Cut Tree Construction from Massive Graphs

The construction of cut trees (also known as Gomory-Hu trees) for a given graph enables the minimum-cut size of the original graph to be obtained for any pair of vertices. Cut trees are a powerful back-end for graph management and mining, as they support various procedures related to the minimum cut, maximum flow, and connectivity. However, the crucial drawback with cut trees is the computational cost of their construction. In theory, a cut tree is built by applying a maximum flow algorithm for $n$ times, where $n$ is the number of vertices. Therefore, naive implementations of this approach result in cubic time complexity, which is obviously too slow for today's large-scale graphs. To address this issue, in the present study, we propose a new cut-tree construction algorithm tailored to real-world networks. Using a series of experiments, we demonstrate that the proposed algorithm is several orders of magnitude faster than previous algorithms and it can construct cut trees for billion-scale graphs.Comment: Short version will appear at ICDM'1

Genome-wide SNP data of Izumo and Makurazaki populations support inner-dual structure model for origin of Yamato people

The “Dual Structure” model on the formation of the modern Japanese population assumes that the indigenous huntergathering population (symbolized as Jomon people) admixed with rice-farming population (symbolized as Yayoi people) who migrated from the Asian continent after the Yayoi period started. The Jomon component remained high both in Ainu and Okinawa people who mainly reside in northern and southern Japan, respectively, while the Yayoi component is higher in the mainland Japanese (Yamato people). The model has been well supported by genetic data, but the Yamato population was mostly represented by people from Tokyo area. We generated new genome-wide SNP data using Japonica Array for 45 individuals in Izumo City of Shimane Prefecture and for 72 individuals in Makurazaki City of Kagoshima Prefecture in Southern Kyushu, and compared these data with those of other human populations in East Asia, including BioBank Japan data. Using principal component analysis, phylogenetic network, and f4 tests, we found that Izumo, Makurazaki, and Tohoku populations are slightly differentiated from Kanto (including Tokyo), Tokai, and Kinki regions. These results suggest the substructure within Mainland Japanese maybe caused by multiple migration events from the Asian continent following the Jomon period, and we propose a modified version of “Dual Structure” model called the “Inner-Dual Structure” model

ABO式血液型の表現型と遺伝子型が不一致であった家族例

In the present study, we detected a familial case of ABO phenotype-genotype discrepancy. Although the observed phenotypes were B and O, the corresponding ABO genotypes were AB and AOG, respectively, by routine examination. Exons 6 and 7 of the ABO gene were sequenced and subsequently, the sequence of the allele responsible for ABO phenotype-genotype discrepancy was examined. Our results indicated that the Ax allele was present in 3 family members. By employing traditional serological methods, we further identified and confirmed that the allele Ax and the resulting Ax phenotype are responsible for ABO phenotype-genotype discrepancy.［目的］ABO式血液型の表現型と遺伝子型が不一致の家系を見出した.この家系について不一致の原因を究明し,血清学的な裏付けを行った.［対象と方法］家系内の三代にわたる8人を検査の対象とし,ABO式血液型の表現型と遺伝子型に不一致が認められた3人について詳細な遺伝子検査と血清学的検査を行った.［結果］遺伝子型検査でA型の亜型であるAxアリルを検出し,血清学的にAxの存在を確認した.表現型がそれぞれO型,B型であるにもかかわらず遺伝子型がAO型,AB型と判定されたものは実際にはAxO型,AxB型であった.［考察］Axは赤血球表面のA抗原が非常に少なく,血清学的にはOとほぼ同様の反応を示すため,本家系のAxの存在は知られることがなかった.またAxアリルはAアリルとOアリルのハイブリッドアリルであり,一般的な検出法ではAアリルと判定されてしまうため,遺伝子型から表現型を推定する際には注意が必要である

