Stable isotopic study of late Neoproterozoic-early Cambrian (?) sediments from Nagaur-Ganganagar basin, western India: possible signatures of global and regional C-isotopic events

Carbonate rocks of late Neoproterozoic-early Cambrian age occur in two extremities of the Nagaur-Ganganagar basin in western India: in east as part of Bilara hills (type locality) and in west as part of Baghewala oil field. These rocks have close stratigraphic correlation with the Ara Formation (Huqf Group, south Oman salt basin) which transgresses the late Neoproterozoic-early Cambrian boundary. Sedimentological and stable isotopic studies of these rocks show prevalence of arid and evaporitic conditions during their depostion. Close resemblance of C-isotopic profiles of Hanseran evaporites and Bilara carbonates allows intra-basinal correlation and suggests that they are coeval facies variants. There are several characteristic carbon isotopic excursions one of which can be tentatively correlated with the globally recorded excursion close to the late Neoproterozoic-early Cambrian boundary. In contrast other peaks are possibly of regional significance and can be attributed to fluctuations in bioproductivity, correlatable with variation in nutrient supply on a basinal scale. Highly depleted carbon isotopic composition of the organic matter in subsurface organic-rich carbonates (Upper carbonate Formation, Baghewala-II core) has been ascribed to incorporation of biomass synthesized by chemoautotrophic bacteria under anoxic or eutrophic basinal condition caused by salinity stratification

Flow control of real-time unicast multimedia applications in best-effort networks

One of the fastest growing segments of Internet applications are real-time mul- timedia applications, like Voice over Internet Protocol (VoIP). Real-time multimedia applications use the User Datagram Protocol (UDP) as the transport protocol because of the inherent conservative nature of the congestion avoidance schemes of Transmis- sion Control Protocol (TCP). The e®ects of uncontrolled °ows on the Internet have not yet been felt because UDP tra±c frequently constitutes only » 20% of the total Internet tra±c. It is pertinent that real-time multimedia applications become better citizens of the Internet, while at the same time deliver acceptable Quality of Service (QoS). Traditionally, packet losses and the increase in the end-to-end delay experienced by some of the packets characterizes congestion in the network. These two signals have been used to develop most known °ow control schemes. The current research considers the °ow accumulation in the network as the signal for use in °ow control. The most signi¯cant contribution of the current research is to propose novel end- to-end °ow control schemes for unicast real-time multimedia °ows transmitting over best-e®ort networks. These control schemes are based on predictive control of the accumulation signal. The end-to-end control schemes available in the literature are based on reactive control that do not take into account the feedback delay existing between the sender and the receiver nor the forward delay in the °ow dynamics. The performance of the proposed control schemes has been evaluated using the ns-2 simulation environment. The research concludes that active control of hard real- time °ows delivers the same or somewhat better QoS as High Bit Rate (HBR, no control), but with a lower average bit rate. Consequently, it helps reduce bandwidth use of controlled real-time °ows by anywhere between 31:43% to 43:96%. Proposed reactive control schemes deliver good QoS. However, they do not scale up as well as the predictive control schemes. Proposed predictive control schemes are e®ective in delivering good quality QoS while using up less bandwidth than even the reactive con- trol schemes. They scale up well as more real-time multimedia °ows start employing them

Prediction of MPEG-coded video source traffic using neural networks

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 202-207).Issued also on microfiche from Lange Micrographics.One of the most popular standards used for storing, delivering and viewing real-time streaming media over the Internet is MPEG. The time-series representing frame/VOP sizes of an MPEG sequence is extremely noisy and has very long-range time dependency. Present research aims to provide a generalized solution to the problem of predicting the frames/VOP sizes of MPEG-coded real-time video streams for single and multiple steps ahead. In order to incorporate the nonlinear behavior of time-series representing frame or VOP sizes of MPEG-encoded streams in mathematical models, Artificial Neural Networks (ANNs) are used extensively in this research. The final model for single-step-ahead prediction consists of one RMLP network for prediction of I-VOPs and two FMLP networks for prediction of P- and B-VOPs, respectively. Each of these networks has external indicators derived from the time-series. Multi-step-ahead prediction of individual frame/VOP sizes is found to be very inaccurate. A moving average of the sizes of frames/VOPs is generated from the individual frame sizes. A multi-step-ahead prediction scheme based on RMLP networks is developed and used to perform two-step-ahead and four-step-ahead prediction of moving average of the frame/VOP sizes with some success. This research demonstrates that video source traffic encoded using MPEG standards can be predicted single-step-ahead with reasonable amount of accuracy using neural networks as predictors. Use of two-step-ahead and four-step-ahead prediction schemes to predict the time series of the moving average of size of frame/VOPs is a novel concept introduced in this research. This predictive capability should be useful in the more effective bandwidth allocation mechanism and in the development of a control scheme to control the multimedia traffic over wide area networks

