bluuebunny/crossref_metadata_2025 huggingface dataset:
Joint Cloud Water Path and Rain Water Path Retrievals from ORACLES Observations
Authors: Dzambo Andrew M. , L'Ecuyer Tristan , Sinclair Kenneth , van Diedenhoven Bastiaan , Gupta Siddhant , McFarquhar Greg , O'Brien Joseph R. , Cairns Brian , Wasilewski Andrzej P. , Alexandrov Mikhail
Published: August 2020

Abstract. This study presents a new algorithm that combines W-band reflectivity measurements from the Airborne Precipitation Radar-3rd generation (APR-3), passive radiometric cloud optical depth and effective radius retrievals from the Research Scanning Polarimeter (RSP) to estimate total liquid water path in warm clouds and identify the contributions from cloud water path (CWP) and rainwater path (RWP). The resulting CWP estimates are primarily determined by the optical depth input, although reflectivity measurements contribute ~ 10–50 % of the uncertainty due to attenuation through the profile. Uncertainties in CWP estimates across all conditions are 25 % to 35 %, while RWP uncertainty estimates frequently exceed 100 %. Two thirds of all radar-detected clouds observed during the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) campaign that took place from 2016–2018 over the southeast Atlantic Ocean have CWP between 41 and 168 g m−2 and almost all CWPs (99 %) between 6 to 445 g m−2. RWP, by contrast, typically makes up a much smaller fraction of total liquid water path (LWP) with more than 70 % of raining clouds having less than 10 g m−2 of rainwater. In heavier warm rain (i.e. rain rate exceeding 40 mm h−1 or 1000 mm d−1), however, RWP is observed to exceed 2500 g m−2. CWP (RWP) is found to be approximately 30 g m−2 (7 g m−2) larger in unstable environments compared to stable environments. Surface precipitation is also more than twice as likely in unstable environments. Comparisons against in-situ cloud microphysical probe data spanning the range of thermodynamic stability and meteorological conditions encountered across the southeast Atlantic basin demonstrate that the combined APR-3 and RSP dataset enable a robust joint cloud-precipitation retrieval algorithm to support future ORACLES precipitation susceptibility and cloud–aerosol–precipitation interaction studies.
Changes in high-intensity precipitation on the northern Apennines (Italy) as revealed by multidisciplinary data over the last 9000 years
Authors: Segadelli Stefano , Grazzini Federico , Rossi Veronica , Aguzzi Margherita , Marvelli Silvia , Marchesini Marco , Chelli Alessandro , Francese Roberto , De Nardo Maria Teresa , Nanni Sandro
Published: August 2020

Abstract. Several record-breaking precipitation events have struck the
mountainous area of the Emilia–Romagna region (northern Apennines, Italy) over
the last 10 years. As a consequence, severe geomorphological processes such
as debris avalanches and debris flows, shallow landslides, and overbank
flooding have affected the territory, causing severe damage to human-made
structures. The unusual intensity of these phenomena prompted an
investigation into their frequency in the past, beyond instrumental time. In
the quest for an understanding of whether these phenomena are unprecedented in
the region, peat bog and lake deposits were analyzed to infer the frequency
of extreme precipitation events that may have occurred in the past. We
present the results of a dedicated field campaign performed in summer 2017
at Lake Moo in the northern Apennines, a 0.15 km2 peat bog located at
an altitude of 1130 m a.s.l. During the extreme precipitation event of 13–14
September 2015, several debris flows generated by small streams
affected the Lake Moo plain. In such a small drainage basin (<2 km2), high-density floods can be triggered only by high-intensity
precipitation events. The sedimentary succession (ca. 13 m thick) was
studied through the drilling of two cores and one trench. The sequence,
characterized by clusters of coarse-grained alluvial deposits interbedded
with organic-rich silty clays and peat layers, was analyzed by combining
sedimentological, pollen, microanthracological and pedological data with
radiocarbon dating (AMS 14C) in an innovative multidisciplinary
approach for this area. Original data acquired during the field campaign
were also correlated with other specific paleoclimatic proxies available in
the literature for the northern Apennines area. We discover that the
increase in extreme paleoflooding, associated with coarse-grained deposits
similar to the ones observed recently, correlates well with the warm phases
of the Holocene Thermal Maximum and with the ongoing warming trend observed
that started at the beginning of the last century.
Bipolar volcanic synchronization of abrupt climate change in Greenland and Antarctic ice cores during the last glacial period
Authors: Svensson Anders , Dahl-Jensen Dorthe , Steffensen Jørgen Peder , Blunier Thomas , Rasmussen Sune O. , Vinther Bo M. , Vallelonga Paul , Capron Emilie , Gkinis Vasileios , Cook Eliza , Kjær Helle Astrid , Muscheler Raimund , Kipfstuhl Sepp , Wilhelms Frank , Stocker Thomas F. , Fischer Hubertus , Adolphi Florian , Erhardt Tobias , Sigl Michael , Landais Amaelle , Parrenin Frédéric , Buizert Christo , McConnell Joseph R. , Severi Mirko , Mulvaney Robert , Bigler Matthias
Published: August 2020

