For instance, some 20,000 years learn more ago people are thought to have introduced a few small mammals to

islands in the Bismarck Archipelago (White, 2004). Island agriculturalists often brought ‘transported landscapes’ along with them, including a suite of domesticated plants and animals that make human colonization signatures on many islands easy to identify (see Kirch, 2000, McGovern et al., 2007 and Zeder, 2008). In the sections that follow, we explore these issues, relying on extensive archeological and ecological research in Polynesia, the Caribbean, and California’s Channel Islands. A key component of our discussion is the importance of how island physical characteristics (size, age, isolation, etc.), in tandem with human decision making, shape ancient environmental developments on islands (Table 1). The Polynesian islands include 10 principal archipelagoes (Tonga, Samoa, Society, Cook, Austral, Tuamotu, Gambier (Mangareva), Marquesas, Hawai’i, and New Zealand) and many other isolated islands within a vast triangle defined by apices at New Zealand, Hawai’i, and Easter Island. Eighteen smaller islands within

Melanesia and Micronesia, known as Polynesian Outliers, are also occupied by Polynesian-speaking peoples. Archeological, linguistic, and human biological research has confirmed that the Polynesian cultures, languages, Crizotinib clinical trial and peoples form a monophyletic group within the larger family of Austronesian cultures, languages, and peoples (Kirch and Green, 2001). The immediate homeland of the Polynesians was situated in the adjacent archipelagoes of Tonga and Samoa (along Depsipeptide with more isolated Futuna and ‘Uvea), which were settled by Eastern Lapita colonists ca. 880–896 B.C. (2830–2846 B.P.; Burley et al., 2012). Ancestral Polynesian

culture and Proto-Polynesian language emerged in this region by the end of the first millennium B.C. (Kirch and Green, 2001). A significant diaspora of Polynesian peoples beginning late in the first millennium A.D. then led to the discovery and colonization of the remainder of the Polynesian triangle and Outliers. The last archipelago to be settled was New Zealand, around A.D. 1280 (Kirch, 2000 and Wilmshurst et al., 2008). The Polynesian islands all lie within Remote Oceania, which had no human occupants prior to the dispersal of Austronesians who possessed outrigger sailing canoe technology, a horticultural subsistence economy, and sophisticated knowledge of fishing and marine exploitation (Kirch, 2000). Ranging in size from diminutive Anuta (0.8 km2) to sub-continental New Zealand (268,680 km2), the Polynesian islands span tropical, subtropical, and temperate climatic zones. They also vary in geological age and complexity, and in their terrestrial and marine ecosystems.

In particular, we are looking at how changes in riparian vegetation can alter the flux of one nutrient, silica, www.selleckchem.com/products/Bortezomib.html in rivers. Rivers are the primary source of silicon to coastal ocean ecosystems, where it is often a limiting nutrient for important groups of phytoplankton – like diatoms and radiolarians – that are the foundation of aquatic food webs. Declines in riverine input of bioavailable silica to coastal ecosystems, in combination with increases in riverine discharge of phosphorus and nitrogen, have been shown to limit diatom growth and allow ‘undesirable’ types of algae to flourish

(Garnier et al., 2010, Lane et al., 2004, Officer and Ryther, 1980 and Smayda, 1990). Bioavailable silica, hereafter Si, includes dissolved silica (DSi) and amorphous particles of silica (ASi) that are relatively soluble,

e.g., siliceous diatom frustules, sponge spicules, and terrestrial plant phytoliths. Mineral silicates like quartz sand and clays are relatively insoluble, and thus are a less significant source of Si to aquatic ecosystems. In recent years, studies have shown that terrestrial plants play a larger CDK inhibitor role in the global silica cycle than had been previously acknowledged (e.g., Conley, 2003, Meunier et al., 2008 and Vandevenne et al., 2012). Specifically, those studies

