Extra Bonus Research Articles

Exploiting spirooxindoles for dual DNA targeting/CDK2 inhibition and simultaneous mitigation of oxidative stress towards selective NSCLC therapy; synthesis, evaluation, and molecular modelling studies.

The unique structure of spirooxindoles and their ability to feature various pharmacophoric motifs render them privileged scaffolds for tailoring new multitarget anticancer agents. Herein, a stereoselective multicomponent reaction was utilized to generate a small combinatorial library of pyrazole-tethered spirooxindoles targeting DNA and CDK2 with free radical scavenging potential as an extra bonus. The designed spirooxindoles were directed to combat NSCLC via inducing apoptosis and alleviating oxidative stress. The series' absolute configuration was assigned by X-ray diffraction analysis. Cytotoxicity screening of the developed spirooxindoles against NSCLC A549 and H460 cells compared to normal lung fibroblasts Wi-38 revealed the sensitivity of A549 cells to the compounds and raised 6e and 6h as the study hits (IC50 ∼ 0.09 μM and SI > 3). They damaged DNA at 24.6 and 35.3 nM, and surpassed roscovitine as CDK2 inhibitors (IC50 = 75.6 and 80.2 nM). Docking and MDs simulations postulated their receptors binding modes. The most potent derivative, 6e, induced A549 apoptosis by 40.85% arresting cell cycle at G2/M phase, and exhibited antioxidant activity in a dose-dependent manner compared to Trolox as indicated by DPPH scavenging assay. Finally, in silico ADMET analysis predicted the drug-likeness properties of 6e.

Cover Trees Revisited: Exploiting Unused Distance and Direction Information

The cover tree (CT) and its improved version are hierarchical data structures that simplified navigating nets while maintaining good runtime guarantees. They can perform nearest neighbor search in logarithmic time and provide efficient computation in practice. In this paper, we revisit cover trees for nearest neighbor search, and propose a more competitive method. The central idea of our method is to fully exploit the unused distance and direction information. More specially, our method introduces three novel concepts/techniques: (I) range list, (II) quadrant information, and (III) vectorial angle cosine. These techniques are seamlessly integrated into our suggested data structure and search algorithms. As an extra bonus, we explore approximate nearest neighbor and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$k$</tex-math></inline-formula> nearest neighbor based on the proposed techniques, and present algorithms for handling updates. Extensive experimental results, based on both real and synthetic datasets, consistently demonstrate that our method is attractive and competitive, compared against existing cover tree structures for nearest neighbor search and its variants.

The Influence of Intrinsic and Extrinsic Motivation in Workers’ Productivity: Empirical Evidence from the Construction Industry

The human resource remains the most critical productive asset of any organization as it is the human element that gives direction and dynamism to the organization. This study investigated the effect intrinsic motivations and extrinsic motivations have on employee productivity of four selected construction companies in Delta State. To achieve its objectives, the study adopted a quantitative research approach with a survey research design. From a population figure of 242 low-level permanent employees of the four selected construction companies in Delta State, 151 constituted the sample as data were collected through a structured questionnaire using the cross-sectional approach. Descriptive statistics and simple regression analysis were used to analyze the data gathered and test the study hypotheses. Findings revealed that intrinsic motivation has a significant positive effect on employee productivity and extrinsic motivation also exerts a significant positive effect on employee productivity. Also, the most effective tools of extrinsic motivation are competitive salaries, extra work bonuses, and opportunities for promotion. Based on these findings, it was concluded amongst others, that the desire to gain mastery and contributes to societal development through construction-related activities gives low-level construction workers some level of satisfaction and financial-related incentives have an immediate and powerful effect on their performance. The key recommendation of the study is that to make a foster high level of productivity from the employee, top management should adopt a performance-based payment system and sell the benefits of contributing to societal development to the construction workers, acknowledging their contribution through noble initiatives like recognition from an authority, opportunity for mentoring, participation in decision making.

4-(N-Phthalimido)phenyl Isonitrile as a Novel Convertible Isocyanide Analogue with the Odorless Property as an Extra Bonus.

