Mark Young | Montana State University - Bozeman (original) (raw)

Papers by Mark Young

The ISME journal, Jan 30, 2015

Understanding of viral assemblage structure in natural environments remains a daunting task. Tota... more Understanding of viral assemblage structure in natural environments remains a daunting task. Total viral assemblage sequencing (for example, viral metagenomics) provides a tractable approach. However, even with the availability of next-generation sequencing technology it is usually only possible to obtain a fragmented view of viral assemblages in natural ecosystems. In this study, we applied a network-based approach in combination with viral metagenomics to investigate viral assemblage structure in the high temperature, acidic hot springs of Yellowstone National Park, USA. Our results show that this approach can identify distinct viral groups and provide insights into the viral assemblage structure. We identified 110 viral groups in the hot springs environment, with each viral group likely representing a viral family at the sub-family taxonomic level. Most of these viral groups are previously unknown DNA viruses likely infecting archaeal hosts. Overall, this study demonstrates the u...

Environmental Toxicology & Water Quality, 1989

Journal of Physical Chemistry A, 2009

Presented at the 2001 NCPV Program Review Meeting: Comparison of use of TMB, TEB, and BF3 to dibo... more Presented at the 2001 NCPV Program Review Meeting: Comparison of use of TMB, TEB, and BF3 to diborane for MOCVD growth of BGaInAs. BGaInAs can potentially be used in strain-free high-efficiency III-V solar cells, but the growth of sufficiently high-quality epitaxial BGaInAs using diborane has proven difficult. We compare the use of alternative boron precursors (trimethylboron [TMB], triethylboron [TEB], and

Presented at the 2001 NCPV Program Review Meeting: Hydrazine, NFâ, dimethylhydrazine, trimethylga... more Presented at the 2001 NCPV Program Review Meeting: Hydrazine, NFâ, dimethylhydrazine, trimethylgallium, and triethylgallium are studied for the growth of GaAs{sub 1-x}Nâ by metal-organic chemical-vapor deposition (MOCVD). NFâ is shown to incorporate nitrogen very much like hydrazine, both of which are more efficient nitrogen sources than di-methylhydrazine. The choice of gallium precursor (triethyl-gallium or trimethylgallium) also affects the nitrogen incorporation.

III-V semiconductors grown on silicon substrates are very attractive for lower-cost, high-efficie... more III-V semiconductors grown on silicon substrates are very attractive for lower-cost, high-efficiency multijunction solar cells, but lattice-mismatched alloys that result in high dislocation densities have been unable to achieve satisfactory performance. GaNxP1-x-yAsy is a direct-gap III-V alloy that can be grown lattice-matched to Si when y= 4.7x - 0.1. We have proposed the use of lattice-matched GaNPAs on silicon for

Dilute nitride alloys provide a powerful tool for engineering the band gap and lattice constant o... more Dilute nitride alloys provide a powerful tool for engineering the band gap and lattice constant of III-V alloys. However, nitrogen degrades the performance of GaAs solar cells. This project seeks to understand and demonstrate the limits of performance of GaInNAs alloys by (a) correlating deep-level transient spectroscopy (DLTS) data with device performance and (b) using molecular beam epitaxy (MBE) to

A four-junction GaInP/GaAs/GaInAsN/Ge solar cell should be able to reach 40% efficiency if each o... more A four-junction GaInP/GaAs/GaInAsN/Ge solar cell should be able to reach 40% efficiency if each of the junctions can be made with a quality similar to that demonstrated for GaAs. However, the GaInAsN subcell has shown poor performance. Deep-level transient spectroscopy (DLTS) can elucidate recombination centers in a material and could help identify the problem with the GaInAsN. So far, DLTS

A two-junction device consisting of a 1.7-eV GaNPAs junction on a 1.1-eV silicon junction has the... more A two-junction device consisting of a 1.7-eV GaNPAs junction on a 1.1-eV silicon junction has the theoretical potential to achieve nearly optimal efficiency for a two-junction tandem cell. We have demonstrated a monolithic III-V-on-silicon tandem solar cell in which most of the III-V layers are nearly lattice-matched to the silicon substrate. The cell includes a GaNPAs top cell, a GaP-based

