Valley Population Research Articles

How well do the wider public accept integrated flood risk management? An empirical study in two Swiss Alpine valleys

The EU Floods Directive and Swiss water law both stipulate that non-structural prevention measures should be accorded a high priority in risk management. Several studies, have, however, found that, following flood events, the affected population tend to call for massive structural measures. Which factors can help to convince the local public to view integrated risk management more positively? We conducted a household survey in two Swiss Alpine valleys in which a disastrous flood event had taken place two years before. A total of 2100 standardized questionnaires were sent to all households in the Lötschen Valley and to a random sample of the households in the (larger) Kander Valley. The response rate was 30% with 647 completed questionnaires returned. The analysis showed that, after the flood event, the local populations in both valleys mostly favoured traditional measures of hazard control; but support for non-structural prevention measures also appeared to be rather high. A regression analysis revealed that the level of trust in the federal and cantonal authorities, and that of negative emotional experiences during the flood event were the main predictors for this support. Active information behaviour, in contrast, appeared to have only a marginal influence. Interestingly, however, the belief that floods will occur more frequently due to climate change and the support for ecological river management were also found to be relevant predictors. Communicating with the locals about these more graspable issues might be a promising way to increase their support for integrated flood risk management.

Variation in phenology of hibernation and reproduction in the endangered New Mexico meadow jumping mouse (Zapus hudsonius luteus).

Hibernation is a key life history feature that can impact many other crucial aspects of a species’ biology, such as its survival and reproduction. I examined the timing of hibernation and reproduction in the federally endangered New Mexico meadow jumping mouse (Zapus hudsonius luteus), which occurs across a broad range of latitudes and elevations in the American Southwest. Data from museum specimens and field studies supported predictions for later emergence and shorter active intervals in montane populations relative to lower elevation valley populations. A low-elevation population located at Bosque del Apache National Wildlife Refuge (BANWR) in the Rio Grande valley was most similar to other subspecies of Z. hudsonius: the first emergence date was in mid-May and there was an active interval of 162 days. In montane populations of Z. h. luteus, the date of first emergence was delayed until mid-June and the active interval was reduced to ca 124–135 days, similar to some populations of the western jumping mouse (Z. princeps). Last date of immergence into hibernation occurred at about the same time in all populations (mid to late October). In montane populations pregnant females are known from July to late August and evidence suggests that they have a single litter per year. At BANWR two peaks in reproduction were expected based on similarity of active season to Z. h. preblei. However, only one peak was clearly evident, possibly due to later first reproduction and possible torpor during late summer. At BANWR pregnant females are known from June and July. Due to the short activity season and geographic variation in phenology of key life history events of Z. h. luteus, recommendations are made for the appropriate timing for surveys for this endangered species.

Morphometric parameters of individuals of some age states of rare and endemic species Taraxacum kok-saghyz Rodin. from Kazakhstan

Morphometric investigations of some age states of rare, endemic species Taraxacum kok-saghyz Rodin from the family Asteraceae Dumort. carried out in natural populations in valleys of rivers Kegen and Tekes, as well as near Lake Tuzkol of Raiymbek District in Almaty region (Kazakhstan) are given in the article. The maximum was at the virginal age stage in the studied populations. Juvenile, old generative, and subsenile individuals were present sporadically, while senile individuals were absent at all. In transition from immature to middle generative stage, the height of plants increase from 0.5 cm to 7-8 cm, the diameter of crown – from 1.2-1.7 cm to 10 cm, the number of leaves – from 2-3 to 9-11, as well 5-7 flower stalks with length 2,5-12 cm appear.

An unidentified cluster of infection in the Peruvian Amazon region.

