The dimension of a formal language

A connection is established between formal language theory and mathematical analysis by associating the symbols of strings of a language with the digits of expansions of points in the unit interval. A language is made to correspond to a particular subset of the unit interval, and the dimension of a language is defined as the Hausdorff dimension of this subset. It is shown that the dimension of a language is less than or equal to its channel capacity, and it is shown that a statement involving the dimension of a language can be added to a list of criteria developed by Brainerd and Knode (1972) for determining that a language is not recognizable by a finite automaton

Growth and Survival of Baldcypress Planted in an Old Ricefield of Coastal South Carolina

Vast acreages of baldcypress [Taxodium distichum (L.) Rich.] swampland in coastal South Carolina were cleared for rice production starting in the late 1600s. When rice cultivation ended in the late 1800s, many cultivated areas becamemarshlands. Other fields failed to return to forest unless they were planted. In one such area, nine acres were planted with baldcypress in 1956 by MeadWestvaco near Walterboro, SC. Seedlings were planted on an 8- by 8-foot spacing. Beginning in November 1991, five 0.12-acre plots were established within the stand to monitor tree growth and survival and measured yearly. In addition to baldcypress, the stand now contains red maple (Acer rubrum L.), black willow (Salix nigra Marsh.), sweetgum (Liquidambar styraciflua L.), and persimmon (Diospyros virginiana L.). The number of trees per acre declined from 600 to 402 by year 2000. Average diameter of trees after 44 years was 9.1 inches. In 2001, MeadWestvaco clearcut half of the stand, thinned 1/4 of the stand, and left 1/4 intact. All stems were removed from the clearcut section, and the thinned section was reduced to 104 stems per acre (88 percent of remaining trees are baldcypress). Five regeneration plots were placed in the clearcut area to follow future regeneration patterns

Restoration of Southern Ecosystems

Restoration of the myriad communities of bottomland hardwood and wetland forests and of the diverse communities of fire-dominated pine forests is the subject of intense interest in the Southern United States. Restoration practice is relatively advanced for bottomland hardwoods and longleaf pine (Pinus palustris Mill.), and less so for swamps and shortleaf pine (P. echinata Mill.). Most bottomland hardwood restoration is taking place on private land, while restoration of swamps and shortleaf pine occurs mostly on public land. Both public and private landowners are involved in the restoration of longleaf pine. Proper matching of species to site is critical to successful restoration of bottomland hardwoods. Techniques for longleaf pine restoration include the reintroduction of growing-season fire and the planting of longleaf pine seedlings and understory species. Safely reintroducing growing-season fire, however, may require initial manipulation of other vegetation by mechanical or chemical means to reduce built-up fuels

Forested Wetlands of the Southern United States: A Bibliography

The term forested wetland covers a variety of forest types including mangroves, cypress/tupelo swamps, bottomland hardwoods, pocosins and Carolina bays, flatwoods, and mountain fens. These forests are dominated by woody species that have morphological features, physiological adaptations, and/or reproductive strategies enabling them to achieve maturity and reproduce in an environment where the soils within the rooting zone may be inundated or saturated for various periods during the growing season. Although alluvial floodplains occur along most streams of the United States, they are most extensive in the Atlantic Coastal Plain, Gulf Coastal Plain, and Mississippi Alluvial Plain. Only about half of the original floodplain forests remained by the 1930s, and conversion to agriculture continued at an accelerated pace during the 1960s and 1970s.The purpose of this bibliography is to provide a detailed listing of references for students and researchers of the varied studies conducted in these forest types

Processes Contributing to Resilience of Coastal Wetlands to Sea-Level Rise

The objectives of this study were to identify processes that contribute to resilience of coastal wetlands subject to rising sea levels and to determine whether the relative contribution of these processes varies across different wetland community types. We assessed the resilience of wetlands to sea-level rise along a transitional gradient from tidal freshwater forested wetland (TFFW) to marsh by measuring processes controlling wetland elevation. We found that, over 5 years of measurement, TFFWs were resilient, although some marginally, and oligohaline marshes exhibited robust resilience to sea-level rise. We identified fundamental differences in how resilience is maintained across wetland community types, which have important implications for management activities that aim to restore or conserve resilient systems. We showed that the relative importance of surface and subsurface processes in controlling wetland surface elevation change differed between TFFWs and oligohaline marshes. The marshes had significantly higher rates of surface accretion than the TFFWs, and in the marshes, surface accretion was the primary contributor to elevation change. In contrast, elevation change in TFFWs was more heavily influenced by subsurface processes, such as root zone expansion or compaction, which played an important role in determining resilience of TFFWs to rising sea level. When root zone contributions were removed statistically from comparisons between relative sea-level rise and surface elevation change, sites that previously had elevation rate deficits showed a surplus. Therefore, assessments of wetland resilience that do not include subsurface processes will likely misjudge vulnerability to sea-level rise

Processes Contributing to Resilience of Coastal Wetlands to Sea-Level Rise

The objectives of this study were to identify processes that contribute to resilience of coastal wetlands subject to rising sea levels and to determine whether the relative contribution of these processes varies across different wetland community types. We assessed the resilience of wetlands to sea-level rise along a transitional gradient from tidal freshwater forested wetland (TFFW) to marsh by measuring processes controlling wetland elevation. We found that, over 5 years of measurement, TFFWs were resilient, although some marginally, and oligohaline marshes exhibited robust resilience to sea-level rise. We identified fundamental differences in how resilience is maintained across wetland community types, which have important implications for management activities that aim to restore or conserve resilient systems. We showed that the relative importance of surface and subsurface processes in controlling wetland surface elevation change differed between TFFWs and oligohaline marshes. The marshes had significantly higher rates of surface accretion than the TFFWs, and in the marshes, surface accretion was the primary contributor to elevation change. In contrast, elevation change in TFFWs was more heavily influenced by subsurface processes, such as root zone expansion or compaction, which played an important role in determining resilience of TFFWs to rising sea level. When root zone contributions were removed statistically from comparisons between relative sea-level rise and surface elevation change, sites that previously had elevation rate deficits showed a surplus. Therefore, assessments of wetland resilience that do not include subsurface processes will likely misjudge vulnerability to sea-level rise

