Stable isotopic and carbonate cyclicity in deep sea sediments from different DSDP Holes

Oxygen and carbon isotopic variability of the dominant (<38 µm) carbonate fraction within bedded, organic-carbon rich Lower Cretaceous sediment intervals from various DSDP sites are closely correlated with preservational changes in the carbonates. Isotopic fluctuations are absent where carbonate contents vary little and where the carbonate fraction is dominated by biogenic phytoplankton remains. Within each of the studied intervals oxygen and carbon isotopic ratios become increasingly more negative in samples with carbonate contents higher than about 60% in which the proportion of diagenetic microcarbonate increases rapidly. Carbon isotopic ratios show a trend towards positive values in samples with carbonate contents of less than 40% and strong signs of dissolution. The taxonomic composition of nannofossil assemblages varies little within single intervals, despite significant differential diagenesis among individual beds; this points towards ecological stability of oceanic surface waters during the deposition of alternating beds. Bedding is, however, closely related to changing bioturbation intensity, indicating repeated fluctuations of the deep-water renewal rates and oxygen supply. Various microbial decomposition processes of organic matter leading to bed-specific differential carbonate diagenesis resulted in an amplification of primary bedding features and are considered responsible for most of the observed fluctuations in the stable isotopic ratios and carbonate contents.

Characterization cement pastes degraded in lanoratory solutions and physiochemical parameters employed for modeling the process

Previously degradation studies carried out, over a number of different mortars by the research team, have shown that observed degradation does not exclusively depend on the solution equilibrium pH, nor the aggressive anions relative solubility. In our tests no reason was found that could allow us to explain, why same solubility anions with a lower pH are less aggressive than others. The aim of this paper is to study cement pastes behavior in aggressive environments. As observed in previous research, this cement pastes behaviors are not easily explained only taking into account only usual parameters, pH, solubility etc. Consequently the paper is about studying if solution physicochemical characteristics are more important in certain environments than specific pH values. The paper tries to obtain a degradation model, which starting from solution physicochemical parameters allows us to interpret the different behaviors shown by different composition cements. To that end, the rates of degradation of the solid phases were computed for each considered environment. Three cement have been studied: CEM I 42.5R/SR, CEM II/A-V 42.5R and CEM IV/B-(P-V) 32.5 N. The pastes have been exposed to five environments: sodium acetate/acetic acid 0.35 M, sodium sulfate solution 0.17 M, a solution representing natural water, saturated calcium hydroxide solution and laboratory environment. The attack mechanism was meant to be unidirectional, in order to achieve so; all sides of cylinders were sealed except from the attacked surface. The cylinders were taking out of the exposition environments after 2, 4, 7, 14, 30, 58 and 90 days. Both aggressive solution variations in solid phases and in different depths have been characterized. To each age and depth the calcium, magnesium and iron contents have been analyzed. Hydrated phases evolution studied, using thermal analysis, and crystalline compound changes, using X ray diffraction have been also analyzed. Sodium sulphate and water solutions stabilize an outer pH near to 8 in short time, however the stability of the most pH dependent phases is not the same. Although having similar pH and existing the possibility of forming a plaster layer near to the calcium leaching surface, this stability is greater than other sulphate solutions. Stability variations of solids formed by inverse diffusion, determine the rate of degradation.

Classical solutions for a logarithmic fractional diffusion equation

We prove global existence and uniqueness of strong solutions to the logarithmic porous medium type equation with fractional diffusion ?tu + (?)1/2 log(1 + u) = 0, posed for x ? R, with nonnegative initial data in some function space of LlogL type. The solutions are shown to become bounded and C? smooth in (x, t) for all positive times. We also reformulate this equation as a transport equation with nonlocal velocity and critical viscosity, a topic of current relevance. Interesting functional inequalities are involved.

Variation in per capita interaction strength: Thresholds due to nonlinear dynamics and nonequilibrium conditions

I measured the strength of interaction between a marine herbivore and its growing resource over a realistic range of absolute and relative abundances. The herbivores (hermit crabs: Pagurus spp.) have slow and/or weak functional and numerical responses to epiphytic diatoms (Isthmia nervosa), which show logistic growth in the absence of consumers. By isolating this interaction in containers in the field, I mimicked many of the physical and biological variables characteristic of the intertidal while controlling the densities of focal species. The per capita effects of consumers on the population dynamics of their resource (i.e., interaction strength) were defined by using the relationship between hermit crab density and proportional change in the resource. When this relationship is fit by a Weibull function, a single parameter distinguishes constant interaction strength from one that varies as a function of density. Constant interaction strength causes the proportion of diatoms to fall linearly or proportionally as hermit crab density increases whereas per capita effects that increase with density cause an accelerating decline. Although many mathematical models of species interactions assume linear dynamics and invariant parameters, at least near equilibrium, the per capita effects of hermit crabs on diatoms varied substantially, apparently crossing a threshold from weak to strong when consumption exceeded resource production. This threshold separates a domain of coexistence from one of local extinction of the resource. Such thresholds may help explain trophic cascades, resource compensation, and context-dependent interaction strengths, while indicating a way to predict trophic effects, despite nonlinearities, as a function of vital rates.

