Contracting in the Absence of Specific Investments and Moral Hazard: Understanding Carrier-Driver Relations in U.S. Trucking

This paper considers functions of contracting other than the protection of relationship-specific investments and the provision of marginal incentives, and applies the theory to explain variation in the form of compensation of over-the-road truck drivers in the U.S. Specifically, we argue that contracts in this industry serve to economize on the costs of price determination for heterogeneous transactions. We show that the actual terms of those contracts vary systematically with the nature of hauls in a way that is consistent with the theory. By contrast, we find that vehicle ownership, which defines a driver's status as an owner operator or company driver, depends on driver, but not trailer or haul, characteristics.

Investigating the Quality Dynamics of American Aroma Hops Intended for Dry-Hopping Beer

Historically, brewers have used dry-hopping (a cold extraction of nonvolatile and volatile chemicals from hops into fermenting or finished beer) to increase the microbial stability and shelf life of their beer. As hoppy beer styles have gained in popularity over the last decade (2007-2017), the objective of dry-hopping has turned to imparting hop aroma and flavor to beer while minimizing bitterness extraction. To extract hop aroma into beer, brewers have been using extreme hopping rates (sometimes > 0.7 kg/hL, equivalent to more than 18 lb/US bbl), which are mostly driven by increases in dry-hopping rates. These addition rates may be unsustainable from an agronomic perspective, potentially wasteful due to beer losses, and suboptimal at efficiently extracting aroma from hops. Therefore, the extraction efficiencies of a number of key hop volatile and nonvolatile constituents related to hoppy beer aroma and flavor were investigated over a range of commercially relevant Cascade dry-hopping rates (0, 0.2, 0.4, 0.8, and 1.6 kg/hL). It was determined that adding more hops during dry-hopping did not simply lead to increased aroma intensity but also changes aroma quality in the finished beer. Dry-hopping rates >0.8 kg/hL had hop aromas that were more herbal/tea in quality than citrus. To maintain a more balanced hop aroma quality, the use of a static dry-hopping rate between 0.4 and 0.8 kg/hL was suggested. Also, using dry- hopping rates >0.8 kg/hL lead to diminishing returns in terms of increasing hop aroma and is an inefficient use of raw material. From 2007-2017, Cascade and Centennial hops were the most commercially important aroma varieties to the American hop and craft brewing industries. They were very popular with US (and global) brewers because of the unique aroma and flavor they impart to hop-forward beer styles, especially during dry-hopping. However, there is no scientifically-validated method to predict beer aroma intensity and quality during dry-hopping. Many brewers rely a hop’s total oil content as a measure of its aroma potential, but to date the connection between total oil content and a hop’s aromatic intensity has not been proven. Additionally, the variation that exists in the hop volatile profiles and dry-hop aroma potential within these important commercial hop varieties over a given harvest year is not documented. Over the 2014, 2015, and 2016 hop harvests a large sample of Cascade (n=51) and Centennial (n=33) hops were procured from farms throughout the Pacific Northwest (WA, ID and OR). Within each of these harvest years, significant differences were observed in the hop volatile chemical profiles and the aroma intensities/qualities that these hops attributed to beer. These results indicate that at the same static dry-hopping rate of 3.86 g/L, there were significant and measurable differences in the aroma intensity as well as the quality of aroma attributed to beer from different commercially available Cascade and Centennial samples from the same harvest year. In agreement with prior research, it was also determined that total oil content (mL oil/100g hop) did not serve as an effective predictor of dry-hop aroma performance in beer. Instead, the concentration (mg/ 100g hop) of specific hop volatiles in hydrodistilled hop oil (geraniol for Cascade and β-pinene for Centennial) served as superior indicators of dry-hop aroma performance. Strategies both on the farm and in the brewery were investigated as ways to promote or modify aroma quality and intensity during dry hopping. On the farm, the impact of harvest maturity on Cascade quality and dry-hop aroma potential was evaluated using a unique weekly sampling protocol, whereby, 5-6 samples were collected from the same location within a commercial hopyard over three consecutive harvest years. For this specific hopyard, hop aroma intensity (OHAI) and citrus quality attributed to the beer during dry-hopping increased as a function of harvest date. Total hop essential oil content and a number of different hop essential oil volatiles (notably geraniol) displayed a significant positive trend with harvest date. For the first time, concentrations of thiol precursors (mainly S-3-(hexan-1-ol)-l-cysteine) were observed to decrease over harvest, while the concentrations of free thiols (mainly 3-mercaptohexanol) increased. Taken together these findings suggests that for brewers to best utilize Cascade hops, early harvested hops might be better for bittering or kettle/whirlpool additions, while later harvested hops might be better for dry-hopping or aroma additions. In the brewery, a sensory directed study on beers dry-hopped with Cascade, Centennial, and Chinook was used to evaluate the qualitative changes in the aroma of dry-hopped beers when these hops were used individually and in different blended combinations for dry-hopping. Blending hops as opposed to dry-hopping with single varieties produced the most intense aromas. In addition, specific blends of hops were found to achieve similar aroma qualities to single varieties. Therefore, by utilizing hop blends brewers may be able to make substitutions when faced with shortages due to cost and/or quality while maintaining similar aroma profiles. Overall, the results from these studies provide hop breeders with aromatic quality and metabolite targets for creating new / replacement hop varieties that have similar aroma profiles to these important American varieties. Growers benefit by being able to fine tune growing and post-harvest processing conditions to promote the concentrations of these hop volatiles in these varieties. Finally, this research will help brewers maximize the efficiency of aroma extraction during dry-hopping and guide the development of more sustainable techniques to better utilize this raw ingredient, improve beer quality, and obtain consistent hoppy aroma in beer