found that terrestrial vegetation can use and store significant amounts of silica. We surmised that when vegetation is located directly within a river channel, it will also have a substantial impact on silica. This study took place on the Platte River (Nebraska, United States), where an accidental experiment has been underway for more than a century. In the 1900s, river discharge was reduced for agricultural irrigation, leading to an incursion of native Etofibrate vegetation into newly exposed areas of riverbed and the formation of vegetated islands. In 2002, a non-native, invasive grass, Phragmites australis (common reed), first appeared in the river and within just a few years infested >500 km of river corridor ( R. Walters, pers. comm., 2010). Due to its dense growth habit, Phragmites was more effective than the native vegetation at slowing flows and causing fine sediment deposition. Furthermore, Phragmites biomass is relatively rich in silica relative to other plant species ( Struyf et al., 2007b), making it an effective “Si-bioengineer” ( Viaroli et al., 2013). The combination of Phragmites-generated biomass and its shedding onto stable islands could cause Si to continuously accumulate and thus deprive the flow of its equilibrium concentration.

, 2011). It has been hypothesized that OROV persists in sylvatic endemic cycles of transmission, although these remain poorly characterized and may involve multiple vectors and reservoir hosts (Pinheiro et al., 1981a). Investigation of candidate vector(s) has centered upon mosquitoes, but although isolations of OROV have been made from Aedes serratus and Coquillettidia venezuelensis ( Anderson et Epacadostat research buy al., 1961 and Pinheiro et al., 1981a), the number of successful recoveries of the virus has been

extremely low. The challenge of making positive isolations of OROV from adult vectors under endemic scenarios is illustrated by the isolation of only a single strain of the virus from processing over 1 million mosquitoes, phlebotomine sandflies, ticks and other ectoparasites in the Amazon region during inter-epidemic periods ( Pinheiro et al., 1981a). Screening of potential reservoir hosts for OROV has also been undertaken but remains inconclusive, with antibodies to infection detected in a wide range of domestic and wild avian species, primates, wild carnivores and rodents ( Batista et al., 2012 and Pinheiro et al., 1981a). Isolations of OROV, that may be indicative of a transmissible check details viraemia, have also been made from a sloth Bradypus tridactylus ( Pinheiro et al., 1962) and a sylvatic monkey Callithrix sp. ( Nunes et al., 2005). Replication and concurrent clinical signs also occur in the golden hamster (Mesocricetus auratus),

which is currently used as an experimental model ( Pinheiro et al., 1982 and Rodrigues et al., 2011). Interestingly, the ability of OROV to replicate in livestock appears not to have been addressed in studies to date, as major outbreak areas of disease have not coincided

with centers of ruminant production. In contrast to the theoretical sylvatic cycle, epidemic transmission of OROV between humans as an anthroponosis are well characterized, being driven almost exclusively by C. paraensis. The role of this species as a vector of OROV has been investigated in both the field ( Roberts et al., 1981) and in the laboratory ( Pinheiro et al., 1982 and Pinheiro et al., 1981b). The latter studies are notable for convincingly demonstrating biological transmission of OROV between hosts by Culicoides and are among the most complete vector competence trials of the genus. Larvae of C. paraensis develop in microhabitats of decomposing banana and plantain stalks and stumps and cacao Demeclocycline hulls ( Hoch et al., 1986) ( Fig. 1F), having originally exploited rotting organic material in dry tree-holes, leaf debris and damp soil for this purpose ( Mercer et al., 2003, Pappas et al., 1991 and Wirth and Felippe-Bauer, 1989). Following fruit harvesting, these waste products accumulate in close proximity to high-density human housing, resulting in biting attacks ofC. paraensis adult females on inhabitants. Unlike the majority of other Culicoides species that have a primarily crepuscular (dusk and dawn) periodicity ( Kettle, 1977 and Mellor et al.

The gas inspired into the alveolar compartment is in two parts: the first comes from the dead space compartment, and the second is fresh inspired gas. FIA,n(t)

also therefore consists of two parts: the first part has a value of FA,n−1 since this was the alveolar concentration of indicator gas from the previous SCH727965 order breath which now resides in the dead space; the second part has a value of FI,n(t), the concentration of the indicator gas measured by the concentration sensor at the mouth during inspiration of breath n. Here we have made the distinction between indicator gas concentration in the lung and that at the mouth, and therefore FIA,n(t) can be expressed as equation(16) FIA,n(t)=FA,n−1iftbI≤t