Plo1 Kinase Recruitment to the Spindle Pole Body and Its Role in Cell Division in Schizosaccharomyces pombe

Polo kinases execute multiple roles during cell division. The fission yeast polo related kinase Plo1 is required to assemble the mitotic spindle, the prophase actin ring that predicts the site for cytokinesis and for septation after the completion of mitosis (Ohkura et al., 1995; Bahler et al., 1998). We show that Plo1 associates with the mitotic but not interphase spindle pole body (SPB). SPB association of Plo1 is the earliest fission yeast mitotic event recorded to date. SPB association is strong from mitotic commitment to early anaphase B, after which the Plo1 signal becomes very weak and finally disappears upon spindle breakdown. SPB association of Plo1 requires mitosis-promoting factor (MPF) activity, whereas its disassociation requires the activity of the anaphase-promoting complex. The stf1.1 mutation bypasses the usual requirement for the MPF activator Cdc25 (Hudson et al., 1990). Significantly, Plo1 associates inappropriately with the interphase SPB of stf1.1 cells. These data are consistent with the emerging theme from many systems that polo kinases participate in the regulation of MPF to determine the timing of commitment to mitosis and may indicate that pole association is a key aspect of Plo1 function. Plo1 does not associate with the SPB when septation is inappropriately driven by deregulation of the Spg1 pathway and remains SPB associated if septation occurs in the presence of a spindle. Thus, neither Plo1 recruitment to nor its departure from the SPB are required for septation; however, overexpression of plo1+ activates the Spg1 pathway and causes transient Cdc7 recruitment to the SPB and multiple rounds of septation.

A Gene Encoding Proline Dehydrogenase Is Not Only Induced by Proline and Hypoosmolarity, but Is Also Developmentally Regulated in the Reproductive Organs of Arabidopsis1

The cDNA clone ERD5 (early responsive to dehydration), isolated from 1-h-dehydrated Arabidopsis, encodes a precursor of proline (Pro) dehydrogenase (ProDH), which is a mitochondrial enzyme involved in the first step of the conversion of Pro to glutamic acid. The transcript of the erd5 (ProDH) gene was undetectable when plants were dehydrated, but large amounts of transcript accumulated when plants were subsequently rehydrated. Accumulation of the transcript was also observed in plants that had been incubated under hypoosmotic conditions in media that contained l- or d-Pro. We isolated a 1.4-kb DNA fragment of the putative promoter region of the ProDH gene. The β-glucuronidase (GUS) reporter gene driven by the 1.4-kb ProDH promoter was induced not only by rehydration but also by hypoosmolarity and l- and d-Pro at significant levels in transgenic Arabidopsis plants. The promoter of the ProDH gene directs strong GUS activity in reproductive organs such as pollen and pistils and in the seeds of the transgenic plants. GUS activity was detected in vegetative tissues such as veins of leaves and root tips when the transgenic plants were exposed to hypoosmolarity and Pro solutions. GUS activity increased during germination of the transgenic plants under hypoosmolarity. The relationship between Pro metabolism and the physiological aspects of stress response and development are discussed.

Caught in the act: gas and stellar velocity dispersions in a fast Quenching compact star-forming galaxy at z ~ 1.7

We present Keck I MOSFIRE spectroscopy in the Y and H bands of GDN-8231, a massive, compact, star-forming galaxy at a redshift of z ~ 1.7. Its spectrum reveals both Hα and [Nii] emission lines and strong Balmer absorption lines. The Hα and Spitzer MIPS 24 μm fluxes are both weak, thus indicating a low star-formation rate of SFR≲5-10 M_⨀ yr−1. This, added to a relatively young age of ~700 Myr measured from the absorption lines, provides the first direct evidence for a distant galaxy being caught in the act of rapidly shutting down its star formation. Such quenching allows GDN-8231 to become a compact, quiescent galaxy, similar to three other galaxies in our sample, by z ~ 1.5. Moreover, the color profile of GDN-8231 shows a bluer center, consistent with the predictions of recent simulations for an early phase of inside-out quenching. Its line-of-sight velocity dispersion for the gas, σ_LOG^gas = 127 ± 32 km s^−1, is nearly 40% smaller than that of its stars, σ_LOG^* = 215 ± 35 km s^−1. High-resolution hydro-simulations of galaxies explain such apparently colder gas kinematics of up to a factor of ~1.5 with rotating disks being viewed at different inclinations and/or centrally concentrated star-forming regions. A clear prediction is that their compact, quiescent descendants preserve some remnant rotation from their star-forming progenitors.

