Purpose Destination marketing organizations (DMOs) use Twitter to promote attractions and special events and to build brand awareness. Tweets of a DMO spread through a complex network of connected accounts. Some of these are more influential than others due to their position within the network. This paper aims to use a network analysis of 14 DMOs to identify the categories of influencers that have the greatest reach. Design/methodology/approach NodeXL was used to download and analyze network data from Twitter during July 2016 for a collection of DMOs promoting US cities. Accounts in the networks were ranked using several measures of relative influence such as the number of times the accounts mentioned/retweeted others or were mentioned in posts about the DMO. The most influential accounts in the network were identified and coded by category. Findings Media, promotional accounts and those of individuals were determined to be influential by each metric considered. Stakeholders such as hotels and restaurants occupy positions of low importance in the networks and generally do not capitalize on opportunities provided by the DMOs. Practical implications DMOs can seek out strategic partnerships with key influencers to maximize their effectiveness. Additionally, stakeholders can improve their Twitter presence by interacting with the DMOs and other influential accounts. Originality/value This paper identifies influencers that can aid in DMOs’ marketing campaigns. It also presents a methodology that can monitor the effectiveness of such campaigns, something absent in the current literature.

The earliest eutherian mammals were small-bodied locomotor generalists with a forelimb morphology that strongly resembles that of extant rats. Understanding the kinematics of the humerus, radius, and ulna of extant rats can inform and constrain hypotheses concerning typical posture and mobility in early eutherian forelimbs. The locomotion of Rattus norvegicus has been extensively studied, but the three-dimensional kinematics of the bones themselves remains under-explored. Here, for the first time, we use markerless XROMM (Scientific Rotoscoping) to explore the three-dimensional long bone movements in Rattus norvegicus during a normal, symmetrical gait (walking). Our data show a basic kinematic profile that agrees with previous studies on rats and other small therians: rats maintain a crouched forelimb posture throughout the step cycle, and the ulna is confined to flexion/extension in a parasagittal plane. However, our three-dimensional data illuminate long-axis rotation (LAR) movements for both the humerus and the radius for the first time. Medial LAR of the humerus throughout stance maintains an adducted elbow with a caudally-facing olecranon process, which in turn maintains a cranially-directed manus orientation (pronation). The radius also shows significant LAR correlated with manus pronation and supination. Moreover, we report that elbow flexion and manus orientation are correlated in R. norvegicus: as the elbow angle becomes more acute, manus supination increases. Our data also suggest that manus pronation and orientation in R. norvegicus rely on a divided system of labor between the ulna and radius. Given that the radius follows the flexion and extension trajectory of the ulna, it must rotate at the elbow (on the capitulum) so that during the stance phase its distal end lies medial to ulna, ensuring that the manus remains pronated while the forelimb is supporting the body. We suggest that forelimb posture and kinematics in Juramaia, Eomaia, and other basal eutherians were grossly similar to those of rats, and that humerus and radius LAR may have always played a significant role in forelimb and manus posture in small eutherian mammals.

We have designed and modeled new techniques, based on the 3 method, to measure thermal conductivity of liquids ͑ l ͒ and solids ͑ s ͒ under hydrostatic pressure ͑P͒. The system involves a solid sample immersed in a liquid pressure medium, both of which have unknown thermal properties. The temperature ͑T͒ and P dependance of l are first determined through the use of a modified 3 technique. This method uses a conducting wire (Pt, in this work), which is immersed in the pressure medium, as the heater/sensor. In addition to l , this allows for the accurate determination of the specific heat per volume of the liquid and Pt, ͑C͒ l and ͑C͒ Pt , respectively. The information of l and ͑C͒ l can then be used to make corrections to measurements of s , in which the sample is immersed in the pressure medium, and a metal strip acts as the heater/sensor. We present the T and P dependence of l and ͑C͒ l for the widely used pressure medium 3M Fluorinert FC77 up to 0.8 GPa. The measurement of s for a thermoelectric clathrate material, Sr 8 Ga 16 Ge 30 , in FC77 is analyzed in detail, and the refined data achieves an accuracy of 1%. The setup can be modified to measure and C up to 3.5 GPa.

The Twitter network of two academic libraries was analyzed to determine the influential accounts that connect to them. Such information can be exploited by libraries to create tailored social media outreach and information dissemination programs. Three network metrics, measuring different definitions of importance, were calculated for each account in the network. This allowed for the quantification and ranking of the accounts by influence/ importance, normally considered to be qualitative and subjective. By all measures, accounts associated with the institutions, and not faculty, staff, or students, were found to be the most influential players in the networks of both libraries, suggesting that this is a general feature of academic library Twitter networks. Furthermore, the library, as an institutional account itself, is also influential to the broader Twitter community of its home institution. This demonstrates that the library is in a key position to propagate information from sister accounts at the institution.

The existence of a negative static dielectric constant has drawn a great deal of theoretical controversy. Experimentally, one has never been observed. However, low-frequency negative capacitance has been widely reported in fields including physics, chemistry, biology, geology, and electronics. This wide variety of systems possesses an extremely diverse set of physical processes that, surprisingly, share similar characteristics. We present a general mechanism that unites the various instances of negative capacitance under a common framework. The mechanism demonstrates that the negative capacitance arises from dc/ac signal mixing across a nonlinear conductor. Verification of the model is performed in physically distinct samples: an electrorheological fluid, a fuel cell, and a solar cell. Furthermore, we argue that the negative capacitance, under appropriate conditions, can be associated with a negative-differential dielectric constant, possibly even in the static limit.