Computing Graph Roots Without Short Cycles

Graph G is the square of graph H if two vertices x, y have an edge in G if and only if x, y are of distance at most two in H. Given H it is easy to compute its square H2, however Motwani and Sudan proved that it is NP-complete to determine if a given graph G is the square of some graph H (of girth 3). In this paper we consider the characterization and recognition problems of graphs that are squares of graphs of small girth, i.e. to determine if G = H2 for some graph H of small girth. The main results are the following. - There is a graph theoretical characterization for graphs that are squares of some graph of girth at least 7. A corollary is that if a graph G has a square root H of girth at least 7 then H is unique up to isomorphism. - There is a polynomial time algorithm to recognize if G = H2 for some graph H of girth at least 6. - It is NP-complete to recognize if G = H2 for some graph H of girth 4. These results almost provide a dichotomy theorem for the complexity of the recognition problem in terms of girth of the square roots. The algorithmic and graph theoretical results generalize previous results on tree square roots, and provide polynomial time algorithms to compute a graph square root of small girth if it exists. Some open questions and conjectures will also be discussed

The Relationship Between Number Of Toys, Infant Distractibility, And Mothers\u27 Teaching Utterances

The purpose of this study is to investigate the relationship among the number of toys in an infant’s play environment, infant’s distractibility, and how often a mother teaches her infant during a play session. This study takes samples from videotapes of 12-month old children playing with their mothers during a 5 minute free-play situation. Twenty-two mother and infant pairs were selected for this study based on their previous participation in a language study. The measures used in this study were: (1) the number of maternal teaching utterances to her infant; (2) the total number of utterances that mother used during the play session with the child; (3) the number of toys that were visible in the room; (4) the factors that distracted the infant during the play session; and (5) the type of toy the infant choses to engage with

HIGH ARSENIC CONCENTRATION IN GROUNDWATER RELATED TO SEDIMENTARY FACIES IN THE MEKONG RIVER DELTA, VIETNAM

Arsenic (As) contamination in groundwater has been recognized in the Mekong River Delta (MRD) since 2001, especially in Dong Thap and An Giang provinces. The investigations were carried out during 2008-2009 and from 2012 to present. The investigations of As distribution in groundwater and sediments were based upon the field, and laboratory analyses using field kit (Hironaka, 1998) and AOAC laboratory - Vietnamese standard 6626-2000 (Vilas). Results show that the As concentrations ranging from 15 to 1,650 µg/l is found in 520 private tubewells at depth between 15 and 90 m, while being rare or very low at depth between 200 and 300 m. High As content is usually found in 15-70m tubewells in which approximately 70 - 80% of tubewells having arsenic levels of 500µg/l are located at some areas in Dong Thap and An Giang provinces in the upper MRD plain. Bore core drilling records show a probable relationship between As concentration in groundwater and sedimentary facies in the MRD. The highest As content is found along the Mekong River valleys in the Late Pleistocene and Holocene aquifers. References Ahmed, K.M., et al., 2004. Arsenic enrichment in groundwater of the alluvial aquifers in Bangladesh: an overview, Applied Geochemistry, 19(2), 181-200. Nguyen. V.L., Ta. T.K.O., Tateishi. M., 2000. Late Holocene depositional environments and coastal evolution of the Mekong River Delta, Southern Vietnam. Journal of Asian Earth Sciences. 18(4), 427-439. Nguyen. V.L., Ta. T.K.O., and Nguyen. V.D., 2006. Some results from study on arsenic contamination in groundwater in the Mekong River Delta and solutions to prevent. VAST Workshop on Science and Technology in relation of practice. Ho Chi Minh City. 6 pp. (in Vietnamese with English abstract). Nguyen, V.L., Ta. T.K.O., and Nguyen. V.D., 2008: Groundwater arsenic contamination in the Mekong River Delta - its effect on environment and public health. Proceedings of Research on Science and Technology, HCMC Institute of Resources Geology, 47-53 (in Vietnamese with English abstract). Nguyen. V.L., Ta. T.K.O. and Nguyen. V.D., 2009: Recent situation of arsenic contamination in groundwater in Dong Thap Province, Mekong River Delta, Southern Vietnam. Technical report. 98 pp (in Vietnamese). Nguyen Van Lap, Ta Thi Kim Oanh, Saito, Y., 2010: Early Holocene initiation of the Mekong River Delta, Vietnam, and the response to Holocene sea-level changes detected from DT1 core analyses. Sedimentary Geology, 230, 146- 155. Polizzotto, M.L., Kocar B.D., Benner, S.G., Sampson, M. and Fendorf, S., 2008: Near-surface wetland sediments as a source of arsenic release to ground water in Asia. Nature  454, 505-508. Ta, T.K.O., Nguyen, V.L., Tateishi, M., Iwao, K., Saito, Y., 2002: Holocene delta evolution and sediment discharge of the Mekong River, southern Vietnam. Quaternary Science Reviews, 21, 1807-1819. Ta. T.K.O., Nguyen. V.L., Tateishi. M., Kobayashi. I., Saito. Y., 2005: Holocene delta evolution and depositional models of the Mekong River Delta, southern Vietnam. In L. Giosan and J.P. Bhattacharya. eds., River Deltas-Concepts, Models and Examples. SEPM special publication. 83. 453-466. Tamura T., Saito Y., Sieng, S., Ben, B., Kong, M., Choup, S., Tsukawaki, S., 2009. Initiation of the Mekong River delta at 8 ka: evidence from the sedimentary succession in the Cambodian lowlands. Quaternary Science Reviews 28, 327-344. Research Group for Applied Geology, 1999: Arsenic contamination of groundwater in Bangladesh, Tech. Rep., 90