Bartonella bacilliformis is the etiological agent of Carrion's disease, which is a neglected disease linked to people in low-socioeconomic populations in Andean valleys. An outbreak of B. bacilliformis was reported in a rural area of the Peruvian Amazon region. The aim of this study was to characterize this outbreak using molecular techniques. Fifty-three blood samples from patients diagnosed with Carrion's disease were analyzed by molecular tools, using both a Bartonella-specific polymerase chain reaction (PCR) and an universal PCR, both based on 16S rRNA gene amplification. Additional water samples from the area were also analyzed. Unexpectedly, the samples were positive only when the universal PCR was used. Although environmental contamination cannot be ruled out, the results showed that Sphingomonas faeni was the possible causative agent of this outbreak, and that water was the most feasible infection source. Diagnosis by clinical criteria or microscopy may lead to misdiagnosis. There is a need to include molecular tools in the routine diagnosis of febrile syndromes, including Carrion's disease.

Ultrafast multi-level logic gates with spin-valley coupled polarization anisotropy in monolayer MoS2.

The inherent valley-contrasting optical selection rules for interband transitions at the K and K′ valleys in monolayer MoS2 have attracted extensive interest. Carriers in these two valleys can be selectively excited by circularly polarized optical fields. The comprehensive dynamics of spin valley coupled polarization and polarized exciton are completely resolved in this work. Here, we present a systematic study of the ultrafast dynamics of monolayer MoS2 including spin randomization, exciton dissociation, free carrier relaxation, and electron-hole recombination by helicity- and photon energy-resolved transient spectroscopy. The time constants for these processes are 60 fs, 1 ps, 25 ps, and ~300 ps, respectively. The ultrafast dynamics of spin polarization, valley population, and exciton dissociation provides the desired information about the mechanism of radiationless transitions in various applications of 2D transition metal dichalcogenides. For example, spin valley coupled polarization provides a promising way to build optically selective-driven ultrafast valleytronics at room temperature. Therefore, a full understanding of the ultrafast dynamics in MoS2 is expected to provide important fundamental and technological perspectives.

Tunneling and Short Channel Effects in Ultrascaled InGaAs Double Gate MOSFETs

Full-band quantum transport simulations are performed to study the scaling of InGaAs MOSFETs. Short-channel effects evoke severe performance degradation in InGaAs MOSFETs and the tunneling leakage further deteriorates their performances. Reducing the body width is shown to suppress the short channel effects. Doping densities show big impacts on device performances. With inhomogeneous doping InGaAs could outperform Si at gate lengths below 15 nm with 5-nm body width. The density of state bottleneck does not affect InGaAs in simulated devices at 0.5 V supply voltage. At the ultrascaled dimensions the full band simulations are essential to capture strong nonparabolic dispersion. Comparison with a multivalley effective mass model shows that the population of higher conduction band valleys contributes to the total current at thin body widths.

The unexpected beneficial effect of the L-valley population on the electron mobility of GaAs nanowires

The impact of the L-valley population on the transport properties of GaAs cylindrical nanowires (NWs) is analyzed by numerically calculating the electron mobility under the momentum relaxation time approximation. In spite of its low contribution to the electron mobility (even for high electron populations in small NWs), it is demonstrated to have a beneficial effect, since it significantly favours the Γ-valley mobility by screening the higher Γ-valley energy subbands.

Social structure varies with elevation in an Alpine ant.

Insect societies vary greatly in social organization, yet the relative roles of ecological and genetic factors in driving this variation remain poorly understood. Identifying how social structure varies along environmental gradients can provide insights into the ecological conditions favouring alternative social organizations. Here, we investigate how queen number variation is distributed along elevation gradients within a socially polymorphic ant, the Alpine silver ant Formica selysi. We sampled low- and high-elevation populations in multiple Alpine valleys. We show that populations belonging to different drainage basins are genetically differentiated. In contrast, there is little genetic divergence between low- and high-elevation populations within the same drainage basin. Thus, elevation gradients in each of the drainage basins represent independent contrasts. Whatever the elevation, all well-sampled populations are socially polymorphic, containing both monogynous (= one queen) and polygynous (=multiple queen) colonies. However, the proportion of monogynous colonies per population increases at higher elevation, while the effective number of queens in polygynous colonies decreases, and this pattern is replicated in each drainage basin. The increased prevalence of colonies with a single queen at high elevation is correlated with summer and winter average temperature, but not with precipitation. The colder, unpredictable and patchy environment encountered at higher elevations may favour larger queens with the ability to disperse and establish incipient monogynous colonies independently, while the stable and continuous habitat in the lowlands may favour large, fast-growing polygynous colonies. By highlighting differences in the environmental conditions favouring monogynous or polygynous colonies, this study sheds light on the ecological factors influencing the distribution and maintenance of social polymorphism.

