Architecture of the Nuclear Periphery of Rat Pachytene Spermatocytes: Distribution of Nuclear Envelope Proteins in Relation to Synaptonemal Complex Attachment Sites

The nucleus of spermatocytes provides during the first meiotic prophase an interesting model for investigating relationships of the nuclear envelope (NE) with components of the nuclear interior. During the pachytene stage, meiotic chromosomes are synapsed via synaptonemal complexes (SCs) and attached through both ends to the nuclear periphery. This association is dynamic because chromosomes move during the process of synapsis and desynapsis that takes place during meiotic prophase. The NE of spermatocytes possesses some peculiarities (e.g., lower stability than in somatic cells, expression of short meiosis-specific lamin isoforms called C2 and B3) that could be critically involved in this process. For better understanding of the association of chromosomes with the nuclear periphery, in the present study we have investigated the distribution of NE proteins in relation to SC attachment sites. A major outcome was the finding that lamin C2 is distributed in the form of discontinuous domains at the NE of spermatocytes and that SC attachment sites are embedded in these domains. Lamin C2 appears to form part of larger structures as suggested by cell fractionation experiments. According to these results, we propose that the C2-containing domains represent local reinforcements of the NE that are involved in the proper attachment of SCs.

Medial prefrontal cortex and self-referential mental activity: Relation to a default mode of brain function

Medial prefrontal cortex (MPFC) is among those brain regions having the highest baseline metabolic activity at rest and one that exhibits decreases from this baseline across a wide variety of goal-directed behaviors in functional imaging studies. This high metabolic rate and this behavior suggest the existence of an organized mode of default brain function, elements of which may be either attenuated or enhanced. Extant data suggest that these MPFC regions may contribute to the neural instantiation of aspects of the multifaceted “self.” We explore this important concept by targeting and manipulating elements of MPFC default state activity. In this functional magnetic resonance imaging (fMRI) study, subjects made two judgments, one self-referential, the other not, in response to affectively normed pictures: pleasant vs. unpleasant (an internally cued condition, ICC) and indoors vs. outdoors (an externally cued condition, ECC). The ICC was preferentially associated with activity increases along the dorsal MPFC. These increases were accompanied by decreases in both active task conditions in ventral MPFC. These results support the view that dorsal and ventral MPFC are differentially influenced by attentiondemanding tasks and explicitly self-referential tasks. The presence of self-referential mental activity appears to be associated with increases from the baseline in dorsal MPFC. Reductions in ventral MPFC occurred consistent with the fact that attention-demanding tasks attenuate emotional processing. We posit that both self-referential mental activity and emotional processing represent elements of the default state as represented by activity in MPFC. We suggest that a useful way to explore the neurobiology of the self is to explore the nature of default state activity.

Root Xylem Embolisms and Refilling. Relation to Water Potentials of Soil, Roots, and Leaves, and Osmotic Potentials of Root Xylem Sap1

Embolism and refilling of vessels was monitored directly by cryomicroscopy of field-grown corn (Zea mays L.) roots. To test the reliability of an earlier study showing embolism refilling in roots at negative leaf water potentials, embolisms were counted, and root water potentials (Ψroot) and osmotic potentials of exuded xylem sap from the same roots were measured by isopiestic psychrometry. All vessels were full at dawn (Ψroot −0.1 MPa). Embolisms were first seen in late metaxylem vessels at 8 am. Embolized late metaxylem vessels peaked at 50% at 10 am (Ψroot −0.1 MPa), fell to 44% by 12 pm (Ψroot −0.23 MPa), then dropped steadily to zero by early evening (Ψroot −0.28 MPa). Transpiration was highest (8.5 μg cm−2 s−1) between 12 and 2 pm when the percentage of vessels embolized was falling. Embolized vessels were refilled by liquid moving through their lateral walls. Xylem sap was very low in solutes. The mechanism of vessel refilling, when Ψroot is negative, requires further investigation. Daily embolism and refilling in roots of well-watered plants is a normal occurrence and may be a component of an important hydraulic signaling mechanism between roots and shoots.

