A Note on the Use of Debt by Venture Capital Backed Firms

Much of the current research regarding the venture capitalist examines samples of venture capital (VC) backed firms rather than the venture capitalist itself. While VC backed firms may represent the most reasonable proxy available for the study of the venture capitalist, consideration of firm-specific characteristics may need to be included to mitigate biased conclusions. Controlling for the determinants of capital structure, we examine the persistence of previously noted differences in capital structure choice and find that VC backing does not systematically alter the use of debt by firms. These results suggest that not controlling for firm specific differences when contrasting VC and non-VC backed firms may lead to inaccurate conclusions in venture capital research

Specific, Reversible Cytostatic Protection of Normal Cells Against Negative Effects of Chemotherapy

Chemotherapy is a common and effective method to treat many forms of cancer. However, treatment of cancer with chemotherapy has severe side effects which often limit the doses of therapy administered. Because some cancer chemotherapeutics target proliferating cells and tissues, all dividing cells, whether normal or tumor, are affected. Cell culture studies have demonstrated that UCN-01 is able to reversibly and selectively arrest normal dividing cells; tumor cells lines do not undergo this temporary arrest. Following UCN-01 treatment, normal cells displayed a 50-fold increase in IC50 for camptothecin; tumor cells showed no such increased tolerance. We have examined the response of the proliferating tissues of the mouse to UCN- 01 treatment, using the small bowel epithelium as a model system. Our results indicate that UCN-01 treatment can cause a cell cycle arrest in the gut epithelium, beginning 24 hours following UCN-01 administration, with cell proliferation remaining suppressed for one week. Two weeks post-UCN-01 treatment the rate of proliferation returns to normal levels. 5-FU administered during this period demonstrates that UCN-01 is able to provide protection to normal cells of the mouse within a narrow window of efficacy, from three to five days post-UCN-01. UCN-01 pretreated mice displayed improved survival, weight status and blood markers following 5-FU compared to control mice, indicating that UCN-01 can protect normal dividing tissues. The mechanism by which UCN-01 arrests normal cells in vivo was also examined. We have demonstrated that UCN-01 treatment in mice causes an increase in the G1 phase cell cycle proteins cdk4 and cyclin D, as well as the inhibitor p27. Phosphorylated Rb was also elevated in the arrested cells. These results are a departure from cell culture studies, in which inhibition of G1 phase cyclin dependent kinases led to hyposphosphorylation of Rb. Future investigation will be required to understand the mechanism of UCN-01 action. This is important information, especially for identification of alternate compounds which could provide the protection afforded by UCN-01

Combined Description of N‾N\bf{\overline{N}N} Scattering and Annihilation With A Hadronic Model

A model for the nucleon-antinucleon interaction is presented which is based on meson-baryon dynamics. The elastic part is the $G$-parity transform of the Bonn $NN$ potential. Annihilation into two mesons is described in terms of microscopic baryon-exchange processes including all possible combinations of $\pi,\eta,\rho,\omega,a_0,f_0,a_1,f_1,a_2,f_2,K,K^*$. The remaining annihilation part is taken into account by a phenomenological energy- and state independent optical potential of Gaussian form. The model enables a simultaneous description of nucleon-antinucleon scattering and annihilation phenomena with fair quality.Comment: revised version, REVTEX, 9 pages, 10 figures available from this URL ftp://ikp113.ikp.kfa-juelich.de/pub/kph140/nucl-th.9411014.u

Development and Evaluation of a Borohydride-palladium System for Selective Reduction of the C=C Bond of α,β-unsaturated Carbonyl Compounds

Selective reduction of the carbon-carbon double bond of α,β-unsaturated carbonyl compounds is most commonly and reliably effected using a palladium metal catalyst together with molecular hydrogen from a pressurized tank. Sodium borohydride, like other hydrides, is ordinarily associated with reduction of the more polarized carbonyl of such compounds. However, we have developed an alternative means of employing sodium borohydride in combination with palladium metal to selectively reduce the carbon-carbon double bonds of these compounds. In this survey study, we introduce sodium borohydride as an alternative hydrogen source for such selective, palladium-catalyzed reductions. We also compare the results of this new, heterogeneous borohydride-palladium method with that of traditional palladium-catalyzed hydrogenation. A third method using only sodium borohydride with no palladium is included for comparison.Faculty Sponsor: Dr. David B. Corde

New radiometric evidence for the age and thermal history of the metamorphic rocks of the Ruby and Nixon Fork Terranes, West-Central Alaska

https://deepblue.lib.umich.edu/bitstream/2027.42/155805/1/Dillon_et_al_1985_New_radiometric.pd

Smoking Cessation Smartphone App Use Over Time: Predicting 12-Month Cessation Outcomes in a 2-Arm Randomized Trial