Drawdown and Dynamics of Groundwater Table in Kathmandu Valley, Nepal

Groundwater resources in Kathmandu valley provide water for human consumption, industry, hotels and agri- culture as well. Rapid urbanization, mushroomed increment in the built up area, overexploitation of surface and ground- water resource, removal of vegetation cover, change in land use pattern, and formation of impervious surface have led the ultimate lowering of groundwater table and minimization of groundwater recharge as well. This study quantifies the drawdown rate along with the groundwater dynamics across the Kathmandu valley, as the valley constitutes mostly of the urban population of Nepal including the capital city. In Kathmandu valley, for domestic purpose as well as the industrial purpose, water has been pumped continuously surpassing the natural recharge. The groundwater table drawdown has been estimated based on the recorded data of average static groundwater table depth and was found to be 0.7249 m in average and linear regression model of drawdown has been depicted along with the associated range of standard deviation. This drawdown has close proximity with the Mexico City alluvial deposit where ground subsidence is nowadays noticeably oc- curring. Similar land subsidence, water pollution and scarcity of water would be the near future consequence in Kath- mandu valley as nearly 50 % of valley population relies on groundwater resources. Similarly, the groundwater dynamics study has shown the shifting of drainage towards southwestern part of Kathmandu valley. Thus Kathmandu valley is in dire need of proper groundwater management execution in order to avoid the hydrological, hydro-geological and environmental impacts of rapid drawdown.

Interannual variation in connectivity and comparison of effective population size between two splittail (Pogonichthys macrolepidotus) populations in the San Francisco Estuary

The discovery of two genetically distinct splittail populations within the San Francisco Estuary, one which spawns in the rivers of the Central Valley and another in the Petaluma and Napa Rivers of the San Pablo Bay, prompted the need to evaluate their degree of connectivity and relative sizes. We genotyped multiple age-0 splittail cohorts using 19 microsatellite loci to assess any spatiotemporal changes in the distribution of the two populations and estimate their effective population sizes (N e). Genetic population assignments demonstrated that while age-0 splittail are predominantly spatially segregated by populations, substantial geographical overlap may occur during years of high precipitation. However, despite this periodic range overlap, the original observed population structure has persisted for nearly a decade which has included a similarly wet year. This suggests that the present population structure will likely persist in the future due to strong philopatry and/or adaptive differences. We also found that N e estimates were generally lower for the San Pablo Bay population than the Central Valley population, which is consistent with the relative amount of habitat availability in the two locations and genetic diversity indices. The relative isolation and apparent lower N e of the San Pablo Bay splittail population indicates a higher vulnerability to extinction. A more consistent monitoring effort of splittail in the Petaluma and Napa Rivers may be necessary in order to better understand the future viability of this less studied population.

The frequency of HLA-B∗57:01 and the risk of abacavir hypersensitivity reactions in the majority population of Costa Rica

HLA-B∗57:01 is a well-known and cost-effective pharmacogenetic marker for abacavir hypersensitivity. As with other HLA alleles, there is widespread variation in its frequency across populations. The Costa Rica Central Valley Population (CCVP) is the major population in this country. The frequency of HLA-B∗57:01 in this population has not been described yet. Thus, our aim was to determine the frequency of this allele in the CCVP. 200 unrelated healthy volunteer donors born in the CCVP were typed. HLA-B∗57-positive samples identified by HLA intermediate resolution typing methods were further typed by SBT to high resolution. An HLA-B∗57:01 carrier frequency of 5.00% was determined in this sample. This frequency is relatively high in comparison to reports from other populations in Latin America. These results suggest that there is a considerable frequency of HLA-B∗57:01 in the CCVP and that pharmacogenetic testing for HIV+ patients who are going to receive abacavir-based treatment should be considered in this country.