Interactions between Senescence and Leaf Orientation Determine in Situ Patterns of Photosynthesis and Photoinhibition in Field-Grown Rice1

Photosynthesis and photoinhibition in field-grown rice (Oryza sativa L.) were examined in relation to leaf age and orientation. Two varieties (IR72 and IR65598-112-2 [BSI206]) were grown in the field in the Philippines during the dry season under highly irrigated, well-fertilized conditions. Flag leaves were examined 60 and 100 d after transplanting. Because of the upright nature of 60-d-old rice leaves, patterns of photosynthesis were determined by solar movements: light falling on the exposed surface in the morning, a low incident angle of irradiance at midday, and light striking the opposite side of the leaf blade in the afternoon. There was an early morning burst of CO2 assimilation and high levels of saturation of photosystem II electron transfer as incident irradiance reached a maximum level. However, by midday the photochemical efficiency increased again almost to maximum. Leaves that were 100 d old possessed a more horizontal orientation and were found to suffer greater levels of photoinhibition than younger leaves, and this was accompanied by increases in the de-epoxidation state of the xanthophyll cycle. Older leaves had significantly lower chlorophyll content but only slightly diminished photosynthesis capacity.

Developmental Expression and Substrate Specificities of Alfalfa Caffeic Acid 3-O-Methyltransferase and Caffeoyl Coenzyme A 3-O-Methyltransferase in Relation to Lignification1

The biosynthesis of monolignols can potentially occur via two parallel pathways involving free acids or their coenzyme A (CoA) esters. Caffeic acid 3-O-methyltransferase (COMT) and caffeoyl CoA 3-O-methyltransferase (CCOMT) catalyze functionally identical reactions in these two pathways, resulting in the formation of mono- or dimethoxylated lignin precursors. The activities of the two enzymes increase from the first to the sixth internode in stems of alfalfa (Medicago sativa L.), preceding the deposition of lignin. Alfalfa CCOMT is highly similar at the amino acid sequence level to the CCOMT from parsley, although it contains a six-amino acid insertion near the N terminus. Transcripts encoding both COMT and CCOMT are primarily localized to vascular tissue in alfalfa stems. Alfalfa CCOMT expressed in Escherichia coli catalyzes O-methylation of caffeoyl and 5-hydroxyferuloyl CoA, with preference for caffeoyl CoA. It has low activity against the free acids. COMT expressed in E. coli is active against both caffeic and 5-hydroxyferulic acids, with preference for the latter compound. Surprisingly, very little extractable O-methyltransferase activity versus 5-hydroxyferuloyl CoA is present in alfalfa stem internodes, in which relative O-methyltransferase activity against 5-hy-droxyferulic acid increases with increasing maturity, correlating with increased lignin methoxyl content.

Heat-Shock-Induced Changes in Intracellular Ca2+ Level in Tobacco Seedlings in Relation to Thermotolerance1

Exposure of plants to elevated temperatures results in a complex set of changes in gene expression that induce thermotolerance and improve cellular survival to subsequent stress. Pretreatment of young tobacco (Nicotiana plumbaginifolia) seedlings with Ca2+ or ethylene glycol-bis(β-aminoethylether)-N,N,N′,N′-tetraacetic acid enhanced or diminished subsequent thermotolerance, respectively, compared with untreated seedlings, suggesting a possible involvement of cytosolic Ca2+ in heat-shock (HS) signal transduction. Using tobacco seedlings transformed with the Ca2+-sensitive, luminescent protein aequorin, we observed that HS temperatures induced prolonged but transient increases in cytoplasmic but not chloroplastic Ca2+. A single HS initiated a refractory period in which additional HS signals failed to increase cytosolic Ca2+. However, throughout this refractory period, seedlings responded to mechanical stimulation or cold shock with cytosolic Ca2+ increases similar to untreated controls. These observations suggest that there may be specific pools of cytosolic Ca2+ mobilized by heat treatments or that the refractory period results from a temporary block in HS perception or transduction. Use of inhibitors suggests that HS mobilizes cytosolic Ca2+ from both intracellular and extracellular sources.

Neoplastic development: paradoxical relation between impaired cell growth at low population density and excessive growth at high density.