dead space during inspiration of breath n. Substituting (16) into (15), we have equation(17) VI=∫tbItbI+TDIV˙(t)FA,n−1dt+∫tbIteI−TDIV˙(t)FI,n(t)dt=VDFA,n−1+∫tbIteI−TDIV˙(t)FI,n(t)dt Here we have arrived at an expression for VIVI. Now we seek to find an expression for VEVE and VQVQ, to complete the conservation of mass equation (14). In the above analysis of the first part of F  IA,n(t  ) in (16), we have assumed that F  A,n (the indicator gas concentration in the lung during breath n  ) is constant during any breath n  ; this means that F  A,n is equal to FE′,nFE′,n (the measured indicator gas concentration at the end of expiration in breath n). That is, equation(18) Screening Library FA,n=FE′,nFA,n=FE′,n The reason for using FE′,nFE′,n here is that it is more readily measured than F  A,n. FE′FE′ (the function of FE′,nFE′,n over all breaths) is a sine wave expressed in Eqs. (25) and (26), using our indicator gas injection method in Section  3.2. Eq. (18) implies that FA (the function of the indicator gas concentration in the lung from all breaths) is also a sine wave. The

expired indicator gas volume VEVE can be expressed as equation(19) VE=VT,nFA,n,VE=VT,nFA,n,where VT,n is the tidal volume (the Clomifene volume of gas inhaled and exhaled) during breath n. Substituting (18) into (19) gives the final expression for VEVE equation(20) VE=VT,nFE′,n.VE=VT,nFE′,n. The uptake of the indicator gas VQVQ is equation(21) VQ=Q˙Pλb(FA,n−FV¯,n)Tn,where Q˙P is the pulmonary blood flow, λ  b is blood solubility coefficient of the indicator gas, and T  n is the duration of breath n  . FV¯,n is the average indicator gas concentration returned to the lung through venous recirculation in breath n. Some of the inspired indicator gas is taken up by the pulmonary capillary blood in the lung, and eventually returns to the lung via venous recirculation. Previous research has shown that at carefully chosen forcing frequencies, the venous recirculation effects can be ignored (Hahn et al.

3). These results suggest that KRG prevents Dex-induced apoptosis in MC3T3-E1 cells in a dose-dependent manner. Apoptosis is a regulated cellular suicide mechanism that was characterized by nuclear condensation, cell shrinkage, and DNA fragmentation. The increase in MC3T3-E1 cell viability upon treatment with both KRG and Dex suggests that KRG modulates the expression of cell death-related INCB018424 manufacturer genes. Caspases, a family of cysteine proteases, are the central regulators of apoptosis. To examine the possibility that the expression of these proteins may be modulated, expression levels of both proapoptotic genes (caspase-3, -6, -7, and -9) and antiapoptotic genes (BCL-2, IAPs, and XIPA) were confirmed by

quantitative real-time PCR. The treatment of MC3T3-E1 cells with 100μM Dex for 48 h increased the mRNA levels of caspases, whereas cells exposed to Dex and KRG decreased the mRNA levels of caspase-3 and caspase-9 ( Fig. 4). However, Dex failed to repress the expression of antiapoptotic genes (BCL-2, IAPs, and XIPA). In fact, Dex significantly upregulated the expression of Bcl-XL, IAP-2, and XIAP ( Fig. 5). Therefore, Dex EGFR phosphorylation may induce apoptosis by upregulating proapoptotic gene expression. To survey the molecular mechanism by which KRG exerts its antiapoptotic effects, activation of the MAPK/AKT signaling pathway was examined. MC3T3-E1 cells were incubated with 100μM Dex in the presence

or absence of KRG (1 mg/mL) for 24 h. The JNK, p38, and AKT activation states were reviewed by Western blot analysis. When cells were exposed to 100μM Dex, the