Sensory Directed Mixture Study of Beers Dry-Hopped with Cascade, Centennial, and Chinook

American craft beer style and flavor is often driven by the unique qualities of American hops. Cascade, Chinook, and Centennial hops are used prominently for dry-hopping singly and/or in blends to impart an intense hoppy aroma to beer. A sensory directed dry-hopping mixture study was performed to understand the contribution that each of these hops make to beer aroma. Utilizing a 4th degree simplex-lattice mixture-design, sixteen beers were prepared (including an "unhopped" control) by dry-hopping a common "unhopped" base beer with different blends of ground whole cone hops made from the three hop cultivars. The treatments were evaluated by trained panelists using descriptive analysis, where the response variables used by the panel encompassed the sensory attributes that described the unique aromatic features of these three hops, (i.e., citrus, tropical/fruity, tropical/catty, and herbal). Using these outputs, the sensory contributions of each individual cultivar, as well as mixtures of the cultivars, were examined on a per attribute basis. These results can be used to select combinations or blends of the three hops for use during dry-hopping that provide similar or dissimilar overall aroma intensity and quality in dry-hopped beer

Impact of static dry-hopping rate on the sensory and analytical profiles of beer

Dry-hopping is a technique that has been used by brewers to increase the hop aroma and flavour of beer for centuries. Throughout the twenty first century, dry-hopping has become an increasingly popular method among craft brewers to impart intense hoppy aroma and flavour to beer. Many US craft brewers use extremely high dry-hop dosing rates of up to 2200 g/hL and this is both unsustainable and potentially wasteful. This study examines the impact of dry-hopping rate on the sensorial and analytical characteristics of dry-hopped beers. An unhopped pale beer was statically dry-hopped with whole cone Cascade from the 2015 harvest over a broad range of dry-hopping rates (200-1600 g/hL) in replicated, pilot scale (80 L) aliquots. Trained panellists using descriptive analysis scaled the overall and qualitative hop aroma intensity of these beers, as well as the unhopped base beer. Instrumental analysis was used to measure the levels of hop volatile and non-volatile extraction between the treatments. The relationship between dry-hopping rate and the sensorial and analytical characteristics of the finished beer was not linear and, based on the extraction efficiencies of select hop volatiles, had an ideal range between 400 and 800 g/hL. (C) 2018 The Institute of Brewing & Distillin