Iwo Eleru's place among Late Pleistocene and Early Holocene populations of North and East Africa

The Iwo Eleru site in Nigeria preserves the only terminal Pleistocene fossil from tropical West Africa. The peoples of this region contributed to significant population movements throughout the continent during the Holocene. As such, characterizing the phenotype of Late Pleistocene West African populations is critical for disentangling the evolutionary signatures of a highly complex African population history and structure. Previous research approached the calvaria's morphology from a paleoanthropological perspective, noting its mosaic of archaic and modern neurocranial features and distinctiveness from Pleistocene fossil taxa and contemporary modern human samples. In this paper, I compare Iwo Eleru with contemporary Late Pleistocene Africans and also consider the specimen's affinities with Holocene populations of the central and western Sahara, Nile Valley, and East Africa. Craniometric data were recorded for 22 neurocranial dimensions and subjected to principal components analysis and Mahalanobis distance estimation. Multidimensional scaling of distances indicated that Iwo Eleru fell outside the observed range of variation of other terminal Pleistocene supra-equatorial African populations, confirming previous results that documented its divergence from Neanderthals, Upper Paleolithic Europeans, and modern Africans. The calvaria was also distinct from Holocene Saharan, Nile Valley, and East African populations, which suggests limited West African input into the Sahara during the African Humid Period. Results presented here bolster previous research that suggested Iwo Eleru's anatomy reflected either admixture with archaic humans or the long-term survival of populations with more archaic neurocranial anatomy until the end of the Pleistocene.

Is the Central Valley of Costa Rica a genetic isolate?

In the last decade, the Costa Rican Central Valley population (CRCV), has received considerable scientific attention, attributed in part to a particularly interesting population structure. Two different and contradictory explanations have emerged: (1) An European-Amerindian-African admixed population, with some regional genetic heterocigosity and moderate degrees of consanguinity, similar to other Latin-American populations. (2) A genetic isolate, with a recent founder effect of European origin, genetically homogeneous, with a high intermarriage rate, and with a high degree of consanguinity. Extensive civil and religious documentation, since the settlement of the current population, allows wide genealogy and isonymy studies useful in the analysis of both hypotheses. This paper reviews temporal and spatial aspects of endogamy and consanguinity in the CRCV as a key to understand population history. The average inbreeding coefficients (a) between 1860 and 1969 show a general decrease within time. The consanguinity in the CRCV population is not homogeneous, and it is related to a variable geographic pattern. Results indicate that the endogamy frequencies are high but in general it was not correlated with a values. The general tendency shows a consanguinity decrease in time, and from rural to urban communities, repeating the tendencies observed in other countries with the same degree of development, and follows the general Western World tendency. Few human areas or communities in the world can be considered true genetic isolates. As shown, during last century, the CRCV population has had consanguinity values that definitively do not match those of true genetic isolates. A clear knowledge of the Costa Rican population genetic structure is needed to explain the origin of genetic diseases and its implications to the health system.

Spatially resolving valley quantum interference of a donor in silicon

Electron and nuclear spins of donor ensembles in isotopically pure silicon experience a vacuum-like environment, giving them extraordinary coherence. However, in contrast to a real vacuum, electrons in silicon occupy quantum superpositions of valleys in momentum space. Addressable single-qubit and two-qubit operations in silicon require that qubits are placed near interfaces, modifying the valley degrees of freedom associated with these quantum superpositions and strongly influencing qubit relaxation and exchange processes. Yet to date, spectroscopic measurements have only probed wavefunctions indirectly, preventing direct experimental access to valley population, donor position and environment. Here we directly probe the probability density of single quantum states of individual subsurface donors, in real space and reciprocal space, using scanning tunnelling spectroscopy. We directly observe quantum mechanical valley interference patterns associated with linear superpositions of valleys in the donor ground state. The valley population is found to be within 5% of a bulk donor when 2.85 ± 0.45 nm from the interface, indicating that valley-perturbation-induced enhancement of spin relaxation will be negligible for depths greater than 3 nm. The observed valley interference will render two-qubit exchange gates sensitive to atomic-scale variations in positions of subsurface donors. Moreover, these results will also be of interest for emerging schemes proposing to encode information directly in valley polarization.