Tutoring in K--12: Parent Satisfaction and Interpersonal Process

Tutoring has long been thought of as an ideal educational strategy because of the individual attention and relational context that it allows. However, due to the cost of personalizing education, the availability of tutoring has been limited. Recently under the No Child Left Behind Act, failing schools have been required to offer contracted tutoring in the form of supplemental educational services (SES). This archival study made use of parent satisfaction survey data that had already been collected by a private nonprofit educational agency providing such services. This data was unique because it had corresponding scores for both tutor and tutee allowing for dyadic analysis. Findings from the parent survey indicate that parents were highly satisfied with the tutoring services and indicate that higher satisfaction with convenience variables, preference of home based services, or having a child with a disability predicted higher rates of reenrollment. Dyadic analysis and variance partitioning using the SRM one with many design found that tutors are distinguishable from each other in terms of perceived student improvement. Tutors and parents have moderate agreement on how students are improving relative to other students. Finally, the unique relationship between tutor and tutee contain quite a bit of the variance in perception of improvement, supporting the idea that interpersonal process is an important variable in tutoring.

High Proton Mobility, Solvent Induced Single Crystal to Single Crystal Structural Transformation, and Related Studies on a Family of Compounds Formed from Mn₃ Oxo-Clusters

The reaction between 4,4′-sulfonyldibenzoic acid (H₂SDBA) and manganese under mild conditions resulted in the isolation of two new three-dimensional compounds, [Mn₄(C₁₄H₈O₆S)₄­(DMA)₂]­·3DMA,<b> I</b>, and [Mn₃(C₁₄H₈O₆S)₃­(DMA)₂­(MeOH)]­·DMA, <b>IIa</b>. Both structures have Mn₃ trimer oxo cluster units. While the Mn₃ oxoclusters are connected through octahedral manganese forming one-dimensional Mn–O–Mn chains in <b>I</b>, the Mn₃ units are isolated in <b>IIa</b>. The SDBA units connect the Mn–O–Mn chains and the Mn₃ clusters giving rise to the three-dimensional structure. Both compounds have coordinated and free solvent molecules. In <b>IIa</b>, two different solvent molecules are coordinated, of which one solvent can be reversibly exchanged by a variety of other similar solvents via a solvent-mediated single crystal to single crystal (SCSC) transformation. The free lattice DMA solvent molecules in <b>I</b> can be exchanged by water molecules resulting in hydrophilic channels. Proton conductivity studies on <b>I</b> reveals a high proton mobility with conductivity values of ∼0.87 × 10^–3 Ω^–1 cm^–1 at 34 °C and 98% RH, which is comparable to some of the good proton conductivity values observed in inorganic coordination polymers. We have also shown structural transformation of <b>I</b> to <b>IIa</b> through a possible dissolution and recrystallization pathway. In addition, both <b>I</b> and <b>IIa</b> appear to transform to two other manganese compounds [H₃O]­[Mn₃(μ₃-OH)­(C₁₄H₈O₆S)₃­(H₂O)]­(DMF)₅ and [H₃O]₂­[Mn₇(μ₃-OH)₄­(C₁₄H₈O₆S)₆­(H₂O)₄]­(H₂O)₂­(DMF)₈ under suitable reaction conditions. We have partially substituted Co in place of Mn in the Mn₃ trimer clusters forming [CoMn₂­(C₁₄H₈O₆S)₃­(DMA)₂­(EtOH)]­·DMA, <b>III</b>, a structure that is closely related to <b>IIa</b>. All the compounds reveal antiferromagnetic behavior. On heating, the cobalt substituted phase (compound <b>III</b>) forms a CoMn₂O₄ spinel phase with particle sizes in the nanometer range

Organization of Mn-clusters in pcu and bcu networks: synthesis, structure, and properties

