the spatial behavior observed in systems governed by deterministic bounded potentials. The second part of this thesis presents advancements in time-dependent transition state theory, focusing on chemical reactions that are induced by oscillatory external forces. The optimal dividing surface for a model driven reaction is constructed over a transition state trajectory. The stability of the transition state trajectory is found to directly dictate the reaction rate, and it is thus the fundamental and singular object needed to predict barrier-crossing rates in periodically driven chemical reactions. This thesis demonstrates that using minimalist models to examine these complex systems can provide valuable insight into the dynamical mechanisms that drive behavior.