JNK phosphorylation level increased significantly compared to that of the control, whereas it decreased significantly when treated with both Dex and KRG. Given that AKT activation protects cells from cell apoptosis and cell death, we also investigated whether KRG could induce AKT phosphorylation in Dex-exposed MC3T3-E1 cells or not. When cells were exposed to 100μM Dex, AKT phosphorylation decreased significantly 4-Aminobutyrate aminotransferase compared to that of the control, whereas it increased significantly when cells were treated with both Dex and KRG (Fig. 6). To determine the effects of KRG on the expression of osteogenic gene markers and ALP activity, cells were treated with various concentrations of KRG and Dex in osteogenic differentiation conditions for 5 d and 7 d. Osteoblastic differentiation was assessed by using quantitative real-time PCR, by measuring the mRNA expression levels of ALP, bone morphogenic proteins (BMPs), osteopontin (OPN), RUNX2, and osteocalcin (OCN). DEX-treated cells showed decreased ALP activity, but in cells treated with Dex and KRG (30 μg/mL and 60 μg/mL; Fig. 7A) this activity was increased significantly. Based on quantitative real-time PCR, cells treated with 100μM Dex exhibited decreased mRNA expression levels of ALP, OCN, OPN, RUNX2, BMP-2, -6, -7, and -9, whereas these expression levels increased in cells treated with both Dex and KRG (Fig.

A full review of the evidence for these impacts from throughout Polynesia is beyond the scope of this article. Here we limit our review to the archeological and paleoecological evidence for transformation—from pristine ecosystems to anthropogenic landscapes—of three representative Polynesian islands and one archipelago: Tonga, Tikopia, Mangaia, and Hawai’i. Burley et al. (2012) pinpointed the initial human colonization of Tongatapu Island, using high-precision U–Th dating, to 880–896 B.C. From this base on the largest island

of the Tongan archipelago, Lapita peoples rapidly explored and established small settlements throughout the Ha’apai and Vava’u islands to the north, and on isolated Niuatoputapu (Kirch, 1988 and Burley et al., 2001). This rapid phase of discovery and colonization is archeologically attested by small hamlet sites containing distinctive Early Eastern Lapita pottery. Excavations in these hamlet sites and in the more MEK inhibitor extensive middens that succeeded them in the Ancestral Polynesian period (marked by distinctive Polynesian Plain Ware ceramics) reveal a sequence of rapid impacts on the indigenous and endemic birds and reptiles (Pregill and Dye, 1989), including the local extinction of an iguanid lizard, megapodes, and other birds (Steadman, 2006). Burley (2007) synthesized settlement-pattern data from Tongatapu, Ha’apai,

and Vava’u to trace the steady growth of human populations, demonstrating that by the Polynesian Plainware phase (700 B.C. to A.D. 400) these islands were densely settled. The selleckchem intensive dryland agricultural systems necessary to support such large populations NVP-BGJ398 concentration would have transformed much of the raised limestone landscapes of these “makatea” type islands into a patchwork of managed gardens and secondary growth. Historically, native forest is restricted to very small areas on these islands, primarily on steep terrain not suitable for agriculture.

The prehistory and ecology of Tikopia, a Polynesian Outlier settled by a Lapita-pottery making population at approximately the same time as Tongatapu (ca. 950 B.C.), was intensively studied by Kirch and Yen (1982). As in the Tongan case, the initial phase of colonization on this small island (4.6 km2) was marked by a significant impact on the island’s natural biota, including extirpation of a megapode bird, introduction of rats, pigs, dogs, and chickens, and presumably a suite of tuber, fruit, and tree crop plants. The zooarchaeological record exhibits dramatic declines in the quantities of fish, mollusks, sea turtles, and birds over the first few centuries, the result of intensive exploitation (Kirch and Yen, 1982 and Steadman et al., 1990). Pigs, which were introduced at the time of initial colonization, became a major food source during the first and early second millennia A.D., but were extirpated prior to European contact.

g., Oosterberg and Bogdan, 2000). In the Mississippi delta, nutrient excess delivered via diversions to freshwater marshes have been blamed for their apparent

vulnerability to hurricanes (e.g., Kearney selleck et al., 2011). For successful schemes of channelization, a comprehensive adaptive management plan for water, sediment and nutrients would be needed to protect the ecological characteristics in addition of maintaining the physical appearance of the delta plain. If increases in the sediment trapped on the fluvial delta plain may aid to balance the effects of sea level rise, a similar approach for the external, marine delta plain would completely change the landscape of that region. Composed of fossilized sandy beach and barrier ridges that receive little new sand once encased on the delta plain, the marine delta would be transformed by channelization into an environment akin to the fluvial delta with lakes and marshes. In the absence of other solutions, such as hard protection dikes and short of abandonment, channelization could potentially raise the ground locally on these strandplains and barrier plains. Instead, with no new sediment input, the marine delta would