Abstract. The last glacial period is characterized by a number of millennial climate
events that have been identified in both Greenland and Antarctic ice cores
and that are abrupt in Greenland climate records. The mechanisms governing
this climate variability remain a puzzle that requires a precise
synchronization of ice cores from the two hemispheres to be resolved.
Previously, Greenland and Antarctic ice cores have been synchronized
primarily via their common records of gas concentrations or isotopes from
the trapped air and via cosmogenic isotopes measured on the ice. In this
work, we apply ice core volcanic proxies and annual layer counting to
identify large volcanic eruptions that have left a signature in both
Greenland and Antarctica. Generally, no tephra is associated with those
eruptions in the ice cores, so the source of the eruptions cannot be
identified. Instead, we identify and match sequences of volcanic eruptions
with bipolar distribution of sulfate, i.e. unique patterns of volcanic
events separated by the same number of years at the two poles. Using this
approach, we pinpoint 82 large bipolar volcanic eruptions throughout the
second half of the last glacial period (12–60 ka). This
improved ice core synchronization is applied to determine the bipolar
phasing of abrupt climate change events at decadal-scale precision. In
response to Greenland abrupt climatic transitions, we find a response in the
Antarctic water isotope signals (δ18O and deuterium excess)
that is both more immediate and more abrupt than that found with previous
gas-based interpolar synchronizations, providing additional support for our
volcanic framework. On average, the Antarctic bipolar seesaw climate
response lags the midpoint of Greenland abrupt δ18O transitions
by 122±24 years. The time difference between Antarctic signals in
deuterium excess and δ18O, which likewise informs the time
needed to propagate the signal as described by the theory of the bipolar
seesaw but is less sensitive to synchronization errors, suggests an
Antarctic δ18O lag behind Greenland of 152±37 years.
These estimates are shorter than the 200 years suggested by earlier
gas-based synchronizations. As before, we find variations in the timing and
duration between the response at different sites and for different events
suggesting an interaction of oceanic and atmospheric teleconnection patterns
as well as internal climate variability.
The sensitivity of the ENSO to volcanic aerosol spatial distribution in the MPI large ensemble
Authors: Ward Benjamin , Pausata Francesco S. R. , Maher Nicola
Published: August 2020

Abstract. Using the Max Planck Institute Grand Ensemble (MPI-GE) with 200 members for the historical simulation (1850–2005), we investigate the impact of the spatial distribution of volcanic aerosols on the ENSO response. In particular, we select 3 eruptions (El Chichón, Agung and Pinatubo) in which the aerosol is respectively confined to the Northern Hemisphere, the Southern Hemisphere or equally distributed across the equator. Our results show that the ENSO anomalies start at the end of the year of the eruption and peak the following one. Especially, we found that when the aerosol is located in the Northern Hemisphere or is symmetrically distributed, El Niño-like anomalies develop while aerosol distribution confined to the Southern Hemisphere leads to a La Niña-like anomaly. Our results strongly point to the volcanically induced displacement of the ITCZ as the main mechanism that drives the ENSO response, while suggesting that the other mechanisms (the ocean dynamical thermostat, the cooling of tropical northern Africa or of the Maritime continent) commonly invoked to explain the post-eruption ENSO response appear not to be at play in our model.
Dataset of Georeferenced Dams in South America (DDSA)
Authors: Paredes-Beltran Bolivar Eduardo , Sordo-Ward Alvaro , Garrote Luis
Published: August 2020

Abstract. Dams and their reservoirs generate major impacts on society and the environment. In general, its relevance relies on facilitating the management of water resources for anthropogenic purposes, however, dams could also generate many potential adverse impacts related to safety, ecology or biodiversity. These factors, and the additional effects that climate change could cause in these infrastructures and their surrounding environment, highlight the importance of dams and the necessity for their continuous monitoring and study. There are several studies examining dams both at regional and global scale, however, those that include the South America region focus mainly on the most renowned basins (primarily the Amazon basin), most likely due to the lack of records on the rest of the basins of the region. For this reason, a consistent database of georeferenced dams located in South America is presented: Dataset of georeferenced dams in South America DDSA. It contains 1,010 entries of dams with a combined reservoir volume of 1,017 cubic kilometres and it is presented in form of a list describing a total of 24 attributes that include the dams name, characteristics, purposes and georeferenced location. Also, hydrological and additional information on the dam’s catchments is also included: catchment area, mean precipitation, mean near-surface temperature, mean potential evapotranspiration, mean runoff, population and equipped area for irrigation. Information was obtained from public records, governments records, existing international databases and from extensive internet research. Each register was validated individually and geolocated using public access online map browsers and then, hydrological and additional information was derived from a hydrological model computed using the Hydrosheds dataset. With this database, we expect to contribute the development of new research in this region. The database is publicly available in https://doi.org/10.5281/zenodo.3885280.
“Are we talking just a bit of water out of bank? Or is it Armageddon?” Front line perspectives on transitioning to probabilistic fluvial flood forecasts in England
Authors: Arnal Louise , Anspoks Liz , Manson Susan , Neumann Jessica , Norton Tim , Stephens Elisabeth , Wolfenden Louise , Cloke Hannah Louise
Published: August 2020