BACKGROUND: Little is known about how individuals engage over time with smartphone app interventions and whether this engagement predicts health outcomes. OBJECTIVE: In the context of a randomized trial comparing 2 smartphone apps for smoking cessation, this study aimed to determine distinct groups of smartphone app log-in trajectories over a 6-month period, their association with smoking cessation outcomes at 12 months, and baseline user characteristics that predict data-driven trajectory group membership. METHODS: Functional clustering of 182 consecutive days of smoothed log-in data from both arms of a large (N=2415) randomized trial of 2 smartphone apps for smoking cessation (iCanQuit and QuitGuide) was used to identify distinct trajectory groups. Logistic regression was used to determine the association of group membership with the primary outcome of 30-day point prevalence of smoking abstinence at 12 months. Finally, the baseline characteristics associated with group membership were examined using logistic and multinomial logistic regression. The analyses were conducted separately for each app. RESULTS: For iCanQuit, participants were clustered into 3 groups: "1-week users" (610/1069, 57.06%), "4-week users" (303/1069, 28.34%), and "26-week users" (156/1069, 14.59%). For smoking cessation rates at the 12-month follow-up, compared with 1-week users, 4-week users had 50% higher odds of cessation (30% vs 23%; odds ratio [OR] 1.50, 95% CI 1.05-2.14; P=.03), whereas 26-week users had 397% higher odds (56% vs 23%; OR 4.97, 95% CI 3.31-7.52; P<.001). For QuitGuide, participants were clustered into 2 groups: "1-week users" (695/1064, 65.32%) and "3-week users" (369/1064, 34.68%). The difference in the odds of being abstinent at 12 months for 3-week users versus 1-week users was minimal (23% vs 21%; OR 1.16, 95% CI 0.84-1.62; P=.37). Different baseline characteristics predicted the trajectory group membership for each app. CONCLUSIONS: Patterns of 1-, 3-, and 4-week smartphone app use for smoking cessation may be common in how people engage in digital health interventions. There were significantly higher odds of quitting smoking among 4-week users and especially among 26-week users of the iCanQuit app. To improve study outcomes, strategies for detecting users who disengage early from these interventions (1-week users) and proactively offering them a more intensive intervention could be fruitful

Size Gap for Zero Temperature Black Holes in Semiclassical Gravity

We show that a gap exists in the allowed sizes of all zero temperature static spherically symmetric black holes in semiclassical gravity when only conformally invariant fields are present. The result holds for both charged and uncharged black holes. By size we mean the proper area of the event horizon. The range of sizes that do not occur depends on the numbers and types of quantized fields that are present. We also derive some general properties that both zero and nonzero temperature black holes have in all classical and semiclassical metric theories of gravity.Comment: 4 pages, ReVTeX, no figure

The ππ\pi \pi S-Wave in the 1 to 2 GeV Region from a ππ\pi \pi, KˉK\bar{K}K and ρρ\rho \rho(ωω\omega \omega) Coupled Channel Model

A simple $\pi \pi$, $\bar{K}K$, and $\rho \rho$($\omega \omega$) fully coupled channel model is proposed to predict the isoscalar S-wave phase shifts and inelasticities for $\pi \pi$ scattering in the 1.0 to 2.0 GeV region. The S-matrix is required to exhibit poles corresponding to the established isoscalar J$^{\pi}$ = 0$^+$ resonances f$_0$(975), f$_0$(1400), and f$_0$(1710). A dominant feature of the experimental $\pi \pi$ inelasticity is the clear opening of the $\bar{K}K$ channel near 1 GeV, and the opening of another channel in the 1.4 - 1.5 GeV region. The success of our model in predicting this observed dramatic energy dependence indicates that the effect of multi-pion channels is adequately described by the $\pi \pi$ coupling to the $\bar{K}K$ channel, the $\rho \rho$(4$\pi$) and $\omega \omega$(6$\pi$) channels.Comment: 11 pages (Revtex 3.0), 4 figs. avail. upon request, RU946

Late Paleocene Flora of the Northern Alaska Peninsula: The Role of Transberingian Plant Migrations and Climatic Change

For the first time, the Late Sagwon Flora is described from the upper beds of the Prince Creek Formation (Upper Paleocene) at the Sagavanirktok River (northern Alaska Peninsula). The flora is dominated by the angiosperm Tiliaephyllum brooksense Moiseeva et Herman sp. nov. and conifer Metasequoia occidentalis (Newb.) Chaney. The Late Sagwon Flora is most similar to the Danian or Danian-Selandian flora from the middle part of the Upper Tsagayan Subformation (Amur Region) and lower part of the Wuyun Formation (Heilongjiang Province, China). This similarity allows us to hypothesize that the genus Tiliaephyllum, which dominated in the Late Tsagayan Flora, migrated via the Bering Land Bridge from southern paleolatitudes of the Far East to high latitudes of the Arctic Pacific, due to the progressively warming climate of the Paleocene. Additional new angiosperm species are described from the Late Sagwon Flora: Archeampelos mullii Moiseeva et Herman sp. nov., Tiliaephyllum brooksense Moiseeva et Herman sp. nov., and Dicotylophyllum sagwonicum Moiseeva et Herman sp. nov

Annihilation range and final-state interaction in the antiproton-proton annihilation into pi-pi+

The large set of accurate data on differential cross section and analyzing power from the CERN LEAR experiment on $\bar pp \to \pi^+\pi^-$ in the range from 360 to 1550 MeV/c is well reproduced within a distorted wave approximation approach. The initial $\bar pp$ scattering wave functions originate from a recent $\bar N N$ model. The transition operator is obtained from a combination of the $^3P_0$ and $^3S_1$ quark-antiquark annihilation mechanisms. A good fit to the data, in particular the reproduction of the double dip structure observed in the analyzing powers, requires quark wave functions for proton, antiproton, and pions with radii slightly larger than the respective measured charge radii. This corresponds to an increase in range of the annihilation mechanisms and consequently the amplitudes for total angular momentum J=2 and higher are much larger than in previous approaches. The final state $\pi\pi$ wave functions, parameterized in terms of $\pi\pi$ phase shifts and inelasticities, are also a very important ingredient for the fine tuning of the fit to the observables.Comment: 11 pages, 11 figures (Revtex 4), revised version with one additional figure. Accepted for publication in PR