A III-V on Si multijunction solar cell promises high efficiency at relatively low cost. The chall... more A III-V on Si multijunction solar cell promises high efficiency at relatively low cost. The challenges to epitaxial growth of high-quality III-Vs on Si, though, are extensive. Lattice-matched (LM) dilute-nitride GaNPAs solar cells have been grown on Si, but their performance is limited by defects related to the nitrogen. Advances in the growth of lattice-mismatched (LMM) materials make more traditional

Acta Palaeontologica Polonica, 2013

Teleosauridae was a group of largely marine Mesozoic crocodylomorphs, typically considered as aki... more Teleosauridae was a group of largely marine Mesozoic crocodylomorphs, typically considered as akin to “marine gavials” due to their elongate, tubular, polydont rostra that are indicative of a piscivorous diet. We here show that these extinct crocodylomorphs were more anatomically, and perhaps ecologically, varied than previously thought. We report the first evidence of denticles in a teleosaurid tooth, revealed by scanning electron microscopic (SEM) analysis of a tooth from the holotype of &amp;quot;Steneosaurus&amp;quot; obtusidens. These denticles are cryptic, because they are microscopic, not contiguous along the carinae (instead forming short series), and are detectable only using SEM. This incipient denticle morphology is similar to that recently discovered in a closely related group of marine crocodylomorphs, the Metriorhynchidae. In particular, the denticulation morphology of &amp;quot;Steneosaurus&amp;quot; is similar to that of the geosaurin metriorhynchid Torvoneustes, indicating that these two taxa may have employed similar feeding styles and that &amp;quot;S.&amp;quot;obtusidens may have been a nearshore ecological analogue to the more offshore, fast-swimming geosaurins. Previous authors have considered &amp;quot;S.&amp;quot; obtusidens and Machimosaurus to be durophagous, but the discovery of denticulated teeth indicates that they had a more varied diet and feeding style, and included flesh slicing as part of their feeding toolkit. It is currently unknown how extensive denticulate carinae may be in Teleosauridae, and we hypothesise that cryptic denticles may also be present in other marine crocodylomorphs once they are subjected to SEM study.

Scottish Journal of Geology, 2015

Royal Society Open Science, 2014

Nature, Jan 2, 2000

T7 DNA polymerase catalyses DNA replication in vitro at rates of more than 100 bases per second a... more T7 DNA polymerase catalyses DNA replication in vitro at rates of more than 100 bases per second and has a 3'-->5' exonuclease (nucleotide removing) activity at a separate active site. This enzyme possesses a 'right hand' shape which is common to most polymerases with fingers, palm and thumb domains. The rate-limiting step for replication is thought to involve a conformational change between an 'open fingers' state in which the active site samples nucleotides, and a 'closed' state in which nucleotide incorporation occurs. DNA polymerase must function as a molecular motor converting chemical energy into mechanical force as it moves over the template. Here we show, using a single-molecule assay based on the differential elasticity of single-stranded and double-stranded DNA, that mechanical force is generated during the rate-limiting step and that the motor can work against a maximum template tension of approximately 34 pN. Estimates of the mechanical ...

Lecture Notes in Computer Science, 2007

Due to their complexity, systems used within Network Centric Warfare and Command and Control are ... more Due to their complexity, systems used within Network Centric Warfare and Command and Control are notoriously difficult to predict. These systems are often influenced by an ever increasing number of dynamic constraints. This dynamic instability causes problems for many traditional normative Human Factors techniques. Cognitive Work Analysis (CWA) is a formative process that focuses on these constraints rather than prescriptive methods of working; this constraint based approach allows the model to handle the unexpected and ...

Pharmacology, 1992

The effects of intravenous administration of adrenoceptor agonists and antagonists on electrocard... more The effects of intravenous administration of adrenoceptor agonists and antagonists on electrocardiographic or blood pressure (BP) functional parameters were assessed in urethane-anesthetized rats. The responses of cardiovascular functional parameters produced by these drugs included: (1) isoproterenol decreased the duration of a whole BP cycle (Wd), duration of the diastolic wave (Dd), peak amplitude of the systolic wave (SYa), amplitude of

This paper reports on the development of a command and control environment that enables experimen... more This paper reports on the development of a command and control environment that enables experimental studies to be conducted into Network Enabled Capability (NEC). The command and control environment comprises a reconfigurable Command Wall, and wireless local area network and reconfigurable wearable computers. The two studies reported in this paper explore communication media (study one) and data source/decay (study two).

Organizational Behavior and Human Decision Processes, 1997