Disparate impacts of the Eldgjá and Laki flood-lava eruptions

The Eldgjá eruption of ~ 939 AD is recognised as the largest in Iceland since Settlement, and ranks among the largest late-Holocene volcanic episodes on Earth. It disgorged > 21.0 km3 (Dense Rock Equivalent) of magma as lava flows (~ 19.7 km3) and tephra deposits (> 1.3 km3 DRE), comprising alternating phreatomagmatic (wet) and magmatic (dry) explosive phases. Tephra deposits up to four metres thick buried proximal areas, and extreme quantities of sulphur and other volatiles were released into the atmosphere. Little is known about the environmental and societal impacts of the eruption within Iceland as it took place during the initial decades of human settlement, and before written record-keeping in Iceland became prevalent. In this work, we review what is known of the Eldgjá eruption, making comparisons with the better documented Laki eruption of 1783–1784 AD (~ 15.1 km3 DRE). While the Eldgjá eruption was volumetrically greater, probably longer-lasting, and involved phreatomagmatic explosive phases, we reason that societal resilience to volcanic hazards was likely stronger in the 10th century compared with the 18th, reflecting differences in social and natural capital in Iceland. Accordingly, the impacts of the Eldgjá eruption cannot be inferred reliably from knowledge of the Laki episode and its aftermath

Inhibition of sodium–glucose cotransporter-2 preserves cardiac function during regional myocardial ischemia independent of alterations in myocardial substrate utilization

The goal of the present study was to evaluate the effects of SGLT2i on cardiac contractile function, substrate utilization, and efficiency before and during regional myocardial ischemia/reperfusion injury in normal, metabolically healthy swine. Lean swine received placebo or canagliflozin (300 mg PO) 24 h prior to and the morning of an invasive physiologic study protocol. Hemodynamic and cardiac function measurements were obtained at baseline, during a 30-min complete occlusion of the circumflex coronary artery, and during a 2-h reperfusion period. Blood pressure, heart rate, coronary flow, and myocardial oxygen consumption were unaffected by canagliflozin treatment. Ventricular volumes remained unchanged in controls throughout the protocol. At the onset of ischemia, canagliflozin produced acute large increases in left ventricular end-diastolic and systolic volumes which returned to baseline with reperfusion. Canagliflozin-mediated increases in end-diastolic volume were directly associated with increases in stroke volume and stroke work relative to controls during ischemia. Canagliflozin also increased cardiac work efficiency during ischemia relative to control swine. No differences in myocardial uptake of glucose, lactate, free fatty acids or ketones, were noted between treatment groups at any time. In separate experiments using a longer 60 min coronary occlusion followed by 2 h of reperfusion, canagliflozin increased end-diastolic volume and stroke volume and significantly diminished myocardial infarct size relative to control swine. These data demonstrate that SGLT2i with canagliflozin preserves cardiac contractile function and efficiency during regional myocardial ischemia and provides ischemia protection independent of alterations in myocardial substrate utilization

Sequencing of Tuta absoluta genome to develop SNP genotyping assays for species identification

Tuta absoluta is one of the most devastating pests of fresh market and processing tomatoes. Native to South America, its detection was confined to that continent until 2006 when it was identified in Spain. It has now spread to almost every continent, threatening countries whose economies rely heavily on tomatoes. This insect causes damage to all developmental stages of its host plant, leading to crop losses as high as 80–100%. Although T. absoluta has yet to be found in the USA and China, which makes up a large portion of the tomato production in the world, computer models project a high likelihood of invasion. To halt the continued spread of T. absoluta and limit economic loss associated with tomato supply chain, it is necessary to develop accurate and efficient methods to identify T. absoluta and strengthen surveillance programs. Current identification of T. absoluta relies on examination of morphology and assessment of host plant damage, which are difficult to differentiate from that of native tomato pests. To address this need, we sequenced the genomes of T. absoluta and two closely related Gelechiidae, Keiferia lycopersicella and Phthorimaea operculella, and developed a bioinformatic pipeline to design a panel of 21-SNP markers for species identification. The accuracy of the SNP panel was validated in a multiplex format using the iPLEX chemistry of Agena MassARRAY system. Finally, the new T. absoluta genomic resources we generated can be leveraged to study T. absoluta biology and develop species-specific management strategies.info:eu-repo/semantics/acceptedVersio

Understanding the yeast host cell response to recombinant membrane protein production

Membrane proteins are drug targets for a wide range of diseases. Having access to appropriate samples for further research underpins the pharmaceutical industry's strategy for developing new drugs. This is typically achieved by synthesizing a protein of interest in host cells that can be cultured on a large scale, allowing the isolation of the pure protein in quantities much higher than those found in the protein's native source. Yeast is a popular host as it is a eukaryote with similar synthetic machinery to that of the native human source cells of many proteins of interest, while also being quick, easy and cheap to grow and process. Even in these cells, the production of human membrane proteins can be plagued by low functional yields; we wish to understand why. We have identified molecular mechanisms and culture parameters underpinning high yields and have consolidated our findings to engineer improved yeast host strains. By relieving the bottlenecks to recombinant membrane protein production in yeast, we aim to contribute to the drug discovery pipeline, while providing insight into translational processes