Abstract. By showing the uncertainty surrounding a prediction,
probabilistic forecasts can give an earlier indication of potential upcoming
floods, increasing the amount of time available to prepare. However, making
a decision based on probabilistic information is challenging. As part of the
UK-wide policy's move towards forecast-based flood risk management, the
Environment Agency (EA), responsible for managing risks of flooding in
England, is transitioning towards the use of probabilistic fluvial forecasts
for flood early warning. While science and decision-making are both
individually progressing, there is still a lack of an ideal framework for the incorporation of new and probabilistic science into decision-making practices,
and, respectively, the uptake of decision-makers' perspectives in the design
of scientific practice. To address this, interviews were carried out with EA
decision-makers (i.e. Duty Officers), key players in the EA's flood warning
decision-making process, to understand how they perceive this transition
might impact on their decision-making. The interviews highlight the complex
landscape in which EA Duty Officers operate and the breadth of factors that
inform their decisions, in addition to the forecast. Although EA Duty Officers already account for uncertainty and communicate their confidence in
the forecast they currently use, the interviews revealed a decision-making
process which is still very binary and linear to an extent, which appears at
odds with probabilistic forecasting. Based on the interview results, we make
recommendations to support a successful transition to probabilistic
forecasting for flood early warning in England. These recommendations include the new system's co-design together with Duty Officers, the preparation of clear guidelines on how probabilistic forecast should be
used for decision-making in practice, EA communication with all players in the decision-making chain (internal and external) that this transition
will become operational practice and the documentation of this transition to
help other institutes yet to face a similar challenge. We believe that this paper is of wide interest for a range of sectors at the
intersection between geoscience and society. A glossary of technical terms
is highlighted by asterisks in the text and included in Appendix A.
Why did it not work? Reflections on regulating Airbnb and the complexity and agency of platform capitalism
Authors: Smigiel Christian
Published: August 2020

Abstract. This article deals with one of the most controversial topics in urban
studies related to mobile capital and mobile people. At first glance this
seems to be contradictory since numbers of short-term rentals have decreased
dramatically due to the coronavirus (SARS-CoV-2) pandemic. However, this
paper is not about numbers and statistics. Instead it discusses structural
issues regarding governance and power relations which remain important
topics (especially) in times of crisis. It provides insights regarding the
following issues: firstly, it deconstructs different “myths” that still
surround short-term rentals and Airbnb and secondly, it delineates the
structural power of Airbnb as a new urban institution. This helps us to
understand some of the conflicts over Airbnb and the pitfalls with current
forms of regulation on the one side as well as showing the complexity and
agency of short-term rentals on the other.
Flash drought onset over the Contiguous United States: Sensitivity of inventories and trends to quantitative definitions
Authors: Osman Mahmoud , Zaitchik Benjamin F. , Badr Hamada S. , Christian Jordan I. , Tadesse Tsegaye , Otkin Jason A. , Anderson Martha C.
Published: August 2020

Abstract. The term flash drought is frequently invoked to describe droughts that develop rapidly over a relatively short timescale. Despite extensive and growing research on flash drought processes, predictability, and trends, there is still no standard quantitative definition that encompasses all flash drought characteristics and pathways. Instead, diverse definitions have been proposed, supporting wide-ranging studies of flash drought but creating the potential for confusion as to what the term means and how to characterize it. Use of different definitions might also lead to different conclusions regarding flash drought frequency, predictability, and trends under climate change. In this study, we compared five previously published definitions, a newly proposed definition, and an operational satellite-based drought monitoring product to clarify conceptual differences and to investigate the sensitivity of flash drought inventories and trends to the choice of definition. Our analyses indicate that the newly introduced Soil Moisture Volatility Index definition effectively captures flash drought onset in both humid and arid regions. Analyses also showed that estimates of flash drought frequency, spatial distribution, and seasonality vary across the contiguous U.S. depending upon which definition is used. Definitions differ in their representation of some of the largest and most widely studied flash droughts of recent years. Trend analysis indicates that definitions that include air temperature show significant increases in flash droughts over the past forty years, but few trends are evident for definitions based on other surface conditions or fluxes. These results indicate that flash drought is a composite term that includes several types of event, and that clarity in definition is critical when monitoring, forecasting, or projecting the drought phenomenon.
Soil moisture and streamflow deficit anomaly index: An approach to quantify drought hazards by combining deficit and anomaly
Authors: Popat Eklavyya , Döll Petra
Published: August 2020