in time result in its partial drowning; sand ridge sets of higher relief will transform into barrier systems and thus, with water on both sides, become dynamic again rather than being fossilized on the delta plain. This will provide in turn some protection to the remaining GW-572016 concentration mainland delta coast because Tolmetin dynamic barrier systems with sand sources nearby (i.e., the delta lobes themselves) are

free to adjust to dynamic sea level and wave conditions by overwash, foredune construction, and roll over. However, it is clear that the most vulnerable part of the Danube delta is the deltaic coastal fringe where most of sediment deficit is felt. In order to tackle erosion along the delta coast, a series of large scale diversion solutions have been proposed since the early 20th century (see e.g., compilation by Petrescu, 1957). However, the entire Danube currently debouches only about half the amount of sediment that Chilia distributary used to deliver annually to construct its lobe in pre-damming era! Our study suggests instead that small but dense diversions similar to the natural Chilia secondary channels, thus another type of channelization mimicking natural processes, may minimize erosion in the nearshore. Hard structures such as breakwaters and groins that curtail offshore and alongshore sediment loss may also provide some temporary, if imperfect, relief. However, waves along the coast of Danube delta are a very efficient and relentless sediment redistribution machine, and in the long run erosion will remain a problem. Erosion of moribund lobes, such as it appears to be the case with the current St. George lobe, can provide enough sand if it is abandoned. Reworking of the St.

One, which Gould designated as “substantive,” makes ontological claims about the world, in that presumptions are made about how nature actually is, e.g., its processes change relatively slowly

and are uniform over time and space. The other class of claims is methodological, in that injunctions or suggestions are made, ATR inhibitor based on present-day observations, to apply that present-day process understanding to conditions in the past (or future). In their recent paper Knight and Harrison (2014) observe that substantive uniformitarianism, which they define as “the Principle of Uniformitarianism” or as “the ‘strong’ principle or doctrine developed by Hutton and later by Lyell” (Camandi, 1999), has been largely discredited by Gould (1965) and others. They note that the many previous criticisms of uniformitarianism have focused on the research approach rather than on the research object. They define the latter as “Earth’s physical systems,” and they claim that this, “…cannot be meaningfully investigated using a uniformitarian approach Because uniformitarianism Ceritinib ic50 was formulated prior to the understanding of Earth in “systems” terms, it is well to be clear in what is meant by the latter. A “system” is a structured set of objects and relationships among those objects. Is Earth the exact same thing as

“Earth systems” (e.g., Baker, 1996a)? Earth systems involve those structures that scientists deem to Anidulafungin (LY303366) represent what is important for being monitored, modeled, etc. in order to generate predictions. Earth itself has much more complexity (with humans or without) to be studied in its complete totality without some simplification

into what its human interpreters designate as its “systems.” Physical scientists do not measure everything because such a task would be impossible. Physicists, in particular, measure what they deem to be critical for achieving a system-based understanding. The deductions that can be made (they are loosely termed “predictions”) from this understanding (physical theory) are only possible because assumptions have been made so that results can then be deduced from those assumptions. These assumptions include whatever gets chosen to constitute the “system” to be monitored, modeled, etc. Defining the methodological form of uniformitarianism as “the weak viewpoint that observations of those processes operating upon the Earth can be used to interpret processes and products of the geological past, and vice versa,” Knight and Harrison (2014) offer the following reasons to reject uniformitarianism (with systems-related terms highlighted in bold): 1. “…it does not account for the dominant role of human activity in substantively changing the behavior of all Earth systems, and the significant and very rapid rates of change under anthropogenic climate forcing.

