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Ceramide synthases catalyze anN-acyltransferase reaction using fatty acyl-coenzyme A (CoA) and long-chain base (LCB) substrates to form the sphingolipid ceramide backbone and are targets for inhibition by the mycotoxin fumonisin B₁ (FB₁). Arabidopsis (Arabidopsis thaliana) contains three genes encoding ceramide synthases with distinct substrate specificities:LONGEVITY ASSURANCE GENE ONE HOMOLOG1(LOH1; At3g25540)- andLOH3(At1g19260)-encoded ceramide synthases use very-long-chain fatty acyl-CoA and trihydroxy LCB substrates, andLOH2(At3g19260)-encoded ceramide synthase uses palmitoyl-CoA and dihydroxy LCB substrates. In this study, complementary DNAs for each genewere overexpressed to determine the role of individual isoforms in physiology and sphingolipid metabolism. Differences were observed in growth resulting fromLOH1andLOH3overexpression compared withLOH2overexpression.LOH1- andLOH3-overexpressing plants had enhanced biomass relative to wild-type plants, due in part to increased cell division, suggesting that enhanced synthesis of very-long-chain fatty acid/trihydroxy LCB ceramides promotes cell division and growth. Conversely,LOH2overexpression resulted in dwarfing.LOH2overexpression also resulted in the accumulation of sphingolipids with C16 fatty acid/dihydroxy LCB ceramides, constitutive induction of programmed cell death, and accumulation of salicylic acid, closely mimicking phenotypes observed previously in LCB C-4 hydroxylase mutants defective in trihydroxy LCB synthesis. In addition,LOH2- andLOH3-overexpressing plants acquired increased resistance to FB₁, whereasLOH1-overexpressing plants showed no increase in FB₁ resistance, compared with wild-type plants, indicating thatLOH1ceramide synthase is most strongly inhibited by FB₁. Overall, the findings described here demonstrate that overexpression of Arabidopsis ceramide synthases results in strongly divergent physiological and metabolic phenotypes, some of which have significance for improved plant performance.

Traditional retailers are closing down their brick and mortar stores and increasing investments in their online channels. This may not be a beneficial strategy for retailers selling nondigital products, such as apparel, which customers prefer to physically evaluate to make the purchase decision. In such product categories, retailers’ physical stores could influence the sales on its online channel. We utilize the event of store opening by a large apparel retailer and use customer-level data to examine the effect of store presence on the online purchase behavior of its existing customers. We find that the retailer’s store openings resulted in an increase in online purchases from such customers for two reasons. First, higher store interactions engaged customers with the retailer’s brand, which resulted in their higher online purchases. Second, customers could freely purchase apparel from the retailer’s online channel, because they had the option to return it at a nearby store if it did not fit their expectations. Multichannel retailers should organize store events to engage customers and design lenient return policies to reduce the risk of purchase from online channel. We utilize the event of store opening by a large apparel retailer and use customer-level data to estimate the effect of store presence on the online purchase behavior of its existing customers. We find that the retailer’s store openings resulted in an increase in online purchases from such customers. Drawing on the theory of planned behavior and prospect theory, we propose two mechanisms to explain this complementary effect of store presence on online purchases by existing customers. These mechanisms are the store engagement effect —customers making higher online purchases because of higher engagement from store interactions—and the store return effect —reduced risk of online purchase because of the option of store returns. We provide direct empirical evidence of these mechanisms on customer-level data. We further show that these effects increase as customers’ distances from the retailer’s store reduce because of the store openings. Our findings have significant implications for multichannel retailers. The online appendices are available at https://doi.org/10.1287/isre.2018.0814 .

Supernumerary teeth are the teeth present in addition to the normal set of teeth and are not uncommon in the general population. Presence of supernumerary teeth may affect the aesthetics of an individual and hence need appropriate management. It is however rare to find multiple supernumerary teeth which are not associated with any syndromes. Non-syndromic multiple supernumerary teeth have a predilection to occur in the mandibular premolar region. This paper reports an unusual case of an 18 year old boy with two completely erupted additional premolars on either side of the mandibular arch.

