Ocean acidification in the aftermath of the Marinoan glaciation

Boron isotope patterns preserved in cap carbonates deposited in the aftermath of the younger Cryogenian (Marinoan, ca. 635 Ma) glaciation confirm a temporary ocean acidification event on the continental margin of the southern Congo craton, Namibia. To test the significance of this acidification event and reconstruct Earth’s global seawater pH states at the Cryogenian-Ediacaran transition, we present a new boron isotope data set recorded in cap carbonates deposited on the Yangtze Platform in south China and on the Karatau microcontinent in Kazakhstan. Our compiled δ11B data reveal similar ocean pH patterns for all investigated cratons and confirm the presence of a global and synchronous ocean acidification event during the Marinoan deglacial period, compatible with elevated postglacial pCO2 concentrations. Differences in the details of the ocean acidification event point to regional distinctions in the buffering capacity of Ediacaran seawater

Examining the Influence of Selectivity on Alumni Giving at Public Universities: A Dynamic Panel Modeling Approach

This study examines the influence of institutional selectivity on alumni giving among public research universities, using a conceptual framework based on the economics of nonprofit organizations. This study introduces a dynamic panel modeling technique, which addresses many limitations that more traditional statistical models have when applied to panel data with lagged or "dynamic" variables. Using panel data from 147 public universities over 11 years, the analysis for this study compares the results from ordinary least squares (OLS), fixed effects, and instrumental variable (2SLS) regression with a dynamic fixed effects panel model using a procedure proposed by Blundell and Bond (1998). This dynamic panel modeling technique allows researchers to simultaneously discern the relationship between variables and take into account the possible endogeneity and omitted variable biases, as well as determine conditional convergence or divergence of the values of key observed variables over time. The results indicate that ordinary least squares, fixed effects, and instrumental variable regression models yield different coefficients, standard errors, and probability values for hypothesis tests. Results from the most robust technique, a dynamic panel fixed effects model using system generalized method of moments, did not indicate that a statistically significant relationship exists between student selectivity and alumni giving. However, the presence of a law or medical program and institutional wealth were statistically significant. Additionally, there is no evidence of convergence or divergence of alumni giving rates. The results from this analysis have a number of implications. First, the statistically insignificant relationship between selectivity and alumni giving challenges a major paradigm in the literature regarding the influence of this measure of prestige on alumni giving. Future studies should test the influence of other conceptions of prestige and donative support, using dynamic panel modeling, to see if the results are similar. Second, this analysis shows that statistical models prominent in the literature can yield misleading results when applied to panel data. Researchers, therefore, must take great care in using the most appropriate technique when examining dynamic panel data. Finally, this analysis indicates that more complex modeling techniques are required to study alumni giving over time.</p

Popular Discontents: The Historical Roots of Italian Right Wing Populism

Emerging from the ashes of the old electoral system of the First Republic, an ideological populism built on regional identity, most significantly espoused by the Lega Nord political party, became a dominant force in Italian politics. This populism initially attacked a corrupt state, but evolved to confront perceived threats to its homeland region, such as globalization and immigration. Despite these developments, this populism continues to create a discourse which pits a virtuous, homogenous people against a set of self-serving poteri forti (powers that be). What self-serving powers gave rise to this populism? This anti-state, xenophobic populism exists as a response to a “negative aggregation” of political, social, and economic conjunctures systemic to Italian politics since its formation as a republic in 1861. It is clear that specific elements of contemporary Italian state formation and political economy gave rise to this populism and sustained its particular ideological construction. Thus this investigation traces these forces that have allowed Lega and the populism it embodies to emerge politically at the end of Italy’s First Republic

Normal Forms and Equivalence of K-periodically Routed Graphs

We introduce K-periodically Routed Graphs, which are extensions of Marked Graphs with routing nodes, governed by ultimately periodic binary sequences. We study data relations and dependencies, as well as equational transformations of the network topology. We show the existence of expanded normal forms. We prove that some transformations preserve external flow equivalence. Issues arising from internal flow interleavings and permutations are also tackled

The disentangling power of unitaries

We define the disentangling power of a unitary operator in a similar way as the entangling power defined by Zanardi et al. [P. Zanardi, C. Zalka, L. Faoro, Phys. Rev. A 62 (2000) 030301(R), quant-ph/0005031]. A general formula is derived and it is shown that both quantities are directly proportional. All results concerning the entangling power can simply be translated into similar statements for the disentangling power. In particular, the disentangling power is maximal for certain permutations derived from orthogonal Latin squares. These permutations can therefore be interpreted as those that distort entanglement in a maximal way

Dietary alterations modulate the microRNA 29/30 and IGF-1/AKT signaling axis in breast Cancer liver metastasis.