We explored a new isonitrile, namely 4-(N-phthalimido)phenyl isonitrile, with extraordinary features. The novel isocyanide has a pharmacophore, the phthalimido (Pht) group, that possesses promising pharmaceutical activities. We found that the novel isonitrile is unexpectedly odorless as an extra bonus which makes its handling easy in organic synthesis to serve as a scaffold for building several new amide derivatives through multicomponent reactions, overcoming the stink of common aromatic isonitriles such as phenyl isonitrile, benzyl isonitrile, p-nitrophenyl isonitrile, and ethyl 4-isocyano benzoate. The novel isonitrile 9 serves as a source of N-protected isonitrile with a Pht group, where the Pht group can be easily removed via hydrazinolysis, affording the corresponding primary amine/alcohol scaffold which could be used as a precursor to synthesize Passerini products via acylation directly to afford Passerini adducts 14 and 15 without carrying out the traditional Passerini three-component reaction; this new isonitrile is considered as a novel convertible isocyanide analogue.

ANALISIS AGEN TURNOVER,TARGET PENJUALA DAN REALISASINYA PADA PT ASURANSI JIWA CENTRAL ASIA PERWAKILAN MALANG

Indonesia community in general has not constituted community which is insurance minded.In community that has not been insurance minded it almost never exists one who with his own awereness comes to the insurance office to buy life insurance polis,so that insurance companies in Indonesia badly need those persons who are skilled and ready for use to give understanding of the benefit of life insurance and at one to invite then to buy life insurance policy.Thus the company will be faced to a problem if agents who are skilled and ready for use mentioned exit from the company.&#x0D; In conformity with above problem,so this study takes the title ANALISIS OF THE AGENT TURNOVER,SELLING TARGET AND IS REALIZATION IN PT ASURANSI JIWA CENTRAL ASIA RAYA MALANG REPRESENTATIVE.This study aims to know and analize the level of agent turnover in PT Asuransi Jiwa Central Asia Raya Malang Representative and its influence on the realization of mean selling and also to know and analyze there is meaningful difference or not between the mean selling target and mean selling realization.&#x0D; The submitted hypothesis in this study namely:&#x0D; &#x0D; Agent turnover at PT Asuransi Jiwa Central Asia Raya Malang Representative is still high&#x0D; Agent turnover has meaningful negative effwct on the mean selling realization.&#x0D; It occurs meaningful difference between mean selling target and the mean selling realization. For analyzing the problem meantioned to be used labour turnover &#x0D; &#x0D; formula,simple linear regression,correlation analysis,ABC formula and t test.Data which is used is data from the year 1985 up to the year 1989.&#x0D; Based on the study result and test carried out it may be concluded as following:&#x0D; &#x0D; The agent turnover which occurred in PT Asuransi Jiwa Central Asia Raya company Malang Representative is still high,this case per annum as large 51,129 percent,which means larger than its standard agent turnover as large as 40 percent. &#x0D; The magnitude of agent turnover has meaningful negative effect on the Realization of mean policy selling and the realization of mean sum assured selling.Thus if the magnitud of agent turnover declines then the magnitude of mean policy selling realization and the magnitude of mean sum assured selling realization improve.&#x0D; Based on the statistical test,to occur meaningful difference between mean Policy selling target and the mean policy selling realization,likewise for the sum assured it occurs meaningful difference between mean selling target and mean selling realization.&#x0D; &#x0D; Based on the study result and test mentioned above it may be implicated that for improving the mean selling realization it can be carried out by reducing the magnitude of agent turnover,namely by improving the direction,attention and motivation,raising the commision and its incentive to those agent who have not been able to reach selling target and giving extra bonus to those agents who can reach selling target,that is adjusted to the company ability

The Role of Human Capital Investments in Business Excellence of Croatian Companies

The paper analyses human capital investments and their relation to company performance in Croatia. Human capital represents an inevitable element in recognising and measuring an organisation’s values and supporting its business excellence. The results obtained show that training and extra bonuses or salaries are positively correlated with company excellence, as well as show a significant difference in the mean of salaries per employee between high and moderate intensive intellectual capital companies. The differences in company excellence, when human capital expenditures are capitalized in a company’s balance sheet rather than recognized as expenses in the company’s profit and loss account, is confirmed. Companies should pay attention to managing human resources and realizing their importance for business excellence, as well as the importance of appropriate recognition and measurement of human capital in financial statements.