Customers often evaluate products at brick-and-mortar stores to identify their “best-fit” product but buy it for a lower price at a competing online retailer. This free-riding behavior by customers is referred to as “showrooming,” and we show that this is detrimental to the profits of the brick-and-mortar stores. We first analyze price matching as a short-term strategy to counter showrooming. Price matching allows customers to purchase a product from the store for less than the store’s posted price, so one would expect the price matching strategy to be less effective as the fraction of customers who seek the matching increases. However, our results show that with an increase in the fraction of customers who seek price matching, the store’s profits initially decrease and then increase. While price matching could be used even when customers do not exhibit showrooming behavior, we find that it is more effective when customers do showrooming. We then study exclusivity of product assortments as a long-term strategy to counter showrooming. This strategy can be implemented in two different ways: (1) by arranging for exclusivity of known brands (e.g., Macy’s has such an arrangement with Tommy Hilfiger) or (2) through the creation of store brands at the brick-and-mortar store (T. J. Maxx sells a large number of store brands). Our analysis suggests that implementing exclusivity through store brands is better than exclusivity through known brands when the product category has few digital attributes. However, when customers do not showroom, the known-brand strategy dominates the store-brand strategy. The online appendix is available at https://doi.org/10.1287/mnsc.2017.2764 . This paper was accepted by Chris Forman, information systems.

In this paper, we extend the understanding of versioning strategy of an information goods monopolist and provide new insights on when versioning is optimal. To do so, we derive the optimal product line or versions of an information good and the corresponding prices. By relaxing common assumptions on consumers’ usage costs, versioning costs and capital research and development costs, we provide new insights as well as reconcile extant findings on versioning. For a good with no-free-disposal (NFD), i.e., one where consumers have usage costs, our results show that a monopolist’s marginal cost and consumers’ usage costs have the same impact on its versioning strategy, and that these factors are the sole reason for optimality of versioning of information goods. By endogenizing the production of the highest-quality, we show that capital costs create a downward distortion of quality even for the highest types in the market even under full information. Presence of separate versioning costs also lowers the qualities served to the high types and reduces the segment of consumers who are served with product versions. However, versioning costs do not affect market coverage or the price-quality menu itself. Further, when some of the consumer usage costs are absorbed by the firm (as in case of cloud-based provisioning), it does not necessarily lead to market expansion. This paper was accepted by Chris Forman, information systems.

The rapid pace of technological innovation necessitates that information technology (IT) services firms continually invest in replenishing the skills of their key asset base, the human capital. We examine whether human capital investments directed toward employee training are effective in improving employee performance. Our rich employee level panel data set affords us the opportunity to link formal training with performance at the individual employee level. Using a dynamic panel model, we identify a significant positive impact of training on employee performance. A unit increase in training is linked to a 2.14% increase in an employee's performance. Interestingly, we find that in the IT sector, skills atrophy and consequently high-experience employees reap higher returns from training, which highlights the uniquely dynamic nature of IT knowledge and skills. We also find that general training that an employee can utilize outside the focal firm improves employee performance. However, specific training pertinent to the focal firm is not positively linked to performance. On the other hand, although domain and technical training both enhance employee performance individually, the interaction between the two suggests a substitutive relationship. Thus, our findings suggest that the value of training is conditional on a focused curricular approach that emphasizes a structured competency development program. Our findings have both theoretical and practical significance. Most important, they justify increased human capital investments to fuel future growth in this important component of the global economy. This paper was accepted by Lorin Hitt, information systems.

Multisourcing, the practice of stitching together best-of-breed IT services from multiple, geographically dispersed service providers, represents the leading edge of modern organizational forms. While major strides have been achieved in the last decade in the information systems (IS) and strategic management literature in improving our understanding of outsourcing, the focus has been on a dyadic relationship between a client and a vendor. We demonstrate that a straightforward extrapolation of such a dyadic relationship falls short of addressing the nuanced incentive-effort-output linkages that arise when multiple vendors, who are competitors, have to cooperate and coordinate to achieve the client's business objectives. We suggest that when multiple vendors have to work together to deliver end-to-end services to a client, the choice of formal incentives and relational governance mechanisms depends on the degree of interdependence between the various tasks as well as the observability and verifiability of output. With respect to cooperation, we find that a vendor must not only put effort in a \"primary\" task it is responsible for but also cooperate through \"helping\" effort in enabling other vendors perform their primary tasks. In the context of coordination, we find that task redesign for modularity, OLAs, and governance structures such as the guardian vendor model represent important avenues for further research. Based on the analysis of actual multisourcing contract details over the last decade, interviews with leading practitioners, and a review of the single-sourcing literature, we lay a foundation for normative theories of multisourcing and present a research agenda in this domain.