Abstract. Drought is understood as both a lack of water (i.e., a deficit as compared to some requirement) and an anomaly in the condition of one or more components of the hydrological cycle. Most drought indices, however, only consider the anomaly aspect, i.e., how unusual the condition is. In this paper, we present two drought hazard indices that reflect both the deficit and anomaly aspects. The soil moisture deficit anomaly index, SMDAI, is based on the drought severity index, DSI, but is computed in a more straightforward way that does not require the definition of a mapping function. We propose a new indicator of drought hazard for water supply from rivers, the streamflow deficit anomaly index, QDAI, which takes into account the surface water demand of humans and freshwater biota. Both indices are computed and analyzed at the global scale, with a spatial resolution of roughly 50 km, for the period 1981–2010, using monthly time series of variables computed by the global water resources and the model WaterGAP2.2d. We found that the SMDAI and QDAI values are broadly similar to values of purely anomaly-based indices. However, the deficit anomaly indices provide more differentiated, spatial and temporal patterns that help to distinguish the degree of the actual drought hazard to vegetation health or the water supply. QDAI can be made relevant for stakeholders with different perceptions about the importance of ecosystem protection, by adopting the approach for computing the amount of water that is required to remain in the river for the well-being of the river ecosystem. Both deficit anomaly indices are well suited for inclusion in local or global drought risk studies.
Experimental evidence that viscous shear zones generate periodic
pore sheets that focus mass transport
Authors: Gilgannon James , Waldvogel Marius , Poulet Thomas , Fusseis Florian , Berger Alfons , Barnhoorn Auke , Herwegh Marco
Published: August 2020

Abstract. In experiments designed to understand deep shear zones, we show that periodic porous sheets emerge spontaneously during viscous creep, forming a hydro-mechanical anisotropy that influences mass transfer. These findings challenge the current paradigm of viscosity in solid rocks. In particular, they showcase how shear zones may actively focus mass transport and highlight the possibility that viscous rocks could locally transition from flow to fracture. Our work demonstrates that viscosity in solids is not directly comparable to viscosity in fluids and this is consequential for a range of important solid Earth topics, like slow earthquakes, the flow of glacial ice and the tectonics of exoplanets.
Atmospheric extremes triggered the biggest calving event in more than 50 years at the Amery Ice shelf in September 2019
Authors: Francis Diana , Mattingly Kyle S. , Lhermitte Stef , Temimi Marouane , Heil Petra
Published: August 2020

Abstract. Ice shelf instability is one of the main sources of uncertainty in Antarctica's contribution to future sea level rise. Calving events play crucial role in ice shelf weakening but remain unpredictable and their governing processes are still poorly understood. In this study, we analyze the unexpected September 2019 calving event from the Amery Ice Shelf, the largest since 1963 and which occurred almost a decade earlier than expected, to better understand the role of the atmosphere in calving. We find that atmospheric extremes provided a deterministic role in this event. The calving was triggered by the occurrence of a series of anomalously-deep and stationary explosive twin polar cyclones over the Cooperation and Davis Seas which generated strong offshore winds leading to increased sea ice removal, fracture amplification along the pre-existing rift, and ultimately calving of the massive iceberg. The observed record-anomalous atmospheric conditions were promoted by blocking ridges and Antarctic-wide anomalous poleward transport of heat and moisture. Blocking highs helped in (i) directing moist and warm air masses towards the ice shelf and in (ii) maintaining stationary the observed extreme cyclones at the front of the ice shelf for several days. Accumulation of cold air over the ice sheet, due to the blocking highs, led to the formation of an intense cold-high pressure over the ice sheet, which helped fuel sustained anomalously-deep cyclones via increased baroclinicity. Our results stress the importance of atmospheric extremes in ice shelf instability and the need to be accounted for when considering Antarctic ice shelf variability and contribution to sea level, especially given that more of these extremes are predicted under a warmer climate.
The North Pacific Storm-Track Suppression Explained From a Cyclone Life-Cycle Perspective
Authors: Schemm Sebastian , Wernli Heini , Binder Hanin
Published: August 2020

Abstract. Surface cyclones that feed the part of the North Pacific storm track that experience a midwinter suppression originate from three regions: the East China Sea (~ 30º N), the Kuroshio extension (~ 35º N), and downstream of Kamchatka (~ 53º N). In terms of cyclone numbers, Kuroshio (45 %) and Kamchatka (40 %) cyclones dominate in the region where eddy kinetic energy is suppressed, while the relevance of East China Sea cyclones increases from winter (15 %) to spring (20 %). The equatorward movement during midwinter of the baroclinicity and the associated upper-level jet influences cyclones from the three genesis regions in different ways. In January, Kamchatka cyclones are less numerous, less intense and their lifetime shortens; broadly consistent with the reduced baroclinicity in which they grow. The opposite is found for East China Sea cyclones, which in winter live longer, are more intense, and experience more frequently explosive deepening. The fraction of explosive East China Sea cyclones is particularly high in January when they benefit from the increased baroclinicity in their environment. Again, a different and more complex behavior is found for Kuroshio cyclones. In midwinter, their number increases, but their lifetime decreases; on average they reach higher intensity, in terms of minimum sea-level pressure, but the fraction of explosively deepening cyclones reduces and the latitude where maximum growth occurs shifts equatorward. Therefore, the life cycle of Kuroshio cyclones seems to be accelerated in midwinter with a stronger and earlier but also shorter deepening phase followed by an earlier decay. Once they reach the latitude where eddy kinetic energy is suppressed in midwinter, their baroclinic conversion efficiency is strongly reduced. Together, this detailed cyclone life-cycle analysis reveals that the North Pacific storm-track suppression in midwinter is related to fewer and weaker Kamchatka cyclones and to more equatorward intensifying and then more rapidly decaying Kuroshio cyclones. The less numerous cyclone branch from the East China Sea partially opposes the midwinter suppression.
Oceanic origins for wintertime Euro-Atlantic blocking
Authors: Yamamoto Ayako , Nonaka Masami , Martineau Patrick , Yamazaki Akira , Kwon Young-Oh , Nakamura Hisashi , Taguchi Bunmei
Published: August 2020