医療ネグレクトにより急性リンパ性白血病で死亡した1剖検例

小児腫瘍で最も多い前駆Ｂリンパ芽球性白血病で死亡した1例を経験したので報告する．2歳女児，特記すべき既往はない．呼吸不全で病院に搬送されたが，4時間後に死亡した．死亡2週間前に39℃台の発熱があったが，自然療法の薬草で改善した．1週間前には黄疸がみられるようになり，死亡当日に状態が悪化した．搬送時の病院での採血で白血球数の著明な上昇がみられたため，急性白血病を疑われた．司法解剖の結果，死因は前駆Ｂリンパ芽球性白血病と判明した．医学の進歩により，小児のリンパ芽球性白血病の90％程度は診断から5年以上生存している．しかしながら，死者の両親は西洋医学より補完代替療法（自然療法）を好んでおり，死者が産まれてから健康診断や予防接種で病院に連れて行ったことがなかった．死者が通常の医療を受けていれば，5年生存率は60％を超えていたと考えられ，両親の動機によらず，本事例は医療ネグレクトと考えられた．We report the case of 2-year-old girl who died of precursor B-cell acute lymphoblastic leukaemia(ALL), the most common cancer in　children. She had no remarkable medical history. She was transferred to a hospital because of respiratory distress and died 4 hours after arrival. Two weeks before death, she had a fever of 39℃, which subsided after the administration of a naturopathic herbal remedy. She developed jaundice 1 week before death, and her condition worsened on the day of death. Laboratory test results on admission showed a markedly elevated white blood cell count. Accordingly, the cause of death was suspected to be acute leukaemia. Forensic autopsy revealed the cause of death to be precursor B-cell ALL. With advancements in medical technology, the 5-year survival rate of children with ALL is nearly 90%. However, in this case, the deceasedʼs parents preferred complementary and alternative medicine (i.e., naturopathy) to evidence-based medicine and had not taken her to a hospital for a medical check-up or immunisation since she was an infant. Thus, if she had received routine medical care, she would have a more than 60% chance of being alive 5 years after diagnosis. Therefore, we conclude that the parents should be accused of medical neglect regardless of their motives

An Autopsy Case of Abnormal Behaviour Induced by Zolpidem

Zolpidem is a widely used ultrashort-acting non-benzodiazepine in clinical practice ; compared with benzodiazepines, it does not have side effects such as daytime hangover, rebound insomnia, and development of tolerance. We report an autopsy case of abnormal behaviour induced by zolpidem. A man in his 60ʼs had suffered from postherpetic neuralgia about 2 months ago and had been prescribed zolpidem for insomnia. According to his family, he had no memory of his actions such as striking a wall, taking his futon outside, and eating 5 times a day after he took zolpidem. Because his postherpetic neuralgia did not improve, he was hospitalized and treated with an epidural block. During hospitalization, he took off his clothes, removed the epidural block catheter by himself, and slept on othersʼ beds. He disappeared from the hospital one day ; the next day, he was found dead in a narrow water storage tank 10 km away from the hospital. He was thought to have driven a car by himself to reach the place. Forensic autopsy revealed that the cause of death was drowning. Zolpidem and several other drugs were detected by toxicological analysis of his blood ; the concentrations of these drugs were within therapeutic range. There are several reports about somnambulism induced by zolpidem such as sleepwalking, sleep driving, and eating. Considering the strange episodes following zolpidem administration, his behaviour on the day of his death was considered abnormal behavior induced by zolpidem

死後CT と剖検による死因が一致しなかった1例

A middle-aged man was found lying beside his bicycle on an early winter morning. The cause of death was diagnosed by clinicians as traumatic intracerebral hemorrhage and cerebral contusion with frontal bone fracture based on the findings of Computed Tomography (CT) of the head. However, forensic autopsy revealed that there were no evidences of intracerebral hemorrhage and left frontal bone fracture but the defect of golf ball size on the frontal lobe which was considered to be a complication from the old cerebral contusion and old bone fracture. The bleeding and pooling blood from subarachnoid hemorrhage (SAH) to the frontal lobe defect had the appearance of an intracerebral hemorrhage. Disruption of left renal artery was found and the cause of death was diagnosed as massive hemorrhage due to this rupture. Although postmortem CT is a useful tool for obtaining information on the body prior to conducting an autopsy, it should be used with extreme caution.ある冬の早朝，公園で中年男性が自転車の横で倒れているのを発見された．頭部CT の結果から，臨床医は頭蓋骨骨折を伴う外傷性脳内出血と脳挫傷が死因と考えた．しかしながら，解剖の結果，外傷性脳内出血と頭蓋骨骨折は認められず，陳旧性の脳挫傷による欠損と陳旧性骨折を認め，欠損部位へのくも膜下出血からの血液の流入が脳内血腫のようにみえたと考えられた．一方，左腎動脈破裂が認められ，大量出血が死因と考えられた．死後CT により遺体の情報を得ることは非常に有効だが，十分な注意が必要である