Background: Metastatic cancer is incurable and understanding the molecular underpinnings is crucial to improving survival for our patients. The IGF-1/Akt signaling pathway is often impaired in cancer leading to its progression and metastases. Diet modification is known to alter the IGF-1/Akt pathway and affect the expression of microRNA involved in tumor initiation, growth and metastases. Liver metastases are one of the most common type of metastases in breast and colon cancer. In the present study, we looked at the effect of diet modification on the expression of microRNA in normal liver and liver with breast cancer metastases using in vivo model. Methodology: 6-month-old C57BL/6 J mice were put on either an ad libitum (AL) diet, or 40% calorie restricted (CR) diet or were fasted for 24 h (FA) before sacrifice. MicroRNA array analysis, western blot and qRT-PCR were performed using liver tissue to compare the treatment groups. A breast cancer model was also used to study the changes in microRNA expression in liver of a group of BALB/c mice orthotopically injected with 4 T1 cells in the mammary fat pad, put on either an AL or 30% CR diet. Liver and primary tumor tissues were used to perform qRT-PCR to compare the treatment groups. Results: MicroRNA array analysis showed significant changes in miRNA expression in both CR and FA conditions in normal liver. Expression of miR-29 and miR-30 family members was increased in both CR and FA. Western blot analysis of the normal liver tissue showed that CR and FA downregulated the IGF-1/Akt pathway and qRT-PCR showed that the expression of miR-29b, miR-29c, miR-30a and miR-30b were increased with CR and FA. Liver tissue collected from mice in the breast cancer model showed an increase in expression of miR-29b, miR-29c and miR-30b while tumor tissue showed increased expression of miR-29c, miR-30a and miR-30b. Discussion: Members of the miR-29 family are known to target and suppress IGF-1, while members of the miR-30 family are known to target and suppress both IGF-1 and IGF-1R. In the present study, we observe that calorie restriction increased the expression of miR-29 and miR-30 in both the normal liver as well as the liver with breast cancer metastases. These findings suggest that dietary alterations may play a role in the treatment of liver metastasis, which should be evaluated further

Unbiased approximations of products of expectations

We consider the problem of approximating the product of n expectations with respect to a common probability distribution μ⁠. Such products routinely arise in statistics as values of the likelihood in latent variable models. Motivated by pseudo-marginal Markov chain Monte Carlo schemes, we focus on unbiased estimators of such products. The standard approach is to sample N particles from μ and assign each particle to one of the expectations; this is wasteful and typically requires the number of particles to grow quadratically with the number of expectations. We propose an alternative estimator that approximates each expectation using most of the particles while preserving unbiasedness, which is computationally more efficient when the cost of simulations greatly exceeds the cost of likelihood evaluations. We carefully study the properties of our proposed estimator, showing that in latent variable contexts it needs only O(n) particles to match the performance of the standard approach with O(n^2) particles. We demonstrate the procedure on two latent variable examples from approximate Bayesian computation and single-cell gene expression analysis, observing computational gains by factors of about 25 and 450, respectively

Identification of Functional Maintenance Regions of Golf Courses in the United States

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Spatial Parkin Translocation and Degradation of Damaged Mitochondria via Mitophagy in Live Cortical Neurons

SummaryMitochondria are essential for neuronal survival and function. Proper degradation of aged and damaged mitochondria through mitophagy is a key cellular pathway for mitochondrial quality control. Recent studies have indicated that PINK1/Parkin-mediated pathways ensure mitochondrial integrity and function [1–8]. Translocation of Parkin to damaged mitochondria induces mitophagy in many nonneuronal cell types [9–16]. However, evidence showing Parkin translocation in primary neurons is controversial [9, 15, 17, 18], leaving unanswered questions as to how and where Parkin-mediated mitophagy occurs in neurons. Here, we report the unique process of dissipating mitochondrial Δψm-induced and Parkin-mediated mitophagy in mature cortical neurons. Compared with nonneuronal cells, neuronal mitophagy is a much slower and compartmentally restricted process, coupled with reduced anterograde mitochondrial transport. Parkin-targeted mitochondria are accumulated in the somatodendritic regions where mature lysosomes are predominantly located. Time-lapse imaging shows dynamic formation and elimination of Parkin- and LC3-ring-like structures surrounding depolarized mitochondria through the autophagy-lysosomal pathway in the soma. Knocking down Parkin in neurons impairs the elimination of dysfunctional mitochondria. Thus, our study provides neuronal evidence for dynamic and spatial Parkin-mediated mitophagy, which will help us understand whether altered mitophagy contributes to pathogenesis of several major neurodegenerative diseases characterized by mitochondrial dysfunction and impaired transport