Knowledge of the signs and symptoms and risk factors of lung cancer in Australia: Mixed methods study

© 2016 Crane et al. Background: Lung cancer is the leading cause of cancer death in Australia. There is potential that health promotion about the risks and warning signs of lung cancer could be used to reduce delays in symptom presentation when symptoms are first detected. This study investigated knowledge, attitudes and beliefs which might impact help-seeking behaviour and could provide insight into possible public health interventions in New South Wales (NSW). Methods: A convergent mixed method study design was used wherein data from 16 qualitative focus groups of residents (40+ years), purposefully recruited and stratified by smoking status, age and geography (metropolitan/regional), were compared with a CATI administered population-wide telephone survey (n = 1,000) using the Cancer Research UK cancer awareness measure (LungCAM). Qualitative findings were analysed thematically using NVIVO. Logistic regression analysis was used to investigate predictors of symptom knowledge in STATA. Findings were integrated using triangulation techniques. Results: Across focus groups, haemoptysis was the only symptom creating a sense of medical urgency. Life experiences evoked a 'wait and see' attitude to any health deterioration. Perceived risk was low amongst those at risk with current smokers preferring to deny their risk while former smokers were generally unaware of any ongoing risk. The quantitative sample consisted of females (62 %), 40-65 years (53 %), low SES (53 %), former (46 %) and current smokers (14 %). In quantitative findings, haemoptysis and dyspnoea were the most recognised symptoms across the sample population. Age (<65 years), sex (female) and high socio-economic status contributed to a higher recognition of symptoms. Smoking was recognised as a cause of lung cancer, yet ever-smokers were less likely to recognise the risk of lung cancer due to second-hand smoke (OR 0.7 95 % CI 0.5-0.9). Conclusion: While there was some recognition of risk factors and symptoms indicative of lung cancer, there was disparity across the sample population. The qualitative findings also suggest that knowledge may not lead to earlier presentation; a lack of urgency about symptoms considered trivial, and smoking-related barriers such as stigma may also contribute to time delays in presentation. Public health interventions may be required to increase awareness of risk and emphasise the importance of seeking medical attention for ongoing symptoms

Vertical integration and firm boundaries : the evidence

Since Ronald H. Coase's (1937) seminal paper, a rich set of theories has been developed that deal with firm boundaries in vertical or input–output structures. In the last twenty-five years, empirical evidence that can shed light on those theories also has been accumulating. We review the findings of empirical studies that have addressed two main interrelated questions: First, what types of transactions are best brought within the firm and, second, what are the consequences of vertical integration decisions for economic outcomes such as prices, quantities, investment, and profits. Throughout, we highlight areas of potential cross-fertilization and promising areas for future work

Aroma Extract Dilution Analysis of Beers Dry-Hopped with Cascade, Chinook, and Centennial

Cascade, Chinook, and Centennial hops are used extensively throughout the brewing industry either individually or in various combinations to add hoppy aroma to beer. This high use of hops, particularly via late- or dry-hopping, creates a need to better understand the chemical contribution of these hop varieties during dry-hopping beer in order to predict brewing performance. Solvent-Assisted Flavor Evaporation (SAFE) and Aroma Extract Dilution Analysis (AEDA) was performed on unhopped beer that was dry-hopped individually with each of these varieties as well as the unhopped base. This technique was used to determine the aroma compounds that were the greatest contributors to the dry-hop character of these hops. The analysis of beer prepared with Cascade, Chinook, and Centennial identified 9, 10, and 11 character impact compounds, respectively. Commonalities were observed among the three varieties regarding 2-furanmethanol, linalool, geraniol, cis-geranic acid methyl ester, and n-decanoic acid in dry-hopped beer. Variation between the hop volatiles found to be important for Centennial and Chinook dry-hop aroma was a function of only a few character impact compounds, whereas Cascade was slightly different, anchored heavily by benzenacetaldeyde. The relative similarities and differences that these three hop cultivars attribute to beer during dry-hopping were revealed by comparing which compounds were important for the characteristic aroma profiles of these cultivars in single dry-hop beers.. This knowledge is important for brewers wishing to introduce potential replacement hops and/or reductions for these hop cultivars in the future and guide the direction of future blending studies

