Academic literature on the topic 'Proxy pullback of lenses'

Measurement of light intensity transmission was carried out on an ice core S100 from coastal Dronning Maud Land (DML). Ice lenses were observed in digital pictures of the core and recorded as peaks in the light transmittance record. The frequency of ice layer occurrence was compared with climate proxy data (e.g. oxygen isotopes), annual accumulation rate derived from the same ice core, and available meteorological data from coastal stations in DML. The mean annual frequency of melting events remains constant for the last ∼150 years. However, fewer melting features are visible at depths corresponding to approximately 1890–1930 AD and the number of ice lenses increases again after 1930 AD. Most years during this period have negative summer temperature anomalies and positive annual accumulation anomalies. The increase in melting frequency around ∼1930 AD corresponds to the beginning of a decreasing trend in accumulation and an increasing trend in oxygen isotope record. On annual time scales, a relatively good match exists between ice layer frequencies and mean summer temperatures recorded at nearby meteorological stations (Novolazarevskaya, Sanae, Syowa and Halley) only for some years. There is a poor agreement between melt feature frequencies and oxygen isotope records on longer time scales. Melt layer frequency proved difficult to explain with standard climate data and ice core derived proxies. These results suggest a local character for the melt events and a strong influence of surface topography.

Individuals with profound motor, communication, and/or cognitive impairments may face difficulties describing subjective or experiential information through (i) speech, (ii) writing using a pencil and paper, and (iii) typing using a standard computer keyboard. Although patient-reported outcome measures and patient-reported experience measures can capture information about this group through proxy-report, we cannot solely rely on the responses of a single proxy for experiential information. Research methods to understand the experiences of individuals with profound motor, communication and cognitive impairments are not well defined in the literature. Purpose: To provide guidance to disability researchers on how to explore the subjective and personal experiences, of individuals with profound, motor, communication, and/or cognitive impairments. Three axes are proposed as important to the structure of the “recreated experiences” method: (i) informants, (ii) data collection methods, and (iii) analyses and reflexivity. Different types of information can be gained by involving different informant groups in research about the central person’s experience. Primary guardians can provide information about interpreting central persons’ indicators of expression and broad assessments of their personal life. Other adults can provide insight relative to the central person’s capacities outside of the primary guardian-central person dyad. Peers can provide insight about personal characteristics (i.e., personality traits). Utilizing different data collection methods can foster manifest and latent content to emerge. Analyses and reflexivity which involve diverse perspectives are essential to ensure findings are grounded in lived experience and professional lenses. The method highlights the importance of furthering research to understand the experiences of individuals who cannot traditionally self-express, which may influence possibilities for enhancing care, participation opportunities, and overall well-being.

During recent decades, stable oxygen isotopes derived from tree-ring cellulose (δ18OTRC) have been frequently utilised as the baseline for palaeoclimatic reconstructions. In this context, numerous studies take advantage of the high sensitivity of trees close to their ecological distribution limit (high elevation or high latitudes). However, this increases the chance that indirect climatic forces such as cold ground induced by permafrost can distort the climate-proxy relationship. In this study, a tree stand of sub-alpine larch trees (Larix decidua Mill.) located in an inner alpine dry valley (Val Bever), Switzerland, was analysed for its δ18OTRC variations during the last 180 years. A total of eight L. decidua trees were analysed on an individual base, half of which are located on verified sporadic permafrost lenses approximately 500 m below the expected lower limit of discontinuous permafrost. The derived isotope time series are strongly dependent on variations in summer temperature, precipitation and large-scale circulation patterns (geopotential height fields). The results demonstrate that trees growing outside of the permafrost distribution provide a significantly stronger and more consistent climate-proxy relationship over time than permafrost-affected tree stands. The climate sensitivity of permafrost-affected trees is analogical to the permafrost-free tree stands (positive and negative correlations with temperature and precipitation, respectively) but attenuated partly leading to a complete loss of significance. In particular, decadal summer temperature variations are well reflected in δ18OTRC from permafrost-free sites (r = 0.62, p < 0.01), while permafrost-affected sites demonstrate a full lack of this dependency (r = 0.30, p > 0.05). Since both tree stands are located just a few meters away from one another and are subject to the same climatic influences, discrepancies in the isotope time series can only be attributed to variations in the trees’ source water that constraints the climatic fingerprints on δ18OTRC. If the two individual time series are merged to one local mean chronology, the climatic sensitivity reflects an intermediate between the permafrost-free and –affected δ18OTRC time series. It can be deduced, that a significant loss of information on past climate variations arises by simply averaging both tree stands without prior knowledge of differing subsurface conditions.