The Whiskered Tern Chlidonias hybrida expansion in Poland: the role of immigration

AbstractThe Whiskered Tern population in Poland has rapidly increased from 40 breeding pairs in 1990 to over 1,600 in 2007, with strongest local population in the Upper Vistula River Valley. Owing to rather low pre-breeding and adult apparent survival rates estimated for this population (0.54 and 0.80, respectively) and a delay in accession to reproduction (recruitment completed at age 3), matrix modelling indicated an intrinsic growth rate ofλcalc = 1.02. Observed growth rates of both the Polish and the Upper Vistula River Valley populations wasλobs = 1.29. Using the deterministic population projection matrix including immigrant class, we estimated that, on average, 44 immigrants should enter the Upper Vistula River Valley population annually to match the observed growth. With survival rates increased (ΦP = 0.63,ΦB = 0.90) as to mimic no emigration and reduced dispersal, the estimated number of immigrants was only eight, indicating that substantial emigration rates are likely. A majority of the breeding sites were recorded in man-made water bodies. Colonisation has started in the southeast and proceeded towards the northwest. The strong, stable population in western Ukraine may explain high numbers of immigrants that could originate from there. Other factors favouring quick colonisation of Poland include availability of suitable breeding sites, the wide flexibility of the species with respect to breeding habitat, plentiful food, and high breeding success in the Upper Vistula River Valley. It also seems likely that westward shifts in both breeding and wintering ranges could add to the strong population increases in Eastern Europe.

Using a bioinspired model to determine the extinction risk of Calotriton asper populations as a result of an increase in extreme rainfall in a scenario of climatic change

Climate-induced changes in hydrology are potentially one of the greatest threats to most aquatic-breeding amphibians. Collectively, studies indicate that the frequency of heavy precipitation events (or the proportion of severe rainfall from heavy falls) is expected to increase in most areas during the 21st century. Given these projections, it is pertinent to establish whether Calotriton asper populations have the capacity to withstand an increase in the frequency of extreme rainfall. Building a reliable model is a key step towards understanding the future dynamics of newt populations in a potential scenario of climatic change.We propose a population dynamics P-system model (PDP) for the Pyrenean newt (C. asper) population that takes into account the basic processes of reproduction, mortality, movement via streams and flood risk. With this model, we aim to determine the response of C. asper populations to various hypothetical scenarios of increases in extreme rainfall frequency. Our results show that the proposed PDP model is useful to predict annual fluctuations of C. asper population size and the future evolution of the species.C. asper extinction was predicted in only one scenario in the Pi Valley population. However, a reduction in population levels is observed under all scenarios of increased frequency of extreme rainfall. Consequently, the risk of extinction rises as indicated by an increase in the coefficient of variation. Larval mortality by catastrophic drift is considerable, leading to a lack of recruitment in the third year, the time at which small newts reach sexual maturity and return to the water.

HLA class II alleles in the Otomi population of the Mezquital Valley: a genetic approach to the history of interethnic migrations in the Mexican Central Plateau.

From a historical and genetic point of view, the Otomi of the Mezquital Valley are a frontier people that have played an important role in the population dynamics of the Mexican Central Plateau. Due to the antiquity of their presence in the area, the Otomi may be bearers of ancient genetic variability, shared mainly today with other groups belonging to the Otomanguean linguistic family and with the Nahua. In this study we analyzed the HLA class II allele frequencies reported in Mexican indigenous populations, in order to provide an intraregional-level historical perspective of the genetic relationships between the Otomi of the Mezquital Valley and indigenous populations from other regions of Mexico. We examined genetic variation in HLA-DRB1 and -DQB1 loci in 66 nonrelated individuals belonging to seven indigenous communities from the Ixmiquilpan municipality in the Mezquital Valley, in the State of Hidalgo, Mexico. The variability of the HLA-DRB1 gene among the Otomi of the Mezquital Valley was mainly concentrated in five alleles: -DRB1*08:02 (31.06%), -DRB1*04:07 (25.77%), -DRB1*14:06 (7.55%), -DRB1*14:02 (6.06%), and -DRB1*16:02 (4.55%); these alleles have been previously described in other indigenous populations. The most frequent alleles at the HLA-DQB1 locus were -DQB1*03:02 (34.09%), -DQB1*04:02 (31.03%), and -DQB1*03:01 (19.7%). Furthermore, the HLA-DQB1*02:02 allele was found in the Otomi group with a frequency of 2.27%; this allele has not been reported in Mexican indigenous populations. In conclusion, the genetic constitution of the Otomi population is intermediate to the northern groups and the genetic variability shared by the peoples of the central regions of Mexico. Furthermore, HLA-DRB1 and -DQB1 allelic variability among the Otomi provides insight into the historical processes implied in the biological admixture with European, Asian, and African populations as well as in the admixture with the population of Mexico City associated with long-standing migratory processes.