Effect of inactive impurity ions on deuteron beam‐fusion in fast ignition approach

AbstractThe laser‐generated deuteron beam is a promising scheme for providing the required energy for igniting a pre‐compressed fuel in the fast ignition method in the inertial confinement fusion approach. Deuteron beam provides extra energy through beam‐fusion(BF) reactions during the hot‐spot formation in the pre‐compressed fuel. During the compression and hot‐spot formation stages, Impurities are produced due to the mixing of the fuel with the material of the structural elements of the target. So, the efficiency of BF of the deuteron beam in a spherical deuteron‐triton(DT) fuel in the presence of impurity (such as beryllium, carbon, aluminium, and gold) with arbitrary concentration is investigated. Deuteron beam was considered with Maxwellian energy distribution at a temperature of 3 MeV, which passes through the pre‐compressed contaminated DT fuel with a non‐uniform density profile. It shows that an increase of mixed‐ion charge state and density ratio results in the substantial diminution of the deuteron BF probability, which leads to a reduction in deuteron's extra bonus energy. The effect of fuel temperature on the BF probability in contaminated DT fuel is discussed. Calculations show that increasing the temperature enhanced BF probability.

Motivation as an indicator of performance and productivity from the perspective of employees

Abstract Motivation plays a crucial role on employees’ performance. Though organizations have an interest in keeping the employees motivated at work, they do not always have the complete picture on what indeed motivates an employee. Scholars agree that money (including employees’ wages) significantly affects employees’ performance and productivity, but they do not unanimously place it among the strongest determinants of employee motivation. The main purpose of this work was to explore the factors influencing the true motivation of employees to enhance their performance and productivity at work. This study employed a quantitative research design based on data collected during the severe period of the COVID-19 pandemic. There were 110 participants, of which 38 (34.5%) males 72 (65.5%) females working in different companies in Albania. The results showed a moderate level of satisfaction and motivation at work and a significant correlation between the motivation and success of the company. Additionally, the data indicated that most of the participants were satisfied with the financial allowances, but that they aspired to have higher wages and better workplace conditions. Therefore, higher salaries, extra bonuses and the promotion in their role at work or recognition and appreciation seem to be very important motivational factors for the employees. Finally, this study proposes recommendations for companies on how to implement different strategies to increase employees’ motivation and enhance the business effectiveness. This study analyses data collected during the global pandemic and would serve as reference for periods associated with dire financial difficulty.

An exergy analysis and parameter optimization of solid desiccant heat pumps recovering the condensation heat for desiccant regeneration and heat transfer enhancement

Solid desiccant is subjected to remove extra humidity from unsaturated air once thermally regenerated and then sufficiently cooled down. Therefore, it can be incorporated into the traditional vapor compression (VC) systems to handle the latent heat load with elevated evaporation temperature. The condensation heat can be recovered to regenerate the desiccant periodically, with an extra bonus of overall heat transfer enhancement. Such system is named after solid desiccant heat pumps (SDHP), expectedly to deliver higher evaporation temperature and lower pressure ratio at the expenses of the periodical switchover, increased wind friction and slightly impaired sensible heat transfer performance due to the desiccant thermal resistance. To verify the feasibility and superiority of SDHPs, this article proposes a robust thermodynamic model to calculate the operational parameters in SDHPs, such as evaporation temperature, condensation temperature and electricity consumption, corresponding to specific application scenarios. An exergy analysis based on the calculated parameters then followed to identity the origin and destination of the exergy. It concludes that, SDHPs can recover the dehumidification capacity of desiccant by low-grade condensation heat (∼50 °C), with the transfer enhancement up to 120%. Meanwhile, the introduction of the solid desiccant will contribute to a 11%–169% improvement in coefficient of performance (COP) and a 52%–207% improvement in exergy efficiency, in spite of the exergy destruction by air-side friction (<5%) and switchover offset (<10%). Last but not least, for normally encountered latent heat ratio (0.2–0.5), desiccant with linear isotherms or with moderate stepwise position (35–45%) will surpass materials with earlier or later stepwise position.

Vigilantes: An Educational Game Proposal for Health Promotion

Background Technology provides access to knowledge in a pressure-free environment where learning and leisure can work together in order to achieve health promotion through a game. This is the goal of Vigilantes, an application targeted on seven-year-old children and above and elementary teachers as well. Methods The application prototype was built using MIT App Inventor framework and this article is based on information compiled from books, websites, monographs, and periodicals available in the Scielo and PubMed database. In Vigilantes, the user has several missions and challenges with virtual rewards, in addition to extra bonuses meant to encourage the child to learn more about diseases and their preventions. Discussion Games aiming at improving knowledge are a great source of information for children. Parents and teachers should have access to the content available to monitor and encourage the use of the app. Educational games can foster psychomotor, cognitive, behavioral, and social development thus contributing to the learning process. So as to motivate the user correctly, these games must be devised according to the target audience, using appropriate communication. Conclusion The Vigilantes game has been developed with a view to stimulating and disseminating healthy habits in a playful way. It makes room for useful discussion and change of habits that are harmful to health.

