Procol - A concurrent object-oriented language with protocols delegation and constraints

PROCOL is an object-oriented language with distributed delegation. It strongly supports concurrency: many objects may be active simultaneously, they execute in parallel unless engaged in communication. An object has exported operations, called Actions. Only one Action can be active at a time, however special interrupt Actions may interrupt regular Actions. Communication is performed via remote procedure call, or via a one-way synchronous message with short-time binding. In communications both client and server can be specified, either by object instance identifiers, or by type. Therefore client-server mappings may be 1-1, n-1, or 1-n, though only 1 message is transferred. PROCOL controls object access by an explicit per-object protocol. This protocol is a specification of the legality and serialization of the interaction between the object and its clients. It also provides for client type checking. The use of protocols in object communication fosters structured, safer and potentially verifiable information exchange between objects. The protocol also plays an important role as a partial interface specification. In addition it acts as a composition rule over client objects, representing relations with the client objects. PROCOL's communication binding is dynamic (run-time); it functions therefore naturally in a distributed, incremental and dynamic object environment. PROCOL also supports constraints, without compromising information hiding. An implementation is available in the form of a C extension

Partial hemopoietic chimerism in thalassemic recipients of normal bone marrow stem cells : selective advantage of normal erythropoiesis

Peripheral blood cells have a limited life span and are continuously replaced. Hemopoiesis is the production of new blood cells, which, in mice, under physiological circumstances, occurs in bone marrow (BM), spleenimd thymus. Current knowledge of hemopoiesis originates from the early 50's when it was observed that spleen and BM cell suspensions protected lethally irradiated animals from death due to bone marrow failure. Although this finding initially prompted a search for a humoral factor, it was soon demonstrated that the production of donor derived blood cells protected the animals from radiation inflicted death

Determinants of caregiving experiences and mental health of partners of cancer patients

BACKGROUND. Research regarding informal caregiving showed considerable individual variation in responses to cancer caregiving. The current longitudinal study examined determinants of caregiver outcomes in terms of caregiver experiences at 3 months and caregiver's mental health at 6 months after hospital discharge. It included both negative and positive dimensions of caregiving outcomes.METHODS. One hundred forty-eight patients with newly diagnosed colorectal carcinoma and their partners were included. Caregiver experiences were assessed by the Caregiver Reaction Assessment Scale, which contains four negative subscales (disrupted schedule, financial problems, lack of family support, and loss of physical strength) and one positive subscale (self-esteem). The mental health of the caregiver was assessed in terms of depression and quality of life. Possible determinants of the caregiver's experiences and mental health were categorized according to characteristics of the caregiver, the patient, and the care situation. Caregiving experiences were studied as a fourth additional category of possible determinants of the caregiver's mental health.RESULTS. Each domain of the caregiving experience was explained by different factors, with total explained variances ranging between 11-46%. Negative caregiver experiences were associated with a low income, living with only the patient, a distressed relationship, a high level of patient dependency, and a high involvement in caregiving tasks. Caregivers with a low level of education and caregivers of patients with a stoma were able to derive more self-esteem from caregiving. Although caregiving may lead to depression, especially in those experiencing loss of physical strength, caregivers may sustain their quality of life by deriving self-esteem from caregiving.CONCLUSIONS. It is important that professionals involved in the ongoing care of cancer patients and their families be aware of the increasing demands made on caregivers and the specific problems and uplifts they perceive in caregiving. Professional caregivers are urged to involve informal caregivers with care explicitly and continuously. However, specific attention to those caregivers who live only with the patient, those with a low income, those with a distressed relationship, and those with a high level of patient dependency and care involvement is warranted. Cancer 1999;86:577-88. (C) 1999 American Cancer Society.</p