Impact of harvest maturity on the aroma characteristics and chemistry of Cascade hops used for dry-hopping

The impact of ripening on the dry-hop aroma potential and chemical development of Cascade hops is not well understood. Therefore, 5-6 weekly hop samples were collected over the 2014, 2015 and 2016 harvests. Concentrations of humulones did not change as a function of harvest date, while total hop essential oil content displayed significant positive trends. Concentrations of thiol precursors decreased over harvest while concentrations of free thiols increased. These weekly samples were used to dry-hop an unhopped base beer. Overall hop aroma intensity and citrus quality attributed to beer during dry-hopping increased as a function of harvest date. These results suggest that for brewers to maximize the efficiency of hop usage, early harvested Cascades might be better for bittering, while, later harvested Cascades might be better for dry-hopping or aroma additions because they attributed more intense citrusy aromas to beer and had higher concentrations of free thiols and terpene alcohols

Folding of the lysine riboswitch: importance of peripheral elements for transcriptional regulation

The Bacillus subtilis lysC lysine riboswitch modulates its own gene expression upon lysine binding through a transcription attenuation mechanism. The riboswitch aptamer is organized around a single five-way junction that provides the scaffold for two long-range tertiary interactions (loop L2–loop L3 and helix P2–loop L4)—all of this for the creation of a specific lysine binding site. We have determined that the interaction P2–L4 is particularly important for the organization of the ligand-binding site and for the riboswitch transcription attenuation control. Moreover, we have observed that a folding synergy between L2–L3 and P2–L4 allows both interactions to fold at lower magnesium ion concentrations. The P2–L4 interaction is also critical for the close juxtaposition involving stems P1 and P5. This is facilitated by the presence of lysine, suggesting an active role of the ligand in the folding transition. We also show that a previously uncharacterized stem–loop located in the expression platform is highly important for the riboswitch activity. Thus, folding elements located in the aptamer and the expression platform both influence the lysine riboswitch gene regulation

Relative Influence of Trans-Pacific and Regional Atmospheric Transport of PAHs in the Pacific Northwest, US

The relative influences of trans-Pacific and regional atmospheric transport on measured concentrations of polycyclic aromatic hydrocarbons (PAHs), PAH derivatives [Nitro- (NPAH) and Oxy-(OPAH)], organic carbon (OC), and Particulate Matter (PM) less than 2.5 μm in diameter (PM₂.₅) were investigated in the Pacific Northwest, USA in 2010-2011. Ambient high volume PM₂.₅ air samples were collected at two sites in the Pacific Northwest: 1.) Mount Bachelor Observatory (MBO) in the Oregon Cascade Range (2763 m above sea level (asl)) and 2.) Confederated Tribes of the Umatilla Indian Reservation (CTUIR) in the Columbia River Gorge (CRG) (954 m asl). At MBO, the 1,8-dinitropyrene concentration was significantly positively correlated with the time a sampled air mass spent over Asia, suggesting that this NPAH may be a good marker for trans-Pacific atmospheric transport. At CTUIR, NOx, CO₂, and SO₂ emissions from a 585 MW coal fired power plant, in Boardman OR, were found to be significantly positively correlated with PAH, OPAH, NPAH, OC, and PM₂.₅ concentrations. By comparing the Boardman Plant operational time frames when the plant was operating to when it was shut down, the plant was found to contribute a large percentage of the measured PAH (67%), NPAH (91%), OPAH (54%), PM₂.₅ (39%) and OC (38%) concentrations at CTUIR and the CRG prior to Spring 2011 and likely masked trans-Pacific atmospheric transport events to the CRG. Upgrades installed to the Boardman Plant in the spring of 2011 dramatically reduced the plant’s contribution to PAH and OPAH concentrations (by ~72% and ~40%, respectively) at CTUIR and the CRG but not NPAH, PM₂.₅ or OC concentrations