463 research outputs found
Generalized Slater-Pauling rule for the inverse Heusler compounds
We present extensive first-principles calculations on the inverse
full-Heusler compounds having the chemical formula XYZ where (X = Sc, Ti,
V, Cr or Mn), (Z = Al, Si or As) and the Y ranges from Ti to Zn. Several of
these alloys are identified to be half-metallic magnets. We show that the
appearance of half-metallicity is associated in all cases to a Slater-Pauling
behavior of the total spin-magnetic moment. There are three different variants
of this rule for the inverse Heusler alloys depending on the chemical type of
the constituent transition-metal atoms. Simple arguments regarding the
hybridization of the d-orbitals of neighboring atoms can explain these rules.
We expect our results to trigger further experimental interest on this type of
half-metallic Heusler compounds.Comment: 5 pages, 3 figures, 1 tabl
Optimizing the Access to Healthcare Services in Dense Refugee Hosting Urban Areas: A Case for Istanbul
With over 3.5 million refugees, Turkey continues to host the world's largest
refugee population. This introduced several challenges in many areas including
access to healthcare system. Refugees have legal rights to free healthcare
services in Turkey's public hospitals. With the aim of increasing healthcare
access for refugees, we looked at where the lack of infrastructure is felt the
most. Our study attempts to address these problems by assessing whether Migrant
Health Centers' locations are optimal. The aim of this study is to improve
refugees' access to healthcare services in Istanbul by improving the locations
of health facilities available to them. We used call data records provided by
Turk Telekom.Comment: version to submit for D4R competitio
How does a biopsy of endoscopically normal terminal ileum contribute to the diagnosis? Which patients should undergo biopsy?
Background: Terminal ileum endoscopy and biopsy are the diagnostic tools of diseases attacking the ileum. However, abnormal histological findings can be found in endoscopically normal terminal ileum.Objective: This study was performed to evaluate the histopathological results of biopsies from endoscopically normal terminal ileum in order to determine pre-procedure clinical and laboratory factors predicting abnormal histopathological results, if any.Methods: A total of 297 patients who underwent colonoscopy and terminal ileum biopsy and had normal terminal ileum or a few aphthous ulcers in the terminal ileum together with completely normal colon mucosa were included in the study. The patients were grouped into two arms as normal cases and cases with aphthous ulcers. Histopathological and pre-procedural laboratory results of patients were analyzed according to their indications.Results: The terminal ileum was endoscopically normal in 200 patients, and 97 patients had aphthous ulcers. Chronic ileitis rate was present in 5.5% of those with endoscopically normal terminal ileum and in 39.2% of the patients with aphthous ulcers. In both groups, the highest rate of chronic ileitis was detected in the patients with known inflammatory bowel disease (IBD) (15.4 and 50%, respectively), anemia (9.5 and 43.5%, respectively), and in the patients having chronic diarrhea together with abdominal pain (7.7 and 44.8%, respectively). We found that the sensitivity of mean platelet volume for predicting chronic ileitis was 87% and the specificity was 45% at a cut-off value lower than 9.35 fl.Conclusion: In anemia indication or chronic diarrhea together with abdominal pain, the frequency of aphthous ulcers detected by ileoscopy and the frequency of chronic ileitis detected histopathologically despite a normal-appearing ileum were elevated.Keywords: Terminal ileum; ileoscopy; chronic ileitis; inflammatory bowel diseas
Renal hyperfiltration defined by high estimated glomerular filtration rate:A risk factor for cardiovascular disease and mortality
Renal hyperfiltration, defined as an increased glomerular filtration rate above normal values, is associated with early phases of kidney disease in the setting of various conditions such as obesity and diabetes. Although it is recognized that glomerular hyperfiltration, that is, increased filtration per nephron unit (usually studied at low glomerular filtration levels and often referred to as single nephron hyperfiltration), is a risk factor for the progression of chronic kidney disease, the implications of having renal hyperfiltration for cardiovascular disease and mortality risk are incompletely understood. Recent evidence from diverse populations, including healthy individuals and patients with diabetes or established cardiovascular disease, suggests that renal hyperfiltration is associated with a higher risk of cardiovascular disease and all-cause mortality. In this review, we critically summarize the existing studies, discuss possible mechanisms, and describe the remaining gaps in our knowledge regarding the association of renal hyperfiltration with cardiovascular disease and mortality risk
Congenital anomalies in low- and middle-income countries: the unborn child of global surgery.
Surgically correctable congenital anomalies cause a substantial burden of global morbidity and mortality. These anomalies disproportionately affect children in low- and middle-income countries (LMICs) due to sociocultural, economic, and structural factors that limit the accessibility and quality of pediatric surgery. While data from LMICs are sparse, available evidence suggests that the true human and financial cost of congenital anomalies is grossly underestimated and that pediatric surgery is a cost-effective intervention with the potential to avert significant premature mortality and lifelong disability
Global Food Security Support Analysis Data (GFSAD) at Nominal 1 km (GCAD) Derived from Remote Sensing in Support of Food Security in the Twenty-First Century: Current Achievements and Future Possibilities
The precise estimation of the global agricultural cropland—
extents, areas, geographic locations, crop types, cropping
intensities, and their watering methods (irrigated or rain-fed;
type of irrigation)—provides a critical scientific basis for the
development of water and food security policies (Thenkabail
et al., 2010, 2011, 2012). By year 2100, the global human population
is expected to grow to 10.4 billion under median fertility
variants or higher under constant or higher fertility
variants (Table 6.1) with over three-quarters living in developing
countries and in regions that already lack the capacity
to produce enough food. With current agricultural practices,
the increased demand for food and nutrition would require
about 2 billion hectares of additional cropland, about twice
the equivalent to the land area of the United States, and lead to
significant increases in greenhouse gas productions associated
with agricultural practices and activities (Tillman et al., 2011).
For example, during 1960–2010, world population more than
doubled from 3 to 7 billion. The nutritional demand of the
population also grew swiftly during this period from an average
of about 2000 calories per day per person in 1960 to nearly
3000 calories per day per person in 2010. The food demand of
increased population along with increased nutritional demand
during this period was met by the “green revolution,” which
more than tripled the food production, even though croplands
decreased from about 0.43 ha per capita to 0.26 ha per capita
(FAO, 2009). The increase in food production during the
green revolution was the result of factors such as: (1) expansion
of irrigated croplands, which had increased in 2000 from
130 Mha in the 1960s to between 278 Mha (Siebert et al., 2006)
and 467 Mha (Thenkabail et al., 2009a,b,c), with the larger estimate
due to consideration of cropping intensity; (2) increase in
yield and per capita production of food (e.g., cereal production
from 280 to 380 kg/person and meat from 22 to 34 kg/person
(McIntyre, 2008); (3) new cultivar types (e.g., hybrid varieties
of wheat and rice, biotechnology); and (4) modern agronomic
and crop management practices (e.g., fertilizers, herbicide,
pesticide applications)..
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