The role of heritable, population-wide cell damage in neoplastic development was studied in the 28 L subline of NIH 3T3 cells. These cells differ from the 17(3c) subline used previously for such studies in their lower frequency of "spontaneous" transformation at high population density and their greater capacity to produce large, dense transformed foci. Three cultures of the 28 L subline of NIH 3T3 cells were held under the constraint of confluence for 5 wk (5 wk 1 degree assay) and then assayed twice in succession (2 degrees and 3 degrees assays) for transformed foci and saturation density. After the 2 degrees assay, the cells were also passaged at low density to determine their exponential growth rates and cloned to determine the size and morphological features of the colonies. Concurrent measurements were made in each case with control cells that had been kept only in frequent low-density passages and cells that had been kept at confluence for only 2 wk (2 wk 1 degree). Two of the three cultures transferred from the 2 degrees assay of the 5 wk 1 degree cultures produced light transformed foci, and the third produced dense foci. The light focus-forming cultures grew to twice the control saturation density in their 2 degrees assay and 6-8 times the control density in the 3 degrees assay; saturation densities for the dense focus formers were about 10 times the control values in both assays. All three of the cultures transferred from the 2 degrees assay of the 5 wk 1 degree cultures multiplied at lower rates than controls at low densities, but the dense focus formers multiplied faster than the light focus formers. The reduced rates of multiplication of the light focus formers persisted for > 50 generations of exponential multiplication at low densities. Isolated colonies formed from single cells of the light focus formers were of a lower population density than controls; colonies formed by the dense focus formers were slightly denser than the controls but occupied only half the area. A much higher proportion of the colonies from the 5 wk 1 degree cultures than the controls consisted of giant cells or mixtures of giant and normal-appearing cells. The results reinforce the previous conclusion that the early increases in saturation density and light focus formation are associated with, and perhaps caused by, heritable, population-wide damage to cells that is essentially epigenetic in nature. The more advanced transformation characterized by large increases in saturation density and dense focus formation could have originated from rare genetic changes, such as chromosome rearrangements, known to occur at an elevated frequency in cells destabilized by antecedent cellular damage.

Architecture of a Bench-Type Carbonate Lake Margin and Its Relation to Fluvially Dominated Deltas, Las Minas Basin, Upper Miocene, Spain

The Upper Miocene stratigraphic succession of the Las Minas Basin, located at the external zone of the Betic Chain in SE Spain, preserves several examples of lake carbonate bench deposits. Excellent exposures of the carbonate benches allow detailed observation of the architecture of these sediments and provide new insights for the ‘‘steep-gradient bench margin–low energy’’ model proposed by Platt and Wright (1991). The lake carbonate benches developed in close association with fluvially dominated shallow deltas that exhibit typical Gilbert-type profiles. The delta sequences comprise bottomset prodelta marl facies, distal to proximal foreset facies, deposited mainly in a delta-front environment, and topset facies, the latter reflecting both subaqueous delta-front and subaerial delta-plain environments. The development of the carbonate benches was constrained by the convexupward morphology of the deltaic deposits, which led to the available accommodation space for the growth of the steep-gradient platforms. The benches display a progradational pattern characterized by sigmoid-oblique internal geometries and offlap upper boundary relationships, which suggests that the carbonate benches developed under slow though continuous lake-level rise. Both the dimensions of the benches and the dominant carbonate components (i.e., encrusted charophyte stems and calcified cyanobaterial remains), allow comparisons with the progradational marl benches recognized in modern temperate hardwater lakes. Accordingly, the case study presented here provides a good ancient sedimentary analog for low-energy lake carbonate benches. Moreover, the evolutionary trend inferred from the fossil example offers new insights into the depositional conditions of this type of sediment and allows recognition of the transitional pattern from bench to ramp carbonate lake margins.

Discursive constructions of social and environmental accounting in Brazil: the case of Petrobras.