Many-Body Effects in Valleytronics: Direct Measurement of Valley Lifetimes in Single-Layer MoS2

Single layer MoS2 is an ideal material for the emerging field of "valleytronics" in which charge carrier momentum can be finely controlled by optical excitation. This system is also known to exhibit strong many-body interactions as observed by tightly bound excitons and trions. Here we report direct measurements of valley relaxation dynamics in single layer MoS2, by using ultrafast transient absorption spectroscopy. Our results show that strong Coulomb interactions significantly impact valley population dynamics. Initial excitation by circularly polarized light creates electron-hole pairs within the K-valley. These excitons coherently couple to dark intervalley excitonic states, which facilitate fast electron valley depolarization. Hole valley relaxation is delayed up to about 10 ps due to nondegeneracy of the valence band spin states. Intervalley biexciton formation reveals the hole valley relaxation dynamics. We observe that biexcitons form with more than an order of magnitude larger binding energy compared to conventional semiconductors. These measurements provide significant insight into valley specific processes in 2D semiconductors. Hence they could be used to suggest routes to design semiconducting materials that enable control of valley polarization.

Evaluating Survival of Greater Sage-Grouse Chicks in Strawberry Valley, Utah, by Use of Microtransmitters: Does Handling Time Negatively Influence Survival Rates?

Research indicates that low nest success and juvenile survival may be factors contributing to Greater Sage-Grouse population declines. Recent technological advances in microtransmitters have allowed researchers to monitor individual chicks and broods. We initiated a chick survival study in 2006 and used microtransmitters to (1) examine the viability of using microtransmitters on chicks to assess survival, including the effect of handling time during the suturing process; (2) estimate overall chick survival; and (3) compare chick survival in the Strawberry Valley population to other published reports. We used a known-fate model in program MARK to estimate ĉ (overdispersion), weekly survival rates, and 49-day survival of radio-marked chicks. Chick survival rates were lowest during the initial 3 weeks of life, after which point weekly survival stabilized. Survival over 49 days was estimated at 0.25 (SE 0.10) and was comparable to estimates from other populations. Handling time was negatively associated with chick survival, and chicks were 2 times more likely to survive to 49 days when handled for only 5 minutes instead of 19 minutes. We recommend that researchers be judicious in using microtransmitters and make every effort to reduce handling time during transmitter attachment.

Using scale characteristics and water temperature to reconstruct growth rates of juvenile steelhead Oncorhynchus mykiss

Juvenile steelhead Oncorhynchus mykiss from a northern California Central Valley population were reared in a controlled laboratory experiment. Significantly different rates of growth were observed among fish reared under two ration treatments and three temperature treatments (8, 14 and 20°C). Wider circulus spacing and faster deposition was associated with faster growth. For the same growth rate, however, circulus spacing was two-fold wider and deposited 36% less frequently in the cold compared to the hot temperature treatment. In a multiple linear regression, median circulus spacing and water temperature accounted for 68% of the variation in observed O. mykiss growth. These results corroborate previous research on scale characteristics and growth, while providing novel evidence that highlights the importance of water temperature in these relationships. Thus, this study establishes the utility of using scale analysis as a relatively non-invasive method for inferring growth in salmonids.