The introduction of product upgrades in a competitive environment is commonly observed in the software industry. When introducing a new product, a software vendor may employ behavior-based price discrimination (BBPD) by offering a discount over its market price to entice existing customers of the competitor. This type of pricing is referred to as competitive upgrade discount pricing and is possible because the vendor can use proof of purchase of a competitor's product as credible evidence to offer the discount. At the same time, the competitor may offer a discount to its own previous customers in order to induce them to buy its upgrade. We formulate a game-theoretic model involving an incumbent and entrant where both firms can offer discounts to existing customers of the incumbent. Although several equilibrium possibilities exist, we establish that an equilibrium with competitive upgrade discount pricing is observed only for a unique market structure and a corresponding unique set of prices. In this equilibrium, instead of leveraging its first mover advantage, the incumbent cedes market share to the entrant. Furthermore, the profits of both the incumbent and the entrant reduce with switching costs. This implies that the use of BBPD has product design implications because firms may influence the switching costs between their products by making appropriate compatibility decisions. In addition, lower switching costs result in reduced consumer surplus. Hence, a social planner may want to increase switching costs. The resulting policy implications are different from those prevalent in other industries such as mobile telecommunications where the regulators reduced switching costs by enforcing number portability.

The ongoing digitization of multiple industries has drastically reduced the half-life of skills and capabilities acquired by knowledge workers through formal education. Thus, firms are forced to make significant ongoing investments in training their employees to remain competitive. Existing research has not examined the role of training in improving firm-level productivity of knowledge firms. This paper provides an innovative econometric framework to estimate returns to such employee training investments made by firms. We use a panel dataset of small- to medium-sized Indian IT services firms and assess how training enhances human capital, a critical input for such firms, thereby improving firm revenues. We use econometric approaches based on optimization of the firm’s profit function to eliminate the endogenous choice of inputs common in production function estimations. We find that an increase in training investments is significantly linked to an increase in revenue per employee. Further, marginal returns to training are increasing firm size. Therefore, relatively speaking, large firms benefit more from training. For the median company in our data, we find that a dollar invested in training yields a return of $4.67, and this effect approximately grows 2.5 times for the 75th percentile-sized firm. A variety of robustness checks, including the use of data envelopment analysis, are used to establish the veracity of our results.

Multisourcing, the practice of stitching together best-of-breed IT services from multiple, geographically dispersed service providers, represents the leading edge of modern organizational forms. While major strides have been achieved in the last decade in the information systems (IS) and strategic management literature in improving our understanding of outsourcing, the focus has been on a dyadic relationship between a client and a vendor. We demonstrate that a straightforward extrapolation of such a dyadic relationship falls short of addressing the nuanced incentive-effort-output linkages that arise when multiple vendors, who are competitors, have to cooperate and coordinate to achieve the client's business objectives. We suggest that when multiple vendors have to work together to deliver end-to-end services to a client, the choice of formal incentives and relational governance mechanisms depends on the degree of interdependence between the various tasks as well as the observability and verifiability of output. With respect to cooperation, we find that a vendor must not only put effort in a \"primary\" task it is responsible for but also cooperate through \"helping\" effort in enabling other vendors perform their primary tasks. In the context of coordination, we find that task redesign for modularity, OLAs, and governance structures such as the guardian vendor model represent important avenues for further research. Based on the analysis of actual multisourcing contract details over the last decade, interviews with leading practitioners, and a review of the single-sourcing literature, we lay a foundation for normative theories of multisourcing and present a research agenda in this domain. [PUBLICATION ABSTRACT]