4). The site of Huapula, or Sangay, as the first excavator called it, appears to be an organized, urban-scale residential and ceremonial center. There is no topographic instrument-map of the mound complex at Sangay yet, but sketch maps show a monumental nucleus surrounded by numerous smaller mound groups. A system of roads connects the mound clusters, and the nucleus has complicated formal arrangements of mounds and spaces, sunken plazas, and terraces. The majority of the surrounding

mounds seem to be rectangular, but many are composites grouped around platforms, sometimes with a small mound at the center. The mounds have well-defined strata, black and dark brown anthropic soil middens (see Section ‘Anthropic Alpelisib solubility dmso black soils’), post-molds, burials, and hearths. Large numbers of fine art objects of the Upano and Huapula phases have been dug up, including incised and painted pottery, pottery figurines, stone sculptures, and tools, most with Amazonian stylistic links. Local pottery was traded

into the Andes, however, and shell from the Pacific was traded in. The dates of the Ecuadorian mounds are Formative, between about 1400 and 2500 years ago, which is the period when pottery was introduced from Amazonia to the Andes. After more than a thousand years, the Sangay complex proper was abandoned after a major volcanic ash-fall. Had this Angiogenesis inhibitor site not had prominent mounds and been cut for pasture, it could have

gone unnoticed. The existence of this sophisticated, long-lived mound culture in terra firme was a development not predicted by the environmental limitation theory, and its location in the western Amazon conflicts with assumptions of sparse human occupations in western Amazonia ( McMichael et al., 2012). The mounds are densely distributed over a zone of at least 12 km2, indicating a substantial and dense human population. Pollen studies of lakes in the Ecuadorian Amazon document significant maize cultivation during the last 3000 years in the general Cyclooxygenase (COX) area ( Bush et al., 1989 and Piperno, 1990). In addition to several maize specimens from jars at Sangay, carbonized pits of diverse forest fruits: the tree legume genus Inga (Fabaceae), with abundant sweet aril, the tart-sweet Prunus and Rubus (Rosaceae) and the pharmacoactive vine fruit Passiflora (Passifloraceae), suggest a mixed diet of forest and orchard fruits and field crops. The significant regional prehistoric landscape development via mounds in the tropical forest at Sangay is the earliest known in the Amazon so far. Vegetation and surface sediments within this large mound zone, like parts of the Brazilian Amazon, were heavily altered by prehistoric humans, and the alterations continue to influence the landscape today.

They are also epistemological, in that they seem appropriate or useful to invoke in some form in order to have any chance at all for achieving knowledge. It is for these reasons that the highly respected analytical philosopher Goodman (1967, p. 93) concluded, ‘The Principle of Uniformity dissolves into a principle of selleck chemicals llc simplicity that is not peculiar to geology but pervades all science and even daily life.” For example, one must assume UL in order to land a spacecraft at a future time at a particular spot on Mars, i.e., one assumes that the laws

of physics apply to more than just the actual time and place of this instant. Physicists also assume a kind of parsimony by invoking weak forms UM and UP when making simplifying assumptions about the systems that they choose to model, generating conclusions by deductions from these assumptions combined with physical laws. In contrast, the other forms of uniformitarianism (UK, UD, UR, and US) are all substantive, or ontological, in that they claim a priori how nature is supposed to be. As William Whewell pointed out in his 1832 critique of Lyell’s Principles, Galunisertib research buy it is not appropriate for the scientist to

conclude how nature is supposed to be in advance of any inquiry into the matter. Instead, it is the role of the scientist to interpret nature (Whewell is talking about geology here, not about either physics or “systems”), and science for Whewell is about getting to the correct interpretation. Many geologists continue to be confused by the terms “uniformity of nature” and “uniformitarianism.” Of course, Liothyronine Sodium Whewell introduced the latter to encompass all that was being argued in Lyell’s

Principles of Geology. In that book Lyell had discussed three principles ( Camandi, 1999): (1) the “Uniformity Principle” (a strong version of UM or UP) from which Lyell held that past geological events must be explained by the same causes now in operation, (2) a Uniformity of Rate Principle (UR above), and (3) a Steady-State Principle (US above). Lyell’s version of the “Uniformity Principle” is not merely methodological. It is stipulative in that it says what must be done, not what may be done. Indeed, all of Lyell’s principles are stipulative, with number one stipulating that explanations must be done in a certain way, and numbers two and three stipulating that nature/reality is a certain way (i.e., these are ontological claims). Using Gould’s (1965) distinctions, uniformity of law and uniformity of process are methodological (so long as we do not say “one must”), and uniformity of rate and of state are both stipulative and substantive. There is also the more general view of “uniformity of nature” in science, holding uniformity to be a larger concept than what is applicable only to the inferences about the past made by geologists.