The relationship between intrinsic and external motivation towards lesson implementation and application of physical education content among preservice physical education teachers in Thailand

Accomplished physical education (PE) teachers recognize teachers’ motivation, lesson implementation as well as the application of PE contents. This is because these affect teaching effectiveness in PE class. However, a previous study from Koonsri (2016) found that the teachers lacked motivation and focused on extra money or bonus from their teaching. In addition, because the pre-service PE teachers had poor experiences in teaching and controlling the classes, these issues affected the implementation and integration of the PE contents (Claypan, 2014; Kanchana, 2010). Thus, this study examines the relationship between teachers’ motivation, lesson implementation, and application of PE contents among pre-service PE teachers in Southern Thailand. The instruments regarding teachers’ motivation in terms of intrinsic and external motivation, lesson implementation, and application of PE contents were adopted from Tulyakul (2019). The respondents were 157 pre-service PE teachers in five universities in the border provinces of Southern Thailand. The result shows that there is a relationship between intrinsic and external motivation towards lesson implementation and the application of PE contents among the participants. Finally, there are proposed guidelines for the pre-service PE teachers to adjust and develop their teaching performance to enhance students' achievement in the future

Экспаты в российском страховом менеджменте

The article considers the issues of attracting expats to Russia. They were first employed in insurance management in the 1990s. The process was connected with the formation of market relations and the need to attract qualified foreign specialists. Employing expats has several advantages, e.g. advanced business technologies, improving the image of enterprises, personnel training, etc. However, attracting expats has a number of drawbacks, such as the costs associated with remuneration, family support, and extra bonuses. Employing expats has not found wide application in insurance management, since insurance markets vary significantly in institutional and industrial aspects. The automatic transfer of foreign business technologies is limited by legislation, as well as by cultural and historical traditions of Russia. The research objective was to evaluate the activities of expats in Russia, to identify the positive and negative aspects of this phenomenon both for the expats themselves and the country that attracted them, and to justify the limitations of their involvement in insurance management. The research featured the phenomenon of expats in labor markets and their activities in the Russian insurance market. The study revealed the problems associated with the insurance market of the Russian Federation, as well as some options for attracting expats to the Russian insurance management.

Interactive Game Application of Cooking Malay Traditional Cuisines Toward Teenagers in Malaysia

The proposed interactive game application of cooking Malay traditional cuisines is a game designed to teach teenagers aged 12 to 24 years old in the cooking. There were a bunch of interactives cooking game applications on the internet, except for Malay cuisine games. This game is created to attract teenagers to making Malay traditional cuisine in interactive and fun ways. In this game, the user needs to follow the storyline in the game. Then, in the early game, they were given a list of ingredients to make some Malay cuisines. The player will be given the customer’s requested food picture. Then the players need to click the right ingredients in making of the requested food by customer. If the player picks the wrong ingredients, then need to pick the ingredients from the start again. Next, this game concept is casual. With the time given, the players need to complete the order with minimum specific score to move forward to next stage. If they achieve the best result, the player will gain extra money and extra time bonus in the game. This game created with a different type of menus based on every chapter of the story. This game can attract teenagers to learn about cooking and the ingredients used in the food. This game is created to educate teenager yet entertain them at the same time.

Trachyspermum ammi aromatic water: A traditional drink with considerable anti-Candida activity.