Abstract. Although conventionally attributed to dry dynamics, increasing evidence points to a key role of moist dynamics in the formation and maintenance of blocking events. The source of moisture crucial for these processes, however, remains elusive. In this study, we identify the moisture sources responsible for latent heating associated with the wintertime Euro-Atlantic blocking events detected over 31 years (1979–2010). To this end, we track atmospheric particles backward in time from the blocking centres for a period of 10 days, using an offline Lagrangian dispersion model applied to an atmospheric reanalysis data. The analysis reveals that 36–55 % of particles gain a massive amount of heat and moisture from the ocean over the course of 10 days. Via large-scale ascent, these moist particles transport low potential vorticity (PV) air of low-altitude, low-latitude origins to the upper troposphere where the amplitude of blocking is the most prominent, consistent with the previous studies. PV of these moist particles remains significantly lower compared to their dry counterparts throughout the course of 10 days, preferentially constituting blocking cores. Further analysis reveals that approximately two-thirds of the moist particles source their moisture locally from the Atlantic, while the remaining one-third from the Pacific. The Gulf Stream and Kuroshio and their extensions, as well as the eastern Pacific northeast of Hawaii, not only provide heat and moisture to the particles but also act as springboards for their large-scale, cross-isentropic ascent. While the particles of the Atlantic origin swiftly ascend just before their arrival at the blocking, those of the Pacific origin ascend additional few days earlier, after which they carry low PV in the same manner as dry particles. Thus, our study reveals that what may appear to be a blocking maintenance mechanism governed by dry dynamics alone can, in fact, be of moist origin.
Supply Chain Integration Barriers to Port-Centric Logistics—An Emerging Economy Perspective
Authors: Venkatesh V.G. , Zhang Abraham , Deakins Eric , Mani Venkatesh , Shi Yangyan
Published: August 2020

Despite the growing interest in supply chain integration and port performance in the maritime literature, there is a lack of detailed studies into the barriers to integration in port-centric logistics. This study explores the barriers to port-centric supply chain integration from an emerging economy and multistakeholder perspective by using the DEMATEL (Decision Making-Trial and Evaluation Laboratory) analysis technique. The findings indicate that institutional requirements, lack of awareness by stakeholders, and port-centric supply chain integration all significantly impact supply chain projects that have been designed to offer maximum value to customers at a low cost. Other crucial barriers include the absence of benchmarking standards and lack of an innovation culture. The policy and managerial implications are explained.
Robust Optimization Model of Feeder Lines Routing Based on the Hub Port
Authors: Huang Xiaoling , Chen Huanping , Liu Lufeng , Chen Jihong
Published: August 2020

This article determines one reasonable feeder-line routing for a containership fleet performing pickup and deliveries between the hub ports and spoke ports. It first analyzes the relationship between the hub port and feeder lines and then investigates how to design robust feeder lines routing. A robust optimization model with pickup, deliveries, and time deadlines is built. Improved genetic algorithms are used to solve the model. Results show that the robust optimization model can improve the robustness of the feeder lines routing and reduce the investment risk caused by the uncertainty in the feeder network design.
Code-switching Versus Target-language-only for English as a Foreign Language: Saudi Students’ Perceptions
Authors: Tale‘ Mazeegha A. Al , Alqahtani Faten A.
Published: August 2020

Selecting the medium of instruction to teach English as a Foreign Language (EFL) has been a controversial issue for several years. This article explores the impact of code-switching (CS) versus target-language-only (TL-only) teaching strategies on the learning and affective sustenance of EFL reading comprehension beginner students based on their perceptions. It also investigates whether there is a significant difference between the participants’ perceptions of these two teaching strategies’ possible impact on their learning and affective sustenance. Fifty-two female Saudi college students participated in the study. A questionnaire and follow-up interviews were used to collect the data. The results indicate that the participants had positive perceptions about the impact of CS on their learning and affective sustenance in the EFL reading classes as opposed to negative perceptions about TL-only instruction. The results also show that there is a significant difference between their perceptions of TL-only instruction and CS, indicating that they prefer CS to TL-only instruction in their EFL reading classes. We recommend that reading comprehension teachers for beginners utilize CS as a facilitating instructional strategy for EFL beginners to give them affective support and make the input more comprehensible.
The Minimum Numbers for Certain Positive Operators
Authors: Suen Ching-Yun
Published: August 2020

In this paper we give upper and lower bounds of the infimum of k  such that kI+2ReT⊗Sm  is positive, where Sm  is the m×m  matrix whose entries are all 0’s except on the superdiagonal where they are all 1’s and T∈BH  for some Hilbert space H.

When T  is self-adjoint, we have the minimum of k.