Two new anionic inorganic–organic hybrid compounds [H3O][Mn3(&#956;3-OH)(C14H8O6S)3(H2O)](DMF)5, I, and [H3O]2[Mn7(&#956;3-OH)4(C14H8O6S)6(H2O)4](H2O)2(DMF)8, II, have been prepared by employing mild solvothermal methods. Both the compounds have three-dimensionally extended structures formed by Mn6 and Mn7 clusters, respectively. The connectivity between Mn6 and Mn7 clusters and 4,4'-sulfonyldibenzoic acid anions (SDBA2–) results in a six connected pcu network in I and an eight connected bcu network in II. The presence of hydronium ion (H3O+) along with the solvent molecules in the channels of both the compounds suggested proton conduction in the solids. Proton conductivity studies gave values of &#8764;3 &#215; 10-4 &#937;-1 cm-1 98% relative humidity in both the compounds. The high activation energies indicate a vehicle mechanism in the compounds I and II. Magnetic studies indicate antiferromagnetic behavior in both the compounds

Demethylation of Non-CpG Sites in DNA Is Initiated by TET2 5-Methylcytosine Dioxygenase

In the mammalian genome, cytosine methylation predominantly occurs at CpG sites. In addition, a number of recent studies have uncovered extensive C5 cytosine methylation (5mC) at non-CpG (5mCpH, where H = A/C/T) sites. Little is known about the enzyme responsible for active demethylation of 5mCpH sites. Using a very sensitive and quantitative LC–MS/MS method, we demonstrate that the human TET2, an iron (II)- and 2OG-dependent dioxygenase, which is a frequently mutated gene in several myeloid malignancies, as well as in a number of other types of cancers, can oxidize 5mCpH sites in double-stranded DNA in vitro. Similar to oxidation of 5mCpG, oxidation of 5mC at CpH sites produces 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxycytosine (5caC) bases in DNA. After 5mCpG, which is the most preferred substrate, TET2 prefers 5mCpC as a substrate, followed by 5mCpA and then 5mCpT. Since the TDG/BER pathway and deformylation or decarboxylation of 5fC or 5caC, respectively, can convert 5fCpH and 5caCpH to an unmodified cytosine base in DNA, our results suggest a novel demethylation pathway of 5mCpH sites initiated by TET2 dioxygenase

Organization of Mn-Clusters in <i>pcu</i> and <i>bcu</i> Networks: Synthesis, Structure, and Properties

Two new anionic inorganic–organic hybrid compounds [H₃O]­[Mn₃(μ₃-OH)­(C₁₄H₈O₆S)₃(H₂O)]­(DMF)₅, <b>I</b>, and [H₃O]₂[Mn₇(μ₃-OH)₄(C₁₄H₈O₆S)₆(H₂O)₄]­(H₂O)₂(DMF)₈, <b>II</b>, have been prepared by employing mild solvothermal methods. Both the compounds have three-dimensionally extended structures formed by Mn₆ and Mn₇ clusters, respectively. The connectivity between Mn₆ and Mn₇ clusters and 4,4′-sulfonyldibenzoic acid anions (SDBA^2–) results in a six connected <i>pcu</i> network in <b>I</b> and an eight connected <i>bcu</i> network in <b>II</b>. The presence of hydronium ion (H₃O⁺) along with the solvent molecules in the channels of both the compounds suggested proton conduction in the solids. Proton conductivity studies gave values of ∼3 × 10^–4 Ω^–1 cm^–1 98% relative humidity in both the compounds. The high activation energies indicate a vehicle mechanism in the compounds <b>I</b> and <b>II</b>. Magnetic studies indicate antiferromagnetic behavior in both the compounds

Organization of Mn-Clusters in <i>pcu</i> and <i>bcu</i> Networks: Synthesis, Structure, and Properties

Two new anionic inorganic–organic hybrid compounds [H₃O]­[Mn₃(μ₃-OH)­(C₁₄H₈O₆S)₃(H₂O)]­(DMF)₅, <b>I</b>, and [H₃O]₂[Mn₇(μ₃-OH)₄(C₁₄H₈O₆S)₆(H₂O)₄]­(H₂O)₂(DMF)₈, <b>II</b>, have been prepared by employing mild solvothermal methods. Both the compounds have three-dimensionally extended structures formed by Mn₆ and Mn₇ clusters, respectively. The connectivity between Mn₆ and Mn₇ clusters and 4,4′-sulfonyldibenzoic acid anions (SDBA^2–) results in a six connected <i>pcu</i> network in <b>I</b> and an eight connected <i>bcu</i> network in <b>II</b>. The presence of hydronium ion (H₃O⁺) along with the solvent molecules in the channels of both the compounds suggested proton conduction in the solids. Proton conductivity studies gave values of ∼3 × 10^–4 Ω^–1 cm^–1 98% relative humidity in both the compounds. The high activation energies indicate a vehicle mechanism in the compounds <b>I</b> and <b>II</b>. Magnetic studies indicate antiferromagnetic behavior in both the compounds