Background and Purpose: Aromatic waters (AWs) are therapeutic distillates, which harbor both essential oil and water-soluble components of a plant. Due to the dispersion of the light amount of essence through the AWs, they have their specific pleasant smell, taste, and medicinal properties. In Iranian traditional medicine, Trachyspermum ammi AW is used to treat gastrointestinal disorders. The present study was conducted to determine the chemical composition of the essential oil extracted from T. ammi AW and its antifungal activities against Candida species.Materials and Methods: The composition of the essential oil extracted from T. ammi AW was analyzed by gas chromatography-mass spectrometry. In addition, the evaluation of the antifungal activity of AW against Candida species was performed using broth microdilution methods as recommended by the Clinical Laboratory Standard Institute. Moreover, the biofilm formation inhibition, antioxidant properties, and experimental activity of AW were determined in an animal model.Results: According to the results, thymol (78.08%) was the major compound of EO, followed by carvacrol (8.20%) and carvotanacetone (6.50%). Furthermore, T. ammi AW exhibited antifungal activities against the examined fungi and inhibited the biofilm formation of C. albicans at a concentration of up to 0.25 V/V. Histopathological analyses revealed that Candida colonization declined in the mice following the administration ofT. ammi AW in a therapeutic trial.Conclusion: It seems that the presence of phenolic monoterpenes in AW has resulted in antifungal effects. Pleasant odor and antioxidant properties are extra bonuses to the antimicrobial effects of this plant. Based on the findings, AW might have the potential to be used in the management of alimentary candidiasis or oral hygienic products.

An experimental investigation and fractal modeling on the effective thermal conductivity of novel autoclaved aerated concrete (AAC)-based composites with silica aerogels (SA)

Improving the thermal insulating performance of porous building material is of great practical significance for energy-efficient buildings. In this work, silica aerogels (SA) having ultralow thermal conductivity were incorporated into autoclaved aerated concrete (AAC) via physical solution impregnation method to further improving its thermal insulating performance. As expected, the addition of SA lowers the thermal conductivity of the composites and the improvement in thermal insulating performance depends on porosity of the pristine AAC. At the SA loading of ~7 wt.%, the highest relative improvement was found to be nearly 30%. Two types of fractal models, i.e., parallel and serial, were established to predict the thermal conductivity of the SA-AAC composites. It was observed that the serial model could match well with the experiment data of the AAC-300 and AAC-400-based composites. A hybrid model of the two types was proposed so as to predict the data for the composites more satisfactorily. This modeling effort helped us better understand the role of the impregnated SA on the heat conduction mechanisms in the composites. As an extra bonus, the compressive strength and the capillary water absorption coefficient of the composites were found to increase and decrease slightly, respectively, with increasing the SA content. The lower water absorptivity indicates a better potential durability. The results shed light on the great potential of such composites in real-world applications if the cost issue can be addressed by future advances in materials fabrication technologies.

Online Quality-Aware Incentive Mechanism for Mobile Crowd Sensing with Extra Bonus

Mobile crowd sensing is a new paradigm that enables smart mobile devices to collect and share various types of sensing data in urban environments. However, new challenges arise: one is how to evaluate the quality of data each mobile user potentially is capable of providing; another is how to allocate a satisfactory yet profitable amount of reward to mobile users in order to keep them participating in crowd sensing tasks. In this paper, we first introduce a mathematical model for characterizing quality of sensing data to be contributed by mobile users. Then, we present a utility function and formulate an optimization problem for the platform, who recruits participants to contribute sensing data, to maximize the amount of high quality sensing data under a limited task budget. We next present an effective and quality-aware incentive mechanism to solve this problem for online scenarios where participants may arrive or leave at any random time. Moreover, the proposed incentive mechanism allows the platform to provide selected participants with an extra bonus according to task completion level and their previous performance to motivate them further. We formally show the proposed mechanism has the desirable properties of truthfulness, individual rationality, budgetary feasibility, and computational efficiency. We compare the proposed scheme with existing methods via simulation using a real dataset. Extensive simulation results well justify the effectiveness and robustness of the proposed approach, e.g, compared with another online method “OMG”, the gap to the optimum for our proposed Online-QIM approach is reduce by 33.3 percent when budget $B = 1000$B=1000.

Educational Planning and Human Resource Management: A Study of Public and Private Schools in Pakistan