Orientation of the genetic variance-covariance matrix and the fitness surface for multiple male sexually selected traits

Stabilizing selection has been predicted to change genetic variances and covariances so that the orientation of the genetic variance-covariance matrix (G) becomes aligned with the orientation of the fitness surface, but it is less clear how directional selection may change G. Here we develop statistical approaches to the comparison of G with vectors of linear and nonlinear selection. We apply these approaches to a set of male sexually selected cuticular hydrocarbons (CHCs) of Drosophila serrata. Even though male CHCs displayed substantial additive genetic variance, more than 99% of the genetic variance was orientated 74.9degrees away from the vector of linear sexual selection, suggesting that open-ended female preferences may greatly reduce genetic variation in male display traits. Although the orientation of G and the fitness surface were found to differ significantly, the similarity present in eigenstructure was a consequence of traits under weak linear selection and strong nonlinear ( convex) selection. Associating the eigenstructure of G with vectors of linear and nonlinear selection may provide a way of determining what long-term changes in G may be generated by the processes of natural and sexual selection.

Milling quality and protein properties of autumn-sown Chinese wheats evaluated through multi-location trials

Eight milling quality and protein properties of autumn-sown Chinese wheats were investigated using 59 cultivars and advanced lines grown in 14 locations in China from 1995 to 1998. Wide ranges of variability for all traits were observed across genotypes and locations. Genotype, location, year, and their interactions all significantly influenced most of the quality parameters. Kernel hardness, Zeleny sedimentation value, and mixograph development time were predominantly influenced by the effects of genotype. Genotype, location and genotype x location interaction were all important sources of variation for thousand kernel weight, test weight, protein content, and falling number, whereas genotype x location interaction had the largest effect on flour yield. Most of the genotypes were characterized by weak gluten strength with Zeleny sedimentation values less than 40 ml and mixograph development time shorter than 3 min. Eight groups of genotypes were recognized based on the average quality performance, grain hardness and gluten strength were the two parameters that determined the grouping, with contributions from protein content. Genotypes such as Zhongyou 16 and Annong 8903 displayed good milling quality, high grain hardness, protein content and strong gluten strength with high sedimentation value and long mixograph development time. Genotypes such as Lumai 15 and Yumai 18 were characterized by low grain hardness, protein content and weak gluten strength. Genotypes such as Yannong 15 and Chuanmai 24 were characterized by strong gluten strength with high sedimentation value and long mixograph development time, but low grain hardness and protein content lower than 12.3%. Genotypes such as Jingdong 6 and Xi'an 8 had weak gluten strength, but with high grain hardness and protein content higher than 12.2%. Five groups of locations were identified, and protein content and gluten strength were the two parameters that determined the grouping. Beijing, Shijiazhuang, Nanyang, Zhumadian and Nanjing produced wheats with medium to strong gluten strength and medium protein content, although there was still a large variation for most of the traits investigated between the locations. Wheat produced in Yantai was characterized by strong gluten strength, but with low protein content. Jinan, Anyang and Linfen locations produced wheats with medium to weak gluten strength and medium to high protein content. Wheats produced in Yangling, Zhenzhou, and Chengdu were characterized by weak gluten strength with medium to low protein content, whereas wheats produced in Xuzhou and Wuhan were characterized by weak gluten strength with low protein content. Industrial grain quality could be substantially improved through integrating knowledge of geographic genotype distribution with key location variables that affected end-use quality.

Quantum computation using weak nonlinearities: Robustness against decoherence

We investigate decoherence effects in the recently suggested quantum-computation scheme using weak nonlinearities, strong probe coherent fields, detection, and feedforward methods. It is shown that in the weak-nonlinearity-based quantum gates, decoherence in nonlinear media can be made arbitrarily small simply by using arbitrarily strong probe fields, if photon-number-resolving detection is used. On the contrary, we find that homodyne detection with feedforward is not appropriate for this scheme because in this case decoherence rapidly increases as the probe field gets larger.