The Mediterranean has never been, conceptually or politically, a homogenous and organic space. From antiquity till the modern era, the surrounded littoral nations looked at their neighborhood through the lenses of a cooperative Euro-Mediterranean region, seeking to extend their norms, rules, and values through the deployment of soft power, from trade and aid to security cooperation and political dialogue. Today, instead, there is a great power competition that divided the region between North Africa and the Middle East especially in the eastern Mediterranean, heavily prioritizing the latter over the former in diplomatic and military outreach and viewing it through the prism of the strategic relationship, of EU nations and NATO allies. In addition, the Arab state system of the region is in standoff now, with many (if not most) states featuring existential fragilities or have collapsed altogether. State fragility has created areas of limited statehood, in which alternative forms of governance—from militias to municipalities, international donors to civil society—have stepped in and in which foreign powers have meddled. Through such interference, global and regional rivalries have exacerbated and have found fertile ground. All major global and regional cleavages are now tragically on display in the region: from the Russia-West and Israel-Iran confrontation in Syria to the Turkish-Greece tensions in the Eastern Mediterranean, from the Turkey-UAE/Egypt struggle over political Islam in Libya, to the Iran-Saudi conflict in Yemen, or the Gulf and Israeli skepticism of the Iran nuclear deal. Also, energy has become a proxy for confrontation—as evident in the configuration of the East Med Gas Forum from which Turkey is excluded—and migration has become both a dramatic consequence of fragility and conflict, as well as a tool through which origin and transit countries have arm-twisted Europe. The only cleavage that appears to have temporarily abated is the Arab-Israeli one, with the Abraham accords crystallizing normalization between Israel and some Arab states. Consequently, the region has become far more porous than it once was. It has become impossible to read conflicts in the Mediterranean in isolation, as regional powers like Libya, Egypt, Lebanon, Israel, Cyprus, Greece, France, and Turkey weigh in across the region. Likewise, illegal migration, energy, security, terrorism, and climate dynamics have generated indissoluble ties to the Eastern Mediterranean and the broader Middle East.

The layered sequences of melt features preserved in inland polar ice sheets provide valuable proxy data on past variations in summer temperature. A continuous detailed light-table examination was made on the 2037 m-deep Dye 3 ice core immediately after core recovery. Melt features are products of high air temperatures or solar insolation which occur only at or near the snow surface during summer months. A correlation is made between these features and the extent and intensity of summer temperatures. Care must be exercised to identify and distinguish between all mm-thick radiation crusts and wind crusts contained in the record. The absence or presence of these discrete features serve respectively as indicators of total summer cloud cover and the extent of winter storm activity although they are difficult to differentiate from only light-table observations. In this analysis both thin radiation crusts and wind crusts are not in themselves significant indicators of long-term temperature trends, but may serve as incipient subsurface horizons or barrier crusts for the formation of thicker ice melt features caused by downward melt percolation during elevated surface temperature conditions.More than 10 000 individual melt features, including ice layers, ice lenses and ice wedges (but excluding ice glands) were measured down to a depth of 1278 m; below this depth transformation of air bubbles to transparent air hydrate inclusions occurs (Shoji and Langway, 1987) and the megascopic melt features become obscure. The melt-feature data extends back to 1883 B.c. or approximately 3900 years B.P., based on the accurate time scale of continuous δ18O measurements (Dansgaard and others, 1985) For the entire core profile investigated the annual melt percentage is 5.7. Individual melt features range in thickness from 1 mm to 100 mm. A mean value for melt-feature thickness was calculated for continuous 30-year time intervals to consider the general long-term summer temperature trends with corrections made for progressive annual accumulation layer thinning due to ice flow.Since the AMP parameter includes noise from radiation and wind crusts it appears that the simple average of melt-feature thickness per longer time-units is a better indication of air temperature paleodata. The average melt-feature thickness is 1.2 cm. The complete curve obtained shows a higher thickness value of about 1.5 cm for the period 1800 B.C. to 1300 B.C. A lower, almost constant thickness value of about 1cm is shown for the period 1000 B.c. to 1800 A.D., with a slight reduction in thickness recorded around 200 B.C., 400 A.D. and 1600 A.D. These long-term trends are coherent with those recorded in the δ18O profile for the same ice core.