In the 29 years following \"Our Common Future\" by the United Nations, there is considerable debate among governments, civil society, interest groups and business organisations about what constitutes sustainable development, which constitutes evidence for a contested discourse concerning sustainability. The purpose of this study is to understand this debate in the developing economic context of Brazil, and in particular, to understand and critique the social and environmental accounting [SEA] discursive constructions relating to the State-owned, Petrobras as well as to understand the Brazilian literature on SEA. The discourse theory [DT]-based analysis employs rhetorical redescription to analyse twenty-two reports from Petrobras from 2004-2013. I investigate the political notions by employing the methodological framework of the Logics of Critical Explanation [LCE]. LCE engenders five methodological steps: problematisation, retroduction, logics (social, political and fantasmatic), articulation and critique. The empirical discussion suggests that the hegemony of economic development operates to obfuscate, rhetorically, the development of sustainability, so as to maintain the core business of Petrobras conceived as capital accumulation. Equally, these articulations also illustrate how the constructions of SEA operate to serve the company\'s purpose with few (none) profound changes in integration of sustainability. The Brazilian literature on SEA sustains the status quo of neo-liberal market policies that operate to protect the dominant business case approach to maintain an agenda of wealth-creation in relation to social and environmental needs. The articulations of the case manifested in policies regarding, for example, corruption, which involved over-payments for contracts and unsustainable practices relating to the use of fossil fuels and demonstrated that there was antagonism between action and disclosure. The corruption scandal that emerged after SEA disclosures highlighted the rhetorical nature of disclosure when financial resources were subtracted from the company for political parties and engineering contractors hid facts through incomplete disclosures. The articulations of SEA misrepresent a broader context of the meanings associated with sustainability, which restricted the constructions of SEA to principally serve and represent the intention of the most powerful groups. The significance of SEA, then is narrowed to represent particular interests. The study argues for more critical studies as limited Brazilian literature concerning SEA kept a \'safe distance\' from substantively critiquing the constructions of SEA and its articulations in the Brazilian context. The literature review and the Petrobras\' case illustrate a variety of naming, instituting and articulatory practices that endeavour to maintain the current hegemony of development in an emerging economy, which allows Petrobras to continue to exercise significant profit at the expense of the social and environmental. The constructed idea of development in Petrobras\' discourses emphasises a rhetoric of wider development, but, in reality, these discourses were the antithesis of political, social and ethical developmental issues. These constructions aim to hide struggles between social inequalities and exploitation of natural resources and constitute excuses about a fanciful notion of rhetorical and hegemonic neo-liberal development. In summary, this thesis contributes to the prior literature in five ways: (i) the addition of DT to the analysis of SEA enhances the discussion of political elements such as hegemony, antagonism, logic of equivalence/difference, ideology and articulation; (ii) the analysis of an emerging economy such as Brazil incorporates a new perspective of the discussion of the discourses of SEA and development; (iii) this thesis includes a focus on rhetoric to discuss the maintenance of the status quo; (iv) the holistic structure of the LCE approach enlarges the understanding of the social, political and fantasmatic logics of SEA studies and; (v) this thesis combines an analysis of the literature and the case of Petrobras to characterise and critique the state of the Brazilian academy and its impacts and reflections on the significance of SEA. This thesis, therefore, argues for more critical studies in the Brazilian academy due to the persistence of idea of SEA and development that takes-for-granted deep exclusions and contradictions and provide little space for critiques.

John Warren's copy of votes from a meeting of the Boston Medical Society, 1784 May 3

This document lists the eleven votes cast at a meeting of the Boston Medical Society on May 3, 1784. It was authorized as a "true coppy" by Thomas Kast, the Secretary of the Society. The following members of the Society were present at the meeting, all of them doctors: James Pecker, James Lloyd, Joseph Gardner, Samuel Danforth, Isaac Rand, Jr., Charles Jarvis, Thomas Kast, Benjamin Curtis, Thomas Welsh, Nathaniel Walker Appleton, and doctors whose last names were Adams, Townsend, Eustis, Homans, and Whitwell. The document indicates that a meeting had been held the previous evening, as well (May 2, 1784), at which the topics on which votes were taken had been discussed. The votes, eleven in total, were all related to the doctors' concerns about John Warren and his involvement with the emerging medical school (now Harvard Medical School), that school's relation to almshouses, the medical care of the poor, and other related matters. The tone and content of these votes reveals anger on the part of the members of the Boston Medical Society towards Warren. This anger appears to have stemmed from the perceived threat of Warren to their own practices, exacerbated by a vote of the Harvard Corporation on April 19, 1784. This vote authorized Warren to apply to the Overseers of the Poor for the town of Boston, requesting that students in the newly-established Harvard medical program, where Warren was Professor of Anatomy and Surgery, be allowed to visit the hospital of the almshouse with their professors for the purpose of clinical instruction. Although Warren believed that the students would learn far more from these visits, in regards to surgical experience, than they could possibly learn in Cambridge, the proposal provoked great distrust from the members of the Boston Medical Society, who accused Warren of an "attempt to direct the public medical business from its usual channels" for his own financial and professional gain.