When m=3  and T∈B(H)  , we obtain the minimum of k  and an inequality

Involving the numerical radius w(T) .
De veranderende taak van bestuurders in het tijdperk van AI
Authors: van de Ven S.W.
Published: August 2020

De veranderende taak van bestuurders in het tijdperk van AI

Het gebruik van artificial intelligence (AI) door vennootschappen zal de komende jaren een vlucht nemen, met ingrijpende veranderingen voor de bestuurstaak tot gevolg. Dit artikel bespreekt de noodzaak voor bestuurders tot het voeren van deugdelijk AI-risicobeheer alsmede de manier waarop deze vorm van risicobeheer de maatstaf voor bestuurdersaansprakelijkheid dient in te kleuren.
Rechtsmaatregelen tegen misbruik van abstracte bankgaranties (I)
Authors: Russcher P.C.
Published: August 2020

Rechtsmaatregelen tegen misbruik van abstracte bankgaranties (I)

Het gebeurt regelmatig dat de opdrachtgever van een bankgarantie probeert uitbetaling door de bank te beletten, maar deze pogingen zijn zelden succesvol. Naar aanleiding van een aantal recente uitspraken, waarin de opdrachtgever wél succes had, wordt in deze – in twee delen te verschijnen – bijdrage aan de hand van een systematische behandeling van rechtspraak en literatuur ingegaan op rechtsmaatregelen die de opdrachtgever kan nemen.
Piri-Muridi in the Twin Cities of Islamabad and Rawalpindi, Pakistan
Authors: Hansen David
Published: August 2020

Sufism, piri-muridi, in Pakistan is an overlooked aspect of Muslim religious experience. This article sheds light on how respondents of the Twin Cities of Islamabad and Rawalpindi, Pakistan, relate to this overlooked aspect, and tries to situate changes to piri-muridi in a historical context. As this article finds, being orthodox does not necessarily hinder adherence to piri-muridi. Rather, people of all sects, and even non-Muslims, regularly attend ‘urs, keep a relationship with a pir, or visit the shrines on occasions – as ways of exhausting all possibilities to find comfort, seek spirituality, or solve practical problems in their lives. This aspect, then, breaks down the apparent divide between the orthodox and the traditional in the sense that many people pick bits and pieces and make those pieces into their own practiced form of Islam. Yet, piri-muridi in the Twin Cities is experiencing a purification process where its opponents try their best to discredit it as ‘un-Islamic’, and its adherents are often critical of certain practices and rituals but still obey it.
Book Reviews Acta Orientalia 40
Authors: Orientalia Acta
Published: August 2020

Book reviews in Acta Orientalia 40
CARTOGRAFIA SOCIAL DA ILHA DE COTIJUBA – BELÉM/PA
Authors: Vicente Leticia Ribeiro , Cardoso Ana Cláudia  Duarte , Oliveira Rafaela Carolina Bulhões de
Published: August 2020

O caso da ilha de Cotijuba, município de Belém (PA), é apresentado no texto a partir da visão de movimentos sociais locais sobre as potencialidades e fragilidades da ilha, apontadas em cartografia social, entrevistas e vivências. Observa-se que ações de iniciativa popular apoiam o modo de vida local em contexto de isolamento e controle público da terra, mas tem limitações que só poderão ser devidamente superadas com políticas públicas adequadas e perspectiva de longo prazo, que reconheçam as múltiplas faces e funções da ilha, sem reduzi-la à condição de periferia metropolitana.
Heroism in Victorian Periodicals 1850–1900
Authors: Hadamitzky Christiane
Published: August 2020

Nineteenth century Britain was an age of rapid technological, political and societal change. This was also reflected in the media: Industrially-produced print media opened a mass market with publications for almost any (niche-) interest one could think of. The societal changes also resulted in a growing need for orientation which in many publications was answered using the semantics of the heroic. As guiding figures, heroes were supposed to offer role models for a variety different readerships. By analysing Chambers’s Journal, Fraser’s Magazine and Leisure Hour, this study analyses different conceptions of the heroic on the Victorian print market and shows how the heroic was used for different didactic, social and political purposes in addressing different readerships within the context of changing power structures.
Critical Care Pharmacist Using Free Drug-Interaction Checker Mobile Apps Can Ensure Medication Safety in Critically Ill Patients
Authors: Hasan Md Jahidul , Rabbani Raihan , Bachar Sitesh C
Published: August 2020

Background: Critical care pharmacists (CCPs) have a key role in ensuring medication safety by screening drug-drug interactions (DIs) in polypharmacy prescriptions, mostly in critically ill patients. The drug-interaction checker mobile apps (DICMA) are freely available for smartphones. Objectives: The current study aimed to assess the utilization of smartphone-based free mobile apps by CCPs for ensuring drug-drug interaction-free polypharmacy prescriptions in critically ill patients. Methods: This observational study was conducted in an intensive care unit. Critical care pharmacists (CCPs) checked the medications of polypharmacy prescriptions to detect DIs or potential drug-drug interactions (PDIs) using free DICMA installed on their smartphones. DIs/PDIs were sent to physicians as suggestions, and the prescriptions were modified accordingly. Results: CCPs screened 2,967 prescriptions, where 11,128 and 3,932 DIs and PDIs were identified, respectively. Prescriptions with 6 to 10 medications and prescription with more than 10 medications, on average, had 3.28 and 7.53 DIs, respectively, and 1.42 and 4.7 PDIs, respectively. Physicians accepted 95.85% (n = 3,932) of PDI suggestions from CCPs and modified prescriptions, accordingly. CCPs reported a satisfaction level of 4 (on a scale of 5) concerning the use of free DICMA. Conclusions: Drug-drug interactions-free polypharmacy prescriptions can ensure medication safety in patients. CCPs are professionally responsible for this task, but resource-limited setups do not provide them scopes to accomplish this task efficiently. In this study, CCPs ensured medication safety in the prescriptions of critically ill patients efficiently using free DICMA installed on their smartphones.
Behavioral Objeaives and Flexible Grouping in Seventh Grade Mathematics
Authors: Bierden James E.
Published: August 2020