Planning and management of curriculum and human resources in schools is precisely liable and precarious in nature. The present study addressed the matter while exploring the practices of educational planning and human resource management in public and private primary level schools in Punjab, Pakistan. The case studies of two public and private schools in Rawalpindi District of Punjab Province were conducted by interviewing the mangers and principles of private and public school respectively. The participant observations were also taken to substantiate the information provided by the respondents. The schools were selected on the basis of their reputation and high enrollment of the students. The findings of the study elaborated the differences in public and private schools with respect to educational planning and managing human resource. The public schools followed the standard curriculum designed by the Punjab text book board which is universal for all the public schools. The teachers are mostly on permanent position and experienced. Whereas in the private schools, international level curriculum is followed this differs from school to school. Every private school has their own curriculum which they followed according to the standard of the school. The manager of the school generally decides the nature of the curriculum and recruitment of the teacher on its own will and interests. The medium of instruction is English in private schools, while public school used both national and international language. As far as teacher competence is concern, the public school teachers are more experienced as compare to private schools as they are working at the same school for a longer time period due to which better able to manage various task in the school and also take part in educational planning. On the other hand, in private school, fresh and most of the time untrained young females are hired. For these employees, professional development and retention is very important for the managers. Selecting and recruiting new teacher is very tedious job as well as it also affects the student’s performances and achievements. It is indicated that the owner of the private school was in continues struggle and in apprehension of hiring, and retaining their staff by providing them extra bonuses and facilities at school, such as leaves, time flexibility, and reward etc.

Strongly coupled dark energy cosmologies yielding large-mass primordial black holes

Large primordial Black Hole (PBH) formation is enhanced if strongly coupled scalar and spinor fields ($\Phi$ and $\psi$) are a stable cosmic component since the primeval radiative expansion (SCDEW models). In particular, we show that PBH formation is easier at a specific time, i.e., when the asymptotic mass $m_H$, acquired by the $\psi$ field at the higgs scale, becomes dominant, so that the typical BH mass $M_{BH}$ depends on $m_H$ value. For instance, if $m_H \sim 100\,$ eV $(1$ keV$)$ and the coupling $\beta \sim 8.35 (37)$, PBH with $M_{BH} \simeq 10^7-10^8 $ $(10^3-10^4)\, M_\odot$ could form. The very mechanism enhancing PBH formation also causes technical difficulties to evaluate the transfer function of SCDEW models at high $k$. A tentative solution of this problem leaves only minor discrepancies from $\Lambda$CDM, also at these scales, gradually vanishing for greater $m_H$ values. We conclude that, for suitable parameter choices, SCDEW models could be the real physics underlying $\Lambda$ CDM, so overcoming its fine tuning and coincidence problems, with the extra bonus of yielding large BH seeds.

An Easily Implemented, Block-Based Fast Marching Method with Superior Sequential and Parallel Performance

The fast marching method is well known for its worst-case optimal computational complexity in solving the Eikonal equation, and it has been employed in numerous scientific and engineering fields. However, it has barely benefited from fast-advancing multicore and many-core architectures because of the challenges presented by its apparent sequential nature. In this paper, we present a straightforward block-based approach for a highly scalable parallelization of the fast marching method on shared-memory computers. Central to our new algorithm is a simplified restarted narrow band strategy, which is used to replace the global bound for terminating the front marching by an incremental bound that increases by a given stride in each restart. Our algorithm greatly reduces load imbalance among blocks through a synchronized exchanging step after the marching step. Furthermore, simple activation mechanisms are introduced to skip blocks not involved in either step. Thus the new algorithm mainly consists of two loops, each for performing one step on a group of blocks. Notably, it does not contain any data race conditions, which is ideal for a direct loop level parallelization using multiple threads. A systematic performance study is carried out for several point source problems with various speed functions on grids with up to $1024^3$ points using two different computers. Substantial parallel speedups, e.g., up to 3--5 times the number of cores on a 16-core/32-thread computer and up to 2 orders of magnitude on a 64-core/256-thread computer, are demonstrated with all cases. As an extra bonus, our new algorithm also gives much improved sequential performance in most scenarios. Detailed pseudocodes are provided to illustrate the modification procedure from the single-block to the multiblock sequential algorithm in a step-by-step manner.

Incentivizing Learning-by-Doing: The Role of Compensation Schemes

In this paper, we examine the impact of pay-for-performance incentives on learning-by-doing. We exploit personnel data on fruit pickers paid under two distinct compensation contracts: a standard piece rate plan and a piece rate plan with an extra one-time bonus tied to output. Under the bonus contract, we observe bunching of performance just above the bonus threshold, suggesting workers distort their behavior in response to the discrete bonus. Such bunching behavior increases as workers gain experience. At the same time, the bonus contract induces considerable learning-by-doing for workers throughout the productivity distribution, and these improvements significantly outweigh the losses to the firm from the distortionary bunching. In contrast, under the standard piece rate contract, we find minimal evidence of bunching and only small performance improvements at the bottom of the productivity distribution. Our results suggest that contract design can help foster learning on the job. This underscores the importance of dynamic considerations in principal-agent models.