Iceland’s contested European Policy: The Footprint of the Past - A Small and Insular Society. Jean Monnet Occasional Paper 01/2013

Introduction. Iceland’s domestic politics and foreign affairs are undergoing drastic changes. After an economic crash, violent protests on the streets of Reykjavik for the first time in Iceland’s history contributed to the defeat of the government. The party system has been altered. A turn has been taken towards Europe after the United States left the island, first by closing its military base in 2006 and then by its clear stance not to assist the country in its economic difficulties. The former close relations with the superpower are unlikely ever to be restored. The EU membership application is placing severe constraints on political parties which are split on the issue and has put in jeopardy the unity of the first left majority in the Icelandic parliament, the Althingi. Society is in a state of flux after an unprecedented economic downscaling and the collapse of almost its entire financial sector – which had boomed rapidly beginning in the mid-1990s. The credibility of politicians, the parliament and the media is in ruins. Iceland’s smallness and its location on the geographical map – one could also say the geopolitical map – has had a profound influence on its domestic and foreign affairs. Iceland is closely associated with the other Nordic states and has adopted many of their domestic characteristics, with important exceptions. On the other hand, the country has come under American influence – geographically, it straddles the Mid-Atlantic rift – and has limited its participation in the European project. Its geographical location in the middle of the North Atlantic has led to a notion that the country’s culture is unique and should be protected by all available means. Politicians continue to play the ‘nationalistic uniqueness’ card with considerable success even though the country has been swept by globalization. Rapid modernization (which only really began in the Second World War with British and American occupations) and sudden engagement with the outside world (which only extended to the general public in the last quarter of the twentieth century) are still slowly but steadily making their mark on the country’s foreign policy. The country’s political discourse and foreign policy still bear the hallmark of the past, i.e. of a small and insular society This paper will address the political developments in Iceland since the 2008 economic crash and place it in a historical context. The aim is to understand Iceland’s present foreign policy and, in particular, the highly contested decision by its government in 2009 to apply for membership of the European Union. The paper is divided into five sections in addition to this introduction and the concluding remarks. First, it starts by explaining the importance in Iceland of a political discourse based on the concept of independence which dates back to the historical narrative of the settlement period. This section will also examine Iceland’s close relations with the other Nordic states – despite important differences between it and the others. Second, the paper will analyse the importance of the party system, i.e. the dominance of the centre-right in Icelandic politics, and the changed nature of the system. Third, it examines how Iceland further distinguishes itself from the other Nordic states in many important features. Fourthly, the paper analyses the country’s three main foreign policy priorities in the post-war period, i.e. extensions of the Exclusive Economic Zone, firm defence arrangements with the US and membership of NATO, and the drive for better market access for marine products – including a partial engagement in the European project. Fifthly, the paper examines how the country’s smallness, in terms of its central administrative capacity, has affected its domestic and foreign policy-making. The concluding section summarizes the main findings concerning the political and historical obstacles that the Social Democratic Alliance faces in its hard-fought battle to change the country’s European Policy.

Sedimentation rates calculated on surface sediment samples from different site of the Atlantic and Pacific Oceans (Table 1)

Radiocarbon ages on CaCO3 from deep-sea cores offer constraints on the nature of the CaCO3 dissolution process. The idea is that the toll taken by dissolution on grains within the core top bioturbation zone should be in proportion to their time of residence in this zone. If so, dissolution would shift the mass distribution in favor of younger grains, thereby reducing the mean radiocarbon age for the grain ensemble. We have searched in vain for evidence supporting the existence of such an age reduction. Instead, we find that for water depths of more than 4 km in the tropical Pacific the radiocarbon age increases with the extent of dissolution. We can find no satisfactory steady state explanation and are forced to conclude that this increase must be the result of chemical erosion. The idea is that during the Holocene the rate of dissolution of CaCO3 has exceeded the rain rate of CaCO3. In this circumstance, bioturbation exhumes CaCO3 from the underlying glacial sediment and mixes it with CaCO3 raining from the sea surface.

Precipitation of the sulphides of nickel & cobalt in an alkaline tartrate solution : together with an investigation into the nature of certain tartrates of these metals.

Reprinted from the Journal of the American chemical society, v. 22, no. 8, Ag. 1900.