The purpose of this study was to explore and develop a form of classroom management to aid in the provision for individual differences among students in seventh-grade mathematics. The 2 major variations from standard classroom procedures were (1) the classroom use of detailed behavioral objectives related to the content of the course, and (2) a form of classroom management using a combination of whole-class instruction and flexible intra-class grouping based on achievement of the objectives. The evaluation of student performance suggests aspects of these variations have potential for improving mathematics instruction.
Explicit Heuristic Training as a Variable in Problem-Solving Performance
Authors: Schoenfeld Alan H.
Published: August 2020

This experiment examined the impact that explicit instruction in heuristic strategies, above and beyond problem-solving experience, has on students' problem-solving performance. Two groups of students received training in problem solving, spent the same amount of time working on the same problems, and saw identical problem solutions. But half the students were given a list of five problem-solving strategies and were shown explicitly how the strategies were used. The heuristics group significantly outperformed the other students on posttest problems that were similar to, but not isomorphic to, those used in the problem sets. This lends credence to the idea that explicit instruction in heuristics makes a difference--an idea further supported by the transcripts of students solving the problems out loud.
Student Perceptions of Relatedness among Mathematical Verbal Problems
Authors: Silver Edward A.
Published: August 2020

Two studies investigated the relationship between students' perceptions of mathematical problem relatedness and their performance on tests of verbal and mathematical ability. A total of 156 eighth-grade students partitioned collections of mathematical verbal problems into disjoint subsets whose problems they judged to be mathematically related. The extent to which a person sorted problems on the basis of mathematical structure was significantly related to the individual's problem-solving ability as well as other mathematical and verbal abilities. Furthermore, partial correlations analysis indicated that the relationship remained significant even when the effects of general ability variables such as IQ were controlled.
Incorrect Procedures Used by Primary Grade Pupils in Solving Open Addition and Subtraction Sentences
Authors: Lindvall C. Mauritz , Ibarra Cheryl Gibbons
Published: August 2020

A number of research studies have been concerned with the types of errors that primary grade pupils make in attempting to solve open addition and subtraction sentences. This investigation attempted to offer some possible explanations for the use of certain incorrect procedures. Interview testing of 101 primary grade pupils was done with a sample from five different types of communities. In general, the findings indicate that most pupils' errors are associated with an incorrect, and inconsistent, reading of the number sentences. This difficulty, in turn, appears to be related to a need for pupils to learn to read such sentences both as descriptions of an operation and as statements of an equivalence relationship.
Effectiveness of Systematic Instruction on Attitudes and Computational Estimation Skills of Preservice Elementary Teachers
Authors: Bestgen Barbara J. , Reys Robert E. , Rybolt James F. , Wyatt J. Wendell
Published: August 2020

This 12-week study examined attitudes and performance of 187 preservice elementary teachers on computational estimation and evaluated practice with and without instruction on specific mental estimation strategies. Three groups--a control group, a group receiving weekly practice on computational estimation, and a group receiving weekly practice and instruction in estimation techniques--were formed. Analysis showed significant differences (p<.01) on performance in estimation in favor of the groups receiving regular practice. No significant difference was found between groups receiving only practice and those receiving practice and instruction. The later group, however, did display a greater understanding of the processes involved in doing estimation.
Student Perception of Teacher Clarity in Mathematics
Authors: Smith Lyle R. , Land Michael L.
Published: August 2020

College students (n=160) were randomly assigned to eight groups defined by the possible combinations of teacher-vagueness conditions (vagueness vs. no vagueness), teacher-mazes conditions (mazes vs. no mazes), and additional-unexplained-content conditions (extra content vs. no extra content). Each group was presented a lesson concerning mathematical concepts. After the lesson, each group was tested on comprehension of the concepts, and then the students evaluated the lesson presentation. The groups whose lessons contained no teacher mazes (no teacher vagueness) performed better on the test than the groups whose lessons contained teacher mazes (teacher vagueness).
The Evaluation of an Application-Oriented First-Year Algebra Program
Authors: Swafford Jane O. , Kepner Henry S.
Published: August 2020

Experimental first-year algebra materials, Algebra Through Applications, were developed by Zalman Usiskin of the University of Chicago under a grant from NSF. This study was a field evaluation of the materials conducted in 20 schools across the country. The effectiveness of the materials was evaluated in terms of achievement, attitude, transfer to consumer problem solving, readability, and implementability. Overall, it was found that the experimental materials could be used effectively in a variety of school settings. Recommendations are made concerning the use and implementation of the materials.
Increasing Women's Participation in Mathematics: An Intervention Study
Authors: Fennema Elizabeth , Daniels Pedro Joan , Wolleat Patricia L. , Devaney Becker Ann
Published: August 2020