Pathological complete response and survival of HER2-positive invasive breast cancer following docetaxel, carboplatin, and trastuzumab neoadjuvant therapy: a Vietnamese experience

Introduction. Neoadjuvant chemotherapy for HER2-positive breast cancer consists of a chemotherapy regimen plus trastuzumab with or without pertuzumab. The use of trastuzumab has been shown to improve pathological complete response (pCR), disease-free survival (DFS), and overall survival (OS). Purposes: To evaluate the efficacy and safety of neoadjuvant docetaxel, carboplatin, and trastuzumab (TCH) in the treatment of HER2-positive breast cancer in Vietnamese patients.  Material and methods. This retrospective study reviewed stage II–III HER2-positive breast cancer patients who received neoadjuvant docetaxel, carboplatin, and trastuzumab (TCH) at the Vietnamese National Cancer Hospital. The primary endpoint was the pCR rate which was defined as the absence of invasive tumor in the breast and axillary nodes (ypT0/is, ypN0). The secondary endpoints were DFS, OS, and toxicities.  Results. The complete and partial clinical response of 51 patients were 33.3% and 58.8%, respectively. The pCR rate was 41.2%; there was a significantly higher response in cT1-2 patients compared to cT3-4 ones (61.1% vs. 39.3%, p = 0.033). Three-year estimated DFS and OS rates were 81.3% and 93.0%, respectively. Treatment was generally well tolerated. Grade 3/4 neutropenia and anemia were uncommon (21.6% and 7.8%). No symptomatic cardiac dysfunction occurred.  Conclusions. Neoadjuvant TCH, non-anthracycline chemotherapy with single anti-HER2 regimen achieved high efficacy, with a good pCR rate and favorable tolerability in stage II or III HER2-positive breast cancer patients

Abandonment and rapid infilling of a tide-dominated distributary channel at 0.7 ka in the Mekong River Delta

The Ba Lai distributary channel of the Mekong River Delta was abandoned and infilled with sediment during the Late Holocene, providing a unique opportunity to investigate the sediment fill, timing and mechanisms of channel abandonment in tide-dominated deltaic systems. Based on analysis and age dating of four sediment cores, we show that the channel was active since 2.6 ka and was abandoned at 0.7 ka as marked by the abrupt disappearance of the sand fraction and increase in organic matter and sediment accumulation rate. We estimate that the channel might have been filled in a time range of 45–263 years after detachment from the deltaic network, with sediment accumulation rates of centimetres to decimetres per year, rapidly storing approximately 600 Mt of organic-rich mud. We suggest that the channel was abandoned due to a sediment buildup favoured by an increase in regional sediment supply to the delta. This study highlights that mechanisms for abandonment and infilling of tide-dominated deltaic channels do not entirely fit widely used models developed for fluvial-dominated environments. Their abandonment might be driven by autogenic factors related to the river-tidal and deltaic dynamics and favoured by allogenic factors (e.g., human impact and/or climate change).</jats:p