The layered sequences of melt features preserved in inland polar ice sheets provide valuable proxy data on past variations in summer temperature. A continuous detailed light-table examination was made on the 2037 m-deep Dye 3 ice core immediately after core recovery. Melt features are products of high air temperatures or solar insolation which occur only at or near the snow surface during summer months. A correlation is made between these features and the extent and intensity of summer temperatures. Care must be exercised to identify and distinguish between all mm-thick radiation crusts and wind crusts contained in the record. The absence or presence of these discrete features serve respectively as indicators of total summer cloud cover and the extent of winter storm activity although they are difficult to differentiate from only light-table observations. In this analysis both thin radiation crusts and wind crusts are not in themselves significant indicators of long-term temperature trends, but may serve as incipient subsurface horizons or barrier crusts for the formation of thicker ice melt features caused by downward melt percolation during elevated surface temperature conditions. More than 10 000 individual melt features, including ice layers, ice lenses and ice wedges (but excluding ice glands) were measured down to a depth of 1278 m; below this depth transformation of air bubbles to transparent air hydrate inclusions occurs (Shoji and Langway, 1987) and the megascopic melt features become obscure. The melt-feature data extends back to 1883 B.c. or approximately 3900 years B.P., based on the accurate time scale of continuous δ18O measurements (Dansgaard and others, 1985) For the entire core profile investigated the annual melt percentage is 5.7. Individual melt features range in thickness from 1 mm to 100 mm. A mean value for melt-feature thickness was calculated for continuous 30-year time intervals to consider the general long-term summer temperature trends with corrections made for progressive annual accumulation layer thinning due to ice flow. Since the AMP parameter includes noise from radiation and wind crusts it appears that the simple average of melt-feature thickness per longer time-units is a better indication of air temperature paleodata. The average melt-feature thickness is 1.2 cm. The complete curve obtained shows a higher thickness value of about 1.5 cm for the period 1800 B.C. to 1300 B.C. A lower, almost constant thickness value of about 1cm is shown for the period 1000 B.c. to 1800 A.D., with a slight reduction in thickness recorded around 200 B.C., 400 A.D. and 1600 A.D. These long-term trends are coherent with those recorded in the δ18O profile for the same ice core.

The amount of silt and clay available to rivers reflects source-terrain composition and weathering and can be a primary control on the form and dynamics of channel networks. Fine sediment also affects the permeability of buried fluvial reservoirs. Despite this significance, there is currently a lack of methods for reconstructing how much fine sediment was transported by ancient rivers. Mud accumulations in sandy river deposits are often interpreted as indicators of variable flow conditions; however, these deposits may present an opportunity to constrain how much fine sediment was transported through ancient rivers. We report results from a series of experiments designed to evaluate how much clay and silt are preserved in sandy riverbed deposits under constant and variable discharge conditions. Our results demonstrate that (1) mud deposits, including drapes and lenses, form readily under constant, high-discharge conditions, (2) the amount of fine sediment recovered from bed-material deposits increases as fine-sediment supply increases, and (3) fine-sediment retention is higher during bed aggradation than during bypass conditions. These results indicate that the net retention of clay and silt in sandy riverbed deposits may be a simple but powerful proxy for comparing the overall amount of fine sediment supplied to ancient rivers.