This study reports the evaluation of an educational intervention (Multiplying Options and Subtracting Bias) designed to increase the election of mathematics courses by high school females. A pretest/posttest control group design was used. Females in the experimental group, significantly more than females in the control group, increased their knowledge about sex-related differences in mathematics, indicated that they were going to study more mathematics both during and after high school, and actually enrolled in more mathematics courses. Change in the perception of the usefulness of mathematics for their future lives was significantly related to change in plans for the study of mathematics. The effect of the intervention on male peers, mathematics teachers, and counselors is also reported.
Differential Treatment of Females and Males in Mathematics Classes
Authors: Rossi Becker Joanne
Published: August 2020

This observational study of 10 high school geometry teachers combined the collection of quantitative and qualitative data using participant observation techniques to determine if there was differential treatment of male and female students. Categorical data gathered by use of the Brophy-Good Teacher-Child Dyadic Interaction System were analyzed by inferential and descriptive statistics. Ethnographic data were analyzed using anthropological field research techniques. Combined data showed a distinct trend for disproportionate teacher contacts, in both quantity and quality, with male students. It is hypothesized, based on observed behavior and interviews, that the sites displayed a type of self-fulfilling prophecy, with differential expectations by teachers for behavior of students of each sex causing differential treatment of students, which, in turn, contributed to differences in student behavior.
Conservation of Equation and Function under Transformations of Variable
Authors: Wagner Sigrid
Published: August 2020

Tasks that test conservation of equation and function under transformations of variable illustrate an extension of Piaget's conservation methodology to relational concepts. Less than half of the 30 students interviewed in grades 5-12 gave conserving responses to any one of the four tasks. Mathematical background was a significant factor in performance. Students who did not conserve harbored two misconceptions: (a) that changing a variable symbol implies changing the referent and (b) the linear ordering of the alphabet corresponds to the linear ordering of numbers.
A Forum for Researchers: Women and Mathematics: Does Research Matter?
Authors: Fennema Elizabeth
Published: August 2020

On Monday, March 23, I was in a somewhat unusual and comfortable situation for a university professor. (Perhaps one should really substitute the word lazy for comfortable.) I had written a chapter for the 1982 NCTM Yearbook on the middle school, and it could serve as my NCTM speech at St. Louis. True, I had not said anything very new, innovative, or controversial; but after all, this was the third year in a row that I had talked about sex-related differences at NCTM, so no one could expect me to have much new information or insight. Then, as I was reading the newspaper and having a leisurely cup of tea before going to school, I read the following: “ Due to evolutionary factors, males are also better at doing math problems … ” (Wisconsin State Journal, March 23, 198 1).
Measures of Problem-Solving Performance and of Problem-Solving Instruction
Authors: Schoenfeld Alan H.
Published: August 2020

This article presents and discusses three paper-and-pencil tests of students' performance on nonroutine mathematics problems at the college level. These tests assess the following: 1. the frequency with which students apply various problem-solving heuristics, and how far and with what success they pursue them; 2. students' subjective assessments of their own problem-solving behavior; and 3. transfer of heuristic behavior on problems related in various degrees to ones that students have studied. These measures were used to assess students' performance before and after a month-long intensive problem-solving course. They provide evidence that such a course can produce strong changes in students' problem-solving behavior.
Skill in Estimation Problems of Extent and Numerosity
Authors: Siegel Alexander W. , Goldsmith Lynn T. , Madson Camilla R.
Published: August 2020

A preliminary model of the estimation process was proposed for problems involving numerosity and extent. The model distinguished two basic strategies: benchmark estimation and decomposition/recomposition estimation. Children in Grades 2 through 8 (n=140) and adults (nn=10) solved a series of estimation problems. Accuracy and reasonableness of solution were examined. Age-related differences were found, and analyses indicated only a loose relationship between accurate estimates and appropriate solution strategies. In light of these data, a revised model is presented and different dimensions of estimation problems indicated by the model are discussed.
Research on Mathematics Education Reported in 1981
Authors: Suydam Marilyn N.
Published: August 2020

This is the 12th annual listing of research on mathematics education to appear in JRME. It is organized alphabetically by author(s) within three categories (research summaries, journal-published reports, and dissertation abstracts). Grade or age is indicated for each reference, and an index of general topics is included to help readers locate studies of particular interest:
The Position of the Unknown Set and Children's Solutions of Verbal Arithmetic Problems
Authors: Hiebert James
Published: August 2020

This study examines the position of the unknown set and children's representation and solution processes for verbal addition and subtraction problems. Forty-seven first-grade children were given three joining problems and three separating problems in an individual interview. Each joining and separating problem had a different quantity as the unknown. Small blocks were available for children to use to model the problems. Results indicated that the position of the unknown had a profound effect on children's modeling behavior, which in turn affected the choice of the solution process and the relative difficulty of the problem.