The age of digital entrepreneurship

Understanding the circumstances and reasons which facilitate digital entrepreneurship (DE) is of interest to academic research, and guides business practice, as well as public policies aiming at supporting this phenomenon given its positive impacts in terms of job creation and economic growth. We define some relevant concepts and briefly map current research using a perspective that focuses on the way digital entrepreneurs create digital value by acquiring, processing, and distributing digital information. Through the adoption of a digital information processing perspective, we provide a micro-level approach to research on digital entrepreneurship (DE) that complements existing literature on DE focused at the systemic level (digital entrepreneurship ecosystems and in the digital platforms economy). We show how these two approaches can be jointly used to identify major research streams on DE: digital business models, the digital entrepreneurship process and the creation of digital start-ups, DE in digital platforms, and entrepreneurial digital ecosystems. As is the case with existing DE frameworks, our approach concurs in putting emphasis on the new collaborative and social dynamics enabled by digital tools to support knowledge sharing and facilitate opportunity recognition

The Diversity and Abundance of Small Arthropods in Onion, Allium cepa, Seed Crops, and their Potential Role in Pollination

Onion, Allium cepa L. (Asparagales: Amaryllidaceae), crop fields grown for seed production require arthropod pollination for adequate seed yield. Although many arthropod species visit A. cepa flowers, for most there is little information on their role as pollinators. Small flower visiting arthropods (body width < 3 mm) in particular are rarely assessed. A survey of eight flowering commercial A. cepa seed fields in the North and South Islands of New Zealand using window traps revealed that small arthropods were highly abundant among all except one field. Insects belonging to the orders Diptera and Thysanoptera were the most abundant and Hymenoptera, Collembola, Psocoptera, Hemiptera, and Coleoptera were also present. To test whether small arthropods might contribute to pollination, seed sets from umbels caged within 3 mm diameter mesh cages were compared with similarly caged, hand-pollinated umbels and uncaged umbels. Caged umbels that were not hand-pollinated set significantly fewer seeds (average eight seeds/umbel, n = 10) than caged hand-pollinated umbels (average 146 seeds/umbel) and uncaged umbels (average 481 seeds/umbel). Moreover, sticky traps placed on umbels within cages captured similar numbers of small arthropods as sticky traps placed on uncaged umbels, suggesting cages did not inhibit the movement of small arthropods to umbels. Therefore, despite the high abundance of small arthropods within fields, evidence to support their role as significant pollinators of commercial A. cepa seed crops was not found

Functional Analysis of General Odorant Binding Protein 2 from the Meadow Moth, Loxostege sticticalis L. (Lepidoptera: Pyralidae)

Odorant binding proteins play a crucial role in transporting semiochemicals across the sensillum lymph to olfactory receptors within the insect antennal sensilla. In this study, the general odorant binding protein 2 gene was cloned from the antennae of Loxostege sticticalis, using reverse transcription PCR and rapid amplification of cDNA ends. Recombinant LstiGOBP2 was expressed in Escherichia coli and purified by Ni ion affinity chromatography. Real-time PCR assays indicated that LstiGOBP2 mRNA is expressed mainly in adult antennae, with expression levels differing with developmental age. Ligand-binding experiments using N-phenyl-naphthylamine (1-NPN) as a fluorescent probe demonstrated that the LstiGOBP2 protein has binding affinity to a broad range of odorants. Most importantly, trans-11-tetradecen-1-yl acetate, the pheromone component of Loxostege sticticalis, and trans-2-hexenal and cis-3-hexen-1-ol, the most abundant plant volatiles in essential oils extracted from host plants, had high binding affinities to LstiGOBP2 and elicited strong electrophysiological responses from the antennae of adults

Macroevolutionary Patterns in the Aphidini Aphids (Hemiptera: Aphididae): Diversification, Host Association, and Biogeographic Origins

, the most diverse genus in the family. We used a combined dataset of one nuclear and four mitochondrial DNA regions. A molecular dating approach, calibrated with fossil records, was used to estimate divergence times of these taxa.Most generic divergences in Aphidini occurred in the Middle Tertiary, and species-level divergences occurred between the Middle and Late Tertiary. The ancestral state of host use for Aphidini was equivocal with respect to three states: monoecy on trees, heteroecy, and monoecy on grasses. The ancestral state of Rhopalosiphina likely included both heteroecy and monoecy, whereas that of Aphidina was most likely monoecy. The divergence times of aphid lineages at the generic or subgeneric levels are close to those of their primary hosts. The species-level divergences in aphids are consistent with the diversification of the secondary hosts, as a few examples suggest. The biogeographic origin of Aphidini as a whole was equivocal, but the major lineages within Aphidina likely separated into Nearctic, Western Palearctic, and Eastern Palearctic regions.Most generic divergences in Aphidini occurred in the Middle Tertiary when primary hosts, mainly in the Rosaceae, were diverging, whereas species-level divergences were contemporaneous with diversification of the secondary hosts such as Poaceae in the Middle to Late Tertiary. Our results suggest that evolution of host alternation within Aphidini may have occurred during the Middle Tertiary (Oligocene) when the secondary hosts emerged

A cation channel in the thick ascending limb of Henle's loop of the mouse kidney: inhibition by adenine nucleotides.

1. Patch-clamp single-channel current recordings were used to study the inhibition of Ca2+-activated non-selective cation channels by internal nucleotides in patches excised from basolateral membranes of the thick ascending limb of Henle's loop of the mouse kidney. 2. The application of ATP, ADP or AMP to the cytoplasmic face of excised inside-out membrane patches reduced the open-state probability of the channels (Po) in a dose-dependent way without effect upon the unitary current amplitude. Dose-response curves gave half-maximal inhibitory concentrations of 20, 21 and 2.5 microM for ATP, ADP and AMP, respectively, while the Hill coefficient was close to one in all three cases. 3. Cyclic AMP partially inhibited channel activity (Po = 35 +/- 17% of control) only at high, unphysiological concentrations (10(-3) M) while adenosine (10(-3) M) had very little effect (Po = 83 +/- 7% of control). 4. Replacement of adenine with other purines (guanine, hypoxanthine) or pyrimidine (uridine) bases very largely reduced inhibitory activity. Cyclic GMP had no effect. 5. Non-hydrolysable analogues of ATP, AMP-PNP (10(-3) M) and ATP-gamma-S (5 x 10(-4) M), were effective inhibitors of the channel (Po = 24 +/- 7 and 9 +/- 4% of control, respectively