Abstract We use weak lensing observations to make the first measurement of the characteristic depletion radius, one of the three radii that characterize the region where matter is being depleted by growing haloes. The lenses are taken from the halo catalog produced by the extended halo-based group/cluster finder applied to DESI Legacy Imaging Surveys DR9, while the sources are extracted from the DECaLS DR8 imaging data with the Fourier_Quad pipeline. We study halo masses 12 &lt; log (Mgrp [M⊙/h]) ≤ 15.3 within redshifts 0.2 ≤ z ≤ 0.3. The virial and splashback radii are also measured and used to test the original findings on the depletion region. When binning haloes by mass, we find consistency between most of our measurements and predictions from the CosmicGrowth simulation, with exceptions to the lowest mass bins. The characteristic depletion radius is found to be roughly 2.5 times the virial radius and 1.7 − 3 times the splashback radius, in line with an approximately universal outer density profile, and the average enclosed density within the characteristic depletion radius is found to be roughly 29 times the mean matter density of the Universe in our sample. When binning haloes by both mass and a proxy for halo concentration, we do not detect a significant variation of the depletion radius with concentration, on which the simulation prediction is also sensitive to the choice of concentration proxy. We also confirm that the measured splashback radius varies with concentration differently from simulation predictions.

Abstract By simply modifying management decisions towards an environmentally friendly approach, organisations can minimise their negative operational impacts on the environment. A key question is whether a manager’s pro-environmental decision-making behaviour can be determined by their personal characteristics. Our study hypothesised that three core attributes (personal values, attitudes, and subjective norms) of a person can predict their future pro-environmental behavioural intention — the closest proxy of actual pro-environmental behaviour. Using the theoretical lenses of Value-Attitude-Behaviour theory (VAB) and Value-Belief-Norm theory (VBN), we examined the roles of three core attributes of future business leaders (MBA students) on their intention to behave pro-environmentally. The results of structural equation modelling indicate that future managers’ environmental values, attitudes, and subjective norms are positively associated with their intentions related to pro-environmental behaviour. Mediation test of the structural model further indicates that environmental attitudes mediate the link between personal values and intention; however, subjective norms does not. Our results imply that effective recruitment and selection mechanisms may incorporate these attributes to assist organisations in the identification of environmentally responsible business leaders. By hiring environmentally responsible managers, organisations will be able to better fulfil their commitment towards sustainability outcomes.

AbstractSubjective refraction is the gold-standard for prescribing refractive correction, but its accuracy is limited by patient’s subjective judgment about their clarity of vision. We asked if an involuntary eye movement, optokinetic nystagmus (OKN), could serve as an objective measure of visual-clarity, specifically measuring the dependence of OKN—elicited by drifting spatial-frequency filtered noise—on mean spherical equivalent (MSE) refractive error. In Experiment 1 we quantified OKN score—a measure of consistency with stimulus-direction—for participants with different MSEs. Estimates of MSE based on OKN scores correlate well with estimates of MSE made using autorefraction (r = 0.878, p < 0.001, Bland–Altman analysis: mean difference of 0.00D (95% limits of agreement: − 0.85 to + 0.85D). In Experiment 2, we quantified the relationship between OKN gain (ratio of tracking eye-movement velocity to stimulus velocity) and MSEs (− 2.00, − 1.00, − 0.50, 0.00 and + 1.00D) induced with contact lenses for each participant. The mean difference between measures of MSE based on autorefraction or on OKN gain was + 0.05D (− 0.90 to + 1.01D), and the correlation of these measures across participants was r = 0.976, p < 0.001. Results indicate that MSE attenuates OKN gain so that OKN can be used as an objective proxy for patient response to select the best corrective lens.

Tribes and Politics in Yemen tells the story of the Houthi conflict in Sa’dah Province, Yemen, as seen through the eyes of the local tribes. The Houthi conflict, which erupted in 2004, is often defined through the lenses of either the Iranian-Saudi proxy war or the Sunni–Shia divide. Yet, as experienced by locals, the Houthi conflict is much more deeply rooted in the recent history of Sa’dah Province and northern Yemen. Its origins must be sought in the political, economic, social and sectarian transformations since the 1960s civil war and their repercussions on the local society, which is dominated by tribal norms. From the civil war to the Houthi conflict these transformations involve the same individuals, families and groups, and are driven by the same struggles over resources, prerogatives, and power. This book is based on years of anthropological fieldwork both on the ground and through digital anthropological approaches. It offers an intimate view of the local complexities of the Houthi conflict and its historical background. By doing so, it underscores the absolute imperative of understanding the highly local, personal, and non-ideological nature of internal conflict in Yemen.