Strong spectral filtering for a mode-locked similariton fiber laser

We propose a novel mode-locked fiber laser design that relies on attracting similariton solutions in fiber amplifiers with normal group-velocity dispersion and strong spectral filtering to compensate increased pulse duration and bandwidth. Stable high-energy, large-bandwidth pulses are obtained that can be linearly compressed, resulting in ultrashort pulses.

State–society relations in a dynamic framework:the case of the Far East and Sub-Saharan Africa

According to the textbook approach, the developmental states of the Far East have been considered as strong and autonomous entities. Although their bureaucratic elites have remained isolated from direct pressures stemming from society, the state capacity has also been utilised in order to allocate resources in the interest of the whole society. Yet, society – by and large –has remained weak and subordinated to the state elite. On the other hand, the general perception of Sub-Saharan Africa (SSA) has been just the opposite. The violent and permanent conflict amongst rent-seeking groups for influence and authority over resources has culminated in a situation where states have become extremely weak and fragmented, while society – depending on the capacity of competing groups for mobilising resources to organise themselves mostly on a regional or local level (resulting in local petty kingdoms) – has never had the chance to evolve as a strong player. State failure in the literature, therefore, – in the context of SSA – refers not just to a weak and captured state but also to a non-functioning, and sometimes even non-existent society, too. Recently, however, the driving forces of globalisation might have triggered serious changes in the above described status quo. Accordingly, our hypothesis is the following: globalisation, especially the dynamic changes of technology, capital and communication have made the simplistic “strong state–weak society” (in Asia) and “weak state–weak society” (in Africa) categorisation somewhat obsolete. While our comparative study has a strong emphasis on the empirical scrutiny of trying to uncover the dynamics of changes in state–society relations in the two chosen regions both qualitatively and quantitatively, it also aims at complementing the meaning and essence of the concepts and methodology of stateness, state capacity and state-society relations, the well-known building blocks of the seminal works of Evans (1995), Leftwich (1995), Migdal (1988) or Myrdal (1968).

State–society relations in a dynamic framework: The case of the Far East and Sub-Saharan Africa.

According to the textbook approach, the developmental states of the Far East have been considered as strong and autonomous entities. Although their bureaucratic elites have remained isolated from direct pressures stemming from society, the state capacity has also been utilised in order to allocate resources in the interest of the whole society. Yet, society – by and large –has remained weak and subordinated to the state elite. On the other hand, the general perception of Sub-Saharan Africa (SSA) has been just the opposite. The violent and permanent conflict amongst rent-seeking groups for influence and authority over resources has culminated in a situation where states have become extremely weak and fragmented, while society – depending on the capacity of competing groups for mobilising resources to organise themselves mostly on a regional or local level (resulting in local petty kingdoms) – has never had the chance to evolve as a strong player. State failure in the literature, therefore, – in the context of SSA – refers not just to a weak and captured state but also to a non-functioning, and sometimes even non-existent society, too. Recently, however, the driving forces of globalisation might have triggered serious changes in the above described status quo. Accordingly, our hypothesis is the following: globalisation, especially the dynamic changes of technology, capital and communication have made the simplistic “strong state–weak society” (in Asia) and “weak state–weak society” (in Africa) categorisation somewhat obsolete. While our comparative study has a strong emphasis on the empirical scrutiny of trying to uncover the dynamics of changes in state–society relations in the two chosen regions both qualitatively and quantitatively, it also aims at complementing the meaning and essence of the concepts and methodology of stateness, state capacity and state-society relations, the well-known building blocks of the seminal works of Evans (1995), Leftwich (1995), Migdal (1988) or Myrdal (1968).

Latin America and the Caribbean in 2011 and Beyond: A conversation among Latin America and Caribbean Specialists.

