Oblikovanje jestivih filmova iz proteina soje unakrsnim vezivanjem transglutaminazom iz bakterije Streptomyces

Soybean protein isolate (SPI) was used in the investigation of the formation of edible protein films through an enzymatic cross-linking method with a purified microbial transglutaminase (MTG) produced from a new effective strain Streptomyces sp. WZFF.L-M1 preserved in our laboratory, followed by the addition of glycerol and suitable heating and drying treatments. Cheaper partially-purified skimmed soybean protein powder (SSP) and whey protein isolates (WPI) were used as the substitutes partially replacing the expensive SPI products, and purified β-lactoglobulin was taken as the positive control of WPI. As a result, the three alternatives could also form highly efficient edible films under the optimal operation conditions. The films made with SPI alternatives, about 50 µm thin, had homogenous network structures, without any holes by direct observation with the naked eye. The tests of the properties of these films showed that they had high water-keeping capacity and strong elasticity, that the ultimate tensile strength (TS) and the elongation at break (Eb) had been remarkably increased (TS>5 MPa, Eb>50 %), and that the prevention rates against the permeability of water vapour and oxygen in the air were also upgraded more than 85 and 70 %, respectively.Izolat proteina soje upotrijebljen je pri oblikovanju jestivih filmova metodom unakrsnog vezivanja transglutaminaze iz novoga soja bakterije Streptomyces sp. WZFF.L-M1, uzgojenog u našem laboratoriju. Nakon dodavanja glicerola, film je zagrijan te osušen. Dio skupih izolata proteina soje zamijenjen je jeftinijim, djelomično pročišćenim obranim prahom proteina soje i izolatima proteina surutke, a pročišćenim β-laktoglobulinom dokazana je prisutnost izolata proteina surutke. Rezultati su pokazali da se u optimalnim uvjetima, upotrebom triju zamjenskih izolata, mogu proizvesti vrlo učinkoviti jestivi filmovi. Struktura filmova debljine oko 50 µm, dobivenih uporabom zamjenskih izolata, bila je homogena, bez okom vidljivih rupica. Rezultati ispitivanja pokazali su veliku moć zadržavanja vode i elastičnost tih filmova. Znatno je povećana granična čvrstoća (>5 MPa) i istezljivost (>50 %) te smanjena njihova propusnost na vodenu paru za 85 % i kisika za 70 %

The Search for Benchmarks: When Do Crowds Provide Wisdom?

We compare the performance of a comprehensive set of alternative peer identification schemes used in economic benchmarking. Our results show the peer firms identified from aggregation of informed agents' revealed choices in Lee, Ma, and Wang (2014) perform best, followed by peers with the highest overlap in analyst coverage, in explaining cross-sectional variations in base firms' out-of-sample: (a) stock returns, (b) valuation multiples, (c) growth rates, (d) R&D expenditures, (e) leverage, and (f) profitability ratios. Conversely, peers firms identified by Google and Yahoo Finance, as well as product market competitors gleaned from 10-K dis-closures, turned in consistently worse performances. We contextualize these results in a simple model that predicts when information aggregation across heterogeneously informed individuals is likely to lead to improvements in dealing with the problem of economic benchmarking

Golden Parachutes and the Wealth of Shareholders

Golden parachutes (GPs) have attracted substantial attention from investors and public officials for more than two decades. We find that GPs are associated with higher expected acquisition premiums and that this association is at least partly due to the effect of GPs on executive incentives. However, we also find that firms that adopt GPs experience negative abnormal stock returns both during and subsequent to the period surrounding their adoption. This finding raises the possibility that even though GPs facilitate some value-increasing acquisitions, they do have, on average, an overall negative effect on shareholder wealth; this effect could be due to GPs weakening the force of the market for control and thereby increasing managerial slack, and/or to GPs making it attractive for executives to go along with some value-decreasing acquisitions that do not serve shareholders' long-term interests. Our findings have significant implications for ongoing debates on GPs and suggest the need for additional work identifying the types of GPs that drive the identified correlation between GPs and reduced shareholder value

Evaluating Firm-Level Expected-Return Proxies

We develop and implement a rigorous analytical framework for empirically evaluating the relative performance of firm-level expected-return proxies (ERPs). We show that superior proxies should closely track true expected returns both cross-sectionally and over time (that is, the proxies should exhibit lower measurement-error variances). We then compare five classes of ERPs nominated in recent studies to demonstrate how researchers can easily implement our two-dimensional evaluative framework. Our empirical analyses document a tradeoff between time-series and cross-sectional ERP performance, indicating the optimal choice of proxy may vary across research settings. Our results illustrate how researchers can use our framework to critically evaluate and compare a growing body of ERPs

Reexamining staggered boards and shareholder value

Cohen and Wang (2013) (CW2013) provide evidence consistent with market participants perceiving staggered boards to be value reducing. Amihud and Stoyanov (2016) (AS2016) contests these findings, reporting some specifications under which the results are not statistically significant. We show that the results retain their significance under a wide array of robustness tests that address the concerns expressed by AS2016. Our empirical findings reinforce the conclusions of CW2013

Economic Uncertainty and Earnings Management

In the presence of managerial short-termism and asymmetric information about skill and effort provision, firms may opportunistically shift earnings from uncertain to more certain times. We document that firms report more negative discretionary accruals when financial markets are less certain about their future prospects. Stock-price responses to earnings surprises are moderated when firm-level uncertainty is high, consistent with performance being attributed more to luck rather than skill and effort, which can create incentives to shift earnings toward lower-uncertainty periods. We show that the resulting opportunistic earnings management is concentrated in CEOs, firms, and periods where such incentives are likely to be strongest: (1) where CEO wealth is sensitive to change in the share price, (2) where announced earnings are particularly likely to be an important source of information about managerial ability and effort, and (3) before implementation of Sarbanes-Oxley made opportunistic earnings management more challenging. Our evidence highlights a novel channel through which uncertainty affects managerial decision making in the presence of agency conflicts

Short-Termism and Capital Flows

During the period 2005-2014, S&P 500 firms distributed to shareholders more than $3.95 trillion via stock buybacks and$2.45 trillion via dividends―6.4 trillion in total. These shareholder payouts amounted to over 93% of the firms' net income. Academics, corporate lawyers, asset managers, and politicians point to such shareholder-payout figures as compelling evidence that “short-termism" and “quarterly capitalism" are impairing firms' ability to invest, innovate, and provide good wages. We explain why S&P 500 shareholder-payout figures provide a misleadingly incomplete picture of corporate capital flows and the financial capacity of U.S. public firms. Most importantly, they fail to account for offsetting equity issuances by firms. We show that, taking into account issuances, net shareholder payouts by all U.S. public firms during the period 2005-2014 were in fact only about 2.50 trillion, or 33% of their net income. Moreover, much of these net shareholder payouts were offset by net debt issuances, and thus effectively recapitalizations rather than firm-shrinking distributions. After excluding marginal debt capital inflows, net shareholder payouts by public firms during the period 2005-2014 were only about 22% of their net income. In short, S&P 500 shareholder-payout figures are not indicative of actual capital flows in public firms, and thus cannot provide much basis for the claim that short-termism is starving public firms of needed capital. We also offer three other reasons why corporate capital flows are unlikely to pose a problem for the economy