Thermochronology of mineral grains in the Red and Mekong Rivers, Vietnam: Provenance and exhumation implications for Southeast Asia

Sand samples from the mouths of the Red and Mekong Rivers were analyzed to determine the provenance and exhumation history of their source regions. U-Pb dating of detrital zircon grains shows that the main sources comprise crust formed within the Yangtze Craton and during the Triassic Indosinian Orogeny. Indosinian grains in the Mekong are younger (210-240 Ma) than those in the Red River (230-290 Ma), suggesting preferential erosion of the Qiangtang Block of Tibet into the Mekong. The Red River has a higher proportion of 700-800 Ma grains originally derived from the Yangtze Craton. 40Ar/ 39Ar dating of muscovite grains demonstrates that rocks cooled during the Indosinian Orogeny are dominant in both rivers, although the Mekong also shows a grain population cooling at 150-200 Ma that is not seen in the Red River and which is probably of original Qiangtang Block origin. Conversely, the Red River contains a significant mica population (350-500 Ma) eroded from the Yangtze Craton. High-grade metamorphic rocks exposed in the Cenozoic shear zones of southeast Tibet-Yunnan are minority sources to the rivers. However, apatite and zircon fission track ages show evidence for the dominant sources, especially in the Red River, only being exhumed through the shallowest 5-3 km of the crust since ̃25 Ma. The thermochronology data are consistent with erosion of recycled sediment from the inverted Simao and Chuxiong Basins, from gorges that incise the eastern flank of the plateau. Average Neogene exhumation rates are 104-191 m/Myr in the Red River basin, which is within error of the 178 ± 35 m/Myr estimated from Pleistocene sediment volumes. Sparse fission track data from the Mekong River support the Ar-Ar and U-Pb ages in favoring tectonically driven rock uplift and gorge incision as the dominant control on erosion, with precipitation being an important secondary influence. © 2006 by the American Geophysical Union

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Optimizing Conditions for The Production Process of Cashew Apple Juice (Anacardium Occidentale L.) From Binh Phuoc (Viet Nam) Using Response Surface Methodology (RSM)

Cashew apple is one of the promising food material sources because this fruit contains high nutrtional values. This study aims for developing cashew apple juice into a new beverage and contributing to increase economic value for the byproduct of cashew industry. In this study, by using Reponse surface methodology (RSM), four different factors (juice concentration, %acid, %aroma, Brix) in mixing cashew apple juice product were examined to determine their optimum value in order to obtain the highest acceptance of the final product. The results of performed experiments showed that the combination of juice concentration 36%, acid 0.32%, aroma 0.017% and 13.7oBx gave the highest acceptance (6.925/9)

Femtosecond spectrally resolved nonlinear spectroscopy: Study of Si quantum dots

We report on the use of femtosecond spectrally resolved two colour three-pulse nonlinear spectroscopy to study the carrier relaxation in Si quantum dots. The third-order polarization for a coupled two-level system is applied for theoretical simulations. The optical phonon-assisted transition leads to a fast decay (20 fs) of hot carriers

A STUDY OF PHASE TRANSFORMATION IN SHAPE MEMORY ALLOY CuAl9Fe4

Microstructure and phase transformation in shape memory alloy Cu-Al (Fe addition: 9% Al, 4 % Fe) were investigated in this study. It is a material capable of restoring its original shape when impacted by a reasonable temperature or cyclic stress and production cost is not too expensive. In many years, shape memory alloys (SMA) based on Cu - Fe is considered to be very attractive to industrial and biomedical applications such as cardiovascular, orthopedic, surgery and production of spare parts and jigs. Original alloy exists β martensite and only exists 〖α^'〗 _1 (3R)+ 〖β'〗_1(9R) + 〖γ^'〗_(1 ) (2H) which is finely dispersed homogenously in microstructure after finishing shape memory transformation. Shape memory rate obtained 6%-24% corresponding to each deformation angle before the experiment. Phase transformation between these two phases during deformation as well as the heatingcooling process which create the basis for the unique properties of the alloy