For the first time in more than fifty years, the domestic and external conflicts in Latin America and the Caribbean (LAC) are not primarily ideological in nature. Democracy continues to thrive and its promise still inspires hope. In contrast, the illegal production, consumption, and trading of drugs – and its links to criminal gangs and organizations – represent major challenges to the region, undermining several States’ already weak capacity to govern. While LAC macroeconomic stability has remained resilient, illegal economies fill the region, often offering what some States have not historically been able to provide – elements of human security, opportunities for social mobility, and basic survival. Areas controlled by drug trafficking organizations (DTOs) are now found in Central America, Mexico, and the favelas of Rio de Janeiro and São Paulo, reflecting their competition for land routes and production areas. Cartels such as La Familia, Los Zetas, and Primeiro Comando da Capital (PCC-Brazil), among others, operate like trade and financial enterprises that manage millions of dollars and resources, demonstrating significant business skills in adapting to changing circumstances. They are also merciless in their application of violence to preserve their lucrative enterprises. The El Salvador-Guatemala-Honduras triangle in Central America is now the most violent region in the world, surpassing regions in Africa that have been torn by civil strife for years. In Brazil’s favelas and Guatemala’s Petén region, the military is leaving the barracks again; not to rule, however, but to supplement and even replace the law enforcement capacity of weak and discredited police forces. This will challenge the military to apply lessons learned during the course of their experience in government, or from the civil wars that plagued the region for nearly 50 years during the Cold War. Will they be able to conduct themselves according to the professional ethics that have been inculcated over the past 20 years without incurring violations of human rights? Belief in their potential to do good is high according to many polls as the Armed Forces still enjoy a favorable perception in most societies, despite frequent involvement in corruption. Calling them to fight DTOs, however, may bring them too close to the illegal activities they are being asked to resist, or even rekindle the view that only a “strong hand” can resolve national troubles. The challenge of governance is occurring as contrasts within the region are becoming sharper. There is an increasing gap between nations positioned to surpass their “developing nation” status and those that are practically imploding as the judicial, political and enforcement institutions fall further into the quagmire of illicit activities. Several South American nations are advancing their political and economic development. Brazil in particular has realized macro-economic stability, made impressive gains in poverty reduction, and is on track to potentially become a significant oil producer. It is also an increasingly influential power, much closer to the heralded “emerging power” category that it aspired to for most of the 20th century. In contrast, several Central American States have become so structurally deficient, and have garnered such limited legitimacy, that their countries have devolved into patches of State controlled and non-State-controlled territory, becoming increasingly vulnerable to DTO entrenchment. In the Caribbean, the drug and human trafficking business also thrives. Small and larger countries are experiencing the growing impact of illicit economies and accompanying crime and violence. Among these, Guyana and Suriname face greater uncertainty, as they juggle both their internal affairs and their relations with Brazil and Venezuela. Cuba also faces new challenges as it continues focusing on internal rather than external affairs and attempts to ensure a stable leadership succession while simultaneously trying to reform its economy. Loosening the regime’s tight grip on the economy while continuing to curtail citizen’s civil rights will test the leadership’s ability to manage change and prevent a potential socio-economic crisis from turning into an existential threat. Cuba’s past ideological zest is now in the hands of Venezuela’s President Hugo Chavez, who continues his attempts to bring the region together under Venezuelan leadership ideologically based on a “Bolivarian” anti-U.S. banner, without much success. The environment and natural disasters will merit more attention in the coming years. Natural events will produce increasing scales of destruction as the States in the region fail to maintain and expand existing infrastructure to withstand such calamities and respond to their effects. Prospects for earthquakes, tsunamis, and hurricanes are high, particularly in the Caribbean. In addition, there are growing rates of deforestation in nearly every country, along with a potential increase in cross-sector competition for resources. The losers might be small farmers, due to their inability to produce quantities commensurate to larger conglomerates. Regulations that could mitigate these types of situations are lacking or openly violated with near impunity. Indigenous and other vulnerable populations, including African descendants, in several Andean countries, are particularly affected by the increasing extraction of natural resources taking place amongst their terrain. This has led to protests against extraction activities that negatively affect their livelihoods, and in the process, these historically underprivileged groups have transitioned from agenda-based organization to one that is bringing its claims and grievances to the national political agenda, becoming more politically engaged. Symptomatic of these social issues is the region’s chronically poor quality of education that has consistently failed to reduce inequality and prepare new generations for jobs in the competitive global economy, particularly the more vulnerable populations. Simultaneously, the educational deficit is also exacerbated by the erosion of access to information and freedom of the press. The international panorama is also in flux. New security entities are challenging the old establishment. The Union of South American Nations, The South American Defense Council, the socialist Bolivarian Alliance, and other entities seem to be defying the Organization of American States and its own defense mechanisms, and excluding the U.S. And the U.S.’s attention to areas in conflict, namely Iraq, Afghanistan, and Pakistan – rather than to the more stable Latin America and Caribbean – has left ample room for other actors to elbow in. China is now the top trading partner for Brazil. Russian and Iran are also finding new partnerships in the region, yet their links appear more politically inclined than those of China. Finally, the aforementioned increasing commercial ties by LAC States with China have accelerated a return to the preponderance of commodities as sources of income for their economies. The increased extraction of raw material for export will produce greater concern over the environmental impact that is created by the exploitation of natural resources. These expanded trade opportunities may prove counterproductive economically for countries in the region, particularly for Brazil and Chile, two countries whose economic policies have long sought diversification from dependence on commodities to the development of service and technology based industries.